JP2013049094A - Plastic working apparatus for metallic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce manufacturing cost by improving yield by preventing the occurrence of a micro crack starting from a groove bottom of a fracture surface when an annular third intermediate material 21 is diametrically enlarged by form rolling to form a fourth intermediate material 22.SOLUTION: After a circular recess 45 is formed by rocking die forging on one side of a disk-shaped first intermediate material 19, a center portion thereof is punched from the side opposite from the circular recess 45 to form the third intermediate material 21. A fracture surface formed on an inner circumferential surface due to the punching is located at an axial-direction intermediate portion. The fracture surface is squeezed in the initial stage of the rolling work and formed in a smooth surface. Thus, in the stage at which the diameter of the third intermediate material 21 is enlarged, any groove forming a starting point of the occurrence of crack is not present on an inner circumferential surface of the third intermediate material 21.

Description

  The present invention relates to a method for manufacturing a metal ring-shaped part such as a bearing ring for a radial rolling bearing, and an improvement of a manufacturing apparatus used directly for carrying out this manufacturing method. Specifically, the metal ring-shaped part as described above is improved at a low cost, and the yield is improved by preventing the occurrence of damage such as cracks in the manufacturing process. This is intended to further reduce the manufacturing cost of the shaped parts.

For example, in order to obtain a metal ring-shaped part such as a bearing ring (outer ring, inner ring) constituting a radial rolling bearing incorporated in a rotation support portion of various industrial machines such as a rolling mill at low cost, It is conceivable to manufacture by a manufacturing method as shown in FIG.
In this manufacturing method, first, a cylindrical material 1 as shown in FIG. 13A is obtained by cutting a long material into a predetermined length. Next, the material 1 is crushed in the axial direction to form a disc-shaped first intermediate material 2 as shown in FIG. Next, the central portion on one side of the first intermediate material 2 is punched and removed by pressing to obtain an annular second intermediate material 3 as shown in FIG. Next, the diameter of the second intermediate material 3 is expanded by rolling to obtain an annular third intermediate material 4 as shown in FIG. Furthermore, a metal to be produced such as a finish rolling process for forming the raceway surface, a heat treatment process for hardening the raceway surface, and a grinding process for improving the surface roughness of the raceway surface on the third intermediate material 4 A predetermined finishing process is performed depending on the ring-shaped part made of metal, so that the ring-shaped part made of metal such as the bearing ring is obtained.

  However, in the case of manufacturing a metal ring-shaped part having a large diameter (for example, an outer diameter of 200 mm or more) in the process as described above, the first intermediate material 2 shown in FIG. In the process of making the second intermediate material 3 shown in (C), there is a possibility that a minute crack may occur on the inner diameter side of the intermediate material and the intermediate material may have to be discarded as a defective product. It was found by the inventors' research. This point will be described with reference to FIGS.

  As shown in (B) → (C) of FIG. 13, the work of punching out the central portion of the first intermediate material 2 to form the second intermediate material 3 is performed as shown in FIGS. 14 (A) → (B) → (C). As shown in FIG. 5, the punch 6 is pressed against the central portion of the upper surface of the first intermediate material 2 while the lower intermediate diameter portion of the first intermediate material 2 is held by the die 5. In the process of this punching operation, as shown in FIGS. 14A to 14B, as the punch 6 is pushed, the outer peripheral edge of the punch 6 is abutted on the upper surface of the first intermediate material 2. Cracks 7a from the contacting portion and the portion of the lower surface of the first intermediate material 2 that is in contact with the inner peripheral edge of the die 5 toward the center in the thickness direction of the first intermediate material 2; 7b occurs (runs). Then, at the moment when the tips of both cracks 7a and 7b are continuous, the central portion of the first intermediate material 2 is separated from the portion near the outer diameter, and this central portion is discharged as scrap 8, and the portion closer to the outer diameter. Is the second intermediate material 3.

  On the inner peripheral surface of the center hole 13 of the second intermediate material 3 obtained in this way, as shown in FIG. 15, the sagging 9 and the shearing surface 10 are sequentially formed from the upper side that is the pushing side of the punch 6. Then, the fracture surface 11 and the burrs 12 exist. Of these, the fracture surface 11 is a surface formed by the cracks 7a and 7b shown in FIG. For this reason, the surface of the fracture surface 11 is a rough surface having a large surface roughness and a sawtooth shape in cross section as shown in FIG. When the annular second intermediate material 3 is formed by the method shown in FIGS. 13B to 13C and FIG. 14, the fracture surface 11 as described above becomes the center hole 13 of the second intermediate material 3. It will be in the state which exists in the part near opening edge part.

  In particular, when producing a large-diameter ring-shaped part having an outer diameter of 200 mm or more, for example, the second intermediate material 3 as described above is expanded by a cold rolling processing apparatus 14 as shown in FIG. When the diameter is increased, minute cracks 17 and 17 are likely to be generated from the broken surface 11 as shown in FIG. First, in the cold rolling process, the second intermediate material 3 is externally fitted to a mandrel 15 that is rotatably supported and constitutes the cold rolling apparatus 14, and the outer peripheral surface of the second intermediate material 3 is fitted. The pressing is performed by rotating the forming roll 16 while pressing the forming roll 16. When such a cold rolling process is performed, a portion of the fracture surface 11 near the opening end portion of the center hole 13 is not sufficiently pressed by the mandrel 15 and the fracture of this portion is not performed. The cross-section 11 is greatly expanded as the diameter of other portions is increased without being sufficiently crushed by the mandrel 15 (without being subjected to a load in the compression direction to be a smooth surface). As a result, as shown in FIG. 16B, a minute crack starting from the groove bottom portion of the fracture surface 11 from a portion near the opening end of the center hole 13 in a part of the fracture surface 11. 17 and 17 are considered to occur.

JP-A-1-317650 Japanese Patent Laid-Open No. 3-110038 JP-A-8-47741 Japanese Patent Laid-Open No. 10-5919 JP 2000-117379 A Japanese Patent No. 3692635

  The present invention improves the yield by preventing the occurrence of minute cracks, which are considered to be caused by the above-mentioned causes, particularly when manufacturing a metal ring-shaped part having a large diameter (for example, an outer diameter of 200 mm or more). The invention was invented to further reduce the manufacturing cost of the ring-shaped parts.

Among the metal ring-shaped part manufacturing method and metal part plastic processing apparatus of the present invention, the metal ring-shaped part manufacturing method is a method in which a cylindrical material is first squeezed in the axial direction by upsetting and circular. It is a plate-like first intermediate material.
Thereafter, a circular recess is formed in the central portion of the first axial surface by a rear extrusion process in which the central portion on one side of the first intermediate material is crushed in the axial direction and a portion closer to the outer diameter of the axial direction is protruded in the direction opposite to the crushing direction. The second intermediate material has.
Subsequently, in the state where the outer diameter portion of the second intermediate material on one side in the axial direction is closer to the outer diameter than the circular recess, the second intermediate material is pressed against the central portion on the other side in the axial direction by pressing the punch. A portion corresponding to the circular recess is punched and removed at the center of the material to form an annular third intermediate material.
Next, the diameter of the third intermediate material is expanded by rolling to obtain an annular fourth intermediate material.
Further, a predetermined finishing process is applied to the fourth intermediate material to form a metal ring-shaped part.

In the case of carrying out such a method for producing a metal ring-shaped part of the present invention, preferably, in addition to the portion near the outer diameter in the axial direction of the second intermediate material, as in the invention described in claim 2, The second intermediate material is brought into a compressed state (hydrostatic pressure state) by suppressing the outer peripheral surface, the inner peripheral surface of the circular recess, and the portion near the outer diameter of the other surface in the axial direction. In this state, a punch is pressed against the second intermediate material.
When carrying out such a method for manufacturing a metal ring-shaped part according to claim 2, more preferably, as in the invention according to claim 3, the first intermediate material is combined with the second intermediate material. The backward extrusion is performed by swing forging. This oscillating forging has a central axis inclined with respect to the central axis of both intermediate materials on one axial surface of both intermediate materials in a state where the outer peripheral surface and the other axial surface of both intermediate materials are suppressed, It is performed by pressing a roll whose processing surface is in a direction perpendicular to the central axis of both the intermediate materials in the direction of the portion in contact with the first intermediate material. And the part near the outer diameter of the one axial side surface of the second intermediate material and the entire other axial surface are flat surfaces perpendicular to the central axis of the second intermediate material.

Further, when the metal ring-shaped part manufacturing method of the present invention as described above is carried out, preferably, as in the invention described in claim 4, the material is crushed in the axial direction to form the disk-shaped member. The first intermediate material is processed by swing forging. This rocking forging is a center tilted with respect to the central axis of these materials or the first intermediate material on one side in the axial direction of the material with the material stored in a die that regulates the outer peripheral surface of the first intermediate material. This is performed by pressing a roll having a shaft, and a direction of a portion of the processing surface that is in contact with the material or the first intermediate material is perpendicular to the central axis of the material or the first intermediate material.
More preferably, as in the inventions described in claims 5 to 7, at least one of the rotation speed and the stroke speed of the tool to be used is adjusted by servo control in the rolling process or the swing forging. The stroke speed is adjusted by using a press machine that servo-controls the ram stroke.

On the other hand, the metal parts plastic working apparatus (die set) of the present invention includes a lower plate, a holding portion, an upper plate, a processing tool, and an electric motor.
Of these, the lower plate is placed on the upper surface of the processing table of the press machine.
The holding portion is for holding a workpiece and is provided on the upper surface of the lower plate.
The upper plate is installed on the lower surface of the ram of the press machine above the lower plate and pressed downward by the ram of the press machine.
Moreover, the said processing tool is provided in the lower surface of the said upper board, and presses the said to-be-processed object as this upper board falls.
Further, the electric motor is for rotationally driving the processing tool, and is supported and fixed to a part of the upper plate.

In order to use the metal part plastic working apparatus of the present invention as described above for carrying out the method of manufacturing the metal ring-shaped part of the present invention described above, specifically, for example, the invention described in claim 9 As described above, the holding portion is a die having an inner peripheral surface shape that matches the outer peripheral surface shape at the time when the processing of the workpiece is completed. The processing tool is a roll for plastically deforming the workpiece by swing forging.
Alternatively, as in the invention described in claim 10, the holding portion is a mandrel that is disposed in the horizontal direction and rotates in a state in which an annular workpiece is loosely fitted. The processing tool is a forming roll that rotates while pressing the workpiece against the mandrel, and expands the diameter of the workpiece by rolling.
Preferably, as in the invention described in claim 11, the electric motor is a servo motor capable of adjusting the rotation speed, or the upper plate is pressed as in the invention described in claim 12. It is assumed that a press machine equipped with a ram that has a function of servo-controlling the stroke of the ram.

According to the method for manufacturing a metal ring-shaped part of the present invention as described above, a metal ring-shaped part such as a bearing ring constituting a large-diameter radial rolling bearing having an outer diameter of 200 mm or more can be manufactured at low cost. In the process of carrying out the manufacturing method, it is possible to prevent the occurrence of damage such as cracks, improve the yield, and further reduce the manufacturing cost of the metal ring-shaped part.
First, in the case of the method for manufacturing a metal ring-shaped part according to the present invention, the second intermediate material is made into an annular third intermediate material, and the central portion of the second intermediate material is punched and removed. The fracture surface generated on the inner peripheral surface of the second intermediate material is positioned at the axially intermediate portion of the second intermediate material. In other words, the fracture surface can be prevented from being present near the opening end portion of the inner peripheral surface of the second intermediate material. Therefore, the fracture surface can be crushed by the mandrel in the process of expanding the diameter of the third intermediate material by rolling to form the fourth intermediate material. That is, the portion where the fracture surface exists can be made a smooth surface by applying a force in the compression direction. And when the diameter of the said 3rd intermediate material expands, it can prevent that a micro crack generate | occur | produces from the groove bottom part of the said torn surface, and can aim at the improvement of a yield.

