Damping force regulating valve and damping-force-adjusting shock absorber

Abstract

A damping force generation device 50 comprises: a structural member in which is formed a through hole that penetrates therethrough in the axial direction; a first valve body which is provided so as to face one opening of the through hole in the axial direction, the distance between the first valve body and said one opening being adjustable by an actuator; a back pressure chamber which has an internal pressure that is adjusted with the axial position of the first valve body; a second valve body which receives a pressure in the valve closing direction due to the internal pressure, which has a communication hole in communication with the back pressure chamber at a position that is offset from the center axis of the other opening of the through hole, and which is guided by a guide member to move in the axial direction; and a valve seat on which the second valve body can be seated.

Description

Damping force adjustment valve, damping force adjustable shock absorber

[0001] The present invention relates to a damping force control valve and a damping force control shock absorber.

[0002] For example, the device described in Patent Document 1 includes a valve member that is axially movable relative to a housing, a valve seat, and a pilot valve. The pilot valve has a pilot valve seat and a pilot valve body.

[0003] EP3988816

[0004] As in the device described in Patent Document 1, if the axial positions of the orifice formed in the first valve body (the valve member in Patent Document 1) for introducing oil into the pilot valve and the pilot passage opened and closed by the second valve body (the pilot valve body in Patent Document 1) coincide, there is a risk that the second valve body will open unintentionally due to oil passing through the orifice. The present invention aims to provide a damping force control valve etc. that can prevent the second valve body from opening unintentionally due to oil passing through the orifice formed in the first valve body.

[0005] The present invention, which was completed with this object in mind, is a damping force control valve comprising: a structural member in which a through hole passing through in the axial direction is formed; a first valve body provided axially opposite one opening of the through hole and the distance from the one opening being adjustable by an actuator; a back pressure chamber whose internal pressure is adjusted by the axial position of the first valve body; a second valve body which is pressurized in a valve closing direction by the internal pressure, has a communication hole communicating with the back pressure chamber at a position offset from the central axis of the other opening of the through hole, and moves axially while being guided by a guide member; and a valve seat on which the second valve body can be seated.

[0006] According to the present invention, it is possible to prevent the second valve body from opening unintentionally due to oil passing through the orifice formed in the first valve body.

[0007] FIG. 1 is a diagram showing an example of a schematic configuration of a suspension device according to the first embodiment; FIG. 2 is a diagram showing an example of a cross section of a damping force generating device according to the first embodiment; FIG. 3 is a diagram showing an example of a perspective cross section of a portion of a main valve unit and a damping force adjusting unit according to the first embodiment; FIG. 4 is a diagram showing an example of a partial cross section of a portion of a main valve unit and a damping force adjusting unit according to the first embodiment; FIG. 5 is a diagram showing an example of a portion of a seal member; FIG. 6 is a diagram showing an example of an oil flow when the piston unit moves at a low speed in a state where the pressing force of the pressing member is set to the smallest; FIG. 7 is a diagram showing an example of an oil flow when the piston unit moves at a high speed in a state where the pressing force of the pressing member is set to the smallest; FIG. 8 is a diagram showing an example of an oil flow when the piston unit moves at a low speed in a state where the pressing force of the pressing member is set to the largest; FIG. 9 is a diagram showing an example of an oil flow when the piston unit moves at a high speed in a state where the pressing force of the pressing member is set to the largest;

[0008] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. <First Embodiment> Fig. 1 is a diagram showing an example of the schematic configuration of a suspension system 1 according to a first embodiment. The suspension system 1 is a suspension used in four-wheeled vehicles such as passenger automobiles, and as shown in Fig. 1, includes a hydraulic shock absorber 2 and coil springs 3 arranged on the outside of the shock absorber 2. The suspension system 1 also includes a lower spring seat 4 that supports one axial end (lower side in Fig. 1) of a rod 20 (described later) of the coil spring 3, and an upper spring seat 5 that supports the other axial end (upper side in Fig. 1) of the coil spring 3.

[0009] The suspension 1 also includes a vehicle body bracket 6 for mounting the suspension 1 to a vehicle, a wheel side bracket 7 for mounting the suspension 1 to a wheel, and a dust cover 8 for covering at least a portion of the cylinder portion 10 and the rod 20. Hereinafter, the axial direction of the rod 20 may be simply referred to as the "axial direction." One side in the axial direction (the lower side in FIG. 1 ) and the other side in the axial direction (the upper side in FIG. 1 ) may be simply referred to as the "one side" and the "other side," respectively. A direction intersecting the axial direction (for example, a perpendicular direction) is referred to as the "radial direction." In the radial direction, the side of the center line of the cylinder 11 may be simply referred to as the "inner side," and the side away from the center line may be simply referred to as the "outer side."

[0010] The shock absorber 2 includes a cylinder portion 10 that stores oil, and a rod 20 that has one side that protrudes from the cylinder portion 10 and one side that is slidably inserted into the cylinder portion 10. The shock absorber 2 also includes a piston portion 30 that is provided at one end of the rod 20, and a bottom portion 40 that is provided at one end of the cylinder portion 10. The shock absorber 2 also includes a damping force generating device 50 that is provided outside the cylinder portion 10 and generates a damping force.

[0011] The cylinder section 10 has a cylinder 11 that stores oil, an outer cylinder body 12 that is provided on the outside of the cylinder 11, and a damper case 13 that is provided on the outside of the cylinder 11 and further outside the outer cylinder body 12. The cylinder section 10 also has a rod guide section 14 that movably supports the rod 20, a bump stopper cap 15, and an oil seal 16 that prevents foreign matter from entering the cylinder section 10.

[0012] The cylinder 11 is formed in a cylindrical shape, and a communication hole 11H that connects the inside to the outside is formed at the other end. The outer cylinder body 12 is also formed in a cylindrical shape. The outer cylinder body 12 forms a communication path L between the cylinder 11 and itself. The outer cylinder body 12 also has an outer cylinder body opening 12H and an outer connection part 12J at a position facing the damping force generator 50. The outer connection part 12J has an oil flow path and protrudes outward to form a connection point with the damping force generator 50.

[0013] The damper case 13 is formed in a cylindrical shape. A reservoir chamber R in which oil is stored is formed between the damper case 13 and the outer cylinder body 12. The reservoir chamber R absorbs oil from the cylinder 11 and supplies oil to the cylinder 11 as the rod 20 moves relative to the cylinder 11. The reservoir chamber R also stores oil that flows out from the damping force generator 50. The damper case 13 also has a case opening 13H at a position facing the damping force generator 50.

[0014] The rod 20 is a rod-shaped member that extends long in the axial direction. One side of the rod 20 holds the piston portion 30. The other side of the rod 20 is connected to, for example, the vehicle body via a connecting member or the like (not shown).

[0015] The piston portion 30 includes a piston body 31 having a plurality of piston oil passage ports 311, a piston valve 32 that opens and closes the other side of the piston oil passage ports 311, and a spring 33 that is provided between the piston valve 32 and one end of the rod 20. The piston portion 30 divides the oil in the cylinder 11 into a first oil chamber Y1 and a second oil chamber Y2.

[0016] The bottom portion 40 has a valve seat 41, a check valve portion 43 provided on the other side of the valve seat 41, and a fixing member 44 provided in the axial direction. The bottom portion 40 separates the first oil chamber Y1 from the reservoir chamber R.

[0017] [Configuration and Function of Damping Force Generator 50] Fig. 2 is a diagram showing an example of a cross section of the damping force generator 50 of the first embodiment. Fig. 3 is a diagram showing an example of a perspective cross section of a portion of the main valve unit 51 and the damping force adjuster 60 of the first embodiment. Fig. 4 is a diagram showing an example of a partial cross section of a portion of the main valve unit 51 and the damping force adjuster 60 of the first embodiment. Fig. 5 is a diagram showing an example of a portion of the seal member 55.

[0018] In the following description, the longitudinal direction of the damping force generator 50 shown in FIG. 2 (i.e., a direction intersecting (e.g., a direction substantially perpendicular to) the axial direction of the cylinder portion 10 (see FIG. 1)) may be referred to as the "second axial direction." In addition, the central axis side of the cylinder portion 10 in the second axial direction (the lower side of the damping force generator 50 in FIG. 2) may be referred to as the "first side," and the side away from the central axis of the cylinder portion 10 (the upper side of the damping force generator 50 in FIG. 2) may be referred to as the "second side." In addition, the lateral direction of the damping force generator 50 shown in FIG. 2 (i.e., a direction intersecting the second axial direction) may be referred to as the "second radial direction." In addition, in the second radial direction, the central axis side along the second axial direction may be referred to as the "second inner side," and the side away from the central axis along the second axial direction may be referred to as the "second outer side."

