JP7672138B2 - Press processing equipment - Google Patents

Description

The present invention relates to a press processing device that forms metal into a specified shape.

When compressing metals using press processing equipment, the effects of friction become significant for workpieces with low aspect ratio cross sections, where the thickness in the direction of pressure is thin relative to the area of pressure applied, and large compression loads are required. Possible ways to reduce the compression load are (1) reducing the friction between the tool and workpiece, (2) reducing the contact area of the tool, and (3) reducing deformation resistance. The following measures have been attempted for each of (1) to (3):

(1) By improving the performance of the lubricant and by applying vibration during pressure application to prevent the lubricant film from breaking (see Non-Patent Document 1), friction is reduced and the increase in load due to compression is reduced.
(2) The contact area is reduced by sequentially applying pressure using small tools, as in the case of swordsmiths, or by adopting rotary forging (see Non-Patent Document 2), in which a workpiece 101 is pressed down while a pressure platen 100 is rotated, as shown in Fig. 7. Patent Document 1 describes multi-oscillating pressure, in which a pressure platen (slide block) is supported at multiple points by multiple linear actuators to reduce the contact area by flexible inclined pressure.
(3) Non-Patent Document 3 suggests that the stress required to pressurize the workpiece 102 decreases under the combined stress of compression and shear, as shown in Figures 8(A) and (B), and describes torsional load forging, which reduces the compressive load by applying pressure while twisting.

JP 2019-155443 A

Tomomi Maeno, Kozo Osakada, Kenichiro Mori: "Reduction of Friction in Plate Forging by Load Vibration", Journal of the Japan Society for Technology of Plasticity, "Plasticity and Processing", Vol. 50-No. 585 (2009-10), pp. 951-955 Nozomi Kawai: New Edition of Plastic Processing Science, (1988), p. 139, Asakura Publishing Ryo Matsumoto, Hiroshi Yasuhito, and Yutaka Utsunomiya: "Reduction of axial load in cold upset compression by adding torsion", Proceedings of the 67th Joint Conference on Plastic Technology, (2016), pp. 85-86

However, in methods (1) and (3), the contact area between the press processing device and the workpiece cannot be reduced, and therefore the thinner the thickness in the pressure direction is relative to the pressure area, the greater the frictional force, making it difficult to reduce the compressive load. In addition, in rotary forging (2) and torsional load forging (3), the use of rotational motion limits the range of application for machining into axially symmetrical shapes. Moreover, in torsional load forging, as shown by the deformation of the specific region depicted by the virtual lines in Figures 8 (A) and (B), the acting shear stress is smaller on the radially inner side than on the radially outer side, so sufficient shear stress cannot be applied near the center of rotation.

In contrast, in the case of (2) multi-oscillating pressure, there is no restriction that the processed shape is limited to axial symmetry, but since the pressing surface is inclined during processing, there is a tendency for inclination to remain on the end surface of the processed workpiece.
The present invention has been made in consideration of the above circumstances, and aims to provide a press processing device that can prevent inclination from remaining on the end face of the workpiece while suppressing the compressive load and can handle the processing of various shapes.

The press processing device of the present invention, which is in line with the above-mentioned objective, is a press processing device that moves a first die in the P direction to approach a second die and compression molds a workpiece arranged between the first and second dies, and is equipped with a linear motion mechanism E that reciprocates one of the first and second dies in a direction perpendicular to the P direction, and a linear motion mechanism F that reciprocates one of the first and second dies in a direction perpendicular to the P direction and in a direction different from the direction of reciprocation by the linear motion mechanism E.

The press processing device according to the present invention is equipped with a linear motion mechanism E that reciprocates either the first or second die in a direction perpendicular to the P direction, and a linear motion mechanism F that reciprocates either the first or second die in a direction perpendicular to the P direction and in a direction different from the direction of reciprocation by the linear motion mechanism E. Therefore, the workpiece can be compression molded while either or both of the first and second dies are reciprocated in a direction perpendicular to the P direction, and the compression load during compression molding can be suppressed while preventing inclination of the end face of the processed workpiece.

