TWI871451B - Front sprocket assembly for human-powered vehicle, and crank assembly for human-powered vehicle - Google Patents

Abstract

A front sprocket assembly for a human-powered vehicle comprises a front sprocket and a sprocket gear shifting mechanism. The front sprocket comprises a sprocket body and a plurality of sprocket teeth arranged on the outer periphery of the sprocket body. The sprocket gear shifting mechanism includes: a sprocket carrier coupled to the sprocket body in a torque transmission state, and a base member detachably coupled to the electric auxiliary drive unit for a human-powered vehicle in a torque transmission state; in an assembled state of the front sprocket assembly and the electric auxiliary drive unit, the sprocket carrier can move relative to the base member, and a plurality of sprocket teeth of the front sprocket can be shifted relative to the electric auxiliary drive unit at least in an axial direction relative to the rotation center axis of the front sprocket.

Description

Front sprocket assembly for human-powered vehicle, and crank assembly for human-powered vehicle

The present invention relates to a front sprocket assembly for a human-powered vehicle and a crank assembly for a human-powered vehicle.

Patent document 1 discloses a front sprocket assembly for a bicycle, which allows the front sprocket to shift toward the axis in response to the movement of the chains between a plurality of rear sprockets.

[Prior Art Literature] [Patent Literature]

[Patent Document 1] Specification of U.S. Patent Application Publication No. 2013/0008282

One purpose of the present invention is to provide a front sprocket assembly for a human-powered vehicle and a crank assembly for a human-powered vehicle, which can be applied to a human-powered vehicle with an electric auxiliary drive unit and has excellent chain retention force.

The first type of front sprocket assembly for a human-driven vehicle of the present invention comprises: a front sprocket and a sprocket gear shifting mechanism; the front sprocket comprises: a sprocket body, and a plurality of sprocket gears arranged on the outer periphery of the sprocket body in the circumferential direction relative to the rotation center axis of the front sprocket; the sprocket gear shifting mechanism comprises: a sprocket carrier coupled to the sprocket body of the front sprocket in a torque transmission state, and A base member that can be detachably coupled to an electric auxiliary drive unit for a human-powered vehicle in a torque transmission state; in the assembled state of the front sprocket assembly and the electric auxiliary drive unit, the sprocket carrier can move relative to the base member, and the plurality of sprocket teeth of the front sprocket can be displaced relative to the electric auxiliary drive unit at least in the axial direction of the front sprocket relative to the rotation center axis.

The first type of front sprocket assembly can improve the chain holding force of a human-powered vehicle with an electric auxiliary drive unit. In addition, in a human-powered vehicle with an electric auxiliary drive unit, the reduction in driving efficiency can be suppressed by properly maintaining the chain path. Therefore, the wear of the chain and sprocket can be suppressed.

According to the second type of the first type of the present invention, the base component of the sprocket gear shifting mechanism has a drive unit engagement portion, and the drive unit engagement portion can be detachably engaged with the sprocket assembly engagement portion of the electric auxiliary drive unit in the state of torque transmission.

The second type of front sprocket assembly can improve the chain holding force of a human-driven vehicle with an electric assist drive unit. In addition, in a human-driven vehicle with an electric assist drive unit, the reduction in driving efficiency can be suppressed by properly maintaining the chain path. Therefore, the wear of the chain and sprocket can be suppressed.

According to the third type of the second type of the present invention, the drive unit engagement portion of the base member can be detachably engaged with the sprocket assembly engagement portion provided on the output shaft of the electric auxiliary drive unit in the state of torque transmission; thereby, the base member of the sprocket gear shifting mechanism is indirectly coupled to the crank axle and the crank arm in the state of transmitting torque via the output shaft during pedaling.

The third type of front sprocket assembly can improve the chain holding force of a human-driven vehicle with an electric auxiliary drive unit. In addition, in a human-driven vehicle with an electric auxiliary drive unit, the reduction in driving efficiency can be suppressed by properly maintaining the chain path. Therefore, the wear of the chain and sprocket can be suppressed.

According to the fourth type of the third type of the present invention, the front sprocket assembly further has a locking member, which, in the assembled state, fixes the base member to the output shaft of the electric auxiliary drive unit to limit the axial movement of the base member relative to the rotation center axis.

The fourth type of front sprocket assembly allows the front sprocket assembly to be easily installed and removed from the electric auxiliary drive unit. Furthermore, the front sprocket assembly can be stably installed on the electric auxiliary drive unit by limiting the axial movement of the base member by the locking member.

According to the front sprocket assembly of the fourth and fifth aspects of the present invention, the locking member comprises: a cylindrical main body having a central axis, and a protrusion extending radially outward from the cylindrical main body relative to the central axis of the cylindrical main body; the cylindrical main body has a male threaded portion, and the male threaded portion is used to engage with the female threaded portion of the output shaft provided on the electric auxiliary drive unit; the protrusion abuts against the base member in the assembled state.

The fifth type of front sprocket assembly allows the front sprocket assembly to be easily mounted and dismounted relative to the electric auxiliary drive unit by rotating the locking member relative to the output shaft.

According to the sixth type of the front sprocket assembly of any one of the first to fifth types of the present invention, the sprocket body includes: a first connecting portion having a first fastening axis, a second connecting portion having a second fastening axis, a third connecting portion having a third fastening axis, and a fourth connecting portion having a fourth fastening axis; the sprocket carrier includes: a fifth connecting portion having a fifth fastening axis, a sixth connecting portion having a sixth fastening axis, a seventh connecting portion having a seventh fastening axis The 7th connecting part and the 8th connecting part having the 8th fastening axis; the 2nd connecting part is arranged to be separated from the 1st connecting part in the circumferential direction relative to the rotation center axis of the front sprocket and there is no other connecting part between them; the 3rd connecting part is arranged to be separated from the 2nd connecting part in the circumferential direction and there is no other connecting part between them; the 4th connecting part is arranged to be respectively connected to the 1st connecting part and the 4th connecting part in the circumferential direction. The third connecting part is separated from the third connecting part and there is no other connecting part between them; the sixth connecting part is arranged in the circumferential direction to be separated from the fifth connecting part and there is no other connecting part between them; the seventh connecting part is arranged in the circumferential direction to be separated from the sixth connecting part and there is no other connecting part between them; the eighth connecting part is arranged in the circumferential direction to be separated from the fifth connecting part and the seventh connecting part respectively and there is no other connecting part between them; The first fastening axis of the first connecting part and the fifth fastening axis of the fifth connecting part are aligned with each other relative to the first common axis so that the first fastening member passes through at least one of the first connecting part and the fifth connecting part; the second fastening axis of the second connecting part and the sixth fastening axis of the sixth connecting part are aligned with each other relative to the second common axis so that the second fastening member passes through the second connecting part and the sixth connecting part. at least one of the connecting parts; the third fastening axis of the third connecting part and the seventh fastening axis of the seventh connecting part are aligned with each other relative to the third common axis so that the third fastening member passes through at least one of the third connecting part and the seventh connecting part; the fourth fastening axis of the fourth connecting part and the eighth fastening axis of the eighth connecting part are aligned with each other relative to the fourth common axis so that the fourth fastening member Through at least one of the fourth connecting portion and the eighth connecting portion; the first connecting angle is defined as: the angle between the first reference line extending from the rotation center axis toward the first common axis in the circumferential direction and the second reference line extending from the rotation center axis toward the second common axis, so that other common axes are not located between the first common axis and the second common axis in the circumferential direction; the second connecting angle is defined as : The angle between the second reference line in the circumferential direction and the third reference line extending from the rotation center axis toward the third common axis is used to make the other common axis not located between the second common axis and the third common axis in the circumferential direction; the third connection angle is 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 is used to make the other common axis not located between the second common axis and the third common axis in the circumferential direction. The common axis is not located between the third common axis and the fourth common axis in the circumferential direction; the fourth connection angle is defined as the angle between the fourth reference line and the first reference line in the circumferential direction, which is used to make other common axes not located between the fourth common axis and the first common axis in the circumferential direction; the first connection angle, the second connection angle, the third connection angle, and the fourth connection angle are equal to each other.

With the sixth type of front sprocket assembly, the sprocket carrier is connected to the sprocket body at four locations arranged at equal angles in the circumferential direction. This improves the rigidity of the front sprocket assembly and the transmission efficiency of the driving force.

According to the 6th and 7th types of the front sprocket assembly of the present invention, the front sprocket has: a first axial surface, and a second axial surface on the opposite side of the first axial surface in the axial direction; the second axial surface is opposite to the axial center surface of the human-powered vehicle relative to the rotation center axis when the front sprocket assembly is mounted on the human-powered vehicle; the first to fourth common axes are arranged in the order of the first to fourth common axes in the circumferential direction from the crank arm toward the counterclockwise direction when the first axial surface is observed toward the second axial surface in the axial direction.

