Fluid Control Valve

Abstract

The purpose of the present invention is to provide a fluid control valve which exhibits extremely high responsiveness not only when the pressure of a working fluid which has flown into a first flow path is high but also when the pressure of the working fluid in the first flow pat is low.　A fluid control valve V is provided with a valve seat 45a, a valve body 61 that is brought into contact with and is separated from the valve seat 45a, a first biasing means 64 for biasing the valve body 61 in a valve closing direction, and a second biasing means 65 having a spring force smaller than that of the first biasing means 64. The fluid control valve V can discharge a working fluid through a second flow path 13 in accordance with the pressure of the working fluid in a first flow path 11. In the valve body 61, a base 62 biased by the first biasing means 64 and an opening / closing part 63 that is brought into contact with and is separated from the valve seat 45a are arranged so as to be divided in an axial direction. The second biasing means 65 is disposed so as to be able to separate the base 62 and the opening / closing part 63 from each other in the axial direction.

Description

[Technical field]

[0001] The present invention relates to a valve for controlling a working fluid, for example, a fluid control valve having a relief function capable of releasing a working fluid. [Background technology]

[0002] Valves used to control working fluids in various industrial fields have a valve body that moves in and out of contact with a valve seat, and the flow rate and pressure of the working fluid can be controlled by adjusting the valve opening. Such fluid control valves are broadly classified into valves that detect the fluid pressure on the secondary side and adjust the valve opening to throttle the amount of fluid introduced from the primary side to control the flow rate and pressure of the working fluid on the primary side (e.g., pressure reducing valves, etc.), and valves that detect the fluid pressure of the working fluid and release the working fluid to the outside when the fluid pressure exceeds a certain level, thereby controlling the flow rate and pressure of the working fluid, i.e., valves with a so-called relief function. Depending on the equipment in which they are used, a fluid control valve with a relief function may be required to have an extremely high response relief function.

[0003] Equipment in which a fluid control valve with a highly responsive relief function is used includes shock absorbers, and in order to control the damping force, a fluid control valve having a relief function in which a valve body moves away from a valve seat in response to the fluid pressure in the piston chamber is fluidly connected to a piston chamber in which a piston in the shock absorber is located and a reservoir chamber that is provided so as to be able to communicate with the piston chamber.

[0004] An example of a fluid control valve with a relief function used in a shock absorber is disclosed in Patent Document 1, in which the fluid control valve includes a valve housing having a first flow path communicating with a piston chamber of the shock absorber and a second flow path communicating with a reservoir chamber, a valve body and a valve seat provided between the first and second flow paths, a first biasing means for biasing the valve body in a valve closing direction, and a second biasing means having a spring force lower than that of the first biasing means, the first biasing means and the second biasing means being arranged in series. The first biasing means and the second biasing means press the valve body against the valve seat, making it possible to maintain the valve closed state.

[0005] This fluid control valve is capable of simultaneously compressing the second biasing means and the first biasing means to discharge the working fluid when the pressure of the working fluid flowing into the first flow path is high, and preferentially compressing the second biasing means when the pressure of the working fluid in the first flow path is low. In other words, when the pressure of the working fluid in the first flow path is equal to or higher than low and lower than high, it is possible to discharge the working fluid without requiring any movement against the biasing force of the first biasing means. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2011-501798 A (pages 6 and 7, Figure 2) Summary of the Invention [Problem to be solved by the invention]

[0007] Thus, in a fluid control valve such as that of Patent Document 1, when the pressure of the working fluid in the first flow path is low, it is possible to release the working fluid without the need for movement against the biasing force of the first biasing means; however, due to the mass of the moving valve body and furthermore the fluid resistance, etc., it does not achieve a satisfactory relief function from the standpoint of responsiveness.

[0008] The present invention has been made in consideration of such problems, and has an object to provide a fluid control valve which has a high response when the pressure of the working fluid flowing into the first flow path is high, as well as an extremely high response when the pressure of the working fluid in the first flow path is low. [Means for solving the problem]

[0009] In order to solve the above problems, the fluid control valve of the present invention comprises: A valve seat; A valve body that moves in and out of contact with the valve seat; A fluid control valve including a first biasing means for biasing the valve body in a valve closing direction and a second biasing means having a spring force lower than that of the first biasing means, and capable of discharging a working fluid into a second flow path in response to a pressure of the working fluid in a first flow path, The valve body is arranged so that a base portion that is biased by the first biasing means and an opening / closing portion that moves toward and away from the valve seat are divided in the axial direction, and the second biasing means is arranged so as to be able to separate the base portion and the opening / closing portion in the axial direction. According to this, when the pressure of the working fluid in the first flow path increases, the opening / closing part moves against the second biasing means, which has a lower spring force, in priority to the base and the first biasing means. Therefore, when the pressure of the working fluid in the first flow path is low, the opening / closing part can move without moving the base or the first biasing means, and a highly responsive fluid control valve can be provided. Also, when the pressure of the working fluid in the first flow path is high, the base is further pressed by the second biasing means and the opening / closing part from a state in which the opening / closing part moves against the second biasing means, and the base, the second biasing means and the opening / closing part move against the first biasing means, and a highly responsive fluid control valve can be provided.

[0010] The base may be axially slidable relative to the valve housing in which the base is disposed. According to this, the base is guided by the valve housing, so that the operation of the valve body can be stabilized.

[0011] The opening / closing portion may be axially slidable relative to the base portion. According to this, the opening / closing portion moves while being guided coaxially relative to the base, so that the valve opening degree can be controlled with high precision.

[0012] A space within a valve housing in which the base portion and the first biasing means are accommodated may be defined as a pilot control chamber, and the opening / closing portion may have a communication passage that communicates between the first flow path and the pilot control chamber. This makes it possible to change the pressure of the working fluid in the pilot control chamber by changing the flow rate of the working fluid flowing through the pilot control chamber, and accordingly, the fluid control characteristics can be changed while maintaining high responsiveness.

