| 摘要 |
PURPOSE:To make a configuration simple as well as to make controlling torque uniform, which is to be developed for front and rear wheels at the time of back up by providing an electromagnetic proportion type liquid pressure control valve for the rear wheels with a back up mechanism actuated by means of the indicated pressure of an electromagnetic proportion type liquid pressure control valve for the front wheels. CONSTITUTION:In a condition that electromagnetic proportion type control valves 10 and 20 are out of order because of failures in an electrical control system and the like, a brake pedal is depressed beyond a definite stroke so that the mechanical connection is made with the front wheel control valve 10 via a link mechanism, and switch-over in a mechanical liquid pressure switch-over valve 21 is also made. As a result, the front wheel control valve 10 developes braking liquid pressure in response to the stroke of pedal footing, switching the valve positions of relay valves 22 and 23, supplying braking liquid pressure from the switch-over valve 21 to the rear wheel control valve 20 as pilot pressure, and supplies braking liquid pressure for the rear wheels to a rear wheel brake air cylinder 25b. This constitution can thereby make a configuration simple, and can also make controlling torque uniform, which is to be developed for the front and rear wheels before the time of back up. |
