JPH0246928A - Hydrostatic pressure forming device - Google Patents

Abstract

PURPOSE:To control the movement of a piston or a cylinder and to raise the forming pressure by providing an opposing means for fixing one of the piston or the cylinder of a chamber, moving the other and holding a hydrostatic pressure chamber in prescribed forming pressure, and improving the drawing pressure at the time of determined drawing by a punch. CONSTITUTION:A blank material B is placed on a die 24, a pressure board 29 is allowed to descend and the blank material B is inserted and held. Subsequently, when a punch 27 is allowed to go into a hydrostatic pressure chamber 25 from the die 24 side, the capacity being roughly equal to the capacity at the time when the punch 27 has entered into the hydrostatic pressure chamber 25 is secured, therefore, a cylinder 23 ascends and by hydrostatic pressure of the hydrostatic pressure chamber 25 which is generated by pressing force of the punch 27 and pressing force of the pressure board 29, drawing is executed by using the punch 27 as a male die. In such a state, at the determined drawing stage, it is necessary to add force for opposing the ascending force of the cylinder 23, and the hydrostatic pressure of the hydrostatic pressure chamber 25 is raised by an opposing means 37.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a fluid pressure forming processing device, which is used to draw blank materials such as thin plates to obtain automobile parts, electrical parts, aircraft parts, etc. used.

(Prior Art) A chamber having a die and a fluid pressure chamber opened on the die side, a punch disposed opposite the chamber so as to be able to enter into the fluid pressure chamber from the die side, and a punch disposed opposite the chamber. a pressurizing plate that can be pressed on the chamber side, and a fluid that draws and forms a blank material whose fluid pressure chamber is closed on the die using fluid pressure through entry of a punch into the fluid pressure chamber. The pressure forming processing method and equipment are described in “Hydroforming method” published on October 25, 1975.
It is known from page 498 of the Press Working Handbook, and
It is also disclosed in Japanese Patent Publication No. 60-56569.

In FIGS. 5 and 6, a chamber 1 is fixed on a table 2, has a fluid pressure chamber 3 therein, and is equipped with a die 4.

A pressure plate (blank holder) 5 is provided so as to be able to be pressed against the chamber 1 side via a piston rod 6.

A punch 7 is provided so as to be able to enter into the fluid pressure chamber 3 from the die 4 side. 8 is a check valve for high pressure charging, 9 is a check valve for fluid charging, 10 is a high pressure charging motor, 11 is a high pressure charging pump, 12 is a fluid charging motor, 13 is a fluid charging pump,
14 is a pressure gauge, 15 is an electromagnetic switching valve, 16 is a relief valve, and 17 is a fluid tank.

That is, the blank material 18 which has been placed on the die 4 to close the fluid pressure chamber 3 is sandwiched between the die 4 and the die 4 via the pressure plate 5, and the punch 7 is pushed into the fluid pressure chamber 3. As a result, the punch 7 is placed over a male mold, and hydrostatic molding is performed by the opposing hydraulic pressure generated within the fluid pressure chamber 3.

In this case, the relief valve 16 operates to maintain the pressure within the fluid pressure chamber 3 at a predetermined pressure.

The fluid flowing out from the fluid pressure chamber 3 into the tank 17 due to molding is transferred to a fluid charging motor 12 and a pump 13 for the next molding.
is returned to the fluid pressure chamber 3.

Fluid pressure during molding is prevented from acting on pumps 11 and 13 by check valves 8 and 9.

When molding a product, it is necessary to change the pressure inside the fluid pressure chamber 3 to a predetermined pressure depending on the shape of the product and the degree to which the punch 7 enters the fluid pressure chamber 3. A method is adopted in which a valve is used and the opposing valve is adjusted by the downward stroke of the punch.

In particular, high pressure must be generated at the final stage of molding for conical reflector plates for lighting equipment and doors for automobile parts that have shallow apertures and complex patterns on their surfaces. The relationship between the punch stroke and the pressure inside the fluid pressure chamber 3 in such a case is shown in FIG.

