JPS6150718B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic press, and particularly to a hydraulic press equipped with a ram device suitable for a hydraulic press.

FIG. 1 is a longitudinal sectional view of a conventionally commonly used hydraulic press.

In the figure, a press body support base 1 consisting of a frame has a workpiece mounting bed 2 fixed to its upper surface to form the basis of the press body. On the upper surface of the bed 2, there is an upright 3 that surrounds the entire circumference.
The crown 4 is placed through the crown 4, and the distance from the bed is kept constant. The crown 4 and the vest 2 are longitudinally tightened and fixed together by two pairs of right and left tie rods 5, 5A, upper nuts 6, 6A, and lower nuts 7, 7A, which pass through the two members. 8 shows the ram device. The cylindrical cylinder 9 is hot-forged integrally with the crown 4 and is arranged so as to protrude upward from the upper surface 4A of the crown 4. On the other hand, a tubular fast-forward cylinder 10 is fixed to the upper inner surface 9A of the cylinder 9 and hangs down. 11 has an upper outer circumference 11A in sliding contact with the inner circumferential surface of the cylinder 9, and an upper inner circumference 11B in sliding contact with the fast-forwarding cylinder 10.
A slide plate 13 is fixed to the lower surface of the hollow piston through a connector 12. The slide plate 13 is held at its four corners by the tie rods 5, 5A via guide bushes 14, 14A, and is configured to move in accordance with the vertical movement of the piston 11.

On the other hand, a rod flange 15 for airtightly holding a hollow piston 11 is attached and fixed to the lower surface of the crown 4, which is the lower surface of the cylinder 9. A hard plate 18 on which a workpiece is placed is fixed on the central upper surface of the bed 2, and a hard plate 18 is similarly installed on the slide plate 13 on the corresponding surface.
9 is buried and fixed.

In such a conventional configuration, when the rapid feed oil P ₁ is pumped through the oil passage R ₁ , the oil fills the hollow portion 11C of the hollow piston 11, and when the internal pressure increases, the hollow piston 11 is rapidly lowered as shown in FIG. Then, since the chamber of the pre-fill valve 16 becomes a negative pressure chamber, the valve 16A opens against the holding spring and oil _P2 from the oil tank 17 is introduced into the pressurizing chamber 9C. Pressurized chamber 9
When C is filled with oil P ₂ , pressurized oil P ₃ is further fed under pressure, and the product is processed by a press operation. When the pressing operation is completed, the oil P ₄ is returned to the outer circumferential space 11D of the hollow piston 11 and the hollow piston 11 begins to return to its original position, and the oil P used for lowering the piston is removed. ₁ , _P2 ,
P ₃ is recovered to its original position via the return route.

In this type of press equipment, considering the operating state of the ram device 8 in Fig. 2, when the hollow piston 11 descends and product processing begins, a reaction force in the direction of arrow W is applied to the hollow piston 11. Increase the internal pressure of the pressure chamber 9C. In other words, a longitudinal tensile stress and a circumferential tensile stress are applied to the cylinder 9 at the same time.

Therefore, in order to have a structure that can withstand this tensile stress and to increase the safety factor, it has been common to design the cylinder 9 to be thick. Further, the nuts 6 and 6A for tightening the tie rods 5 and 5A are arranged on the upper surface of the crown 4 as described above, but since these nuts are arranged outside the maximum outer diameter of the cylinder 9, the nuts 6 and 6A are arranged on the upper surface of the crown 4. The vertical and horizontal lengths of the machine became longer, which naturally increased the installation area of the press, resulting in an increase in the weight of the press machine itself. Incidentally, the increase in the wall thickness of the cylinder and the area of the crown also reduces the rigidity of the crown. For press machines, the rigidity of the crown plays a major role in applying uniformly distributed loads to the workpiece, and if it lacks rigidity, the upper and lower dies will not be horizontal, making it impossible to obtain highly accurate products. Moreover, unnecessary bending stress is applied to the tie rods, the parallelism between the tie rods becomes poor, and mechanical loss due to sliding of the guide plate becomes large.

In the first conventional example, the crown 4 and the cylinder 9 are integrally hot-forged, but
For example, as disclosed in Japanese Patent Publication No. 47-25616, there is also one in which the crown and cylinder are separated and integrally joined. However, in both cases, the cylinder is located above the crown, causing the same problems as described above.

An object of the present invention is to provide a lightweight and highly accurate hydraulic press by arranging the cylinders constituting the ram device so that no tensile stress is applied to them.

