Multi-disc hub motor

Abstract

The utility model relates to a multi-disc type hub motor. The multi-disc type hub motor comprises a middle shaft, a shell assembly and a stator and rotor assembly, wherein the middle shaft is fixedly arranged; the shell assembly comprises a box body and a cover plate, the box body and the cover plate are combined to form a closed internal space, and the stator and rotor assembly is arranged in the internal space; the stator and rotor assembly comprises a plurality of stators and a plurality of rotors which are arranged at intervals, the stators are fixedly connected with the middle shaft, the rotors are fixedly connected with the shell assembly, each stator is located between every two adjacent rotors to form an axial magnetic flux path, and the number of the rotors is one more than that of the stators. In a limited internal space, a plurality of stators and a plurality of rotors can be arranged, and larger torque is provided.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electrically assisted bicycles, in particular to a multi-disc hub motor. BACKGROUND

[0002] European patent EP2921397B1 discloses a hub motor of an electric bicycle, which includes an inner stator, an outer rotor, a reduction gear, etc. At present, the hub motor as described above is widely used in the field of electrically assisted bicycles. However, the output of auxiliary power of such electrically assisted bicycles is limited when climbing uphill, and the rider still needs to pedal hard when riding uphill. SUMMARY

[0003] In order to improve the output torque of the motor, the present application provides a multi-disc hub motor.

[0004] The multi-disc hub motor provided by the present application adopts the following technical solutions:

[0005] A multi-disc hub motor, comprising a middle shaft, a housing assembly and a stator-rotor assembly; wherein the middle shaft is fixedly arranged; the housing assembly comprises a box body and a cover plate, and the box body and the cover plate combine to form a closed internal space, and the stator-rotor assembly is arranged in the internal space; the stator-rotor assembly comprises a plurality of stators and a plurality of rotors arranged at intervals along the axial direction, the plurality of stators are fixedly connected with the middle shaft, the plurality of rotors are fixedly connected with the housing assembly, a single stator is located between two adjacent rotors to form an axial magnetic flux path, and the number of rotors is one more than the number of stators.

[0006] Optionally, the stator is a printed circuit board stator, comprising a substrate; a plurality of groups of windings are etched on the substrate, and the plurality of groups of windings are arranged in rotational symmetry about the central axis of the substrate.

[0007] Optionally, one of the rotors is integrated with the cover plate, the rotor comprises a plurality of permanent magnets, the plurality of permanent magnets are arranged in rotational symmetry about the central axis of the cover plate, and the permanent magnets are fixedly connected to the cover plate directly or indirectly.

[0008] Optionally, the rotor comprises a rotor disc and a plurality of permanent magnets, the plurality of permanent magnets are arranged in rotational symmetry about the central axis of the cover plate, and the rotor disc is provided with a mounting groove for mounting the permanent magnets on the end face, and the mounting groove does not penetrate the rotor disc.

[0009] Optionally, the rotor comprises two rotor discs and a plurality of permanent magnets, the plurality of permanent magnets are arranged rotationally symmetrically about the center axis of the cover plate, the rotor disc end face is provided with an installation slot for installing the permanent magnet, and the installation slot penetrates the rotor disc; the two rotor discs are provided with an outer blocking ring and an inner blocking ring on the side facing away from each other, the outer blocking ring partially shields the radial one end of the installation slot, and the inner blocking ring partially shields the radial other end of the installation slot.

[0010] Optionally, the box comprises an end plate, a side plate and two flanges fixedly connected with each other; the cover plate comprises an end plate and an inner edge fixedly connected with each other; the end plate is used for shielding the end face of the whole motor, the side plate is used for shielding the circumferential side face of the whole motor, the two flanges protrude from the outer surface of the side plate and are used for providing limiting for the hub, and the inner edge protrudes from the inner end face of the cover plate and is used for abutting with the inner circumferential side of the side plate.