[0019] 2, the damping force generator 50 includes a main valve section 51 that mainly generates the damping force in the shock absorber 2 (see FIG. 1), and a damping force adjustment section 60 that adjusts the magnitude of the damping force generated by the damping force generator 50. Furthermore, the damping force generator 50 includes a connection flow path section 90 that forms a flow path for oil from the communication path L to the main valve section 51.

[0020] (Main valve section 51) The main valve section 51 has a main valve 52 that generates a damping force by controlling the flow of oil to throttle it, and a main valve seat 53 that faces the main valve 52 and comes into contact with it. The main valve section 51 also has an elastic member 54 that applies a force to press the main valve 52 against the main valve seat 53 by elastically deforming, and a seal member 55 that seals the gap between the main valve 52 and a guide member 61, which will be described later.

[0021] (Main Valve 52) The main valve 52 has a cylindrical portion 521 and a bottom portion 522 that covers a first-side opening of the cylindrical portion 521. The inner diameter of the cylindrical portion 521 is larger than the inner diameter of the main valve seat 53, and the outer diameter is smaller than the diameter of the inner circumferential surface of a guide member 61 (described later). The first-side end of the cylindrical portion 521 has an inner protrusion 523 that protrudes from the first-side end face toward the first side and is provided on the second inner side, and an outer protrusion 524 that is provided on the second outer side of the inner protrusion 523. The inner protrusion 523 and the outer protrusion 524 are each formed in an annular shape.

[0022] A groove 525 recessed from the outer circumferential surface toward the second inward direction is formed around the entire circumference of the cylindrical portion 521. The cross section of the groove 525 cut along a plane passing through the center line of the cylindrical portion 521 is rectangular. A seal member 55 is fitted into the groove 525. The diameter of the outer circumferential surface of the cylindrical portion 521 is formed to gradually or continuously decrease with increasing distance from the groove 525 in the second axial direction. Therefore, the gap between the cylindrical portion 521 and the inner circumferential surface of the guide member 61 is smallest on both sides of the groove 525 and gradually or continuously increases with increasing distance from the groove 525 in the second axial direction.

[0023] An introduction hole 526 is formed in the bottom portion 522 around the center line of the cylindrical portion 521. In the example shown in Fig. 3, two introduction holes 526 are formed. Also, as shown in Fig. 3, conical recesses may be formed on both sides of the introduction hole 526 in the second axial direction. When viewed in the second axial direction, the introduction holes 526 are formed so as not to overlap with a through hole 69 (described later) of the guide member 61.

[0024] (Main valve seat 53) The main valve seat 53 is a cylindrical member and has a flange portion 531 at the end on the first side that protrudes cylindrically from the outer circumferential surface all the way to the second outside. The flange portion 531 is a cylindrically protruding portion that sandwiches the guide member 61 and the like between it and the cap portion 80, which will be described later.

[0025] The main valve seat 53 has an inner seat portion 533 at the second end portion that protrudes from the second end face toward the second side, and an outer seat portion 534 that is provided on the second inner side and the second outer side of the inner seat portion 533. The inner seat portion 533 and the outer seat portion 534 are each formed in an annular shape. The inner seat portion 533 is provided at a position corresponding to the inner protrusion 523 of the main valve 52, and the outer seat portion 534 is provided at a position corresponding to the outer protrusion 524 of the main valve 52.

[0026] (Elastic member 54) As shown in FIG. 3 , the elastic member 54 is plate-shaped and has an annular portion 541 formed in an annular shape and a plurality of arm portions 542 protruding from the annular portion 541 toward the second inward direction. The annular portion 541 is set to have approximately the same size as the second-side end face of the cylindrical portion 521 of the main valve 52. The arm portions 542 are formed so that their circumferential size gradually decreases toward the second inward direction. The diameter of an imaginary circle formed by connecting the tip ends of the plurality of arm portions 542 is larger than the outer diameter of a first protrusion 662 (described later) of the guide member 61 and smaller than the outer diameter of the first surface 661.

[0027] The elastic member 54 is formed from metal or the like, and the distal ends of the multiple arms 542 are supported by the first surface 661. The annular portion 541 elastically deforms to move toward the second side in response to movement of the main valve 52 toward the second side, thereby applying a force in a direction returning the main valve 52 toward the main valve seat 53. The multiple arms 542 are desirably arranged so that the elastic member 54 has a point-symmetric or line-symmetric shape when viewed in the second axial direction. For example, as shown in FIG. 3 , an even number (e.g., six) of arms 542 are formed at equal intervals in the circumferential direction, thereby resulting in a point-symmetric or line-symmetric shape for the elastic member 54. The point-symmetric or line-symmetric shape of the elastic member 54 makes it easier to apply a uniform force to the main valve 52.

[0028] (Sealing member 55) The sealing member 55 is an annular member whose cross-sectional shape when cut along a plane parallel to the second axial direction is a rectangle whose longitudinal direction is the second axial direction and whose lateral direction is the second radial direction. However, the sealing member 55 has a joint 550 formed in a portion of its circumferential direction. The cross-sectional shape is not critical as long as the sealing member 55 functions as intended. FIG. 5 is a diagram showing the joint 550 separated to clarify the configuration of the joint 550. The joint 550 has a rectangular parallelepiped protruding portion 551 at one circumferential end that protrudes toward the other end, and a receiving portion 552 formed at the other end for receiving the protruding portion 551. The sealing member 55 is fitted into the groove 525 with the protruding portion 551 seated on the receiving portion 552.

[0029] The main valve 52 and main valve seat 53 configured as described above constitute a first valve mechanism V1 that opens and closes a first flow path R1 (see FIG. 7 ) through which oil flows from the communication path L to the reservoir chamber R through a horizontal hole 64 (described later) in the guide member 61. That is, the inner protrusion 523 and outer protrusion 524 of the main valve 52 close the first flow path R1 by contacting an inner seat portion 533 and an outer seat portion 534 of the main valve seat 53, respectively, and open the first flow path R1 by moving away from the inner seat portion 533 and the outer seat portion 534. The first valve then throttles the flow of oil in the first flow path R1, generating a damping force.

[0030] (Damping Force Adjustment Unit 60) As shown in Fig. 2, the damping force adjustment unit 60 includes a guide member 61 that guides movement of the main valve 52 in the second axial direction, and a control valve 70 that moves relative to the guide member 61 to open and close a second flow path R2 (see Fig. 6) that is formed in parallel with the first flow path R1. The damping force adjustment unit 60 also includes a pressing member 77 that presses the control valve 70 against the guide member 61, a coil spring 79 that is disposed between the control valve 70 and the pressing member 77, and a solenoid 100 that moves the pressing member 77 toward and away from the guide member 61. The damping force adjustment unit 60 also includes a restricting member 72 that restricts movement of the control valve 70 toward the second side, and a biasing member 75 that applies a force to the control valve 70 in a direction opposite to the thrust of a solenoid unit 102, which will be described later. The damping force adjuster 60 also has a first spacer member 73A interposed between the biasing member 75 and the restricting member 72, a second spacer member 73B interposed between the restricting member 72 and a cap portion 80 (described later), and a third spacer member 73C interposed between the guide member 61 and the biasing member 75. The damping force adjuster 60 also has a cap portion 80 that covers the peripheries of the control valve 70, the restricting member 72, the first spacer member 73A, the second spacer member 73B, and the third spacer member 73C.

[0031] (Guide member 61) The guide member 61 has a cylindrical portion 62 and a top portion 65 that covers a second opening of the cylindrical portion 62. The inner diameter of the cylindrical portion 62 is larger than the outer diameter of the cylindrical portion 521 of the main valve 52 and smaller than the outer diameter of the flange portion 531 of the main valve seat 53. The main valve 52 is disposed on the second inner side of the cylindrical portion 62. The outer diameter of the cylindrical portion 62 is smaller than the inner diameter of a first cylindrical portion 81 of the cap portion 80, which will be described later.

