GB1256990A - - Google Patents

Abstract

1,256,990. Differential gearing. THORNTON PRODUCTS CO. 6 Nov., 1970, No. 52836/70. Heading F2D. In a motor-vehicle self-locking bevel differential gear, excessive slip is resisted by a multiplate friction clutch 52 arranged between a side-wheel 44 and the bevel planet carrier 26 and engaged by pressure fluid in a pressure chamber 90 supplied by a piston type pump 63 located within the planet carrier pinion spider 48, the pump piston 78 being arranged in a radial bore 76 of a pump rotor 74, which is drivingly connected with the other side wheel 46, the outer end 80 of the pump piston engaging an eccentric cam 84 in the spider 48 such that the pump piston 78 is reciprocated in its radial bore 76 by relative rotation between the side wheel 46 and planet carrier spider 48 to pump fluid via spring-loaded non-return suction and delivery valves 86, 88 from a fluid source at the inlet end 72 of the pump 63 to the pressure chamber 90. During normal differential action, i.e. slow relative turning of the pump rotor 74 with respect to the spider, a controlled leakage from the pressure chamber 90 i.e. a clearance between a sealing ring 94 and the spider 48, prevents any pressure build up therein and the clutch remains disengaged to permit unrestrained differential action. Should undesirable slippage of one wheel occur, the pumping action will be at a greater rate causing a pressure fluid build up in chamber 90 which via a piston 92 axially moves the side wheel 44 and a pressure plate 54, both slidably splined on a half shaft 22, to engage the clutch 52 to lock the differential, such locking action being quickly and smoothly released as soon as the wheel slippage ceases by virtue of the controlled leakage permitted at 94 from the pressure chamber 90. An adjustable spring loaded accumulator 98 is provided to stabilize the fluid pressure generated by the pump 63 i.e. smooth out the action of the pump, and an adjustable pressure limiting ball relief valve 110 controls the operating pressure of the fluid both valves being connected to the pressure chamber 90 by ducts 103 and 102, 112 respectively. The fluid source at the inlet end of the pump 63 is maintained by an auxiliary pump 128 arranged in a fixed eccentric chamber 130 directly below an oil scoop 122 which collects lubricant from the crown wheel 120 and directs it via a funnel 126 and holes 136 into the chamber 130, a pair of flexible vanes 132, 134 connected to the planet carrier case 26 oscillating within the fixed eccentric chamber 130 to pump the collected lubricant via one-way reed valves 140 and ducts 152, 66 into the inlet end of the piston pump assembly 63, a flexible plate pressure relief valve 144 being arranged to bow outwardly to relieve excess internal pressure within the eccentric housing 130 via ports 150.