Patent Application
20080089631
The present invention relates to a raceway ring composing a radial ball bearing, in which a rotating accuracy is not required to be so high. Such the radial ball bearing is incorporated into a rotary supporting portion of an electric motor, which is assembled to various electric appliances such as a vacuum cleaner, a ventilating fan and so forth, or incorporated into a rotary supporting portion of various auxiliary machines for automobile use. The present invention also relates to an improvement in the manufacturing method of the raceway ring.
Into rotary supporting portions of various rotary devices, a radial ball bearing 1 shown in
In order to make raceway rings of the outer ring 2 and the inner ring 3 described above composing the radial ball bearing 1 described above, it is common that a partially finished material, the shape and size of which are similar to those of a completely finished product, is obtained first by means of forging and cutting. Then, this partially finished material is subjected to heat treatment so as to harden a surface of the partially finished material and then surfaces of the outer ring raceway 5 and the inner ring raceway 6 are polished so that the size and surface hardness can become predetermined values. In this way, the raceway ring is formed.
The above manufacturing method of the inner ring is disadvantageous in that the yield of material is deteriorated and further the manufacturing cost is raised.
In Patent Documents 1 and 2, a method is described in which a raceway ring of a radial ball bearing is made mainly by means of forging.
First, in the invention described in Patent Document 1, a compound partially finished material, in which a partially finished material for making an outer ring, and a partially finished material for making an inner ring, are integrated with each other into one body, is made by means of forging. Then, this compound partially finished material is divided into a partially finished material for making an outer ring and a partially finished material for making an inner ring. In the case of the invention described in Patent Document 1, when a diameter of a portion of the partially finished material for making an inner ring is expanded, an inner ring having a deep groove type inner ring raceway on the outer circumferential face is obtained.
Next, Patent Document 2 describes an invention relating to a method in which a ring-shaped material, which is obtained when a steel pipe made by means of hot extrusion is cut off, is compressed (upsetting) in the axial direction by a vertical type press and a partially finished material for an outer ring having a deep groove type outer ring raceway on the inner circumferential face is manufactured.
In the inventions described in the above Patent Documents 1 and 2, in the case of the invention described in Patent Document 1, a compound partially finished material, the volume of which is large, is made by means of forging at the initial stage of processing. Therefore, at the time of making the compound partially finished material, a load given to the material in the process of forging is increased and further stress given to a metallic die such as a punch of the forging machine is also increased. As a result, an amount of elastic deformation of each portion of the forging machine including the metallic die is increased. Therefore, it is difficult that the accuracy of the size and shape of the compound partially finished material and the partially finished material, which is formed out of this compound partially finished material, for making an outer and an inner ring is maintained to be sufficiently high. Especially when the compound partially finished material, the volume of which is large, is made by means of cold forging, an excessively heavy load is given to the metallic die. Accordingly, it becomes difficult to ensure the durability of the metallic die. Accordingly, the compound partially finished material is machined by means of hot forging or warm forging. However, in the case of hot forging or warm forging, in order to positively engage the metallic dies with each other irrespective of a difference of an amount of thermal expansion, a gap formed in the engaging portion in the case of hot forging or warm forging must be larger than the gap formed in the engaging portion in the case of cold forging. Therefore, it becomes difficult that the accuracy of the sizes of the outer and the inner diameter of the obtained compound partially finished material are maintained to be sufficiently high. It also becomes difficult that the accuracy of the size and the shape of the inner and the outer circumferential face is maintained to be sufficiently high. It also becomes difficult that the accuracy of the concentricity of the inner and the outer circumferential face is maintained to be sufficiently high. As a result, even when the ball bearing is used for a device in which a high rotary accuracy is not required, it becomes difficult that the dimensional accuracy and the deflection accuracy of the inner and the outer diameter of the inner and the outer ring are maintained to be sufficiently high. It is impossible to form engaging grooves for engaging outer circumferential edges of sealing plates on both sides of the inner circumferential face of the outer ring by means of plastic working. Therefore, it becomes necessary to form these engaging grooves by means of cutting. Accordingly, it is difficult to sufficiently reduce the manufacturing cost.
In the case of the invention described in Patent Document 2, the ring-shaped material is obtained when a steel pipe, which has been made by means of hot extrusion, is cut off. Therefore, it is difficult that the size of the inner and the outer diameter of this material is maintained at high accuracy. Further, it is difficult that the size, shape and concentricity of the inner and the outer circumferential face are maintained at high accuracy. As a result, the accuracy of the size of the inner and the outer diameter of the obtained outer ring can not be maintained high. Further, the deflection accuracy of the inner and the outer diameter of the obtained outer ring can not be maintained high. When the ring-shaped material is made by cutting a steel pipe, it takes time and labor. Therefore, the productivity is deteriorated, which raises the manufacturing cost. Further, it is necessary to conduct decarbonization on the partially finished material for making the outer ring when it is cut. From this viewpoint, the manufacturing cost is raised.
Patent Documents 3 and 4 disclose a manufacturing method of a raceway ring for a radial ball bearing in which a circumferential face of a ring-shaped material, the diameter of which is smaller than that of the raceway ring to be manufactured, is pressed by a mandrel so as to transfer an outer circumferential face shape of this mandrel onto the circumferential face of the ring-shaped material. Therefore, a diameter of this ring-shaped material is expanded to obtain a raceway ring, the diameter of which is desired. However, in this conventional method described in Patent Documents 3 and 4, it is difficult to stabilize behavior of the ring-shaped material under the condition that the mandrel is pressed. Therefore, it is impossible to accurately transfer the shape of the outer circumferential face of the mandrel onto the circumferential face of the ring-shaped material. Further, it is difficult that the circularity of the thus obtained raceway ring is maintained to be sufficiently high. Therefore, even when the ball bearing is applied to a use in which a high rotary accuracy is not required, it is difficult to maintain the dimensional accuracy sufficiently high. In the case of the invention described in Patent Document 4, it is necessary to remove material after the completion of plastic working. Therefore, a reduction of the manufacturing cost is limited.
Therefore, in the present invention, the inventors devised a method in which a raceway ring composing a radial ball bearing, which can be applied to a practical use in which a high rotary accuracy is not required, is manufactured at a low manufacturing cost while a practically, sufficiently high accuracy is being ensured. However, even in this case, when consideration is given to practical accuracy of the radial ball bearing finally obtained, it is important that the accuracy of the shape and the size of the ring, which becomes a material of the outer ring or the inner ring, is maintained sufficiently high.
Concerning the manufacturing method of this ring-shaped component, Patent Document 5 discloses an invention in which a ring-shaped component is formed when a column-shaped material is subjected to cold working. However, in the case of the invention described in Patent Document 5, no restriction is made in the size of the axial direction at the time of conducting cold work. Accordingly, it is impossible to ensure the accuracy in the axial direction of the thus obtained ring-shaped component. As a result, it is impossible to ensure the accuracy of the volume. For the above reasons, it is difficult to manufacture a raceway ring, which can be practically used, only by conducting plastic work on this ring-shaped component.
Patent Document 1: Official gazette of Japanese Patent Unexamined Publication No. JP-A-5-277615
Patent Document 2: Official gazette of Japanese Patent Unexamined Publication No. JP-A-2001-150082
Patent Document 3: Official gazette of Japanese Patent Unexamined Publication No. JP-A-59-212142
Patent Document 4: Official gazette of Japanese Patent Unexamined Publication No. JP-A-56-111533
Patent Document 5: Official gazette of Japanese Patent Unexamined Publication No. JP-A-2000-94080
The present invention has been accomplished in view of the above circumstances. The present invention provides a raceway ring for a radial ball bearing and a manufacturing method thereof capable of obtaining an inner ring and an outer ring, which are raceways composing a radial ball bearing applied to the aforementioned use in which high rotary accuracy is not required, at a low manufacturing coast while practically, sufficiently high accuracy is being maintained.
Further, in view of the above circumstances, the present invention is to provide a manufacturing method of easily manufacturing a high accurate raceway ring capable of sufficiently ensuring practical accuracy of a radial ball bearing which is finally obtained as a material for making an inner ring or an outer ring composing the radial ball bearing by cold working.
According to a first aspect of the invention, there is provided a manufacturing method of a raceway ring for a radial ball bearing, the radial ball bearing comprising:
the raceway ring comprising at least one of:
a plurality of balls rollably provided between the inner ring raceway and the outer ring raceway,
a high accurate material working process of preparing a high accurate material of which volume is substantially the same as that of the raceway ring of the radial ball bearing which is a finished product by cold working; and
a raceway ring working process of plastically deforming the high accurate material by cold working and forming the raceway surface on the axially intermediate portion of either outer or inner circumferential face,
wherein working for removing material is not conducted before a heat treatment.
According to a second aspect of the invention, it is preferable that the manufacturing method as set forth in the first aspect of the invention further comprising a finishing process of finishing the raceway surface by rolling process after the raceway ring working process.
According to a third aspect of the invention, as set forth in the second aspect of the invention, it is preferable that recess portions for sealing, which are provided on an entire circumference of both axial ends of either outer or inner circumferential face of the raceway ring at positions which are set to oppose each other via the raceway surface in an axial direction, are finished by rolling process simultaneously when the raceway surface is finished in the finishing process.
According to a fourth aspect of the invention, as set forth in the second aspect of the invention, it is preferable that the raceway ring working process of working the outer ring of the ball bearing comprising:
a first process of forming a primary partially finished material in such a manner that:
a second process of forming a secondary partially finished material in such a manner that:
a third process of reducing an outer diameter of the large diameter portion of the secondary partially finished material so as to agree with an outer diameter of the small diameter portion.
