GB543819A - Improvements in and relating to power transmissions - Google Patents

Abstract

543,819. Reciprocating pumps for liquids. ARMSTRONG, J. J. V. (Vickers, H. F.). March 28, 1941, No. 4169. [Class 102 (i)] [Also in Group XXIX] In a hydraulic transmission device of tne kind comprising a pump and a motor of the reciprocating piston and rotary valve type an auxiliary bearing surface is provided in connection with the valve which controls the flow of fluid to or from the cylinders of the pistons 24 which are actuated by an adjustable swashplate device. As shown, the pump cylinder barrel 44 is mounted in a yoke 32 adjustable about trunnions 38 forming part of the fluid inlet and outlet, and the barrel is driven from a shaft 16 by means of a rod 52 connected by universal joints 54 to a socket flange 18 and to the barrel the flange being fitted with ball sockets 20 for receiving connecting-rods 22 attached to the pistons 24. The barrel 44 has outlets 50 which register with a pair of segmental inlet and outlet grooves 48 in the valve plate 34 forming part of the yoke 32. The barrel is pressed by a spring plunger into contact with the valve and the structure is designed to constitute a hydraulic balance. To prevent errors due to inaccurate machining which would upset this balance an auxiliary bearing is provided between the face 40 ot the valve and the face of the barrel 44 having the form of a number of segmental pads 56 let into the valve face and formed with depressed parts or chambers 58 forming liquid receiving chambers which are supplied with fluid by a metering device comprising a chamber 70 connected by passages 72, 74, 62, 60 to the chambers 58 and supplied with fluid by a valve 78 controlled by a spring piston 80 connected at one end by a passage 88 to the end of the restrictor passage 72 and at the other end by a passage 86 to the chamber 70. A constant pressure drop is maintained across the restrictor 72 and oil is delivered at a constant minute rate to the chambers 58. The oil has to escape between the surfaces of the valve and barrel and so ensures a constant slight clearance between them which can be adjusted to ensure a hydraulic balance which is restored automatically if upset. The chambers 58 may be fed individually by separate devices, and the invention may balance thrusts in other situations, e.g. between the flange 18 and the thrust bearings 14. The invention may be applied in reversible machines where either port 30 may be the pressure port. Specification 538,746 is referred to.