Fluid control valve

Abstract

Provided is a fluid control valve that is less likely to malfunction due to contamination.　This fluid control valve V1 comprises a valve housing 10 having an inflow channel 11 and a discharge channel 12, a valve seat 45a disposed between the inflow channel 11 and the discharge channel 12, and a valve body 61 in which a guide part 62 is guided by an inner surface 14 of the valve housing 10 and a seal part 63 comes into contact with and separates from the valve seat 45a. The guide part 62 in the valve body 61 has a flat surface 65 and a tapering surface that tapers toward the seal part 63 side.

Description

【Technical Field】 【0001】 The present invention relates to a valve for controlling a working fluid, and more particularly to a fluid control valve having a relief function capable of discharging the working fluid, for example. 【Background Art】 【0002】 Valves used for controlling a working fluid in various industrial fields include a valve body that separates from and contacts a valve seat, and by adjusting the valve opening degree, it is possible to control the flow rate and pressure of the working fluid. 【0003】 Such fluid control valves are classified into a valve (for example, a pressure reducing valve, etc.) that detects the fluid pressure on the secondary side and adjusts the valve opening degree to throttle the fluid introduction amount from the primary side to control the flow rate and pressure of the working fluid on the primary side, and a valve that detects the fluid pressure of the working fluid and discharges the working fluid to the outside for a fluid pressure above a predetermined value to control the flow rate and pressure of the working fluid, that is, a valve having a so-called relief function. 【0004】 As an example of a device in which a fluid control valve having a relief function is used, a shock absorber has a fluid control valve fluidly connected and disposed in a piston chamber and a reservoir chamber in the shock absorber. A piston is disposed in the piston chamber. Thereby, the fluid control valve causes the valve body to separate from and contact the valve seat according to the fluid pressure in the piston chamber that changes according to the movement of the piston. By utilizing this, the shock absorber can control the damping force. 【0005】 Patent Document 1 is an example of a fluid control valve with a relief function used in a shock absorber. The fluid control valve shown therein comprises a valve housing, a valve body, a valve seat, and a biasing means. The valve housing has an inlet passage that communicates with the piston chamber of the shock absorber and a discharge passage that communicates with the reservoir chamber. That is, in the fluid control valve, the valve body and valve seat are provided between the inlet passage and the discharge passage. The valve body is biased in the closing direction by the biasing force of the biasing means and is able to maintain a closed state. When high-pressure working fluid flows into the inlet passage, the valve body separates from the valve seat against the biasing force of the biasing means in the fluid control valve. As a result, the fluid control valve discharges the working fluid from the discharge passage. [Prior art documents] [Patent Documents] 【0006】 [Patent Document 1] Japanese Patent Publication No. 2011-501798 (pages 6, 7, Figure 2) [Overview of the Initiative] [Problems that the invention aims to solve] 【0007】 In fluid control valves like the one described in Patent Document 1, the guide portion of the valve body contacts the inner circumferential surface of the valve housing, causing the valve body to move guided by the valve housing. However, in fluid control valves, contaminants can sometimes get trapped between the inner circumferential surface of the valve housing and the guide portion of the valve body. This creates resistance to the movement of the valve body, which could reduce the relief performance of the fluid control valve. 【0008】 This invention was made in view of these problems, and aims to provide a fluid control valve that is less prone to malfunctions caused by contamination. [Means for solving the problem] 【0009】 To solve the above problems, the fluid control valve of the present invention is A fluid control valve comprising: a valve housing having an inlet passage and an outlet passage; a valve seat disposed between the inlet passage and the outlet passage; and a valve body having a guide portion guided on the inner surface of the valve housing and a sealing portion that moves away from the valve seat, The guide portion of the valve body has a flat surface and a tapered surface that narrows toward the sealing portion. According to this design, the guide portion has a tapered surface that narrows from the flat surface, and since there is space on the outer diameter side of the tapered surface, the valve body can tilt significantly. As a result, contaminants that have flowed between the flat surface of the guide portion of the valve body and the inner surface of the valve housing can be easily discharged. 【0010】 The outer dimensions of the valve body may be larger at the tapered surface portion than at the sealing portion portion. According to this design, the valve body can be tilted significantly, and the sealing portion is less likely to come into contact with and damage the inner surface of the valve housing. 【0011】 The tapered surface may also be an inclined surface. According to this, since the cross-section is a straight or curved inclined surface that extends continuously, the valve body can move smoothly relative to the valve housing. 【0012】 The valve body may have a recess extending from the flat surface to the tapered surface. According to this, contaminants that have flowed between the flat surface and the inner surface of the valve housing can be discharged from the tapered surface side through the recess. 【0013】 The recess may be closed off by the flat surface. According to this, the valve body can ensure airtightness between the inner surface of the valve housing and the outer surface of the valve body. 【0014】 The recess may be a helical groove. According to this, the spiral groove that can be simply configured and has high contamination discharge performance is suitable as the concave portion. 