This application is the U.S. National Phase of and claims priority to International Patent Application No. PCT/JP2018/010353, International Filing Date Mar. 15, 2018, entitled Stator And Uniaxial Eccentric Screw Pump; which claims benefit of Japanese Patent Application No. JP 2017-053825 filed Mar. 20, 2017; both of which are incorporated herein by reference in their entireties.
The present invention relates to a stator and a uniaxial eccentric screw pump.
Conventionally, a uniaxial eccentric screw pump is provided for transferring fluid substance. The uniaxial eccentric screw pump has a stator formed with an internally-threaded insertion hole, and an externally-threaded rotor which is inserted into the insertion hole of the stator and eccentrically rotates. Moreover, most of stators of the uniaxial eccentric screw pump have an outer cylinder made of a hard material such as metal, and a stator main body which is formed by molding elastomer, such as rubber or silicone and formed with the internally-threaded insertion hole. The outer cylinder and the stator main body are fixed to an inner circumferential surface of the outer cylinder by a method, such as adhesion with adhesives or pressure joining by heat.
The uniaxial eccentric screw pump provided with the stator described above is disclosed as the following Patent Document 1: JP2004-360469A which was filed by the present applicant. As illustrated in
The stator 520 disclosed in Patent Document 1 is elastically deformed so that the gasket parts 546 and 547 expand radially due to influences etc. of the pressing force received from the end stud 513 (nozzle) etc. when attached to the uniaxial eccentric screw pump. Thus, relative positions between the gasket parts 546 and 547 and outer cylinder ends 532 and 533 deviate, and there is a concern on which large stresses act near the ends of adhesion areas A.
Describing more concretely, as illustrated in
Thus, as the attachment and removal of the stator 520 to/from the uniaxial eccentric screw pump are repeated, the action (change) of the stress accompanying the elastic deformation of the gasket parts 546 and 547 is repeated in the adhesion areas A between the gasket parts 546 and 547 and the outer cylinder 530. Thus, loads of the adhesion areas A between the gasket parts 546 and 547 and the outer cylinder 530 are accumulated, and the adhesion areas A have a concern of being damaged soon or later by peel-off, crack, etc.
When parts of the adhesion areas A peel off as described above, there is a concern in which a gap is produced between the gasket parts 546 and 547 (stator main body 542) and the outer cylinder 530. If the transfer liquid infiltrates into such a gap, the damage by peel-off, crack, etc. in the adhesion areas A spreads, and the life of the stator 520 may be shortened.
Moreover, in these days, the demand of small-sized stators for carrying a small quantity of transfer liquid has been increased. In the case of such a small-sized stator, the gasket parts and the outer cylinder are naturally reduced in the size and, thus, the adhesion areas between the gasket parts and the outer cylinder inevitably decrease to weaken the adhesiveness. Thus, in the case of the small-sized stator, there is a concern that the possibility of occurrence of the peel-off, crack, etc. in the adhesion areas A as described above further increases.
Therefore, one purpose of the present invention is to provide a long-life stator and a uniaxial eccentric screw pump provided with the stator, which enable a comparatively extended period of use by preventing damage of the stator due to repeating of attachment and removal to/from the uniaxial eccentric screw pump.
In order to solve the problem described above, a stator according to the present invention is a stator of a uniaxial eccentric screw pump structured so that an externally threaded rotor is rotatably inserted into the stator formed with an internally-threaded insertion hole, and a transferring object is transferred by eccentrically rotating the rotor via a drive source. The stator includes a stator main body, molded with elastomer, and formed in an inner circumferential surface thereof with the internally-threaded insertion hole extending in axial directions of the stator, and an outer cylinder attached externally to the stator main body. The stator main body includes a flange-shaped gasket part in at least one end thereof. The stator includes a fixing area to which the gasket part and the outer cylinder are adhered. One or both of the outer cylinder and the gasket part has a derricking part protruding or being dented in the axial directions of the stator. The derricking part is made into such a shape that at least part of one of the outer cylinder and the gasket part is fitted into the other. The derricking part and the fixing area are provided to at least one of both ends of the stator, and prevent a deformation of at least part of the gasket part due to pressing of the stator in the axial directions.
