Flow control valve and operating machinery

Abstract

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

Technical Field

[0001] The present invention relates to a flow control valve for controlling the flow rate of a flowing fluid and a working machine equipped with the flow control valve. Background Art

[0002] Conventionally, flow control valves for controlling the flow rate of fluid flowing in various fluid circuits are used. For example, in hydraulically driven work machines such as construction vehicles, flow control valves for controlling the flow rate of oil flowing in the hydraulic circuits are used in hydraulic circuits for supplying hydraulic oil to hydraulic actuators of the work machines and for supplying pilot pressure for operating hydraulic devices such as reversing valves.

[0003] Japanese JPH08-312801A discloses a non-shock valve, which includes: an input port; an output port; a main body; a spool inserted into a fluid chamber inside the main body in a manner that allows it to move in the length direction; a first spring that forces the spool toward the input port side; and a second spring that forces the spool toward the output port side. In this non-shock valve, if the pilot valve is set to a neutral position in order to stop the drive of the hydraulic actuator, the output of the pressure oil of the pilot valve is stopped, and the pressure on the input port side of the non-shock valve drops sharply. As a result, the pressure oil flows from the output port into the spool inner chamber on the output port side of the fluid chamber, and flows into the spool inner chamber on the input port side through the throttling communication hole. At this time, a pressure difference is generated before and after the throttling communication hole, and the spool moves toward the input port side. As a result, the opening formed by the first communication hole connecting the spool inner chamber on the input port side and the first annular groove is narrowed, and the flow of the pressure oil passing therethrough is restricted. If the pressure oil flows further, the slide valve core stops at a position where the pressure difference before and after the throttling connecting hole is balanced with the force of the second spring, the opening of the first connecting hole is adjusted, and the flow rate of the pressure oil from the output port side to the input port side is constant. Therefore, even if the output of the pressure oil of the pilot valve is suddenly stopped, the speed of the return action of the slide valve core in the control valve can be slowed down. Therefore, the impact action of the pilot valve can be buffered.

[0004] In the reversing valve disclosed in Japanese JPS55-107101A, two holes are provided in the outer wall of the housing, and throttle valves with check valves are respectively installed and fixed in these holes. The throttle valves with check valves control the oil volume by inlet throttling mode and outlet throttling mode respectively. The above-mentioned two holes are formed in the same shape and the same size as each other, and the two throttle valves with check valves can be replaced according to the purpose and use conditions. Therefore, the throttle valve with check valve disclosed in Japanese JPS55-107101A is interchangeable, and thus has the advantage of being able to meet a wide range of purposes and use conditions.

[0005] In the shockless valve disclosed in Japanese JPH08-312801A, when pressure oil is output from the pilot valve to drive the hydraulic actuator, the pressure oil flowing into the shockless valve via the input port flows into the inner chamber of the sliding valve core on the input port side through the communication path, the first annular groove, and the first communication hole of the sliding valve core, and further flows to the output port side through the throttling communication hole. If the oil passes through the throttling communication hole, a pressure difference is generated before and after the throttling communication hole. If the pressure difference is greater than the force of the first spring, the sliding valve core overcomes the force of the first spring and moves to the output port side. As a result, the first annular groove and the second annular groove are connected by the outer peripheral groove of the sliding valve core, and the pressure oil flows into the inner chamber of the sliding valve core on the output port side through the second communication hole. At this time, the shockless valve 1 is interposed between the pilot valve and the control valve, so that the action of the control valve produces a response delay. This response delay acts in a manner to alleviate the impact action of the control valve. On the other hand, if such a response delay occurs when the hydraulic actuator starts to be driven, there is a disadvantage that the operator feels that the hydraulic actuator is moving slowly, which causes a sense of discomfort.

[0006] In addition, the throttle valve with a check valve for the meter-in mode disclosed in Japanese JPS55-107101A and the throttle valve with a check valve for the meter-out mode have completely different components. When replacing the throttle valve with a check valve, the throttle valve with a check valve needs to be replaced as a whole with another throttle valve with a check valve. Therefore, the number of replacement parts increases, thereby causing the problem of increased manufacturing cost, labor and time for replacement of the throttle valve with a check valve. Summary of the invention

[0007] 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. In addition, an object of the present invention is to reduce the number of parts to be replaced when changing the function of a flow control valve.

[0008] The flow control valve of the present invention has:

[0009] a housing having: two ports; and an inner space having a stepped shape connected to the two ports; and

[0010] A valve structure, comprising: a throttling portion, which is arranged in the flow path connecting the two ports; a contact portion, which has a surface that is not parallel to the moving direction and can block the other flow path by contacting the step portion; and a pressing member, which presses the contact portion in a manner such that the contact portion can contact the step portion of the shell, and the valve structure is accommodated in the internal space of the shell in a movably manner.

[0011] In the flow control valve of the present invention, it is also possible that:

[0012] The contact portion is formed on the valve member, the throttle portion is formed on the other valve member, and the pressing member presses the valve member and the other valve member so as to move the valve member and the other valve member away from each other.

[0013] In the flow control valve of the present invention, it is also possible that:

[0014] When the other valve member moves so as to approach the valve member, the opening area of ​​the opening of the flow path changes.

[0015] In the flow control valve of the present invention, it is also possible that:

[0016] The housing can accommodate the valve structure even if the valve structure is reversed in the moving direction.

[0017] The flow control valve of the present invention has:

[0018] a housing having two ports and an internal space internally connecting the two ports; and

[0019] A valve structure having: a contact portion capable of contacting one port of the housing in the internal space of the housing; and a throttle portion arranged between the one port and another port,

[0020] In a state where the contact portion of the valve structure is in contact with the housing, a flow path is formed between the two ports via the throttle portion.

[0021] In a state where the contact portion of the valve structure is separated from the housing, a flow path that bypasses the throttle portion is formed.

[0022] The flow control valve of the present invention has:

[0023] A housing having: two ports; and an internal space having a shape having a first step portion and a second step portion, connected to the two ports;

[0024] A first valve member is movably accommodated in the internal space of the housing, and comprises: a first contact portion having a surface that is not parallel to the moving direction and can contact the first step portion; a central passage connecting one side and the other side of the moving direction of the first contact portion, the one side of the central passage being closed and the other side of the central passage being open; and an opening portion formed along a radial direction from the central passage on the one side of the first contact portion;

[0025] A second valve member is movably accommodated in the internal space of the housing, and comprises: a second contact portion capable of contacting the second step portion of the housing; a shaft portion formed integrally with the second contact portion and capable of moving along the axial direction in the central passage of the first valve member; a hollow portion, the one side of the hollow portion located in the moving direction of the shaft portion being open and the other side being closed; and a throttle portion formed radially from the hollow portion; and

[0026] A pressing member moves the first valve member and the second valve member away from each other.

[0027] A working machine according to the present invention includes the above-mentioned flow control valve.

[0028] Effects of the Invention

[0029] According to the present invention, it is possible to prevent a response delay from occurring in a flow control valve. Furthermore, according to the present invention, it is possible to reduce the number of parts to be replaced when changing the function of a flow control valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a diagram for explaining one embodiment of the present invention and is a hydraulic circuit diagram showing an example of a hydraulic circuit of a working machine in which a flow control valve is incorporated.

[0031] Figure 2 This is a hydraulic circuit diagram showing an example of a flow control valve.

[0032] Figure 3 It is a longitudinal sectional view showing an example of a flow control valve.

[0033] Figure 4 It is a perspective view showing the shape of the second contact portion of the second valve member of the flow control valve.

[0034] Figure 5 It is a diagram for explaining the operation of the flow control valve.

