JP2019130580A - Manufacturing method of piston of vehicle disc brake, spinning processor of piston of vehicle disc brake and piston of vehicle disc brake - Google Patents

Abstract

An object of the present invention is to form a corner portion between an outer peripheral end portion on an opening end side and an opening end portion into a desired R shape by spinning with a predetermined pressing roller without preforming a straight-shaped base material. To provide a method of manufacturing a piston for a vehicle disk brake. An annular groove is formed by rotating a bottomed cylindrical base material and pressing a groove forming roller provided with a convex groove forming portion from an outer peripheral surface of the base material. Then, an outer end forming section 42 in contact with the opening end side outer end 20 of the base material 15, an opening end forming section 41 in contact with the opening end 19 of the base 15, and an opening end side outer end 20 By pressing the corner forming roller 4 having the R-shaped corner forming portion 47 for forming the corner 21 between the opening end 19 and the opening end 19 from the opening end 19 and the outer peripheral surface 18, the opening end is formed. The outer peripheral end 20, the open end 19, and the corner 21 are formed. [Selection diagram] Fig. 1

Description

  The present invention relates to a method for manufacturing a piston of a vehicle disc brake, a spinning device for a piston of a vehicle disc brake, and a piston of a vehicle disc brake.

  A piston of a vehicle disc brake (hereinafter simply referred to as a piston) has a bottomed cylindrical shape, and has an outer peripheral surface that is slidable with respect to an inner peripheral wall of the cylinder body, and an open end that contacts the friction pad. . In the piston, an annular groove for mounting a rubber boot for waterproof and dustproofing is formed on the outer peripheral end of the outer peripheral surface on the opening end side.

  2. Description of the Related Art Conventionally, as a spinning device for a piston, a spinning device that rotates a base material (material) forged from iron, aluminum or the like around a rotation axis and performs plastic processing by a plurality of pressing rollers is known (Patent Document 1). : JP 2014-61534 A).

JP 2014-61534 A

  The piston spinning device described in Patent Document 1 includes a collet chuck that rotates a base material, a first roller that forms an annular groove in the base material, a second roller that forms an open end, A core pushing rod that presses and supports the bottom of the substrate from the opening side. In Patent Document 1, a straight-shaped base material is preformed to have a shape in which the opening is squeezed, and then, the base material having a shape in which the opening is squeezed by the first roller and the second roller is spun. I was processing. The conventional second roller has a simple straight cylindrical shape, and the shape of the corner portion of the forged substrate is left as it is. However, when the corner portion is a pin angle, stress is concentrated on the pin angle and durability is impaired. Therefore, it is necessary to shape the corners in advance so as not to become pin angles, and the number of machining steps increases due to the preliminary molding, resulting in a problem that the machining cost increases.

  Patent Document 1 does not assume that the corner portion between the opening end portion outer peripheral end portion and the opening end portion of the piston is formed by spinning. Further, the second roller is not structured to receive a load in a direction perpendicular to the rotation axis when the first roller forms an annular groove in the base material, and the bottom portion of the base material is opened from the opening side. A core pushing rod that supports the pressing is necessary to suppress the load on the collet chuck. However, if the core push rod and the peripheral mechanism are provided, the equipment cost becomes high, and if the core push rod is inserted and removed, there is a problem that the cycle time becomes long.

  The present invention has been made in view of the above circumstances, and by performing a spinning process with a predetermined pressing roller without preforming a straight base material, the angle between the opening end side outer peripheral end and the opening end is determined. Manufacturing method of a vehicular disc brake piston that forms a desired R-shaped portion, and a corner between the opening end side outer peripheral end and the open end can be molded into a desired R-shaped The present invention provides a spinning device for a piston of a vehicle disc brake, and a piston of a vehicle disc brake in which a corner between the outer peripheral end of the opening end and the opening end has a desired R shape. Objective.

  As an embodiment, the above-described problem is solved by a solution as disclosed below.

