Rear wheel hub structure and bicycle

Abstract

The utility model relates to the technical field of bicycles, and particularly discloses a rear wheel hub structure and a bicycle, the rear wheel hub structure comprises a hub, a key shaft, a flywheel, a transmission rod and an external assembly; the key shaft coaxially penetrates through the axis of the hub, the key shaft and the hub are fixed in the circumferential direction, one end of the key shaft is connected with the transmission rod, and the other end of the key shaft is connected with the external assembly; a ratchet wheel part is arranged on the outer wall of the transmission rod, one end of the transmission rod is coaxially connected with the key shaft, and the transmission rod and the key shaft are circumferentially fixed; a sprocket part is arranged on the outer wall of the flywheel, a cavity is formed in the flywheel, and an inner gear ring capable of being matched with the ratchet wheel part is arranged on the inner wall of the cavity.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of bicycle, especially the parts of bicycle. BACKGROUND

[0002] The rear wheel of the bicycle is mainly composed of a rim, spokes and a hub, and a freewheel is installed on the hub for connecting a chain, so that the user can drive the rear wheel to rotate by pedaling the pedal, wherein, in order to facilitate the installation of the freewheel, a tower is provided on the hub for installing multiple freewheels, and the external speed change is realized by the rear derailleur, however, the traditional rear wheel transmission and speed change structure is complex, large in size, and the transmission assembly is exposed, and it is impossible to realize the full-sealed transmission and simple and lightweight structure. SUMMARY

[0003] Therefore, the utility model provides a rear wheel hub structure and bicycle for solving the technical problem that the rear wheel hub structure in the prior art cannot realize the full-sealed transmission and simple and lightweight structure.

[0004] To achieve one or part or all of the above purposes or other purposes, the utility model provides a rear wheel hub structure, which comprises a hub, a key shaft, a freewheel, a transmission rod and an external component.

[0005] The key shaft penetrates the shaft center of the hub coaxially, and the key shaft is fixed circumferentially with the hub, one end of the key shaft is connected with the transmission rod, and the other end of the key shaft is connected with the external component.

[0006] The outer wall of the transmission rod is provided with a ratchet part, one end of the transmission rod is connected coaxially with the key shaft, and the transmission rod is fixed circumferentially with the key shaft.

[0007] The outer wall of the freewheel is provided with a chain tooth part, the inside of the freewheel is provided with a cavity, and the inner wall of the cavity is provided with an inner tooth ring matched with the ratchet part.

[0008] Preferably, the ratchet part comprises a ratchet seat and a plurality of clamping claws, a plurality of mounting grooves are arranged on the ratchet seat corresponding to the plurality of clamping claws, one end of the clamping claw is rotatably connected with the mounting groove, the other end of the clamping claw can be extended out of the mounting groove and engaged with the inner tooth ring, an elastic element connected with the back of the clamping claw is arranged in the mounting groove, and the compression direction of the elastic element is the same as the rotation direction of the transmission rod.

[0009] Preferably, one end of the mounting groove is provided with a concave groove, and one end of the clamping claw is provided with a connecting cylinder matched with the concave groove.

[0010] Preferably, the mounting groove is provided with a right-angle groove at the end away from the concave groove, the elastic element is fixed in the right-angle groove, and one end of the elastic element is connected with the clamping claw.

[0011] Preferably, the shaft center of the hub is provided with a first connecting hole penetrating through both ends, and the key shaft penetrates and inserts the first connecting hole.

[0012] One end of the transmission rod is provided with a second connecting hole connected with the key shaft; the cross section of the first connecting hole and the cross section of the second connecting hole are the same as the cross section of the key shaft.

[0013] Preferably, a fixing screw is further included, the key shaft is hollowly arranged, a threaded hole coaxial with the second connecting hole is arranged in the transmission rod, one end of the fixing screw penetrates the key shaft and the second connecting hole in sequence and is threadedly connected with the threaded hole, so as to limit the axial movement between the transmission rod and the key shaft.

