TWI851562B - Human-powered vehicle sprocket - Google Patents

Abstract

[Topic] To provide a sprocket for a human-powered vehicle that can improve the holding force of the chain. [Solution] The human-powered vehicle sprocket is a human-powered vehicle sprocket that rotates around a rotation center axis, and comprises: a sprocket body, and a plurality of sprocket teeth arranged around the outer periphery of the sprocket body; the plurality of sprocket teeth include: at least one first tooth having a first maximum chain engagement axial width relative to the rotation center axis, and at least one second tooth having a first maximum chain engagement axial width relative to the rotation center axis. The rotation center axis has at least one second tooth with a second maximum chain engagement axial width; the first maximum chain engagement axial width is greater than the second maximum chain engagement axial width in the axial direction relative to the rotation center axis, and the at least one first tooth has the first maximum chain engagement axial width. The at least one axial protrusion is a single integral component of the at least one first tooth, and includes: at least one axial protrusion formed as a whole with the at least one first tooth; the at least one axial protrusion has: a radial outermost end and a radial innermost end relative to the rotation center axis; the radial innermost end of the at least one axial protrusion is arranged closer to the radial inner side than the tooth root of the at least one first tooth; the at least one axial protrusion has an inclined portion extending from the radial innermost end toward the radial outer side; the inclined portion of the at least one axial protrusion is inclined relative to the first axial tooth center plane that divides the at least one first tooth into two equal parts in the axial direction.

Description

Human-powered vehicle sprocket

The present invention relates to a sprocket for a human-powered vehicle.

For example, a human-powered vehicle includes a sprocket engaged with a chain.

An object of the present invention is to provide a sprocket for a human-powered vehicle that can enhance the holding force of the chain.

The first type of human-driven vehicle sprocket of the present invention is a human-driven vehicle sprocket that rotates around a rotation center axis and comprises: a sprocket body, and a plurality of sprocket teeth arranged around the outer periphery of the sprocket body; the plurality of sprocket teeth include: at least one sprocket having a first maximum chain engagement axial width relative to the rotation center axis. The first tooth and at least one second tooth having a second maximum chain engagement axial width relative to the rotation center axis; the first maximum chain engagement axial width is greater than the second maximum chain engagement axial width in the axial direction relative to the rotation center axis, and the at least one first tooth, as having the first maximum chain engagement axial width The single integral component of the axial width includes: at least one axial protrusion formed as a whole with the at least one first tooth; the at least one axial protrusion has: a radial outermost end and a radial innermost end relative to the rotation center axis; the radial innermost end of the at least one axial protrusion is arranged closer to the radial inner side than the tooth root of the at least one first tooth; the at least one axial protrusion has an inclined portion extending from the radial innermost end toward the radial outer side; the inclined portion of the at least one axial protrusion is inclined relative to the first axial tooth center plane that divides the at least one first tooth into two equal parts in the axial direction. With the sprocket of the first type, the first maximum chain engagement axial width of at least one first tooth and the second maximum chain engagement axial width of at least one second tooth can be respectively made into widths suitable for engagement with the sprocket. Therefore, the holding force of the chain can be improved. With the sprocket of the first type, the radial innermost end of at least one axially raised portion is arranged closer to the radial inner side than the tooth root of at least one first tooth, so the rigidity of the first tooth can be improved.

According to the second type of sprocket of the first type, the inclined portion of the at least one axially raised portion extends from the radial innermost end portion toward the radial outer side beyond the tooth root of the at least one first tooth in the radial direction relative to the rotation center axis. With the second type of sprocket, the inclined portion includes a portion corresponding to the tooth root, so that the weight of the sprocket can be suppressed from increasing.

According to the third type of sprocket of the first or second type, the first maximum chain engagement axial width is greater than: the inner connecting rod axial space defined by a pair of inner connecting rod pieces facing each other in the chain of the human-driven vehicle in the above-mentioned axial direction, and less than: the outer connecting rod axial space defined by a pair of outer connecting rod pieces facing each other in the chain of the human-driven vehicle in the above-mentioned axial direction; the second maximum chain engagement axial width is less than the inner connecting rod axial space.

The chain can be effectively held by the third type of sprocket mentioned above.

According to the 4th type of sprocket of the 3rd type, the 1st maximum chain engagement axis direction width of the at least one 1st tooth is more than 75% of the space in the axis direction of the outer connecting rod.

The chain can be held more effectively by the sprocket of the fourth type mentioned above.

According to the 5th type of sprocket of any one of the 1st to 4th types, the first radial length is defined as the distance between the first radial outermost tooth end of the at least one first tooth in the radial direction relative to the rotation center axis and the rotation center axis; the second radial length is defined as the distance between the second radial outermost tooth end of the at least one second tooth in the radial direction relative to the rotation center axis and the rotation center axis; the first radial length is greater than the second radial length.

With the sprocket of the fifth type, when at least one first tooth is engaged with the chain, it is engaged with the chain earlier than when at least one second tooth is engaged with the chain, so the chain can be effectively held.

According to the 6th type of sprocket of any one of the 1st to 5th types, the at least one first tooth has, in the axial direction relative to the rotation center axis, a first axial tooth center line offset from the first axial tooth center plane of the at least one first tooth.

With the sprocket of the sixth type, since the first axial tooth centerline of at least one first tooth is offset from the first axial tooth center plane of at least one first tooth, the chain can be effectively held even when the chain is tilted in the axial direction between the front sprocket and the rear sprocket.

According to the sprocket of the seventh type of any one of the above-mentioned types 1 to 6, the at least one second tooth has: a second axial tooth center line offset from a second axial tooth center plane that bisects the at least one second tooth in the above-mentioned axial direction.

With the sprocket of the seventh type, since the second axial tooth centerline of the second tooth is offset from the second axial tooth center plane of at least one second tooth, the chain can be effectively held even when the chain is tilted in the axial direction between the front sprocket and the rear sprocket.

According to the 8th type of sprocket of any one of the 1st to 7th types, the at least one first tooth is asymmetrical with respect to the first circumferential tooth root center line in the circumferential direction relative to the rotation center axis.

By using the sprocket of the eighth type, the degree of freedom in the design of at least one first tooth in the circumferential direction relative to the rotation center axis can be increased.

According to the 9th type of sprocket of any one of the 1st to 7th types, the at least one first tooth is symmetrical with respect to the first circumferential tooth root center line in the circumferential direction relative to the rotation center axis.

By using the sprocket of the 9th type mentioned above, the sprocket can be turned over relative to at least one first tooth.

According to the sprocket of the tenth type of any one of the first to fifth types, the at least one first tooth is asymmetrical with respect to the tooth center plane in the first axial direction relative to the rotation center axis. The sprocket of the tenth type can improve the degree of freedom of design of the at least one first tooth in the axial direction relative to the rotation center axis.

According to the 11th type of sprocket of any one of the 1st to 10th types, the at least one first tooth is symmetrical with respect to the center plane of the tooth in the first axial direction in the axial direction relative to the rotation center axis. The 11th type of sprocket can effectively hold the chain by the at least one first tooth.

According to the 12th type of sprocket of any one of the 1st to 11th types, the at least one second tooth is asymmetrical relative to the second circumferential direction tooth root center line in the circumferential direction relative to the rotation center axis. The 12th type of sprocket can improve the degree of freedom of design of the at least one second tooth in the circumferential direction relative to the rotation center axis.

According to the 13th type of sprocket of any one of the 1st to 12th types, the at least one second tooth is symmetrical with respect to the center line of the tooth root in the second circumferential direction in the circumferential direction relative to the rotation center axis. With the 13th type of sprocket, the sprocket can be flipped for use relative to the at least one second tooth.

According to the sprocket of the 14th type of any one of the 1st to 13th types, the at least one second tooth is asymmetric in the axial direction relative to the rotation center axis with respect to the second axial direction tooth center plane that bisects the at least one second tooth in the axial direction. The sprocket of the 14th type can improve the degree of freedom of design of the at least one second tooth in the axial direction relative to the rotation center axis.

