Patent GB-907201-A (GB)
Title: Transmission mechanism
Inventor: DABICH SAM
IPC: F16D48/02
Filed: 1960-04-19
Abstract: 907,201. Change-speed and clutch control. BORG-WARNER CORPORATION. April 19, 1960, No. 13711/60. Class 80 (2). An automatic vehicle transmission includes a fluid-pressure operated main clutch 18 controlled by the gear shift lever 47 through a solenoid valve 71, the fluid supply system including a pressure regulating valve 72 for maintaining the fluid at a high pressure prior to movement of lever 47 and for changing it to a low value when lever 47 is moved to initiate a gear shift. Transmission.-The input shaft 10 is connected to the output shaft 11 through a torque converter 16 in series with intermediate shafts 12, 13, the main clutch 18, countershaft gearing 15 and gear-box 20. Shafts 12, 13 may be connected by the clutch 18 through a sleeve shaft 14. A fluid supply pump 17 is driven by input shaft 10. Clutch details.-The clutch 18 comprises a cone friction element 31 splined to a drum 30 and engageable with a pressure member 34 against a release spring 39 by a member 37 integral with an annular piston 36 supplied with pressure fluid through passages 42. In addition a manually engageable clutch 19 is provided in parallel with main clutch 18 for push-starting in the event of failure of the fluid supply. This clutch consists of a disc 43 with peripheral splines engageable with corresponding internal splines in member 34, and is operable by a member 44 connected to a Bowden cable 45 and control knob 46. Gear shift machanism.-Gear shift lever 47 is mounted on a shaft 48 carrying a radial arm 54 with an integral arcuate portion 56 located outside but adjacent the steering column 49, the member 56 having a series of notches 57 engageable by a ball detent 58 in the desired gear selecting positions., Shaft 48 also carries an arm 50 having an elongated slot lost-motion connection 50a with a link 51 operating the shift arm 52 on gear-box 20. This lost-motion connection provides a time lag between disengagement of the clutch and a gear shift. Hydraulic control system.-Pump 17 delivers to torque converter 16 through a pipe 112 and to the supply passages 42 of a clutch 18 through a pipe 86, the latter being under the control of the valve 71, actuated by a solenoid 70 controlled by a switch 64 in series with the ignition switch 69. Switch 64 is actuated by a ball 61 engageable with notches 60 corresponding with detent notches 57 and arranged at the edge of a sector 55 also carried by shaft 48. The pressure regulating valve 72 consists of spaced pistons 91, 92 with an interposed spring 105, the outer faces of the pistons being subjected to the pressure of fluid in the inlet pipe 88 and clutch supply pipe 86 respectively. Operation.-With ignition switch 69 closed, when ball 61 rides on the arcuate edge 59 of sector 55, i.e. in neutral (N) or between gear shifts, contact 64 is held closed so that solenoid 70 is energized to move valve 71 to the closed position against a compression spring 90. Under such conditions fluid from pump 17 passes through a restriction 111 to act on the left-hand face of piston 91 and move it to the right against spring 105, thereby opening an exhaust port 110 to establish a low pressure in pipe 87. Upon moving lever 47 to initiate a gear shift contact 64 is opened and valve 71 is also opened by spring 90, and the pressure in pipe 87 is communicated through pipe 86 to clutch 18 which is gradually engaged. The pressure in pipe 86 acting on the right-hand face of piston 92 moves the latter to the left, and spring 105 moves piston 91 to the left to close exhaust port 110, whereupon the pressure builds up to hold the clutch engaged. In effecting a gear change the lost-motion connection 50a in the shift linkage ensures operation of valve 71 in such a way as to cause drainage of the clutch-operating fluid, so that the clutch is fully disengaged before a shift is made to another gear ratio.