[0035] Figure 6 It is a diagram for explaining the operation of the flow control valve.

[0036] Figure 7 This is a longitudinal sectional view showing the flow control valve with the valve structure turned upside down.

[0037] Description of Reference Numerals

[0038] 10. Hydraulic circuit; 11. Hydraulic pump; 12. Hydraulic actuator; 13. Sliding valve; 16. Pilot pump; 17. Remote control valve; 19. Tank; 20. Flow control valve; 30. Housing; 30a. First port; 30b. Second port; 31. First housing; 33. First step portion; 35. Second housing; 40. Valve structure; 50. First valve member; 51. Passage; 52. Opening portion; 53. First contact portion; 54. Central passage; 60. Second valve member; 61. Shaft portion; 62. Throttling portion; 63. Hollow portion; 64. End portion; 65. Second contact portion; 66. Notch portion; 70. Pressing member; A. Central axis; E1. First fluid pressure element; E2. Second fluid pressure element; C1. First pressure chamber; C2. Second pressure chamber; S. Internal space DETAILED DESCRIPTION

[0039] Hereinafter, one embodiment of the present invention will be described with reference to the accompanying drawings. In addition, in the drawings attached to this specification, for the convenience of easy illustration and understanding, the scale and aspect ratio are appropriately changed and enlarged relative to the scale and aspect ratio of the actual object.

[0040] In addition, the shapes, geometric conditions and the degrees of determination thereof, such as terms such as "parallel", "orthogonal", "same", lengths, angle values, etc. used in this specification are not limited to the strict meanings, but shall be interpreted within the scope of the degree to which the same function can be expected.

[0041] Figure 1 to Figure 7 This is a diagram for explaining one embodiment of the present invention. In this embodiment, an example of a flow control valve 20 used as a so-called shockless valve in a hydraulic circuit 10 is described, but the use of the flow control valve 20 is not limited to this, and the flow control valve 20 can be configured and used at a location in various fluid circuits where the flow rate of the fluid should be controlled. Figure 1 1 is a hydraulic circuit diagram showing an example of a hydraulic circuit 10 of a working machine in which a flow control valve 20 is incorporated.

[0042] Figure 1 The hydraulic circuit 10 shown comprises: a slide valve 13, which controls the flow of working oil ejected from a hydraulic pump 11 toward a hydraulic actuator 12; a remote control valve 17, which selects the flow path of the pilot oil generated by a pilot pump 16; and a flow control valve (shockless valve) 20, which controls the flow of the pilot oil flowing between the slide valve 13 and the remote control valve 17.

[0043] The slide valve 13 has a slide valve core 14. Due to the effect of the pilot pressure, which is the pressure of the pilot oil generated by the pilot pump 16, the slide valve core 14 is moved in the axial direction (length direction) Figure 1The position of the hydraulic pump 11 (in the left and right directions) is changed, thereby continuously changing the flow rate of the hydraulic oil discharged from the hydraulic pump 11 to the hydraulic actuator 12. The pilot pump 16 is a hydraulic pump that discharges pilot oil with a constant pilot pressure at all times, and a gear pump is used as an example. In the example shown in the figure, the pilot pressure is not applied to the end of the spool 14 along the axial direction (at Figure 1 is the right end) and the other end (in Figure 1 In any case of the left end (in the left end), the spool 14 is located at the position closest to one end by the pressing force of the spring 15. If the pilot pressure acts on one end of the spool 14 via the flow path 101, the spool 14 overcomes the pressing force of the spring 15 and moves toward the other end, the flow rate of the working oil discharged from the hydraulic pump 11 to 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, the spool 14 moves toward one end, and the flow rate of the working oil decreases.

[0044] The remote control valve 17 includes an operating lever 18 operated by an operator, and selects and connects the flow path of the pilot oil generated by the pilot pump 16 from the flow path 101, the flow path 102, and the tank 19 according to the operation of the operating lever 18. When the operating lever 18 is in the neutral position, the remote control valve 17 connects the pilot pump 16 and the tank 19. When the operating lever 18 is operated toward the first operating position, the remote control valve 17 connects the pilot pump 16 and the flow path 101, and connects the flow path 102 and the tank 19. When the operating lever 18 is operated toward the second operating position different from the first operating position, the remote control valve 17 connects the pilot pump 16 and the flow path 102, and connects the flow path 101 and the tank 19.

[0045] In the illustrated hydraulic circuit 10, when the operator does not operate the operating lever 18, the operating lever 18 of the remote control valve 17 is in a neutral position, and the pilot oil generated by the pilot pump 16 is discharged to the tank 19 via the remote control valve 17. Therefore, the pilot pressure does not act on either one end or the other end of the spool 14.

[0046] When the operating lever 18 is operated by the operator toward the first operating position, the pilot oil generated by the pilot pump 16 flows toward the slide valve 13 via the remote control valve 17 and the flow path 101, and the oil from the slide valve 13 toward the remote control valve 17 via the flow path 102 is discharged to the tank 19. As a result, the pilot pressure acts on one end of the slide valve core 14, and the slide valve core 14 overcomes the pressing force of the spring 15 and moves toward the other end side. Therefore, the flow rate of the working oil discharged from the hydraulic pump 11 toward the hydraulic actuator 12 increases, and the hydraulic actuator 12 is driven in one direction. For example, the hydraulic cylinder for driving the boom of the hydraulic excavator extends, and the boom works.

[0047] When the operating lever 18 is operated by the operator toward the second operating position, the pilot oil generated by the pilot pump 16 flows toward the slide valve 13 via the remote control valve 17 and the flow path 102, and the oil from the slide valve 13 to the remote control valve 17 via the flow path 101 is discharged to the tank 19. As a result, the pilot pressure acts on the other end of the slide valve core 14, and the slide valve core 14 moves toward one end side. Therefore, the flow rate of the working oil discharged from the hydraulic pump 11 and toward the hydraulic actuator 12 is reduced, and the hydraulic actuator 12 stops.

[0048] In such a hydraulic circuit 10, there is a situation where the sliding valve core 14 is required to move quickly in one direction along the axial direction and slowly in the other direction. For example, the front connecting mechanism (boom, dipper arm and bucket) installed on a working machine such as a hydraulic excavator and driven using a hydraulic circuit has a relatively large weight. In this case, if the front connecting mechanism stops suddenly after working using the hydraulic pressure, an impact caused by the large inertial force of the front connecting mechanism occurs, and as a result, the working machine as a whole may swing greatly. The operator cannot perform the next action until the swing subsides, so the efficiency of the work using the working machine is reduced. Therefore, in Figure 1 In the hydraulic circuit 10 shown, a flow control valve (non-surge valve) 20 is provided in the middle of a flow path 101 that communicates between the remote control valve 17 and the spool valve 13 .

[0049] Figure 2 2 is a hydraulic circuit diagram for explaining an example of a flow control valve 20. In the example shown in the figure, the flow control valve 20 is arranged between the first fluid pressure element E1 and the second fluid pressure element E2, so that the fluid from the first fluid pressure element E1 to the second fluid pressure element E2 flows quickly, and the fluid from the second fluid pressure element E2 to the first fluid pressure element E1 flows slowly. Figure 1 In the case of the hydraulic circuit 10 shown, for example, the first fluid pressure element E1 is the remote control valve 17, and the second fluid pressure element E2 is the slide valve 13. However, this is not limiting, and the first fluid pressure element E1 and the second fluid pressure element E2 connected to the flow control valve 20 may also be other fluid pressure elements such as hydraulic elements and pneumatic elements.