The stator of the present invention is provided with the derricking part protruding or being dented in the axial direction. Thus, the stator of the present invention is structured such that, in the derricking part, the gasket part and the outer cylinder are fitted to each other in the axial direction. Therefore, in the stator of the present invention, the fitting structure thus formed in the derricking part effectively acts on restricting a radial elastic deformation of the gasket part which is expected to occur accompanying expansion and contraction of the stator main body, etc. In this manner, according to the present invention, a deviation of the relative positions between the gasket part and the outer cylinder is prevented. Further, the stator of the present invention thereby reduces damage of the area to which the gasket part and the outer cylinder are adhered (fixing area) accompanying the elastic deformation of the gasket part. As a result, the life of the stator is prevented from being shortened.
Moreover, according to the present invention, all or part of the derricking part can be the fixing area. Thus, compared to a case where the fixing area is a flat surface like the adhesion area A of the conventional stator, the stator of the present invention expands the fixing area by expanding the area of the part where the gasket part and the outer cylinder are adjacent (contact) to each other.
The stator of the present invention is desirable to include a wall surface that forms a side surface of the derricking part provided to the end of the outer cylinder, and the wall surface is desirable to restrict the deformation in a direction intersecting with the axial directions of the stator in at least part of the gasket part.
The stator of the present invention includes the wall surface that forms the side surface of the derricking part provided to the end of the outer cylinder. Also, in the stator of the present invention, the wall surface can effectively function so as to restrict that at least the part of the gasket part deforms in the direction intersecting with the axial directions of the stator (e.g., the radial direction when the stator has a cylindrical shape. Hereinafter, “direction intersecting with the axial directions of the stator” may be referred to as “radial direction” unless otherwise specified). Therefore, the stator of the present invention reduces damage, etc. of the area to which the gasket part and the outer cylinder are adhered (fixing area) accompanying the elastic deformation of the gasket part.
The stator of the present invention is desirable to include a wall surface that forms a side surface of the derricking part provided to the end of the outer cylinder, and all or part of the wall surface is desirable to be formed so as to conform to all or part of the contour of the circumferential surface of the gasket part.
The stator of the present invention includes the wall surface that forms the side surface of the derricking part provided to the end of the outer cylinder. Also, in the stator of the present invention, all or part of the wall surface is formed so as to conform to all or part of the contour of the gasket part and, thus, the elastic deformation of the gasket part in the direction intersecting with the axial directions of the stator is restricted. Therefore, according to the present invention, the damage, etc. of the area to which the gasket part and the outer cylinder are adhered (fixing area) accompanying the elastic deformation of the gasket part is reduced.
The stator of the present invention is desirable to include a wall surface that forms a side surface of the derricking part provided to the end of the outer cylinder, and all or part of the wall surface is desirable to be arranged so as to oppose to at least part of the circumferential surface of the gasket part.
According to the structure, the wall surface is arranged to oppose to the outer side (i.e., circumferential surface) of the gasket part. Thus, the stator of the present invention efficiently restricts the radially-outward elastic deformation of the gasket part. In detail, when the gasket part is pressed in the axial directions, the radially-outside area thereof deforms greatly and large stress acts thereon. By the above structure, the stator of the present invention restricts the radially-outward elastic deformation of the gasket part in the part adjacent to the circumferential surface of the gasket part where the large stress is expected to occur.
Here, the conventional stator is structured such that the area where the gasket part formed in a substantially flat shape is joined to a substantially flat end face provided to the end of the outer cylinder (joining area) is provided (see
In view of the above described problems, the stator of the present invention is desirable to include a wall surface that forms a side surface of the derricking part provided to the end of the outer cylinder, and all or part of the wall surface is desirable to be arranged so as to surround the circumferential surface of the gasket part.
According to the structure, in the part where the wall surface is arranged to surround the gasket part, it is prevented that nails, thin instruments, etc. enter between the gasket part and the outer cylinder. Thus, the possibility of occurrence of an unexpected defect, such as the peel-off, crack, etc. in the joining part of the gasket part and the outer cylinder, is reduced.
Further, when structured as above, the radial elastic deformation of the gasket part in the part where the wall surface is arranged to surround the gasket part is restricted. Moreover, when being structured as above, it becomes possible to adhere the circumference of the gasket part and the wall surface, and the area to which the gasket part and the outer cylinder are adhered (fixing area) is further increased in size. Thus, the gasket part and the outer cylinder are adhered more firmly.
