Bicycle middle axle

Abstract

The invention provides a bicycle center shaft. The bicycle center shaft comprises a main shaft, a torque reaction sleeve, a transmission sleeve and a magnetic field sensor. The main shaft is provided with a rotating shaft and two crank connecting ends. The torque reaction sleeve is sleeved on the main shaft and is provided with a first connecting end and a second connecting end. The first connecting end is connected with the main shaft. The torque reactive sleeve has a permanent magnet magnetoelastic region surrounding the rotating shaft. The permanent magnet magnetoelastic region is distributed on a reference plane. The transmission sleeve is sleeved on the main shaft and is provided with a third connecting end and a fluted disc support connecting end. And the third connecting end is connected with the second connecting end. The magnetic field sensor is arranged corresponding to the permanent magnet magnetoelastic area. The magnetic field sensor senses the magnetic field of the permanent magnet magnetoelastic area.

Description

Technical Field

[0001] The present invention relates to the field of bicycles, and in particular to a bicycle middle shaft with a torque sensing function. Background Art

[0002] Bicycle-related applications, such as power calculation and electric power steering, often require torque sensing technology. Typically, a torque sensor is installed at the bicycle's center axle to detect the torque applied to the chainring bracket by the user via the pedals, cranks, and the spindle connecting the left and right cranks. While torque sensors currently exist that utilize inverse magnetostriction, their accuracy still needs improvement.

[0003] Therefore, it is necessary to design a novel bicycle center shaft to overcome the above-mentioned defectives. Summary of the Invention

[0004] The object of the present invention is to provide a bicycle axle having a torque sensing function utilizing inverse magnetostriction, wherein the magnetoelastic region of the permanent magnet of the sensing target is distributed obliquely to improve the torque sensing accuracy.

[0005] To achieve the above object, the present invention provides a bicycle bottom bracket, comprising a main shaft having a rotation axis, a first crank connecting end, and a second crank connecting end;

[0006] a torque reaction sleeve having a first connecting end and a second connecting end, wherein the torque reaction sleeve is sleeved on the main shaft, the first connecting end being connected to the main shaft, and the torque reaction sleeve having a first permanent magnet magnetoelastic region surrounding the rotating shaft, the first permanent magnet magnetoelastic region being distributed on a first reference plane;

[0007] a transmission sleeve having a third connecting end and a geared disc bracket connecting end, the transmission sleeve being sleeved on the main shaft, the third connecting end being connected to the second connecting end; and

[0008] The first magnetic field sensor is provided corresponding to the magnetoelastic region of the first permanent magnet, and senses the magnetic field of the magnetoelastic region of the first permanent magnet.

[0009] Preferably, the first reference plane is perpendicular to the rotation axis.

[0010] Preferably, the first reference plane is not perpendicular to the rotation axis.

[0011] Preferably, the angle between the first reference plane and the rotation axis is 45 degrees.

[0012] Preferably, it further includes a second magnetic field sensor, wherein the torque reaction sleeve has a second permanent magnet magnetoelastic zone surrounding the rotating axis, the second permanent magnet magnetoelastic zone is distributed on a second reference plane, the second reference plane is not perpendicular to the rotating axis and is not parallel to the first reference plane, the second magnetic field sensor is arranged corresponding to the second permanent magnet magnetoelastic zone, and the second magnetic field sensor senses the magnetic field of the second permanent magnet magnetoelastic zone.

[0013] Preferably, the first reference plane is perpendicular to the second reference plane.

[0014] Preferably, the magnetic field of the first permanent magnet magnetoelastic region is in the same direction or in the opposite direction as the magnetic field of the second permanent magnet magnetoelastic region.

[0015] Preferably, the first magnetic field sensor includes an induction coil, an inductor, a Hall element or a magnetoresistive element.

[0016] Preferably, the bicycle axle further comprises:

[0017] A magnetic ring, wherein the magnetic ring is fixed around the main shaft and has a protrusion, and the protrusion is parallel to the rotation axis;

[0018] a third magnetic field sensor, the third magnetic field sensor being disposed corresponding to the magnetic ring and sensing the magnetic field of the magnetic ring; and

[0019] A fourth magnetic field sensor is provided corresponding to the protrusion and senses a magnetic field of the protrusion.

