| 摘要 |
932,269. Fluid-pressure brakes. ANDRE CITROEN S.A. Jan. 24, 1962 [Jan. 24, 1961], No. 2716/62. Class 103 (1). A valve 5 inserted in a conduit leading from a master cylinder 4 to the brake cylinders of the rear axle 2 of a road vehicle for limiting hydraulic pressure in the rear brake cylinders when the pressure supplied to the brake cylinders of the front axle 1 rises above a predetermined value, comprises a valve stem 10 slidable in a casing 9 and having a head 11 adapted to seat on the upper edge 12 of an opening 13 to which the master cylinder is connected via a passage 15. The rear wheel brake cylinders are connected via a passage 16 to a chamber 14 which is closed off from the chamber 13 when the valve is seated. A spring 21 whose compression is varied in accordance with the load on the rear axle acting via the suspension, a spring 8, lever 6, piston 24, restricted passageways 26 in a plate 25, and piston 23 maintains the valve open in the absence of hydraulic pressure. As the master cylinder pressure rises it acts over the cross-section of stem 10, against spring 21, to close the valve at a pressure dependent on the load, after which the valve remains closed in spite of increasing pressure in chamber 13 until a pressure differential determined by the ratio of the diameter of the valve seat to the area of the valve stem is exceeded. This pressure differential is maintained at braking pressures in excess of the pressure required initially to close the valve. A one-way ball valve 20 disposed in a passage 19 interconnecting chambers 13, 14 allows release of pressure from the rear wheel cylinders when master cylinder pressure is reduced. |
