Manufacturing device and manufacturing method of piston unit

Abstract

To provide a technique which can suppress the misalignment between an axial center of a piston and an axial center of a piston shoe when connecting the piston and the piston shoe.SOLUTION: A manufacturing device 10 comprises: a support part 18 for supporting a piston shoe 2; a pressing part 20 for pressing a piston 1 downward; a first roller 24; a pair of second rollers 26; a drive mechanism 56 for rotationally driving the pair of second rollers 26; and a moving mechanism 28 for moving the first roller 24 and the pair of second rollers 26. The moving mechanism 28 makes a first pressing face 24b contact with a corner part of an upper end part of a holding part 2b of the piston shoe 2 by moving the first roller 24, and makes a second pressing face 26b contact with the corner part of the upper end part of the holding part 2b by moving the pair of second rollers 26 to a side opposite to the first roller 24.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an apparatus and method for manufacturing a piston unit. [Background technology]

[0002] Conventionally, in a swash plate type piston pump or piston motor, a piston shoe is used to support a piston. For example, a piston pump disclosed in Patent Document 1 includes a cylinder block that rotates together with a shaft, a plurality of cylinders formed in the cylinder block, a piston slidably inserted in each cylinder, a piston shoe that supports the tip of the piston, and a swash plate that contacts the piston shoe.

[0003] The swash plate is inclined relative to the rotation axis (shaft) of the cylinder block. When the cylinder block rotates, the piston shoes slide against the swash plate and move in the rotation direction of the cylinder block, causing the pistons to move in the axial direction of the cylinders.

[0004] To achieve the above-mentioned piston operation, the tip of the piston is supported by a piston shoe so that it can swing. Figure 1 is a schematic diagram showing an example of a piston and a piston shoe. In Figure 1, the piston shoe 2 is shown in half cross section to make it easier to understand the connection state between the piston 1 and the piston shoe 2.

[0005] The piston 1 shown in Fig. 1 has a columnar (cylindrical or cylindrical) main body 1a and a connecting portion 1b having a spherical crown-shaped outer peripheral surface. The piston shoe 2 has a plate-shaped portion 2a that slides against a swash plate (not shown) when the piston pump operates, and a cylindrical holding portion 2b that holds the connecting portion 1b of the piston 1. The inner peripheral surface of the holding portion 2b has a spherical crown shape corresponding to the connecting portion 1b so that the connecting portion 1b can be slidably held. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-042704 Summary of the Invention [Problem to be solved by the invention]

[0007] Generally, when connecting the piston 1 and the piston shoe 2, first, the connecting portion 1b of the piston 1 is fitted into the holding portion 2b of the piston shoe 2, as shown in Fig. 2. Then, as shown by the arrow in Fig. 2(b), the upper portion of the holding portion 2b is pressed from the side, thereby crimping the upper portion of the holding portion 2b against the connecting portion 1b. This prevents the connecting portion 1b from coming off the holding portion 2b, and the piston 1 and the piston shoe 2 are connected. In this specification, the piston 1 and the piston shoe 2 in the connected state are referred to as a piston unit 3.

[0008] Incidentally, when the upper part of the retaining portion 2b is pressed from the side to be crimped as shown by the arrow in Fig. 2(b), the piston shoe 2 is pressed to the side, which tends to cause the axis of the piston 1 to become misaligned with the axis of the piston shoe 2. If the piston 1 and the piston shoe 2 are connected in a state in which the axis of the piston 1 and the axis of the piston shoe 2 are misaligned, there are cases in which the connecting portion 1b cannot swing smoothly relative to the retaining portion 2b.

[0009] Therefore, an object of the present invention is to provide a technique capable of suppressing misalignment of the axes of a piston and a piston shoe when they are connected to each other. [Means for solving the problem]

[0010] The present invention relates to an apparatus and method for manufacturing a piston unit as described below.

[0011] (1) An apparatus for manufacturing a piston unit by connecting a piston having a columnar body and a spherical crown-shaped connecting portion provided at the tip of the body to a piston shoe having a cylindrical holding portion having a spherical crown-shaped inner surface, a support portion that supports the piston shoe from below so that the holding portion opens upward; a pressing portion that presses the main body portion of the piston downward in a state in which the connecting portion of the piston is fitted into the holding portion of the piston shoe; a first roller having a first pressing surface that presses the holding portion of the piston shoe and is rotatable about a first axis extending in a vertical direction; a pair of second rollers each having a second pressing surface that presses against the holding portion of the piston shoe and being rotatable about a second axis extending in the vertical direction; a drive source that rotates the first roller or the pair of second rollers; a moving mechanism for moving the first roller and the pair of second rollers in a horizontal direction, the first pressing surface and the second pressing surface have a circular shape in a cross section parallel to a horizontal direction, and are formed so that a diameter of the cross section increases toward an upper side, The moving mechanism moves the first roller in a first direction parallel to the horizontal direction to bring the first pressing surface into contact with a corner of an upper end of the holding portion, and moves the pair of second rollers in a second direction opposite to the first direction to bring the second pressing surface into contact with the corner of an upper end of the holding portion.

