JPH1096403A - Hydraulic booster device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To quickly discharge hydraulic oil from a single-acting hydraulic actuator and quickly release the same. SOLUTION: A booster mechanism 10 having a double-acting piston 11 and a booster piston 15 which are reciprocated by receiving and discharging hydraulic pressure, a hydraulic pump P and a booster mechanism 10
Oil passages 41a-41 connecting left and right cylinder chambers 12 and 13
c, an oil passage 44 connecting the booster cylinder chamber 14 and the working cylinder chamber 81 of the clamp tool 80, an oil passage 45 connecting the booster cylinder chamber 14 to the drain side, and an open / close control check valve for controlling the opening / closing of these oil passages. And an operation switching valve 1 for performing switching control between an operation mode and a release mode. In the operating mode, the operating oil discharged from the booster cylinder chamber 14 is supplied to the operating cylinder chamber 81. On the other hand, in the release mode, the operating oil in the operating cylinder chamber 81 is sucked into the booster cylinder chamber 14 to drain. Let it drain to the side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reciprocating hydraulic booster for supplying hydraulic oil to a single-acting hydraulic actuator to operate the single-acting hydraulic actuator.

[0002]

2. Description of the Related Art FIG. 4 shows a conventional hydraulic booster device. This hydraulic booster device includes a hydraulic pump P for supplying hydraulic oil, an operation switching valve 100 for controlling the operation of the device, and a booster mechanism 11.
0, and controls the operation of the clamp tool 80 by controlling the supply and discharge of ultrahigh-pressure hydraulic oil to and from the clamp tool 80 having a single-acting actuator mechanism.

When the clamp tool 80 is used, the left solenoid 101 of the operation switching valve 100 is excited to move it to the right, and the hydraulic oil from the hydraulic pump P is supplied to the left cylinder chamber 112 of the booster mechanism 110. As a result, the double-acting piston 111 moves rightward together with the booster piston 111a located at the right end thereof, and the booster cylinder chamber 1
From 14, an ultra-high pressure hydraulic oil is supplied to the working cylinder chamber 81 of the clamp tool 80. As a result, the working piston 82 is moved to the right, and the movable clamp 84 moves in a direction approaching the fixed clamp 85, and starts clamping the object.

When the double-acting piston 111 moves to the right stroke end, the double-acting control valve 120 connected thereto is switched, and the hydraulic oil from the hydraulic pump P is supplied to the right cylinder chamber 1.
13 as well. Here, the pressure receiving area of the right cylinder chamber 113 is larger than the pressure receiving area of the left cylinder chamber 112, and the difference causes the double-acting piston 111 to move leftward. At this time, the booster piston 111a is also moved to the left, and the operating oil is supplied to the booster cylinder chamber 114 while the ultra-high pressure is confined in the operating cylinder chamber 81 by the action of the check valves 115 and 116.

When the double-acting piston 111 moves to the end of the left stroke, the double-acting control valve 120 is switched, and while the hydraulic oil is supplied to the left cylinder chamber 112, the right cylinder chamber 113 is drained through the double-acting control valve 120. Connect. Therefore, the double-acting piston 111 is moved rightward. Hereinafter, the double-acting piston 111 is continuously reciprocated in this manner, and the clamping operation is performed by the clamping tool 80.

In such a clamping operation, when the hydraulic pressure in the working cylinder chamber 81 reaches a predetermined high pressure and the clamping force reaches a predetermined value, the relief valve 125 is opened,
Upon receiving this predetermined high pressure, the pressure switch 127 is operated, and the right solenoid 102 of the operation switching valve 100 is excited. As a result, the operation switching valve 100 is moved to the left, and the operating oil from the hydraulic pump P is supplied to the pilot check valve 11.
6 to open it, and the working oil in the working cylinder chamber 81 is discharged to the drain through the check valve 116. Therefore, the moving clamp 84 is provided with the return spring 83.
Is moved left by the force of, and returned to the original position.