[0020] Preferably, the torque reaction sleeve comprises a sleeve body, and the first permanent magnet magnetoelastic region is fixed on the sleeve body; wherein the sleeve body is non-magnetic.

[0021] Preferably, the device further comprises a fifth magnetic field sensor, which is arranged corresponding to the magnetoelastic region of the first permanent magnet, and the fifth magnetic field sensor senses the magnetic field of the magnetoelastic region of the first permanent magnet.

[0022] Preferably, the shear modulus of the torque reaction sleeve is smaller than the shear modulus of the main shaft and the transmission sleeve.

[0023] Compared with the prior art, the bicycle bottom bracket provided by the present invention includes a torque reaction sleeve and a transmission sleeve that are sleeved on the main shaft. The first connecting end of the torque reaction sleeve is connected to the main shaft, the second connecting end is connected to one end of the transmission sleeve, and the other end of the transmission sleeve is connected to the chainring bracket. In this way, the torque received by the torque reaction sleeve from the main shaft can be fully transmitted to the chainring bracket by the transmission sleeve, and the permanent magnet magnetoelastic zone on the torque reaction sleeve can accurately reflect the torque received by the chainring bracket.

[0024] In addition, by setting the first permanent magnet magnetoelastic zone on the torque reaction sleeve at an angle, when the torque reaction sleeve is subjected to torque, the first permanent magnet magnetoelastic zone can produce a larger magnetic field change, thereby improving the accuracy of the first permanent magnet magnetoelastic zone in reflecting the torque transmitted by the torque reaction sleeve, thereby effectively improving the torque sensing accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 FIG. 1 is a schematic side view of a bicycle according to an embodiment.

[0026] Figure 2 for Figure 1 Schematic diagram of a bicycle bottom bracket for a mid-size bicycle.

[0027] Figure 3 for Figure 2 A cross-section of a bicycle's bottom bracket.

[0028] Figure 4 for Figure 2 Exploded view of a bicycle's bottom bracket.

[0029] Figure 5 Schematic diagram of axial unipolar magnetization.

[0030] Figure 6 Schematic diagram of radial monopole magnetization.

[0031] Figure 7 for Figure 4 Schematic diagram of a medium torque reaction sleeve.

[0032] Figure 8 For use Figure 7 Schematic diagram of the torque-sensing sleeve using an induction coil as a sensor. DETAILED DESCRIPTION

[0033] In order to provide a further understanding of the purpose, structure, features, and functions of the present invention, the present invention is described in detail below with reference to the embodiments.

[0034] Certain terms are used throughout the specification and claims to refer to specific components. Those skilled in the art will understand that manufacturers may use different terms to refer to the same component. This specification and claims do not distinguish components by name, but rather by their functional differences. Throughout the specification and claims, the term "including" is open-ended and should be interpreted as meaning "including, but not limited to."

[0035] See also Figure 1 and Figure 2A bicycle 1 according to one embodiment includes a frame 12, a bicycle bottom bracket 14, a right crank 16a, a left crank 16b, a chainring bracket 18, and other components not labeled or shown in the figures (including a front wheel, a rear wheel, a chain, a seat, handlebars, and other bicycle accessories). The bicycle bottom bracket 14 is mounted within a bottom hole at the bottom of the frame 12. The right crank 16a and the left crank 16b are connected to the two ends of the bicycle bottom bracket 14, respectively. The chainring bracket 18 is connected to the bicycle bottom bracket 14 independently of the right crank 16a and the left crank 16b. Torque input through the right crank 16a and the left crank 16b (e.g., by a user pedaling on the right crank 16a and the left crank 16b) is transmitted through the bicycle bottom bracket 14 to the chainring bracket 18 (which has a gear ring (e.g., a modular design or integral molding) and is connected to the chain). The bicycle bottom bracket 14 can sense the torque transmitted to the chainring bracket 18. This sensed signal can be transmitted to a controller (not shown in the figure, for example, fixed to the frame 12 or inside the tube) for use by other devices. For example, the torque value can be displayed on a display electrically connected to the controller and mounted on the handlebars. Another example is controlling the operation of the motor based on this sensed signal (for example, when the bicycle 1 is used as an electric bicycle).

