WO1994018434A1

WO1994018434A1 - Fluid displacement apparatus

Info

Publication number: WO1994018434A1
Application number: PCT/AU1993/000065
Authority: WO
Inventors: John Joseph Davies
Original assignee: John Joseph Davies
Priority date: 1993-02-15
Filing date: 1993-02-15
Publication date: 1994-08-18
Also published as: AU3486893A

Abstract

A fluid displacement apparatus comprising a housing (51) having a spherical inner surface (17), within which is mounted a body member (10) having in its outer surface a pair of recesses (11, 12). A pair of piston members (13, 14) rotatably mounted to the housing (51) each include a piston portion (15) slidably engaged with its respective recess (11, 12) to define working chambers of varying volumes upon rotation. A pair of ports (70) connect the working chambers cyclically with a fluid inlet and a fluid outlet.

Description

"FLUID DISPLACEMENT AP7^*'*ATUS" This invention relates to fluid c placement apparatus. In particular, this invention relates to fluid displacement apparatus which make use of rotary mechanical energy for providing positive displacement such as a fluid pump, and for illustrative purposes this invention will be described hereinafter with reference to this application. However, this invention may find practical use in other applications such as a fluid engine adapted to use the energy of an energetic fluid to do mechanical work. At present pumps internal combustion engines and the like, hereinafter collectively referred to as engines, mostly utilise reciprocating parts to use or effect positive fluid displacement to translate to or from a rotary mechanical motion. Alternatively, such positive fluid displacement may be provided by rotation of one part in another, enmeshing of complementary shaped parts, or orbital motion of one part in another.

For example, hydraulic vane apparatus such as that disclosed in USSR Patent Specification No. SU-A-819363, comprises a housing accommodating a rotor having a cam-shaped end face and a shaft. The housing has slots receiving radially extending vanes mounted for axial movement under the action of springs. During rotation of the rotor by a drive motor, the vanes which are permanently pressed against the cam end face of the rotor reciprocate to ensure regular variation of capacity of pressure and suction working chambers The vanes divide these chambers, and the volumetric efficiency, which is the ratio of the volume of utilized fluid to the maximum volume of the working chamber, depends on quality of sealing between the end faces of the vanes and the cam end face of the rotor. It is difficult to provide an efficient sealing member of the narrow end face of the vane. Accordingly, the volumetric efficiency of the machine is rather low. USSR Patent Specification No. SU-A-877129 discloses a rotary displacement pump having a housing with an inner spherical surface mating with the outer surface of vanes having power take off shafts provided thereon to extend along their axes of symmetry at an angle with respect to each other. There is also provided a partition extending in the diametrical plane having its outer surface mating with the inner surface of the housing. Vane supports and a sealing member received in a groove are provided in the diametrical plane of the partition.

The apparatus disclosed has an increased volumetric efficiency relative to that disclosed in USSR Patent Specification No. SU-A-819363 because of an increase in the useful volume of the working chambers with the same inside diameter of the housing. However, the provision of a sealing member that takes a part of the useful space of the working chambers lowers the possibility of increasing the volumetric efficiency. In addition, the sealing line in the diametrical plane is long and very sinuous so that is very difficult to ensure a reliable sealing.

The present invention aims to substantially alleviate at least some of the above disadvantages of the prior art apparatus and to provide fluid displacement apparatus which is reliable and efficient in use. Other objects and advantages of the present invention will hereinafter become apparent.

With the foregoing and other advantages in view, this invention in one aspect resides broadly in fluid displacement apparatus including:- a housing defining a substantially spherical chamber; a pair of piston members having outer faces sealably engaged with the inner surface of said chamber and being mounted for rotation about respective axes each passing through the spherical centre of said housing; a body member having outer extremities sealably engaged with the surface of said chamber and respective elongate recesses to receive said piston members for sliding periodic movement rotationally coupling said piston members, and porting provided through said housing and being in periodic communication with end regions of said recesses.

The body member may include a pair of orthogonal, part annular recesses each adapted to be engaged by a piston member and adapted to define therewith a chamber which may be varied in volume by movement of the piston member along the recess. Preferably, the recesses extend annularly for the maximum extent without intersecting. Alternatively, the body member may include a pair of orthogonal recesses each extending circumferentially about the body member, and wherein a piston member is disposed within each recess, the pistons each including side wall portions adapted to close an end of the other recess.