According to a fifth aspect of the invention, as set forth in the fourth aspect of the invention, it is preferable that
the outer ring raceway is of the deep groove, and
in the third process, the outer ring raceway of the deep groove is formed on the axially intermediate portion of the inner circumferential face by forming a second curved face for the raceway surface, which is symmetrical with the curved face for the raceway surface, on inner circumferential surface of the axially intermediate portion so as to continue to the curved face for the raceway surface.
According to a sixth aspect of the invention, as set forth in the fifth aspect of the invention, it is preferable that the outer ring includes engagement grooves for engaging an outer circumferential edge portion of a tight-sealing plate provided at both axially end portions on the inner circumferential face,
the manufacturing method of the raceway ring for the radial ball bearing further comprises:
According to a seventh aspect of the invention, the manufacturing method as set forth in the sixth aspect of the invention further comprising:
a finishing process of simultaneously finishing the outer ring raceway and both engagement groove portions by rolling process after the after-process.
According to an eighth aspect of the invention, as set forth in the first aspect of the invention, it is preferable that the raceway ring working process for working the inner ring of the ball bearing comprising:
a first process of forming a partially finished material in such a manner that forming a curved face for the first raceway face, which has arcuate shape in cross section and becomes a portion of the inner ring raceway, on an outer circumferential face of axially intermediate portion while reducing a diameter of the cylindrical high accurate material, wherein one half portion in the axial direction with respect to the curved face for the first raceway of the partially finished material is made a small diameter portion and, the other half portion in the axial direction of the partially finished material is a large diameter portion; and
a second process of expanding the inner diameter of the small diameter portion, which is a half portion in the axial direction of the partially finished material, to the same inner diameter as that of the other half portion in the axial direction, and forming a curved face for the second raceway, which becomes a residual portion of the inner ring raceway, on a portion continuing to the curved face for the first raceway.
According to a ninth aspect of the invention, as set forth in the eighth aspect of the invention, it is preferable that the inner ring raceway is of the deep groove,
the raceway ring working process further including an intermediate process conducted between the first and the second process, the intermediate process compressing an axially part of the partially finished material by working and forming into a secondary partially finished material, of which distribution of radial thickness along the axial direction in a portion axially adjacent to the curved face for the first raceway surface agrees with a distribution of the thickness in a corresponding portion of the inner ring to be manufactured,
wherein, in the second process, forming the curved face for the second raceway surface, which is symmetrical with the curved face for the first raceway surface, so as to continue to the curved face for the first raceway surface by using the curved face for the first raceway surface, of which thickness distribution is determined, on the axially intermediate portion, to thereby form the inner ring raceway of the deep groove.
According to a tenth aspect of the invention, as set forth in the ninth aspect of the invention, it is preferable that the inner ring has a pair of sealing step portions, which makes slide-contact or come close to an inner circumferential edge portion of the tight-sealing plate, on both axial ends of the outer circumferential face,
the manufacturing method further comprising:
a preliminary process of forming a preliminary intermediate material by forming step portions, of which outer diameter are smaller than the outer diameter of axially intermediate portion, at both axial end portions of the high accurate material before the first process; and
an after-process of plastically working and forming the step portions into both sealing step portions after the second process.
According to an eleventh aspect of the invention, it is preferable that the manufacturing method as set forth in the tenth aspect of the invention, further comprising:
a finishing process of simultaneously finishing the inner ring raceway and the step portions for both sealing portions by rolling process after the after-process.
According to a twelfth aspect of the invention, there is provided a manufacturing method of a cylindrical raceway ring for a radial ball bearing, in which a cross-section arcuate raceway surface is formed on entire of a circumference at an axially intermediate portion on either circumferential face,
the manufacturing method comprising:
a first process of conducting a first forging process to obtain a primary partially finished material in such a manner that pressing a cylindrical material, of which volume is substantially the same as that of a finished product, with a pair of metallic dies which are relatively displaced in the axial direction, and deforming a diameter of axially one half of the material to make a small diameter portion, and the other half is made a large diameter portion, a second process of conducting a second cold forging process to obtain a secondary partially finished material in such a manner that pressing the primary partially finished material with a pair of metallic dies which is different from that used in the first process and are relatively displaced in the axial direction, so that a distribution of radial thickness along the axial direction on at least a portion of the primary partially finished material where the raceway surface is formed agrees with the thickness of the portion where a raceway surface of the completed raceway ring is formed; and
a third process of plastically deforming a part of the secondary partially finished material in radial direction to form the raceway surface by conducting a rolling process which presses the secondary partially finished material so that inner circumferential face and outer circumferential face thereof come close to each other while rotating the secondary partially finished material.
According to a thirteenth aspect of the invention, as set forth in the twelfth aspect of the invention, it is preferable that
the raceway ring includes engagement grooves for engaging a circumferential edge portion of a tight-sealing plate provided at both axially end portions on the circumferential face formed with the raceway surface,
the manufacturing method further comprising:
a preliminary process of forming step portions which are recessed in the radial direction from the axially intermediate portion at both axial end portions thereof to obtain a preliminary partially finished material prior to the first process; and
a third process of forming the engagement grooves in the step portions. According to a fourteenth aspect of the invention, there is provided a manufacturing method of a cylindrical raceway ring for a radial ball bearing, in which a cross-section arcuate raceway surface is formed on entire of a circumference at an axially intermediate portion on either circumferential face which is to be worked side circumferential face, the method comprising:
preparing a cylindrical material, which has volume substantially the same as that of a finished product, and a diameter of the not-worked side circumferential face, which is opposite side relative to a face on which the raceway surface is formed, is substantially the same as that of a finished product;
supporting the not-worked side circumferential face by so as to be fitted to a support side circumferential face provided on a receiving member without substantially generating any gap; and
rotating a working side rotating member relative to the receiving member, while pressing the working side circumferential surface of a working side rotating member, which has a generating line shape agreeing with a generating line shape of the worked side circumferential face in a finished product, in a radial direction, to thereby process the worked side circumferential face as a finished product shape having at least the raceway surface.
According to a fifteenth aspect of the invention, as set forth in the fourteenth aspect of the invention, it is preferable that stepped portions are formed in both axial end portions of the worked side circumferential face of the material in order to form step portions, which are recessed in the radial direction from a radially central portion of the worked side circumferential face, on entire of the circumference in both axial end portions of the worked side circumferential face of a finished product, and
both stepped portions are worked simultaneously with the raceway surface when a worked side rotary member is pressed onto the worked side circumferential face.
According to a sixteenth aspect of the invention, as set forth in the fifteenth aspect of the invention, it is preferable that step faces existing between both step portions, which are provided in both axial end portions of the worked side circumferential face of the material, and the axially central portion are formed into inclined faces which incline so as to come close to each other when the step faces are separate from the not-worked circumferential face with respect to the radial direction, and
an inclination angle of both step faces with respect to a virtual plane existing in a direction perpendicular to a central axis of the material is larger than an inclination angle of the step face existing in a portion corresponding to the completed raceway ring and not more than 15°.
According to a seventeenth aspect of the invention, as set forth in the fourteenth aspect of the invention, it is preferable that both axially end faces of the material to make the raceway ring are inclined faces which incline so as to come close to each other when the faces are separate from the not-worked side circumferential face, and
an inclination angle of both axially end faces with respect to a virtual plane existing in a direction perpendicular to the central axis of the material is not more than 20°.
According to an eighteenth aspect of the invention, there is provided a radial ball bearing comprising:
a raceway ring comprising at least one of:
a plurality of balls rollably provided between the inner ring raceway and the outer ring raceway,
wherein the raceway ring is worked in such a manner that a cylindrical high accurate material made by cold working, of which volume is substantially the same as that of a finished product, is plastically deformed by cold working to thereby process a surface shape including the raceway substantially the same as the shape of the finished product.
According to a nineteenth aspect of the invention, there is provided a cylindrical raceway ring for a radial ball bearing, in which a cross-section arcuate raceway surface is formed on entire of a circumference at an axially intermediate portion on either circumferential face,
wherein a surface shape including the raceway surface is processed by conducting cold forge rolling process on a partially finished product, which is obtained by plastically deforming a cylindrical material having volume substantially the same as that of a finished product, to plastically deform at least a part of the partially finished product in a radial direction.
According to a twentieth aspect of the invention, as set forth in the nineteenth aspect of the invention, it is preferable that
a shape of the outer circumferential face of the partially finished material is formed in such a manner that a direction of a change in the outer diameter from a portion, of which outer diameter is the largest, to both axially end faces is not inverted, and the shape of the outer circumferential face of the partially finished material has no under-cut portion, and
a shape of the inner circumferential face of the partially finished material is formed in such a manner that a direction of a change in the inner diameter from a portion, of which inner diameter is the smallest, to both axially end faces is not inverted and the shape of the inner circumferential face of the partially finished material has no under-cut portions.
According to a twenty-first aspect of the invention, there is provided a manufacturing method of a high accurate metallic ring comprising:
a restriction process of restricting either inner or outer circumferential face of a cylindrical material, of which volume is larger than that of the high accurate ring to be manufactured, so as to maintain its diameter;
a compression process of compressing the cylindrical material in an axial direction by cold working while not restricting a diameter of the other circumferential face so as not to change its diameter, to form a partially finished material in which an axial dimension of thereof agrees with an axial dimension of the high accurate ring, and an excess thickness portion exceeding the volume of the high accurate ring is released to a direction in which the other circumferential face is swelled in the radial direction; and
a removing process of removing the excess thickness portion so as to form a cylindrical ring of which inner diameter, outer diameter and axial length are predetermined values.