[0012] (2) The manufacturing apparatus for a piston unit according to (1) above, wherein the driving source drives the pair of second rollers to rotate.

[0013] (3) The manufacturing apparatus for a piston unit described in (1) or (2) above, wherein the moving mechanism brings the first roller into contact with the holding portion and then brings the pair of second rollers into contact with the holding portion.

[0014] (4) A manufacturing apparatus for a piston unit described in any one of (1) to (3) above, wherein the inclination angle of the second pressing surface with respect to the horizontal direction in a cross section passing through the second axis and parallel to the second axis is 45° or less.

[0015] (5) A manufacturing apparatus for a piston unit described in any one of (1) to (4) above, wherein the first pressing surface is curved in an arc shape in a cross section passing through the first axis and parallel to the first axis.

[0016] (6) A method for manufacturing a piston unit by connecting a piston having a columnar body and a spherical crown-shaped connecting portion provided at a tip of the body to a piston shoe having a cylindrical holding portion having a spherical crown-shaped inner surface, the method comprising the steps of: The piston shoe is supported from below so that the holding portion opens upward, pressing the body portion of the piston downward with the connecting portion of the piston fitted in the holding portion of the piston shoe; Rotating a first roller that rotates about a first axis extending in the vertical direction or a pair of second rollers that rotate about a second axis extending in the vertical direction, The first roller and the pair of second rollers are moved in a horizontal direction; The holding portion of the piston shoe is pressed by a first pressing surface of the first roller and a second pressing surface of the pair of second rollers; the first pressing surface and the second pressing surface have a circular shape in a cross section parallel to a horizontal direction, and are formed so that a diameter of the cross section increases toward an upper side, A manufacturing method for a piston unit, wherein, when moving the first roller and the pair of second rollers in a horizontal direction, the first roller is moved in a first direction parallel to the horizontal direction to bring the first pressing surface into contact with a corner of an upper end portion of the holding portion, and the pair of second rollers are moved in a second direction opposite to the first direction to bring the second pressing surface into contact with a corner of an upper end portion of the holding portion.

[0017] (7) The method for manufacturing a piston unit according to (6) above, further comprising rotating the pair of second rollers.

[0018] (8) A method for manufacturing a piston unit described in (6) or (7) above, in which, when moving the first roller and the pair of second rollers horizontally, the first roller is brought into contact with the holding portion, and then the pair of second rollers are brought into contact with the holding portion.

[0019] (9) A method for manufacturing a piston unit described in any of (6) to (8) above, wherein the inclination angle of the second pressing surface with respect to the horizontal direction in a cross section passing through the second axis and parallel to the second axis is 45° or less.

[0020] (10) A method for manufacturing a piston unit described in any one of (6) to (9) above, wherein the first pressing surface is curved in an arc shape in a cross section passing through and parallel to the first axis. Effect of the Invention

[0021] According to the present invention, it is possible to prevent the axes of the piston and the piston shoe from being misaligned when they are connected to each other. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 is a schematic diagram showing an example of a piston and a piston shoe. [Diagram 2] FIG. 2 is a diagram showing an example of a method for connecting a piston and a piston shoe. [Diagram 3] FIG. 3 is a schematic diagram showing a manufacturing apparatus for a piston unit according to one embodiment of the present invention. [Figure 4] FIG. 4 is an enlarged end view showing the AA cut portion of FIG. [Diagram 5] FIG. 5 is a schematic view showing the vicinity of the upper end portion of the first support member. [Figure 6] FIG. 6 is a diagram for explaining the operation of the manufacturing apparatus. [Figure 7]FIG. 7 is a diagram for explaining the operation of the manufacturing apparatus. [Figure 8] FIG. 8 is a diagram for explaining the operation of the manufacturing apparatus. [Figure 9] FIG. 9 is a diagram for explaining the operation of the manufacturing apparatus. [Figure 10] FIG. 10 is a diagram for explaining the operation of the manufacturing apparatus. [Figure 11] FIG. 11 is a diagram for explaining the operation of the manufacturing apparatus. [Figure 12] FIG. 12 is a diagram for explaining the operation of the manufacturing apparatus. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Hereinafter, a manufacturing apparatus and a manufacturing method for a piston unit according to an embodiment of the present invention will be described.

