GB780155A - Synchronising device for change speed gears - Google Patents

Abstract

780,155. Positive clutches. PORSCHE, F. Dec. 21, 1955 [Dec. 29, 1954], No. 36600/55. Class 80 (2). A synchronizing device for motor vehicle &c. change-speed gears, of the type in which the synchronizing means comprises a split spring ring, frictionally engageable by a tooothed clutch member and mounted on a supporting ring, is so formed that in one direction of rotation the servo assistance of the supporting ring assisting expansion of the split spring ring is rendered ineffective. As shown, a driven shaft 1 carries a member 4 on which an internally toothed clutch sleeve 5 can be slidden axially to engage with clutch teeth 10, 11 on hub members fast with pinions 2, 3 mounted for rotation about the shaft 1. Synchronizing split spring rings 15 are mounted on the hub members by supporting rings 17 having inwardly and outwardly extending projections 19, 18, engaging in slots 22 in each hub member and between the ends of the split ring 15, respectively. A small stud 23 in the hub member has a head 26 lying against the inner periphery of the supporting ring 17. When it is desired to' engage the sleeve 5 with the clutch teeth 10 from the neutral position shown, the vehicle being stationary and its engine idling, the main clutch is thrown out and movement of the gear lever initiated to engage lightly the teeth on the sleeve 5 with the outer friction surface of the split spring ring 15. Since the gears 2, 3, &c. will still be revolving at this moment, due to their inertia forces, this engagement tends to turn the split ring 15 in the direction of the arrow of Fig. 2 relative to the supporting hub 8, and by virtue of the projections 18, 19 the split ring then tends to turn the supporting ring 17 relatively to the hub member, so that it will take up an off-centre position with respect thereto and thereby wedge the split ring 15 apart into increased frictional engagement with the teeth on the sleeve 5. However, the head 26 of the stud 23 engaging the inner surface of the supporting ring 17 maintains the supporting ring substantially coaxial with its hub member, and thus prevents this servo assistance from becoming effective. The sleeve 5 can therefore readily be slidden over the split ring 15 to engage with the teeth 10 on synchronism. If the sleeve 5 is to be slidden axially out of engagement with the clutch teeth 11 and straight into engagement with the clutch teeth 10, the inertia forces to be overcome are substantially greater and the direction of relative rotation between the split ring 15 and the hub 8 is reversed, so that it is as shown in Fig. 3. In this direction of rotation, the stud 23 is ineffective and the supporting ring 17 wedges the split ring more firmly into engagement with the teeth on the sleeve 5, to give an increased synchronizing effect.