JP2016016833A - Tensioner for electric vehicle, and electric bicycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tensioner for an electric vehicle capable of downsizing a drive unit, and increasing a tensioner capacity.SOLUTION: A drive unit 10 includes an auxiliary driving wheel 15 engaged with a drive force transmission member, and an electric motor 16 for giving rotational drive force to the auxiliary driving wheel 15. A tensioner 18 includes an arm 26 rockably provided on the drive unit 10, a tension applying wheel 27 provided on the arm 26, and energizing means 28. The tension applying wheel 27 is engaged with the drive force transmission member from the opposite side of the auxiliary driving wheel 15. The energizing means 28 energizes the arm 26 in a direction in which the tension of the drive force transmission member increases, and a rocking axis 25 of the arm 26 is the same axis as a rotation axis 37 of the auxiliary driving wheel 15.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a tensioner for an electric vehicle and an electric bicycle.

  Conventionally, an electric bicycle, which is an example of an electric vehicle, is provided on a front sprocket 102 and a rear wheel 103 that are rotated by a human driving force (stepping force) input to the pedal 101 as shown in FIGS. Some have a rear sprocket 104, a chain 105 wound between the front sprocket 102 and the rear sprocket 104, and a drive unit 106 that applies an auxiliary driving force to the chain 105.

  The drive unit 106 includes an auxiliary drive sprocket 107 that meshes with the chain 105, a motor (not shown) that rotationally drives the auxiliary drive sprocket 107, and a tensioner 109 that applies tension to the chain 105.

  The auxiliary drive sprocket 107 is provided on the output shaft 114 that is linked to the motor, and meshes with the chain 105 of the lower winding path from below to lift the chain 105. The tensioner 109 has an arm 110, a tension applying pulley 111, and a spring (not shown). The arm 110 is provided in the drive unit 106 so as to be swingable up and down via a support shaft 113. The tension applying pulley 111 is rotatably provided at the free end of the arm 110 and meshes with the chain 105 of the lower winding path from above. The spring urges the arm 110 downward.

  According to this, when the pedal 101 is depressed, the front sprocket 102 is rotated, the rotation of the front sprocket 102 is transmitted to the rear sprocket 104 via the chain 105, and the rear wheel 103 is rotated. At this time, the motor is driven according to the pedaling force applied to the pedal 101, whereby the auxiliary driving sprocket 107 is rotationally driven, and the auxiliary driving force is transmitted from the auxiliary driving sprocket 107 to the rear sprocket 104 via the chain 105. Thereby, the auxiliary driving force is added to the human driving force, and the rear wheel 103 rotates.

  At this time, since the arm 110 is urged downward by the urging force of the spring, the tension applying pulley 111 presses the chain 105 of the lower winding path downward from above, and the optimum tension is applied to the chain 105. The slack of the chain 105 can be prevented.

In addition, about the electric bicycle provided with the above tensioners, for example, the following patent document 1
It is described in.

JP 2006-341774 A

  However, in the above conventional type, the support shaft 113 of the arm 110 is provided at a position separated from the output shaft 114 of the auxiliary drive sprocket 107, so that the installation space for the tensioner 109 is increased, and the drive unit 106 is increased in size. There's a problem.

  Further, the support shaft 113 of the arm 110 is provided below the output shaft 114 of the auxiliary drive sprocket 107 and at the lower end of the drive unit 106. It may collide with obstacles such as curbs, and in such a case, there is a problem that the support shaft 113 of the arm 110 is easily damaged. As a countermeasure against such a problem, it is conceivable to increase the strength by increasing the diameter of the support shaft 113 of the arm 110. However, if the diameter of the support shaft 113 is increased, there is a problem that the drive unit 106 is further increased in size. .

  Further, when the ratio of the change amount of the circumferential length of the chain 105 to the unit swing angle of the arm 110 when the arm 110 swings up and down around the support shaft 113 is defined as the tensioner capacity, the numerical value of the tensioner capacity is obtained. It was difficult to increase the size.

