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CN111473011B - Flow control valve and operating machinery - Google Patents

Flow control valve and operating machinery Download PDF

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Publication number
CN111473011B
CN111473011B CN202010073712.1A CN202010073712A CN111473011B CN 111473011 B CN111473011 B CN 111473011B CN 202010073712 A CN202010073712 A CN 202010073712A CN 111473011 B CN111473011 B CN 111473011B
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CN
China
Prior art keywords
valve
valve member
housing
control valve
throttle
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202010073712.1A
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Chinese (zh)
Other versions
CN111473011A (en
Inventor
岩崎仁
后藤敬介
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Nabtesco Corp
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Nabtesco Corp
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Publication date
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Publication of CN111473011A publication Critical patent/CN111473011A/en
Application granted granted Critical
Publication of CN111473011B publication Critical patent/CN111473011B/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
    • F15B13/021—Valves for interconnecting the fluid chambers of an actuator
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
    • F16K11/00—Multiple-way valves, e.g. mixing valves; Pipe fittings incorporating such valves
    • F16K11/02—Multiple-way valves, e.g. mixing valves; Pipe fittings incorporating such valves with all movable sealing faces moving as one unit
    • F16K11/04—Multiple-way valves, e.g. mixing valves; Pipe fittings incorporating such valves with all movable sealing faces moving as one unit comprising only lift valves
    • F16K11/044—Multiple-way valves, e.g. mixing valves; Pipe fittings incorporating such valves with all movable sealing faces moving as one unit comprising only lift valves with movable valve members positioned between valve seats
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/08—Servomotor systems without provision for follow-up action; Circuits therefor with only one servomotor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
    • F15B13/04—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
    • F15B21/001—Servomotor systems with fluidic control
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
    • F16K27/00—Construction of housing; Use of materials therefor
    • F16K27/02—Construction of housing; Use of materials therefor of lift valves
    • F16K27/0263—Construction of housing; Use of materials therefor of lift valves multiple way valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or valve

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Details Of Valves (AREA)
  • Valve Housings (AREA)
  • Sliding Valves (AREA)

Abstract

本发明提供流量控制阀和作业机械。防止在流量控制阀中产生响应延迟。另外，削减变更流量控制阀的功能之际的更换零部件个数。流量控制阀(20)具备壳体(30)和阀构造体(40)，壳体具有两个端口(30a、30b)和内部空间(S)，内部空间是具有台阶部(33、38)的形状，与两个端口(30a、30b)连接，阀构造体具有：节流部(62)，其设置于将两个端口(30a、30b)之间连结的流路；接触部(53)，其具有与移动方向不平行的面(53a)，通过与台阶部(33、38)接触，能够阻断另一流路；按压构件(70)，其以使接触部(53)能够与壳体(30)的台阶部(33、38)接触的方式按压该接触部，该阀构造体(40)以能够移动的方式收纳于壳体(30)的内部空间(S)内。

The present invention provides a flow control valve and an operating machine, which prevents response delay in the flow control valve and reduces the number of parts to be replaced when changing the function of the flow control valve. The flow control valve (20) comprises a housing (30) and a valve structure (40), wherein the housing has two ports (30a, 30b) and an internal space (S), wherein the internal space is shaped like a step portion (33, 38) and is connected to the two ports (30a, 30b), and the valve structure comprises: a throttling portion (62) which is arranged in a flow path connecting the two ports (30a, 30b); a contact portion (53) which has a surface (53a) which is not parallel to a moving direction and can block another flow path by contacting the step portion (33, 38); and a pressing member (70) which presses the contact portion (53) in such a way that the contact portion can contact the step portion (33, 38) of the housing (30), wherein the valve structure (40) is movably accommodated in the internal space (S) of the housing (30).

Description

Flow control valve and work machine
Technical Field
The present invention relates to a flow rate control valve that controls a flow rate of a flowing fluid, and a work machine provided with the flow rate control valve.
Background
Conventionally, in various fluid circuits, a flow rate control valve that controls a flow rate of a fluid flowing in the fluid circuit has been used. For example, in a work machine such as a construction vehicle driven by hydraulic pressure, a hydraulic circuit for supplying hydraulic oil to each hydraulic actuator of the work machine and a hydraulic circuit for supplying pilot pressure for operating a hydraulic device such as a reversing valve are each provided with a flow rate control valve for controlling the flow rate of oil flowing through the hydraulic circuit.
Japanese JPH08-312801a discloses a no-impact valve including an input port, an output port, a main body, a spool inserted into a fluid chamber in the main body so as to be movable in a longitudinal direction, a 1 st spring that biases the spool toward the input port, and a2 nd spring that biases the spool toward the output port. In this shock-free valve, when the pilot valve is set to the neutral position in order to stop the driving of the hydraulic actuator, the output of the pressure oil from the pilot valve is stopped, and the pressure on the input port side of the shock-free valve is rapidly lowered. Thus, the pressure oil flows from the output port into the output port side-sliding valve element chamber in the fluid chamber, and flows into the input port side-sliding valve element chamber through the throttle communication hole. At this time, a pressure difference is generated between the front and rear of the throttle communication hole, and the spool moves toward the input port. Thus, the opening formed by the 1 st communication hole that communicates the input port side-slipping valve element inner chamber and the 1 st annular groove is narrowed, and the flow of pressure oil passing therethrough is restricted. When the pressure oil further flows, the spool stops at a position where the pressure difference between the front and rear of the throttle communication hole and the biasing force of the 2 nd spring are balanced, the opening of the 1 st communication hole is adjusted, and the flow rate of the pressure oil from the output port side to the input port side is constant. Thus, even if the output of the pressure oil from the pilot valve is stopped rapidly, the speed of the return operation of the spool in the control valve can be reduced. Thus, the impact action of the pilot valve can be buffered.
In the reversing valve disclosed in japanese jp 55-107101a, two holes are provided that open to the outer wall of the housing, and a throttle valve with a check valve is respectively attached and fixed to these holes. The throttle valve with check valve controls the oil amount by the meter-in and meter-out modes, respectively. The two holes are formed in the same shape and the same size as each other, and two throttles with check valves can be replaced according to the use and the use condition. Thus, the throttle valve with a check valve disclosed in japanese JPS55-107101a has an advantage of being interchangeable, and thus, being able to satisfy a wide range of applications and conditions of use.
In the non-impact valve disclosed in jp h08-312801a, when pressure oil is output from the pilot valve to drive the hydraulic actuator, the pressure oil flowing into the non-impact valve through the input port flows into the input port side spool inner chamber through the communication path, the 1 st annular groove, the 1 st communication hole of the spool, and further flows to the output port side through the throttle communication hole. When the oil passes through the throttle communication hole, a pressure difference is generated between the front and rear of the throttle communication hole, and when the pressure difference is larger than the urging force of the 1 st spring, the spool moves toward the output port against the urging force of the 1 st spring. Thus, the 1 st annular groove and the 2 nd annular groove are communicated by the outer peripheral groove of the spool, and the pressure oil flows into the output port side-sliding spool inner chamber through the 2 nd communication hole. At this time, the no-impact valve 1 is interposed between the pilot valve and the control valve, and the operation of the control valve causes a delay in response. The delay of the response acts to alleviate the impact action of the control valve. On the other hand, if such a delay in response occurs at the start of driving of the hydraulic actuator, there is a problem in that the operator feels that the hydraulic actuator is slowly operated, and an uncomfortable feeling is generated.
Further, the check valve-equipped throttle valve disclosed in japanese unexamined patent publication No. 55-107101a is completely different from the check valve-equipped throttle valve for the meter-in system in terms of structural components, and when the check valve-equipped throttle valve is replaced, it is necessary to replace the entire check valve-equipped throttle valve with another check valve-equipped throttle valve. Therefore, the number of replacement parts increases, and thus there is a problem that the manufacturing cost of the throttle valve with the check valve, the replacement labor, and the time increase.
Disclosure of Invention
The present invention has been made in consideration of such a point, and an object of the present invention is to prevent a response delay from occurring in a flow control valve. The present invention also aims to reduce the number of replacement parts when changing the function of a flow control valve.
The flow control valve of the present invention comprises:
a housing having two ports, and an inner space in the shape of a stepped portion connected to the two ports, and
The valve structure includes a throttle portion provided in a flow path connecting the two ports, a contact portion having a surface non-parallel to a moving direction and capable of blocking the other flow path by being in contact with the stepped portion, and a pressing member for pressing the contact portion so that the contact portion can be in contact with the stepped portion of the housing, and is movably accommodated in the internal space of the housing.
In the flow control valve of the present invention, it may be,
The contact portion is formed at the valve member, the throttle portion is formed at the other valve member, and the pressing member presses the valve member and the other valve member away from each other.