[0036] See also Figure 3 and Figure 4 . The bicycle bottom bracket 14 mainly includes a shell 140, a main shaft 142, a torque reaction sleeve 144, a transmission sleeve 146 and a circuit board module 148. The bicycle bottom bracket 14 passes through the five-way hole of the frame 12 as a whole and is fixed to the frame 12 via fixing covers 150a and 150b. The shell 140 is fixedly arranged in the five-way hole of the frame 12 via fixing covers 150a and 150b; wherein, the fixing covers 150a and 150b have external threads, which engage with the internal threads in the five-way hole to fix the fixing covers 150a and 150b on the frame 12. The shell 140 is tubular as a whole. A plurality of positioning grooves 1402 are provided on the outer surface of one end of the shell 140 close to the fixing cover 150b, and the fixing cover 150b correspondingly has a plurality of protrusions 1502. The protrusions 1502 are inserted into the positioning grooves 1402 to prevent the shell 140 from rotating relative to each other. The circuit board module 148 is fixed to the inner side of the housing 140. The housing 140 has a through hole for a connecting wire 152 (cable or wire harness) connected to the circuit board module 148 to pass through, thereby electrically connecting to the aforementioned controller.

[0037] The spindle 142 passes through the fixing cover 150b, the housing 140, and the fixing cover 150a. It has a rotating axis 142a, a first crank connection end 1422, and a second crank connection end 1424. The right crank 16a and the left crank 16b are detachably connected to the first crank connection end 1422 and the second crank connection end 1424, respectively. In this embodiment, these connections are achieved via a spline connection, but the present invention is not limited to this. This allows the first crank connection end 1422 and the second crank connection end 1424 to directly transmit torque to the spindle 142. Furthermore, a bearing 154b is disposed inside the fixing cover 150b of the bicycle bottom bracket 14. The fixing cover 150b supports the spindle 142 via the bearing 154b.

[0038] The torque response sleeve 144 is mounted on the main shaft 142. The torque response sleeve 144 is generally tubular and includes a sleeve body 1440, a first connection end 1442, and a second connection end 1444. The main shaft 142 has a raised ring 1426 in the middle of the main body. The sleeve body 1440 of the torque response sleeve 144 is mounted on the main shaft 142. The first connection end 1442 of the torque response sleeve 144 is connected to the main shaft 142 and abuts against the raised ring 1426 of the main shaft 142. This connection is achieved via a spline connection, wherein a spline is formed on the main shaft 142 adjacent to the raised ring 1426, and a keyway is formed in the wall of the sleeve body 1440 (located at the first connection end 1442), but this is not a limitation in practice. The raised ring 1426 serves to limit the torque response sleeve 144 in the axial direction (parallel to the rotation axis 142a). Thus, the main shaft 142 can directly transmit torque to the torque reaction sleeve 144. In addition, the torque reaction sleeve 144 further comprises a first permanent magnet magnetoelastic region 1446 and a second permanent magnet magnetoelastic region 1448, both of which are fixed to the sleeve body 1440 around the rotating shaft 142a.

[0039] The transmission sleeve 146 is sleeved onto the main shaft 142. The transmission sleeve 146 is generally tubular and includes a sleeve body 1460, a third connecting end 1462, and a gear support connecting end 1464. The sleeve body 1440 of the torque reaction sleeve 144 has a raised ring 1441. The sleeve body 1460 of the transmission sleeve 146 is sleeved onto the main shaft 142 and passes through the fixing cover 150a. The third connecting end 1462 of the transmission sleeve 146 is connected to the second connecting end 1444 of the torque reaction sleeve 144 and abuts the raised ring 1441 of the sleeve body 1440. This connection is achieved by a spline connection, wherein a spline is formed on the sleeve body 1440 adjacent to the raised ring 1441, and a keyway is formed on the wall of the sleeve body 1460 (located at the third connecting end 1462), but this is not limited to this embodiment. The protruding ring 1441 can limit the position of the transmission sleeve 146 in the axial direction (parallel to the rotation axis 142a). This allows the torque-receiving sleeve 144 to directly transmit torque to the transmission sleeve 146. Furthermore, within the bicycle bottom bracket 14, a bearing 154a is disposed inside the fixing cover 150a. The fixing cover 150a supports the sleeve body 1460 of the transmission sleeve 146 via the bearing 154a.

