JP2014013062A - Fluid pressure control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid pressure control device whose configuration can be simplified.SOLUTION: A fluid pressure control device comprises: a booster 32 which generates high fluid pressure when a piston moves in a cylinder by fluid pressure from a hydraulic pump 3; a switching valve 30 whose valve position is switched so as to connect the hydraulic pump 3 with the booster 32 in a tank pressure load, and to connect a tank 11 with the booster 32 in a fluid pressure load from the hydraulic pump 3 with force larger than force acting on the piston by tank pressure and smaller than force acting on the piston by fluid pressure from the hydraulic pump 3; and a switching valve part whose valve position is switched so as to make the tank pressure be loaded onto the switching valve 30 when the piston is at a stroke end position in the fluid pressure load of the hydraulic pump 3 and to make the fluid pressure of the hydraulic pump 3 be loaded onto the switching valve 30 when the piston is at a stroke end position in the tank pressure load.

Description

  The present invention relates to a fluid pressure control device including a pressure booster.

  Conventionally, as a fluid pressure control device, a hydraulic control device including a pressure increasing device using a cylinder and a piston is known (see, for example, Patent Document 1). The pressure booster supplies high pressure oil by flowing low pressure oil from the low pressure side into the large diameter space in the cylinder and outflowing oil from the small diameter space in the cylinder to the high pressure side by reciprocating movement of the piston.

JP 2011-185417 A

  The above-described pressure boosting device requires inflow and outflow of fluid to generate and supply high-pressure oil, and generally has a configuration in which inflow and outflow of fluid are switched by an electric signal. However, when an electrical signal is used for switching between opening and closing of a valve, a device for outputting a control signal, a device for sensing a valve position, and the like are required, and the entire device is increased in size. In addition, a control program is required and there is a problem in terms of cost.

  An object of the present invention is to provide a fluid pressure control device capable of simplifying the configuration.

In order to achieve the above object, a fluid pressure control device according to the present invention provides:
A first fluid pressure supply unit for supplying a first fluid pressure;
A second fluid pressure supply unit for supplying a second fluid pressure higher than the first fluid pressure;
A cylinder and a piston that reciprocates in the cylinder, and the second fluid pressure is loaded and the piston moves in the cylinder, thereby generating a fluid pressure higher than the second fluid pressure. A pressure increasing part;
The force acting on the piston by the load of the first fluid pressure is greater than the force acting on the piston by the load of the second fluid pressure in the direction opposite to the stroke direction of the piston at the time of the second fluid pressure load. A biasing portion that biases the piston with a small force;
A first switching valve portion that switches a valve position according to a change in a fluid pressure to be loaded, wherein the second fluid pressure supply portion is connected to the pressure increasing portion when the first fluid pressure is loaded; A first switching valve section that switches to connect the first fluid pressure supply section to the pressure increasing section when a second fluid pressure is applied;
A second switching valve portion whose valve position is switched by movement of the piston, wherein the first fluid pressure supply portion is connected to the first switching valve portion when the piston is at a stroke end position at the time of a second fluid pressure load. When the fluid pressure is applied from the second fluid pressure supply portion, the first switching valve portion is switched so that the fluid pressure is loaded from the second fluid pressure supply portion when the piston is at the stroke end position at the time of the first fluid pressure load. Two switching valves,
It is characterized by providing.

According to the present invention, the piston can be continuously reciprocated by the cooperation of the first switching valve portion, the second switching valve portion, and the biasing portion that are mechanically operated. Therefore, a fluid pressure higher than the second fluid pressure can be continuously generated without performing electrical control. The specific operation in the configuration of the present invention is as follows.

  The first switching valve unit connects the second fluid pressure supply unit to the pressure increasing unit when the fluid pressure to be applied is the first fluid pressure. When the second fluid pressure is applied to the pressure increasing portion, the piston strokes in the cylinder against the urging force of the urging portion, and generates a fluid pressure higher than the second fluid pressure. When the piston reaches the end position of the stroke, the valve position of the second switching valve unit is switched, and the fluid pressure applied to the first switching valve unit is switched from the first fluid pressure to the second fluid pressure. When the second fluid pressure is applied to the first switching valve portion, the first fluid pressure supply portion is connected to the pressure increasing portion, and the load pressure of the piston is switched from the second fluid pressure to the first fluid pressure. The piston loaded with the first fluid pressure loses the urging force of the urging portion and strokes in the reverse direction in the cylinder. When the piston reaches the end position of the stroke, the valve position of the second switching valve portion is switched, and the fluid pressure applied to the first switching valve portion returns to the first fluid pressure again. By repeating the above operation, the reciprocating motion of the piston is repeated, and a high fluid pressure is repeatedly generated.

