Patent GB-790035-A (GB)
Title: Pump and lock for differential
IPC: F16H39/00
Filed: 1956-01-17
Abstract: 790,035. Centrifugal and rotary pumps. MUELLER, O. Jan. 17, 1956 [Nov. 21, 1955], No. 1614/56. Classes 110 (1) and 110 (2). [Also in Groups XXIV and XXXIV] A differential comprises a housing with oil therein, a case within the housing and differential means within the case, the case having at least one passageway for scooping up oil from the housing and delivering it to the interior of the case. In one form, Fig. 1, a driving casing 10 supports bevel planet gears engaging sun gears on shaft 13, 23. The casing 10 rotates in a stationary housing (not shown), containing oil, which is pumped into the differential gearing through scoop-type conduits 48, 49, Fig. 3, when the vehicle is driven forwardly. The hub 24 of one of the sun gears is in driving connection with the rotor 26 of a fluid locking device 22 operative to prevent excessive relative rotation between the half-shafts 13, 23. The rotor 26 carries radially directed vanes 28, Fig. 2, biased outwardly by springs 31 to engage with an elliptically-shaped orifice in a ring 21 rotationally fast with the casing 10. Pins 36 in the ring 21 engage arcuate recesses 35 in a plate 32 relatively rotatable on the gear hub 24 an amount determined by the length of the arcuate recesses. The plate 32 contains inlet orifices 33, through which oil is drawn from the differential gearing into the body of the pump, and outlet orifices 45. The lost-motion connection between the plate 32 and the casing 10 ensures that the inlet orifices 33 shall be correctly placed relatively to the compression portion of the pump working space, irrespective of the relative directions of rotation between the hub 24 and casing 10. The outlet orifices 45 communicate with an orifice 46 in an annular piston 37 normally biased to frictionally engage the ring 32 by an elastic seal 43. Relative rotation between the shafts 13, 23, .as when a wheel of the vehicle spins on soft ground, causes the two parts of the pump to turn relatively to each other, so that oil under pressure is supplied through the outlet conduit 45 and through the conduit 46 to the back 38 of the annular piston 37, which is thereby forced rightwards of Fig. 1, to reduce leakage from the parts to a minimum. The space at the back of the annular piston 37 communicates through a conduit 40, Fig. 4, with a by-pass ball valve 50 which returns the oil to the differential casing through a passageway 30. In a modification in which it is desired that lubricant shall be pumped from the stationary housing into the rotating casing when the vehicle moves backwards as well as forwards, a ring 57, Figs. 5, 7, has a rotational lost-motion connection with a casing part 55 by means of pins 63 engaging arcuate recesses 62. Conduits 64, 65 in the ring 57 are arranged to pump oil into the differential gearing in the two directions of rotation. In one direction of rotation, the ring 57 turns as far as its pin-andslot lost-motion connection with the main casing part 55 will allow, to the position shown in Fig. 7. The conduits 65 then communicate with conduits 67 in the casing part 55, so that oil can then be supplied through ports 68 to the differential gearing. In this position of the ring 57, the conduits 64 are closed. On reversing the direction of rotation of the vehicle, the ring 57 turns relatively to the casing 55 and the conduits 64 then communicate with conduits 66 in the casing part 57, through which lubricating oil is then supplied. The conduits 65 are then closed. In another modification, a two-speed differential comprising gears 71, 72, Fig. 9, is provided with lubricating means formed by a ring 117 having a lost-motion connection with a casing part 73. A pin 121, Fig. 12, in the casing 73 engages either a block 122 or a stop 126 on the ring 117, according to the direction of rotation. Two similar passages 118, 119 are formed side-by-side in the ring 117, each communicating with the oil in the surrounding stationary housing by means of holes 123. In the position shown in Fig. 12, the ring 117 has turned to a position in which the passageway 118 communicates with a conduit 125 so that oil can be pumped into the gears of the differential. If the direction of rotation of the casing 73 is reversed, the ring 117 turns on the casing so that the stop 126 abuts the pin 121. Accordingly the conduit 125 is closed, but simultaneously, a corresponding conduit is opened so that the passage 119 can supply oil to the gears. A fluid lock, comprised by a rotary pump between a sun gear 78 and the gear 72, having radially-movable vanes and of generally similar construction to that described with respect to Fig. 2, draws lubricating oil from the gears through conduits 92 and passes it through pressure release valves to return via conduits 107 when excessive rotation occurs between half-shafts 82. The sun gears of the differential are forced apart by a compression ring 136 of Neoprene so that the various moving surfaces of the pump are forced into sealing engagement.