JPH09306305A - Fluid pressure driving device, and circuit breaker using this - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable fluid pressure driving device which can prevent a malfunction by biting-in of a foreign matter. SOLUTION: A fluid pressure driving device is provided with a fluid pressure actuating mechanism such as a piston 2 and a fluid pressure cylinder 3 to open and close a contactor 1, a fluid pressure pump 6 to pressurize and supply a working fluid to actuate the fluid pressure actuating mechanism and a control means such as a closed circuit control valve 13 and an open circuit control valve 15 to control opening-closing operation of the contactor through the fluid pressure actuating mechanism by controlling the flow of the working fluid from the fluid pressure pump 6. Among the closed circuit control valve 13 or the open circuit control valve 15, at least one control valve has a fitting hole 47 in an upstream part of a valve seat 44 so as to be slidably fitted to a valve body to prevent biting-in of a foreign matter in a closing operation stroke just before blocking up the valve seat 44 when the valve body comes into contact with the valve seat 44.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid pressure drive device, and more particularly to a circuit breaker using the fluid pressure drive device which avoids malfunction due to foreign matter being caught.

[0002]

2. Description of the Related Art In a fluid pressure drive device used for a circuit breaker provided for instantaneously shutting off a large amount of electric power to protect an electric power system, after a circuit opening operation or a circuit closing operation, unless a correct operation command is issued, That state must be maintained, and never open or close without permission. However, if a foreign substance is generated inside the fluid pressure drive device for some reason and this foreign substance gets caught in the valve seat of the open control valve or the close control valve, and the valve body becomes unable to control the working fluid, the operation command is not affected. There is a possibility that the circuit breaker may malfunction due to opening or closing.

For this reason, in the conventional fluid pressure drive device, a structure for preventing malfunction by providing a filter for removing foreign matter has been used.

[0004]

With the above-mentioned configuration of the prior art, it is possible to remove the foreign matter generated upstream of the filter, but the foreign matter generated between the filter downstream side and the control valve cannot be eliminated. There is a risk of malfunction due to the possibility of entering the valve seat and biting into the valve seat. Therefore, an object of the present invention is to solve the problems of the above-mentioned conventional techniques and prevent malfunctions due to foreign matter entrapment.
A highly reliable fluid pressure drive device and a circuit breaker using the same.

[0005]

The features of the present invention for achieving the above object are a fluid pressure operating mechanism for opening and closing a contact, and a fluid pressure source for pressurizing and supplying a working fluid for operating the fluid pressure operating mechanism. And a control means for controlling the opening / closing operation of the contactor via the fluid pressure operating mechanism by controlling the flow of the working fluid from the fluid pressure source. , A closing control valve or a closing control valve, and at least one of the control valves has a valve body that abuts against the valve seat and closes the valve seat. A fitting hole that slidably fits into the valve body is provided at a position upstream of the valve seat so as to prevent slipping.

Further, the fitting hole has a fitting gap t3 between the fitting hole and the valve body, and the fitting gap t3 is a predetermined depth from the upper edge of the fitting hole in the closing direction in the closing operation direction. It is set to be smaller than the clearance t4 of the valve seat.

A circuit breaker which achieves the object is the claim 1.
Further, the fluid pressure drive device according to any one of claims 1 to 2 is used.

According to the present invention, the fitting hole serves as a filter, foreign matter is prevented from being caught in the valve seat of each control valve, and malfunction of the fluid pressure drive device is prevented. A device and a circuit breaker are provided.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings of FIGS. An embodiment of foreign matter entrapment prevention means as a malfunction prevention mechanism of the fluid pressure drive device when the fluid pressure drive device according to the present invention is used for a power circuit breaker will be described. FIG. 1 is a structural view showing a closed state of a fluid pressure drive device according to an embodiment of the present invention. The configuration of the fluid pressure drive device shown in the figure is such that a fluid pressure actuating mechanism including a piston 2 and a fluid pressure cylinder 3 for opening and closing the contact 1 and a fluid pressure for supplying a working fluid for actuating the fluid pressure actuating mechanism under pressure. A fluid pressure pump 6 as a source, and a closing control valve 13 and an opening control valve as control means for controlling the flow of a working fluid pressurized by the fluid pressure pump 6 to control the operation of the fluid pressure operating mechanism. It consists mainly of fifteen and so on.