  The present invention relates to a method of manufacturing a piston of a vehicle disc brake by spinning processing, in which a bottomed cylindrical base material is rotated, and a groove forming roller provided with a convex groove forming portion is provided on the outer periphery of the base material. By pressing from the surface, an annular groove is formed on the outer peripheral surface, and an outer peripheral end forming portion that is in contact with the outer peripheral end portion on the opening end side of the base material, and an open end portion forming that is in contact with the open end portion of the base material A corner portion forming roller including a corner portion and an R-shaped corner portion molding portion that shapes a corner portion between the opening end portion outer peripheral end portion and the opening end portion, the opening end portion and the outer peripheral surface. The opening end portion side outer peripheral end portion, the opening end portion and the corner portion are formed by pressing from the side.

  According to the present invention, the shape of the concave R-shaped corner forming portion formed on the corner forming roller is transferred to the corner between the outer peripheral end on the opening end side and the opening end so as to be desired. Therefore, it is not necessary to pre-form into a shape with a narrowed opening as in the prior art, and the processing steps can be reduced, so that the processing cost can be suppressed. Further, even in a straight base material, the corner portion can be formed into a desired convex R shape by the corner portion forming roller.

  In the present invention, after the corner forming roller abuts on the base material, and the corner forming roller forms the opening end side outer peripheral end, the opening end, and the corner, the groove forming roller It is preferable that the groove forming roller forms the annular groove without coming into contact with the outer peripheral end on the opening end side. The opening end side outer peripheral end is not formed by the groove forming roller after being formed by the corner forming roller, so that the dimensional accuracy of the opening end side outer peripheral end, the opening end and the corner is good. To be kept.

  In the present invention, it is preferable that the bottom portion of the base material is supported from the outer peripheral surface side without being supported from the opening side, and the base material is molded by the groove forming roller and the corner portion forming roller. By pressing the corner forming roller from the opening end and the outer peripheral surface, the action of supporting the base material from the opening side works, so it is not necessary to support the bottom of the base material from the opening side, By eliminating the core pushing rod as in the prior art, the cycle time can be shortened.

  The present invention provides a spinning device for a piston of a vehicular disc brake, wherein the base of a bottomed cylindrical base material is supported from the outer peripheral surface without being supported from the opening side, and the first rotation shaft is used as an axis. A rotating part for rotating the material, a cylindrical groove forming roller provided with a convex groove forming part for rotating around the second rotation axis and forming an annular groove on the outer peripheral surface of the substrate; Rotating around the third rotation axis as an axis, forming an outer peripheral end portion for forming the outer peripheral end portion on the opening end side of the base material, and forming an open end portion for forming the open end portion of the base material And a cylindrical corner forming roller provided with an R-shaped corner forming portion for forming a corner between the opening end side outer peripheral end and the opening end, The second rotation axis is parallel to the first rotation axis, and the third rotation axis is orthogonal to the first rotation axis. In addition, the groove forming roller moves the groove forming portion closer to the first rotation shaft to bring the groove forming portion into contact with the outer peripheral surface, and the corner forming roller has the opening end portion. The molded part moves in a direction to approach the opening end of the substrate and moves the outer peripheral end molded part and the corner part molded part in a direction to approach the first rotation axis to move the open end molded part to the open end. It is made to contact | abut to a part.

  According to the present invention, the substrate rotates about the first rotation axis. The groove forming roller moves in a direction in which the groove forming portion approaches the first rotation shaft, contacts the outer peripheral surface, and presses the groove forming portion against the outer peripheral surface while rotating about the second rotation shaft. Thus, an annular groove is formed on the outer peripheral surface. At the same time, the corner portion forming roller moves in a direction in which the opening end portion forming portion approaches the opening end portion of the substrate, and the outer peripheral end portion forming portion and the corner portion forming portion approach the first rotating shaft. It moves in the direction and the opening end portion molding portion comes into contact with the opening end portion. At the same time, the outer peripheral end portion is in contact with the outer peripheral end portion on the opening end portion side, and at the same time, the corner portion is in contact with the corner portion and rotates around the third rotation axis as the opening end. The part molding part is pressed against the opening end. At the same time, the outer peripheral end molding portion is pressed against the outer end of the opening end. At the same time, the corner molding portion is pressed against the corner. Thereby, the opening end side outer peripheral end is formed, and the opening end is formed together with the opening end, and the corner is formed therewith.

