WO2019039272A1

WO2019039272A1 - Forging mold device and forging method

Info

Publication number: WO2019039272A1
Application number: PCT/JP2018/029688
Authority: WO
Inventors: 昌巳山口; 潤沼本; 友文小幡
Original assignee: Ntn株式会社
Priority date: 2017-08-21
Filing date: 2018-08-07
Publication date: 2019-02-28
Also published as: JP6798949B2; JP2019034326A

Abstract

In the present invention, an inner side joint member (143) of a constant speed universal joint (141) that has a track groove (147) which inclines with respect to a joint axis (n-n) is manufactured. The present invention comprises: a material inserting step (61) for inserting a material (W1) on the inner side of a die row (26); a closing step (62) for bringing upper and lower punches (23, 24) relatively close to one another; a molding step (63) for compressing the material by bringing the upper and lower punches even closer to one another; an opening step (64) for relatively separating the upper and lower punches; and a discharging step (65) for discharging the molded article obtained by the molding. In the material inserting step, the closing step, and the molding step, a closed state is set in which each die (25) of the die row is moved radially inward to cause the material to be set in a stable position, and in the opening step and the discharging step, an open state is set in which each die of the die row is moved radially outward.

Description

Forging die apparatus and forging method

The present invention relates to a forging die device and a forging method, and more particularly to a forging die device and a forging method for producing an inner joint member of a constant velocity universal joint having a track groove inclined with respect to a joint axis.

As an apparatus for manufacturing (forming) the inner joint member 1 of the constant velocity universal joint as shown in FIG. 24, a forging die apparatus described in Patent Document 1 etc. is known. The inner joint member 1 is formed of a disk-shaped body having an axial center hole 2, and on the outer diameter surface thereof, a track groove 3 having a curved groove bottom cross-sectional shape is formed at a predetermined pitch along the circumferential direction. As shown in FIGS. 25A and 25B and FIGS. 26A and 26B, this apparatus has a die row 6 in which a plurality of divided dies 5 are arranged in the circumferential direction, and a material W1 inserted inside the die row 6. It has a pair of upper and

lower punches

7, 8 and the like which are compressed in the axial direction. The die row 6 is disposed in a lower die (not shown) to which the lower punch 8 is attached, and the upper punch 7 is attached to an upper die (not shown).

The dividing die 5 is formed of a block body having a triangular shape in plan view in which a pair of

side surfaces

5a and 5a are tapered surfaces approaching from the device outer diameter side toward the device inner diameter side, and FIGS. 25A and 25B and FIGS. As shown in FIG. 26B, eight dies are arranged along the circumferential direction to form the die row 6. A track groove molding surface 5b and an outer surface molding surface 5c are provided in the inner diameter portion of each of the divided dies, and is always urged in the outer diameter direction by the elastic mechanism.

Therefore, in the free state, as shown in FIGS. 25A and 25B and FIGS. 26A and 26B, each of the divided dies 5 slides in the outer diameter direction, and between the divided dies 5 adjacent in the circumferential direction. A gap is provided. Therefore, on the inner diameter side of the die row 6, a space larger than the material (workpiece) W1 to be inserted is formed.

In the forging die set as described above, the die row 6 is opened as shown in FIGS. 25A and 25B and FIGS. 26A and 26B in which the divided dies 5 are slid in the outer diameter direction. The material W 1 is introduced into the space provided on the inner diameter side of the die row 6. In this case, the lower punch 8 is raised, and the lower punch 8 receives the material W1.

In this state, lower the upper mold. By this descent, the divided dies 5 of the die row 6 move in the inner diameter direction. Thereafter, the upper punch 7 is lowered and the lower punch 8 is raised, and the upper punch 7 presses the upper surface of the material W1 and the lower punch 8 presses the lower surface of the material W1. That is, the material W1 is compressed from above and below by the upper punch 7 and the lower punch 8. As a result, the material is plastically deformed in the space surrounded by the upper and

lower punches

7, 8 and forging is completed. That is, a forged material (not shown) is formed. After that, the forged material is taken out with the lower punch 8 as a knockout pin, with the forging die apparatus in the open state (the upper and lower molds are separated).

JP 2002-130325 A

The groove bottom has a curved track groove having an undercut shape (one having a linear portion and a curved portion), and the track groove is inclined with respect to the inner ring axial direction. When molding the inner joint member of a constant velocity universal joint having an angle, molding is performed according to the above-mentioned prior art, but the ratio of the materials (total height / diameter) becomes as small as 1.1 from the characteristics of the product shape.

