NL2024855B1

NL2024855B1 - A torque support assembly, a rear axle assembly comprising such a torque support assembly and bicycle comprising the rear axle assembly.

Info

Publication number: NL2024855B1
Application number: NL2024855A
Authority: NL
Inventors: Marie Van Druten Roëll
Original assignee: Advancing Tech B V
Priority date: 2020-02-07
Filing date: 2020-02-07
Publication date: 2021-09-13

Abstract

A torque support assembly, for supporting a torque of a hollow shaft onto a frame of a bicycle, comprising a cam comprising a cam hole for receiving therein a distal end of the shaft, wherein the cam hole and the shaft are interlockingly shaped for rotationally locking the cam and shaft with respect to each other, an adapter interface comprising a first face defining a seat for the cam, and an adapter interface through hole which extends from the seat on the first face and is coaxial with the cam hole for allowing a thru-axle to extend there through. The adapter interface comprises an upstanding wall, extending outward from the first face, defining an inner support surface of the seat on which the cam is supported against rotation.

Description

P125414NL00 Title: A torque support assembly, a rear axle assembly comprising such a torque support assembly and bicycle comprising the rear axle assembly.

FIELD OF THE INVENTION The invention concerns a torque support assembly, for supporting a torque of a hollow shaft onto a frame of a bicycle, a rear axle assembly comprising said torque support assembly, and a bicycle comprising said rear axle assembly.

BACKGROUND TO THE INVENTION A Flat Mount is a disc brake mounting system and an open standard for sport bicycles. In the Flat Mount Brake Assembly (FMBA) a height of the mounting surface(s) for a brake caliper relative to the mounting position of the hub axle is fixed. The mounting surface for a brake caliper is normally fixed within +/- 0.15 mm in height. The height of mounting surfaces can be chosen at the discretion of the frame builder, but is generally between 10 - 35 mm, wherein between frames differences between 10 - 35 mm can be observed quantified in steps of 5 mm. By far the majority of the current gravel and road bikes are compliant with the Flat Mount standard. Furthermore, a substantial amount of bicycle frames today seem to have a cam length of 20-25 mm. In such bicycles switching gears may occur via a fixed transmission to a shaft of a rear wheel axle, or by engaging the shaft of a rear wheel axle. Braking generally occurs by means of a caliper that engages a braking rotor that is supported on the shaft of the axle. During the replacement of a wheel, a rear wheel in particular, the fitting of a replacement wheel may be hindered by alignment issues, such as may arise when the braking caliper and braking rotor are misaligned. The person replacing the wheel would have to insert the wheel just right in order to avoid such a misalignment.

SUMMARY OF THE INVENTION It is an object of the invention to provide a torque support assembly which overcomes the above mentioned disadvantage. To this end according to an aspect there is provided a torque support assembly, for supporting a torque of a hollow shaft onto a frame of a bicycle, comprising a cam comprising a cam hole for receiving therein a distal end of the shaft, wherein the cam hole and the shaft are interlockingly shaped for rotationally locking the cam and shaft with respect to each other, an adapter interface comprising a first face defining a seat for the cam, and an adapter interface through hole which extends from the seat on the first face and is coaxial with the cam hole for allowing a thru-axle to extend there through. The adapter interface comprises an upstanding wall, extending outward from the first face, defining an inner support surface of the seat on which the cam is supported against rotation. The cam and adapter interface allow for mounting the hollow shaft to the frame, e.g. between the drop outs, such that toque can be transferred from the hollow shaft to the frame, via the cam and adapter interface. Thus, the hollow shaft can be prevented from rotating relative to the frame while transferring torque to the frame. Nevertheless, easy mounting and dismounting of the hollow shaft relative to the frame is still possible. Also, by supporting the end of the hollow shaft in the seat of the adapter interface by means of the cam the manner in which the shaft is positioned between the rear wheel (or front wheel) drop outs is pre-determined, which prevents any misalignment of brake caliper and brake rotor, also known as a brake disk. This is similarly true for the alignment of any transmission components.

