WO1990003495A1

WO1990003495A1 - Positive vane control - rotary fluid pump/motor

Info

Publication number: WO1990003495A1
Application number: PCT/AU1989/000414
Authority: WO
Inventors: Leslie Mervyn Harrison
Original assignee: Leslie Mervyn Harrison
Priority date: 1988-09-23
Filing date: 1989-09-25
Publication date: 1990-04-05

Abstract

A conventional radial sliding vane type fluid pump or motor is characterised by cams non-rotatably supported in the housing (10), each cam, which is in the form of a cylindrical boss (25), having a bore (18) through which the shaft (16) of the rotor (15) passes. The cams engage the inner edges of the vanes (19) and are sized such that the radial clearance between the outer edge of each vane and the internal cylindrical surface of the housing is controlled by the cams to maintain a fluid tight seal. Also disclosed is a seal construction wherein an annular recess (26) provided in each housing end plate (27) receives a ring (31) fitted on an opposing end face of the rotor with running clearances therebetween which provide a restriction to fluid leakage between the opposed radial faces.

Description

POSITIVE VANE CONTROL - ROTARY FLUID PUMP/MOTOR

This invention relates to the improvement of radial vane movement control in rotary sliding vane fluid pump or motor. The efficiency of such motors or pumps depends to a large extent on the vanes maintaining a close relation with the internal cylindrical surface of the housing in which the rotor and vanes rotate. If the clearance between these components is not maintained fluid can pass between the adjacent chambers formed by the vanes, between the rotor and housing, resulting in performance loss and probable operating temperature increase.

Usually a portion of the operating fluid under pressure is directed to the under side or inner radial surfaces of the vanes, in an attempt to overcome this problem with varying degrees of success. Alternatively mechanical means such as springs have been used.

The object of this invention is to improve the sealing relation and maintain the correct working relationship between the vanes and the rotor and housing and to improve the efficiency and working life of the pump or motor.

With this object in view there is provided a radial vane fluid pump or motor comprising a housing having a cylindrical bore, a rotor mounted in the cylindrical bore to rotate about an axis parallel to and eccentric to the axis of the bore, a plurality of vanes supported in the housing or rotor for radial movement relative to one and operatively related to the other to form a seal therewith thereby defining a plurality of chambers that each vary in volume as a result of relative rotation between the housing and rotor, and wherein the other of the housing and rotor includes guide means to operatively co-operate with the vanes to control the radial movement thereof to maintain the required radial clearance between the ends of the vanes and the stationary housing or rotor. Conveniently the rotor rotates relative to the housing with the vanes radially slidable in the rotor and the guide means are supported by the housing. Preferably the guide means co-operate with a radial inner portion of the vanes.

In accordance with another aspect of the present invention there is provided a radial vane fluid pump or motor comprising a housing having a cylindrical bore, a rotor mounted in the cylindrical bore to rotate about an axis parallel to and eccentric to the axis of the bore, a plurality of vanes supported in the housing or rotor for radial movement relative to one and operatively related to the other to form a seal therewith thereby defining a plurality of chambers that each vary in volume as a result of relative rotation between the housing and rotor, and an annular seal ring co-axial with the axis of rotation and secured to one of the rotor or housing and an annular recess in the other of said rotor and housing, said seal ring extending into said recess in a close running fit thereto to restrict fluid flow between opposed radial faces of the rotor and housing.

The invention will be more readily understood from the following description of various embodiments of vane type pumps or motors as illustrated in the accompanying drawings.

Figure 1 is an exploded axial cross-sectional view of a pump or motor.

Figure 2 is a sectional view of the rotor. Figure 3 is a sectional view along line 3-3 in Figure 1.

Figure 4 is an exploded axial cross-sectional view similar to Figure 1 showing the end face seal.

Figure 5 is a sectional view along line 5-5 in

Figure 4. Referring now to Figures 1, 2 and 3, the pump or motor comprises a housing 10 having a pair of end plates 12 and cylindrical wall 14. The rotor 15 has integral shaft sections 16 and either end rotatably received in bores 18 in the end plates 12. The shaft sections 16 are concentric to the external cylindrical surface 21 of the rotor 15 and the bores 18 are coaxial to the internal cylindrical surface 23 of the wall 14 of the housing 10.

The rotor 15 has four equally spaced radial slots 13 that extend the full axial length of the rotor 19. Slidably supported in each radial slot 13 is a vane 12. Each vane extends the length of the rotor and has a radial dimension greater than the eccentricity of the rotor to the housing plus the minimum clearance between the rotor and housing. Suitable inlet and exhaust ports are provided in the housing to successively communicate with the chamber formed between the vane. The above described pump or motor construction is conventional and is for the purpose of describing the general construction of the pump or motor to which the invention may be applied.

