US3196801A

US3196801A - Fluid pumps or motors

Info

Publication number: US3196801A
Application number: US311358A
Authority: US
Inventors: Ifield Richard Joseph
Original assignee: Lucas Industries Ltd
Current assignee: ZF International UK Ltd
Priority date: 1962-10-11
Filing date: 1963-09-25
Publication date: 1965-07-27
Anticipated expiration: 1982-07-27
Also published as: DE1453561A1

Description

@mf f July 27, 1965 R. J. lFn-:LD 3,196,801

FLUID PUMPS OR MOTORS Filed Sept. 25, 1963 United States Patent O 3,196,31 EUUED PUMPS GR MGTGRS Richard Joseph lield, Beecrott, New South Wales, Australia, assigner' to Joseph Lucas (Industries) Limited, `Birmingham, Engiand Filed Sept. 2S, 1963, Ser. No. 311,358 Claims priority, application Great Britain, ct. 11, 1962, 38,602/62 1 Claim. (Cl. 10S- 162) This invention relates to fluid pumps or motors of the reciprocatory piston type and comprising a hollow body, a cylinder barrel rotatable within the body, a plurality of angularly spaced longitudinal bores Within the barrel, a plurality of spherical headed pistons occupying the bores respectively, a rotatable carrier within the body, means connecting the pistons to the carrier at angularly spaced points respectively, and means for varying the angle between the axes of the carrier and barrel respectively the arrangement being since that as the carrier and barrel are rotated reciprocatory movement will be imparted t the pistons.

With such pumps or motors ditiiculty has arisen in providing an elicient seal between the pistons and the bores and the object of this invention is to minimise this diliiculty in a simple and convenient manner.

According to the invention in a fluid pump or motor of the kind speciied each piston is provided with a resilient sealing ring located in a groove in the periphery of the piston, the groove being so positioned in relation to the spherical centre of the piston that the line of contact of the sealing ring and the wall of the bore lies wholly in front or wholly behind the line of contact of the piston nad the wall of the bore during the operation of the pump or motor.

in the accompanying drawings- FIGURE 1 is a section View of one example of a hydraulic pump embodying the invention and M FGURE 2 is an enlarged View of a part of the pump shown in FGURE l.

Referring to the drawings there is provided a multipart body constituted by a hollow main body 1 of stepped cylindrical form and a cover 1a closing the Wider end of the body. Extending into the wider part of the body is a rotatable shaft 2 which at one end is adapted for connection to an engine and at its other end is drivingly engaged with a rotary carrier 3 which is supported in anti-friction bearings 4 in the body.

Within the body is mounted a port-block 5 which has a flat face 6 presented towards the carrier and an opposite face 7 of part cylindrical form, whereby the block may be tilted, wlL'ch bears against .a complementary surface formed on the cover. Moreover rotation of the portblock is prevented by the abutment of cheeks S formed on the cover with complementary surfaces (not shown) formed on the port-block.

Mounted on the dat face of the port block is a spigot 1@ upon which is rotatably mounted, by means of an anti-friction bearing 12, a rotary cylinder barrel 11. The cylinder barrel is in driving engagement with the carrier by means of a universally jointed coupling 13 which is held in position by a thrust-pad 14 loaded by springs 9.

Formed in the cylinder barrel are a plurality of equiangularly -spaced cylinders 15 which are extended to ddgdhl Patented July 27, 1965 form ports 16 adjacent the port-block. Within the cylinders are mounted a plurality of pistons 17 respectively which are provided with piston rods terminating in spherical ends 2S which are engaged in equi-angularly spaced spherical seatings in the carrier 3.

ln the flat face of the port bloclr are formed an arcuate inlet port 2@ and an arcuate outlet port with which thc ends of the cylinders register in turn as the cylinder barrel rotates. The arcuate inlet and outlet ports are connected respectively through passages 24 extending through the port block to an inlet 22 and outlet 23 -in the cover whereby hydraulic liquid can be admitted t0 and discharged from the cylinders.

Thus, when the dat face of the port block is inclined relative to the shaft axis and the latter is rotated, the pistons are reciprocated. Hydraulic liquid is thus drawn into the cylinders while they are in communication with the inlet port and discharged when they are in communication with the outlet port.

L The parts of the piston 17 which contacts the wall of the cylinder is of spherical form so that line Contact, indicated by the dotted line 27' in FIGURE 2, is always maintained between the piston and the wall. In order to provide a liuid seal between the piston and the wall of the bore a peripheral groove 26 is provided on the piston and in the groove is located a sealing ring 28. The groove is so disposed in relation to the spherical centre ot the piston that the line of contact of the sealing ring and the wall of the bore lies wholly in front of the line of contat of the piston and the wall of the bore during the operation of the pump.

By a construction of pump as above described the sealing ring is relieved of loads due to centrifugal force acting on the piston and is thus better able to perform its sealing function. However the wear on the sealing ring is reduced.

lt will be appreciated that the groove 26 could be formed in the piston so that the sealing ring lies wholly behind the line of contact 0f the piston and cylinder during operation of the pump.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

Hydraulic apparatus comprising in combination a hollow body, a cylinder barrel rotatably mounted within the body, a rotatable carrier mounted within the body, means for varying the angle between the axis of the barrel and carrier respectively, a plurality of longitudinal cylinders formed in the barrel, a plurality of spherical headed pistons occupying the cylinders respectively, means connecting the piston to the carrier at angularly spaced points respectively, a plurality of grooves formed in the periphery of the pistons respectively at points removed from the lines of contact of the pistons and the cylinders and a plurality of resilient sealing rings occupying the grooves respectively.

Reterences Cited by the Examiner UNITED STATES PATENTS 2,792,790 5/57 Capps 103-178 2,956,508 l0/ 60 Wahlmark 103-162 2,956,845 10/60 Wahlmark 10B-162 LAURENCE V. EFNER, Primary Examiner.