WO2011096658A2

WO2011096658A2 - Traction motor module

Info

Publication number: WO2011096658A2
Application number: PCT/KR2011/000420
Authority: WO
Inventors: Hongshik Yun
Original assignee: Lg Innotek Co., Ltd.
Priority date: 2010-02-03
Filing date: 2011-01-21
Publication date: 2011-08-11
Also published as: WO2011096658A3

Abstract

The present invention relates to a traction motor module, the module including a fixing shaft formed with a flange unit, a traction motor including a housing fixed at the fixing shaft, a stator fixed at an inner lateral wall of the housing, a rotation shaft arranged at a space formed by the stator and protruded from the housing, and a rotor including a magnet arranged between the stator and the rotation shaft, and a hub unit encompassing the traction motor in a cylindrical shape and rotatably coupled to the fixing shaft.

Description

TRACTION MOTOR MODULE

The teachings in accordance with the exemplary embodiments of this invention relate generally to a traction motor module, and more particularly to a traction motor module applicable to a motor bicycle and a motor scooter.

There have been recently proposed numerous technical developments to reduce carbon emissions worsening a global warming. As a result, green motor devices such as motor bicycles that do not emit carbons have been developed of late.

Prior art motor bicycle is configured in such a manner that an electric motor is mounted at a rotational center of a wheel of the bicycle, and a rotational force of the electric motor is used to allow a user to operate the bicycle with a small power. In the prior art motor bicycle, the electric motor is coupled to a fixing shaft, which is in turn connected to a handle of the bicycle, and to frames each arranged to one side of the wheel and to the other side opposite to the said one side.

Furthermore, a stator of the electric motor of the prior art motor bicycle is connected to the fixing shaft, where the fixing shaft includes a core coupled to the fixing shaft, and a coil wound on the core, and a rotor is arranged about the stator, while the rotor includes a magnet arranged about the core.

The rotor of the prior art motor bicycle is arranged at a rotational center of the wheel, and coupled to a rotating body that rotates relative to the fixing shaft.

That is, the prior art motor bicycle is operated on a principle that a core wound by a coil is fixed to a fixing shaft, and a rotating body coupled to a rotor is rotated in response to rotation of the rotor arranged about the core to rotate wheels.

In the prior art motor bicycle, it is difficult to increase the number of cores due to the fact that the core wound by coil is mounted on the fixing shaft having a very small diameter coupled to the frames, whereby it is difficult to apply an electric motor such as a three-phase motor, and in order to increase the number of cores arranged on the fixing shaft for implementing an electric motor such as a three-phase motor, there is a need for a separate part for mounting the core to the fixing shaft, from which structural shortcomings arise to increase the size and weight of the electric motor mounted on the motor bicycle.

Another structural shortcoming in the prior art motor bicycle is that a transmission must be separately mounted outside of the electric motor to reduce revolution of the electric motor to thereby increase the size of the electric motor.

Still another structural shortcoming in the prior art motor bicycle is that frames are arranged on one side and the other side of the wheel, and the fixing shaft is connected to the frames to inevitably increase the width of bicycle, whereby it is difficult to fold and store the bicycle.

The present invention is directed to provide a motor bicycle having a structure suitable for folding and storing the motor bicycle by greatly reducing size and weight through structural improvement of an electric motor.

The present invention is directed to provide a traction motor module free from destruction of a fixing shaft and/or a housing by a large load applied from outside through improvement of the fixing shaft and the housing of an electric motor.

The present invention is directed to provide a transmission pin for mounting a transmission to an electric motor, and to provide a traction motor module free from increased size of the electric motor by using the transmission pin.

The present invention is directed to provide a traction motor module free from an excessive stress directly applied to a traction motor through rotation of a hub unit by fixing a stator of the traction motor to a fixing shaft and arranging a rotor to an inner side of the stator to allow a rotation shaft to be rotatably supported by a motor bearing, arranging the hub unit encompassing the traction motor to an outside of the traction motor, and arranging a hub bearing to the hub unit.

The present invention is directed to provide a traction motor configured to reduce the number of parts, size and weight of an electric motor by improving structure of a rotation shaft in the electric motor.

The present invention is directed to provide a traction motor configured to reduce size of the traction motor module by arranging a rotor including a magnet to a rotation shaft, arranging a stator including a coil about the rotor, improving a structure of a housing to enable a secure fixture of the stator, and improving a rotational force inside the stator relative to the housing.

Technical problems to be solved by the present invention are not restricted to the above-mentioned, and any other technical problems not mentioned so far will be clearly appreciated from the following description by skilled in the art.

An object of the invention is to solve at least one or more of the above problems and/or shortcomings in a whole or in part and to provide at least the advantages described hereinafter. In order to achieve at least the above object, in whole or in part, and in accordance with the purposes of the invention, as embodied and broadly described, and in one general aspect of the present invention, there is provided a traction motor module, the module comprising: a fixing shaft formed with a flange unit; a traction motor including a housing fixed at the fixing shaft, a stator fixed at an inner lateral wall of the housing, a rotation shaft arranged at a space formed by the stator and protruded from the housing, and a rotor including a magnet arranged between the stator and the rotation shaft; and a hub unit encompassing the traction motor in a cylindrical shape and rotatably coupled to the fixing shaft.

Preferably, the housing includes a first housing taking the shape of a plate and coupled to the flange unit, and a second housing accommodating the stator and the rotor and coupled to the first housing.

Preferably, the first housing is formed with a lug unit encompassing a lateral surface of the flange unit, where the lug unit is formed with a strength reinforcement unit by extending a part thereof toward the flange unit for reinforcing a coupling strength of the first housing.

Preferably, the lug unit protruded from the first housing in a circular shape.

Preferably, at least two strength reinforcement units are formed on the lug unit, each spaced apart at a same distance.

Preferably, an upper surface of the lug unit is arranged at a higher position than that of the flange unit.

Preferably, the strength reinforcement unit is brought into contact with the upper surface of the flange unit.

Preferably, the traction motor module further includes at least one fastening screw for fastening the flange unit and the first housing.

Preferably, the rotation shaft is inserted into a pin hole that goes through a floor plate connected to a lateral wall of the housing, where one lateral distal end is arranged on the same planar surface as that of an inner lateral surface of the floor plate, and the other lateral distal end opposite to the said one lateral distal end further includes a transmission gear pin protruded from an external lateral surface opposite to the inner lateral surface of the floor plate.

Preferably, the transmission gear pin includes a fixing unit having a first diameter and inserted into the pin hole, and a transmission gear coupling unit having a second diameter larger than the first diameter.

Preferably, a bushing unit is formed about the pin hole coupled to the transmission gear pin, where the bushing unit is protruded from the external lateral surface of the floor plate with a predetermined thickness.

Preferably, the transmission gear pin includes a fixing unit having a first diameter and inserted into the pin hole, and a transmission gear coupling unit having a second diameter smaller than the first diameter.

Preferably, the traction motor module further includes a ring-shaped first reduction gear formed along an inner lateral surface of the hub unit and formed at an inner surface with a first tooth set, a second reduction gear rotatably fixed at the transmission gear pin protruded from the external lateral surface of the floor plate and formed at a peripheral surface thereof with a second tooth set meshed with the first tooth set, and a third reduction gear coupled to the rotation shaft protruded from the housing and formed at a peripheral surface thereof with a third tooth set meshed with the second tooth set.

Preferably, the traction motor module further includes an insulation sheet interposed between the inner lateral surface of the floor plate and the rotor to prevent the rotor from contacting the floor plate.

Preferably, the traction motor module further includes a pair of motor bearings arranged on the housing to rotatably support the rotation shaft, and a pair of hub bearings arranged on the hub unit to rotatably support the hub unit relative to the traction motor.

Preferably, the housing includes a plate-shaped first housing, and a second housing coupled to the cylindrically shaped first housing, where the motor bearings include a first motor bearing coupled to the first housing and a second motor bearing coupled to the second housing.

Preferably, the second motor bearing is coupled to a burring unit protruded from the second housing toward an inner side.

Preferably, the hub unit includes a cylindrically shaped first hub unit encompassing part of the fixing shaft and the traction motor, and a plate-shaped second hub unit coupled to the first hub unit, and the hub bearings include the first hub bearing interposed between the first hub unit and the fixing shaft, and a second hub bearing coupled to the second hub unit.

Preferably, the traction motor module further includes a transmission unit interposed between a lateral wall of the housing protruded with the rotation shaft and a lateral wall of the hub unit opposite to the lateral wall of the housing to change a speed ratio between the rotation shaft and the hub unit.

Preferably, the rotor includes a rotor core coupled to the rotation shaft and mounted with the magnet, and further includes a transmission unit interposed between a lateral wall of the housing protruded with the rotation shaft and a lateral wall of the hub unit opposite to the lateral wall of the housing to change a speed ratio between the rotation shaft and the hub unit, where the rotation shaft includes a transmission gear unit formed at a distal lateral end of the rotation shaft protruded from the housing and formed with transmission tooth set to be coupled to the transmission unit.

Preferably, the rotation shaft includes a first bearing coupling unit arranged near the transmission gear unit, a rotor coupling unit arranged near the first bearing coupling unit, and a second bearing coupling unit arranged near the rotor coupling unit.

Preferably, the first and second bearing coupling units are coupled to first and second bearings coupled to the housing, and the rotor coupling unit is coupled to the rotor core fixed by the magnet.

Preferably, the rotor coupling unit is lengthwise formed with at least one rotor core rotation prevention unit along a peripheral surface of the rotation shaft for preventing the rotor core and the rotation shaft from slipping.

Preferably, the rotation shaft further includes a yoke coupling unit interposed between the rotor coupling unit and the second bearing coupling unit, where the yoke coupling unit is coupled to a yoke burring unit of a yoke.

Preferably, the yoke coupling unit is lengthwise formed with at least one yoke rotation preventing unit along a peripheral surface of the rotation shaft for preventing the yoke burring unit and the rotation shaft from slipping.

Preferably, each of the transmission gear unit, the first bearing coupling unit, the rotor coupling unit and the second bearing unit is formed with a sequentially reducing diameter.

Preferably, each of the transmission gear unit, the first bearing coupling unit, the rotor coupling unit and the second bearing unit is arranged on the same rotational center.

Preferably, the transmission unit includes a ring-shaped ring gear formed along an inner surface of the hub unit and formed thereinside with a tooth set, and a planetary gear rotatably fixed at a transmission gear pin protruded from an external lateral surface of the floor plate of the housing and formed at a peripheral surface thereof with a tooth set meshed with the tooth set of the ring gear and a tooth set of the transmission gear unit of the rotation shaft.

Preferably, the housing of the traction motor includes a first housing fixed to the fixing shaft and a second housing coupled to the first housing, the traction motor includes first and second bearings each arranged on the first and second housing, and coupled to the rotation shaft, the rotor includes a rotor core formed with a hollow hole and mounted with the magnet, and a rotation shaft support bar connecting the rotation shaft to the inner surface of the rotor core, and at least part of any one of the first and second bearings is arranged inside the hollow hole of the rotor core.

Preferably, the first bearing is fixed to the housing, the second bearing is fixed to the second housing, and part of the first and second bearings is arranged inside the hollow hole of the rotor core.

Preferably, at least two rotation shaft support bars are arranged, each spaced apart at a same distance.

Preferably, the traction motor module further includes a yoke body arranged at one lateral distal end of the rotor core opposite to the first housing, and a yoke extended from the yoke body and formed with a yoke burring unit coupled to the rotation shaft, and part of the yoke burring unit is arranged inside the hollow hole of the rotor core.

Preferably, at least part of the second bearing is arranged inside the hollow hole of the rotor core.

Preferably, the traction motor module further includes a magnet sensor arranged on the yoke body, and a circuit substrate arranged on the first housing opposite to the yoke body and opposite to the magnet sensor.

Preferably, a lateral distal end of the rotation shaft is protruded from the housing, and a lateral wall of the housing includes a first fixing unit press-fitted into the external lateral surface of the stator, and a second fixing unit supporting a lateral distal end of the stator.

Preferably, the lateral wall of the housing opposite to the first fixing unit has a first thickness, and the lateral wall of the housing opposite to the second fixing unit has a second thickness thicker than the first thickness.

Preferably, the first fixing unit is formed with a rotation prevention unit protruded from the first fixing unit, and the external lateral surface of the stator opposite to the rotation prevention unit is formed with a rotation prevention groove.

Preferably, at least two rotation prevention units are formed at the housing along the first fixing unit of the housing, and include any one shape of a rib or a lug.

Preferably, the first fixing unit is formed with a concave rotation prevention groove for preventing the stator from rotating, and a part opposite to the rotation prevention groove in the external lateral surface of the stator is formed with a rotation prevention unit protruded from the external lateral surface of the stator.

Preferably, at least two rotation prevention grooves formed at the housing are formed along the first fixing unit, and each of the rotation prevention grooves formed at the housing takes the shape of a groove.

Preferably, any one of a groove or a lug is formed at the lateral distal end of the stator, and the second stator opposite to the lateral distal end of the stator is formed with any one of a groove or a lug coupled to the groove or lug of the stator.

Preferably, the lateral distal end of the stator is formed with a groove.

Preferably, the lateral distal end of the stator is formed with a lug.

Preferably, the rotor includes a coupling piece having a same curvature as that of the housing, and a stator block including a lug unit protruded from an inner surface of the coupling piece toward a center of the housing, where a plurality of stator blocks are coupled, in a ring shape, along the inner surface of the housing, and an external lateral surface of the coupling piece is formed with a rotation prevention groove, and the inner surface of the housing opposite to the rotation prevention groove is formed with a lug-shaped rotation prevention unit.

Preferably, the traction motor module further includes a frame position determining washer inserted into the fixing shaft to determine a position of the frame fixed to the fixing shaft.

Preferably, a space is formed between a lateral wall of the housing protruded with the rotation shaft and the hub unit opposite to the lateral wall to accommodate a transmission unit for changing a speed ratio between the rotation shaft and the hub unit.

In another general aspect of the present invention, there is provided a traction motor module, the module comprising: a fixing shaft fixed at a frame; a traction motor including a housing fixed at the fixing shaft, cores fixed at an inner lateral wall of the housing, a rotation shaft arranged at a space formed by the cores and protruded from the housing, and a magnet arranged between the rotation shaft and the cores and coupled to the rotation shaft; a hub unit encompassing the traction motor in a cylindrical shape and rotatably coupled to the fixing shaft; and a transmission unit arranged between the lateral wall of the housing protruded with the rotation shaft and the lateral wall of the hub unit opposite to the lateral wall to change a speed ratio between the rotation shaft and the hub unit.