[0024] (Configuration of manufacturing equipment) Fig. 3 is a schematic diagram showing a manufacturing apparatus for a piston unit according to an embodiment of the present invention, where (a) is a plan view of the manufacturing apparatus and (b) is a front view of the manufacturing apparatus. Fig. 4 is an enlarged end view showing an AA cut portion in Fig. 3(a). In the following, a case of manufacturing the piston unit 3 shown in Figs. 1 and 2 will be described.

[0025] 3, the manufacturing apparatus 10 for the piston unit according to this embodiment has a pedestal 12 having a rectangular shape in a plan view. In the following description, the direction along the long side of the pedestal 12 in a plan view is referred to as the length direction X of the manufacturing apparatus 10, and the direction along the short side of the pedestal 12 is referred to as the width direction Y of the manufacturing apparatus 10.

[0026] As shown in FIG. 3, a pair of support plates 14 are fixed on the base 12. As shown in FIG. 3(a), the pair of support plates 14 are provided along the length direction X of the manufacturing apparatus 10 and spaced apart from each other in the width direction Y. A pair of holding members 16 are fixed to each support plate 14. Each holding member 16 is fixed to the support plate 14 so as to protrude from the support plate 14 to the inside in the width direction Y of the manufacturing apparatus 10. Also, as shown in FIG. 3(a) and FIG. 4, a guide groove 16a is formed in each holding member 16 so as to open toward the inside in the width direction Y of the manufacturing apparatus 10 and extend in the length direction X.

[0027] 3, a support portion 18 that supports the piston shoe 2 is provided on the base 12 between the pair of support plates 14. The support portion 18 has a cylindrical first support member 80 and a second support member 82 that supports the first support member 80. In this embodiment, the second support member 82 supports the first support member 80 rotatably around an axis that extends in the vertical direction.

[0028] FIG. 5 is a schematic diagram showing the vicinity of the upper end of the first support member 80. Note that FIG. 5 shows a cross section of the piston shoe 2 and the first support member 80 cut in half. As shown in FIG. 5, a recess 80a is formed at the upper end of the first support member 80 into which the plate-shaped portion 2a of the piston shoe 2 is fitted. In this embodiment, the plate-shaped portion 2a has a disk shape. The recess 80a has a circular cross section corresponding to the plate-shaped portion 2a. In this embodiment, the first support member 80 supports the piston shoe 2 from below so that the holding portion 2b of the piston shoe 2 opens upward.

[0029] As shown in Fig. 3(b) and Fig. 5, a rod-shaped pressing part 20 is provided above the support part 18. As shown in Fig. 3(b), the pressing part 20 is supported by a support unit 22 so as to be movable in the vertical direction and rotatable around an axis. In order to avoid complicating the drawing, the piston 1, the pressing part 20, and the support unit 22 are omitted in Fig. 3(a). Similarly, the piston 1, the pressing part 20, and the support unit 22 are omitted in Fig. 6(a), Fig. 7(a), Fig. 8(a), and Fig. 10(a) described later.

[0030] In this embodiment, the support unit 22 has a support plate 22a supported by the pair of support plates 14, and a cylindrical holding member 22b fixed to the support plate 22a. In this embodiment, the pressing part 20 is held by the holding member 22b so as to be movable in the vertical direction and rotatable around an axis.

[0031] 5, in this embodiment, when the piston 1 and the piston shoe 2 are connected, the pressing portion 20 presses the main body portion 1a of the piston 1 downward. In this embodiment, the main body portion 1a of the piston 1 has a cylindrical shape with an open upper end (the end opposite the connecting portion 1b). The tip portion 20a of the pressing portion 20 has a columnar shape, and is inserted into the upper end of the main body portion 1a when the pressing portion 20 presses the piston 1 downward.

[0032] 3, in the longitudinal direction X of the manufacturing apparatus 10, a first roller 24 is provided on one side of the support portion 18, and a pair of second rollers 26 are provided on the other side of the support portion 18. The first roller 24 and the second roller 26 will be described in detail later.

[0033] A movement mechanism 28 is provided so as to be supported by the pair of support plates 14. The first roller 24 and the pair of second rollers 26 are supported by the movement mechanism 28 so as to be movable in the horizontal direction (in this embodiment, the length direction X). In this embodiment, the movement mechanism 28 has a first slide unit 30, a second slide unit 32, and a drive mechanism 38.