The piston members are preferably provided with a bearing surface adapted to engage the inner wall of the recesses. For example, in the embodiments of the invention having intersecting recesses and where the side walls of the piston in a first recess serve to close the ends of the other recess, the inner wall of the recesses preferably comprises a common substantially spherical inner wall, and each of the pistons bears upon the spherical surface of the inner wall on a complementary part spherical bearing surface.

Alternatively, in the case of a body member having a pair of non intersecting recesses, it is preferred that each of the recesses has a substantially part cylindrical inner wall, which is easier to form or machine to a better bearing surface, with each of the pistons having a complementary part cylindrical bearing surface adapted to bear upon its respective inner wall. The opposed side walls of the recesses may advantageously diverge radially from said inner wall in extending to the outer peripheral bounds of the recess, in order to take advantage of the increasing volume of the sphere described by the body member and thereby increase the swept volume of the pistons. Preferably, the opposed walls diverge at an included angle of 90° to maximize the total recess volume over the two recesses.

The piston members may advantageously be mounted for rotation relative to the housing by provision of a shaft portion mounted for rotation in a bearing provided in the housing. By virtue of the operation of the apparatus in both pump and motor applications, it may be desirable to have one of the shaft portions extending out of the housing, providing means whereby the apparatus may be coupled to a drive for pumping or to a load for doing work. Alternatively, both shafts may pass through the housing.

Preferably, the body member is sealed for sliding movement against the inner surface of the housing via sealing means. For example, the sealing means may comprise a sealing member disposed about the outer periphery of the recess or recesses and adapted to sealingly engage the inner surface of the housing. Alternatively, the sealing means may comprise a sealing member associated with the housing. However, in the case of apparatus in accordance with the present invention and having two orthogonally oriented, non overlapping recesses each having opposed side edges, there is preferably provided sealing means associated therewith and adapted to seal the body member for sliding movement against the inner surface, the opposed end edges of the recess being sealed to the body member by a portion of the sealing means adjacent the end edges and associated with the other recess. The sealing means may take any suitable form such as a seal member mounting groove provided in the edges of the recess and adapted to receive seal members. Preferably, the ends of one pair of sealing means associated with one recess substantially intersects the sealing means associated with the other recess, to thereby minimize the number and complexity of the sealing elements. Alternatively, the sealing means may comprise sealing elements adapted to be urged into contact with the bearing inner surface o.f the housing, the urging force being provided by any suitable means such as utilizing a multicomponent body member adapted to be expanded against the inner surface of the housing in response to pressure bled from the high pressure side of the pump.

The porting of the apparatus may take any suitable form, the porting being selected according to the requirements of operation of the apparatus and the configuration of the respective pumping chambers formed by the body member and the piston portions of the piston members. Preferably, the housing is provided with an inlet port and an outlet port, the ports being positioned whereby movement of the body member relative to the housing serves to control the opening and closing of the ports relative to the motion of the pistons in said recesses such that a fluid my be pumped from the inlet port to the outlet port. In air or other gas pumping or engine apparatus, the ports may additionally or alternatively be provided with valves to control gas flow therethrough. For example, the inlet valve may be provided with a reed valve or the like.

The shaft portions adapted to drive or be driven according to whether the apparatus is used as a pump or as an engine. In pumping applications, it is preferred that one shaft portion be adapted to be driven, whereby the apparatus serves as a pump for transferring fluid from the inlet port to the outlet port. Alternatively, the inlet port may be adapted to receive a fluid under pressure for driving the pistons, whereby one shaft may be driven thereby and the apparatus serves as a motor.

In order that this invention may be more easily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate a preferred embodiment of the invention, wherein:-

FIG. 1 is a perspective view of fluid displacement apparatus in accordance with the present invention;

FIG. 2 in a cut away perspective sequence of views illustrating operation of the apparatus of FIG. 1. FIG. 3 is a sectional view through the housing of the apparatus of FIG. 1;

FIG. 4 is an exploded view of a multicomponent body member of the apparatus of FIG. 1, and

FIG. 5 is an end view of a component of the body member of FIG. 4.

In the figures there is illustrated a fluid displacement apparatus configured as a rotary displacement pump and comprising a housing 50 comprised of housing portions 51 defining in assembly a substantially spherical cavity. The cavity is adapted to accommodate a body member 10 having a pair of orthogonal recesses 11, 12 formed therein. A pair of piston members 13, 14 each comprising a "U" shaped piston portion 15 and a shaft portion 16 are adapted to engage for sliding motion within its respective recess 11 or 12. Each piston portion 15 comprises a part spherical plug having a piston face on each side. The housing 50 has an inner spherical surface 17 adapted to bear a part spherical outer surface 20 of the body member 10 about the recesses 11, 12. The outer surfaces 21 of the piston portions 15 are also of part spherical form to sealingly engage the inner spherical surface 17.

