Element manufacturing apparatus and element manufacturing method

Abstract

To provide a manufacturing device of element which secures a necessary plate thickness by reducing sagging occurring between a saddle surface and body front according to a punching work while shortening a distance between the saddle surface and a rocking edge formed on the body front, in the manufacturing device which forms element according to the punching work.SOLUTION: A manufacturing device of element manufactures an element which has a slot part, a saddle surface with which an inner circumferential surface of a ring to be inserted to the slot part is brought into contact and a rocking edge from plate-shaped raw material according to press working. The device includes a die, a punch and a plate holder, at least one side of the die and the plate holder has a protrusion part which is protruded in such a direction as to be proximate to each other in a slot formation part in which the slot part is formed. Therein, upon drawing forming of the slot part, the plate holding is pressurized and moved by pressurizing of raw material by means of the die, thereby, drawing molding is initiated and upsetting molding is caused by the protrusion part before initiation of the drawing molding.SELECTED DRAWING: Figure 21

Description

[Technical field]

[0001] The present specification discloses an element manufacturing apparatus. [Background technology]

[0002] Conventionally, in the manufacture of elements that constitute a transmission belt of a continuously variable transmission by being connected with a ring, a method is known in which a plate material is sandwiched between a punch and an ejector facing the punch, and the element is punched out along the die shape by the punch. For example, Patent Document 1 discloses a method for manufacturing an element that constitutes a transmission belt, which has a head portion, a body portion (trunk portion) including a pitch portion at an upper portion, and a neck portion connecting the head portion and the body portion, and a hoop (ring) is attached between the ear portion and the pitch portion, in which an arc-shaped protuberance is provided on the forming surface of the ejector facing the punch and the element is punched out, thereby forming a curved portion between the saddle surface, which is the upper surface of the pitch portion, and the front surface of the body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-43719 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a transmission belt in which a plurality of elements are connected by rings, in order to increase the torque transmission efficiency, it is desirable that the rocking edge, which is formed on the front surface of the body of the element and serves as a fulcrum when adjacent elements rotate relative to each other, is formed in a position close to the saddle surface. On the other hand, the thickness of the body of the element is greatest between the saddle surface and the rocking edge, but in order to make the gap between the adjacent elements appropriate, a specified thickness must be ensured between the saddle surface and the rocking edge. When an element is manufactured by punching, a curved surface (convex curved surface) is usually formed between the saddle surface and the front surface of the body due to sagging caused by the punching process. If the sagging becomes large, the thickness between the saddle surface of the body and the rocking edge decreases accordingly, making it difficult to shorten the distance between the saddle surface and the rocking edge while ensuring the specified thickness of the body, which may reduce the torque transmission efficiency.

[0005] The element manufacturing apparatus disclosed herein forms elements by punching, and its main objective is to provide an element manufacturing apparatus that can reduce the sagging that occurs between the saddle surface and the front surface of the body due to the punching process, and shorten the distance between the saddle surface and the rocking edge formed on the front surface of the body while ensuring the required plate thickness for the body. [Means for solving the problem]

[0006] The element manufacturing apparatus of the present disclosure employs the following means to achieve the above-mentioned main object.

[0007] The manufacturing apparatus for the first element of the present disclosure comprises: The present invention provides an element manufacturing device for manufacturing an element, which is arranged in an annular shape by an endless ring to constitute a transmission belt that is wound around a pair of pulleys of a continuously variable transmission, by pressing a plate-shaped material to manufacture the element, which has a slot portion, a saddle surface that contacts an inner peripheral surface of the ring inserted into the slot portion, and a rocking edge that serves as a fulcrum when adjacent elements contact each other and rotate relative to each other, the device comprising: The press working mold includes a die having an inner hole, a punch that is inserted into the inner hole of the die to punch out the material into the outer shape of the element, and a plate holder that is arranged opposite the die to sandwich and hold down the material, At least one of the die and the plate holder has a protrusion protruding in a direction approaching each other in a slot forming portion that forms the slot portion, When punching the slot portion, the blank is pressed by the die to move the plate holder, and the blank is started. Before the blank is started, the protrusion generates an upsetting. The gist of the present invention is as follows.

[0008] In the first element manufacturing device, at least one of the die and the plate holder has a convex portion that protrudes toward each other in a slot forming portion that forms the slot portion. When punching the slot portion, the plate holder is pressed and moved by the die to start punching, and the convex portion causes upsetting before the start of punching. This allows the material to flow between the saddle surface and the front of the body by upsetting before punching, and reduces sagging between the saddle surface and the front of the body. As a result, in an element manufacturing device that forms an element by punching, it is possible to reduce sagging that occurs between the saddle surface and the front of the body by punching, and shorten the distance between the saddle surface and the rocking edge formed on the front of the body while ensuring the plate thickness required for the body.