  As described above, according to the present invention, the reciprocating motion of the piston in the pressure increasing portion can be mechanically controlled. Therefore, conventional electric control is not required, and the configuration of the fluid pressure control circuit can be simplified.

  The first fluid pressure supply unit may include a throttle unit that regulates a flow rate of a fluid flowing through a flow path for applying a fluid pressure to the first switching valve unit.

  By providing such a throttle part, it is possible to control the rate of change of the fluid pressure applied to the first switching valve part. Thereby, the stroke time of the piston can be controlled.

  A pressure accumulating unit that accumulates a fluid pressure higher than the second fluid pressure generated in the pressure increasing unit and that can supply the accumulated fluid pressure to the downstream side may be provided.

  Thereby, the high fluid pressure repeatedly generated in the pressure increasing unit is accumulated in the pressure accumulating unit, so that a steady high fluid pressure can be supplied.

The pressure accumulator is
A pressure accumulating means capable of accumulating fluid that has been increased to a fluid pressure higher than the second fluid pressure by the pressure increasing unit;
Pressure detecting means for detecting the pressure of the fluid accumulated in the pressure accumulating means;
A switching valve provided on the downstream side of the pressure accumulating means,
A controller for controlling the accumulation of the increased fluid in the pressure accumulating means and the supply / non-supply of the fluid accumulated in the pressure accumulating means to the downstream side by switching the switching valve;
It is good to have.

  This makes it possible to arbitrarily control the timing of supplying the fluid pressure accumulated in the pressure accumulating unit to the downstream side and the magnitude of the fluid pressure supplied to the downstream side.

  The pressure accumulating unit may include a plurality of the pressure accumulating means.

  Thereby, while one of the plurality of pressure accumulating means is accumulating, the other pressure accumulating means supplies the high fluid pressure, i.e., the plurality of pressure accumulating means alternately supplies the high fluid pressure. By doing so, continuous supply of high fluid pressure becomes possible.

A check valve may be provided between the pressure accumulating unit and the supply destination of the fluid pressure accumulated in the pressure accumulating unit.

  By providing a check valve between the pressure accumulating unit and the high fluid pressure supply destination, the system can be divided between the check valve and the fluid pressure supply side, and from the check valve to the pressure accumulating unit side (upstream side). . As a result, even when the fluid pressure supply side is a high pressure specification, it is possible to supply a high fluid pressure without making each element on the pressure accumulating unit side a high pressure specification.

  ADVANTAGE OF THE INVENTION According to this invention, simplification of the structure of the fluid pressure control apparatus provided with the pressure increase part can be achieved.

Hydraulic circuit diagram of fluid pressure control device according to an embodiment of the present invention The figure which shows the secondary pressure characteristic of the hydraulic remote control valve Enlarged view of the pressure booster in FIG. Schematic diagram showing another example of a pressure booster

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be exemplarily described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. .

<Example>
FIG. 1 is a hydraulic circuit diagram of a hydraulic control device (fluid pressure control device) according to an embodiment of the present invention. The hydraulic control apparatus according to the present embodiment can be applied to hydraulic apparatuses such as brakes, steerings, transmissions, and the like in ordinary passenger cars, trucks, hydraulic excavators, forklifts, cranes, garbage trucks, and the like. The hydraulic circuit shown in FIG. 1 is merely an example of the fluid pressure circuit of the fluid pressure control device of the present invention, and is not limited to the configuration of FIG.

  The hydraulic control apparatus according to the present embodiment is generally configured to transmit the power of the drive mechanism 1 such as an engine or an electric motor to the target W by controlling the hydraulic pressure. The drive mechanism 1 may also serve as a power source for other mechanisms in the vehicle, or may be a dedicated power source for the hydraulic control device.

  The drive mechanism 1 is connected to a main circuit hydraulic pump 2 (hereinafter referred to as a hydraulic pump 2), which is a so-called variable displacement pump, and a pilot circuit hydraulic pump 3 (hereinafter referred to as a hydraulic pump 3). Driven. The hydraulic pump 2 and the hydraulic pump 3 are rotated by power from the drive mechanism 1 to supply hydraulic pressure to the downstream side via the hydraulic lines 12 and 18.