In this case, high pressure generation means include adjusting the electromagnetic proportional relief valve mentioned above, cutting off the relief circuit with the electromagnetic switching valve 15 at the stroke limit of the punch 7, as shown in Fig. 5.6, and A method is adopted in which the fluid pressure chamber 3 is charged with high pressure using the charging motor 10 and the pump 11.

(Problems to be Solved by the Invention) The conventional technology described above has advantages such as being able to easily obtain high pressure compared to rubber molding (and pressure acts uniformly, etc.), but the fluid pressure chamber (chamber) Since the internal pressure is regulated using a pressure regulating device such as a throttle valve, there are the following problems.

First, there is a serious drawback in that when the fluid (liquid) in the chamber is forced out through the throttle valve, a large amount of energy is lost.

Furthermore, the liquid must be re-supplied into the chamber, i.e. before the next molding process begins, which means a loss of time and reduces the working speed (processing production cycle). There is a problem with time constraints.

In addition, pressure regulators are susceptible to liquid contamination and are therefore susceptible to dust and other contaminants that may arise from the workpiece (blank), which can disrupt processing operations. There is a problem with this.

In particular, in the prior art, when a high-pressure pump is used for high-pressure forming in the final drawing stage, (a); a high-pressure pump circuit is required, making it complicated and expensive. (b); Time loss occurs due to high-pressure charging by the high-pressure pump and control of increasing the counterforce of the punch in accordance with the high-pressure charging. (C): If the punching force is weak and the punch is pushed up by the high-pressure charge, the product will be distorted, and if the punching force is increased too strongly, the punch will descend, resulting in poor drawing depth accuracy of the product.

In addition, when using an electromagnetic proportional relief valve, (a)
; Pressure must be increased by driving the punch, resulting in high-pressure squeezing, which may have an adverse effect depending on the shape of the product. (b); The drawing depth accuracy of the product is poor.

(C); A high pressure relief valve is required. Furthermore, due to the generation of high pressure, force is applied to the pressure plate (blank holder), so it is necessary to increase the pressing force of the pressure plate (blank holder), but this is the maximum allowable pressure plate (blank holder) pressure amount of the press. constrained by

Therefore, the present applicant has proposed the fluid pressure forming processing apparatus shown in Figs. 3 and 4 in Japanese Patent Application No. 103176/1983 (hereinafter also referred to as a comparative example as it is not a publicly known technology). .

That is, as shown in FIGS. 3 and 4, this comparative example includes a chamber 20 having a die 24 and a fluid pressure chamber 25 that is open on the die 24 side, and a chamber 20 that has a die 24 and a fluid pressure chamber 25 that is open from the die 24 side. It includes a punch 27 disposed facing the chamber 20 and a pressure plate 29 disposed facing the chamber 20 and capable of pressing independently of the punch 27 on the chamber 20 side. room 2
The blank material B is inserted into the fluid pressure chamber 25 of the punch 27 while the periphery of the die 24 of the blank material B, which has been closed at 5, is sandwiched between the chamber 20 side and the pressure plate 29 side. The chamber 20 is made up of a piston 22 and a cylinder 23, and one of the piston 22 and the cylinder 23 is fixed or stationary, and the other is relatively moved to form the fluid pressure chamber 25. It is designed to maintain a predetermined forming pressure without discharging the fluid inside from the fluid pressure chamber 25, and in the final stage of drawing forming by the punch 27, the bunch pressing force is applied to the pressing plate 29.
This technology is equipped with a retaining means 31 that imparts transmission to the side.

Although this comparative technology solves the problems of the conventional technology described above, it was necessary to apply force from the press to counter the upward force of the cylinder 23, resulting in an increase in press oil.

It is an object of the present invention to provide a fluid pressure forming processing apparatus that can reduce the size of the press relative to the workpiece, in contrast to the prior art described above.

