WO1983002978A1

WO1983002978A1 - Improved gas seal for vane type internal combustion engine

Info

Publication number: WO1983002978A1
Application number: PCT/AU1983/000024
Authority: WO
Inventors: Engine Company Proprietary Limited Orbital
Original assignee: Ewing, Peter, Anthony; Czwienczek, Peter, William
Priority date: 1982-02-22
Filing date: 1983-02-22
Publication date: 1983-09-01
Also published as: EP0105282A1; IT1161074B; IT8319674A0; FR2522068A1

Abstract

An orbital engine has vanes (70) supported by the engine housing and piston member (40) to reciprocate radially in the housing as the piston member (40) orbits. Vane legs (72) extending along the end faces (42) of the piston member (40) slide relative thereto in a direction at right angles to the reciprocating movement of the vane (70). A seal assembly mounted in each vane leg (72) has a seal pad (86) directed towards and co-operating with a seal ring (60) carried in a groove in the end face (42) of the piston member (40) and a base portion (85) which engages a face in the end wall of the housing so that the vane (70) may move in the axial direction of the piston member axis relative to the seal assembly and independently thereof. Springs are provided to urge the seal pad (86) radially outward to engage the transverse face (80a) of the vane (70) which slides on the outer periphery of the piston member (40) to maintain sealing between the external corner of the piston member (40) and the internal corner of the vane (70) at the junction of the vane transverse face (80a) and the vane leg (72).

Description

"IMPROVED GAS SEAL FOR VANE TYPE INTERNAL COMBUSTION ENGINE "

This invention relates to a seal for incorporation in a vane type internal combustion engine.

More specifically the invention relates to a seal for use in an internal combustion engine of the type having a housing, a shaft mounted for rotation relative to the housing, a piston member carried by said shaft, said piston member having a peripheral surface and opposite end faces, the housing having respective end faces in spaced opposed relationship to the respective piston member end faces, a plurality of vanes (arranged to form with the housing and the piston member a plurality of chambers which vary in capacity in response to relative rotation between the shaft and the housing, each vane having a transverse face in sliding engagement with the peripheral surface of the piston member and a leg portion extending inwardly from the transverse surface along one of the end faces of the piston toward the shaft. One example of this type of engine is disclosed in

Australian Patent No. 467415.

In this type of engine there is a particular problem in maintaining an effective seal between the vanes and the piston member, particularly in the area of the junction between the transverse face of the vane and the leg portion. This problem is aggravated by the fact that the vane is more difficult to cool than the piston member and housing, and accordingly the expansion of the vane in the transverse direction is somewhat greater than that of the piston member, resulting in the vane leg tending to move away from sealing contact with the end face of the piston member. A seal construction for this area of the vane type engine is disclosed in Australian Patent No. 477125 which will accommodate the movement of the vane leg relative to the end face of the piston member in the transverse direction of the vane.

However, this construction does not accommodate relative movement between the vane leg and the piston member in other directions. In particular there is movement between the vane leg and piston member in the longitudinal direction of the leg due to thermal expansion and working clearance. It is important to maintain an effective seal where the external corner of the piston member, formed at the junction of the end face and peripheral surface thereof, mates with the internal corner of the vane, formed at the junction of the vane transverse face and the vane leg.

In the seal construction proposed in said prior Australian Patent expansion of the vane leg would displace the seal arrangement, provided in the above referred to corner area, in a radially inward direction and reduce the effectiveness of the seal. This problem arises because the seal arrangement has no freedomm of movement relative to the vane leg in said radial direction.

Also the seal arrangement as proposed in said prior patent should maintain an effective seal with the opposite walls of the groove in which the vane leg reciprocates.

However, the prior proposal only allows for limited wear or expansion in the direction transverse to the groove, and in such conditions it is difficult to maintain an effective sealing relation with the opposite walls of the groove over an extended life.

It is therefore the object of the present invention to provide a seal construction for incorporating in a vane type engine to maintain an effective gas seal in the area of the junction between the vane body and the vane leg where it co-operates with the end face and peripheral surface of the piston member.

