Bearing assembly, in particular for an electric motor or for a transmission, and electric motor comprising such a bearing assembly
Patent Information
- Application Number
- EP2023809454
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-04-05
- Filing Date
- 2023-11-14
- Publication Date
- 2025-11-05
AI Technical Summary
Existing bearing arrangements in electric motors and gearboxes face challenges in achieving effective lubrication, leading to increased power loss and potential oil ingress into the engine's interior.
A bearing arrangement with a hollow flange part that includes a first and second shaft sealing ring, allowing for the creation of an oil-filled space for lubrication, where the lubricant is an oil-air mixture, and an annular gap to prevent oil from reaching the second shaft seal, reducing power loss and preventing oil ingress into the engine.
The solution enables efficient lubrication with reduced power loss and prevents oil from entering the engine's interior, maintaining a sealed environment and optimizing lubricant composition for reduced friction losses.
Smart Images
Figure 1.1
Abstract
Description
[0001] BEARING ARRANGEMENT, IN PARTICULAR FOR AN ELECTRIC MOTOR OR FOR A GEARBOX, AND ELECTRIC MOTOR WITH SUCH BEARING ARRANGEMENT
[0002] Description:
[0003] The invention relates to a bearing arrangement, in particular for an electric motor or for a transmission, and to an electric motor with a bearing arrangement.
[0004] It is common knowledge to support a shaft using a bearing.
[0005] From DE 10 2017213 081 A1, a powershift transmission is known as the closest state of the art.
[0006] A coupling adapter is known from EP 2 735 774 A1.
[0007] An AC motor is known from EP 0 656 680 A1 as a traction drive.
[0008] An electric motor is known from DE 10 2008 028 622 A1.
[0009] An electric motor with a sensor is known from DE 10 2008 661 A1.
[0010] A liquid jet flow rectifier vessel is known from DE 938 140 B.
[0011] From DE 32 11 715 A1 a pressure-lubricated rolling bearing arrangement for the shaft of a closed electrical machine is known.
[0012] From DE 91 03 935 U1 a bearing housing for a multi-row rolling bearing or for several coaxially adjacent rolling bearings is known.
[0013] The invention is therefore based on the object of developing a bearing assembly in which improved lubrication should be possible. According to the invention, this object is achieved in the bearing assembly according to the features specified in claim 1 and in the electric motor according to the features specified in claim 15.
[0014] Important features of the invention in the bearing arrangement, in particular for an electric motor or for a transmission, are that the bearing arrangement comprises a shaft, a flange part, a bearing accommodated in the flange part for rotatably supporting the shaft, a first shaft sealing ring and a second shaft sealing ring, wherein the flange part is hollow and the shaft projects through the flange part in the axial direction, wherein the first shaft sealing ring seals towards the shaft, in particular in that a sealing lip of the first shaft sealing ring touches the shaft and / or runs along a first sealing seat of the shaft, in particular which is machined by grinding, wherein the second shaft sealing ring seals towards the shaft, in particular in that a sealing lip of the second shaft sealing ring touches the shaft and / or runs along a second sealing seat of the shaft, in particular which is machined by grinding, wherein the first shaft sealing ring is separated from the second shaft sealing ring in the axial direction,in particular in the direction of the axis of rotation of the shaft, wherein the bearing is arranged in the axial direction between the first shaft sealing ring and the second shaft sealing ring, wherein the flange part has a first recess passing through the flange part for supplying lubricant, wherein the flange part has a second recess passing through the flange part for removing, in particular for discharging, lubricant, wherein the first recess is spaced from the second recess in the circumferential direction, in particular wherein the first recess is arranged diametrically opposite the second recess in the circumferential direction.
[0015] The advantage here is that a spatial area can be filled with lubricant, in particular a lubricant in the form of an oil-air mixture, wherein a bearing is arranged in the spatial area which can be supplied with the lubricant. The shaft seals seal off the environment. This means that an electric motor can be equipped with an A-side oil-lubricated bearing arrangement and the rotor shaft of the electric motor can be supported with low power losses. The flange part therefore functions as a bearing flange with an integrated oil-filled spatial area so that the bearing can be lubricated with oil, although no oil is allowed to get into the interior of the motor. For this reason, an axially elongated annular gap is arranged between the bearing and the second shaft seal so that oil can only reach the second shaft seal with difficulty. Additional internal grooves create a collection point for oil, in particular oil thrown off the shaft.
