JPH01273620A - Fluid-pressure fabrication method and device - Google Patents

Abstract

PURPOSE: To prevent an extreme decrease of thickness of a deep drawing product by placing a blank on a die with a hydraulic pressure chamber closed, executing bulging of the blank from the lower part, and pushing a punch from the upper part into the hydraulic pressure chamber. CONSTITUTION: A blank B is placed on a die 5. The peripheral part of the blank B is held by a pressurizing disk 10 and a pressure chamber 6 is closed, and lowering the pressurizing disk 10, a reverse bulging part B3 is formed by bulging. Then, a punch 8 is lowered and from the upper part is pushed into the hydraulic pressure chamber 6 through the blank B. With the peripheral part of the blank B being fixed, the punch 8 is pushed into the die 5. Thereby, a deep drawing product is prevented from an extreme decrease of thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fluid pressure forming processing method and apparatus, which is capable of drawing a blank material such as a thin plate to produce automobile parts, electrical parts, etc.
It is used to obtain aircraft parts, etc.

(Prior Art) A dome having a die and a fluid pressure chamber opened on the die side; a punch disposed opposite the dome so as to be able to enter the fluid pressure chamber from the die side; and a dome disposed opposite the dome. Fluid pressure forming is equipped with a pressure plate that can be pressed on the side, and draws a blank material with a fluid pressure chamber closed on the die using fluid pressure by entering the punch into the fluid pressure chamber. The processing equipment is specified in the "Breath Processing Handbook°°" published on October 25, 1975, as part of the hydroforming method.
It is known from page 498, and it is also known as
It is also disclosed in Publication No. 69 and the like.

(Problem to be solved by the invention) Although the conventional technology described above has advantages such as being able to easily obtain high pressure and applying pressure uniformly compared to molding with rubber, it is difficult to solve the problem because the dome is fixed. During molding, the pressure within the fluid pressure chamber must be adjusted using a pressure regulating device such as a throttle valve, which poses 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, significant energy loss is involved.

Furthermore, the compressed liquid must be resupplied into the chamber before the next molding process begins, which means time loss and reduces the working speed (processing speed). There is a problem with constraints on production cycle time.

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 addition, prior to drawing forming using opposing hydraulic pressure with a punch, the forming portion of the blank material sandwiched between pressure plates is stretch-formed using opposing hydraulic pressure in the opposite direction to the direction in which the punch enters, and then drawing forming with the punch is performed. In the molding method that performs stretch molding, it is necessary to supply liquid from the outside into the chamber using a pump or the like, which requires a fluid supply device, which complicates the device and makes it difficult to supply the liquid. Time becomes a time loss and is accompanied by restrictions on work speed (processing production cycle time).

Furthermore, in order to accurately determine the amount of stretch molding, it is necessary to accurately control the amount of liquid to be supplied or to measure the actual amount of stretch molding, which is extremely difficult.

The present invention provides a fluid pressure forming processing method and apparatus that does not require excessive design of the press for the workpiece, minimizes energy loss, and improves the production cycle time of the press. That is the first purpose.

Furthermore, a second object of the present invention is to provide a hydroforming method and apparatus that do not require a pressure regulating device for discharging pressure medium from a chamber and are easier to control.

In addition, the present invention does not require the supply of liquid from the outside into the chamber in the above-mentioned stretch molding process, and the amount of stretch molding can be easily obtained with high precision, and its adjustment is also easy. It is a third object to provide a method and apparatus.

(Means for Solving the Problems) The present invention provides a dome 1 having a die 5 and a fluid pressure chamber 6 opened on the die 5 side, and a dome 1 having a fluid pressure chamber 6 opened from the die 5 side.
A punch 8 disposed facing the dome 1 so as to be able to enter inside the dome 1, and a pressure plate 10 disposed facing the dome 1 and capable of pressing independently of the punch 8 on the dome 1 side. The blank material B is inserted into the fluid pressure chamber of the punch 8 while the periphery of the die 5 of the blank material B on which the fluid pressure chamber 6 is closed is sandwiched between the dome 1 side and the pressure plate 10 side. 6, the following technical measures are taken to achieve the stated purpose.

