Patent Application
20190022818
The present invention relates to a working method for a workpiece, the working method including deburring and polishing the workpiece while rotating a brush-like grinding wheel, using a force generated by a relative motion of the brush-like grinding wheel and the workpiece as a driving force, and a polishing machine brush and a tool holder used for the working method.
A carrier is known as one of power transmission mechanisms in machine tools such as lathes and grinders (for example, Patent Literature 1). This is intended to transmit a driving force of a rotating object to an object to be rotated by connecting and fixing the rotating object and the object to be rotated by the carrier.
A lathe is a machine tool that cuts, polishes, and deburrs the workpiece (hereinafter may also be referred to as “work”) by bringing the tool in contact with the workpiece while rotating the workpiece. In lathe working, the tool is fixed to a tool grasping member and is not rotated. For this reason, a rotary-bite is known as a technique of rotating a tool to prevent the tool from melting due to frictional heat (for example, Patent Literature 2). This is a technique of rotating the tool by transmitting a rotational driving force of the workpiece to the tool by frictional resistance, thereby releasing heat of the tool.
In typical lathe working by NC control, a tool provided a cutting bite is brought in contact with a workpiece while moving the position of the tool in a state where the workpiece is rotated at a fixed position, thereby cutting the workpiece into a predetermined shape. In a deburring process after the lathe working, it is conceivable to perform the deburring by NC controlling a tool provided a polishing brush for deburring in place of the cutting tool and to bring the polishing brush in contact with the workpiece while rotating the workpiece. However, there has been a problem, in a machine tool such as a lathe not having power to rotate a tool, in the case of bringing a brush in contact with a rotating workpiece, the same portion of the brush remains in contact with the workpiece, and thus deburring and polishing effects cannot be sufficiently obtained. In addition, there has been a problem that only a part of the brush is extremely worn and the life of the brush becomes short.
The present invention has been made in view of the above problems. That is, an object of the present invention is to provide a working method capable of efficiently deburring and polishing a workpiece, and making the life of an in-use brush long, in a machine tool not having power to directly rotate a tool and capable of working the workpiece by bringing the tool and the workpiece in contact with each other while causing the tool and the workpiece to perform a relative motion.
The present invention relates to a working method for a workpiece, the working method comprising: rotating a brush-like grinding wheel by causing the brush-like grinding wheel and the workpiece to perform a relative motion while bringing the brush-like grinding wheel and the workpiece in contact with each other in a machine tool not having power to rotate a tool.
The present invention further preferable that a portion to which a driving force is transmitted by coming in contact with the workpiece and a portion where a deburring function occurs by coming in contact with an edge portion of the workpiece are different on a tip end surface of the brush-like grinding wheel.
The present invention further preferable that the relative motion is a motion of the workpiece.
The present invention further preferable that the motion of the workpiece is a rotary motion.
The present invention further preferable that rotating the brush-like grinding wheel in the same direction as a rotating direction of the workpiece by bringing the brush-like grinding wheel in contact with the workpiece from an end surface of the workpiece, the end surface being orthogonal to an axis of rotation of the workpiece.
The present invention further preferable that rotating the brush-like grinding wheel in an opposite direction to a rotating direction of the workpiece by bringing the brush-like grinding wheel in contact with the workpiece from an end surface of the workpiece, the end surface being orthogonal to an axis of rotation of the workpiece.
The present invention further preferable that bringing the brush-like grinding wheel in contact with the workpiece such that a contact surface of the brush-like grinding wheel with the workpiece becomes asymmetrical to an axis of symmetry, in a case where a straight line passing through a rotation center on the tip end surface of the brush-like grinding wheel and parallel to a direction of a force received by the brush-like grinding wheel from the workpiece is defined as the axis of symmetry.
The present invention further preferable that the motion of the workpiece is a linear motion.
The present invention further preferable that the relative motion is an orbital motion of the brush-like grinding wheel.
The present invention further preferable that the relative motion is a linear motion of the brush-like grinding wheel.
The present invention relates to a polishing machine brush comprising: a brush-like grinding wheel including linear grinding materials and a holder that holds the linear grinding materials; a grasping member that grasps the brush-like grinding wheel in a rotatable state by supporting a rear end side of the holder; and a fixing jig connected with the grasping member and used for fixing the grasping member to a machine tool.
The present invention relates to a tool holder comprising: a grasping member that grasps a tool in a rotatable state; and a fixing jig for fixing the grasping member to a machine tool, wherein the fixing jig includes an axial position adjustment member and a fixed member to be fixed to the machine tool, and the grasping member is connected with the axial position adjustment member, the axial position adjustment member is connected with the fixed member via a connection part, the axial position adjustment member is rotatable about the connection part as an axis, and a position of an axis of rotation of a tool in contact with a workpiece is adjustable by the axial position adjustment member.
