JP4446541B2 - Electric bicycle - Google Patents

Description

BACKGROUND OF THE INVENTION
The present invention relates to an electric bicycle, and more specifically, by arranging each member in a chain mechanism including a front gear, a rear gear, a drive gear to which a driving force from a motor is transmitted, and the like in a predetermined arrangement, The present invention relates to an electric bicycle that extends the life of a chain and eliminates the need for providing an axis of a drive gear more than necessary.
[0001]
[Prior art]
2. Description of the Related Art In recent years, electric bicycles that are equipped with a propulsion assist mechanism including a battery, a motor, and the like on a bicycle and assist driving by using the driving force of the motor at a low speed are commercially available (see Japanese Patent Application Laid-Open No. 7-156856, etc.). )
[0002]
The mechanism of such an electric bicycle will be briefly described with reference to FIG. 7. Based on the speed / torque detected by the speed / torque detector 91 provided at the shaft center of the pedal 81, a CPU, a memory, etc. A control unit (not shown) incorporating a motor determines the driving force of the motor 92, and the driving force of the motor 92 is transmitted to a driving gear (not shown in FIG. 7) engaged with the chain 94. The driving force is a force that assists the propulsion of the bicycle. In this way, the bicycle is assisted.
[0003]
The relationship between the chain and the drive gear will be described in detail. As shown in FIG. 8, the upper chain 94a is connected so that the drive gear 93 that transmits the driving force of the motor 92 can reliably transmit the driving force to the chain 94. Bite from above. The reason for this structure is that when the driver is stroking the pedal 81, a clockwise rotational force as indicated by an arrow B in FIG. As shown by arrow A, the upper chain 94a and the drive gear 93 are reliably engaged with each other by being slightly urged upward as indicated by the arrow A. Because. In particular, it is known that the tension force in the tension state is very large when the pedal 81 is started from a stationary state (that is, a state where the speed is zero).
[0004]
[Problems to be solved by the invention]
As described above, since the upper chain 94a is in a tension state and is slightly pressed and biased upward as indicated by the arrow A, the chain 94 is firmly engaged with the drive gear 93, but in other words, firmly The more the teeth are engaged, the greater the friction with respect to the chain 94 by the drive gear 93 and the more the chain 94 is worn. In fact, experience and experiments have shown that the wear rate of the chain 94 of an electric bicycle is faster than the wear rate of a chain on a normal bicycle.
[0005]
Conversely, when viewed from the drive gear 93, the upward pressing force by the upper chain 94a is applied to the shaft center 931 of the drive gear. The shaft center 931 may be directly the shaft center of a motor (not shown), or may be provided with a gear or the like to transmit the driving force of the motor. In any case, there is a problem in that the axial center 931 has to be strengthened more than necessary because a pressing force is applied to the axial center 931 in the upward direction of the chain 94a.
[0006]
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an electric bicycle that extends the life of the chain and eliminates the need for providing the shaft center of the drive gear more than necessary. .
[0008]
[Means for Solving the Problems]
The electric bicycle according to the present invention that solves the above problems is engaged with the front gear 30 connected to the pedal 61, the rear gear 36 connected to the central shaft of the rear wheel, and the front gear 30 and the rear gear 36. The chain mechanism includes a chain 32 that transmits the pedaling force input from the pedal 61 to the rear wheel, and a drive gear 33 that transmits the driving force from the motor to the chain 32 while transmitting the driving force to the chain 32. X, and the drive gear 33 meshes with the lower chain 32b so that a part of the lower chain 32b of the chain 32 is driven downward, and the chain and the rear gear of the portion with which the drive gear 33 is engaged A tensioner 34 that presses the chain 32 between the chain that engages 36 and the chain 32 is engaged with the chain 32.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an electric bicycle 1 according to a reference example will be described in detail with reference to the drawings.
As shown in FIG. 1, the electric bicycle 1 according to the reference example includes a front wheel 71, a rear wheel 72, a saddle 9, and the like, as in a normal electric bicycle. The description of the members used in is omitted.
