Fixed-center constant velocity joint

Abstract

A fixed-center constant velocity joint includes an inner race having inner ball tracks extending between opposite inner race sides and an outer race having outer ball tracks extending between opposite outer race sides. The inner ball tracks have inner ball track radii of curvature extending between the inner race sides. The outer ball tracks have outer ball track radii of curvature extending between the outer race sides. At least one of the inner ball track radii of curvature has a convex curvature and at least one of the inner ball track radii of curvature has a concave curvature, and / or at least one of the inner ball track radii of curvature has a radius origin offset from a center axis of rotation, and / or at least one of the outer ball track radii of curvature has a radius origin offset from the center axis of rotation.

Description

[0001] Cross-reference to related applications

[0002] This disclosure claims the benefit of U.S. Provisional Application Serial No. 63 / 868,680, filed August 22, 2025, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure generally relates to axle assemblies for motor vehicles, and more specifically to constant velocity universal joints for axle assemblies. Background Technology

[0004] Constant velocity joints (CVJs) for automotive axle joint applications have an increasing demand for low mass, small package, high mechanical efficiency, and desired angles. To improve mechanical efficiency, straight helical ball tracks are known to be incorporated; however, this typically leads to an increased package size. To reduce package size, a smaller helix angle can be used; however, this usually results in increased clicking noise. Furthermore, some CVJs offer axial travel movement in addition to angle adjustment, but this is not always necessary depending on the application.

[0005] Therefore, there is a need for a fixed-center constant velocity universal joint that overcomes at least the above-mentioned disadvantages while having low mass, small packaging, high mechanical efficiency, and the desired angle adjustment. Summary of the Invention

[0006] One aspect of this disclosure provides a fixed-center constant velocity universal joint, comprising an inner ring having opposing inner ring sides, wherein a plurality of inner rolling member tracks follow a helical path relative to a rotational center axis. Each inner rolling member track has a radius of curvature extending from one inner ring side to the other inner ring side. An outer ring is disposed around the inner ring such that the inner and outer rings extend about a common rotational center axis. The outer ring has opposing outer ring sides, wherein a plurality of outer rolling member tracks follow a helical path relative to a rotational center axis. Each outer rolling member track has a radius of curvature extending from one outer ring side to the other outer ring side. The outer rolling member tracks and inner rolling member tracks are arranged in pairs to define a plurality of rolling member raceways. At least one rolling member is disposed in each rolling member raceway for rolling reception within the inner and outer rolling member tracks. At least one inner rolling member has a convex (convex) radius of curvature, and the paired outer rolling members have concave (concave) radii of curvature. The fixed-center constant velocity universal joint allows relative angular movement between the inner and outer rings while preventing relative axial movement between them along the axis of rotation.

[0007] According to another aspect of this disclosure, a fixed-center constant velocity universal joint is provided, comprising an inner ring and an outer ring disposed around the inner ring such that the inner and outer rings extend about a common rotational central axis. The inner ring has opposing inner ring sides, wherein a plurality of inner rolling member tracks extend from one inner ring side to another along a helical path relative to the rotational central axis. The outer ring has opposing outer ring sides, wherein a plurality of outer rolling member tracks extend from one outer ring side to another along a helical path relative to the rotational central axis. The outer rolling member tracks are arranged in pairs with the inner rolling member tracks to define a plurality of rolling member raceways extending helically relative to the rotational central axis. At least one rolling member is disposed in each rolling member raceway for rolling reception within the inner and outer rolling member tracks. Each inner rolling member track has an inner rolling member track radius of curvature extending from one inner ring side to another inner ring side. Each outer rolling member track has an outer rolling member track radius of curvature extending from one outer ring side to another outer ring side. At least one inner rolling element track has a radius of curvature that is offset from the axis of rotation, with an origin of radius (center of radius, center of curvature). A fixed-center constant velocity universal joint allows relative angular movement between the inner and outer rings while preventing relative axial movement between them along the axis of rotation.

