JP7008321B2 - Hydraulic actuator and puncher - Google Patents

Description

The present invention relates to a hydraulically actuated device and a puncher equipped with the hydraulically actuated device.

Conventionally, as a hydraulic actuating device used for a puncher or the like, as described in Patent Document 1, for example, when the piston is moved to one side, it is moved by hydraulic pressure, and when it is moved to the other side, it is moved by the force of a spring. There is a so-called single-acting hydraulic actuation device that moves.

Further, for example, as described in Patent Document 2, it has a first cylinder chamber and a second cylinder chamber, and a so-called double-acting piston is reciprocated by generating hydraulic pressure in the first cylinder chamber or the second cylinder chamber. It is a dynamic hydraulic actuating device.

Further, the applicant provides a hydraulic actuating device capable of reliably returning the piston to the initial position as described in Patent Document 3. The hydraulic actuating device is shown in FIG . FIG. 7 is a diagram in which 100 is added to each reference code in FIG. 1 of Patent Document 3.

As shown in FIG. 7 , the hydraulic actuating device 104 includes a cylinder 106, a piston 108 slidably arranged in the cylinder 106, and a first cylinder formed on one side of the piston 108 in the cylinder 106. It includes a chamber 114A, a second cylinder chamber 114B formed on the other side of the piston 108 in the cylinder 106, and a third cylinder chamber 120 formed between the outer periphery of the piston and the inner surface of the cylinder. The piston 108 is urged toward the first cylinder chamber 114A by the return spring 123.

Further, a first oil supply path 124 that opens to the first cylinder chamber 114A on the inner surface of the cylinder, a second oil supply path 126 that opens to the second cylinder chamber 114B on the inner surface of the cylinder, and a third cylinder chamber 120 on the inner surface of the cylinder. An oil discharge path 112 is provided.

A switching valve 140 is provided to switch the communication state between the first cylinder chamber 114A and / or the second cylinder chamber 114B and the third cylinder chamber 120.

During normal operation, when the piston 108 is moved to the second cylinder chamber 114B side, the switching valve 140 communicates the second cylinder chamber 114B and the oil discharge passage 112 (that is, the third cylinder chamber 120) with the first cylinder chamber 114A. When the communication between the cylinder chamber 112 and the oil discharge passage 112 (third cylinder chamber 120) is cut off and the piston 108 is moved to the first cylinder chamber 114A side, the first cylinder chamber 114A and the second cylinder chamber 114B and the oil discharge passage 112 ( It operates so as to communicate with the third cylinder chamber 120).

On the other hand, when the piston 108 does not return to the first cylinder chamber 114A side due to the urging force of the return spring 123 (during non-normal operation), the switching valve 140 moves the piston 108 to the first cylinder chamber 114A side. The first cylinder chamber 114A and the oil discharge passage 112 (third cylinder chamber 120) are communicated with each other, and the operation is performed so as to cut off the communication between the second cylinder chamber 114B and the oil discharge passage 112 (third cylinder chamber 120).

According to such a hydraulic actuating device 104, the urging force of the return spring 123 returns the piston 108 to the initial position during normal operation, so that even if the oil supply is stopped due to some trouble, the piston 108 is surely placed in the initial position. Can be returned to. Further, when the piston 108 does not return due to the urging force of the return spring 123, the hydraulic pressure returns the piston 108 to the initial position, so that the piston 108 can be reliably returned to the initial position even in this case.

Japanese Unexamined Patent Publication No. 8-42517 Japanese Patent No. 372160 Japanese Patent No. 6056773

The inventor of the present invention has found that the axial length of the piston can be shortened by further improving the configuration of Patent Document 3.

In the configuration of Patent Document 3, it is necessary that the third cylinder chamber 120 always communicates with the oil discharge passage 112 regardless of the sliding state of the piston 108. Therefore, the axial length of the third cylinder chamber 120 needs to correspond to the sliding movement stroke of the piston 108. Along with this, the length of the switching valve 140 and the length of the piston 108 have been required to be appropriate.

The present inventor does not use the space between the outer peripheral surface of the piston and the inner surface of the cylinder (third cylinder chamber 120) as a communication point between the first cylinder chamber 114A and / or the second cylinder chamber 114B and the oil discharge path 112. It was found that the length of the switching valve 140 and, by extension, the length of the piston 108 can be shortened by using the inside of the piston 108.

The present invention has been devised based on the above findings. An object of the present invention is to provide a hydraulic actuating device capable of reliably returning the piston to the initial position and realizing miniaturization, and a puncher provided with the hydraulic actuating device.

