TWI754119B - Bicycle sprocket assembly - Google Patents

Abstract

A bicycle sprocket assembly having a rotational center axis is provided. The bicycle sprocket assembly comprises a first sprocket and a second sprocket. The first sprocket includes first teeth, a first sprocket body and a first engagement portion. The first sprocket body includes a central portion, a radially outer portion and an intermediate portion disposed between the central portion and the radially outer portion in a radial direction with respect to the rotational center axis of the bicycle sprocket assembly. The first teeth are formed along a radially outer periphery of the radially outer portion. The central portion has a torque transmitting profile engaged with at least one of a crank arm and a crank axle to transmit a pedaling torque from the crank arm to the first teeth. The first engagement portion is disposed on the first sprocket body. The second sprocket includes second teeth, a second sprocket body and a second engagement portion. The second sprocket body is formed with the second teeth along a radially outer periphery of the second sprocket body. The second engagement portion is disposed on the second sprocket body and engaged with the first engagement portion to position the second sprocket with respect to the first sprocket in at least one of a circumferential direction and the radial direction of the bicycle sprocket assembly with respect to the rotational center axis in an assembled state where the second sprocket is attached to the first sprocket.

Description

bicycle sprocket assembly

The present invention relates to a bicycle sprocket assembly.

Cycling is becoming a popular form of recreation as well as a means of transportation. One type of bicycle sprocket assembly is a direct mount bicycle sprocket assembly. A direct mount bicycle sprocket assembly includes sprockets, wherein one of the sprockets includes a central portion, a radially outer portion and is disposed in a radial direction relative to a central axis of rotation of the bicycle sprocket assembly an intermediate portion between the central portion and the radially outer portion. A defining feature of the direct mount bicycle sprocket assembly is that the central portion has a peg groove that engages with at least one of a crank arm and a crank axle to transmit a pedaling torque. A direct mount bicycle sprocket assembly typically employs screws to secure the sprockets together and transmit pedaling torque between the sprockets. However, the screws securing the sprockets will become loose with long-term reciprocating pedaling torque.

According to a first aspect of the present invention, a bicycle sprocket assembly having a central axis of rotation includes a first sprocket and a second sprocket. The first sprocket includes first teeth, a first sprocket body and a first engaging portion. The first sprocket body includes a central portion, a radially outer portion, and is disposed between the central portion and the radially outer portion in a radial direction relative to the central axis of rotation of the bicycle sprocket assembly a middle part. The first teeth are formed along a radially outer periphery of the radially outer portion. The central portion has a torque transfer profile that meshes with at least one of a crank arm and a crank shaft to transfer a pedaling torque from the crank arm to the first teeth. The first engaging portion is disposed on the first sprocket body. The second sprocket includes second teeth, a second sprocket body and a second engaging portion. The second sprocket body is formed with the second teeth along a radially outer periphery of the second sprocket body. The second engaging portion is disposed on the second sprocket body and engages with the first engaging portion in an assembled state in which the second sprocket is attached to the first sprocket to be mounted on the bicycle sprocket The assembly positions the second sprocket relative to the first sprocket in at least one of a circumferential direction and the radial direction relative to the central axis of rotation.

By virtue of the bicycle sprocket assembly according to the first aspect, a fastener securing the second sprocket to the first sprocket can be prevented from loosening because the fastener is not used in the rotation relative to the central axis of rotation. The first sprocket and the second sprocket are oppositely positioned in at least one of the circumferential direction and the radial direction.

According to a second aspect of the present invention, the bicycle sprocket assembly according to the first aspect is configured such that the first engaging portion is formed on the intermediate portion.

With the bicycle sprocket assembly according to the second aspect, the intermediate portion facing the second sprocket in an axial direction with respect to the rotation center axis can be used for a first engaging portion.

According to a third aspect of the present invention, the bicycle sprocket assembly according to the first aspect or the second aspect is configured such that the first engagement portion includes a first radial wall extending in the radial direction And the second engaging portion includes a second radial wall extending in the radial direction, and the first and the second radial wall face each other in the circumferential direction in the assembled state.

With the bicycle sprocket assembly according to the third aspect, the first sprocket and the second sprocket can be positioned in the circumferential direction.

According to a fourth aspect of the present invention, the bicycle sprocket assembly according to the third aspect is configured such that the first radial wall is formed on a circumferential edge of the intermediate portion in the circumferential direction.

With the bicycle sprocket assembly according to the fourth aspect, it is not necessary to process an intermediate portion to form a first engaging portion.

According to a fifth aspect of the present invention, the bicycle sprocket assembly according to the fourth aspect is configured such that the second engagement portion includes a recess in which the second radial wall is formed, and the recess receives the intermediate portion one part.

With the bicycle sprocket assembly according to the fifth aspect, the first sprocket and the second sprocket can be relatively positioned both clockwise and counterclockwise in the circumferential direction.

According to a sixth aspect of the present invention, the bicycle sprocket assembly according to any one of the first to fourth aspects is configured such that the first engaging portion includes a first engaging portion extending in the circumferential direction The circumferential wall and the second engaging portion includes a second circumferential wall extending in the circumferential direction, and the first and second circumferential walls face each other in the radial direction in the assembled state.

According to a seventh aspect of the present invention, the bicycle sprocket assembly according to the sixth aspect is configured such that the first engaging portion includes a first circumferential rib extending in the circumferential direction and the first circumferential A wall is formed on the rib.

According to an eighth aspect of the present invention, the bicycle sprocket assembly according to the seventh aspect is configured such that the second sprocket body includes a cut-out portion on which the second circumferential wall is disposed, And the cut-out portion receives the first circumferential rib in the assembled state.

With the bicycle sprocket assembly according to any one of the sixth to eighth aspects, the first sprocket and the second sprocket can be positioned in the radial direction.

According to a ninth aspect of the present invention, the bicycle sprocket assembly according to the eighth aspect is configured such that the intermediate portion includes a first attachment hole securing the second sprocket to the first sprocket A fastener passes through the hole, and the first circumferential rib is positioned radially inward from the first attachment hole.

According to a tenth aspect of the present invention, the bicycle sprocket assembly according to the ninth aspect is configured such that the second sprocket body includes a second attachment hole through which the fastener passes and the truncated The portion is positioned radially inward from the second attachment hole.

