A hub structure for an electric bicycle hub motor

Abstract

The utility model discloses a hub structure for an electric bicycle hub motor, wherein the hub motor comprises a stator and a rotor, wherein the rotor comprises a magnetic steel and a rotor winding, wherein the hub comprises a rim for mounting a tire and a magnetic yoke for mounting a rotor, wherein the rim is an annular plate, wherein the magnetic yoke is cylindrical, wherein the magnetic yoke is placed in the inner cavity of the rim, and wherein the outer wall of the magnetic yoke is fixedly connected to the inner wall of the rim so that the two form an integral part, wherein an annular groove is provided on the inner cavity wall surface of the magnetic yoke, and a plurality of through holes evenly distributed along the circumferential direction are respectively provided on the end surfaces at both ends of the magnetic yoke, wherein the magnetic steel in the rotor is fixedly installed in the annular groove of the magnetic yoke. The utility model improves the power density of the hub motor, increases the torque of the hub motor, reduces the weight of the motor, and reduces the production cost.

Description

Technical Field

[0001] The utility model relates to an electric bicycle, in particular to a wheel hub for installing a wheel hub motor and a tire of the electric bicycle, and belongs to the technical field of electric bicycles. Background Art

[0002] The existing hub structure for the hub motor of an electric bicycle comprises a stator and a rotor, the rotor comprises a magnetic steel and a rotor winding, the hub comprises a rim for mounting a tire and a yoke for mounting the rotor, the rim is an annular plate, the yoke is cylindrical, the yoke is placed in the inner cavity of the rim, and the outer wall of the yoke is fixedly connected to the inner wall of the rim, so that the two form an integral part, and the magnetic steel in the rotor is fixedly mounted on the inner cavity wall of the yoke.

[0003] However, the wheel hub of the hub motor with this structure has the following two disadvantages in actual use: on the one hand, due to the thick wall thickness of the yoke, the weight of the hub motor is heavy, which not only increases the installation and maintenance intensity, but also increases the overall weight and production cost of the electric bicycle; on the other hand, with this hub structure, the power density of the hub motor is low and the torque is small. Summary of the invention

[0004] The technical problem to be solved by the utility model is to overcome the deficiencies of the prior art and provide a hub structure for an electric bicycle hub motor which can improve the power density of the hub motor, increase the torque of the hub motor, reduce the weight of the motor and reduce the production cost.

[0005] In order to solve the above technical problems, the utility model adopts a hub structure for an electric bicycle hub motor, wherein the hub motor includes a stator and a rotor, the rotor includes a magnetic steel and a rotor winding, the hub includes a rim for mounting a tire and a yoke for mounting a rotor, the rim is an annular plate, the yoke is cylindrical, the yoke is placed in the inner cavity of the rim, and the outer wall of the yoke is fixedly connected to the inner wall of the rim so that the two form an integral part, an annular groove is provided on the inner cavity wall surface of the yoke, and a plurality of through holes evenly distributed in the circumferential direction are respectively provided on the end surfaces of both ends of the yoke, and the magnetic steel in the rotor is fixedly installed in the annular groove of the yoke.

[0006] As a preferred embodiment of the present invention, the magnetic steel in the rotor is fixedly installed in the annular groove of the yoke by adhesive, and the outer wall of the yoke is fixedly connected to the inner wall of the rim by welding.

[0007] As a preferred embodiment of the present utility model, the annular groove is a circular annular groove with a circular ring shape in cross section or a trapezoidal annular groove with a trapezoidal cross section.

[0008] After adopting the above structure, the utility model has the following beneficial effects:

[0009] Since the power density and torque of the wheel hub motor are proportional to d 2 ×L, d is the rotor diameter, L is the rotor length, that is, the power density and torque are proportional to the square of the rotor diameter. Therefore, as long as the rotor diameter d is increased, the square of the rotor diameter d will increase greatly, thereby greatly improving the power density and torque of the hub motor. The utility model provides an annular groove on the inner cavity wall of the yoke, so that the yoke can be installed to accommodate a rotor with a larger diameter. That is to say, the utility model increases the rotor diameter by providing an annular groove on the inner cavity wall of the yoke. Based on the fact that the power density and torque are proportional to the square of the rotor diameter, the power density of the hub motor is greatly improved and the torque is increased. Moreover, since an annular groove is provided on the inner cavity wall of the yoke, the weight of the yoke and the motor is reduced, and the production cost is also reduced.