That is, in the present invention, the dome 1 is composed of a piston 3 and a cylinder 4, and either the piston 3 or the cylinder 4 is fixed or stationary, and the other is relatively moved to pump the fluid in the fluid pressure chamber 6. Do not discharge from the fluid pressure chamber 6 (
It is designed to maintain a predetermined molding pressure.Furthermore, the dome 1 side and the pressure plate 10 work together to sandwich the periphery of the die 5 of the blank material B whose fluid pressure chamber 6 has been closed. The first aspect is that the movable member side of the blank material B is lowered to stretch the blank material B in a direction opposite to the descending direction with a counter liquid, and the overhang amount adjusting means 30 is provided for adjusting the reverse overhang amount. The characteristics of

Furthermore, the present invention is capable of producing a blank material by cooperating between the dome 1 side and the pressure plate 10 side, in which either one of the cylinder 4 and the piston 3 constituting the fluid pressure chamber 6 is fixed or stationary, and the other is movable relative to each other. By lowering the pressure plate 10 while fixing the periphery of B, the blank material B is reversely stretched in the opposite direction to the downward direction of the pressure plate 10 by the opposing hydraulic pressure of the fluid in the fluid pressure chamber 6, and then the blank material B is By advancing the punch 8 into the die 5 while keeping the periphery of the material B fixed, the opposite hydraulic pressure is applied while pressing the reverse overhang molded part of the blank material B against the outer periphery of the punch 8 through relative movement between the cylinder 4 and the piston 3. The second feature is that drawing is performed by.

(Function) According to the present invention, the cylinder (movable member) 4 forming a part of the dome 1 at the initial position is supported by the support device 26 and is at the normal lowered position (initial position).

At this initial position, the fluid pressure chamber 6 is placed on the die 5.
A blank material B such as a steel plate is placed so as to close the opening 58, and the pressure plate 10 is lowered to sandwich the blank material B around the opening 58 in cooperation with the pressure plate 10 and the dome 1 side.

Thereafter, when the pressure plate 10 is further lowered, the cylinder 4 is lowered, the fluid pressure chamber 6 is compressed, and the blank material B is reversely stretched in the opposite direction to the lowering direction (see Fig. 2). ).

That is, since the fluid pressure chamber 6 is closed with the blank material B, the opposite hydraulic pressure P0 is generated when the cylinder 4 descends, and reverse overhang molding is performed. It is determined by the size of the distance from the adjusting male screw 32 as a stopper.

Next, when the punch 8 enters the fluid pressure chamber 6 from the die 5 side, the volume of the pressure medium in the fluid pressure chamber 6 does not change, so it is approximately equal to the volume at which the punch 8 enters the fluid pressure chamber 6. In order to secure the volume, the cylinder 4 of the dome 1 is raised in this illustrated example, and as shown in FIG. At P, hydrostatic forming and drawing are performed using the punch 8 as a male die.

In this case, the punch 8 will start drawing after pressing down the blank material B that has been subjected to reverse stretch forming, and the stretched blank material B will be able to reach the head of the punch 8 without causing local elongation. By contacting over a large area and restraining that part by frictional force due to the opposing hydraulic pressure P, the dangerous fracture section due to drawing force becomes longer, fracture is prevented, and the thickness of the formed product is extremely reduced. is also prevented.

In this way, a predetermined deep drawing is carried out using the opposing hydraulic pressure P using the punch 8 as the male die (see FIGS. 3 and 4).

After the predetermined forming, when the punch 8 and the pressure plate 10 are raised, the cylinder 4 side of the dome 1 is lowered by its own weight and is held at the predetermined initial position 1t11.

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

1 to 4 show a first embodiment of the present invention and its operation, in which 1 is a dome, a piston 3 is fixed or stationary on a base 2, and a piston 3 is slidably fitted into the dome. A die 5 having an opening portion 5A is mounted on the cylinder 4 to form a fluid pressure chamber 6 therein.

A seal 7 is provided at the sliding portion between the piston 3 and the cylinder 4 to prevent leakage of the incompressible pressure medium contained in the fluid pressure chamber 6.

In the illustrated example, the piston 3 is fixed or stationary on the base 2, and the cylinder 4 is slidably fitted therein, but the cylinder 4 side is fixed or stationary with a bottom, and the piston 3 side is slidable. It may be movable, and in any case, it is sufficient that either the piston 3 or the cylinder 4 is a fixed or stationary member and the other is a movable member that is relatively movable.

A punch 8 is arranged facing the dome 1 so as to be able to enter into the fluid pressure chamber 6 from the die 5 side. connected.

Note that this punch 8 serves as a so-called male mold during drawing, and the cross-sectional area A of the punch 8 is the same as that of the fluid pressure chamber 6.
The cross-sectional area A1 of the piston 3 is made smaller, and the axis of the fluid pressure chamber 6 and the axis of the punch 8 are aligned with each other.

