Lifter unit

Abstract

To propose a lifter unit which inhibits occurrence of twisting.SOLUTION: A lifter unit is attached to a die of a press working machine and includes: a base part fixed to a lower die of the die and having a main bush and an anti-rotation bush; an elastic body which is inserted into the base part and expands or contracts in a press direction of the press working machine; a lifter plate which is operated in the press direction by the elastic body expanding or contracting; one main shaft which is fixed to the lifter plate, supported slidably in the press direction by the base part through the main bush, and formed to guide the lifter plate in the press direction; and an anti-rotation shaft which is fixed to the lifter plate, supported slidably in the press direction by the base part through the anti-rotation bush, and formed to stop rotation of the lifter plate.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a lifter unit.

Background Art

[0002] A lifter unit is attached to a mold of a press working machine and is used for lifting up a workpiece after processing to convey the workpiece to the next process.

[0003] FIG. 4 shows a general lifter unit. As shown in FIG. 4, the lifter unit is a unit that lifts up a workpiece from a lower mold in order to carry out the workpiece molded by the mold to the next process.

[0004] Patent Document 1 describes a lifter device using one shaft and a rotation stopper as a driving means for lifting up.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In a general lifter unit, due to the adhesion of the molded workpiece to the mold, the overhang shape, and the asymmetry of the workpiece shape, even when simply lifting the workpiece, it is placed in a state where cocking is likely to occur due to uneven load.

[0007] As shown in FIG. 5, cocking means that when sliding occurs with an uneven load applied to the shaft, an uneven load is applied to the shaft and the bush, resulting in the vertical movement of the shaft stopping during sliding, or uneven wear due to the uneven load occurring on the shaft or the bush.

[0008] In the prior art lifter unit of Patent Document 1, the air cylinder performs the roles of a pressure source and a main shaft with one component. The load applied to the lifter plate is mainly received by the main shaft, but the air cylinder is a component for lifting and does not assume an eccentric load. Therefore, if an eccentric load is applied to the air cylinder repeatedly, it may affect the operation. Also, Patent Document 1 does not provide any suggestion on the situation where an eccentric load of the workpiece is applied to the lifter plate or on suppressing the occurrence of jamming.

[0009] The present invention has been made to solve such conventional problems and aims to suppress the occurrence of jamming.

Means for Solving the Problems

[0010] The lifter unit of the present invention is a lifter unit mounted on a die of a press working machine, and includes a base portion fixed to the lower die of the die and having a main bush and an anti-rotation bush, an elastic body inserted into the base portion and expanding and contracting in the press direction of the press working machine, a lifter plate that operates in the press direction due to the expansion and contraction of the elastic body, a main shaft fixed to the lifter plate and slidably supported in the press direction on the base portion via the main bush for guiding the lifter plate in the press direction, and an anti-rotation shaft fixed to the lifter plate and slidably supported in the press direction on the base portion via the anti-rotation bush for preventing the rotation of the lifter plate.

Effects of the Invention

[0011] According to the lifter unit of the present invention, the occurrence of jamming can be suppressed.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Mode for Carrying Out the Invention

[0013] Hereinafter, the lifter unit of the embodiment will be described in detail. Note that the present invention is not limited to this embodiment.

[0014] FIG. 1 is a diagram showing the lifter unit 1. FIG. 2 is a perspective view of the lifter unit 1. FIG. 3 is a sectional view taken along line A-A of FIG. 1 of the lifter unit 1 of the embodiment. As shown in FIGS. 1 to 3, the lifter unit 1 includes a base plate 2, a base block 3, a main bush 4, a rotation prevention bush 5, a coil spring 6, a lifter plate 7, a main shaft 8, a stopper 9, and a rotation prevention shaft 10. Note that the base plate 2 and the base block 3 are also collectively referred to as the base portion.

[0015] FIG. 7 is a diagram showing the clearance, shaft length, shaft diameter, bearing length, and bearing inner diameter of the lifter unit 1.

