HALF-LINK CHAIN ​​FOR A HUMAN-POWERED VEHICLE

Abstract

Providing a half-link chain capable of improving the holding force on a sprocket tooth. A half-link chain 1 includes a first chain link 31, a second chain link 33, a bushing 35, a first pin 37, and a second pin 39. A tooth engagement slot 81 has an axially narrow portion 83 and an axially wide portion 85. A first longitudinal slot length LX1 of the axially narrow portion 83 is greater than twice a second longitudinal slot length LX2 of the axially wide portion 85. The axially narrow portion 83 is configured to receive a sprocket tooth S of a sprocket during operation of the half-link chain 1.

Description

The present invention relates to a half link chain for a human-powered vehicle.A bicycle chain is trained around a front sprocket and a rear sprocket. The bicycle chains include normal chains and half link chains. In a normal chain, one chain link is composed of two kinds of chain links. The two types of links are, for example, an outer link and an inner link.The half link chain consists of one type of chain link. In a half link chain, the length of a chain pitch is smaller than in a normal chain. For this reason, the length of the half link chain can be easily adjusted as compared with the normal chain. An example of such a half-link chain is disclosed in EP 303 21 39 A1.In the half link chain of EP 303 21 39 A1, a sleeve is press-fitted into a hole portion of an inner link portion of each of a pair of chain links. A pin is disposed in an inner circumferential portion of the sleeve. A roller is disposed on an outer circumferential surface of the sleeve. Each of the two end portions of the pin is mounted to a hole portion of an outer link portion of a corresponding one of the pair of adjacent chain links.A conventional half link chain has a pair of links. The pair of chain links includes a first chain link and a second chain link arranged to face the first chain link. A sprocket tooth of a sprocket engages a tooth engaging slot. The tooth engagement slot is provided between a first link portion and a second link portion between a pair of rollers adjacent in the longitudinal direction.More specifically, the first link includes a first outer link portion and a first inner link portion. The second link includes a second outer link portion disposed to face the first outer link portion and a second inner link portion disposed to face the first inner link portion.The tooth engaging slot has an axially narrow portion and an axially wide portion. The axially narrow portion is provided between the first inner link portion of the first link and the second inner link portion of the second link. The axially wide portion is provided between the first outer link portion of the first link and the second outer link portion of the second link.The axially narrow portion has a first longitudinal slot length defined in a longitudinal direction of the half link chain. The axially wide portion has a second longitudinal slot length defined in the longitudinal direction of the half link chain. The first longitudinal slot length and the second longitudinal slot length are substantially identical.In this configuration, the sprocket tooth of the sprocket is disposed in the axially narrow portion and the axially wide portion. In this case, a portion of the sprocket tooth disposed in the axially wide portion is not substantially supported by the half link chain, so that a holding force on the sprocket tooth of the sprocket may be reduced.An object of the present invention is to provide a half link chain that can improve a holding force on a sprocket tooth.According to a first aspect of the present invention, a half link chain for a human-powered vehicle includes a first link, a second link, a sleeve, a first pin, and a second pin. The first link includes a first outer link portion and a first inner link portion. The first outer link portion has a first outer link opening with a first outer link central axis. The first inner link portion has a first inner link opening having a first inner link central axis. The first outer member central axis and the first inner member central axis define an axial direction. The first link further includes a first axially outward facing surface with respect to the axial direction and a first axially inward facing surface opposite the first axially outward facing surface with respect to the axial direction.The second link includes a second outer link portion and a second inner link portion. The second outer link portion has a second outer link opening with a second outer link central axis. The second inner link portion has a second inner link opening having a second inner link central axis. The second link further includes a second axially outward facing surface and a second axially inward facing surface opposite to the second axially outward facing surface with respect to the axial direction. The second axially inward facing surface is configured to axially face the first axially inward facing surface in the axial direction in an assembled state of the half link chain.The sleeve is configured to be inserted into the first inner link opening and the second inner link opening in the assembled state of the half link chain. The sleeve has a sleeve inner surface of the sleeve defining a sleeve cavity. The first pin is configured to be inserted into the first outer link opening of the first chain link and into the second outer link opening of the second chain link in the assembled state of the half link chain. The second pin is configured to be inserted into the first inner link opening of the first link, the second inner link opening of the second link, and the sleeve cavity of the sleeve when assembled. The second pin is configured to slide on the sleeve inner surface of the sleeve in the assembled state.In the assembled state of the half link chain, the second outer link center axis is configured to be coaxial with the first outer link center axis. In the assembled state of the half link chain, the second inner link center axis is configured to be coaxial with the first inner link center axis. The first outer member portion and the first inner member portion are at least partially offset from each other in the axial direction, such that the first outer member opening and the first inner member opening are offset from each other in the axial direction. The second outer member portion and the second inner member portion are at least partially offset from each other in the axial direction, such that the second outer member opening and the second inner member opening are offset from each other in the axial direction. The sleeve has a first sleeve end and a second sleeve end which, in the assembled state, is opposite the first sleeve end with respect to the axial direction. In the assembled state, the first sleeve end is configured to be disposed in the first inner link opening of the first link. In the assembled state, the second sleeve end is configured to be disposed in the second inner link opening of the second chain link.In the assembled state, a tooth engaging slot is formed between the first link and the second link with respect to the axial direction. The tooth engaging slot has an axially narrow portion and an axially wide portion. The axially narrow portion has a first longitudinal slot length defined in a longitudinal direction of the half link chain. The axially wide portion has a second longitudinal slot length defined in the longitudinal direction of the half link chain. One of the first longitudinal slot length and the second longitudinal slot length is greater than twice the other of the first longitudinal slot length of the axially narrow portion and the second longitudinal slot length of the axially wide portion. A corresponding one of the axially narrow portion and the axially wide portion with respect to the one of the first longitudinal slot length and the second longitudinal slot length is configured to receive a sprocket tooth of a sprocket of the half link chain during operation.In the half link chain according to the first aspect, the tooth engagement slot has the axially narrow portion and the axially wide portion. One of the first longitudinal slot length and the second longitudinal slot length is greater than twice the other of the first longitudinal slot length and the second longitudinal slot length. In this configuration, in a case where the first longitudinal slot length of the axially narrow portion is greater than twice the second longitudinal slot length of the axially wide portion, during operation of the half link chain, the axially narrow portion receives all or most of the sprocket tooth of the sprocket. In a case where the second longitudinal slot length of the axially wide portion is greater than twice the first longitudinal slot length of the axially narrow portion, during operation of the half link chain, the axially wide portion receives all or most of the sprocket tooth of the sprocket. In this way, during operation of the half link chain, a slot having a longer longitudinal slot length, for example, the axially narrow portion or the axially wide portion, supports the sprocket tooth of the sprocket, so that the holding force of the half link chain on the sprocket tooth can be improved. Further, with this configuration, since the first link and the second link are separate bodies, it is possible to cope with different frame dimensions. In addition, the provision of the sleeve can improve the strength of the half link chain.According to a second aspect of the present invention, in the half link chain according to the first aspect, the half link chain is configured as follows. One of the first longitudinal slit length of the axially narrow portion and the second longitudinal slit length of the axially wide portion is greater than three times the other of the first longitudinal slit length of the axially narrow portion and the second longitudinal slit length of the axially wide portion. In the half link chain according to the second aspect, in a case where the first longitudinal slot length of the axially narrow portion is greater than three times the second longitudinal slot length of the axially wide portion, during operation of the half link chain, the axially narrow portion takes up all or most of the sprocket tooth of the sprocket. In a case where the second longitudinal slot length of the axially wide portion is greater than three times the first longitudinal slot length of the axially narrow portion, because during operation of the half link chain, the axially wide portion receives all or most of the sprocket tooth of the sprocket. In this way, a slot having a longer longitudinal slot length, for example, the axially narrow portion or the axially wide portion, receives the sprocket tooth of the sprocket during operation of the half link chain, so that the holding force of the half link chain on the sprocket tooth can be improved.According to a third aspect of the present invention, in the half link chain according to the first or second aspect, the half link chain is formed as follows. The first longitudinal slot length of the axially narrow portion is greater than twice the second longitudinal slot length of the axially wide portion. According to the half link chain of the third aspect, during the operation of the half link chain, the axially narrow portion receives all or most of the sprocket tooth of the sprocket. With this configuration, the holding force of the half link chain on the sprocket tooth can be improved. In addition, during the operation of the half link chain, the axially narrow portion receives all or most of the sprocket tooth of the sprocket, so that the holding force of the half link chain on the sprocket tooth having a small