10 is a pressure plate, and by connecting the piston rod 11 of the side cylinder device, the top surface of the dome l,
A pressing force F1 can be applied to the cylinder 4 substantially via the die 5.

In the illustrated example, the press plate 10 presses the blank material B against the die 5, but a cylinder controlled by another pressure device is provided in the press plate 10, and the blank material is pressed under this cylinder. A separate pressure plate may be provided to independently control the pressing force of the blank material.

In this case, a part of the press plate 10 is brought into direct contact with the surface of the die 5 or the cylinder 4, and the press force F of the piston rod 11 is combined with the press force of the blank material by the separate press plate and the press plate 10 directly into the dome. It can be divided into 1 and the pressing force.

However, since the pressing force of the blank material is naturally transmitted to the dome 1, the force received by the dome 1 is the same as the pressing force F.

Reference numeral 26 denotes a support device, which includes a guide rod 28 that projects upward from the piston base portion 27 and is inserted into the flange portion of the cylinder 4, and is wound around the guide rod 28 to elastically hold the cylinder 4 in the initial position. It is made of an elastic material 29, shown as a coil spring, which is supported by a coil spring. Note that a plurality of the support devices 26 are arranged radially in a plan view in order to evenly support the cylinder 4.

30 is a reverse overhang amount adjusting means, and in this embodiment, the pedestal part 2
7 is provided with a female thread 31, a male head screw 32 is screwed into the female thread 31, so that the distance between the upper surface and the lower surface of the cylinder can be adjusted, and a lock nut 33 is provided. Note that the male screw 32 of this adjusting means 30
A plurality of these are arranged radially in a plan view so as to cover the cylinder 4 evenly.

34 is a stopper that, in the final stage of deep drawing, engages and integrates the punch 8 side and the pressure plate 10 side in the pressing direction, sets the deep drawing height, and adjusts the punch force and pressurizing capacity. Partially pressurized plate force F.

In this embodiment, it is provided on the pressure plate 10, but this is because the drive part on the punch 8 side and the drive part on the pressure plate 10 side are provided on the crosshead 9, etc. It may be possible to engage and integrate the mechanism at any point within the mechanism.

Further, in order to adjust the aperture height, an engagement position adjustment mechanism may be provided in the engagement portion.

In addition, when a separate pressure plate is provided in the pressure plate 10 that can obtain the pressing force of the blank material independently of the pressure force of the piston rod 11, the pressure plate and the punch 8 side are engaged and integrated. Alternatively, an engagement mechanism may be provided.

Next, a drawing cycle for the blank material B according to the first specific example will be described with reference to FIGS. 1 to 4.

The initial position (starting position) shown in Figure 1.

In the initial position), the punch 8 and the pressure platen 10 are positioned at a certain distance from the top surface of the die 5 for loading the blank material B, and the cylinder 4 is at a certain height balanced by the elastic material 29 of the support device 26. The surface of the incompressible fluid (pressure medium) is located near the opening portion 5A, and a blank material B such as a steel plate is placed on the die 5 to close the opening of the fluid pressure chamber 6.

Next, as shown in FIG. 2, the pressure plate IO is lowered and comes into contact with the blank material B.
Acts as a blocker against

Further, when the pressure plate 10 is lowered via the piston rod 11 of the side cylinder device, the elastic material 29 of the support device 26 is compressed, and the cylinder 4 is moved downward.

Although the pressure medium in the fluid pressure chamber 6 is compressed as the cylinder 4 descends, since the opening of the fluid pressure chamber 6 is closed with the blank material B, there is no far field for the pressure medium, and as a result, Blank material B has pressure medium internal pressure P. As a result, as shown in FIG. 2, the molding is reverse-stretched in a curved shape in the opposite direction to the downward direction, that is, upward.

This overhang iH of the reverse overhang molded part B3 is performed until the cylinder 4 comes into contact with the head of the male screw 32, and at this point, the male screw 32
By adjusting the size of the distance between the head of the cylinder and the cylinder 4 in advance, the overhang iH can be adjusted to the thickness of the blank material B,
It is considered to be suitable for the intended product, etc.

Next, as shown in FIG.
When moved toward the fluid pressure chamber 6, the punch 8 is moved toward the forming part B.
3 is pressed down, it is pressed into the fluid royal chamber (chamber) 6 through the opening portion 5A with a pressing force F, and the molding pressure P generated by the pressing force F and the pressing force F of the pressing plate 10 is applied thereto. , the punch 8 serves as a male mold to perform pressing, that is, drawing.