Further, as in the invention described in claim 2, if the punching process for using the second intermediate material as the third intermediate material is performed in a compressed state, the area of the fracture surface (axial direction) Width dimension) can be kept small. And generation | occurrence | production of the said micro crack starting from this torn surface can be suppressed more fully.
In this case, if it is processed by swing forging as in the invention described in claim 3, it is possible to perform the process with a low load, and it is possible to secure the surface accuracy of a necessary portion at a low cost.
In addition, as described in claim 4, if the processing using the material as the first intermediate material is performed by swing forging, the equipment cost can be kept low even if a press machine with a small processing load is used. The shape accuracy of the intermediate material can be improved, which is advantageous for reducing the cost of the metal ring-shaped part.

Further, according to the metal part plastic working apparatus of the present invention as described above, the same press machine is used to process metal parts having different sizes and shapes, and intermediate materials corresponding to different processes. Yes. Moreover, by changing the setup for processing different types of metal parts and intermediate materials, by removing the metal part plastic processing device (die set) between the processing table and ram of the press machine, It can be done easily and quickly. For this reason, an increase in manufacturing cost can be suppressed for a large variety of small-quantity products.
In particular, if the electric motor is a servo motor as in the inventions described in claims 11 and 12, or the press machine is servo controlled as in the invention described in claim 12, the It can easily cope with low-volume production and can perform highly reliable processing.

Sectional drawing of the raw material thru | or 4th intermediate raw material which shows one example of embodiment of this invention in order of a process. Sectional drawing which shows the implementation state of the rocking forge which uses a raw material as a 1st intermediate material in the state immediately after a process start and immediately before a process end. The front view which shows the die set used for rocking forge in the state (A) before a process start, and the state (B) in the middle of a process. Sectional drawing which shows an example of the unpreferable processing method for making a raw material into a 1st intermediate material. Sectional drawing which shows the implementation state of the rocking forge which uses a 1st intermediate material as a 2nd intermediate material in the state immediately after a process start and immediately before a process end. Sectional drawing which shows an example of the unpreferable processing method for making a 1st intermediate material into a 2nd intermediate material. Sectional drawing which shows the implementation state of the punching process which uses a 2nd intermediate material as a 3rd intermediate material in order of a process. Sectional drawing which shows typically the state by which the center part of a 2nd intermediate material is pierce | punched with stamping. The schematic diagram for demonstrating the property of the internal peripheral surface of the obtained 3rd intermediate material. The front view (A) and side view (B) which show the die set used for a cold rolling process in the state before a process start. The front view (A) and side view (B) which are also shown in the middle of processing. The front view (A) and side view (B) which show in the state which takes out a 4th intermediate raw material similarly after completion | finish of a process. Sectional drawing of the raw material thru | or 4th intermediate material which shows the manufacturing method of metal ring-shaped components considered previously in order of a process. Sectional drawing which shows typically the state by which the center part of a 1st intermediate | middle material is pierce | punched with stamping. The schematic diagram for demonstrating the property of the internal peripheral surface of the obtained 2nd intermediate material. The schematic diagram of (A) which expands and shows the internal peripheral surface of a 2nd intermediate material simply, and (B) shown in the state which a crack generate | occur | produces with a rolling process. The schematic perspective view which shows the implementation condition of a cold rolling process.

[Example of Embodiment]
1 to 12, an example of an embodiment of each invention will be described. In this example, the material 18 as shown in FIG. 1A is replaced with a first intermediate material 19 as shown in FIG. 1B, a second intermediate material 20 as shown in FIG. 1C, and (D). After passing through the third intermediate material 21 as shown in (4), the fourth intermediate material 22 as shown in (E) is given, and the fourth intermediate material 22 is subjected to a predetermined finishing process to form a metal such as a bearing ring for radial bearings. A ring-shaped part made of steel. In addition, all processes until the material 18 is made the fourth intermediate material are performed by cold working. Of these materials 18 to fourth intermediate material 22 in this example, the material 18 and the first intermediate material 19 are the material 1 and the first intermediate material in the manufacturing method considered above shown in FIG. Corresponds to 2. Further, the third intermediate material 21 and the fourth intermediate material 22 in this example correspond to the second intermediate material 3 and the third intermediate material 4 in the manufacturing method considered above, respectively. In the case of this example, by making the second intermediate material 20 that is not made by the manufacturing method considered above and devising the processing direction and processing method for the second intermediate material 20, for example, the outer diameter in the completed state is Even when a product having a large diameter exceeding 200 mm is manufactured, the fracture surface is not present in the portion near the opening end of the inner peripheral surface of the second intermediate material 20. Hereinafter, this example will be described in the order of processing steps.

First, a long round bar is cut into a desired length by an appropriate method such as press, saw cutting, laser cutting, etc. to obtain a material (billet) 18 shown in FIG.
Next, this material 18 is upset to obtain a first intermediate material 19 shown in FIG. This upsetting process is performed by swing forging. The reason why swing forging is used instead of general upset forging is that the outer diameter is accurately finished with a low forming load, and the roundness of the outer peripheral surface and the parallelism and perpendicularity of both axial end surfaces are good. This is to obtain a disk shape.

  In the rocking forging, as shown in FIG. 2, first, the material 18 is supplied to the upper surface of the central portion of the die unit 23. In this die unit 23, a floating die 25 is installed above a fixed plate 24 so as to be moved up and down by springs 26 and 26. Further, the anchor block 27 placed at the center of the upper surface of the fixed plate 24 can be displaced relative to the center hole 29 of the floating plate 28 constituting the floating die 25 in the vertical direction (axial direction), and the gap It has been fitted. Further, an annular peripheral wall block 30 that also constitutes the floating die 25 is fixed concentrically with the center hole 29 at a portion near the outer diameter of the upper surface of the floating plate 28. The inner diameter of the peripheral wall block 30 is sufficiently larger than the inner diameter of the center hole 29 and is equal to the outer diameter of the first intermediate material 19 to be obtained. The thickness of the anchor block 27 and the thickness of the floating plate 28 are equal to each other. Therefore, in a state where the floating die 25 has been lowered against the elasticity of the springs 26, 26, the upper surface of the floating plate 28 and the upper surface of the anchor block 27 constituting the floating die 25 are on the same horizontal plane. Located on the top.

At the start of the swing forging, the material 18 is supplied with the floating die 25 fully raised, and the lower end of the material 18 is not rattled to the upper end of the center hole 29 of the floating plate 28. Fits inside. In this state, the material 18 is held at a predetermined position in the die unit 23. Next, the roll 31 that has been stopped above the die unit 23 is pressed downward while revolving around the central axis X _{18 of the} material 18 while rotating around the central axis X _{31 of} the roll 31. The roll 31 has the central axis X ₃₁ inclined with respect to the central axis X ₁₈ of the material 18 to the first intermediate material 19. Further, the processed surface 32 has a conical convex shape. The crossing angle between the central axes X ₁₈ and X ₃₁ is made to coincide with the inclination angle of the processing surface 32 with respect to a virtual plane orthogonal to the central axis X ₃₁ . Therefore, the direction of the portion of the processing surface 32 that contacts the material 18 to the first intermediate material 19 is perpendicular to the central axis X ₁₈ of the material 18 to the first intermediate material 19.

  The roll 31 as described above is lowered while rotating and revolving while pressing the material 18 to the first intermediate material 19. 2A, when the processed surface 32 is pressed against the axial end surface (upper end surface) of the material 18, the material 18 is crushed in the axial direction, and the diameter of the material 18 is increased. Gradually grows. In this initial stage of increasing the diameter of the material 18, the lower outer peripheral surface of the material 18 presses the upper surface of the floating plate 28, and the floating die 25 including the floating plate 28 is connected to the springs 26, It pushes down against the elasticity of 26. Since the elasticity of each of the springs 26 and 26 is weak, the lower surface of the floating plate 28 abuts on the upper surface of the fixed plate 24 in the initial stage, and the floating die 25 is not displaced further downward.

  The lowering of the roll 31 continues even after the lower surface of the floating plate 28 and the upper surface of the fixed plate 24 are in contact with each other, so that the axial dimension of the material 18 is further reduced, and its diameter The first intermediate material 19 is formed in a disk shape by expanding until it abuts against the inner peripheral surface of 30. In this process, as shown in FIG. 2B, the roll 31 constrains the outer periphery with the inner peripheral surface of the peripheral wall block 30, and stably performs not only the rotation but also the revolution. As a result, the shape of the processed surface 32 can be accurately transferred to the first intermediate material 19. After processing the material 18 into the first intermediate material 19 in this manner, the knockout pin 33 provided at the center of the fixing plate 24 is raised and the first intermediate material 19 is interposed via the anchor block 27. Is raised in the peripheral wall block 30, and the first intermediate material 19 is taken out from the peripheral wall block 30. The taken out first intermediate material 19 is sent to the next step.

  The reason why the processing (upsetting) of the material 18 to the first intermediate material 19 is performed not by general upsetting forging but by the above-described rocking forging as described above is that the shape is formed with a low molding load. This is because the accuracy can be improved. If the outer diameter of the work piece (the material 18 to the intermediate material 19) is constrained by general upsetting forging, not only the forming load is increased, but also a completely hermetically constrained restraint as shown in FIG. There is a possibility that the die 35 is destroyed as the position 34 is lowered. Further, even if the workpiece does not break, the workpiece cannot be sufficiently pressed, and a space is left between the die 35 and the workpiece. It becomes difficult to secure. On the other hand, when the material 18 is processed into the first intermediate material 19 by swing forging as in the present example, the entire upper end surface is limited even if the outer diameter of the workpiece is constrained. Since they are not constrained at the same time, they are not completely sealed until the final stage of processing, and the workpiece can be processed without causing a lack of thickness even in a small facility with a small processing load. For this reason, the outer diameter of the first intermediate material 19 can be accurately formed. Furthermore, in the case of this example, since the processing surface 32 of the roll 31 is a conical convex surface as described above, the shape accuracy of the outer surface (surface) of the first intermediate material 19 is not limited to the outer diameter surface. The axial end face can be sufficiently improved.

  The swing forging as described above can also be performed by a dedicated swing forging device as described in Patent Documents 1 to 3. However, the dedicated swing forging devices described in each of these patent documents are suitable for processing a small variety of mass-produced products, but are not suitable for processing a large variety of low-volume products. This example is intended for the processing of high-mix low-volume products such as the races that make up large-diameter radial rolling bearings, so the unit for swing forging (core element) that makes up the swing forging device Is incorporated into a die set as shown in FIG.

In the die set for swing forging, the die unit 23 is installed on the upper surface of the lower plate 36 that is positioned and supported on the upper surface of the processing table of the press machine, and the upper plate 37 installed above the lower plate 36. In addition to the roll 31, a head 38, a spindle unit 39, a reduction gear unit 40, and a drive motor 41 are installed below the roll 31. The die unit 23 can be easily replaced with various types prepared according to the shape and size of the workpiece (the material 18 to the first intermediate material 19). The head 38 is supported on the lower end portion of the rotating shaft constituting the spindle unit 39 coaxially with the rotating shaft, and the shape and size of the workpiece, the central axis X ₃₁ ( Various types prepared according to the inclination angle of FIG. 2) can be easily replaced. The type of the press machine is not particularly limited. Various general-purpose press machines (mechanical press and hydraulic press can be used) can be used. However, in the case of this example, the ram stroke speed (for example, constant speed) can be easily set as the press machine, and the roll 31 is rotated once (revolved) in combination with the drive motor 41 described below. It uses a servo press that can precisely control the amount of crushing during the process. The point that a servo press is used as the press working machine is the same in the swing forging and rolling processes described later.

  The fixed housing constituting the spindle unit 39 is supported and fixed to the lower surface of the upper plate 37. The rotary shaft rotatably supports the upper end portion or the intermediate portion thereof on the fixed housing, and supports and fixes the head 38 on the tip end portion (lower end portion). Further, a reduction large gear serving as an output portion of the reduction gear unit 40 is fixed to a portion near the lower end of the intermediate portion of the rotation shaft, and a reduction small gear serving as an input portion of the reduction gear unit 40 is connected to the drive motor 41. It is fixed to the output shaft. With this configuration, the head 38 can be driven to rotate at a low speed and with a large torque by the drive motor 41. The roll 31 is rotatably supported on the head 38 with a predetermined inclination angle as described above. With the above configuration, the roll 31 can be revolved around the central axis of the spindle unit 39 by the drive motor 41. The rotation of the roll 31 is automatically performed by revolving the roll 31 while pressing the processing surface 32 of the roll 31 against the upper end surface of the workpiece. The downward pressing of the roll 31 is performed by lowering the ram of the press machine.