[0011] Optionally, the stator is fixedly connected with the middle shaft through a stepped fixing piece, the stepped fixing piece is directly or indirectly in interference fit with the middle shaft, and the stepped fixing piece has a plurality of bosses with different outer diameters; in the direction towards the cover plate, the inner diameters of the plurality of stators gradually decrease, and the outer diameters of the plurality of bosses gradually decrease.

[0012] Optionally, the rotor is fixedly connected with the box through a fixing ring, the box and the fixing ring are directly or indirectly fixedly connected, in the direction towards the cover plate, the inner diameters of the plurality of fixing rings gradually increase, and the outer diameters of the plurality of rotors gradually increase.

[0013] The stator-rotor assembly forms an axial magnetic flux path, reduces the axial length of the stator and the rotor, a plurality of stators and rotors can be arranged in the limited internal space, thereby providing greater torque, so that the rider is more labor-saving in the climbing state, and the cycling experience is improved. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 It is a whole structure schematic diagram of a multi-disc wheel hub motor in the embodiment of the application.

[0015] Figure 2 It is a structure sectional view of a multi-disc wheel hub motor in the embodiment of the application.

[0016] Figure 3 It is a whole structure schematic diagram of a box in a multi-disc wheel hub motor in the embodiment of the application.

[0017] Figure 4 It is a structure schematic diagram of a cover plate in a multi-disc wheel hub motor in the embodiment of the application.

[0018] Figure 5 It is a structure schematic diagram of a stator in a multi-disc wheel hub motor in the embodiment of the application.

[0019] Figure 6 is a schematic diagram of different structures of stator windings in a multi-disc wheel hub motor in an embodiment of the present application.

[0020] Figure 7 is a schematic diagram of the structure of a rotor in a multi-disc wheel hub motor in an embodiment of the present application.

[0021] Figure 8 is another schematic diagram of the structure of a rotor in a multi-disc wheel hub motor in an embodiment of the present application.

[0022] Figure 9 is Figure 2 is a structure enlarged view of part A in

[0023] Reference signs: 100, central shaft; 200, housing assembly; 210, box body; 211, first end plate; 212, side plate; 213, first flange; 214, second flange; 215, first boss; 220, cover plate; 221, second end plate; 222, inner edge; 223, second boss; 300, stator-rotor assembly; 310, stator; 311, PCB substrate; 312, winding; 320, rotor; 321, rotor disc; 322, permanent magnet; 323, outer retaining ring; 324, inner retaining ring; 330, stepped fixing member; 341, first fixing ring; 342, second fixing ring. DETAILED DESCRIPTION

[0024] The following will be described in detail below with reference to the accompanying drawings. Figures 1-9 The present application will be further described in detail.

[0025] An embodiment of the present application discloses a multi-disc wheel hub motor.

[0026] With reference to Figure 1 A multi-disc wheel hub motor includes a central shaft 100, a housing assembly 200, and a stator-rotor assembly 300; the overall motor is generally in a cylindrical structure. The central shaft 100 is fixedly installed on the electric-assisted bicycle frame, the housing assembly 200 is fixedly connected with the wheel hub of the electric-assisted bicycle, and the stator-rotor assembly 300 provides electric assistance for the overall motor.

[0027] With reference to Figure 2 and Figure 3The housing assembly 200 comprises a box 210 and a cover plate 220. The box 210 comprises a first end plate 211, a side plate 212, a first flange 213, a second flange 214 and a first boss 215. In the embodiment, the first end plate 211, the side plate 212, the first flange 213, the second flange 214 and the first boss 215 are integrally formed. The first end plate 211 is used to shield one end surface of the motor cylindrical structure. The side plate 212 is connected to the inner end surface of the first end plate 211 and is used to shield the circumferential surface of the motor cylindrical structure. The first flange 213 is enclosed around the outer periphery of the first end plate 211 and protrudes from the outer surface of the side plate 212. The second flange 214 is enclosed around the outer periphery of the side plate 212 away from the first end plate 211 and protrudes from the outer surface of the side plate 212. The first flange 213 and the second flange 214 are relatively parallel and protrude from the outer surface of the motor as a whole to provide a limit for the hub of the electric-assisted bicycle. The first boss 215 is coaxial with the motor cylindrical structure and is arranged at the center of the first end plate 211. The first boss 215 is hollow for the middle shaft 100 to pass through.

