Bicycle hub transmission structure

Abstract

A bicycle hub transmission structure comprises a hub body, an end of which is formed with an open accommodating space, wherein the centre of accomrnodating space is transfixed with a central shaft, th

Description

BACKGROUND OF THE INVENTION (a) Field of the Invention The present invention relates to a bicycle hub transmission structure, and more particularly to a bicycle hub transmission structure which is equipped with a vibration reduction effect and a light-weight effect. (b) Description of the Prior Art A conventional bicycle hub structure was published in a Taiwanese Patent No. M544397, “HUB DRIVING STRUCTURE,” on July 1, 2017 and applied by the present inventor on January 6, 2017. The hub driving structure includes a hub body, which is axially transfixed with a spindle, wherein an end of the hub body is formed with an open assembly space, an interior of the assembly space is fixed with a linkage ring, and an outer surface of the linkage ring is provided with an annular linkage gear; a sprocket sleeve, which fits with and is assembled on the spindle of the hub body, wherein a side end facing the hub body is formed with an open assembly slot, an inner circumference of the assembly slot is sequentially arranged with plural embedding teeth to fit and engage with a drive ring, an outer periphery of the drive ring is provided sequentially with a locking teeth to gnaw and fix with the embedding teeth of the assembly slot, and an outer surface of the drive ring is provided with an annular drive gear. It is not hard to find out there are still some shortcomings by carefully reviewing the abovementioned conventional structures, mainly contributing to that both the conventional linkage ring and drive ring are formed with a perforation at center, and both are sheathed on the spindle of the hub body; however, as the linkage ring and the drive ring are all made of metallic materials, and are manufactured with heavy materials in consideration of strength, the entire hub structure is heavy, which lacks the light-weight effect thereby affecting velocity and smoothness in cycling. On the other hand, both the linkage ring and drive ring do not have the structure and the effect of vibration reduction and buffering; therefore, the vibration generated in cycling will be transmitted directly to the linkage ring and the drive ring, which can easily result in jumping and teeth disengagement between the linkage ring and the drive ring by vibration. In addition, the linkage ring and the drive ring can be even damaged by constant friction and impact, thereby significantly reducing the operational stability of the hub. SUMMARY OF THE INVENTION The present invention is to provide a bicycle hub transmission structure to solve the abovementioned shortcomings existing in the prior art. The bicycle hub transmission structure comprises a hub body, an end of which is formed with an open accommodating space, wherein the center of the accommodating space is axially penetrated with a central shaft, the accommodating space is installed with a linkage ring, the linkage ring is fixed inward in the accommodating space along the central shaft, and an end surface on the linkage ring is provided with a linkage ring teeth; and a sprocket base, which is assembled with the hub body along the central shaft for operation, wherein an end of the sprocket base is concaved with a mating space, the mating space is axially assembled with a drive ring, an end of the drive ring is concaved inward with an assembly groove, the center on the other end of the drive ring is provided with a perforation, the inner diameter of the perforation is smaller than the inner diameter of the assembly groove, a baffle wall is formed opposite to the assembly groove, the assembly groove is tightly assembled with a first shock-absorbing ring made of light materials, and an outer surface of the baffle wall is provided with a drive ring teeth to engage and disengage the linkage ring teeth of the linkage ring. Preferably, an end of the first shock-absorbing ring is protruded with a locking portion along the center. The outer diameter of the locking portion is smaller than the outer diameter of the first shock-absorbing ring. The locking portion penetrates from an end away from the baffle wall, and the first shock-absorbing ring is positioned and links with a spring through the locking portion. Preferably, an end of the linkage ring is concaved inward with a coupling groove. The coupling groove is tightly assembled with a second shock-absorbing ring made of light materials, and the center on the other end of the linkage ring is provided with a through hole. The inner diameter of the through hole is smaller than the inner diameter of the coupling groove, the linkage ring is formed with a retaining edge opposite to the coupling groove, and an outer surface of the retaining edge is provided with the said linkage ring teeth. Preferably, the coupling groove is a stepped groove and is equipped with a large-diameter section and a small-diameter section. The inner diameter of the through hole is smaller than the inner diameter of the large-diameter section and the inner diameter of the small-diameter section. In addition, an end of the second shock-absorbing ring is protruded with an engaging portion along the center; whereas, the engaging portion is tightly assembled with the small-diameter section, and tightly assembles the second shock-absorbing ring to the large-diameter section. Preferably, the outer periphery of the retaining edge of the linkage ring is formed with a non-cylindrical tool protrusion. The linkage ring is fixed in the accommodating space by a threaded locking method, wherein the outer circumference of the linkage ring is provided with an external threaded section, a tail end of the external threaded section is further extended with a flat section, and the flat section abuts against an inner surface of the accommodating space to improve the stability of the linkage ring. In comparison to the prior art, the first shock-absorbing ring is used to mitigate and counteract the vibration to the drive ring in cycling, and to allow the drive ring to utilize the fact that the first shock-absorbing ring is actually assembled on the central shaft along the center, so as to improve the stability of the drive ring. Furthermore, the object of light-weight is achieved by the light materials of the first shock-absorbing ring. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a three-dimensional view of the present invention. FIG. 2 shows an exploded view of the present invention. FIG. 3 shows an exploded blowup view of a drive ring, a linkage ring, a first shock-absorbing ring and a second shock-absorbing ring, according to the present invention. FIG. 4 shows a cutaway view of assembly of the present invention. FIG. 5 shows a locally enlarged cutaway view of assembly of the present invention. FIG. 6 shows a blowup view of another embodiment of the drive ring, the linkage ring, the first shock-absorbing ring and the second shock-absorbing ring, according to the present invention. FIG. 7 shows a locally enlarged cutaway view of another embodiment of assembly of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 to 5, a bicycle hub transmission structure comprises a hub body 10, an end of which is formed with an open accommodating space 11, wherein the center of the accommodating space 11 is axially transfixed with a central shaft 12, the accommodating space 11 is installed with a linkage ring 13, the linkage ring 13 is fixed inward in the accommodating space 11 along the central shaft 12 with the linkage ring 13 being fixed in the accommodating space 11 by a threaded locking method in the present embodiment, an outer circumference of the linkage ring 13 is provided with an external threaded section 131, a tail end of the external threaded section 131 is further extended with a flat section 131, the flat section 131 abuts against an inner surface of the accommodating space 11 to improve the stability of the linkage ring 13, and an outward end surface of the linkage ring 13 is provided with a linkage ring teeth 133; and a sprocket base 20, which is assembled with the hub body 10 along the central shaft 12, wherein an end of the sprocket base 20 is concaved with a mating space 21, the mating space 21 is axially assembled with a drive ring 22, an inner circumference of the mating space 21 is provided with a mating ring teeth 211, an outer periphery of the drive ring 22 is provided with a coupling ring teeth 221 to gnaw and position with the mating ring teeth 211, the mating ring teeth 221 and the coupling ring teeth 221 are protruded and formed along the central shaft 12 that the linkage ring 22 can displace axially in the mating space 21, an end of the drive ring 22 is concaved inward with an assembly groove 222, the center on the other end of the drive ring 22 is provided with a perforation 223, the inner diameter of the perforation 223 is smaller than the inner diameter of the assembly groove 222, the perforation 223 is formed with a baffle wall 224 opposite to the assembly groove 222, the assembly groove 222 is tightly assembled with a first shock-absorbing ring 23 made of light materials, and an outer surface of the baffle wall 224 is provided with a drive ring teeth 225 to engage and disengage the linkage ring teeth 133 of the linkage ring 13. Accordingly, the first shock-absorbing ring 23 is used to mitigate and counteract the vibration to the drive ring 22 in cycling, and to allow the drive ring 22 to utilize the fact that the first shock-absorbing ring 23 is actually assembled on the central shaft 12 along the center, thereby improving the stability of the linkage ring 22. In addition, the object of light-weight is achieved by the light materials of the first shock-absorbing ring 23. Furthermore, an end of the linkage ring 13 is concaved inward with a coupling groove 134, and the coupling groove 134 is tightly assembled to a second shock-absorbing ring 14 made of light materials. The center on the other end of the linkage ring 13 is provided with a through hole 135, the inner diameter of the through hole 135 is smaller than the inner diameter of the coupling groove 134, and the linkage ring 13 is formed with a retaining edge 136 opposite to the coupling groove 134. An outer surface of the retaining edge 136 is provided with the linkage ring teeth 133, and an outer periphery of the retaining edge 136 is formed with a non-cylindrical tool protrusion 137 for sheathing with a wrench or sleeve. Accordingly, the second shock-absorbing ring 14 is used to mitigate and counteract the vibration of the linkage ring 13, so as to improve the stability of the linkage ring 13. In addition, the object of light-weight is achieved by the light materials of the second shock-absorbing ring 14. The said first shock-absorbing ring 23 and second shock-absorbing ring 24 are made of plastic or rubber. Referring to FIG. 6 and FIG. 7 for another embodiment of the structure, an end of the first shock-absorbing ring 23 is protruded with a locking portion 231 along the center. The outer diameter of the locking portion 231 is smaller than the outer diameter of the first shock-absorbing ring 23, the locking portion 231 penetrates from an end away from the baffle wall 224, and is positioned and links with a spring 24, so that the spring 24 can actually push the drive ring 22 to displace axially, thereby improving the stability of engagement and disengagement of the drive ring 22. The coupling groove 134 is a stepped groove and is provided with a large-diameter section 1341 and a small-diameter section 1342. The inner diameter of the through hole 135 is smaller than the inner diameter of the large-diameter section 1341 and the inner diameter of the small-diameter section 1342. In addition, an end of the second shock-absorbing ring 14 is protruded with an engaging portion 141 along the center, the engaging portion 141 is tightly assembled with the small-diameter section 1342, and tightly assembles the second shock-absorbing ring 14 to the large-diameter section 1341, so as to actually fix the second shock-absorbing ring 14 in 5 the coupling groove 134 of the linkage ring 13 stably, which is also equipped with a strong structure under the light-weight requirement.

