Abstract: Provided is a shock absorber that includes a middle chamber formed by a piston, a first damping-force generating device that is provided between an upper chamber and the middle chamber and generates a damping force, a second damping-force generating device that is provided between a lower chamber and the middle chamber and generates a damping force, and a position-based state changing device that changes a state of a passage to a state in which the upper chamber and the lower chamber communicate with each other, a state in which the upper chamber and the middle chamber communicate with each other, or a state in which the lower chamber and the middle chamber communicate with each other depending on a position of the piston.

Abstract: A tube having sealing ring grooves formed by a sequential rotational process and a shock absorber including the tube, in which durability of a sealing ring fitted in each of the sealing ring grooves is enhanced. An inclination angle (?1) formed with respect to a plane (PL1) perpendicular to an axis of a separator tube by a side surface of the sealing ring groove, which is located on an opening end side of the separator tube, is set to 8° or more. With this, a maximum tensile stress to be applied to an O-ring can be reduced to be smaller than a maximum tensile stress in a case of using a backup ring. As a result, the durability of the O-ring can be set equivalent to or enhanced to be higher than durability in the case of using the backup ring.

Abstract: A damping force is generated by controlling a flow of oil caused by a sliding displacement of a piston in a cylinder with the aid of a disk valve, against extension and compression of a piston rod. An elastic seal member, fixedly attached to a back surface side of the disk valve, is fitted in a recessed portion of a pilot body, by which a pilot chamber is formed and valve opening of the disk valve is controlled by inner pressure in the pilot chamber. The elastic seal member is in abutment with a bottom portion of the recessed portion, and the disk valve is urged toward inner and other seat portions by elasticity of the elastic seal member. This configuration ensures that the disk valve can be closed without a set load provided from deflection of the disk valve, thereby generating a stable low damping force.

Abstract: A shock absorber includes: a damping valve that suppresses a flow of operating fluid due to the sliding of a piston to generate damping force; a bottomed tubular pilot case that forms a pilot chamber that causes pressure to act on the damping valve in a valve closing direction, together with the damping valve; and an annular seal member (146) that is provided to be fixed to the outer circumferential side of a rear surface of the damping valve, and is fitted into a tube of the pilot case so as to be slidable and to be in a liquid tight manner. A part of the flow of the operating fluid is guided to the pilot chamber and opening of the damping valve is suppressed by the pressure of the pilot chamber. An annular concave portion (380) is formed on the outer circumferential side of the seal member (146), and an annular convex portion (385) is formed on the inner circumferential side of the seal member (146).

Abstract: In response to extension and compression of a piston rod, a piston slidingly moves in a cylinder, causing a flow of hydraulic oil. The hydraulic oil flow is controlled by a disk valve to generate a damping force. An elastic seal member fixed to the rear side of the disk valve is fitted to a recess in a pilot body to form a pilot chamber. The valve-opening operation of the disk valve is controlled by the pressure in the pilot chamber. The elastic seal member has an extension extended and fixed to the front side of the disk valve. Thus, forces acting on the rear and front sides of the disk valve due to shrinkage of the elastic seal member during fixing process balance and cancel each other out. Accordingly, it is possible to prevent warping of the disk valve and to obtain stable damping force characteristics.

Abstract: This suspension device is provided with a shock absorber (5) that is capable of altering damping force using the position of a piston rod (18) such that at least any one of the following characteristics are achieved, namely, first characteristics in which, within a range where the piston rod (18) is extending out from a cylinder (11) beyond a first predetermined position, the extension-side damping force is in a soft state and the compression-side damping force is in a hard state, and second characteristics in which, within a range where the piston rod (18) is retracted inside the cylinder (11) beyond a second predetermined position, the extension-side damping force is in a hard state and the compression-side damping force is in a soft state; and an operating force adjustment mechanism that is capable of adjusting at least one of the operating force in the roll direction of a vehicle, and the operating force in a pitch direction of the vehicle.

Abstract: An elastic seal member fixedly attached to a back surface side of a disk valve is fitted in a recessed portion of a pilot body, by which a pilot chamber is formed. A valve opening of the disk valve is controlled by an inner pressure in the pilot chamber. The elastic seal member includes a thick proximal portion and a thin lip portion. A seal portion protruding on an outer circumferential portion of the lip portion is in sliding contact with an inner circumferential portion of an outer cylindrical portion of the pilot body. Deflection of the thin lip portion can reduce sliding resistance while ensuring a sealing performance of the seal portion.