In the flow control valve of the present invention, it may be,
The opening area of the opening of the flow path is changed by the other valve member being moved so as to approach the valve member.
In the flow control valve of the present invention, it may be,
The housing can receive the valve structure even if the valve structure is turned in the moving direction.
The flow control valve of the present invention comprises:
A housing having two ports and an internal space connecting the two ports internally, and
A valve structure having a contact portion that is capable of coming into contact with one port of the housing in the internal space of the housing, and a throttle portion that is disposed between the one port and the other port,
In a state where the contact portion of the valve structure is in contact with the housing, a flow path through a throttle portion is formed between the two ports,
A flow path is formed to bypass the throttle portion in a state where the contact portion of the valve structure is separated from the housing.
The flow control valve of the present invention comprises:
a housing having two ports, and an inner space in a shape having a1 st step portion and a2 nd step portion, connected to the two ports;
A 1 st valve member movably accommodated in the internal space of the housing, the 1 st valve member including a 1 st contact portion having a surface non-parallel to a moving direction and capable of contacting the 1 st step portion, a central passage connecting one side and the other side of the moving direction of the 1 st contact portion, the one side of the central passage being closed, the other side of the central passage being open, and an opening portion formed in a radial direction from the central passage at the one side of the 1 st contact portion;
A2 nd valve member movably accommodated in the internal space of the housing, including a2 nd contact portion contactable with the 2 nd step portion of the housing, a shaft portion integrally formed with the 2 nd contact portion and movable in the axial direction in the center passage of the 1 st valve member, a hollow portion open at one side in the movement direction of the shaft portion and closed at the other side, and a throttle portion formed in a radial direction from the hollow portion, and
A pressing member that moves the 1 st valve member and the 2 nd valve member away from each other.
The work machine of the present invention includes the flow control valve described above.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the present invention, it is possible to prevent response delay from occurring in the flow control valve. Further, according to the present invention, the number of replacement parts when changing the function of the flow control valve can be reduced.
Drawings
Fig. 1 is a diagram for explaining an embodiment of the present invention, and is a hydraulic circuit diagram showing an example of a hydraulic circuit of a work machine incorporating a flow rate control valve.
Fig. 2 is a hydraulic circuit diagram showing an example of the flow control valve.
Fig. 3 is a longitudinal sectional view showing an example of the flow control valve.
Fig. 4 is a perspective view showing the shape of the 2 nd contact portion of the 2 nd valve member of the flow control valve.
Fig. 5 is a diagram for explaining the operation of the flow control valve.
Fig. 6 is a diagram for explaining the operation of the flow control valve.
Fig. 7 is a longitudinal sectional view showing the flow control valve by turning the valve structure upside down.
Description of the reference numerals
10. Hydraulic circuit, 11, hydraulic pump, 12, hydraulic actuator, 13, spool, 16, pilot pump, 17, remote control valve, 19, tank, 20, flow control valve, 30, housing, 30a, 1 st port, 30b, 2 nd port, 31, 1 st housing, 33, 1 st stepped portion, 35, 2 nd housing, 40, valve structure, 50, 1 st valve member, 51, passage, 52, opening portion, 53, 1 st contact portion, 54, central passage, 60, 2 nd valve member, 61, shaft portion, 62, restriction portion, 63, hollow portion, 64, end portion, 65, 2 nd contact portion, 66, notch portion, 70, pressing member, a, central axis, E1, 1 st fluid pressure element, E2, 2 nd fluid pressure element, C1, 1 st pressure chamber, C2, 2 nd pressure chamber, S, internal space.
Detailed Description
An embodiment of the present invention will be described below with reference to the drawings. In the drawings attached to the present specification, for convenience of illustration and understanding, the scale, the aspect ratio, and the like are appropriately changed and enlarged with respect to the scale, the aspect ratio, and the like of the object.
The terms such as "parallel", "orthogonal", "identical", and the like, and values of length and angle used in the present specification, as well as the terms for determining the degree of the geometric conditions, are not limited to strict meanings, and are interpreted in a range including the degree of the function that can be expected to be the same.
Fig. 1 to 7 are views for explaining an embodiment of the present invention. In the present embodiment, an example in which the flow control valve 20 is used as a so-called surge-free valve in the hydraulic circuit 10 is described, and the use of the flow control valve 20 is not limited to this, and it can be used by being disposed in a portion of various fluid circuits where the flow rate of the fluid should be controlled. Fig. 1 is a hydraulic circuit diagram showing an example of a hydraulic circuit 10 of a work machine incorporating a flow control valve 20.
The hydraulic circuit 10 shown in fig. 1 includes a spool 13 that controls the flow rate of hydraulic oil discharged from the hydraulic pump 11 toward the hydraulic actuator 12, a remote control valve 17 that selects a flow path of pilot oil generated by the pilot pump 16, and a flow rate control valve (no-surge valve) 20 that controls the flow rate of pilot oil flowing between the spool 13 and the remote control valve 17.
The spool valve 13 has a spool 14. The position of the spool 14 in the axial direction (the longitudinal direction, the left-right direction in fig. 1) is changed by the action of the pilot pressure, which is the pressure of the pilot oil generated by the pilot pump 16, whereby the flow rate of the hydraulic oil discharged from the hydraulic pump 11 and directed to the hydraulic actuator 12 continuously changes. The pilot pump 16 is a hydraulic pump that discharges pilot oil having a constant pilot pressure at all times, and as an example, a gear pump is used. In the illustrated example, when the pilot pressure does not act on either one of the one end (right end in fig. 1) and the other end (left end in fig. 1) of the spool 14 in the axial direction, the spool 14 is positioned at the most one end side by receiving the pressing force of the spring 15. When the pilot pressure acts on one end of the spool 14 via the flow path 101 and the spool 14 moves toward the other end against the pressing force of the spring 15, the flow rate of the hydraulic oil discharged from the hydraulic pump 11 and toward the hydraulic actuator 12 increases. In addition, if the pilot pressure acts on the other end of the spool 14 via the flow path 102 and the spool 14 moves toward one end side, the flow rate of the hydraulic oil decreases.
The remote control valve 17 has an operation lever 18 operated by an operator, and the flow path of the pilot oil generated by the pilot pump 16 is selected from the flow path 101, the flow path 102, and the tank 19 and connected in accordance with the operation of the operation lever 18. When the lever 18 is in the neutral position, the remote control valve 17 communicates the pilot pump 16 with the tank 19. When the operation lever 18 is operated toward the 1 st operation position, the remote control valve 17 communicates the pilot pump 16 with the flow path 101, and communicates the flow path 102 with the tank 19. When the operation lever 18 is operated toward the 2 nd operation position different from the 1 st operation position, the remote control valve 17 communicates the pilot pump 16 with the flow path 102 and communicates the flow path 101 with the tank 19.
In the illustrated hydraulic circuit 10, when the operator does not operate the operation lever 18, the operation lever 18 of the remote control valve 17 is located at the neutral position, and the pilot oil generated by the pilot pump 16 is discharged to the tank 19 via the remote control valve 17. Thus, the pilot pressure does not act on either one of the one end and the other end of the spool 14.
When the operator operates the operation lever 18 toward the 1 st operation position, the pilot oil generated by the pilot pump 16 is directed to the spool 13 via the remote control valve 17 and the flow path 101, and the oil directed to the remote control valve 17 from the spool 13 via the flow path 102 is discharged to the tank 19. Thereby, the pilot pressure acts on one end of the spool 14, and the spool 14 moves toward the other end against the pressing force of the spring 15. Thus, the flow rate of the hydraulic oil discharged from the hydraulic pump 11 and directed to the hydraulic actuator 12 increases, and the hydraulic actuator 12 is driven in one direction. For example, a hydraulic cylinder for driving a boom of a hydraulic excavator is extended, and the boom is operated.
When the operator operates the operation lever 18 toward the 2 nd operation position, the pilot oil generated by the pilot pump 16 is directed to the spool 13 via the remote control valve 17 and the flow path 102, and the oil directed to the remote control valve 17 from the spool 13 via the flow path 101 is discharged to the tank 19. Thereby, the pilot pressure acts on the other end of the spool 14, and the spool 14 moves toward one end side. Thus, the flow rate of the hydraulic oil discharged from the hydraulic pump 11 and directed to the hydraulic actuator 12 decreases, and the hydraulic actuator 12 stops.