According to the sprocket of the 15th type of any one of the 1st to 6th types, the at least one second tooth is symmetrical in the axial direction relative to the rotation center axis and relative to the second axial direction tooth center plane that divides the at least one second tooth in the axial direction into two equal parts. The sprocket of the 15th type can effectively hold the chain by the at least one second tooth.

According to the sprocket of the 16th type of any one of the 1st to 15th types, the at least one first tooth includes a plurality of first teeth, the at least one second tooth includes a plurality of second teeth, and the plurality of first teeth and the plurality of second teeth are alternately arranged in the circumferential direction relative to the rotation center axis. With the sprocket of the 16th type, the chain can be effectively held by the plurality of first teeth and the plurality of second teeth.

The sprocket of the 17th type of the present invention is a sprocket for a human-driven vehicle that rotates around a rotation center axis, and comprises: a sprocket body, and a plurality of sprocket teeth arranged around the outer periphery of the sprocket body; the plurality of sprocket teeth include: at least one first tooth having a first maximum chain engagement axis width relative to the rotation center axis, at least one second tooth having a second maximum chain engagement axis width relative to the rotation center axis, a second tooth; the first maximum chain engagement axial width is greater than the second maximum chain engagement axial width in the axial direction relative to the rotation center axis, the at least one first tooth includes a first driving surface, the first driving surface is provided with: a first predetermined chain roller contact point for defining the pitch circle diameter of the sprocket for the human-powered vehicle; the at least one second tooth includes a second driving surface, the second ... The mask is provided with: a second predetermined chain roller contact point for defining the pitch circle diameter of the sprocket for the human-powered vehicle; a first tangent line, relative to the first driving surface, defined at the first predetermined chain roller contact point, a second tangent line, relative to the second driving surface, defined at the second predetermined chain roller contact point; a first reference line, defined as passing through the rotation center axis and the first predetermined chain roller contact point, a second reference line The first vertex angle is defined as passing through the rotation center axis and the second predetermined chain roller contact point; the first vertex angle is defined between the first tangent line and the first baseline in the radial direction inward from the first predetermined chain roller contact point; the second vertex angle is defined between the second tangent line and the second baseline in the radial direction inward from the second predetermined chain roller contact point; the first vertex angle is different from the second vertex angle. With the sprocket of the 17th embodiment, the first maximum chain engagement axial width of at least one first tooth and the second maximum chain engagement axial width of at least one second tooth can be respectively made into widths suitable for engagement with the sprocket. Therefore, the holding force of the chain can be improved. With the sprocket of the 17th embodiment, the tooth surface of at least one first tooth and the tooth surface of at least one second tooth can be respectively made into appropriate shapes.

According to the sprocket of the 18th type of the sprocket of the 17th type, the first top angle is greater than the second top angle. The sprocket of the 18th type can reduce the stress of the tooth root of at least one first tooth. Therefore, the wear of at least one first tooth can be suppressed.

According to the sprocket of the 19th type of the 17th type, the first top angle is smaller than the second top angle. The sprocket of the 19th type can reduce the stress of the tooth root of at least one second tooth. Therefore, the wear of at least one second tooth can be suppressed.

According to the 20th type of sprocket of any one of the 17th to 19th types, the difference between the first vertex angle and the second vertex angle is 3 degrees or more. By using the 20th type of sprocket, the difference between the first vertex angle and the second vertex angle can be maintained within an appropriate range.

According to the 21st type of sprocket of any one of the 17th to 20th types, the difference between the first vertex angle and the second vertex angle is less than 7 degrees. By using the 21st type of sprocket, the difference between the first vertex angle and the second vertex angle can be maintained within an appropriate range.

According to the 22nd type of sprocket of any one of the 17th to 21st types, the first maximum chain engagement axial width is greater than: the inner connecting rod axial space defined by a pair of inner connecting rod pieces facing each other in the above-mentioned axial direction of the chain of the human-driven vehicle, and less than: the outer connecting rod axial space defined by a pair of outer connecting rod pieces facing each other in the above-mentioned axial direction of the chain of the human-driven vehicle; the second maximum chain engagement axial width is less than the inner connecting rod axial space. The 22nd type of sprocket can effectively hold the chain.

The 23rd type of human-driven vehicle sprocket of the present invention is a human-driven vehicle sprocket that rotates around a rotation center axis, and comprises: a sprocket body, and a plurality of sprocket teeth arranged around the outer periphery of the sprocket body; the plurality of sprocket teeth include: at least one first tooth having a first maximum chain engagement axial width relative to the rotation center axis, and at least one second maximum chain engagement axial width relative to the rotation center axis. At least one second tooth having a maximum chain engagement axial width relative to the rotation center axis, and at least one third tooth having a third maximum chain engagement axial width relative to the rotation center axis; the first maximum chain engagement axial width and the third maximum chain engagement axial width are respectively greater than the second maximum chain engagement axial width in the axial direction relative to the rotation center axis, and the at least one first tooth includes: having The at least one axial ridge of the first maximum chain engagement axial width; the at least one axial ridge has: a radial outermost end and a radial innermost end relative to the rotation center axis; the radial innermost end is arranged at a radial position, the at least one third tooth has an additional axial ridge, and the additional axial ridge has a third maximum chain engagement axial width, The at least one additional axial protrusion has: an additional radial outermost end and an additional radial innermost end relative to the rotation center axis; the additional radial innermost end is arranged at an additional radial position, and the radial position of the radial innermost end of the at least one axial protrusion is different from the additional radial position of the additional radial innermost end of the at least one additional axial protrusion. By means of the 23rd type of sprocket, the first maximum chain engagement axial width of at least one first tooth, the second maximum chain engagement axial width of at least one second tooth, and the third maximum chain engagement axial width of at least one third tooth can be respectively made into widths suitable for engagement with the sprocket. By means of the sprocket of the 23rd embodiment, the radial position of the radial innermost end of at least one axial protrusion and the additional radial position of the additional radial innermost end of at least one additional axial protrusion can be respectively arranged at the most appropriate positions.

According to the 24th type of sprocket of the 23rd type, the radial innermost end of the at least one axially raised portion is arranged closer to the radial inner side than the tooth root of the at least one first tooth. According to the 24th type of sprocket, the radial innermost end of the at least one axially raised portion is arranged closer to the radial inner side than the tooth root of the at least one first tooth, so the rigidity of the first tooth can be improved.

According to the 25th type of sprocket of the 24th type, the radial innermost end of the at least one additional axially raised portion is arranged at a position closer to the radial outer side than the tooth root of the at least one third tooth, or is arranged at the same position as the tooth root of the at least one third tooth in the radial direction. With the 25th type of sprocket, foreign matter such as mud intruding near the at least one third tooth can be easily kept away from the sprocket via at least the additional radial innermost end of the additional axially raised portion.

According to the 26th type of sprocket of any one of the above 23rd to 25th types, the above first maximum chain engagement axial width is equal to the above third maximum chain engagement axial width. The 26th type of sprocket can effectively hold the chain.

According to the 27th type of sprocket of the 25th type, the outer peripheral portion of the sprocket body includes: a high-load area with a larger pedal load and a low-load area with a smaller pedal load; the at least one first tooth is arranged in the high-load area, and the at least one third tooth is arranged in the low-load area. By means of the 27th type of sprocket, the first tooth with higher rigidity can be arranged in the high-load area.

According to the 28th type of sprocket of any one of the 23rd to 27th types, the first maximum chain engagement axial width and the third maximum chain engagement axial width are respectively greater than: the inner connecting rod axial direction space defined by a pair of inner connecting rod pieces facing each other in the above-mentioned axial direction of the chain of the human-driven vehicle, and are respectively less than: the outer connecting rod axial direction space defined by a pair of outer connecting rod pieces facing each other in the above-mentioned axial direction of the chain of the human-driven vehicle; the second maximum chain engagement axial width is less than the inner connecting rod axial direction space. The 28th type of sprocket can effectively hold the chain.

The sprocket for a human-powered vehicle of the present invention can enhance the holding force of a chain.