[0008] These and other aspects, objects, advantages, and features will become apparent to those skilled in the art from the following description taken in conjunction with the accompanying drawings. Attached Figure Description

[0009] The subject matter of this disclosure is specifically pointed out and clearly claimed in the claims at the end of the specification. The foregoing and other features and advantages of this disclosure will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, in which: Figure 1 It is a cross-sectional view constructed according to one aspect of this disclosure, taken approximately along the longitudinal rotation center axis of a fixed-center constant velocity universal joint. Figure 2 yes Figure 1 A partial schematic cross-sectional view of a fixed-center constant velocity universal joint; and Figure 3 yes Figure 1 A partial schematic side sectional view of the outer ring of a fixed-center constant velocity universal joint, showing the unrestricted radius of curvature with the origin of the radius located on the central axis of the outer ring. Detailed Implementation

[0010] This disclosure will now be described with reference to the accompanying drawings, in which specific embodiments will be used, but not limited thereto. Figure 1A fixed-center constant velocity joint, also known as a constant velocity joint (CVJ) 10, constructed according to one aspect of this disclosure is shown. The CVJ 10 includes an inner ring 12 having opposing inner ring sides (also known as inner sides 12a, 12b), wherein a plurality of individual inner rolling member tracks (also known as inner ball tracks 14) extend from one of the inner ring sides 12a to the other of the inner ring sides 12b. The inner ball tracks 14 are circumferentially spaced from each other in an equidistant relationship around the outer periphery of the inner ring 12. The CVJ 10 also includes an outer ring 16, wherein the outer ring 16 is disposed around the inner ring 12 such that the inner ring 12 and the outer ring 16 extend about a common rotational central axis (referred to as central axis 18). The outer ring 16 has opposing outer ring sides, also referred to as outer sides 16a, 16b, wherein a plurality of outer rolling element tracks, also referred to as outer ball tracks 20, extend from one of the outer ring sides (shown as outer ring side 16b) toward the other of the outer ring sides (shown as outer ring side 16a). The outer ball tracks 20 are circumferentially spaced apart from each other in an equidistant relationship around the inner periphery of the outer ring 16. Each inner ball track 14 and each outer ball track 20 are radially aligned with each other in a mating relationship (also referred to as facing or paired) to define a plurality of rolling element raceways (referred to as raceways R, as is known in the art). A plurality of rolling elements 22, such as spherical balls, are disposed between the inner ring 12 and the outer ring 16, wherein at least one rolling element 22 is positioned to roll in each raceway R defined by the paired inner ball tracks 14 and outer ball tracks 20. A cage 23 is provided to guide the rolling elements 22 in their respective inner ball tracks 14 and outer ball tracks 20. Each inner ball track 14 follows an inner ball track helical path relative to the central axis 18 and has an inner ball track radius of curvature extending from one of the inner ring sides 12a to the other of the inner ring sides 12b. Each outer ball track 20 follows an outer ball track helical path relative to the central axis 18 and has an outer ball track radius of curvature extending from one of the outer ring sides 16a toward the other of the outer ring sides 16b.

[0011] The cage 23 has a plurality of recesses corresponding to the number of raceways R and rolling elements 22, assuming each recess contains only a single rolling element 22, wherein the recesses are sized to loosely receive the rolling element 22 therein. The cage 23 has an outer surface 25 sized to be received in a bore of the outer ring 16, the outer surface 25 being sized to have a tight clearance with the generally spherical radial innermost surface 30 of the outer ring 16. The cage 23 has an inner surface 27 sized to have a tight clearance with the convex radial outermost surface 32 of the inner ring 12. The outer surface 25 and the inner surface 27 extend generally axially in an arcuate profile between opposing cage sides 23a, 23b.