【Brief Description of the Drawings】 【0015】 [Figure 1] It is a cross-sectional view showing the fluid control valve of Example 1 according to the present invention. [Figure 2] (a) is an explanatory view showing an enlarged main valve in the fluid control valve of Example 1, and (b) is an explanatory view showing an enlarged main valve in the fluid control valve of the reference example in which the guide portion on the valve body is composed of only a flat surface. [Figure 3] It is a view showing an enlarged main part in the fluid control valve of Example 1. [Figure 4] (a) is an explanatory view showing an enlarged state in which the main valve is tilted in the fluid control valve of Example 1, and (b) is an explanatory view showing an enlarged state in which the main valve in the fluid control valve of the reference example in which the guide portion on the valve body is composed of only a flat surface is tilted. [Figure 5] It is a cross-sectional view showing the fluid control valve of Example 2 according to the present invention. 【Modes for Carrying Out the Invention】 【0016】 Modes for carrying out the fluid control valve according to the present invention will be described below based on examples. 【Examples】 【0017】 The fluid control valve according to Example 1 will be described with reference to FIGS. 1 to 4. In this example, the fluid control valve used for a shock absorber will be described as an example, but it is also applicable to other uses. Hereinafter, the up and down as viewed from the front of FIG. 1 will be described as the up and down of the fluid control valve. Specifically, the lower side of the paper surface where the main valve 60 is arranged will be described as the lower side of the fluid control valve, and the upper side of the paper surface where the solenoid 80 as a drive source is arranged will be described as the upper side of the fluid control valve. 【0018】 Referring to FIG. 1, the fluid control valve V1 of the present invention is fluidly connected and arranged to the absorber piston chamber P and the reservoir chamber R in the shock absorber A. 【0019】 When the absorber piston moves axially and the pressure of the working fluid in the inflow passage 11 increases, the fluid control valve V1 opens the main valve 60 to allow the working fluid to flow out from the discharge passage 12 into the reservoir chamber R. Thereby, the fluid control valve V1 controls the flow rate of the working fluid flowing from the absorber piston chamber P toward the reservoir chamber R. 【0020】 Also, in the fluid control valve V1, the fluid control characteristics of the main valve 60 are adjusted by the pilot valve 50. 【0021】 Thereby, the fluid control valve V1 controls the damping force in the shock absorber A. 【0022】 As shown in FIG. 1, the fluid control valve V1 is mainly composed of a valve housing 10, a pilot valve 50, a main valve 60, and a solenoid 80. 【0023】 Among these, the pilot valve 50 is arranged at the upper end in the valve housing 10. Also, the main valve 60 is disposed below the pilot valve 50 in the valve housing 10. 【0024】 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 the pilot valve body 51 separates from and contacts the pilot valve seat 40a. 【0025】 The main valve 60 is composed of a piston 61 as a valve body and a main valve seat 45a as a valve seat. The main valve 60 opens and closes when the piston 61 of the main valve 60 separates from and contacts the main valve seat 45a. 【0026】 In FIG. 1, the main valve 60 is shown with its left half in the closed state and its right half in the open state. 【0027】 First, let's explain the configuration on the valve housing 10 side. The elements on the valve housing 10 side are the valve housing 10, the pilot valve 50, and the main valve 60. 【0028】 Referring to Figure 1, the valve housing 10 is formed in an internally stepped cylindrical shape using a metal or resin material. 【0029】 The valve housing 10 has a cylindrical portion 10a, a small-diameter bottomed cylindrical portion 10b, a medium-diameter bottomed cylindrical portion 10c, and a large-diameter bottomed cylindrical portion 10d formed in order from the axial top. 【0030】 A pilot valve body 51 is inserted into the cylindrical portion 10a from the axially upper side. 【0031】 The pilot valve body 51 is formed in a T-shape in cross-section, having a cylindrical portion 52 and a flange portion 53. 【0032】 The cylindrical portion 52 is cylindrical in shape and extends in the axial direction. The lower end of the cylindrical portion 52 is seated on the pilot valve seat 40a. 【0033】 Furthermore, the lower end surface of the rod 83 is in contact with the upper end of the cylindrical portion 52. As a result, the pilot valve body 51, which receives the biasing force of the coil spring 85, is pressed against the rod 83. 【0034】 The flange portion 53 is an annular plate shape that extends outward from the upper end of the cylindrical portion 52. 【0035】 Furthermore, a connecting passage 53a is formed in the flange portion 53, which penetrates in the axial direction. The connecting passage 53a connects the cylindrical portion 10a of the valve housing 10 with the opening 82b of the center post 82. 【0036】 Furthermore, the outer circumferential surface of the flange portion 53 is formed to be movable while sliding in contact with the inner circumferential surface of the cylindrical portion 10a of the valve housing 10. This allows the cylindrical portion 10a to guide the movement of the pilot valve body 51. 【0037】 Returning to the configuration of the valve housing 10, the small-diameter bottomed cylindrical portion 10b is continuous with the cylindrical portion 10a, and its inner side is wider in diameter and recessed axially upward. 【0038】 A pilot valve seat member 40, which is press-fitted from axially downward, is integrally fixed in a nearly sealed state within the small-diameter bottomed cylindrical portion 10b. 【0039】 The pilot valve seat member 40 is formed from a metal or resin material into a circular plate shape having a plurality of communication passages 41 that penetrate in the axial direction. 【0040】 Furthermore, an annular projection 42 is formed at the center of the upper end of the pilot valve seat member 40, projecting upward in the axial direction. The upper end of the annular projection 42 is the pilot valve seat 40a. 【0041】 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 the inner part of the medium-diameter bottomed cylindrical portion 10b is enlarged and recessed axially upward. 【0042】 The piston 61 and the main valve seat 45a are arranged in the medium-diameter bottomed cylindrical section 10c. 【0043】 As shown in Figures 1 and 2(a), the piston 61 includes a guide portion 62, a seal portion 63, and a helical groove 64 as a recess (see Figure 2(a)). 