1 is an explanatory diagram of a press working device according to an embodiment of the present invention; FIG. 11 is an explanatory diagram showing the movement of a lower mold. FIG. 1 is an explanatory diagram of an experimental machine used to measure compressive load. 13 is a graph showing the results of an experiment on reducing a compression load by reciprocating a lower die. 13 is a graph showing the results of an experiment on the effect of the reciprocating speed of the lower die on the load reduction rate. FIG. 13 is an explanatory diagram of a press working device according to a modified example. FIG. 1 is an explanatory diagram of rotary forging according to a first conventional example. 11A and 11B are explanatory views showing the state of compression processing by torsional load forging according to a second conventional example.

Next, with reference to the attached drawings, an embodiment of the present invention will be described for understanding the present invention.
As shown in Fig. 1, a press working apparatus 10 according to an embodiment of the present invention is an apparatus that moves an upper die (an example of a first die) 11 in a vertical direction (an example of a P direction) to approach a lower die (an example of a second die) 12, and compression-moldes a workpiece W disposed between the upper die 11 and the lower die 12. A detailed description will be given below.

As shown in FIG. 1, the press processing device 10 includes an oil-free slide plate 14 fixed on a base table 13, a lower die 12 placed on the slide plate 14, and an upper die 11 fixed to a movable table 15 provided above the lower die 12. The slide plate 14 has a copper alloy plate having a rectangular shape (including a square, the same applies to the following rectangles) in plan view with a number of holes (not shown) formed on one side, and solid lubricant embedded in each hole. The slide plate 14 has the side with the holes formed on the upper side, and the other side arranged on the lower side is fixed to the base table 13. The lower die 12 is a rectangular metal plate in plan view, and is placed on one side of the slide plate 14 in a state where it can move horizontally.

The lower ends of a plurality of guide members 16, 16a (two in this embodiment) each long in the vertical direction are fixed to the base table 13. A plate-shaped movable table 15 is attached to each of the guide members 16, 16a so as to be movable up and down while being horizontally disposed at a position spaced apart from the base table 13. The upper mold 11, which is a rectangular metal plate in a plan view, is fixed to the underside of the movable table 15 at a position above the lower mold 12 at a distance from the lower mold 12.
The movable table 15 is pushed down (moved in the P direction) by a hydraulic cylinder (not shown) and descends together with the upper die 11, vertically compressing the metal workpiece W sandwiched between the upper die 11 and the lower die 12. The lower die 12 is provided so as not to move in a direction approaching the upper die 11.

As shown in Figures 1 and 2, an electric cylinder 19 (one example of a linear motion mechanism E) having a movable rod 18 is attached to the support member 17 on which a portion of the base stand 13 is placed. The axis of the movable rod 18 is arranged horizontally, and the electric cylinder 19 moves the movable rod 18 horizontally at the height position of the lower mold 12. A linear guide 21 to which a slider 20 is movably attached is connected to the tip of the movable rod 18. The linear guide 21 has a pair of rails 22, 23 arranged in parallel, and the slider 20 can reciprocate horizontally along the rails 22, 23. The movable rod 18 moves forward and backward in a direction perpendicular to the direction in which the slider 20 reciprocates.

Similarly, an electric cylinder 26 (an example of a linear motion mechanism F) having a movable rod 25 is attached to the support member 24 on which the base stand 13 is partially placed. The axis of the movable rod 25 is arranged horizontally, and the electric cylinder 26 moves the movable rod 25 horizontally back and forth at the height position of the lower mold 12. A linear guide 28 to which a slider 27 is movably attached is connected to the tip of the movable rod 25. The linear guide 28 has a pair of rails 29, 30 arranged in parallel, and the slider 27 can reciprocate horizontally along the rails 29, 30.

The movable rod 25 advances and retreats in a direction perpendicular to the direction in which the slider 27 reciprocates and the direction in which the movable rod 18 advances and retreats. The extension direction of the rails 29, 30 is perpendicular to the extension direction of the rails 22, 23, and the slider 27 reciprocates in a direction perpendicular to the direction in which the slider 20 reciprocates. In this embodiment, the movable rods 18, 25 advance and retreat in increments of 1 to 10 μm.
The slider 20 is connected to one side wall portion (hereinafter referred to as the "first side wall portion") of the lower mold 12 having four side wall portions, and the slider 27 is connected to a second side wall portion that is adjacent to and perpendicular to the first side wall portion of the lower mold 12.

