Motor bearing lubrication

Abstract

The invention relates to motor bearing lubrication. A motor includes a housing having a stator mounted to the housing. The drive shaft is rotatably mounted within the housing by a pair of bearing assemblies each including an inner bearing race and an outer bearing race. The rotor is mounted to the drive shaft. The driveshaft includes a longitudinal oil supply passage therein, the driveshaft including a first radial passage in communication with the longitudinal oil supply passage and extending to an inner race of a first of the pair of bearing assemblies and a second radial passage in communication with the longitudinal oil supply passage and extending to an inner race of a second of the pair of bearing assemblies. The inner races of the pair of bearing assemblies each include at least one lubrication bore.

Description

[0001] introduction

[0002] The information provided in this section is for the purpose of generally presenting the context of the present disclosure. To the extent described in this section, the works of the presently named inventors and aspects of the description that may not constitute prior art at the time of filing are neither explicitly nor implicitly admitted to be prior art to the present disclosure. Technical Field

[0003] The present disclosure relates to electric motors, and more particularly to improved motor bearing lubrication. Background Art

[0004] Motor bearing lubrication is an important part in the design of electric drive units. On the one hand, it is necessary to ensure that the bearings have sufficient lubrication to operate at the right temperature and to generate an oil film at the contact area. On the other hand, excess oil will increase churning losses and affect the efficiency of the motor. Traditionally, oil is supplied from the side of the motor bearing through the housing structure. The side supply of the motor housing will result in an oil bath at the lower bottom of the bearing, and the oil will diffuse through the movement of the bearing balls or rollers. This may result in excess oil at the bottom and much less oil at the loading area. Therefore, the present disclosure provides a more efficient way of motor bearing lubrication. Oil will be provided at the center of the shaft, and the oil will be delivered directly to the bearing contact surface by centrifugal force using holes at the raceway inside the bearing. Summary of the invention

[0005] Further areas of applicability of the present disclosure will become apparent from the detailed description, the claims and the accompanying drawings.The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

[0006] According to one aspect of the present disclosure, a motor includes a housing having a stator mounted to the housing. A drive shaft is rotatably mounted within the housing via a pair of bearing assemblies, each of the pair of bearing assemblies including an inner bearing race and an outer bearing race. A rotor is mounted to the drive shaft. The drive shaft includes a longitudinal oil supply passage therein, the drive shaft including a first radial passage communicating with the longitudinal oil supply passage and extending to an inner race of a first of the pair of bearing assemblies and a second radial passage communicating with the longitudinal oil supply passage and extending to an inner race of a second of the pair of bearing assemblies. The inner races of the pair of bearing assemblies each include at least one lubrication hole.

[0007] According to another aspect, the pair of bearing assemblies includes four contact points.

[0008] According to another aspect, the at least one lubrication hole is disposed between a pair of contact points of the inner race.

[0009] According to another aspect, the pair of bearing assemblies include angular contact points.

[0010] According to another aspect, the at least one lubrication hole is spaced apart from the contact point of the inner race.

[0011] According to another aspect, the at least one lubrication hole includes a plurality of lubrication holes.

[0012] According to another aspect, the pair of bearing assemblies includes a plurality of ball bearings.

[0013] According to another aspect, the pair of bearing assemblies includes a plurality of roller bearings.

[0014] According to another aspect, the at least one lubrication hole supplies oil to openings at ends of the plurality of roller bearings.

[0015] According to another aspect, the outer bearing race of at least one of the pair of bearing assemblies includes an oil catcher extending radially inwardly from an end thereof.

[0016] According to another aspect, the oil catcher is integrally formed with the outer bearing race.

[0017] According to another aspect, an oil trap is connected to the outer bearing race.

[0018] According to another aspect, the drive shaft includes a recessed annular groove in the outer surface that aligns with the at least one lubrication hole in the inner races of the pair of bearing assemblies.

