TW201636261A - Bicycle crank-shaft assembly - Google Patents

Abstract

The invention presents a sprocket component of the crank-shaft assembly for preventing driving efficiency to be lowered. The bicycle crank-shaft assembly 10 comprises a crank component 12, a sprocket component 14, a sliding mechanism 16, and a loose prevention mechanism 22. The crank component 12 has a rotational central axis C. The sliding mechanism 16 is constituted by the connection of the crank component 12 and the sprocket component 14 and can be slide in the direction C and can rotate as a whole. The loose prevention mechanism 22 can prevent the loose of the crank component 12 and the sprocket component 14. The loose prevention mechanism 22 is composed of an elastic component 66.

Description

Bicycle crank assembly

The present invention relates to a crank assembly, particularly a bicycle crank assembly having a central axis of rotation.

In bicycles equipped with a single front sprocket and a plurality of rear sprocket wheels, it has been previously known to shift gears with a rear derailleur. When the shifting operation is performed by the rear derailleur, there is a case where the chain between the front sprocket and the rear sprocket is inclined with respect to the front surface of the front sprocket. If the chain is arranged obliquely between the front sprocket and the rear sprocket, the chain is detached from the front sprocket. Therefore, there has been known a bicycle crank assembly in which the front sprocket is freely moved in the axial direction parallel to the central axis of rotation so that the chain is not easily detached, so that the chain is less likely to be extremely inclined (see, for example, Patent Document 1) .

In the crank assembly of Patent Document 1, at a front end of a plurality of arms provided at one end of a crank arm for mounting a front sprocket, a support shaft extending in an axial direction parallel to a central axis of rotation of the front sprocket is provided. . The sprocket member is movably supported in the axial direction on the support shaft.

Further, Patent Document 1 discloses a crank assembly in which a cylindrical member having a plurality of grooves extending in the circumferential direction and extending in the axial direction is disposed at one end of the crank arm. An end portion of the plurality of sprocket arms radially extending radially inward of the front sprocket is supported by the groove portion of the tubular member in the axial direction.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] US Patent Application Publication No. 2013/0008282

In the crank assembly of Patent Document 1, the front sprocket is supported by the crank arm or the arm extending radially from the front sprocket. Therefore, the strength of the portion supporting the front sprocket is insufficient and the driving efficiency is lowered.

An object of the present invention is to prevent a reduction in driving efficiency in a crank assembly in which a sprocket member can move in a rotation axis direction.

The bicycle crank assembly of the present invention includes a crank member, a sprocket member, a sliding mechanism, and a loosening prevention mechanism. The sprocket member has a central axis of rotation. The slide mechanism couples the sprocket member and the crank member so as to be slidable in the axial direction parallel to the central axis of rotation. The loosening prevention mechanism prevents loosening of the crank member and the sprocket member. The loosening prevention mechanism includes an elastic member.

In the bicycle crank assembly, when the crank member is rotated about the central axis of rotation, the sprocket member also rotates about the central axis of rotation. At this time, if the chain is disposed obliquely between the front sprocket and the rear sprocket, the sprocket member acts on the axial direction parallel to the central axis of rotation by the tension of the chain. In this case, the sprocket member is moved in the axial direction with respect to the crank member by the sliding mechanism, so that the degree of inclination of the chain between the front sprocket and the rear sprocket becomes small. At the time of this sliding, one of the sprocket member and the crank member is biased toward the other by the elastic member of the loosening prevention mechanism to prevent loosening of the sprocket member and the crank member. Thereby, it is possible to prevent the driving efficiency from being lowered due to looseness.

The sliding mechanism may further include: a first sliding portion that is integrally attached to the crank member; a second sliding portion that is integrally attached to the sprocket member; and at least one rolling element that is disposed on the first sliding portion and the second sliding portion Between the ministries. In this case, the sprocket member slides with respect to the crank member via the rolling elements, so that the sliding resistance is reduced and the sprocket member smoothly slides.

The loosening prevention mechanism includes: a contact member mounted to the crank member and the sprocket member And one of pressing the adjustment member mounted to the other of the crank member and the sprocket member and including the elastic member; and the elastic member is in contact with the contact member. In this case, by adjusting the elastic force of the elastic member, even if the gap between the first sliding portion and the second sliding portion changes due to abrasion or the like, looseness can be prevented.

The elastic member may include the first end portion and the second end portion, and the first end portion of the elastic member is in contact with the contact member. The pressing adjustment member may include a rotation member that engages the second end portion of the elastic member, and an operation member that rotates the rotation member. In this case, the elastic member can be easily adjusted by rotating the rotary member with the operating member to move the second end portion of the elastic member.

A first threaded portion may be formed in the other of the crank member and the sprocket member, and the operating member includes a second threaded portion that is screwed to the first threaded portion. In this case, the elastic force can be finely adjusted by rotating the second thread portion.

The contact member may also be a member made of a synthetic resin extending in the axial direction parallel to the central axis of rotation. In this case, even if the second sliding portion moves in the axial direction with respect to the first sliding portion, the first end portion of the elastic member can smoothly move.

The contact member may also have a sliding groove that extends in an axial direction parallel to the central axis of rotation and that slides the first end portion of the elastic member. In this case, since the first end portion of the elastic member is guided by the sliding groove, even if the second sliding portion moves in the axial direction with respect to the first sliding portion, the first end portion of the elastic member is surely guide.

The contact member may be detachably fixed to one of the first sliding portion and the second sliding portion. In this case, the contact member can be replaced even if the contact member is worn.

A bicycle crank assembly according to another aspect of the present invention includes a crank member, a sprocket member, a sliding mechanism, and a plurality of dust covers. The sprocket member has a central axis of rotation. The sliding mechanism includes a plurality of sliding portions that couple the sprocket member and the crank member so as to be slidable in an axial direction parallel to the central axis of rotation. A plurality of dust covers are attached to each of the plurality of sliding portions.

In the bicycle crank assembly, when the crank member is rotated about the central axis of rotation, the sprocket member also rotates about the central axis of rotation. At this time, if the chain is disposed obliquely between the front sprocket and the rear sprocket, the sprocket member acts on the axial direction parallel to the central axis of rotation by the tension of the chain. In this case, the sprocket member is moved in the axial direction with respect to the crank member by the sliding mechanism, so that the degree of inclination of the chain between the front sprocket and the rear sprocket becomes small. The plurality of sliding portions of the sliding mechanism are not covered once, but are individually covered by a plurality of dust covers. Therefore, it is possible to efficiently prevent liquid and foreign matter from intruding into the sliding portion. Thereby, it is possible to prevent the driving efficiency from being lowered due to the intrusion of liquid or foreign matter. Further, since the plurality of sliding portions of the sliding mechanism are not covered once, but are individually covered by the plurality of dust covers, the dust cover can be individually effected.

Each of the plurality of sliding portions may include: a first sliding portion that is integrally attached to the crank member; a second sliding portion that is integrally attached to the sprocket member; and at least one rolling element that is disposed on the first sliding portion Between the portion and the second sliding portion. In this case, since the first sliding portion and the second sliding portion are in rolling contact with the rolling elements, the sliding resistance is reduced. Therefore, the sprocket member can be moved quickly and smoothly with respect to the crank member in the axial direction parallel to the central axis of rotation.

The rolling elements can also be provided with a plurality of rolling elements. Each of the plurality of rolling elements is disposed between the first sliding portion and the second sliding portion. Each of the plurality of sliding portions may further include a holder that holds at least a plurality of rolling elements at intervals in the circumferential direction. In this case, since a plurality of rolling elements are arranged at intervals in the circumferential direction, a plurality of rolling elements roll efficiently.

Each of the plurality of dust covers may cover the gap between the first sliding portion and the second sliding portion. In this case, even if the first sliding portion and the second sliding portion are displaced in the axial direction parallel to the central axis of rotation, the gap between the first sliding portion and the second sliding portion is sealed.

A bicycle crank assembly according to still another aspect of the present invention includes a crank member, a sprocket member, a sliding mechanism, and a sliding stroke amount adjusting mechanism. The sprocket member has a central axis of rotation. The slide mechanism couples the sprocket member and the crank member so as to be slidable in the axial direction parallel to the central axis of rotation. The sliding stroke amount adjustment mechanism adjusts the sliding stroke of the sprocket member with respect to the crank member.

The sliding stroke amount adjustment mechanism includes an abutting member that is attached to one of the crank member and the sprocket member, and is in contact with the other of the crank member and the sprocket member when the sliding mechanism slides. The abutting member includes an abutting portion that contacts the other of the crank member and the sprocket member, and a shaft portion that is smaller in diameter than the abutting portion.

In the bicycle crank assembly, when the crank member is rotated about the central axis of rotation, the sprocket member also rotates about the central axis of rotation. At this time, there is a case where the chain is disposed obliquely between the front sprocket and the rear sprocket, and the sprocket member acts on the axial direction parallel to the central axis of rotation by the tension of the chain. In this case, the sprocket member is moved in the axial direction with respect to the crank member by the sliding mechanism, so that the degree of inclination of the chain between the front sprocket and the rear sprocket becomes small. The sliding stroke of the sprocket member relative to the crank member can be adjusted by the sliding stroke amount adjustment mechanism. Specifically, the amount of sliding stroke can be adjusted by arranging, for example, the shaft portion of the abutting member so as to be positionable at an arbitrary position in the axial direction. Therefore, by adjusting the amount of sliding stroke according to the frame of the bicycle, it is possible to prevent the chain from interfering with the frame. Thereby, it is possible to prevent the driving efficiency from being lowered due to the contact of the chain with the frame.