Further, the dividing die 5 is expanded in diameter by an elastic mechanism (spring member) except at the time of molding in order to provide a sufficient gap so that the forged material in the undercut shape does not interfere in the discharging direction. When the material W1 is put there, the gap between the divided die and the material W1 is large and the possibility of becoming unstable is high. As a result, as shown in FIGS. 25A and 25B, insertion failure (in this case, the axis line WL of the material W1 is inclined with respect to the axis line L of the upper and lower punches 7 and 8) or as shown in FIGS. In addition, lateral collapse (a state in which the axis line WL of the material W1 is orthogonal to the axis line L of the upper and lower punches 7 and 8) or the like occurs. If such a defective insertion or falling sideways occurs, molding becomes impossible (mold breakage).

Therefore, in view of the above problems, according to the present invention, a forging die apparatus and a forging method capable of performing forging with high accuracy without causing insertion defects or lateral collapse of a material (work) upon material insertion. To provide

The forging die device of the present invention is a forging die device for manufacturing an inner joint member of a constant velocity universal joint having a track groove inclined with respect to a joint axis, and includes a plurality of divided dies along a circumferential direction. And a reciprocating mechanism for reciprocating the dies in the die row along the radial direction, and a pair of upper and lower punches for axially compressing the material inserted inside the die row. The reciprocation mechanism is controlled to move each die of the die row in the outer diameter direction to provide a gap between the adjacent dies along the circumferential direction, and each die of the die row in the inner diameter direction There is provided a control mechanism for moving at a desired timing to switch between a closed state in which adjacent dies are brought into close contact with each other along the circumferential direction, and at least when the material is inserted, the control mechanism performs each die in the die row in the inner diameter direction. Move it In which the closed state to maintain the timber in a stable posture.

According to the forging die device of the present invention, at the time of inserting the material, each die of the die row is moved in the inner diameter direction to maintain the material in a stable posture, so that the material is put in the closed state. It is possible to effectively prevent the occurrence of poor insertion or falling sideways.

The reciprocating mechanism may be constituted by a cylinder mechanism, and the operation of the cylinder mechanism may be controlled by the control mechanism. The cylinder mechanism may be a pneumatic cylinder or a hydraulic cylinder. The pneumatic cylinder has a simple structure and is easy to handle, can be inexpensive, and the response, size, weight, and information processing ability are average and balanced. The hydraulic cylinder is a cylinder that can be widely used from a very low speed to a high speed because it can generate a large force even with a small hydraulic pump, has a very high response speed, and is easy to control. Positioning can also be accurately controlled, and a large output is possible. It may be an electric cylinder or the like. The electric cylinder is an electrically driven cylinder composed of a ball screw, a linear guide, and an AC servomotor, and can be used like an air cylinder, it can be used with a simple wiring that does not require a pump and is connected to a power supply, and oil mist There are advantages such as no scattering and low running costs.

The inner joint member may be an undercut shape in which the track grooves adjacent in the circumferential direction are inclined in the opposite direction and the groove bottom longitudinal cross-sectional shape of each track groove has an arc portion and a straight portion.

The forging method of the present invention is a forging method of manufacturing an inner joint member of a constant velocity universal joint having a track groove inclined with respect to a joint axis, and a plurality of divided dies are disposed along a circumferential direction. A forging die apparatus comprising a die row, a reciprocating mechanism for reciprocating each die in the die row along a radial direction, and a pair of upper and lower punches for axially compressing a material inserted inside the die row Using a material feeding process to put the material inside the die row, a closing process to make the upper and lower punches relatively approach, a forming process to make the upper and lower punches further approach to compress the material, and the upper and lower punches The method further comprises: an opening step relatively spaced apart, and a discharging step discharging the formed molded product, and in the material charging step, the closing step and the molding step, each die of the die row is moved in the inner diameter direction to The stable figure Are closed to, in the opening step and the discharge step, it is an open state in which moving each die die row in the outer diameter direction.

According to the forging method of the present invention, in the material charging process, the closing process, and the forming process, each die in the die row is moved in the inner diameter direction to bring the material into a closed state to be in a stable posture. It is possible to effectively prevent the occurrence of poor insertion, falling sideways, etc. of the material. Further, in the opening step and the discharging step, each die of the die row is moved in the outer diameter direction to be in the open state, so that the forged finished product can be easily taken out from the forging die device.

In the present invention, it is possible to effectively prevent the insertion failure, the side fall, etc. of the inserted material. Therefore, forging (forming) with high accuracy can be performed. Further, in the opening step and the discharging step, each die of the die row can be moved in the outer diameter direction to be in an open state, and the forged finished product can be easily taken out from the forging die device, and the productivity Excellent.

