JP2003161306A - Double-acting hydraulic cylinder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a remarkable double-acting hydraulic cylinder capable of simplifying and reducing the structure in size and weight by adopting an automatic change-over valve structure assembled in the cylinder without using a conventional solenoid valve or a manual change-over valve. <P>SOLUTION: In the double-acting hydraulic cylinder comprising a piston 3 movable against a return spring 2 by pressurizing with pressurized oil fed to a cylinder 1, a first valve lever acting mechanism and a second valve lever mechanism in the piston 3, the communicating state of working fluid is formed so as to be switched corresponding to the reciprocation of the piston 3. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-acting hydraulic cylinder used as punch operating means for a punching machine or the like.

[0002]

2. Description of the Related Art Conventionally, a portable punching machine as shown in FIG. 1 has been widely used.

To briefly explain this punching machine, an electric motor is provided above the machine body A, a hydraulic pressure generating mechanism for generating hydraulic pressure by the operation of the electric motor is provided in the machine body A, and the machine body A below the hydraulic pressure generating mechanism is provided. A hydraulic actuator 26 (piston / cylinder mechanism) that moves up and down by the hydraulic pressure of the hydraulic pressure generating mechanism is provided, and a punch 27 is provided at the lower end of the piston 2 of the hydraulic actuator 26. The hole is punched in the material to be punched 29 in cooperation with the die 28 provided at the base of the.

Further, conventionally, a double-acting hydraulic cylinder has been generally adopted as the hydraulic actuator 26 for moving the punch.

Explaining the double-acting hydraulic cylinder, a piston is movably provided in a cylinder formed in the main body of the apparatus, and an oil tank and a cylinder chamber opposed to each other with the piston interposed therebetween are provided with pipes for supplying and discharging oil. A structure is provided in which a pump is connected to this pipeline via a four-port switching type solenoid valve.

When the solenoid valve is operated such that the pump is operated to supply the oil from the pipe to the oil tank chamber, the piston tip portion is retracted to the cylinder due to the increase in the oil pressure in the oil tank chamber, When the solenoid valve is operated so that oil is supplied to the cylinder chamber, the hydraulic pressure in the cylinder chamber increases so that the tip of the piston moves out of the cylinder.

Therefore, according to the punching machine which employs this double-acting hydraulic cylinder, the piston is double-actuated by the switching of the solenoid valve, and the leading end portion moves in and out. Performs reciprocating motion, and perforated material 29
Can be drilled into.

However, in the conventional punching machine using the double-acting hydraulic cylinder, it is difficult to reduce the size and weight of the punching machine because the solenoid valve has a complicated structure. However, there was a problem that it became large.

In view of such a problem, the present invention is to solve the problem, and an automatic switching valve structure incorporated in a cylinder is used without using a solenoid valve or a manual switching valve. (EN) An epoch-making double-acting hydraulic cylinder that can be simplified and reduced in size and weight.

[0010]

The gist of the present invention will be described with reference to the accompanying drawings.

A piston 3 which is pressed by pressure oil fed into the cylinder 1 and is movable against the return spring 2,
A first conduction hole 6 and a second conduction hole 7 which are provided in the piston 3 and communicate with the oil tank chamber 5 on the opposite side of the cylinder chamber 4;
A first valve rod 8 movably provided in the first conduction hole 6 to open and close the first conduction hole 6 by movement, and the second conduction hole 7
A second valve rod 9 that is movably provided to open and close the second conduction hole 7 by movement, an oil feed path 10 that feeds pressure oil to the first conduction hole 6, and a pressure from the second conduction hole 7. An oil discharge path 11 for discharging oil, and the pressure oil discharged from the oil discharge path 11 by connecting the oil supply path 10 and the oil discharge path 11 by means of the pressure supply means 13 When the piston 3 is located on the cylinder chamber 4 side and the pressure oil circulation route 12 that circulates and introduces into the cylinder 1 through the cylinder chamber 4, the oil feeding route 10 is connected through the first conduction hole 6 to the cylinder chamber 4 When the piston 3 is moved to the oil tank chamber 5 side while the first communication hole 6 and the oil tank chamber 5 are in a closed state while communicating with the oil communication path 10, So that the oil tank chamber 5 is in communication with the first communication hole 6 and the cylinder chamber 4 is closed. A first valve rod actuating mechanism 20 which controls the operation of the first valve rod 8, the piston 3 cylinder chamber 4
In the state of being located on the side, the drain passage 11 is in communication with the oil tank chamber 5 through the second conduction hole 7, the second conduction hole 7 and the cylinder chamber 4 are closed, and the piston 3 When the oil is moved to the oil tank chamber 5 side, the oil drainage path 11 is in communication with the cylinder chamber 4 through the second communication hole 7, and the second communication hole 7 and the oil tank chamber 5 are closed. Second valve rod actuating mechanism for actuating and controlling the second valve rod 9
21 is related to a double-acting hydraulic cylinder.