[0009] The manufacturing apparatus for the second element of the present disclosure includes: The present invention provides an element manufacturing device for manufacturing an element, which is arranged in an annular shape by an endless ring to constitute a transmission belt that is wound around a pair of pulleys of a continuously variable transmission, by pressing a plate-shaped material to manufacture the element, which has a slot portion, a saddle surface that contacts an inner peripheral surface of the ring inserted into the slot portion, and a rocking edge that serves as a fulcrum when adjacent elements contact each other and rotate relative to each other, the device comprising: The press working mold includes a die having an inner hole, a punch that is inserted into the inner hole of the die to punch out the material into the outer shape of the element, and a plate holder that is arranged opposite the die to sandwich and hold down the material, At least one of the die and the plate holder has a protrusion protruding in a direction approaching each other in a slot forming portion that forms the slot portion, During punching of the slot portion, the slot forming portion of the plate holder is moved away from the contact surface of the punch with the material, and the material of the material is pressed by the slot forming portion of the die, so that the material of the material flows into a recess defined by the slot forming portion of the plate holder and the surrounding side surface of the punch, and then the plate holder is pressed and moved by the pressurization of the material by the die after the upsetting, thereby starting the punching. The gist of the present invention is as follows.

[0010] In this second element manufacturing device, at least one of the die and the plate holder has a convex portion protruding in a direction approaching each other in a slot forming portion that forms the slot portion. Then, when punching the slot portion, the slot forming portion of the plate holder is retracted from the contact surface of the punch with the material, and the material is pressed by the slot forming portion of the die, so that the material flows into a recess defined by the slot forming portion of the plate holder and the side surface of the punch around it, and then the plate holder is upset by the convex portion, and after upset, the plate holder is moved by pressure applied to the material by the die, so that punching begins. This allows the material to flow between the saddle surface and the front of the body by upset forming before punching, and sagging between the saddle surface and the front of the body can be reduced. As a result, in a device that forms an element by punching, it is possible to reduce sagging between the saddle surface and the front of the body by punching, and to shorten the distance between the saddle surface and the rocking edge formed on the front of the body while ensuring the plate thickness required for the body. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic diagram of a continuously variable transmission having a transmission belt; [Diagram 2] FIG. 2 is a schematic diagram of a transmission belt. [Diagram 3] FIG. 2 is a schematic configuration diagram of an element manufacturing apparatus including a press machine. [Figure 4] 3 is a cross-sectional view of a press at the AA cross-section molding portion of the element in FIG. 2. [Diagram 5] 3 is a cross-sectional view of a press at a BB cross-section molding portion of the element in FIG. 2. [Figure 6] FIG. [Figure 7] 7 is a cross-sectional view taken along the line XX in FIG. 6 and a side view taken along the line Y. [Figure 8] FIG. 2 is an explanatory view showing the molding of the AA cross section of the element. [Figure 9]FIG. 2 is an explanatory view showing the molding of the AA cross section of the element. [Figure 10] FIG. 2 is an explanatory view showing the molding of the AA cross section of the element. [Figure 11] FIG. 2 is an explanatory view showing the molding of the AA cross section of the element. [Figure 12] FIG. 2 is an explanatory view showing the molding of the AA cross section of the element. [Figure 13] FIG. 2 is an explanatory view showing the molding of the AA cross section of the element. [Figure 14] FIG. 13 is an explanatory diagram showing the molding of the BB cross section of the element. [Figure 15] FIG. 13 is an explanatory diagram showing the molding of the BB cross section of the element. [Figure 16] FIG. 13 is an explanatory diagram showing the molding of the BB cross section of the element. [Figure 17] FIG. 13 is an explanatory diagram showing the molding of the BB cross section of the element. [Figure 18] FIG. 13 is an explanatory diagram showing the molding of the BB cross section of the element. [Figure 19] FIG. 13 is an explanatory diagram showing the molding of the BB cross section of the element. [Figure 20] 13 is an explanatory diagram showing a state in which a slot portion is formed in a comparative example. FIG. [Figure 21] 5A to 5C are explanatory diagrams showing how slots are formed in the present embodiment. [Figure 22] 10 is an explanatory diagram comparing the size of sagging that occurs during punching of the slot portion in this embodiment and in a comparative example. FIG. [Figure 23] 13 is an explanatory diagram showing a state in which a slot portion is formed in another embodiment. FIG. [Figure 24] FIG. 11 is a schematic diagram of a transmission belt according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Next, an embodiment of the present disclosure will be described with reference to the drawings.

[0013] Fig. 1 is a schematic diagram of a continuously variable transmission having a power transmission belt, and Fig. 2 is a schematic diagram of the power transmission belt. As shown in Fig. 1, the continuously variable transmission 1 has a primary shaft 2 as a driving side rotating shaft, a primary pulley 3 provided on the primary shaft 2, a secondary shaft 4 as a driven side rotating shaft arranged in parallel to the primary shaft 2, and a secondary pulley 5 provided on the secondary shaft 4. A power transmission belt 10 is wound around the pulley groove (V-shaped groove) of the primary pulley 3 and the pulley groove (V-shaped groove) of the secondary pulley 5.

