GB863651A - Improvements relating to disengageable clutch arrangements - Google Patents

Abstract

863,651. Ratchet clutches; change-speed gear. DAIMLER-BENZ A.G. June 3, 1958 [June 26, 1957], No. 17684/58. Class 80 (2). A lockable one-way friction clutch shown in Fig. 1 as a double clutch for selectively connecting gear-wheels 13, 14 of a change-speed gear to a shaft 12, which clutch engages on synchronism and disengages on torque reversal, has conical friction synchronizing surfaces 26 on the clutch elements and conical friction power-transmitting surfaces, which may as shown, be the same surfaces 26, or additional surfaces, which are selectively biased towards engagement when required, and subject to torque-responsive axial engaging thrust by interengaging inclined surfaces. A combined synchronizing and drive transmitting cone 17 has limited circumferential and axial freedom on each wheel e.g. 14 and cooperates with an internal coned shift sleeve 21 drivingly connected with the shaft 12 by pins 24 having two driving surfaces 36, 37 of different inclination driving the shift sleeve 21 according to its axial position. Thus when the sleeve 21 is selectively biased towards the wheel 14 through a spring 29 by hydraulic, pneumatic or electromagnetic means, the surfaces 26 contact in an initial synchronizing position in which sinusoidal balk surfaces 20 on the wheel 14 and cone 17 align, to prevent further axial movement, and the shift sleeve 21 is driven through the inclined surfaces 36 which provide a light torque-responsive axial thrust. When synchronism is achieved, the balk surfaces disalign and permit further rightward movement of the cone 17 against a spring 18, and the shift sleeve 21 is now driven by the more steeply inclined surfaces 37 which produce increased torqueresponsive thrust sufficient to enable the coned surfaces 26 to transmit full load torque. In this fully engaged position the shift sleeve 21 compresses the opposite spring 29 and the clutch remains in engagement after removal of the biasing force until the torque reverses, as by throttle closure or engagement of another gear,. whereupon the compressed spring 29 returns the shift sleeve to neutral position. The synchronizing cone 17 may be split radially and be resilient, and have a roughened or knurled friction surface. The hydraulic control means, as shown, comprises a shift finger 23 biased to a neutral position by the springs 29. For clutch engagement pressure fluid is supplied at 34 or 35 to move axially one of the two pistons 31 compressing one of the springs 29 to move axially the gear shift finger 23. In Fig. 2 (not shown) the control is effected electromagnetically, the sleeve 21 carries an armature concentric with three surrounding electromagnets for biasing the sleeve either to the left, right or holding it in the neutral position. The free-wheel action may be overridden by locking the shift sleeve in the engaged position providing torque transmission in either direction. In Fig. 3 two double clutches 64, 61 as above described, and one such single clutch 65 are shown in a change-speed countershaft gear providing three reduced forward ratios, reverse and direct drive respectively. An input driven drum 46 drives through disc clutches 47, 48 and concentric shafts 49, 52 to countershafts 51, 54 each carrying two freely rotatable pinions 55, 56; 62, 63. The pinions 55, 62, 63 may be selectively clutched to their shafts to drive through pinions 57, 58 the output shaft 59 at reduced ratios, whilst the pinion 56 drives the pinion 58 through a reversing pinion 60. For direct drive the clutch 65 is engaged. Specifications 827,114 and 829,052 are referred to. Reference has been directed by the Comptroller to Specifications 827,114 and 829,052.