JP4155811B2 - Differential pressure adjustment valve - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a differential pressure regulating valve arranged for the purpose of stabilizing the system in a hydraulic control system, and more particularly to a differential pressure regulating valve arranged to compensate for the pressure of a variable displacement hydraulic pump.
[0002]
[Prior art]
Conventionally, in order to limit the hydraulic flow to the hydraulic control mechanism such as a hydraulic actuator and thereby obtain the stability of the control mechanism against the hydraulic fluctuation of the hydraulic pipeline, a differential pressure adjustment valve has been arranged in the hydraulic pipeline Various hydraulic control systems have been proposed.
[0003]
There has been proposed a hydraulic control system using a pair of check valves as an operation adjusting valve (see, for example, Patent Document 1). What was described in patent document 1 is equipped with the structure shown in FIG. Below, the action | operation adjustment valve described in patent document 1 is demonstrated using FIG.
[0004]
As shown in FIG. 12, a pair of check valves 87, 88 of opposite polarity are connected within the fluid line 80 and the load sensing / pressure compensation system 82. The check valve 88 maintains a flow rate of zero up to a predetermined pressure of the fluid with respect to the fluid flow from left to right in FIG. 12, and when the pressure exceeds the predetermined pressure, the valve element 90 causes the force of the spring 92 from the valve seat 91 by the fluid pressure. The fluid will flow from left to right. Similarly, with respect to the fluid flow from right to left in FIG. 12 of the valve 88, the flow rate is maintained at zero until a predetermined pressure of the fluid, and then the fluid flow is resisted against the force of the spring 93 as the fluid pressure increases. increase.
[0005]
FIG. 13 shows a pair of check valves 87, 88 as a two-way check valve assembly 100, showing the two check valves 87, 88 shown in FIG. 12 being integrated into a single assembly. Yes. The valve assembly 100 includes a cylindrical housing 102, and a pair of check valve elements 108 and 109 are disposed in the cavity 105 so as to be extendable and slidable.
[0006]
In FIG. 13, when fluid pressure is applied from left to right, the fluid passes through the end plug 103 and the passage 106 and enters the cavity 105. As the spindle 109 moves to the right against the force of the coil spring 115 under fluid pressure, the flow paths 112, 113 begin to overlap the shoulder 114, and the fluid flow through the flow path passes through the shoulder 114 and ends with the spindle 109. Enters the volume between the caps 110 and passes through the passages 111 and 107 and out of the valve assembly. Increasing the pressure of the fluid from left to right moves the spindle 109 further to the right, allowing greater fluid flow through the channels 112,113.
[0007]
Similarly, when fluid is applied from right to left in FIG. 13, the pressure applied to the end surface 116 of the cap 110 urges the valve element 108 and the spindle 109 to the left, and simultaneously moves the valve element 108 and the spindle 109 to the left. As the fluid pressure increases, the shoulder 114 enters the radial registry along with the channels 112, 113, the shoulder 114 begins to overlap the channels 112, 113, and the fluid flow through the channel flows through the shoulder 114; It passes through the passages 117, 118, and 119 and flows out from the passage 106 of the plug 104.
[0008]
As described above, the flow of the fluid is maintained in a zero state until the pressure of the fluid applied to the valve element 108 and the spindle 109 reaches a predetermined pressure, and when the fluid pressure becomes equal to or higher than the predetermined pressure, the shoulder 114 and the passages 112 and 113 are used. Thus, the fluid starts to flow and the flow rate is increased as the fluid pressure increases.
[0009]
However, in the device described in Patent Document 1, the fluid from the fluid pressure line 80 flows into the load sensing pressure compensation 82 only when the fluid pressure in the valve assembly 100 reaches a predetermined pressure. For this reason, in the first stage where fluid flows from the valve assembly 100 to the load sensing pressure compensation 82, the fluid increased to a predetermined pressure becomes an impact pressure and acts on the load sensing pressure compensation 82. In addition, the fluid flowing from the load sensing pressure compensation 82 to the fluid pressure line 80 flows out only when the pressure reaches a predetermined pressure, and the load sensing pressure compensation is performed when the fluid flows into and out of the load sensing pressure compensation 82. There will be significant fluctuations within 82.
[0010]
Further, since the fluid flows into the load sensing pressure compensation 82 only when the fluid pressure reaches the predetermined pressure, the pressure difference ΔP before and after the operation valve spool is increased._LSAnd the pressure difference acting on the LS valve of the pump do not consistently match. For this reason, there is a problem that the advantages of the load sensing system that can determine the work speed depending on the operation amount of the lever cannot be fully utilized.
[0011]
In addition, when a fluid in a low temperature state is used, the valve assembly 100 can set a predetermined pressure at which the fluid starts to flow with a spring in spite of using a fluid whose viscosity has increased due to a low temperature. The operation of the valve assembly 100 is the same as that at room temperature, and it cannot be said that the operation is changed by the oil temperature.
[0012]
[Patent Document 1]
Japanese Patent No. 3292474 (page 2, right column, line 49 to page 3, left column 16 line, page 3, right column, line 27 to page 4, right column, line 27, FIGS. 1 to 3)
[0013]
[Problems to be solved by the invention]
In the present invention, the above-mentioned conventional problems are solved, and in the differential pressure regulating valve arranged in the hydraulic control system, the hydraulic oil flowing out from the differential pressure regulating valve and the pressure oil flowing into the differential pressure regulating valve cause an abnormality in the hydraulic control system. The present invention provides a differential pressure regulating valve that can always maintain a control system in a stable state without being generated, and can improve the response and stability of the control system even when the pressure oil is at a low temperature. .
[0014]
[Means for Solving the Problems]
  The object of the present invention is achieved by the inventions described in claims 1 to 4.
  That is, the invention according to claim 1 isA sleeve and a spool that is slidably disposed in the sleeve, and a hydraulic space in the sleeve is divided into two oil chambers by the spool, and communicates between the two oil chambers.With variable aperturedidIn the differential pressure adjustment valve,
  The throttle that communicates between the two oil chambers depends on the magnitude of the pressure difference between the fixed throttle and the differential pressure regulating valve that acts on the spool when sliding in the left and right directions from the neutral position of the spool. A diaphragm that expands the opening area, and
  The differential pressure regulating valve isBased on the fixed aperturePredetermined apertureInA first mode to maintain;A diaphragm that communicates between the two oil chambers based on a diaphragm that expands the opening area.A second mode that expands, the first mode comprising:Acts on the spoolThe differential pressure before and after the differential pressure regulating valve is performed at a predetermined pressure or less, and the second mode isActs on the spoolThe differential pressure regulating valve is enlarged according to the differential pressure when the differential pressure is equal to or higher than a predetermined pressure.