Preferably, the transmission unit includes a first reduction gear formed along an inner lateral surface of the hub unit and formed at an inner surface with a first tooth set, at least one second reduction gear rotatably fixed at the housing and formed at a peripheral surface thereof with a second tooth set meshed with the first tooth set, and a third reduction gear coupled to the rotation shaft protruded from the housing and formed at a peripheral surface thereof with a third tooth set meshed with the second tooth set.

Preferably, the first reduction gear includes a ring gear formed at an inner lateral surface thereof with the first tooth set, and the second reduction gear includes a planetary gear formed at an external lateral surface thereof with the second tooth set.

In still another general aspect of the present invention, there is provided a traction motor module, the module comprising: a fixing shaft fixed to a frame; a fixing shaft fixed at a frame; a traction motor including a housing fixed at the fixing shaft, cores fixed at an inner lateral wall of the housing, a rotation shaft arranged at a space formed by the cores and protruded from the housing, and a magnet arranged between the rotation shaft and the cores and coupled to the rotation shaft; a hub unit encompassing the traction motor in a cylindrical shape and rotatably coupled to the fixing shaft; and a transmission unit arranged between the lateral wall of the housing protruded with the rotation shaft and the lateral wall of the hub unit opposite to the lateral wall to change a speed ratio between the rotation shaft and the hub unit, wherein the frame is asymmetrically formed at one side of a wheel connected to the hub unit among the one side of the wheel and the other side opposite to the one side.

Preferably, the frame includes a first frame unit arranged on a straight line with the wheel, and a second frame unit bent from the first frame and extended to the one side of the wheel, wherein the fixing shaft is coupled to the second frame unit.

The traction motor module according to the present invention has an advantageous effect in that a motor bicycle is provided having a structure suitable for folding and storing the motor bicycle by greatly reducing size and weight through structural improvement of an electric motor.

The traction motor module according to the present invention has an advantageous effect in that it is free from destruction of a fixing shaft and/or a housing by a large load applied from outside through improvement of the fixing shaft and the housing of an electric motor.

The traction motor module according to the present invention has an advantageous effect in that a transmission pin is provided for mounting a transmission to an electric motor, and the traction motor module is free from increased size of the electric motor by using the transmission pin.

The traction motor module according to the present invention has an advantageous effect in that it is free from an excessive stress directly applied to a traction motor through rotation of a hub unit by fixing a stator of the traction motor to a fixing shaft and by arranging a rotor to an inner side of the stator to allow a rotation shaft to be rotatably supported by a motor bearing, by arranging the hub unit encompassing the traction motor to an outside of the traction motor, and by arranging a hub bearing to the hub unit.

The traction motor module according to the present invention has an advantageous effect in that a traction motor is provided that is configured to reduce the number of parts, size and weight of an electric motor by improving structure of a rotation shaft in the electric motor.

The traction motor module according to the present invention has an advantageous effect in that a traction motor is provided that is configured to reduce size of the traction motor module by arranging a rotor including a magnet to a rotation shaft, arranging a stator including a coil about the rotor, improving a structure of a housing to enable a secure fixture of the stator, and improving a rotational force inside the stator relative to the housing.

The teachings of the present invention can be readily understood by considering the following detailed description in conjunction with the accompanying drawings, in which:

FIG.1 is a partially cut perspective view illustrating a traction motor module according to a first exemplary embodiment of the present invention;

FIG.2 is a cross-sectional view illustrating the traction motor module of FIG.1;

FIG.3 is an exploded perspective view illustrating a traction motor of FIG.1;

FIG.4 is a plan illustrating a stator of FIG.3;

FIG.5 is a partially cut perspective view illustrating a traction motor module according to another exemplary embodiment of the present invention;

FIG.6 is a cross-sectional view illustrating a traction motor module of FIG.5;

FIG.7 is a perspective view illustrating a transmission unit arranged at a rear surface of the traction motor of FIG.5;

FIG.8 is a perspective view illustrating a bicycle coupled with a traction motor module according to an exemplary embodiment of the present invention;

FIG.9 is a front view taken from 'A' direction of FIG.8;

FIG.10 is a partially cut perspective view illustrating a traction motor module according to a second exemplary embodiment of the present invention;

FIG.11 is a cross-sectional view illustrating a traction motor module of FIG.10;

FIG.12 is an exploded perspective view illustrating a traction motor of FIG.10;

FIG.13 is a perspective view illustrating a first housing and a fixing shaft of FIG.12;

FIG.14 is a perspective view illustrating a first housing of FIG.13;

FIG.15 is a partially enlarged view of 'B' part of FIG.14;

FIG.16 is a partially cut perspective view illustrating a traction motor module according to a third exemplary embodiment of the present invention;

FIG.17 is an exploded perspective view illustrating a traction motor of FIG.16;

FIG.18 is a perspective view illustrating a rear surface of the traction motor of FIG.17;

FIG.19 is an exploded perspective view illustrating a traction motor module of FIG.16;

FIG.20 is a partially enlarged view of 'C' part of FIG.19;

FIG.21 is a cross-sectional view illustrating a traction motor module according to another exemplary embodiment of the present invention;

FIG.22 is a partially enlarged view of 'D' part of FIG.21;

FIG.23 is a partially cut perspective view illustrating a traction motor module according to a fourth exemplary embodiment of the present invention;

FIG.24 is a partially cut perspective view illustrating a traction motor module of FIG.23;

FIG.25 is a cross-sectional view illustrating a traction motor module of FIG.23;

FIG.26 is a partially cut perspective view illustrating a traction motor module according to a fifth exemplary embodiment of the present invention;

FIG.27 is a cross-sectional view illustrating a traction motor module of FIG.26;

FIG.28 is an exploded perspective view illustrating a traction motor module of FIG.27;

FIG.29 is an exploded perspective view illustrating a rotor;

FIG.30 is a lateral view illustrating a rotation shaft of a rotor of FIG.27;

FIG.31 is a partially cut perspective view illustrating a traction motor module according to a sixth exemplary embodiment of the present invention;

FIG.32 is a cross-sectional view illustrating a traction motor module of FIG.32;

FIG.33 is a partially enlarged view of 'E' part of FIG.32;

FIG.34 is an exploded perspective view illustrating a rotor of FIG.32;

FIG.35 is a cross-sectional view illustrating a traction motor module according to another exemplary embodiment of the present invention;

FIG.36 is an exploded perspective view illustrating a rotor of FIG.35;

FIG.37 is an enlarged view illustrating 'F' part of FIG.35;

FIG.38 is a partially cut perspective view illustrating a traction motor module according to a seventh exemplary embodiment of the present invention;

FIG.39 is a cross-sectional view illustrating a traction motor module of FIG.28;

FIG.40 is an exploded perspective view illustrating a second housing and a stator of FIG.39;

FIG.41 is a plan view illustrating a second housing and a stator according to another exemplary embodiment of the present invention;

FIG.42 is a plan view illustrating a second housing and a stator according to still another exemplary embodiment of the present invention; and

FIG.43 is a plan view illustrating a second housing and a stator according to still another exemplary embodiment of the present invention.

The following description is not intended to limit the invention to the form disclosed herein. Consequently, variations and modifications commensurate with the following teachings, and skill and knowledge of the relevant art are within the scope of the present invention. The embodiments described herein are further intended to explain modes known of practicing the invention and to enable others skilled in the art to utilize the invention in such, or other embodiments and with various modifications required by the particular application(s) or use(s) of the present invention.

The disclosed embodiments and advantages thereof are best understood by referring to FIGS. 1-43 of the drawings, like numerals being used for like and corresponding parts of the various drawings. Other features and advantages of the disclosed embodiments will be or will become apparent to one of ordinary skill in the art upon examination of the following figures and detailed description. It is intended that all such additional features and advantages be included within the scope of the disclosed embodiments, and protected by the accompanying drawings. Further, the illustrated figures are only exemplary and not intended to assert or imply any limitation with regard to the environment, architecture, or process in which different embodiments may be implemented. Accordingly, the described aspect is intended to embrace all such alterations, modifications, and variations that fall within the scope and novel idea of the present invention.

It will be understood that the terms "comprises" and/or "comprising," or "includes" and/or "including" when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or groups thereof. That is, the terms "including", "includes", "having", "has", "with", or variants thereof are used in the detailed description and/or the claims to denote non-exhaustive inclusion in a manner similar to the term "comprising".

Furthermore, "exemplary" is merely meant to mean an example, rather than the best. It is also to be appreciated that features, layers and/or elements depicted herein are illustrated with particular dimensions and/or orientations relative to one another for purposes of simplicity and ease of understanding, and that the actual dimensions and/or orientations may differ substantially from that illustrated. That is, in the drawings, the size and relative sizes of layers, regions and/or other elements may be exaggerated or reduced for clarity. Like numbers refer to like elements throughout and explanations that duplicate one another will be omitted. Now, the present invention will be described in detail with reference to the accompanying drawings.

As may be used herein, the terms "substantially" and "approximately" provide an industry-accepted tolerance for its corresponding term and/or relativity between items. Such an industry-accepted tolerance ranges from less than one percent to ten percent and corresponds to, but is not limited to, component values, angles, et cetera. Such relativity between items ranges between less than one percent to ten percent.

FIRST EXEMPLARY EMBODIMENT

FIG.1 is a partially cut perspective view illustrating a traction motor module according to a first exemplary embodiment of the present invention, and FIG.2 is a cross-sectional view illustrating the traction motor module of FIG.1.

Referring to FIGS.1 and 2, the traction motor module (1000) includes a fixing shaft (50), a traction motor (100) and a hub unit (200).

The fixing shaft (50) takes the shape of a metal pipe having a hollow hole (52) as shown in FIG.2, for example. The fixing shaft (50) may be connected to a frame for changing directions of a bicycle by being connected to a bicycle handle. A lateral surface of the fixing shaft (50) is formed with at least one through hole (54), and a distal end of the fixing shaft (50) is formed with a flange unit (56) bent outside relative to the fixing shaft (50). The fixing shaft (50) is inserted by a frame position determination washer (58), which determines a position of the frame fixed to the fixing shaft (50).

FIG.3 is an exploded perspective view illustrating a traction motor of FIG.1.

Referring to FIGS. 2 and 3, the traction motor (100) includes a housing (110), a stator (120) and a rotor (130). The housing (110) includes a first housing (112) and a second housing (118).

The first housing (112) includes a disc-shaped first through hole (111) at a rotational center thereof, and three second through holes (111a) about the first through hole (111) of the first housing (112), for example. Part of the second through holes (111a) arranged about the first through hole (111) are extended toward the first through hole (111), whereby each of the first and second through holes (111, 111a) takes the shape of a letter "T" when viewed on a plan, whereby the first and second through holes (111, 111a) are intercommunicated.

The first housing (112) is arranged thereon with a flange unit (56) of the fixing shaft (50), where the first housing (112) and the flange unit (56) of the fixing shaft (50) are securely fastened by a screw or the like.

The hollow hole (52) at the fixing shaft (50) is formed at a position corresponding to that of the first through hole (111) of the first housing (112), whereby the first through hole (111) and the hollow hole (52) are intercommunicated. The part extended to be connected to the first through hole (111) in the second through holes (111a) is covered by the flange unit (56). A space formed by the flange unit (56) and the part extended to be connected to the first through hole (111) in the second through holes (111a) is passed by a wiring for applying a driving signal to a coil wound on a stator core of a stator (described later).

The first housing (112) is arranged at an inner lateral surface thereof with a doughnut-shaped circuit substrate (113), where the circuit substrate (113) is formed with a through hole corresponding to the hollow hole (52) of the fixing shaft (50).The circuit substrate (113) is arranged with a revolution count sensor (113a) for detecting a revolution count and/or revolution speed of a rotor (described later).

The second housing (118) takes the shape of an upper surface-opened cylinder. The second housing (118) includes a lateral wall (114), and a floor plate (116) blocking a floor of the lateral wall (114). The lateral wall (114) and the floor plate (116) may be integrally formed in the first exemplary embodiment of the present invention, for example.

The floor plate (116) of the second housing (118) is centrally formed with a burring unit (116b) formed with a through hole (116a).The through hole (116a) centrally formed at the second housing (118) is protruded with a rotation shaft of a rotor (described later).

Referring to FIG.1 again, one to three pins (117) are arranged about the through hole (116a) of the floor plate (116) at the second housing (118). E ach pin (117) arranged on the floor plate (116) of the second housing (118) is coupled with a planetary gear (not shown) of a transmission unit (not shown), and the each planetary gear is rotated at a designated position by the pins (117). The second housing (118) is fastened to the first housing (112) by a fastening screw or the like.

FIG.4 is a plan illustrating a stator of FIG.3.

Referring to FIGS. 2 and 4, a stator (120) is arranged in an accommodation space formed by the lateral wall (114) of the second housing (118) and the floor plate (116), and the stator (120) is fixed inside the housing (110) fixed by the fixing shaft (50).

The stator (120) according to the first exemplary embodiment of the present invention includes a plurality of stator blocks (126), where the stator (120) may include 12 stator blocks (126), for example.

Each stator block (126) includes a stator core (122) and a coil (124) as shown in FIG.4. The stator core (122) takes the shape of a letter "H" when viewed on a plan, and is formed by laminating a plurality of thin "H" shaped steel pieces. The coil (124) is wound on a concave portion of the stator core (122) in the predetermined coil turns. The stator core (122) and the coil (124) at each stator block (126) are insulated from each other by an insulator (not shown).

Due to assembled plurality of block-shaped stator blocks (126) including the coil (124) wound on the stator core (122), the stator (120) takes the shape of a ring when viewed on a plan. The stator (120) shaped in a ring by the assembled 12 stator blocks (126) is fixed inside the accommodation space of the second housing (118) at the housing (110).

In the first exemplary embodiment of the present invention, due to the fact that the stator (120) shaped in a ring by the assembled 12 stator blocks (126) is arranged in the accommodation space of the second housing (118), a much larger number of stator blocks, e.g., 12, can be arranged inside the second housing (118) over a conventional arrangement of stator in the fixing shaft (50).

Particularly, due to the fact that the stator blocks are manufactured by winding the coil (124) on each stator core (122), and the stator (120) is manufactured by assembly of manufactured stator blocks, the stator (120) having more stator blocks on a limited unit area can be realized. Meanwhile, the stator core (122) with tightly wound coil (124) cannot be implemented from the conventional structure where a coil is wound on an integrated stator core.

Referring again to FIGS. 2 and 3, the rotor (130) includes a rotation shaft (132), a rotor core (134) and a magnet (136). In addition, the rotor (130) may further include a yoke (138) and a magnet sensor (139).

The rotation shaft (132) is arranged in a hollow hole formed by the stator (120) arranged along an inner lateral surface of the second housing (118) at the housing (110). A gap is formed between a periphery of the rotation shaft (132) and an inner circumferential surface of the stator (120), and the rotation shaft (132) is centrally arranged in the stator (120).