By virtue of the bicycle sprocket assembly according to the ninth aspect or tenth aspect, the first sprocket, which is connected to the second teeth and transmits a torque between the second sprocket body and the second teeth, can be prevented. The strength of the part of the two sprocket bodies is reduced because the part of the second sprocket body connected to the second teeth will be placed in the radially outer part of the second attachment hole with the cutout weaker down.

According to an eleventh aspect of the present invention, the bicycle sprocket assembly according to the sixth aspect is configured such that the second engaging portion includes a second circumferential rib on which the second circumferential wall is formed .

According to a twelfth aspect of the present invention, the bicycle sprocket assembly according to the eleventh aspect is configured such that the first engaging portion includes a recessed portion on which the first circumferential wall is formed , and the recessed portion receives the second circumferential rib in the assembled state.

With the bicycle sprocket assembly according to the eleventh aspect or the twelfth aspect, the first sprocket and the second sprocket can be positioned in the radial direction.

According to a thirteenth aspect of the present invention, the bicycle sprocket assembly according to the twelfth aspect is configured such that the recessed portion is disposed between the intermediate portion and the radially outer portion in the radial direction , and the first sprocket body includes a bridge portion disposed adjacent to the recessed portion in the circumferential direction.

With the bicycle sprocket assembly according to the thirteenth aspect, the first engaging portion around the recessed portion can be reinforced.

According to a fourteenth aspect of the present invention, the bicycle sprocket assembly according to the twelfth or thirteenth aspect is configured such that the intermediate portion includes a first attachment hole, the second sprocket A fastener secured to the first sprocket passes through the hole, and the recessed portion is positioned radially outward from the first attachment hole.

According to a fifteenth aspect of the present invention, the bicycle sprocket assembly according to the fourteenth aspect is configured such that the second sprocket body includes a second attachment hole through which the fastener passes, and the A second circumferential rib is positioned radially outward from the second attachment hole.

With the bicycle sprocket assembly according to the fourteenth aspect or the fifteenth aspect, the first sprocket and the second sprocket can be positioned in the radial direction.

According to a sixteenth aspect of the present invention, the bicycle sprocket assembly according to the sixth aspect is configured such that the first engaging portion includes a protrusion from the intermediate portion, and the protrusion defines the first circumference wall and the first radial wall.

According to a seventeenth aspect of the present invention, the bicycle sprocket assembly according to the sixteenth aspect is configured such that the second engaging portion includes a recess in which the second circumferential wall is formed, and the recess receives the protrusion at least part of the Department.

According to an eighteenth aspect of the present invention, the bicycle sprocket assembly according to the seventeenth aspect is configured such that the intermediate portion includes a first attachment hole securing the second sprocket to the first chain A fastener of the wheel passes through the hole, and the first circumferential wall on the protrusion is positioned radially outward from the first attachment hole.

According to a nineteenth aspect of the present invention, the bicycle sprocket assembly according to the eighteenth aspect is configured such that the second sprocket body includes a second attachment hole through which the fastener passes, and the The second circumferential wall in the recess is positioned radially outward from the second attachment hole.

With the bicycle sprocket assembly according to any one of the sixteenth to nineteenth aspects, the first circumferential wall and the first radial wall can be formed by a single protrusion, and thus the formation of the a circumferential wall and the first radial wall.

According to a twentieth aspect of the present invention, according to any one of the first aspect to the eighth aspect, the eleventh aspect to the thirteenth aspect, and the sixteenth aspect to the seventeenth aspect the bicycle sprocket assembly is configured such that the intermediate portion defines a first attachment surface, a first attachment hole is formed on the first attachment surface, the second sprocket body defines a second attachment surface, A second attachment hole is formed on the second attachment surface, and the fastener passes through the first attachment hole and the second attachment hole to attach the second sprocket to the first sprocket.

With the bicycle sprocket assembly according to the twentieth aspect, the second sprocket can be tightly secured to the first sprocket.

According to a twenty-first aspect of the present invention, the bicycle sprocket assembly according to the twentieth aspect is configured such that the first attachment surface is configured to be parallel to the central axis of rotation in the assembled state One of the axial directions directly contacts the second attachment surface.

With the bicycle sprocket assembly according to the twenty-first aspect, the second sprocket can be positioned relative to the first sprocket in the axial direction.

According to a twenty-second aspect of the present invention, the bicycle sprocket assembly according to the twenty-first aspect is configured such that one of the first attachment hole and the second attachment hole is a through hole and the The other of the first attachment hole and the second attachment hole is a threaded hole, and the fastener is screwed into the threaded hole through the through hole to fix the second sprocket to the first sprocket, And in the assembled state, a gap is formed between the fastener and the through hole in at least one circumferential direction.

According to a twenty-third aspect of the present invention, the bicycle sprocket assembly according to any one of the first to twenty-second aspects is configured such that the total number of the first teeth is greater than the total number of the second teeth total.

According to a twenty-fourth aspect of the present invention, the bicycle sprocket assembly according to any one of the first to twenty-third aspects is configured such that the central portion includes at least a connection with the crank arm and the crank axle One engages a plurality of bolt grooves.

With the bicycle sprocket assembly according to any one of the twenty-second aspect to the twenty-fourth aspect, the fastener securing the second sprocket to the first sprocket can be prevented from loosening because the tightening The fasteners are not used to relatively position the first sprocket and the second sprocket in at least one of the circumferential direction and the radial direction with respect to the central axis of rotation.

