Bicycle sprocket and bicycle sprocket arrangement

Abstract

Bicycle sprocket (12; 212) comprising: a pinion body (18) having a radial outer circumference (22) provided around a rotational center axis (A1) of the bicycle sprocket (12; 212); and a plurality of chain drive teeth (20) provided on the radial outer circumference (22) to engage with a bicycle chain (BC), the plurality of chain drive teeth (20) comprising: a first tooth (24), having a first maximum chain engagement width (W1), defined in an axial direction (D2) parallel to the axis of rotation (A1), wherein the first tooth (24) has a first radially outermost end (24C) radially furthest from the radial outer circumference (22) of the pinion body (18), wherein the first tooth (24) has a first radial length (L1) radially defined from a reference line (RL1) to the first radially outermost end (24C); and a second tooth (26; 226) with a second maximum chain engagement width (W2), defined in the axial direction (D2), wherein the first maximum chain engagement width (W1) is larger than an inner link space (BC11), defined between an opposing pair of inner link plates (BC1; BC1X) of the bicycle chain (BC) and smaller than an outer link space (BC21), defined between an opposing pair of outer link plates (BC2; BC2X) of the bicycle chain (BC), wherein the second maximum chain engagement width (W2) is smaller than the inner link space (BC11), and wherein the second tooth (26; 226) has a second radially outermost end (26C), radially furthest from the radial outer circumference (22) of the sprocket body (18), wherein the second tooth (26; 226) has a second radial length (L2), radially defined from the reference line (RL1) to the second radially outermost end (26C), wherein the second radial length (L2) is in a range of 1.5 mm to 2.9 mm, and wherein the second tooth (26; 226) has a circumferential mean plane (CP2) extending radially from the rotation mean axis (A1) through a midpoint (P1) of a reference line (RL1), wherein the reference line (RL1) is defined to connect centers (BC31) of pins BC3) of the bicycle chain (BC) which engages with the plurality of chain drive teeth (20), and wherein a trailing circumferential surface (32) has in a drive rotation direction (D11) in which the bicycle sprocket (12; 212) rotates around the rotation center axis (A1) during pedaling, wherein the trailing circumferential surface (32) is arranged on a trailing side of the circumferential center plane (CP2) in the drive rotation direction (D11), and a shortest distance (L3) defined between the lagging circumferential surface (32) and a first intersection point (P21) of the circumferential mean plane (CP2) and a further reference line (RL2), wherein the shortest distance (L3) is equal to or greater than 2.0 mm and wherein the further reference line (RL2) is defined at a reference position (RP11; RP12; RP13) spaced radially outward from the reference line (RL1) by 1.5 mm.

Description

BACKGROUND OF THE INVENTION CROSS-REFERENCE TO OTHER REPORTS

[0001] This application claims priority from US patent application US 15 / 192,028, which was filed on June 24, 2016. Reference is hereby made to the entire disclosure of US patent application US 15 / 192,028. AREA OF INVENTION

[0002] The present invention relates to a bicycle sprocket and to a bicycle sprocket assembly. BACKGROUND DISCUSSION

[0003] Cycling is becoming an increasingly popular form of recreation, as well as a means of transportation. Furthermore, cycling has become a popular competitive sport for both amateurs and professionals. Whether the bicycle is used for recreation, transportation, or competition, the bicycle industry is constantly improving its various components. One bicycle component that has been extensively redesigned is the sprocket.

[0004] DE 10 2015 006 582 A1 discloses a bicycle chainring with chainring teeth, wherein the chainring teeth include at least one first tooth and at least one second tooth. The at least one first tooth has a first radial tooth height. The at least one first tooth has a first axial chain engagement width, which is less than a first distance defined between opposing outer connecting plates of a bicycle chain and which is greater than a second distance defined between opposing inner connecting plates of the bicycle chain. The at least one second tooth is adjacent to the first tooth and is arranged on a downstream side in a rotational drive direction of the bicycle chainring. The at least one second tooth is designed to engage with inner connecting plates of the bicycle chain. The at least one second tooth has a second radial tooth height.The first radial tooth height is greater than the second radial tooth height.

[0005] US 2007 / 0 049 437 A1 discloses bicycle chainrings for bicycles that feature specially designed ramps, tapers, and profiled teeth for improved shifting performance.

[0006] Bicycle chainrings for bicycles that feature specially designed ramps, tapers, and profiled teeth for improved shifting performance.

[0007] EP 0 642 972 B1 discloses a derailleur system with at least two sprockets on a sprocket unit, designed to facilitate switching the chain between a smaller and a larger sprocket. For this purpose, at least the larger sprocket has a double tooth gap, which forms a channel for the chain to pass between the two sprockets. A plate support ramp on the larger sprocket creates a radially convex or kinked profile for the chain transition path, which forms in the area of ​​the double tooth gap when the chain passes from the smaller sprocket to the larger sprocket. OVERVIEW OF THE INVENTION

[0008] In accordance with a first aspect of the present invention, a bicycle sprocket comprises a sprocket body and a plurality of chain drive teeth. The sprocket body has a radial outer circumference, which is provided with respect to a rotational center axis of the bicycle sprocket. The plurality of chain drive teeth are provided on the radial outer circumference to engage with a bicycle chain. The plurality of chain drive teeth comprises a first tooth and a second tooth. The first tooth has a first maximum chain engagement width, defined in an axial direction parallel to the rotational center axis. The first tooth has a first radially outermost end, which is radially furthest from the radial outer circumference of the sprocket body. The first tooth has a first radial length, defined radially from a reference line to the first radially outermost end.The second tooth has a second maximum chain engagement width, defined in the axial direction. The first maximum chain engagement width is larger than the inner link space defined between opposing pairs of inner link plates of the bicycle chain and smaller than the outer link space defined between opposing pairs of outer link plates of the bicycle chain. The second maximum chain engagement width is smaller than the inner link space. The second tooth has a second radially outermost end, which is radially furthest from the radial outer circumference of the sprocket body. The second tooth has a second radial length, which is defined radially from the reference line to the second radially outermost end. The second radial length is in the range of 1.5 mm to 2.9 mm. The second tooth has a circumferential center plane, a trailing circumferential surface, and a shortest distance.The circumferential median surface extends radially from the axis of rotation through the midpoint of a reference line. The reference line is defined to connect the centers of the pins of the bicycle chain, which engages with the multitude of chain drive teeth. The trailing circumferential surface is located in a drive rotation direction in which the bicycle sprocket rotates around the axis of rotation during pedaling. The trailing circumferential surface is located on a trailing side of the circumferential median plane in the drive rotation direction. The shortest distance is defined between the trailing circumferential surface and a first intersection of the circumferential median plane and another reference line. The shortest distance is equal to or greater than 2 mm. The second reference line is defined at least at one reference position, radially outward from the reference line by 1.5 mm.