[0014] Preferably, the transmission rod is provided with an inner end connecting portion and an outer end connecting portion on both sides of the ratchet portion respectively; the rear wheel hub structure further includes a transmission assembly, the transmission assembly includes a first inner bearing, a second inner bearing, a first outer bearing and a limiting ring;

[0015] The limiting ring is arranged in the cavity of the flywheel, and the limiting ring is threadedly connected with the outer end connecting portion; the limiting ring can abut against the side wall of the inner tooth ring to limit the axial movement of the transmission rod and the flywheel, and the limiting ring is connected with the inner wall of the cavity of the flywheel through the first inner bearing;

[0016] The second inner bearing is sleeved on the inner end connecting portion of the transmission rod, and the inner end connecting portion is connected with the inner wall of the cavity of the flywheel through the second inner bearing; the second inner bearing and the first inner bearing are distributed on both sides of the ratchet portion;

[0017] The first outer bearing is sleeved on the outer wall of the flywheel.

[0018] Preferably, the external connecting assembly includes an external connecting piece and a second outer bearing;

[0019] The internal portion of the external connecting piece is provided with a limiting hole and a third connecting hole coaxially communicated; the inner diameter of the limiting hole is greater than the inner diameter of the third connecting hole; the cross section of the third connecting hole is the same as the cross section of the key shaft; and the end portion of the key shaft is provided with an end cap, and the end cap is arranged in the limiting hole;

[0020] The second outer bearing is sleeved on the outer wall of the external connecting piece.

[0021] Preferably, a brake pad is further included, both ends of the hub are provided with fixing hole positions for mounting the brake pad, and the brake pad is mounted on any one end of the hub through the fixing hole position.

[0022] A bicycle includes the rear wheel hub structure, a frame, two inner side sealing rings and an outer side sealing ring.

[0023] The frame is provided with two connecting cavities; one connecting cavity of the frame is connected with the flywheel through the first outer bearing; and the other connecting cavity of the frame is connected with the external connecting piece through the second outer bearing.

[0024] Two inner sealing rings are respectively arranged at the inner ends of the two connecting cavities, and the outer wall of the inner sealing ring is provided with a sealing ring, and the two inner sealing rings are arranged between the frame and the hub;

[0025] The outer sealing ring is fixedly connected with the outer connecting piece, and a sealing ring is arranged between the inner wall of the outer sealing ring and the outer wall of the outer connecting piece.

[0026] The embodiment of the present application has the following beneficial effects:

[0027] After the above rear wheel hub structure is adopted, the rear wheel hub structure establishes torque transmission through the key shaft and the transmission rod, under the condition of ensuring stable torque transmission, the internal space of the hub is reasonably utilized, so that the structure of the rear wheel hub structure is more compact, the whole is more lightweight, and the strength of the hub itself can be further ensured by the key shaft penetrating the hub; The ratchet part provided on the outer wall of the transmission rod and the inner tooth ring in the freewheel realize one-way meshing, so as to ensure that the rotation of the freewheel can drive the hub to rotate, and realize the one-way free rotation effect of the freewheel when the hub rotates; After the rear wheel hub structure provided in the embodiment is installed on the frame of the bicycle, the rear wheel transmission of the bicycle realizes full sealing through the structure layout of the plurality of sealing rings and the rear wheel hub structure itself, and the overall structure is simple and lightweight, the hub is connected with the transmission structure at both ends through the key shaft, and has the advantage of convenient disassembly of the wheel set. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without creating any creative labor.

[0029] Among them:

[0030] Figure 1 It is a schematic diagram of the overall structure of the bicycle applying the rear wheel hub structure in the present application;

[0031] Figure 2 It is a partial explosion Figure 1 ;

[0032] Figure 3 It is a partial explosion Figure 2 ;

[0033] Figure 4 It is Figure 1 A-A sectional view in the figure;

[0034] Figure 5is an enlarged view of part C in Figure 4 is a sectional view along B-B in

[0035] Figure 6 is an enlarged view of part C in Figure 4 is a sectional view along B-B in

[0036] Figure 7 is an enlarged view of part C in Figure 6 is a sectional view along B-B in

[0037] Figure 8 is a structural schematic view of a flower drum in the utility model;

[0038] Figure 9 is a structural schematic view of a flywheel in the utility model;

[0039] Figure 10 is a structural schematic view of a transmission rod in the utility model Figure 1 ;

[0040] Figure 11 is a structural schematic view of a transmission rod in the utility model Figure 2 ;

[0041] Figure 12 is a structural schematic view of an external connecting piece in the utility model.