With this object in view there is provided according to the present invention an engine of the aforementioned type wherein each vane leg portion is supported in a groove in a housing end wall for reciprocation relative to the end wall as the shaft rotates, each vane having a carrier supported by a leg portion thereof to move therewith as the vane reciprocates in the housing, said carrier having a base portion and a seal portion, the base portion engaging a face in the housing end wall for sliding movement therealong in the direction of reciprocating movement of the vane relative to the housing, the seal portion being located adjacent the junction of the vane leg portion with the transverse face of the vane, said seal portion having a sealing face engaging a seal means in the piston member end face, said sealing face extending to the transverse face of the vane, resilient means urging the seal portion into engagement with the transverse face of the vane and preferably also with the opposite walls of the groove in the end wall of the housing, the vane leg portion being movable in the axial direction of the shaft relative to the piston and housing independently of the carrier. The seal portion may be integral with the remainder of the carrier or may be a separate component co-operating with the carrier so as to be held in engagement with a seal member or members carried by the end face of the piston member. In a construction wherein the seal portion is separate from the carrier, resilient means are interposed between the carrier and the seal portion to urge the base portion of the carrier into engagement with a face in the end wall of the housing, and the seal portion into engagement with the seal means carried by the end face of the piston member. In a further modification the seal portion may be made of two elements located side by side transverse to the recess in the vane leg portion. Resilient means may be provided. to urge the respective elements into sealing engagement with the opposite walls of the groove in the end wall of the housing, in which the vane leg portion reciprocates. In a preferred construction the seal portion is separate to the carrier member, and is divided into two elements along a line inclined to the direction of reciprocation of the vane in the housing. Resilient means are provided to apply a force to the two elements, in a direction inclined to the line of division between the elements, whereby the same resilient means will urge the elements in a direction parallel to the direction of reciprocation of the vane leg portion in the housing, and in a direction at right angles thereto. In a further embodiment the carrier is of a two part construction comprising two generally identical parts which are arranged in a side by side relationship in the vane leg, each part having a base portion that is in sliding contact with a face in the end wall of the housing to slide there along the direction of reciprocation of the vane. Each carrier part has an integral seal portion at the opposite end to engage with the seal means in the end face of the piston member. Respective resilient means are provided to urge the seal portion of each carrier part into engagement with the transverse face of the vane, whilst further resilient means are provided to urge the seal portions into engagement with the respective side walls of the groove in the end face of the housing. A wedge shaped element is located between the two seal portions, extending in the direction of the reciprocation of the vane in the housing. The further resilient means previously referred to act on the wedge element to urge it in a direction towards the piston end face, so that it will form a seal against the inner edges of the respective seal portions, and they are urged apart to engage the respective opposite walls of the groove in the housing.

The present invention will be more readily understood from the following description of various practical arrangements of the invention as illustrated in the accompanying drawings. In the drawings:

Figure 1 is a perspective view, partly in section, of a vane type engine, in which the invention is incorporated.

Figure 2 is an enlarged perspective view of a portion of the piston member and one vane from the engine shown in Figure 1.

Figure 2a is an enlarged exploded view of vane leg seal assembly shown in Figure 2 and the adjacent portions of the vane and vane leg.

Figure 2b is a fragmentary view of portion of the vane leg seal assembly of Figure 2a in the asssembled condition. Figure 3a is a sectional plan view of a modified one part carrier member to support the two part seal portion as shown in Figure 2a.

Figure 3b is a side elevation of the seal assembly as shown in Figure 3a.

Figure 4 is an exploded perspective view of a modification of the seal assembly incorporating a one part carrier member and a two element seal portion. The engine disclosed in Australian Patent No. 467415 is illustrated generally in Figure 1 of the drawings wherein the engine generally comprises a housing 9 and opposed end plates 11 (one only shown). The crankshaft 16 is supported in bearings 15 (one only shown) mounted in the respecive end plates, and the piston 40 is mounted eccentrically on the crankshaft 16.