The 7th type of front sprocket assembly can improve the rigidity of the front sprocket assembly and the transmission efficiency of the driving force.

According to the 8th type of the front sprocket assembly of the 6th or 7th type of the present invention, the sprocket gear shifting mechanism includes: a first sliding portion having a first sliding center point, a second sliding portion having a second sliding center point, a third sliding portion having a third sliding center point, and a fourth sliding portion having a fourth sliding center point; the second sliding portion is arranged in the circumferential direction relative to the rotation center axis of the front sprocket to be separated from the first sliding portion and there is no other sliding portion between them; the third sliding portion is arranged in the circumferential direction, The fourth sliding portion is configured to be separated from the first sliding portion and the third sliding portion in the circumferential direction and there is no other sliding portion therebetween; the first sliding angle 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, so that other sliding center points are not located above the first sliding center point in the circumferential direction. The second sliding angle is defined as the angle between the second sliding reference line and the third sliding reference line extending from the rotation center axis toward the third sliding center point in the circumferential direction, so that other sliding center points are not located between the second sliding center point and the third sliding center point in the circumferential direction; the third sliding angle is defined as the angle between the third sliding reference line and the fourth sliding reference line extending from the rotation center axis toward the fourth sliding center point in the circumferential direction. The angle between the sliding reference lines is used to make other sliding center points not located between the third sliding center point and the fourth sliding center point in the circumferential direction; the fourth sliding angle is defined as: the angle between the fourth sliding reference line and the first sliding reference line in the circumferential direction is used to make other sliding center points not located between the fourth sliding center point and the first sliding center point in the circumferential direction; the first sliding angle, the second sliding angle, the third sliding angle, and the fourth sliding angle are equal to each other.

With the 8th type front sprocket assembly, the sprocket gear shifting mechanism can perform smooth sliding motion because the four sliding parts are arranged at equal angles in the circumferential direction.

According to the 8th and 9th types of the front sprocket assembly of the present invention, the first sliding portion is arranged on the upstream side of the driving rotation direction of the front sprocket relative to the first fastening member in the above-mentioned assembly state, the second sliding portion is arranged on the upstream side of the driving rotation direction of the front sprocket relative to the second fastening member in the above-mentioned assembly state, the third sliding portion is arranged on the upstream side of the driving rotation direction of the front sprocket relative to the third fastening member in the above-mentioned assembly state, and the fourth sliding portion is arranged on the upstream side of the driving rotation direction of the front sprocket relative to the fourth fastening member in the above-mentioned assembly state.

The 9th type front sprocket assembly makes it easy to transmit the driving force to the fastening member and difficult to transmit the driving force to the sliding part. Therefore, the sprocket gear shifting mechanism can achieve smooth sliding action, which can improve the transmission efficiency of the driving force.

According to the 10th type of the front sprocket assembly of the 8th or 9th type of the present invention, in the above-mentioned assembled state and when observed from the radial direction relative to the above-mentioned rotation center axis, the above-mentioned first sliding portion partially overlaps with the above-mentioned first fastening member in the above-mentioned circumferential direction; in the above-mentioned assembled state and when observed from the above-mentioned radial direction, the above-mentioned second sliding portion partially overlaps with the above-mentioned second fastening member in the above-mentioned circumferential direction; in the above-mentioned assembled state and when observed from the above-mentioned radial direction, the above-mentioned third sliding portion partially overlaps with the above-mentioned third fastening member in the above-mentioned circumferential direction; in the above-mentioned assembled state and when observed from the above-mentioned radial direction, the above-mentioned fourth sliding portion partially overlaps with the above-mentioned fourth fastening member in the above-mentioned circumferential direction.

With the 10th type of front sprocket assembly, since the positions of each sliding part and the corresponding fastening member are close to each other in the circumferential direction, the sprocket gear shifting mechanism can achieve smooth sliding action, which can improve the transmission efficiency of the driving force.

According to the 11th type of the front sprocket assembly of any one of the 1st to 7th types of the present invention, the sprocket gear shifting mechanism includes: a first sliding portion having a first sliding center point, a second sliding portion having a second sliding center point, a third sliding portion having a third sliding center point, and a fourth sliding portion having a fourth sliding center point; the second sliding portion is arranged in the circumferential direction of the front sprocket relative to the rotation center axis to be separated from the first sliding portion and there is no other sliding portion between them; the third sliding portion is arranged in the circumferential direction of the front sprocket relative to the rotation center axis to be separated from the first sliding portion and there is no other sliding portion between them; The fourth sliding portion is arranged in the circumferential direction to be separated from the first sliding portion and the third sliding portion, respectively, and there is no other sliding portion therebetween; the first sliding angle 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, so as to prevent other sliding center points from sliding in the circumferential direction. The second sliding angle is defined as the angle between the second sliding reference line in the circumferential direction and the third sliding reference line extending from the rotation center axis toward the third sliding center point, so that other sliding center points are not located between the second sliding center point and the third sliding center point in the circumferential direction; the third sliding angle is defined as the angle between the third sliding reference line in the circumferential direction and the third sliding reference line extending from the rotation center axis toward the fourth sliding center point. The angle between the fourth sliding reference line is used to make other sliding center points not located between the third sliding center point and the fourth sliding center point in the circumferential direction; the fourth sliding angle is defined as: the angle between the fourth sliding reference line and the first sliding reference line in the circumferential direction is used to make other sliding center points not located between the fourth sliding center point and the first sliding center point in the circumferential direction; the first sliding angle, the second sliding angle, the third sliding angle, and the fourth sliding angle are equal to each other.

With the 11th type of front sprocket assembly, the sprocket gear shifting mechanism can perform smooth sliding motion because the four sliding parts are arranged at equal angles in the circumferential direction.

According to the 11th and 12th types of the front sprocket assembly of the present invention, the front sprocket has: a first axial surface, and a second axial surface on the opposite side of the first axial surface in the axial direction; the second axial surface is opposite to the axial center surface of the human-driven vehicle relative to the rotation center axis when the front sprocket assembly is mounted on the human-driven vehicle; the first to fourth sliding center points are arranged in the order of the first to fourth sliding center points in the circumferential direction from the crank arm toward the counterclockwise direction when the first axial surface is observed toward the second axial surface in the axial direction.

The 12th type front sprocket assembly allows the sprocket gear shifting mechanism to perform smooth sliding motion.

According to the 12th and 13th types of the front sprocket assembly of the present invention, when viewed from the first axial direction surface toward the second axial direction surface in the axial direction, the fourth sliding center point at least partially overlaps with the crank arm.

By using the 13th type of front sprocket assembly, the sliding parts can be evenly arranged in the circumferential direction, so the sliding property and rigidity of the sprocket tooth shifting mechanism can be improved.

According to the 14th type of front sprocket assembly of any one of the 1st to 13th types of the present invention, the plurality of sprocket teeth include: at least one first tooth having a first maximum chain engagement axial direction width relative to the rotation center axis, and at least one second tooth having a second maximum chain engagement axial direction width relative to the rotation center axis; in the axial direction relative to the rotation center axis, the first maximum chain engagement axial direction width is greater than the second maximum chain engagement axial direction width.

The 14th type front sprocket assembly can effectively hold the outer chain with the first tooth and the inner chain with the second tooth, thereby improving the chain holding force.

According to the 14th and 15th types of the front sprocket assembly of the present invention, the first maximum chain engagement axial direction width is greater than: the inner chain axis direction interval defined between a pair of inner chain plates of a human-driven vehicle chain in the above-mentioned axial direction, and less than: the outer chain axis direction interval defined between a pair of outer chain plates of the human-driven vehicle chain in the above-mentioned axial direction; the second maximum chain engagement axial direction width is less than the inner chain axis direction interval.

The 15th type front sprocket assembly can effectively hold the outer chain with the first tooth and the inner chain with the second tooth, thereby improving the chain holding force.

According to the 15th and 16th types of the front chain wheel assembly of the present invention, the first maximum chain engagement axis direction width of the at least one first tooth is more than 75% of the spacing in the outer chain axis direction.

The 16th type front sprocket assembly can more effectively hold the outer link of the chain with the first tooth, which can improve the chain holding force.