[0015]
  In this invention, when the differential pressure before and after the differential pressure regulating valve is below a predetermined pressure,Even if you slide the spool in either direction,Pressure oil squeezed with a predetermined throttle can be discharged from the differential pressure adjustment valve, and when the differential pressure exceeds the predetermined pressure, the differential pressureIncrease the opening area according to the size ofBy increasing the aperturePassed through a diaphragm with a large aperture areaPressure oil can be discharged from the differential pressure regulating valve.
[0016]
  As a result, when responsiveness is required, such as when accelerating or decelerating a hydraulic actuator where the differential pressure before and after the differential pressure adjustment valve exceeds the specified pressure,Communicate between the two oil chambers in the sleeveWhen the throttle can be enlarged and stability is required, such as at steady speed when the differential pressure before and after the differential pressure adjustment valve is less than the specified pressure, Communicating between the two oil chambersThe diaphragm can be a fixed diaphragm.
[0017]
Also, the differential pressure ΔP before and after the operation valve spool_LSAnd the pressure difference acting on the LS valve of the pump steadily match. For this reason, the advantage of the load sensing system that can determine the working machine speed by the amount of operation of the lever can be fully utilized.
[0018]
  In addition, even when the differential pressure before and after the differential pressure adjustment valve is less than the predetermined pressure, the pressure oil can be discharged from the differential pressure adjustment valve.Between two oil chambers in the sleeveWhen changing the aperture,The hydraulic control system can be executed in a stable state without generating a fluctuating pressure or the like in the hydraulic control system.
[0019]
In addition to the matters of claim 1, the invention according to claim 2 of the present application is such that the first mode is performed when the intermediate pressure of the differential pressure before and after the differential pressure regulating valve is not more than a predetermined pressure, and the second mode is the differential pressure When the intermediate pressure is greater than or equal to a predetermined pressure, the differential pressure regulating valve is limited to the matters that are expanded according to the intermediate pressure of the differential pressure.
[0020]
  In the present invention, the intermediate pressure of the differential pressure before and after the differential pressure regulating valve is used to perform the first mode in which the predetermined throttle is maintained when the intermediate pressure is lower than the predetermined pressure, and when the intermediate pressure is higher than the predetermined pressure.Communicate between the two oil chambers in the sleeveAccording to the intermediate pressure in the second mode to expand the apertureCommunicate between the two oil chambersThe aperture is enlarged.Communicate between the two oil chambersSince the pressure for changing the throttle is the intermediate pressure, the differential pressure regulating valve can be operated at a low pressure, and the configuration of the differential pressure regulating valve can be made compact.
[0021]
  In addition to the matters of claim 1 or 2, the invention according to claim 3 of the present application is that the differential pressure regulating valve is not related to the differential pressure before and after the differential pressure regulating valve or the intermediate pressure of the differential pressure., Communicating between the two oil chambersA third mode that does not expand the throttle is further provided, and items that perform a mode appropriately combining the first mode, the second mode, and the third mode are limited in accordance with the flow direction of the hydraulic pressure that flows through the differential pressure regulating valve. In the differential pressure regulating valve.
[0022]
In this invention, according to the flow direction of the pressure oil flowing through the differential pressure regulating valve, the first mode and the second mode are performed on the flow in both directions, or the first mode is applied to the flow in one direction. The second mode is performed, and the third mode is performed for the flow in the reverse direction. This can be performed according to various demands in the hydraulic control system using the differential pressure regulating valve.
[0023]
In addition, the combination of the 1st to 3rd mode corresponding to a flow direction is not limited to the said description example, It can combine suitably as needed.
[0024]
  In addition to the matters described in any one of claims 1 to 3, the invention according to claim 4 of the present application corresponds to the flow direction of the hydraulic pressure flowing through the differential pressure regulating valve in the first mode and the second mode.Communicate between the two oil chambersThere is a differential pressure adjustment valve that limits the matters to change the adjustment amount of the throttle.
  In this invention, depending on the flow directionCommunicate between the two oil chambers in the sleeveSince the throttle can be adjusted, the throttle according to the request of the hydraulic control system in which the differential pressure adjusting valve is arranged can be obtained.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of the present invention will be specifically described below with reference to the accompanying drawings.
As an example to which the differential pressure regulating valve of the present invention is applied, it is possible to stabilize the hydraulic control system for the variable displacement pump and to improve the response when the response to the variable displacement pump is required. The case where it is arranged in the hydraulic control system for the mold pump will be described. However, the differential pressure regulating valve of the present invention is not limited to be installed in the hydraulic control system for the variable displacement pump, but can be placed in another hydraulic control system to ensure the stability of the hydraulic control system and control. When the responsiveness of the system is necessary, it can be applied to various hydraulic control systems in order to improve the responsiveness.
[0026]
As an embodiment in which the differential pressure regulating valve of the present invention is installed in a hydraulic control system, the flow rate of pressure oil from a variable displacement pump that is supplied to the hydraulic actuator in response to load fluctuations in the hydraulic actuator depends on the amount of operation by the operator. A hydraulic control system that performs control will be described as an example.
[0027]
As the displacement control of the variable displacement pump, a method of controlling the swash plate angle of the variable displacement hydraulic pump by detecting the state of the pressure oil discharged from the variable displacement hydraulic pump is performed. Control is also performed to keep the flow rate from the valve neutral circuit that is closed in the directional control valve to the tank constant according to the operation amount of the directional control valve operated by the operator.
[0028]
That is, the flow rate from the valve neutral circuit of the directional control valve in the neutral state to the tank is regarded as a surplus flow rate that cannot be used for work, and when the surplus flow rate is large, the discharge amount of the hydraulic pump is reduced and the surplus flow rate is reduced. When the flow rate is small, control is performed to keep the remaining flow rate constant by increasing the discharge amount of the hydraulic pump.
[0029]
As an explanation of an embodiment in which the differential pressure regulating valve of the present invention is applied to a hydraulic control system, the swash plate angle of the hydraulic pump is controlled by detecting the state of the pressure oil discharged from the hydraulic pump using FIG. The hydraulic control system will be described. In addition to the hydraulic control system described below, the differential pressure regulating valve according to the present invention is provided from the valve neutral circuit that closes in the same direction control valve to the tank according to the operation amount of the direction control valve operated by the operator. This is a differential pressure regulating valve that can be applied to both a hydraulic control system in which the flow rate is constant and other hydraulic control systems.