[0016] In an advantageous embodiment, the first shaft seal is accommodated in a bearing cover, which is tightly connected to the flange part, in particular by means of a flat gasket arranged between the flange part and the bearing cover. Advantageously, the space surrounding the bearing is sealed from the environment.
[0017] In an advantageous embodiment, the first shaft seal is housed in the flange part. This has the advantage that the space surrounding the bearing is sealed from the environment and can therefore be filled with oil. This reduces power loss.
[0018] In an advantageous embodiment, the second shaft seal is accommodated in the flange part. This is advantageous in that the space surrounding the bearing is sealed off from the interior of the electric motor. This prevents oil from penetrating the interior of the motor. In an advantageous embodiment, the first recess is arranged on the side of the bearing axially remote from the first shaft seal and the second recess is arranged on the side of the bearing axially facing the first shaft seal. This is advantageous in that the lubricant is admitted on the first axial side of the bearing and discharged on the other axial side of the bearing. This means that the lubricant must penetrate the bearing, especially when the lubricant is embodied as a mixture.
[0019] In an advantageous embodiment, an annular space is defined by the flange part, the first shaft seal, the second shaft seal, and the shaft, and is sealed from the external environment of the bearing assembly by means of the first shaft seal. Advantageously, the space can be supplied with a lubricant comprising a liquid, such as oil. However, the shaft seals seal the space from the environment, in particular both from the external environment and the interior of the electric motor.
[0020] In an advantageous embodiment, the bearing, in particular a rolling bearing, especially a ball bearing, is arranged in the spatial area. This is advantageous because efficient lubrication can be achieved using the lubricant. In particular, the proportion of air in the lubricant can be optimized. This reduces friction losses.
[0021] In an advantageous embodiment, the first recess opens into the annular space, particularly from the external environment. This is advantageous because the supply of lubricant can be carried out in a simple manner.
[0022] In an advantageous embodiment, the second recess opens into the annular space, particularly from the external environment. This is advantageous in that it allows lubricant to be released, particularly in the event of excess pressure. Preferably, the second recess is arranged below the first recess in the direction of gravity. In an advantageous embodiment, the lubricant is an oil-air mixture. This is advantageous in that power loss can be reduced and efficient, optimized lubrication is enabled.
[0023] In an advantageous embodiment, a radially projecting flange area is formed on the flange part, which has a through-bore that acts as an inlet for the lubricant, with a pipe leading from the inlet to the first recess. This is advantageous in that the flange area transmits a high reactive torque, and the inlet can be arranged at a large radial distance and thus easily accessible.
[0024] In an advantageous embodiment, the inlet is arranged at a greater radial distance than the first and second recess, wherein the inlet is spaced apart in the axial direction from the first recess and from the second recess, in particular
[0025] - wherein the flange area protrudes radially further than the connection area and / or wherein axially between the flange area and the connection area the flange part has a smaller outer diameter than in the flange area and than in the connection area.
[0026] The advantage here is that the inlet is easily accessible. This allows for a hose coming from the outside to be easily connected from the motor side. The flange section is narrowed from the inlet to the connection area. This narrowing can be bridged using a pipe that can be connected during the manufacture of the electric motor. This allows for a hose coming from the outside to be easily and easily connected, as it is connected from the motor side and not from the load side.
[0027] In an advantageous embodiment, the spatial area axially between the bearing and the second shaft seal has an annular gap, which is adjacent to a free space on both sides axially defined by an inner groove in the flange part. One advantage here is that a particularly thin oil drain hole can optionally be provided, which runs through the flange part and opens into one of the two free spaces. This allows any accumulating oil to flow away before it comes into contact with the second shaft seal. By making the annular gap as long as possible in the axial direction, the oil is effectively prevented from reaching the second shaft seal, or at least the amount of oil reaching the second shaft seal is kept to a minimum. This is because before the oil builds up to a dangerous level at the second shaft seal, it flows into the nearest inner groove.