Additionally, structuring the stator of the present invention as above is preferable in a case of molding the stator main body using a die. In detail, when molding the stator main body using the die, a process of removing the die is performed. At the time, if removing the die while the gasket part is adhering to the die, the gasket part is pulled by the die and it may become a cause of occurrence of peel-off, etc. in the fixing area. However, the stator of the present invention is structured with the part where the wall surface is arranged to surround the gasket part as described above. Thus, according to the structure, the contact area between the part forming the gasket and the die becomes smaller by the area of the part provided with the wall surface around in the circumferential surface of the gasket part. Therefore, according to the present invention, even in a case where the stator main body is molded with the die, the stator which can be manufactured without occurrence of peel-off, etc. in the fixing area, is provided.
The stator of the present invention is desirably structured to include a wall surface that forms a side surface of the derricking part provided to the end of the outer cylinder, and an accommodation area structured inside the wall surface. All or part of the wall surface is desirable to be arranged so as to surround the circumferential surface of the gasket part, and the gasket part is desirable to have a part accommodated in the accommodation area, and a part protruded in the axial direction of the stator from the accommodation area.
According to the structure, by interposing the part of the gasket part protruded in the axial direction of the stator from the accommodation area (hereinafter, may also be referred to as the “protruding part”) between another member which is the object to be joined, sufficient sealing performance with respect to the object to be joined is secured. In detail, when attaching the stator of the present invention to a uniaxial eccentric screw pump, by interposing the protruding part of the gasket part between the other member which is the object to be joined (e.g., a member referred to as the end stud, etc.), it can effectively act in securing the sealing performance.
Similar to the above described structure, with the stator of the present invention, the part where the wall surface is arranged to surround the gasket part exists. Thus, it is prevented that nails, thin instruments, etc. enter between the gasket part and the outer cylinder, and the occurrence of an unexpected defect accompanying the peel-off, etc. in the joining part of the gasket part and the outer cylinder, is reduced.
Further, by providing the wall surface descried above, the radial elastic deformation of the gasket part in the part where the wall surface is arranged is restricted. Moreover, by the wall surface adhering between the gasket part and the outer cylinder, the wall surface can be utilized to expand the fixing area of the gasket part and the outer cylinder. Therefore, according to the present invention, the gasket part and the outer cylinder are adhered more firmly.
Additionally, the present invention is effective when manufacturing a high quality stator in a case where the stator main body is molded with the die. In detail, in the stator of the present invention, the part where the wall surface is arranged to surround the gasket part exists, and the contact area between the part forming the gasket and the die becomes smaller by the amount. Therefore, according to the present invention, even in a case where the stator main body is molded with the die, the high quality stator can be provided without the peel-off, etc. in the fixing area.
As for the stator of the present invention, the derricking part provided to the end of the outer cylinder may be the outer cylinder end having a step in the axial direction of the stator.
According to the structure, the radial elastic deformation of the gasket part is restricted.
As for the stator of the present invention, the derricking part provided to the end of the outer cylinder may be provided with one or both of a concave part formed in a concave in the axial direction of the stator and a convex part formed in a convex.
According to the structure, by the convex part and the concave part forming the derricking part, the fitting structure is provided to the gasket part and the outer cylinder end part.
As for the stator of the present invention, the gasket part and the outer cylinder are desirable to be fixed by adhesion with adhesives or pressure joining by heat.
In the stator of the present invention, by having the above described structure in which the gasket part and the outer cylinder are fitted to each other in the axial direction in the derricking part, the radial elastic deformation of the gasket part is restricted. Thus, the stator of the present invention can be used stably without excess force acting on the adhering part or pressure joining part between the gasket part and the outer cylinder even in a situation where the radial elastic deformation of the gasket part, etc. may occur.
A uniaxial eccentric screw pump of the present invention includes the stator of the present invention described above.
According to the present invention, the uniaxial eccentric screw pump provided with the long-life stator can be provided.
According to the present invention, the long-life stator and the uniaxial eccentric screw pump provided with this stator, which enable the comparatively extended period of use, can be provided by preventing the damage of the stator due to the repeating of attachment and removal to/from the uniaxial eccentric screw pump.
