TW202100402A - Bicycle driving system and bicycle front sprocket assembly can suppress chain from coming off and have excellent driving efficiency - Google Patents

Abstract

To provide a bicycle driving system and a bicycle front sprocket assembly that can smoothly change the gear ratio in a wide range. The driving system includes: a crank assembly, and a composite rear sprocket assembly including multiple rear sprockets. The crank assembly includes: a front sprocket, a crank arm, and a sprocket teeth displacement mechanism that allows the sprocket teeth of the front sprocket to be displaced relative to the crank arm in the axial direction of the rotation center axis of the front sprocket. The plurality of rear sprockets include: the smallest rear sprocket, the largest rear sprocket, and at least twelve intermediate rear sprockets arranged between the two sprockets. The length between the axial outer surface of the smallest rear sprocket and the axial inner surface of the largest rear sprocket in the axial direction is defined as the axial length, and the axial length is more than 47.5 mm.

Description

Drive system for bicycle and front sprocket assembly for bicycle

The present invention relates to a bicycle drive system and a bicycle front sprocket assembly.

Patent Document 1 discloses a bicycle drive system. The bicycle drive system has: a crank, a sprocket, and a sliding mechanism. The sliding mechanism connects the crank and the sprocket so as to be slidable in the axial direction of the rotation center axis of the sprocket. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] JP 2016-196236 A

[The problem to be solved by the invention]

Propose a bicycle drive system and a bicycle front sprocket assembly that can smoothly change the gear ratio in a wide range. [Technical means to solve the problem]

The drive system of the first aspect of the present invention includes a crank assembly, and a multiple rear sprocket assembly including a plurality of rear sprockets; the crank assembly includes a front sprocket, a crank arm, and the front The sprocket teeth of the sprocket can be displaced relative to the crank arm at least in the axial direction of the rotation center axis of the front sprocket; the plural rear sprocket includes: the smallest rear sprocket, the largest Rear sprockets, and at least 12 intermediate rear sprockets arranged in the axial direction between the smallest rear sprockets and the largest rear sprockets; the plurality of rear sprockets each have an axial direction with respect to the rotation center axis Outer face and axial inner face; the length between the outer face of the smallest rear sprocket in the axial direction and the inner face of the largest rear sprocket in the axial direction is defined as the axial length, and the axial length is Above 47.5mm.

With the first type of bicycle drive system, the sprocket gear shift mechanism allows multiple multiple rear sprocket assemblies to be multi-staged, prevents the chain from falling off, and has excellent drive efficiency. The gear ratio can be changed smoothly in a wide range.

According to the drive system of the second type according to the first type, the axial length is 48 mm or more.

With the second type of bicycle drive system, even when the dual rear sprocket assembly has a wide range of gear ratios, the chain can be prevented from falling off and the drive efficiency is excellent.

According to the drive system of the third type according to the second type, the axial length is 49 mm or more.

With the third type of bicycle drive system, even when the dual rear sprocket assembly has a wide range of gear ratios, the chain can be prevented from falling off and the drive efficiency is excellent.

According to the drive system of the fourth type according to any one of the first to third types, the gear ratio of the total number of teeth of the largest rear sprocket to the total number of teeth of the smallest rear sprocket is 3.4 or more.

With the fourth type of bicycle drive system, even when the dual rear sprocket assembly has a wide range of gear ratios, the chain can be prevented from falling off and the drive efficiency is excellent.

According to the drive system of the fifth type of any one of the first to fourth types, the sprocket density is defined as the total number of the plurality of rear sprockets divided by the axial length. The sprocket density It is 0.28 or more.

With the fifth type of bicycle drive system, even when the dual rear sprocket assembly has a wide range of gear ratios, the chain can be prevented from falling off and the drive efficiency is excellent.

According to the drive system of the sixth type of any one of the first to fifth types, the minimum rear sprocket has 12 or less total teeth, and the maximum rear sprocket has 42 or more total teeth.

With the sixth type of bicycle drive system, even when the dual rear sprocket assembly has a wide range of gear ratios, the chain can be prevented from falling off, and the drive efficiency is excellent.

According to the driving system of the seventh type according to any one of the first to sixth types, the total number of the plurality of rear sprockets is 14 or more.

With the seventh type of bicycle drive system, even when the dual rear sprocket assembly has a wide range of gear ratios, the chain can be prevented from falling off and the drive efficiency is excellent.

According to the driving system of the eighth form of any one of the first to seventh forms, the front sprocket is a single front sprocket.

With the eighth type of bicycle drive system, the front derailleur can be omitted from the bicycle drive system. Therefore, the weight of the bicycle drive system can be reduced, and the rider can concentrate on the rear shift operation.

According to the drive system of the ninth type of any one of the above-mentioned 1 to 8 types, the displacement width of the front sprocket with respect to the overall axis of the crank arm caused by the sprocket gear shifting mechanism is from 5 mm From the range of 30mm.

With the ninth type of bicycle drive system, when the bicycle drive system is installed in various frames, the inclination angle of the bicycle chain between the front sprocket and the rear sprocket relative to the center plane of the bicycle can be effectively reduced.

According to the drive system of the tenth form according to any one of the first to ninth forms, the drive system for the bicycle is mounted on the bicycle, and the front sprocket is in the front caused by the sprocket displacement mechanism. A state where the sprocket has a displacement width in the axial direction relative to the crank arm at the center point in the axial direction, and at least five of the intermediate rear sprockets are arranged in the axial center of the largest rear sprocket and the front sprocket in the axial direction Between the faces.

With the 10th type bicycle drive system, when the bicycle chain is engaged with the smallest rear sprocket of the compound rear sprocket assembly, the inclination angle of the bicycle chain relative to the center plane of the bicycle can be reduced.

The eleventh aspect of the bicycle front sprocket assembly of the present invention includes: a front sprocket and a sprocket tooth displacement mechanism; the front sprocket includes: a sprocket body and an outer periphery of the sprocket body The plurality of sprocket teeth; the sprocket body includes: a first connection with a first fastening axis, a second connection with a second fastening axis, and a third connection with a third fastening axis Part, and a fourth connecting part having a fourth fastening axis; the sprocket tooth displacement mechanism includes: a sprocket carrier and a base member; the sprocket carrier is coupled to the front sprocket; The base member is coupled to one of the crank arm and the crank shaft; the sprocket tooth displacement mechanism is assembled to the crank shaft and the crank arm in the assembled state of the bicycle front sprocket assembly, so that the front chain The plurality of sprocket teeth of the wheel can be displaced relative to the one of the crank arm and the crank shaft in at least the axial direction of the rotation center axis of the front sprocket; the sprocket carrier can be relative to the base member To move, the sprocket carrier includes: a fifth connecting portion with a fifth fastening axis, a sixth connecting portion with a sixth fastening axis, a seventh connecting portion with a seventh fastening axis, and a The eighth connecting portion of the eighth fastening axis; the second connecting portion, in the circumferential direction of the rotation center axis of the front sprocket, is separated from the first connecting portion and there is no other connecting portion therebetween; 3 The connecting portion is separated from the second connecting portion in the above-mentioned circumferential direction and there is no other connecting portion in between; the fourth connecting portion is separated from the first connecting portion and the third connecting portion in the above-mentioned circumferential direction, respectively And there is no other connecting part in between, and in the assembled state, the crank arm is positioned between the first connecting part and the fourth connecting part in the circumferential direction; the sixth connecting part is in the circumferential direction, and the first 5 The connecting part is separated without other connecting parts; the above-mentioned seventh connecting part is separated from the above-mentioned sixth connecting part in the above-mentioned circumferential direction and there is no other connecting part between; the above-mentioned 8th connecting part is in the above-mentioned circumferential direction , Are separated from the fifth and seventh connecting portions and there is no other connecting portion between them, and in the assembled state, the crank arm is positioned between the fifth and eighth connecting portions in the circumferential direction ; The first fastening axis of the first connecting portion and the fifth fastening axis of the fifth connecting portion are made to be aligned with each other on the first common axis so that the first fastening member passes through the first connecting portion And at least one of the fifth connecting portion; the second fastening axis of the second connecting portion and the sixth fastening axis of the sixth connecting portion are made so that the second common axis is aligned with each other so that the first 2 The fastening member is made by at least one of the second connection portion and the sixth connection portion; the third fastening axis of the third connection portion and the seventh fastening axis of the seventh connection portion. Align the third common axis with each other so that the third fastening member passes through at least one of the third connecting portion and the seventh connecting portion; the fourth fastening axis of the fourth connecting portion and the eighth connecting portion The above-mentioned 8th fastening axis is made on the 4th common axis Align the fourth fastening member to pass through at least one of the fourth connecting portion and the eighth connecting portion; the first connecting angle is used to prevent the other common axis from being located between the first common axis and the above in the circumferential direction. The second common axis is defined as the first reference line extending from the rotation center axis toward the first common axis in the circumferential direction and the first reference line extending from the rotation center axis toward the second common axis The angle between the second reference line; the second connecting angle is used to make the other common axis not located between the second common axis and the third common axis in the above circumferential direction, but is defined as in the above circumferential direction The angle between the second reference line and the third reference line extending from the rotation center axis toward the third common axis; the third connection angle is used to prevent the other common axis from being located in the circumferential direction of the first 3 The common axis and the fourth common axis are defined as the angle between the third reference line in the circumferential direction and the fourth reference line extending from the rotation center axis toward the fourth common axis ; The fourth connection angle is used to make the other common axis not located between the fourth common axis and the first common axis in the circumferential direction, but is defined as the fourth reference line and the first in the circumferential direction 1 The angle between the reference lines; at least one of the first connection angle, the second connection angle, the third connection angle, and the fourth connection angle, and the first connection angle, the second connection angle, The other of the third connection angle and the fourth connection angle is different.

With the 11th type of bicycle front sprocket assembly, the force applied to the crank during pedaling can be efficiently transmitted to the bicycle chain, which can improve driving efficiency.

According to the front sprocket assembly for a bicycle of the eleventh aspect and the twelfth aspect of the present invention, the first connection angle is smaller than the second connection angle and the fourth connection angle, respectively. The 12th type of bicycle front sprocket assembly can improve driving efficiency.

According to the eleventh or twelfth aspect of the thirteenth aspect of the bicycle front sprocket assembly of the present invention, the third connecting angle is smaller than the second connecting angle and the fourth connecting angle, respectively. The 13th type of bicycle front sprocket assembly can improve driving efficiency.

According to the front sprocket assembly for a bicycle of the fourteenth form according to any one of the 11th to 13th forms, the first connection angle is equal to the third connection angle. The 14th type of bicycle front sprocket assembly can improve driving efficiency.

According to the front sprocket assembly for a bicycle of the fifteenth form of any one of the 11th to 14th forms, the second connection angle is different from the fourth connection angle. The front sprocket assembly for bicycles of the 15th type described above can optimize the rigidity of the front sprocket.

According to the 15th aspect of the 16th aspect of the bicycle front sprocket assembly of the present invention, the second connection angle is smaller than the fourth connection angle. With the front sprocket assembly for bicycles of the 16th type described above, the rigidity of the front sprocket can be optimized.

