Die device for forging

Abstract

Provided is a die device for forging, with which a workpiece can be sufficiently forged even when the press machine capacity required at the time of forging is low. A guide post 5 has a piston 8, the piston 8 is raisably / lowerably accommodated in a hydraulic barrel part 6 that is fixed to a base 1, and the guide post 5 demonstrates a tie rod function.

Description

Forging mold equipment

[0001] The present invention relates to a forging die device.

[0002] Conventionally, die apparatuses used for forging bevel gears, CVJ inner dies, tripods, spiders, etc. have been configured and operated as follows: Upper and lower dies are joined together to form a cavity, which is closed so as not to open during molding, and a punch is pressed into the die (cavity) while maintaining this closed state to perform molding (see, for example, Patent Document 1).

[0003] Patent No. 3466445

[0004] However, in conventional forging die devices, it is necessary to apply the sum of a load for closing the upper and lower dies and maintaining the closed state, and a load for pushing the forming punch (die), and there is a problem in that the forming press requires a capacity greater than the sum of these two loads. In particular, in the automotive industry, etc., with the recent shift to electric vehicles, molded products (parts) have become larger, and an increase in capital investment due to the upsizing (updating) of forming presses, etc. has become a problem.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a forging die apparatus that can solve these problems, avoid the need for a large-sized forming press, and efficiently produce formed products.

[0006] The present invention provides a forging die apparatus in which a die set installed between a lower base and an upper press ram of a press machine includes a first die holder having an upper die, a second die holder having a lower die, and a guide post that guides the first die holder up and down while holding the first die holder and the second die holder so that they do not shift position left and right, front and rear in a plan view; the guide post is connected to a piston that is housed in a hydraulic barrel fixed to the base and is capable of moving up and down; and the guide post is configured to function as a tie rod that brings the first die holder and the second die holder closer to each other.

[0007] Furthermore, the present invention is configured such that the tie rod function of the guide post causes the first die holder and the second die holder to approach each other, maintaining the upper die and the lower die in a closed state, and with the workpiece to be forged held by the lower die, the upper end of the forming pin maintains a state in which it protrudes from the upper surface of the first die holder; and the pressing force of the press ram pushes the upper end of the forming pin in the protruding state downward, completing the forging of the workpiece.

[0008] In the forging die device according to the present invention, the guide post functions as a tie rod using the piston in the hydraulic barrel. This tie rod function allows the upper and lower dies to be closed in a vertically pressed-contact state while maintaining the first and second die holders in close proximity to each other. Therefore, the load required to close the upper and lower dies in a pressed-contact state using the press (or its press ram) can be significantly reduced. Thus, the required capacity of the press is limited to the load required to push the forming pins necessary for forming the workpiece into the cavity. This prevents the press from becoming too large (high load), thereby avoiding higher costs.

[0009] It is a cross-sectional view of a main part in an open state, showing one embodiment of the present invention. It is a cross-sectional view of a main part showing a state during work formation. It is a cross-sectional view of a main part showing when work formation is completed. It is a hydraulic circuit diagram corresponding to the state of Figure 1. It is a hydraulic circuit diagram corresponding to the state of Figure 2. It is a hydraulic circuit diagram corresponding to the state of Figure 3.

[0010] The present invention will be described in detail below based on the illustrated embodiments. In Figures 1 to 3, P denotes a press machine, which comprises a lower base 1 and an upper press ram 2. A die set Ds (which is replaceable) is installed in the space between the base 1 and the press ram 2 of this press machine P.

[0011] The die set Ds includes an (upper) first die holder 3 having an upper die 11, a (lower) second die holder 4 having a lower die 12, and a guide post 5. The guide post 5 guides the first die holder 3 up and down while holding the first die holder 3 and the second die holder 4 so that they do not shift in position left and right, or front and rear, in a plan view.

[0012] Moreover, the guide post 5 is connected to a piston 8 housed in a hydraulic barrel portion 6 fixed to the base 1 so as to be movable up and down. Therefore, the guide post 5 functions as a tie rod that brings the first die holder 3 and the second die holder 4 closer to each other. This tie rod function applies a pressing force to the upper die 11 of the first die holder 3 against the lower die 12 of the second die holder 4, closing the upper die 11 and the lower die 12 and maintaining the closed state so that they do not open during subsequent molding.

[0013] It can be said that the hydraulic cylinder is made up of the hydraulic barrel 6, the piston 8, and the guide post 5 (as a piston rod). Usually, four guide posts 5 are provided, but it is preferable that all guide posts 5 have a structure including a piston 8 and a hydraulic barrel 6.

[0014] Due to the tie rod function of the guide post 5, the first die holder 3 and the second die holder 4 are brought close to each other (as shown in FIGS. 1 and 2), the upper die 11 and the lower die 12 are kept closed, and the workpiece W to be forged is held by the lower die 12. With this in mind, the upper end 10A of the forming pin 10 is kept protruding from the upper surface 3A of the first die holder 3 by a predetermined dimension ΔH (see FIG. 2).

[0015] 2 and 3, the press ram 2 applies a downward pressing force F2 to push the upper end 10A of the forming pin 10, which had been protruding upward, downward, completing the forging of the workpiece W (see FIG. 3). In FIGS. 1 to 3, a small-diameter punch pin 13 is provided at the lower end of the forming pin 10 in a protruding manner, which works in cooperation with the die pin 14 below to directly forge the workpiece W and plastically deform it into a predetermined shape.