[0019] According to another aspect of the principles of the present disclosure, a motor includes a housing having a stator mounted to the housing. A drive shaft is rotatably mounted within the housing via a pair of bearing assemblies, and a rotor is mounted to the drive shaft. The drive shaft includes a longitudinal oil supply passage therein, the drive shaft also including a first radial passage communicating with the longitudinal oil supply passage and extending to a first of the pair of bearing assemblies and a second radial passage communicating with the longitudinal oil supply passage and extending to a second of the pair of bearing assemblies.

[0020] According to another aspect, the pair of bearing assemblies includes a plurality of roller bearings.

[0021] According to another aspect, the first radial passage and the second radial passage supply oil to openings at ends of the plurality of roller bearings.

[0022] According to another aspect, the outer bearing race of at least one of the pair of bearing assemblies includes an oil catcher extending radially inwardly from an end thereof.

[0023] According to another aspect, the oil catcher is integrally formed with the outer bearing race.

[0024] According to another aspect, the oil trap is connected to the outer bearing race.The at least one lubrication hole includes a plurality of lubrication holes.

[0025] The present invention provides the following technical solutions.

[0026] Technical Solution 1. A motor, comprising:

[0027] case;

[0028] a stator mounted to the housing;

[0029] a drive shaft rotatably mounted within the housing by a pair of bearing assemblies, each of the pair of bearing assemblies including an inner bearing race and an outer bearing race;

[0030] a rotor mounted to the drive shaft; and

[0031] wherein the drive shaft includes a longitudinal oil supply passage therein, the drive shaft includes a first radial passage communicating with the longitudinal oil supply passage and extending to the inner race of the first of the pair of bearing assemblies and a second radial passage communicating with the longitudinal oil supply passage and extending to the inner race of the second of the pair of bearing assemblies, the inner races of the pair of bearing assemblies each including at least one lubrication hole.

[0032] Technical Solution 2. A motor according to Technical Solution 1, wherein at least one of the pair of bearing assemblies includes four contact points.

[0033] Technical Solution 3. A motor according to Technical Solution 2, wherein the at least one lubrication hole is arranged between a pair of contact points of the inner race.

[0034] Technical Solution 4. A motor according to Technical Solution 1, wherein the pair of bearing assemblies include angular contact points.

[0035] Technical Solution 5. A motor according to Technical Solution 4, wherein the at least one lubrication hole is spaced apart from a contact point of the inner race.

[0036] Technical Solution 6. The motor according to Technical Solution 1, wherein the at least one lubrication hole includes a plurality of lubrication holes.

[0037] Technical Solution 7. A motor according to Technical Solution 1, wherein the pair of bearing assemblies includes a plurality of ball bearings.

[0038] Technical Solution 8. A motor according to Technical Solution 1, wherein the pair of bearing assemblies includes a plurality of roller bearings.

[0039] Technical Solution 9. The motor according to Technical Solution 8, wherein the at least one lubrication hole supplies oil to openings at ends of the plurality of roller bearings.

[0040] Technical Solution 10. A motor according to Technical Solution 1, wherein the outer bearing race of at least one of the pair of bearing assemblies includes an oil catcher extending radially inward from an end thereof.

[0041] Technical Solution 11. A motor according to Technical Solution 10, wherein the oil collector is formed integrally with the outer bearing race.

[0042] Technical Solution 12. A motor according to Technical Solution 10, wherein the oil collector is connected to the outer bearing race.

[0043] Technical Solution 13. A motor according to Technical Solution 1, wherein the drive shaft includes a recessed annular groove in the outer surface, and the annular groove is aligned with the at least one lubrication hole in the inner race of the pair of bearing assemblies.

[0044] Technical solution 14. A motor, comprising:

[0045] case;

[0046] a stator mounted to the housing;

[0047] a drive shaft rotatably mounted in the housing via a pair of bearing assemblies;

[0048] a rotor mounted to the drive shaft; and

[0049] wherein the drive shaft includes a longitudinal oil supply passage therein, the drive shaft including a first radial passage connected to the longitudinal oil supply passage and extending to the first of the pair of bearing assemblies and a second radial passage connected to the longitudinal oil supply passage and extending to the second of the pair of bearing assemblies.