[0040] Furthermore, the sprocket bracket 18 is connected to the sprocket bracket connection end 1464 of the transmission sleeve 146 via a splined connection. The spline is formed on the sleeve body 1460 of the transmission sleeve 146 (located at the sprocket bracket connection end 1464), and a keyway is formed in the wall of the sprocket bracket 18, but this is not the only practical limitation. This allows the transmission sleeve 146 to directly transmit torque to the sprocket bracket 18, thereby driving the chain through the sprocket bracket 18 to drive the rear wheel. Furthermore, in this embodiment, a retaining ring 156 is screwed onto the transmission sleeve 146 (e.g., via a threaded structure (not shown)) to secure the sprocket bracket 18 to the transmission sleeve 146.

[0041] In this embodiment, the torque response sleeve 144 is connected to the main shaft 142 only via its first connection end 1442, and to the transmission sleeve 146 (its third connection end 1462) only via its second connection end 1444. In principle, the torque response sleeve 144, with the exception of the first connection end 1442, does not contact the main shaft 142. In principle, the transmission sleeve 146 also does not contact the main shaft 142, or there is no connection between the main shaft 142 that can directly transmit torque (for example, the two are separated; or, for example, lubricant is present between the two to eliminate or significantly reduce friction between the two to a negligible level). Furthermore, in principle, the bearings 154a and 154b do not affect torque transmission. Thus, the torque transmitted from the right crank 16a and the left crank 16b to the main shaft 142 can, in principle, only be transmitted to the sprocket bracket 18 via the torque reaction sleeve 144 and the transmission sleeve 146 in that order. Furthermore, in principle, all the torque received by the torque reaction sleeve 144 from the main shaft 142 can be transmitted to the sprocket bracket 18. The first permanent magnet magnetoelastic region 1446 and the second permanent magnet magnetoelastic region 1448 on the torque reaction sleeve 144 can accurately reflect the torque received by the sprocket bracket 18.

[0042] In this embodiment, the circuit board module 148 includes a circuit board 1480, a first magnetic field sensor 1482 and a second magnetic field sensor 1484 disposed on the circuit board 1480, and other electronic components (e.g., a processor, a connector, etc.). The first magnetic field sensor 1482 and the second magnetic field sensor 1484 are disposed opposite the first permanent magnet magnetoelastic region 1446 and the second permanent magnet magnetoelastic region 1448, respectively. The first magnetic field sensor 1482 senses the magnetic field of the first permanent magnet magnetoelastic region 1446. The second magnetic field sensor 1484 senses the magnetic field of the second permanent magnet magnetoelastic region 1448. When the torque reaction sleeve 144 is subjected to torque, the first permanent magnet magnetoelastic region 1446 and the second permanent magnet magnetoelastic region 1448 thereon will also be subjected to some of the torque, which means that stress will be generated in the first permanent magnet magnetoelastic region 1446 and the second permanent magnet magnetoelastic region 1448. According to the inverse magnetostriction phenomenon, when the stress on the first permanent magnet magnetoelastic region 1446 and the second permanent magnet magnetoelastic region 1448 changes, the magnetic field characteristics (such as direction, value, etc.) will also change. This magnetic field change can be sensed by the first magnetic field sensor 1482 and the second magnetic field sensor 1484. In addition, in this embodiment, a wavy spring washer 143 (marked at Figure 3(center), that is, the first connection end 1442 is tightly pressed against the raised ring 1426 in the axial direction (parallel to the rotation axis 142a) via the spring washer 143. This structural configuration facilitates precise axial alignment of the first magnetic field sensor 1482, the second magnetic field sensor 1484, and the magnetic field sensors 1483 and 1485 disposed on the circuit board module 149 with the first permanent magnet magnetoelastic region 1446 and the second permanent magnet magnetoelastic region 1448. Therefore, the provision of the spring washer 143 reduces the difficulty of assembly caused by dimensional tolerances.