[0028] In an advantageous embodiment, the maximum radial width of the annular gap is smaller than the maximum radial width of the respective free space. This has the advantage that flow through the annular gap is prevented or at least reduced.
[0029] In an advantageous embodiment, the inner ring of the bearing is axially positioned against a step on the shaft and is axially limited by a retaining ring embedded in an annular groove in the shaft. The advantage here is that the bearing can be designed as a fixed bearing.
[0030] In an advantageous embodiment, the outer ring of the bearing is axially positioned against a step of the flange portion on one side and is axially limited by the bearing cover on the other. The advantage here is that the bearing can be designed as a fixed bearing.
[0031] In an advantageous embodiment, the flange part has an annular bearing receiving area, the flange area, and a tubular area connected to the bearing receiving area and the flange area. It is advantageous that the tubular area can be designed to be elongated. In particular, the tubular area is axially wider than the clear inner diameter of the bearing seat, in particular than the clear inner diameter of the bearing receiving area. This makes it difficult for lubricant to penetrate towards the stator because the annular gap between the shaft and the tubular area can be designed to be very narrow. The second shaft seal also provides a seal. In an advantageous embodiment, the flange area is designed in the shape of a perforated disc.
[0032] The advantage here is that the shaft can be arranged so that it protrudes through the flange area and the tubular area as well as through the bearing receiving area.
[0033] In an advantageous embodiment, radially outwardly projecting ribs, which are particularly regularly spaced from one another in the circumferential direction, are formed on the tubular region and extend axially from the bearing support area to the flange area. This is advantageous in that it improves rigidity and heat dissipation. Thus, an electric motor encompassing the bearing assembly can be cooled more effectively.
[0034] In an advantageous embodiment, the flange part is formed integrally and / or in one piece with the bearing support area, the flange area, and the tubular area including the ribs. This is advantageous because it allows for simple production as a cast part, particularly a die-cast part.
[0035] In an advantageous embodiment, the tubular section is widened toward the flange area. This has the advantage that the outer diameter of the flange area can be selected to be very large, thus improving accessibility to the inlet.
[0036] In an advantageous embodiment, additional ribs are formed on the inside of the flange part. This has the advantage of enabling improved heat absorption and thus cooling.
[0037] In an advantageous embodiment, the area covered by the additional ribs in the axial direction encompasses the area covered by the flange part in the axial direction. This is advantageous because the additional ribs in the expanded area can be provided as inner ribs, thus achieving improved heat dissipation.
[0038] In an advantageous embodiment, the additional ribs are delimited radially inward by a radial distance that is greater than the radial distance of the inner wall of the bearing receiving area, in particular the bearing seat of the bearing in the bearing receiving area. It is advantageous that the shaft can be passed through the flange part.
[0039] In an advantageous embodiment, the flange part has an axially protruding annular collar on the side of the flange region axially remote from the bearing receiving region. On the outer circumference of the collar, protruding protrusions 33 are formed, in particular regularly spaced from one another in the circumferential direction and projecting in the radial direction, into each of which an axial bore is made, in particular for connection to a cuboid stator of an electric motor. The advantage here is that a cuboid stator can be connected even though the annular collar is shaped as a hollow cylinder. Thus, the hole pattern for fastening screws, which are screwed into the axial bores, can be arranged radially outside the annular collar.
[0040] Important features of the electric motor with bearing arrangement are that the shaft functions as the rotor shaft of the electric motor, in particular the shaft is the rotor shaft of the electric motor, in particular wherein the flange part is connected to a stator housing of the electric motor, which is connected on the side axially facing away from the flange part to a bearing shield in which a further bearing for the rotatable mounting of the shaft is accommodated.
[0041] The advantage here is that the bearing arrangement can be arranged on an electric motor and thus the losses due to the oil lubrication of the bearing of the bearing arrangement can be reduced.
