One-way clutch

Abstract

A one-way clutch, comprising an input gear (10), an output shaft (20), bearing needles (30), an inner race (40), an outer race (50), and rolling elements (60), wherein a radial clearance for accommodating the bearing needles is formed between the input gear and the output shaft; the inner race is located radially and axially between the input gear and the outer race and is fixed to the input gear by means of a radial inner side portion of the inner race; the rolling elements are mounted in a cavity formed radially between the outer race and the inner race; the input gear comprises a first end face (14) axially facing the outer race, the inner race comprises a second end face (43) axially facing the outer race, and the second end face is located on the radial outer side of the first end face; the outer race comprises a third end face (53) axially facing the first end face and the second end face; and at least one first oil guide groove (44) is formed in at least one of the second end face and the third end face, and lubricant from the radial clearance can enter the cavity through the first oil guide groove.

Description

One-way clutch Technical Field

[0001] This invention relates to the field of transmission technology. Specifically, this invention relates to a one-way clutch. Background Technology

[0002] In some transmission systems, different one-way clutches (OWCs) are required, such as the disconnect device in a hybrid system acting as an electric vehicle axle. In some existing technologies, the freewheel clutch is integrated into the gear assembly or shaft assembly. In these applications, the helical teeth of the gears generate not only radial but also axial forces when running under no-load conditions. These forces are absorbed by the friction surfaces of the rolling elements of the one-way clutch, potentially causing wear on the rolling elements. The friction surfaces of the rolling elements must be properly lubricated to minimize friction and wear. A common solution in existing technologies is to create oil grooves on the gears or shaft shoulders. However, these methods not only provide unsatisfactory lubrication but also have high production costs. Summary of the Invention

[0003] Therefore, the technical problem that this invention needs to solve is to provide an improved one-way clutch.

[0004] The aforementioned technical problem is solved by a one-way clutch according to the present invention. The one-way clutch includes an input gear, an output shaft, bearing needle rollers, an inner ring, an outer ring, and rolling elements. The input gear is rotatably supported radially outward of the output shaft by the bearing needle rollers, and a radial clearance is formed between the input gear and the output shaft to accommodate the bearing needle rollers. The outer ring is torsionally mounted radially outward of the output shaft. The inner ring is located radially and axially between the input gear and the outer ring and is fixed to the input gear via its radially inner portion. The rolling elements are mounted in a cavity formed radially between the outer ring and the inner ring and are capable of unidirectionally transmitting torque between the outer ring and the inner ring. The input gear includes a first end face axially facing the outer ring. The inner ring includes a second end face axially facing the outer ring, the second end face being radially outward of the first end face. The outer ring includes a third end face axially facing the first and second end faces. At least one of the second and third end faces has at least one first oil groove formed, through which lubricant from the radial clearance can enter the cavity. The first oil groove can effectively guide the lubricant from the bearing needle rollers into the one-way clutch, thereby lubricating the rolling elements.

[0005] According to a preferred embodiment of the present invention, the second end face may be formed with at least one first oil groove, each of the first oil grooves extending from the radial inner periphery to the radial outer periphery of the second end face. This effectively guides the flow of lubricant across the second end face.

[0006] According to another preferred embodiment of the present invention, the first end face may be formed with one or more second oil grooves, each second oil groove extending from the radial inner periphery to the radial outer periphery of the first end face. The second oil grooves can effectively guide the flow of lubricant across the first end face.

[0007] According to another preferred embodiment of the present invention, the third end face may be formed with at least one first oil groove, each first oil groove on the third end face extending radially outward from the radially inner periphery of the third end face to the radially outer periphery of the second end face. The first oil groove on the third end face can guide the lubricant flow across the first and second end faces, thereby entering the cavity accommodating the rolling element.