  The pressure oil discharged from the hydraulic pump 2 flows into the switching valve 4 through the oil passage 13. The switching valve 4 is a 6-port 3-position open center type switching valve, and in its neutral position, the entire amount of pressure oil discharged from the hydraulic pump 2 flows to the tank 11 through the oil passage 14.

  The pressure oil discharged from the hydraulic pump 3 is supplied to the hydraulic remote control valve 6 (hereinafter referred to as the remote control valve 6) through the oil passage 18. The remote control valve 6 is a variable pressure reducing valve. When the lever 6-1 is operated back and forth, the reduced secondary pressure passes through the signal oil passages 21 and 22 and the signal port 4- of the switching valve 4. 1 and 4-2.

FIG. 2 is a diagram showing the secondary pressure characteristics of the hydraulic remote control valve 6. When the lever 6-1 is operated in the extending or contracting direction, a secondary pressure Px proportional to the lever operating amount Lx as shown in FIG. 2 is supplied to the signal port 4-1 or 4-2 of the switching valve 4. The switching valve 4 is switched to the “extended” position or the “shrinked” position. Of the pressure oil discharged from the pump 3, excess oil that is not supplied from the remote control valve 6 to the signal ports 4-1 and 4-2 is supplied to the pressure booster 32 side through the oil passage 26. Excluding the oil, the oil is discharged to the tank 11 through the oil passage 19, the relief valve 8, and the oil passage 20.

  When the operation lever 6-1 of the remote control valve 6 is operated in the contracted direction and the switching valve 4 is switched to the contracted position, the pressure oil from the pump 2 passes through the oil passages 12 and 15, the switching valve 4 and the oil passage 24. It flows into the oil chamber 5-1 of the cylinder 5. The rod in the cylinder 5 moves to the contracted position due to the inflow of pressurized oil into the oil chamber 5-1, and the oil in the oil chamber 5-2 passes through the oil passage 23, the switching valve 4, and the oil passage 25 to the tank 11. Discharged. At this time, an electrical signal from the pressure sensor 10 installed on the pilot signal oil passage 22 is input to the controller 34.

  When the switching valve 4 is switched to the extended position by operating the operation lever 6-1 in the extending direction, the pressure oil from the pump 2 passes through the oil passages 12 and 15, the switching valve 4 and the oil passage 23, and the oil in the cylinder 5 It flows into the chamber 5-2. The rod in the cylinder 5 moves to the extended position by the inflow of pressurized oil into the oil chamber 5-2, and the oil in the oil chamber 5-1 passes through the oil passage 24 and the oil passage 25 through the switching valve 4. And discharged to the tank 11. At this time, an electrical signal from the pressure sensor 9 installed on the pilot signal oil passage 21 is input to the controller 34.

  The power of the drive mechanism 1 is transmitted to the target W by the movement of the rod in the cylinder 5 described above. It should be noted that when the rod in the cylinder 5 reaches the end of expansion or contraction or when a sudden load is applied to the cylinder 5, the oil in the circuit may become in a closed state and become an abnormally high pressure. In this circuit, a relief valve 7 is installed to prevent the oil machine in the circuit from being damaged when such an abnormally high pressure state occurs. The abnormal high pressure oil is discharged to the tank 11 through the oil passage 16, the relief valve 7, and the oil passage 17.

(Pressure booster)
An electromagnetic switching valve 27 is provided on the oil passage 26 branched from the oil passage 18. In the electromagnetic switching valve 27, the oil passage 26 and the oil passage 28 are blocked at the neutral position. At the same time, the oil passage 28 is connected to the tank 11 (first fluid pressure supply unit) via the electromagnetic switching valve 27 and the oil passage 29. It is connected. The oil passage 28 is connected to a pressure booster (pressure booster) 32 via a switching valve 30 and an oil passage 31.

  When the switch 33 is turned on, the electromagnetic switching valve 27 is switched by inputting an electric signal from the controller 34 through the electric signal line 68, and the oil passage 26 and the oil passage 28 are connected. And the oil passage 29 is blocked.