According to the working method of the present invention, a workpiece is worked while rotating a brush-like grinding wheel, using a force generated by a relative motion of the workpiece and the brush-like grinding wheel as a driving force, whereby a contact point between the brush-like grinding wheel and the workpiece is not fixed, and deburring and polishing effects can be sufficiently obtained. Further, it can be prevented that only a part of a brush is extremely worn, and the life of the brush can be elongated.
Hereinafter, embodiments of the present invention will be described with reference to the drawings, but embodiments are not limited to the following embodiments unless contrary to the gist of the present invention. Note that, in the following embodiments, common elements are denoted by the same reference numerals, and redundant description is omitted as appropriate.
The brush-like grinding wheel 1 has a structure in which a base end side of a plurality of the linear grinding materials 2 is held by the cylindrical holder 3. The linear grinding materials 2 are not particularly limited as long as the materials are capable of polishing a workpiece, that is, the materials have higher hardness and brittleness than the workpiece, and can be appropriately selected according to the workpiece, a purpose of working, or the like. Specifically, an example of the linear grinding materials 2 includes materials obtained by impregnating an aggregate yarn in which long fiber such as long alumina fiber, long glass fiber, long silicon carbide fiber, or long boron fiber is aggregated with a binder resin such as a silicone resin, an urethane resin, an epoxy resin, a phenol resin, a polyimide resin, or an unsaturated polyester resin, and curing the binder resin. As the long fiber forming the aggregate yarn, the long alumina fiber or the long silicon carbide fiber is favorable in the case of polishing an iron-based metal and a non-ferrous metal because the aforementioned fiber is excellent in abrasiveness to the metals. Note that the aggregate yarn may be formed using two or more kinds of the long fiber.
One end of the cylindrical holder 3 in an axial direction is open. As illustrated in
A spindle 5 is provided inside the holder 3 to extend along an axis of rotation from the end portion on the opposite side of the opening side. As illustrated in
Further, in the case of bringing the linear grinding materials 2 in contact with the workpiece 20, escape of the linear grinding materials 2 in an inner wall-side direction of the holder 3 and in a spindle 5-side direction is restricted by the inner wall of the holder 3 and the spindle 5. Therefore, a difference in flexural rigidity less easily occurs between the inner wall side of the holder 3 and the spindle 5 side in the linear grinding materials 2. As a result, a difference in the degree of abrasion less easily occurs between the inner wall side of the holder 3 and the spindle 5 side in the linear grinding materials 2, and the accuracy of deburring and polishing work tends to improve.
A fitting groove is provided in an approximate central portion in the holder 3 when the end portion on the opposite side of the opening side in the holder 3 is viewed from the axial direction, and one end of the grasped member 6 is fit in the fitting groove. A female screw groove is provided in an end portion of the grasped member 6 on an opposite side of the fit portion with the holder 3. The grasping member 7 rotatably grasps the brush-like grinding wheel 1 as the grasped member 6 is inserted into a shaft insertion hole provided in the grasping member 7 and the female screw groove in the grasped member 6 is screwed with a bolt. Note that, in the present embodiment, the grasped member 6 and the holder 3 are attachably and detachably formed. However, for example, the grasped member 6 and the holder 3 may be integrally provided.
The grasping member 7 is not particularly limited as long as the grasping member 7 can rotatably grasp the brush-like grinding wheel 1. To suppress wear and heat generation of the grasping member 7, the grasping member 7 preferably includes a bearing. For example, a ball bearing, a roller bearing, a tapered roller bearing, a needle bearing, or the like can be used. From the viewpoint that rolling resistance is small, which is suitable for high-speed rotation, the ball bearing is favorable. Note that, in the present embodiment, the ball bearing is used as the grasping member 7. A plurality of bearings is preferably provided with respect to a shaft.