[0043] In practice, the first magnetic field sensor 1482 and the second magnetic field sensor 1484 can be inductors, Hall elements, magnetoresistive elements (e.g., anisotropic magnetoresistive (AMR) sensors, giant magnetoresistive (GMR) sensors, tunnel magnetoresistive (TMR) sensors, tunnel junction magnetoresistive (MTJ) sensors), or other elements capable of sensing magnetic fields. The first permanent magnet magnetoelastic region 1446 and the second permanent magnet magnetoelastic region 1448 can be integrated with the sleeve body 1440 through methods such as interlocking, bonding, press-fitting, or insert molding. The sleeve body 1440 can be non-magnetic (to prevent the first permanent magnet magnetoelastic region 1446 and the second permanent magnet magnetoelastic region 1448 from being affected by magnetic noise from additional magnetic fields). The first permanent magnet magnetoelastic region 1446 and the second permanent magnet magnetoelastic region 1448 can protrude from the sleeve body 1440 or be flush with the surface of the sleeve body 1440. The first permanent magnet magnetoelastic region 1446 (or the second permanent magnet magnetoelastic region 1448) can be axially magnetized or radially magnetized. The former means that the magnetic field direction is parallel to the rotation axis 142a, such as axial monopole magnetization (such as Figure 5 The latter is that the magnetic field direction is perpendicular to the rotation axis 142a, for example, the radial inner and outer rings are unipolar magnetized (as shown in FIG. Figure 6 (As shown). The magnetization modes of the first permanent magnet magnetoelastic region 1446 and the second permanent magnet magnetoelastic region 1448 are not limited to being the same. Furthermore, the magnetic field of the first permanent magnet magnetoelastic region 1446 and the magnetic field of the second permanent magnet magnetoelastic region 1448 can be in the same direction or in opposite directions.

[0044] like Figure 7As shown, in this embodiment, the first permanent magnet magnetoelastic region 1446 is distributed on a first reference plane P1 (indicated by a two-dot chain line in the figure). The first reference plane P1 is not perpendicular to the rotation axis 142a (its position relative to the torque reaction sleeve 144 is indicated by a two-dot chain line in the figure). The second permanent magnet magnetoelastic region 1448 is distributed on a second reference plane P2 (indicated by a two-dot chain line in the figure). The second reference plane P2 is not perpendicular to the rotation axis 142a. The first reference plane P1 and the second reference plane P2 are not parallel. The first permanent magnet magnetoelastic region 1446 (or second permanent magnet magnetoelastic region 1448) is arranged at an angle. This allows the first permanent magnet magnetoelastic region 1446 (or second permanent magnet magnetoelastic region 1448) to generate a larger magnetic field change when the torque reaction sleeve 144 is subjected to torque. This improves the accuracy with which the first permanent magnet magnetoelastic region 1446 (or second permanent magnet magnetoelastic region 1448) reflects the torque transmitted by the torque reaction sleeve 144, thereby indirectly improving the accuracy of calculating the torque received by the sprocket bracket 18. In principle, the torque transmitted by the torque reaction sleeve 144 is the torque received by the sprocket bracket 18. In practice, the angle between the first reference plane P1 (or second reference plane P2) and the rotation axis 142a can be 45 degrees (or 135 degrees). The first reference plane P1 and the second reference plane P2 can also be perpendicular to each other.

[0045] Furthermore, in this embodiment, when the torque-reacting sleeve 144 receives torque from the main shaft 142, the sleeve body 1440 undergoes (elastic) deformation. The first permanent magnet magnetoelastic region 1446 and the second permanent magnet magnetoelastic region 1448, fixedly coupled to the sleeve body 1440, also undergo (elastic) deformation, generating magnetic field changes due to the piezomagnetic effect. The tubular shape of the torque-reacting sleeve 144 allows for greater deformation (or stress), which helps improve the accuracy with which the first permanent magnet magnetoelastic region 1446 (or the second permanent magnet magnetoelastic region 1448) reflects the torque transmitted by the torque-reacting sleeve 144. In addition, the first permanent magnet magnetoelastic zone 1446 and the second permanent magnet magnetoelastic zone 1448 are both located on the outer surface of the sleeve body 1440, so they can produce larger deformation (or stress), which is also beneficial to improving the accuracy of the first permanent magnet magnetoelastic zone 1446 (or the second permanent magnet magnetoelastic zone 1448) in reflecting the torque transmitted by the torque reaction sleeve 144.