[0016] The base plate 2 is a rectangular parallelepiped member. The base plate 2 is fixed to a mold (not shown). The base plate 2 has a lower surface 2a, a pair of through holes 2b, a through hole 2c, a through hole 2d, a housing portion 2e, and a recessed portion 2f.

[0017] The through hole 2c is approximately at the center in the longitudinal direction of the base plate 2. The pair of through holes 2b are symmetrically arranged with the through hole 2c as the center. The through hole 2d and the recessed portion 2f are outside either one of the pair of through holes 2b toward the end face in the longitudinal direction of the base plate 2 with the through hole 2c as the center. The housing portion 2e is concentric with the through hole 2c. The cylindrical recessed portion 2f is concentric with the through hole 2d.

[0018] The pair of through holes 2b are insertion portions for the coil springs 6. The through hole 2c is an insertion portion for the main shaft 8. The through hole 2d is an insertion portion for the anti-rotation shaft 10.

[0019] The base block 3 is a rectangular parallelepiped member. The base block 3 has an upper surface 3a, a pair of cylindrical recessed portions 3b, a cylindrical recessed portion 3c, a through hole 3e, and a through hole 3d. The through hole 3e is approximately at the center in the longitudinal direction of the base block 3. The recessed portion 3c is concentric with the through hole 3e. The pair of recessed portions 3b are symmetrically arranged with the recessed portion 3c as the center. The through hole 3d is outside either one of the pair of recessed portions 3b toward the end face in the longitudinal direction of the base block 3 with the recessed portion 3c as the center.

[0020] The upper surface 3a is a contact surface with the lower surface 2a of the base plate 2. The pair of recessed portions 3b are assembly portions for the pair of coil springs 6. The recessed portion 3c is an assembly portion for the main bush 4. The through hole 3d is an insertion portion for the anti-rotation shaft 10.

[0021] The main bush 4 is a hollow cylindrical member and has a through hole 4a. One end of the main bush 4 is accommodated in the accommodating portion 2e of the base plate 2. The other end of the main bush 4 is accommodated in the recessed portion 3c of the base block 3. By accommodating the main bush 4 in the base plate 2 and the base block 4, it is used for positioning the base plate 2 and the base block 4.

[0022] The material of the main bush 4 is a copper alloy. The axial length of the main bush 4 is B1. A main shaft 8 is inserted into the main bush 4 (with a predetermined clearance Mc).

[0023] The anti-rotation bush 5 is a hollow cylindrical member and has a through hole 5a. The anti-rotation bush 5 is accommodated in the recessed portion 2f. The material of the anti-rotation bush 5 is a copper alloy. The length of the anti-rotation bush is B2. An anti-rotation shaft 10 is inserted into the through hole 5a (with a predetermined clearance Rc).

[0024] One end of a pair of coil springs 6 is accommodated in a pair of recessed portions 7b of a lifter plate 7 described later, and the other end is accommodated in a pair of recessed portions 3b.

[0025] A pair of coil springs 6 is accommodated in a pair of through holes 2b of the base plate 2. The pair of coil springs 6 pushes the lifter plate 7 upward by elastic force. Note that the number of coil springs 6 is not limited to two. Also, instead of a coil spring, a gas spring or the like may be used.

[0026] The lifter plate 7 is a rectangular parallelepiped member. The lifter plate 7 has an upper surface 7a, a pair of recessed portions 7b, a recessed portion 7c, and a recessed portion 7d. The upper surface 7a is an attachment portion of a shape block (not shown). The recessed portion 7c is approximately at the center in the longitudinal direction of the lifter plate 7. The pair of recessed portions 7b are at symmetric positions with the recessed portion 7c as the center. The recessed portion 7d is outside one of the pair of recessed portions 7b toward the end surface in the longitudinal direction of the lifter plate 7 with the recessed portion 7c as the center.