[0042] Reference signs:

[0043] 1 flower drum, 10 first connecting hole, 2 key shaft, 20 end cap, 3 flywheel, 30 inner tooth ring, 301 tooth, 31 chain tooth part, 4 transmission rod, 40 ratchet part, 400 ratchet seat, 401 installation slot, 401a concave groove, 401b right angle groove, 402 clamping jaw, 402a connecting cylinder, 403 elastic piece, 403a supporting section, 403b deformation section, 41 second connecting hole, 42 threaded hole, 43 inner end connecting part, 44 outer end connecting part, 5 fixed screw rod, 6 external connecting assembly, 60 external connecting piece, 600 limiting hole, 601 third connecting hole, 61 second outer bearing, 7 transmission assembly, 70 limiting ring, 71 first inner bearing, 72 second inner bearing, 73 first outer bearing, 8 frame, 80 connecting cavity, 81 inner side sealing ring, 82 outer side sealing ring, 83 sealing ring, 84 wheel rim, 85 spoke, 9 brake pad. DETAILED DESCRIPTION

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the specification herein is for describing particular embodiments only and is not intended to be limiting of the application; the use herein of terms such as "comprise", "comprises", "comprising", "containing", "contains", "contain" or any other variation thereof is intended to cover a non-exclusive inclusion, such that these terms are used in their broadest context to include a variety of embodiments. The terms "first", "second", and the like, herein do not denote any ordinal, quantity or order, but are used to distinguish one element from another.

[0045] Reference herein to "embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase that in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another. It is expressly understood that the embodiments described herein are merely examples from a

[0046] In order to make the person skilled in the art better understand the technical scheme of the application, the technical scheme in the embodiments of the application will be clearly and completely described below with reference to the drawings.

[0047] As shown in the accompanying Figures 1-12 embodiments provided by the application.

[0048] The embodiment of the application provides a rear wheel hub structure, which comprises a hub 1, a key shaft 2, a flywheel 3, a transmission rod 4 and an external component 6; the key shaft 2 is coaxially through the shaft center of the hub 1, and the key shaft 2 is fixed in the circumferential direction of the hub 1; one end of the key shaft 2 is connected with the transmission rod 4, and the other end of the key shaft 2 is connected with the external component 6; the outer wall of the transmission rod 4 is provided with a ratchet part 40; one end of the transmission rod 4 is coaxially connected with the key shaft 2, and the transmission rod 4 is fixed in the circumferential direction of the key shaft 2; the outer wall of the flywheel 3 is provided with a chain tooth part 31; the inside of the flywheel 3 is provided with a cavity, and the inner wall of the cavity is provided with an inner tooth ring 30 which can cooperate with the ratchet part 40.

