GB1590535A - Fluid machine - Google Patents

Description

PATENT SPECIFICATION

( 11) ( 21) Application No 7261/80 ( 22) Filed 23 June 1977 ( 19) _y ( 62) Divided Out of No 1,590,534 CM" ( 31) Convention Application No 7 619 341 ( 32) Filed 25 June 1976 in Ift ( 33) France (FR) A, ( 44) Complete Specification published 3 June 1981 t ( 51) INT CL F 04 B 1/04 21/02 F 03 C 1/04 -I ( 52) Index at acceptance F 1 W 108 201 506 EGA ( 54) FLUID MACHINE ( 71) I, JEAN-Luc PONCHAUX, of French nationality, residing at La Cure de Petosse, 85570 L'Hermenault, France, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following

statement:-

The present invention relates to a rotary machine, and more particularly, to a radial piston machine using fluid under pressure.

There are a number of examples of this type of machine which illustrate different constructions having cylinders, connecting means between the pistons and an eccentric, and the system for distributing the fluid to the piston and cylinder.

There are certain disadvantages which have been found in present day hydraulic machines For instance, it has been found that the distributor means associated with the machines have always been insufficient from the point of view of sealing, stability and long life As far as present rotating planar distributors are concerned, they are in principle subject to asymmetric forces which interfere with the functioning of the machine, limiting the performance thereof and provoking asymmetric wear and generating leaks and, therefore, lower output It has been possible to equilibrate these rotating planar distributors only by a complex number of parts, increasing, therefore, the costs.

It is an aim of the present invention to provide a simple machine which eliminates or mitigates the above-mentioned disadvantages.

The present invention provides a fluid machine comprising a housing, a shaft rotatably journaled in the housing and mounting an eccentric receiving a ring slidingly engaged thereon, a plurality of radial tubular pistons extending from the ring, each piston being mounted for sliding movement within a cylinder, each cylinder oscillating in the housing, a stator, slidingly engaged in the housing, centrally coaxial with the shaft and immobilized in the housing against rotational movement, connecting members between the ring and the housing for preventing the ring from turning with the eccentric and effecting a circular translational movement to the ring as the shaft rotates relatively to the housing, means for 55 allowing a continuous flow of fluid through the machine from an inlet port, through the cylinder-piston assemblies, to an outlet port, distributor means in association with the circular translational movement of the ring, 60 wherein said distributor meansincludes two main parts, one part being the stator which is adapted to slide axially in the housing and includes a radial planar face, with openings on this face, concentrically located about the 65 axis of the stator, said openings being twice as many as the number of cylinder-piston assemblies and comprising inlet and outlet openings, said inlet openings communicating with the inlet port of the machine, said outlet 70 openings communicating with the outlet port of the machine, said inlet and outlet openings being alternately arranged such that every said inlet opening is spaced by one said outlet opening, the other main part of 75 the said distributor means being the ring to which is fixed a plate having a radial planar face adapted to slidingly engage the radial planar face of the stator, slots defined in the face, the number of slots being equal to the 80 number of the cylinder-piston assemblies, each slot communicating with one cylinderpiston assembly through the ring, the said openings in the stator and said slots of the ring being arranged such that, when the shaft 85 rotates in the housing, every said slot, during its circular translational movement relative to the staotr, coincides alternately with one said inlet opening and one said outlet opening of the stator, which allows for the alternate 90 communication of the corresponding cylinderpiston assembly with the inlet port and the outlet port of the machine, and maintains the continuity of the fluid flow from the inlet port of the machine to the outlet port 95 A preferred embodiment of the invention is described below by way of example with reference to the accompanying drawings, in which:

Fig 1 is an axial section taken through a 100 typical hydraulic machine in accordance with the present invention; 1 590 535 2 1,590,535 Fig 2 is a radial cross-section taken along the line A-A of Fig 1; and Fig 3 is a fragmentary radial cross-section showing a further detail the embodiment of of Fig 1.

The embodiment shown in Fig 1 includes a hydraulic motor of the type having a rotating shaft and comprising a housing 1 and a shaft 2 mounted for rotation on bearings 3 in the housing 1 The housing 1 is closed at one end by a cover 4 having an aperture allowing the end 5 of the shaft 2 to protrude The other axial end of the housing is closed by a cover 6 which includes an inlet port 6 a and an outlet port 6 b The shaft 2 is cantilevered by the bearings 3 and includes a cylindrical eccentric portion 7 An annular ring 8, which includes a cylindrical bore, fits on the cylindrical eccentric and is concentric therewith The outer surface of the ring has a spherical shape.