One distal end of the rotation shaft (132) is rotatably coupled to the first housing (112), and the other distal end opposite to the one distal end of the rotation shaft (132) is protruded toward the outside through the through hole (116a) of the floor plate (116) at the second housing (118).

The other distal end of the rotation shaft protruded from the floor plate (116) of the second housing (118) may be coupled to a sun gear (136) coupled to the transmission unit.

Referring again to FIG.2, the one distal end of the rotation shaft (132) is rotatably fixed by a bearing (133) arranged on the first housing (112), and the other distal end of the rotation shaft (132) is rotatably fixed by a bearing (135) coupled to an inner lateral surface of the burring unit (116b) formed on the floor plate (116) of the second housing (112).

The rotor core (134) takes the shape of a pipe having a hollow hole. The rotor core (134) is manufactured with a material suitable for passing a magnet flux generated by the magnet (136, described later) without any loss.

A plurality of rotation shaft support units (134a), e.g., four units, may be protruded from an inner lateral surface of the rotor core (134) formed by the hollow hole of the rotor core (134). The four rotation shaft support units (134a) protruded from the inner lateral surface of the rotor core (134) are connected to a center of the rotor core (134) to form a rotation shaft hole press-fitted by the rotation shaft (132).

The rotor core (134) may include grooves formed at an upper surface of the rotor core (134) and formed toward the bottom surface opposite to the upper surface, or through holes (137) that pass through the upper surface and the bottom surface of the rotor core (134), where the rotor core (134) may be formed with eight through holes (137), for example.

The through holes (136) of the rotor core (134) may take the shape of a rectangle when viewed on a plan. Alternatively, the rotor core (134) may take the shape of a curve having a same curvature as that of the periphery of the rotor core (134), when viewed on a plan.

The magnet (136) takes the shape of a plate arranged inside the through hole (137) of the rotor core (134). The magnet (136) takes the shape corresponding to that of the through hole (137). For example, in a case the through hole (137) takes the shape of a rectangle when viewed on a plan, the magnet (136) takes the plated shape of a rectangular parallelepiped.

Alternatively, the rotor core (134) may take the shape of a curved plate, in a case the through hole (137) of the rotor core (134)

takes the shape of a curve, when viewed on a plan.

The yoke (138) is arranged on an upper surface of the rotor core (134) to prevent the magnetic flux of the magnet (136) from leaking to other areas than an area of the stator (120). The yoke (138) may take the shape of a metal disc and be fastened to the upper surface of the rotor core (134) using a screw, for example.

The magnet sensor (139) is arranged on the yoke (138) and takes the shape of a doughnut. As shown in FIG.2, the magnet sensor (139) is formed on a position corresponding to that of a magnet sensor (139a) of the circuit substrate (113).

Referring to FIGS. 1 and 2 again, the hub unit (200) encompasses the traction motor (100) to be rotatably arranged relative to the rotation shaft (50). The hub unit (200) includes a first hub unit (225) and a second hub unit (240), where the first hub unit (225) includes a lateral wall (210) and a floor plate (220).

The lateral wall (210) of the first hub unit (225) takes the shape of a cylinder, where the floor plate (220) is arranged on a distal end of the lateral wall (210). An inner circumferential surface of the lateral wall (210) is discrete from a lateral wall (114) of the second housing (118) at the traction motor (100) at a predetermined space to be prevented from being fractionized with the lateral wall (114) of the second housing (118) in a case the lateral wall (210) of the first hub unit (225) is rotated.

Lugs (230) coupled to spokes of the bicycle are protruded from the lateral wall (210) of the first hub unit (225), and the lugs (230) are formed with fixing holes (235) in which that distal ends of the spokes are bent and fixed.

A floor plate (220) of the first hub unit (225) is formed with a bushing unit (227) discrete from a periphery of the fixing shaft (50), and a bearing (228) is interposed between the bushing unit (227) and the periphery of the fixing shaft (50) to allow the first hub unit (225) to rotate. The second hub unit (240) takes the shape of a plate, and is coupled to an opened distal end of the first hub unit (225). The first and second hub units (225, 240) are coupled by a fastening screw or the like.

The second hub unit (240) and a floor surface (116) of the second housing (118) at the housing (110) of the traction motor (100) are discrete from each other at a predetermined gap to form a space (260). To be more specific, a space (260) suitable for mounting a transmission unit for rotating the hub unit (200) at a revolution lower than that of the rotation shaft (132) of the traction motor (100) is formed between the floor surface (116) of the second housing (118) and the second hub unit (240), and in order to mount the transmission unit, the floor surface (116) of the second housing (118) is formed, as mentioned before, with a pin (117) mounted with a planetary gear for rotating the planetary gear.

Meanwhile, a position corresponding to a distal end of the rotation shaft (132) in the second hub unit (240) may be disposed with a bearing (250) for rotatably fixing the rotation shaft (132).

FIG.5 is a partially cut perspective view illustrating a traction motor module according to another exemplary embodiment of the present invention, FIG.6 is a cross-sectional view illustrating a traction motor module of FIG.5, and FIG.7 is a perspective view illustrating a transmission unit arranged at a rear surface of the traction motor of FIG.5.

The traction motor module illustrated in FIGS. 5 through 7 has substantially the same structure as that shown in FIGS. 1 through 4 except for a transmission unit. Like numbers refer to like elements throughout and explanations that duplicate one another will be omitted.

Referring to FIGS. 5 through 7, a traction motor module (1000) includes a fixing shaft (50), a traction motor (100), a hub unit (200) and a transmission unit (300). The transmission unit (300) in the present exemplary embodiment of the present invention will delve into a 1-shift gear transmission unit. Although the exemplary embodiment of the present invention describes a 1-shift gear transmission unit, a multi-shift gear transmission unit capable of multiple shifting may be arranged in the hub unit (200).

The transmission unit (300) functions to change a speed ratio between the rotation shaft (132) and the hub unit (200). For example, the transmission unit (300) changes the revolution count of the hub unit (200) relative to the rotation shaft (132) such that the hub unit (200) can rotate at a revolution lower than that of the rotation shaft (132). The transmission unit (300) includes a first reduction gear (310), a second reduction gear (320) and a third reduction gear (330).

The first reduction gear (310) takes the shape of a ring along an inner lateral surface of the lateral wall (210) of the first hub unit (225) at the hub unit (200), and includes at an inner lateral surface thereof a ring gear formed with a first tooth set (315). The second reduction gear (320) is rotatably fixed at a pin (117) arranged on the floor plate (116) of the second housing (118) at the housing (110) of the traction motor (100), and includes at a periphery a planetary gear formed with a second tooth set (325). In the present exemplary embodiment, the pin (117) is circularly arranged at a 120-degree on the floor plate (116), such that three second reduction gears (320) are arranged on the floor plate (116).

The second tooth set (325) formed at the periphery of the second reduction gear (320) is meshed with the first tooth set (315) of the first reduction gear (310). The third reduction gear (330) is coupled to a rotation shaft protruded from the floor plate (116) of the second housing (118), and may include a sun gear formed at a periphery with a third tooth set (335). The third tooth set (335) formed at the periphery of the third reduction gear (330) is meshed with the second tooth set (325) of the second reduction gear (320).

In the present embodiment, the third tooth set (335) of the third reduction gear (330) is formed with a first number of tooth sets, the second tooth set (325) of the second reduction gear (320) is formed with a second number of tooth sets greater than the first number of tooth sets, and the first tooth set (315) of the first reduction gear (310) is formed with a third number of tooth sets greater than the second number of tooth sets.

Therefore, the second reduction gear (320) is rotated at a revolution lower than that of the rotation shaft (132), as the third reduction gear (330) rotating at the same revolution as that of the rotation shaft (1321) is rotated, and the first reduction gear (310) is rotated at a revolution lower than that of the second reduction gear as the second reduction gear (320) is rotated. The hub unit (200) coupled to the first reduction gear (310) is rotated at a revolution much lower than that of the rotation shaft (132), whereby a user can travel at a stable speed.

FIG.8 is a perspective view illustrating a bicycle coupled with a traction motor module according to an exemplary embodiment of the present invention, and FIG.9 is a front view taken from 'A' direction of FIG.8.

The traction motor module (1000) mounted on a bicycle illustrated in FIGS. 8 and 9 has substantially the same structure as that shown in FIGS. 1 through 7, such that like numbers refer to like elements throughout and explanations that duplicate one another will be omitted.

Referring to FIGS. 8 and 9, a motor bicycle (500) includes a body (530) coupled with a pair of wheels (510, 520), a handle (540) formed on the body (530) for changing directions of a front wheel (510), and a frame (550) coupled to the handle (540).

The frame (550) includes a first frame unit (555) arranged on a straight line with the front wheel (510), and a second frame unit (558) bent from the first frame (555) and asymmetrically extended toward the one side of the front wheel (510), wherein the fixing shaft (50) is coupled to the second frame unit (558).

The frame (550) fixed to the fixing shaft (50) is asymmetrically formed at any one side of the one side or the other side of the front wheel (510) to greatly reduce the size and width of the bicycle (500), whereby a foldable motor bicycle can be implemented.

The traction motor module according to the first exemplary embodiment of the present invention has an advantageous effect in that, due to a structure in which a stator is fixed at an inner lateral surface of a housing of a traction motor, and a rotor is arranged at a rotation shaft, a structure in which a stator is fixed at an inner lateral surface of a housing of a traction motor, and a transmission unit is formed at the housing, and a structure in which a frame is asymmetrically formed at one side of a wheel of a bicycle, and the frame is arranged with a fixing shaft of the traction motor, the size and width of the motor bicycle can be remarkably reduced and a driving performance of the motor bicycle can be further improved.

SECOND EXEMPLARY EMBODIMENT

FIG.10 is a partially cut perspective view illustrating a traction motor module according to a second exemplary embodiment of the present invention, FIG.11 is a cross-sectional view illustrating a traction motor module of FIG.10, and FIG.12 is an exploded perspective view illustrating a traction motor of FIG.10.

Referring to FIGS. 10, 11 and 12, the traction motor module (1000) includes a fixing shaft (50), a traction motor (100), a hub unit (200) and a transmission unit (300).

The fixing shaft (50) takes the shape of a metal pipe having a hollow hole (52) as shown in FIG.11, for example. The fixing shaft (50) may be connected to a frame for changing directions of a bicycle by being connected to a bicycle handle. A lateral surface of the fixing shaft (50) is formed with at least one through hole (54), and a distal end of the fixing shaft (50) is formed with a flange unit (56) bent outside relative to the fixing shaft (50).

The flange unit (56) is formed with a plurality of fastening holes that passes the flange unit (56) and circularly arranged relative to a center of the flange unit (56, as illustrated in FIG.12. The flange unit (56) is formed with a first thickness in the present exemplary embodiment.

The fixing shaft (50) is inserted by a frame position determination washer (58), which determines a position of the frame fixed to the fixing shaft (50).

The traction motor (100) includes a housing (110), a stator (120) and a rotor (130).

Referring to FIGS.11 and 12, the stator (120) includes a plurality of stator blocks (126), where the stator (120) may include 12 stator blocks (126), for example.

Each stator block (126) includes a stator core (122) and a coil (124).The stator core (122) takes the shape of a letter "H" when viewed on a plan, and is formed by laminating a plurality of thin "H" shaped steel pieces. The coil (124) is wound on a concave portion of the stator core (122) in the predetermined coil turns. The stator core (122) and the coil (124) at each stator block (126) are insulated from each other by an insulator (not shown).

Due to the plurality of block-shaped stator blocks (126) assembled by way of press-fitting, including the coil (124) wound on the stator core (122), the stator (120) takes the shape of a ring when viewed on a plan.

In the second exemplary embodiment of the present invention, due to the fact that the stator blocks are manufactured by winding the coil (124) on each stator core (122), and the stator (120) is manufactured by assembly of manufactured stator blocks, the stator (120) having more stator blocks on a limited unit area can be realized. Meanwhile, the stator core (122) with tightly wound coil (124) cannot be implemented from the conventional structure where a coil is wound on an integrated stator core.

Referring again to FIGS. 11 and 12, the rotor (130) includes a rotation shaft (132), a rotor core (134) and a magnet (136). In addition, the rotor (130) may further include a yoke (138) and a magnet sensor (139).

The rotation shaft (132) is arranged in a hollow hole formed by the ring-shaped stator (120). A gap is formed between a periphery of the rotation shaft (132) and an inner circumferential surface of the stator (120), and the rotation shaft (132) is centrally arranged in the stator (120).

A plurality of rotation shaft support units (134a), e.g., four units, may be protruded toward a center of the rotor core (134) from an inner lateral surface of the rotor core (134) formed by the hollow hole of the rotor core (134). The four rotation shaft support units (134a) protruded from the inner lateral surface of the rotor core (134) are connected to a center of the rotor core (134) to form a rotation shaft hole press-fitted by the rotation shaft (132).

Alternatively, the rotor core (134) may take the shape of a curved plate, in a case the through hole (137) of the rotor core (134) takes the shape of the curve, when viewed on a plan.

The yoke (138) is arranged on an upper surface of the rotor core (134) to prevent the magnetic flux of the magnet (136) from leaking to other areas than an area of the stator (120). The yoke (138) may take the shape of a metal disc and be coupled to the rotation shaft (132) by a yoke burring unit (138a).

The magnet sensor (139) is arranged on the yoke (138) and takes the shape of a doughnut. As shown in FIG.2, the magnet sensor (139) is formed on a position corresponding to that of a revolution count sensor (113a) of the circuit substrate (113).

FIG.13 is a perspective view illustrating a first housing and a fixing shaft of FIG.12, FIG.14 is a perspective view illustrating a first housing of FIG.13, and

FIG.15 is a partially enlarged view of 'B' part of FIG.14.

Referring to FIGS. 13 through 15, the housing (110) fixes the stator (120) and rotatably supports the rotor (130) relative to the stator (120).

The first housing (112) is arranged thereon with a flange unit (56) of the fixing shaft (50), where the first housing (112) and fastening holes (57) at the flange unit (56) of the fixing shaft (50) are securely fastened by a fastening screw or the like.

The first housing (112) is formed thereon with a ring-shaped lug unit (112a) encompassing a lateral surface of the flange unit (56) of the fixing shaft (50) having a first thickness. In the present embodiment, the thickness of the lug unit (112a) of the first housing (112) has a second thickness thicker than the thickness of the flange unit (56), such that the upper surface of the lug unit (112a) is positioned at a position higher than that of the upper surface of the flange unit (56).

In a case an excessive stress is applied to the first housing (112) and the flange unit (56) of the fixing shaft (50) fastened to the first housing (112) by a fastening screw, there is a high likelihood of the first housing (112) and the fixing shaft (50) being damaged or separated.

