bicycle chain

Abstract

The objective of this invention is to improve shifting performance. This invention provides a bicycle chain with excellent shifting performance. The bicycle chain of this invention includes a first inner chain plate, a second inner chain plate, a first outer chain plate, a second outer chain plate, a bushing, and a pin. The second inner chain surface at the end of the first inner chain is offset towards the axial center plane of the bicycle chain, at least a portion of which is offset relative to the middle portion of the second inner chain surface towards the axial center plane of the bicycle chain, such that a first axial gap is formed between the second inner chain surface at the end of the first inner chain and the first outer chain surface at the end of the first outer chain, on at least one of the axial directions of the first inner chain and the first outer chain.

Description

Technical Field

[0001] The present invention relates to a chain for a bicycle. Prior Art

[0002] A technology related to a chain for a bicycle is disclosed in Patent Document 1. A pair of inner link plates of the chain are combined by bushings. A pin for connecting a pair of outer link plates is inserted through the bushings. [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Specification of U.S. Patent No. 4,642,078 Summary of the Invention

[0004] [Problems to be Solved by the Invention]

[0005] However, there is still room for improvement in the shifting performance of conventional bicycle chains. The present invention provides a bicycle chain with excellent shifting performance. [Technical Means for Solving the Problems]

[0006] A bicycle chain according to a first aspect of the present invention includes a first inner link plate, a second inner link plate, a first outer link plate, a second outer link plate, a bush, and a pin. The first inner link plate includes: a first inner link end portion including a first inner link opening having a first inner link central axis; a second inner link end portion including a second inner link opening having a second inner link central axis extending parallel to the first inner link central axis; a first inner link intermediate portion connecting the first inner link end portion and the second inner link end portion; a first inner link surface; and a second inner link surface disposed on the opposite side of the first inner link surface in a first inner link axial direction related to the first inner link central axis. The second inner link plate includes: a third inner link end portion including a third inner link opening having a third inner link central axis; a fourth inner link end portion including a fourth inner link opening having a fourth inner link central axis extending parallel to the third inner link central axis; a second inner link intermediate portion connecting the third inner link end portion and the fourth inner link end portion; a third inner link surface configured to face the first inner link surface of the first inner link plate in the first inner link axial direction in an assembled state of the bicycle chain; and a fourth inner link surface disposed on the opposite side of the third inner link surface in a second inner link axial direction related to the third inner link central axis. The first outer link plate is configured to be adjacent to the first inner link plate without interposing other inner link plates or other outer link plates in an assembled state of the bicycle chain. The first outer link plate includes: a first outer link end portion including a first outer link opening having a first outer link central axis; a second outer link end portion including a second outer link opening having a second outer link central axis extending parallel to the first outer link central axis; a first outer link intermediate portion connecting the first outer link end portion and the second outer link end portion; a first outer link surface; and a second outer link surface disposed on the opposite side of the first outer link surface in a first outer link axial direction related to the first outer link central axis. The second outer link plate is configured to be adjacent to the second inner link plate without interposing other inner link plates or other outer link plates in an assembled state of the bicycle chain. The second outer link plate includes: a third outer link end portion including a third outer link opening having a third outer link central axis; a fourth outer link end portion including a fourth outer link opening having a fourth outer link central axis extending parallel to the third outer link central axis; a second outer link intermediate portion connecting the third outer link end portion and the fourth outer link end portion; a third outer link surface configured to face the first outer link surface of the first outer link plate in the first outer link axial direction in an assembled state of the bicycle chain; and a fourth outer link surface disposed on the opposite side of the third outer link surface in a second outer link axial direction related to the third outer link central axis.Moreover, the above-mentioned bushing has a bushing opening and is configured to be inserted into the above-mentioned first inner chain opening and the above-mentioned third inner chain opening in the assembled state of the above-mentioned bicycle chain. The above-mentioned pin is configured to be inserted into the above-mentioned first outer chain opening and the above-mentioned third outer chain opening in the assembled state of the above-mentioned bicycle chain, and passes through the above-mentioned bushing opening. The above-mentioned second inner chain surface of the above-mentioned first inner chain end portion is at least on one of the above-mentioned first inner chain axial direction and the above-mentioned first outer chain axial direction, and a first axial gap is formed between the above-mentioned second inner chain surface of the above-mentioned first inner chain end portion and the above-mentioned first outer chain surface of the above-mentioned first outer chain end portion. In this way, relative to the above-mentioned second inner chain surface of the above-mentioned first inner chain middle portion, at least a part is offset toward the axial center plane of the above-mentioned bicycle chain. For the bicycle chain according to the above-mentioned first aspect, the wear resistance is improved by the bushing structure, and, due to the formation of the axial gap, the bicycle chain is easily bent, and the shifting performance is excellent. ;

[0007] In the bicycle chain according to the second aspect that complies with the above-mentioned first aspect, the above-mentioned fourth inner chain surface of the above-mentioned third inner chain end portion is at least on one of the above-mentioned second inner chain axial direction and the above-mentioned second outer chain axial direction, and a second axial gap is formed between the above-mentioned fourth inner chain surface of the above-mentioned third inner chain end portion and the above-mentioned third outer chain surface of the above-mentioned third outer chain end portion. In this way, relative to the above-mentioned fourth inner chain surface of the above-mentioned second inner chain middle portion, at least a part is offset toward the axial center plane of the above-mentioned bicycle chain. For the bicycle chain according to the above-mentioned second aspect, the wear resistance is improved by the bushing structure, and, due to the formation of the axial gap, the bicycle chain is easily bent, and the shifting performance is excellent.

[0008] In the bicycle chain according to the third aspect that complies with the above-mentioned first or second aspect, the above-mentioned first axial gap falls within the range of 0.05 mm to 0.15 mm. For the bicycle chain according to the above-mentioned third aspect, the wear resistance is improved by the bushing structure, and, due to the formation of the axial gap, the bicycle chain is easily bent, and the shifting performance is excellent.

[0009] In the bicycle chain according to the fourth aspect that complies with the above-mentioned second aspect, the above-mentioned second axial gap falls within the range of 0.05 mm to 0.15 mm. For the bicycle chain according to the above-mentioned fourth aspect, the wear resistance is improved by the bushing structure, and, due to the formation of the axial gap, the bicycle chain is easily bent, and the shifting performance is excellent.

[0010] In the bicycle chain according to the fifth aspect that complies with any one of the above first to fourth aspects, the first axial gap is configured to promote buckling of the bicycle chain in at least one of the first inner chain axial direction, the second inner chain axial direction, the first outer chain axial direction, and the second outer chain axial direction during a speed change operation of the bicycle chain. According to the bicycle chain according to the fifth aspect, wear resistance is improved by a bushing structure, and the bicycle chain is easily flexed by forming an axial gap, and the speed change performance is excellent.

[0011] In the bicycle chain according to the sixth aspect that complies with the second or fourth aspect, the second axial gap is configured to promote buckling of the bicycle chain in at least one of the first inner chain axial direction, the second inner chain axial direction, the first outer chain axial direction, and the second outer chain axial direction during a speed change operation of the bicycle chain. According to the bicycle chain according to the sixth aspect, wear resistance is improved by a bushing structure, and the bicycle chain is easily flexed by forming an axial gap, and the speed change performance is excellent.

[0012] In the bicycle chain according to the seventh aspect that complies with any one of the above first to sixth aspects, the first inner link plate has a first inner link longitudinal direction center line and a first inner link transverse direction center line that extends perpendicularly to the first inner link longitudinal direction center line. The first inner link distance is defined as the distance between the first inner link center axis and the second inner link center axis in the first inner link longitudinal direction related to the first inner link longitudinal direction center line. The second inner link plate has a second inner link longitudinal direction center line and a second inner link transverse direction center line that extends perpendicularly to the second inner link longitudinal direction center line. The second inner link distance is defined as the distance between the third inner link center axis and the fourth inner link center axis in the second inner link longitudinal direction related to the second inner link longitudinal direction center line. Each of the first inner link distance and the second inner link distance falls within the range of 9 mm to 13 mm. According to the bicycle chain according to the seventh aspect, since the drive efficiency is excellent, it is more suitable for a chain for power transmission between sprockets of a bicycle.