The housing 1 has a number of radially extending bores 9 at right angles to the shaft 2.

In each of the cavities 9, there is an oscillating cylinder 10 having a cylindrical central bore which is adapted to receive in sliding relation a tubular piston 11.

A removable cover 15 closes the cavity 9 and is fixed thereto.

Each piston 11 includes a base part having a shoe 16 defined with a concave undersurface of spherical curvature matching with the convex spherical surface of the ring 8.

The pistons are retained against the surface of the ring 8 by means of anchor members 17 which are hook-shaped and engage the flange-like foot 16 of each piston 11 The anchors 17 are resiliently held against the foot 16 by means of springs 71 The ring 8 is retained against rotational movement with the eccentric 7 and its movement is controlled by connecting members mounted between the ring 8 and the housing 1, or between the ring and a part fixed to the housing.

For instance, as shown in Fig 3, the connecting members are in the form of cylindrical pins 45, located on the housing or on a plate part 47 fixed to the housing The pins 45 are spaced apart, concentrically located about the axis of the shaft 2 and they extend parallel to the axis of the shaft They mount abutment rings 44.

Also, pins 43 are fixed to the ring 8, spaced apart, concentrically located about the axis of the ring 8, and they extend beyond the margin of the ring 8, and are adapted to engage the abutment rings 44 The dimensions of the pins 43 and the abutment rings 44, as well as their relative spacing, is a function of the eccentric centre distance from the axis of the shaft.

In the embodiment shown in Fig 3 there are as many pins 43 as abutment rings 44 and each pin 43 has a corresponding pin 45 65 and abutment ring 44.

Finally, as the shaft 2 rotates,the ring 8, which is journalled on the eccentric 7, follows a circular locus, although the ring 8 does not rotate relative to the housing but 70 has a circular translational movement whose amplitude is relative to the distance travelled by the pistons 11.

The feeding of the hydraulic machine is provided by a planar distributor of which 75 the advantage will be made evident in the following description.

The annular ring 8 provides radial passages 28 each communicating with the bore of a tubular piston 11 80 Each radial passage 28 in the ring 8 is extended by a bore 59 which is parallel to the axis of the ring, and which communicates with a bore 60 defined in the plate 61 fixed to the ring 8 The plate 61 is generally in a radial 85 plane Each bore 60 communicates with a slot 62 defined in the plate 61, and opening on the outer surface of the plate 61 These slots 62 extend in a radial direction and are for instance five in number, that is, one for 90 each cylinder in this machine Each of the slots 62 is spaced an equal distance from each other and at the same distance from the centre of the plate 61 which coincides with the centre of the ring 8 95 The plate 61 which has an outer surface in a radial plane is adapted to slidingly engage the end surface also in a radial plane of a stepped cavity defined in the cover 6 adapted for axial sliding movement but held 100 against rotational movement.

A pushing member 64 slides in a cavity provided centrally along the axis of the stator 63 within the cover 6 The pushing member 64, along with the stator 63 and a 105 sleeve 65, define chambers 20 a, 20 b and c, each sealed one from the other by various 0-ring seal devices.

The chambers 20 a and 20 b are in communication with respective ports 6 a and 6 b 110 The chamber 20 c is in communication with the interior of the housing 1 of the machine by the intermediary of suitable passages.

Internally of the chamber 20 c, a coil spring 66 ensures the necessary pressure of the push 115 member 64 against the stator 63 and, therefore, the sealing pressure of the stator 63 against the outer face of the plate 61.

The stator 63 comprises passages 67 a and 67 b communicating respectively with the 120 chambers 20 a and 20 b to the openings 68 a and 68 b defined in the radial planar face of the stator 63.

According to the present embodiment as shown in, Figs 1 and 2, these openings, 125 represented by the numbers 68 a and 68 b, total ten, that is, twice as many the slots 62.

All of the openings 68 a and 68 b are concentrically'located about the axis of the stator 1,590,535 63 which is essentially the axis of the shaft 2 of the machine All of the openings 68 a and 68 b are equidistant and are alternated such that every opening 68 a is spaced by an opening 68 b.