[0050] Figure 2 The flow control valve 20 shown in the figure includes a throttle portion 22, a control valve 24 and a check valve 28. Figure 2 2 , the throttle portion 22 , the control valve 24 , the check valve 28 , and the flow paths 103 , 104 are conceptually represented according to their functions.

[0051] The throttle portion 22 is provided in the middle of the flow path 103 that communicates the first fluid pressure element E1 and the second fluid pressure element E2 , and limits the flow rate per unit time of oil (fluid) flowing through the flow path 103 .

[0052] The control valve 24 controls the flow rate per unit time of the oil flowing in 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 on the side of the first fluid pressure element E1 of the throttle portion 22 and the pressure of the oil at the position P2 on the side of the second fluid pressure element E2 of the throttle portion 22 in the flow path 103, thereby changing the flow rate per unit time of the oil flowing in the flow path 103. In the example shown in the figure, 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 the largest. In this embodiment, the opening area of ​​the opening portion 52 of the passage 51 of the first valve member 50 described later becomes the largest. 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, thereby reducing the flow rate per unit time of the oil flowing in the flow path 103. In the present embodiment, the second valve member 60 described later moves in a manner close to the first valve member 50, and the opening 52 is partially closed by the end 64 of the second valve member 60. Therefore, the control valve 24 functions as an additional throttle portion that limits the flow rate per unit time of the oil flowing in the flow path 103. In particular, the control valve 24 functions as a variable throttle valve that can continuously change the cross-sectional area of ​​the flow path 103.

[0053] A check valve 28 is provided in the middle of the flow path 104. The flow path 104 branches from a position P3 on the side of the control valve 24 on the first fluid pressure element E1 in the flow path 103, bypasses the throttle portion 22 and the control valve 24, and merges with the flow path 103 at a position P4 on the side of the second fluid pressure element E2 of the throttle portion 22. 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 first valve member 50 having the first contact portion 53 described later functions as the check valve 28. The oil flowing into the check valve 28 from the position P3 via the flow path 104 flows toward 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 via the flow path 104 is blocked by the check valve 28 and cannot flow toward the position P3.

[0054] exist Figure 2 In the flow control valve 20 shown, the oil from the first fluid pressure element E1 to the second fluid pressure element E2 flows toward the position P3 along the flow path 103. The check valve 28 allows the oil to flow from the position P3 to the position P4 via the flow path 104. The throttle 22 and the control valve 24 also allow the oil to flow from the position P3 to the position P4 via the flow path 103, and the flow rate per unit time is limited by the throttle 22. Therefore, the oil from the position P3 to the position P4 flows mainly 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 to the second fluid pressure element E2.

[0055] The oil from the second fluid pressure element E2 toward the first fluid pressure element E1 flows along the flow path 103 toward the position P4. Here, the one-way 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 portion 22. Here, the flow rate per unit time of the oil flowing in the throttle portion 22 is limited. As a result, a difference is generated between the pressure of the oil at the positions P2 and P4 on the side of the second fluid pressure element E2 of the throttle portion 22 and the pressure of the oil at the positions P1 and P3 on the side of the first fluid pressure element E1 (the control valve 24 side) of the throttle portion 22. Specifically, the pressure of the oil at the positions P2 and P4 is greater than the pressure of the oil at the positions P1 and P3. The pressure of the oil at the positions P2 and P4 is introduced into the control valve 24. As a result, 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 in the flow path 103. At this time, the control valve 24 functions as an additional throttle portion to limit the flow rate per unit time of the oil flowing through the control valve 24. That is, the flow rate per unit time of the oil whose flow rate per unit time is limited by the throttle portion 22 is further limited in the control valve 24.

[0056] When the oil flows from the first fluid pressure element E1 to the second fluid pressure element E2, the check valve 28 allows the oil to flow, so the oil quickly passes through the flow control valve 20. When the first fluid pressure element E1 is the remote control valve 17 and the second fluid pressure element E2 is the spool valve 13, the pilot oil from the remote control valve 17 to the spool valve 13 passes through the flow control valve 20 to quickly operate the spool valve 13. Therefore, the flow rate of the working oil discharged from the hydraulic pump 11 to the hydraulic actuator 12 increases quickly.

[0057] When the oil flows from the second fluid pressure element E2 to the first fluid pressure element E1, the check valve 28 does not allow the oil to flow. Therefore, the flow rate of the oil per unit time is limited by the throttle 22, and the flow rate per unit time is further limited in the control valve 24. In the case where the first fluid pressure element E1 is the remote control valve 17 and the second fluid pressure element E2 is the slide valve 13, the flow rate of the oil per unit time from the slide valve 13 to the remote control valve 17 is greatly limited by the flow control valve 20. As a result, the slide valve 13 operates at a slow speed. Therefore, the flow rate of the working oil discharged from the hydraulic pump 11 and directed to the hydraulic actuator 12 is reduced at a slow speed.

[0058] exist Figure 1 and Figure 2In the example shown, when the hydraulic oil starts to be sent to the hydraulic actuator 12, the flow rate of the hydraulic oil to the hydraulic actuator 12 can be quickly increased. As a result, when the hydraulic actuator 12 starts to be driven, it is possible to suppress the operation delay of the hydraulic actuator 12. Therefore, when the hydraulic actuator 12 starts to be driven, it is possible to prevent the operator who operates the operating lever 18 from feeling a sense of discomfort or from further unnecessary operation of the operating lever 18 in order to further operate the hydraulic actuator 12.

[0059] On the other hand, when the hydraulic oil is stopped from being delivered to the hydraulic actuator 12, the flow rate of the hydraulic oil to the hydraulic actuator 12 can be reduced at a slow speed. As a result, the hydraulic actuator 12 can be effectively prevented from suddenly stopping and causing an impact on the working machine due to the large inertial force of the front connecting mechanism. Therefore, the entire working machine is prevented from swinging greatly, and the operator can quickly perform the next action. In other words, the work efficiency of the working machine can be effectively improved.

[0060] Next, refer to Figure 3 and Figure 4 Next, an example of a specific structure of the flow control valve 20 according to the present embodiment will be described in detail. Figure 3 is a longitudinal sectional view showing an example of the flow control valve 20, Figure 4 It is a perspective view showing the shape of the second contact portion 65 of the second valve member 60 of the flow control valve 20 .

[0061] exist Figure 3In the example shown, the flow control valve 20 includes a housing 30 having two ports 30a and 30b and an internal space S having a shape having step portions 33 and 38 and connected to the two ports 30a and 30b, and a valve structure 40 held in the housing 30. In particular, the housing 30 includes two ports 30a and 30b and an internal space S having a shape having a first step portion 33 and a second step portion 38 and connected to the two ports 30a and 30b. The valve structure 40 has a throttle portion 62 provided in a first flow path (described later) connecting the two ports 30a and 30b, a first contact portion 53 having a surface 53a that is not parallel to the moving direction and can block a second flow path (described later) by contacting the step portions 33 and 38 of the housing 30, and a pressing member 70 that presses the first contact portion 53 so that the first contact portion 53 can contact the step 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 first valve member (one valve member) 50 and a second valve member (another valve member) 60 that are movably accommodated in the housing 30, and a pressing member 70 that is disposed between the first valve member 50 and the second valve member 60. In the example shown in the figure, the first contact portion 53 is formed on the first valve member 50, the throttle portion 62 is formed on the second valve member 60, and the pressing member 70 presses the first valve member 50 and the second valve member 60 so as to separate the first valve member 50 and the second valve member 60. The components of the flow control valve 20 are described below. Figure 3 In the embodiment, the direction along the central axis A of the flow control valve 20 is defined as the axial direction da, and the outer member 90 side relative to the flow control valve 20 along the axial direction da (at Figure 3 The lower side in the figure is called "one side", and the side opposite to the "one side" (in the figure) is called "the lower side". Figure 3 The upper side is called the "other side". Figure 3 In the example shown, the flow control valve 20 communicates with the first fluid pressure element E1 at one side portion thereof and communicates with the second fluid pressure element E2 at the other side portion thereof.