  As described above, in the case of this example, the die unit 23, the roll 31, and the core elements necessary for swing forging are provided between the upper surface of the lower plate 36 and the lower surface of the upper plate 37. A head 38, the spindle unit 39, the speed reducer unit 40, and the drive motor 41 are installed to form a die set. For this reason, it is possible to easily change the setup for processing different types of workpieces with little or no production interruption. For example, during production of a metal ring-shaped part of a certain model number, the assembly of core elements relating to a separately prepared die set is completed in another place in advance, and after the production of the certain model number is completed, If the die set used for production is taken out of the press machine and the separately prepared die set is attached to the press machine, production can be resumed immediately. The taken-out die set is assembled with core elements for another model number to be produced next in another place until the next setup change. By adopting such a setup change and production flow, it is possible to produce many types of model numbers with almost no production interruption.

  As a specific procedure for attaching the die set to the press machine in a short time, first, slide the die set on the table of the press machine and position the die set using a predetermined positioning means such as a positioning pin. To do. Next, the lower plate of the die set is bolted to the table of the press machine, and the upper plate is bolted to the ram, and production is started using the die set. In the case of this example, the die set includes guide posts 42 and 42 and guide pushes 43 and 43 for preventing rolling during processing. The core elements can be easily assembled and the core elements can be easily assembled, and the setup of the die set can be easily changed. Therefore, depending on the model number, it may be necessary to change the core elements in various ways, and in some cases, it may be necessary to assemble the core elements and parts with a very complicated configuration. It is possible to produce a variety of products in small quantities with almost no production interruption.

  A servo motor is preferably used as the drive motor 41. The first reason for this is to accurately regulate the swing rotation speed. That is, in rocking forging, the amount of reduction per rotation affects the deformation of the workpiece. The amount of reduction is related to the stroke (the amount by which the ram is lowered) and the swing rotational speed, and a servo motor is used to control (properly regulate) the swing rotational speed. The second reason is that since the roll 31 generates heat during forming by swing forging, it is necessary to release heat from the work piece even during forming, and the swing rotational speed is set to a low rotational speed (10 Hz or less). Therefore, use a servo motor that stabilizes the torque even at low speeds. The third reason is that since the installation space is limited because it is necessary to incorporate it into the die set, a small servo motor that can obtain the required torque is used.

  In addition, the processing load of the swing forging can be suppressed to be lower than that of the general cold upset forging {for example, 29.4MN (3000 tonf)]. However, if the metal ring-shaped part having an outer diameter of about 200 to 400 mm is to be produced if it is about 980 kN (100 tonf), the processing using the material 18 as the first intermediate material 19 is also performed in this way. The processing of using the first intermediate material 19 as the second intermediate material 20 can be performed without any problem, except that the components 23, 31, 38, 39, 40, and 41 are formed on the upper surface of the lower plate 36 and the upper plate 37. In order to incorporate the die set between the lower surface and the die set, it is necessary to secure a gap between the plates 36 and 37 (the overall height of the die set increases). And the interval In order to ensure it, a press machine with a capacity of about 1470-5880 kN (150-600 tonf) is used.

  Further, during the rocking forging process, the die unit 23 and the roll 31 are not horizontally shaken (does not roll), the core (center axis) is stable, parallelism, perpendicularity, etc. In order to stabilize the accuracy, the guide posts 42, 42 planted vertically upward from the upper four corners of the lower plate 36 and the guide bushes suspended vertically downward from the lower four corners of the upper plate 37 43 and 43 are engaged with each other so as not to rattle at least during the progress of the swing forging, and freely in relative displacement in the vertical direction. With this configuration, the die unit 23 and the roll 31 are prevented from shaking in the horizontal direction and the core is stabilized regardless of the swing forging which is forming while generating an uneven load. The first intermediate material 19 can be processed accurately without applying excessive force to the die unit 23 and the roll 31. The guide posts 42 and 42 and the guide bushes 43 and 43 have a function that centering can be easily performed and core elements can be easily assembled as described above.

  In order to process the material 18 into the first intermediate material 19 with the die set having the above-described configuration, the material 18 is set in the die set 23 as shown in FIG. Thereafter, while rotating the roll 31 by the drive motor 41, the upper plate 37 provided with the roll 31 is pressed downward to control the crushing amount per revolution as shown in FIG. Lower to the state shown. In this process, the material 18 is processed into the first intermediate material 19 as described with reference to FIG.

  When the material 18 is processed into the first intermediate material 19 as described above, the first intermediate material 19 is then processed into the second intermediate material 20 by backward extrusion. In the case of this example, since it is intended to produce a variety of products in small quantities, if the required number of the first intermediate material 19 is processed, it is mounted on the press machine for processing the first intermediate material 19. The above die set is removed from the press machine. Thereafter, another die set for processing the first intermediate material 19 into the second intermediate material 20 is mounted on the same press machine. As shown in FIG. 5 described below, this another die set has a die unit 23a and a roll 31a in which the structure or shape of the die unit 23a is a die set 23 for processing the material 18 into the first intermediate material 19. Although it is different from the roll 31 (see FIG. 2), it basically has a similar structure. Below, the structure of said another die set and the process of processing said 1st intermediate material 19 into said 2nd intermediate material 20 by this another die set are demonstrated. When only a small number (for example, one) of press machines can be used, a plurality of processes are performed with one press machine as described above. On the other hand, if more press machines can be used, a press machine may be prepared for each process to constitute a production line. If the production line is configured, the productivity of the same model number can be increased, which is advantageous when mass-producing a specific model number. Further, when a large number of press machines can be used, the press machine is produced by changing the configuration of the press machine according to the number of ring-shaped parts to be manufactured.

  The die unit 23a is obtained by directly fixing the peripheral wall block 30a on the upper surface of the fixed plate 24a, and is not provided with the floating plate 28 and the springs 26 and 26 (see FIG. 2). The roll 31a has a two-step structure in which the processed surface 32a has a stepped surface 44 at a radially intermediate portion, and a central portion and a portion closer to the outer diameter are inclined by the same angle in the same direction. Although the inclination direction and inclination angle of each part and the inclination angle of the roll 31a as a whole are the same as those of the roll 31 shown in FIG. 2, they are not necessarily the same. The outer diameter of the stepped surface 44 is made smaller toward the base end of the roll 31a. Then, in a state where the entire roll 31a is inclined and incorporated in the die set, the direction of the portion of the step surface 44 where the first intermediate material 19 to the second intermediate material 20 are processed is between these two intermediate surfaces. The materials 19 and 20 are oriented in the direction of the central axis.

  In order to process the first intermediate material 19 into the second intermediate material 20, first, as shown in FIG. 5A, the first intermediate material 19 is fitted into the peripheral wall block 30a. The inner diameter of the peripheral wall block 30a is slightly larger than the outer diameter of the first intermediate material 19 (by a value as small as possible so that the inner fitting work can be easily performed). Therefore, the first intermediate material 19 is placed at a predetermined position on the upper surface of the fixing plate 24a with the first intermediate material 19 fitted in the peripheral wall block 30a. Therefore, the roll 31 a is pressed downward while rotating, and the center portion of the processed surface 32 a of the roll 31 a is pressed against the center portion of the upper surface of the first intermediate material 19. As a result, as shown in FIG. 5B, the central portion of the first intermediate material 19 is recessed in a circular shape, and a portion near the outer diameter of the first intermediate material 19 enters the peripheral portion of the step surface 44. The rear extrusion process is performed. At the same time, the outer peripheral surface of the first intermediate material 19 is strongly pressed against the inner peripheral surface of the peripheral wall block 30a. Then, at the stage where the central portion is recessed to some extent, the outer diameter side portion hits the outer diameter portion of the processed surface 32a and is smoothed at the outer diameter portion, and the second intermediate material 20 is smoothed. The molding work is completed.

  If the roll 31a continues to rotate near the bottom dead center for an excessively long time after this forming operation is completed, there is a possibility that burrs may occur on the outer peripheral edge of the obtained second intermediate material 20. Therefore, in order to omit the trouble of removing this burr, the roll 31a is rotated for an appropriate molding time (roll rotation speed) near the bottom dead center in consideration of the variation in the volume of the material 18. Then, the processing operation of the second intermediate material 20 is finished. The disk-shaped second intermediate material 20 having the circular recess 45 at the center of the upper surface thus obtained is pushed out of the peripheral wall block 30a by the knockout pin 33a and taken out from the die unit 23a. Sent to the process.

  As described above, when the first intermediate material 19 is processed by backward extrusion, the shape accuracy of the second intermediate material 20 obtained, that is, the shape of the circular recess 45, the shape of the outer peripheral surface, and the shapes of both end surfaces in the axial direction are obtained. In addition, the perpendicularity and the coaxiality between the circular recess 45 and the outer peripheral surface can be improved. In addition, as for the above-described rear extrusion process, if the general forging process as shown in FIG. 6 is performed, not only the molding load becomes too high, but also as in the case described in FIG. Thus, there is a possibility that the die 35a is broken as the punch 34a is lowered, and it is difficult to ensure the shape accuracy of the workpiece due to the lack of thickness. On the other hand, in the case of this example, since the sealing is not completely closed until the processing is completed, the surface of the first intermediate material 19 or the second intermediate material 20 is a die including the roll 31a and the peripheral wall block 30a. It is possible to ensure the shape accuracy of the workpiece without hitting the unit 23a with a gap that causes a lack of thickness. By processing the first intermediate material 19 into the second intermediate material 20, the fracture surface can be reduced, defects due to microcracks can be eliminated, and the yield of the material can be improved.

  In the above-described backward extrusion process and upsetting process in the preceding process, it is preferable to control the crushing amount per revolution by servo-controlling both the revolution number of the tool and the stroke speed. . Therefore, a servo press is usually used as a press machine used for the above quantity processing. However, only one of the revolution number and stroke speed of the tool may be servo controlled. That is, for example, the stroke speed of the ram of the mechanical press can be detected by a sensor, and the rotation speed can be controlled by a servo motor in accordance with the stroke speed to control the crushing amount per revolution.

  The second intermediate material 20 obtained as described above is placed between the processing table and the ram of the press machine after the vertical direction is reversed after taking out from the die unit 23a. Set on a die set as shown in 7. Then, with this die set, a portion corresponding to the bottom of the circular recess 45 is punched out to form an annular third intermediate material 21. The die set used for this punching process is for holding down the die unit 23b for holding the second intermediate material 20, the counter punch 46 and punch 47 for punching the portion, and the second intermediate material 20. Of the floating punch 48.

  The die unit 23b is formed by fixing a peripheral wall block 30b for fitting (press-fitting) the second intermediate material 20 on the upper surface of the fixing plate 28a for placing the second intermediate material 20 thereon. . The counter punch 46 is inserted through the center hole 49 of the fixed plate 28a so as to be movable up and down, and has an outer diameter dimension that can be fitted (lightly press-fitted) into the circular recess 45 without a gap. The punch 47 is disposed above the counter punch 46 and concentric with the counter punch 46, and is pressed downward by the ram. Further, the floating punch 48 is externally fitted around the punch 47 so as to be movable up and down with respect to the punch 47, and is given downward elasticity by a lower pressure means 50 such as a spring.