In the present exemplary embodiment, a strength reinforcement unit (112b) is formed at the lug unit (112a) protruded from the upper surface of the first housing (112) that prevents the first housing (112) and the flange unit (56) of the fixing shaft (50) from being damaged or separated. The strength reinforcement unit (112b) is formed by deforming the shape of the lug unit (112a) through application of press to a corner area formed by the upper surface and the inner lateral surface of the lug unit (112a) using a pressing process.

In the present embodiment, the strength reinforcement unit (112b) is extended from the inner lateral surface of the lug unit (112a) to the upper surface of the flange unit (56) of the fixing shaft (50) to further improve a coupling strength between the flange unit (56) and the first housing (112) by contacting the upper surface of the flange unit (56).

At least two or more, preferably, in a plural number, strength reinforcement units (112b) may be formed on the lug unit (112a), each at a predetermined equal distance therebetween.

Although the present exemplary embodiment of the present invention has described a technical feature in which part of the lug unit (112a) is protruded to the upper surface of the flange unit (56) by pressing process to combine the first housing (112) and the flange unit (56), whereby a coupling strength between the first housing (112) and the flange unit (56) is enhanced, it is not limited thereto. For example, at least two coupling grooves may be formed on the lug unit (112a), each discrete at a predetermined equal distance from each other, and the coupling grooves may be press-fitted by a strength reinforcement member that applies pressure to the flange unit (56).

Referring to FIGS. 11 and 12 again, a hollow hole (52) at the fixing shaft (50)is formed at a position corresponding to that of a first through hole (111) of the first housing (112), whereby the first through hole (111) and the hollow hole (52) are intercommunicated.

A portion extended for being connected to the first through hole (111) in second through holes (111a) is covered by the flange unit (56). A wiring for applying a driving signal to a coil wound on a stator core of a stator (described later) passes through a space formed by the portion extended for being connected to the flange unit (56) and the first through hole (111) in second through holes (111a).

An inner lateral surface of the first housing (112) is arranged with a doughnut-shaped circuit substrate (113), which is formed with a through hole corresponding to the hollow hole of the fixing shaft (50). The circuit substrate (113) is arranged with a revolution count sensor (113a) for reducing revolution counts and/or rotational speed of a rotor (described later).

A second housing (118) is fastened to the first housing (112) by a fastening screw. The second housing (118) takes the shape of an upper surface-opened cylinder. The second housing (118) includes a lateral wall (114) and a floor plate (116) blocking a floor of the lateral wall (114). In the present embodiment, the lateral wall (114) and the floor plate (116) are integrally formed.

The floor plate (116) of the second housing (118) is centrally formed with a burring unit (116b) formed with a through hole (116a). a rotation shaft of the rotor (described later) is protruded through the through hole (116a) centrally formed at the second housing (118).

Referring to FIG.10, one to three pins (117) are arranged about the through hole (116a) of the floor plate (116) at the second housing (118). Each pin (117) arranged on the floor plate (116) of the second housing (118) is coupled to a reduction gear of the transmission unit (300), and each of the reduction gears is rotated at a predetermined position by the pin (117).

A distal end of the rotation shaft (132) illustrated in FIG.11 is rotatably coupled to a bearing (133) coupled to the first housing (112), and the other distal end opposite to the one distal end of the rotation shaft (132) is rotatably coupled to a bearing (135) coupled to the second housing (118).

Referring again to FIGS. 10 and 11, the hub unit (200) encompasses the traction motor (100) and is rotatably arranged relative to the fixing shaft (50). The hub unit (200) includes a first hub unit (225) and a second hub unit (240), where the first hub unit (225) includes a lateral wall (210) and a floor plate (220).

Referring to FIG.11 again, the transmission unit (300) functions to change the speed ratio between the rotation shaft (132) and the hub unit (200). For example, the transmission unit (300) changes the speed ratio of the hub unit (200) relative to the rotation shaft (132) to allow the hub unit (200) to rotate at a lower revolution than that of the rotation shaft (132).

The transmission unit (300) includes a first reduction gear (310), a second reduction gear (320) and a third reduction gear (330).

Although FIG.11 describes and explains that the transmission unit is a 1-shift transmission unit, the transmission unit may be 2-shift or 3-shift transmission unit.

The traction motor module according to the second exemplary embodiment of the present invention has an advantageous effect in that a strength reinforcement unit for preventing a fixing shaft and a housing from being damaged or separated is formed at a portion where the fixing shaft and the housing of a traction motor are inter-coupled, to thereby prevent the fixing shaft and the housing from being damaged or separated.

THIRD EXEMPLARY EMBODIMENT

FIG.16 is a partially cut perspective view illustrating a traction motor module according to a third exemplary embodiment of the present invention, FIG.17 is an exploded perspective view illustrating a traction motor of FIG.16, FIG.18 is a perspective view illustrating a rear surface of the traction motor of FIG.17, and

FIG.19 is an exploded perspective view illustrating a traction motor module of FIG.16.

Referring to FIGS. 16 to 19, the traction motor module (1000) includes a fixing shaft (50), a traction motor (100), a hub unit (200) and a transmission unit (300).

Referring to FIG. 17, the traction motor (100) includes a housing (110), a stator (120) and a rotor (130). The housing (110) includes a first housing (112) and a second housing (118), where the second housing (118) is fastened to the first housing (112) by way of a fastening screw or the like.

The first housing (112) includes a disc-shaped first through hole (111) at a rotational center thereof, and three second through holes (111a) are formed about the first through hole (111) of the first housing (112), for example. Part of the second through holes (111a) arranged about the first through hole (111) are extended toward the first through hole (111), whereby each of the first and second through holes (111, 111a) takes the shape of a letter "T" when viewed on a plan, whereby the first and second through holes (111, 111a) are intercommunicated.

The first housing (112) is arranged at an inner lateral surface thereof with a doughnut-shaped circuit substrate (113), where the circuit substrate (113) is formed with a through hole corresponding to the hollow hole (52) of the fixing shaft (50).The circuit substrate (113) is arranged with a revolution count sensor (113a) for detecting a revolution count and/or revolution speed of a rotor (described later), as shown in FIG.19.

The second housing (118) takes the shape of an upper surface-opened cylinder. The second housing (118) includes a lateral wall (114), and a floor plate (116) blocking a floor of the lateral wall (114). The lateral wall (114) and the floor plate (116) may be integrally formed in the third exemplary embodiment of the present invention, for example.

Referring to FIGS.16 through 19 again, at least one, preferably, three transmission gear pins (117) are arranged about the through hole (116a) of the floor plate (116) at the second housing (118). Each pin (117) arranged on the floor plate (116) of the second housing (118) is coupled with a reduction gear of the transmission unit (300), and each of the reduction gears is rotated at a predetermined position by the transmission gear pins (117).

FIG.20 is a partially enlarged view of 'C' part of FIG.19.

Referring to FIG.20, in order to couple the transmission gear pins (117) for rotating the reduction gears by being coupled to the reduction gears to the floor plate (116) of the second housing (118), the floor plate (116) of the second housing (118) is formed with pin holes (118a) whose number is the same as that of the transmission gear pin (117). In the present exemplary embodiment, each pin hole (118a) formed on the floor plate (116) of the second housing (118) is formed with a diameter of D1.

Each transmission gear pin (117) inserted into each pin hole (118a) includes a fixing unit (117a) and a transmission gear coupling unit (117b). The fixing units (117a) and the transmission gear coupling units (117b) may be integrally formed, for example. Alternatively, the fixing units (117a) and the transmission gear coupling units (117b) may be assembled together using a fastening screw or the like.

The fixing unit (117a) is formed with a diameter suitable for being press-fitted into the pin hole (118a).

Meanwhile, in a case the fixing unit (117a) is protruded from an inner lateral surface of the floor plate (116) of the second housing (118), there is a high likelihood of the fixing unit (117a) mutually contacting the stator (120) of the housing (110), and in order to prevent the mutual contact therebetween, there is a need to fully distance the fixing unit (117a) from the stator (120). In this case, there may arise a problem of increasing the size of the traction motor (100), such that a distal end of the stator (120) is preferably arranged on the same planar surface as that of the inner lateral surface of the floor plate (116) of the second housing (118).

The transmission gear coupling unit (117b) is formed with a diameter (D2) greater than that (D1) of the pin hole (118a). That is, a sill is formed at a border between the transmission gear coupling unit (117b) and the fixing unit (117a) due to a difference between the two different diameters, and the sill serves as a stopper to prevent the fixing unit (117a) from protruding from the floor plate (116) of the second housing (118).

Meanwhile, in a case the floor plate (116) of the second housing (118) is thick, and an excessive tension is applied to the fixing unit (117a) of the transmission gear pin (117), there may arise a problem that the fixing unit (117a) of the transmission gear pin (117)is separated from the pin hole (118a).

In the present exemplary embodiment, in order to prevent the fixing unit (117a) of the transmission gear pin (117) from being separated from the pin hole (118a), a bushing unit (118b) may be formed about the pin hole (118a) in the periphery of the floor plate (116) of the second housing (118) to increase the coupling strength of the fixing unit (117a).

An insulation sheet (118c) may be arranged at the inner lateral surface of the floor plate (116) of the second housing to prevent the transmission gear pin (117) from electrically contacting the stator (120).

Referring to FIGS. 17 and 19 again, the stator (120) is arranged in an accommodating space formed by the lateral wall (114) of the second housing (118) and the floor plate (116), and fixed inside the housing (110) fixed to the fixing shaft (50).

In the present embodiment, the stator (120) includes a plurality of stator blocks (126), where the stator (120) may include 12 stator blocks (126), for example.

The stator (120) shaped in a ring by the assembled 12 stator blocks (126) is fixed inside the accommodation space of the second housing (118) at the housing (110).

In the third exemplary embodiment, due to the fact that the stator (120) shaped in a ring by the assembled 12 stator blocks (126) is arranged in the accommodation space of the second housing (118), a much larger number of stator blocks, e.g., 12, can be arranged inside the second housing (118) over a conventional arrangement of stator in the fixing shaft (50).

The rotor (130) includes a rotation shaft (132), a rotor core (134) and a magnet (136). In addition, the rotor (130) may further include a yoke (138) and a magnet sensor (139).

Referring again to FIG.19, the one distal end of the rotation shaft (132) is rotatably fixed by a bearing (133) arranged on the first housing (112), and the other distal end of the rotation shaft (132) is rotatably fixed by a bearing (135) coupled to an inner lateral surface of the burring unit (116b) formed on the floor plate (116) of the second housing (112).

The rotor core (134) takes the shape of a pipe having a hollow hole. The rotor core (134) is manufactured with a material suitable for passing a magnet flux generated by the magnet (136) without any loss.

Alternatively, the rotor core (134) may take the shape of a curved plate, in a case the through hole (137) of the rotor core (134) takes the shape of a curve, when viewed on a plan.

The magnet sensor (139) is arranged on the yoke (138) and takes the shape of a doughnut. As shown in FIG.17, the magnet sensor (139) is formed on a position corresponding to that of a magnet sensor (139a) of the circuit substrate (113).

Referring to FIGS. 16 and 19 again, the hub unit (200) encompasses the traction motor (100) to be rotatably arranged relative to the rotation shaft (50). The hub unit (200) includes a first hub unit (225) and a second hub unit (240), where the first hub unit (225) includes a lateral wall (210) and a floor plate (220).

Referring to FIGS. 16 and 19 again, the transmission unit (300) functions to change a speed ratio between the rotation shaft (132) and the hub unit (200). For example, the transmission unit (300) changes the revolution count of the hub unit (200) relative to the rotation shaft (132) such that the hub unit (200) can rotate at a revolution lower than that of the rotation shaft (132). The transmission unit (300) includes a first reduction gear (310), a second reduction gear (320) and a third reduction gear (330).

FIG.21 is a cross-sectional view illustrating a traction motor module according to another exemplary embodiment of the present invention, and FIG.22 is a partially enlarged view of 'D' part of FIG.21.

The traction motor module according to another exemplary embodiment of the present invention has substantially the same structure as that shown in FIGS. 19 and 20 except for the pin hole and the transmission gear pin. Therefore, like numbers refer to like elements throughout and explanations that duplicate one another will be omitted.

Referring to FIGS. 21 and 22, the traction motor module (1000) includes a fixing shaft (50), a traction motor (100), a hub unit (200) and a transmission unit (300).

The floor plate (116) of the second housing (118) of the housing (110) at the traction motor (100) is formed with pin holes (118d) for coupling to three transmission gear pins (119), where each pin hole is formed with a diameter of D3.

Each transmission gear pin (119) formed at each pin hole (118d) includes a fixing unit (119a) and a transmission gear coupling unit (119b). The fixing units (119a) of the transmission gear pin (119) and the transmission gear coupling units (119b) may be integrally formed, for example. Alternatively, the fixing units (119a) of the transmission gear pin (119) and the transmission gear coupling units (119b) may be assembled respectively.

The fixing unit (119a) of the transmission gear pin (119) is formed with a diameter suitable for being press-fitted into the pin hole (118d), and the transmission gear coupling units (119b) is formed with a diameter (D4) smaller than that of the pin hole (118d).

Meanwhile, in a case the transmission gear coupling units (119b) is formed with a diameter smaller than that of the fixing unit (119a) in the present embodiment, the fixing unit (119a) can be prevented from being separated from the floor plate (116) of the second housing (118). In order to prevent a distal end of the fixing unit (119a) and the stator (120) from being electrically contacted, the distal end of the fixing unit (119a) is arranged on the same planar surface as the floor plate (116) of the second housing (118).

The traction motor module according to the third exemplary embodiment of the present invention has an advantageous effect of being manufactured in a compact manner by the fact that the pin hole is formed at the housing of the traction motor for arranging the transmission unit between the traction motor of the traction motor module and the hub unit, the transmission gear pin is inserted into the pin hole to couple the transmission gear unit to the transmission gear pin, and the transmission unit is arranged inside the traction motor module.

FOURTH EXEMPLARY EMBODIMENT

FIG.23 is a partially cut perspective view illustrating a traction motor module according to a fourth exemplary embodiment of the present invention, FIG.24 is a partially cut perspective view illustrating a traction motor module of FIG.23, and

FIG.25 is a cross-sectional view illustrating a traction motor module of FIG.23.

Referring to FIGS. 23, 24 and 25, the traction motor module (1000) includes a fixing shaft (50), a traction motor (100), a hub unit (200), a transmission unit (300, see FIG.24), a motor bearing (400) and a hub bearing (500).

