JP2000343297A - Frame of press machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a frame deformation quantity fixed and to suppress the variance of die heights due to variance in press working states by controlling a hydraulic cylinder arranged between a crown part and a bed part so as to equalize the loads applied to the left/right and front/rear of a frame in press working. SOLUTION: A hydraulic cylinder 19 is arranged between a crown 2 and a bed in parallel to a tie rod 5. Dies 17A, 17B, 17C are arranged to a slide 8 and a bolster 21, and works are successively subjected to press working. When the left side load of a split press in press working is P1 and the right side load is P2, a difference is generated between the load P1 and P2 depending on the condition in working. The left side of the crown 2 is pushed up with a load of T1 and the right side with T2, respectively, by the hydraulic cylinder 19. The pushing up loads of the crown 2 are controlled by the hydraulic cylinder 19 so as to satisfy P1+T1=P2+T2, thus, the loads applied to tie rods 5 are kept constant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frame of a press machine, and more particularly, to a frame of a press machine provided with a device for correcting deformation of the frame due to a press load.

[0002]

2. Description of the Related Art When an eccentric load is generated in a press work, a frame is deformed unevenly, a press slide is tilted, and a die height is changed. As a result, the accuracy of the parts to be pressed deteriorates and the life of the mold is shortened. Prior art relating to correction for a change in die height due to uneven deformation of the frame includes Japanese Utility Model Laid-Open No. Sho 60-5800 and Japanese Patent Laid-Open No. Hei 8-243798.

In Japanese Utility Model Application Laid-Open No. 60-5800, the interval between the opposed die sets at the bottom dead center is detected during the press operation, and the pressure oil in the cylinder provided on the tie rod nut seat is controlled based on the detected value. A device is disclosed that keeps a distance between opposed die sets at the bottom dead center, that is, a constant die height. Japanese Patent Application Laid-Open No. H8-243798 discloses an apparatus in which a tie rod nut is rotated by an external driving means to change the effective length of the tie rod, thereby adjusting a spring constant of the entire frame, and correcting a change in die height due to an eccentric load. ing.

[0004]

In a press operation requiring a large number of steps at the start of the press operation or immediately before the end of the press operation,
Since the workpiece may not exist in a part of the process, an eccentric load having a different press load is generated for each stroke of the press slide. In this case, a device that detects the die height and performs feedback control to keep the die height constant cannot cope with a change in the press load for each stroke. Further, even in a device having a mechanism for rotating a tie rod nut, since the effective length of the tie rod with respect to the eccentric load is set in advance, it is not possible to cope with a press load that changes every stroke of a continuously operated press slide. .

[0005] The present invention is a press operation requiring multiple steps,
An object of the present invention is to correct a change in die height due to a deformation of a frame without interrupting a pressing operation even when a workpiece does not exist in a part of a process.

[Means for Solving the Problems]

According to a first aspect of the present invention, in a press machine having a crown portion and a bed portion, a hydraulic cylinder provided between the crown portion and the bed portion, and the hydraulic cylinder is moved to the left and right of the frame and / or A frame for a press machine comprising a hydraulic circuit for controlling a hydraulic cylinder so that all loads applied before and after are equal.

In this invention, a split press load applied to each tie rod at the time of press work is calculated from a press load specified in advance, and the crown is pushed up by the hydraulic cylinder so that the load applied to each tie rod becomes equal. Apply a load to each tie rod. Therefore, since the load applied to each tie rod is constant regardless of the press load,
The amount of deformation of the frame can be kept constant. As a result, a change in die height in the pressing operation state is suppressed.

According to a second aspect of the present invention, there is provided a press machine having a frame in which a crown, a column, and a bed are fastened by a plurality of tie rods, a hydraulic cylinder provided on each tie rod nut seat, and a load and a size applied to each tie rod. A frame for a press machine comprising a hydraulic circuit for controlling a hydraulic cylinder so as to apply a load of the same direction but in the opposite direction to the crown.