According to a twenty-second aspect of the invention, as set forth in the twenty-first aspect of the invention, it is preferable that
the removing process comprising:
an wringing process of wringing the excess thickness portion existing on the other circumferential face by a wringing jig, of which radial dimension agrees with a radial dimension of the high accurate ring, so as to collect the excess thickness portion at one portion with respect to the axial direction on the other circumferential face, to form a flange portion protruding in the radial direction in this one portion, and to make a diameter of the residual portion of the other circumferential face agree with the radial dimension of the high accurate ring; and
a removing process of removing the flange portion by punching after the completion of the wringing process.
According to a twenty-third aspect of the invention, as set forth in the twenty-first aspect of the invention, it is preferable that
the removing process including:
a shaving process of shaving the excess thickness portion existing on the other circumferential face by a punch, of which diameter agrees with a radial dimension of the high accurate ring to be manufactured.
According to a twenty-fourth aspect of the invention, it is preferable that the manufacturing method as set forth in the twenty-first aspect of the invention further comprising:
a process of compressing a columnar billet in the axial direction to form a disk-shaped partially finished material;
a process of compressing an axially central portion of the disk-shaped partially finished material in the axial direction to reduce axial length in the axially central portion; and
a rearwardly pushing process of compressing
a portion on an outer diameter side of the disk-shaped partially finished material rearward with respect to a pushing direction so as to deform the disk-shaped partially finished material into a cylindrical shape to thereby form a bottomed secondary partially finished material, wherein
these processes are provided before the restriction process, and
a cylindrical material is formed by punching a bottom portion from the secondary partially finished material.
According to a twenty-fifth aspect of the invention, it is preferable that the manufacturing method as set forth in the twenty-first aspect of the invention further comprising:
an inversion forming process of twisting a cross-section shape of a ring-shaped partially finished material, which is manufactured by punching a metallic plate by angle of 90° to thereby form a cylindrical material,
wherein the inversion forming process is conducted before the restriction process.
According to a twenty-sixth aspect of the invention, as set forth in the twenty-first aspect of the invention, it is preferable that the high accurate ring is a material used for manufacturing an inner ring composing a radial ball bearing by cold working, and
one circumferential face of the high accurate ring is an outer circumferential face and the other circumferential face of the high accurate ring is an inner circumferential face.
According to a twenty-seventh aspect of the invention, as set forth in the twenty-first aspect of the invention, it is preferable that the high accurate ring is a material used for manufacturing an outer ring composing a radial ball bearing by cold working, and
one circumferential face of the high accurate ring is an inner circumferential face and the other circumferential face of the high accurate ring is an outer circumferential face.
According to a twenty-eighth aspect of the invention, there is provided a manufacturing method of a high accurate metallic ring comprising:
a process of compressing a billet-shaped material, of which volume is larger than that of the high accurate ring to be manufactured to thereby form a disk-shaped partially finished material, of which thickness dimension along an axial direction is large in a central portion and becomes small when it comes to an outer circumferential edge portion;
a process of forming a circular hole in a central portion of the disk-shaped partially finished material to thereby form a ring-shaped partially finished material, of which volume is the same as that of a high accurate ring; and
an inversion working process of contracting a portion on the outer diameter side of the ring-shaped partially finished material radially inwardly; and expanding a portion on the inner diameter side of the ring-shaped partially finished material radially outwardly, to make each portion in the circumferential direction in a cross-section of the ring-shaped partially finished material parallel each other in the axial direction, to thereby form the ring-shaped partially finished material into a cylindrical ring, of which inner diameter, outer diameter and axial length are made predetermined values
wherein a change in angle in the inversion working process is not more than 90°.
According to a twenty-ninth aspect of the invention, as set forth in the twenty-eighth aspect of the invention, it is preferable that when a circular hole is formed in the central portion of the disk-shaped partially finished material, a recess portion is formed at least on one side of both sides in the axial direction of a portion to be removed so that a volume of the portion to be removed is reduced.
According to a thirtieth aspect of the invention, as set forth in the twenty-ninth aspect of the invention, it is preferable that the process of forming the ring-shaped partially finished material including:
pressing the disk-shaped partially finished material, on which the recess portion is formed, in the axial direction while restricting an outer circumferential edge portion of the disk-shaped partially finished material so as not expand the outer diameter;
contracting the thickness along the axial direction to a proper value;
releasing a surplus of the volume to the recess portion; and
punching a central portion of the disk-shaped partially finished material including the recess portion from the ring-shaped partially finished material.
According to a thirty-first aspect of the invention, as set forth in the twenty-eighth aspect of the invention, it is preferable that
the process of forming the ring-shaped partially finished material including:
a process of forming an elementary circular hole, which is to be a circular hole, in a central portion of the disk-shaped partially finished material to thereby form an elementary ring-shaped partially finished material;
a process of pressing the elementary ring-shaped partially finished material in the axial direction while restricting an outer circumferential edge portion so as not to expand its outer diameter and reducing the thickness in the axial direction to a proper value and releasing a surplus of the volume to an inner circumferential edge portion of the elementary circular hole; and
a process removing the surplus existing in the inner circumferential edge portion from the elementary circular hole.
According to a thirty-second aspect of the invention, as set forth in the twenty-eighth aspect of the invention, it is preferable that while an outer circumferential edge portion of the disk-shaped partially finished material is being restricted so that an outer diameter of the disk-shaped partially finished material is be expanded, a circular hole is formed in a central portion of the disk-shaped partially finished material and a recess portion is formed only on one side in the axial direction of a portion to be removed so as to reduce a volume of the portion to be removed and
a shape of the disk-shaped partially finished material is formed into a substantial circular truncated cone in which a portion on the outer diameter side on the side on which the recess portion becomes a partial conical recess face so that a change in the angle is suppressed to be smaller than 90° at the time of inversion working in which the ring-shaped partially finished material is formed into a cylindrical ring.
According to a thirty-third aspect of the invention, as set forth in the twenty-eighth aspect of the invention, it is preferable that at the time of manufacturing the disk-shaped partially finished material by compressing the billet-shaped material in the axial direction, by restricting both radial sides at both axial ends of the billet-shaped material or the preliminary partially finished material, which is obtained when the billet-shaped material is worked, a diameter of both axial end portions of the billet-shaped material or the preliminary partially finished material is prevented from being expanded and
when a portion including both axially end faces of the material or the preliminary partially finished material is removed, a circular hole is formed and a ring-shaped partially finished material is obtained.
According to a thirty-fourth aspect of the invention, there is provided a manufacturing apparatus used for a manufacturing method of a high accurate metallic ring of which manufacturing method comprising:
a process of compressing a billet-shaped material, of which volume is larger than that of the high accurate ring to be manufactured to thereby form a disk-shaped partially finished material, of which thickness dimension along an axial direction is large in a central portion and becomes small when it comes to an outer circumferential edge portion;
a process of forming a circular hole in a central portion of the disk-shaped partially finished material to thereby form a ring-shaped partially finished material, of which volume is the same as that of a high accurate ring; and
an inversion working process of contracting a portion on the outer diameter side of the ring-shaped partially finished material radially inwardly; and expanding a portion on the inner diameter side of the ring-shaped partially finished material radially outwardly, to make each portion in the circumferential direction in a cross-section of the ring-shaped partially finished material parallel each other in the axial direction, to thereby form the ring-shaped partially finished material into a cylindrical ring, of which inner diameter, outer diameter and axial length are made predetermined values
wherein a change in angle in the inversion working process is not more than 90°,
wherein at the time of manufacturing the disk-shaped partially finished material by compressing the billet-shaped material in the axial direction, by restricting both radial sides at both axial ends of the billet-shaped material or the preliminary partially finished material, which is obtained when the billet-shaped material is worked, a diameter of both axial end portions of the billet-shaped material or the preliminary partially finished material is prevented from being expanded and
when a portion including both axially end faces of the material or the preliminary partially finished material is removed, a circular hole is formed and a ring-shaped partially finished material is obtained,
the manufacturing apparatus comprising:
a fixing block;
a die having a lower side central hole, wherein under a condition that the die descends until it comes into contact with an upper face of the fixing block when a strong force is given to the die, the lower side central hole is capable of internally engaging with a lower end portion of the billet-shaped material or the preliminary partially finished material, which is obtained when the billet-shaped material is worked and is elastically supported at an upper portion of the fixing block;
a counter punch inserted into the lower side central hole so as to be elevated with respect to the die;
a ring punch having an upper side central hole, wherein
under the condition that the ring punch ascends until it comes into contact with a lower face of a ram when a strong force is given to a part of the ram of a press machine provided upside of the die so as to be coaxial with the die, the upper side central hole is capable of internally engaging with the upper end portion of the billet-shaped material or the preliminary partially finished material, which is obtained when this billet-shaped material is worked and is elastically supported at a lower portion of the ram; and
a punch inserted into the upper side central hole so as to elevate with respect to the ring punch.
According to a thirty-fifth aspect of the invention, as set forth in the thirty-fourth aspect of the invention, it is preferable that before at least working of the disk-shaped partially finished material is completed, the counter punch is supported without being elevated with respect to the fixing block and the punch is supported without being elevated with respect to the ram,
under a condition that a lower face of the die comes into contact with an upper face of the fixing block, an upper end face of the counter punch exists at a position recessed downward from an upper face of the die, and
under the condition that an upper face of the ring punch comes into contact with a lower face of the ram, the punch exists at a position recessed upward from a lower face of the ring punch.
According to a thirty-sixth aspect of the invention, there is provided a manufacturing method of a high accurate metallic ring comprising:
a primary partially finished material forming process of:
a division process of cutting off the primary partially finished material in boundary portion between an outer circumferential face of the cylindrical portion and an inner circumferential edge of the flange portion at a radially intermediate portion, to thereby divide the cylindrical portion which is made as a first high accurate ring, and the flange portion which is made as a ring-shaped secondary partially finished material; and
a second high accurate ring forming process of inverting
a direction of a cross-section of the secondary partially finished material by angle of 90° to thereby obtain a cylindrical second high accurate ring, of which inner diameter, outer diameter and axial length are predetermined values.