Abstract: PROBLEM Provided is a damping force control type shock absorber capable of obtaining an appropriate damping force even in the event of a failure independently of the stoke of a valving element of a solenoid valve. MEANS FOR SOLVING A piston 5 having a piston rod 6 connected thereto is fitted in a cylinder 2 having hydraulic oil sealed therein, and a flow of hydraulic oil induced by movement of the piston 5 is controlled by a damping force generating mechanism 26 to generate a damping force. In the damping force generating mechanism 26, damping force is generated by a pilot-type main valve 27 and a normally-open pilot valve 28 which is a solenoid valve, and the damping force is adjusted by energization of a coil 37. A fail-safe valve 100 is provided downstream of the pilot valve 28. During normal operations, the fail-safe valve 100 opens the flow path through excitation of the coil 37 of the pilot valve 28.

Abstract: In a friction member (22), a base section (92) is constituted by a bottom section (101) and a tube section (102). The bottom section (101) has a bored disk shape, and the tube section (102) has a cylindrical shape extending from an outer circumferential side of the bottom section (101) in the axial direction. An elastic rubber section (91) has a minimum inner diameter section (137), diameter expanding sections (138), (139) which are disposed at each side in the axial direction of the minimum inner diameter section (137). A tube section adhering surface (126) is installed at outer circumferential side of a tube section (102). A cutout section (151) is at least partially formed at a bottom section adhering surface (128) fixed to the bottom section (101) and the tube section (102) side of an open surface at an opposite side in the axial direction, and a deepest section (155) of the cutout section (151) is shallower than a position in the axial direction of the minimum inner diameter section (137).

Abstract: A shock absorber has an inclined surface that is inclined to a moving direction of the free piston in at least one of a free piston contact surface of a free piston with which an elastic body is in contact and a housing contact surface of a housing with which the elastic body is in contact. A shortest distance between the free piston contact surface and the housing contact surface is changed by movement of the free piston.

Abstract: An elastic seal member fixedly attached to a back surface side of a disk valve is fitted in a recessed portion of a pilot body, by which a pilot chamber is formed. Then, vale opening of the disk valve is controlled by an inner pressure in the pilot chamber. The elastic seal member includes a thick proximal portion and a thin lip portion. A seal portion protruding on an outer circumferential portion of the lip portion is in sliding contact with an inner circumferential portion of an outer cylindrical portion of the pilot body. Deflection of the thin lip portion can reduce a sliding resistance while ensuring a sealing performance of the seal portion.

Abstract: A damping force is generated by controlling a flow of oil caused by a sliding displacement of a piston in a cylinder with the aid of a disk valve, against extension and compression of a piston rod. An elastic seal member, fixedly attached to a back surface side of the disk valve, is fitted in a recessed portion of a pilot body, by which a pilot chamber is formed and valve opening of the disk valve is controlled by inner pressure in the pilot chamber. The elastic seal member is in abutment with a bottom portion of the recessed portion, and the disk valve is urged toward inner and other seat portions by elasticity of the elastic seal member. This configuration ensures that the disk valve can be closed without a set load provided from deflection of the disk valve, thereby generating a stable low damping force.

Abstract: A tube having sealing ring grooves formed by a sequential rotational process and a shock absorber including the tube, in which durability of a sealing ring fitted in each of the sealing ring grooves is enhanced. An inclination angle (?1) formed with respect to a plane (PL1) perpendicular to an axis of a separator tube by a side surface of the sealing ring groove, which is located on an opening end side of the separator tube, is set to 8° or more. With this, a maximum tensile stress to be applied to an O-ring can be reduced to be smaller than a maximum tensile stress in a case of using a backup ring. As a result, the durability of the O-ring can be set equivalent to or enhanced to be higher than durability in the case of using the backup ring.