The adapter interface may for example be arranged for supporting atleast some reactionary forces onto the frame via an edge of the dropout recess of the frame.

This reduces stresses on the connection with which the adapter interface is fixed to the frame such as to increase the durability of the assembly.

Optionally, the cam comprises a cam through hole.

However, it 1s also envisaged that the cam hole is an at least partially blind hole.

Optionally, the adapter interface is placed on an adapter comprising a second face, opposite the first face, for being inserted therewith into a recess of a drop out of the frame and wherein the adapter is fixable to the frame.

Optionally, the adapter interface is integrated in or with a drop out of the frame. wherein the adapter is arranged for supporting at least some torque forces onto the frame via an edge of the dropout recess of the frame.

Optionally, the adapter is arranged for supporting at least some torque forces onto the frame via the through hole of the dropout recess of the frame.

Optionally, the adapter is arranged for supporting at least some torque forces onto the frame via the brake caliper connection of the frame.

Optionally, the adapter is arranged for supporting at least some torque forces onto the frame via the thru-axle.

Optionally, the cam is arranged for supporting at least some torque forces onto the frame via the thru-axle.

The upstanding wall may further be formed as a complementary shape, also known as a counter shape, to an upper contour of the cam, such that the cam self-centers within the seat when, in use, an upward force is exerted on the cam by interaction of the upper contour of the cam and the upstanding wall.

This may save time when changing wheels, as this allows the assembly to self center when the wheel and bicycle are assembled.

It is noted that the benefit of the above feature is pronounced when the cam is attached to the hollow shaft and the adapter is fixed to the frame. The term “in use” in this context refers to the normal upright position of the bicycle.

The cam may comprise a tooth, wherein a part of the inner support surface is arranged for supporting the upper tooth surface of the cam thereon. This prevents the cam from twisting out of its seat.

The adapter may further comprises a base which, in use, i.e. when mounted to the frame, extends into a length direction of the frame, wherein the base comprises at least one screw seat, for fastening the adapter there through onto a brake caliper connection of the frame, such that the adapter through hole is aligned with the through hole in the drop out. Optionally, the adapter through hole is aligned with a resting position of the thru-axle in the drop out recess. The brake caliper connection may be a screw connection, such as with an M5 bolt. By fastening the adapter to the brake caliper connection no modifications need be made to the frame of the bicycle.

The assembly may comprise a fixable angularly adjustable connection for adjusting an angle with which the adapter is fixed the frame. The angle can be adjustable to allow the adapter through hole to be aligned with a through hole or rounded end of a shaft mounting slot in the drop out. Alternatively, or additionally, the angle can be adjustable such that the part of the inner support surface that supports the upper tooth surface of the cam is, in use, angled with respect to a horizontal plane which is smaller than a drop out angle of the shaft in the frame with respect to the same horizontal plane. This allows insertion and removal of the wheel with greater ease as the cam is guided into position under any angle greater than the angle which the inner support surface makes with respect to said horizontal plane. The horizontal plane can here be understood to be the horizontal plane with the bicycle in upright position.

According to an aspect 1s provided a rear axle assembly, comprising a torque support assembly according to any of the preceding claims, a wheel hub, and a sprocket or a plurality of sprockets rotatably mounted to the hollow shaft. The hub is rotatably mounted to the hollow shaft and the sprocket(s) are arranged for driving the hub in rotation.

Optionally, the rear axle assembly comprises a transmission between the sprocket or plurality or sprockets and the wheel hub shaft. The 5 transmission comprises at least two drives between the sprocket(s) and the hub. Hence, additional gear ratios can be provided. For instance the transmission can include a planetary gear set having a first, second and third rotational body. The first rotational body can be a ring gear, the second rotational body can be a planet carrier, and the third rotational body can be a sun gear. The ring gear can be connected to the sprocket(s) and the planet carrier can be connected to the hub. Alternatively, The ring gear can be connected to the hub and the planet carrier can be connected to the sprocket(s). In a first mode the ring gear and the planet carrier are rotationally fixed relative to each other, the transmission operates according to a first gear ratio (unity). The sun gear may in that case freewheel relative to the hollow shaft. In a second mode, the ring gear and the planet carrier are not rotationally fixed relative to each other, and the sun gear transfers torque to the hollow shaft, such that the transmission operates according to a second gear ratio. Hence, the transmission can be arranged to transfer torque to the hollow shaft. The transfer of torque requires a proper of transfer of torque from the hollow shaft to the frame, which can be achieved through the cam and adapter.