[0028] Referring to Figure 4 The cover plate 220 comprises a second end plate 221, an inner rim 222 and a second boss 223. In the embodiment, the second end plate 221, the inner rim 222 and the second boss 223 are integrally formed. The second end plate 221 is attached to the end of the side plate 212 away from the first end plate 211 and is used to shield the other end surface of the motor cylindrical structure. The inner rim 222 is annular and is arranged at the inner end surface of the second end plate 221. The outer peripheral side of the inner rim 222 is attached to the inner peripheral side of the side plate 212 to provide better airtightness for the motor as a whole and to provide positioning for the connection between the cover plate 220 and the box 210, thereby ensuring the relative position of the cover plate 220 and the box 210. The second boss 223 is coaxial with the motor cylindrical structure and is arranged at the center of the second end plate 221. The second boss 223 is hollow for the middle shaft 100 to pass through. The housing assembly 200 composed of the box 210 and the cover plate 220 encloses a closed internal space, and the rotor assembly 300 is installed in the internal space.

[0029] Referring to Figure 2The stator-rotor assembly 300 comprises a plurality of stators 310 and a plurality of rotors 320. The stators 310 and the rotors 320 are arranged along the axial direction of the motor, that is, one stator 310 is located between two adjacent rotors 320, and therefore, in terms of quantity, the number of rotors 320 is always one more than the number of stators 310. In the present application, the stators 310 and the rotors 320 are arranged along the axial direction of the motor, forming a magnetic flux path direction parallel to the axial direction of the motor and closed along the axial and circumferential directions, and the whole forms an internal magnetic field of a three-dimensional structure, which greatly reduces the axial length of the stator-rotor assembly 300 compared with the prior art. That is, in a limited internal space, a plurality of stators 310 and a plurality of rotors 320 can be arranged to increase the torque that can be output by the motor. In the present embodiment, there are two stators 310 and three rotors 320.

[0030] For the convenience of description, the stator-rotor assembly 300 is defined as having a first end and a second end along the axial direction, the first end being the end close to the inner end face of the box body 210, and the second end being the end close to the inner end face of the cover plate 220; the direction from the first end to the second end and the direction of the internal space of the housing assembly 200 towards the cover plate. In the present application, the first end and the second end of the stator-rotor assembly 300 are both rotors 320.

[0031] Referring to Figure 5 The stator 310 adopts a printed circuit board stator (PCB stator), that is, a plurality of groups of windings 312 are etched on the PCB substrate 311, and the plurality of groups of windings 312 are arranged rotationally symmetrically about the central axis of the PCB substrate 311. The shape of the winding 312 can be a combined winding, a circular winding, a trapezoidal winding or a rhombic winding, as shown in a-d of Figure 6 It should be noted that the positions, structures and numbers of the windings 312 shown in the drawings are only exemplary and do not limit the positions, structures and numbers of the windings protected in the present application.