[0007]

However, it is only the force of the return spring 83 that releases the hydraulic oil from the working cylinder chamber 81 through the check valve 116, and it takes time to release the hydraulic oil. However, there is a problem that it takes time to return to the original position. This time is particularly long when the operating oil temperature is low. For this reason, after performing work using the clamp tool, it is necessary to wait until the movable clamp 84 returns to the next work in order to perform the next work, and there is a problem that work efficiency is not good.

The present invention has been made in view of such a problem.
A reciprocating hydraulic booster device configured to supply hydraulic oil to a single-acting hydraulic actuator to operate the single-acting hydraulic actuator, and then to discharge the hydraulic oil and quickly return the actuator. The purpose is to provide.

[0009]

In order to achieve the above object, a hydraulic booster device according to the present invention is provided with a double-acting cylinder reciprocally operated by receiving a supply of operating hydraulic pressure and a reciprocating cylinder connected to the double-acting cylinder. A booster means having a booster cylinder to be driven, a first oil path connecting the hydraulic oil supply source to the booster cylinder, a second oil path connecting the booster cylinder to the single-acting hydraulic actuator, and a hydraulic booster. A third oil passage connecting the cylinder to the drain side, an opening / closing control valve group arranged in the first to third oil passages for controlling the opening / closing of these oil passages, and controlling the operation of the opening / closing control valve group; It is composed of an operation switching valve for performing switching control between an operation mode for operating the single-acting hydraulic actuator and a release mode for releasing the operation mode. When the operation switching valve is in the operation mode, the opening / closing control of the opening / closing control valve group is performed so that the operating oil discharged from the booster cylinder is supplied to the single-acting hydraulic actuator. On the other hand, when the operation switching valve is in the release mode, the opening / closing control of the opening / closing control valve group is performed so that the hydraulic oil is sucked from the single-acting hydraulic actuator by the booster cylinder and discharged to the drain side.

In the case of the hydraulic booster device, the double-acting cylinder is reciprocated to supply and discharge hydraulic oil by the booster cylinder regardless of whether the operation switching valve is in the operation mode or the release mode. The discharge oil is supplied to the single-acting hydraulic actuator by using the discharge operation of the booster cylinder, and is actuated. On the other hand, in the release mode, the discharge oil is supplied to the single-acting hydraulic actuator by using the return operation (suction operation) of the booster cylinder. The discharged hydraulic oil is sucked and discharged. Therefore, even when the operating oil temperature is low, the release operation of the single-acting hydraulic actuator can be quickly performed in a short time.

When the operation switching valve is in the release mode, the hydraulic oil is sucked from the single-acting hydraulic actuator through the second oil passage by the booster cylinder and the drain is drained while the third oil passage is always opened to the drain side. The opening and closing control of the opening and closing control valve group may be configured to be discharged to the side.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. First, FIG. 1 shows a first embodiment, and shows a hydraulic booster device for supplying and discharging ultrahigh-pressure hydraulic oil to and from the same clamping tool 80 as shown in FIG. This hydraulic booster device includes a hydraulic pump P for supplying hydraulic oil, an operation switching valve 1 for controlling the operation of the hydraulic booster device (switching between an operation mode and a release mode), a shuttle valve 20, and a booster mechanism 1.
0 is a basic configuration, and a relief valve 25, a pressure switch 27, a plurality of check valves 31 to 34, and the like are arranged and arranged as shown in FIG.

The operation switching valve 1 includes left and right solenoids 2,
3 are selectively energized and activated. Shuttle valve 2
0, the shuttle ball 21 moves according to the oil pressure of the left and right oil passages 41a and 41b, and the high pressure side oil passage is moved to the oil passage 41.
and closes the low pressure side oil passage. Booster mechanism 1
Numeral 0 denotes a double-acting piston 11 that is reciprocated by receiving a supply of hydraulic oil to the left and right cylinder chambers 12 and 13, a booster piston 15 integrally connected to the double-acting piston, and a double-acting piston 11 Double-acting control valve 1 linked to this
And 7. Note that the booster piston 15 is reciprocated in the booster cylinder chamber 14.