[0050] Technical Solution 15. A motor according to Technical Solution 14, wherein the pair of bearing assemblies includes a plurality of roller bearings.

[0051] Technical Solution 16. The motor according to Technical Solution 15, wherein the first radial channel and the second radial channel supply oil to openings at the ends of the plurality of roller bearings.

[0052] Technical Solution 17. A motor according to Technical Solution 14, wherein the outer bearing race of at least one of the pair of bearing assemblies includes an oil catcher extending radially inward from an end thereof.

[0053] Technical Solution 18. A motor according to Technical Solution 17, wherein the oil collector is formed integrally with the outer bearing race.

[0054] Technical Solution 19. A motor according to Technical Solution 17, wherein the oil collector is connected to the outer bearing race.

[0055] Technical Solution 20. A motor according to Technical Solution 14, wherein the at least one lubrication hole comprises a plurality of lubrication holes. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] The present disclosure will be more fully understood from the detailed description and accompanying drawings, in which:

[0057] Figure 1 is a schematic diagram of a motor according to the principles of the present disclosure;

[0058] Figure 2 is a partial cross-sectional view of a drive shaft and bearing assembly according to the principles of the present disclosure;

[0059] Figure 3 is a schematic diagram of a bearing assembly;

[0060] Figure 4 is a cross-sectional view of a four-point contact ball bearing according to the principles of the present disclosure;

[0061] Figure 5 is a cross-sectional view of an angular contact ball bearing according to the principles of the present disclosure; and

[0062] Figure 6 is a partial cross-sectional view of a roller bearing assembly according to the principles of the present disclosure.

[0063] In the drawings, reference numerals may be repeated to identify similar and / or identical elements. DETAILED DESCRIPTION

[0064] Reference Figure 1 , the electric motor 10 is shown to include a housing 12, wherein a stator 14 is fixed to the housing 12. A rotor 16 is rotatably supported within the housing 12 by a drive shaft 18. Figure 2 , the drive shaft 18 is supported at opposite ends by a pair of bearing assemblies 20, 22. The drive shaft 18 includes a longitudinal oil supply passage 24 therein connected to an oil supply source 26. The drive shaft 18 also includes a first radial passage 28 communicating with the longitudinal oil supply passage 24 and extending to a first of the pair of bearing assemblies 20 and a second radial passage 30 communicating with the longitudinal oil supply passage 24 and extending to a second of the pair of bearing assemblies 22.

[0065] Reference Figures 2 to 4, a pair of bearing assemblies 20, 22 includes an inner race 32, an outer race 34, and a plurality of balls 38 supported between the inner race 32 and the outer race 34 by a cage 38. The inner races 32 of the pair of bearing assemblies 20, 22 each include one or more lubrication holes 40, which are in communication with the first radial passage 28 and the second radial passage 30. When multiple lubrication holes 40 are used, they can be spaced circumferentially around the inner race and are preferably located in a non-loaded area 42 of the inner race. In particular, as Figure 4 As shown in , the bearing assemblies 20, 22 may be four-contact bearings in which the balls 38 contact the inner race 32 and the outer race 34 at four contact points 44a-44d such that two of the contact points with the inner race 32 are spaced from the lubrication holes 40. Figure 2 The outer surface of the drive shaft may include a recessed annular groove 46 that communicates with the first and second radial passages 28 , 30 and with the lubrication holes 40 in the inner races 32 of the pair of bearing assemblies 20 , 22 .

[0066] Alternatively, Figure 5 As shown in , the bearing assembly can be an angular contact bearing, wherein the balls 38 of the bearing assemblies 120, 122 contact the inner race 132 and the outer race 134 along the angular contact line 136. Therefore, the lubrication holes 140 of the bearing assemblies 120, 122 are not aligned with the loading area of ​​the angular contact bearings 120, 122.