Finally, as the shaft 2 rotates, the ring 8 and the plate 61 which is fixed thereto are journaled on the eccentric 7 and follow a circular locus, although the ring 8 and, the plate 61 do not rotate relative to the housing, but have a circular translational movement whose amplitude is relative to the distance travelled by the pistons 11 Means to maintain the ring 8 and plate 61 assembly in a circular translational movement, which are not represented on the Figs 1 and 2, may be of the type represented on the Fig 3 on any other type.

During the circular translational movement of the ring 8 and plate 61 relative to the stator 63, each of the slots 62 coincides alternatively with openings 68 a and 68 b which allows for the alternate communication of each cylinder 10 and piston 11 arrangement with the feed and exhaust ports 6 a and 6 b of the collector 6 as is clearly shown in Figs 1 and 2.

Accordingly, a planar distribution has been obtained in which the two parts of the distributor have a relative circular translational movement.

The radial dimensions of the chambers a and 20 b are determined by the pressure force acting on the stator 63 against the plate 61 to compensate exactly or to overcompensate the resultant force of the pressure field at the interface of the stator 63 and the plate 61.

In the case where an equal or exact compensation of the forces is obtained, the maintenance of the contact of the stator 63 against the external face of the plate 61 is ensured by the spring 66.

In the case of an overcompensation of these forces, the spring 66 can still be useful in order to ensure a contact between the stator 63 and the plate 61 when the hydraulic machine is inoperative.

In order to set up a hydrostatic system about the plate 61, an aperture 70 which is properly calibrated is adapted to communicate with a rear chamber 69 to allow some of this fluid to lead into this chamber.

In such a planar distributor, the balance of the axial loads, which tend to push the plate 61 against the radial end face of the eccentric 7, may be obtained, as represented on Fig 1, with a particular hydrostatic pad, disposed on the rear face of the plate 61 As represented, a rear chamber 69 has been disposed behind each slot 62 and communicates with through a properly calibrated aperture 70.

As the eccentric 7 rotates relative to the ring 8 and the plate 61, the interior face of the plate 61 presses against the radial end surface of the eccentric 7 and a field of pressure canbe established between these two surfaces as the machine is functioning with this new field of pressure being in equilibrium with the field of pressure established at the inter 70 face between the plate 61 and the stator 63 and permitting relative rotation of the planar faces between the plate 61 and the end of the eccentric 7 The axial forces applied against the eccentric 7 and the shaft 2 are absorbed 75 by the bearings 3 which have been selected accordingly.

The type of distributor described, that is, a planar distributor with relative rotational movement of translation between the parts 80 has the following advantages During the circular translational movement of the ring and the plate, the relative speeds of the opposite faces are everywhere equal There is, therefore, no risk of uneven wear in one 85 area compared to another, but on the contrary, there is a constant even wear which provides for longevity and proper functioning of the distribution system Since the relative speeds between the parts are low, the heat 90 generation is also kept low and the wear is kept at a minimum A good hydrostatic equilibrim is obtained between the parts of the distributor for reducing any tendency to buckle one relative to the other Again, this 95 reduces the risk of local uneven wear in one area as opposed to the other, and sealing is guaranteed no matter what the speed or the pressures of operation are in the machine.

All of these advantages allow the machine to 100 be operated at higher specific power than conventional machines, that is, higher speeds and higher pressure, without reducing the life of the machine or without interfering with the regularity of rotation when rotating at a 105 low speed.

It is obvious that the embodiment described with respect to Figs 1 and 2 is only given as an example and is not limiting For instance, the planar distributor having a 110 circular translational movement could be associated with machines having different designs than that described here.

To complete the description of the embodiment shown in Fig 1, it is noted that the 115 shoes of the piston are retained in contact against the ring 8 by means of a pair of anchors 17, in which the anchors are urged to resiliently hold the shoes of the piston by means of traction springs 71 which connect 120 the anchors.

The springs 71 are disposed circumferentially between the cylinders, and to avoid the springs abutting against the piston during the rotation of the machine, at least 125 one of the anchors 17 is fixed against rotation relative to the ring 8 For instance, in Fig 1, in the periphery of the plate 61, there is a radial notch 72 in which the loop of the spring 71 can be engaged The size of these 130 1,590,535 notches corresponds to the diameter of the wire used in fabricating the spring.

