| 摘要 |
<p>PROBLEM TO BE SOLVED: To completely prevent the delaying of oil pressure generation and a negative pressure generation by providing first and second three-way solenoid valves in an air pressure supply route reaching a booster in series in an upstream and downstream relation and branching an air pressure supply route reaching a master cylinder from between the solenoid valves. SOLUTION: Two-way type three-way solenoid valves 78 and 79 controlled by a computer built-in controller 71 are provided in the midway of an air pressure pipe 62 connected to an air tank 5 and reaching a shuttle valve 69 in series in an upstream and downstream relation. An air pressure pipe 70 is connected between the three-way solenoid valves 78 and 79 and then a second air pressure supply route (c) for supplying air pressure to a master cylinder 10 is formed. Thus, the three-way solenoid valves 78 and 79 are turned ON during the automatic breaking operation of a clutch 8 and air pressure is supplied through the air pressure pipes 62 and 70 to the master cylinder 10. Thereby, a second piston is pressed to move, a booster 7 is pressurized and a negative pressure generation in an oil pressure passage is prevented. Also, the delaying of oil pressure generation and the shortage of an pressure oil amount are prevented.</p> |
