JPH0632874B2 - Hydraulic press - Google Patents

Description

TECHNICAL FIELD The present invention relates to improvements in hydraulic presses.

[Prior Art] Various means are used to increase the stroke speed per unit time of a hydraulic press to improve productivity.
For example, one that uses a working shaft pump as a large capacity for high-speed supply of hydraulic oil, one that uses a combination of a high-pressure hydraulic oil pump and a small-diameter cylinder to raise and lower the ram at high speed, and one that uses a so-called double pump to supply hydraulic oil. There is.

[Problems to be Solved by the Invention] Each of the means for increasing the stroke speed has a problem. That is, if the hydraulic pump has a large capacity, the equipment cost including the auxiliary equipment becomes extremely high. In addition, the combination of a high pressure pump and a small diameter cylinder causes a lot of noise and a large impact at the time of pressing, and a drive motor often requires a high output. Further, in the double pump type, the stroke speed easily fluctuates due to the weight of the press load and the pump itself is expensive. In addition to these difficulties, any of the means has a low accuracy of stopping the ram up and down. This is because the viscosity is easily affected by the change in the oil temperature of the hydraulic oil, and the stop position changes due to the variation in the operation timing of the control electric circuit.

The present invention was created in view of the above conventional problems,
An object of the present invention is to provide a hydraulic press that can obtain a high stroke speed even with an oil pump having a low discharge pressure and a low capacity, and that has improved stopping accuracy at upper and lower limit points of a ram.

[Means for Solving the Problems] In order to achieve the above object, the present invention is a ram that is integrally molded with a small-diameter portion that is vertically provided and that is vertically movable in a cylinder. And a pressure chamber for introducing hydraulic oil separately formed between the small diameter portion and the large diameter portion of the ram above and the cylinder, and an operation formed by being formed between the small diameter portion of the ram below and the cylinder. A pressure chamber for introducing oil is provided, and in the vicinity of the upper limit point and the lower limit point of the ram, the hydraulic oil discharge oil passage is blocked and closed by passing up and down the large diameter portion of the ram to gradually reduce the flow rate to zero. The upper and lower inner diameter enlarging portions formed on the inner surface were provided to form a hydraulic press.

[Operation] As described above, the small-diameter portion is fitted in the cylinder, the small-diameter portion is projected on the upper portion of the ram, and separate pressure chambers are formed in the small-diameter portion and the large-diameter portion. If the hydraulic oil is supplied only to the pressure chambers, the rapid feed is lowered, and when the load increases, the hydraulic oil is also supplied to the large diameter pressure chambers to lower the ram with high output. Then, until approaching the vicinity of the lower limit point of the ram, the hydraulic oil in the pressure chamber in the small diameter portion on the ram lower side is rapidly discharged from the enlarged inner diameter portion below the inner peripheral surface of the cylinder in accordance with the rapid feed descent. After the large diameter portion of the ram has passed through this enlarged inner diameter portion to block and block the hydraulic oil discharge oil passage, the hydraulic oil in the remaining pressure chamber has no discharge passage, so the ram uses the hydraulic oil as a cushioning material. Make a sudden stop. As a result, the ram descending speed near the lower limit point gradually decreases and the stopping speed becomes low, and the stopping accuracy is significantly improved.

On the other hand, when the ram rises, the hydraulic oil is introduced into the pressure chamber having a small cross-sectional area formed between the small diameter portion on the lower side of the ram and the cylinder, and the ram rapidly rises, so-called a quick return operation. When the large diameter portion of the ram finishes passing through the enlarged inner diameter portion of the inner surface of the upper cylinder, the speed gradually decelerates and rises, and when the large diameter portion of the ram passes through this enlarged inner diameter portion, the hydraulic oil discharge passage is blocked and blocked. Similar to the above, a rapid stop using hydraulic oil as a cushioning material is reached.

This gradually reduces the ram rising speed near the upper limit point and stops after a low speed, and the stopping accuracy is significantly improved.

Embodiment An embodiment of the hydraulic press of the present invention will be described below with reference to the drawings. FIG. 1 is an overall explanatory view of the hydraulic press of the present invention, and FIG. 2 is a configuration diagram of the essential parts, that is, a ram, a cylinder and a hydraulic oil system.

The hydraulic press of this embodiment was applied to the turret type punch press 1. Inside the frame 3 formed in C shape, the upper mold 5
Various combinations of the lower mold 7 and the lower mold 7 are mounted on the upper turret table 9 and the lower turret table 11, respectively. The upper and lower turret tables 9 and 11 are rotatably supported on the frame 3 via vertical shafts 13 and 15, respectively. The vertical shafts 13 and 15 are synchronously rotated by a counter shaft 17 arranged vertically in the rear portion of the frame 3 via chain transmission mechanisms 19 and 21 composed of sprocket wheels and roller chains. Counter shaft 17 is frame 3
It is driven and rotated by a geared motor 23 incorporated therein via a chain transmission mechanism 25.

