Wheel drive mechanism and electrically assisted bicycle

Abstract

This disclosure provides a wheel power mechanism and an electric-assisted bicycle. The wheel power mechanism includes a central shaft, a freehub, an axial clutch structure, and a hub housing. The freehub is fitted onto one end of the central shaft. The axial clutch structure includes a first axial ratchet and a second axial ratchet. The first axial ratchet is movably fitted onto the central shaft along its axis and rotates in conjunction with the freehub, and includes a plurality of first teeth. The second axial ratchet is fitted onto the central shaft and includes a plurality of second teeth corresponding to the first teeth. The hub housing is fitted onto the central shaft and rotates in conjunction with the second axial ratchet. The first and second teeth engage; when the hub rotation speed of the hub housing is greater than the freehub rotation speed, the first and second teeth disengage, causing the first and second axial ratchets to disengage. This improves the stability of the wheel power mechanism.

Description

Technical Field

[0001] This disclosure relates to a power mechanism and a bicycle, and more particularly to a wheel power mechanism and an electric-assisted bicycle. Background Technology

[0002] In recent years, with the rise of environmental protection and sports, the usage rate of bicycles has increased significantly. However, bicycles are generally propelled by human pedaling, which can make it difficult for users to keep up with their physical strength on uphill sections.

[0003] Accordingly, some manufacturers have developed electric-assist bicycles, which can be equipped with a wheel power mechanism including a motor to provide assistance when the user pedals, thereby reducing the burden on the user. The wheel power mechanism may include a hub housing, a motor, a freehub, and a clutch. In one drive mode, the motor drives the clutch to rotate the hub housing; in another drive mode, the freehub drives the hub housing to rotate, and the freehub and hub housing include an axial clutch structure that can engage and disengage when their speeds differ.

[0004] However, conventional axial clutch structures, which include pawls, are susceptible to eccentricity, leading to unstable engagement between the freehub base and the hub housing. Therefore, there is still room for improvement. Utility Model Content

[0005] To address the aforementioned issues, this disclosure provides a wheel power mechanism and an electric-assisted bicycle, which, through structural configuration, enhances the stability of the engagement between the freehub base and the hub housing.

[0006] According to one embodiment of this disclosure, a wheel power mechanism is provided, comprising a central shaft, a freehub, an axial clutch structure, and a hub housing. The central shaft has an axis. The freehub is sleeved on one end of the central shaft. The axial clutch structure includes a first axial ratchet and a second axial ratchet. The first axial ratchet is movably sleeved on the central shaft along the axis and rotates in conjunction with the freehub, and the first axial ratchet includes a plurality of first teeth. The second axial ratchet is sleeved on the central shaft and includes a plurality of second teeth corresponding to the plurality of first teeth. The hub housing is sleeved on the central shaft and rotates in conjunction with the second axial ratchet. The plurality of first teeth and the plurality of second teeth engage, and a rotational force is transmitted to the hub housing via the freehub, the first axial ratchet, and the second axial ratchet, causing the hub housing to rotate. When the rotational speed of the hub housing is greater than the rotational speed of the freehub, the plurality of first teeth and the plurality of second teeth disengage, causing the first axial ratchet and the second axial ratchet to disengage.

[0007] The wheel power mechanism according to the aforementioned embodiment may further include a motor rotor and a clutch. The motor rotor is sleeved on the central shaft and located inside the hub housing. The clutch connects the motor rotor and the hub housing. A power source from the motor rotor is transmitted to the hub housing via the clutch, causing the hub housing to rotate.

[0008] According to the wheel power mechanism of the aforementioned embodiment, the freehub base may include a freehub base cylindrical portion, a freehub base bearing, and multiple recesses. The freehub base cylindrical portion surrounds a central shaft. The freehub base bearing is sleeved on the central shaft and located within the freehub base cylindrical portion. The aforementioned multiple recesses are disposed at one end of the freehub base cylindrical portion. The first axial ratchet includes multiple first radial protrusions that engage with the aforementioned multiple recesses. The axial clutch structure further includes an elastic element, which is sleeved on the central shaft and located within the freehub base cylindrical portion, and abuts against the first axial ratchet and the freehub base bearing.

[0009] According to the wheel power mechanism of the aforementioned embodiment, the length of a recess in each recess may be greater than the length of a tooth in each first radial tooth. When the first axial ratchet is pushed towards the base bearing by the second axial ratchet, each first radial tooth slides in each recess.

[0010] The wheel power mechanism according to the aforementioned embodiment may further include a connecting ring, which is sleeved on the central shaft and locked to the hub housing. The connecting ring includes multiple grooves, and a second axial ratchet is located inside the connecting ring and includes multiple second radial protrusions that engage with the aforementioned multiple grooves.