Next, the operation will be described. High pressure is constantly supplied to the operation chamber 4a on the small pressure receiving area side of the fluid pressure cylinder 3 having the piston 2 that opens and closes the contactor 1 from the fluid pressure pump 6 and the accumulator 7 that are fluid pressure sources via the supply port 5. It On the other hand, the operation chamber 4b on the large pressure receiving area side
A control port 9 of the main control valve 8 is connected to the control port 9 to supply and discharge the working fluid to and from the operation chamber 4b. At this time,
By supplying the working fluid to the operation chamber 4b, the contactor 1 closes, and by discharging the working fluid, the contactor 1 opens.

The main control valve 8 is controlled by constantly applying a high pressure to the back surface of the poppet valve on the side of the supply port 10 connected to the supply port 5 and supplying and discharging the working fluid to and from the main control valve pilot chamber 12. Port 9 is selectively connected to supply port 10 or return port 11. The main control valve 8 includes a closing control valve 13 and a closing pilot valve 14.
The valve is switched to the closing operation position by the closing operation system valves, and the opening control position is changed by the opening control system valves including the opening control valve 15 and the opening pilot valve 16. Further, the main control valve pilot chamber 12 communicates with the control port 9 that communicates with the operation chamber 4b of the fluid pressure cylinder 3 through the throttle 17.
It is connected to the.

The valve bodies of the closing control valve 13 and the opening control valve 15 each have a large-diameter portion, a medium-diameter portion, and a small-diameter portion, and a poppet valve is formed at the tip of the valve body of the medium-diameter portion. . The large diameter portion is connected to the supply port through the throttles 18 and 19, and is also connected to the primary side 20 and 21 of the closing pilot valve 14 and the opening pilot valve 16 in the first pilot chambers 22 and 2 respectively.
At 3, when a high pressure acts, a force for closing each control valve is generated. A second pilot chamber 24, 25 is formed between the large-diameter portion and the medium-diameter portion, which is connected to the supply port so that a high pressure is constantly applied to generate a force for opening each control valve.

The bottom of the valve body at the tip of the valve element at the middle diameter of the closing control valve 13 and the opening control valve 15 comes in contact with the valve seats 44 and 45, and a hole for containing the valve body is formed. Fitting holes 46 and 47 formed with a constant inner diameter are provided so as to be slidably fitted in the valve body of the control valve. The primary side 26 of the poppet valve portion of the closing control valve 13 is connected to the supply port, and the secondary side 27 is connected to the main control valve pilot chamber 12 via a check valve 28. On the other hand, it is connected to the return port 30 via the diaphragm 29. Open control valve 1
The primary side 31 of 5 is connected to the main control valve pilot chamber 12, and the secondary side 32 is connected to the return port 30. The secondary sides 33, 34 of the closing pilot valve 14 and the closing pilot valve 16 are connected to the return port 35, and are pushed by the closing driving means 36 and the opening driving means 37 to perform the opening operation, respectively. It is pushed by 38 and 39 to perform a closing operation.

On the other hand, the primary side 21 of the open-circuit pilot valve 16 communicating with the first pilot chamber 23 of the open-circuit control valve 15.
A lock valve 41 is provided on the flow path connecting the return port 40 and the return port 40. The locking valve 41 can always perform the opening operation even if some abnormality occurs in the fluid pressure drive device, and further disables the next closing operation. Lock valve 41
Is composed of a large diameter portion, a medium diameter portion, and a small diameter portion. A poppet valve is formed at the tip of the medium diameter portion, and the primary side has an open control valve 1
5, the open side pilot valve 16 communicating with the first pilot chamber 23 is connected to the primary side 21 and the secondary side to the return port 40.

