JPH10113797A - Auxiliary lift device of press die cushion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the auxiliary lift device of the press die cushion inexpensive by making a hydraulic pressure of an upper chamber flow out by a specific amount after locking a die cushion pad on the upper chamber side of a locking cylinder, and connecting an auxiliary lift cylinder lifting the die cushion pad as an auxiliary. SOLUTION: In the press die cushion with a cushion cylinder 2 supporting elastically the die cushion pad 1a, the locking cylinder 3 locking the die cushion pad 1a in a lowering position and a locking valve 4, after locking the die cushion pad 1a on the upper chamber 31 side of the locking cylinder 3, by making the hydraulic pressure of the upper chamber 31 flow out by a specific amount, the auxiliary lift cylinder 6 making the die cushion pad 1a lift as an auxiliary, is connected. Sine the auxiliary lift of the die cushion pad 1a can be performed without requiring servo valve, servocontroller, etc., the inexpensive auxiliary lift device can be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an auxiliary lift device for a press die cushion which enables an auxiliary lift of a die cushion pad with a simple device.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Publication No.
The device described in -65420 is known. The apparatus disclosed in the above-mentioned publication, after plastically working a work held between an upper die and a blank holder that can be raised and lowered, between the upper die and the lower die, temporarily stops the raising of the blank holder when the upper die is raised, A temporary stopping means for holding the blank holder at the lower limit position, and a pushing means for pushing up the work by a predetermined amount when the blank holder is at the lower limit position in the blank holder, and waiting for the blank holder to rise. Since the work can be accurately unloaded by the transfer means, the time required for unloading the work after the plastic working of the work is reduced, and the processing time can be shortened as a whole.

[0003]

However, in the above-mentioned conventional apparatus, since a small push-up means must be provided in the blank holder, the structure of the blank holder becomes complicated, and the push-up means is provided for each blank holder. Because of the necessity, there is a problem that the mold is expensive. In addition, since the work is auxiliary lifted by the lifting means at the same time as the upper mold is lifted after the molding is completed, there is a problem that the work comes into contact with the upper mold and the surface of the work is scratched.

On the other hand, in Japanese Utility Model Laid-Open No. 2-28396,
A die cushion device in which an auxiliary lift device is provided in a die cushion cylinder has been proposed. However, in the die cushion device described in the above publication, since the control of the die cushion cylinder is performed by a servo valve, an expensive servo valve and the The entire device becomes expensive because a servo controller or the like is required. The present invention has been made in order to improve such a conventional problem, and an object of the present invention is to provide an inexpensive press die cushion auxiliary lift device that enables an auxiliary lift of a die cushion pad using a simple device. Is what you do.

[0005]

In order to achieve the above object, the invention according to claim 1 comprises a cushion cylinder for elastically supporting a dicing pad, a locking cylinder for locking the die cushion pad to a lowered position, and In the press die cushion having a locking valve, an auxiliary lift cylinder for auxiliary lifting of the die cushion pad is connected to the upper chamber side of the locking cylinder by discharging a predetermined amount of hydraulic pressure in the upper chamber after locking of the die cushion pad. It was done.

With the above structure, the die cushion pad is locked to the lowered position by the locking cylinder upon completion of the molding of the workpiece, and then the hydraulic pressure in the upper chamber of the locking cylinder flows out to the auxiliary cylinder as the upper die rises. , The die cushion pad is assisted by a predetermined amount. As a result, the workpiece lifted by the auxiliary lift is held and transported by the workpiece transport means, so that the workpiece can be transported reliably, and the auxiliary lift can be performed without the need for a servo valve or a servo controller for controlling the workpiece. The lift device can be provided at a low cost with a simple configuration.

Further, since the auxiliary lift is performed immediately after the upper mold is lifted, there is no problem such as the work being damaged by the upper die as compared with the conventional case where the auxiliary lift is performed simultaneously with the upper mold lift.

In order to achieve the above object, according to the second aspect of the present invention, a plurality of auxiliary lift cylinders are connected in parallel so that the amount of auxiliary lift can be adjusted in a plurality of stages.

With the above configuration, the amount of auxiliary lift can be adjusted in a plurality of stages according to the size and shape of the work.
Even if the shape and size of the work change, the work can be transported reliably.

In order to achieve the above object, according to a third aspect of the present invention, an auxiliary lift cylinder is provided with a stroke adjusting means for adjusting a stroke of a piston so that an auxiliary lift amount can be adjusted steplessly. .

With the above configuration, the height of the auxiliary lift can be continuously adjusted according to the size and shape of the work.
Even if the size or shape of the work changes, the work can be transported more reliably.

In order to achieve the above object, according to the present invention, damper means is connected to the auxiliary lift cylinder, and the piston is stroked by the damper means after the auxiliary lift.