(First embodiment) The sprocket 10 for a human-powered vehicle of the first embodiment is described with reference to FIGS. 1 to 7. A human-powered vehicle is a vehicle that can be driven at least by human power. Human-powered vehicles are not limited to the number of wheels, and include, for example, unicycles and vehicles with three or more wheels. Human-powered vehicles 10 include, for example, mountain bikes, road bikes, city bikes, cargo bikes, recumbent bikes and other types of bicycles, and electric bicycles (E-bikes). Electric bicycles include electric assisted bicycles that are propelled by an electric motor to assist the vehicle. In the following embodiments, human-powered vehicles are described as bicycles.

The sprocket 10 is a human-powered vehicle sprocket 10 that rotates around a rotation center axis CX. The sprocket 10 may be a front sprocket or a rear sprocket. In this embodiment, the sprocket 10 is referred to as a front sprocket for explanation.

The sprocket 10 includes a sprocket body 12 and a plurality of sprocket teeth 16 disposed around an outer peripheral portion 14 of the sprocket body 12. The plurality of sprocket teeth 16 include at least one first tooth 18 having a first maximum chain engagement axial width W1 relative to a rotation center axis CX, and at least one second tooth 20 having a second maximum chain engagement axial width W2 relative to the rotation center axis CX. The first maximum chain engagement axial width W1 is greater than the second maximum chain engagement axial width W2 in an axial direction DA relative to the rotation center axis CX. At least one first tooth 18, as a single integral member having a first maximum chain engagement axial width W1, includes at least one axially ridged portion 22 formed integrally with at least one first tooth 18. At least one axially ridged portion 22 has a radially outermost end 24 and a radially innermost end 26 relative to the rotation center axis CX. The radially innermost end 26 of at least one axially ridged portion 22 is arranged closer to the radially inner side B1 than the tooth root 18A of at least one first tooth 18. At least one axially ridged portion 22 has an inclined portion 28 extending from the radially innermost end 26 toward the radially outer side B2. The inclined portion 28 of at least one axial protrusion 22 is inclined relative to the first axial tooth center plane E1 that bisects at least one first tooth 18 in the axial direction DA. The first axial tooth center plane E1 bisects the first tooth 18 in the axial direction DA at the tooth root 18A of the first tooth 18. The term "tooth root 18A of the first tooth 18" herein refers to the tooth root 18A that is adjacent to the first tooth 18 as the object in one of the circumferential directions DR. Similarly, the term "tooth root 20A of the second tooth 20" refers to the tooth root 20A that is adjacent to the second tooth 20 as the object in one of the circumferential directions DR. One of the circumferential directions DR may be a direction opposite to the rotation direction of the sprocket 10 or may be the rotation direction.

The sprocket body 12 includes: an annular portion 13 having a disc shape. The annular portion 13 is preferably made of metal. In the present embodiment, the annular portion 13 has a perfect circular shape. The annular portion 13 may also have an elliptical shape. The annular portion 13 includes: an outer peripheral portion 14, and an inner peripheral portion 32 that is continuous with the outer peripheral portion 14 and is arranged closer to the radial inner side B1 than the outer peripheral portion 14. In the present embodiment, the entire inner peripheral portion 32 has a substantially uniform width W3. And in the present embodiment, the width W3 is less than the first maximum chain engagement axis direction width W1. The width W3 may also be greater than the first maximum chain engagement axis direction width W1. The width W3 may be larger than the second maximum chain engagement axial width W2. The width W3 may be smaller than the second maximum chain engagement axial width W2. In this embodiment, the peripheral portion 14 has a substantially uniform width W4. In this embodiment, the width W4 of the peripheral portion 14 is smaller than the width W3. However, the present invention is not limited to these embodiments with respect to the width W3 and the width W4.

The sprocket body 12 further includes a plurality of protrusions 32A protruding from the inner peripheral portion 32 toward the radial inner side B1. The protrusions 32A are formed integrally with the sprocket body 12. The plurality of protrusions 32A are respectively formed with holes 32B for coupling with the sprocket 10 and the crank arm or other sprockets. However, the present invention is not limited to these embodiments regarding the protrusions 32A.

The sprocket body 12 preferably further includes: a covering portion 30 covering at least a portion of the annular portion 13. The covering portion 30 and the annular portion 13 are preferably inlaid. In the present embodiment, the outermost end 30A of the covering portion 30 in the radial direction BA is located closer to the radial inner side B1 than the outermost end 14A of the outer peripheral portion 14 in the radial direction BA, and closer to the radial outer side B2 than the boundary between the inner peripheral portion 32 and the outer peripheral portion 14. In the present embodiment, the minimum width W5 in the axial direction DA of the portion provided with the covering portion 30 is greater than the width W3, greater than the first maximum chain engagement axial width W1, and greater than the second maximum chain engagement axial width W2. However, the present invention is not limited to these implementations regarding the outermost end 30A and the minimum width W5.

The at least one first tooth 18 preferably includes a plurality of first teeth 18. The at least one second tooth 20 preferably includes a plurality of second teeth 20. The plurality of first teeth 18 and the plurality of second teeth 20 are alternately arranged in the circumferential direction DR relative to the rotation center axis CX. The number of first teeth 18 is preferably equal to the number of second teeth 20. Adjacent tooth roots 18A and tooth roots 20A are arranged on the same tooth root circle RC.

At least one axial raised portion 22 is preferably provided on both sides of at least one first tooth 18 in the axial direction DA. At least one axial raised portion 22 is preferably provided on both sides of all first teeth 18 in the axial direction DA. When the sprocket 10 is a rear sprocket, the axial raised portion 22 may be provided on only one side of the first tooth 18 in the axial direction DA in order to allow the speed change action of the rear derailleur to be performed smoothly.

The inclined portion 28 of at least one axial protrusion 22 extends from the radial innermost end 26 toward the radial outer side B2 beyond the tooth root 18A of at least one first tooth 18 in the radial direction BA relative to the rotation center axis CX. The inclined portion 28 is inclined so as to get closer to the first axial tooth center plane E1 of the first tooth 18 as it moves toward the radial inner side B1.

The axially raised portion 22 further includes: a middle portion 34 and a front end portion 36. The middle portion 34 is continuous with the radially outer side B2 portion of the inclined portion 28. The front end portion 36 is continuous with the radially outer side B2 portion of the middle portion 34. The front end portion 36 is inclined so as to get closer to the first axial tooth center plane E1 of the first tooth 18 as it moves toward the radially outer side B2. The middle portion 34 has a first maximum chain engagement axial width W1. One end portion of the middle portion 34 in the circumferential direction DR is inclined so as to get closer to the first axial tooth center plane E1 of the first tooth 18 as it moves toward one side of the circumferential direction DR. The other end portion of the intermediate portion 34 in the circumferential direction DR is inclined so as to get closer to the first axial tooth center plane E1 of the first tooth 18 as it goes toward the other direction in the circumferential direction DR.

At least one first tooth 18 is preferably symmetrical with respect to the first axial tooth center plane E1 in the axial direction DA relative to the rotation center axis CX. At least one first tooth 18 has a first axial tooth end center plane F1 substantially consistent with the first axial tooth center plane E1 of at least one first tooth 18 in the axial direction DA relative to the rotation center axis CX. The first axial tooth end center plane F1 bisects the first tooth 18 in the axial direction DA at the first radial outermost tooth end 18B of the first tooth 18. At least one first tooth 18 is symmetrical with respect to the first circumferential tooth root center line G1 in the circumferential direction DR relative to the rotation center axis CX. When at least one axial raised portion 22 is provided on each of the two sides in the axial direction DA of the first tooth 18, the axial raised portion 22 may be symmetrical with respect to the first circumferential tooth root center line G1. The first circumferential tooth root center line G1 is a straight line passing through the center point 18X and the rotation center axis CX when viewed from the axial direction DA; the center point 18X is the center point 18X in the circumferential direction DR of the tooth root 18A and the tooth root 20A adjacent to the tooth root 18A on the other side in the circumferential direction DR.