In the present invention, a cylinder, a piston slidably arranged in the cylinder, a first cylinder chamber formed on one side of the cylinder in the cylinder, and the other of the piston in the cylinder. A second cylinder chamber formed on the side, a first oil supply path that opens into the first cylinder chamber on the inner surface of the cylinder, and a second oil supply path that opens into the second cylinder chamber on the inner surface of the cylinder. An oil discharge chamber formed inside the piston and capable of communicating with the first cylinder chamber and the second cylinder chamber, and a state of communication between the first cylinder chamber and / or the second cylinder chamber and the oil discharge chamber. The switching valve is provided with a switching valve for urging the piston toward the first cylinder chamber side, and the switching valve is used when the piston is moved to the second cylinder chamber side during normal operation. When the second cylinder chamber and the oil discharge chamber are communicated with each other to cut off the communication between the first cylinder chamber and the oil discharge chamber and the piston is moved to the first cylinder chamber side, the first cylinder is used. When the chamber and the second cylinder chamber are operated so as to communicate with each other and the piston does not return to the first cylinder chamber side due to the urging force of the return spring, the switching valve causes the piston. It is characterized in that the first cylinder chamber and the oil discharge chamber are communicated with each other so as to be moved to the first cylinder chamber side, and the communication between the second cylinder chamber and the oil discharge chamber is cut off. It is a hydraulic actuation device.

According to the present invention, when the piston moves to the second cylinder chamber side during normal operation, the switching valve communicates the second cylinder chamber and the oil discharge chamber with the first cylinder chamber and the oil discharge chamber. Block communication. As a result, the oil supplied from the first oil supply passage is stored in the first cylinder chamber to generate hydraulic pressure, while the oil supplied from the second oil supply passage stores in the second cylinder chamber. It is discharged from the oil discharge chamber through. Therefore, the piston moves to the second cylinder chamber side by the hydraulic pressure generated in the first cylinder chamber.

Further, during normal operation, when the piston moves to the first cylinder side, the switching valve communicates the first cylinder chamber and the second cylinder chamber with the oil discharge chamber. As a result, the oil supplied from the first oil supply passage and the second oil supply passage is discharged to the oil discharge chamber via the first cylinder chamber and the second cylinder chamber, respectively, and the first cylinder chamber and the second cylinder chamber are discharged. No oil pressure is generated in the cylinder chamber. Then, the piston moves to the first cylinder chamber side by the urging force of the return spring.

On the other hand, when the piston does not return to the first cylinder chamber side due to the urging force of the return spring due to some trouble or the like, the switching valve communicates the first cylinder chamber and the oil discharge chamber and supplies the oil to the second cylinder chamber. Block communication with the room. As a result, the oil supplied from the first oil supply passage is discharged from the oil discharge chamber via the first cylinder chamber, while the oil supplied from the second oil supply passage is discharged from the second cylinder chamber. It stores in and generates oil pressure. Therefore, the piston moves to the first cylinder chamber side due to the hydraulic pressure generated in the second cylinder chamber.

As described above, according to the hydraulic actuating device according to the present invention, the urging force of the return spring returns the piston to the initial position during normal operation, so that even if the oil supply is stopped due to some trouble, the piston can be reliably operated. It can be returned to the initial position. Further, when the piston does not return due to the urging force of the return spring, the hydraulic pressure returns the piston to the initial position, so that the piston can be reliably returned to the initial position even in this case.

According to the present invention, the oil discharge chamber that can communicate with the first cylinder chamber and the second cylinder chamber is formed inside the piston, not between the outer periphery of the piston and the inner surface of the cylinder. The size of the discharge chamber can be designed independently of the sliding stroke of the piston, and the length of the switching valve, and thus the length of the piston, can be shortened.

The oil discharge chamber preferably has a tubular chamber extending in the axial direction of the piston and a radial chamber extending radially outward from the tubular chamber.

In this case, the length of the switching valve, and thus the length of the piston, can be further shortened by communicating with the first cylinder chamber and the second cylinder chamber by the radial chamber, while the piston by the tubular chamber. Can be responsible for the design to absorb the sliding stroke of.

For example, one end side of a hollow shaft connected to an oil discharge path in the cylinder is fixed to the cylinder, and the other end side of the hollow shaft extends inside the tubular chamber of the oil discharge chamber. The piston is adapted to slide and move with respect to the hollow shaft, and during the sliding movement of the piston with respect to the hollow shaft, the inside of the other end side of the hollow shaft and the oil discharge chamber. The state of communication with the inside of the tubular chamber is maintained.