[0013] In the bicycle chain according to the eighth aspect that complies with any one of the above first to seventh aspects, the first outer link plate has a first outer link longitudinal center line and a first outer link transverse center line that extends perpendicularly to the first outer link longitudinal center line. The first outer link distance is defined as the distance between the first outer link central axis and the second outer link central axis in the first outer link longitudinal direction related to the first outer link longitudinal center line. The second outer link plate has a second outer link longitudinal center line and a second outer link transverse center line that extends perpendicularly to the second outer link longitudinal center line. The second outer link distance is defined as the distance between the third outer link central axis and the fourth outer link central axis in the second outer link longitudinal direction related to the second outer link longitudinal center line. Each of the first outer link distance and the second outer link distance falls within the range of 9 mm to 13 mm. In the bicycle chain according to the eighth aspect, since the driving efficiency is excellent, it is more suitable for the chain for power transmission between the sprockets of a bicycle.

[0014] In the bicycle chain according to the ninth aspect that complies with any one of the above first to eighth aspects, the pin has a pin outer diameter of 3.6 mm or less. In the bicycle chain according to the ninth aspect, since the pin hole can be reduced, it is easy to ensure the rigidity of the outer link plate and the inner link plate.

[0015] In the bicycle chain according to the tenth aspect that complies with the ninth aspect, the pin outer diameter is 2.5 mm or more. In the bicycle chain according to the tenth aspect, the rigidity of the pin can be ensured.

[0016] In the bicycle chain according to the eleventh aspect that complies with any one of the above first to tenth aspects, an axial concave portion is provided on at least one of the first inner link surface of the first inner link intermediate portion and the third inner link surface of the second inner link intermediate portion. In the bicycle chain according to the eleventh aspect, even if the width of the chain is reduced due to the multi-stage of the rear sprocket assembly for a bicycle, the space required for meshing with the sprocket teeth between the inner link plates can be obtained by forming the axial concave portion.

[0017] In the bicycle chain according to the twelfth aspect that complies with any one of the above first to eleventh aspects, at least one chamfered portion is provided on at least one of the first inner link plate, the second inner link plate, the first outer link plate, and the second outer link plate. In the bicycle chain according to the twelfth aspect, the shiftability of the bicycle chain is improved.

[0018] A chain for a bicycle according to the 13th aspect of the present invention includes a first inner link plate, a second inner link plate, a first outer link plate, a second outer link plate, a bush, and a pin. The first inner link plate includes: a first inner link end portion including a first inner link opening having a first inner link central axis; a second inner link end portion including a second inner link opening having a second inner link central axis extending parallel to the first inner link central axis; a first inner link intermediate portion connecting the first inner link end portion and the second inner link end portion; a first inner link surface; and a second inner link surface disposed on the opposite side of the first inner link surface in the first inner link axial direction related to the first inner link central axis. The second inner link plate includes: a third inner link end portion including a third inner link opening having a third inner link central axis; a fourth inner link end portion including a fourth inner link opening having a fourth inner link central axis extending parallel to the third inner link central axis; a second inner link intermediate portion connecting the third inner link end portion and the fourth inner link end portion; a third inner link surface configured to face the first inner link surface of the first inner link plate in the first inner link axial direction in the assembled state of the bicycle chain; and a fourth inner link surface disposed on the opposite side of the third inner link surface in the second inner link axial direction related to the third inner link central axis. The first outer link plate is configured to be adjacent to the first inner link plate without intervening other inner link plates or other outer link plates in the assembled state of the bicycle chain. The first outer link plate includes: a first outer link end portion including a first outer link opening having a first outer link central axis; a second outer link end portion including a second outer link opening having a second outer link central axis extending parallel to the first outer link central axis; a first outer link intermediate portion connecting the first outer link end portion and the second outer link end portion; a first outer link surface; and a second outer link surface disposed on the opposite side of the first outer link surface in the first outer link axial direction related to the first outer link central axis. The second outer link plate is configured to be adjacent to the second inner link plate without intervening other inner link plates or other outer link plates in the assembled state of the bicycle chain. The second outer link plate includes: a third outer link end portion including a third outer link opening having a third outer link central axis; a fourth outer link end portion including a fourth outer link opening having a fourth outer link central axis extending parallel to the third outer link central axis; a second outer link intermediate portion connecting the third outer link end portion and the fourth outer link end portion; a third outer link surface configured to face the first outer link surface of the first outer link plate in the first outer link axial direction in the assembled state of the bicycle chain; and a fourth outer link surface disposed on the opposite side of the third outer link surface in the second outer link axial direction related to the third outer link central axis.Moreover, the above-mentioned bushing has a bushing opening and is configured to be inserted into the above-mentioned first inner chain opening and the above-mentioned third inner chain opening in the assembled state of the above-mentioned bicycle chain. The above-mentioned pin is configured to be inserted into the above-mentioned first outer chain opening and the above-mentioned third outer chain opening in the assembled state of the above-mentioned bicycle chain, and through the above-mentioned bushing opening, a first axial gap is formed between the above-mentioned second inner chain surface of the above-mentioned first inner chain end portion and the above-mentioned first outer chain surface of the above-mentioned first outer chain end portion in at least one of the above-mentioned first inner chain axial direction and the above-mentioned first outer chain axial direction. The above-mentioned first axial gap falls within the range of 0.05 mm to 0.15 mm. In the bicycle chain according to the above-mentioned 13th aspect, the wear resistance is improved by the bushing structure, and, due to the formation of the axial gap, the bicycle chain is easily bent, and the shifting performance is excellent. ;

[0019] In the bicycle chain according to the 14th aspect that complies with the above-mentioned 13th aspect, a second axial gap is formed between the above-mentioned fourth inner chain surface of the above-mentioned third inner chain end portion and the above-mentioned third outer chain surface of the above-mentioned third outer chain end portion in at least one of the above-mentioned second inner chain axial direction and the above-mentioned second outer chain axial direction. The above-mentioned second axial gap falls within the range of 0.05 mm to 0.15 mm. In the bicycle chain according to the above-mentioned 14th aspect, the wear resistance is improved by the bushing structure, and, due to the formation of the axial gap, the bicycle chain is easily bent, and the shifting performance is excellent.

[0020] In the bicycle chain according to the 15th aspect that complies with the above-mentioned 13th or 14th aspect, the above-mentioned first axial gap is configured to promote the buckling of the above-mentioned bicycle chain in at least one of the above-mentioned first inner chain axial direction, the above-mentioned second inner chain axial direction, the above-mentioned first outer chain axial direction, and the above-mentioned second outer chain axial direction during the shifting operation of the above-mentioned bicycle chain. In the bicycle chain according to the above-mentioned 15th aspect, the wear resistance is improved by the bushing structure, and, due to the formation of the axial gap, the bicycle chain is easily bent, and the shifting performance is excellent.

[0021] In the bicycle chain according to the 16th aspect that complies with the above-mentioned 14th aspect, the above-mentioned second axial gap is configured to promote the buckling of the above-mentioned bicycle chain in at least one of the above-mentioned first inner chain axial direction, the above-mentioned second inner chain axial direction, the above-mentioned first outer chain axial direction, and the above-mentioned second outer chain axial direction during the shifting operation of the above-mentioned bicycle chain. In the bicycle chain according to the above-mentioned 16th aspect, the wear resistance is improved by the bushing structure, and, due to the formation of the axial gap, the bicycle chain is easily bent, and the shifting performance is excellent.