In such a hydraulic circuit 10, there are cases where movement of the spool 14 in one direction along the axial direction is required to be performed quickly, and movement in the other direction is required to be performed slowly. For example, a front link mechanism (boom, arm, and bucket) mounted on a work machine such as a hydraulic excavator and driven by a hydraulic circuit has a relatively large weight. In this case, if the front link mechanism is suddenly stopped after the operation is performed by the hydraulic pressure, an impact due to a large inertial force of the front link mechanism is generated, and thus the entire work machine may swing greatly. Since the operator cannot perform the following operation until the swing is subsided, the efficiency of the work using the work machine is lowered. Therefore, in the hydraulic circuit 10 shown in fig. 1, a flow control valve (no-shock valve) 20 is provided in the middle of a flow path 101 that communicates the remote control valve 17 and the spool 13.
Fig. 2 is a hydraulic circuit diagram for explaining an example of the flow control valve 20. In the illustrated example, the flow control valve 20 is disposed between the 1 st fluid pressure element E1 and the 2 nd fluid pressure element E2, and causes the fluid from the 1 st fluid pressure element E1 to the 2 nd fluid pressure element E2 to flow rapidly, and causes the fluid from the 2 nd fluid pressure element E2 to the 1 st fluid pressure element E1 to flow slowly. When the flow control valve 20 is incorporated in the hydraulic circuit 10 shown in fig. 1, for example, the 1 st fluid pressure element E1 is the remote control valve 17, and the 2 nd fluid pressure element E2 is the spool 13. However, the present invention is not limited to this, and the 1 st and 2 nd fluid pressure elements E1 and E2 connected to the flow control valve 20 may be other fluid pressure elements such as other hydraulic elements and pneumatic elements.
The flow control valve 20 shown in fig. 2 includes a throttle 22, a control valve 24, and a check valve 28. In fig. 2, the throttle 22, the control valve 24, the check valve 28, and the flow paths 103 and 104 are each conceptually represented by their functions.
The throttle 22 is provided in the middle of the flow path 103 that communicates the 1 st fluid pressure element E1 and the 2 nd fluid pressure element E2, and restricts the flow rate per unit time of the oil (fluid) flowing through the flow path 103.
The control valve 24 controls the flow rate per unit time of the oil flowing through the flow path 103. The control valve 24 changes the cross-sectional area of the flow path 103 according to the difference between the pressure of the oil at the position P1 of the throttle portion 22 on the 1 st fluid pressure element E1 side and the pressure of the oil at the position P2 of the throttle portion 22 on the 2 nd fluid pressure element E2 side in the flow path 103, thereby changing the flow rate per unit time of the oil flowing through the flow path 103. In the illustrated example, when the pressure of the oil at the position P1 is equal to the pressure of the oil at the position P2, the cross-sectional area of the flow path 103 in the control valve 24 becomes maximum. In the present embodiment, the opening area of the opening 52 of the passage 51 of the 1 st valve member 50 described later becomes maximum. If the pressure of the oil at the position P2 is greater than the pressure of the oil at the position P1, the control valve 24 reduces the cross-sectional area of the flow path 103, and thereby reduces the flow rate per unit time of the oil flowing through the flow path 103. In the present embodiment, the opening 52 is partially closed by an end 64 of the 2 nd valve member 60 by moving the 2 nd valve member 60 to be described later so as to approach the 1 st valve member 50. Thus, the control valve 24 functions as an additional throttle portion that restricts the flow rate per unit time of the oil flowing through the flow path 103. In particular, the control valve 24 functions as a variable throttle valve capable of continuously changing the cross-sectional area of the flow path 103.
The check valve 28 is provided in the middle of the flow path 104, and the flow path 104 branches from a position P3 of the control valve 24 on the 1 st fluid pressure element E1 side in the flow path 103, bypasses the throttle 22 and the control valve 24, and merges with the flow path 103 at a position P4 of the throttle 22 on the 2 nd fluid pressure element E2 side. That is, the check valve 28 is provided in parallel with the throttle portion 22 and the control valve 24. In the present embodiment, the 1 st valve member 50 having the 1 st contact portion 53 described later functions as the check valve 28. The oil flowing from the position P3 to the check valve 28 via the flow path 104 is directed to the position P4 via the check valve 28. On the other hand, the flow of the oil flowing into the check valve 28 from the position P4 through the flow path 104 is blocked by the check valve 28, and cannot go to the position P3.
In the flow control valve 20 shown in fig. 2, the oil from the 1 st fluid pressure element E1 toward the 2 nd fluid pressure element E2 flows along the flow path 103 toward the position P3. The check valve 28 permits the flow of oil from position P3 toward position P4 via the flow path 104. The throttle 22 and the control valve 24 also allow the flow of oil from the position P3 to the position P4 via the flow path 103, and the flow rate per unit time thereof is restricted by the throttle 22. Thus, the oil from the position P3 toward the position P4 mainly flows through the flow path 104, that is, through the check valve 28. Thereafter, the oil flows from the position P4 along the flow path 103 toward the 2 nd fluid pressure element E2.
The oil from the 2 nd fluid pressure element E2 toward the 1 st fluid pressure element E1 is directed along the flow path 103 toward the position P4. Here, the check valve 28 does not allow the oil to flow from the position P4 toward the position P3 via the flow path 104. In this case, the oil from the position P4 toward the position P3 flows in the throttle 22. Here, the flow rate per unit time of the oil flowing through the throttle 22 is limited. Thus, a difference occurs between the pressure of the oil at the positions P2, P4 of the throttle 22 on the 2 nd fluid pressure element E2 side and the pressure of the oil at the positions P1, P3 of the throttle 22 on the 1 st fluid pressure element E1 side (control valve 24 side). Specifically, the pressure of the oil at positions P2, P4 is greater than the pressure of the oil at positions P1, P3. The pressure of the oil at positions P2, P4 is led to the control valve 24. Thus, the control valve 24 reduces the cross-sectional area of the flow path 103, and reduces the flow rate per unit time of the oil flowing through the flow path 103. At this time, the control valve 24 functions as an additional throttle portion, and the flow rate per unit time of the oil flowing through the control valve 24 is limited. That is, the flow rate per unit time of the oil, the flow rate per unit time of which is restricted by the restriction portion 22, is further restricted in the control valve 24.
When the oil passes from the 1 st fluid pressure element E1 to the 2 nd fluid pressure element E2, the check valve 28 allows the flow of the oil, and therefore, the oil rapidly passes through the flow control valve 20. When the 1 st fluid pressure element E1 is the remote control valve 17 and the 2 nd fluid pressure element E2 is the spool 13, the pilot oil from the remote control valve 17 to the spool 13 passes through the flow control valve 20 to rapidly actuate the spool 13. Thus, the flow rate of the hydraulic oil that is discharged from the hydraulic pump 11 and toward the hydraulic actuator 12 increases rapidly.
The check valve 28 does not allow the flow of oil when the oil passes from the 2 nd fluid pressure element E2 to the 1 st fluid pressure element E1. Thus, the flow rate per unit time of the oil is restricted by the throttle portion 22, and the flow rate per unit time is further restricted in the control valve 24. When the 1 st fluid pressure element E1 is the remote control valve 17 and the 2 nd fluid pressure element E2 is the spool 13, the flow rate per unit time of the oil from the spool 13 to the remote control valve 17 is greatly restricted by the flow rate control valve 20. Thereby, the spool 13 operates at a slow speed. Thus, the flow rate of the hydraulic oil that is discharged from the hydraulic pump 11 and toward the hydraulic actuator 12 decreases at a slow rate.
In the example shown in fig. 1 and 2, when the hydraulic oil starts to be sent to the hydraulic actuator 12, the flow rate of the hydraulic oil toward the hydraulic actuator 12 can be rapidly increased. This can suppress occurrence of an operation delay in the hydraulic actuator 12 when the hydraulic actuator 12 starts to be driven. Therefore, when the hydraulic actuator 12 starts to be driven, the operator who operates the operation lever 18 can be prevented from feeling uncomfortable or from further operating the hydraulic actuator 12 to perform unnecessary operation of the operation lever 18.
On the other hand, when the supply of the hydraulic oil to the hydraulic actuator 12 is stopped, the flow rate of the hydraulic oil to the hydraulic actuator 12 can be reduced at a slow rate. This effectively suppresses sudden stop of the hydraulic actuator 12 and occurrence of an impact caused by a large inertial force of the front link mechanism in the work machine. Thus, the entire work machine is prevented from swinging largely, and the operator can quickly perform the following operation. That is, the work efficiency of the work machine can be effectively improved.
Next, an example of a specific structure of the flow control valve 20 according to the present embodiment will be described in detail with reference to fig. 3 and 4. Fig. 3 is a longitudinal sectional view showing an example of the flow control valve 20, and fig. 4 is a perspective view showing the shape of the 2 nd contact portion 65 of the 2 nd valve member 60 of the flow control valve 20.