  It is an object of the present invention to provide an electric vehicle tensioner and an electric bicycle capable of reducing the size of the drive unit and increasing the tensioner capacity.

In order to achieve the above object, the first aspect of the present invention provides an endless, rotatable driving force transmission member wound between one rotatable wheel and the other wheel, and a driving force transmission. A drive unit for adding auxiliary drive force to the member,
A drive unit is a rotatable auxiliary drive wheel that meshes with the drive force transmission member from either the inside or the outside of the winding path of the drive force transmission member, and an electric motor that applies rotational drive force to the auxiliary drive wheel A tensioner for applying tension to a driving force transmission member of an electric vehicle having
An arm provided in the drive unit and capable of swinging about a swing axis, a rotatable tensioning wheel provided in the arm, and an urging means;
The tensioning wheel is engaged with the driving force transmission member from the side opposite to the auxiliary driving wheel,
The biasing means biases the arm in the direction in which the tension of the driving force transmission member increases,
The swing axis of the arm is coaxial with the rotation axis of the auxiliary drive wheel.

  According to this, since the swing axis of the arm is coaxial with the rotation axis of the auxiliary drive wheel, the position of the arm swing axis differs from the position of the rotation axis of the auxiliary drive wheel. Compared to the case where the tensioner is installed, the installation space for the tensioner is reduced, and thus the drive unit can be reduced in size.

  Also, when the ratio of the amount of change in the circumferential length of the driving force transmission member to the unit swing angle of the arm when the arm swings is defined as the tensioner capacity, the swing axis of the arm rotates the auxiliary drive wheel. Because it is coaxial with the shaft center, even if the arm swings, the distance from the rotation axis of the auxiliary drive wheel to the rotation axis of the tensioning wheel is always kept constant, increasing the tensioner capacity. .

  As a result, when the driving force transmission member expands and contracts and the circumference changes, the arm swings accordingly to absorb the expansion and contraction of the driving force transmission member. Since the change amount of the swing angle of the arm with respect to the expansion / contraction amount of the member becomes small, the fluctuation of the urging force of the urging means acting on the arm is also reduced, and a relatively stable urging force with little fluctuation can be applied to the arm. it can.

In the tensioner of the electric vehicle according to the second aspect of the invention, when the angle indicating the range in which the driving force transmission member is wound around the auxiliary driving wheel is a winding angle,
The urging means decreases the urging force as the arm swings in the direction in which the winding angle increases.

  According to this, when the arm swings in the direction in which the winding angle increases, the urging force of the urging means decreases, so that an increase in the frictional resistance between the driving force transmitting member and the auxiliary driving wheel is suppressed, and the driving Reduction in power transmission efficiency and increase in noise can be suppressed. On the other hand, when the arm swings in the direction in which the winding angle decreases, the urging force of the urging means increases, so even if the number of teeth of the auxiliary driving wheel that meshes with the driving force transmitting member is small. The auxiliary driving wheel can be sufficiently engaged with the driving force transmitting member, and the occurrence of the tooth skipping phenomenon can be prevented.

In the third aspect of the invention, the tensioner of the electric vehicle is provided on the output shaft whose auxiliary drive wheel is rotated by the electric motor,
The drive unit is provided with a cylindrical fixed shaft,
The output shaft is inserted through the fixed shaft,
The arm is fitted on the fixed shaft so as to be swingable.

  According to this, by making the arm shaft a cylindrical fixed shaft, the arm shaft diameter becomes thicker and the arm shaft rigidity is improved, and the electric vehicle falls or the drive unit collides with an obstacle. Even so, breakage of the arm shaft can be prevented.

  In addition, since the output shaft is inserted through the fixed shaft, the output shaft and the fixed shaft are arranged coaxially, and the tensioner is attached compared to the case where the position of the output shaft is different from the position of the arm shaft. The space is reduced, the drive unit can be miniaturized, and the appearance is improved.