The second tooth 20 includes a base end portion 38 and a front end portion 40. The base end portion 38 is continuous with the sprocket body 12. The front end portion 40 is continuous with the radially outer side B2 portion of the base end portion 38. The front end portion 40 is inclined so as to get closer to the second axial tooth center plane E2 of the second tooth 20 as it moves toward the radially outer side B2. The base end portion 38 has a second maximum chain engagement axial width W2. One end of the front end portion 40 in the circumferential direction DR is inclined so as to get closer to the second axial tooth center plane E2 of the second tooth 20 as it moves toward one side in the circumferential direction DR. The other end of the front end portion 40 in the circumferential direction DR is inclined so as to get closer to the second axial tooth center plane E2 of the second tooth 20 as it goes toward the other direction in the circumferential direction DR.

At least one second tooth 20 is preferably symmetrical with respect to a second axial tooth center plane E2 that bisects the at least one second tooth 20 in the axial direction DA in the axial direction DA relative to the rotation center axis CX. The second axial tooth center plane E2 bisects the second tooth 20 in the axial direction DA at the tooth root 20A of the second tooth 20. At least one second tooth 20 preferably has a second axial tooth end center plane F2 that is substantially consistent with the second axial tooth center plane E2 of the at least one second tooth 20 in the axial direction DA relative to the rotation center axis CX. The second axial tooth end center plane F2 bisects the second tooth 20 in the axial direction DA at the second radial outermost tooth end 20B of the second tooth 20. At least one second tooth 20 is symmetrical with respect to the second circumferential tooth root center line G2 in the circumferential direction DR relative to the rotation center axis CX. The second circumferential tooth root center line G2 is a straight line passing through the center point 20X and the rotation center axis CX when viewed from the axial direction DA; the center point 20X is the center point 20X of the tooth root 20A and the tooth root 18A adjacent to the other side of the tooth root 20A in the circumferential direction DR in the circumferential direction DR.

The first radial length L11 is defined between the first radial outermost tooth end 18B of at least one first tooth 18 in the radial direction BA relative to the rotation center axis CX and the rotation center axis CX. The second radial length L21 is defined between the second radial outermost tooth end 20B of at least one second tooth 20 in the radial direction BA relative to the rotation center axis CX and the rotation center axis CX. The first radial length L11 is preferably greater than the second radial length L21. The length L12 from the tooth root circle RC to the first radial outermost tooth end 18B is greater than the length L22 from the tooth root circle RC to the second radial outermost tooth end 20B. The crown circle TC1 of the first tooth 18 is located closer to the outer radial side B2 than the crown circle TC2 of the second tooth 20.

The first maximum chain engagement axial width W1 is greater than: the inner connecting rod axial space S1 defined by a pair of inner connecting rod pieces P1 of the chain P of the human-driven vehicle in the axial direction DA, and less than: the outer connecting rod axial space S2 defined by a pair of outer connecting rod pieces P2 of the chain P of the human-driven vehicle in the axial direction DA. The second maximum chain engagement axial width W2 is less than the inner connecting rod axial space S1. The first maximum chain engagement axial width W1 of at least one first tooth 18 is preferably more than 75% of the outer connecting rod axial space S2. The first maximum chain engagement axial width W1 of at least one first tooth 18 is preferably more than 80% of the outer connecting rod axial space S2. The second maximum chain engagement axial width W2 of at least one second tooth 20 is preferably more than 75% of the inner connecting rod axial space S1. The second maximum chain engagement axial width W2 of at least one second tooth 20 is preferably more than 80% of the inner connecting rod axial space S1.

(Second embodiment) The sprocket 50 of the second embodiment is described with reference to FIGS. 8 to 10. The sprocket 50 of the second embodiment is the same as the sprocket 10 of the first embodiment except for the sprocket teeth 52, so the same symbols as those of the first embodiment are added to the common structures with the first embodiment, and repeated descriptions are omitted.

The sprocket 50 is a human-powered vehicle sprocket 50 that rotates around a rotation center axis CX. The sprocket 50 may be a front sprocket or a rear sprocket. In this embodiment, the sprocket 50 is referred to as a front sprocket for explanation.

The sprocket 50 includes a sprocket body 12 and a plurality of sprocket teeth 52 disposed around an outer peripheral portion 14 of the sprocket body 12. The plurality of sprocket teeth 52 include at least one first tooth 54 having a first maximum chain engagement axial width W1 relative to the rotation center axis CX, and at least one second tooth 56 having a second maximum chain engagement axial width W2 relative to the rotation center axis CX. The first maximum chain engagement axial width W1 is greater than the second maximum chain engagement axial width W2 in the axial direction DA relative to the rotation center axis CX. At least one first tooth 54 includes a first driving surface K1, and the first driving surface K1 has: a first predetermined chain roller contact point J1 for defining the pitch circle diameter HX of the sprocket 50 for the human-powered vehicle. At least one second tooth 56 includes a second driving surface K2, and the second driving surface K2 has: a second predetermined chain roller contact point J2 for defining the pitch circle diameter HX of the sprocket 50 for the human-powered vehicle. A first tangent M11 is defined at the first predetermined chain roller contact point J1 relative to the first driving surface K1. A second tangent M21 is defined at the second predetermined chain roller contact point J2 relative to the second driving surface K2. The first reference line M12 is defined as passing through the rotation center axis CX and the first predetermined chain roller contact point J1. The second reference line M22 is defined as passing through the rotation center axis CX and the second predetermined chain roller contact point J2. The first vertex angle N1 is defined between the first tangent line M11 and the first reference line M12 at the radial inner side B1 from the first predetermined chain roller contact point J1. The second vertex angle N2 is defined between the second tangent line M21 and the second reference line M22 at the radial inner side B1 from the second predetermined chain roller contact point J2. The first vertex angle N1 is different from the second vertex angle N2. The first predetermined chain roller contact point J1 and the second predetermined chain roller contact point J2 are arranged on the same pitch circle RP.

The first vertex angle N1 is smaller than the second vertex angle N2. The difference between the first vertex angle N1 and the second vertex angle N2 is preferably 3 degrees or more. The difference between the first vertex angle N1 and the second vertex angle N2 is preferably 7 degrees or less. When the number of teeth of the sprocket gear 52 is 40 to 42, the first vertex angle N1 is included in the range of 5 degrees to 20 degrees, and the second vertex angle N2 is included in the range of 5 degrees to 20 degrees. When the number of teeth of the sprocket gear 52 is 40, for example, the first vertex angle N1 is 11.81 degrees, and the second vertex angle N2 is 15.91 degrees. When the number of teeth of the sprocket gear 52 is 42, for example, the first vertex angle N1 is 11.72 degrees, and the second vertex angle N2 is 15.82 degrees.

At least one first tooth 54 is a single integral member having a first maximum chain engagement axial width W1 and preferably includes at least one axial ridge 58 formed integrally with at least one first tooth 54. At least one axial ridge 58 has a radial outermost end 60 and a radial innermost end 62 relative to the rotation center axis CX. The radial innermost end 62 of the at least one axial ridge 58 is arranged closer to the radial outer side B2 than the tooth root 54A of the at least one first tooth 54, or is at the same position as the tooth root 54A of the at least one first tooth 54 in the radial direction BA. The radial innermost end 62 of at least one axial raised portion 58 may be arranged closer to the radial inner side B1 than the tooth root 54A of at least one first tooth 54. At least one axial raised portion 58 has an inclined portion 64 extending from the radial innermost end 62 toward the radial outer side B2. The inclined portion 64 of at least one axial raised portion 58 is inclined relative to the third axial tooth center plane that divides at least one first tooth 54 into two equal parts in the axial direction DA.

The at least one first tooth 54 preferably includes a plurality of first teeth 54. The at least one second tooth 56 preferably includes a plurality of second teeth 56. The plurality of first teeth 54 and the plurality of second teeth 56 are alternately arranged in the circumferential direction DR relative to the rotation center axis CX. The number of first teeth 54 is preferably equal to the number of second teeth 56. The tooth root 54A of the first tooth 54 and the tooth root 56A of the second tooth 56 are arranged on the same tooth root circle RC. The tooth root circle RC is substantially equal to the outermost end 14A of the outer peripheral portion 14 in the radial direction BA. Here, the term "tooth root 54A of the first tooth 54" represents the tooth root 54A adjacent to the first tooth 54 as the target in one direction of the circumferential direction DR. Similarly, the term "tooth root 56A of the second tooth 56" represents the tooth root 56A adjacent to the second tooth 56 as the target in one direction of the circumferential direction DR.