[0022] In the bicycle chain according to the 17th aspect that complies with any one of the above 13th to 16th aspects, the above-mentioned first inner link plate has a first inner link longitudinal center line and a first inner link transverse center line that extends perpendicularly to the first inner link longitudinal center line. The first inner link distance is defined as the distance between the first inner link center axis and the second inner link center axis in the first inner link longitudinal direction related to the first inner link longitudinal center line. The above-mentioned second inner link plate has a second inner link longitudinal center line and a second inner link transverse center line that extends perpendicularly to the second inner link longitudinal center line. The second inner link distance is defined as the distance between the third inner link center axis and the fourth inner link center axis in the second inner link longitudinal direction related to the second inner link longitudinal center line. Each of the above-mentioned first inner link distance and the second inner link distance falls within the range of 9 mm to 13 mm. According to the bicycle chain according to the 17th aspect, since the driving efficiency is excellent, it is more suitable for the chain for power transmission between the sprockets of the bicycle.

[0023] In the bicycle chain according to the 18th aspect that complies with any one of the above 13th to 17th aspects, the above-mentioned first outer link plate has a first outer link longitudinal center line and a first outer link transverse center line that extends perpendicularly to the first outer link longitudinal center line. The first outer link distance is defined as the distance between the first outer link center axis and the second outer link center axis in the first outer link longitudinal direction related to the first outer link longitudinal center line. The above-mentioned second outer link plate has a second outer link longitudinal center line and a second outer link transverse center line that extends perpendicularly to the second outer link longitudinal center line. The second outer link distance is defined as the distance between the third outer link center axis and the fourth outer link center axis in the second outer link longitudinal direction related to the second outer link longitudinal center line. Each of the above-mentioned first outer link distance and the second outer link distance falls within the range of 9 mm to 13 mm. According to the bicycle chain according to the 18th aspect, since the driving efficiency is excellent, it is more suitable for the chain for power transmission between the sprockets of the bicycle.

[0024] In the bicycle chain according to the 19th aspect that complies with any one of the above 13th to 18th aspects, the above-mentioned pin has a pin outer diameter of 3.6 mm or less. According to the bicycle chain according to the 19th aspect, since the pin hole can be reduced, it is easy to ensure the rigidity of the outer link plate and the inner link plate.

[0025] In the bicycle chain according to the 20th aspect that complies with the 19th aspect, the above-mentioned pin outer diameter is 2.5 mm or more. According to the bicycle chain according to the 20th aspect, the rigidity of the pin can be ensured.

[0026] In the bicycle chain according to the 21st aspect that complies with any one of the 13th to 20th aspects described above, the axial concave portion is provided on at least one of the first inner chain surface of the first inner chain intermediate portion and the third inner chain surface of the second inner chain intermediate portion. According to the bicycle chain of the 21st aspect, even if the width of the chain is reduced due to the multi-staging of the rear sprocket assembly for bicycles, the space required for meshing with the sprocket teeth between the inner chain plates can be obtained by forming the axial concave portion.

[0027] In the bicycle chain according to the 22nd aspect that complies with any one of the 13th to 21st aspects described above, at least one chamfered portion is provided on at least one of the first inner chain plate, the second inner chain plate, the first outer chain plate, and the second outer chain plate. According to the bicycle chain of the 22nd aspect, the shiftability of the bicycle chain is improved.

[0028] A bicycle chain according to the 23rd aspect of the present invention includes a first inner link plate, a second inner link plate, a first outer link plate, a second outer link plate, a bushing, and a pin. The first inner link plate includes: a first inner link end portion including a first inner link opening having a first inner link central axis and a first annular axial protrusion surrounding the first inner link opening in the circumferential direction with respect to the first inner link central axis; a second inner link end portion including a second inner link opening having a second inner link central axis extending parallel to the first inner link central axis and a second annular axial protrusion surrounding the second inner link opening in the circumferential direction with respect to the second inner link central axis; a first inner link intermediate portion connecting the first inner link end portion and the second inner link end portion; a first inner link surface; and a second inner link surface disposed on the opposite side of the first inner link surface in the first inner link axial direction related to the first inner link central axis. The second inner link plate includes: a third inner link end portion including a third inner link opening having a third inner link central axis; a fourth inner link end portion including a fourth inner link opening having a fourth inner link central axis extending parallel to the third inner link central axis; a second inner link intermediate portion connecting the third inner link end portion and the fourth inner link end portion; a third inner link surface configured to face the first inner link surface of the first inner link plate in the first inner link axial direction in the assembled state of the bicycle chain; and a fourth inner link surface disposed on the opposite side of the third inner link surface in the second inner link axial direction related to the third inner link central axis. The first outer link plate is configured to be adjacent to the first inner link plate without intervening other inner link plates or other outer link plates in the assembled state of the bicycle chain. The first outer link plate includes: a first outer link end portion including a first outer link opening having a first outer link central axis; a second outer link end portion including a second outer link opening having a second outer link central axis extending parallel to the first outer link central axis; a first outer link intermediate portion connecting the first outer link end portion and the second outer link end portion; a first outer link surface; and a second outer link surface disposed on the opposite side of the first outer link surface in the first outer link axial direction related to the first outer link central axis. The second outer link plate is configured to be adjacent to the second inner link plate without intervening other inner link plates or other outer link plates in the assembled state of the bicycle chain. The second outer link plate includes: a third outer link end portion including a third outer link opening having a third outer link central axis; a fourth outer link end portion including a fourth outer link opening having a fourth outer link central axis extending parallel to the third outer link central axis; a second outer link intermediate portion connecting the third outer link end portion and the fourth outer link end portion; a third outer link surface configured to face the first outer link surface of the first outer link plate in the first outer link axial direction in the assembled state of the bicycle chain; and a fourth outer link surface disposed on the opposite side of the third outer link surface in the second outer link axial direction related to the third outer link central axis.Moreover, the above-mentioned bushing has a bushing opening and is configured to be inserted into the above-mentioned first inner chain opening and the above-mentioned third inner chain opening in the assembled state of the above-mentioned bicycle chain, and to contact the above-mentioned first annular axially protruding portion in the assembled state of the above-mentioned bicycle chain. The above-mentioned pin is configured to be inserted into the above-mentioned first outer chain opening and the above-mentioned third outer chain opening in the assembled state of the above-mentioned bicycle chain. According to the bicycle chain of the above-mentioned 23rd aspect, the strength of the bicycle chain in the assembled state is improved. ;

[0029] In the bicycle chain of the 24th aspect that complies with the above-mentioned 23rd aspect, the above-mentioned third inner chain end portion includes a third annular axially protruding portion that circumferentially surrounds the above-mentioned third inner chain opening with respect to the above-mentioned third inner chain central axis, and the above-mentioned fourth inner chain end portion includes a fourth annular axially protruding portion that circumferentially surrounds the above-mentioned fourth inner chain opening with respect to the above-mentioned fourth inner chain central axis. The above-mentioned bushing is configured to contact the above-mentioned third annular axially protruding portion in the assembled state of the above-mentioned bicycle chain. According to the bicycle chain of the above-mentioned 24th aspect, the strength of the bicycle chain in the assembled state is further improved.

[0030] In the bicycle chain of the 25th aspect that complies with the above-mentioned 24th aspect, an additional bushing is configured to be inserted into the above-mentioned second inner chain opening and the above-mentioned fourth inner chain opening in the assembled state of the above-mentioned bicycle chain, and the above-mentioned additional bushing is configured to contact the above-mentioned second annular axially protruding portion and the above-mentioned fourth annular axially protruding portion in the assembled state of the above-mentioned bicycle chain. According to the bicycle chain of the above-mentioned 25th aspect, the strength of the bicycle chain in the assembled state is further improved.

[0031] In the bicycle chain of the 26th aspect that complies with any one of the above-mentioned 23rd to 25th aspects, an axial concave portion is provided on at least one of the above-mentioned first inner chain surface of the above-mentioned first inner chain middle portion and the above-mentioned third inner chain surface of the above-mentioned second inner chain middle portion. According to the bicycle chain of the above-mentioned 26th aspect, even if the width of the chain is reduced due to the multi-staging of the rear sprocket assembly of the bicycle, the space required for meshing with the chain teeth between the inner chain plates can be obtained by forming the axial concave portion.