Further, the first valve rod 8 is provided with the first valve rod 8.
A first seal surface 22 that closes the first conduction hole 6 when the oil is moved to the oil tank chamber 5 side, and a second seal surface 23 that closes the first conduction hole 6 when moved to the cylinder chamber 4 side. When the first sealing surface 22 of the first valve rod 8 closes the first communication hole 6, the oil supply path 10 communicates with the cylinder chamber 4 or the oil tank chamber 5 through the first communication hole 6 when provided. When the second sealing surface 23 closes the first conduction hole 6, the oil feed path 10 is in communication with the oil tank chamber 5 or the cylinder chamber 4 through the first conduction hole 6 A third seal surface that constitutes a rod actuating mechanism 20 and closes the second communication hole 7 when the second valve rod 9 moves to the oil tank chamber 5 side, which constitutes the second valve rod 9.
24 and a fourth sealing surface 25 that closes the second conduction hole 7 when moved to the cylinder chamber 4 side, and the second valve rod 9
When the third sealing surface 24 of the second sealing hole 24 closes the second communicating hole 7, the oil discharge path 11 is in communication with the oil tank chamber 5 or the cylinder chamber 4 through the second communicating hole 7, and the fourth sealing surface 25 When the second passage hole 7 is closed by the second passage hole 7, the second valve rod actuating mechanism 21 is configured so that the oil drainage path 11 is in communication with the cylinder chamber 4 or the oil tank chamber 5 via the second passage hole 7. The present invention relates to the double-acting hydraulic cylinder according to claim 1.

Further, the first valve rod 8 and the second valve rod 9 are provided with cylinder chamber side protrusions 8A and 9A, respectively, which protrude toward the cylinder chamber 4 side, and the oil tank chamber side which protrudes toward the oil tank chamber 5 side. Protrusions 8B and 9B are provided, the piston 3 is located on the cylinder chamber 4 side, and the cylinder chamber-side protrusion 8A of the first valve rod 8 is provided.
When the first valve rod 8 is moved to the oil tank chamber 5 side by directly or indirectly contacting a predetermined position in the cylinder chamber 4, the first sealing surface 22 of the first valve rod 8 is While the first conduction hole 6 is closed, the oil feed path 10 is in communication with the cylinder chamber 4 or the oil tank chamber 5 via the first conduction hole 6, and the piston 3 moves to the oil tank chamber 5 side. In the state where the first valve rod 8 is moved to the cylinder chamber 4 side by the direct or indirect contact of the oil tank chamber side projection 8B of the valve rod 8 with a predetermined position in the oil tank chamber 5, this first valve The second sealing surface 23 of the rod 8 closes the first conduction hole 6, and the oil feed path 10 is in communication with the oil tank chamber 5 or the cylinder chamber 4 through the first conduction hole 6. The one valve rod operating mechanism 20 is constituted, the piston 3 is located on the cylinder chamber 4 side, and the second valve rod 9 is provided. In the state where the second valve rod 9 is moved to the oil tank chamber 5 side by directly or indirectly contacting the cylinder chamber side protruding portion 9A of the cylinder chamber 4 with a predetermined position in the cylinder chamber 4,
The third sealing surface 24 of the second valve rod 9 closes the second conducting hole 7, and the oil drainage passage 11 communicates with the cylinder chamber 4 or the oil tank chamber 5 through the second conducting hole 7. Then, the piston 3 moves to the oil tank chamber 5 side, and the oil tank chamber side protruding portion 9B of the second valve rod 9 directly or indirectly abuts on a predetermined position in the oil tank chamber 5 so that the second valve rod 9 Is moved to the cylinder chamber 4 side, the fourth sealing surface 25 of the second valve rod 9 closes the second conducting hole 7, and the oil drainage path 11 passes through the second conducting hole 7. 3. The double-acting hydraulic cylinder according to claim 2, wherein the second valve rod actuating mechanism 21 is in communication with the oil tank chamber 5 or the cylinder chamber 4.

Further, when the piston 3 is returned, the first valve rod 8 moves toward the cylinder chamber 4 side, and the oil feeding path 10
Is in communication with the oil tank chamber 5 through the first communication hole 6, and the first communication hole 6 and the cylinder chamber 4 are in a closed state, so that the pressure oil is pumped into the oil tank chamber 5. Valve 8
Is provided with a first opening holding mechanism 14 for positioning and holding the movable position of the second valve rod 9, the second valve rod 9 is moved to the cylinder chamber 4 side, and the oil discharge path 11 is provided through the second communicating hole 7 in the cylinder chamber. 4, the second communication hole 7 and the oil tank chamber 5 are closed, and the movable position of the second valve rod 9 through which the pressure oil in the cylinder chamber 4 is discharged to the oil discharge path 11 is maintained. A double-acting hydraulic cylinder according to any one of claims 1 to 3, characterized in that a second open holding mechanism 15 is provided.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION A preferred embodiment of the present invention (how to carry out the invention) will be briefly described with reference to the drawings and showing its function and effect.

The piston 3 is held by the urging force of the return spring 2 in a position closest to the cylinder chamber 4 in the cylinder 1. In this state, the first valve rod actuating mechanism is operated.
The first valve rod 8 is moved by 20 and, for example, the oil feed path 10 is in communication with the cylinder chamber 4 via the first conduction hole 6, and the first conduction hole 6 and the oil tank chamber 5 are closed. ing.

At this time, the second valve rod operating mechanism 21 moves the second valve rod 9 so that the oil drainage path 11 is in communication with the oil tank chamber 5 through the second conduction hole 7 and the second conduction. The hole 7 and the cylinder chamber 4 are closed.

In this state, when pressure oil is pressure-fed from the oil feed path 10 by the pressure feed means 13 of the pressure oil circulation path 12, the pressure oil flows into the cylinder chamber 4 through the first conduction hole 6, and this pressure oil The piston 3 is pressed toward the oil tank chamber 5 by the hydraulic pressure. At this time, the pressure oil remaining in the oil tank chamber 5 flows out to the oil discharge path 11 through the second conduction hole 7 and circulates to the pressure feeding means 13.

