Transmission sprocket

Abstract

A transmission sprocket comprises a sprocket main body, an annular shell and a plural of shift assistant rivets. The sprocket main body is made of a first non-metal material, and a plurality of chain teeth and mounting holes are arranged on the radial outer edge of the sprocket main body. The annular shell is made of second non-metal material. The annular shell covers one side of the sprocket main body and surrounds an inner space together with the sprocket main body. The inner space surrounds an axis of the sprocket body. The shift assistant rivets are arranged in the mounting holes. A rib is formed in the inner space of one of the sprocket main body and the annular shell. The rib radially extends from the axis toward the shift assistant rivets, and the rib abuts against the other of the sprocket main body and the annular shell.

Description

[Technical Field]

[0001] This invention relates to a geared sprocket, and more particularly to a transmission geared sprocket in a bicycle that is combined with a chain to transmit power. [Previous Technology]

[0002] Since the invention of the bicycle, its design has undergone many changes, and a gear mechanism has been developed. Since the weight of a bicycle creates an unnecessary energy burden for the rider, how to reduce the weight of the bicycle while maintaining the gear mechanism has become an important issue.

[0003] When reducing the weight of a bicycle, in addition to changing the type of material used in the bicycle frame, the weight can also be reduced by improving the frame structure. Due to the different properties of materials, the original frame structure design may not provide sufficient strength after changing the type of material used in the frame. Therefore, corresponding to the change in the frame material, the design of the parts of the frame structure that are subject to greater stress, namely the gear shifting mechanism, should also be changed accordingly. [Summary of the Invention]

[0004] The present invention provides a transmission gear disc, which has the advantages of being lightweight and having high structural strength.

[0005] To achieve the above advantages, one embodiment of the present invention provides a transmission gear disc, comprising: a gear disc body made of a first non-metallic material, wherein a plurality of chain teeth and at least one mounting hole are provided on the radial outer edge of the gear disc body; an annular shell made of a second non-metallic material, the annular shell covering one side of the gear disc body and together with the gear disc body surrounding an internal space, the internal space surrounding the axis of the gear disc body; an upper chain protrusion disposed in at least one mounting hole of the gear disc body; and one of the gear disc body and the annular shell forming a rib in the internal space, the rib extending radially from the axis toward the upper chain protrusion, and the rib abutting against the other of the gear disc body and the annular shell.

[0006] In one embodiment, the above-mentioned annular housing has a second disk wall relative to the toothed disk body, the second disk wall extending obliquely from the side close to the axis toward the direction away from the axis and gradually approaching the toothed disk body.

[0007] In one embodiment, the second disk wall described above has a stepped structure and has a plurality of first ring portions, each of which extends obliquely from the side close to the axis toward the direction away from the axis and gradually approaches the toothed disk body.

[0008] In one embodiment, the second disk wall further has a second ring portion, which is connected between two adjacent first ring portions and is not parallel to the first ring portions.

[0009] In one embodiment, one of the first ring portions is located at the outer edge of the annular shell.

[0010] In one embodiment, the outer edge of the annular shell has a notch, and the upper chain protrusion passes through the notch.

[0011] In one embodiment, the ribs extend from the toothed disc body and the annular shell respectively and abut against each other.

[0012] In one embodiment, the first non-metallic material and the second non-metallic material are the same material.

[0013] In one embodiment, the first non-metallic material and the second non-metallic material are different materials.

[0014] In one embodiment, the material of the above-mentioned upper chain bump is a non-metallic material.

[0015] Based on the above description, the transmission gear of the present invention reduces weight by providing an internal space between the gear body and the annular housing. Moreover, because a rib extending radially toward the mounting position of the upper chain protrusion is provided in the space, the transmission gear is less likely to deform when the chain presses against the upper chain protrusion during speed change, giving the self-propelled gear the advantages of being lightweight and having high structural strength.

[0016] In order to make the above and other objects, features and advantages of the present invention more apparent and understandable, embodiments are described below in detail with reference to the accompanying drawings.