[0049] Specifically, the hub 1 is connected with the rim 84 through a plurality of spokes 85, and the inner tire and the outer tire are installed outside the rim 84, thereby forming the rear wheel of the bicycle; in order to realize the driving rotation of the hub 1, the first connecting hole 10 is arranged on the shaft center of the hub 1, the key shaft 2 passes through the first connecting hole 10, and the rotation of the key shaft 2 drives the hub 1 to rotate together, wherein the cross section of the first connecting hole 10 is the same as the cross section of the key shaft 2, the cross section of the key shaft 2 can adopt quadrilateral, pentagon, hexagon or semicircle and the like, and the hexagonal shape is preferred in the embodiment, the force of the key shaft 2 in this shape is more balanced, and the torque transmission is more stable, and then the second connecting hole 41 is arranged on the end of the transmission rod 4, the cross section of the second connecting hole 41 adopts the same hexagonal shape as the cross section of the key shaft 2, the end of the key shaft 2 is inserted into the second connecting hole 41, and when the transmission rod 4 rotates, the key shaft 2 can be driven to rotate together, in order to limit the axial movement of the transmission rod 4 and the key shaft 2, the embodiment further comprises a fixed screw 5, the key shaft 2 is hollow, the transmission rod 4 is provided with a threaded hole 42 coaxial with the second connecting hole 41, one end of the fixed screw 5 passes through the key shaft 2, the second connecting hole 41 and is threadedly connected with the threaded hole 42, so as to limit the axial movement between the transmission rod 4 and the key shaft 2; the embodiment is provided with a ratchet part 40 on the transmission rod 4, and a ring of internal teeth 30 is arranged at the middle position of the inner wall of the cavity of the freewheel 3, a plurality of teeth 301 are arranged in the internal teeth 30 and matched with the ratchet part 40, the forward rotation of the freewheel 3 is realized to engage with the ratchet part 40, thereby driving the rotation of the transmission rod 4, the hub 1 is driven to rotate together through the key shaft 2, and the driving of the rear wheel of the bicycle is realized, and when the rear wheel of the bicycle is idling, the freewheel 3 is stationary relative to the transmission rod 4 due to the one-way driving effect of the ratchet part 40; it should be further pointed out that a plurality of bearings can be arranged between the transmission rod 4 and the freewheel 3 to be connected, so as to improve the stability of the rear wheel hub structure, it can be seen that the torque transmission between the hub 1 and the transmission rod 4 is realized by arranging the key shaft 2 in the hub 1, the internal space of the hub 1 is reasonably arranged, the one-way engagement between the ratchet part 40 on the outer wall of the transmission rod 4 and the internal teeth 30 in the freewheel 3 is realized, the driving effect of the freewheel 3 driving the transmission rod 4 is realized, the tower is not additionally arranged at the end of the hub 1 to realize the torque transmission, the lightweight effect of the rear wheel hub structure is improved, the torque transmission effect is greatly improved by the cooperation between the entire shaft center of the hub 1 and the key shaft 2, compared with the traditional torque transmission mode through the tower, the torque transmission mode is more stable and reliable, the installation space of the components is compressed, and the torque transmission effect is greatly improved; in order to facilitate the user to drive the freewheel 3 to rotate by pedaling the pedal, the outer wall of the freewheel 3 is further provided with a chain tooth part 31 for connecting the chain of the bicycle.

[0050] In summary, the rear wheel hub structure establishes torque transmission through the key shaft 2 and the transmission rod 4, ensures stable torque transmission, reasonably uses the internal space of the hub 1, makes the structure of the rear wheel hub structure more compact, the whole more lightweight, and the key shaft 2 penetrating the hub 1 can further ensure the strength of the hub 1 itself; the ratchet part 40 provided on the outer wall of the transmission rod 4 and the inner tooth ring 30 in the freewheel 3 achieve one-way engagement, ensure that the rotation of the freewheel 3 can drive the hub 1 to rotate at the same time, and realize the one-way free rotation effect of the freewheel 3 not rotating when the hub 1 rotates.

[0051] Referring to the accompanying drawings Figure 6 , the accompanying drawings Figure 7 , the accompanying drawings Figure 10 , and the accompanying drawings Figure 11 , the ratchet part 40 includes a ratchet seat 400 and a plurality of pawls 402, the ratchet seat 400 is provided with a plurality of mounting grooves 401 corresponding to the plurality of pawls 402, one end of the pawl 402 is rotatably connected with the mounting groove 401, the other end of the pawl 402 can extend out of the mounting groove 401 and engage with the inner tooth ring 30, the mounting groove 401 is provided with an elastic element 403 abutting against the back of the pawl 402, the compression direction of the elastic element 403 is the same as the rotation direction of the transmission rod 4, specifically, the inner tooth ring 30 in the freewheel 3 is provided with a plurality of teeth 301 engaging with the pawls 402, in this embodiment, the number of teeth 301 is greater than the number of pawls 402, and the number of pawls 402 is preferably four, the fewer pawls 402 can reduce weight and resistance while ensuring the rotation speed of the transmission rod 4; the teeth 301 are inclined tooth structures, so that when the freewheel 3 rotates forward, the transmission rod 4 can be driven to rotate together through the engagement of the teeth 301 and the other end of the pawl 402, and when the transmission rod 4 rotates forward, due to the inclined tooth structure of the teeth 301, the pawl 402 is pressed by the teeth 301 to swing in the direction of the inside of the mounting groove 401, and cannot drive the freewheel 3 to rotate together, thereby realizing the one-way rotation effect of the freewheel 3 and the transmission rod 4.

