Bicycle hub motor with housing positioning structure

Abstract

A bicycle hub motor with a housing positioning structure, comprising: a shaft assembly comprising a shaft and a stator seat, wherein an axis of rotation is defined by the centerline of the shaft and the stator seat is connected to the outer circumferential surface of the shaft; a hub comprising a main body, an annular connecting element, and a side cover, wherein the main body has a receiving chamber with an opening, multiple spoke seats are formed on the outer circumferential surface of the main body, a first through-hole is provided in the center of the main body, the stator seat is accommodated in the receiving chamber, the annular connecting element is combined with the inner circumferential surface of the main body and adjoins the opening, the circumference of the side cover is combined with the main body to cover the opening and to abut the annular connecting element, and a hole is provided in the center of the side cover.a first protruding ring is connected to the circumference of the inside of the side cover corresponding to the hole, a contact surface is formed on the inside of the side cover between the hole and the first protruding ring, the inner circumferential surface of the first protruding ring forms a boundary surface, and the contact surface and the boundary surface are not parallel to each other; a motor arranged in the receiving space and comprising a stator and a rotor, wherein the stator is mounted around the outer circumferential surface of the stator seat and the rotor is arranged around the circumference of the stator and is rotatable relative to it; a rotor seat combined with the rotor and rotatably mounted on the shaft about the axis of rotation; and a ratchet seat comprising a hub connection section and a pinion connection section, wherein the hub connection section has a disc section, the disc section being combined with the contact surface.the outer circumferential surface of the disc section is in contact with the boundary surface, the pinion connection section is rotatably mounted around the shaft, a unidirectional drive structure is arranged between the pinion connection section and the hub connection section, and several detent grooves are provided on the radial outer circumferential surface of the pinion connection section.

Description

Field of invention The present invention relates to a bicycle hub motor and in particular to a bicycle hub motor with a housing positioning structure. State of the art It is known that a hub motor sets its housing in rotation by means of an internal drive mechanism. When such a hub motor is used in a bicycle, it is usually attached to the axle assembly of the front or rear wheel, with the hub motor housing being rigidly connected to the wheel. When the hub motor is activated, the internal drive mechanism causes the housing to rotate, thereby setting the wheel connected to the hub motor housing in motion to produce a pedal-assist effect. However, conventional hub motors typically lack a well-designed concentric positioning structure between the drive mechanism and the housing. Furthermore, the housing itself lacks a positioning structure to improve concentricity, leading to assembly problems such as shaft misalignment or structural eccentricity. While these issues have been mitigated in some products through improved manufacturing tolerances, the absence of an effective geometric positioning structure still results in problems like difficult assembly or positional deviations. These issues not only compromise assembly efficiency but can also shorten the hub motor's lifespan. Object of the invention One object of the present invention is to provide a bicycle hub motor with a housing positioning structure which can improve the concentricity between the drive mechanism and the housing and thereby reduce problems such as shaft misalignment and eccentricity. To solve the aforementioned problems, the present invention provides a bicycle hub motor with a housing positioning structure comprising a shaft assembly, a hub, a motor, a rotor seat, and a ratchet seat, wherein the shaft assembly comprises a shaft and a stator seat, an axis of rotation L is defined by the centerline of the shaft, and the stator seat is connected to the outer circumferential surface of the shaft; wherein the hub comprises a main body, an annular connecting element, and a side cover, the main body has a receiving chamber with an opening, several spoke seats are formed on the outer circumferential surface of the main body, a first through-hole is provided in the center of the main body, the stator seat is accommodated in the receiving chamber, the annular connecting element is combined with the inner circumferential surface of the main body and adjoins the opening,to cover the opening and to abut the annular connecting element, the circumference of the side cover is combined with the main body, a hole is provided in the center of the side cover, a first projecting ring is connected to the circumference of the inside of the side cover corresponding to the hole, a contact surface is formed on the inside of the side cover between the hole and the first projecting ring, the inner circumferential surface of the first projecting ring forms a boundary surface, and the contact surface and the boundary surface are not parallel to each other; wherein the motor is arranged in the receiving space and comprises a stator and a rotor,the stator