The lock valve 41 includes a first pilot chamber 42 that applies pressure to a small diameter portion, a second pilot chamber 43 that applies pressure between a large diameter portion and a small diameter portion, and a large diameter portion and a medium diameter portion. There is a third pilot chamber 50 that applies a pressure between them to generate a force that opposes the first and second pilot chambers. First
The pilot chamber 42 is the primary side 2 of the closing pilot valve 14.
0, and the second pilot chamber 43 has the open control valve 1
5 is connected to the primary side 21 of the open-circuit pilot valve 16 communicating with the first pilot chamber 23, and the third pilot chamber 50
Is connected to the supply port.

The third pilot chamber 50 is maintained at a high pressure and pushes the locking valve 41 upward in the figure to generate a force for opening the valve. At least one of the first pilot chamber 42 and the second pilot chamber 43 is generated. When a high pressure acts on either one of them, the locking valve 41 can be pushed downward in the drawing to generate a force for closing the valve. The fluid pressure pump 6 is for storing high-pressure working fluid in the accumulator 7, and starts operation when the amount of working fluid stored in the accumulator 7 decreases and the pressure falls below a predetermined lower limit value. When the pressure recovers and reaches a predetermined upper limit value, the operation is stopped. Therefore, when the control means and the piston 2 operate, they are mainly supplied from the accumulator 7 via the supply port 5.

Next, the operation of the fluid pressure drive system of this embodiment will be described with reference to FIGS. In the closed state shown in FIG. 1, when the open command is issued, the open drive means 37 pushes the open pilot valve 16 to open it.
The working fluid flows out from the secondary side 21 to the secondary side 34. At this time, although it flows in from the supply port through the throttle 19, since the outlet side has a larger opening than the inlet side, the primary side 21 and the first pilot chamber 23 of the open circuit control valve 15 communicating therewith are The pressure becomes low, and the opening control valve 15 is opened by the operating force applied from the second pilot chamber 25.

When the open control valve 15 is opened, the working fluid in the main control valve pilot chamber 12 is discharged from the primary side 31 to the secondary side 32 to the return port 30 to become a low pressure.
The main control valve 8 is switched to the open operation position, the working fluid is discharged from the operation chamber 4b of the fluid pressure cylinder 3, and the piston 2
2 starts the circuit opening operation by the pressure acting on the operation chamber 4a on the small pressure receiving area side, and becomes the state shown in FIG.

The opening command is released, and the driving means 37 for opening is opened.
When the driving force is eliminated, the opening pilot valve 16 is pushed by the spring 39 and closed. Then, since the working fluid is supplied through the throttle 19 and the primary side 21 becomes high in pressure, the open-circuit pilot valve 16 is held closed more strongly and the first pilot chamber 23 of the open-circuit control valve 15 is also set to high pressure. Therefore, the operating force of the second pilot chamber 25 is overcome and the opening control valve is closed. However, since the main control valve pilot chamber 12 is connected to the control port 9 which has already become low pressure through the throttle 17, the main control valve 8 is kept in the open circuit operation position,
The piston 2 continues the open circuit operation to reach the open circuit holding state shown in FIG. 3, and the electric power is cut off.

When a closing command is issued in the open-circuit holding state shown in FIG. 3, the closing drive means 36 pushes the closing pilot valve 14 to open it, and the working fluid flows from the primary side 20 to the secondary side 33. At this time, although it flows in from the supply port through the throttle 18, the opening is larger on the outflow side than on the inflow side, so the primary side 20 and the first pilot chamber 22 of the closing control valve 13 communicating therewith are at a low pressure. Then, the closing control valve 13 is opened by the operating force applied from the second pilot chamber 24.

When the closing control valve 13 is opened, the supply port 4 is opened.
Since the working fluid is supplied from 9 through the primary side 26, the secondary side 27 and the check valve 28 and the inside of the main control valve pilot chamber 12 becomes high pressure, the main control valve 8 is switched to the closed operation position, The working chamber 4 of the fluid pressure cylinder 3 is supplied with working fluid.
Since b becomes high in pressure, the piston 2 starts the closing operation by overcoming the force generated by the operation chamber 4a, and the fluid pressure drive device becomes the state shown in FIG.