[0009] With the bicycle sprocket, as described in the first aspect, it is possible to provide earlier timing at which the second tooth engages with the opposite pair of inner link plates of the bicycle chain. Accordingly, it is possible to bring the second tooth into smooth engagement with the opposite pair of inner link plates, even if the bicycle chain is at a sharp angle relative to the sprocket, when viewed from above. This can improve the chain retention performance of the bicycle sprocket.

[0010] Preferably, the first radial length is larger than the second radial length.

[0011] Consequently, it is possible to increase the area of ​​the chain engagement surface of the first tooth. This can reduce the tilt or angle of inclination of the opposing pair of outer link plates relative to the bicycle sprocket, even if the bicycle chain is angled relative to the sprocket when viewed from above. This can further improve the chain retention performance of the bicycle sprocket.

[0012] Preferably the second radial length is in a range of 2.0 mm to 2.5 mm or in a range of 2.5 mm to 2.9 mm.

[0013] Consequently, it is possible to adjust or select the second radial length to a suitable length in order to provide the earlier timing at which the second tooth engages the opposite pair of inner link plates of the bicycle chain. This can further improve the chain retention performance of the bicycle sprocket.

[0014] Preferably, the second tooth has a leading circumferential surface and a further shortest distance. The leading circumferential surface is oriented in a counter-rotational direction, opposite to the drive rotational direction. The leading circumferential surface is located on a leading side of the circumferential center plane in the drive rotational direction. The further shortest distance is defined between the circumferential center plane and the leading circumferential surface on the further reference line. The further shortest distance is preferably less than 2 mm.

[0015] Consequently, it is possible to save weight on the bicycle sprocket by providing the earlier timing at which the second tooth of the opposite pair of inner link plates of the bicycle chain engages.

[0016] In accordance with one embodiment of the present invention, the bicycle sprocket is configured such that the second tooth has a lagging connection surface, a leading circumferential surface, and a leading connection surface. The lagging connection surface extends between the lagging circumferential surface and the second radially outermost end. The leading circumferential surface points in a counter-rotational direction, opposite to the drive rotational direction. The leading circumferential surface is located on a leading side of the circumferential center plane in the drive rotational direction. The leading connection surface extends between the leading circumferential surface and the second radially outermost end. The lagging connection surface is further radially outward from the reference line than the leading connection surface.

[0017] In the bicycle sprocket according to the above embodiment, it is possible to save weight of the bicycle sprocket while providing the earlier timing at which the second tooth engages the opposite pair of inner link plates of the bicycle chain.

[0018] Preferably, the lagging connection surface has a center point defined between the lagging circumferential surface and the second radially outermost end, viewed from the axial direction. The leading connection surface can have a center point defined between the leading circumferential surface and the second radially outermost end, viewed from the axial direction. The center point of the lagging connection surface can be located radially farther from the reference line than the center point of the leading connection surface.

[0019] Consequently, it is possible to save weight on the bicycle sprocket by providing the earlier timing at which the second tooth engages the opposite pair of inner link plates of the bicycle chain.

[0020] In accordance with a further embodiment of the present invention, the bicycle sprocket is configured such that the second tooth has a trailing connecting surface extending between the trailing circumferential surface and the second radially outermost end, wherein the trailing connecting surface has a center point defined between the trailing circumferential surface and the second radially outermost end when viewed from the axial direction. An inclined reference line is defined between the center point of the trailing connecting surface and a second intersection of the circumferential center plane and the reference line when viewed from the axial direction. An inclination angle, defined between the circumferential center plane and the inclined reference line, is in a range of 32 degrees to 52 degrees when viewed from the axial direction.

[0021] Consequently, it is possible to adjust the position of the trailing contact surface to a suitable position to provide earlier timing at which the second tooth engages the opposite pair of inner link plates of the bicycle chain. This can further improve the chain retention performance of the bicycle sprocket. The helix angle has an optimal angle for the second radial length, ranging from 2.0 mm to 2.5 mm.

[0022] In accordance with a further embodiment, the bicycle sprocket is configured such that the second tooth has a trailing connecting surface extending between the trailing circumferential surface and the second radially outermost end, the trailing connecting surface having a center point defined between the trailing circumferential surface and the second radially outermost end when viewed from the axial direction. An inclined reference line is defined between the center point of the trailing connecting surface and a second intersection of the circumferential center plane and the reference line when viewed from the axial direction. A helix angle, defined between the circumferential center plane and the inclined reference line, is in a range of 29 degrees to 36.4 degrees when viewed from the axial direction.

[0023] In the bicycle sprocket according to the above embodiment, it is possible to adjust the position of the trailing contact surface to a suitable position in order to provide the earlier timing at which the second tooth engages the opposite pair of inner link plates of the bicycle chain. This can further improve the chain retention performance of the bicycle sprocket. The helix angle is at an optimal angle when the second radial length is in the range of 2.5 mm to 2.9 mm.

[0024] Preferably, the difference between the first radial length and the second radial length is equal to or less than 1.5 mm, preferably equal to or less than 1.0 mm.

[0025] Consequently, it is still possible to adjust the first and second radial lengths to suitable values ​​to provide the earlier timing at which the second tooth engages the opposite pair of inner link plates of the bicycle chain. This can further improve the chain retention performance of the bicycle chain.

[0026] Preferably, the first radial length is equal to or greater than 3.0 mm.

[0027] Consequently, it is possible to increase the area of ​​the chain's engagement surface on the first tooth. This can reduce the helix angle of the opposing pair of outer link plates relative to the sprocket, even if the chain is angled relative to the sprocket when viewed from above. This can further improve the chain retention performance.

[0028] Preferably, the first radial length is equal to or less than 4.0 mm.

[0029] Consequently, it is possible to increase the area of ​​the chain engagement surface of the first tooth. This can reduce the helix angle of the opposing pair of outer link plates relative to the sprocket, even if the chain is angled relative to the sprocket when viewed from above. This can further improve the chain retention performance of the sprocket. Furthermore, it is possible to prevent the tip of the first tooth from protruding radially outward from the opposing pair of outer link plates. This can reduce damage to the tip of the first tooth caused by collisions with obstacles.

[0030] Preferably, the bicycle sprocket also has a crank mounting part to couple the sprocket body to a bicycle crank.

[0031] Consequently, it is possible to apply the structure of the bicycle sprocket to a front sprocket or chainring.

[0032] Another aspect of the bicycle sprocket arrangement is the bicycle sprocket itself, as described above. The bicycle sprocket can be a single sprocket, without any other sprocket in the bicycle sprocket arrangement.