is mounted around the outer circumferential surface of the stator seat and the rotor is arranged around the circumference of the stator and rotatable relative to it; wherein the rotor seat is combined with the rotor and rotatably mounted on the shaft about the axis of rotation; wherein the ratchet seat comprises a hub connection section and a pinion connection section, the hub connection section has a disk section, the disk section is combined with the contact surface, the outer circumferential surface of the disk section is in contact with the boundary surface, the pinion connection section is rotatably mounted about the shaft, a unidirectional drive structure is arranged between the pinion connection section and the hub connection section, and several detent grooves are provided on the radial outer circumferential surface of the pinion connection section. The present invention achieves the effect that the side cover, through its contact surface and boundary surface formed by the first projecting ring, enables precise positioning and alignment with the disc section of the ratchet seat located in the center of the side cover. This ensures that the ratchet seat is also rotated concentrically to the axis of rotation. During assembly, this allows for precise alignment of the shaft assembly, thereby preventing misalignment of the shaft assembly and the resulting assembly problems. Brief description of the drawings Fig. 1 shows a perspective view according to a preferred embodiment of the bicycle hub motor according to the invention with housing positioning structure; Fig. 2 shows a partial exploded view according to the preferred embodiment of the bicycle hub motor according to the invention with housing positioning structure; Fig. 3 shows a partial exploded view according to Fig. 2 from a different perspective; Fig. 4 shows an exploded view of the shaft arrangement; Fig. 5 shows a front view according to the preferred embodiment of the bicycle hub motor according to the invention with housing positioning structure; Fig. 6 shows a sectional view along section line 6-6 according to Fig. 5; Fig. 6A shows a sectional view similar to Fig. 6, showing the connection method of the reduction mechanism; Fig. 7 shows a sectional view along section line 7-7 according to Fig. 5. Detailed description of the exemplary embodiment To better explain the present invention, a preferred embodiment is described in detail below with reference to the drawings. Reference is made to Figures 1 to 3 and 6, which show the bicycle hub motor with housing positioning structure 100 according to a preferred embodiment of the present invention. It comprises a shaft assembly 10, a hub 20, a motor 30, a rotor seat 40, a reduction mechanism 50, and a ratchet seat 60. The bicycle hub motor 100 is described below, explaining the front / rear and top / bottom directions of the individual components of the bicycle hub motor 100 with respect to their state during use. As shown in Figures 4, 5 to 6, the shaft assembly 10 comprises a shaft 12 and a stator seat 14, wherein the shaft 12 has a first shaft section 121 and a second shaft section 122, an axis of rotation L being defined by the centerline of the first shaft section 121 and the second shaft section 122 and serving as the center of rotation of the bicycle hub motor 100. The first shaft section 121 has a hollow tube 1211, one end of which forms a mounting hole 1212. The mounting hole 1212 is non-circular, its non-circular inner circumferential surface being substantially round and having two opposing parallel surfaces. The outer circumferential surface of the end of the second shaft section 122 facing the first shaft section 121 is a non-circular outer circumferential surface 1221, which is adapted to the shape of the mounting hole 1212.The end of the second shaft section 122, which has a non-circular outer circumferential surface 1221, is engaged in the mounting hole 1212, so that the second shaft section 122 is combined with the first shaft section 121 and cannot rotate relative to it. The stator seat 14 is a circular disk whose inner circumferential surface is connected to the outer circumferential surface of the hollow tube 1211. As shown in Figures 2, 5, and 6, the hub 20 comprises a main body 22, an annular connecting element 24, and a side cover 25. The main body 22 is designed as a transversely arranged housing structure, with an opening 221 on the right side of the main body 22. The main body 22 has several spoke seats 222, a first through-hole 223, and a receiving space S, wherein the spoke seats 222 are arranged on the outer circumferential surface of the main body 22, and the two ends of the bicycle spokes are each connected to the spoke seats 222 and the rim of the bicycle. When the main body 22 rotates, the bicycle spokes drive the bicycle rim to rotate. The first through-hole 223 is located in the center on the left side of the main body 22 and has a main body bearing seat 2231 into which a first bearing 26 is inserted.The hollow tube 1211 of the first shaft section 121 is rotatably mounted through the first bearing 26, so that the main body 22 is rotatably mounted about the first shaft section 121 via the first bearing 26. Accordingly, when the first shaft section 121 is fixed, the main body 22 can rotate about the axis of rotation L relative to the first shaft section 121. Inside the main body 22 is the receiving chamber S, with the opening 221 located on the right side of the receiving chamber