JP4274439B2 - Molding equipment for closed forging - Google Patents

Description

  The present invention relates to a forging die apparatus used for shunt blockage forging.

  Conventionally, as a method of manufacturing mechanical parts such as gears by forging, for example, those described in Patent Document 1 and Patent Document 2 are known.

The spur gear forging method of Patent Document 1 described above is a first machining step in which a primary working gear is formed by upsetting into a primary gear having a gear shape set smaller than the gear-shaped tooth profile of the spur gear from which a material is to be obtained. Each of these steps comprises a second processing step in which a material is freely flowed in a portion other than the tooth profile and compression-molded into a secondary processing gear, and a third processing step in which the secondary processing gear is cast into a final product. Is performed by cold forging, and the ironing allowance at the time of ironing is formed stably, so that there is an effect that a highly accurate product can be obtained with a low load.
Moreover, the extrusion method of the above-mentioned patent document 2 is formed by extruding with a punch having a hole, forming a convex part from the hole part of the punch, and pressurizing the convex part release end of this part with a predetermined pressure. This is a method of extruding and reducing or removing the pressure before the end of processing, and has the effect of greatly reducing the maximum load acting on the mold near the bottom dead center.

JP-A-5-154598 Japanese Patent No. 2534899

  However, in the forging method of Patent Document 1, since the material is formed smaller than the gear-shaped tooth profile of the spur gear to be obtained in advance, one or two steps are required to form the material into a gear shape. Since the number of processes is large, for example, the forging of the material requires 3 processes, forging takes time and the productivity is poor.

  In addition, since the forging is performed by exchanging the punches for each process, the replacement work becomes complicated, and it is necessary to prepare a plurality of types of punches and mandrels in advance.

On the other hand, in the extrusion method of Patent Document 2, the pressing member provided on the upper punch performs backward extrusion while partially restricting the flow of the material, and reduces or eliminates the pressing force of the pressing member before the end of processing. As a result, a high surface pressure acts on the mold from the start of molding, thereby causing problems such as seizing the mold and shortening the life of the mold early.
In the extrusion method of the above publication, since the pressure member is provided only on the upper punch side, the pressurizing force of the upper punch and the lower punch is non-uniform and the material flows only in one direction. The product has a non-uniform fiber flow, resulting in a decrease in strength of the product and defects such as cracks and sink marks in the product.

  The present invention was made to remedy such problems, and provides a closed forging die device that can obtain a high closing force by means of a pressurizing means. The purpose is to make it easy to obtain.