  In order to punch out the portion corresponding to the bottom of the circular recess 45 in the second intermediate material 20 using the die set as described above, first, as shown in FIG. The second intermediate material 20 is fitted (press-fitted) into the upper end portion of the peripheral wall block 30b with the circular recess 45 down, and the upper end portion of the counter punch 46 is fitted (lightly press-fitted) into the circular recess 45. From this state, as shown in FIG. 7B, the punch 47 and the floating punch 48 are lowered, and the front end surface (lower end surface) of the punch 47 is pushed into the center of the upper surface of the second intermediate material 20. At the same time, the lower surface of the floating punch 48 suppresses the portion of the second intermediate material 20 that is closer to the outer diameter of the upper surface. In this state, the second intermediate material 20 is in a so-called hydrostatic pressure state in which the entire surface is suppressed. Therefore, the punch 47 is further lowered to punch out a portion of the second intermediate material 20 corresponding to the bottom of the circular recess 45 as shown in FIG. And In this example, since the shape accuracy of the second intermediate material 20 is good, the fixing plate 28a, the peripheral wall block 30b, the counter punch 46, the punch 47, and the floating punch 48 With the second intermediate material 20 covered, the gap between the surface of the second intermediate material 20 and the mating surface can be made substantially zero. For this reason, the hydrostatic pressure state can be sufficiently realized.

  With the punching process {in the process of (B) → (C) in FIG. 7, (A) → (B) → (C) in FIG. 8]} in the radial intermediate portion of the second intermediate material 20, A force in the shearing direction is applied between the inner peripheral edge of the upper end opening of the center hole 49 of the fixing plate 28a constituting the die unit 23b and the outer peripheral edge of the front end surface of the punch 47. By this force, as shown in FIG. 8B, cracks 7a and 7b are generated (run) toward the central portion in the thickness direction of the second intermediate material 20. At the moment when the tips of both cracks 7a and 7b are continuous, the central portion of the second intermediate material 20 is separated from the outer diameter portion, and the central portion is discharged as scrap 8a. Is the third intermediate material 21.

  On the inner peripheral surface of the third intermediate material 21, as shown in FIG. 9, the sag 9a, the shearing surface 10a, the fracture surface 11a, and the circular recess are sequentially formed from the upper side which is the pushing side of the punch 47. There is a smooth surface 52 formed by rocking forging, which is the inner peripheral surface of 45. In the case of this example, when the circular recess 45 is provided on the side opposite to the pushing direction of the punch 47, the fracture surface 11a is formed in the axially intermediate portion when viewed as the third intermediate material 21 as a whole. It exists. Further, by punching the central portion of the second intermediate material 20 under a hydrostatic pressure state, the width dimension of the shearing surface 10a is increased compared to the case where it is not performed under a hydrostatic pressure state. The width dimension of the fracture surface 11a can be made narrower. In this way, by narrowing the width of the fracture surface 11a and positioning the fracture surface 11a in the middle portion in the axial direction, the fracture surface 11a of the third intermediate material 21 is crushed during the cold rolling process described below, and a minute Even if the concavities and convexities that lead to the occurrence of cracks are crushed (smoothed) and subjected to significant diameter expansion, the occurrence of crack damage can be prevented.

  Although it is possible to completely eliminate the fracture surface 11a, in that case, the floating punch 48 is moved downward by a very large force in the process of (B) → (C) in FIG. It is necessary to press. For this purpose, it is necessary to install a hydraulic device for generating such a large force in the punching device, which complicates the device and increases the cost. In order to prevent the occurrence of minute cracks during the rolling process described below, as long as the fracture surface 11a is positioned at the intermediate portion in the axial direction of the third intermediate material 21, some fracture surface 11a remains. There is no problem. Therefore, in the case of this example, a simple structure such as a spring or a gas cushion that can be configured in a small size is adopted for the lower pressure means 50.

  In this example, in order to make the width of the fracture surface 11a narrower, the clearance between the punch 47 and the center hole 49 {("inner diameter of the center hole 49"-"outer diameter of the punch 47"). / 2} is made smaller than in the case of normal punching. Specifically, the clearance is set to about 1 to 10% of the thickness of the center portion (circular recess 45 portion) of the second intermediate material 20. Further, the allowance for press-fitting the upper end of the counter punch 46 into the circular recess 45 is about 0.1 to 0.5% of the outer diameter of the second intermediate material 20. Note that the nominal value of the press-fitting allowance (target press-fitting allowance) is appropriately determined by trial production or the like performed before actual production. Further, the load required for the punching process may be lower than the load for normal forging such as upsetting forging and backward extrusion, and can be determined in the same manner as in the normal pressing.

  The third intermediate material 21 made as described above is disposed at a plurality of intervals (for example, at equal intervals in the circumferential direction) after raising the punch 47 and the floating punch 48 by raising the ram. The other three) knockout pins 51, 51 are pushed out from the inner diameter side of the peripheral wall block 30b and sent to the next step.

  The third intermediate material 21 is subjected to a cold rolling process to be expanded in diameter to form a fourth intermediate material 22 having a larger diameter than the third intermediate material 21 as shown in FIG. The fourth intermediate material 22 is generally formed with a raceway groove or the like thereafter by a lathe process, but the raceway process can be omitted by forming the raceway groove by the cold rolling process. . In any case, if the metal ring-shaped part is a bearing ring for a radial rolling bearing, after forming the raceway groove, finish processing such as heat treatment and grinding is performed, and the raceway for the radial rolling bearing. Completed as a circle.

  Such cold rolling processing can also be performed by a dedicated rolling processing device as described in Patent Documents 4 to 6. However, the dedicated rolling processing apparatuses described in each of these patent documents are also suitable for processing a small variety of mass-produced products, but are not suitable for processing a large variety of small-volume products. In addition, when making a large-diameter metal ring-shaped part, a large dedicated device is required. Therefore, in the case of this example, even in the cold rolling process as described above, a die set as shown in FIGS. 10 to 12 is installed between the processing table of the press machine and the ram. This die set is arranged so as to be rotatable about a horizontal axis, and also includes a mandrel 15a, a pair of first support rolls 53, 53, a pair of second support rolls 54, 54, A forming roll 16a, a reduction gear unit 55, and a drive motor 56 are provided. Among these, the mandrel 15a, the pair of first support rolls 53, 53, and the pair of second support rolls 54, 54 are located above the lower plate 57 supported on the upper surface of the processing table of the press machine. Is provided. Further, the mandrel 15a can be displaced in the axial direction as indicated by an arrow in FIG. 12A, and the third intermediate material 21 through the third material 21 to be processed around the mandrel 15a. The four intermediate materials 22 can be attached and detached. The axial movement of the mandrel 15a is performed by a direct acting actuator 61 such as a hydraulic cylinder or an air cylinder. On the other hand, the forming roll 16a, the speed reducer unit 55, and the drive motor 56 are provided below an upper plate 58 supported on the lower surface of the ram of the press machine.

  The two positions in the axial direction of the mandrel 15a are the outer peripheries of the upper ends of the first support rolls 53, 53 provided apart from each other in the left-right direction in FIGS. It is in contact with the surface. Further, the outer peripheral surfaces of the lower end portions of the first support rolls 53, 53 are both separated from each other in the front and back directions of FIGS. It is made to contact | abut to the outer peripheral surface of the upper end part of 54,54. Further, these support rolls 53 and 54 are rotatably supported by a lower support frame 59 provided on the upper surface of the lower plate 57. With this configuration, the mandrel 15a is allowed to rotate while supporting a radial load applied to the mandrel 15a during the cold rolling process. Therefore, the rotation center axis of the mandrel 15a and the rotation center axes of the support rolls 53 and 54 are parallel to each other.

  The first support rolls 53 and 53 are supported on the lower support frame 59 by cantilevered support shafts. Therefore, there is no support shaft between the first support rolls 53, 53, and even if the fourth intermediate material 22 having a large diameter is processed as shown in FIG. The four intermediate materials 22 do not interfere with each other. However, the second support rolls 54 and 54 that finally support the processing load are supported by the lower support frame 59 in a double-supported manner to ensure load bearing performance.

  The forming roll 16a is rotatably supported on an upper support frame 60 fixed to the lower surface of the upper plate 58. The forming roll 16 a can be driven to rotate by the drive motor 56 via the speed reducer unit 55. Further, the forming roll 16a is supported on the upper support frame 60 by a sufficiently thick support shaft so as to be able to support a large processing load. Therefore, no support roll is provided on the upper support frame 60 side. Regarding the drive motor 56, a servo motor is preferably used for the same reason as that of the above-described swing forging die set.

  In order to process the third intermediate material 21 into the fourth intermediate material 22 using the cold rolling die set as described above, first, as shown in FIG. The third intermediate material 21 is loosely fitted. In this operation, the mandrel 15a is retracted to the left in FIG. 10A, the third intermediate material 21 is brought into a predetermined position, and then the mandrel 15a is moved to the right in FIG. By moving forward. The third intermediate material 21 is brought in by a robot arm or by a worker's hand. In the state where the third intermediate material 21 is set in this way, the lower half portion of the third intermediate material 21 is disposed between the upper ends of the first support rolls 53, 53. Further, the molding roll 16 a is positioned immediately above the third intermediate material 21.

  From this state, the ram of the press machine is lowered while the forming roll 16a is rotationally driven by the drive motor 56 via the reduction gear unit 55. Then, the molding roll 16 a is pressed downward through the upper plate 58, and the outer peripheral surface of the lower end portion of the molding roll 16 a is strongly pressed against the outer peripheral surface of the upper end portion of the third intermediate material 21. As a result, the third intermediate material 21 is strongly pressed between the outer peripheral surface of the mandrel 15a and the outer peripheral surface of the molding roll 16a, from the state shown in FIG. 10 to the state shown in FIG. The diameter gradually expands to become a fourth intermediate material 22 as shown in FIG. In this way, in the process of using the third intermediate material 21 as the fourth intermediate material 22, no cracks are generated at the fracture surface 11 a existing in the axially intermediate portion of the inner peripheral surface of the third intermediate material 21. The mandrel 15a is sufficiently crushed by the outer peripheral surface to become a smooth surface. That is, when the diameter of the third intermediate material 21 begins to expand, a groove portion that becomes a starting point of cracking as described with reference to FIG. 16 is formed on the inner peripheral surface of the third intermediate material 21. The fourth intermediate material 14 can be processed with a high yield. The fourth intermediate material 22 obtained in this way is retracted and removed from the mandrel 15a as shown in FIG. 12, and sent to the next finishing step. This take-out operation is also performed by a robot arm or by a worker's hand.

  In the rolling process, servo control is performed on both the rotational speed of the third intermediate material 21 to the fourth intermediate material 22 and the stroke speed of the forming roll 16a, which are ring-shaped materials. The crushing amount per rotation of the third intermediate material 21 to the fourth intermediate material 22 is preferably controlled. However, only one of the rotation speed of the third intermediate material 21 to the fourth intermediate material 22 and the stroke speed of the forming roll 16a may be servo controlled. For example, the stroke speed of the ram of the mechanical press may be detected by a sensor, and the rotation speed may be controlled by a servo motor in accordance with the stroke speed to control the crushing amount per rotation. Thus, the point that the stroke speed and the number of revolutions are important parameters for the control are the same as in the case of the control of the upsetting process and the backward extrusion process by the above-mentioned swing forging.

The material 18 used when implementing the present invention is mainly bearing steel or carburized steel, and lubrication for processing is performed by a bonder process. However, when the area of the cut surface (both end surfaces in the axial direction) of the material 18 is large, the process of using the material 18 as the first intermediate material 19 and the subsequent processes can be lubricated by oil application. .
In addition, the processing temperature is basically set to be cold throughout the entire process, but when the diameter of the metal ring-shaped part to be manufactured is particularly large, it can be formed warm (200 to 700 ° C.).
Also, in the press working machine used in the process of using the material 18 as the first intermediate material 19 and subsequent processes, the amount of reduction per rotation is important in each process, so that it can be adjusted according to the number of rotations of the roll. In order to control the descending speed of the press machine, it is preferable to use a servo press. However, the press machine can be used for any of a mechanical press, a hydraulic press, and a transfer press.