The closing command is released, and the closing driving means 36
When the driving force is eliminated, the closing pilot valve 14 is pushed by the spring 38 and closed. Then, the working fluid is supplied through the restrictor 18 and the primary side 20 has a high pressure. Therefore, the closing pilot valve 14 is kept closed more strongly and the first pilot chamber 22 of the closing control valve 13 is also set to a high pressure. Therefore, the closing control valve 13 is closed by overcoming the operating force of the second pilot chamber 24. However, the main control valve pilot room 1
Since 2 is connected to the already-high-pressure control port 9 via the throttle 17, the main control valve 8 is kept in the closing operation position, and the piston 2 continues the closing operation.

Further, the check valve 28 has the main control valve 8 completed the switching to the closing operation position and the main control valve pilot chamber 1
When 2 becomes almost equal to the supply pressure, it is pushed by the spring and closed, so that even if the closing control valve 13 is closed, the main control valve pilot chamber 12 is kept at high pressure, while the inflow from the primary side 26 When stopped, the secondary side 27 flows out to the return port 30 via the throttle 29, and the secondary side 27 becomes a low pressure. Thus, FIG.
The circuit is in the closed state as shown in, and the power is turned on.

Next, the operation of the malfunction prevention structure of this embodiment will be described with reference to FIGS. FIG.
FIG. 6 is an enlarged view showing an open position holding state of a closing control valve of an embodiment according to the present invention. 5 to 7 are enlarged views of the closing control valve 13 shown in FIGS. 1 to 4. The same applies to the opening control valve 15 instead of the closing control valve 13.

The poppet valve portion of the control valve is the closing control valve 1
Since 3 and the opening control valve 15 have the same structure, the closing control valve 13 will be described as an example here. Therefore, the reference numerals in FIGS. 5 to 7 correspond to the reference numerals of the closing control valve 13. In addition, FIG. 8 is an enlarged view showing a state in which the valve body and the valve seat portion are held in the open position in the embodiment of FIG. 8 to 11 are valve bodies of the control valve shown in FIGS.
It is an enlarged version of the valve seat.

In FIG. 1, it is assumed that, for some reason, foreign matter is generated from the supply port inside the fluid pressure drive device at the supply port 49 on the primary side of the closing control valve. Possible foreign substances include burrs that are generated during processing of the pipeline of the fluid pressure drive device and are separated by the flow of the working fluid, and metal powder due to sliding friction when the valve body operates. The generated foreign matter moves inside the device due to the flow of the working fluid, and eventually reaches the primary side 26 near the poppet valve portion.

In FIG. 5, when a closing command for closing the contact 1 causes the closing control valve 13 to start opening due to the operation of each valve described above, the valve opens and the working fluid flows to the secondary side 27. After the opening operation of the control valve is completed, the control valve starts the closing operation by supplying the high pressure to the first pilot chamber 22. Most of the foreign matter in the fluid pressure drive device is swept away by the working fluid, but if the foreign matter is present in the valve seat when the control valve is closed, when the valve body of the control valve is seated on the valve seat. There is a possibility that the fluid pressure drive device may be bitten in and may cause a malfunction of the fluid pressure drive device.

According to the present invention, the fitting for slidably fitting the valve body so as to prevent foreign matter from being caught in the closing operation stroke immediately before the valve body contacts the valve seat and closes the valve seat. A hole is provided upstream of the valve seat, and a foreign matter biting prevention means is formed in the structural portion of the fitting hole and the valve body to fulfill the filter function and prevent foreign matter biting accidents. It is an object. Details of the structural portion of the fitting hole and the valve body as the foreign matter entrapment preventing means will be described with reference to FIGS. 8 to 11.

FIG. 8 is an enlarged view showing a state where the “valve body and valve seat” portion in the embodiment of FIG. 5 is held in the open position. That is, in the relationship between the “valve element and the valve seat”, the valve element is in the fully open state in which it is farthest from the valve seat. It is assumed that the valve body starts the closing operation from this fully opened state and the valve body has reached the state position shown in FIG.