[0014] The primary shaft 2 is connected to an input shaft (not shown) that is connected to a power generation source such as an engine (internal combustion engine) via a forward / reverse switching mechanism (not shown). The primary pulley 3 has a fixed sheave 3a formed integrally with the primary shaft 2, and a movable sheave 3b supported by the primary shaft 2 via a ball spline or the like so as to be slidable in the axial direction. The secondary pulley 5 has a fixed sheave 5a formed integrally with the secondary shaft 4, and a movable sheave 5b supported by the secondary shaft 4 via a ball spline or the like so as to be slidable in the axial direction and biased in the axial direction by a return spring 8.

[0015] Furthermore, the continuously variable transmission 1 has a primary cylinder 6 which is a hydraulic actuator for changing the groove width of the primary pulley 3, and a secondary cylinder 7 which is a hydraulic actuator for changing the groove width of the secondary pulley 5. The primary cylinder 6 is formed behind the movable sheave 3b of the primary pulley 3, and the secondary cylinder 7 is formed behind the movable sheave 5b of the secondary pulley 5. Hydraulic oil is supplied to the primary cylinder 6 and the secondary cylinder 7 from a hydraulic control device (not shown) in order to change the groove width between the primary pulley 3 and the secondary pulley 5, so that the torque transmitted from the engine or the like to the primary shaft 2 via the input shaft and the forward / reverse switching mechanism can be output to the secondary shaft 4 with a stepless speed change. The torque output to the secondary shaft 4 is transmitted to the drive wheels of the vehicle (all not shown) via a gear mechanism, a differential gear, and a drive shaft.

[0016] As shown in Fig. 2, the power transmission belt 10 has two laminated rings 12 formed by laminating a plurality of elastically deformable ring materials 11 (for example, nine in this embodiment) in the thickness direction (ring radial direction), and a plurality of elements 20 (for example, several hundred elements) arranged (bundled) in an annular shape along the inner peripheral surface of the laminated rings 12. The plurality of ring materials 11 constituting the laminated rings 12 are elastically deformable materials cut out from a drum made of a steel plate, and are processed to have approximately the same thickness and different circumferential lengths that are determined in advance. In addition, each ring material 11 is gently curved so that the central portion in the axial direction slightly protrudes radially outward.

[0017] Each element 20 is punched out by pressing from a metal strip-shaped material (strip material 110). In this embodiment, one surface of the strip material 110 is formed as a stepped surface having one step in the width direction (short side direction), and the other surface is formed as a flat surface. One surface of the strip material 110 becomes the front surface of the element 20, and the other surface of the strip material 110 becomes the back surface of the element 20.

[0018] As shown in Fig. 2, each element 20 has a body portion 21 extending horizontally in the figure, a neck portion 22 extending from the center in the width direction of the body portion 21 to the outer periphery of the power transmission belt 10 (outside in the radial direction of the power transmission belt 10 and the laminated ring 12), and a head portion 23 including a pair of ear portions 23a extending from the neck portion 22 to both sides in the width direction of the body portion 21 so as to be spaced apart from the body portion 21. The width of the body portion 21 is equal to or greater than the width of the head portion 23, and the body portion 21, the neck portion 22, and the ear portions 23a of the head portion 23 define two concave slot portions 24 that are ring accommodating portions. In addition, one protrusion (dimple) 23p is formed in the center in the width direction of the front surface (one surface) of the head portion 23, and a recess 23r is formed in the back surface (other surface) of the head portion 23 so as to be located behind the protrusion 23p.

[0019] The lamination ring 12 is fitted into the slot portion 24 of each element 20 so as to sandwich the element 20 from both sides, and the protrusion 23p of each element 20 is loosely fitted into the recess 23r of the adjacent element 20. In this way, a large number of elements 20 are bound by the two lamination rings 12 in a circular arrangement. In addition, the surface of the body portion 21 (the upper surface in FIG. 2) that defines the slot portion 24 becomes a saddle surface 21a that contacts the inner peripheral surface of the lamination ring 12 (the ring material 11 of the innermost layer). In other words, the saddle surface 21a is located on both sides in the width direction of the neck portion 22.

[0020] Each saddle surface 21a is a convex curved surface curved toward the laminated ring 12. That is, each saddle surface 21a has a symmetrical convex curved shape (crowning shape) that has an apex near the center in the width direction and gradually slopes downward in the figure from the apex toward the outside in the width direction and toward the neck portion 22 side. This allows the laminated ring 12 to be centered by applying a centripetal force toward the apex T due to friction with the saddle surface 21a. However, the saddle surface 21a may include a plurality of convex curved surfaces that curve outward in the radial direction of the transmission belt 10, etc. In addition, the radius of curvature of the saddle surface 21a (convex curved surface) is set to be smaller than the radius of curvature of the innermost ring material 11 (laminated ring 12) along the axial direction.