[0032] In the bicycle chain of the 27th aspect that complies with any one of the above-mentioned 23rd to 26th aspects, at least one chamfered portion is provided on at least one of the above-mentioned first inner chain plate, the above-mentioned second inner chain plate, the above-mentioned first outer chain plate, and the above-mentioned second outer chain plate. According to the bicycle chain of the above-mentioned 27th aspect, the shiftability of the bicycle chain is improved. [Advantages of the Invention]

[0033] The bicycle chain according to the present invention has excellent shifting performance. Brief Description of the Drawings

[0034] Figure 1 is a schematic view of a bicycle observed from above. Figure 2 is a perspective view of the bicycle chain according to the first embodiment. Figure 3 is a cross-sectional view of the bicycle chain according to the first embodiment along line III-III of Figure 2. Figure 4 is a side view of the bicycle chain according to the first embodiment observed from the VA direction of Figure 2. Figure 5 is a side view of the bicycle chain according to the first embodiment observed from the VB direction of Figure 2. Figure 6 is a cross-sectional view of the bicycle chain according to the first embodiment along line VI-VI of Figure 3. Figure 7 is a cross-sectional view of the bicycle chain according to the first embodiment along line VII-VII of Figure 3. Figure 8 is a cross-sectional view of the bicycle chain according to the third embodiment. Figure 9 is a cross-sectional view of the bicycle chain according to the third embodiment along line IX-IX of Figure 8. Figure 10 is a cross-sectional view of the bicycle chain according to other embodiments. Embodiments

[0035] <First Embodiment> Referring to Figure 1, a human-powered vehicle to which the bicycle chain is applied will be described. In Figure 1, a view of a human-powered vehicle, an example of which is bicycle A, observed from above is shown. Here, a human-powered vehicle means a vehicle that uses at least partially human power as the driving force, and includes a vehicle that is electrically assisted to human power. A vehicle that uses only a driving force other than human power is not included in the human-powered vehicle. In particular, a vehicle that uses only an internal combustion engine as the driving force is not included in the human-powered vehicle. Generally, a human-powered vehicle is assumed to be a small and lightweight vehicle, and is assumed to be a vehicle that does not require permission when driving on a road. The illustrated human-powered vehicle includes bicycle A. Specifically, the human-powered vehicle is bicycle A. Bicycle A includes a drive chain B.

[0036] The drive chain B is of the chain drive type. The drive chain B includes a crank assembly C for a bicycle, a sprocket for a bicycle (hereinafter referred to as "sprocket D"), and a bicycle chain 10. The sprocket D has sprocket teeth for engaging the bicycle chain 10. The sprocket D includes a front sprocket E and a rear sprocket F. The crank assembly C for a bicycle includes a crankshaft Ca rotatably supported by the frame of the bicycle A, and a pair of crank arms Cb provided at each of the two end portions of the crankshaft Ca. At the front end of each crank arm Cb, a pedal is rotatably mounted.

[0037] The front sprocket E is provided on the crankshaft Ca so as to rotate integrally with the crankshaft Ca. The rear sprocket F is provided on the hub of the rear wheel. The bicycle chain 10 is wound around the front sprocket E and the rear sprocket F. The driving force applied by the user riding the bicycle A to the pedal is transmitted to the rear wheel via the front sprocket E, the bicycle chain 10, and the rear sprocket F.

[0038] Refer to FIGS. 2 to 7 to describe the bicycle chain 10. FIG. 6 is a cross-sectional view of the bicycle chain 10 of the first embodiment along the line VI-VI of FIG. 3, and the description of the roller 24 and the additional roller 28 is omitted. FIG. 7 is a cross-sectional view of the bicycle chain 10 of the first embodiment along the line VII-VII of FIG. 3, and the description of the roller 24 and the additional roller 28 is omitted.

[0039] As shown in FIG. 2, the bicycle chain 10 includes a first inner link plate 12, a second inner link plate 14, a first outer link plate 16, a second outer link plate 18, a bushing 20, and a pin 22. Further preferably, the bicycle chain 10 includes a roller 24.

[0040] As shown in FIG. 3, the first inner link plate 12 includes: a first inner link end portion 32, which includes a first inner link opening 30 having a first inner link central axis AX1; a second inner link end portion 36, which includes a second inner link opening 34 having a second inner link central axis AX2 extending parallel to the first inner link central axis AX1; and a first inner link intermediate portion 38, which connects the first inner link end portion 32 and the second inner link end portion 36. The first inner link plate 12 further includes a first inner link surface 12A, and a second inner link surface 12B disposed on the opposite side of the first inner link surface 12A in the first inner link axial direction DA related to the first inner link central axis AX1.

[0041] As shown in FIG. 4, the first inner link plate 12 has a first inner link longitudinal center line LCA and a first inner link transverse center line LCB that extends perpendicularly to the first inner link longitudinal center line LCA. The first inner link distance LGA is defined as the distance between the first inner link central axis AX1 and the second inner link central axis AX2 in the first inner link longitudinal direction DE related to the first inner link longitudinal center line LCA.

[0042] In the present embodiment, the first inner link longitudinal center line LCA and the first inner link transverse center line LCB are defined based on the first inner link plate 12. As shown in FIG. 4, the first inner link longitudinal center line LCA is defined as the line that extends in the longitudinal direction of the first inner link plate 12 and passes through the first inner link central axis AX1 and the second inner link central axis AX2 when observing the first inner link plate 12 in the direction along the first inner link axis DA. The first inner link transverse center line LCB is defined as the line that perpendicularly intersects the first inner link longitudinal center line LCA and passes through the midpoint between the first inner link central axis AX1 and the second inner link central axis AX2.

[0043] As shown in FIG. 3, the second inner link plate 14 includes: a third inner link end portion 42 that includes a third inner link opening 40 having a third inner link central axis AX3; a fourth inner link end portion 46 that includes a fourth inner link opening 44 having a fourth inner link central axis AX4 that extends parallel to the third inner link central axis AX3; and a second inner link intermediate portion 48 that connects the third inner link end portion 42 and the fourth inner link end portion 46. The second inner link plate 14 includes: a third inner link surface 14A that is configured to face the first inner link surface 12A of the first inner link plate 12 in the first inner link axis DA in the assembled state of the bicycle chain 10; and a fourth inner link surface 14B that is disposed on the opposite side of the third inner link surface 14A in the second inner link axis DB related to the third inner link central axis AX3.

[0044] As shown in FIG. 5, the second inner link plate 14 has a second inner link longitudinal center line LCC and a second inner link transverse center line LCD that extends perpendicularly to the second inner link longitudinal center line LCC. The second inner link distance LGB is defined as the distance between the third inner link central axis AX3 and the fourth inner link central axis AX4 in the second inner link longitudinal direction DF related to the second inner link longitudinal center line LCC. Each of the first inner link distance LGA and the second inner link distance LGB falls within the range of 9 mm to 13 mm. For example, each of the first inner link distance LGA and the second inner link distance LGB is set to 12.7 mm or 10 mm.

[0045] In this embodiment, the second inner chain longitudinal center line LCC and the second inner chain transverse center line LCD are defined based on the second inner chain plate 14. As shown in FIG. 5, the second inner chain longitudinal center line LCC is defined as a line that extends in the longitudinal direction of the second inner chain plate 14 when observing the second inner chain plate 14 in the direction along the second inner chain axis DB, and passes through the line of the third inner chain central axis AX3 and the fourth inner chain central axis AX4. The second inner chain transverse center line LCD is defined as a line that perpendicularly intersects the second inner chain longitudinal center line LCC and passes through the midpoint between the third inner chain central axis AX3 and the fourth inner chain central axis AX4.

