JP2016196236A - Crank assembly for bicycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deterioration of the driving efficiency in a crank assembly in which a sprocket member is movable in a rotation axis direction.SOLUTION: A crank assembly 10 for a bicycle includes: a crank member 12; a sprocket member 14; a slide mechanism 16; and a backlash prevention mechanism 22. The sprocket member 14 has a rotation center axis C. The slide mechanism 16 connects the sprocket member 14 with the crank member 12 so that the sprocket member 14 and the crank member 12 may slide in a rotation center axis C direction and integrally rotate. The backlash prevention mechanism 22 prevents backlash of the crank member 12 and the sprocket member 14. The backlash prevention mechanism 22 includes an elastic member 66.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a crank assembly, and more particularly, to a bicycle crank assembly having a rotation center shaft.

  2. Description of the Related Art Conventionally, in a bicycle on which a single front sprocket and a plurality of rear sprockets are mounted, a gear that is shifted by a rear derailleur is known. When a speed change operation is performed by the rear derailleur, the chain may be disposed obliquely with respect to the front sprocket surface between the front sprocket and the rear sprocket. If the chain is disposed obliquely between the front sprocket and the rear sprocket, the chain may come off from the front sprocket. Therefore, a bicycle crank assembly is conventionally known in which the front sprocket is movable in an axial direction parallel to the rotation center axis so that the chain is difficult to come off, and the chain is hardly arranged obliquely (for example, Patent Document 1).

  In the crank assembly of Patent Document 1, a support shaft extending in the axial direction parallel to the rotation center axis of the front sprocket is provided at the tips of a plurality of arms provided at one end of a crank arm for attaching the front sprocket. A sprocket member is supported on the support shaft so as to be movable in the axial direction.

  Further, Patent Document 1 discloses a crank assembly in which a cylindrical member having a plurality of grooves extending in the axial direction at intervals in the circumferential direction is arranged at one end of the crank arm. End portions of a plurality of sprocket arms that extend radially inward in the radial direction of the front sprocket are supported by the groove portion of the cylindrical member so as to be movable in the axial direction.

US Patent Application Publication No. 2013/0008282

  In the crank assembly of Patent Document 1, since the front sprocket is supported by the crank arm or the arm that extends radially from the front sprocket, the strength of the portion that supports the front sprocket becomes insufficient, and the driving efficiency may be reduced.

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

  A crank assembly for a bicycle according to the present invention includes a crank member, a sprocket member, a sliding mechanism, and a rattling prevention mechanism. The sprocket member has a rotation center axis. The sliding mechanism connects the sprocket member and the crank member so as to be slidable in an axial direction parallel to the rotation center axis. The rattling prevention mechanism prevents rattling between the crank member and the sprocket member. The rattling prevention mechanism includes an elastic member.

  In this bicycle crank assembly, when the crank member rotates about the rotation center axis, the sprocket member also rotates about the rotation center axis. At this time, if the chain is disposed obliquely between the front sprocket and the rear sprocket, an axial force parallel to the rotation center axis acts on the sprocket member due to the tension of the chain. In this case, the sliding mechanism moves the sprocket member in the axial direction with respect to the crank member, and the degree to which the chain is disposed obliquely between the front sprocket and the rear sprocket is reduced. At the time of the sliding, one of the sprocket member and the crank member is urged toward the other by the elastic member of the rattling prevention mechanism to prevent the sprocket member and the crank member from rattling. As a result, it is possible to prevent a decrease in driving efficiency due to rattling.

  The sliding mechanism includes a first sliding portion attached integrally with the crank member, a second sliding portion attached integrally with the sprocket member, and the first sliding portion and the second sliding portion. And at least one rolling element to be disposed. In this case, since the sprocket member slides with respect to the crank member via the rolling elements, the sliding resistance is reduced and the sprocket member slides smoothly.

  The rattling prevention mechanism includes a contact member that is attached to one of the crank member and the sprocket member, and a pressure adjusting member that is attached to the other of the crank member and the sprocket member and includes an elastic member, and the elastic member is attached to the contact member. Contact. In this case, by adjusting the elastic force of the elastic member, rattling can be prevented even if the gap between the first sliding portion and the second sliding portion changes due to wear or the like.

  The elastic member may have a first end and a second end, and the first end of the elastic member may contact the contact member. The pressing adjustment member may include a rotating member that engages with the second end of the elastic member and an operation member that rotates the rotating member. In this case, the elastic force can be easily adjusted by moving the second end of the elastic member by rotating the rotation member with the operating member.

  A first screw portion may be formed on the other of the crank member and the sprocket member, and the operating member may have a second screw portion that is screwed into the first screw portion. In this case, the elastic force can be finely adjusted by turning the second screw portion.

  The contact member may be a synthetic resin member extending along an axial direction parallel to the rotation center axis. 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 move smoothly.

  The contact member may have a sliding groove that extends along an axial direction parallel to the rotation center axis and in which the first end of the elastic member slides. 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 reliably guided in the axial direction.

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

  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 rotation center axis. The sliding mechanism includes a plurality of sliding portions that slidably connect the sprocket member and the crank member in an axial direction parallel to the rotation center axis. The plurality of dust covers are attached to each of the plurality of sliding portions.

  In this bicycle crank assembly, when the crank member rotates about the rotation center axis, the sprocket member also rotates about the rotation center axis. At this time, if the chain is disposed obliquely between the front sprocket and the rear sprocket, an axial force parallel to the rotation center axis acts on the sprocket member due to the tension of the chain. In this case, the sliding mechanism moves the sprocket member in the axial direction with respect to the crank member, and the degree to which the chain is disposed obliquely between the front sprocket and the rear sprocket is reduced. A plurality of sliding portions of this sliding mechanism are not covered all at once, but are individually covered by a plurality of dust covers. For this reason, the penetration | invasion of the liquid and foreign material to a sliding part can be prevented efficiently. As a result, it is possible to prevent a decrease in driving efficiency due to intrusion of liquid or foreign matter. Furthermore, since the plurality of sliding portions of the sliding mechanism are not collectively covered but individually covered by the plurality of dust covers, the dust covers can be individually effective.

  Each of the plurality of sliding portions includes a first sliding portion attached integrally with the crank member, a second sliding portion attached integrally with the sprocket member, a first sliding portion and a second sliding portion. And at least one rolling element disposed between the two. In this case, since the first sliding portion and the second sliding portion are in rolling contact with the rolling element, the sliding resistance is reduced. For this reason, the sprocket member can move quickly and smoothly in the axial direction parallel to the rotation center axis with respect to the crank member.

  A plurality of rolling elements may be provided. 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 cage that holds at least 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, the plurality of rolling elements roll efficiently.

  Each of the plurality of dust covers may cover a 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 rotation center axis, 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 rotation center axis. The sliding mechanism connects the sprocket member and the crank member so as to be slidable in an axial direction parallel to the rotation center axis. The sliding stroke amount adjusting mechanism can adjust the sliding stroke of the sprocket member relative to the crank member.