Implementation Method

[0017] In the following text, the terms used in the description of embodiments of the present invention, such as "upper" and "lower" indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the drawings used. The above terms are only for the convenience of describing the present invention and are not intended to limit the present invention, that is, they do not indicate or imply that the mentioned elements must have a specific orientation or be constructed in a specific orientation. In addition, the terms "first" and "second" mentioned in this specification or the claims are only used to name the elements or distinguish different embodiments or scopes, and are not used to limit the upper or lower limit of the number of elements.

[0018] Figure 1 is an exploded view of the transmission gear disk in one embodiment of the present invention. Figure 2 is an assembled view of the transmission gear disk in Figure 1. Figure 3 is a cross-sectional view of section AA in Figure 1. Figure 4 is a cross-sectional view of section BB in Figure 1. Figure 5 is a back view of the annular shell in Figure 1.

[0019] As shown in Figures 1 to 5, a transmission gear 100 in one embodiment of the present invention includes: a gear body 1, an annular housing 2, and a chain-upping protrusion 3. The gear body 1 is made of a first non-metallic material, and a plurality of chain teeth 1a and mounting holes 113 are provided on the radial outer edge of the gear body 1. The annular housing 2 is made of a second non-metallic material, and the annular housing 2 covers one side of the gear body 1, and together with the gear body 1, surrounds an internal space S, which surrounds the axis A of the gear body 1. The chain-upping protrusion 3 is provided in the mounting hole 113. One of the gear body 1 and the annular housing 2 forms a rib in the internal space S (see ribs 112 and 211 in Figure 3), and ribs 112 and 211 extend radially from the axis A toward the chain-upping protrusion 3, and ribs 112 and 211 abut against the other of the gear body 1 and the annular housing 2.

[0020] In this embodiment, the axis of the transmission gear 100 and the axis of the annular housing 2 also coincide with axis A.

[0021] In this embodiment, the winding bump 3 is, for example, a pin inserted into the toothed disc body 1 and detachable from it. The shape and material of the winding bump 3 are not particularly limited. Specifically, the main function of the winding bump 3 is to provide an additional attachment point between the original toothed disc and the target toothed disc when the chain moves between the toothed discs, thus promoting a smooth winding process. Therefore, it only needs to protrude from the toothed disc surface and have sufficient axial length. The material of the winding bump 3 is, for example, metal, but is not limited thereto. It can also be a non-metallic material such as fiber composite materials or polymer materials that meet the requirements for wear resistance and strength. In embodiments similar to the one in Figure 1, which have multiple winding bumps 3, the shapes of the different winding bumps 3 can be different.

[0022] In this embodiment, the transmission gear 100 further includes, for example, a claw 4, which is used for connecting to, for example, a bicycle crank (not shown) and a secondary gear 5 (see Figure 2). The claw 4 is, for example, cross-shaped, but there are no particular limitations. The center of the claw 4 is located on the axle A and has a connection hole 41 suitable for connecting to the bicycle crank. There are no particular limitations on the material of the claw 4; common materials include steel, iron, fiber composites, polymer composites, aluminum alloys, and titanium alloys, etc., and appropriate materials can be selected according to the requirements of the usage environment.

[0023] As shown in Figure 2, the secondary gear 5 is, for example, a gear with a diameter smaller than that of the drive gear 100. When the secondary gear 5 is combined with the drive gear 100, the secondary gear 5 is, for example, mounted on the side of the drive gear 100 near the bicycle frame (not shown). The material of the secondary gear 5 can be selected according to requirements. In an embodiment not shown, the structure of the secondary gear 5 can be similar to that of the drive gear 100.

[0024] As shown in Figures 1 to 3, the gear disc body 1 is made of a first non-metallic material. The first non-metallic material can be integrally molded from carbon fiber, but is not limited thereto. It can also be other types of fiber composite materials and polymer materials, etc., that meet the strength requirements. When the drive gear disc 100 is combined with the bicycle frame, the gear disc body 1 is, for example, located on the side of the drive gear disc 100 away from the bicycle frame. The gear disc body 1 is, for example, annular and includes a first disc wall 11, a first annular wall 12, and a plurality of fixing parts 13.

[0025] As shown in Figures 1 and 3, continuing from the above, in this embodiment, the first disc wall 11 has a first disc surface 110 on the side facing the annular housing 2 (which in this embodiment is also the side of the disc body 1 facing the bicycle frame). The normal direction of the first disc surface 110 is, for example, parallel to the axis A.