[0013] The second biasing means may be disposed between the base and the opening / closing portion and outside the pilot control chamber. According to this, since the second biasing means is not exposed to the pilot control chamber through which the working fluid passes, it is possible to prevent deterioration of the second biasing means and the inclusion of contaminants in the second biasing means. [Brief description of the drawings]

[0014] [Figure 1] 1 is a cross-sectional view showing a fluid control valve according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view showing a state in which a pilot valve is opened in the fluid control valve of the first embodiment. [Diagram 3] FIG. 3 is a cross-sectional view showing a state in which a pilot valve is closed in the fluid control valve of the first embodiment. [Figure 4] 2 is an enlarged cross-sectional view showing a main valve in the fluid control valve of the first embodiment. FIG. [Diagram 5] FIG. 4 is a plan view showing a second biasing means constituting the main valve. [Figure 6] 3A to 3C are cross-sectional views showing, side by side, a state in which the main valve is closed in the fluid control valve of the first embodiment and a state in which the second biasing means is compressed and opened. [Figure 7]3A to 3C are cross-sectional views showing, side by side, a state in which the main valve is closed in the fluid control valve of the first embodiment and a state in which the first and second biasing means are compressed and released. [Figure 8] FIG. 5 is a cross-sectional view showing a main part of a fluid control valve according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A fluid control valve according to an embodiment of the present invention will be described below with reference to the accompanying drawings. EXAMPLES

[0016] A fluid control valve according to a first embodiment will be described with reference to Figs. 1 to 7. Although the first embodiment will be described using a fluid control valve used in a shock absorber as an example, the fluid control valve can also be used for other purposes. In the following description, the top and bottom of the fluid control valve as viewed from the front of Fig. 1 will be referred to as the top and bottom of the fluid control valve. In more detail, the bottom side of the paper on which the main valve 60 is disposed will be referred to as the bottom side of the fluid control valve, and the top side of the paper on which the solenoid 80 as a drive source is disposed will be referred to as the top side of the fluid control valve.

[0017] 1, a fluid control valve V of the present invention is fluidly connected to an absorber piston chamber P and a reservoir chamber R of a shock absorber A.

[0018] When the absorber piston moves axially and the pressure of the working fluid in the first flow path 11 increases, the main valve 60 of the fluid control valve V opens and causes the working fluid to flow from the second flow path 13 to the reservoir chamber R. In this way, the fluid control valve V controls the flow rate of the working fluid flowing from the absorber piston chamber P toward the reservoir chamber R.

[0019] In the flow control valve V, the flow control characteristic of the main valve 60 is adjusted by the pilot valve 50.

[0020] As a result, the fluid control valve V controls the damping force in the shock absorber A.

[0021] Next, there will be described the structure of the fluid control valve V. As shown in FIG.

[0022] Of these, the pilot valve 50 is disposed at the upper end portion within the valve housing 10. Furthermore, the main valve 60 is disposed below the pilot valve 50 within the valve housing 10.

[0023] The pilot valve 50 is composed of a pilot valve body 51 and a pilot valve seat 40a. The pilot valve 50 opens and closes when a sealing body 54 constituting the pilot valve body 51 comes into contact with and separates from the pilot valve seat 40a.

[0024] The main valve 60 is configured to be opened and closed by an opening / closing portion 63 constituting the main valve body 61 coming into contact with and separating from the main valve seat 45a.

[0025] First, a description will be given of the solenoid 80. The solenoid 80 is connected to the valve housing 10 and applies a driving force to the pilot valve element 51.

[0026] As shown in FIG. 1, the solenoid 80 is mainly composed of a casing 81, a center post 82, a rod 83, a movable core 84, a coil spring 85, a coil 86, a sleeve 87, and bearings 88 and 89.

[0027] The casing 81 has a stepped cylindrical main body 81a into which a center post 82 is inserted and fixed from below in the axial direction.

[0028] The casing 81 is also formed with an opening 81b that is continuous with the lower end of the main body 81a and is open downward.

[0029] The center post 82 is formed in a stepped cylindrical shape from a rigid body made of a magnetic material such as iron or silicon steel.

[0030] The center post 82 has a cylindrical main body portion 82a extending in the axial direction.

[0031] Furthermore, the center post 82 has an opening 82b that is continuous with the lower end of the main body 82a and that is open downward.

[0032] The rod 83 is formed in a cylindrical shape. The rod 83 is inserted through the center post 82 and is arranged so as to be capable of reciprocating in the axial direction.

[0033] Furthermore, the rod 83 is inserted into and fixed to the movable core 84. As a result, when the solenoid 80 is energized, the rod 83 is moved by the movable core 84 which moves in the valve closing direction. Accordingly, the rod 83 moves the pilot valve element 51 in the valve closing direction, i.e., downward in the axial direction.

[0034] Additionally, the upper end of rod 83 is inserted into bearing 88, and the lower end is inserted into bearing 89. The movement of rod 83 in the axial direction is guided by these bearings 88 and 89. Therefore, rod 83 is less likely to tilt in the radial direction during the movement in the axial direction.

[0035] Further, the rod 83 is formed with a communication passage 83a penetrating therethrough in the axial direction.

[0036] A communication groove 88a extending in the axial direction is formed in the bearing 88. This reduces the influence of the working fluid when the rod 83 and the movable core 84 move.

[0037] The coil spring 85 is disposed between the pilot valve seat member 40 and the pilot valve body 51 .

[0038] The coil spring 85 biases the pilot valve element 51 in the valve opening direction of the pilot valve 50, that is, in the axially upward direction.

[0039] The coil 86 is an excitation coil wound around the outside of the center post 82 via a bobbin.

[0040] The sleeve 87 is formed in a cylindrical shape with a bottom. Bearings 88 and 89 that guide the movement of the rod 83 are fitted and fixed in the sleeve 87.