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

  In this bicycle crank assembly, when the crank member rotates about the rotation center axis, the sprocket member also rotates about the rotation center axis. At this time, the chain is disposed obliquely between the front sprocket and the rear sprocket, and an axial force parallel to the rotation center axis may act on the sprocket member due to the tension of the chain. In this case, the sliding mechanism moves the sprocket member in the axial direction with respect to the crank member, and the degree to which the chain is disposed obliquely between the front sprocket and the rear sprocket is reduced. The sliding stroke of the sprocket member relative to the crank member can be adjusted by the sliding stroke amount adjusting mechanism. Specifically, the sliding stroke amount can be adjusted by arranging, for example, the shaft portion of the contact member so as to be positioned at an arbitrary position in the axial direction. For this reason, the interference between the chain and the frame can be prevented by adjusting the sliding stroke amount according to the frame of the bicycle. As a result, it is possible to prevent a decrease in drive efficiency due to contact between the chain and the frame.

  The sliding stroke amount adjustment mechanism may include at least one of a first sliding stroke amount adjustment unit and a second sliding stroke amount adjustment unit. The first sliding stroke amount adjusting unit may be capable of adjusting a sliding stroke amount 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 be capable of adjusting the sliding stroke amount in the second axial direction opposite to the first axial direction. In this case, the amount of sliding stroke of the chain in both axial directions parallel to the rotation center axis can be adjusted. Therefore, even if the chain is adjusted so as not to contact the frame, it is easy to ensure the amount of stroke of the sprocket.

  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. In this case, the first sliding stroke amount adjusting unit and the second sliding stroke amount adjusting unit can be arranged with good balance.

  The sliding stroke amount adjusting mechanism may further include a buffer member attached to the other of the crank member and the sprocket member. The buffer member may contact the contact portion of the contact member. In this case, the contact member does not directly contact the other of the crank member and the sprocket member, but contacts the buffer member, so that the impact at the time of contact can be reduced.

  According to still another aspect of the present invention, a bicycle crank assembly includes a crank member, a sprocket member, a sliding mechanism, and a rattling prevention mechanism. The sprocket member has a rotation center axis. The sliding mechanism has a sliding portion that connects the sprocket member and the crank member so as to be slidable in an axial direction parallel to the rotation center axis. The rattling prevention mechanism is provided at the sliding portion and prevents rattling between the crank member and the sprocket member.

  In this bicycle crank assembly, when the crank member rotates about the rotation center axis, the sprocket member also rotates about the rotation center axis. At this time, the chain is disposed obliquely between the front sprocket and the rear sprocket, and an axial force parallel to the rotation center axis may act on the sprocket member due to the tension of the chain. In this case, the sliding mechanism moves the sprocket member in the axial direction parallel to the rotation center axis with respect to the crank member, and the degree of the diagonal arrangement of the chain between the front sprocket and the rear sprocket is reduced. A rattling prevention mechanism is provided at the sliding portion where rattling occurs during this sliding, so that even if the sliding portion is worn, rattling between the sprocket member and the crank member can be reliably prevented. As a result, it is possible to prevent a decrease in driving efficiency due to rattling.

  The sliding mechanism may have a plurality of sliding portions. In this case, since the sliding mechanism has a plurality of sliding portions, the sprocket member can be smoothly slid relative to the crank member.

  The rattling prevention mechanism may be provided in each of the plurality of sliding portions. In this case, rattling can be prevented according to wear of each sliding part.

  The sliding portion includes a first sliding portion attached integrally with the crank member, a second sliding portion attached integrally with the sprocket member, and the first sliding portion and the second sliding portion. You may have a plurality of rolling elements arranged. The rattling prevention mechanism may be provided in at least one of the first sliding portion and the second sliding portion. In this case, rattling of each sliding portion can be individually prevented by moving at least one of the first sliding portion and the second sliding portion toward the other.

  The sliding mechanism may further include a cage 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, the plurality of rolling elements roll efficiently.

  The rattling prevention mechanism may include a first cam portion, a pressing member, and an adjustment member. The first cam portion may be provided on one of the first sliding portion and the second sliding portion. The pressing member has a second cam portion that contacts the first cam portion, and presses one of the first sliding portion and the second sliding portion toward the other of the first sliding portion and the second sliding portion. It may be possible. The adjustment member may displace the pressing member so that the second cam portion moves relative to the first cam portion. In this case, when the pressing member is displaced by the adjusting member, the second cam portion moves relative to the first cam portion, and the pressing member moves one of the first sliding portion and the second sliding portion to the first. Press toward the other of the first sliding portion and the second sliding portion. Thereby, rattling 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 is displaced between the first sliding portion and the second sliding portion. The force for pressing the other can be adjusted.

  The pressing member may have a first screw portion formed along the displacement direction of the pressing member, and the adjustment member may have a second screw portion that is screwed into the first screw portion. In this case, when the adjustment member is turned, 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 configured in a rod shape, and a screw hole may be provided in the pressing member, so that the adjustment structure can be reduced in size.

  The rattling prevention mechanism may include a first cam portion, a pressing member, and an elastic member. The first cam portion may be provided on one of the first sliding portion and the second sliding portion. The pressing member has a second cam portion that contacts the first cam portion, and presses one of the first sliding portion and the second sliding portion toward the other of the first sliding portion and the second sliding portion. It may be possible. The elastic member may bias the pressing member in a direction in which the second cam portion moves relative to the first cam portion. In this case, the elastic member attaches the pressing member so that the pressing member presses one of the first sliding portion and the second sliding portion toward the other of the first sliding portion and the second sliding portion. Rush. Thereby, rattling 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 by the urging member in a direction intersecting the first inclined surface, one of the first sliding portion and the second sliding portion becomes the first sliding portion and the second sliding portion. The force with which one of the two approaches and the other presses the other can be adjusted.

  In the crank assembly in which the sprocket member is movable in the direction of the rotation axis, it is possible to prevent a decrease in drive efficiency.

1 is a perspective rear view of a bicycle crank assembly according to a first embodiment of the present invention. FIG. The front view of the crank assembly for bicycles. The disassembled perspective view of the structure of a part of bicycle crank assembly. The disassembled perspective view of the remaining structure of the crank assembly for bicycles. The rear enlarged view of the crank assembly of the state which removed the dust cover. Sectional drawing cut | disconnected by the cutting | disconnection line VI-VI of FIG. Sectional drawing cut | disconnected by the cutting line VII-VII of FIG. The perspective view of a rattling prevention mechanism. The top view of a rattling prevention mechanism. The disassembled perspective view of a rattling prevention mechanism. Sectional drawing equivalent to FIG. 7 of the modification of 1st Embodiment. The front view of the crank assembly for bicycles by a 2nd embodiment of the present invention. The rear view equivalent to FIG. 6 of 2nd Embodiment. The cross-sectional enlarged view of the rattling prevention mechanism of 2nd Embodiment. The cross-sectional enlarged view equivalent to FIG. 14 of the rattling prevention mechanism of the modification of 2nd 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 rotation center axis C, and A sliding mechanism 16. The crank assembly 10 includes a crankshaft 20, a rattling prevention mechanism 22, a plurality of dust covers 24, a sliding stroke amount adjusting mechanism 26, a tool unnecessary retaining member 28, a sliding stroke amount limiting mechanism 30, Is further provided. If necessary, the crankshaft 20 and the toolless retaining member 28 may be selectively omitted. The sliding mechanism 16 connects the sprocket member 14 and the crank member 12 so as to be slidable in the direction of the rotation center axis C and to be integrally rotatable. The rattling prevention mechanism 22 prevents rattling between the crank member 12 and the sprocket member 14. The plurality of dust covers 24 are attached to the sliding mechanism 16 and prevent foreign matter from entering the sliding mechanism 16. The sliding stroke amount adjusting mechanism 26 can adjust the sliding stroke amount of the sprocket member 14 relative to the crank member 12. The tool unnecessary retaining member 28 prevents a sprocket main body 46 (to be described later) of the sprocket member 14 from coming off from the sprocket mounting portion 44 without using a tool.