Therefore, a pressure difference is generated between the cylinder chamber 4 and the oil tank chamber 5 on the opposite side of the piston 3.
The piston 3 moves in the cylinder 1 against the return spring 2 toward the oil tank chamber 5 side (forward movement), and for example, a working portion (punch 27) provided at the movable tip of the piston 3 performs a working operation.

As the piston 3 moves, the first valve rod 8
And the second valve rod 9 also move, but when the piston 3 moves to the oil tank chamber 5 side, the first valve rod actuating mechanism 20 moves the first valve rod 8 to make the oil feed path 10 first conductive. The first communication hole 6 and the cylinder chamber 4 are in a closed state via the hole 6 and the first communication hole 6 and the cylinder chamber 4 are in a closed state, and pressure oil is pumped into the oil tank chamber 5, and the piston 3 is driven by the oil pressure of the pressure oil. Is pressed toward the cylinder chamber 4 side.

At this time, the second valve rod 9 is moved by the second valve rod actuating mechanism 21 so that the oil discharge passage 11 is in communication with the cylinder chamber 4 through the second communication hole 7 and The second conduction hole 7 and the oil tank chamber 5 are in a closed state, and the pressure oil in the cylinder chamber 4 is discharged to the oil discharge path 11, and the pressure feeding means is provided.
It will cycle to 13.

Further, for example, the piston 3 may be automatically returned to the cylinder chamber 4 side by the restoring force of the return spring 2 without sending the pressure oil into the oil tank chamber 5.

Therefore, the piston 3 moves (returns) in the cylinder 1 to the cylinder chamber 4 side, and pressure oil is pumped to the first valve rod 8 by the pressure feeding means 13, whereby the piston 3 automatically reciprocates. It will be.

In the present invention, the cylinder 1 is thus constructed.
Since the automatic switching valve structure is incorporated therein, the structure is simpler than that of a structure using a solenoid valve or a manual switching valve, and a compact and lightweight double-acting hydraulic cylinder can be configured.

Therefore, for example, if the compact and lightweight double-acting hydraulic cylinder of the present invention is adopted as the hydraulic actuator 26 of the punching machine described in the section of the prior art, it is compact and lightweight and has excellent handleability. It is an epoch-making double-acting hydraulic cylinder with extremely high practicality that enables the construction of a drilling machine.

Further, for example, when the piston 3 is returned, the first valve rod 8 is moved to the cylinder chamber 4 side, and the oil feed path 10 is passed through the first communication hole 6 to the oil tank chamber 5 A first open hold for positioning and holding the movable position of the first valve rod 8 in which the first communicating hole 6 and the cylinder chamber 4 are closed and the pressure oil is pumped into the oil tank chamber 5. A mechanism 14 is provided, and the second valve rod 9 has a cylinder chamber 4
By moving to the side, the oil discharge path 11 is brought into communication with the cylinder chamber 4 through the second conduction hole 7, and the second conduction hole 7 and the oil tank chamber 5 are closed so that the cylinder chamber 4 is closed. If the second opening holding mechanism 15 that positions and holds the movable position of the second valve rod 9 through which the pressure oil inside is discharged to the oil drain passage 11 is provided, the first valve rod 8 will move to the oil tank chamber 5 when the piston 3 returns. Since the state in which the oil supply path 10 is in communication is automatically maintained and the state in which the second valve rod 9 is in communication between the cylinder chamber 4 and the oil discharge path 11 is automatically maintained, it is always stable. It is an excellent double-acting hydraulic cylinder that maintains its returning motion.

[0027]

Embodiments of the present invention will be described with reference to the drawings.

In the present embodiment, the present invention is applied to the hydraulic actuator 26 of the punching machine as shown in FIG. 1, and the description of this punching machine overlaps with the description in the section of the prior art. Therefore omitted.