The vanes 70 are supported in the housing end plates for reciprocation in a radial direction with respect to the crankshaft axis. Each vane 70 includes, at each axial end thereof, a leg 72 attached thereto by bolt 83, the legs 72 being slidably supported in radial slots 71 formed in respective end plates 11. The vanes are also slidably supported in transverse slots 20 in the annular portion 10 of the housing. In each end face 42 of the piston member there are provided equally spaced slots 45, one for each vane, arranged in the symmetrical formation about the axis of the piston member. The laterally projecting lugs 76 attached to the inner end of each vane leg 72, extends into the respective slot 45 so that, as the piston member oscillates in a rotary manner in the housing, the vanes reciprocate radially in the housing and slide relative to the piston member, on the flat peripheral surfaces 46 thereof, in a direction normal to the plane of the vane. The seal elements 73, are located in the slots 41 in the radially inner transverse face 80 of each vane, to engage the peripheral surface 46 of the piston member 40. Seal strips 74, on each side of each vane, engage the opposite side walls of the slot 71 in the end plate, which supports the vane. Seal rings 60 are located in grooves in the end faces 42 of the piston member and engage the inner face of each end plate 11. Each vane leg has a control pad seal 86 to co-operate with the sealing ring 60 carried by the piston member.

A portion of the piston member of the above described engine, with one vane assembled thereto, is shown in perspective in Figure 2, with the control pad seal and the support portion of the leg of the vane shown in an exploded enlarged view designated Figure 2(a). As shown in Figure 2 the seal elements 73 extend the full width in the axial direction of the peripheral surface 46 of the piston member to provide a seal to prevent the passage of gas between the transverse face 80 of the vane and the peripheral surfaces of the piston member.

Each vane leg has in the face 90, directed towards the end face 42 of the piston member, a transverse recess 92 which extends the width of the vane leg, and extends downwardly from the junction of the vane leg with the off-set portion 80a of the face 80. The off-set portion 80a is parallel to the transverse face 80 of the vane but positioned slightly below the peripheral surface 4-6 of the piston. It should be noted that the difference in level between the surfaces 80 and 80a is only of the order of 0.08 to 0.15 mm. There is a further transverse recess 93 in the opposite face 91 of the vane leg, and two slots 84- extending through the vane leg between the two recesses 92 and 93.

The two carrier members 81 are each of a generally H-shaped cross section, having a base portion 85, a seal portion 86 and an inter-connecting web 81a. When assembled to the vane leg the webs 81a of the two carrier members are received one in each of the respective slots 84-, and the base portion 85 of each carrier member is located in the recess 93 .whilst the seal portion 86 of each carrier member is located in the forward recess 92. The webs 81a of the respective carrier members 81 are a free fit in the respective slots 84 in the vane leg so that there is limited freedom of movement of the web in all directions relative to the vane leg. The base portions 85 engage the base of the end plate slot 71 that receives the vane leg. The seal portions 86 engage the sealing ring 60 in the end face of the piston. The overall length of the carrier member across the outwardly direction faces of the base portion and seal portion is such that, upon assembly in the slot 71, the face of the seal portions is above the face 90 of the vane leg but not above the inner face 11a of each end plate.

Accordingly the vane leg may move relative to the piston member, as a result of expansion of the vane in the direction transverse to the piston member, independently of the carrier members, and thus without adversely affecting the seal provided by the seal portions with the piston members seal ring 60 and vane surface 80a.

The vane leg 72 is detachably secured to the vane 70, by the bolt 83, so that the carrier members may be conveniently fitted into the slots 84 in the vane leg, and then held in position when the vane leg 72 is attached to the vane. The springs 98 are seated in. the cavities 94 in the vane leg 72 and apply an upward pressure to the respective seal portions of the carrier members so that the upper face 95 of the seal portions are urged into contact with the off-set portion 80a of the vane transverse face 80 which prevents any interference between the seal portions 86 and the sealing elements 73.

