Flow control valve

Abstract

To provide a flow control valve that can suppress the generation of abnormal noise without causing multiple flows to collide at the center of the flow path. [Solution] A flow control valve 1 having a first port 1a and a second port 1b, wherein the flow from the first port 1a to the second port 1b is free flow and the flow from the second port 1b to the first port 1a is controlled flow, comprising: flow paths 11, 12 connecting the first port 1a and the second port 1b; a valve body 20 housed in the flow path 12 so as to be movable along the flow path 12; and a valve seat 13 provided in the flow paths 11, 12 on which the valve body 20 sits when fluid flows from the second port 1b to the first port 1a, wherein a throttle 24 is provided on the valve body 20 that connects the flow paths 11, 12 when the valve body 20 is seated on the valve seat 13, and when fluid flows from the second port 1b to the first port 1a, the fluid flowing out of the throttle 24 hits the wall surface 11a of the flow path 11.

Description

Technical Field

[0001] The present invention relates to a flow control valve for controlling the flow rate of a fluid.

Background Art

[0002] In a hydraulic device operated by hydraulic pressure, a flow control valve for controlling the flow rate of the working fluid is used to control the operation of an actuator. Among them, a flow control valve called a so-called slow return valve is known, which allows free flow in one direction while allowing a controlled flow with a fixed throttle in the reverse direction.

[0003] Conventional flow control valves are known to have a problem of generating abnormal noise under certain usage conditions when the fluid is flowing in a controlled flow. The cause of this abnormal noise is considered to be cavitation generated by the fluid flowing out vigorously from the throttle.

[0004] The flow control valve disclosed in Patent Document 1 is configured to provide a radial groove at the tip of a poppet, which is a valve body, and to cause the flow flowing out from this groove to collide at the center of the flow path in order to prevent the generation of abnormal noise. The flow control valve disclosed in this Patent Document 1 suppresses the generation of abnormal noise by having this configuration.

[0005] However, in order to cause the flows ejected from each groove to collide at the center of the flow path as in Patent Document 1, it was necessary for each groove to be accurately arranged radially in the poppet.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] In view of the above problems, the present invention aims to provide a flow control valve that can suppress the generation of abnormal noise without causing multiple flows to collide at the center of the flow path. [Means for solving the problem]

[0008] The flow control valve according to the present invention is a flow control valve having a first port and a second port, wherein the flow from the first port to the second port is free flow and the flow from the second port to the first port is controlled flow, comprising a flow path connecting the first port and the second port, a valve body housed in the flow path so as to be movable along the flow path, and a valve seat provided in the flow path on which the valve body sits when fluid flows from the second port to the first port, wherein a throttling is provided on the valve body that connects the flow path when the valve body is seated on the valve seat, and when fluid flows from the second port to the first port, the fluid flowing out of the throttling strikes the wall surface of the flow path.

[0009] Another flow control valve according to the present invention is characterized in that the valve body is provided with a groove, and when the valve body is seated on the valve seat, the groove constitutes the throttle.

[0010] Another flow control valve according to the present invention is characterized in that one of the grooves is provided on the valve body.

[0011] Another flow control valve according to the present invention is characterized in that the direction in which the groove advances and the direction of the flow path are in a twisted position relationship.

[0012] Another flow control valve according to the present invention is characterized in that the throttle is formed from a through hole provided in the valve body. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a flow control valve that can suppress the generation of abnormal noise without causing multiple flows to collide at the center of the flow path. [Brief explanation of the drawing]