[0062] The housing 30 functions as a housing that divides and forms the internal space S. The housing 30 has two ports, a first port 30a and a second port 30b. In the illustrated example, the housing 30 includes: a first housing 31 having the first port 30a; and a second housing 35 having the second port 30b, which is connected to the first housing 31, and the internal space S is divided and formed by the first housing 31 and the second housing 35. The housing 30 has step portions 33 and 38 that the first contact portion 53 contacts and separates with the movement of the valve structure 40. Therefore, the housing 30 has: two ports 30a and 30b; and the internal space S, which is in a shape having the step portions 33 and 38 and is connected to the two ports 30a and 30b. By dividing the housing 30 into the first housing 31 and the second housing 35 to form the housing 30, the housing 30 can be easily manufactured. The housing 30 is formed with a first threaded portion 41, and the flow control valve 20 (housing 30) is mounted on the external member 90 by threading the first threaded portion 41 with an external threaded portion 94 formed in a recessed portion 92 of the external member 90. The housing 30 has a generally cylindrical shape, and has a generally circular shape when viewed along the axial direction da. The external member 90 is a part of any hydraulic device. The external member 90 is a member that communicates with the first fluid pressure element E1 (remote control valve 17). In the example shown in the figure, the first port 30a is communicated with the first fluid pressure element E1, and the second port 30b is communicated with the second fluid pressure element E2.

[0063] The first housing 31 includes a small diameter portion 31a and a large diameter portion 31b located on the other side of the small diameter portion 31a. The small diameter portion 31a has a relatively small diameter relative to the diameter of the large diameter portion 31b. A first threaded portion 41 is formed on one side of the outer periphery of the small diameter portion 31a. The first threaded portion 41 is composed of an external thread. The large diameter portion 31b has a relatively large diameter relative to the diameter of the small diameter portion 31a. The small diameter portion 31a and the large diameter portion 31b each have a substantially cylindrical shape.

[0064] A through hole 32 is formed inside the first housing 31 so as to penetrate from one side to the other side. In the example shown in the figure, the through hole 32 is composed of a combination of three holes (32a to 32c) having different diameters in a manner that gradually increases from one side to the other side. The hole that opens on the end surface of one side of the first housing 31 and has the smallest cross-sectional size (diameter) is set as the small-diameter hole 32a, the hole that opens on the end surface of the other side of the first housing 31 and has the largest diameter is set as the large-diameter hole 32c, and the hole that is located between the small-diameter hole 32a and the large-diameter hole 32c along the axial direction da and has a diameter between the diameter of the small-diameter hole 32a and the diameter of the large-diameter hole 32c is set as the medium-diameter hole 32b. In the example shown in the figure, the small-diameter hole 32a constitutes the first port 30a. The holes 32a to 32c are coaxially arranged with each other. A second threaded portion 42 is formed on the inner peripheral surface of the through hole 32. In particular, the second threaded portion 42 is formed on the inner peripheral surface of the large diameter hole 32c. The second threaded portion 42 is composed of an internal thread. The end portion on the other side of the small diameter hole 32a forms the first step portion 33 that contacts the first contact portion 53 described later of the first valve member 50. In addition, the middle diameter hole 32b can also be omitted. That is, the through hole 32 can also be configured to have a small diameter hole 32a and a large diameter hole 32c.

[0065] The second housing 35 is formed in a generally cylindrical shape as a whole, and is mounted on the first housing 31 at one side thereof. A third threaded portion 43 is formed on one side of the outer periphery of the second housing 35, and a fourth threaded portion 44 is formed on the other side of the outer periphery of the second housing 35. The third threaded portion 43 and the fourth threaded portion 44 are both composed of external threads. In the illustrated example, one end of the second housing 35 is located in the through hole 32 (large diameter hole 32c) of the first housing 31, and the second housing 35 is mounted on the first housing 31 by threading the third threaded portion 43 of the second housing 35 with the second threaded portion 42 of the first housing 31.

[0066] A through hole 36 is formed inside the second housing 35, which passes through from one side to the other side. The through hole 36 is composed of a combination of two holes (36a, 36b) having different diameters. The hole located on the other side and having a relatively small diameter is set as the small-diameter hole 36a, and the hole located on one side of the small-diameter hole 36a and having a relatively large diameter is set as the large-diameter hole 36b. In the example shown in the figure, the small-diameter hole 36a constitutes the second port 30b. The end of one side of the small-diameter hole 36a becomes an opening 37 opened in the large-diameter hole 36b. The large-diameter hole 36b opens on the end face of one side of the second housing 35. A second step portion 38 is formed at the position closest to the other side of the large-diameter hole 36b, and the second step portion 38 has a supporting surface for receiving the second contact portion 65 described later of the second valve member 60. The supporting surface is composed of a surface facing one side and orthogonal to the central axis A.

[0067] exist Figure 3 In the example shown, a valve structure 40 is arranged in the through hole 32 of the first housing 31 and the through hole 36 of the second housing 35. That is, a first valve member 50, a second valve member 60, and a pressing member 70 are arranged in the through holes 32 and 36. Thus, the valve structure 40 is arranged between the first port 30a and the second port 30b of the housing 30. In addition, the internal space S is divided and formed by the middle diameter hole 32b and the large diameter hole 32c of the first housing 31 and the large diameter hole 36b of the second housing 35.

[0068] A sealing member 75 is disposed between the first housing 31 and the second housing 35. In addition, a sealing member 77 is disposed between the housing 30 and the external member 90, particularly between the first housing 31 and the external member 90. The sealing members 75 and 77 are composed of, for example, O-rings, and prevent oil from leaking from between the first housing 31 and the second housing 35 or between the housing 30 and the external member 90.

[0069] The first valve member (valve member) 50 is a member that cooperates with the second valve member 60 as a reference. Figure 2 The control valve 24 described above functions and cooperates with the first step portion 33 of the first housing 31 as a reference. Figure 2 The one-way valve 28 described above functions. Figure 3 In the example shown, the first valve member 50 is composed of a combination of three parts (50a to 50c) having different cross-sectional dimensions (diameters) in a manner that increases stepwise from one side to the other side. That is, the first valve member 50 has a small diameter portion 50a, which is located at the position closest to one side along the axial direction da and has the smallest diameter; a large diameter portion 50c, which is located at the position closest to the other side and has the largest diameter; and a middle diameter portion 50b, which is located between the small diameter portion 50a and the large diameter portion 50c and has a diameter between the diameter of the small diameter portion 50a and the diameter of the large diameter portion 50c. The small diameter portion 50a, the middle diameter portion 50b, and the large diameter portion 50c all have a circular outline when viewed from the axial direction da. The large diameter portion 50c of the first valve member 50 is movable along the axial direction da while contacting the inner peripheral surface of the large diameter hole 36b of the second housing 35 through an oil film.

[0070] 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 on the side surface of the small diameter portion 50a extending along the axial direction da. The passage 51 has an opening portion 52 opened in a central passage 54 described later. The opening portion 52 is formed radially from the central passage 54 on one side of a first contact portion 53 described later. In addition, in the example shown in the figure, the passage 51 is connected to the first fluid pressure element E1 via the first port 30a (small diameter hole 32a) of the first housing 31 and the recessed portion 92 and the flow path 96 of the external member 90.