[0021] Further, the body 21 of each element 20 has a pair of side surfaces 21f formed to be spaced apart from each other from the inner peripheral side to the outer peripheral side (the outer side in the radial direction of the power transmission belt, etc.) of the power transmission belt 10. Each side surface 21f is in frictional contact with the surface of the pulley groove of the primary pulley 3 or the pulley groove of the secondary pulley 5, receives the clamping pressure from the pulleys 3, 5, and serves as a torque transmission surface (flank surface) that transmits torque from the primary pulley 3 to the secondary pulley 5 by the frictional force. In this embodiment, as shown in the figure, the surface of each side surface 21f is formed with unevenness (multiple grooves) for holding hydraulic oil for lubricating and cooling the contact portion between each element 20 and the primary pulley 3 or the secondary pulley 5.

[0022] Furthermore, as shown in FIG. 2, the front surface (surface on the protrusion 23p side) of the element 20 of this embodiment includes the inclined surface 21s, and the back surface is formed flat. That is, a part of the outer circumferential side (outside in the radial direction of the transmission belt 10, etc.) of the body 21, the neck portion 22, and the head portion 23 have a substantially constant thickness, and the body 21 is formed with the inclined surface 21s that approaches the back surface as it moves further inward from a position on the inner circumferential side (inside in the radial direction of the transmission belt 10, etc.) of the saddle surface 21a. Also, the inner circumferential portion (lower end portion in FIG. 2) of the body 21 is formed with a step portion 21b that is thinner than the portion including the inclined surface 21s of the body 21 and has a substantially constant thickness. The boundary portion between the flat portion including the neck portion 22, the head portion 23, etc. and the inclined surface 21s forms a rocking edge 25 that brings the elements 20 adjacent to each other in the traveling direction of the transmission belt 10 into contact with each other and serves as a fulcrum for the rotation of both of them. That is, in each element 20, the rocking edge 25 is located on the inner peripheral side of each saddle surface 21a.

[0023] Next, the manufacture of the element 20 thus constructed will be described. Fig. 3 is a schematic diagram of an element manufacturing apparatus including a press machine, Fig. 4 is a cross-sectional view of the press machine at the AA cross-section forming portion of the element in Fig. 2, and Fig. 5 is a cross-sectional view of the press machine at the BB cross-section forming portion of the element in Fig. 2. As shown in Fig. 3, the element manufacturing apparatus 100 has an uncoiler 101 that unwinds the coil material C around which the strip-shaped material 110 is wound, a feeder 102 that feeds the strip-shaped material 110 unwound by the uncoiler 101 in the longitudinal direction, and a press machine 120 that punches out the strip-shaped material 110 fed by the feeder 102 to form the element 20.

[0024] In this embodiment, the press machine 120 is configured as a fine blanking press machine, and performs press working on the strip-shaped material 110 by sequentially forming the plate thickness (plate thickness forming), forming the protrusions 23p and the recesses 23r (dimple / hole forming), and punching out the elements 20 (punching forming) in one stroke. This press machine 120 includes a fixed upper die 130 and a movable lower die 140 that are arranged to face each other.

[0025] As shown in FIG. 4, the upper die 130 includes an upper plate 131 as a fixed plate fixed to the frame of the press machine 120, a punch 132 having a cutting edge with an outer shape corresponding to the contour of the element 20 and movable vertically relative to the upper plate 131 below the upper plate 131, a plate holder 133 arranged to surround the periphery of the punch 132 and movable vertically relative to the upper plate 131 below the upper plate 131, and an embossing pin 134. The pressure of the punch 132 is adjusted by, for example, a hydraulic control device so that a predetermined load is generated during press processing. The pressure of the plate holder 133 is adjusted by, for example, a hydraulic control device so that a predetermined load is generated independently of the punch 132 during press processing. The embossing pin 134 is fixed at its base end to the upper plate 131 and is arranged to penetrate the punch 132 vertically with its tip (pressure portion) facing downward. As described above, the punch 132 is movable relative to the upper plate 131 , and therefore the embossing pin 134 is movable relative to the punch 132 .

[0026] As shown in FIG. 4, the lower mold 140 includes a lower plate 141 as a movable plate that moves toward and away from the upper plate 131, a die 142 that has an inner hole 142o (cutting edge) of a shape corresponding to the cutting edge of the punch 132 at a position facing the punch 132 and is fixed to the lower plate 141 so that their end faces face each other relative to the plate holder 133, an ejector 143 arranged in the inner hole 142o (at a position facing the punch 132) of the die 142, and an ejection pin 144.

[0027] The pressure applied by the ejector 143 is adjusted, for example, by a hydraulic control device so that a predetermined load is generated independently of the punch 132 and the plate holder 133 during press working. As shown in Fig. 4, a protrusion forming hole 143h extending vertically is formed at a position facing the embossing pin 134 of the ejector 143 for forming the protrusion 23p and the recess 23r of the element 20. The ejection pin 144 is disposed in the protrusion forming hole 143h and protrudes from and retracts into the end face (upper face) of the ejector 143 facing the punch 132, and ejects the press-molded product (element 20) after press working.

