Patent GB-715445-A (GB)
Title: Differential mechanism
IPC: B60K17/348
Filed: 1952-10-02
Abstract: 715,445. Differential gear. PATENT DEVELOPERS, Inc. Oct. 2, 1952 [Oct. 10. 1951], No. 24686/52. Class 80 (2) Relates to a differential gear distributing drive between the multi-axles of a motorvehicle, permitting overrun of either or of only one of the two driven shafts 47, 48, and comprising facially toothed clutches 63, 64 between a centre driving element 49 fast in a driving casing 42 and each of two driven elements 52, 53 splined, through sleeves 56, to the driven shafts 47, 48, and moved axially outwards, against springs 58, to disengage either dutch 63 when the corresponding driven shaft 47 or 48 overruns, by inclined facial camming teeth 67 on the driven elements 52, 53 meshing similar teeth 68 on opposite faces of a freely rotatable but axially immovable inner cam member 50, the clutch teeth 63, 64 having sufficient circumferential clearance to permit such movement. In such a gear intermittent clutch-tooth contact on overrun is prevented by hold-out sleeves 54, 55 which, on overrun, are frictionally dragged to .make a limited turn with respect to either the driven or cam members to interpose a stop in the path of the declutched overrunning driven element, prevent its axial clutch-engaging return until overrun ceases, whereupon the hold-out sleeve is frictionally dragged back out of balk position and the clutch re-engages. In Figs. 3 and 11 each hold-out sleeve 54 is frictionally mounted on an inner part 66 of its driven element 52 through a polygonally-formed bladespring 80 which also prevents relative axial movement of the hold-out sleeve. Six spaced axial projections 79 on each hold-out sleeve 54 permanently engage with limited circumferentiall movement in slots 85, Fig. 11, formed by cutting away pairs of adjacent teeth 68 of the inner cam member 50 through the axial centres of the bounding teeth 86. When, due to overrun, the camming teeth 67, 68 move a driven element 52 axially outwards to disengage the clutch teeth 63, 64, the corresponding hold-out sleeve 54 is frictionally dragged to the limit of the slots 85 so that steps 83 at the roots of the hold-out sleeve projections 79 abut the endfaces of the adjacent part-teeth 86 of the cam member 50 (position shown) thus preventing return axial clutch-engagement movement of the driven member 52. This condition persists until cessation of overrun drags back the hold-out sleeve 54 to release the driven clutch element 52 for re-engagement under spring load In Figs. 17-21 (not shown), the inner cam member, e.g. 50, Fig. 3. has a single axial tooth projecting on each side into a split in each hold-out sleeve which has cam teeth maintained in end-to-end butting relation with the cam teeth of the inner cam member 50 during overrun. In Figs. 22-25, not shown, the single tooth is on the hold-out sleeve and the slot in the inner cam member In Figs. 26-30, not shown. the cam- and clutch-teeth, e.g. 64, 67, Fig. 3, are continuous in the same radial plane and the driven elements, e.g. 52, (or hold-out sleeves) carry single teeth engaging splits in hold-out sleeves (or driven elements) frictionally mounted on the inner cam member, e.g. 50, and having facial balk-teeth similar to the cam teeth and in the same radial plane. If the gear is required to distribute drive between front and rear axles and the arrangement is to be such that the front axle causes drive of dts shaft 47 at a slightly higher speed than that, 48, of the rear axles so that unless the rear wheels are actually losing traction the front axle is always overrunning, the overrun action of the rear-axle drive shaft 48 is permanently and positively prevented either by butting the driving-casing wall directly against the corresponding driven element 53 or additionally by eliminating the camming. hold-out and spring elements corresponding to that driven element. Specifications 560.648 561,350, and U.S.A Specification 2,638,794 are referred to.