The present invention provides a bed for placing a workpiece, a crown disposed at a predetermined distance above the bed, a tie rod device for connecting and fixing the crown and the bed, and a tie rod device that uses hydraulic pressure to connect and fix the crown and the bed. Regarding a hydraulic press comprising a piston that moves up and down, and a ram device that is integrated with the crown and includes a cylinder or the like that houses the piston, the cylinder that constitutes the ram device is attached to the lower surface of the crown. It is fixed. This reduces the tensile stress applied to the cylinder to zero and reduces the area of the crown, resulting in a lightweight and highly accurate hydraulic press.

An embodiment of the present invention will be described below based on the embodiment shown in FIGS. 3 and 4. Components with the same reference numerals as those in FIGS. 1 and 2 have equivalent effects, so detailed explanations will be omitted.

The ram device 20 includes a cylindrical cylinder 22 having a flange portion 22A attached and fixed to the lower surface of a crown 21 made of a flat plate with screws 21, 21A, and an upper outer peripheral portion 11A movable upward and downward on the inner peripheral surface of the cylinder.
a hollow piston 11 in sliding contact with the piston 11;
It is composed of a rapid feed cylinder 10 that hangs down into the hollow portion 11C and is fixed to the lower surface of the crown. Naturally, the joint surfaces of each component are sealed to form an airtight structure. On the other hand, the oil passages R ₁ to _{R 3} are formed using the thickness of the crown 21, respectively. In such a configuration,
The lowering of the hollow piston 11 is similar to the conventional example described above, when the rapid feed oil P1 is supplied from the oil passage _R1 , the hollow piston ₁₁ quickly lowers to the specified position, and the pressurizing chamber 22C is filled with oil. Thereafter, pressurized oil P ₃ is supplied from oil path R ₃ and is used for product processing. This state is shown in FIG.

That is, when the pressurized oil _P3 is supplied and the product processing pressurization W is applied, the internal pressure of the pressurizing chamber 22C increases. At this time, the stress in the vertical direction is applied to the lower end inner peripheral part 22D of the cylindrical cylinder 22 and the upper end outer peripheral part 11A of the hollow piston 11.
Since there is a gap G between them, no tensile stress is applied to the cylindrical cylinder 22. Of course, during product processing, the gap G never becomes zero, so no tensile stress is applied to the cylinder.

As described in the above embodiment, the crown 21 and the cylinder 22 are separated, and the upper surface of the cylinder 22 is butted against the lower surface of the crown 21 and fixed, so that the cylinder 22 has no longitudinal direction when pressurizing the product. Therefore, there is no need to increase the wall thickness of the cylinder 22 itself. Also, since the cylinder has a thin wall and is located on the underside of the crown, it does not get in the way when tightening the tie rod with a nut, and the top area of the crown can be reduced. Therefore, it is possible to provide a press machine that is compact, lightweight, has high rigidity, and has high processing accuracy.

Here, to give a concrete comparison with conventional equipment, it is possible to reduce the cylinder wall thickness by approximately 30%, so the machine weight can be reduced to 1/2 to 1/3 of that of conventional equipment, especially in large-capacity hydraulic presses. can be reduced to
For example, as shown in FIG. 5 for comparison, a 400 (t) press results in a weight reduction of approximately 14 (t).

Furthermore, since the ram device is made up of simple parts, it can be easily machined and has high productivity. Furthermore, since the oil supply passage is formed in the separately formed crown, it is extremely easy to attach and detach from the processing machine and transport it, making it easy to handle.

In the first embodiment, the crown and cylinder are separated, but the same effect can be achieved even if the crown and cylinder are integrally formed as a single part and the cylinder is placed facing downward. can get. In this case, it is desirable to separate the lower end of the cylinder and fix it after installing the piston.

As described above, according to the present invention, a lightweight and highly accurate hydraulic press can be provided.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional hydraulic press, Fig. 2 is a sectional view showing the operating state of the ram device in Fig. 1, and Fig. 3 is a sectional view of a hydraulic press in an embodiment of the present invention. , FIG. 4 is a sectional view showing the operating state of the ram device of FIG. 3, and FIG. 5 is a comparison diagram of the weight of the press bodies of the conventional product and the product of the present invention. 20... Ram device, 21... Crown, 22...
...Cylindrical cylinder, R ₁ , R ₂ , R ₃ ... Oil passage.

Claims (1)

[Scope of Claims] 1. A bed for placing a workpiece, a crown disposed at a prescribed distance above the bed, a tie rod device for connecting and fixing the crown and the bed, and a In a hydraulic press comprising a piston that moves up and down due to pressure, and a ram device that is integrally connected to the crown and includes a cylinder or the like that houses the piston, the ram device is located on the lower surface of the crown. A hydraulic press with the following characteristics. 2. The hydraulic press according to claim 1, wherein the crown is made of a flat plate, and the upper surface of a cylindrical cylinder is butted and fixed to the lower surface of the crown. 3. The hydraulic press according to claim 1, wherein the crown is provided with a conduit for pumping liquid.