According to the 17th type of front sprocket assembly of any one of the 14th to 16th types of the present invention, the first radial length is defined as the length between the first radial outermost tooth end of the at least one first tooth and the above-mentioned rotation center axis in the radial direction relative to the above-mentioned rotation center axis; the second radial length is defined as the length between the second radial outermost tooth end of the at least one second tooth and the above-mentioned rotation center axis in the radial direction relative to the above-mentioned rotation center axis; the first radial length is greater than the second radial length.

With the 17th type front sprocket assembly, the chain first engages with the 1st tooth and then with the 2nd tooth, so the chain can continue to be stably engaged with the sprocket teeth. Therefore, the holding force of the chain can be improved.

According to the 17th and 18th types of the front sprocket assembly of the present invention, the second radial length is in the range of 75% to 95% of the first radial length.

With the 18th type front sprocket assembly, the chain first engages with the 1st tooth and then with the 2nd tooth, so the chain can continue to be stably engaged with the sprocket teeth. Therefore, the holding force of the chain can be improved.

According to the 19th type of front sprocket assembly of any one of the 14th to 18th types of the present invention, the at least one first tooth includes a plurality of first teeth, the at least one second tooth includes a plurality of second teeth, and the plurality of first teeth and the plurality of second teeth are alternately arranged in the circumferential direction.

The 19th type front sprocket assembly can effectively hold the outer chain with the first tooth and the inner chain with the second tooth, thereby improving the chain holding force.

The 20th type of crank assembly for a human-powered vehicle of the present invention comprises: a crankshaft, a crank arm, and a front sprocket assembly of the first type; the crankshaft is rotatably coupled to the electric auxiliary drive unit; the crank arm is rotatable with the crankshaft and coupled to the crankshaft in a torque transmission state.

The crank assembly of the 20th type can improve the chain holding force of a human-powered vehicle with an electric auxiliary drive unit. In addition, in a human-powered vehicle with an electric auxiliary drive unit, the reduction in driving efficiency can be suppressed by properly maintaining the chain path. Therefore, the wear of the chain and sprocket can be suppressed.

The front sprocket assembly for a human-powered vehicle and the crank assembly for a human-powered vehicle of the present invention can be applied to a human-powered vehicle with an electric auxiliary drive unit and have excellent chain retention force.

AC1: 1st common axis

AC2: Second common axis

AC3: The third common axis

AC4: 4th common axis

AF1: 1st fastening axis

AF2: Second fastening axis

AF3: 3rd fastening axis

AF4: 4th fastening axis

AF5: Fifth fastening axis

AF6: 6th fastening axis

AF7: 7th fastening axis

AF8: 8th fastening axis

AG1: 1st connection angle

AG2: Second connection angle

AG3: 3rd connection angle

AG4: 4th connection angle

AGS1: 1st sliding angle

AGS2: 2nd sliding angle

AGS3: 3rd sliding angle

AGS4: 4th sliding angle

CA: Center of rotation axis

CS: axial center plane

DA: Axial direction

DC: Circumferential direction

LR1: Reference line 1

LR2: 2nd reference line

LR3: 3rd reference line

LR4: 4th reference line

LRS1: 1st radial length

LRS2: 2nd radial length

PA1: 1st axis direction surface

PA2: 2nd axis direction surface

PRS1: 1st sliding reference line

PRS2: 2nd sliding reference line

PRS3: 3rd sliding reference line

PRS4: 4th sliding reference line

PS1: 1st sliding center point

PS2: Second sliding center point

PS3: 3rd sliding center point

PS4: 4th sliding center point

WA1: The first maximum chain engagement axis width

WA2: The second largest chain engagement axis width

WAI: Interval of inner connecting rod in axial direction

WAJ: External connecting rod axial spacing

10: Human-powered vehicle

14: Crank arm

18: Crankshaft

20: Electric auxiliary drive unit

28: Output shaft

28A: Sprocket assembly engagement part

28B: Female thread part

30: Front sprocket assembly

32:Front sprocket

34: Sprocket gear shifting mechanism

36: Chain wheel body

38: Sprocket gear

40: Sprocket carrier

42: Base components

42A: Driving unit engagement part

44: Locking components

46: Cylindrical main body

46A: Male thread part

48: protrusion

50: Sliding part

50A: 1st sliding part

50B: 2nd sliding part

50C: 3rd sliding part

50D: 4th sliding part

60A: 1st connection part

60B: Second connection part

60C: 3rd connection

60D: 4th connection

60E: 5th connection

60F: 6th connection

60G: 7th connection

60H: 8th connection

62A: First fastening member

62B: Second fastening member

62C: The third fastening member

62D: 4th fastening member

72: 1st tooth

72A: The outermost tooth end in the first radial direction

74: 2nd tooth

74A: The outermost tooth end in the second radial direction

80:Chain

82: Inner chain link

84:External chain

90: Crank assembly

[Figure 1] is a schematic diagram showing a portion of a human-powered vehicle of the embodiment viewed from above.

[Figure 2] is a three-dimensional diagram of the crank assembly and electric auxiliary drive unit of the human-powered vehicle in Figure 1.

[Figure 3] is a bottom view of the crank assembly and electric auxiliary drive unit in Figure 2.

[Figure 4] is a side view of the front sprocket assembly included in the crank assembly of Figure 3.

[Figure 5] is an exploded perspective view of the crank assembly in Figure 3.

[Figure 6] is a cross-sectional view of the crank assembly in Figure 3.

[Figure 7] is an exploded perspective view of the front sprocket assembly in Figure 4.

[Figure 8] is an exploded perspective view of the sliding body and retaining member in Figure 7.

[Figure 9] is a side view of the front sprocket in Figure 7.

[Figure 10] is a side view of the sprocket carrier in Figure 7.

[Figure 11] is a side view of the assembly of the front sprocket, sprocket carrier and crank arm in Figure 5.

[Figure 12] is a side view of the assembly of the front sprocket, sprocket gear shifting mechanism and crank arm in Figure 5.

[Figure 13] is a top view of the first tooth of the front sprocket in Figure 9.

[Figure 14] is a top view of the second tooth of the front sprocket in Figure 9.

[Figure 15] is a schematic diagram showing the relative arrangement of the first and second teeth of the chain of a human-powered vehicle.

[Figure 16] is a partial enlarged view of the front sprocket in Figure 9.

[Figure 17] is a side view of the first tooth in Figure 9.

[Figure 18] is a side view of the second tooth in Figure 9.

[Figure 19] is a schematic diagram of the front sprocket assembly in Figure 1.

[Figure 20] is a schematic diagram of a front sprocket assembly of a modified example.

<First implementation method>

The front sprocket assembly 30 for a human-powered vehicle according to an embodiment will be described with reference to FIGS. 1 to 8 . The human-powered vehicle 10 has at least one wheel and is a vehicle that can be driven at least by human power. The human-powered vehicle 10 includes, for example, various types of bicycles such as mountain bikes, road bikes, city bikes, cargo bikes, hand-cranked bikes, and recumbent bikes. The number of wheels that the human-powered vehicle 10 has is not limited. The human-powered vehicle 10 also includes, for example, a unicycle and a vehicle with more than three wheels. The human-powered vehicle 10 is not limited to a vehicle that is driven only by human power. The human-powered vehicle 10 includes: an electric bicycle (E-bike) that is propelled not only by human power but also by the power of an electric motor. The electric bicycle includes an electric-assisted bicycle that is propelled by an electric motor. In the following implementation, the human-powered vehicle 10 is described as an electric-assisted bicycle (E-bike).

As shown in FIG. 1 , the human-powered vehicle 10 includes: a frame 12 for supporting two wheels, a crank arm 14, a plurality of rear sprockets 16, a crank shaft 18, an electric auxiliary drive unit 20, a crank assembly 90, and a chain 80.

The crank assembly 90 for a human-powered vehicle includes: a crankshaft 18, a crank arm 14, and a front sprocket assembly 30. The crankshaft 18 is rotatably coupled to the electric auxiliary drive unit 20. The crank arm 14 can rotate integrally with the crankshaft 18 and is coupled to the crankshaft 18 in a torque transmission state.

The electric auxiliary drive unit 20 is mounted on the frame 12. As shown in Figures 1 to 3, the electric auxiliary drive unit 20 has: a housing 22, a motor 24, a speed reducer 26, and an output shaft 28. The motor 24 and the speed reducer 26 are accommodated in the housing 22. The crankshaft 18 extends through the housing 22 and can rotate relative to the housing 22. The crank arms 14 are respectively mounted on both ends of the crankshaft 18 protruding from the housing 22 in the axial direction. The output shaft 28 is arranged in the housing 22 and is located around the crankshaft 18. The output shaft 28 is arranged in the housing 22 and is coaxial with the crankshaft 18. The electric auxiliary drive unit 20 may also be provided with a crankshaft 18.