[0032] The rotor 320 comprises a plurality of permanent magnets 322, and the plurality of permanent magnets 322 are arranged rotationally symmetrically about the central axis of the cover plate 220. The shape of the permanent magnet 322 can be circular, rectangular, etc. It should be noted that the positions, structures and numbers of the permanent magnets 322 shown in the drawings are only exemplary and do not limit the positions, structures and numbers of the permanent magnets protected in the present application, nor do they limit the pole-slot ratio of the stator-rotor assembly 300 protected in the present application. Referring to Figure 4 In the present embodiment, the rotor 320a at the second end is integrated with the cover plate 220, that is, the permanent magnet 322 is fixedly connected with the cover plate 220. Specifically, the permanent magnet 322 can be directly bonded to the inner surface of the cover plate 220 by glue; or a positioning groove for mounting the permanent magnet 322 can be formed in the inner surface of the cover plate 220, and the permanent magnet 322 is bonded in the positioning groove. The rotors 320 located between the first end and the second end can adopt the structure shown in Figure 7 or the structure shown in Figure 8 . Referring toFigure 7 The rotor 320b comprises a rotor disc 321b and permanent magnets 322. The rotor disc 321b is provided with installation grooves for installing the permanent magnets 322 on one end face, the installation grooves do not penetrate the rotor disc 321b, and the permanent magnets 322 are bonded in the installation grooves by glue. Refer to Figure 8 The rotor 320c comprises two oppositely arranged rotor discs 321c; the rotor disc 321c is provided with installation grooves for installing the permanent magnets 322, and the installation grooves penetrate the rotor disc 321c. The two rotor discs 321c are provided with outer retaining rings 323 and inner retaining rings 324 on the sides away from each other. The outer retaining rings 323 and the inner retaining rings 324 are integrally formed with the rotor disc 321c. The outer retaining ring 323 partially shields one end of the installation groove in the radial direction, and the inner retaining ring 324 partially shields the other end of the installation groove in the radial direction. During installation, the permanent magnet 322 is placed in the installation groove of one rotor disc 321c, and the outer retaining ring 323 and the inner retaining ring 324 prevent the permanent magnet 322 from falling out of the installation groove; after aligning the installation groove of the other rotor disc 321c with the permanent magnet 322, the two rotor discs 321c are fixedly connected to form a rotor 320c. The fixed connection of the two rotor discs 321 can be achieved by screws, bolts, gluing, etc.

[0033] The installation method of the stator-rotor assembly 300 is described below.

[0034] Refer to Figure 9 The stator 310 is fixedly connected with the central shaft 100 through the stepped fixing piece 330. In the direction from the head end to the tail end of the stator-rotor assembly 300, the inner diameters of the plurality of stators 310 gradually decrease. The stepped fixing piece 330 is fixedly connected with the central shaft 100 through a key. The stepped fixing piece 330 has a plurality of bosses with different outer diameters, and in the direction from the head end to the tail end of the stator-rotor assembly 300, the outer diameters of the plurality of bosses gradually decrease. The end face of the stator 310 abuts against the end face of the boss of the stepped fixing piece 330, and the stator 310 is fixedly connected with the stepped fixing piece 330 by screws.

[0035] The non-tail end rotor 320 is fixedly connected with the box body 210 through a fixing ring. The fixing ring is integrally formed with the inner wall of the box body 210. In the direction from the head end to the tail end of the stator-rotor assembly 300, the inner diameters of the plurality of fixing rings gradually increase, and the outer diameters of the plurality of rotors 320 gradually increase. The rotor 320 is fixed on the corresponding fixing ring by screws or the like. In this embodiment, since there are three rotors 320, two fixing rings are provided, which are a first fixing ring 341 and a second fixing ring 342, and the inner diameter of the first fixing ring 341 is larger than that of the second fixing ring 342.

[0036] In the installation process of the stator-rotor assembly 300, first, the first end rotor 320 is installed on the second fixed ring 342, second, one stator 310 is installed on the stepped fixed part 330, then the middle rotor 320 is installed on the first fixed ring 341, and then the other stator 310 is installed on the stepped fixed part 330, and finally, the cover plate 220 is fixedly installed with the box 210, and the end rotor 320 integrated with the cover plate 220 and the rest of the parts together form the stator-rotor assembly 300.

[0037] It should be noted that the ordinal numbers such as "first" and "second" cited in the present application are merely identifiers and have no other meaning, such as a specific order. Moreover, for example, the term "first component" does not imply the existence of a "second component" per se, and the term "second component" does not imply the existence of a "first component" per se.

[0038] The "coaxial", "parallel" and the like described in the present application allow for a reasonable range of tolerances. In the present application, the term "axial" refers to the direction of the center axis of a cylindrical object, i.e., the direction common to the center axis; "radial" is perpendicular to "axial", i.e., the direction of the radius or diameter of the end face circle of the cylinder; "circumferential" refers to the "circumferential direction", i.e., the direction around the axis of the cylinder, which together with "axial" and "radial" forms the three orthogonal directions of cylindrical coordinates.