[0008] According to another preferred embodiment of the invention, each first oil groove formed on the same end face can extend radially and has a circumferential width that gradually decreases or increases radially, thereby having a trapezoidal shape in a cross-section perpendicular to the axial direction, wherein: the circumferential width of each first oil groove formed on the same end face can gradually decrease radially from the inside to the outside; or the circumferential width of each first oil groove formed on the same end face can gradually increase radially from the inside to the outside. The trapezoidal oil grooves can promote lubricant flow through hydraulic principles.

[0009] According to another preferred embodiment of the invention, each first oil groove formed on the same end face can extend radially and has a constant circumferential width radially, thus having a rectangular shape in a cross-section perpendicular to the axial direction. Such oil grooves are easy to manufacture.

[0010] According to another preferred embodiment of the invention, each first oil groove formed on the same end face may extend obliquely relative to the radial direction. Preferably, each first oil groove formed on the same end face may extend along an arc. The oblique oil grooves can utilize the principle of centrifugal force to promote lubricant flow.

[0011] According to another preferred embodiment of the invention, the output shaft may include a shoulder, which may include an end face facing the bearing needle rollers axially. An outer ring is axially mounted on the end face of the output shaft facing away from the shoulder and in the region adjacent to the shoulder. A communication gap may be formed between the shoulder and the input gear. The communication gap can effectively guide lubricant flow to the first oil groove.

[0012] According to another preferred embodiment of the invention, the output shaft may be formed as a hollow shaft and include at least one oil inlet, each oil inlet communicating from the radial inner surface of the output shaft to the radial clearance. The oil inlet can introduce lubricant from the output shaft cavity into the radial clearance.

[0013] According to another preferred embodiment of the present invention, at least one of the second end face and the third end face may be formed with a plurality of first oil grooves spaced apart circumferentially. This improves the lubrication effect. Attached Figure Description

[0014] The invention is further described below with reference to the accompanying drawings. In the drawings, the same reference numerals represent elements with the same function. Wherein:

[0015] Figure 1 shows a longitudinal sectional view of a one-way clutch according to an exemplary embodiment of the present invention;

[0016] Figure 2 shows a partially enlarged longitudinal sectional view of a one-way clutch according to an exemplary embodiment of the present invention;

[0017] Figures 3a to 3d show perspective views of the inner ring of a one-way clutch according to different embodiments of the present invention; and

[0018] Figure 4 shows a perspective view of the input gear of a one-way clutch according to an exemplary embodiment of the present invention. Detailed Implementation

[0019] The following describes specific embodiments of the one-way clutch according to the present invention with reference to the accompanying drawings. The detailed description and drawings below are provided to illustrate the principles of the invention, and the invention is not limited to the described preferred embodiments; the scope of protection of the invention is defined by the claims.

[0020] According to an embodiment of the present invention, a one-way clutch is provided. This one-way clutch can be used, for example, in the powertrain of a hybrid vehicle, such as being positioned between the engine or drive motor and the transmission.

[0021] Figure 1 shows a longitudinal sectional view of this one-way clutch. As shown in Figure 1, this one-way clutch includes an input gear 10, an output shaft 20, bearing needle rollers 30, an inner ring 40, an outer ring 50, and rolling elements 60.

[0022] The input / output wheel 10 is generally formed as a disc-shaped component, including an outer ring portion 11, an inner ring portion 12, and a connecting portion 13. The outer ring portion 11 and the inner ring portion 12 are formed as a generally cylindrical structure arranged coaxially, with the outer ring portion 11 located radially outside the inner ring portion 12 and radially spaced apart from it. The connecting portion 13 extends generally radially between the axial ends of the outer ring portion 11 and the inner ring portion 12 on the same side, thereby connecting them together. This creates an annular space open towards one axial end between the outer ring portion 11 and the inner ring portion 12 radially. Gear teeth are formed on the radially outer side of the outer ring portion 11 to receive torque, for example, from an engine or drive motor.