[0028] 6 and 7(a), the slot forming portion 142s of the cutting edge of the die 142 that forms the slot portion 24 of the element 20 has a tapered chamfered portion 142t formed at the corners of both the head portion 23 side and the body portion 21 (saddle surface 21a) side of the slot portion 24. The chamfered portion 142t on the body portion 21 side is formed so that the gap (clearance c) between the side of the surrounding punch 132 and the taper depth d are smaller than those of the chamfered portion 142t on the head portion 23 side. Specifically, the chamfered portion 142t on the body portion 21 side is formed so that the clearance c is 4% or more and 40% or less (for example, 0.05 mm or more and 0.5 mm or less) of the thickness of the strip-shaped material 110 in order to reduce wear and damage to the cutting edge of the die 142. Furthermore, the chamfered portion 142t on the side of the body 21 is formed so that the taper depth d is 4% or more and 40% or less (for example, 0.05 mm or more and 0.5 mm or less) of the plate thickness of the strip-shaped material 110 so as to prevent the sagging that occurs between the saddle surface 21a and the front of the body 21 from expanding during press processing (punching processing).

[0029] 6 and 7(b), the slot forming portion 142s of the die 142 is formed by a convex portion protruding toward the slot forming portion 133s of the opposing plate holder 133. A gently sloping gradually changing portion G is formed around the slot forming portion 142s (convex portion) of the die 142 (the hatched area in FIG. 6). Furthermore, in this embodiment, the slot forming portion 133s of the plate holder 133 opposing the slot forming portion 142s of the die 142 is also similarly formed by a convex portion protruding toward the slot forming portion 142s of the die 142. Similarly, a gently sloping gradually changing portion is formed around the slot forming portion 133s (convex portion) of the plate holder 133. As a result, when the strip material 110 is sandwiched between the die 142 and the plate holder 133 to perform punching, the slot forming portions 132s and 133s can be brought into contact with the strip material 110 first, and upset forming (crushing) can be performed on the portion of the strip material 110 where the slot portion 24 is to be formed prior to the punching. Details of upset forming will be described later.

[0030] Next, the operation of the element manufacturing apparatus 100 thus configured will be described. Figures 8 to 13 are explanatory views showing the state of molding the AA cross section of the element in Figure 2, and Figures 14 to 19 are explanatory views showing the state of molding the BB cross section of the element in Figure 2. The manufacture of the element 20, in particular the molding of the slot portion 24, will be described below with reference to Figures 8 to 19.

[0031] In manufacturing the element 20, the press 120 first drives the feed device 102 to feed the strip material 110 between the upper die 130 and the lower die 140 so that one surface (step surface) of the strip material 110 faces the lower die 140 and the other surface (flat surface) faces the upper die 130b, and then lifts the lower plate 141 and brings the ejector 143 into contact with one surface of the strip material 110 (see Figs. 8 and 14). If an abnormal load is detected in the ejector 143 while the lower plate 141 is rising, it is determined that the previously pressed molded product has not been ejected normally and remains, and the press process is stopped.

[0032] When the lower plate 141 is further raised, a pressure is applied from the ejector 143 to the strip-shaped material 110, and the strip-shaped material 110 is sandwiched between the ejector 143 and the punch 132 to perform thickness shaping to adjust the thickness (see Figs. 9 and 15). When the strip-shaped material 110 is pressed by the ejector 143, the punch 132 is pressed and moved (raised) in a direction approaching the upper plate 131 by the pressure of the ejector 143 (see Figs. 10 and 16), and eventually hits the upper plate 131 and stops (see Figs. 11 and 17).

[0033] When the punch 132 hits the upper plate 131, the embossing pin 134 protrudes downward from the contact surface of the punch 132 with the strip-shaped material 110 and applies pressure to the other surface (flat surface) of the strip-shaped material 110 (see Figs. 10 and 11). As a result, a depression 23r is formed in the other surface of the strip-shaped material 110, and material flows from one surface of the strip-shaped material 110 into the protrusion forming hole 143h to form a protrusion 23p (dimple / hole forming).

[0034] When the lower plate 141 is further raised, the die 142 comes into contact with one surface of the strip-shaped material 110 (see Figs. 11 and 17), and while the die 142 and the plate holder 133 press the strip-shaped material 110, the punch 132 and the ejector 143 hold and shear the strip-shaped material 110, thereby moving to punching out the outer shape of the element 20 (see Figs. 12, 13, 18 and 19). The press-molded product produced by punching out is ejected from the press 120 by the ejection pin 144 protruding above the contact surface of the ejector 143 with the press-molded product and being blown off by air blow or the like. Then, the press-molded product is subjected to necessary post-processing (hardening, polishing, etc.) to complete the element 20.