thickness can be improved.According to a fourth aspect of the present invention, in the half link chain according to the third aspect, the half link chain is formed as follows. The first longitudinal slot length of the axially narrow portion is greater than three times the second longitudinal slot length of the axially wide portion. In the half link chain according to the fourth aspect, during the operation of the half link chain, the axially narrow portion receives all or most of the sprocket tooth of the sprocket. With this configuration, the holding force of the half link chain on the sprocket tooth can be further improved. In addition, during the operation of the half link chain, the axially wide portion receives all or most of the sprocket tooth of the sprocket, so that the holding force of the half link chain on the sprocket tooth having a large thickness can be improved.According to a fifth aspect of the present invention, in the half link chain according to any one of the first to fourth aspects, the half link chain is configured as follows. In the assembled state of the half link chain, the corresponding one of the axially narrow portion and the axially wide portion has an axial slot length with respect to the axial direction. A ratio of an axial slot length to an axial chain engagement width of the sprocket tooth is greater than or equal to 1.0 and less than or equal to 1.2. in the half link chain according to the fifth aspect, the ratio of the axial slot length to the axial chain engagement width of the sprocket tooth in the sprocket is set as described above, whereby the holding force of the half link chain on the sprocket tooth can be improved.According to a sixth aspect of the present invention, in the half link chain according to any one of the first to fifth aspects, the half link chain is configured as follows. The first pin has a first pin end and a second pin end that is opposite to the first pin end with respect to the axial direction in the assembled state. The second pin has a third pin end and a fourth pin end that is opposed to the third pin end with respect to the axial direction in the assembled state. The first pin is secured to the first link by swaging the first pin end of the first pin. The first pin is secured to the second link by swaging the second pin end of the first pin. The second pin is secured to a first adjacent link by swaging the third pin end of the second pin. The second pin is secured to a second adjacent link by swaging the fourth pin end of the second pin. In the half link chain according to the sixth aspect, the first pin is fixed to the first link and the second link by swaging. The second pin is fixed to the first adjacent link and to the second adjacent link by swaging. In this case, the first link and the second link are coupled to the first adjacent link and the second adjacent link, respectively. With this configuration, the strength of the half link chain can be improved.According to a seventh aspect of the present invention, in the half link chain according to any one of the first to sixth aspects, the half link chain further includes a roller. The roller is configured to be arranged around the sleeve and between the first chain link and the second chain link with respect to the axial direction in the assembled state. In the half link chain according to the seventh aspect, the provision of the roller can improve the driving efficiency of the half link chain.According to an eighth aspect of the present invention, in the half link chain according to any one of the first to seventh aspects, the half link chain is formed as follows. The axially narrow portion is formed at least between the first inner link portion of the first link and the second inner link portion of the second link in the axial direction. The axially wide portion is formed at least between the first outer link portion of the first link and the second outer link portion of the second link in the axial direction. In the half link chain according to the eighth aspect, the above-described configuration of the axially wide portion enables a simpler configuration of the half link chain.According to a ninth aspect of the present invention, the half link chain according to any one of the first to eighth aspects is configured as follows. The first outer link portion of the first link has a first outer link axial thickness defined in the axial direction. The first inner link portion of the first link has a first inner link axial thickness defined in the axial direction. A first thickness difference between the first outer-link axial thickness and the first inner-link axial thickness is less than or equal to 0.2 mm. In the half link chain according to the ninth aspect, setting the first thickness difference between the first outer link axial thickness and the first inner link axial thickness as described above can improve the manufacturing efficiency of the half link chain.According to a tenth aspect of the present invention, in the half link chain according to any one of the first to ninth aspects, the half link chain is configured as follows. The second outer link portion of the second link has a second outer link axial thickness defined in the axial direction. The second inner link portion of the second link has a second inner link axial thickness defined in the axial direction. A second thickness difference between the second outer-link axial thickness and the second inner-link axial thickness is less than or equal to 0.2 mm. In the half link chain according to the tenth aspect, setting the second thickness difference between the second outer link axial thickness and the second inner link axial thickness as described above can improve the manufacturing efficiency of the half link chain.According to the present invention, a half link chain for a human-powered vehicle can improve the holding force on a sprocket tooth.A more complete understanding of the invention and many attendant advantages thereof will be readily appreciated as the same becomes better understood from the following detailed description taken in conjunction with the accompanying drawings, in which FIG. 1 is a side view of a half link chain according to first to fifth embodiments of the present invention in an assembled state to a bicycle; FIG. 2 is a perspective view of the half link chain for describing the first to fifth embodiments; FIG. 3 is an exploded perspective view of the half link chain for describing the first to fifth embodiments; FIG. 4 is a cross-sectional view of the half link chain for describing the first to fifth embodiments; FIG. 5 is a cross-sectional view of the half link chain for describing the first to fifth embodiments; FIG. 6 is an exploded perspective view of a first link and a second link for describing the half link chain according to the second embodiment; FIG. 7 is a cross-sectional view for describing the half link chain according to the third embodiment; and FIG. 8 is a cross-sectional view of a half link chain for describing a modified example of the third embodiment.Embodiments of the present invention will now be described with reference to the accompanying drawings, in which like reference numerals designate corresponding or identical elements throughout the several drawings.As illustrated in FIG. 1, a bicycle 1 is used as an example of a human-powered vehicle. The bicycle 1 includes a frame 3, a handlebar 5, a front wheel 7, a rear wheel 9, a transmission 11, and a drive portion 13.As shown in FIG. 1, the handles 5 are coupled to the front wheel 7 via a front fork 17. On the front wheel 7, a front tire 7 ais mounted. The rear wheel 9 is rotatably mounted on a rear portion of the frame 3. On the rear wheel 9, a rear tire 9a is mounted. The gear shift 11 is mounted on the handlebar 5. The gear shift 11 actuates a derailleur 18 and a derailleur 19 via a cable.The drive portion 13 basically includes a rear hub assembly 20, a rear sprocket assembly 21, and a crank assembly 22. The rear sprocket assembly 21 is mounted to the rear hub assembly 20. The rear sprocket assembly 21 includes at least one rear sprocket.The crank assembly 22 includes a crank arm 23 and a front sprocket assembly 24. the crank arm 23 is rotatably supported at a lower portion of the frame 3. The front sprocket assembly 24 is mounted on the crank arm 23 so as to rotate together with the crank arm 23. The front sprocket assembly 24 includes at least one front sprocket. The half link chain 15 is stretched over a rear sprocket of the rear sprocket assembly 21 and a front sprocket of the front sprocket assembly 24.The half link chain 15 used for the bicycle 1 is formed as illustrated in FIGS. 2 and 3. In FIG. 2, reference numerals of configurations of a first link 31 that cannot be illustrated in the drawing are given in parentheses together with reference numerals of configurations of a second link 33 that correspond to the configurations of the first link 31.As illustrated in FIGS. 2 and 3, the half link chain 15 for the bicycle 1 includes the first link 31 including a first outer link portion 43 having a first outer link opening 61 with a first outer link center axis X 11, a first inner link portion 45 having a first inner link opening 63 with a first inner link center axis X 12, a first axially outward facing surface 47 with respect to an axial direction AD defined by the first outer link center axis X 11 and the first inner link center axis X 12, and a first axially inward facing surface 49 opposite the first axially outward facing surface 47 with respect to the axial direction AD, the second link 33 having a second outer link portion 51, which includes a second outer link opening 65 having a second outer link center axis X 21, a second inner link portion 53 having a second inner link opening 67 having a second inner link center axis X 22, a second axially outward facing surface 55 with respect to the axial direction, and a second axially inward facing surface 57 that is opposed to the second axially outward facing surface 55 with respect to the axial direction and is configured to face the first axially inward facing surface 49 in the axial direction AD in an assembled state of the half link chain 15, and a sleeve 35 configured to be inserted into the first inner link opening 63 and the second inner link opening 67 in the assembled state of the half link chain 15.As illustrated in FIGS. 2 and 3, in the assembled state of the half link chain 15, the second outer link center axis X 21 is configured to be coaxial with the first outer link center axis X 11. In the assembled state of the half link chain 15, the second inner link center axis X 22 is configured to be coaxial with the first inner link center axis X 12.As illustrated in FIGS. 2 and 3, the first outer member portion 43 and the first inner member portion 45 are at least partially offset from each other in the axial direction AD, so that the first outer member opening 61 and the first inner member opening 63 are offset from each other in the axial direction AD. The second outer member portion 51 and the second inner member portion 53 are at least partially offset from each other in the axial direction AD, so that the second outer member opening 65 and the second inner member opening 67 are offset from each other in the axial direction AD.As shown in FIG. 3, the sleeve 35 has a sleeve cavity 71, a first sleeve end 73, and a second sleeve end 75 that, in the assembled state of the half link chain 15, is opposed to the first sleeve end 73 with respect to the axial direction AD. As illustrated in FIG. 4, in the assembled state of the half link chain 15, the first sleeve end 73 is configured to be disposed in the first inner link opening 63 of the first link 31. In the assembled state of the half link chain 