| 摘要 |
1343958 Antiskid braking systems ROBERT BOSCH GmbH 3 May 1971 [6 May 1970] 12721/71 Heading F2F In an antilock compressed air braking system a valve assembly 1 is provided between a drivers valve 5 and a brake cylinder 27 comprising a solenoid valve 4 responsive to an antilock signal derived from a sensor and acting as a pilot valve for two double seat valves 2, 3 each of which respectively controls the supply of air to and from one of chambers 26, 29 of the brake cylinder. During normal braking conditions air passes from a reservoir 6 to chamber 26 by way of drivers valve 5, line 24 and ports 23, 25 of valve assembly 1 to move a diaphragm 28 thereby actuating the brake. On reception of a skid an electrical signal passed to solenoid valve 4 causes a closure member 9 to seat at 10 allowing air to pass from reservoir 6 to act on two pistons 13, 18 of valves 23. Return spring 18<SP>1</SP> acting on piston 18 is weaker than the spring 13<SP>1</SP> acting on piston 13, and piston 18 is depressed first to cause a closure member 19 to seat at 20 and allow air in chamber 26 to be vented through connection 22. Piston 13 is then depressed and air passes via a port 8 and line 30 to the chamber 29 to move diaphragm 28 upwardly and release the brake. On receleration of the wheel solenoid valve 4 is deactivated and air acting on pistons 13, 18 is vented through connection 12. Air in chamber 29 is vented through line 30 and the hollow stem 14 of valve 2. In a further embodiment the second valve 3 is replaced by a double non-return valve. Alternatively a single hollow stem 36, Fig. 3 (not shown), may be used for the double seat valves situated at either end of the stem. |