[0041] Next, a description will be given of the configuration on the valve housing 10 side. The elements on the valve housing 10 side are the valve housing 10, a pilot valve 50, and a main valve 60.

[0042] As shown in FIG. 1, a valve housing 10 is made of a metal or resin material and has a cylindrical shape with an inner step.

[0043] The valve housing 10 is formed with, in order from the top in the axial direction, a cylindrical portion 10a, a small-diameter cylindrical portion 10b with a bottom, a medium-diameter cylindrical portion 10c with a bottom, and a large-diameter cylindrical portion 10d with a bottom.

[0044] A pilot valve body 51 is inserted into the cylindrical portion 10a from above in the axial direction.

[0045] 2, the pilot valve element 51 is formed in a T-shape in cross section. In detail, the pilot valve element 51 is composed of a cylindrical portion 52, a flange portion 53, and a sealing body 54.

[0046] A recess 52a recessed axially downward is formed at the upper end of the cylindrical portion 52. The lower end of the rod 83 abuts against the bottom surface of the recess 52a. As a result, the pilot valve body 51, which receives the biasing force of the coil spring 85, is pressed against the rod 83.

[0047] A communication passage 52b is formed on the inner diameter side of the recess 52a, penetrating in the axial direction.

[0048] The cylindrical portion 52 is formed in a stepped cylindrical shape extending in the axial direction. More specifically, the cylindrical portion 52 is formed with a large diameter portion 52c, a medium diameter portion 52d, and a small diameter portion 52e in this order from the top in the axial direction.

[0049] An upper end of the large diameter portion 52c is continuous with a flange portion 53 extending in the outer diameter direction. A lower end of the large diameter portion 52c is continuous with a medium diameter portion 52d having a diameter smaller than that of the large diameter portion 52c.

[0050] The flange portion 53 is disk-shaped and extends radially outward from the upper end of the cylindrical portion 52 .

[0051] The flange portion 53 has a lower end formed with an annular recess 53a that is recessed axially upward.

[0052] The annular recess 53a is formed so that its outer diameter is substantially the same as the outer diameter of an annular recess 41 of the pilot valve seat member 40, which will be described later.

[0053] A coil spring 85 is disposed in the annular recess 53a and the annular recess 41 of the pilot valve seat member 40. Therefore, when the coil spring 85 is compressed in the axial direction, it is guided by the outer circumferential surfaces of the annular recess 53a and the annular recess 41 of the pilot valve seat member 40, preventing the coil spring 85 from twisting or bending.

[0054] A communication passage 53b penetrating in the axial direction is formed in the flange portion 53. The communication passage 53b communicates between the cylindrical portion 10a of the valve housing 10 and an opening 82b of the center post 82 (see FIG. 1).

[0055] In addition, the outer peripheral surface of the flange portion 53 is formed to be movable while being in sliding contact with the inner peripheral surface of the cylindrical portion 10a of the valve housing 10. This enables the cylindrical portion 10a to guide the movement of the pilot valve element 51.

[0056] A small diameter portion 52e having a diameter smaller than that of the medium diameter portion 52d is continuous with the lower end of the medium diameter portion 52d.

[0057] An annular groove 52f is formed in the small diameter portion 52e, which is continuous with the lower end surface of the medium diameter portion 52d and recessed toward the inner diameter side. An inner diameter side end of a disk-shaped sealing body 54 is inserted and fixed in the annular groove 52f. That is, the sealing body 54 is cantilevered by the annular groove 52f and protrudes in the outer diameter direction from the annular groove 52f.

[0058] The sealing body 54 is made of a metal material and is elastically deformable by bending in the axial direction (see FIG. 3). Needless to say, the material forming the sealing body 54 is not limited to metal.

[0059] The sealing body 54 is adapted to be seated on or removed from the pilot valve seat 40a.

[0060] Returning to the configuration of the valve housing 10, the small-diameter, bottomed cylindrical portion 10b is continuous with the cylindrical portion 10a, and has a larger diameter on the inside than the cylindrical portion 10a, and is recessed axially upward.

[0061] A pilot valve seat member 40 is press-fitted from below in the axial direction into the small-diameter, bottomed cylindrical portion 10b and fixed integrally thereto in a substantially sealed state.

[0062] 2, the pilot valve seat member 40 is formed in a circular plate shape from a metal material or a resin material. An annular recess 41 is formed at the upper end of the pilot valve seat member 40 and recessed axially downward.

[0063] Further, an annular protrusion 42 is formed at the upper end of the pilot valve seat member 40, protruding axially upward on the inner diameter side of the annular recess 41. The upper end of the annular protrusion 42 is the pilot valve seat 40a.

[0064] Further, a circular recess 43 is formed at the upper end of the pilot valve seat member 40, on the inner diameter side of the annular protrusion 42, so as to be recessed axially downward from the bottom surface of the annular recess 41. Further, a communication passage 44 is formed at the bottom of the circular recess 43, penetrating therethrough in the axial direction.

[0065] Returning to the configuration of the valve housing 10, the medium-diameter bottomed cylindrical portion 10c is continuous with the small-diameter bottomed cylindrical portion 10b, and has a larger diameter on the inside than the small-diameter bottomed cylindrical portion 10b, and is recessed axially upward.

[0066] The main valve body 61 and the coil spring 64 are inserted into the medium-diameter, bottomed cylindrical portion 10c from the axially downward side. In addition, the upper end of the main valve seat member 45, which is press-fitted into the medium-diameter, bottomed cylindrical portion 10c from the axially downward side, is fixed integrally in a substantially sealed state to the medium-diameter, bottomed cylindrical portion 10c.

[0067] 1, a pilot control chamber S is formed in the space within the small-diameter bottomed cylindrical portion 10b and the medium-diameter bottomed cylindrical portion 10c in the valve housing 10. The pilot control chamber S is defined by the small-diameter bottomed cylindrical portion 10b, the medium-diameter bottomed cylindrical portion 10c, the pilot valve seat member 40, the pilot valve element 51, and the main valve element 61.