In one example, the motor 24 transmits the torque to the output shaft 28 via the speed reducer 26. In one example, the motor 24 transmits the torque generated by the rotation of the motor 24 to the output shaft 28 via a transmission element such as a one-way clutch. In one example, the crankshaft 18 transmits the torque generated by the rotation of the crank arm 14 to the output shaft 28 via a transmission element such as a one-way clutch. The output shaft 28 transmits the torque to the front sprocket assembly 30.

As shown in Figures 4 to 6, the front sprocket assembly 30 for a human-powered vehicle includes: a front sprocket 32 and a sprocket gear shifting mechanism 34.

The front sprocket 32 includes a sprocket body 36 and a plurality of sprocket teeth 38. The plurality of sprocket teeth 38 are arranged on the outer periphery of the sprocket body 36 in the circumferential direction DC relative to the rotation center axis CA of the front sprocket 32.

The sprocket gear shifting mechanism 34 includes a sprocket carrier 40, which is coupled to the sprocket body 36 of the front sprocket 32 in a torque transmission state. The sprocket gear shifting mechanism 34 includes a base member 42, which is detachably coupled to the electric auxiliary drive unit 20 for a human-powered vehicle in a torque transmission state.

In the assembled state of the front sprocket assembly 30 and the electric auxiliary drive unit 20, the sprocket carrier 40 can move relative to the base member 42, and the plurality of sprocket teeth 38 of the front sprocket 32 can be displaced relative to the electric auxiliary drive unit 20 at least in the axial direction DA of the front sprocket 32 relative to the rotation center axis CA.

In this embodiment, the rotation center axis of the base member 42 is consistent with the rotation center axis CA of the front sprocket 32. It can also be said that the plurality of sprocket teeth 38 of the front sprocket 32 can be displaced relative to the electric auxiliary drive unit 20 at least in the axial direction relative to the rotation center axis of the base member 42.

As shown in FIG. 1 , the chain 80 is hung around: the front sprocket 32 and a rear sprocket 16 selected from a plurality of rear sprockets 16.

As shown in FIG. 6 , the electric auxiliary drive unit 20 further has a sprocket assembly engaging portion 28A. In the present embodiment, the sprocket assembly engaging portion 28A is disposed on the output shaft 28.

For example, the base member 42 of the sprocket gear shifting mechanism 34 has a drive unit engaging portion 42A, and the drive unit engaging portion 42A is detachably engaged with the sprocket assembly engaging portion 28A of the electric auxiliary drive unit 20 in the state of torque transmission.

For example, the drive unit engagement portion 42A of the base member 42 can be removably engaged with the sprocket assembly engagement portion 28A provided on the output shaft 28 of the electric auxiliary drive unit 20 in the state of torque transmission. Thus, the base member 42 of the sprocket gear shifting mechanism 34 is indirectly coupled to the crank axle 18 and the crank arm 14 via the output shaft 28 during pedaling and in the state of torque transmission.

For example, the drive unit engagement portion 42A is a cylindrical body and is located around the sprocket assembly engagement portion 28A provided at the front end of the output shaft 28. In this embodiment, the drive unit engagement portion 42A and the sprocket assembly engagement portion 28A are engaged by spline engagement so that they can move relative to each other in the axial direction DA relative to the rotation center axis CA of the front sprocket 32 and can transmit torque in the circumferential direction DC.

As shown in FIG. 6 and FIG. 7, the front sprocket assembly 30 further has a locking member 44. The locking member 44, in the assembled state, fixes the base member 42 to the output shaft 28 of the electric auxiliary drive unit 20 to limit the movement of the base member 42 in the axial direction DA relative to the rotation center axis CA.

In one example, the locking member 44 includes: a cylindrical main body 46 having a central axis, and a protrusion 48 extending radially outward from the cylindrical main body 46 relative to the central axis of the cylindrical main body 46. The cylindrical main body 46 has a male threaded portion 46A. The male threaded portion 46A is used to engage with a female threaded portion 28B provided on the output shaft 28 of the electric auxiliary drive unit 20. The protrusion 48 abuts against the base member 42 in the assembled state. The central axis of the cylindrical main body 46 coincides with the rotational central axis CA of the front sprocket 32. The female threaded portion 28B is formed on the inner circumferential surface of the cylindrical front end portion of the output shaft 28. When the base member 42 is engaged with the output shaft 28, the locking member 44 is screwed into the output shaft 28 through the internal space of the base member 42, so that the protrusion 48 abuts against the base member 42 in the axial direction.

As shown in Figures 5 to 8 and 12, the sprocket gear shifting mechanism 34 has four sliding parts 50, namely, a first sliding part 50A, a second sliding part 50B, a third sliding part 50C, and a fourth sliding part 50D. Each sliding part 50 includes a first sliding member 52, a second sliding member 54, and a sliding body 56.

The first sliding member 52 is provided on the sprocket carrier 40. Specifically, four first sliding members 52 are arranged at equal angular intervals in the circumferential direction on the inner peripheral surface of the sprocket carrier 40 having a substantially circular cross-sectional shape. The first sliding member 52 has a groove extending in the axial direction DA relative to the rotation center axis CA.

The second sliding member 54 is provided on the base member 42. Specifically, the base member 42 has a four-corner frame-shaped portion, and four second sliding members 54 are arranged at equal angles in the circumferential direction on the outer surface of the four-corner frame-shaped portion. The second sliding member 54 is located near the corners of the four-corner frame-shaped portion of the base member 42. The second sliding member 54 has a groove extending in the axial direction DA relative to the rotation center axis CA. The sprocket carrier 40 is arranged around the four-corner frame-shaped portion of the base member 42.

A square frame-shaped retaining member 58 is arranged between the sprocket carrier 40 and the base member 42. The retaining member 58 has a retaining hole 58A for retaining the sliding body 56. Two retaining holes 58A for retaining two sliding bodies 56 are respectively provided near the four corners of the retaining member 58.

In each sliding part 50, two sliding bodies 56 are held by the holding hole 58A of the holding member 58 so as to be located between the first sliding member 52 and the second sliding member 54. The first sliding member 52 and the second sliding member 54 slide with the sliding body 56 respectively. In this way, the sprocket carrier 40 together with the front sprocket 32 can move relative to the base member 42 in the axial direction DA relative to the rotation center axis CA. For example, as shown in FIG. 6, the front sprocket 32 located at the position shown by the solid line can be moved to the position shown by the two-point chain line.

As shown in Figures 7 and 12, the base member 42 has at least one limiting piece 42B. In this embodiment, four limiting pieces 42B protrude radially outward from the outer surface of the four corner frame-shaped parts of the base member 42 and are arranged at equal angles in the circumferential direction. The sprocket carrier 40 has at least one abutment piece 40A. In this embodiment, four abutment pieces 42A protrude radially inward from the inner circumferential surface of the sprocket carrier 40 and are arranged at equal angles in the circumferential direction. By allowing the four abutment pieces 40A to abut against the corresponding limiting pieces 42B, the movement of the sprocket carrier 40 in the axial direction DA relative to the base member 42 is limited.

The sliding body 56 is engaged with the groove of the first sliding member 52 and the groove of the second sliding member 54. The square frame-shaped retaining member 58 is fitted into the square frame-shaped portion of the base member 42 from the outside. The sprocket carrier 40 can be engaged with the portion near the corner portion of the retaining member 58 in the circumferential direction at the portion having the first sliding member 52. Therefore, the relative rotation of the base member 42 and the sprocket carrier 40 is restricted.

In this embodiment, the sliding body 56 is, for example, a rolling body formed by a steel ball. The sliding body 56 may also be a needle-shaped rolling body.

The sliding part 50 can also be formed by a sliding bearing. In this case, the sliding body 56 is omitted, and at least one first sliding member provided on the sprocket carrier 40 and at least one second sliding member provided on the base member 42 are allowed to slide directly with each other.

