JP2007276603A - Bicycle tensioner device, and bicycle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bicycle tensioner device which is capable of reducing manufacturing cost while high accuracy is not required in a manufacturing step, and minimizing the adjustment of a tension pulley mounting position while any play is hardly generated even if a chain is expanded. <P>SOLUTION: The bicycle tensioner device automatically adjusts the tension of a chain 3 by applying an urging force from an urging means from a tension pulley 51 to the chain 3. The outer circumferential surface 51a of the tension pulley 51 is formed in a shape in slidable contact with an inner portion having an endless shape of the chain 3 while being not protruded between rollers of the chain 3. Thus, the manufacturing cost can be reduced, and the tension pulley mounting position for the engagement of the chain with teeth of the tension pulley need not be adjusted. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a bicycle tensioner device having a tension pulley that automatically adjusts the tension of a chain.

  Some bicycles have an exterior transmission at the freewheel portion of the rear wheel. The exterior transmission includes a plurality of rear wheel sprockets (so-called rear wheel free wheels or small gears) having different diameters attached to the rear wheels, and is arranged so as to face these rear wheel sprockets from below, and is used for changing gear stages. A guide pulley that is moved left and right by a wire to switch the gear position, and a tension pulley that is biased in the direction of tensioning (increasing tension) by a biasing means such as a helical spring to absorb slack in the chain during shifting Etc. In some bicycles, an exterior transmission is provided in the crank portion.

  Similarly, as a bicycle equipped with a tension pulley, by adding the auxiliary driving force of the motor drive unit generated by the electric motor to the human driving force generated by the stepping force of the person from the pedal, the bicycle can run easily on hills etc. In the electric bicycle constructed as shown in FIG. 10, as shown in FIG. 10, the tension pulley 1 increases the winding angle with which the chain 3 of the driving sprocket 2 that outputs the auxiliary driving force is engaged, and absorbs the slack of the chain 3, and the chain 3 There is one that keeps the tension state of the sheet moderate (see, for example, Patent Document 1).

  As an example of the attachment structure of the tension pulley 1 in the case shown in FIG. 10, as shown in FIGS. 9 and 11, the outer shell portion of a motor drive unit 10 incorporating an electric motor as a source of auxiliary drive force is provided. A support arm 13 is swingably attached to the unit case 11 via the support shaft 12, and the tension pulley 1 is rotatably attached to the tip of the support arm 13 via the pulley shaft 14. Further, a biasing spring 15 made of a helical spring as a biasing means is externally mounted on the outer peripheral side of the support shaft 12, and one end of the biasing spring 15 is engaged with an engagement hole 11 a provided in the unit case 11. Further, the other end of the urging spring 15 is engaged with an engagement hole 13 a provided in the support arm 13, and the urging spring 15 urges the tension pulley 1 to rotate in the direction “a”. 3 is stretched (given tension). In FIG. 10, 16 is a crankshaft, 17 is a chain sprocket (so-called large gear or gear plate) that rotates integrally with the crankshaft, and 11b in FIG. 9 is a boss formed on the unit case 11. The mounting screw portion of the support arm 13 is screwed and the biasing spring 15 is externally provided with a gap.

  Here, as shown in FIG. 12, chains (specifically, roller chains) 3 to be maintained at an appropriate tension by the tension pulley 1 are arranged in pairs on the left and right sides, and the letter “8” is seen from the side. A plate-shaped outer plate 3a and inner plate 3b, a roller 3c disposed between the outer plates 3a or between the inner plates 3b, a bush 3d disposed inside the roller 3c between the outer plates 3a, an outer It consists of a hole formed in the plate 3a and the inner plate 3b and a pin 3e inserted through the central hole of the bush 3d. The outer plate 3a and the inner plate 3b with the roller 3c interposed are connected to the pin 3e. It is set as the structure connected sequentially. Although not shown, there is also a chain 3 having a structure in which the bush 3d is omitted by replacing the portion corresponding to the bush 3d with a cylindrical portion provided on the inner plate 3b.