  Here, in the front view with the first rotation axis as an axis, the opening end side outer peripheral end portion, the opening end portion, and the corner portion of the base material respectively form an outline line of the base material. ing. The corner forming roller abuts by moving the opening end forming portion in the direction approaching the opening end of the base material relative to the opening end and moving in the direction approaching the first rotation axis, The outer peripheral end molding portion abuts on the opening end side outer peripheral end by moving in the direction approaching the opening end portion of the base material and moving in the direction approaching the first rotation axis, and the corner molding portion Moves in a direction approaching the opening end of the base material and moves in a direction approaching the first rotation axis with respect to the corner portion. As a result, the corner forming roller makes line contact along the outer shape line of the base material, so that the load applied to the corner forming roller is reduced and the durability of the corner forming roller is improved. . Further, since the corner portion forming roller is pressed from the opening end portion and the outer peripheral surface to support the base material from the opening side, it is not necessary to support the bottom portion of the base material from the opening side. By eliminating the core pushing rod as in the prior art, the equipment cost and the maintenance cost can be reduced.

  In the present invention, the corner portion forming roller is brought into contact with the base material, and the corner portion forming roller is configured to form the opening end side outer peripheral end portion, the opening end portion and the corner portion, and the groove forming roller. It is preferable that the annular groove is formed on the groove forming roller without contacting the outer peripheral end portion on the opening end side. Since the outer peripheral end portion on the opening end side is not formed by the groove forming roller, the dimensional accuracy of the outer peripheral end portion on the opening end side and the opening end portion and the corner portion formed by the corner forming roller is good. To be kept.

  In the present invention, it is preferable that the corner portion forming roller has a symmetrical shape on one axial side and the other axial side from the axial center of the third rotation shaft. By using both the one axial side and the other axial side of the corner portion forming roller, the number of the corner portion forming rollers is halved, so that the equipment cost can be reduced.

  In the present invention, it is preferable that the groove forming roller has a symmetrical shape on one axial side and the other axial side from the axial center of the second rotation shaft. Since the groove forming roller uses both the one axial side and the other axial side, the number of the groove forming rollers is halved, so that the equipment cost can be reduced.

  In the present invention, it is preferable that the corner portion forming roller has a symmetrical shape on one axial side and the other axial side from the axial center of the third rotation shaft. By using both the one axial side and the other axial side of the corner portion forming roller, the number of the corner portion forming rollers is halved, so that the equipment cost can be reduced.

  The piston of the vehicle disc brake of the present invention has a bottomed cylindrical shape, and has an opening end, an outer peripheral surface, an inner peripheral surface, and a bottom, and an annular groove is formed at the outer peripheral end of the outer peripheral surface on the opening end side. A protrusion is formed at a position corresponding to the annular groove on the inner circumferential surface, and a corner between the outer circumferential end on the opening end side and the opening end has an R shape, and the opening The end portion side outer peripheral end portion, the opening end portion and the corner portion are continuous spinning surfaces.

  According to the present invention, since the opening end side outer peripheral end, the opening end, and the corner are a spinning processed surface, dimensional accuracy can be improved.

  According to the disclosed method of manufacturing a piston of a vehicle disc brake, the shape of the concave R-shaped corner portion formed on the corner portion forming roller is formed between the opening end side outer peripheral end portion and the opening end portion. Since it is transferred to the corners and molded into the desired convex R shape, there is no need to preform the shape with a narrowed opening as in the prior art, and the machining process can be reduced, thus reducing the machining cost. be able to. Further, even in a straight base material, the corner portion can be formed into a desired convex R shape by the corner portion forming roller. Further, since the corner portion forming roller acts to support the base material from the opening side, it is not necessary to support the bottom portion of the base material from the opening side. Therefore, the core pushing rod as in the prior art can be eliminated, and the operation of the core pushing rod becomes unnecessary, so that the cycle time can be shortened.

  According to the disclosed disc brake piston manufacturing apparatus for a vehicle, the corner forming roller makes line contact along the outer shape line of the base material, so that the load on the corner forming roller is reduced. The durability of the corner forming roller is improved. Further, since the corner portion forming roller is pressed from the opening end portion and the outer peripheral surface to support the base material from the opening side, it is not necessary to support the bottom portion of the base material from the opening side. By eliminating the core pushing rod as in the prior art, the equipment cost and the maintenance cost can be reduced.

  According to the piston of the disclosed disc brake for a vehicle, since the opening end side outer peripheral end, the opening end, and the corner are a spinning processed surface, dimensional accuracy can be improved.