  FIG. 3 is an enlarged schematic diagram showing the pressure booster 32 in FIG. As shown in FIG. 3, in the pressure increasing device 32, a piston 32-2 is enclosed in a case (cylinder) 32-1, and slides in the case. The piston 32-2 is in contact with the guide portion 32-3a of the switching valve portion 32-3 at the end surface 32-2b, and the biasing force of the spring (biasing portion) 32-4 causes the guide portion 32-3a. The end face is always pressed against the piston end face 32-2b.

  In a state where the load pressure on the piston end surface 32-2a is low, that is, a state where a tank pressure (first fluid pressure) is applied, the piston 32-2 is urged by the urging force of the spring 32-4 so that the piston 32-2 It is pressed against the end portion 32-1a in 32-1. Further, at the switching valve portion (second switching valve portion) 32-3, the pilot oil passage 35 and the drain oil passage 36 are connected, and the pilot oil passage 37 is shut off at the same time as being connected to the tank 11. .

  Next, when a load pressure higher than a predetermined value is applied to the piston end surface 32-2a, that is, the pressure oil (working fluid of the second fluid pressure) discharged from the hydraulic pump 3 (second fluid pressure supply unit) is loaded. The piston 32-2 moves to the left until the piston end surface 32-2b hits the stopper portion 32-1b of the case 32-1 against the urging force of the spring 32-4. At this time, the switching valve portion 32-3 is switched immediately before the piston end surface 32-2b hits the stopper portion 32-1b of the case 32-1, the pilot oil passages 35 and 37 are connected, and the drain oil passage 36 is shut off.

  The piston 32-2 is provided with a step by having a large-diameter portion and a small-diameter portion, and a passage 32 that conducts between the end portion 32-2a of the large-diameter portion and the annular end surface 32-2c of the step portion. A check valve 32-6 is installed on -5. The small diameter drain chamber 32-7 is connected to the tank 11 via an oil passage 66.

  The pilot oil passage 35 is connected to a signal port of the switching valve 30 through an adjustable slow return valve 38 and a pilot oil passage 39. In the pilot oil passage 35, the hydraulic signal from the switching valve portion 32-3 of the pressure booster 32 is throttled by the variable throttle portion 38-1 (throttle portion) of the slow return valve 38. Conversely, the hydraulic signal from the switching valve 30 flows through the check valve 38-2 of the slow return valve 38 to the switching valve portion 32-2 of the pressure increasing device 32 without being throttled. The pilot oil passage 37 is connected to the oil passage 28. The check valve 38-2 is released when hydraulic oil flows in the direction from the switching valve 30 toward the switching valve portion 32-3, and flows in the direction from the switching valve portion 32-3 toward the switching valve 30. Sometimes the valve is configured to be closed. Hereinafter, the other check valves have the same configuration.

here,
S1: Large-diameter cross-sectional area of the piston end surface 32-2a S2: Cross-sectional area of the stepped portion 32-2c F1: The spring when the piston 32-2 is pressed against the end 32-1a of the case 32-1 Energizing force P1x: Load pressure on the piston end surface 32-2a when the piston 32-2 is pressed by the end 32-1a of the case 32-1 P2x: Piston 32-2 is the end of the case 32-1 Load pressure applied to the stepped portion 32-2c when pressed against the 32-1a portion F2: Spring biasing force P1y when the piston 32-2 is pressed against the stopper portion 32-1b of the case 32-1 Load pressure on the piston end surface 32-2a when the piston 32-2 is pressed by the stopper portion 32-1b of the case 32-1 P2y: the piston 32-2 is the stopper portion 32-1 of the case 32-1 Assuming that the load pressure is applied to the stepped portion 32-2c when pressed by b, the following two equations are established.
P2x · S2 + F1 ≧ P1x · S1 (Formula 1)
P2y · S2 + F2 ≦ P1y · S1 (Formula 2)