[0026] In this embodiment, the first disk wall 11 has a plurality of grooves 111 with openings on the first disk surface 110, and ribs 112 are formed between each groove 111. The first disk surface 110 is, for example, the bottom surface of the groove 111.

[0027] Continuing from the above, the first disc wall 11 also has a mounting hole 113 suitable for assembly with the upper chain protrusion 3. The mounting hole 113 is located, for example, on the extension line of the rib 112 and next to the groove 111, and closer to the axis A than the chain tooth 1a. The chain tooth 1a of the gear disc body 1 is located, for example, on the outer periphery of the first disc wall 11.

[0028] In this embodiment, the first annular wall 12 is located at the inner periphery of the first disk wall 11. The first annular wall 12 protrudes toward the annular housing 2, for example, from the surface of the first disk surface 110 along an extension direction parallel to the axis A of the transmission gear disk 100. The outer wall surface of the first annular wall 12 (the wall surface of the first annular wall 12 facing away from the axis A) is, for example, perpendicular to the first disk surface 110, but is not limited thereto.

[0029] Subsequently, the fixing part 13 is, for example, a plurality of blocks protruding from the inner wall surface of the first annular wall 12 (the wall surface of the first annular wall 12 facing the axis A) toward the axis A of the transmission gear disk 100. The number of fixing parts 13 corresponds, for example, to the number of the endpoints of the claw part 4, and the shape of the fixing part 13 corresponds, for example, to the shape of the endpoints of the claw part 4.

[0030] When the gear disc body 1 and the claw part 4 are assembled, each end point of the claw part 4 is connected to the fixing part 13 of the gear disc body 1. The connection method between the fixing part 13 and the claw part 4 is not limited, for example, it can be connected by fastener screwing or by adhesive bonding, etc., and can be set according to requirements. The shape of the gear disc body 1 can be set according to requirements. In the embodiment not shown in the figure, the gear disc body 1 and the claw part 4 can be integrally formed.

[0031] As shown in Figures 1 to 5, specifically, the annular shell 2 is made of a second non-metallic material. This second non-metallic material can be integrally molded from carbon fiber, but is not limited to this; it can also be other fiber composite materials or polymer materials that meet strength requirements. Furthermore, depending on the usage environment, the first and second non-metallic materials can be the same material, and different materials can be selected according to different strength requirements. In this embodiment, the outer diameter and inner diameter of the annular shell 2 are, for example, smaller than the outer diameter and inner diameter of the gear disc body 1, respectively. When installed, the annular shell 2 is, for example, located on the side of the drive gear disc 100 close to the bicycle frame relative to the gear disc body 1. The annular shell 2 is, for example, annular in shape. The annular shell 2 includes a second disc wall 21 that is annular in shape and a second annular wall 22 located at the inner edge of the annular shell 2.

[0032] As shown in Figures 1 to 5, in this embodiment, the second disk wall 21 has a second disk surface 210 on the side facing the toothed disk body 1. The second disk wall 21 extends obliquely from the side of the second annular wall 22 away from the toothed disk body 1, from the side close to the axis A toward the direction away from the axis A, and gradually approaches the toothed disk body 1. The size of the second disk wall 21 is such that, when the toothed disk body 1 and the annular housing 2 are combined, it can completely cover the size of each groove 111 on the toothed disk body 1.

[0033] As shown in Figures 2 and 3, in this embodiment, the second disk wall 21 has, for example, a stepped structure, and a stepped surface is formed on one side opposite to the second disk surface 210. The second disk wall 21 with the stepped structure has a plurality of first ring portions 212 and a plurality of second ring portions 213. For example, there are three first ring portions 212, and one of the first ring portions 212 is located at the outer edge of the annular housing 2. Each first ring portion 212 extends obliquely from the side near the axis A toward the direction away from the axis A and gradually approaches the side of the annular housing 2 near the toothed disk body 1. The inclination angles of the different first ring portions 212 can be different. For example, in this embodiment, the inclination angle of the first ring portion 212 located at the outer edge of the annular housing 2 is greater than the inclination angles of the other two first ring portions 212.