In the example shown in fig. 3, the flow control valve 20 includes a housing 30 having two ports 30a and 30b, and an internal space S having a shape of stepped portions 33 and 38, and a valve structure 40 connected to the two ports 30a and 30b, and the valve structure 40 is held in the housing 30. In particular, the housing 30 has two ports 30a, 30b, and an internal space S in the shape of having a 1 st step portion 33 and a 2 nd step portion 38, connected to the two ports 30a, 30 b. The valve structure 40 includes a throttle 62 provided in a 1 st flow path described later that connects the two ports 30a and 30b, a 1 st contact 53 having a surface 53a that is not parallel to the moving direction and capable of blocking a 2 nd flow path described later by coming into contact with the stepped portions 33 and 38 of the housing 30, and a pressing member 70 that presses the 1 st contact 53 so that the 1 st contact 53 can come into contact with the stepped portions 33 and 38 of the housing 30, and the valve structure 40 is movably accommodated in the internal space S of the housing 30. The valve structure 40 includes a 1 st valve member (one valve member) 50 and a 2 nd valve member (the other valve member) 60, which are movably accommodated in the housing 30, and a pressing member 70, which is disposed between the 1 st valve member 50 and the 2 nd valve member 60. In the illustrated example, the 1 st contact portion 53 is formed in the 1 st valve member 50, the throttle portion 62 is formed in the 2 nd valve member 60, and the pressing member 70 presses the 1 st valve member 50 and the 2 nd valve member 60 so as to separate the 1 st valve member 50 and the 2 nd valve member 60 from each other. The following describes each constituent element of the flow control valve 20. In fig. 3, the direction along the central axis a of the flow control valve 20 is referred to as an axis direction da, the side of the outer member 90 (lower side in fig. 3) with respect to the flow control valve 20 along the axis direction da is referred to as "one side", and the side opposite to the "one side" (upper side in fig. 3) is referred to as "the other side". In the example shown in fig. 3, the flow control valve 20 communicates with the 1 st fluid pressure element E1 on one side portion and communicates with the 2 nd fluid pressure element E2 on the other side portion.
The case 30 functions as a case that partitions the internal space S. The housing 30 has two ports, namely, a1 st port 30a and a2 nd port 30 b. In the illustrated example, the housing 30 includes a1 st housing 31 having a1 st port 30a and a2 nd housing 35 having a2 nd port 30b, and is coupled to the 1 st housing 31, and the internal space S is defined by the 1 st housing 31 and the 2 nd housing 35. The housing 30 has stepped portions 33, 38 for the 1 st contact portion 53 to contact and separate with the movement of the valve structure 40. Thus, the housing 30 has two ports 30a, 30b, and an internal space S in the shape of a stepped portion 33, 38 connected to the two ports 30a, 30 b. The case 30 can be easily manufactured by dividing the case 30 into the 1 st case 31 and the 2 nd case 35 to form the case 30. The 1 st screw portion 41 is formed in the housing 30, and the flow rate control valve 20 (housing 30) is attached to the outer member 90 by screwing the 1 st screw portion 41 to the outer screw portion 94 formed in the recess 92 of the outer member 90. The housing 30 has a substantially cylindrical (cylindrical) shape as a whole, and has a substantially circular shape when viewed along the axis direction da. The outer member 90 is part of any hydraulic device. The external member 90 is a member that communicates with the 1 st fluid pressure element E1 (remote control valve 17). In the illustrated example, the 1 st port 30a communicates with the 1 st fluid pressure element E1, and the 2 nd port 30b communicates with the 2 nd fluid pressure element E2.
The 1 st housing 31 has a small diameter portion 31a and a large diameter portion 31b located on the other side with respect to the small diameter portion 31 a. The small diameter portion 31a has a relatively small diameter with respect to the diameter of the large diameter portion 31b. A1 st screw portion 41 is formed on one side of the outer periphery of the small diameter portion 31 a. The 1 st screw portion 41 is constituted by an external screw. The large diameter portion 31b has a relatively large diameter with respect to the diameter of the small diameter portion 31 a. The small diameter portion 31a and the large diameter portion 31b each have a substantially cylindrical shape.
A through hole 32 penetrating from one side to the other side is formed in the 1 st housing 31. In the illustrated example, the through hole 32 is formed by a combination of 3 holes (32 a to 32 c) having diameters different from each other so as to gradually increase from one side to the other side. The hole having the smallest cross-sectional dimension (diameter) and opening at the end face of the 1 st housing 31 is referred to as a small-diameter hole 32a, the hole having the largest diameter and opening at the end face of the 1 st housing 31 is referred to as a large-diameter hole 32c, and the hole having the diameter between the diameter of the small-diameter hole 32a and the diameter of the large-diameter hole 32c and located between the small-diameter hole 32a and the large-diameter hole 32c along the axial direction da is referred to as a medium-diameter hole 32b. In the illustrated example, the small diameter bore 32a constitutes the 1 st port 30a. The holes 32a to 32c are coaxially arranged. A 2 nd screw portion 42 is formed on the inner peripheral surface of the through hole 32. In particular, the 2 nd screw portion 42 is formed on the inner peripheral surface of the large diameter hole 32c. The 2 nd screw portion 42 is constituted by an internal screw. The other end of the small-diameter hole 32a forms a 1 st step 33 that contacts a 1 st contact 53 of the 1 st valve member 50, which will be described later. In addition, the intermediate diameter hole 32b may be omitted. That is, the through hole 32 may have a small diameter hole 32a and a large diameter hole 32c.
The 2 nd casing 35 is formed in a substantially cylindrical shape as a whole, and is attached to the 1 st casing 31 at one side portion thereof. A3 rd screw portion 43 is formed at one side portion of the outer periphery of the 2 nd housing 35, and a4 th screw portion 44 is formed at the other side portion of the outer periphery of the 2 nd housing 35. The 3 rd screw portion 43 and the 4 th screw portion 44 are each constituted by external screw threads. In the illustrated example, one end of the 2 nd housing 35 is positioned in the through hole 32 (large diameter hole 32 c) of the 1 st housing 31, and the 3 rd screw portion 43 of the 2 nd housing 35 is screwed to the 2 nd screw portion 42 of the 1 st housing 31, whereby the 2 nd housing 35 is attached to the 1 st housing 31.
A through hole 36 is formed in the 2 nd casing 35 so as to pass through from one side to the other side. The through hole 36 is formed by a combination of two holes (36 a, 36 b) having different diameters from each other. The hole having a relatively smaller diameter on the other side is referred to as a small-diameter hole 36a, and the hole having a relatively larger diameter on one side of the small-diameter hole 36a is referred to as a large-diameter hole 36b. In the illustrated example, the small diameter bore 36a constitutes the 2 nd port 30b. The end of the small-diameter hole 36a is an opening 37 that opens into the large-diameter hole 36b. The large diameter hole 36b opens at one end face of the 2 nd case 35. A 2 nd step portion 38 is formed at the position of the large diameter hole 36b on the other side, and the 2 nd step portion 38 has a bearing surface for receiving a 2 nd contact portion 65 of the 2 nd valve member 60, which will be described later. The support surface is formed by a surface facing one side and orthogonal to the central axis a.
In the example shown in fig. 3, the valve structure 40 is disposed in the through-hole 32 of the 1 st housing 31 and the through-hole 36 of the 2 nd housing 35. That is, the 1 st valve member 50, the 2 nd valve member 60, and the pressing member 70 are disposed in the through holes 32, 36. Thus, the valve structure 40 is disposed between the 1 st port 30a and the 2 nd port 30b of the housing 30. The internal space S is defined by the intermediate diameter hole 32b, the large diameter hole 32c of the 1 st housing 31, and the large diameter hole 36b of the 2 nd housing 35.
A seal member 75 is disposed between the 1 st housing 31 and the 2 nd housing 35. A seal member 77 is disposed between the case 30 and the exterior member 90, in particular, between the 1 st case 31 and the exterior member 90. The seal members 75, 77 are formed of, for example, O-rings, and prevent oil from leaking between the 1 st housing 31 and the 2 nd housing 35 or between the housing 30 and the outer member 90.
The 1 st valve member (valve member) 50 functions as the control valve 24 described with reference to fig. 2 in cooperation with the 2 nd valve member 60, and functions as the check valve 28 described with reference to fig. 2 in cooperation with the 1 st stepped portion 33 of the 1 st housing 31. In the example shown in fig. 3, the 1 st valve member 50 is composed of a combination of 3 portions (50 a to 50 c) having mutually different cross-sectional dimensions (diameters) so as to become gradually larger from one side to the other side. That is, the 1 st valve member 50 has a small diameter portion 50a located at the most one side in the axial direction da and having the smallest diameter, a large diameter portion 50c located at the most other side and having the largest diameter, and a middle diameter portion 50b located between the small diameter portion 50a and the large diameter portion 50c and having a diameter between the diameter of the small diameter portion 50a and the diameter of the large diameter portion 50 c. The small diameter portion 50a, the medium diameter portion 50b, and the large diameter portion 50c each have a circular-shaped contour when viewed from the axial direction da. The large diameter portion 50c of the 1 st valve member 50 is movable in the axial direction da while being in contact with the inner peripheral surface of the large diameter hole 36b of the 2 nd housing 35 via an oil film.