The sliding stroke amount adjustment mechanism may include at least one of the first slip stroke amount adjustment unit and the second slip stroke amount adjustment unit. The first sliding stroke amount adjusting unit may adjust the amount of sliding stroke in the first axial direction that is separated from the crank member along the rotation center axis. The second sliding stroke amount adjusting unit may adjust the amount of sliding stroke in the second axial direction opposite to the first axial direction. In this case, the amount of sliding stroke in both directions of the axial direction of the chain parallel to the central axis of rotation can be adjusted, so that it is easy to ensure the stroke amount of the sprocket even if the chain is not adjusted in contact with the frame. .

The second sliding stroke amount adjusting unit may be disposed on the opposite side of the first sliding stroke amount adjusting unit with respect to the rotation center axis as the rotation center axis. In this case, the balance can be well configured. The first sliding stroke amount adjusting unit and the second sliding stroke amount adjusting unit.

The sliding stroke amount adjustment mechanism may further include a cushioning member attached to the other of the crank member and the sprocket member. The cushioning member may also be in contact with the abutting portion of the abutting member. In this case, the abutting member does not directly contact the other of the crank member and the sprocket member, but is in contact with the cushioning member, so that the impact at the time of contact can be alleviated.

A bicycle crank assembly according to still another aspect of the present invention includes a crank member, a sprocket member, a sliding mechanism, and a loosening prevention mechanism. The sprocket member has a central axis of rotation. The sliding mechanism includes a sliding portion that couples the sprocket member and the crank member so as to be slidable in an axial direction parallel to the central axis of rotation. The loosening prevention mechanism is provided on the sliding portion to prevent looseness of the crank member and the sprocket member.

In the bicycle crank assembly, when the crank member is rotated about the central axis of rotation, the sprocket member also rotates about the central axis of rotation. At this time, there is a case where the chain is disposed obliquely between the front sprocket and the rear sprocket, and the sprocket member acts on the axial direction parallel to the central axis of rotation by the tension of the chain. In this case, the sprocket member is moved in the axial direction parallel to the central axis of rotation with respect to the crank member by the sliding mechanism, so that the degree of inclination of the chain between the front sprocket and the rear sprocket becomes small. At the time of this sliding, since the loosening prevention mechanism is provided in the sliding portion where the looseness is generated, even if the sliding portion is worn, the sprocket member and the crank member can be reliably prevented from loosening. Thereby, it is possible to prevent the driving efficiency from being lowered due to looseness.

The sliding mechanism can also include a plurality of sliding portions. In this case, since the sliding mechanism includes a plurality of sliding portions, the sprocket member can be smoothly slid with respect to the crank member.

The loosening prevention mechanism may be provided in each of the plurality of sliding portions. In this case, loosening can be prevented corresponding to the wear of the respective sliding portions.

The sliding portion may include a first sliding portion that is integrally attached to the crank member, a second sliding portion that is integrally attached to the sprocket member, and a plurality of rolling elements that are disposed on the first sliding portion and the second portion. Between the sliding parts. The loosening prevention mechanism can also be disposed in the first sliding portion and the second At least one of the sliding portions. In this case, by moving at least one of the first sliding portion and the second sliding portion toward the other, it is possible to individually prevent the sliding portions from being loosened.

The sliding mechanism may further include a retainer that holds the plurality of rolling elements at intervals in the circumferential direction. In this case, since a plurality of rolling elements are arranged at intervals in the circumferential direction, a plurality of rolling elements roll efficiently.

The loosening prevention mechanism may include a first cam portion, a pressing member, and an adjustment member. The first cam portion may be provided in one of the first sliding portion and the second sliding portion. The pressing member may include a second cam portion that is in contact with the first cam portion, and one of the first sliding portion and the second sliding portion may be pressed toward the other of the first sliding portion and the second sliding portion. The adjustment member can also displace the pressing member to relatively move the second cam portion with respect to the first cam portion. In this case, when the pressing member is displaced by the adjusting member, the second cam portion relatively moves with respect to the first cam portion, and the pressing member slides one of the first sliding portion and the second sliding portion toward the first sliding portion. The other portion is pressed against the second sliding portion. Thereby, the looseness of the sliding portion can be prevented.

The first cam portion may have a first inclined surface, and the second cam portion may have a second inclined surface that contacts the first inclined surface. In this case, when the pressing member is displaced in the direction intersecting the first inclined surface by the adjusting member, one of the first sliding portion and the second sliding portion can be adjusted to the first sliding portion and the second sliding portion. The other of the departments presses the force.

The pressing member may include a first threaded portion formed along a direction in which the pressing member is displaced, and the adjusting member includes a second threaded portion that is screwed to the first threaded portion. In this case, when the adjustment member is rotated, the pressing member is displaced by the relative movement of the first screw portion with respect to the second screw portion, so that the pressing force can be finely adjusted.

The first screw portion may be a female screw portion and the second screw portion may be a male screw portion. In this case, the adjustment member can be formed in a rod shape, and the screw hole can be provided in the pressing member. Therefore, the adjustment structure can be downsized.

The loosening prevention mechanism may include a first cam portion, a pressing member, and an elastic member. The first cam portion may be provided in one of the first sliding portion and the second sliding portion. Pressing member can also The second cam portion that is in contact with the first cam portion is included, and one of the first sliding portion and the second sliding portion can be pressed toward the other of the first sliding portion and the second sliding portion. The elastic member may also bias the pressing member in a direction in which the second cam portion relatively moves relative to the first cam portion. In this case, the elastic member urges the pressing member such that one of the first sliding portion and the second sliding portion is pressed toward the other of the first sliding portion and the second sliding portion by the pressing member. Thereby, the looseness of the sliding portion can be prevented.

The first cam portion may have a first inclined surface, and the second cam portion may have a second inclined surface that contacts the first inclined surface. In this case, when the pressing member is displaced in the direction intersecting the first inclined surface by the biasing member, one of the first sliding portion and the second sliding portion can be moved to the first sliding portion and the second portion. The other of the sliding portions approaches and one presses the force of the other to adjust.

The drive efficiency can be prevented from being lowered in the crank assembly in which the sprocket member can move in the direction of the rotation axis.