[0042] Further advantages emerge from the dependent claims. The invention is not limited to the combination of features in the claims. Further possible combinations of claims and / or individual claim features and / or features of the description and / or the figures will become apparent to those skilled in the art, particularly from the problem and / or the problem posed by comparison with the prior art. The invention will now be explained in more detail with reference to schematic illustrations:
[0043] Figure 1 shows a bearing arrangement according to the invention in a sectional view.
[0044] Figure 2 shows an oblique view of a flange part 10 in a first viewing direction.
[0045] Figure 3 shows an oblique view of the flange part 10 in a second viewing direction.
[0046] As shown in the figures, the bearing arrangement according to the invention has a flange part 10, in particular a bearing flange, in which a bearing 11 is accommodated for the rotatable mounting of a shaft 1.
[0047] A bearing cap 3 is connected to the flange part 10, thereby covering the bearing from the outside environment. To ensure a tight connection, a flat gasket is preferably provided between the bearing cap 3 and the flange part 10.
[0048] A first shaft seal 2 is accommodated in the bearing cover 3 and seals against the shaft 1.
[0049] On the side of the bearing 11 axially facing away from the first shaft seal 2, a second shaft seal 6 is accommodated in the flange part 10, which seals towards the shaft 1.
[0050] This creates a sealed space around the bearing 11 into which lubricating oil can be admitted, which then lubricates the bearing 11.
[0051] The spatial area is thus limited by the bearing cover 3, the flange part 10, the first shaft seal 2 and the second shaft seal 6 as well as the shaft 1.
[0052] To avoid overpressure in this area, an outlet 12 is provided.
[0053] The outlet 12 is located on the underside of the flange part 10. A connection area 4 is located on the top side of the flange part 10. A radially protruding flange area 9 is also formed on the flange part 10, at which an inlet 7 is located.
[0054] The flange region 9 is spaced axially from the connection region 4. In particular, the flange region 9 protrudes radially from the flange part 10, in particular further than the connection region 4.
[0055] Axially between the flange area 9 and the connection area 4, the flange part 10 has a smaller outer diameter than in the flange area 9 and also than in the connection area 10.
[0056] A pipe 5 is connected to the connection area 4 and leads to an inlet 7 formed on the flange area 9. This inlet 7 is arranged at a greater radial distance than the connection area 4. This provides improved accessibility for connecting a supply line.
[0057] The radial distance is relative to the rotational axis of shaft 1. Likewise, the circumferential direction is relative to the rotational axis of shaft 1. The axial direction is parallel to the rotational axis of shaft 1.
[0058] An air-oil mixture is supplied to the bearing 11 through the inlet 7 and the pipe 5. This mixture is generated by injecting oil droplets into an air stream using an oil mixing device. The oil mixing device builds up the oil-air mixture to a corresponding pressure, so that it is then conveyed to the pipe. The oil-air mixture is forced through the pipe 5, which is so narrow, in particular has such a small inner diameter, that oil droplets are arranged one behind the other in the pipe 5, spaced apart from one another, with air being arranged between each oil droplet in the direction of the pipe 7.
[0059] The oil-air mixture travels from pipe 5 to bearing 11 and penetrates the bearing 11 as a mist, where the mist then condenses and lubricates the rolling elements of bearing 11. The speed of the oil-air mixture can be controlled at inlet 7 and / or by means of the pressure generated by the mixing device, which feeds inlet 7. This avoids flow-related losses and / or losses caused by high lubrication quantities.
[0060] The space also has an annular gap between the flange part 10 and the shaft 1, wherein the annular gap 10 is arranged axially between the bearing 11 and the shaft sealing ring 6.
[0061] The radial width of the annular gap has a constant area, which is axially bordered on both sides by a free space delimited by an inner groove of the flange part 10.
[0062] Preferably, a toothed part is connected to the shaft 1 in a rotationally fixed manner and the bearing arrangement is comprised by an electric motor, wherein the shaft 1 is the rotor shaft of the electric motor, or is comprised by a gearbox, wherein the shaft 1 is the input shaft of the gearbox.
[0063] As shown in Figures 2 and 3, the flange part 10 has an annular bearing receiving area 20 whose radial wall thickness is greater than the radial wall thickness of the flange part 10 in the area of the flange part 10 adjacent to the bearing receiving area 20.