According to such a configuration, when the piston slides and moves with respect to the cylinder (that is, the hollow shaft), the tubular chamber can absorb the sliding stroke of the piston.

Further, the piston is formed with a communication hole that communicates the first cylinder chamber and the second cylinder chamber and also communicates with the oil discharge chamber, and the switching valve is a slide rod that penetrates the communication hole. A first valve provided at one end of the slide rod to close the opening of the communication hole on the first cylinder chamber side and an opening of the communication hole on the second cylinder chamber side provided at the other end of the slide rod. It is preferable to have a second valve that closes the valve.

In this case, since the first valve is provided at one end of the slide rod and the second valve is provided at the other end of the slide rod, the slide rod is used so that the first valve closes the opening on the first cylinder chamber side. When moved, the communication between the first cylinder chamber and the communication hole is cut off, and the second cylinder chamber and the oil discharge chamber communicate with each other through the communication hole. On the other hand, when the slide rod moves so that the second valve closes the opening on the second cylinder chamber side, the communication between the second cylinder chamber and the communication hole is cut off, and the communication hole between the first cylinder chamber and the oil discharge chamber is cut off. Communicate through. Further, when the slide rod is moved to a position where both the opening on the first cylinder chamber side and the opening on the second cylinder chamber side are opened, both the first cylinder chamber and the second cylinder chamber are oiled through the communication holes. Communicate to the discharge chamber.

Therefore, in this case, with a simple structure by moving the slide rod, only the first cylinder chamber is shut off, only the second cylinder chamber is shut off, and both the first cylinder chamber and the second cylinder chamber are opened. It can be done selectively.

Further, the switching valve is provided with a holding spring that urges the switching valve to the first cylinder chamber side, and the urging force of the holding spring is the urging force of the piston by the urging force of the return spring. When both the first valve and the second valve of the switching valve are opened while moving to the one cylinder chamber side, and the piston does not move to the first cylinder chamber side due to the urging force of the return spring. , It is preferable that the second valve is set to close.

In this case, the holding spring urges the switching valve to the first cylinder chamber side, and during normal operation, when the piston is moved to the first cylinder chamber side by the urging force of the return spring, the switching valve is urged. , Stable in the position where both the first valve and the second valve are opened. Further, when the piston does not move to the first cylinder chamber side due to the urging force of the return spring, the switching valve stabilizes at the position where the second valve closes due to the urging force of the holding spring.

Therefore, in this case, by setting the urging force of the holding spring, both the first valve and the second valve can be opened or the second valve can be closed, that is, the switching valve has a simple structure. The desired switching operation can be realized.

Further, in the second cylinder chamber, when the piston moves to the end on the side of the second cylinder chamber, a stopper that comes into contact with the switching valve and the switching valve are pressed to the side of the first cylinder chamber. It is preferable that a kick spring for moving the cylinder is provided.

In this case, when the piston moves to the end on the second cylinder chamber side, the switching valve comes into contact with the stopper, and the switching valve is pressed by the kick spring to move to the first cylinder side. At this time, during normal operation, the switching valve opens both the first valve and the second valve, and if the piston does not return due to the urging force of the return spring, the switching valve opens the first valve and the first valve. 2 Close the valve.

Therefore, in this case, the stopper and the kick spring can easily trigger the operation of the switching valve, that is, the desired switching operation of the switching valve can be realized with a simple structure.

Further, the puncher according to the second aspect of the present invention is characterized by being provided with the above-mentioned hydraulic actuating device. Since the puncher according to the second aspect of the present invention is provided with the above-mentioned hydraulic actuating device, the same effect as described above can be obtained.

According to the present invention, the oil discharge chamber that can communicate with the first cylinder chamber and the second cylinder chamber is formed inside the piston, not between the outer periphery of the piston and the inner surface of the cylinder. The size of the piston can be designed independently of the sliding stroke of the piston, and the length of the switching valve, and thus the length of the piston, can be shortened.

It is sectional drawing of the puncher which concerns on one Embodiment of this invention. It is a partially enlarged sectional view of the puncher which concerns on one Embodiment of this invention. It is a figure which shows the operation of the puncher which concerns on one Embodiment of this invention. It is a figure which shows the operation of the puncher which concerns on one Embodiment of this invention. It is a figure which shows the operation of the puncher which concerns on one Embodiment of this invention. It is a figure which shows the operation of the puncher which concerns on one Embodiment of this invention. It is sectional drawing of the puncher by patent document 3. FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view of a puncher 1 according to an embodiment of the present invention. In the present embodiment, the vertical direction in FIG. 1 is described as the vertical direction of the puncher 1, but the puncher 1 can be arranged in any direction.