[0023] The output shaft 20 is generally formed as a hollow cylinder. The output shaft 20 can be rotatably supported on other components at both ends axially by two bearings 70 and 80, respectively. The output shaft 20 has a gear portion 21 for outputting torque to, for example, a transmission. The gear portion 21 is axially located between the two bearings 70 and 80. The input gear 10 is rotatably supported radially outward of the output shaft 20 by bearing needle rollers 30. The input gear 10 and the bearing needle rollers 30 are axially located between a bearing 70 and the gear portion 21. A radial clearance is formed between the input gear 10 and the output shaft 20, in which the bearing needle rollers 30 are accommodated. The one-way clutch preferably includes a plurality of bearing needle rollers 30 arranged circumferentially at intervals, particularly uniformly. Each bearing needle roller 30 is formed as a generally cylindrical body of the same shape and is capable of rolling about the common central axis of the input gear 10 and the output shaft 20 along their opposing surfaces, thereby allowing them to rotate relative to each other about the common central axis. To constrain the bearing needle rollers 30 in the axial direction, the output shaft 20 may be formed with a shoulder 22. The shoulder 22 has an end face facing the bearing needle rollers 30 in the axial direction, such that each bearing needle roller 30 is constrained in the axial direction between the end face of the shoulder 22 and the bearing 70.

[0024] The outer ring 50 includes two annular sections: a radial section 51 and an axial section 52. Both the radial section 51 and the axial section 52 are axially located on the side of the connecting portion 13 facing away from the bearing 70. The axial section 52 is generally cylindrical and is located radially between the outer ring portion 11 and the inner ring portion 12, extending generally axially. The radial section 51 extends generally radially inward from the end of the axial section 52 facing away from the connecting portion 13 until it abuts against the output shaft 20, thereby torsionally mounting the outer ring 50 to the radially outer side of the output shaft 20. The radial section 51 can be torsionally connected to the output shaft 20, for example, by an interference fit and / or splines, particularly by a fixed connection. The radial section 51 is axially located between the inner ring portion 12 and the gear portion 21, particularly in the region axially mounted on the end face of the output shaft 20 facing away from the shoulder 22 and adjacent to the shoulder 22. The inner ring 12 is loosely fitted between the bearing 70 and the radial section 51 in the axial direction and can abut against the radial section 51 in the axial direction.

[0025] The inner ring 40 also includes two annular segments: a radial segment 41 and an axial segment 42. The axial segment 42 is generally cylindrical and is located radially between the axial segment 52 and the inner ring portion 12, extending generally axially. The axial segment 42 abuts against the inner ring portion 12 and is fixed to the inner ring portion 12, for example, by an interference fit, thereby fixing the inner ring 40 to the input gear 10 via its own radially inner portion. The radial segment 41 extends generally radially outward from the end of the axial segment 42 facing away from the connecting portion 13, but does not extend to contact the axial segment 52 of the outer ring 50. As shown in FIG2, this arrangement ensures that the inner ring 40 is located both radially and axially between the input gear 10 and the outer ring 50.

[0026] A cavity is formed radially between the outer ring 50 and the inner ring 40. As shown in FIG2, the inner wall of this cavity is provided by the axial section 42 of the inner ring 40, the outer wall is provided by the axial section 52 of the outer ring 50, one axial end wall is provided by the connecting portion 13 of the input gear 10, and the radially inner portion of the other axial end wall is provided by the radial section 41 of the inner ring 40, and the radially outer portion is provided by the radial section 51 of the outer ring 50. Rolling elements 60 are mounted in this cavity. The one-way clutch may include a plurality of rolling elements 60 arranged circumferentially. To maintain the circumferential spacing of these rolling elements 60, a cage may also be provided in the cavity. The rolling elements 60 may mate with guide surfaces on the inner ring 40 or the outer ring 50, thereby transmitting torque unidirectionally between the outer ring 50 and the inner ring 40.

