JPH0337807B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for replenishing hydraulic oil in a forging and forming apparatus in which a material is pressurized in double action by upper and lower punches.

(Conventional technology) In forging forming equipment, double action is required to achieve burr-free closed forging and process integration.
Japanese Patent Publication No. 55-46255 discloses a device that achieves double action by combining general-purpose press devices instead of using a special double-action press device.

Specifically, the upper and lower punches are slidably assembled into a pair of split molds provided on the upper and lower die sets, and the upper punches are connected to a press device, while a sub-cylinder that is activated by the lowering of the upper die set is connected to the sub-cylinder. The lower die set is provided with a main cylinder that communicates with the lower die set, the lower punch is supported by the main piston, and the lower punch is pushed up by the rise of the main piston.

(Problems to be Solved by the Invention) Such a device has a very simple structure and is reliable as a method for obtaining vertical synchronization, but since it is composed of a hydraulic circuit, high pressure is applied. Due to the fact that the entire device is elastically deformed (bending) due to the molding load, the hydraulic circuit (or the seal portion) is destined to leak, albeit a small amount of hydraulic fluid in the circuit.

In addition, in the event of an overload, a replenishment system is required to safely reef the oil, quickly recover the oil, and return it to the original circuit. Particularly in lateral extrusion molding, precise synchronization and strokes and their reproducibility are required, and replenishment is essential to fill the oil without running out.

For this reason, oil is constantly replenished by air pressure through a check valve, but a complicated suction phenomenon occurs during molding or when the main piston is operating, and if replenishment is constantly carried out, more oil than necessary is drawn in and the main piston becomes unable to return to its original position (bottom dead center).

In this case, the main piston position, that is, the lower punch position, gradually rises, causing variations in the stroke, which causes problems. This is because the main circuit is a closed circuit to generate molding pressure, and once excess oil is sucked in, it does not return to its original state and the pressure in the circuit increases.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides the above-mentioned forging forming apparatus such that when the upper die set 1 is lowered, the sub-piston 32 is lowered, and at the same time the main piston 2 is lowered.
After the upper die set 1 rises and the sub-piston 32 and the main piston 22 return to their original positions, the hydraulic pressure is released to securely hold the main piston 22. The replenishment timing is set so that the pressure release section R for returning to the original position and the hydraulic oil replenishment section S do not overlap.

(Function) Since the molding zone U, pressure release zone R, and hydraulic oil supply zone S are independent without wrapping, they are maintained in a closed circuit during molding to ensure that sufficient molding pressure is obtained, and after molding. It is possible to reliably return the main piston 22 to its original position, and also to ensure proper replenishment by eliminating excess or shortage of oil, thereby allowing the device to operate safely and accurately.

(Example) Examples will be described in detail below based on the accompanying drawings.

Fig. 1 is a longitudinal sectional view of the forging forming device, and Fig. 4 shows its circuit configuration, in which 1 is an upper die set, 2 is a lower die set, 3 is an upper die, 4 is a lower die, 5 is an upper punch, 6 is a lower punch, 7 is a side punch,
The upper die set 1 is fixed to a ram 8, and the lower die set 2 is fixed to a bolster 9.

A cylinder 11 is provided at the center of the upper die set 1, and an upper hydraulic chamber 13 of the cylinder 11 into which a piston 12 is fitted communicates with an accumulator 15 via an oil passage 14 of the upper die set 1. Mold 3 is fixed. Further, an upper punch 5 is inserted into the piston 12 so as to be slidable up and down, and the upper punch 5 is connected to a press device (not shown).

On the other hand, a main cylinder 21 is provided at the center of the lower die set 2, and an upper hydraulic chamber 23 of the main cylinder 21 into which a main piston 22 is fitted is connected to an accumulator 25 via an oil passage 24 of the lower die set 2.
The lower punch 6 is connected to the main piston 22.
is mounted so as to be able to rise, and this lower punch 6 is connected to a knockout device (not shown). Further, a lower mold 4 is fixedly installed above the center of the lower die set 2. Further, a sub-cylinder 31 is provided around the lower die set 2, and a lower hydraulic chamber 36 of the sub-cylinder 31 into which the sub-piston 32 fits is connected to the lower hydraulic chamber 2 of the main cylinder 21 via an oil passage 37 of the lower die set 2.
It communicates with an oil passage 27 to 6. In the embodiment, four sub-cylinders 31 corresponding to the cross-sectional area of the main cylinder 21 are provided, and the lower hydraulic chambers 36 of the four sub-cylinders 31 communicate with each other.