Each end plate 12 has a boss 25 formed integral therewith or attached thereto projecting inwardly of the housing 10. The boss is of cylindrical form and eccentric to the bore 18 by the same extent as the rotor is eccentric to the bore 18.

Each axial end of the rotor 15 has a cylindrical cavity 17 coaxial with the shafts 16 and of a diameter equal twice the maximum radial distance of the boss 25 from the axis of the bore 18. The radial extend of the vanes 19 is such at the radially inner face of the vanes will always project into the cavity 17 in all rotational positions of the vane. The diameter of the boss 25 is equal to the internal diameter of the housing 10 less twice the radial extent of the vanes 19 less also the required radial working clearance of the vanes in the housing.

In operation the boss 25 is received in the cavity 17 and the end portions radially inner faces of the vanes bear on the cylindrical surface of the boss 25. This construction ensures that the radial clearance between the outer edges of the vanes and the inner face of the housing wall does not exceed that set by the eccentric boss 25. In the construction shown in Figures 4 and 5 there is described new seal construction between the opposed end faces of the housing and rotor which may be incorporated in the pump or motor as previously described or independently in other forms of vane pumps or motors.

Referring to Figures 4 and 5, a recess 26 is provided in the internal face of the each of the end plate 27 concentric with the bore 28. On opposing end faces 29 of the rotor 30 are rings 31 coaxial with the rotor shaft 32. When the rotor and housing are in operating assembly with the shaft 32 in the bore 28 the rings 31 are received in the recesses 26 with running clearance therebetween in both the radial and axial directions. This provides a substantial restriction to the leakage of fluid between adjacent chambers of the pump and motor and between each chamber and atmosphere via the bore in which the rotor shaft is supported.

In an alternative construction the ring may be of a greater radial extent and extend to the shaft 32 as seen in Figure 5. In such a construction the recess 26 will extend to the bore 28. In each of the above constructions the ring may be separate from the rotor and attached thereto or integral with the rotor. The constructional features of the fluid pump and motor described herein particularly assist in start-up and low to medium speed operation, particular at speed when centrifugal force is not sufficient to effectively maintain a seal between the vanes and the housing. The construction is particularly applicable to pneumatic pumps and motor.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS;

1. A radial vane fluid pump or motor comprising a housing having a cylindrical bore, a rotor mounted in the cylindrical bore to rotate about an axis parallel to and eccentric to the axis of the bore, a plurality of vanes supported in the housing or rotor for radial movement relative to one and operatively related to the other to form a seal therewith thereby defining a plurality of chambers that each vary in volume as a result of relative rotation between the housing and rotor, and wherein the other of the housing and rotor includes guide means to operatively co-operate with the vanes to control the radial movement thereof to maintain the required radial clearance between the ends of the vanes and the stationary housing or rotor.

2. A radial vane pump or motor as claimed in claim 1 wherein the rotor rotates relative to the housing with the vanes radially slidable in the rotor and the guide means are supported by the housing.

3. A radial vane pump or motor as claimed in claim 1 or 2 wherein the guide means co-operate with a radial inner portion of the vanes.

4. A radial vane pump or motor as claimed in any one of claims 1 to 3 wherein the guide means is a cam with a circular cam profile mounted eccentric to the axis of rotation of the rotor by an amount equal to the eccentricity of the rotor, said vanes engaging the profile of the cam.

5. A radial vane pump or motor as claimed in claim 4 wherein the cam is received to a cavity in the rotor coaxial with the rotor, said vane projecting into said cavity to engage the profile of the cam.

6. A radial vane pump or motor as claimed in any one of the preceding claims wherein an annular seal ring co-axial with the axis of rotation and secured to one of the rotor or housing and an annular recess in the other of said rotor and housing, said seal ring extending into said recess in a close running fit thereto to restrict fluid flow between opposed radial faces of the rotor and housing.

7. A radial vane fluid pump or motor comprising a housing having a radial vane fluid pump or motor comprising a housing having a cylindrical bore, a rotor mounted in the cylindrical bore to 'rotate about an axis parallel to and eccentric to the axis of the bore, a plurality of vanes supported in the housing or rotor for radial movement relative to one and operatively related to the other to form a seal therewith thereby defining a plurality of chambers that each vary in volume as a result of relative rotation between the housing and rotor, and an annular seal ring co-axial with the axis of rotation and secured to one of the rotor or housing and an annular recess in the other of said rotor and housing, said seal ring extending into said recess in a close running fit thereto to restrict fluid flow between opposed radial faces of the rotor and housing.

8. A radial vane fluid pump or motor as claimed in claim 6 or 7 wherein the seal ring extends to the surface of a shaft that supports the rotor in a bore in the housing and the recess extends to said bore.