[0068] That is, the pilot control chamber S includes the circular recess 43 of the pilot valve seat member 40 and the communication passage 44, and is a flow passage upstream of the pilot valve body 51, that is, an upstream flow passage of the pilot valve 50 (see FIG. 2).

[0069] 4, the main valve body 61 is mainly composed of a piston 62 serving as a base formed in a cylindrical shape having a U-shape in cross section, and an opening / closing part 63. That is, the main valve body 61 is divided into two parts in the axial direction by the piston 62 and the opening / closing part 63.

[0070] The piston 62 has a cylindrical portion 62a extending in the axial direction and a bottom portion 62b extending radially inward from the lower end of the cylindrical portion 62a, and a through hole 62c penetrating in the axial direction is formed in the center of the bottom portion 62b.

[0071] A coil spring 64 is disposed in a compressed state between a bottom 62b of the piston 62 and the pilot valve seat member 40, as a first biasing means for biasing the piston 62 in the valve closing direction, i.e., axially downward. A leaf spring 65 is disposed between the piston 62 and the opening / closing portion 63, as a second biasing means for biasing the opening / closing portion 63 in the valve closing direction, i.e., axially downward.

[0072] The piston 62 also has a recess 61a that is defined by the inner circumferential surface of the cylindrical portion 62a and the upper end surface of the bottom portion 62b and is recessed axially downward in a funnel shape.

[0073] An annular recess 62d recessed axially upward is formed at the lower end of the cylindrical portion 62a on the outer diameter side.

[0074] The opening / closing portion 63 has an annular outer diameter side protrusion 63a protruding axially upward from the outer diameter side end portion, and an annular inner diameter side protrusion 63b protruding axially upward from the radial center portion, and an annular recess 63c is formed between the outer diameter side protrusion 63a and the inner diameter side protrusion 63b. The inner diameter side protrusion 63b is inserted into a through hole 62c of the piston 62.

[0075] When the inner diameter side protrusion 63b of the opening / closing part 63 is inserted into the through hole 62c of the piston 62, the outer circumferential surface of the inner diameter side protrusion 63b and the inner surface of the bottom part 62b of the piston 62 are formed to be approximately parallel to each other. Therefore, the opening / closing part 63 is movable in the axial direction while being in sliding contact with the piston 62.

[0076] A communication passage 63d penetrating in the axial direction is formed in the radial center of the opening / closing portion 63. The inside of the main valve body 61 communicates with the first flow passage 11 through the communication passage 63d of the opening / closing portion 63.

[0077] An annular recess 63e is formed in an outer diameter side lower end of the opening / closing part 63. A lower end 63f of the opening / closing part 63 located on the outer diameter side of the annular recess 63e is seated on the main valve seat 45a when the main valve 60 is in a closed state.

[0078] 4 and 5, the leaf spring 65 has a stepped circular and plate-like cross section and has a lower spring constant than the coil spring 64. The leaf spring 65 is mainly composed of an annular inner diameter plate portion 65a, a plurality of connecting portions 65b that are bent upward from the outer diameter end of the inner diameter plate portion 65a and bridge the inner diameter end portion 65a, and an annular outer diameter plate portion 65c that is bent downward from the outer diameter end of the connecting portions 65b and connects the connecting portions 65b.

[0079] In the leaf spring 65, the inner diameter plate portion 65a and the outer diameter plate portion 65c are substantially parallel to each other. As a result, when the leaf spring 65 receives an axial load, the leaf spring 65 is deformable so that the bending angle of the connecting portion 65b becomes smaller, that is, so that the axial distance between the inner diameter plate portion 65a and the outer diameter plate portion 65c becomes smaller.

[0080] When the main valve 60 is in the closed state, the leaf spring 65 is disposed such that the upper end surface of the inner diameter plate portion 65a abuts against the lower end surface of the bottom portion 62b of the piston 62, and the lower end surface of the outer diameter plate portion 65c abuts against the upper end surface of the outer diameter side protrusion 63a of the opening / closing portion 63. When the main valve 60 is in the closed state, the spring force of the leaf spring 65 is smaller than the spring force of the coil spring 64.

[0081] Returning to the configuration of the valve housing 10, the large-diameter, bottomed cylindrical section 10d is continuous with the medium-diameter, bottomed cylindrical section 10c, and has a larger diameter on the inside than the medium-diameter, bottomed cylindrical section 10c, and is recessed axially upward.

[0082] A main valve seat member 45 is press-fitted from below in the axial direction into the large-diameter, bottomed cylindrical portion 10d and fixed integrally thereto in a substantially sealed state.

[0083] As shown in FIG. 4, the main valve seat member 45 is made of a metal material or a resin material and is formed in a cylindrical shape having a first flow passage 11 passing therethrough in the axial direction.

[0084] The main valve seat member 45 includes a cylindrical portion 46 extending in the axial direction, and an annular flange portion 47 extending radially outward from the lower end of the cylindrical portion 46. In addition, with the upper end of the cylindrical portion 46 of the main valve seat member 45 inserted into the lower end of the medium-diameter, bottomed cylindrical portion 10c, the flange portion 47 is press-fitted and fixed from below in the axial direction into the large-diameter, bottomed cylindrical portion 10d via a gasket in a sealed state.

[0085] Further, an annular recess 48 that is recessed axially downward and U-shaped in cross section is formed at the upper end of the cylindrical portion 46. A communication passage 45b is formed on the inner diameter side of the annular recess 48, penetrating in the axial direction and into which the working fluid flows from the absorber piston chamber P.

