JP6703585B2 - Fluid pressure controller - Google Patents

Description

The present invention relates to a fluid pressure control device.

In Patent Document 1, as a hydraulic drive for a construction machine, a first hydraulic pump and a second hydraulic pump that supply pressure oil for operating a boom cylinder and an arm cylinder, respectively, and a boom connected to the first hydraulic pump in parallel are provided. A first boom direction control valve for controlling the flow of pressure oil supplied to the cylinder and a second arm direction control valve for controlling the flow of pressure oil supplied to the arm cylinder, and a parallel connection to the second hydraulic pump. And a first arm directional control valve for controlling the flow of pressure oil supplied to the arm cylinder, and a second boom directional control valve for controlling the flow of pressure oil supplied to the boom cylinder. A hydraulic drive is disclosed.

This hydraulic drive device includes a third hydraulic pump that supplies pressure oil for operating the boom cylinder and the arm cylinder, and a third boom that is connected to the third hydraulic pump and that controls the flow of pressure oil supplied to the boom cylinder. Directional control valve and the third boom directional control valve are connected in tandem to control the flow of pressure oil supplied to the arm cylinders in parallel with the third boom directional control valve. And a second preliminary directional control valve connected to the third hydraulic pump.

In this hydraulic drive device, a second actuator for driving the second special attachment connected to the arm is provided, and the pressure oil of the third hydraulic pump is supplied to the second actuator via the second preliminary directional control valve. , The second special attachment can be driven.

JP 2012-241803 A

In the hydraulic drive system of Patent Document 1, the third boom direction control valve and the second preliminary direction control valve are connected to the third pump in parallel with each other. Therefore, when the third boom directional control valve and the second preliminary directional control valve are simultaneously operated, the flow rate of the working fluid supplied to the actuator controlled by the other changes due to the operation of the actuator controlled by the one. Therefore, when the third boom directional control valve and the second preliminary directional control valve are simultaneously operated, the operation of the actuators controlled by these control valves may become unstable.

In order to prevent such an unstable operation of the actuator, Patent Document 1 discloses that the pipeline portion that connects the third hydraulic pump and the second preliminary direction control valve is shut off, and the second preliminary direction control is performed. It is described that an additional hydraulic pump may be connected to the additional pump port of the valve via a pipe. According to this, the pressure oil of the additional hydraulic pump can be supplied to the actuator via the second preliminary directional control valve, and the special attachment can be driven independently of the boom operation and the like.

However, whether one control valve (spare directional control valve) is connected to the same pump as another control valve (boom directional control valve) in parallel, or is connected to another pump and is independent of the other control valve. Depends on the work machine installed and needs.

Further, the pump structure for supplying the working fluid differs depending on whether a certain control valve is connected to the same pump as the other pump in parallel or independently, so that the piping structure is also different.

Therefore, in the hydraulic drive device described in Patent Document 1, a hydraulic drive device having a plurality of piping structures must be manufactured according to the installed work machine, needs, etc., and the manufacturing cost increases.

The present invention has been made in view of the above problems, and an object thereof is to reduce the manufacturing cost of a fluid pressure control device.

The present invention relates to a first pump passage for guiding a working fluid discharged from a first pump, a second pump passage for guiding a working fluid discharged from a second pump, and an operation discharged from a first pump or a second pump. A main passage, through which fluid is selectively guided and communicates with the tank, a first control valve provided in the first pump passage for controlling the flow of working fluid supplied to and discharged from the first actuator, and a main passage provided in the main passage. A second control valve for controlling the flow of the working fluid supplied to and discharged from the two actuators, a supply passage branched from the main passage for guiding the working fluid to the second control valve, and a supply passage branched for the first pump passage. A parallel passage connected to the parallel passage, a check valve provided in the parallel passage for allowing only the flow of the working fluid from the first pump to the supply passage, and a main valve provided in the main passage out of the first pump passage and the second pump passage. A switching valve for selectively switching a passage communicating with the passage, wherein the switching valve has a first switching position for communicating the first pump passage and the main passage and a first switching position for communicating the second pump passage and the main passage. And two switching positions.

In the present invention, when the switching valve is set to the first switching position, the main passage for guiding the working fluid to the second control valve communicates with the first pump passage, and the second control valve discharges the operation fluid discharged from the first pump. Fluid is guided. Therefore, each of the first actuator and the second actuator operates by the working fluid discharged from the first pump. When the switching valve is in the second switching position, the main passage communicates with the second pump passage, and the working fluid discharged from the second pump is guided to the second control valve. Therefore, the first actuator operates independently of each other by the working fluid discharged from the first pump, and the second actuator operates independently of each other by the working fluid discharged from the second pump. In this way, by switching the position of the switching valve, it is possible to select whether to guide the working fluid from the first pump or the working fluid from the second pump to the second control valve. Therefore, the piping structure can be made common regardless of which of the first pump and the second pump the working fluid is introduced to the second actuator.

In the present invention, the first actuator is a fluid pressure cylinder that expands and contracts due to the pressure difference between the load side pressure chamber in which the load to be driven acts and the anti-load side pressure chamber, and the first control valve includes the first The second control valve has a first neutral position that opens the pump passage, and a drive position that opens the first pump passage and connects the first pump passage and the anti-load side pressure chamber. Has a second neutral position for communicating with the tank, and a supply position for supplying the working fluid guided from the supply passage to the second actuator, and the switching valve connects the second pump passage and the tank at the first switching position. A bypass cut valve that connects the first pump passage and the tank in the second switching position, and that connects the first pump passage downstream and the opening of the first pump passage is provided in the first pump passage. It is characterized by being.

In the present invention, the bypass cut valve opens the first pump passage in the state where the switching valve is in the first switching position and the second control valve is in the second neutral position, and in the state where the switching valve is in the second switching position. In addition, when the first control valve is set to the drive position, the first pump passage communicates with the tank. In this case, the working fluid discharged from the first pump is not supplied to the first actuator, and the first actuator operates by the weight of the load. On the other hand, when the first control valve is switched to the drive position in the state where the first pump passage is blocked by the bypass cut valve, the communication between the first pump passage and the tank is blocked, so that the first pump is discharged. The working fluid is supplied to the anti-load side pressure chamber of the first actuator. Therefore, the fluid pressure cylinder operates by the pressure of the working fluid discharged from the first pump. Thus, by providing the bypass cut valve that switches between opening and closing of the first pump passage, it is possible to drive the first actuator by both drive by load and drive by fluid pressure.

Further, the present invention further comprises a housing for accommodating the switching valve and the bypass cut valve, the switching valve having a first spool for switching the position, and the bypass cut valve having a second spool for switching the position. The first spool of the valve and the second spool of the bypass cut valve are coaxially housed in the housing hole formed in the housing so as to face each other.

In the present invention, the housing can be made compact.

Further, according to the present invention, the accommodation hole is formed as a through hole having both ends opened to the end surface of the housing, and the switching valve is attached to the housing, and the first cap seals one opening of the accommodation hole, and the first cap. An internal pressure chamber formed therein, a first urging member provided in the first cap for urging the first spool in a direction away from the second spool, and provided in the first cap, the first urging member being manually operated. The bypass cut valve further includes a switching portion that moves the first spool against the urging force of the urging member, and the bypass cut valve includes a second cap that is attached to the housing and seals the other opening of the accommodation hole; A pilot chamber formed in the second cap and in which a pilot pressure for urging the second spool toward the first spool is guided through a pilot port; and a direction provided in the second cap to separate the second spool from the first spool. And a second urging member that urges toward.

Further, according to the present invention, the first cap is provided with an introduction port for guiding a pilot pressure for moving the first spool to the internal pressure chamber against the urging force of the first urging member, and the internal pressure chamber in the first cap is formed. Is always in communication with the tank through the drain passage, and the drain passage is provided with a throttle portion that imparts resistance to the flow of the working fluid passing therethrough.

Further, according to the present invention, the drain passage has an internal space defined in the accommodation hole by the end portion of the first spool and the end portion of the second spool that face each other, and the internal pressure chamber and the internal space formed in the first spool. And a second internal passage that is formed in the second spool and that communicates the internal space with the tank.

In these inventions, when the pilot pressure is introduced into the internal pressure chamber, a part of the working fluid in the internal pressure chamber is discharged through the drain passage, but resistance is imparted by the throttle portion, so that a predetermined pressure is generated in the internal pressure chamber. .. Therefore, by supplying the pilot pressure to the internal pressure chamber, a thrust force for moving the first spool is generated in the internal pressure chamber, and the first spool can be moved.

Further, according to the present invention, the switching valve further includes a pair of first seating members that are seated at both ends of the first biasing member and move relative to each other as the first biasing member expands and contracts. The first biasing member further includes a pair of second seating members that are seated at both ends of the biasing member and that move relative to each other as the second biasing member expands and contracts, and the pair of first seating members abut each other. The movement of the first spool against the biasing force of the member is restricted, and the movement of the second spool against the biasing force of the second biasing member is restricted by the pair of second seating members contacting each other. Is characterized by.

According to the present invention, the movement amounts of the first spool and the second spool can be easily set.

Further, according to the present invention, the first spool is attached to the inner peripheral surface of the accommodation hole, the first main body portion is attached to the end portion of the first main body portion, and the first biasing member is provided on the outer periphery of the first support. A second main body part that is in contact with the inner peripheral surface of the housing hole, and a second biasing member is provided on the outer peripheral surface of the second main body part. A first supporting portion, the first main body portion axially protruding toward the first supporting portion, and the first supporting portion abuts against the first supporting portion; and the second main body portion includes the second supporting portion. It has a 2nd protrusion part which protrudes toward the part in the direction of an axis, and the 2nd support part contacts.

In the present invention, by changing the amount of protrusion of the first protrusion and the second protrusion, the first support part, the second support part, the first seating member, and the second seating member are commonly used, and The movement amount of the spool and the second spool can be changed.

Further, the present invention is characterized in that the accommodation hole is formed as a through hole having a uniform inner diameter.

In this invention, since the inner peripheral surface of the accommodation hole can be polished and finished, the processing accuracy of the accommodation hole is improved.

According to the present invention, the manufacturing cost of the fluid pressure control device is reduced.