According to a bicycle front sprocket assembly of a 17th aspect according to any one of the 11th to 16th aspects, the front sprocket has: a first axial direction surface, and a surface in the axial direction and the first axial direction The surface is the second axial direction surface on the opposite side; the second axial direction surface faces the center surface of the bicycle when the bicycle front sprocket assembly is mounted on the bicycle; the first to fourth common shafts When viewed from the first axial direction surface toward the second axial direction surface in the axial direction, the centers are arranged in the order of the first to fourth common axial centers in the counterclockwise direction from the crank arm in the circumferential direction. The 17th type bicycle front sprocket assembly can improve driving efficiency.

According to the bicycle front sprocket assembly of the 18th form according to any of the 11th to 17th forms, the base member is detachably connected to the crankshaft and the crank by means of spline engagement One of the above-mentioned arms of the arm. With the bicycle front sprocket assembly of the 18th type, the maintainability of the front sprocket can be improved.

The front sprocket assembly for a bicycle of the 19th aspect of the present invention includes: a front sprocket and a sprocket tooth displacement mechanism; the front sprocket includes: a sprocket body, and an outer periphery of the sprocket body The plurality of sprocket teeth; the sprocket tooth displacement mechanism includes: a sprocket carrier and a base member; the sprocket carrier is coupled to the front sprocket; the base member is coupled to the crank arm and One side of the crank shaft; the sprocket tooth shift mechanism, in the assembled state of the bicycle front sprocket assembly assembled on the crank shaft and the crank arm, so that the plurality of sprocket teeth of the front sprocket are at least The axis direction of the rotation center axis of the front sprocket can be displaced relative to the one of the crank arm and the crank shaft; the sprocket carrier can be moved relative to the base member; the sprocket tooth displacement mechanism , Including: a first sliding part with a first sliding center point, a second sliding part with a second sliding center point, a third sliding part with a third sliding center point, and a fourth sliding part with a fourth sliding center point The second sliding portion, in the circumferential direction of the rotation center axis of the front sprocket, is separated from the first sliding portion and there is no other connecting portion therebetween; the third sliding portion is in the circumferential direction with the The second sliding part is separated and there is no other connecting part between; The fourth sliding portion, in order to position the crank arm between the first sliding portion and the fourth sliding portion in the circumferential direction in the assembled state, respectively slides with the first sliding portion and the third sliding portion in the circumferential direction The first sliding angle is used to make other sliding center points not between the first sliding center point and the second sliding center point in the above-mentioned circumferential direction, but is defined as The angle between the first sliding reference line extending from the rotation center axis toward the first sliding center point in the circumferential direction and the second sliding reference line extending from the rotation center axis toward the second sliding center point; The sliding angle is used to make other sliding center points not located between the second sliding center point and the third sliding center point in the circumferential direction, but is defined as the second sliding reference line in the circumferential direction and from the rotation center The axis is the angle between the third sliding reference line extending toward the third sliding center point; the third sliding angle is used to make other sliding center points not located in the above-mentioned circumferential direction between the third sliding center point and the fourth sliding The center points are defined as the angle between the third sliding reference line in the circumferential direction and the fourth sliding reference line extending from the rotation center axis toward the fourth sliding center point; the fourth sliding angle is used So that other sliding center points are not located between the fourth sliding center point and the first sliding center point in the circumferential direction, but are defined as between the fourth sliding reference line and the first sliding reference line in the circumferential direction At least one of the first sliding angle, the second sliding angle, the third sliding angle, and the fourth sliding angle, and the first sliding angle, the second sliding angle, and the third sliding angle , And the other of the above-mentioned fourth sliding angle.

With the front sprocket assembly for bicycles of the 19th type, the rigidity of the sprocket gear shift mechanism can be improved.

According to the front sprocket assembly for a bicycle of the 19th aspect and the 20th aspect of the present invention, the first sliding angle is smaller than the second sliding angle and the fourth sliding angle, respectively.

With the front sprocket assembly for bicycles of the 20th type, the rigidity of the sprocket gear shift mechanism can be improved.

According to the 19th or 20th aspect of the 21st aspect of the bicycle front sprocket assembly of the present invention, the third sliding angle is smaller than the second sliding angle and the fourth sliding angle, respectively. The front sprocket assembly for bicycles of the 21st type can increase the rigidity of the sprocket gear shifting mechanism.

According to the bicycle front sprocket assembly of the 22nd form according to any one of the 19th to 21st forms, the first sliding angle is equal to the third sliding angle. With the 22nd type bicycle front sprocket assembly, the rigidity of the sprocket gear shift mechanism can be improved.

According to the bicycle front sprocket assembly of the 23rd type of any one of the 19th to 22nd types, the second sliding angle is different from the fourth sliding angle. With the 23rd type of bicycle front sprocket assembly, the rigidity of the sprocket gear shift mechanism can be improved.

According to the bicycle front sprocket assembly of the 24th form according to any of the 19th to 23rd forms, the second sliding angle is smaller than the fourth sliding angle. The 24th type of bicycle front sprocket assembly can increase the rigidity of the sprocket gear shift mechanism.

According to a bicycle front sprocket assembly of a 25th form according to any of the 19th to 24th forms, the front sprocket has: a first axial direction surface, and a direction between the axial direction and the first axial direction The surface is the second axial direction surface on the opposite side; the second axial direction surface, when the bicycle front sprocket assembly is mounted on the bicycle, opposes the center surface of the bicycle; the first to fourth sliding centers When the points are viewed from the first axial direction surface toward the second axial direction surface in the axial direction, the first to fourth sliding center points are arranged in the order from the crank arm in the counterclockwise direction in the circumferential direction. The 25th type of bicycle front sprocket assembly can increase the rigidity of the sprocket gear shift mechanism.

According to the bicycle front sprocket assembly of the 26th form according to any of the 19th to 25th forms, the base member is detachably connected to the crankshaft and the crank by spline engagement One of the above-mentioned arms of the arm. The front sprocket assembly for bicycles of the 26th type can improve the maintainability of the front sprocket.

A bicycle front sprocket assembly according to a 27th aspect of the present invention includes a front sprocket and a sprocket tooth displacement mechanism; the front sprocket includes: a sprocket body and an outer periphery of the sprocket body The sprocket body includes at least one connecting portion; the sprocket tooth displacement mechanism includes: a sprocket carrier and a base member; the sprocket carrier is coupled to the front sprocket; The base member is coupled to one of the crank arm and the crank shaft; the sprocket tooth displacement mechanism is assembled to the crank shaft and the crank arm in the assembled state of the bicycle front sprocket assembly, so that the front The plurality of sprocket teeth of the sprocket can be displaced relative to the one of the crank arm and the crank shaft in at least the axial direction of the rotation center axis of the front sprocket; the sprocket carrier can be relative to the base The component moves; the sprocket carrier includes at least one additional connecting portion; the at least one connecting portion and the at least one additional connecting portion are combined with each other by at least one fastening member; the sprocket tooth displacement mechanism includes at least one sliding Section; The total number of the at least one fastening member is equal to the total number of the at least one sliding portion.

With the 27th type of bicycle front sprocket assembly, the number of sliding parts between the sprocket carrier and the sprocket is equal to the number of sliding parts between the base member and the sprocket carrier, so It can efficiently transmit the driving force from the crankshaft to the sprocket.

According to the 27th aspect of the 28th aspect of the bicycle front sprocket assembly of the present invention, the base member is detachably connected to one of the crankshaft and the crank arm by spline engagement . The front sprocket assembly for bicycles of the 28th type described above can improve the maintainability of the front sprocket.

According to the 27th or 28th aspect of the 29th aspect of the bicycle front sprocket assembly of the present invention, the at least one connecting portion includes a plurality of connecting portions, the at least one additional connecting portion includes a plurality of connecting portions, and the at least one The fastening member includes a plurality of fastening members, the at least one sliding portion includes a plurality of sliding portions, and the total number of the plurality of fastening members is equal to the total number of the plurality of sliding portions.

With the 29th type bicycle front sprocket assembly, the driving force can be efficiently transmitted from the crankshaft to the sprocket.

According to the bicycle front sprocket assembly of the 30th form of any one of the 27th to the 29th forms of the present invention, the at least one sliding portion is arranged in the vicinity of the at least one fastening member in the assembled state.

With the 30-type bicycle front sprocket assembly, the driving force can be efficiently transmitted from the crankshaft to the sprocket.

According to the front sprocket assembly for a bicycle of the 31st form of any one of the 27th to 30th forms of the present invention, the at least one sliding portion is arranged to drive rotation relative to the at least one fastening member in the assembled state The upstream side of the direction.

With the 31st type of bicycle front sprocket assembly, the driving force can be efficiently transmitted from the crankshaft to the sprocket.

The 32nd aspect of the bicycle front sprocket assembly of the present invention is provided with: a front sprocket, a sprocket tooth displacement mechanism; the front sprocket includes: a sprocket body, and a rotation center shaft of the front sprocket The plurality of sprocket teeth arranged on the outer circumference of the sprocket body in the circumferential direction of the center; the plurality of sprocket teeth have: at least one first having a first largest chain engagement axis width relative to the rotation center axis 1 tooth, and at least one second tooth having the second largest chain engagement axis width relative to the rotation center axis; in the axis direction of the rotation center axis, the first largest chain engagement axis width is greater than The second maximum chain engagement axis direction width; the sprocket tooth displacement mechanism includes: a sprocket carrier and a base member; the sprocket carrier is coupled to the front sprocket; the base member, by The sprocket gear shift mechanism is coupled to one of the crank arm and the crank shaft by groove engagement; in the assembled state of the bicycle front sprocket assembly assembled on the crank shaft and the crank arm, the front chain The plurality of sprocket teeth of the wheel can be displaced relative to the one of the crank arm and the crank shaft in at least the axial direction of the rotation center axis of the front sprocket; the sprocket carrier can be relative to the base member mobile.

With the 32-type bicycle front sprocket assembly, the assembly including the sprocket tooth displacement mechanism can improve driving efficiency and increase the chain retention of the front sprocket.

According to the 32nd aspect of the 33rd aspect of the bicycle front sprocket assembly of the present invention, the base member is detachably connected to the one of the crankshaft and the crank arm by a spline engagement method .

With the 33rd type of bicycle front sprocket assembly, the maintainability of the front sprocket can be improved.

The bicycle front sprocket assembly according to the 32nd or 33rd aspect of the 34th aspect of the present invention further includes a locking member for preventing the base member from being relative to the crank arm in the assembled state. And the said one of the said crank shaft is displaced and engages with the said one of the said crank arm and the said crank shaft.

With the 34th type bicycle front sprocket assembly, the front sprocket can be easily detached.

According to the bicycle front sprocket assembly of the 35th form of any one of the 32nd to the 34th forms of the present invention, the first maximum chain engagement axial width is greater than: by the bicycle chain in the axial direction A pair of inner link pieces defined in the inner link axis direction interval, and is smaller than: by the above-mentioned axial direction bicycle chain defined between a pair of outer link pieces; 2 The maximum chain engagement axis width is smaller than the above-mentioned inner link axis interval.

The 35-type bicycle front sprocket assembly can improve the chain retention of the front sprocket.