<Crank member>
The crank member 12 is, for example, a light metal member such as aluminum. The crank member 12 includes an arm portion 40 and a support portion 42 that can rotate integrally around the arm portion 40 and the rotation center axis C. As shown in FIG. 3, the arm portion 40 constitutes a crank arm extending in the radial direction of the rotation center axis C. The arm portion 40 has a shaft mounting hole 40a that connects the crankshaft 20 so as to be integrally rotatable at one end. 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 mounting hole 40a, a support protrusion 42 is formed so as to project annularly, for example, so as to be connected to be integrally rotatable by press-fitting or bonding. For example, serrations are formed in the shaft mounting hole 40a and the connecting projection 40c.

  The support portion 42 supports the sprocket member 14 via the sliding mechanism 16 so as to be integrally rotatable and slidable. As shown in FIGS. 4, 5, and 6, the support portion 42 includes a support portion main body 42 a formed in a substantially square shape, and an axial direction parallel to the rotation center axis C on the outer peripheral surface of the support portion main body 42 a. A plurality of (for example, four) first attachment portions 42b formed integrally. The support portion main body 42a has a connection hole 42c connected to the connection protrusion 40c of the arm portion 40 so as to be integrally rotatable. The first attachment portion 42b is longer in the axial direction 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 has a plurality of (for example, four) first attachment recesses 42d formed to be recessed in a flat U shape on the outer peripheral portion. 42 d of 1st attachment recessed parts are formed over the full length of the axial direction of the outer peripheral part of the 1st attachment part 42b. As shown in FIG. 4, the first mounting recess 42 d is formed so that the width gradually decreases from the back side to the front side (left side to right side in FIG. 4). Further, as shown in FIG. 6, the bottom portion 42e of the first mounting recess 42d is formed so that the depth gradually decreases from the back side to the front side (left side to right side in FIG. 6). As shown in FIG. 5, the bottom portion 42e of the first mounting recess 42d is arranged such that the angle α formed by the straight line L connecting the rotation center axis C and the center of the bottom portion 42e and the bottom portion 42e is an acute angle. Accordingly, 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 along the axial direction with respect to the crank member 12. In FIG. 5, the dust cover 24 is not shown.

<Sprocket member>
The sprocket member 14 is a metal member such as aluminum, titanium, or iron. The sprocket member 14 includes a sprocket mounting portion 44 and a sprocket body 46. The sprocket mounting portion 44 is supported by the support portion 42 through the sliding mechanism 16 so as to be integrally rotatable and slidable in an axial direction parallel to the rotation center axis C.

  As shown in FIGS. 3, 5, and 6, the sprocket mounting portion 44 has a cylindrical mounting portion main body 44 a and a plurality of sprocket mounting portions 44 that are integrally formed along the axial direction on the inner peripheral surface of the mounting portion main body 44 a. (For example, four) second attachment portions 44b. The second attachment portion 44b is disposed so as to face the first attachment portion 42b. The second attachment portion 44b is disposed in parallel with the first attachment portion 42b. The second mounting portion 44b is longer in the axial direction than the mounting portion main body 44a, and preferably has the same length as the first mounting portion 42b. Accordingly, the second attachment portion 44b is formed to protrude from the back surface and the front surface of the mounting portion main body 44a. The second attachment portion 44b has a plurality of (for example, four) second attachment recesses 44c formed to be recessed in a flat U shape on the inner peripheral portion. The second mounting recess 44c is formed over the entire axial length of the inner peripheral portion of the second mounting portion 44b. As shown in FIG. 3, the second mounting recess 44 c is formed so that the width gradually decreases from the back side to the front side (left side to right side in FIG. 3). Further, as shown in FIG. 6, the bottom 44d of the second mounting recess 44c is formed so that the depth gradually decreases from the back side to the front side (from the left side to the right side in FIG. 6).

  The mounting portion main body 44a has a connecting convex portion 44e on the outer peripheral surface for connecting the sprocket main body 46 so as to be integrally rotatable. Further, a first groove 44f (see FIG. 6) for mounting the positioning member 64 for positioning the sprocket body 46 in the axial direction and a second groove 44g for mounting the tool unnecessary retaining member 28 (see FIG. 6). And on the outer peripheral surface. The positioning member 64 is, for example, a C-type retaining ring.

  As shown in FIG. 3, the mounting portion main body 44a includes a pedestal 44h formed on the inner peripheral surface so as to protrude radially inward, and a base member 45 fixed to the pedestal 44h. The base member 45 is provided for mounting the rattling prevention mechanism 22 to the sprocket member 14. On the inner side surface of the base 44h, together with the base member 45, an internal thread portion 44i for fixing the rattling prevention mechanism 22 is formed. As shown in FIG. 8, the base member 45 is fixed to the base 44 h together with the rattling prevention mechanism 22. The base member 45 is fixed to the base 44h by a fixing member 72 described later of the rattling prevention mechanism 22. The base member 45 includes a base main body 45a and a nut member 45b attached to the base main body 45a. The base body 45a includes a base portion 45c and a bracket portion 45d formed orthogonal to the base portion 45c. The base portion 45c has a through hole 45e through which the fixing member 72 can pass and a positioning recess 45f positioned in 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 an operation member 70 described later can pass. The adjustment hole 45g and the through hole 45e are formed so that the center axis of the adjustment hole 45g and the center axis of the through hole 45e are not parallel to each other. The slit 45h is formed orthogonal to the adjustment hole 45g. A nut member 45b is detachably attached to the slit 45h. The nut member 45b has a female screw portion 45i. The female screw portion 45i is an example of a first screw portion. In addition, you may form an internal thread part directly in the adjustment hole 45g, without providing the nut member 45b. In this case, the slit 45h is unnecessary. However, if the nut member 45b is provided, only the nut member 45b can be replaced without replacing the base member 45 even if the female screw portion 45i is damaged.

  As shown in FIG. 3, the sprocket body 46 has a plurality of sprocket teeth 46 a on the outer periphery. The sprocket body 46 is connected to the sprocket mounting portion 44 so as to be integrally rotatable and detachable. The sprocket body 46 has a plurality of connecting recesses 46b that engage with the connecting protrusions 44e on the inner periphery of the sprocket body 46 so as to be rotatable and detachable. The sprocket main body 46 is axially positioned on the outer peripheral surface of the sprocket mounting portion 44 by the positioning member 64 mounted in the first groove 44f and the tool-less retaining member 28 mounted in the second groove 44g, and is prevented from slipping out. And rotate integrally with the sprocket mounting portion 44.

<Sliding mechanism>
As shown in FIGS. 4 to 6, the sliding mechanism 16 has a plurality of (for example, 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 cage 56. In the present embodiment, the first sliding portion 50 is attached integrally with the crank member 12, and the second sliding portion 52 is attached integrally with the sprocket member 14.

