Bicycle chain

Abstract

To prevent a deterioration of the efficiency of driving a front sprocket and a rear sprocket of a bicycle and prevent loosening of a bicycle chain.SOLUTION: A bicycle chain has a plurality of inner link plates, a plurality of outer link plates, and a plurality of pins. The plurality of pins each have, on the whole or part of its outer peripheral surface, a pin cured layer containing at least one of Cr carbide, Ti carbide, V carbide, Nb carbide, Cr nitride, Ti nitride, V nitride and Nb nitride.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to bicycle chains. [Background technology]

[0002] Patent Document 1 discloses a technique related to a bicycle chain. The chain in Patent Document 1 has alternating, continuous outer links and inner links, which are connected to each other at their connection ends with rivets. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-105438 Summary of the Invention [Problem to be solved by the invention]

[0004] In order to prevent a decrease in the efficiency of driving the front and rear sprockets of a bicycle and to prevent slack in the bicycle chain, it is preferable that at least one of the parts that slide against each other when the bicycle chain is in use has high wear resistance. [Means for solving the problem]

[0005] A bicycle chain according to a first aspect of the present disclosure is a bicycle chain including a plurality of inner link plates, a plurality of outer link plates, and a plurality of pins, the plurality of inner link plates include a first inner link plate and a second inner link plate, the plurality of outer link plates include a first outer link plate and a second outer link plate, the plurality of pins include a first pin, and the first inner link plate comprises 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 a 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 a 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 disposed on the opposite side to the first inner link surface in the first inner link axial direction with respect to the first inner link central axis. a third inner link end portion including a third inner link opening having a third inner link central axis and a third annular axial protrusion circumferentially surrounding the third inner link opening with respect to the third inner link central axis; and a third inner link end portion including a third inner link opening having a third inner link central axis and a third annular axial protrusion circumferentially surrounding the third inner link opening with respect to the 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 in a direction perpendicular to the first inner link axis, and a fourth annular axial protrusion circumferentially surrounding the fourth inner link opening relative to the fourth inner link central axis; a second inner link intermediate portion connecting the third inner link end portion and the fourth inner link end portion; and a third inner link face configured to face the first inner link face of the first inner link plate in the first inner link axial direction when the bicycle chain is assembled.and a fourth inner link surface disposed on the opposite side of the third inner link surface in a second inner link axial direction relative to the third inner link central axis, the third annular axial protrusion having a third proximal end connected to the third inner link surface and a third distal end disposed opposite the first distal end of the first annular axial protrusion in an assembled state of the bicycle chain, the fourth annular axial protrusion having a fourth proximal end connected to the third inner link surface and a fourth distal end disposed opposite the second distal end of the second annular axial protrusion in an assembled state of the bicycle chain, the first outer link plate being configured to be adjacent to the first inner link plate without another inner link plate or another outer link plate interposed therebetween in the assembled state of the bicycle chain, the first outer link plate having a first outer link end portion including a first outer link opening having a first outer link central axis and a second outer link middle portion extending parallel to the first outer link central axis. a second outer link end portion including a second outer link opening having a 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 relative to the first outer link central axis, wherein the second outer link plate is configured to be adjacent to the second inner link plate without interposing another inner link plate or another outer link plate therebetween, and 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; and a second outer link intermediate portion connecting the third outer link end portion and the fourth outer link end portion, and wherein, when the bicycle chain is assembled,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, and a fourth outer link surface positioned on the opposite side of the third outer link surface in the second outer link axial direction relative to the third outer link central axis, wherein the first pin is configured to be inserted through the first outer link opening, the third outer link opening, the first inner link opening, and the third inner link opening when the bicycle chain is in an assembled state, and has a first outer peripheral surface that slides against the first annular axial protrusion and the third annular axial protrusion when the bicycle chain is in use; The bicycle chain includes a plurality of pins having a pin-hardened layer containing any one of Ti carbide, Nb carbide, Cr nitride, and Ti nitride on a part or all of the outer circumferential surface. According to the bicycle chain of the first aspect, the pin hardened layer improves the wear resistance of the pins, suppresses chain elongation, and improves drive efficiency. In addition, the wear resistance of a bicycle chain comprising a first inner link plate, a second inner link plate, a first outer link plate, a second outer link plate, and a first pin is improved, chain elongation is suppressed, and driving efficiency is improved.

[0006] In a bicycle chain according to a second aspect of the present disclosure, the pin hardened layer has a sliding surface hardness of 1000 HV or more and 3500 HV or less. According to the bicycle chain relating to the second feature, the wear resistance of the pins is further improved, chain elongation is suppressed, and drive efficiency is improved compared to chains with a sliding surface hardness of the pin hardened layer outside the above range.

[0007] In a bicycle chain according to a third feature of the present disclosure, the inner link plates have inner link sliding surfaces that slide against the outer peripheral surfaces of the pins, and the sliding surface hardness of the pin hardened layer is greater than the surface hardness of the inner link sliding surfaces. In the bicycle chain according to the third feature described above, the wear resistance of the pin is further improved compared to a chain in which the sliding surface hardness of the pin hardened layer is equal to or lower than the surface hardness of the inner link sliding surface, thereby suppressing chain elongation and improving drive efficiency.

[0008] A fourth feature of the present disclosure relates to a bicycle chain in which the multiple inner link plates have inner link sliding surfaces that slide against the outer peripheral surfaces of the pins, and a link hardening layer including any one of Cr carbide, Ti carbide, V carbide, Nb carbide, Cr nitride, Ti nitride, V nitride, and Nb nitride is formed on part or all of the inner link sliding surfaces. According to the bicycle chain of the fourth feature, the pin wear resistance is further improved, chain elongation is suppressed, and drive efficiency is improved compared to bicycle chains that do not have a link hardening layer containing any one of Cr carbide, Ti carbide, V carbide, Nb carbide, Cr nitride, Ti nitride, V nitride, and Nb nitride.

[0009] In a bicycle chain according to a fifth feature of the present disclosure, the inner link plates have inner link sliding surfaces that slide against the outer peripheral surfaces of the pins, and the surface roughness of the pin hardened layer is less than the surface roughness of the inner link sliding surfaces. In the bicycle chain according to the fifth feature, the surface roughness of the pin hardened layer is greater than or equal to the surface roughness of the inner link sliding surface, which further improves the pin's wear resistance, suppresses chain elongation, and improves drive efficiency.

[0010] In a bicycle chain according to a sixth feature of the present disclosure, the plurality of pins include connecting pins for connecting the chain in an endless fashion, and the surface condition of the connecting pins is formed differently from that of the other pins. In a bicycle chain according to the sixth feature, the connecting pins are subject to more wear than the other pins, and over long periods of use the chain pitch before and after the connecting pins becomes larger than the rest of the chain, producing a clicking sensation and sound during use, which can be used by the user to determine whether the chain has stretched.

[0012] The present disclosure Seventh In the bicycle chain according to the feature of the present invention, the plurality of pins include a second pin, which is configured to be inserted through the second outer link opening, the fourth outer link opening, the second inner link opening, and the fourth inner link opening when the bicycle chain is in an assembled state, and which has a second outer surface that slides against the second annular axial protrusion and the fourth annular axial protrusion when the bicycle chain is in use. the above Seventh According to the bicycle chain having the above feature, the wear resistance of the bicycle chain equipped with the second pin is improved, chain elongation is suppressed, and driving efficiency is improved.