As described above, the brush-like grinding wheel 1 is rotatably grasped by the grasping member 7. Therefore, in the case of causing the brush-like grinding wheel 1 and the workpiece 20 in contact with each other while causing the brush-like grinding wheel 1 and the workpiece 20 to perform a relative motion, the brush-like grinding wheel 1 can be rotated using a force generated in a contact surface in the brush-like grinding wheel 1 with the workpiece 20 as a driving force. For example, in the case of bringing the brush-like grinding wheel 1 in contact with the workpiece 20 that performs a motion such as rotation, the brush-like grinding wheel 1 can be rotated using kinetic energy of the workpiece as the driving force. Therefore, in the case of using the polishing machine brush 12 of the present embodiment as a tool such as a lathe, the brush-like grinding wheel 1 comes in contact with the workpiece while being rotated by the kinetic energy of the workpiece. As a result, a contact point of the brush-like grinding wheel 1 with the workpiece is not fixed, and the deburring and polishing effects can be sufficiently obtained. Further, when the brush-like grinding wheel 1 comes in contact with the rotated workpiece, slippage occurs at the contact point, and in the case where the brush-like grinding wheel is rotated, a rotation ratio of the brush-like grinding wheel and the workpiece does not become 1:1. Therefore, an excellent brush effect can be obtained.
The grasping member 7 is provided with two screw holes in point symmetrical positions around the shaft insertion hole in the grasping member 7, and is connected with the axial position adjustment member 9 with screws. The axial position adjustment member 9 is connected with the fixed member 10, and can be rotated about a connection part as an axis. By moving the axial position adjustment member 9, a contact portion of the linear grinding materials 2 and the workpiece can be easily adjusted. An excellent polishing effect can be obtained by appropriately adjusting the contact portion of the linear grinding materials 2 and the workpiece according to types of the linear grinding materials and the workpiece, a purpose of working, and the like.
The fixed member 10 is fixed with a tool holding member 21 of the machine tool. In the present embodiment, the fixed member 10 is formed in an approximately rectangular parallelepiped shape. However, the shape of the fixed member 10 is not particularly limited as long as the fixed member 10 can be fixed with a tool holder of the machine tool.
A tool holder 11 according to an embodiment of the present invention is a part that constitutes the polishing machine brush 12 illustrated in
Note that, in the present embodiment, the tool holder 11 grasps the polishing machine brush. However, when performing cutting work, the tool holder 11 grasps a tool such as a bite in place of the polishing machine brush.
A first embodiment according to a working method of the present invention is a method of working a workpiece while causing the workpiece to perform a rotary motion, using a polishing machine brush 12 as a polishing tool in a machine tool such as a lathe not having power to rotate a tool. A brush-like grinding wheel 1 is brought in contact with an end surface of a workpiece 20 from a direction along an axis of rotation of the workpiece 20, whereby the brush-like grinding wheel 1 is rotated by a rotating force of the workpiece 20 and works the workpiece 20. Since the brush-like grinding wheel 1 comes in contact with the workpiece 20 while being rotated, a contact point in the brush-like grinding wheel 1 with the workpiece 20 is not fixed. Therefore, deburring and polishing effects can be sufficiently obtained, and extreme wear of only a part of the brush-like grinding wheel 1 can be prevented and the life of the brush-like grinding wheel 1 can be elongated.
Since the deburring and polishing effects are exhibited as the brush-like grinding wheel is rotated in reaction to rotation of the workpiece 20, it is desirable to adjust a cutting amount and a rotational speed of the workpiece so that the brush-like grinding wheel is rotated. The rotational speed of the workpiece 20 is not particularly limited. However, the rotational speed is preferably 50 rpm or more, and more preferably 1000 rpm or more.
In
For example, at the point P2, a resistance force Fr generated when the brush-like grinding wheel 1 runs over the workpiece 20 acts on the brush-like grinding wheel 1 in a direction opposite to the force Ft2. In the case where the force Ft2 in the tangential direction that the brush-like grinding wheel 1 receives from the workpiece 20 exceeds the resistance force Fr at point P2, that is, in the case of Ft2>Fr, when the brush-like grinding wheel 1 is brought in contact with the rotated workpiece 20, a force acts to rotate the brush-like grinding wheel 1 at the point P2. On the other hand, when the force Ft2 in the tangential direction that the brush-like grinding wheel 1 receives from the workpiece 20 falls below the resistance force Fr at the point P2, that is, in the case of Ft2<Fr, the force to rotate the brush-like grinding wheel 1 does not act at the point P2.