[0030]
First, assuming that the differential pressure regulating valves A and B are not arranged in FIG. 1, the hydraulic control system shown in FIG. 1 will be explained, and then the case where the differential pressure regulating valves A and B are arranged will be explained. .
[0031]
The variable displacement hydraulic pump 61 is rotationally driven by driving means 62 such as an engine, and the discharge flow rate Q corresponding to the discharge pressure Pp discharged from the variable displacement hydraulic pump 61 depends on the angle of the swash plate 63 and the variable displacement pressure oil pump. It can be determined by the number of revolutions of 61. The control of the swash plate 63 is controlled by the pressure at the operation valve outlet of the operation valve 64 provided between the variable displacement hydraulic pump 61 and the hydraulic actuator 65 (also serves as the load pressure of the hydraulic actuator) P._LSPressure difference ΔP and the discharge pressure Pp_LS(△ P_LS= Pp-P_LS) Is controlled to be constant.
[0032]
The discharge pressure Pp is taken out to the branch passage 71 branched from the pump passage 66, and is applied to one of the servo valve 68, the LS valve (load sensing valve) 69, and the PC valve (horsepower control valve) 70 for adjusting the angle of the swash plate 63. Each is introduced. In addition, the pressure P at the outlet of the operation valve 64_LSIs introduced into the LS valve 69. As the operation valve 64, a direction control valve or the like can be used.
[0033]
In the servo valve 68, the angle of the swash plate 63 is obtained by sliding the piston 68a in the left-right direction by the resultant force of the spring force and discharge pressure Pp acting from the left side of the drawing and the pressure in the chamber 68b on the right side of the servo valve 68. Adjustments are being made. In FIG. 1, when the piston 68a moves to the right, the angle of the swash plate 63 increases and the discharge capacity increases. Conversely, when the piston 68a moves to the left, the angle of the swash plate 63 decreases and the discharge capacity also decreases.
[0034]
The LS valve 69 has the discharge pressure Pp and the pressure P at the operation valve outlet._LSDifferential pressure ΔP_LS(△ P_LS= Pp-P_LS) Is controlled so that the angle of the swash plate 63 is constant, and the differential pressure ΔP_LSWhen the pressure becomes lower than the set pressure of the LS valve 69, the pressure of the chamber 68b on the right side in the servo valve 68 is decreased to move the piston 68a to the right, and the angle of the swash plate 63 is increased.
[0035]
Also, differential pressure ΔP_LSBecomes higher than the set pressure of the LS valve 69, the LS valve 69 is switched, and the discharge pressure Pp is reduced according to the opening area in the passage of the LS valve 69 and supplied to the chamber 68 b on the right side of the servo valve 68. By supplying the reduced discharge pressure Pp, the pressure in the right chamber 68b can be increased, and the piston 8a in the servo valve 68 is moved leftward to reduce the angle of the swash plate 63.
[0036]
The PC valve 70 controls the discharge flow rate from the variable displacement hydraulic pump 61 so as not to increase beyond a certain discharge flow rate Q corresponding to the discharge pressure Pp. Controls the horsepower so as not to exceed the engine horsepower of the drive means 62 driving the variable displacement hydraulic pump 61.
[0037]
That is, when the load on the hydraulic actuator 65 during work increases and the discharge pressure Pp from the variable displacement hydraulic pump 61 rises, control is performed to decrease the discharge flow rate Q from the variable displacement hydraulic pump 61, and conversely the discharge pressure When Pp decreases, control is performed to increase the discharge flow rate Q.
[0038]
When the discharge pressure Pp increases, the PC valve 70 switches to the right and supplies the discharge pressure Pp to the chamber 68b on the right side of the servo valve 68 to increase the chamber pressure on the right side of the servo valve 68. 68a is moved to the left. As a result, the pressure in the right chamber 68b can be adjusted to a pressure corresponding to the discharge pressure Pp at that time, and the maximum value of the angle that the swash plate 63 can take at this time is reduced. Thus, the differential pressure ΔP is obtained by operating the LS valve 69 described above in the state of each discharge pressure Pp._LSIn response to this change, the angle of the swash plate 63 can be adjusted within the range up to the maximum value of the angle described above.
[0039]
However, if the differential pressure regulating valve A is not disposed in the LS passage 67, the pulsation or buffering of the pressure in the LS passage 67 is generated by the operation of the hydraulic actuator 65, and the LS valve 69 and the servo valve 68 are generated. As a result, the stability of the hydraulic system is impaired and the stability of the vehicle body is impaired.
[0040]
Further, depending on the operating condition of the discharge hydraulic oil and the hydraulic actuator 65 from the variable displacement hydraulic pump 61, the pressure in the branch passage 71 may pulsate or buffer, and the response at the LS valve 69 and the PC valve 70 will be accelerated. Stability is impaired.
[0041]
In order not to cause these situations, the differential pressure regulating valves A and B of the present invention are arranged in the LS passage 67 and the branch passage 71. Although the differential pressure regulating valves A and B are disposed in the LS passage 67 and the branch passage 71, the differential pressure regulating valves do not necessarily have to be disposed in both passages. Thus, the required number of differential pressure regulating valves can be arranged.
[0042]
In order to explain the operation of the differential pressure regulating valves A and B, a preferred embodiment of the differential pressure regulating valve of the present invention will be described using the configuration of the differential pressure regulating valve shown in FIGS. 2 to 11 are circuit diagrams of the differential pressure regulating valve shown in the figures having the previous numbers. 2, 4, 6, 8, and 10, the inside of the fracture line of the spool 3 is shown as a displacement, and the notches 25 to 27 and the notches 50 and 51 do not generate a radial force. In addition, it is desirable to arrange the notches evenly on the circumference.
[0043]
FIG. 2 shows that the differential pressure adjusting valve is different from the differential pressure adjusting valve with respect to the bidirectional flow of hydraulic pressure (the hydraulic pressure flow from left to right and the hydraulic pressure flow from right to left in FIG. 2). It works as a fixed throttle until the differential pressure before and after the regulating valve reaches a predetermined pressure, and when the differential pressure exceeds the predetermined pressure, the throttle can be expanded according to the pressure of the differential pressure. The configuration is shown.
[0044]
The differential pressure regulating valve defines a hydraulic space oriented in the axial direction by a sleeve 1 and end plugs 2 and 2 ′ screwed to both ends, and the hydraulic space is oil in the end plugs 2 and 2 ′. A spool 3 communicating with the passages 10 and 11 and disposed in the sleeve 1 is slidably disposed in the same hydraulic space. The hydraulic space is divided into an oil chamber 12 and an oil chamber 13 by the sleeve 1.