[0033] Consequently, it is possible to further improve the chain retention performance of the bicycle sprocket arrangement. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] A more comprehensive appreciation of the invention and many of its advantages can easily be obtained by referring to the following detailed description and taking into account the accompanying drawings. Fig. Figure 1 is a side view of a bicycle sprocket assembly comprising a bicycle sprocket in accordance with a first embodiment. Fig. 2 is another side view of the bicycle sprocket arrangement shown in Fig. 1. Fig. Figure 3 is a semi-perspective view of the bicycle sprocket in Fig. 1. Bicycle sprocket arrangement shown. Fig. 4 is another semi-perspective view of the bicycle sprocket shown in Fig. 1. Bicycle sprocket arrangement shown. Fig. Figure 5 is another semi-perspective view of the bicycle sprocket shown in Fig. 1. Bicycle sprocket arrangement shown. Fig. Figure 6 is another semi-perspective view of the bicycle sprocket shown in Fig. 1. Bicycle sprocket arrangement shown. Fig. 7 is a partial top view of the bicycle sprocket of the in Fig. 1. Bicycle sprocket arrangement shown. Fig. 8 is a sectional view of the bicycle sprocket, seen along a line VIII - VIII of the Fig. 10. Fig. 9 is a sectional view of the bicycle sprocket, seen along a line IX-IX of Fig. 10. Fig. Figure 10 shows a partial side view of the bicycle sprocket of the bicycle sprocket assembly shown in Fig. 1. Fig. 11 is another partial side view of the bicycle sprocket of the bicycle sprocket assembly shown in Fig. 1. Fig. Figure 12 shows an enlarged side view of the first tooth of the bicycle sprocket. Fig. 1. Fig. 13 is another enlarged side view of the first tooth of the in Fig. 1. Bicycle sprocket shown. Fig. 14 is an enlarged side view of a second tooth of the in Fig. 1. Bicycle sprocket shown. Fig. 15 is an enlarged side view of the first and second teeth of the in Fig. 1. Bicycle sprocket shown. Fig. Figure 16 is a schematic diagram showing an inclination or angulation / skew of a bicycle chain, engaging with the bicycle sprocket arrangement and another sprocket arrangement. Fig. Figure 17 shows a partial side view of the bicycle sprocket. Fig. 1 with the bicycle chain. Fig. Figure 18 shows a top view of the bicycle sprocket. Fig. 1 with the bicycle chain. Fig. Figure 19 is an enlarged side view of a second tooth of the bicycle sprocket in accordance with a second embodiment. DESCRIPTION OF THE EXECUTION FORMS

[0035] The embodiments are now explained with reference to the attached drawings, whereby the same reference numerals denote corresponding or identical elements throughout the different drawings. First embodiment

[0036] Initially referring to Fig. Figure 1 comprises a bicycle sprocket assembly 10 and a bicycle sprocket 12 in accordance with a first embodiment. The bicycle sprocket 12 has a rotational center axis A1. The bicycle sprocket 12 is rotatable about the rotational center axis A1 with respect to a bicycle frame (not shown). The bicycle sprocket 12 engages with a bicycle chain BC to transmit a rotational driving force F1 to the bicycle chain BC. In this embodiment, the bicycle sprocket 12 is a single sprocket without any other sprocket in the bicycle sprocket assembly. However, the bicycle sprocket assembly 10 can include another sprocket in addition to the bicycle sprocket 12. Furthermore, the bicycle sprocket 10 is a front sprocket assembly or a front chainring assembly. However, the structures of the bicycle sprocket assembly 10 can be applied to a rear sprocket assembly.

[0037] In the present application, the following directional terms, "front," "rear," "in front," "back," "left," "right," "across," "above," "below," and any similar directional terms, refer to directions defined on the basis of a user (e.g., a cyclist) sitting on a bicycle saddle (not shown), facing a handlebar (not shown). According to these terms, as used here to describe the bicycle sprocket 12 of the bicycle sprocket assembly 10, they shall be interpreted in relation to the bicycle equipped with the bicycle sprocket 12, in an upright riding position on a horizontal surface.

[0038] As can be seen in Fig. 1 and Fig. In this embodiment, the bicycle sprocket 12 further comprises a crank mounting part 14 for coupling the sprocket body 18 to a bicycle crank 16. The bicycle sprocket assembly 10 further comprises a crank arm 16. The bicycle crank 16 comprises a crank axle 16A, a right crank arm 16B, a left crank arm 16C, and connecting arms 16D. The crank mounting part 14 has crank mounting sections 14A. The crank connecting arms 16D are each attached to the crank mounting sections 14A by fasteners such as screws (not shown).

[0039] The right crank arm 16B and the left crank arm 16C are secured to the crank axle 16A. The right crank arm 16B and the left crank arm 16C are rotatably mounted to the bicycle frame around the central axis of rotation A1 via the crank axle 16A. The crank mounting part 14 is coupled to the right crank arm 16B via the connecting arms 16D in such a way that it is integrally rotatable with the right crank arm 16B around the central axis of rotation A1. The crank mounting part 14 can also be integrally provided with the right crank arm 16B as a single, unitary element. Specifically, the bicycle sprocket 12 is integrally rotatable with the crank mounting part 14 and the right crank arm 16B around the central axis of rotation A1. The bicycle sprocket 12 is rotatable around the central axis of rotation A1 in a drive direction D11 during pedaling.The drive rotation direction D11 is defined along a circumferential direction D1, which is defined around the rotation center axis A1.

[0040] As can be seen in Fig. 1 and Fig. The bicycle sprocket assembly 12 comprises a sprocket body 18 and a plurality of chain drive teeth 20. The sprocket body 18 has a radial outer circumference 22, which is provided around the rotational center axis A1 of the bicycle sprocket 12. The sprocket body 18 has a radial inner circumference 23, which is provided around the rotational center axis A1. The radial outer circumference 22 is provided radially outside of the radial inner circumference 23. The crank mounting part 14 extends radially inward from the radial inner circumference 23.

[0041] The plurality of chain drive teeth 20 are provided on the radial outer circumference 22 to engage with the bicycle chain BC. The plurality of chain drive teeth comprises a first tooth 24 and a second tooth 26. In this embodiment, the plurality of chain drive teeth 20 comprises a plurality of first teeth 24 and a plurality of second teeth 26. The total number of first teeth 24 is equal to the total number of second teeth 26. The total number of first teeth 24 and the total number of second teeth 26 are not limited in this embodiment. The first teeth 24 and the second teeth 26 are arranged alternately in the circumferential direction D1. However, the arrangement of the first and second teeth 26 is not limited to this embodiment. The first tooth 24 has a different shape than the second tooth 26.

[0042] As can be seen in Fig. From 3 to 6, the first tooth 24 has a lagging circumferential surface 28 (a first lagging circumferential surface 28) and a leading circumferential surface 30 (a first leading circumferential surface 30). The lagging circumferential surface 28 points in a drive rotation direction D11, in which the bicycle sprocket 12 rotates around the central axis of rotation A1 during pedaling. The drive rotation direction D11 is the direction in which the bicycle sprocket 12 rotates to transmit a pedal force from the bicycle sprocket 12 to the bicycle chain BC during pedaling, in order to move a bicycle equipped with the bicycle sprocket assembly 10 forward. The leading circumferential surface 30 points in a counter-rotation direction D12, which is opposite to the drive rotation D11.