The fixing shaft (50) takes the shape of a metal pipe having a hollow hole (52) as shown in FIG.2, for example. The fixing shaft (50) may be connected to a frame for changing directions of a bicycle by being connected to a bicycle handle. A lateral surface of the fixing shaft (50) is formed with at least one through hole (54), and a distal end of the fixing shaft (50) is formed with a flange unit (56) bent outside relative to the fixing shaft (50). The fixing shaft (50) is inserted by a frame position determination washer (58), as illustrated in FIG. 25, which determines a position of the frame fixed to the fixing shaft (50).

The traction motor (100) includes a housing (110), a stator (120) and a rotor (130). The housing (110) includes a first housing (112) and a second housing (118).

The first housing (112) includes a disc-shaped first through hole (111, see FIG.24) at a rotational center thereof, and three second through holes (111a) are formed about the first through hole (111) of the first housing (112), for example. Part of the second through holes (111a) arranged about the first through hole (111) is extended toward the first through hole (111), whereby each of the first and second through holes (111, 111a) takes the shape of a letter "T" when viewed on a plan, whereby the first and second through holes (111, 111a) are intercommunicated.

A bottom surface opposite to the upper surface of the first housing (112) is formed with a bearing groove (112a) coupled to any one motor bearing in the motor bearings (described later), as shown in FIG.25.

The hollow hole (52) at the fixing shaft (50) is formed at a position corresponding to that of the first through hole (111) of the first housing (112), whereby the first through hole (111) and the hollow hole (52) are intercommunicated. The part extended to be connected to the first through hole (111) in the second through holes (111a) is covered by the flange unit (56). A space formed by the flange unit (56) and the part extended to be connected to the first through hole (111) in the second through holes (111a) is passed by a wiring for applying a driving signal to a coil wound on a stator core of a stator.

The second housing (118) takes the shape of an upper surface-opened cylinder. The second housing (118) includes a lateral wall (114), and a floor plate (116) connected to the lateral wall (114). The lateral wall (114) and the floor plate (116) may be integrally formed in the third exemplary embodiment of the present invention, for example.

The floor plate (116) of the second housing (118) is centrally formed with a burring unit (116b) formed with a through hole (116a).The through hole (116a) centrally formed at the second housing (118) is protruded with a rotation shaft of a rotor (described later), and the burring unit (116b) is coupled to a balanced motor bearing in the motor bearings (described later).

Referring to FIG. 23, one to three pins (117) are arranged about the through hole (116a) of the floor plate (116) at the second housing (118). Each pin (117) arranged on the floor plate (116) of the second housing (118) is coupled with a planetary gear (not shown) of the transmission unit (300), and the planetary gear is rotated by the pins (117). The second housing (118) is fastened to the first housing (112) by a fastening screw or the like.

Referring to FIG.23, the stator (120) is arranged in an accommodating space formed by the lateral wall (114) of the second housing (118) and the floor plate (116), and fixed inside the housing (110) fixed to the fixing shaft (50).

Each stator block (126) includes a stator core (122) and a coil (124).The stator core (122) takes the shape of a letter "H" when viewed on a plan, and is formed by laminating a plurality of thin "H" shaped steel pieces. The coil (124) is wound on a concave portion of the stator core (122) in the predetermined coil turns. The stator core (122) at each stator block (126) is made of insulation material, and may further include an insulation member insulating the stator core (122) and the coil (124) by being coupled to both distal ends of the stator core (122).

Each of the plurality of block-shaped stator blocks (126) is circularly assembled by way of press-fitting, including the coil (124) wound on the stator core (122), such that the stator (120) takes the shape of a ring when viewed on a plan.

The stator (120) shaped in a ring by the assembled 12 stator blocks (126) is fixed along an inner lateral surface of the second housing (118) at the housing (110).

In the fourth exemplary embodiment, due to the fact that the stator (120) shaped in a ring by the assembled 12 stator blocks (126) is arranged in the accommodation space of the second housing (118), a much larger number of stator blocks, e.g., 12, can be arranged inside the second housing (118) over a conventional arrangement of stator in the fixing shaft (50).

Referring to FIGS. 23 and 25, the rotor (130) includes a rotation shaft (132), a rotor core (134) and a magnet (136). In addition, the rotor (130) may further include a yoke (138) and a magnet sensor (139).

The other distal end of the rotation shaft (132) protruded from the floor plate (116) of the second housing (118) may be coupled to a sun gear (136) coupled to the transmission unit.

takes the shape of a curve, when viewed on a plan.

The magnet sensor (139) is arranged on the yoke (138) and takes the shape of a doughnut. As shown in FIG.24, the magnet sensor (139) is formed on a position corresponding to that of a magnet sensor (139a) of the circuit substrate (113).

Referring to FIGS. 24 and 25, the hub unit (200) encompasses the traction motor (100) and rotated by power outputted from the fixing shaft (50). The hub unit (200) includes a first hub unit (225) and a second hub unit (240), where the first hub unit (225) includes a lateral wall (210) and a floor plate (220).

The lateral wall (210) of the first hub unit (225) takes the shape of a cylinder, where the floor plate (220) is arranged on a distal end of the lateral wall (210). An inner circumferential surface of the lateral wall (210) is discrete from a lateral wall (114) of the second housing (118) at the traction motor (100) at a predetermined space to be prevented from being fractionized with the lateral wall (114) of the second housing (118), in a case the lateral wall (210) of the first hub unit (225) is rotated.

A floor plate (220) of the first hub unit (225) is formed with a bushing unit (227) discrete from a periphery of the fixing shaft (50).

The second hub unit (240) takes the shape of a plate, and is coupled to an opened distal end of the first hub unit (225). The first hub unit (225) and the second hub unit (240) are coupled by a fastening screw or the like.

The second hub unit (240) and a floor surface (116) of the second housing (118) at the housing (110) of the traction motor (100) are discrete from each other at a predetermined gap to form a space (260).

The transmission unit (300) rotates the hub unit (200), and functions to change a speed ratio between the rotation shaft (132) and the hub unit (200). For example, the transmission unit (300) changes the revolution count of the hub unit (200) relative to the rotation shaft (132) such that the hub unit (200) can rotate at a revolution lower than that of the rotation shaft (132). Referring to FIGS. 24 and 25, the transmission unit (300) includes a first reduction gear (310), a second reduction gear (320) and a third reduction gear (330).

The second tooth set (325) formed at the periphery of the second reduction gear (320) is meshed with the first tooth set (315) of the first reduction gear (310). The third reduction gear (330) is coupled to a rotation shaft (132) protruded from the floor plate (116) of the second housing (118), and may include a sun gear formed at a periphery with a third tooth set (335). The third tooth set (335) formed at the periphery of the third reduction gear (330) is meshed with the second tooth set (325) of the second reduction gear (320).

Referring to FIGS. 23 and 25 again, motor bearings (400) include a first motor bearing (410) and a second motor bearing (420). The motor bearings (400) rotate the rotation shaft (132) rotating at a high speed relative to the stator (120) with a smaller friction force and support the rotation shaft (132). The first motor bearing (410) is coupled to a bearing groove (112a) formed at the bottom surface of the first housing (112) at the housing (110), and is rotatably coupled with a distal end of the rotation shaft (132).

The second motor bearing (420) is coupled to the burring unit (116b) centrally formed at the second housing (118) of the housing (110), and is rotatably coupled to the other distal end opposite to the one distal end of the rotation shaft (132).

Hub bearings (500) include a first hub bearing (510) and a second hub bearing (520), and rotate the hub unit (200) rotated by power supplied from the transmission unit (300) with a smaller friction force and support the hub unit (200). The first hub bearing is interposed between a bushing unit (227) formed at a first hub unit (225) of the hub unit (200) and the fixing shaft (50) opposite to the bushing unit (225). The second hub bearing (520) is arranged on the second hub unit (240). The second hub bearing (520) may be coupled to an axis that is coupled to the third reduction gear (330) of the transmission unit (300).

The traction motor module according to the fourth exemplary embodiment of the present invention has an advantageous effect in that the motor bearings supporting the both distal ends of the rotation shaft are arranged on the housing of the traction motor, and hub bearings supporting the hub unit is arranged on the hub unit of the traction motor, whereby the hub unit and the rotation shaft of the traction motor rotating the hub units can be rotated with a smaller friction force, and an excessive stress can be prevented from being concentrated on the rotor or stator of the traction motor.

FIFTH EXEMPLARY EMBODIMENT

FIG.26 is a partially cut perspective view illustrating a traction motor module according to a fifth exemplary embodiment of the present invention, FIG.27 is a cross-sectional view illustrating a traction motor module of FIG.26, FIG.28 is an exploded perspective view illustrating a traction motor module of FIG.27, FIG.29 is an exploded perspective view illustrating a rotor and FIG.30 is a lateral view illustrating a rotation shaft of a rotor of FIG.27.

Referring to FIGS. 26 through 30, the traction motor module (1000) includes a fixing shaft (50), a traction motor (100), a hub unit (200) and a transmission unit (300).

The fixing shaft (50) takes the shape of a metal pipe having a hollow hole (52) as shown in FIG.27, for example. A lateral surface of the fixing shaft (50) is formed with at least one through hole (54), and a distal end of the fixing shaft (50) is formed with a flange unit (56) bent outside relative to the fixing shaft (50). The fixing shaft (50) is inserted by a frame position determination washer (58), which determines a position of the frame fixed to the fixing shaft (50).

The first housing (112) includes a disc-shaped first through hole (111, see FIG.24) at a rotational center thereof, and three second through holes (111a) are formed about the first through hole (111) of the first housing (112), for example. Part of the second through holes (111a) arranged about the first through hole (111) are extended toward the first through hole (111), whereby each of the first and second through holes (111, 111a) takes the shape of a letter "T" when viewed on a plan, whereby the first and second through holes (111, 111a) are intercommunicated.

The first housing (112) is arranged at an inner lateral surface thereof with a doughnut-shaped circuit substrate (113), where the circuit substrate (113) is formed with a through hole corresponding to the hollow hole (52) of the fixing shaft (50). The first housing (112) is arranged with a circular lug unit (112a) protruded from an inner lateral surface of the first housing (112) to secure a first bearing (133, described later).

The second housing (118) takes the shape of an upper surface-opened cylinder. The second housing (118) includes a lateral wall (114), and a floor plate (116) connected to the lateral wall (114). The lateral wall (114) and the floor plate (116) may be integrally formed in the fifth exemplary embodiment of the present invention, for example.

The floor plate (116) of the second housing (118) is centrally formed with a burring unit (116b) formed with a through hole (116a). The burring unit (116b) is circularly protruded from the inner lateral surface of the floor plate (116). Part of the rotation shaft (132) of the rotor (described later) is protruded from the through hole (116a) formed at the center of the second housing (118). The second housing (118) is coupled to the first housing by a fastening screw and the like. The second housing (118) and the first housing (112) are respectively arranged with a first bearing (133) and a second bearing (135). That is, the first housing (112) is arranged with the first bearing (133), and the second housing (118) is arranged with the second bearing (135). The first bearing (133) is secured to the circular lug unit (112a) of the first housing (112), and the second bearing (135) is secured to the circularly protruded burring unit (116b).

Now, referring to FIGS. 26 and 27 again, the stator (120) is arranged in an accommodating space formed by the lateral wall (114) of the second housing (118) and the floor plate (116), and fixed inside the housing (110) fixed to the fixing shaft (50).

Each stator block (126) includes a stator core (122) and a coil (124).The stator core (122) takes the shape of a letter "H" when viewed on a plan, and is formed by laminating a plurality of thin "H" shaped steel pieces. The coil (124) is wound on a concave portion of the stator core (122) in the predetermined coil turns. The stator core (122) at each stator block (126) and the coil (124) are insulated from each other by an insulation material (not shown).

In the fifth exemplary embodiment, due to the fact that the stator (120) formed by assembling the stator blocks (126) is arranged in the accommodation space of the second housing (118), a much larger number of stator blocks, e.g., 12, can be arranged inside the second housing (118) over a conventional arrangement of stator in the fixing shaft.

Particularly, due to the fact that the stator blocks are manufactured by winding the coil (124) on each stator core (122), and the stator (120) is manufactured by assembly of manufactured stator blocks (126), the stator (120) having more stator blocks on a limited unit area can be realized. Meanwhile, the stator core (122) with tightly wound coil (124) cannot be implemented from the conventional structure where a coil is wound on an integrated stator core.

Referring to FIGS.29 and 30, the rotor (130) includes a rotation shaft (132), a rotor core (134) and a magnet (136).

The rotation shaft support units (134a) protruded from the inner lateral surface of the rotor core (134) are formed toward the interior of the rotor core (134) from the both distal ends of rotor core (134) each spaced at a predetermined distance.

The rotor core (134) may include through holes (137) that pass the upper surface of the rotor core (134) and the bottom surface opposite to the upper surface, where the rotor core (134) may be formed with eight through holes (137), for example.

The magnet (136) takes the shape of a rectangle or curved plate corresponding to that of the through hole (137). In other words, magnet (136) takes the shape corresponding to that of the through hole (137). For example, in a case the through hole (137) takes the shape of a rectangle when viewed on a plan, the magnet (136) takes the plated shape of a rectangular parallelepiped. Alternatively, the rotor core (134) may take the shape of a curved plate, in a case the through hole (137) of the rotor core (134) takes the shape of a curve, when viewed on a plan.

A yoke (138) formed with a yoke burring unit (138a) is arranged on the upper surface opposite to the first housing (112), and a doughnut-shaped magnet sensor (139) is formed on the upper surface of the yoke (138).

Referring to FIG.30, the rotation shaft (132) takes the shape of a circular cylinder with different diameters (described later), for example. The rotation shaft (132) includes a first bearing coupling unit (132a), a yoke coupling unit (132b), a rotor coupling unit (132c), a second bearing coupling unit (132d) and a transmission gear unit (132e).

The first bearing coupling unit (132a) is formed with a first diameter, the yoke coupling unit (132b) is formed with a second diameter greater than the first diameter, the rotor coupling unit (132c) is formed with a third diameter greater than the second diameter, the second bearing coupling unit (132d) is formed with a fourth diameter greater than the third diameter and the transmission gear unit (132e) is formed with a fifth diameter greater than the fourth diameter. In the present embodiment, the first through fifth diameters increase intermittently.

The first bearing coupling unit (132a) of the rotation shaft (132) is press-fitted by a first bearing (133) coupled to the first housing (112) illustrated in FIG.2.

The yoke coupling unit (132b) of the rotation shaft (132) is formed with the yoke burring unit (138a) of the yoke (138) arranged on the upper surface of the rotor core (134). The yoke coupling unit (132b) is superficially formed thereon with a yoke rotation prevention unit (132f) preventing the yoke burring unit (138a) and the yoke coupling unit (132b) of the rotation shaft (132) from rotatably slipping to thereby improve the rotation-resistant force of the yoke (138).