It is a block diagram which shows a part of hydraulic excavator. It is a hydraulic circuit diagram showing a fluid pressure control device according to an embodiment of the present invention. It is an enlarged view which expanded a part of hydraulic circuit diagram showing the fluid pressure control device concerning the embodiment of the present invention. It is sectional drawing which shows the switching valve and bypass cut valve of the fluid pressure control apparatus which concerns on embodiment of this invention, and shows a state with a switching valve in a 1st switching position and a bypass cut valve in an open position. It is an expanded sectional view showing a switching valve of a fluid pressure control device concerning an embodiment of the present invention. It is sectional drawing which shows the switching valve and bypass cut valve of the fluid pressure control apparatus which concerns on embodiment of this invention, and shows the state which a switching valve is a 2nd switching position and a bypass cut valve is a blocking position. FIG. 3 is a cross-sectional view showing a switching valve and a bypass cut valve of the fluid pressure control device according to the embodiment of the present invention, showing a state in which the switching valve is switched to a second switching position by pilot pressure.

Hereinafter, a fluid pressure control device 100 according to an embodiment of the present invention will be described with reference to the drawings. In the following, a fluid pressure control device 100 provided in a fluid pressure control system 101 used for a construction machine, particularly a hydraulic excavator (see FIG. 1) and controlling the flow of a working fluid supplied to and discharged from a fluid pressure actuator will be described as an example. To do.

First, an overall configuration of a fluid pressure control system 101 including a fluid pressure control device 100 will be described with reference to FIG.

The fluid pressure control system 101 includes a first pump P1 and a second pump P2 that discharge hydraulic oil as a working fluid, a tank T that stores the hydraulic fluid, and a drive target such as a boom 102, an arm 103, or a bucket 104 ( 1), a first hydraulic cylinder (fluid pressure cylinder) 1 as a first actuator, and a second hydraulic cylinder (fluid pressure cylinder) 2 as a second actuator that drives a spare attachment (not shown). , A fluid pressure control device 100 for controlling the operation of the first hydraulic cylinder 1 and the second hydraulic cylinder 2. Hereinafter, the case where the first hydraulic cylinder 1 drives the boom 102 will be described as an example, and detailed description of the hydraulic cylinders that drive a drive target other than the boom 102 will be omitted.

The first pump P1 and the second pump P2 are driven by an engine (not shown) or a motor (not shown), respectively, and discharge hydraulic oil.

The first hydraulic cylinder 1 and the second hydraulic cylinder 2 have the same configuration as each other. Therefore, the configuration of the first hydraulic cylinder 1 will be specifically described below, and each configuration of the second hydraulic cylinder 2 will be denoted by the same reference numeral as that of the corresponding configuration of the first hydraulic cylinder 1 in the drawings. , And detailed description is omitted.

The first hydraulic cylinder 1 is a double-acting cylinder having a piston 4 that divides the inside of the cylinder tube 3 into a rod side chamber 6 and a bottom side chamber 7. A piston rod 5 is connected to the piston 4. Hydraulic oil is supplied to and discharged from the rod-side chamber 6 of the first hydraulic cylinder 1 through the first rod-side passage 8a. Hydraulic fluid is supplied to and discharged from the bottom side chamber 7 of the first hydraulic cylinder 1 through the first bottom side passage 9a. The working oil is supplied to and discharged from the rod side chamber 6 of the second hydraulic cylinder 2 through the second rod side passage 8b. The hydraulic oil is supplied to and discharged from the bottom side chamber 7 of the second hydraulic cylinder 2 through the second bottom side passage 9b.

By supplying hydraulic oil to the bottom side chamber 7 and discharging hydraulic oil from the rod side chamber 6, the first hydraulic cylinder 1 extends and the boom 102 is raised. On the contrary, when the hydraulic oil is supplied to the rod side chamber 6 and the hydraulic oil is discharged from the bottom side chamber 7, the first hydraulic cylinder 1 contracts to lower the boom 102. In the first hydraulic cylinder 1 that drives the boom 102, the bottom side chamber 7 is a load side pressure chamber under the weight of the boom 102, and the rod side chamber 6 is an anti-load side pressure chamber. Therefore, the first hydraulic cylinder 1 can communicate with the bottom side chamber 7, which is the load side pressure chamber, to the tank T, and can be contracted by the weight of the boom 102. The operation of the first hydraulic cylinder 1 and the second hydraulic cylinder 2 will be described later in detail.

Next, the fluid pressure control device 100 will be described.

The fluid pressure control device 100 controls the flow of hydraulic oil discharged from the first pump P1 and the second pump P2, and controls the expansion and contraction operations of the first hydraulic cylinder 1 and the second hydraulic cylinder 2. The first hydraulic cylinder 1 expands and contracts by being supplied with the hydraulic oil discharged from the first pump P1. The second hydraulic cylinder 2 expands and contracts when the hydraulic oil discharged from the first pump P1 or the second pump P2 is selectively supplied. The overall configuration of the fluid pressure control device 100 will be described below with reference to the hydraulic circuit diagram of FIG.

As shown in FIG. 2, the fluid pressure control device 100 includes a first pump passage 10 that guides working oil discharged from the first pump P1 and a second pump passage 11 that guides working oil discharged from the second pump P2. A main passage 12 into which the hydraulic oil discharged from the first pump P1 or the second pump P2 is selectively guided; and a flow of hydraulic oil supplied to and discharged from the first hydraulic cylinder 1 provided in the first pump passage 10. Control valve 20 for controlling the flow rate, a second control valve 30 provided in the main passage 12 for controlling the flow of hydraulic oil supplied to and discharged from the second hydraulic cylinder 2, and a first pump passage provided in the main passage 12 10 and the switching valve 40 that selectively switches a passage communicating with the main passage 12 of the second pump passage 11.

Each of the first control valve 20 and the second control valve 30 is a spool valve which has a spool (not shown) and whose position is switched as the spool moves.

The first control valve 20 has a pair of pilot chambers 21a and 21b and springs 22a and 22b as biasing members, and operates according to the pressure difference between the pair of pilot chambers 21a and 21b.

The first control valve 20 has a first pump passage 10, a first branch passage 13 branched from the first pump passage 10 upstream of the first control valve 20 (on the first pump P1 side), and a first communication passage with the tank T. The tank passage 16a is connected to the first rod-side passage 8a and the first bottom-side passage 9a, which are connected to the first hydraulic cylinder 1, respectively. The first branch passage 13 is provided with a first check valve 81 that allows the flow of hydraulic oil from the first pump P1 toward the first control valve 20 and restricts the flow thereof.

The first control valve 20 has a first neutral position 20</b>A that opens the first pump passage 10 and a first extended position that guides the hydraulic oil introduced from the first pump passage 10 to the first hydraulic cylinder 1 through the first branch passage 13. 20B and a first contracted position 20C.

When the pilot pressure is not guided to the pair of pilot chambers 21a and 21b of the first control valve 20, the first control valve 20 is held at the first neutral position 20A by the pair of springs 22a and 22b. At the first neutral position 20A, the first rod side passage 8a, the first bottom side passage 9a, the first branch passage 13 and the first tank passage 16a are blocked. Therefore, the first hydraulic cylinder 1 does not expand and contract, and is maintained in the load holding state.

When the pilot pressure is introduced into one pilot chamber 21a of the first control valve 20, the first control valve 20 switches to the first extension position 20B. At the first extension position 20B, the first branch passage 13 and the first bottom side passage 9a communicate with each other, and the first tank passage 16a and the first rod side passage 8a communicate with each other. Further, in the first extended position 20B, the first pump passage 10 is shut off. Therefore, when the first control valve 20 is switched to the first extended position 20B, the working oil discharged from the first pump P1 is supplied to the bottom side chamber 7, and the working oil in the rod side chamber 6 is discharged to the tank T. As a result, the first hydraulic cylinder 1 is extended.

When the pilot pressure is introduced to the other pilot chamber 21b of the first control valve 20, the first control valve 20 switches to the first contracted position 20C. At the first contracted position 20C, the first branch passage 13 and the first rod side passage 8a communicate with each other, and the first tank passage 16a and the first bottom side passage 9a communicate with each other. Further, in the first contracted position 20C, the first pump passage 10 is opened via the pump throttle 23 that imparts resistance to the flow of hydraulic oil passing therethrough. When the first control valve 20 is switched to the first contraction position 20C, the bottom side chamber 7 communicates with the tank T, so that the first hydraulic pressure is generated by the discharge pressure supplied from the first pump P1 to the rod side chamber 6 or the load of the boom 102. The cylinder 1 is contracted. The first contracted position 20C corresponds to the drive position.

Here, the first contracted position 20C of the first control valve 20 will be described more specifically with reference to FIG. In the following, in the first contraction position 20C, the flow passage that connects the first branch passage 13 and the first rod-side passage 8a is referred to as the "first communication passage 27", the first tank passage 16a and the first bottom-side passage 9a. A flow path communicating with each other is referred to as a "second communication passage 28". The first control valve 20 is provided with a rod-side throttle 24 and a bottom-side throttle 25 as throttles that add resistance to the flow of hydraulic oil passing therethrough. The rod-side throttle 24 is provided in the first communication passage 27. The bottom diaphragm 25 includes a first diaphragm 25a and a second diaphragm 25b that are provided in the second communication passage 28 in series with each other, and a third diaphragm 25c that is provided in parallel with the first diaphragm 25a and the second diaphragm 25b. Have.

The first communication passage 27 and the second communication passage 28 communicate with each other through the third communication passage 29. The third communication passage 29 communicates with the second communication passage 28 in the flow passage between the first throttle 25a and the second throttle 25b. The third communication passage 29 is provided with an internal check valve 85 that allows only the flow of hydraulic oil from the second communication passage 28 toward the first communication passage 27. The specific content of switching the first control valve 20 to the first contraction position 20C and contracting the first hydraulic cylinder 1 will be described later in detail.

The second control valve 30 includes a pair of pilot chambers 31a and 31b and springs 32a and 32b as biasing members, and operates according to the pressure difference between the pair of pilot chambers 31a and 31b. As shown in FIG. 2, the second control valve 30 is provided in the main passage 12 in which the hydraulic oil discharged from the first pump P1 or the second pump P2 is guided and communicates with the tank T. Further, in the second control valve 30, a main passage 12, a second branch passage 14 as a supply passage branched from the main passage 12 upstream of the second control valve 30, a second tank passage 16b communicating with the tank T, and The second rod side passage 8b and the second bottom side passage 9b, which are respectively connected to the second hydraulic cylinder 2, are connected.