[0052] In the embodiment, in order to facilitate installation of the claw 402 and achieve that the other end of the claw 402 is outside the installation slot 401 when not under force for engagement with the teeth 301 of the inner tooth ring 30, a concave slot 401a is arranged at one end of the installation slot 401, and a right-angle slot 401b is arranged at the end of the installation slot 401 away from the concave slot 401a, one end of the claw 402 is provided with a connecting cylinder 402a matched with the concave slot 401a, and the other end of the claw 402 can swing around the connecting cylinder 402a through the rotational connection of the connecting cylinder 402a and the concave slot 401a, and in order to ensure that the other end of the claw 402 is outside the installation slot 401, the elastic member 403 is an L-shaped spring piece, the L-shaped spring piece includes a supporting section 403a and a deformed section 403b, the supporting section 403a is fixedly attached in the right-angle slot 401b, and the deformed section 403b is attached to the back of the claw 402, wherein the included angle between the deformed section 403b and the supporting section 403a is 60 degrees, and the acute angle between 50 and 90 degrees can ensure the elasticity of the deformed section 403b and the supporting effect of the L-shaped spring piece on the claw 402, the L-shaped spring piece is installed through the close attachment of the supporting section 403a and the right-angle slot 401b under the action of the spring piece, the stability of the L-shaped spring piece is improved, the form of the L-shaped spring piece can reduce the machining of the claw 402 and the ratchet seat 400, and the overall structural strength is improved, the L-shaped spring piece of the embodiment is made of precision forged steel and has high strength and elasticity, and in other embodiments, the elastic member 403 can also be selected from elastic structures such as compression springs and tension springs.

[0053] Referring to the accompanying drawings Figure 3 , the accompanying drawings Figure 5 , and the accompanying drawings Figure 11, the transmission rod 4 is respectively provided with an inner end connecting portion 43 and an outer end connecting portion 44 on both sides of the ratchet portion 40; the rear wheel hub structure further comprises a transmission assembly 7, the transmission assembly 7 comprises a first inner bearing 71, a second inner bearing 72, a first outer bearing 73 and a limiting ring 70; the limiting ring 70 is arranged in the cavity of the flywheel 3, and the limiting ring 70 is in threaded connection with the outer end connecting portion 44; the limiting ring 70 can abut against the side wall of the inner tooth ring 30 to limit the axial movement of the transmission rod 4 and the flywheel 3, and the limiting ring 70 is connected with the inner wall of the cavity of the flywheel 3 through the first inner bearing 71; the second inner bearing 72 is sleeved on the inner end connecting portion 43 of the transmission rod 4, and the inner end connecting portion 43 is connected with the inner wall of the cavity of the flywheel 3 through the second inner bearing 72; the second inner bearing 72 and the first inner bearing 71 are distributed on both sides of the ratchet portion 40; specifically, the inner tooth ring 30 is distributed at the middle position of the cavity of the flywheel 3, that is, both ends of the inner wall of the cavity of the flywheel 3 are used for cooperating with the first inner bearing 71 and the second inner bearing 72, so as to improve the compactness and stability of the rear wheel hub structure; through the first inner bearing 71 and the second inner bearing 72, it is ensured that the transmission rod 4 can stably rotate in the cavity of the flywheel 3, and the cooperation of the ratchet portion 40 and the inner tooth ring 30 ensures that the rotation of the flywheel 3 can drive the rotation of the transmission rod 4; in order to avoid the misalignment of the axial movement of the transmission rod 4 and the flywheel 3, the outer end connecting portion 44 of the transmission rod 4 is provided with the limiting ring 70; in order to facilitate the connection of the flywheel 3 and the frame 8, and avoid the installation of the frame 8 from interfering with the rotation of the flywheel 3, the first outer bearing 73 is sleeved on the outer wall of the flywheel 3 in the embodiment.