FIG. 1 is a schematic configuration diagram showing a main part of a spinning device for a piston of a vehicle disc brake according to an embodiment of the present invention, and is a perspective view. FIG. 2A is a front view showing an example of a groove forming roller according to a spinning device for a piston of a vehicle disc brake according to the embodiment, and FIG. 2B relates to a spinning device for a piston of a vehicle disc brake according to the embodiment. It is a top view which shows the example of a groove forming roller. FIG. 3A is a front view showing an example of a corner forming roller according to a spinning device for a piston of a vehicle disc brake according to the embodiment, and FIG. 3B relates to a spinning device for a piston of a vehicle disc brake according to the embodiment. It is a top view which shows the example of a corner | angular part shaping | molding roller. FIG. 4 is a schematic structural view showing an example of a base material before spinning processing, and is a half sectional view. FIG. 5 is a schematic structural view showing an example of a piston of a vehicle disc brake according to the present invention, and is a half sectional view. FIG. 6 is a partially enlarged view of the piston. FIG. 7 is a schematic configuration diagram showing an operation when the substrate is spun by the spinning device for a piston of the vehicle disc brake according to the embodiment, and is a cross-sectional view showing a state immediately before spinning. FIG. 8 is a schematic configuration diagram showing a processing operation of spinning the base material by the spinning device for a piston of the vehicle disc brake of the embodiment, and is a cross-sectional view showing a state immediately after the spinning processing. FIG. 9 is a schematic configuration diagram illustrating an operation after the base material is spun by the spinning device for a piston of the vehicle disc brake according to the embodiment, and is a cross-sectional view showing a state immediately after the spinning processing.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a main part of a spinning processing apparatus 1 of the present embodiment, and is a perspective view. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiments, and the repetitive description thereof may be omitted.

  The spinning device 1 of the present embodiment is a spinning device 1 for a piston of a vehicle disc brake that spins a bottomed cylindrical base material 15 (hereinafter simply referred to as a spinning device 1). As an example, the base material 15 is a forged product made of carbon steel for machine structure or the like.

  As a specific configuration, the spinning apparatus 1 includes a rotating unit 2 that rotates around the first rotation axis P1 while holding the base material 15, and a second rotation axis P2 that is parallel to the first rotation axis P1. And a corner forming roller 4 that rotates together with the substrate 15 around the third rotation axis P3 that is perpendicular to the first rotation axis P1. . The third rotation axis P3 is in a position perpendicular to the second rotation axis P2. The groove forming roller 3 and the corner forming roller 4 are arranged at positions opposite to 180 [°] around the first rotation axis P1.

  The groove forming roller 3 processes the base material 15 by moving the second rotation axis P2 in the a1 direction to approach the first rotation axis P1.

  The corner forming roller 4 moves the third rotation axis P3 in the b1 direction approaching the rotation unit 2, and then moves the third rotation axis P3 in the a2 direction approaching the first rotation axis P1 to process the base material 15. . Alternatively, the corner forming roller 4 simultaneously moves in the b1 direction that brings the third rotation axis P3 closer to the rotation part 2 and the a2 direction that brings the third rotation axis P3 closer to the first rotation axis P1 to process the base material 15. To do.

  FIG. 2 is a view showing an example of the groove forming roller 3 according to the spinning processing apparatus 1, FIG. 2 (A) is a front view, and FIG. 2 (B) is a plan view. The groove forming roller 3 is made of a hard metal such as tool steel and has a rotationally symmetric cylindrical shape around the second rotation axis P2. In the groove forming roller 3, a flat part 31, a groove forming part 32, a flat part 33, a groove forming part 32, and a flat part 31 are formed in order from the side close to the rotating part 2. The groove forming roller 3 has a built-in bearing (not shown) and can be rotated by an external force. The groove forming part 32 has a cylindrical shape that is slightly larger than the flat part 31 and the flat part 33, and has a convex shape when viewed from the front.

  One side and the other side of the outer surface of the groove forming roller 3 are symmetrical with respect to a center line S1 orthogonal to the center of the second rotation axis P2. In FIG. 2A, one side and the other side are axisymmetric with respect to the center line S1. According to this, since both sides of the groove forming roller 3 can be used, the equipment cost can be reduced, and the number of groove forming rollers as consumable parts can be halved.

