CH717468B1 - Axial bearing for a shaft, in particular an axial turbocharger. - Google Patents

Abstract

The invention relates to an axial bearing (1) for a shaft, in particular an axial turbocharger, with a thrust bearing (3) for stationary fixing of the axial bearing (1) and a rotatable race (4) for receiving the shaft, which has a radial running surface (5) is accommodated in the thrust bearing (3), the thrust bearing (3) and the raceway (4) each having an axial sliding surface (31, 41), wherein between the two axial sliding surfaces (31, 41) a freely rotatable bearing disc (6) is arranged, wherein the bearing disc (6) is rotatably arranged with a radial inner surface (7) on the radial running surface (5) of the race (4) and the radial inner surface (7) has at least one axial groove (9) for guiding a lubricant ( 11), and wherein the radial running surface (5) in the region of the bearing disc (6) has at least one further axial groove (10) for guiding the lubricant (11).

Description

The invention relates to an axial bearing for a shaft, in particular an axial turbocharger, with a thrust bearing for stationary fixing of the thrust bearing and a rotatable race for receiving the shaft, which is accommodated with a radial running surface in the thrust bearing.

In axial turbochargers, the axial bearing for absorbing high axial thrust usually consists of a stationary thrust bearing, a freely rotating bearing disk and a race rotating with the rotor speed. The bearing disk is double-acting and has a sliding surface both for the non-rotating thrust bearing and for the rotating race. The speed of the bearing washer is based on the axial friction conditions of the sliding surfaces. The bearing disk rotates on a radial oil film of the raceway and is therefore radially mounted. The disadvantage of this is that this radial bearing tends to be unstable. The oil supply to the bearing side or the sliding surface between the race and the bearing disk is provided by axial profiling in the rotating bearing disk. Due to a high speed difference between the race and the bearing disk as well as a radial speed component, detachment occurs in areas of the axial profiling of the bearing disk and thus insufficient lubrication on the radial running surface or the sliding surface between the race and bearing disk.

It is therefore an object of the present invention to provide an axial bearing for a shaft, in particular an axial turbocharger, which improves the lubrication of the sliding surface between the race and the bearing disk.

[0004] This object is achieved by the combination of features according to patent claim 1.

According to the invention, an axial bearing for a shaft, in particular an axial turbocharger, is proposed with a thrust bearing for stationary fixing of the axial bearing and a rotatable race for receiving the shaft, which is accommodated with a radial running surface in the thrust bearing. The thrust bearing and raceway each have an axial sliding surface, and a freely rotatable bearing washer is disposed between the two axial sliding surfaces. Furthermore, the bearing disc is rotatably arranged with a radial inner surface on the radial running surface of the race and the radial inner surface comprises at least one axial groove for guiding a lubricant. In addition, the radial running surface in the area of the bearing disk has at least one further axial groove for guiding the lubricant.

The advantage of this is that the instability caused by a radial velocity component of the lubricating film is reduced by reducing the profile depth in the rotating bearing disc. The axial grooves of the race form a carrier film structure for the lubricant of the rotating bearing disc and part of the axial oil supply for the axial sliding surface of the race. In this way, the lubrication of the sliding surface between the race and the bearing disk is improved.

In an advantageous embodiment of the invention it is provided that the at least one axial groove in the radial inner surface and the at least one further axial groove in the radial tread have a partially circular or partially elliptical cross-section. Due to the part-circular or part-elliptical cross-section, a flow of the lubricant in the direction of the raceway and bearing disk or a supply of the corresponding sliding surface is optimized.

The axial bearing is preferably designed such that an area ratio of a cross-sectional area of the at least one further axial groove in the radial running surface to the at least one axial groove in the radial inner surface is 0.1 to 0.7. Since a lubricant consumption of the axial sliding surface between the race and the bearing disk corresponds to a shaft speed or a bearing disk speed of the respective application, in particular of the respective axial turbocharger, by adapting the area ratio of a cross-sectional area of the at least one further axial groove in the radial running surface to the at least one axial groove in the radial inner surface to improve lubrication.

In one embodiment of the invention it is provided that the at least one axial groove in the radial inner surface of the bearing disc and the at least one further axial groove in the radial running surface are inclined at an angle of 0° to 45° with respect to a rotational axis of the axial bearing or run obliquely to it. The axial lubricant supply is influenced by an inclination or an oblique course and can be adapted to a shaft speed or a bearing disk speed of the respective application, in particular of the respective axial turbocharger, and thus optimized.