In this invention, a divided press load applied to each tie rod is obtained by calculation from a press load specified in advance, and a load having the same magnitude but the opposite direction to the load applied to each tie rod is applied to the crown by the hydraulic cylinder,
Balance the load on the crown. Thereby, the deformation of the frame can be suppressed. As a result, a change in die height in the pressing operation state is suppressed.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2, which are the first embodiment of the present invention, a press machine 1 includes four tie rods 5 penetrating vertically through a crown 2, a column 3, and a bed 4.
And a tie rod nut 6 screwed to both ends of the tie rod 5
And has the frame 7 fastened with. A main motor 10 is provided above the crown 2, and a pulley 12 fixed to a drive shaft of the main motor 10 and a flywheel 9 are supported by a belt 13. A shaft 15 fixed to the flywheel 9 meshes with a drive mechanism (not shown) provided inside the crown 2, and the drive mechanism is connected to the slide 8 via a connection 14. The slide 8 is vertically movably guided by a slide guide 16 fixed to the column 3. The rotational force of the main motor 10 as a drive source is transmitted as a vertical movement of the slide 8 via a drive mechanism and a connecting part 14 by connecting / disconnecting a clutch brake 11 built in the flywheel 9.

A hydraulic cylinder 19 is provided between the crown 2 and the bed 4 in parallel with the tie rod 5. The center of the hydraulic cylinder 19 is located on an axis connecting the centers of the front and rear tie rods 5. When hydraulic pressure is applied to the hydraulic cylinder 19 by the hydraulic pump 20, the piston 18 of the hydraulic cylinder 19 can apply a force upward from the lower surface of the crown 2. The hydraulic cylinder 1
The load applied by 9 to the crown 2 is controlled to an arbitrary load by a control device (not shown).

On the other hand, the slide 8 and the bolster 21 are provided with dies 17A, 17B and 17C. The workpiece is transported by a transport device (not shown), and the press machine 1 processes the workpiece in the order of the dies 17A, 17B, and 18C.

Here, in order to explain the operation at the time of press working, the force by which the left hydraulic cylinder 19 pushes up the crown 2 is represented by T1, and the right is also represented by T2, and the press load is divided by the positions of the left and right hydraulic cylinders 19. The left side of the divided press load is represented by P1, and the right side is represented by P2. Here, for convenience, the hydraulic cylinder 19 and the mold 17A between the molds and adjacent ones
Alternatively, the dies 17C are arranged at equal pitches in the left-right direction, and the press loads applied to the dies 17A, 17B, and 17C are 40t, 40t, and 20t, respectively.

At the start of press work, etc., the work is
When processing is performed only with 7A, the pitch in the left-right direction between the dies and between the adjacent hydraulic cylinders 19 and the dies 17A or 17C is equal, so that P1: P2 = 3: 1. Therefore, the divided press load at the time of press working is P1 = 30t,
2 = 10t. Here, when the crown 2 is pushed up with the load of T1 = 25t and T2 = 45t by the hydraulic cylinder 19, the load applied to the tie rod 5 becomes a value obtained by adding P1 to T1 on the left side, and a value obtained by adding P2 to T2 on the right side. Both sides are 55t.

Next, the work is performed on all the dies 17A and 17A.
In the case of working at B and 17C, the split press load at the time of press working is P1 = 55t and P2 = 45t. Here, the crown 2 is moved by the hydraulic cylinder 19 so that T1 = 0t and T2 =
If the tie rod 5 is pushed up with a load of 10 t, the pressing load on the tie rod 5 becomes 55 t on both the left and right sides,
The value is the same as in the case of A.

As described above, by controlling the load by which the hydraulic cylinder 19 pushes up the crown 2 according to the magnitude of the split press load, the hydraulic cylinder 19 is applied to the tie rod 5 irrespective of the state of press working, that is, the magnitude of the split press load. The load is always kept constant. Therefore, the amount of deformation of the frame 7 can be kept constant regardless of the state of the press working.

In the above-described example, the left-right direction of the press machine 1 has been described. However, the front-rear direction can be similarly considered. The hydraulic cylinder 19 may be controlled by calculating the divided press load applied to the tie rod 5 even if the position of the hydraulic cylinder 19 is an inappropriate distance from the dies 17A, 17B, 17C.

Next, FIG. 3 shows a second embodiment of the present invention.
The press machine 1A shown here is the same as the press machine 1 shown in FIGS. 1 and 2 except that the hydraulic cylinder 19 is removed and the tie rod nut 6 on the crown 2 side is replaced with a hydraulic cylinder 22.

The hydraulic cylinder 22 is provided with a nut piston 22A screwed to the tie rod 5, and an oil chamber 22B is provided below the nut piston 22A. Pressure oil is supplied to the oil chamber 22B from the hydraulic pump 20, and a load is applied to the crown 2 downward. The load exerted on the crown 2 by the hydraulic cylinder 22 is controlled to an arbitrary load by a control device (not shown).