According to a thirty-seventh aspect of the invention, as set forth in the thirty-sixth aspect of the invention, it is preferable that in the primary partially finished material forming process, by compressing the material in a direction that both axial ends come close to each other, forming a boss portion, of which axial thickness in the radially central portion is larger than the axial thickness in the radially outward portion, and a flange portion in a peripheral portion of the boss portion,
crushing a central portion of the boss portion in the axial direction so as to reduce the axial thickness of the central portion and also to increase the axial thickness of a portion close to the outer diameter of the boss portion, and
punching a portion of the central portion, of which thickness is reduced, to form a circular hole.
According to a thirty-eighth aspect of the invention, as set forth in the thirty-sixth aspect of the invention, it is preferable that in the primary partially finished material forming process, by compressing both central portions of axially end faces of the material, in a direction that they come close to each other so as to reduce the axial thickness of the central portion, so as to form an elementary cylindrical portion axially protruding from both axial end faces of the flange portion, and then the portion in the central portion, of which thickness is reduced, is punched to form a circular hole.
According to a thirty-ninth aspect of the invention, it is preferable that the manufacturing method as set forth in the thirty-sixth aspect of the invention, further comprising:
a process, which is provided between the division process and the second high accurate ring forming process, in which
According to a fortieth aspect of the invention, as set forth in the thirty-sixth aspect of the invention, it is preferable that the axial thickness of the flange portion, which is formed in the first high accurate ring forming process, is increased in a portion close to the central portion in the radial direction and decreased in the outer circumferential edge portion, and
in the second high accurate ring forming process, an inversion working, in which contracting a portion close to the outer diameter of the secondary partially finished material radially inwardly and expanding a portion close to the inner diameter radially outwardly, is conducted.
According to the raceway ring for a radial ball bearing composed as described above and the manufacturing method thereof of the present invention, a raceway ring composing a radial ball bearing, which is applied to the above use, the rotation accuracy of which is not so high, can be obtained at a low manufacturing cost while the accuracy, which is sufficiently high for practical use, is being maintained.
A cylindrical material (a high accurate material), the volume of which is the same as that of a raceway ring to be manufactured (In the case where finish working is conducted being accompanied by the removal of the material, consideration is given to it.), is plastically deformed by cold working to form the raceway ring. Therefore, accuracy of the shape and size of this raceway ring can be maintained high.
Of course, when the accuracy of working is enhanced, the present invention can be applied to a raceway ring for a ball bearing for which high accuracy is required.
According to the manufacturing method of the above highly accuracy ring of the present invention, it is possible to easily and efficiently manufacture a high accurate ring, the inner diameter, the outer diameter and the size in the axial direction of which are regulated to be proper values, and the central axes of the inner and outer circumferential faces of which strictly agree with each other, by a high yield. As a result, the cost for working an outer ring or an inner ring composing a radial ball bearing, which is made when the high accurate ring is worked, can be reduced while a sufficiently high performance is being maintained for the practical use.
Of course, when the accuracy of working is enhanced, the present invention can be applied to a high accurate ring used for manufacturing a raceway ring of a ball bearing for which high accuracy is required.
Referring to FIGS. 1 to 53, embodiments of the present invention will be explained. First, referring to FIGS. 1 to 30, a manufacturing method of a raceway ring will be explained below. After that, referring to FIGS. 31 to 53, a manufacturing method of a high accurate ring, which is preferably used for manufacturing the raceway ring, will be explained.
First, a manufacturing method of a raceway ring will be explained below.
A method of forming the raceway ring of the present invention is divided into five processes. The first process is to form a step portion, the second process is to contract a pipe, the third process is to extrude an inner and an outer diameter, the fourth process is to form a raceway, and the fifth process is to form a sealing face. Each process is executed by cold working, which is one of the characteristics of the present invention. Embodiments described later are distinguished from each other by a process to which roller working is applied.
The raceway ring includes an outer ring and an inner ring. In the following embodiments, a manufacturing method of the outer ring will be explained. After that, a manufacturing method of the inner ring will be explained. Embodiments 1 to 6 shown in FIGS. 1 to 15 relate to the manufacturing method of the outer ring. Embodiments 7 to 12 shown in FIGS. 16 to 30 relate to the manufacturing method of the inner ring.
In the first and the seventh embodiment, rolling process is not used in the processes of manufacturing the outer ring and the inner ring, that is, all processes are executed without using rolling processing.
In the second and the eighth embodiment, rolling process is applied to the fifth process in the process of manufacturing the outer ring and the inner ring.
The third to the fifth embodiment and the ninth to the eleventh embodiment are embodiments in which rolling process is applied to the fourth and the fifth process in the manufacturing process of an outer and an inner ring.
In the sixth and the twelfth embodiment, rolling process is applied to the second to the fifth process in the process of manufacturing the outer ring and the inner ring.
In any embodiment, the first process is executed by means of press forming in which metallic dies are used. Each embodiment will be explained in detail below.
First of all, referring to Embodiments 1 to 6, a method of forming an outer ring of the present invention will be explained.
FIGS. 1 to 6 are views showing Embodiment 1 of the present invention. The present invention is characterized in that: after a cylindrical high accurate material 8 (shown in
In the case of the present embodiment, the high accurate material 8 shown in
The high accurate material 8 is formed into the preliminary partially finished material 9 as follows. An outer circumferential face of this high accurate material 8 is internally engaged with an inner circumferential face of a holding die not shown. An inner circumferential face of this high accurate material 8 is externally engaged with a core. In this state, a forward end face of a punch not shown is pressed onto the entire circumferences of the inner diameter side half portions on both axially end faces (the vertical direction of
Therefore, pipe contraction working, in which a diameter of a portion (a portion except for one end portion (an upper end portion in
In this connection, in the example shown in the drawing, when a convex face portion 20 is formed in a portion on the forward end face of the punch 17, a concave face portion 21, the cross section of which is formed into an arc, is formed in a portion of the inner circumferential face of the primary partially finished material 10 all over the circumference. Punch 17 forms this concave face portion 21 at an early stage of working in which the preliminary partially finished material 9 is formed into the primary partially finished material 10. Accordingly, in the process in which the outer diameter is contracted so that the primary partially finished material 10 can be formed by contracting the diameter of a portion of the preliminary partially finished material 9, working stress is given only to a contact portion of the curved face portion 19 with the outer circumferential face of the preliminary partially finished material 9 except for the initial stage described before. Accordingly, the outer circumferential face of the primary partially finished material 10 can be plastically worked with high accuracy by curved face portion 19 of the working hole 15. Working this portion with high accuracy is important from the viewpoint of ensuring the accuracy of the outer ring raceway 5 (shown in
In the next process, in order to form a half portion in the axial direction (a lower half portion in
First of all, as shown in
After the primary partially finished material 10 has been set as described above, next, as shown in
As a result, it is possible to obtain the secondary partially finished material 11 in which a concave face portion 21a, which is an axial direction half portion of outer ring raceway 5, is provided in a portion close to one end in the axial direction of the inner circumferential face. When the secondary partially finished material 11 is made in this way, in the process of ironing in which while the shape of the concave face portion 21 is being straightened, it is moved to a predetermined position, and in which the concave face portion 21a, which becomes the axial direction half portion of the outer ring raceway 5, is obtained, stress of working is given only to a contact portion of the convex face portion 29 with the concave face portion 21. Accordingly, plastic working can be high accurately conducted on the concave face portion 21a, which becomes the axial direction half portion of the outer ring raceway 5, by the convex face portion 29. A shape of a portion close to one end in the axial direction (a lower half portion in
In this process, the outer ring raceway forming is conducted as follows. An outer diameter of a portion close to the other end in the axial direction of the secondary partially finished material 11 (a portion close to the upper end in
First, as shown in
As a result of this pushing work, the portion, which has not been contracted yet, is ironed by the curved face portion 35 which continuously connects the large diameter portion 33 with the small diameter portion 32. Therefore, an outer diameter of this portion is also contracted so that it can agree with an outer diameter of the outer ring 2a. At the same time, on the inner diameter side of this portion, a concave face portion 36, which becomes the other half portion in the axial direction of the outer ring raceway 5, is formed. That is, as described before, a distribution of the wall thickness in the axial direction with respect to the radial direction of the portion, the diameter of which has not been contracted yet, is made to agree with a distribution of the wall thickness of the portion concerned of the outer ring 2a to be manufactured. In this case, consideration is given to an increase in the wall thickness caused when the diameter is reduced. Therefore, when the outer diameter of the above portion is reduced so that it can agree with the outer diameter of the outer ring 2a, a shape of the cross-section on the inner circumferential face side agrees with the other half portion in the axial direction of the outer ring raceway 5. Accordingly, the concave face portion 36 described before is formed. This concave face portion 36 continues to the concave face portion 21a described before and composes the deep groove type outer ring raceway 5. In this way, the third partially finished material 12 described before is formed.