[0027] As shown in Figure 2, the axial surface of the inner ring portion 12 of the input gear 10 facing the outer ring 50 can be referred to as the first end face 14, and the axial surface of the radial portion 41 of the inner ring 40 facing the outer ring 50 can be referred to as the second end face 43, which is located radially outside the first end face 14. The axial surface of the radial portion 51 of the outer ring 50 facing both the first end face 14 and the second end face 43 can be referred to as the third end face 53. A certain amount of lubricant, such as grease, is usually filled in the radial clearance accommodating the bearing needle rollers 30. This lubricant is mainly used to lubricate the bearing needle rollers 30. The rolling elements 60 also require lubrication. In order to introduce the lubricant in the radial clearance into the cavity accommodating the rolling elements 60, in the one-way clutch according to the invention, at least one of the second end face 43 and the third end face 53 is formed with at least one first oil groove so that the lubricant from the radial clearance can enter the cavity through these first oil grooves. Since the output shaft 20 can be formed as a hollow shaft, at least one oil inlet 23 can also be formed on the output shaft 20. Each oil inlet 23 extends approximately radially from the radially inner surface of the output shaft 20 to the radially outer surface, thereby communicating with the radial clearance. This allows lubricant to be supplied from the cavity of the output shaft 20 to the radial clearance. Since the input gear 10, output shaft 20, inner ring 40, and outer ring 50 are all rotating components, the lubricant can be driven by centrifugal force to flow radially outward along the first oil groove until it enters the cavity accommodating the rolling element 60.

[0028] The first oil guide groove can have various specific implementations. As shown in Figures 3a to 3d, in some preferred embodiments, at least one such first oil guide groove 44 can be formed on the second end face 43 of the inner ring 40. Each first oil guide groove 44 on the second end face 43 extends from the radially inner periphery to the radially outer periphery of the second end face 43, thereby guiding the lubricant to flow from the radially inner side to the radially outer side across the second end face 43 and finally into the cavity accommodating the rolling element 60. The second end face 43 is preferably formed with a plurality of first oil guide grooves 44 spaced circumferentially, these first oil guide grooves 44 are preferably evenly distributed, and preferably have the same shape and size as each other. Possible shapes of the first guide groove 44 will be described below with reference to Figures 3a to 3d.

[0029] As shown in Figures 3a and 3b, each first oil groove 44 formed on the second end face 43 extends generally radially and has a circumferential width that gradually decreases or increases radially. Therefore, when viewed in a cross-section perpendicular to the axial direction, each first oil groove 44 has a generally trapezoidal shape. In the embodiment shown in Figure 3a, the circumferential width of each first oil groove 44 on the second end face 43 may gradually increase radially from the inside to the outside. Alternatively, in the embodiment shown in Figure 3b, the circumferential width of each first oil groove 44 on the second end face 43 may also gradually decrease radially from the inside to the outside.

[0030] In the embodiment shown in FIG3c, each first oil groove 44 formed on the second end face 43 extends generally radially and has a generally constant circumferential width in the radial direction. Therefore, when viewed in a cross-section perpendicular to the axial direction, the first oil groove 44 has a generally rectangular shape.

[0031] In the embodiment shown in FIG3d, each first oil inlet groove 44 formed on the second end face 43 may extend obliquely relative to the radial direction. When a plurality of first oil inlet grooves 44 are formed on the second end face 43, the extending direction of these first oil inlet grooves 44 is preferably obliquely in the same direction relative to the radial direction, that is, obliquely towards the same circumferential side relative to the radial direction. Each such oblique first oil inlet groove 44 may extend along a generally straight line or along an arc.