  The first sliding portion 50 is integrally attached to the first attachment recess 42d of the first attachment portion 42b provided on the support portion 42 of the crank member 12, for example, by bonding. The 1st sliding part 50 is arrange | positioned in parallel with the rotation center axis | shaft C, and is formed with the same length as the 1st attaching part 42b. As shown in FIG.4 and FIG.6, it has the inner surface 50a engaged with the 1st attachment recessed part 42d. Therefore, the inner side surface 50a of the first sliding portion 50 is formed so that the width gradually decreases from the back side toward the front side, and the thickness gradually decreases. The outer surface 50b of the first sliding portion 50 has an inner guide groove 50c having a circular arc cross section in which the rolling element 54 is guided.

  The second sliding portion 52 is integrally attached to the second mounting recess 44c of the second mounting portion 44b provided in the sprocket mounting portion 44 of the sprocket member 14, for example, by bonding. The second sliding portion 52 is disposed in parallel with the rotation center axis C and is formed with the same length as the second attachment portion 44b. As shown in FIGS. 4 and 6, the second sliding portion 52 has an outer surface 52 a that engages with the second mounting recess 44 c. Therefore, the outer side surface 52a of the second sliding part 52 is formed so that the width gradually decreases from the back side toward the front side, and the thickness gradually decreases. The inner side surface 52b of the second sliding portion 52 has an outer guide groove 52c having a circular cross section in which the rolling element 54 is guided.

  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, steel spheres. Two rolling elements 54 are provided at intervals along the axial direction parallel to the rotation center axis C on each sliding portion 48. The cage 56 holds the rolling elements 54 at an interval in the axial direction. The rolling element 54 may have a needle shape or a roller shape.

  As shown in FIG. 4, the retainer 56 has a first engagement protrusion 56 b that engages with the first attachment portion 42 b so as not to move in the axial direction at a first end 56 a in the circumferential direction. The retainer 56 has a second engagement protrusion 56d that engages with the second attachment portion 44b so as not to move in the axial direction at a second end 54c opposite to the first end 56a. Thereby, it attaches to the sliding part 48 of each holder | retainer 56 so that an axial movement is impossible.

  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 similarly inclined. Formed. For this reason, when the 1st sliding part 50 and the 2nd sliding part 52 are adhere | attached on the 1st attachment recessed part 42d and the 2nd attachment recessed part 44c, it can prevent that an adhesive agent leaks from an adhesion surface. Thereby, even if the first sliding portion 50 and the second sliding portion 52 are bonded to the first mounting recess 42d and the second mounting recess 44c, the work of wiping off the leaked adhesive can be reduced.

<Crankshaft>
The crankshaft 20 is a hollow cylindrical member in the first embodiment. The crankshaft 20 is connected to the crank member 12 so as to be integrally rotatable by press-fitting or bonding. However, the crankshaft 20 may be detachably attached to the crank member 12 by, for example, a screw member.

<Rattle prevention mechanism>
As shown in FIGS. 8 and 9, the rattling prevention mechanism 22 includes a contact member 60 and a pressing adjustment member 62 including an elastic member 66. The contact member 60 is attached to one of the crank member 12 and the sprocket member 14. The pressure adjusting 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 pressing adjustment member 62 is attached to the sprocket mounting portion 44 of the sprocket member 14. The arrangement of the contact member 60 and the pressure adjusting member 62 may be reversed.

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

  In FIG. 8, the first bracket 42f is indicated by a two-dot chain line. The first bracket 42f is formed with a dovetail groove 42g that is narrower than the bottom. The contact member 60 has an outer surface that can be engaged with the dovetail groove 42g. The contact member 60 is mounted in the dovetail groove 42g so that the position of the contact member 60 can be adjusted in the direction of the rotation center axis C and the displacement in the direction orthogonal to the rotation center axis C is restricted. The screw member 78 is screwed into the first bracket 42f and presses the contact member 60 toward the first end 66a, thereby fixing the contact member 60.

  The pressing adjustment member 62 urges the sprocket member 14 in the circumferential direction against the crank member 12 when the elastic member 66 presses the contact member 60. As a result, even when the sliding mechanism 16 is worn and rattling occurs, the sprocket member 14 does not rattle against the crank member 12.

  As shown in FIG. 10, the pressing adjustment member 62 preferably includes an elastic member 66, a rotation member 68, an operation member 70, a fixing member 72, and a cover member 74. The elastic member 66 is preferably a torsion coil spring having a first end portion 66a, a second end portion 66b, and a coil portion 66c provided between the first end portion 66a and the second end portion 66b. The first end portion 66 a that contacts the contact member 60 is curved in an arc shape, and the curved portion contacts the sliding groove 60 a of the contact member 60. Thereby, wear of the contact member 60 when the elastic member 66 slides with respect to the contact member 60 can be reduced. The second end portion 66b is bent in a direction away from the coil portion 66c. The elastic member 66 is mounted in a compressed state capable of generating an elastic force.

  The rotating member 68 is rotatably supported by the fixed member 72 on the base portion 45c. The rotating member 68 includes a ring portion 68a placed on the base portion 45c, and a contact portion 68b that protrudes outward from the outer peripheral portion of the ring portion 68a and can contact the operating member 70. The ring portion 68a has an engagement recess 68c with which the second end portion 66b of the elastic member 66 is engaged. The contact portion 68b is disposed so as to be able to face the bracket portion 45d and has a contact surface 68d with which the distal end portion of the operation member 70 comes into contact.

  The operating member 70 has a male screw portion 70a that is screwed into a nut member 45b attached to the bracket portion 45d. The male screw portion 70a is an example of a second screw portion. The operation member 70 has a tool engagement hole 70b that can be engaged with a tool such as a hexagon stick wrench at the base end. By rotating the operation member 70, the second end 66b of the elastic member 66 moves, and the spring force (elastic force) of the elastic member 66 changes. Thereby, the urging force of the rattling prevention mechanism 22 can be adjusted.

  The fixing member 72 is provided for fixing the rattling prevention mechanism 22 to the sprocket member 14 together with the base member 45. The fixing member 72 has a large-diameter head portion 72a, a shaft portion 72b, and a male screw portion 72c. The head 72a has a tool engaging portion 72d capable of engaging a tool such as a hexagonal bar wrench. The shaft portion 72b has an elastic member 66 wound around an outer peripheral surface and a rotating member 68 supported rotatably. The male screw portion 72c has a smaller diameter than the shaft portion 72b and is screwed into the female screw portion 44i of the base 44h.

  The cover member 74 is provided to prevent foreign matter from adhering to the elastic member 66. The cover member 74 is a thin-walled cylindrical member, and a notch portion 74a for passing the cover member 74 so that the first end portion 66a side of the elastic member 66 contacts the contact member 60 is formed at one end portion. The

  In the rattling prevention mechanism 22 configured as described above, the elastic member 66 applies an elastic force to the contact member 60 when the sprocket member 14 slides in the axial direction parallel to the rotation center axis C due to the tension of the chain. Therefore, rattling of the sprocket member 14 is less likely to occur. For this reason, it is possible to prevent a decrease in drive efficiency due to rattling.

<Dust cover>
The dust cover 24 is preferably an elastic member 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 part 50 and the second sliding part 52. As shown in FIGS. 2, 4, and 6, in the present embodiment, the dust cover 24 includes a plurality of first mounting portions 42 b of the support portion 42, a plurality of second mounting portions 44 b of the sprocket mounting portion 44, and It is formed in a bag shape having a space inside so as to cover the sliding portion 48. The dust cover 24 includes a first opening 24a, a second opening 24b, a first cover part 24c, a second cover part 24d, and a bellows part 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 part 24c is connected to the first opening 24a and is provided to cover the first attachment part 42b. The second cover portion 24d is connected to the second opening 24b and is provided to cover the second mounting portion 44b. The bellows part 24e connects the first cover part 24c and the second cover part 24d. The bellows portion 24e covers the sliding portion 48 by elastic deformation even when 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 so as to be inclined with respect to the facing portion.