According to the above configuration, the responsiveness of the auxiliary lift cylinder is improved, and the need for a solenoid valve for controlling the auxiliary lift cylinder is eliminated, so that the hydraulic circuit can be configured at low cost.

[0014]

Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a circuit diagram showing an auxiliary lift device for a press die cushion, and FIG.

In FIG. 1, reference numeral 1 denotes a die cushion main body, a die cushion pad 1a for supporting a part of a lower mold (both not shown) from below through a cushion pin;
The die consists of a locking cylinder 3 for locking the cushion cylinder 2 and the die cushion pad 1a cushion pad 1a is elastically supported at the lower limit position, opened and closed by a pilot air between the upper locking cylinder 3 chamber 3 ₁ and the lower chamber 3 ₂ The locking valve 4 is connected.

Further the conduit 5 that connects the upper chamber 3 ₁ of this locking valve 4 and the locking cylinder 3, the auxiliary lift cylinder 6 constituting the locking device of the present invention is connected through the logic valve 7. The auxiliary lifting cylinder 6 by a piston 6a 2 chambers of the hydraulic chamber 6 _1, 6 ₂
Have been sectioning, the one hydraulic chamber ₆₁ and the locking upper chamber 3 ₁ of the cylinder 3 is connected via a logic valve 7, the other hydraulic chamber 6 ₂ two logic valves 8, the 9
Is connected. Therefore, the logic valves 8 and 9 and the logic valve 7 are controlled to open and close by pilot hydraulic pressure supplied via solenoid valves 11, 12 and 10.

In FIG. 1, LS ₁ and LS ₂ are limit switches operated by a piston rod 6b projected from the auxiliary lift cylinder 6, the limit switch LS ₁ is a forward end of the piston 6a, and the limit switch LS ₂ is The reverse end of the piston 6a is detected.

Next, the operation of the above-configured auxiliary lift device will be described with reference to FIG. When the upper die attached to the slide of the press (not shown) descends, comes into contact with the work on the lower die, and starts forming the work between the upper die and the lower die, the die cushion pad 1a is moved through the cushion pin. The descent is also started.

At this time, the solenoid valve 10 is in the position a, the solenoid valve 11 is in the position c, and the solenoid valve 12 is in the position e, the logic valve 7 is closed, the logic valve 8 is closed, the logic valve 9 is closed, and the logic valve is closed. since already operating oil through the valve 8 it is flowed from conduit 13 to the hydraulic chamber 6 _second auxiliary lift cylinder 6, the piston 6a of the auxiliary lift cylinder 6
Is stopped at the forward end.

Next, when the slide reaches the bottom dead center and the molding of the work is completed, the upper die starts to rise together with the slide.
Is closed, the die cushion pad 1a is locked at that position (lower limit position), and only the upper die rises.

[0021] Thereafter the logic valve 7 the solenoid valve 10 is switched to the position b is opened, at the same time when the electromagnetic valve 12 is logic valve 9 is switched to the position f is opened, the locking cylinder 3 the upper chamber 3 in ₁ hydraulic pressure flows through the logic valve 7 into the hydraulic chamber ₆₁ of the secondary lifting cylinder 6, since the oil pressure chamber 6 ₂ hydraulic pressure is drained from the logic valve 9, the oil of the upper chamber 3 ₁ auxiliary lift locking cylinders 3 reduced by the hydraulic chamber ₆₁ of the volume fraction of the cylinder 6, the die cushion pad 1a is secondary lifting upward by the cushion action of the cushion cylinder 2.

That is, the hydraulic chamber 6 of the auxiliary lift cylinder 6
By setting the volume of ₁ in advance according to the amount of auxiliary lift, a certain amount of auxiliary lift is possible.

When the work already formed is raised by a certain amount by the auxiliary lift and transferred to the next processing station by a work transfer means (not shown),
Thereafter, the locking valve 4 is opened and the locking is released, and at the same time, the solenoid valve 10 becomes the position b and opens the logic valve 7, and the solenoid valve 11 becomes the position d and opens the logic valve 8; 12 is position e
To close the logic valve 9, the operating oil pressure is applied via the logic valve 8 to the hydraulic chamber 6 ₂ of the auxiliary lift cylinder 6.
And the piston 6a is advanced by the operating oil pressure,
Oil of the hydraulic chamber ₆₁ is to be returned to the upper chamber 3 ₁ locking cylinder 3 through the logic valve 7.

[0024] After locking the die cushion pad 2 is a lower limit position by the locking cylinder 3 and the locking valve 4 as described above, a portion of the upper chamber 3 ₁ of the hydraulic locking cylinder 3 to the hydraulic chamber ₆₁ of the secondary lifting cylinder 6 By allowing the die cushion pad 2 to flow out, the die cushion pad 2 can be reliably assisted by a certain amount.