DESCRIPTION OF SYMBOLS 1 Material 2 1st intermediate material 3 2nd intermediate material 4 3rd intermediate material 5 Die 6 Punch 7a, 7b Crack 8, 8a Scrap 9, 9a Sag 10, 10a Shear surface 11, 11a Fracture surface 12, 12a Burr 13 Central hole 14 Cold rolling processing device 15, 15a Mandrel 16, 16a Forming roll 17 Crack 18 Material 19 First intermediate material 20 Second intermediate material 21 Third intermediate material 22 Fourth intermediate material 23, 23a, 23b Die unit 24, 24a fixed Plate 25 Floating die 26 Spring 27 Anchor block 28, 28a Floating plate 29 Center hole 30, 30a, 30b Circumferential wall block 31, 31a Roll 32, 32a Work surface 33, 33a Knockout pin 34, 34a Punch 35, 35a Die 36 Lower plate 37 Upper plate 38 Head 3 9 Spindle unit 40 Reducer unit 41 Drive motor 42 Guide post 43 Guide bush 44 Stepped surface 45 Circular recess 46 Counter punch 47 Punch 48 Floating punch 49 Center hole 50 Lower pressure means 51 Knockout pin 52 Smooth surface 53 First support roll 54 First Two support rolls 55 Reduction gear unit 56 Drive motor 57 Lower plate 58 Upper plate 59 Lower support frame 60 Upper support frame 61 Actuator

The present invention relates to an improvement of the production apparatus used directly in the practice of the method of manufacturing a metal ring-shaped components such as bearing rings for radial rolling bearing.

For example, in order to obtain a metal ring-shaped part such as a bearing ring (outer ring, inner ring) constituting a radial rolling bearing incorporated in a rotation support portion of various industrial machines such as a rolling mill at low cost, It is conceivable to manufacture by a manufacturing method as shown in FIG.
In this manufacturing method, first, a cylindrical material 1 as shown in FIG. 13A is obtained by cutting a long material into a predetermined length. Next, the material 1 is crushed in the axial direction to form a disc-shaped first intermediate material 2 as shown in FIG. Next, the central portion on one side of the first intermediate material 2 is punched and removed by pressing to obtain an annular second intermediate material 3 as shown in FIG. Next, the diameter of the second intermediate material 3 is expanded by rolling to obtain an annular third intermediate material 4 as shown in FIG. Furthermore, a metal to be produced such as a finish rolling process for forming the raceway surface, a heat treatment process for hardening the raceway surface, and a grinding process for improving the surface roughness of the raceway surface on the third intermediate material 4 A predetermined finishing process is performed depending on the ring-shaped part made of metal, so that the ring-shaped part made of metal such as the bearing ring is obtained.

  However, in the case of manufacturing a metal ring-shaped part having a large diameter (for example, an outer diameter of 200 mm or more) in the process as described above, the first intermediate material 2 shown in FIG. In the process of making the second intermediate material 3 shown in (C), there is a possibility that a minute crack may occur on the inner diameter side of the intermediate material and the intermediate material may have to be discarded as a defective product. It was found by the inventors' research. This point will be described with reference to FIGS.

  As shown in (B) → (C) of FIG. 13, the work of punching out the central portion of the first intermediate material 2 to form the second intermediate material 3 is performed as shown in FIGS. 14 (A) → (B) → (C). As shown in FIG. 5, the punch 6 is pressed against the central portion of the upper surface of the first intermediate material 2 while the lower intermediate diameter portion of the first intermediate material 2 is held by the die 5. In the process of this punching operation, as shown in FIGS. 14A to 14B, as the punch 6 is pushed, the outer peripheral edge of the punch 6 is abutted on the upper surface of the first intermediate material 2. Cracks 7a from the contacting portion and the portion of the lower surface of the first intermediate material 2 that is in contact with the inner peripheral edge of the die 5 toward the center in the thickness direction of the first intermediate material 2; 7b occurs (runs). Then, at the moment when the tips of both cracks 7a and 7b are continuous, the central portion of the first intermediate material 2 is separated from the portion near the outer diameter, and this central portion is discharged as scrap 8, and the portion closer to the outer diameter. Is the second intermediate material 3.

  On the inner peripheral surface of the center hole 13 of the second intermediate material 3 obtained in this way, as shown in FIG. 15, the sagging 9 and the shearing surface 10 are sequentially formed from the upper side that is the pushing side of the punch 6. Then, the fracture surface 11 and the burrs 12 exist. Of these, the fracture surface 11 is a surface formed by the cracks 7a and 7b shown in FIG. For this reason, the surface of the fracture surface 11 is a rough surface having a large surface roughness and a sawtooth shape in cross section as shown in FIG. When the annular second intermediate material 3 is formed by the method shown in FIGS. 13B to 13C and FIG. 14, the fracture surface 11 as described above becomes the center hole 13 of the second intermediate material 3. It will be in the state which exists in the part near opening edge part.

  In particular, when producing a large-diameter ring-shaped part having an outer diameter of 200 mm or more, for example, the second intermediate material 3 as described above is expanded by a cold rolling processing apparatus 14 as shown in FIG. When the diameter is increased, minute cracks 17 and 17 are likely to be generated from the broken surface 11 as shown in FIG. First, in the cold rolling process, the second intermediate material 3 is externally fitted to a mandrel 15 that is rotatably supported and constitutes the cold rolling apparatus 14, and the outer peripheral surface of the second intermediate material 3 is fitted. The pressing is performed by rotating the forming roll 16 while pressing the forming roll 16. When such a cold rolling process is performed, a portion of the fracture surface 11 near the opening end portion of the center hole 13 is not sufficiently pressed by the mandrel 15 and the fracture of this portion is not performed. The cross-section 11 is greatly expanded as the diameter of other portions is increased without being sufficiently crushed by the mandrel 15 (without being subjected to a load in the compression direction to be a smooth surface). As a result, as shown in FIG. 16B, a minute crack starting from the groove bottom portion of the fracture surface 11 from a portion near the opening end of the center hole 13 in a part of the fracture surface 11. 17 and 17 are considered to occur.

JP-A-1-317650 Japanese Patent Laid-Open No. 3-110038 JP-A-8-47741 Japanese Patent Laid-Open No. 10-5919 JP 2000-117379 A Japanese Patent No. 3692635

This invention is invented in order to implement | achieve the processing apparatus which can further reduce the manufacturing cost of metal ring-shaped components .

Each of the metal parts plastic working apparatuses of the present invention comprises a press machine and a die set that can be attached to and detached from the press machine.
Of these, the press working machine includes a working table and a ram.
The die set includes a lower plate, a holding portion, an upper plate, a processing tool, and an electric motor.
Lower plate of this is placed on the upper surface of the working table of the press machine.
The holding portion is for holding a workpiece and is provided on the upper surface of the lower plate.
The upper plate is installed on the lower surface of the ram of the press machine above the lower plate and pressed downward by the ram of the press machine.
Moreover, the said processing tool is provided in the lower surface of the said upper board, and presses the said to-be-processed object as this upper board falls.
Further, the electric motor is for rotationally driving the processing tool, and is supported and fixed to a part of the upper plate.

In particular, in the metal part plastic working apparatus according to the first aspect of the invention, the die set is a die set for swing forging. For this purpose, the holding portion, and the die having a peripheral shape among matching the outer peripheral surface shape of the machining completion of the workpiece, also the machining tool, the workpiece by oscillating the forging A roll for plastic deformation.
In contrast, in the metal part plastic working apparatus according to the second aspect of the present invention, the die set is a die set for roll processing. For this purpose, the holding part is a mandrel that is arranged in a horizontal direction and rotates in a state in which an annular work piece is loosely fitted, and the work tool presses the work piece against the mandrel. The forming roll is rotated while rolling to increase the diameter of the workpiece by rolling.
In the metal part plastic working apparatus according to the third aspect of the present invention, the swing forging die set and the rolling die set can be mounted and exchanged respectively.
In the case of carrying out the metal part plastic working apparatus of the present invention, preferably, the electric motor is a servo motor capable of adjusting the rotational speed, as in the invention described in claim 4 , or As in the invention described in claim 5 , a press machine having a ram for pressing the upper plate has a function of servo-controlling the stroke of the ram.

According to the plastic working apparatus for metal parts of the present invention as described above , the same press working machine can be used to machine metal parts having different dimensions and shapes and intermediate materials corresponding to different processes. In addition, the setup change for processing different kinds of metal parts and intermediate materials can be easily and quickly performed by detaching the die set between the processing table and the ram of the press machine. For this reason, an increase in manufacturing cost can be suppressed for a large variety of small-quantity products.
In particular, if the electric motor is a servo motor as in the invention described in claim 4 or if the press machine has a function of servo-controlling as in the invention described in claim 5 , a small variety of products It can easily handle production and perform highly reliable processing.

Sectional drawing of the raw material thru | or 4th intermediate raw material which shows one example of embodiment of this invention in order of a process. Sectional drawing which shows the implementation state of the rocking forge which uses a raw material as a 1st intermediate material in the state immediately after a process start and immediately before a process end. The front view which shows the die set used for rocking forge in the state (A) before a process start, and the state (B) in the middle of a process. Sectional drawing which shows an example of the unpreferable processing method for making a raw material into a 1st intermediate material. Sectional drawing which shows the implementation state of the rocking forge which uses a 1st intermediate material as a 2nd intermediate material in the state immediately after a process start and immediately before a process end. Sectional drawing which shows an example of the unpreferable processing method for making a 1st intermediate material into a 2nd intermediate material. Sectional drawing which shows the implementation state of the punching process which uses a 2nd intermediate material as a 3rd intermediate material in order of a process. Sectional drawing which shows typically the state by which the center part of a 2nd intermediate material is pierce | punched with stamping. The schematic diagram for demonstrating the property of the internal peripheral surface of the obtained 3rd intermediate material. The front view (A) and side view (B) which show the die set used for a cold rolling process in the state before a process start. The front view (A) and side view (B) which are also shown in the middle of processing. The front view (A) and side view (B) which show in the state which takes out a 4th intermediate raw material similarly after completion | finish of a process. Sectional drawing of the raw material thru | or 4th intermediate material which shows the manufacturing method of metal ring-shaped components considered previously in order of a process. Sectional drawing which shows typically the state by which the center part of a 1st intermediate | middle material is pierce | punched with stamping. The schematic diagram for demonstrating the property of the internal peripheral surface of the obtained 2nd intermediate material. The schematic diagram of (A) which expands and shows the internal peripheral surface of a 2nd intermediate material simply, and (B) shown in the state which a crack generate | occur | produces with a rolling process. The schematic perspective view which shows the implementation condition of a cold rolling process.

[Example of Embodiment]
1 to 12, an example of an embodiment of each invention will be described. In this example, the material 18 as shown in FIG. 1A is replaced with a first intermediate material 19 as shown in FIG. 1B, a second intermediate material 20 as shown in FIG. 1C, and (D). After passing through the third intermediate material 21 as shown in (4), the fourth intermediate material 22 as shown in (E) is given, and the fourth intermediate material 22 is subjected to a predetermined finishing process to form a metal such as a bearing ring for radial bearings. A ring-shaped part made of steel. In addition, all processes until the material 18 is made the fourth intermediate material are performed by cold working. Of these materials 18 to fourth intermediate material 22 in this example, the material 18 and the first intermediate material 19 are the material 1 and the first intermediate material in the manufacturing method considered above shown in FIG. Corresponds to 2. Further, the third intermediate material 21 and the fourth intermediate material 22 in this example correspond to the second intermediate material 3 and the third intermediate material 4 in the manufacturing method considered above, respectively. In the case of this example, by making the second intermediate material 20 that is not made by the manufacturing method considered above and devising the processing direction and processing method for the second intermediate material 20, for example, the outer diameter in the completed state is Even when a product having a large diameter exceeding 200 mm is manufactured, the fracture surface is not present in the portion near the opening end of the inner peripheral surface of the second intermediate material 20. Hereinafter, this example will be described in the order of processing steps.

First, a long round bar is cut into a desired length by an appropriate method such as press, saw cutting, laser cutting, etc. to obtain a material (billet) 18 shown in FIG.
Next, this material 18 is upset to obtain a first intermediate material 19 shown in FIG. This upsetting process is performed by swing forging. The reason why swing forging is used instead of general upset forging is that the outer diameter is accurately finished with a low forming load, and the roundness of the outer peripheral surface and the parallelism and perpendicularity of both axial end surfaces are good. This is to obtain a disk shape.