Hereinafter, a uniaxial eccentric screw pump 10 and a stator 20 according to one embodiment of the present invention will be described in detail with reference to the drawings. Note that, although the uniaxial eccentric screw pump 10 has a feature in the stator 20, the entire structure is described in the following, prior to description of the stator 20.
«Entire Structure of Uniaxial Eccentric Screw Pump 10»
The uniaxial eccentric screw pump 10 is a so-called rotary displacement pump. As illustrated in
The pump casing 16 is a cylindrical member made of metal, and is provided at one end side in the longitudinal directions with a stator attaching part 16a. Moreover, the stator casing 18 is provided at an end stud 13 attached to one end side in the longitudinal directions with a first opening part 14a. Moreover, a second opening part 14b is provided to the outer circumferential part of the pump casing 16. The second opening part 14b communicates with an interior space of the pump casing 16 in an intermediate part in the longitudinal directions of the pump casing 16.
The first opening part 14a and the second opening part 14b are parts which function as a discharge port and a suction port of the uniaxial eccentric screw pump 10, respectively. The uniaxial eccentric screw pump 10 makes the first opening part 14a function as the discharge port and the second opening part 14b as the suction port by rotating the rotor 50 in the positive direction. Alternatively, it makes the first opening part 14a function as the suction port and the second opening part 14b as the discharge port by rotating the rotor 50 in the opposite direction for maintenance etc. to clean up the interior space etc. of the pump casing 16.
The stator 20 is accommodated in the stator casing 18 in a state where one end thereof is adjacent to the end stud 13 and the other end is fitted into the stator attaching part 16a of the pump casing 16.
The stator 20 is a member having the appeared shape of a substantially cylindrical shape. The stator 20 has a cylindrical outer cylinder 30 made of metal, and a stator main body 42 made of elastic material such as rubber, or elastomer such as resin. The stator 20 is structured so that the stator main body 42 is formed inside the outer cylinder 30.
The stator main body 42 accommodates a cylindrical part 44 (described below) in the outer cylinder 30. The outer diameter of the stator main body 42 is substantially the same as the inner diameter of the outer cylinder 30. Thus, the stator main body 42 is attached in a state where the outer circumferential surface thereof substantially closely contacts an inner circumferential surface 30a of the outer cylinder 30, and is formed integrally by a fixing means, such as adhesives. As illustrated in
The rotor 50 is a shaft body made of metal, and is made into an external-thread shape with n−1 grooves and single twist or multiple twists. In this embodiment, the rotor 50 is made into an eccentric external-thread shape with one groove. The rotor 50 has a substantially perfect circular cross-sectional shape at any position in the longitudinal directions. The rotor 50 is inserted into the insertion hole 48 formed in the stator main body 42 described above, and is eccentrically rotatable inside the insertion hole 48.
When the rotor 50 is inserted into the stator 20, an outer circumferential wall 50a of the rotor 50 and the inner circumferential surface 42a of the stator main body 42 become in a state where they closely contact at their tangent lines, and a fluid conveying path 52 (cavity) is formed between the inner circumferential surface 42a of the stator main body 42 and the outer circumferential wall 50a of the rotor 50. The fluid conveying path 52 spirally extends in the longitudinal directions of the stator 20 and the rotor 50.
When rotating the rotor 50 inside the insertion hole 48 of the stator main body 42, the fluid conveying path 52 advances in the longitudinal direction of the stator 20 while rotating inside the stator main body 42. Thus, when the rotor 50 is rotated, fluid is sucked into the fluid conveying path 52 from one end side of the stator 20, is carried toward the other end side of the stator 20 in a state where the fluid is trapped inside the fluid conveying path 52, and is discharged at the other end side of the stator 20.
The power transmission mechanism 60 is to transmit a motive force from a drive source 58 to the rotor 50 described above. The power transmission mechanism 60 has a power transmitting part 64 and an eccentrically rotating part 62. The power transmitting part 64 is provided at one end side in the longitudinal directions of the pump casing 16. Moreover, the eccentrically rotating part 62 is provided to an intermediate part 54. The eccentrically rotating part 62 is a part which connects the power transmitting part 64 with the rotor 50 so as to be power-transmittable. The eccentrically rotating part 62 is provided with a coupling shaft 63 comprised of a conventionally-known coupling rod, a screw rod, etc. Thus, the eccentrically rotating part 62 is capable of transmitting to the rotor 50 the rotational driving force generated by actuating the drive source 58 to eccentrically rotate the rotor 50.