Abstract: A minimum length-side property in which an extension-side damping coefficient signifies a hard state in a range (Aa0) where the piston rod enters further inside the cylinder than a minimum length-side predetermined position (Sa1), and a maximum length-side property in which the extension-side damping coefficient signifies a soft state in a range (Aa4) where the piston rod extends further outside the cylinder than a maximum length-side predetermined position (Sa4) are included. An extension-side damping force property between the minimum length-side predetermined position (Sa1) and the maximum length-side predetermined position (Sa4) includes a part (Sa1 to Sa2, Sa3 to Sa4) in which a damping coefficient change rate with respect to a stroke of the piston rod is large and a part (Sa2 to Sa3) in which the damping coefficient change rate is small.

Abstract: A suspension system, which is used together with a vehicle including a vehicle body, a front wheel, and a rear wheel, includes a mechanical damping force variable shock absorber disposed between the vehicle body and the front wheel and configured to mechanically change a damping force, and a damping force adjustable shock absorber disposed between the vehicle body and the rear wheel and configured to adjust a damping force by an actuator.

Abstract: For the extension and compression strokes of a piston rod, a damping force generating mechanism generates a damping force by controlling the flow of hydraulic oil caused by the sliding movement of a piston in a cylinder. The damping force generating mechanism has a pilot-type main valve, a pilot-type control valve, and a pilot valve. The main valve has a pilot chamber into which the oil is introduced to adjust the valve-opening pressure of the main valve by the pressure in the pilot chamber. The control valve has a pilot chamber into which the oil is introduced to adjust the valve-opening pressure of the control valve by the pressure in the pilot chamber. The pilot valve controls the pressure in the pilot chamber of the control valve. The control valve controls the pressure in the pilot chamber of the main valve.

Abstract: A damping force adjustable shock absorber includes a cylinder sealingly containing hydraulic fluid, a piston slidably fitted in the cylinder, a piston rod coupled to the piston, and a damping force generation mechanism configured to generate a damping force by controlling a flow of the hydraulic fluid caused by a sliding movement of the piston. The damping force generation mechanism includes a pilot-type damping valve. A valve body of the pilot-type damping valve and a plurality of annular members including a member forming a pilot chamber are fixed to a shaft-like member inserted therethrough with a space formed between one of the annular member and the shaft-like member, and at least one of a filter and a fixed orifice is disposed in the space.

Abstract: A shock absorber includes a first passage (111) or (112) and a second passage (32), (99) or (235) in communication with each other and configured to allow a working fluid to flow between two chambers (16) and (17) based on movement of a piston (15), and a passage area adjustment mechanism (101) or (236) configured to adjust a passage area of the second passage (99) or (235) depending on a position of a piston rod (18) is installed to have at least one of a maximum length-side property in which an extension-side damping force becomes soft and a compression-side damping force becomes hard in a range in which the piston rod (18) extends to an outside of a cylinder (11) farther than a maximum length-side predetermined position, and a minimum length-side property in which the extension-side damping force becomes hard and the compression-side damping force becomes soft in a range in which the piston rod (18) enters an inside of the cylinder (11) further than a minimum length side predetermined position.

Abstract: This suspension device is provided with a shock absorber (5) that is capable of altering damping force using the position of a piston rod (18) such that at least any one of the following characteristics are achieved, namely, first characteristics in which, within a range where the piston rod (18) is extending out from a cylinder (11) beyond a first predetermined position, the extension-side damping force is in a soft state and the compression-side damping force is in a hard state, and second characteristics in which, within a range where the piston rod (18) is retracted inside the cylinder (11) beyond a second predetermined position, the extension-side damping force is in a hard state and the compression-side damping force is in a soft state; and an operating force adjustment mechanism that is capable of adjusting at least one of the operating force in the roll direction of a vehicle, and the operating force in a pitch direction of the vehicle.

Abstract: In response to extension and compression of a piston rod, a piston slidingly moves in a cylinder, causing a flow of hydraulic oil. The hydraulic oil flow is controlled by a disk valve to generate a damping force. An elastic seal member fixed to the rear side of the disk valve is fitted to a recess in a pilot body to form a pilot chamber. The valve-opening operation of the disk valve is controlled by the pressure in the pilot chamber. The elastic seal, member has an extension extended and fixed to the front side of the disk valve. Thus, forces acting on the rear and front sides of the disk valve due to shrinkage of the elastic seal member during fixing process balance and cancel each other out. Accordingly, it is possible to prevent warping of the disk valve and to obtain stable damping force characteristics.