[0043] The second tooth 26 has a lagging circumferential surface 32 (a second lagging circumferential surface 32) and a leading circumferential surface 34 (a second leading circumferential surface 34). The lagging circumferential surface 32 faces D11 in the direction of drive, in which the bicycle sprocket 12 rotates around the axis of rotation A1 during pedaling. The leading circumferential surface 34 faces D12 in the opposite direction of rotation to the direction of drive rotation D11.

[0044] As can be seen in Fig. The first tooth 24 has a symmetrical shape with respect to an axial midplane CP3, which is perpendicular to the axis of rotation A1. The second tooth 26 also has a symmetrical shape with respect to the axial midplane CP3. However, at least one of the first tooth 24 and one of the second tooth 26 may have an asymmetrical shape with respect to the axial midplane CP3.

[0045] The bicycle sprocket 12 comprises a first side surface S1 and a second side surface S2, opposite the first side surface S1 in an axial direction D2 parallel to the axis of rotation A1. In this embodiment, the second side surface S2 is closer to the bicycle frame (not shown) than the first side surface S1 in the axial direction S2. Consequently, the first side surface S1 is an axially outer side surface and the second side surface S2 is an axially inner side surface in a state in which the bicycle sprocket assembly 10 is mounted on the bicycle frame. However, the first side surface can be closer to the bicycle frame (not shown) than the second side surface S2 in the axial direction S2.

[0046] As can be seen in Fig. 8 and Fig. 9, the first tooth 24 has a first maximum chain engagement width W1, defined in an axial direction D2 parallel to the axis of rotation A1. The first maximum chain engagement width W1 is larger than an inner link space BC11, defined between an opposing pair of inner link plates BC1 of the bicycle chain BC and smaller than an outer link space BC21, defined between an opposing pair of outer link plates BC2 of the bicycle chain BC.

[0047] As can be seen in Fig. The first tooth 24 has a first axial surface 24A to engage with one of the opposite pair of outer link plates BC2. The first axial surface 24A may have a first chain-guiding area that points towards the outer link plate BC2 in the axial direction D2 during pedaling. The first tooth 24 has a first further axial surface 24B, arranged opposite the first axial surface 24A, to engage with the other of the opposite pair of outer link plates BC2. The first further axial surface 24B may have a first further chain-guiding area that points towards the outer link plate BC2 in the axial direction D2 during pedaling. The first maximum chain engagement width W1 is defined between the first axial surface 24A and the second further axial surface 24B in the axial direction D2.More precisely, the first maximum chain engagement width W1 can be defined as an axial width between an axially outermost endpoint of the first chain-providing region and an axially innermost endpoint of the first further chain-providing region in the axial direction D2. The first axial surface 24A is closer to the first side surface S1 than the first further axial surface 24B in the axial direction D2. The second axial surface 24A is closer to the first side surface S1 than the second further axial surface 24B in the axial direction D2.

[0048] As can be seen in Fig. 9. The second tooth 26 has a second maximum chain engagement width W2, defined in the axial direction D2. The second maximum chain engagement width W2 is smaller than the inner link space BC11. The second tooth 26 has a second axial surface 26A to engage with one of the opposite pair of inner link plates BC1. The second axial surface 26A may have a second chain-guiding area facing the inner link plate BC1 in the axial direction D2 during pedaling. The second tooth 26 has a second further axial surface 26B, arranged opposite the second axial surface 26A, to engage with the other of the opposite pair of outer link plates BC2. The second further axial surface 26B may have a second further chain-guiding area facing the inner link plate BC1 in the axial direction B2 during pedaling.The second maximum chain engagement width W2 is defined between the second axial surface 26A and the second further axial surface 26B in the axial direction D2. More precisely, the second maximum chain engagement width W2 can be defined as an axial width between an axially outermost endpoint of the second chain-guiding area and an axially innermost endpoint of the second further chain-guiding area in an axial direction D2. The first axial surface 24A and the second axial surface 26A serve as a chain engagement surface to engage with the bicycle chain BC.

[0049] As can be seen in Fig. In section 9, the axial midplane CP3 is defined as an axial center of the first axial surface 24A and the first further axial surface 24B. The axial midplane CP3 can also be defined as an axial center of the second axial surface 26A and the second further axial surface 26B. In particular, the second axial surface CP3 is a surface perpendicular to the axis of rotation A1. The axial midplane CP3 extends through a center CW1 of the first maximum chain engagement width W1 and extends through a center CW2 of the second maximum chain engagement width W2. The axial midplane CP3 extends through a center CA1 of a line connecting an axially outermost end of the first axial surface 24A with an axially outermost end of the first further axial surface 24B. The second axial midplane CP3 extends through a center CA2 of a line connecting an axially outermost end of the second axial surface 26A with an axially outermost end of the second further axial surface 26B.In this embodiment, the axial center plane of the first tooth 24 coincides with the axial center plane of the second tooth 26. However, the axial center plane of the first tooth 24 may be spaced apart from the axial center plane of the second tooth 26 in the axial direction D2 (one from the inside and one from the outside). Furthermore, in this embodiment, although the axial center plane of the first tooth 24 coincides with the axial center plane of a first radially outermost end 24C (described below), these may be spaced apart from each other in the axial direction B2. Likewise, although the axial center plane of the second tooth coincides with an axial center plane of a second radially outermost end 26C (described below), these may be spaced apart from each other in the axial direction D2.

[0050] As can be seen in Fig. 10 and Fig. In the bicycle sprocket 12, a reference line RL1 is defined as a line connecting the centers BC31 of adjacent pins BC3 of the bicycle chain BC, engaged with the plurality of chain drive teeth 20, when viewed from the axial direction D2. The reference line RL1 is a circular arc defined with respect to the bicycle sprocket 12 on a rolling circle diameter, defined based on the centers BC31 of the adjacent pins BC3 of the bicycle chain BC, in a state where the bicycle chain BC is fully engaged with the plurality of chain drive teeth 20. The reference line RL1 can be defined based on the centers BC41 of rollers BC4. The centers BC41 of the rollers BC4 coincide with the centers BC31 of the pins BC3.The bicycle chain BC is fully engaged with the multitude of chain drive teeth 20 in a state in which the roller BC4 is arranged between the first tooth 24 and the second tooth 26 in a position closest to the axis of rotation A1.

[0051] The roller BC4 of the bicycle chain BC is spaced from the reference line RL1 when the roller BC4 begins to disengage from the plurality of chain drive teeth 20. A center point P1 is defined as the center point of the reference line RL1 between an intersection point P21 of the reference line RL1 and the first lagging circumferential surface 28, and an intersection point P22 of the reference line RL1 and the first leading circumferential surface 30, when viewed from the axial direction D2. In this embodiment, for example, the chain pitch BC5 of the bicycle chain BC is 12.7 mm and the outer diameter BC42 of the roller BC4 is 7.65 mm. However, the chain pitch BC5 and the outer diameter BC42 of the roller BC4 are not limited to this embodiment.