«Structure of Stator 20»
Below, the stator 20 of the present invention is described in detail. As illustrated in
Note that, in the following description, the axial directions of the stator 20 (longitudinal directions) is described referring to as “axial directions X.” Moreover, a state where the stator 20 is viewed in the axial direction X from the end stud 13 side is described referring to as “the front view.”
The stator 20 is structured such that the outer cylinder 30 is attached externally to the stator main body 42. The stator 20 is formed by integrating the outer cylinder 30 and the stator main body 42, for example, with a technique, such as pouring molding material of the stator main body 42 into the outer cylinder 30 to which adhesives are adhered. Note that the molding of the stator main body 42 will be described later.
As illustrated in
Moreover, the stator 20 has derricking parts 26 and 27. The derricking parts 26 and 27 are concave parts formed at both ends of the outer cylinder ends 32 and 33, respectively. The stator 20 is structured such that the gasket parts 46 and 47 are inserted (or penetrated) into the outer cylinder ends 32 and 33 in the axial directions X to the outer cylinder ends 32 and 33, respectively. In the stator 20 of this embodiment, the derricking part 26 and the fixing area 24 are provided to the stator end 22. Moreover, in the stator 20, the derricking part 27 and the fixing area 25 are provided to the stator end 23.
As illustrated in
The outer cylinder 30 of this embodiment is a cylindrical body having a substantially circular cross-section. As illustrated in
Note that, although the outer cylinder 30 has the substantially cylindrical appearance, it may be any kind of shapes, as long as it conforms to the shape of the stator main body 42. For example, the outer cylinder 30 may have a substantially oval cross-sectional shape (see
As illustrated in
As illustrated in
As illustrated in
As illustrated in
As illustrated in
The cylindrical part 44 has tapered parts where the diameter increases gradually near both ends. The gasket parts 46 and 47 are formed on both sides of the cylindrical part 44, and are made into the flange shape. Moreover, as illustrated in
Note that the gasket part 46 and the gasket part 47 have a similar structure. Thus, in the following description, the gasket part 46 is described in detail, and description of the gasket part 47 is omitted.
As illustrated in
As illustrated in
Next, an outline of a procedure to form the stator main body 42 in the outer cylinder 30 of this embodiment, and a damage control of the gasket parts 46 and 47 when molding the stator main body 42, are described.
When molding the stator main body 42 onto the outer cylinder 30, adhesives are first adhered to the inner circumferential surface 30a and the outer cylinder ends 32 and 33 of the outer cylinder 30. Next, the outer cylinder 30 is inserted into a given die M, and an internally-threaded core (not illustrated) is placed inside the outer cylinder 30. Next, elastomer used as the forming material of the stator main body 42 is poured therein. Thus, the stator main body 42 having the internally-threaded insertion hole 48 and the gasket parts 46 and 47 is molded in a state where it is adhered to the outer cylinder 30.
As illustrated in
Here, the stator 20 of this embodiment is molded so as to be in a state where part of the gasket part 46 is fitted into the derricking part 26 of the outer cylinder 30. More specifically, the gasket part 46 becomes in a state where part of the circumferential surface 46c in the axial directions X is fitted into the accommodation area 36. Moreover, parts other than the part accommodated in the accommodation area 36 of the gasket part 46 are formed in a state where they protrude outwardly in the axial direction X from the accommodation area 36. In other words, in the molding process of the stator main body 42, the part of the circumferential surface 46c of the gasket part 46 is adjacently located so as to oppose to the wall surface 34a, and other parts become parts which contact the die M.
Further describing, as illustrated in
Note that, although in the stator 20 of this embodiment, the stator main body 42 is formed by pouring the molding material of the stator main body 42 into the die M which accommodates the outer cylinder 30, but the stator of the present invention is not limited to this fabrication.
For example, the stator of the present invention may fix the stator main body 42 to the outer cylinder 30 by utilizing adhesiveness to the outer cylinder 30 which the molding material, such as elastomer, itself has, without using the intermediate material, such as adhesives. Moreover, the stator of the present invention may constitute the outer cylinder 30 by hard material made of resin, and may fix the outer cylinder 30 and the stator main body 42 by pressure with the effect of heat etc. Alternatively, the stator of the present invention may be fabricated by preparing the stator main body 42 and the outer cylinder 30 which are molded beforehand, fixing the molded stator main body 42 to the outer cylinder 30 integrally by adhesion with adhesives or pressure joining by heating. Thus, the stator of the present invention is suitably selectable of the fixing means of the outer cylinder 30 and the stator main body 42.