[0035] FIG. 20 is an explanatory diagram showing the state of the formation of the slot portion in the comparative example, and FIG. 21 is an explanatory diagram showing the state of the formation of the slot portion in the present embodiment. In the comparative example, as shown in FIG. 20, the slot forming portion 142s of the die 142 and the slot forming portion 133s of the plate holder 133 are not formed by convex portions protruding in the direction facing each other, but are formed by flat portions. The slot forming portion 142s of the die 142 and the slot forming portion 133s of the plate holder 133 come into contact with the strip-shaped material 110 at substantially the same time as their surroundings, and punching is started without causing upsetting. In this case, as shown by the dashed line in FIG. 20, in the portion between the saddle surface 21a and the front surface of the body portion 21, sagging expands as punching progresses, and the plate thickness tb of the body portion 21 is reduced by the expansion of the sagging. Here, in the power transmission belt 10, it is desirable that the rocking edge 25 is formed as close as possible to the saddle surface 21a in order to improve the torque transmission efficiency. On the other hand, the thickness of the body 21 of the element 20 is greatest between the saddle surface 21a and the rocking edge 25, but in order to ensure an appropriate gap between adjacent elements 20 in the power transmission belt 10, a specified thickness must be ensured between the saddle surface 21a of the body 21 and the rocking edge 25. For this reason, if excessive sagging occurs between the saddle surface 21a and the front surface of the body 21 due to punching, as described above, the thickness tb of the body 21 will be reduced, making it difficult to shorten the distance between the saddle surface 21a and the rocking edge 25 while ensuring the specified thickness of the body 21.

[0036] In contrast, in this embodiment, as shown in FIG. 21, the slot forming portion 142s of the die 142 and the slot forming portion 133s of the plate holder 133 are formed by convex portions protruding in the direction facing each other, and come into contact with the strip-shaped material 110 before other portions, and sandwich the strip-shaped material 110 from above and below, thereby causing upset forming (crushing forming). As a result, as shown by the dashed line in FIG. 21, material flows between the saddle surface 21a and the front surface of the body 21 by upset forming, so that the expansion of sagging can be reduced. In this embodiment, during upset forming, one or both of the pressure force of the die 142 and the back pressure of the plate holder 133 are adjusted so that the rise (movement) of the slot forming portion 142s of the die 142 is greater than the rise (movement) of the slot forming portion 133s of the plate holder 133. This makes it possible to more reliably cause upset forming and allow sufficient material to flow between the saddle surface 21a and the front surface of the body 21. As the lower plate 141 rises, the pressure applied to the strip-shaped material 110 by the die 142 increases. When this overcomes the reverse back pressure from the sheet clamp 133 to the strip-shaped material 110, the sheet clamp 133 is moved (raised) under pressure by the pressure from the die 142. As the sheet clamp 133 rises, upsetting is completed and punching begins.

[0037] Furthermore, in this embodiment, the slot forming portion 142s of the die 142 is provided with tapered chamfered portions 142t at the corners of both the head portion 23 side and the body portion 21 side of the slot portion 24, and the clearance c and taper depth d of the chamfered portion 142t on the body portion 21 side are made smaller than those of the chamfered portion 142t on the head portion 23 side. This allows shearing of the strip-shaped material 110 on the saddle surface 21a side at an early timing after punching of the slot portion 24 is started, and the expansion of sagging on the saddle surface 21a side can be further reduced. Therefore, as shown in FIG. 22, in this embodiment, it is possible to reduce sagging generated between the saddle surface 21a and the front surface of the body portion 21 during punching of the slot portion 24 compared to the comparative example. As a result, it is possible to bring the rocking edge 25 closer to the saddle surface 21a while maintaining the specified plate thickness of the body 21 between the saddle surface 21a and the rocking edge 25, thereby improving the torque transmission efficiency.

[0038] It goes without saying that the invention of the present disclosure is in no way limited to the above-described embodiment, and can be embodied in various forms as long as it falls within the technical scope of the present disclosure.

[0039] For example, in the embodiment described above, the slot forming portion 142s of the die 142 and the slot forming portion 133s of the plate holder 133 are formed by convex portions so as to protrude in directions approaching each other. However, of the slot forming portion 142s of the die 142 and the slot forming portion 133s of the plate holder 133, only the former slot forming portion 142s may be formed by a convex portion, or only the latter slot forming portion 133s may be formed by a convex portion.

[0040] In the above-described embodiment, in order to reduce the expansion of sagging between the saddle surface 21a and the front surface of the body portion 21, when forming the slot portion 24, upset forming (crushing forming) is performed before the start of punch forming associated with the elevation of the sheet holder 133. However, it is also possible to pressurize the strip material 110 with the slot forming portion 142s of the die 142 from a state in which the slot forming portion 133s of the sheet holder 133 is retracted from the contact surface of the punch 132 with the strip material 110, thereby causing the material of the strip material 110 to flow into a recess defined by the slot forming portion 133s of the sheet holder 133 and the side surface of the punch 132 around it before upset forming. FIG. 23 is an explanatory diagram showing the formation of a slot portion in another embodiment. As shown in the figure, the die conditions are set so that the sheet holder 133 (slot forming portion 133s) is separated from the sheet material 110 while the punch 132 is in contact with the other surface of the sheet material 110, and the die 142 is raised to press the sheet material 110 with the slot forming portion 142s of the die 142. As a result, the material of the sheet material 110 flows into a recess defined by the slot forming portion 133s of the sheet holder 133 and the side surface of the punch 132 due to the pressing force from the slot forming portion 142s of the die 142. When the flowed-in material reaches the slot forming portion 133s and the die 142 is further raised, upsetting occurs due to the pressing force from the slot forming portion 142s of the die 142 and the reverse back pressure from the slot forming portion 133s of the sheet holder 133, and the upsetting causes the material of the sheet material 110 to flow between the saddle surface 21a and the front surface of the body portion 21, thereby reducing the expansion of sagging. As a result, as in the present embodiment, by reducing the expansion of sagging between the saddle surface 21a and the front of the body 21, it is possible to ensure the plate thickness of the body 21 between the saddle surface 21a and the rocking edge 25 while bringing the rocking edge 25 closer to the saddle surface 21a, thereby improving the torque transmission efficiency.