Third partially finished material 12 obtained as described above is subjected to finish working, that is, engaging grooves for engaging an outer circumferential edge portion of a sealing plate are formed at both axial end portions of the inner circumferential face. This work of forming the engaging grooves is conducted as shown in
In this case, a method of the first embodiment shown in
According to the method of the second embodiment shown in
In this connection, it is possible to execute the method shown in
Even when engaging grooves 38, 38 are formed by any method, in order to ensure the rolling fatigue life of the outer ring 2a obtained in this way, a portion of the outer ring raceway 5 is subjected to heat treatment so that the portion of the outer ring raceway 5 can be hardened, that is, quenching is conducted on the portion of the outer ring raceway 5. After the heat treatment has been completed, the outer ring 2a is combined with the inner ring 3 and balls 4, 4 so that the radial ball bearing 1 shown in
In the raceway forming process, which is the fourth and the fifth process, an outer diameter of the portion close to the other end in the axial direction (close to the lower end of
This rolling is conducted in such a manner that a portion in the circumferential direction of the secondary partially finished material 11 is pressed in the radial direction between the circumscribing roller 129 and the inscribing roller 130 which are pivotally supported in parallel to each other so that they can be relatively rotated in the opposite direction. The circumscribing roller 129 is a thick disk shape and pivotally supported under the condition that a displacement in the radial direction of the roller is suppressed. The width of the circumscribing roller 129 is larger than the width (the length in the axial direction) of the outer ring 2a to be manufactured and the outer circumferential face of the circumscribing roller 129 is cylindrical. The inscribing roller 130 is formed into a columnar shape. In one portion of the circumferential face, a working curved face portion 131 is provided, the cross-sectional shape (the generating line shape) of which is the same as that of the inner circumferential face of the outer ring 2a to be manufactured. The inscribing roller 130 is pressed to the outer circumferential face of the circumscribing roller 129 and rotated by a driving mechanism and a pressing mechanism not shown in the drawing.
The secondary partially finished material 11 is worked into the outer ring 2a as follows. Under the condition that this secondary partially finished material 11 is loosely, externally engaged with the inscribing roller 130, while this inscribing roller 130 is being pressed to the outer circumferential face of the circumscribing roller 129, this inscribing roller 130 is rotated. The secondary partially finished material 11 is rotated by the inscribing roller 130 in the same direction as that of the inscribing roller 130 together with the inscribing roller 130. While the secondary partially finished material 11 is being rotated in this way, it is pressed to the outer circumferential face of the circumscribing roller 129. Therefore, the circumscribing roller 129 is rotated together with the secondary partially finished material 11 and the inscribing roller 130 in the opposite direction to the rotating direction of the inscribing roller 130. A portion of the secondary partially finished material 11 in the circumferential direction is pressed in the radial direction between the outer circumferential faces of both rollers 129 and 130. This portion pressed in the radial direction in this way is continuously changed in the circumferential direction. As a result, a diameter of the portion close to the other end in the axial direction of the secondary partially finished material 11 is gradually expanded until it comes into contact with the outer circumferential face of the circumscribing roller 129.
After the diameter of the portion close to the other end in the axial direction of secondary partially finished material 11 has been expanded and the outer diameter of this secondary partially finished material 11 has been made to be uniform all over the length in the axial direction (except for the chamfered portion in both end edge portions), a shape of the working curved face portion 131 of the inscribing roller 130 is transferred onto the inner circumferential face of the secondary partially finished material 11. This working curved face portion 131 has a convex face portion 132, the cross-section of which is formed into an arc shape, to form the outer ring raceway 5 at the center in the axial direction. At both axial end portions in the step portions 12, 12, protrusions 133, 133 are formed which are used for working the engaging grooves to be engaged with outer circumferential edges of the sealing plate. Accordingly, under the condition that the shape of the working curved face portion 131 is transferred onto the inner circumferential face of the secondary partially finished material 11, it is possible to obtain the outer ring 2a described before which includes outer ring raceway 5 at the axially central portion on the inner circumferential face and also includes engaging grooves 134, 134 at both end portions. Therefore, according to the present embodiment, a sealing face forming process, which is the fifth process, can be simultaneously performed together with the raceway forming process which is the fourth process.
FIGS. 13 to 15 are views showing Embodiment 6 of the present invention. In this embodiment, the second process to the fifth process are simultaneously performed by rolling. In the present embodiment, working, in which the preliminary partially finished material 9 shown in
The die 122b is formed into an annular shape. An inner diameter of the die 122b is determined so that the die 122b can be internally engaged with the preliminary partially finished material 9 without forming any substantial gap. The die 122b is pivotally supported by a support portion not shown under the condition that a displacement in the radial direction is prevented. An outer diameter of the mandrel 135a is determined so that the mandrel 135a can be freely inserted into and drawn out from the preliminary partially finished material 9 and the outer ring 2a. In a portion on the outer circumferential face of the intermediate portion of the mandrel 135a and opposed to the inner circumferential face of dies 122b, the working side circumferential face 136 is provided which has a generating line shape that agrees with a generating line shape of the worked side circumferential face in a finished product state, that is, a generating line shape of the inner circumferential face of the outer ring 2a. This mandrel 135a is rotated being driven by a drive unit not shown and strongly pressed to the inner circumferential face of the die 122b by a pushing device not shown.
In order to work the preliminary partially finished material 9 described before into outer ring 2a, first, the preliminary partially finished material 9 shown in
An inclination angle α of both step faces 138, 138 with respect to an virtual plane existing in a direction perpendicular to the central axis of the preliminary partially finished material 9 is regulated in relation with an inclination angle β of step faces 138a, 138a existing in a portion corresponding to the outer ring 2a shown in
After the preliminary partially finished material 9 described above has been internally engaged in the die 122b without causing any rattling, the mandrel 135a is inserted into the preliminary partially finished material 9 as shown in
After this mandrel 135a has been inserted into the preliminary partially finished material 9, while this mandrel 135a is being rotated by the driving device and the pushing device described before, this mandrel 135a is pressed onto an inner circumferential face of the preliminary partially finished material 9. As a result, in the process shown in FIGS. 13(C) and 13(D), rolling is conducted in which a shape of the working side circumferential face 136, which is provided on the intermediate portion outer circumferential face of this mandrel 135a, is transferred onto an inner circumferential face of preliminary partially finished material 9. That is, when the working side circumferential face 136 of the mandrel 135a is pressed to the inner circumferential face of the preliminary partially finished material 9 while mandrel 135a is being rotated, metallic material composing the preliminary partially finished material 9 flows in the direction of an arrow shown in
In the process of rolling described above, the outer circumferential face of the preliminary partially finished material 9 is restricted by the die 122b all over the circumference. Therefore, the diameter of the preliminary partially finished material 9 is not expanded. Accordingly, it is possible to reduce a plastic deformation necessary when the inner circumferential face shape is formed into the shape of the outer ring 2a. Therefore, a force of the pressing working side circumferential face 136 of the mandrel 135a onto the inner circumferential face of the preliminary partially finished material 9 can be reduced. Accordingly, stress generated in the preliminary partially finished material 9 can be suppressed to be low. Each portion of the inner ring 2a, which includes the engagement groove for engaging the outer circumferential edge of the sealing ring existing on the inner circumferential faces at both axial end portions of the outer ring 2a, can be worked with high accuracy. Further, the working time can be shortened. Therefore, the manufacturing cost can be reduced. Furthermore, the circularity of the outer ring 2a obtained in this way can be enhanced. In this connection, in the case where the outer ring 2 shown in
In the preliminary partially finished material 9, inclination angles of both step faces 138, 138, which are inclined by the angle α, are decreased. Therefore, they become both step faces 138a, 138a which are inclined by the angle β. In the preliminary partially finished material 9, inclination angles of both end faces 139, 139 in the axial direction, which are inclined by angle γ, are decreased. Therefore, they become both end faces 139a, 139a in the axial direction existing in the direction of a right angle with respect to the axial direction. In the case of the present embodiment, inclination angles α and γ of the portions of the preliminary partially finished material 9 are properly regulated in the relation with the inclination angle of each portion of outer ring 2a after the completion. Therefore, at the time of rolling, a force given to the mandrel 135a can be suppressed to be low. Accordingly, the durability of mandrel 135a and the working accuracy of the outer ring 2a obtained can be enhanced. That is, since the preliminary partially finished material 9 is given inclination angles α and γ described before, metallic material smoothly flows inside in the radial direction at the time of rolling. Therefore, a force given to the mandrel 135a can be reduced.
Next, referring to Embodiments 7 to 12, a method of forming an inner ring of the present invention will be explained below.
FIGS. 16 to 20 are views showing Embodiment 7 of the present invention. In the same manner as that of Embodiment 1 described before, in the present embodiment, a cylindrical high accurate material 8 (shown in
In the present embodiment, the high accurate material 8 shown in
In order to form the high accurate material 8 into the preliminary partially finished material 9, operation is conducted as follows. An outer circumferential face of this high accurate material 8 is internally engaged in an inner circumferential face of a holding die not shown. An inner circumferential face of this high accurate material 8 is externally engaged with a core. In this state, a forward end face of a punch not shown is pressed all over the circumference to outer diameter side half portions on both axially end faces of this high accurate material 8. As a result, the outer diameter side half portions on both axially end faces of this high accurate material 8 are recessed in the axial direction. Therefore, the preliminary partially finished material 9 having step portions 213, 213 in the portions concerned can be obtained. At this time, metal, which has flowed inside in the radial direction when both step portions 213, 213 are formed, can be absorbed when the inner diameter side half portions of both axial end portions are protruded in the axial direction. In this connection, an inner diameter of the preliminary partially finished material 9, which is made in this way, is substantially the same as an inner diameter of the inner ring 3a to be manufactured. It is not necessary that an inner diameter of the preliminary partially finished material 9, which is made in this way, is strictly the same as an inner diameter of the inner ring 3a to be manufactured.