As shown in FIGS. 2 to 6 , the front sprocket assembly 30 further includes an annular outer casing 92 and a retaining collar 98. The outer casing 92 includes a first outer casing portion 94 and a second outer casing portion 96. The outer casing 92 isolates the annular space between the base member 42 and the sprocket carrier 40 from the external space and protects the sliding portion 50 provided between the base member 42 and the sprocket carrier 40 from the external environment. The first outer casing portion 94 includes an inner peripheral end portion 94A engaged with the inner peripheral surface of the four-corner frame-shaped portion of the base member 42 and an outer peripheral end portion 94B engaged with the outer peripheral surface of the sprocket carrier 40. The second outer shell 96 is provided on the opposite side of the first outer shell 94 with the sprocket carrier 40 interposed therebetween. The second outer shell 96 has an inner peripheral end 96A engaged with the outer peripheral surface of the base member 42 and an outer peripheral end 96B mounted and engaged with the outer peripheral surface of the sprocket carrier 40. The outer peripheral end 94B of the first outer shell 94 and the outer peripheral end 96B of the second outer shell 96 are connected to each other. The retaining collar 98 is disposed around the outer peripheral end 96B of the second outer shell 96 and fixes the outer peripheral end 96B of the second outer shell 96 to the sprocket carrier 40. The first outer shell 94 and the second outer shell 96 are preferably flexible. Thereby, the first outer shell portion 94 and the second outer shell portion 96 can be deformed to allow the sprocket carrier 40 to move in the axial direction relative to the base member 42.

As shown in FIG. 7 and FIG. 9 to FIG. 12, the sprocket body 36 includes: a first connection portion 60A having a first fastening axis AF1, a second connection portion 60B having a second fastening axis AF2, a third connection portion 60C having a third fastening axis AF3, and a fourth connection portion 60D having a fourth fastening axis AF4. The second connection portion 60B is arranged in a circumferential direction DC relative to the rotation center axis CA of the front sprocket 32 so as to be separated from the first connection portion 60A without other connection portions 60C and 60D therebetween. The third connection portion 60C is arranged in a circumferential direction DC so as to be separated from the second connection portion 60B without other connection portions 60A and 60D therebetween. The fourth connecting portion 60D is arranged in the circumferential direction DC so as to be separated from the first connecting portion 60A and the third connecting portion 60C respectively and without any other connecting portion 60B therebetween.

The sprocket carrier 40 includes a fifth connection portion 60E having a fifth fastening axis AF5, a sixth connection portion 60F having a sixth fastening axis AF6, a seventh connection portion 60G having a seventh fastening axis AF7, and an eighth connection portion 60H having an eighth fastening axis AF8. The sixth connection portion 60F is arranged in the circumferential direction DC away from the fifth connection portion 60E without any other connection portions 60G and 60H therebetween. The seventh connection portion 60G is arranged in the circumferential direction DC away from the sixth connection portion 60F without any other connection portions 60E and 60H therebetween. The eighth connection portion 60H is arranged in the circumferential direction DC away from the fifth connection portion 60E and the seventh connection portion 60G without any other connection portions 60F therebetween.

The first fastening axis AF1 of the first connecting portion 60A and the fifth fastening axis AF5 of the fifth connecting portion 60E are made to be aligned with each other relative to the first common axis AC1, so that the first fastening member 62A passes through at least one of the first connecting portion 60A and the fifth connecting portion 60E. The second fastening axis AF2 of the second connecting portion 60B and the sixth fastening axis AF6 of the sixth connecting portion 60F are made to be aligned with each other relative to the second common axis AC2, so that the second fastening member 62B passes through at least one of the second connecting portion 60B and the sixth connecting portion 60F. The third fastening axis AF3 of the third connecting part 60C and the seventh fastening axis AF7 of the seventh connecting part 60G are aligned with each other relative to the third common axis AC3, so that the third fastening member 62C passes through at least one of the third connecting part 60C and the seventh connecting part 60G. The fourth fastening axis AF4 of the fourth connecting part 60D and the eighth fastening axis AF8 of the eighth connecting part 60H are aligned with each other relative to the fourth common axis AC4, so that the fourth fastening member 62D passes through at least one of the fourth connecting part 60D and the eighth connecting part 60H.

The first connection angle AG1 is defined as the angle between the first reference line LR1 extending from the rotation center axis CA toward the first common axis AC1 in the circumferential direction DC and the second reference line LR2 extending from the rotation center axis CA toward the second common axis AC2, so that the other common axes AC3 and AC4 are not located between the first common axis AC1 and the second common axis AC2 in the circumferential direction DC. The second connection angle AG2 is defined as the angle between the second reference line LR2 in the circumferential direction DC and the third reference line LR3 extending from the rotation center axis CA toward the third common axis AC3, so that the other common axes AC1 and AC4 are not located between the second common axis AC2 and the third common axis AC3 in the circumferential direction DC. The third connection angle AG3 is defined as the angle between the third reference line LR3 in the circumferential direction DC and the fourth reference line LR4 extending from the rotation center axis CA toward the fourth common axis AC4, so that the other common axes AC1 and AC2 are not located between the third common axis AC3 and the fourth common axis AC4 in the circumferential direction DC. The fourth connection angle AG4 is defined as the angle between the fourth reference line LR4 in the circumferential direction DC and the first reference line LR1, so that the other common axes AC2 and AC3 are not located between the fourth common axis AC4 and the first common axis AC1 in the circumferential direction DC. The first connection angle AG1, the second connection angle AG2, the third connection angle AG3, and the fourth connection angle AG4 are equal to each other.

In this embodiment, the first connecting portion 60A, the second connecting portion 60B, the third connecting portion 60C, and the fourth connecting portion 60D include a hole portion formed in: a connecting body protruding radially inward from the annular sprocket body 36.

In this embodiment, the fifth connecting portion 60E, the sixth connecting portion 60F, the seventh connecting portion 60G, and the eighth connecting portion 60H include a hole portion formed in: a connecting body protruding radially outward from the annular sprocket body 40.

In this embodiment, the first fastening member 62A, the second fastening member 62B, the third fastening member 62C, and the fourth fastening member 62D are respectively connected through: a corresponding connection part among the first connection part 60A, the second connection part 60B, the third connection part 60C, and the fourth connection part 60D, and a corresponding connection part among the fifth connection part 60E, the sixth connection part 60E, the seventh connection part 60G, and the eighth connection part 60H. The first fastening member 62A, the second fastening member 62B, the third fastening member 62C, and the fourth fastening member 62D are used to fix the front sprocket 32 to the sprocket carrier 40.

As shown in FIG. 1 and FIG. 3, the front sprocket 32 has a first axial surface PA1 and a second axial surface PA2 on the opposite side of the first axial surface PA1 in the axial direction DA. When the front sprocket assembly 30 is mounted on the human-powered vehicle 10, the second axial surface PA2 is opposite to the axial center surface CS of the human-powered vehicle 10 relative to the rotation center axis CA.

As shown in FIG. 11, when viewed from the first axial plane PA1 toward the second axial plane PA2 in the axial direction DA, the first common axis AC1 to the fourth common axis AC4 are arranged in the order of the first common axis AC1 to the fourth common axis AC4 in the circumferential direction DC from the crank arm 14 in the counterclockwise direction. In FIG. 11, the base member 42 and the first outer shell 94 are omitted for easy viewing of the sprocket carrier 40.

As shown in FIG. 12, the sprocket gear shifting mechanism 34 includes: a first sliding portion 50A having a first sliding center point PS1, a second sliding portion 50B having a second sliding center point PS2, a third sliding portion 50C having a third sliding center point PS3, and a fourth sliding portion 50D having a fourth sliding center point PS4. The first housing portion 94 is omitted in FIG. 12. In FIG. 12, the first to fourth sliding center points PS1, PS2, PS3, and PS4 are located at the center of the sliding body 56.

The second sliding portion 50B is arranged in the circumferential direction DC relative to the rotation center axis CA of the front sprocket 32 so as to be separated from the first sliding portion 50A and there is no other sliding portion 50C or 50D therebetween. The third sliding portion 50C is arranged in the circumferential direction DC so as to be separated from the second sliding portion 50B and there is no other sliding portion 50A or 50D therebetween. The fourth sliding portion 50D is arranged in the circumferential direction DC so as to be separated from the first sliding portion 50A and the third sliding portion 50C and there is no other sliding portion 50B therebetween.

The first sliding angle AGS1 is defined as the angle between the first sliding reference line PRS1 extending from the rotation center axis CA toward the first sliding center point PS1 in the circumferential direction DC and the second sliding reference line PRS2 extending from the rotation center axis CA toward the second sliding center point PS2, so that the other sliding center points PS3 and PS4 are not located between the first sliding center point PS1 and the second sliding center point PS2 in the circumferential direction DC. The second sliding angle AGS2 is defined as the angle between the second sliding reference line PRS2 and the third sliding reference line PRS3 extending from the rotation center axis CA toward the third sliding center point PS3 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 third sliding angle AGS3 is defined as the angle between the third sliding reference line PRS3 in the circumferential direction DC and the fourth sliding reference line PRS4 extending from the rotation center axis CA toward the fourth sliding center point PS4, 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 fourth sliding angle AGS4 is defined as the angle between the fourth sliding reference line PRS4 and the first sliding reference line PRS1 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 first sliding angle AGS1, the second sliding angle AGS2, the third sliding angle AGS3, and the fourth sliding angle AGS4 are equal to each other.