[0013] The present disclosure No. 8 In a bicycle chain according to the feature of the present invention, a first proximal end of the first annular axial projection is integrally connected to the first inner link face by a single material, and a second proximal end of the second annular axial projection is integrally connected to the first inner link face by a single material. the above No. 8A bicycle chain having the above characteristics has improved wear resistance, suppressed chain elongation, and improved drive efficiency compared to chains that are not integrally connected with a single material.

[0014] A ninth aspect of the present disclosure provides a bicycle chain, the plurality of inner link plates have inner link sliding surfaces that slide against outer peripheral surfaces of the pins, The first inner link plate has a first inner link sliding surface formed on the inner surface of the first inner link opening and the inner surface of the first annular axial protrusion, extending parallel to the first inner link central axis, and sliding against the first outer peripheral surface of the first pin, and the second inner link plate has a second inner link sliding surface formed on the inner surface of the third inner link opening and the inner surface of the third annular axial protrusion, extending parallel to the third inner link central axis, and sliding against the first outer peripheral surface of the first pin. According to the bicycle chain of the ninth feature, the wear resistance of the bicycle chain having the first inner link sliding surface and the second inner link sliding surface is improved, chain elongation is suppressed, and driving efficiency is improved.

[0015] The present disclosure No. 10 In the bicycle chain according to the above feature, the first inner link sliding surface has a first axial sliding surface length of 0.5 mm or more and 3.5 mm or less in the axial direction of the first inner link, and the second inner link sliding surface has a second axial sliding surface length of 0.5 mm or more and 3.5 mm or less in the axial direction of the second inner link. the above No. 10 A bicycle chain according to the above feature has improved wear resistance, reduced chain elongation, and improved drive efficiency compared to chains with first axial sliding surface lengths and second axial sliding surface lengths outside the above ranges. Furthermore, compared to chains with first axial sliding surface lengths and second axial sliding surface lengths outside the above ranges, it achieves smoother engagement between the inner link plates of the bicycle chain and the sprocket teeth of the bicycle sprocket, and smoother gear shifting between adjacent bicycle sprockets.

[0016] The present disclosure No. 11 In the bicycle chain according to the above feature, the first inner link sliding surface has a first inner link sliding surface hardness of 200 HV or more and 2500 HV or less, and the second inner link sliding surface has a second inner link sliding surface hardness of 200 HV or more and 2500 HV or less. the above No. 11 According to the bicycle chain having the above characteristics, the wear resistance is further improved, chain elongation is suppressed, and drive efficiency is improved compared to chains in which the first inner link sliding surface hardness and the second inner link sliding surface hardness are outside the above range.

[0017] The present disclosure 12th In a bicycle chain according to the above feature, the first inner link sliding surface has a first axial sliding surface length defined in the first inner link axial direction, the second inner link sliding surface has a second axial sliding surface length defined in the second inner link axial direction, the first pin, when the bicycle chain is assembled, has a first pin central axis, a first pin axial end face, a second pin axial end face, and a first shaft extending between the first pin axial end face and the second pin axial end face in the first pin axial direction relative to the first pin central axis, the first pin axial length being defined between the first pin axial end face and the second pin axial end face in the first pin axial direction, the ratio of the first pin axial length to the first axial sliding surface length being between 2 and 7, and the ratio of the first pin axial length to the second axial sliding surface length being between 2 and 7. the above 12th According to the bicycle chain having the above features, the ratio of the first pin axial length to the first axial sliding surface length and the ratio of the first pin axial length to the second axial sliding surface length are outside the above ranges, and this results in improved wear resistance, suppressed chain elongation, and improved drive efficiency.

[0018] The present disclosure 13thIn the bicycle chain according to the above feature, the ratio of the first pin axial length to the first axial sliding surface length is 3.5 or more and 6 or less, and the ratio of the first pin axial length to the second axial sliding surface length is 3.5 or more and 6 or less. the above 13th According to the bicycle chain having the above features, the ratio of the first pin axial length to the first axial sliding surface length and the ratio of the first pin axial length to the second axial sliding surface length are outside the above ranges, and this results in improved wear resistance, suppressed chain elongation, and improved drive efficiency.

[0019] The present disclosure No. 14 In a bicycle chain according to the above feature, the first annular axial protruding portion has a first radial thickness defined in a radial direction relative to the central axis of the first inner link, the third annular axial protruding portion has a second radial thickness defined in a radial direction relative to the central axis of the third inner link, the first pin, when the bicycle chain is assembled, has a first pin central axis, a first pin axial end face, a second pin axial end face, and a first shaft extending between the first pin axial end face and the second pin axial end face in the first pin axial direction relative to the first pin central axis, a first pin axial length defined between the first pin axial end face and the second pin axial end face in the first pin axial direction, a ratio of the first pin axial length to the first radial thickness being equal to or greater than 6 and equal to 20, and a ratio of the first pin axial length to the second radial thickness being equal to or greater than 6 and equal to 20. the above No. 14 According to the bicycle chain having the above features, the ratio of the first pin axial length to the first radial thickness and the ratio of the first pin axial length to the first radial thickness are outside the above ranges, and this further improves wear resistance, suppresses chain elongation, and improves drive efficiency.

[0020] The present disclosure No. 15In the bicycle chain according to the above feature, the ratio of the first pin axial length to the first radial thickness is 8 or more and 15 or less, and the ratio of the first pin axial length to the second radial thickness is 8 or more and 15 or less. the above No. 15 According to the bicycle chain having the above features, the ratio of the first pin axial length to the first radial thickness and the ratio of the first pin axial length to the first radial thickness are outside the above ranges, and this further improves wear resistance, suppresses chain elongation, and improves drive efficiency.

[0021] The present disclosure No. 16 In a bicycle chain according to the above feature, when the bicycle chain is assembled, the first pin has a first pin central axis, a first pin axial end face, a second pin axial end face, and a first shaft extending between the first pin axial end face and the second pin axial end face in the circumferential direction of the first pin relative to the first pin central axis. the above No. 16 According to the bicycle chain having the above features, when assembled, the bicycle chain has a first pin central axis, a first pin axial end face, a second pin axial end face, and a first shaft extending between the first pin axial end face and the second pin axial end face in the first pin circumferential direction relative to the first pin central axis, which improves wear resistance, suppresses chain elongation, and improves drive efficiency.

[0022] The present disclosure No. 17 In the bicycle chain according to the above feature, a first anti-slip portion is formed around the entire axial end face of the first pin in the circumferential direction of the first pin, and a second anti-slip portion is formed around the entire axial end face of the second pin in the circumferential direction of the first pin. the above No. 17 According to the bicycle chain having the above features, the bicycle chain has improved wear resistance, suppressed chain elongation, and improved drive efficiency. The first and second retaining portions improve the strength of the bicycle chain.