The parallel passage 15 that branches from the first pump passage 10 joins the second branch passage 14 upstream of the first control valve 20. The parallel passage 15 guides the hydraulic fluid discharged from the first pump P1 to the second control valve 30. The second branch passage 14 is provided with a second check valve 82 that allows the flow of the hydraulic oil from the main passage 12 to the second control valve 30 and restricts the flow thereof. The second check valve 82 restricts the hydraulic oil guided through the parallel passage 15 from being guided into the main passage 12. Further, the parallel passage 15 is provided with a third check valve 83 that allows the flow of the hydraulic oil from the first pump passage 10 to the second branch passage 14 and regulates the opposite. In the parallel passage 15 on the upstream side (first pump P1 side) of the second check valve 82, a throttle 84 that imparts resistance to the flow of hydraulic oil passing therethrough is provided.

The second control valve 30 is a second neutral position 30A that opens the main passage 12, and a second position that is a supply position that supplies the hydraulic oil discharged from the first pump P1 or the second pump P2 to the second hydraulic cylinder 2. It has an extension position 30B and a second contraction position 30C.

When the pilot pressure is not guided to the pair of pilot chambers 31a and 31b of the second control valve 30, the second control valve 30 is held at the second neutral position 30A by the pair of springs 32a and 32b. At the second neutral position 30A, the second branch passage 14, the second rod side passage 8b, the second bottom side passage 9b, and the second tank passage 16b are blocked. Therefore, the second hydraulic cylinder 2 does not expand and contract, and is maintained in the load holding state.

When the pilot pressure is introduced into one pilot chamber 31a of the second control valve 30, the second control valve 30 switches to the second extension position 30B. At the second extension position 30B, the second branch passage 14 and the second bottom side passage 9b communicate with each other, and the second tank passage 16b and the second rod side passage 8b communicate with each other. Further, in the first extended position 20B, the main passage 12 is shut off. Therefore, when the second control valve 30 is switched to the second extended position 30B, the hydraulic oil discharged from the first pump P1 or the second pump P2 is supplied to the bottom side chamber 7 through the second branch passage 14, and the rod side chamber 6 Of the hydraulic oil is discharged to the tank T. As a result, the second hydraulic cylinder 2 is extended.

When the pilot pressure is introduced into the other pilot chamber 31b of the second control valve 30, the second control valve 30 switches to the second contraction position 30C. At the second contracted position 30C, the second branch passage 14 and the second rod side passage 8b communicate with each other, and the second tank passage 16b and the second bottom side passage 9b communicate with each other. Further, at the second extended position 30B, the main passage 12 is blocked. Therefore, when the second control valve 30 is switched to the second contraction position 30C, the working oil discharged from the first pump P1 or the second pump P2 is supplied to the rod side chamber 6 through the second branch passage 14, and the bottom side chamber 7 Of the hydraulic oil is discharged to the tank T. As a result, the second hydraulic cylinder 2 is contracted.

The switching valve 40 is a two-position spool valve that has a spool (see FIG. 4) and that switches its position as the spool moves. Hereinafter, the spool of the switching valve 40 will be referred to as the “first spool 41”.

The switching valve 40 includes a first pump passage 10 that guides hydraulic fluid discharged from the first pump P1, a second pump passage 11 that guides hydraulic fluid discharged from the second pump P2, and a second control valve 30 (second hydraulic pressure). It is connected to the main passage 12 that guides the hydraulic oil to the cylinder 2), and the third tank passage 16c and the fourth tank passage 16d that communicate with the tank T, respectively.

The switching valve 40 communicates the first pump passage 10 and the main passage 12 with each other, and communicates the second pump passage 11 with the third tank passage 16c with the first switching position 40A, the second pump passage 11 and the main passage 12. And a second switching position 40B that connects the first pump passage 10 and the fourth tank passage 16d. When the switching valve 40 is switched to the first switching position 40A, the hydraulic oil discharged from the first pump P1 is guided to the second control valve 30 through the main passage 12. When the switching valve 40 is switched to the second switching position 40B, the hydraulic oil discharged from the second pump P2 is guided to the second control valve 30 through the main passage 12. Therefore, by switching the position of the switching valve 40, it is possible to select whether to guide the hydraulic oil from the first pump P1 to the second control valve 30 or the hydraulic oil from the second pump P2 to the second control valve 30. You can

The switching valve 40 has a first spring 51 as a first biasing member that biases the first spool 41 so as to be in the first switching position 40A, and a biasing force of the first spring 51 that is manually operated by an operator. And a switching unit 55 that moves the first spool 41 to switch to the second switching position 40B. The specific configuration and operation of the switching valve 40 will be described in detail later.

The fluid pressure control device 100 includes a bypass cut valve 60 provided in the first pump passage 10 downstream of the first control valve 20 and upstream of the switching valve 40 (between the first control valve 20 and the switching valve 40). Further prepare.

The bypass cut valve 60 is a two-position spool valve that has a spool (see FIG. 4) and is switched between positions as the spool moves. Hereinafter, the spool of the bypass cut valve 60 will be referred to as a "second spool 61".

The bypass cut valve 60 has an open position 60A that opens the first pump passage 10 and a shut-off position 60B that shuts off the first pump passage 10. The bypass cut valve 60 moves the second spool 61 against the urging force of the second spring 71 as a second urging member that urges the second spool 61 to the open position 60A. A pilot chamber 78 to which a biasing pilot pressure is introduced. The specific configuration and operation of the bypass cut valve 60 will be described later in detail.

Next, the operation of the fluid pressure control device 100 will be described.

In the fluid pressure control device 100, by switching the position of the switching valve 40, the second hydraulic cylinder 2 is also driven by the first pump P1 that supplies the hydraulic oil to the first hydraulic cylinder 1, or the first pump P1 is used to drive the first hydraulic cylinder 1. It is switched whether the hydraulic cylinder 1 is driven and the second hydraulic cylinder 2 is driven by the second pump P2. Hereinafter, the case where the switching valve 40 is in the first switching position 40A and the case where the switching valve 40 is in the second switching position 40B will be described respectively.

[First switching position 40A]
First, the case where the switching valve 40 is switched to the first switching position 40A will be described. When the switching valve 40 is in the first switching position 40A, the first pump passage 10 and the main passage 12 communicate with each other, and the hydraulic fluid discharged from the first pump P1 is guided to the second control valve 30.

[Independent drive of the first hydraulic cylinder 1]
When the first hydraulic cylinder 1 is driven independently without driving the second hydraulic cylinder 2, the second control valve 30 is switched to the second neutral position 30A by the pair of springs 32a and 32b. Further, the bypass cut valve 60 is switched to the open position 60A.

When the first hydraulic cylinder 1 is extended, the pilot pressure is introduced into the one pilot chamber 21a of the first control valve 20 according to the operation of the operation lever (not shown) by the operator. As a result, the first control valve 20 is switched to the first extension position 20B.

When the first control valve 20 is switched to the first extended position 20B, the hydraulic oil discharged from the first pump P1 is first passed through the first pump passage 10, the first branch passage 13 and the first bottom passage 9a. It is guided to the bottom side chamber 7 of the hydraulic cylinder 1. Further, the hydraulic oil in the rod side chamber 6 of the first hydraulic cylinder 1 is discharged to the tank T from the first rod side passage 8a through the first tank passage 16a. As a result, the first hydraulic cylinder 1 extends.

When the first hydraulic cylinder 1 is contracted, the pilot pressure is introduced into the other pilot chamber 21b of the first control valve 20 according to the operation of the operation lever by the operator. As a result, the first control valve 20 is switched to the first contracted position 20C.

When the first control valve 20 is switched to the first contraction position 20C, the first branch passage 13 and the first rod-side passage 8a communicate with each other, and the first pump passage 10 is opened via the pump throttle 23. When the first hydraulic cylinder 1 is independently contracted, the second passage 30 opens the main passage 12 to communicate with the tank T. Therefore, the first pump passage 10 communicates with the tank T through the main passage 12, and the discharge pressure of the first pump P1 is not guided to the rod side chamber 6. On the other hand, in the first hydraulic cylinder 1 that drives the boom 102, the weight of the boom 102 acts on the bottom side chamber 7. Therefore, in this case, the bottom side chamber 7 is contracted by the load of the boom 102 instead of the discharge pressure of the first pump P1, and the hydraulic oil in the bottom side chamber 7 is transferred to the tank through the first bottom side passage 9a and the first tank passage 16a. It is discharged to T. Further, hydraulic oil is supplied to the rod side chamber 6 through the first branch passage 13 as the volume is expanded. In this way, the first hydraulic cylinder 1 contracts under the load of the boom 102.

The hydraulic oil discharged from the bottom side chamber 7 when the first hydraulic cylinder 1 contracts includes the first throttle 25a, the second throttle 25b, and the third throttle 25c provided in the second communication passage 28 of the first control valve 20. Through the tank T (see FIG. 3). Therefore, the first hydraulic cylinder 1 contracts at a speed according to the resistance imparted by the first diaphragm 25a, the second diaphragm 25b, and the third diaphragm 25c. Therefore, by adjusting the resistances given by the first diaphragm 25a, the second diaphragm 25b, and the third diaphragm 25c, the speed of the contraction operation of the first hydraulic cylinder 1 can be adjusted.

Further, by adjusting the resistances given by the first throttle 25a, the second throttle 25b, and the third throttle 25c, the hydraulic oil discharged from the bottom side chamber 7 is passed through the second communication passage 28 and the third communication passage 29 to the It is also possible to regenerate the first communication passage 27. Specifically, by adjusting the flow path resistance (opening) of the first throttle 25a and the third throttle 25c, the working oil discharged from the bottom side chamber 7 of the first hydraulic cylinder 1 is discharged to the tank T. It is possible to adjust the ratio of the flow rate of the operating oil (bleed flow rate) to the flow rate regenerated to the first communication passage 27 (regeneration flow rate). When the opening of the first throttle 25a is larger than the opening of the third throttle 25c, the ratio of the regeneration flow rate increases according to the difference in the opening. On the contrary, when the opening of the first throttle 25a is smaller than the opening of the third throttle 25c, the ratio of the bleed flow rate increases according to the difference in the opening. As described above, the regeneration flow rate and the bleed flow rate can be adjusted by mainly adjusting the opening degrees of the first diaphragm 25a and the third diaphragm 25c.