(Means for Solving the Problems) The present invention includes a chamber 20 having a die 24 and a fluid pressure chamber 25 opened on the die 24 side, and a chamber 20 facing the chamber 20 such that the fluid pressure chamber 25 can be entered from the die 24 side. A pressurizing plate 29 is provided, which is arranged to face the chamber 2o and can be pressed independently of the punch 27 on the chamber 20 side, and closes the fluid pressure chamber 25 on the die 24. Dice 24 of blank material B placed aside
In a method in which the blank material B is drawn and formed by fluid pressure through the entry of the punch 27 into the fluid pressure chamber 25 while the periphery is sandwiched between the chamber 20 side and the pressure plate 29 side,
In order to achieve the stated purpose, the following technical measures were taken.

That is, in the present invention, the chamber 20 is made up of a piston 22 and a cylinder 23, and the piston 22 or the cylinder 23 is
One of them is fixed or stationary, and the other is relatively moved to maintain a predetermined molding pressure in the fluid pressure chamber 25, and the movable member in the chamber 20 is moved during the drawing process using the punch 27. This is characterized in that the throttle pressure is improved by restricting the rise of 22 or 23.

(Function) According to the present invention, a blank material B such as a steel plate is placed on the die 24 so as to close the fluid pressure chamber 25 as shown in FIG. top surface)
The blank material B around the die 24 is pressed against the pressure plate 2.
9 and the chamber 20 side work together to pinch it.

Next, insert the punch 27 into the fluid pressure chamber 25 from the die 24 side.
When the punch 27 enters the fluid pressure chamber 25, the volume of the pressure medium in the fluid pressure chamber 25 does not change substantially. Therefore, in this illustrated example, the cylinder 23 of the chamber 20 is is raised, and the fluid pressure in the fluid pressure chamber 25 generated by the pressing force of the punch 27 and the pressing force of the pressing plate 29 performs hydrostatic forming and drawing forming using the punch 27 as a male mold.

In the drawing step, it is necessary to apply a force counteracting the upper bound force of the cylinder 23, which is regulated by the counter means 37, and the fluid pressure within the fluid pressure chamber 25 increases.

(Example) Hereinafter, specific examples of the present invention will be described in detail with reference to the drawings.

1 and 2 show specific examples of the present invention, and 2
0 is a chamber, which consists of a piston 22 that is fixed or stationary on a base 21 provided on the bed of the press, and a cylinder 23 that is slidably fitted to this piston 22. A die 24 is attached to form a fluid pressure chamber 25 inside.

A seal 26 is provided at the sliding portion between the piston 22 and the cylinder 23 to prevent leakage of the pressure medium contained in the fluid pressure chamber 25.

Furthermore, in the illustrated example, the piston 22 is fixed or stationary on the base 21, and the cylinder 23 is slidably fitted therein, but the cylinder 23 side is fixed or stationary as a bottomed shape, and the piston 22 side is slidably fitted. The piston 22 or the cylinder 23 may be freely movable, and in any case, it is sufficient that either the piston 22 or the cylinder 23 is fixed or stationary, and the other is relatively movable.

27 is a punch which can enter into the fluid pressure chamber 25 from the die 24 side and is disposed facing the chamber 2 (R). It is connected to a driving force acting member.

In addition, this punch 27 is used in the so-called IJj during drawing forming.
The cross-sectional area of the punch 27 is made smaller than the cross-sectional area weight of the fluid pressure chamber 25 (piston 22), so that the axis of the fluid pressure chamber 25 and the axis of the punch 27 are aligned with each other. have been matched.

29 is a pressure plate (blank holder), and by connecting the piston 22 side 30^ of the blank holder cylinder device 30, it can freely approach and separate from the cylinder 23 through the top surface of the chamber 20, substantially through the die 24. This makes it possible to apply pressure to the cylinder 23.

Reference numeral 31 denotes a holding means, which integrates or fixes the bunch 27 side and the pressure plate 29 side in the downward direction in the final stage of drawing forming by the punch 27, as shown in FIGS. 1 and 2. In the embodiment, an annular stopper 32 is fixed with bolts or the like or integrally formed on the pressure plate 29, and the crosshead 28 engages with the stopper 32.

Reference numeral 33 denotes a cylinder stopper, which is constructed by providing a stopper pin 35 on the piston pedestal 34 so as to be movable up and down, and also providing a spring 36 on the bottle 35 to spring upward.