It is a principal part expanded sectional view before the closing process of the forge metal mold | die apparatus of this invention. It is a principal part expanded sectional view which shows the discharge process of the forging die apparatus of this invention. It is a simplified view of a reciprocating mechanism. It is a simplified block diagram of the control circuit of the forging die device of the present invention. It is a block diagram of the work process of the forging method using the forging die device shown in FIG. It is a principal part expanded sectional view of a forge metallic mold apparatus before material input. It is a principal part expanded sectional view of a forging die device at the time of material injection. It is a principal part expanded sectional view of a forge metallic mold device at the time of contact of upper and lower molds. It is a principal part expanded sectional view of a forge metallic mold device at the time of closure of an upper and lower type. It is a principal part expanded sectional view of a forge metallic mold device at the time of molding. It is a principal part expanded sectional view of a forge metallic mold device at the time of top and bottom mold opening. It is a principal part expanded sectional view of a forging die device at the time of upper die rise. It is a principal part expanded sectional view of a forge metallic mold device at the time of discharge of a forged finished product. It is a top view of the dice row before material input. It is a top view of the dice row at the time of material injection. It is a top view of the dice row in the state where the upper and lower dies are in contact with the material. It is a top view of the dice row at the time of closure of an up-and-down type. It is a top view of the dice row at the time of molding. It is a top view of the dice row at the time of upper and lower mold opening. It is a top view of the dice row at the time of upper die rise. It is a top view of the dice row at the time of a forged finished product discharge. It is a longitudinal cross-sectional view of the constant velocity universal joint using the inner joint member formed by forging with the forging die device according to the present invention. It is a front view of the constant velocity universal joint shown in FIG. It is the perspective view which partially omitted the inner joint member of the constant velocity universal joint. The die row at the time of the material injection | throwing-in to the conventional forging die apparatus is shown, and it is a top view of an insertion defect state. The die row at the time of the material injection | throwing-in to the conventional forging die apparatus is shown, and it is sectional drawing of an insertion defect state. The die row at the time of the material injection | throwing-in to the conventional forging die apparatus is shown, and it is a top view of a side fall state. The die row at the time of the material injection | throwing-in to the conventional forging die apparatus is shown, and it is sectional drawing of a fall state.

Hereinafter, an embodiment of the present invention will be described based on FIGS. 1 to 23. 1 and 2 show a cross-sectional view of the main part of a forging die device according to the present invention. This forging die apparatus is for forging and forming the inner joint member 143 of the constant velocity universal joint 141 shown in FIG. 22 and FIG.

The constant velocity universal joint 141 has a plurality of outer joint members 142 in which a plurality of track grooves 147 extending in the axial direction are formed in the spherical inner circumferential surface 146 and a plurality of pairs of track grooves 147 of the outer joint member 142 in the spherical outer circumferential surface 148. Of the inner joint member 143 in which the track groove 149 is formed, and a plurality of balls as torque transmission members that transmit torque by being interposed between the track groove 147 of the outer joint member 142 and the track groove 149 of the inner joint member 143 144 and a holder 145 for holding the ball 144. The cage has a spherical outer circumferential surface 152 and a spherical inner circumferential surface 153 fitted respectively to the spherical inner circumferential surface 146 of the outer joint member 142 and the spherical outer circumferential surface 148 of the inner joint member 143.

In the constant velocity universal joint 141, the track groove 147 of the outer joint member 142 includes the joint center O at a working angle of 0 ° and is separated by a plane (joint central plane) orthogonal to the joint axis n-n The back side and the opening side are respectively made into the circular arc part 147a and the linear part 147b which make the joint center O a curvature center. On the other hand, the track groove 149 of the inner joint member 143 is such that the opening side and the back side with the joint center plane as an arc portion 149a and a straight portion 149b whose center of curvature is the joint center O, respectively.

Then, as shown in FIG. 23, the

track grooves

147 and 149 are each inclined in the circumferential direction with respect to the axis of the joint, and the

track grooves

147A and 147B and 149A and 149B whose inclination directions are adjacent to each other in the circumferential direction mutually It is formed in the opposite direction. Therefore, the arc portion 147a of the track groove 147A is called an arc portion 147Aa, the straight portion 147b of the track groove 147A is called an arc portion 147Ab, and the arc portion 147a of the track groove 147B is called an arc portion 147Ba, and the straight line of the track groove 147B. The part 147b is called an arc part 147Bb. The arc portion 149a of the track groove 149A is called an arc portion 149Aa, the straight portion 149b of the track groove 149A is called an arc portion 149Ab, and the arc portion 149a of the track groove 149B is called an arc portion 149Ba, and the straight portion of the track groove 149B. The portion 149b is called an arc portion 149Bb.