The tension pulley 1 that applies tension to the chain 3 has a shape in which a plurality of tooth portions 1a are formed around it as shown in FIG. 13, and the tooth portions 1a are formed as shown by phantom lines in FIG. In this state, tension is applied to the chain 3 while the tension pulley 1 is rotated while being inserted between the rollers 3c of the chain 3.
JP 2001-63677 A

  However, the tension pulley 1 having the above structure is generally manufactured by resin molding or the like. However, since the tooth portion 1a is inserted between the rollers 3c of the chain 3, the tension pulley 1 between the rollers 3c of the chain 3 is inserted. Therefore, it has to be manufactured with high accuracy in a shape that fits well, and this has led to an increase in manufacturing cost.

  Further, since the chain sprocket 17 for transmitting the manpower driving force and the driving sprocket 2 for transmitting the auxiliary driving force have a structure with teeth, the chain sprocket 17 and the chain 3 meshed with the driving sprocket 2 are In some cases, it is necessary to adjust the attachment position of the tension pulley 1 so that the tooth portion 1a of the tension pulley 1 is inserted between the rollers 3c of the chain 3 well. Sometimes it took.

  Furthermore, the chain 3 may extend due to aging due to long-term use, but in this case, the chain 3 may not be engaged with the tooth portion 1a of the tension pulley 1 and there is a risk of rattling.

  The present invention solves the above-mentioned problems, and does not require high accuracy in the manufacturing process, thereby reducing the manufacturing cost and minimizing the adjustment of the tension pulley mounting position. Moreover, it is an object of the present invention to provide a bicycle tensioner device and a bicycle that are less likely to be rattled even when the chain is extended.

  In order to solve the above-described problems, the present invention provides a tension pulley that contacts a chain that transmits a driving force from a chain sprocket that rotates together with a crankshaft to a freewheel of a rear wheel, and a pulley shaft that is provided at the center of the tension pulley. A support arm for rotatably supporting the tension pulley via a tensioning force, and a biasing means for biasing the support arm in a direction to increase the tension of the chain, and the biasing force from the biasing means is a tension pulley. A tensioner device for a bicycle that automatically adjusts the tension of the chain by applying it to the chain from the outer peripheral surface of the tension pulley to the endless inner portion of the chain without protruding between the rollers of the chain. It is characterized in that it is formed in a slidable shape.

  With this configuration, the outer peripheral surface of the tension pulley can be slidably contacted with the endless inner portion of the chain to apply tension to the chain, but there are locations corresponding to the teeth of the conventional tension pulley. The shape of the tension pulley can be reduced, and the manufacturing cost of the tension pulley does not need to be high, and the manufacturing cost can be reduced. There is no need to adjust the installation position of the tension pulley for meshing with the chain, and even if the chain extends over time due to long-term use, it is caused by the conventional meshing of the teeth between the chain and the tension pulley. There will be no spoil.

  As described above, according to the present invention, the outer peripheral surface portion of the tension pulley is formed so as to be in sliding contact with the endless inner portion of the chain without entering between the rollers of the chain. The manufacturing cost can be reduced without the need for high accuracy, and the tension pulley mounting position for meshing between the chain and the tension pulley teeth can be adjusted as in the past. As a result, the work efficiency of the mounting work is improved, and even if the chain extends due to aging due to long-term use, rattling with the tooth portion does not occur.

  According to the present invention, a tension pulley that contacts a chain that transmits a driving force from a chain sprocket that rotates together with a crankshaft to a rear wheel sprocket, and the tension pulley can be rotated via a pulley shaft provided at the center of the tension pulley. And a biasing means for biasing the support arm in a direction to increase the tension of the chain, and applying a biasing force from the biasing means to the chain from the tension pulley. A tensioner device for a bicycle that automatically adjusts tension, wherein an outer peripheral surface portion of the tension pulley is formed in a shape that is in sliding contact with an endless inner portion of the chain without entering between the rollers of the chain. And

  With this structure, the outer peripheral surface portion of the tension pulley can be slidably contacted with the endless inner portion of the chain to provide tension to the chain, but a portion corresponding to the tooth portion of the conventional tension pulley is provided. This eliminates the need for a simple shape, thereby eliminating the need for high accuracy in the tension pulley manufacturing process and reducing the manufacturing cost. In addition, since the tension pulley does not have a tooth portion that enters between the rollers of the chain, it is not necessary to adjust the attachment position of the tension pulley for meshing the chain and the tooth portion of the tension pulley, Further, even if the chain extends due to aging due to long-term use, rattling due to the conventional meshing of the tooth portion between the chain and the tension pulley does not occur.