The booster cylinder chamber 14 has first and second chambers.
An oil passage connected to an oil passage 41a via an oil passage 42 having check valves 31 and 32, a drain via an oil passage 45 having a first pilot check valve 33, and further having a second pilot check valve 34. It is connected to the working cylinder chamber 81 of the clamp tool 80 via 44. The oil passage 44 can be freely connected to the clamp tool 80, so that a plurality of tools can be exchanged and used.

When the clamp tool 80 is used in the hydraulic booster device having such a configuration, first, the right solenoid 2 of the operation switching valve 1 is excited to move the solenoid to the left (this position is referred to as an operation position. Mode is referred to as an operation mode). Thereby, the hydraulic oil from the hydraulic pump P is supplied from the operation switching valve 1 to the shuttle valve 20 through the oil passage 41a, and the shuttle ball 21 is moved leftward to be supplied to the left cylinder chamber 12 through the oil passage 41c. You. Upon receiving this oil pressure, the double-acting piston 11 is moved rightward together with the booster piston 15, and the hydraulic oil in the right cylinder chamber 13 is discharged to the drain via the oil passages 43a and 43b (and the double-acting control valve 17). Cylinder chamber 1
4 is supplied to the oil passage 44.

Here, a first pilot oil passage 51 connecting the oil passage 41b and the first pilot check valve 33 is connected to the drain via the operation switching valve 1, and the right cylinder chamber 1
Since the second pilot oil passage 52 connecting the valve 3 and the check valve 33 is also connected to the drain, the first pilot check valve 33 is closed by a spring force. On the other hand, hydraulic oil is supplied to a third pilot oil passage 53 connecting the oil passage 41a and the second pilot check valve 34,
Since the second pilot oil passage 52 is also connected to the second pilot check valve 34, the second pilot check valve 34 is normally closed by a spring force. In this state, as described above, the oil passage 4
4 is supplied with hydraulic oil, the hydraulic pressure of the hydraulic oil acts on the second check valve 32 and the first and second pilot check valves 33 and 34. At this time, since this hydraulic pressure acts to further close the second check valve 32 and the first pilot check valve 33, the second pilot check valve 34 is opened by receiving this hydraulic pressure, and the hydraulic oil is stored in the working cylinder chamber 81. Is supplied.

When the double-acting piston 11 moves to the right stroke end, the double-acting control valve 17 is switched, the oil passage 41d communicates with the oil passage 43a, and the working oil is also supplied to the right cylinder chamber 13. Here, the pressure receiving area of the right cylinder chamber 13 is set to be larger than the pressure receiving area of the left cylinder chamber 12, and the moving direction of the double-acting piston 11 is reversed by this pressure receiving area difference, and the piston 11 is now moved left. In response to this, the booster piston 15 also moves to the left, and starts sucking hydraulic oil into the booster cylinder chamber 14.

In this state, the first pilot oil passage 51 is connected to the drain, and the second and third pilot oil passages 52,
Since hydraulic oil is supplied to 53, the first pilot check valve 33 is closed by receiving this hydraulic pressure difference. On the other hand, the pilot oil pressure acting on the second pilot check valve 34 is equal, but the spring force and the oil pressure in the working cylinder chamber 81 act to close the same. Therefore, when the booster piston 15 moves to the left, the first and second check valves 31 and 32 are opened in accordance with this movement, and the hydraulic oil in the oil passage 41a is supplied to the booster cylinder chamber 14.
Introduce within.

When the double-acting piston 11 moves to the left stroke end in this way, the double-acting control valve 17 switches, and the oil passage 41d is closed and the oil passage 43a is closed.
Is connected to the drain, and the double-acting piston 11 starts rightward again. Hereinafter, the double-acting cylinder 11 is continuously reciprocated in this manner, and the working cylinder chamber 8 of the clamp tool 80 is moved.
An ultra-high pressure hydraulic oil is supplied into 1. When the working oil is supplied into the working cylinder chamber 81 in this way, the working piston 82 gradually moves to the right, and the moving clamp 84
Moves in the direction approaching the fixed clamp 85, and the object is clamped by the clamps 84 and 85. In such a clamping operation, when the hydraulic pressure in the working cylinder chamber 81 reaches a predetermined high pressure and the clamping force reaches a predetermined value,
It is set so that the relief valve 25 is opened and the pressure switch 27 is turned on.