In the tensioner for an electric vehicle according to the fourth aspect of the present invention, fluctuation regulating means for regulating the movement of the arm in the swing axis direction is provided on the outer side in the radial direction of the fixed shaft.
According to this, since the arm can be prevented from changing in the direction of the swing axis, the tension applying wheel body is changed in the direction of the swing axis of the arm and the driving force transmitting member is detached from the tension applying wheel body. Can be prevented.

In the tensioner for an electric vehicle according to the fifth aspect of the present invention, the fluctuation regulating means has a long hole formed in the arm and a regulating member inserted into the long hole from the direction of the pivot axis of the arm and attached to the drive unit. And
The peripheral edge of the long hole of the arm is fitted between a part of the regulating member and the part of the drive unit that face each other in the direction of the swing axis of the arm.

  According to this, when the arm swings around the swing axis, the peripheral portion of the long hole is fitted between the part of the regulating member and the part of the drive unit so as to be integrated with the arm. It swings around the swing axis. As a result, the arm can be prevented from changing in the direction of the swing axis.

The tensioner of the electric vehicle according to the sixth aspect of the present invention is provided with a remodeling preventing member for preventing remodeling by attaching a remodeling auxiliary driving wheel having a larger diameter than a normal auxiliary driving wheel,
The modification preventing member is opposed to the outer peripheral end of the regular auxiliary driving wheel body in the radial direction in a state of being spaced a predetermined distance radially outward from the outer peripheral end of the normal auxiliary driving wheel body.

  According to this, even if you try to remodel by removing the regular auxiliary drive wheel and installing a modified auxiliary drive wheel having a larger diameter than the regular auxiliary drive wheel, the modified auxiliary drive wheel will be prevented from being modified. Since it interferes with the member, it is not possible to attach the remodeling auxiliary drive wheel body, thereby preventing unauthorized remodeling.

The seventh invention is an electric bicycle including the tensioner according to any one of the first to sixth inventions, wherein one of the wheels is a front sprocket that is rotatable together with a crankshaft.
The other ring body is a rear sprocket provided on the rear wheel.

  As described above, according to the present invention, since the pivot axis of the arm is coaxial with the rotation axis of the auxiliary drive wheel, the installation space for the tensioner can be reduced and the drive unit can be miniaturized. Further, since the tensioner capacity can be increased, even if the driving force transmission member expands and contracts and the circumference changes, a relatively stable urging force with little fluctuation can be applied to the arm.

1 is a side view of a rear half of an electric bicycle according to a first embodiment of the present invention. It is a side view of the chain and tensioner of an electric bicycle, and shows the state where the circumference of the chain contracted. It is a side view of the chain and tensioner of an electric bicycle, and shows the state where the circumference of the chain is extended. It is a cross-sectional view of the drive unit and tensioner of the electric bicycle. FIG. 2 is a partially enlarged cross-sectional view of the drive unit and the tensioner of the electric bicycle. It is a XX arrow line view in FIG. It is an enlarged side view of the tensioner of an electric bicycle. It is a graph of the noise which generate | occur | produces from the sprocket for auxiliary drives of an electric bicycle, and a tension | pulling tension pulley. It is the graph of the noise which generate | occur | produces from the sprocket for auxiliary drive of a conventional electric bicycle, and a tension | pulling provision pulley. It is a partially expanded cross-sectional view of the drive unit and tensioner of the electric bicycle according to the second embodiment of the present invention. It is a partially expanded cross-sectional view of the drive unit and tensioner of the electric bicycle in the third embodiment of the present invention. It is a side view of the rear half of the conventional electric bicycle. It is a side view of the drive unit and tensioner of the electric bicycle.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
In the first embodiment, as shown in FIG. 1, reference numeral 1 denotes an electric bicycle that is an example of an electric vehicle. The electric bicycle 1 includes a crankshaft 5 that rotates when a pedal 4 is depressed, and a crankshaft 5. Between the front sprocket 6 (an example of one wheel), a rear sprocket 8 (an example of the other wheel) provided on the rear wheel 7, and the front sprocket 6 and the rear sprocket 8. A wound endless rotatable chain 9 (an example of a driving force transmission member) wound around and a drive unit 10 that adds an auxiliary driving force to the chain 9 are provided.

