Abstract: A leaf valve structure according to this invention comprises an annular valve seat, and a leaf that is seated on the valve seat under a predetermined elastic supporting force against a pressure of a working fluid on an inner side of the valve seat. A recessed depression portion having an opening portion on both an inner periphery of the valve seat and a seating surface of the leaf is formed in the valve seat, thereby creating a site where the pressure of the working fluid on the inner side of the valve seat can act more easily on a seating surface between the valve seat and the leaf valve. Accordingly, an effect of a surface adsorption force applied to the leaf valve by the valve seat on a cracking pressure can be suppressed, and as a result, the leaf valve can be lifted under a stable cracking pressure.

Abstract: A leaf valve structure according to this invention comprises an annular valve seat, and a leaf that is seated on the valve seat under a predetermined elastic supporting force against a pressure of a working fluid on an inner side of the valve seat. A recessed depression portion having an opening portion on both an inner periphery of the valve seat and a seating surface of the leaf is formed in the valve seat, thereby creating a site where the pressure of the working fluid on the inner side of the valve seat can act more easily on a seating surface between the valve seat and the leaf valve. Accordingly, an effect of a surface adsorption force applied to the leaf valve by the valve seat on a cracking pressure can be suppressed, and as a result, the leaf valve can be lifted under a stable cracking pressure.

Abstract: A check seal (53) for discharging working oil scraped off a piston rod (3) by an oil lip (52b) into an oil pool (A) of a hydraulic shock absorber to an oil reservoir (R) is disposed on the outside of the oil pool (A). The check seal (53) comprises an annular seat surface (4d) and an annular lip (53a) seated resiliently on the seat surface (4d). The annular seat surface (4d) comprises an annular main rib (11) and an annular inner rib (12), both of which project toward the annular lip (53a), such that an annular groove (21) is formed between the main rib (11) and the inner rib (12). By providing a pressure introducing passage (12a) to introduce a pressure inside the inner rib (12) to the annular groove (21), the check seal (53) exhibits a high working oil discharging performance and a high working oil sealing performance.

Abstract: There is provided a hydraulic damper including a receiving space formed between a rod guide of a cylinder and an insert metal, for temporarily retaining a working fluid leaked out from an oil chamber through a sliding gap of a rod. The hydraulic damper further includes a communicating path for communicating between a reservoir and the receiving space, and a check valve for allowing a flow of the working fluid only from the receiving space to the reservoir. Either one of a lip part of the check valve or a seat surface provided on the rod guide is formed with a sealing projected part protruding from a mutual contact surface.

Abstract: A double tube hydraulic shock absorber comprises: an outer tube; an inner tube; a base valve which is fitted and fixed to a base end of the inner tube; a lower cap provided so as to contact a leg portion of the base valve and seal a base end of the outer tube in an oil tight fashion; a piston rod inserted into the inner tube so as to be capable of an axial reciprocation; and a guide member attached to a top side of the outer tube and the inner tube so as to support the piston rod and apply an axial force on the inner tube. In this double tube hydraulic shock absorber, the leg portion of the base valve and the lower cap contact each other on a line of action of the axial force that is applied toward the base end of the inner tube.

Abstract: A check seal (53) for discharging working oil scraped off a piston rod (3) by an oil lip (52b) into an oil pool (A) of a hydraulic shock absorber to an oil reservoir (R) is disposed on the outside of the oil pool (A). The check seal (53) comprises an annular seat surface (4d) and an annular lip (53a) seated resiliently on the seat surface (4d). The annular seat surface (4d) comprises an annular main rib (11) and an annular inner rib (12), both of which project toward the annular lip (53a), such that an annular groove (21) is formed between the main rib (11) and the inner rib (12). By providing a pressure introducing passage (12a) to introduce a pressure inside the inner rib (12) to the annular groove (21), the check seal (53) exhibits a high working oil discharging performance and a high working oil sealing performance.

Abstract: There is provided a hydraulic dumper including an receiving space 15 formed between the rod guide 4 of the cylinder 1 and the insert metal 5 and for temporarily retaining the working fluid leaked out from the oil chamber R1 through the sliding gap of the rod 3, a communicating path 4d for communicating the reservoir R and the receiving space 15, and a check valve 9 for allowing the flow of the working fluid only from the receiving space 15 to the reservoir R, wherein, either one of the lip part 9a of the check valve or the seat surface 4c provided on the rod guide 4 is formed with a sealing projected part 10, 11 protruding from the mutual contact surface.

Abstract: A double tube hydraulic shock absorber comprises: an outer tube; an inner tube; a base valve which is fitted and fixed to a base end of the inner tube; a lower cap provided so as to contact a leg portion of the base valve and seal a base end of the outer tube in an oil tight fashion; a piston rod inserted into the inner tube so as to be capable of an axial reciprocation; and a guide member attached to a top side of the outer tube and the inner tube so as to support the piston rod and apply an axial force on the inner tube. In this double tube hydraulic shock absorber, the leg portion of the base valve and the lower cap contact each other on a line of action of the axial force that is applied toward the base end of the inner tube.

Abstract: The invention provides a hydraulic shock absorber for controlling an attenuating force in a very low speed range and a medium or high speed range of the speed of a piston. A leaf valve for the high speed range and another leaf valve for the medium or high speed range are disposed for opening and closing movement at an exit end of a port formed in a partition wall member such as the piston. The leaf valve for the low speed range is supported at a rear face of an inner peripheral portion thereof for up and down floating movement on an upper face of a valve stopper. In the medium or high speed range, the leaf valve for the low speed range is deflected to move the inner peripheral portion thereof floatingly, which prevents the leaf valve from being deflected excessively and hence prevents a possible break of the leaf valve.

Abstract: The invention provides a hydraulic shock absorber for controlling an attenuating force in a very low speed range and a medium or high speed range of the speed of a piston. A leaf valve for the high speed range and another leaf valve for the medium or high speed range are disposed for opening and closing movement at an exit end of a port formed in a partition wall member such as the piston. The leaf valve for the low speed range is supported at a rear face of an inner peripheral portion thereof for up and down floating movement on an upper face of a valve stopper. In the medium or high speed range, the leaf valve for the low speed range is deflected to move the inner peripheral portion thereof floatingly, which prevents the leaf valve from being deflected excessively and hence prevents a possible break of the leaf valve.

Abstract: The rear shock-absorber unit which suspends the rear wheel of motorcycles is provided with a device for adjusting the damping force produced by the hydraulic damper. The said adjusting device incorporates a passage which is provided in the piston rod so as to permit the fluid to flow throughout the upper and lower working chambers of the damper cylinder which are separated by the piston, and an adjusting member which is engaged, rotating freely, with the piston rod and covers one of the ports of the passage. The said adjusting member has a group of orifices, different in diameter, which connect successively to the said passage in the piston rod, and click stops which, at their respective positions, constrain the relative rotary motion between the adjusting member and piston rod. When the hydraulic damper reaches the extreme of expansion, it is pressed against a seal holder or stop rubber attached to the upper end of the damper cylinder to prevent the rotary motion.