【0044】 As shown in Figure 1, the piston 61 has a funnel-shaped recess 61a that is recessed downward in the axial direction. The recess 61a is open to the upward in the axial direction. The recess 61a is also in communication with the inlet passage 11 through a communication passage 61b formed in the seal portion 63. 【0045】 As shown in Figure 2(a), the outer circumferential surface of the guide portion 62 is composed of a flat surface 65 and a tapered surface 66. Note that in Figure 2(a), only the outer circumferential surface configuration of the piston 61 is illustrated in order to explain the configuration of the outer circumferential surface of the piston 61. The same applies to Figures 2(b), 3, and 4(a)(b). 【0046】 The flat surface 65 extends along the axial direction of the piston 61. Furthermore, the flat surface 65 is continuous in the circumferential direction and has a circular shape when viewed in cross-sectional form in the axial direction. 【0047】 The tapered surface 66 is continuous with the lower end of the flat surface 65 and tapers towards the seal portion 63. Furthermore, the tapered surface 66 is continuous in the circumferential direction and has a circular shape when viewed in cross-section in the axial direction. 【0048】 Furthermore, the tapered surface 66 in this embodiment is an inclined surface with a straight cross-section that extends continuously in the direction of inclination with respect to the axis. The tapered surface may also be an inclined surface with a curved cross-section. 【0049】 Furthermore, the inner diameter D1 of the medium-diameter bottomed cylindrical portion 10c in the valve housing 10 is slightly longer than the maximum outer diameter D2 of the guide portion 62 in the piston 61. 【0050】 As a result, a clearance C is formed between the inner circumferential surface 14 of the medium-diameter bottomed cylindrical portion 10c, which serves as the inner surface of the valve housing 10 (hereinafter simply referred to as "the inner circumferential surface 14 of the valve housing 10") and the flat surface 65 and tapered surface 66 of the guide portion 62. 【0051】 Therefore, the flat surface 65 and tapered surface 66 of the guide portion 62 are movable while sliding against the inner circumferential surface 14 of the valve housing 10. In other words, the medium-diameter bottomed cylindrical portion 10c is able to guide the movement of the piston 61. 【0052】 Furthermore, as shown as the left half of the main valve 60 in Figure 1, when the main valve 60 is in the closed state, the flat surface 65 of the guide portion 62 overlaps with the inner circumferential surface 14 of the valve housing 10 in the radial direction. 【0053】 Furthermore, as shown as the right half of the main valve 60 in Figure 1, when the main valve 60 is in the open state, the flat surface 65 of the guide portion 62 overlaps with the inner circumferential surface 14 of the valve housing 10 in the radial direction. 【0054】 In other words, throughout the entire stroke range of the piston 61, the entire flat surface 65 overlaps radially with the inner circumferential surface 14 of the valve housing 10. 【0055】 This ensures that the fluid control valve V1 can maintain a tight seal between the inner circumferential surface 14 of the valve housing 10 and the guide portion 62 of the piston 61. 【0056】 Furthermore, an annular projection 63a is formed at the lower outer diameter end of the seal portion 63, projecting downward in the axial direction. The annular projection 63a sits on the main valve seat 45a when the main valve 60 is closed. 【0057】 Returning to Figure 2(a), the helical groove 64 extends continuously from the axial center of the flat surface 65 to the axial center of the tapered surface 66. 【0058】 Here, the helical groove 64 will be described in detail. The helical groove 64 extends from an end 64a that is closed at the axial center of the flat surface 65, inclined circumferentially and downward in the axial direction. The helical groove 64 is then closed at an end 64b located at the axial center of the tapered surface 66. 【0059】 In other words, the helical groove 64 is closed in the axial direction on the piston 61. This ensures a tight seal between the inner circumferential surface 14 of the valve housing 10 and the guide portion 62 on the piston 61. 【0060】 Furthermore, in the axial direction, the end portion 64a on the flat surface 65 and the end portion 64b on the tapered surface 66 of the helical groove 64 overlap in the axial direction. In other words, the helical groove 64 extends over approximately one full turn in the circumferential direction. 【0061】 Returning to Figure 1, a coil spring 67 is positioned between the pilot valve seat member 40 and the piston 61 as a biasing means for biasing the piston 61 in the valve closing direction. More specifically, the lower end of the coil spring 67 is inserted into the recess 61a of the piston 61. 【0062】 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 of 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 body 51, and the piston 61. 【0063】 Returning to the configuration of the valve housing 10, the large-diameter bottomed cylindrical portion 10d is continuous with the medium-diameter bottomed cylindrical portion 10c, and the inner part is wider in diameter than the medium-diameter bottomed cylindrical portion 10c and recessed in the axial direction upward. 【0064】 The main valve seat member 45 is fixed in a nearly sealed state by being press-fitted into the large-diameter bottomed cylindrical portion 10d from axially downward. 【0065】 The main valve seat member 45 is formed from a metal or resin material in the shape of an annular plate having an inlet passage 11 that penetrates it axially. The main valve seat member 45 is press-fitted and fixed in a sealed state into the large-diameter bottomed cylindrical portion 10d from below in the axial direction via a gasket. 【0066】 Furthermore, the main valve seat member 45 has a cylindrical portion 46 that extends in the axial direction. The upper end of the cylindrical portion 46 is the main valve seat 45a. 【0067】 Returning to Figure 1, the outer surface of the valve housing 10 has an L-shaped communication groove 10e that extends downward in cross-sectional view from the upper end to the side of the cylindrical portion 10a. 【0068】 Furthermore, the lower end of the communication groove 10e is located below the opening 81b in the casing 81 and is open in the outer diameter direction. 【0069】 As a result, the communication groove 10e constitutes the pilot-side discharge passage 13 of the pilot valve 50. 