| 摘要 |
PURPOSE:To aim at the miniaturization of a device, by installing a bypass passage, provided with a variable aperture in bypassing a second variable aperture, in a hydraulic bridge circuit installing two variable apertures to operate in response to steering torque, and controlling this variable aperture by differential pressure between both ends of the specified fixed aperture. CONSTITUTION:A control valve 13, which controls a power cylinder 12 generating steering torque, has a hydraulic bridge circuit 14 connecting four passages L1-L4 in a ring form, and connects connecting points CA1, CA2 on a diagonal of the one side to a hydraulic pump 10 and a reserve tank 11. In addition, variable apertures 1L and 1R are installed in these passages L1 and L2 side by side, and also variable apertures 2L, 2R, 3L and 3R are installed in the remaining passages L3 and L4. In this case, a bypass passage L5 is formed between these variable apertures 2L and 3L as well as between 2R and 3R, and a third variable aperture 4 is installed in this passage L5. This variable aperture 4 is controlled for its drive by an actuator 7 operating in response to differential pressure in a differential pressure generating fixed aperture 6. |