In the above embodiment, the solenoid valves 10, 1
In order to prevent the amount of the auxiliary lift from changing due to the leak of the valves 1 and 12, the logic valves 7, 8 and 8 having almost no leak are provided.
9 are provided, and these logic valves 7, 8, 9 are connected to the solenoid valve 1
Although the control is performed at 0, 11, and 12, the logic valve may be omitted when an electromagnetic valve with less leakage is used.

[0026] In the above embodiment, if the auxiliary lift of the die-cushion pad 1a is determined by the hydraulic chamber ₆₁ of the volume of the auxiliary lift cylinder 6, it is desired to adjust the auxiliary lift, auxiliary as shown in FIG. 3 By providing a plurality of lift cylinders 6 and controlling these auxiliary lift cylinders 6 in the same manner as described above, the amount of auxiliary lift can be adjusted.

If the stroke adjusting means 15 for adjusting the stroke of the piston 6a as shown in FIG.
This makes it possible to adjust the auxiliary lift amount. That is, a stopper 15a for adjusting the movement stroke of the piston 6a is provided in the auxiliary lift cylinder 6, and the stopper 15a
The screw portion of the adjusting rod 15b that is more protruded is screwed into a nut 15c fixed to the end of the auxiliary lift cylinder 6.

When adjusting the stroke, the tip of the adjusting rod 15b is rotated by a tool, and the stopper 15a is moved by screw feed.
By fixing the rotation of the adjusting rod 15b by the rotation preventing piece 15d, the auxiliary lift amount can be arbitrarily adjusted.

The above is the case where the auxiliary lift cylinder 6 is controlled by using an electromagnetic valve or the like.
It hydraulic chamber 6 ₂ side of FIG. 5 (b) to be connected to the damper unit 16 as shown in (c). 5 (a) urges the piston 16b inside the damper 16a by the compression spring 16c, FIG. 5 (b) urges the piston 16b with the compressed gas, and FIG. 5 (c) urges the piston 16b with the compressed air. With the opening of the logic valve 7 and the locking cylinder 3
Hydraulic chamber 6 ₁ oil pressure in the upper chamber 3 ₁ auxiliary lift cylinder 6
When flowing to the hydraulic pressure in the hydraulic chamber 6 ₂ flows into the damper 16a.

[0030] When the the locking is released the die cushion pad 2 die cushion pad 2 starts to rise, oil pressure in the damper 16a is pushed into the hydraulic chamber 6 _second auxiliary lift cylinder 6, the piston of the auxiliary lift cylinder 6 6a comes to be stroked to the original position.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an auxiliary lift device for a press die cushion according to an embodiment of the present invention.

FIG. 2 is an operation explanatory view of an auxiliary lift device for a press die cushion according to an embodiment of the present invention.

FIG. 3 is a circuit diagram showing an auxiliary lift device for a press die cushion according to another embodiment of the present invention.

FIG. 4 is a sectional view of a preliminary lift cylinder used for an auxiliary lift device of a press die cushion according to another embodiment of the present invention.

FIGS. 5A to 5C are explanatory views of damper means used for an auxiliary lift device of a press die cushion according to another embodiment of the present invention.

[Explanation of symbols]

1a ... die cushion pad 2 ... cushion cylinder 3 ... locking cylinder 3 ₁ ... upper chamber 4 ... locking valve 6 ... auxiliary lift cylinder 6a ... piston 15 ... stroke adjusting unit 16 ... damper means

Claims (4)

[Claims] 1. A cushion cylinder 2 for elastically supporting a dicing pad 1a;
In the press die cushion with locking cylinder 3 and the locking valve 4 for locking the a the lowered position, the upper chamber 3 ₁ side of the locking cylinder 3, after locking of the die cushion pad 1a, upper chamber 3 ₁
An auxiliary lift device for a press die cushion, wherein an auxiliary lift cylinder 6 for auxiliary lifting of the die cushion pad 1a by allowing a predetermined amount of hydraulic pressure to flow out is connected. 2. The auxiliary lift device according to claim 1, wherein the auxiliary lift amount can be adjusted in a plurality of stages by connecting a plurality of auxiliary lift cylinders 6 in parallel. 3. The auxiliary lift device according to claim 1, wherein a stroke adjusting means for adjusting the stroke of the piston is provided on the auxiliary lift cylinder so that the auxiliary lift amount can be adjusted steplessly. 4. A damper means 16 is provided on the auxiliary lift cylinder 6.
The auxiliary lift device according to claim 1, wherein the piston 6a is stroked by the damper means 16 after the auxiliary lift.