WO1983003282A1

WO1983003282A1 - Orbital engines

Info

Publication number: WO1983003282A1
Application number: PCT/AU1983/000032
Authority: WO
Inventors: Engine Company Proprietary Limited Orbital
Original assignee: Orbital Engine Co Pty Ltd
Current assignee: Orbital Engine Co Pty Ltd
Priority date: 1982-03-12
Filing date: 1983-03-11
Publication date: 1983-09-29
Anticipated expiration: 1984-09-12
Also published as: EP0103592A1; IT1161109B; FR2523213A1; IT8320032A0

Abstract

Un moteur orbital comprend un piston (13) monté excentriquement sur un arbre (16) tourillonné dans une enceinte (10) de sorte que le piston (13) orbite dans l'enceinte (10) lorsque l'arbre (16) tourne. Un élément de commande (61) appuyé sur l'enceinte (10) décrit un trajet orbital correspondant au trajet souhaité du piston (13) et est contraint à suivre ce trajet par une pluralité de manivelles secondaires (43) ayant la même excentricité que l'arbre (16). L'élément de commande (61) est relié au piston (13) par une languette (69) et une fente (72) ou par une attache de connexion (91) qui ne permet pas de mouvement relatif entre le piston (13) et l'élément de commande (61) dans le sens circonférentiel, mais permet un mouvement relatif dans les sens axial et radial. L'élément de commande (61) s'appuie sur un roulement (62) et se déplace angulairement à celui-ci autour de l'axe excentrique du piston (13). Le roulement (62) se déplace linéairement sur l'arbre (16) radialement à celui-ci et à l'axe excentrique du piston (13).An orbital motor includes a piston (13) eccentrically mounted on a journalled shaft (16) in an enclosure (10) such that the piston (13) orbits in the enclosure (10) as the shaft (16) rotates. A control element (61) supported on the enclosure (10) describes an orbital path corresponding to the desired path of the piston (13) and is constrained to follow this path by a plurality of secondary cranks (43) having the same eccentricity as the tree (16). The control element (61) is connected to the piston (13) by a tab (69) and a slot (72) or by a connecting clip (91) which does not allow relative movement between the piston (13) and the control element (61) in the circumferential direction, but allows relative movement in the axial and radial directions. The control element (61) rests on a bearing (62) and moves angularly to the latter around the eccentric axis of the piston (13). The bearing (62) moves linearly on the shaft (16) radially thereto and to the eccentric axis of the piston (13).

Description

ORBITAL ENGINES

This invention relates to motors, particularly internal combustion engines, of the oscillating rotary type wherein a piston member is mounted within a housing and a 5 plurality of vanes define chambers between the housing and the piston, said chambers varying in volume in sequence in response to oscillating rotary movement between the piston member and housing.

The piston member is normally rotatably mounted 10 eccentrically on a shaft journalled in the housing, so that the movement of the piston member causes the shaft to rotate in the housing. In such motors it is necessary to ensure that the piston member does not rotate relative to the housing, that is, it retains a constant angular relation 15 with respect to the housing. It has previously been proposed to restrain the piston member from rotation by providing a secondary eccentric connection between the piston member and the housing, having the same eccentricity as the piston member has with respect to the shaft. In 20 Australian Patent No. 467415 the secondary eccentric connection is in the form of a plui-ality of cranks, each of the same eccentricity as the crankshaft carrying the piston member, and each having one journal rotatably supported in the housing and the other in the piston member. 25 During the varied conditions of operation, particuarly in an internal combustion engine, the piston member and housing are subjected to a variety of thermal and mechanical conditions, each subject to variation, resulting in thermal and mechanical distortions of such components as the 30 crankshaft, the piston member and the housing. The controlling of the motion of the piston member by a plur¬ ality of eccentric cranks, necessitates sufficient clearance in the bearings thereof to allow for the abovementioned mechanical and thermal distortions. This requires a 35 relatively loose fit of the eccentric journals and their bearings, resulting in a loss in the degree of control preventing rotation of the piston member and a high rate of wear. Alternatively, if the clearance is selected to provide accurate control of the motion of the piston member without rotation, the mechanical and thermal distortions occurring during normal operation will result in excessive friction on the various eccentric cranks and the shaft, with the risk of seizure and premature wear of the bearings.

In Australian Patent No. 491267 there is proposed the use of a stabilizer plate as an intermediate component in the connection between the piston member and the housing.

This construction will permit limited linear movement between the stabilizer plate and the piston member.