[0032] A step 63 recessed from the first end face to the second side is formed on the inner periphery of the cylindrical portion 62 at the end on the first side. The step 63 has a rectangular cross section taken along a plane passing through the center line of the cylindrical portion 62, and a flange portion 531 of the main valve seat 53 can be fitted into the step 63. A horizontal hole 64 is formed in the second radial direction in a portion of the cylindrical portion 62 on the second side of the step 63. The horizontal hole 64 is, for example, cylindrical, and multiple horizontal holes 64 are formed in the circumferential direction. Note that the horizontal hole 64 may be omitted by forming a gap when the step 63 and the flange portion 531 of the main valve seat 53 are fitted together, which communicates with a return hole 93 (described later).

[0033] The top portion 65 has a central portion 66 which is an inner peripheral side (second inner side), an outer peripheral portion 67 which is an outer peripheral side (second outer side), and an intermediate portion 68 between the central portion 66 and the outer peripheral portion 67. The central portion 66 protrudes more toward the main valve 52 than the outer peripheral portion 67, and the intermediate portion 68 is inclined in a planar or curved manner with respect to the second radial direction.

[0034] A through-hole 69 in the second axial direction is formed in the central portion 66. The through-hole 69 is composed of a first hole 691 formed on the first side and a second hole 692 formed on the second side. The through-hole 69 constitutes a part of the second flow path R2 branching off from the first flow path R1. The central portion 66 has a first protrusion 662 that protrudes cylindrically from a first surface 661, which is the end face of the first side, around the opening of the first hole 691 on the first side. The first surface 661 restricts movement of the elastic member 54 toward the second side. The first protrusion 662 is inserted into the second inner side of the elastic member 54, and the outer peripheral surface of the first protrusion 662 restricts movement of the elastic member 54 in the second radial direction.

[0035] Furthermore, the central portion 66 has a second protrusion 663 that protrudes conically from a second inner portion of the intermediate portion 68 toward the second side around the second opening of the second hole 692. The control valve 70 is able to come into contact with and separate from the second protrusion 663. Therefore, the control valve 70 closes the second flow path R2 when it comes into contact with the second protrusion 663, and opens the second flow path R2 when it moves away from the second protrusion 663. In other words, the control valve 70 and the second protrusion 663 constitute a second valve mechanism V2 that opens and closes the second flow path R2.

[0036] Because the central portion 66 protrudes more toward the main valve 52 than the outer peripheral portion 67 and the intermediate portion 68 is inclined with respect to the second radial direction, a recess 664 is formed around the second hole 692 that is recessed more toward the first side than the second-side end face of the outer peripheral portion 67. The recess 664 allows the biasing member 75 to deform and can accommodate the first-side portion of the control valve 70 even when the control valve 70 has moved most toward the first side and is in contact with the second protruding portion 663.

[0037] (Control Valve 70) The control valve 70 has a cylindrical portion 701 and a conical portion 702 that covers the opening on the first side of the cylindrical portion 701 and protrudes toward the first side. The control valve 70 also has a protruding portion 703 that protrudes around the entire circumference to the second outer side at the end of the cylindrical portion 701 on the first side. The control valve 70 also has a flat surface 704 that is perpendicular to the second axial direction at the end of the conical portion 702 on the second side, in a position on the second inner side. The control valve 70 also has a protruding portion 706 that protrudes to the second outer side at the center of the conical portion 702 in the second axial direction. The protruding portion 706 has a flat surface 707 that is perpendicular to the second axial direction.

[0038] The outer diameter of the cylindrical portion 701 is equal to or larger than the outer diameter of the flange portion 773 of the pressing member 77, and the inner diameter of the cylindrical portion 701 is smaller than the outer diameter of the flange portion 773. As a result, the second end surface of the cylindrical portion 701 comes into contact with the flange portion 773 of the pressing member 77.

[0039] Furthermore, the inner diameter of the cylindrical portion 701 is larger than the outer diameter of the cylindrical portion 771 of the pressing member 77. As a result, the cylindrical portion 771 and bottom portion 772 of the pressing member 77 are accommodated in the second inner portion of the control valve 70, with the second end surface of the cylindrical portion 701 in contact with the flange portion 773 of the pressing member 77. Then, a coil spring 79 is disposed inside a space 705 formed between the cylindrical portion 701 of the control valve 70 and the cylindrical portion 771 of the pressing member 77. A first end of the coil spring 79 is supported by a flat surface 704 of the control valve 70, and a second end of the coil spring 79 is supported by the flange portion 773 of the pressing member 77. In this way, the coil spring 79 is a member that acts at both ends and does not have a fixed end, so that part of the thrust of the solenoid portion 102 does not act on a fixed member beyond the fixed end via the fixed end. Therefore, the thrust of the solenoid portion 102 applied to the coil spring 79 is entirely used to deform the coil spring 79 itself, resulting in high thrust efficiency.

[0040] 3, the restricting member 72 has an annular portion 721 formed in an annular shape and a plurality of arm portions 722 protruding toward a second inner side from the annular portion 721. The diameter of an imaginary circle formed by the second inner tips of the plurality of arm portions 722 is larger than the diameter of the outer peripheral surface of the cylindrical portion 701 of the control valve 70 and smaller than the diameter of the outer peripheral surface of the protruding portion 703.

[0041] ((First spacer member 73A, second spacer member 73B, and third spacer member 73C)) The first spacer member 73A, second spacer member 73B, and third spacer member 73C are annular members. The outer diameters of the first spacer member 73A, second spacer member 73B, and third spacer member 73C are larger than the inner diameter of a second cylindrical portion 82 (described later) of the cap portion 80, but smaller than the inner diameter of a first cylindrical portion 81 (described later). Furthermore, the inner diameters of the first spacer member 73A, second spacer member 73B, and third spacer member 73C are larger than the inner diameter of the second cylindrical portion 82 of the cap portion 80, but smaller than the inner diameter of the first cylindrical portion 81.

[0042] The first spacer member 73A and the second spacer member 73B are disposed between the first end face of the second cylindrical portion 82 of the cap portion 80 and the biasing member 75, and determine the position of the restricting member 72 in the second axial direction. More specifically, the restricting member 72 is located on the second side of the protruding portion 703 of the control valve 70, and restricts the control valve 70 from moving toward the second side.

[0043] The position of the regulating member 72 in the second axial direction can be adjusted by adjusting the size (hereinafter sometimes referred to as "thickness") of the first spacer member 73A and the second spacer member 73B. For example, if it is desired to set the position of the regulating member 72 in the second axial direction to a first side relative to FIG. 4 , the thickness of the first spacer member 73A should be made thinner than the thickness shown in FIG. 4 , and the thickness of the second spacer member 73B should be made thicker than the thickness shown in FIG. 4 . On the other hand, if it is desired to set the position of the regulating member 72 in the second axial direction to a second side relative to FIG. 4 , the thickness of the first spacer member 73A should be made thicker than the thickness shown in FIG. 4 , and the thickness of the second spacer member 73B should be made thinner than the thickness shown in FIG. 4 .

[0044] The third spacer member 73C is disposed between the biasing member 75 and the guide member 61 and determines the position of the biasing member 75 in the second axial direction. The position of the biasing member 75 in the second axial direction can be adjusted by adjusting the size of the third spacer member 73C in the second axial direction (hereinafter, sometimes referred to as "thickness"). For example, if it is desired to set the position of the biasing member 75 in the second axial direction to a position closer to the first side than shown in FIG. 4 , the thickness of the third spacer member 73C should be made thinner than the thickness shown in FIG. 4 , and the thickness of the first spacer member 73A should be made thicker than the thickness shown in FIG. 4 . On the other hand, if it is desired to set the position of the biasing member 75 in the second axial direction to a position closer to the second side than shown in FIG. 4 , the thickness of the third spacer member 73C should be made thicker than the thickness shown in FIG. 4 , and the thickness of the first spacer member 73A should be made thinner than the thickness shown in FIG. 4 .

[0045] ((Biasing Member 75)) The biasing member 75 is an annular leaf spring that applies a force to the control valve 70 in a direction opposite to the thrust of the solenoid unit 102 and the spring force of the coil spring 79, and is set to have a spring constant higher than that of the coil spring 79. The biasing member 75 is formed in an annular shape and has an annular portion 751 that functions as a fixed end, and a plurality of arm portions 752 that protrude from the annular portion 751 toward the second inward direction and function as an acting end. Note that the shape of the biasing member 75 is not limited to this, and is not particularly limited as long as it has a fixed end and an acting end that acts on the control valve 70. For example, three of the multiple arm portions 752 are provided at equal intervals in the circumferential direction of the annular portion 751. However, the number of arm portions 752 is not limited to three, and may be two or less, four or more. Furthermore, the shapes of the multiple arm portions 752 may all be the same or different from each other. For example, the circumferential sizes of the multiple arm portions 752 may be different from each other. The biasing member 75 does not have to be a leaf spring, but may be an elastic member such as a coil spring interposed between the control valve 70 and the guide member 61 .