At least one axial raised portion 58 is preferably provided on both sides of at least one first tooth 54 in the axial direction DA. At least one axial raised portion 58 is preferably provided on both sides of all first teeth 54 in the axial direction DA. When the sprocket 50 is a rear sprocket, the axial raised portion 58 may be provided on only one side of the first tooth 54 in the axial direction DA in order to allow the speed change action of the rear derailleur to be performed smoothly.

The inclined portion 64 of at least one axial protrusion 58 extends from the radial innermost end portion 62 toward the radial outer side B2 in the radial direction BA relative to the rotation center axis CX. The inclined portion 64 of at least one axial protrusion 58 may extend from the radial innermost end portion 62 toward the radial outer side B2 beyond the tooth root 54A of at least one first tooth 54 in the radial direction BA relative to the rotation center axis CX. The inclined portion 28 is inclined so as to get closer to the third axial tooth center plane of the first tooth 54 as it moves toward the radial inner side B1.

The axially raised portion 58 further includes: a middle portion 66 and a front end portion 68. The middle portion 66 is continuous with the radially outer side B2 portion of the inclined portion 28. The front end portion 68 is continuous with the radially outer side B2 portion of the middle portion 66. The front end portion 68 is inclined so as to get closer to the third axial tooth center plane of the first tooth 54 as it moves toward the radially outer side B2. The middle portion 34 has a first maximum chain engagement axial width W1. One end of the middle portion 66 in the circumferential direction DR is inclined so as to get closer to the third axial tooth center plane of the first tooth 54 as it moves toward one of the circumferential directions DR. The other end portion of the intermediate portion 66 in the circumferential direction DR is inclined so as to come closer to the third-axial tooth center plane of the first tooth 54 as it goes toward the other side in the circumferential direction DR.

At least one first tooth 54 is preferably symmetrical with respect to the third-axis tooth center plane in the axial direction DA relative to the rotation center axis CX. At least one first tooth 54 preferably has a third-axis tooth end center plane substantially consistent with the third-axis tooth center plane of at least one first tooth 54 in the axial direction DA relative to the rotation center axis CX. The third-axis tooth end center plane bisects the first tooth 54 in the axial direction DA at the first radial outermost tooth end 18B of the first tooth 54. At least one first tooth 54 is symmetrical with respect to the third circumferential tooth root center line G3 in the circumferential direction DR relative to the rotation center axis CX. When at least one axial raised portion 58 is provided on each of the two surfaces in the axial direction DA of the first tooth 54, the axial raised portion 58 may be symmetrical with respect to the third circumferential tooth root center line G3. The third circumferential tooth root center line G3 is a straight line passing through the center point 54X and the rotation center axis CX when viewed from the axial direction DA; the center point 54X is the center point 54X in the circumferential direction DR of the tooth root 54A and the tooth root 56A adjacent to the tooth root 54A on the other side in the circumferential direction DR.

The second tooth 56 includes a base end portion 38 and a front end portion 40. The second tooth 56 has the same shape as the second tooth 20 of the first embodiment.

The first radial length L13 is defined between the first radial outermost tooth end 54B of at least one first tooth 54 in the radial direction BA relative to the rotation center axis CX and the rotation center axis CX. The second radial length L23 is defined between the second radial outermost tooth end 56B of at least one second tooth 56 in the radial direction BA relative to the rotation center axis CX and the rotation center axis CX. The first radial length L13 is preferably greater than the second radial length L23. The length L14 from the tooth root circle RC to the first radial outermost tooth end 54B is greater than the length L24 from the tooth root circle RC to the second radial outermost tooth end 56B. The crown circle TC1 of the first tooth 54 is located closer to the radial outer side B2 than the crown circle TC2 of the second tooth 56 .

The first maximum chain engagement axial width W1 is greater than: the inner connecting rod axial space S1 defined by a pair of inner connecting rod pieces P1 of the chain P of the human-driven vehicle in the axial direction DA, and less than: the outer connecting rod axial space S2 defined by a pair of outer connecting rod pieces P2 of the chain P of the human-driven vehicle in the axial direction DA, and the second maximum chain engagement axial width W2 is less than the inner connecting rod axial space S1. The first maximum chain engagement axial width W1 of at least one first tooth 54 is preferably more than 75% of the outer connecting rod axial space S2. The first maximum chain engagement axial width W1 of at least one first tooth 54 is preferably more than 80% of the outer connecting rod axial space S2. The second maximum chain engagement axial width W2 of at least one second tooth 56 is preferably more than 75% of the inner connecting rod axial space S1. The second maximum chain engagement axial width W2 of at least one second tooth 56 is preferably more than 80% of the inner connecting rod axial space S1.

(Third embodiment) The sprocket 70 of the third embodiment is described with reference to FIGS. 11 to 13. The sprocket 70 of the third embodiment is the same as the sprocket 10 of the first embodiment and the sprocket 50 of the second embodiment except for the sprocket teeth 72. Therefore, the same symbols as those of the first and second embodiments are added to the common structures of the first and second embodiments, and repeated descriptions are omitted.

The sprocket 70 is a human-powered vehicle sprocket 70 that rotates around a rotation center axis CX. The sprocket 70 may be a front sprocket or a rear sprocket. In this embodiment, the sprocket 70 is referred to as a front sprocket for explanation.

The sprocket 70 includes a sprocket body 12 and a plurality of sprocket teeth 72 disposed around an outer peripheral portion 14 of the sprocket body 12. The plurality of sprocket teeth 72 include at least one first tooth 18 having a first maximum chain engagement axial width W1 relative to the rotation center axis CX, at least one second tooth 20 having a second maximum chain engagement axial width W2 relative to the rotation center axis CX, and at least one third tooth 74 having a third maximum chain engagement axial width WX relative to the rotation center axis CX. The first maximum chain engagement axial width W1 and the third maximum chain engagement axial width WX are respectively greater than the second maximum chain engagement axial width W2 in the axial direction DA relative to the rotation center axis CX. At least one first tooth 18 includes: at least one axial ridge 22 having the first maximum chain engagement axial width W1. At least one axial ridge 22 has: a radial outermost end 24 and a radial innermost end 26 relative to the rotation center axis CX. The radial innermost end 26 is arranged at a radial position. At least one third tooth 74 includes: at least one additional axial protrusion 76 having a third maximum chain engagement axial width WX. At least one additional axial protrusion 76 has: an additional radial outermost end 78 and an additional radial innermost end 80 relative to the rotation center axis CX. The additional radial innermost end 80 is arranged at an additional radial position. The radial position of the radial innermost end 26 of at least one axial protrusion 22 is different from the additional radial position of the additional radial innermost end 80 of at least one additional axial protrusion 76.

At least one first tooth 18 preferably includes a plurality of first teeth 18. At least one second tooth 20 preferably includes a plurality of second teeth 20. At least one third tooth 74 preferably includes a plurality of third teeth 74. The outer periphery 14 of the sprocket body 12 includes: a high load area RA with a large pedal load, and a low load area RB with a small pedal load. At least one first tooth 18 is arranged in the high load area RA. At least one third tooth 74 is arranged in the low load area RB. The high load area RA and the low load area RB are determined in advance through experiments, etc. In one example, the low load region RB includes the top dead center and the bottom dead center relative to the crank arm A when the sprocket 70 is viewed from the axial direction DA, and extends in the circumferential direction DR relative to the rotation center axis CX near the top dead center of the crank arm A and near the bottom dead center of the crank arm A for a predetermined length; the high load region RA is located in the circumferential direction DR relative to the rotation center axis CX when the sprocket 70 is viewed from the axial direction DA, and is located between the low load region RB including the top dead center of the crank arm A and the low load region RB including the bottom dead center of the crank arm A. For example, the sprocket body 12 includes two high load regions RA and two low load regions RB. In the circumferential direction DR, the high-load area RA and the low-load area RB are alternately arranged. In the high-load area RA, the first teeth 18 and the second teeth 20 are preferably alternately arranged in the circumferential direction DR relative to the rotation center axis CX. In the low-load area RB, the third teeth 74 and the second teeth 20 are preferably alternately arranged in the circumferential direction DR relative to the rotation center axis CX. The number of the first teeth 18 and the number of the second teeth 20 may be equal to or different. The number of the first teeth 18 and the number of the third teeth 74 may be equal to or different. The number of the second teeth 20 and the number of the third teeth 74 may be equal to or different.