The stabilizer plate is rotatably mounted directly on the crankshaft, coaxial with the piston member. Accordingly distortion of the crankshaft places high loads on the bearing between the stabilizer plate and the crankshaft, and the bearings of the eccentrics connecting the stabilizer plate to the housing. These bearing loads result in high wear rates, particularly in view of the restrictions on bearing size as a result of space restraints. It is therefore the object of the present invention to provide a construction wherein the stabilizer plate will effectively control the movement of the piston member and accommodate the thermal and mechanical distortions in the engine under operating conditions. With the above stated object in view there is provided a motor comprising: a housing member having a cavity defined by an internal peripheral wall and opposed end walls, a shaft supported for rotation relative to said housing member and having a shaft axis of rotation, a piston member mounted on said shaft eccentrically with respect to said shaft axis of rotation to orbit within said housing cavity upon rotation of said shaft, said piston member having a piston axis, parallel to the shaft axis, plurality of vanes within said housing cavity and spaced circumferentially from one another about the piston member to divide said cavity into a plurality of chambers , vanes support means carried by at least one of said piston member and housing member and supporting said vanes in engagement with said housing walls and with said piston member as said piston member orbits, chambers vary in volume in sequence as said piston member orbits, a bearing member supported on the shaft to rotate therewith relative to the housing member and to provide for linear movement of the bearing member relative to the shaft to accommodate deflection of the shaft in a direction at right angles to the shaft axis, a control member supported on the bearing member for angular movement relative thereto about the piston axis, piston member connecting means operatively connecting said piston member and said control member to restrict angular movement of said control member with respect to said piston member about the piston axis, and housing connecting means operatively connecting said control member to said housing member so that said control member moves in an orbital path relative to the housing corresponding to the orbital path of said piston member.

Conveniently the piston member connecting means also permits linear movement between the piston member and the control member in a plane at right angles to the piston member axis. Preferably the linear movement between the bearing member and the shaft is in direction radial to the piston axis, and preferably also radial to the shaft axis, that is, in the direction of the eccentricity of the piston axis to the shaft axis. This is the direction of the main distortion of the crankshaft. In one embodiment the bearing member and shaft have co-operating slide surfaces that permit the linear movement therebetween. In an alternative construction the bearing member and shaft are connected by links that are arranged to accommodate the linear movement between the shaft and bearing member, and also cause the bearing member to rotate with the shaft. Preferably the links are non-pivotally connected to the shaft and bearing member, and flex to accommodate the linear movement. Preferably the connection between the control member and the piston member comprises a tongue formed on one of said members and a slot formed on the other of said member. The tongue is slidable in the slot in the direction radial to the piston axis to accommodate relative movement between the piston member and control member in the radial direction. The slot may be formed in an insert that is mounted in the piston member, for ease of manufacture. Preferably the insert has a limited angular movement relative to the piston member to accommodate misalignment between the slot and tongue arising from manufacturing tolerances, and distortion under operating conditions.

Alternatively the means connecting the control member to the piston member may also comprise links that are arranged to accommodate the limited linear movement and mis¬ alignment. The links may be non-pivotally connected to the piston member and shaft and flex to accommodate the necessary movements therebetween.

Conveniently the means connecting the control member to the housing comprise a secondary crank member or members each having two journal sections parallel to the axis of the shaft, one rotatably supported in the housing and the other in the control member. The eccentricity of said journal sections of each secondary crank member is equal to the eccentricity of the piston member relative to the shaft. The provision of the bearing member having limited linear movement relative to the crankshaft accommodates distortion of the crankshaft so as to not give rise to undue higher loads on the bearing between the shaft and bearing member.

The invention will be more readily understood from the following description of practical arrangements of the engine incorporating a control member interconnected between the housing and piston members, as illustrated in the accompanying drawings.

OMPI In the drawings -

Figure 1 is an axial section through a vane-type engine.

Figure 2 is a diametral section through the piston member and crankshaft showing one embodiment of the control member and its mounting on the crankshaft and piston member.

Figure 3 is a further diametral section showing an alternative construction of the control member and its connection to the piston member and crankshaft. Referring now to the drawings, the engine comprises a housing 10 having opposed end plates 11, 11A. Bearings 15 mounted in the end plates rotatably support the crankshaft 16 for rotation about the axis of the housing 10. A piston member 13 is mounted on the eccentric journal 17 of the crankshaft 16. The space between the piston member 13 and the housing 10 is divided into a number of combustion chambers by the provision of vanes 18, which at the inner end abut respective flat faces 19 on the piston and are slidably supported into slots 18A in the housing 10 (Figure 3).

Referring now to Figure 2 of the drawings. In this construction the control member or stabilizer plate 61 is mounted on a bearing member 62, so that the stabilizer plate 61 may angularly move relative to the bearing member 62 on the bearing surface 64, about the axis 63 of the eccentric journal 17 of the crankshaft, which is the same axis as that of the piston member 13.