(Accumulator pressure accumulation)
When the switch 33 is turned on, an electric signal is input from the controller 34 to the electromagnetic switching valve 27 via the electric signal line 68 (ON state), the electromagnetic switching valve 27 is switched, and the oil passage 26 and the oil passage 28 are connected. . Thus, the pressure oil Pp (≧ P1y) from the hydraulic pump 3 is loaded on the piston end surface 32-2a of the pressure increasing device 32 via the switching valve 30. From Equation 2, the piston 32-2 moves to the left until it hits the stopper portion 32-1b of the case 32-1 (to the stroke end position at the time of the second fluid pressure load). The oil in the stepped portion oil chamber 32-8 that has been made high pressure by the stroke of the piston 32-2 flows into the oil passage 42 through the oil passage 40 and the check valve 41, and the oil passages 43 and 44, Accumulator 49, 5 as pressure accumulating means through valves 45, 46
Accumulated to 0 respectively. Here, by setting S1 to a sufficiently large value compared to S2, it is possible to set the pushing pressure to each accumulator 49, 50 to a sufficiently high pressure by Pascal's theorem. The accumulators 49 and 50 can adopt conventional techniques as appropriate. For example, a pressure accumulating chamber and a back pressure chamber that are hermetically partitioned by a piston or an elastic body are provided.When the pressure in the pressure accumulating chamber exceeds the pressure in the back pressure chamber, the volume of the accumulating chamber is increased by the movement of the piston or the deformation of the elastic body. A configuration in which hydraulic pressure is accumulated by being enlarged is known.

  Further, if the switching valve portion 32-3 is switched immediately before the piston 32-2 hits the stopper portion 32-1b of the case 32-1, the pilot oil passages 35 and 37 are connected, so that the pressure signal from the oil passage 28 is slow. The signal is input to the signal port of the switching valve 30 through the variable throttle 38-1 of the return valve 38. As a result, when the switching valve 30 is switched, the oil passage 28 and the oil passage 31 are shut off, and at the same time, the oil passage 31 is conducted to the tank 11 through the drain oil passage 69, and the piston end face 32-2 a of the pressure increasing device 32. The load pressure to the part becomes the tank pressure. According to Equation 1, the piston 32-2 is pushed back to the position where the piston end surface 32-2a is pressed against the case end 32-1a by the urging force of the spring 32-4 (stroke end position at the time of the first fluid pressure load). It is. At this time, oil flows from the tank 11 into the stepped portion oil chamber 32-8 through the oil passages 69, 31, 32-5 and the check valve 32-6. In addition, as shown in FIG. 4, the level difference part oil chamber 32-8 is provided with an oil passage 32-5 ′ that directly circulates to the outside of the case 32-1, instead of the oil passage 32-5 that penetrates the piston 32-2. In addition, a check valve 32-6 ′ may be provided to connect to the oil passage 31. FIG. 4 is a schematic view showing another example of the pressure booster in the embodiment of the present invention.

  At the same time, when the switching valve section 32-3 is also returned to the neutral position, the signal port pressure of the switching valve 30 is reduced to the tank pressure at the moment when the pilot oil passage 35 is connected to the tank through the drain oil passage 36. . As a result, the spring in which the switching valve 30 is built returns to the neutral position, the oil passage 28 and the oil passage 31 are again conducted, and the pressure oil Pp from the hydraulic pump 3 is loaded on the end face 32-2a of the piston 32-2. Is done. From Equation 2 again, the piston 32-2 moves to the left until it hits the stopper portion 32-1b of the case 32-1, and the oil in the step portion oil chamber 32-8 is oil passage 40, check valve 41, oil passage. 42 is introduced into the oil passage 42, and is accumulated in the accumulators 49 and 50 through the oil passages 43 and 44 and the check valves 45 and 46. The above process is continuously repeated. That is, when the switch 33 is turned on, the pressure oil can be continuously accumulated in the accumulators 49 and 50 by the pressure increasing device 32.

  It should be noted that the pressure accumulation speed of the accumulators 49 and 50 by the pressure increasing device 32 can be adjusted by changing the switching timing of the switching valve 30 by adjusting the opening degree of the variable throttle portion 38-1 of the slow return valve 38. .

(Regeneration of accumulated oil)
The configuration of the pressure accumulating unit in the present embodiment will be described. On the oil passages 47 and 48, pressure sensors 51 and 52 are installed as pressure detecting means, respectively. Further, normally closed electromagnetic proportional switching valves 57 and 58 are connected through oil passages 53 and 54 branched from the oil passages 47 and 48 and check valves 55 and 56. The electromagnetic proportional switching valves 57 and 58 are connected to the oil passage 23 via oil passages 59 and 60, a check valve 61 and an oil passage 62. In addition, when the capacity of the accumulators 49 and 50 reaches an allowable capacity, excess oil is discharged to the tank 11 through the relief valve 66 and the oil path 67 installed on the oil path 42. The set pressure of the relief valve 66 may be set slightly higher than the hydraulic pressure required for regeneration to the cylinder 5, and the set pressure is sufficiently lower than that of the relief valve 7 used in the main circuit. Is possible.