In this embodiment, a piston 3 is provided which is pressed by pressure oil fed into the cylinder 1 and is movable against the return spring 2. The piston 3 is provided with an oil tank chamber 5 on the opposite side of the cylinder chamber 4. First communication hole 6 and second communication hole 7 communicating with each other
And a first valve rod 8 for closing the first conduction hole 6 is movably provided so that the first conduction hole 6 can be opened and closed by the movement of the first valve rod 8. A second valve rod 9 that closes 7 is movably provided, and the second conduction hole 7 is configured to be openable and closable by the movement of the second valve rod 9.
An oil supply path 10 for sending pressure oil to the cylinder 1 is provided, and an oil discharge path 11 for discharging the pressure oil is provided to the second communication hole 7 and the oil discharge path 11 is connected to the oil supply path 10. A pressure oil circulation path 12 is formed through the pressure oil circulation path 12, and a pressure feeding means 13 is provided in the pressure oil circulation path 12 to force the pressure oil from the oil feeding path 10 to the first conduction hole 6, and the first valve rod 8 and The second valve rod 9 has a cylinder chamber side protruding portion 8A protruding toward the cylinder chamber 4 side, respectively.
9A is provided, and oil tank chamber side projecting portions 8B and 9B projecting to the oil tank chamber 5 side are provided, the piston 3 is located on the cylinder chamber 4 side, and the cylinder chamber side projecting portion 8A of the first valve rod 8 is the cylinder chamber 4 side. When the first valve rod 8 is moved to the oil tank chamber 5 side by coming into contact with a predetermined position therein, the oil feeding path 10 is in communication with the cylinder chamber 4 via the first conduction hole 6 and The one conduction hole 6 and the oil tank chamber 5 are closed so that the pressure oil is pumped into the cylinder chamber 4. At this time, the cylinder chamber side projection 9B of the second valve rod 9 is connected to the cylinder. The second valve rod 9 is brought into contact with a predetermined position in the chamber 4 so that the oil tank chamber 5
By moving to the side, the oil drainage path 11 is moved to the second conduction hole 7
Is in communication with the oil tank chamber 5 through the second communication hole 7
The cylinder chamber 4 and the cylinder chamber 4 are closed so that the pressure oil in the oil tank chamber 5 is discharged to the oil discharge passage 11, and the cylinder chamber 4 is discharged from the oil supply passage 10 via the first conduction hole 6. The piston 3 is configured to move forward by being pressed toward the oil tank chamber 5 side by the pressure oil that is press-fitted therein, the piston 3 moves to the oil tank chamber 5 side, and the oil tank chamber side protrusion 8B of the first valve rod 8 is formed. When the first valve rod 8 is moved to the cylinder chamber 4 side by directly or indirectly contacting a predetermined position in the oil tank chamber 5, the oil feed path 10 is connected to the oil tank via the first conduction hole 6. The first communication hole 6 and the cylinder chamber 4 are in communication with the chamber 5 and the cylinder chamber 4 is in a closed state so that the pressure oil is pumped into the oil tank chamber 5. At this time, the second valve rod 9 is used. And the second valve rod 9 is movable toward the cylinder chamber 4 side by contacting the oil tank chamber side protruding portion 9B of the above with a predetermined position in the oil tank chamber 5. The oil discharge path 11 is in communication with the cylinder chamber 4 through the second communication hole 7, and the second communication hole 7 and the oil tank chamber 5 are in a closed state so that the pressure oil in the cylinder chamber 4 is discharged. The oil tank chamber 5 is configured to be discharged to the oil passage 11 from the oil feed passage 10 via the first conduction hole 6.
The present invention relates to a double-acting hydraulic cylinder, characterized in that the piston 3 is pressed toward the cylinder chamber 4 side by the pressure oil that is press-fitted therein to move back.

A more specific description will be given below.

In this embodiment, the piston 3 provided in the cylinder 1 is formed with a first through hole 6 (through passage), and a retaining chamber 6A is formed in the middle of this through passage. The retaining chamber 6A is located on the oil tank chamber 5 side. A large-diameter through passage 6B that penetrates the oil tank chamber 5 is formed in the above, and a small-diameter through passage 6C is formed in the stationary chamber 6A on the cylinder chamber 4 side.

The first valve rod 8 has a large-diameter closing plate 8C formed in the middle thereof, and the upper rod is a cylinder chamber-side projecting portion 8A in the drawing from the large-diameter closing plate 8C. Part 8C
The lower rod portion is the oil tank chamber side protruding portion 8B. Also,
A cushioning kick spring is provided at the tip of the oil tank chamber side protruding portion 8B.
30 is installed in the fitted state.

Then, the large-diameter blocker portion 8C is arranged in the retaining chamber 6A, and the oil tank chamber-side protruding portion 8B is slidably fitted into the large-diameter through passage 6B to form the cylinder chamber-side protruding portion 8A.
Is slidably inserted into a fitting portion 17 provided on the side of the small diameter through passage 6C. Further, the cylinder chamber side protruding portion 8A is provided so that its tip protrudes toward the cylinder chamber 4 side from the fitting portion 17, and the oil tank chamber side protruding portion 8B also has its tip at the large diameter through passage 6.
It is provided so as to project to the oil tank chamber 5 side from B.

Further, in this embodiment, the piston 3 is provided with the second through hole 7 (through passage), and the stopping chamber 7 is provided in the middle of this through passage.
A is formed, and the oil tank chamber 5 is formed on the oil tank chamber 5 side of the stopping chamber 7A.
A small diameter through passage 7B is formed so as to penetrate therethrough, and a large diameter through passage 7C is formed on the cylinder chamber 4 side of the stopping chamber 7A.

The second valve rod 9 has a large-diameter portion formed at the upper end and the lower end in FIG. 2, the upper-side large-diameter portion serving as the cylinder chamber-side protruding portion 9A, and the lower-diameter portion serving as the oil tank chamber side. It is a protruding part.

The intermediate rod portion of the second valve rod 9 is slidably fitted into the retaining chamber 7A and the small diameter through passage 7B, and the large diameter cylinder chamber side projection 9A is disposed in the large diameter through passage 7C. In addition, the large-diameter oil tank chamber-side protruding portion 9B is disposed below the small-diameter through passage 7B and exposed to the outside of the second conduction hole 7.
Further, the cylinder chamber side protruding portion 9A is provided so that its tip protrudes toward the cylinder chamber 4 side from the large diameter through passage 7C.

In this embodiment, an oil feed path 10 for sending pressure oil to the retaining chamber 6A of the first conducting hole 6 is provided in communication with the retaining chamber 6A, while the small diameter through passage of the second conducting hole 7 is provided. 7
This small diameter through passage 7B
Is connected to the oil supply path 10 and the oil discharge path 11 to connect the pressure oil discharged from the oil discharge path 11 with pressure.
A pump device as 13 constitutes a pressure oil circulation path 12 which circulates and introduces into the cylinder 1 through the oil supply path 10 and the first conduction hole 6. Reference numeral 33 in the figure is an oil tank.