S. The receiving chamber S serves to accommodate the stator seat 14, the motor 30, the rotor seat 40, and the reduction mechanism 50. As shown in Figures 2 and 3, as well as 5 and 6, the annular connecting element 24 is a ring body and is screwed to the inner circumferential surface of the main body 22. The annular connecting element 24 borders the opening 221 and has an annular positioning groove 241 on its outer surface facing the opening 221. The side cover 25 is a circular cover body whose circumference is screwed to the main body 22, so that the side cover 25 covers the opening 221 and rests against the annular connecting element 24. The side cover 25 has a hole 251, a first projecting ring 252, and a second projecting ring 253, with the hole 251 being located in the center of the side cover 25. The first projecting ring 252 is arranged on the circumference of the inner surface of the side cover 25 corresponding to the hole 251.A contact surface 254 is formed on the inside of the side cover 25 between the first projecting ring 252 and the hole 251. The inner circumferential surface of the first projecting ring 252 forms a boundary surface 255, wherein the contact surface 254 and the boundary surface 255 are not parallel to each other. In the present preferred embodiment, the boundary surface 255 is perpendicular to the contact surface 254. The second projecting ring 253 is arranged on the circumference of the inside of the side cover 25 and snapped into the positioning groove 241, thereby improving the concentricity between the side cover 25 and the main body 22 during assembly. As shown in Figures 5 and 6, the motor 30 comprises a stator 32 and a rotor 34, wherein the stator 32 is attached to the outer circumferential surface of the stator seat 14, a third projection ring 341 is combined with the outer surface of the rotor 34, and the rotor 34 is spaced from and surrounds the stator 32. The rotor seat 40 has a rotor seat positioning groove 41 and a rotor bearing seat 42, wherein the third projection ring 341 is engaged in the rotor seat positioning groove 41, so that when the rotor 34 rotates, the rotor seat 40 rotates with it. The rotor bearing seat 42 is located in the center of the rotor seat 40, with two third bearings 43 being inserted into the rotor bearing seat 42 and a part of the second shaft section 122 passing through the two third bearings 43, so that the rotor 34 and the rotor seat 40 are rotatably mounted about the second shaft section 122 via the two third bearings 43. As shown in Figures 5 and 6, a power cable 70 is externally connected to the bicycle hub motor 100. The power cable 70 is electrically connected to the stator 32, causing current to flow into the stator 32 and generating an electromagnetic field. This generates a driving force that sets the rotor 34 in motion, thus rotating the rotor seat 40 relative to the stator 32 about the axis of rotation L. The rotational speed of the rotor 34 relative to the stator 32 can be controlled by changing the input voltage or frequency. As shown in Fig. 6A, the reduction mechanism 50 comprises an input end 51, an output end 52, a planet carrier 53, several first planet gears 54, and several second planet gears 55. The input end 51 is an annular sun gear combined concentrically with the central section of the rotor seat 40, and the second shaft section 122 passes through the center of the input end 51, so that the input end 51 is rotatably arranged about the second shaft section 122. The output end 52 is a circular gear ring combined with the annular connecting element 24. The planet carrier 53 is an annular body provided with several annularly arranged shaft holes 531 and surrounds the second shaft section 122. It is rotatable about the axis of rotation L relative to the second shaft section 122. A pin 56 is rotatably passed through each shaft hole 531.The first planet gears 54 are arranged in a ring around the input end 51 and each engages with it, the center point of each first planet gear 54 being rotatably combined with one end of the corresponding pin 56. The second planet gears 55 are arranged in a ring and each engages with the output end 52, the center point of each second planet gear 55 being rotatably combined with the other end of this pin 56. In operation, the rotor seat 40 drives the input end 51 to rotate, the input end 51 driving the first planet gears 54 to rotate, which in turn drive the planet carrier 53 and the second planet gears 55 to rotate, the second planet gears 55 engaging with the output end 52, thereby finally rotating the annular connecting element 24 at a lower speed than the input end 51 to achieve a reduction effect.As shown in Figures 2, 3, and 7, the ratchet seat 60 comprises a hub connection section 62 and a pinion connection section 64, the hub connection section 62 having a cylindrical body 621 and a disc section 622. The cylindrical body 621 is a tubular cylinder whose inner diameter is slightly larger than that of the second shaft section 122. The cylindrical body 621 is rotatably mounted about the second shaft section 122. Three pawl recesses 623 are provided on the outer circumferential surface of the cylindrical body 621, each containing a pawl 624. The disc section 622 is connected to the inner end of the cylindrical body 621 at its inner circumferential surface and has several first holes for fastening elements 625 as well as a second through-hole 626. During assembly, the cylinder body 621 is passed through the