As shown in FIG. 1, the puncher 1 includes a punch 2 and a hydraulic actuating device 4 for reciprocating the punch 2.

The hydraulic actuating device 4 is for supplying hydraulic oil to the cylinder body 6, the head 7 fixed to the cylinder body 6, the piston 8 slidably provided in the cylinder body 6, and the cylinder body 6. It includes oil supply passages 24 and 26, and an oil discharge passage 12 for discharging hydraulic oil from the inside of the cylinder body 6.

The cylinder body 6 forms two cylinder chambers 14a and 14b inside, and the lower ends of the cylinder chambers 14a and 14b are closed by the head 7. The cylinder chambers 14a and 14b are divided into a first cylinder chamber 14a and a second cylinder chamber 14b by a piston 8.

The piston 8 has a piston head 8h that divides the cylinder chambers 14a and 14b, and a piston rod 8r that protrudes from the piston head 8h toward the second cylinder chamber 14b. Two O-rings 22 (and grooves for the O-rings) are provided on the outer periphery of the piston head 8h, and the first cylinder chamber 14a and the second cylinder chamber 14b are separated by these O-rings 22. ..

The piston rod 8r penetrates the cylinder body 6 and extends to the outside, and is connected to the punch 2 at the end. A return spring 23 for urging the piston 8 to the upper side (first cylinder chamber 14a side) is provided between the lower surface of the piston head 8h and the lower surface of the second cylinder chamber 14b. The return spring 23 is a double compression spring, one end of which is fixed to the lower surface of the piston head 8h and the other end of which is fixed to the lower surface of the cylinder chamber 14b.

The oil supply paths 24 and 26 of the present embodiment are a first oil supply path 24 for supplying hydraulic oil to the first cylinder chamber 14a and a second oil supply path 26 for supplying hydraulic oil to the second cylinder chamber 14b. And have.

Two first oil supply passages 24 are formed in the cylinder body 6 and are provided above the first cylinder chamber 14a with an angle interval of 90 degrees from each other. Above Only one of the two first oil supply channels 24 is shown. As shown in FIG. 1, the first oil supply path 24 extends in a direction parallel to the axial direction of the cylinder chambers 14a and 14b.

One end of the first oil supply path 24 is open to the upper surface of the first cylinder chamber 14a. As a result, the first oil supply path 24 communicates with the first cylinder chamber 14a. The other end of the first oil supply channel 24 is connected to a plunger 28 (one of the two plungers is shown in FIG. 1). The plunger 28 is connected to a pump (not shown).

The second oil supply path 26 is formed in the cylinder body 6, passes above and outside the two cylinder chambers 14a and 14b, and reaches the vicinity of the lower end of the second cylinder chamber 14b in the axial direction of the cylinder chambers 14a and 14b. It extends in a direction parallel to.

One end of the second oil supply path 26 is open to the side surface of the second cylinder chamber 14b. As a result, the second oil supply path 26 communicates with the second cylinder chamber 14b. More specifically, the lower end of the second cylinder chamber 14b is provided with a conical trapezoidal region 14c extending downward, and one end of the second oil supply path 26 is the conical trapezoidal region 15. It opens at a right angle to the inclined side surface. The other end of the second oil supply path 26 is arranged at an angular distance of 90 degrees from one of the first oil supply paths 24 and is connected to the plunger 30. The plunger 30 is connected to a pump (not shown).

As described above, two first oil supply passages 24 are connected to the first cylinder chamber 14a, and one second oil supply passage 26 is connected to the second cylinder chamber 14b.

The oil discharge passage 12 is formed in the cylinder body 6, the upper end portion of the hollow shaft 71 described later is fixed to the lower side of the oil discharge passage 12, and the upper side of the oil discharge passage 12 is a hydraulic oil storage (not shown). It is connected to the room. Further, the flow path from the oil discharge passage 12 to the hydraulic oil storage chamber is communicated with the hydraulic oil amount adjusting chamber 32 adjacent to the air pack 38. With such an arrangement configuration, the air pack 38 can function as a balancer for adjusting the amount of hydraulic oil.