As described above, the rotation of the geared motor 23 causes a desired combination of the upper and lower dies 5 and 7 on the upper and lower turret tables W9 and 11 to come directly below the striker 29 below the ram 27 and stop. The ram 27 moves up and down in the cylinder 31, but the cross-sectional shape thereof is as shown in FIG. That is, the small-diameter portions 35 and 37 projecting vertically are integrally formed with the large-diameter portion 33 near the center of the ram 27. Further, separate pressure chambers 3 are provided on the cylinder 31 side facing the upper surface of the ram large diameter portion 33 and the upper surface of the upper small diameter portion 35 of the ram 27, respectively.
9, 41 are formed. Hydraulic oil is introduced into and discharged from the pressure chambers 39 and 41, respectively, between the pressure chambers 39 and 41 and the later-described operating shaft supply system.

On the other hand, a pressure chamber 43 is also formed in the outer peripheral surface portion of the small diameter portion 37 below the large diameter portion 33 of the ram, between the inner peripheral surface of the cylinder 31 and the outer peripheral surface portion of the small diameter portion 37 which are spaced apart from and face each other. The inner diameter of the cylinder 31 in this portion is the same as the outer diameter of the ram large diameter portion 33.
The actuating shaft is introduced into and discharged from the pressure chamber 43 as described above. Then, in the cylinder 31, just before and below the point where the ram 27 rises and falls the most, the so-called upper and lower limits,
Enlarged inner diameter portions 45 and 47 having an annular cross section are provided above and below the inner wall of the cylinder 31 so that the hydraulic oil discharge passage is blocked and blocked by the passage of the ram large diameter portion 33. Therefore, the inner diameter enlarged portions 45 and 47 are respectively formed in the upper large diameter side pressure chamber 3
9 and a part of the lower small diameter side pressure chamber 43.

After the ram large-diameter portion 33 passes through the inner diameter enlarging portions 45 and 47 to block and block the hydraulic oil discharge passage, the residual hydraulic oil in the pressure chambers 39 and 43 connected to these is supplied to the hydraulic oil described later. The check valves 49 and 51 provided in the system cannot discharge the gas. Therefore, the ram 27 uses the hydraulic oil as a cushioning material near the upper and lower limit points, and the hydraulic oil supply system uses an oil tank 53,
Oil pump 55, suction pipe 5 with strainer
7, a discharge side relief valve 59, a solenoid type three-stage electromagnetic switching valve 61, and various pipes including a check valve, etc. The details of the pipes, valves, etc. will be described below together with their operation.

The hydraulic oil pumped up from the oil tank 53 by the oil pump 55 passes through the X path portion on the right side of FIG. 2 of the solenoid valve 61, the descending drive pipe 63, and the pressure chamber 41 of the ram upper small diameter portion 35 (so-called quick approach portion). Is supplied to. With this, the ram 27 starts to descend, but the pressure chamber 41 has a small diameter, so that the rapid feed descends. As the ram 27 descends, the pressure chamber 39 on the upper surface of the ram large-diameter portion 33 expands to a negative pressure, and the working oil is sucked and introduced into the pressure chamber 39 from the oil tank 53 through the suction pipe 65 and the check valves 67 and 69. . Suction pipe 65
In the vicinity of the input of the pressure chamber 39, there are two lines to accelerate suction introduction.

When a striker 29 (see FIG. 1) attached to the lower end of the ram 27 comes into contact with the upper die 5 and a load is applied, hydraulic oil is also supplied from the check valve 49 and the pressure in the pressure chamber 39 rises, so that the check valve 67 and 69 are closed. On the other hand, hydraulic oil continues to flow into the pressure chamber 41 on the ram upper small diameter portion 35, and when the load further increases and the pressure in the pressure chamber 41 rises, the pressure in the lowering drive pipe 63 also rises.

As a result, although the descending speed of the ram 27 is reduced, the total cross-sectional area of the pressure chambers is increased at once, and the upper die 5 is pressed through the striker 29 much more cooperatively than before, and press working is performed.

Until the ram 27 continues to descend and the ram large-diameter portion 33 passes through the inner diameter enlarging portion 47 below the cylinder 31 to block and block the hydraulic oil discharge passage, the hydraulic oil in the pressure chamber 47 at this portion is Is discharged as. That is, the oil is discharged from the flow path 73 provided on the side surface of the inner diameter enlarged portion 47 to the oil tank 53 via the ascending drive pipe 75 and the electromagnetic valve 61. And the ram large diameter portion 33
After passing through the cylinder inner diameter enlarging portion 47 and blocking and closing the hydraulic oil discharge passage, the hydraulic oil in the lower portion of the pressure chamber 43 in a small range therebelow is prevented from being discharged by the check valve 51. Use as a buffer to stop at the correct lower limit level.