The small diameter portion 50a has a substantially cylindrical shape with one side thereof closed. A plurality of passages 51 formed as through holes are provided in the side surface of the small diameter portion 50a extending in the axial direction da. The passage 51 has an opening 52 that opens into a central passage 54 described later. The opening 52 is formed in a radial direction from the central passage 54 on the 1 st contact 53 side described later. In the illustrated example, the passage 51 communicates with the 1 st fluid pressure element E1 via the 1 st port 30a (small-diameter hole 32 a) of the 1 st housing 31, the recess 92 of the outer member 90, and the flow path 96.
A1 st contact portion (contact portion) 53 is provided at a portion of the outer peripheral surface of the 1 st valve member 50 between the small diameter portion 50a and the intermediate diameter portion 50b, and the 1 st contact portion (contact portion) 53 has a seating surface that is not parallel to the axial direction da, which is the moving direction of the 1 st valve member 50. The seat surface extends in a direction inclined with respect to both the moving direction of the 1 st valve member 50 and the direction orthogonal to the moving direction. More specifically, the seating surface is formed by a part of a conical surface obtained by rotating a straight line passing through a point on the central axis a on the side of the intermediate diameter portion 50b and inclined with respect to the central axis a around the central axis a. The small diameter portion 50a and the intermediate diameter portion 50b of the 1 st valve member 50 are connected via the 1 st contact portion 53. The 1 st contact portion (contact portion) 53 is configured to be capable of contacting the 1 st port 30a of the housing 30 in the internal space S of the housing 30. As will be described later, even if the valve structure 40 is turned in the movement direction of the 1 st valve member 50, the housing 30 of the flow control valve 20 can accommodate the valve structure 40. In this case, the 1 st contact portion (contact portion) 53 is configured to be able to contact the 2 nd port 30b of the housing 30 in the internal space S of the housing 30. Thus, the valve structure 40 has a1 st contact portion 53 that can contact with the ports 30a, 30b of the housing 30 in the internal space S of the housing 30, and a throttle portion 62 that is disposed between the ports 30a, 30b and the other ports 30b, 30 a.
When the 1 st valve member 50 moves to one side in the axial direction da and the 1 st contact portion 53 contacts the 1 st step portion 33 of the 1 st housing 31 over the entire circumference around the central axis a, the oil is prevented from flowing between the outer circumference of the 1 st valve member 50 and the inner circumference of the through hole 32 of the 1 st housing 31, in particular, between the 1 st contact portion 53 and the 1 st step portion 33. On the other hand, when the 1 st valve member 50 moves to the other side in the axial direction da and the 1 st contact portion 53 is separated from the 1 st step portion 33, oil is allowed to flow between the outer periphery of the 1 st valve member 50 and the inner periphery of the through hole 32 of the 1 st housing 31.
The 1 st valve member 50 has a central passage 54 holding a shaft portion 61 of the 2 nd valve member 60, which will be described later. A large-diameter hole 55 opened on the other side and a central passage 54 opened in the large-diameter hole 55 are provided in the 1 st valve member 50. The central passage 54 and the large-diameter hole 55 each have a circular-shaped profile as viewed from the axial direction da. The large-diameter hole 55 has a diameter larger than that of the central passage 54. In the illustrated example, the central passage 54 extends along the central axis a across the small diameter portion 50a and the intermediate diameter portion 50b, and the large diameter hole 55 extends along the central axis a inside the large diameter portion 50 c. In the illustrated example, the central passage 54 connects one side and the other side in the movement direction of the 1 st contact portion 53, one side of the central passage 54 is closed, and the other side of the central passage 54 is opened.
A hole 56 is formed in the large diameter portion 50c of the 1 st valve member 50, which passes from the outer peripheral surface to the inner peripheral surface (large diameter hole 55) of the large diameter portion 50 c. The cross-sectional area of the holes 56 has an area that does not substantially restrict the flow rate of oil per unit time. For example, the cross-sectional area of the hole 56 is preferably larger than the cross-sectional area of a throttle 62 of the 2 nd valve member 60 described later. A1 st support portion 57 is formed at a step portion connecting the central passage 54 and the large-diameter hole 55, and the 1 st support portion 57 is configured to support the pressing member 70 and receive a pressing force of the pressing member 70. The 1 st support portion 57 is formed of a surface orthogonal to the central axis a.
The 2 nd valve member (another valve member) 60 has a shaft portion 61 and a 2 nd contact portion 65 located on the other side of the shaft portion 61. The shaft portion 61 is formed in a substantially cylindrical shape as a whole, and extends along the axial direction da. In the illustrated example, a central axis extending in the longitudinal direction of the shaft portion 61 coincides with the central axis a. That is, the central axis a can also be said to be the central axis of the shaft portion 61. The shaft portion 61 is integrally formed with the 2 nd contact portion 65, and the shaft portion 61 is movable in the axial direction da in the center passage 54 of the 1 st valve member 50. A hollow 63 is formed inside the shaft 61. The hollow 63 is formed as a hole that is open on one side and closed on the other side. That is, one side of the hollow portion 63 located in the moving direction of the shaft portion 61 is opened, and the other side is closed. The hollow portion 63 includes a central axis a and extends along an axis direction da. The cross section of the hollow portion 63 orthogonal to the central axis a has a circular shape, and has the same size as each other at each position along the axis direction da. The 2 nd valve member 60 is movably held in the central passage 54 of the 1 st valve member 50. In particular, an end portion 64 of the 2 nd valve member 60 (a tip end portion of the shaft portion 61) is held in the central passage 54. In other words, a portion of the shaft portion 61 including the one-side end portion 64 is inserted into the central passage 54. Thereby, the 2 nd valve member 60 is movable with respect to the 1 st valve member 50 along the axial direction da toward the opening 52 of the passage 51 toward the 1 st valve member 50 (toward one side) and away from the opening 52 (toward the other side). And, the opening 52 is partially closed by the end 64 with the movement of the 2 nd valve member 60. In addition, since the opening 52 is partially closed, the opening area of the opening 52 varies. Thus, the opening area of the opening 52 of the oil flow path changes by the 2 nd valve member 60 moving so as to approach the 1 st valve member 50.
A throttle 62 communicating with the hollow 63 is formed in the shaft 61 of the 2 nd valve member 60. The throttle 62 is formed at a position exposed from the central passage 54 when the 2 nd valve member 60 is located at the most lateral position. That is, even in the case where the 2 nd valve member 60 is located at any one of the positions within the movement range thereof, the throttle 62 is always exposed from the central passage 54. In the illustrated example, the throttle 62 extends in a direction orthogonal to the central axis a. That is, the throttle 62 is formed in the radial direction from the hollow 63. The cross section of the throttle portion 62 orthogonal to the direction in which the throttle portion 62 extends has a circular shape, and has the same size as each other at each position along the direction in which the throttle portion 62 extends. The throttle 62 may extend in a direction inclined with respect to both the direction in which the central axis a extends (the axis direction da) and the direction orthogonal to the central axis a. The cross section of the throttle 62 may have different dimensions at each position along the direction in which the throttle 62 extends. For example, the cross section of the throttle 62 may have a smaller size in a part of the range along the direction in which the throttle 62 extends than in other ranges. The minimum cross-sectional area of the throttle 62 is set to a level that can restrict the flow rate per unit time of the oil flowing in the throttle 62.
The internal space S of the housing 30 is divided by the 2 nd valve member 60 into a 1 st pressure chamber C1 including the hollow portion 63 and a2 nd pressure chamber C2 communicating with the hollow portion 63 via the throttle portion 62. In the illustrated example, the 1 st pressure chamber C1 is a space within the hollow portion 63 and the central passage 54, and the 2 nd pressure chamber C2 is a space outside the 2 nd valve member 60 in the internal space S. As described above, the opening 52 of the passage 51 opens into the central passage 54. Thus, the opening 52 may be said to open in the 1 st pressure chamber C1. In the illustrated example, the 1 st pressure chamber C1 communicates with the 1 st port 30a (small-diameter hole 32 a) of the 1 st housing 31, the recess 92 of the outer member 90, and the flow path 96 via the opening 52.