In the state of FIG. 9, the upstream gap between the valve body 13a of the closing control valve 13 and the upper edge 60 of the fitting hole 47 is t1, and the gap between the valve body 13a and the valve seat 44 is t2. Then,
The following relationship is always established between t1 and t2. t1 <t2 (Equation 1) This is because the fitting hole 47 according to the present invention slides the valve body 13a in the closing operation stroke before the valve body 13a abuts the valve seat 44 and closes the control valve. This is because the fitting hole 47 that is movable and that fits into the valve body 13a is provided at a position upstream of the valve seat. In other words, in the case of the structure without the fitting hole 47 (as shown by the virtual dotted line in FIG. 9), in proportion to the closing stroke of the valve body 13a until the valve body 13a contacts the valve seat 44, The gap t2 simply decreases. Therefore, if there is a foreign substance, it may be caught by the valve seat 44 having the clearance t2 and the foreign substance may be caught.

On the other hand, in the case of the present invention, since the fitting hole 47 is provided, the relationship of t1 <t2 is established, and (1) if the size of the foreign matter is larger than t1, the foreign matter is in the upstream clearance. It is not caught at t1 and does not enter in the direction of the valve seat 44. (2) If the size of the foreign matter is smaller than t1, t1 <
Since it is t2, the foreign matter passes through both the upstream clearance t1 and the clearance t2, and in this case also, the foreign matter does not get caught in the valve seat 44. By providing the fitting hole 47 in this manner, the structural portion of (the fitting hole upper edge 60 of) the fitting hole 47 and the valve body 13a serves as a filter. The fitting hole 47 is preferably formed by directly forming a hole in the valve seat main body from the viewpoint of manufacturing, but it may be formed by press-fitting a separate seat.

In other words, the foreign matter entrapment prevention means according to the present invention, when the valve body 13a is in the closing operation stroke of closing the valve seat 44, the original "valve portion composed of the valve body and valve seat" Also at the upstream portion, at the valve portion, that is, the valve body 13a and the valve seat
Therefore, the upstream clearance t having a size smaller than the clearance t2 to be formed.
1 is formed between the valve body 13a and the valve body 13a, and for that purpose, a fitting hole 47 that can be fitted into the valve body 13a is formed. On the contrary, when the valve body 13a is not fitted in the fitting hole 47, the "valve portion including the valve body and the valve seat" is simply moved to the upstream portion, and the present invention intends to do so. It cannot act as a filter.

Further, it is assumed that the valve body continues the closing operation and reaches the state position shown in FIG. 10, that is, the fitting portion where the valve body and the valve seat literally fit together. In this state,
Assuming that the fitting gap of the fitting portion is t3 and the gap between the valve seat and the valve body is t4, the dimensions of the fitting hole 47 are set so that the following relationship holds for t3 and t4.

T3 <t4 (Equation 2) That is, in the case of the present invention in which the above relationship is established, (1)
If the size of the foreign matter is larger than the fitting gap t3, the foreign matter is caught in the fitting gap t3 and does not enter in the valve seat direction. (2) If the size of the foreign matter is smaller than the fitting gap t3, the foreign matter will be smaller than t4 and will pass through, so that it will not be caught in the valve seat 44.

However, from the upper edge 60 of the fitting hole to the valve body 1
The fitting gap 47 between the fitting hole 47 and the valve body 13a is a predetermined gap in the closing direction of the valve 3a (H dimension shown in FIG. 10). It is not set smaller than the fitting gap t4 formed between the valve body 13a and the valve seat 44 immediately before closing, in other words, t3 ≧ t.
In the case of the relationship of 4, the gap t3 is set to be narrow, but there is a risk that foreign matter that has passed through the gap t3 may get caught in the valve seat 44.