Here, the relationship between the force F that a brush-like grinding wheel 1 received from a workpiece 20 and the resistance force Fr generated when the brush-like grinding wheel 1 runs over the workpiece 20 at the point P2 has been described. However, the force F that a brush-like grinding wheel 1 received from a workpiece 20 and the resistance force Fr generated when the brush-like grinding wheel 1 runs over the workpiece 20 are generated on the entire contact surface of the workpiece 20 and the brush-like grinding wheel 1. Whether the brush-like grinding wheel 1 is rotated or not rotated is determined according to whether which of a total sum ΣFt of the forces Ft in the tangential direction that a brush-like grinding wheel 1 received from a workpiece 20 on the contact surface of the workpiece 20 and the brush-like grinding wheel 1, and a total sum ΣFr of the resistance forces Fr generated on the contact surface of the workpiece 20 and the brush-like grinding wheel 1 becomes larger. The brush-like grinding wheel 1 is rotated when the total sum ΣFt of the forces Ft in the tangential direction becomes larger than the total sum ΣFr of the resistance forces Fr, and the brush-like grinding wheel 1 is not rotated when the total sum ΣFt of the forces Ft in the tangential direction becomes smaller than the total sum ΣFr of the resistance forces Fr.
The resistance force Fr generated when the brush-like grinding wheel 1 runs over the workpiece 20 can be mainly adjusted according to the cutting amount of the brush-like grinding wheel 1 into the workpiece 20. The resistance force Fr increases as the cutting amount increases. In the present specification, a cutting amount refers to a moving amount of a tip end surface of the brush-like grinding wheel when the brush-like grinding wheel is further pressed against the workpiece from a state where the tip end surface of the brush-like grinding wheel is in contact with the workpiece without applying a stress to the brush.
In the present embodiment, in the case of deburring an edge portion of the workpiece 20, a portion where the deburring function occurs, and a portion to which the driving force is transmitted from the workpiece 20, in the brush-like grinding wheel 1, are different.
The curve 31 is the broken line drawn on a left side with respect to the circumference in the case where the force to rotate the brush-like grinding wheel 1 acts in an A direction, and is the broken line drawn on a right side with respect to the circumference in the case where the force to rotate the brush-like grinding wheel 1 acts in a B direction, at points on the circumference connecting the points P1 and P2 of the brush-like grinding wheel 1. Further, the curve 31 is drawn on a position more distant in a horizontal direction from the circumference of the brush-like grinding wheel 1 as the force to rotate the brush-like grinding wheel 1 in the A direction or the force to rotate the brush-like grinding wheel 1 in the B direction becomes larger.
In
In the case of bringing the brush-like grinding wheel 1 in contact with the workpiece 20 from the end surface 20a of the workpiece 20, the end surface 20a being orthogonal to the axis of rotation of the workpiece 20, whether the brush-like grinding wheel 1 is rotated in the same direction as the rotating direction of the workpiece 20 or is rotated in the opposite direction to the rotating direction of the workpiece 20 differs depending on a magnitude relationship between the diameter of the workpiece 20 and the diameter of the brush-like grinding wheel 1, the lap percentage, or the cutting amount. For example, in the case where the diameter of the workpiece 20 is the same as the diameter of the brush-like grinding wheel 1, the brush-like grinding wheel 1 tries to rotate in the opposite direction to the rotating direction of the workpiece 20 when the lap percentage is less than 100%, the brush-like grinding wheel 1 is not rotated when the lap percentage is 100%, and the brush-like grinding wheel 1 tries to rotate in the same direction as the rotating direction of the workpiece 20 when the lap percentage exceeds 100%.
In the first embodiment, the working method of bringing the brush-like grinding wheel 1 in contact with the end surface 20a of the workpiece 20 from the direction along the axis of rotation of the workpiece 20 has been described. However, in a second embodiment, a working method of bringing a brush-like grinding wheel 1 in contact with a side surface 20b of a workpiece will be described. In the working method according to the second embodiment, the brush-like grinding wheel 1 is brought in contact with the side surface 20b of the workpiece that performs a rotary motion, whereby the brush-like grinding wheel 1 is rotated and removes burr and unevenness existing on the side surface 20b of the workpiece.
On the other hand,
In the case where the workpiece 20 has a columnar shape, when the brush-like grinding wheel 1 is brought in contact with the side surface 20b of the workpiece such that the tip end surface of the brush-like grinding wheel 1 becomes parallel to the side surface 20b of the workpiece (that is, the tip end surface of the brush-like grinding wheel 1 becomes parallel to the tangential plane of the side surface 20b of the workpiece), the brush-like grinding wheel 1 is not rotated if the entire tip end surface of the brush-like grinding wheel 1 is in contact with the side surface 20b. To rotate the brush-like grinding wheel 1, the tip end surface of the brush-like grinding wheel 1 being in contact with the side surface 20b of the workpiece not to become parallel to each other, as illustrated in
In the first and second embodiments, the working method of the case where the workpiece 20 performs a rotary motion has been described. However, in a third embodiment, a working method of a case where a workpiece 20 is fixed and a brush-like grinding wheel 1 performs an orbital motion will be described.