[0032] In some preferred embodiments, as shown in FIG4, one or more second oil grooves 15 may also be formed on the first end face 14. Similar to the first oil groove 44, each second oil groove 15 extends from the radial inner periphery to the radial outer periphery of the first end face 14. Each second oil groove 15 may extend substantially radially. Preferably, a plurality of second oil grooves 15 may be formed on the first end face 14 at circumferential intervals, and these second oil grooves 15 may preferably be evenly distributed and preferably have the same shape and size as each other. The second oil grooves 15 are particularly advantageous when the first oil groove 44 is formed only on the second end face 43. This is because the first oil groove 44 cannot extend into the radial region of the first end face 14 and therefore cannot directly communicate with the radial clearance. At the same time, the input gear 10 is positioned in a loosely fitted manner in the axial direction and may therefore abut against the third end face 53 in the axial direction, so the lubricant from the radial clearance does not easily pass between the first end face 14 and the third end face 53. When the second oil inlet groove 15 is provided, the lubricant from the radial clearance can flow more easily into the first oil inlet groove 44 through the second oil inlet groove 15.

[0033] As shown in Figure 4, in some other preferred embodiments, at least one such first oil inlet groove may also be formed on the third end face 53. Each first oil inlet groove on the third end face 53 may extend radially outward from the radially inner periphery of the third end face 53 until it crosses the radially outer periphery of the second end face 43. The first oil inlet grooves on the third end face 53 may adopt a similar shape and / or distribution to the first oil inlet grooves 44 on the second end face 43 (as shown in Figures 3a to 3d), which will not be described further here.

[0034] In the one-way clutch according to the present invention, the first oil groove can be provided on both the second end face 43 and the third end face 53, or it can be provided on only one of the second end face 43 and the third end face 53. Generally, it is preferable to provide the first oil groove 44 only on the second end face 43. This is because the radial section 41 where the second end face 43 is located does not need to participate in torque transmission, so the requirement for structural strength is not high, and providing the first oil groove 44 will not significantly affect the structural strength of the second end face 43; while the radial section 51 where the third end face 53 is located needs to participate in torque transmission, so the requirement for structural strength is high. If the first oil groove 44 is provided on the third end face 53, care must be taken to avoid affecting the structural strength of the radial section 51.

[0035] Furthermore, in a further preferred embodiment, to facilitate the flow of lubricant from the radial clearance, a connecting gap G can be formed between the shoulder 22 and the input gear 10. The connecting gap G can be formed as follows: on one hand, an inclined chamfered region is formed at the outer edge of the shoulder 22; on the other hand, an inclined chamfered region is also formed at the inner edge of the first end face 14 of the inner ring portion 12. These two chamfered regions are opposite each other in a direction inclined about the axial direction and spaced apart by a certain distance, thereby forming the connecting gap G. The lubricant in the radial clearance accommodating the bearing needle roller 30 can flow through the connecting gap G to the gap or oil groove between the first end face 14 and the third end face 53, and then to the cavity accommodating the rolling element 60.

[0036] The one-way clutch according to the invention allows lubricant to be drawn from the bearing needle rollers to the rolling elements via an oil priming groove. Since all components are rotating, and there may be relative rotation between the two components on either side of the oil priming groove, centrifugal force can drive the lubricant to flow radially outward and ultimately into the cavity housing the rolling elements. This allows for effective lubrication of the rolling elements. Consequently, wear and heat generation of the rolling elements are reduced, thereby increasing the service life of the one-way clutch.

[0037] While possible embodiments have been described exemplarily in the foregoing description, it should be understood that numerous variations of embodiments exist through combinations of all known and readily conceived technical features and implementation methods. Furthermore, it should be understood that the exemplary embodiments are merely examples and do not in any way limit the scope, application, or construction of the invention. The foregoing description is more intended to provide those skilled in the art with technical guidance for transforming at least one exemplary embodiment, wherein various changes, particularly regarding the function and structure of the components, can be made without departing from the scope of the claims.

[0038] Table 10 Reference Numerals: Input Gear; 11 Outer Ring; 12 Inner Ring; 13 Connecting Part; 14 First End Face; 15 Second Oil Groove; 20 Output Shaft; 21 Gear Part; 22 Shoulder; 23 Oil Hole; 30 Bearing Needle Roller; 40 Inner Ring; 41 Radial Section; 42 Axial Section; 43 Second End Face; 44 First Oil Groove; 50 Outer Ring; 51 Radial Section; 52 Axial Section; 53 Third End Face; 60 Rolling Element; 70 Bearing; 80 Bearing G; Communicating Clearance.