[0046] ((Pressing member 77)) As shown in Figure 4, the pressing member 77 has a cylindrical portion 771, a bottom portion 772 that covers the opening on the first side of the cylindrical portion 771, and a flange portion 773 that is provided at the end of the second side of the cylindrical portion 771 and protrudes outward along the entire circumference.

[0047] ((Coil spring 79)) The coil spring 79 is a compression coil spring that contacts the control valve 70 on a first side and contacts the pressing member 77 on a second side. The coil spring 79 applies forces to the pressing member 77 and the control valve 70 in directions that move the pressing member 77 and the control valve 70 away from each other. Note that instead of the coil spring 79, another member, such as an elastic ring, can be used as long as it exhibits the same function.

[0048] (Cap portion 80) The cap portion 80 has three cylindrical portions with the same outer diameter but different inner diameters, namely a first cylindrical portion 81 arranged on the first side, a second cylindrical portion 82 arranged on the second side from the first cylindrical portion 81, and a third cylindrical portion 83 arranged on the second side from the second cylindrical portion 82. The outer diameter of the cap portion 80 is smaller than the inner diameter of the inner housing 180 described below, and the cap portion 80 is arranged on the second inner side of the inner housing 180.

[0049] The inner diameter of the first cylindrical portion 81 is larger than the outer diameters of the guide member 61, the first spacer member 73A, the second spacer member 73B, the third spacer member 73C, the regulating member 72 and the urging member 75, and is positioned on the second outer side of these members.

[0050] The inner diameter of the second cylindrical portion 82 is smaller than the outer diameters of the guide member 61, the first spacer member 73A, the second spacer member 73B, the third spacer member 73C, the restricting member 72, and the biasing member 75. The guide member 61, the first spacer member 73A, the second spacer member 73B, the third spacer member 73C, the restricting member 72, and the biasing member 75 are sandwiched between the first end face of the second cylindrical portion 82 and the flange portion 531 of the main valve seat 53, and the positions of these members in the second axial direction are fixed.

[0051] The inner diameter of the third cylindrical portion 83 is larger than the outer diameter of the plunger 117, which will be described later, and smaller than the outer diameter of a flange portion 773 of the pressing member 77. This allows the first end of the plunger 117, the pressing member 77, the coil spring 79, and the control valve 70 to be housed inside the second interior of the cap portion 80. A groove portion 831 recessed from the end face toward the second side is formed in the first end of the third cylindrical portion 83.

[0052] A second axial groove 84, which is a groove recessed from the outer peripheral surface toward the second inner side, is formed in the outer peripheral portion of the cap portion 80 over the entire area in the second axial direction. One or more second axial grooves 84 are formed in the circumferential direction. In addition, a second radial groove 85, which is a groove recessed from the end face toward the first side, is formed over the entire area in the second radial direction at the end on the second side of the cap portion 80. The second radial groove 85 is formed in a position corresponding to the second axial groove 84, and discharges oil that has passed through the interior of the second inner side of the third cylindrical portion 83 into an annular gap S1, which will be described later.

[0053] (Solenoid 100) The solenoid 100 includes a valve portion 101 that opens and closes the second flow path R2, a solenoid portion 102 that drives a plunger 117 (described later) of the valve portion 101, and a housing 160 that accommodates the valve portion 101, a coil 121 (described later) of the solenoid portion 102, and the like. The solenoid 100 also includes an elastic seal member 190 that seals a gap between the solenoid portion 102 and the housing 160.

[0054] ((Valve section 101)) The valve section 101 has a fixed fixed section 110 and a movable section 116 that is movable relative to the fixed section 110. The fixed section 110 has a first fixed member 111 provided on a first side, a second fixed member 112 provided on a second side of the first fixed member 111, and a spacer 113 provided between the first fixed member 111 and the second fixed member 112. The first fixed member 111 and the second fixed member 112 are molded using a magnetic material such as iron, and the spacer 113 is molded using a non-magnetic material such as resin.

[0055] The first fixed member 111 has a first protrusion 111a that protrudes in an annular shape from the outer circumferential surface at the end on the first side toward the second outside. The first fixed member 111 has a first bearing 114 inside that supports a plunger 117 (described later) so that the plunger 117 can move in the second axial direction. The first bearing 114 is cylindrical and is fixed to the first fixed member 111 so that it cannot move.

[0056] The second fixed member 112 has a cylindrical portion 112a provided on the first side, and a cover portion 112b provided on the second side of the cylindrical portion 112a and covering the opening of the cylindrical portion 112a. An inner portion of the cover portion 112b has a second bearing 115 that supports a plunger 117 (described later) so that the plunger 117 can move in the second axial direction. The second bearing 115 is cylindrical and fixed to the second fixed member 112 so that it cannot move.

[0057] The movable part 116 has a cylindrical plunger 117 that holds the pressing member 77, and a movable iron core 118 that is held around the plunger 117. The plunger 117 is a rod-shaped member formed along the second axial direction. The plunger 117 holds the pressing member 77 on the first side and holds the movable iron core 118 in the axial center. The plunger 117 is supported by a first bearing 114 and a second bearing 115 so as to be movable in the second axial direction. When the solenoid part 102 is in an energized state, the plunger 117 is pushed out together with the pressing member 77 by the solenoid part 102 toward the first side. On the other hand, when the solenoid part 102 is in a de-energized state, the plunger 117 is pushed back together with the pressing member 77 toward the second side by the coil spring 79.

[0058] (Housing 160) The housing 160 includes a substantially cylindrical outer housing 170 provided on the outside, and an inner housing 180 provided inside the outer housing 170. The outer housing 170 and the inner housing 180 can be formed, for example, from metal. Alternatively, the outer housing 170 can be formed from metal, and the inner housing 180 can be formed from resin.

[0059] The outer housing 170 has a first cylindrical portion 171 provided on the first side and a second cylindrical portion 172 provided on the second side of the first cylindrical portion 171. The inner diameter of the first cylindrical portion 171 and the inner diameter of the second cylindrical portion 172 are the same. On the other hand, the outer diameter of the first cylindrical portion 171 is larger than the outer diameter of the second cylindrical portion 172. The end of the first cylindrical portion 171 on the second side has an inclined surface 173 that is inclined with respect to the axial direction so that the diameter gradually increases from the second side to the first side.

[0060] The first cylindrical portion 171 has a protrusion 174 at the end on the first side that protrudes in an annular shape from the inner circumferential surface toward the second inner side. The first cylindrical portion 171 has a groove 175 that is recessed from the outer circumferential surface 170a toward the second inner side along the entire circumference. The groove 175 has a first surface 176 that is inclined in the second axial direction, a second surface 177 that is a surface that forms an obtuse angle with the first surface 176, and a curved surface 178 formed between the first surface 176 and the second surface 177. The first surface 176 is formed closer to the first side than the second surface 177. In other words, the first surface 176 is located closer to the outside air than the second surface 177.

[0061] The second cylindrical portion 172 has a recess 172a recessed from the outer peripheral surface toward the second inside. The recess 172a is rectangular parallelepiped and formed in a portion of the circumferential direction. The outer housing 170 has a shape such that the first end surface of the first cylindrical portion 171, which is the first side portion, conforms to the outer peripheral surface of the damper case 13 of the cylinder portion 10, and the outer peripheral portion of the first cylindrical portion 171 is fixed to the damper case 13 by, for example, welding. A female thread 179 is formed on the inner peripheral surface of the outer housing 170. The outer peripheral surface 170a of the first cylindrical portion 171 is painted. For example, the paint may be cationic electrodeposition coating, which has high corrosion resistance.

[0062] The inner housing 180 has a cylindrical portion 181 having a substantially cylindrical shape and an annular portion 182 that protrudes from the inner circumferential surface of the cylindrical portion 181 toward a second inward direction. A male thread 183 is formed at the first end of the cylindrical portion 181, and is fastened to a female thread 179 formed on the inner circumferential surface of the outer housing 170. A recess 184 recessed from the outer circumferential surface is formed in the cylindrical portion 181 at a location on the second side of the male thread 183, and an O-ring 185 that seals between the outer circumferential surface of the inner housing 180 and the inner circumferential surface of the outer housing 170 is fitted into the recess 184. A first engagement portion 186 recessed from the inner circumferential surface is formed around the entire circumference of the cylindrical portion 181 at the second end.