[0014] [Figure 1] This is a longitudinal cross-sectional view of a flow control valve according to the first embodiment of the present invention, where (a) is a diagram showing the free flow state and (b) is a diagram showing the controlled flow state. [Figure 2] This figure shows the valve body of a flow control valve according to the first embodiment of the present invention, where (a) is a vertical cross-sectional view, (b) is a view taken along the arrow AA in (a), and (c) is a view taken along the arrow BB in (a). [Figure 3] This is a schematic longitudinal cross-sectional view showing the fluid flow out of the throttle when the fluid flows from the second port to the first port in a flow control valve according to the first embodiment of the present invention. [Figure 4] This figure shows a partially enlarged view of the area near the tip of the valve body of the flow control valve according to the second embodiment of the present invention, as seen in the same manner as in Figure 2(c). [Figure 5] This is a longitudinal cross-sectional view showing a partially enlarged view of the area near the tip of the valve body of a flow control valve according to a third embodiment of the present invention. [Modes for carrying out the invention]

[0015] Next, embodiments of a flow control valve to which the present invention is applied will be described with reference to the drawings. The embodiments described below are preferred embodiments of the present invention and therefore have various technically preferable limitations. However, the scope of the present invention is not limited to these embodiments unless otherwise specified in the following description.

[0016] <First Embodiment> A flow control valve according to the first embodiment of the present invention will be described with reference to Figures 1 to 3. Figure 1 is a longitudinal cross-sectional view of the flow control valve according to the first embodiment of the present invention, where (a) is a diagram showing the free flow state and (b) is a diagram showing the controlled flow state. Figure 2 is a diagram showing the valve body of the flow control valve according to the first embodiment of the present invention, where (a) is a longitudinal cross-sectional view, (b) is a view of the arrow AA in (a), and (c) is a view of the arrow BB in (a). Figure 3 is a longitudinal cross-sectional view schematically showing the fluid flow out of the throttle when the fluid flows from the second port to the first port in the flow control valve according to the first embodiment of the present invention. In this description, a longitudinal cross-section means a cross-section passing through a center line extending in the longitudinal direction.

[0017] The flow control valve 1 according to this embodiment has a valve body 10 as shown in Figure 1. The valve body 10 has a first port 1a and a second port 1b through which fluid flows in and out, and the first port 1a and the second port 1b are arranged opposite each other. The valve body 10 also has a first flow path 11 connected to the first port 1a and a second flow path 12 connected to the second port 1b. The first flow path 11 and the second flow path 12 are concentric and in communication, forming a flow path that connects the first port 1a and the second port 1b.

[0018] A valve body 20 is housed within the second flow path 12, and the valve body 20 is movable along the second flow path 12. As shown in Figure 2, the valve body 20 is formed in a cylindrical shape overall, and has a small-diameter portion 20a and a large-diameter portion 20b. The large-diameter portion 20b of the valve body 20 is fitted into the second flow path 12 and is configured to move along the second flow path 12. A tapered portion 23 forming a conical surface is formed on the tip portion 20c of the valve body 20 that faces the first port 1a. A communication flow path 21 is provided inside the valve body 20, and a communication hole 22 connecting the internal communication flow path 21 to the outside is provided in the small-diameter portion 20a. In this embodiment, four communication holes 22 are provided along the circumferential direction, but the number can be set arbitrarily. A throttling is formed on the tip portion 20c of the valve body 20, which will be described later.

[0019] A valve seat 13 is provided at the boundary between the first flow path 11 and the second flow path 12. In the present embodiment, the diameter of the second flow path 12 is set larger than the diameter of the first flow path 11, and the valve seat 13 is formed by an annular step between the first flow path 11 and the second flow path 12. In the present embodiment, the valve body 20 is given an elastic force toward the valve seat 13 by a spring 30, and in a state where no external force is acting, the valve body 20 is seated on the valve seat 13. The spring 30 is a coil spring, and a spring holding portion 14 for holding the end portion of the spring 30 is provided on the valve box 10 as shown in FIG. 1. The elastic force applied by the spring 30 can be arbitrarily set. In a state where the valve body 20 is seated on the valve seat 13, the tapered portion 23 of the valve body 20 is in close contact with the edge of the valve seat 13. The taper angle α of the tapered portion 23 can be arbitrarily set, and 30° to 60° is preferable, but the taper angle α in the present embodiment is 45° (see FIG. 2).