[0041] In the above-mentioned embodiment, the manufacturing apparatus 100 for an element according to the present disclosure has been described as being applied to the manufacture of an element 20 having two slots 24 in which a body 21 and a head 23 are connected via a neck 22 and a laminated ring 12 is fitted between an ear 23a of the head 23 and the body 21. However, the manufacturing apparatus 100 may be applied to the manufacture of any other type of element having a slot in which a ring is accommodated. FIG. 24 is a schematic diagram showing a transmission belt including an element according to another embodiment. The transmission belt 210 has one laminated ring 12 formed by laminating a plurality of elastically deformable ring members 11 (for example, nine in this embodiment) in the thickness direction (ring radial direction), one retainer ring 15, and a plurality of elements 220 (for example, several hundreds) arranged (bundled) in a ring shape along the inner circumferential surface of the laminated ring 12.

[0042] The retainer ring 15 is elastically deformable and cut out from, for example, a drum made of steel plate, and has a thickness that is approximately the same as or thinner than that of the ring material 11. The retainer ring 15 also has an inner peripheral length that is longer than the outer peripheral length of the ring material 11 of the outermost layer of the laminated ring 12. As a result, when the laminated ring 12 and the retainer ring 15 are concentrically arranged (unloaded state in which no tension is applied), an annular clearance is formed between the outer peripheral surface of the ring material 11 of the outermost layer and the inner peripheral surface of the retainer ring 15, as shown in FIG.

[0043] Each element 220 is punched out by pressing from a metal strip-shaped material (strip-shaped material 110), and as shown in Fig. 24, has a body portion 221 extending horizontally in the figure, a pair of pillar portions 222 extending in the same direction from both ends of the body portion 221, and a slot portion (recess) 224 as a single ring accommodating portion defined between the pair of pillar portions 222 so as to open to the free end side of each pillar portion 222. The pair of pillar portions 222 extend outward in the radial direction of the power transmission belt 210 (in the direction from the inner periphery side toward the outer periphery side of the power transmission belt 210, i.e., upward in the figure) from both sides in the width direction of a saddle surface 224a which is the bottom surface of the slot portion 224, and a hook portion 222f protruding in the width direction of the saddle surface 224a is formed at the free end of each pillar portion 222. The pair of hook portions 222f face each other at a distance that is slightly longer than the width of the laminated ring 12 (ring material 11) and shorter than the width of the retaining ring 15.

[0044] As shown in FIG. 24, the laminated ring 12 is placed in the slot portion 224, and the saddle surface 224a of the slot portion 224 contacts the inner peripheral surface of the laminated ring 12 (the innermost ring material 11). The saddle surface 224a has a symmetrical convex curved shape (crowning shape) that is gently inclined downward in the drawing from the central part in the width direction as it goes outward in the width direction. This makes it possible to center the laminated ring 12 by applying a centripetal force toward the top to the laminated ring 12 due to friction with the saddle surface 224a. However, the saddle surface 224a may include multiple convex curved surfaces that curve outward in the radial direction of the laminated ring 12.

[0045] Furthermore, with the laminated ring 12 disposed in the slot portions 224 of all the elements 220, the retainer ring 15 is elastically deformed and fitted into the slot portions 224 via a pair of hook portions 222f of each element 220. The retainer ring 15 is disposed between the outer peripheral surface of the ring material 11 of the outermost layer of the laminated ring 12 and the hook portions 222f of each element 220 to surround the laminated ring 12 and prevent each element 220 from falling off the laminated ring 12. As a result, the multiple elements 220 are bound (arranged) in an annular shape along the inner peripheral surface of the laminated ring 12.