15, the second sleeve end 75 is configured to be disposed in the second inner link opening 67 of the second link 33.As illustrated in FIGS. 3 and 4, the sleeve 35 is fixed to at least one of the first link 31 and the second link 33, corresponding to at least one of the first sleeve end 73 and the second sleeve end 75, by swaging at least one of the first sleeve end 73 and the second sleeve end 75.As illustrated in FIGS. 2 to 4, the half link chain 15 includes the first link 31, the second link 33, and the sleeve 35. the half link chain 15 further includes a first pin 37 and a second pin 39. the half link chain 15 further includes a roller 41.In the present embodiment, the first link 31, the second link 33, the sleeve 35, the second pin 39, and the roller 41 constitute a main unit of the half link chain 15. the half link chain 15 is formed by continuously connecting the one main unit.In the following description, the feature "adjacent" is added to each of constituent elements of an adjacent unit adjacent to the one unit. Each configuration of the adjacent unit is the same as each configuration of the above-described main unit.As shown in Figs. 2 to 4, each configuration of the adjacent unit is assigned a character N. For example, a first adjacent link 31N is a link adjacent to the first link 31 in a longitudinal direction LD of the half link chain 15. A second adjacent link 33N is a link adjacent to the second link 33 in the longitudinal direction LD of the half link chain 15.The longitudinal direction LD of the half link chain 15 is defined as a direction orthogonal to the axial direction AD in a downward view in which the half link chain 15 is viewed from above in the assembled state of the half link chain 15. A second pin 39N of the adjacent unit functions as the first pin 37. the first pin 37 can be regarded as a configuration of the main unit. A first pin 37N of the adjacent unit functions as the second pin 39.As illustrated in FIGS. 2 to 4, the first link 31 includes the first outer link portion 43, the first inner link portion 45, the first axially outward facing surface 47, and the first axially inward facing surface 49. The first inner member opening 63 penetrates the first inner member portion 45 in the axial direction AD.In the present embodiment, the first outer member portion 43 and the first inner member portion 45 are offset from each other in the axial direction AD. In particular, in the assembled state of the half link chain 15, the first inner link portion 45 is offset with respect to the first outer link portion 43 in the axial direction AD in the direction of the second chain link 33. That is, in the assembled state of the half link chain 15, the first inner link opening 63 is offset toward the second link 33 side relative to the first outer link opening 61.In the assembled state of the half link chain 15, the first axially outward facing surface 47 faces away from the second link 33 in the axial direction AD. That is, in the assembled state of the half link chain 15, the first axially outward facing surface 47 forms an outward facing surface of the first link 31 in the half link chain 15. In the assembled state of the half link chain 15, the first axially inward facing surface 49 faces the second link 33 in the axial direction AD. That is, in the assembled state of the half link chain 15, the first axially inward facing surface 49 forms an inward facing surface of the first link 31 in the half link chain 15.As illustrated in FIGS. 2 to 4, the second link 33 includes the second outer link portion 51, the second inner link portion 53, the second axially outward facing surface 55, and the second axially inward facing surface 57. the second outer link opening 65 penetrates the second outer link portion 51 in the axial direction AD. The second inner member opening 67 penetrates the second inner member portion 53 in the axial direction AD.In the present embodiment, the second outer member portion 51 and the second inner member portion 53 are offset from each other in the axial direction AD. In particular, in the assembled state of the half link chain 15, the second inner link portion 53 is offset from the second outer link portion 51 in the axial direction AD toward the first link 31. That is, in the assembled state of the half link chain 15, the second inner link opening 67 is offset toward the first link 31 side relative to the second outer link opening 65.In the assembled state of the half link chain 15, the second axially outward facing surface 55 faces away from the first link 31 in the axial direction AD. That is, in the assembled state of the half link chain 15, the second axially outward facing surface 55 forms an outward facing surface of the second link 33 in the half link chain 15. in the assembled state of the half link chain 15, the second axially inward facing surface 57 faces the first link 31 in the axial direction AD. That is, in the assembled state of the half link chain 15, the second axially inward facing surface 57 forms an inward facing surface of the second link 33 in the half link chain 15.As illustrated in FIG. 3, the sleeve 35 is formed substantially in a cylindrical shape. The sleeve cavity 71 is defined by a sleeve inner surface 35 a. As illustrated in FIG. 4, the sleeve 35 is fixed to at least one of the first link 31 and the second link 33 by swaging. In the present embodiment, the sleeve 35 is fixed to both the first link 31 and the second link 33 by swaging.As illustrated in FIG. 4, the sleeve 35 is disposed in the first inner link opening 63 of the first link 31 and the second inner link opening 67 of the second link 33. Specifically, the first sleeve end 73 is disposed in the first inner link opening 63 of the first link 31. Preferably, the first sleeve end 73 is press-fitted into the first inner link opening 63 of the first link 31. The second sleeve end 75 is disposed in the second inner link opening 67 of the second link 33. Preferably, the first sleeve end 73 is press-fitted into the second inner link opening 67 of the second link 33.In this state, the first sleeve end 73 is stowed with the first axially outward facing surface 47 of the first link 31. The second sleeve end 75 is stowed with the second axially outward facing surface 55 of the second link 33. That is, after the sleeve 35 is disposed in the first inner link opening 63 of the first link 31 and the second inner link opening 67 of the second link 33, the first sleeve end 73 and the second sleeve end 75 are stored. As described above, the sleeve 35 is fixed to both the first link 31 and the second link 33 by swaging both the first sleeve end 73 and the second sleeve end 75.The sleeve 35 may be fixed to the first link 31 by pressing the first sleeve end 73 into the first inner link opening 63. In this case, the sleeve 35 is fastened to the second chain link 33 by upsetting the second sleeve end 75. The sleeve 35 may be secured to the second link 33 by pressing the second sleeve end 75 into the second inner link aperture 67. In this case, the sleeve 35 is fastened to the first chain link 31 by upsetting the first sleeve end 73.As shown in FIGS. 2 to 4, the first pin 37 is configured to be inserted into the first outer link opening 61 of the first link 31 and the second outer link opening 65 of the second link 33 in the assembled state of the half link chain 15. The first pin 37 is configured to be inserted into an adjacent bushing cavity 71N of an adjacent bushing 35N in the assembled state of the half link chain 15.Specifically, as illustrated in FIG. 3, the first pin 37 is formed in a substantially tubular shape. As illustrated in FIGS. 2 and 3, the first pin 37 has a first pin end 77 and a second pin end 78 that, in the assembled state of the half link chain 15, is opposed to the first pin end 77 with respect to the axial direction AD.As shown in FIG. 4, the first pin 37 is inserted into the adjacent sleeve cavity 71N. In this state, the first pin end 77 is disposed in the first outer link opening 61 of the first link 31. Preferably, the first pin end 77 is press-fitted into the first outer link opening 61 of the first link 31. The first pin 37 is fastened to the first chain link 31 by upsetting the first pin end 77 of the first pin 37.As shown in FIG. 4, the second pin end 78 is disposed in the second outer link opening 65 of the second link 33. Preferably, the second pin end 78 is press fit into the second outer link opening 65 of the second link 33. The first pin 37 is fixed to the second link 33 by swaging the second pin end 78 of the first pin 37.Thus, after the first pin 37 is disposed in the first outer link opening 61 of the first link 31 and in the second outer link opening 65 of the second link 33, the first pin end 77 and the second pin end 78 are swaged. As described above, the first pin 37 is fixed to both the first link 31 and the second link 33 by swaging the first pin end 77 and the second pin end 78.The first pin 37 may be fixed to the first link 31 and the second link 33 without upsetting by pressing the first pin end 77 into the first outer link opening 61 of the first link 31 and the second pin end 78 into the second outer link opening 65 of the second link 33.The first pin 37 may be fixed to the first link 31 by only swaging the first pin end 77. In this case, the second pin end 78 is not swaged but pressed into the second outer link opening 65 of the second link 33.The first pin 37 may be secured to the second link 33 by only swaging the second pin end 78. In this case, the first pin end 77 is press-fitted into the first outer link opening 61 of the first link 31 without being crushed.As illustrated in FIG. 3, the second pin 39 is configured to be inserted into the first inner link hole 63 of the first link 31, the second inner link hole 67 of the second link 33, and the bushing cavity 71 of the bushing 35 in the assembled state of the half link chain 15.As illustrated in FIG. 3, the second pin 39 is formed in a substantially tubular shape. As shown in FIGS. 2 and 3, the second pin 39 has a third pin end 79 and a fourth pin end 80 that, in the assembled state of the half link chain 15, is opposed to the third pin end 79 with respect to the axial direction AD.As shown in FIG. 4, the second pin 39 is inserted into the sleeve cavity 71. In this state, the third pin end 79 is disposed in a first adjacent outer link opening 61N of the first adjacent link 31N. Preferably, the third pin end 79 is press-fitted into the first adjacent outer link opening 61N of the first adjacent link 31N. The second pin 39 is fixed to the first adjacent link 31N by swaging the third pin end 79 of the second pin 39. In this configuration, the first adjacent link 31N is coupled to the first link 31 via the second pin 39.As shown in FIG. 4, the fourth pin end 80 is disposed in the second adjacent outer link opening 65N of the second adjacent link 33N. Preferably, the fourth pin end 80 is press-fitted into the second adjacent outer link opening 65N of the second adjacent link 33N. The second pin 39 is fixed to the second adjacent link 33N by swaging the fourth pin end 80 of the second pin 39. In this configuration, the second adjacent link 33N is coupled to the second link 33 via the second pin 39.The second pin 39 may be fixed to the first adjacent link 31N and the second adjacent link 33N without being swaged by pressing the third pin end 79 into the first adjacent outer link opening 61N of the first adjacent link 31N and pressing the fourth pin end 80 into the second adjacent outer link opening 65N of the second adjacent link 33N.The second pin 39 may be fixed to the first adjacent link 31N by only upsetting the third pin end 79. In this case, the fourth pin end 80 is press-fitted into the second adjacent outer link opening of the second