Pipe contraction working is conducted on the preliminary partially finished material 9 as follows. An outer diameter of a portion (an upper end portion in
First, as shown in
In this connection, in the embodiment shown in the drawing, when the convex face portion 220 is formed in a portion of axially intermediate portion of the punch 217, a concave face portion 221, the cross-section of which is arcuate, is formed in a portion close to one end of the inner circumferential face of the partially finished material 10 all over the circumference. The punch 217 forms this concave face portion 221 in an initial stage of working in which the preliminary partially finished material 9 is worked into the partially finished material 10. Accordingly, in the process in which the outer diameter is contracted so that the outer diameter of the portion of the preliminary partially finished material 9 can be contacted and the preliminary partially finished material 9 can be formed into partially finished material 10, working stress is given only to a contact portion between the concave face portion 219 and an outer circumferential face of the preliminary partially finished martial 9 except for the initial stage described before. Accordingly, the outer circumferential face of the partially finished material 10 can be plastically deformed by the convex face portion 219 of the working hole 215 with high accuracy. High accurate working of this portion is important for ensuring the accuracy of the inner ring raceway 6 (shown in
In the next process, in order to make a distribution in the axial direction of the wall thickness with respect to the radial direction of a portion corresponding to the other half portion (lower half portion of
First, as shown in
After the partially finished material 10 has been set as described above, as shown in
As a result, in a portion close to one end in the axial direction of the inner circumferential face (a portion on the lower side in
In the next process, inner ring raceway forming is conducted in which an inner diameter of a portion close to the other end (on a lower end side in
First, as shown in
As a result of the above pushing work, the contracted portion is ironed by the curved face portion 236 which continuously connects the small diameter portion 233 with the large diameter portion 234. Therefore, an inner diameter of this portion can be expanded into a state in which the inner diameter agrees with the diameter of the inner ring 3a. At the same time, on the outer diameter side of this portion, the concave face portion 237, which becomes the other half portion in the axial direction of the inner ring raceway 6, is formed. That is, as described before, a distribution in the axial direction of the wall thickness with respect to the radial direction in the contracted portion agrees with the distribution of the portion concerned of the inner ring 3a to be made. However, the wall thickness is a little large when consideration is given to a decrease in the wall thickness caused when the diameter is expanded. Therefore, when the inner diameter of the portion is expanded to a state in which the inner diameter of the portion agrees with the inner diameter of the inner ring 3a, a shape of the cross-section on the outer circumferential face side agrees with the other half portion in the axial direction of the inner ring raceway 6. Accordingly, the concave face portion 237 is formed. The concave face portion 237 (the second raceway curved face) composed as described above continues to the concave face portion 238 (the first raceway curved face), which is formed by the convex face portion 219 of the working hole 215 provided in the die 214, so that the deep groove type inner ring raceway 6 can be composed. In this way, the third partially finished material 12 is formed.
Finish working is conducted on the third partially finished material 12 obtained in this way and a pair of sealing step portions, with which an inner circumferential edge portion of the tight-sealing plate comes into slide contact or to which an inner circumferential edge portion of the tight-sealing plate is opposed, are formed. Working of this engaging groove is conducted as shown in
The first example method shown in
When step portions 240, 240 for sealing are formed, instead of the process shown in
In this connection, after the method of the seventh embodiment shown in
Even when step portions 240, 240 for sealing are formed by any method, in order to ensure the rolling fatigue life of inner ring 3a obtained in this way, a portion of the inner ring raceway 6 is subjected to heat treatment so that the portion of the inner ring raceway 6 can be hardened, that is, quenching is conducted on the portion of the inner ring raceway 6. After the heat treatment has been completed, the inner ring 3a is combined with the outer ring 2 and the balls 4, 4 so that the radial ball bearing 1 shown in
Referring to FIGS. 22 to 30, Embodiments 9 to 12 of the present invention will be explained below.
FIGS. 22 to 23 are views showing Embodiment 9 of the present invention. In the present invention, raceway forming and sealing face forming, which are the fourth and the fifth process in Embodiment 7 described before, are simultaneously conducted.
In the raceway ring forming process, which is the fourth and the fifth process, inner ring raceway forming is conducted as follows. An inner diameter of a portion close to the other end in the axial direction of secondary partially finished material 11 (a portion closer to the lower end in
This rolling work is conducted in such a manner that a portion in the circumferential direction of the secondary partially finished material 11 is pushed in the radial direction between the circumscribing roller 329c and the inscribing roller 330a, which are arranged in parallel with each other and pivotally supported so that they can be relatively rotated in the opposite directions to each other. The circumscribing roller 329c is a thick disk shape and pivotally supported under the condition that a displacement in the radial direction of the roller is suppressed. The width of the circumscribing roller 329c is larger than the width (the length in the axial direction) of the inner ring 3a to be manufactured. In an axially intermediate portion of the outer circumferential face of the circumscribing roller 329c, a working curved face portion 331a is provided, the cross-sectional shape (the generating line shape) of which is the same as that of the outer circumferential face of inner ring 3a to be manufactured. On the other hand, an inscribing roller 330a is formed into a columnar shape and the outer circumferential face is formed into a simple cylindrical face, that is, the outer circumferential face is parallel with the rotary center. The inscribing roller 330a is pressed to the inner circumferential face of the circumscribing roller 329c and rotated by a driving mechanism and a pressing mechanism not shown in the drawing.
In order to work the secondary partially finished material 11 into the inner ring 3a described before, under the condition that this secondary partially finished material 11 is loosely, externally engaged with the inscribing roller 330a, this inscribing roller 330a is rotated while this inscribing roller 330a is being pressed to the outer circumferential face of the circumscribing roller 329c. The secondary partially finished material 11 is rotated by the inscribing roller 330a in the same direction as that of the inscribing roller 330a together with the inscribing roller 330a. While the secondary partially finished material 11 is being rotated in this way, it is pressed to the outer circumferential face of the circumscribing roller 329c. Therefore, the circumscribing roller 329c is rotated together with the secondary partially finished material 11 and the inscribing roller 330a in the opposite direction to the rotating direction of the inscribing roller 330a. A portion of the secondary partially finished material 11 in the circumferential direction is pressed in the radial direction between the outer circumferential faces of both rollers 329c and 330a. This portion pressed in the radial direction in this way is continuously changed in the circumferential direction. As a result, a diameter of the portion close to the other end in the axial direction of the secondary partially finished material 11 is gradually expanded until it comes into contact with the outer circumferential face of circumscribing roller 329c.
After the diameter of the portion close to the other end in the axial direction of the secondary partially finished material 11 has been expanded and the inner diameter of this secondary partially finished material 11 has been made to be uniform all over the length in the axial direction (except for the chamfered portions in both end edge portions), a shape of the working curved face portion 331a of the circumscribing roller 329c is transferred onto the outer circumferential face of the secondary partially finished material 11. This working curved face portion 331a has a convex face portion 332a, the cross-section of which is formed into an arc shape, to form the inner ring raceway 6 at the center in the axial direction. At both axial end portions, working faces are formed which are used for working sealing faces by which step portions 312a, 312a are made to come into slide contact with inner circumferential edges of the tight-sealing plate or opposed to inner circumferential edges of the tight-sealing plate. Accordingly, under the condition that the shape of the working curved face portion 331a is transferred onto the inner circumferential face of the secondary partially finished material 11, it is possible to obtain the inner ring 3a described before which includes the inner ring raceway 6 at the axially central portion on the inner circumferential face and also includes sealing faces at both end portions.
A central axis of this mandrel 335 and rotary central axes of both circumscribing rollers 329e, 329e are arranged on a single virtual plane in parallel with each other. An outer diameter of the mandrel 335 agrees with an inner diameter of the inner ring 3a to be worked. In the present embodiment, the secondary partially finished material 11 is formed so that an inner diameter of a portion close to one end (on the lower side of
When rolling work is conducted in order to work the secondary partially finished material 11 into the outer ring 3a, while the secondary partially finished material 11 is being externally engaged with the mandrel 335, both circumscribing rollers 329e, 329e are pushed to each other and rotated so that both rollers can come close to each other. As a result, an outer diameter of a portion of the secondary partially finished material 11 is contracted and the inner ring raceway 6 and a sealing face are formed on the outer circumferential face. The constitution and action of other portions are the same as those of Embodiments 9 and 10 described before. Therefore, the duplicated drawings and explanations are omitted here.
FIGS. 28 to 30 are views showing Embodiment 12 of the present invention. In the present embodiment, the second process to the fifth process are simultaneously conducted by means of rolling work. In the case of the present embodiment, the working shown in
Therefore, in the case of the present embodiment, the preliminary partially finished material 9 shown in
Next, referring to Embodiments 13 to 24, a manufacturing method of a high accurate ring preferably used for manufacturing the above raceway ring will be explained in detail below. In this connection, of course, this high accurate ring is used for the above raceway ring. Further, this high accurate ring can be used for a high accurate mechanical element such as a rocker arm of an internal combustion engine.
The billet 413 obtained in this way is worked into the primary partially finished material 414 shown in
Next, a central portion of the primary partially finished material 414 is compressed in the axial direction. Metal, which has been pushed out by this compression, is released to a peripheral portion by extrusion working. Due to the foregoing, the second partially finished cylindrical material 415 having a bottom, the size in the axial direction of which is larger than the size of the primary partially finished material 414, can be obtained as shown in
An outer diameter of the punch is substantially the same as an inner diameter of the high accurate ring 8a. In this case, it is unnecessary that the outer diameter of the punch is strictly the same as the inner diameter of the high accurate ring 8a. When this punch is inserted into the second receiving hole, a large diameter portion formed in a base portion of the punch is internally engaged with a neighborhood of the opening portion of the second receiving hole, so that the central axes of the punch and the second receiving hole agree with each other. As a result of the above rear extrusion working, the thickness of the axially central portion of the primary partially finished material 414 is reduced. At the same time, excess metal is released to a portion on the outer diameter side. Therefore, a size of this portion on the outer diameter side in the axial direction is increased. In this way, the secondary partially finished material 415 can be provided. This secondary partially finished material 415 has the same outer diameter as that of the high accurate ring 8a to be obtained, the substantially same inner diameter as that of this high accurate ring 8a and the length in the axial direction larger than that of this high accurate ring 8a.