The transfer of torque from the hollow shaft via the cam to the adapter results in a support force on the adapter and a reaction force. This reaction force can hereby be supported on the frame.

The adapter may be arranged for supporting the torque onto the frame via a screw connection, such as via washers, in particular spherical or conical washers. Spherical washers come in sets having a first washer with a concave side and a second washer with a matching convex side. This allows the torque force to be supported e.g. on the the brake mount via the adapter. The upstanding wall may partly extend around the adapter through hole such that opposing parts of the supporting surface around the adapter through hole diverge from each other in a downward direction. This allows the support surface to act as a guiding surface for guiding the cam towards its correct mounting position. Additionally, the opposing parts of the supporting surface may diverge with an angle which is greater than an angle with which opposing edges of the drop out recess diverge. This allows the cam to orient itself in the adapter regardless of the angle under which it is presented to the adapter within a 180 degree range of rotation.

Optionally, the adapter comprises a boss extending from the second face arranged for resting in the dropout recess. This allows the nesting of the adapter in the drop out recess. Additionally, the upstanding wall and boss may merge at the base of the adapter, such as towards the screw seat. This allows for an increased strength of the base through which the torque is supported on the frame. This increases the durability of the adapter.

The adapter may be a monolithic element. Similarly, the cam may also be a monolithic element.

The cam and/or adapter may be made of one of stainless steel, aluminum, aluminum alloy, titanium, and titanium alloy. However, other materials can be contemplated, such as engineering plastics, surface treated steel, or the like.

Optionally, the cam and/or adapter is made of a combination of reinforced plastic and a metal, such as stainless steel, aluminum, or an alloy.

The cam hole may comprise spline teeth for interlocking with spline teeth on an outer surface of the shaft.

Optionally, the assembly is arranged for being clamped to the frame by the thru-axle. Optionally, the assembly is arranged for being clamped to the frame via a clamping end of the thru-axle.

The adapter can designed to have an installation height of 20 - 30 mm, such as 25 mm.

Optionally, the adapter holds a wireless receiver for receiving a shift signal.

Optionally, an electrical connection is arranged between the adapter, the cam, the thru-axle and/or the wheel axle.

Optionally, an electrical component is arranged on the wheel axle which is configured to be controlled by the shift signal.

According to an aspect, the invention provides for a torque support assembly, for supporting a torque of a hollow shaft onto a frame of a bicycle, comprising: a cam comprising a cam through hole for receiving therein a distal end of the shaft, wherein the cam through hole and the shaft are interlockingly shaped for rotationally locking the cam and shaft with respect to each other; an adapter comprising a first face defining a seat for the cam, a second face, opposite the first face, for being inserted therewith into a recess of a drop out of the frame, and an adapter interface through hole which extends from the seat on the first face and is to the second face coaxial with the cam through hole for allowing a thru-axle to extend there through; wherein the adapter is fixable to the frame and comprises an upstanding wall, extending outward from the first face, defining an inner support surface of the seat on which the cam is supported against rotation.

According to an aspect there is provided a bicycle comprising the rear axle assembly as described above.

It will be appreciated that any of the aspects, features and options described in view of the torque support assembly apply equally to the rear wheel assembly and the bicycle, and vice versa. It will also be clear that any one or more of the above aspects, features and options can be combined.