  Here, as a specific shape of the tension pulley, hook-shaped portions that restrict the movement of the chain in the width direction of the tension pulley are formed at both ends in the width direction of the tension pulley, or a substantially central portion in the width direction of the tension pulley. In addition, a convex portion that slides on the chain roller and restricts the movement of the chain in the tension pulley width direction is formed, or the movement of the chain in the width direction of the tension pulley is restricted at both ends of the tension pulley in the width direction. A hook-shaped portion is formed, and a convex portion that is slidably contacted with the roller of the chain is formed at a substantially central portion in the width direction of the tension pulley.

  With this configuration, the chain can be slid well to be applied with tension while being regulated by the hook-shaped portion or the convex portion so that the chain does not move away from the tension pulley in the width direction.

  In addition, the present invention is a bicycle including the tensioner device. As an example of the bicycle, the bicycle is an electric bicycle including a motor drive unit that generates an auxiliary driving force to be added to the human power driving force. The pulley is also used as a guide pulley that guides the chain so as to increase the winding angle with which the chain is engaged with the drive sprocket that outputs the auxiliary driving force from the motor drive unit. The tension pulley of the tensioner device can not only provide good tension to the chain, but can also serve as a guide pulley that guides the chain so as to increase the winding angle of the chain.

  Further, as another example of the bicycle provided with the tensioner device of the present invention, the bicycle has a plurality of shift sprockets attached coaxially, and a guide pulley that is moved in the axial direction and switches these sprockets. The tension pulley is disposed adjacent to the guide pulley and absorbs the slack of the chain at the time of shifting. According to this configuration, the slack of the chain at the time of shifting is well absorbed by the tension pulley. can do.

  Hereinafter, a tensioner device according to an embodiment of the present invention and a bicycle provided with the tensioner device will be described with reference to the drawings. In the drawings according to the following embodiments, the bicycle is an electric bicycle. In addition, the same code | symbol is attached | subjected to the thing of the same function as the component of the electric bicycle provided with the conventional tensioner apparatus shown in FIGS.

  As shown in FIGS. 1 to 4 and the like, the electric bicycle including the tensioner device 50 according to the embodiment of the present invention includes a head pipe 21, a front fork 22, a main frame 23, a standing pipe 24, a hanger lug 25 (FIG. 3). The frame body 30 including the chain stay 26, the back fork 27, the front wheel 31 rotatably assembled to the lower end portion of the front fork 22, and the head pipe 21 from above to be integrated with the front fork 22. A handle stem 32 and a handle 33 assembled so as to rotate to each other, a saddle 29 attached to an upper end portion of a seat post 28 inserted into the standing pipe 24, and a pedal 34 to which a manpower driving force (stepping force) is applied are cranked. While supporting the crankshaft 16 attached via the arm 35 rotatably, The motor drive unit 10 provided with the electric motor 37 and the speed reduction mechanism 38 that generate the auxiliary drive force, the drive sprocket 2 that outputs the auxiliary drive force, and the like, and the rear wheel 41 that is rotatably attached to the rear end of the chain stay 26. And a battery unit 42 disposed between the standing pipe 24 and the rear wheel 41, and a crankshaft 16 connected via a rotating shaft 44 having a one-way clutch mechanism 43 so that the crankshaft 16 is stopped. The chain sprocket 17 rotatably arranged, the rear wheel sprocket 46 assembled to the central shaft portion of the rear wheel 41, the manpower driving force from the chain sprocket 17 and the auxiliary driving force from the driving sprocket 2 are used as the rear wheel sprocket. 46, the chain sprocket 17, the upper part of the chain 3, and the motor drive unit 0 has a such as a cover 48 which covers from the side of the. Note that the electric bicycle shown in this embodiment does not have an exterior transmission.