Next, a deformation control of the gasket parts 46 and 47 in the attachment and removal work of the stator 20 to the uniaxial eccentric screw pump 10 is described.
As illustrated in
Here, the gasket part 46 of this embodiment is molded in a state where the part of the circumferential surface 46c in the axial directions X is surrounded by the wall surface 34a. That is, the circumferential surface 46c of the gasket part 46 becomes in a state where it is surrounded by the wall surface 34a. As illustrated in
Thus, as for the stator 20, upon the attachment to the uniaxial eccentric screw pump 10, even if the pinching forces act on the gasket parts 46 and 47 from both sides in the axial directions X, at least the parts of the gasket parts 46 and 47 accommodated in the accommodation areas 36 and 37 are controlled in the radial elastic deformation. Thus, shear forces in the radial directions of the stator 20 acting on the fixing areas 24 and 25 can be inhibited. Moreover, since the gasket parts 46 and 47 are attached in a state where their radial elastic deformations are controlled, elastic deformations to contract the gasket parts 46 and 47 in the radial direction hardly take place when removing the stator 20 from the uniaxial eccentric screw pump 10. Thus, as for the stator 20, even if the pinching force acting on the gasket parts 46 and 47 upon the attachment and removal to/from the uniaxial eccentric screw pump 10 varies, the radial deformation of the gasket parts 46 and 47 hardly takes place. Therefore, as for the stator 20, a defect, such as the gasket parts 46 and 47 being peeled off from the outer cylinder ends 32 and 33, does not easily occur.
Next, a function of the gasket parts 46 and 47 as seal members, in the stator 20 of this embodiment, is described.
As illustrated in
As illustrated in
Then, a stator 120 according to a second embodiment of the present invention is described. Note that, in the following description of the stator 120, similar structures to the stator 20 will be described using the same characters as those assigned in the description of the stator 20 to omit detailed description thereof.
As illustrated in
As illustrated in
Moreover, the stator 120 has derricking parts 126 and 127. The derricking parts 126 and 127 are convex parts formed in the outer cylinder ends 132 and 133, respectively. The stator 120 is structured so that the derricking parts 126 and 127 provided in the outer cylinder ends 132 and 133 are fitted into the concave parts formed in the gasket parts 146 and 147 (or protruded) in the axial directions X.
As illustrated in
As described above, the outer cylinder 130 has the derricking part (convex part) 126. The derricking part 126 of this embodiment is a convex part formed in the outer cylinder end 132. Moreover, the derricking part 126 forms in the outer cylinder end 132 a step which protrudes in the axial direction X toward the end stud 13.
As illustrated in
As illustrated in
As illustrated in
Next, a deformation control of the gasket parts 146 and 147 of the stator 120 is described. Note that, since the gasket parts 146 and 147 have similar structures, the gasket part 146 is described in the following description of this embodiment, and description of the gasket part 147 is omitted.
Similar to the stator 20 of the first embodiment, when the stator 120 is attached to the uniaxial eccentric screw pump 10, the gasket part 146 is pinched between the outer cylinder end 132 and the end stud 13, and becomes in a state where it is pressed from both sides in the axial directions X. The gasket part 146 tends to be elastically deformed radially outward of the stator 120 by receiving the pressing force from both sides in the axial directions X.
Here, the derricking part 126 of this embodiment demonstrates a function like an anchor at a radially intermediate location of the gasket part 146. Specifically, the derricking part 126 restricts a diameter increase of the gasket part 146 disposed inward of the inner wall surface 134a. Thus, the stator 120 can control that the adhesion of the fixing area 124 comes off by reducing the stress acting on the fixing area 124 where the gasket part 146 and the outer cylinder end 132 are adhered. Moreover, the stator 120 restricts the elastic deformation radially inward of the gasket part 146 by the outer wall surface 134b when removed from the uniaxial eccentric screw pump 10.