[0012] According to one aspect of this disclosure, at least one inner rolling member track of the inner ball track 14 may have a convex inner rolling member track curvature radius extending from side 12a to opposite side 12b, also referred to as a convex inner curvature radius, and the paired outer rolling member track curvature radii of the outer ball track 20 may have a concave outer rolling member track curvature radius extending from side 16a to opposite side 16b, also referred to as a concave outer curvature radius. Furthermore, at least one inner rolling member track of the inner ball track 14 may have a concave inner rolling member track curvature radius extending from side 12a to opposite side 12b, also referred to as a concave inner curvature radius, and the paired outer rolling member track curvature radii of the outer ball track 20 may have a convex outer rolling member track curvature radius, also referred to as a convex curvature radius.

[0013] According to one aspect of this disclosure, every other inner ball track 14 may be configured to have the aforementioned convex inner radius of curvature, wherein the paired outer ball tracks 20 have the aforementioned concave outer radius of curvature, and every other inner ball track 14 may be configured to have the aforementioned concave inner radius of curvature, wherein the paired outer ball tracks 20 have the aforementioned convex outer radius of curvature. Therefore, as needed, the convex and concave shapes of the inner ball tracks 14 may alternate, and the convex and concave shapes of the outer ball tracks 20 may alternate, wherein convex inner ball tracks 14 are paired with concave outer ball tracks 20, and concave inner ball tracks 14 are paired with convex outer ball tracks 20.

[0014] According to another aspect of this disclosure, the radius of curvature of the inner ball track, whether formed as a convex or concave inner radius of curvature, can be configured such that the radius forming the concave or convex radius of curvature is not constant. Therefore, by way of example and not limitation, the convex and concave inner radii of curvature can follow a second-order radius of curvature (also called a quadratic radius of curvature), a third-order radius of curvature, or a higher-order polynomial mathematical function. Thus, the radii of the convex and concave inner radii of curvature do not need to be constant. Similarly, the radius of curvature of the outer ball track can be configured to be non-constant, following a mathematical function similar to that of the inner ball track. Regardless of whether the inner and outer rolling member track radii of curvature are constant or non-constant, they can be configured to be equidistant from each other along their entirety, thereby providing a uniformly sized raceway R with a substantially constant distance between the profiles of the inner ball track 14 and the outer ball track 20.

[0015] According to another aspect of this disclosure, every other inner rolling member track 14 can be configured with a left-handed helix around the central axis 18, wherein the outer rolling member tracks 20 paired with the left-handed inner rolling member tracks 14 have a right-handed helix around the central axis 18. Furthermore, every other inner rolling member track 14 can be configured with a right-handed helix around the central axis 18, wherein the outer rolling member tracks 20 paired with the right-handed inner rolling member tracks 14 have a left-handed helix around the central axis 18. Therefore, when the inner ball tracks 14 have a left-handed helix, the paired outer ball tracks 16 have a right-handed helix, and vice versa.

[0016] According to another aspect of this disclosure, at least one of the inner rolling member track curvature radius of the inner ball track 14 and the outer rolling member track curvature radius of the outer ball track 20 has a radial origin offset from (also referred to as radially spaced from) the central axis 18. Therefore, the inner rolling member track curvature radius of the inner ball track 14 and / or the outer rolling member track curvature radius of the outer ball track 20 have a radial origin offset from the central axis 18. For example, the origin of the convex inner curvature radius is set in a relationship spaced from the central axis 18, wherein the central axis 18 is located between the origin and the corresponding convex inner rolling member track 14. Furthermore, the origin of the concave inner curvature radius is set in a relationship spaced from the central axis 18, wherein the inner rolling member track 14 is located between the radial origin of the concave inner curvature radius and the central axis 18. The offset of the corresponding origin of the inner rolling member track 14 relative to the central axis 18 can be combined with the inner ring 12 having all convex inner curvature radii, all concave inner curvature radii, or a mixture of convex and concave inner curvature radii.