  The motor drive unit 10 detects a pedaling force from the pedal 34 by a torque sensor 36 provided in the motor driving unit 10, and outputs an auxiliary driving force from the driving sprocket 2 in accordance with the pedaling force. The force and the auxiliary driving force are combined and transmitted to the rear wheel 41 side via the chain 3, so that the vehicle can easily travel on a slope. Further, the speed reduction mechanism 38 is also provided with a one-way clutch mechanism 39 so that when the electric motor 37 is not driven, a load from the electric motor 37 side on the chain 3 does not act. Moreover, in this embodiment, as shown in FIG. 4, the unit case 11 that forms the outer shell portion of the motor drive unit 10 includes a motor case portion 11c that covers the electric motor 37 portion, and a bicycle traveling direction other than the motor portion. The left case portion 11d that covers the portion that becomes the left side and the right case portion 11e that covers the right side portion are used, which are divided into three parts and are connected and fixed to each other with bolts or the like. It is not a thing. Further, the motor drive unit 10 is fixed to the hanger lug 25 in the frame body 10 and its vicinity via the support brackets 40 and 45.

  Also in this electric bicycle, the motor drive unit 10 is arranged at a position where the crankshaft 16 is disposed and a position near the rear thereof, which is a low position in the center of the electric bicycle in the front-rear direction. In addition, as shown in FIG. 5, the drive sprocket 2 is arranged at a rear position near the chain sprocket 17, and during traveling, the chain 3 for transmitting the driving force meshes with the chain sprocket 17 and moves from the upper side to the lower side. After that, the lower part of the chain 3 is lifted by the drive sprocket 2. Further, a tensioner device 50 that guides the chain 3 and applies an appropriate tension is arranged further rearward of the drive sprocket 2, and the chain 3 lifted by the drive sprocket 2 by a tension pulley 51 provided in the tensioner device 50. Is pushed down to guide the drive sprocket 2 so that the winding angle with which the chain 3 is engaged increases.

  As shown in FIGS. 5, 6, and 9, the tensioner device 50 provided in the electric bicycle includes a tension pulley 51 that is in contact with the chain 3 and a pulley shaft 14 that is provided at the axis of the tension pulley 51. A support arm 13 that rotatably supports the tension pulley 51, and is interposed between the support arm 13 and the unit case 11, and swings the support arm 13 in a direction that increases the tension of the chain 3 via the support arm 13. It is comprised from the urging | biasing spring 15 as an urging means to urge | bias.

  Also in this embodiment, as shown in FIGS. 6 and 9, a biasing spring 15 made up of a helical spring as a biasing means is provided on the outer peripheral side of the support shaft 12, and one end of the biasing spring 15 is provided. Is engaged with an engagement hole 11 a provided in the unit case 11, and the other end of the urging spring 15 is engaged with an engagement hole 13 a provided in the support arm 13. The chain 51 is urged so as to rotate 51 in the direction a to give tension to the chain 3.

  Here, in particular, in the present invention, the outer peripheral surface portion 51a of the tension pulley 51 in the tensioner device 50 is replaced with a tooth portion 1a like the conventional tension pulley 1 as shown in FIGS. 6, 7A, and 7B. (Refer to FIG. 13 and the like) and is formed in a shape that is in sliding contact with an endless inner portion (inner portion of the loop) 3f of the chain 3 in a state where it does not enter between the rollers 3c of the chain 3. In this embodiment, hook-shaped parts 51b that restrict movement of the chain 3 in the width direction of the tension pulley (that is, the left-right direction) are integrally formed at both ends of the tension pulley 51 in the width direction. The portion in the middle has a simple planar shape when viewed in cross section.

  In this configuration, in the tension pulley 51 according to the embodiment of the present invention, the portion between the flange portions 51b on the outer peripheral surface portion 51a of the tension pulley 51 is the endless inner portion of the chain 3 (more specifically, the outer side of the chain 3). The urging force of the urging spring 15 can be favorably applied from the tension pulley 51 to the chain 3 in a state of sliding contact with the inner bulging portion of the plate 3a and the inner plate 3b. The tension can be maintained.