[0027] The main shaft 8 is a cylindrical member. The diameter of the main shaft 8 is ds. The axial length of the main shaft 8 is L1. The main shaft 8 is inserted into the main bush 4 (with a predetermined clearance Mc).

[0028] The upper end of the main shaft 8 is fixed to the recessed portion 7c of the lifter plate 7. A stopper 9 is attached to the lower end of the main shaft 8. The diameter of the main shaft 8 is ds. The axis C of the main shaft 8 is parallel to the pressing direction.

[0029] The anti-rotation shaft 10 is a cylindrical member. The diameter of the anti-rotation shaft 10 is dms. The axial length of the anti-rotation shaft is L2. The anti-rotation shaft 10 is inserted into the anti-rotation bush 5 (with a predetermined clearance Rc), and the upper end is fixed to the recessed portion 7d of the lifter plate 7. The axis D of the anti-rotation shaft 10 is parallel to the pressing direction.

[0030] The lifter unit 1 is interlocked with the operation of the upper die (not shown) in the pressing direction. The lifter unit 1 is fixed to the lower die (not shown), and includes a base block 3 having a main bush 4 and an anti-rotation bush 5, a coil spring 6 inserted into the base block 3 and expanding and contracting in the pressing direction, a lifter plate 7 operating in the pressing direction due to the expansion and contraction of the coil spring 6, a main shaft 8 fixed to the lifter plate 7 and slidably supported in the pressing direction on the base block 3 via the main bush 4 for guiding the lifter plate 7 in the pressing direction, and an anti-rotation shaft 10 fixed to the lifter plate 7 and slidably supported in the pressing direction on the base block 3 via the anti-rotation bush 5.

[0031] As shown in FIG. 9, the lifter unit 1 has a structure in which the lifter plate 7 is reciprocated in the pressing direction by two coil springs 6 and one main shaft 8, and the rotation of the lifter plate 7 (in the C direction and the D direction in the figure) is stopped by the anti-rotation shaft 10.

[0032] Figure 10 shows the lifter unit 1 with the shape block 11 attached. The shape block 11 has a panel processing part 11a. As shown in the figure, usually, in the molding of corrugated panels, the shape of the peak of the panel processing part 11a often differs between the left and right, the angle of the peak differs between the left and right, and many are asymmetric. That is, when molding an asymmetric panel, an eccentric load is generated on the mold due to the panel processing part 11a. The eccentric load generated on the mold is transmitted to the lifter plate, and an eccentric load is also generated on the lifter plate. Also, the main shaft 8 is preferably provided at the lower part of the panel processing part 11a in order to support the eccentric load.

[0033] Figure 5 is a schematic diagram explaining the occurrence of kinking in a general lifter unit. When an eccentric load is applied to the lifter plate, rotation and inclination occur. In order to support the load applied to the lifter plate, it is necessary to reduce the clearance between the shaft and the bush so that the shaft and the bush slide. However, when the clearance is reduced, when the shaft moves in the processing direction A and the return direction B in a state where an eccentric load is applied to the lifter plate, the shaft may contact the bush, and the vertical movement of the shaft may stop halfway, or eccentric wear may occur on the shaft and the bush.

[0034] As shown in Figure 6, generally, the kinking occurrence rate and the clearance are in a substantially proportional relationship. The cause of kinking is due to an increase in the clearance (gap) between the shaft and the bearing. When the clearance is large, the inclination of the shaft is allowed and kinking is likely to occur (Figure 5). Also, since the processing accuracy of the panel is also required, the clearance cannot be increased without limit.

[0035] Since the lifter plate is a rectangular part, it is common technical knowledge to support the shaft with two shafts in order to stably reciprocate in the vertical direction while maintaining parallelism. Also, the type of two guides requires processing accuracy. It is not realistic to manufacture the product by reducing both the processing accuracy and the clearance.