In this embodiment, the first tooth 18 has the same shape as the first tooth 18 of the first embodiment. The axial raised portion 22 has the same shape as the axial raised portion 22 of the first embodiment. In this embodiment, the second tooth 20 has the same shape as the second tooth 20 of the first embodiment.

The third tooth 74 may have the same shape as the first tooth 54 of the second embodiment. The additional axial protrusion 76 may have the same shape as the axial protrusion 58 of the second embodiment. The radial innermost end 26 of at least one axial protrusion 22 is preferably arranged closer to the radial inner side B1 than the tooth root 18A of at least one first tooth 18. The additional radial innermost end 80 of at least one additional axial protrusion 76 is arranged at a position closer to the radial outer side B2 than the tooth root 74A of at least one third tooth 74, or at the same position as the tooth root 74A of at least one third tooth 74 in the radial direction BA. The additional radial innermost end 80 of at least one additional axial ridge 76 may be arranged closer to the radial inner side B1 than the tooth root 74A of at least one third tooth 74. The at least one additional axial ridge 76 has an inclined portion 82 extending from the additional radial innermost end 80 toward the radial outer side B2. The inclined portion 82 of at least one additional axial ridge 76 is inclined relative to the third axial tooth center plane E3 that divides the at least one third tooth 74 into two equal parts in the axial direction DA.

At least one axial raised portion 76 is preferably provided on both sides of at least one third tooth 74 in the axial direction DA. At least one axial raised portion 76 is preferably provided on both sides of all third teeth 74 in the axial direction DA. When the sprocket 70 is a rear sprocket, the additional axial raised portion 76 may be provided on only one side of the third tooth 74 in the axial direction DA in order to allow the speed change action of the rear derailleur to be performed smoothly.

The inclined portion 82 of at least one additional axial protrusion 76 extends from the radial innermost end portion 80 toward the radial outer side B2 in the radial direction BA relative to the rotation center axis CX. The inclined portion 82 of at least one additional axial protrusion 76 may extend from the additional radial innermost end portion 80 toward the radial outer side B2 beyond the tooth root 74A of at least one third tooth 74 in the radial direction BA relative to the rotation center axis CX. The inclined portion 82 is inclined so as to get closer to the third axial tooth center surface E3 of the third tooth 74 as it moves toward the radial inner side B1.

The additional axial protrusion 76 further includes: a middle portion 84 and a front end portion 86. The middle portion 84 is continuous with the radially outer side B2 portion of the inclined portion 82. The front end portion 86 is continuous with the radially outer side B2 portion of the middle portion 84. The front end portion 86 is inclined so as to get closer to the third axial tooth center plane E3 of the third tooth 74 as it moves toward the radially outer side B2. The middle portion 84 has a third maximum chain engagement axial width WX. The end portion of one side of the circumferential direction DR of the middle portion 84 is inclined so as to get closer to the third axial tooth center plane E3 of the third tooth 74 as it moves toward one side of the circumferential direction DR. The other end portion of the intermediate portion 84 in the circumferential direction DR is inclined so as to get closer to the third axial tooth center plane E3 of the third tooth 74 as it goes toward the other side in the circumferential direction DR.

At least one third tooth 74 is preferably symmetrical with respect to the third axial tooth center plane E3 in the axial direction DA relative to the rotation center axis CX. At least one third tooth 74 preferably has a third axial tooth end center plane F3 substantially consistent with the third axial tooth center plane E3 of at least one third tooth 74 in the axial direction DA relative to the rotation center axis CX. The third axial tooth end center plane F3 bisects the third tooth 74 in the axial direction DA at the third radial outermost tooth end 74B of the third tooth 74. At least one third tooth 74 is symmetrical with respect to the third circumferential tooth root center line G3 in the circumferential direction DR relative to the rotation center axis CX. When at least one additional axial protrusion 76 is provided on each of the two sides in the axial direction DA of the third tooth 74, the additional axial protrusion 76 may be symmetrical with respect to the third circumferential tooth root center line G3. The third circumferential tooth root center line G3 is a straight line passing through the center point 74X and the rotation center axis CX when viewed from the axial direction DA; the center point 74X is the center point 74X in the circumferential direction DR of the tooth root 74A and the tooth root 20A adjacent to the tooth root 74A on the other side in the circumferential direction DR.

The first maximum chain engagement axial width W1 and the third maximum chain engagement axial width WX are respectively greater than: the inner connecting rod axial space S1 defined by a pair of inner connecting rod pieces P1 of the chain P of the human-powered vehicle in the axial direction DA, and are respectively less than: the outer connecting rod axial space S2 defined by a pair of outer connecting rod pieces P2 of the chain P of the human-powered vehicle in the axial direction DA, and the second maximum chain engagement axial width W2 is less than the inner connecting rod axial space S1. Preferably, the first maximum chain engagement axial width W1 and the third maximum chain engagement axial width WX are equal. The third maximum chain engagement axial width WX of at least one third tooth 74 is preferably 75% or more of the outer connecting rod axial space S2. The third maximum chain engagement axial width WX of at least one third tooth 74 is preferably 80% or more of the outer connecting rod axial space S2. The second maximum chain engagement axial width W2 of at least one second tooth 20 is preferably 75% or more of the inner connecting rod axial space S1. The second maximum chain engagement axial width W2 of at least one second tooth 20 is preferably 80% or more of the inner connecting rod axial space S1.

(Variation) The description of the above embodiment is an example of the form that the sprocket for a human-powered vehicle of the present invention can take, and is not intended to limit its form. The sprocket for a human-powered vehicle of the present invention can take the form of a variation of the above embodiment shown below and a combination of at least two variations that do not contradict each other. In the following variations, the same symbols as the embodiment are added to the parts that are common to the embodiment, and their description is omitted.

As shown in FIG. 14 and FIG. 15, the first vertex angle N1 may be greater than the second vertex angle N2. The difference between the first vertex angle N1 and the second vertex angle N2 is preferably 3 degrees or more. The difference between the first vertex angle N1 and the second vertex angle N2 is preferably 7 degrees or less. When the number of teeth of the sprocket tooth 52 is 40 to 42, the first vertex angle N1 is preferably within the range of 5 degrees to 20 degrees, and the second vertex angle N2 is preferably within the range of 5 degrees to 20 degrees. When the number of teeth of the sprocket tooth 52 is 40, for example, the first vertex angle N1 is 15.91 degrees, and the second vertex angle N2 is 11.81 degrees. When the number of teeth of the sprocket gear 52 is 42, for example, the first vertex angle N1 is 15.82 degrees, and the second vertex angle N2 is 11.72 degrees.

In the first embodiment and the third embodiment, as shown in FIG. 16 , at least one first tooth 18 may be asymmetric with respect to the first circumferential tooth root center line V1 in the circumferential direction DR relative to the rotation center axis CX.

In the first and third embodiments, as shown in FIG. 17 , at least one first tooth 18 may be asymmetrical with respect to the first axial tooth center plane E1 in the axial direction DA relative to the rotation center axis CX. In this case, the axial raised portion 22 may be provided only on one side of the first tooth 18.

In the first embodiment and the third embodiment, as shown in FIG. 16 , at least one second tooth 20 may be asymmetric with respect to the second circumferential tooth root center line V2 in the circumferential direction DR relative to the rotation center axis CX.