  The outer peripheral surface portion 51a of the tension pulley 51 does not have the tooth portion 1a that enters between the rollers 3c of the chain 3 as in the prior art, and the endless inner portion of the chain 3 without entering between the rollers 3c of the chain 3 Since it is formed in a shape that comes into sliding contact with 3f, it is not necessary to provide a portion corresponding to the tooth portion 1a of the conventional tension pulley 1, and a simple shape can be obtained. Without this, the tension pulley 51 can be manufactured satisfactorily, and as a result, the manufacturing cost can be reduced.

  Further, in the conventional tension pulley 1, the tension pulley 1 may have to be mounted so that the teeth 1 a of the tension pulley 1 are inserted between the rollers 3 c of the chain 3. Since the tension pulley 51 according to the embodiment of the invention does not have the tooth portion 1a that protrudes between the rollers 3c of the chain 3, the tension pulley for meshing the chain 3 and the tooth portion of the tension pulley as in the prior art. Therefore, the attachment position of the tensioner device 50 including the tension pulley 51 can be efficiently attached.

  Furthermore, when the chain 3 is extended due to aging due to long-term use, if the conventional tension pulley 1 is used, the chain 3 may not mesh with the teeth 1a of the tension pulley 1 and may cause rattling. In the tension pulley 51 according to the embodiment of the present invention, even when the chain 3 is extended, the outer peripheral surface portion 51a of the tension pulley 51 is slidably in contact with the endless inner portion 3f of the chain 3, and the conventional tooth portion meshes. No wobbling due to

  Further, according to the above configuration, the hook 3 51 b that restricts the movement of the chain 3 in the tension pulley width direction is formed at both ends of the tension pulley 51 in the width direction. Even if it moves in the direction and tries to leave, the outer surface of the outer plate 3a of the chain 3 and the end surface of the pin 3e are prevented from moving against the flange 51b of the tension pulley 51. Separation can be prevented well.

Moreover, although the case where the hook-shaped part 51b was formed in the width direction both ends was described as the shape of the outer peripheral surface part 51a of the tension pulley 51 in the said embodiment, it does not restrict to this.
That is, as shown in FIGS. 7C and 7D, a protrusion that is slidably contacted with the roller 3c of the chain 3 and that restricts the movement of the chain 3 in the width direction of the tension pulley is provided at a substantially central portion in the width direction of the tension pulley 51. The shape part 51c may be formed.

  According to this configuration, the convex portion 51c portion of the outer peripheral surface portion 51a of the tension pulley 51 is an endless inner portion of the chain 3 (more specifically, the inner bulging portion of the outer plate 3a and the inner plate 3b of the chain 3). ), The biasing force of the biasing spring 15 can be favorably applied to the chain 3 from the tension pulley 51, and the chain 3 can be maintained in a state in which a good tension is loaded.

  Further, even if the chain 3 moves from the tension pulley 51 in the width direction and is about to be detached, the inner surface of the inner plate 3 b of the chain 3 is prevented from moving in contact with the convex portion 51 c of the tension pulley 51. Therefore, the detachment of the chain 3 can be prevented satisfactorily.

  Further, as shown in FIGS. 7 (e) and 7 (f), hook-shaped portions 51 b that restrict the movement of the chain 3 in the width direction of the tension pulley are formed at both ends in the width direction of the tension pulley 51. A convex portion 51 c that is in sliding contact with the roller 3 c of the chain 3 may be formed at a substantially central portion of the width direction 51.

  According to this configuration, the convex portion 51c portion of the outer peripheral surface portion 51a of the tension pulley 51 is an endless inner portion of the chain 3 (more specifically, the inner bulging portion of the outer plate 3a and the inner plate 3b of the chain 3). ), The biasing force of the biasing spring 15 can be favorably applied to the chain 3 from the tension pulley 51, and the chain 3 can be maintained in a state in which a good tension is loaded.