[Independent drive of the second hydraulic cylinder 2]
When the switching valve 40 is in the first switching position 40A and the first hydraulic cylinder 1 is not driven but the second hydraulic cylinder 2 is driven independently, the first control valve 20 includes the pair of springs 22a and 22b. Is switched to the first neutral position 20A. Further, the bypass cut valve 60 is switched to the open position 60A. The working oil discharged from the first pump P1 is guided to the main passage 12 through the first pump passage 10 and the parallel passage 15.

When the second hydraulic cylinder 2 is extended, the pilot pressure is introduced into the one pilot chamber 31a of the second control valve 30 according to the operation of the operation lever by the operator. As a result, the second control valve 30 is switched to the second extension position 30B.

When the second control valve 30 is switched to the second extended position 30B, the working oil discharged from the first pump P1 guided to the main passage 12 is supplied to the bottom side chamber 7 of the second hydraulic cylinder 2 through the second bottom side passage 9b. Be led to. Further, the hydraulic oil in the rod side chamber 6 of the second hydraulic cylinder 2 is discharged to the tank T from the second rod side passage 8b through the second tank passage 16b. As a result, the second hydraulic cylinder 2 is extended.

When the second hydraulic cylinder 2 is contracted, the pilot pressure is introduced into the other pilot chamber 31b of the second control valve 30 according to the operation of the operation lever by the operator. As a result, the second control valve 30 is switched to the second contraction position 30C.

When the second control valve 30 is switched to the second contraction position 30C, the hydraulic oil discharged from the first pump P1 guided through the main passage 12 is discharged through the second rod side passage 8b into the rod side chamber 6 of the second hydraulic cylinder 2. Be led to. Further, the hydraulic oil in the bottom side chamber 7 of the second hydraulic cylinder 2 is discharged to the tank T from the second bottom side passage 9b through the second tank passage 16b. This causes the second hydraulic cylinder 2 to contract.

[Composite operation]
Next, a combined operation of expanding and contracting the first hydraulic cylinder 1 and expanding and contracting the second hydraulic cylinder 2 will be described. In the following, as a combined operation, the first control valve 20 is switched to the first extension position 20B to extend the first hydraulic cylinder 1, and the second control valve 30 is switched to the second extension position 30B to move to the second hydraulic cylinder. The case where the extension operation of 2 is performed will be described.

The case of extending the first hydraulic cylinder 1 in the combined operation is basically the same as the case of extending the first hydraulic cylinder 1 alone, and thus detailed description thereof will be omitted.

When the first control valve 20 switches to the first extended position 20B, the first pump passage 10 is shut off. Therefore, the working oil discharged from the first pump P1 is not guided to the second branch passage 14 through the first pump passage 10 and the main passage 12. On the other hand, the hydraulic oil discharged from the first pump P1 is guided to the second branch passage 14 through the parallel passage 15. Therefore, the bottom side chamber 7 of the second hydraulic cylinder 2 is supplied with the working oil guided from the parallel passage 15 to the second bottom side passage 9b through the second branch passage 14, and the second hydraulic cylinder 2 is extended.

As described above, in the combined operation when the switching valve 40 is in the first switching position 40A, part of the hydraulic oil discharged from the first pump P1 is guided to the first hydraulic cylinder 1 through the first pump passage 10, and The remaining hydraulic oil discharged from the first pump P1 is guided to the second hydraulic cylinder 2 through the parallel passage 15.

In the combined operation, the second control valve 30 is switched to the second extension position 30B or the second contraction position 30C. Therefore, in the combined operation, when the first hydraulic cylinder 1 is contracted, if the first control valve 20 is switched to the first contraction position 20C, the main passage 12 communicates with the tank T by the second control valve 30. Is cut off. Therefore, when the first hydraulic cylinder 1 is contracted in the combined operation, the discharge pressure of the first pump P1 is guided to the rod side chamber 6, and the first hydraulic cylinder 1 is driven by the discharge pressure of the first pump P1. It contracts.

[Jack up]
As described above, when the bypass cut valve 60 is in the open position 60A, the second control valve 30 is in the second neutral position 30A, and the first control valve 20 is in the first contracted position 20C, the first pump passage 10 communicates with the tank T. Then, the first hydraulic cylinder 1 contracts due to the load (self-weight) of the boom 102. The contraction operation of the first hydraulic cylinder 1 by the load of the boom 102 is performed while the bucket 104 is not grounded.

On the other hand, in the hydraulic excavator, the jack-up operation of lifting the vehicle body of the hydraulic excavator is performed by contracting the first hydraulic cylinder 1 (lowering the boom 102) while the bucket 104 is grounded. In the jack-up operation, the discharge pressure of the first pump P1 is guided to the rod side chamber 6 of the first hydraulic cylinder 1 to cause the first hydraulic cylinder 1 to contract.

When performing the jack-up operation, the pilot pressure is introduced into the pilot chamber 78 of the bypass cut valve 60 by the operation of the operation lever by the operator. As a result, the bypass cut valve 60 is switched to the shutoff position 60B, and the first pump passage 10 is shut off. Therefore, even if the first control valve 20 is switched to the first contraction position 20C in the state where the bypass cut valve 60 is in the shutoff position 60B, the first pump passage 10 does not communicate with the tank T. Therefore, the discharge pressure of the first pump P1 is guided to the rod side chamber 6 of the first hydraulic cylinder 1 through the first branch passage 13 and the first rod side passage 8a. As a result, the first hydraulic cylinder 1 contracts due to the discharge pressure of the first pump P1, and thus exerts thrust for lifting the vehicle body of the hydraulic excavator. In this way, the jack-up operation is performed.

[Second switching position 40B]
Next, a case will be described in which the switching valve 40 is switched to the second switching position 40B and the hydraulic oil discharged from the second pump P2 is guided to the second control valve 30. When the switching valve 40 is switched to the second switching position 40B, the second pump passage 11 and the main passage 12 communicate with each other, and the first pump passage 10 communicates with the tank T through the fourth tank passage 16d. Even when the switching valve 40 is in the first switching position 40A and the second control valve 30 is in the second neutral position 30A, the first pump passage 10 communicates with the tank T. Therefore, the single drive of the first hydraulic cylinder 1 when the switching valve 40 is at the second switching position 40B is the same as when the switching valve 40 is at the first switching position 40A. The jack-up operation is the same regardless of the position of the switching valve 40. Therefore, the independent drive and the combined operation of the second hydraulic cylinder 2 will be described below.

[Independent drive of the second hydraulic cylinder 2]
When the switching valve 40 is in the second switching position 40B, the hydraulic oil discharged from the second pump P2 is guided to the second branch passage 14 through the main passage 12. When the switching valve 40 is in the second switching position 40B, the first pump passage 10 communicates with the tank T, so the parallel passage 15 also communicates with the tank T. Therefore, the working oil discharged from the first pump P1 is not guided to the second branch passage 14, but only the working oil discharged from the second pump P2 is guided to the second branch passage 14.

Therefore, by switching the second control valve 30, the hydraulic oil discharged from the second pump P2 is guided to the second hydraulic cylinder 2 through the second branch passage 14. Thus, when the switching valve 40 is in the second switching position 40B, the second hydraulic cylinder 2 is driven by the hydraulic oil discharged from the second pump P2.

[Composite operation]
When the switching valve 40 is in the second switching position 40B, when the first control valve 20 is switched to the first contraction position 20C, the first pump passage 10 communicates with the tank T through the pump throttle 23. Therefore, the hydraulic oil discharged from the first pump P1 is not guided to the parallel passage 15, and only the hydraulic oil discharged from the second pump P2 is guided to the second branch passage 14.

Further, when the switching valve 40 is in the second switching position 40B, when the first control valve 20 is switched to the first extension position 20B, the first pump passage 10 is shut off. Therefore, the hydraulic oil discharged from the first pump P1 is guided to the parallel passage 15. Here, since the parallel passage 15 is provided with the throttle 84 and the third check valve 83, a pressure loss occurs in the flow of the hydraulic oil guided to the parallel passage 15 due to the throttle 84. Further, since a part of the hydraulic oil discharged from the first pump P1 is guided to the first hydraulic cylinder 1, the flow rate of the hydraulic oil guided to the parallel passage 15 is reduced and the pressure is reduced accordingly. Therefore, the discharge pressure of the second pump P2 guided to the second branch passage 14 becomes higher than the discharge pressure of the first pump P1 guided to the parallel passage 15. Therefore, the third check valve 83 does not open, and the hydraulic oil passing through the parallel passage 15 is restricted from being guided to the second branch passage 14. That is, since the third check valve 83 does not open, only the hydraulic oil discharged from the second pump P2 is guided to the second branch passage 14.

In this way, also in the combined operation when the switching valve 40 is in the second switching position 40B, the second hydraulic cylinder 2 is discharged from the second pump P2, as in the case of independently driving the second hydraulic cylinder 2. Driven by hydraulic oil

As described above, when the switching valve 40 is in the first switching position 40A, the hydraulic oil discharged from the first pump P1 is used both when the second hydraulic cylinder 2 is driven independently and when it is operated in combination. The second hydraulic cylinder 2 is driven by. When the switching valve 40 is in the second switching position 40B, the second hydraulic cylinder is driven by the hydraulic oil discharged from the second pump P2 regardless of whether the second hydraulic cylinder 2 is independently driven or operates in combination. 2 drives.

Here, the auxiliary attachment driven by the second hydraulic cylinder 2 differs depending on the type of hydraulic excavator on which the fluid pressure control device 100 is mounted. When a large thrust is required to drive the auxiliary attachment, the second hydraulic cylinder 2 needs to be large. When guiding the hydraulic oil of the first pump P1 to both the first hydraulic cylinder 1 and the second hydraulic cylinder 2, the hydraulic oil supplied to the other by the operation of one of the first hydraulic cylinder 1 and the second hydraulic cylinder 2. Flow rate fluctuates. Therefore, when the second hydraulic cylinder 2 is relatively large, the flow rate of the hydraulic oil supplied to the second hydraulic cylinder 2 increases correspondingly, and the first hydraulic cylinder 1 and the second hydraulic cylinder 2 during the combined operation. The operation of the cylinder 2 may become unstable.

On the contrary, there are cases where the second hydraulic cylinder 2 is small, and fluctuations in the flow rate of the hydraulic oil supplied to the first hydraulic cylinder 1 and the second hydraulic cylinder 2 during the combined operation are allowed. In this case, both the first hydraulic cylinder 1 and the second hydraulic cylinder 2 are driven by the hydraulic oil of the first pump P1 so that the second pump P2 is not provided or the second pump P2 is not provided. Can be used to drive other hydraulic cylinders, which is advantageous in terms of cost and efficiency.