Selected embodiments of the present invention will now be explained with reference to the drawings. Those skilled in the art will understand from the present disclosure that the following descriptions of embodiments of the present invention are provided for illustration only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents. first embodiment

Referring first to Figures 1A and 1B, a bicycle sprocket assembly 10 is a direct mount bicycle sprocket assembly. The bicycle sprocket assembly 10 having a rotation center axis CA includes a first sprocket 12 and a second sprocket 14 . The first sprocket 12 includes first teeth 16 , a first sprocket body 18 and at least one first engaging portion 20 . The first sprocket body 18 includes a central portion 22, a radially outer portion 24, and the central portion 22 and the radially outer portion 24 disposed in a radial direction relative to the central axis of rotation CA of the bicycle sprocket assembly 10 At least one intermediate portion 26 therebetween. The first teeth 16 are formed along a radially outer periphery of the radially outer portion 24 . The central portion 22 has a torque transfer profile 28 that engages with at least one of a crank arm CR and a crankshaft (not shown) to transfer a pedaling torque from the crank arm CR to the first tooth 16 . In this embodiment, the torque transmission profile 28 of the central portion 22 engages with the crank arm CR. The first engaging portion 20 is disposed on the first sprocket body 18 . The second sprocket 14 includes second teeth 30 , a second sprocket body 32 and at least one second engaging portion 34 . The second sprocket body 32 is formed with second teeth 30 along a radially outer periphery of the second sprocket body 32 . The second engaging portion 34 is disposed on the second sprocket body 32 and engages with the first engaging portion 20 in an assembled state ( FIG. 1A ) in which the second sprocket 14 is attached to the first sprocket 12 to The bicycle sprocket assembly 10 positions the second sprocket 14 relative to the first sprocket 12 in at least one of a circumferential direction and the radial direction relative to the central axis of rotation CA. In addition, a lock ring LR is used to engage with the crank arm CR to clamp the bicycle sprocket assembly 10 between the lock ring LR and the crank arm CR in an axial direction parallel to the rotation center axis CA. With the engagement between the second engaging portion 34 and the first engaging portion 20, a fastener 52, such as a screw, is used to secure the second sprocket 14 to the first sprocket 12 in the axial direction only, without using The first sprocket 12 and the second sprocket 14 are relatively positioned in at least one of the circumferential direction and the radial direction with respect to the rotation center axis CA. Thus, the fasteners 52 will not carry the reciprocating pedal torque and thus will not become loose due to the reciprocating pedal torque after prolonged use.

In this embodiment, for example, there are four intermediate portions 26, four first meshing portions 20 in the first sprocket 12, and four second meshing portions 34 in the second sprocket 14, but not in equal numbers limited to this. In the following description of the details of the bicycle sprocket assembly 10, only one of the intermediate portions 26, one of the first engaging portions 20, and one of the second engaging portions 34 are described for the sake of brevity, since the other intermediate portions The portion, the first engaging portion and the second engaging portion have a substantially identical configuration.

The first engaging portion 20 is formed on the intermediate portion 26 . As shown in FIGS. 1C and ID, the first engagement portion 20 includes at least one first radial wall 36 extending in the radial direction and the second engagement portion 34 includes at least a second diameter extending in the radial direction towards wall 38. As shown in FIGS. 1E and 1F , the first radial wall 36 and the second radial wall 38 are circumferentially facing each other in the assembled state to transmit pedaling torque in the circumferential direction. The first radial wall 36 is formed on a circumferential edge of the intermediate portion 26 in the circumferential direction. The second engagement portion 34 includes a recess 40 in which the second radial wall 38 is formed. The recess 40 receives a portion of the intermediate portion 26 . Preferably, the inside edge of the recess 40 is formed with a slope SP as shown in Figure ID for preventing sharp edges. In one particular embodiment, the recess 40 may be 0.8±0.1 mm deep, and the thickness of the second sprocket body 32 of the second sprocket 14 is less than 5.1 mm.

As shown in Figure 1C, the first engagement portion 20 includes a first circumferential wall 42 extending in the circumferential direction. As shown in Figure ID, the second engagement portion 34 includes a second circumferential wall 44 extending in the circumferential direction. As shown in FIGS. 1E and 1G , the first circumferential wall 42 and the second circumferential wall 44 face each other in the radial direction in the assembled state.

In this embodiment, the first engagement portions 20 each include a first circumferential rib 46 extending in the circumferential direction, and a first circumferential wall 42 is formed on the rib, as shown in FIGS. 1C and 1G . The second sprocket body 32 includes a cutout 48 on which the second circumferential wall 44 is disposed, as shown in FIG. 1D . The truncated portion 48 receives the first circumferential rib 46 in the assembled state, as shown in FIG. 1G . Preferably, a gap CL exists between the cut-out portion 48 and the first circumferential rib 46 . In one particular embodiment, the first circumferential rib 46 may protrude from the intermediate portion 26 by up to 0.8±0.1 mm, and the truncated portion 48 is 1.1±0.1 deep.

Please refer to Figure 1B. The intermediate portion 26 includes at least one first attachment hole 50 through which at least one fastener 52 that secures the second sprocket 14 to the first sprocket 12 passes. In this embodiment, the first circumferential rib 46 is disposed radially inward away from the first attachment hole 50, as shown in Figure 1C. The second sprocket body 32 includes at least one second attachment hole 54 through which the fastener 52 passes and the cutout 48 is positioned radially inward from the second attachment hole 54, as shown in Figure ID.

Please refer to FIGS. 1B to 1D . The intermediate portion 26 defines a first attachment surface 56 in which the first attachment holes 50 are formed. The second sprocket body 32 defines a second attachment surface 58 in which the second attachment holes 54 are formed. Fasteners 52 pass through first attachment holes 50 and second attachment holes 54 to attach second sprocket 14 to first sprocket 12 . The first attachment surface 56 is configured to directly contact the second attachment surface 58 in an assembled state in an axial direction parallel to the central axis of rotation CA.

One of the first attachment hole 50 and the second attachment hole 54 is a through hole and the other of the first attachment hole 50 and the second attachment hole 54 is a threaded hole. Fasteners 52 are threaded into threaded holes via through holes to secure second sprocket 14 to first sprocket 12 and a gap GP as shown in FIGS. 1F and 1G is at least in the circumferential direction in the assembled state Formed between the fastener 52 and the through hole. In this embodiment, the first attachment hole 50 is a threaded hole and the second attachment hole 54 is a through hole. Fasteners 52 are threaded into first attachment holes 50 via second attachment holes 54 to secure second sprocket 14 to first sprocket 12 . A gap GP as shown in FIGS. 1F and 1G is formed between the fastener 52 and the second attachment hole 54 in both the circumferential direction and the radial direction in the assembled state to prevent use in the circumferential direction and the radial direction The fasteners 52 securing the second sprocket 14 to the first sprocket 12 are loosened in both directions.

