Rolling bearing

Abstract

A roller bearing comprises an outer race, an inner race, a plurality of rolling elements placed between the outer race and the inner race, and an electroconductive annular member attached to an axial-directional end part of the outer race, the annular member sectioning a bearing interior where the rolling elements are present and a bearing exterior that is on the outer side of the bearing interior in the axial direction, wherein the annular member has an electroconductive elastic lip part that comes into contact with the inner race, and the annular member is provided with an oil flow path passing through the bearing interior and the bearing exterior.

Description

Technical Field

[0001] The present disclosure relates to rolling bearings.

Background Art

[0002] Patent Document 1 discloses a rolling bearing having an anti-electric corrosion function as a bearing for supporting a rotating shaft of a motor. This rolling bearing includes an outer ring, an inner ring, a plurality of balls disposed between the outer ring and the inner ring, and a sealing plate that closes the space between the outer ring and the inner ring from both axial sides. The sealing plate has a holder fixed to the outer ring and a sliding contact member held by the holder and slidably contacting the outer peripheral surface of the inner ring. The sliding contact member is formed of a fabric containing conductive fibers.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the inner ring of a rolling bearing, for example, is charged due to electricity generated by a motor and the oil film between the balls and the raceway is destroyed, an electric current may flow through the balls to the outer ring. Then, electric corrosion may occur on the raceway surface. According to the rolling bearing disclosed in Patent Document 1, the electricity charged on the inner ring can be passed through the sealing plate to the outer ring, and it becomes possible to prevent electric corrosion on the raceway surface.

[0005] However, even in such a rolling bearing, there are cases where oil is supplied to lubricate the inside of the bearing where the balls are present, or cases where the oil around the rolling bearing is circulated through the rolling bearing. In such cases, in the rolling bearing disclosed in Patent Document 1, since the sealing plate closes the inside of the bearing from both axial sides, it cannot be adopted.

Means for Solving the Problems

[0006] The rolling bearing of the present disclosure includes an outer ring, an inner ring, a plurality of rolling elements disposed between the outer ring and the inner ring, and an annular member attached to an axial end of the outer ring and having conductivity, and the annular member partitions the inside of the bearing where the rolling elements are present and the outside of the bearing that is outside in the axial direction of the inside of the bearing. The rolling bearing is such that the annular member has an elastic lip portion that has conductivity and contacts the inner ring, and an oil flow path that penetrates the inside and the outside of the bearing is provided in the annular member.

Advantages of the Invention

[0007] According to the rolling bearing of the present disclosure, it is possible to prevent electrolytic corrosion of the raceway surface on which the rolling elements roll, and moreover, a rolling bearing that can also cope with the case of using oil can be obtained.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0009] <Summary of Embodiments of the Invention of the Present Disclosure> Hereinafter, the summary of the embodiments of the invention of the present disclosure will be listed and described.

[0010] (1) The rolling bearing of the present disclosure includes an outer ring, an inner ring, a plurality of rolling elements disposed between the outer ring and the inner ring, and an annular member attached to an axial end of the outer ring and having conductivity. The annular member partitions the inside of the bearing where the rolling elements are present and the outside of the bearing that is axially outside the inside of the bearing. The annular member has an elastic lip portion that has conductivity and contacts the inner ring, and an oil flow path that penetrates the inside and the outside of the bearing is provided in the annular member.

[0011] According to the rolling bearing, electricity charged in one of the raceways of the outer ring and the inner ring can flow to the other raceway through the annular member having conductivity, and it is possible to prevent electrical erosion of the raceway surface where the rolling elements roll. Moreover, when the rolling bearing is used in a device having a configuration in which oil circulates through the rolling bearing, the oil flow path makes it possible to secure a path through which the oil flows. When the oil around the rolling bearing is used for lubrication of the rolling bearing, the oil can pass through the oil flow path. Further, the oil does not stay inside the bearing, and it is possible to suppress an increase in stirring resistance. Thus, a rolling bearing that can cope even when using oil can be obtained.

[0012] (2) Preferably, the oil flow path is constituted by a hole penetrating the annular member. In this case, even if the oil flow path is formed by the hole, it is easy to ensure the rigidity of the annular member.

[0013] (3) Alternatively, preferably, the oil flow path is constituted by a notch provided in an inner peripheral edge region of the annular member including the elastic lip portion. In this case, the oil flow path is formed by the notch, and the contact range between the elastic lip portion and the inner ring is reduced, making it possible to reduce the sliding resistance.