[0063] ((Solenoid portion 102)) The solenoid portion 102 has a cover portion 120 that covers the opening of the housing 160, and a clip 103 that positions the cover portion 120 in the axial direction relative to the housing 160. When the solenoid portion 102 is energized, it pushes the plunger 117 toward the first side.

[0064] Clip 103 is a metal member whose cross-sectional shape when cut along a plane parallel to the second axial direction is a rectangle with the axial direction as the short side and the radial direction as the long side, and whose cross-sectional shape when cut along a plane perpendicular to the second axial direction is C-shaped.

[0065] The cover portion 120 includes a coil 121, a covering portion 130 that holds the coil 121 and covers the opening of the housing 160, a connector portion 122 for applying current to the coil 121, and a connecting portion 123 that connects the covering portion 130 and the connector portion 122. The cover portion 120 is molded by insert molding, in which, with the metal coil 121 and the surrounding portion 150 held in a mold, resin heated to a softening temperature is filled into the mold at portions corresponding to the covering portion 130, the connector portion 122, and the connecting portion 123. Therefore, the covering portion 130, the connector portion 122, and the connecting portion 123 are molded from molded resin. The connecting portion 123 protrudes outward in a rectangular parallelepiped shape from the outer periphery of the covering portion 130. The connector portion 122 is provided so as to protrude from a second outer end of the connecting portion 123 toward the first side.

[0066] The covering portion 130 has a disk-shaped portion 131 that covers the opening of the housing 160, a surrounding portion 132 that protrudes from the disk-shaped portion 131 to the first side and covers the periphery of the coil 121, and an surrounding portion 150 that surrounds the periphery of the second outer side of the housing 160.

[0067] A recess 140 recessed from the end face on the first side is formed on the outer periphery of the disk-shaped portion 131. The recess 140 is formed by a parallel surface 141 parallel to the second axial direction, an orthogonal surface 142 formed at the end of the second side and orthogonal to the second axial direction, and a recess 143 recessed from the parallel surface 141 toward the second inside.

[0068] The peripheral portion 132 is cylindrical and is provided outside the second fixing member 112 and inside the housing 160. The peripheral portion 132 has the coil 121 at a position overlapping the movement area of ​​the movable iron core 118 fixed to the plunger 117 in the second axial direction. The peripheral portion 132 also has a second engagement portion 135 recessed from the outer circumferential surface formed around the entire circumference at a location on the second side of the center in the second axial direction. The second engagement portion 135 is formed at a position in the axial direction corresponding to the first engagement portion 186 formed on the cylindrical portion 181 of the inner housing 180. A clip 103 is fitted into the second engagement portion 135 and the first engagement portion 186.

[0069] The enclosure 150 has a cylindrical first cylindrical portion 151 disposed on the first side, a cylindrical second cylindrical portion 152 disposed on the second side, and a connecting portion 153 connecting the first cylindrical portion 151 and the second cylindrical portion 152. The inner diameter of the first cylindrical portion 151 is larger than the outer diameter of the first cylindrical portion 171 of the outer housing 170. The inner diameter of the second cylindrical portion 152 is larger than the outer diameter of the second cylindrical portion 172 of the outer housing 170 but smaller than the outer diameter of the first cylindrical portion 171. The connecting portion 153 is inclined with respect to the axial direction so that the diameter of its inner surface gradually increases from the second side to the first side. The connecting portion 153 is disposed so as to face the inclined surface 173 of the first cylindrical portion 171.

[0070] A first protrusion 155 protruding from the inner circumferential surface toward the second inner side is provided at the first end of the second cylindrical portion 152. The first protrusion 155 is rectangular parallelepiped and is formed on a portion of the circumferential direction. The circumferential position of the cover portion 120 relative to the outer housing 170 is determined by fitting the first protrusion 155 into a recess 172a formed in the outer housing 170. In addition, a second protrusion 156 protruding from the inner circumferential surface toward the second inner side is provided at the second end of the second cylindrical portion 152.

[0071] The enclosure 150 may be formed, for example, from a metal material such as iron, stainless steel, aluminum, or brass. The enclosure 150 is held in the disk-shaped portion 131 by fitting the second protrusion 156 into the recess 143 of the disk-shaped portion 131. While the enclosure 150 and the cover 130 are integrated by insert molding as described above, the enclosure 150 may be fitted into the recess 143 of the cover 130 that has already been molded. When fitting the second protrusion 156 into the recess 143, the second end of the enclosure 150 may be elastically deformed to expand. This allows the disk-shaped portion 131 and the enclosure 150 to be firmly integrated before assembly to the outer housing 170. The disk-shaped portion 131 and the enclosure 150 may be connected by other methods, such as adhesive or welding. The surrounding portion 150 is painted. The painting may be, for example, cationic electrodeposition painting, which has high corrosion resistance.

[0072] The seal member 190 can be, for example, an O-ring molded from a rubber-based material. The inner diameter of the seal member 190 is smaller than the outer diameter of the first cylindrical portion 171 of the outer housing 170. The outer diameter of the seal member 190 is larger than the inner diameter of the first cylindrical portion 151 of the enclosure 150. When the cover portion 120 is attached to the outside of the outer housing 170 of the housing 160, the seal member 190 is sandwiched between the enclosure 150 and the outer housing 170 and comes into contact with the inner circumferential surface, the first surface 176, and the second surface 177 of the first cylindrical portion 151 of the enclosure 150.

[0073] (Connection Flow Path Portion 90) As shown in FIG. 2 , the connection flow path portion 90 has a cylindrical portion 91 and a flange portion 92 that cylindrically protrudes from the outer peripheral surface of the cylindrical portion 91 to the second outer side around the entire circumference at the second end of the cylindrical portion 91. The outer diameter of the cylindrical portion 91 is smaller than the inner diameter of the protruding portion 174 of the outer housing 170, and the inner diameter of the cylindrical portion 91 is smaller than the inner diameter of the main valve seat 53. The outer diameter of the flange portion 92 is larger than the inner diameter of the protruding portion 174 of the outer housing 170 and smaller than the inner diameter of the first cylindrical portion 171. The flange portion 92 is disposed on the second side of the protruding portion 174 of the outer housing 170. A return flow hole 93 is formed in the flange portion 92 in the second axial direction. A plurality of return flow holes 93 are formed in the circumferential direction.

[0074] The second inner side of the cylindrical portion 91 communicates with the outer cylinder opening 12H on the first side and communicates with the second inner side of the main valve seat 53 on the second side. The second inner side of the cylindrical portion 91 constitutes a part of the first flow path R1. The return hole 93 communicates with the case opening 13H on the first side and communicates with the annular gap S1 on the second side.

[0075] The damping force generator 50 configured as described above can be assembled, for example, using the assembly method described below. That is, an operator assembles the connection flow path portion 90, main valve seat 53, main valve 52, elastic member 54, guide member 61, biasing member 75, regulating member 72, first spacer member 73A, second spacer member 73B, third spacer member 73C, cap portion 80, and first fixing member 111 inside the outer housing 170 fixed to the outer peripheral surface of the damper case 13, and then tightens the inner housing 180 to the outer housing 170. In addition, the operator positions the control valve 70 so that the protruding portion 703 and the convex portion 706 of the control valve 70 are positioned between the biasing member 75 and the regulating member 72, and positions the coil spring 79 on the second inner side of the control valve 70. Furthermore, the pressing member 77 held by the plunger 117 is positioned so that the cylindrical portion 701 of the pressing member 77 is located on the second inner side of the coil spring 79 and the flange portion 773 is located on the second side of the coil spring 79. Then, the spacer 113 and the second fixing member 112 are inserted on the second side of the first fixing member 111, and the solenoid portion 102 is assembled. Before assembling the solenoid portion 102, the seal member 190 is fitted into the groove 175 of the outer housing 170.