[0086] Furthermore, an annular land 49 is formed between the annular recess 48 and the communication passage 45b on the inner diameter side of the cylindrical portion 46. A plurality of communication grooves 49a are formed in the circumferential direction at the upper end of the land 49, extending radially and communicating between the annular recess 48 and the communication passage 45b. These communication grooves 49a allow the working fluid to be introduced into the annular recess 48 and the annular recess 63e of the opening / closing portion 63 even when the main valve 60 is in a closed state.

[0087] The communication passage 45 b of the main valve seat member 45 , the annular recess 48 and the communication groove 49 a , together with the lower end of the opening / closing portion 63 , constitute a flow passage on the upstream side of the main valve 60 , that is, the first flow passage 11 .

[0088] 1, a communicating groove 10e that is L-shaped and faces downward in cross section is formed on the outer surface of the valve housing 10, extending from the upper end of the cylindrical portion 10a to the side surface. In detail, the communicating groove 10e extends in the outer radial direction along the upper end surface of the valve housing 10, and then extends axially downward, approximately perpendicular to the outer circumferential surface of the valve housing 10.

[0089] In addition, when the valve housing 10 is inserted into the opening 81b of the casing 81, the lower end of the communicating groove 10e extends downward further than the lower end of the opening 81b, allowing the working fluid to flow into the reservoir chamber R from the lower end of the communicating groove 10e.

[0090] As a result, the communication groove 10 e constitutes the pilot downstream flow passage 12 of the pilot valve 50 .

[0091] More specifically, the pilot downstream flow path 12 is composed of a cylindrical portion 10a in the valve housing 10, a small-diameter, bottomed cylindrical portion 10b, a communicating groove 10e, an upper end portion of the pilot valve seat member 40 on the outer diameter side of the annular protrusion 42, an opening 81b in the casing 81, and an opening 82b in the center post 82.

[0092] As shown in FIG. 4, the valve housing 10 is provided with a communication passage 10f that extends from the medium-diameter, bottomed cylindrical portion 10c toward the outer diameter side and connects the inside of the medium-diameter, bottomed cylindrical portion 10c to the reservoir chamber R, allowing the working fluid to flow into the reservoir chamber R from the communication passage 10f.

[0093] As a result, the communication passage 10 f constitutes a flow passage downstream of the main valve 60 , that is, the second flow passage 13 .

[0094] More specifically, the second flow passage 13 is constituted by the medium-diameter bottomed cylindrical portion 10c, the large-diameter bottomed cylindrical portion 10d, the communication passage 10f, the main valve body 61, and the main valve seat member 45 in the valve housing 10.

[0095] Next, the operation of the fluid control valve V, mainly the opening and closing operations of the pilot valve 50 and the main valve 60, will be described with reference to FIGS.

[0096] First, the fluid control valve V in the de-energized state will be described. With reference to Figures 1 and 2, in the de-energized state, the pilot valve body 51 of the pilot valve 50 is pressed axially upward by the biasing force of the coil spring 85. As a result, the sealing body 54 (see Figure 2) of the pilot valve body 51 is separated from the pilot valve seat 40a, and the pilot valve 50 is opened. The pilot valve opening degree at this time is maximum in this embodiment.

[0097] In a non-energized state, when the shock absorber A operates and the pressure of the working fluid in the first flow path 11 increases, the working fluid passes through the communication path 63d (see FIG. 4) of the opening / closing portion 63 and the pilot control chamber S, and flows from the pilot downstream flow path 12 into the reservoir chamber R. At the same time, depending on the pressure of the working fluid, as described below, the working fluid may also flow from the second flow path 13 into the reservoir chamber R.

[0098] The fluid control valve V is formed such that the cross-sectional area of the flow path in the communication path 63d of the opening / closing portion 63 is narrow. Therefore, even when the pressure of the working fluid in the first flow path 11 increases, the pressure of the working fluid in the pilot control chamber S is less likely to increase immediately in response to the pressure of the working fluid in the first flow path 11. Therefore, a differential pressure is generated between the pressure of the working fluid in the first flow path 11 and the pressure of the working fluid in the pilot control chamber S. The larger this differential pressure becomes, the easier it is for the main valve 60 to open.

[0099] Based on this, in this embodiment, the pressure of the working fluid in the first flow path 11 sufficient to deform only the leaf spring 65 with respect to the pressure of the working fluid in the pilot control chamber S is defined as pressure P1, and the pressure of the working fluid in the first flow path 11 sufficient to deform the leaf spring 65 and the coil spring 64 is defined as pressure P2. Here, pressure P1 is lower than pressure P2 (P1 < P2). In the following description, the pressure of the working fluid in the first flow path 11 is referred to as "pressure Pin in the first flow path 11", and the pressure of the working fluid in the pilot control chamber S is referred to as "pressure Ps in the pilot control chamber S".

[0100] After the main valve 60 is opened, when the differential pressure ΔP (= Pin - Ps) between the pressure Pin in the first flow path 11 and the pressure Ps in the pilot control chamber S becomes small, the main valve 60 closes.

[0101] The factors that cause the differential pressure ΔP to decrease include the working fluid flowing from the second flow path 13 into the reservoir chamber R through the main valve 60, resulting in a decrease in the pressure Pin in the first flow path 11; the working fluid flowing from the communication passage 63d into the pilot control chamber S, causing a decrease in the pressure Pin in the first flow path 11; the volume of the pilot control chamber S decreasing due to the movement of the main valve body 61, leading to an increase in the pressure Ps in the pilot control chamber S, etc. Hereinafter, the opening and closing operation of the main valve 60 will be described in more detail with specific examples.

[0102] Referring to FIGS. 1 and 6, for example, when driving on a smooth road surface, the absorber piston in the shock absorber A reciprocates with a minute stroke. When the pressure Pin in the first flow path 11 is less than the pressure P1 (Pin < P1), due to the biasing forces of the coil spring 64 and the leaf spring 65, the lower end 63f of the opening and closing portion 63 of the main valve body 61 seats on the main valve seat 45a, and the main valve 60 is closed.