10‧‧‧Bicycle crank assembly

12‧‧‧ crank member

14‧‧‧Sprocket members

16‧‧‧Sliding mechanism

20‧‧‧ crankshaft

22‧‧‧Loose prevention mechanism

24‧‧‧ dust cover

24a‧‧‧ first opening

24b‧‧‧2nd opening

24c‧‧‧1st cover

24d‧‧‧2nd cover

24e‧‧‧ Bellows Department

26‧‧‧Sliding stroke adjustment mechanism

26a‧‧‧1st sliding stroke amount adjustment unit

28‧‧‧Removable components without tools

28a‧‧‧ buckle

28b‧‧‧Ringed spring part

28c‧‧‧Operation handle

30‧‧‧Sliding stroke limit mechanism

40‧‧‧ Arms

40a‧‧‧Axis mounting holes

40b‧‧‧ pedal mounting hole

40c‧‧‧Links

42‧‧‧Support Department

42a‧‧‧Support Unit Ontology

42b‧‧‧1st installation department

42c‧‧‧Link hole

42d‧‧‧1st mounting recess

42e‧‧‧ bottom

42f‧‧‧1st bracket

42g‧‧‧鸠尾槽

44‧‧‧Sprocket installation

44a‧‧‧Installation body

44b‧‧‧Second Installation Department

44c‧‧‧2nd mounting recess

44e‧‧‧Linked convex

44f‧‧‧1st slot

44g‧‧‧2nd slot

44h‧‧‧ pedestal

44i‧‧‧ Female thread

45‧‧‧Base member

45a‧‧‧Base body

45b‧‧‧ Nut components

45c‧‧‧Base section

45d‧‧‧ bracket section

45e‧‧‧through hole

45f‧‧‧ positioning recess

45g‧‧‧Adjustment hole

45h‧‧‧slit

45i‧‧‧ female thread

46‧‧‧Sprocket body

46a‧‧‧Sprocket teeth

46b‧‧‧Connection recess

48‧‧‧Sliding section

50‧‧‧1st sliding part

50a‧‧‧ inside

50b‧‧‧Outside

50c‧‧‧Inside guide groove

52‧‧‧2nd sliding part

52a‧‧‧Outside

52b‧‧‧ inside

52c‧‧‧Outer guiding groove

54‧‧‧ rolling elements

56‧‧‧keeper

56a‧‧‧1st end

56b‧‧‧1st snap projection

56d‧‧‧2nd snap projection

60‧‧‧Contact members

60a‧‧‧sliding trough

60b‧‧‧ recess

62‧‧‧ Pressing adjustment member

64‧‧‧ Positioning members

66‧‧‧Flexible components

66a‧‧1st end

66b‧‧‧2nd end

66c‧‧ Thread Department

68‧‧‧Rotary components

68a‧‧‧Rings

68b‧‧‧Contacts

68c‧‧‧Clamping recess

68d‧‧‧Contact surface

70‧‧‧Action components

70a‧‧‧ Male thread department

70b‧‧‧Tool snap hole

72‧‧‧Fixed components

72a‧‧‧ head

72b‧‧‧Axis

72c‧‧‧ Male thread department

72d‧‧‧Tools and Engagement Department

74‧‧‧ Cover member

74a‧‧‧Gap section

76‧‧‧Retaining components

78‧‧‧screw components

80‧‧‧Abutment components

80a‧‧‧Apartment

80b‧‧‧Axis

80c‧‧‧ Male thread department

80d‧‧‧Tools and Engagement Department

82‧‧‧ cushioning members

82a‧‧‧ head

82b‧‧‧Axis

84‧‧‧2nd bracket

84a‧‧‧Adjustment hole

84b‧‧‧slit

86‧‧‧ Nut components

86a‧‧‧Mask thread

88‧‧‧3rd bracket

88a‧‧‧Mounting holes

90‧‧‧stops

92‧‧‧4th bracket

110‧‧‧Bicycle crank assembly

112‧‧‧ crank member

114‧‧‧Sprocket members

116‧‧‧Sliding mechanism

126‧‧‧Sliding stroke adjustment mechanism

126b‧‧‧2nd sliding stroke amount adjustment unit

190‧‧‧5th bracket

190a‧‧‧Adjustment hole

190b‧‧‧slit

210‧‧‧Bicycle crank assembly

212‧‧‧ crank member

214‧‧‧Sprocket components

216‧‧‧Sliding mechanism

222‧‧‧Loose prevention mechanism

224‧‧‧ dust cover

224a‧‧‧1st dust cover

224b‧‧‧2nd dust cover

232‧‧‧ buckle

242‧‧‧Support Department

242a‧‧‧Support Unit Ontology

242b‧‧‧1st Installation Department

242c‧‧‧1st mounting recess

242d‧‧‧1st mounting recess

244‧‧‧Sprocket installation

244a‧‧‧Installation body

244b‧‧‧2nd Installation Department

244c‧‧‧1st Containment Department

244d‧‧‧2nd accommodating department

244e‧‧‧1 hole

244f‧‧‧2nd hole

246‧‧‧Sprocket body

248‧‧‧Sliding section

250‧‧‧1st sliding part

250a‧‧‧ inside

250b‧‧‧ outside side

250c‧‧‧Inside guide groove

252‧‧‧2nd sliding part

252b‧‧‧ inside

252c‧‧‧Outer guide groove

252d‧‧‧1st cam section

252e‧‧‧1st inclined surface

254‧‧‧ rolling elements

256‧‧‧keeper

294‧‧‧ Pressing members

294a‧‧‧2nd cam department

294b‧‧‧2nd inclined surface

294c‧‧‧ female thread

298‧‧‧Adjusting components

298a‧‧‧ Screw Department

298b‧‧‧Installation shaft

298c‧‧‧ring groove

298d‧‧‧Tool snap hole

310‧‧‧Bicycle crank assembly

322‧‧‧Loose prevention mechanism

334‧‧‧ force components

344c‧‧‧1st Containment Department

344d‧‧‧2nd accommodating department

344e‧‧‧ screw hole

394‧‧‧ Pressing members

394a‧‧‧2nd cam department

394b‧‧‧2nd inclined surface

394c‧‧‧Support recess

398‧‧‧Adjustment components

398a‧‧‧ Screw Department

398b‧‧‧Support shaft

398c‧‧ ‧ spring protrusion

398d‧‧‧Tools and Engagement Department

A‧‧‧Reorientation

C‧‧‧Rotation center axis

C1‧‧‧1st axial

C2‧‧‧2nd axial

DD‧‧‧ drive rotation direction

L‧‧‧ Straight line

P‧‧‧Press direction

S‧‧‧Sliding stroke

‧‧‧‧ angle

Fig. 1 is a perspective rear elevational view of a bicycle crank assembly according to a first embodiment of the present invention.

Figure 2 is a front view of the bicycle crank assembly.

Figure 3 is an exploded perspective view showing a portion of a bicycle crank assembly.

Figure 4 is an exploded perspective view of the remaining configuration of the bicycle crank assembly.

Fig. 5 is a rear elevational view of the crank assembly in a state in which the dust cover is removed.

Fig. 6 is a cross-sectional view taken along line VI-VI of Fig. 5 .

Fig. 7 is a cross-sectional view taken along line VII-VII of Fig. 5 .

Figure 8 is a perspective view of the loosening prevention mechanism.

Figure 9 is a plan view of the loosening prevention mechanism.

Figure 10 is an exploded perspective view of the loosening prevention mechanism.

Fig. 11 is a cross-sectional view corresponding to Fig. 7 showing a modification of the first embodiment.

Figure 12 is a front view of a bicycle crank assembly according to a second embodiment of the present invention.

Fig. 13 is a rear view corresponding to Fig. 6 in the second embodiment.

Fig. 14 is an enlarged cross-sectional view showing the loosening preventing mechanism of the second embodiment.

Fig. 15 is an enlarged cross-sectional view corresponding to Fig. 14 showing a loosening preventing mechanism according to a modification of the second embodiment.

As shown in FIGS. 1 to 3, a bicycle crank assembly (hereinafter referred to as a crank assembly) 10 according to a first embodiment of the present invention includes a crank member 12, a sprocket member 14 having a central axis of rotation C, and a slide mechanism 16. Further, the crank assembly 10 further includes a crank shaft 20, a loosening prevention mechanism 22, a plurality of dust covers 24, a sliding stroke amount adjusting mechanism 26, a tool-free stopper member 28, and a sliding stroke amount restricting mechanism 30. The crankshaft 20 and the tool-free stop member 28 can also be selectively omitted, as desired. The slide mechanism 16 slidably couples the sprocket member 14 and the crank member 12 in the direction of the rotation center axis C and is integrally rotatable. The loosening prevention mechanism 22 prevents loosening of the crank member 12 and the sprocket member 14. A plurality of dust covers 24 are attached to the slide mechanism 16 to prevent foreign matter from entering the slide mechanism 16. The sliding stroke amount adjustment mechanism 26 can adjust the amount of sliding stroke of the sprocket member 14 with respect to the crank member 12. The tool-free stop member 28 stops the sprocket body 46 of the sprocket member 14 with respect to the sprocket mounting portion 44 without the use of a tool.

<crank member>

The crank member 12 is a member made of a light metal such as aluminum. The crank member 12 includes an arm portion 40 and a support portion 42 that is rotatable integrally with the arm portion 40 about the rotation center axis C. As shown in FIG. 3, the arm portion 40 constitutes a crank arm that extends in the radial direction of the central axis of rotation C. The arm portion 40 has a shaft attachment hole 40a that is integrally coupled to the crank shaft 20 at one end thereof. At the other end of the arm portion 40, a pedal mounting hole 40b for pedal mounting is formed in the form of a female screw hole. On the outer peripheral side of the shaft attachment hole 40a, for example, the coupling protrusion 40c that is press-fitted or connected to the support portion 42 so as to be integrally rotatable is formed to protrude in a ring shape. Shaft mounting hole 40a and connecting protrusion 40c is formed, for example, with serrations.

The support portion 42 is slidably supported by the sprocket member 14 via the slide mechanism 16 so as to be rotatable integrally. As shown in FIGS. 4, 5, and 6, the support portion 42 includes a support portion main body 42a formed in a substantially square shape, and a plurality of outer peripheral surfaces of the support portion main body 42a integrally formed in the axial direction parallel to the rotation center axis C. (for example, four) first mounting portions 42b. The support main body 42a has a coupling hole 42c that is coupled to the coupling protrusion 40c of the arm portion 40 so as to be rotatable integrally. The length of the first mounting portion 42b in the axial direction is larger than the support portion main body 42a. The first attachment portion 42b is formed to protrude from the back surface and the front surface of the support portion main body 42a. The first attachment portion 42b includes a plurality of (for example, four) first attachment recesses 42d that are recessed in a flat U shape and formed on the outer peripheral portion. The first attachment recess 42d is formed over the entire length of the outer circumference of the outer peripheral portion of the first attachment portion 42b. As shown in FIG. 4, the first attachment recess 42d is formed to gradually decrease in width from the back side toward the front side (from the left side toward the right side in FIG. 4). Moreover, as shown in FIG. 6, the bottom part 42e of the 1st mounting recessed part 42 d is formed so that the depth may become shallow from the back side toward the front side (from the left side of the FIG. As shown in FIG. 5, the bottom portion 42e of the first attachment recess 42d is disposed such that the angle ? formed by the straight line L connecting the center of the rotation center axis C and the bottom portion 42e and the bottom portion 42e are acute. Thereby, the rotational driving force can be efficiently transmitted from the crank member 12 to the sprocket member 14, and the sprocket member 14 can be slid in the axial direction with respect to the crank member 12. In addition, in FIG. 5, the dust cover 24 is abbreviate|omitted.

<sprocket member>

The sprocket member 14 is a member made of metal such as aluminum, titanium, or iron. The sprocket member 14 includes a sprocket mounting portion 44 and a sprocket body 46. The sprocket attachment portion 44 is integrally rotatable via the slide mechanism 16 and is slidably supported by the support portion 42 in the axial direction parallel to the rotation center axis C.

As shown in FIGS. 3, 5, and 6, the sprocket attachment portion 44 includes a mounting portion main body 44a formed in a tubular shape and a plurality of inner circumferential surfaces integrally formed on the mounting portion main body 44a in the axial direction (for example, 4) The second mounting portion 44b. The second mounting portion 44b is opposed to the first mounting portion 42b. Mode configuration. The second attachment portion 44b is disposed in parallel with the first attachment portion 42b. The length of the second attachment portion 44b in the axial direction is larger than the attachment portion main body 44a, and is preferably formed to have the same length as the first attachment portion 42b. Therefore, the second attachment portion 44b is formed to protrude from the back surface and the front surface of the attachment portion main body 44a. The second attachment portion 44b includes a plurality of (for example, four) second attachment recesses 44c that are recessed in a flat U shape and formed in the inner peripheral portion. The second attachment recess 44c is formed over the entire length of the inner circumferential portion of the second attachment portion 44b. As shown in FIG. 3, the second attachment recess 44c is formed to gradually decrease in width from the back side toward the front side (from the left side toward the right side in FIG. 3). Moreover, as shown in FIG. 6, the bottom part 44d of the 2nd mounting recessed part 44c is formed so that the depth may become shallow from the back side toward the front side (from the left side of the FIG.