A plurality of yoke rotation prevention units (132f) may be formed along the periphery of the yoke burring unit (138a), and each yoke rotation prevention unit (132f) may take the shape of a concave formed in the lengthwise direction or a groove. The rotor coupling unit (132c) is coupled by the rotation shaft support unit (134a) of the rotor core (134), and is coupled to a rotation shaft hole of the rotation shaft support unit (134a).

The rotor coupling unit (132c) is superficially formed with a rotor core rotation prevention unit (132g) preventing the rotation shaft support unit (134a) of the rotor core (134) and the rotor coupling unit (132c) from slipping. A plurality of rotor core rotation prevention units (132g) may be formed along the periphery of the rotor coupling unit (132c), for example, and each rotor core rotation prevention unit (132g) may take the shape of a concave formed in the lengthwise direction or a groove.

The second bearing coupling unit (132d) is press-fitted by a second bearing (135) coupled to the burring unit (116b) of the second housing (118).

The transmission gear unit (132e) is arranged on a distal end of the rotation shaft (132) protruded from the second housing (118), and is formed at a lateral surface thereof with a transmission tooth set. In the present embodiment, the transmission gear unit (132e) takes the shape similar to that of a sun gear.

Referring to FIGS. 2 and 4, due to the fact that the first bearing coupling unit (132a), the yoke coupling unit (132b), the rotor coupling unit (132c), the second bearing coupling unit (132d) and the transmission gear unit (132e) are formed with intermittently increasing first to fifth diameters, the first bearing coupling unit (132a), the yoke coupling unit (132b), the rotor coupling unit (132c), the second bearing coupling unit (132d) and the transmission gear unit (132e) can be sequentially assembled with the first bearing (135), the yoke (138), the rotor core (134) and the second bearing (135), whereby the assembly process can be efficiently performed.

Referring to FIGS. 26 and 27 again, the hub unit (200) encompasses the traction motor (100) and is rotatably arranged relative to the fixing shaft (50). The hub unit (200) includes a first hub unit (225) and a second hub unit (240), where the first hub unit (225) includes a lateral wall (210) and a floor plate (220).

A floor plate (220) of the first hub unit (225) is formed with a bushing unit (227) discrete from a periphery of the fixing shaft (50). A bearing (228) is interposed between the bushing unit (227) and the periphery of the fixing shaft (50) to allow the first hub unit (225) to rotate relative to the fixing shaft (50).

To be more specific, the space (260) is formed between the floor surface (116) of the second housing (118) and the second hub unit (240) suitable for mounting the transmission unit (300) for rotating the hub unit (200) at a revolution lower than that of the rotation shaft (132) of the traction motor (100), and the floor surface (116) of the second housing (118) for mounting the transmission unit is formed with the pin (117) mounted with the planetary gear for rotating the planetary gear included in the transmission unit (300), as illustrated in FIG.26. Meanwhile, a bearing (250) rotatably fixing the rotation shaft (132) may be arranged at a position corresponding to the distal end of the rotation shaft (132) in the second hub unit (240).

Referring to FIGS. 26 and 27 again, the transmission unit (300) functions to change a speed ratio between the rotation shaft (132) and the hub unit (200). For example, the transmission unit (300) changes the revolution count of the hub unit (200) relative to the rotation shaft (132) such that the hub unit (200) can rotate at a revolution lower than that of the rotation shaft (132).

The transmission unit (300) includes a ring gear (310), a planetary gear (320).

The ring gear (310) takes the shape of a ring along an inner lateral surface of the lateral wall (210) of the first hub unit (225) at the hub unit (200), and is formed with a tooth set. The planetary (320) is rotatably fixed at a pin (117) arranged on the floor plate (116) of the second housing (118) at the housing (110) of the traction motor (100), and is formed at a periphery with a tooth set. In the present exemplary embodiment, the pin (117) is circularly arranged at a 120-degree on the floor plate (116), such that three planetary gears (320) are arranged on the floor plate (116).

The tooth set formed at the periphery of the planetary gear (320) is meshed with the tooth set of the transmission gear unit (132e). In the present embodiment, the tooth set of the transmission gear unit of the rotation shaft (132) is formed with a first number of tooth sets, the tooth set of the planetary gear (320) is formed with a second number of tooth sets greater than the first number of tooth sets, and the tooth set of the ring gear (310) is formed with a third number of tooth sets greater than the second number of tooth sets.

Therefore, the planetary gear (320) is rotated at a revolution lower than that of the rotation shaft (132), as the transmission gear unit (132e) rotating at the same revolution as that of the rotation shaft (1321) is rotated, and the ring gear (310) is rotated at a revolution lower than that of the planetary gear (320) as the planetary gear (320) is rotated. Therefore, the hub unit (200) coupled to the ring gear (310) is rotated at a revolution much lower than that of the rotation shaft (132), whereby a user can travel at a stable speed.

The traction motor module according to the fifth exemplary embodiment of the present invention has an advantageous effect in that diameters of rotation shaft at the rotor are intermittently increased to sequentially couple the bearing, the yoke, the rotor core to the rotation shaft, and the transmission gear unit which is a part of the transmission unit is integrally formed at the distal end of the rotor. whereby the weight and size of the traction motor can be compactly reduced.

SIXTH EXEMPLARY EMBODIMENT

FIG.31 is a partially cut perspective view illustrating a traction motor module according to a sixth exemplary embodiment of the present invention, FIG.32 is a cross-sectional view illustrating a traction motor module of FIG.32, and FIG.33 is a partially enlarged view of 'E' part of FIG.32.

Referring to FIGS. 31, 32 and 33, the traction motor module (1000) includes a fixing shaft (50), a traction motor (100), a hub unit (200) and a transmission unit (300).

The fixing shaft (50) takes the shape of a metal pipe having a hollow hole (52) as shown in FIG.32, for example.

The fixing shaft (50) may be connected to a frame for changing directions of a bicycle by being connected to a bicycle handle. A lateral surface of the fixing shaft (50) is formed with at least one through hole (54), and a distal end of the fixing shaft (50) is formed with a flange unit (56) bent outside relative to the fixing shaft (50). The fixing shaft (50) is inserted by a frame position determination washer (58), which determines a position of the frame fixed to the fixing shaft (50).

The first housing (112) includes a disc-shaped first through hole (111) at a rotational center thereof, and three second through holes (111a) are formed about the first through hole (111) of the first housing (112), for example. Part of the second through holes (111a) arranged about the first through hole (111) is extended toward the first through hole (111), whereby each of the first and second through holes (111, 111a) takes the shape of a letter "T" when viewed on a plan, whereby the first and second through holes (111, 111a) are intercommunicated.

The first housing (112) is arranged at an inner lateral surface thereof with a doughnut-shaped circuit substrate (113), where the circuit substrate (113) is formed with a through hole corresponding to the hollow hole (52) of the fixing shaft (50).The first housing (112) is arranged with a circular lug unit (112a) protruded from an inner lateral surface of the first housing (112) for securing the first bearing (described later).

The second housing (118) takes the shape of an upper surface-opened cylinder. The second housing (118) includes a lateral wall (114), and a floor plate (116) blocking a floor of the lateral wall (114). The lateral wall (114) and the floor plate (116) may be integrally formed in the sixth exemplary embodiment of the present invention, for example.

The floor plate (116) of the second housing (118) is centrally formed with a burring unit (116b) formed with a through hole (116a). The burring unit (116b) is circularly protruded from the inner lateral surface of the floor plate (116).The through hole (116a) centrally formed at the second housing (118) is protruded with a rotation shaft of a rotor (described later). The second housing (118) is coupled to the first housing (112) via a fastening screw or the like. The second housing (118) and the first housing (112) are respectively formed with a first bearing (133) and a second bearing (135). The first housing (112) is arranged with the first bearing (133) and the second housing (118) is arranged with the second bearing (135). The first bearing (133) is secured to the circular lug unit (112a) of the first housing (112), and the second bearing (135) is secured to the circularly protruded burring unit (116b).

Referring to FIGS.31 and 32, the stator (120) is arranged in an accommodating space formed by the lateral wall (114) of the second housing (118) and the floor plate (116), and fixed to the inner lateral surface of the lateral wall (114) of the second housing (118) at the housing (110) fixed to the fixing shaft (50).

In the present sixth embodiment, the stator (120) includes a plurality of stator blocks (126), where the stator (120) may include 12 stator blocks (126), for example, and each stator block takes the shape of a block of a rectangular parallelepiped.

Each stator block (126) includes a stator core (122) and a coil (124).The stator core (122) takes the shape of a letter "H" when viewed on a plan, and is formed by laminating a plurality of thin "H" shaped steel pieces. The coil (124) is wound on a concave portion of the stator core (122) in the predetermined coil turns. The stator core (122) at each stator block (126) and the coil (124) are made of insulation material (not shown).

The stator (120) shaped in a ring by the 12 assembled stator blocks (126) is fixed at the accommodating space of the second housing (118) of the housing (110).

In the sixth exemplary embodiment, due to the fact that the stator (120) shaped in a ring by the 12 assembled stator blocks (126) is arranged in the accommodation space of the second housing (118), a much larger number of stator blocks, e.g., 12, can be arranged inside the second housing (118) over a conventional arrangement of stator in the fixing shaft (50).

FIG.34 is an exploded perspective view illustrating a rotor of FIG.32.

Referring to FIGS. 32 and 34, the rotor (130) includes a rotation shaft (132), a rotor core (134) and a magnet (136). The rotation shaft (132) is arranged in a hollow hole formed by the stator (120) arranged along an inner lateral surface of the second housing (118) at the housing (110). A gap is formed between a periphery of the rotation shaft (132) and an inner circumferential surface of the stator (120), and the rotation shaft (132) is centrally arranged in the stator (120).

One distal end of the rotation shaft (132) is rotatably coupled to the first bearing (133) of the first housing (112), and the other distal end opposite to the one distal end of the rotation shaft (132) is coupled to the second bearing (135) coupled to the burring unit (116b) of the floor plate (116) of the second housing (118), and the other distal end is protruded toward the outside through the through hole (116a).

The other distal end of the rotation shaft (132) is rotatably secured by the bearing (133) arranged on the first housing (112) as shown in FIG.2, and the other distal end opposite to the one distal end of the rotation shaft (132) is rotatably secured by the bearing (135) coupled to the inner lateral surface of the burring unit (116b) formed at the floor plate (116) of the second housing (118).

A plurality of rotation shaft support units (134a), e.g., four units, may be protruded from an inner lateral surface of the rotor core (134) formed by the hollow hole of the rotor core (134) toward the center of the rotor core (134). The four rotation shaft support units (134a) protruded from the inner lateral surface of the rotor core (134) are connected to a center of the rotor core (134) to form a rotation shaft hole press-fitted by the rotation shaft (132).

The rotation shaft support units (134a) protruded from the inner lateral surface of the rotor core (134) are formed at a position discrete inward of the rotor core (134) from both distal ends of the rotor core (134).

The rotor core (134) may include through holes (137) that pass an upper surface of the rotor core (134) and a bottom surface of the rotor core (134). The rotor core (134) may be formed with eight through holes (137), for example.

The magnet (136) takes the shape of a rectangular parallelepiped or a a curve corresponding to that of through hole (137) of the rotor core (134). The magnet (136) takes the shape corresponding to that of the through hole (137). For example, in a case the through hole (137) takes the shape of a rectangle when viewed on a plan, the magnet (136) takes the plated shape of a rectangular parallelepiped. Alternatively, the rotor core (134) may take the shape of a curved plate.

In the present embodiment the weight and volume of the traction motor can be reduced by using the hollow hole of the rotor core (134), in a case the hollow hole is formed inside the rotor core (134), and the rotor core (134) is secured at the rotation shaft (132) using the rotation shaft support unit (134a).

To be more specific, the hollow hole of the rotor core (134) of the rotor (130) is inserted by at least part of the first bearing (133) fixed at the first housing (112) as long as the length of D1, as shown in FIG.3, and is inserted by at least part of the second bearing (135) secured at the second housing (118) as long as the length of D2, as shown in FIG.3, whereby the size of the second housing (118) of the traction motor (100) can be reduced as much as the lengths of D1 and D2. Alternatively, the first and second bearings (133, 135) may be inserted into the hollow hole of the rotor core (134) at full lengths. In the present embodiment, the first and second bearings (133, 135), and the rotation shaft support unit (134a) inside the rotor core (134) may be discrete from each other at a predetermined space.

Referring to FIGS. 31 and 32, the hub unit (200) encompasses the traction motor (100) and is rotatably arranged relative to the fixing shaft (50). The hub unit (200) includes a first hub unit (225) and a second hub unit (240), where the first hub unit (225) includes a lateral wall (210) and a floor plate (220).

A floor plate (220) of the first hub unit (225) is formed with a bushing unit (227) discrete from a periphery of the fixing shaft (50). A bearing (228) is arranged between the bushing unit (227) and the periphery of the fixing shaft (50) to allow the first hub unit (225) to rotate relative to the fixing shaft (50).

To be more specific, the space (260) is formed between the floor surface (116) of the second housing (118) and the second hub unit (240) suitable for mounting the transmission unit (300) for rotating the hub unit (200) at a revolution lower than that of the rotation shaft (132) of the traction motor (100), and the floor surface (116) of the second housing (118) for mounting the transmission unit is formed with the pin (117) mounted with the planetary gear for rotating the planetary gear. Meanwhile, a bearing (250) rotatably fixing the rotation shaft (132) may be arranged at a position corresponding to the distal end of the rotation shaft (132) in the second hub unit (240).

Referring to FIGS. 31 and 32, the transmission unit (300) functions to change a speed ratio between the rotation shaft (132) and the hub unit (200). For example, the transmission unit (300) changes the revolution count of the hub unit (200) relative to the rotation shaft (132) such that the hub unit (200) can rotate at a revolution lower than that of the rotation shaft (132).

FIG.35 is a cross-sectional view illustrating a traction motor module according to another exemplary embodiment of the present invention, FIG.36 is an exploded perspective view illustrating a rotor of FIG.35, and FIG.37 is an enlarged view illustrating 'F' part of FIG.35.

The traction motor module according to another exemplary embodiment of the present invention has the substantially same structure as that illustrated in FIGS. 31 through 34 except for a yoke and revolution count detecting sensor, such that like numbers refer to like elements throughout and explanations that duplicate one another will be omitted.

Referring to FIGS.35, 36 and 37, the traction motor module (1000) includes a fixing shaft (50), a traction motor (100), a hub unit (200) and a transmission unit (300).

The rotor (130) of the traction motor (100) includes a rotation shaft (132), a rotor core (134), a magnet (136), a yoke (138) and a magnet sensor (139).

The yoke (138) is arranged on an upper surface opposite to the first housing (112) in the rotor core (134), and includes a disc-shaped yoke body (138a) centrally formed with an opening, and a yoke burring unit (138b) protruded from the opening of the yoke body (138a).