When the pressure switch 27 is turned on,
The right solenoid 2 of the operation switching valve 1 is demagnetized, the left solenoid 3 is excited, and the operation switching valve 1 is moved to the right (this position is called a release position, and the following modes are called release modes). Therefore, the hydraulic oil from the hydraulic pump P is supplied to the oil passage 41b, and the oil passage 41a is connected to the drain.
The hydraulic oil supplied to the oil passage 41b moves the shuttle ball 21 to the right and is supplied to the left cylinder chamber 12 via the oil passage 41c. Therefore, even when the operation switching valve 1 is switched in this manner, the double-acting piston 11 is continuously reciprocated in the same manner as described above.

However, since the operating oil pressure states of the oil passages 41a, 41b are reversed, the first and second pilot oil passages 5
The hydraulic states of the first and second pilot check valves 33 and 34 are different from those described above. First, when the double-acting piston 11 moves rightward, the first pilot check valve 33 is always opened and the second pilot check valve 34 is closed by spring force. Therefore, hydraulic oil discharged from the booster cylinder chamber 14 with the rightward movement of the booster piston 15 is discharged to the drain via the first pilot check valve 33 and is not supplied to the clamp tool 80.

When the double-acting piston 11 is moved to the left, hydraulic oil is supplied to the second pilot oil passage 52. Therefore, the first pilot check valve 33 is closed by a spring force, and the second pilot check valve 34 is closed.
Is always open. Therefore, the hydraulic oil in the working cylinder chamber 81 is forcibly sucked into the booster cylinder chamber 14 with the leftward movement of the booster piston 15. At this time, the suction action also acts on the first and second check valves 31 and 32, but the first check valve 31 is kept closed by the spring force.

As described above, when the pressure switch 27 is turned on and the operation switching valve 1 is moved to the right, the hydraulic oil in the operation cylinder chamber 81 is discharged according to the reciprocating motion of the double-acting piston 11. And is discharged to the drain. Therefore, the moving clamp 84 of the clamp tool 80
Can be quickly returned to the release position, and the next clamping operation can be started immediately.

Next, a second embodiment of the present invention will be described with reference to FIG. Note that the same components as those of the first embodiment shown in FIG. As can be seen by comparing FIGS. 1 and 2, the hydraulic booster device of FIG. 2 includes third and fourth pilot check valves 35 and 36 instead of the first and second pilot check valves 33 and 34 of FIG. Only the configuration provided is different, and description of the same components will be omitted as much as possible. Third and fourth pilot check valves 35, 3
Numeral 6 is a check valve that is disposed in each of the oil passages 45 and 44 and that is released when receiving a pilot oil pressure from the oil passage 41b via the fourth pilot oil passage 54.

Also in this hydraulic booster device, when the clamp tool 80 is used, first, the right solenoid 2 of the operation switching valve 1 is excited to move the solenoid 2 to the left to be positioned at the operation position. As a result, the operating oil from the hydraulic pump P is supplied from the operation switching valve 1 to the left cylinder chamber 12 through the oil passage 41a, the shuttle valve 20, and the oil passage 41c, and moves the double-acting piston 11 to the right together with the booster piston 15. . Thereby, the booster cylinder chamber 14
Is supplied to the oil passage 44. At this time, since the fourth pilot oil passage 54 is connected to the drain, the hydraulic oil supplied to the oil passage 44 is supplied to the operation cylinder chamber 81 by opening the fourth pilot check valve 36.