[0034] Although details will be described later, the first slide unit 30 is supported by the pair of support plates 14 so as to be movable in the length direction X relative to the pair of support plates 14. Moreover, the second slide unit 32 is supported by the first slide unit 30 so as to be movable in the length direction X relative to the first slide unit 30. The first slide unit 30 and the second slide unit 32 will be described in detail below.

[0035] The first slide unit 30 includes a frame unit 34 and a drive mechanism 36. The frame unit 34 includes a pair of support plates 40, a pair of outer guide rails 42, a pair of inner guide rails 44, a connecting plate 46, a connecting plate 48, a roller support member 50, a pair of support plates 52, and a support plate 54.

[0036] The pair of support plates 40 are provided inside the pair of support plates 14 in the width direction Y. The pair of support plates 40 are provided to extend in the length direction X along the pair of support plates 14. An outer guide rail 42 and an inner guide rail 44 are provided on each support plate 40. The outer guide rail 42 is provided to protrude outward from the support plate 40 in the width direction Y and extend in the length direction X, and the inner guide rail 44 is provided to protrude inward from the support plate 40 in the width direction Y and extend in the length direction X.

[0037] 3(a) and 4, the outer guide rail 42 is slidably fitted into the guide groove 16a of the holding member 16. This allows the outer guide rail 42 to move in the length direction X relative to the holding member 16. In other words, the first slide unit 30 is movable in the length direction X relative to the pair of support plates 14. The inner guide rail 44 will be described later.

[0038] The connecting plate 46 is fixed to the upper end surfaces of the pair of support plates 40 so as to connect one end of the pair of support plates 40 in the longitudinal direction X. The driving mechanism 36 is fixed to the lower surface of the connecting plate 46. The driving mechanism 36 will be described later.

[0039] The connecting plate 48 is fixed to the pair of support plates 40 so as to connect the other ends of the pair of support plates 40 in the longitudinal direction X. The roller support member 50 is fixed to the connecting plate 48 so as to protrude from the connecting plate 48 to one side in the longitudinal direction X. As shown in Fig. 3(b) , in this embodiment, the roller support member 50 has an inverted C-shape when viewed from the front.

[0040] As shown in FIGS. 3(a) and 3(b), the roller support member 50 rotatably supports a pair of second rollers 26. Each second roller 26 has a cylindrical rotating shaft 26a extending in the vertical direction. Each second roller 26 is supported by the roller support member 50 so as to be rotatable about the rotating shaft 26a. In this embodiment, the pair of second rollers 26 are arranged side by side in the width direction Y. More specifically, the pair of second rollers 26 are supported by the roller support member 50 so that the second rollers 26 are located on one side and the other side of the first support member 80 in the width direction Y. In this embodiment, the axis of the rotating shaft 26a corresponds to the second axis.

[0041] The pair of support plates 52 are fixed to the connecting plate 48 so as to extend from both ends of the connecting plate 48 in the width direction Y to the other side in the length direction X. The support plate 54 is fixed to the upper end surfaces of the pair of support plates 52 so as to connect the pair of support plates 52. A drive mechanism 56 for driving and rotating the pair of second rollers 26 is provided on the support plate 54. Although detailed description will be omitted, the drive mechanism 56 is composed of a motor, a gear box, and the like. In this embodiment, the drive mechanism 56 corresponds to a drive source that drives and rotates the pair of second rollers 26.

[0042] The output shaft 56a of the drive mechanism 56 is provided so as to penetrate the support plate 54. The rotation of the output shaft 56a is transmitted to the rotation shaft 26a of each of the second rollers 26 via a plurality of gears 58a, 58b. This causes the pair of second rollers 26 to rotate. Note that the configuration for transmitting the rotation of the output shaft 56a to the second rollers 26 is not limited to the above example, and various known configurations of rotation transmission mechanisms can be used.

[0043] The driving mechanism 36 has a rod 36a provided so as to be movable forward and backward in the length direction X. In this embodiment, the driving mechanism 36 has the rod 36a, a cylinder body 36b that holds the rod 36a so as to be movable forward and backward, and a servo motor 36c that moves the rod 36a forward and backward. In this embodiment, the cylinder body 36b of the driving mechanism 36 is fixed to a connecting plate 46. Note that various electric cylinders can be used as the driving mechanism 36, and detailed description thereof will be omitted.