[0046] As shown in FIG. 3, on at least one of the first inner chain plate 12 and the second inner chain plate 14, an axial recess 15 is provided that is recessed in the direction of the first inner chain axis DA. Specifically, the axial recess 15 is provided on at least one of the first inner chain surface 12A of the first inner chain middle portion 38 and the third inner chain surface 14A of the second inner chain middle portion 48. Preferably, the axial recess 15 is provided on both the first inner chain surface 12A of the first inner chain middle portion 38 and the third inner chain surface 14A of the second inner chain middle portion 48.

[0047] As shown in FIG. 3, the first outer chain plate 16 is configured to be adjacent to the first inner chain plate 12 without intervening other inner chain plates or other outer chain plates in the assembled state of the bicycle chain 10. The first outer chain plate 16 includes: a first outer chain end portion 52, which includes a first outer chain opening 50 having a first outer chain central axis BX1; a second outer chain end portion 56, which includes a second outer chain opening 54 having a second outer chain central axis BX2 that extends parallel to the first outer chain central axis BX1; and a first outer chain middle portion 58, which connects the first outer chain end portion 52 and the second outer chain end portion 56. The first outer chain plate 16 includes a first outer chain surface 16A and a second outer chain surface 16B that is disposed on the opposite side of the first outer chain surface 16A on the first outer chain axis DC related to the first outer chain central axis BX1.

[0048] As shown in FIG. 4, the first outer chain plate 16 has a first outer chain longitudinal center line LCE and a first outer chain transverse center line LCF that perpendicularly extends with respect to the first outer chain longitudinal center line LCE. The first outer chain distance LGC is defined as the distance between the first outer chain central axis BX1 and the second outer chain central axis BX2 on the first outer chain longitudinal direction DG related to the first outer chain longitudinal center line LCE.

[0049] In the present embodiment, the first outer link longitudinal center line LCE and the first outer link transverse center line LCF are defined based on the first outer link plate 16. As shown in FIG. 4, the first outer link longitudinal center line LCE is defined as a line that extends in the longitudinal direction in the first outer link plate 16 and passes through the first outer link central axis BX1 and the second outer link central axis BX2 when observing the first outer link plate 16 in the direction along the first outer link axial direction DC. The first outer link transverse center line LCF is defined as a line that perpendicularly intersects the first outer link longitudinal center line LCE and passes through the midpoint between the first outer link central axis BX1 and the second outer link central axis BX2.

[0050] As shown in FIG. 3, the second outer link plate 18 is configured to be adjacent to the second inner link plate 14 without intervening other inner link plates or other outer link plates in the assembled state of the bicycle chain 10. The second outer link plate 18 includes: a third outer link end portion 62 that includes a third outer link opening 60 having a third outer link central axis BX3; a fourth outer link end portion 66 that includes a fourth outer link opening 64 having a fourth outer link central axis BX4 that extends parallel to the third outer link central axis BX3; and a second outer link intermediate portion 68 that connects the third outer link end portion 62 and the fourth outer link end portion 66. The second outer link plate 18 includes: a third outer link surface 18A that is configured to face the first outer link surface 16A of the first outer link plate 16 on the first outer link axial direction DC in the assembled state of the bicycle chain 10; and a fourth outer link surface 18B that is disposed on the opposite side of the third outer link surface 18A on the second outer link axial direction DD related to the third outer link central axis BX3.

[0051] As shown in FIG. 5, the second outer link plate 18 has a second outer link longitudinal center line LCG and a second outer link transverse center line LCH that perpendicularly extends with respect to the second outer link longitudinal center line LCG. The second outer link distance LGD is defined as the distance between the third outer link central axis BX3 and the fourth outer link central axis BX4 in the second outer link longitudinal direction DH related to the second outer link longitudinal center line LCG. Each of the first outer link distance LGC and the second outer link distance LGD falls within the range of 9 mm to 13 mm. Each of the first outer link distance LGC and the second outer link distance LGD is set to 12.7 mm or 10 mm.

[0052] In the present embodiment, the second outer link longitudinal center line LCG and the second outer link transverse center line LCH are defined based on the second outer link plate 18. As shown in FIG. 5, the second outer chain longitudinal center line LCG is defined as a line that extends in the longitudinal direction in the second outer chain plate 18 when observing the second outer chain plate 18 in the direction along the axial direction DD of the second outer chain, and passes through the third outer chain central axis BX3 and the fourth outer chain central axis BX4. The second outer chain transverse center line LCH is defined as a line that perpendicularly intersects the second outer chain longitudinal center line LCG and passes through the midpoint between the third outer chain central axis BX3 and the fourth outer chain central axis BX4.

[0053] Preferably, at least one chamfer portion 70 is provided on at least one of the first inner chain plate 12, the second inner chain plate 14, the first outer chain plate 16, and the second outer chain plate 18.

[0054] As shown in FIG. 6, the chamfer portion 70 can be provided on the first inner chain surface 12A of the first inner chain end portion 32 and the second inner chain end portion 36 of the first inner chain plate 12. As shown in FIG. 7, the chamfer portion 70 can be provided on the third inner chain surface 14A of the third inner chain end portion 42 and the fourth inner chain end portion 46 of the second inner chain plate 14. As shown in FIG. 4, the chamfer portion 70 can be provided on the second outer chain surface 16B of the first outer chain end portion 52 and the second outer chain end portion 56 of the first outer chain plate 16. As shown in FIG. 5, the chamfer portion 70 can be provided on the fourth outer chain surface 18B of the third outer chain end portion 62 and the fourth outer chain end portion 66 of the second outer chain plate 18.

[0055] As shown in FIG. 3, the bushing 20 has a bushing opening 20A. The bushing 20 is configured to be inserted into the first inner chain opening 30 and the third inner chain opening 40 in the assembled state of the bicycle chain 10. The additional bushing 26 has an additional bushing opening 26A. The additional bushing 26 is configured to be inserted into the second inner chain opening 34 and the fourth inner chain opening 44 in the assembled state of the bicycle chain 10. The bushing 20 and the additional bushing 26 can have the same structure or different structures.

[0056] As shown in FIG. 3, the pin 22 is configured to be inserted into the first outer link opening 50 and the third outer link opening 60 and pass through the bushing opening 20A in the assembled state of the bicycle chain 10. Preferably, the pin 22 is press-fitted and inserted into the first outer link opening 50 and the third outer link opening 60 in the assembled state of the bicycle chain 10. The additional pin 23 is configured to be inserted into the second outer link opening 54 and the fourth outer link opening 64 and pass through the additional bushing opening 26A of the additional bushing 26 in the assembled state of the bicycle chain 10. Preferably, the additional pin 23 is press-fitted and inserted into the second outer link opening 54 and the fourth outer link opening 64 in the assembled state of the bicycle chain 10. Preferably, the pin 22 has a pin outer diameter of 3.6 mm or less. More preferably, the pin outer diameter is 2.5 mm or more. Preferably, the additional pin 23 has an additional pin outer diameter of 3.6 mm or less. Preferably, the additional pin outer diameter is 2.5 mm or more.

[0057] The first outer link plate 16 and the second outer link plate 18 are joined by the pin 22 and the additional pin 23. The first inner link plate 12 and the second inner link plate 14 are joined by the bushing 20 and the additional bushing 26. The combination of the first inner link plate 12 and the second inner link plate 14 is rotatably connected to the combination of the first outer link plate 16 and the second outer link plate 18 about the central axis of the pin 22 and the central axis of the additional pin 23. The combination including the first inner link plate 12 and the second inner link plate 14 and the combination including the first outer link plate 16 and the second outer link plate 18 are alternately arranged and connected in a ring shape.

[0058] As shown in FIG. 3, the roller 24 is disposed between the first inner link plate 12 and the second inner link plate 14. One roller 24 has a roller opening 24A through which the bushing 20 is inserted. The roller 24 is relatively rotatable with respect to the bushing 20. The additional roller 28 has an additional roller opening 28A through which the additional bushing 26 is inserted. The additional roller 28 is relatively rotatable with respect to the additional bushing 26.