According to the 36th version of the bicycle front sprocket assembly of any one of the 32nd to 35th versions of the present invention, the first radial length is defined as the at least one of the above-mentioned at least one in the radial direction of the above-mentioned rotation center axis The length between the first radial outermost tooth end of the first tooth and the rotation center axis; the second radial length is defined as the at least one second tooth in the radial direction relative to the rotation center axis The length between the second radial outermost tooth end and the rotation center axis; the first radial length is greater than the second radial length.

According to the 36-type bicycle front sprocket assembly, the first tooth having the first radial length is engaged at an earlier time than the second tooth during the rotation of the front sprocket. In this way, the bicycle chain is stably engaged, and the holding force of the bicycle chain of the front sprocket can be improved.

According to the 35th aspect of the 37th aspect of the bicycle front sprocket assembly of the present invention, the first maximum chain engagement axis width of the at least one first tooth is 75% of the outer link axis direction. %the above.

The 37-type bicycle front sprocket assembly can improve the chain retention of the front sprocket.

According to the bicycle front sprocket assembly of any one of the 32nd to the 37th forms of the present invention, the at least one first tooth has: a distance from the at least one first tooth in the axial direction The first axis direction tooth end center line offset from the first axis direction tooth bottom center surface.

With the 38th type bicycle front sprocket assembly, when the bicycle chain is close to the offset side of the tooth end of the first tooth relative to the center surface of the bicycle, the holding force of the bicycle chain can be improved.

According to the front sprocket assembly for a bicycle of the 39th form of any one of the 32nd to the 37th forms of the present invention, the at least one second tooth has: a distance from the at least one second tooth in the axial direction The second axis direction tooth end center line offset from the second axis direction tooth bottom center surface.

With the 39-type bicycle front sprocket assembly, relative to the center surface of the bicycle, when the bicycle chain is close to the offset side of the second tooth, the holding force of the bicycle chain can be improved.

According to the bicycle front sprocket assembly of the 40th version of any one of the 32nd to the 39th versions of the present invention, the at least one first tooth is in the circumferential direction relative to the tooth bottom center line in the first circumferential direction asymmetric. With the front sprocket assembly for bicycles of the 40th type, the chain retention force of the front sprocket can be improved.

According to the front sprocket assembly for a bicycle of the 41st form of any one of the 32nd to the 40th forms of the present invention, the at least one second tooth is in the circumferential direction relative to the tooth bottom center line in the second circumferential direction asymmetric. With the 41st type of bicycle front sprocket assembly, the chain retention force of the front sprocket can be improved.

According to the front sprocket assembly for a bicycle of any one of the 32nd to 41st forms of the present invention, the at least one first tooth is opposite to the tooth bottom center surface in the first axial direction in the axial direction It is asymmetric. The 42nd type bicycle front sprocket assembly can improve the chain retention of the front sprocket.

According to the front sprocket assembly for a bicycle of any one of the 32nd to 42nd forms of the present invention, the at least one second tooth is opposite to the tooth bottom center surface in the second axial direction in the axial direction It is asymmetric. With the 43rd type of bicycle front sprocket assembly, the chain retention force of the front sprocket can be improved.

According to the bicycle front sprocket assembly of the 44th form of any one of the 32nd to the 43rd forms of the present invention, the at least one first tooth includes a plurality of first teeth, and the at least one second tooth, It includes plural second teeth, and the plural first teeth and the plural second teeth are alternately arranged in the circumferential direction. The 44-type bicycle front sprocket assembly can improve the chain retention of the front sprocket. [Invention Effect]

With the bicycle drive system of the present invention, the sprocket gear shifting mechanism can multi-stage multiple multiple rear sprocket assemblies, can prevent the chain from falling off, and has excellent drive efficiency. The gear ratio can be changed smoothly in a wide range.

<First Embodiment>

The driving system 12 for a bicycle will be described with reference to Fig. 1. Fig. 1 is a view of a human-powered vehicle to which a bicycle drive system 12 is applied, viewed from above, and only the bicycle drive system 12 is shown. Human-powered vehicles represent vehicles that use human power at least partially, and include vehicles that assist human power in an electrically powered manner. Vehicles that only use power other than human power are not included in human-powered vehicles. Vehicles powered only by internal combustion engines are not included in human-powered vehicles. The usual human-powered vehicles are scheduled to be small and light vehicles, and are scheduled to be vehicles that do not require a driving license on the highway. The illustrated human-powered vehicle includes bicycle A. Bicycle A includes mountain bikes and road bikes. Specifically, the human-powered vehicle is bicycle A. The bicycle A includes: a frame for supporting two wheels, a crankshaft 2 rotatably supported by the frame 1, a pair of crank arms 4 respectively provided at both ends of the crankshaft 2, a front chain wheel 6, and a rear chain Wheel 8, bicycle chain 10. The bicycle A includes a bicycle drive system 12.

The bicycle drive system 12 will be described with reference to FIGS. 1 to 4. As shown in FIG. 1, the bicycle drive system 12 includes a crank assembly 14 and a multiple rear sprocket assembly 16 including a plurality of rear sprockets 8.

The crank assembly 14 includes: a front sprocket 6, a crank arm 4, and the sprocket teeth 18 of the front sprocket 6 can be displaced relative to the crank arm 4 in at least the axis direction DA of the rotation center axis CA of the front sprocket 6 The sprocket gear shift mechanism 20.

The plural rear sprockets 8 include: the smallest rear sprocket 22, the largest rear sprocket 24, and at least 12 intermediate rear sprocket 26 arranged between the smallest rear sprocket 22 and the largest rear sprocket 24 in the axial direction DA .

The crank assembly 14 is attached to the frame 1 of the bicycle A. The multiple rear sprocket assembly 16 is mounted on the hub of the rear wheel of the bicycle A. The bicycle chain 10 is hung around the front sprocket 6 and the compound rear sprocket assembly 16.

In an example of the sprocket gear shift mechanism 20 of the present invention shown in FIG. 2, by moving the front sprocket 6 in the axial direction DA of the rotation center axis CA of the front sprocket 6, the sprocket 18 The front sprocket 6 is displaced in parallel with the axis direction DA of the rotation center axis CA. In FIG. 2, the first position P1 of the front sprocket 6 when the front sprocket 6 is closest to the center surface CS side of the bicycle A by the sprocket tooth shift mechanism 20 is shown by a solid line. In Fig. 2, the second position P2 of the front sprocket 6 when the front sprocket 6 is spaced from the outermost side of the center plane CS of the bicycle A by the sprocket tooth shift mechanism 20 is shown with a two-dot chain line. The distance between the first position P1 and the second position P2 is defined as the displacement width RD of the front sprocket 6 in the general axis direction. The intermediate point between the first position P1 and the second position P2 in the axial direction DA is defined as the axial center point PCR.

In another example of the sprocket gear shift mechanism 20 of the present invention shown in FIG. 3, by causing the front sprocket 6 to swing in the swing direction DZ centered on the axis CZ along the vertical direction of the human-powered vehicle, Then, the sprocket teeth 18 are displaced in the axial direction DA of the rotation center axis CA of the front sprocket 6.

With reference to Fig. 4, the description will be made regarding the compound rear sprocket assembly 16. FIG. 4 shows a schematic diagram of the compound rear sprocket assembly 16 and shows the arrangement relationship between the compound rear sprocket assembly 16 and the front sprocket 6 in the axial direction DA.

Each of the plural rear sprockets 8 has an axial outer surface portion 30 and an axial inner surface portion 32 with respect to the rotation center axis CA. The axial length LA defined as the length between the axial outer surface portion 30 of the smallest rear sprocket 22 and the axial inner surface 32 of the largest rear sprocket 24 in the axial direction DA is preferably 47.5 mm or more.

The axial length LA is preferably 48 mm or more. In addition, the axial length LA is preferably 49 mm or more.

The gear ratio of the total number of teeth of the largest rear sprocket 24 to the total number of teeth of the smallest rear sprocket 22 is preferably 3.4 or more.

The sprocket density is defined as the value obtained by dividing the total number of plural rear sprockets 8 by the axial length LA. In this embodiment, the sprocket density is preferably 0.28 or more.

The minimum rear sprocket 22 has a total number of teeth of 12 or less, and the maximum rear sprocket 24 has a total number of teeth of 42 or more. As an example, the minimum total number of teeth of the rear sprocket 22 is any of 9, 10, 11, or 12. The total number of teeth of the largest rear sprocket 24 is any of 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52. The total number of plural rear sprockets 8 is preferably 14 or more.

Two examples are given below in which the total number of teeth of the front sprocket 6 and the total number of teeth of each rear sprocket 8 of the compound rear sprocket assembly 16 are combined. The first example is as follows. The total number of teeth of the front sprocket 6 is 58. The total number of teeth of each rear sprocket 8 of the multiple rear sprocket assembly 16 is 12, 13, 14, 15, 17, 19, 21, 23, 25, 28, 31. , 34, 38, 42. The total number of rear sprockets 8 of the multiple rear sprocket assembly 16 is 14. The gear ratio is 3.5.

The second example is as follows. The total number of teeth of the front sprocket 6 is 43. The total number of teeth of each rear sprocket 8 of the multiple rear sprocket assembly 16 is 10, 11, 13, 15, 17, 19, 21, 23, 26, 29, 33 respectively , 37, 42, 47. The total number of rear sprockets 8 of the multiple rear sprocket assembly 16 is 14. The gear ratio is 4.7.

The front sprocket 6 is preferably a single front sprocket. The displacement width RD of the front sprocket 6 relative to the crank arm 4 in the overall axis direction caused by the sprocket tooth displacement mechanism 20 is in the range of 5 mm to 30 mm. The displacement width RD in the overall axis direction is preferably 7 mm to 10 mm.

As shown in Figure 1, the bicycle drive system 12 is mounted on the bicycle A, and the front sprocket 6 is displaced by the sprocket gear shift mechanism 20 in the direction of the total axis of the crank arm 4 In a state where RD is located at the axial center point PCR, it is preferable that at least five intermediate rear sprockets 26 are arranged between the largest rear sprocket 24 and the axial center plane PCS of the front sprocket 6 in the axial direction DA. It is more preferable to arrange at least six intermediate rear sprocket 26 between the largest rear sprocket 24 and the axial center plane PCS of the front sprocket 6 in the axial direction DA. In the embodiment shown in FIG. 4, six intermediate rear sprockets 26 are arranged between the largest rear sprocket 24 and the axial center plane PCS of the front sprocket 6 in the axial direction DA.

In the bicycle drive system 12 of the present embodiment, it is preferable to apply at least one structure from the second embodiment to the fifth embodiment described later.

The function of the sprocket gear shift mechanism 20 will be described. The sprocket carrier 42 can be displaced relative to the crank arm 4 in the axial direction DA of the rotation center axis CA of the front sprocket 6. When the bicycle A is traveling, when the multiple rear sprocket assembly 16 performs a shift operation, the force in the axial direction DA of the rotation center axis CA acts on the front sprocket 6 via the bicycle chain 10. Then, the sprocket carrier 42 moves in the same direction as the moving direction of the chain along with the bicycle chain 10. Thereby, the inclination of the bicycle chain 10 with respect to the center plane CS of the bicycle A is reduced, driving efficiency can be improved, and the chain can be prevented from falling off. With this effect, the total number of rear sprockets 8 of the multiple rear sprocket assembly 16 can be increased.