Claims

1. A one-way clutch, comprising an input gear (10), an output shaft (20), bearing needle rollers (30), an inner ring (40), an outer ring (50), and rolling elements (60), wherein the input gear (10) is rotatably supported on the radially outer side of the output shaft (20) by the bearing needle rollers (30), and a radial clearance is formed between the input gear (10) and the output shaft (20) to accommodate the bearing needle rollers (30); the outer ring (50) is torsionally mounted to the radially outer side of the output shaft (20); the inner ring (40) is located radially and axially between the input gear (10) and the outer ring (50) and is fixed to the input gear (10) by the radially inner portion of the inner ring (40); the rolling elements (60) are mounted in a cavity formed radially between the outer ring (50) and the inner ring (40) and are capable of unidirectionally transmitting torque between the outer ring (50) and the inner ring (40), characterized in that, The input gear (10) includes a first end face (14) facing the outer ring (50) axially, the inner ring (40) includes a second end face (43) facing the outer ring (50) axially, the second end face (43) being located radially outside the first end face (14), the outer ring (50) includes a third end face (53) facing the first end face (14) and the second end face (43) axially, at least one of the second end face (43) and the third end face (53) having at least one first oil groove (44) through which lubricant from the radial clearance can enter the cavity.

2. The one-way clutch according to claim 1, characterized in that, The second end face (43) is formed with at least one first oil groove (44), each of the first oil grooves (44) of the second end face (43) extending from the radial inner periphery to the radial outer periphery.

3. The one-way clutch according to claim 2, characterized in that, The first end face (14) is formed with one or more second oil inlet grooves (15), each second oil inlet groove (15) extending from the radial inner periphery to the radial outer periphery of the first end face (14).

4. The one-way clutch according to claim 1, characterized in that, The third end face (53) is formed with at least one first oil inlet groove, each of the first oil inlet grooves of the third end face (53) extending radially outward from the radial inner periphery of the third end face (53) to the radial outer periphery beyond the second end face (43).

5. The one-way clutch according to claim 1, characterized in that, Each first oil inlet groove (44) formed on the same end face extends radially and has a circumferential width that gradually decreases or increases radially, thus having a trapezoidal shape in a cross-section perpendicular to the axial direction, wherein: The circumferential width of each first oil inlet groove (44) formed on the same end face gradually decreases radially from the inside to the outside; or The circumferential width of each first oil inlet groove (44) formed on the same end face gradually increases radially from the inside to the outside.

6. The one-way clutch according to claim 1, characterized in that, Each first oil groove (44) formed on the same end face extends radially and has a constant circumferential width in the radial direction, thus having a rectangular shape in a cross section perpendicular to the axial direction.

7. The one-way clutch according to claim 1, characterized in that, Each first oil groove (44) formed on the same end face extends obliquely in the same direction relative to the radial direction.

8. The one-way clutch according to claim 7, characterized in that, Each first oil groove (44) formed on the same end face extends along an arc.

9. The one-way clutch according to claim 1, wherein the output shaft (20) includes a shoulder (22) having an end face facing the bearing needle roller (30) axially, the outer ring (50) being axially mounted in the region of the output shaft (20) facing away from the shoulder (22) and adjacent to the shoulder (22), forming a communication gap (G) between the shoulder (22) and the input gear (10).

10. The one-way clutch according to claim 1, characterized in that, The output shaft (20) is formed as a hollow shaft and includes at least one oil inlet (23), each oil inlet (23) communicating from the radial inner surface of the output shaft (20) to the radial gap.

11. The one-way clutch according to any one of claims 1 to 10, characterized in that, At least one of the second end face (43) and the third end face (53) is formed with a plurality of first oil inlet grooves (44) distributed circumferentially.

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