In addition, each sub-piston 32...
A pusher 18 for pressing the upper surface of the die set is fixedly suspended, and four pairs of guide posts 29 and guide holes 19 are provided in the upper and lower die sets 1 and 2.

Further, a side cylinder 41 is provided above the lower die set 2, and a front hydraulic chamber 43 of the side cylinder 41 into which a side piston 42 is fitted is connected to an oil passage 4.
4, and the rear hydraulic chamber 46 communicates with the oil passage 37 via an oil passage 47. Further, a side punch 7 is fixed to the side piston 42 so as to be able to move forward and backward between the upper and lower molds 3 and 4 forming a split mold, and the forward position of this side punch 7 is regulated by a stopper 49. In the embodiment, four side cylinders 41... and two side punches 7, 7 are provided, and one side punch 7
Two side pistons 42, 42 are connected to each other.

Next, we will discuss the hydraulic circuit.

An oil passage 3 that communicates between the lower hydraulic chamber 36 of the sub cylinder 31 and the lower hydraulic chamber 26 of the main cylinder 21
A sequence valve 51 is installed between the main cylinder 21 and the sub cylinder 31.
A pressure-responsive valve 53 is arranged in parallel to allow oil to flow to the main cylinder 21 when the side oil pressure exceeds the installation pressure.

A replenishment circuit 61 is connected to the oil passage 27 between the sequence valve 51 and the main cylinder 21, and the replenishment circuit 61 includes a replenishment tank 63 to which air pressure from an air source 62 is sent to the upper part, and a replenishment tank 6.
A solenoid valve 64 that switches and controls the flow of oil from the main cylinder 21 according to the replenishment timing, a check valve 65 that is arranged in parallel to this and prevents oil from returning from the main cylinder 21 to the tank 63, and its oil pressure is set to a set pressure. It consists of a pressure-responsive valve 66 that returns the water to the tank 63 when the pressure exceeds the pressure.

Further, a manually operated stop valve 71 is installed in the oil passage 47 that communicates the lower hydraulic chamber 36 of the sub-cylinder 31 with the rear hydraulic chamber 46 of the side cylinder 41, and further downstream of the stop valve 71 is a back-back prevention circuit 81 for the side piston 42. will be installed. This backward prevention circuit 81 includes a check valve 82 that prevents oil from flowing out from the rear hydraulic chamber 46, and a check valve 82 that prevents oil from flowing out from the rear hydraulic chamber 46.
2 is comprised of a solenoid valve (not shown) for switching operation according to the oil pressure of the accumulator 25 so that it functions only during molding.

An example of the operation of the forging forming apparatus described above will be described below.

Before molding, the ram 8 is in the raised position, and after setting the preform product W of a stove rod made of, for example, A-powder composite material on the lower punch 6 facing into the lower mold 4 in the opened state, the ram 8 is lowered. Then, the upper mold 3 is closed on the lower mold 4.

At the same time as this mold closing, the sub-piston 32 of the lower die set 2 is pushed down by the lowering of the pusher 18 of the upper die set 1, and the hydraulic pressure in the lower hydraulic chamber 36 first acts on the rear hydraulic chamber 46 of the side cylinder 41, and the side piston 42 is pressed down. with side punch 7
moves forward. During this time, the oil in the front hydraulic chamber 43 of the side cylinder 41 is discharged to the accumulator 25.

When the forward movement of the side punch 7 is regulated by the stopper 49 and the lateral pressurization of the preform product W is completed, and the pressure in the oil passage 37 rises and reaches the set pressure, the pressure-responsive valve of the sequence valve 51 53 opens, the hydraulic pressure acts on the lower hydraulic chamber 26 of the main cylinder 21, the lower punch 6 rises together with the main piston 22, and in synchronization with this, the upper punch 5 descends due to the operation of the press device.

In this way, the lower punch 6 and the upper punch 5 operate in double motion in synchronization, and pressurize the preform product W in double motion from above and below to complete the forming. In this case, the side punch 7 is held in the forward position by the action of the backward prevention circuit 81. Furthermore, during this period, the oil in the upper hydraulic chamber 23 of the main cylinder 21 is discharged to the accumulator 25, and oil is supplied from the accumulator 15 to the upper hydraulic chamber 13 of the cylinder 11 in the upper die set 1, and the upper die with respect to the lower die 4 is The clamping force of the mold 3 is maintained at a predetermined value.