  A one-way clutch 12 (see FIG. 4) is provided between the crankshaft 5 and the front sprocket 6. When the crankshaft 5 rotates in one direction C (see FIG. 2), the torque transmission path from the crankshaft 5 to the front sprocket 6 is connected by the one-way clutch 12, and the front sprocket 6 rotates together with the crankshaft 5. When the crankshaft 5 rotates in the opposite direction, the torque transmission path from the crankshaft 5 to the front sprocket 6 is interrupted by the one-way clutch 12, and the crankshaft 5 and the front sprocket 6 can be rotated individually. It becomes a state.

  As shown in FIGS. 2 to 6, the drive unit 10 is provided on the vehicle body frame 2, and is a rotatable auxiliary that meshes with the chain 9 from the lower outer side (one example of one side) of the winding path of the chain 9. A driving sprocket 15 (an example of an auxiliary driving wheel), an electric motor 16 that applies rotational driving force to the auxiliary driving sprocket 15, a case 17, a tensioner 18 that applies tension to the chain 9, and the pedal 4 are applied. And a torque sensor (not shown) for detecting a pedaling force.

  The auxiliary drive sprocket 15 is provided on the output shaft 20, and the output shaft 20 is interlocked with the rotational drive shaft 22 of the electric motor 16 via a reduction gear 21. A one-way clutch 23 is provided between the output shaft 20 and the reduction gear 21. When the motor 16 is driven, the rotational force transmission path from the reduction gear 21 to the output shaft 20 is connected by the one-way clutch 23, and the rotational driving force of the motor 16 is auxiliary driven from the reduction gear 21 through the output shaft 20. Is transmitted to the sprocket 15. In addition, when the electric motor 16 is stopped, the rotational force transmission path is interrupted by the one-way clutch 23 to prevent the load on the electric motor 16 side from acting on the chain 9.

The electric motor 16 and the reduction gear 21 are housed in the case 17.
The tensioner 18 is provided in the drive unit 10 and can swing up and down around a swing axis 25 in the left-right direction (vehicle width direction), and a rotatable tension provided at the free end of the arm 26. An application pulley 27 (an example of a tension applying ring body) and a torsion coil spring 28 (an example of an urging means) are provided.

  A hole 30 penetrating inward and outward is formed on one side surface of the case 17 of the drive unit 10, and a cylindrical fixed shaft 31 is fitted into the hole 30 and fixed to the case 17. The output shaft 20 is rotatably held in the case 17, and the distal end portion of the output shaft 20 is inserted through the fixed shaft 31 and protrudes outward. The base end portion of the arm 26 is fitted on the fixed shaft 31 so as to be swingable, and the swing axis 25 of the arm 26 is coaxial with the rotational axis 37 of the auxiliary drive sprocket 15.

  The arm 26 has a pair of left and right plate members 33 and 34 and a connecting member 35 connected between the plate members 33 and 34. The tension applying pulley 27 is provided between the plate members 33 and 34, and meshes with the chain 9 from the upper inner side (an example of the opposite side) of the winding path of the chain 9.

  The torsion coil spring 28 urges the arm 26 to swing downward (an example of a direction in which the tension of the chain 9 increases), and is externally fitted to the fixed shaft 31 so that the base end portion of the arm 26 and the case 17 is held between. One end of the torsion coil spring 28 is locked in a hole 38 (not shown) formed in the arm 26, and the other end (not shown) is locked in a hole (not shown) formed in the case 17. Yes.

  As shown in FIG. 7, when the angle indicating the range in which the chain 9 is wound around the auxiliary drive sprocket 15 is the winding angle A, the torsion coil spring 28 has the arm 26 facing downward (the direction in which the winding angle A increases). The urging force is reduced as the rocking is performed.

  As shown in FIGS. 4 to 6, on the outer side in the radial direction of the fixed shaft 31, a fluctuation regulating means 40 that regulates the fluctuation of the arm 26 in the direction B (left-right direction) of the swing axis 25 is provided. It has been. The fluctuation restricting means 40 includes a long hole 41 formed in one plate member 33 of the arm 26 and a restriction screw 42 (attached to the case 17 through the long hole 41 from the direction B of the swing axis 25. An example of a restricting member).