  FIG. 3 is a view showing an example of the corner forming roller 4 according to the spinning processing apparatus 1, FIG. 3 (A) is a front view, and FIG. 3 (B) is a plan view. The corner forming roller 4 is made of a hard metal such as tool steel and has a cylindrical shape that is rotationally symmetric about the third rotation axis P3. The corner portion forming roller 4 includes an opening end portion forming portion 41, a corner portion forming portion 47, an outer peripheral end portion forming portion 42, a corner portion forming portion 47, and an opening end portion forming portion 41 in order from the side closer to the first rotation axis P1. Is formed. The corner forming roller 4 has a built-in bearing (not shown) and can be rotated by an external force. The outer peripheral end molding part 42 has a cylindrical shape that is slightly larger than the opening end part molding part 41 and is convex in front view. The corner forming portion 47 has a concave R shape for forming the convex R-shaped corner portion 21 on the base material 15.

  One side and the other side of the outer surface of the corner forming roller 4 are symmetrical with respect to a center line S2 perpendicular to the axial center of the third rotation axis P3. In FIG. 3A, one side and the other side are axisymmetric with respect to the center line S2. According to this, since both sides of the corner portion forming roller 4 can be used, the equipment cost can be reduced, and the number of corner portion forming rollers as consumable parts can be halved.

  FIG. 4 is a schematic structural diagram showing an example of the base material 15 before the spinning process, and is a one-side sectional view. The base material 15 has a bottomed cylindrical shape. The base material 15 has a bottom portion 22, an inner bottom surface 55, an outer peripheral surface 18, and an inner peripheral surface 53. The base material 15 has an outer peripheral surface 18 that is straight when viewed from the front. There is an opening end 19 on the opening side, and an outer peripheral end 20 (opening end side outer peripheral end of the present application) on the opening end 19 side of the outer peripheral surface 18. A corner 21 is provided between the open end 19 and the outer peripheral end 20. Although the corner | angular part 21 is slightly convex R shape, it is not limited to this.

  FIG. 5 is a schematic structural diagram showing an example of the piston 5 of the present embodiment, and is a half sectional view. The piston 5 is obtained by spinning the base material 15 with the spinning machine 1. The piston 5 has a bottom portion 22, an inner bottom surface 55, an outer peripheral surface 18, and an inner peripheral surface 53. Then, an annular groove 54 is formed at the boundary between the outer peripheral surface 18 and the outer peripheral end 20.

  FIG. 6 is a partially enlarged view showing, in an enlarged manner, a portion surrounded by a one-dot chain line V in the piston 5 shown in FIG. The piston 5 is formed with a protrusion 59 at a position corresponding to the annular groove 54 on the inner peripheral surface 53. And the corner | angular part 21 between the opening edge part 19 and the outer peripheral edge part 20 is convex R shape. The detailed shape of the piston 5 will be described later.

  FIG. 7 is a schematic configuration diagram showing operations of the groove forming roller 3 and the corner forming roller 4 when the base material 15 is processed by the spinning processing apparatus 1 of the present embodiment, and shows a state immediately before the spinning processing. It is sectional drawing. FIG. 8 is a cross-sectional view showing a state immediately after the base material 15 has been subjected to the spinning process and when it becomes the piston 5. FIG. 9 is a schematic configuration diagram showing the operation of the groove forming roller 3 and the corner forming roller 4 after spinning the base material 15, and a cross-sectional view showing a state immediately after the piston 5 is formed.

  Based on FIGS. 7-9, the manufacturing procedure of piston 5 is demonstrated below.

  First, the outer peripheral surface 18 of the base material 15 is gripped by the chuck mechanism provided in the rotating unit 2, and the rotating unit 2 rotates around the first rotation axis P <b> 1 with the base material 15 gripped. At that time, the rotating unit 2 rotates while holding the base material 15 without supporting the bottom portion 22 of the base material 15 from the opening side. The rotating unit 2 rotates about the first rotation axis P1 in the direction of an arrow c1 that is clockwise in a plan view, for example. The groove forming roller 3 and the corner forming roller 4 are disposed at positions opposite to 180 [°] with the first rotation axis P1 as an intermediate position.