Pressing down the punch 8 and the blank material B into the fluid pressure chamber 6 means attempting to reduce the volume of the chamber 6.

However, this volume reduction is due to the fact that the cylinder 4
The internal pressure (opposed hydraulic pressure), that is, the molding pressure P, is compensated for by moving the cylinder 4 upward as shown by arrow C as a relative movement.

This means that it is not necessary to discharge the incompressible pressure medium from the fluid pressure chamber 6, there is no need to replenish the pressure medium for this purpose, there is no energy loss, and the pressure in the fluid pressure chamber 6 The molding pressure P is adjusted simply by the area ratio of the punch 8 and the piston 3 and the magnitude of the force exerted by the side cylinder device 11.

Further, by adjusting (controlling) the development of the force of the side cylinder device 11 in relation to the downward movement of the punch 8, the hydrostatic molding pressure within the fluid pressure chamber 6 can be optimized.

When the punch 8 is near the final drawing stage (in this embodiment, the cross hend 9 and the stopper 34 come into contact as shown in FIG. 4, and the punch 8 side, the pressure plate 10 side, and the dome 1 side The relative movement of the punch 8 is eliminated, the drawing depth is set, and the margin of the drive capacity of the punch 8 (the difference between the allowable capacity of the drive mechanism of the punch 8 and the force actually received by the punch 8 from the fluid pressure chamber 6) and the pressing force F of the pressing plate 10 are transmitted to the dome 1 side, where molding is performed while ensuring the maximum opposing hydraulic pressure.

When the prescribed molding is completed, the punch 8 is pulled up, the pressure platen 10 is also raised, and the molded product is taken out. At this time, the cylinder 4 descends together with the dice 5 due to their own weight, is elastically supported by the elastic material 29 in the support device 26, and comes to rest at a balanced position. In this case, the horizontal level of the pressure medium will be near the opening portion 5A.

It should be noted that it is advantageous to select a pressure medium with a relatively high viscosity value, which facilitates sealing problems. Furthermore, it is advantageous to use a fluid that has as little adhesion to the blank B as possible.

FIG. 5 to FIG. 10 show the overhang amount adjusting means 30 according to second to seventh embodiments of the present invention.

In the second to seventh specific examples, since the basic configuration is the same as that of the first specific example described above, common parts are indicated by common symbols, and only the functions of the different parts will be explained below.

FIG. 5 shows an embodiment in which the cylinder mechanism 12 and its control system 18 are used as the reverse extension amount adjusting means 30 in the first specific example. In this embodiment, the cylinder mechanism 12 is composed of a piston rod 14 having a piston 13, and a cylinder tube 15 into which the piston 13 is slidably fitted. The cylinder tube 15 is pivotally supported on the base 2 side by a bracket 16 and a pin 17.

In this figure, when the cylinder 4 is in the initial position by the support device 26 which is the initial position setting, the solenoid 35 and the solenoid 36 in the control system 18 are in the illustrated function, and the check valve 37 is opened by the pump 42. .

When the cylinder 4 is lowered by the pressure plate 10 for reverse overhang, the fluid in the cylinder mechanism 12 freely flows out from the boat 15B to the fluid tank 38 and the boat 15A of the cylinder mechanism 12, and the movable cylinder 4 is freely pushed down.

The position of the cylinder 4 is detected by the cylinder position detection sensor 39, this detection signal is calculated by the comparator 41, and the setting device 40
When the set value is reached, an excitation signal 6 is sent to the solenoid 36, the pilot pressure to the check valve 37 is released, the check valve 37 is closed, and the cylinder mechanism 12's bow 1-1 is
The pressure on the 5B side increases, the movable cylinder 4 stops, and the amount of reverse overhang molding is determined.

Subsequently, when the cylinder 4 starts to rise due to the pressure in the fluid pressure chamber 6, the fluid itself opens the check valve 37 in the boat 15B of the cylinder mechanism 12, and the fluid in the tank 38 and the boat 15Δ of the cylinder mechanism 12 opens. will flow in. In this way, when the movable cylinder 4 is raised, there is no need for any external operation.