  The long hole 41 is an arc-shaped hole centered on the swing axis 25 and is long in the swing direction of the arm 26. The head portion 42a (an example of a part of the regulating member) of the regulating screw 42 and the boss portion 17a of the case 17 (a part of the drive unit) where the peripheral edge portion 41a of the long hole 41 opposes in the direction B of the swing axis 25 Is an example).

  The connecting member 35 of the arm 26 is modified to prevent modification by attaching a modified auxiliary driving sprocket 50 (an example of a modified auxiliary driving wheel) having a diameter larger than that of the regular auxiliary driving sprocket 15. It is an example of a prevention member. The connecting member 35 faces the outer peripheral end of the regular auxiliary driving sprocket 15 in the radial direction in a state of being separated from the outer peripheral end of the normal auxiliary driving sprocket 15 by a predetermined distance D outward in the radial direction.

Hereinafter, the operation of the above configuration will be described.
As shown in FIG. 1, when the pedal 4 is depressed, the front sprocket 6 rotates, and the rotation of the front sprocket 6 is transmitted to the rear sprocket 8 via the chain 9, and the rear wheel 7 rotates. At this time, the pedal force applied to the pedal 4 is detected by a torque sensor, and based on this detected value, as shown in FIGS. 2 and 4, the electric motor 16 is driven, and the auxiliary drive sprocket 15 is rotationally driven. Is transmitted from the auxiliary drive sprocket 15 to the rear sprocket 8 through the chain 9. Thereby, auxiliary driving force is added to human power driving force, and the rear wheel 7 rotates.

  At this time, the tension applying pulley 27 rotates as the chain 9 rotates. Further, since the arm 26 is urged downward by the urging force of the torsion coil spring 28, the tension applying pulley 27 presses the chain 9 of the lower winding path downward from above, so that the optimum tension is applied to the chain 9. The slack of the chain 9 is prevented.

  As shown in FIGS. 2 to 4 and 6, the swing axis 25 of the arm 26 is coaxial with the rotation axis 37 of the auxiliary drive sprocket 15. Compared with the case where the position of the rotation axis 37 of the drive sprocket 15 is different, the installation space for the tensioner 18 is reduced, and the drive unit 10 can be downsized.

  As shown in FIGS. 4 and 6, even if the arm 26 swings up and down, the distance E from the rotation axis 37 of the auxiliary drive sprocket 15 to the rotation axis 44 of the tension applying pulley 27 is always kept constant. As it leans, the tensioner capacity increases.

  Thus, when the chain 9 expands and contracts and the circumferential length of the chain 9 changes, the arm 26 swings up and down as shown in FIGS. 2 and 3 to absorb the expansion and contraction of the chain 9. However, since the change amount of the swing angle of the arm 26 with respect to the expansion / contraction amount of the chain 9 at this time is small, the fluctuation of the urging force of the torsion coil spring 28 acting on the arm 26 is also small, and the comparison is small. A stable urging force can always be applied to the arm 26.

For example, the electric bicycle 1 of the first embodiment is made the same size as the conventional electric bicycle shown in FIGS. 12 and 13, and the auxiliary drive sprocket 15 and the tension applying pulley 27 of the first embodiment are used. The distance E from the swing axis 25 of the arm 26 to the rotation axis 44 of the tension applying pulley 27 is the same component as the conventional auxiliary drive sprocket 107 and the tension applying pulley 111 (see FIG. 4 (see FIG. 6) is the same as the distance F (see FIG. 13) from the swing axis of the conventional arm 110 to the rotation axis of the tension applying pulley 111, in the first embodiment, When the chain 9 is expanded as shown in FIG. 3, the circumference is 440 mm. When the chain 9 is contracted as shown in FIG. 2, the circumference is 404 mm. When the chain 9 is expanded and contracted. It was swing angle of the arm 26 is 28 ° (i.e., the difference between the arm 26 angles shown in angle and 3 of arm 26 shown in FIG. 2 was 28 °). In this case, the tensioner capacity is obtained by the following formula.
(440-404) /28=1.29 mm / °
On the other hand, in the conventional apparatus, the circumferential length when the chain 105 is extended is 431 mm, the circumferential length when the chain 105 is contracted is 422 mm, and the arm 110 swings when the chain 105 is expanded and contracted. The angle was 20 °. In this case, the tensioner capacity is obtained by the following formula.
(431-422) /20=0.45 mm / °
Thereby, it was confirmed that the tensioner capacity in this 1st Embodiment increases rather than the tensioner capacity in the conventional form.