In the assembled state, the first sliding portion 50A is arranged on the upstream side of the driving rotation direction DR of the front sprocket 32 relative to the first fastening member 62A. In the assembled state, the second sliding portion 50B is arranged on the upstream side of the driving rotation direction DR of the front sprocket 32 relative to the second fastening member 62B. In the assembled state, the third sliding portion 50C is arranged on the upstream side of the driving rotation direction DR of the front sprocket 32 relative to the third fastening member 62C. In the assembled state, the fourth sliding portion 50D is arranged on the upstream side of the driving rotation direction DR of the front sprocket 32 relative to the fourth fastening member 62D.

In the assembled state and viewed from the radial direction relative to the rotation center axis CA, the first sliding portion 50A partially overlaps with the first fastening member 62A in the circumferential direction DC. In the assembled state and viewed from the radial direction, the second sliding portion 50B partially overlaps with the second fastening member 62B in the circumferential direction DC. In the assembled state and viewed from the radial direction, the third sliding portion 50C partially overlaps with the third fastening member 62C in the circumferential direction DC. In the assembled state and viewed from the radial direction, the fourth sliding portion 50D partially overlaps with the fourth fastening member 62D in the circumferential direction DC.

When viewed from the first axial plane PA1 toward the second axial plane PA2 in the axial direction DA, the first sliding center point PS1 to the fourth sliding center point PS4 are arranged in the order of the first sliding center point PS1 to the fourth sliding center point PS4 in the counterclockwise direction from the crank arm 14 in the circumferential direction DC.

When viewed from the first axial plane PA1 toward the second axial plane PA2 in the axial direction DA, the fourth sliding center point PS4 at least partially overlaps with the crank arm 14.

Referring to Figures 13 to 18, the chain gear 38 and the chain 80 are described. As shown in Figures 15 and 16, the plurality of chain gear teeth 38 include: at least one first tooth 72 and at least one second tooth 74. At least one first tooth 72 has a first maximum chain engagement axial width WA1 in the axial direction DA relative to the rotation center axis CA. At least one second tooth 74 has a second maximum chain engagement axial width WA2 in the axial direction DA relative to the rotation center axis CA. In the axial direction DA of the rotation center axis CA, the first maximum chain engagement axial width WA1 is greater than the second maximum chain engagement axial width WA2.

The chain 80 has an inner chain piece 82 and an outer chain piece 84. The pair of inner chain pieces 82 arranged at intervals and the pair of outer chain pieces 84 arranged at intervals are alternately arranged and connected to each other.

The first maximum chain engagement axial width WA1 is greater than: the inner chain axial spacing WAI defined between a pair of inner chain plates 82 of the human-driven vehicle chain 80 in the axial direction DA, and less than: the outer chain axial spacing WAJ defined between a pair of outer chain plates 84 of the human-driven vehicle chain 80 in the axial direction DA. The second maximum chain engagement axial width WA2 is less than the inner chain axial spacing WAI. The first maximum chain engagement axial width WA1 of at least one first tooth 72 is more than 75% of the outer chain axial spacing WAJ.

The first radial length LRS1 is defined as the length between the first radial outermost tooth end 72A of at least one first tooth 72 in the radial direction relative to the rotation center axis CA and the rotation center axis CA. The second radial length LRS2 is defined as the length between the second radial outermost tooth end 74A of at least one second tooth 74 in the radial direction relative to the rotation center axis CA and the rotation center axis CA. The first radial length LRS1 is longer than the second radial length LRS2. The second radial length LRS2 is in the range of 75% to 95% of the first radial length LRS1.

At least one first tooth 72 includes a plurality of first teeth 72; at least one second tooth 74 includes a plurality of second teeth 74. The plurality of first teeth 72 and the plurality of second teeth 74 are alternately arranged in the circumferential direction DC.

As shown in FIG. 13, at least one first tooth 72 has: a first axial tooth end center line LCRT1 offset from a first axial tooth bottom center plane CST1 of at least one first tooth 72 in the axial direction DA. At least one first tooth 72 is asymmetric relative to the first axial tooth bottom center plane CST1 in the axial direction DA.

As shown in FIG. 14, at least one second tooth 74 has: a second axial tooth end center line LCRT2 offset from a second axial tooth bottom center plane CST2 of at least one second tooth 74 in the axial direction DA. At least one second tooth 74 is asymmetric relative to the second axial tooth bottom center plane CST2 in the axial direction DA.

As shown in FIG. 17, at least one first tooth 72 is asymmetric relative to the first circumferential tooth bottom center line LCT1 in the circumferential direction DC. Specifically, the driving surface of the first tooth 72 may be different from the non-driving surface of the first tooth 72 in at least one of size and shape. The driving surface is the surface on the downstream side of the driving rotation direction DR of the first tooth 72. The non-driving surface is the surface on the upstream side of the driving rotation direction DR of the first tooth 72. In this embodiment, the chamfer of the driving surface side of the first tooth 72 is greater than the chamfer of the non-driving surface of the first tooth 72. In other examples, the curvature of the driving surface of the first tooth 72 may be different from the curvature of the non-driving surface.

As shown in FIG. 18, at least one second tooth 74 is asymmetric in the circumferential direction DC relative to the center line LCT2 of the second circumferential tooth bottom. Specifically, the driving surface of the second tooth 74 may be different from the non-driving surface of the second tooth 74 in at least one of its size and shape. The driving surface is the surface on the downstream side of the driving rotation direction DR of the second tooth 74. The non-driving surface is the surface on the upstream side of the driving rotation direction DR of the second tooth 74. In this embodiment, a notch is formed on the driving surface at the tooth end of the second tooth 74, and no notch is formed on the non-driving surface. In other examples, the curvature of the driving surface of the second tooth 74 may be different from the curvature of the non-driving surface.

The function of the front sprocket assembly 30 of this embodiment is described.

As shown in FIG. 19, in the front sprocket assembly 30 of the present embodiment, a force is applied to the front sprocket 32 in the axial direction DA relative to the rotation center axis CA in response to the movement of the chain 80 between the plurality of rear sprockets 16. The sprocket carrier 40 is moved in the axial direction DA relative to the rotation center axis CA relative to the base member 42 by the force. In this way, the front sprocket 32 coupled to the sprocket carrier 40 can be displaced in the axial direction DA relative to the rotation center axis CA relative to the electric auxiliary drive unit 20.

At least one first tooth 72 has: a first axial tooth end center line LCRT1 offset from the first axial tooth bottom center plane CST1 in the axial direction DA. At least one first tooth 72 is asymmetric relative to the first axial tooth bottom center plane CST1 in the axial direction DA. Therefore, even if the chain 80 is tilted in the axial direction DA between the front sprocket 32 and the plurality of rear sprockets 16, the chain holding force of the front sprocket 32 can be improved.

At least one second tooth 74 has: a second axial tooth end center line LCRT2 offset from the second axial tooth bottom center plane CST2 in the axial direction DA. At least one second tooth 74 is asymmetric relative to the second axial tooth bottom center plane CST2 in the axial direction DA. Therefore, even if the chain 80 is tilted in the axial direction DA between the front sprocket 32 and the plurality of rear sprockets 16, the chain holding force of the front sprocket 32 can be improved.

<Variation example>

The description of the implementation method is an example of the form taken by the front sprocket assembly and crank assembly for human-powered vehicle of the present invention, and is not intended to limit its form. The front sprocket assembly and crank assembly for human-powered vehicle of the present invention can take the form of a modified example of the implementation method shown below and a combination of at least two non-contradictory modified examples. In the following modified examples, the same symbols as the implementation method are added to the parts common to the implementation method, and their description is omitted.

As shown in Figures 5 and 6, in this embodiment, the crankshaft 18 and the output shaft 28 are coaxial, but they may not be coaxial.

The first connecting portion 60A, the second connecting portion 60B, the third connecting portion 60C, and the fourth connecting portion 60D of the sprocket body 36 may also be arranged at unequal intervals in the circumferential direction DC.

The fifth connecting portion 60E, the sixth connecting portion 60F, the seventh connecting portion 60G, and the eighth connecting portion 60H of the sprocket carrier 40 may also be arranged without equal intervals in the circumferential direction DC.

The sprocket body 36 and the sprocket carrier 40 only need to include at least one connecting portion.

The first sliding portion 50A, the second sliding portion 50B, the third sliding portion 50C, and the fourth sliding portion 50D may also be arranged at unequal intervals in the circumferential direction DC.