[0103] Referring to the left half of FIG. 6, in the closed state of the main valve 60, the force with which the coil spring 64 biases the piston 62 downward is greater than the force with which the leaf spring 65 biases the piston 62 upward. As a result, the inner diameter plate portion 65a on the inner diameter side of the leaf spring 65 is pushed axially downward by the coil spring 64, and the outer diameter plate portion 65c on the outer diameter side is in contact with and supported from below by the outer diameter side convex portion 63a of the opening and closing portion 63, and is bent and deformed in the compression direction. At this time, the bottom surface of the annular recess 63c of the inner diameter plate portion 65a of the leaf spring 65 and the opening and closing portion 63, and the bottom surface of the recess 62d of the outer diameter plate portion 65c of the leaf spring 65 and the piston 62 are axially separated from each other, serving as the axial movement allowance of the opening and closing portion 63.

[0104] Referring to FIGS. 1 and 6, for example, when driving on a rough road surface, the absorber piston in the shock absorber A reciprocates with a small stroke and repeatedly moves back and forth. When the pressure Pin in the first flow path 11 is greater than or equal to the pressure P1 and less than the pressure P2 (P2 > Pin ≥ P1), only the opening and closing portion 63 moves axially upward against the biasing force of the leaf spring 65.

[0105] That is, the lower end 63f of the opening / closing part 63 is slightly separated from the main valve seat 45a, opening the main valve 60. This causes the working fluid to flow from the second flow path 13 through the main valve 60 into the reservoir chamber R (see the right half of FIG. 6).

[0106] At this time, as only the opening / closing portion 63 moves, the excess working fluid in the pilot control chamber S flows into the reservoir chamber R from the pilot downstream flow passage 12.

[0107] As described above, since the main valve 60 closes as the differential pressure ΔP decreases, the valve opening degree of the main valve 60 increases as the pressure Pin in the first flow path 11 approaches the pressure P2.

[0108] Furthermore, when the opening / closing part 63 moves against the biasing force of the leaf spring 65, the lower end surface of the inner diameter plate part 65a of the leaf spring 65 is pressed against the bottom surface of the annular recess 63c, and the upper end surface of the outer diameter plate part 65c of the leaf spring 65 approaches or abuts against the bottom surface of the recess 62d of the piston 62. As a result, when the pressure Pin of the working fluid in the first flow path 11 is pressure P2, the upper end surface of the outer diameter plate part 65c of the leaf spring 65 abuts against the bottom surface of the recess 62d of the piston 62, so that the pressure acting from the working fluid in the first flow path 11 is easily applied to the piston 62 via the opening / closing part 63.

[0109] 1 and 7, when the pressure Pin in the first flow path 11 is equal to or greater than the pressure P2 (Pin≧P2), for example, when the absorber piston in the shock absorber A is about to make a large stroke to overcome a bump in the road surface, not only the opening / closing portion 63 but also the piston 62 moves axially upward against the biasing forces of the coil spring 64 and the leaf spring 65.

[0110] That is, the lower end 63f of the opening / closing portion 63 is further separated from the main valve seat 45a, and the main valve 60 is opened. As a result, the working fluid flows from the second flow path 13 through the main valve 60 into the reservoir chamber R.

[0111] Also, when the pressure Pin in the first flow path 11 is equal to or higher than the pressure P2 (Pin ≧ P2), the valve opening degree of the main valve 60 is maximized in this embodiment (see the right half of FIG. 7).

[0112] Further, as the opening / closing part 63 moves, the surplus working fluid in the pilot control chamber S flows from the pilot downstream flow path 12 into the reservoir chamber R.

[0113] In this way, the fluid control valve V can release the working fluid to the reservoir chamber R side by opening the main valve 60 in approximately two stages in response to an increase in the pressure Pin in the first flow path 11.

[0114] Also, if the pilot valve opening degree of the pilot valve 50 is maximum in the non-energized state, the main valve 60 has a valve characteristic that makes it easy to open, so the damping force in the shock absorber A is controlled to be minimum.

[0115] Thereafter, the working fluid flows into the reservoir chamber R from the second flow path 13 through the main valve 60. As the pressure Pin in the first flow path 11 decreases, the coil spring 64 extends and the valve opening degree decreases. As described above, when the pressure Pin in the first flow path 11 is equal to or higher than the pressure P1 and lower than the pressure P2 (P2 > Pin ≧ P1), only the opening / closing part 63 moves upward in the axial direction against the biasing force of the leaf spring 65 (see the right half of FIG. 6).

[0116] Furthermore, the working fluid flows into the reservoir chamber R from the second flow path 13 through the main valve 60. When the pressure Pin in the first flow path 11 becomes lower than the pressure P1 (Pin < P1), the leaf spring 65 extends and the lower end portion 63f of the opening / closing part 63 seats on the main valve seat 45a, and the main valve 60 is closed.

[0117] Next, regarding the fluid control valve V in the energized state, the control of the damping force mainly by the pilot valve 50 will be described. Note that since the main valve 60 operates in substantially the same manner as in the non-energized state even in the energized state, the description thereof will be omitted.

[0118] Referring to Figures 1 and 3, when an electric current is applied to the solenoid 80 in an energized state (i.e., during so-called duty control), when the electromagnetic force generated by the application of electric current to the solenoid 80 exceeds the biasing force of the coil spring 85, the movable iron core 84 is pulled toward the center post 82, i.e., axially downward.

[0119] As a result, the rod 83 fixed to the movable core 84 moves axially downward together with the pilot valve body 51. In response to this, the pilot valve 50 becomes smaller in opening, and is closed when a current equal to or greater than a predetermined value is applied.