  As shown in FIG. 7, the chain 9 extends and the circumference of the chain 9 extends, and the winding angle A increases as the arm 26 swings downward, but the biasing force of the torsion coil spring 28 decreases. An increase in frictional resistance between the chain 9 and the auxiliary drive sprocket 15 is suppressed, and a decrease in driving force transmission efficiency and an increase in noise are suppressed.

  On the contrary, as shown in FIG. 2, the chain 9 contracts to shorten the circumferential length of the chain 9, and the winding angle A decreases as the arm 26 swings upward, but the biasing force of the torsion coil spring 28 is reduced. Therefore, even if the number of teeth of the auxiliary drive sprocket 15 that meshes with the chain 9 is small, the auxiliary drive sprocket 15 can sufficiently mesh with the chain 9 and the occurrence of the tooth skipping phenomenon can be prevented.

  As shown in FIGS. 4 to 6, by setting the axis of the arm 26 to the cylindrical fixed shaft 31, the axis of the arm 26, that is, the diameter of the fixed shaft 31 is increased, and the rigidity of the fixed shaft 31 is improved. Therefore, even if the electric bicycle 1 falls or the drive unit 10 collides with an obstacle such as a curbstone, the fixed shaft 31 of the arm 26 can be prevented from being broken.

  Further, since the output shaft 20 is inserted through the fixed shaft 31, the output shaft 20 and the fixed shaft 31 are arranged coaxially, and the position of the output shaft 20 and the position of the fixed shaft 31 are different from each other. Thus, the mounting space for the tensioner 18 is reduced, the drive unit 10 can be reduced in size, and the appearance is improved.

  As shown in FIGS. 4 to 6, when the arm 26 swings up and down, the peripheral edge portion 41 a of the long hole 41 is fitted between the head portion 42 a of the restriction screw 42 and the boss portion 17 a of the case 17. In this state, it swings up and down integrally with the arm 26. As a result, the arm 26 can be prevented from changing in the direction B (left-right direction) of the swing axis 25, so that the tension applying pulley 27 changes in the direction B of the swing axis 25 and the chain 9 is The separation from the tension applying pulley 27 can be prevented.

  Further, the user of the electric bicycle 1 removes the regular auxiliary drive sprocket 15 from the output shaft 20 and has a larger diameter than the regular auxiliary drive sprocket 15 as indicated by the phantom lines in FIGS. 4 and 5. Even if the modified auxiliary drive sprocket 50 is attached to the output shaft 20 for modification, the modified auxiliary drive sprocket 50 interferes with the connecting member 35 of the arm 26, so that the modified auxiliary drive sprocket 50 cannot be mounted. Thereby, unauthorized modification can be prevented.