[0014] (4) In the rolling bearing of (2) above, preferably, the hole is provided radially outside the pitch circle of the plurality of rolling elements. When the rolling bearing rotates, due to the influence of centrifugal force, oil tends to gather radially outward. By providing the hole closer to the outside in the radial direction of the annular member, the oil can easily pass through the hole.

[0015] (5) In the rolling bearing of (3) above, preferably, a circumferential groove is formed at an axial end of the inner ring, the elastic lip portion is provided in the circumferential groove, and the notch is provided in a portion of the elastic lip portion within the range of the circumferential groove. In this case, a rolling bearing can be obtained in which it is easy to control the amount of oil passing through the notch.

[0016] (6) Preferably, the annular member is provided only on one side in the axial direction, and the annular space between the outer ring and the inner ring is open on the other side in the axial direction. In this case, it becomes possible to supply oil to the inside of the bearing where the rolling elements are provided in the annular space, and also, the function of preventing the supplied oil from becoming excessive and increasing the stirring resistance of the rolling bearing is enhanced.

[0017] <Details of Embodiments of the Invention of the Present Disclosure> Hereinafter, embodiments of the invention of the present disclosure will be described. FIG. 1 is a cross-sectional view showing an example of the rolling bearing of the present disclosure. The rolling bearing 10 shown in FIG. 1 supports the rotating shaft S of a motor mounted on an electric vehicle or a hybrid vehicle. In FIG. 1, the rotating shaft S is indicated by a virtual line (two-dot chain line).

[0018] The rolling bearing 10 includes one outer ring 11, one inner ring 12, a plurality of rolling elements, and one annular member 15. In the present embodiment, the rolling element is a ball 13, and the rolling bearing 10 is a deep groove ball bearing. The outer ring 11 is attached to the housing H of the motor, and the inner ring 12 is externally fitted and fixed to the rotating shaft S. In FIG. 1, the housing H is indicated by a virtual line (two-dot chain line). In the present embodiment, the outer ring 11 becomes the fixed ring, and the inner ring 12 becomes the rotating ring.

[0019] The direction of the rolling bearing 10 of the present disclosure will be described. The outer ring 11 and the inner ring 12 are arranged concentrically, and their center lines are defined as the center line C of the rolling bearing 10. The direction along the center line C and the direction parallel to the center line C are defined as the "axial direction". The direction orthogonal to the center line C is defined as the "radial direction". The direction along a circle centered on the center line C is defined as the "circumferential direction".

[0020] If the left side of FIG. 1 is defined as one axial side (the first axial side) and the right side of FIG. 1 is defined as the other axial side (the second axial side), the annular member 15 is provided only on one axial side of the rolling bearing 10. The annular member 15 is not provided on the other axial side of the rolling bearing 10. The bearing interior K1, which is an annular space J between the outer ring 11 and the inner ring 12 and where the balls 13 are present, is open to the other axial side. In the present embodiment, oil passes through the annular space J of the rolling bearing 10. The direction in which the oil flows may be the direction from one axial side to the other axial side, or the opposite direction.

[0021] An outer ring raceway 21 on which the balls 13 roll is formed on the inner circumferential surface of the outer ring 11. Shoulders 22 are formed on both axial sides of the outer ring raceway 21. A recess 23 is provided on one axial side of the outer ring 11. The recess 23 has a groove shape that is continuous in the circumferential direction, and the annular member 15 is attached to the recess 23. A recess 23 is also formed on the other axial side of the outer ring 11, but the recess 23 may be omitted.

[0022] An inner ring raceway 31 on which the balls 13 roll is formed on the outer circumferential surface of the inner ring 12. Shoulders 32 are formed on both axial sides of the inner ring raceway 31. A circumferential groove 33 is formed at the end on one axial side of the inner ring 12. An elastic lip portion 45, which is a part of the annular member 15, contacts the circumferential groove 33. A circumferential groove 33 is also formed on the other axial side of the inner ring 12, but the circumferential groove 33 may be omitted.

[0023] The balls 13 are arranged between the outer ring 11 and the inner ring 12 and rollingly contact the outer ring raceway 21 and the inner ring raceway 31. The plurality of balls 13 are held at intervals in the circumferential direction by an annular cage 14.