When viewed from the radial direction relative to the rotation center axis CA, the first sliding portion 50A, the second sliding portion 50B, the third sliding portion 50C, and the fourth sliding portion 50D may not overlap with the corresponding fastening members among the first fastening member 62A, the second fastening member 62B, the third fastening member 62C, and the fourth fastening member 62D in the circumferential direction DC.

The sprocket gear shifting mechanism 34 only needs to have at least one sliding portion 50.

As shown in FIG. 20, the sprocket gear shifting mechanism 34 of the front sprocket assembly 30 may also include: a sprocket carrier 40 that can swing around the axis CZ in the vertical direction of the human-powered vehicle 10 relative to the base member 42. In response to the movement of the chain 80 between the plurality of rear sprockets 16, the sprocket carrier 40 together with the front sprocket 32 swings around the axis CZ and tilts relative to the base member 42. Thereby, the plurality of sprocket teeth 38 of the front sprocket 32 can be shifted relative to the electric auxiliary drive unit 20 in at least the axial direction DA of the front sprocket 32 relative to the rotation center axis CA. The so-called "displacement in the axial direction DA of at least the front sprocket 32 relative to the rotation center axis CA" means that the front sprocket 32 is displaced in the axial direction DA relative to the rotation center axis CA in a state where the axial line relative to the crankshaft 18 is not tilted. In this way, the front sprocket 32 is displaced relative to the electric auxiliary drive unit 20 in response to the movement of the chain 80, so that the chain holding force of the human-powered vehicle 10 equipped with the electric auxiliary drive unit 20 is improved. In addition, in the human-powered vehicle 10 equipped with the electric auxiliary drive unit 20, by appropriately maintaining the chain path, the drive efficiency can be suppressed from being reduced, and the wear of the chain 80 and the sprocket can be suppressed.

The motor 24 can also be configured to transmit torque to the crankshaft 18. In this case, the output shaft 28 can be omitted, and the drive unit engaging portion 42A of the base member 42 can be detachably engaged with the sprocket assembly engaging portion provided on the crankshaft 18 in the state of torque transmission.

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

14: Crank arm

20: Electric auxiliary drive unit

22: Shell

32:Front sprocket

36: Chain wheel body

38: Sprocket gear

40: Sprocket carrier

62C: The third fastening member

62D: 4th fastening member

90: Crank assembly

92: Shell

98:Retaining ring

Claims (20)