The controller 34 controls the pressure accumulation in the accumulators 49 and 50 and the supply / non-supply of the pressure oil accumulated in the accumulators 49 and 50 to the downstream side by switching the electromagnetic proportional switching valves 57 and 58. That is, when the operation lever 6-1 is operated in the extending direction, the switching valve 4 is switched to the extended position, and the pressure oil from the pump 2 passes through the oil passages 12 and 15, the switching valve 4 and the oil passage 23, and the cylinder 5 The oil flows into the oil chamber 5-2, and the oil in the oil chamber 5-1 is discharged to the tank 11 through the oil passage 24, the switching valve 4, and the oil passage 25. At this time, when an electrical signal from the pressure sensor 9 is input to the controller 34, the electrical signal is first input to the electromagnetic proportional switching valve 57 through the electrical signal line 63 by an arithmetic circuit mounted in advance on the controller. . When the electromagnetic proportional switching valve 57 is switched, the accumulated oil in the accumulator 49 passes through the oil passage 53, the check valve 55, the electromagnetic proportional switching valve 57, the oil passage 59, the check valve 61, and the oil passage 62. It joins the passage 23 and is regenerated in the oil chamber 5-2 of the cylinder 5. At this time, an electric signal is simultaneously input from the controller 34 to the driving mechanism 1 through the electric signal line 65, and the driving force is reduced. That is, the operation in the extending direction of the operation lever 6-1 becomes a switch for increasing pressure (regenerating accumulated pressure).

  Further, when the pressure in the accumulator 49 falls below a predetermined value, an electrical signal from the pressure sensor 51 is input to the controller 34, and the electrical signal is electromagnetically transmitted through the electrical signal line 64 by an arithmetic circuit mounted in advance on the controller. Input to the proportional switching valve 58. Then, the electromagnetic proportional switching valve 58 is switched, and the accumulated oil in the accumulator 50 passes through the oil passage 54, the check valve 56, the electromagnetic proportional switching valve 58, the oil passage 60, the check valve 61, and the oil passage 62, and the oil passage 23. And is regenerated in the oil chamber 5-2 of the cylinder 5.

  At the same time, the electric signal to the electromagnetic proportional switching valve 57 is cut off and closed, whereby the pressure oil from the pressure increasing circuit 32 is accumulated in the accumulator 49 again. When the amount of accumulated pressure in the accumulator 50 decreases to a predetermined pressure or less, the electrical signal is received via the electrical signal line 63 by an arithmetic circuit that is mounted in advance on the controller 34 in response to the electrical signal from the pressure sensor 52. Input to the electromagnetic proportional switching valve 57. Then, the electromagnetic proportional switching valve 57 is switched, and the accumulated oil in the accumulator 49 again joins the oil passage 23 through the oil passage 59, the check valve 61, and the oil passage 62, and the oil chamber 5-2 of the cylinder 5 It is regenerated.

  By configuring the arithmetic circuit as described above, the pressure oil generated from the pressure booster accumulated in the accumulators 49 and 50 can be continuously regenerated in the main circuit.

<Excellent points of this embodiment>
According to the present embodiment, the piston 32-2 can be continuously reciprocated by the cooperation of the switching valve 30, the switching valve portion 32-3, and the spring 32-4 that are mechanically operated. Therefore, a high fluid pressure can be continuously generated without performing electrical control. This eliminates the need for conventional electric control and simplifies the configuration of the fluid pressure control circuit.

  Further, by providing the slow return valve 38 between the switching valve 30 and the switching valve portion 32-3, the switching valve 30 is switched when the tank pressure is supplied from the switching valve portion 32-3 to the switching valve 30. It progresses gradually by the restriction of the flow rate by the restriction. That is, the slow return valve 38 functions like a timer and can control the time (stroke time) for the piston 32-2 to return to the original position. Other configurations may be employed as long as the rate of change in fluid pressure applied to the switching valve 30 can be controlled.

  Since the high-pressure fluid generated by the pressure booster 32 is supplied by the reciprocation of the piston 32-2, pulsation due to the reciprocation of the piston 32-2 occurs, and if fluid pressure is supplied in this state, the device is adversely affected by the pulsation. There is a risk of getting out. According to this embodiment, the high-pressure fluid supplied from the pressure booster 32 can be always stored in the accumulators 49 and 50, so that a constant amount of high-pressure fluid can be always supplied.