The hollow shaft 71 penetrates the sliding through hole 8s provided along the central axis of the piston head 8h and extends to the inside of the tubular chamber 20c provided inside the piston head 8h. An O-ring 72 (and a groove for the O-ring) is provided on the inner circumference of the sliding through hole 8s of the piston head 8h, and the O-ring 72 separates the first cylinder chamber 14a from the tubular chamber 20c. Has been done.

The radial chamber 20r extends from the tubular chamber 20r toward the predetermined radial outer side. The tubular chamber 20c and the radial chamber 20r form an oil discharge chamber 20.

The sliding through hole 8s of the piston 8 slides with respect to the hollow shaft 71, and during the sliding movement, the inside of the lower end side of the hollow shaft 71 and the inside of the cylindrical chamber 20c. The communication state of is maintained. As a result, the communication state between the oil discharge path 12 and the inside of the tubular chamber 20c is maintained during the sliding movement.

The piston head 8h is provided with a switching valve 40 for switching the communication state between the first cylinder chamber 14a and / or the second cylinder chamber 14b and the oil discharge chamber 20.

FIG. 2 is a partially enlarged cross-sectional view of the puncher 1 of FIG. As shown in FIG. 2, the switching valve 40 is provided in the communication hole 42 formed in the piston head 8h. The communication hole 42 is a vertical hole formed along the axial direction of the piston 8 so as to penetrate the upper and lower surfaces of the piston head 8h. A first large diameter portion 44a and a second large diameter portion 44b having a diameter larger than that of the central portion are formed in the upper portion and the lower portion of the communication hole 42. The lower end of the first large diameter portion 44a and the upper end of the second large diameter portion 44b communicate with the radial chamber 20r of the oil discharge chamber 20.

Here, the length of the radial chamber 20r along the axial direction of the piston 8, that is, the distance between the lower end portion of the first large diameter portion 44a and the upper end portion of the second large diameter portion 44b is the distance of the piston 8. It can be designed independently of the movement stroke. As a result, the length of the radial chamber 20r along the axial direction of the piston 8, that is, the distance between the lower end portion of the first large diameter portion 44a and the upper end portion of the second large diameter portion 44b is compactly shortened. It can be designed, and as a result, the piston head 8h can be downsized.

The switching valve 40 of the present embodiment is a slide rod 48 slidably arranged in the communication hole 42, and a first valve provided at the upper end of the slide rod 48 and capable of closing the opening above the communication hole 42. It has a 50 and a second valve 52 provided at the lower end of the slide rod 48 and capable of closing the opening below the communication hole 42.

More specifically, the slide rod 48 is formed with a diameter slightly smaller than the diameter of the central portion of the communication hole 42, and is formed longer than the longitudinal dimension of the communication hole 42. Therefore, when the slide rod 48 is inserted into the communication hole 42, its end portion protrudes from the communication hole 42.

Then, the first valve 50 is formed in a disk shape having a diameter larger than the diameter of the first large diameter portion 44a, for example, and the lower surface of the first valve 50 can close the first large diameter portion 44a. There is. The upper surface of the first valve 50 of the present embodiment is slightly formed in a conical shape or an arc-shaped cross section.

Similarly, the second valve 52 is also formed in a disk shape having a diameter larger than the diameter of the second large diameter portion 44b, for example, so that the upper surface of the second valve 52 can close the second large diameter portion 44b. ing. A protruding portion 52a projecting downward is formed on the lower surface of the second valve 52 of the present embodiment.

Further, inside the first large diameter portion 44a, a holding spring 54 for urging the switching valve 40 upward to hold the first valve 50 of the switching valve 40 in the opening direction is provided. As shown, the upper end of the holding spring 54 is in contact with the lower surface of the first valve 50 of the switching valve 40, and the lower end of the holding spring 54 is in contact with the lower surface of the first large diameter portion 44a. ing.

Further, at the lower end of the second cylinder chamber 14b, at a position corresponding to directly below the switching valve 40, a cylindrical stopper 55 fixed in a recess 53 formed in the head 7 is provided. Then, one end of a kick spring 56 for pushing up the switching valve 40 upward when the piston 8 reaches the bottom dead center is fixed to the stopper 55. The other end of the kick spring 56 protrudes above the upper end of the stopper 55 when no load is applied. The kick spring 56 has a diameter larger than the diameter of the protrusion 52a of the second valve 52 and smaller than the diameter of the second valve 52 itself.

Next, the operation of this embodiment will be described.

(During normal operation)
First, as shown in FIG. 2, in the puncher 1 in the initial state, the piston 8 is moved to the top dead center at the upper end of the first cylinder chamber 14a by the urging force of the return spring 23. In this initial state, the upper end of the first valve 50 of the switching valve 40 is in contact with the upper surface of the first cylinder chamber 14a.