[0071] A first contact portion (contact portion) 53 is provided at a portion of the outer peripheral surface of the first valve member 50 between the small diameter portion 50a and the middle diameter portion 50b, and the first contact portion (contact portion) 53 has a seat surface that is not parallel to the moving direction of the first valve member 50, that is, the axial direction da. The seat surface extends in a direction inclined relative to both the moving direction of the first valve member 50 and the direction orthogonal to the moving direction. In more detail, the seat surface is formed by a part of a conical surface obtained by rotating a straight line that passes through a point on the central axis A that is closer to one side than the middle diameter portion 50b and is inclined relative to the central axis A around the central axis A. The small diameter portion 50a and the middle diameter portion 50b of the first valve member 50 are connected by means of the first contact portion 53. The first contact portion (contact portion) 53 is configured to be able to contact the first port 30a of the housing 30 in the internal space S of the housing 30. As described later, even if the valve structure 40 is turned over in the moving direction of the first valve member 50, the housing 30 of the flow control valve 20 can accommodate the valve structure 40. In this case, the first contact portion (contact portion) 53 is configured to be able to contact the second port 30b of the housing 30 in the internal space S of the housing 30. Therefore, the valve structure 40 includes: the first contact portion 53, which can contact the one port 30a, 30b of the housing 30 in the internal space S of the housing 30; and the throttle portion 62, which is arranged between the one port 30a, 30b and the other port 30b, 30a.

[0072] If the first valve member 50 moves to one side along the axial direction da and the first contact portion 53 contacts the first step portion 33 of the first housing 31 over the entire circumference around the central axis A, oil is prevented from flowing between the outer periphery of the first valve member 50 and the inner periphery of the through hole 32 of the first housing 31, particularly between the first contact portion 53 and the first step portion 33. On the other hand, if the first valve member 50 moves to the other side along the axial direction da and the first contact portion 53 separates from the first step portion 33, oil is allowed to flow between the outer periphery of the first valve member 50 and the inner periphery of the through hole 32 of the first housing 31.

[0073] The first valve member 50 has a central passage 54 for holding a shaft portion 61 described later of the second valve member 60. A large diameter hole 55 opened on the other side and a central passage 54 opened in the large diameter hole 55 are provided inside the first valve member 50. When viewed from the axial direction da, the central passage 54 and the large diameter hole 55 both have a circular profile. The large diameter hole 55 has a diameter larger than the diameter 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 middle diameter portion 50b, and the large diameter hole 55 extends along the central axis A inside the large diameter portion 50c. In the illustrated example, the central passage 54 connects one side and the other side of the moving direction of the first contact portion 53, and one side of the central passage 54 is closed, while the other side of the central passage 54 is open.

[0074] A hole 56 is formed in the large diameter portion 50c of the first valve member 50, which leads from the outer peripheral surface of the large diameter portion 50c to the inner peripheral surface (large diameter hole 55). The cross-sectional area of ​​the hole 56 has an area that does not substantially limit the flow rate of oil per unit time. For example, it is preferred that the cross-sectional area of ​​the hole 56 has an area that is sufficiently larger than the cross-sectional area of ​​the throttle portion 62 described later of the second valve member 60. A first support portion 57 is formed in the step portion connecting the central passage 54 and the large diameter hole 55, and the first support portion 57 is used to support the pressing member 70 and receive the pressing force of the pressing member 70. The first support portion 57 is composed of a surface orthogonal to the central axis A.

[0075] The second valve member (another valve member) 60 has a shaft portion 61 and a second contact portion 65 located on the other side of the shaft portion 61. The shaft portion 61 is formed in a generally cylindrical shape as a whole and extends along the axial direction da. In the example shown in the figure, the central axis extending in the length 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 and the second contact portion 65 are formed as one body, and the shaft portion 61 can move along the axial direction da in the central passage 54 of the first valve member 50. A hollow portion 63 is formed inside the shaft portion 61. The hollow portion 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 open, and the other side is closed. The hollow portion 63 extends along the axial direction da including the central axis A. The cross section of the hollow portion 63 orthogonal to the central axis A has a circular shape, and has the same size at each position along the axial direction da. The second valve member 60 is held in the central passage 54 of the first valve member 50 in a movable manner. In particular, the end portion 64 on one side of the second valve member 60 (the top 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 end portion 64 on one side is inserted into the central passage 54. Thus, the second valve member 60 can move in a direction toward the opening portion 52 of the passage 51 of the first valve member 50 (the direction toward one side) and a direction away from the opening portion 52 (the direction toward the other side) along the axial direction da relative to the first valve member 50. And, as the second valve member 60 moves, the opening portion 52 is partially closed by the end portion 64. In addition, since the opening portion 52 is partially closed, the opening area of ​​the opening portion 52 changes. Therefore, by the second valve member 60 moving in a manner close to the first valve member 50, the opening area of ​​the opening portion 52 of the oil flow path changes.

[0076] A throttle portion 62 communicating with the hollow portion 63 is formed on the shaft portion 61 of the second valve member 60. The throttle portion 62 is formed at a position exposed from the central passage 54 when the second valve member 60 is located at the most side position. That is, even if the second valve member 60 is located at any position within its range of movement, the throttle portion 62 is always exposed from the central passage 54. In the example shown in the figure, the throttle portion 62 extends in a direction orthogonal to the central axis A. That is, the throttle portion 62 is formed radially from the hollow portion 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 at each position along the direction in which the throttle portion 62 extends. In addition, it is not limited to this, and the throttle portion 62 may also extend in a direction inclined relative to the direction in which the central axis A extends (axial direction da) and the direction orthogonal to the central axis A. In addition, the cross section of the throttle portion 62 may also have different sizes at each position along the direction in which the throttle portion 62 extends. For example, the cross section of the throttle portion 62 may have a smaller dimension in a part of the range along the direction in which the throttle portion 62 extends than in other ranges. The minimum cross-sectional area of ​​the throttle portion 62 is set to a degree that can limit the flow rate per unit time of the oil flowing through the throttle portion 62.

[0077] The internal space S of the housing 30 is divided by the second valve member 60 into a first pressure chamber C1 including the hollow portion 63 and a second pressure chamber C2 communicating with the hollow portion 63 via the throttle portion 62. In the example shown in the figure, the first pressure chamber C1 is a space within the hollow portion 63 and the central passage 54, and the second pressure chamber C2 is a space outside the second valve member 60 in the internal space S. As described above, the opening 52 of the passage 51 opens in the central passage 54. Therefore, the opening 52 can also be said to open in the first pressure chamber C1. In the example shown in the figure, the first pressure chamber C1 communicates with the first port 30a (small diameter hole 32a) of the first housing 31 and the recessed portion 92 and the flow path 96 of the external member 90 via the opening 52.

[0078] The second 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 when viewed along the axial direction da. Therefore, the second contact portion 65 cannot enter the central passage 54. In addition, the second 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. Therefore, the second contact portion 65 can enter the large diameter hole 36b, but cannot enter the small diameter hole 36a. That is, when the second valve member 60 moves toward the other side, the second contact portion 65 contacts the second step portion 38 connecting the small diameter hole 36a and the large diameter hole 36b, and the second valve member 60 cannot move further to the other side.