The bicycle drive system 12 includes a sprocket gear shift mechanism 20. And the multiple rear sprocket assembly 16 includes at least 14 rear sprocket 8. The bicycle drive system 12 includes a sprocket gear shift mechanism 20 and at least 14 rear sprockets 8, which can prevent the chain from falling off and can smoothly change the gear ratio in a wide range.

<Second Embodiment> The bicycle front sprocket assembly 34 including the sprocket gear shift mechanism 20 will be described.

The bicycle front sprocket assembly 34 includes a front sprocket 6 and a sprocket tooth shift mechanism 20.

The front sprocket 6 includes a sprocket body 36 and a plurality of sprocket teeth 18 arranged on the outer periphery of the sprocket body 36. The front sprocket 6 has a first axial direction surface 38 and a second axial direction surface 40 on the opposite side of the first axial direction surface 38 in the axial direction DA (refer to FIG. 10). The second axial direction surface 40 faces the center surface CS of the bicycle A in a state where the bicycle front sprocket assembly 34 is attached to the bicycle A.

The sprocket gear shift mechanism 20 includes a sprocket carrier 42 coupled to the front sprocket 6 and a base member 44 coupled to one of the crank arm 4 and the crank shaft 2.

The sprocket shift mechanism 20, in the assembled state of the bicycle front sprocket assembly 34 assembled on the crankshaft 2 and the crank arm 4, allows the plural sprocket teeth 18 of the front sprocket 6 to be at least on the front sprocket 6 The axis direction DA of the rotation center axis CA can be displaced relative to the above-mentioned one of the crank arm 4 and the crank shaft 2, and the sprocket carrier 42 can move relative to the base member 44.

An example of the sprocket gear displacement mechanism 20 will be described with reference to FIGS. 5 to 12. Fig. 5 is a perspective view of an assembly including the sprocket gear shift mechanism 20, the crank shaft 2, the crank arm 4, and the front sprocket 6. Figure 6 is a side view of the assembly. Fig. 7 is an exploded perspective view of the assembly. FIG. 8 is an exploded perspective view of the sprocket gear shift mechanism 20. FIG. FIG. 9 is an exploded perspective view of the sliding portion 52 and the holding member 54. Fig. 10 is a cross-sectional view taken along line X-X in Fig. 6. Figure 11 is a partial enlarged view of Figure 10.

The base member 44 is attached to one of the crank shaft 2 and the crank arm 4. The base member 44 may be detachably connected to one of the crank shaft 2 and the crank arm 4 by spline engagement. In this case, it is preferable that the sprocket displacement mechanism 20 further includes a lock member 46. The lock member 46 is used to restrain the base member 44 from shifting with respect to one of the crank arm 4 and the crank shaft 2 in the assembled state, and engage with one of the crank arm 4 and the crank shaft 2.

In this embodiment, the base member 44 is detachably connected to the crank arm 4 by spline engagement. As shown in FIGS. 10 and 11, the crank arm 4 has an insertion hole 4a through which the crank shaft 2 is inserted, and a cylindrical protrusion 4b provided to surround one end of the insertion hole 4a. The protruding portion 4b of the crank arm 4 is formed with a spline 4d parallel to the axial direction DA along the rotation center axis CA of the front sprocket 6 in the assembled state.

As shown in FIG. 11, the base member 44 has a main body portion 48 surrounding the base end portion 4 c of the crank arm 4, and an attachment portion 50 provided on the main body portion 48 and attached to the protrusion 4 b of the crank arm 4. As shown in FIG. 8, the main body portion 48 of the base member 44 is provided with at least one first sliding surface 51. The mounting portion 50 of the base member 44 is formed with a groove for engaging with the spline 4d of the crank arm 4.

As shown in FIG. 10, the base member 44 is fixed to the crank arm 4 by the locking member 46. The lock member 46 is used to suppress the displacement of the base member 44 with respect to the crank arm 4 in the assembled state, and to engage with one of the crank arm 4 and the crank shaft 2. The locking member 46 may be composed of one part, or may be composed of a plurality of parts.

In this embodiment, the sliding portion 52 includes a first sliding surface 51, a second sliding surface 61, and a sliding body 53. The first sliding surface 51 of the base member 44 is used to support the sliding body 53. In this embodiment, the sliding body 53 is a rolling body made of steel balls, for example. The sliding body 53 may be a needle-shaped rolling body. As shown in FIG. 9, the sliding body 53 is held by the holding member 54. The first sliding surface 51 of the base member 44 slides with the sliding body 53 so that the base member 44 is movable relative to the sprocket carrier 42 in the axial direction DA of the rotation center axis CA of the front sprocket 6. The holding member 54 has four holding parts 56 that rotatably hold the sliding body 53. The holding portion 56 has a first surface portion 56 a facing the first sliding surface 51 of the base member 44 and a second surface portion 56 b facing the second sliding surface 61 provided on the sprocket carrier 42. Holes 56c for accommodating the slider 53 are provided in the first surface portion 56a and the second surface portion 56b. The sliding portion 52 may have a structure in which the sliding body 53 is omitted and the first sliding surface 51 and the second sliding surface 61 directly slide.

As shown in FIG. 5, the front sprocket 6 is attached to the sprocket carrier 42. The sprocket carrier 42 has a main body portion 58 surrounding the base member 44 and a connection portion 60 provided on the main body portion 58 and connected to the front sprocket 6. At least one second sliding surface 61 is provided on the main body portion 58 of the sprocket carrier 42. The main body 58 has a through hole 58 a through which the end of the crank shaft 2 is inserted. The second sliding surface 61 is provided on the inner peripheral surface 58 b of the main body 58. The main body portion 58 is provided with a concave portion 58c from the outer surface to the inner surface in the axial direction DA. The recess 58c is used to configure a part of the crank arm 4. The second sliding surface 61 slides with the sliding body 53. The second sliding surface 61 slides with the sliding body 53 with respect to the base member 44 and is movable in the axial direction DA of the rotation center axis CA of the front sprocket 6. The driving force of the crankshaft 2 is transmitted to the sprocket carrier 42 via the sliding body 53.

As shown in FIGS. 5 and 6, in this embodiment, the sprocket carrier 42 is fastened to the front sprocket 6 by the fastening member 64. A cover attaching member 66 for attaching a dust cover 68 to the sprocket carrier 42 is attached. After the cover mounting member 66 is mounted on the radially outer side of the dust cover 68, when the fastening member 64 is fastened to the connecting portions 60 and 70, the head of the fastening member 64 and the sprocket carrier 42 sandwich the cover The mounting member 66 fixes the cover mounting member 66.

The connection between the sprocket carrier 42 and the front sprocket 6 can also be configured as follows. One of the sprocket carrier 42 and the front sprocket 6 is provided with a convex portion for engaging with a concave portion or a through hole provided on the other. The sprocket carrier 42 and the front sprocket 6 are connected by the caulking of the convex portion.

As shown in FIGS. 5 and 6, the sprocket gear shift mechanism 20 is further preferably covered by a dust cover 68. The dust cover 68 includes at least a first cover portion 68a and a second cover portion 68b. The first cover portion 68 a is arranged on the first axial surface 38 side of the front sprocket 6 in the axial direction DA of the rotation center axis CA of the front sprocket 6. The first cover portion 68 a covers the gap between the sprocket carrier 42 and the base member 44 and the sliding portion 52. The second cover portion 68 b is arranged on the second axial direction surface 40 side of the front sprocket 6 in the axial direction DA of the rotation center axis CA of the front sprocket 6. The second cover portion 68b covers the gap between the sprocket carrier 42 and the base member 44 and the sliding portion 52.

With reference to Figures 12 to 14, the fastening structure of the front sprocket 6 and the sprocket carrier 42 will be described. Fig. 12 is a side view of the front sprocket 6. FIG. 13 is a side view of the sprocket 42. FIG. 14 is a side view of the assembly of the front sprocket 6 and the sprocket carrier 42.

The sprocket main body 36 includes: a first connection portion 70A having a first fastening axis AF1, a second connection portion 70B having a second fastening axis AF2, and a third connection portion 70C having a third fastening axis AF3 , And a fourth connecting portion 70D having a fourth fastening axis AF4.

The sprocket main body 42 includes: a fifth connection portion 60E having a fifth fastening axis AF5, a sixth connection portion 60F having a sixth fastening axis AF6, and a seventh connection portion 60G having a seventh fastening axis AF7 , And an eighth connecting portion 60H having an eighth fastening axis AF8.

The second connecting portion 70B is separated from the first connecting portion 70A in the circumferential direction DC of the rotation center axis CA of the front sprocket 6 without other connecting portions 70C, 70D therebetween.

The third connecting portion 70C is separated from the second connecting portion 70B in the circumferential direction DC and there are no other connecting portions 70A, 70D therebetween. The fourth connecting portion 70D is separated from the first connecting portion 70A and the third connecting portion 70C in the circumferential direction DC, and there is no other connecting portion 70B in between, and the crank arm 4 is positioned at the first in the circumferential direction DC in the assembled state. Between the connecting portion 70A and the fourth connecting portion 70D.

The sixth connecting portion 60F is separated from the fifth connecting portion 60E in the circumferential direction DC and there are no other connecting portions 60G and 60H therebetween. The seventh connecting portion 60G is separated from the sixth connecting portion 60F in the circumferential direction DC and there are no other connecting portions 60E, 60H therebetween.

The eighth connecting portion 60H is separated from the fifth connecting portion 60E and the seventh connecting portion 60G in the circumferential direction DC, and there is no other connecting portion 60F in between, and the crank arm 4 is positioned at the fifth in the circumferential direction DC in the assembled state. Between the connecting portion 60E and the eighth connecting portion 60H.

The first fastening axis AF1 of the first connecting portion 70A and the fifth fastening axis AF5 of the fifth connecting portion 60E are made to be aligned with each other with respect to the first common axis AC1, so that the first fastening member 64A passes through the first At least one of the connecting portion 70A and the fifth connecting portion 60E.

The second fastening axis AF2 of the second connecting portion 70B and the sixth fastening axis AF6 of the sixth connecting portion 60F are formed to be aligned with each other with respect to the second common axis AC2, so that the second fastening member 64B passes through the second At least one of the connecting portion 70B and the sixth connecting portion 60F.

The third fastening axis AF3 of the third connecting portion 70C and the seventh fastening axis AF7 of the seventh connecting portion 60G are made to be aligned with each other with respect to the third common axis AC3, so that the third fastening member 64C passes through the third At least one of the connecting portion 70C and the seventh connecting portion 60G.

The fourth fastening axis AF4 of the fourth connecting portion 70D and the eighth fastening axis AF8 of the eighth connecting portion 60H are made to be aligned with each other with respect to the fourth common axis AC4, so that the fourth fastening member 64D passes through the fourth At least one of the connecting portion 70D and the eighth connecting portion 60H.

The first connection angle AG1, in order to prevent the other common axis AC3, AC4 from being located between the first common axis AC1 and the second common axis AC2 in the circumferential direction DC, is defined as the circumferential direction DC from the rotation center axis CA The angle between the first reference line LR1 extending from the first common axis AC1 and the second reference line LR2 extending from the rotation center axis CA toward the second common axis AC2.