In this state, when the pumping of the hydraulic oil is started, the hydraulic oil enters the first cylinder chamber 14a through the two first oil supply passages 24 via the plunger 28. Further, the hydraulic oil enters the second cylinder chamber 14b through one second oil supply passage 26 via the plunger 30.

When the piston 8 is at top dead center, the first valve 50 is closed, that is, the first cylinder chamber 14a and the first large diameter portion 44a are shut off. Therefore, the hydraulic oil that has entered the first cylinder chamber 14a is stored in the first cylinder chamber 14a to generate pressure. Then, the hydraulic oil enters between the upper surface of the first valve 50 and the upper surface of the first cylinder chamber 14a, and generates hydraulic pressure on the upper surface of the first valve 50. This hydraulic pressure keeps the first valve 50 pressed downward against the urging force of the holding spring 54, i.e., the first valve 50 remains closed.

On the other hand, when the piston 8 is at top dead center, the upper surface of the second valve 52 does not block the second large diameter portion 44b. Therefore, the hydraulic oil that has entered the second cylinder chamber 14b from the second oil supply passage 26 enters the radial chamber 20r of the oil discharge chamber 20 through the second large diameter portion 44b, and then enters the tubular chamber 20c and the tubular chamber 20c. It is discharged to the oil discharge path 12 through the inside of the hollow shaft 71. Therefore, no hydraulic pressure is generated in the second cylinder chamber 14b.

Due to the hydraulic pressure generated in the first cylinder chamber 14a due to the behavior of the hydraulic oil as described above, the piston 8 moves downward as shown in FIG.

FIG. 4 shows a state in which the piston 8 has moved to the bottom dead center. When the piston 8 reaches the bottom dead center, the punch 2 coupled to the lower end of the piston rod 8r drills the material. At this time, the upper end of the kick spring 56 comes into contact with the lower surface of the second valve 52, and the protruding portion 52a of the second valve 52 of the switching valve 40 comes into contact with the stopper 55.

After that, due to the repulsive force by the stopper 55 and / or the urging force of the kick spring 56, the second valve 52 moves upward against the hydraulic pressure in the first cylinder chamber 14a, and the first valve 50 opens.

When the first valve 50 is opened, the hydraulic oil in the first cylinder chamber 14a passes through the first large diameter portion 44a and enters the radial chamber 20r of the oil discharge chamber 20, and then the tubular chamber 20c and the hollow shaft 71. It is discharged to the oil discharge passage 12 through the inside of the oil. Therefore, the hydraulic pressure in the first cylinder chamber 14a is released. As a result, the urging force of the return spring 23 causes the piston 8 to start moving upward.

At this time, the switching valve 40 is held in a state where both the first valve 50 and the second valve 52 are open. This is because the hydraulic oil in the first cylinder chamber 14a is discharged when the piston 8 moves upward, so that a downward force is applied to the first valve 50, and this force and the holding force of the holding spring 54 are applied. This is because it is balanced with. This state is shown in FIG.

In other words, the urging force of the holding spring 54 of the present embodiment is subject to conditions such as the urging force of the return spring 23, the characteristics of the hydraulic oil flowing through the first cylinder chamber 14a and the second cylinder chamber 14b, and the moving speed of the piston 8. Based on this, as shown in FIG. 5, both the first valve 50 and the second valve 52 are set to be held in the open position.

When the upward movement of the piston 8 is continued and the top dead center is reached, the upper surface of the first valve 50 of the switching valve 40 comes into contact with the upper surface of the first cylinder chamber 14a. As a result, the first valve 50 closes and returns to the initial state shown in FIG.

(During non-normal operation)
Next, the operation when the piston 8 does not return to the initial state due to the urging force of the return spring 23 due to some trouble such as the punch 2 getting caught in the material when the material is drilled will be described.

When the piston 8 does not move upward due to the urging force of the return spring 23, the moving speed of the piston 8 becomes 0. At this time, the equilibrium between the urging force of the holding spring 54 and other conditions is lost, the urging force of the holding spring 54 prevails, and the holding spring 54 pushes up the switching valve 40 to the upper end. This state is shown in FIG.

