Clutch assembly and rotating system including it
The band clutch assembly addresses the challenge of high torque in electric vehicles by offering a compact, high-capacity torque transfer mechanism that passively adjusts to torque spikes, enhancing efficiency and reducing bulkiness.
Patent Information
- Application Number
- JP2025244735
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-11-04
- Filing Date
- 2025-12-10
- Publication Date
- 2026-03-04
AI Technical Summary
Modern clutch assemblies in electric vehicles face challenges due to the need for more powerful designs to handle high torque, leading to increased cost and bulkiness, necessitating a more efficient and compact solution.
A clutch assembly featuring a band clutch mechanism with a retaining band that engages with friction elements on two shafts, allowing for selective slipping and torque interruption, reducing the need for actuators and minimizing space requirements.
The band clutch assembly provides a compact, high-capacity torque transfer solution that passively adjusts to torque spikes, occupying less space and maintaining efficient rotational engagement without requiring additional actuators.
Smart Images
Figure 2026035895000001_ABST
Abstract
Description
[Technical Field]
[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This patent application claims priority to and the entire benefit of U.S. Provisional Patent Application No. 63 / 422,528, filed November 4, 2022, which is incorporated herein by reference in its entirety.
[0002] The present invention relates generally to clutch assemblies, and more particularly to clutch assemblies for use in rotating systems. [Background technology]
[0003] A typical clutch assembly is used to transfer torque from a first rotating component, e.g., a first shaft that receives rotational torque from the first torque component, to a second rotating component, e.g., a second shaft. The typical clutch assembly selectively rotatably engages and disengages the first and second rotating components to selectively transfer the rotational torque from the first shaft to the second shaft, which in turn transfers the rotational torque to at least one wheel of the vehicle. Modern electric vehicles are equipped with electric motors that can deliver higher rotational torque than ever before. In response to this, clutch assemblies are designed to be more powerful, often resulting in the need for more expensive and bulky clutch assemblies to protect the clutch assemblies from torque spikes. Summary of the Invention [Problem to be solved by the invention]
[0004] Therefore, there remains a need for an improved clutch assembly.
[0005] The clutch assembly includes a first shaft extending along a first shaft axis and rotatable about the first shaft axis, and a second shaft extending along a second shaft axis parallel to the first shaft axis and rotatable about the second shaft axis. The clutch assembly also includes a first friction element coupled to the first shaft and rotatable therewith, and a second friction element coupled to the second shaft and rotatable therewith. The clutch assembly further includes a band clutch assembly. The band clutch assembly includes a retaining band disposed around the first and second friction elements and a retaining element coupled to the retaining band. The retaining band is engageable with the first and second friction elements, and the retaining band and retaining element are rotatable together with the first and second shafts during rotation of the first and second shafts. [Brief explanation of the drawings]
[0006] [Figure 1] FIG. 1 is a perspective view of a clutch assembly and a rotating assembly including the clutch assembly. [Figure 2] FIG. 2 is a perspective view of a vehicle including two rotating assemblies. [Figure 3] FIG. 3 is a partial cross-sectional view of the clutch assembly. [Figure 4] FIG. 4 is a front view of a band clutch assembly of the clutch assembly. [Figure 5] FIG. 5 is a front view of the band clutch assembly. [Figure 6] FIG. 6 is a top view of the clutch assembly. [Figure 7] FIG. 7 is a side view of the band clutch assembly. [Figure 8] FIG. 8 is a perspective view of one embodiment of a band clutch assembly. [Figure 9] FIG. 9 is an exploded view of one embodiment of a clutch assembly. DETAILED DESCRIPTION OF THE INVENTION
[0007] Referring to the drawings, wherein like numerals indicate like parts throughout the several views, a clutch assembly 20 is generally shown in FIG. 1 . The clutch assembly 20 includes a first shaft 22 extending along and rotatable about a first shaft axis SA1, and a second shaft 24 extending along and rotatable about a second shaft axis SA2 parallel to the first shaft axis SA1. The first shaft axis SA1 may be coaxial with the second shaft axis SA2. The clutch assembly 20 typically includes a first friction element 26 coupled to and rotatable with the first shaft 22, and a second friction element 28 coupled to and rotatable with the second shaft 24. The first friction element 26 may be integral with (i.e., one piece with) the first shaft 22, or may be a separate element secured to the first shaft 22. Similarly, the second friction element 28 may be integral with the second shaft 24 (i.e., one piece) or may be a separate element secured to the second shaft 24. It should also be understood that the clutch assembly 20 may include only the first friction element 26, and the second shaft 24 may be rigidly coupled to the retaining band 32, such as via a splined connection, a welded connection, or any other suitable rigid connection, as described in further detail below. In such an embodiment, only the first shaft 22 is configured to slip relative to the retaining band 32 above a predetermined amount of torque.