Reference numeral 37 denotes a countermeasure, which restricts the upward movement of the movable member 22 or 23 in the chamber 20, in this example the cylinder 23, during the drawing process using the punch 27, and which controls the movement of the auxiliary cylinder 47 between the cylinder 23 and the fixed base. 21, the pulping means 48 is switched by detecting when the decisive throttle is reached, and the auxiliary cylinder 47 pulls the cylinder 23 downward with a force corresponding to the upward force of the cylinder 23, thereby increasing the decisive throttle pressure. I'm trying to raise it.

The auxiliary cylinder 47 consists of a tube 47A attached to the base 21 etc. and a piston 47B fitted to the tube 47A.The piston 47B is attached to the cylinder 23 with a nut 47C etc., and receives fluid pressure from the motor M and pump P. The circuits 48A, 4 are connected to the auxiliary cylinder 47 via valve means 48.
8B, and in FIG. 2, 49 indicates a relief valve.

Next, the drawing cycle of the blank material B in the first specific example will be explained.

In the initial position (start position) shown in FIG. 1, the punch 27 and the pressure platen 29 are positioned at a certain distance from the top surface of the die 24 for loading the blank material B,
The cylinder 23 is held at a balanced height via the spring 36 of the cylinder stopper 33, the surface of the pressure medium is located near the opening of the die 24, and a blank material B such as a steel plate is placed on the die 24. The opening of the fluid pressure chamber 25 is closed.

Next, the punch 27 and the pressure plate 29 are lowered simultaneously in synchronization, or the pressure plate 29 is lowered before the punch 27, so that the lower surface of the pressure plate 29 contacts the blank material B in either case. Here, the blank material B acts as a blocker for the fluid pressure chamber 25.

At this time, a rigid stopper is placed separately on the spring 36 part, and the pressure plate 2
A downward force of 9 may be maintained via the cylinder 23 of the chamber 20.

Next, punch 27 while maintaining or maintaining the stated state.
When the punch 27 is moved downward, that is, toward the blank material B, and the punch 27 is entered into the fluid pressure chamber 25 from the die 24 side through the opening, the pressure medium capacity in the fluid pressure chamber 25 remains almost unchanged. In this embodiment, the cylinder 23 of the chamber 20 is raised to ensure a volume approximately equal to the volume entered by the punch 27 into the fluid pressure chamber 25, and the fluid generated by the pressurizing force of the punch 27 and the pressurizing plate 29 is Pressure chamber 2
Hydrostatic forming and drawing are performed using the punch 27 as a male die using the fluid pressure in the chamber 5, that is, the forming pressure (opposed hydraulic pressure).

Pressing down the punch 27 and the blank material B into the fluid pressure chamber 25 means attempting to reduce the volume of the chamber 25.

However, this volume reduction is compensated by the fact that the cylinder 23 is moved upwardly as indicated by arrow C in a relative movement due to the pressure in the fluid pressure chamber 25, ie the molding pressure.

This means that it is not necessary to discharge the incompressible pressure medium from the fluid pressure chamber 25, and the pressure in the fluid pressure chamber 25, that is, the molding pressure is determined simply by the area ratio of the punch 27 and the piston 22 and the blank holder cylinder device. It is adjusted by the magnitude of the force exerted by 30.

As drawing progresses, the cylinder 23 rises as indicated by arrow C, but the upper limit of the rise of the cylinder 23 is restricted by engaging the stop collar 32 of the stopper means 31. At the same time as the stopper means 31 is engaged, the auxiliary cylinder device 47 is actuated to pull the cylinder downward.

That is, when the blank material B is narrowed down by the punch 27, the force that the cylinder 23 tends to rise due to the fluid pressure is borne by the fixed side (base 21) via the countermeasure 37, and the fluid pressure Pa is high. Become.

To explain this in comparison with comparative examples (FIGS. 3 and 4), the fluid pressure P generated during the decisive throttling. is basically determined by the following equation.

P from M-^1xPo. =M-, and in the comparative example without the cylinder ^1 23 countermeasure, p, =
becomes.

On the other hand, since the present invention has the counter 37, M = A 2 X PO from P. = M2, and the liquid pressure is P. However, it means to become expensive (in addition,
M is the full force of the breath, which is FFO + FIIO).