hole 251, causing the disc section 622 to rest against the contact surface 254.The mounting surface 254 has several second holes for fasteners 256 at the positions corresponding to the first holes for fasteners 625, through each of which a fastener 27 passes. The fasteners 27 pass through the corresponding first holes for fasteners 625, thereby combining the disc section 622 with the mounting surface 254, with the outer circumferential surface of the disc section 622 being in contact with the boundary surface 255, thus improving the concentricity between the hub connection section 62 and the side cover 25. As shown in Figs. 2, 3 and 6, the second through-hole 626 is located in the center of the disc section 622 and has a disc section bearing seat 6261 into which a second bearing 66 is inserted. The other end of the second shaft section 122 is rotatably passed through the second bearing 66 and the cylinder body 621. The hub connection section 62 is rotatably mounted about the second shaft section 122 via the second bearing 66 and is rotatable about the axis of rotation L relative to the second shaft section 122. As shown in Figs. 2, 3 and 7, the pinion connection section 64 is a cylindrical body rotatably mounted about the hub connection section 62. The pinion connection section 64 has several locking teeth 641 and several detent grooves 642, the locking teeth 641 being arranged annularly on the inner circumferential surface of the pinion connection section 64 and each pawl 624 being unidirectionally engaged with a locking tooth 641. A unidirectional drive structure X is thus formed between the hub connection section 62 and the pinion connection section 64, i.e. the pinion connection section 64 can only drive the hub connection section 62 to rotate in the forward direction, while in the case of a reverse rotation of the pinion connection section 64 the pinion connection section 64 cannot drive the hub connection section 62 to rotate in the reverse direction.The locking grooves 642 are arranged on the radial outer circumferential surface of the sprocket connection section 64 and serve for combination with a freewheel sprocket (not shown). The bicycle chain is placed around the freewheel sprocket. When the user pushes the bicycle pedals forward, the chain drives the freewheel sprocket, which in turn rotates the hub 20 of the bicycle hub motor 100 via the unidirectional drive structure X. In summary, the effects of the present invention are that the side cover 25 is engaged in the positioning groove 241 of the annular connecting element 24 by means of the second projection ring 253 and screwed to the main body 22, thereby improving the concentricity between the main body 22 and the side cover 25. This ensures that both the first through-hole 223 of the main body 22 and the hole 251 of the side cover 25 are aligned concentrically with the axis of rotation L. Furthermore, the side cover 25, through its contact surface 254 and limiting surface 255 formed by enclosing the first projection ring 252, enables precise positioning and alignment with the disc section 622 of the ratchet seat 60 located in the center of the side cover 25. This ensures that the ratchet seat 60 is also rotated concentrically with the axis of rotation L.During assembly, this enables precise alignment of the shaft arrangement 10, thereby avoiding misalignment of the shaft arrangement 10 and resulting assembly problems. The foregoing description represents only one preferred embodiment of the invention. All equivalent changes and modifications that can be made by a person skilled in the art according to the description and drawings of the invention are within the scope of protection of the present invention. Reference symbol list 100 Bicycle hub motor 10 Shaft assembly 12 Shaft 121 First shaft section 1211 Hollow tube 1212 Mounting hole 122 Second shaft section 1221 Non-circular outer circumferential surface 14 Stator seat 20 Hub 22 Main body 221 Opening 222 Spoke seat 223 First through hole 2231 Main body bearing seat 24 Annular connecting element 241 Positioning groove 25 Side cover 251 Hole 252 First protruding ring 253 Second protruding ring 254 Contact surface 255 Limiting surface 256 Second hole for fasteners 26 First bearing 27 Fastener 30 Motor 32 Stator 34 Rotor 341 Third protruding ring 40 Rotor seat 41 Rotor seat positioning groove 42 Rotor bearing seat 43 Third bearing 50 Reduction mechanism 51 Input end 52 Output end 53 Planet carrier 531 Shaft hole 54 First planet gear 55 Second planet gear 56 Pin 60 Ratchet seat 62 Hub connection section 621 Cylinder body 622 Disc section 623 Pawl recess 624 Pawl 625 First hole forFastening elements 626 second through hole 6261 disc section bearing seat 64 pinion connection section 641 locking tooth 642 detent groove 66 second bearing 70 power cable L axis of rotation S receiving space X unidirectional drive structure

Claims