The bearing member 62 is provided with two internal parallel slide surfaces 65 which are in sliding engagement with complimentary parallel slide surfaces 66 formed on the crankshaft. The slide surfaces on the bearing member 62 and the crankshaft are parallel to the common axial plane 70 containing the axis 70a of the crankshaft and the axis 63 of the piston member 13 and crankshaft eccentric journal 17. By mounting the bearing member on the crankshaft in this manner, the bearing member may move in the direction of the common axial plane 70 relative to the crankshaft, to accommo¬ date any distortion or deflection to the crankshaft which

OMPI may arise during operation of the engine.

The stabilizer plate 61 is rotatably mounted on the periphery of the bearing member 62, and is connected to the end plate of the engine by the series of four eccentric crank members 43, each eccentric has one journal 43a rotatably supported in the stabilizer plate at the respective locations 68 and the outer journal 43b of each eccentric rotatably supported in the housing end plate 11a. The construction and arrangement of the eccentrics is substantially the same as that disclosed in Australian

Patent No. 491267, and further details of the construction may be obtained therefrom.

The stabilizer plate has provided on the external surface a tongue 69 having substantially flat opposite faces 71 which are parallel to an axial plane 70 passing through the centre line of the eccentric journal 17 of the crankshaft. The tongue 69 is received in a complementary recess 72 in an insert 73 mounted in the piston member. The walls of the recess are parallel, and slidably engage the tongue. The insert 73 is received in an axially extending aperture 74 in the piston member, and has freedom to angularly move therein about its- axis, which is parallel to axis 63 of the piston member 13.

An alternative embodiment of the present invention is disclosed in Figure 3 of the drawings wherein the general construction of the piston member and stabilizer plate are as previously described, and the stabilizer plate is connected to the housing end plate of the engine by a series of four eccentric crank members in the same manner as previously described with reference to Figs. 1 and 2. In this construction a bearing member 80 is provided to rotatably support the stabilizer plate 61a, however, the manner of supporting the bearing member on the crankshaft is modified. As shown in Figure 3, the flexible metal member 81 is rigidly attached at approximately its midpoint to the crankshaft by the bolt 83, and the respective ends the flexible member are attached by bolts 84 to the bosses 85 on

C FI V.IΓO the bearing member. The further flexible member 86 is attached by the bolt 87 to the crankshaft, and to the bearing member by the bolt 89.

The two flexible members 81 and 86 are disposed in a general parallel relationship, and thus flexing of these members in a direction normal to their length, permits the bearing member to move in a plane at right angle to the crankshaft axis relative to the crankshaft, to accommodate minor movements therebetween as a result of deflection or distortion of the components in use. However, as the flexible members 81 and 86 are relatively rigid in the direction of their length and width, the bearing member is caused to rotate with the crankshaft, and as previously described the stabilizer plate 61a is free to rotate or angularly move on the bearing member.

The stabilizer plate 61a is connected to the piston member 13a by a further flexible member 91 similar to the flexible members 81 and 86. The centrally located bolt 92 attaches the flexible member 91 to the stabilizer plate 61a and the bolts 93, adjacent the ends of the flexible strip, attach the latter to the piston member. Flexing of the member 91 will accommodate movement between the stabilizer plate and the piston member in the plane at right angles to the piston axis, including movement essential in the direction of the eccentricity of the crank, while restraining the piston member and stabilizer plate from relative angular movement.

This construction has the advantage, over that described with reference to Figure 2, of the elimination of the bearing surfaces between the bearing member and the crankshaft, and between the tongue of the stabilizer plate and the recess in the piston member. These bearing surfaces require considerable accuracy in machining, which is avoided by the construction, wherein relative movement is accommo- dated by flexing of the relatively thin members 81, 86 and 91. Also this construction eliminates the need for lubri¬ cation of the bearing surfaces previously provided. The flexible members 81, 86 and 91 are conveniently made of material sufficiently resilient to accommodate the required degree of flexing within its elastic range and is fatigue resistant to have an acceptable working life. Conveniently the flexible members are made of a suitable grade of spring steel. The flexible members are also conveniently in the form of a strip with a substantial width relative to the thickenss thereof. The strip is arranged in use so that said thickness extends in the direction of required flexibility to accommodate the relative movement between the components interconnected by the flexible member.