In the fluid pressure control device 100, by switching the position of the switching valve 40 by a manual operation, hydraulic fluid is introduced from the first pump P1 to the second hydraulic cylinder 2 depending on the type of hydraulic excavator and the needs of the user, or It is possible to select whether to guide the hydraulic oil from the second pump P2 to the second hydraulic cylinder 2. Since the pump that supplies the hydraulic oil to the second hydraulic cylinder 2 can be selected by switching the switching valve 40, regardless of which pump the user drives the second hydraulic cylinder 2, the piping of the fluid pressure control device 100 can be selected. The structure can be common. Therefore, the manufacturing cost of the fluid pressure control device 100 can be reduced.

In other words, by manually switching the position of the switching valve 40, the same fluid pressure control device 100 can be used for different hydraulic excavators and user needs, and the manufacturing cost is reduced.

Further, in the fluid pressure control device 100, the bypass passage 15 branching from the first main passage 10 is connected to the second branch passage 14. The second branch passage 14 does not communicate with the tank T regardless of the position of the second control valve 30. Further, when the switching valve 40 is switched to the second switching position 40B, the discharge pressure of the second pump P2 closes the third check valve 83, so that the discharge pressure of the first pump P1 is guided to the second control valve. Not be Therefore, when the first hydraulic cylinder 1 is extended when the switching valve 40 is in the second switching position 40B, regardless of the position of the second control valve 30, the hydraulic oil discharged from the first pump P1 is It is not guided to the tank T or other equipment through the bypass passage 15. As described above, in the fluid pressure control device 100, when the switching valve 40 is set to the second switching position 40B and the first hydraulic cylinder 1 and the second hydraulic cylinder 2 are made independent, the hydraulic oil discharged from the first pump P1. Can be extended to the first hydraulic cylinder 1 to extend the first hydraulic cylinder 1. That is, in the fluid pressure control device 100, even when the switching valve 40 is switched to the second switching position 40B, the hydraulic oil discharged from the first pump P1 can be effectively used. In the present embodiment, even if the switching valve 40 is in the first switching position 40A, the communication between the bypass passage 15 and the tank T is blocked, or the hydraulic oil is guided to the second hydraulic cylinder 2 through the bypass passage 15. Either, Therefore, even when the switching valve 40 is in the first switching position 40A, the hydraulic oil discharged from the first pump P1 can be effectively used.

Next, specific configurations of the switching valve 40 and the bypass cut valve 60 will be described with reference to FIGS. 4 and 5.

As shown in FIG. 4, the fluid pressure control device 100 includes a housing 90 that accommodates the switching valve 40 and the bypass cut valve 60. The housing 90 is formed with a housing hole 91 which is a through hole whose both ends open to the end surfaces 90a and 90b of the housing 90. The accommodation hole 91 is formed as a through hole having a uniform inner diameter.

Further, the housing 90 is formed with a first pump passage 10, a second pump passage 11, a main passage 12, a third tank passage 16c, and a fourth tank passage 16d, each of which has an annular shape on the inner peripheral surface of the accommodation hole 91. Open through the port (not shown). Further, the housing 90 is formed with an annular drain port 18 a communicating with the tank T and opening at the inner peripheral surface of the accommodation hole 91. Hereinafter, the first pump passage 10 on the upstream side of the bypass cut valve 60 will be referred to as an “upstream passage 10a”, and the first pump passage 10 on the downstream side will also be referred to as a “downstream passage 10b”.

The switching valve 40 has a first spool 41 that is slidably inserted into the accommodation hole 91. The bypass cut valve 60 has a second spool 61 that is slidably inserted into the accommodation hole 91. The first spool 41 of the switching valve 40 and the second spool 61 of the bypass cut valve 60 are coaxially housed in the housing hole 91 so as to face each other.

The switching valve 40 is attached to the end surface 90 a of the housing 90 and seals one opening of the housing hole 91, and the first spool 41 provided in the first cap 50 separates the first spool 41 from the second spool 61. The first spring 51 that urges in the direction (leftward in the drawing), and the pair of first springs serving as the pair of first seating members in which both ends of the first spring 51 are seated and relatively move as the first spring 51 expands and contracts. The seats 52 and 53, a switching portion 55 that is attached to the first cap 50 and moves the first spool 41 against the biasing force of the first spring 51 by manual operation, and an internal pressure formed inside the first cap 50. It has a chamber 58 and an introduction port 50c formed in the first cap 50 to guide the pilot pressure to the internal pressure chamber 58.

The first spool 41 has a first main body portion 42 that is in sliding contact with the inner peripheral surface of the accommodation hole 91, and a first support portion 46 that is attached to one end (the left end in the drawing) of the first main body portion 42.

The first main body portion 42 has a first land portion 42a, a second land portion 42b, and a third land portion 42c that are in sliding contact with the inner peripheral surface of the accommodation hole 91 and are arranged in the axial direction. A first annular groove 43a is formed on the outer peripheral surface between the first land portion 42a and the second land portion 42b, and a first annular groove 43a is formed on the outer peripheral surface between the second land portion 42b and the third land portion 42c. Two annular grooves 43b are formed.

A first small diameter portion 44 having an outer diameter smaller than the inner diameter of the accommodation hole 91 is provided at one end of the first main body portion 42, and one end side of the first small diameter portion 44 (first support portion 46 side, left side in the drawing). The second small diameter portion 45 having an outer diameter smaller than that of the first small diameter portion 44 is formed. An annular space 43c is formed between the first small diameter portion 44 and the accommodation hole 91. The second small diameter portion 45 corresponds to a first protruding portion that axially protrudes from the first small diameter portion 44 toward the first support portion 46 and that the first support portion 46 contacts.

As shown in FIG. 5, the first support portion 46 is housed inside the first cap 50. The first support portion 46 has a first shaft portion 47 having a screw portion 47 a screwed to the second small diameter portion 45 at one end of the first body portion 42, and a first shaft portion 47 having an outer diameter larger than that of the first shaft portion 47. And a head portion 48. The first support portion 46 is detachably attached to the first main body portion 42 by screwing the screw portion 47 a of the first shaft portion 47.

The first shaft portion 47 has substantially the same outer diameter as the second small diameter portion 45 of the first body portion 42, and is coaxially attached to the second small diameter portion 45. A slit 48a extending in the radial direction is formed on the end surface of the first head portion 48.

The first cap 50 has a first large diameter hole 50a communicating with the accommodation hole 91 and into which the first spool 41 can enter, and a first large diameter hole 50a communicating with the first large diameter hole 50a and having an inner diameter smaller than that of the first large diameter hole 50a. The first small diameter hole 50b and the introduction port 50c communicating with the first large diameter hole 50a are formed. An internal pressure chamber 58 is formed by the first small diameter hole 50b and the first large diameter hole 50a. The first head portion 48 of the first support portion 46 enters the first small diameter hole 50b.

The first spring 51 is provided on the outer periphery of the first shaft portion 47 of the first support portion 46, and both ends thereof are supported by the pair of first spring seats 52 and 53. One first spring seat 52 is seated on the step surface 50d between the first large diameter hole 50a and the first small diameter hole 50b, and the other first spring seat is mounted on the end surface 90a of the housing 90 to which the first cap 50 is attached. 53 sits down. With the expansion and contraction of the first spring 51 (movement of the first spool 41), the one first spring seat 52 moves relative to the other first spring seat 53 along the axial direction of the first spool 41. The first spring 51 is interposed between the pair of first spring seats 52 and 53 in a compressed state. The first spring 51 exerts an urging force that moves the first spool 41 so that the switching valve 40 is in the first switching position 40A (in other words, it is separated from the second spool 61 of the bypass cut valve 60).

The pair of first spring seats 52, 53 are formed in the same shape. As shown in FIG. 5, one of the first spring seats 52 has a disc-shaped flange portion 52a that contacts a step surface 50d between the first large diameter hole 50a and the first small diameter hole 50b of the first cap 50. And a cylindrical boss portion 52b extending in the axial direction from the flange portion 52a toward the other first spring seat 53. One end of the first spring 51 is seated on the flange portion 52a. The boss portion 52b is inserted into the first spring 51 and supports the inner circumference of the first spring 51. The inner diameter of the flange portion 52a is smaller than the outer diameter of the first head portion 48. A slit 52c extending in the radial direction is formed on the end surface of the flange portion 52a that contacts the step surface 50d between the first large diameter hole 50a and the first small diameter hole 50b.

The other first spring seat 53 has a disc-shaped flange portion 53a that contacts the end surface 90a of the housing 90, and a cylindrical boss portion 53b that extends from the flange portion 53a toward the one first spring seat 52 in the axial direction. And have. The other end of the first spring 51 is seated on the flange portion 53a. The boss portion 53b is inserted into the first spring 51 and supports the inner circumference of the first spring 51. A slit 53c extending in the radial direction is formed on the end surface of the flange portion 53a that contacts the end surface 90a of the housing 90.

The switching portion 55 is screwed into a screw hole 50e formed in the first cap 50 and is moved forward and backward with respect to the first spool 41 by a manual operation, and a screwing position of the switching bolt 56 with respect to the screw hole 50e. A restriction nut 57 for restricting the change. The screw hole 50e is formed in the first cap 50 so as to communicate with the internal pressure chamber 58 (first small diameter hole 50b).

The switching bolt 56 is provided coaxially with the first support portion 46 of the first spool 41. The switching bolt 56 is operated by an operator, and a screwing portion 56a in which a male screw that is screwed into the screw hole 50e is formed, a contact portion 56b that comes into axial contact with the first head portion 48 of the first spool 41, and an operator. And an operation unit 56c. The contact portion 56b is housed in the first small diameter hole 50b. A part of the screwing portion 56a projects to the outside of the first cap 50, and an operating portion 56c is provided at the end of the projecting screwing portion 56a. When the operator grips and rotates the operation portion 56c, the screwing position of the screwing portion 56a with respect to the screw hole 50e is adjusted.

The restriction nut 57 is screwed into the screwing portion 56a exposed to the outside of the first cap 50. The restriction nut 57 screwed to the switching bolt 56 is tightened to the first cap 50, so that the change of the screwing position of the switching bolt 56 with respect to the screw hole 50e of the first cap 50 is restricted. On the contrary, by loosening the regulation nut 57 and creating a gap between the regulation nut 57 and the first cap 50, the screwing position of the switching bolt 56 with respect to the screw hole 50e of the first cap 50 can be adjusted, The switching bolt 56 can move forward and backward with respect to the first spool 41.