【0070】 More specifically, the pilot-side discharge passage 13 is composed of a cylindrical portion 10a, a small-diameter bottomed cylindrical portion 10b, a communication groove 10e in the valve housing 10, an annular projection 42 in the pilot valve seat member 40, an opening 81b in the casing 81, and an opening 82b in the center post 82. 【0071】 Furthermore, the valve housing 10 has a discharge passage 12 that extends outward from the medium-diameter bottomed cylindrical portion 10c and connects the inside of the medium-diameter bottomed cylindrical portion 10c with the reservoir chamber R. 【0072】 Next, the solenoid 80 will be described. The solenoid 80 is connected to the valve housing 10 and applies driving force to the pilot valve body 51. 【0073】 The solenoid 80 mainly consists of a casing 81, a center post 82, a rod 83, a movable iron core 84, a coil spring 85, a coil 86, a sleeve 87, and bearings 88 and 89. 【0074】 The casing 81 includes a stepped cylindrical main body portion 81a into which the center post 82 is inserted and fixed from axially below. 【0075】 Furthermore, the casing 81 has an opening 81b that is continuous with the lower end of the main body portion 81a and opens downwards. 【0076】 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. 【0077】 The center post 82 has a cylindrical body portion 82a that extends in the axial direction. A bearing 89 is inserted and fixed into the body portion 82a from above in the axial direction. 【0078】 Furthermore, the center post 82 has an opening 82b that is continuous with the lower end of the main body portion 82a and opens to the lower side of the center post 82. 【0079】 The rod 83 is formed in a cylindrical shape. The rod 83 is inserted through the center post 82 and is arranged to reciprocate freely in the axial direction. 【0080】 Furthermore, the rod 83 is inserted into and fixed to the movable iron core 84. As a result, when the solenoid 80 is energized, the rod 83 moves in conjunction with the movable iron core 84, which moves in the valve closing direction. Consequently, the rod 83 moves the pilot valve body 51 in the valve closing direction, i.e., axially downward. 【0081】 Furthermore, the upper end of the rod 83 is inserted into bearing 88, and the lower end is inserted into bearing 89. These bearings 88 and 89 guide the axial movement of the rod 83. As a result, the rod 83 is less likely to tilt radially during axial movement. 【0082】 The coil spring 85 is positioned between the pilot valve seat member 40 and the pilot valve body 51. 【0083】 The coil spring 85 biases the pilot valve body 51 in the opening direction of the pilot valve 50, that is, axially upward. 【0084】 Coil 86 is an excitation coil wound around the outside of the center post 82 via a bobbin. 【0085】 The sleeve 87 is formed in a bottomed cylindrical shape. A bearing 88, which guides the movement of the rod 83, is fitted and fixed to the sleeve 87. 【0086】 Next, the operation of the fluid control valve V1, mainly the opening and closing operations of the pilot valve 50 and the main valve 60, will be explained with reference to Figures 1 to 4. 【0087】 First, the fluid control valve V1 in the de-energized state will be described. Referring to Figure 1, in the de-energized state, the pilot valve 50 has its pilot valve body 51 pressed axially upward by the biasing force of the coil spring 85. As a result, the pilot valve body 51 separates from the pilot valve seat 40a, and the pilot valve 50 is open. The pilot valve opening degree at this time is the maximum in this embodiment. 【0088】 When the shock absorber A is activated in the de-energized state and the pressure of the working fluid in the inlet passage 11 increases, the working fluid flows through the communication passage 61b in the piston 61 and the pilot control chamber S, and into the reservoir chamber R from the pilot-side discharge passage 13. In addition, as will be explained below, depending on the pressure of the working fluid, working fluid may also flow into the reservoir chamber R from the discharge passage 12. 【0089】 The fluid control valve V1 has a narrow flow path cross-sectional area in the communication passage 61b of the piston 61. Therefore, even if the pressure of the working fluid in the inlet passage 11 increases, the pressure of the working fluid in the pilot control chamber S does not increase immediately in response to the pressure of the working fluid in the inlet passage 11. As a result, a pressure difference occurs between the pressure of the working fluid in the inlet passage 11 and the pressure of the working fluid in the pilot control chamber S. The larger this pressure difference becomes, the easier it is for the main valve 60 to open. 【0090】 In the following explanation, the pressure of the working fluid in the inlet passage 11 will be referred to as "pressure Pin in the inlet passage 11," and the pressure of the working fluid in the pilot control room S will be referred to as "pressure Ps in the pilot control room S." 【0091】 After the main valve 60 is opened, when the differential pressure ΔP (= Pin - Ps) between the pressure Pin in the inflow passage 11 and the pressure Ps in the pilot control chamber S becomes small, the main valve 60 closes. 【0092】 The factors for the differential pressure ΔP to become small are that the working fluid flows from the discharge passage 12 into the reservoir chamber R through the main valve 60 and the pressure Pin in the inflow passage 11 becomes small, the working fluid flows from the communication passage 61b into the pilot control chamber S and the pressure Pin in the inflow passage 11 becomes small, the volume decreases due to the movement of the piston 61 and the pressure Ps in the pilot control chamber S increases, etc. Hereinafter, the opening and closing operation of the main valve 60 will be described in more detail with specific examples. 【0093】 Referring to the left half of FIG. 1, for example, when the pressure Pin in the inflow passage 11 is less than the small P1 (Pin < P1), such as when the shock absorber piston in the shock absorber A reciprocates with a minute stroke when traveling on a smooth road surface, the piston 61 has its seal portion 63 seated on the main valve seat 45a by the biasing force of the coil spring 67. That is, the main valve 60 is closed. 【0094】 Referring to the right half of FIG. 1, when the pressure Pin in the inflow passage 11 is greater than or equal to P2 (P2 ≧ P1), such as when the shock absorber piston in the shock absorber A reciprocates with a small stroke when traveling on a rough road surface, the piston 61 moves upward in the axial direction against the biasing force of the coil spring 67. 