A front sprocket assembly for a human-powered vehicle comprises: a front sprocket and a sprocket gear shifting mechanism; the front sprocket comprises: a sprocket body, and a plurality of sprocket gears arranged on the outer periphery of the sprocket body in a circumferential direction relative to a rotation center axis of the front sprocket; the sprocket gear shifting mechanism comprises: a sprocket carrier coupled to the sprocket body of the front sprocket in a torque transmission state, and a sprocket gear shifting mechanism coupled to the sprocket body of the front sprocket in a torque transmission state. A base member that can be detachably coupled to an electric auxiliary drive unit for a human-powered vehicle in a removable state; in the assembled state of the front sprocket assembly and the electric auxiliary drive unit, the sprocket carrier can move relative to the base member, and the plurality of sprocket teeth of the front sprocket can be displaced relative to the electric auxiliary drive unit at least in the axial direction of the front sprocket relative to the rotation center axis. As in claim 1, the front sprocket assembly for a human-powered vehicle, wherein the base component of the sprocket gear shifting mechanism has a drive unit engaging portion, and the drive unit engaging portion can be detachably engaged with the sprocket assembly engaging portion of the electric auxiliary drive unit in a torque transmission state. A front sprocket assembly for a human-powered vehicle comprises: a front sprocket and a sprocket gear shifting mechanism; the front sprocket comprises: a sprocket body, and a plurality of sprocket teeth arranged on the outer periphery of the sprocket body in a circumferential direction relative to a rotation center axis of the front sprocket; the sprocket gear shifting mechanism comprises: a sprocket body that is arranged to move relative to the front sprocket body in a torque transmission state; The invention relates to a sprocket carrier combined with the sprocket body of the front sprocket wheel, and a base member that can be detachably combined with the electric auxiliary drive unit for the human-powered vehicle in the state of torque transmission; in the assembled state of the front sprocket assembly and the electric auxiliary drive unit, the sprocket carrier can move relative to the base member, and the plurality of sprocket teeth of the front sprocket are relatively close to each other. The electric auxiliary drive unit can at least be displaced in the axial direction of the front sprocket relative to the rotation center axis; the base component of the sprocket gear shifting mechanism has a drive unit engaging portion, and the drive unit engaging portion can be detachably engaged with the sprocket assembly engaging portion of the electric auxiliary drive unit in a torque transmission state; The drive unit engagement portion of the base component can be detachably engaged with the sprocket assembly engagement portion provided on the output shaft of the electric auxiliary drive unit in the state of torque transmission; thereby, the base component of the sprocket gear shifting mechanism is indirectly coupled to the crankshaft and crank arm in the state of transmitting torque via the output shaft during pedaling. The front sprocket assembly for a human-powered vehicle as claimed in claim 1 or 3 further comprises a locking member, wherein the locking member, in the assembled state, fixes the base member to the output shaft of the electric auxiliary drive unit to limit the axial movement of the base member relative to the rotation center axis. As in claim 4, the front sprocket assembly for a human-powered vehicle, wherein the locking member comprises: a cylindrical main body having a central axis, and a protrusion extending radially outward from the cylindrical main body relative to the central axis of the cylindrical main body; the cylindrical main body has a male threaded portion, and the male threaded portion is used to engage with the female threaded portion of the output shaft provided on the electric auxiliary drive unit; the protrusion abuts against the base member in the assembled state. A front sprocket assembly for a human-powered vehicle as claimed in claim 1 or 3, wherein the sprocket body comprises: a first connecting portion having a first fastening axis, a second connecting portion having a second fastening axis, a third connecting portion having a third fastening axis, and a fourth connecting portion having a fourth fastening axis; the sprocket carrier comprises: a fifth connecting portion having a fifth fastening axis, a sixth connecting portion having a sixth fastening axis, a seventh connecting portion having a seventh fastening axis, and an eighth connection portion having an eighth fastening axis; the second connection portion is arranged in the circumferential direction relative to the rotation center axis of the front sprocket to be separated from the first connection portion and without any other connection portion therebetween; the third connection portion is arranged in the circumferential direction to be separated from the second connection portion and without any other connection portion therebetween; the fourth connection portion is arranged in the circumferential direction to be respectively connected to the first connection portion and the third connection portion The sixth connecting portion is arranged in the circumferential direction to be separated from the fifth connecting portion and to have no other connecting portion therebetween; the seventh connecting portion is arranged in the circumferential direction to be separated from the sixth connecting portion and to have no other connecting portion therebetween; the eighth connecting portion is arranged in the circumferential direction to be separated from the fifth connecting portion and the seventh connecting portion and to have no other connecting portion therebetween; the upper portion of the first connecting portion is arranged The first fastening axis and the fifth fastening axis of the fifth connecting part are aligned with each other relative to the first common axis so that the first fastening member passes through at least one of the first connecting part and the fifth connecting part; the second fastening axis of the second connecting part and the sixth fastening axis of the sixth connecting part are aligned with each other relative to the second common axis so that the second fastening member passes through at least one of the second connecting part and the sixth connecting part. one of them; the third fastening axis of the third connecting part and the seventh fastening axis of the seventh connecting part are aligned with each other relative to the third common axis so that the third fastening member passes through at least one of the third connecting part and the seventh connecting part; the fourth fastening axis of the fourth connecting part and the eighth fastening axis of the eighth connecting part are aligned with each other relative to the fourth common axis so that the fourth fastening member passes through the fourth The first connection angle is defined as the angle between the first reference line extending from the rotation center axis toward the first common axis in the circumferential direction and the second reference line extending from the rotation center axis toward the second common axis, so that the other common axis is not located between the first common axis and the second common axis in the circumferential direction; the second connection angle is defined as the angle between the first reference line extending from the rotation center axis toward the first common axis in the circumferential direction and the second common axis in the circumferential direction. The angle between the second reference line in the circumferential direction and the third reference line extending from the rotation center axis toward the third common axis is used to make the other common axis not located between the second common axis and the third common axis in the circumferential direction; the third connection angle is 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 is used to make the other common axis not located between the second common axis and the third common axis in the circumferential direction. The through axis is not located between the third common axis and the fourth common axis in the circumferential direction; the fourth connection angle is defined as the angle between the fourth reference line and the first reference line in the circumferential direction, which is used to make other common axes not located between the fourth common axis and the first common axis in the circumferential direction; the first connection angle, the second connection angle, the third connection angle, and the fourth connection angle are equal to each other. A front sprocket assembly for a human-powered vehicle as claimed in claim 6, wherein the front sprocket has: a first axial surface, and a second axial surface on the opposite side of the first axial surface in the axial direction; when the front sprocket assembly is mounted on the human-powered vehicle, the second axial surface is opposite to the axial center surface of the human-powered vehicle relative to the rotation center axis; The first to fourth common axes are arranged in the order of the first to fourth common axes in the circumferential direction from the crank arm toward the counterclockwise direction when viewed from the first axial surface toward the second axial surface in the axial direction. A front sprocket assembly for a human-driven vehicle as claimed in claim 6, wherein the sprocket gear shifting mechanism comprises: a first sliding portion having a first sliding center point, a second sliding portion having a second sliding center point, a third sliding portion having a third sliding center point, and a fourth sliding portion having a fourth sliding center point; the second sliding portion is arranged in the circumferential direction relative to the rotation center axis of the front sprocket to be separated from the first sliding portion and without other sliding portions in between; the third sliding portion is arranged in the circumferential direction to be The fourth sliding portion is arranged in the circumferential direction to be separated from the first sliding portion and the third sliding portion, respectively, and there is no other sliding portion therebetween; the first sliding angle 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, so as to ensure that other sliding center points are not located at the first sliding center point in the circumferential direction. 1 sliding center point and the above-mentioned second sliding center point; the second sliding angle is defined as: the angle between the above-mentioned second sliding reference line in the above-mentioned circumferential direction and the third sliding reference line extending from the above-mentioned rotation center axis toward the above-mentioned third sliding center point, which is used to make other sliding center points in the above-mentioned circumferential direction not be located between the above-mentioned second sliding center point and the above-mentioned third sliding center point; the third sliding angle is defined as: the angle between the above-mentioned third sliding reference line in the above-mentioned circumferential direction and the fourth sliding reference line extending from the above-mentioned rotation center axis toward the above-mentioned fourth sliding center point. The angle between the sliding reference lines is used to make other sliding center points not located between the third sliding center point and the fourth sliding center point in the circumferential direction; the fourth sliding angle is defined as: the angle between the fourth sliding reference line and the first sliding reference line in the circumferential direction is used to make other sliding center points not located between the fourth sliding center point and the first sliding center point in the circumferential direction; the first sliding angle, the second sliding angle, the third sliding angle, and the fourth sliding angle are equal to each other. The front sprocket assembly for a human-powered vehicle as claimed in claim 8, wherein the first sliding portion is arranged on the upstream side of the driving rotation direction of the front sprocket relative to the first fastening member in the above-mentioned assembled state, the second sliding portion is arranged on the upstream side of the driving rotation direction of the front sprocket relative to the second fastening member in the above-mentioned assembled state, the third sliding portion is arranged on the upstream side of the driving rotation direction of the front sprocket relative to the third fastening member in the above-mentioned assembled state, and the fourth sliding portion is arranged on the upstream side of the driving rotation direction of the front sprocket relative to the fourth fastening member in the above-mentioned assembled state. A front sprocket assembly for a human-powered vehicle as claimed in claim 8, wherein, in the above-mentioned assembled state and when observed from the radial direction relative to the above-mentioned rotation center axis, the above-mentioned first sliding portion partially overlaps with the above-mentioned first fastening member in the above-mentioned circumferential direction; in the above-mentioned assembled state and when observed from the above-mentioned radial direction, the above-mentioned second sliding portion partially overlaps with the above-mentioned second fastening member in the above-mentioned circumferential direction; in the above-mentioned assembled state and when observed from the above-mentioned radial direction, the above-mentioned third sliding portion partially overlaps with the above-mentioned third fastening member in the above-mentioned circumferential direction; in the above-mentioned assembled state and when observed from the above-mentioned radial direction, the above-mentioned fourth sliding portion partially overlaps with the above-mentioned fourth fastening member in the above-mentioned circumferential direction. A front sprocket assembly for a human-driven vehicle as claimed in claim 1 or 3, wherein the sprocket gear shifting mechanism comprises: a first sliding portion having a first sliding center point, a second sliding portion having a second sliding center point, a third sliding portion having a third sliding center point, and a fourth sliding portion having a fourth sliding center point; the second sliding portion is arranged in the circumferential direction relative to the rotation center axis of the front sprocket to be separated from the first sliding portion and without other sliding portions in between; the third sliding portion is arranged in the circumferential direction The fourth sliding part is arranged in the circumferential direction to be separated from the first sliding part and the third sliding part respectively and there is no other sliding part therebetween; the first sliding angle 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, so as to prevent other sliding center points from being located above the circumferential direction. The first sliding center point is between the first sliding center point and the second sliding center point; the second sliding angle is defined as: the angle between the second sliding reference line in the circumferential direction and the third sliding reference line extending from the rotation center axis toward the third sliding center point, so that other sliding center points are not located between the second sliding center point and the third sliding center point in the circumferential direction; the third sliding angle is defined as: the angle between the third sliding reference line in the circumferential direction and the third sliding reference line extending from the rotation center axis toward the fourth sliding center point. The angle between the 4 sliding reference lines is used to make other sliding center points not located between the 3rd sliding center point and the 4th sliding center point in the circumferential direction; the 4th sliding angle is defined as: the angle between the 4th sliding reference line and the 1st sliding reference line in the circumferential direction is used to make other sliding center points not located between the 4th sliding center point and the 1st sliding center point in the circumferential direction; the 1st sliding angle, the 2nd sliding angle, the 3rd sliding angle, and the 4th sliding angle are equal to each other. A front sprocket assembly for a human-powered vehicle as claimed in claim 11, wherein the front sprocket has: a first axial surface, and a second axial surface on the opposite side of the first axial surface in the axial direction; when the front sprocket assembly is mounted on the human-powered vehicle, the second axial surface is opposite to the axial center surface of the human-powered vehicle relative to the rotation center axis; The first to fourth sliding center points are arranged in the order of the first to fourth sliding center points in the circumferential direction from the crank arm in the counterclockwise direction when viewed from the first axial surface toward the second axial surface in the axial direction. A front sprocket assembly for a human-powered vehicle as claimed in claim 12, wherein, when viewed from the first axial direction surface toward the second axial direction surface in the axial direction, the fourth sliding center point at least partially overlaps with the crank arm. A front sprocket assembly for a human-powered vehicle as claimed in claim 1 or 3, wherein the plurality of sprocket teeth include: at least one first tooth having a first maximum chain engagement axial width in the axial direction relative to the rotation center axis, and at least one second tooth having a second maximum chain engagement axial width in the axial direction relative to the rotation center axis; in the axial direction relative to the rotation center axis, the first maximum chain engagement axial width is greater than the second maximum chain engagement axial width. As in claim 14, the front sprocket assembly for a human-powered vehicle, wherein the first maximum chain engagement axial width is greater than: the inner chain axis direction interval defined between a pair of inner chain plates of the human-powered vehicle chain in the above-mentioned axial direction, and less than: the outer chain axis direction interval defined between a pair of outer chain plates of the human-powered vehicle chain in the above-mentioned axial direction; the second maximum chain engagement axial width is less than the inner chain axis direction interval. As in claim 15, the front sprocket assembly for a human-powered vehicle, wherein the first maximum chain engagement axis direction width of the at least one first tooth is more than 75% of the spacing in the outer chain axis direction. As in claim 14, the front sprocket assembly for a human-powered vehicle, wherein the first radial length is defined as the length between the first radial outermost tooth end of the at least one first tooth and the rotation center axis in the radial direction relative to the rotation center axis; the second radial length is defined as the length between the second radial outermost tooth end of the at least one second tooth and the rotation center axis in the radial direction relative to the rotation center axis; the first radial length is greater than the second radial length. As in claim 17, the front sprocket assembly for a human-powered vehicle, wherein the second radial length is in the range of 75% to 95% of the first radial length. As in claim 14, the front sprocket assembly for a human-powered vehicle, wherein the at least one first tooth includes a plurality of first teeth, the at least one second tooth includes a plurality of second teeth, and the plurality of first teeth and the plurality of second teeth are alternately arranged in the circumferential direction. A crank assembly for a human-powered vehicle, comprising: a crankshaft, a crank arm, and a front sprocket assembly for a human-powered vehicle of claim 1 or 3; the crankshaft is rotatably coupled to an electric auxiliary drive unit; the crank arm is rotatable with the crankshaft and coupled to the crankshaft in a torque transmission state.

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