  The corner forming roller 4 moves the opening end forming portion 41 toward the opening end 19 of the substrate 15 in the b1 direction to bring the opening end forming portion 41 into contact with the opening end 19 of the substrate 15. By rotating together with the material 15, it rotates in the direction of the arrow d1 which is counterclockwise when viewed from the groove forming roller 3 side. Then, while co-rotating with the base material 15, the open end molding part 41 and the outer peripheral end molding part 42 are moved in the direction a <b> 2 approaching the first rotation axis P <b> 1 to move the open end molding part 41 to the base 15. The opening end 19 and the outer peripheral end 20 on the side of the opening end 19 are formed on the substrate 15 by pressing the outer end forming part 42 against the outer peripheral surface 18 at the same time. At the same time, the corner portion 21 of the base material 15 is convex R by transferring the concave R shape of the corner portion molding portion 47 formed on the corner portion molding roller 4 to the corner portion 21 between the opening end portion 19 and the outer peripheral end portion 20. The shape. Here, the opening end portion forming portion 41 presses the outer peripheral end portion 20 closer to the first rotation axis P1 by the dimensional difference ΔH than the outer peripheral surface 18.

  Alternatively, the corner portion forming roller 4 moves in the b1 direction in which the opening end portion forming portion 41 is brought closer to the opening end portion 19 of the base material 15, and the opening end portion forming portion 41 and the outer peripheral end portion forming portion 42 are moved to the first rotating shaft. It moves in the a2 direction approaching P1 to bring the open end molding part 41 into contact with the open end 19 of the base material 15 and the outer peripheral end molding part 42 into contact with the outer peripheral surface 18 to rotate together with the base material 15. Thus, it rotates in the direction of the arrow d1 that is counterclockwise when viewed from the groove forming roller 3 side. And while rotating together with the base material 15, the corner forming roller 4 moves simultaneously in the b1 direction and the a2 direction, and presses the opening end portion forming portion 41 against the opening end portion 19 of the base material 15, so that the outer peripheral end portion is pressed. By pressing the molding portion 42 against the outer peripheral surface 18, the opening end 19 and the outer peripheral end 20 on the opening end 19 side are formed on the base material 15, and the corner forming portion formed on the corner forming roller 4. The concave portion R of 47 is transferred to the corner portion 21 of the opening end portion 19 and the outer peripheral end portion 20 to make the corner portion 21 of the base material 15 have a convex R shape. Here, the opening end portion forming portion 41 presses the outer peripheral end portion 20 closer to the first rotation axis P1 by the dimensional difference ΔH than the outer peripheral surface 18. In addition to the above, the corner forming roller 4 may move in the b1 direction after moving in the a2 direction.

  After the corner forming roller 4 is in contact with the base material 15 and the opening end portion 19, the outer peripheral end portion 20 and the corner portion 21 are formed, the groove forming roller 3 moves the convex groove forming portion 32 to the first rotation axis P1. The groove forming portion 32 moves in the a1 direction approaching to the outer peripheral surface 18 of the base material 15 and rotates in the direction of the arrow c2 that rotates together with the base material 15 and is counterclockwise in plan view. And while rotating together with the base material 15, the annular groove 54 is formed by pressing the convex groove forming portion 32 against the outer peripheral surface 18. Here, when pressing the groove forming portion 32 against the outer peripheral surface 18, the flat portion 33 and the outer peripheral end portion 20 are not in contact with each other and have a gap ΔH ′. When the annular groove 54 is formed, the corner portion forming roller 4 is further moved in the b1 direction to press the opening end portion 19, the outer peripheral end portion 20 and the corner portion 21, thereby forming the piston 5 to a desired size.

  Then, after the piston 5 is molded, the groove forming roller 3 moves away from the base material 15 by moving the convex groove forming portion 32 in the a2 direction away from the first rotation axis P1. In addition, the corner forming roller 4 moves the opening end forming portion 41 in the b2 direction away from the opening end 19 of the base material 15 and moves the opening end forming portion 41 and the outer end forming portion 42 to the first rotating shaft. It moves in the a1 direction away from P1 and retreats from the base material 15. In addition to the above, the corner forming roller 4 may move in the a1 direction after moving in the b2 direction, and may move in the b2 direction after moving in the a1 direction. According to the present embodiment, the conventional operation of the core pushing rod (the step of supporting with the core pushing rod before processing and the step of releasing the support of the core pushing rod after machining) becomes unnecessary, and the cycle time is shortened. be able to. The corner forming roller 4 is brought into contact with the base material 15 before the groove forming roller 3 to form the outer peripheral end 20, the open end 19 and the corner 21, and then the groove forming roller 3 is connected to the annular groove 54. When the outer peripheral surface 18 is formed, the outer peripheral end 20, the open end 19, and the corner 21 do not contact the groove forming roller 3, so that the outer peripheral end 20 and the opening are not affected by the groove forming roller 3. The dimensional accuracy of the end 19 and the corner 21 can be kept good.