Claims

1. A bicycle hub transmission structure comprising:a hub body, an end of which is formed with an open accommodating space, wherein the center of accommodating space is axially penetrated with a central shaft, the accommodating space is installed with a linkage ring, the linkage ring is fixed inward in the accommodating space along the central shaft, and an outer surface of the linkage ring is provided with a linkage ring teeth; anda sprocket base, which is assembled with the hub body along the central shaft, wherein an end of the sprocket base is concaved with a mating space, the mating space is axially assembled with a drive ring, an end of the drive ring is concaved inward with an assembly groove, the center on the other end of the drive ring is provided with a perforation, the inner diameter of the perforation is smaller than the inner diameter of the assembly groove, the perforation is formed with a baffle wall opposite to the assembly groove, the assembly groove is tightly assembled with a first shock-absorbing ring made of light materials, and an outer surface of the baffle wall is provided with a drive ring teeth to engage and disengage the linkage ring teeth of the linkage ring;accordingly, the first shock-absorbing ring being used to mitigate the vibration of the drive ring to improve the stability of the drive ring, and the object of light-weight being achieved by the light materials of the first shock-absorbing ring.

2. The bicycle hub transmission structure according to claim 1, wherein an end of the first shock-absorbing ring is protruded with a locking portion along the center, the outer diameter of the locking portion is smaller than the outer diameter of the first shock-absorbing ring, and the locking portion penetrates from an end away from the baffle wall, and is positioned and links with a spring.

3. The bicycle hub transmission structure according to claim 1, wherein an end of the linkage ring is concaved inward with a coupling groove, the coupling groove is tightly assembled with a second shock-absorbing ring made of light materials, the center on the other end of the linkage ring is provided with a through hole, the inner diameter of the through hole is smaller than the inner diameter of the coupling groove, the linkage ring is formed with a retaining edge opposite to the coupling groove, and an outer surface of the retaining edge is provided with the linkage ring teeth.

4. The bicycle hub transmission structure according to claim 3, whereinthe first shock-absorbing ring and the second shock-absorbing ring are made of plastic or rubber.

5. The bicycle hub transmission structure according to claim 3, wherein the coupling groove is a stepped groove and is provided with a large-diameter section and a small-diameter section, the inner diameter of the through hole is smaller than the inner diameter of the large-diameter section and the inner diameter of the small-diameter section, an end of the second shock-absorbing ring is protruded with a locking portion along the center, the locking portion is tightly assembled with the small-diameter section and tightly assembles the second shock-absorbing to the large-diameter section.

6. The bicycle hub transmission structure according to claim 3, wherein an outer periphery of the retaining edge of the linkage ring is formed with a non-cylindrical tool protrusion.

7. The bicycle hub transmission structure according to claim 1, wherein the linkage ring is fixed in the accommodating space by a threaded locking method, the outer circumference of the linkage ring is provided with an external threaded section, a tail end of the external threaded section is further extended with a flat section, and the flat section abuts against an inner surface of the accommodating space,so as to improve the stability of the linkage ring.