[0045]
  The sleeve 1 is formed with an oil passage 14 and an oil passage 15 having one end opened to the oil chamber 12 or the oil chamber 13 in a non-communication state. The oil passage 14 communicates with a throttle 16 and a cut hole 18, and the oil passage A diaphragm 17 and a cut hole 19 communicate with 15.The restrictor 16 and the restrictor 17 are configured as a fixed restrictor that allows the oil chamber 12 and the oil chamber 13 to communicate with each other.Further, notches 25 to 27 are formed on the outer peripheral surface of the spool 3, the notch 26 communicates with the cut hole 18, and the notch 27 communicates with the cut hole 19.
  In addition, it is desirable that the notches 25 to 27 are arranged equally on the circumference so that a radial force is not generated.
[0046]
On the inner peripheral surface of the sleeve 1, annular oil passages 20 to 22 are formed apart from each other. Retainers 4 and 5 that are spring-biased by springs 6 and 7 that are in contact with the retainers 29 and 30 are provided so as to be in contact with the step formed on the inner peripheral surface of the sleeve 1. 5 is configured to abut against the step portion of the spool 3 and to slide with the spool 3 against the springs 6 and 7 by the pressing force of the spool 3. Also, filters 8 and 8 are provided at the connecting portion between the oil passage 10 and the oil chamber 12 and the connecting portion between the oil passage 11 and the oil chamber 13, respectively, and dust or the like enters the oil chambers 12 and 13. Is preventing.
[0047]
In FIG. 2, the left oil passage 10 in the differential pressure adjusting valve communicates with the LS passage 67a in FIG. 1, and the left oil passage 11 in the differential pressure adjustment valve communicates with the LS passage 67b in FIG. Here, the pressure oil pressure on the oil passage 10 side is P_LSVPressure, and the pressure oil pressure on the oil passage 11 side is P_LSPPressure.
[0048]
Next, the operation of the differential pressure adjusting valve will be described with reference to FIGS. In FIG. 1, the differential pressure adjusting valve B is also provided in the branch passage 71. However, in the following description of the operation of the differential pressure adjusting valve, the differential pressure adjusting valve B is provided in the branch passage 71. The explanation will be made assuming that it is not.
[0049]
When an operating lever (not shown) for operating the hydraulic actuator 65 is operated and LS pressure is introduced from the operating valve 64 into the oil passage 67a, P_LSVThe pressure rises and P on the oil passage 11 side_LSPA differential pressure is generated between the pressure. Due to this differential pressure, the spool 3 is pushed rightward from the neutral position in FIG. 2 and moves to a position where it comes into contact with the retainer 5.
[0050]
Until the spool 3 comes into contact with the retainer 5 from the neutral position, the pressure oil that has entered from the oil passage 10 passes through the oil chamber 12 and enters the oil passage 14, while pressing the spool 3 in the right direction, passing through the throttle 16, and the sleeve 1. Passes through the oil passage 21 formed on the outer periphery of the spool 3, passes through the oil passage 22 formed on the sleeve 1, passes through the oil passage 15, the oil chamber 13, and the oil passage 11 from the cut hole 19. P outside the pressure regulating valve_LSPIt flows out as pressure and passes through the LS passage 67 b and is guided to the LS valve 69.
[0051]
LS valve 69 is P_LSPThe servo valve 8 is controlled according to the pressure and adjusted so that the angle of the swash plate 63 is increased. P_LSVPressure and P_LSPWhen the pressure difference from the pressure is large, that is, when the operation amount of the operation lever of the hydraulic actuator 65 is greatly changed and the capacity of the variable displacement pump 61 is to be greatly changed, the differential pressure due to the throttle 16 in the spool 3 is large. Thus, the force for pressing the spool 3 in the right direction in FIG. 2 is increased.
[0052]
  When the force that presses the spool 3 becomes larger than the spring force of the spring 7, the spool 3 further moves to the right in FIG. 2 while pushing the retainer 5. When the spool 3 pushes the retainer 5 and moves in the right direction, the pressure oil flowing from the oil passage 14 in the spool 3 through the cut hole 18 to the notch 26 in addition to the passage by the throttle 16 is The passage led to the oil passage 21 formed on the surface is opened.That is, the oil passage is opened according to the opening area between the notch 26 and the oil passage 21.
[0053]
The pressure oil guided to the oil passage through the newly opened passage is, together with the pressure oil from the throttle 16, the notch 25 formed on the outer peripheral surface of the spool 3 from the oil passage 21 and the oil passage 22 formed in the sleeve 1. Through the oil passage 15, the oil chamber 13, and the oil passage 11 from the cut hole 19 to the outside of the differential pressure regulating valve._LSPIt flows out as pressure and passes through the LS passage 67 b and is guided to the LS valve 69.
[0054]
Therefore, the LS pressure on the operation valve 64 side, that is, P_LSVThe pressure is quickly transmitted to the LS valve 69, and the variable displacement pump 61 can quickly respond to the operation amount of the operation lever of the hydraulic actuator 65.
[0055]
When the discharge flow rate of the variable displacement pump 61 catches up with the required flow rate of the hydraulic actuator 65 by the operation lever of the hydraulic actuator 65, the pressure in the branch passage 71 is equal to the differential pressure across the spool meter-in opening 4a of the operation valve 64. To rise. Due to the pressure increase in the branch passage 71, the spool of the LS valve 69 is pushed rightward, and the pressure oil corresponding to the volume moved by the spool flows into the LS passage 67b._LSPIncrease pressure.
[0056]
P_LSPAs the pressure increases, the pressure in the right oil chamber 13 in the differential pressure regulating valve increases, and the spool 3 is moved to the left in FIG. P_LSVPressure and P_LSPWhen the pressure difference from the pressure is equal to or lower than the predetermined pressure, the pressure oil that has entered from the oil passage 11 passes through the oil chamber 15, passes through the throttle 17, and moves to the sleeve 1 while moving the spool 3 in the left direction. It passes through the formed oil passage 21, passes through the oil passage 20 formed in the sleeve 1 from the notch 25 formed on the outer peripheral surface of the spool 3, and passes through the oil passage 14, the oil chamber 12, and the oil passage 10 from the cut hole 18. It flows out of the regulating valve.
[0057]
  P_LSPPressure and P_LSVWhen the pressure difference from the pressure becomes larger than a predetermined pressure, that is, when the force pressing the spool 3 becomes larger than the spring force of the spring 6, the spool 3 further moves leftward in FIG. When the spool 3 moves to the left by pushing the retainer 4, the pressure oil flowing from the oil passage 15 in the spool 3 through the cut hole 19 to the notch 27 in addition to the passage by the throttle 17 is The passage led to the oil passage 21 formed on the surface is opened.That is, the oil passage is opened according to the opening area between the notch 27 and the oil passage 21.