A ball 144 is disposed at each intersection of the pair of

track grooves

147A, 149A and 147B, 149B of the outer joint member 142 and the inner joint member 143. Therefore, when the

joint members

142 and 143 rotate relative to each other at an operating angle of 0 ° as shown, the wedge angle formed between the

track grooves

147A and 149A is opened and 147B and 149B. The cage 145 is stable at the joint center O position, since the direction in which the wedge angle opens is opposite to each other, and forces in opposite directions from the ball 144 act on the pocket portions 145a adjacent in the circumferential direction of the cage 145 Do. Therefore, the contact force between the spherical outer circumferential surface 152 of the cage 145 and the spherical inner circumferential surface 146 of the outer joint member 142 and the contact between the spherical inner circumferential surface 153 of the cage 145 and the spherical outer circumferential surface 148 of the inner joint member 143 As a result of suppressing the force and improving the operability of the joint, torque loss and heat generation are suppressed, and the durability is improved.

The forging die device of the present invention is a cylindrical material (work) W1 made of carbon steel etc. shown in FIG. 1 etc., having a finished shape of the track groove 149 and a shape having a spherical outer surface, ie, FIG. The inner joint forging 143 'of the shape will be forged. Then, as shown in FIG. 10 and the like, the forged material W obtained by this forging is a non-penetrated material in which the inner diameter hole 19 has a bottom wall 20 in the middle in the axial direction. For this reason, the bottom of the forged material W is punched out in a press process or removed by turning, a female spline is formed in the inner diameter hole, and the width surface and the spherical outer surface are finished by machining such as turning or grinding. Furthermore, the inner joint member 143 of the constant velocity universal joint is formed by machining details such as the opening edge of the inner diameter hole and heat treatment. The inner joint forged product 143 'is a component which has not been subjected to machining finish processing and heat treatment, and has the same shape as the conventional inner joint member 1 of the constant velocity universal joint. Therefore, in FIG. 24 showing the conventional inner joint member 1, reference numeral 143 'of the inner joint forged product forged by the forging die device of the present invention is attached.

As shown in FIG. 6, the forging die apparatus includes an upper die 21, a lower die 22, an upper punch member 23 disposed on the upper die 21 side, and a lower punch member disposed on the lower die 22 side. 24 and a die row 26 and the like disposed on the lower die 22 side.

The upper die 21 can be raised and lowered by an upper die lifting drive mechanism K1 (see FIG. 4) such as a hydraulic cylinder. Further, the upper mold 21 is formed with a hole 27 in which the upper punch member 23 is accommodated so as to be able to move up and down. The upper punch member 23 is moved up and down by the upper punch vertical movement mechanism U1 (see FIG. 4) such as a hydraulic cylinder. It is made movable. The upper punch member 23 has a punch body 23a, an upper ring punch 23b disposed on the outer peripheral side of the punch body 23a, and a boss portion 23c for receiving these, as shown in FIGS. 6 to 13 and the like. A guide structure 28 for guiding the upper punch member 23 is provided on the inner diameter surface of the hole 27.

The lower die 22 can be raised and lowered by a lower die elevating drive mechanism K2 (see FIG. 4) such as a hydraulic cylinder. Further, the lower die 22 is formed with a hole 30 in which the lower punch member 24 is accommodated so as to be able to move up and down. The lower punch member 24 is moved up and down by the lower punch up and down movement mechanism U2 (see FIG. 4) It is made movable. As shown in FIGS. 1 and 2, the lower punch member 24 has a punch body 24a, a ring punch 24b disposed on the outer peripheral side of the punch body 24a, and a boss 24c for receiving these. A guide structure 31 for guiding the lower punch member 24 is provided on the inner diameter surface of the hole 30.

As shown in FIGS. 14 and 15, the die row 26 disposed on the lower die 22 side includes a plurality of (eight in the illustrated example) divided dies 25 disposed along the circumferential direction. . Each dividing die 25 is formed of a block body having a triangular shape in a plan view, in which the pair of

side surfaces

25a, 25a are tapered surfaces approaching from the apparatus outer diameter side toward the apparatus inner diameter side.