The second connection angle AG2, in order to prevent the other common axis AC1 and AC4 from being located between the second common axis AC2 and the third common axis AC3 in the circumferential direction DC, is defined as the second reference line LR2 in the circumferential direction DC and from The angle between the rotation center axis CA and the third reference line LR3 extending toward the third common axis AC3.

The third connection angle AG3, in order to prevent the other common axis AC1 and AC2 from being located between the third common axis AC3 and the fourth common axis AC4 in the circumferential direction DC, is defined as the third reference line LR3 in the circumferential direction DC and from The angle between the rotation center axis CA and the fourth reference line LR4 extending toward the fourth common axis AC4.

The fourth connection angle AG4 is defined as the fourth reference line LR4 and the fourth reference line LR4 in the circumferential direction DC so that the other common axis AC2 and AC3 are not located between the fourth common axis AC4 and the first common axis AC1 in the circumferential direction DC 1 The angle between the reference line LR1.

At least one of the first connection angle AG1, the second connection angle AG2, the third connection angle AG3, and the fourth connection angle AG4 is connected to the first connection angle AG1, the second connection angle AG2, the third connection angle AG3, and the The other of the 4 connection angle AG4 is different.

The first connection angle AG1 is preferably smaller than the second connection angle AG2 and the fourth connection angle AG4, respectively. The third connection angle AG3 is preferably smaller than the second connection angle AG2 and the fourth connection angle AG4, respectively.

Preferably, the first connection angle AG1 and the third connection angle AG3 are equal. Preferably, the second connection angle AG2 and the fourth connection angle AG4 are different. Preferably, the second connection angle AG2 is smaller than the fourth connection angle AG4.

When the axial direction DA is viewed from the first axial direction surface 38 toward the second axial direction surface 40 (refer to FIG. 10), the first common axis AC1 to the fourth common axis AC4 are arranged from the crank in the circumferential direction DC The CCW from the arm 4 in the counterclockwise direction preferably starts from the first common axis AC1 to the fourth common axis AC4.

FIG. 15 is a side view of the assembly of the front sprocket 6 and the sprocket carrier 42 with the base member 44 and the crank arm 4. As shown in FIG. 13, in an example, the first connecting portion 70A to the fourth connecting portion 70D of the front sprocket 6 are arranged outside the sliding portion 52 in the radial direction of the rotation center axis CA of the front sprocket 6 .

With reference to Fig. 16, the operation of the sprocket gear shift mechanism 20 of this embodiment will be described. The sprocket carrier 42 is displaceable with respect to the base member 44 attached to the crank arm 4 in the axial direction DA of the rotation center axis CA of the front sprocket 6. When the bicycle A is traveling, when the multiple rear sprocket assembly 16 performs a shift operation, the force in the axial direction DA of the rotation center axis CA acts on the front sprocket 6 via the bicycle chain 10. Then, the sprocket carrier 42 moves in the same direction as the moving direction of the chain along with the bicycle chain 10.

The function of the bicycle front sprocket assembly 34 will be described. The driving force of one of the crank arm 4 and the crank shaft 2 is transmitted from the base member 44 to the front sprocket 6 via the sprocket carrier 42. The sprocket carrier 42 is connected to the front sprocket 6 at four locations. As described above, at least one of the first connection angle AG1, the second connection angle AG2, the third connection angle AG3, and the fourth connection angle AG4 is connected to the first connection angle AG1, the second connection angle AG2, and the third connection angle AG3 , And the other of the fourth connection angle AG4. When the right crank arm 4 is stepped on and driven, the tension of the bicycle chain 10 is strongly applied to the sprocket teeth located between the first reference line LR1 and the second reference line LR2 used to define the first connection angle AG1. By reducing the first connection angle AG1, the rigidity of the bicycle front sprocket assembly 34 when the right crank arm 4 is stepped on and driven can be improved. When the left crank arm 4 is stepped on and driven, the tension of the bicycle chain 10 is strongly applied to the sprocket teeth located between the third reference line LR3 and the fourth reference line LR4 used to define the third connection angle AG3. By reducing the third connection angle AG3, the rigidity of the bicycle front sprocket assembly 34 when the left crank arm 4 is stepped on and driven can be improved. Therefore, by reducing at least one of the first connection angle AG1 and the third connection angle AG3, and it is more preferable to reduce both the first connection angle AG1 and the third connection angle AG3, the driving efficiency can be improved.

<The third embodiment> With reference to Fig. 15, a bicycle front sprocket assembly 34 including an example of the sprocket gear shift mechanism 20 will be described. The same reference numerals as those in the second embodiment are assigned to the structures common to the second embodiment, and overlapping descriptions are omitted.

The bicycle front sprocket assembly 34 includes a front sprocket 6 and a sprocket tooth shift mechanism 20.

The front sprocket 6 includes a sprocket body 36 and a plurality of sprocket teeth 18 arranged on the outer periphery of the sprocket body 36. The front sprocket 6 has a first axial direction surface 38 and a second axial direction surface 40 opposite to the first axial direction surface 38 in the axial direction DA. The second axial direction surface 40 faces the center surface CS of the bicycle A in a state where the bicycle front sprocket assembly 34 is attached to the bicycle A.

The sprocket gear shift mechanism 20 includes a sprocket carrier 42 coupled to the front sprocket 6 and a base member 44 coupled to one of the crank arm 4 and the crank shaft 2.

The sprocket shift mechanism 20, in the assembled state of the bicycle front sprocket assembly 34 assembled on the crankshaft 2 and the crank arm 4, allows the plural sprocket teeth 18 of the front sprocket 6 to be at least on the front sprocket 6 The axis direction DA of the rotation center axis CA can be displaced relative to the above-mentioned one of the crank arm 4 and the crank shaft 2, and the sprocket carrier 42 can move relative to the base member 44.

The structure of the sprocket shift mechanism 20 is the same as that of the sprocket shift mechanism 20 of the second embodiment. The fastening structure of the front sprocket 6 and the base member 44 is not limited. The fastening structure of the front sprocket 6 and the base member 44 is preferably the same as the fastening structure exemplified in the second embodiment.

The base member 44 is attached to one of the crank shaft 2 and the crank arm 4. The base member 44 may be detachably connected to one of the crank shaft 2 and the crank arm 4 by spline engagement.

The sprocket displacement mechanism 20 includes a first sliding portion 52A having a first sliding center point PS1, a second sliding portion 52B having a second sliding center point PS2, and a third sliding portion 52C having a third sliding center point PS3 , And a fourth sliding portion 52D having a fourth sliding center point PS4.

The second sliding portion 52B is separated from the first sliding portion 52A in the circumferential direction DC of the rotation center axis CA of the front sprocket 6 and there is no other sliding portion 52 therebetween. The third sliding portion 52C is opposite to the first sliding portion 52 in the circumferential direction DC. The two sliding parts 52B are separated and there is no other sliding part 52 in between.

The fourth connecting portion 52D is separated from the first sliding portion 52A and the third sliding portion 52C in the circumferential direction DC, and there is no other sliding portion 52 therebetween. In the assembled state, the crank arm 4 is positioned at the first in the circumferential direction DC. Between the sliding portion 52A and the fourth sliding portion 52D.

The first sliding angle AGS1, in order to prevent the other sliding center points PS3 and PS4 from being located between the first sliding center point PS1 and the second sliding center point PS2 in the circumferential direction DC, is defined as the circumferential direction DC from the rotation center axis CA The angle between the first sliding reference line PRS1 extending from the first sliding center point PS1 and the second sliding reference line PRS2 extending from the rotation center axis CA toward the second sliding center point PS2.

The second sliding angle AGS2 is defined as the second sliding reference line PRS2 in the circumferential direction DC so that the other sliding center points PS1 and PS4 are not located between the second sliding center point PS2 and the third sliding center point PS3 in the circumferential direction DC The angle between the third sliding reference lines PRS3 extending from the rotation center axis CA toward the third sliding center point PS3.

The third sliding angle AGS3 is defined as the third sliding reference line PRS3 in the circumferential direction DC so that the other sliding center points PS1 and PS2 are not located between the third sliding center point PS3 and the fourth sliding center point PS4 in the circumferential direction DC The angle between the fourth sliding reference lines PRS4 extending from the rotation center axis CA toward the fourth sliding center point PS4.

The fourth sliding angle AGS4 is defined as the fourth sliding reference line PRS4 in the circumferential direction DC so that the other sliding center points PS2 and PS3 are not located between the fourth sliding center point PS4 and the first sliding center point PS1 in the circumferential direction DC The angle between the first sliding reference line PRS1.

At least one of the first sliding angle AGS1, the second sliding angle AGS2, the third sliding angle AGS3, and the fourth sliding angle AGS4 is related to the first sliding angle AGS1, the second sliding angle AGS2, the third sliding angle AGS3, and the 4 Sliding angle AGS4 is another difference.

The first sliding angle AGS1 is preferably smaller than the second sliding angle AGS2 and the fourth sliding angle AGS4, respectively. The third sliding angle AGS3 is preferably smaller than the second sliding angle AGS2 and the fourth sliding angle AGS4, respectively.

Preferably, the first sliding angle AGS1 and the third sliding angle AGS3 are equal. Preferably, the second sliding angle AGS2 and the fourth sliding angle AGS4 are different. Preferably, the second sliding angle AGS2 is smaller than the fourth sliding angle AGS4.

When viewed from the first axial direction surface 38 toward the second axial direction surface 40 in the axial direction DA, the first sliding center point PS1 to the fourth sliding center point PS4 are arranged counterclockwise from the crank arm 4 in the circumferential direction DC The direction CCW preferably starts from the first sliding center point PS1 to the fourth sliding center point PS4.

The operation of the sprocket gear shifting mechanism 20 of this embodiment corresponds to the operation of the sprocket gear shifting mechanism 20 of the second embodiment.

The function of the bicycle front sprocket assembly 34 will be described. The driving force of one of the crank arm 4 and the crank shaft 2 is transmitted from the base member 44 to the front sprocket 6 via the sprocket carrier 42. The base member 44 slides on the sprocket carrier 42 at four locations. As mentioned above, at least one of the first sliding angle AGS1, the second sliding angle AGS2, the third sliding angle AGS3, and the fourth sliding angle AGS4 is the same as the first sliding angle AGS1, the second sliding angle AGS2, and the third sliding angle AGS3 , And the other of the fourth sliding angle AGS4. When the right crank arm 4 is stepped on and driven, the tension of the bicycle chain 10 is strongly applied to the sprocket teeth located between the first reference line LR1 and the second reference line LR2 used to define the first connection angle AG1. By reducing the first sliding angle AGS1, the rigidity of the sliding portion 52 when the right crank arm 4 is stepped on and driven can be increased. When the left crank arm 4 is stepped on and driven, the tension of the bicycle chain 10 is strongly applied to the sprocket teeth located between the third reference line LR3 and the fourth reference line LR4 used to define the third connection angle AG3. By reducing the third sliding angle AGS3, the rigidity of the sliding portion 52 when the left crank arm 4 is stepped on and driving can be increased. Therefore, by reducing at least one of the first sliding angle AGS1 and the third sliding angle AGS3, and it is more preferable to reduce both the first sliding angle AGS1 and the third sliding angle AGS3, the rigidity of the sprocket gear shifting mechanism can be improved.