[0023] The present disclosure 18th In the bicycle chain according to the above feature, the first anti-slip portion is formed around the entire axial end face of the first pin by a crimping process, and the second anti-slip portion is formed around the entire axial end face of the second pin by a crimping process. the above 18th According to the bicycle chain having the features described above, the bicycle chain has first and second retaining portions formed by the crimping process, which improves wear resistance, suppresses chain elongation, and improves drive efficiency. Because the first and second retaining portions are formed by the crimping process, the bicycle chain is highly efficient in manufacturing.

[0024] The present disclosure No. 19 In a bicycle chain according to the above feature, the first pin axial end face is located on the same plane as the second outer link surface or between the first outer link surface and the second outer link surface in the first pin axial direction relative to the first pin central axis, and the second pin axial end face is located on the same plane as the fourth outer link surface or between the third outer link surface and the fourth outer link surface in the first pin axial direction relative to the first pin central axis. the above No. 19 According to the bicycle chain of feature 1, the first pin axial end face and the second pin axial end face are located in the aforementioned positions, which improves the wear resistance of the bicycle chain, suppresses chain elongation, and improves drive efficiency.Furthermore, according to the bicycle chain of feature 20, the first pin axial end face and the second pin axial end face are located in the aforementioned positions, which allows for smooth gear shifting of the bicycle chain between adjacent bicycle sprockets, and allows for an increase in the number of rear bicycle sprockets by reducing the size of the bicycle chain in the pin axial direction.

[0025] The present disclosure 20th In the bicycle chain according to the feature of (1), the first pin is inserted into the first outer link opening and the third outer link opening in a press-fit state when the bicycle chain is in an assembled state. the above 20th According to the bicycle chain of the above feature, when the bicycle chain is assembled, the first pin is inserted in a press-fit state into the first outer link opening and the third outer link opening, improving the wear resistance of the bicycle chain, suppressing chain elongation, and improving drive efficiency. Because the first pin is inserted in a press-fit state into the first outer link opening and the third outer link opening, the strength of the bicycle chain is improved.

[0026] The present disclosure No. 21 In a bicycle chain according to the above feature, the first inner link plate has a first inner link recess formed from the first inner link surface toward the second inner link surface at least in the first inner link intermediate portion, and the first inner link plate has a second inner link recess formed from the third inner link surface toward the fourth inner link surface at least in the second inner link intermediate portion. the above No. 21 According to the bicycle chain having the above features, the bicycle chain has first and second inner link recesses, which improves wear resistance, suppresses chain elongation, and improves drive efficiency. Because the bicycle chain has first and second inner link recesses, the sprocket teeth of the bicycle sprocket and the inner link plates can smoothly engage with each other, even if the bicycle chain is made smaller in size in the pin axis direction.

[0027] The present disclosure No. 22 In the bicycle chain according to the feature of the present invention, the second inner link surface of the intermediate portion of the first inner link is flat, and the fourth inner link surface of the intermediate portion of the second inner link is flat. the above No. 22According to the bicycle chain having the above features, the second inner link surface at the intermediate portion of the first inner link is flat, and the fourth inner link surface at the intermediate portion of the second inner link is flat. This improves the wear resistance of the bicycle chain, suppresses chain elongation, and improves drive efficiency. Because the second inner link surface at the intermediate portion of the first inner link is flat, and the fourth inner link surface at the intermediate portion of the second inner link is flat, the bicycle chain can be made smaller in the pin axis direction, allowing for an increase in the number of bicycle rear sprockets.

[0028] The present disclosure No. 23 In a bicycle chain according to the above feature, a first inner link opening recess is formed around the first inner link opening on the second inner link surface, a second inner link opening recess is formed around the second inner link opening on the second inner link surface, a third inner link opening recess is formed around the third inner link opening on the fourth inner link surface, and a fourth inner link opening recess is formed around the fourth inner link opening on the fourth inner link surface. the above No. 23 According to the bicycle chain of the above features, the first inner link opening recess, the second inner link opening recess, the third inner link opening recess, and the fourth inner link opening recess are formed in the bicycle chain, which improves wear resistance, suppresses chain elongation, and improves drive efficiency.The first inner link opening recess, the second inner link opening recess, the third inner link opening recess, and the fourth inner link opening recess suppress excessive interference between the inner link plates and the outer link plates.

[0029] The present disclosure No. 24In a bicycle chain according to the above feature, the first inner link end portion of the first inner link plate has a first inner link sprocket tooth retaining portion configured to retain a sprocket tooth when the bicycle chain engages with a sprocket tooth on a bicycle sprocket, the second inner link end portion of the first inner link plate has a second inner link sprocket tooth retaining portion configured to retain a sprocket tooth when the bicycle chain engages with a sprocket tooth on a bicycle sprocket, a first inner link chamfer portion is formed on the first inner link face of the first inner link sprocket tooth retaining portion, and a second inner link chamfer portion is formed on the first inner link face of the second inner link sprocket tooth retaining portion. the above No. 24 According to the bicycle chain of the above features, the bicycle chain has a first inner link sprocket tooth retaining portion and a second inner link sprocket tooth retaining portion, and is formed with a first inner link chamfered portion and a second inner link chamfered portion, which improves wear resistance, suppresses chain elongation, and improves drive efficiency.The first inner link chamfered portion and the second inner link chamfered portion make it easier for the bicycle chain to engage with the sprocket teeth of the bicycle sprocket, with the sprocket teeth of the bicycle sprocket retained by the first inner link sprocket tooth retaining portion and the second inner link sprocket chamfered portion.

[0030] The present disclosure No. 25In a bicycle chain according to the above feature, the third inner link end portion of the second inner link plate has a third inner link sprocket tooth retaining portion configured to retain a sprocket tooth when the bicycle chain engages with a sprocket tooth on a bicycle sprocket, the fourth inner link end portion of the second inner link plate has a fourth inner link sprocket tooth retaining portion configured to retain a sprocket tooth when the bicycle chain engages with a sprocket tooth on a bicycle sprocket, a third inner link chamfer portion is formed on the third inner link face of the third inner link sprocket tooth retaining portion, and a fourth inner link chamfer portion is formed on the third inner link face of the fourth inner link sprocket tooth retaining portion. the above No. 25 According to the bicycle chain of the above features, the bicycle chain has a third inner link sprocket tooth retaining portion and a fourth inner link sprocket tooth retaining portion, and the third inner link chamfered portion and the fourth inner link chamfered portion are formed, which improves wear resistance, suppresses chain elongation, and improves drive efficiency.The third inner link chamfered portion and the fourth inner link chamfered portion make it easier for the bicycle chain to engage with the sprocket teeth of the bicycle sprocket, with the sprocket teeth of the bicycle sprocket retained by the third inner link sprocket tooth retaining portion and the fourth inner link sprocket tooth retaining portion.