The two internal edges 96 of the seal portions of the carrier members are inclined, so that they form between them a slot extending in the direction of the vane leg, and diverge outwardly from the face of the seal portions that engage the seal ring 60 in the end faces of the piston member. Located in this wedge shaped groove is a seal strip 95 of generally diamond shaped cross section. The two forward faces 99 of the wedge seal strip are inclined at an angle complimentary to the inclined end faces of the seal portions, whilst the other two faces 101 may be similarly inclined, but the angle thereof is not necessarily the same as that on the forward faces.

Provided in the inclined edge 96 of each seal portion 86 are two apertures, each receiving a small compression spring and a guide plug 105. The end face of each guide plug is inclined to complement the angle on the rear faces 101 of the wedge seal strip 95. When the springs and plugs 105, and wedge seal strip are all assembled with the carrier members the springs urge the seal strip into the V-shaped groove formed between the edge faces 99 of the seal portions to maintain a seal therebetween. Also the springs force the wedge seal portions of the carrier members apart into sealing engagement with the opposite respective walls of the slot 71 in the end plate.

In an alternative construction the two carrier member described above may be made as an integral one piece unit. This would avoid the use of the wedge seal strip 95 and the springs and plugs 105. However, the springs 98 contacting the lower edge of the seal portion to hold the seal portion in engagement with the transverse face 80a of the vanes will still be required.

In a further modification, also using a one piece carrier, the webs 81a of the carrier may be shortened and spaced more widely apart, so as to pass along either side of a modified vane leg, and having two base portion 85a which are seated in respective grooves 71a, extending on either side of the slot 71 carrying the vane leg. This modification is illustrated in Figure 3a and 3b. The construction shown uses a two element separate seal portion of the same basic construction as previously described with reference to Figure 2(a). Each of the seal portion elements 86a are supported on the flange 81b of the carrier member so they are independently movable relative thereto in the lateral and longitudinal direction of the vane leg. This two element seal portion may also be used on the one piece carrier member construction where the webs of the carrier member pass through slots in the vane leg.

In a further modification, as shown in Figure 4, the seal portion is a separate component from the carrier and is divided along a diagonal line 110 across the face exposed to the piston end face, into two elements 115 and 116. The force applied to the lower element 115 of the split seal portion, by the springs 98 forces the upper section 116 into engagement with the transverse face 80a of the vane. This spring force also cause lateral movement of the elements 115 and 116 relative to one another so that their respective ends are forced into sealing engagement with the opposite walls of the slot 71 in the end plate. An arrangement of springs 112 are located between the elements 115 and 116 of the seal portion and the carrier to maintain the elements in the engagement with the sealing ring 60 in the end face of the piston member. in the embodiment illustrated in Figure 4, the carrier member 81 is of the same general construction as described with reference to Figure 3 however a one piece carrier member having webs that pass through slots in the vane leg may be used. In such a construction the base portion will be located in a recess in the rear face of the vane leg, such as the recess 93 described with reference to Figure 2a.

In yet a further modification the webs 81a do not extend through internal slots in the vane leg but are located in respective recesses in the side faces of the leg.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. An engine of the aforementioned type wherein each vane leg portion is supported in a groove in a housing end wall for reciprocation relative to the end wall as the shaft rotates, each vane leg portion having a carrier supported thereby to move therewith as the vane reciprocates in the housing, said carrier having a base portion and a seal portion, the base portion engaging a face in the housing end wall for sliding movement therealong in the direction of the reciprocating a movement of the vane relative to the housing, the seal portion being located adjacent the junction of the vane leg portion with the transverse face of the vane, said seal portion having a sealing face engaging a seal means in the piston member end face, said sealing face extending to the transverse face of the vane, resilient means urging the seal portion into engagement with the transverse face of the vane, the vane leg portion being movable in the axial direction of the shaft relative to the piston and housing independently of the carrier.

2. An engine as claimed in claim 1 wherein resilient means urge the seal portion into engagement with at least one of the opposite walls of the groove in the end wall of the housing.