[0010] The utility model opens an annular groove on the inner cavity wall surface of the magnetic yoke, so that the thickness of both ends of the magnetic yoke is thinner, so it is more convenient to process the through hole on the end surface, and the processing difficulty is reduced.

[0011] The utility model has a simple structure and is easy to implement, reduces the installation and maintenance intensity of the hub motor, and reduces the weight of the entire electric bicycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The specific implementation of the utility model is further described in detail below in conjunction with the accompanying drawings.

[0013] Figure 1 The utility model is a schematic structural diagram of a hub structure for an electric bicycle hub motor.

[0014] Figure 2 for Figure 1 Schematic diagram of the main view.

[0015] Figure 3 for Figure 2 Schematic cross-sectional view along line A-A. DETAILED DESCRIPTION

[0016] See also Figures 1 to 3A hub structure for an electric bicycle hub motor is shown, the hub motor includes a stator and a rotor, the rotor includes a magnetic steel and a rotor winding, the hub includes a rim 1 for mounting a tire and a yoke 2 for mounting a rotor, the rim 1 is an annular plate, usually formed by stamping or rolling a steel plate, the yoke 2 is cylindrical, usually a cylindrical steel part, the yoke 2 is placed in the inner cavity of the rim 1, and the outer wall of the yoke 2 is fixedly connected to the inner wall of the rim 1 so that the two form an integral part, an annular groove 2-1 is provided on the inner cavity wall surface of the yoke 2, and a plurality of through holes 3 evenly distributed in the circumferential direction are respectively provided on the end surfaces of both ends of the yoke 2, the through holes 3 are mainly used for installing components in the rotor, and the magnetic steel in the rotor is fixedly installed in the annular groove 2-1 of the yoke 2, and the tire and the magnetic steel are not shown in the figure.

[0017] As a preferred embodiment of the utility model, the magnetic steel in the rotor is fixedly installed in the annular groove 2-1 of the yoke 2 by adhesive, and the outer wall of the yoke 2 is fixedly connected to the inner wall of the rim 1 by welding.

[0018] As a preferred embodiment of the present invention, the annular groove 2-1 is an annular groove with a circular ring shape in cross section or a trapezoidal annular groove with a trapezoidal cross section. The figure only shows the annular groove, and does not show the trapezoidal annular groove.

[0019] After trial use, the utility model improves the power density of the hub motor, increases the torque of the hub motor, reduces the weight of the motor, reduces the production cost, and achieves good practical effects.

Claims

1. A hub structure for an electric bicycle hub motor, the hub motor comprising a stator and a rotor, the rotor comprising a magnetic steel and a rotor winding, the hub comprising a rim (1) for mounting a tire and a yoke (2) for mounting the rotor, the rim (1) being an annular plate, the yoke (2) being cylindrical, the yoke (2) being disposed in an inner cavity of the rim (1), and the outer wall of the yoke (2) being fixedly connected to the inner wall of the rim (1) so that the two form an integral part, characterized in that: An annular groove (2-1) is provided on the inner cavity wall surface of the magnetic yoke (2), and a plurality of through holes (3) evenly distributed along the circumferential direction are respectively provided on the end surfaces at both ends of the magnetic yoke (2). The magnetic steel in the rotor is fixedly mounted in the annular groove (2-1) of the magnetic yoke (2).

2. The hub structure for an electric bicycle hub motor according to claim 1, characterized in that: The magnetic steel in the rotor is fixedly mounted in the annular groove (2-1) of the yoke (2) by means of an adhesive, and the outer wall of the yoke (2) is fixedly connected to the inner wall of the rim (1) by means of welding.

3. The hub structure for an electric bicycle hub motor according to claim 1 or 2, characterized in that: The annular groove (2-1) is a circular annular groove with a circular annular cross section or a trapezoidal annular groove with a trapezoidal cross section.

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