BAFFLE ELEMENT, DIFFUSER PLATE, AND SEAL SYSTEM INCORPORATING A BAFFLE ELEMENT AND A DIFFUSER PLATE

Abstract

A seal system for a bearing chamber of a turbomachine includes a baffle element encircling the axis of the machine. The baffle element is formed with front surface including a plurality of gutter surfaces which are angularly spaced about the rotational axis. The seal system can thus be mounted in any one of a plurality of orientations with respect to the direction of gravity, such that in any of the orientations one of the gutter surfaces is directed downwardly.

Claims

1. A baffle element for a seal system of a turbomachine, the baffle element having a front surface which in use faces axially into a bearing chamber of the turbomachine, and a rear face which in use faces axially away from the bearing chamber, the baffle element comprising: an inner portion defining a circular central opening which in use is positioned on a rotational axis of the turbomachine with a center of the central opening on the axis and the perimeter of the central opening lying in a plane transverse to the axis; a wall upstanding from the front surface of the baffle element at a periphery of the inner portion of the baffle element; and at least two gutter surfaces extending radially-outwardly from the inner portion though respective gaps in the wall at different respective circumferential positions about the center of the central opening.

2. The baffle element of claim 1, wherein at least one of the gutter surfaces is inclined to the plane of the circular central opening.

3. The baffle element of claim 1, wherein the front surface comprises a recess portion which is axially rearward with respect to the central opening of the inner portion of the baffle element, the recess portion defining a circumferentially extending oil reception channel.

4. The baffle element of claim 3, wherein the channel intercepts at least one of the gutter surfaces, whereby oil moving circumferentially in the channel encounters the gutter surface and is directed through the corresponding gap in the wall.

5. The baffle element of claim 3, wherein the channel includes varying cross-sectional area at different circumferential positions, the cross-sectional area at the different circumferential positions being measured as the intersection of the channel with respective planes including the axis, the cross-sectional area being greatest at a circumferential position about the axis which is circumferentially spaced from the at least two gutter surfaces.

6. The baffle element of claim 3, wherein the channel includes a different depth at different circumferential positions, the depth of the channel of at least one circumferential position which is in register with one of the gutter surfaces being less than the maximum depth of the channel.

7. The battle element of claim 1, wherein at least one of the gutter surfaces is substantially flat.

8. A diffuser plate operative for use with a baffle element in a seal system of a turbomachine, the baffle element having a front surface which in use faces axially into a bearing chamber of the turbomachine, and a rear face which in use faces axially away from the bearing chamber, the baffle element comprising: an inner portion defining a circular central opening which in use is positioned on a rotational axis of the turbomachine with a centre of the central opening on the axis and the perimeter of the central opening lying in a plane transverse to the axis; a wall upstanding from the front surface of the baffle element at a periphery of the inner portion of the baffle element; and at least two gutter surfaces extending radially-outwardly from the inner portion though respective gaps in the wall at different respective circumferential positions about the center of the central opening; and the diffuser plate having a front surface defining a central aperture and arranged to conform with the baffle element, wherein upon placing the baffle element against the diffuser plate the diffuser plate supports the baffle element with the central opening of the baffle element in register with the central aperture of the diffuser plate and in a fixed angular position about the central aperture of the diffuser plate.

9. The diffuser plate of claim 8, further comprising a plurality of circumferentially spaced protrusions subtending the central aperture of the diffuser plate and arranged to contact the wall of the baffle element, wherein upon placing the baffle element against the diffuser plate the gutter surfaces extend through respective circumferential gaps between the protrusions.