[0052] As can be seen in Fig. 10 and Fig. In section 11, the first tooth 24 has a circumferential median plane CP1 extending radially from the axis of rotation A1 through a midpoint P1 of the reference line RL1. The circumferential median plane CP1 is parallel to the axis of rotation A1. The lagging circumferential surface 28 is located on a lagging side of the circumferential median plane CP1 in the direction of drive rotation D11. The leading circumferential surface 30 is located on a leading side of the circumferential median plane CP1 in the direction of drive rotation D11.

[0053] The second tooth 26 has a circumferential center plane CP2 extending radially from the center of rotation A1 through the midpoint P1 of the reference line RL1. The circumferential center plane CP2 is parallel to the axis of rotation A1. The lagging circumferential surface 32 is located on a lagging side of the circumferential center plane CP2 in the drive direction B11. The leading circumferential surface 34 is located on a leading side of the circumferential center plane CP2 in the drive rotation direction D11.

[0054] Fig. Figure 8 is a sectional view seen along the axial midplane CP3. As can be seen in Fig. In embodiment 8, the first tooth 24 has a first width W11, defined in the axial direction D2. The first width W11 is defined at the reference position RP11, radially outward from the midpoint P1 of a reference line RL1 by 1.5 mm. The first width W11 is 70% or more of the first maximum chain engagement width W1. The first width W11 is preferably 80% or more of the first maximum chain engagement width W1. The first width W11 is particularly preferably 90% or more of the first maximum chain engagement width W11. However, the ratio between the first width W11 and the first maximum chain engagement width W1 is not limited to this embodiment. For example, the first width W11 can be approximately 70% or more of the first maximum chain engagement width W11. The first width W11 can be approximately 80% or more of the first maximum chain engagement width W1. The first width W11 can be approximately 90% or more of the first maximum chain engagement width W1.In this embodiment, the first width is 91.8% of the first maximum chain engagement width 91.8% W1.

[0055] The first tooth 24 has a second width W12, defined in the axial direction D2. The second width W12 is defined at a reference position RP12, radially outward from the midpoint P1 of the reference line RL1 by 1.0 mm. The second width W12 is 80% or more of the first maximum chain engagement width W1. The second width W12 is preferably 90% or more of the first maximum chain engagement width W1. The second width W12 is particularly preferably 95% or more of the first maximum chain engagement width W1. In this embodiment, the second width W12 is equal to the first maximum chain engagement width W1 (i.e., the second width W12 is 100% of the first maximum chain engagement width W1). However, the second width W12 is not limited to this embodiment. For example, the second width W12 can be approximately 80% or more of the first maximum chain engagement width W1. The second W12 can be approximately 90% of the first maximum chain engagement width W1.The second width W12 can be approximately 35% or more of the first maximum chain engagement width W1.

[0056] As can be seen in Fig. 8 is the first maximum chain engagement width W1 defined at a reference position RP13, radially outward from the center point P1 of the reference line RL1 by 0.5 mm. In other words, the first tooth 24 has a third width W13, defined in the axial direction D2. The third width W13 is defined at the reference position RP13 and is 100% of the maximum chain engagement width W1. However, the first maximum chain engagement width W1 is not limited to this embodiment. For example, the first maximum chain engagement width W1 can be defined at a different reference position than reference position RP12 or at a position radially inward from reference position RP13, such as reference line PL1.

[0057] The first tooth 24 has a first radially outermost end 24C. The first radially outermost end 24C is further radially outward from the radially outer circumference 22 of the pinion body 18 than the first axial surface 24A. The first radially outermost end 24C is further radially outward from the radially outermost circumference 22 of the pinion body 18 than the first further axial surface 24B. In this embodiment, the first radially outermost end 24C is the radially furthest point of the first tooth 24 from the radial outer circumference 22 of the pinion body 18.

[0058] As can be seen in Fig. A minimum axial distance L11 is defined between the first axial surface 24A and the first radially outermost end 24C in the axial direction D2 and is less than or equal to 0.8 mm. More precisely, the minimum axial distance L11 is defined between an axially outermost endpoint 24A1 of the first chain-providing region of the first axial surface 24A and an axially outermost endpoint 24C1 of the first radially outermost end 24C. In this embodiment, the center point P1 can, for example, be defined on the first axial surface 24A as the axially outermost endpoint of the first chain-providing region of the first axial surface 24A. A further minimum axial distance L12 is defined between the first further axial surface 24B and the first radially outermost end 24C in the axial direction D2 and is equal to or less than 0.8 mm.The minimum axial distance L12 is defined, for example, between an axially innermost endpoint 24B1 of the first further chain-wise region of the first further axial surface 24B. However, the minimum axial distance L11 and the further minimum axial distance L12 are not limited to this embodiment. For example, the minimum distance L11, which is defined between the first axial surface 24A and the first radially outermost end 24C in the axial direction D2, can be equal to or less than approximately 0.8 mm. The further minimum axial distance L12, defined between the first further axial surface 24B and the first radially outermost end 24C in the axial direction B2, can be equal to or less than approximately 0.8 mm.

[0059] The first tooth 24 has a first inclined or angled surface 24D extending between the first axial surface 24A and the first radially outermost end 24C. The first inclined surface 24D is inclined with respect to the axial direction D2 to form a maximum angle AG11 between the first inclined surface 24D and the first axial surface 24A. The maximum angle AG11 is equal to or less than 25 degrees. However, the maximum angle AG11 is not limited to this in this embodiment. For example, the maximum angle AG11 can be equal to or less than approximately 25 degrees.

[0060] As can be seen in Fig. 8 and Fig. In the first tooth 24, a coupling surface 24E is provided, coupling the first inclined surface 24D with the first axial surface 24A. The coupling surface 24E has a curved surface extending between the first inclined surface 24D and the first axial surface 24A. However, the shape of the coupling surface 24E is not limited to this embodiment and can be of a different shape, such as a flat surface. The coupling surface 24E has a center 24E1 defined between the first inclined surface 24D and the first axial surface 24A when viewed from the axial direction D1. The center 24E1 of the coupling surface 24E is arranged radially outward from the reference line RL1 at a radial distance LE1, which is equal to or greater than 0.5 mm. The center 24E1 of the coupling surface 24E is preferably arranged in a position radially outwardly spaced from the reference RL1 by 1.0 mm or more. However, the position of the center 24E1 of the coupling surface 24E is not limited to this embodiment.For example, the center E1 of the coupling surface 24E can be arranged radially outward from the reference line RL1 by a radial distance equal to or greater than approximately 0.5 mm. The center 24E1 of the coupling surface 24E can be arranged in a position radially outward from the reference line RL1 by approximately 0.1 mm or more.