More specifically, the rising force P that acts on the cylinder 23 from the time when the rising of the cylinder 23 is restrained and regulated by the countermeasure means 37. X(At-A2) can be shared by the counter means 37, and when the punch 27 further enters the fluid pressure chamber 25, the sealed fluid (pressure medium) is compressed and the pressure increases.

The drawing process progresses, and in the final stage, the engaging means 3
1 is engaged.

That is, in FIGS. 1 and 2, the lower surface of the crosshead 28 is engaged with the stopper 32, and the punch 27 side and the pressure platen 29 side are integrated here, and the punch 27 and the pressure platen 29 side are integrated here.
As a result, the drawing depth of the product is set, and a portion of the pressing force from the crosshead 28 is transferred to the pressing force by the pressure plate 29, and the pressure in the fluid pressure chamber 25 is increased. is increased, and molding is performed using opposing hydraulic pressure using the punch 27 as a male die at a higher pressure.

When the prescribed molding is completed, the punch 27 is pulled up, the pressure platen 29 is also raised, and the molded product is taken out. At this time, the cylinder 23, etc. is under its own weight or the auxiliary cylinder 2347
It descends and comes to rest in a balanced position using the springs 36 or the auxiliary cylinder device 47.

(Effects of the Invention) The present invention has been described in detail above, and has the following advantages.

The chamber that forms the fluid pressure chamber that accommodates the pressure medium (fluid) is composed of a relatively slidable cylinder and piston, so during pressure molding with the fluid, the pressure medium in the fluid pressure chamber is removed through a throttle valve, etc. There is no need to let the fluid escape, and therefore there is no significant energy loss or abnormal temperature rise of the pressure medium. This eliminates the need to re-supply a large amount of pressure medium, making it possible to simplify installation and improve production cycle time.

In addition, since a countermeasure is provided to restrict the rise of the movable member in the chamber during the drawing process using the punch, the full force of the press can be used effectively to increase the fluid pressure within the fluid pressure chamber. The hydrostatic molding pressure for forming a male mold can be increased, and a sufficient molding force can be ensured.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, a conventional example, and a comparative example. Fig. 1 is an elevational sectional view at the start of the first embodiment of the present invention, and Fig. 2 is an elevational sectional view at the final stage of drawing forming. Figure 3 is an elevational sectional view at the start of the comparative example;
Fig. 4 is an elevational sectional view at the final stage of drawing forming, Fig. 5 is an elevational sectional view showing the blank material being held down by a press plate according to the conventional example, and Fig. 6 is an elevational sectional view showing the forming process state of the conventional example. The cross-sectional view and FIG. 7 are graphs showing the relationship between the pressure of the fluid pressure chamber and the punch stroke. 20...Chamber, 22...Piston, 27...
cylinder, 24... die, 25... fluid pressure chamber, 2
7... Punch, 29... Pressure plate (blank holder)
, 37... Countermeasures.

Claims (1)

[Claims] (1) A chamber 20 having a die 24 and a fluid pressure chamber 25 opened on the die 24 side; a punch 27 disposed opposite to the chamber 20 so as to be able to enter the fluid pressure chamber 25 from the die 24 side; A die 24 of the blank material B, which is provided with a pressurizing plate 29 that is disposed opposite to the chamber 20 and can be pressed independently of the punch 27, and has a fluid pressure chamber 25 closed on the die 24. In a method in which the blank material B is drawn and formed by fluid pressure through the entry of the punch 27 into the fluid pressure chamber 25 while the periphery is sandwiched between the chamber 20 side and the pressure plate 29 side, the chamber 20 is a piston. 22 and a cylinder 23, either the piston 22 or the cylinder 23 is fixed or stationary, and the other is relatively movable to maintain the inside of the fluid pressure chamber 25 at a predetermined molding pressure, At the drawing stage using the punch 27, the chamber 2
A fluid pressure forming processing apparatus characterized in that it is provided with an opposing means 37 that restricts the rise of the movable member 22 or 23 at 0 and increases the drawing pressure.