GB663466A - Hydraulic variable speed gear - Google Patents

Abstract

663,466. Hydraulic transmission of power ; liquidpressure engines. VILLIERS, C. P. R. DE. Nov. 23, 1948 [Dec. 15, 1947], No. 30455/48. Class 69 (ii) [Also in Group XXVIII] In a hydraulic variable-speed gear comprising power input and output shafts 3 and 26, respectively, operatively connected together through two hydraulic machines, such as pump A and motor B, each of the type having radial pistons 13 working in a rotary cylinder block 1 wherein the annulus 2 of one of the machines, for example the pump A, is fixed to the power input shaft 3 and the cylinder block 2 within it is mounted on an eccentric ported shaft 4, there is provided an annulus 27 enclosing the cylinder block of the other machine B which is fixed on the output shaft 26. The annulus 2, which is integral with an engine fly-wheel, and cylinder block 1 of the pump A are coupled to the input shaft 3 whilst the block 1 is rotatably mounted upon an eccentric 10 formed on the ported shaft 4, the latter being aligned with shaft 3. Radial cylinders 11 in the block 1 have pistons 13 therein the rods of which coact with the annulus 2, the block 1 being coupled to the flywheel by a self-adjusting coupling 12 as described in Specification No. 542,733. The shaft 4 is connected by an intermediate shaft 25 to the output shaft 26, and the motor B is disposed around shaft 25, the annulus 27 of which motor is connected to shaft 26, whilst its cylinder block 28 is rotatably mounted upon a non-rotatable pintle 29 whose eccentricity is adjustable by two cylinders 30 and 31 fixed to the casing 32, the pistons in which are part of the pintle 29. Port 16 in shaft 4 communicates with low-pressure conduit 17 through ports 18, 19 and 20, and another port in shaft 4 communicates with high-pressure conduit 22 via ports 24. Dynamic balance is obtained by attaching weights 34 to shaft 4, and hydrostatic balance of shaft 4 is effected by grooves 35, one being arranged peripherally on the same side as the high-pressure port but communicating with the low-pressure port, and the other groove being oppositely arranged and communicating with the high-pressure port. Noise may be reduced by small orifices near the edges of the ports in shaft 4 which establish restricted communication between each port and the respective cylinder before that cylinder and port are directly connected. A spring-loaded valve 36 which permits of short-circuiting the oil circulation to pump A, performs the function of a clutch. The displacement of motor B is preferably three times that of pump A so that when pintle 29 is at maximum eccentricity in one direction the torque of motor B is a maximum and approximately three times that of pump A and the torque passed to the shaft 26 is four times engine torque. When the pintle 29 is adjusted to zero eccentricity there is a direct drive between shafts 3 and 26 but when the pintle is adjusted to an eccentric position in the other direction, motor B acts as a pump and drives machine A as a motor so that shaft 4 is driven faster than shaft 3. Specification 553,210 also is referred to. The Specification as open to inspection under Sect. 91, comprises also a modification in which the shaft 4 forms an extension of shaft 3 whilst cylinder block 1 and annulus 2 are coupled to shaft 26. This subject-matter does not appear in the Specification as accepted.