[0024] The cage 14 has an annular body 16 provided on the other axial side of the balls 13 and a plurality of studs 17 extending axially from the annular body 16. The space between two adjacent studs 17, 17 on the one axial side of the annular body 16 in the circumferential direction is a pocket 18 in which the balls 13 are accommodated. The pocket 18 is open on the one axial side.

[0025] Current generated by a motor outside the figure may flow through the rolling bearing 10. The annular member 15 is a member for constituting a path of the current flowing through the rolling bearing 10. That is, the annular member 15 is included in a part of the path of the current flowing through the rolling bearing 10. Therefore, the annular member 15 has conductivity as a whole. The current generated by the motor flows through the rolling bearing 10 through the annular member 15, not through the balls 13.

[0026] An oil film is formed between the balls 13 and the inner ring raceway 31 and the outer ring raceway 21. The oil film functions as an insulating film, but when the oil film is partially broken, electricity may flow between the balls 13 and the inner ring raceway 31 (outer ring raceway 21). However, the annular member 15 prevents the inner ring 12 (or the outer ring 11) from being charged, and even if the oil film is partially broken, it is possible to prevent electricity from flowing between the balls 13 and the inner ring raceway 31 (outer ring raceway 21) in advance. As a result, it is possible to prevent the electrical erosion of the outer ring raceway 21 and the inner ring raceway 31 caused by current flowing through the rolling bearing 10 through the balls 13.

[0027] 〔Regarding the annular member 15〕 The annular member 15 is attached to the axial end of the outer ring 11. The outer end 49 in the radial direction of the annular member 15 fits into the recess 23 of the outer ring 11, thereby fixing the annular member 15 to the outer ring 11. The annular member 15 is annular. The annular member 15 partitions the bearing inner part K1 where the balls 13 are present and the bearing outer part K2 that is outside in the axial direction of the bearing inner part K1. Since the annular member 15 closes the bearing inner part K1 from one axial side, except for a part (oil flow path described later), it can also function as a seal member that suppresses the entry of foreign matters such as wear powder generated in the bearing outer part K2 on one axial side.

[0028] Figure 2 is a cross-sectional view showing the annular member 15 and its surroundings. The annular member 15 has a metal core material (metal ring) 41 and an elastic member 42 made of conductive rubber. The core material 41 is annular and has a bent portion 43 on the inner side in the radial direction. The elastic member 42 covers the core material 41. The elastic member 42 is composed of synthetic rubber, and conductive carbon black or metal powder is blended in the synthetic rubber. Thereby, the elastic member 42 has conductivity. The core material 41 is made of, for example, stainless steel.

[0029] The elastic member 42 has a main body portion 44 that covers the core material 41 and an elastic lip portion 45 that extends inward in the radial direction from the main body portion 44. Since the elastic lip portion 45 is a part of the elastic member 42, it has conductivity. The elastic lip portion 45 contacts the inner ring 12. In the form shown in Figure 2, the elastic lip portion 45 contacts the wall surface 33a facing the axial direction of the circumferential groove 33 formed in the inner ring 12.

[0030] The core material 41 has an annular plate portion 46 and an inclined portion 47 that extends from the inner end 46a in the radial direction of the plate portion 46. The inclined portion 47 is provided so as to extend toward the bearing inner part K1 as it goes inward in the radial direction from the end portion 46a. The elastic member 42 has a covering portion 48 that covers the inclined portion 47. The covering portion 48 may have a lip portion that contacts the shoulder 32 of the inner ring 12, but in the form shown in Figure 2, a gap e is formed between the covering portion 48 and the shoulder 32 of the inner ring 12. The elastic lip portion 45 extends inward in the radial direction from the covering portion 48.

[0031] An adhesive is provided as a film on the surface of the core material 41, and the elastic member 42 covers the core material 41 via the adhesive. The electrical resistance value of the core material 41 including the film (adhesive) is smaller than the electrical resistance value of the elastic member 42. Thereby, the core material 41 is also actively utilized as a conductive member. The volume resistivity of the elastic member 42 is preferably 100 Ω·cm or less, more preferably 20 Ω·cm or less.