The attachment portion main body 44a includes a coupling convex portion 44e that integrally connects the sprocket body 46 to the outer circumferential surface. Further, the outer peripheral surface has a first groove 44f (see FIG. 6) for attaching the positioning member 64 for positioning the sprocket body 46 in the axial direction, and a second groove 44g for attaching the tool-free stopper member 28 (refer to Figure 6). The positioning member 64 is, for example, a C-shaped buckle.

Moreover, as shown in FIG. 3, the attachment part main body 44a includes the pedestal 44h which protrudes in the radial direction inner side, and the base member 45 which is formed in the inner peripheral surface, and the base member 45 fixed to the pedestal 44h. The base member 45 is provided to attach the loosening prevention mechanism 22 to the sprocket member 14. A female screw portion 44i for fixing the loosening preventing mechanism 22 together with the base member 45 is formed on the inner side surface of the pedestal 44h. As shown in FIG. 8, the base member 45 is fixed to the pedestal 44h together with the loosening prevention mechanism 22. The base member 45 is fixed to the pedestal 44h by the following fixing member 72 of the loosening prevention mechanism 22. The base member 45 includes a base body 45a and a nut member 45b attached to the base body 45a. The base body 45a includes a base portion 45c and a bracket portion 45d formed to be orthogonal to the base portion 45c. The base portion 45c includes a through hole 45e through which the fixing member 72 can pass and a positioning recess 45f positioned at the pedestal 44h. The positioning recess 45f is formed to face the pedestal 44h. The bracket portion 45d has an adjustment hole 45g and a slit 45h through which the operation member 70 described below can pass. The adjustment hole 45g and the through hole 45e are formed such that the central axis of the adjustment hole 45g is not parallel to the central axis of the through hole 45e. The slit 45h is formed orthogonal to the adjustment hole 45g. to The slit 45h is detachably attached to the nut member 45b. The nut member 45b includes a female screw portion 45i. The female screw portion 45i is an example of the first screw portion. Further, the female screw portion may be directly formed in the adjustment hole 45g without providing the nut member 45b. In this case, the slit 45h is not required. However, if the nut member 45b is provided, even if the female screw portion 45i is broken, the nut member 45b can be replaced only without replacing the base member 45.

As shown in FIG. 3, the sprocket body 46 includes a plurality of sprocket teeth 46a on the outer peripheral portion. The sprocket body 46 is rotatably and detachably coupled to the sprocket attachment portion 44. The sprocket body 46 includes a plurality of coupling recesses 46b that are integrally rotatable and detachably engageable with the coupling projections 44e at the inner peripheral portion. The sprocket body 46 is positioned in the axial direction on the outer circumferential surface of the sprocket mounting portion 44 by the positioning member 64 attached to the first groove 44f and the tool-free stopper member 28 attached to the second groove 44g. It moves and rotates integrally with the sprocket mounting portion 44.

<sliding mechanism>

As shown in FIGS. 4-6, the sliding mechanism 16 includes a plurality of (eg, four) sliding portions 48. In the present embodiment, the plurality of sliding portions 48 are arranged at substantially equal intervals in the circumferential direction. Each of the plurality of sliding portions 48 includes a first sliding portion 50, a second sliding portion 52, at least one rolling element 54, and a retainer 56. In the present embodiment, the first sliding portion 50 is integrally attached to the crank member 12, and the second sliding portion 52 is integrally attached to the sprocket member 14.

The first sliding portion 50 is integrally attached to the first mounting recess 42d provided in the first mounting portion 42b of the support portion 42 of the crank member 12, for example, by being attached. The first sliding portion 50 is disposed in parallel with the rotation center axis C and is formed to have the same length as the first mounting portion 42b. As shown in FIGS. 4 and 6, the first sliding portion 50 has an inner side surface 50a that is engaged with the first mounting recess 42d. Therefore, the inner side surface 50a of the first sliding portion 50 is formed to gradually decrease in width from the back side toward the front side, and is formed to be gradually thinner from the back side toward the front side. The outer side surface 50b of the first sliding portion 50 has an inner guide groove 50c that guides the rolling element 54 in a circular arc shape.

The second sliding portion 52 is integrally attached to the sprocket member 14 by, for example, being attached. The second mounting recess 44c of the second mounting portion 44b of the sprocket mounting portion 44. The second sliding portion 52 is disposed in parallel with the rotation center axis C and is formed to have the same length as the second mounting portion 44b. As shown in FIGS. 4 and 6, the second sliding portion 52 has a side surface 52a that is engaged with the second mounting recess 44c. Therefore, the outer surface 52a of the second sliding portion 52 is formed to be gradually narrowed from the back side toward the front side, and is formed to be gradually thinner from the back side toward the front side. The inner side surface 52b of the second sliding portion 52 has an outer side guide groove 52c having a circular arc-shaped cross section that guides the rolling elements 54.

At least one rolling element 54 is disposed between the first sliding portion 50 and the second sliding portion 52. In the first embodiment, the rolling elements 54 are, for example, beads made of steel, and two sliding portions 48 are provided at intervals along the axial direction parallel to the central axis of rotation C. The retainer 56 holds the rolling elements 54 at intervals in the axial direction. The rolling elements 54 may also be needle-shaped or roll-shaped.

As shown in FIG. 4, the first end 56a of the retainer 56 in the circumferential direction includes the first engagement projection 56b, and the first engagement projection 56b is engaged with the first attachment portion 42b so as not to be movable in the axial direction. The holder 56 is provided with the second engagement projection 56d at the second end 56b opposite to the first end 56a, and the second engagement projection 56d is engaged with the second attachment portion 44b so as not to be movable in the axial direction. Thereby, the retainer 56 is attached to each of the sliding portions 48 so as not to be movable in the axial direction.

Here, the first mounting recess 42d and the second mounting recess 44c are formed to be inclined with respect to a plane parallel to the rotation center axis C, and the first sliding portion 50 and the second sliding portion 52 are also formed to be inclined. Therefore, it is possible to prevent the adhesive from leaking from the subsequent surface when the first sliding portion 50 and the second sliding portion 52 are attached to the first mounting recess 42d and the second mounting recess 44c. Thereby, even if the first sliding portion 50 and the second sliding portion 52 are attached to the first mounting recess 42d and the second mounting recess 44c, the operation of wiping off the leaking adhesive can be reduced.

<crankshaft>

The crankshaft 20 is a hollow cylindrical member in the first embodiment. The crankshaft 20 is coupled to the crank member 12 so as to be integrally rotatable by press-fitting or subsequent. However, the crankshaft 20 can also be detachably attached to the crank member 12 by, for example, a screw member.

<Loose prevention mechanism>

As shown in FIGS. 8 and 9, the loosening prevention mechanism 22 includes a contact member 60 and a pressing adjustment member 62 including the elastic member 66. The contact member 60 is attached to one of the crank member 12 and the sprocket member 14. The press adjustment member 62 is attached to the other of the crank member 12 and the sprocket member 14. In the present embodiment, the contact member 60 is attached to the support portion 42 of the crank member 12, and the press adjustment member 62 is attached to the sprocket attachment portion 44 of the sprocket member 14. Furthermore, the arrangement of the contact member 60 and the pressing adjustment member 62 may be reversed.

The contact member 60 is a rod-like member that extends in the direction of the central axis of rotation C. The contact member 60 is preferably made of a synthetic resin such as polyacetal or polyamide resin which is relatively hard and has high sliding properties. The first end portion 66a of the elastic member 66 is in contact with the contact member 60. A sliding groove 60a for sliding the first end portion 66a in contact with the sliding operation of the sliding mechanism 16 is formed along the rotation center axis C on the surface of the contact member 60 that is in contact with the first end portion 66a. The sliding groove 60a is formed, for example, in a semicircular shape in cross section. The contact member 60 is detachably fixed to the first bracket 42f formed on the support portion 42 in the axial direction parallel to the rotation center axis C by the screw member 78. A circular recess 60b for contacting the front end of the screw member 78 is formed on the surface of the screw member 78 on the side of the contact member 60.

In addition, in FIG. 8, the 1st bracket 42f is shown by the two-dot chain line. A dovetail groove 42g having a narrower opening than the bottom is formed in the first bracket 42f. The contact member 60 has a side that can be engaged with the outer side of the dovetail groove 42g. The contact member 60 is detachably attached to the dovetail groove 42g so as to be positionally adjustable in the direction of the rotation center axis C and displaced in a direction orthogonal to the rotation center axis C. The screw member 78 is screwed to the first bracket 42f to press the contact member 60 toward the first end portion 66a, whereby the contact member 60 is fixed.

The pressing adjustment member 62 presses the contact member 60 by the elastic member 66, and biases the sprocket member 14 in the circumferential direction with respect to the crank member 12. Thereby, even when the sliding mechanism 16 wears and the sliding mechanism 16 is loosened, the sprocket member 14 is not loosened relative to the crank member 12.

As shown in FIG. 10, the pressing adjustment member 62 preferably includes an elastic member 66, a rotating member 68, an operating member 70, a fixing member 72, and a cover member 74. The elastic member 66 preferably includes a torsion coil spring including a first end portion 66a, a second end portion 66b, and a screw portion 66c provided between the first end portion 66a and the second end portion 66b. The first end portion 66a contacting the contact member 60 is curved in an arc shape, and the curved portion is in contact with the sliding groove 60a of the contact member 60. Thereby, the abrasion of the contact member 60 when the elastic member 66 slides relative to the contact member 60 can be alleviated. The second end portion 66b is bent in a direction away from the screw portion 66c. The elastic member 66 is mounted in a compressed state capable of generating an elastic force.