At least part of the yoke burring unit (138b) is arranged inside the hollow hole of the rotor core (134) to thereby reduce the size of the traction motor (100). In the present embodiment, the yoke burring unit (138b) is inserted into the hollow hole of the rotor core (134) as long as the length of D3, as depicted in FIG.37.

Meanwhile, the second bearing (135) coupled to the burring unit (116b) of the second housing (118) of the housing (110) is inserted into the hollow hole of the rotor core (134) as long as the length of D4, as illustrated in FIG.37.

The traction motor module according to the sixth exemplary embodiment of the present invention has an advantageous effect in that a hollow hole is formed at the rotor core of the rotor, and part of the bearing coupled to the rotation shaft is arranged in the hollow hole of the rotor core, whereby the size of the traction motor can be compactly formed to reduce the overall volume and weight of the traction motor module and to thereby improve the energy use efficiency.

SEVENTH EXEMPLARY EMBODIMENT

FIG.38 is a partially cut perspective view illustrating a traction motor module according to a seventh exemplary embodiment of the present invention, FIG.39 is a cross-sectional view illustrating a traction motor module of FIG.28, and FIG.40 is an exploded perspective view illustrating a second housing and a stator of FIG.39.

Referring to FIGS. 38 through 40, the traction motor module (1000) includes a fixing shaft (50), a traction motor (100), a hub unit (200) and a transmission unit (300).

The fixing shaft (50) takes the shape of a metal pipe having a hollow hole (52) as shown in FIG.39, and is connected to a frame for changing directions of wheels of bicycle by being connected to a handle of the bicycle. The fixing shaft (50) is formed with one through hole (54) for connecting inside and outside of the fixing shaft (50), and a distal end of the fixing shaft (50) is formed with a flange unit (56) bent outside relative to the fixing shaft (50). The fixing shaft (50) is inserted by a frame position determination washer (58), which determines a position of the frame fixed to the fixing shaft (50).

The first housing (112) takes the shape of a disc, for example, and includes a first through hole (111) at a rotational center thereof, as illustrated in FIG.2, and three second through holes (111a) are formed about the first through hole (111) of the first housing (112). Part of the second through holes (111a) arranged about the first through hole (111) is extended toward the first through hole (111), whereby each of the second through holes (111a) takes the shape of a letter "T" when viewed on a plan. In the present embodiment, the first and second through holes (111, 111a) are intercommunicated.

The first housing (112) is arranged at an inner lateral surface thereof with a doughnut-shaped circuit substrate (113), where the circuit substrate (113) is formed with a through hole corresponding to the hollow hole (52) of the fixing shaft (50). The circuit substrate (113) is arranged with a revolution count sensor (113a) for detecting the revolution and/or the rotation speed of the rotor (described later), as shown in FIG.2.

Referring to FIG. 3, the second housing (118) takes the shape of an upper surface-opened cylinder. The second housing (118) includes a lateral wall (114), and a floor plate (116) connected to the lateral wall (114). The second housing (118) is fastened to the first housing (112) by a fastening screw or the like. The lateral wall (114) of the second housing (118) and the floor plate (116) may be integrally formed, for example.

The floor plate (116) of the second housing (118) is centrally formed with a burring unit (116b) formed with a through hole (116a). The rotation shaft of the rotor (described later) is protruded from the through hole (116a) formed at the center of the second housing (118). The inner lateral surface of the lateral wall (114) of the second housing (118) includes a first fixing unit (114a) into which an external surface of the rotor (described later) is fit-pressed, and a second fixing unit (114b) for supporting the distal end of the stator (120).

The lateral wall (114) corresponding to the first fixing unit (114a) of the second housing (118) is formed with a first thickness (T1), and the lateral wall (114) corresponding to the second fixing unit (114b) of the second housing (118) is formed with a second thickness (T2) thicker than the first thickness (T1). In the present embodiment, the first fixing unit (114a) and the second fixing unit (114b) are interconnected.

That is, an inner lateral surface corresponding to the first fixing unit (114a) of the second housing (118) is formed with a first thickness, while an inner lateral surface corresponding to the second fixing unit (114b) of the second housing (118) is formed with a second thickness which is thinner than the first thickness.

In a case the lateral wall (114) corresponding to the first fixing unit (114a) of the second housing (118) is formed with a first thickness (T1), and the lateral wall (114) corresponding to the second fixing unit (114b) of the second housing (118) is formed with a second thickness (T2) which is thicker than the first thickness (T1), a sill (114c) is formed at a border between the first fixing unit (114a) and the second fixing unit (114b) due to thickness difference of the first fixing unit (114a) and the second fixing unit (114b).

A distal end of the stator (120, described later) is supported by the sill (114c), whereby the stator (120) is restricted in the axial direction of the rotation shaft (described later), whereby the stator (120) and the floor plate (116) of the second housing (118) are prevented from being electrically contacted.

The second housing (118) is heated at a high temperature for coupling the stator (120) into the second housing (118) having the first and second fixing units (114a, 114b), and the second housing (118) is expanded in volume thereof by the thermal expansion, and cooled after being inserted into the stator (120), whereby the stator (120) is secured inside the second housing (118).

FIG.41 is a plan view illustrating a second housing and a stator according to another exemplary embodiment of the present invention.

Referring to FIG. 41, a rotation prevention unit (118a) is formed at the first fixing unit (114a) in the inner lateral surface of the second housing (118), and a rotation prevention groove (125) is formed at an outer lateral surface of the stator (120) corresponding to the rotation prevention unit (118a) of the second housing (118).

In the present embodiment, the rotation prevention unit (118a) formed at the first fixing unit (114a) is a lug formed from an upper end of the lateral wall (114) of the second housing (118) to the second fixing unit (114b), and takes the shape of a rib or a lug.

The rotation prevention groove (125) is formed at an outer lateral surface of the stator (120) has a size suitable for being coupled to the rotation prevention unit (118a) formed at the first fixing unit (114a), and takes the shape of a groove.

In the present embodiment, at least two rotation prevention units (118a) formed at the first fixing unit (114a) may be formed in parallel at an area corresponding to the first fixing unit (114a) in the inner lateral surface of the second housing (118).

In the present embodiment, the rotation prevention unit (118a) formed at the first fixing unit (114a) and the rotation prevention groove (125) is formed at an outer lateral surface of the stator (120) are coupled by press-fitting method, such that even if the rotor (described later) is rotated at a high speed or the housing (110) including the second housing (118) is heated at a high temperature, the stator (120) is prevented from rotating relative to the rotor.

Although the present embodiment has illustrated and explained a technical feature in which the rotation prevention unit (118a) and the rotation prevention groove (125) are formed at the inner lateral surface of the stator (120) press-fitted with the first fixing unit (114a) and the rotation prevention groove (125), the invention is not limited thereto. Alternatively, at least two grooves or lugs may be formed at a surface of the second fixing unit (114b) opposite to the distal end of the stator (120), grooves and lugs coupled to the grooves and the lugs may be formed at the distal end of the stator (120), and the stator (120) may be coupled to the second fixing unit (114b) to prevent the stator (120) from rotating relative to the rotor.

Furthermore, although the present embodiment has illustrated and explained a technical feature in which the linear rib-shaped rotation prevention unit (118a) is formed at the first fixing unit (114a), and the linear rib-shaped rotation prevention groove (125) is formed at the stator (120), the invention is not limited thereto. Alternatively, the rotation prevention unit (118a) may be formed at the first fixing unit (114a) in a screw shape or a diagonal line shape.

FIG.42 is a plan view illustrating a second housing and a stator according to still another exemplary embodiment of the present invention.

Referring to FIG.42, a rotation prevention groove (118b) is formed at the first fixing unit (114a) in the inner lateral surface of the second housing (118), and a rotation prevention unit (127) is formed at an outer lateral surface of the stator (120) corresponding to the rotation prevention groove (118b) of the second housing (118).

In the present embodiment, the rotation prevention groove (118b) formed at the first fixing unit (114a) is a lug formed from an upper end of the lateral wall (114) of the second housing (118) to the second fixing unit (114b), and takes the shape of a groove.

A rotation prevention unit (127) formed at an outer lateral surface of the stator (120) has a size suitable for being coupled to the rotation prevention groove (118b) formed at the first fixing unit (114a), and takes the shape of a rib or a lug.

In the present embodiment, at least two rotation prevention grooves (118b) formed at the first fixing unit (114a) may be formed in parallel at an area corresponding to the first fixing unit (114a) in the inner lateral surface of the second housing (118).

In the present embodiment, the rotation prevention groove (118ba) formed at first and second fixing units (114a, 114a) and the rotation prevention unit (127) formed in the shape of a rib or a lug at the stator (120) are coupled by press-fitting method, such that even if the rotor (described later) is rotated at a high speed or the housing (110) including the second housing (118) is heated at a high temperature, the stator (120) is prevented from rotating relative to the rotor.

Referring to FIG.42 again, the stator (120) is arranged at the first fixing unit (114a) of the lateral wall (114) of the second housing (118). The stator (120) includes a plurality of stator blocks (126), where the stator (120) may include 12 stator blocks (126), for example, and each stator block includes a stator core (122) and a coil (124).

The stator core (122) takes the shape of a letter "H" when viewed on a plan, and is formed by laminating a plurality of thin "H" shaped steel pieces. The coil (124) is wound on a concave portion of the stator core (122) in the predetermined coil turns. The stator core (122) at each stator block (126) and the coil (124) are made of an insulation material and insulated from each other.

Each of the plurality of block-shaped stator blocks (126) is assembled by way of press-fitting, including the coil (124) wound on the stator core (122), such that the stator (120) takes the shape of a ring when viewed on a plan. For example, the stator block (126) consists of 12.

The stator (120) shaped in a ring by the 12 assembled stator blocks (126) is press-fitted into the first fixing unit (114a) of the second housing (118) of the housing (110).

In the seventh exemplary embodiment, due to the fact that the stator (120) formed by assembling 12 stator blocks (126) is arranged in the accommodation space of the second housing (118), a much larger number of stator blocks, e.g., 12, can be arranged at an inner lateral surface (118a) of the second housing (118) over the conventional arrangement in the electric motor in the motor bicycle.

Referring to FIGS. 41 and 42, the external lateral surface opposite to the inner lateral surface of the second housing (118) in the stator core (122) of the stator block (126) at the stator (120) is formed with a rotation prevention groove (125) or a rotation prevention unit (127), and the rotation prevention groove (125) or the rotation prevention unit (127) is coupled to a rotation prevention unit (118a) or a rotation prevention groove (118b) formed at the first fixing unit (114a) of the second housing (118).

Referring to FIGS. 38 and 39 again, the rotor (130) includes a rotation shaft (132), a rotor core (134) and a magnet (136). In addition, the rotor (130) may further include a yoke (138) and a magnet sensor (139). The rotation shaft (132) is arranged in a hollow hole formed by the stator (120). A gap is formed between a periphery of the rotation shaft (132) and an inner circumferential surface of the stator (120), and the rotation shaft (132) is centrally arranged in the stator (120).

One distal end of the rotation shaft (132) is rotatably coupled to the first housing (112), and the other distal end opposite to the one distal end of the rotation shaft (132) is protruded to the outside through a through hole (116a) of the floor plate (116) of the second housing (118). The other distal end of the rotation shaft (132) protruded from the floor plate (116) of the second housing (118) may be coupled to a reduction gear (330) coupled to a transmission unit (300, described later).

The other distal end of the rotation shaft (132) is rotatably secured by a bearing (133) arranged on the first housing (112) as shown in FIG.2, and the other distal end opposite to the one distal end of the rotation shaft (132) is rotatably secured by a bearing (135) coupled to the inner lateral surface of a burring unit (116b) formed at the floor plate (116) of the second housing (118).

The rotor core (134) may include grooves formed on an upper surface of the rotor core (134) and a bottom surface opposite to the upper surface, or through holes (137) that pass the upper surface of the rotor core (134) and the bottom surface of the rotor core (134). The rotor core (134) may be formed with eight through holes (137), for example.

The magnet (136) takes the shape of a plate arranged inside the through hole (137) of the rotor core (134). The magnet takes the shape of a shape corresponding to that of the through hole (137). For example, in a case the through hole (137) takes the shape of a rectangle when viewed on a plan, the magnet (136) takes the shape of a rectangular parallelepiped. Alternatively, the rotor core (134) may take the shape of a curved plate, in a case the through hole (137) takes the shape of a curved shape.

A yoke (138) is arranged on an upper surface of the rotor core (134) to prevent the magnetic flux of the magnet (136) from leaking to other areas than an area of the stator (120). The yoke (138) may take the shape of a metal disc and be fastened to the upper surface of the rotor core (134) using a screw, for example.

As magnet sensor (139) is arranged on the yoke (138) and takes the shape of a doughnut. As shown in FIG.2, the magnet sensor (139) is formed on a position corresponding to that of a revolution count detection sensor (113a) of the circuit substrate (113).

Referring to FIGS. 38 and 39 again, the hub unit (200) encompasses the traction motor (100) and is rotatably arranged relative to the fixing shaft (50). The hub unit (200) includes a first hub unit (225) and a second hub unit (240), where the first hub unit (225) includes a lateral wall (210) and a floor plate (220).

A floor plate (220) of the first hub unit (225) is formed with a bushing unit (227) discrete from a periphery of the fixing shaft (50), and a bearing (228) may be interposed between the bushing unit (227) and the periphery of the fixing shaft (50) for the first hub unit (225) to rotate relative to the fixing shaft (50).

Referring to FIGS. 38 and 39, the transmission unit (300) functions to change a speed ratio between the rotation shaft (132) and the hub unit (200). For example, the transmission unit (300) changes the revolution count of the hub unit (200) relative to the rotation shaft (132) such that the hub unit (200) can rotate at a revolution lower than that of the rotation shaft (132).

The second tooth set (325) formed at the periphery of the second reduction gear (320) is meshed with the first tooth set of the first reduction gear (310). The third reduction gear (330) is coupled to a rotation shaft (132) protruded from the floor plate (116) of the second housing (118), and may include a sun gear formed at a periphery with a third tooth set. The third tooth set formed at the periphery of the third reduction gear (330) is meshed with the second tooth set of the second reduction gear (320).

In the present embodiment, the third tooth set of the third reduction gear (330) is formed with a first number of tooth sets, the second tooth set of the second reduction gear (320) is formed with a second number of tooth sets greater than the first number of tooth sets, and the first tooth set of the first reduction gear (310) is formed with a third number of tooth sets greater than the second number of tooth sets.