  Each dust cover 24 is held by the support portion 42 and the sprocket mounting portion 44 by two holding members 76. The holding member 76 is formed by bending the spring wire into a rectangle and bending it along the first cover part 24c (or the second cover part 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 short side of the holding member 76 is hooked on the support portion 42 (or the sprocket mounting portion 44) on both sides in the circumferential direction of the first attachment portion 42b (or the second attachment portion 44b).

  Before assembling the sliding portions 48, the dust cover 24 is mounted in a state where the first opening 24a is expanded and the front and back sides are inverted inside the first attachment portion 42b. When the assembly of the sliding portion 48 is completed, the inverted dust cover 24 is returned to the original position, and the second opening 24b is expanded and attached to the outside of the second mounting portion 44b. As a result, each sliding portion 48 is covered by the dust cover 24.

  In the dust cover 24 having such a configuration, the plurality of sliding portions 48 are not collectively covered, but are individually covered by the plurality of dust covers 24. For this reason, the penetration | invasion of the liquid and foreign material to the sliding part 48 can be prevented efficiently. As a result, it is possible to prevent a decrease in driving efficiency due to 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 deteriorated dust cover 24 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 each sliding portion 48 can be reliably covered. Furthermore, since the dust cover 24 is made of an elastic body, the sprocket member 14 is positioned in the axial direction parallel to the desired rotation center axis C with respect to the support portion 42 (for example, as shown in FIG. Easy to return to the middle position of the sliding stroke).

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

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

  As shown in FIGS. 3, 4, and 7, the first sliding stroke amount adjustment unit 26 a is attached to one of the crank member 12 and the sprocket member 14, and when the sliding mechanism 16 slides, the crank member 12 and the sprocket are attached. A contact member 80 that contacts the other of the members 14 and a buffer member 82 attached to the other of the crank member 12 and the sprocket member 14 are provided. The buffer member 82 may be selectively omitted.

  In the present embodiment, the contact member 80 is attached to the sprocket mounting portion 44 of the sprocket member 14, and the buffer member 82 is provided on the support portion 42 of the crank member 12. The arrangement of the contact member 80 and the buffer member 82 may be reversed. As shown in FIG. 7, the contact member 80 includes a contact portion 80a that contacts the crank member 12, and a shaft portion 80b having a smaller diameter than the contact portion 80a. The shaft portion 80b has a male screw portion 80c and a tool engaging portion 80d. The male threaded portion 80c is screwed into a nut member 86 provided on a second bracket 84 formed to project radially inward from the inner peripheral surface of the mounting portion main body 44a of the sprocket mounting portion 44. The tool engaging portion 80d is located on the opposite side of the abutting portion 80a with respect to the shaft portion 80b, and has a non-circular hole in which a tool such as a hexagon stick wrench can be engaged. The second bracket 84 has an adjustment hole 84a through which the shaft portion 80b can pass, and a slit 84b into which the nut member 86 can be detachably attached. The nut member 86 has a female screw portion 86a that is screwed into the male screw portion 80c. In addition, you may form an internal thread part in the adjustment hole 84a, without providing the nut member 86. FIG. In this case, the slit 84b is unnecessary. However, if the nut member 86 is provided, it is only necessary to replace the nut member 86 without replacing the sprocket mounting portion 44 even if the female screw portion 86a is damaged.

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

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

<Sliding stroke limit mechanism>
As shown in FIG. 7, the sliding stroke amount limiting mechanism 30 sets the sliding stroke amount S in the second axial direction C2 opposite to the first axial direction C1 along the rotation center axis C of the sprocket member 14 to a fixed position. Restrict to. The sliding stroke amount limiting mechanism 30 is preferably arranged on the opposite side of the rotation center axis C from the first sliding stroke amount adjustment unit 26a. Therefore, it is preferable that the sliding stroke amount limiting mechanism 30 is arranged at an interval of approximately 180 degrees in the rotation direction from the first sliding stroke amount adjusting unit 26a.

  The sliding stroke amount limiting mechanism 30 includes a stopper 90 attached to one of the crank member 12 and the sprocket member 14, and a buffer member 82 attached to the other of the crank member 12 and the sprocket member 14 and contacting the stopper 90. . In the present embodiment, the stopper 90 is formed on the inner peripheral portion of the mounting portion main body 44a of the sprocket mounting portion 44 so as to protrude radially inward. The buffer member 82 is fixed to the fourth bracket 92 formed by protruding from the front side of the support portion 42 radially outward from the third bracket 88 by approximately 180 degrees in the circumferential direction, for example, by bonding.

<Tool-free retaining member>
As shown in FIG. 3, the tool-less retaining member 28 prevents the sprocket body 46 from coming off in the axial direction parallel to the rotation center axis C with respect to the sprocket mounting portion 44, and manually attaches the sprocket body 46 to the sprocket mounting portion 44. It is a member that can be detachably attached to. The tool unnecessary retaining member 28 includes a retaining ring 28a made of a metal wire having elasticity. The retaining ring 28a is formed, for example, by bending a metal wire. The retaining ring 28a has an annular spring portion 28b and a pair of operation handles 28c. The annular spring portion 28b can be mounted in the second groove 44g formed on the outer peripheral surface of the support portion 42. The annular spring portion 28b is formed in a smaller diameter in a free state than the mounting diameter of the second groove 44g. The pair of operation handles 28c extend radially outward from both ends of the annular spring portion 28b, and the diameter of the annular spring portion 28b can be manually increased from that of the second groove 44g. In the present embodiment, the annular spring portion 28b is disposed so that both ends overlap in the circumferential direction. The pair of operation handles 28c are formed to extend radially outward from both ends of the annular spring portion 28b that overlap, and to have a distal end that extends in a direction orthogonal to the direction in which the annular spring portion 28b extends curved in a circular shape. The tool-less retaining member 28 can be removed from the second groove 44g by gripping the pair of operation grips 28c with the thumb and forefinger in a direction in which the pair of operation grips 28c are brought close to expand the diameter of the annular spring portion 2b.

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

  When the position of the chain on the rear sprocket in the hub axial direction is displaced by the speed change operation, the sprocket main body 46 moves in the direction in which the chain is displaced in the axial direction parallel to the rotation center axis C by the tension acting on the chain. . For this reason, the state where the chain is disposed obliquely 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 sliding mechanism 16 of the present invention is configured to extend in the axial direction parallel to the rotation center axis C, the support portion 42 and the sprocket mounting portion 44 can maintain high strength.

  When the sprocket mounting portion 44 rattles against the support portion 42, the elastic member is rotated via the rotating member 68 by rotating the operation member 70 in the direction in which the screw advances (clockwise in the case of a right screw) with a hexagon stick wrench. The second end portion 66b of 66 is made elastic. Thereby, rattling of the sliding mechanism 16 can be prevented.