As a result, the second valve 52 is closed and hydraulic pressure is generated in the second cylinder chamber 14b. On the other hand, since the first valve 50 is open, the hydraulic oil that has entered the first cylinder chamber 14a enters the radial chamber 20r of the oil discharge chamber 20 through the first large diameter portion 44a, and then enters the tubular chamber. It is discharged to the oil discharge path 12 through the inside of the 20c and the hollow shaft 71. Therefore, no hydraulic pressure is generated in the first cylinder chamber 14a. Therefore, the piston 8 starts moving upward by the hydraulic pressure generated in the second cylinder chamber 14b.

When the upward movement of the piston 8 is continued and the top dead center is reached, the upper surface of the first valve 50 of the switching valve 40 comes into contact with the upper surface of the first cylinder chamber 14a. As a result, the first valve 50 closes and returns to the initial state shown in FIG.

According to the present embodiment as described above, the following effects can be obtained.

During the normal operation of the puncher 1, when the piston 8 moves upward, the switching valve 40 opens both the first valve 50 and the second valve 52, while the piston 8 moves upward due to the urging force of the return spring 23. When the switching valve 40 does not move to, the switching valve 40 opens the first valve 50 and closes the second valve 52, so that the piston 8 can be returned by the hydraulic force. In short, it can function as a so-called single-acting hydraulic device that returns the piston 8 by the force of the return spring 23 during normal operation, and hydraulically returns the piston 8 upward only when necessary, so-called double-acting type. Can function as a hydraulic device. As a result, while adopting a simple structure with the return spring 23, if any trouble occurs, the piston 8 can be reliably returned to the initial position by hydraulic pressure.

Further, according to the present embodiment, hydraulic oil is always supplied from the first oil supply passage 24 and the second oil supply passage 26 to the first cylinder chamber 14a and the second cylinder chamber 14b, respectively, and the switching valve 40 is switched. Since it is configured to selectively switch the communication with the oil discharge chamber 20, a desired hydraulic pressure switching operation can be realized with a simple structure using one switching valve 40.

Further, according to the present embodiment, the switching valve 40 includes a slide rod 48, a first valve 50 at one end thereof, and a second valve 52 at the other end, so that the switching valve 40 is configured. By simply moving the valve 50 to a predetermined position, it is possible to create a valve opening situation in which only the first valve 50 is closed, only the second valve 52 is closed, or both the first valve 50 and the second valve 52 are opened. Therefore, a desired hydraulic pressure switching operation can be realized with a simple structure.

Further, the holding spring 54 of the present embodiment has an urging force that opens both the first valve 50 and the second valve 52 when the piston 8 normally returns to the initial position by the return spring 23. If the piston 8 does not return to the initial position by the return spring 23 due to some trouble, the urging force is set so as to close the second valve 52. As a result, the switching operation by the switching valve 40 is performed by the balance between the urging force of the holding spring 54, the urging force of the return spring 23, the moving speed of the piston 8, and the like, and even if a problem occurs, the switching valve 40 is automatically performed. Switching operation is performed. Therefore, for example, it is not necessary to detect whether or not the vehicle is operating normally, and a simple structure can be used both during normal operation and when a problem occurs.

Further, according to the present embodiment, since the stopper 55 and the kick spring 56 are provided below the switching valve 40, the switching operation of the switching valve 40 is automatically performed when the piston 8 reaches the bottom dead center. .. Therefore, the switching timing of the switching valve 40 can be managed with a simple structure.

Further, according to the present embodiment, since the first oil supply path 24 is provided with two and the second oil supply path 26 is provided with one, the piston 8 is moved downward to make a hole or the like. When performing the work, hydraulic oil can be supplied from the two first oil supply passages 24 to quickly and reliably perform the work. On the other hand, when the piston 8 is returned upward due to some trouble, the piston 8 is moved by using one second oil supply path 26 because neither more force nor speed than necessary is required. As a result, the puncher 1 can be efficiently operated by supplying the minimum required hydraulic oil.

Then, as described above, in the present embodiment, the length of the radial chamber 20r along the axial direction of the piston 8, that is, the lower end portion of the first large diameter portion 44a and the upper end portion of the second large diameter portion 44b. The distance between them can be designed independently of the movement stroke of the piston 8. This makes it possible to reduce the size of the piston head 8h.

The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the invention described in the claims, and these are also included in the scope of the present invention. Needless to say.

For example, in the above-described embodiment, the switching of the switching valve 40 is automatically performed by setting the urging force of the holding spring 54, but the structure is not limited to this, and the structure becomes more complicated, for example, the position of the piston. Even if it is configured to switch when it detects that the piston has reached top dead center or bottom dead center, or when it detects that the piston does not return to the initial position due to the urging force of the return spring. good.