[0059] The roller 24 is disposed between the first inner link end portion 32 of the first inner link plate 12 and the third inner link end portion 42 of the second inner link plate 14. The additional roller 28 is disposed between the second inner link end portion 36 of the first inner link plate 12 and the fourth inner link end portion 46 of the second inner link plate 14. When the bicycle chain 10 is installed on the bicycle A, the roller 24 and the additional roller 28 come into contact with the sprocket teeth.

[0060] Next, the structure between the first inner link plate 12 and the first outer link plate 16 and the structure between the second inner link plate 14 and the second outer link plate 18 will be described.

[0061] As shown in FIG. 3, the second inner chain surface 12B of the first inner chain end portion 32 is offset at least partially toward the axial center plane 10A of the bicycle chain 10 with respect to the second inner chain surface 12B of the first inner chain intermediate portion 38 in such a manner that a first axial gap SA is formed between the second inner chain surface 12B of the first inner chain end portion 32 and the first outer chain surface 16A of the first outer chain end portion 52 in at least one of the first inner chain axial direction DA and the first outer chain axial direction DC.

[0062] The first axial gap SA falls within the range of 0.05 mm to 0.15 mm. The first axial gap SA is defined as the distance between the second inner chain surface 12B of the first inner chain end portion 32 and the first outer chain surface 16A of the first outer chain end portion 52 in the first inner chain axial direction DA. The first axial gap SA is configured to promote buckling of the bicycle chain 10 in at least one of the first inner chain axial direction DA, the second inner chain axial direction DB, the first outer chain axial direction DC, and the second outer chain axial direction DD during a shifting operation of the bicycle chain 10.

[0063] The first outer chain end portion 52 of the first outer chain plate 16 is disposed at a portion of the second inner chain surface 12B of the first inner chain end portion 32 that is offset toward the axial center plane 10A of the bicycle chain 10.

[0064] The first inner chain end portion 32 is divided into a first bushing surrounding portion 32A around the bushing 20 and a first outer peripheral portion 32B around the first bushing surrounding portion 32A. The second inner chain surface 12B of the first outer peripheral portion 32B is offset at least partially toward the axial center plane 10A of the bicycle chain 10 with respect to the second inner chain surface 12B of the first inner chain intermediate portion 38 in at least one of the first inner chain axial direction DA and the first outer chain axial direction DC. The second inner chain surface 12B of the first bushing surrounding portion 32A is offset toward the axial center plane 10A of the bicycle chain 10 with respect to the second inner chain surface 12B of the first outer peripheral portion 32B in at least one of the first inner chain axial direction DA and the first outer chain axial direction DC. Preferably, the second inner chain surface 12B of the first bushing surrounding portion 32A is the same surface as the first bushing end face 20B of the bushing 20 disposed on the first inner chain plate 12 side. A gap is provided between the first bushing end face 20B of the bushing 20 and the first outer chain surface 16A of the first outer chain end portion 52 of the first outer chain plate 16.

[0065] As shown in FIG. 3, the fourth inner chain surface 14B of the third inner chain end portion 42 is offset at least partially toward the axial center plane 10A of the bicycle chain 10 with respect to the fourth inner chain surface 14B of the second inner chain intermediate portion 48 in such a manner that a second axial gap SB is formed between the fourth inner chain surface 14B of the third inner chain end portion 42 and the third outer chain surface 18A of the third outer chain end portion 62 on at least one of the second inner chain axial direction DB and the second outer chain axial direction DD.

[0066] The second axial gap SB falls within the range of 0.05 mm to 0.15 mm. The second axial gap SB is defined as the distance between the fourth inner chain surface 14B of the third inner chain end portion 42 and the third outer chain surface 18A of the third outer chain end portion 62 on the second inner chain axial direction DB. The second axial gap SB is configured to promote buckling of the bicycle chain 10 on at least one of the first inner chain axial direction DA, the second inner chain axial direction DB, the first outer chain axial direction DC, and the second outer chain axial direction DD during a shifting operation of the bicycle chain 10.

[0067] The third outer chain end portion 62 of the second outer chain plate 18 is disposed at a portion of the fourth inner chain surface 14B of the third inner chain end portion 42 that is offset toward the axial center plane 10A of the bicycle chain 10.

[0068] The third inner chain end portion 42 is divided into a second bushing surrounding portion 42A around the bushing 20 and a second outer peripheral portion 42B around the second bushing surrounding portion 42A. The fourth inner chain surface 14B of the second outer peripheral portion 42B is offset at least partially toward the axial center plane 10A of the bicycle chain 10 with respect to the fourth inner chain surface 14B of the second inner chain intermediate portion 48 on at least one of the first inner chain axial direction DA and the first outer chain axial direction DC. The fourth inner chain surface 14B of the second bushing surrounding portion 42A is offset toward the axial center plane 10A of the bicycle chain 10 with respect to the fourth inner chain surface 14B of the second outer peripheral portion 42B on at least one of the first inner chain axial direction DA and the first outer chain axial direction DC. Preferably, the fourth inner chain surface 14B of the second bushing surrounding portion 42A and the second bushing end face 20C of the bushing 20 disposed on the second inner chain plate 14 side are the same plane. A gap is provided between the second bushing end face 20C of the bushing 20 and the third outer chain surface 18A of the third outer chain end portion 62 of the second outer chain plate 18.

[0069] When a force is applied to the bicycle chain 10 by the shifting operation of the bicycle A, at least one of the first axial gap SA and the second axial gap SB is provided in the bicycle chain 10, so that the first inner link plate 12 and the second inner link plate 14 are displaced relative to the first outer link plate 16 and the second outer link plate 18 in the direction along any one of the first inner link axial direction DA, the second inner link axial direction DB, the first outer link axial direction DC, and the second outer link axial direction DD. By this kind of action, the bending of the bicycle chain 10 is facilitated. It is preferable to provide both the first axial gap SA and the second axial gap SB in the bicycle chain 10.

[0070] <Second Embodiment> The bicycle chain 10 of the second embodiment will be described. Regarding the components common to the first embodiment, the same reference numerals as those in the first embodiment are used, and the repeated descriptions are omitted. The bicycle chain 10 of the second embodiment includes the structure of the first axial gap SA and the second axial gap SB shown in the first embodiment, and the structure other than the structure of the first axial gap SA and the second axial gap SB shown in the first embodiment.

[0071] As shown in FIG. 3, the first axial gap SA is formed between the second inner link surface 12B of the first inner link end portion 32 and the first outer link surface 16A of the first outer link end portion 52 on at least one of the first inner link axial direction DA and the first outer link axial direction DC. The first axial gap SA falls within the range of 0.05 mm to 0.15 mm.

[0072] For example, the first outer link surface 16A of the first outer link end portion 52 can also be offset at least partially in a direction opposite to the direction leading to the axial center plane 10A of the bicycle chain 10 relative to the first outer link surface 16A of the first outer link intermediate portion 58 in such a manner that the first axial gap SA is formed between the second inner link surface 12B of the first inner link end portion 32 and the first outer link surface 16A of the first outer link end portion 52 on at least one of the first inner link axial direction DA and the first outer link axial direction DC.

[0073] Furthermore, as shown in the first embodiment, the second inner link surface 12B of the first inner link end portion 32 can also be offset at least partially toward the axial center plane 10A of the bicycle chain 10 relative to the second inner link surface 12B of the first inner link intermediate portion 38 in such a manner that the first axial gap SA is formed between the second inner link surface 12B of the first inner link end portion 32 and the first outer link surface 16A of the first outer link end portion 52 on at least one of the first inner link axial direction DA and the first outer link axial direction DC. If a first axial gap SA is formed between a second inner link surface 12B of the first inner link end portion 32 and a first outer link surface 16A of the first outer link end portion 52, the second inner link surface 12B of the first inner link plate 12 can also be formed flatly from the first inner link end portion 32 through the first inner link intermediate portion 38 to the second inner link end portion 36.