The 2 nd contact portion 65 has an outer dimension larger than the outer dimension of the shaft portion 61 and the inner dimension of the central passage 54 as viewed along the axis direction da. Thus, the 2 nd contact portion 65 cannot enter the central passage 54. The 2 nd contact portion 65 has an outer dimension larger than the inner dimension of the small-diameter hole 36a of the through hole 36 and smaller than the inner dimension of the large-diameter hole 36b when viewed along the axial direction da. Thus, the 2 nd contact portion 65 can enter the large diameter hole 36b, but cannot enter the small diameter hole 36 a. That is, when the 2 nd valve member 60 moves to the other side, the 2 nd contact portion 65 contacts the 2 nd step portion 38 connecting the small diameter hole 36a and the large diameter hole 36b, and the 2 nd valve member 60 cannot move further to the other side.
The surface of the 2 nd contact portion 65 facing one side includes a 2 nd support portion 67, and the 2 nd support portion 67 supports the pressing member 70 and receives the pressing force of the pressing member 70. In the illustrated example, the pressing member 70 is a coil spring, and is disposed between the 2 nd support portion 67 and the 1 st support portion 57 in a compressed state. Thus, the pressing member 70 generates a pressing force in a direction in which the pressing member 70 extends, in other words, in a direction in which the 1 st valve member 50 and the 2 nd valve member 60 are away from each other, due to the elastic force thereof. The coil spring constituting the pressing member 70 is disposed so as to surround the shaft portion 61. The pressing member 70 is not limited to a coil spring, and various members capable of generating a pressing force can be used.
As shown in fig. 4, the 2 nd contact portion 65 has a notch portion 66 at the outer peripheral portion. In the illustrated example, the 2 nd contact portion 65 has two notch portions 66 so as to be symmetrical with respect to the central axis a. The notch 66 extends inward from the outer peripheral portion of the 2 nd contact portion 65 beyond the outline of the opening 37 of the small-diameter hole 36a of the 2 nd housing 35 as viewed in the axial direction da. Thereby, a gap 81 is formed between the notch 66 and the opening 37. The gap 81 has an opening area that does not substantially limit the flow rate per unit time of the oil flowing through the gap 81. In the illustrated example, each notch 66 is formed by linearly removing a part of the outer peripheral portion of the 2 nd contact portion 65 as viewed from the axis direction da, but the specific shape of the notch 66 is not limited thereto. For example, the notch 66 may be formed in a groove shape facing inward from the outer peripheral portion of the 2 nd contact portion 65. The 2 nd contact portion 65 may have 1 notch portion 66 or 3 or more notch portions 66. Instead of the notch 66, a through hole penetrating from one side to the other side may be provided in the 2 nd contact portion 65, and the through hole may be a gap 81.
Next, the operation of the flow control valve 20 will be described with reference to fig. 3, 5, and 6.
When the remote control valve 17 is not operated and the pilot pressure from the pilot pump 16 does not act on the flow control valve 20, the pressure of the oil in the 1 st pressure chamber C1 is equal to the pressure of the oil in the 2 nd pressure chamber C2. As shown in fig. 3, the 1 st valve member 50 is located on the opposite side (side) from the 2 nd valve member 60 due to the pressing force of the pressing member 70. At this time, the 1 st contact portion 53 of the 1 st valve member 50 is pressed against the 1 st step portion 33 of the 1 st housing 31. In addition, the 2 nd valve member 60 is located on the opposite side (the other side) from the 1 st valve member 50 due to the pressing force of the pressing member 70. At this time, the 2 nd contact portion 65 of the 2 nd valve member 60 is pressed against the support surface of the 2 nd step portion 38 of the 2 nd housing 35. In the illustrated example, at this time, the opening 52 of the passage 51 is not closed by the end 64 of the 2 nd valve member 60, and the opening 52 has an opening area that does not substantially limit the flow rate per unit time of the oil flowing through the opening 52.
In a state where the 1 st contact portion 53 of the 1 st valve member 50 is in contact with the housing 30 (1 st step portion 33), a1 st flow path (flow path) including the throttle portion 62 is formed between the 1 st port 30a and the 2 nd port 30 b. Specifically, a1 st flow path including the passage 51, the central passage 54, the hollow 63, the throttle 62, and the gap 81 is formed between the 1 st port 30a and the 2 nd port 30 b. Thus, in a state where the 1 st contact portion 53 of the 1 st valve member 50 is in contact with the housing 30, the flow path (2 nd flow path, another flow path) bypassing the throttle portion 62 is blocked, and the oil flowing between the 1 st port 30a and the 2 nd port 30b inevitably passes through the throttle portion 62.
When the operation lever 18 of the remote control valve 17 is operated by the operator and the pilot pressure from the pilot pump 16 acts on the flow control valve 20 via the 1 st fluid pressure element E1 (remote control valve 17), the pilot pressure is introduced into the 1 st pressure chamber C1 via the flow path 96, the concave portion 92, the 1 st port 30a (small diameter hole 32 a), and the passage 51. At this time, the throttle 62 restricts the flow rate per unit time of the oil flowing through the throttle 62. Thus, the pressure of the oil in the 1 st pressure chamber C1 is greater than the pressure of the oil in the 2 nd pressure chamber C2. Specifically, due to the flow rate limiting effect of the throttle 62, the rate of rise of the pressure of the oil in the 2 nd pressure chamber C2 is slower than the rate of rise of the pressure of the oil in the 1 st pressure chamber C1 and the 1 st port 30a, and a difference (differential pressure) occurs between the pressure of the oil in the 1 st pressure chamber C1 and the 1 st port 30a and the pressure of the oil in the 2 nd pressure chamber C2.
If the pressure difference exceeds a certain level, the force of pushing the 1 st valve member 50 toward the 2 nd valve member 60 (the other side) due to the pressure difference is larger than the force of pushing the 1 st valve member 50 toward the opposite side (the one side) of the pressing member 70 from the 2 nd valve member 60, and the 1 st valve member 50 moves toward the 2 nd valve member 60 side. Thereby, the 1 st contact portion 53 of the 1 st valve member 50 is separated from the 1 st step portion 33 of the 1 st housing 31. At this time, the 1 st port 30a and the 2 nd pressure chamber C2 communicate via the gap 83 between the 1 st contact portion 53 and the 1 st step portion 33. Accordingly, as shown in fig. 5, the oil flowing from the 1 st fluid pressure element E1 to the 1 st port 30a flows toward the 2 nd fluid pressure element E2 through the gap 83, the hole 56, the large-diameter hole 55, the gap 81, and the 2 nd port 30b (the small-diameter hole 36 a) in this order. Thereby, the 2 nd fluid pressure element E2 operates.
When the 1 st contact portion 53 of the 1 st valve member 50 is separated from the 1 st step portion 33 of the 1 st housing 31, the oil rapidly flows into the 2 nd pressure chamber C2 from the 1 st port 30a via the gap 83, and a difference (differential pressure) between the pressure of the oil in the 1 st pressure chamber C1 and the 1 st port 30a and the pressure of the oil in the 2 nd pressure chamber C2 becomes small. Since the pressure difference becomes small, the force pushing the 1 st valve member 50 toward the 2 nd valve member 60 becomes small, and the 1 st valve member 50 is pushed back toward the opposite side to the 2 nd valve member 60 due to the pressing force of the pressing member 70. At this time, since the gap 83 becomes smaller, a pressure difference is newly generated between the 1 st pressure chamber C1 and the 1 st port 30a and the 2 nd pressure chamber C2, whereby the 1 st valve member 50 is pushed toward the 2 nd valve member 60 side against the pressing force of the pressing member 70. Thus, the 1 st valve member 50 stops at a position where the pressing force of the pressing member 70 that pushes the 1 st valve member 50 to the opposite side to the 2 nd valve member 60 is balanced with the pressing force that pushes the 1 st valve member 50 to the other side due to the pressure difference generated between the 1 st pressure chamber C1 and the 1 st port 30a and the 2 nd pressure chamber C2. Further, the 1 st valve member 50 may not completely stop due to a slight variation in pressure difference generated between the 1 st pressure chamber C1 and the 1 st port 30a and the 2 nd pressure chamber C2, and its position may slightly vary.
In a state where the 1 st contact portion 53 of the 1 st valve member 50 is separated from the housing 30 (1 st step portion 33), a2 nd flow path (another flow path) bypassing the throttle portion 62 is formed between the 1 st port 30a and the 2 nd port 30 b. Specifically, a2 nd flow path including the gap 83, the hole 56, the large diameter hole 55, and the gap 81 is formed between the 1 st port 30a and the 2 nd port 30 b. Thus, in a state where the 1 st contact portion 53 of the 1 st valve member 50 is separated from the housing 30, most of the oil flowing between the 1 st port 30a and the 2 nd port 30b flows without passing through the throttle portion 62. In this case, a part of the oil flowing between the 1 st port 30a and the 2 nd port 30b can pass through the throttle 62.