[0044] The driving mechanism 38 has a rod 38a that can advance and retreat in the length direction X. Although detailed description will be omitted, an electric cylinder can be used as the driving mechanism 38, similar to the driving mechanism 36. The driving mechanism 38 is supported on the base 12 via a support plate 60. In this embodiment, the driving mechanism 38 is provided on the other side of the connecting plate 48 in the length direction X so that the tip of the rod 38a can push the connecting plate 48 to one side in the length direction X. Note that the tip of the rod 38a is not connected to the connecting plate 48, but is simply in contact with the connecting plate 48.

[0045] As shown in FIG. 3(a), the driving mechanism 62 is provided so as to be aligned with the driving mechanism 36 in the width direction Y. In order to avoid cluttering the drawing, the driving mechanism 62 is omitted from FIG. 3(b). The driving mechanism 62 has a rod 62a that can advance and retreat in the length direction X. Although detailed explanation is omitted, an electric cylinder can be used as the driving mechanism 62, similar to the driving mechanism 36. The driving mechanism 62 is supported by the base 12 via a support plate 64. In this embodiment, the driving mechanism 62 is provided on one side of the frame unit 34 in the length direction X so that the tip of the rod 62a can push the frame unit 34 to the other side in the length direction X.

[0046] The second slide unit 32 has a pair of support plates 66, a connecting plate 68, a roller support member 70, and a plurality of holding members 72. The pair of support plates 66 are provided inside the pair of support plates 40 in the width direction Y. The pair of support plates 66 are provided so as to extend in the length direction X along the pair of support plates 40.

[0047] The connecting plate 68 is fixed to the pair of support plates 66 so as to connect the other ends of the pair of support plates 66 in the longitudinal direction X. A tip end of the rod 36a of the drive mechanism 36 is fixed to one side of the connecting plate 68 in the longitudinal direction X.

[0048] The roller support member 70 is fixed to the connecting plate 68 so as to protrude from the connecting plate 68 to the other side in the longitudinal direction X. As shown in Fig. 3(b) , in this embodiment, the roller support member 70 has a C-shape when viewed from the front.

[0049] As shown in FIGS. 3(a) and 3(b), the roller support member 70 rotatably supports the first roller 24. The first roller 24 has a cylindrical rotating shaft 24a extending in the vertical direction. The first roller 24 is supported by the roller support member 70 so as to rotate around the rotating shaft 24a as a rotation center. In this embodiment, in a plan view, the first roller 24 and the first support member 80 are positioned in a straight line (not shown) extending in the length direction X. In addition, the first roller 24 is positioned between the pair of second rollers 26 in the width direction Y. In this embodiment, the axis of the rotating shaft 24a corresponds to the first axis.

[0050] Each holding member 72 is fixed to the support plate 66 so as to protrude outward from the support plate 66 in the width direction Y. In this embodiment, a pair of holding members 72 is fixed to each support plate 66. As shown in Figures 3(a) and 4, a guide groove 72a is formed in each holding member 72 so as to open toward the outside in the width direction Y and extend in the length direction X.

[0051] The inner guide rails 44 of the first slide unit 30 are slidably fitted into the guide grooves 72a of each holding member 72. This allows the inner guide rails 44 to move in the length direction X relative to the holding members 72. In other words, the second slide unit 32 is movable in the length direction X relative to the pair of support plates 40 of the first slide unit 30.

[0052] (Manufacturing equipment operation) Next, a description will be given of the operation of the manufacturing apparatus 10. Note that Fig. 3 shows the manufacturing apparatus 10 before starting its operation.

[0053] When manufacturing the piston unit 3, as shown in Figs. 3 and 5, a worker first installs the piston shoe 2 on the support portion 18. Specifically, the worker fits the plate-shaped portion 2a of the piston shoe 2 into the recess 80a of the first support member 80. The worker also fits the connecting portion 1b of the piston 1 into the holding portion 2b of the piston shoe 2. After that, the worker inserts the tip portion 20a of the pressing portion 20 into the upper end portion of the main body portion 1a of the piston 1. As a result, the pressing portion 20 presses the piston 1 downward.

[0054] Next, the operator starts the manufacturing apparatus 10 by operating a start button (not shown). As shown in FIG. 6, when the manufacturing apparatus 10 starts, first, the rod 38a of the drive mechanism 38 extends to one side in the longitudinal direction X and pushes the connecting plate 48 of the first slide unit 30 to one side in the longitudinal direction X. As a result, the first slide unit 30 moves to one side in the longitudinal direction X relative to the pair of support plates 14. In this embodiment, the first slide unit 30 moves to a position where the pair of second rollers 26 are close to the piston shoe 2. Note that in the state shown in FIG. 6, the pair of second rollers 26 are not in contact with the piston shoe 2.