  Further, even if the chain 3 moves from the tension pulley 51 in the width direction and is about to be detached, the inner surface of the inner plate 3 b of the chain 3 is prevented from moving in contact with the convex portion 51 c of the tension pulley 51. Therefore, it is possible to prevent the chain 3 from being detached, and even if the inner plate 3b of the chain 3 gets over the convex portion 51c of the tension pulley 51, the outer surface of the outer plate 3a of the chain 3 can be prevented. In addition, since the end surface of the pin 3e is prevented from moving in contact with the flange 51b of the tension pulley 51, the chain 3 can be more reliably prevented from being detached.

  Next, FIG. 8 shows an electric bicycle provided with a tensioner device according to another embodiment of the present invention. In this electric bicycle, an exterior transmission 60 is provided at the freewheel portion of the rear wheel 41 of the electric bicycle. As shown in FIG. 8, in this type of electric bicycle, a plurality of rear wheel sprockets 61 having different diameters are coaxially attached to the free wheel portion of the rear wheel 41, and an exterior transmission 60 is attached in the vicinity thereof. It has been. The exterior transmission 60 includes a guide pulley 62 disposed in a posture that is movable to the left and right below the rear wheel sprocket 61, a tension pulley 51 that absorbs slackness of the chain 3 at the time of shifting, and an operation lever for shifting. A moving mechanism 64 driven by a wire connected to the rear wheel sprocket, and the guide pulley 62 and the tension pulley 51 are moved in the left-right direction by the moving mechanism 64 so that the chain 3 meshes with the rear wheel sprocket. 61 is switched to change the speed. The tension pulley 51 of the exterior transmission 60 has a function of adjusting the tension of the chain 3.

  Here, in this embodiment, the tension pulley 51 of the exterior transmission 60 has the same shape as that shown in FIGS. 7A and 7B (the outer peripheral surface portion 51a of the tension pulley 51 has no tooth portion. Thus, the outer peripheral surface portion 51a of the tension pulley 51 has a shape that is in sliding contact with the endless inner portion 3f of the chain 3). Also by this, similarly to the tension pulley 51 described above, the biasing force of the biasing spring 15 can be favorably applied from the tension pulley 51 to the chain 3, and the chain 3 is in a state in which a good tension is loaded. In addition, the tension pulley 51 can be manufactured at low cost without requiring high accuracy in the manufacturing process. Further, there is no need to adjust the tension pulley mounting position for meshing between the chain 3 and the teeth of the tension pulley as in the prior art, and the tensioner device 50 including the tension pulley 51 can be mounted efficiently. Even when the chain 3 is extended, the outer peripheral surface portion 51a of the tension pulley 51 is in good sliding contact with the endless inner portion 3f of the chain 3, and rattling may occur due to the meshing of the conventional tooth portion. Absent. Instead of this, as the tension pulley 51 of the exterior transmission 60, the one shown in FIGS. 7C and 7D and the one shown in FIGS. 7E and 7F may be used.

  In this embodiment, a guide device 50 ′ having a function of guiding the chain 3 is arranged further rearward of the drive sprocket 2, and the guide pulley 51 ′ provided in the guide device 50 ′ drives the drive device. The chain 3 lifted by the sprocket 2 is pushed down to guide the winding angle at which the chain 3 meshes with the drive sprocket 2 to increase. This guide device 50 'is energized from the tensioner device shown in FIG. The spring 15 is omitted, and the support arm 13 attached to the unit case 11 at a predetermined position and posture is used (not shown). And guide pulley 51 'provided in this guide apparatus 50' also has what is shown in Drawing 7 (a) and (b) (or what is shown in Drawing 7 (c) and (d), Drawing 7 (e), (F) may be used, so that the guide pulley 51 'can be manufactured at a low cost, and the conventional chain 3 and tension can be used. There is no need to adjust the position of the tension pulley for meshing with the teeth of the pulley, and even when the chain 3 is extended, there is no rattling caused by the meshing of the conventional teeth. There are advantages.

  Polyacetal (POM) and polyamide (PA) are suitable as materials for the tension pulley 51 and the guide pulley 51 'in each of the above embodiments. However, the material is not limited to this, and is inexpensive, easy to slide, and durable. Something is desirable.