[0076] In the damping force generator 50 configured as described above, an annular gap S1 is formed between the inner circumferential surface of the first cylindrical portion 171 of the outer housing 170 and the outer circumferential surface of the cylindrical portion 62 of the guide member 61. In addition, as shown in Fig. 7 and other figures, a first flow path R1 is formed through which oil flows to the reservoir chamber R through the communication path L, the second inside of the cylindrical portion 91 of the connection flow path portion 90, between the main valve 52 and the main valve seat 53, the horizontal hole 64 of the guide member 61, the annular gap S1, and the return hole 93 of the flange portion 92 of the connection flow path portion 90. As shown in FIG. 7 and other figures, a second flow path R2 is formed, branching from the first flow path R1 upstream of the main valve 52, passing through the inlet hole 526 in the bottom 522 of the main valve 52, the through hole 69 in the top 65 of the guide member 61, the second inner side of the third cylindrical portion 83 of the cap portion 80, the second radial groove 85, and the second axial groove 84, and reaching the annular gap S1 to merge with the first flow path R1.

[0077] Furthermore, the outer peripheral surface of the cylindrical portion 521 of the main valve 52 and the inner peripheral surface of the cylindrical portion 62 of the guide member 61 are sealed by a seal member 55. In other words, a seal mechanism 56 that seals between the outer peripheral surface of the cylindrical portion 521 of the main valve 52 and the inner peripheral surface of the cylindrical portion 62 of the guide member 61 is formed by the seal member 55 and a groove 525 formed in the outer peripheral surface of the cylindrical portion 521 of the main valve 52. Therefore, the guide member 61 forms a back pressure chamber 61P, located inside the guide member 61 and on the second side of the main valve 52, that applies oil pressure (hereinafter sometimes referred to as "back pressure") from the second side opposite the main valve seat 53 to the main valve 52.

[0078] [Adjustment Operation of Damping Force Adjustment Unit 60] Next, a description will be given of the adjustment operation of the damping force adjustment unit 60. By pressing the pressing member 77 toward the first side, the control valve 70 is pressed against the second protrusion 663 of the guide member 61. The pressing force of the pressing member 77, in other words, the thrust of the solenoid unit 102 (see FIG. 2), changes depending on the amount of current flowing through the solenoid unit 102.

[0079] For example, the damping force adjuster 60 is set to the state where the pressing force of the pressing member 77 is maximized. At this time, the control valve 70 is most strongly pressed against the second protrusion 663 of the guide member 61, and the second flow path R2 is closed.

[0080] Also, for example, in the damping force adjusting unit 60, a state is created in which the pressing force of the pressing member 77 is minimized. At this time, in the damping force adjusting unit 60, the control valve 70 moves away from the second protruding portion 663 of the guide member 61, and the second flow path R2 is opened.

[0081] Furthermore, for example, the damping force adjustment unit 60 is set to a state between the state where the pressing force of the pressing member 77 is greatest and the state where it is greatest. In this state, the damping force adjustment unit 60 has the control valve 70 move farther away from the second protrusion 663 of the guide member 61 than when the pressing force is greatest, and move closer to the second protrusion 663 than when the pressing force is greatest.

[0082] [Operation of Shock Absorber 2] First, the operation of the shock absorber 2 during the extension stroke will be described. During the extension stroke, the rod 20 moves to the other side (see FIG. 2) relative to the cylinder 11. At this time, the piston valve 32 remains blocking the piston oil passage port 311. Furthermore, as the piston portion 30 moves to the other side, the volume of the second oil chamber Y2 decreases. Then, the oil in the second oil chamber Y2 flows out from the communication hole 11H into the communication passage L.

[0083] The oil then flows through the communication passage L and the outer cylinder opening 12H into the damping force generator 50. In the damping force generator 50, the oil first flows into the second inner side of the cylindrical portion 91 of the connecting flow passage portion 90. Then, in the damping force generator 50, a damping force is generated in the main valve 52 or the control valve 70. The flow of oil at this time will be described in detail later.

[0084] The oil that has flowed into the main valve 52 or the control valve 70 then flows out into the annular gap S1. The oil then passes through the return hole 93 in the flange portion 92 of the connecting flow path portion 90 and flows from the case opening 13H into the reservoir chamber R. The pressure in the first oil chamber Y1 becomes lower than that of the reservoir chamber R. Therefore, the oil in the reservoir chamber R flows into the first oil chamber Y1 through the bottom portion 40.

[0085] Next, the operation of the shock absorber 2 during the compression stroke will be described. During the compression stroke, the rod 20 moves relative to one side (see FIG. 2 ) with respect to the cylinder 11. In the piston portion 30, the piston valve 32 that closes the piston oil passage port 311 opens due to the pressure difference between the first oil chamber Y1 and the second oil chamber Y2. Then, the oil in the first oil chamber Y1 flows out through the piston oil passage port 311 to the second oil chamber Y2. Here, the rod 20 is disposed in the second oil chamber Y2. Therefore, the oil flowing from the first oil chamber Y1 to the second oil chamber Y2 is in excess by the volume of the rod 20. Therefore, an amount of oil equivalent to the volume of this rod 20 flows out from the communication hole 11H to the communication passage L.

[0086] Furthermore, the oil flows into the damping force generator 50 through the communication path L and the outer cylinder opening 12H. The flow of oil in the damping force generator 50 is the same as the flow of oil during the extension stroke described above. That is, in the shock absorber 2 of the first embodiment, the direction of oil flow in the damping force generator 50 is the same during both the compression stroke and the extension stroke.

[0087] As described above, in the shock absorber 2, the damping force is generated by the damping force generator 50 during both the compression stroke and the extension stroke. The generation of the damping force by the damping force generator 50 will be described in detail below.

[0088] (Normal Operation) The flow of oil during normal operation when the solenoid portion 102 is energized and the pressing force of the pressing member 77 acts will be described.

[0089] ((Low Speed)) FIG. 6 is a diagram showing an example of oil flow when the piston portion 30 (see FIG. 1) is moving at a low speed with the pressing force of the pressing member 77 at its smallest. As shown in FIG. 6, when the piston portion 30 is moving at a low speed, the oil that has flowed into the second inner side of the cylindrical portion 91 of the connecting flow path portion 90 flows into the second inner side of the main valve seat 53. Here, because the moving speed of the piston portion 30 is low, no oil flow that opens the main valve 52 occurs in the first flow path R1 (see FIG. 7). Meanwhile, the oil that has flowed into the second inner side of the main valve seat 53 flows through the second flow path R2 as shown by the arrows in FIG. 6. The oil then flows out of the annular gap S1 into the reservoir chamber R. As described above, when the moving speed of the piston portion 30 is low, a damping force is generated by the flow of oil being throttled by the gap between the control valve 70 and the second protrusion 663 of the guide member 61.

[0090] ((High Speed)) FIG. 7 is a diagram showing an example of oil flow when the piston portion 30 (see FIG. 1) is moving at a high speed with the pressing force of the pressing member 77 at its smallest. As shown in FIG. 7 , when the piston portion 30 is moving at a high speed, the oil that has flowed into the second inner side of the cylindrical portion 91 of the connecting flow path portion 90 flows into the second inner side of the main valve seat 53. The oil that has flowed into the second inner side of the main valve seat 53 opens the main valve 52 and flows out into the reservoir chamber R. Note that even when the moving speed is high, the oil that has flowed into the second inner side of the main valve seat 53 is throttled by the gap between the control valve 70 and the second protruding portion 663 of the guide member 61, generating a pressure difference, and flows to the annular gap S1 and then into the reservoir chamber R, just as when the moving speed is low.

[0091] As described above, when the moving speed of the piston portion 30 is high, the damping force is generated mainly by the flow of oil in the first flow path R1 that passes between the main valve 52 and the main valve seat 53 .

[0092] Furthermore, the oil that has flowed into the second inner side of the main valve seat 53 transmits pressure to the back pressure chamber 61P through the inlet hole 526 in the bottom portion 522 of the main valve 52. However, the second flow path R2 that communicates with the back pressure chamber 61P is opened by the control valve 70. Therefore, the pressure in the back pressure chamber 61P is lower than when the control valve 70 is pressed against the second protrusion 663 of the guide member 61. The main valve 52, which receives pressure from the back pressure chamber 61P, is more likely to open the first flow path R1. Therefore, when the pressing force of the pressing member 77 is at its weakest, the damping force generated by the flow of oil in the first flow path R1 that opens the main valve 52 is lower than when the pressing force of the pressing member 77 is at its strongest.