  By these spinning processes of this embodiment, the piston 5 is formed into a desired shape.

  According to this embodiment, it is not necessary to perform preforming in a state in which the opening is narrowed as in the prior art, the processing steps can be reduced, and processing costs can be reduced. Further, also in the base 15 of the straight forged product, a desired convex R-shaped corner 21 can be formed on the corner 21 by the corner forming roller 4. Further, since the corner forming roller 4 is in line contact along the outer shape line of the base material 15, the load applied to the corner forming roller 4 is reduced, and the durability of the corner forming roller 4 is improved. And since the effect | action which supports the base material 15 from the opening side works by the corner | angular part shaping | molding roller 4, a core pushing rod like a prior art can be eliminated, and since operation | movement of a core pushing rod becomes unnecessary, cycle time is reduced. It can be shortened. Moreover, since it is the structure which supports the base material 15 from the opening side with the corner | angular part shaping | molding roller 4, a core pushing rod like a prior art can be eliminated and an installation cost and a maintenance cost can be reduced.

  According to the present embodiment, since the piston 5 is a spinning processed surface in which the opening end portion 19, the outer peripheral end portion 20, and the corner portion 21 are continuous, it is possible to improve the dimensional accuracy.

  As shown in FIGS. 7 and 8, the opening end forming portion 41 of the corner forming roller 4 is rotated by the first rotation of the opening end forming portion 41 when the corner forming roller 4 comes into contact with the base material 15. The length L1 in the direction of the axis P1 is provided to be larger than the thickness T2 of the opening end 19 in the piston 5.

  The outer peripheral end molding portion 42 in the corner molding roller 4 has a size exceeding the opening end 19 side of the annular groove 54 in the piston 5 when the corner molding roller 4 contacts the base material 15. In addition, the piston 5 does not reach the inner bottom surface 55 side of the annular groove 54 in the piston 5.

  As shown in FIGS. 5 and 6, the piston 5 has a protrusion 59 formed at a position corresponding to the annular groove 54 on the inner peripheral surface 53.

  In the piston 5, the inner peripheral surface 53 on the opening end 19 side has a first R (R shape) 61 on the inner bottom surface 55 side in the projecting portion 59 and a second R (R) on the opening end 19 side. (Shape) 62 and smoothly connected.

  In the piston 5, the thickness T <b> 2 of the opening end 19 is formed to be larger than the thickness T <b> 1 of the outer peripheral surface 18. According to this configuration, the area of the open end 19 that receives external force from the external friction pad that contacts the open end 19 can be sufficiently increased, and the durability is further improved. In the piston 5, the outer peripheral surface 18 and the outer peripheral end 20 have a dimensional difference ΔH.

  The piston 5 thus spun has achieved a reduction in weight while ensuring mechanical strength as compared with a known machined product. The piston 5 is appropriately finished with a surface treatment such as hard chrome plating.

  The present invention is not limited to the embodiment described above, and various modifications can be made without departing from the present invention. For example, the dimensions of each part of the piston 5 can be appropriately changed according to the specifications of the boots to be combined and the external friction pads to be abutted, while ensuring the mechanical strength. Further, for example, in the above-described embodiment, the groove forming roller 3 and the corner portion forming roller 4 are symmetrical outer surfaces on one side and the other side. In some cases, either or both of the forming rollers 4 may be formed as outer surfaces having an asymmetric shape on one side and the other side.