10. (canceled)

11. (canceled)

12. A turbomachine, comprising: a housing defining a bearing chamber; a shaft having a longitudinal axis, a portion of the shaft being within the bearing chamber; a plurality of bearing elements mounted on the housing within the bearing chamber, the bearing elements supporting the shaft, and permitting the shaft to rotate about the axis; an oil delivery mechanism for supplying oil to the bearing elements; a baffle element having a front surface which faces axially into the bearing chamber, and a rear face which faces axially away from the bearing chamber; a diffuser plate having a front surface defining a central aperture and arranged to conform with the baffle element, the baffle element being located against the diffuser plate; and a slinger element coupled to the shaft; the baffle element comprising: an inner portion defining a circular central opening positioned with a centre of the central opening on the longitudinal axis and the perimeter of the central opening lying in a plane transverse to the longitudinal axis; a wall upstanding from the front surface of the baffle element at a periphery of the inner portion of the baffle element; and at least two gutter surfaces extending radially-outwardly from the inner portion though respective gaps in the wall at different respective circumferential positions about the center of the central opening; the diffuser plate supporting the baffle element with the central opening of the baffle element in register with the central aperture of the diffuser plate and in a fixed angular position about the central aperture of the diffuser plate.

13. The turbomachine of claim 12, further comprising a turbine housing which houses a turbine wheel, the turbine housing comprising: a gas inlet; an annular passageway from the gas inlet to the turbine wheel and defined between mutually facing radial walls; a plurality of vanes in the passageway arranged to deflect gas flowing through the passageway towards the direction of rotation of the turbine wheel; and a geometry variation mechanism for varying the relative positions of the radial walls and/or the vanes.

14. The turbomachine of claim 12, wherein the turbomachine is a turbocharger.

15. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] A non-limiting embodiment of the present disclosure will now be described, for the sake of example only, with reference to the following figures, in which:

[0033] FIG. 1 is a cross-sectional drawing of a known turbocharger;

[0034] FIG. 2 is composed of FIG. 2(a) which is a perspective view of an embodiment of the present disclosure which is baffle element, and FIG. 2(b) which is a perspective cut-away view of the baffle element;

[0035] FIG. 3 is an exploded view of a seal system comprising the baffle element of FIG. 2, an oil slinger element, and a diffuser plate which is a further embodiment of the present disclosure;

[0036] FIG. 4 is composed of FIG. 4(a) which is a side view of the slinger element of FIG. 2, and FIG. 4(b) which is a perspective cut-away view of the slinger element;

[0037] FIG. 5 is a perspective view of the assembled seal system;

[0038] FIG. 6 is composed of FIGS. 6(a) and 6(b) which are different cross-sectional views of the assembled seal system;

[0039] FIG. 7 is a perspective cut-away view of the assembled seal system;

[0040] FIG. 8 is a view of a seal plate of the bearing housing;

[0041] FIG. 9 is a rear view of the baffle element of FIG. 2;

[0042] FIG. 10 is composed of FIG. 10(a) which is a cross-sectional view of the baffle element of FIGS. 2, and 10(b) which is a side view of the baffle element of FIG. 2;

[0043] FIG. 11 is a view of the front surface of the diffuser plate of FIG. 3; and

[0044] FIG. 12 is a cross-sectional view of a portion the bearing housing of a turbomachine including the seal system of FIG. 3.

DETAILED DESCRIPTION

[0045] Embodiments of the present disclosure will now be described which are seal systems, or elements of seal systems, or turbomachines incorporating the seal systems. In particular, the turbomachine may be a turbomachine of a variable geometry type. The turbomachine may be a turbocharger which, apart from the seal system, is of the known type described above in relation to FIG. 1, and elements of FIG. 1 which appear in other figures of this specification are given the same reference numerals.

[0046] Referring firstly to FIG. 2(a), a baffle element 100 is shown which is an embodiment of the present disclosure. FIG. 2(b) is a perspective view of the baffle element with a section cut-away.

[0047] The baffle element comprises a central circular aperture 101 having a perimeter which is a circular rim 102. The perimeter of the central circular aperture 101 lies in a plane (the “plane of the circular aperture”). In use, the baffle element is placed with the plane of the circular aperture transverse to the rotational axis of a turbomachine (indicated as 25 in FIG. 1 and FIG. 12 below), with the rotational axis passing through the center of the circular aperture 101. The word “circumferential” is used in this document to refer to differences in angular position about the axis 25.

[0048] The surface of the baffle element 100 which faces in one direction along the axis 25, and which is generally the surface which is visible in FIG. 2(a), is referred to as the “front surface.” This faces towards the middle of the bearing chamber. When the seal system is employed in a turbocharger, the front surface faces towards the turbine. The opposite surface of the baffle element, which faces in the opposite direction along the axis 25 is referred to as the “rear surface,” and faces away from the bearing chamber and the turbine. When the seal system is employed in a turbocharger, the rear surface faces away from the turbine.