[0093] ((Low Speed)) FIG. 8 is a diagram showing an example of oil flow when the piston portion 30 (see FIG. 1) is moving at a low speed with the pressing force of the pressing member 77 at its largest. As shown in FIG. 8, when the piston portion 30 is moving at a low speed, the oil that has flowed into the second inner side of the cylindrical portion 91 of the connection flow path 90 flows into the second inner side of the main valve seat 53. Here, because the movement speed of the piston portion 30 is low, no oil flows through the first flow path R1 (see FIG. 9) by opening the main valve 52. Meanwhile, the oil that has flowed into the second inner side of the cylindrical portion 91 of the connection flow path 90 flows through the second flow path R2 that passes through the inlet hole 526 in the bottom portion 522 of the main valve 52, as shown by the arrow in FIG. 8. The oil then flows out of the annular gap S1 into the reservoir chamber R.

[0094] As described above, when the moving speed of the piston portion 30 is low, the damping force is generated by the oil flowing through the second flow path R2 while opening the control valve 70. The damping force generated when the oil flows through the second flow path R2 is higher than when the control valve 70 is farther away from the second protrusion 663 of the guide member 61.

[0095] ((High Speed)) FIG. 9 is a diagram showing an example of oil flow when the moving speed of the piston portion 30 (see FIG. 1 ) is high and the pressing force of the pressing member 77 is at its largest. As shown in FIG. 9 , when the moving speed of the piston portion 30 is high, the oil that has flowed into the second inner side of the cylindrical portion 91 of the connecting flow path 90 flows into the second inner side of the main valve seat 53. The oil that has flowed into the second inner side of the main valve seat 53 opens the main valve 52 and flows out into the reservoir chamber R. Note that even when the moving speed is high, the oil that has flowed into the second inner side of the cylindrical portion 91 of the connecting flow path 90 is throttled by the gap between the second protrusion 663 of the guide member 61 and the control valve 70, generating a pressure difference, and flows to the annular gap S1 and further flows out into the reservoir chamber R, just as when the pressing force of the pressing member 77 is at its smallest. As described above, when the moving speed of the piston portion 30 is high, the damping force is generated mainly by the flow of oil in the first flow path R1 that passes between the main valve 52 and the main valve seat 53 .

[0096] Furthermore, the oil that has flowed into the second inner side of the cylindrical portion 91 of the connecting flow path 90 transmits pressure to the back pressure chamber 61P through the inlet hole 526 in the bottom portion 522 of the main valve 52. The second flow path R2, which communicates with the back pressure chamber 61P, is in a state in which the control valve 70 is pressed by the second protrusion 663 of the guide member 61. Therefore, the pressure in the back pressure chamber 61P is higher than when the second flow path R2 is open, as shown in FIG. 7 . The main valve 52, which is subjected to a force from the oil in the back pressure chamber 61P, has difficulty opening the first flow path R1. Therefore, when the pressing force of the pressing member 77 is at its strongest, the damping force generated by the flow of oil in the first flow path R1, which opens the main valve 52, is higher than when the pressing force of the pressing member 77 is at its weakest.

[0097] As described above, the shock absorber 2 adjusts the damping force both at low speeds and at high speeds by operating the pressing member 77. That is, the shock absorber 2 adjusts the flow path area of ​​the second flow path R2, which is the oil flow path at low speeds, and the flow path area of ​​the second flow path R2, which adjusts the pressure of the back pressure chamber 61P, which is related to the oil flow path area at high speeds, by changing the pressing force of the control valve 70 against the second protrusion 663 of the guide member 61 using the pressing member 77.

[0098] In the above-described operation example, two patterns, namely, the smallest and largest pressing force of the pressing member 77, have been described, but the present invention is not limited to these two patterns. The pressing force of the pressing member 77 can be set arbitrarily within an adjustable range according to the amount of current to the solenoid unit 102, in other words, the thrust of the solenoid unit 102. In accordance with this setting, the damping force adjustment unit 60 can adjust the damping force at low speeds and the damping force at high speeds in multiple stages.

[0099] (In an Abnormal State) Next, the flow of oil in an abnormal state in which the solenoid portion 102 is in a non-energized state and the pressing force of the pressing member 77 does not act will be described. An example of a case in which the solenoid portion 102 is in a non-energized state is when the current supply to the coil of the solenoid portion 102 is stopped, for example, due to a disconnection. Figure 10 is a diagram showing an example of the flow of oil when the solenoid portion 102 is in a non-energized state and the movement speed of the piston portion 30 (see Figure 1) is low. Figure 11 is a diagram showing an example of the flow of oil when the solenoid portion 102 is in a non-energized state and the movement speed of the piston portion 30 is high.

[0100] 10 and 11 , when the solenoid portion 102 is in a non-energized state, the plunger 117 is pushed back to the second side by the coil spring 79. Accordingly, the pressing member 77 fixed to the plunger 117 is pressed against the cap portion 80.

[0101] 10 , when the moving speed of the piston portion 30 is low, the oil that has flowed into the second inner side of the cylindrical portion 91 of the connecting flow path portion 90 flows through the second flow path R2 and flows out from the annular gap S1 into the reservoir chamber R. When the moving speed of the piston portion 30 is low, the damping force is generated by the flow of oil in the gap formed between the flange portion 773 of the pressing member 77 and the cap portion 80, i.e., in the groove portion 831.

[0102] ((At High Speed)) As shown in FIG. 11 , when the moving speed of the piston portion 30 is high, the oil that has flowed into the second inner side of the cylindrical portion 91 of the connecting flow path portion 90 opens the main valve 52 and flows out into the reservoir chamber R. Note that even when the moving speed is high, the oil that has flowed into the second inner side of the cylindrical portion 91 of the connecting flow path portion 90 flows to the annular gap S1 while generating a pressure difference due to the flow rate being restricted by the groove portion 831 formed in the cap portion 80, just as when the moving speed is low, and then flows out into the reservoir chamber R. As described above, when the moving speed of the piston portion 30 is high, the damping force is generated mainly by the flow of oil in the first flow path R1.

[0103] The oil flowing into the second inner side of the cylindrical portion 91 of the connecting flow passage 90 transmits pressure to the back pressure chamber 61P through the inlet hole 526 in the bottom portion 522 of the main valve 52. The back pressure chamber 61P is connected to the annular gap S1 via the second flow passage R2. The oil flow between the back pressure chamber 61P and the annular gap S1 must pass through the groove 831 formed in the cap portion 80. The groove 831 formed in the cap portion 80 restricts the oil flow, thereby suppressing the outflow of oil from the back pressure chamber 61P and maintaining the pressure in the back pressure chamber 61P at a level higher than the minimum pressing force of the pressing member 77 shown in FIG. 7 . The main valve 52, which receives force from the oil in the back pressure chamber 61P, has a relatively low tendency to open the first flow passage R1. Therefore, when the solenoid portion 102 is de-energized, the damping force generated by the oil flowing through the first flow passage R1, which opens the main valve 52, is relatively high.

[0104] As described above, in the shock absorber 2 of the first embodiment, even in an abnormal state in which the solenoid section 102 is not energized, both the damping force at low speeds and the damping force at high speeds are made relatively high.

[0105] (Difference between normal and abnormal conditions) When the resultant force of the force of the oil passing through the through hole 69 of the guide member 61 moving the control valve 70 to the second side and the force of the coil spring 79 exceeds the pressing force of the pressing member 77, the control valve 70 moves to the second side even if thrust is being generated by the solenoid unit 102. In particular, when the thrust of the solenoid unit 102 is relatively small, such as when the pressing force of the pressing member 77 is at its smallest as shown in Figures 6 and 7, if the pressure of the oil passing through the through hole 69 of the guide member 61 increases, the control valve 70 will temporarily move to the second side.

[0106] In the damping force generating device 50, even if the control valve 70 moves to the second side, the restricting member 72 restricts the movement of the control valve 70 to the second side. In other words, the protrusion 703 of the control valve 70 comes into contact with the restricting member 72, and the control valve 70 receives a force from the restricting member 72 in the direction of the first side, thereby restricting the movement of the control valve 70 to the second side.

[0107] Furthermore, the cylindrical portion 771 and bottom portion 772 of the pressing member 77 are disposed on the second inner side of the cylindrical portion 701 and conical portion 702 of the control valve 70, and the diameter of the outer periphery of the flange portion 773 of the pressing member 77 is equal to or smaller than the outer diameter of the cylindrical portion 701 of the control valve 70. Therefore, the pressing member 77 is less likely to be subjected to the force of the oil flowing through the through hole 69 of the guide member 61 toward the third cylindrical portion 83 of the cap portion 80. As a result, the pressing member 77 is also prevented from moving toward the second side, so that the pressing member 77 is more likely to remain in a stable normal operating position and is less likely to be pressed against the cap portion 80, which is the abnormal operating position.

