| 摘要 |
1,191,429. Pressure regulating valves; valves. ZAHNRADFABRIK FRIEDRICHSHAFEN A.G. 8 Oct., 1968 [19 Oct., 1967], No. 47667/68. Headings F2D and F2V. An hydraulic device for controlling pressure build-up in a clutch or brake acting as a gearbox shift element comprises a pressure regulating valve 1, Fig. 1 having two piston portions 1À1, 1.2 respectively controlling supply and vent passages 7, 11 which have a regulated pressure take-off passage 8 disposed therebetween, the valve being loaded with the regulated pressure against the action of a compression spring 6 disposed between the valve 1 and a larger diameter piston 2 which is also loaded by the regulated pressure and a passage 12, which in the rest position of the valve 1 is connected to a vent 13, between the larger piston loading chamber 5 and a chamber 3 of the valve piston facing the larger piston. When pump pressure is supplied via passage 7 the initial take-off pressure in passage 8 is dependent on the pre-stressing of the compression spring 6. As the regulated pressure rises the pressure supplied to chamber 4 via passage 9 causes the valve 1 to move to the left further compressing spring 6, closing supply passage 7 and opening vent passage 11. Similarly the pressure supplied via passage 10 and throttle 10À1 to chamber 5 causes the piston 2 to move to the right also compressing the spring 6. The opening of vent passage 11 and closing of supply passage 7 is dependent on the equilibrium between spring force and loading pressure, the time taken to achieve the regulated pressure being dependent on the sizes of throttle 10À1 and piston 2. When the clutch is vented pressure falls in passages 8, 9, 10 and valve piston 1À2 moves to allow the pressure in chamber 5 to collapse quickly via passage 12 and vent passage 13 causing piston 2 to be moved back to its Fig. 1 position by spring 6. In a modification to give a final abrupt rise of regulated pressure up to the supply pressure the piston (2), Fig. 3 (not shown), engages an elongated valve stem (15) to cause the valve piston (1À1) to open the supply passage (7). In a further modification to give a non-linear rise of regulated pressure passage 10, Fig. 1, is replaced by a passage (14), Fig. 4 (not shown), including a throttle (14À1), arranged directly between the supply passage 7 and the chamber (5). |