[0079] The surface of the second contact portion 65 facing one side includes a second support portion 67, which is used to support the pressing member 70 and receives the pressing force of the pressing member 70. In the example shown in the figure, the pressing member 70 is a coil spring, which is arranged between the second support portion 67 and the first support portion 57 in a compressed state. Therefore, the pressing member 70 generates a pressing force in the direction in which the pressing member 70 is extended, in other words, in the direction in which the first valve member 50 and the second valve member 60 are separated due to its elastic force. The coil spring constituting the pressing member 70 is arranged in a manner surrounding the circumference of the shaft portion 61. In addition, the pressing member 70 is not limited to the coil spring, and various members that can generate a pressing force can be used.

[0080] like Figure 4 As shown, the second contact portion 65 has a notch portion 66 at the outer periphery. In the example shown in the figure, the second contact portion 65 has two notches 66 in a symmetrical manner with respect to the central axis A. When viewed from the axial direction da, the notch portion 66 extends from the outer periphery of the second contact portion 65 beyond the outline of the opening portion 37 of the small diameter hole 36a of the second housing 35 toward the inside. As a result, a gap 81 is formed between the notch portion 66 and the opening portion 37. The gap 81 has an opening area of ​​a degree that does not substantially limit the flow rate per unit time of the oil flowing in the gap 81. In the example shown in the figure, when viewed from the axial direction da, each notch portion 66 is formed by partially removing the outer periphery of the second contact portion 65 in a linear shape, but the specific shape of the notch portion 66 is not limited thereto. For example, the notch portion 66 may also be formed in a groove shape from the outer periphery of the second contact portion 65 toward the inside. In addition, the second contact portion 65 may have either one notch portion 66 or three or more notches 66. Furthermore, a through hole penetrating from one side to the other side may be provided in the second contact portion 65 instead of the notch portion 66 , and the through hole may be used as the gap 81 .

[0081] Next, refer to Figure 3 , Figure 5 as well as Figure 6 Next, the operation of the flow control valve 20 will be described.

[0082] 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 first pressure chamber C1 is equal to the pressure of the oil in the second pressure chamber C2. Figure 3As shown in the figure, the first valve member 50 is located on the side (one side) opposite to the second valve member 60 due to the pressing force of the pressing member 70. At this time, the first contact portion 53 of the first valve member 50 is pressed against the first step portion 33 of the first housing 31. In addition, the second valve member 60 is located on the side (the other side) opposite to the first valve member 50 due to the pressing force of the pressing member 70. At this time, the second contact portion 65 of the second valve member 60 is pressed against the supporting surface of the second step portion 38 of the second housing 35. In the example shown in the figure, at this time, the opening portion 52 of the passage 51 is not closed by the end portion 64 of the second valve member 60, and the opening portion 52 has an opening area of ​​a degree that does not substantially limit the flow rate per unit time of the oil flowing through the opening portion 52.

[0083] In a state where the first contact portion 53 of the first valve member 50 is in contact with the housing 30 (first step portion 33), a first flow path (flow path) including the throttle portion 62 is formed between the first port 30a and the second port 30b. Specifically, a first flow path including the passage 51, the central passage 54, the hollow portion 63, the throttle portion 62, and the gap 81 is formed between the first port 30a and the second port 30b. Therefore, in a state where the first contact portion 53 of the first valve member 50 is in contact with the housing 30, the flow path (second flow path, another flow path) bypassing the throttle portion 62 is blocked, and the oil flowing between the first port 30a and the second port 30b must pass through the throttle portion 62.

[0084] When the operating 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 first fluid pressure element E1 (remote control valve 17), the pilot pressure is introduced into the first pressure chamber C1 via the flow path 96, the recessed portion 92, the first port 30a (small diameter hole 32a) and the passage 51. At this time, the throttle portion 62 limits the flow rate per unit time of the oil flowing in the throttle portion 62. As a result, the pressure of the oil in the first pressure chamber C1 is greater than the pressure of the oil in the second pressure chamber C2. In detail, due to the flow rate limiting effect of the throttle portion 62, the rising speed of the oil pressure in the second pressure chamber C2 is slower than the rising speed of the oil pressure in the first pressure chamber C1 and the first port 30a, and a difference (pressure difference) is generated between the pressure of the oil in the first pressure chamber C1 and the first port 30a and the pressure of the oil in the second pressure chamber C2.

[0085] If the pressure difference exceeds a certain value, the force generated by the pressure difference to push the first valve member 50 toward the second valve member 60 side (the other side) is greater than the force of the pressing member 70 to push the first valve member 50 toward the side opposite to the second valve member 60 (one side), and the first valve member 50 moves toward the second valve member 60 side. As a result, the first contact portion 53 of the first valve member 50 is separated from the first step portion 33 of the first housing 31. At this time, the first port 30a and the second pressure chamber C2 are connected via the gap 83 between the first contact portion 53 and the first step portion 33. Therefore, as Figure 5 As shown, the oil flowing from the first fluid pressure element E1 to the first port 30a flows toward the second fluid pressure element E2 through the gap 83, the hole 56, the large diameter hole 55, the gap 81 and the second port 30b (the small diameter hole 36a) in sequence.

[0086] When the first contact portion 53 of the first valve member 50 is separated from the first step portion 33 of the first housing 31, oil quickly flows from the first port 30a to the second pressure chamber C2 via the gap 83, and the difference (pressure difference) between the pressure of the oil in the first pressure chamber C1 and the first port 30a and the pressure of the oil in the second pressure chamber C2 becomes smaller. As the pressure difference becomes smaller, the force that pushes the first valve member 50 toward the second valve member 60 becomes smaller, and the first valve member 50 is pushed back toward the side opposite to the second valve member 60 by the pressing force of the pressing member 70. At this time, as the gap 83 becomes smaller, a new pressure difference is generated between the first pressure chamber C1 and the first port 30a and the second pressure chamber C2, and thus, the first valve member 50 overcomes the pressing force of the pressing member 70 and is pushed toward the second valve member 60. Therefore, the first valve member 50 stops at a position where the pressing force of the pressing member 70, which pushes the first valve member 50 to the side opposite to the second valve member 60, is balanced with the pressing force of the first valve member 50 to the other side caused by the pressure difference generated between the first pressure chamber C1 and the first port 30a and the second pressure chamber C2. In addition, due to a slight change in the pressure difference generated between the first pressure chamber C1 and the first port 30a and the second pressure chamber C2, the first valve member 50 may not stop completely and its position may change slightly.

[0087] In a state where the first contact portion 53 of the first valve member 50 is separated from the housing 30 (first step portion 33), a second flow path (another flow path) that bypasses the throttle portion 62 is formed between the first port 30a and the second port 30b. Specifically, a second flow path including the gap 83, the hole 56, the large-diameter hole 55, and the gap 81 is formed between the first port 30a and the second port 30b. Therefore, in a state where the first contact portion 53 of the first valve member 50 is separated from the housing 30, most of the oil flowing between the first port 30a and the second port 30b flows without passing through the throttle portion 62. In addition, even in this case, a part of the oil flowing between the first port 30a and the second port 30b can pass through the throttle portion 62.

[0088] When the operating lever 18 of the remote control valve 17 is operated by the operator and the first pressure chamber C1 and the first port 30a are connected to the tank 19 via the recess 92, the flow path 96 and the first fluid pressure element E1 (remote control valve 17), the pressure difference between the first pressure chamber C1 and the first port 30a and the second pressure chamber C2 is sharply reduced. That is, the pressing force that pushes the first valve member 50 toward the second valve member 60 side is sharply reduced. As a result, the first valve member 50 moves to the side opposite to the second valve member 60 due to the pressing force of the pressing member 70, and the first contact portion 53 of the first valve member 50 is pressed against the first step portion 33 of the first housing 31, and the gap 83 is closed. Therefore, the first pressure chamber C1 and the second pressure chamber C2 are connected to each other only by the throttle portion 62. As a result, the pressure of the oil in the second pressure chamber C2 is greater than the pressure of the oil in the first pressure chamber C1. Specifically, due to the flow restriction effect of the throttle portion 62, the pressure drop rate of the oil in the second pressure chamber C2 is slower than that of the oil in the first pressure chamber C1, and a difference (pressure difference) is generated between the pressure of the oil in the first pressure chamber C1 and the pressure of the oil in the second pressure chamber C2. Figure 6 As shown, the second valve member 60 overcomes the pressing force of the pressing member 70 and moves toward the first valve member 50 side (one side).