[0064] Axially spaced from the bearing receiving area 20 is a flange area 9, the radial wall thickness of which is also greater than in the area of the flange part 10 adjacent to the bearing receiving area 20 and / or to the flange area 9, which is tubular in shape and connects the flange area 9 to the bearing receiving area 20.
[0065] On the outer circumference of the tubular area, ribs 21 projecting radially outwards and extending in the axial direction are formed, which enlarge the surface and thus improve the heat dissipation and also improve the rigidity of the flange part 10.
[0066] On the side of the flange region 9 axially remote from the bearing receiving region 20, the flange part 10 has an axially protruding annular collar 31, on the outer circumference of which are arranged, in particular, regularly spaced apart in the circumferential direction and protruding in the radial direction, each of which has an axial bore. Thus, a cuboid stator of the electric motor can be connected by means of screw parts, threaded rods, or screws screwed into the bores.
[0067] The ribs 21 are spaced apart from one another in the circumferential direction, in particular regularly.
[0068] Since the annular collar 31 has a smaller outer diameter than the flange area 9, the flange area projects beyond the annular collar 31 and also the hump areas 30 in the radial direction.
[0069] The tubular region preferably also has additional ribs on its inner side that extend axially and project radially inward, thus improving stability and heat dissipation. In particular, the heat dissipation of the stator winding of the electric motor is improved by the additional ribs that project radially inward.
[0070] The area covered by the additional ribs in the axial direction encompasses the area covered by the flange area 9 in the axial direction. In particular, this allows for stiffening of this area and improved heat dissipation.
[0071] The other ribs are limited radially inward by a radial distance that is greater than the radial distance of the bearing support.
[0072] The tubular area is widened towards the flange area.
[0073] The inlet 7 is formed on the flange area 9. The connection area 4 is formed on the bearing receiving area 20.
[0074] In further embodiments of the invention, a second bearing is arranged within the space, which is thus also lubricated by the oil-air mixture.
[0075] 1 wave
[0076] 2 shaft seal
[0077] 3 bearing caps
[0078] 4 Connection area
[0079] 5 Pipeline
[0080] 6 Shaft seal
[0081] 7 Entrance
[0082] 8 Connection area
[0083] 9 Flange area, annular
[0084] 10 Flange part, especially bearing flange
[0085] 11 camps
[0086] 12 Outlet
[0087] 20 Storage area
[0088] 21 ribs
[0089] 30 hump areas
[0090] 31 Ring collar
Claims
Patent claims:
1. Bearing arrangement, in particular for an electric motor or for a transmission, wherein the bearing arrangement comprises a shaft, a flange part, a bearing accommodated in the flange part for rotatably supporting the shaft, a first shaft sealing ring and a second shaft sealing ring, wherein the flange part is hollow and the shaft projects through the flange part in the axial direction, wherein the first shaft sealing ring seals towards the shaft, in particular in that a sealing lip of the first shaft sealing ring touches the shaft and / or runs along a first sealing seat of the shaft, in particular which is machined by grinding, wherein the second shaft sealing ring seals towards the shaft, in particular in that a sealing lip of the second shaft sealing ring touches the shaft and / or runs along a second sealing seat of the shaft, in particular which is machined by grinding, characterized in that the first shaft sealing ring is separated from the second shaft sealing ring in the axial direction,in particular in the direction of the axis of rotation of the shaft, wherein the bearing is arranged in the axial direction between the first shaft sealing ring and the second shaft sealing ring, wherein the flange part has a first recess passing through the flange part for supplying lubricant, wherein the flange part has a second recess passing through the flange part for removing, in particular for discharging, lubricant, wherein the first recess is spaced apart from the second recess in the circumferential direction, in particular wherein the first recess is arranged diametrically opposite the second recess in the circumferential direction.
2. Bearing arrangement according to claim 1, characterized in that the first shaft sealing ring is received in a bearing cover which is tightly connected to the flange part, in particular by means of a flat seal arranged between the flange part and the bearing cover or that the first shaft sealing ring is received in the flange part.