[0049] The circular aperture 101 is defined by an annular inner portion 103 of the baffle element, which is illustrated in FIG. 2(a) as flat and circularly symmetric. At the periphery of the inner portion 103 is a channel 104. That is, a region where the front surface of the baffle element 100 is recessed (i.e., rearward compared to the plane of the circular aperture). Radially outward of the channel 104 is a wall 105 composed of two portions 106, 107. The wall portions 106, 107 are circumferentially spaced (i.e., there are circumferential gaps 108, 109 between them). Within the circumferential gaps are respective gutter surfaces 110, 111 which are portions of the front surface of the baffle element 100. The gutter surfaces 110, 111 are typically mirror symmetric about respective planes including the axis 25 which pass through centers of the gutter surfaces 110, 111 (and the centers of the gaps 108, 109). The radial planes are mutually spaced apart by an angle about the axis 25 which may be at least 70 degrees, or at least 90 degrees, and may be no more than 130 degrees or no more than 120 degrees. A preferred range is from 90 to 120 degrees.

[0050] The gutter surface 110 is inclined plane of the circular aperture (i.e., to the axis 25) whereas the gutter surface 111 lies substantially in the plane of the circular aperture (i.e., it is orthogonal to the axis 25). In fact, as is visible in FIG. 2(b), the gutter surface 108 is very slightly inclined to the circular aperture (i.e., its radially outward portion is shown as very slightly rearward of the radially inner portion).

[0051] FIG. 3 shows a seal system comprising the baffle element 100 of FIG. 1, together with a diffuser plate 200 and an oil slinger element 300. In use, the seal system is provided within a bearing housing of the turbomachine, at one end of a bearing chamber. The slinger element 300 is fast with a rotating shaft of the turbomachine which rotates about the axis 25 with respect to the bearing housing, and the baffle element 100 is supported by the diffuser plate 200 at a fixed rotational position about the axis 25. The diffuser plate 200 in turn is fast with the seal plate of the bearing housing.

[0052] FIG. 4(a) is a side view of the slinger element 300, and FIG. 4(b) is a perspective cut-away view of the slinger element bisected by a plane including the rotational axis 25. The slinger element is circularly symmetric about an axis which in use coincides with the rotational axis 25. It includes a first radially extending ridge 301 which in use is inserted through the circular aperture 101 of the baffle element 100, and second radially extending ridge 302 which in use is faced by the rear surface of the baffle element 100. The second ridge 302 extends radially further from the axis 25 than the first ridge 301.

[0053] FIG. 5 is a perspective view of the seal system of FIG. 2 in an assembled configuration. FIGS. 6(a) and 6(b) are respective cross-sections of the assembled seal system, respectively in the planes marked as A-A and B-B in FIG. 5.

[0054] Note that the channel 104 is visible at the top of FIGS. 6(a) and 6(b), but substantially does not exist in the lower part of FIG. 6(a) and is shallow in the lower part of FIG. 6(b). To express this more specifically, FIGS. 6(a) and 6(b) indicate the depth d of the channel 104 for the circumferential position corresponding to the top of the figures. This is the maximum distance by which any point on the front face of the baffle at this circumferential position is recessed (i.e., rearward) of the plane of the circular aperture (indicated by the dashed line 115). It will be seen that this distance d is greater than the depth of the channel at the circumferential positions of the gutter surfaces 110, 111 (i.e., respectively in the lower part of FIG. 6(a) where d is substantially zero, and the lower part of FIG. 6(b)).

[0055] FIG. 7 is a cut-away perspective view of the assembled seal system, where the portion of the seal system to one side of the plane A has been removed.

[0056] FIG. 8 shows a seal plate 400 which is the portion of the bearing housing at one end of the bearing chamber. It includes a central aperture 401, surrounded by a contoured surface which is adapted to receive the rear face of the diffuser plate 200. The seal plate 400 is provided with apertures 402, 403 for fastening the diffuser plate 200 to the seal plate 400.