When the molding is completed and the movable cylinder 4 is stopped, the solenoid 36 is switched to open the check valve 37. As the pan 18 rises, the pressure inside the fluid pressure chamber 6 becomes atmospheric pressure, and if the movable cylinder 4 is above its initial position, it will descend to the initial position due to its own weight, and in the unlikely event that the movable cylinder 4 returns to its initial position. If it is below the position, it is pushed up by the support device 26 and returns to the initial position. By switching the solenoid 35, when the movable cylinder 4 cannot be lowered by its own weight alone, the pump 42 applies pressure to the boat 15A of the cylinder mechanism 12 to forcibly lower it, and controls the lowering speed during the lowering of its own weight and forced lowering. It is for.

In the third specific example shown in FIG. 6, the check valve 37 in FIG. 5 is replaced with a poppet-type check valve 43 having a spring 43A shown in the figure, and its opening and closing is performed by a pusher 44 having a spring 44A. be. The position of the bushing 44 relative to the cylinder 4 is determined by a stroke adjustment screw 45, and determines the position of the movable cylinder 4 that closes the check valve 43, that is, the amount of reverse overhang. When the movable cylinder 4 starts to rise, the bushing 44 also rises, the check valve 43 is opened, and fluid can freely flow in and out of the cylinder mechanism 12. In this third specific example, the solenoid 36 and the signal generating devices for operating the solenoid 36 in the second specific example are not required, and the structure is simplified.

In FIG. 7, this fourth specific example is a case where a proportional electromagnetic relief valve 45 and a check valve 46 are used in place of the check valve 37 and the solenoid 36 that actuates it in FIG. is detected by the movable cylinder position detection sensor 39, and at its lower limit, the proportional electromagnetic relief valve 45 is closed to stop the movable cylinder 4 and determine the amount of reverse overhang molding. When the movable cylinder 4 is lowered by its own weight or forcibly after molding is completed, use the proportional solenoid relief valve 4.
Lower the set pressure in step 5. The configuration in this figure is based on the movable cylinder 4.
In addition to determining the downward stroke of the movable cylinder 4, the downward resistance of the movable cylinder 4 is adjusted by the proportional electromagnetic relief valve 45 when the pressure plate 10 is lowered via the piston rod 11 of the side cylinder device to perform reverse stretch forming of the blank material. As a result, the pressing force of the blank material can be adjusted, and it becomes possible to prevent leakage of pressure medium between the blank material and the goo in the reverse stretch molding process, and to adjust the wrinkle pressing force.

In the fifth specific example shown in FIG. 8, the solenoid 35 in FIG. 7 is replaced by a three-position solenoid 135, and the solenoid 135 is provided with a function 1358 for forcibly raising the cylinder mechanism 12 by the pump 42. This eliminates the need for the support device 26 for setting the initial position in FIG.

That is, in the event that the cylinder 4 is lowered from its initial position after completion of molding, the function 135A of the solenoid 135 raises it, the position is detected by the position detection sensor 39 of the cylinder 4, and the solenoid 1
Switch the function 35 to the position shown in the figure to stop the cylinder 4. In this case, the proportional electromagnetic relief valve 45 is automatically throttled to such an extent that the cylinder 4 does not fall.

If cylinder 4 is too high up from the initial position,
It is lowered by solenoid 135 as shown.

Similar to the fourth example, this fifth example can prevent leakage of pressure medium from between the blank material and the goo when the cylinder 4 is lowered, and can adjust the wrinkle pressing force during reverse elongation.

In FIG. 9, the sixth specific example, like the fifth specific example, eliminates the need for a support device for setting the initial position. 36 and check valve 37). Thereby, the proportional electromagnetic relief valve in FIG. 8 can be replaced with a manually adjusted relief valve 145. Similar to FIG. 8, this structure also makes it possible to prevent leakage of pressure medium from between the blank material and the goo when the cylinder 4 is lowered, and to adjust the wrinkle pressing force when the cylinder 4 is extended backwards.

In FIG. 10, this seventh specific example replaces the stroke lower limit setting circuit in FIG. 9 with the check valve 43, button 44, and stroke adjustment screw 45 in FIG. No support device is required.

Similar to FIG. 9, this structure also makes it possible to prevent leakage of pressure medium from between the blank material and the goo when the cylinder 4 is lowered, and to adjust the wrinkle pressing force when the cylinder 4 is extended backwards.

The support device 26 in FIGS. 5 to 7 has a support rod 128 inserted into the pedestal 27 so as to be movable up and down, and the initial position is adjusted by adjusting to a double neck (128). This example shows an example where the arrow is fired upward.