[0011] According to another embodiment of this disclosure, an electric-assisted bicycle is provided, comprising a frame and two wheels. The two wheels are disposed on the frame, and one of the wheels includes a wheel power mechanism of the aforementioned embodiment.

[0012] The electric-assisted bicycle according to the aforementioned embodiment may further include a motor rotor and a clutch. The motor rotor is sleeved on a central shaft and located inside the hub housing. The clutch connects the motor rotor and the hub housing. A power source from the motor rotor is transmitted to the hub housing via the clutch, causing the hub housing to rotate.

[0013] According to the aforementioned embodiment of the electric-assisted bicycle, the freehub base may include a freehub base cylindrical portion, a freehub base bearing, and a plurality of recesses. The freehub base cylindrical portion surrounds a central axis. The freehub base bearing is sleeved on the central axis and located within the freehub base cylindrical portion. The plurality of recesses are disposed at one end of the freehub base cylindrical portion. The first axial ratchet includes a plurality of first radial protrusions that engage with the plurality of recesses. The axial clutch structure further includes an elastic element, which is sleeved on the central axis and located within the freehub base cylindrical portion, and abuts against the first axial ratchet and the freehub base bearing.

[0014] According to the electric-assisted bicycle of the aforementioned embodiment, the length of a recess in each recess may be greater than the length of a tooth in each first radial tooth, and when the first axial ratchet is pushed towards the base bearing by the second axial ratchet, each first radial tooth slides in each recess.

[0015] The electric-assisted bicycle according to the aforementioned embodiment may further include a connecting ring, which is sleeved on the central shaft and locked to the hub housing. The connecting ring includes multiple grooves, and a second axial ratchet is located inside the connecting ring and includes multiple second radial protrusions that engage with the aforementioned multiple grooves. Attached Figure Description

[0016] Figure 1 A perspective view of a wheel power mechanism according to an embodiment of the present disclosure is shown;

[0017] Figure 2 Draw Figure 1 An exploded view of the wheel power mechanism in the embodiment;

[0018] Figure 3 Draw Figure 1 A partial cross-sectional schematic view of the wheel power mechanism in the embodiment;

[0019] Figure 4 Draw Figure 1 Another cross-sectional schematic diagram of the wheel power mechanism in the embodiment; and

[0020] Figure 5 A side view schematic diagram of an electric-assisted bicycle according to another embodiment of the present disclosure is shown.

[0021] [Symbol Explanation]

[0022] 100,231: Wheel power mechanism

[0023] 110: Central axis

[0024] 120: Tower Base

[0025] 121: Tower base cylindrical section

[0026] 122: Tower base bearing

[0027] 123: concave part

[0028] 130: Axial clutch structure

[0029] 131: First Axial Ratchet

[0030] 1311: First facet tooth

[0031] 1312: First radial protrusion

[0032] 132: Second Axial Ratchet

[0033] 1321: Second facet tooth

[0034] 1322: Second radial protrusion

[0035] 133: Elastic component

[0036] 140: Hub shell

[0037] 141: End plate

[0038] 150: Protrusion

[0039] 160: Connecting ring

[0040] 161: Ditch

[0041] 170: Clutch

[0042] 180: Motor

[0043] 191, 192: Fixed sleeve

[0044] 200: Electric-assisted bicycle

[0045] 210: Chassis

[0046] 220, 230: Wheels

[0047] D1: concave length

[0048] D2: Length of the protrusion tooth

[0049] X1: Axis Detailed Implementation

[0050] The embodiments of this disclosure will now be described with reference to the accompanying drawings. For clarity, many practical details will be set forth in the following description. However, the reader should understand that these practical details should not be used to limit this disclosure. That is, in some embodiments of this disclosure, these practical details are not essential. Furthermore, for the sake of simplicity in the drawings, some conventional structures and elements will be shown in a simple schematic manner; and repeated elements may be denoted by the same or similar designations.

[0051] Furthermore, the terms "first," "second," and "third" used in this article are merely used to describe different components or parts, and do not impose any restrictions on the components / parts themselves. Therefore, the first component / part can also be referred to as the second component / part. Moreover, the combinations of components / parts / mechanisms / modules in this article are not combinations generally known, conventional, or customary in this field. Whether the components / parts / mechanisms / modules themselves are customary cannot be used to determine whether their combination relationships are easily accomplished by someone with ordinary knowledge in the technical field.