【0095】 That is, the seal portion 63 of the piston 61 is separated from the main valve seat 45a, and the main valve 60 is opened. Thereby, the working fluid flows from the discharge passage 12 into the reservoir chamber R. 【0096】 At this time, as the piston 61 moves, the surplus working fluid in the pilot control chamber S flows from the pilot side discharge passage 13 into the reservoir chamber R. 【0097】 As described above, the main valve 60 closes as the differential pressure ΔP decreases. Therefore, the valve opening degree of the main valve 60 increases as the pressure Pin in the inflow passage 11 approaches the large P3 (P3 > P2). 【0098】 Similarly, for example, when the absorber piston in the shock absorber A attempts to have a large stroke to overcome a step on the road surface, even when the pressure Pin in the inflow passage 11 is greater than or equal to the large P3 (Pin ≧ P3), the piston 61 moves upward in the axial direction against the biasing force of the coil spring 67. 【0099】 As a result, since the main valve 60 is opened, the working fluid flows from the discharge passage 12 into the reservoir chamber R. Further, the surplus working fluid in the pilot control chamber S flows from the pilot side discharge passage 13 into the reservoir chamber R. 【0100】 Note that the valve opening degree of the main valve 60 when the pressure Pin in the inflow passage 11 is greater than (Pin > P3) is the maximum in this embodiment. 【0101】 Thereafter, the working fluid flows from the discharge passage 12 into the reservoir chamber R through the main valve 60. As the pressure Pin in the inflow passage 11 decreases, the coil spring 67 extends and the valve opening degree decreases. When the pressure Pin in the inflow passage 11 becomes less than the small (Pin < P1), the seal portion 63 of the piston 61 seats on the main valve seat 45a and the main valve 60 is closed. 【0102】 Next, regarding the fluid control valve V1 in the energized state, mainly the control of the damping force by the pilot valve 50 will be described. Note that since the main valve 60 operates substantially the same as in the non-energized state even in the energized state, its description will be omitted. 【0103】 Referring to FIG. 1, in the energized state (i.e., during so-called duty control), when the electromagnetic force generated by applying a current to the solenoid 80 exceeds the biasing force of the coil spring 85, the movable iron core 84 is attracted toward the center post 82 side, i.e., the lower side in the axial direction. 【0104】 As a result, the rod 83 fixed to the movable iron core 84 moves together with the pilot valve body 51 in an axial downward direction. In response, the pilot valve 50 becomes less open and closes when a current exceeding a predetermined level is supplied. 【0105】 If the pilot valve is open at a smaller opening compared to the non-energized state, the working fluid in the inlet passage 11 flows into the reservoir chamber R from the pilot-side discharge passage 13 as the shock absorber A operates, similar to the non-energized state. Also, as described above, depending on the pressure Pin in the inlet passage 11, the working fluid may also flow into the reservoir chamber R from the discharge passage 12. 【0106】 Furthermore, the smaller the pilot valve opening, the less likely the working fluid is to flow from the pilot control chamber S into the pilot-side discharge passage 13. As a result, the pressure difference ΔP between the pressure Pin in the inlet passage 11 and the pressure Ps in the pilot control chamber S becomes less likely, and the main valve 60 becomes less likely to open. In other words, the damping force in the shock absorber A can be increased. 【0107】 In other words, the damping force in shock absorber A is minimized when the pilot valve opening is at its maximum. That is, the damping force is controlled to be the smallest when the fluid control valve V1 is de-energized. 【0108】 Furthermore, even if the main valve 60 is opened, the smaller the pilot valve opening in the pilot valve 50, the faster the differential pressure ΔP decreases. In other words, the time the main valve 60 is open is shortened as the pilot valve opening in the pilot valve 50 decreases. 【0109】 Based on these factors, the fluid control characteristics in the main valve 60 are controlled according to the pilot valve opening degree in the pilot valve 50. This allows the fluid control valve V1 to variably control the damping force in the shock absorber A. 【0110】 Even when a current exceeding a predetermined level is supplied and the pilot valve 50 is closed, if a high pressure Pin is generated in the inflow passage 11, this working fluid will slightly open the pilot valve 50. As a result, the working fluid flows from the pilot-side discharge passage 13 into the reservoir chamber R, just as in the unpowered state. 【0111】 Thus, when the pilot valve 50 is closed while energized, the fluid control valve V1 is in a state where the working fluid is least likely to pass through the pilot valve 50, and the main valve 60 is less likely to open. Therefore, the fluid control valve V1 can maximize the damping force in the shock absorber A. 【0112】 The current value supplied to the coil 86 that constitutes the solenoid 80 is set based on input parameters such as vehicle speed, vehicle acceleration / deceleration, steering angle, road surface conditions, and sprung weight. 【0113】 Furthermore, the pilot valve 50, which is in an open state, may be closed if a current value exceeding a predetermined value is set. 【0114】 Next, the state of the piston 61 during movement will be explained in more detail with reference to Figures 2 to 4. Note that in Figures 2 to 4, for the sake of explanation, the flat surface 65 and tapered surface 66 of the guide portion 62, and the clearance C between the inner circumferential surface 14 of the valve housing 10 and the guide portion 62 of the piston 61 are exaggerated in the illustration. 【0115】 First, we will describe the normal state in which the piston 61 moves approximately parallel to the axis of the valve housing 10 (hereinafter simply referred to as the "normal state"). Next, we will describe the state in which the piston 61 moves while tilted (see Figure 4). 【0116】 As shown in Figure 2(a), in the normal state, a clearance C of approximately the same dimension is formed in the circumferential direction between the inner circumferential surface 14 of the valve housing 10 and the flat surface 65 of the guide portion 62 of the piston 61. 