After forming is completed, the ram 8 rises and the upper punch 5 rises, and the front hydraulic chamber 43 of the side cylinder 41 and the upper hydraulic chamber 23 of the main cylinder 21
At the same time, oil is reduced from the accumulator 25,
The side punch 7 retreats, and at the same time the lower punch 6 descends. As a result, the rear hydraulic chamber 46 of the side cylinder 41 and the lower hydraulic chamber 2 of the main cylinder 21
6 returns to the lower hydraulic chamber 36 of the sub-cylinder 31, and the sub-piston 32 returns to the raised position.

After that, the lower punch 6 is activated by the knockout device.
The chisel rises again and pushes up the product, completing the dispensing.

In the above, in order to cope with a small amount of oil leaking in the hydraulic circuit, oil is replenished as shown in the timing chart of FIG.

That is, in FIG. 5, a hatched area U is a molding section in which the main piston 22 ascends, a diagonal line D is a return section in which the main piston 22 descends after completion of molding, and after that, an allowance section P is provided before the lower part of the main cylinder 22 is moved. A pressure release section R in which the hydraulic chamber 26 is released to the atmosphere by the supply circuit 61 via the oil path 27
will be established. That is, in the pressure release section R, the supply of air pressure to the tank 63 is cut off by the solenoid valve 67, and the oil remaining in the lower hydraulic chamber 26 is released from the tank 63 by opening the solenoid valve 64.
will be returned to.

After this pressure release section R, a sufficient margin section P is provided, and then a replenishment section S is provided by the replenishment circuit 61 in preparation for the next machining cycle. That is, in the replenishment section indicated by the shaded area S, the solenoid valve 67 is opened to supply air pressure into the tank 63, and the solenoid valve 64 is closed to drain the oil in the tank 63 to the sequence valve 51 and the main cylinder 2.
The oil passages 27 and 37 between the oil passages 1 and 1 are replenished.

After the replenishment section S, the solenoid valve 67 is shut off again, and after a sufficient margin section P is provided, the next forming section U is started.

In this way, the cycle is in the following order: <Replenishment section> → <Margin section> → <Forming section> → <Return section> → <Margin section> → <Pressure release section> → <Margin section> → <Replenishment section> Set the timing to .

Incidentally, the timing of the operation of the side piston 42 and the main piston 22 can be freely adjusted depending on the molded product by setting the set pressure of the sequence valve 51 and the stopper position of the sub-piston 32. For example, it is possible to operate the side piston 42 and the main piston 22 simultaneously, to operate the main piston 22 first, or to operate only the side piston 42 or the main piston 22.

(Effects of the Invention) As described above, according to the present invention, sufficient molding pressure can be reliably obtained by holding the main piston in a closed circuit during molding, and the main piston can be reliably returned to its original position after molding. Moreover, it eliminates excess or deficiency of oil in the circuit and ensures proper replenishment.
The device can be operated safely and accurately.

[Brief explanation of the drawing]

Figure 1 is a longitudinal cross-sectional view of the forging equipment, Figure 2 is a plan view of the lower die set, Figure 3 is a bottom view of the upper die set, Figure 4 is a configuration diagram of the hydraulic circuit, and Figure 5 is the replenishment timing line. It is a diagram. In addition, in the drawing, 1 and 2 are upper and lower die sets, 3,
4 is the upper and lower mold forming the split mold, 5 and 6 are the upper and lower punches, 7 is the side punch, 18 is the pusher, 2
1 is the main cylinder, 22 is the main piston, 2
6 is a lower hydraulic chamber, 31 is a sub-cylinder, 32 is a sub-piston, 36 is a lower hydraulic chamber, 41 is a side cylinder, 42 is a side piston, 46 is a rear hydraulic chamber, 49 is a stopper, 51 is a sequence valve,
61 is a supply circuit, 62 is an air source, 63 is a supply tank, 64 is a solenoid valve, 71 is a stop valve, and 81 is a reverse prevention circuit.

Claims (1)

[Claims] 1. Upper and lower punches are slidably assembled into a pair of split molds provided on the upper and lower die sets, and the upper punches are connected to a press device, while a sub-cylinder and the sub-cylinders are operated by lowering of the upper die set. A main cylinder communicating with the cylinder is provided in the lower die set, the main piston supports the lower punch, and the lower punch is pushed up as the main piston rises, and hydraulic oil is supplied to the sub cylinder and the main cylinder. In a forging forming device designed to
At the same time, the main piston rises to complete the forming section, and after the forming is completed, the upper die set rises, the sub-piston and main piston return to their original positions, and then the hydraulic pressure is released to ensure that the main piston returns to its original position. A method for replenishing hydraulic oil for forging and forming equipment, characterized by setting replenishment timing so that a pressure release section to be restored and a hydraulic oil replenishment section do not overlap.