The brush rotating mechanism 13 is not particularly limited as long as the brush rotating mechanism 13 can rotate the shaft 14. For example, a known motor such as a motor with brush, a brushless motor, a stepping motor, or the like can be used.
A fourth embodiment according to the present invention is a method of working a workpiece 22, using a polishing machine brush 12 as a polishing tool, while causing the workpiece 22 to perform a linear motion.
Although the contact method of the workpiece 22 and the brush-like grinding wheel 1 is not particularly limited, from the viewpoint to increase a rotating force of the brush-like grinding wheel and to improve the deburring effect, it is favorable that a contact region of the brush-like grinding wheel with the workpiece becomes asymmetrical in the case where a straight line passing through a rotation center in the tip end surface of the brush-like grinding wheel and parallel to a direction of a force received by the brush-like grinding wheel from the workpiece 22 is an axis of symmetry.
The brush-like grinding wheel 1 is grasped by a tool holder 11 including a grasping member 7 and a fixing jig 8. A method of fixing the tool holder 11 to a machine tool is not particularly limited, and an example includes fastening the tool holder 11 to the machine tool with a screw.
The brush-like grinding wheel 1 is brought in contact with the workpiece 22 that performs a linear motion, and the brush-like grinding wheel 1 is rotated by a force received from the workpiece 22 to work the workpiece 22. Since a contact point in the brush-like grinding wheel 1 with the workpiece 22 is not fixed, deburring and polishing effects can be sufficiently obtained, and extreme wear of only a part of the brush-like grinding wheel 1 can be prevented and the life of the brush-like grinding wheel 1 can be elongated.
Since the deburring and polishing effects are exhibited as the brush-like grinding wheel is rotated in reaction to the linear motion of the workpiece 22, it is desirable to adjust a cutting amount and a speed of the linear motion of the workpiece so that the brush-like grinding wheel is rotated. The speed of the linear motion in the workpiece 22 is not particularly limited. However, the speed is preferably 5 m/min or more, and more preferably 20 m/min or more.
The working method according to the fourth embodiment rotates, in a case of conveying the workpiece 22 or the like, the brush-like grinding wheel 1 using the linear motion in conveying the workpiece 22 to enable deburring. Further, in the case of causing the workpiece 22 to perform a reciprocating motion by a ball screw linear motion unit provided with a drive source such as a servomotor, the working method according to the fourth embodiment can rotate the brush-like grinding wheel 1 using the linear motion of the workpiece 22 to enable deburring.
In the fourth embodiment, the working method of the case where the workpiece 20 performs a linear motion has been described. However, in a fifth embodiment, a working method of a case where a workpiece 20 is fixed and a brush-like grinding wheel 1 performs a linear motion will be described.
A brush-like grinding wheel and an end surface of a workpiece were brought in contact with each other while changing the lap percentage in conditions of the cutting amount of 0.1 mm and the rotational speed of the workpiece of 2000 rpm, using the workpiece with the diameter of 100 mm and the brush-like grinding wheel with the diameter of 100 mm. The rotating direction of the brush-like grinding wheel at each lap percentage and the polishing effect on the workpiece were evaluated. Results are shown in Table 1. In Table 1, the W diameter represents the diameter of the workpiece, and the B diameter represents the diameter of the brush-like grinding wheel. Further, “o” indicates a case where the deburring/polishing effect to the end surface of the workpiece and its edge portion was exhibited, “NA” indicates that the brush-like grinding wheel did not act on the end surface of the workpiece and its edge portion and the deburring/polishing effect was not exhibited, and “x” indicates that the brush-like grinding wheel was not rotated.
The end surface of the workpiece and the brush-like grinding wheel were brought in contact with each other, similarly to Example 1, except that the diameter of the workpiece and the diameter of the brush-like grinding wheel were changed as shown in Table 1. The rotating direction of the brush-like grinding wheel at each lap percentage and evaluation of the deburring/polishing effect on the workpiece are shown in Table 1.
The end surface of the workpiece and the brush-like grinding wheel were brought in contact with each other, similarly to Example 1, except that the diameter of the workpiece and the diameter of the brush-like grinding wheel were changed as shown in Table 2. The rotating direction of the brush-like grinding wheel at each lap percentage and evaluation of the polishing effect on the workpiece are shown in Table 2. Note that the largest lap percentage in Example 4 is 120% and the largest lap percentage in Example 5 is 50%. Both of the examples are a case in which the entire brush-like grinding wheel is inside the workpiece in top view.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2016/051310 | 1/18/2016 | WO | 00 |