[0108] As described above, in the damping force generator 50 according to this embodiment, even if the combined force of the oil force moving the control valve 70 to the second side and the force of the coil spring 79 exceeds the thrust of the solenoid unit 102 during normal operation, the pressing member 77 is unlikely to be pressed against the cap unit 80. That is, in the damping force generator 50, unlike in an abnormal operation, the pressing member 77 is unlikely to be pressed against the cap unit 80 during normal operation. As a result, the damping force generator 50 can prevent abnormal operation even when the mechanism is capable of normal operation, and can perform the abnormal operation when an abnormality occurs in the mechanism. Furthermore, even if the flow path cross-sectional area of ​​the groove 831 formed in the cap unit 80 is changed to adjust the damping force generated during an abnormal operation, this change can be prevented from affecting the damping force during normal operation.

[0109] As described above, the damping force generator 50 is an example of a damping force control valve including a structural member (e.g., the guide member 61) having a through hole 69 penetrating in the second axial direction. The damping force generator 50 also includes a control valve 70 (an example of a first valve body) that is provided opposite a second-side opening (an example of one opening) of the through hole 69 in the second axial direction and whose distance from the second-side opening of the through hole 69 is adjustable by a solenoid unit 102 (an example of an actuator). The damping force generator 50 also includes a back pressure chamber 61P whose internal pressure is adjusted by the second axial position of the control valve 70. The damping force generator 50 also includes a main valve 52 (an example of a second valve body) that is pressured in a valve-closing direction by the internal pressure, has an introduction hole 526 (an example of a communication hole) that communicates with the back pressure chamber 61P at a position offset from the central axis of the first-side opening (an example of the other opening) of the through hole 69, and is guided by the guide member 61 to move in the second axial direction. The damping force generating device 50 also has a main valve seat 53 (an example of a valve seat) on which the main valve 52 can be seated.

[0110] According to the damping force generating device 50 configured as described above, the area of ​​the inlet hole 526 formed in the main valve 52 does not overlap with the area of ​​the through-hole 69 formed in the control valve 70, and therefore it is possible to prevent the control valve 70 from opening unintentionally due to the influence of the dynamic pressure of oil that has passed through the inlet hole 526. Therefore, the opening and closing of the control valve 70 can be controlled with high accuracy, and the damping force can be adjusted with high accuracy.

[0111] The main valve 52 is provided with multiple inlet holes 526, and the multiple inlet holes 526 are positioned around the central axis. In other words, the main valve 52 has multiple inlet holes 526 formed around the center line of the through-hole 69 formed in the guide member 61. Therefore, compared to a case where only one inlet hole 526 is formed, the dynamic pressure acting on the main valve 52 due to oil entering the second inner side of the main valve seat 53 from the communication passage L is less likely to be concentrated in one location. As a result, tilt of the main valve 52 with respect to the second axial direction can be suppressed. In other words, tilt of the center line of the cylindrical portion 521 of the main valve 52 with respect to the center line of the cylindrical portion 62 of the guide member 61 can be suppressed. Alternatively, the inlet hole 526 may be formed at an angle.

[0112] 12 is an enlarged view showing an example of the configuration of the main valve 52, guide member 61, and seal mechanism 56. The damping force generator 50 also includes a seal mechanism 56 at a portion of the main valve 52 that always faces the guide member 61, and the outer diameter of the main valve 52 smoothly decreases with increasing distance from the seal mechanism 56 in the second axial direction. In other words, the gap between the portion of the main valve 52 facing the cylindrical portion 62 of the guide member 61 and the cylindrical portion 62 of the guide member 61 increases with increasing distance from the seal mechanism 56 in the second axial direction. Therefore, even if the main valve 52 tilts in the second axial direction due to dynamic pressure or the like, contact between the main valve 52 and the cylindrical portion 62 of the guide member 61 at their corners is suppressed, allowing the main valve 52 to move smoothly in the second axial direction.

[0113] Here, the sealing mechanism 56 is composed of a groove 525 (an example of an annular groove) formed on the outer periphery of the main valve 52, and a sealing member 55 provided in the groove 525. The groove 525 and / or the sealing member 55 are formed with a third flow path R3 (an example of a passage) that introduces the pressure of the back pressure chamber 61P into a pressure chamber 57 (an example of a pressing chamber) that generates a force that urges the sealing member 55 against the guide member 61. This allows for a highly reliable seal between the main valve 52 and the cylindrical portion 62 of the guide member 61, thereby enabling the damping force to be adjusted with high accuracy.

[0114] The structural member having a through hole 69 penetrating in the second axial direction is formed in a cylindrical shape with a bottom, and also serves as the guide member 61. In this way, the portion that guides the movement of the main valve 52 and the portion on which the control valve 70 is seated are integrally configured, making it possible to generate and adjust the damping force with a simple configuration.

[0115] The shock absorber 2 also includes a cylinder 11 filled with fluid, a piston portion 30 (an example of a piston) slidably fitted within the cylinder 11, and a rod 20 (an example of a piston rod) connected to the piston portion 30 and extending to the outside of the cylinder 11. The shock absorber 2 is also an example of a damping force adjustable shock absorber having a damping force generator 50 that generates a damping force by controlling the flow of fluid generated by the sliding of the piston portion 30 within the cylinder 11. With the shock absorber 2 configured as described above, the opening and closing of the control valve 70 can be controlled with high accuracy, and therefore the damping force can be adjusted with high accuracy.

[0116] 1...suspension device, 2...shock absorber, 10...cylinder portion, 11...cylinder, 20...rod, 30...piston portion, 50...damping force generating device, 51...main valve portion, 52...main valve (an example of a second valve body), 53...main valve seat (an example of a valve seat), 54...elastic member, 55...seal member (an example of a sealing mechanism), 57...pressure chamber, 60...damping force adjusting portion, 61...guide member (an example of a structural member), 61P...back pressure chamber, 62...cylindrical portion (an example of a tubular portion), 65...top portion (an example of a cover portion), 66...central portion (an example of a restricting portion), 67...outer periphery, 69...through hole, 70...control valve (an example of a first valve body), 525...groove (an example of a sealing mechanism), 526...introduction hole (an example of a communicating hole), 550...abutment, 663...second protrusion, 664...recess, R1...first flow path, R2...second flow path, R3...third flow path

Claims

1. A damping force control valve comprising: a structural member having a through hole formed therein that penetrates in the axial direction; a first valve body provided axially opposite one opening of the through hole and a distance from the one opening capable of being adjusted by an actuator; a back pressure chamber whose internal pressure is adjusted by the axial position of the first valve body; a second valve body that is pressured in a valve closing direction by the internal pressure, has a communication hole that communicates with the back pressure chamber at a position offset from the central axis of the other opening of the through hole, and moves in the axial direction while being guided by a guide member; and a valve seat on which the second valve body can be seated.

2. The damping force control valve according to claim 1, wherein a plurality of said communication holes are provided, the plurality of said communication holes being provided at positions centered around said central axis.

3. A damping force control valve as set forth in claim 1, wherein a sealing mechanism is provided at a portion of said second valve body that always faces said guide member, and the outer diameter smoothly decreases with increasing axial distance from said sealing mechanism.

4. A damping force control valve as described in claim 3, wherein the sealing mechanism is composed of an annular groove formed on the outer periphery of the second valve body and a sealing member provided in the annular groove, and the annular groove and / or the sealing member have a passage formed therein for introducing pressure from the back pressure chamber into a pressing chamber which generates a force for urging the sealing member against the guide member.

5. A damping force control valve as set forth in claim 3, wherein the structural member is formed in a cylindrical shape with a bottom and also serves as the guide member.

6. A damping force adjustable shock absorber having: a cylinder filled with fluid, a piston slidably fitted within the cylinder, a piston rod connected to the piston and extending to the outside of the cylinder, and a damping force adjustment valve for controlling the flow of fluid generated by the sliding of the piston within the cylinder to generate a damping force, wherein the damping force adjustment valve has: a bottomed cylindrical structural member having a through hole formed in the bottom thereof penetrating in the axial direction, a first valve body the distance to one opening of the through hole can be adjusted by an actuator, a back pressure chamber the internal pressure of which is adjusted by the axial position of the first valve body, a second valve body which is pressured in a valve closing direction by the internal pressure, has a communication hole communicating with the back pressure chamber at a position offset from the central axis of the through hole, and moves in the axial direction while being guided by the cylindrical portion of the structural member, and a valve seat on which the second valve body can be seated.

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