When the operation lever 18 of the remote control valve 17 is operated by an operator and the 1 st pressure chamber C1 and the 1 st port 30a communicate with the tank 19 via the recess 92, the flow path 96, and the 1 st fluid pressure element E1 (remote control valve 17), the differential pressure between the 1 st pressure chamber C1 and the 1 st port 30a and the 2 nd pressure chamber C2 is drastically reduced. That is, the pressing force that pushes the 1 st valve member 50 toward the 2 nd valve member 60 is drastically reduced. Thereby, the 1 st valve member 50 moves to the opposite side of the 2 nd valve member 60 due to the pressing force of the pressing member 70, the 1 st contact portion 53 of the 1 st valve member 50 is pressed against the 1 st step portion 33 of the 1 st housing 31, and the gap 83 is closed. Thus, the 1 st pressure chamber C1 and the 2 nd pressure chamber C2 communicate with each other only by the throttle 62. Thus, the pressure of the oil in the 2 nd pressure chamber C2 is greater than the pressure of the oil in the 1 st pressure chamber C1. Specifically, due to the flow rate limiting effect of the throttle 62, the pressure of the oil in the 2 nd pressure chamber C2 decreases at a slower rate than the pressure of the oil in the 1 st pressure chamber C1, and a difference (differential pressure) occurs between the pressure of the oil in the 1 st pressure chamber C1 and the pressure of the oil in the 2 nd pressure chamber C2. As shown in fig. 6, the 2 nd valve member 60 moves toward the 1 st valve member 50 (one side) against the pressing force of the pressing member 70 due to the pressing force caused by the pressure difference.
By the 2 nd valve member 60 moving in a manner approaching the 1 st valve member 50, the flow path including the throttle 62 is partially closed. Specifically, as the 2 nd valve member 60 moves, the opening 52 of the passage 51 is partially closed by the end 64 of the 2 nd valve member 60. At this time, as the pressure difference between the 1 st pressure chamber C1 and the 2 nd pressure chamber C2 increases, the difference between the pressing force toward the 1 st valve member 50 side and the pressing force of the pressing member 70 toward the opposite side to the 1 st valve member 50 side increases, the 2 nd valve member 60 moves to one side, the end 64 largely closes the opening 52, and the opening area of the opening 52 decreases. When the opening area of the opening 52 becomes smaller, the flow rate per unit time of the oil flowing through the opening 52 is restricted. Thus, the opening 52 partially closed by the end 64 of the 2 nd valve member 60 functions as a throttle added to the throttle 62.
If the opening area of the opening 52 is smaller than the cross-sectional area (minimum cross-sectional area) of the throttle 62, the flow rate per unit time of the oil flowing through the opening 52 is greatly restricted by the opening 52, and the oil flows from the 2 nd pressure chamber C2 into the 1 st pressure chamber C1 via the throttle 62. Thereby, the pressure of the oil in the 1 st pressure chamber C1 increases, and the pressure difference between the 1 st pressure chamber C1 and the 2 nd pressure chamber C2 decreases. In this way, the difference between the pressing force toward the 1 st valve member 50 side and the pressing force toward the side opposite to the 1 st valve member 50 side of the pressing member 70 due to the pressure difference becomes small, the 2 nd valve member 60 moves toward the side opposite to the 1 st valve member 50 side (the other side) and the closed area of the opening 52 closed by the end portion 64 of the 2 nd valve member 60 becomes small, and the opening area of the opening 52 becomes large. Thus, the opening 52 of the passage 51 is partially closed by the end 64, and thus the 2 nd valve member 60 stops at a position where the pressing force of pushing the 2 nd valve member 60 toward the 1 st valve member 50 side by the pressure difference generated between the 1 st pressure chamber C1 and the 2 nd pressure chamber C2 is balanced with the pressing force of the pressing member 70 toward the side opposite to the 1 st valve member 50 side. Further, the 2 nd valve member 60 may not completely stop due to a slight variation in the pressure difference generated between the 1 st pressure chamber C1 and the 2 nd pressure chamber C2, and the position thereof may slightly vary. In addition, the end 64 of the 2 nd valve member 60 may temporarily completely close the opening 52 in the middle of the movement. Thus, in the present specification, "the opening 52 is partially closed" also includes a case where the opening 52 is temporarily and completely closed.
In the example described with reference to fig. 3, 5 and 6, the throttle unit 62 functions as the throttle unit 22 in the example described with reference to fig. 2. The opening 52 and the end 64 of the 2 nd valve member 60 function as the control valve 24 in the example described with reference to fig. 2. The 1 st contact portion 53 of the 1 st valve member 50 and the 1 st step portion 33 of the 1 st housing 31 function as the check valve 28 in the example described with reference to fig. 2. Thus, the flow control valve 20 allows the flow rate of the oil from the 1 st port 30a toward the 2 nd port 30b, that is, the flow rate of the oil from the 1 st fluid pressure element E1 toward the 2 nd fluid pressure element E2 to be rapidly increased. On the other hand, the flow control valve 20 prevents the flow rate of the oil from the 2 nd port 30b toward the 1 st port 30a, that is, the flow rate of the oil from the 2 nd fluid pressure element E2 toward the 1 st fluid pressure element E1 from rapidly increasing. Therefore, in the example described with reference to fig. 1, the flow control valve 20 has a function (no-shock function) of reducing the occurrence of shock caused by a large inertial force of the front connection mechanism due to sudden stop of the hydraulic actuator 12 driven by the oil discharged from the hydraulic pump 11, which is caused by abrupt movement of the spool 14 toward one end (right end) side in the axial direction thereof.
In the present embodiment, as shown in fig. 7, even if the valve structure 40 is turned in the movement direction of the 1 st valve member 50, the housing 30 of the flow control valve 20 can house the valve structure 40. In this case, the opening 37 of the small-diameter hole 36a of the 2 nd housing 35 constitutes the 1 st step 33. When the 1 st valve member 50 and the 2 nd valve member 60 are disposed in the inverted state, the flow control valve 20 allows the flow rate of the oil from the 2 nd port 30b to the 1 st port 30a, that is, the flow rate of the oil from the 2 nd fluid pressure element E2 to the 1 st fluid pressure element E1 to be rapidly increased, contrary to the example described with reference to fig. 3, 5, and 6. On the other hand, the flow control valve 20 prevents the flow rate of the oil from the 1 st port 30a toward the 2 nd port 30b, that is, the flow rate of the oil from the 1 st fluid pressure element E1 toward the 2 nd fluid pressure element E2 from rapidly increasing. Thus, in the flow control valve 20 of the present embodiment, only by turning the 1 st valve member 50 and the 2 nd valve member 60 in the movement direction of the 1 st valve member 50, a flow control valve exhibiting a function different from that of the example described with reference to fig. 3, 5, and 6 can be obtained. In particular, in the flow control valve 20 of the present embodiment, by merely reversing the 1 st valve member 50 and the 2 nd valve member 60 in the movement direction of the 1 st valve member 50, a flow control valve capable of exhibiting a no-impact function in the direction opposite to the example described with reference to fig. 3, 5, and 6 can be obtained.
Here, the direction along the axis A is perpendicular to the central axis A, The width (outer diameter) of the small diameter portion 50a of the 1 st valve member 50 is W 1, the width (outer diameter) of the intermediate diameter portion 50b is W 2, the width (outer diameter and maximum width) of the 2 nd contact portion 65 of the 2 nd valve member 60 is W 3, the width (inner diameter) of the small diameter hole 32a of the 1 st housing 31 is W 4, and the width (inner diameter) of the small diameter hole 36a of the 2 nd housing 35 is W 5. In this embodiment, both width W 4 and width W 5 are greater than width W 1 and less than width W 2. In addition, both width W 4 and width W 5 are smaller than width W 3. Thus, even if the 1 st valve member 50 and the 2 nd valve member 60 are turned in the moving direction of the 1 st valve member 50, a flow control valve capable of exhibiting a no-impact function can be obtained. When the 1 st and 2 nd valve members 50 and 60 are inverted, the widths W 4 and W 5 are set to the same size as each other in order to obtain a flow control valve having the same characteristics as those of the flow control valve 20 before the inversion. On the other hand, when the 1 st valve member 50 and the 2 nd valve member 60 are turned over, the width W 4 and the width W 5 can be set to different sizes in order to obtain a flow control valve having characteristics different from those of the flow control valve 20 before turning over.