DESCRIPTION OF SYMBOLS 1 Spinning apparatus 2 Rotating part 3 Groove forming roller 4 Corner part forming roller 5 Piston 15 Base material 18 Outer peripheral surface 19 Open end 20 Open end side outer peripheral end (outer peripheral end)
21 corner portion 22 bottom portion 32 groove forming portion 41 opening end portion forming portion 42 outer peripheral end portion forming portion 47 corner portion forming portion 53 inner peripheral surface 54 annular groove 55 inner bottom surface 59 projecting portion P1 first rotating shaft P2 second rotating shaft P3 Third rotation axis T1, T2

Claims (8)

A method of manufacturing a piston of a vehicle disc brake by spinning,
Rotate the bottomed cylindrical substrate,
By pressing a groove forming roller having a convex groove forming portion from the outer peripheral surface of the base material, an annular groove is formed on the outer peripheral surface,
An outer peripheral end molding portion in contact with the opening end side outer peripheral end portion of the base material, an open end portion molding portion in contact with the opening end portion of the base material, the opening end portion outer peripheral end portion, and the opening end portion. By pressing a corner forming roller provided with an R-shaped corner forming portion for forming a corner between the opening end and the outer peripheral surface, the opening end side outer peripheral end and the opening An end part and a corner part are formed, A manufacturing method of a piston of a disc brake for vehicles. In the manufacturing method of the piston of the disc brake for vehicles according to claim 1,
After the corner portion forming roller abuts on the base material, and the corner portion forming roller forms the opening end side outer peripheral end portion and the opening end portion and the corner portion,
A method of manufacturing a piston for a vehicle disc brake, wherein the groove forming roller forms the annular groove without the groove forming roller coming into contact with the outer peripheral end on the opening end side. In the manufacturing method of the piston of the disc brake for vehicles according to claim 1 or 2,
Manufacturing of a piston for a vehicle disc brake, wherein the bottom of the base material is supported from the outer peripheral surface side without being supported from the opening side, and the base material is formed by the groove forming roller and the corner portion forming roller. Method. In a spinning device for a piston of a vehicle disc brake,
A rotating part that rotates the base material around the first rotation axis while supporting from the outer peripheral surface without supporting the bottom of the bottomed cylindrical base material from the opening side;
A cylindrical groove forming roller provided with a convex groove forming portion for rotating around the second rotation shaft as an axis and forming an annular groove on the outer peripheral surface of the base material;
Rotating around the third rotation axis as an axis, forming an outer peripheral end portion for forming the outer peripheral end portion on the opening end side of the base material, and forming an open end portion for forming the open end portion of the base material A cylindrical corner forming roller provided with a portion and an R-shaped corner forming portion for forming a corner between the opening end side outer peripheral end and the opening end,
The second rotation axis is in a direction parallel to the first rotation axis, the third rotation axis is in a direction orthogonal to the first rotation axis, and
The groove forming roller moves the groove forming portion closer to the first rotation shaft to bring the groove forming portion into contact with the outer peripheral surface,
The corner portion forming roller moves in a direction to bring the opening end portion forming portion closer to the opening end portion, and moves in a direction to bring the outer peripheral end portion forming portion and the corner portion forming portion closer to the first rotation shaft. A spinning device for a piston of a vehicular disc brake, wherein an end molding portion is brought into contact with the opening end. In the spinning device of the piston of the vehicle disc brake according to claim 4,
The corner portion forming roller is brought into contact with the substrate, and the corner portion forming roller is configured to form the opening end side outer peripheral end portion, the opening end portion and the corner portion,
A spinning device for a piston of a vehicular disc brake, wherein the groove forming roller forms the annular groove without bringing the groove forming roller into contact with the outer peripheral end of the opening end. In the spinning device of the piston of the disc brake for vehicles according to claim 4 or 5,
The groove forming roller is a spinning device for a piston of a vehicular disc brake, wherein one axial side and the other axial side are symmetrical from the axial center of the second rotating shaft. In the spinning device of the piston of the disc brake for vehicles according to claim 4 or 5,
The corner part forming roller is a spinning device for a piston of a vehicular disc brake, wherein one axial side and the other axial side are symmetrical from the axial center of the third rotating shaft. It has a bottomed cylindrical shape, has an open end, an outer peripheral surface, an inner peripheral surface, and a bottom,
An annular groove is formed at the outer peripheral end of the outer peripheral surface on the opening end side,
A protrusion is formed at a position corresponding to the annular groove on the inner peripheral surface,
The corner between the opening end side outer peripheral end and the opening end is R-shaped,
The piston of a vehicle disc brake, wherein the opening end side outer peripheral end, the opening end and the corner are continuous spinning surfaces.

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