In order to achieve the above object, the invention according to claim 1 closes the cavity 1a of the upper mold 1 attached to the slide 6 side and the cavity 2a of the lower mold 2 installed on the bolster 17 side, and And a closed forging die apparatus for closing and forging the work 7 by pressurizing and diverting the work 7 in the cavities 1a and 2a with the upper counter punch 8 and the lower counter punch 22 provided in the lower mold 2,
The upper support member 4 is attached to the lower surface of the slide 6 via the upper cylinder block 5, and the upper mold 1 is attached to the lower surface of the first elevating member 4a accommodated in the upper support member 4.
The upper cylinder block 5 is provided with a first outer cylinder 11, and the first piston 11b can be slid up and down in the first outer cylinder 11 and is moved downward by the pressure oil in the first hydraulic chamber 11c. The first piston 11b is brought into contact with the lower surface of the first working piston 10, and the first working piston 10 is brought into contact with the upper surface of the first elevating member 4a. A hydraulic pressure generating device 25 for supplying pressure oil in the hydraulic chamber 11c of the first hydraulic chamber 11c, and pressurizing the upper mold 1 from above;
A first inner cylinder 12 is provided at the center of the first outer cylinder 11, and a second piston 12a that pushes the upper counter punch 8 downward is slidable up and down in the first inner cylinder 12. The upper counter punch 8 is provided with a hydraulic pressure generating device 25 that accommodates and fills the second hydraulic chamber 12b that moves the second piston 12a downward and fills the pressure oil and drains the tank (35). As a back pressure applying means for applying back pressure to
The lower support member 14 is attached to the upper surface of the bolster 17 via the lower cylinder block 16, and the lower mold 2 is attached to the upper surface of the second elevating member 14a accommodated in the lower support member 14.
A second outer cylinder 19 is attached to the lower cylinder block 16, and a third piston 19b can be slid up and down in the second outer cylinder 19 and is moved upward by pressure oil in the third hydraulic chamber 19c. The upper surface of the third piston 19b is in contact with the second operating piston 18, and the second operating piston 18 is in contact with the lower surface of the second elevating member 14a. 3 is provided with a hydraulic pressure generator 25 for supplying pressure oil in the hydraulic chamber 19c, and pressurizes the lower mold 2 from below.
A second inner cylinder 20 is provided at the center of the second outer cylinder 19, and a fourth piston 20 a that pushes the lower counter punch 22 upward is slidable in the second inner cylinder 20. The lower counter punch 22 is provided with a hydraulic pressure generating device 25 that accommodates and fills the fourth hydraulic chamber 20b that moves upward through the fourth piston 20a and performs drainage to the tank (35). As a back pressure applying means for applying back pressure to
When the slide 6 descends, pressure oil is supplied to the first hydraulic chamber 11c to move the first piston 11b downward, and pressure oil is supplied to the third hydraulic chamber 19c to provide third pressure. The piston 19b is moved upward, the upper die 1 and the lower die 2 are pressurized from above and below by the pressurizing means to close the cavities 1a and 2a on both sides, and the second hydraulic chamber 12b is filled with pressure oil. The back pressure is applied to the upper counter punch 8, and the fourth hydraulic chamber 20b is filled with pressure oil to apply the back pressure to the lower counter punch 22 to pressurize the work 7 in the cavities 1a and 2a. Before the slide 6 ascends and when the work 7 is filled in the cavities 1a and 2a, the pressure oil in the second hydraulic chamber 12b and the fourth hydraulic chamber 20b is drained to the tank 35, It was configured to remove back pressure. It is a closed forging die apparatus according to symptoms.

  According to the first aspect of the present invention, when the upper mold 1 is lowered together with the slide 6 and the upper mold 1 and the lower mold 2 are brought into close contact with each other, the upper mold 1 and the lower mold 2 are pressurized by the pressurizing means. Then, the cavities 1a and 2a are closed on both sides, and at the same time, the work in the cavities 1a and 2a is pressurized in the vertical direction by the upper counter punch 8 and the lower counter punch 22 by the back pressure applying means, so When the workpieces are filled in the cavities 1a and 2a, the back pressure of the upper and lower counter punches 8 and 22 is removed so that no abnormally high pressure is generated in the cavities 1a and 2a. Since high-pressure closing force can be easily obtained, large machine parts can be easily forged, and when the work is filled in the cavity, the back pressure of the back pressure applying means is removed. Since was Unishi, or mold damage abnormally high pressure occurs, die life is not reduced at an early stage.

  In addition, since a large closing force can be secured until the slide reaches the bottom dead center, the filling of the material in the cavity is improved, and a molded product having a good quality with no lack of wall is obtained. Therefore, it is not necessary to remove burrs after molding.

  Furthermore, since the upper and lower molds can be closed simultaneously by supplying hydraulic pressure to the upper and lower pressurizing means, it is possible to supply pressure oil with a single hydraulic generator, which can reduce equipment costs and block Since the hydraulic pressure only needs to be generated during forging, it is possible to reduce the size of the mold mounting parts and the like, thereby reducing the cost of the mold apparatus.

An embodiment of the present invention will be described in detail with reference to the drawings shown in FIGS.
Fig. 1 is a cross-sectional view of a mold device for closed forging for forging machine parts (hereinafter referred to as workpieces) such as inner races of constant velocity joints, bevel gears, flange parts, etc. The circuit diagram of an apparatus is shown.