Please refer to FIGS. 1A and 1B again. Typically and preferably, the total number of first teeth 16 is greater than the total number of second teeth 30 . That is, the first sprocket 12 having the central portion 22 having the torque transfer profile 28 meshing with at least one of a crank arm CR and a crank shaft (not shown) is a larger sprocket and the second sprocket 14 is One smaller sprocket. Preferably, the central portion 22 includes a plurality of key grooves for the torque transmission profile 28 to engage with at least one of a crank arm CR and a crank shaft (not shown). More specifically, in the illustrated embodiment, the crank arm CR includes a mounting protrusion CRM formed around a mounting hole CRH through which the crank shaft passes. The mounting protrusion CRM protrudes from one end of the crank arm CR in the axial direction. The mounting protrusion includes a plurality of key grooves CRS around the periphery of the mounting protrusion CRM to engage with the plurality of key grooves CRS of the torque transfer profile 28 .

Please refer to Figure 1A. The first sprocket 12 further includes a first sprocket body 18 for assisting in shifting a chain CH from the smaller second sprocket 14 to one of the larger first sprocket 12 as shown in FIGS. 1I and 1J . The plurality of shift assist protrusions 60 are operated. A shift area SA is defined on the first sprocket 12 adjacent to each of the shift assist protrusions 60 . For details of one of the shift areas SA, please refer to FIG. 1H . The shift area SA shown in FIG. 1H includes a plurality of shift teeth (eg, four shift teeth in this example) of the first tooth 16 , which etc. can be found in the chain CH from the smaller second sprocket 14 to the larger The large first sprocket 12 contacts the chain CH during the shifting operation. The first teeth 16 include a first chain receiving tooth 62 and a second chain receiving tooth 64 in an upstream direction UD with respect to a chain running direction near the end of the shifting area SA. The first chain receiving teeth 62 and the second chain receiving teeth 64 are engaged with the first and second teeth of the chain CH during the shifting operation. The first chain receiving teeth 62 and the second chain receiving teeth 64 are respectively formed with a cut-out portion 66 on their tip portions for easy engagement with the chain CH. Specifically, the cutout portion 66 is formed on one edge of the tip portions of the first chain receiving tooth 62 and the second chain receiving tooth 64 in a downstream direction DD with respect to the running direction of the chain. Due to the cutout 66, a tooth top 68 of each of the first chain receiving tooth 62 and the second chain receiving tooth 64 is relative to the first chain receiving tooth 62 and the second chain in the upstream direction UD of the chain running direction A circumferential centerline CC of each of the receiving teeth 64 is offset.

Please refer to FIG. 1I and FIG. 1J. During a shift operation from the smaller second sprocket 14 to the one of the larger first sprocket 12, the chain CH first engages the shift assist protrusion 60, as shown in FIG. 1I. As shown in FIG. 1J , the first chain receiving teeth 62 easily mesh with the chain CH. By virtue of the cut-out portions 66 of the first chain receiving teeth 62 and the second chain receiving teeth 64, the first chain receiving teeth 62 and the second chain receiving teeth 64 can easily engage with the outer chain plate OP of the chain CH through the entrance EH of the meshing area. meshing area. In the chain CH of this example, the entrance EH of the meshing area between the outer link plates OP is formed smaller than usual because the inner link plate IP of the chain CH is formed wider than usual to hold the teeth of the sprocket more securely . However, the smaller entry EH makes the engagement of the chain CH to the teeth of the sprocket more difficult. The cutouts 66 ensure that the first chain receiving teeth 62 and the second chain receiving teeth 64 smoothly engage the chain CH during shifting operations. Thus, the chain receiving teeth 62, 64 and the chain CH outer link plate OP can be moved when the chain CH is shifted from a smaller sprocket (second sprocket 14) towards a larger sprocket (first sprocket 12). Engage firmly and smoothly.

Please refer to FIG. 1K and FIG. 1L. The crank arm CR of this embodiment is a hollow crank arm and includes an inner portion CRI and an outer housing CRO. The inner portion CRI and an outer housing CRO are assembled and joined together to form the crank arm CR. Preferably, the inner portion of the CRI is formed with a vent hole VH. The bonding between the inner portion CRI and the outer casing CRO is achieved using an adhesive. Although the adhesive is cured at a high temperature, gas is allowed to escape from the interior of the hollow crank arm CR through the vent hole VH. Since some further procedures, such as an anodization procedure, can be applied to the assembled crank arm CR, the vent hole VH should be sealed by a sealer to prevent any unwanted material from entering the crank arm CR. Therefore, the crank arm CR of this embodiment further includes a sealing bolt SB to seal the vent hole VH. The vent hole VH is threaded so that the sealing bolt SB is screwed into the vent hole VH and seals the vent hole VH.

For details of the sealing bolt SB, please refer to Fig. 1M. Preferably, the sealing bolt SB includes a flange SBF, a threaded portion SBT and a recessed portion SBO. The flange SBF is used to cover and seal the vent hole VH. The threaded portion SBT is for screwing into the vent hole VH. An O-ring may be placed in the recess SBO to seal the vent hole VH.

In an alternative embodiment, the second radial wall 38 may be formed at only one side of each of the attachment holes 54 in the circumferential direction. In other words, as shown in FIG. 1N , the second radial wall 38 is not formed at the other side of each of the attachment holes 54 on the second sprocket 14 , and thus the corresponding first radial wall 36 does not contact any The second radial wall 38 . In this alternative embodiment, as shown in FIG. 1N , there are four second radial walls 38 . There is a pair of adjacent attachment holes 54 between a pair of adjacent second radial walls 38 in the circumferential direction. There is no second radial wall 38 between the other pair of adjacent attachment holes 54 in the circumferential direction. By the adjacent two second radial walls 38, the first sprocket 12 and the second sprocket 14 can be positioned in the circumferential direction.

Although the alternative embodiments described above are in relation to the second radial wall, it is also possible to form the first radial wall or the first and second radial walls on only one side of the attachment hole in the circumferential direction.