adjacent link 33N.The second pin 39 may be attached to the second adjacent link 33N by only swaging the fourth pin end 80. In this case, the third pin end 79 is press-fitted into the first adjacent outer link opening of the first adjacent link 31N.As illustrated in FIG. 4, in the assembled state of the half link chain 15, the roller 41 is formed to be disposed around the sleeve 35 and between the first link 31 and the second link 33 with respect to the axial direction AD.As illustrated in FIG. 3, the roller 41 is formed in a substantially tubular shape. The roller 41 is disposed on an outer circumferential surface of the sleeve 35 so as to be rotatable relative to the sleeve 35. As illustrated in FIGS. 3 and 4, the roller 41 is disposed between the first inner link portion 45 of the first link 31 and the second inner link portion 53 of the second link 33 with respect to the axial direction AD.As illustrated in FIG. 5, in the assembled state of the half link chain 15, a tooth engaging slot 81 is formed between the first link 31 and the second link 33 with respect to the axial direction AD. The tooth engaging slot 81 has an axially narrow portion 83 and an axially wide portion 85.The axially narrow portion 83 is formed at least between the first inner link portion 45 of the first link 31 and the second inner link portion 53 of the second link 33 in the axial direction AD.In the present embodiment, the axially narrow portion 83 is formed between the first inner link portion 45 of the first link 31 and the second inner link portion 53 of the second link 33 in the axial direction AD. Specifically, the axially narrow portion 83 is formed between the first axially inward facing surface 49 of the first inner link portion 45 and the second axially inward facing surface 57 of the second inner link portion 53 in the axial direction AD.As illustrated in FIG. 5, the axially wide portion 85 is formed at least between the first outer link portion 43 of the first link 31 and the second outer link portion 51 of the second link 33 in the axial direction AD. In a downward view in which the half link chain 15 is viewed from above, an axial distance W 1 of the axially wide portion 85 is larger than an axial distance W 2 of the axially narrow portion 83.In the present embodiment, the axially wide portion 85 is formed between the first outer link portion 43 of the first link 31 and the second outer link portion 51 of the second link 33 in the axial direction AD. Specifically, the axially wide portion 85 is formed in the axial direction AD between the first axially inward facing surface 49 of the first outer member portion 43 and the first axially inward facing surface 49 of the second outer member portion 51.A configuration of a second embodiment is the same as the configuration of the first embodiment except for the configuration of the half link chain 15 according to the first embodiment. Therefore, in the second embodiment, a configuration different from the configuration of the first embodiment in the half link chain 15 according to the first embodiment will be described.In the second embodiment, configurations that are the same as or similar to those of the first embodiment are denoted by the same reference numerals. In the second embodiment, the description of a configuration identical or similar to that of the first embodiment may be omitted. In this case, the description of the configuration omitted in the second embodiment is based on the description of the first embodiment.As illustrated in FIGS. 2 to 5, a half link chain 115 for the bicycle 1 includes the first outer link portion 43 having the first outer link opening 61 with the first outer link center axis X 11, the first inner link portion 45 having the first inner link opening 63 with the first inner link center axis X 12, and the first chain link 31 having the first outer link center axis X 11, the first axially outward facing surface 47 with respect to the axial direction AD defined by the first outer link center axis X 11 and the first inner link center axis X 12, and the first axially inward facing surface 49 with respect to the first axially outward facing surface 47 with respect to the axial direction AD.As shown in FIGS. 2 to 5, the first outer member portion 43 and the first inner member portion 45 are at least partially offset from each other in the axial direction AD, so that the first outer member opening 61 and the first inner member opening 63 are offset from each other in the axial direction AD.As illustrated in FIG. 6, the first link 31 further includes a first outer circumferential surface 50 coupling the first axially outward surface 47 and the first axially inward surface 49, and at least one first chamfered portion 87 formed between at least one of the first axially outward surface 47 and the first axially inward surface 49 and the first outer circumferential surface 50.As illustrated in FIGS. 2 to 5, the half link chain 115 includes the first link 31 and the second link 33. the half link chain 115 further includes the sleeve 35. the half link chain 115 further includes the first pin 37 and the second pin 39. the half link chain 115 further includes the roller 41.In the second embodiment, the configurations of the first link 31 are the same as the configurations of the first embodiment except for the configuration of the first outer circumferential surface 50 and the configuration of the at least one first chamfered portion 87. the configurations of the second link 33 correspond to the configurations of the first embodiment except for a configuration of a second outer circumferential surface 88 described later and a configuration of at least one second chamfered portion 89 described later. The configurations of the sleeve 35, the configurations of the first pin 37, the configurations of the second pin 39, the configurations of the roller 41, and the configurations of the tooth engagement slot 81 are the same as in the first embodiment.As illustrated in FIG. 6, the first link 31 includes the first outer link portion 43, the first inner link portion 45, the first axially outward facing surface 47, the first axially inward facing surface 49, the first outer circumferential surface 50, and the at least one first chamfered portion 87.As described above, the first outer peripheral surface 50 couples the first axially outward facing surface 47 and the first axially inward facing surface 49, and the first outer peripheral surface 50 is formed so as to surround an end side of the first axially outward facing surface 47 and an end side of the first axially inward facing surface 49.The at least one first chamfered portion 87 is formed between the first outer circumferential surface 50 and the first axially inward facing surface 49. The at least one first chamfered portion 87 is formed between the first outer circumferential surface 50 and the first axially outward facing surface 47. In the present embodiment, the at least one first chamfered portion 87 is formed between the first outer circumferential surface 50 and each of the first axially outward facing surface 47 and the first axially inward facing surface 49.As illustrated in FIG. 6, the at least one first chamfered portion 87 includes a plurality of first chamfered portions 87. in the present embodiment, the at least one first chamfered portion 87 includes two first chamfered portions 87A and 87B.The first chamfered portion 87A is formed in the first inner link portion 45. The first chamfered portion 87A is formed between the first outer circumferential surface 50 and the first axially inward facing surface 49 of the first inner link portion 45. The plurality of first chamfered portions 87A may be formed between the first outer circumferential surface 50 and the first axially inward facing surface 49 of the first inner link portion 45. Between the first outer circumferential surface 50 and the first axially inward facing surface 49 of the first outer member portion 43, a single or the plurality of first chamfered portions 87A may be formed.The first chamfered portion 87B is formed in the first outer link portion 43. The first chamfered portion 87B is formed between the first outer circumferential surface 50 and the first axially outward facing surface 47 of the first outer member portion 43. The plurality of first chamfered portions 87B may be formed between the first outer circumferential surface 50 and the first axially outward facing surface 47 of the first outer member portion 43. Between the first outer circumferential surface 50 and the first axially inward facing surface 49 of the first inner link portion 45, a single or the plurality of first chamfered portions 87B may be formed.As illustrated in FIG. 6, the second link 33 includes the second outer link portion 51, the second inner link portion 53, the second axially outward facing surface 55, and the second axially inward facing surface 57. the second link 33 has the second outer circumferential surface 88 and the at least one second chamfered portion 89. the second outer circumferential surface 88 couples the second axially outward facing surface 55 and the second axially inward facing surface 57. the second outer circumferential surface 88 is formed so as to surround an end side of the second axially outward facing surface 55 and an end side of the second axially inward facing surface 57.The at least one second chamfered portion 89 is formed between the second outer circumferential surface 88 and at least one of the second axially outward facing surface 55 and the second axially inward facing surface 57. The at least one second chamfered portion 89 is formed between the second outer circumferential surface 88 and the second axially inward facing surface 57. The at least one second chamfered portion 89 is formed between the second outer circumferential surface 88 and the second axially outward facing surface 55. In the present embodiment, the at least one second chamfered portion 89 is formed between the second outer circumferential surface 88 and each of the second axially outward facing surface 55 and the second axially inward facing surface 57.As illustrated in FIG. 6, the at least one second chamfered portion 89 includes a plurality of second chamfered portions 89. In the present embodiment, the at least one second chamfered portion 89 includes two second chamfered portions 89A and 89B.The second chamfered portion 89A is formed in the second inner link portion 53. The second chamfered portion 89A is formed between the second outer circumferential surface 88 and the second axially inward facing surface 57 of the second inner link portion 53. A plurality of second chamfered portions 89A may be formed between the second outer circumferential surface 88 and the second axially inward facing surface 57 of the second inner link portion 53. Between the second outer circumferential surface 88 and the second axially inward facing surface 57 of the second outer member portion 51, a single or the plurality of second chamfered portions 89A may be formed.The second chamfered portion 89B is formed in the second outer link portion 51. The second chamfered portion 89B is formed between the second outer circumferential surface 88 and the second axially outward facing surface 55 of the second outer member portion 51. Between the second outer circumferential surface 88 and the second axially outward facing surface 55 of the second outer member portion 51, a plurality of second chamfered portions 89B may be formed. Between the second outer circumferential surface 88 and the second axially outward facing surface 55 of the second inner link portion 53, a single or the plurality of second chamfered portions 89B may be formed.A configuration of a third embodiment is the same as the configuration of the