[0017] The outer surface 25 and inner surface 27 of the cage 23 have corresponding concentric radii of curvature 34 and 36, thus sharing a common origin. The outer radius of curvature 34 is designed to form a gap with the non-cylindrical arcuate (e.g., spherical) inner surface 30 of the outer ring 16, and the inner radius of curvature 36 is greater than the radius of curvature of the convex outermost surface 32 of the inner ring 12, thereby facilitating relative pivoting motion of the inner ring 12 relative to the outer ring 16.

[0018] According to another aspect of this disclosure, the innermost surface 30 of the outer ring 16 has a region 24 with a constant radius of curvature. Figure 3 The outer ball bearing track 20 extends radially outward relative to the central axis 18 into the innermost surface 30. This is an example, not a limitation. Figure 3As shown, the constant radius of curvature region 24 has a radius origin (also called origin 26) located on the central axis 18, wherein the constant radius of curvature region 24 extends a predetermined degree range from or immediately adjacent to the side 16b of the outer ring 16 toward the opposite side 16a. Therefore, origin 26 defines a fixed center for the pivot angle of the inner ring 12 and the cage 23 relative to the outer ring 16, wherein the relative pivot angle can be set to less than approximately 30 degrees. The fixed center pivot angle of the inner ring 12 and the cage 23 relative to the outer ring 16 prevents relative axial movement between the inner and outer rings along the axis of rotation. This is ideal in applications where a pivot angle greater than 30 degrees and linear translation from axial movement are not required, where the reduced pivot angle and fixed center contribute to reduced noise, vibration, and harshness (NVH), while also reducing the overall package size and weight of the CVJ 10.

[0019] The innermost surface 30 of the outer ring 16 also has a generally truncated conical region 28 that extends from the constant radius of curvature region 24 toward the side 16a and toward the generally flat planar base 38. This is by way of example, not limitation. Figure 3 As shown, the generally truncated conical region 28 may have a generally flat conical wall that transitions to the base 38 in the fillet radius region 40, wherein the fillet radius region 40 is used to reduce stress throughout the transition between the generally truncated conical region 28 and the base 38.

[0020] Although this disclosure has been described in detail with reference to only a limited number of embodiments, it should be readily understood that this disclosure is not limited to these disclosed embodiments. Rather, this disclosure can be modified to incorporate any number of variations, alterations, substitutions, or equivalent arrangements not previously described but consistent with the spirit and scope of this disclosure. Furthermore, while various embodiments of this disclosure have been described, it should be understood that aspects of this disclosure may include only some of the described embodiments. Various elements or features of a particular embodiment are generally not limited to that particular embodiment, but are interchangeable where applicable and can be applied in chosen embodiments, even if not specifically shown or described. Therefore, this disclosure should not be considered as limited to the foregoing description.

Claims

1. A constant velocity universal joint, comprising: The inner ring has opposing inner ring sides and has a plurality of inner rolling member tracks that follow an inner rolling member track helical path relative to the rotation center axis. Each inner rolling member track has an inner rolling member track radius of curvature extending from one of the inner ring sides to the other. An outer ring, arranged around the inner ring, extends about a common rotational central axis. The outer ring has opposing outer ring sides and a plurality of outer rolling member tracks that follow a spiral path relative to the rotational central axis. Each outer rolling member track has a radius of curvature extending from one of the outer ring sides to the other. The outer rolling member tracks are arranged in pairs with the inner rolling member tracks to define a plurality of rolling member raceways. as well as At least one rolling member is disposed in each of the rolling member raceways to allow rolling reception in the inner rolling member track and the outer rolling member track. Wherein, at least one inner rolling member has a convex radius of curvature, and the paired outer rolling members have concave radii of curvature. Wherein, at least one inner rolling member has a concave radius of curvature, and the paired outer rolling members have convex radii of curvature. This allows for relative angular movement between the inner and outer rings, while preventing relative axial movement between the inner and outer rings along the axis of rotation.

2. The constant velocity universal joint according to claim 1, wherein, The inner rolling member track curvature radius of every other inner rolling member has a convex curvature radius, and the paired outer rolling member track curvature radii have concave curvature radii.