[0055] In this embodiment, the second slide unit 32 moves together with the first slide unit 30 to one side in the longitudinal direction X. Also, the rod 62a of the drive mechanism 62 retracts to one side in the longitudinal direction X as the first slide unit 30 moves.

[0056] Next, as shown in Fig. 7, the rod 36a of the drive mechanism 36 extends to the other side in the longitudinal direction X and pushes the connecting plate 68 of the second slide unit 32 to the other side in the longitudinal direction X. This causes the second slide unit 32 to move to the other side in the longitudinal direction X relative to the pair of inner guide rails 44 of the first slide unit 30. In this embodiment, the second slide unit 32 moves to a position where the first roller 24 is close to the piston shoe 2. Note that in the state shown in Fig. 7, the first roller 24 is not in contact with the piston shoe 2.

[0057] In this embodiment, as shown in Fig. 7, after the first roller 24 is brought close to the piston shoe 2, the movement of the rod 36a is temporarily stopped, and the movement of the first roller 24 to the other side in the longitudinal direction X is stopped. In this state, the pair of second rollers 26 are rotationally driven by the drive mechanism 56. As shown by the arrows in Fig. 7, the pair of second rollers 26 are driven to rotate in the same direction.

[0058] 8, the rod 36a of the drive mechanism 36 again extends to the other side in the longitudinal direction X and pushes the connecting plate 68 of the second slide unit 32 to the other side in the longitudinal direction X. This causes the first roller 24 to come into contact with the piston shoe 2. In this embodiment, the other side in the longitudinal direction X corresponds to the first direction.

[0059] Fig. 9 is a diagram showing the relationship between the piston shoe 2, the first roller 24, and the second roller 26 immediately after the first roller 24 comes into contact with the piston shoe 2. Note that Fig. 9 only partially shows the first roller 24 and the second roller 26.

[0060] As shown in Fig. 9, the first roller 24 has a first pressing surface 24b. The first pressing surface 24b has a circular shape in a cross section parallel to the horizontal direction, and is formed so that the diameter of the cross section increases toward the upper side. Each second roller 26 has a second pressing surface 26b. The second pressing surface 26b has a circular shape in a cross section parallel to the horizontal direction, and is formed so that the diameter of the cross section increases toward the upper side.

[0061] In this embodiment, the first pressing surface 24b is curved in an arc shape in a cross section passing through and parallel to the axis of the rotating shaft 24a (see FIG. 3). Also, in this embodiment, the inclination angle θ of the second pressing surface 26b with respect to the horizontal direction in a cross section passing through and parallel to the axis of the rotating shaft 26a (see FIG. 3) is 45° or less.

[0062] 9, in this embodiment, as the second slide unit 32 (see FIG. 8) moves to the other side in the longitudinal direction X, the first pressing surface 24b of the first roller 24 comes into contact with the corner of the upper end of the holding portion 2b of the piston shoe 2. Note that immediately after the first roller 24 comes into contact with the holding portion 2b, the pair of second rollers 26 are not in contact with the piston shoe 2.

[0063] Next, as shown in FIG. 10, with the first roller 24 in contact with the piston shoe 2, the rod 36a of the drive mechanism 36 extends further in the longitudinal direction X. In this state, the piston shoe 2 prevents the first roller 24 and the second slide unit 32 from moving to the other side in the longitudinal direction X. Therefore, as the rod 36a extends, the cylinder body 36b moves to one side in the longitudinal direction X relative to the first roller 24 and the second slide unit 32. That is, the first slide unit 30 moves to one side in the longitudinal direction X relative to the first roller 24 and the second slide unit 32. As a result, as shown in FIG. 10 and FIG. 11, the pair of second rollers 26 move to one side in the longitudinal direction X and come into contact with the piston shoe 2. In this embodiment, the one side in the longitudinal direction X corresponds to the second direction.

[0064] As shown in FIG. 11, in this embodiment, the first slide unit 30 (see FIG. 10) moves to one side in the longitudinal direction X, so that the second pressing surface 26b of each second roller 26 comes into contact with a corner of the upper end of the holding portion 2b of the piston shoe 2. Note that in this embodiment, each second roller 26 comes into contact with the holding portion 2b in a state in which it is rotationally driven by a drive mechanism 56 (see FIG. 10). As a result, the rotation of each second roller 26 is transmitted to the piston shoe 2, causing the piston shoe 2 to rotate. Furthermore, the rotation of the piston shoe 2 is transmitted to the first roller 24 and the piston 1, causing the first roller 24 and the piston 1 to rotate.