[0054] In order to ensure that the key shaft 2 away from one end of the transmission rod 4 can realize stable support and rotation, the outer connecting assembly 6 is arranged at the end of the hub 1 in the embodiment, as shown in FIGS. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 and 13. Figure 2 , FIGS. Figure 3 and FIGS. Figure 5 The outer connecting assembly 6 comprises an outer connecting piece 60 and a second outer bearing 61; the inner portion of the outer connecting piece 60 is provided with a limiting hole 600 and a third connecting hole 601 which are coaxially communicated; the inner diameter of the limiting hole 600 is greater than that of the third connecting hole 601; the cross section of the third connecting hole 601 is the same as that of the key shaft 2; the end portion of the key shaft 2 is provided with an end cap 20 which is arranged in the limiting hole 600; the end cap 20 of the key shaft 2 is connected with the limiting hole 600, and the end wall of the outer connecting piece 60 abuts against the end portion of the hub 1, so as to avoid the axial misalignment of the key shaft 2 and the outer connecting piece 60; the cooperation of the third connecting hole 601 and the key shaft 2 means that the rotation of the key shaft 2 can drive the rotation of the outer connecting piece 60; in order to facilitate the connection of the outer connecting piece 60 and the frame 8 while the outer connecting piece 60 can rotate relative to the frame 8, the second outer bearing 61 is sleeved on the outer wall of the outer connecting piece 60.

[0055] Referring to FIGS. Figure 3The rear wheel hub structure further comprises brake pads 9, and each end of the hub 1 is provided with a fixing hole for mounting the brake pads 9. Specifically, the brake pads 9 can be mounted at any end of the hub 1 according to actual conditions. The brake pads 9 are mounted at the end of the hub 1 through a transfer disc, and the brake pads 9 are matched with the brake of the bicycle to realize the braking of the hub 1.

[0056] Referring to the drawings Figure 1 The drawings Figure 5 The embodiment further provides a bicycle comprising the rear wheel hub structure, a frame 8, two inner side sealing rings 81 and outer side sealing rings 82. The frame 8 is provided with two connecting cavities 80, and the frame 8 is a Y-shaped fork pipe structure. The two connecting cavities 80 are respectively arranged at the two ends of the Y-shaped fork pipe. Specifically, one connecting cavity 80 of the frame 8 is connected with the freewheel 3 through the first outer bearing 73, and the other connecting cavity 80 of the frame 8 is connected with the external component 60 through the second outer bearing 61. The connecting cavity 80 for connecting the freewheel 3 is a stepped cavity with one side having a large inner diameter and the other side having a small inner diameter. The cavity with the large inner diameter is used for accommodating the first outer bearing 73, and the cavity with the small inner diameter is used for mounting the inner side sealing ring 81 and a sealing ring 83 mounted on the outer wall of the inner side sealing ring 81. The sealing ring 83 and the inner side sealing ring 81 can effectively prevent sand, soil, mud and the like from entering the inside of the connecting cavity 80 through the inner side of the connecting cavity 80 to interfere with the normal operation of the first outer bearing 73, the transmission rod 4 and other components, thereby improving the service life. The connecting cavity 80 with the stepped cavity is arranged so that the first outer bearing 73 and the end of the freewheel 3 form axial limiting of this part of the frame 8, thereby preventing the frame 8 from being separated from this end of the hub 1 and improving the stability of the bicycle using the rear wheel hub structure. In order to ensure the rotation of the transmission rod 4, the transmission rod 4 and the inner side sealing ring 81 have a gap. Similarly, another inner side sealing ring 81 and a corresponding sealing ring 83 are arranged at the inner end of the other connecting cavity 80, thereby effectively improving the sealing effect of the inside of the external component 6. The two inner side sealing rings 81 are arranged between the frame 8 and the hub 1, thereby improving the connection stability and firmness between the frame 8 and the hub 1.

[0057] In order to further improve the sealing effect of the inside of the external component 6 and the connection stability of the frame 8 at the end of the hub 1 provided with the external component 6, the outer side sealing ring 82 is fixedly connected with the external component 60 in the embodiment, and a sealing ring 83 is arranged between the inner wall of the outer side sealing ring 82 and the outer wall of the external component 60. The outer side sealing ring 82 of the embodiment is a T-shaped ring structure, so that the convex ring part of the outer side sealing ring 82 abuts against the outer side of the frame 8 after the outer side sealing ring 82 is connected with the external component 60, thereby limiting the axial movement of the frame 8. The outer wall of the outer side sealing ring 82 and the inner wall of the connecting cavity 80 have a gap, thereby avoiding the interference of the outer side sealing ring 82 with the rotation of the key shaft 2.