The rotation member 68 is rotatably supported by the fixing member 72 on the base portion 45c. The turning member 68 includes an annular portion 68a that is placed on the base portion 45c, and a contact portion 68b that protrudes outward and is formed on the outer peripheral portion of the annular portion 68a and is in contact with the operating member 70. The annular portion 68a includes an engagement recess 68c into which the second end portion 66b of the elastic member 66 is engaged. The contact portion 68b is disposed to face the bracket portion 45d, and includes a contact surface 68d for contacting the front end portion of the operating member 70.

The operating member 70 includes a male screw portion 70a that is screwed to the nut member 45b attached to the bracket portion 45d. The male screw portion 70a is an example of a second screw portion. The operating member 70 is provided with a tool engaging hole 70b at the base end that can be engaged with a tool such as a hexagonal wrench. When the operating member 70 is rotated, the second end portion 66b of the elastic member 66 moves, and the elastic force (elastic force) of the elastic member 66 changes. Thereby, the pressing force of the loosening prevention mechanism 22 can be adjusted.

The fixing member 72 is provided to fix the loosening prevention mechanism 22 to the sprocket member 14 together with the base member 45. The fixing member 72 includes a large-diameter head portion 72a, a shaft portion 72b, and a male screw portion 72c. The head portion 72a includes a tool engagement portion 72d that can engage a tool such as a hex wrench. The shaft portion 72b is wound around the outer peripheral surface with the elastic member 66, and is rotatably supported by the rotary member 68. The male screw portion 72c is smaller in diameter than the shaft portion 72b, and is screwed to the female screw portion 44i of the pedestal 44h.

The cover member 74 is provided to prevent foreign matter from adhering to the elastic member 66. Outer cover The member 74 is a thin cylindrical member, and a notch portion 74a that passes through the cover member 74 is formed at one end portion in order to bring the first end portion 66a side of the elastic member 66 into contact with the contact member 60.

In the loosening prevention mechanism 22 configured in this manner, when the sprocket member 14 is slid in the axial direction parallel to the central axis of rotation C by the tension of the chain, the elastic member 66 exerts an elastic force on the contact member 60, so that it is less likely to be generated. The sprocket member 14 is loose. Therefore, it is possible to prevent the driving efficiency from being lowered due to looseness.

<dust cover>

The dust cover 24 is preferably a member of an elastic system such as synthetic rubber. The dust cover 24 is attached to each of the plurality of sliding portions 48. The dust cover 24 covers the gap between the first sliding portion 50 and the second sliding portion 52. As shown in FIG. 2, FIG. 4, and FIG. 6, in the present embodiment, the dust cover 24 is a plurality of second mounting portions 44b that are a plurality of first mounting portions 42b and sprocket mounting portions 44 of the support portion 42. And the sliding portion 48 is formed so as to have a bag shape having a space inside. The dust cover 24 includes a first opening 24a, a second opening 24b, a first cover portion 24c, a second cover portion 24d, and a bellows portion 24e. The first opening 24a is provided to attach the dust cover 24 to the first attachment portion 42b. The second opening 24b is provided to attach the dust cover 24 to the second attachment portion 44b. The first cover portion 24c is connected to the first opening 24a and is provided to cover the first attachment portion 42b. The second cover portion 24d is adjacent to the second opening 24b and is provided to cover the second attachment portion 44b. The bellows portion 24e connects the first cover portion 24c and the second cover portion 24d. The bellows portion 24e covers the sliding portion 48 by elastic deformation even if the second sliding portion 52 slides with respect to the first sliding portion 50. The bellows portion 24e is disposed on the first sliding portion 50 and the second sliding portion 52 with respect to the opposing portion.

Each of the dust covers 24 is held by the support portion 42 and the sprocket attachment portion 44 by the two holding members 76. The holding member 76 is formed by bending a spring wire into a rectangular shape and bending it along the first cover portion 24c (or the second cover portion 24d) in the middle. The holding member 76 is disposed along the long side of the first opening 24a (or the second opening 24b). The holding member 76 is short-side in the first mounting portion Both sides of the 42b (or the second attachment portion 44b) in the circumferential direction are caught on the support portion 42 (or the sprocket attachment portion 44).

The dust cover 24 is attached to the inside of the first attachment portion 42b in a state in which the front opening is reversed before the respective sliding portions 48 are assembled. Then, when the assembly of the sliding portion 48 is completed, the reverse dust cover 24 is restored, and the second opening 24b is opened and attached to the outside of the second mounting portion 44b. Thereby, each of the sliding portions 48 is covered by the dust cover 24.

In the dust cover 24 of such a configuration, the plurality of sliding portions 48 are not covered once, but are individually covered by a plurality of dust covers 24. Therefore, it is possible to efficiently prevent liquid and foreign matter from entering the sliding portion 48. Thereby, it is possible to prevent the driving efficiency from being lowered due to the intrusion of liquid or foreign matter. Further, since the plurality of sliding portions 48 are individually covered by the plurality of dust covers 24, only the dust cover 24 that has deteriorated can be replaced.

Further, even if the sprocket member 14 slides with respect to the crank member 12, the bellows portion 24e is elastically deformed, so that the respective sliding portions 48 can be surely covered. Further, since the dust cover 24 is elastic, the sprocket member 14 is easily returned to the desired axial position parallel to the rotation center axis C with respect to the support portion 42 by the elastic force of the dust cover 24 (for example, 6 is the middle position of the sliding stroke).

<Sliding stroke amount adjustment mechanism>

The slide stroke amount adjustment mechanism 26 adjusts the amount of movement (sliding stroke amount) S (see FIG. 7) of the sprocket member 14 with respect to the axial direction of the crank member 12 parallel to the rotation center axis C. In the first embodiment, the sliding stroke amount adjusting mechanism 26 can move the sprocket member 14 by a maximum of 10 mm in the axial direction with respect to the crank member 12, for example. The slide stroke amount adjustment mechanism 26 includes at least one of the first slip stroke amount adjustment unit 26a and the second slip stroke amount adjustment unit 126b.

In the present embodiment, the sliding stroke amount adjustment mechanism 26 includes the first slip stroke amount adjustment unit 26a. The first sliding stroke amount adjusting portion 26a adjusts the amount of sliding stroke in the first axial direction C1 (see FIG. 7) in which the sprocket member 14 is separated from the crank member 12 and is parallel to the central axis of rotation C. whole.

As shown in FIGS. 3, 4, and 7, the first sliding stroke amount adjusting portion 26a includes an abutting member 80 that is attached to one of the crank member 12 and the sprocket member 14, and when the sliding mechanism 16 slides And the crank member 12 is in contact with the other of the sprocket members 14; and the cushioning member 82 is attached to the other of the crank member 12 and the sprocket member 14. The cushioning member 82 can also be selectively omitted.

In the present embodiment, the abutting member 80 is attached to the sprocket mounting portion 44 of the sprocket member 14, and the cushioning member 82 is provided to the support portion 42 of the crank member 12. Furthermore, the arrangement of the abutment member 80 and the cushioning member 82 may be reversed. As shown in FIG. 7, the abutting member 80 includes an abutting portion 80a that is in contact with the crank member 12, and a shaft portion 80b that is smaller in diameter than the abutting portion 80a. The shaft portion 80b includes a male screw portion 80c and a tool engagement portion 80d. The male screw portion 80c is screwed to the nut member 86, and the nut member 86 is provided on the second bracket 84 that protrudes inward in the radial direction and is formed on the inner circumferential surface of the attachment portion main body 44a of the sprocket attachment portion 44. The tool engagement portion 80d is a non-circular hole in which the shaft portion 80b is located on the opposite side of the abutting portion 80a and has a tool such as a hexagonal wrench. The second bracket 84 has an adjustment hole 84a through which the shaft portion 80b can pass, and a slit 84b to which the nut member 86 can be detachably attached. The nut member 86 includes a female screw portion 86a that is screwed to the male screw portion 80c. Further, the nut member 86 may be formed in the adjustment hole 84a without providing the nut member 86. In this case, the slit 84b is not required. When the nut member 86 is provided, even if the female screw portion 86a is broken, the nut member 86 can be replaced only without replacing the sprocket attachment portion 44.

The cushioning member 82 is a member of an elastic system such as synthetic rubber. The cushioning member 82 is in contact with the abutting portion 80a of the abutting member 80. As shown in FIGS. 4 and 7, the cushioning member 82 includes a hemispherical head portion 82a and a shaft portion 82b having a smaller diameter than the head portion 82a. The cushioning member 82 is fixed to the third bracket 88 which is formed to protrude radially outward from the back surface side of the outer peripheral surface of the support portion 42 by, for example. The shaft portion 82b is fitted into the mounting hole 88a formed in the third bracket 88.

In the first sliding stroke amount adjusting portion 26a having such a configuration, when the abutting member 80 is rotated by a tool or the like, the amount of sliding stroke in the first axial direction C1 of the sprocket member 14 can be easily adjusted. Thereby, the chain or sprocket member 14 can be adjusted so as not to be in contact with the bicycle frame.

<Sliding stroke amount limiting mechanism>

As shown in FIG. 7, the sliding stroke amount restricting mechanism 30 restricts the sliding stroke amount S of the sprocket member 14 along the rotation center axis C in the second axial direction C2 opposite to the first axial direction C2 to a fixed position. The sliding stroke amount restricting mechanism 30 is preferably disposed on the opposite side of the first slip stroke amount adjusting portion 26a with respect to the rotation center axis C. Therefore, it is preferable that the sliding stroke amount restricting mechanism 30 is disposed at a distance of substantially 180 degrees from the first sliding stroke amount adjusting portion 26a in the rotational direction.