Furthermore, an embodiment is favorable in which a longitudinal extension of the at least one further axial groove of the raceway in an axial direction of the axial bearing corresponds to an extension of the bearing washer in the axial direction. In this way, the at least one further groove of the bearing ring is arranged precisely in the area that is particularly important for lubrication, since that is where the bearing washer is positioned.

In a further advantageous embodiment, the invention provides that the thrust bearing, the race and the bearing washer are made of a ferrous material.

In addition, a variant of the invention is favorable, in which the bearing disc and the raceway are hardened, coated or untreated. It is favorable that the bearing disk and the raceway can be adapted to the respective application of the axial bearing, in particular to the respective axial turbocharger, and an associated degree of purity of the lubricant.

The axial bearing according to the invention is designed in an advantageous embodiment such that the thrust bearing has a lubricant supply for the lubricant for lubricating the radial running surface of the race and the two axial sliding surfaces integrally, preferably via a lubricant channel. The advantage of a lubricant supply that is integral in the thrust bearing is that the thrust bearing is a stationary or fixed component when the axial bearing is in a mounted state. As a result, the supply of lubricant to the axial bearing can be integrated particularly easily into an existing lubricant circuit.

In a preferred embodiment of the invention, an outlet opening of the lubricant supply is arranged on the front side towards the running surface of the raceway. As a result, the lubricant enters the axial bearing at a point where it can be directed particularly favorably to the sliding surface between the thrust bearing and the bearing disk or the sliding surface between the race and the bearing disk or distributed between the two sliding surfaces.

In a further advantageous embodiment, the invention provides that a gap is formed between the radial inner surface and the radial running surface. Furthermore, a groove depth of at least the at least one axial groove in the radial inner surface and/or the at least one further axial groove in the radial running surface is designed to be greater in the radial direction than a gap width of the gap.

According to the invention, an axial turbocharger with at least one axial bearing with the features described above is also proposed, which comprises a shaft which is rotatably accommodated in the at least one axial bearing. The advantage of this is that the supply of lubricant to the axial bearing of the axial turbocharger is improved by means of the grooves arranged in the race and in the rotating bearing disk.

In an advantageous embodiment of the invention it is provided that the axial turbocharger has a housing and the respective thrust bearing is fixed to the stationary fixing of the respective axial bearing on the housing. As a result, the axial bearing is integrated and fixed in the axial turbocharger.

Other advantageous developments of the invention are characterized in the subclaims or are shown in more detail below together with the description of the preferred embodiment of the invention with reference to the figures. 1 shows a sectional view of an axial bearing for a shaft of an axial turbocharger, FIG. 2 shows a cross section of the axial bearing for a shaft of an axial turbocharger, and FIG. 3 shows a sectional view of a race of the axial bearing for a shaft of an axial turbocharger.

In Figure 1 is a sectional view of an axial bearing 1 is shown for a shaft of an axial turbocharger. The axial bearing 1 comprises a thrust bearing 3 for stationary fixing of the axial bearing 1 and for absorbing an axial thrust acting on the axial bearing 1 . In addition, the axial bearing 1 has a rotatable race 4 for receiving the shaft, which is received with a radial running surface 5 in the thrust bearing 3 .

The thrust bearing 3 includes an integral lubricant supply 12 for a lubricant 11 for lubricating the radial running surface 5 of the race 4 and the two axial sliding surfaces 31, 41, which have the thrust bearing 3 and the race 4, via a lubricant channel. The outlet opening of the lubricant supply 12 is arranged on the front side towards the running surface of the raceway 4 .

During operation of the axial turbocharger, the axial bearing 1 rotates about an axis of rotation RA and the lubricant 11 runs along the direction of the arrow.

Furthermore, a freely rotatable bearing disc 6 is positioned between the two axial sliding surfaces 31,41. The bearing disk 6 is rotatably arranged with a radial inner surface 7 on the radial running surface 5 of the running ring 4 and the radial inner surface 7 includes an axial groove 9 for guiding a lubricant 11. In addition, the radial running surface 5 in the area of the bearing disk 6 has another axial groove 10 for guiding the lubricant 11 on. A longitudinal extension of the additional axial groove 10 in an axial direction of the axial bearing 1 corresponds to an extension of the bearing washer 6 in the axial direction.

The thrust bearing 3, the race 4 and the bearing washer 6 of the thrust bearing 1 are made of a ferrous material. In addition, the bearing disk 6 and the raceway 4 are coated.