[0032] 〔Oil flow path (Part 1)〕 FIG. 3 is a view of the rolling bearing 10 shown in FIGS. 1 and 2 as seen from the axial direction. A plurality of holes 51 penetrating the bearing interior K1 and the bearing exterior K2 are formed in the annular member 15 as oil flow paths. Oil can pass through the holes 51. The holes 51 penetrate the core material 41 and the elastic member 42 in the axial direction. A plurality of holes 51 are provided at intervals in the circumferential direction. In the form shown in FIG. 3, a plurality (four) of holes 51 are provided at equal intervals in the circumferential direction. The holes 51 are circular holes.

[0033] A virtual circle passing through the centers P of the plurality of balls 13 (see FIG. 1) is defined as a pitch circle M (see FIG. 3). The center Q of the hole 51 is provided outside the pitch circle M in the radial direction. In the present embodiment, the four holes 51 are arranged along a single virtual circle N centered on the center line C of the rolling bearing 10. The virtual circle N has a larger radius than the pitch circle M. The arrangement of the holes 51 may be other than the form shown in the drawing.

[0034] 〔Oil flow path (Part 2)〕 A modified example of the oil flow path of the annular member 15 will be described. FIG. 4 is a cross-sectional view of the rolling bearing 10 for explaining a modified example of the annular member 15. FIG. 5 is an explanatory view of the annular member 15 of the rolling bearing 10 shown in FIG. 4 as viewed from the axial direction. In the form shown in FIGS. 4 and 5, the oil flow path is constituted by a notch 52 formed in the annular member 15. The notch 52 is provided in the inner peripheral edge region V of the annular member 15 including the elastic lip portion 45. The elastic lip portion 45 is provided along the circumferential direction, and the notch 52 is partially provided in the elastic lip portion 45.

[0035] The notch 52 has a shape that penetrates the elastic lip portion 45 in the axial direction. A plurality of notches 52 are provided at intervals in the circumferential direction. In the form shown in FIG. 5, four notches 52 are provided at equal intervals in the circumferential direction.

[0036] FIG. 6 is an enlarged cross-sectional view showing the notch 52 constituting the oil flow path and its surroundings. The radially formed range of the notch 52 in the elastic lip portion 45 is the range of the circumferential groove 33 provided in the inner ring 12. That is, the radially outer end 52e of the notch 52 coincides with a virtual cylindrical surface I passing through the shoulder 32 of the inner ring 12, or is located radially inward of the virtual cylindrical surface I. Note that the radially formed range of the notch 52 may be otherwise. Although not shown, for example, the radially outer end 52e of the notch 52 may be located radially outward of the virtual cylindrical surface I. In this case, the notch 52 may be formed in a part (inner peripheral end portion) of the core material 41 in addition to the elastic lip portion 45.

[0037] Regarding the rolling bearing 10 of each of the above forms As described above, the rolling bearing 10 in each of the above-described embodiments (see FIGS. 1 and 4) includes an annular member 15 attached to an axial end portion of the outer ring 11. The annular member 15 has conductivity as a whole. The annular member 15 partitions the inside K1 of the bearing from the outside K2 of the bearing. The annular member 15 has an elastic lip portion 45 that has conductivity and contacts the inner ring 12. An oil flow path that penetrates the inside K1 of the bearing and the outside K2 of the bearing is provided in the annular member 15. In the embodiment shown in FIG. 1, the oil flow path is a hole 51, and in the embodiment shown in FIG. 4, the oil flow path is a notch 52.

[0038] According to the rolling bearing 10, electricity charged in the inner ring 12 can flow to the outer ring 11 through the conductive annular member 15, and it is possible to prevent electrolytic corrosion of the raceway surfaces (outer ring raceway 21, inner ring raceway 31) on which the balls 13 roll. Moreover, when oil circulates inside the device through the rolling bearing 10, the oil flow path makes it possible to secure a path through which the oil flows. When the oil around the rolling bearing 10 is used for lubricating the rolling bearing 10, the oil can pass through the oil flow path. For this reason, the oil does not stay in the inside K1 of the bearing, and it is possible to suppress an increase in stirring resistance during bearing rotation. Thus, a rolling bearing 10 that can also handle such a case where oil is used can be obtained.

[0039] In the rolling bearing 10 shown in each of FIGS. 1 and 4, the annular member 15 is provided only on one side in the axial direction, and the annular space J between the outer ring 11 and the inner ring 12 is open on the other side in the axial direction. For this reason, it is possible to supply oil to the inside K1 of the bearing in which the balls 13 are provided from the other side in the axial direction. If the oil flow path (hole 51, notch 52) is made to function as an oil discharge flow path, the supplied oil does not become excessive in the inside K1 of the bearing, and it is possible to prevent the stirring resistance of the rolling bearing 10 from increasing.