When the ram 27 moves up, it operates almost in the opposite manner. That is, the electromagnetic valve 61 uses the path on the left side in FIG. Thus, the hydraulic fluid discharged from the oil pump 55 passes through the solenoid valve 61, the ascending drive pipe 75, the check valve 51, and a small passage resistance to be introduced into the pressure chamber 43. Pressure chamber 4
3 has a thin annular cross section as shown in FIG. 2, and the rising speed is fast. On the other hand, a hydraulic oil discharge hole 77 is provided at the center of the small diameter portion 35 on the ram upper side from the outer peripheral surface of the ram large diameter portion 33 with a check valve 79 interposed. Therefore, the ram large diameter portion 33
Until the oil passes through the upper inner diameter enlarged portion 45 on the inner circumference of the cylinder and shuts off the discharge hole 77 provided with the check valve 79, the hydraulic oils of the pressure chamber 39 and the pressure chamber 41 pass through the inside of the descending drive pipe 63 without resistance. It is made to flow back and is returned to the oil tank 53 via the solenoid valve 61. Therefore, the rising speed of the ram is high up to this point, and so-called fast return operation is performed.

Next, when the ram large-diameter portion 33 rises and passes through the inner diameter enlarging portion 45 and the discharge hole 77 is blocked and closed, the hydraulic oil slightly left on the uppermost portion on the pressure chamber 39 side is not discharged at all and the hydraulic oil is used as a cushioning material. Ram 27 will stop at its high point level.

The intermediate portion of the solenoid valve 61 shown in FIG. 2 is a so-called neutral point, and at this position, the oil discharged from the oil pump 55 returns to the oil tank 53.

Since the hydraulic press of the present invention operates as described above, fast-forwarding and fast-returning operations can be performed with a small-capacity oil pump under conditions where a press load is not applied. Then, under the condition that a press load is applied, the lowering operation is applied by the pressure chamber 39 having a large cross-sectional area, so that a large press pressure can be exerted even with an oil pump having a low discharge pressure. Further, the ascending / descending speed of the ram 27 is gradually reduced near the upper and lower limit points of the ram 27, and the stop position accuracy can be remarkably improved in the shielding closed state. Therefore, there is no time loss in the press work, the number of strokes per unit time can be increased, and the press capacity can be sufficiently increased. Furthermore, the stopping accuracy is also very good. As a result, high-productivity and high-quality press working becomes possible. In addition, it can be implemented without significantly increasing equipment costs and device shape.

The hydraulic press of the present invention is not limited to the one embodiment described above, and various modifications and applications are possible. Further, the hydraulic oil discharge hole 77 and the check valve 79 provided in the ram large diameter portion 33 may be provided as an external pipe from a hole penetrating from the enlarged inner diameter portion 45 on the cylinder 31 side to the outside. Further, the hydraulic press of the present invention is widely used in various hydraulic presses other than the turret punch press. Further, it is easy to apply the present invention by replacing the existing cylinder and ram of the hydraulic press with those of the constitution of the present invention, and the present invention can be widely applied.

[Effect] As is clear from the above description, according to the hydraulic press of the present invention, it is possible to perform a press work with a high stroke number per unit time without making the oil pump having a particularly large capacity or high pressure, and further, to move the ram up and down. The stopping accuracy at each limit point is improved. Therefore, stable press processing with high productivity and high quality can be performed.

[Brief description of drawings]

FIG. 1 is an external side view of an embodiment of the hydraulic press of the present invention,
FIG. 2 shows a configuration diagram including the main part and a hydraulic oil system. Description of main drawing symbols 1 …… Turret punch press (hydraulic press) 27 …… Ram, 31 …… Cylinder 35 …… (Upper) small diameter part, 37 …… (Lower) small diameter part 39 …… (Upper large diameter) Side) Pressure chamber 41 …… (Upper small diameter side) Pressure chamber 43 …… (Lower small diameter side) Pressure chamber 45 …… (Upper) Inner diameter expansion part 47 …… (Lower) Inner diameter expansion part 49 …… (Upper) check Valve 51 …… (Lower side) Check valve

Claims (1)

[Claims] 1. A ram which is integrally formed with a small-diameter portion which is provided so as to project vertically, and which is fitted in a cylinder so as to be movable up and down.
Pressure chambers are formed separately between the small diameter portion and the large diameter portion on the ram upper side and the cylinder, respectively, and pressure chambers for introducing the working oil are provided, and the working oil is formed between the small diameter portion on the ram lower side and the cylinder. A pressure chamber for introducing the oil is provided, and in the vicinity of the upper limit point and the lower limit point of the ram, the hydraulic oil discharge oil passage is blocked and closed by the up and down passage of the large diameter portion of the ram, so that the inner surface of the cylinder is gradually reduced to zero. A hydraulic press characterized in that it is provided with upper and lower inner diameter enlarging portions formed.