GB656054A - Improvements in or relating to transmissions and methods for changing the speed ratios through a transmission - Google Patents

Abstract

656,054. Controlling change-speed gearing. BORG-WARNER CORPORATION. July 30, 1946, No. 22661. Convention date. Aug. 1, 1945. [Class 80(ii)] A change-speed gearing includes underdrive and planetary overdrive gear trains whichwhen connected in series give e substantially one-to-one drive through the gearing to allow smooth engagement of a positive direct drive clutch, the overdrive gear train being rendered operative by a slipping coupling such as a friction brake, and being also used to provide an overdrive through the gearing. As shown, applied to a motor vehicle transmission gearing, a gear 25, Fig. 1, on the inpui shaft 10 meshes a gear 26 on a layshaft 19 which drives back through gears 28...30 to an intermediate shaft 16 sleeved on the output shaft 11. The gears 29... 30 mesh alternately, directly for first speed and through an idler 32 for reverse respectively a gear 31 slidably slpined on the shaft 16. The gear 28 is in constant mesh with a gear 34 rotatably mounted on a member 33 fixedly splined on the shaft 16. The member 33 has slidably splined thereon one movable member 43 of a multiple clutch having a second movable member 40 slidably splined on the shaft 11. The members 44, 40 are indendently operated by striking collars 52, 53, the latter rotating with the member 43 and controlling the member 40 through a rod 48 passing through a longitudinal slot on the member 43 and engaging an annular recess in the member 40. The members 44, 40 have clutch teeth 46, 41 co-acting with clutch teeth 36, 37 on the gear 25, and the member 40 and gear 34 have clutch teeth 42, 38 co-acting with the splines on the member 43. The shafts 16, 11 are connected by a forwardly-driving one-way roller clutch 18 bridged by a planetary overdrive comprising a planet carrier 64 on the shaft 16 whose planets mesh an annulus 61 on the shaft 11 and a reaction sun 62 freely journalled on the shaft 11 and stationable by a brake 66. Operation. In neutral gear, Fig. 1, the sliding gear 31 and clutch teeth 36, 37, 38 are disengaged as shown. To engage second gear through the underdrive train 25, 26, 28, 34, the member 43 is slid to the right to engage the teeth 38, the drive being positive or freewheel according to whether the teeth 42 are still engaged to transmit a direct drive to the shaft 11 or are freed by further movement of the member 43 to the position shown in Fig. 3, when drive is transmitted to the shaft 11 through the shaft 16 and roller clutch 18. To condition the transmission for third speed, which is a direct drive, the brake 66 is applied. with the freewheeling second speed in operation, to bring in the planetary set. The gearing ratios of the planetary set and the gears 25, 26, 28, 34 of the second speed differ mechanically only slightly or not at all, so that the shaft 11 is then rotated at a speed equal to or very slightly different from that of the shaft 10. The member 40 may then be slid to the left to engage the direct drive clutch teeth 37, 41 without shock, butt-ended engagement being avoided by chamfering the engaging edges of the teeth and by the slight relative speed difference if this exists. The brake 66 is then disengaged and the shaft 16 freed from the gear 34 by moving the member 43 to the left, the clutch parts being then in the position shown in Fig. 5. To condition the transmission for fourth speed, which is an overspeed, the member 44 is moved farther to the left to engage the clutch teeth 36, 46 and, after applying the brake 66 slightly to reduce the torque loading on the teeth 37, 41, the member 40 is: moved to the right to disengage these teeth and to bring the teeth 42 into register with a central cut-away in the splines on the member 43 as shown in Fig. 7. The shaft 11 is then driven directly from the shaft 10 through the shaft 16 and roller clutch 18. and upon applying the brakes 66 fully the planetary set becomes operative to drive the shaft 11 at an overspeed, the clutch 18 overrunning. In Fig. 8 (not shown), the gear 25 is rotatable on the shaft 10, which carries the clutch teeth 36, 32, and is driven therefrom through a hydraulic torque converter of the type having a reaction member which can rotate forwardly, the gearing ratio of the second speed gears being increased slightly to compensate for fluid slip between the shaft 10 and gear 25. As the converter provides torque multiplication, the first speed gear 29 may be dispensed with.