[0074] The first axial gap SA is configured to promote buckling of the bicycle chain 10 on at least one of a first inner link axial direction DA, a second inner link axial direction DB, a first outer link axial direction DC, and a second outer link axial direction DD during a shifting operation of the bicycle chain 10.

[0075] As shown in FIG. 3, a second axial gap SB is formed between a fourth inner link surface 14B of a third inner link end portion 42 and a third outer link surface 18A of a third outer link end portion 62 on at least one of the second inner link axial direction DB and the second outer link axial direction DD. The second axial gap SB falls within a range of 0.05 mm to 0.15 mm.

[0076] For example, the third outer link surface 18A of the third outer link end portion 62 can also be offset at least partially in a direction opposite to the direction leading to the axial center plane 10A of the bicycle chain 10 with respect to the third outer link surface 18A of the second outer link intermediate portion 68 in such a manner that the second axial gap SB is formed between the fourth inner link surface 14B of the third inner link end portion 42 and the third outer link surface 18A of the third outer link end portion 62 on at least one of the second inner link axial direction DB and the second outer link axial direction DD.

[0077] Furthermore, as shown in the first embodiment, the fourth inner link surface 14B of the third inner link end portion 42 can also be offset at least partially toward the axial center plane 10A of the bicycle chain 10 with respect to the fourth inner link surface 14B of the second inner link intermediate portion 48 in such a manner that the second axial gap SB is formed between the fourth inner link surface 14B of the third inner link end portion 42 and the third outer link surface 18A of the third outer link end portion 62 on at least one of the second inner link axial direction DB and the second outer link axial direction DD. If a second axial gap SB is formed between the fourth inner link surface 14B of the third inner link end portion 42 and the third outer link surface 18A of the third outer link end portion 62, the fourth inner link surface 14B of the second inner link plate 14 can also be formed flatly from the third inner link end portion 42 through the second inner link intermediate portion 48 to the fourth inner link end portion 46.

[0078] The second axial gap SB is configured to promote buckling of the bicycle chain 10 on at least one of the first inner chain axial direction DA, the second inner chain axial direction DB, the first outer chain axial direction DC, and the second outer chain axial direction DD during the shifting operation of the bicycle chain 10.

[0079] Furthermore, each of the first inner chain distance LGA and the second inner chain distance LGB may also fall within the range of 9 mm to 13 mm. Each of the first outer chain distance LGC and the second outer chain distance LGD may also fall within the range of 9 mm to 13 mm. For example, each of the first inner chain distance LGA, the second inner chain distance LGB, the first outer chain distance LGC, and the second outer chain distance LGD is set to 12.7 mm or 10 mm.

[0080] Furthermore, the pin 22 may also have a pin outer diameter of 3.6 mm or less. The pin outer diameter may also be 2.5 mm or more.

[0081] Furthermore, the axial recess 15 may be provided on at least one of the first inner chain surface 12A of the first inner chain intermediate portion 38 and the third inner chain surface 14A of the second inner chain intermediate portion 48.

[0082] Furthermore, at least one chamfered portion 70 may be provided on at least one of the first inner link plate 12, the second inner link plate 14, the first outer link plate 16, and the second outer link plate 18.

[0083] <Third Embodiment> Referring to FIGS. 8 and 9, the bicycle chain 10 of the third embodiment will be described. Regarding the components common to the third embodiment, the same reference numerals as those in the first embodiment are given, and the repeated description is omitted. The difference between the bicycle chain 10 of the third embodiment and the bicycle chain 10 of the first embodiment lies in the coupling structure of the first inner link plate 12 and the second inner link plate 14 with the bush 20 and the additional bush 26.

[0084] The first inner chain end portion 32 includes: a first inner chain opening 30 having a first inner chain central axis AX1; and a first annular axial protrusion 84 that circumferentially surrounds the first inner chain opening 30 with respect to the first inner chain central axis AX1. The second inner chain end portion 36 includes: a second inner chain opening 34 having a second inner chain central axis AX2 that extends parallel to the first inner chain central axis AX1; and a second annular axial protrusion 86 that circumferentially surrounds the second inner chain opening 34 with respect to the second inner chain central axis AX2.

[0085] The bush 20 has a bush opening 20A. The bush 20 is configured to be inserted into the first inner chain opening 30 and the third inner chain opening 40 in the assembled state of the bicycle chain 10, and to contact the first annular axially projecting portion 84 in the assembled state of the bicycle chain 10. The pin 22 is configured to be inserted into the first outer chain opening 50 and the third outer chain opening 60 in the assembled state of the bicycle chain 10. The additional pin 23 is configured to be inserted into the second outer chain opening 54 and the fourth outer chain opening 64 in the assembled state of the bicycle chain 10. The pin 22 is configured to pass through the bush opening 20A. The additional pin 23 is configured to pass through the additional bush opening 26A.

[0086] The third inner chain end portion 42 includes a third annular axially projecting portion 88 that circumferentially surrounds the third inner chain opening 40 about the third inner chain central axis AX3. The fourth inner chain end portion 46 includes a fourth annular axially projecting portion 90 that circumferentially surrounds the fourth inner chain opening 44 about the fourth inner chain central axis AX4. The bush 20 is configured to contact the third annular axially projecting portion 88 in the assembled state of the bicycle chain 10.

[0087] The additional bush 26 is configured to be inserted into the second inner chain opening 34 and the fourth inner chain opening 44 in the assembled state of the bicycle chain 10. The additional bush 26 is configured to contact the second annular axially projecting portion 86 and the fourth annular axially projecting portion 90 in the assembled state of the bicycle chain 10.

[0088] Furthermore, the axial recess 15 may be provided in at least one of the first inner chain surface 12A of the first inner chain intermediate portion 38 and the third inner chain surface 14A of the second inner chain intermediate portion 48. Preferably, the axial recess 15 is provided in both the first inner chain surface 12A of the first inner chain intermediate portion 38 and the third inner chain surface 14A of the second inner chain intermediate portion 48.

[0089] As shown in FIG. 8, the roller 24 and the additional roller 28 are disposed between the first inner chain plate 12 and the second inner chain plate 14. The roller 24 is disposed between the first inner chain end portion 32 of the first inner chain plate 12 and the third inner chain end portion 42 of the second inner chain plate 14. The additional roller 28 is disposed between the second inner chain end portion 36 of the first inner chain plate 12 and the fourth inner chain end portion 46 of the second inner chain plate 14.

[0090] The roller 24 has a roller opening 24A through which the first annular axial protrusion 84 and the third annular axial protrusion 88 are inserted. The roller 24 is rotatable relative to the first annular axial protrusion 84 and the third annular axial protrusion 88. The additional roller 28 has an additional roller opening 28A through which the second annular axial protrusion 86 and the fourth annular axial protrusion 90 are inserted. The additional roller 28 is rotatable relative to the second annular axial protrusion 86 and the fourth annular axial protrusion 90.

[0091] <Examples of variations thereof> The description of each embodiment is based on an example of the bicycle chain 10 according to the present invention and is not intended to limit its form. The bicycle chain 10 according to the present invention can take, for example, variations of the embodiments shown below, and forms combined from at least two variations that are not mutually contradictory. In the following variations, for parts common to the forms of the embodiments, the same reference numerals as those in the embodiments are given and the description thereof is omitted.

[0092] · At least one of the first chamfered portions 92 to the fourth chamfered portions 98 may be provided at the edge of the first outer link plate 16 and the edge of the second outer link plate 18 in each embodiment. The first chamfered portions 92 to the fourth chamfered portions 98 include a flat surface and a curved surface. As shown in FIG. 10, the first chamfered portion 92 may also be provided between the first end surface 52A of the first outer link end portion 52 of the first outer link plate 16 and the first outer link surface 16A in the first outer link end portion 52. The second chamfered portion 94 may also be provided between the second end surface 56A of the second outer link end portion 56 of the first outer link plate 16 and the first outer link surface 16A in the second outer link end portion 56. The third chamfered portion 96 may also be provided between the third end surface 62A of the third outer link end portion 62 of the second outer link plate 18 and the third outer link surface 18A in the third outer link end portion 62. The fourth chamfered portion 98 may also be provided between the fourth end surface 66A of the fourth outer link end portion 66 of the second outer link plate 18 and the third outer link surface 18A in the fourth outer link end portion 66.