[0052] Please see Figure 1 and Figure 2 , Figure 1 A perspective view of a wheel power mechanism 100 according to an embodiment of the present disclosure is shown. Figure 2 Draw Figure 1 An exploded view of the wheel power mechanism 100 of the embodiment. The wheel power mechanism 100 includes a central shaft 110, a hub base 120, an axial clutch structure 130, and a hub housing 140.

[0053] The central axis 110 has an axis X1 (shown in...) Figure 3 The freehub base 120 is fitted onto one end of the central shaft 110. The axial clutch structure 130 includes a first axial ratchet 131 and a second axial ratchet 132. The first axial ratchet 131 is movably fitted onto the central shaft 110 along axis X1 and is rotatably linked with the freehub base 120. The first axial ratchet 131 includes a plurality of first face teeth 1311. The second axial ratchet 132 is fitted onto the central shaft 110 and includes a plurality of second face teeth 1321 corresponding to the aforementioned plurality of first face teeth 1311. The hub housing 140 is fitted onto the central shaft 110 and is rotatably linked with the second axial ratchet 132. In this configuration, the aforementioned plurality of first face teeth 1311 mesh with the aforementioned plurality of second face teeth 1321. A rotational force is transmitted to the hub housing 140 via the freehub base 120, the first axial ratchet 131, and the second axial ratchet 132, causing the hub housing 140 to rotate. When the rotational speed of one hub of the hub housing 140 is greater than the rotational speed of one freehub base 120, the aforementioned plurality of first face teeth 1311 and the aforementioned plurality of second face teeth 1321 disengage from each other, so that the first axial ratchet 131 and the second axial ratchet 132 are not connected.

[0054] In this way, the engagement of the first tooth 1311 and the second tooth 1321 can avoid the problem of unstable meshing caused by eccentricity, and the larger contact area can reduce stress concentration, thereby improving the stability and service life of the wheel power mechanism 100.

[0055] The central shaft 110 can be a hollow rod structure or a solid rod structure. The wheel power mechanism 100 may further include two fixed sleeves 191 and 192, which are respectively sleeved on the two ends of the central shaft 110. The fixed sleeves 191 and 192 can respectively power an electric-assisted bicycle (such as...) Figure 5 The two fixed parts of the rear fork of the electric-assisted bicycle 200 are fixed thereon. When needed, the central shaft 110 can be pulled out along the axis X1, so that the fixed sleeves 191 and 192 can drive the rear fork to be separated from other components of the wheel power mechanism 100, thereby achieving the effect of convenient maintenance or replacement.

[0056] Please see Figure 3 and Figure 4 See also Figure 2 , Figure 3 Draw Figure 1 A partial cross-sectional schematic diagram of the wheel power mechanism 100 in the embodiment. Figure 4 Draw Figure 1 Another cross-sectional view of the wheel power mechanism 100 of the embodiment. The hub housing 140 is a hollow cylinder connected to spokes, which can be connected to a steel rim, and a tire can be mounted on the steel rim. The wheel power mechanism 100 may also include a connecting ring 160 and a protrusion 150. The connecting ring 160 is sleeved on the central shaft 110 and located inside the hub housing 140, and is locked to the end plate 141 of the hub housing 140 facing the freehub base 120. The connecting ring 160 is annular and includes a shaft hole and multiple grooves 161. The shaft hole allows the central shaft 110 to pass through it, and the grooves 161 can be arranged around the hole wall of the shaft hole. The protrusion 150 can be sleeved on the central shaft 110 and protrude from the shaft hole.

[0057] The freehub base 120 is located along axis X1 between the aforementioned end plate 141 and a fixing part of the hub housing 140, and the freehub base 120 is rotated by a chain. Specifically, the freehub base 120 may include a freehub base cylindrical portion 121, a freehub base bearing 122, and a plurality of recesses 123. The freehub base cylindrical portion 121 may surround a central shaft 110. The freehub base bearing 122 is sleeved on the central shaft 110 and located within the freehub base cylindrical portion 121. The aforementioned plurality of recesses 123 are provided at one end of the freehub base cylindrical portion 121.

[0058] like Figure 3 As shown, the protrusion 150 is located between the inner circumferential surface of the tower base cylinder 121 and the outer circumferential surface of the central shaft 110. The number of tower base bearings 122 can be two, arranged at intervals within the tower base cylinder 121 to support the tower base cylinder 121. The recess 123 is adjacent to the end plate 141 above the tower base bearings 122. Each recess 123 is a groove-shaped structure formed by reducing the radial thickness of the tower base cylinder 121.

