GB961027A - Control means for epicyclic power transmission mechanisms - Google Patents

Abstract

961,027. Friction clutches; change-speed gear. A. C. WICKAM. Oct. 10, 19 [Nov. 30, 1959; Feb. 2, 1960], Nos. 40554/59. Headings F2C and F2D. A double clutch for use in motor cars or the like in combination with a planetary changespeed gear comprises a driving clutch member having an inner peripheral surface of frustoconical shape and a pair of complementary driven clutch members for frictional engagement with the frusto-conically shaped surface. In one form, a driving clutch member 2, Fig. 1, has a frusto-conical inner peripheral surface engageable by correspondingly shaped discs 7, 8 fast for rotation with concentric shafts 9, 10, respectively. Admission of fluid under pressure to a ring-shaped servo 5 forces a ring-piston rightwards of the Figure to act through a thrust bearing 6 and move the driving clutch member 2 against the bias of springs 14 into engagement with the driven clutch disc 7. Admission of fluid under pressure to a servo containing a ring-shaped piston 11 causes the latter to move the clutch disc 8 leftwards into engagement with the driving clutch member 2, compression of the springs 14 serving simultaneously to move the driving clutch member out of engagement with the driven clutch disc 7. In another form, a disc 36, Fig. 2, is mounted for rotation with but axial sliding motion upon the driving clutch member 2 and is biased by springs 37 to engage its frusto-conical surface with the driven clutch disc 7. Admission of fluid under pressure to a servo containing a ring-shaped piston 11 moves the latter leftwards of the Figure together with the driven clutch disc 8, which engages the frusto-conical surface of the driving disc 36 and then forces the driving disc leftwards, against the bias of the springs 37, out of engagement with the driven clutch disc 7. As shown in Fig. 1, the double clutch is combined with a five forward-ratio and reverse gear, the first ratio being obtained by engaging the clutch disc 7 with the driving clutch member 2 so that the shaft 9 and a sun gear s1 fast therewith rotate, the sun gear meshing stepped planet pinions 16 meshing a ring gear 16, stationed by manual engagement of a pawl 21 with teeth 24a on a disc connected through a ratchet clutch 25 with the ring gear, a carrier 17 mounting the planet pinions being fast on a driven shaft 18. Second ratio is established by disengaging the clutch 7 and instead engaging the clutch 8 so that a sun gear s2 fast upon the shaft 10 transmits drive to the stepped planet pinions 16, as before. To obtain the third ratio, fluid under pressure is admitted to a servo 29 containing a ring-shaped piston 28 which then engages a clutch-brake disc 26 with a fixed brake surface 27 to hold a reaction sun gear r1 stationary, stepped planet pinions, Fig. 1a (not shown), mounted in the driven carrier 17, meshing the reaction sun gear r1 and also the stepped planet pinions 16. The fourth ratio is established by disengaging the clutch 7 and instead engaging the clutch 8, to transmit drive through the sun gear s2. Fifth ratio (direct drive) is obtained by admitting fluid under pressure to a ring-shaped servo 33 containing a piston 32 which acts to slide a clutch disc 31 axially against the bias of springs 35 into engagement with the clutchbrake disc 26, and then disengage the latter from the brake surface 27, thus clutching the reaction sun gear r1 and the sun gear s2 together. For reverse, the pawl 21 is shifted manually into engagement with teeth 22 to station a ring gear 20 meshed by the planet pinions (not shown) also meshing the reaction sun gear r1 and the planet pinions 16, the clutch 7 being engaged to rotate the sun gear s1. Specification 915,396 is referred to.