3. Bearing arrangement according to one of the preceding claims, characterized in that the second shaft sealing ring is received in the flange part.
4. Bearing arrangement according to one of the preceding claims, characterized in that the first recess is arranged on the side of the bearing axially facing away from the first shaft sealing ring and that the second recess is arranged on the side of the bearing axially facing the first shaft sealing ring.
5. Bearing arrangement according to one of the preceding claims, characterized in that an annular space region is delimited by the flange part, the first shaft sealing ring, the second shaft sealing ring and the shaft and is sealed from the external environment of the bearing arrangement by means of the first shaft sealing ring.
6. Bearing arrangement according to one of the preceding claims, characterized in that the bearing, in particular rolling bearing, in particular ball bearing, is arranged in the spatial area.
7. Bearing arrangement according to one of the preceding claims, characterized in that the first recess, in particular coming from the external environment, opens into the annular space region and / or that the second recess, in particular coming from the external environment, opens into the annular space region.
8. Bearing arrangement according to one of the preceding claims, characterized in that the lubricant is an oil-air mixture.
9. Bearing arrangement according to one of the preceding claims, characterized in that a radially projecting flange region is formed on the flange part, which has a through bore which acts as an inlet for the lubricant, wherein a pipe leads from the inlet to the first recess.
10. Bearing arrangement according to one of the preceding claims, characterized in that the inlet is arranged at a greater radial distance than the first and second recess, wherein the inlet is spaced apart in the axial direction from the first recess and from the second recess, in particular - wherein the flange region protrudes radially further than a connection region formed on the flange part and / or wherein axially between the flange region and the connection region the flange part has a smaller outer diameter than in the flange region and than in the connection region.
11. Bearing arrangement according to one of the preceding claims, characterized in that the space area axially between the bearing and the second shaft sealing ring has an annular gap, to which a free space delimited by an inner groove of the flange part 10 adjoins on both axial sides.
12. Bearing arrangement according to one of the preceding claims, characterized in that the maximum radial width of the annular gap is smaller than the maximum radial width of the respective free space.
13. Bearing arrangement according to one of the preceding claims, characterized in that the inner ring of the bearing is axially positioned on the one hand against a step of the shaft and on the other hand is axially delimited by a retaining ring embedded in an annular groove of the shaft, and / or that the outer ring of the bearing is axially positioned on the one hand against a step of the flange part and on the other hand is axially delimited by the bearing cover.
14. Bearing arrangement according to one of the preceding claims, characterized in that the flange part has an annular bearing receiving area, the flange area and a tubular area connected to the bearing receiving area and to the flange area, in particular wherein the flange area is designed in the shape of a perforated disc, wherein radially outwardly projecting ribs are formed on the tubular area, which ribs are spaced from one another in the circumferential direction, in particular regularly spaced from one another in the circumferential direction, and extend axially from the bearing receiving area to the flange area, in particular wherein the flange part is designed in one piece and / or in one part with the bearing receiving area, the flange area and the tubular area including the ribs, in particular wherein the tubular area is designed to be widened towards the flange area, and / or wherein further ribs are formed on the inner side of the flange part, in particular wherein the area covered by the further ribs in the axial direction comprises the area covered by the flange part in the axial direction, in particular wherein the further ribs are delimited radially inwardly by a radial distance which is greater than the radial distance of the inner wall of the bearing receiving area, in particular therefore of the bearing seat of the bearing in the bearing receiving area, in particular wherein on the side of the flange area axially facing away from the bearing receiving area the flange part has an axially projecting annular collar, on the outer circumference of which hump areas 33 are formed, in particular regularly spaced from one another in the circumferential direction and projecting in the radial direction, into each of which an axial bore is made, in particular for connection to a cuboid stator of an electric motor.
15. Electric motor with bearing arrangement according to one of the preceding claims, characterized in that the shaft functions as a rotor shaft of the electric motor, in particular the shaft is the rotor shaft of the electric motor, in particular wherein the flange part is connected to a stator housing of the electric motor, which is connected on the side axially facing away from the flange part to a bearing plate in which a further bearing for the rotatable mounting of the shaft is accommodated.