[0036] In order to achieve the required processing accuracy of the panel while suppressing the occurrence rate of cocking, the lifter unit 1 of the embodiment has a single main shaft 8.

[0037] The lifter unit 1 of the embodiment is a lifter unit 1 in which the occurrence rate of cocking is suppressed by having a single main shaft 8 and managing the clearance, shaft diameter, shaft length, and bearing length.

[0038] In addition, by adopting a single main shaft 8 structure, the assembly accuracy is improved, and it is possible to eliminate assembly defects that cause cocking.

[0039] As shown in FIG. 8, in a general two-shaft structure, when the clearance between the shafts is Mc, the center line of shaft 1 is S1, the center line of shaft 2 is S2, and the accuracy between S1 and S2 is Sp, in order to assemble without problems, the accuracy Sp between the two shafts needs to be maintained as Sp - Mc < SP < Sp + Mc. However, in reality, when Mc is several tens of μm, the accuracy Sp between the shafts also needs to be suppressed to that level, which is extremely difficult in practice.

[0040] In the lifter unit 1 of the embodiment, the shaft structure with a single main shaft 8 also makes assembly easier. FIG. 11 is a schematic diagram during assembly when there are two main shafts. In order to assemble the main shaft into the bush, in addition to the accuracy of the pitch between the shafts, the accuracy of the pitch between the bushes is also required. If the center lines of the two shafts pass through the center lines of the two bushes on the same straight line respectively, assembly can be carried out smoothly, but there may be cases where the allowable range of assembly is exceeded due to processing errors or assembly errors. If the allowable range is exceeded, the shaft cannot be assembled into the bush. Increasing the clearance will prevent non-assembly, but increasing the clearance will increase the occurrence rate of cocking.

[0041] FIG. 12 is a schematic diagram during assembly when the main shaft 8 of the embodiment is a single one. The main shaft 8 and the anti-rotation shaft 10 share roles. By sharing the roles of the main shaft 8 and the anti-rotation shaft 10, the accuracy Sp between the shafts is no longer required, and the machining becomes easier. Further, by making the length of the anti-rotation shaft 10 shorter than that of the main shaft 8, it is possible to prevent the assembly of the anti-rotation shaft 10 and the anti-rotation bush 5 from starting until the main shaft 8 and the main bush 4 are sufficiently assembled. Even if the clearance between the main shaft 8 and the main bush 4 is reduced, there is nothing to interfere with the assembly, so it can be easily assembled.

[0042] In the lifter unit 1, when the following conditions are satisfied, the occurrence of kinking can be more effectively suppressed.

[0043] The diameter dms of the anti-rotation shaft 10 is preferably smaller than the diameter ds of the main shaft 8, and the clearance Rc between the anti-rotation shaft 10 and the anti-rotation bush 5 is preferably larger than the clearance Mc between the main shaft 8 and the main bush 4. By setting dms < ds and Mc < Rc, when the main shaft 8 is inserted into the main bush 4, the anti-rotation shaft 10 and the anti-rotation bush 5 do not interfere, and the assembly can be performed more smoothly.

[0044] The length L1 of the main shaft 8 is preferably longer than the length L2 of the anti-rotation shaft 10, and the length B1 of the main bush 4 is preferably longer than the length B2 of the anti-rotation bush 5. By setting L2 < L1 and B2 < B1, after the main shaft 8 is inserted into the main bush 4 during assembly, the anti-rotation shaft 10 is inserted into the anti-rotation bush 5, so the assembly can be performed more smoothly. Since the anti-rotation bush 5 is not a part for sliding with the anti-rotation shaft 10 but a part for preventing rotation of the lifter plate 7, the length B2 of the anti-rotation bush 5 can be made shorter than the length B1 of the main bush 4. By assembling a bush with B2 shorter than B1, the parts cost of the product can be suppressed.