[0058] In conclusion, the rear wheel hub structure provided by the embodiment is installed on the frame of the bicycle, and the rear wheel transmission of the bicycle is fully sealed through the multiple sealing rings and the structural layout of the rear wheel hub structure itself.

[0059] Obviously, the above-described embodiments are only a part of the embodiments of the present application, rather than all the embodiments, and the preferred embodiments of the present application are given in the drawings, but do not limit the patent scope of the present application. The present application can be realized in many different forms, and conversely, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing specific embodiments, or equivalently replace some of the technical features. Any equivalent structure made by using the content of the present application specification and drawings, directly or indirectly applied to other related technical fields, is also within the patent protection scope of the present application.

Claims

1. A rear wheel hub structure, characterized in that, The utility model relates to a rear wheel hub structure of a bicycle, which comprises a hub, a key shaft, a flywheel, a transmission rod and an external assembly. The key shaft is coaxially inserted through the shaft center of the hub and is fixed in the circumferential direction of the hub. The outer wall of the transmission rod is provided with a ratchet part. The flywheel is provided with a chain tooth part on the outer wall and a cavity in the inner part. The ratchet part comprises a ratchet seat and a plurality of pawls.

2. The rear wheel hub structure according to claim 1, wherein The one end of the pawl is rotatably connected with the installation slot.

3. The rear wheel hub structure of claim 2, wherein, The other end of the pawl can extend out of the installation slot and engage with the inner tooth ring.

4. The rear wheel hub structure according to claim 3, wherein The installation slot is provided with a concave slot at one end.

5. The rear wheel hub structure of claim 2, wherein The one end of the pawl is provided with a connecting cylinder matched with the concave slot. The installation slot is provided with a right-angle slot at the end away from the concave slot.

6. The rear wheel hub structure of claim 5, wherein The elastic member is fixed in the right-angle slot and connected with the pawl at one end.

7. The rear wheel hub structure of claim 6, wherein The shaft center of the hub is provided with a first connecting hole penetrating through both ends. The one end of the transmission rod is provided with a second connecting hole connected with the key shaft. The cross section of the first connecting hole and the cross section of the second connecting hole are the same as the cross section of the key shaft. The key shaft is hollow.

8. The rear wheel hub structure of claim 5, wherein, The transmission rod is provided with a threaded hole coaxial with the second connecting hole. The one end of the fixing screw rod is sequentially inserted through the key shaft, the second connecting hole and then screwed with the threaded hole to limit the axial movement between the transmission rod and the key shaft. The transmission rod is provided with an inner end connecting part and an outer end connecting part at both sides of the ratchet part.

9. The rear wheel hub structure of claim 2, wherein, The transmission assembly comprises a first inner bearing, a second inner bearing, a first outer bearing and a limiting ring.

10. A bicycle comprising the rear wheel hub structure of claim 8, characterized in that, The limiting ring is placed in the cavity of the flywheel and is screwed with the outer end connecting part. The limiting ring can abut against the side wall of the inner tooth ring to limit the axial movement of the transmission rod and the flywheel. The second inner bearing is sleeved on the inner end connecting part of the transmission rod. The first outer bearing is sleeved on the outer wall of the flywheel. The external assembly comprises an external member and a second outer bearing. The internal part of the external member is provided with a coaxial limiting hole and a third connecting hole. The inner diameter of the limiting hole is larger than the inner diameter of the third connecting hole. The cross section of the third connecting hole is the same as the cross section of the key shaft. The end part of the key shaft is provided with an end cap placed in the limiting hole. The second outer bearing is sleeved on the outer wall of the external member. The hub is provided with a fixing hole for installing the brake pad at both ends. The utility model also comprises a frame, two inner side sealing rings and an outer side sealing ring. The frame is provided with two connecting cavities. One connecting cavity of the frame is connected with the flywheel through the first outer bearing. The other connecting cavity of the frame is connected with the external member through the second outer bearing. Two inner sealing rings are respectively arranged at the inner ends of the two connecting cavities, and the outer wall of the inner sealing ring is provided with a sealing ring, and the two inner sealing rings are arranged between the frame and the hub; The outer sealing ring is fixedly connected with the outer connecting piece, and a sealing ring is arranged between the inner wall of the outer sealing ring and the outer wall of the outer connecting piece.

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