[0067] According to yet another alternative, Figure 6 As shown in , the bearing assemblies 220, 222 may include roller bearings 238. The inner race 232 of the bearing assemblies 220, 222 includes a lubrication hole 240 that is laterally spaced from the roller bearings 238. In addition, the bearing assemblies 220, 222 may include an outer race 234 having an oil catcher structure 242 that may block the oil and direct the oil back toward the roller bearings 238. The oil catcher structure 242 may be formed integrally with the outer race 234, or formed separately and connected to the outer race 234. It should be understood that the inner race may be formed separately or integrally with the drive shaft 18.

[0068] The previous description is merely illustrative in nature and is in no way intended to limit the present disclosure, its application or use. The broad teachings of the present disclosure can be implemented in many forms. Therefore, although the present disclosure includes specific examples, the true scope of the present disclosure should not be so limited, because after studying the drawings, the specification and the appended claims, other modifications will become apparent. It should be understood that one or more steps in the method can be performed in different orders (or simultaneously) without changing the principles of the present disclosure. In addition, although each embodiment is described above as having certain features, any one or more of those features described with respect to any embodiment of the present disclosure can be implemented in any other embodiment and / or combined with the features of any other embodiment, even if the combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and the arrangement of one or more embodiments to each other is still within the scope of the present disclosure.

[0069] Spatial and functional relationships between elements (e.g., between modules, circuit elements, semiconductor layers, etc.) are described using various terms, including "connected," "engaged," "coupled," "adjacent," "immediately next to," "on top of," "above," "below," and "disposed on." Unless explicitly described as "directly," when describing a relationship between a first element and a second element in the above disclosure, the relationship may be a direct relationship in which no other intermediate elements exist between the first element and the second element, but may also be an indirect relationship in which one or more intermediate elements (spatially or functionally) exist between the first element and the second element. As used herein, the phrase "at least one of A, B, and C" should be interpreted as representing a logical (A or B or C) using a non-exclusive logical "or," and should not be interpreted as representing "at least one of A, at least one of B, and at least one of C."

Claims

1. A motor, comprising: case; a stator mounted to the housing; a drive shaft rotatably mounted within the housing by a pair of bearing assemblies, each of the pair of bearing assemblies including an inner bearing race and an outer bearing race; a rotor mounted to the drive shaft; and wherein the drive shaft includes a longitudinal oil supply passage therein, the drive shaft includes a first radial passage communicating with the longitudinal oil supply passage and extending to the inner race of the first of the pair of bearing assemblies and a second radial passage communicating with the longitudinal oil supply passage and extending to the inner race of the second of the pair of bearing assemblies, the inner races of the pair of bearing assemblies each including at least one lubrication hole.

2. The motor according to claim 1, wherein: At least one of the pair of bearing assemblies includes four contact points.

3. The motor according to claim 2, wherein: The at least one lubrication hole is disposed between a pair of contact points of the inner race.

4. The motor according to claim 1, wherein: The pair of bearing assemblies include angular contact points.

5. The motor according to claim 4, wherein: The at least one lubrication hole is spaced apart from a contact point of the inner race.

6. The motor according to claim 1, wherein: The at least one lubrication hole includes a plurality of lubrication holes.

7. The motor according to claim 1, wherein: The pair of bearing assemblies includes a plurality of ball bearings.

8. The motor according to claim 1, wherein: The pair of bearing assemblies includes a plurality of roller bearings.

9. The motor according to claim 8, wherein: The at least one lubrication hole supplies oil to openings at ends of the plurality of roller bearings.

10. A motor comprising: case; a stator mounted to the housing; a drive shaft rotatably mounted in the housing via a pair of bearing assemblies; a rotor mounted to the drive shaft; and wherein the drive shaft includes a longitudinal oil supply passage therein, the drive shaft including a first radial passage connected to the longitudinal oil supply passage and extending to the first of the pair of bearing assemblies and a second radial passage connected to the longitudinal oil supply passage and extending to the second of the pair of bearing assemblies.

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