[0120] When the pilot valve is opened to a smaller degree than in the non-energized state, the working fluid in the first flow passage 11 flows from the pilot downstream flow passage 12 into the reservoir chamber R in response to the operation of the shock absorber A, similar to the non-energized state. In addition, as described above, depending on the pressure Pin in the first flow passage 11, the working fluid also flows into the reservoir chamber R from the second flow passage 13.

[0121] The smaller the pilot valve opening is, the more difficult it becomes for the working fluid to flow from the pilot control chamber S into the pilot downstream flow passage 12. Therefore, the differential pressure ΔP between the pressure Pin in the first flow passage 11 and the pressure Ps in the pilot control chamber S becomes less likely to occur, and the main valve 60 becomes more difficult to open. In other words, the damping force in the shock absorber A can be increased.

[0122] In other words, when the pilot valve opening is at a maximum, the damping force in the shock absorber A is at a minimum. That is, the damping force is controlled to be at its smallest when the fluid control valve V is in a non-energized state.

[0123] Furthermore, even if the main valve 60 is opened, the smaller the pilot valve opening degree of the pilot valve 50, the shorter the time for which the differential pressure ΔP becomes small. That is, the smaller the pilot valve opening degree of the pilot valve 50, the shorter the time for which the main valve 60 is open.

[0124] From these, the fluid control characteristic of the main valve 60 is controlled according to the pilot valve opening degree of the pilot valve 50. In this way, the fluid control valve V can variably control the damping force of the shock absorber A.

[0125] Even when a current equal to or greater than a predetermined level is applied and the pilot valve 50 is closed, if a high pressure Pin is generated in the first flow path 11, the working fluid slightly opens the pilot valve 50. As a result, the working fluid flows from the pilot downstream flow path 12 into the reservoir chamber R, similar to the non-energized state.

[0126] In this way, when the pilot valve 50 is closed in the energized state, the fluid control valve V is in a state in which the working fluid is least likely to pass through the pilot valve 50 and the main valve 60 is least likely to be opened. Therefore, the fluid control valve V can maximize the damping force in the shock absorber A.

[0127] The value of the current passed through the coil 86 constituting the solenoid 80 is set based on input parameters such as the vehicle speed, vehicle acceleration / deceleration, steering angle, road surface conditions, and spring load.

[0128] Furthermore, the pilot valve 50 in the open state may be closed by setting a current value equal to or greater than a predetermined value. EXAMPLES

[0129] Next, a fluid control valve according to a second embodiment will be described with reference to Fig. 8. Note that a description of the same configuration as in the first embodiment will be omitted.

[0130] 8, the leaf spring 165 of the fluid control valve of the second embodiment is a stepped circular plate-like spring with a lower spring constant than the coil spring 64. The leaf spring 165 is mainly composed of an annular inner diameter plate portion 165a, a plurality of connecting portions 165b that are bent downward from the outer diameter end of the inner diameter plate portion 165a and bridge the connecting portions 165b, and an annular outer diameter plate portion 165c that is bent upward from the outer diameter end of the connecting portions 165b and connects them.

[0131] In the leaf spring 165, the inner diameter plate portion 165a and the outer diameter plate portion 165c are approximately parallel to each other. As a result, when the leaf spring 165 receives an axial load, it is deformable so that the bending angle of the connecting portion 165b increases, that is, the axial distance between the inner diameter plate portion 165a and the outer diameter plate portion 165c increases.

[0132] The outer diameter plate portion 165 c of the leaf spring 165 is disposed between the coil spring 64 and the piston 62 .

[0133] The leaf spring 165 is disposed in such a state that the lower end surface of the inner diameter plate portion 165a abuts against the upper end surface of the inner diameter side protrusion 63b of the opening / closing portion 63 and receives an axial load from the coil spring 64. The force with which the inner diameter plate portion 165a of the leaf spring 165 urges the piston 62 upward is smaller than the force with which the coil spring 64 urges the inner diameter plate portion 165a of the leaf spring 165 downward, both in the closed state (see the left half of FIG. 8) and in the open state (see the left half of FIG. 8) of the main valve 60. That is, the spring force of the leaf spring 165 is smaller than the spring force of the coil spring 64.

[0134] As a result, when the main valve 60 is in a closed state, the leaf spring 165 has the inner diameter plate portion 165a on the inner diameter side pressed axially upward by the upper end surface of the inner diameter side protrusion 63b of the opening / closing portion 63, and is bent and deformed in the expanding direction (see the left half of FIG. 8). At this time, the opening / closing portion 63 and the piston 62 are separated in the axial direction, providing a movement allowance for the opening / closing portion 63 in the axial direction.

[0135] Furthermore, when the pressure Pin in the first flow path 11 is equal to or greater than the pressure P1 and less than the pressure P2 (P2>Pin≧P1), only the opening / closing portion 63 of the main valve 60 moves axially upward against the biasing force of the leaf spring 165.

[0136] That is, the lower end portion 63f of the opening / closing portion 63 is slightly separated from the main valve seat 45a, and the main valve 60 is opened. As a result, the working fluid flows from the second flow path 13 into the reservoir chamber R through the main valve 60. At this time, the leaf spring 165 is bent and deformed in the expanding direction as the opening / closing portion 63 approaches the piston 62.

[0137] Also, referring to the right half of FIG. 8, when the opening / closing portion 63 moves against the leaf spring 165, the opening / closing portion 63 approaches or contacts the piston 62. Thus, when the pressure Pin in the first flow path 11 is large, since the opening / closing portion 63 contacts the piston 62, the pressure acting from the working fluid in the first flow path 11 easily acts on the piston 62 via the opening / closing portion 63.

[0138] Thereafter, when the pressure Pin in the first flow path 11 becomes less than the pressure P1 (Pin < P1), the leaf spring 165 extends and the lower end portion 63f of the opening / closing portion 63 seats on the main valve seat 45a, and the main valve 60 is closed.