Thus, the stator 120 restricts the elastic deformation of the gasket part 146 which is expected when attaching and removing to/from the uniaxial eccentric screw pump 10. Moreover, the stator 120 restricts the elastic deformation of the gasket part 146 to reduce the stress of the fixing area 124 and prevent the peel-off of the outer cylinder 130 and the stator main body 142. As a result, damage of the stator 120 can be controlled.
Moreover, the stator 120 can make all or some area of the inner wall surface 134a and the outer wall surface 134b as the fixing area 124, in addition to the end face 132a and the tip-end face 134c. That is, the stator 120 can expand the adhesion area of the stator main body 142 and the outer cylinder end 132 by the area of the inner wall surface 134a and the outer wall surface 134b which constitute the circumferential surfaces (side surfaces) of the derricking part 126. Thus, as compared with the conventional stator 520, the adhesiveness of the gasket part 146 and the outer cylinder end 132 is improved, and the gasket part 146 peeling off from the outer cylinder end 132 can be prevented.
Next, a stator 220 according to a third embodiment of the present invention is described. Note that, in the following description, similar structures to the stator 20 are described using the same characters to omit detailed description thereof.
As illustrated in
The stator 220 has stator ends 222 and 223 at both ends in the axial directions X. Fixing areas 224 and 225 are provided to the stator ends 222 and 223, respectively. Moreover, the outer cylinder 230 has outer cylinder ends 232 and 233 (ends) at both ends in the axial directions X. The stator 220 has the fixing areas 224 and 225 in contact parts of the outer cylinder ends 232 and 233 and the gasket parts 246 and 247, respectively. The stator 220 is formed by fixing the outer cylinder ends 232 and 233 and the gasket parts 246 and 247 by adhesives etc. in the fixing areas 224 and 225, respectively.
The stator 220 has derricking parts 226 and 227 at both ends in the axial directions X. The stator 220 has the derricking part 226 and the fixing area 224 at the stator end 222, and has the derricking part 227 and the fixing area 225 at the stator end 223. Note that, in the description of this embodiment, description of the derricking part 227, the outer cylinder end 233, the gasket part 247, and the fixing area 225 is omitted.
As illustrated in
In the stator 220, the gasket part 246 is made into a derricking shape (concavo-convex shape) corresponding to the shapes of the concave part 235 and the convex part 238. Specifically, the gasket part 246 is made into a convex shape which protrudes in the axial direction X toward the outer cylinder end 232 at a position corresponding to the concave part 235. Moreover, the gasket part 246 is made into a concave shape which is dented in the axial direction X at a position corresponding to the convex part 238. Thus, the stator 220 is made into such a shape that the concavo-convex parts (derricking part) of the outer cylinder end 232 and the gasket part 246 are mutually fitted in the axial directions X in the part where the derricking part 226 is provided.
Further describing the derricking part 226 in detail, as illustrated in
Moreover, the derricking part 226 has a first bottom surface 234d, a top surface 234e, and a second bottom surface 234f, as surfaces substantially parallel to the end face 232a. The first bottom surface 234d is formed between the first wall surface 234a and the second wall surface 234b. The top surface 234e is formed between the second wall surface 234b and the third wall surface 234c. The second bottom surface 234f is formed inside the third wall surface 234c. The derricking part 226 forms steps between the end face 232a, and the first bottom surface 234d and the second bottom surface 234f.
As illustrated in
When the stator 220 is attached to the uniaxial eccentric screw pump 10, the gasket part 246 is pinched between the outer cylinder end 232 and the end stud 13, and becomes in a state where it is pressed from both sides in the axial directions X. The gasket part 246 tends to be elastically deformed radially outward of the stator 220 by receiving the pressing force from both sides in the axial directions X. The stator 220 restricts the radial elastic deformation of the gasket part 246 by the first wall surface 234a contacting the circumferential surface 246c of the gasket part 246 from radially outward. Moreover, the convex part 238 demonstrates a function like an anchor at a radially intermediate location to the gasket part 246 accommodated in the accommodation area 240. Thus, the stator 220 restricts the radially-outward and radially-inward elastic deformations of the gasket part 246 at an intermediate location of the gasket part 246, while restricting the radially-outward elastic deformation of the gasket part 246. That is, the stator 220 performs the dual-restriction of the elastic deformation of the gasket part 246. Thus, the stator 220 can prevent that the gasket part 246 peels off from the outer cylinder end 232 due to the elastic deformation of the gasket part 246.