[0040] In the rolling bearing 10 shown in FIGS. 1 and 4, for example, when oil circulates inside a device such as a motor, and the flow direction of the oil is from one axial side to the other axial side, the oil enters the bearing interior K1 through the oil flow path (hole 51, notch 52). Therefore, in particular, it is possible to prevent the oil in the bearing interior K1 from becoming excessive and suppress an increase in stirring resistance during bearing rotation.

[0041] In the form shown in FIG. 1, the oil flow path is constituted by a hole 51 penetrating the annular member 15. In this case, even if the oil flow path is formed by the hole 51 which is a missing part, it is easy to ensure the rigidity of the annular member 15. When the rolling bearing 10 rotates, due to the influence of centrifugal force, the oil tends to gather radially outward. Therefore, as shown in FIG. 3, the hole 51 (center Q of the hole 51) is provided radially outside the pitch circle M of the plurality of balls 13. By providing the hole 51 closer to the outer side in the radial direction of the annular member 15, the oil can easily pass through the hole 51.

[0042] In the form shown in FIG. 4, the oil flow path is constituted by a notch 52 provided in the inner peripheral edge region V of the annular member 15 including the elastic lip portion 45. In this case, while the oil flow path is formed by the notch 52, the contact range between the elastic lip portion 45 and the inner ring 12 is reduced, and it is possible to reduce the sliding resistance.

[0043] A circumferential groove 33 is formed at the axial end of the inner ring 12, and the elastic lip portion 45 is provided in the circumferential groove 33. As shown in FIG. 6, the notch 52 is provided in the portion of the elastic lip portion 45 within the range of the circumferential groove 33. In this case, a rolling bearing 10 in which it is easy to control the amount of oil passing through the notch 52 can be obtained. In particular, as shown in FIG. 6, the annular member 15 has a covering portion 48 that faces the shoulder 32 of the inner ring 12 with a gap e on its inner peripheral side. The gap e and the notch 52 limit the amount of oil passing through.

[0044] 〔Others〕 In the above embodiment, the case where the outer ring 11 is a fixed ring and the inner ring 12 is a rotating ring has been described. On the contrary, the outer ring 11 may be a rotating ring and the inner ring 12 may be a fixed ring. Even in this case, the annular member 15 is attached to the axial end portion of the outer ring 11, and the configuration of the annular member 15 is the same as each form shown in FIG. 1 or FIG. 4.

[0045] The annular member 15 may be provided at both axial end portions of the rolling bearing 10. In the above embodiment, the case where the rolling bearing 10 is a deep groove ball bearing has been described, but the rolling bearing 10 may be an angular ball bearing or a roller bearing in which the rolling elements are rollers.

[0046] The above embodiments are illustrative in all respects and not restrictive. The scope of the rights of the present invention is indicated by the claims rather than the above embodiments, and includes all modifications within the scope equivalent to the configurations described in the claims.

Explanation of Reference Numerals

[0047] 10 Rolling bearing 11 Outer ring 12 Inner ring 13 Ball (rolling element) 15 Annular member 33 Circumferential groove 45 Elastic lip portion 51 Hole (oil flow path) 52 Notch (oil flow path) K1 Inside the bearing K2 Outside the bearing M Pitch circle V Inner peripheral region

Claims

1. An outer ring, an inner ring, a plurality of rolling elements disposed between the outer ring and the inner ring, and an annular member having conductivity and attached to an axial end portion of the outer ring, wherein the annular member partitions a bearing interior where the rolling elements are present and a bearing exterior that is outside in the axial direction of the bearing interior, and is a rolling bearing, The annular member has an elastic lip portion that has conductivity and contacts the inner ring, An oil flow path that penetrates the bearing interior and the bearing exterior is provided in the annular member, The oil flow path is constituted by a notch provided in an inner peripheral edge region of the annular member including the elastic lip portion, A circumferential groove is formed in an axial end portion of the inner ring, The elastic lip portion is provided in the circumferential groove, The notch is provided in a portion of the elastic lip portion within the range of the circumferential groove, and is a rolling bearing.

2. The rolling bearing according to claim 1, wherein the annular member is provided only on one side in the axial direction, and an annular space between the outer ring and the inner ring is open on the other side in the axial direction.

Images