first embodiment except for the configuration of the half link chain 15 according to the first embodiment. Therefore, in the third embodiment, a configuration different from that of the first embodiment will be described in the half link chain 15 according to the first embodiment.In the third embodiment, configurations that are the same as or similar to those of the first embodiment are denoted by the same reference numerals. In the third embodiment, the description of a configuration identical or similar to that of the first embodiment may be omitted. In this case, the description of the configuration omitted in the third embodiment is based on the description of the first embodiment.As illustrated in FIGS. 2 to 5, a half link chain 215 for the bicycle 1 includes the first link 31 including the first outer link portion 43 having the first outer link opening 61 with the first outer link center axis X 11, the first inner link portion 45 having the first inner link opening 63 with the first inner link center axis X 12, the first axially outward facing surface 47 with respect to an axial direction AD defined by the first outer link center axis X 11 and the first inner link center axis X 12, and the first axially inward facing surface 49 opposite to the first axially outward facing surface 47 with respect to the axial direction AD. The half link chain 215 for the bicycle 1 further includes the second link 33 including the second outer link portion 51 having the second outer link opening 65 with the second outer link center axis X 21, the second inner link portion 53 having the second inner link opening 67 with the second inner link center axis X 22, the second axially outward facing surface 55 with respect to the axial direction AD, and the second axially inward facing surface 57 that is opposed to the second axially outward facing surface 55 with respect to the axial direction AD and configured to face the first axially inward facing surface 49 in the axial direction AD in an assembled state of the half link chain 215. The half link chain 215 for the bicycle 1 further includes the sleeve 35 configured to be inserted into the first inner link opening 63 and the second inner link opening 67 in the assembled state of the half link chain 215. The half link chain 215 for the bicycle 1 further includes the first pin 37 configured to be inserted into the first outer link opening 61 of the first link 31 and the second outer link opening 65 of the second link 33 in the assembled state of the half link chain 215. The half link chain 215 for the bicycle 1 further includes the second pin 39 configured to be inserted into the first inner link opening 63 of the first link 31 and the second inner link opening 67 of the second link 33 in the assembled state of the half link chain 215.As illustrated in FIGS. 2 to 5, in the assembled state of the half link chain 215, the second outer link center axis X 21 is configured to be coaxial with the first outer link center axis X 11. In the assembled state of the half link chain 215, the second inner link center axis X 22 is configured to be coaxial with the first inner link center axis X 12.As shown in FIGS. 2 to 5, the first outer member portion 43 and the first inner member portion 45 are at least partially offset from each other in the axial direction AD, so that the first outer member opening 61 and the first inner member opening 63 are offset from each other in the axial direction AD. The second outer member portion 51 and the second inner member portion 53 are at least partially offset from each other in the axial direction AD, so that the second outer member opening 65 and the second inner member opening 67 are offset from each other in the axial direction AD.As illustrated in FIG. 7, the sleeve 35 includes the sleeve cavity 71 defined by the sleeve inner surface 35 a, the first sleeve end 73, the second sleeve end 75 that faces the first sleeve end 73 in the axial direction AD in the assembled state of the half link chain 215, and a hardened sleeve layer 91 formed on the sleeve inner surface 35 a.In the assembled state of the half link chain 215, the first sleeve end 73 is configured to be disposed in the first inner link opening 63 of the first link 31. In the assembled state of the half link chain 215, the second sleeve end 75 is configured to be disposed in the second inner link opening 67 of the second link 33.As illustrated in FIG. 7, the first pin 37 has a first pin radially outward surface 37 awith respect to the first outer link center axis X 11, and a first hardened pin layer 37 bformed on the first pin radially outward surface 37 a. The second pin 39 is inserted into the bushing cavity 71 of the bushing 35 in the assembled state of the half link chain 215 and has a second pin radially outward surface 39 awith respect to the second outer link center axis X 21 and a second hardened pin layer 39 bformed on the second pin radially outward surface 39 a.In the assembled state of the half link chain 215, the second pin surface 39 afacing radially outward is configured to slide on the sleeve inner surface 35 a.In the third embodiment, configurations of the first link 31 and configurations of the second link 33 are the same as the configurations thereof in the first embodiment. Configurations of the sleeve 35, configurations of the first pin 37, and configurations of the second pin 39 are the same as their configurations in the first embodiment, except configurations of the hardened layer described later. Configurations of the roller 41 and configurations of the tooth engagement slot 81 are the same as the configurations thereof in the first embodiment.As illustrated in FIGS. 2 to 5 and 7, the sleeve 35 includes the sleeve cavity 71, the first sleeve end 73, the second sleeve end 75, and the hardened sleeve layer 91. the configuration of the sleeve 35 is the same as that of the first embodiment except for the hardened sleeve layer 91.In the present embodiment, the sleeve 35 illustrated in FIG. 7 is made of a metal. The hardened shell layer 91 of the shell 35 is formed by any one of vanadium treatment, chromium treatment, boron treatment, nitriding treatment, and nitriding-sulfur treatment. The hardened sleeve layer 91 of the sleeve 35 has a sleeve hardness of 1000 Hv or more and 3500 Hv or less.The first hardened pin layer 37 bof the first pin 37 is formed by any one of the following treatments: vanadium treatment, chromium treatment, boron treatment, nitriding treatment, and nitriding-sulfur treatment. The first hardened pin layer 37 bof the first pin 37 has a first pin hardness of greater than or equal to 1000 Hv and less than or equal to 3500 Hv.The second hardened pin layer 39 bof the second pin 39 is formed by any one of the following treatments: vanadium treatment, chromium treatment, boron treatment, nitriding treatment, and nitriding-sulfur treatment. The second pin hardened layer 39 bof the second pin 39 has a second pin hardness equal to or higher than 1000 Hv and equal to or lower than 3500 Hv.In the vanadium treatment, vanadium diffuses and penetrates into the sleeve inner surface 35 ato form a vanadium carbide layer on the sleeve inner surface 35 a. The vanadium treatment improves wear resistance. The vanadium treatment suppresses the formation of layer defects such as a pore. Excellent resistance to molten aluminum is achieved by the vanadium treatment.In the chromium treatment, chromium diffuses and penetrates into the sleeve inner surface 35 ato form a chromium diffusion and permeation layer on the sleeve inner surface 35 a. The chromium treatment improves properties such as wear resistance, seizure resistance and corrosion resistance.In the boron treatment, boric acid diffuses and penetrates into the sleeve inner surface 35 ato form a boride layer on the sleeve inner surface 35 a. The boron treatment improves properties such as wear resistance and seizure resistance.In the nitriding treatment, a thin hardened layer of a nitride compound is formed on the sleeve inner surface 35 aby infiltrating nitrogen into the sleeve inner surface 35 a. The nitriding treatment improves the hardness of the sleeve inner surface 35 a.In the nitriding sulfur treatment, a nitride compound layer is formed on the sleeve inner surface 35 aby a gas soft nitriding treatment. The sulfur treatment is performed on the nitride compound layer to form a sulfide layer. The nitriding-sulfur treatment reduces frictional resistance and improves wear resistance (lubricity and welding strength).In a modified example of the third embodiment, the example in which the sleeve 35 is inserted into the first inner member hole 63 and the second inner member hole 67 has been described. In a modified example, as illustrated in FIG. 8, a half link chain 315 is formed without using the sleeve 35. Configurations that are the same as or similar to the configurations of the third embodiment will be denoted by the same reference numerals in the present modified example, and redundant descriptions will be omitted.In the present modified example, the configurations of the first pin 37 and the configurations of the second pin 39 are the same as in the third embodiment except for the configurations of the following cured layer. The configuration of the roller 41 and the configuration of the tooth engaging slot 81 are the same as in the third embodiment.As illustrated in FIG. 8, the half link chain 315 for the bicycle 1 includes the first link 31 including the first outer link portion 43 having the first outer link opening 61 with the first outer link center axis X 11, the first inner link portion 45 having the first inner link opening 63 with the first inner link center axis X 12, the first axially outward facing surface 47 with respect to the axial direction AD defined by the first outer link center axis X 11 and the first inner link center axis X 12, and the first axially inward facing surface 49 opposite to the first axially outward facing surface 47 with respect to the axial direction AD. The half link chain 315 for the bicycle 1 further includes the second link 33 including the second outer link portion 51 having the second outer link opening 65 with the second outer link center axis X 21, the second inner link portion 53 having the second inner link opening 67 with the second inner link center axis X 22, the second axially outward facing surface 55 with respect to the axial direction AD, and the second axially inward facing surface 57 that is opposed to the second axially outward facing surface 55 with respect to the axial direction AD and configured to face the first axially inward facing surface 49 in the axial direction AD in an assembled state of the half link chain 315. The half link chain 315 for the bicycle 1 further includes the first pin 37 configured to be inserted into the first outer link opening 61 of the first link 31 and the second outer link opening 65 of the second link 33 in the assembled state of the half link chain 315. The half link chain 315 for the bicycle 1 further includes the second pin 39 configured to be inserted into the first inner link opening 63 of the first link 31 and the second inner link opening 67 of the second link 33 in the assembled state of the half link chain 315.As illustrated in FIG. 8, in the assembled state of the half link chain 315, the second outer link center axis X 21 is configured to be coaxial with the first outer link center axis X 11. In the assembled state of the half link chain 315, the second inner link center axis X 22 is formed to be coaxial with the first inner link center axis X 12.The first outer member portion 43 and the first inner member portion 45 are at least partially offset from each other in the axial direction AD such that the first outer member opening 61 and the first inner member