  When adjusting the movement amount of the sprocket mounting portion 44, the contact member 80 is adjusted by turning it with a hexagon stick wrench. When the abutting member 80 is rotated in the direction in which the screw advances (clockwise in the case of a right-hand screw), the stroke amount of the sprocket mounting portion 44 decreases, and when the abutting member 80 is rotated in the direction in which the screw returns, the sprocket mounting portion 44 Stroke amount increases. Accordingly, the stroke amount of the sprocket member 14 can be adjusted so that the chain and the sprocket member 14 do not contact the frame according to the number of rear sprockets and the frame size of the bicycle.

  When removing the sprocket main body 46, the operation handle 28c of the tool-less retaining member 28 is grasped with a finger so that the annular spring portion 34b is expanded from the connecting convex portion 44e and removed from the second groove 44g. Thereby, the sprocket body 46 can be removed without using a tool.

<Modification of First Embodiment>
In the following description, for the configuration corresponding to the configuration of the first embodiment, the code of the first embodiment is indicated by the same three-digit code with the same last two digits, and the same configuration as the configuration of the first embodiment is the same. This is indicated by a symbol.

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

  The second sliding stroke amount adjusting portion 126b is attached to one of the crank member 12 and the sprocket member 14, and a contact member 80 that contacts the other of the crank member 12 and the sprocket member 14 when the sliding mechanism 16 slides. And a shock absorbing member 82 attached to the other of the crank member 12 and the sprocket member 14. The buffer member 82 may be selectively omitted. The buffer member 82 is the same member as in the first embodiment.

  Also in the modified example, the contact member 80 is attached to the sprocket mounting portion 44 of the sprocket member 14, and the buffer member 82 is fixed to the fourth bracket 92 of the support portion 42 of the crank member 12.

  The contact member 80 has the same configuration as that of the first embodiment, and includes a contact portion 80a that comes into contact with the crank member 12 and a shaft portion 80b having a smaller diameter than the contact portion 80a. The shaft portion 80b has a male screw portion 80c and a tool engaging portion 80d. The male threaded portion 80c is screwed into a nut member 86 provided on the fifth bracket 190 formed on the inner peripheral surface of the mounting portion main body 44a of the sprocket mounting portion 44 so as to protrude radially inward. The tool engaging portion 80d is located on the opposite side of the contact portion 80a with respect to the shaft portion 80b. The fifth bracket 190 is formed on the mounting portion main body 44a at the same circumferential direction and radial position as the stopper 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 into which the nut member 86 can be detachably attached. The nut member 86 has a female screw portion 86a that is screwed into the male screw portion 80c. In addition, you may form an internal thread part in the adjustment hole 190a, without providing the nut member 86. FIG. In this case, the slit 190b is unnecessary. However, if the nut member 86 is provided, it is only necessary to replace the nut member 86 without replacing the sprocket mounting portion 44 even if the female screw portion 86a is damaged.

  In such a configuration, in the first sliding stroke amount adjusting unit 26a, the sliding stroke amount of the sprocket member 14 in the first axial direction C1 can be easily adjusted by turning the contact member 80 with a tool or the like. In the second sliding stroke amount adjusting unit 126b, the sliding stroke amount of the sprocket member 14 in the second axial direction C2 can be easily adjusted by turning the contact member 80. Thus, even if the chain and the sprocket member 14 are adjusted so as not to contact the bicycle frame, the sliding stroke amount S of the sprocket member 14 can be easily secured.

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

  The sliding mechanism 216 connects the sprocket member 214 and the crank member 212 so as to be slidable in an axial direction parallel to the rotation center axis C and to be integrally rotatable. The rattling prevention mechanism 222 is provided in the sliding portion 248 and prevents rattling between the crank member 212 and the sprocket member 214.

<Crank member>
The crank member 212 includes an arm part 40 and a support part 242. As shown in FIG. 13, the support portion 242 includes a generally rectangular support portion main body 242a and a plurality of (for example, four) first attachment portions 242b similar to 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 first attachment portion 242b is longer in the axial direction than 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. The first attachment portion 242b has a first attachment recess 242d that is inclined with respect to a plane parallel to the rotation center axis C, similarly to the first attachment portion 42b of the first embodiment. The first dust cover 224a of the dust cover 224 made of a plate material is fixed to, for example, screws at both ends in the axial direction parallel to the rotation center axis C of the first attachment portion 242b. The first dust cover 224a covers both ends of the first attachment portion 242b in the axial direction.

<Sprocket member>
13 and 14, the sprocket member 214 is a metal member such as aluminum, titanium, or iron. In FIG. 13, two of the four dust covers 224 are removed. The sprocket member 214 has a sprocket mounting portion 244 and a sprocket body 246. The sprocket mounting portion 244 is supported by the support portion 242 through the sliding mechanism 216 so as to be integrally rotatable and slidable in the axial direction parallel to the rotation center axis C.

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

  The second attachment portion 244b includes a rectangular first accommodation portion 244c that accommodates the second sliding portion 252 so as to be movable in a pressing direction P (vertical direction in FIG. 14) in which the second sliding portion 252 is pressed toward the first sliding portion 250. And a second accommodating portion 244d that accommodates a pressing member 294, which will be described later, movably in an adjustment direction A (see FIG. 14) orthogonal to the pressing direction. The 1st accommodating part 244c and the 2nd accommodating part 244d are formed over the full length of the axial direction of the 2nd attaching part 244b. The second accommodating portion 244d is longer in the adjustment direction A than the first accommodating portion 244c.

  The sprocket main body 46 has the same configuration as that of the first embodiment, and the outer periphery of the sprocket mounting portion 44 is determined by the positioning member 64 mounted in the first groove 44f and the tool-less retaining member 28 mounted in the second groove 44g. The surface is positioned in the axial direction parallel to the rotation center axis C and is prevented from coming off, 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 corners of a generally rectangular shape. Note that the retainer 256 is not shown in FIG. 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 attached integrally with the crank member 212. The second sliding portion 252 is attached to the sprocket member 14 so as to be movable in the pressing direction P. Similar to the first embodiment, the first sliding portion 250 is integrally attached to the first attachment recess 242d of the first attachment portion 242b provided in the support portion 242 of the crank member 212, for example, by adhesion. The inner surface 250a of the first sliding portion 250 engages with the first mounting recess 242d. The outer side surface 250b of the first sliding portion 250 has an inner guide 1 groove 250c having an arcuate cross section in which the rolling element 254 is guided.

  As shown in FIG. 14, the second sliding portion 252 is provided movably in the pressing direction P (vertical direction in FIG. 14) in the first housing portion 244 c of the second mounting portion 244 b provided in the sprocket mounting portion 244. . The second sliding portion 252 constitutes a sliding portion 248 and also constitutes a rattling prevention mechanism 222. The inner side surface 252b of the second sliding portion 252 has an outer guide groove 252c having a circular cross section in which the rolling element 54 is guided. The movement of the second sliding portion 252 in the direction perpendicular to the pressing direction P and the adjusting direction A (the direction orthogonal to the paper surface in FIG. 14) is restricted by the second dust cover 224b fixed to both ends of the second mounting portion 244b. The

  At least one rolling element 54 is disposed between the first sliding part 250 and the second sliding part 252. Also in the second embodiment, the rolling elements 54 are, for example, steel spheres, and two are provided at intervals along the axial direction parallel to the rotation center axis C on each sliding portion 248. The rolling element 54 may have a needle shape or a roller shape.