  By providing the check valve 61 between the accumulators 49 and 50 and the main circuit, the system is divided into the main circuit side from the check valve 61 and the accumulators 49 and 50 side (upstream side) from the check valve 61. Can do. Therefore, even when the main circuit side has a high-pressure specification, each element on the accumulator 49, 50 side is made the minimum pressure specification necessary for regeneration to the supply destination of the high fluid pressure, so that the high-pressure fluid is not made unnecessary. Can be supplied.

  In this embodiment, the spring 32-4 is used as the urging unit. However, the urging unit is not limited to this, and may be appropriately adopted as long as it can generate a force for mechanically pushing back the piston. can do.

  Further, the switching valve portion 32-3 is configured to be movable integrally with the piston 32-2 as the second switching valve portion, so that the valve position can be switched, but interlocked with the movement of the piston 32-2. As long as the valve position can be switched, other configurations can be adopted as appropriate.

  Furthermore, in the present embodiment, the accumulator is provided with two accumulators as a pressure accumulator, but may be provided with three or more accumulators.

DESCRIPTION OF SYMBOLS 1 Drive mechanism 2 Main circuit hydraulic pump 3 Pilot circuit hydraulic pump (2nd fluid pressure supply part)
4 Switching valve 5 Cylinder 5
6 Hydraulic remote control valve 11 Tank (first fluid pressure supply part)
30 switching valve (first switching valve)
32 Pressure booster (pressure booster)
32-1 Case (Cylinder)
32-2 Piston 32-3 Switching valve section (second switching valve section)
32-4 Spring (Biasing part)
38 Variable slow return valve (throttle part)
49, 50 Accumulator (Accumulator)

Claims (6)

A first fluid pressure supply unit for supplying a first fluid pressure;
A second fluid pressure supply unit for supplying a second fluid pressure higher than the first fluid pressure;
A cylinder and a piston that reciprocates in the cylinder, and the second fluid pressure is loaded and the piston moves in the cylinder, thereby generating a fluid pressure higher than the second fluid pressure. A pressure increasing part;
The force acting on the piston by the load of the first fluid pressure is greater than the force acting on the piston by the load of the second fluid pressure in the direction opposite to the stroke direction of the piston at the time of the second fluid pressure load. A biasing portion that biases the piston with a small force;
A first switching valve portion that switches a valve position according to a change in a fluid pressure to be loaded, wherein the second fluid pressure supply portion is connected to the pressure increasing portion when the first fluid pressure is loaded; A first switching valve section that switches to connect the first fluid pressure supply section to the pressure increasing section when a second fluid pressure is applied;
A second switching valve portion whose valve position is switched by movement of the piston, wherein the first fluid pressure supply portion is connected to the first switching valve portion when the piston is at a stroke end position at the time of a second fluid pressure load. When the fluid pressure is applied from the second fluid pressure supply portion, the first switching valve portion is switched so that the fluid pressure is loaded from the second fluid pressure supply portion when the piston is at the stroke end position at the time of the first fluid pressure load. Two switching valves,
A fluid pressure control device comprising:   2. The fluid pressure control according to claim 1, wherein the first fluid pressure supply unit includes a throttle unit that regulates a flow rate of a fluid flowing through a flow path for applying a fluid pressure to the first switching valve unit. apparatus.   3. The pressure accumulating unit according to claim 1, further comprising a pressure accumulating unit that accumulates a fluid pressure higher than the second fluid pressure generated in the pressure increasing unit and that can supply the accumulated fluid pressure to the downstream side. Fluid pressure control device. The pressure accumulator is
A pressure accumulating means capable of accumulating fluid that has been increased to a fluid pressure higher than the second fluid pressure by the pressure increasing unit;
Pressure detecting means for detecting the pressure of the fluid accumulated in the pressure accumulating means;
A switching valve provided on the downstream side of the pressure accumulating means,
A controller for controlling the accumulation of the increased fluid in the pressure accumulating means and the supply / non-supply of the fluid accumulated in the pressure accumulating means to the downstream side by switching the switching valve;
The fluid pressure control device according to claim 3, further comprising:   The fluid pressure control device according to claim 4, wherein the pressure accumulating unit includes a plurality of the pressure accumulating means.   The fluid pressure control device according to claim 3, further comprising a check valve between the pressure accumulating unit and a supply destination of the fluid pressure accumulated in the pressure accumulating unit.

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