[0058]
The pressure oil guided to the oil passage through the newly opened passage is, together with the pressure oil from the throttle 17, the notch 25 formed on the outer peripheral surface of the spool 3 from the oil passage 21 and the oil passage 20 formed in the sleeve 1. Through the cut hole 18 and through the oil passage 14, the oil chamber 12, and the oil passage 10 to the outside of the differential pressure regulating valve.
[0059]
Here, a case where the discharge flow rate of the variable displacement pump 61 is trying to catch up with the required flow rate of the hydraulic actuator 65 by the operating lever for operating the hydraulic actuator 65 is shown. The pressure increase corresponding to the differential pressure across the spool meter-in opening 64a becomes smaller as the opening area of the LS valve 69 moves toward the balance position, and as a result, the movement of the swash plate 63 of the variable displacement pump 61 becomes gentle and constant. Will head to the position. For this reason, the differential pressure across the spool meter-in opening 64a gently heads toward the set value._LSPPressure and P_LSVThe pressure difference from the pressure is reduced, and the spool 3 is in contact with the retainer 4. As a result, the differential pressure adjustment valve can function as a throttle, the fluctuation of the LS pressure is suppressed, and the pressure oil discharged from the variable displacement pump 61 is set by the operation lever of the hydraulic actuator 65 in a stable state. The target flow rate can be settled.
[0060]
As you can see from this, P_LSVPressure and P_LSPWhen the differential pressure with respect to the pressure is less than or equal to a predetermined pressure, the spool 3 moves until it abuts against the retainer 5 or the retainer 4 so that the diameter of the throttle 16 as the differential pressure adjusting valve functions as a predetermined diameter, that is, a fixed throttle. it can. P_LSVPressure and P_LSPWhen the pressure difference from the pressure exceeds a predetermined pressure, a new passage is opened in addition to the throttle 16 or the throttle 17, and the newly opened passage is P_LSVPressure and P_LSPThe pressure can be adjusted according to the magnitude of the pressure difference.
[0061]
As a result, when responsiveness to the operation lever is required, such as during acceleration / deceleration of the hydraulic actuator, the responsiveness can be improved by enlarging the throttle of the differential pressure adjustment valve, and the hydraulic actuator can be stably operated at a steady speed. When operating, the throttle of the differential pressure regulating valve can be reduced. In addition, when the differential pressure adjustment valve front-rear differential pressure is equal to or lower than the predetermined pressure, the throttle state is maintained, and when the front-rear differential pressure exceeds the predetermined pressure, the throttle is expanded according to the front-rear differential pressure of the differential pressure adjustment valve. be able to.
[0062]
FIG. 3 shows a hydraulic circuit of the differential pressure regulating valve shown in FIG.
In the description of FIG. 2, the description of the differential pressure adjustment valve disposed in the branch passage 71 is omitted, but by arranging the differential pressure adjustment valve B in the branch passage 71, the differential pressure across the spool meter-in opening 4 a is determined. As a state in which the fluctuation of the pressure oil flowing into the branch passage 71 is suppressed, it can be introduced to the LS valve 69 and the PS valve 10 as a control pressure.
[0063]
In the above embodiment, the differential pressure adjusting valve is used to construct a stable hydraulic control system in response to fluctuations in the LS pressure and fluctuations in the pressure oil flowing into the branch passage 71 due to the differential pressure across the spool meter-in opening 4a. However, when the differential pressure regulating valve of the present invention is used, it is possible to prevent a decrease in responsiveness and stability at low temperatures.
[0064]
That is, the pressure oil has the property that the viscosity increases as the temperature of the pressure oil decreases. Even if the viscosity is increased, if the flow rate of the pressure oil flowing through the throttle is the same if it is an ideal throttle, the differential pressure across the throttle is the same value as before the viscosity increased. However, in an actual diaphragm, the differential pressure before and after the temperature changes depending on the temperature. That is, when the temperature of the pressure oil decreases, the differential pressure across the throttle increases even at the same flow rate.
[0065]
When the differential pressure adjusting valve of the present invention is used, the pressure difference between the front and rear of the throttle increases as the temperature of the pressure oil decreases. As a result, the spool moves in the direction of enlarging the throttle and increases the flow rate. For this reason, the responsiveness with respect to an operation lever can be improved. In general, responsiveness decreases at various parts at low temperatures, but by using the differential pressure regulating valve of the present invention, it becomes possible to compensate the responsiveness of the entire system as well as the responsiveness at room temperature. .
[0066]
By using the differential pressure regulating valve of the present invention, when the pressure oil flowing in the pipe line is low temperature, the throttle at the differential pressure regulating valve is increased, and the throttle is reduced as the pressure oil temperature rises. Can do.
[0067]
Hereinafter, another embodiment of the differential pressure adjusting valve of the present invention will be described using the hydraulic control system of FIG. 1, but as described above, the differential pressure adjusting valve in other embodiments described below is also a pressure control system. It can be used in a hydraulic control system as a differential pressure regulating valve that compensates for responsiveness to oil temperature.
[0068]
The differential pressure regulating valve shown in FIG. 4 and its circuit diagram shown in FIG. 5 eliminates the spring 6 and the retainer 4 disposed on the left side in the differential pressure regulating valve shown in FIGS. 2 and 3, and the retainer 29 is replaced with a thick retainer 31. The other structure has the same structure as the differential pressure regulating valve shown in FIGS. Therefore, the same members as those of the differential pressure adjusting valve in FIG.
[0069]
In FIG. 4, P_LSVPressure and P_LSPThe pressure oil introduced from the oil passage 10 by the pressure difference from the pressure has the same action as the pressure difference adjusting valve in FIG. That is, when the differential pressure is equal to or lower than the predetermined pressure, the pressure oil that has passed through the throttle 16 flows into the oil passage 11, and when the differential pressure exceeds the predetermined pressure, the pressure oil introduced from the flow path 10 passes through the throttle 16. And a new passage that flows out from the oil passage 21 through the notch 26 from the cut hole 18 and can flow out into the oil passage 11.
[0070]
In the flow from right to left in FIG._LSPPressure is P_LSVWhen the pressure becomes higher than the pressure, the end of the spool 3 comes into contact with the thick retainer 31 and the leftward movement is restricted, and the pressure oil introduced from the oil passage 11 passes through the oil passage 15 from the oil chamber 13. From the throttle 17, the oil passage 21 passes through the notch 25, flows from the oil passage 20 through the cut hole 18, and flows from the oil passage 14 to the oil passage 10.