[0059] The first axial ratchet 131 may be accommodated within the tower base cylindrical portion 121 and adjacent to the end plate 141, and the first axial ratchet 131 may include a plurality of first radial protrusions 1312 that engage with the aforementioned plurality of recesses 123. Specifically, the first axial ratchet 131 may include a first annular body (not shown), the first face teeth 1311 may be located on a surface of the first annular body facing the end plate 141, and the first radial protrusions 1312 may be located on the outer peripheral surface of the first annular body. Therefore, the first radial protrusions 1312 may protrude into the recesses 123 and engage with the recesses 123 and rotate in conjunction with the tower base 120.

[0060] Furthermore, the length D1 of each recess 123 can be greater than the length D2 of each first radial tooth 1312. Therefore, when the first axial ratchet 131 is pushed towards the base bearing 122 by the second axial ratchet 132, each first radial tooth 1312 can slide within each recess 123. Specifically, the first axial ratchet 131 is movably housed in the base cylindrical portion 121 and rotates in conjunction with the engagement of the first radial tooth 1312 with the recess 123. The first axial ratchet 131 can be pushed and moved along the axis X1 between an engaged position and a disengaged position. Therefore, by configuring the recess length D1 to be greater than the tooth length D2, the first axial ratchet 131 can be guided to move relative to the base 120, and regardless of whether the first axial ratchet 131 is in the engaged or disengaged position, it can rotate in conjunction with the base 120.

[0061] The second axial ratchet 132 is located within the connecting ring 160 and has a structure similar to the first axial ratchet 131. Therefore, the second axial ratchet 132 includes a second annular body (not shown) and a plurality of second radial protrusions 1322. The second surface teeth 1321 may be located on a surface of the second annular body facing the first axial ratchet 131, and the second radial protrusions 1322 may be located on the outer peripheral surface of the second annular body. Specifically, the second axial ratchet 132 may be located within the shaft hole of the connecting ring 160, so the second radial protrusions 1322 may protrude into the groove 161 and engage with the groove 161, thereby limiting the second axial ratchet 132 with the connecting ring 160 and indirectly limiting it with the hub housing 140.

[0062] The axial clutch structure 130 may further include an elastic element 133, which is sleeved on the central shaft 110 and located inside the tower base cylindrical portion 121. The elastic element 133 abuts against the first axial ratchet 131 and the tower base bearing 122. That is, the elastic element 133 can push the first axial ratchet 131 toward the second axial ratchet 132, so that the first axial ratchet 131 and the second axial ratchet 132 engage.

[0063] The wheel power mechanism 100 may further include a motor rotor (not shown) and a clutch 170. The motor rotor is mounted on the central shaft 110 and located inside the hub housing 140. The clutch 170 connects the motor rotor and the hub housing 140. Power from the motor rotor is transmitted to the hub housing 140 via the clutch 170, causing the hub housing 140 to rotate. More specifically, the wheel power mechanism 100 may include a motor 180 mounted on the central shaft 110. The motor 180 may include a motor rotor, a motor stator, and a reduction gear set. The reduction gear set connects the motor rotor and the clutch 170. Thus, when the motor stator is energized, the motor rotor rotates, which in turn drives the reduction gear set and drives the hub housing 140. In this embodiment, the clutch 170 may include a rolling outer ring, a rolling inner ring, and multiple rollers, needle rollers, or balls. Through its shape configuration, the rolling outer ring can only rotate relative to the rolling inner ring in a single direction, so the motor rotor and the hub housing 140 can only rotate in a single direction. Since the structure of the motor 180 and clutch 170 is not the focus of this disclosure, its details will not be elaborated here, and the accompanying drawings also simplify the structure of the motor 180 and clutch 170, and are not intended to limit this disclosure. In other embodiments, the clutch may also connect the motor rotor and the hub end plate.

[0064] like Figure 3 As shown, at this time, the first axial ratchet 131 is in the engaged position and engages with the second axial ratchet 132. The user can step on the pedal to drive the freehub base 120, which in turn drives the connecting ring 160 and the hub housing 140 to rotate. A pedaling sensor or a torque sensor can be further installed on the bicycle to sense the pedal being pressed and the force applied by the user, thereby driving the motor 180 to provide corresponding assistance. Figure 4 As shown, when the hub speed of the hub shell 140 is greater than the freehub speed of the freehub base 120, the first axial ratchet 131 can be moved to the disengaged position, so that the first tooth 1311 and the second tooth 1321 disengage from each other. In this way, even if the increased assistance causes the hub speed of the hub shell 140 to be too fast, it will not affect the user's ability to pedal and drive the freehub base 120.