[0016] A piston 17 is housed in the lower hydraulic chamber 16 and is capable of short vertical strokes, and as shown in Figures 2 and 3, this piston 17 causes the upper die 11 and lower die 12 to lower a small distance during forging, thereby ensuring reliable and high-precision forming of the workpiece W. The upper hydraulic chamber 18 contains the upper end of a piston 19 and is capable of short vertical strokes. When this piston 19 descends, the upper die 11 and lower die 12 descend (corresponding to the descent of the forming pins 10 and punch pins 13), as shown in Figures 2 and 3.

[0017] Next, Figures 4, 5, and 6 correspond to Figures 1, 2, and 3, respectively, and include the hydraulic circuit, hydraulic pumps 21, 21, and valves. Two sets of hydraulic pumps 21 and drive motors M are installed in Figures 4 to 6. Providing two sets allows the forging speed and other parameters to be selected according to the type, shape, size, and other factors of the workpiece.

[0018] Furthermore, a high-pressure oil supply / low-pressure oil discharge switching circuit L1 having an electromagnetic switching valve 22, a relief valve 23, etc. is provided to raise and lower the piston 8 inside the hydraulic barrel portion 6 and move the guide post 5 up and down. The relief valve 23 is added to this circuit L1. Furthermore, a high-pressure oil supply circuit L2 is provided, which branches off (at branch points 25, 25) from the discharge pipes 24, 24 of the hydraulic pumps 21, 21 to send high-pressure oil to the hydraulic chambers 16, 18 that house the pistons 17, 19.

[0019] This high-pressure oil supply circuit L2 branches at a branch point 28, one of which is connected to the hydraulic chamber 16 of the piston 17 via a branch pipe 29, and the other is connected to the hydraulic chamber 18 of the piston 19 via a branch pipe 30. Moreover, a check valve 31 and an electromagnetic ON-OFF switching valve 32 are interposed midway along the branch pipe 30. Furthermore, a return pipe 34 is disposed midway along the branch pipe 30, branching off to return the oil to a tank 33. Moreover, this return pipe 34 is provided with an electromagnetic ON-OFF switching valve 35, which is normally in the OFF state.

[0020] In the state shown in FIGS. 4 and 1, high-pressure oil discharged from the hydraulic pumps 21, 21 is sent via a switching valve 22 to the space below the piston 8 connected to the lower side of the guide post 5, pushing up the first die holder 3 and opening the upper die 11 and the lower die 12.

[0021] 5 and 2, the switching valve 22 is switched so that the high-pressure oil discharged from the hydraulic pumps 21, 21 is sent to the space above the piston 8 in the hydraulic barrel 6, moving the piston 8 and the guide post 5 downward, and lowering the first die holder 3 to close the upper die 11 and the lower die 12. At this time, the upper end 10A of the forming pin 10 protrudes from the upper surface 3A of the first die holder 3.

[0022] 6 and 3, the press ram 2 of the press P moves downward to press down the upper end 10A of the forming pin 10, and the work W can be forged.

[0023] As described above in detail, the present invention provides a forging die apparatus in which a die set Ds installed between the lower base 1 and the upper press ram 2 of a press P includes a first die holder 3 having an upper die 11, a second die holder 4 having a lower die 12, and a guide post 5 that guides the first die holder 3 up and down while holding the first die holder 3 and the second die holder 4 so that they do not shift left and right, front and rear in a plan view; the guide post 5 is connected to a piston 8 that is housed in a hydraulic barrel portion 6 fixed to the base 1 and is capable of moving up and down; and the guide post 5 is configured to function as a tie rod that moves the first die holder 3 and the second die holder 4 closer to each other. Therefore, it is sufficient for the press P to generate a pressing force sufficient to press the forming pins 10 against the workpiece W (a pressing force significantly smaller than conventional forces is sufficient), thereby significantly reducing the capital investment costs for the press P.

[0024] Furthermore, the tie rod function of the guide post 5 allows the first die holder 3 and the second die holder 4 to approach each other, maintaining the upper die 11 and the lower die 12 in a closed state, and with the workpiece W to be forged held by the lower die 12, the upper end 10A of the forming pin 10 remains protruding from the upper surface 3A of the first die holder 3; and the pressing force F2 of the press ram 2 presses the protruding upper end 10A of the forming pin 10 downward, completing the forging of the workpiece W. This configuration requires only minor modifications to the guide post 5, thereby reducing capital investment costs for increasing the capacity of the press P. Another advantage is that noise generated during the forging process can be reduced.

[0025] REFERENCE SIGNS LIST 1 Base 2 Press ram 3 First die holder 3A Upper surface 4 Second die holder 5 Guide post 6 Hydraulic barrel part 8 Piston 10 Forming pin 10A Upper end part 11 Upper die 12 Lower die Ds Die set F2 Pressing pressure P Press machine W Workpiece to be forged

Claims

1. A forging die device in which a die set (Ds) installed between a lower base (1) and an upper press ram (2) of a press machine (P) comprises a first die holder (3) having an upper die (11), a second die holder (4) having a lower die (12), and a guide post (5) that guides the first die holder (3) up and down while holding the first die holder (3) and the second die holder (4) so ​​that they do not shift left and right or front and rear in a plan view, wherein the guide post (5) is connected to a piston (8) housed in a hydraulic barrel section (6) fixed to the base (1) so as to be able to move up and down, and the guide post (5) is configured to function as a tie rod that brings the first die holder (3) and the second die holder (4) closer to each other.

2. A forging die device as set forth in claim 1, wherein the guide posts (5) function as tie rods to bring the first die holder (3) and the second die holder (4) close to each other, keeping the upper die (11) and the lower die (12) closed, and with the workpiece (W) held by the lower die (12), the upper end (10A) of the forming pin (10) is kept protruding from the upper surface (3A) of the first die holder (3), and the pressing force (F2) of the press ram (2) pushes the upper end (10A) of the forming pin (10) in the protruding state downward, completing the forging of the workpiece (W).

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