[0008] The clutch assembly 20 further includes a band clutch assembly 30 including a retaining band 32 disposed around the first and second friction components 26, 28 and a retaining piece 34 coupled to the retaining band 32. The retaining band 32 is engageable with the first and second friction components 26, 28, and the retaining band 32 and retaining piece 34 are rotatable with the first and second shafts 22, 24 during rotation of the first and second shafts 22, 24. Generally, a friction material 76 is disposed on an inner surface 75 of the retaining band 32. The friction material 76 may be integral with the retaining band 32, such that the inner surface 75 has ridges, grooves, indentations, protrusions, etc. Alternatively, the friction material 76 may be a separate material from the retaining band 32 that is adhered to the inner surface 75 of the retaining band 32. It should be understood that the clutch assembly 20 may be a wet clutch assembly (i.e., including a lubricant within the clutch assembly) or a dry clutch assembly (i.e., not including a lubricant within the clutch assembly). The first and second friction components 26, 28 may be configured as disks, drums, or any other suitable configuration that allows the retaining band 32 to contact the first and second friction components 26, 28. Again, it should be understood that in some embodiments, the clutch assembly 20 may include the first friction component 26 but not the second friction component 28, and in such embodiments, the second shaft 24 may be rigidly connected to the retaining band 32, such as by a spline connection, welding, or other suitable rigid connection, such that only the first shaft 22 can slide relative to the retaining band 32.
[0009] As will be described in more detail below, the clutch assembly 20 offers several advantages. First, the clutch assembly 20 includes a retaining band 32 engageable with the first and second friction elements 26, 28, such that the retaining band 32 and the retaining element 34 are rotatable with the first and second shafts 22, 24 during rotation of the first and second shafts 22, 24, thereby allowing the clutch assembly 20 to occupy less space than other clutch assemblies, such as spring-loaded clutches. Similarly, in some embodiments, the clutch assembly 20 includes a retaining band 32 engageable with the first friction element 26 and the second shaft 24 rigidly coupled to the retaining band 32, such that the retaining band 32 and the retaining element 34 are rotatable with the first and second shafts 22, 24 during rotation of the first and second shafts 22, 24, thereby allowing the clutch assembly 20 to occupy less space than other clutch assemblies, such as spring-loaded clutches. Second, the clutch assembly 20 including the band clutch assembly 30 allows for a large retention capacity due to the contact area between the retaining band 32 and the first friction component 26, and, if present, the second friction component. More specifically, when calculating the coefficient of friction between the retaining band 32 and the first friction component 26 and, optionally, the second friction component 28, this coefficient is an exponent for the retaining band 32, resulting in a very high capacity in a small package. Third, as described in more detail below, the band clutch assembly 30 allows at least the first shaft 22 to selectively slip when a predetermined torque applied to the first shaft 22 exceeds a predetermined torque threshold. In other words, by selectively slipping the first shaft 22 when a predetermined torque applied to the first shaft 22 exceeds a predetermined torque threshold, the clutch assembly 20 functions as a torque interrupter. The torque interrupter is sometimes referred to as a mechanical fuse. Then, when the torque falls below a predetermined torque threshold, the retaining band 32 regains rotatable connection (i.e., simultaneous rotation) with the previously slipped shaft (i.e., the first shaft 22), causing the first and second shafts 22, 24 to simultaneously rotate about the first and second shaft axes SA1, SA2.During rotation of the first and second shafts 22, 24 in conjunction with the clutch assembly 20, the retaining band 32 is typically in continuous engagement with the first and second friction components 26, 28 while the first and / or second shafts 22, 24 are slipping.
