Patent GB-1414021-A (GB)
Title: Transmission with fluid retarder and controls
IPC: F16D65/78
Filed: 1973-10-04
Abstract: 1414021 Hydrodynamic brakes in vehicle transmissions GENERAL MOTORS CORP 4 Oct 1973 [28 March 1973] 46316/73 Heading F2E A transmission includes a transmission drive train having a fluid-drive device with inlet and outlet, e.g. torque converter 21, Fig. 5, a fluid retarder 10 connected to the drive train and having at least one chamber formed by a bladed stator and a bladed rotor 12, Fig. 1, driven by the drive train, the, or one, stator having an inlet flow passage 71 conforming to certain requirements and an outlet passage 72, 73 conforming to certain other requirements circumferentially spaced therefrom, a cooler 122, Fig. 5, having a flow restriction between its inlet and outlet and a low pressure regulator valve 98 connected (indirectly) to its outlet, a regulated fluid pressure supply 78, 76, 84 connected via the operating chamber of the torque converter 21 to the cooler inlet, and a retarder control valve 101, Fig. 5, having connections to the retarder inlet and outlet and the cooler inlet and outlet, the valve being operative from a "retarder off" position through a partial retarding phase to a "retarder full on" position, movement of the valve in this sense serving to produce progressive increase of retarder inlet pressure. The valve is manually actuated. In the "retarder off" position the valve element 103 is located to the left of the position shown in Fig. 5, and in that case the retarder outlet line 117 is connected to exhaust 116 (which communicates with sump 78) the torque converter outlet line 88 is connected only to the cooler inlet and disconnected from the retarder outlet, the retarder inlet line 124 is disconnected (permanently) from the retarder outlet line 117 and in this valve position is blocked, and the cooler outlet line 126 (and hence the torque converter outlet line) is disconnected from the retarder inlet line 124. Also the full diameter portion 135 of land c lies in the bore between the cooler outlet port 127 and a port 132 communicating with an exhaust 133, but port 127 is permanently in communication with low pressure regulator valve 98 communicating (indirectly) with sump 78. A vent 138, Fig. 1, connects the retarder interior with atmosphere, so the retarder is devoid of liquid during the "retarder off" phase. On initial movement of valve element 103 from "retarder off" position, land a disconnects ertarder outlet line 117 from exhaust 116 and movement of land c permits connection between the cooler outlet line 126 and retarder inlet line 124. However, the widest and deepest portions of tapered recesses 134 on land c are now located in the bore between ports 127 and 132, so the restriction of flow to exhaust 133 (see below) is at a minimum. In this partial retarding phase, the significant liquid flow paths are as follows: sump 78, pump 76, valve 84, torque converter inlet 87, torque converter 21, outlet 88, cooler 122, port 127, and from port 127, three flows in parallel: (a) retarder inlet 124, retarder 10, retarder outlet 117 to join liquid from converter outlet 88 to the cooler inlet, (b) line 97 to pressure relief valve 98 from which excess passes to the sump 78, and (c) past recesses 134 to exhaust 133 communicating with sump 78. On further movement of valve element 103 to the right, flow (c) referred to above is progressively reduced as the narrower and shallower portions of recesses 134 occupy the bore between ports 127 and 132, until, in the "retarder full on" position shown, a full-diameter portion 130 of land c occupies the bore, and flow (c) ceases altogether. Retarder inlet pressure is now at a maximum value governed by valve 98 (e.g. 55 p.s.i.).  In retarder 10, liquid from the righthand chamber 51 (fed with liquid at 71) passes through a series of passages 74, formed in rotor 12, in a part-axial, part-outwardly-radial direction into the left-hand chamber 52. Outlet passages 72, 73, from the respective chambers communicate with the common outlet line 117, Figs. 1, 5. Recesses 134 in land c of valve element 103 may have a profile different from a simple taper so that retarder power capacity varies as a straighter of straight-line function of valve movement (Fig. 6, not shown).