[0039] In order to better demonstrate the inventive points of the present application, some conventional structures inside the motor, such as bearings, wiring harnesses, etc., are omitted in the drawings and the specification, which are features or structures known to those skilled in the art and are not described in detail in the present application. In addition, in order to more clearly show the structure of the present application, some structures in the drawings are proportionally enlarged, and therefore, the size proportions shown in the drawings do not limit the scope of the present application.

[0040] The "present embodiment", "another embodiment" or similar expressions cited in the specification of the present application mean that the features or structures related to the embodiment are included in at least one embodiment disclosed in the present application. Therefore, those skilled in the art can obtain new alternatives by combining the features between different embodiments, and the alternatives should be covered within the protection scope of the present application.

Claims

1. A multi-disc wheel motor, characterized by: It comprises a shaft, a housing assembly and a stator-rotor assembly; wherein, The shaft is fixedly arranged; The housing assembly comprises a box and a cover plate, which combine to form a closed internal space, and the stator-rotor assembly is arranged in the internal space; The stator-rotor assembly comprises a plurality of stators and a plurality of rotors arranged axially at intervals, the plurality of stators are fixedly connected with the shaft, the plurality of rotors are fixedly connected with the housing assembly, and a single stator is located between two adjacent rotors to form an axial magnetic flux path.

2. The multi-disc wheel motor according to claim 1, characterized in that: The stator adopts a printed circuit board stator, which comprises a substrate; a plurality of groups of windings are etched on the substrate, and the plurality of groups of windings are arranged rotationally symmetrically about the central axis of the substrate.

3. A multi-disc wheel motor according to claim 1 or 2, characterized in that: One of the rotors is integrated with the cover plate, and the rotor comprises a plurality of permanent magnets, which are arranged rotationally symmetrically about the central axis of the cover plate, and the permanent magnets are fixedly connected to the cover plate directly or indirectly.

4. The multi-disc wheel motor according to claim 1 or 2, characterized in that: The rotor comprises a rotor disc and a plurality of permanent magnets, which are arranged rotationally symmetrically about the central axis of the cover plate, and the rotor disc has an installation slot for the permanent magnets on the end face, and the installation slot does not penetrate the rotor disc.

5. The multi-disc wheel motor according to claim 1 or 2, characterized in that: The rotor comprises two rotor discs and a plurality of permanent magnets, which are arranged rotationally symmetrically about the central axis of the cover plate, and the rotor disc has an installation slot for the permanent magnets on the end face, and the installation slot penetrates the rotor disc; the two rotor discs are each provided with an outer retaining ring and an inner retaining ring on the side facing away from each other, the outer retaining ring partially shields one end of the installation slot in the radial direction, and the inner retaining ring partially shields the other end of the installation slot in the radial direction.

6. The multi-disc wheel motor of claim 1, wherein: The box comprises end plates, side plates and two flanges fixedly connected with each other; the cover plate comprises end plates and an inner rim fixedly connected with each other; wherein the end plates are used to shield the end face of the whole motor, the side plates are used to shield the circumferential side of the whole motor, the two flanges protrude from the outer surface of the side plates to provide limiting for the hub, and the inner rim protrudes from the inner end face of the cover plate to fit with the inner circumferential side of the side plates.

7. The multi-disc wheel motor of claim 2, wherein: The stator is fixedly connected with the shaft through a stepped fixing piece, the stepped fixing piece is directly or indirectly in interference fit with the shaft, and the stepped fixing piece has a plurality of bosses with different outer diameters; in the direction towards the cover plate, the inner diameters of the plurality of stators gradually decrease, and the outer diameters of the plurality of bosses gradually decrease.

8. The multi-disc wheel motor of claim 1, wherein: The rotor is fixedly connected with the box through a fixing ring, the box and the fixing ring are directly or indirectly fixedly connected, in the direction towards the cover plate, the inner diameters of the plurality of fixing rings gradually increase, and the outer diameters of the plurality of rotors gradually increase.

9. The multi-disc wheel motor of claim 1, wherein: The number of the rotors is one more than the number of the stators.

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