Next, the secondary partially finished material 415 obtained in this way is subjected to piercing working by which a bottom portion of the secondary partially finished material 415 is pierced. At this time, while an outer circumferential face and a bottom portion outer diameter portion of the secondary partially finished material 415 are being held by the third receiving die, a punch is pushed inside this secondary partially finished material 415. The bottom portion of this secondary partially finished material 415 is sheared between the forward end face of the punch and the third receiving die. In this way, the third partially finished cylindrical material 416 shown in
Next, inner diameter excess thickness extrusion working is conducted in which a size in the axial direction of the third partially finished material 416 is accurately reduced to a predetermined value. This excess thickness extrusion working is conducted as follows. As shown in
At the time of the inner diameter excess thickness extrusion working conducted as described above, according to the excess metal generated when the size in the axial direction of the third partially finished material 416 is contracted, the inner circumferential face of the third partially finished material 416 swells out being formed into a convex face. Therefore, the fourth partially finished material 421 shown in
Next, the fourth partially finished material 421 obtained in this way is subjected to inner diameter ironing work. In this inner diameter ironing work, while an outer circumferential face of the fourth partially finished material 421 is being held by a die so that the outer diameter of the fourth partially finished material 421 can not be expanded, an ironing jig (a metallic die) is pushed into a central hole 422 of this fourth partially finished material 421. An outer diameter of this ironing jig agrees with inner diameter R8a of the high accurate ring 8a to be obtained. A central axis of this ironing jig is made to strictly agree with a central axis of the above die. In the above inner diameter ironing work, when a portion close to the inner diameter of the fourth partially finished material 421 is ironed by the above ironing jig from one end to the other end in the axial direction, that is, from the top to the bottom in
After the fifth partially finished material 424 described above has been obtained, excess thickness portion 423 described above is removed by piercing working. In this piercing working, a punch, the outer diameter of which agrees with inner diameter R22 (=inner diameter R8a of the high accurate ring 8a) of central hole 422a of the fifth partially finished material 424 is inserted into the central hole 422a. Between a forward end face of this punch and a receiving die, a base end portion (an outer circumferential edge portion) of the excess thickness portion 423 is sheared. By this piercing working, the high accurate cylindrical ring 8a, the volume of which is substantially the same as that of the inner ring 3a, can be obtained.
This high accurate ring 8a is formed into the inner ring 3a composing a radial ball bearing by the process shown in
Next,
Therefore, in the present embodiment, in the case where the third partially finished material 416 is compressed in the axial direction between forward end faces of punches 418a, 418b which are arranged concentrically with each other according to an engagement in which a protrusion and a recess are engaged with each other, the third partially finished material 416 is tightly, externally engaged with a guide pin portion 425 provided at a forward end face central portion of one punch 418a (a lower punch shown in
Excess metal, which has swelled outside in the radial direction, is collected at one end portion in the axial direction by ironing work being formed into a flange-shaped excess thickness portion and removed. Alternatively, it is removed by shaving working. In this case, a working method of removing the excess thickness portion is the same as those of Embodiments 13 and 33 except that the inside and the outside in the radial direction is inverted. In this connection, in the case where excess thickness portion 423 is formed at an end portion in the axial direction as shown in
Next, this disk-shaped material 426 is subjected to piercing working, by which a central portion is punched out, and trimming work by which an outer circumferential portion is removed. In this way, the primary partially finished material 427 shown in
Next, the thus obtained primary partially finished material 427 is subjected to inversion work in which a cross-section of the primary partially finished material 427 is twisted by the angle 90° so that the inner diameter side can be expanded and the outer diameter side can be contracted. Due to the foregoing, the secondary partially finished material 428, the shape of which is cylindrical, shown in
As shown in
The above inversion working is conducted as follows. First, as shown in
As shown in FIGS. 35(D) to 35(F), thus obtained secondary partially finished material 428 is subjected to the inner diameter excess thickness extrusion working, the inner diameter ironing working and the piercing working shown in FIGS. 31(E) to 31(G) in Embodiment 13. In this way, high accurate ring 8a for inner ring 3a (shown in
This high accurate ring 8a becomes the inner ring 3a composing a radial ball bearing by the process shown in
This high accurate ring 8a becomes the inner ring 3a composing a radial ball bearing by the process shown in
In this connection, concerning Embodiments 16 and 17, when the excess thickness extrusion working is conducted so that the excess metal can be swelled onto the outer diameter side in the same manner as that of Embodiment 15 shown in
FIGS. 38 to 39 are views showing Embodiment 18 of the present invention. In this embodiment, first, a long wire rod is cut into a predetermined length so as to obtain a billet (columnar material) 521 shown in
Thus obtained billet 521 is subjected to upsetting working by which the billet 521 is compressed in the axial direction. In this way, the billet 521 is formed into the disk-shaped partially finished material 522 shown in
In the present embodiment, after the disk-shaped partially finished material 522 has been formed or simultaneously when the disk-shaped partially finished material 522 is formed, at the center on both sides in the axial direction of the disk-shaped partially finished material 522, circular recess portions 523, 523, which are shown in
After the second disk-shaped partially finished material 524 has been formed as described above, next, circular hole 525 is formed in the central portion of the second disk-shaped partially finished material 524. This circular hole 525 is formed by punching as follows. Under the condition that this second disk-shaped partially finished material 524 is set in a holding recess portion of a receiving die, a punch arranged concentrically with this holding recess portion is made to collide with a central portion of the second disk-shaped partially finished material 524 and this central portion is pushed out into a punching hole formed in the central portion of the holding recess portion. Since an outer diameter of the punch is larger than diameter D23 of both recess portions 523, 523, the central portion of the second disk-shaped partially finished material 524 including entire both recess portions 523, 523 is punched out. Therefore, a ring-shaped partially finished material 526 shown in
After this ring-shaped partially finished material 526 has been formed, inversion working is conducted as shown in
According to the inversion work described above, the portion on the inner diameter side of the ring-shaped partially finished material 526 is expanded and the thickness is decreased and the portion on the outer diameter side of ring-shaped partially finished material 526 is compressed and the thickness is increased. In the present embodiment, the thickness in the axial direction of the ring-shaped partially finished material 526 on the inner diameter side is large and the thickness in the axial direction of the ring-shaped partially finished material 526 on the outer diameter side is small. Therefore, the thickness in the radial direction of the high accurate ring 8, which is obtained when the aforementioned inversion working has been completed, becomes uniform with respect to the radial direction except for chamfered portions in both end edge portions. That is, when the inversion working has been completed, the cylindrical high accurate ring 8 can be provided, the inner diameter, the outer diameter and the length in the axial direction of which are equal to the regulated values. Therefore, a difference between inner diameter R19 of the small diameter portion 519 and outer diameter D17 of the forward half portion of punch 517 is made to be twice as large as thickness T8 (shown in
In the present embodiment, as shown in
The constitution and action of other portions are the same as those of Embodiment 18 described before.
This sizing working is conducted as follows. For example, as shown in
In this connection, in the present embodiment, as shown in
The constitution and action of other portions are the same as those of Embodiment 18 or 19 described before.
In the case of the present embodiment, when the preliminary partially finished material 532 shown in
The fixing block 533 supports and fixes a frame of a press forming machine arranged on a floor of a factory. The die 534 is elastically supported at a position above the fixing block 533 by a plurality of elastic members 538, 538 such as a compression coil spring. Accordingly, when working is not conducted, the die 534 floats above the fixing block 533 as shown in
A position of this counter punch 535 in the vertical direction is regulated as follows. When working is not conducted, as shown in
The ring punch 536 is elastically supported by a plurality of elastic members 538a, 538a such as a compression coil spring at a lower portion of a ram 541 of a press forming machine provided in an upper portion of the die 534, wherein the ring punch 536 is arranged concentrically with die 534. Accordingly, when working is not conducted, the ring punch 536 hangs from the ram 541 as shown in
The punch 537 is inserted into the upper side central hole 542 so that the punch 537 can be elevated with respect to the ring punch 536. In the present embodiment, the pinch 537 is fixed to the ram 541 and according to an elevation of the ring punch 536 with respect to this ram 541, the punch 537 and the ring punch 536 can be relatively elevated. A position in the vertical direction of this punch 537 is regulated as follows. When working is not conducted, as shown in
The preliminary partially finished material 532 shown in
In the case of the present embodiment, after the disk-shaped partially finished material 522a has been formed as described above, while an outer circumferential edge of this disk-shaped partially finished material 522a is being restricted so that the outer diameter can not be expanded, a circular recess portion 523a shown in
Therefore, as shown in
Since the present embodiment adopts the above constitution, portions, which are on both axially end faces of the billet 521, do not remain in a portion of the high accurate ring 8 thus obtained. Therefore, the present embodiment is advantageous from the viewpoint of obtaining a product of high quality at a low manufacturing cost.
The constitution and action of other portions are the same as those of Embodiments 18 to 20 described above.