[0061] The first tooth 24 has a first radial length RL1, radially defined from the reference line RL1 to the first radially outermost end 24C. The first radial length L1 is equal to or greater than 3.0 mm. The first radial length L1 is preferably equal to or less than 4.0 mm. However, the first radial length L1 is not limited to this embodiment. For example, the first radial length L1 can be equal to or greater than approximately 3.0 mm. The first radial length L1 can be equal to or less than approximately 4.0 mm.

[0062] As can be seen in Fig. In the first tooth 24, a first further inclined surface 24F extends between the first further axial surface 24B and the first radially outermost end 24C. The first further inclined surface 24F is inclined or angled with respect to the axial direction B2 to define a maximum angle AG12 between the first further inclined surface 24F and the first further axial surface 24B. The maximum angle AG12 is equal to or less than 25 degrees. However, the maximum angle AG12 may be limited to this embodiment. For example, the maximum angle AG12 may be equal to or less than 25 degrees. In this embodiment, the maximum angle AG11 and the maximum angle AG12 are equal to each other. However, the maximum angle AG11 may differ from the maximum angle AG12.

[0063] As can be seen in Fig. In the first tooth 24, a further coupling surface 24E couples the first further inclined surface 24F to the first axial surface 24A. The further coupling surface 24G has a curved surface extending between the first further inclined surface 24F and the first axial surface 24A. However, the shape of the further coupling surface 24G is not limited to this embodiment and can have a different shape, such as a flat surface. The further coupling surface 24G has a center 24G1, defined between the first further inclined surface 24E and the first axial surface 24A, when viewed from the axial direction D2. The center 24G1 of the further coupling surface 24G is arranged radially outward from the reference line RL1 by a radial distance LG1, which is equal to or greater than 0.5 mm. The center 24G1 of the further coupling surface 24G is preferably arranged in a position radially outwardly spaced from the reference line RL1 by 1.0 mm or more.However, the position of the center 24G1 of the further coupling surface 24G is not limited to this embodiment. For example, the center 24G1 of the further coupling surface 24G can be arranged radially outward from the reference line RL1 by a radial distance equal to or greater than 0.5 mm. The center 24G1 of the further coupling surface 24G can be arranged in a position radially outward from the reference line RL1 by approximately 1.0 mm or more.

[0064] As can be seen in Fig. In this embodiment, the second tooth 26 has a second radially outermost end 26C. The second radially outermost end 26C is further radially outward from the radial outer circumference 22 of the pinion body 18 than the second axial surface 26A. The second radially outermost end 26C is further radially outward from the radial outer circumference of the pinion body 18 than the second axial surface 26B. In this embodiment, the second radially outermost end 26C is the radially furthest point of the second tooth 26 from the radial outer circumference 22 of the pinion body 18.

[0065] The second tooth 26 has a second radial length L2, radially defined from the reference line RL1 to the second radially outermost end 26C. The second radial length L2 is in the range of 1.5 mm to 2.9 mm. The second radial length L2 is preferably in the range of 2.0 mm to 2.5 mm. The second radial length L2 is preferably in the range of 2.5 mm to 2.9 mm. However, the second radial length L2 is not limited to this embodiment. For example, the second radial length L2 can be in the range of approximately 1.5 mm to approximately 2.9 mm. The second radial length L2 can be in the range of approximately 2.0 mm to approximately 2.5 mm. The second radial length L2 can be in the range of approximately 2.5 mm to approximately 2.9 mm.

[0066] In this embodiment, as can be seen in Fig. 15, the first radial length L1 is greater than the second radial length L2. However, the first radial length L1 can be equal to or less than the second radial length L2. A difference between the first radial length L1 and the second radial length L2 is equal to or less than 1.5 mm. A difference between the first radial length L1 and the second radial length L2 is preferably equal to or less than 1.0 mm. However, the difference between the first radial length L1 and the second radial length L2 is not limited to this embodiment. For example, the difference between the first radial length L1 and the second radial length L2 can be equal to or less than approximately 1.5 mm. The difference between the first radial length L1 and the second radial length L2 can be equal to or less than approximately 1.0 mm.

[0067] As can be seen in Fig. In the second tooth 26, a shortest distance L3 is defined between the lagging circumferential surface 32 and a first intersection point P21 of the circumferential median plane CP2 and a further reference line RL2. More precisely, a line LP21 is defined to extend through the first intersection point P21 and to be perpendicular to the circumferential median plane CP2 when viewed from the axial direction D2. The line LP21 intersects the lagging circumferential surface 32 at a lag point 32A. The shortest distance L3 is defined from the first intersection point P21 to the lag point 32A. The shortest distance L3 is equal to or greater than 2.0 mm. However, the shortest distance L3 is not limited to this embodiment. For example, the shortest distance L3 can be equal to or greater than approximately 2.0 mm.

[0068] The second reference line RL 2 is defined in a reference position radially outward from reference line RL 1 by 1.5 mm. More precisely, the second reference line RL 2 is a circular arc located radially outward from reference line RL 1 by 1.5 mm and sharing the same center (the axis of rotation A1) as reference line RL 1. However, the position of the second reference line RL 2 is not limited to this embodiment. For example, the second reference line RL 2 could be defined in a reference position radially outward from reference line RL 1 by approximately 1.5 mm.

[0069] The second tooth 26 has a further shortest distance L4, defined between the circumferential center plane CP2 and the leading circumferential surface 34 at the further reference line RL2. More precisely, the line LP 21 intersects the leading circumferential surface 34 at a leading point 34A. The further shortest distance L4 is defined from the first intersection point P21 to the first leading point 34A. The further shortest distance L4 is less than 2.0 mm. However, the further shortest distance L4 is not limited to this embodiment. For example, the further shortest distance L4 can be less than approximately 2.0 mm. In this embodiment, the further shortest distance L4 is approximately the same as the shortest distance L3.

[0070] As can be seen in Fig. 14 The second tooth 26 has a lagging coupling surface 26D and a leading coupling surface 26E. The lagging coupling surface 26D extends between the second lagging circumferential surface 32 and the second radially outermost end 26C. The leading coupling surface 26E extends between the second leading circumferential surface 34 and the second radially outermost end 26C.

[0071] The lagging connecting surface 26D has a center point MP1, defined between the lagging circumferential surface 32 and the second radially outermost end 26C, when viewed from the axial direction D2. For example, center point MP1 is a center point of the lagging connecting surface 26D when viewed from the axial direction D2. The leading connecting surface 26E has a center point MP2, defined between the leading circumferential surface 34 and the second radially outermost end 26C, when viewed from the axial direction D2. For example, center point MP2 is a center point of the leading connecting surface 26E when viewed from the axial direction D2. In this embodiment, the lagging connecting surface 26D has a curved surface with a center C1 of a circular arc. The leading connecting surface 26E has a curved surface with a center C2 of a circular arc.However, the shapes of the lagging connecting surface 26D and the leading connecting surface 26E are not limited to this embodiment.