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

A dome forming a fluid pressure chamber containing a pressure medium (fluid) is
It consists of a relatively slidable cylinder and piston, so
During pressure molding with a fluid, there is no need for the pressure medium in the fluid pressure chamber to escape through a throttle valve or the like, and therefore, there is no significant energy loss, no malfunction of the pressure medium, and no temperature rise. This eliminates the need for a pump device or pressure adjustment device for supplying and discharging pressurized fluid for molding, and also eliminates the need to resupply a large amount of pressure fluid, simplifying installation and production cycles. You can expect to improve your time.

Furthermore, in the present invention, when performing reverse stretch forming on a blank material using opposing hydraulic pressure prior to drawing forming using a punch, there is no need to supply a forming pressure medium from the outside to the fluid pressure chamber, and a device for this purpose is not required. , production cycle time is also improved;
The amount of reverse overhang forming can be adjusted accurately using a simple adjustment method, preventing breakage of the blank material or product and extreme reduction in product thickness during drawing forming with a punch, and achieving high quality drawing forming using opposing hydraulic pressure. I can do it.

Since the present invention exhibits the above-mentioned advantages, it is truly significant as a fluid pressure forming processing method and apparatus.

[Brief explanation of the drawing]

The drawings show specific examples of the present invention, and FIGS.
In specific examples, Fig. 1 is an elevational sectional view at the initial position, Fig. 2 is an elevational sectional view showing the pressurized state by the pressure plate, Fig. 3 is an elevational sectional view showing the molding state, and Fig. 4. 1 is an elevational sectional view showing the final stage of the molding process, and FIGS. 5 to 10 are elevational sectional views showing only the main parts of the second to seventh specific examples. ■...Dome, 3...Piston, 4...Cylinder, 5...Dice, 6...Fluid pressure chamber, 8...Punch, 10...Pressure plate, 12...Cylinder Mechanism, 18.
...Control system, 30... Reverse extension amount adjustment means.

Claims (2)

[Claims] (1) A dome 1 having a die 5 and a fluid pressure chamber 6 opened on the die 5 side, and a punch 8 disposed facing the dome 1 so as to be able to enter into the fluid pressure chamber 6 from the die 5 side.
A punch 8 is placed facing the dome 1 and is placed on the dome 1 side.
and a pressure plate 10 that can be pressed independently, and a blank material B having a fluid pressure chamber 6 closed on the die 5.
The blank material B is inserted into the fluid pressure chamber 6 of the punch 8 while the periphery of the die 5 is sandwiched between the dome 1 side and the pressure plate 10 side.
The dome 1 consists of a piston 3 and a cylinder 4, and either the piston 3 or the cylinder 4 is fixed or stationary, and the other is relatively movable. The fluid in the fluid pressure chamber 6 is maintained at a predetermined molding pressure without being discharged from the fluid pressure chamber 6, and furthermore, the fluid pressure chamber 6 is kept closed around the die 5 of the blank material B. is pinched by the cooperation of the dome 1 side and the pressure plate 10, the movable member side of the dome 1 is lowered, and the blank material B is stretched in the opposite direction to the descending direction with a counter liquid, and the amount of reverse stretch molding is 1. A fluid pressure forming processing apparatus characterized by comprising a reverse overhang amount adjusting means 30 for adjusting the amount of reverse overhang. (2) A dome 1 having a die 5 and a fluid pressure chamber 6 opened on the die 5 side, and a punch 8 disposed facing the dome 1 so as to be able to enter into the fluid pressure chamber 6 from the die 5 side.
and a pressure plate 10 that can be pressed independently of the punch 8 on the dome 1 side, which is arranged opposite to the dome 1,
The fluid pressure of the punch 8 is applied to the blank material B while the periphery of the die 5 of the blank material B with the fluid pressure chamber 6 closed on the die 5 is sandwiched between the dome 1 side and the pressure plate 10 side. In the method of drawing with fluid pressure through entry into the chamber 6, either the cylinder 4 or the piston 3 constituting the fluid pressure chamber 6 is fixed or stationary, and the other is relatively movable on the dome 1 side. By lowering the pressure plate 10 while fixing the periphery of the blank material B in cooperation with the pressure plate 10 side, the blank material B is moved in the downward direction of the pressure plate 10 by the opposing hydraulic pressure caused by the fluid in the fluid pressure chamber 6. Reverse stretch molding is performed in the opposite direction, and then the punch 8 is inserted into the die 5 while the periphery of the blank material B is fixed.
Fluid pressure forming is characterized in that drawing forming is performed by opposing hydraulic pressure while pressing the reverse overhang forming part of the blank material B against the outer periphery of the punch 8 through relative movement between the cylinder 4 and the piston 3. Processing method.