[0093] 10: Bicycle chain 10A: Axial center plane 12: First inner link plate 12A: First inner link surface 12B: Second inner link surface 14: Second inner link plate 14A: Third inner link surface 14B: Fourth inner link surface 15: Axial concave portion 16: First outer link plate 16A: First outer link surface 16B: Second outer link surface 18: Second outer link plate 18A: Third outer link surface 18B: Fourth outer link surface 20: Bush 20A: Bush opening 20B: First bush end face 20C: Second bush end face 22: Pin 23: Additional pin 24: Roller 24A: Roller opening 26: Additional bush 26A: Additional bush opening 28: Additional roller 28A: Additional roller opening 30: First inner link opening 32: First inner link end 32A: First bush surrounding part 32B: First outer peripheral part 34: Second inner link opening 36: Second inner link end 38: First inner link middle part 40: Third inner link opening 42: Third inner link end 42A: Second bush surrounding part 42B: Second outer peripheral part 44: Fourth inner link opening 46: Fourth inner link end 48: Second inner link middle part 50: First outer link opening 52: First outer link end 52A: First end face 54: Second outer link opening 56: Second outer link end 56A: Second end face 58: First outer link middle part 60: Third outer link opening 62: Third outer link end 62A: Third end face 64: Fourth outer link opening 66: Fourth outer link end 66A: Fourth end face 68: Second outer chain middle part 70: Chamfered part 84: First annular axial protrusion 86: Second annular axial protrusion 88: Third annular axial protrusion 90: Fourth annular axial protrusion 92: First chamfered part 94: Second chamfered part 96: Third chamfered part 98: Fourth chamfered part A: Bicycle AX1: First inner chain central axis AX2: Second inner chain central axis AX3: Third inner chain central axis AX4: Fourth inner chain central axis B: Transmission chain BX1: First outer chain central axis BX2: Second outer chain central axis BX3: Third outer chain central axis BX4: Fourth outer chain central axis C: Bicycle crank assembly Ca: Crankshaft Cb: Crank arm D: Bicycle sprocket DA: First inner chain axial direction DB: Second inner chain axial direction DC: First outer chain axial direction DD: Second outer chain axial direction DE: First inner chain longitudinally long direction DF: Second inner chain longitudinally long direction DG: First outer chain longitudinally long direction DH: Second outer chain longitudinally long direction E: Front sprocket F: Rear sprocket III-III: Line IX-IX: Line LCA: First inner chain longitudinally long direction center line LCB: First inner chain transversely long direction center line LCC: Second inner chain longitudinally long direction center line LCD: Second inner chain transversely long direction center line LCE: First outer chain longitudinally long direction center line LCF: First outer chain horizontal length direction center line LCG: Second outer chain vertical length direction center line LCH: Second outer chain horizontal length direction center line LGA: First inner chain distance LGB: Second inner chain distance LGC: First outer chain distance LGD: Second outer chain distance SA: First axial gap SB: Second axial gap VA: Direction VB: Direction VI-VI: Line VII-VII: Line

Claims

1. A bicycle chain comprising a first inner chain plate, a second inner chain plate, a first outer chain plate, a second outer chain plate, a bushing, and a pin; wherein the first inner chain plate comprises: a first inner chain end portion having a first inner chain opening having a first inner chain central axis, and a first annular axial protrusion surrounding the first inner chain opening in a circumferential direction with respect to the first inner chain central axis; a second inner chain end portion having a second inner chain opening having a second inner chain central axis extending parallel to the first inner chain central axis, and a second annular axial protrusion surrounding the second inner chain opening in a circumferential direction with respect to the second inner chain central axis; a first inner chain middle portion connecting the first inner chain end portion and the second inner chain end portion; a first inner chain surface; and a second inner chain surface disposed axially on the opposite side of the first inner chain surface in a first inner chain axial direction related to the first inner chain central axis; and the second inner chain plate comprises: The third inner chain end includes a third inner chain opening having a third inner chain central axis; the fourth inner chain end includes a fourth inner chain opening having a fourth inner chain central axis extending parallel to the third inner chain central axis; the second inner chain middle portion connects the third inner chain end and the fourth inner chain end; the third inner chain surface is configured to face the first inner chain surface of the first inner chain plate upwards along the first inner chain axis in the assembled state of the bicycle chain; and the fourth inner chain surface is disposed on the opposite side of the third inner chain surface along the second inner chain axis related to the third inner chain central axis; and the first outer chain plate is configured to be adjacent to the first inner chain plate without separating it from other inner chain plates or other outer chain plates in the assembled state of the bicycle chain; the first outer chain plate includes: a first outer chain end including a first outer chain opening having a first outer chain central axis. The second outer chain end includes a second outer chain opening having a second outer chain central axis extending parallel to the central axis of the first outer chain; a first outer chain middle portion connecting the first outer chain end and the second outer chain end; a first outer chain surface; and a second outer chain surface disposed axially upward on the opposite side of the first outer chain surface along the first outer chain axis related to the central axis of the first outer chain; and the second outer chain plate is configured to be adjacent to the second inner chain plate without separating it from other inner chain plates or other outer chain plates in the assembled state of the bicycle chain; the second outer chain plate includes: a third outer chain end including a third outer chain opening having a third outer chain central axis; a fourth outer chain end including a fourth outer chain opening having a fourth outer chain central axis extending parallel to the central axis of the third outer chain; and a second outer chain middle portion connecting the third outer chain end and the fourth outer chain end. The third outer chain surface is configured such that, in the assembled state of the bicycle chain, the first outer chain surface faces the first outer chain plate axially upwards from the first outer chain surface; and the fourth outer chain surface is disposed on the opposite side of the third outer chain surface axially upwards from the second outer chain surface related to the central axis of the third outer chain.The bushing has a bushing opening and is configured to be inserted into the first inner chain opening and the third inner chain opening in the assembled state of the bicycle chain, and to contact the first annular axial protrusion in the assembled state of the bicycle chain; the pin is configured to be inserted into the first outer chain opening and the third outer chain opening in the assembled state of the bicycle chain; the first annular axial protrusion protrudes toward the axial center plane of the bicycle chain; the third inner chain end includes a third annular axial protrusion that surrounds the third inner chain opening circumferentially around the central axis of the third inner chain; the first annular axial protrusion of the first inner chain plate and the third annular axial protrusion of the second inner chain plate directly face each other; the free ends of the first annular axial protrusion and the free ends of the third annular axial protrusion are axially separated from each other in the first inner chain.

2. The bicycle chain of claim 1, wherein the fourth inner chain end includes a fourth annular axial protrusion that surrounds the opening of the fourth inner chain in the circumferential direction about the central axis of the fourth inner chain; the bushing is configured to contact the first annular axial protrusion and the third annular axial protrusion in the assembled state of the bicycle chain; the first annular axial protrusion and the third annular axial protrusion are inserted into a roller having a roller opening.

3. The bicycle chain of claim 2, wherein the additional bushing is configured to be inserted into the second inner chain opening and the fourth inner chain opening in the assembled state of the bicycle chain; the additional bushing is configured to contact the second annular axial protrusion and the fourth annular axial protrusion in the assembled state of the bicycle chain; the second annular axial protrusion and the fourth annular axial protrusion are inserted into an additional roller having an additional roller opening.

4. A bicycle chain as claimed in any of claims 1 to 3, wherein an axial recess is provided on at least one of the first inner chain surface of the middle portion of the first inner chain and the third inner chain surface of the middle portion of the second inner chain.

5. A bicycle chain as claimed in any of claims 1 to 3, wherein at least one chamfer is provided on at least one of the first inner chain plate, the second inner chain plate, the first outer chain plate, and the second outer chain plate.

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