[0072] As can be seen in Fig. 14. An inclined reference line RL3 is defined between the midpoint MP1 of the trailing connecting surface 26D and a second intersection point P22 of the circumferential center plane CP2 and the reference line RL1, when viewed from the axial direction D2. A helix angle AG3, defined between the circumferential center plane CP2 and the inclined RL3, is in a range of 32 degrees to 52 degrees when viewed from the axial direction D2, if the second radial length L2 is in a range of 2.0 mm to 2.5 mm. The helix angle AG3 is defined between the circumferential center plane CP2 and the inclined reference line RL3 and is preferably in a range of 29 degrees to 36.4 degrees when viewed from the axial direction D2, if the second radial length L2 is in a range of 2.5 mm to 3.0 mm.

[0073] However, the helix angle AG3 is not limited to this embodiment. The helix angle AG3, defined between the circumferential center plane CP2 and the inclined reference line RL3, can be in a range of approximately 32 degrees to approximately 52 degrees when viewed from the axial direction D2. The helix angle AG3, defined between the circumferential center plane CP2 and the inclined reference line RL3, can be in a range of approximately 29 degrees to approximately 36.4 degrees when viewed from the axial direction D2.

[0074] As can be seen in Fig. The first tooth 24 has recesses 24H1, 24H2, 24H3, and 24H4 on teeth 3 to 6 to reduce interference between the first tooth 24 and the inner link plate BC1 of the bicycle chain BC2. Recess 24H1 is located between the trailing circumferential surface 28 and the first axial surface 24A. Recess 24H2 is located between the leading circumferential surface 30 and the first axial surface 24A. Recess 24H3 is located between the trailing circumferential surface 28 and the first subsequent axial surface 24B. Recess 24H4 is located between the leading circumferential surface 30 and the first subsequent axial surface 24B. At least one of the recesses 24H1, 24H2, 24H3, and 24H4 can be omitted from the first tooth 24. Furthermore, the second tooth 26 does not exhibit a regression like the regressions 24H1, 24H2, 24H3, and 24H4. However, the second tooth 26 can exhibit regressions like the regressions 24H1, 24H2, 24H3, and 24H4.

[0075] As can be seen in Fig. 14 defines the shortest distance L3 between the lagging circumferential surface 28 and the first intersection point P21 of the circumferential center plane CP2 and the further reference line RL2. The shortest distance L3 is equal to or greater than 2.0 mm. The further reference line RL2 is defined at the reference position radially outward from the reference line RL1 by 1.5 mm. Consequently, it is possible to provide earlier timing at which the second tooth 26 engages the opposite pair of inner link plates BC1 of the bicycle chain BC. Therefore, it is possible to smoothly engage the second tooth 26 with the opposite pair of inner link plates BC1, even if the bicycle chain BC is at a significant angle relative to the bicycle sprocket 12, as viewed from above the bicycle sprocket 12. This can improve the chain retention performance of the bicycle sprocket 12.

[0076] For example, as can be seen in Fig. In Figure 16, the bicycle chain BC is sharply angled with respect to the axial center plane CP3 of the bicycle sprocket 12 in a state where the bicycle chain BC is engaged with the largest rear sprocket RS1 or a smallest rear sprocket RS2. As can be seen in Fig. 17 and Fig. In the first tooth 24X, the second tooth 26X is inserted between the opposing pair of inner link plates BC1X in a state where the opposing pair of outer link plates BC2X are held by the first tooth 24X. Since the shortest distance L3 is equal to or less than 2.0 mm, it is possible to provide earlier timing in which the second tooth 26X engages the opposing pair of inner link plates BC1X. Consequently, it is possible to smoothly engage the second tooth 26X with the opposing pair of inner link plates BC1X, even if the bicycle chain BC is at a significant angle relative to the bicycle sprocket 12, when viewed from above the bicycle sprocket 12. This can improve the chain retention performance of the bicycle sprocket 12. Second embodiment

[0077] A bicycle sprocket assembly 210 comprising a bicycle sprocket 212 in accordance with a second embodiment is described below with reference to Fig. 19 described. The bicycle sprocket 212 has the same structure as that of the bicycle sprocket 12, except for the second tooth 26. Accordingly, elements which have essentially the same function as those of the first embodiment are given the same reference numerals here and are not described or shown further for the sake of brevity.

[0078] As can be seen in Fig.In the bicycle sprocket 212, the plurality of chain drive teeth 20 has a second tooth 226. The second tooth 226 has essentially the same structure as the second tooth 26 of the first embodiment. However, unlike the second tooth 26, the trailing connecting surface 26D of the second tooth 226 is radially further outward from the reference line RL1 than the leading connecting surface 26E. The center point MP1 of the trailing connecting surface 26E is radially further outward from the reference line RL1 than the center point MP2 of the leading connecting surface 26E. The second radially outermost end 26D is angled to create a gradually decreasing radial distance, which is defined between the second radially outermost end 26D and the reference line RL1 from the trailing connecting surface 26D to the leading connecting surface 26E.

[0079] With the bicycle sprocket arrangement 210 and the bicycle sprocket 212, it is possible to achieve essentially the same effects as with the bicycle sprocket arrangement 10 and the bicycle sprocket 12 of the first embodiment.

[0080] The term "encompass" and its derivatives, as used here, are to be understood as open terms that specify the presence of the mentioned features, elements, components, groups, integers, and / or steps, but do not exclude the presence of other unmentioned features, elements, components, groups, integers, and / or steps. The above also applies to words with similar meanings, such as "exhibit," "with," "have," and their derivatives.

[0081] The terms “part”, “section”, “section”, “link” or “element”, when used in the singular, can have the plural meaning of a single part or a multitude of parts.

[0082] The ordinal numbers, such as "first" and "second," as used in the present application, are merely identifiers and have no other meaning, such as indicating a specific sequence or the like. Furthermore, the term "first element," for example, does not imply the existence of a "second element," and the term "second element" does not imply the existence of a "first element."

[0083] The term “pair of” as used herein may include the configuration in which the pair of elements have different shapes or structures from each other, in addition to the configuration in which the pair of elements have the same shapes or structures.

[0084] Finally, the magnitude terms, such as "essentially", "by" and "approximately", as used herein, signify a reasonable amount of deviation of the modified term so that the final result is not significantly altered.

[0085] Obviously, a multitude of modifications and variations of the present invention are possible in light of the teaching described above. Therefore, within the scope of the attached claims, it should be understood that the present invention can be implemented differently than specifically described herein.