Further, in the present embodiment, when the piston 3 is located on the cylinder chamber 4 side, the oil feed passage 10 is in communication with the cylinder chamber 4 through the first conduction hole 6, and In the state where the one conduction hole 6 and the oil tank chamber 5 are closed and the piston 3 is moved to the oil tank chamber 5 side,
The oil feed path 10 is in communication with the oil tank chamber 5 through the first conduction hole 6, and the first valve rod 8 is operated and controlled so that the first conduction hole 6 and the cylinder chamber 4 are closed. A first valve rod actuating mechanism 20 is provided.

This first valve rod mechanism 20 is the same as the first valve rod 8 described above.
First, when the first valve rod 8 moves to the oil tank chamber 5 side, the first sealing surface 22 that closes the first conduction hole 6 and the cylinder chamber 4
Second sealing surface that closes the first conduction hole 6 when moved to the side
23 is provided, and when the first sealing surface 22 of the first valve rod 8 closes the first conduction hole 6, the oil feed path 10 is in communication with the cylinder chamber 4 through the first conduction hole 6. When the second sealing surface 23 closes the first conduction hole 6, the oil feed path 10 is in communication with the oil tank chamber 5 via the first conduction hole 6.

More specifically, the first sealing surface 22 is
This is the lower surface of the large-diameter closing plate portion 8C, and when the first valve rod 8 is moved to the oil tank chamber 5 side, the first sealing surface 22 is the stop chamber 6A.
6A and the oil tank chamber 5 are closed by making contact with the bottom surface of the oil storage chamber 6 and at the same time, the stationary chamber 6A and the oil feed passage 10 are in communication with each other, and the oil feed passage 10 is connected to the stationary chamber 6A and the small diameter through passage 6C. The pressure oil can flow into the cylinder chamber 4 via the.

The second sealing surface 23 has a large-diameter closing plate portion 8
As the upper surface of C, when the first valve rod 8 moves to the cylinder chamber 4 side, the second sealing surface 23 contacts the upper surface of the retaining chamber 6A to close the retaining chamber 6A and the cylinder chamber 4. ,
At this time, the stationary chamber 6A and the oil supply path 10 are in communication with each other, and the pressure oil can flow from the oil supply path 10 into the oil tank chamber 5 through the stationary room 6A and the large diameter through passage 6B.

Further, in the present embodiment, when the piston 3 is located on the cylinder chamber 4 side, the oil drain passage 11 is in communication with the oil tank chamber 5 through the second conduction hole 7, and When the second conduction hole 7 and the cylinder chamber 4 are closed, and the piston 3 is moved to the oil tank chamber 5 side,
Operation control of the second valve rod 9 is performed so that the oil drainage passage 11 is in communication with the cylinder chamber 4 through the second conduction hole 7 and the second conduction hole 7 and the oil tank chamber 5 are closed. A second valve rod operating mechanism 21 is provided.

The second valve rod actuating mechanism 21 has a third sealing surface on the second valve rod 9, which closes the second conducting hole 7 when the second valve rod 9 moves to the oil tank chamber 5 side. 24, and a fourth sealing surface that closes the second conduction hole 7 when moved to the cylinder chamber side
25 is provided, and when the third sealing surface 24 of the second valve rod 9 closes the second communication hole 7, the oil discharge path 11 is in communication with the oil tank chamber 5 through the second communication hole 7, The fourth sealing surface 25
When the second conduction hole 7 is closed, the oil drainage path 11 is in communication with the cylinder chamber 4 via the second conduction hole 7.

More specifically, the third sealing surface 24 is
This is the lower surface of the large-diameter cylinder chamber side protruding portion 9A, and when the second valve rod 9 moves to the oil tank chamber 5 side, this third sealing surface 24
Comes into contact with the bottom surface of the large diameter through passage 7C to close the stationary chamber 7A and the cylinder chamber 4, and at this time, the stationary chamber 7A and the oil discharge passage 11 are in communication with each other through the small diameter through passage 7B. The pressure oil in the oil tank chamber 5 is allowed to flow out from the oil discharge route 11 via the small through passage 7B and the stopping chamber 7A.

The fourth sealing surface 25 is the upper surface of the large-diameter oil tank chamber-side protruding portion 9B, and the first valve rod 8 is the cylinder chamber 4
When it moves to the side, the fourth sealing surface 25 abuts the peripheral surface portion below the small diameter through passage 7B to close the small diameter through passage 7B and the oil tank chamber 5, and at the same time the small diameter through passage 7B and the drainage passage are discharged. The oil passage 11 is in communication with the oil passage 11, and the pressure oil in the cylinder chamber 4 can flow out from the oil discharge passage 11 through the small diameter through passage 7B, the stopping chamber 7A, and the large diameter through passage 7C.

Further, in this embodiment, when the piston 3 returns, the first valve rod 8 moves toward the cylinder chamber 4 side,
The oil feed path 10 is in communication with the oil tank chamber 5 through the first communication hole 6, and the first communication hole 6 and the cylinder chamber 4 are in a closed state, so that pressure oil is stored in the oil tank chamber 5. A first open holding mechanism 14 is provided for positioning and holding the movable position of the first valve rod 8 that is pumped.

More specifically, the lateral hole 31 is formed in the fitting portion 17 into which the cylinder chamber side protruding portion 8A of the first valve rod 8 is fitted (fitted).
A coil spring as an elastic body 19 is provided in the lateral hole 31, and a ball-shaped engagement member is urged by the coil spring 19 toward the peripheral surface of the first valve rod 8 (cylinder chamber side protruding portion 8A). A united body 18 is provided.