[0031] The present disclosure No. 26 In the bicycle chain according to the above feature, the plurality of pins may have pin through holes that pass through in the longitudinal direction. the above No. 26 According to the bicycle chain having the above features, the bicycle chain has improved wear resistance, reduced chain elongation, and improved drive efficiency. By forming the pin through holes, the bicycle chain is made lighter. [Effects of the Invention]

[0032] The bicycle chain of the present disclosure has excellent wear resistance, reduces chain elongation, and improves drive efficiency. [Brief explanation of the drawings]

[0033] [Figure 1] A schematic diagram of a bicycle, seen from above. [Figure 2] 1 is a perspective view of a bicycle chain according to a first embodiment. [Figure 3] FIG. 1 is an exploded explanatory view of a bicycle chain according to a first embodiment. [Figure 4] FIG. 4 is an enlarged view of the first (second) inner link plate in FIG. 3. [Figure 5] FIG. 4 is an enlarged view of the first (second) outer link plate in FIG. 3. [Figure 6] An enlarged view of the first (second) pin in Figure 3. [Figure 7] FIG. 2 is a longitudinal cross-sectional view of the bicycle chain according to the first embodiment before crimping. [Figure 8] Enlarged view of part of Figure 7 after crimping. [Figure 9] An explanatory diagram of the dimensions of the sliding surfaces of the first pin and the first (second) inner link plate. [Figure 10] An explanatory diagram of the dimensions of the sliding surface between the second pin and the first (second) inner link plate. DETAILED DESCRIPTION OF THE INVENTION

[0034] Referring to FIG. 1, a bicycle to which a bicycle chain is applied will be described. FIG. 1 shows a schematic diagram of a drivetrain 101 as viewed from above a bicycle including the drivetrain 101. The drive train 101 is of the chain drive type. The drive train 101 includes a bicycle crank assembly 102, a bicycle sprocket (hereinafter referred to as the "sprocket"), and a bicycle chain 100. The sprocket has sprocket teeth that the bicycle chain 100 engages. The sprockets include a front sprocket 103 and a rear sprocket 104. The bicycle crank assembly 102 includes a crankshaft 105 rotatably supported on the bicycle frame, and a pair of crank arms 106 provided at both ends of the crankshaft 105 . A pedal is rotatably attached to the tip of each crank arm 106.

[0035] The front sprocket 103 is provided on the crankshaft 105 so as to rotate integrally with the crankshaft 105 . The rear sprocket 104 is mounted on the hub of the rear wheel. The bicycle chain 100 is wound around a front sprocket 103 and a rear sprocket 104 . The driving force applied to the pedals by a user riding the bicycle is transmitted to the rear wheel via crank arm 106, crankshaft 105, front sprocket 103, bicycle chain 100, and rear sprocket 104.

[0036] 2 to 9, the detailed configuration of a bicycle chain 100 according to one embodiment of the present invention will be described. In this embodiment, each inner link plate, outer link plate, and pin is symmetrical in the longitudinal direction of bicycle chain 100, while first inner link plate 110 and second inner link plate 120, and first outer link plate 130 and second outer link plate 140 are symmetrical in the width direction of bicycle chain 100. Therefore, components not explicitly shown in the figures are described using corresponding reference numerals in the text. However, in the present invention, each inner link plate, outer link plate, and pin may have an asymmetrical shape in the longitudinal direction of bicycle chain 100, or in the width direction of bicycle chain 100. As shown in FIG. 2, the bicycle chain 100 includes a plurality of inner link plates, a plurality of outer link plates, and a plurality of pins. The plurality of inner link plates includes a first inner link plate 110 and a second inner link plate 120 . The plurality of outer link plates includes a first outer link plate 130 and a second outer link plate 140 , and the plurality of pins includes a first pin 150 .

[0037] As shown in Figures 3, 4, 7, 8, etc., the first inner link plate 110 includes a first inner link end portion 111 including a first inner link opening 111A having a first inner link central axis A1 and a first annular axial protrusion 111B surrounding the first inner link opening 111A in the circumferential direction with respect to the first inner link central axis A1, a second inner link opening 112A having a second inner link central axis A2 extending parallel to the first inner link central axis A1, and a second inner link center The second inner link end portion 112 includes a second annular axial protrusion 112B that surrounds the second inner link opening 112A circumferentially with respect to the central axis A2, a first inner link intermediate portion 113 that connects the first inner link end portion 111 and the second inner link end portion 112, a first inner link surface 114, and a second inner link surface 115 that is arranged on the opposite side of the first inner link surface 114 in the first inner link axial direction DA with respect to the first inner link central axis A1. The first annular axial protrusion 111B has a first proximal end 111BN connected to the first inner link surface 114 and a first distal end 111BF, and the second annular axial protrusion 112B has a second proximal end 112BN connected to the first inner link surface 114 and a second distal end 112BF.

[0038] Similar to the first inner link plate 110, the second inner link plate 120 includes a third inner link end portion 121 including a third inner link opening 121A having a third inner link central axis A3 and a third annular axial protruding portion 121B circumferentially surrounding the third inner link opening 121A with respect to the third inner link central axis A3; The bicycle chain 100 includes a fourth inner link end portion 122 including a fourth inner link opening 122A having a fourth inner link center axis A4 extending parallel to the third inner link center axis A3, and a fourth annular axial protrusion 124B circumferentially surrounding the fourth inner link opening 122A with respect to the fourth inner link center axis A4; a second inner link intermediate portion 123 connecting the third inner link end portion 121 and the fourth inner link end portion 122; a third inner link surface 124 configured to face the first inner link surface 114 of the first inner link plate 110 in the first inner link axial direction DA when the bicycle chain 100 is in an assembled state; and a fourth inner link surface 125 arranged on the opposite side of the third inner link surface 124 in the second inner link axial direction DB with respect to the third inner link center axis A3. The third annular axial protrusion 121B has a third proximal end 121BN connected to the third inner link surface 124, and a third distal end 121BF positioned opposite the first distal end 111BF of the first annular axial protrusion 111B when the bicycle chain is in an assembled state. The fourth annular axial protrusion 122B has a fourth proximal end 122BN connected to the third inner link surface 124, and a fourth distal end 122BF positioned opposite the second distal end 112BF of the second annular axial protrusion 112B when the bicycle chain 100 is in an assembled state.

[0039] As shown in Figures 3, 5, 7, 8, etc., the first outer link plate 130 is configured to be adjacent to the first inner link plate 110 without any other inner link plate or other outer link plate in between when the bicycle chain 100 is assembled. The first outer link plate 130 includes a first outer link end portion 131 including a first outer link opening 131A having a first outer link central axis B1, a second outer link end portion 132 including a second outer link opening 132A having a second outer link central axis B2 extending parallel to the first outer link central axis B1, a first outer link intermediate portion 133 connecting the first outer link end portion 131 and the second outer link end portion 132, a first outer link surface 134, and a second outer link surface 135 arranged on the opposite side of the first outer link surface 134 in the first outer link axial direction DE relative to the first outer link central axis B1.

[0040] Like the first outer link plate 130, the second outer link plate 140 is configured to be adjacent to the second inner link plate 120 without any other inner link plate or other outer link plate in between when the bicycle chain 100 is assembled. The second outer link plate 140 includes a third outer link end portion 141 including a third outer link opening 141A having a third outer link central axis B3, a fourth outer link end portion 142 including a fourth outer link opening 142A having a fourth outer link central axis B4 extending parallel to the third outer link central axis B3, a second outer link intermediate portion 143 connecting the third outer link end portion 141 and the fourth outer link end portion 142, a third outer link surface 144 configured to face the first outer link surface 134 of the first outer link plate 130 in the first outer link axial direction DE when the bicycle chain 100 is in an assembled state, and a fourth outer link surface 145 arranged on the opposite side of the third outer link surface 144 in the second outer link axial direction DF relative to the third outer link central axis B3.