The body member recesses 11, 12 and the piston portions 15 in assembly define four isolated compression chambers. The shafts 16 are secured to extend along axes of symmetry of the pistons 15 and are disposed at an angle with respect to each other. Either one of the shafts may be designated a power take-off or delivery shaft and be provided with a shaft extension 22 extending through a bearing 56 provided in a bore through the housing 50. The housing 50 is provided with a pair of ports 70 which are inlet or exhaust depending on the direction of rotation of the shafts 16.

In figure 3 there is illustrated a detail cross section of the housing 50 comprising a pair of housing members 51 having relatively angled end faces 52, 53 and adapted to be joined at partition line 54, partition line 54 being disposed at an angle bisecting the included angle between the angled end faces 52, 53.

Each of the housing members 51 define a substantially hemispherical cavity 55, the inner surface of each hemispherical cavity 55 being relieved to accept annular bearing/seals 56. The bearing/seals are sealably retained in the hemispherical cavities 55 by o-rings 57. Each bearing/seal comprises a pair of part spherical surface bearing portions 60 separated by an annular oil gallery 61 adapted to receive oil from the high-pressure side of the apparatus via an oil duct 62 communicating with an annular passage 63 provided in the rear of the bearing/seals 56, the annular passage 63 communicating with the annular oil gallery 61 via connecting ports 64.

Milled through the housing 50, perpendicular to each of the angled end faces 52 and 53 and concentric with the bearing/seals 56 are bores 65, 66 adapted to receive the shaft portions of the piston members. About the partition line 54 on each side of the housing are provided ports 67 comprising an elongate port 70 leading from the inner surface of the hemispheric cavities 55 and disposed symmetrically about the partition line 54, tapering within the material of the housing members 51 to exit the housing through a threaded connection bore 71. On the output side of the pump, the output port 67 communicates with the oil duct 62 to provide pressurized oil supply to the bearing/seals 56. Illustrated in figures 4 and 5 and adapted for mounting within the housing 50 is a multicomponent body member 72 comprising a central spider portion 73 of cruciform shape and being provided with orthogonal annular recesses 74, 75.

The annular recesses 74, 75 are bounded by part conical side walls 76, 77 joined across their base by a part cylindrical inner wall 80. The part conical side walls 76, 77 have a theoretical apex at the geometric centre of the spider portion 73, which centre also comprises the centre of curvature of the part cylindrical inner wall 80. The material of the central spider portion 73 between the orthogonal annular recesses 74, 75 are provided with part spherical outer surfaces 81 and are bounded by seal grooves 82.

The cruciform faces 83, 84 of the central spider portion 73 are conically milled and the centre of the cruciform faces are joined by a central bore 85 through the central spider portions 73. The cruciform faces are adapted to mate with respective end portions 86, 87, having an inner part conical face 90 having a central spigot 91 adapted to engage the central bore 85. The end portions 86, 87 each have milled in their outer face a part annular recess 92 of the same geometric configuration as the orthogonal annular recesses 74, 75. The outer side edges of the end portions 86, 87 are provided with a part spherical bearing surface 93 of the same spherical configuration as the part spherical outer surfaces 81 of the central spider portion 73.

The end portions 86, 87 are in use mounted to respective cruciform faces 83, 84 of the central spider portion 73 in orthogonal relationship such that each inner part conical face 90 of the end portions 86, 87 closes respective ends of the orthogonal annular recesses 74, 75 to form separate chambers within which piston portions of piston members may separately operate, the end portions being fixed in position relative to the central spider portion 73 by fixing means interconnecting the spigots 91 (not shown).

The outer edges of the part annular recesses, where they meet with the part spherical bearing surface are provided with seal grooves 94 adapted to coincide with the adjacent portions of the seal grooves 82 on the central spider portion 73 to provide a pair of seal grooves per recess, extending about 270 degrees of the circular section described at the seal groove, the 270 degree seal sections each serving to close a side of the annular recesses as well as closing an end of the other annular recess.