3. The constant velocity universal joint according to claim 2, wherein, The inner rolling member track curvature radius has a concave curvature radius every other one, and the paired outer rolling member track curvature radii have convex curvature radii.

4. The constant velocity universal joint according to claim 1, wherein, Every other inner rolling member track has a left-handed helix around the central axis of rotation, wherein the outer rolling member track, which is paired with the left-handed inner rolling member track, has a right-handed helix around the central axis of rotation.

5. The constant velocity universal joint according to claim 4, wherein, Every other inner rolling member track has a right-handed helix around the central axis of rotation, wherein the outer rolling member track, which is paired with the right-handed inner rolling member track, has a left-handed helix around the central axis of rotation.

6. The constant velocity universal joint according to claim 5, wherein, Every other inner rolling member track curvature radius has a convex curvature radius, wherein the corresponding outer rolling member track curvature radius paired with the convex curvature radius has a concave curvature radius.

7. The constant velocity universal joint according to claim 6, wherein, Every other inner rolling member track has a concave radius of curvature, wherein the corresponding outer rolling member track has a convex radius of curvature in pairs with the concave radius of curvature.

8. The constant velocity universal joint according to claim 1, wherein, The radius of curvature of the inner rolling component track is not constant.

9. The constant velocity universal joint according to claim 8, wherein, The radius of curvature of the outer rolling component track is not constant.

10. The constant velocity universal joint according to claim 9, wherein, The inner rolling member track curvature radius and the outer rolling member track curvature radius are equidistant from each other along their entirety.

11. The constant velocity universal joint according to claim 1, wherein, At least one of the inner rolling member track curvature radius and the outer rolling member track curvature radius has a radius origin offset from the axis of rotation center.

12. A constant velocity universal joint, comprising: The inner ring has opposing inner ring sides and has a plurality of inner rolling member tracks that follow an inner rolling member track helical path relative to the rotation center axis. Each inner rolling member track has an inner rolling member track radius of curvature extending from one of the inner ring sides to the other. An outer ring, arranged around the inner ring, extends about a common rotational central axis. The outer ring has opposing outer ring sides and a plurality of outer rolling member tracks that follow a spiral path relative to the rotational central axis. Each outer rolling member track has a radius of curvature extending from one of the outer ring sides toward the other. The outer rolling member tracks are arranged in pairs with the inner rolling member tracks to define a plurality of rolling member raceways. as well as At least one rolling member is disposed in each of the rolling member raceways to allow rolling reception in the inner rolling member track and the outer rolling member track. Wherein, the radius of curvature of at least one inner rolling member track has a radius origin offset from the axis of rotation. This allows for relative angular movement between the inner and outer rings, while preventing relative axial movement between the inner and outer rings along the axis of rotation.

13. The constant velocity universal joint according to claim 12, wherein, The axis of rotation is located between the origin of the radius of at least one inner rolling member track and the corresponding outer rolling member track.

14. The constant velocity universal joint according to claim 13, wherein, The radius of curvature of each inner rolling component track is convex.

15. The constant velocity universal joint according to claim 13, wherein, At least one inner rolling member track is located between its corresponding radius origin and the axis of rotation center.

16. The constant velocity universal joint according to claim 15, wherein, At least one inner rolling member has a convex orbital radius of curvature, and at least one inner rolling member has a concave orbital radius of curvature.

17. The constant velocity universal joint according to claim 16, wherein, The radius of curvature of every other inner rolling member track is convex, while the radius of curvature of the paired outer rolling member tracks is concave.

18. The constant velocity universal joint according to claim 12, wherein, At least one inner rolling member track is located between its corresponding radius origin and the axis of rotation center.

19. The constant velocity universal joint according to claim 18, wherein, The radius of curvature of each inner rolling component track is either concave or convex.

20. The constant velocity universal joint according to claim 18, wherein, At least one outer rolling member track is located between its corresponding radius origin and the axis of rotation center.

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