[0010] In one embodiment, the clutch assembly 20 may be included in a rotating system 38 that includes a first torque component 40 coupled to the first shaft 22 to provide rotational torque to the first shaft 22. The first torque component 40 may be further defined as a first electric motor 44. The first shaft 22 may be the male member of the electric motor 44 or may be coupled to the male member of the electric motor 44. In such an embodiment, the first electric motor 44 is configured to provide rotational torque to the first shaft 22 via the band clutch assembly 30 and, in turn, to the second shaft 24. The first electric motor 44 may also receive rotational torque from the first shaft 22 via torque provided from the second shaft 24 via the band clutch assembly 30 such that the first electric motor 44 also functions as a generator. In a non-limiting example, the rotating system 38 may be further defined as a rechargeable battery electric vehicle powertrain. Rotating system 38 may be used in other applications, such as transfer cases, wind turbines, and any other suitable system having a first shaft (input shaft) and a second shaft (output shaft) coupled to each other by a band clutch assembly.
[0011] The retainer band 32 has an inner band surface 48 that faces the first friction component 26 and, if present, the second friction component 28, as shown in FIG. 5 . The inner band surface 48 has a band coefficient of friction, the first friction component 26 has a first coefficient of friction, and the second friction component 28 has a second coefficient of friction. When the first shaft 22 and the second shaft 24 are rotating, the first shaft 22 may rotate faster than the second shaft 24 if the static friction coefficient between the first friction component 26 and the inner band surface 48 is removed by a torque spike provided by the first torque component 40. Then, when torque is reduced from the first torque component 40, the retainer band 32 re-engages the first friction component 26 such that the first shaft 22, the band clutch assembly 30, and the second shaft 24 simultaneously rotate about the first and second shaft axes SA1 and SA2.
[0012] Generally, the retaining band 32 defines a band diameter BD, which remains constant during operation of the clutch assembly 20. Based on various desired parameters of the clutch assembly 20, the retaining band 32 is tightened to a desired tightness around the first and second friction components 26, 28 to achieve a desired torque capacity between the first and second friction components 26, 28 and the retaining band 32. A retaining component 34, such as a retaining clamp or retaining screw, is used to tighten and hold the retaining band 32 in engagement with the first friction component 26 and, if present, the second friction component 28. Because the clutch assembly 20 can passively adjust torque rather than actively actuate the clutch assembly 20 when the retaining band 32 is held in engagement with the first and second friction components 26, 28, the clutch assembly 20 does not require an actuator to engage and disengage the retaining band 32 from the first and second friction components 26, 28 (i.e., the clutch assembly 20 does not require an actuator to actuate the retaining band 32). Depending on the application of the clutch assembly 20 in a rotating system 38, such as a battery-powered electric vehicle powertrain, the coefficient of friction, such as through material and / or coating selection, lubricant selection if the band clutch assembly 30 is a wet clutch assembly, the tightness of the retaining band 32, the size of the retaining band 32, etc., can be adjusted to achieve the desired torque capacity and determine when torque interruption occurs.
[0013] 4, the clutch assembly 20 may include at least one balance mass 36 coupled to the retaining band 32. It is understood that any number of balance masses, such as two, three, four, etc., may be included as desired. The balance mass 36 is coupled to the retaining band 32 to help balance the mass of the clutch assembly 20 as the first shaft 22, second shaft 24, and band clutch assembly 30 rotate about the first and second axes SA1, SA2.
[0014] The rotating system 38 may be used in a vehicle 50. In such an embodiment, as shown in FIG. 2 , the vehicle 50 may include an assembly 74 including two rotating systems, such that the rotating system 38 provides rotational torque to a first wheel 52 of the vehicle 50 and the second rotating system 56 provides rotational torque to a second wheel 54 of the vehicle 50. Also, in such an embodiment, the second rotating system 56 may include a second torque component 42, such as a second electric motor 46, that provides rotational torque to the second wheel 54. It will be understood that the above description of the rotating system 38 including the clutch assembly 20 and the first torque component 40 applies to the second rotating system 56 as well.
[0015] Specifically, the second rotating system 56 may include a second clutch assembly 57 including a first shaft 58 and a second shaft 60 that are coaxially rotatable with respect to one another. The second clutch assembly 57 also includes a first friction element 62 coupled to the first shaft 58 of the second clutch assembly 57 and rotatable therewith, and a second friction element 64 coupled to the second shaft 60 of the second clutch assembly 57 and rotatable therewith. The second clutch assembly 57 further includes a second band clutch assembly 66. The second band clutch assembly 66 includes a second retaining band 68 disposed around the first and second friction elements 62, 64 of the second clutch assembly 57, and a second retaining element 70 coupled to the second retaining band 68. The second retaining band 68 is engageable with the first and second friction components 62, 64 of the second clutch assembly 57, and the second retaining band 68 and second retaining component 70 are rotatable with the first and second shafts 58, 60 of the second clutch assembly 57 during rotation of the first and second shafts 58, 60 of the second clutch assembly 57. It will be understood that the above description of the rotating system 38 including the clutch assembly 20 and the first torque component 40 equally applies to the second rotating system 56 including the second clutch assembly 57 and the second torque component 42.