[0020] When the fluid flows from the first port 1a to the second port 1b, as shown in FIG. 1(a), the valve body 20 receives a force toward the second port 1b and moves away from the valve seat 13 against the elastic force of the spring 30 and moves toward the second port 1b. At this time, a large gap is generated between the valve body 20 and the valve seat 13. The fluid flowing from the first port 1a passes through the gap and enters the second flow path 12, passes through the communication hole 22 and the communication flow path 21 of the valve body 20, and reaches the second port 1b. The flow in this state is a free flow without controlling the flow rate.

[0021] When the fluid flows from the second port 1b to the first port 1a, as shown in FIG. 1(b), the valve body 20 receives a force toward the first port 1a and also receives the elastic force of the spring 30 and seats on the valve seat 13. As will be described later, a throttle is formed at the tip portion 20c of the valve body 20. When the valve body 20 seats on the valve seat 13, the second flow path 12 and the first flow path 11 communicate with each other through this throttle. The fluid flowing from the second port 1b passes through the communication flow path 21 and the communication hole 22 of the valve body 20, passes through the throttle provided in the valve body 20, enters the first flow path 11, and reaches the first port 1a. The flow in this state is a control flow for controlling the flow rate.

[0022] Next, the throttle of the valve body 20 in the present embodiment will be described based on FIG. 2. As described above, the valve body 20 is provided with a conical tapered portion 23. And the valve body 20 is provided with a single groove 24 formed by digging a part of the tapered portion 23 in a rib shape. As shown in FIG. 2(a), the groove 24 is located on the longitudinal section of the valve body 20. As shown in FIG. 2(a), the bottom 24a of the groove 24 extends parallel to the taper of the tapered portion 23, and as shown in FIG. 2(b), the extension line of the groove 24 passes through the center of the valve body 20 (that is, the center of the flow path). When the valve body 20 seats on the valve seat 13 as shown in FIG. 1(b), only the groove 24 communicates the first flow path 11 and the second flow path 12, and the groove 24 functions as a throttle. The flow rate of the control flow can be adjusted by setting the shape and cross-sectional area of the groove 24.

[0023] Next, the action of the groove 24 functioning as a throttle will be described based on FIG. 3. FIG. 3 schematically shows a state in which fluid is flowing as a control flow from the second port 1b toward the first port 1a. Note that both the first flow path 11 and the second flow path 12 are filled with fluid. In this state, the valve body 20 is seated on the valve seat 13, and the fluid in the second flow path 12 flows out through the groove 24 of the valve body 20 and into the first flow path 11. Since the bottom 24a of the groove 24 extends along the taper angle (45° in the present embodiment) of the tapered portion 23, it proceeds as shown by the dotted arrow in FIG. 3, passes through the center line of the first flow path 11, and hits the wall surface 11a of the first flow path 11. The fluid flowing out from the groove 24 into the first flow path 11 has a higher speed than the surrounding fluid, so cavitation may occur depending on the conditions. However, when the fluid reaches the wall surface 11a, its speed decreases, so the cavitation subsides. That is, if the fluid flowing out from the throttle groove 24 hits the wall surface 11a, the length of the high-speed region of the fluid becomes shorter, so the region where cavitation occurs also becomes smaller, and the generation of abnormal noise is suppressed.

[0024] In this embodiment, the bottom portion 24a of the groove 24 was configured to be parallel to the tapered portion 23, but the angle of the bottom portion 24a can be set arbitrarily. By setting the angle of the bottom portion 24a, the position of the wall surface 11a that the fluid flowing out of the groove 24 hits can be adjusted, that is, the length of the high-speed fluid region can be adjusted.

[0025] <Second Embodiment> Next, a flow control valve according to the second embodiment of the present invention will be described with reference to Figure 4. Figure 4 is a partially enlarged view of the area near the tip of the valve body of the flow control valve according to the second embodiment of the present invention, as viewed in the same manner as in Figure 2(c).