The side surfaces 25a, 25a extend in the radial direction, and as shown in FIGS. 14 and 15, the side surfaces facing each other of the division dies 25 adjacent to each other in the circumferential direction are in contact or in close contact by sliding to the center of the apparatus. In the state, the die row 26 has a ring shape in plan view. Further, on the inner diameter portion of each divided die of this die row 26, the track groove forming mold surface 25b and the outer diameter surface forming mold surface 25c are provided at a predetermined pitch. The outer diameter portion of each of the divided dies 25 is a tapered surface portion 29 whose diameter increases in the outer diameter direction from the upper side to the lower side. The tapered surface portion 29 includes a central first portion 29a, a pair of

second portions

29b and 29b on both sides of the first portion 29a, and a pair of

side portions

29c and 29c provided continuously with the

second portions

29b and 29b. It consists of

Each of the divided dies 25 reciprocates in the radial direction via a reciprocating mechanism M as shown in FIG. 1 and FIG. The reciprocating mechanism M is constituted by a cylinder mechanism M1. The cylinder mechanism M1 in this case is a single acting cylinder provided with a cylinder tube 32, a piston rod 33 fitted in the cylinder tube 32, and a spring 34 accommodated in the cylinder tube 32.

The cylinder tube 32 is provided with a first chamber 35 and a second chamber 36. That is, the cylinder tube 32 includes a main body portion 32a formed of a bottomed cylindrical body, and a lid member 32b provided at the opening of the main body portion 32a, and a concave portion of the bottom wall 32a1 of the main body portion 32a is provided. The second chamber 36 is configured. Further, the first chamber 35 is configured between the lid member 32 b and the bottom wall 32 a 1 of the main body 32 a.

The piston rod 33 includes a piston portion 33a and a shaft body 33b. The piston portion 33a is fitted in the first chamber 35 so as to be capable of reciprocating, and the shaft body 33b is inserted from the first chamber 35 through the through hole of the lid member 32b. Project outside. A spring 34 is interposed between the piston 33a and the lid 32b. Therefore, in the free state, as shown in FIG. 1, the piston rod 33 is pressed by the elastic force of the spring 34, and the piston portion 33a is in contact with the bottom wall 32a1 of the main portion 32a.

A connecting member 37 connected to the split die 25 is attached to the projecting end of the shaft body 33 b of the piston rod 33. The connecting member 37 is attached to the projecting end of the shaft body 33b of the piston rod 33 via the bolt member 40 and extends axially in the first portion 37a, and a second portion extending in the radial direction from the first portion 37a. A third portion 37c extends in the axial direction (vertical direction) from the second portion 37b, and the third portion 37c is connected to the divided die 25 via the bolt member 41. The dividing dies 25 are provided on the lower die 22 and received by the receiving table 42.

A hydraulic pressure passage 39 is connected to the second chamber 36, and the hydraulic pressure is supplied from the hydraulic pressure passage 39 to the second chamber 36. For this reason, in the state shown in FIG. 1 (in the state where the hydraulic pressure is not supplied to the second chamber 36 and the piston 33a is in contact with the bottom wall 32a1 of the main body 32a), the dividing die 25 has an inner diameter By moving in the direction, as shown in FIG. 14 and FIG. 15, the die row 26 in a state in which the mutually facing side surfaces 25a of the adjacent divided dies 25 along the circumferential direction are in contact is in a closed state.

If hydraulic pressure is supplied to the second chamber 36 from the state shown in FIG. 1, the piston rod 33 moves in the outer diameter direction as shown in FIG. By moving in this manner, the divided dies 25 connected via the connecting member 37 move in the outer diameter direction, and the die row 26 is in the open state (the side faces of the adjacent divided dies 25 facing in the circumferential direction) A state in which a gap is formed between 25a and 25a (the state shown in FIGS. 19 to 21 etc.) is obtained.

By the way, as shown in FIG. 3, the cylinder mechanism M1 is connected to each of a plurality of (in this case, eight) division dies 25 along the circumferential direction. A hydraulic path 39 is connected to each cylinder mechanism M1. A hydraulic pressure tank 45, a pressure reduction control valve 46, a control valve 47,

shuttle valves

48 and 49, and the like are disposed in the hydraulic pressure passage 39, and a hydraulic circuit H is formed.

Further, as shown in FIG. 6 and the like, a die base 50 is disposed in the upper mold 21, and an upper plate 51 is provided inside the die base 50. The die base 50 has a plurality of recesses 52 into which the outer diameter end of each of the divided dies 25 is fitted. The inner surface of the recesses 52 is a die guide along the outer diameter of the divided dies 25. The surface 53 is formed. That is, the die guide surface 53 is a surface that presses the divided die 25 in the inner diameter direction by the axial movement of the die base 50.