In another alternative embodiment, the second radial wall 38 may be formed adjacent to only both of the attachment holes. As shown in FIG. 10 , each of a first pair of attachment holes 54 is circumferentially disposed between a pair of adjacent second radial walls 38 to circumferentially position the first sprocket 12 and the second chain round 14. The second radial wall 38 is not formed adjacent to a second pair of attachment holes 54'. In other words, in one aspect, the second radial walls 38 are formed circumferentially adjacent both sides of the first pair of attachment holes 54 . On the other hand, no second radial wall is formed in the circumferential direction near either side of the second pair of attachment holes 54'. The first pair of attachment holes 54 are disposed opposite to each other with respect to the rotation center axis CA. The other two attachment holes 54' (ie, the second pair of attachment holes 54') are also positioned opposite to each other with respect to the rotation center axis CA. The attachment holes 54 and 54' are alternately and adjacently disposed in the circumferential direction. The diameter of the second pair of attachment holes 54' (through holes) is larger than the diameter of the first pair of attachment holes 54 (through holes) to prevent abutment of the fastener 52 with the attachment holes 54'. Thus, this ensures the positioning of the first sprocket 12 and the second sprocket 14 in the circumferential direction by the first radial wall 36 and the second radial wall 38 rather than by the fasteners 52 .

Although the alternative embodiments described above are with respect to the second radial wall, it is also possible to form the first radial wall or the first and second radial walls circumferentially adjacent to only both of the attachment holes. Second Embodiment

For a second embodiment of a bicycle sprocket assembly 210 , please refer to FIGS. 2A and 2B . Similar to the first embodiment, the bicycle sprocket assembly 210 includes a first sprocket 212 and a second sprocket 214 . The first sprocket 212 includes first teeth 216 , a first sprocket body 218 and at least one first engaging portion 220 . The first sprocket body 218 includes a central portion 222, a radially outer portion 224, and the central portion 222 and the radially outer portion 224 are disposed in a radial direction relative to the central axis of rotation CA of the bicycle sprocket assembly 210 At least one intermediate portion 226 therebetween. The first teeth 216 are formed along a radially outer periphery of the radially outer portion 224 . The central portion 222 has a torque transfer profile 228 that meshes with at least one of a crank arm CR as shown in FIG. 1B and a crankshaft (not shown) to transfer a pedaling torque from the crank arm CR to the first tooth 216 . In this embodiment, the torque transfer profile 228 of the central portion 222 is used to engage the crank arm CR, as shown in Figure IB. The first engagement portion 220 is disposed on the first sprocket body 218 . The second sprocket 214 includes second teeth 230 , a second sprocket body 232 and at least one second engaging portion 234 . The second sprocket body 232 is formed with second teeth 230 along a radially outer periphery of the second sprocket body 232 . The second engaging portion 234 is disposed on the second sprocket body 232 and engages with the first engaging portion 220 in an assembled state ( FIG. 2A ) in which the second sprocket 214 is attached to the first sprocket 212 to be in The bicycle sprocket assembly 210 positions the second sprocket 214 relative to the first sprocket 212 in at least one of a circumferential direction and the radial direction relative to the central axis of rotation CA.

The first engaging portion 220 is formed on the intermediate portion 226 . As shown in Figures 2C and 2D, the first engagement portion 220 includes at least one first radial wall 236 extending in the radial direction and the second engagement portion 234 includes at least a second diameter extending in the radial direction towards wall 238. As shown in Figures 2E and 2F, the first radial wall 236 and the second radial wall 238 circumferentially face each other in the assembled state to transmit pedaling torque circumferentially. In this embodiment, the first radial wall 236 is formed on a circumferential edge of the intermediate portion 226 in the circumferential direction. The second engagement portion 234 includes a recess 240 in which the second radial wall 238 is formed, and the recess 240 receives a portion of the intermediate portion 226 . Preferably, the inside edge of the recess 240 is formed as a rounded edge RE as shown in FIG. 2D for preventing sharp edges. In one particular embodiment, the recess 240 may be 0.8±0.1 mm deep, and the thickness of the second sprocket body 232 of the second sprocket 214 is less than 5.1 mm.

As shown in Figure 2C, the first engagement portion 220 includes a first circumferential wall 242 extending in the circumferential direction. As shown in Figure 2D, the second engagement portion 234 includes a second circumferential wall 244 extending in the circumferential direction. As shown in Figure 2G, the first circumferential wall 242 and the second circumferential wall 244 face each other in the radial direction in the assembled state.

Other details and alternatives to the elements of the bicycle sprocket assembly 210 are similar to those of the bicycle sprocket assembly 10 of the first embodiment and are therefore not described below. The following describes a portion of the bicycle sprocket assembly 210 that is different from the portion of the bicycle sprocket assembly 10 of the first embodiment.

As shown in FIG. 2D, the second engagement portion 234 in the second embodiment includes a second circumferential rib 246 on which a second circumferential wall 244 is formed. Accordingly, the first engagement portion 220 includes a recessed portion 248 on which the first circumferential wall 242 is formed, as shown in FIG. 2C. The recessed portion 248 receives the second circumferential rib 246 in the assembled state, as shown in Figure 2G. Preferably, the outer edge of the first circumferential wall 242 is formed with a chamfer CF, as shown in Figure 2G. In a specific embodiment, the thickness of the second circumferential rib 246 may be 0.8±0.1 mm.

Please refer to Figure 2C. Preferably, the recessed portion 248 is disposed between the intermediate portion 226 and the radially outer portion 224 in the radial direction. The first sprocket body 218 includes at least one bridge portion 249 disposed adjacent to the recessed portion 248 in the circumferential direction. The bridge portion 249 smoothly connects the first circumferential wall 242 to the radially outer portion 224 . Please refer to FIGS. 2B to 2F . The middle portion 226 includes a first attachment hole 250 through which a fastener 252 that secures the second sprocket 214 to the first sprocket 212 passes. In this embodiment, the recessed portion 248 is positioned radially outward from the first attachment hole 250 . Accordingly, the second sprocket body 232 includes a second attachment hole 254 through which the fastener 252 passes. A second circumferential rib 246 for engaging the recessed portion 248 is positioned radially outward from the second attachment hole 254 . Third Embodiment