[0057] FIG. 9 is a rear view of the baffle element 100. FIG. 10(a) shows a cross-section of the baffle element 100 in the plane marked as Z-Z in FIG. 9. FIG. 10(b) shows a view of the baffle element 100 looking in the direction marked as C in FIG. 9.

[0058] FIG. 11 is a view of the front face of the diffuser plate 200. The diffuser plate 200 defines a central aperture 201. It includes forwardly-projecting circumferentially elongate protrusions 202, 203 which are shaped to rest in use against a circumferentially elongate portion of the rear surface of the wall 106 of the baffle element 100, and a forwardly projecting elongate protrusion 204 which is positioned to rest against a circumferentially elongate portion of the rear surface of the wall 107 of the baffle element. The elongate protrusions 202, 203, 204 are in use radially outward of the corresponding walls 106, 107 of the baffle element, and help to retain the baffle element in a fixed position relative to the diffuser plate 220. Two circumferential gaps 208, 209 defined respectively between the protrusions 202 and 204, and protrusions 203 and 204, correspond in angular position to respective ones of the gutter surfaces 110, 111. Interaction between the rear surface of the baffle element 100 and the protrusions 202, 203, 204, particularly the portions of the protrusions at each side of the gaps 208, 209, may at least assist in fixing the angular position of the baffle element 100 about the axis 25.

[0059] Finally, FIG. 12 shows is cross-section a portion of a turbomachine which is an embodiment of the present disclosure. The turbomachine may be a turbocharger (e.g., a variable geometry turbocharger), which is identical to the known turbocharger shown in FIG. 1, except that the seal system which is provided between the bearing chamber 22 and the compressor wheel 6 takes the form described above and illustrated with respect to FIGS. 2 to 11. The drain 20 is positioned, in the case shown in FIG. 12, such that the direction of gravity is the direction from the shaft 8 to the drain 20 (i.e., the top to bottom direction in FIG. 12). The gutter surface 111 projects radially from the axis 25 substantially in the direction of gravity and directs oil on the front surface of the baffle element 110 to the drain 20.

[0060] Note however, that the turbocharger could also be positioned in a different orientation in which, compared to the configuration of FIG. 12, it is rotated about the axis 25 such that a second drain of the bearing housing (not shown in FIG. 12 because it is out of the plane of the diagram) is spaced in the direction of gravity from the shaft 8. In this case, the gutter surface 110 may be directed generally downwardly from the axis 22, so that the gutter surface 110 is positioned to direct oil on the front surface of the baffle element 110 to the second drain. Note that optionally the first drain 20 and drain may be respective drain portions of a single aperture in the bearing housing, circumferentially displaced from each other about the axis 25.

[0061] Note that typically the two possible orientations of the turbocharger are about 90 degrees apart about the rotational axis 25, but the respective central planes of the gutter surfaces 110, 111 may not be 90 degrees apart about the axis 25, to take into account other constraints on the baffle element design, such as wall thickness, strength, etc., as well as the feasibility of assembling the turbocharger. The angle between the central planes of the gutter surfaces 110, 120 may for example be in the angular range of 90-120 degrees, as mentioned above.

[0062] Thus, the seal system may be operative to direct oil from the front surface of the baffle element to a respective one of the two drains (or two drain portions) irrespective of whether the gutter surface 110 or the gutter surface 111 extends generally downward (i.e., generally in the direction of gravity) from the axis 25. Thus, the turbocharger containing the bearing housing depicted in FIG. 12 can be used in either of these two configurations.

[0063] A number of variations are possible within the scope of the present disclosure as defined by the claims. For example, in the embodiment described one gutter surface 110 is inclined to the axis (i.e., a normal direction to the gutter surface is neither at an angle of substantially zero nor an angle of substantially 90 degrees with respect to the axis 25), and the other gutter surface 111 is transverse to the axis 25. However, in a variation both of the gutter surfaces may be inclined to the axis 25, or both may be transverse to it.

[0064] In another example, although in the embodiment depicted the gutter surfaces 110, 111 are mutually circumferentially displaced by an angle of about 120 degrees, in variations the circumferential spacing between the gutter surfaces 110, 111 may be greater or less than this. For example, it may be about 90 degrees.