When the double-acting piston 11 moves to the right stroke end, the double-acting control valve 17 is switched, and FIG.
As in the case of, the moving direction of the double-acting piston 11 is reversed, and the piston is moved left. In response to this, the booster piston 15 also moves to the left, and introduces hydraulic oil into the booster cylinder chamber 14 via the oil passage 42 having the first and second check valves 31 and 32. Thereafter, when the double-acting piston 11 moves to the left stroke end, the double-acting control valve 17 is switched, and the double-acting piston 11 starts to move right again. Less than,
In this way, the double-acting cylinder 11 is continuously reciprocated, and the ultrahigh-pressure hydraulic oil is supplied into the working cylinder chamber 81 of the clamp tool 80.

When the clamp operation is performed in this manner, the clamp force reaches a predetermined value, the relief valve 25 is opened, and the pressure switch 27 is turned on, the right solenoid 2 of the operation switching valve 1 is demagnetized to the left solenoid. 3 is excited, and the operation switching valve 1 is moved rightward to be in the release position. In the release mode, the hydraulic oil from the hydraulic pump P is supplied to the oil passage 41b and further supplied to the left cylinder chamber 12. Therefore, even in this case, even when the operation switching valve 1 is switched, the double-acting piston 11 is continuously reciprocated in the same manner as described above.

However, at this time, the operating oil pressure is supplied to the fourth pilot oil passage 54 from the oil passage 41b, and the third and fourth pilot check valves 35 and 36 are always opened.
For this reason, in the release mode, the hydraulic oil in the working cylinder chamber 81 of the clamp tool 80 is always in the third open state.
And, it is in a state of always communicating with the drain via the fourth pilot check valves 35 and 36. Therefore, the working oil in the working cylinder chamber 81 is discharged to the drain via the oil passages 44 and 45.

However, this discharge is caused by the return spring 83 of the clamp tool 80, which is the same as in the case of the conventional apparatus shown in FIG. However, in the hydraulic booster device of FIG. 2, the booster piston 14 is reciprocated by the double-acting piston 11 even in the release mode. Therefore, when the double-acting piston 11 moves rightward,
The hydraulic oil discharged from the booster cylinder chamber 14 with the rightward movement of the booster piston 15 is discharged to the drain via the third pilot check valve 35 in an open state. When the double-acting piston 11 is moved leftward, the booster piston 15 moves leftward, so that the booster cylinder chamber 14 moves.
The working oil in the working cylinder chamber 81 is forcibly sucked.

As described above, in the case of the hydraulic booster device of FIG. 2, when the pressure switch 27 is turned on and the operation switching valve 1 is moved to the right, the operation cylinder chamber 81 communicates with the drain, and The working oil is discharged from the working cylinder chamber 81 at first. However, this discharge may cause a problem that the release of the clamp tool 80 is slow (the return of the movable clamp 84 is slow) when the oil temperature is low. Accordingly, the hydraulic oil in the working cylinder chamber 81 is sucked into the booster cylinder chamber 14 and discharged to the drain. For this reason, the moving clamp 84 of the clamp tool 80 can be quickly returned to the release position,
The next clamping operation can be started immediately. That is, in this device, when the hydraulic pressure in the working cylinder chamber 81 is high, the fluid flows directly to the drain under its own pressure, and when the hydraulic pressure is low and the viscosity is high at a low temperature, the booster piston 15 is assisted by suction. Borrowing, that is, forcibly discharging the hydraulic oil is also performed in parallel, and the release speed of the clamp tool 80 is increased.

Next, a third embodiment of the present invention will be described with reference to FIG. The same components as those of the first embodiment shown in FIGS. 1 and 2 are denoted by the same reference numerals and described. As can be seen by comparing FIGS. 2 and 3, the hydraulic booster device of FIG. 3 differs only in the configuration of the pilot oil passage supplied to the third and fourth pilot check valves 35 and 36 of FIG. Is the same as that of the apparatus shown in FIG. Therefore, description of the same components will be omitted as much as possible.