opening 63 are offset from each other in the axial direction AD. The second outer member portion 51 and the second inner member portion 53 are at least partially offset from each other in the axial direction AD, so that the second outer member opening 65 and the second inner member opening 67 are offset from each other in the axial direction AD.As illustrated in FIG. 8, the second pin 39 has the second pin radially outward surface 39 awith respect to the second outer link center axis X 21 and the second hardened pin layer 39 bformed on the second pin radially outward surface 39 a.The first link 31 defines the first inner link opening 63 and has a first inner link opening surface 63 aformed to slide on the second radially outward facing pin surface 39 aof the second pin 39, and a first hardened opening layer 63 bformed on the first inner link opening surface 63 a.The second link 33 defines the second inner link opening 67 and has a second inner link opening surface 67 aformed to slide on the second radially outward facing pin surface 39 aof the second pin 39, and a second hardened opening layer 67formed on the second inner link opening surface 67 a.In the present embodiment, the first link 31 illustrated in FIG. 8 is made of a metal. The first link 31 includes a first axially protruding portion 32 with respect to the axial direction AD. The first axially protruding portion 32 surrounds the first inner member opening 63 and extends in the axial direction AD from the first axially inward facing surface 49, so that the first inner member opening surface 63 aextends in the axial direction AD along the first axially protruding portion 32.As illustrated in FIG. 8, the first axially protruding portion 32 is integrally formed with the first inner link portion 45 of the first link 31. The first axially protruding portion 32 extends in the axial direction AD from the first axially inward facing surface 49 so as to surround the first inner member opening 63. An inner surface of the first axially protruding portion 32 in the axial direction AD is disposed to face the outer circumferential surface of the second pin 39. The first inner member opening surface 63 ais formed by an inner surface of the first inner member opening 63 and the inner surface of the first axially protruding portion 32.The first hardened opening layer 63 bof the first link 31 is formed by any one of vanadium treatment, chromium treatment, boron treatment, nitriding treatment, and nitriding sulfur treatment. The first hardened opening layer 63 bof the first link 31 has a first pin hardness of greater than or equal to 1000 Hv and less than or equal to 3500 Hv.The second link 33 shown in FIG. 8 is made of a metal. The second link 33 has a second axially protruding portion 34 with respect to the axial direction AD. The second axially protruding portion 34 surrounds the second inner member opening 67 and extends in the axial direction AD from the second axially inward facing surface 57 so that the second inner member opening surface 67 aextends in the axial direction AD along the second axially protruding portion 34.As illustrated in FIG. 8, the second axially protruding portion 34 is integrally formed with the second inner link portion 53 of the second link 33. The second axially protruding portion 34 extends in the axial direction AD from the second axially inward facing surface 57 so as to surround the second inner member opening 67. An inner surface of the second axially protruding portion 34 is disposed to be opposed to the outer circumferential surface of the second pin 39. The second inner-member opening surface 67 ais formed by an inner surface of the second inner-member opening 67 and an inner surface of the second axially protruding portion 34.The second hardened opening layer 67 bof the second link 33 is formed by any one of the following treatments: vanadium treatment, chromium treatment, boron treatment, nitriding treatment, and nitriding-sulfur treatment. The second hardened opening layer 67 bof the second link 33 has a second pin hardness of 1000 Hv or more and 3500 Hv or less.The first pin 37 is made of a metal. The first pin 37 has the first pin radially outward surface 37 awith respect to the first outer link center axis X 11 and the first hardened pin layer 37 bformed on the first pin radially outward surface 37 a. Specifically, the first pin 37 is formed in a substantially tubular shape.The first pin radially outward surface 37 acorresponds to the outer circumferential surface of the first pin 37. the first hardened pin layer 37 bis formed on the outer circumferential surface of the first pin 37. In the assembled state of the half link chain 215, the first pin surface 37 afacing radially outward is configured to slide on a first adjacent inner link opening surface 63Na of the first adjacent inner link opening 63N and on a second adjacent inner link opening surface 67Na of a second adjacent inner link opening 67N. Specifically, the first hardened pin layer 37 bslides on the second hardened opening layer 63Nb of the first adjacent inner link opening surface 63Na in the first adjacent inner link opening 63N and on the second hardened opening layer 67Nb of the second adjacent inner link opening surface 67Na in the second adjacent inner link opening 67N.The first hardened pin layer 37 bof the first pin 37 is formed by any one of the following treatments: vanadium treatment, chromium treatment, boron treatment, nitriding treatment, and nitriding-sulfur treatment. The vanadium treatment, the chromium treatment, the boron treatment, the nitriding treatment, and the nitriding sulfur treatment are performed as in the third embodiment. The first hardened pin layer 37 bof the first pin 37 has a first pin hardness of greater than or equal to 1000 Hv and less than or equal to 3500 Hv.The second pin 39 is made of a metal. The second pin 39 has the second radially outward pin surface 39 aand the second hardened pin layer 39 b. Specifically, the second pin 39 is formed in a substantially tubular shape. The second pin radially outward surface 39 acorresponds to the outer circumferential surface of the second pin 39. the second hardened pin layer 39 bof the second pin 39 is formed on the outer circumferential surface of the second pin 39.The second hardened pin layer 39 bof the second pin 39 is formed by any one of the following treatments: vanadium treatment, chromium treatment, boron treatment, nitriding treatment, and nitriding-sulfur treatment. The second hardened pin layer 39 bof the second pin 39 has a first pin hardness equal to or higher than 1000 Hv and equal to or lower than 3500 Hv.The configurations of a fourth embodiment are the same as the configurations of the first embodiment except for the configurations of the half link chain 15 of the first embodiment. Therefore, in the fourth embodiment, a configuration different from that of the first embodiment is described in the half link chain 15 according to the first embodiment.In the fourth embodiment, configurations that are the same as or similar to those of the first embodiment are denoted by the same reference numerals. In the fourth embodiment, the description of the configuration identical or similar to that of the first embodiment may be omitted. In this case, the description of the configuration omitted in the fourth embodiment is based on the description of the first embodiment.As illustrated in FIGS. 2 to 5, a half link chain 415 for the bicycle 1 includes the first link 31 including the first outer link portion 43 having the first outer link opening 61 with the first outer link center axis X 11, the first inner link portion 45 having the first inner link opening 63 with the first inner link center axis X 12, the first axially outward facing surface 47 with respect to an axial direction AD defined by the first outer link center axis X 11 and the first inner link center axis X 12, and the first axially inward facing surface 49 opposite to the first axially outward facing surface 47 with respect to the axial direction AD. The half link chain 415 for the bicycle 1 further includes the second link 33 including the second outer link portion 51 having the second outer link opening 65 with the second outer link center axis X 21, the second inner link portion 53 having the second inner link opening 67 with the second inner link center axis X 22, the second axially outward facing surface 55 with respect to the axial direction AD, and the second axially inward facing surface 57 that is opposed to the second axially outward facing surface 55 with respect to the axial direction AD and configured to face the first axially inward facing surface 49 in the axial direction AD in an assembled state of the half link chain 415. The half link chain 415 for the bicycle 1 further includes at least one pin 36 having at least one pin cavity 93 and configured to be inserted into the first outer link opening 61 of the first link 31 and the second outer link opening 65 of the second link 33 in the assembled state of the half link chain 415 or to be inserted into the first inner link opening 63 of the first link 31 and the second inner link opening 67 of the second link 33 in the assembled state of the half link chain 415.As illustrated in FIGS. 2 to 5, in the assembled state of the half link chain 415, the second outer link center axis X 21 is formed to be coaxial with the first outer link center axis X 11. In the assembled state of the half link chain 415, the second inner link center axis X 22 is configured to be coaxial with the first inner link center axis X 12.As shown in FIGS. 2 to 5, the first outer member portion 43 and the first inner member portion 45 are at least partially offset from each other in the axial direction AD, so that the first outer member opening 61 and the first inner member opening 63 are offset from each other in the axial direction AD. The second outer member portion 51 and the second inner member portion 53 are at least partially offset from each other in the axial direction AD, so that the second outer member opening 65 and the second inner member opening 67 are offset from each other in the axial direction AD.In the fourth embodiment, the configurations of the first link 31, the second link 33, the sleeve 35, the roller 41, and the tooth engagement slot 81 are the same as in the first embodiment.As shown in FIGS. 3 to 5, at least one pin 36 has at least one pin cavity 93. the at least one pin 36 includes the first pin 37 and the second pin 39. the at least one pin cavity 93 includes a first pin cavity 37 cand a second pin cavity 39 c.Specifically, the first pin 37 is formed in a substantially tubular shape. The first pin 37 has the first pin cavity 37c. The first pin cavity 37 cis defined by the inner surface of the first pin 37. The second pin 39 is formed in a substantially tubular shape. The first pin 37 is configured to be inserted into the first outer link opening 61 of the first chain link 31 and the second outer link opening 65 of the second chain link 33 in the assembled state of the half link chain 415. The second pin 39 is configured to be inserted into the first inner link opening 63 of the first link 31 and the second inner link opening 67 of the second link 33 in the assembled state of the half link chain 415. Further, the second pin 39 is configured to be inserted into the bushing cavity 71 of the bushing 35 in the assembled state of the half link chain 415.The second pin 39 has the second pin cavity 39c. The second pin cavity 39 cis defined by the inner surface of the second pin 39.In the present embodiment, the example in which the first pin 37 and the second pin 39 include the first pin cavity 37 cand the second pin cavity 39 c, respectively, has been described. The second pin 39 may be formed in a