[0071]
This allows P_LSVPressure is P_LSPWhen the pressure is higher than P_LSVPressure and P_LSPDepending on whether the pressure difference between the pressure and P is less than or equal to a predetermined pressure, the differential pressure adjustment valve functions as a valve that can change the throttle from a fixed throttle._LSVPressure is P_LSPWhen the pressure is lower than the pressure, the differential pressure adjusting valve functions as a fixed throttle.
[0072]
The differential pressure regulating valve shown in FIG. 6 and FIG. 7 which is a circuit diagram thereof eliminates the throttle 17 disposed on the right side in the differential pressure regulating valve shown in FIGS. 2 and 3, and the length of the notch 25 in the axial direction is reduced. The other configuration is the same as the differential pressure regulating valve shown in FIGS. Therefore, the same members as those of the differential pressure adjusting valve in FIG.
[0073]
In FIG. 6, P_LSVPressure and P_LSPThe pressure oil introduced from the oil passage 10 by the pressure difference from the pressure has the same action as the pressure difference adjusting valve in FIG.
In the flow from right to left in FIG._LSPPressure is P_LSVWhen the pressure becomes higher, the pressure oil introduced from the oil passage 11 passes through the oil passage 15 from the oil chamber 13, passes through the oil passage 21 and the notch 25 from the cut hole 19, and passes through the cut hole 18 from the oil passage 20. Then, the oil flows from the oil passage 14 to the oil passage 10 through the oil chamber 12.
[0074]
This allows P_LSVPressure is P_LSPWhen the pressure is higher than the pressure, the differential pressure adjusting valve can be changed from the fixed throttle state to the throttle state depending on the magnitude of the differential pressure between the two. P_LSVPressure is P_LSPWhen the pressure is lower than the pressure, the differential pressure regulating valve functions as if it is in a fully-through state.
[0075]
  The differential pressure regulating valve shown in FIG. 8 and its circuit diagram shown in FIG. 8 is closed so that the left and right oil passages 14 and 15 do not communicate with the oil chambers 12 and 13, respectively, in the differential pressure regulating valve shown in FIGS. Lids 38 and 39 are respectively attached to the end portions of the oil passages 14 and 15 which are open on the oil chambers 12 and 13 side in FIG. Further, the notch 26 and the notch 27 are formed to have long notches so as to communicate with the oil chamber 12 and the oil chamber 13, respectively, and through the throttles 35 and 36 formed in place of the cut holes 18 and 19. The oil passages 14 and 15 communicate with the oil chambers 12 and 13, respectively.The throttles 16 and 17 and the throttles 35 and 36 are configured as fixed throttles that allow the oil chamber 12 and the oil chamber 13 to communicate with each other.Other configurations are the same as those of the differential pressure regulating valve shown in FIGS. Therefore, the same members as those of the differential pressure adjusting valve in FIG.
[0076]
In FIG. 8, P_LSVPressure and P_LSPThe pressure oil introduced from the oil passage 10 due to the pressure difference with the pressure is substantially the same except that the pressure difference adjusting valve in FIG. Play.
That is, P_LSVP due to pressure increase_LSVPressure is P_LSPWhen the pressure exceeds the pressure, the pressure in the left oil chamber 12 in the differential pressure regulating valve rises, and the pressure receiving area including the lid 38 of the spool 3 receives the pressure oil pressure in the oil chamber 12 so that the spool 3 8 moves to the right in FIG. While moving the spool 3 in the right direction, the pressure oil that has entered from the oil passage 10 is introduced from the oil chamber 12 through the notch 26 and through the throttle 35 into the oil passage 14. The oil is introduced into the oil passage 15 from the oil passage 21 through the restriction 17 through the restriction 16 formed in the oil passage 14. The oil flows from the oil passage 15 through the throttle 36, flows from the notch 27 through the oil chamber 13, and flows out from the oil passage 11 to the outside of the differential pressure regulating valve.
[0077]
P_LSVPressure and P_LSPWhen the pressure difference from the pressure increases, that is, when the force pressing the spool 3 becomes larger than the spring force of the spring 7, the spool 3 further moves to the right in FIG. 8 while pushing the retainer 5. When the spool 3 pushes the retainer 5 and moves in the right direction, the notch 26 communicates with the oil passage 21 and flows from the notch 25 to the oil passage 22, and a new passage flowing from the notch 27 to the oil chamber 13 is opened. At this time, the opening area of the notch 26 and the oil passage 21 and the opening area of the notch 25 and the oil passage 22 are applied to the spool 3 in the oil chamber 12._LSVPressure and P_LSPIt becomes an opening area according to the magnitude of the pressure difference from the pressure.
[0078]
In the flow from right to left in FIG. 8, that is, P_LSPPressure is P_LSVP when the pressure becomes higher_LSPPressure and P_LSVWhen the pressure difference from the pressure is equal to or lower than the predetermined pressure, the spool 3 moves to the left until it contacts the retainer 4. At this time, the pressure oil that has entered from the oil passage 11 is introduced from the oil chamber 13 through the notch 27 and through the throttle 36 into the oil passage 15. The oil is introduced into the oil passage 14 through the restriction 17 formed in the oil passage 15 and from the oil passage 21 through the restriction 16.
[0079]
The oil passage 14 passes through the throttle 35, the notch 26 passes through the oil chamber 12, and flows out from the oil passage 10 to the outside of the differential pressure regulating valve. By changing the diameters of the throttles 35, 16, 17, and 36 arranged in series in four stages, the diameter as the fixed throttle can be arbitrarily and finely adjusted.
[0080]
P_LSPPressure and P_LSVWhen the pressure difference from the pressure becomes larger than a predetermined pressure, that is, when the force pressing the spool 3 becomes larger than the spring force of the spring 6, the spool 3 further moves to the left in FIG. When the spool 3 moves to the left by pushing the retainer 4, the notch 27 communicates with the oil passage 21, flows from the notch 25 to the oil passage 20, and opens a new passage that flows into the oil chamber 12 through the notch 26. To do. At this time, the opening area between the notch 27 and the oil passage 21 and the opening area between the notch 25 and the oil passage 20 act on the spool 3 in the oil chamber 13._LSPPressure and P_LSVIt becomes an opening area according to the magnitude of the pressure difference from the pressure.
[0081]
This allows P_LSVPressure and P_LSPWhen the differential pressure with respect to the pressure is less than or equal to a predetermined pressure, a four-stage series throttle can be performed, and when the differential pressure becomes higher than the predetermined pressure, the throttle can be changed to an opening area corresponding to the differential pressure. become.