BRIEF DESCRIPTION OF THE DRAWINGS Further advantageous aspects of the invention will become clear from the appended description and in reference to the accompanying drawings, in which: Figure 1 shows a side view of a torque support assembly; Figure 2 shows perspective view of a shaft part for connecting to the cam of the torque support assembly; Figure 3 shows a first perspective view of an adapter of the torque support assembly; Figure 4 shows a second perspective view of the adapter of the torque support assembly; Figure 5 shows a first perspective view of the cam of the torque support assembly; Figure 6 shows a second perspective view of the cam of the torque support assembly; Figure 7 shows a side view of the adapter mounted to a rear frame part of a bicycle; Figure 8 shows a side view of the rear frame part of the bicycle; Figure 9 shows a perspective of a cam, a braking disk, and a gear box axially aligned; Figure 10 shows a perspective of the torque support assembly; Figure 11 shows perspective views of the assembly; and Figure 12 shows a schematic cross-sectional drawing of a rear axle assembly comprising a torque support assembly.

DETAILED DESCRIPTION Figure 1 shows an example of a torque support assembly 1, herein also referred to as External Torque Support (ETS) bracket. In the example of Figure 1 the torque support assembly includes an adapter 3 and a cam 5. The adapter 3 is fixable to the frame of a bicycle via a base 7. In use, the base 7 extends outward in a longitudinal direction L of the bicycle.

The cam can be seen to comprise a cam hole 9 for receiving therein a distal end 11 of a shaft S as shown in Figure 2. The hole 9 and the shaft S are in this example interlockingly shaped for rotationally locking the cam 5 and shaft S 5 with respect to each other.

To this end here the cam hole 9 has spline teeth for interlocking with spline teeth on an outer circumferential surface of the of the shaft S at the distal end 11. The adapter 3 has a first face 13 as shown in Figure 3. The first face 13 defines a seat 15 for the cam 5. The adapter 3 has a second face 17 as shown in Figure 4, opposite the first face 13. In this example the second face 17 is arranged for being inserted therewith into a recess 33 of a drop out of the frame.

The adapter 3 includes an adapter through hole 19 which extends from the seat 15 on the first face 13 to the second face 17. In mounted condition the adapter through hole 19 is coaxial with the cam hole 9 for allowing a thru-axle to extend there through.

The adapter 3 in this example has an upstanding wall 21, extending outward from the first face 13. The upstanding wall 21 defines an inner support surface 23 of the seat 15 against which the cam 5 is supported against rotation when assembled.

Figures 5 and 6 each show opposite faces of the cam 5. In this example the cam 5 is arranged such that cam hole 9 has a reduced diameter at a seating face 25. The seating face 25 is the face of the cam 5 which is to be seated in the seat 15 of the adapter 3. Due to the reduced diameter the distal end of the shaft 11 is supported in the cam 5, but is prevented from extending beyond the cam 5 to the adapter 3. Here the cam 5 can further be seen as having a tooth 27. The tooth 27 has an upper surface 29 which is arranged to be supported against the inner support surface 23 of the adapter 3. In this example each of the cam 5 and adapter 3 are a monolithic element, here made of metal.

In this example the metal is stainless steel, but this may just as well be a titanium or aluminum alloy.

It will be appreciated that other materials may be selected for the cam and/or the adapter as well.

Figure 7 shows an example of the adapter 3 of the torque support assembly 1 installed on a lower rear end of a bicycle frame 31, here at a drop out. The bicycle frame 31 in this example is compliant with the Flat Mount standard in that it comprises a drop out recess 33 which is visible in Figure

8. Figures 7 and 8 show the same rear end of the bicycle frame 31. In this example a ridge height 35 of brake mounts is 20 mm. In this example the adapter 3 is designed for a ridge height of 25 mm. This is to show that a larger adapter, designed for a 25 mm ridge height, may also fit to rear frame part with a different ridge height such as the one presented in Figures 7 and