The following relationship is established between the upstream clearance t1 and the fitting clearance t3. t1> t3 (Equation 3) That is, in the operation process of the valve body, it is possible to enter the valve seat 44 by setting the relationship of t1> t3 (strictly speaking, t1 (min) = t3). This is because the size of the foreign matter having the property can be restricted to a smaller value, and the filter plays a more reliable role. And finally, the valve body 13a is a fitting portion of a certain length.
(That is, from the upper edge 60 of the fitting hole described above to a predetermined depth H in the sliding movement direction of the valve body 13a), the valve body 13a is seated on the valve seat 44 as shown in FIG. The operation of the control valve is completed.

The sizes of the upstream clearance t1 and the fitting clearance t3 are set according to the size of foreign matter that can enter the valve seat.
In the present embodiment, considering the size of the metallic foreign matter actually bitten in the circuit breaker, the upstream clearance t1 is about 30 to 60 microns and the fitting clearance t3 is about 10 to 30 microns. It should be noted that if the upstream gap t1 is made too narrow to around 10 to 30 microns, the flow resistance of the working fluid increases, which is not preferable.

On the other hand, immediately before the valve element comes into contact with the valve seat and closes the control valve, there is always an operation process section where t3 ≧ t4. On the other hand, the size of the fitting gap t3 is
It can be said that the frequency of foreign matter entrapment is sufficiently reduced as compared with the conventional case if it is set based on the above-mentioned results.

From the above, the provision of the fitting hole 47 serves as a first-stage filter for removing foreign matter between the valve body 13a and the upper edge 60 of the fitting hole, and further, the valve body 13a. And the fitting portion of the fitting hole 47 serve as a second-stage filter, and the fluid pressure drive device has a double filter structure or a triple filter structure (including an external filter), so that foreign matter is caught in the valve seat. Can be prevented. Therefore, malfunction of the fluid pressure drive device can be prevented and reliability can be improved.

By the way, when the closing control valve 13 opens, the foreign matter caught on the first-stage filter or the second-stage filter is pushed away by the working fluid and flows away. Then, it is removed by the filter originally installed outside. Thus, it can be seen that the filter according to the present invention provided inside the fluid pressure drive device is maintenance-free.

In summary, the features of the present invention are: a fluid pressure cylinder for opening and closing the contact, a fluid pressure source for pressurizing and supplying the working fluid, and a flow of the working fluid supplied from the fluid pressure source. In a fluid pressure drive device including control means for controlling and driving a fluid pressure cylinder, the control means includes a closing operation system valve for guiding a contact to a closed state and an opening operation for guiding a contact to an open state. There is a system valve, and a means for preventing the foreign matter from being caught in the valve seat portion is used as a control valve inside the closing operation system valve or inside the opening control means. Specifically, each open or closed control valve is a poppet valve,
Since the valve seat is formed at the bottom and the hole for enclosing the valve body is formed with a constant inner diameter so that the valve body can slidably fit a predetermined length from the valve seat, the valve body is provided. It is possible to remove foreign matter having a size larger than the minute gap between the hole and the inner hole, and prevent foreign matter from being caught in the valve seat surface. Therefore, malfunction of the fluid pressure drive device can be prevented.

That is, since the valve body and the hole portion function as a filter, foreign matter generated on the primary side (upstream) of the portion can be prevented from entering the valve seat, and open / close control can be performed. (EN) A fluid pressure drive device and a circuit breaker which can prevent foreign matter from being caught in a valve seat of a valve, prevent malfunction, and have high reliability.

By the way, as another feature of the present invention, in a fluid control valve having a valve body and a valve seat, in the closing operation stroke immediately before the valve body contacts the valve seat and closes the valve seat, foreign matter It can be said that a fitting hole that slidably fits with the valve body is provided at a position upstream of the valve seat so as to prevent biting.

[0044]

According to the present invention, since the fitting hole 47 holds the foreign matter mixed in the fluid pressure drive device, the valve body 13a of the poppet valve and the valve seat 44 can be reliably seated. A malfunction of the drive device can be prevented, and a highly reliable fluid pressure drive device and circuit breaker can be realized.
Further, the foreign matter entrapment prevention means according to the present invention does not require maintenance, and since the valve seat body is simply drilled, the number of parts does not increase, so that the reliability of the fluid pressure drive device is improved. Similarly, cost reduction can be realized.