[0046] In addition, you can refer to Figure 3In this embodiment, the torque received by the bicycle bottom bracket 14 from the cranks 16a and 16b is transmitted to the chainring bracket 18 in sequence via the main shaft 142, the torque reaction sleeve 144, and the transmission sleeve 146. The transmission sleeve 146 is supported by the bearing 154a and connected to the chainring bracket 18. Therefore, the transmission sleeve 146 should generally have a certain degree of rigidity to prevent significant elastic deformation. The main shaft 142 is supported by the bearing 154b and connected to the cranks 16a and 16b. Therefore, the main shaft 142 should also generally have a certain degree of rigidity. The torque reaction sleeve 144 is used to sense torque. Therefore, based on the sensing mechanism of the bicycle bottom bracket 14, the torque reaction sleeve 144 can adopt a structure that is easier to deform to increase the accuracy of the permanent magnet magnetoelastic regions 1446 and 1448 in sensing the torque transmitted by the torque reaction sleeve 144; for example, a torque reaction sleeve 144 with a smaller overall shear modulus (smaller than the shear modulus of the main shaft 142 and the transmission sleeve 146) can be used.

[0047] In addition, in practice, the first magnetic field sensor 1482 and the second magnetic field sensor 1484 may also be induction coils. Figure 8 As shown (its viewing angle is the same as Figure 7 The first magnetic field sensor 1482' and the second magnetic field sensor 1484' are implemented by induction coils, correspondingly surrounding the first permanent magnet magnetoelastic region 1446 and the second permanent magnet magnetoelastic region 1448 (wherein the second permanent magnet magnetoelastic region 1448 is covered by the induction coil and is not shown in the figure).

[0048] In this embodiment, if Figure 3 and Figure 4 As shown, bicycle bottom bracket 14 further includes another circuit board module 149, which has a substantially identical structure to circuit board module 148 and is disposed on opposite sides of torque response sleeve 144 relative to rotation axis 142a. Circuit board module 149 also includes a fifth magnetic field sensor 1483 and a magnetic field sensor 1485 for respectively sensing the magnetic fields of first permanent magnet magnetoelastic region 1446 and second permanent magnet magnetoelastic region 1448. Furthermore, in practice, magnetic field sensors 1482, 1483, 1484, and 1485 are not limited to using the same type of sensor, nor are they limited to being implemented with a single sensor (e.g., a combination of an induction coil and a Hall effect sensor). Furthermore, for the same permanent magnet magnetoelastic region, two or more or different magnetic effect sensors can be used simultaneously to perform signal measurement, differential calculation, calibration compensation and other functions, thereby improving the accuracy of sensing the torque transmitted by the torque reaction sleeve 144 through the permanent magnet magnetoelastic region, thereby indirectly improving the accuracy of calculating the torque received by the gear disc bracket 18.

[0049] In addition, in this embodiment, Figure 3 and Figure 4As shown, the bicycle bottom bracket 14 also has a speed sensing function. The bicycle bottom bracket 14 further includes a magnetic ring 158, and a third magnetic field sensor 1486 and a fourth magnetic field sensor 1488 disposed on a circuit board 1480 of the circuit board module 148. The magnetic ring 158 is fixedly mounted around the main shaft 142. The magnetic ring 158 has an annular body surrounding the main shaft 142 and a protrusion 1582 extending from the annular body parallel to the rotation axis 142a. The third magnetic field sensor 1486 is disposed opposite the annular body of the magnetic ring 158. The fourth magnetic field sensor 1488 is disposed opposite the protrusion 1582. The annular body of the magnetic ring 158 has a plurality of magnet segments distributed around the main shaft 142, with adjacent magnet segments having different magnetic field directions. In practice, this magnetic structure distribution can be achieved through axial magnetization. The third magnetic field sensor 1486 senses the magnetic field of the ring 158 and calculates the rotational speed of the spindle 142. In other words, the third magnetic field sensor 1486 is used for speed (or rotational speed) detection. The fourth magnetic field sensor 1488 senses the magnetic field of the protrusion 1582. This sensing signal can be used as a positioning signal for the spindle 142. In other words, the fourth magnetic field sensor 1488 is used for zero point detection.