<Fourth Embodiment> With reference to Fig. 17, a bicycle front sprocket assembly 34 including an example of the sprocket gear shift mechanism 20 will be described. The same reference numerals as those in the second embodiment are assigned to the structures common to the second embodiment, and overlapping descriptions are omitted.

The bicycle front sprocket assembly 34 includes a front sprocket 6 and a sprocket tooth shift mechanism 20.

The front sprocket 6 includes a sprocket body 36 and a plurality of sprocket teeth 18 arranged on the outer periphery of the sprocket body 36. The sprocket gear shift mechanism 20 includes a sprocket carrier 42 coupled to the front sprocket 6 and a base member 44 coupled to one of the crank arm 4 and the crank shaft 2.

The sprocket gear shift mechanism 20, in the assembled state of the bicycle front sprocket assembly 34 assembled on the crankshaft 2 and the crank arm 4, allows the plural sprocket teeth 18 of the front sprocket to rotate at least on the front sprocket 6 The axial direction DA of the central axis CA can be displaced relative to the above-mentioned one of the crank arm 4 and the crank shaft 2, and the sprocket carrier 42 can move relative to the base member 44.

The structure of the sprocket shift mechanism 20 is the same as that of the sprocket shift mechanism 20 of the second embodiment. The fastening structure of the front sprocket 6 and the base member 44 is not limited. The fastening structure of the front sprocket 6 and the base member 44 is preferably the same as the fastening structure exemplified in the second embodiment. The sliding structure of the base member 44 and the sprocket carrier 42 is not limited. The sliding structure of the base member 44 and the sprocket carrier 42 is preferably the same as the sliding structure exemplified in the third embodiment.

The base member 44 is attached to one of the crank shaft 2 and the crank arm 4. The base member 44 may be detachably connected to one of the crank shaft 2 and the crank arm 4 by spline engagement.

The sprocket body 36 includes at least one connecting portion 70X. The sprocket carrier 42 includes at least one additional connecting portion 60X.

At least one connecting portion 70X of the sprocket body 36 and at least one additional connecting portion 60X of the sprocket carrier 42 are coupled to each other by at least one fastening member 64.

The sprocket gear displacement mechanism 20 includes at least one sliding portion 52. The total number of at least one fastening member 64 is equal to the total number of at least one sliding portion 52.

At least one connecting portion 70X of the sprocket main body 36 includes a plurality of connecting portions. At least one additional connecting portion 60X of the sprocket main body 42 includes a plurality of connecting portions.

The at least one fastening member 64 includes a plurality of fastening members 64A, 64B, 64C, and 64D. The at least one sliding part 52 includes a plurality of sliding parts 52. The total number of the plural fastening parts is equal to the total number of the plural sliding parts 52.

The at least one sliding portion 52 is arranged near the at least one fastening member 64 in the assembled state. The at least one sliding portion 52 is arranged on the upstream side of the driving rotation direction with respect to the at least one fastening member 64 in the assembled state.

The operation of the sprocket gear shifting mechanism 20 of this embodiment corresponds to the operation of the sprocket gear shifting mechanism 20 of the second embodiment.

The function of the bicycle front sprocket assembly 34 will be described. The driving force of one of the crank arm 4 and the crank shaft 2 is transmitted from the base member 44 to the front sprocket 6 via the sprocket carrier 42. The base member 44 slides on the sprocket carrier 42 at four locations. As described above in the sprocket gear shift mechanism 20, at least one connecting portion 70X of the front sprocket 6 and at least one additional connecting portion 60X of the sprocket carrier 42 are coupled to each other by at least one fastening member 64. The total number of at least one fastening member 64 is equal to the total number of at least one sliding portion 52. Thereby, the driving force is transmitted from the base member 44 to the sprocket carrier 42 via the sliding portion 52 and the fastening member 64. The driving force is efficiently transmitted to the sprocket carrier 42 by the corresponding relationship between the sliding portion 52 and the fastening member 64. The driving force can be efficiently transmitted from the crankshaft 2 to the sprocket.

<Fifth Embodiment> With reference to FIGS. 18 to 23, a bicycle front sprocket assembly 34 including an example of the sprocket gear shift mechanism 20 will be described. The same reference numerals as those in the second embodiment are assigned to the structures common to the second embodiment, and overlapping descriptions are omitted.

The bicycle front sprocket assembly 34 includes a front sprocket 6 and a sprocket tooth shift mechanism 20.

The front sprocket 6 includes a sprocket body 36 and plural sprocket teeth 18 arranged on the outer circumference of the sprocket body 36 in the circumferential direction DC of the rotation center axis CA of the front sprocket 6.

The sprocket gear shift mechanism 20 includes a sprocket carrier 42 coupled to the front sprocket 6 and a base member 44 coupled to one of the crank arm 4 and the crank shaft 2 by groove engagement.

The sprocket gear shift mechanism 20, in the assembled state of the bicycle front sprocket assembly 34 assembled on the crankshaft 2 and the crank arm 4, allows the plural sprocket teeth 18 of the front sprocket to rotate at least on the front sprocket 6 The axial direction DA of the central axis CA can be displaced relative to the above-mentioned one of the crank arm 4 and the crank shaft 2, and the sprocket carrier 42 can move relative to the base member 44.

The structure of the sprocket shift mechanism 20 is the same as that of the sprocket shift mechanism 20 of the second embodiment. The fastening structure of the front sprocket 6 and the base member 44 is not limited. The fastening structure of the front sprocket 6 and the base member 44 is preferably the same as the fastening structure exemplified in the second embodiment. The sliding structure of the base member 44 and the sprocket carrier 42 is not limited. The sliding structure of the base member 44 and the sprocket carrier 42 is preferably the same as the sliding structure exemplified in the third embodiment.

The base member 44 is attached to one of the crank shaft 2 and the crank arm 4. The base member 44 may be detachably connected to one of the crank shaft 2 and the crank arm 4 by spline engagement.

As shown in Figs. 19 and 20, the plural sprocket teeth 18 have at least one first tooth 82 having the first maximum chain engagement axis width WA1 with respect to the rotation center axis CA, and relative to the rotation The central axis CA includes at least one second tooth 84 having the second maximum chain engagement axis width WA2. In the axis direction DA of the rotation center axis CA, the first maximum chain engagement axis direction width WA1 is greater than the second maximum chain engagement axis direction width WA2.

It is further provided with a locking member 46, which prevents the base member 44 from being displaced relative to one of the crank arm 4 and the crank shaft 2 in the assembled state and is engaged with one of the crank arm 4 and the crank shaft 2 .

As shown in Fig. 18, the first radial length LRS1 is defined as between the first radial outermost tooth end 82a of at least one first tooth 82 in the radial direction of the rotation center axis CA and the rotation center axis CA length. The second radial length LRS2 is defined as the length between the second radially outermost tooth end 84a of at least one second tooth 84 in the radial direction of the rotation center axis CA and the rotation center axis CA. The first radial length LRS1 is longer than the second radial length LRS2.

As shown in Fig. 21, the first largest chain engagement axis width WA1 is greater than: the inner link axial distance WAI defined between the pair of inner link pieces 92 of the bicycle chain 10 in the axial direction DA, and Less than: the outer link axial distance WAJ defined between the pair of outer link pieces 94 of the bicycle chain 10 in the axial direction DA. The second largest chain engagement axis width WA2 is smaller than the inner link axis interval WAI.

The first maximum chain engagement axis width WA1 of at least one first tooth 82 is preferably at least 75% of the outer link axis interval WAJ. The first maximum chain engagement axis width WA1 of at least one first tooth 82 is more preferably 80% or more of the outer link axis interval WAJ.

As shown in FIG. 19, the at least one first tooth 82 has a first axial direction tooth end center line LCRT1 offset from the first axial tooth center surface CST1 of the at least one first tooth 82 in the axial direction DA.

As shown in FIG. 20, at least one second tooth 84 has a second axial direction tooth end center line LCRT2 that is offset from the second axial tooth center surface CST2 of the at least one second tooth 84 in the axial direction DA.

As shown in FIG. 22, at least one first tooth 82 is asymmetrical in the circumferential direction DC with respect to the tooth bottom center line LCT1 in the first circumferential direction. Specifically, the size or shape of the driving surface of the first tooth 82 may be different from the non-driving surface of the first tooth 82. In this embodiment, the chamfer on the driving surface side of the first tooth 82 is larger than the chamfer on the non-driving surface of the first tooth 82. In another example, the curvature of the driving surface of the first tooth 82 may be different from the curvature of the non-driving surface.

As shown in FIG. 23, at least one second tooth 84 is asymmetrical in the circumferential direction DC with respect to the tooth bottom center line LCT2 in the second circumferential direction. Specifically, the size or shape of the driving surface of the second tooth 84 may be different from the non-driving surface of the second tooth 84. In this embodiment, a notch is formed in the driving surface of the tooth end of the second tooth 84, and no notch is formed in the non-driving surface of the tooth end of the second tooth 84. In another example, the curvature of the driving surface of the second tooth 84 may be different from the curvature of the non-driving surface.

As shown in FIG. 19, at least one first tooth 82 is asymmetrical with respect to the tooth bottom center surface CST1 in the first circumferential direction in the axial direction DA. As shown in FIG. 20, at least one second tooth 84 is asymmetrical with respect to the tooth bottom center surface CST2 in the second circumferential direction in the axial direction DA.

The at least one first tooth 82 includes a plurality of first teeth 82. The at least one second tooth 84 includes a plurality of second teeth 84. The plural first teeth 82 and the plural second teeth 84 are alternately arranged in the circumferential direction DC.

The operation of the sprocket gear shifting mechanism 20 of this embodiment corresponds to the operation of the sprocket gear shifting mechanism 20 of the second embodiment.

The function of the bicycle front sprocket assembly 34 will be described. The driving force of one of the crank arm 4 and the crank shaft 2 is transmitted from the sprocket to the double rear sprocket assembly 16 via the bicycle chain 10. The sprocket is moved in the axial direction DA of the rotation center axis CA by the sprocket gear shift mechanism 20. As described above, the plural sprocket teeth 18 have: at least one first tooth 82 having the first maximum chain engagement axis width WA1 relative to the rotation center axis CA, and at least one first tooth 82 relative to the rotation center axis CA. 2 The largest chain engages at least one second tooth 84 of the axial width WA2. In the axis direction DA of the rotation center axis CA, the first maximum chain engagement axis direction width WA1 is greater than the second maximum chain engagement axis direction width WA2. With this structure, the engagement force with respect to the bicycle chain 10 is increased. In particular, when the sprocket moves in the axial direction DA of the rotation center axis CA, by increasing the engagement force between the sprocket and the bicycle chain 10, the chain can be prevented from falling off and the driving efficiency can be improved.