  In the embodiment shown in FIG. 8, the case where the exterior transmission 60 is provided in the free wheel portion of the rear wheel 41 is described, but the present invention is not limited to this, and the exterior transmission is provided in the crank portion. Of course, it is also applicable.

  In the above embodiment, the case where the tensioner device 50 is provided in the electric bicycle has been described. However, the present invention is not limited to this. For example, a tensioner device having a similar structure can be used for a general bicycle. is there.

  The tensioner device of the present invention can be used as a tensioner device for various types of bicycles including electric bicycles, but it can also be used as a guide device for simply guiding a chain by omitting an urging means.

The whole side view of the electric bicycle provided with the tensioner device concerning an embodiment of the invention Side view showing the rear from the center of the electric bicycle The perspective view which shows the attachment state of the motor drive unit of the electric bicycle Schematic plan sectional view of the motor drive unit of the electric bicycle Side view of the unit case of the electric bicycle and its vicinity Perspective view of the tensioner device of the electric bicycle (A) And (b) is the partial notch front view and side view of the tension pulley of the tensioner apparatus, (c) And (d) is the partial notch front view and side view of the tension pulley of another modification, (e) And (f) is a partially cutaway front view and side view of a tension pulley according to another modification. The side view which shows the rear part from the center part of the electric bicycle provided with the tensioner apparatus which concerns on embodiment of this invention Disassembled perspective view of the tensioner device (the tension pulley is omitted, and shows the common part between the conventional one and this embodiment) Side view of a conventional electric bicycle unit case and its vicinity Perspective view of the conventional electric bicycle tensioner device (A) and (b) are an enlarged side view and a partially cutaway plan view of the chain. (A) And (b) is a partial notch front view and side view of a tension pulley of a conventional tensioner device

Explanation of symbols

2 Drive sprocket 3 Chain 3c Roller 3f Inner part 10 Motor drive unit 11 Unit case 13 Support arm 14 Pulley shaft 15 Energizing spring (urging means)
16 Crankshaft 17 Chain sprocket 37 Electric motor 46 Rear wheel sprocket 50 Tensioner device 51 Tension pulley 51a Outer peripheral surface portion 51b Hook-shaped portion 51c Convex-shaped portion

Claims (7)

  A tension pulley that contacts the chain that transmits the driving force from the chain sprocket that rotates together with the crankshaft to the rear wheel sprocket, and a support that rotatably supports the tension pulley via a pulley shaft provided at the center of the tension pulley. And an urging means for urging the support arm in a direction to increase the tension of the chain, and automatically applying the urging force from the urging means to the chain from a tension pulley. A tensioner device for a bicycle that is adjusted to a shape, wherein an outer peripheral surface portion of the tension pulley is formed so as to be in sliding contact with an endless inner portion of the chain without entering between the rollers of the chain.   The bicycle tensioner device according to claim 1, wherein hook-shaped portions for restricting movement of the chain in the width direction of the tension pulley are formed at both ends in the width direction of the tension pulley.   2. The bicycle tensioner device according to claim 1, wherein a convex portion is formed at a substantially central portion in the width direction of the tension pulley so as to be in sliding contact with the roller of the chain and restrict movement of the chain in the width direction of the tension pulley.   At both ends in the width direction of the tension pulley, hook-shaped portions that restrict the movement of the chain in the width direction of the tension pulley are formed, and at the substantially central portion of the tension pulley in the width direction, a convex portion that is in sliding contact with the roller of the chain is formed. The bicycle tensioner device according to claim 1.   A bicycle comprising the bicycle tensioner device according to any one of claims 1 to 4.   The bicycle is an electric bicycle provided with a motor drive unit that generates an auxiliary drive force to be added to the human drive force. The tension pulley of the tensioner device is connected to the drive sprocket that outputs the auxiliary drive force from the motor drive unit. 6. The bicycle according to claim 5, which is also used as a guide pulley for guiding the chain so as to increase the meshing winding angle.   A bicycle includes a plurality of gear shifting sprockets attached coaxially and a guide pulley that is moved in the axial direction to switch between the sprockets, and a tension pulley is disposed adjacent to the guide pulley. The bicycle according to claim 5, which absorbs slack in the chain during gear shifting.

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