[0034] As shown in Figures 2 and 3, there are, for example, two second ring portions 213. Each second ring portion 213 is connected between two adjacent first ring portions 212, and the extending direction of the second ring portion 213 is not parallel to the extending direction of the first ring portion 212. In this embodiment, on one side surface opposite to the second disc surface 210, the surfaces of the different second ring portions 213 are, for example, parallel to each other and facing the extending direction of the axis A, but are not limited thereto. With this configuration, when the bicycle with the drive chain 100 is shifting gears, the chain (not shown) can gradually move along the surface of the second disc wall 21 away from the disc body 1 in the extending direction of the axis A.

[0035] Since the present invention does not limit the shape of the second disk wall 21, in other embodiments of the present invention, the stepped structure can be replaced with a continuous curved surface structure or an inclined structure. This allows the chain (not shown) to move gradually along the second disk wall 21 in the extension direction of the axis A.

[0036] As shown in Figure 3, the second annular wall 22 extends, for example, from the inner edge of the second disk surface 210 along the extension direction parallel to the axis A of the transmission gear disk 100 toward the side where the gear disk body 1 is located, and is suitable to contact the first annular wall 12 when the annular housing 2 and the gear disk body 1 are combined.

[0037] As shown in Figure 3, during assembly, the first annular wall 12 and the second annular wall 22 are in contact with each other, and the portion of the first disk wall 11 near its outer periphery is also in contact with the outer periphery of the second disk wall 21. In this embodiment, the inner wall surface of the second annular wall 22 (the wall surface of the second annular wall 22 facing the side closest to axis A) is attached to the outer wall surface of the first annular wall 12. Therefore, the internal space S is jointly formed by the first disk surface 110, the second disk surface 210, and the second annular wall 22, but this can be configured according to requirements. As can be seen from Figure 3, the distance between the first disk surface 110 and the second disk surface 210 gradually decreases radially away from axis A from the first annular wall 12.

[0038] As shown in Figure 3, the detailed connection method between the toothed disc body 1 and the annular housing 2 can be set according to the requirements. For example, the contact parts of the toothed disc body 1 and the annular housing 2 can be melted by heating and joined together, or an adhesive can be provided between the two.

[0039] Since there is no particular limitation on the size relationship between the annular shell 2 and the toothed disc body 1, the internal space S can be formed by the first disc surface 110, the second disc surface 210 and the first annular wall 12 in an embodiment not shown in the figure, based on the relative size relationship between the first annular wall 12 and the second annular wall 22.

[0040] As shown in Figures 2, 4 and 5, in this embodiment, the outer edge of the annular shell 2 has a notch 211a that penetrates the annular shell 2 along the direction parallel to the axis A. When assembling the components, the upper chain protrusion 3 passes through the notch 211a and is detachably inserted into the mounting hole 113 of the gear plate body 1. With this structure, after assembly, the upper chain protrusion 3 protrudes from the surface of the outermost first ring portion 212, which is suitable for assisting the chain and chain teeth 1a in engagement during speed change.

[0041] The size of the winding bump 3 can be set according to requirements. For example, as shown in Figures 2 and 4, in this embodiment, when the winding bump 3 is provided on the toothed disc body 1, in the direction parallel to the extension direction of the axis A, the winding bump 3 not only protrudes from the surface of the first ring portion 212 located on the outer edge of the annular housing 2, but also protrudes from the surface of the second ring portion 213 located near the outer edge of the annular housing 2.

[0042] As shown in Figures 2 and 4, in this embodiment, because the upper chain protrusion 3 has a mushroom-shaped shape, in the radial direction of the transmission gear disk 100, the upper chain protrusion 3 not only partially covers the surface of the first ring portion 212 at the outermost edge of the annular housing 2, but also covers the surface adjacent to the second ring portion 213, and does not cover the surface of other first ring portions 212.

[0043] As shown in Figures 3 and 5, in this embodiment, the gear disk body 1 and the annular housing 2 each form opposing ribs 112 and 211 on the side facing the internal space S. These ribs (ribs 112 and 211) extend radially along the transmission gear disk 100 and abut against each other when the gear disk body 1 and the annular housing 2 are connected. The internal space S is divided into multiple sub-chambers through these ribs (ribs 112 and 211).