[0082]
FIG. 10 and FIG. 11 which is a circuit diagram thereof are configured as a cartridge type differential pressure regulating valve in which the differential pressure regulating valve can be inserted and installed in the hydraulic equipment. , P_LSVPressure and P_LSPThe spool 3 is moved by an intermediate pressure that is a differential pressure from the pressure. That is, P_LSVPressure and P_LSPThe spool 3 starts to move when a pressure difference of 1/2 or more of the spring force in the springs 6 and 7 shown in FIG.
[0083]
The configuration of the differential pressure adjusting valve shown in FIG. 10 will be described. The differential pressure regulating valve is inserted into a housing 55 such as a hydraulic device, and a hydraulic space oriented in the axial direction is defined by the sleeve 1, the end plug 52 disposed at one end, and the housing 55. A spool 3 is slidably disposed in the sleeve 1. The oil passage 10 communicated with the LS passage 67a in FIG. 1 communicates with the oil passage 44 formed in the outer peripheral portion of the sleeve 1, and the oil passage 11 communicated with the LS passage 67b and the oil passage 45 formed in the outer peripheral portion of the sleeve 1. Communicate. The oil passage 44 communicates with a notch 48 formed in the inner peripheral surface of the sleeve 1 by a cut hole 46 formed in the sleeve 1, and the oil passage 45 is formed in the inner peripheral surface of the sleeve 1 by a cut hole 47 formed in the sleeve 1. Communicated with the cutout 49.
[0084]
  In the spool 3, a throttle 40 is formed between the oil passage 14 and the oil passage 15, and both the passages 14 and 15 are communicated with each other through the throttle 40.The throttle 40 is configured as a fixed throttle that allows the oil chamber 12 and the oil chamber 13 to communicate with each other.The ends of the oil passages 14 and 15 on the side of the oil chambers 12 and 13 are open to the oil chambers 12 and 13, but the ends of the oil passages 14 and 15 on the side of the oil chambers 12 and 13 are closed with a lid or the like. You can also The oil passage 14 communicates with a notch 50 formed on the outer periphery of the spool 3 via the cut hole 18, and the oil passage 15 communicates with a notch 51 formed on the outer periphery of the spool 3 via the throttle 41. Note that it is desirable that the notches 50 and 51 are arranged equally on the circumference so as not to generate a radial force.
  Further, a cut hole 42 is formed in the oil passage 15 and is closed by the inner peripheral surface of the sleeve 1 during the movement from the neutral position of the spool 3 to the right, and the movement from the neutral position of the spool 3 to the left. Are formed at positions communicating with the oil passage 49.
[0085]
Retainers 4 and 5 that are spring-biased by springs 6 and 7 are provided so as to be in contact with the step formed on the inner peripheral surface of the sleeve 1, and the retainers 4 and 5 are in contact with the step of the spool 3, The spool 3 is configured to be able to slide with the spool 3 against the springs 6 and 7 by the pressing force of the spool 3. In FIG. 10, filters (not shown) are provided between the oil passage 10 and the oil passage 44 and between the oil passage 11 and the oil passage 45, respectively, to prevent dust and the like from entering the oil passages 44 and 45. It is out.
[0086]
10, the left oil passage 10 in the differential pressure adjusting valve communicates with the LS passage 67a in FIG. 1, and the left oil passage 11 in the differential pressure adjustment valve communicates with the LS passage 67b in FIG. Here, the pressure oil pressure on the oil passage 10 side is P_LSVPressure, and the pressure oil pressure on the oil passage 11 side is P_LSPPressure.
[0087]
In FIG. 10, P_LSVThe pressure increases and P on the oil passage 11 side_LSPA differential pressure is generated between the pressure. Due to this differential pressure, the spool 3 is pushed rightward from the neutral position in FIG. 10 and moved to a position where it comes into contact with the retainer 5.
[0088]
Until the spool 3 comes into contact with the retainer 5 from the neutral position, the pressure oil that has entered from the oil passage 10 passes through the oil passage 44 and enters the oil passage 14 through the cut hole 46, while pressing the spool 3 in the right direction, while reducing the throttle 40 And is introduced into the oil passage 15. The pressure oil that has entered the oil passage 15 passes through the restrictor 41, passes through the cutout 47 from the notch 51 and the oil passage 49, passes through the oil passage 45 through the oil passage 11, and is outside the differential pressure adjusting valve._LSPIt flows out as pressure and passes through the LS passage 67 b and is guided to the LS valve 69.
[0089]
P_LSVPressure and P_LSPWhen the pressure difference from the pressure exceeds a predetermined pressure, when the force pressing the spool 3 is greater than the spring force of the spring 7, the spool 3 further moves to the right in FIG. 2 while pushing the retainer 5. When the spool 3 pushes the retainer 5 and moves in the right direction, the pressurized oil that has entered from the oil passage 10 passes through the oil passage 48 from the cut hole 46, and a new passage that is introduced from the notch 50 to the oil passage 49 is opened. The opening area of the notch 50 and the oil passage 49 is P_LSVPressure and P_LSPIt becomes an opening area according to the intermediate pressure of the differential pressure from the pressure.
[0090]
The pressure oil introduced into the oil passage 49 through the newly opened passage passes through the cut hole 47, passes through the oil passage 45, passes through the oil passage 11, and then passes to the outside of the differential pressure adjusting valve._LSPIt flows out as pressure and passes through the LS passage 67 b and is guided to the LS valve 69.
[0091]
Conversely, when pressure oil flows from right to left in FIG. 10, that is, P_LSPPressure is P_LSVWhen the pressure becomes higher than the pressure, the spool 3 is pushed in the left direction in FIG.
[0092]
Until the spool 3 comes into contact with the retainer 4, the pressure oil that has entered from the oil passage 11 passes through the oil passage 45, enters the oil passage 49 through the cut hole 47, and is introduced into the oil passage 15 through the cut holes 42 and 41. . The pressure oil that has entered the oil passage 15 is introduced into the oil passage 14 through the throttle 40, passes through the cut hole 18, passes through the notch 50, passes through the oil passage 48, passes through the cut hole 46, and passes from the oil passage 44 to the oil passage 10. Led.
[0093]
P_LSPPressure and P_LSVWhen the pressure difference from the pressure exceeds a predetermined pressure, when the force pressing the spool 3 is greater than the spring force of the spring 6, the spool 3 further moves to the left in FIG. When the spool 3 moves to the left by pushing the retainer 4, the pressurized oil that has entered from the oil passage 11 passes through the oil passage 45, enters the oil passage 49 through the cut hole 47, and is introduced into the oil passage 48 from the notch 51. The passage opens.