  Further, when the electric bicycle 1 is run, the chain 9 is rotated, and the auxiliary driving sprocket 15 and the tension applying pulley 27 are rotating, noise is generated from the auxiliary driving sprocket 15 and the tension applying pulley 27, respectively. To do. A graph (a) in FIG. 8 shows a relationship between time and amplitude of noise generated from the auxiliary drive sprocket 15, and a graph (b) shows a relationship between time and amplitude of noise generated from the tension applying pulley 27. Here, when the distance E (see FIG. 4) from the rotation axis 37 of the auxiliary drive sprocket 15 to the rotation axis 44 of the tension applying pulley 27 increases or decreases, the positions of the peaks and valleys of the noise waveform in the graph (b). Is shifted in the time axis direction with respect to the positions of the peaks and valleys of the noise waveform in the graph (a). As a result, the above-mentioned distance is set to a certain distance such that the peak position of the graph (b) overlaps the valley position of the graph (a) and the valley position of the graph (b) overlaps the peak position of the graph (a). E can be set. As described above, the distance E is set to a certain distance, so that even if the arm 26 swings up and down, the rotation axis 37 of the auxiliary drive sprocket 15 and the rotation axis 44 of the tension applying pulley 27 are produced. Since the distance E between the two is always kept at the above-mentioned constant distance, as shown in the graph (c), the peaks and valleys overlap and the noise values are almost averaged.

  On the other hand, in the conventional apparatus, as shown in FIG. 13, when the arm 110 swings up and down, the distance G between the rotation axis of the auxiliary drive sprocket 107 and the rotation axis of the tension applying pulley 111. Are not constant and vary in various ways. Therefore, as shown in FIG. 9, the positions of the peaks of the waveform of the noise graph (a) generated from the auxiliary drive sprocket 107 and the waveform of the noise graph (b) generated from the tension applying pulley 111 overlap. In some cases, the positions of the valleys overlap each other. In this case, as shown in the graph (c), there is a possibility that the peak of the noise waveform may increase, and the noise may increase periodically.

(Second Embodiment)
In the second embodiment, as shown in FIG. 10, the arm 26 includes a pair of left and right plate members 33, 34, a screw member 55 (an example of a fastening member) that connects both the plate members 33, 34, And an interval maintaining member 56 for maintaining the interval between the plate members 33 and 34 at a constant interval. The distance maintaining member 56 is provided on the other plate member 34, and the screw member 55 is inserted into the distance maintaining member 56 from the other plate member 34 and screwed into the one plate member 33.

  An annular holding member 57 is provided at the base end of the other plate member 34. The distal end portion of the output shaft 20 is inserted into the holding member 57, and a bearing member 58 is provided between the outer peripheral surface of the distal end portion of the output shaft 20 and the inner peripheral surface of the holding member 57.

Hereinafter, the operation of the above configuration will be described.
When an external force is applied to the arm 26, this external force is received by the case 17 from one plate member 33 of the arm 26 via the fixed shaft 31 and from the other plate member 34 via the bearing member 58 to the output shaft 20. Can be received. As described above, since the external force acting on the arm 26 is received in a distributed manner, stress is not concentrated on the fixed shaft 31, and damage to the fixed shaft 31 can be prevented. Further, by providing the bearing member 58, the vertical swing of the arm 26 becomes smooth.

(Third embodiment)
In the third embodiment, as shown in FIG. 11, a cylindrical pin 61 is attached to the base end portion of the other plate member 34 of the arm 26. Further, a hole 62 is formed in the front end surface of the output shaft 20, and a fitting ring 63 (bush) is fitted in the hole 62. The pin 61 is inserted into the fitting ring 63. The pivot axis 25 of the arm 26, the rotation axis 37 of the auxiliary drive sprocket 15 and the axis of the pin 61 are coaxial.

Hereinafter, the operation of the above configuration will be described.
When an external force is applied to the arm 26, this external force is received by the case 17 from one plate member 33 of the arm 26 via the fixed shaft 31 and from the other plate member 34 via the pin 61 and the fitting ring 63. And received by the output shaft 20. As described above, since the external force acting on the arm 26 is received in a distributed manner, stress is not concentrated on the fixed shaft 31, and damage to the fixed shaft 31 can be prevented.

  In each of the above embodiments, as shown in FIG. 2, the auxiliary drive sprocket 15 is engaged with the chain 9 from the lower outer side, and the tension applying pulley 27 is engaged with the chain 9 from the upper inner side. The sprocket 15 may be engaged with the chain 9 from the upper inner side, and the tension applying pulley 27 may be engaged with the chain 9 from the lower outer side.