substantially cylindrical shape, and only the first pin 37 may have the first pin cavity 37 c. The first pin 37 may be formed in a substantially cylindrical shape, and only the second pin 39 may have the second pin cavity 39 c.The configurations of a fifth embodiment are the same as the configurations of the first embodiment except for the configurations of the half link chain 15 according to the first embodiment. Therefore, in the fifth embodiment, a configuration different from that of the first embodiment is described in the half link chain 15 of the first embodiment.In the fifth embodiment, configurations that are the same as or similar to those of the first embodiment are denoted by the same reference numerals. In the fifth embodiment, the description of a configuration identical or similar to that of the first embodiment may be omitted. In this case, the description of the omitted configuration in the fifth embodiment is based on the description in the first embodiment.As illustrated in FIGS. 2 to 5, a half link chain 515 for the bicycle 1 includes the first link 31 including the first outer link portion 43 having the first outer link opening 61 with the first outer link center axis X 11, the first inner link portion 45 having the first inner link opening 63 with the first inner link center axis X 12, the first axially outward facing surface 47 with respect to an axial direction AD defined by the first outer link center axis X 11 and the first inner link center axis X 12, and the first axially inward facing surface 49 opposite to the first axially outward facing surface 47 with respect to the axial direction AD. The half link chain 515 for the bicycle 1 further includes the second link 33 including the second outer link portion 51 having the second outer link opening 65 with the second outer link center axis X 21, the second inner link portion 53 having the second inner link opening 67 with the second inner link center axis X 22, the second axially outward facing surface 55 with respect to the axial direction AD, and the second axially inward facing surface 57 that is opposed to the second axially outward facing surface 55 with respect to the axial direction AD and configured to face the first axially inward facing surface 49 in the axial direction AD in an assembled state of the half link chain 515. The half link chain 515 for the bicycle 1 further includes the bushing 35 configured to be inserted into the first inner link opening 63 and the second inner link opening 67 in the assembled state of the half link chain 515 and having a bushing inner surface 35 adefining the bushing cavity 71, the first pin 37 configured to be inserted into the first outer link opening 61 of the first link 31 and the second outer link opening 65 of the second link 33 in the assembled state of the half link chain 515. The half link chain 515 for the bicycle 1 further includes the second pin 39 configured to be inserted into the first inner link opening 63 of the first link 31, the second inner link opening 67 of the second link 33, and the sleeve cavity 71 of the sleeve 35 in the assembled state of the half link chain 515, and configured to slide on the sleeve inner surface 35 aof the sleeve 35.As illustrated in FIGS. 2 to 5, in the assembled state of the half link chain 515, the second outer link center axis X 21 is formed to be coaxial with the first outer link center axis X 11. In the assembled state of the half link chain 515, the second inner link center axis X 22 is configured to be coaxial with the first inner link center axis X 12.As shown in FIGS. 2 to 5, the first outer member portion 43 and the first inner member portion 45 are at least partially offset from each other in the axial direction AD, so that the first outer member opening 61 and the first inner member opening 63 are offset from each other in the axial direction AD. The second outer member portion 51 and the second inner member portion 53 are at least partially offset from each other in the axial direction AD, so that the second outer member opening 65 and the second inner member opening 67 are offset from each other in the axial direction AD.As illustrated in FIGS. 2 to 5, in the assembled state of the half link chain 515, the sleeve 35 has the first sleeve end 73 and the second sleeve end 75 that is opposite to the first sleeve end 73 in the axial direction AD. In the assembled state of the half link chain 515, the first sleeve end 73 is configured to be disposed in the first inner link opening 63 of the first link 31. In the assembled state of the half link chain 515, the second sleeve end 75 is configured to be disposed in the second inner link opening 67 of the second link 33.As illustrated in FIG. 5, in the assembled state of the half link chain 515, the tooth engagement slot 81 is formed between the first link 31 and the second link 33 with respect to the axial direction AD. The tooth engaging slot 81 has an axially narrow portion 83 and an axially wide portion 85.The axially narrow portion 83 has a first longitudinal slot length LX 1 defined in a longitudinal direction LD of the half link chain 515. The axially wide portion 85 has a second longitudinal slot length LX2 defined in the longitudinal direction LD of the half link chain 515. One of the first longitudinal slot length LX 1 and the second longitudinal slot length LX 2 is greater than twice the other of the first longitudinal slot length LX 1 and the second longitudinal slot length LX 2.A corresponding one of the axially narrow portion 83 and the axially wide portion 85 with respect to one of the first longitudinal slot length LX 1 and the second longitudinal slot length LX 2 is configured to receive a sprocket tooth S of a sprocket during operation of the half link chain 515.In the fifth embodiment, the configurations of the first link 31, the second link 33, the sleeve 35, the first pin 37, the second pin 39, the roller 41, and the tooth engagement slot 81 are the same as in the first embodiment.As illustrated in FIG. 5, one of the first longitudinal slit length LX 1 of the axially narrow portion 83 and the second longitudinal slit length LX 2 of the axially wide portion 85 is greater than three times the other of the first longitudinal slit length LX 1 and the second longitudinal slit length LX 2. Specifically, one of the first longitudinal slit length LX 1 of the axially narrow portion 83 and the second longitudinal slit length LX 2 of the axially wide portion 85 is greater than twice the other of the first longitudinal slit length LX 1 and the second longitudinal slit length LX 2.Specifically, as illustrated in FIG. 5, the first longitudinal slot length LX 1 of the axially narrow portion 83 corresponds to a length of the axially narrow portion 83 in the longitudinal direction LD between a pair of adjacent rollers 41 and 41N. The second longitudinal slot length LX 2 of the axially wide portion 85 corresponds to a length of the axially wide portion 85 in the longitudinal direction LD between the pair of adjacent rollers 41 and 41N.The first longitudinal slot length LX 1 of the axially narrow portion 83 is greater than twice the second longitudinal slot length LX 2 of the axially wide portion 85. in particular, the first longitudinal slot length LX 1 of the axially narrow portion 83 is greater than three times the second longitudinal slot length LX 2 of the axially wide portion 85.In the assembled state of the half link chain 515, one of the axially narrow portion 83 and the axially wide portion 85 has an axial slot length LY with respect to the axial direction AD. In the present embodiment, the axial slot length LY is defined by an axial distance between the first axially inward facing surface 49 of the first inner link portion 45 and the second axially inward facing surface 57 of the second inner link portion 53. The axial slot length LY is greater than or equal to the axial chain engagement width SW of the sprocket tooth S. Specifically, a ratio of the axial slot length LY to the axial chain engagement width SW of the sprocket tooth S in the sprocket is greater than or equal to 1.0 and less than or equal to 1.2.As illustrated in FIG. 5, the first outer link portion 43 of the first link 31 has a first outer link axial thickness TO 1 with respect to the axial direction AD. The first inner link portion 45 of the first link 31 has a first inner link axial thickness TI 1 with respect to the axial direction.The first outer member axial thickness TO 1 is preferably determined at a portion of the first outer member portion 43 having the smallest axial plate thickness. The first inner-link axial thickness TI 1 is preferably determined at a portion of the first inner-link portion 45 having the smallest axial plate thickness. A first thickness difference between the first outer-link axial thickness TO 1 and the first inner-link axial thickness TI 1 (=|TO 1-TI 1|) is equal to or less than 0.2 mm. In the present embodiment, the first outer-link axial thickness TO 1 is larger than the first inner-link axial thickness TI 1.As illustrated in FIG. 5, the second outer link portion 51 of the second link 33 has a second outer link axial thickness TO 2 with respect to the axial direction AD. The second inner link portion 53 of the second link 33 has a second inner link axial thickness TI 2 with respect to the axial direction AD.The second outer-member axial thickness TO 2 is preferably determined at a portion of the second outer-member portion 51 having the smallest axial plate thickness. The second inner-link axial thickness TI 2 is preferably determined at a portion of the second inner-link portion 53 having the smallest axial plate thickness. A second thickness difference between the second outer-link axial thickness TO 2 and the second inner-link axial thickness TI 2 (=|TO 2-TI 2|) is equal to or less than 0.2 mm. In the present embodiment, the second outer-member axial thickness TO 2 is larger than the second inner-member axial thickness TI 2.Although each embodiment of the present invention has been described above, the present invention is not limited to the first to fifth embodiments, and various modifications may be made without departing from the scope of the invention. In particular, a plurality of embodiments and modified examples described in the present specification can be freely selected and combined as necessary.The phrase "at least one(s)" as used in this specification means "one or more" of the desired options. In a case where the number of options is two, the term "at least one(r / s)" as used in this specification means, for example, "only one option" or "both of the two options". As another example, in a case where the number of options is three or more, the term "at least one(s)" as used in this specification means "only one option" or "any combination of two or more options.".The term "formed to be coaxial" as used in this specification means that the constituent elements of the half link chain are coaxial with each other in a case where the constituent elements of the half link chain are arranged at ideal positions in the assembled state of the half link chain. Therefore, the term "formed to be coaxial" also includes a structure in which a coaxial position is deviated due to play or the like between the constituent members of the half link chain during use of the half link chain as long as the constituent members are coaxial with each other in the case where the constituent members are arranged at the ideal positions in the assembled state of the half link chain.REFERENCE NUMERALS1 Bicycle, human-powered vehicle 3 Frame 5 Handlebar 7 Front wheel 7 a Vorderer 9 Rear wheel 9 a Hinter 11 Gear shift 13 Driving portion 15, 115, 215, 315, 415, 515 half link chain 17 front fork 18 derailleur 19 derailleur 20 rear hub assembly 