This apparatus comprises a control mechanism (control means) 55 as shown in FIG. It can be configured by a microcomputer or the like in which a ROM (Read Only Memory), a RAM (Random Access Memory), etc. are connected via a bus, centering on a CPU (Central Processing Unit). Further, the control mechanism 55 is provided with a storage device as storage means, and timing of vertical movement of the upper and

lower molds

21 and 22, timing of vertical movement of the

vertical punch members

23 and 24, timing of switching to the control valve 47 of the hydraulic circuit H Etc. are stored in advance. A storage device as a storage means is composed of an HDD (Hard Disc Drive), a DVD (Digital Versatile Disk) drive, a CD-R (Compact Disc-Recordable) drive, an EEPROM (Electronically Erasable and Programmable Read Only Memory), and the like. The ROM stores programs and data to be executed by the CPU. That is, the timing control of the vertical movement of the upper and lower dies 21 and 22, the vertical movement of the vertical punch, and the opening and closing movement of the die row is performed.

The forging method of the present invention, as shown in FIG. 5, includes the material charging step 61, the closing step 62, the forming step 63, the opening step 64, and the discharging step 65 using the above-described forging die device. . In the material introduction process 61, the material is transferred to the forging die apparatus with the die array 26 closed, in the preparation process (before material introduction (closed)) in which the die array before the material introduction to the forging die apparatus is closed. There is a charging process (when material is inserted (closed)) for charging. In the closing step 62, the upper and lower molds are made relatively close to each other in the step of bringing the upper and

lower molds

21 and 22 into contact with the material while keeping the die row 26 closed. There is a step of closing the mold apparatus (upper and lower mold closing time (closed)). The forming step 63 is a step of forming the upper and

lower punch members

23 and 24 close to each other (during forming (closed)). In the opening step 64, the upper and lower dies 21 and 22 are separated from each other to open the die row (upper and lower dies open (open)), and the upper die 21 is raised with the die row 26 kept open. There is a process (upper mold rise time (open)). The discharging step 65 is a step of discharging the forged material from the mold apparatus (during work discharge (open)). Note that (closed) in each step in FIG. 5 means that the die row 26 is in a closed state (the elastic force of the spring 34 does not supply the hydraulic pressure to the second chamber 36 of the cylinder mechanism M1). And the division die 25 is moved in the inner diameter direction), and (open) of each process in FIG. 5 is a state where the die row 26 is in an open state (the second state of the cylinder mechanism M1). The hydraulic pressure is supplied to the chamber 36, and the piston rods 33 are moved in the outer diameter direction against the elastic force of the spring 34 to move the divided dies 25 in the outer diameter direction. ing.

Next, steps shown in FIG. 5 will be described with reference to FIGS. 6 to 13 and FIGS. 14 to 21. First, as shown in FIG. 6, the upper and

lower molds

21 and 22 are separated from each other to open the mold apparatus. At this time, the lower punch member 24 is lowered. Further, without supplying hydraulic pressure to the second chamber 36 of the cylinder mechanism M1, the piston rod 33 is moved in the inner diameter direction by the elastic force of the spring 34 to move each of the divided dies 25 in the inner diameter direction. Move 25 in the inward direction. That is, as shown in FIG. 14, the die row closed state in which the side surfaces of the divided dies 25 adjacent in the circumferential direction are in contact with each other. This is a preparation process (before material input (closed)).

In this state, as shown in FIG. 7, an insertion step (during material insertion (close)) of inserting a cylindrical material (workpiece) W1 into the inside of the die row 26 is performed. As described above, when the material W1 is introduced, the lower surface W1a of the material W1 is received by the upper surface 24a1 of the punch main body 24a of the lower punch member 24, and the outer peripheral surface W1c of the material W1 is a die as shown in FIG. The inner surface of the row 26 is in contact. As a result, the material W1 is held at the normal position where the axis thereof coincides with the axis of the upper and

lower punch members

23 and 24.

Next, as shown in FIG. 8, the upper die 21 and the lower die 22 are relatively approached to bring the lower surface 23 a 1 of the punch body 23 a of the upper punch member 23 into contact with the upper surface W 1 b of the material W 1. That is, the upper and lower mold contact (closed) state of the closing step 62 shown in FIG. 5 is set. Thereafter, as shown in FIG. 9, the upper punch member 23 and the lower punch member 24 are brought closer to each other. Thereby, the lower part of the upper punch member 23 is fitted to the concave part formed on the upper surface W1b of the material W1, and the upper part of the lower punch member 24 is fitted to the concave part formed on the lower surface W1a of the material W1, ie, The upper and lower type closing (closing) shown in FIG. 5 is performed. In the state shown in FIGS. 8 and 9, as shown in FIGS. 16 and 17, the outer peripheral surface W1c of the material W1 is in contact with the inner diameter surface portion of the die row 26.