[0016] The method of operating the rotating system 38 includes determining a predetermined amount of torque to be transmitted from the first torque component 40 to the first shaft 22 and calculating a coefficient of friction between the first friction component 26 and the retaining band 32 required to allow the first friction component 26 to slip relative to the retaining band 32 when the predetermined amount of torque is exceeded.
[0017] While the invention has been described in an illustrative manner, it is to be understood that the terminology used is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the invention are possible in light of the above teachings, and the invention may be practiced otherwise than as specifically described.
Claims
1. 1. A clutch assembly comprising: a first shaft extending along a first shaft axis and rotatable about the first shaft axis; a second shaft extending along a second shaft axis parallel to the first shaft axis and rotatable about the second shaft axis; a first friction element coupled to the first shaft and rotatable therewith; a second friction element coupled to the second shaft and rotatable therewith; a band clutch assembly including a retaining band disposed around the first and second friction components and a retaining component coupled to the retaining band; A clutch assembly, wherein the retaining band is engageable with the first and second friction components, and the retaining band and the retaining components are rotatable with the first and second shafts during rotation of the first and second shafts.
2. The clutch assembly of claim 1 further defined as a wet clutch assembly.
3. The clutch assembly of claim 1 further defined as a dry clutch assembly.
4. 10. A clutch assembly according to any one of the preceding claims, wherein the retaining band defines a band diameter, the band diameter remaining constant during operation of the clutch assembly.
5. The clutch assembly of any one of claims 1 to 3, wherein the retaining band continuously engages the first and second friction components during operation of the clutch assembly.
6. 4. The clutch assembly of claim 1, wherein the retaining piece secures engagement of the retaining band with the first and second friction pieces, and the retaining piece maintains a constant diameter of the retaining band.
7. The clutch assembly of any one of claims 1 to 3, wherein the retaining component is further defined as a retaining clamp.
8. The clutch assembly of any one of claims 1 to 3, wherein the retaining component is further defined as a retaining screw.
9. 4. The clutch assembly of claim 1, further comprising at least one balance mass coupled to the retaining band for balancing the retaining band during rotation of the band clutch assembly.
10. 4. The clutch assembly of claim 1, wherein the first friction component is integral with the first shaft.
11. 4. A clutch assembly according to claim 1, wherein the second friction component is integral with the second shaft.
12. 4. The clutch assembly of claim 1, wherein the retaining band has an inner band surface facing the first and second friction components, the inner band surface having a band coefficient of friction, the first friction component having a first coefficient of friction, and the second friction component having a second coefficient of friction, and when the first shaft and the second shaft are rotating, if a static coefficient of friction between the first friction component and the inner band surface is removed, the first shaft rotates faster than the second shaft.
13. A rotating system comprising the clutch assembly of any one of claims 1 to 3, further comprising a first torque component coupled to the first shaft for applying a rotational torque to the first shaft.
14. 1. An assembly comprising: A rotation system according to claim 13; a second rotating system including a second clutch assembly, the second clutch assembly including: A first shaft; a second shaft of the second clutch assembly parallel to the first shaft; a first friction element coupled to the first shaft of the second clutch assembly and rotatable therewith; a second friction element coupled to the second shaft of the second clutch assembly and rotatable therewith; a second band clutch assembly comprising: a second retaining band disposed around the first and second friction components of the second clutch assembly; and a second retaining component coupled to the second retaining band, wherein the second retaining band of the second band clutch assembly is engageable with the first and second friction components of the second clutch assembly, and the second retaining band of the second band clutch assembly and the second retaining component of the second band clutch assembly are rotatable together with the first and second shafts of the second clutch assembly during rotation of the first and second shafts of the second clutch assembly; The assembly further includes a second torque component coupled to the first shaft of the second clutch assembly for applying a rotational torque to the first shaft of the second clutch assembly.
15. 14. A method of operating a rotating system according to claim 13, comprising the steps of: determining a predetermined amount of torque to be transmitted from the first torque component to the first shaft; and calculating a coefficient of friction between the first friction component and the retaining band necessary to allow the first friction component to slip relative to the retaining band when the predetermined amount of torque is exceeded.