[0046] The front surface of the element 220 includes a slope 221s, and the back surface is formed flat. That is, a part of the outer circumferential side (the outer side in the radial direction of the drive belt 210, etc.) of the body 221 and the pillar portion 222 have a substantially constant thickness, and the body 221 has a slope 221s that approaches the back surface from a position on the inner circumferential side (the inner side in the radial direction of the drive belt 210, etc.) of the saddle surface 224a toward the inner circumferential side. The edge portion on the outer circumferential side of the slope 221s (the boundary portion where the thickness of the element 220 changes) brings the adjacent elements 220 into contact with each other in the traveling direction of the drive belt 10 to form a rocking edge 225 that serves as a fulcrum for the rotation of the elements 220. As a result, the rocking edge 225 is located on the inner circumferential side of the saddle surface 224a. Moreover, one protrusion (dimple) 221p is formed in the center in the width direction of the front surface (one surface) of the body 221, and a recess 211r is formed on the back surface (the other surface) of the body 221 so as to be located on the back side of the protrusion 221p. Furthermore, the body 221 of the element 220 has a pair of side surfaces 221f that are formed so as to be spaced apart from each other from the inner periphery side of the power transmission belt 210 etc. toward the outer periphery side (the outer side in the radial direction of the power transmission belt 210 etc.) and function as flank surfaces.

[0047] The element 220 thus configured can be manufactured by punching the strip-shaped material 110 using a press, similarly to the element 20 of this embodiment. When punching the slot portion 224, before the start of the punching, the slot forming portion (convex portion) of the die or the slot forming portion (convex portion) of the plate holder causes upsetting (crushing) of the strip-shaped material, thereby preventing the sagging between the saddle surface 224a and the front surface of the body portion 221 from expanding.

[0048] In the above-described embodiment, the press 120 is configured as a fine blanking press that performs plate thickness forming, dimple / hole forming, and punch forming in sequence in one stroke using one die set. However, this is not limited to this, and each forming process may be performed using a different die, such as a progressive press. [Industrial Applicability]

[0049] The present disclosure is applicable to the element manufacturing industry. [Explanation of symbols]

[0050] 1 continuously variable transmission, 3 primary pulley (pulley), 5 secondary pulley (pulley), 10 transmission belt, 12 laminated ring (ring), 20, 220 element, 21a, 221a saddle surface, 24, 224 slot portion, 25, 225 rocking edge, 100 element manufacturing device, 110 strip material (material), 132 punch, 132s slot forming portion, 133 plate holder, 142 die, 142s slot forming portion.

Claims

1. The present invention provides an element manufacturing device for manufacturing an element, which is arranged in an annular shape by an endless ring to constitute a transmission belt that is wound around a pair of pulleys of a continuously variable transmission, by pressing a plate-shaped material to manufacture the element, which has a slot portion, a saddle surface that contacts an inner peripheral surface of the ring inserted into the slot portion, and a rocking edge that serves as a fulcrum when adjacent elements contact each other and rotate relative to each other, the device comprising: The press working mold includes a die having an inner hole, a punch that is inserted into the inner hole of the die to punch out the material into the outer shape of the element, and a plate holder that is arranged opposite the die to sandwich and hold down the material, Both the die and the plate holder are provided with a slot forming portion that forms the slot portion, At least the slot forming portion of the die among the die and the plate holder protrudes beyond the portion other than the slot forming portion in a direction in which the die and the plate holder approach each other, When punching the slot portion, the blank is pressed by the die to move the plate holder, thereby starting the punching, and the slot forming portion is used to generate upset forming before the start of the punching. Element manufacturing equipment.

2. The manufacturing apparatus for the element according to claim 1, The slot forming portions of both the die and the plate holder protrude in a direction approaching each other beyond the other portions of the respective slot forming portions. Element manufacturing equipment.

3. The manufacturing apparatus for the element according to claim 1 or 2, The slot forming portion of the die has a taper formed at a corner portion on a side forming the saddle surface, The taper is such that the ratio of the clearance between the side surface of the die and the thickness of the material is 4%. and the ratio of the taper depth to the plate thickness of the material is 4% or more and 40% or less. Element manufacturing equipment.

4. A method for manufacturing an element, which constitutes a transmission belt that is wound around a pair of pulleys of a continuously variable transmission by being arranged in an annular manner using endless rings, the method comprising the steps of: manufacturing an element by pressing a plate-shaped material, the element having a slot portion, a saddle surface that contacts an inner peripheral surface of the ring inserted into the slot portion, and a rocking edge that serves as a fulcrum when adjacent elements contact each other and rotate relative to each other, the method comprising the steps of: The press working mold comprises a die having an inner hole, a punch that is inserted into the inner hole of the die to punch out the material into the outer shape of the element, and a plate holder that is arranged opposite the die to sandwich and hold down the material, and both the die and the plate holder are provided with a slot forming portion that forms the slot portion, and a mold is used in which at least the slot forming portion of the die and the plate holder protrudes further than the portions other than the slot forming portion in the direction in which the die and the plate holder approach each other, When punching the slot portion, the blank is pressed by the die to move the plate holder, thereby starting the punching, and the slot forming portion is used to generate upset forming before the start of the punching. A method for manufacturing elements.

5. A method for producing the element according to claim 4, comprising the steps of: The slot forming portions of both the die and the plate holder protrude in a direction approaching each other beyond the other portions of the respective slot forming portions. A method for manufacturing elements.

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