[0065] Please see Figure 5 , Figure 5 A side view schematic diagram of an electric-assisted bicycle 200 according to another embodiment of the present disclosure is shown. The electric-assisted bicycle 200 may include a frame 210 and two wheels 220, 230. The two wheels 220, 230 are disposed on the frame 210, and the wheel 230 includes a wheel power mechanism 231. The structure of the wheel power mechanism 231 may be similar to... Figures 1 to 4 The wheel power mechanism is the same as 100, and the details will not be repeated.

[0066] Although this disclosure has been presented above with reference to embodiments, it is not intended to limit this disclosure. Any person skilled in the art may make various modifications and refinements without departing from the spirit and scope of this disclosure. Therefore, the scope of protection of this disclosure shall be determined by the appended claims.

Claims

1. A wheel power mechanism, characterized in that, Include: A central axis, possessing an axis; A tower base is fitted onto one end of the central axis; A uniaxial clutch structure, comprising: A first axial ratchet, movably fitted onto the central shaft along the axis and rotatably linked to the tower base, the first axial ratchet comprising a plurality of first face teeth; and A second axial ratchet, fitted onto the central shaft and comprising a plurality of second face teeth corresponding to the first face teeth; and A hub shell is fitted onto the central shaft and rotates in conjunction with the second axial ratchet. Wherein, the first face tooth and the second face tooth mesh, and a rotational force is transmitted to the hub shell through the freehub base, the first axial ratchet, and the second axial ratchet, causing the hub shell to rotate. When the rotational speed of the hub shell is greater than the rotational speed of the freehub base, the first face tooth and the second face tooth disengage from each other, so that the first axial ratchet and the second axial ratchet are not connected.

2. The wheel power mechanism as described in claim 1, characterized in that, Also includes: An electric motor rotor, fitted onto the central shaft and located within the hub housing; and A clutch connects the motor rotor to the hub housing; In this process, the power of the motor rotor is transmitted to the hub housing via the clutch, causing the hub housing to rotate.

3. The wheel power mechanism as described in claim 1, characterized in that, The tower base includes: The base of the tower, surrounding the central axis; A tower base bearing, fitted onto the central shaft and located within the tower base cylindrical section; and Multiple recesses are provided at one end of the tower base cylindrical section; The first axial ratchet includes a plurality of first radial protrusions that engage with the recess. The axial clutch structure also includes an elastic element, which is sleeved on the central shaft and located inside the tower base cylinder. The elastic element abuts against the first axial ratchet and the tower base bearing.

4. The wheel power mechanism as described in claim 3, characterized in that, The length of one recess of each of the recesses is greater than the length of one tooth of each of the first radial teeth. When the first axial ratchet is pushed towards the tower base bearing by the second axial ratchet, each of the first radial teeth slides within each of the recesses.

5. The wheel power mechanism as described in claim 1, characterized in that, It also includes a connecting ring, which is sleeved on the central shaft and locked to the hub housing. The connecting ring includes multiple grooves, and the second axial ratchet is located inside the connecting ring and includes multiple second radial protrusions that engage with the grooves.

6. An electric-assisted bicycle, characterized in that, Include: A frame; and Two wheels are mounted on the frame, and one of the wheels includes a wheel power mechanism as described in claim 1.

7. The electric-assisted bicycle as described in claim 6, characterized in that, Also includes: An electric motor rotor, fitted onto the central shaft and located within the hub housing; and A clutch connects the motor rotor to the hub housing; In this process, the power of the motor rotor is transmitted to the hub housing via the clutch, causing the hub housing to rotate.

8. The electric-assisted bicycle as described in claim 7, characterized in that, The tower base includes: The base of the tower, surrounding the central axis; A tower base bearing, fitted onto the central shaft and located within the tower base cylindrical section; and Multiple recesses are provided at one end of the tower base cylindrical section; The first axial ratchet includes a plurality of first radial protrusions that engage with the recess. The axial clutch structure also includes an elastic element, which is sleeved on the central shaft and located inside the tower base cylinder. The elastic element abuts against the first axial ratchet and the tower base bearing.

9. The electric-assisted bicycle as described in claim 8, characterized in that, The length of one recess of each of the recesses is greater than the length of one tooth of each of the first radial teeth. When the first axial ratchet is pushed towards the tower base bearing by the second axial ratchet, each of the first radial teeth slides within each of the recesses.

10. The electric-assisted bicycle as described in claim 6, characterized in that, It also includes a connecting ring, which is sleeved on the central shaft and locked to the hub housing. The connecting ring includes multiple grooves, and the second axial ratchet is located inside the connecting ring and includes multiple second radial protrusions that engage with the grooves.

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