The sliding stroke amount restricting mechanism 30 includes: a stopper portion 90 that is attached to one of the crank member 12 and the sprocket member 14; and a cushioning member 82 that is attached to the other of the crank member 12 and the sprocket member 14 And abuts against the stopper 90. In the present embodiment, the stopper portion 90 is formed to protrude inward in the radial direction and is formed in the inner peripheral portion of the attachment portion main body 44a of the sprocket attachment portion 44. The cushioning member 82 is fixed to, for example, the fourth bracket 92 which is formed to be substantially 180 degrees apart from the third bracket 88 in the circumferential direction and protrudes outward in the radial direction from the front side of the support portion 42.

<stopper without tools>

As shown in FIG. 3, the tool-free stopper member 28 is configured such that the sprocket body 46 is stopped in the axial direction parallel to the rotation center axis C with respect to the sprocket attachment portion 44, and can be manually used with respect to the sprocket mounting portion. 44 loading and unloading the components of the operating sprocket body 46. The tool-free stop member 28 includes a buckle 28a made of a resilient metal wire. The buckle 28a is formed, for example, by bending a metal wire. The buckle 28a includes an annular spring portion 28b and a pair of operating handles 28c. The annular spring portion 28b can be attached to the second groove 44g formed on the outer circumferential surface of the support portion 42. The annular spring portion 28b is formed to have a diameter smaller than the mounting diameter of the second groove 44g in the free state. The pair of operation knobs 28c extend radially outward from both ends of the annular spring portion 28b, and the annular spring portion 28b can be manually expanded in diameter compared to the second groove 44g. In this embodiment In the middle, the annular spring portion 28b is disposed such that both ends overlap in the circumferential direction. The pair of operation knobs 28c are formed by bending the both ends of the overlapping portions of the annular spring portion 28b outward in the radial direction and bending the tip end extending in a direction orthogonal to the direction in which the annular spring portion 28b extends. The annular spring portion 28b is expanded in diameter by pinching the pair of operation knobs 28c with the thumb and the index finger, and the tool-free stopper member 28 can be removed from the second groove 44g.

Next, the operation of the crank assembly 10 when the crank assembly 10 of the first embodiment having such a configuration is attached to the bracket attached to the bottom of the bicycle will be described.

If the position of the chain on the rear sprocket in the direction of the hub axis is displaced by the shifting operation, the sprocket body 46 is displaced toward the chain in the axial direction parallel to the central axis of rotation C by the tension acting on the chain. Move in direction. Therefore, the state in which the chain is obliquely disposed between the front sprocket and the rear sprocket is alleviated, and the rotation of the sprocket body 46 is efficiently transmitted to the rear sprocket via the chain.

Since the slide mechanism 16 of the present invention is configured to extend in the axial direction parallel to the central axis of rotation C, the support portion 42 and the sprocket attachment portion 44 can maintain high strength.

When the sprocket attachment portion 44 is loose relative to the support portion 42, the urging member 70 is rotated in the direction in which the thread is advanced (clockwise in the case of the right-handed thread) by the hex wrench, and is rotated by the rotary member 68. The elastic force of the second end portion 66b of the elastic member 66 is enhanced. Thereby, the looseness of the slide mechanism 16 can be prevented.

When the amount of movement of the sprocket attachment portion 44 is adjusted, the abutment member 80 is rotated by a hexagonal lever wrench to perform adjustment. When the abutting member 80 is rotated in the direction in which the thread advances (clockwise in the case of the right-handed thread), the stroke amount of the sprocket mounting portion 44 becomes small, and the abutting member 80 is swung in the direction in which the thread is retracted. Then, the stroke amount of the sprocket mounting portion 44 becomes large. Thereby, the stroke amount of the sprocket member 14 can be adjusted in such a manner that the chain or the sprocket member 14 does not contact the frame depending on the number of the rear sprocket or the frame size of the bicycle.

When the sprocket body 46 is removed, the operation handle 28c of the stopper member 28 without the tool is pinched by fingers, and the annular spring portion 28b is enlarged from the second projection groove 44e. 44g is removed. Thereby, the sprocket body 46 can be removed without using a tool.

<Modification of the first embodiment>

In the following description, with respect to the configuration corresponding to the configuration of the first embodiment, the symbols of the first embodiment are denoted by the same three-digit symbols of the last two digits, and the same configuration as that of the first embodiment is used. The symbol is indicated.

As shown in Fig. 11, the crank assembly 110 of the modified example is different from the first embodiment in the first embodiment. Specifically, the sliding stroke amount adjustment mechanism 126 includes a first slip stroke amount adjustment unit 26a and a second slide stroke amount adjustment unit 126b. The second sliding stroke amount adjusting portion 126b can adjust the amount of sliding stroke in the second axial direction C2 opposite to the first axial direction C1. The second sliding stroke amount adjusting portion 126b is preferably disposed on the opposite side of the first sliding stroke amount adjusting portion 26a with respect to the rotation center axis C. Therefore, the second slip stroke amount adjustment unit 126b is preferably disposed at a distance of substantially 180 degrees from the first slide stroke amount adjustment unit 26a in the rotation direction. Therefore, the second slip stroke amount adjustment unit 126b is disposed in the same circumferential position as the slide stroke amount restriction mechanism 30 of the first embodiment. Since the configuration of the first slip stroke amount adjustment unit 26a is the same as that of the first embodiment, the description thereof is omitted. The second axial C2 sprocket body 46 is oriented in the direction in which the crank member 12 approaches.

The second sliding stroke amount adjusting portion 126b includes an abutting member 80 that is attached to one of the crank member 12 and the sprocket member 14, and when the sliding mechanism 16 slides and the other of the crank member 12 and the sprocket member 14 One contact; and a cushioning member 82 mounted to the other of the crank member 12 and the sprocket member 14. The cushioning member 82 can also be selectively omitted. The cushioning member 82 is the same member as that of the first embodiment.

In the modified example, the abutting member 80 is also attached to the sprocket mounting portion 44 of the sprocket member 14, and the cushioning member 82 is also fixed to the fourth bracket 92 of the support portion 42 of the crank member 12.

The abutting member 80 has the same configuration as that of the first embodiment, and includes an abutting portion 80a that is in contact with the crank member 12 and a shaft portion 80b that is smaller in diameter than the abutting portion 80a. The shaft portion 80b includes a male screw portion 80c and a tool engagement portion 80d. The male threaded portion 80c is screwed to the nut member 86, the nut The member 86 is provided on the fifth bracket 190 that protrudes inward in the radial direction and is formed on the inner circumferential surface of the attachment portion main body 44a of the sprocket attachment portion 44. The tool engagement portion 80d is located on the opposite side of the abutment portion 80a with respect to the shaft portion 80b. The fifth bracket 190 is formed in the mounting portion main body 44a in the same circumferential direction and radial position as the stopper portion 90 of the first embodiment. The fifth bracket 190 has an adjustment hole 190a through which the shaft portion 80b can pass, and a slit 190b to which the nut member 86 can be detachably attached. The nut member 86 includes a female screw portion 86a that is screwed to the male screw portion 80c. Further, the nut member 86 may be formed in the adjustment hole 190a without providing the nut member 86. In this case, the slit 190b is not required. However, if the nut member 86 is provided, even if the female screw portion 86a is broken, the sprocket attachment portion 44 is not replaced and only the nut member 86 is replaced.

In such a configuration, when the abutting member 80 is rotated by a tool or the like in the first sliding stroke amount adjusting portion 26a, the amount of sliding stroke in the first axial direction C1 of the sprocket member 14 can be easily adjusted. Further, in the second sliding stroke amount adjusting portion 126b, when the abutting member 80 is rotated, the amount of sliding stroke in the second axial direction C2 of the sprocket member 14 can be easily adjusted. Thereby, even if the chain or the sprocket member 14 is not in contact with the bicycle frame, it is easy to ensure the sliding stroke amount S of the sprocket member 14.

<Second embodiment>

As shown in FIG. 12 and FIG. 13, the crank assembly 210 according to the second embodiment of the present invention is mainly different from the first embodiment in that the configuration of the slide mechanism 216 and the loosening prevention mechanism 222 (see FIG. 13) are provided in the slide mechanism 216. . The crank assembly 210 mainly includes a crank member 212, a sprocket member 214 having a rotation center axis C, a sliding mechanism 216, a crank shaft 20, a loosening prevention mechanism 222, a plurality of (for example, four) dust covers 224, and a sliding stroke amount adjustment mechanism. 226.

The slide mechanism 216 is configured such that the sprocket member 214 and the crank member 212 are slidable in the axial direction parallel to the rotation center axis C and are integrally rotatable. The loosening prevention mechanism 222 is provided on the sliding portion 248 to prevent loosening of the crank member 212 and the sprocket member 214.

<crank member>

The crank member 212 includes an arm portion 40 and a support portion 242. As shown in FIG. 13, the support portion 242 includes a substantially rectangular support portion main body 242a and a plurality of (for example, four) first mounting portions 242b similar to those of the first embodiment. The arrangement of the first attachment portion 242b is different from that of the first embodiment, but the configuration is the same. That is, the length of the first attachment portion 242b in the axial direction is larger than that of the support portion main body 242a. The first attachment portion 242b is formed to protrude from the back surface and the front surface of the support portion main body 42a. Similarly to the first attachment portion 42b of the first embodiment, the first attachment portion 242b includes a first attachment recess 242d that is inclined with respect to a plane parallel to the rotation central axis C. A first dust cover 224a of a dust cover 224 made of a plate material is screwed to both ends of the first mounting portion 242b in the axial direction parallel to the central axis of rotation C, for example. The first dust cover 224a covers both ends of the first mounting portion 242b in the axial direction.

<sprocket member>

In FIGS. 13 and 14, the sprocket member 214 is a member made of metal such as aluminum, titanium, or iron. Further, in Fig. 13, two of the four dust covers 224 are removed and drawn. The sprocket member 214 includes a sprocket mounting portion 244 and a sprocket body 246. The sprocket attachment portion 244 is integrally rotatable via the slide mechanism 216 and is slidably supported by the support portion 242 in the axial direction parallel to the rotation center axis C.