That is, the coil spring 19 causes the ball-shaped engagement body 18 to press and contact the cylinder chamber side projection 8A of the first valve rod 8. On the other hand, when the first valve rod 8 moves on the circumferential surface of the cylinder chamber side protruding portion 8A, this engaging body 18 is fitted and engaged, and when the first valve rod 8 is movable back, it is possible to get over and disengage. The concave engaging portion 16 is formed.

Further, the structure of the first open holding mechanism 14 adopted in this embodiment is a simple structure, very easy to manufacture, and excellent in mass productivity.

Further, in this embodiment, the second valve rod 9 is moved to the cylinder chamber 4 side so that the oil drainage passage 11 is in communication with the cylinder chamber 4 through the second conduction hole 7. The second opening holding mechanism 15 for positioning and holding the movable position of the second valve rod 9 in which the second communication hole 7 and the oil tank chamber 5 are closed and the pressure oil in the cylinder chamber 4 is discharged to the oil discharge path 11. Is provided.

Specifically, a coil spring as an elastic body 32 having anti-compression elasticity is fitted on the intermediate rod portion of the second valve rod 9, and one end (upper end in FIG. 2) of this coil spring 32 is a large cylinder. While contacting the lower surface of the chamber-side projecting portion 9A and contacting the other end (lower end) of the coil spring 32 with the lower surface of the retaining chamber 7A, the second valve rod 9 is moved to the cylinder by the anti-shrinking force of the coil spring 32. It is urged toward the chamber 4 so that the oil drainage path 11 is kept in communication with the cylinder chamber 4 through the second conduction hole 7 and the second conduction hole 7 and the oil tank chamber 5 are closed. It is configured to be.

Further, the structure of the second opening holding mechanism 15 used in this embodiment is also a simple structure, which is very easy to manufacture and is excellent in mass productivity.

Further, in the present embodiment, a pressing portion 8D is provided in the middle of the oil tank chamber side protruding portion 8B of the first valve rod 8 toward the second valve rod 9, and the pressing portion 8D is the first portion. The two valve rods 9 are provided so as to be located below the oil tank chamber-side protruding portion 9B, and the oil tank chamber-side protruding portion 8B of the first valve rod 8 is brought into contact with a predetermined position of the oil tank chamber 5 via the kick spring 30. When the first valve rod 8 moves to the cylinder chamber 4 side, the pressing portion 8D moves the second valve rod 9 at this time.
The oil tank chamber side protruding portion 9B is pushed toward the cylinder chamber 4 side, and as a result, the second valve rod 9 is moved to the cylinder chamber 4 side together with the first valve rod 8.

That is, in this embodiment, when the piston 3 moves (forward) to the oil tank chamber 5 side and reaches the forward end point position, the oil tank chamber side protrusion 9B of the second valve rod 9 is moved to the first position. It is configured to indirectly contact a predetermined position (bottom wall surface) in the oil tank chamber 5 via the pressing portion 8D of the valve rod 8.

Next, the operation of this embodiment will be described.

Normally, the piston 3 is held by the urging force of the return spring 2 at a position closest to the cylinder chamber 4 in the cylinder 1 (forward movement starting point position). In this state, the first valve rod 8 is held. When the cylinder chamber side protruding portion 8A of the cylinder contacts the predetermined position (top wall surface) in the cylinder chamber 4, the first valve rod 8 is moved to the oil tank chamber 5 side, and the oil feed path 10 is connected to the first conduction hole 6 It is in communication with the cylinder chamber 4 through (the stop chamber 6A and the small diameter passage 6C), and the first communication hole 6 (large diameter passage 6B) and the oil tank chamber 5 are closed (see FIG. 2). .

At this time, the cylinder chamber side projection 9A of the second valve rod 9 is brought into contact with a predetermined position (top wall surface) in the cylinder chamber 4 to resist the urging force of the elastic body 32. Valve 9
Moves to the oil tank chamber 5 side, and the oil drainage path 11 moves to the second conduction hole 7
The oil tank chamber 5 is communicated with the small diameter through passage 7B, and the second communication hole 7 (small diameter through passage 7B / retaining chamber 7A) and the cylinder chamber 4 are closed (see FIG. 2).

In this state, when pressure oil is pressure-fed from the oil feed path 10 by the pressure feeding means 13, the pressure oil flows into the cylinder chamber 4 through the first communicating hole 6, and the piston 3 is driven by the oil pressure of this pressure oil. Is pressed toward the oil tank chamber 5. At this time, the pressure oil remaining in the oil tank chamber 5 flows out to the oil discharge path 11 through the second conduction hole 7 and circulates to the pressure feeding means 13.

Therefore, a pressure difference is generated between the cylinder chamber 4 and the oil tank chamber 5 on the opposite side of the piston 3.
As shown in FIG. 3, the piston 3 moves (forward) to the oil tank chamber 5 side against the return spring 2 in the cylinder 1, and, for example,
Processing work is performed by the processing section (punch 27) provided at the movable tip of the piston 3.

As the piston 3 moves, the first valve rod 8
And the second valve rod 9 also move, but when the oil tank chamber side protruding portion 8B of the first valve rod 8 comes into contact with a predetermined position (bottom wall surface) in the oil tank chamber 5, the first valve rod 8 is moved to the cylinder chamber. It moves to the 4th side and the oil supply path 10 is switched so as to be in communication with the oil tank chamber 5 via the first conduction hole 6, and the first conduction hole 6 and the cylinder chamber 4 are closed. Pressure oil is pumped into the oil tank chamber 5. At this time, the engaging body 18 is engaged with the engaging portion 16, and the oil feed path 10 is in communication with the oil tank chamber 5 through the first conduction hole 6 and the first conduction hole 6 and the cylinder chamber 4 is closed and the movable position of the first valve rod 8 to which the pressure oil is pumped into the oil tank chamber 5 is positioned and held (see FIG. 4).