First, the third pilot check valve 35
Is constituted by a check valve which is released when receiving a pilot oil pressure from the oil passage 41b via the fifth pilot oil passage 55. On the other hand, the fourth pilot check valve 36 is constituted by a check valve which is released when receiving a pilot oil pressure from the eighth pilot oil passage 58. However, the eighth pilot oil passage 58 is selectively connected to the oil passage 41b and the drain via the pilot switching valve 28, and the pilot switching valve 28 is connected to the right cylinder chamber 13
From the sixth pilot oil passage 56 and the oil passage 41
The switching operation is performed based on the hydraulic pressure from the seventh pilot oil passage 57 connected to a.

Also in this hydraulic booster device, when the clamp tool 80 is used, first, the right solenoid 2 of the operation switching valve 1 is excited and moved to the left to the operating position, and the operation from the hydraulic pump P is started. Oil is supplied to the left cylinder chamber 12, and the double-acting piston 11 is moved rightward together with the booster piston 15. As a result, the operating oil in the booster cylinder chamber 14 is supplied to the oil passage 44, and the fourth pilot check valve 36 is opened to open the operating cylinder chamber 8
1 is supplied.

When the double-acting piston 11 moves to the right stroke end, the moving direction of the double-acting piston 11 is reversed by the operation of the double-acting control valve 17 and is moved left. In response to this, the booster piston 15 also moves to the left, and introduces hydraulic oil into the booster cylinder chamber 14 via the oil passage 42 having the first and second check valves 31 and 32. Thereafter, when the double-acting piston 11 moves to the left stroke end,
The double-acting control valve 17 is switched, and the double-acting piston 11 starts to move right again. Hereinafter, the double-acting cylinder 11 is continuously reciprocated in this manner, and the ultrahigh-pressure hydraulic oil is supplied into the working cylinder chamber 81 of the clamp tool 80.

When the clamping force reaches a predetermined value and the relief valve 25 is opened to turn on the pressure switch 27, the right solenoid 2 of the operation switching valve 1 is demagnetized and the left solenoid is actuated. 3 is excited, and the operation switching valve 1 is moved rightward to be in the release position. In the release mode, the hydraulic oil from the hydraulic pump P is supplied to the oil passage 41b and further supplied to the left cylinder chamber 12. Therefore, even in this case, even when the operation switching valve 1 is switched, the double-acting piston 11 is continuously reciprocated in the same manner as described above. At this time, the operating oil pressure is supplied from the oil passage 41b to the fifth pilot oil passage 55, and the third pilot check valve 35 is always opened.

First, when the double-acting piston 11 is moved to the right, both the sixth and seventh pilot oil passages 56 and 57 are connected to the drain, so that the pilot switching valve 28 is moved upward by spring force, and the eighth pilot oil passage 58 is connected to the drain. Therefore, the fourth pilot check valve 36 is closed by receiving the hydraulic pressure of the working cylinder chamber 81,
Oil discharged from the booster cylinder chamber 14 is discharged to the drain through a third pilot check valve 35 which is always open.

On the other hand, when the double-acting piston 11 is moved to the left, hydraulic oil is supplied to the sixth pilot oil passage 56, the pilot switching valve 28 is moved downward, and from the oil passage 41b to the eighth pilot oil passage 58. The hydraulic oil is supplied, and the fourth pilot check valve 36 is opened. Therefore, the hydraulic oil in the working cylinder chamber 81 is sucked into the booster piston chamber 14 according to the leftward movement of the booster piston 15.
Hereinafter, this operation is repeated, and the operating oil in the operating cylinder chamber 81 is discharged to the drain directly via the third pilot check valve 35 or by the suction effect of the booster piston 15.

As described above, in the case of the hydraulic booster device of FIG. 3, in the release mode, the booster piston 15
During the return stroke, the working cylinder chamber 81 communicates with the drain to discharge the working oil, and the working oil in the working cylinder chamber 81 is sucked into the booster cylinder chamber 14 and discharged to the drain. Therefore, the moving clamp 84 of the clamp tool 80 can be quickly returned to the release position, and the next clamping operation can be started immediately.