In these drawings, 1 is an upper mold, 2 is a lower mold, and the upper mold 1 is detachably attached to the lower surface of the upper support member 4 via an upper mold holder 3. The upper support member 4 is an upper cylinder block 5. Is attached to the lower surface of the slide 6 of the forging press.
A cavity 1a for forming the workpiece 7 is formed at the center of the lower surface of the upper mold 1. Inside the cavity 1a, an upper counter punch 8 supported at the center of the upper mold 1 is slidable in the vertical direction. The tapered tip portion 8a protrudes from the upper side so as to be able to protrude and retract.

  An elevating member 4a for elevating and lowering the upper mold 1 is accommodated in the upper support member 4, and the upper mold 1 is attached to the lower surface of the elevating member 4a by a holder 3, and the elevating member 4a A step portion 4b is formed on the outer peripheral surface, and the step portion 4b is locked to the locking ring 4c, so that the elevating member 4a is prevented from falling out of the upper support member 4 and is moved up and down. The lower ends of the plurality of operating pins 10 are in contact with the upper surface of the member 4a.

Each operating pin 10 is provided so as to penetrate the end plate 11a of the outer cylinder 11 provided in the cylinder block 5 in the vertical direction, and the upper end surface is accommodated in the outer cylinder 11 so as to be slidable in the vertical direction. It is in contact with the lower surface of the piston 11b.
The upper side of the piston 11 b is a hydraulic chamber 11 c and is connected to a hydraulic pressure generator 25 shown in FIG. 2 through an oil passage 5 a and a pipe 29 formed in the cylinder block 5.

An inner cylinder 12 is provided at the center of the outer cylinder 11, and the lower surface of the piston 12 a accommodated in the inner cylinder 12 so as to be slidable in the vertical direction is connected to the upper counter punch 8 via a presser 13. While being in contact with the upper surface, a knockout pin 14 of a slide knockout (not shown) provided in the slide 6 is penetrated through the central portion of the piston 12a so as to be slidable in the vertical direction.
The upper side of the piston 12a is a hydraulic chamber 12b, which is filled with oil in advance, and an oil passage 5b formed in the cylinder block 5 and the first electromagnetic valve 32 and the relief valve 33 are connected in parallel. 2 is connected to the oil tank 35 of the hydraulic pressure generator 25 shown in FIG.

On the other hand, the lower mold 2 is attached to the upper surface of an elevating member 14a accommodated in the lower support member 14 via a lower mold holder 15, and the lower support member 14 is forged via a lower cylinder block 16. It is attached to the upper surface of the bolster 17 of the press.
A step portion 14b is formed on the outer peripheral surface of the elevating member 14a, and the step portion 14b is locked to the locking ring 14c. Lower ends of a plurality of operating pins 18 are in contact with the upper surface of the elevating member 14a.

Each operating pin 18 is provided so as to penetrate the end plate 19a of the outer cylinder 19 provided in the cylinder block 16 in the vertical direction, and the lower end surface is accommodated in the outer cylinder 19 so as to be slidable in the vertical direction. In contact with the upper surface of the piston 19b.
The lower side of the piston 19 b is a hydraulic chamber 19 c and is connected to the hydraulic pressure generator 25 through an oil passage 16 a and a pipe 29 formed in the cylinder block 16.

Further, an inner cylinder 20 is provided at the center of the outer cylinder 19, and the upper surface of the piston 20 a accommodated in the inner cylinder 20 so as to be slidable in the vertical direction is disposed on the lower surface of the lower counter punch 22 via a presser 21. It is in contact with.
A tapered tip portion 22a formed at the upper end of the lower counter punch 22 protrudes from a lower portion into a cavity 2a formed on the upper surface of the lower die 2, and protrudes from the center of the piston 20a. A knockout pin 23 of a bed knockout (both not shown) provided on the bed is slidably penetrated.