At this time, when the protruding portion 9B on the oil tank chamber side of the second valve rod 9 comes into contact with the pressing portion 8D of the first valve rod 8 to press it, the second valve rod is biased by the elastic body 32. 9 moves to the cylinder chamber 4 side. The oil discharge path 11 is in communication with the cylinder chamber 4 through the second communication hole 7, and the second communication hole 7 and the oil tank chamber 5 are in a closed state, so that the pressure oil in the cylinder chamber 4 is closed. Is discharged to the oil discharge path 11 and circulates to the pressure feeding means 13. During the return movement, the elastic body 32 causes the oil drainage path 11 to communicate with the cylinder chamber 4 through the second communication hole 7, and the second communication hole 7 and the oil tank chamber 5 are closed to each other. The movable position of the second valve rod 9 through which the internal pressure oil is discharged to the oil discharge path 11 is positioned and maintained (see FIG. 4).

Therefore, the piston 3 is pushed toward the cylinder chamber 4 side by the hydraulic pressure of the pressure oil flowing into the oil tank chamber 5 and moves back.

Next, when the piston 3 reaches the backward movement end position (forward movement start position), the cylinder chamber side protrusion 8A of the first valve rod 8 contacts the top wall surface of the cylinder chamber 4 and the first valve rod 8
Moves toward the oil tank chamber 5 side, and at the same time as the first valve rod 8 moves, the engaging body 18 passes over the engaging portion 16 and disengages.
The cylinder chamber side protrusion 9A of the second valve rod 9 contacts the top wall surface of the cylinder chamber 4, the second valve rod 9 moves against the elastic body 32 toward the oil tank chamber 5 side, and returns to the state of FIG.

Therefore, in the present embodiment, the automatic switching valve structure in which the piston automatically reciprocates by pressure feeding the pressure oil to the first valve rod by the pressure feeding means without using the solenoid valve or the manual switching valve is provided. The structure is simple because it is a double-acting hydraulic cylinder.
Since only one system is required, a small and lightweight punching machine can be realized.

In this embodiment, the piston 3 is configured to move back by sending pressure oil into the oil tank chamber 5. However, the piston 3 reaches the forward end point position (return start point position). Even if the supply of the pressure oil is stopped at this point, a mechanism is provided in which the first communication hole 6 is opened by the first valve rod 8 at this time, so that the pressure oil in the cylinder chamber 4 is discharged from the first communication hole 6 to the oil tank. Room 5
The piston 3 may be automatically moved back by the returning force of the return spring 2 by flowing to the side.

Further, the present invention is not limited to this embodiment, and the specific constitution of each constituent element can be designed appropriately.

[0067]

Since the present invention is configured as described above, the piston automatically reciprocates by pressure-feeding the pressure oil to the first valve rod by the pressure-feeding means without using a solenoid valve or a manual switching valve. The structure is simple due to the automatic switching valve structure,
It is a compact and lightweight double-acting hydraulic cylinder.

Therefore, for example, if the compact and lightweight double-acting hydraulic cylinder of the present invention is adopted as the hydraulic actuator of the punching machine described in the section of the prior art, it is compact and lightweight and has excellent handleability. It is an epoch-making double-acting hydraulic cylinder that is extremely practical and can be used to configure a punching machine.

According to the second aspect of the invention, the first valve rod actuating mechanism and the second valve rod actuating mechanism capable of reliably exhibiting the above-described effects can be easily designed and realized, and the production is easier and the mass productivity is improved. It becomes an excellent double-acting hydraulic cylinder.

According to the third aspect of the invention, it is easier to manufacture the first valve rod actuating mechanism and the second valve rod actuating mechanism that surely exhibit the above-mentioned effects, and the compounding method is more excellent in mass productivity. It becomes a dynamic hydraulic cylinder.

Further, in the invention according to claim 4, the state in which the first valve rod communicates the oil tank chamber and the oil feed path is automatically maintained when the piston is returned, and the second valve rod is held in the cylinder chamber. Since the state in which the oil discharge path and the oil discharge path are in communication is automatically maintained, the double-acting hydraulic cylinder is excellent, in which stable return movement is always maintained.

[Brief description of drawings]

FIG. 1 is a perspective view showing a punching machine of the present embodiment.

FIG. 2 is an enlarged cross-sectional view of a main part of the present embodiment at the start of piston forward movement.

FIG. 3 is an enlarged cross-sectional view of an essential part showing a state in the middle of a piston forward movement according to the present embodiment.

FIG. 4 is an enlarged cross-sectional view of an essential part showing a state in which the piston of the present embodiment is at the forward movement end position (return movement start position).