[0026] The difference between this embodiment and the first embodiment lies in the configuration of the grooves provided in the valve body 20. The other configurations are the same as in the first embodiment. In this embodiment, the valve body 20 is provided with a conical tapered portion 23, and a groove 25 is provided which is formed by carving a groove-like section into a part of the tapered portion 23. Unlike the first embodiment, the groove 25 is not located on the longitudinal cross-section of the valve body 20, but is inclined at an angle β with respect to the centerline of the valve body 20 in a side view, as shown in Figure 4. That is, the extension of the direction in which the groove 25 advances and the centerline of the valve body 20 (i.e., the centerline of the flow path, the direction of the flow path) do not intersect, but are in a twisted positional relationship. The angle β can be set arbitrarily, but in this embodiment, the angle β is set to 15°.

[0027] In the flow control valve according to this embodiment, when the fluid is flowing as a controlled flow from the second port 1b to the first port 1a, the groove 25 constitutes a throttling, similar to the first embodiment. That is, the flow that passes through the groove 25 and flows out into the first flow path 11 hits the wall surface 11a of the first flow path 11. Therefore, similar to the first embodiment, the length of the high-speed region of the fluid is shortened, so the region where cavitation occurs is also reduced, and the generation of abnormal noise is suppressed.

[0028] However, unlike the first embodiment, the flow that passes through the groove 25 and flows out into the first flow channel 11 does not pass through the centerline of the first flow channel 11. Therefore, if multiple grooves 25 are provided around the centerline of the valve body 20 at a predetermined circumferential angle, the flow that flows out from each groove 25 during controlled flow will hit the wall surface 11a of the first flow channel 11 without colliding with each other. Consequently, in this embodiment, it is possible to provide multiple throttles for the controlled flow, thus increasing the degree of freedom in adjusting the flow rate.

[0029] <Third Embodiment> Next, a flow control valve according to the third embodiment of the present invention will be described with reference to Figure 5. Figure 5 is a longitudinal cross-sectional view showing a partially enlarged view of the area near the tip of the valve body of the flow control valve according to the third embodiment of the present invention.

[0030] The difference between this embodiment and the first embodiment lies in the configuration of the throttling provided in the valve body 20. The other configurations are the same as in the first embodiment. In this embodiment, as shown in Figure 5, the valve body 20 is provided with a throttling hole 26 at its tip portion 20c that connects the communication passage 21 to the outside. When the valve body 20 is seated on the valve seat 13, the only thing connecting the first passage 11 and the second passage 12 is the throttling hole 26, and this throttling hole 26 constitutes the throttling.

[0031] As shown in Figure 5, the direction in which the throttling hole 26 extends is inclined at an angle γ from the center line of the valve body 20 in a longitudinal cross-sectional view. The angle γ can be set arbitrarily, but in this embodiment it is set to 30°. Therefore, in the flow control valve according to this embodiment, when the fluid is flowing as a controlled flow from the second port 1b to the first port 1a, the flow that passes through the throttling hole 26 and flows out into the first flow path 11 hits the wall surface 11a of the first flow path 11. Therefore, similar to the first embodiment, the length of the high-speed region of the fluid is shortened, so the region in which cavitation occurs is also reduced, and the generation of abnormal noise is suppressed.

[0032] Furthermore, the angle in the direction in which the aperture hole 26 extends can be set arbitrarily. By setting the angle in the direction in which the aperture hole 26 extends, the position of the wall surface 11a that the fluid flowing out of the aperture hole 26 strikes can be adjusted, that is, the length of the high-speed region of the fluid can be adjusted.

[0033] <Variation> In the embodiment described above, the valve body 20 was subjected to an elastic force toward the valve seat 13 by the spring 30, but it is also possible to omit the spring 30. Even when the spring 30 is omitted, when the fluid flows from the first port 1a to the second port 1b, the valve body 20 moves away from the valve seat 13, resulting in free flow, and when the fluid flows from the second port 1b to the first port 1a, the valve body 20 sits on the valve seat 13, resulting in controlled flow.