Next, as shown in FIG. 10, the upper punch member 23 and the lower punch member 24 are brought closer to each other, and the forged material W (in which the inner diameter hole 19 has the bottom wall 20 at the middle in the axial direction) Is molded as shown in FIG. That is, the molding (closing) shown in FIG. 5 is performed. In this case, in the upper punch member 23, the lower surface 23b1 of the upper ring punch 23b is retracted upward with respect to the lower end portion of the punch main body 23a, and the lower punch 23b is lower than the upper end portion of the lower punch member 24. I'm going back.

Therefore, the inner hole 19 with the bottom wall 20 is formed at the lower end portion of the punch main body 23a of the upper punch member 23 and the upper end portion of the punch main body 24a of the lower punch member 24. The lower surface 23b1 (see FIG. 6) forms the upper surface Wb of the forged material (forged work) W, and the upper surface 24b1 (see FIG. 1) of the lower ring punch 24b of the lower punch member 24 corresponds to the lower surface of the forged work W Form Wa. Thereafter, as shown in FIG. 11, the upper and lower dies 21 and 22 are separated, and the divided dies 25 of the die row 26 are slightly slid in the outer diameter direction to open the die row 26 as shown in FIG. State (The hydraulic pressure is supplied to the second chamber 36 of the cylinder mechanism M1, and the piston rod 33 is moved in the outer diameter direction against the elastic force of the spring 34, and the divided dies 25 are moved in the outer diameter direction. State). That is, the upper and lower molds are open (opened) shown in FIG. In the open state shown in FIG. 19, the split die 25 can be slid further in the outer diameter direction.

Thereafter, as shown in FIG. 12, the upper and lower dies 21 and 22 are separated to raise the upper punch member 23, and as shown in FIG. In the open state (the hydraulic pressure is supplied to the second chamber 36 of the cylinder mechanism M1, and the piston rod 33 is moved in the outer diameter direction against the elastic force of the spring 34 to move the divided dies 25 in the outer diameter direction). State). That is, it is assumed that the upper mold of FIG. 5 is lifted (opened). Next, as shown in FIG. 13, the lower punch member 24 is raised to take out the forged work W (in this state, the die row 26 is in the state shown in FIG. 21). That is, it is assumed that the work is discharged (opened) in FIG. By this, forging processing is completed.

According to the forging die apparatus of the present invention, when the material is introduced, the dies 25 of the die row 26 are moved in the inner diameter direction to keep the material W1 in a stable posture, so that the material W1 is closed. It is possible to effectively prevent the occurrence of the insertion failure of the material W1 and the side fall.

It is possible to effectively prevent the insertion failure and the side fall of the inserted material W1. For this reason, highly accurate manufacturing (molding) can be performed. Further, in the opening step 64 and the discharging step 64, each die 25 of the die row 26 can be moved in the outer diameter direction to be in an open state, and a forged workpiece (forged material) W which is a forged finished product It is easy to take out from the forging die device, and the productivity is excellent. Further, in the material introduction process 61, the closing process 62, and the forming process 63, each die 25 of the die row 26 is moved in the inner diameter direction to bring the material into a closed state. While being inclined with respect to the above, even in the undercut shape, the occurrence of the insertion failure, the side fall, etc. can be effectively prevented, and the stable forging (forming) can be performed.

The reciprocating mechanism M is configured by the cylinder mechanism M1, and the operation of the cylinder mechanism M1 can be controlled by the control mechanism 55. The cylinder mechanism M1 may be a pneumatic cylinder or a hydraulic cylinder. The pneumatic cylinder has a simple structure and is easy to handle, can be inexpensive, and the response, size, weight, and information processing ability are average and balanced. The hydraulic cylinder is a cylinder that can be widely used from a very low speed to a high speed because it can generate a large force even with a small hydraulic pump, has a very high response speed, and is easy to control. Positioning can also be accurately controlled, and a large output is possible. It may be an electric cylinder or the like. The electric cylinder is an electrically driven cylinder composed of a ball screw, a linear guide, and an AC servomotor, and can be used like an air cylinder, it can be used with a simple wiring that does not require a pump and is connected to a power supply, and oil mist There are advantages such as no scattering and low running costs.

The embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment, and various modifications are possible. The number of track grooves in the inner joint member can be arbitrarily increased or decreased. The groove bottom is not limited to the undercut shape, and the groove bottom may be an arc portion only. That is, increase and decrease of the number of divided dies 25 of the die row 26 is arbitrary, and the shapes of the track groove forming surface 25b and the outer diameter surface forming surface 25c can be arbitrarily set.

When the upper and lower dies 21 and 22 are moved close to each other, the upper die 21 is fixed even if the lower die 22 is fixed and only the upper die 21 is moved up and down or both of the upper and lower dies 21 and 22 are moved up and down. Only the lower mold may be moved up and down. When the upper and

lower punch members

23 and 24 are moved close to and away from each other, the lower punch member 24 is fixed and only the upper punch member 23 is moved up and down, or both of the upper and

lower punch members

23 and 24 are moved up and down. The upper punch member 23 may be fixed and only the lower punch member 24 may be moved up and down.

Further, in the embodiment, the die row 26 is closed in the material loading step 61, the closing step 62, and the forming step 63, and the die row 26 is opened in the opening step 64 and the discharging step 65. It is preferable to configure in this way for high precision forging. However, since the control mechanism (control means) 55 can switch between the open state of the die row 26 and the closed state of the die row 26 at a desired timing, the die is inserted at least in the material loading step 61. Since the row 26 only needs to be in the closed state, the die row 26 can be closed or opened in another process.

The constant velocity universal joint can be applied to a fixed type constant velocity universal joint of an undercut free type or a fixed type constant velocity universal joint of a Barfield type. Further, it may be a cross groove type sliding constant velocity universal joint. When the cross groove type constant velocity universal joint is used, it may be a float type or non-float type, and when it is a tripod type, it may be a single roller type or a double roller type.

23 Upper punch member 24 Lower punch member 25 Divided die 25a Side surface 26 Die row 55 Control mechanism 61 Raw material input process 62 Closed process 63 Open process 65 Discharge process 143 Inner joint member 149 Track groove 149a Arc part 149b Straight part M Reciprocation Dynamic mechanism M1 Cylinder mechanism W1 Material (work)
W Forged material (forged work)

Claims

A forging die apparatus for manufacturing an inner joint member of a constant velocity universal joint having a track groove inclined with respect to a joint axis, comprising:
A die row in which a plurality of divided dies are arranged along the circumferential direction, a reciprocating mechanism for reciprocating each die of the die row along the radial direction, and an axial direction of a material loaded inside the die row And a pair of upper and lower punches to compress
The reciprocation mechanism is controlled to move each die in the row of dies in the outer diameter direction to open a gap between adjacent dies along the circumferential direction, and to move each die in the row of dies in the inner diameter direction A control mechanism for switching at a desired timing the switching between a closed state in which adjacent dies are in close contact with each other along the circumferential direction, the control mechanism moving at least each die in a row of dies in an inner diameter direction A forging die apparatus characterized in that it is in a closed state in which the material is maintained in a stable posture.
2. The forging die apparatus according to claim 1, wherein the reciprocating mechanism is a cylinder mechanism, and the operation of the cylinder mechanism is controlled by the control mechanism.
The inner joint member is characterized in that the inclination directions of the track grooves adjacent in the circumferential direction are formed in opposite directions, and the groove bottom longitudinal cross-sectional shape of each track groove is an undercut shape having an arc portion and a straight portion. The forging die apparatus according to claim 1 or claim 2.
A forging method of manufacturing an inner joint member of a constant velocity universal joint having a track groove inclined with respect to a joint axis, comprising:
A die row in which a plurality of divided dies are arranged along the circumferential direction, a reciprocating mechanism for reciprocating each die of the die row along the radial direction, and an axial direction of a material loaded inside the die row Using a forging die device equipped with a pair of upper and lower punches
The material feeding process for charging the material into the die row, the closing process for relatively bringing the upper and lower punches closer, the forming process for compressing the material by further bringing the upper and lower punches closer, and the upper and lower punches The apparatus comprises: an opening process for separating the material and a discharging process for discharging the molded product which has been molded. In the material charging process, the closing process and the molding process, each die of the die row is moved in the inner diameter direction to stabilize the material. A forging method characterized in that in a closed state, in the opening step and the discharging step, each die of the die row is moved in an outer diameter direction.
The inner joint member is characterized in that the inclination directions of the track grooves adjacent in the circumferential direction are formed in opposite directions, and the groove bottom longitudinal cross-sectional shape of each track groove is an undercut shape having an arc portion and a straight portion. The forging method according to claim 4.