8. Here the difference in height is compensated for by providing a spacer 39 to a screw connection with the frame 31. It is noted that such a spacer 39 will not be necessary when the adapter is fitted to a frame having a corresponding ridge height of 25 mm. Alternatively the adapter 3 may be designed such that it’s height is different, such as 15, 20, 25, 30, 35 mm. For ridge heights larger than the adapter height, a bracket (not shown, but customary) can be provided in order to facilitate a connection with the frame such that the adapter through hole 9 becomes aligned with the thru-axle through hole 19 of such a frame 31. Returning to Figure 4 in this example the adapter 3 has a boss 14, on a face opposite the face defining the seat 13 for the cam 5. The boss 14 is suitable for fitting inside the drop out recess 33, as e.g. shown in Figure 7. The boss 14 extends around the adapter through hole 9 and downwards toward the base 17 of the adapter 3. In this example, at the base 17 of the adapter 3 toward a foot, or outwardly extending end of the base 17, the boss 14 and the upstanding wall 21 merge. The adapter 3 for 25 mm ridge heights, may be designed to have a weight of about 30 grams, when made of stainless steel. The cam 5 may be designed to have a weight of about 28 grams, when made of stainless steel, or about 10 grams, when made of an aluminum alloy. It will be understood that a lower surface of the mount of the frame 31 onto which the adapter 3 may be fixed may not follow strict tolerances.

To be able to use such lower surface, in particular the brake caliper connection 37 (also herein referred to as a bolt connection), as a stop, the adapter 3 may be skewed or tilted with respect to the frame 31. The term “a stop” here meaning a surface on the frame 31 onto which the adapter 3 may support torque forces as a result of supporting torque forces of the cam 5 and corresponding shaft 11. Difference in height and skew can be compensated for by using spherical or conical washers 39 and spacers 41 added to the bolt connection with a brake caliper connection 37. As such, the adapter 3 can be brought in alignment such that the adapter through hole 9 1s coaxial with a hole 30 through the drop out. The adapter 3 can also be aligned such that the base 17 of the adapter 3 extends parallel to the bottom of the frame 31, e.g. the lower surface of the frame. This allows force to be supported across opposing surface of the frame 31 and adapter 3, and can increase durability of the connection.

Figure 7 shows an ETS angle 43 and minimum angle of entry 45. The ETS angle is defined by the upstanding wall 21. The upstanding wall 21 partly extends around the adapter through hole 19 such that opposing parts of the support surface 23 around the adapter through hole 9 diverge from each other in a downward direction D. The angle of the above divergence is the ETS angle 43. The angle which the forward portion of the support surface 23 makes with respect to a horizontal plane H is herein referred to as the minimum angle of entry 45.

A wheel is normally held between two drop out recesses 33 of the frame 31. The drop outs extend, in use, on opposite sides of the wheel. Each dropout includes a through hole 30 or a slot, e.g. having a rounded end, for allowing a thru-axle to be mounted there through. It s possible that for one wheel a bicycle comprises one torque support assembly 1. The torque support assembly can be positioned on the end of the hollow shaft adjacent the sprocket(s) or on the opposite end. It 15 also possible that the bicycle includes for one wheel two torque support assemblies, one on either side of the wheel. To this end the shaft S as shown in Figure 2 may have a second distal end designed the same as the distal end 11 shown therein.

The angle 34 of the downward sloping sides of the dropout recess 33 is such that a hub with disc can be placed without the disc jamming in / against the caliper (the caliper falls "over" and "around" the disc). This dropout angle 34 is fixed at various values for different bicycles.

By working towards ensuring that the mounting surface of the ETS bracket, also known as the adapter 3 on the frame 31 is always aligned as parallel as possible to the brake mount 37 as shown in Figure 7, an entry angle 45 in the ETS bracket can be created that is smaller than the dropout entry angle 32 of the frame itself. The total dropout angle 34 for dropout recesses 33 as shown in Figure 8 varies greatly, e.g. from 5 degrees to 40 degrees. A drop out entry angle 32, different from a dropout insertion angle 34 is also shown in Figure 8. By choosing the angle 43 of the ETS bracket beyond the range of the dropout insertion angle 34 range, it is ensured that the ETS End Cap, also known as the cam 5, will never give an obstruction to the hollow shaft S when mounting, and at the same time aligns itself as soon as the hollow shaft S reaches its final position. This is represented in Figure 10, wherein the adapter 3 is made transparent to show the ETS angle 43 with respect to the drop out insertion angle 34.