21 rear sprocket assembly 22 crank assembly 23 crank arm 24 front sprocket assembly 31 first link 31N first adjacent link 32 first axially protruding portion 33 second link 33N second adjacent link 34 second axially protruding portion 35 sleeve 35a sleeve inner surface 35N adjacent sleeve 36 at least one pin 37a first radially outward facing pin surface 37b first hardened pin layer 37c first pin cavity 37 first pin 37N first pin of the adjacent unit 39 second pin 39a second radially outward facing pin surface 39b second hardened pin layer 39c second pin cavity 39N second pin of the adjacent unit 41 roller 41N adjacent roller 43 first outer link portion 45 first inner link portion 47 first axially outward facing surface 49 first axially inward facing surface 50 first outer peripheral surface 51 second outer link portion 53 second inner link portion 55 second axially outward facing surface 57 second axially inward facing surface 61 first outer link opening 61N first adjacent outer link opening 63 first inner link opening 63 afirst inner link opening surface 63 bfirst hardened opening layer 63Na first adjacent inner link opening surface 63Nb second hardened opening layer 65 second outer link opening 65N second adjacent outer link opening 67 second inner link opening 67N second adjacent inner link opening 67 asecond inner link opening surface 67 bsecond hardened opening layer 67Na second adjacent inner link opening surface 67Nb second hardened opening layer 71 sleeve cavity 71N adjacent sleeve cavity 73 first sleeve end 75 second sleeve end 77 first pin end 78 second pin end 79 third pin end 80 fourth pin end 81 Tooth engaging slot 83 Axially narrow portion 85 Axially wide portion 87, 87A, 87B First chamfered portion 88 Second outer circumferential surface 89, 89A, 89B Second chamfered portion 91 Hardened sleeve layer 93 At least one pin cavity AD Axial direction LD Longitudinal direction LX 1 First longitudinal slot length LX 2 Second longitudinal slot length LY Axial slot length S Sprocket tooth SW Axial chain engaging width TO 1 First outer link axial thickness TI 1 First inner link axial thickness TO 2 Second outer link axial thickness TI 2 Second inner link axial thickness W 1 Axial distance W 2 Axial distance X 11 First outer link central axis X 12 First inner link central axis X 21 Second outer link central axis X 22 Second inner link central axisReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedEP 303 21 39 A1 [0003, 0004]

Claims

A half link chain (15, 115, 215, 315, 415, 515) for a human-powered vehicle (1) comprising: a first link (31) including a first outer link portion (43) and a first inner link portion (45), the first outer link portion (43) having a first outer link opening (61) with a first outer link center axis (X11), the first inner link portion (45) having a first inner link opening (63) with a first inner link center axis (X12), the first outer link center axis (X11) and the first inner link center axis (X12) defining an axial direction (AD), the first outer link portion (43) and the first inner link portion (45) being at least partially offset from each other in the axial direction (AD), such that the first outer link opening (61) and the first inner link opening (63) are offset from each other in the axial direction (AD), the first link (31) having a first axially outward facing surface (47) with respect to the axial direction (AD) and a first axially inward facing surface (49) opposite the first axially outward facing surface (47) with respect to the axial direction (AD); a second link (33) including a second outer link portion (51) and a second inner link portion (53), the second outer link portion (51) having a second outer link opening (65) with a second outer link central axis (X21), wherein the second inner link portion (53) has a second inner link opening (67) having a second inner link center axis (X22), wherein the second outer link center axis (X21) is configured to be coaxial with the first outer link center axis (X11) in an assembled state of the half link chain (15, 115, 215, 315, 415, 515), wherein the second inner link center axis (X22) is configured to be coaxial with the first inner link center axis (X12) in the assembled state, wherein the second outer link portion (51) and the second inner link portion (53) are at least partially offset from one another in the axial direction (AD), such that the second outer link opening (65) and the second inner link opening (67) are offset from one another in the axial direction (AD), wherein the second chain link (33) has a second axially outward-facing surface (55) with respect to the axial direction (AD) and a second axially inward-facing surface (57) opposite the second axially outward-facing surface (55) with respect to the axial direction (AD), wherein the second axially inward-facing surface (57) of the second chain link (33) is configured to face the first axially inward-facing surface (49) of the first chain link (31) in the axial direction (AD) in the assembled state, wherein the second chain link (33) is a separate element from the first chain link (31); a sleeve (35) configured to be inserted into the first inner link opening (63) and the second inner link opening (67) in the assembled state, the sleeve (35) having a sleeve cavity (71) defined by a sleeve inner surface (35a) of the sleeve (35), a first sleeve end (73) and a second sleeve end (75) opposite to the first sleeve end (73) with respect to the axial direction (AD) in the assembled state, the first sleeve end (73) configured to be disposed in the first inner link opening (63) of the first link (31) in the assembled state, the second sleeve end (75) configured to be disposed in the second inner link opening (67) of the second link (33) in the assembled state; a first pin (37) configured to be inserted into the first outer link opening (61) of the first link (31) and the second outer link opening (65) of the second link (33) in the assembled state of the half link chain (15, 115, 215, 315, 415, 515); and a second pin (39) configured to be inserted into the first inner link opening (63) of the first link (31), the second inner link opening (67) of the second link (33) and the sleeve cavity (71) of the sleeve (35) in the assembled state, the second pin (39) configured to slide on the sleeve inner surface (35a) of the sleeve (35), a tooth engagement slot (81), which is formed between the first link (31) and the second link (33) in the assembled state with respect to the axial direction (AD), wherein the tooth engaging slot (81) has an axially narrow portion (83) and an axially wide portion (85) in the axial direction (AD), wherein the axially narrow portion (83) has a first longitudinal slot length (LX1) defined in a longitudinal direction of the half link chain (15, 115, 215, 315, 415, 515), wherein the axially wide portion (85) has a second longitudinal slot length (LX2) defined in the longitudinal direction, wherein one of the first longitudinal slot length (LX1) and the second longitudinal slot length (LX2) is greater than twice the other of the first longitudinal slot length (LX1) of the axially narrow portion (83) and the second longitudinal slot length (LX2) of the axially wide portion (85), a corresponding one of the axially narrow portion (83) and the axially wide portion (85) being formed with respect to the one of the first longitudinal slot length (LX1) and the second longitudinal slot length (LX2) to receive a sprocket tooth (S) of a sprocket during operation of the half link chain (15, 115, 215, 315, 415, 515).The half link chain (15, 115, 215, 315, 415, 515) according to claim 1, wherein the one of the first longitudinal slot length (LX1) of the axially narrow portion (83) and the second longitudinal slot length (LX2) of the axially wide portion (85) is greater than three times the other of the first longitudinal slot length (LX1) of the axially narrow portion (83) and the second longitudinal slot length (LX2) of the axially wide portion (85).The half link chain (15, 115, 215, 315, 415, 515) according to claim 1 or 2, wherein the first longitudinal slot length (LX1) of the axially narrow portion (83) is greater than twice the second longitudinal slot length (LX2) of the axially wide portion (85).The half link chain (15, 115, 215, 315, 415, 515) according to claim 3, wherein the first longitudinal slot length (LX1) of the axially narrow portion (83) is greater than three times the second longitudinal slot length (LX2) of the axially wide portion (85).The half link chain (15, 115, 215, 315, 415, 515) according to any one of claims 1 to 4, wherein the corresponding one of the axially narrow portion (83) and the axially wide portion (85) has an axial slot length (LY) in the assembled state with respect to the axial direction (AD), and a ratio of the axial slot length (LY) to an axial chain engagement width (SW) of the sprocket tooth (S) of the sprocket is equal to or greater than 1.0 and equal to or less than 1.2.The half link chain (15, 115, 215, 315, 415, 515) according to any one of claims 1 to 5, wherein the first pin (37) has a first pin end (77) and a second pin end (78) opposing the first pin end (77) with respect to the axial direction (AD) in the assembled state, the second pin (39) has a third pin end (79) and a fourth pin end (80) opposing the third pin end (79) with respect to the axial direction (AD) in the assembled state, the first pin (37) is fixed to the first link (31) by upsetting the first pin end (77) of the first pin (37), the first pin (37) is fastened to the second chain link (33) by upsetting the second pin end (78) of the first pin (37), the second pin (39) is fastened to a first adjacent chain link (31N) by upsetting the third pin end (79) of the second pin (39), and the second pin (39) is fastened to a second adjacent chain link (33N) by upsetting the fourth pin end (80) of the second pin (39).The half link chain (15, 115, 215, 315, 415, 515) according to any one of claims 1 to 6, further comprising: a roller (41) configured to be disposed around the sleeve (35) in the assembled state and between the first link (31) and the second link (33) with respect to the axial direction (AD).The half link chain (15, 115, 215, 315, 415, 515) according to any one of claims 1 to 7, wherein the axially narrow portion (83) is formed at least between the first inner link portion (45) of the first link (31) and the second inner link portion (53) of the second link (33) in the axial direction (AD), and the axially wide portion (85) is formed at least between the first outer link portion (43) of the first link (31) and the second outer link portion (51) of the second link (33) in the axial direction (AD).The half link chain (15, 115, 215, 315, 415, 515) according to any one of claims 1 to 8, wherein the first outer link portion (43) of the first link (31) has a first outer link axial thickness (TO1) defined in the axial direction (AD), the first inner link portion (45) of the first link (31) has a first inner link axial thickness (TI1) defined in the axial direction (AD), and a first thickness difference between the first outer link axial thickness (TO1) and the first inner link axial thickness (TI1) is equal to or less than 0.2 mm.The half link chain (15, 115, 215, 315, 415, 515) according to any one of claims 1 to 9, wherein the second outer link portion (51) of the second link (33) has a second outer link axial thickness (TO2) defined in the axial direction (AD), the second inner link portion (53) of the second link (33) has a second inner link axial thickness (TI2) defined in the axial direction (AD), and a second thickness difference between the second outer link axial thickness (TO2) and the second inner link axial thickness (TI2) is equal to or less than 0.2 mm.

Images