  In the rocking forging, as shown in FIG. 2, first, the material 18 is supplied to the upper surface of the central portion of the die unit 23. In this die unit 23, a floating die 25 is installed above a fixed plate 24 so as to be moved up and down by springs 26 and 26. Further, the anchor block 27 placed at the center of the upper surface of the fixed plate 24 can be displaced relative to the center hole 29 of the floating plate 28 constituting the floating die 25 in the vertical direction (axial direction), and the gap It has been fitted. Further, an annular peripheral wall block 30 that also constitutes the floating die 25 is fixed concentrically with the center hole 29 at a portion near the outer diameter of the upper surface of the floating plate 28. The inner diameter of the peripheral wall block 30 is sufficiently larger than the inner diameter of the center hole 29 and is equal to the outer diameter of the first intermediate material 19 to be obtained. The thickness of the anchor block 27 and the thickness of the floating plate 28 are equal to each other. Therefore, in a state where the floating die 25 has been lowered against the elasticity of the springs 26, 26, the upper surface of the floating plate 28 and the upper surface of the anchor block 27 constituting the floating die 25 are on the same horizontal plane. Located on the top.

At the start of the swing forging, the material 18 is supplied with the floating die 25 fully raised, and the lower end of the material 18 is not rattled to the upper end of the center hole 29 of the floating plate 28. Fits inside. In this state, the material 18 is held at a predetermined position in the die unit 23. Next, the roll 31 that has been stopped above the die unit 23 is pressed downward while revolving around the central axis X _{18 of the} material 18 while rotating around the central axis X _{31 of} the roll 31. The roll 31 has the central axis X ₃₁ inclined with respect to the central axis X ₁₈ of the material 18 to the first intermediate material 19. Further, the processed surface 32 has a conical convex shape. The crossing angle between the central axes X ₁₈ and X ₃₁ is made to coincide with the inclination angle of the processing surface 32 with respect to a virtual plane orthogonal to the central axis X ₃₁ . Therefore, the direction of the portion of the processing surface 32 that contacts the material 18 to the first intermediate material 19 is perpendicular to the central axis X ₁₈ of the material 18 to the first intermediate material 19.

  The roll 31 as described above is lowered while rotating and revolving while pressing the material 18 to the first intermediate material 19. 2A, when the processed surface 32 is pressed against the axial end surface (upper end surface) of the material 18, the material 18 is crushed in the axial direction, and the diameter of the material 18 is increased. Gradually grows. In this initial stage of increasing the diameter of the material 18, the lower outer peripheral surface of the material 18 presses the upper surface of the floating plate 28, and the floating die 25 including the floating plate 28 is connected to the springs 26, It pushes down against the elasticity of 26. Since the elasticity of each of the springs 26 and 26 is weak, the lower surface of the floating plate 28 abuts on the upper surface of the fixed plate 24 in the initial stage, and the floating die 25 is not displaced further downward.

  The lowering of the roll 31 continues even after the lower surface of the floating plate 28 and the upper surface of the fixed plate 24 are in contact with each other, so that the axial dimension of the material 18 is further reduced, and its diameter The first intermediate material 19 is formed in a disk shape by expanding until it abuts against the inner peripheral surface of 30. In this process, as shown in FIG. 2B, the roll 31 constrains the outer periphery with the inner peripheral surface of the peripheral wall block 30, and stably performs not only the rotation but also the revolution. As a result, the shape of the processed surface 32 can be accurately transferred to the first intermediate material 19. After processing the material 18 into the first intermediate material 19 in this manner, the knockout pin 33 provided at the center of the fixing plate 24 is raised and the first intermediate material 19 is interposed via the anchor block 27. Is raised in the peripheral wall block 30, and the first intermediate material 19 is taken out from the peripheral wall block 30. The taken out first intermediate material 19 is sent to the next step.

  The reason why the processing (upsetting) of the material 18 to the first intermediate material 19 is performed not by general upsetting forging but by the above-described rocking forging as described above is that the shape is formed with a low molding load. This is because the accuracy can be improved. If the outer diameter of the work piece (the material 18 to the intermediate material 19) is constrained by general upsetting forging, not only the forming load is increased, but also a completely hermetically constrained restraint as shown in FIG. There is a possibility that the die 35 is destroyed as the position 34 is lowered. Further, even if the workpiece does not break, the workpiece cannot be sufficiently pressed, and a space is left between the die 35 and the workpiece. It becomes difficult to secure. On the other hand, when the material 18 is processed into the first intermediate material 19 by swing forging as in the present example, the entire upper end surface is limited even if the outer diameter of the workpiece is constrained. Since they are not constrained at the same time, they are not completely sealed until the final stage of processing, and the workpiece can be processed without causing a lack of thickness even in a small facility with a small processing load. For this reason, the outer diameter of the first intermediate material 19 can be accurately formed. Furthermore, in the case of this example, since the processing surface 32 of the roll 31 is a conical convex surface as described above, the shape accuracy of the outer surface (surface) of the first intermediate material 19 is not limited to the outer diameter surface. The axial end face can be sufficiently improved.

  The swing forging as described above can also be performed by a dedicated swing forging device as described in Patent Documents 1 to 3. However, the dedicated swing forging devices described in each of these patent documents are suitable for processing a small variety of mass-produced products, but are not suitable for processing a large variety of low-volume products. This example is intended for the processing of high-mix low-volume products such as the races that make up large-diameter radial rolling bearings, so the unit for swing forging (core element) that makes up the swing forging device Is incorporated into a die set as shown in FIG.

In the die set for swing forging, the die unit 23 is installed on the upper surface of the lower plate 36 that is positioned and supported on the upper surface of the processing table of the press machine, and the upper plate 37 installed above the lower plate 36. In addition to the roll 31, a head 38, a spindle unit 39, a reduction gear unit 40, and a drive motor 41 are installed below the roll 31. The die unit 23 can be easily replaced with various types prepared according to the shape and size of the workpiece (the material 18 to the first intermediate material 19). The head 38 is supported on the lower end portion of the rotating shaft constituting the spindle unit 39 coaxially with the rotating shaft, and the shape and size of the workpiece, the central axis X ₃₁ ( Various types prepared according to the inclination angle of FIG. 2) can be easily replaced. The type of the press machine is not particularly limited. Various general-purpose press machines (mechanical press and hydraulic press can be used) can be used. However, in the case of this example, the ram stroke speed (for example, constant speed) can be easily set as the press machine, and the roll 31 is rotated once (revolved) in combination with the drive motor 41 described below. It uses a servo press that can precisely control the amount of crushing during the process. The point that a servo press is used as the press working machine is the same in the swing forging and rolling processes described later.

  The fixed housing constituting the spindle unit 39 is supported and fixed to the lower surface of the upper plate 37. The rotary shaft rotatably supports the upper end portion or the intermediate portion thereof on the fixed housing, and supports and fixes the head 38 on the tip end portion (lower end portion). Further, a reduction large gear serving as an output portion of the reduction gear unit 40 is fixed to a portion near the lower end of the intermediate portion of the rotation shaft, and a reduction small gear serving as an input portion of the reduction gear unit 40 is connected to the drive motor 41. It is fixed to the output shaft. With this configuration, the head 38 can be driven to rotate at a low speed and with a large torque by the drive motor 41. The roll 31 is rotatably supported on the head 38 with a predetermined inclination angle as described above. With the above configuration, the roll 31 can be revolved around the central axis of the spindle unit 39 by the drive motor 41. The rotation of the roll 31 is automatically performed by revolving the roll 31 while pressing the processing surface 32 of the roll 31 against the upper end surface of the workpiece. The downward pressing of the roll 31 is performed by lowering the ram of the press machine.

  As described above, in the case of this example, the die unit 23, the roll 31, and the core elements necessary for swing forging are provided between the upper surface of the lower plate 36 and the lower surface of the upper plate 37. A head 38, the spindle unit 39, the speed reducer unit 40, and the drive motor 41 are installed to form a die set. For this reason, it is possible to easily change the setup for processing different types of workpieces with little or no production interruption. For example, during production of a metal ring-shaped part of a certain model number, the assembly of core elements relating to a separately prepared die set is completed in another place in advance, and after the production of the certain model number is completed, If the die set used for production is taken out of the press machine and the separately prepared die set is attached to the press machine, production can be resumed immediately. The taken-out die set is assembled with core elements for another model number to be produced next in another place until the next setup change. By adopting such a setup change and production flow, it is possible to produce many types of model numbers with almost no production interruption.

  As a specific procedure for attaching the die set to the press machine in a short time, first, slide the die set on the table of the press machine and position the die set using a predetermined positioning means such as a positioning pin. To do. Next, the lower plate of the die set is bolted to the table of the press machine, and the upper plate is bolted to the ram, and production is started using the die set. In the case of this example, the die set includes guide posts 42 and 42 and guide pushes 43 and 43 for preventing rolling during processing. The core elements can be easily assembled and the core elements can be easily assembled, and the setup of the die set can be easily changed. Therefore, depending on the model number, it may be necessary to change the core elements in various ways, and in some cases, it may be necessary to assemble the core elements and parts with a very complicated configuration. It is possible to produce a variety of products in small quantities with almost no production interruption.

  A servo motor is preferably used as the drive motor 41. The first reason for this is to accurately regulate the swing rotation speed. That is, in rocking forging, the amount of reduction per rotation affects the deformation of the workpiece. The amount of reduction is related to the stroke (the amount by which the ram is lowered) and the swing rotational speed, and a servo motor is used to control (properly regulate) the swing rotational speed. The second reason is that since the roll 31 generates heat during forming by swing forging, it is necessary to release heat from the work piece even during forming, and the swing rotational speed is set to a low rotational speed (10 Hz or less). Therefore, use a servo motor that stabilizes the torque even at low speeds. The third reason is that since the installation space is limited because it is necessary to incorporate it into the die set, a small servo motor that can obtain the required torque is used.

  In addition, the processing load of the swing forging can be suppressed to be lower than that of the general cold upset forging {for example, 29.4MN (3000 tonf)]. However, if the metal ring-shaped part having an outer diameter of about 200 to 400 mm is to be produced if it is about 980 kN (100 tonf), the processing using the material 18 as the first intermediate material 19 is also performed in this way. The processing of using the first intermediate material 19 as the second intermediate material 20 can be performed without any problem, except that the components 23, 31, 38, 39, 40, and 41 are formed on the upper surface of the lower plate 36 and the upper plate 37. In order to incorporate the die set between the lower surface and the die set, it is necessary to secure a gap between the plates 36 and 37 (the overall height of the die set increases). And the interval In order to ensure it, a press machine with a capacity of about 1470-5880 kN (150-600 tonf) is used.

  Further, during the rocking forging process, the die unit 23 and the roll 31 are not horizontally shaken (does not roll), the core (center axis) is stable, parallelism, perpendicularity, etc. In order to stabilize the accuracy, the guide posts 42, 42 planted vertically upward from the upper four corners of the lower plate 36 and the guide bushes suspended vertically downward from the lower four corners of the upper plate 37 43 and 43 are engaged with each other so as not to rattle at least during the progress of the swing forging, and freely in relative displacement in the vertical direction. With this configuration, the die unit 23 and the roll 31 are prevented from shaking in the horizontal direction and the core is stabilized regardless of the swing forging which is forming while generating an uneven load. The first intermediate material 19 can be processed accurately without applying excessive force to the die unit 23 and the roll 31. The guide posts 42 and 42 and the guide bushes 43 and 43 have a function that centering can be easily performed and core elements can be easily assembled as described above.

In order to process the material 18 into the first intermediate material 19 by the die set having the above-described configuration, the material 18 is set in the die unit 23 as shown in FIG. Thereafter, while rotating the roll 31 by the drive motor 41, the upper plate 37 provided with the roll 31 is pressed downward to control the crushing amount per revolution as shown in FIG. Lower to the state shown. In this process, the material 18 is processed into the first intermediate material 19 as described with reference to FIG.