Apparatus in accordance with the abovedescribed embodiment functions in the following manner. The piston members 13, 14 are offered up to the recesses 11, 12 of the body member 10 such that the piston portions 15 are assembled to the body member and in assembly the body member and piston members are accommodated in the spherical interior space of the housing casing members 51. The varying-capacity working chambers 23, 24, 25, 26 by the recesses 11, 12 of the body member and the piston portions 15 are adapted to receive liquid or gas supplied to the port 70 in housing 50. A pressure will build up in a working chamber or two .chambers if chambers overlap.

In the FIG. 2 the apparatus is illustrated in a sequence of rotation with chamber 23 pressurised, chambers 23 and 24 in a mid position, chamber 25 fully exhausted mid way between ports and chamber 26 fully expanded mid way between ports. Shading and hatching are used in this figure to enhance distinctions between the respective components. The outer edges 27 of the pistons lay parallel with the circumference of the ports 70. A pressure differential between chambers 23 and 24 give rise to forces acting upon the side face 30 of piston portions 15 and end face 31 of the piston portions 15.

Forces acting on the recesses and the piston end surface 31 will always remains neutral, the force acting on surface 30 being the side of piston 15 will cause movement of the piston around its axes, and, with the coupling of forces through the body member, the turning moment is transferred to the output shaft 16. The body member turns on surface 17 and will move to a neutral position as the reaction between the pistons pivoting relative to the body member will act to turn piston 15 about its axis. With one chamber only the turning force is at maximum. With two chambers the turning moment is transferred from one piston to the other giving a continuous output from any position.

The abovedescribed embodiment of the present invention is described with reference to its application as a pump. However, it is envisaged that the apparatus abovedescribed, with such modifications as may be determined by persons skilled in the relevant art, may be effectively used as a steam engine, compressor, hydraulic motor or vacuum pump. The invention in accordance with the abovedescribed embodiment provides a fluid displacement apparatus in which, owing to an increase in useful volume of working chambers and reduction of length of contact of the moving parts of the apparatus with the inner surface of a spherical housing, an increase in the volumetric efficiency is achieved over the apparatus of the prior art.

It will of course be realised that while the above has been given by way of illustrative example of this invention, all such and other modi ications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of this invention as defined in the claims appended hereto.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:-

1. Fluid displacement apparatus including:- a housing defining a substantially spherical chamber; a pair of piston members having outer faces sealably engaged with the inner surface of said chamber and being mounted for rotation about respective axes each passing through the spherical centre of said housing; a body member having outer extremities sealably engaged with the surface of said chamber and respective elongate recesses to receive said piston members for sliding periodic movement rotationally coupling said piston members, and porting provided through said housing and being in periodic communication with end regions of said recesses.

2. Fluid displacement apparatus according to Claim 1, wherein said recesses comprise a pair of orthogonal recesses each extending circumferentially about said body member, said piston members being disposed in said recesses such that a side wall portion of a piston member located in one said recess forms an end wall for the other recess.

2. Fluid displacement apparatus according to Claim 1, wherein said recesses comprise a pair of part annular recesses bounded by opposed, radially divergent side walls, a pair of end walls and a substantially part cylindrical base wall.

3. Fluid displacement apparatus according to any one of the preceding Claims, wherein said piston members are each provided with a shaft portion for mounting in a bearing provided in said housing for rotation about said respective axes.

4. Fluid displacement apparatus according to Claim 3, wherein one of said shaft portions extends out of said housing.

5. Fluid displacement apparatus according to Claim 4, wherein said one shaft portion is adapted to be driven, whereby the apparatus serves as a pump for transferring fluid from the inlet port to the outlet port.

6. Fluid displacement apparatus according to Claim 4, wherein said inlet port is adapted to receive a fluid under pressure for working said piston members, whereby said one shaft is driven and the apparatus serves as a motor.

7. Fluid displacement apparatus according to Claim 2, wherein said body member is sealed for sliding movement against the inner substantially spherical surface of said housing via a sealing member disposed about the outer periphery of said recesses.

8. Fluid displacement apparatus according to Claim 3, wherein each said recess has opposed side edges provided with sealing means adapted to seal said body member for sliding movement against said inner surface, the opposed end edges of said recess being sealed to said body member by a portion of the sealing means adjacent said end edges and associated with the other said recess.

9. Fluid displacement apparatus according to Claim 1, wherein said porting includes an inlet port and an outlet port, said ports being configured whereby movement of said body member relative to said housing serves to control the opening and closing of said ports relative to the relative motion of the said pistons in said recesses such that a fluid may be transferred from the inlet port to the outlet port.

10. Fluid displacement apparatus substantially as hereinbefore defined with reference to the accompanying drawings.