Figure 9 shows how the orientation of the ETS End cap 5 can very with respect to a horizontal through plane HT to remain guidable into its seat 15 as shown in Figure 7. The ETS End Cap 5 (cam), aligns itself in the ETS Bracket 3 (adapter), regardless of the angle at which it is offered provided the adapter 3 1s presented in a manner concordant with Figure 9). The alignment can be seen in Figure 11 where the support surface 23 guides the cam 5 into alignment with the adapter 3 such that the cam and adapter through holes 9, 19 are coaxial.

Figure 12 shows a schematic cross section of a rear (wheel) axle assembly 100. In Figure 12 the wheel axle assembly 100 is mounted in a rear frame 31 of a bicycle. The axle assembly 100 is mounted between two dropouts 104 of the frame 31. The wheel axle assembly 100 includes a thru- axle 106 for securing the wheel axle assembly 100 to the frame 31. The thru- axle 106 here is inserted through the hollow shaft S. The torque support assembly 1 is interposed between the dropout 104 and the hollow shaft S on the side opposite the sprockets.

In this example, the wheel axle assembly 100 includes a hub 108. The wheel axle assembly 100 includes a driver 110 for driving the hub in rotation via a transmission 114. Here the driver 110 includes a cassette 112 including a plurality of sprocket gears. The transmission 114 is also coupled to the shaft S. The shaft S prevented from rotating around its longitudinal axis by means of the torque support assembly. The transmission 114 may interact with a support element 130, such as spline teeth, on the shaft S. This allows gear shifting torque to be exerted onto the shaft S which is supported by the torque support assembly 1 onto the frame 31.

Herein, the invention is described with reference to specific examples. It will, however, be evident that various modifications and changes may be made therein, without departing from the essence of the invention. For the purpose of clarity and a concise description features are described herein as part of the same or separate embodiments, however, embodiments having combinations of all or some of the features described in these separate examples are also envisaged.

In the example of Figure 12 one torque support assembly is mounted on the end of the shaft opposite the sprockets. It will be clear that it is also possible to mount one torque support assembly on the side of teh shaft adjacent the sprockets. It is also possible to mount a torque support assembly on each end of the shaft.

In a described example, the transmission includes a planetary gear with a sun wheel, planet carrier for planet gears and ring gear. It will be appreciated that it 1s also possible that the planetary gear includes two sun gears and two sets of planet gears.

However, other modifications, variations, and alternatives are also possible. The specifications, drawings and examples are, accordingly, to be regarded in an illustrative sense rather than in a restrictive sense.

For the purpose of clarity and a concise description features are described herein as part of the same or separate embodiments, however, it will be appreciated that the scope of the invention may include embodiments having combinations of all or some of the features described.

In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word ‘comprising’ does not exclude the presence of other features or steps than those listed in a claim. Furthermore, the words ‘a’ and ‘an’ shall not be construed as limited to ‘only one’, but instead are used to mean ‘at least one’, and do not exclude a plurality. The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to an advantage.

Claims

Conclusions

A torque assist assembly for supporting a torque of a hollow shaft on a bicycle frame, comprising: a cam including a cam hole for receiving a distal end of the shaft therein, the cam hole and the shaft interlocking are designed to be gripping for rotational locking of the cam and the shaft relative to each other; an adapter coupling comprising a first face defining a seat for the cam, and an adapter through-hole extending from the seat on the first face and being coaxial with the cam hole to allow a stub shaft to extend therethrough wherein the adapter coupling includes an upstanding wall extending outwardly from the first face defining an inner bearing surface of the seat on which the cam is supported against rotation.