【0117】 Lubricants such as oil and working fluids flow into clearance C. 【0118】 This allows the piston 61 to move smoothly in the axial direction along the axis of the valve housing 10. 【0119】 In this case, the piston 61 has a smooth tapered surface 66 without any irregularities. Therefore, the piston 61 can move smoothly relative to the valve housing 10. 【0120】 Furthermore, the radial dimension L1, or so-called sinusoidal length, of the tapered surface 66 is smaller than the radial dimension L2 of the clearance C under normal conditions (L1 <L2)。 【0121】 Even if vibrations, disturbances, etc., accompanying the movement of the piston 61 cause the piston 61 to tilt slightly, the tapered surface 66 can guide the movement of the piston 61. Furthermore, the tapered surface 66 of the piston 61 is a smooth surface without irregularities. Therefore, the piston 61 can slide smoothly against the valve housing 10. 【0122】 Here, referring to Figure 2(b), we will describe the piston 61A (hereinafter simply referred to as "piston 61A" or "comparative piston 61A") that constitutes the main valve 60A in the fluid control valve of the reference example. The guide portion 62A of piston 61A is composed solely of a flat surface 65A. Furthermore, the other components of piston 61A are substantially the same as those of piston 61. 【0123】 There is a clearance C between the inner circumferential surface 14 of the valve housing 10 and the flat surface 65A of the guide portion 62A of the piston 61A, through which lubricant such as oil or working fluid flows. This allows the piston 61A to move along the axis of the valve housing 10, just like the piston 61. 【0124】 Next, the tilting of the piston 61 in this embodiment will be described in detail. 【0125】 Furthermore, since the piston 61 is configured to move while being guided by the inner circumferential surface 14 of the valve housing 10 in response to the biasing force and differential pressure from the coil spring 67, it is more prone to tilting compared to the pilot valve body 51, which moves integrally with the rod 83, which moves while being guided by the bearings 88 and 89. 【0126】 As shown in Figure 3, the radial dimension L1 at the tapered surface 66 is smaller than the dimension L2 of the clearance C under normal conditions (L1 <L2)。 【0127】 Furthermore, the axial dimension L3 of the flat surface 65 is approximately the same as the axial dimension L4 of the tapered surface 66 (L3 = L4). 【0128】 As shown in Figure 4(a), the piston 61 is tiltable until the upper end of the flat surface 65 and the lower end of the tapered surface 66 located diagonally opposite the upper end come into contact with the inner circumferential surface 14 of the valve housing 10. 【0129】 The upper end of the flat surface 65 is the corner 65a and its vicinity. The lower end of the tapered surface 66 is the corner 66a and its vicinity. The corners 65a and 66a may be rounded, such as R-shaped surfaces, in which case, when the piston 61 tilts, the R-shaped surface or its vicinity will come into contact with the inner circumferential surface 14 of the housing 10. 【0130】 In other words, with respect to the axis Ax1 of the valve housing 10, which is shown by the dashed line in Figure 4(a), the axis Ax2 of the piston 61, also shown by the dashed line in Figure 4(a), can tilt up to an angle θ1. 【0131】 As a result, when the piston 61 tilts, the corners 65a and 66a are less likely to make contact with the inner circumferential surface 14 of the valve housing 10. This prevents wear of the corners 65a and 66a, and prevents the corners 65a and 66a from contacting and damaging the inner circumferential surface 14 in the fluid control valve V1. Furthermore, in this embodiment, when the piston 61 tilts, the tapered surface 66 is aligned with the inner circumferential surface 14 of the valve housing 10, so the corner 66a is less likely to make contact than the corner 65a. 【0132】 Furthermore, the corner 65b between the flat surface 65 and the tapered surface 66 is less likely to come into contact with the inner circumferential surface 14 of the valve housing 10. As a result, the helical groove 64 that crosses a portion of the corner 65b is less likely to come into contact with the inner circumferential surface 14, thus preventing damage. 【0133】 The various dimensions of the piston 61 may be changed as appropriate. However, from the viewpoint of protecting the helical groove 64, it is preferable that the corner 65b is spaced apart from the flat surface 65 in order to prevent corner contact. 【0134】 Furthermore, as shown in Figure 2, the minimum outer diameter D3 of the tapered surface 66 is larger than the outer diameter D4 of the seal portion 63 (D3 > D4). In addition, as shown in Figure 3, the outer diameter end of the seal portion 63 is located on the inner diameter side of the hypothetical extension line VL1 of the tapered surface 66 in the radial direction. 【0135】 As a result, the seal portion 63 of the piston 61 is prevented from contacting the inner circumferential surface 14 of the valve housing 10 before the tapered surface 66 contacts the inner circumferential surface 14 of the valve housing 10. Therefore, the piston 61 can easily tilt within a range where the seal portion 63 is less likely to contact and damage the inner circumferential surface 14 of the valve housing 10. 【0136】 Here, the tilting of the piston 61A as a comparison target will be described. As shown in FIG. 4(b), the piston 61A as a comparison target is tiltable until the upper end portion on the flat surface 65A and the lower end portion on the flat surface 65A located on the diagonal line of the upper end portion contact the inner peripheral surface 14 in the valve housing 10. 【0137】 Note that the upper end portion on the flat surface 65A is a portion that is continuous with the corner 62Aa between the upper end surface of the piston 61A and the flat surface 65A on the flat surface 65A. Further, the lower end portion on the flat surface 65A is a portion that is continuous with the corner 62Ab between the lower end surface of the guide portion 62A and the flat surface 65A on the flat surface 65A. 【0138】 In other words, with respect to the axis Ax1 in the valve housing 10 indicated by the dashed line in FIG. 4(b), the axis Ax3 in the piston 61A indicated by the dashed line in FIG. 4(b) is tiltable up to an angle θ2. 