[0039]

As described above, according to the present invention,
When the operation switching valve is in the operation mode, the opening and closing control of the opening and closing control valve group is performed so that the hydraulic oil discharged from the booster cylinder is supplied to the single-acting hydraulic actuator,
When the operation switching valve is in the release mode, the opening and closing control of the opening and closing control valve group is performed so that the hydraulic oil is sucked from the single-acting hydraulic actuator by the booster cylinder and discharged to the drain side. In both the operation mode and the release mode, the double-acting cylinder is reciprocated to supply and discharge the hydraulic oil by the booster cylinder, and in the operation mode, the single-acting hydraulic actuator uses the discharge operation of the booster cylinder to discharge the oil. In the release mode, the hydraulic oil supplied to the single-acting hydraulic actuator can be sucked and discharged using the return operation (suction operation) of the booster cylinder. Therefore, even when the operating oil temperature is low, the release operation of the single-acting hydraulic actuator can be quickly performed in a short time.

When the operation switching valve is in the release mode, the hydraulic oil is sucked from the single-acting hydraulic actuator through the second oil passage by the booster cylinder to drain while the third oil passage is always opened to the drain side. The opening / closing control of the opening / closing control valve group may be performed so as to be discharged to the side. In this case, the hydraulic oil supplied to the single-acting hydraulic actuator is discharged from the third oil passage by itself. When,
The hydraulic oil can be quickly discharged by using the function of discharging the booster cylinder by suction, and in this case, the release operation of the single-acting hydraulic actuator can be performed quickly in a short time.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram showing a hydraulic booster device according to a first embodiment of the present invention.

FIG. 2 is a hydraulic circuit diagram showing a hydraulic booster device according to a second embodiment of the present invention.

FIG. 3 is a hydraulic circuit diagram showing a hydraulic booster device according to a third embodiment of the present invention.

FIG. 4 is a hydraulic circuit diagram showing a conventional hydraulic booster device.

[Explanation of symbols]

 P Hydraulic pump 1 Operation switching valve 10 Booster mechanism 11 Double acting piston 15 Booster piston 20 Shuttle valve 27 Pressure switch 80 Clamp tool

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Norihisa Takahashi 1152, Yamashita, Ryoke, Ryoji, Ageo City, Saitama Prefecture Inside Aichi Corporation Ageo Works No. 10 Aichi Corporation Ageo Works (72) Inventor Yoshio Tagami 414-1 Shinjimura, Tone-gun, Gunma Prefecture, Japan 414-1 Higashimine Sukawa Aichi Corporation Shinji Works, Inc. 414-1 Higashimine Sugawa Inside Aichi Corporation Shinji Works

Claims (2)

[Claims] 1. A hydraulic booster device for supplying hydraulic oil to operate a single-acting hydraulic actuator, discharging the supplied hydraulic oil to a drain side, and releasing the single-acting hydraulic actuator. A booster means having a double-acting cylinder which is reciprocally operated upon receiving and a booster cylinder which is reciprocated while being connected to the double-acting cylinder; a first oil passage connecting a hydraulic oil supply source and the booster cylinder A second oil passage that connects the booster cylinder to the single-acting hydraulic actuator; a third oil passage that connects the hydraulic booster cylinder to the drain side; and a second oil passage that is disposed in the first to third oil passages. An opening and closing control valve group for controlling the opening and closing of a road; an operation mode for controlling the operation of the opening and closing control valve group to operate the single-acting hydraulic actuator; An operation switching valve for controlling switching to a release mode. When the operation switching valve is in the operation mode, the operating oil discharged from the booster cylinder is supplied to the single-acting hydraulic actuator. In a release mode, the hydraulic booster device performs opening / closing control of the opening / closing control valve group so that the booster cylinder sucks hydraulic oil from the single-acting hydraulic actuator and discharges it to the drain side. 2. When the operation switching valve is in a release mode, the third oil passage is always opened to a drain side.
2. The open / close control of the open / close control valve group so that the booster cylinder sucks hydraulic oil from the single-acting hydraulic actuator through the second oil passage and discharges the hydraulic oil to a drain side. The hydraulic booster device as described.