[0065] As described above, in this embodiment, the tip of the rod 38a is not connected to the connecting plate 48. Therefore, as shown in Fig. 10, when the first slide unit 30 moves to one side in the longitudinal direction X as described above, the connecting plate 48 of the first slide unit 30 moves away from the tip of the rod 38a. The rod 62a of the drive mechanism 62 moves backward to one side in the longitudinal direction X as the first slide unit 30 moves.

[0066] 10, in this embodiment, the rod 36a of the drive mechanism 36 extends further in the longitudinal direction X, and the first slide unit 30 moves further to the other side in the longitudinal direction X. As a result, the first roller 24 and the pair of second rollers 26 approach each other further in the longitudinal direction X, and the upper end of the holding portion 2b of the piston shoe 2 is crimped against the connecting portion 1b, as shown in FIG. 12. This connects the piston 1 and the piston shoe 2, and the piston unit 3 is completed.

[0067] Thereafter, the rod 36a of the driving mechanism 36 retreats to one side in the longitudinal direction X, and the rod 62a of the driving mechanism 62 pushes the first slide unit 30 to the other side in the longitudinal direction X, thereby returning the manufacturing apparatus 10 to the state shown in Fig. 3. In this state, the piston unit 3 is removed, and a new piston shoe 2 and piston 1 are installed.

[0068] (Effects of this embodiment) As described above, in the manufacturing apparatus 10 according to the present embodiment, the moving mechanism 28 moves the first roller 24 to the other side in the longitudinal direction X to bring the first pressing surface 24b into contact with the corner of the upper end of the holding portion 2b of the piston shoe 2, and moves the pair of second rollers 26 to one side in the longitudinal direction X to bring the pair of second pressing surfaces 26b into contact with the corner of the upper end of the holding portion 2b. In this case, the first pressing surface 24b and the pair of second pressing surfaces 26b can press the piston shoe 2 not only horizontally but also downward. This allows the piston shoe 2 to be appropriately pressed against the support portion 18, and the piston shoe 2 can be appropriately supported by the support portion 18. As a result, when the upper end of the holding portion 2b is crimped while the piston shoe 2 is rotated, the axial center of the piston 1 and the piston shoe 2 can be prevented from being misaligned, and the piston 1 and the piston shoe 2 can be connected with high accuracy.

[0069] In this embodiment, the first roller 24 is installed as a driven roller, and the pair of second rollers 26 are installed as driving rollers. By using the pair of second rollers 26 as driving rollers in this manner, the piston shoe 2 can be rotated appropriately.

[0070] In addition, in this embodiment, after the first roller 24 is brought into contact with the piston shoe 2, the pair of second rollers 26 are brought into contact with the piston shoe 2. That is, in this embodiment, after the first roller 24 is brought into contact with the piston shoe 2, the piston shoe 2 begins to rotate by the pair of second rollers 26. In this case, more stable processing is possible compared to the case where the first roller 24 is brought into contact with the rotating piston shoe 2.

[0071] In this embodiment, the inclination angle θ (see FIG. 9) of the second pressing surface 26b with respect to the horizontal direction is 45° or less. In this case, the piston shoe 2 can be more reliably pressed against the support portion 18, so that the axial alignment of the piston 1 and the piston shoe 2 can be sufficiently prevented from being misaligned when the upper end of the holding portion 2b is crimped.

[0072] In this embodiment, the first pressing surface 24b has an arc-shaped curved shape. In this case, when the upper end of the holding portion 2b is crimped by the first pressing surface 24b, the upper end of the holding portion 2b can be smoothly curved. This allows the piston 1 and the piston shoe 2 to be connected with higher accuracy.

[0073] In the above embodiment, the pair of second rollers 26 is used as drive rollers, but a drive source for driving the first roller 24 may be provided, and the first roller 24 may be used as a drive roller and the pair of second rollers 26 may be used as driven rollers.

[0074] In the above embodiment, the first pressing surface 24b of the first roller 24 has an arc-shaped curved shape, but the second pressing surface 26b of the second roller 26 may have an arc-shaped curved shape similar to the above-mentioned first pressing surface 24b. In this case, for example, the first pressing surface 24b of the first roller 24 may be a surface whose inclination angle θ with respect to the horizontal direction is 45° or less, similar to the above-mentioned second pressing surface 26b.