For a third embodiment of a bicycle sprocket assembly 310 , please refer to FIGS. 3A and 3B . Similar to the first embodiment, the bicycle sprocket assembly 310 includes a first sprocket 312 and a second sprocket 314 . The first sprocket 312 includes first teeth 316 , a first sprocket body 318 and at least one first engaging portion 320 . The first sprocket body 318 includes a central portion 322, a radially outer portion 324, and the central portion 322 and the radially outer portion 324 are disposed in a radial direction relative to the central axis of rotation CA of the bicycle sprocket assembly 310 At least one intermediate portion 326 therebetween. The first teeth 316 are formed along a radially outer periphery of the radially outer portion 324 . The central portion 322 has a torque transfer profile 328 that meshes with at least one of a crank arm CR as shown in FIG. 1B and a crankshaft (not shown) to transfer a pedaling torque from the crank arm CR to the first tooth 316 . In this embodiment, the torque transfer profile 328 of the central portion 322 is used to engage the crank arm CR. The first engaging portion 320 is disposed on the first sprocket body 318 . The second sprocket 314 includes second teeth 330 , a second sprocket body 332 and at least one second engaging portion 334 . The second sprocket body 332 is formed with second teeth 330 along a radially outer periphery of the second sprocket body 332 . The second engaging portion 334 is disposed on the second sprocket body 332 and engages with the first engaging portion 320 in an assembled state ( FIG. 3A ) in which the second sprocket 314 is attached to the first sprocket 312 to be in The bicycle sprocket assembly 310 positions the second sprocket 314 relative to the first sprocket 312 in at least one of a circumferential direction and the radial direction relative to the central axis of rotation CA.

The first engaging portion 320 is formed on the intermediate portion 326 . As shown in Figures 3C and 3D, the first engagement portion 320 includes at least one first radial wall 336 extending in the radial direction and the second engagement portion 334 includes at least a second diameter extending in the radial direction towards wall 338. As shown in Figures 3E and 3F, the first radial wall 336 and the second radial wall 338 circumferentially face each other in the assembled state to transmit pedaling torque circumferentially. The first radial wall 336 is formed on a circumferential edge of the intermediate portion 326 in the circumferential direction. The second engagement portion 334 includes a recess 340 in which the second radial wall 338 is formed, and the recess 340 receives a portion of the intermediate portion 326 . Preferably, the inside edge of the recess 340 is formed as a rounded edge RE as shown in FIG. 3D for preventing sharp edges. In one particular embodiment, the recess 340 may be 0.8±0.1 mm deep, and the thickness of the second sprocket body 332 of the second sprocket 314 is less than 5.1 mm.

As shown in Figure 3C, the first engagement portion 320 includes a first circumferential wall 342 extending in the circumferential direction. As shown in Figure 3D, the second engagement portion 334 includes a second circumferential wall 344 extending in the circumferential direction. As shown in Figure 3G, the first circumferential wall 342 and the second circumferential wall 344 face each other in the radial direction in the assembled state.

Other details and alternatives to the elements of the bicycle sprocket assembly 310 are similar to those of the bicycle sprocket assembly 10 of the first embodiment and are therefore not described below. The following describes the portion of the bicycle sprocket assembly 310 that is different from the portion of the bicycle sprocket assembly 10 of the first embodiment.

As shown in FIG. 3C , the first engagement portion 320 of this embodiment includes a protrusion 346 protruding from the middle portion 326 . The protrusions 346 define the first circumferential wall 342 and the first radial wall 336 . Therefore, in this embodiment, the second circumferential wall 344 is formed in the recess 340 contained by the second engaging portion 334 . The recess 340 receives at least a portion of the protrusion 346 in the assembled state, as shown in Figure 3G. Preferably, the outer edge of the first circumferential wall 342 on the protrusion 346 is formed with a chamfer CF, as shown in Figure 3G.

Please refer to FIGS. 3B to 3F . The middle portion 326 includes a first attachment hole 350 through which a fastener 352 that secures the second sprocket 314 to the first sprocket 312 passes. In this embodiment, the first circumferential wall 342 on the protrusion 346 is disposed radially outward from the first attachment hole 350 . Thus, the second sprocket body 314 includes a second attachment hole 354 through which the fastener 352 passes, and the second circumferential wall 344 in the recess is disposed radially outward from the second attachment hole 354 .

Those skilled in the bicycle art will appreciate from this disclosure that the above-described embodiments may be at least partially combined with each other as needed or desired.

In this application, the term "comprising" and its derivatives as used herein are intended to be open-ended terms that specify the presence of a stated feature, element, component, group, integer and/or step, but The presence of other unrecited features, elements, components, groups, integers and/or steps is not excluded. This concept also applies to words of similar meaning, eg, the terms "has", "includes" and their derivatives.

The terms "component", "section", "section", "part", "element", "body" and "structure" when used in the singular can have the dual meaning of a single part or a plurality of parts.

Ordinal numbers such as "first" and "second" as stated in this application are merely identifiers and do not have any other meaning (eg, a particular order or the like). Also, for example, the term "first element" does not by itself imply the presence of a "second element," and the term "second element" does not by itself imply the presence of a "first element."

The term "pair," as used herein, may also encompass configurations in which the pair of elements have different shapes or structures than each other, in addition to configurations in which the pair of elements have the same shape or structure as each other.

The terms "a," "one or more," and "at least one" are used interchangeably herein.

Finally, terms of degree (such as "substantially," "approximately," and "approximately" as used herein) mean a reasonable amount of deviation from the modified term such that the end result is not significantly changed. All numerical values described in this application may be deemed to include terms such as "substantially," "approximately," and "approximately."

Obviously, many modifications and variations of the present invention are possible in light of the above teachings. Therefore, it is to be understood that within the scope of the appended claims, the present invention may be practiced otherwise than as specifically described herein.