In the first embodiment and the third embodiment, as shown in FIG. 17 , at least one second tooth 20 may be asymmetric in the axial direction DA relative to the rotation center axis CX with respect to the second axial tooth center plane E2 that bisects at least one second tooth 20 in the axial direction DA.

In the first embodiment and the third embodiment, as shown in FIG. 17 , at least one first tooth 18 may have a first axial tooth center line Q1 offset from a first axial tooth center plane E1 of at least one first tooth 18 in the axial direction DA relative to the rotation center axis CX.

In the first embodiment and the third embodiment, as shown in FIG. 17 , at least one second tooth 20 may include a second axial tooth center line Q2 offset from a second axial tooth center plane E2 that bisects the at least one second tooth 20 in the axial direction DA.

In the second embodiment, at least one first tooth 54 may be asymmetrical with respect to the tooth root center line in the third circumferential direction in the circumferential direction DR relative to the rotation center axis CX.

In the second embodiment, at least one first tooth 54 may be asymmetric with respect to the tooth center plane in the third axial direction in the axial direction DA relative to the rotation center axis CX.

In the second embodiment, at least one second tooth 56 may be asymmetric with respect to the second circumferential tooth root center line in the circumferential direction DR relative to the rotation center axis CX.

In the second embodiment, at least one second tooth 56 may be asymmetric in the axial direction DA relative to the rotation center axis CX and with respect to a second axial tooth center plane that bisects at least one second tooth 20 in the axial direction DA.

In the second embodiment, at least one first tooth 54 may have a third-axis tooth center line offset from a third-axis tooth center plane of at least one first tooth 18 in the axial direction DA relative to the rotation center axis CX.

In the second embodiment, at least one second tooth 20 may include a second axial tooth center line offset from a second axial tooth center plane E2 that bisects the at least one second tooth 20 in the axial direction DA.

In the third embodiment, at least one third tooth 74 may be asymmetric with respect to the third circumferential tooth root center line G3 in the circumferential direction DR relative to the rotation center axis CX.

In the third embodiment, at least one third tooth 74 may be asymmetrical with respect to the third axial tooth center plane E3 in the axial direction DA relative to the rotation center axis CX. In this case, the axial raised portion 22 may be provided only on one side of the third tooth 74.

In the third embodiment, at least one third tooth 74 may have a third axial tooth center line offset from a third axial tooth center plane E3 of at least one third tooth 74 in the axial direction DA relative to the rotation center axis CX.

As shown in Fig. 18, in the second embodiment, a step portion may be formed on the first driving surface K1 of the first tooth 54. In this case, the first driving surface K1, the first tangent line M11, and the first reference line M12 are defined by the chain roller contact point J1 in the first tooth 54 that contacts the chain roller.

As shown in Fig. 18, in the second embodiment, a step portion may be formed on the second driving surface K2 of the second tooth 56. In this case, the second driving surface K2, the second tangent line M21, and the second reference line M22 are defined by the chain roller contact point J2 in the second tooth 56 that contacts the chain roller.

In the second embodiment and the third embodiment, the axial protrusion 22 of the first tooth 18 may be provided as a separate entity from the first tooth 18 and mounted on the first tooth 18.

The expression "at least one" used in this specification means "more than one" of the required options. As an example, if the number of options is two, the expression "at least one" used in this specification means "only one option" or "both options". As another example, if the number of options is three or more, the expression "at least one" used in this specification means "only one option" or "a combination of any two or more options".

10, 50, 70: sprocket 12: sprocket body 14: periphery 16, 52, 72: sprocket teeth 18, 54: 1st tooth 18A, 54A: tooth root 18B, 54B: 1st radial outermost tooth end 20, 56: 2nd tooth 20B: 2nd radial outermost tooth end 22, 58: axial direction Raised part 24, 60: radial outermost end 26, 62: radial innermost end 28, 64: inclined part 74: third tooth 76: additional axial raised part 78: additional radial outermost end 80: additional radial innermost end 82: inclined part P: chain P1: inner connecting rod P2: outer connecting rod

FIG. 1 is a front view of the sprocket for human-powered vehicle of the first embodiment. FIG. 2 is a front view of the state where the covering portion of the sprocket for human-powered vehicle of FIG. 1 is omitted. FIG. 3 is a front view showing a part of FIG. 1 in an enlarged manner. FIG. 4 is a stereoscopic view of FIG. 3. FIG. 5 is a top view of the sprocket for human-powered vehicle of FIG. 1. FIG. 6 is a cross-sectional view along line 6-6 of FIG. 1. FIG. 7 is a cross-sectional view along line 7-7 of FIG. 1. FIG. 8 is a front view of the state where the covering portion of the sprocket for human-powered vehicle of the second embodiment is omitted. FIG. 9 is a front view showing the first tooth of FIG. 8 in an enlarged manner. FIG. 10 is a front view showing the second tooth of FIG. 8 in an enlarged manner. FIG. 11 is a front view of the sprocket for human-powered vehicle of the third embodiment. FIG. 12 is a top view of the sprocket for human-powered vehicle of FIG. 11. FIG. 13 is a front view showing a part of FIG. 11 in an enlarged manner. FIG. 14 is a front view showing a first tooth of the first variant in an enlarged manner. FIG. 15 is a front view showing a second tooth of the first variant in an enlarged manner. FIG. 16 is a front view showing a part of the sprocket for human-powered vehicle of the second variant in an enlarged manner. FIG. 17 is a top view of the sprocket for human-powered vehicle of FIG. 16. FIG. 18 is a front view showing a part of the sprocket for human-powered vehicle of the third variant in an enlarged manner.

10: Sprocket

12: Sprocket body

14: Periphery

16: Sprocket gear

18: 1st tooth

18A: Tooth root

18B: The outermost tooth end in the first radial direction

18X: Center point

20: 2nd tooth

20A: Tooth root

20B: The outermost tooth end of the second diameter

20X: Center point

22: Axial ridges

24: radial outermost end

26: radial innermost end

28: Inclined part

30: Covering part

30A: Outermost end

34: Middle part

36: Front end

38: Base end

40: Front end

B1: Diameter inward

B2: radially outward

BA: radial

DA: Axial direction

DR: Weekly direction

G1: Centerline of tooth root in the first rotation direction

G2: Center line of tooth root in the second week direction

L12: Length

L22: Length

TC1: Crown round

TC2: Crown round

RC: tooth root circle

Claims (28)