[Brief description of drawings]

FIG. 1 is a structural diagram showing a fluid pressure drive device (closed circuit holding state) according to an embodiment of the present invention.

FIG. 2 is a structural diagram showing an open circuit operation state in the embodiment of FIG.

FIG. 3 is a structural diagram showing an open circuit holding state in the embodiment of FIG.

FIG. 4 is a structural diagram showing a closed circuit operation state in the embodiment of FIG.

FIG. 5 is an enlarged view showing an open position holding state of a closing control valve according to an embodiment of the present invention.

FIG. 6 is an enlarged view showing a midway of the closing operation in the embodiment of FIG.

FIG. 7 is an enlarged view showing a closed position holding state in the embodiment of FIG.

FIG. 8 is an enlarged view showing an open position holding state of a “valve body and valve seat” portion in the embodiment of FIG.

FIG. 9 is a view showing the middle of the first closing operation of the valve body in the embodiment of FIG.

FIG. 10 is a view showing the middle of the second closing operation of the valve body in the embodiment of FIG.

FIG. 11 is a view showing a closed position holding state of the valve body and the valve seat portion in the embodiment of FIG.

[Explanation of symbols]

1 ... Contact, 2 ... Piston, 3 ... Fluid pressure cylinder, 4
... Operating chamber, 5, 10, 49 ... Supply port, 6 ... Fluid pressure pump, 7 ... Accumulator, 8 ... Main control valve, 9 ... Control port, 11, 30, 35, 40 ... Return port, 12 ... Main control valve Pilot chamber, 13 ... Control valve for closing, 13a ... Valve body, 14 ... Pilot valve for closing, 15 ... Control valve for opening,
16 ... Pilot valve for opening, 17, 18, 19, 29 ...
Apertures, 20, 21, 26, 31 ... Primary side, 22, 23,
42 ... 1st pilot chamber, 24, 25, 43 ... 2nd pilot chamber, 27, 32, 33, 34 ... Secondary side, 28 ... Check valve, 36 ... Closing drive means, 37 ... Opening drive means,
38, 39 ... Spring, 41 ... Locking valve, 44, 45 ... Valve seat,
46, 47 ... Fitting hole, 50 ... Third pilot chamber, 60 ...
Upper edge of mating hole

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideo Kawamoto 1-1-1 Kokubun-cho, Hitachi City, Hitachi, Ibaraki Prefecture Inside the Kokubun Plant of Hitachi, Ltd. (72) Inventor Tadahiko Nogami 502 Kandachi-cho, Tsuchiura-shi, Ibaraki Co., Ltd. Hiritsu Seisakusho Mechanical Research Laboratory (72) Inventor Hiroshi Maeda 1-1-1, Kokubun-cho, Hitachi-shi, Ibaraki Hitachi Kokubun Plant (72) Inventor Hiroyoshi Sadamura 1-1, Kokubun-cho, Hitachi-shi, Ibaraki No. 1 inside the Kokubun Plant of Hitachi, Ltd.

Claims (3)

[Claims] 1. A fluid pressure operating mechanism for opening and closing a contact, a fluid pressure source for pressurizing and supplying a working fluid for operating the fluid pressure operating mechanism, and a flow of the working fluid from the fluid pressure source. In the fluid pressure drive device having a control means for controlling the opening / closing operation of the contactor via the fluid pressure operation mechanism, the control means includes a closing control valve or an opening control valve, and the control At least one of the valves is slidably fitted to the valve body so as to prevent foreign matter from being caught in the closing operation stroke immediately before the valve body abuts the valve seat and closes the valve seat. A fluid pressure drive device having a fitting hole to be provided at a position upstream of the valve seat. 2. The fitting hole according to claim 1, wherein the fitting gap t3 between the fitting hole and the valve body is a predetermined depth from the upper edge of the fitting hole in the closing operation direction. The fluid pressure drive device is set to be smaller than a gap t4 between the valve body and the valve seat. 3. A circuit breaker using the fluid pressure drive device according to any one of claims 1 and 2.