10‧‧‧Bicycle sprocket assembly 12‧‧‧First sprocket 14‧‧‧Second sprocket 16‧‧‧First tooth 18‧‧‧First sprocket body 20‧‧‧Meshing part 22‧‧ ‧Central part 24‧‧‧Radially outer part 26‧‧‧Middle part 28‧‧‧Torque transmission profile 30‧‧‧Second tooth 32‧‧‧Second sprocket body 34‧‧‧Second engaging part 36‧ ‧‧First Radial Wall 38‧‧‧Second Radial Wall 40‧‧‧Recess 42‧‧‧First Circumferential Wall 44‧‧‧Second Circumferential Wall 46‧‧‧First Circumferential Rib 48‧‧‧ Cutout 50‧‧‧First Attachment Hole 52‧‧‧ Fastener 54‧‧‧Second Attachment Hole 54'‧‧‧ Attachment Hole 56‧‧‧First Attachment Surface 58‧‧‧Second Attachment surface 60‧‧‧Shift assist protrusion 62‧‧‧First chain receiving tooth 64‧‧‧Second chain receiving tooth 66‧‧‧Cut 68‧‧‧Top 210‧‧‧Bicycle sprocket Assembly 212‧‧‧First sprocket 214‧‧‧Second sprocket 216‧‧‧First tooth 218‧‧‧First sprocket body 220‧‧‧First engaging part 222‧‧‧Center part 224‧ ‧‧Radial outer part 226‧‧‧Middle part 228‧‧‧Torque transmission profile 230‧‧‧Second tooth 232‧‧‧Second sprocket body 234‧‧‧Second engaging part 236‧‧‧First diameter Toward Wall 238‧‧‧Second Radial Wall 240‧‧‧Recess 242‧‧‧First Circumferential Wall 244‧‧‧Second Circumferential Wall 246‧‧‧Second Circumferential Rib 248‧‧‧Recess 249‧ ‧‧Bridge portion 250‧‧‧First attachment hole 252‧‧‧ Fastener 254‧‧‧Second attachment hole 310‧‧‧Bicycle sprocket assembly 312‧‧‧First sprocket 314‧‧‧Part Second sprocket 316‧‧‧First tooth 318‧‧‧First sprocket body 320‧‧‧First engaging part 322‧‧‧Central part 324‧‧‧Radially outer part 326‧‧‧Middle part 328‧‧ ‧Torque transmission profile 330‧‧‧Second tooth 332‧‧‧Second sprocket body 334‧‧‧Second engaging portion 336‧‧‧First radial wall 338‧‧‧Second radial wall 340‧‧‧ Recess 342‧‧‧First Circumferential Wall 344‧‧‧Second Circumferential Wall 346‧‧‧Protrusion 350‧‧‧First Attachment Hole 352‧‧‧ Fastener 354‧‧‧Second Attachment Hole CA‧‧ ‧Central Rotation Shaft CF‧‧‧Chamfer CH‧‧‧Chain CL‧‧‧Clearance CR‧‧‧Crank arm CRH‧‧‧Mounting hole CRI‧‧‧Inner part CRM‧‧‧Mounting protrusion CRO‧‧‧Case Body CRS‧‧‧Bolt Groove DD‧‧‧Downstream EH‧‧‧Inlet GP‧‧‧Clearance IP‧‧‧Inner Link Plate LR‧‧‧Lock Ring OP‧‧‧Outer Link Plate RE‧‧‧Round Edge SA‧‧‧Shift area SB‧‧‧Sealing bolt SBF‧‧‧Flange SBO‧‧‧Concave part SBT‧‧‧Threaded part SP‧‧‧Slope UD‧‧‧Upstream direction VH‧‧‧Pass gas

A more complete understanding of the present invention and one of its many attendant advantages will be better understood and readily obtained by reference to the following embodiments when considered in conjunction with the accompanying drawings.

1A is a perspective view of a bicycle sprocket assembly according to a first embodiment of the present invention.

1B is an exploded view of the bicycle sprocket assembly according to the first embodiment of the present invention.

1C is a partial enlarged view of the first sprocket according to the first embodiment of the present invention.

1D is a partial enlarged view of the second sprocket according to the first embodiment of the present invention.

1E is a partial enlarged view of the first sprocket and the second sprocket in an assembled state according to the first embodiment of the present invention.

Figure 1F is a partial cross-sectional view of a bicycle sprocket assembly taken along line 1F-1F of Figure 1A.

Figure 1G is a partial cross-sectional view of a bicycle sprocket assembly taken along line 1G-1G of Figure 1A.

1H is an enlarged partial view of a bicycle sprocket assembly according to a first embodiment of the present invention showing details of one of the shifting areas.

1I is an enlarged partial view showing a shift assist protrusion of a bicycle sprocket assembly according to a first embodiment of the present invention entering into a chain during a shift operation.

1J is a partially enlarged view showing an engagement between the chain of the bicycle sprocket assembly according to the first embodiment of the present invention and the shift assist protrusion during a shifting operation.

1K shows a crank arm for use with a bicycle sprocket assembly according to the first embodiment of the present invention with a sealing bolt inserted into a vent hole.

1L shows a crank arm for use with a bicycle sprocket assembly according to the first embodiment of the present invention, with the sealing bolt separated from the vent hole.

Figure 1M shows a side view of the sealing bolt shown in Figures 1K and 1L.

Figure 1N shows an alternative embodiment of the first embodiment of the present invention in which the second radial wall is formed at only one side of each of the attachment holes in the circumferential direction.

Figure 10 shows another alternative to the first embodiment of the present invention in which the second radial wall is adjacent only to both of the attachment holes.

2A is a perspective view of a bicycle sprocket assembly according to a second embodiment of the present invention.

2B is an exploded view of a bicycle sprocket assembly according to a second embodiment of the present invention.

2C is a partial enlarged view of the first sprocket according to the second embodiment of the present invention.

2D is a partial enlarged view of the second sprocket according to the second embodiment of the present invention.

2E is a partial enlarged view of the first sprocket and the second sprocket in an assembled state according to the second embodiment of the present invention.

Figure 2F is a partial cross-sectional view of the bicycle sprocket assembly taken along line 2F-2F of Figure 2A.

Figure 2G is a partial cross-sectional view of the bicycle sprocket assembly taken along line 2G-2G of Figure 2A.

3A is a perspective view of a bicycle sprocket assembly according to a third embodiment of the present invention.

3B is an exploded view of a bicycle sprocket assembly according to a third embodiment of the present invention.

3C is a partial enlarged view of the first sprocket according to the third embodiment of the present invention.

3D is a partial enlarged view of the second sprocket according to the third embodiment of the present invention.