A sprocket is a sprocket for a human-powered vehicle that rotates around a rotation center axis, and comprises: a sprocket body, and a plurality of sprocket teeth arranged around the outer periphery of the sprocket body; the plurality of sprocket teeth include: at least one first tooth having a first maximum chain engagement axial width relative to the rotation center axis, and at least one second tooth having a first maximum chain engagement axial width relative to the rotation center axis. The rotation center axis has at least one second tooth with a second maximum chain engagement axial width; the first maximum chain engagement axial width is greater than the second maximum chain engagement axial width in the axial direction relative to the rotation center axis, and the at least one first tooth, as a tooth with the first maximum chain engagement axial width A single integral component includes at least one axial protrusion formed integrally with the at least one first tooth; the at least one axial protrusion has: a radial outermost end and a radial innermost end relative to the rotation center axis; the radial innermost end of the at least one axial protrusion is arranged closer to the radial inner side than the tooth root of the at least one first tooth; the at least one axial protrusion has an inclined portion extending from the radial innermost end toward the radial outer side; the inclined portion of the at least one axial protrusion is inclined relative to the first axial tooth center plane that bisects the at least one first tooth in the axial direction. For example, in the sprocket of claim 1, the inclined portion of the at least one axially raised portion extends radially outward from the radial innermost end portion beyond the tooth root of the at least one first tooth in the radial direction relative to the rotation center axis. For the sprocket of item 1 or 2 of the patent application, the first maximum chain engagement axial width is greater than: the inner connecting rod axial space defined by a pair of inner connecting rod pieces facing each other in the chain of a human-driven vehicle in the above-mentioned axial direction, and less than: the outer connecting rod axial space defined by a pair of outer connecting rod pieces facing each other in the chain of a human-driven vehicle in the above-mentioned axial direction; the second maximum chain engagement axial width is less than the inner connecting rod axial space. For example, in the sprocket of item 3 of the patent application, the first maximum chain engagement axis direction width of the at least one first tooth is more than 75% of the space in the axis direction of the outer connecting rod. For a sprocket as claimed in item 1 or 2 of the patent application, the first radial length is defined as the distance between the first radial outermost tooth end of the at least one first tooth and the rotation center axis in the radial direction relative to the rotation center axis; The second radial length is defined as the distance between the second radial outermost tooth end of the at least one second tooth and the rotation center axis in the radial direction relative to the rotation center axis; the first radial length is greater than the second radial length. For example, in the sprocket of item 1 or 2 of the patent application, the at least one first tooth has, in the axial direction relative to the rotation center axis, a first axial tooth center line offset from the first axial tooth center plane of the at least one first tooth. For example, in the sprocket of item 1 or 2 of the patent application, the at least one second tooth has: a second axial tooth center line offset from a second axial tooth center plane that bisects the at least one second tooth in the axial direction. For example, in the sprocket of item 1 or 2 of the patent application, the at least one first tooth is asymmetrical relative to the center line of the tooth root in the first circumferential direction in the circumferential direction relative to the rotation center axis. For example, in the sprocket of item 1 or 2 of the patent application, the at least one first tooth is symmetrical with respect to the center line of the first tooth root in the circumferential direction relative to the rotation center axis. For example, in the sprocket of item 1 or 2 of the patent application, the at least one first tooth is asymmetrical relative to the center plane of the tooth in the first axial direction in the axial direction relative to the rotation center axis. For example, in the sprocket of item 1 or 2 of the patent application, the at least one first tooth is symmetrical with respect to the center plane of the tooth in the first axial direction in the axial direction relative to the rotation center axis. For example, in the sprocket of item 1 or 2 of the patent application, the at least one second tooth is asymmetrical relative to the center line of the tooth root in the second circumferential direction in the circumferential direction relative to the rotation center axis. For a sprocket as claimed in item 1 or 2 of the patent application, the at least one second tooth is symmetrical with respect to the center line of the tooth root in the second circumferential direction in the circumferential direction relative to the rotation center axis. For example, in the sprocket of item 1 or 2 of the patent application, the at least one second tooth is asymmetrical in the axial direction relative to the rotation center axis and relative to the second axial direction tooth center plane that bisects the at least one second tooth in the axial direction. For example, in the sprocket of item 1 or 2 of the patent application, the at least one second tooth is symmetrical in the axial direction relative to the rotation center axis and relative to the second axial direction tooth center plane that bisects the at least one second tooth in the axial direction. For example, the sprocket of item 1 or 2 of the patent application scope, wherein the at least one first tooth includes a plurality of first teeth, the at least one second tooth includes a plurality of second teeth, and the plurality of first teeth and the plurality of second teeth are alternately arranged in the circumferential direction relative to the rotation center axis. A sprocket is a sprocket for a human-powered vehicle that rotates around a rotation center axis, and comprises: a sprocket body, and a plurality of sprocket teeth arranged around the outer periphery of the sprocket body; the plurality of sprocket teeth include: at least one first tooth having a first maximum chain engagement axis direction width relative to the rotation center axis, and at least one second tooth having a second maximum chain engagement axis direction width relative to the rotation center axis; The first maximum chain engagement axial width is greater than the second maximum chain engagement axial width in the axial direction relative to the rotation center axis. The at least one first tooth includes a first driving surface, and the first driving surface is provided with: a first predetermined chain roller contact point for defining the pitch circle diameter of the sprocket for the human-powered vehicle; the at least one second tooth includes a second driving surface, and the second driving surface is provided with : used to define the second predetermined chain roller contact point of the pitch circle diameter of the sprocket for the human-powered vehicle; The first tangent line is defined at the first predetermined chain roller contact point relative to the first driving surface, and the second tangent line is defined at the second predetermined chain roller contact point relative to the second driving surface; the first reference line is defined as passing through the rotation center axis and the first predetermined chain roller contact point, and the second reference line , defined as passing through the above-mentioned rotation center axis and the above-mentioned second predetermined chain roller contact point; the first vertex angle is defined between the above-mentioned first tangent line and the above-mentioned first baseline in the radial direction inward from the above-mentioned first predetermined chain roller contact point, and the second vertex angle is defined between the above-mentioned second tangent line and the above-mentioned second baseline in the radial direction inward from the above-mentioned second predetermined chain roller contact point; the above-mentioned first vertex angle is different from the above-mentioned second vertex angle. For example, in the sprocket of item 17 of the patent application, the first vertex angle is greater than the second vertex angle. For example, in the sprocket of item 17 of the patent application, the first vertex angle is smaller than the second vertex angle. For example, in the sprocket of item 17 of the patent application, the difference between the first vertex angle and the second vertex angle is greater than 3 degrees. For example, in the sprocket of item 20 of the patent application, the difference between the first vertex angle and the second vertex angle is less than 7 degrees. For a sprocket of any one of items 17 to 21 of the patent application scope, the first maximum chain engagement axial width is greater than: the inner connecting rod axial space defined by a pair of inner connecting rod pieces facing each other in the above axial direction of the chain of a human-driven vehicle, and less than: the outer connecting rod axial space defined by a pair of outer connecting rod pieces facing each other in the above axial direction of the chain of a human-driven vehicle; the second maximum chain engagement axial width is less than the inner connecting rod axial space. A sprocket is a sprocket for a human-powered vehicle that rotates around a rotation center axis, and comprises: a sprocket body, and a plurality of sprocket teeth arranged around the outer periphery of the sprocket body; the plurality of sprocket teeth include: at least one first tooth having a first maximum chain engagement axis width relative to the rotation center axis, at least one second tooth having a second maximum chain engagement axis width relative to the rotation center axis, a second tooth, and at least one third tooth having a third maximum chain engagement axial width relative to the rotation center axis; the first maximum chain engagement axial width and the third maximum chain engagement axial width are respectively greater than the second maximum chain engagement axial width in the axial direction relative to the rotation center axis, and the at least one first tooth comprises: having the first maximum chain engagement axial width The at least one axially ridged portion has a maximum chain engagement axial width; the at least one axially ridged portion has: a radially outermost end portion and a radially innermost end portion relative to the rotation center axis; the radially innermost end portion is arranged at a radial position, the at least one third tooth has an additional axially ridged portion, the additional axially ridged portion has a third maximum chain engagement axial width, the at least An additional axial protrusion has: an additional radial outermost end and an additional radial innermost end relative to the rotation center axis; the additional radial innermost end is arranged at an additional radial position, and the radial position of the radial innermost end of the at least one axial protrusion is different from the additional radial position of the additional radial innermost end of the at least one additional axial protrusion. For example, in the sprocket of claim 23, the radial innermost end of the at least one axial protrusion is arranged closer to the radial inner side than the tooth root of the at least one first tooth. For example, in the sprocket of claim 24, the radial innermost end of the at least one additional axial protrusion is arranged at a position closer to the radial outer side than the tooth root of the at least one third tooth, or is arranged at the same position as the tooth root of the at least one third tooth in the radial direction. For example, in the sprocket of item 23 of the patent application, the first maximum chain engagement axis width is equal to the third maximum chain engagement axis width. For example, the sprocket of claim 25, wherein the outer peripheral portion of the sprocket body includes: a high-load region with a larger pedal load and a low-load region with a smaller pedal load; the at least one first tooth is disposed in the high-load region, and the at least one third tooth is disposed in the low-load region. For a sprocket of any one of items 23 to 27 of the patent application, the first maximum chain engagement axial width and the third maximum chain engagement axial width are respectively greater than: the inner connecting rod axial direction space defined by a pair of inner connecting rod pieces facing each other in the above axial direction of the chain of a human-driven vehicle, and are respectively less than: the outer connecting rod axial direction space defined by a pair of outer connecting rod pieces facing each other in the above axial direction of the chain of a human-driven vehicle; the second maximum chain engagement axial width is less than the inner connecting rod axial direction space.

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