The sprocket attachment portion 244 includes a mounting portion main body 244a formed in a tubular shape and a plurality of (for example, four) second mounting portions 244b integrally formed in the mounting portion main body 244a along the axial direction. The second attachment portion 244b can be disposed to face the first attachment portion 242b. The second attachment portion 244b is disposed in parallel with the first attachment portion 242b. The second attachment portion 244b has a length in the axial direction that is larger than the attachment portion main body 244a, and is formed substantially the same length as the first attachment portion 242b. Therefore, the second attachment portion 244b is formed to protrude from the back surface and the front surface of the attachment portion main body 244a. A second dust cover 224b of a dust cover 224 made of a plate material is fixed to both ends of the second mounting portion 244b in the axial direction. The second dust cover 224b covers both ends of the second mounting portion 244b in the axial direction. The configuration of the outer peripheral side of the mounting portion main body 244a is substantially the same as that of the first embodiment.

The second mounting portion 244b includes a rectangular first housing portion 244c that has the second sliding portion 252 The pressing direction P (the upper and lower directions in FIG. 14 ) that is pressed toward the first sliding portion 250 is movably accommodated; and the second housing portion 244 d has the pressing member 294 described below in the adjustment direction A orthogonal to the pressing direction ( Referring to Fig. 14), it is movably accommodated. The first housing portion 244c and the second housing portion 244d are formed over the entire length of the second mounting portion 244b in the axial direction. The length of the second housing portion 244d in the adjustment direction A is longer than the first housing portion 244c.

The sprocket main body 246 has the same configuration as that of the first embodiment, and is attached to the locating wheel mounting portion 244 by the positioning member 64 attached to the first groove 44f and the tool-free stopper member 28 attached to the second groove 44g. The outer peripheral surface is positioned and stopped in the axial direction parallel to the central axis of rotation C, and rotates integrally with the sprocket mounting portion 244.

<sliding mechanism>

As shown in FIGS. 13 and 14, the sliding mechanism 216 includes a plurality of (for example, four) sliding portions 248 and a retainer 256. The plurality of sliding portions 248 are disposed at substantially rectangular corners. Further, in FIG. 14, the holder 256 is not shown. Each of the plurality of sliding portions 248 includes a first sliding portion 250, a second sliding portion 252, and at least one rolling element 54. The first sliding portion 250 is integrally attached to the crank member 212. The second sliding portion 252 is movably attached to the sprocket member 214 in the pressing direction P. Similarly to the first embodiment, the first sliding portion 250 is integrally attached to the first mounting recess portion 242d of the first mounting portion 242b provided in the support portion 242 of the crank member 212, for example. The inner side surface 250a of the first sliding portion 250 is engaged with the first mounting recess portion 242d. The outer side surface 250b of the first sliding portion 250 has an inner guiding groove 250c that guides the rolling element 254 in a circular arc shape.

As shown in FIG. 14 , the second sliding portion 252 is movably provided in the first housing portion 244 c of the second mounting portion 244 b provided in the sprocket mounting portion 244 in the pressing direction P (the vertical direction in FIG. 14 ). The second sliding portion 252 constitutes the sliding portion 248 and also constitutes the loosening prevention mechanism 222. The inner side surface 252b of the second sliding portion 252 has an outer side guiding groove 252c having a circular arc-shaped cross section that guides the rolling elements 54. The second sliding portion 252 restricts the direction orthogonal to the pressing direction P and the adjustment direction A by the second dust cover 224b fixed to both ends of the second mounting portion 244b (paper of FIG. 14) The movement of the face orthogonal direction).

At least one rolling element 54 is disposed between the first sliding portion 250 and the second sliding portion 252. In the second embodiment, the rolling elements 54 are also made of, for example, steel beads, and two sliding portions 248 are provided at intervals along the axial direction parallel to the central axis of rotation C. The rolling elements 54 may also be needle-shaped or roll-shaped.

As shown in FIG. 13, the retainer 256 is a substantially rectangular annular member disposed between the support portion 242 and the sprocket mounting portion 244. The holder 256 holds one set of two rolling elements 54 in the axial direction at one time, and holds the four sets of rolling elements 254 at intervals in the circumferential direction.

Here, the first attachment recess 242c is formed to be inclined with respect to a plane parallel to the rotation central axis C, and the first sliding portion 250 is also formed obliquely. Therefore, when the first sliding portion 250 is followed by the first mounting recess portion 242c, the first sliding portion 250 is less likely to scrape off the adhesive. Thereby, even if the first sliding portion 250 is attached to the first mounting recess portion 242c, the operation of wiping off the scraping agent can be reduced.

<Loose prevention mechanism>

The loosening prevention mechanism 222 includes a first cam portion 252d, a pressing member 294, and an adjustment member 298 which are provided in one of the first sliding portion 250 and the second sliding portion 252. The pressing member 294 includes the second cam portion 294a that is in contact with the first cam portion 252d, and one of the first sliding portion 250 and the second sliding portion 252 can be oriented toward the first sliding portion 250 and the second sliding portion 252. The other one presses. In the present embodiment, the first cam portion 252d is provided in the second sliding portion 252, and the second cam portion 294a is provided in the pressing member 294. The pressing member 294 is movable in the adjustment direction A in the second housing portion 244d. The pressing member 294 is formed to have the same length as the length of the second housing portion 244d in the axial direction parallel to the central axis of rotation. The pressing member 294 includes a female screw portion 294c to which the adjustment member 298 is screwed.

The first cam portion 252d has a first inclined surface 252e, and the second cam portion 294a has a second inclined surface 294b that is in contact with the first inclined surface 252e. The first inclined surface 252e and the second inclined surface 294b are inclined so as to intersect the adjustment direction A. In the embodiment, the first inclined surface The 252e and the second inclined surface 294b are inclined downward from the upstream side in the driving rotational direction DD of the crank assembly 210 toward the downstream side and on the left side in FIG. Further, the first inclined surface 252e and the second inclined surface 294b may be inclined upward from the upstream side in the driving rotational direction DD of the crank assembly 210 toward the downstream side in the left side in FIG. Further, in the first cam portion 252d and the second cam portion 294a, if one cam portion has an inclined surface, the other cam portion can be formed in line contact with the inclined surface. For example, the other cam portion may include at least one protrusion that protrudes in an arc shape and is in line contact with the inclined surface line.

The adjustment member 298 displaces the pressing member 294 such that the second cam portion 294a relatively moves relative to the first cam portion 252d. The adjustment member 298 includes a screw portion 298a screwed to the female screw portion 294c of the pressing member 294, a mounting shaft portion 298b having a smaller diameter than the screw portion 298a, and an annular groove 298c formed in the mounting shaft portion 298b. The adjustment member 298 is rotatably supported by the second attachment portion 244b by the first hole 244e and the second hole 244f formed through the second housing portion 244d. The adjustment member 298 is stopped relative to the second attachment portion 244b by a buckle 232 (for example, an E-shaped buckle) attached to the annular groove 298c. The end portion of the adjustment member 298 on the side of the first hole 244e has a tool engagement hole 298d formed to be engageable with a hexagonal wrench.

<dust cover>

As described above, the dust cover 224 includes a plate-shaped first dust cover 224a that covers each of the first attachment portions 242b, and a plate-shaped second dust cover 224b that covers each of the second attachment portions 244b. The first dust cover 224a is fixed to both end faces of the first attachment portion 242b by, for example, two screw members. The second dust cover 224b is fixed to both end faces of the second attachment portion 244b by, for example, three screw members.

When the sprocket attachment portion 244 is loosened with respect to the support portion 242, the adjustment member 298 is rotated in the direction in which the screw is retracted (counterclockwise in the case of the right-handed thread), and the pressing member 294 is moved to the right in FIG. . Thereby, the weight of the sliding mechanism 16 in the radial direction and the circumferential direction can be adjusted, thereby preventing looseness.

<Modification of Second Embodiment>

In the following description, the configuration corresponding to the configuration of the modification of the second embodiment is the same as the configuration of the second embodiment, with the same three-digit symbol as the second embodiment. , expressed by the same symbol.

As shown in Fig. 15, the loosening prevention mechanism 322 of the crank assembly 310 according to the modification of the second embodiment is different from the second embodiment. The change preventing mechanism 322 does not press the second sliding portion 252 directly by the adjusting member 398, but presses the second sliding portion 252 via the biasing member 334.

The first housing portion 344c is formed in a substantially rectangular shape. The second housing portion 344d has a screw hole 344e on the downstream side in the driving rotation direction DD. The pressing member 394 includes a second cam portion 394a having a second inclined surface 394b of the same configuration as that of the second embodiment. The pressing member 394 includes a circular support recess 394c that rotatably supports the adjustment member 398. The urging member 334 is disposed inside the support recess 394c in a compressed state. The adjustment member 398 displaces the pressing member 394 via the biasing member 334 such that the second cam portion 394a relatively moves relative to the first cam portion 252d. The adjustment member 398 includes a screw portion 398a screwed to the screw hole 344e, and a support shaft 398b having a diameter smaller than the screw portion 398a and rotatably supported by the support recess 394c. Further, the adjustment member 398 includes a spring projection 398c for attaching the biasing member 334, and a tool engagement portion 398d for engaging a tool such as a hexagonal wrench. The tool engagement portion 398d is formed on the end surface of the screw portion 398a. The urging member 334 includes a coil spring disposed between the adjustment member 398 and the bottom of the support recess 394c in a compressed state on the outer peripheral side of the spring projection 398c.