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

  Here, the first mounting recess 242c is formed to be inclined with respect to a plane parallel to the rotation center axis C, and the first sliding portion 250 is similarly formed to be inclined. For this reason, when the 1st sliding part 250 is adhere | attached on the 1st attachment recessed part 242c, the 1st sliding part 250 becomes difficult to scrape off an adhesive agent. Thereby, even if the first sliding portion 250 is bonded to the first mounting recess 242c, the work of wiping off the scraped adhesive can be reduced.

<Rattle prevention mechanism>
The rattling prevention mechanism 222 includes a first cam portion 252 d provided on one of the first sliding portion 250 and the second sliding portion 252, a pressing member 294, and an adjustment member 298. The pressing member 294 has a second cam portion 294a that comes into contact with the first cam portion 252d, and one of the first sliding portion 250 and the second sliding portion 252 serves as the first sliding portion 250 and the second sliding portion. 252 can be pressed toward the other side. In the present embodiment, the first cam portion 252d is provided on the second sliding portion 252 and the second cam portion 294a is provided on 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 that of the second housing portion 244d in the axial direction parallel to the rotation center axis. The pressing member 294 has a female screw portion 294c into 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 contacts 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 present embodiment, the first inclined surface 252e and the second inclined surface 294b are inclined downwardly to the left in FIG. 14 from the upstream side to the downstream side in the drive rotation direction DD of the crank assembly 210. Note that the first inclined surface 252e and the second inclined surface 294b may be inclined leftward in FIG. 14 from the upstream side to the downstream side in the drive rotation direction DD of the crank assembly 210. Further, the first cam portion 252d and the second cam portion 294a may be formed so that one cam portion has an inclined surface and the other cam portion is in line contact with the inclined surface. For example, the other cam portion may have at least one protrusion that protrudes in an arc shape and makes line contact with the inclined surface.

  The adjustment member 298 displaces the pressing member 294 so that the second cam portion 294a moves relative to the first cam portion 252d. The adjustment member 298 includes a screw shaft portion 298a that is screwed into the female screw portion 294c of the pressing member 294, a mounting shaft portion 298b having a smaller diameter than the screw shaft portion 298a, and an annular groove 298c formed in the mounting shaft portion 298b. . The adjustment member 298 is rotatably supported by the second mounting portion 244b through a first hole 244e and a second hole 244f formed with the second housing portion 244d interposed therebetween. The adjustment member 298 is prevented from coming off from the second attachment portion 244b by a retaining ring 232 (for example, E-type retaining ring) attached to the annular groove 298c. A tool engagement hole 298d is formed at the end of the adjustment member 298 on the first hole 244e side so as to be engageable with a hexagon stick wrench.

<Dust cover>
As described above, the dust cover 224 includes a plate-like first dust cover 224a that covers the first attachment portions 242b, a plate-like second dust cover 224b that covers the second attachment portions 244b, Have The first dust cover 224a is fixed to both end surfaces of the first mounting portion 242b, for example, by two screw members, respectively. The second dust cover 224b is fixed to both end surfaces of the second mounting portion 244b by, for example, three screw members.

  When the sprocket mounting portion 244 rattles against the support portion 42, the adjustment member 298 is turned in the screw return direction (counterclockwise in the case of a right screw) to move the pressing member 294 to the right in FIG. Thereby, the radial and circumferential hits of the sliding mechanism 16 can be adjusted, and rattling can be prevented.

<Modification of Second Embodiment>
In the following description, for the configuration corresponding to the configuration of the third embodiment, the code of the second embodiment is indicated by the same three-digit code with the same last two digits, and the same configuration as the configuration of the second embodiment is the same. This is indicated by a symbol.

  As shown in FIG. 15, the crank assembly 310 according to the modification of the second embodiment is different from the second embodiment in the rattling prevention mechanism 322. In the rattling prevention mechanism 322 of the modified example, the adjustment member 398 does not directly press the second sliding portion 252 but presses the second sliding portion 252 via the biasing member 334.

  The 1st accommodating part 344c is formed in a substantially rectangular shape. The second housing portion 344d has a screw hole 344e on the downstream side in the drive rotation direction DD. The pressing member 394 has a second cam portion 394a having a second inclined surface 394b having the same form as that of the second embodiment. The pressing member 394 includes a circular support recess 394c that rotatably supports the adjustment member 398. The biasing member 334 is disposed in a compressed state inside the support recess 394c. The adjustment member 398 displaces the pressing member 394 via the biasing member 334 so that the second cam portion 394a moves relative to the first cam portion 252d. The adjustment member 398 includes a screw shaft portion 398a that is screwed into the screw hole 344e, and a support shaft 398b that has a smaller diameter than the screw shaft portion 398a and is rotatably supported by the support recess 394c. The adjustment member 398 has a spring protrusion 398c for mounting the biasing member 334 and a tool engagement portion 398d for engaging a tool such as a hexagon stick wrench. The tool engaging portion 398d is formed on the end surface of the screw shaft portion 398a. The biasing member 334 includes a coil spring that is disposed in a compressed state between the adjustment member 398 and the bottom of the support recess 394c on the outer peripheral side of the spring protrusion 398c.

  In the rattling prevention mechanism 322 having such a configuration, since the second sliding portion 252 is biased by the biasing member 334 as in the first embodiment, the sliding mechanism 316 is not rattled due to wear. Even if it occurs, it can automatically reduce rattling.

<Other embodiments>
As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the summary of invention. In particular, a plurality of embodiments and modifications described in this specification can be arbitrarily combined as necessary.

  (A) Although the crankshaft 20 and the tool unnecessary retaining member 28 are provided in the first embodiment, these may not be provided, or at least one of them may be provided.

  (B) In 1st Embodiment and 2nd Embodiment, although sliding resistance was reduced using the rolling element between the support part and the sliding part, this invention is not limited to this. The support portion and the sliding portion may be directly coupled so as to be slidable and integrally rotatable. For example, the support portion and the sliding portion may be spline engaged. In this case, for example, a lubricating oil or a coating for reducing sliding resistance such as a fluorine compound coating or a hard carbon coating may be formed on at least one of the sliding portion of the support portion and the sliding portion. .

  (E) In the above two embodiments, the number of front sprocket members is one, but the present invention is not limited to this. The present invention can also be applied to a crank assembly having a plurality of front sprocket members (for example, two or three). In particular, in this case, it is possible to alleviate the degree to which the chain formed by the engagement of the minimum number of teeth or the maximum number of teeth between the front sprocket member and the rear sprocket member is arranged obliquely.

  (F) In the two embodiments described above, the thickness of each sprocket member tooth in the direction of the rotation center axis C (axial direction) is the same, but the present invention is not limited to this. For example, the total number of sprocket teeth is an even number, and the first sprocket teeth having a first axial thickness that engages with the outer link of the chain but does not engage with the inner link of the chain, and the inner link of the chain. The second sprocket teeth having a second axial thickness smaller than the first possible thickness may be alternately arranged in the circumferential direction. In such a configuration, the chain is not easily detached from the sprocket material during rotational driving.

  (G) The circumferential length of the radial tip portion of the sprocket tooth may be larger than the circumferential length of the radial intermediate portion of the sprocket member tooth with which the chain roller contacts during driving rotation. In such a configuration, the chain is not easily detached from the sprocket member during rotational driving.