Here, in order to explain the operation at the time of press working, the force by which the left hydraulic cylinder 22 pushes down the crown 2 is represented by S1, and the right side is represented by S2, and the press load is represented by the position of the left and right hydraulic cylinders 22, that is, The left side of the divided press load divided at the position of the tie rod 5 is P1,
The right side is designated as P2. Here, for the sake of convenience, it is assumed that the horizontal pitch between the hydraulic cylinders 19 between the dies and between the adjacent hydraulic cylinders 19 and the dies 17A or 17C is arranged at an equal pitch.
The press load applied to 7A, 17B and 17C is 40 respectively.
t, 40t, and 20t.

At the start of press work, etc., the work is
In the case of machining only with 7A, the pitch in the left-right direction between the molds and between the adjacent hydraulic cylinders 22 and the mold 17A or the mold 17C is equal, so that P1: P2 = 3: 1. Therefore, the divided press load at the time of press working is P1 = 30t,
2 = 10t. Here, when a load of S1 = 30t and S2 = 10t is applied to the crown 2 by the hydraulic cylinder 22, S1, S2, P1, and P2 are loads of the same size but in opposite directions. Balance.

Next, when the work is performed on all the dies 17A and 17
In the case of working at B and 17C, the split press load at the time of press working is P1 = 55t and P2 = 45t. Here, S1 = 55t, S2
When a load of = 45 t is applied, S1, S2 and P1, P2 are loads of the same size and opposite directions, so the load on the crown 2 is entangled with the left and right, the same result as when the work is in the mold 17A. become.

As described above, if a load having the same magnitude as the split press load but in the opposite direction is applied to the crown 2 by the hydraulic cylinder 22, the load applied to the crown 2 is always balanced. Therefore, regardless of the state of the press working, the deformation of the frame 7 can be suppressed.

In the above-described example, the left-right direction of the press machine 1 has been described, but the same applies to the front-rear direction.

Although both the first and second embodiments of the present invention have shown the case where three dies are provided, the number of dies may be increased or decreased. When a combined eccentric load of front, rear, left and right is generated, the divided press load at that time is calculated, and a load corresponding to the divided press load is generated by the hydraulic cylinder, whereby the same effect as in the above-described embodiment can be obtained.

Further, both the first and second embodiments of the present invention can cope with the press load with respect to the press working height, that is, the press load that changes during one stroke of the press slide. In the press machine 1 or 1A, the same effect can be obtained if the press load corresponding to the working height is measured in advance or by a load meter and the hydraulic cylinder is controlled based on the press load in the same manner as in the above-described embodiment. Obtainable.

[0027]

According to the first aspect of the present invention, the load applied to each tie rod is constant irrespective of the press load, and the amount of deformation of the frame can be always constant. As a result, a change in die height due to a change in the press operation state can be suppressed.

According to the second aspect of the present invention, the load applied to the crown by the hydraulic cylinder and the press load are always balanced, and the deformation of the frame can be suppressed. As a result, it is possible to suppress a change in die height due to the pressing operation state.

[Brief description of the drawings]

FIG. 1 is an overall view of a press machine.

FIG. 2 is a sectional view taken along line AA of FIG. 1;

FIG. 3 is an overall view of a press machine.

[Explanation of symbols]

1 is a press machine, 2 is a crown, 3 is a column, 4 is a bed, 5 is a tie rod, 6 is a tie rod nut, 7 is a frame, 8 is a slide, 9 is a flywheel, 10 is a main motor, 11 is a clutch brake, 12 Is a pulley, 1
3 is a belt, 14 is a connecting part, 15 is a shaft, 16 is a slide guide, 17A, 17B, and 17C are dies, 18 is a piston, 19 is a hydraulic cylinder, 20 is a hydraulic pump,
1 is a bolster, 22 is a hydraulic cylinder, 22A is a nut piston, and 22B is an oil chamber.

Claims (2)

[Claims] In a press machine having a crown portion and a bed portion, a hydraulic cylinder provided between the crown portion and the bed portion and a load applied to the left and right and / or front and rear sides of the frame during the pressing operation are all applied to the hydraulic cylinder. A frame for a press machine, comprising a hydraulic circuit for controlling hydraulic cylinders to be equal. 2. A press machine having a frame in which a crown, a column, and a bed are fastened by a plurality of tie rods, wherein a hydraulic cylinder provided on each tie rod nut seat has the same load as the load applied to each tie rod and the direction is the same. A frame for a press machine comprising a hydraulic circuit for controlling a hydraulic cylinder so as to apply a reverse load to a crown.