The lower mold 12 reciprocates in the advancing/retreating direction of the movable rod 18 (horizontal direction) when the movable rod 18 advances and retreats while the movable rod 25 is stopped, and reciprocates in the advancing/retreating direction of the movable rod 25 (horizontal direction, perpendicular to the advancing/retreating direction of the movable rod 18) when the movable rod 25 advances and retreats while the movable rod 18 is stopped. Thus, the electric cylinder 19 can reciprocate the lower mold 12 in a direction perpendicular to the P direction, and the electric cylinder 26 can reciprocate the lower mold 12 in a direction perpendicular to the P direction and in a direction different from the direction of reciprocation by the electric cylinder 19.

Here, since the direction of reciprocating movement of the lower die 12 by operation of the electric cylinder 19 and the direction of reciprocating movement of the lower die 12 by operation of the electric cylinder 26 are non-parallel, the lower die 12 can be moved in either direction along the imaginary horizontal plane by combining the forward and backward movements of the movable rods 18 and 25. For example, the lower die 12 can be rotated, or the lower die 12 can be reciprocated in a direction non-parallel to the forward and backward directions of the movable rods 18 and 25. Therefore, it is possible to realize appropriate movement of the lower die 12 according to the target shape after machining of the workpiece W.

In this embodiment, the direction of reciprocating movement of the lower die 12 by the operation of the electric cylinder 19 is perpendicular to the direction of reciprocating movement of the lower die 12 by the electric cylinder 26, so it is easy to control each of the electric cylinders 19, 26 (control of the advance/retract length, advance/retract timing, advance/retract speed, etc. of each of the movable rods 18, 25) to cause the lower die 12 to perform a specified operation.

Next, an experiment conducted to confirm the effects of the present invention will be described. In the experiment, as shown in FIG. 3, an experimental machine 37 was used, which has an electric cylinder (linear mechanism) 34 in which a movable rod 32 is connected to a lower die (second die) 33, and a movable table 36 to which an upper die (first die) 35 arranged above the lower die 33 is fixed. The axis of the movable rod 32 is arranged horizontally, and the movable rod 32 and the lower die 33 advance and retreat horizontally along the axis of the movable rod 32. The lower die 33 is placed on a roller-type bearing block 39 fixed to a base table 38, and the frictional force generated between the lower die 33 and the bearing block 39 when the lower die 33 advances and retreats is suppressed.

The movable table 36 is pushed down by an electric cylinder (not shown) to compress and mold the workpiece W' made of soft aluminum material placed between the upper die 35 and the lower die 33. The workpiece W' was cylindrical with a diameter of 6 mm and a height of 12 mm. In the experiment, the workpiece W' was compressed 3 mm in the axial direction while the upper end (area 3 mm in the axial direction) and lower end (area 3 mm in the axial direction) of the workpiece W' were restrained by the upper die 35 and the lower die 33, respectively. The advancement and retreat width (amplitude) of the movable rod 32 was 75 μm. A load cell was installed between the movable table 36 and the hydraulic cylinder to measure the compression load.

First, the compression load was continuously measured in each of the following cases (Case 1): (1) the workpiece W' was compressed by 3 mm with the movable rod 32 stationary, and (Case 2) the workpiece W' was compressed by 1.5 mm with the movable rod 32 stationary, and then the movable rod 32 was moved back and forth continuously to compress the workpiece W' by a further 1.5 mm (a total compression of 3 mm) (first experiment).
The measurement results are shown in Figure 4. In Figure 4, the horizontal axis indicates the amount of compression of the workpiece W', and the vertical axis indicates the compressive load. From the measurement results, it was confirmed that the compressive load could be reduced by the continuous forward and backward movement of the movable rod 32 (lower die 33). Furthermore, no inclination occurred on the upper and lower surfaces of the workpiece W' after processing.

Next, the compression load in case 2 was measured by changing the moving speed of the movable rod 32 to determine the effect of the moving speed of the movable rod 32 on the load reduction rate (second experiment). The results of the second experiment are shown in Figure 5. Here, as shown in Figure 4, the compression loads at the time when the workpiece W' is compressed by 3 mm in cases 1 and 2 are F and F', respectively, and F-F' = ΔF, so the load reduction rate is ΔF/F. In Figure 5, "U" in the "orthogonal speed ratio U/V" indicates the moving speed of the movable rod 32, and "V" indicates the descending speed of the upper die 35 pressed down by the hydraulic cylinder.