As shown in FIG. 4, the bypass cut valve 60 is attached to the end surface 90 b of the housing 90 and seals the other opening of the housing hole 91, and a second spool 61 provided in the second cap 70. Spring 71 for urging the second spring 71 away from the first spool 41 (to the right in the figure), and a pair of second seats in which both ends of the second spring 71 are seated and relatively move as the second spring 71 expands and contracts. It has a pair of second spring seats 72, 73 as members and a pilot chamber 78 formed inside the second cap 70.

The second spool 61 has a second main body portion 62 that is in sliding contact with the inner peripheral surface of the accommodation hole 91, and a second support portion 66 that is attached to one end (the right end in the figure) of the second main body portion 62.

The second main body portion 62 has a fourth land portion 62a, a fifth land portion 62b, a sixth land portion 62c, and a seventh land portion 62d which are in sliding contact with the inner peripheral surface of the accommodation hole 91 and are arranged in the axial direction. A third annular groove 63a is formed on the outer peripheral surface between the fourth land portion 62a and the fifth land portion 62b. A fourth annular groove 63b is formed on the outer peripheral surface between the fifth land portion 62b and the sixth land portion 62c. A fifth annular groove 63c is formed on the outer peripheral surface between the sixth land portion 62c and the seventh land portion 62d. The fifth annular groove 63c always communicates with the drain port 18a regardless of the position of the second spool 61.

A third small diameter portion 64 having an outer diameter smaller than the inner diameter of the accommodation hole 91 and protruding in the axial direction from the second body portion 62 is formed at one end of the second body portion 62. The third small diameter portion 64 corresponds to a second protruding portion that axially protrudes from the second main body portion 62 toward the second support portion 66 and is in contact with the second support portion 66.

The second support portion 66 is housed inside the second cap 70. The second support portion 66 includes a second shaft portion 67 having a screw portion 67a screwed to one end portion of the second body portion 62 of the second spool 61, and a second shaft portion 67 having a larger outer diameter than the second shaft portion 67. And a head portion 68. The second support portion 66 is detachably attached to the second main body portion 62 by screwing the screw portion 67 a of the second shaft portion 67.

The second shaft portion 67 has an outer diameter substantially the same as that of the third small diameter portion 64 of the second body portion 62, and is coaxially attached to the third small diameter portion 64.

The second cap 70 has a second large diameter hole 70a that communicates with the accommodation hole 91 and allows the second spool 61 to enter, and a second large diameter hole 70a that communicates with the second large diameter hole 70a and has an inner diameter smaller than that of the second large diameter hole 70a. The second small diameter hole 70b and the pilot port 70c communicating with the second small diameter hole 70b are formed. A pilot chamber 78 is formed by the second small diameter hole 70b and the second large diameter hole 70a. The second head portion 68 of the second support portion 66 enters the second small diameter hole 70b.

The second spring 71 is provided on the outer periphery of the second shaft portion 67 of the second support portion 66, and both ends thereof are supported by the pair of second spring seats 72 and 73. One second spring seat 72 is seated on the step surface 70d between the second large diameter hole 70a and the second small diameter hole 70b of the second cap 70, and the other second spring seat is attached to the other end surface 90b of the housing 90. 73 sits down. The second spring 71 is interposed between the pair of second spring seats 72 and 73 in a compressed state. The second spring 71 exerts an urging force that moves the second spool 61 so that the bypass cut valve 60 is in the open position 60A (in other words, it is separated from the first spool 41 of the switching valve 40).

The pair of second spring seats 72, 73 are formed in the same shape as each other. One of the second spring seats 72 is a disk-shaped flange portion 72a that contacts a step surface 70d between the second large diameter hole 70a and the second small diameter hole 70b of the second cap 70, and the other from the flange portion 72a. And a cylindrical boss portion 72b extending in the axial direction toward the second spring seat 73. The inner diameter of the flange portion 72a is smaller than the outer diameter of the second head portion 68.

The other second spring seat 73 has a disc-shaped flange portion 73a that contacts the end surface 90b of the housing 90, and a cylindrical boss portion 73b that axially extends from the flange portion 73a toward the one second spring seat 72. And have. Both ends of the second spring 71 are seated on the flange portions 72a and 73a of the second spring seats 72 and 73, respectively, and the boss portions 72b and 73b are inserted into the second spring 71 and support the inner circumference of the second spring 71, respectively. To do.

The first spool 41 and the second spool 61 are separated from each other in the axial direction so as not to contact each other regardless of the positions of the switching valve 40 and the bypass cut valve 60. An internal space 92 is formed in the accommodation hole 91 by the end portion of the first spool 41 and the end portion of the second spool 61.

The internal pressure chamber 58 inside the first cap 50 is in constant communication with the tank T through the drain passage 18. In the drain passage 18, a slit 53c (see FIG. 5) in the first spring seat 53, an annular space 43c on the outer periphery of the first small diameter portion 44 of the first spool 41, and a first main body portion 42 of the first spool 41 are formed. The first internal passage 49, the internal space 92 between the first spool 41 and the second spool 61, the second internal passage 69 formed in the second main body portion 62 of the second spool 61, and the housing 90. A drain port 18a is included.

The first internal passage 49 passes through the axial center of the first main body portion 42, opens at the end surface of the first spool 41 facing the second spool 61, and communicates with the internal space 92. A throttle passage 49b communicating with the one-axis direction passage 49a and opening to the annular space 43c on the outer periphery of the first small diameter portion 44 is formed.

The second internal passage 69 passes through the axis of the second main body portion 62, opens at the end surface of the second spool 61 facing the first spool 41, and communicates with the internal space 92. And a radial passage 69b communicating with the biaxial passage 69a and opening to the fifth annular groove 63c. The fifth annular groove 63c always communicates with the drain port 18a regardless of the position of the second spool 61, so that the internal pressure chamber 58 in the first cap 50 always communicates with the tank T through the drain passage 18. Since the internal pressure chamber 58 in the first cap 50 always communicates with the tank T, the malfunction of the first spool 41 moving due to the pressure buildup in the first cap 50 is prevented.

The throttle passage 49b formed in the first main body portion 42 is a throttle portion that imparts resistance to the flow of hydraulic oil passing therethrough. The throttle passage 49b is a passage having the largest resistance applied to the flow of the hydraulic oil in the hydraulic oil passage from the internal pressure chamber 58 to the drain port 18a. The throttle portion may be configured by an orifice plug or the like that is detachably attached to the drain passage 18.

Next, the operation of the switching valve 40 and the bypass cut valve 60 will be described with reference to FIGS.

When the switching valve 40 is manually switched from the first switching position 40A (the state shown in FIG. 4) to the second switching position 40B (the state shown in FIG. 6), the regulating nut 57 is loosened and directed toward the first spool 41. The switching bolt 56 is rotated so as to move. As a result, the first spool 41 is pressed by the switching bolt 56 and moves against the biasing force of the first spring 51. Further, with the movement of the first spool 41 against the urging force of the first spring 51, the one first spring seat 52 is also pushed toward the other first spring seat 53 by being pressed by the first head portion 48. ..

The first spool 41 moves against the biasing force of the first spring 51 until the boss portions 52b, 53b of the pair of first spring seats 52, 53 come into contact with each other. In other words, the contact of the pair of first spring seats 52 and 53 restricts the movement of the first spool 41 against the biasing force of the first spring 51. When the first spool 41 moves until the pair of first spring seats 52, 53 come into contact with each other, the second pump passage 11 communicates with the main passage 12 through the second annular groove 43b, as shown in FIG. Further, the downstream passage 10b of the first pump passage 10 is blocked from communicating with the main passage 12 by the second land portion 42b, and communicates with the fourth tank passage 16d through the first annular groove 43a. In this state, the regulation nut 57 is tightened with respect to the housing 90 to regulate the change in the screwing position of the switching bolt 56 (the position of the first spool 41). In this way, the switching valve 40 is switched to the second switching position 40B.

When switching the switching valve 40 from the second switching position 40B (the state shown in FIG. 6) to the first switching position 40A (the state shown in FIG. 4), the regulating nut 57 is loosened so that it is separated from the first spool 41. The switching bolt 56 is rotated. As a result, the first spool 41 receives the biasing force of the first spring 51 and moves together with the one first spring seat 52 so as to follow the switching bolt 56 separated from the first spool 41. The first spool 41 moves under the biasing force of the first spring 51 until one of the first spring seats 52 contacts the step surface 50d between the first large diameter hole 50a and the first small diameter hole 50b. .. When the first spool 41 moves until the first spring seat 52 contacts the step surface 50d between the first large diameter hole 50a and the first small diameter hole 50b, as shown in FIG. The downstream passage 10b and the main passage 12 communicate with each other through the first annular groove 43a. Further, the second pump passage 11 communicates with the third tank passage 16c through the second annular groove 43b. In this state, the restriction nut 57 is tightened with respect to the housing 90 to restrict the change in the screwing position of the switching bolt 56. In this way, the switching valve 40 is switched from the second switching position 40B to the first position 40A.

As described above, the position of the switching valve 40 can be switched by manually operating the switching unit 55.

Here, in general, in a fluid pressure control device incorporating a switching valve that is switched by a manual operation, an inspection at the time of shipment may be performed by an automatic inspection line in an inspection process at the time of manufacturing. However, when the manually operated switching valve is incorporated in the fluid pressure control device, it is necessary for the operator to manually check the operation of the switching valve separately from the inspection by the automatic inspection line. Further, when the space around the switching portion of the switching valve is small, it becomes difficult to operate the switching portion, and a lot of man-hours are required for the step of confirming the operation of the switching valve. As described above, there are cases where it is desired to operate a switching valve which is manually operated by a signal from the outside even when the operation is confirmed by an automatic inspection line together with the fluid pressure control device. However, in the manual switching valve, it is desirable that the inside of the first cap be communicated with the tank in order to prevent malfunction due to the pressure buildup inside the first cap. Therefore, generally, even if the pilot pressure is supplied to the inside of the first cap, the pilot pressure does not act on the first spool, and it is difficult to move the first spool.