Further, the switching valve is not limited to a structure having a slide rod, a first valve, and a second valve integrally, and for example, a switching valve having a first valve and a second valve separately and controlling opening and closing of each as necessary. It may be.

Further, two first oil supply passages are connected to the first cylinder chamber, and one second oil supply passage is connected to the second cylinder chamber, but the present invention is not limited to this, and the first and second oil supply passages are connected. The number of oil supply channels installed is arbitrary. In addition, the number of oil discharge channels installed is arbitrary.

1 Puncher 2 Punch 4 Hydraulic actuator 6 Cylinder body (part of cylinder)
7 Head (part of cylinder)
8 Piston 8h Piston head (part of piston)
8r piston rod (part of piston)
8s Sliding through hole 12 Oil discharge passage 14a First cylinder chamber 14b Second cylinder chamber 14c Conical trapezoidal region 20 Oil discharge chamber 20c Cylindrical chamber 20r Radial chamber 22 O-ring 23 Return spring 24 First oil supply passage 26 2 oil supply path 28 Plunger 30 Plunger 32 Hydraulic oil amount adjustment chamber 38 Air pack 40 Switching valve 42 Communication hole 44a 1st large diameter part 44b 2nd large diameter part 48 Slide rod 50 1st valve 52 2nd valve 52a Protruding part 53 Recess 54 Retaining spring 55 Stopper 56 Kick spring 71 Hollow shaft 72 O-ring

Claims (4)

Cylinder and
A piston slidably arranged in the cylinder and
A first cylinder chamber formed on one side of the piston in the cylinder,
A second cylinder chamber formed in the cylinder on the other side of the piston,
A first oil supply path that opens into the first cylinder chamber on the inner surface of the cylinder,
A second oil supply path that opens into the second cylinder chamber on the inner surface of the cylinder,
An oil discharge chamber formed inside the piston and capable of communicating with the first cylinder chamber and the second cylinder chamber.
A switching valve for switching the communication state between the first cylinder chamber and / or the second cylinder chamber and the oil discharge chamber.
A return spring that urges the piston toward the first cylinder chamber,
Equipped with
When the piston is moved to the second cylinder chamber side during normal operation, the switching valve communicates the second cylinder chamber with the oil discharge chamber and communicates between the first cylinder chamber and the oil discharge chamber. When the piston is moved to the first cylinder chamber side, it operates so as to communicate the first cylinder chamber, the second cylinder chamber, and the oil discharge chamber.
When the piston does not return to the first cylinder chamber side due to the urging force of the return spring, the switching valve causes the first cylinder chamber and the oil discharge so as to move the piston to the first cylinder chamber side. It operates so as to communicate with the chamber and cut off the communication between the second cylinder chamber and the oil discharge chamber.
The oil discharge chamber has a tubular chamber extending in the axial direction of the piston and a radial chamber extending radially outward from the tubular chamber.
One end side of a hollow shaft connected to an oil discharge path in the cylinder is fixed to the cylinder.
The other end side of the hollow shaft extends inside the cylindrical chamber of the oil discharge chamber.
The piston is adapted to slide and move with respect to the hollow shaft.
During the sliding movement of the piston with respect to the hollow shaft, the communication state between the inside of the other end side of the hollow shaft and the inside of the cylindrical chamber of the oil discharge chamber is maintained. A puncher characterized by being equipped with a hydraulic actuation device. The piston is formed with a communication hole that communicates the first cylinder chamber and the second cylinder chamber and also communicates with the oil discharge chamber.
The switching valve is
A slide rod that penetrates the communication hole and
A first valve provided at one end of the slide rod and closing the opening of the communication hole on the first cylinder chamber side,
A second valve provided at the other end of the slide rod and closing the opening of the communication hole on the second cylinder chamber side,
The puncher according to claim 1, wherein the puncher is characterized by having. The switching valve is provided with a holding spring that urges the switching valve toward the first cylinder chamber side.
The urging force of the holding spring opens both the first valve and the second valve of the switching valve when the piston is moved to the first cylinder chamber side by the urging force of the return spring. The puncher according to claim 2, wherein the piston is set to close the second valve when the piston does not move toward the first cylinder chamber side due to the urging force of the return spring. In the second cylinder chamber, when the piston moves to the end on the side of the second cylinder chamber, the stopper that comes into contact with the switching valve and the switching valve are pressed to move to the first cylinder chamber side. The puncher according to claim 2 or 3, wherein a kick spring for causing the piston is provided.

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