[0041] As shown in Figures 3, 6 to 8, etc., first pin 150 is configured to be inserted through first outer link opening 131A, third outer link opening 141A, first inner link opening 111A, and third inner link opening 121A when bicycle chain 100 is in an assembled state, and has a first outer surface 151 that slides against first annular axial protrusion 111B and third annular axial protrusion 121B when bicycle chain 100 is in use. The multiple pins include a second pin 160, which is configured to be inserted through the second outer link opening 132A, the fourth outer link opening 142A, the second inner link opening 112A, and the fourth inner link opening 122A when the bicycle chain 100 is in an assembled state, and has a second outer surface 161 that slides against the second annular axial protrusion 112B and the fourth annular axial protrusion 122B when the bicycle chain 100 is in use. The pins 150 and 160 have outer peripheral surfaces 151 and 161, which are partially or entirely formed with: Contains one of Ti carbide, Nb carbide, Cr nitride, and Ti nitride Has a pin hardened layer HL. The multiple pins 150, 160 have pin through-holes 152, 162 passing through in the longitudinal direction. The pin hardened layer HL preferably has a sliding surface hardness of 1000 HV or more and 3500 HV or less.

[0042] The first proximal end 111BN of the first annular axial protrusion 111B is integrally connected to the first inner link surface 114 with a single material, and the second proximal end 121BN of the second annular axial protrusion 121B is integrally connected to the first inner link surface 114 with a single material. The first inner link plate 110 has a first inner link sliding surface 111C formed on the inner surface of the first inner link opening 111A and the inner surface of the first annular axial protrusion 111B, extending parallel to the first inner link central axis A1, and sliding against the first outer surface 151 of the first pin 150. The second inner link plate 120 has a second inner link sliding surface 112C formed on the inner surface of the third inner link opening 121A and the inner surface of the third annular axial protrusion 121B, extending parallel to the third inner link central axis A3, and sliding against the first outer surface 151 of the first pin 150.

[0043] It is preferable that the multiple inner link plates 110, 120 have inner link sliding surfaces 111C, 121C, 112C, 122C that slide against the outer peripheral surfaces 151, 161 of the pins 150, 160, and that the sliding surface hardness of the pin hardened layer HL is greater than the surface hardness of the inner link sliding surfaces 111C, 121C, 112C, 122C. A link hardening layer RH containing any one of Cr carbide, Ti carbide, V carbide, Nb carbide, Cr nitride, Ti nitride, V nitride, and Nb nitride may be provided on a part or all of the inner link sliding surfaces 111C, 121C, 112C, and 122C. The surface roughness of the pin hardened layer HL is preferably smaller than the surface roughness of the inner link sliding surfaces 111C, 121C, 112C, and 122C. The plurality of pins include connecting pins for connecting the chain in an endless manner, and the surface condition of the connecting pins may be formed differently from the other pins 150 and 160 .

[0044] As shown in FIG. 9, the first inner link sliding surface 111C preferably has a first axial sliding surface length LL1 of 0.5 mm or more and 3.5 mm or less in the first inner link axial direction DA. The second inner link sliding surface 121C preferably has a second axial sliding surface length LL2 of 0.5 mm or more and 3.5 mm or less in the second inner link axial direction DB. The first inner link sliding surface 111C preferably has a first inner link sliding surface hardness of 200 HV or more and 2500 HV or less. The second inner link sliding surface 121C preferably has a second inner link sliding surface hardness of 200 HV or more and 2500 HV or less.

[0045] As shown in Figure 9, the first inner link sliding surface 111C has a first axial sliding surface length LL1 defined in the first inner link axial direction DA, and the second inner link sliding surface 121C has a second axial sliding surface length LL2 defined in the second inner link axial direction DB. When the bicycle chain 100 is assembled, the first pin 150 has a first pin central axis P1, a first pin axial end face 153, a second pin axial end face 154, and a first shaft 155 extending between the first pin axial end face 153 and the second pin axial end face 154 in the first pin axial direction DP relative to the first pin central axis P1. The first pin axial length LP1 is defined in the first pin axial direction DP between the first pin axial end face 153 and the second pin axial end face 154, and the ratio of the first pin axial length LP1 to the first axial sliding surface length LL1 is preferably 2 or more and 7 or less, and more preferably 3.5 or more and 6 or less. The ratio of the first pin axial length LP1 to the second axial sliding surface length LL2 is preferably 2 or more and 7 or less, and more preferably 3.5 or more and 6 or less. As shown in FIG. 10, the third inner link sliding surface 112C has a third axial sliding surface length LL3 defined in the third inner link axial direction DC, and the fourth inner link sliding surface 122C has a fourth axial sliding surface length LL4 defined in the fourth inner link axial direction DD. When the bicycle chain 100 is assembled, the second pin 160 has a second pin central axis P2, a third pin axial end face 163, a fourth pin axial end face 164, and a second shaft 165 extending between the third pin axial end face 163 and the fourth pin axial end face 164 in the second pin axial direction DP2 relative to the second pin central axis P2. The second pin axial length LP2 is defined in the second pin axial direction DP2 between the third pin axial end face 163 and the fourth pin axial end face 164, and the ratio of the second pin axial length LP2 to the third axial sliding surface length LL3 is preferably 2 or more and 7 or less, and more preferably 3.5 or more and 6 or less. The ratio of the second pin axial length LP2 to the fourth axial sliding surface length LL4 is preferably 2 or more and 7 or less, and more preferably 3.5 or more and 6 or less.

[0046] As shown in FIG. 9, the first annular axial protrusion 111B has a first radial thickness WL1 defined in a radial direction relative to the first inner link central axis A1, and the third annular axial protrusion 121B has a second radial thickness WL2 defined in a radial direction relative to the third inner link central axis A3. The first pin axial length LP1 is defined in the first pin axial direction between the first pin axial end face 153 and the second pin axial end face 154, and the ratio of the first pin axial length LP1 to the first radial thickness WL1 is preferably 6 or more and 20 or less, and more preferably 8 or more and 15 or less. The ratio of the first pin axial length LP1 to the second radial thickness WL2 is preferably 6 or more and 20 or less, and more preferably 8 or more and 15 or less. As shown in FIG. 10, the second annular axial protrusion 112B has a third radial thickness WL3 defined in the radial direction relative to the second inner link central axis A2, and similar to the third annular axial protrusion 121B, the fourth annular axial protrusion 122B has a fourth radial thickness WL4 defined in the radial direction relative to the fourth inner link central axis A4. The second pin axial length LP2 is defined in the second pin axial direction DP2 between the third pin axial end face 163 and the fourth pin axial end face 164, and the ratio of the second pin axial length LP2 to the third radial thickness WL3 is preferably 6 or more and 20 or less, and more preferably 8 or more and 15 or less. The ratio of the second pin axial length LP2 to the fourth radial thickness WL4 is preferably 6 or more and 20 or less, and more preferably 8 or more and 15 or less.