In contrast, in the switching valve 40 according to the present embodiment, the throttle passage 49b is provided in the drain passage 18 that guides the hydraulic oil in the internal pressure chamber 58 of the first cap 50 to the tank T. As a result, the internal pressure chamber 58 always communicates with the tank T, but resistance is imparted to the hydraulic oil passing through the throttle passage 49b. Therefore, the pressure of the internal pressure chamber 58, to which the pilot pressure is guided, does not decrease to the tank pressure by the throttle passage 49b and is maintained at a predetermined pressure. Thereby, when the pilot pressure is supplied to the internal pressure chamber 58 in the state where the switching valve 40 is in the first switching position 40A, the slit 48a of the first head portion 48 is passed through the slit 52c in the flange portion 52a of the one first spring seat 52. A pressure higher than the tank pressure acts (see FIG. 4). The pressure acting on the first head portion 48 urges the first spool 41 against the urging force of the first spring 51. Therefore, as shown in FIG. 7, the pressure generated in the internal pressure chamber 58 causes the switching valve 40 to move to the second switching position 40B even when the switching unit 55 is not operated, while the pilot pressure is being supplied to the internal pressure chamber 58. Is switched to. When the supply of the pilot pressure to the internal pressure chamber 58 is stopped, the pressure in the internal pressure chamber 58 is discharged to the tank T through the drain passage 18. Therefore, the first spool 41 moves by receiving the biasing force of the first spring 51 and is switched to the first switching position 40A.

As described above, the switching valve 40 can switch the position by the pilot pressure in addition to the switching by the manual operation. Since the manually operated switching valve 40 can be operated by a signal from the outside, the operation of the switching valve 40 can be confirmed by an automatic inspection line, and the number of steps required for the inspection process can be reduced. You can It should be noted that the operation of the switching valve 40 by the pilot pressure is not limited to the case of inspecting in an automatic inspection line, and may be executed in other situations.

The bypass cut valve 60 is held at the open position 60A by the urging force of the second spring 71 when the pilot pressure is not guided to the pilot chamber 78. At the open position 60A, as shown in FIG. 4, the upstream passage 10a and the downstream passage 10b communicate with each other through the third annular groove 63a and the fourth annular groove 63b of the second spool 61, and the first pump passage 10 is opened. It

When the bypass cut valve 60 is switched from the open position 60A (state shown in FIG. 4) to the cutoff position 60B (state shown in FIG. 6), pilot pressure is introduced into the pilot chamber 78 of the bypass cut valve 60. As a result, the second spool 61 receives the pilot pressure and moves against the biasing force of the second spring 71. The second spool 61 moves against the biasing force of the second spring 71 until the boss portions 72b, 73b of the pair of second spring seats 72, 73 come into contact with each other. As a result, as shown in FIG. 6, the communication between the upstream passage 10a and the downstream passage 10b is blocked by the fifth land portion 62b and the sixth land portion 62c of the second spool 61, and the first pump passage 10 is blocked. It In this way, the bypass cut valve 60 becomes the shutoff position 60B.

As described above, even when the switching valve 40 is switched to the second switching position 40B and the bypass cut valve 60 is switched to the shutoff position 60B, the first spool 41 and the second spool 61 do not come into contact with each other. Separate (see FIG. 6). Therefore, the switching valve 40 and the bypass cut valve 60 are prevented from affecting each other's operation.

Further, since the switching valve 40 and the bypass cut valve 60 are two-position spool valves, respectively, the first spool 41 and the second spool 61 can be inserted coaxially into one accommodation hole 91. .. Even in this case, the operations of the switching valve 40 and the bypass cut valve 60 do not affect each other. Therefore, as compared with the case where the first spool 41 and the second spool 61 are inserted into separate accommodation holes, respectively, the housing 90 can be downsized and the cost for processing the accommodation hole 91 can be reduced.

Next, a modified example of the present embodiment will be described.

In the above embodiment, the first spool 41 of the switching valve 40 and the second spool 61 of the bypass cut valve 60 are inserted into the accommodation hole 91 which is a through hole having a uniform inner diameter. An internal space 92 is formed between the first spool 41 and the second spool 61. On the other hand, for example, a partition wall portion is provided between the first spool 41 and the second spool 61, and the housing hole 91 for housing the first spool 41 and the housing hole 91 for housing the second spool 61 are partitioned. It may be separated by parts. In this case, in order to discharge the pressure of the internal pressure chamber 58 in the first cap 50 to the tank T, the partition wall is formed with a hole that communicates with the accommodation hole 91 that accommodates the first spool 41 and the second spool 61. Is desirable. Further, in this case, a diaphragm may be provided in the partition.

According to the above embodiment, the following effects are exhibited.

In the fluid pressure control device 100, by switching the position of the switching valve 40 by a manual operation, hydraulic fluid is introduced from the first pump P1 to the second hydraulic cylinder 2 depending on the type of hydraulic excavator and the needs of the user, or It is possible to select whether to guide the hydraulic oil from the second pump P2 to the second hydraulic cylinder 2. Since the pump that supplies the hydraulic oil to the second hydraulic cylinder 2 can be selected by switching the switching valve 40, regardless of which pump the user drives the second hydraulic cylinder 2, the piping of the fluid pressure control device 100 can be selected. The structure can be common. Therefore, the manufacturing cost of the fluid pressure control device 100 can be reduced.

Further, in the fluid pressure control device 100, the first spool 41 of the switching valve 40 and the second spool 61 of the bypass cut valve 60 are inserted so as to face one accommodation hole 91. As a result, it is possible to prevent the housing 90 from increasing in size and reduce the manufacturing cost.

Further, in the fluid pressure control device 100, since the throttle passage 49b as the throttle portion is formed in the drain passage 18, the position of the switching valve 40 can be switched by a manual operation, and the switching valve 40 is supplied to the internal pressure chamber 58. The position can also be switched by pilot pressure. Accordingly, for example, the operation of the manually operated switching valve 40 can be confirmed on an automatic inspection line, and the fluid pressure control device 100 can be easily manufactured.

Hereinafter, the configuration, operation, and effect of the embodiment of the present invention will be collectively described.

The fluid pressure control device 100 includes a first pump passage 10 that guides the hydraulic oil discharged from the first pump P1, a second pump passage 11 that guides the hydraulic oil discharged from the second pump P2, and a first pump P1 or The hydraulic fluid discharged from the second pump P2 is selectively guided to the main passage 12 communicating with the tank T and the flow of the hydraulic fluid supplied to and discharged from the first hydraulic cylinder 1 provided in the first pump passage 10. A first control valve 20 for controlling, a second control valve 30 provided in the main passage 12 for controlling the flow of hydraulic oil supplied to and discharged from the second hydraulic cylinder 2, and a second control valve branched from the main passage 12. Second branch passage 14 that guides the hydraulic oil to 30, a parallel passage 15 that branches from the first pump passage 10 and is connected to the second branch passage 14, and a second branch from the first pump P1 provided in the parallel passage 15 A third check valve 83 that allows only the flow of hydraulic oil toward the passage 14 and a passage that is provided in the main passage 12 and communicates with the main passage 12 among the first pump passage 10 and the second pump passage 11 are selectively selected. A switching valve 40 for switching, and the switching valve 40 includes a first switching position 40A that communicates the first pump passage 10 and the main passage 12, and a second switching position that communicates the second pump passage 11 and the main passage 12. And a position 40B.

In this configuration, when the switching valve 40 is in the first switching position 40A, the main passage 12 that guides the hydraulic oil to the second control valve 30 communicates with the first pump passage 10, and the second control valve 30 has the first The hydraulic oil discharged from the pump P1 is introduced. Therefore, the first hydraulic cylinder 1 and the second hydraulic cylinder 2 are each operated by the hydraulic oil discharged from the first pump P1. When the switching valve 40 is set to the second switching position 40B, the main passage 12 communicates with the second pump passage 11, and the hydraulic oil discharged from the second pump P2 is guided to the second control valve 30. Therefore, the first hydraulic cylinder 1 operates independently of each other by the hydraulic oil discharged from the first pump P1, and the second hydraulic cylinder 2 operates independently of each other by the hydraulic oil discharged from the second pump P2. In this way, by switching the position of the switching valve 40, it is possible to select whether to guide the hydraulic oil from the first pump P1 or the hydraulic oil from the second pump P2 to the second control valve 30. Therefore, the piping structure can be made common regardless of which of the first pump P1 and the second pump P2 the hydraulic oil is guided to the second control valve 30. Therefore, the manufacturing cost of the fluid pressure control device 100 is reduced.

Further, in the fluid pressure control device 100, the first actuator is a hydraulic cylinder that expands and contracts due to the pressure difference between the bottom side chamber 7 and the rod side chamber 6 on which the load of the boom 102 acts, and the first control valve 20 is the first It has a first neutral position 20A for opening the pump passage 10 and a first contraction position 20C for opening the first pump passage 10 and communicating the first pump passage 10 and the rod side chamber 6 with each other. The valve 30 has a second neutral position 30A that communicates the main passage 12 with the tank T, and a supply position (second extension position 30B, second extension position 30B that supplies the hydraulic oil guided from the second branch passage 14 to the second hydraulic cylinder 2). The contraction position 30C), and the switching valve 40 connects the second pump passage 11 and the tank T in the first switching position 40A, and connects the first pump passage 10 and the tank T in the second switching position 40B. A bypass cut valve 60 that switches between opening and closing of the first pump passage 10 is provided downstream of the first control valve 20 in the first pump passage 10.

With this configuration, the bypass cut valve 60 is provided when the switching valve 40 is in the first switching position 40A and the second control valve 30 is in the second neutral position 30A, and when the switching valve 40 is in the second switching position 40B. Opens the first pump passage 10 and sets the first control valve 20 to the first contraction position 20C, the first pump passage 10 communicates with the tank T. In this case, the hydraulic oil discharged from the first pump P1 is not supplied to the first hydraulic cylinder 1, and the first hydraulic cylinder 1 operates by its own weight of the load. On the other hand, when the first control valve 20 is switched to the first contraction position 20C with the bypass cut valve 60 blocking the first pump passage 10, the communication between the first pump passage 10 and the tank T is blocked. Therefore, the hydraulic oil discharged from the first pump P1 is supplied to the first hydraulic cylinder 1. Therefore, the first hydraulic cylinder 1 contracts due to the pressure of the hydraulic oil discharged from the first pump P1. In this way, by switching the opening and closing of the first pump passage 10 by the bypass cut valve 60, it is possible to drive the first hydraulic cylinder 1 by both drive by load and drive by hydraulic pressure.