In addition, in the second experiment, a comparison was made between the actual measurement results (actual measurement results) and the analysis results by FEM (finite element method). From the actual measurement results and the analysis results by FEM shown in Figure 5, it was confirmed that the tendency of the actual measurement results is similar to the tendency of the analysis results by FEM, that the load reduction rate increases as the orthogonal speed ratio increases (the forward and backward speed of the movable rod 32 increases), that the increase in the load reduction rate with the increase in the orthogonal speed ratio becomes significant when the orthogonal speed ratio is 5 or less, and that the increase in the load reduction rate with the increase in the orthogonal speed ratio slows down when the orthogonal speed ratio exceeds 5.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above-mentioned embodiment, and all changes in conditions that do not depart from the gist of the present invention are within the scope of application of the present invention.
For example, the first and second dies do not have to be upper and lower dies, respectively, and the first and second dies may be disposed at the same height with a certain distance between them. In this case, the moving direction of the first die (direction P) is horizontal.
In addition, the second mold may be made movable in the opposite direction to the P direction (the direction in which the first mold is arranged), and when the first mold is moved in the P direction, the second mold may be moved in the opposite direction to the P direction to bring the first and second molds closer to each other.

In addition, both linear motion mechanisms E and F may reciprocate the first die, or one of linear motion mechanisms E and F may reciprocate an upper die, which is an example of a first die, and the other may reciprocate a lower die, which is an example of a second die. For example, the press processing device 40 shown in FIG. 6 is designed so that an electric cylinder 41, which is an example of a linear motion mechanism E, reciprocates a lower die 42, which is an example of a second die, and an electric cylinder 43, which is an example of a linear motion mechanism F, reciprocates an upper die 44, which is an example of a first die. The lower die 42 and the upper die 44 are provided in contact with bearing blocks 45 and 46, respectively, to suppress the generation of frictional force during reciprocation. W" is the workpiece.

Here, when the first and second dies are the upper die and the lower die, respectively, and the upper die is designed to be movable in the P direction while the lower die is not designed to move in a direction approaching the upper die (the opposite direction to the P direction), it is preferable to design the lower die so that both linear motion mechanisms E and F reciprocate, as in the above-mentioned press working device 10. This is because, when the upper die, which moves in the P direction, is reciprocated by the linear motion mechanism E, a moment due to the weight of the linear motion mechanism E is applied to the upper die as an eccentric load (this also applies to the linear motion mechanism F).
Furthermore, when both linear motion mechanisms E and F are adapted to reciprocate the lower die, the design can be simplified compared to when one of linear motion mechanisms E and F reciprocates the upper die and the other reciprocates the lower die.

10: Press processing device, 11: Upper die, 12: Lower die, 13: Base table, 14: Slide plate, 15: Movable table, 16, 16a: Guide member, 17: Support member, 18: Movable rod, 19: Electric cylinder, 20: Slider, 21: Linear guide, 22, 23: Rail, 24: Support member, 25: Movable rod, 26: Electric cylinder, 27: Slider, 28: Linear guide, 29, 30: Rail, 32: Movable rod, 33: Lower die, 34: Electric cylinder, 35: Upper die, 36: Movable table, 37: Experimental machine, 38: Base table, 39: Bearing block, 40: Press processing device, 41: Electric cylinder, 42: Lower die, 43: Electric cylinder, 44: Upper die, 45, 46: Bearing block, W, W', W": Workpiece

Claims (3)

A press working apparatus for compression-molding a workpiece disposed between a first die and a second die by moving a first die in a direction P so as to approach the second die,
a linear motion mechanism E that reciprocates either the first or second mold in a direction perpendicular to the P direction;
a linear motion mechanism F that reciprocates either the first or second die in a direction perpendicular to the P direction and in a direction different from the direction of reciprocation by the linear motion mechanism E. In the press processing device according to claim 1, the first and second dies are an upper die and a lower die, respectively, the lower die does not move in a direction approaching the upper die, and both of the linear motion mechanisms E and F reciprocate the lower die. The press working device according to claim 1 or 2, characterized in that the direction of reciprocating motion by the linear motion mechanism E is perpendicular to the direction of reciprocating motion by the linear motion mechanism F.

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