  The lower side of the piston 20a is a hydraulic chamber 20b, which is prefilled with oil, and an oil passage 16b formed in the cylinder block 16 and a second electromagnetic valve 36 and a relief valve 37 in parallel. It is connected to the oil tank 35 of the hydraulic pressure generator 25 through the connected pipe line 38.

  As shown in FIG. 2, the hydraulic pressure generating device 25 includes intermediate pressure generating means 26 having cylinders 26a and 26b having different diameters, and high pressure generating means 27 having cylinders 27a and 27b having different diameters. By supplying the pressure oil to the cylinders 26b, 27b on the smaller diameter side than 28, medium pressure or high pressure oil is generated in the large diameter cylinders 26a, 27a. The pressure oil generated in 27 is supplied to the hydraulic chamber 11c of the outer cylinder 11 provided on the upper die 1 side and the hydraulic chamber 19c of the outer cylinder 19 provided on the lower die 2 side through the pipe 29. It has become so.

  In FIG. 2, reference numeral 40 denotes a residual pressure extracting valve for extracting the residual pressure in the medium and high pressure generating means 26 and 27 to the oil tank 35.

Next, the operation of the above-configured closed forging die apparatus will be described.
When the work 7 is loaded into the cavity 2a of the lower mold 2 by a work conveying means (not shown) while the slide 6 is stopped at the top dead center, the upper mold 1 is lowered together with the slide 6 so that the lower surface of the upper mold 1 is moved. When the upper mold 1 and the lower mold 2 are brought into close contact with each other, pressure oil is supplied simultaneously from the intermediate pressure generating means 26 or the high pressure generating means 27 to the hydraulic chambers 11c and 19c of the outer cylinders 11 and 19, respectively. The mold 2 is pressurized from above and below to close the cavities 1a and 2a (this is called double-side closing).

  At the same time, the work 7 in the cavities 1a and 2a is given back pressure in the vertical direction by the tip portions 8a and 22a of the upper counter punch 8 and the lower counter punch 22 projecting into the cavities 1a and 2a. The work 7 is forged in the closed cavities 1a and 2a by diverting into 2a (this is called bilateral diversion).

Then, the divided work 7 is filled in the cavities 1a and 2a, and the first and second electromagnetic valves 32 and 36 are opened immediately before the internal pressure rises, and the hydraulic chambers 12b and 20b of the inner cylinders 12 and 20 are opened. The pressure oil is drained to the oil tank 35.
As a result, the back pressure applied to the upper and lower counter punches 8 and 22 is removed, and the pressure distribution of the workpiece 7 is stopped, so that the increase in the internal pressure of the cavities 1a and 2a is suppressed, and the internal pressure rises abnormally. This prevents the mold from being damaged.

  When the forming of the work 7 is completed as described above, as the slide 6 starts to rise together with the upper mold 1, the knock pin 14 is first pushed down by the slide knockout, and the work 7 attached to the upper mold 1 is knocked out. Then, as the slide 6 further rises, the knockout pin 23 is pushed up by bed knockout and the workpiece 7 is knocked out from the lower mold 2, and then the workpiece 7 that has been molded is carried out by the workpiece transfer device.

  By repeating the above operation, the workpiece 7 is closed and forged, and the upper and lower molds 1 and 2 are closed on both sides, and at the same time, the workpiece 7 is forked by the upper and lower counter punches 14 and 22, and forging is performed. There will be no good quality molded products.