[0050] As previously described, bicycle bottom bracket 14 can simultaneously sense torque, static and dynamic torque, angular position, cadence, and other parameters on both its left and right sides. Its torque sensing is sensitive and highly linear. Furthermore, in the aforementioned embodiment, both first reference plane P1 and second reference plane P2 are non-perpendicular to and non-parallel to the rotation axis 142a, but this is not a limitation. For example, in one embodiment, first reference plane P1 and / or second reference plane P2 are both perpendicular to the rotation axis 142a; in another embodiment, first reference plane P1 and second reference plane P2 are parallel.

[0051] The present invention has been described with reference to the above embodiments. However, the above embodiments are merely exemplary embodiments of the present invention. It should be noted that the disclosed embodiments do not limit the scope of the present invention. On the contrary, modifications and improvements that do not depart from the spirit and scope of the present invention are intended to be protected by the present invention.

Claims

1. A bicycle middle shaft, characterized in that: include: A main shaft having a rotating shaft, a first crank connecting end, and a second crank connecting end; a torque reaction sleeve having a first connecting end and a second connecting end, wherein the torque reaction sleeve is sleeved on the main shaft, the first connecting end being connected to the main shaft, and the torque reaction sleeve having a first permanent magnet magnetoelastic region surrounding the rotating shaft, the first permanent magnet magnetoelastic region being distributed on a first reference plane; a transmission sleeve having a third connecting end and a geared disc bracket connecting end, the transmission sleeve being sleeved on the main shaft, the third connecting end being connected to the second connecting end; and The first magnetic field sensor is provided corresponding to the magnetoelastic region of the first permanent magnet, and senses the magnetic field of the magnetoelastic region of the first permanent magnet.

2. The bicycle bottom bracket according to claim 1, wherein: The first reference plane is perpendicular to the rotation axis.

3. The bicycle bottom bracket according to claim 1, wherein: The first reference plane is not perpendicular to the rotation axis.

4. The bicycle bottom bracket according to claim 3, wherein: The included angle between the first reference plane and the rotation axis is 45 degrees.

5. The bicycle bottom bracket according to claim 3, wherein: It also includes a second magnetic field sensor, wherein the torque reaction sleeve has a second permanent magnet magnetoelastic zone surrounding the rotating axis, the second permanent magnet magnetoelastic zone is distributed on a second reference plane, the second reference plane is not perpendicular to the rotating axis and is not parallel to the first reference plane, the second magnetic field sensor is arranged corresponding to the second permanent magnet magnetoelastic zone, and the second magnetic field sensor senses the magnetic field of the second permanent magnet magnetoelastic zone.

6. The bicycle bottom bracket according to claim 5, wherein: The first reference plane is perpendicular to the second reference plane.

7. The bicycle bottom bracket according to claim 5, wherein: The magnetic field of the first permanent magnet magnetoelastic region is in the same direction or in the opposite direction as the magnetic field of the second permanent magnet magnetoelastic region.

8. The bicycle bottom bracket according to claim 1, wherein: The first magnetic field sensor includes an induction coil, an inductor, a Hall element or a magnetoresistive element.

9. The bicycle bottom bracket according to claim 1, wherein: Also includes: A magnetic ring, wherein the magnetic ring is fixed around the main shaft and has a protrusion, and the protrusion is parallel to the rotation axis; a third magnetic field sensor, the third magnetic field sensor being disposed corresponding to the magnetic ring and sensing the magnetic field of the magnetic ring; as well as, A fourth magnetic field sensor is provided corresponding to the protrusion and senses a magnetic field of the protrusion.

10. The bicycle bottom bracket according to claim 1, wherein: The torque reaction sleeve comprises a sleeve body, and the first permanent magnet magnetoelastic region is fixed on the sleeve body; wherein the sleeve body is non-magnetic.

11. The bicycle bottom bracket according to claim 1, wherein: The system further comprises a fifth magnetic field sensor, which is arranged corresponding to the magnetoelastic region of the first permanent magnet and senses the magnetic field of the magnetoelastic region of the first permanent magnet.

12. The bicycle bottom bracket according to claim 1, wherein: The shear modulus of the torque reaction sleeve is smaller than the shear modulus of the main shaft and the transmission sleeve.

Images