| 摘要 |
1454721 Change-speed control; clutch control CLARK EQUIPMENT CO 21 Jan 1975 [21 Jan 1974] 2614/75 Headings F2D and F2L To provide for gradual pressurization of alternately selectable fluid pressure operated devices, e.g. forward and reverse clutches 26a, 26b in a transmission, each conduit 28, 42 between a selector valve 22a and a device incorporates a modulator 34a, 34b and an accumulator 36a, 36b, and to ensure rapid resetting of an accumulator after its associated device has been de-pressurized each conduit 28, 42 has a connection 46, 48 with the other accumulator. The figure shows the movable parts of the apparatus in the positions they would occupy immediately after operation of the selector valve 22a to change from forward drive to reverse. Fluid is exhausted from the clutch 26a through a chamber 72a, the conduit 28, valve 22a and a conduit 44, and pressure fluid is delivered from a pump 14 through the valve 22a and conduit 42 to a chamber 72b and the clutch 26b, and also through the connection 48 to assist springs 87a, 88a in resetting the plunger 90a of the accumulator 36a to its rightmost position. Pressure in the chamber 72b has access through a passage 76b to a chamber bounded by a fixed closure 60b so that a movable member 66b is displaced against a spring 78b to control the rate of increase of pressure applied to the clutch 26b by opening a bleed 84b. The pressure also passes through a restriction 96b so that the accumulator plunger 90b is gradually displaced against its springs 87b, 88b, and the member 66b is ultimately returned to the position shown in which the clutch 26b is subject to maximum pressure. Similar actions controlling pressurization of the clutch 26a and resetting of the accumulator 36b take place on appropriate displacement of the selector valve 22a. |