3. An engine as claimed in claim 1 wherein the seal portion is in two sections and resilient means are provided to urge the sections into engagement with respective opposite walls of the groove in the end wall of the housing.

4. An engine as claimed in claim 3 wherein a seal element is located between said two sections to form a seal between the sections when the sections are urged into engagement with the respective opposite walls of the groove.

5. An engine as claimed in claim 3 wherein a wedge member is located between and in engagement with said sections and the resilient means urges said wedge member in a direction to establish said engagement between the sections and the opposite walls of the groove.

6. An engine as claimed in claim 1 or 2 wherein the seal portion is divided into said two sections along a line inclined to the direction of reciprocation of the vane leg portion and inclined to the opposite walls of the groove, the respective faces of the two sections defining said division being in sliding engagement, the resilient means urging the seal portion into engagement with the transverse face of the vane being arranged to have a line of action that intersects said division line so as to also urge the respective sections into engagement with the opposite walls of the groove.

7. An engine as claimed in any one of the preceding claims wherein the sealing portion is a separate member mounted on the base portion to reciprocate with the base portion and vane leg portion.

8. An engine as claimed in claim 7 including resilient means interposed between the base portion and separate member to urge the latter into engagement with the sealing means in the piston end face.

9. An engine as claimed in any one of the preceding claims wherein a portion of the base portion extends through the vane leg portion.

10. An engine as claimed in any one of claims 1 to 9 wherein the base portion extends about portion of the vane leg portion.

11. An engine as claimed in any one of claims 1 to 8 wherein the carrier comprises a base plate to slidably engage the base of the groove in the housing end wall in which the vane reciprocates, a web integral with the base plate extending through a slot in the vane leg portion and supporting the seal portion in a recess in the vane leg portion, said web having limited freedom of movement in said slot in the direction of reciprocation of the vane, in the direction at right angles to and end face of the piston member, and in a direction at right angles to both said directions.

12. An engine as claimed in claim 11 wherein the resilient means includes a spring or springs seated in the vane leg portion and engaging the seal portion to urge the latter into engagement with the transverse face of the vane.

13. An engine as claimed in claim 11 or 12 wherein there are two said carriers in each vane leg portion disposed side by side transverse to the direction of reciprocation of the vane.

14. An engine as claimed in claim 13 when appended directly or indirectly with claim 3 wherein the seal portions of the respective carriers constitute said two seal sections.

15. An engine as claimed in claim 13 when appended directly or indirectly to claim 5 wherein the seal portion of each carrier has an outer edge face, each outer edge face engaging a respective opposite wall of the groove in the housing, and each said seal portion has an inner edge face, said inner edge faces defining a slot with the inner edge faces converging towards the end face of the piston member, said resilient means urging the wedge member into said slot and the outer edge faces into engagement with the walls of the groove in the housing.

16. An engine as claimed in claim 15 wherein said resilient means include a spring or springs supported in one or each seal portion, and co-operate with said wedge member to urge the latter into the slot.

17. An engine as claimed in claim 11 wherein there are two webs integral with the base plate extending through a respective slot in the vane leg portion, each said web having said freedom of movement in the respective slot.

18. An engine as claimed in claim 17 wherein a support member integral with said webs is located in said recess in the vane leg and the seal portion is a separate member mounted on said support member.

19. An engine as claimed in claim 10 wherein the base portion comprises two base plates each integral, with a respective web, the webs extend on respective sides of the vane leg portion.

20. An engine as claimed in claim 19 wherein a support member integral with the webs is provided and said seal portion is a separate member mounted on said support member.

21. An engine as claimed in claim 18 including further resilient means urging said separate member into engagement with the seal means in the end face of the piston member.

22. An engine as claimed in any one of the preceding claims wherein said seal portion is located in a recess in the vane leg portion.

23. An engine of the aforementioned type substantially as hereinbefore described with reference to Figures 1, 2, 2a and 2b; Figures 3a and 3b; or Figure 4.