1 is a cross-sectional view of a closed forging die device according to an embodiment of the present invention. 1 is a circuit diagram of a hydraulic pressure generator used in a closed forging die device according to an embodiment of the present invention. FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Upper mold | type, 1a ... Cavity, 2 ... Lower mold | type, 2a ... Cavity, 6 ... Slide, 7 ... Workpiece | work, 8 ... Upper counter punch, 11 ... Pressurization means (outer cylinder), 12 ... Back pressure provision means (inner side) Cylinder), 17 ... bolster, 19 ... pressure means (outer cylinder), 20 ... back pressure applying means (inner cylinder), 22 ... lower counter punch

Claims (1)

The upper mold (1) cavity (1a) mounted on the slide (6) side and the lower mold (2) cavity (2a) installed on the bolster (17) side are closed, and the upper mold (1) And the upper counter punch (8) and the lower counter punch (22) provided in the lower die (2), the work (7) in the cavities (1a) and (2a) is divided by pressurizing and the work (7) is closed. In the mold equipment for closed forging to forge,
The upper support member (4) is attached to the lower surface of the slide (6) via the upper cylinder block (5), and the upper surface of the first elevating member (4a) accommodated in the upper support member (4) is Install the mold (1),
A first outer cylinder (11) is provided in the upper cylinder block (5), and a first piston (11b) can be slid up and down in the first outer cylinder (11), and a first hydraulic chamber. (11c) is accommodated so as to move downward with the pressurized oil, the lower surface of the first piston (11b) is brought into contact with the first working piston (10), and the first working piston (10). Is provided in contact with the upper surface of the first elevating member (4a), and a hydraulic pressure generator (25) for supplying pressure oil into the first hydraulic chamber (11c) is provided so that the upper mold (1) is disposed from above. Pressurizing means to pressurize,
A first inner cylinder (12) is provided at the center of the first outer cylinder (11), and a second inner cylinder (12) is pushed secondly to push the upper counter punch (8) downward. The piston (12a) is accommodated slidably up and down, the second hydraulic chamber (12b) moving downward in the second piston (12a) is filled with pressure oil, and a drain to the tank (35) is provided. Providing a hydraulic pressure generating device (25) for performing back pressure application means for applying a back pressure to the upper counter punch (8);
A lower support member (14) is attached to the upper surface of the bolster (17) via a lower cylinder block (16), and the lower surface of the second elevating member (14a) accommodated in the lower support member (14) is Install the mold (2),
A second outer cylinder (19) is attached to the lower cylinder block (16), and a third piston (19b) can slide up and down in the second outer cylinder (19), and a third hydraulic chamber. (19c) is accommodated so as to move upward with the pressurized oil, and the upper surface of the third piston (19b) is brought into contact with the second working piston (18) and the second working piston (18). Is provided in contact with the lower surface of the second elevating member (14a), and a hydraulic pressure generator (25) for supplying pressure oil is provided in the third hydraulic chamber (19c) so that the lower mold (2) is moved downward. Pressurizing means to pressurize,
A second inner cylinder (20) is provided at the center of the second outer cylinder (19), and the lower counter punch (22) is pushed upward into the second inner cylinder (20). The piston (20a) is slidably accommodated up and down, the fourth hydraulic chamber (20b) that moves up the fourth piston (20a) is filled with pressure oil, and the drain to the tank (35) Providing a hydraulic pressure generating device (25) for performing back pressure application means for applying back pressure to the lower counter punch (22);
When the slide (6) descends, pressure oil is supplied to the first hydraulic chamber (11c) to move the first piston (11b) downward, and to the third hydraulic chamber (19c). Pressure oil is supplied and the third piston (19b) is moved upward, and the upper die (1) and the lower die (2) are pressurized in the vertical direction by the pressurizing means to thereby open the cavities (1a) and (2a). Both sides are closed, the second hydraulic chamber (12b) is filled with pressure oil to apply back pressure to the upper counter punch (8), and the fourth hydraulic chamber (20b) is filled with pressure oil. Then, back pressure is applied to the lower counter punch (22) to distribute the work (7) in the cavities (1a) and (2a) under pressure, and before the slide (6) is lifted, and before the cavity (1a ), (2a) when the work (7) is filled, the second hydraulic chamber (12b) and Serial fourth hydraulic chamber pressure oil in (20b) is drained to the tank (35), closed forging die apparatus that is characterized in that a configuration in which depressurized back pressure.

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