[0045] The lifter unit 1 of the embodiment has a main shaft 8 and a detent shaft 10. By making the clearance Rc between the detent shaft 10 and the detent bush 5 larger than the clearance Mc between the main shaft 8 and the main bush 4, the occurrence of jamming is reduced.

[0046] As shown in Fig. 6, the jamming occurrence rate and the clearance are approximately in a proportional relationship. Therefore, if the clearance is reduced, the jamming is in the direction of being eliminated. However, in the case of two general shafts of the lifter unit, interference occurs between each other and actually cannot be reduced properly.

[0047] The lifter unit 1 of the embodiment has one main shaft 8. By making the clearance Mc between the main shaft 8 and the main bush 4 smaller than the clearance Rc between the detent shaft 10 and the detent bush 5, the play of the device itself is eliminated, and the other detent shaft 10 is only used for the detent function, so that the occurrence of jamming can be kept low.

[0048] The diameter of the detent shaft 10 is preferably 10 mm or more and 30 mm or less. The diameter of the main shaft 8 is preferably 30 mm or more and 60 mm or less. The length of the detent shaft 10 is preferably 80 mm or more and 125 mm or less. The length of the main shaft 8 is preferably 125 mm or more and 200 mm or less. The length of the detent bush 5 is preferably 10 mm or more and 20 mm or less. The length of the main bush 4 is preferably 60 mm or more and 100 mm or less.

[0049] The clearance Mc is preferably 0.01 mm or more and 0.4 mm or less. The clearance Rc is preferably 0.2 mm or more and 2.0 mm or less (and Mc < Rc).

Example

[0050] Hereinafter, embodiments of the present invention will be described. Note that the present invention is not limited to the following embodiments.

[0051] The examples and comparative examples are shown in Table 1 below. In the examples, evaluation was performed in terms of the warpage rate (%). The warpage rate is the number of warpage occurrences shown as (%) when a lifter unit is incorporated into a press die under predetermined conditions and 100,000 shots are carried out.

[0052] [Table 1]

[0053] From the above results, it was demonstrated that the lifter unit of the example had extremely low warpage rates of 1 to 3% and excellent characteristics. On the other hand, general lifter units had warpage rates of 22 and 25%, showing high warpage rates.

[0054] As described above, the embodiments have been explained. However, this embodiment is presented as an example and is not intended to limit the scope of the invention. This novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. This embodiment and its modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and its equivalent scope.

Explanation of Reference Numerals

[0055] 1: Lifter unit, 2: Base plate, 3: Base block, 4: Main bushing, 5: Anti-rotation bushing, 6: Coil spring, 7: Lifter plate, 8: Main shaft, 9: Stopper, 10: Anti-rotation shaft, 11: Shape block

Claims

1. A lifter unit attached to a die of a press working machine, comprising: a base portion fixed to the lower die of the die and having a main bush and an anti-rotation bush; an elastic body inserted into the base portion and expanding and contracting in the press direction of the press working machine; a lifter plate that operates in the press direction by the expansion and contraction of the elastic body; a main shaft fixed to the lifter plate and slidably supported in the press direction on the base portion via the main bush for guiding the lifter plate in the press direction; an anti-rotation shaft fixed to the lifter plate and slidably supported in the press direction on the base portion via the anti-rotation bush for preventing rotation of the lifter plate; A lifter unit having the above components.

2. The lifter unit according to claim 1, wherein the diameter of the anti-rotation shaft is smaller than the diameter of the main shaft.

3. The lifter unit according to claim 1, wherein the clearance between the anti-rotation shaft and the anti-rotation bush is larger than the clearance between the main shaft and the main bush.

4. The lifter unit according to claim 1, wherein the length of the main shaft is longer than the length of the anti-rotation shaft.

5. The lifter unit according to claim 1, wherein the length of the main bush is longer than the length of the anti-rotation bush.

6. The lifter unit according to claim 1, wherein the elastic body is a coil spring or a gas spring.

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