A bicycle hub motor with a housing positioning structure, comprising: a shaft assembly comprising a shaft and a stator seat, wherein an axis of rotation is defined by the centerline of the shaft and the stator seat is connected to the outer circumferential surface of the shaft; a hub comprising a main body, an annular connecting element, and a side cover, wherein the main body has a receiving chamber with an opening, multiple spoke seats are formed on the outer circumferential surface of the main body, a first through-hole is provided in the center of the main body, the stator seat is accommodated in the receiving chamber, the annular connecting element is combined with the inner circumferential surface of the main body and adjoins the opening, the circumference of the side cover is combined with the main body to cover the opening and to abut the annular connecting element, and a hole is provided in the center of the side cover.a first protruding ring is connected to the circumference of the inside of the side cover corresponding to the hole, a contact surface is formed on the inside of the side cover between the hole and the first protruding ring, the inner circumferential surface of the first protruding ring forms a boundary surface, and the contact surface and the boundary surface are not parallel to each other; a motor arranged in the receiving space and comprising a stator and a rotor, wherein the stator is mounted around the outer circumferential surface of the stator seat and the rotor is arranged around the circumference of the stator and is rotatable relative to it; a rotor seat combined with the rotor and rotatably mounted on the shaft about the axis of rotation; and a ratchet seat comprising a hub connection section and a pinion connection section, wherein the hub connection section has a disc section, the disc section being combined with the contact surface.the outer circumferential surface of the disc section is in contact with the boundary surface, the pinion connection section is rotatably mounted around the shaft, a unidirectional drive structure is arranged between the pinion connection section and the hub connection section, and several detent grooves are provided on the radial outer circumferential surface of the pinion connection section. Bicycle hub motor with housing positioning structure according to claim 1, wherein the disc section has several first holes for fastening elements, wherein the contact surface at the positions corresponding to the first holes for fastening elements has several second holes for fastening elements, through each of which a fastening element is passed, and the fastening elements are passed through the corresponding first holes for fastening elements. Bicycle hub motor with housing positioning structure according to claim 1, wherein the first through-hole of the main body has a main body bearing seat, a first bearing is inserted into the main body bearing seat, a second through-hole is provided in the center of the disc section, the second through-hole has a disc section bearing seat, a second bearing is inserted into the disc section bearing seat, one end of the shaft is passed through the first bearing and the other end of the shaft is passed through the second bearing. Bicycle hub motor with housing positioning structure according to claim 3, wherein the shaft has a first shaft section and a second shaft section, the first shaft section has a hollow tube, the hollow tube is rotatably passed through the first bearing and forms a mounting hole at the end facing the opening, the mounting hole is not circular, one end of the second shaft section is engaged in the mounting hole and the other end of the second shaft section is rotatably passed through the second bearing. Bicycle hub motor with housing positioning structure according to claim 4, wherein the inner circumferential surface of the stator seat is connected to the outer circumferential surface of the hollow tube. Bicycle hub motor with housing positioning structure according to claim 1, wherein the circumference of the inside of the side cover is connected to a second projection ring, the annular connecting element has an annular positioning groove on its outer side facing the opening, and the second projection ring is engaged in the positioning groove. Bicycle hub motor with housing positioning structure according to claim 1, wherein the pinion connection section is provided with several locking teeth, the hub connection section is provided with several pawl recesses, each pawl recess is provided with a pawl and each pawl is unidirectionally engaged with a locking tooth. Bicycle hub motor with housing positioning structure according to claim 1, further comprising a reduction mechanism arranged in the receiving space and having an input end and an output end, wherein the input end is a sun gear and is centrally combined with the rotor seat and rotatably arranged around the shaft, wherein the output end is a toothed ring and is combined with the annular connecting element. Bicycle hub motor with housing positioning structure according to claim 8, wherein the reduction mechanism further comprises a planet carrier, several first planet gears and several second planet gears, wherein the planet carrier surrounds the shaft, the first planet gears are each rotatably combined with one side of the planet carrier and are arranged annularly around the circumference of the input end and are engaged with it, and the second planet gears are each rotatably combined with the other side of the planet carrier and are engaged annularly with the output end. Bicycle hub motor with housing positioning structure according to claim 9, wherein the planetary gear carrier has several ring-shaped shaft holes through which a pin is rotatably passed, wherein the center point of a respective first planetary gear is rotatably combined with one end of the corresponding pin and the center point of a respective second planetary gear is rotatably combined with the other end of this pin.

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