[0044] Regarding the ribs in the internal space S, specifically, as shown in FIG1, the ribs 112 of the toothed disc body 1 are formed, for example, between two grooves 111 of the first disc wall 11, and the top surface of the ribs 112 is aligned, for example, with the first disc surface 110. As shown in FIG5, the ribs 211 of the annular shell 2 are formed, for example, between the second disc surface 210 and the second annular wall surface, and are opposite to each other, for example, corresponding to the position of the ribs 112 of the toothed disc body 1.

[0045] It should be understood that the detailed shapes of ribs 112 and 211 can be set according to requirements. For example, in an embodiment not shown in the figures, the toothed disc body 1 may not have grooves 111 and may not have ribs 112, so that the ribs 211 of the annular housing 2 directly abut against the first disc surface 110. In another embodiment, the annular housing 2 may not have ribs 211, and the ribs 112 of the toothed disc body 1 may protrude from the first disc surface 110 and abut against the second disc surface 210 when the toothed disc body 1 and the annular housing 2 are combined.

[0046] Based on the above description, the transmission gear of the present invention reduces weight by providing an internal space between the gear body and the annular housing. Furthermore, because a rib extending radially toward the location of the upper chain protrusion is provided in the space, the transmission gear is less likely to deform when the chain presses against the upper chain protrusion during gear shifting. This gives the bicycle gear the advantages of being lightweight and having high structural strength.

[0047] In addition, because the annular shell has a stepped structure, the chain can move gradually along the surface of the annular shell during speed change, and smoothly engage with the teeth of the gear disc body after passing the upper chain protrusion.

[0048] Although the present invention has been disclosed above by way of embodiments, it is not intended to limit the present invention. Those skilled in the art to which the present invention pertains may make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims. [Simplified Explanation of the Diagram]

[0049] Figure 1 is an exploded view of the transmission gear disk in one embodiment of the present invention; Figure 2 is an assembled view of the transmission gear disk in Figure 1; Figure 3 is a cross-sectional view of section AA in Figure 1; Figure 4 is a cross-sectional view of section BB in Figure 1; Figure 5 is a back view of the annular shell in Figure 1.

Claims

1. A transmission gear disc, comprising: A toothed disc body is made of a first non-metallic material, and the radial outer edge of the toothed disc body is provided with a plurality of chain teeth and at least one mounting hole; an annular shell is made of a second non-metallic material, the annular shell covers one side of the toothed disc body, and together with the toothed disc body, forms an internal space, the internal space surrounding an axis of the toothed disc body; a chain-up protrusion is disposed in the at least one mounting hole; wherein, one of the toothed disc body and the annular shell forms a rib in the internal space, the rib extending radially from the axis toward the chain-up protrusion, and the rib abuts against the other of the toothed disc body and the annular shell; wherein, the annular shell has a second disc wall relative to the toothed disc body, the second disc wall extending obliquely from the side close to the axis toward a direction away from the axis and gradually approaching the toothed disc body.

2. The transmission gear disk as claimed in claim 1, wherein the second disk wall has a stepped structure and has a plurality of first ring portions, each of the first ring portions extending obliquely from a side close to the axis toward a direction away from the axis and gradually approaching the gear disk body.

3. The transmission gear disc as claimed in claim 2, wherein the second disc wall further has at least one second ring portion connected between two adjacent first ring portions and not parallel to the first ring portions.

4. The transmission gear disc as claimed in claim 2, wherein one of the first ring portions is located at the outer edge of the annular housing.

5. The drive gear as claimed in claim 1, wherein the outer edge of the annular housing has at least one notch through which the upper chain protrusion passes.

6. The transmission gear as claimed in claim 1, wherein the ribs extend opposite to each other from the gear body and the annular housing and abut against each other.

7. The transmission gear disc as claimed in claim 1, wherein the first non-metallic material and the second non-metallic material are the same material.

8. The transmission gear disc as claimed in claim 1, wherein the first non-metallic material and the second non-metallic material are different materials.

9. The drive gear as claimed in claim 1, wherein the upper chain protrusion is made of a non-metallic material.

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