  When the material 18 is processed into the first intermediate material 19 as described above, the first intermediate material 19 is then processed into the second intermediate material 20 by backward extrusion. In the case of this example, since it is intended to produce a variety of products in small quantities, if the required number of the first intermediate material 19 is processed, it is mounted on the press machine for processing the first intermediate material 19. The above die set is removed from the press machine. Thereafter, another die set for processing the first intermediate material 19 into the second intermediate material 20 is mounted on the same press machine. As shown in FIG. 5 described below, this another die set has a die unit 23a and a roll 31a in which the structure or shape of the die unit 23a is a die set 23 for processing the material 18 into the first intermediate material 19. Although it is different from the roll 31 (see FIG. 2), it basically has a similar structure. Below, the structure of said another die set and the process of processing said 1st intermediate material 19 into said 2nd intermediate material 20 by this another die set are demonstrated. When only a small number (for example, one) of press machines can be used, a plurality of processes are performed with one press machine as described above. On the other hand, if more press machines can be used, a press machine may be prepared for each process to constitute a production line. If the production line is configured, the productivity of the same model number can be increased, which is advantageous when mass-producing a specific model number. Further, when a large number of press machines can be used, the press machine is produced by changing the configuration of the press machine according to the number of ring-shaped parts to be manufactured.

  The die unit 23a is obtained by directly fixing the peripheral wall block 30a on the upper surface of the fixed plate 24a, and is not provided with the floating plate 28 and the springs 26 and 26 (see FIG. 2). The roll 31a has a two-step structure in which the processed surface 32a has a stepped surface 44 at a radially intermediate portion, and a central portion and a portion closer to the outer diameter are inclined by the same angle in the same direction. Although the inclination direction and inclination angle of each part and the inclination angle of the roll 31a as a whole are the same as those of the roll 31 shown in FIG. 2, they are not necessarily the same. The outer diameter of the stepped surface 44 is made smaller toward the base end of the roll 31a. Then, in a state where the entire roll 31a is inclined and incorporated in the die set, the direction of the portion of the step surface 44 where the first intermediate material 19 to the second intermediate material 20 are processed is between these two intermediate surfaces. The materials 19 and 20 are oriented in the direction of the central axis.

  In order to process the first intermediate material 19 into the second intermediate material 20, first, as shown in FIG. 5A, the first intermediate material 19 is fitted into the peripheral wall block 30a. The inner diameter of the peripheral wall block 30a is slightly larger than the outer diameter of the first intermediate material 19 (by a value as small as possible so that the inner fitting work can be easily performed). Therefore, the first intermediate material 19 is placed at a predetermined position on the upper surface of the fixing plate 24a with the first intermediate material 19 fitted in the peripheral wall block 30a. Therefore, the roll 31 a is pressed downward while rotating, and the center portion of the processed surface 32 a of the roll 31 a is pressed against the center portion of the upper surface of the first intermediate material 19. As a result, as shown in FIG. 5B, the central portion of the first intermediate material 19 is recessed in a circular shape, and a portion near the outer diameter of the first intermediate material 19 enters the peripheral portion of the step surface 44. The rear extrusion process is performed. At the same time, the outer peripheral surface of the first intermediate material 19 is strongly pressed against the inner peripheral surface of the peripheral wall block 30a. Then, at the stage where the central portion is recessed to some extent, the outer diameter side portion hits the outer diameter portion of the processed surface 32a and is smoothed at the outer diameter portion, and the second intermediate material 20 is smoothed. The molding work is completed.

  If the roll 31a continues to rotate near the bottom dead center for an excessively long time after this forming operation is completed, there is a possibility that burrs may occur on the outer peripheral edge of the obtained second intermediate material 20. Therefore, in order to omit the trouble of removing this burr, the roll 31a is rotated for an appropriate molding time (roll rotation speed) near the bottom dead center in consideration of the variation in the volume of the material 18. Then, the processing operation of the second intermediate material 20 is finished. The disk-shaped second intermediate material 20 having the circular recess 45 at the center of the upper surface thus obtained is pushed out of the peripheral wall block 30a by the knockout pin 33a and taken out from the die unit 23a. Sent to the process.

  As described above, when the first intermediate material 19 is processed by backward extrusion, the shape accuracy of the second intermediate material 20 obtained, that is, the shape of the circular recess 45, the shape of the outer peripheral surface, and the shapes of both end surfaces in the axial direction are obtained. In addition, the perpendicularity and the coaxiality between the circular recess 45 and the outer peripheral surface can be improved. In addition, as for the above-described rear extrusion process, if the general forging process as shown in FIG. 6 is performed, not only the molding load becomes too high, but also as in the case described in FIG. Thus, there is a possibility that the die 35a is broken as the punch 34a is lowered, and it is difficult to ensure the shape accuracy of the workpiece due to the lack of thickness. On the other hand, in the case of this example, since the sealing is not completely closed until the processing is completed, the surface of the first intermediate material 19 or the second intermediate material 20 is a die including the roll 31a and the peripheral wall block 30a. It is possible to ensure the shape accuracy of the workpiece without hitting the unit 23a with a gap that causes a lack of thickness. By processing the first intermediate material 19 into the second intermediate material 20, the fracture surface can be reduced, defects due to microcracks can be eliminated, and the yield of the material can be improved.

In the above-described backward extrusion process and upsetting process in the preceding process, it is preferable to control the crushing amount per revolution by servo-controlling both the revolution number of the tool and the stroke speed. . Accordingly, a servo press is usually used as a press machine used for both processes. However, only one of the revolution number and stroke speed of the tool may be servo controlled. That is, for example, the stroke speed of the ram of the mechanical press can be detected by a sensor, and the rotation speed can be controlled by a servo motor in accordance with the stroke speed to control the crushing amount per revolution.

  The second intermediate material 20 obtained as described above is placed between the processing table and the ram of the press machine after the vertical direction is reversed after taking out from the die unit 23a. Set on a die set as shown in 7. Then, with this die set, a portion corresponding to the bottom of the circular recess 45 is punched out to form an annular third intermediate material 21. The die set used for this punching process is for holding down the die unit 23b for holding the second intermediate material 20, the counter punch 46 and punch 47 for punching the portion, and the second intermediate material 20. Of the floating punch 48.

  The die unit 23b is formed by fixing a peripheral wall block 30b for fitting (press-fitting) the second intermediate material 20 on the upper surface of the fixing plate 28a for placing the second intermediate material 20 thereon. . The counter punch 46 is inserted through the center hole 49 of the fixed plate 28a so as to be movable up and down, and has an outer diameter dimension that can be fitted (lightly press-fitted) into the circular recess 45 without a gap. The punch 47 is disposed above the counter punch 46 and concentric with the counter punch 46, and is pressed downward by the ram. Further, the floating punch 48 is externally fitted around the punch 47 so as to be movable up and down with respect to the punch 47, and is given downward elasticity by a lower pressure means 50 such as a spring.

  In order to punch out the portion corresponding to the bottom of the circular recess 45 in the second intermediate material 20 using the die set as described above, first, as shown in FIG. The second intermediate material 20 is fitted (press-fitted) into the upper end portion of the peripheral wall block 30b with the circular recess 45 down, and the upper end portion of the counter punch 46 is fitted (lightly press-fitted) into the circular recess 45. From this state, as shown in FIG. 7B, the punch 47 and the floating punch 48 are lowered, and the front end surface (lower end surface) of the punch 47 is pushed into the center of the upper surface of the second intermediate material 20. At the same time, the lower surface of the floating punch 48 suppresses the portion of the second intermediate material 20 that is closer to the outer diameter of the upper surface. In this state, the second intermediate material 20 is in a so-called hydrostatic pressure state in which the entire surface is suppressed. Therefore, the punch 47 is further lowered to punch out a portion of the second intermediate material 20 corresponding to the bottom of the circular recess 45 as shown in FIG. And In this example, since the shape accuracy of the second intermediate material 20 is good, the fixing plate 28a, the peripheral wall block 30b, the counter punch 46, the punch 47, and the floating punch 48 With the second intermediate material 20 covered, the gap between the surface of the second intermediate material 20 and the mating surface can be made substantially zero. For this reason, the hydrostatic pressure state can be sufficiently realized.

  With the punching process {in the process of (B) → (C) in FIG. 7, (A) → (B) → (C) in FIG. 8]} in the radial intermediate portion of the second intermediate material 20, A force in the shearing direction is applied between the inner peripheral edge of the upper end opening of the center hole 49 of the fixing plate 28a constituting the die unit 23b and the outer peripheral edge of the front end surface of the punch 47. By this force, as shown in FIG. 8B, cracks 7a and 7b are generated (run) toward the central portion in the thickness direction of the second intermediate material 20. At the moment when the tips of both cracks 7a and 7b are continuous, the central portion of the second intermediate material 20 is separated from the outer diameter portion, and the central portion is discharged as scrap 8a. Is the third intermediate material 21.

  On the inner peripheral surface of the third intermediate material 21, as shown in FIG. 9, the sag 9a, the shearing surface 10a, the fracture surface 11a, and the circular recess are sequentially formed from the upper side which is the pushing side of the punch 47. There is a smooth surface 52 formed by rocking forging, which is the inner peripheral surface of 45. In the case of this example, when the circular recess 45 is provided on the side opposite to the pushing direction of the punch 47, the fracture surface 11a is formed in the axially intermediate portion when viewed as the third intermediate material 21 as a whole. It exists. Further, by punching the central portion of the second intermediate material 20 under a hydrostatic pressure state, the width dimension of the shearing surface 10a is increased compared to the case where it is not performed under a hydrostatic pressure state. The width dimension of the fracture surface 11a can be made narrower. In this way, by narrowing the width of the fracture surface 11a and positioning the fracture surface 11a in the middle portion in the axial direction, the fracture surface 11a of the third intermediate material 21 is crushed during the cold rolling process described below, and a minute Even if the concavities and convexities that lead to the occurrence of cracks are crushed (smoothed) and subjected to significant diameter expansion, the occurrence of crack damage can be prevented.

  Although it is possible to completely eliminate the fracture surface 11a, in that case, the floating punch 48 is moved downward by a very large force in the process of (B) → (C) in FIG. It is necessary to press. For this purpose, it is necessary to install a hydraulic device for generating such a large force in the punching device, which complicates the device and increases the cost. In order to prevent the occurrence of minute cracks during the rolling process described below, as long as the fracture surface 11a is positioned at the intermediate portion in the axial direction of the third intermediate material 21, some fracture surface 11a remains. There is no problem. Therefore, in the case of this example, a simple structure such as a spring or a gas cushion that can be configured in a small size is adopted for the lower pressure means 50.

  In this example, in order to make the width of the fracture surface 11a narrower, the clearance between the punch 47 and the center hole 49 {("inner diameter of the center hole 49"-"outer diameter of the punch 47"). / 2} is made smaller than in the case of normal punching. Specifically, the clearance is set to about 1 to 10% of the thickness of the center portion (circular recess 45 portion) of the second intermediate material 20. Further, the allowance for press-fitting the upper end of the counter punch 46 into the circular recess 45 is about 0.1 to 0.5% of the outer diameter of the second intermediate material 20. Note that the nominal value of the press-fitting allowance (target press-fitting allowance) is appropriately determined by trial production or the like performed before actual production. Further, the load required for the punching process may be lower than the load for normal forging such as upsetting forging and backward extrusion, and can be determined in the same manner as in the normal pressing.

  The third intermediate material 21 made as described above is disposed at a plurality of intervals (for example, at equal intervals in the circumferential direction) after raising the punch 47 and the floating punch 48 by raising the ram. The other three) knockout pins 51, 51 are pushed out from the inner diameter side of the peripheral wall block 30b and sent to the next step.

  The third intermediate material 21 is subjected to a cold rolling process to be expanded in diameter to form a fourth intermediate material 22 having a larger diameter than the third intermediate material 21 as shown in FIG. The fourth intermediate material 22 is generally formed with a raceway groove or the like thereafter by a lathe process, but the raceway process can be omitted by forming the raceway groove by the cold rolling process. . In any case, if the metal ring-shaped part is a bearing ring for a radial rolling bearing, after forming the raceway groove, finish processing such as heat treatment and grinding is performed, and the raceway for the radial rolling bearing. Completed as a circle.