In the loosening prevention mechanism 322 having such a configuration, the second sliding portion 252 is biased by the biasing member 334 as in the first embodiment. Therefore, even if the sliding mechanism 316 is loosened due to wear, it can be automatically Reduce the ease.

<Other Embodiments>

The embodiment of the present invention has been described above, but the present invention is not limited to the embodiment described above, and various modifications can be made without departing from the spirit and scope of the invention. In particular, the plurality of embodiments and variations described in the present specification may be arbitrarily combined as needed.

(a) In the first embodiment, the crankshaft 20 and the tool-free stopper member 28 are provided, but these may not be provided, and at least one of them may be provided.

(b) In the first embodiment and the second embodiment, the rolling element is used between the support portion and the sliding portion to reduce the sliding resistance. However, the present invention is not limited thereto. The support portion and the sliding portion may be directly coupled to each other so as to be slidable and integrally rotatable. For example, the support portion may be engaged with the sliding portion spline. In this case, a coating film for reducing the sliding resistance such as a lubricating oil or a fluorine compound film or a hard carbon film may be formed on at least one of the sliding portions of the support portion and the sliding portion.

(e) In the above two embodiments, the front sprocket member is one piece, but the present invention is not limited thereto. The invention may also be applied to a crank assembly in which the front sprocket member is a plurality of pieces (e.g., 2 or 3 pieces). In particular, in this case, it is possible to alleviate the extent to which the chain generated by the front sprocket member and the rear sprocket member with the minimum number of teeth meshing or the maximum number of teeth meshing with each other is obliquely arranged.

(f) In the above two embodiments, the thickness of each of the sprocket members in the direction of the rotation center axis C (axial direction) is the same, but the present invention is not limited thereto. For example, the total number of sprocket teeth may be an even number, and the first sprocket teeth and the second sprocket teeth may be alternately arranged in the circumferential direction, and the first sprocket teeth are engaged with the links outside the chain but not Engaged in the inner link of the chain and having a first axial thickness, the second sprocket can be engaged with the inner link of the chain and have a second axial thickness that is smaller than the first thickness. In such a configuration, the chain is less likely to fall off from the sprocket member during the rotational driving.

(g) The circumferential length of the radial front end portion of the sprocket tooth may be made larger than the circumferential length of the radially intermediate portion of the sprocket member tooth in contact with the roller of the chain when the rotation is driven. In such a configuration, the chain is less likely to fall off from the sprocket member during the rotational driving.

22‧‧‧Loose prevention mechanism

42‧‧‧Support Department

42f‧‧‧1st bracket

42g‧‧‧鸠尾槽

45‧‧‧Base member

60‧‧‧Contact members

60a‧‧‧sliding trough

60b‧‧‧ recess

62‧‧‧ Pressing adjustment member

66‧‧‧Flexible components

66a‧‧1st end

68‧‧‧Rotary components

70‧‧‧Action components

72‧‧‧Fixed components

74‧‧‧ Cover member

78‧‧‧screw components

C‧‧‧Rotation center axis

Claims (27)

A bicycle crank assembly comprising: a crank member; a sprocket member having a central axis of rotation; and a sliding mechanism coupling the sprocket member and the crank member to be axially slidable parallel to the central axis of rotation; a loosening prevention mechanism that prevents looseness of the crank member and the sprocket member; and the loosening prevention mechanism includes an elastic member. The bicycle crank assembly of claim 1, wherein the sliding mechanism comprises: a first sliding portion integrally mounted with the crank member; a second sliding portion integrally mounted with the sprocket member; and at least one rolling body, The arrangement is between the first sliding portion and the second sliding portion. The bicycle crank assembly of claim 2, wherein the loosening prevention mechanism comprises: a contact member mounted to one of the crank member and the sprocket member; and a pressing adjustment member mounted to the crank member and the sprocket The other of the members, and comprising the above elastic member; and the elastic member is in contact with the contact member. The bicycle crank assembly according to claim 2, wherein the elastic member has a first end portion and a second end portion, and the first end portion of the elastic member is in contact with the contact member, and the pressing adjustment member includes the elastic member a rotating member that engages at the end portion and an operating member that rotates the rotating member. The bicycle crank assembly of claim 4, wherein the other of the crank member and the sprocket member is formed with a first threaded portion, and the operating member includes a second threaded portion that is screwed to the first threaded portion. A bicycle crank assembly according to any one of claims 3 to 5, wherein said contact member is a member made of a synthetic resin extending in said axial direction. The bicycle crank assembly of claim 6, wherein the contact member has a sliding groove extending along the axial direction and sliding the first end portion of the elastic member. The bicycle crank assembly according to any one of claims 1 to 5, wherein the contact member is detachably fixed to one of the crank member and the sprocket member. A bicycle crank assembly comprising: a crank member; a sprocket member having a central axis of rotation; and a sliding mechanism including slidably coupling the sprocket member and the crank member in an axial direction parallel to the central axis of rotation a plurality of sliding portions; and a plurality of dust covers attached to each of the plurality of sliding portions. The bicycle crank assembly of claim 9, wherein each of the plurality of sliding portions includes: a first sliding portion integrally mounted with the crank member; and a second sliding portion integrally mounted with the sprocket member; At least one rolling element is disposed between the first sliding portion and the second sliding portion. The bicycle crank assembly of claim 10, wherein the plurality of rolling elements are provided, and each of the plurality of rolling elements is disposed between the first sliding portion and the second sliding portion, and each of the plurality of sliding portions Further, the holder further includes a holder that holds at least the plurality of rolling elements at intervals in the circumferential direction. The bicycle crank assembly according to any one of claims 9 to 11, wherein each of the plurality of dust covers covers a gap between the first sliding portion and the second sliding portion. A bicycle crank assembly comprising: a crank member; a sprocket member having a central axis of rotation; and a sliding mechanism coupling the sprocket member and the crank member to be axially slidable parallel to the central axis of rotation; a sliding stroke amount adjusting mechanism capable of adjusting a sliding stroke of the sprocket member with respect to the crank member; and the sliding stroke amount adjusting mechanism includes an abutting member attached to the crank member and the sprocket member One of the above, and when the sliding mechanism slides, contacts the other of the crank member and the sprocket member, and the abutting member includes contact with the other of the crank member and the sprocket member The abutting portion and the shaft portion having a diameter smaller than the abutting portion. The bicycle crank assembly according to claim 13, wherein the sliding stroke amount adjustment mechanism includes at least one of a first slip stroke amount adjustment unit and a second slide stroke amount adjustment unit, and the first slide stroke amount adjustment unit is capable of facing the edge The amount of sliding stroke of the first axial direction in which the central axis of rotation is separated from the crank member is adjusted, and the second sliding stroke amount adjusting unit can adjust the amount of sliding stroke in the second axial direction opposite to the first axial direction. . The bicycle crank assembly according to claim 14, wherein the second sliding stroke amount adjusting portion is disposed on the opposite side of the first sliding stroke amount adjusting portion with respect to the rotation center axis. The bicycle crank assembly according to any one of claims 13 to 15, wherein the sliding stroke amount adjusting mechanism further includes a cushioning member attached to the other of the crank member and the sprocket member, and the cushioning member is coupled to the cushion member The abutting portion of the connecting member is in contact. A bicycle crank assembly comprising: a crank member; a sprocket member having a central axis of rotation; a sliding mechanism including a sliding portion, wherein the sprocket member and the crank member are coupled to be slidable in an axial direction parallel to the central axis of rotation; and a loosening prevention mechanism And provided in the sliding portion to prevent looseness of the crank member and the sprocket member. The bicycle crank assembly of claim 17, wherein the sliding mechanism comprises a plurality of sliding portions. The bicycle crank assembly of claim 18, wherein the loosening prevention mechanism is provided in each of the plurality of sliding portions. The bicycle crank assembly according to any one of claims 17 to 19, wherein the sliding portion includes: a first sliding portion integrally mounted with the crank member; and a second sliding portion integrally mounted with the sprocket member; And a plurality of rolling elements disposed between the first sliding portion and the second sliding portion; and the loosening preventing mechanism is provided at at least one of the first sliding portion and the second sliding portion. The bicycle crank assembly of any one of claims 17 to 19, wherein the sliding mechanism further comprises a retainer that holds the plurality of rolling elements at intervals in the circumferential direction. The bicycle crank assembly of claim 20, wherein the loosening preventing mechanism includes: a first cam portion provided in one of the first sliding portion and the second sliding portion; and a pressing member including the first cam The second cam portion that is in contact with the second one of the first sliding portion and the second sliding portion is pressed toward the other of the first sliding portion and the second sliding portion; and an adjusting member Displace the pressing member to make the second cam portion relative to The first cam portion moves relative to each other. The bicycle crank assembly of claim 22, wherein the first cam portion has a first inclined surface, and the second cam portion has a second inclined surface that contacts the first inclined surface. The bicycle crank assembly of claim 22, wherein the pressing member includes a first threaded portion formed along a displacement direction of the pressing member, and the adjusting member includes a second threaded portion that is screwed to the first threaded portion. The bicycle crank assembly of claim 24, wherein the first threaded portion is a female threaded portion, and the second threaded portion is a male threaded portion. The bicycle crank assembly of claim 20, wherein the loosening preventing mechanism includes: a first cam portion provided in one of the first sliding portion and the second sliding portion; and a pressing member including the first cam a second cam portion that is in contact with the second pressing portion, and one of the first sliding portion and the second sliding portion is pressed toward the other of the first sliding portion and the second sliding portion; and an elastic member The pressing member is biased in a direction in which the second cam portion relatively moves with respect to the first cam portion. The bicycle crank assembly of claim 26, wherein the first cam portion has a first inclined surface, and the second cam portion has a second inclined surface that contacts the first inclined surface.