The flow control valve 20 of the present invention includes a housing 30 having two ports 30a, 30b and an internal space S having a shape having stepped portions 33, 38 and connected to the two ports 30a, 30b, and a valve structure 40 having a throttle portion 62, a contact portion 53 and a pressing member 70, the throttle portion 62 being provided in a flow path connecting the two ports 30a, 30b, the contact portion 53 having a surface 53a non-parallel to a moving direction, the contact portion 53 being capable of blocking the other flow path by contact with the stepped portions 33, 38, the pressing member 70 pressing the contact portion 53 so that the contact portion 53 can be brought into contact with the stepped portions 33, 38 of the housing 30, the valve structure 40 being movably accommodated in the internal space S of the housing 30.
The flow control valve 20 of the present invention includes a housing 30 having two ports 30a and 30b and an internal space S connecting the two ports 30a and 30b inside, and a valve structure 40 having a contact portion 53 and a throttle portion 62, wherein the contact portion 53 is capable of contacting one port 30a and 30b of the housing 30 in the internal space S of the housing 30, the throttle portion 62 is disposed between the one port 30a and 30b and the other port 30b and 30a, a flow path through the throttle portion 62 is formed between the two ports 30a and 30b in a state where the contact portion 53 of the valve structure 40 contacts the housing 30, and a flow path bypassing the throttle portion 62 is formed in a state where the contact portion 53 of the valve structure 40 is separated from the housing 30.
The flow control valve 20 of the present invention comprises a housing 30 having two ports 30a, 30b and an inner space S, wherein the inner space S is in the shape of a 1 st step 33 and a 2 nd step 38, and is connected to the two ports 30a, 30b, a 1 st valve member 50 which is movably accommodated in the inner space S of the housing 30, and which comprises a 1 st contact portion 53, a central passage 54 and an opening 52, wherein the 1 st contact portion 53 has a surface 53a which is not parallel to the moving direction and is capable of being brought into contact with the 1 st step 33, the central passage 54 connects one side and the other side of the 1 st contact portion 53 in the moving direction, the one side is closed, the other side is opened, the opening 52 is formed in the radial direction from the central passage 54 on one side of the 1 st contact portion 53, a 2 nd valve member 60 which is movably accommodated in the inner space S of the housing 30, and which comprises a 2 nd contact portion 65, a shaft portion 61, a hollow portion 63 and a throttle portion 62, the 2 nd contact portion 65 is capable of being brought into contact with the 2 nd step portion 38 of the housing 30, the shaft portion 61 and the other side of the hollow member 62 are capable of being brought into contact with the shaft portion 65 and the other side of the hollow member 60 in the radial direction from the moving direction, and the other side of the hollow member 60 is formed in the axial direction from the shaft portion 63, and the hollow portion 60 is capable of being pressed in the axial direction from the 2 nd contact portion 63, and the other side of the hollow portion 60.
The work machine of the present invention includes the flow control valve 20 described above.
According to the flow control valve 20 and the work machine, it is possible to switch between the flow path including the throttle 62 and the flow path bypassing the throttle 62 in a state where the 1 st contact portion 53 of the valve member 50 is in contact with the housing 30 and in a state where the 1 st contact portion 53 of the valve member 50 is separated from the housing 30. Thus, different flow control functions can be imparted to the flow control valve 20 in a state where the 1 st contact portion 53 of the valve member 50 is in contact with the housing 30 and in a state where the 1 st contact portion 53 of the valve member 50 is separated from the housing 30. In this case, since the 1 st contact portion 53 is separated from the housing 30, the flow path of the oil is instantaneously switched from the flow path including the throttle portion 62 to the flow path bypassing the throttle portion 62. Thus, the occurrence of a response delay in the flow control valve 20 can be effectively prevented. In addition, by replacing at least a part of the valve structure 40 including the valve member 50, a different flow control function can be further imparted to the flow control valve 20 without replacing the housing 30. This effectively reduces the number of replacement parts when changing the function of the flow control valve 20.
In the flow control valve 20 of the present invention, the contact portion 53 is formed at the valve member 50, the throttle portion 62 is formed at the other valve member 60, and the pressing member 70 presses the valve member 50 and the other valve member 60 so as to separate the valve member 50 and the other valve member 60 from each other.
In the flow control valve 20 of the present invention, the other valve member 60 moves so as to approach the valve member 50, whereby the opening area of the opening 52 of the flow path changes.
According to the flow control valve 20, the portion of the flow path including the throttle 62 that is partially closed by the other valve member 60 can be made to function as an additional throttle. Therefore, when it is required to greatly limit the flow rate per unit time of the fluid flowing in the fluid circuit, it is not necessary to provide the throttle portion having a very small cross-sectional dimension. Thus, the flow control valve 20 exhibiting a high flow control function can be easily manufactured. Further, since the portion (in the present embodiment, the opening 52 of the passage 51) partially closed by the other valve member 60 functions as a throttle portion whose opening area can be changed by being partially closed by the other valve member 60 (end 64), it is not necessary to form the portion as a hole having a very small cross-sectional size.
When the fluid circuit is a hydraulic circuit, the flow rate per unit time of the oil flowing through the throttle is greatly affected by the temperature of the oil. At high temperatures, the viscosity of the oil is small, but at low temperatures, the viscosity of the oil becomes large. In general, since the viscosity of oil has a large temperature dependency, when a throttle portion having a very small cross-sectional size is used, the flow rate per unit time of the oil flowing through the throttle portion increases at a high temperature, and the flow rate limiting effect decreases. In contrast, according to the flow control valve 20 of the present invention, since the orifice having a relatively large cross-sectional size can be used as the throttle 62, the flow rate per unit time of the oil flowing through the flow control valve 20 is suppressed from being affected by the temperature of the oil, and the flow rate can be controlled with high accuracy.
In the flow control valve 20 of the present invention, even if the valve structure 40 is turned in the moving direction, the housing 30 can house the valve structure 40.
According to the flow control valve 20 described above, it is possible to obtain a flow control valve that performs a different function, particularly an impact-free function in the opposite direction, by simply reversing the valve member 50 and the other valve member 60 in the moving direction of the valve member 50. This can further effectively reduce the number of replacement parts when changing the function of the flow control valve 20.

Claims (6)

1. A flow control valve, comprising:
a housing having two ports, and an inner space in the shape of a stepped portion connected to the two ports, and
A valve structure having a throttle portion provided in a1 st flow path connecting the two ports, a contact portion having a surface non-parallel to a moving direction and capable of blocking a 2 nd flow path bypassing the throttle portion by contact with the stepped portion, and a pressing member for pressing the contact portion so that the contact portion can contact with the stepped portion of the housing, the valve structure being movably accommodated in the internal space of the housing,
The contact portion is formed at the valve member, the throttle portion is formed at the other valve member,
The valve member has an opening portion constituting a part of the 1 st flow path,
By the valve member being moved relatively to the other valve member, the opening portion is partially closed by the other valve member.
2. The flow control valve of claim 1, wherein,
The pressing member presses the valve member and the other valve member in such a manner as to separate the valve member and the other valve member.
3. The flow control valve of claim 1, wherein,
The housing can receive the valve structure even if the valve structure is turned in the moving direction.
4. A flow control valve, comprising:
A housing having two ports and an internal space connecting the two ports internally, and
The valve structure includes a contact portion that is capable of contacting one port of the housing in the internal space of the housing, and a throttle portion that is disposed between the one port and the other port,
In a state where the contact portion of the valve structure is in contact with the housing, a flow path through a throttle portion is formed between the two ports,
A flow path is formed to bypass the throttle portion in a state where the contact portion of the valve structure is separated from the housing.
5. A flow control valve, comprising:
a housing having two ports, and an inner space in a shape having a1 st step portion and a2 nd step portion, connected to the two ports;
A 1 st valve member movably accommodated in the internal space of the housing, the 1 st valve member including a 1 st contact portion having a surface non-parallel to a moving direction and capable of contacting the 1 st step portion, a central passage connecting one side and the other side of the moving direction of the 1 st contact portion, the one side of the central passage being closed, the other side of the central passage being open, and an opening portion formed in a radial direction from the central passage at the one side of the 1 st contact portion;
A2 nd valve member movably accommodated in the internal space of the housing, including a2 nd contact portion contactable with the 2 nd step portion of the housing, a shaft portion integrally formed with the 2 nd contact portion and movable in the axial direction in the center passage of the 1 st valve member, a hollow portion open at one side in the movement direction of the shaft portion and closed at the other side, and a throttle portion formed in a radial direction from the hollow portion, and
A pressing member that moves the 1 st valve member and the 2 nd valve member away from each other.
6. A working machine provided with the flow control valve according to any one of claims 1 to 5.
CN202010073712.1A 2019-01-23 2020-01-22 Flow control valve and operating machinery Active CN111473011B (en)

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