Figure 2 shows a cross section of the axial bearing 1 shown in Figure 1 for a shaft of an axial turbocharger. The axial groove 9 in the radial inner surface 7 and the further axial groove 10 in the radial running surface 5 have a part-circular cross section. Furthermore, an area ratio of a cross-sectional area of the further axial groove 10 in the radial running surface 5 to the axial groove 9 in the radial inner surface 7 is approximately 0.3.

Furthermore, a gap 13 is formed between the radial inner surface 7 and the radial running surface 5 . In this case, a groove depth of the axial groove 9 in the radial inner surface 7 and of the further axial groove 10 in the radial running surface 5 is greater in the radial direction than a gap width of the gap 13.

FIG. 3 shows a sectional view of the race 4 of the axial bearing 1 for a shaft of an axial turbocharger, which shows that the further axial groove 10 in the radial running surface 5 is at an angle of 40° with respect to the axis of rotation RA of the axial bearing 1 is inclined or runs obliquely thereto.

Reference List

1 axial bearing 3 thrust bearing 31 axial sliding surface 4 race 41 axial sliding surface 5 radial running surface 6 bearing washer 7 radial inner surface 9 axial groove 10 further axial groove 11 lubricant 12 lubricant supply 13 gap

Claims (12)

1. Axial bearing (1) for a shaft, in particular an axial turbocharger, with a thrust bearing (3) for stationary fixing of the axial bearing (1) and a rotatable race (4) for receiving the shaft, which has a radial running surface (5) in the thrust bearing (3) is accommodated, wherein the thrust bearing (3) and the raceway (4) each have an axial sliding surface (31, 41), a freely rotatable bearing disc (6) being arranged between the two axial sliding surfaces (31, 41), wherein the bearing disc (6) is rotatably arranged with a radial inner surface (7) on the radial running surface (5) of the race (4) and the radial inner surface (7) comprises at least one axial groove (9) for guiding a lubricant (11). , and wherein the radial running surface (5) in the region of the bearing disc (6) has at least one further axial groove (10) for guiding the lubricant (11). 2. Axial bearing (1) according to claim 1, characterized in that the at least one axial groove (9) in the radial inner surface (7) and the at least one further axial groove (10) in the radial running surface (5) have a part-circular or part-elliptical have cross section. 3. Axial bearing (1) according to claim 1 or 2, characterized in that an area ratio of a cross-sectional area of the at least one further axial groove (10) in the radial running surface (5) to the at least one axial groove (9) in the radial inner surface ( 7) is 0.1 to 0.7. 4. Axial bearing (1) according to any one of claims 1 to 3, characterized in that the at least one axial groove (9) in the radial inner surface (7) of the bearing disc (6) and the at least one further axial groove (10) in the radial running surface (5) are inclined at an angle of 0° to 45° with respect to an axis of rotation of the axial bearing (1) or run obliquely thereto. 5. Axial bearing (1) according to one of the preceding claims, characterized in that a longitudinal extension of the at least one further axial groove (10) in an axial direction of the axial bearing (1) corresponds to an extension of the bearing washer (6) in the axial direction. 6. Axial bearing (1) according to any one of the preceding claims, characterized in that the thrust bearing (3), the race (4) and the bearing disc (6) are made of a ferrous material. 7. Axial bearing (1) according to any one of the preceding claims, characterized in that the bearing disc (6) and the raceway (4) are hardened, coated or untreated. 8. Axial bearing (1) according to one of the preceding claims, characterized in that the thrust bearing (3) has a lubricant supply (12) for the lubricant (11) for lubricating the radial running surface (5) of the race (4) and the two axial sliding surfaces (31, 41) integrally, preferably via a lubricant channel. 9. An axial bearing (1) according to claim 8, characterized in that an outlet opening of the lubricant supply (12) is arranged on the front side towards the running surface of the raceway (4). 10. Axial bearing (1) according to one of the preceding claims, characterized in that a gap (13) is formed between the radial inner surface (7) and the radial running surface (5), wherein a groove depth of at least the at least one axial groove (9) in the radial inner surface (7) and/or the at least one further axial groove (10) in the radial running surface (5) is formed larger in the radial direction than a gap width of the gap (13). 11. Axial turbocharger with at least one axial bearing (1) according to one of the preceding claims, characterized in that the axial turbocharger comprises a shaft which is rotatably accommodated in the at least one axial bearing (1). 12. The axial turbocharger as claimed in claim 11, characterized in that the axial turbocharger has a housing, the respective thrust bearing (3) being fastened to the housing for stationary fixing of the respective axial bearing (1).