【0139】 As described above, the radial dimension L1 of the tapered surface 66 is smaller than the dimension L2 of the clearance C (L1 < L2). From this, in the piston 61 of the present embodiment, a space H between the inner peripheral surface 14 and the tapered surface 66 in the valve housing 10 that is wider than the clearance C and narrower than twice thereof is formed between the outer diameter side of the tapered surface 66 and the virtual extension line VL2 of the flat surface 65 (L2 < H = L1 < 2×L2). 【0140】 Thereby, the piston 61 in the present embodiment is tiltable more greatly than the piston 61A as a comparison target. That is, the tiltable angle θ1 of the piston 61 in the present embodiment is larger than the tiltable angle θ2 of the piston 61A as a comparison target (θ1 > θ2). 【0141】 Next, we will describe the pistons 61 and 61A in a state where contaminants are trapped between the inner circumferential surface 14 of the valve housing 10 and the flat surface 65 of the guide portion 62 of the piston 61 (hereinafter simply referred to as the "trapped state"). 【0142】 Referring to Figure 4, in the jammed state, pistons 61 and 61A may tilt with the jammed contaminant as the pivot point. 【0143】 In this case, with piston 61A, which has a small tiltable angle θ2, it is difficult to obtain an opening large enough to adequately discharge contaminants. Therefore, it is difficult to discharge trapped contaminants with piston 61A. 【0144】 In contrast, the piston 61 of the present invention, which has a large tiltable angle θ1, makes it easier to obtain an opening large enough to adequately discharge contaminants. Therefore, the piston 61 facilitates the discharge of trapped contaminants. 【0145】 Furthermore, even when tilted at an angle θ1, the piston 61 can slide smoothly against the valve housing 10 as described above. 【0146】 Furthermore, regardless of whether pistons 61 and 61A are tilted in the engaged state, the contaminant may move relative to pistons 61 and 61A as they move. 【0147】 In this case, with the piston 61A used as a comparison, the jammed state continues until the contaminant moves outside the flat surface 65A due to its relative movement with respect to the piston 61A. 【0148】 In contrast, the piston 61 of the present invention has a helical groove 64 that is recessed toward the inner diameter side. As a result, contaminants flow into the helical groove 64, and the piston 61 is freed from jamming. 【0149】 Furthermore, as described above, the helical groove 64 extends with an inclination downward in the axial direction and extends over approximately one full turn in the circumferential direction. In other words, the helical groove 64 has a wide area in which contaminants can be recovered in both the circumferential and axial directions. 【0150】 Therefore, as the piston 61 moves, the contaminants move relative to the piston 61, mainly in the axial direction, allowing the helical groove 64 to efficiently collect contaminants located in axially offset positions. 【0151】 Furthermore, the piston 61 is rotatable in the circumferential direction. Therefore, as the piston 61 rotates with axial movement, the helical groove 64 can efficiently collect contaminants located at circumferentially offset positions. 【0152】 Furthermore, the helical groove 64 extending to the tapered surface 66 easily introduces contaminants into the gap G (see Figure 2(a)) between the inner circumferential surface 14 and the tapered surface 66 in the valve housing 10. The gap G is composed of a clearance C and space H (G > C). 【0153】 Furthermore, the gap G (see Figure 2(a)) is open to the discharge passage 12 side. 【0154】 Furthermore, as described above, the space between the flat surface 65 of the piston 61 and the inner circumferential surface 14 of the valve housing 10 is sealed over the entire stroke range of the piston 61. Therefore, the working fluid that flows into the inlet passage 11 moves toward the discharge passage 12. 【0155】 As a result, contaminants discharged into the gap G (see Figure 2(a)) are more easily discharged outside the fluid control valve V1 through the discharge passage 12. [Examples] 【0156】 Next, the fluid control valve according to Example 2 will be described with reference to Figure 5. Note that the description of components that are identical to those in Example 1 and therefore redundant will be omitted. 【0157】 In this embodiment 2, the fluid control valve V2 consists of a main valve 160 comprising a piston 161 as the valve body, a main valve seat 45a, and a bellows 70. 【0158】 The piston 161 has a cylindrical recess 161a formed in the axial direction downward. The recess 161a is open to the axial direction upward. The recess 161a is also in communication with the inlet passage 11 through a communication passage 61b formed in the seal portion 63. 【0159】 Furthermore, the piston 161 includes a base portion 162 and a seal portion 63. 【0160】 The base portion 162 is formed in a cylindrical shape. Furthermore, the outer diameter of the base portion 162 is smaller than the outer diameter of the seal portion 63. That is, the seal portion 63 protrudes outward from the outer circumferential surface of the base portion 162 in a flange-like manner. 【0161】 The upper end of the bellows 70 is fixed to the corner of the medium-diameter bottomed cylindrical portion 10c of the valve housing 10. The lower end of the bellows 70 is fixed to the outer diameter side end of the seal portion 63. 【0162】 Furthermore, a sufficient gap is formed between the bellows 70 and the inner circumferential surface 14 of the valve housing 10 so that the bellows 70 is less likely to come into contact with the inner circumferential surface 14 when the piston 161 moves. 【0163】 As a result, the piston 161 is able to move in the axial direction while its tilting is suppressed by the bellows 70. 【0164】 Furthermore, malfunctions caused by contaminants getting caught between the inner circumferential surface 14 of the valve housing 10 and the piston 161 are prevented. 【0165】 Although embodiments of the present invention have been described above with reference to the drawings, the specific configurations are not limited to these embodiments, and any changes or additions that do not depart from the spirit of the present invention are also included. 【0166】 For example, in each of the embodiments described above, the fluid control valve was described as having a pilot valve and a main valve, but it is not limited to this configuration and may consist of only a main valve. 