Claims

[1] Bicycle sprocket (12; 212) comprising: a pinion body (18) having a radial outer circumference (22) provided around a rotational center axis (A1) of the bicycle sprocket (12; 212); and a plurality of chain drive teeth (20) provided on the radial outer circumference (22) to engage with a bicycle chain (BC), the plurality of chain drive teeth (20) comprising: a first tooth (24), having a first maximum chain engagement width (W1), defined in an axial direction (D2) parallel to the axis of rotation (A1), wherein the first tooth (24) has a first radially outermost end (24C) radially furthest from the radial outer circumference (22) of the pinion body (18), wherein the first tooth (24) has a first radial length (L1) radially defined from a reference line (RL1) to the first radially outermost end (24C); and a second tooth (26; 226) with a second maximum chain engagement width (W2), defined in the axial direction (D2), wherein the first maximum chain engagement width (W1) is larger than an inner link space (BC11), defined between an opposing pair of inner link plates (BC1; BC1X) of the bicycle chain (BC) and smaller than an outer link space (BC21), defined between an opposing pair of outer link plates (BC2; BC2X) of the bicycle chain (BC), wherein the second maximum chain engagement width (W2) is smaller than the inner link space (BC11), and wherein the second tooth (26; 226) has a second radially outermost end (26C), radially furthest from the radial outer circumference (22) of the sprocket body (18), wherein the second tooth (26; 226) has a second radial length (L2), radially defined from the reference line (RL1) to the second radially outermost end (26C), wherein the second radial length (L2) is in a range of 1.5 mm to 2.9 mm, and wherein the second tooth (26; 226) has a circumferential mean plane (CP2) extending radially from the rotation mean axis (A1) through a midpoint (P1) of a reference line (RL1), wherein the reference line (RL1) is defined to connect centers (BC31) of pins BC3) of the bicycle chain (BC) which engages with the plurality of chain drive teeth (20), and wherein a trailing circumferential surface (32) has in a drive rotation direction (D11) in which the bicycle sprocket (12; 212) rotates around the rotation center axis (A1) during pedaling, wherein the trailing circumferential surface (32) is arranged on a trailing side of the circumferential center plane (CP2) in the drive rotation direction (D11), and a shortest distance (L3) defined between the lagging circumferential surface (32) and a first intersection point (P21) of the circumferential mean plane (CP2) and a further reference line (RL2), wherein the shortest distance (L3) is equal to or greater than 2.0 mm and wherein the further reference line (RL2) is defined at a reference position (RP11; RP12; RP13) spaced radially outward from the reference line (RL1) by 1.5 mm. [2] Bicycle sprocket (12; 212) according to claim 1, wherein the first radial length (L1) is greater than the second radial length (L2), preferably one or more of the following conditions are met: a) the second radial length (L2) is in a range of 2.0 mm to 2.5 mm; b) the second radial length (L2) in a range of 2.5 mm to 2.9 mm; c) the difference between the first radial length (L1) and the second radial length (L2) is less than or equal to 1.5 mm; d) the difference between the first radial length (L1) and the second radial length (L2) is less than or equal to 1.0 mm; e) the first radial length (L1) is equal to or greater than 3.0 mm; f) the first radial length (L1) is equal to or less than 4.0 mm. [3] Bicycle sprocket (12; 212) according to one of claims 1 or 2, wherein the second tooth (26; 226) has a leading circumferential surface (34) pointing in a counter-rotation direction (D12), opposite to the drive rotation direction (D11), wherein the leading circumferential surface (34) is arranged on a leading side of the circumferential median plane (CP2) in the drive rotation direction (D11), and has a further shortest distance (L4) defined between the circumferential mean plane (CP2) and the leading circumferential surface (34) at the further reference line (RL2), wherein the further shortest distance (L4) is less than 2.0 mm. [4] Bicycle sprocket (12; 212) according to claim 1 or 2, wherein the second tooth (26; 226) has a lagging connecting surface (26D) extending between the lagging circumferential surface (32) and the second radially outermost end (26C), a leading circumferential surface (34), pointing in a counter-rotation direction (D12), opposite to the drive rotation direction (D11), wherein the leading circumferential surface (34) is arranged on a leading side of the circumferential median plane (CP2) in the drive rotation direction (D11), and a leading connecting surface (26E) extending between the leading circumferential surface (34) and the second radially outermost end (26C), and the lagging connection surface (26D) is further radially outward from the reference line (RL1) than the leading connection surface (26E). [5] Bicycle sprocket (12; 212) according to claim 2 or 3, wherein, if the second radial length (L2) is in a range of 2.0 mm to 2.5 mm, the second tooth (26; 226) has a lagging connecting surface (26D) extending between the lagging circumferential surface (32) and the second radially outermost end (26C), wherein the lagging connecting surface (26D) has a center point (MP1) defined between the lagging circumferential surface (32) and the second radially outermost end (26C) when viewed from the axial direction (D2), a slanted reference line (RL3) is defined between the midpoint (MP1) of the lagging connecting surface (26D) and a second intersection point (P22) of the circumferential mean plane (CP2) and the reference line (RL1), when viewed from the axial direction (D2), and a skew angle (AG3) is defined between the circumferential mean plane (CP2) and the skew reference line (RL3) in a range of 32 degrees to 52 degrees when viewed from the axial direction (D2). [6] Bicycle sprocket (12; 212) according to one of claims 2 or 3, wherein, if the second radial length (L2) is in a range of 2.5 mm to 2.9 mm, the second tooth (26; 226) has a trailing connecting surface (26D) extending between the trailing circumferential surface (32) and the second radially outermost end (26C), wherein the trailing connecting surface (26D) has a center point (MP1) defined between the trailing circumferential surface (32) and the second radially outermost end (26C) when viewed from the axial direction (D2), an oblique reference line (RL3) is defined between the center point (MP1) of the trailing connecting surface (26D) and a second intersection point (P22) of the circumferential median plane (CP2) and the reference line (RL1) when viewed from the axial direction (D2), and a skew angle (AG3) is defined between the circumferential mean plane (CP2) and the skew reference line (RL3) in a range of 29 degrees to 36.4 degrees when viewed from the axial direction (D2). [7] Bicycle sprocket (12; 212) according to claim 4, 5 when dependent on 3 or 6, when dependent on claim 3, wherein the trailing connecting surface (26D) has a center point (MP1) defined between the trailing circumferential surface (32) and the second radially outermost end (26C) when viewed from the axial direction (D2), the leading connecting surface (26E) has a center point (MP2) defined between the leading circumferential surface (34) and the second radially outermost end (26C) when viewed from the axial direction (D2), and the center point (MP1) of the lagging connecting surface (26D) is radially further outwards from the reference line (RL1) than the center point (MP2) of the leading connecting surface (26E). [8] Bicycle sprocket (12; 212) according to one of claims 1 to 7 further comprising a crank attachment part (14) to couple the sprocket body (18) to a bicycle crank (16). [9] Bicycle sprocket arrangement (10; 210) comprising: the bicycle sprocket (12; 212) according to one of claims 1 to 8, wherein the bicycle sprocket (12; 212) is a single sprocket without a further sprocket in the bicycle sprocket arrangement (10; 210).

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