The assembly of claim 1, wherein the adapter coupling is disposed on an adapter comprising a second face, opposite the first face, for insertion therewith into a recess of a dropout of the frame and wherein the adapter is securable to the frame.

The assembly of claim 1 or 2, wherein the adapter coupling is integrated in or with a dropout of the frame.

The assembly of claim 2 or 3, wherein the adapter is adapted to support at least some coupling forces on the frame via an edge of the dropout recess of the frame.

The assembly of any one of claims 2-4, wherein the adapter is adapted to support at least some coupling forces on the frame through the through hole of the dropout recess of the frame.

The assembly according to any one of claims 2-5, wherein the adapter 1s is adapted to support at least some coupling forces on the frame via the caliper connection of the frame.

The assembly according to any one of claims 2-6, wherein the adapter 1s is adapted to support at least some coupling forces on the frame via the stub axle.

The assembly according to any one of claims 1-7, wherein the cam is adapted to support at least some coupling forces on the frame via the stub axle.

The assembly of any one of claims 1-8, wherein the upstanding wall 1s is formed as a shape complementary to an upper contour of the cam such that the cam self-centers within the seat when, in use, an upward force is applied. on the ridge by interaction of the upper contour of the ridge and the upright wall.

The assembly according to any one of claims 1-9, wherein a part of the inner supporting surface is adapted for supporting an upper tooth surface of the cam thereon.

The assembly of claim 10, wherein the adapter includes a base which, in use, extends in a longitudinal direction of the frame, the base 1s including at least one screw seat for securing the adapter therethrough to a caliper connection of the frame such that the adapter through hole aligns 1s with the through hole in the dropout.

The assembly of claim 11, including a lockable angle-adjustable joint for adjusting an angle at which the adapter is secured to the frame.

The assembly of claim 11 or 12, wherein the adapter is adapted to support the torque on the frame via a screw connection, such as via washers.

The assembly of any one of claims 1 to 13, wherein the upstanding wall extends partially around the adapter through-hole such that opposing portions of the support surface around the adapter through-hole extend relative to each other in a downward direction. .

The assembly of claim 14, wherein the opposing portions of the support surface diverge at an angle greater than an angle at which opposing edges of the dropout recess diverge.

The assembly of any one of claims 1-15, wherein the adapter includes a boss extending from the second face adapted to rest in the dropout recess.

The assembly of at least claim 16, wherein the upstanding wall and boss meet at the base of the adapter, such as toward the screw seat.

The assembly of any preceding claim, wherein the adapter is a monolithic element.

The assembly of any preceding claim, wherein the cam and/or adapter is made of one of: stainless steel, aluminum, aluminum alloy, and titanium alloy.

The assembly of any of the preceding claims, wherein the cam and/or adapter is made from a combination of reinforced plastic and a metal, such as stainless steel, aluminum, or an alloy.

The assembly of any of the preceding claims, wherein the through-hole of the cam is splined for engagement with splined teeth on an outer surface of the shaft.

The assembly according to any one of the preceding claims, adapted to be clamped to the frame by the stub axle.

The assembly according to any of the preceding claims, wherein the adapter has an installation height of 20 - 30 mm, such as 25 mm.

The assembly according to one or more of the preceding claims, wherein the adapter comprises a wireless receiver for receiving a shift signal.

The assembly according to one or more of the preceding claims, wherein an electrical connection is provided between the adapter, the cam, the stub axle and/or the wheel axle.

The assembly according to any one of the preceding claims, wherein an electrical component is provided on the wheel axle which is controlled by the shift signal.

A rear axle assembly comprising a torque assist assembly according to any one of claims 1 to 26, a wheel hub, and a sprocket or plurality of sprockets pivotally mounted to the hollow shaft.

The rear axle assembly of claim 24, comprising a transmission between the sprocket or plurality of sprockets and the wheel hub.

The rear axle assembly of claim 25, wherein the transmission is configured to transmit torque to the hollow shaft.

A bicycle comprising the rear axle assembly according to any one of claims 27-29.