In certain situations, it would be useful to have access to the cottering of the distributor parts once the machine is completely assembled if only to be able to make a minor adjustment to compensate for different machining tolerances during the manufacture of the machine In such a case, it is possible to use the system shown schematically in the Fig 3 The pin 45 and abutment ring 44 assemblies are fixed to a plate 47 mounted in the housing in a radial plane, located essentially along the axis of the shaft 2.

This plate 47 includes an eccentric 51 which is accessible from the exterior of the machine, and which the eccentric part 52 engages in a notch 53 provided on the periphery of the plate 47 By pivoting the axis of the eccentric from the exterior of the machine, one can control the angular displacement of plate 47, thus effecting an angular displacement of the ring 8 and plate 61 relative the stator 63 by the intermediary of pins 45, of abutment rings 44 and abutting pins 43.

Accordingly, by this method, the cottering of the distribution system can be refined or improved depending on the operating conditions of the particular machine and its normal rate of rotation For instance, one can adjust for maximum cottering and have a good cyclical regularity at low speed in one direction of rotation On the other hand, if one wishes to have a perfectly reversible machine, it is best to arrange the distributor parts so that they are perfectly symmetrical, and thus can be done by the above-mentioned adjustments.

Accordingly, it is not necessary to readjust the distributor itself which only the manufacturer can do, but the user can make any necessary adjustments himself to adapt the hydraulic machine to its specific use.

Claims (3)

WHAT I CLAIM IS:-

1 A fluid machine comprising a housing, a shaft rotatably journaled in the housing and mounting an eccentric receiving a ring slidingly engaged thereon, a plurality of radial tubular pistons extending from the ring, each piston being mounted for sliding movement within a cylinder, each cylinder oscillating in the housing, a stator, slidingly engaged in the housing, centrally coaxial with the shaft and immobilized in the housing against rotational movement, connecting members between the ring and the housing for preventing the ring from turning with the eccentric and effecting a circular translational movement to the ring as the shaft rotates relatively to the housing, means for allowing a continuous flow of fluid through the machine from an inlet port, through the cylinder-piston assemblies, to an outlet port, distributor means in association with the circular translational movement of the ring, wherein said distributor means includes two main parts, one part being the stator which is adapted to slide axially in the housing and includes a radial planar face, with openings on this face, concentrically 70 located about the axis of the stator, said openings being twice as many as the number of cylinder-piston assemblies and comprising inlet and outlet openings, said inlet openings communicating with the inlet port of the 75 machine, said outlet openings communicating with the outlet port of the machine, said inlet and outlet openings being alternately arranged such that every said inlet opening is spaced by one said outlet opening, the 80 other main part of the said distributor means being the ring to which is fixed a plate having a radial planar face adapted to slidingly engage the radial planar face of the stator, slots defined in the face, the number of slots 85 being equal to the number of the cylinderpiston assemblies, each slot communicating with one cylinder-piston assembly through the ring, the said openings in the stator and said slots of the ring being arranged such 90 that, when the shaft rotates in the housing, every said slot, during its circular translational movement relative to the stator, coincides alternately with one said inlet opening and one said outlet opening of the 95 stator, which allows for the alternate communication of the corresponding cylinderpiston assembly with the inlet port and the outlet port of the machine, and maintains the continuity of the fluid flow from the inlet 100 port of the machine to the outlet port.

2 A machine as defined in claim 1, wherein the said connecting members are anchored to a plate disposed in a radial plane in the housing, concentrically with' the axis 105 of the shaft, and wherein an adjustment of the distribution can be effected from the exterior of the machine by means of an eccentric control journalled in the housing and having an axis parallel to the axis of the 110 shaft, the eccentric portion of the control adapted to engage a radial notch provided in the said plate such that rotational movement of the control from the exterior of the housing will cause a slight circumferential movement 115 of the ring relative to the stator through the plate and the said connecting members anchored to the plate, the eccentric control being then used to fix the plate in rotational position once the adjustment has been 120 effected.

3 A machine according to claim 1, substantially as described herein with reference to and as illustrated in the accompanying drawings 125 EDWARD EVANS & CO, Chancery House, 53-64 Chancery Lane, London, WC 2 A 15 D.

Agents for the Applicant.

Printed for Her Majesty's Stationery Office by Burgess & Son (Abingdon), Ltd -1981.

Published at The Patent Office, 25 Southampton Buildings, London, WC 2 A l AY, from which copies may be obtained.