Moreover, in the process of forming the stator main body 242 to the outer cylinder 230, the stator 220 is capable of using the first wall surface 234a, the second wall surface 234b, and the third wall surface 234c as the fixing area 224, in addition to the first bottom surface 234d, the top surface 234e, and the second bottom surface 234f. That is, the stator 220 is capable of expanding the adhesion area of the gasket part 246 and the outer cylinder end 232 by the area of the first wall surface 234a, the second wall surface 234b, and the third wall surface 234c which constitute the circumferential surface (side surface) of the derricking part 226. Thus, the stator 220 is capable of improving the adhesiveness of the gasket part 246 and the outer cylinder end 232 to prevent that the gasket part 246 peels off from the outer cylinder end 232.
As described above, although the first embodiment, the second embodiment, and the third embodiment of the present invention are described and the derricking parts of the stators 20, 120, and 220 are described in detail, the stator of the present invention is not limited to these structures.
Although the wall surface 34a having the shape which curves in the axial directions X is described in the description of the first embodiment and the inner wall surface 134a and the outer wall surface 134b which are formed along the axial directions X are described in the second embodiment, the shapes of the wall surfaces which the derricking part of the present invention has is not limited to these structures.
For example, as illustrated in
Further, the wall surface which the stator of the present invention has may be structured to be a wall surface substantially perpendicular to the bottom surface similar to the wall surface 301 illustrated in
Further, in the first embodiment, although the stator 20 having the derricking part 26 having the concave shape (concave part) made into the circular depression shape is described, the stator of the present invention is not limited to this structure. For example, the stator of the present invention may be a derricking part 312 made into an annular groove as illustrated
Moreover, as illustrated in
Further, in the description of each embodiment for the stator of the present invention described above, although the derricking part having one concave part or one convex part, or both the concave part and the convex part are described, the stator of the present invention is not limited to this structure.
For example, the stator of the present invention may have a derricking part provided with two convex parts, like a stator 330 illustrated in
In any case, the derricking part of the stator of the present invention may be any shape, as long as it is such a shape that at least one of the outer cylinder and the stator main body is fitted into the other.
Further, although in each embodiment of the stator of the present invention described above the outer cylinders 30, 130, and 230 having the circular cross-sectional shape, and the stators 20, 120, and 220 having the derricking parts 26, 134, and 234 having the circular or annular concave part or convex part are described, respectively, the outer cylinder and the derricking part which the stator of the present invention has are not limited to these structures.
For example, as illustrated in
Moreover, the stator of the present invention may be provided with the derricking part in one of the both ends in the axial directions X. Further, the stator of the present invention may be provided with derricking parts having different shapes in the both ends in the axial directions X. For example, in the stator of the present invention, the derricking part in one of the both ends may be the concave part, and the derricking part in the other end may be the convex part.
Moreover, as for the stator of the present invention, the materials of the outer cylinder and the stator main body may be suitably selectable in accordance with the type, property, etc. of the transferring object which is the object to be conveyed by using the uniaxial eccentric screw pump 10.
The stator of the present invention can be suitably used for the uniaxial eccentric screw pump or an application device which uses the uniaxial eccentric screw pump.
Number | Date | Country | Kind |
---|---|---|---|
JP2017-053825 | Mar 2017 | JP | national |
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/JP2018/010353 | 3/15/2018 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2018/173937 | 9/27/2018 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
3499389 | Seeberger | Mar 1970 | A |
3612734 | Dawson | Oct 1971 | A |
3838949 | Makino | Oct 1974 | A |
6460734 | Schroeder | Oct 2002 | B1 |
Number | Date | Country |
---|---|---|
1978-148303 | Nov 1978 | JP |
1991-32184 | Mar 1991 | JP |
H03-032184 | Jul 1991 | JP |
2004-360469 | Dec 2004 | JP |
2008-509313 | Mar 2008 | JP |
Entry |
---|
ISA/JP, International Search Report dated Jun. 19, 2018 in International Application No. PCT/JP2018/010353, total 4 pages with English translation. |
Intellectual Property India, Indian Office Action (with English translation) dated Aug. 13, 2021 in Indian Application No. 201937038672, 5 pages. |
Number | Date | Country | |
---|---|---|---|
20200080554 A1 | Mar 2020 | US |