3E is a partial enlarged view of the first sprocket and the second sprocket in an assembled state according to the third embodiment of the present invention.

Figure 3F is a partial cross-sectional view of the bicycle sprocket assembly taken along line 3F-3F of Figure 3A.

Figure 3G is a partial cross-sectional view of a bicycle sprocket assembly taken along line 3G-3G of Figure 3A.

10‧‧‧Bicycle sprocket assembly

12‧‧‧First sprocket

14‧‧‧Second sprocket

16‧‧‧First tooth

18‧‧‧First sprocket body

30‧‧‧Second tooth

52‧‧‧ Fasteners

60‧‧‧Shift assist protrusion

CA‧‧‧Central axis of rotation

CR‧‧‧Crank Arm

LR‧‧‧Lock ring

SA‧‧‧Shift area

Claims (18)

A bicycle sprocket assembly with a central axis of rotation, the bicycle sprocket assembly includes: a first sprocket, which includes: first teeth, a first sprocket body, which includes a central portion, a radial outer portion and an intermediate portion disposed between the central portion and the radially outer portion in a radial direction relative to the central axis of rotation of the bicycle sprocket assembly, the first teeth along the diameter formed at a radially outer periphery of the outward portion, the central portion having a torque transfer profile that engages with at least one of a crank arm and a crank shaft to transfer a pedaling torque from the crank arm to the first teeth, and a first engaging portion disposed on the first sprocket body; and a second sprocket including: second teeth, a second sprocket body having a length along the second sprocket body The second teeth are formed on a radially outer periphery, a second engaging portion disposed on the second sprocket body and in an assembled state in which the second sprocket is attached to the first sprocket engaging with the first engaging portion to position the second sprocket relative to the first sprocket in at least one of a circumferential direction and the radial direction of the bicycle sprocket assembly relative to the central axis of rotation; wherein the first engaging portion includes a first circumferential wall extending in the circumferential direction and the second engaging portion includes a second circumferential wall extending in the circumferential direction, and the first and second circumferential walls are facing each other in the radial direction in the assembled state, and Wherein the first engaging portion includes a first circumferential rib extending in the circumferential direction and the first circumferential wall is formed on the first circumferential rib, preferably, the second sprocket body includes a section a cut-out portion on which the second circumferential wall is disposed, and the cut-out portion receives the first circumferential rib portion in the assembled state. The bicycle sprocket assembly of claim 1, wherein the first engaging portion is formed on the intermediate portion. The bicycle sprocket assembly of claim 1 or 2, wherein the first engagement portion includes a first radial wall extending in the radial direction and the second engagement portion includes a first radial wall extending in the radial direction A second radial wall, and the first radial wall and the second radial wall face each other in the circumferential direction in the assembled state, preferably the first radial wall is formed in the circumferential direction at on one of the circumferential edges of the intermediate portion. The bicycle sprocket assembly of claim 3, wherein the second engagement portion includes a recess in which the second radial wall is formed, and the recess receives a portion of the intermediate portion. The bicycle sprocket assembly of claim 1, wherein the intermediate portion includes a first attachment hole through which a fastener for securing the second sprocket to the first sprocket passes, and the A first circumferential rib is positioned radially inward from the first attachment hole. The bicycle sprocket assembly of claim 5, wherein the second sprocket body includes a second attachment hole through which the fastener passes, and the cutout portion is positioned away from the second attachment Contact hole the radial interior. The bicycle sprocket assembly of claim 1, wherein the second engaging portion includes a second circumferential rib, the second circumferential wall is formed on the second circumferential rib, preferably, the first engaging portion includes a second circumferential rib. A recessed portion on which the first circumferential wall is formed and which receives the second circumferential rib in the assembled state. The bicycle sprocket assembly of claim 7, wherein the recessed portion is disposed in the radial direction between the intermediate portion and the radially outer portion, and the first sprocket body includes disposed in the circumferential direction a bridge portion adjacent to the recessed portion. The bicycle sprocket assembly of claim 7, wherein the intermediate portion includes a first attachment hole through which a fastener that secures the second sprocket to the first sprocket passes, and the A recessed portion is positioned radially outward from the first attachment hole. The bicycle sprocket assembly of claim 9, wherein the second sprocket body includes a second attachment hole through which the fastener passes, and the second circumferential rib is positioned away from the first Two are attached to the radially outer portion of the hole. The bicycle sprocket assembly of claim 1, wherein the first engaging portion comprises a protrusion from the intermediate portion, and the protrusion defines the first circumferential wall and the first radial wall, preferably the The second engaging portion includes a recess in which the second circumferential wall is formed, and the recess receives at least a portion of the protrusion. The bicycle sprocket assembly of claim 11, wherein the intermediate portion includes a first attachment hole through which a fastener for securing the second sprocket to the first sprocket passes, and the The first circumferential wall on the protrusion is disposed radially outward from the first attachment hole. The bicycle sprocket assembly of claim 12, wherein the second sprocket body includes a second attachment hole through which the fastener passes, and the second circumferential wall in the recess is disposed in the away from the radially outer portion of the second attachment hole. The bicycle sprocket assembly of claim 1 or 2, wherein the intermediate portion defines a first attachment surface, a first attachment hole is formed on the first attachment surface, and the second sprocket body defines a first attachment surface Two attachment surfaces, a second attachment hole is formed on the second attachment surface, and a fastener passes through the first attachment hole and the second attachment hole to attach the second sprocket to the first sprocket. The bicycle sprocket assembly of claim 14, wherein the first attachment surface is configured to directly contact the second attachment surface in an axial direction parallel to the central axis of rotation in the assembled state. The bicycle sprocket assembly of claim 15, wherein one of the first attachment hole and the second attachment hole is a through hole and the other of the first attachment hole and the second attachment hole is a a threaded hole into which the fastener is screwed via the through hole to fix the second sprocket to the first sprocket, and in the assembled state, the fastener is at least in the circumferential direction A gap is formed with the through hole. The bicycle sprocket assembly of claim 1 or 2, wherein the total number of the first teeth is greater than the total number of the second teeth. The bicycle sprocket assembly of claim 1 or 2, wherein the central portion includes a plurality of peg grooves that engage with the at least one of the crank arm and the crank axle.

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