[0047] As shown in Figure 8, a first retaining portion 156 is formed around the entire circumference of the axial end face 153 of the first pin in the circumferential direction of the first pin, and a second retaining portion 157 is formed around the entire circumference of the axial end face 154 of the second pin in the circumferential direction of the first pin. The first retaining portion 156 is formed on the entire periphery of the first pin axial end face 153 by a crimping process, and the second retaining portion 157 is formed on the entire periphery of the second pin axial end face 154 by a crimping process.

[0048] The first pin axial end face 153 is located on the same plane as the second outer link surface 135 or between the first outer link surface 134 and the second outer link surface 135 in the first pin axial direction DP relative to the first pin central axis P1, and the second pin axial end face 154 is located on the same plane as the fourth outer link surface 145 or, as shown in Figure 8, between the third outer link surface 144 and the fourth outer link surface 145 in the first pin axial direction DP relative to the first pin central axis P1. Preferably, first pin 150 is press-fit through first outer link opening 131A and third outer link opening 141A when bicycle chain 100 is assembled. Preferably, second pin 160 is press-fit through second outer link opening 132A and fourth outer link opening 142A when bicycle chain 100 is assembled.

[0049] The first inner link plate 110 has a first inner link recess 116 formed at least in the first inner link intermediate portion 113 from the first inner link surface 114 toward the second inner link surface 115 . The second inner link plate 120 has a second inner link recess 126 formed at least in the second inner link intermediate portion 123 from the third inner link surface 124 toward the fourth inner link surface 125 . The second inner link surface 115 of the first inner link intermediate portion 113 is flat, and the fourth inner link surface 125 of the second inner link intermediate portion 123 is flat. A first inner link opening recess 111D is formed around the first inner link opening 111A in the second inner link surface 115, and a second inner link opening recess 112D is formed around the second inner link opening 112A in the second inner link surface 115. A third inner link opening recess 121D is formed around the third inner link opening 121A in the fourth inner link surface 125, and a fourth inner link opening recess 122D is formed around the fourth inner link opening 122A in the fourth inner link surface 125.

[0050] First inner link end portion 111 of first inner link plate 110 has first inner link sprocket tooth retaining portion 111E configured to retain sprocket teeth when bicycle chain 100 engages with sprocket teeth of a bicycle sprocket. Second inner link end portion 112 of first inner link plate 110 has second inner link sprocket tooth retaining portion 112E configured to retain sprocket teeth when bicycle chain 100 engages with sprocket teeth of a bicycle sprocket. A first inner link chamfer portion 117 is formed on the first inner link surface 114 of the first inner link sprocket tooth retaining portion 111E, and a second inner link chamfer portion 118 is formed on the first inner link surface 114 of the second inner link sprocket tooth retaining portion 112E.

[0051] Third inner link end portion 121 of second inner link plate 120 has third inner link sprocket tooth retaining portion 121E configured to retain sprocket teeth when bicycle chain 100 engages with sprocket teeth of a bicycle sprocket. Fourth inner link end portion 122 of second inner link plate 120 has a fourth inner link sprocket tooth retaining portion 122E configured to retain a sprocket tooth when bicycle chain 100 engages with a sprocket tooth of a bicycle sprocket. A third inner link chamfer portion 127 is formed on the third inner link surface 124 of the third inner link sprocket tooth retaining portion 121E, and a fourth inner link chamfer portion 128 is formed on the third inner link surface 124 of the fourth inner link sprocket tooth retaining portion 122E.

[0052] The first outer link plate 130 and the second outer link plate 140 are connected by a first pin 150 and a second pin 160 . The first inner link plate 110 and the second inner link plate 120 are connected by a first pin 150 and a second pin 160 . The combined assembly of the first inner link plate 110 and the second inner link plate 120 is connected to the combined assembly of the first outer link plate 130 and the second outer link plate 140 so as to be rotatable about the central axis of the first pin 150 and the central axis of the second pin 160. The combined assembly of the first inner link plate 110 and the second inner link plate 120 and the combined assembly of the first outer link plate 130 and the second outer link plate 140 are arranged alternately and connected in the form of a loop.

[0053] The roller 170 is configured to be located between the first inner link surface 114 of the first inner link plate 120 and the third inner link surface 124 of the second inner link plate 120 when the bicycle chain 100 is in an assembled state. The roller 170 is disposed between the first inner link end portion 111 of the first inner link plate 110 and the third inner link end portion 121 of the second inner link plate 120 . The roller 170 has roller holes 171 through which the annular axial protrusions 111B, 112B, 121B, and 122B pass. The rollers 170 are rotatable relative to the annular axial protrusions 111B, 112B, 121B, and 122B, and when the bicycle chain 100 is mounted on the bicycle A, the rollers 170 come into contact with the sprocket teeth.

[0054] In the bicycle chain 100 of this embodiment, the outer surfaces 151, 161 of the pins 150, 160 are provided with at least the inner link sliding surfaces 111C, 121C, 112C, 122C of the inner link plates 110, 120. , Ti carbide, Nb carbide, Cr nitride, and Ti nitride. A hardened pin layer is formed. By forming a pin hardened layer on the surface of the pin using these materials, it is possible to increase the surface hardness compared to pin materials that are simply hardened by heat treatment, etc., and wear can be reduced. However, conversely, wear on the sliding surface increases, so it is desirable that the surface hardness be within a certain range.

[0055] When changing gears, a bicycle chain is shifted over multiple sprockets arranged side by side in the width direction, so it is used in a state where it is misaligned and bent in the width direction. Therefore, a certain clearance is provided between the sliding surface of the inner link and the outer peripheral surface of the pin, and sliding does not always occur under constant conditions; the sliding point is constantly changing, and the pressing force at the sliding point is not constant and frequently increases suddenly. In this case, the sliding area of the inner link (concavely curved) is less susceptible to elastic deformation and less able to absorb pressure and impact than the sliding area of the pin (convexly curved). Therefore, if the surface hardness is the same, the outer surface of the pin will experience greater wear and damage than the sliding surface of the inner link. Therefore, by providing a pin hardened layer on the outer peripheral surface of the pin that is harder than the surface of the sliding surface of the inner link, the wear resistance of the pin is improved, chain elongation is suppressed, and drive efficiency is improved. Furthermore, if a hardened link layer is also provided on the sliding surface of the inner link, the wear resistance of the sliding surface of the inner link is further improved, and chain elongation is suppressed. [Explanation of symbols]

