| 摘要 |
1,155,592. Hydraulically actuated disc brakes. GIRLING Ltd. 23 July, 1966 [26 June, 1965], No. 27179/65. Headings F2E and F2F. In a motor vehicle hydraulic braking system employing a master cylinder, a servo arrangement is provided by which a servo pressure, produced by a piston and cylinder arranged within a brake having an hydraulic actuator supplied by the master cylinder, is applied to the master cylinder piston in the brake applying direction. The brake is preferably a disc brake which, as shown in Fig. 4, comprises a generally U-shaped caliper 10 straddling a brake disc and carrying friction elements attached to pistons which work in a pair of cylinders 24 one cylinder on each side of the brake disc (Fig. 1, not shown). The limbs of the caliper are of unequal length (Fig. 2, not shown), the longer limb being bifurcated and being mounted on, for limited relative movement to a fixed post 38. The mounting means comprises a pivot pin 40 which is provided at one end with a plug 42 to co-operate with a spring-biased piston 44 in an hydraulic cylinder 35 of the caliper. The pivot pin 40 is urged in a direction away from the cylinder 35 by attaching to its other end a spring-loaded bolt 52. When the brake is actuated the caliper is urged in a direction to compress the springs which co-operate with the bolt 52 thus urging the plug 42 against the piston 44 and hence increasing the pressure in the cylinder 35. This increased pressure is fed to an annular chamber 111 Fig. 5, in the master cylinder 74 to increase the braking pressure. When the master cylinder 74 is inoperative its working chamber 110 is in communication with a reservoir (not shown) through a valve 86, 90, ports 92, a tilting valve 100 and a passage 98. Actuation of the master cylinder by push rod 76 closes valve 86, 90 and allows the tilting valve to close. The hydraulic connection 142 between the annular chamber 111 and the cylinders 35 of two brakes as described above includes a pressure compensator 130 having inputs 126, 148 from the respective cylinders 35 and a connection 154 to atmosphere, or to the fluid reservoir. The compensator provides hydraulic fluid to compensate for the volume increase in the chamber 111 when the piston 72 is actuated, prior to the establishment of a servo pressure in the connection 142. The brake may also be actuated by a mechanically or hydraulically operated lever through a thrust member of adjustable length, the thrust member acting on one friction member only. |