In the present embodiment, for example, in the same manner as that of the first half portion (the process of
In the case of the present embodiment, the recess portion 523a is formed only on one side of the disk-shaped partially finished material 522a. When a central portion on one side of this disk-shaped partially finished material 522a is pressed in order to form this recess portion 523, as shown in
As shown in
Since the present embodiment is composed as described above, when the ring-shaped partially finished material 526a is subjected to inversion working to form the high accurate ring 8 described above, a degree of working (a drawing rate) of the inner circumferential edge portion, the diameter of which is expanded, can be suppressed low. Therefore, it is possible to prevent the generation of harmful deformations or cracks in this inner circumferential edge portion. Accordingly, it is possible to manufacture the high accurate ring 8, the width in the axial direction of which is relatively large, by the high yield. Referring to
First, in order to understandingly explain an operational effect of the present embodiment, consideration is given to the ring-shaped partially finished material 526b shown in
As described in Embodiments 18 to 21, in the case of the ring-shaped partially finished material 526 shown in
FIGS. 48 to 51 are views showing Embodiment 23 of the present invention. In this connection, in the technical field of press forming such as plastic working and punching including cold forging, when shapes before and after the completion of working are known, it is easy (obvious) to understand a shape and structure of a metallic die to be used for plastic working. Accordingly, a shape and structure of some metallic die is omitted in the drawing. Therefore, in the following process, a shape of a workpiece is mainly explained below. In order for a state of progress of working to be understood easily,
In the present embodiment, first of all, a long wire rod is cut by a predetermined length and a billet (columnar material) 613 shown in
When the billet 613 obtained in this way is subjected to upsetting working in which the billet 613 is compressed in the axial direction by cold working, both axially end faces of the billet 613 are straightened and the billet 613 is formed into the (first) preliminary partially finished material 616, the shape of which is a beer-barrel shape as shown in
Concerning the thickness in the axial direction of this second preliminary partially finished material 617, thickness T18 of the central boss portion 618 is the largest. Thickness t1, t2 of the flange portion 619 is smaller than thickness T18 of the boss portion 618 (T18>t1>t2). A cross-sectional shape of this flange portion 619 is a wedge shape. Thickness t1, t2 of this flange portion 619 is gradually changed in the radial direction. Concerning thickness t1, t2 of this flange portion 619, thickness t1 of the inner circumferential portion is large and thickness t2 of the outer circumferential portion is small. The flange portion 619 is a portion to be formed into the second high accurate ring 615 for making outer ring 3a (shown in
When upsetting working is conducted to form the second preliminary partially finished material 617, the preliminary partially finished material 616 is compressed in the axial direction between a pair of metallic dies, the inner face shape of which agrees with an outer face shape of the second preliminary partially finished material 617. That is, the preliminary partially finished material 616 is set in a receiving die having a circular hole having a bottom, the shape of which is formed in such a manner that the inner diameter is the same as the outer diameter D17 of the second preliminary partially finished material 617 and a shape of the bottom face agrees with a shape of one side face in the axial direction (lower face of
When the second upsetting working for crushing the central portion of the boss portion 618 in the axial direction is conducted on this second preliminary partially finished material 617, the third preliminary partially finished material 620 shown in
In the case where the second preliminary partially finished material 617 is formed into the third preliminary partially finished material 620, the flange portion 619 of this second preliminary partially finished material 617 is held between the receiving die and the holding die. At the same time, under the condition that a forward end face of a holding cylinder of the punch unit is fixed at a proper position, the punch of this punch unit is pressed to a forward end portion of boss portion 618. This pressing work is conducted until a portion of this boss portion 618 reaches a forward end face of the holding cylinder and metallic material can not flow anymore, that is, the punch can not be displaced anymore. As a result, the thickness in the axial direction of the central portion of the boss portion 618 is reduced and the thickness in the axial direction of a portion on the outer diameter side of the boss portion 618 is increased. Therefore, in this portion on the outer diameter side of the boss portion 618, a cylindrical portion 621, the size in the axial direction of which is regulated at a predetermined value, is formed. Concerning the third preliminary partially finished material 620 obtained in this way, length L21 from a base end face (an upper face shown in
After the third preliminary partially finished material 620 has been formed in the manner described above, as shown in
As shown in
The first high accurate ring 614 and the secondary partially finished material 627 obtained in this way are worked as follows. The first high accurate ring 614 is formed into the inner ring 3a, for example, by the above process shown in
In the process in which the secondary partially finished material 627 is formed into the second high accurate ring 615, first, as shown in FIGS. 49(A) and 50, while this secondary partially finished material 627 is being tightly, internally engaged in a circular hole 630 of a die 629, this secondary partially finished material 627 is strongly pressed between forward end faces of a pair of punches 631, 631, that is, so-called sizing working is conducted. Forward end faces of both punches 631, 631 are formed into conical concave faces which tightly come into contact with both sides in the axial direction of the secondary partially finished material 627. While both punches 631, 631, the forward end faces of which are formed into the above shape, are compressing the secondary partially finished material 627 in the axial direction, a distance between the forward end faces is reduced to a proper distance. In this way, the thickness of the secondary partially finished material 627 is made to be a proper value. At this time, excess metal, which has flowed when the thickness of the secondary partially finished material 627 is made to be the proper value, collects in an inner circumferential edge portion of the secondary partially finished material 627. Accordingly, when the circular hole 632 is formed in a central portion of secondary partially finished material 627, which has been subjected to sizing working, by punching working (piercing working) as shown in
After the fourth preliminary partially finished material 633 has been formed in this way, inversion working is conducted in which a portion of the fourth preliminary partially finished material 633 on the outer diameter side is contracted inward in the radial direction and a portion on the inner diameter side is expanded outward in the radial direction so that a direction of the cross-section can be changed by the angle 90° as shown in FIGS. 49(B) and 49(C). This inversion working is conducted in such a manner that the fourth preliminary partially finished material 633 is pushed into the cylindrical die 634 by the punch 635 as shown in
According to the inversion working described above, a portion on the inner diameter side of the fourth preliminary partially finished material 633 is expanded and the thickness is decreased and a portion on the outer diameter side of the fourth preliminary partially finished material 633 is compressed and the thickness is increased. On the other hand, in the present embodiment, the thickness in the axial direction of the fourth preliminary partially finished material 633 on the inner diameter side is large and the thickness in the axial direction of the fourth preliminary partially finished material 633 on the outer diameter side is small. Therefore, the thickness in the radial direction of the second high accurate ring 615, which is obtained when the aforementioned inversion working has been completed, becomes uniform with respect to the radial direction of the second high accurate ring 615 except for chamfered portions in both end edge portions. That is, when the inversion working has been completed, the cylindrical second high accurate ring 615 can be provided, the inner diameter, the outer diameter and the length in the axial direction of which are equal to the regulated values. Therefore, a difference between inner diameter R37 of the small diameter portion 637 and outer diameter D35 of the forward half portion of the punch 635 is made to be twice as large as thickness T15 (shown in
In the case of the present embodiment, when upsetting working is conducted on this second preliminary partially finished material 639 so as to compress it in the axial direction, it is possible to obtain the disk-shaped third preliminary partially finished material 641 shown in
Upsetting working for forming the third preliminary partially finished material 641 is conducted basically in the same manner as that of Embodiment 23 described before in such a manner that the second preliminary partially finished material 639 is compressed in the axial direction between a pair of metallic dies having an inner face shape agreeing with an outer face shape of the third preliminary partially finished material 641. Especially, in the case of the present embodiment, under the condition that both metallic dies are made to come close to each other until an interval between both metallic dies can be a predetermined value, a punch, which is arranged being capable of moving in the axial direction with respect to the metallic die, is strongly pressed to a central portion of the third preliminary partially finished material 641, which is a workpiece, so as to reduce the thickness of this central portion. Then, the thickness in the axial direction of the central portion of boss portion 642 is reduced and metallic material is made to flow from this central portion and this metallic material is completely filled between both metallic dies. As a result, length L42 in the axial direction of the boss portion 642 and the thickness in the axial direction of the flange portion 619 can become predetermined values. The reason is that both metallic dies are stopped when a distance between both metallic dies has become a predetermined value. The thickness in the radial direction of each portion in the boss portion 642 is strictly regulated at ½ of a difference between the inner diameter of both metallic dies and the outer diameter of the punch (or a portion of the metallic die). To sum up, a volumetric error of the second preliminary partially finished material 639 is compensated when the thickness of the partitioning plate portion 643 of axially intermediate portion of the boss portion 642 is made different.
After the third preliminary partially finished material 641 has been formed as described above, as shown in
As shown in
The first high accurate ring 647 and the secondary partially finished material 627 are obtained in this way. This first high accurate ring 647 is formed into an inner ring 3a, for example, by the process shown in
As described above, the present invention, which is related to a high accurate ring, is characterized in that a pair of high accurate rings for manufacturing an inner and an outer ring are manufactured with high efficiency. A working method in which the thus obtained high accurate ring is formed into an inner or an outer ring is not particularly limited.
The present invention is explained above in detail referring to the specific embodiments. However, it is obvious that variations may be made by those skilled in the art without departing from the scope and spirit of the present invention.
The present application is based on the following applications and the contents of the applications are taken in here.
Japanese Patent Application (No. 2004-275835) filed on Sep. 22, 2004
Japanese Patent Application (No. 2004-282970) filed on Sep. 29, 2004
Japanese Patent Application (No. 2004-285793) filed on Sep. 30, 2004
Japanese Patent Application (No. 2004-285794) filed on Sep. 30, 2004
Japanese Patent Application (No. 2005-165540) filed on Jun. 6, 2005
Japanese Patent Application (No. 2005-166450) filed on Jun. 7, 2005
Japanese Patent Application (No. 2005-170344) filed on Jun. 10, 2005
| Number | Date | Country | Kind |
|---|---|---|---|
| 2004-275835 | Sep 2004 | JP | national |
| 2004-282970 | Sep 2004 | JP | national |
| 2004-285793 | Sep 2004 | JP | national |
| 2004-285794 | Sep 2004 | JP | national |
| 2004-289566 | Oct 2004 | JP | national |
| 2004-351816 | Dec 2004 | JP | national |
| 2005-165540 | Jun 2005 | JP | national |
| 2005-166450 | Jun 2005 | JP | national |
| 2005-170344 | Jun 2005 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP05/17297 | 9/20/2005 | WO | 3/22/2007 |
