Shock absorber
AssigneeYamaha Hatsudoki Kabushiki Kaisha
InventorAkira Tanaka
Life of this patent
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Abstract
An electrically operated shock absorber that includes a pilot chamber and pilot valve which pilot valve is acted on by an electrical solenoid so as to control the damping characteristics of the shock absorber. An arrangement is provided for preventing total bumping of the pressure in the pilot chamber in the event of electrical failure and substituting a pressure responsive valve for controlling the damping characteristics when the electrical failure occurs. An improved piston construction and valving arrangement is also disclosed.
Claims18
An electrically controlled shock absorber comprised of a cylinder assembly, a piston assembly received in said cylinder assembly and dividing said cylinder assembly into a pair of spaced apart piston fluid chambers, means defining a flow path between said piston fluid chambers including a pressure responsive control valve controlling such flow path, said pressure responsive control valve having a control portion subject to pressure in a pilot chamber for urging said pressure responsive control valve to a closed position, a pilot valve, an electric solenoid for controlling the pressure at which said pilot valve opens for communicating said pilot chamber with a lower pressure area for reducing the pressure in said pilot chamber holding said control valve in its closed position, a fail safe arrangement for closing the communication of said pilot chamber with said lower pressure area and establishing another path to a low pressure area, a pressure responsive valve in said another path for controlling the pressure in said pilot chamber and the pressure at which the pressure in said pilot chamber can be relieved through said another path, said pilot valve being comprised of a first portion cooperable with a pilot valve seat for controlling the opening and closing of the communication of said pilot chamber with said lower pressure area a second portion for closing the communication of said pilot chamber with the lower pressure area and wherein movement of the pilot valve in one direction causes said first portion to close said pilot valve seat before the second portion closes the communication of the pilot chamber with the lower pressure area, and positive stop means for limiting the movement of the pilot valve in the one direction upon the failure of electric power, said positive stop means being disposed in an area spaced from said pilot valve first and second portions in an area that does not experience the flow between the piston fluid chambers in any condition of the pilot valve.
An electrically controlled shock absorber comprised of a cylinder assembly, a piston assembly received in said cylinder assembly and dividing said cylinder assembly into a pair of spaced part piston fluid chambers, means defining a flow path between said piston fluid chambers including a pressure responsive control valve for controlling such flow path, said pressure responsive control valve having a control portion subject to pressure in a pilot chamber for urging said pressure responsive control to a closed position, a pilot valve, an electric solenoid for controlling the pressure at which said pilot valve opens for communicating said pilot chamber with a lower pressure area for reducing the pressure in said pilot chamber holding said control valve in its closed position, positive stop means for limiting the opening movement of the pilot valve upon the failure of electric power, said positive stop means being provided in the area between said pilot chamber and said lower pressure area and being formed in part by said pilot valve and by an inclined stop surface engaged by said pilot valve, and a fail safe arrangement for closing the communication of said pilot chamber with said lower pressure area and establishing another path to a low pressure in said pilot chamber and the pressure at which the pressure in said pilot chamber can be relieved through said another path, said piston assembly includes a generally hollow piston member closed at one end by an integral wall and closed at its other end by a subassembly comprised of a lower piston member forming said pressure responsive control valve consisting of a valve seat for communicating said piston chambers with each other and a bore slidably supporting a control valve element having a portion engageable with said valve seat for controlling the flow therethrough, said control valve element being formed with an integral bore forming in part the pilot chamber and further including passage means for selectively communicating said piston chambers with said pilot chamber including pressure responsive check valve means for permitting only the higher of the pressure in the piston chambers to communicate with the pilot chamber.
Dependencies are inferred from the claim text.