【0167】 Furthermore, although the inlet and outlet passages in the housing were described in the above embodiments as being configured for the flow of working fluid, the invention is not limited to this configuration. Connectors may be connected to the inlet and outlet passages in the housing, and the working fluid may flow into the housing through these connectors. In other words, it is not limited to the direct flow of working fluid; the inlet and outlet passages can be configured to allow working fluid to flow into or out of the housing. 【0168】 Furthermore, although the valve seat in each of the above embodiments was described as being formed as a valve seat member separate from the valve housing, the configuration is not limited to this, and it may be formed integrally with the valve housing. 【0169】 Furthermore, although the valve housing was described in the above embodiments as being formed in a cylindrical shape, it is not limited to this and may be polygonal or cylindrical, and its shape may be changed as appropriate. In other words, the inner surface of the valve housing is not limited to an inner circumferential surface that is circular in axial view, but may also be an inner surface that is polygonal in axial view. 【0170】 Furthermore, the inner surface of the valve housing may be divided in the circumferential direction by grooves extending in the axial direction or the like. In other words, the inner surface of the valve housing may be discontinuous in the circumferential direction. 【0171】 Furthermore, although the valve body was described in each of the above embodiments as a piston formed in the shape of a bottomed cylindrical shape, it is not limited to this and may be a bottomed polygonal cylindrical shape, and its shape may be changed as appropriate. In other words, the flat surface and tapered surface of the valve body are not limited to a circular shape in the axial view, but may also be polygonal in the axial view. 【0172】 Furthermore, although the flat surface and tapered surface of the valve body were described as being continuous in the circumferential direction in each of the above embodiments, the configuration is not limited to this, and they may be separated in the circumferential direction by grooves extending in the axial direction or the like. In other words, the flat surface and tapered surface of the valve body may be discontinuous in the circumferential direction. 【0173】 Furthermore, although the outer circumferential surface of the guide portion was described as being composed of a flat surface and a tapered surface in each of the above embodiments, the invention is not limited to this, and another tapered surface may be formed on the axially upward side of the flat surface, or a groove extending in the circumferential direction may be formed between the flat surface and the tapered surface of the valve body, and these may be modified as appropriate. 【0174】 Furthermore, although the tapered surface of the valve body was described as an inclined surface in each of the above embodiments, it is not limited to this configuration and may be formed in a stepped shape consisting of multiple steps, or it may be part of a spherical shape, and may be modified as appropriate. 【0175】 Furthermore, although the recesses in the above embodiments were described as being spiral grooves, they are not limited to this configuration and may be appropriately modified to include grooves extending in the axial direction, grooves extending in the radial direction, recesses recessed in the inner diameter direction and open to the outer diameter side, etc. 【0176】 Furthermore, although the above embodiments have described the recess as being a single helical groove, the configuration is not limited to this, and multiple recesses may be formed. 【0177】 Furthermore, although the helical grooves in the above embodiments were described as extending over approximately one full turn in the circumferential direction, they are not limited to this configuration and may extend for more than one turn. For example, if the grooves extend for more than one turn on a flat surface, it becomes possible to recover contaminants over the entire circumferential area of ​​the flat surface. 【0178】 Furthermore, although the helical grooves in the above embodiments were described as extending approximately one full turn in the circumferential direction, the configuration is not limited to this, and may extend for less than one full turn in the circumferential direction. In this case, it is preferable that multiple helical grooves extending for less than one full turn in the circumferential direction are formed in the circumferential direction. 【0179】 Furthermore, although the configuration described uses a coil spring as the biasing means for biasing the piston in the valve closing direction, it is not limited to this, and may be a tension spring, a pressure different from the pressure in the inlet passage, or various types of cylinders, etc. [Explanation of symbols] 【0180】 10 Valve Housing 11 Inflow channel 12 Exhaust channel 14 Inner peripheral surface (inner surface) 60 Main Officer 61 Piston (valve body) 62 Guide section 63 Seal part 64 Spiral groove 65 Flat surface 66 Tapered surface 67 Coil spring (biasing means) 70 Bellows 160 Main Valance 161 Piston 162 Base section Ax1~Ax3 axis center C Clearance V1 Fluid control valve V2 Fluid Control Valve θ1,θ2 angle

Claims

[Claim 1] A fluid control valve comprising: a valve housing having an inlet passage and an outlet passage; a valve seat disposed between the inlet passage and the outlet passage; and a valve body having a guide portion guided by the inner surface of the valve housing and a sealing portion that moves away from the valve seat, The guide portion of the valve body has a flat surface and a tapered surface that narrows toward the seal portion, and the flat surface extends in the axial direction of the valve body. The inner surface of the valve housing extends in the axial direction of the valve housing, The valve body has a recess formed therein, extending from the flat surface to the tapered surface. The recess is closed on the flat surface, ensuring airtightness between the inner surface of the valve housing and the guide portion in this fluid control valve. [Claim 2] The fluid control valve according to claim 1, wherein the outer dimensions of the valve body are greater at the tapered surface portion than at the sealing portion portion. [Claim 3] The fluid control valve according to claim 1, wherein the tapered surface is an inclined surface. [Claim 4] The fluid control valve according to any one of claims 1 to 3, wherein the recess is a helical groove.

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