| 摘要 |
<p>Provided is a hydraulic shock absorber enabling an increase in a variable range of both damping forces produced in an extension stroke and a compression stroke thereof. A cylinder (1) filled with hydraulic oil is divided into first and second oil chambers (101) and (102) by a piston (2), and a main valve (4) is disposed in a main passage (81) of the piston (2). An extension side pilot chamber (6) urging a spool (8) in a valve-closing direction at pilot pressure introduced thereinto through a first orifice (32) in the extension stroke and a compression-side pilot chamber (7) urging the spool (8) in the valve-closing direction at pilot pressure introduced thereinto through a second orifice (43) in the compression stroke are formed at a back face of the spool (8) of the main valve. Also, the shock absorber comprises a pressure-receiving portion for receiving high pressure in the extension stroke and urging the spool (8) in a valve-opening direction against the pilot pressure and a pressure-receiving portion for receiving high pressure in the compression stroke and urging the spool (8) in the valve-opening direction against the pilot pressure. In addition, the shock absorber comprises an extension-side poppet valve (11) for regulating the pilot pressure in the extension stroke, a compression-side poppet valve (10) for regulating the pilot pressure in the compression stroke, and a solenoid (71) for urging to reduce initial loads of springs (9) of the extension-side and compression-side poppet valves (11) and (10) by passing current therethrough.</p> |