[0089] The flow path including the throttle portion 62 is partially closed by the second valve member 60 moving in a manner close to the first valve member 50. Specifically, as the second valve member 60 moves, the opening portion 52 of the passage 51 is partially closed by the end portion 64 of the second valve member 60. At this time, as the pressure difference between the first pressure chamber C1 and the second pressure chamber C2 increases, the difference between the pressing force toward the first valve member 50 side caused by the pressure difference and the pressing force of the pressing member 70 toward the side opposite to the first valve member 50 side increases, the second valve member 60 moves to one side and the end portion 64 largely closes the opening portion 52, and the opening area of ​​the opening portion 52 decreases. If the opening area of ​​the opening portion 52 decreases, the flow rate per unit time of the oil flowing in the opening portion 52 is limited. Therefore, the opening portion 52 partially closed by the end portion 64 of the second valve member 60 functions as a throttle portion added to the throttle portion 62.

[0090] 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 limited by the opening 52, while the oil flows from the second pressure chamber C2 into the first pressure chamber C1 via the throttle 62. As a result, the pressure of the oil in the first pressure chamber C1 rises, and the pressure difference between the first pressure chamber C1 and the second pressure chamber C2 decreases. In this way, the difference between the pressing force toward the first valve member 50 side caused by the pressure difference and the pressing force of the pressing member 70 toward the side opposite to the first valve member 50 side decreases, and the closed area of ​​the opening 52 closed by the end 64 of the second valve member 60 when the second valve member 60 moves to the side opposite to the first valve member 50 side (the other side) decreases, and the opening area of ​​the opening 52 increases. Therefore, the opening 52 of the passage 51 is partially closed by the end 64, and thus the second valve member 60 stops at a position where the pressing force of the second valve member 60 to the first valve member 50 side caused by the pressure difference between the first pressure chamber C1 and the second pressure chamber C2 is balanced with the pressing force of the pressing member 70 toward the side opposite to the first valve member 50 side. In addition, due to a slight change in the pressure difference between the first pressure chamber C1 and the second pressure chamber C2, the second valve member 60 may not stop completely and its position may change slightly. In addition, the end 64 of the second valve member 60 may temporarily completely close the opening 52 in the middle of its movement. Therefore, in this specification, "the opening 52 is partially closed" also includes the case where the opening 52 is temporarily completely closed.

[0091] In reference Figure 3 , Figure 5 as well as Figure 6 In the example described above, the throttle portion 62 plays a role of reference Figure 2The function of the throttle portion 22 in the example described is described. In addition, the opening 52 and the end 64 of the second valve member 60 play a role in reference to Figure 2 The first contact portion 53 of the first valve member 50 and the first step portion 33 of the first housing 31 play a role in reference to the control valve 24 in the example described. Figure 2 The function of the check valve 28 in the example described is explained. Thus, the flow control valve 20 allows the oil flow from the first port 30a to the second port 30b, that is, the oil flow from the first fluid pressure element E1 to the second fluid pressure element E2 to increase rapidly. On the other hand, the flow control valve 20 prevents the oil flow from the second port 30b to the first port 30a, that is, the oil flow from the second fluid pressure element E2 to the first fluid pressure element E1 from increasing rapidly. Therefore, in reference to Figure 1 In the example described, the flow control valve 20 performs the function of reducing the occurrence of the following impact (non-impact function), which is an impact caused by the large inertia force of the front connecting mechanism due to the sudden movement of the sliding valve core 14 toward one end (right end) along its axial direction and the sudden stop of the hydraulic actuator 12 driven by the oil ejected from the hydraulic pump 11.

[0092] In this embodiment, if Figure 7 As shown, even if the valve structure 40 is turned over in the moving direction of the first valve member 50, the housing 30 of the flow control valve 20 can accommodate the valve structure 40. In this case, the opening 37 of the small-diameter hole 36a of the second housing 35 constitutes the first step 33. When the first valve member 50 and the second valve member 60 are turned over, the valve structure 40 is not moved. Figure 3 , Figure 5 as well as Figure 6 On the contrary to the example described above, the flow control valve 20 allows the oil flow from the second port 30b to the first port 30a, that is, the oil flow from the second fluid pressure element E2 to the first fluid pressure element E1 to increase rapidly. On the other hand, the flow control valve 20 prevents the oil flow from the first port 30a to the second port 30b, that is, the oil flow from the first fluid pressure element E1 to the second fluid pressure element E2 from increasing rapidly. Therefore, in the flow control valve 20 of the present embodiment, the first valve member 50 and the second valve member 60 can be reversed in the moving direction of the first valve member 50 to obtain the same effect as that of the reference. Figure 3 , Figure 5 as well as Figure 6 In particular, in the flow control valve 20 of the present embodiment, by simply flipping the first valve member 50 and the second valve member 60 in the moving direction of the first valve member 50, a flow control valve that can move in the same direction as the reference valve can be obtained. Figure 3 , Figure 5 as well as Figure 6 The example described above is a flow control valve that performs a shock-free function in the opposite direction.

[0093] Here, the width (outer diameter) of the small diameter portion 50a of the first valve member 50 along the direction orthogonal to the central axis A is set to W1, the width (outer diameter) of the middle diameter portion 50b is set to W2, the width (outer diameter and maximum width) of the second contact portion 65 of the second valve member 60 is set to W3, the width (inner diameter) of the small diameter hole 32a of the first housing 31 is set to W4, and the width (inner diameter) of the small diameter hole 36a of the second housing 35 is set to W5. In this embodiment, the width W4 and the width W5 are both larger than the width W1 and smaller than the width W2. In addition, the width W4 and the width W5 are both smaller than the width W3. Thus, even if the first valve member 50 and the second valve member 60 are turned over in the moving direction of the first valve member 50, a flow control valve capable of exerting a non-impact function can be obtained. When the first valve member 50 and the second valve member 60 are reversed, the width W4 and the width W5 are set to be equal to each other in order to obtain a flow control valve having the same characteristics as the flow control valve 20 before the reverse. On the other hand, when the first valve member 50 and the second valve member 60 are reversed, the width W4 and the width W5 can be set to be different sizes in order to obtain a flow control valve having characteristics different from the flow control valve 20 before the reverse.

[0094] The flow control valve 20 of the present invention comprises: a shell 30, which has two ports 30a, 30b and an internal space S, the internal space S is shaped with steps 33, 38 and is connected to the two ports 30a, 30b; and a valve structure 40, which has a throttling portion 62, a contact portion 53 and a pressing member 70, the throttling portion 62 is arranged in the flow path connecting the two ports 30a, 30b, the contact portion 53 has a surface 53a that is not parallel to the moving direction, and can block another flow path by contacting the steps 33, 38, the pressing member 70 presses the contact portion 53 in a manner that allows the contact portion 53 to contact the steps 33, 38 of the shell 30, and the valve structure 40 is accommodated in the internal space S of the shell 30 in a movable manner.