10, 110, 210, 310 Bicycle crank assembly 12, 112, 212 Crank member 14, 114, 214 Sprocket member 16, 116, 216 Sliding mechanism 22, 222, 322 Shaking prevention mechanism 24, 224 Dust cover 26 Sliding stroke amount adjusting mechanism 26a First sliding stroke amount adjusting portion 48 Sliding portion 50, 250 First sliding portion 52, 252 Second sliding portion 54, 254 Rolling element 60 Contact member 62 Press adjusting member 66 Elastic member 68 Rotating member 70 Operating member 70a Male thread portion 80 Contact member 80a Contact portion 80b Shaft portion 82 Buffer member

(G) The circumferential length of the radial tip portion of the sprocket tooth may be larger than the circumferential length of the radial intermediate portion of the sprocket member tooth with which the chain roller contacts during driving rotation. In such a configuration, the chain while driving rotation may turn hard to easily disengaged from the sprocket member.

Claims (27)

A crank member;
A sprocket member having a center axis of rotation;
A sliding mechanism that slidably connects the sprocket member and the crank member in an axial direction parallel to the rotation center axis;
A backlash preventing mechanism for preventing backlash between the crank member and the sprocket member,
The bicycle crank assembly includes an elastic member.   The sliding mechanism includes a first sliding portion attached integrally with the crank member, a second sliding portion attached integrally with the sprocket member, the first sliding portion and the second sliding portion. The bicycle crank assembly according to claim 1, further comprising at least one rolling element disposed between the two parts.   The rattling prevention mechanism includes a contact member attached to one of the crank member and the sprocket member, and a pressure adjusting member attached to the other of the crank member and the sprocket member and including the elastic member, The bicycle crank assembly according to claim 2, wherein the elastic member contacts the contact member.   The elastic member has a first end and a second end, the first end of the elastic member contacts the contact member, and the pressing adjustment member is a second end of the elastic member. The bicycle crank assembly according to claim 2, comprising: a rotating member that engages with the rotating member; and an operating member that rotates the rotating member.   5. The bicycle crank assembly according to claim 4, wherein a first screw portion is formed on the other of the crank member and the sprocket member, and the operating member has a second screw portion that is screwed to the first screw portion. Solid.   The bicycle crank assembly according to any one of claims 3 to 5, wherein the contact member is a synthetic resin member extending along the axial direction.   The bicycle crank assembly according to claim 6, wherein the contact member has a sliding groove extending along the axial direction and in which the first end of the elastic member slides.   The bicycle crank assembly according to any one of claims 1 to 7, wherein the contact member is detachably fixed to one of the first crank member and the sprocket member. A crank member;
A sprocket member having a center axis of rotation;
A sliding mechanism having a plurality of sliding portions that slidably connect the sprocket member and the crank member in an axial direction parallel to the rotation center axis;
A bicycle crank assembly comprising: a plurality of dust covers attached to each of the plurality of sliding portions.   Each of the plurality of sliding portions includes a first sliding portion attached integrally with the crank member, a second sliding portion attached integrally with the sprocket member, the first sliding portion, and the The bicycle crank assembly according to claim 9, further comprising at least one rolling element disposed between the second sliding portion. A plurality of the rolling elements are provided,
Each of the plurality of rolling elements is disposed between the first sliding portion and the second sliding portion,
11. The bicycle crank assembly according to claim 10, wherein each of the plurality of sliding portions further includes a cage 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 crank member;
A sprocket member having a center axis of rotation;
A sliding mechanism that slidably connects the sprocket member and the crank member in an axial direction parallel to the rotation center axis;
A sliding stroke amount adjusting mechanism capable of adjusting a sliding stroke of the sprocket member with respect to the crank member,
The sliding stroke amount adjustment mechanism is attached to one of the crank member and the sprocket member, and has a contact member that contacts the other of the crank member and the sprocket member when the sliding mechanism slides.
The bicycle crank assembly, wherein the contact member includes a contact portion that contacts the other of the crank member and the sprocket member, and a shaft portion having a smaller diameter than the contact portion.   The sliding stroke amount adjusting mechanism includes at least one of a first sliding stroke amount adjusting unit and a second sliding stroke amount adjusting unit, and the first sliding stroke amount adjusting unit is configured to rotate the rotation center. A sliding stroke amount in a first axial direction that is separated from the crank member along the axis can be adjusted, and the second sliding stroke amount adjusting unit is configured to slide in a second axial direction opposite to the first axial direction. The bicycle crank assembly according to claim 13, wherein the stroke amount is adjustable.   The bicycle crank assembly according to claim 14, wherein the second sliding stroke amount adjustment unit is disposed on the opposite side of the rotation center axis from the first sliding stroke amount adjustment unit. The sliding stroke amount adjusting mechanism further includes a buffer member attached to the other of the crank member and the sprocket member,
The bicycle crank assembly according to any one of claims 13 to 15, wherein the buffer member is in contact with the contact portion of the contact member. A crank member;
A sprocket member having a center axis of rotation;
A sliding mechanism having a sliding portion, and slidably connecting the sprocket member and the crank member in an axial direction parallel to the rotation center axis;
A rattling prevention mechanism provided in the sliding portion for preventing rattling between the crank member and the sprocket member;
A bicycle crank assembly comprising:   The bicycle crank assembly according to claim 17, wherein the sliding mechanism has a plurality of sliding portions.   The bicycle crank assembly according to claim 18, wherein the rattling prevention mechanism is provided in each of the plurality of sliding portions. The sliding portion includes a first sliding portion attached integrally with the crank member, a second sliding portion attached integrally with the sprocket member, the first sliding portion, and the second sliding portion. A plurality of rolling elements disposed between the two parts,
The bicycle crank assembly according to any one of claims 17 to 19, wherein the rattling prevention mechanism is provided on at least one of the first sliding portion and the second sliding portion.   The bicycle crank assembly according to any one of claims 17 to 20, wherein the sliding mechanism further includes a cage that holds the plurality of rolling elements at intervals in a circumferential direction. The rattling prevention mechanism is
A first cam portion provided on one of the first sliding portion and the second sliding portion;
A second cam portion in contact with the first cam portion, wherein one of the first sliding portion and the second sliding portion is directed toward the other of the first sliding portion and the second sliding portion; A pressing member capable of pressing;
An adjustment member that displaces the pressing member such that the second cam portion moves relative to the first cam portion;
The bicycle crank assembly according to claim 20 or 21, comprising: The first cam portion has a first inclined surface,
24. The bicycle crank assembly according to claim 22, wherein the second cam portion has a second inclined surface that contacts the first inclined surface. The pressing member has a first threaded portion formed along the displacement direction of the pressing member,
24. The bicycle crank assembly according to claim 22 or 23, wherein the adjustment member has a second screw portion that is screwed into the first screw portion.   The bicycle crank assembly according to claim 24, wherein the first screw portion is a female screw portion and the second screw portion is a male screw portion. The rattling prevention mechanism is
A first cam portion provided on one of the first sliding portion and the second sliding portion;
A second cam portion in contact with the first cam portion, wherein one of the first sliding portion and the second sliding portion is directed toward the other of the first sliding portion and the second sliding portion; A pressing member capable of pressing;
An elastic member that biases the pressing member in a direction in which the second cam portion moves relative to the first cam portion;
The bicycle crank assembly according to claim 20 or 21, comprising: The first cam portion has a first inclined surface,
27. The bicycle crank assembly according to claim 26, wherein the second cam portion has a second inclined surface that contacts the first inclined surface.

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