A: Bicycle AC1: 1st common axis AC2: 2nd common axis AC3: 3rd common axis AC4: 4th common axis AF1: 1st fastening axis AF2: 2nd fastening axis AF3: 3rd fastening axis AF4: 4th fastening axis AF5: 5th fastening axis AF6: The sixth fastening axis AF7: 7th fastening axis AF8: 8th fastening axis AG1: The first connection angle AG2: 2nd connection angle AG3: 3rd connection angle AG4: 4th connection angle AGS1: first sliding angle AGS2: 2nd sliding angle AGS3: 3rd sliding angle AGS4: 4th sliding angle CA: Rotation center axis CS: Center plane CST1: Center surface of tooth bottom in the first axis direction CST2: 2nd axis direction tooth bottom center plane LA: axial length LCRT1: Centerline of tooth end in the first axis direction LCRT2: 2nd axis direction tooth end centerline LCT1: Centerline of tooth bottom in the first circle LCT2: Centerline of tooth bottom in the 2nd circle LR1: The first reference line LRS1: 1st radial length LR2: 2nd reference line LRS2: 2nd radial length LR3: 3rd reference line LR4: 4th reference line PCR: axis center point PCS: axial center plane PRS1: 1st sliding reference line PRS2: 2nd sliding reference line PRS3: 3rd sliding reference line PRS4: 4th sliding reference line PS1: The first sliding center point PS2: 2nd sliding center point PS3: 3rd sliding center point PS4: 4th sliding center point RD: Shift width in the direction of the main axis WA1: The first largest chain engagement axis width WA2: The second largest chain engagement axis width WAI: Interval of inner link axis direction WAJ: Interval of outer link axis direction 2: crankshaft 4: crank arm 6: Front sprocket 8: Rear sprocket 10: Bicycle chain 12: Bicycle drive system 14: Crank assembly 16: Duplex rear sprocket assembly 18: Sprocket 20: Sprocket gear shift mechanism 22: smallest rear sprocket 24: Largest rear sprocket 26: Middle rear sprocket 30: Outer part in the axial direction 32: axial inner face 34: Front sprocket assembly for bicycle 36: Sprocket body 38: 1st axis direction surface 40: 2nd axis direction plane 42: sprocket carrier 44: base member 46: Locking mechanism 52: Sliding part 52A: The first sliding part 52B: 2nd sliding part 52C: The third sliding part 52D: 4th sliding part 60: Connection 60E: 5th connection 60F: 6th connection part 60G: 7th connection part 60H: 8th connection part 60X: Additional connection part 64: Fastening member 64A: The first fastening member 64B: The second fastening member 64C: The third fastening member 64D: 4th fastening member 70A: The first connection part 70B: The second connection part 70C: 3rd connection part 70D: 4th connection part 70X: Connection part 82: 1st tooth 82a: 1st radial outermost tooth end 84: 2nd tooth 84a: 2nd radial outermost tooth end 92: inner link piece 94: Outer connecting rod piece

[Figure 1] is a schematic view of a bicycle including a bicycle drive system as viewed from above in relation to the first embodiment. [Figure 2] A schematic view of an example of a bicycle front sprocket assembly for a bicycle viewed from above. [Figure 3] A schematic view of another example of the bicycle front sprocket assembly for a bicycle viewed from above. [Figure 4] is a top view of the compound rear sprocket assembly. [Fig. 5 is a perspective view of a device including a bicycle front sprocket assembly according to the first to third embodiments. [Figure 6] is a side view of the device including the bicycle front sprocket assembly. [Figure 7] is an exploded perspective view of a device including a bicycle front sprocket assembly. [Figure 8] is an exploded perspective view of the sprocket gear shift mechanism. [Figure 9] is an exploded perspective view of the sliding part and the holding member. [Figure 10] is a cross-sectional view taken along line X-X in Figure 6. [Figure 11] is an enlarged view of a part of Figure 10. [Figure 12] is a side view of the front sprocket. [Figure 13] is a side view of the sprocket carrier. [Figure 14] is a side view of the assembly of the front sprocket and the sprocket carrier. [Figure 15] is a side view of the assembly of the front sprocket, sprocket gear shift mechanism, and crank arm. [Figure 16] is a cross-sectional view of the bicycle front sprocket assembly along the line XVI-XVI in Figure 6. [Figure 17] is a side view of a bicycle front sprocket assembly according to a fourth embodiment. [Figure 18] is a partial enlarged view of the front sprocket according to the fifth embodiment. [Figure 19] is a plan view of the first tooth. [Figure 20] is a plan view of the second tooth. [Figure 21] is a schematic diagram showing the arrangement relationship between the bicycle chain and the first and second teeth. [Figure 22] is a side view of the first tooth. [Figure 23] is a side view of the second tooth.

A: Bicycle

CA: Rotation center axis

CS: Center plane

DA: axis direction

PCR: axis center point

1: frame

2: crankshaft

4: crank arm

6: Front sprocket

8: Rear sprocket

10: Bicycle chain

12: Bicycle drive system

14: Crank assembly

16: Duplex rear sprocket assembly

18: Sprocket

20: Sprocket gear shift mechanism

Claims (44)