[0094]
The pressure oil guided to the oil passage 48 through the newly opened passage is guided to the outside of the differential pressure adjusting valve through the cut hole 46 and from the oil passage 44 through the oil passage 10.
At this time, the opening area of the notch 51 and the oil passage 48 is P_LSPPressure and P_LSVIt becomes an opening area according to the intermediate pressure of the differential pressure from the pressure.
[0095]
In the differential pressure adjusting valve shown in FIG. 10, the pressure of the pressure oil that slides the spool 3 is the differential pressure across the throttle 40. For example, P_LSVPressure is 30kg / cm², P_LSPPressure is 0kg / cm²When the diameter of the throttle 40 and the throttle 41 is adjusted, the oil passage 14 has 30 kg / cm.²Is applied, and the oil passage 15 is 15 kg / cm.²The cutout 51 is 0 kg / cm²The pressure can be configured to be applied.
[0096]
At this time, the spool 3 is 15 kg / cm.²Pressure, ie, P_LSVPressure and P_LSPSince only an intermediate pressure is applied, the spring force of the spring 7 can be reduced, that is, a spring having half the spring force of the spring 7 shown in FIG. 2 can be used. Thereby, the configuration of the differential pressure regulating valve can be made compact.
[0097]
The intermediate pressure for sliding the spool 3 can be set to a desired intermediate pressure by adjusting the diameters of the throttle 40 and the throttle 41.
[0098]
As mentioned above, although various embodiment of this-application differential pressure regulation valve was described, the differential-pressure regulation valve of this invention is not limited to the above-mentioned structure, The range of the structure which satisfy | fills the matter described in Claims 1 thru | or 4 of this application An appropriate configuration can be adopted.
[0099]
Further, the fixed throttle in the differential pressure regulating valve of the present application can be changed as appropriate according to the requirements of the place where the differential pressure regulating valve is used.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example in which a differential pressure regulating valve is applied to a hydraulic control system.
FIG. 2 is a configuration diagram showing an embodiment of a differential pressure regulating valve.
FIG. 3 is a circuit diagram of the differential pressure regulating valve of FIG. 2;
FIG. 4 is a configuration diagram showing a second embodiment of a differential pressure regulating valve.
5 is a circuit diagram of the differential pressure regulating valve in FIG. 4;
FIG. 6 is a block diagram showing a third embodiment of the differential pressure regulating valve.
7 is a circuit diagram of the differential pressure regulating valve of FIG. 6. FIG.
FIG. 8 is a configuration diagram showing a fourth embodiment of a differential pressure regulating valve.
9 is a circuit diagram of the differential pressure regulating valve of FIG. 8. FIG.
FIG. 10 is a configuration diagram showing a fifth embodiment of a differential pressure regulating valve.
11 is a circuit diagram of the differential pressure regulating valve of FIG.
FIG. 12 is a hydraulic control system diagram showing a conventional example.
13 is a view showing a differential pressure regulating valve in the conventional example of FIG.
[Explanation of symbols]
1 sleeve
2, 2 'end plug
3 Spool
4, 5 Retainer
6, 7 Spring
8 Filter
10, 11 Oilway
12, 13 Oil chamber
14, 15 Oil passage
16, 17 aperture
18, 19 Cut hole
20-22 Oilway
25-27 cutout
29, 30 Retainer
31, 32 Retainer
35, 36 aperture
38, 39 lid
40, 41 aperture
42 Cut hole
44, 45 Oil passage
46, 47 Cut hole
48, 49 Oilway
50, 51 Notch
52 End plug
53 Retainer
54 Mounting nut
55 Housing
61 Variable displacement hydraulic pump
62 Driving means
63 Swashplate
64 Operation valve
64a Spool meter-in opening
65 Hydraulic actuator
66 Pump passage
67, 67a, 67b LS passage
68 Servo valve
68a piston
68b room
69 LS valve
70 PC valve
71 branch passage
72 tanks
80 Fluid lines
81 Valve system
82 Load sensing / pressure compensation system
83 Hydraulic pump
84 Swashplate
85 tanks
87, 88 Check valve
90 Valve elements
91 Valve seat
92, 93 Spring
100 Check valve assembly
102 Housing
103, 104 End plug
105 cavity
106, 107 passage
108 Valve elements
109 spindle
110 cap
111 passage
112, 113 flow path
114 Shoulder
115 Coil spring
116 End face
117-119 passage
A, B Differential pressure adjustment valve
Pp discharge pressure
Q Discharge flow rate
P_LS           Pressure at the operation valve outlet
△ P Pp and P_LSDifferential pressure with
P_CB           Dynamic pressure outlet pressure
P_CA           Outlet port pressure

Claims (4)

A sleeve and a spool that is slidably disposed in the sleeve, and the hydraulic space in the sleeve is divided into two oil chambers by the spool, and the throttle for communicating between the two oil chambers is variable. The differential pressure regulating valve
The throttle that communicates between the two oil chambers depends on the magnitude of the pressure difference between the fixed throttle and the differential pressure regulating valve that acts on the spool when sliding in the left and right directions from the neutral position of the spool. A diaphragm that expands the opening area, and
Second mode in which the differential pressure regulating valve, to expand the first mode to maintain a predetermined aperture, the aperture communicating between the two oil chambers on the basis of the aperture to expand the aperture area on the basis of the fixed throttle And
The first mode is performed when the differential pressure before and after the differential pressure regulating valve acting on the spool is a predetermined pressure or less,
The differential pressure regulating valve according to claim 2, wherein the second mode is expanded according to the differential pressure when the differential pressure acting on the spool is equal to or higher than a predetermined pressure. The first mode is performed when the intermediate pressure of the differential pressure before and after the differential pressure regulating valve is not more than a predetermined pressure,
2. The differential pressure regulating valve according to claim 1, wherein the second mode is expanded according to the intermediate pressure of the differential pressure when the intermediate pressure of the differential pressure is equal to or higher than a predetermined pressure. The differential pressure adjusting valve further includes a third mode in which expansion of a throttle for communicating between the two oil chambers is not performed regardless of a differential pressure before and after the differential pressure adjusting valve or an intermediate pressure of the differential pressure,
3. The differential pressure according to claim 1, wherein a mode in which the first mode, the second mode, and the third mode are appropriately combined is performed in accordance with a flow direction of the hydraulic pressure that flows through the differential pressure regulating valve. tuning valve. The throttle adjustment amount for communicating between the two oil chambers in the first mode and the second mode is changed in accordance with the flow direction of the hydraulic pressure flowing through the differential pressure regulating valve. 4. The differential pressure regulating valve according to any one of 3 above.

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