Further, the fluid pressure control device 100 further includes a housing 90 that houses the switching valve 40 and the bypass cut valve 60, the switching valve 40 has a first spool 41 that switches the position, and the bypass cut valve 60 changes the position. The first spool 41 of the switching valve 40 and the second spool 61 of the bypass cut valve 60 are coaxially housed in the housing hole 91 formed in the housing 90 so as to face each other. It

With this configuration, the housing 90 can be made compact.

Further, in the fluid pressure control device 100, the accommodation hole 91 is formed as a through hole whose both ends open to the end surfaces 90 a and 90 b of the housing 90, and the switching valve 40 is attached to the housing 90 and one opening of the accommodation hole 91 is formed. A first cap 50 for sealing, an internal pressure chamber 58 formed in the first cap 50, and a first spool provided in the first cap 50 for urging the first spool 41 in a direction separating from the second spool 61. The bypass cut valve 60 further includes a spring 51 and a switching unit 55 that is provided on the first cap 50 and that moves the first spool 41 against the biasing force of the first spring 51 by manual operation. The second cap 70 that is attached to 90 and seals the other opening of the accommodation hole 91, and the pilot pressure that is formed in the second cap 70 and that urges the second spool 61 toward the first spool 41 is the pilot port 70c. And a second spring 71 that is provided in the second cap 70 and that biases the second spool 61 in the direction away from the first spool 41.

Further, in the fluid pressure control device 100, the first cap 50 is provided with an introduction port 50c for guiding the pilot pressure for moving the first spool 41 against the urging force of the first spring 51 to the internal pressure chamber 58. The internal pressure chamber 58 in the one cap 50 is in constant communication with the tank T through the drain passage 18, and the drain passage 18 is provided with a throttle passage 49b that imparts resistance to the flow of the working fluid passing therethrough.

Further, in the fluid pressure control device 100, the drain passage 18 includes the internal space 92 defined by the end portion of the first spool 41 and the end portion of the second spool 61 facing each other in the accommodation hole 91, and the first spool. There is a first internal passage 49 formed in 41 for communicating the internal pressure chamber 58 with the internal space 92, and a second internal passage 69 formed in the second spool 61 for communicating the internal space 92 with the tank T.

In these configurations, when the pilot pressure is introduced into the internal pressure chamber 58, a part of the hydraulic oil in the internal pressure chamber 58 is discharged through the drain passage 18, but resistance is imparted by the throttle passage 49b, so that the internal pressure chamber 58 receives the resistance. Generates a predetermined pressure. Therefore, by supplying the pilot pressure to the internal pressure chamber 58, a thrust force for moving the first spool 41 is generated in the internal pressure chamber 58, and the first spool 41 can be moved.

Further, in the fluid pressure control device 100, the switching valve 40 further includes a pair of first spring seats 52 and 53 that are seated at both ends of the first spring 51 and move relative to each other as the first spring 51 expands and contracts. The cut valve 60 further includes a pair of second spring seats 72 and 73 which are seated at both ends of the second spring 71 and move relative to each other as the second spring 71 expands and contracts. By contacting each other, the movement of the first spool 41 against the biasing force of the first spring 51 is regulated, and when the pair of second spring seats 72, 73 contact each other, the biasing force of the second spring 71 is increased. The movement of the second spool 61 against the movement is restricted.

With this configuration, the movement amounts of the first spool 41 and the second spool 61 can be easily set.

Further, in the fluid pressure control device 100, the first spool 41 is attached to the first main body portion 42 that is in sliding contact with the inner peripheral surface of the accommodation hole 91 and the end portion of the first main body portion 42, and the first spring 51 is provided on the outer periphery. The second spool 61 is attached to the end portion of the second main body portion 62 and the second main body portion 62 that is in sliding contact with the inner peripheral surface of the accommodation hole 91. A second support portion 66 provided with a second spring 71, the first main body portion 42 axially projects toward the first support portion 46, and the first support portion 46 comes into contact with the second small diameter. The second body portion 62 has a portion 45, and the second main body portion 62 has a third small diameter portion 64 that projects in the axial direction toward the second support portion 66 and is in contact with the second support portion 66.

In this configuration, by changing the protrusion amount of the second small diameter portion 45 and the third small diameter portion 64, the first support portion 46, the second support portion 66, the first spring seats 52 and 53, and the second spring seat 72. , 73 can be commonly used, and the movement amounts of the first spool 41 and the second spool 61 can be changed.

Further, in the fluid pressure control device 100, the accommodation hole 91 is formed as a through hole having a uniform inner diameter.

With this configuration, since the inner peripheral surface of the accommodation hole 91 can be polished and finished, the processing accuracy of the accommodation hole 91 is improved.

Although the embodiment of the present invention has been described above, the above embodiment merely shows a part of the application example of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. Absent.

1... 1st hydraulic cylinder (1st actuator), 2... 2nd hydraulic cylinder (2nd actuator), 10... 1st pump passage, 11... 2nd pump passage, 12... Main passage, 14... 2nd branch passage ( Supply passage), 15... parallel passage, 18... drain passage, 20... first control valve, 30... second control valve, 40... switching valve, 41... first spool, 42... first main body portion, 45... second Small-diameter portion (first protruding portion), 46... First support portion, 49... First internal passage, 49b... Throttling passage (throttle portion), 50... First cap, 50c... Introduction port, 51... First spring (first) 1 urging member), 52, 53... First spring seat (first seating member), 55... Switching portion, 58... Internal pressure chamber, 60... Bypass cut valve, 61... Second spool, 62... Second body portion, 64... 3rd small diameter part (2nd protrusion part), 66... 2nd support part, 69... 2nd internal passage, 70... 2nd cap, 71... 2nd spring (2nd biasing member), 72, 73... Second spring seat (second seat member), 83... Third check valve (check valve), 90... Housing, 91... Housing hole, 92... Internal space, 100... Fluid pressure control device, P1... First pump , P2...Second pump, T...Tank

Claims (9)

A first pump passage for guiding a working fluid discharged from the first pump;
A second pump passage for guiding the working fluid discharged from the second pump;
A main passage through which a working fluid discharged from the first pump or the second pump is selectively guided;
A first control valve provided in the first pump passage for controlling the flow of the working fluid supplied to and discharged from the first actuator;
A second control valve provided in the main passage for controlling the flow of the working fluid supplied to and discharged from the second actuator;
A supply passage branched from the main passage to guide the working fluid to the second control valve;
A parallel passage branched from the first pump passage and connected to the supply passage;
A check valve which is provided in the parallel passage and allows only the flow of the working fluid from the first pump to the supply passage;
A switching valve provided in the main passage for selectively switching a passage communicating with the main passage among the first pump passage and the second pump passage,
The switching valve is
A first switching position that connects the first pump passage and the main passage,
A fluid pressure control device comprising: a second switching position that connects the second pump passage and the main passage. The first actuator is a fluid pressure cylinder that expands and contracts due to a pressure difference between a load side pressure chamber in which a load to be driven acts and an anti-load side pressure chamber,
The first control valve is
A first neutral position for opening the first pump passage,
A drive position that opens the first pump passage and communicates the first pump passage with the anti-load side pressure chamber;
The second control valve is
A second neutral position for communicating the main passage with the tank;
A supply position for supplying the working fluid guided from the supply passage to the second actuator,
The switching valve is
Communicating the second pump passage and the tank at the first switching position, and communicating the first pump passage and the tank at the second switching position,
The fluid pressure control device according to claim 1, wherein a bypass cut valve that switches between opening and closing of the first pump passage is provided in the first pump passage downstream of the first control valve. .. Further comprising a housing that houses the switching valve and the bypass cut valve,
The switching valve has a first spool for switching the position,
The bypass cut valve has a second spool for switching the position,
The first spool of the switching valve and the second spool of the bypass cut valve are coaxially housed in a housing hole formed in the housing so as to face each other. The fluid pressure control device described. The accommodation hole is formed as a through hole whose both ends open to an end surface of the housing,
The switching valve is
A first cap attached to the housing to seal one opening of the accommodation hole;
An internal pressure chamber formed in the first cap,
A first urging member provided in the first cap for urging the first spool in a direction of separating from the second spool;
A switching unit that is provided on the first cap and moves the first spool against a biasing force of the first biasing member by a manual operation;
The bypass cut valve is
A second cap attached to the housing for sealing the other opening of the accommodation hole;
A pilot chamber formed in the second cap, through which a pilot pressure for urging the second spool toward the first spool is introduced through a pilot port;
The fluid pressure according to claim 3, further comprising a second urging member that is provided in the second cap and urges the second spool in a direction in which the second spool is separated from the first spool. Control device. The first cap is formed with an introduction port that guides pilot pressure for moving the first spool to the internal pressure chamber against the urging force of the first urging member.
The internal pressure chamber in the first cap is in constant communication with the tank through a drain passage,
The fluid pressure control device according to claim 4, wherein the drain passage is provided with a throttle portion that imparts resistance to a flow of the working fluid passing therethrough. The drain passage is
An internal space defined in the accommodation hole by an end of the first spool and an end of the second spool that face each other;
A first internal passage formed in the first spool and connecting the internal pressure chamber and the internal space;
The fluid pressure control device according to claim 5, further comprising a second internal passage that is formed in the second spool and that communicates the internal space with the tank. The switching valve further includes a pair of first seating members on which both ends of the first biasing member are seated and relatively move as the first biasing member expands and contracts.
The bypass cut valve further includes a pair of second seating members that are seated at both ends of the second biasing member and move relative to each other as the second biasing member expands and contracts.
When the pair of first seat members come into contact with each other, movement of the first spool against the urging force of the first urging member is restricted,
7. The movement of the second spool against the urging force of the second urging member is restricted by contacting the pair of second seating members with each other, and the second spool is restricted from moving. And a fluid pressure control device. The first spool is
A first body portion that is in sliding contact with the inner peripheral surface of the accommodation hole;
A first support portion attached to an end portion of the first main body portion and provided with the first urging member on an outer periphery,
The second spool is
A second body portion that is in sliding contact with the inner peripheral surface of the accommodation hole;
A second support portion attached to an end portion of the second main body portion and provided with the second urging member on the outer periphery,
The first main body portion has a first protruding portion that axially protrudes toward the first support portion, and is in contact with the first support portion,
The fluid pressure control device according to claim 7, wherein the second main body portion has a second protrusion portion that axially protrudes toward the second support portion and is in contact with the second support portion. The fluid pressure control device according to claim 3, wherein the accommodation hole is formed as a through hole having a uniform inner diameter.

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