[0075] Furthermore, in the above embodiment, the interval between the pair of second rollers 26 in the width direction Y is fixed, but the pair of second rollers 26 may be supported so that the distance between the pair of second rollers 26 in the width direction Y can be adjusted. In this case, the distance between the pair of second rollers 26 in the width direction Y can be adjusted according to the size of the piston shoe to be machined. This makes it possible to appropriately machine piston shoes of various sizes. [Industrial Applicability]

[0076] According to the present invention, it is possible to suppress misalignment of the axes of the piston and the piston shoe when they are connected to each other. [Explanation of symbols]

[0077] 1 piston 2 Piston shoes 3 Piston unit 10 Manufacturing equipment 18 Support part 20 Pressing section 24 First Roller 24b First pressing surface 26 Second Roller 26b Second pressing surface 28 Moving mechanism 56 Drive mechanism

Claims

1. An apparatus for manufacturing a piston unit by connecting a piston having a columnar body and a spherical crown-shaped connecting portion provided at a tip of the body to a piston shoe having a cylindrical holding portion having a spherical crown-shaped inner surface, comprising: a support portion that supports the piston shoe from below so that the holding portion opens upward; a pressing portion that presses the main body portion of the piston downward in a state in which the connecting portion of the piston is fitted into the holding portion of the piston shoe; a first roller having a first pressing surface that presses the holding portion of the piston shoe and is rotatable about a first axis extending in a vertical direction; a pair of second rollers each having a second pressing surface that presses against the holding portion of the piston shoe and being rotatable about a second axis extending in the vertical direction; a drive source that rotates the first roller or the pair of second rollers; a moving mechanism for moving the first roller and the pair of second rollers in a horizontal direction, the first pressing surface and the second pressing surface have a circular shape in a cross section parallel to a horizontal direction, and are formed so that a diameter of the cross section increases toward an upper side, The moving mechanism moves the first roller in a first direction parallel to the horizontal direction to bring the first pressing surface into contact with a corner of the upper end of the holding portion, and moves the pair of second rollers in a second direction opposite to the first direction to bring the second pressing surface into contact with the corner of the upper end of the holding portion.

2. The manufacturing apparatus for a piston unit according to claim 1 , wherein the driving source rotates the pair of second rollers.

3. The piston unit manufacturing apparatus according to claim 2 , wherein the moving mechanism brings the pair of second rollers into contact with the holding portion after bringing the first roller into contact with the holding portion.

4. 4. The manufacturing apparatus for a piston unit according to claim 2 or 3, wherein an inclination angle of the second pressing surface with respect to a horizontal direction in a cross section passing through the second axis and parallel to the second axis is 45° or less.

5. The piston unit manufacturing apparatus according to claim 4 , wherein the first pressing surface is curved in an arc shape in a cross section passing through the first axis and parallel to the first axis.

6. A method for manufacturing a piston unit by connecting a piston having a columnar body and a spherical crown-shaped connecting portion provided at a tip of the body to a piston shoe having a cylindrical holding portion having a spherical crown-shaped inner surface, comprising: The piston shoe is supported from below so that the holding portion opens upward, pressing the body portion of the piston downward with the connecting portion of the piston fitted in the holding portion of the piston shoe; Rotating a first roller that rotates about a first axis extending in the vertical direction or a pair of second rollers that rotate about a second axis extending in the vertical direction; Moving the first roller and the pair of second rollers in a horizontal direction; pressing the holding portion of the piston shoe with a first pressing surface of the first roller and a second pressing surface of the pair of second rollers; the first pressing surface and the second pressing surface have a circular shape in a cross section parallel to a horizontal direction, and are formed so that a diameter of the cross section increases toward an upper side, A manufacturing method for a piston unit, wherein, when moving the first roller and the pair of second rollers horizontally, the first roller is moved in a first direction parallel to the horizontal direction to bring the first pressing surface into contact with a corner of an upper end portion of the holding portion, and the pair of second rollers are moved in a second direction opposite to the first direction to bring the second pressing surface into contact with a corner of an upper end portion of the holding portion.

7. The method for manufacturing a piston unit according to claim 6 , further comprising the step of rotating the pair of second rollers.

8. The manufacturing method of a piston unit according to claim 7, wherein when the first roller and the pair of second rollers are moved in a horizontal direction, the first roller is brought into contact with the holding portion, and then the pair of second rollers are brought into contact with the holding portion.

9. 9. The method for manufacturing a piston unit according to claim 7 or 8, wherein an inclination angle of the second pressing surface with respect to a horizontal direction in a cross section passing through the second axis and parallel to the second axis is 45° or less.

10. The method for manufacturing a piston unit according to claim 9 , wherein the first pressing surface is curved in an arc shape in a cross section passing through the first axis and parallel to the first axis.

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