In each of the above embodiments, the chain 9 is used as an example of the driving force transmission member, but a belt may be used.
In each of the above embodiments, the torsion coil spring 28 is used as an example of the urging means, but a type of spring other than the torsion coil spring 28 may be used.

  The present invention has exemplified the electric bicycle as the electric vehicle including the tensioner. However, the present invention is not limited to the electric bicycle, and can be applied to an electric vehicle other than the electric bicycle.

1 Electric bicycle (electric vehicle)
5 Crankshaft 6 Front sprocket (one wheel)
7 Rear wheel 8 Rear sprocket (the other ring)
9 Chain (driving force transmission member)
10 Drive unit 15 Auxiliary drive sprocket (auxiliary drive wheel)
16 Electric motor 17a Boss part (a part of drive unit)
18 Tensioner 20 Output shaft 25 Oscillating axis 26 Arm 27 Tensioning pulley (Tensioning wheel)
28 Torsion coil spring (biasing means)
31 fixed shaft 35 connecting member (modification preventing member)
37 Rotational axis 40 Fluctuation restricting means 41 Long hole 41a Peripheral edge 42 of long hole Restricting screw (regulating member)
42a Head (part of the regulating member)
50 Modified auxiliary drive sprocket (remodeled auxiliary drive wheel)
A Winding angle B Oscillating axis direction D Predetermined distance

Claims (7)

An endless rotatable drive force transmission member wound between one rotatable wheel body and the other wheel body, and a drive unit for adding auxiliary drive force to the drive force transmission member,
A drive unit is a rotatable auxiliary drive wheel that meshes with the drive force transmission member from either the inside or the outside of the winding path of the drive force transmission member, and an electric motor that applies rotational drive force to the auxiliary drive wheel A tensioner for applying tension to a driving force transmission member of an electric vehicle having
An arm provided in the drive unit and capable of swinging about a swing axis, a rotatable tensioning wheel provided in the arm, and an urging means;
The tensioning wheel is engaged with the driving force transmission member from the side opposite to the auxiliary driving wheel,
The biasing means biases the arm in the direction in which the tension of the driving force transmission member increases,
A tensioner for an electric vehicle, characterized in that the swing axis of the arm is coaxial with the rotational axis of the auxiliary drive wheel. When the angle indicating the range in which the driving force transmission member is wound around the auxiliary driving wheel is a winding angle,
2. The tensioner for an electric vehicle according to claim 1, wherein the biasing force decreases as the arm swings in a direction in which the winding angle increases. The auxiliary drive wheel is provided on an output shaft that is rotated by an electric motor,
The drive unit is provided with a cylindrical fixed shaft,
The output shaft is inserted through the fixed shaft,
3. The tensioner for an electric vehicle according to claim 1, wherein the arm is fitted on the fixed shaft so as to be swingable. 4. The tensioner for an electric vehicle according to claim 3, wherein fluctuation regulating means for regulating the movement of the arm in the direction of the pivot axis is provided on the outer side in the radial direction of the fixed shaft. The fluctuation regulating means has a long hole formed in the arm, and a regulating member that is inserted into the long hole from the swing axis direction of the arm and attached to the drive unit,
5. The electric vehicle according to claim 4, wherein a peripheral edge portion of the long hole of the arm is fitted between a part of the regulating member and a part of the drive unit facing each other in the direction of the swing axis of the arm. Tensioner. The arm is provided with a remodeling prevention member for preventing remodeling by attaching a remodeling auxiliary drive wheel having a larger diameter than the regular auxiliary drive wheel,
The modification preventing member is opposed to the outer peripheral end of the normal auxiliary driving wheel body in the radial direction in a state of being spaced a predetermined distance radially outward from the outer peripheral end of the normal auxiliary driving wheel body. The tensioner of the electric vehicle according to any one of claims 1 to 5. An electric bicycle comprising the tensioner according to any one of claims 1 to 6, wherein one of the wheels is a front sprocket that is rotatable together with a crankshaft.
The other bicycle body is a rear sprocket provided on the rear wheel.

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