[0139] As described above, in the fluid control valve V of the present embodiment, when the pressure Pin in the first flow path 11 increases, the opening / closing portion 63 moves against the leaf spring 65 having a lower spring force than the piston 62 and the coil spring 64 with priority. Therefore, when the pressure in the first flow path 11 is small, as shown in FIG. 6, the opening / closing portion 63 can move without accompanying the movement of the piston 62 or the coil spring 64, and a highly responsive fluid control valve V can be provided.

[0140] Also, when the pressure of the working fluid in the first flow path 11 is large, as shown in FIG. 7, the piston 62 is pressed by the leaf spring 65 and the opening / closing portion 63 from the state where the opening / closing portion 63 is moving against the leaf spring 65, and the piston 62, the leaf spring 65, and the opening / closing portion 63 move against the coil spring 64, so that a highly responsive fluid control valve V can be provided.

[0141] In addition, as shown in FIG. 4, the flow path cross-sectional area between the inner diameter side convex portion 63b of the opening / closing portion 63 and the through hole 62c of the piston 62 is narrower than the flow path cross-sectional area at the communicating groove 49a of the land 49. Therefore, when the pressure in the first flow path 11 increases, the responsiveness of the opening / closing portion 63 when it moves against the leaf spring 65 is improved.

[0142] In addition, the piston 62 is able to slide along the inner circumferential surface of the medium-diameter, bottomed cylindrical portion 10c of the valve housing 10 when moving axially, and the movement is guided, thereby stabilizing the operation of the main valve body 61.

[0143] In addition, the opening / closing portion 63 has its inner diameter side convex portion 63b capable of sliding on the inner surface of the bottom portion 62b of the piston 62, and the opening / closing portion 63 moves while being guided coaxially relative to the piston 62, so that the valve opening degree of the main valve 60 can be controlled with high precision.

[0144] In addition, the outer diameter of the opening / closing portion 63 is smaller than the inner diameter of the medium-diameter, bottomed cylindrical portion 10c of the valve housing 10, and its outer peripheral surface is spaced apart from the inner peripheral surface of the medium-diameter, bottomed cylindrical portion 10c. This improves responsiveness compared to a configuration in which the outer peripheral surface is arranged so as to be in sliding contact with the inner peripheral surface of the medium-diameter, bottomed cylindrical portion 10c.

[0145] Furthermore, because the leaf spring 65 is used as the second biasing means, the axial dimension of the main valve 60 can be made shorter than in a configuration in which, for example, a coil spring is used.

[0146] In addition, since it is possible to change the pressure in the pilot control chamber S by changing the flow rate of the working fluid flowing through the pilot control chamber S, the fluid control characteristics of the main valve 60 can be changed accordingly while maintaining high responsiveness.

[0147] In addition, the leaf spring 65 is disposed outside the pilot control chamber S through which the working fluid passes, and is not exposed to the pilot control chamber S, which prevents deterioration of the leaf spring 65 and the ingestion of contaminants by the leaf spring 65.

[0148] Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention also includes modifications and additions that do not deviate from the gist of the present invention.

[0149] For example, in the above embodiment, the main valve element is described as being divided into two parts, a piston and an opening / closing part, but the present invention is not limited to this, and the main valve element may be divided into three or more parts including the base and the opening / closing part, such as the base being divided into two or more parts. For example, the base, which is a rigid body, may be divided into two parts in the axial direction, and a third biasing means different from the spring forces of the first biasing means and the second biasing means may be interposed between the upper base and the lower base, so that the main valve can be opened in approximately three stages.

[0150] Further, the valve seat has been described as being formed on a valve seat member separate from the valve housing, but the present invention is not limited to this and may be formed integrally with the valve housing.

[0151] In addition, the base has been described as a piston that slides against the inner surface of the valve housing, but this is not limited thereto, and the base may be movable in the axial direction away from the inner surface of the valve housing, that is, the base may be configured other than a piston.

[0152] In addition, although the opening / closing portion has been described as sliding against the inner surface of the bottom of the piston, this is not limited thereto, and as long as the opening / closing portion is provided with a separate means for guiding its movement, such as sliding against the inner surface of the valve housing, it does not have to be slidably mounted on the base.

[0153] Further, the second biasing means has been described as being a leaf spring, but is not limited thereto and may be appropriately changed to a coil spring, a disc spring, or the like. [Explanation of symbols]

[0154] 10 Valve housing 11 First flow path 12 Pilot downstream flow path 13 Second flow path 40a Pilot valve seat 45a Main valve seat (valve seat) 50 Pilot valve 51 Pilot valve body 60 Main valve 61 Main valve body (valve body) 62 Piston (base) 63 Opening and closing section 63d Communication path 64 Coil spring (first biasing means) 65 Leaf spring (second biasing means) 80 Solenoid A. Shock absorber P absorber piston chamber R Reservoir chamber S Pilot Control Room V Fluid Control Valve

Claims

1. A valve seat; A valve body that moves in and out of contact with the valve seat; a first biasing means for biasing the valve body in a valve closing direction and a second biasing means having a spring force lower than that of the first biasing means, and a fluid control valve capable of discharging a working fluid into a second flow path in response to a pressure of the working fluid in a first flow path, The valve body is arranged such that a base portion biased by the first biasing means and an opening / closing portion that moves toward and away from the valve seat are divided in the axial direction, and the second biasing means is arranged to be capable of moving the base portion and the opening / closing portion away from each other in the axial direction, a valve housing having a base and a first biasing means mounted therein, the space within the valve housing being a pilot control chamber, and the opening / closing portion having a communication passage connecting the first flow path and the pilot control chamber.

2. 2. The fluid control valve according to claim 1, wherein the base is axially slidable relative to a valve housing in which the base is disposed.

3. The fluid control valve according to claim 2 , wherein the opening / closing portion is axially slidable relative to the base portion.

4. 4. The fluid control valve according to claim 1, wherein the second biasing means is disposed between the base portion and the opening / closing portion and outside the pilot control chamber.

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