A driving system for bicycles, comprising: a crank assembly and a compound rear sprocket assembly including a plurality of rear sprocket wheels; The crank assembly includes: a front sprocket, a crank arm, and a sprocket that allows the sprocket of the front sprocket to be displaced relative to the crank arm at least in the axial direction of the rotation center axis of the front sprocket Position agency The plurality of rear sprockets include: a smallest rear sprocket, a largest rear sprocket, and at least 12 intermediate rear sprockets arranged in the axial direction between the smallest rear sprocket and the largest rear sprocket; The plurality of rear sprockets respectively have an axial outer surface and an axial inner surface with respect to the rotation center axis; The length between the axial outer surface of the smallest rear sprocket in the axial direction and the axial inner surface of the largest rear sprocket is defined as the axial length, and the axial length is 47.5 mm or more. The bicycle drive system of claim 1, wherein the axial length is 48 mm or more. The bicycle drive system according to claim 2, wherein the axial length is 49 mm or more. The bicycle drive system according to any one of claims 1 to 3, wherein the gear ratio of the total number of teeth of the largest rear sprocket to the total number of teeth of the smallest rear sprocket is 3.4 or more. The bicycle drive system according to any one of claims 1 to 3, wherein the value obtained by dividing the total number of the plurality of rear sprockets by the axial length is defined as the sprocket density, The above-mentioned sprocket density is 0.28 or more. Such as the bicycle drive system of any one of claims 1 to 3, wherein the minimum number of total teeth of the rear sprocket is 12 or less, The total number of teeth of the maximum rear sprocket is 42 or more. The bicycle drive system according to any one of claims 1 to 3, wherein the total number of the plurality of rear sprockets is 14 or more. The bicycle drive system according to any one of claims 1 to 3, wherein the front sprocket is a single front sprocket. The bicycle drive system according to any one of claims 1 to 3, wherein the displacement width of the front sprocket with respect to the overall axis of the crank arm caused by the sprocket gear displacement mechanism is from 5mm to 30mm range. The bicycle drive system according to any one of claims 1 to 3, wherein the bicycle drive system is mounted on a bicycle, and the front sprocket is opposite to the front sprocket caused by the sprocket gear shift mechanism The state in which the displacement width of the crank arm in the overall axis direction is located at the center point in the axial direction, At least five of the intermediate rear sprockets are arranged in the axial direction between the largest rear sprockets and the axial center surfaces of the front sprockets. A front sprocket assembly for bicycles, including: a front sprocket, and a sprocket tooth displacement mechanism; The front sprocket includes: a sprocket body, and a plurality of sprocket teeth arranged on the outer periphery of the sprocket body; the sprocket body includes: a first coupling portion having a first fastening axis, and a second fastening The second connecting portion of the axis, the third connecting portion with the third fastening axis, and the fourth connecting portion with the fourth fastening axis; The above-mentioned sprocket tooth displacement mechanism includes: a sprocket carrier and a base member; The sprocket carrier is coupled to the front sprocket; the base member is coupled to one of the crank arm and the crank shaft; In the sprocket displacement mechanism, in the assembled state of the bicycle front sprocket assembly assembled to the crankshaft and the crank arm, the plurality of sprocket teeth of the front sprocket rotate at least on the front sprocket The axial direction of the central axis can be displaced with respect to one of the crank arm and the crank shaft; The sprocket carrier is movable relative to the base member, The sprocket carrier includes: a fifth connection portion having a fifth fastening axis, a sixth connection portion having a sixth fastening axis, a seventh connection portion having a seventh fastening axis, and a seventh connection portion having a seventh fastening axis; The 8th connecting part of the tightening shaft; The second connecting portion is separated from the first connecting portion in the circumferential direction of the rotation center axis of the front sprocket and there is no other connecting portion therebetween; The third connecting portion is separated from the second connecting portion in the circumferential direction and there is no other connecting portion therebetween; The fourth connecting portion is separated from the first connecting portion and the third connecting portion in the circumferential direction and there is no other connecting portion therebetween, and in the assembled state, the crank arm is positioned at the first connecting portion in the circumferential direction. Between the connecting portion and the fourth connecting portion; The sixth connecting portion is separated from the fifth connecting portion in the circumferential direction and there is no other connecting portion therebetween; The seventh connecting portion is separated from the sixth connecting portion in the circumferential direction and there is no other connecting portion therebetween; The eighth connecting portion is separated from the fifth connecting portion and the seventh connecting portion in the circumferential direction and there is no other connecting portion therebetween, and in the assembled state, the crank arm is positioned at the fifth connecting portion in the circumferential direction. Between the connecting portion and the 8th connecting portion; The first fastening axis of the first connecting portion and the fifth fastening axis of the fifth connecting portion are made to be aligned with respect to the first common axis so that the first fastening member passes through the first connecting portion And at least one of the above-mentioned fifth connecting parts; The second fastening axis of the second connecting portion and the sixth fastening axis of the sixth connecting portion are made to be aligned with each other with respect to the second common axis so that the second fastening member passes through the second connecting portion And at least one of the above-mentioned sixth connecting parts; The third fastening axis of the third connecting portion and the seventh fastening axis of the seventh connecting portion are made to be aligned with respect to the third common axis so that the third fastening member passes through the third connecting portion And at least one of the above-mentioned seventh connecting parts; The fourth fastening axis of the fourth connecting portion and the eighth fastening axis of the eighth connecting portion are made to be aligned with respect to the fourth common axis so that the fourth fastening member passes through the fourth connecting portion And at least one of the above-mentioned eighth connecting parts; The first connection angle is used to prevent the other common axis from being located between the first common axis and the second common axis in the circumferential direction, but is defined as from the rotation center axis toward the first in the circumferential direction 1 The angle between the first reference line extending from the common axis and the second reference line extending from the rotation center axis toward the second common axis; The second connection angle is used to prevent the other common axis from being located between the second common axis and the third common axis in the circumferential direction, and is defined as the rotation from the second reference line in the circumferential direction The angle between the third reference lines extending from the central axis toward the third common axis; The third connection angle is used to prevent the other common axis from being located between the third common axis and the fourth common axis in the circumferential direction, but is defined as the rotation from the third reference line in the circumferential direction The angle between the fourth reference line extending from the central axis toward the fourth common axis; The fourth connection angle is used to prevent the other common axis from being located between the fourth common axis and the first common axis in the circumferential direction, but is defined as the fourth reference line and the first in the circumferential direction. The angle between the reference lines; At least one of the first connection angle, the second connection angle, the third connection angle, and the fourth connection angle is connected to the first connection angle, the second connection angle, the third connection angle, and the The other of the fourth connection angles is different. The bicycle front sprocket assembly according to claim 11, wherein the first connection angle is smaller than the second connection angle and the fourth connection angle, respectively. The bicycle front sprocket assembly of claim 11 or 12, wherein the third connection angle is smaller than the second connection angle and the fourth connection angle, respectively. The bicycle front sprocket assembly according to claim 11 or 12, wherein the first connection angle is equal to the third connection angle. The bicycle front sprocket assembly according to claim 11 or 12, wherein the second connection angle is different from the fourth connection angle. The bicycle front sprocket assembly according to claim 15, wherein the second connection angle is smaller than the fourth connection angle. The bicycle front sprocket assembly according to claim 11 or 12, wherein the front sprocket has: a first axial direction surface and a second axial direction surface opposite to the first axial direction surface in the axial direction ； The second axial direction surface faces the center surface of the bicycle when the bicycle front sprocket assembly is mounted on the bicycle; The first to fourth common shaft centers, when viewed from the first axial direction surface to the second axial direction surface in the axial direction, the first to fourth axial directions from the crank arm in the counterclockwise direction in the circumferential direction Arrange the common axis in order. The bicycle front sprocket assembly according to claim 11 or 12, wherein the base member is detachably connected to one of the crank shaft and the crank arm by a spline engagement method. A front sprocket assembly for bicycles, including: a front sprocket, and a sprocket tooth displacement mechanism; The front sprocket includes: a sprocket body and a plurality of sprocket teeth arranged on the outer periphery of the sprocket body; The above-mentioned sprocket tooth displacement mechanism includes: a sprocket carrier and a base member; The sprocket carrier is combined with the front sprocket; The above-mentioned base member is combined with one of the crank arm and the crank shaft; In the sprocket displacement mechanism, in the assembled state of the bicycle front sprocket assembly assembled to the crankshaft and the crank arm, the plurality of sprocket teeth of the front sprocket rotate at least on the front sprocket The axial direction of the central axis can be displaced with respect to one of the crank arm and the crank shaft; The sprocket carrier can move relative to the base member; The sprocket gear displacement mechanism includes: a first sliding part having a first sliding center point, a second sliding part having a second sliding center point, a third sliding part having a third sliding center point, and a fourth sliding part having a The fourth sliding part of the sliding center point; The second sliding portion is separated from the first sliding portion in the circumferential direction of the rotation center axis of the front sprocket and there is no other connecting portion therebetween; The third sliding portion is separated from the second sliding portion in the circumferential direction and there is no other connecting portion therebetween; The fourth sliding portion is used for positioning the crank arm between the first sliding portion and the fourth sliding portion in the circumferential direction in the assembled state, and is respectively connected to the first sliding portion and the third sliding portion in the circumferential direction. The sliding parts are separated and there are no other connecting parts between them; The first sliding angle is used to prevent other sliding center points from being located between the first sliding center point and the second sliding center point in the circumferential direction, but is defined as the rotation center axis toward the first sliding center in the circumferential direction. 1 The angle between the first sliding reference line extending from the sliding center point and the second sliding reference line extending from the rotation center axis toward the second sliding center point; The second sliding angle is used to prevent other sliding center points from being located between the second sliding center point and the third sliding center point in the circumferential direction, but is defined as the second sliding reference line in the circumferential direction and from the above The angle between the third sliding reference lines extending from the rotation center axis toward the third sliding center point; The third sliding angle is used to prevent other sliding center points from being located between the third sliding center point and the fourth sliding center point in the circumferential direction, but is defined as the third sliding reference line in the circumferential direction and from the above The angle between the fourth sliding reference line extending from the rotation center axis toward the fourth sliding center point; The fourth sliding angle is used to prevent other sliding center points from being located between the fourth sliding center point and the first sliding center point in the circumferential direction, but is defined as the fourth sliding reference line in the circumferential direction and the first sliding center point. 1 The angle between the sliding reference lines; At least one of the first sliding angle, the second sliding angle, the third sliding angle, and the fourth sliding angle is related to the first sliding angle, the second sliding angle, the third sliding angle, and the Another of the fourth sliding angles is different. The bicycle front sprocket assembly according to claim 19, wherein the first sliding angle is smaller than the second sliding angle and the fourth sliding angle, respectively. The bicycle front sprocket assembly according to claim 19 or 20, wherein the third sliding angle is smaller than the second sliding angle and the fourth sliding angle, respectively. The bicycle front sprocket assembly according to claim 19 or 20, wherein the first sliding angle is equal to the third sliding angle. The bicycle front sprocket assembly according to claim 19 or 20, wherein the second sliding angle is different from the fourth sliding angle. The bicycle front sprocket assembly according to claim 19 or 20, wherein the second sliding angle is smaller than the fourth sliding angle. The bicycle front sprocket assembly according to claim 19 or 20, wherein the front sprocket has: a first axial direction surface and a second axial direction surface opposite to the first axial direction surface in the axial direction ； The second axial direction surface faces the center surface of the bicycle when the bicycle front sprocket assembly is mounted on the bicycle; When the first to fourth sliding center points are viewed in the axial direction from the first axial direction surface to the second axial direction surface, in the circumferential direction from the crank arm to the counterclockwise direction from the crank arm to the first to fourth Sequential configuration of sliding center points. The bicycle front sprocket assembly of claim 19 or 20, wherein the base member is detachably connected to one of the crank shaft and the crank arm by a spline engagement method. A front sprocket assembly for bicycles, including: a front sprocket, and a sprocket tooth displacement mechanism; The front sprocket includes: a sprocket body and a plurality of sprocket teeth arranged on the outer circumference of the sprocket body; the sprocket body includes at least one connecting portion; The above-mentioned sprocket tooth displacement mechanism includes: a sprocket carrier and a base member; The sprocket carrier is combined with the front sprocket; The above-mentioned base member is combined with one of the crank arm and the crank shaft; In the sprocket displacement mechanism, in the assembled state of the bicycle front sprocket assembly assembled to the crankshaft and the crank arm, the plurality of sprocket teeth of the front sprocket rotate at least on the front sprocket The axial direction of the central axis can be displaced with respect to one of the crank arm and the crank shaft; The sprocket carrier can move relative to the base member; The sprocket carrier includes at least one additional connection part; The at least one connecting portion and the at least one additional connecting portion are combined with each other by at least one fastening member; The aforementioned sprocket tooth displacement mechanism includes at least one sliding part; The total number of the at least one fastening member is equal to the total number of the at least one sliding portion. The bicycle front sprocket assembly according to claim 27, wherein the base member is detachably connected to one of the crankshaft and the crank arm by a spline engagement method. The bicycle front sprocket assembly of claim 27 or 28, wherein the at least one connecting portion includes a plurality of connecting portions, The aforementioned at least one additional connecting portion includes a plurality of connecting portions, The above at least one fastening member includes a plurality of fastening members, The at least one sliding portion includes a plurality of sliding portions, The total number of the plurality of fastening members is equal to the total number of the plurality of sliding parts. The bicycle front sprocket assembly according to claim 27 or 28, wherein the at least one sliding portion is arranged in the vicinity of the at least one fastening member in the assembled state. The bicycle front sprocket assembly according to claim 27 or 28, wherein the at least one sliding portion is arranged on the upstream side in the driving rotation direction with respect to the at least one fastening member in the assembled state. A front sprocket assembly for bicycles, including: a front sprocket and a sprocket tooth displacement mechanism; The front sprocket includes a sprocket body and a plurality of sprocket teeth arranged on the outer circumference of the sprocket body in the circumferential direction of the rotation center axis of the front sprocket; The plurality of sprocket teeth have: at least one first tooth having a first maximum chain engagement axis width relative to the rotation center axis, and at least one first tooth having a second maximum chain engagement axis width relative to the rotation center axis At least one second tooth of the axial width; In the axial direction of the rotation center axis, the width of the first maximum chain engagement axis is greater than the width of the second maximum chain engagement axis; The above-mentioned sprocket tooth displacement mechanism includes: a sprocket carrier and a base member; The sprocket carrier is combined with the front sprocket; The base member is connected to one of the crank arm and the crank shaft by groove engagement; In the sprocket displacement mechanism, in the assembled state of the bicycle front sprocket assembly assembled to the crankshaft and the crank arm, the plurality of sprocket teeth of the front sprocket rotate at least on the front sprocket The axial direction of the central axis can be displaced with respect to one of the crank arm and the crank shaft; The sprocket carrier is movable relative to the base member. The bicycle front sprocket assembly according to claim 32, wherein the base member is detachably connected to one of the crankshaft and the crank arm by a spline engagement method. For example, the bicycle front sprocket assembly of claim 32 or 33, which further includes a locking member, The lock member is used for restraining the displacement of the base member with respect to the one of the crank arm and the crank shaft in the assembled state, and engages with the one of the crank arm and the crank shaft. The bicycle front sprocket assembly according to claim 32 or 33, wherein the first maximum chain engagement axis width is greater than: defined by a pair of inner link pieces of the bicycle chain in the axial direction The axial distance of the inner connecting rod is smaller than: the outer connecting rod axial distance defined between a pair of outer connecting rod pieces of the above-mentioned axial direction bicycle chain; The width in the axis direction of the second largest chain engagement axis is smaller than the interval in the axis direction of the inner link. The bicycle front sprocket assembly of claim 32 or 33, wherein the first radial length is defined as the first radially outermost tooth end of the at least one first tooth in the radial direction of the rotation center axis The length from the axis of the aforementioned rotation center; The second radial length is defined as the length between the second radially outermost tooth end of the at least one second tooth in the radial direction of the rotation center axis and the rotation center axis; The first radial length is greater than the second radial length. The bicycle front sprocket assembly according to claim 35, wherein the first maximum chain engagement axis width of the at least one first tooth is 75% or more of the axial interval of the outer link. The bicycle front sprocket assembly according to claim 32 or 33, wherein the at least one first tooth has a first tooth that is offset from the center surface of the tooth bottom in the first axial direction of the at least one first tooth in the axial direction The center line of the tooth end in the 1 axis direction. The bicycle front sprocket assembly according to claim 32 or 33, wherein the at least one second tooth has: a second tooth that is offset from the center surface of the tooth bottom in the second axial direction of the at least one second tooth in the axial direction The center line of the tooth end in the 2-axis direction. The bicycle front sprocket assembly according to claim 32 or 33, wherein the at least one first tooth is asymmetric in the circumferential direction with respect to the tooth bottom center line in the first circumferential direction. The bicycle front sprocket assembly according to claim 32 or 33, wherein the at least one second tooth is asymmetric in the circumferential direction with respect to the tooth bottom center line in the second circumferential direction. The bicycle front sprocket assembly according to claim 32 or 33, wherein the at least one first tooth is asymmetrical in the axial direction with respect to the center surface of the tooth bottom in the first axial direction. The bicycle front sprocket assembly according to claim 32 or 33, wherein the at least one second tooth is asymmetric in the axial direction with respect to the center surface of the tooth bottom in the second axial direction. According to claim 32 or 33, the bicycle front sprocket assembly, wherein the at least one first tooth includes plural first teeth, The at least one second tooth includes a plurality of second teeth, The plurality of first teeth and the plurality of second teeth are alternately arranged in the circumferential direction.

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