  Such cold rolling processing can also be performed by a dedicated rolling processing device as described in Patent Documents 4 to 6. However, the dedicated rolling processing apparatuses described in each of these patent documents are also suitable for processing a small variety of mass-produced products, but are not suitable for processing a large variety of small-volume products. In addition, when making a large-diameter metal ring-shaped part, a large dedicated device is required. Therefore, in the case of this example, even in the cold rolling process as described above, a die set as shown in FIGS. 10 to 12 is installed between the processing table of the press machine and the ram. This die set is arranged so as to be rotatable about a horizontal axis, and also includes a mandrel 15a, a pair of first support rolls 53, 53, a pair of second support rolls 54, 54, A forming roll 16a, a reduction gear unit 55, and a drive motor 56 are provided. Among these, the mandrel 15a, the pair of first support rolls 53, 53, and the pair of second support rolls 54, 54 are located above the lower plate 57 supported on the upper surface of the processing table of the press machine. Is provided. Further, the mandrel 15a can be displaced in the axial direction as indicated by an arrow in FIG. 12A, and the third intermediate material 21 through the third material 21 to be processed around the mandrel 15a. The four intermediate materials 22 can be attached and detached. The axial movement of the mandrel 15a is performed by a direct acting actuator 61 such as a hydraulic cylinder or an air cylinder. On the other hand, the forming roll 16a, the speed reducer unit 55, and the drive motor 56 are provided below an upper plate 58 supported on the lower surface of the ram of the press machine.

  The two positions in the axial direction of the mandrel 15a are the outer peripheries of the upper ends of the first support rolls 53, 53 provided apart from each other in the left-right direction in FIGS. It is in contact with the surface. Further, the outer peripheral surfaces of the lower end portions of the first support rolls 53, 53 are both separated from each other in the front and back directions of FIGS. It is made to contact | abut to the outer peripheral surface of the upper end part of 54,54. Further, these support rolls 53 and 54 are rotatably supported by a lower support frame 59 provided on the upper surface of the lower plate 57. With this configuration, the mandrel 15a is allowed to rotate while supporting a radial load applied to the mandrel 15a during the cold rolling process. Therefore, the rotation center axis of the mandrel 15a and the rotation center axes of the support rolls 53 and 54 are parallel to each other.

  The first support rolls 53 and 53 are supported on the lower support frame 59 by cantilevered support shafts. Therefore, there is no support shaft between the first support rolls 53, 53, and even if the fourth intermediate material 22 having a large diameter is processed as shown in FIG. The four intermediate materials 22 do not interfere with each other. However, the second support rolls 54 and 54 that finally support the processing load are supported by the lower support frame 59 in a double-supported manner to ensure load bearing performance.

  The forming roll 16a is rotatably supported on an upper support frame 60 fixed to the lower surface of the upper plate 58. The forming roll 16 a can be driven to rotate by the drive motor 56 via the speed reducer unit 55. Further, the forming roll 16a is supported on the upper support frame 60 by a sufficiently thick support shaft so as to be able to support a large processing load. Therefore, no support roll is provided on the upper support frame 60 side. Regarding the drive motor 56, a servo motor is preferably used for the same reason as that of the above-described swing forging die set.

  In order to process the third intermediate material 21 into the fourth intermediate material 22 using the cold rolling die set as described above, first, as shown in FIG. The third intermediate material 21 is loosely fitted. In this operation, the mandrel 15a is retracted to the left in FIG. 10A, the third intermediate material 21 is brought into a predetermined position, and then the mandrel 15a is moved to the right in FIG. By moving forward. The third intermediate material 21 is brought in by a robot arm or by a worker's hand. In the state where the third intermediate material 21 is set in this way, the lower half portion of the third intermediate material 21 is disposed between the upper ends of the first support rolls 53, 53. Further, the molding roll 16 a is positioned immediately above the third intermediate material 21.

From this state, the ram of the press machine is lowered while the forming roll 16a is rotationally driven by the drive motor 56 via the reduction gear unit 55. Then, the molding roll 16 a is pressed downward through the upper plate 58, and the outer peripheral surface of the lower end portion of the molding roll 16 a is strongly pressed against the outer peripheral surface of the upper end portion of the third intermediate material 21. As a result, the third intermediate material 21 is strongly pressed between the outer peripheral surface of the mandrel 15a and the outer peripheral surface of the molding roll 16a, from the state shown in FIG. 10 to the state shown in FIG. The diameter gradually expands to become a fourth intermediate material 22 as shown in FIG. In this way, in the process of using the third intermediate material 21 as the fourth intermediate material 22, no cracks are generated at the fracture surface 11 a existing in the axially intermediate portion of the inner peripheral surface of the third intermediate material 21. The mandrel 15a is sufficiently crushed by the outer peripheral surface to become a smooth surface. That is, when the diameter of the third intermediate material 21 begins to expand, a groove portion that becomes a starting point of cracking as described with reference to FIG. 16 is formed on the inner peripheral surface of the third intermediate material 21. The fourth intermediate material 22 can be processed with a high yield. The fourth intermediate material 22 obtained in this way is retracted and removed from the mandrel 15a as shown in FIG. 12, and sent to the next finishing step. This take-out operation is also performed by a robot arm or by a worker's hand.

  In the rolling process, servo control is performed on both the rotational speed of the third intermediate material 21 to the fourth intermediate material 22 and the stroke speed of the forming roll 16a, which are ring-shaped materials. The crushing amount per rotation of the third intermediate material 21 to the fourth intermediate material 22 is preferably controlled. However, only one of the rotation speed of the third intermediate material 21 to the fourth intermediate material 22 and the stroke speed of the forming roll 16a may be servo controlled. For example, the stroke speed of the ram of the mechanical press may be detected by a sensor, and the rotation speed may be controlled by a servo motor in accordance with the stroke speed to control the crushing amount per rotation. Thus, the point that the stroke speed and the number of revolutions are important parameters for the control are the same as in the case of the control of the upsetting process and the backward extrusion process by the above-mentioned swing forging.

The material 18 used when implementing the present invention is mainly bearing steel or carburized steel, and lubrication for processing is performed by a bonder process. However, when the area of the cut surface (both end surfaces in the axial direction) of the material 18 is large, the process of using the material 18 as the first intermediate material 19 and the subsequent processes can be lubricated by oil application. .
In addition, the processing temperature is basically set to be cold throughout the entire process, but when the diameter of the metal ring-shaped part to be manufactured is particularly large, it can be formed warm (200 to 700 ° C.).
Also, in the press working machine used in the process of using the material 18 as the first intermediate material 19 and subsequent processes, the amount of reduction per rotation is important in each process, so that it can be adjusted according to the number of rotations of the roll. In order to control the descending speed of the press machine, it is preferable to use a servo press. However, the press machine can be used for any of a mechanical press, a hydraulic press, and a transfer press.

DESCRIPTION OF SYMBOLS 1 Material 2 1st intermediate material 3 2nd intermediate material 4 3rd intermediate material 5 Die 6 Punch 7a, 7b Crack 8, 8a Scrap 9, 9a Sag 10, 10a Shear surface 11, 11a Fracture surface 12, 12a Burr 13 Central hole 14 Cold rolling processing device 15, 15a Mandrel 16, 16a Forming roll 17 Crack 18 Material 19 First intermediate material 20 Second intermediate material 21 Third intermediate material 22 Fourth intermediate material 23, 23a, 23b Die unit 24, 24a fixed Plate 25 Floating die 26 Spring 27 Anchor block 28, 28a Floating plate 29 Center hole 30, 30a, 30b Circumferential wall block 31, 31a Roll 32, 32a Work surface 33, 33a Knockout pin 34, 34a Punch 35, 35a Die 36 Lower plate 37 Upper plate 38 Head 3 9 Spindle unit 40 Reducer unit 41 Drive motor 42 Guide post 43 Guide bush 44 Stepped surface 45 Circular recess 46 Counter punch 47 Punch 48 Floating punch 49 Center hole 50 Lower pressure means 51 Knockout pin 52 Smooth surface 53 First support roll 54 First Two support rolls 55 Reduction gear unit 56 Drive motor 57 Lower plate 58 Upper plate 59 Lower support frame 60 Upper support frame 61 Actuator

Claims (12)

  A cylindrical material is crushed in the axial direction by upsetting to form a disk-shaped first intermediate material, and then the central portion of one surface of this first intermediate material is crushed in the axial direction and the portion closer to the outer diameter of the axial direction. Is made into a second intermediate material having a circular concave portion at the central portion on one side in the axial direction by a backward extrusion process that protrudes in a direction opposite to the crushing direction, and subsequently, than the circular concave portion on the one side surface in the axial direction of the second intermediate material. By pressing the punching punch against the central part on the other side in the axial direction with the outer diameter close part held down by the die, the part corresponding to this circular recess is punched and removed at the central part of the second intermediate material. An annular third intermediate material is formed, and then the third intermediate material is expanded in diameter by rolling to form an annular fourth intermediate material. Further, a predetermined finishing process is applied to the fourth intermediate material to form a metal ring. Like parts Manufacturing method of the genus made ring-shaped parts.   In addition to the outer peripheral surface, the inner peripheral surface of the circular recess, and the outer peripheral surface near the outer diameter of the second recess in addition to the portion of the second intermediate material that is closer to the outer diameter on one side in the axial direction, The manufacturing method of the metal ring-shaped component according to claim 1, wherein a punch is pressed against the second intermediate material in a state of being performed.   The back extrusion process using the first intermediate material as the second intermediate material, the central axis of these intermediate materials on one side in the axial direction of both intermediate materials with the outer peripheral surface and other axial surfaces of both intermediate materials suppressed. The center axis is inclined with respect to the workpiece, and the direction of the portion of the processing surface that contacts the first intermediate material is perpendicular to the central axis of both the intermediate materials. 3. The metal ring-shaped component according to claim 2, wherein a portion closer to the outer diameter of one axial surface of the second intermediate material and the entire other axial surface are flat surfaces perpendicular to the central axis of the second intermediate material. Manufacturing method.   Processing the material in the axial direction by crushing the material in the axial direction, with the material placed in a die that regulates the outer peripheral surface of the first intermediate material, on one side in the axial direction of this material, The center axis of the material or first intermediate material is inclined with respect to the central axis, and the direction of the portion of the processing surface that contacts the material or first intermediate material is the center axis of the material or first intermediate material. The method for manufacturing a metal ring-shaped part according to any one of claims 1 to 3, wherein the method is performed by swing forging in which a roll that is perpendicular to the direction is pressed.   Regarding the rolling process, the adjustment of at least one of the rotational speed and stroke speed of the tool to be used is performed by servo control. Production method.   The metal ring-shaped part according to any one of claims 3 to 5, wherein at least one of a rotational speed and a stroke speed of a tool to be used is adjusted by servo control with respect to swing forging. Manufacturing method.   The method for manufacturing a metal ring-shaped part according to any one of claims 5 to 6, wherein the stroke speed is adjusted by using a press machine that servo-controls the stroke of the ram.   The lower plate placed on the upper surface of the processing table of the press machine, the holding portion for holding the workpiece provided on the upper surface of the lower plate, and the press installed above the lower plate An upper plate that is pressed downward by the ram of the processing machine, a processing tool that is provided on the lower surface of the upper plate and presses the workpiece as the upper plate is lowered, and a part of the upper plate A metal part plastic working apparatus provided with an electric motor that is supported and fixed to rotate the working tool.   The holding portion is a die having an inner peripheral surface shape that matches the outer peripheral surface shape at the time of completion of processing of the workpiece, and the processing tool is a roll for plastically deforming the workpiece by swing forging. A plastic working apparatus for metal parts according to claim 8.   The holding part is a mandrel that is arranged in a horizontal direction and rotates in a state in which an annular work piece is loosely fitted, and the work tool rotates while pressing the work piece against the mandrel. The plastic working apparatus for metal parts according to claim 8, which is a forming roll for expanding the diameter of the work piece.   The plastic working apparatus for metal parts according to any one of claims 8 to 10, wherein the electric motor is a servo motor capable of adjusting a rotation speed.   The plastic working of a metal part according to any one of claims 8 to 11, wherein a press working machine having a ram for pressing the upper plate has a function of servo-controlling the stroke of the ram. apparatus.

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