Patent GB-780990-A (GB)
Title: Improvements in or relating to change-speed transmissions
Inventor: FLINN GEORGE E
IPC: F16H37/08
Filed: 1954-11-05
Abstract: 780,990. Change-speed gear. BORGWARNER CORPORATION. Nov. 5, 1954, No. 32058/54. Class 80 (2). An upshift pawl 34 of a planetary directoverdrive gear, arranged behind a manual three-speed gear on a vehicle, is moved automatically to upshift position by fluid-pressure supplied through a valve 40, which is automatically opened by a predetermined increase in fluid pressure supplied by an output driven pump 39 and rendered speed-responsive by a permanently open sharp-edged relief orifice 42, variable by an adjustable plug 66. Function summary.-The control automati-- cally conditions the gear for upshift above a predetermined vehicle speed, such upshift being driver-established by momentary acceleratorrelease. Accelerator kick-down-shift is provided through means which is wholly hydraulic except for the momentary electric disablement of the engine ignition for torque reversal. The manual lock-out 93 positively clutches together input and output shafts and exhausts fluid pressure. In overdrive setting the direct-drive is one-way. Gear arrangement.-This is similar to that normally provided with all-electric control. Input and output shafts 10, 11, carrying respectively a planet carrier and ring gear 13, are permanently connected by a one-way roller clutch 18 for direct drive. For overdrive a freelymounted reaction sun 20 is held by the radiallyguided pawl 34 positively engageable with peripheral notches in a disc 35 which is splined to the sun 20, and frictionally carries a drag-ring 36 having balk-steps 37, Fig. 2, preventing such engagement until the sun 20 has come to rest and begun to reverse. Lock-out is by sliding the sun 20 axially to clutch teeth 23 thereon with teeth 24 on the planet-carrier, such sliding being through a spring 28, shift-rail 27, lever 33 and manual button 93. Fluid system.-The plunger pump 39, driven by an output-mounted eccentric 44, supplies oilpressure through an external pipe to a passage 65 of a forwardly-mounted valve-block, said passage 65 exhausting to a sump-passage 67 through the sharp-edged regulating orifice 42, Fig. 10, controlled by the fixed cored restrictor 66 manually adjustable to vary the pressurespeed relation in the supply passage 65. In the same block are a pawl-actuating piston 68 supplied through the pressure-responsive valve 40 and a manual valve 43 for exhausting the pressure. Operation.-On exceeding a predetermined adjustable output speed, supply pressure 65 is sufficient to open the spring-loaded twoposition, pressure-responsive valve 40, which opens a passage leading supply pressure to the left face of the pawl-actuating piston 68, Fig. 2, which slides on a pawl-connected rod 72 which it moves radially inwards through an inner delay spring 74. The pawl 34, loaded by the spring 74, is balked on one of the steps 37 of the dragring 36, which releases it for engagement with the notched sun-disc 35 only when the driver creates overrun by momentary accelerator release to cause the sun 20 to come to rest and begin to reverse, whereupon the pawl 34 engages under spring load and establishes two-way overdrive. For kick-down-shift, overtravel of the accelerator. 88, through a bellcrank 90, Fig. 11, cable 91, opens the manual valve 43 to exhaust the pressure, thus releasing the piston 68 for return by an outer spring 70. Such return, is possible only on torque-reversal produced by kickdown closure of a switch 96, which, in conjunction with a switch 77, closed at 81 by the preceding engaging movement of the pawl rod 72, short-circuits the contactbreaker 104 of the usual engine ignition system, thus disabling the latter until the consequent release movement of the pawl 34 re-opens the switch 77. The manual lock-out button 93 which operates the lock-out clutch lever 33, also operates the manual exhaust valve 43.