Bearing ring with integrated cooling channels

Abstract

The invention relates to a bearing ring (10) with integrated cooling channels (11, 12, 13).

Description

[0001] Bearing ring with integrated cooling channels

[0002] The invention relates to a bearing ring with integrated cooling channels.

[0003] Bearing rings in aircraft engines are generally exposed to high rolling loads and high operating temperatures. This is especially true for bearing rings in main shaft bearings. The materials used for such bearing rings are predominantly heat-resistant, through-hardening or case-hardened steels, such as M50 (AMS 6491), M50NiL (AMS 6278), RBD, and Pyrowear 675 (AMS 5930).

[0004] Heat dissipation from the contact areas is achieved by a continuous oil flow. Improved heat dissipation from the contact area can increase bearing performance, for example in the engine sector. Such heat dissipation is known, for example, from EP 2 503 107 B1, which describes a bearing arrangement for a turbomachine, wherein a bearing housing part is provided with a coolant channel and a bearing housing part is provided with a lubricant channel, the coolant channel and the lubricant channel being fluidically separated from one another. Specifically, a material composite comprising a bearing housing with integrated cooling channels in combination with a bearing shell is described.

[0005] However, since the fatigue strength of the aforementioned heat-resistant steels decreases with increasing temperature and the operating temperature below which the oils used for lubrication and heat dissipation can be used is also limited, a higher temperature in the contact area cannot be permitted with the bearing materials and oils currently used.

[0006] In principle, heat dissipation from the contact area is possible, for example, in EP 2 503 107 B1. However, the cooling possibilities are limited because the channels through which the coolant flows are located farther than desired from the contact surface, as the bearing shell must have a certain minimum thickness for strength reasons. Furthermore, the production of the described composite is problematic. Furthermore, the introduction of the cooling channels on the inner diameter of the inner ring or the outer diameter of the outer ring influences the existing fit conditions, for example, with regard to strength and differential expansion of the mating parts.

[0007] DE 10 2014 216 313 A1 describes a bearing ring with internal channels integrated near the raceway and with a cross-sectional shape that deviates from circular. The cross-sectional shape can therefore be adapted to the shape of the bearing ring.

[0008] US 4 129 344 describes a rolling bearing ring in whose raceway grooves for the transport of lubricant are arranged, which run obliquely to the bearing axis.

[0009] Highly stressed rolling bearings are used in highly stressed rolling bearings, such as those found in aircraft engines. The aim of the invention is to further optimize the dissipation of frictional heat from the rolling contact.

[0010] The problem is solved by a bearing ring according to patent claim 1.

[0011] The core concept of the invention is the branching of a cooling channel geometry within a bearing ring. Cooling fluid first builds up a uniform pressure in a circumferential distribution channel and then flows through smaller, essentially axially extending channels, which in turn flow into a circumferential collecting channel.

[0012] The bearing ring according to the invention comprises at least one distribution channel extending in the circumferential direction, at least one collecting channel extending in the circumferential direction, and several transverse channels, each connecting the distribution channel to the collecting channel. The cross-sectional area of ​​the transverse channels is smaller than the cross-sectional area of ​​the distribution channel and the cross-sectional area of ​​the collecting channel.

[0013] The bearing ring according to the invention is preferably an outer ring, for example, of an engine, for example an aircraft engine. In a preferred embodiment, at least one of the transverse channels has a curved profile relative to the axial direction. As a result, such a curved transverse channel is consistently close to the raceway of the bearing ring over its entire length, allowing cooling fluid flowing through it to dissipate heat from the raceway even more effectively.

[0014] In a further preferred embodiment, at least one of the transverse channels has a course that deviates from an axially parallel orientation. As a result, the effective length of the transverse channel is greater than the radial distance between the distribution channel and the collection channel. This leads to improved heat dissipation, since the cooling fluid flows through the transverse channel over a longer period of time.

[0015] Further preferably, at least one of the transverse channels has a cross-sectional shape deviating from a circular shape and can, for example, have a circular ring section shape.

[0016] Particularly preferred is a cross-section that extends in an arcuate shape similar to the raceway to be cooled, i.e., it is more or less conforming to the raceway shape. This shape increases the heat transfer between the cooling channel and the raceway. This inevitably also improves the load-bearing capacity of the bearing comprising the bearing ring according to the invention with regard to speed, load capacity, and temperature range.

[0017] In a further preferred embodiment, the channel cross-section can vary in shape and surface area along its entire length, thereby influencing the heat exchange surface, the heat transfer coefficient, and the flow rate of the coolant. This targeted influencing of heat transfer in the circumferential direction can have a beneficial effect on the dissipation of heat losses in the circumferential load zone, which is particularly pronounced in radially loaded rolling bearings. Furthermore, by varying the cross-sectional shapes and surface areas in the circumferential direction, special requirements regarding the structural strength of the rings can be taken into account. The bearing ring according to the invention can be manufactured using 3D printing.

[0018] Due to the cooling channel geometry, the introduced cooling fluid first builds up a uniform pressure in the circumferential distribution channel before flowing through the smaller cross-section transverse channels and finally into the collecting channel. This flow behavior allows the required pump power and the required cooling fluid quantity to be reduced.

[0019] Description of the characters

[0020] Figure 1 shows a cross section through a bearing ring 10 according to the invention, namely here an outer ring, with a distribution channel 11 running in the circumferential direction and a collecting channel 12 running in the circumferential direction. Between the distribution channel 11 and the collecting channel 12, a plurality of transverse channels 13 are arranged which connect them and which have a significantly smaller cross section than the distribution channel 11 and the collecting channel 12.

[0021] In Figure 1, these transverse channels 13 run in an axis-parallel direction perpendicular to the radial direction.

[0022] In a further embodiment, shown in Figure 2, the transverse channels are curved relative to the axial direction according to the contour of the raceway 14 of the bearing ring 10.

[0023] In a further embodiment shown in Figure 3, the orientation of the transverse channels deviates from an axial direction. The transverse channels can have a contour-like curvature, as shown here. However, this orientation is also conceivable for transverse channels that are not curved in the axial direction (not shown here). Reference symbol Bearing ring Distribution channel Collecting channel Transverse channel Raceway

Claims

Patent claims 1. Bearing ring (10) comprising at least one distribution channel (11) running in the circumferential direction at a distance from a raceway (14) of the bearing ring (10), at least one collecting channel (12) running in the circumferential direction at a distance from the raceway (14), a plurality of transverse channels (13) arranged at a distance from the raceway (14), each connecting the distribution channel (11) to the collecting channel (12), wherein the cross-sectional area of the transverse channels (13) is smaller than the cross-sectional area of the distribution channel (11) and the cross-sectional area of the collecting channel.

2. Bearing ring (10) according to claim 1, wherein the bearing ring (10) is a bearing outer ring.

3. Bearing ring (10) according to claim 1 or 2, wherein at least one of the transverse channels (13) has a curved course relative to the axial direction.

4. Bearing ring (10) according to one of claims 1 to 3, wherein at least one of the transverse channels (13) has a course which deviates from an axially parallel orientation.

5. Bearing ring (10) according to one of claims 1 to 4, wherein at least one of the transverse channels (13) has a cross-sectional shape deviating from a circular shape.

6. Bearing ring (10) according to one of claims 1 to 5, characterized in that the cross-sectional shape of at least one of the transverse channels (13) changes along its course.

7. Bearing comprising a bearing ring (10) according to one of claims 1 to 6.

8. Engine comprising a bearing with a bearing ring (10) according to one of claims 1 to 6.

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