Therefore, the second reduction gear (320) is rotated at a revolution lower than that of the rotation shaft (132), as the third reduction gear (330) rotating at the same revolution as that of the rotation shaft (1321) is rotated, and the first reduction gear (310) is rotated at a revolution lower than that of the second reduction gear as the second reduction gear (320) is rotated. The hub unit (200) coupled to the first reduction gear (310) is rotated at a revolution much lower than that of the rotation shaft (132).

Referring to FIG.43, the stator includes a coupling piece (129a) and a plurality of stator blocks (129) including a lug unit (129b), where the plurality of stator blocks (129) is coupled in a ring shape to an inner lateral surface of the second housing (118).

An outer lateral surface of the coupling piece (129a) is formed with a rotation prevention groove (129c), and a lug-shaped rotation prevention unit (118c) is formed at an inner lateral surface of the second housing (118) opposite to the rotation prevention groove (129c) of the coupling piece (129a) to prevent the stator block (129) from rotating inside the second housing (118).

The traction motor module according to the seventh exemplary embodiment of the present invention has an advantageous effect in that a sill is formed for fixing the stator at an inner lateral surface of the housing of the traction motor, a lug or a groove is formed at the inner lateral surface of the housing, and a lug or a groove coupled to a lug or a groove of the housing is formed at the periphery of the stator to prevent the stator from rotating.

The previous description of the present invention is provided to enable any person skilled in the art to make or use the invention. Various modifications to the invention will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the spirit or scope of the invention. Thus, the invention is not intended to limit the examples described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

The traction motor module according to the present invention has an industrial applicability in that a motor bicycle is provided having a structure suitable for folding and storing the motor bicycle by greatly reducing size and weight through structural improvement of an electric motor.

The traction motor module according to the present invention has an industrial applicability in that it is free from destruction of a fixing shaft and/or a housing by a large load applied from outside through improvement of the fixing shaft and the housing of an electric motor.

The traction motor module according to the present invention has an industrial applicability in that a transmission pin is provided for mounting a transmission to an electric motor, and the traction motor module is free from increased size of the electric motor by using the transmission pin.

The traction motor module according to the present invention has an industrial applicability in that it is free from an excessive stress directly applied to a traction motor through rotation of a hub unit by fixing a stator of the traction motor to a fixing shaft and by arranging a rotor to an inner side of the stator to allow a rotation shaft to be rotatably supported by a motor bearing, by arranging the hub unit encompassing the traction motor to an outside of the traction motor, and by arranging a hub bearing to the hub unit.

The traction motor module according to the present invention has an industrial applicability in that a traction motor is provided that is configured to reduce the number of parts, size and weight of an electric motor by improving structure of a rotation shaft in the electric motor.

The traction motor module according to the present invention has an industrial applicability in that a traction motor is provided that is configured to reduce size of the traction motor module by arranging a rotor including a magnet to a rotation shaft, arranging a stator including a coil about the rotor, improving a structure of a housing to enable a secure fixture of the stator, and improving a rotational force inside the stator relative to the housing.

Claims

A traction motor module, the module comprising: a fixing shaft formed with a flange unit; a traction motor including a housing fixed at the fixing shaft, a stator fixed at an inner lateral wall of the housing, a rotation shaft arranged at a space formed by the stator and protruded from the housing, and a rotor including a magnet arranged between the stator and the rotation shaft; and a hub unit encompassing the traction motor in a cylindrical shape and rotatably coupled to the fixing shaft.
The module of claim 1, wherein the housing includes a first housing taking the shape of a plate and coupled to the flange unit, and a second housing accommodating the stator and the rotor and coupled to the first housing.
The module of claim 2, wherein the first housing is formed with a lug unit encompassing a lateral surface of the flange unit, where the lug unit is formed with a strength reinforcement unit by extending a part thereof toward the flange unit for reinforcing a coupling strength of the first housing.
The module of claim 3, wherein the lug unit protruded from the first housing in a circular shape.
The module of claim 4, wherein at least two strength reinforcement units are formed on the lug unit, each spaced apart at a same distance.
The module of claim 3, wherein an upper surface of the lug unit is arranged at a higher position than that of the flange unit.
The module of claim 3, wherein the strength reinforcement unit is brought into contact with the upper surface of the flange unit.
The module of claim 3, further comprising at least one fastening screw for fastening the flange unit and the first housing.
The module of claim 1, wherein the rotation shaft is inserted into a pin hole that goes through a floor plate connected to a lateral wall of the housing, where one lateral distal end is arranged on the same planar surface as that of an inner lateral surface of the floor plate, and the other lateral distal end opposite to the said one lateral distal end further includes a transmission gear pin protruded from an external lateral surface opposite to the inner lateral surface of the floor plate.
The module of claim 9, wherein the transmission gear pin includes a fixing unit having a first diameter and inserted into the pin hole, and a transmission gear coupling unit having a second diameter larger than the first diameter.
The module of claim 9, wherein a bushing unit is formed about the pin hole coupled to the transmission gear pin, where the bushing unit is protruded from the external lateral surface of the floor plate with a predetermined thickness.
The module of claim 9, wherein the transmission gear pin includes a fixing unit having a first diameter and inserted into the pin hole, and a transmission gear coupling unit having a second diameter smaller than the first diameter.
The module of claim 9, further comprising a ring-shaped first reduction gear formed along an inner lateral surface of the hub unit and formed at an inner surface with a first tooth set, a second reduction gear rotatably fixed at the transmission gear pin protruded from the external lateral surface of the floor plate and formed at a peripheral surface thereof with a second tooth set meshed with the first tooth set, and a third reduction gear coupled to the rotation shaft protruded from the housing and formed at a peripheral surface thereof with a third tooth set meshed with the second tooth set.
The module of claim 9, further comprising an insulation sheet interposed between the inner lateral surface of the floor plate and the rotor to prevent the rotor from contacting the floor plate.
The module of claim 1, further comprising a pair of motor bearings arranged on the housing to rotatably support the rotation shaft, and a pair of hub bearings arranged on the hub unit to rotatably support the hub unit relative to the traction motor.
The module of claim 15, wherein the housing includes a plate-shaped first housing, and a second housing coupled to the cylindrically shaped first housing, where the motor bearings include a first motor bearing coupled to the first housing and a second motor bearing coupled to the second housing.
The module of claim 16, wherein the second motor bearing is coupled to a burring unit protruded from the second housing toward an inner side.
The module of claim 15, wherein the hub unit includes a cylindrically shaped first hub unit encompassing part of the fixing shaft and the traction motor, and a plate-shaped second hub unit coupled to the first hub unit, and the hub bearings include the first hub bearing interposed between the first hub unit and the fixing shaft, and a second hub bearing coupled to the second hub unit.
The module of claim 1, further comprising a transmission unit interposed between a lateral wall of the housing protruded with the rotation shaft and a lateral wall of the hub unit opposite to the lateral wall of the housing to change a speed ratio between the rotation shaft and the hub unit.
The module of claim 1, wherein the rotor includes a rotor core coupled to the rotation shaft and mounted with the magnet, and further includes a transmission unit interposed between a lateral wall of the housing protruded with the rotation shaft and a lateral wall of the hub unit opposite to the lateral wall of the housing to change a speed ratio between the rotation shaft and the hub unit, where the rotation shaft includes a transmission gear unit formed at a distal lateral end of the rotation shaft protruded from the housing and formed with transmission tooth set to be coupled to the transmission unit.
The module of claim 20, wherein the rotation shaft includes a first bearing coupling unit arranged near the transmission gear unit, a rotor coupling unit arranged near the first bearing coupling unit, and a second bearing coupling unit arranged near the rotor coupling unit.
The module of claim 21, wherein the first and second bearing coupling units are coupled to first and second bearings coupled to the housing, and the rotor coupling unit is coupled to the rotor core fixed by the magnet.
The module of claim 22, wherein the rotor coupling unit is lengthwise formed with at least one rotor core rotation prevention unit along a peripheral surface of the rotation shaft for preventing the rotor core and the rotation shaft from slipping.
The module of claim 21, wherein the rotation shaft further includes a yoke coupling unit interposed between the rotor coupling unit and the second bearing coupling unit, where the yoke coupling unit is coupled to a yoke burring unit of a yoke.
The module of claim 24, wherein the yoke coupling unit is lengthwise formed with at least one yoke rotation preventing unit along a peripheral surface of the rotation shaft for preventing the yoke burring unit and the rotation shaft from slipping.
The module of claim 21, wherein each of the transmission gear unit, the first bearing coupling unit, the rotor coupling unit and the second bearing unit is formed with a sequentially reducing diameter.
The module of claim 21, wherein each of the transmission gear unit, the first bearing coupling unit, the rotor coupling unit and the second bearing unit is arranged on the same rotational center.
The module of claim 20, wherein the transmission unit includes a ring-shaped ring gear formed along an inner surface of the hub unit and formed thereinside with a tooth set, and a planetary gear rotatably fixed at a transmission gear pin protruded from an external lateral surface of the floor plate of the housing and formed at a peripheral surface thereof with a tooth set meshed with the tooth set of the ring gear and a tooth set of the transmission gear unit of the rotation shaft.
The module of claim 1, wherein the housing of the traction motor includes a first housing fixed to the fixing shaft and a second housing coupled to the first housing, the traction motor includes first and second bearings each arranged on the first and second housing, and coupled to the rotation shaft, the rotor includes a rotor core formed with a hollow hole and mounted with the magnet, and a rotation shaft support bar connecting the rotation shaft to the inner surface of the rotor core, and at least part of any one of the first and second bearings is arranged inside the hollow hole of the rotor core.
The module of claim 29, wherein the first bearing is fixed to the housing, the second bearing is fixed to the second housing, and part of the first and second bearings is arranged inside the hollow hole of the rotor core.
The module of claim 30, wherein at least two rotation shaft support bars are arranged, each spaced apart at a same distance.
The module of claim 29, further comprising a yoke body arranged at one lateral distal end of the rotor core opposite to the first housing, and a yoke extended from the yoke body and formed with a yoke burring unit coupled to the rotation shaft, and part of the yoke burring unit is arranged inside the hollow hole of the rotor core.
The module of claim 32, wherein at least part of the second bearing is arranged inside the hollow hole of the rotor core.
The module of claim 33, further comprising a magnet sensor arranged on the yoke body, and a circuit substrate arranged on the first housing opposite to the yoke body and opposite to the magnet sensor.
The module of claim 1, wherein a lateral distal end of the rotation shaft is protruded from the housing, and a lateral wall of the housing includes a first fixing unit press-fitted into the external lateral surface of the stator, and a second fixing unit supporting a lateral distal end of the stator.
The module of claim 35, wherein the lateral wall of the housing opposite to the first fixing unit has a first thickness, and the lateral wall of the housing opposite to the second fixing unit has a second thickness thicker than the first thickness.
The module of claim 35, wherein the first fixing unit is formed with a rotation prevention unit protruded from the first fixing unit, and the external lateral surface of the stator opposite to the rotation prevention unit is formed with a rotation prevention groove.
The module of claim 37, wherein at least two rotation prevention units are formed at the housing along the first fixing unit of the housing, and include any one shape of a rib or a lug.
The module of claim 35, wherein the first fixing unit is formed with a concave rotation prevention groove for preventing the stator from rotating, and a part opposite to the rotation prevention groove in the external lateral surface of the stator is formed with a rotation prevention unit protruded from the external lateral surface of the stator.
The module of claim 39, wherein at least two rotation prevention grooves formed at the housing are formed along the first fixing unit, and each of the rotation prevention grooves formed at the housing takes the shape of a groove.
The module of claim 35, wherein any one of a groove or a lug is formed at the lateral distal end of the stator, and the second stator opposite to the lateral distal end of the stator is formed with any one of a groove or a lug coupled to the groove or lug of the stator.
The module of claim 41, wherein the lateral distal end of the stator is formed with a groove.
The module of claim 41, wherein the lateral distal end of the stator is formed with a lug.
The module of claim 35, wherein the rotor includes a coupling piece having a same curvature as that of the housing, and a stator block including a lug unit protruded from an inner surface of the coupling piece toward a center of the housing, where a plurality of stator blocks are coupled, in a ring shape, along the inner surface of the housing, and an external lateral surface of the coupling piece is formed with a rotation prevention groove, and the inner surface of the housing opposite to the rotation prevention groove is formed with a lug-shaped rotation prevention unit.
The module of claim 1, further comprising a frame position determining washer inserted into the fixing shaft to determine a position of the frame fixed to the fixing shaft.
The module of claim 1, wherein a space is formed between a lateral wall of the housing protruded with the rotation shaft and the hub unit opposite to the lateral wall to accommodate a transmission unit for changing a speed ratio between the rotation shaft and the hub unit.
A traction motor module, the module comprising: a fixing shaft fixed at a frame; a traction motor including a housing fixed at the fixing shaft, cores fixed at an inner lateral wall of the housing, a rotation shaft arranged at a space formed by the cores and protruded from the housing, and a magnet arranged between the rotation shaft and the cores and coupled to the rotation shaft; a hub unit encompassing the traction motor in a cylindrical shape and rotatably coupled to the fixing shaft; and a transmission unit arranged between the lateral wall of the housing protruded with the rotation shaft and the lateral wall of the hub unit opposite to the lateral wall to change a speed ratio between the rotation shaft and the hub unit.
The module of claim 47, wherein the transmission unit includes a first reduction gear formed along an inner lateral surface of the hub unit and formed at an inner surface with a first tooth set, at least one second reduction gear rotatably fixed at the housing and formed at a peripheral surface thereof with a second tooth set meshed with the first tooth set, and a third reduction gear coupled to the rotation shaft protruded from the housing and formed at a peripheral surface thereof with a third tooth set meshed with the second tooth set.
The module of claim 47, wherein the first reduction gear includes a ring gear formed at an inner lateral surface thereof with the first tooth set, and the second reduction gear includes a planetary gear formed at an external lateral surface thereof with the second tooth set.
A traction motor module, the module comprising: a fixing shaft fixed to a frame; a fixing shaft fixed at a frame; a traction motor including a housing fixed at the fixing shaft, cores fixed at an inner lateral wall of the housing, a rotation shaft arranged at a space formed by the cores and protruded from the housing, and a magnet arranged between the rotation shaft and the cores and coupled to the rotation shaft; a hub unit encompassing the traction motor in a cylindrical shape and rotatably coupled to the fixing shaft; and a transmission unit arranged between the lateral wall of the housing protruded with the rotation shaft and the lateral wall of the hub unit opposite to the lateral wall to change a speed ratio between the rotation shaft and the hub unit, wherein the frame is asymmetrically formed at one side of a wheel connected to the hub unit among the one side of the wheel and the other side opposite to the one side.
The module of claim 50, wherein the frame includes a first frame unit arranged on a straight line with the wheel, and a second frame unit bent from the first frame and extended to the one side of the wheel, wherein the fixing shaft is coupled to the second frame unit.