[0056] 100 ··· Bicycle chain 101 Drivetrain 102 Bicycle crank assembly 103 Front sprocket 104 Rear sprocket 105 Crankshaft 106 Crank arm 110 First inner link plate 111 First inner link end 111A··· First inner link opening 111B First annular axial protrusion 111BN·· First proximal end 111BF First distal end 111C··· First inner link sliding surface 111D First inner link opening recess 111E First inner link sprocket tooth retaining portion 112 Third inner link end 112A··· Third inner link opening 112B··· Third annular axial protrusion 112BN·· Third proximal end 112BF·· Third distal end 112C··· Third inner link sliding surface 112D Third inner link opening recess 112E Third inner link sprocket tooth retaining portion 113 Middle part of first inner link 114 First inner link surface 115 Second inner link surface 116 First inner link recess 117 First inner link chamfer 118 ··· Chamfered portion of second inner link 120 Second inner link plate 121 Second inner link end 121A··· Second inner link opening 121B... Second annular axial protrusion 121BN·· Second proximal end 121BF·· Second distal end 121C··· Second inner link sliding surface 121D··· Second inner link opening recess 121E Second inner link sprocket tooth retaining portion 122 4th inner link end 122A··· 4th inner link opening 122B··· Fourth annular axial protrusion 122BN·· 4th proximal end 122BF·· 4th distal end 122C··· 4th inner link sliding surface 122D··· 4th inner link opening recess 122E··· 4th inner link sprocket tooth retaining portion 123 Second inner link middle part 124 Second inner link surface 125 4th inner link surface 126 Second inner link recess 127 Chamfered part of second inner link 128 ··· Chamfered part of the fourth inner link 130 First outer link plate 131 First outer link end 131A First outer link opening 132 Third outer link end 132A Third outer link opening 133 First outer link middle section 134 First outer link surface 135 Third outer link surface 140 Second outer link plate 141 Second outer link end 141A Second outer link opening 142 4th outer link end 142A··· 4th outer link opening 143 Second outer link middle section 144 Second outer link surface 145 4th outer link surface 150 ··· 1st pin 151 ... 1st outer peripheral surface 152 First pin through hole 153 Axial end face of first pin 154 Axial end face of second pin 155 First axis 156 First retaining part 157 Second retaining part 160 ··· 2nd pin 161 ... 2nd outer peripheral surface 162 Second pin through hole 163 Axial end face of third pin 164 Axial end face of fourth pin 165 ··· Second axis body 166 Third retaining part 167 4th retaining part 170 ··· Laura 171 Roller hole A1: Central axis of the first inner link A2: Central axis of second inner link A3: Central axis of third inner link A4: Central axis of the fourth inner link B1: Central axis of first outer link B2: Central axis of second outer link B3: Central axis of third outer link B4: Central axis of the fourth outer link P1 ... 1st pin center axis P2... 2nd pin center axis DA: First inner link axial direction DB: Axial direction of second inner link DC 3rd inner link axial direction DD: Axial direction of fourth inner link DE: Axial direction of first outer link DF: Axial direction of second outer link DP 1st pin axial direction DP2: Second pin axial direction LL1: Length of first axial sliding surface LL2: Second axial sliding surface length LL3: Length of third axial sliding surface LL4: Length of fourth axial sliding surface LP1: Length of the first pin in the axial direction LP2: Second pin axial length WL1: First radial thickness WL2: Second radial thickness WL3: Third radial thickness WL4: Fourth radial thickness

Claims

1. A bicycle chain comprising a plurality of inner link plates, a plurality of outer link plates, and a plurality of pins, the plurality of inner link plates include a first inner link plate and a second inner link plate, the plurality of outer link plates include a first outer link plate and a second outer link plate, the plurality of pins includes a first pin; The first inner link plate is a first inner link end portion including a first inner link opening having a first inner link central axis and a first annular axial protruding portion surrounding the first inner link opening in a 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 protruding portion surrounding the second inner link opening in a 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; a second inner link surface disposed on the opposite side to the first inner link surface in a first inner link axial direction relative to the first inner link central axis, the first annular axial projection has a first proximal end coupled to the first inner link surface and a first distal end; the second annular axial projection has a second proximal end coupled to the first inner link surface and a second distal end; The second inner link plate is a third inner link end portion including a third inner link opening having a third inner link central axis and a third annular axial protruding portion surrounding the third inner link opening in a circumferential direction with respect to the 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, and a fourth annular axial protruding portion surrounding the fourth inner link opening in a circumferential direction with respect to the fourth 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 when the bicycle chain is in an assembled state; a fourth inner link surface disposed on the opposite side to the third inner link surface in a second inner link axial direction relative to the third inner link central axis, the third annular axial projection has a third proximal end coupled to the third inner link surface and a third distal end positioned opposite the first distal end of the first annular axial projection in an assembled state of the bicycle chain; the fourth annular axial projection has a fourth proximal end coupled to the third inner link surface and a fourth distal end positioned opposite the second distal end of the second annular axial projection in an assembled state of the bicycle chain; the first outer link plate is configured to be adjacent to the first inner link plate without any other inner link plate or other outer link plate in between when the bicycle chain is assembled; The first outer link plate is 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; a second outer link surface disposed on the opposite side to the first outer link surface in a first outer link axial direction relative to the first outer link central axis, the second outer link plate is configured to be adjacent to the second inner link plate without any other inner link plate or other outer link plate in between when the bicycle chain is assembled; The second outer link plate is 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 axial direction of the first outer link when the bicycle chain is in an assembled state; a fourth outer link surface disposed on the opposite side of the third outer link surface in a second outer link axial direction relative to the third outer link central axis, the first pin is configured to be inserted through the first outer link opening, the third outer link opening, the first inner link opening, and the third inner link opening when the bicycle chain is in an assembled state, and has a first outer peripheral surface that slides against the first annular axial protrusion and the third annular axial protrusion when the bicycle chain is in use; A bicycle chain characterized in that the plurality of pins include those having a pin-hardened layer containing one of Ti carbide, Nb carbide, Cr nitride, and Ti nitride on part or all of their outer surfaces.

2. 2. The bicycle chain according to claim 1, wherein the pin hardened layer has a sliding surface hardness of 1000 HV to 3500 HV.

3. the plurality of inner link plates have inner link sliding surfaces that slide against outer peripheral surfaces of the pins, 3. The bicycle chain according to claim 1, wherein the sliding surface hardness of the pin hardened layer is greater than the surface hardness of the sliding surface of the inner link.

4. the plurality of inner link plates have inner link sliding surfaces that slide against outer peripheral surfaces of the pins, 4. The bicycle chain according to claim 1, wherein the inner link sliding surface has a hardened link layer containing one of Cr carbide, Ti carbide, V carbide, Nb carbide, Cr nitride, Ti nitride, V nitride, and Nb nitride on part or all of the inner link sliding surface.

5. the plurality of inner link plates have inner link sliding surfaces that slide against outer peripheral surfaces of the pins, 5. The bicycle chain according to claim 1, wherein the surface roughness of the pin hardened layer is less than the surface roughness of the sliding surface of the inner link.

6. The plurality of pins include connecting pins for connecting an endless chain, 6. A bicycle chain according to claim 1, wherein the surface condition of said connecting pin is formed differently from that of the other pins.

7. the plurality of pins includes a second pin; 7. The bicycle chain of claim 1, wherein the second pin is configured to be inserted through the second outer link opening, the fourth outer link opening, the second inner link opening, and the fourth inner link opening when the bicycle chain is assembled, and has a second outer surface that slides against the second annular axial protrusion and the fourth annular axial protrusion when the bicycle chain is in use.