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Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A motor comprising: a housing member having a cavity defined by an internal peripheral wall and opposed end walls, a shaft supported for rotation relative to said housing member and having a shaft axis of rotation, a piston member mounted on said shaft eccentrically with respect to said shaft axis of rotation to orbit within said housing cavity upon rotation of said shaft, said piston member having a piston axis parallel to the shaft axis, a plurality of vanes within said housing cavity and spaced circumferentially from one another about the piston member to divide said cavity into a plurality of chambers , vanes support means carried by at least one of said piston member and housing member and supporting said vanes in engagement with said housing walls and with said piston member as said piston member orbits, whereby said chambers vary in volume in sequence as said piston member orbits, a bearing member supported on the shaft to rotate therewith relative to the housing member and to provide for linear movement of the bearing member relative to the shaft to accommodate deflection of the shaft in a direction at right angles to the shaft axis, a control member supported on the bearing member for angular movement relative thereto about the piston axis, piston member connecting means operatively connecting by said piston member and said control member to restrict angular movement of said control member with respect to said piston member about the piston axis, and housing connecting means operatively connecting said control member to said housing member so that said control member moves in an orbital path relative to the housing corresponding to the orbital path of said piston member.

2. A motor as claimed in claim 1 wherein the piston mem¬ ber connecting means is adapted to permit linear movement between the piston member and the control member in a plane at right angles to the piston axis.

3. A motor as claimed in claim 1 or 2 wherein the piston member connecting means is adapted to permit limited linear movement between the piston member and the control member in the direction parallel to the piston axis.

4. A motor as claimed in claim 1, 2 or 3 wherein the bearing member and shaft are adapted so said linear movement therebetween is in a direction radial to both the shaft axis and the piston axis.

5. A motor as claimed in any one of claims 1 to 4 where¬ in the bearing member and shaft have co-operating bearing surfaces in sliding engagement and adapted to control the direction of said linear movement and prevent relative angu¬ lar movement therebetween.

6. A motor as claimed in any one of claims 1 to 4 includ¬ ing a linkage system inter—connecting the bearing member and shaft and adapted to control the direction of said linear movement, and resist relative angular movement therebetween.

7. A motor as claimed in any one of claims 1 to 4 including an arrangement of links each non-pivotally connected to the bearing member and the shaft, each link being flexible in the direction of said linear movement, said links being relatively arranged to permit said limited linear movement by flexing of at least some of the links and to prevent relative angular movement between the bearing member and shaft.

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8. A motor as claimed in claim 7 having two said flexible links arranged substantially parallel and extending substantially at right angles to the direction of said linear movement and to the direction of the shaft axis, said links being spaced in the direction of said linear movement, and each link being rigidly attached to the bearing member and shaft at respective locations spaced in a direction transverse to the direction of linear movement.

9. A motor as claimed in claim 7 or 8 wherein the links are spring steel strips arranged to be flexible in the direction of said linear movement.

10. A motor as claimed in any one of the preceding claims wherein the piston member connecting means comprises a tongue on one of the piston member or control member and a slot in the other, said tongue being slidable in the slot in a direction radial to the piston axis.

11. A motor as claimed in claim 10 wherein the tongue is also slidable in the slot in a direction parallel to the piston axis.

12. A motor as claimed in claim 10 or 11 wherein the slot is formed in an insert, and said insert is attached to said other member for limited angular movement relative thereto about an axis parallel to the piston axis.

13. A motor as claimed in any one of claims 10 to 12 wherein the tongue is on the control member and the slot is in the piston member. - - 'i. -

-12-

14. A motor as claimed in any one of claims 1 to 9 wherein the piston member connecting means comprises a linkage system inter—connecting the piston member and the control member and adapted to permit movement therebetween in a direction radial to the piston axis.

15. A motor as claimed in any one of claims 1 to 9 wherein the piston member connecting means comprises an arrangement of links each non-pivotally connected to the piston member and control member, each link being flexible in one direction, and the links being arranged to permit relative movement between the piston and control members in a direction radial to the piston axis by flexing of the links.

16. A motor as claimed in claim 15 wherein said arrangement of links has two links substantially parallel and extending substantially at right angles to said radial direction and to the direction of the piston axis, each link being rigidly attached to the piston and control members at respective locations spaced in the direction of the length of the link.

17. A motor as claimed in any one of claims 1 to 9 where¬ in the piston member connecting means comprises an elongate member extending substantially at right angles to said rad¬ ial direction and the direction of the piston axis, said elongate member being flexible in a direction both at right angles to the length thereof and to the direction of the piston axis, and means rigidly connecting the elongate member at spaced locations in the direction of its length to one of the piston and control members and to the other of said members intermediate said spaced locations.

18. A motor as claimed in claim 17 wherein the elongate member is connected to the piston member at said spaced loc¬ ations.

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19. A motor as claimed in any one of claims 15 to 18 wherein each of the links or elongate member is a spring steel strip.

20. A motor as claimed in any one of the preceding claims wherein the housing connecting means comprises at least one secondary crank member having two journal sections each parallel to the shaft axis, one rotatably supported in the housing and the other in the control member, the eccentricity of the journal sections being equal to the eccentricity of the piston member relative to the shaft.

21. A motor substantially as hereinbefore described with reference to and as illustrated by the Figs. 1 and 2 or Fig. 3 of the accompanying drawings.

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