[0095] The flow control valve 20 of the present invention comprises: a housing 30 having two ports 30a, 30b and an internal space S connecting the two ports 30a, 30b internally; and a valve structure 40 having a contact portion 53 and a throttling portion 62, wherein the contact portion 53 can contact one port 30a, 30b of the housing 30 in the internal space S of the housing 30, and the throttling portion 62 is arranged between the one port 30a, 30b and the other port 30b, 30a, and when the contact portion 53 of the valve structure 40 is in contact with the housing 30, a flow path passing through the throttling portion 62 is formed between the two ports 30a, 30b, and when the contact portion 53 of the valve structure 40 is separated from the housing 30, a flow path bypassing the throttling portion 62 is formed.

[0096] The flow control valve 20 of the present invention comprises: a housing 30 having two ports 30a, 30b and an internal space S, wherein the internal space S is shaped to have a first step portion 33 and a second step portion 38 and is connected to the two ports 30a, 30b; a first valve member 50, which is movably accommodated in the internal space S of the housing 30, and comprises a first contact portion 53, a central passage 54 and an opening portion 52, wherein the first contact portion 53 has a surface 53a which is not parallel to the moving direction and can contact the first step portion 33, and the central passage 54 connects one side and the other side of the moving direction of the first contact portion 53, wherein the one side is closed and the other side is open, and the opening portion 52 is located at the first contact portion 53. 53 is formed radially from the central passage 54 on one side; a second valve member 60, which is movably accommodated in the internal space S of the shell 30, and has a second contact portion 65, a shaft portion 61, a hollow portion 63 and a throttling portion 62, the second contact portion 65 can contact the second step portion 38 of the shell 30, the shaft portion 61 and the second contact portion 65 are formed as a whole, and can move along the axial direction da in the central passage 54 of the first valve member 50, one side of the hollow portion 63 located in the moving direction of the shaft portion 61 is open, and the other side is closed, and the throttling portion 62 is formed radially from the hollow portion 63; and a pressing member 70, which keeps the first valve member 50 and the second valve member 60 away from each other.

[0097] The working machine of the present invention includes the above-mentioned flow control valve 20 .

[0098] According to such a flow control valve 20 and a working machine, the flow path including the throttle portion 62 and the flow path bypassing the throttle portion 62 can be switched between the state where the first contact portion 53 of the valve member 50 is in contact with the housing 30 and the state where the first contact portion 53 of the valve member 50 is separated from the housing 30. Therefore, different flow control functions can be given to the flow control valve 20 in the state where the first contact portion 53 of the valve member 50 is in contact with the housing 30 and the state where the first contact portion 53 of the valve member 50 is separated from the housing 30. In this case, since the first 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. Therefore, it is possible to effectively prevent the response delay from occurring in the flow control valve 20. In addition, by replacing at least a part of the valve structure 40 including the valve member 50, it is possible to further give different flow control functions to the flow control valve 20 without replacing the housing 30. This can effectively reduce the number of parts to be replaced when changing the function of the flow control valve 20 .

[0099] In the flow control valve 20 of the present invention, the contact portion 53 is formed on the valve member 50 , the throttle portion 62 is formed on 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 them.

[0100] In addition, in the flow control valve 20 of the present invention, the opening area of ​​the opening portion 52 of the flow path changes as the other valve member 60 moves so as to approach the valve member 50 .

[0101] According to such a flow control valve 20, the portion of the flow path including the throttle portion 62 that is partially closed by another valve member 60 can function as an additional throttle portion. Therefore, in the case where it is required to significantly limit the flow rate per unit time of the fluid flowing in the fluid circuit, there is no need to provide a throttle portion with an extremely small cross-sectional size. As a result, it is possible to easily manufacture a flow control valve 20 that exerts a high flow control function. In addition, the portion partially closed by another valve member 60 (in this embodiment, the opening portion 52 of the passage 51) functions as a throttle portion whose opening area can be changed by being partially closed by another valve member 60 (end portion 64), and therefore, it is not necessary to form the portion as a hole with an extremely small cross-sectional size.

[0102] In the case where the fluid circuit is a hydraulic circuit, the flow rate per unit time of the oil flowing in the throttle section 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 increases. Generally speaking, the viscosity of the oil has a large temperature dependence. Therefore, when a throttle section with an extremely small cross-sectional size is used, at high temperatures, the flow rate per unit time of the oil flowing in the throttle section increases, and the flow restriction effect becomes smaller. On the other hand, at low temperatures, the flow rate per unit time of the oil flowing in the throttle section becomes extremely small, and high-precision flow control becomes difficult. In contrast, according to the flow control valve 20 of the present invention, a hole with a relatively large cross-sectional size can be used as the throttle section 62, thereby suppressing the flow rate per unit time of the oil flowing in the flow control valve 20 from being affected by the temperature of the oil, and high-precision flow control can be performed.

[0103] In the flow control valve 20 of the present invention, even if the valve structure 40 is reversed in the moving direction, the housing 30 can accommodate the valve structure 40 .

[0104] According to such a flow control valve 20, a flow control valve having different functions, especially a non-impact function in the opposite direction, can be obtained simply by flipping the valve member 50 and the other valve member 60 in the moving direction of the valve member 50. Thus, the number of parts to be replaced when changing the function of the flow control valve 20 can be further effectively reduced.

Claims

1. A flow control valve comprising: a housing having: two ports; and an inner space having a stepped shape connected to the two ports; and The valve structure comprises: a throttling portion provided in a first flow path connecting the two ports; a contact portion having a surface which is not parallel to a moving direction and which can block a second flow path bypassing the throttling portion by contacting the step portion; and a pressing member which presses the contact portion in a manner that the contact portion can contact the step portion of the housing, and the valve structure is movably accommodated in the internal space of the housing. The contact portion is formed on a valve member, and the throttle portion is formed on another valve member. The valve member has an opening portion constituting a portion of the first flow path, The opening is partially closed by the other valve member due to the relative movement of the valve member and the other valve member.

2. The flow control valve according to claim 1, wherein: The pressing member presses the valve member and the other valve member so as to move the valve member and the other valve member away from each other.

3. The flow control valve according to claim 1, wherein: The housing can accommodate the valve structure even if the valve structure is reversed in the moving direction.

4. A flow control valve comprising: a housing having two ports and an internal space internally connecting the two ports; and A valve structure having: a contact portion capable of contacting one port of the housing in the internal space of the housing; and a throttle portion disposed between the one port and another port. In a state where the contact portion of the valve structure is in contact with the housing, a flow path is formed between the two ports via the throttle portion. In a state where the contact portion of the valve structure is separated from the housing, a flow path that bypasses the throttle portion is formed.

5. A flow control valve comprising: A housing having: two ports; and an internal space having a shape having a first step portion and a second step portion, connected to the two ports; A first valve member is movably accommodated in the internal space of the housing, and comprises: a first contact portion having a surface that is not parallel to the moving direction and can contact the first step portion; a central passage connecting one side and the other side of the moving direction of the first contact portion, the one side of the central passage being closed and the other side of the central passage being open; and an opening portion formed along a radial direction from the central passage on the one side of the first contact portion; A second valve member is movably accommodated in the internal space of the housing, and comprises: a second contact portion capable of contacting the second step portion of the housing; a shaft portion formed integrally with the second contact portion and capable of moving along the axial direction in the central passage of the first valve member; a hollow portion, the one side of the hollow portion located in the moving direction of the shaft portion being open and the other side being closed; and a throttle portion formed radially from the hollow portion; and A pressing member moves the first valve member and the second valve member away from each other. 6 . A working machine comprising the flow control valve according to claim 1 .

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