[0034] Furthermore, in the embodiment described above, the valve body 20 is provided with a tapered portion 23, and is configured so that the tapered portion 23 is in close contact with the edge of the valve seat 13 when seated. However, it is also possible to configure the valve body and the valve seat 13 to be in close contact over a surface without providing a tapered portion. In that case, a throttling can be formed by providing a groove at the tip of the valve body that allows the second flow path and the first flow path to communicate when seated, or by providing a throttling hole that penetrates the tip of the valve body.

[0035] Furthermore, while grooves and throttling holes were used as throttling points through which the controlled flow passes in the aforementioned embodiment, any throttling point such as a nozzle can be used instead. The size and shape of the throttling point can also be arbitrarily set according to the required flow rate of the controlled flow.

[0036] <Test Results> Next, the results of tests conducted using Examples 1 to 3 of the flow control valve according to the present invention and a comparative example of a conventional flow control valve for comparison will be described. The only difference between Examples 1 to 3 and the comparative example is the configuration of the throttling of the valve body of the flow control valve. Example 1 is an example of the first embodiment described above, in which the groove width is 1.3 mm, the groove depth is 1.1 mm, and the angle of the bottom of the groove is 45°. Example 2 is an example of the second embodiment described above, in which the groove width is 1.3 mm, the groove depth is 1.1 mm, the angle of the bottom of the groove is 45°, and the inclination of the groove with respect to the center line of the valve body in a side view is 15°. Example 3 is an example of the third embodiment described above, in which the diameter of the throttling hole is 1.3 mm, and the inclination of the direction in which the throttling hole extends with respect to the center line of the valve body is 30°. In contrast to these, the comparative example has a throttling hole as the throttling of the valve body, the throttling hole is arranged along the center line of the valve body, and the diameter of the throttling hole is 1.3 mm.

[0037] Hydraulic fluid was used as the fluid flowing through the flow control valve. To identify conditions where abnormal noise is likely to occur under controlled flow in the flow control valve, tests were conducted with the pressure at the second port (primary pressure) set to 5 MPa, 10 MPa, 15 MPa, and 20 MPa, and the pressure at the first port (secondary pressure) set to 1 MPa, and the presence or absence of abnormal noise was checked. The results are shown in Table 1.

[0038] [Table 1]

[0039] As shown in Table 1, in the comparative examples of conventional flow control valves, no abnormal noise occurred when the pressure at the second port was 5 MPa, but abnormal noise occurred at all pressures of 10 MPa, 15 MPa, and 20 MPa. In contrast, in Examples 1 to 3 of the flow control valve according to the present invention, no abnormal noise occurred at all pressures of 5 MPa, 10 MPa, 15 MPa, and 20 MPa at the second port. [Explanation of symbols]

[0040] 1. Flow control valve 1a First port 1b Second port 10 valve boxes 11. First channel (channel) 11a Wall surface 12 Second channel (channel) 13 valve seats 14 Spring retaining part 20 valve body 20a Small diameter section 20b Large diameter section 20c tip 21 Connecting channel 22 Communication hole 23 Tapered section 24 grooves (restrictions) 24a bottom 25 grooves (restrictions) 26 Aperture holes (aperture) 30 springs

Claims

[Claim 1] A flow control valve having a first port and a second port, wherein the flow from the first port to the second port is free flow and the flow from the second port to the first port is controlled flow, A flow path connecting the first port and the second port, A valve body housed within the flow path so as to be movable along the flow path, The flow path includes a valve seat on which the valve body sits when the fluid flows from the second port to the first port, When the valve body is seated on the valve seat, a throttling mechanism is provided on the valve body that connects to the flow path. When the fluid flows from the second port to the first port, the fluid flowing out of the throttle hits the wall of the flow path. The valve body is provided with a groove, and when the valve body is seated on the valve seat, the groove constitutes the throttle. Only one groove is provided on the valve body. A flow control valve characterized by the following features.

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