8. a first proximal end of the first annular axial projection integrally connected to the first inner link face with a single material; 8. The bicycle chain of claim 1, wherein the second proximal end of the second annular axial projection is integrally connected to the first inner link face with a single piece of material.

9. The plurality of inner link plates have inner link sliding surfaces that slide against the outer peripheral surfaces of the pins, the inner link sliding surface includes a first inner link sliding surface and a second inner link sliding surface, the first inner link plate has a first inner link sliding surface that is formed on an inner peripheral surface of the first inner link opening and an inner peripheral surface of a first annular axial protrusion, that extends parallel to a central axis of the first inner link, and that slides against the first outer peripheral surface of the first pin; 9. A bicycle chain according to claim 1, wherein the second inner link plate has a second inner link sliding surface formed on the inner peripheral surface of the third inner link opening and the inner peripheral surface of the third annular axial protrusion, extending parallel to the central axis of the third inner link and sliding against the first outer peripheral surface of the first pin.

10. the first inner link sliding surface has a first axial sliding surface length of 0.5 mm or more and 3.5 mm or less in the axial direction of the first inner link, 10. The bicycle chain according to claim 9, wherein the sliding surface of the second inner link has a second axial sliding surface length of 0.5 mm or more and 3.5 mm or less in the axial direction of the second inner link.

11. the first inner link sliding surface has a first inner link sliding surface hardness of 200 HV or more and 2500 HV or less, 11. The bicycle chain according to claim 9, wherein the sliding surface of the second inner link has a hardness of 200 HV or more and 2500 HV or less.

12. the first inner link sliding surface has a first axial sliding surface length defined in the first inner link axial direction, the second inner link sliding surface has a second axial sliding surface length defined in the second inner link axial direction, When the bicycle chain is assembled, the first pin has a first pin central axis, a first pin axial end face, a second pin axial end face, and a first shaft extending between the first pin axial end face and the second pin axial end face in the first pin axial direction relative to the first pin central axis, a first pin axial length is defined between the first pin axial end face and the second pin axial end face in the first pin axial direction, a ratio of the axial length of the first pin to the axial sliding surface length is 2 or more and 7 or less, 12. A bicycle chain according to claim 9, wherein the ratio of the axial length of the first pin to the length of the second axial sliding surface is between 2 and 7.

13. a ratio of the axial length of the first pin to the axial sliding surface length is 3.5 or more and 6 or less, 13. The bicycle chain according to claim 12, wherein the ratio of the axial length of the first pin to the length of the second axial sliding surface is between 3.5 and 6.

14. the first annular axial protrusion has a first radial thickness defined in a radial direction relative to the first inner link central axis; the third annular axial protruding portion has a second radial thickness defined in a radial direction relative to the third inner link central axis; When the bicycle chain is assembled, the first pin has a first pin central axis, a first pin axial end face, a second pin axial end face, and a first shaft extending between the first pin axial end face and the second pin axial end face in the first pin axial direction relative to the first pin central axis, a first pin axial length is defined between the first pin axial end face and the second pin axial end face in the first pin axial direction, a ratio of the first pin axial length to the first radial thickness is equal to or greater than 6 and is equal to or less than 20; 14. A bicycle chain according to claim 1, wherein the ratio of the first pin axial length to the second radial thickness is equal to or greater than 6 and equal to or less than 20.

15. a ratio of the first pin axial length to the first radial thickness is equal to or greater than 8 and is equal to or less than 15, 15. The bicycle chain according to claim 14, wherein the ratio of the first pin axial length to the second radial thickness is greater than or equal to 8 and less than or equal to 15.

16. 12. A bicycle chain according to any one of claims 1 to 11, characterized in that, when the bicycle chain is assembled, the first pin has a first pin central axis, a first pin axial end face, a second pin axial end face, and a first shaft extending between the first pin axial end face and the second pin axial end face in the first pin circumferential direction relative to the first pin central axis.

17. a first retaining portion is formed around the entire periphery of an axial end face of the first pin in the circumferential direction of the first pin; 17. The bicycle chain according to claim 16, wherein a second retaining portion is formed around the entire periphery of the axial end face of the second pin in the circumferential direction of the first pin.

18. the first retaining portion is formed around the entire periphery of the axial end face of the first pin by a crimping process, 18. The bicycle chain according to claim 17, wherein the second retaining portion is formed around the entire periphery of the axial end face of the second pin by a crimping process.

19. the first pin axial end surface is located on the same plane as the second outer link surface or between the first outer link surface and the second outer link surface in the first pin axial direction relative to the first pin central axis, 19. A bicycle chain as recited in any one of claims 16 to 18, characterized in that the second pin axial end face is located on the same plane as the fourth outer link surface or between the third outer link surface and the fourth outer link surface in the first pin axial direction relative to the first pin central axis.

20. 20. A bicycle chain as recited in any one of claims 1 to 19, wherein the first pin is press-fitted into the first outer link opening and the third outer link opening when the bicycle chain is assembled.

21. the first inner link plate has a first inner link recess formed at least in the first inner link intermediate portion from the first inner link surface toward the second inner link surface, 21. A bicycle chain according to any one of claims 1 to 20, characterized in that the second inner link plate has a second inner link recess formed at least in the middle portion of the second inner link from the third inner link surface toward the fourth inner link surface.

22. the second inner link surface of the first inner link intermediate portion is flat, 22. A bicycle chain according to claim 1, wherein the surface of the fourth inner link at the intermediate portion of the second inner link is flat.

23. a first inner link opening recess is formed around the first inner link opening on the second inner link surface, a second inner link opening recess is formed around the second inner link opening on the second inner link surface, a third inner link opening recess is formed around the third inner link opening on the fourth inner link surface, 23. The bicycle chain according to claim 1, wherein a fourth inner link opening recess is formed around the fourth inner link opening on the fourth inner link surface.

24. the first inner link end portion of the first inner link plate has a first inner link sprocket tooth retaining portion configured to retain a sprocket tooth when the bicycle chain engages with a bicycle sprocket; the second inner link end portion of the first inner link plate has a second inner link sprocket tooth retaining portion configured to retain a sprocket tooth when the bicycle chain engages with a bicycle sprocket; a first inner link chamfer portion is formed on the first inner link surface of the first inner link sprocket tooth retaining portion, 24. A bicycle chain according to claim 1, wherein a second inner link chamfer is formed on the first inner link surface of the second inner link sprocket tooth retaining portion.

25. the third inner link end portion of the second inner link plate has a third inner link sprocket tooth retaining portion configured to retain a sprocket tooth when the bicycle chain engages with a bicycle sprocket; the fourth inner link end portion of the second inner link plate has a fourth inner link sprocket tooth retaining portion configured to retain a sprocket tooth when the bicycle chain engages a sprocket tooth on a bicycle sprocket; a third inner link chamfer portion is formed on the third inner link surface of the third inner link sprocket tooth retaining portion, 25. A bicycle chain according to any one of claims 1 to 24, wherein a fourth inner link chamfer is formed on the third inner link surface of the fourth inner link sprocket tooth retaining portion.

26. 26. A bicycle chain according to any one of claims 1 to 25, wherein the plurality of pins includes a pin having a pin through-hole passing through in the longitudinal direction.

Images