[Explanation of symbols]

1 cylinder 2 Return spring 3 pistons 4 cylinder chamber 5 oil tank room 6 First conduction hole 7 Second conduction hole 8 first valve 8A Cylinder chamber side protrusion 8B Oil tank chamber side protrusion 9 Second valve rod 9A Cylinder chamber side protrusion 9B Oil tank chamber side protrusion 10 Oil supply route 11 Oil drainage route 12 Pressure oil circulation path 13 Pumping means 14 First open holding mechanism 15 Second open holding mechanism 20 First valve rod actuation mechanism 21 Second valve rod actuation mechanism 22 First sealing surface 23 Second sealing surface 24 Third sealing surface 25 Fourth sealing surface

Claims (4)

[Claims] 1. A first communicating hole for communicating between a piston that is pressed by pressure oil that is pressure-fed into a cylinder and is movable against a return spring, and a piston provided in this piston that communicates with an oil tank chamber on the opposite side of the cylinder chamber. And a second conduction hole, a first valve rod movably provided in the first conduction hole to open and close the first conduction hole by movement, and a second valve hole movably provided in the second conduction hole to move the second conduction hole. A second valve rod that opens and closes the conduction hole, an oil feed path that pressure-feeds the pressure oil to the first conduction hole, an oil discharge path that discharges the pressure oil from the second conduction hole, and this oil feed path and oil discharge. A pressure oil circulation path that connects the path to the pressure oil discharged from the oil discharge path and circulates the pressure oil by the pressure feeding means into the cylinder through the oil supply path and the first conduction hole; and the piston is on the cylinder chamber side. In the state of being located at When the piston chamber moves to the oil tank chamber side while the first communication hole and the oil tank chamber are closed, and the piston is moved to the oil tank chamber side, the oil feeding path is connected to the oil tank chamber through the first communication hole. In the state where the first valve rod actuating mechanism that controls the operation of the first valve rod so that the first communication hole and the cylinder chamber are in the closed state while being in the communication state and the piston is located on the cylinder chamber side, , The drain passage communicates with the oil tank chamber through the second communicating hole, the second communicating hole and the cylinder chamber are closed, and the piston moves to the oil tank chamber side, the drain oil is discharged. A second valve rod actuating mechanism for controlling the operation of the second valve rod so that the passage is in communication with the cylinder chamber through the second conducting hole, and the second conducting hole and the oil tank chamber are closed. A double-acting hydraulic cylinder characterized by comprising. 2. The first valve rod has a first sealing surface that closes the first communication hole when the first valve rod moves to the oil tank chamber side, and a first seal surface when the first valve rod moves to the cylinder chamber side. A second seal surface for closing the conduction hole is provided, and when the first seal surface of the first valve rod closes the first conduction hole, the oil feeding path is provided through the first conduction hole to the cylinder chamber or The first valve rod operation in which the oil feed passage is in communication with the oil tank chamber or the cylinder chamber through the first conduction hole when the second sealing surface closes the first conduction hole And a second seal when the second valve rod is moved to the oil chamber side and a third sealing surface that closes the second communication hole when the second valve rod is moved to the oil chamber side; A fourth sealing surface for closing the conduction hole is provided, and when the third sealing surface of the second valve rod closes the second conduction hole. The oil drain passage is in communication with the oil tank chamber or the cylinder chamber through the second conduction hole, and when the fourth sealing surface closes the second conduction hole, the oil drain passage is passed through the second conduction hole. 2. The double-acting hydraulic cylinder according to claim 1, wherein the second valve rod actuating mechanism is in communication with the cylinder chamber or the oil tank chamber. 3. The first valve rod and the second valve rod are respectively provided with a cylinder chamber side protrusion protruding toward the cylinder chamber side and an oil tank chamber side protrusion protruding toward the oil chamber. Is located on the cylinder chamber side, and the first valve rod is moved to the oil tank chamber side by directly or indirectly contacting the cylinder chamber side protrusion of the first valve rod with a predetermined position in the cylinder chamber, The first sealing surface of the first valve rod closes the first conduction hole, and the oil feed path is in communication with the cylinder chamber or the oil tank chamber via the first conduction hole,
When the piston moves to the oil tank chamber side and the oil tank chamber side protrusion of the first valve rod directly or indirectly abuts a predetermined position in the oil tank chamber, the first valve rod moves to the cylinder chamber side. , The first valve rod has a second sealing surface that closes the first communication hole, and the oil feed path is in communication with the oil tank chamber or the cylinder chamber through the first communication hole. The second valve rod constitutes an operating mechanism of the rod, the piston is located on the cylinder chamber side, and the protrusion on the cylinder chamber side of the second valve rod comes into direct or indirect contact with a predetermined position in the cylinder chamber so that the second valve rod is an oil tank. In the state in which the second valve rod is moved to the chamber side, the third sealing surface of the second valve rod closes the second conduction hole, and the oil discharge path communicates with the cylinder chamber or the oil tank chamber through the second conduction hole. State, the piston moves to the oil tank chamber side, and the second valve In the state where the second valve rod is moved to the cylinder chamber side by directly or indirectly contacting the oil tank chamber side protruding portion of the oil tank chamber side protruding portion with the predetermined position in the oil tank chamber, the fourth sealing surface of the second valve rod is The second valve rod actuating mechanism is configured such that the second oil passage is closed while the second oil passage is in communication with the oil tank chamber or the cylinder chamber via the second air passage. The double-acting hydraulic cylinder described in 2. 4. When the piston is returned, the first valve rod is moved toward the cylinder chamber side so that the oil feed path is in communication with the oil tank chamber via the first conduction hole. A first opening holding mechanism for positioning and holding the movable position of the first valve rod for sending pressure oil into the oil tank chamber when the communication hole and the cylinder chamber are closed is provided, and the second valve rod is provided in the cylinder chamber. To the side, the oil discharge path is in communication with the cylinder chamber through the second communication hole, the second communication hole and the oil tank chamber are closed, and the pressure oil in the cylinder chamber is discharged. The double-acting hydraulic cylinder according to any one of claims 1 to 3, further comprising a second opening holding mechanism that positions and holds the movable position of the second valve rod that is discharged to the path.