[0012]
( Reference example )
In the reference example , as shown in FIG. 2, the chain mechanism X includes a front gear 30 connected to the pedal 61, a rear gear (not shown) connected to the center shaft 73 of the rear wheel, And a chain 32 that meshes with the front gear 30 and the rear gear. Further, the driving gear 33 to which the driving force from the motor is transmitted is engaged with the chain 32 so as to lift a part of the lower chain 32 b and transmits the driving force of the motor to the chain 32. In addition, a tensioner 34 that presses the chain 32 substantially downward is provided between the part of the chain 32c thus lifted and the part of the chain 32 that meshes with the rear gear. The tensioner 34 is engaged with the lower chain 32b.
[0013]
The movement of the lower chain 32b from the front gear 30 to the rear gear will be described. When the pedal 61 is stepped on, the chain 32b engaged with the front gear 30 by the stepping force moves to the left in FIG. The engagement with the front gear 30 is released, and the upper gear 30 is lifted upward. Next, the engagement with the drive gear 33 is released, and it is pushed down substantially downward by the tensioner 34. Thus, in the reference example , the lower chain 32b meanders in a “h” shape.
[0014]
When the chain 32b pushed down substantially downward by the tensioner 34 further proceeds in the left direction in FIG. 2, the engagement with the tensioner 34 is released, and thereafter, as in a normal bicycle, the chain 32b proceeds toward the rear gear, It turns back by the rear gear and proceeds to the right in FIG. 2 to become the upper chain 32a. Thus, the pedaling force generated by stepping on the pedal 61 is transmitted to the rear gear and becomes a propulsive force. Of course, when the motor is driven to assist the traveling of the electric bicycle 1 according to the reference example , such as when the pedaling force is insufficient, the driving force from the motor is transmitted to the chain 32 via the drive gear 33. Thus, the motor assists the traveling of the electric bicycle 1 according to the reference example .
[0015]
As described above, in the reference example , since the drive gear 33 is engaged with the lower chain 32b instead of the upper chain 32a, the tension force applied to the upper chain 32a when stroking the pedal 61 is It does not participate in the drive gear 33. Therefore, since the friction of the chain 32 can be reduced as compared with the conventional electric bicycle, the life of the chain 32 can be extended. In addition, since the lower chain 32 b meanders in a “h” shape as described above, the driving force from the motor can be steadily transmitted to the chain 32 via the driving gear 33. Unlike the conventional electric bicycle, the tension force is not applied to the drive gear shaft 331, so that it is not necessary to reinforce the drive gear shaft 331 more than necessary.
[0016]
As described above, for example, when the upper chain 32a is in tension with the pin, such as when the pedal 61 is depressed, the lower chain 32b is slightly loosened. In order to alleviate the looseness of the lower chain 32b, the drive gear 33 is preferably provided with a one-way clutch (not shown). Due to this one-way clutch, the drive gear 33 rotates freely in the counterclockwise direction (that is, the direction in which the chain 32 is forwardly fed) in FIG. 2, but rotates in the clockwise direction (that is, in the direction in which the chain 32 is reversed). Disappear. That is, the slack of the lower chain 32b can pass through the drive gear 33, but once it has passed through the drive gear 33, it cannot return to the front gear 30 beyond the drive gear 33 by the one-way clutch. In this way, in the reference example , the looseness of the lower chain 32b can be dispersed throughout the lower chain 32b. Thereby, it is possible to effectively prevent the chain 32 from being inadvertently detached from the gears 30 or the like.
[0017]
Next, the tensioner 34 that presses the lower chain 32b substantially downward will be described in detail. The tensioner 34 has a gear shape, and the gear meshes with the lower chain 32b. The tensioner 34 moves the chain 32 to a predetermined pressure in a direction as indicated by an arrow C in FIG. 2, that is, a diagonally downward front side, so that the portion of the chain 32 c lifted by the drive gear 33 has a “H” shape. It is pressed with. In the present specification, the “substantially (substantially) downward direction” includes not only the vertical direction but also such an obliquely forward downward direction and an obliquely backward downward direction. Of these, it is preferable that the tensioner 34 is pressed diagonally forward and downward so that the lower chain 32b and the drive gear 33 can be reliably engaged with each other. Although not shown, the tensioner 34 presses the chain 32 by an elastic member such as a spring attached to a member fixed to the electric bicycle 1 according to the reference example such as a motor.
[0018]
Moreover, it is preferable that the axial center 341 of the tensioner is located below the axial center 331 of the drive gear. This is because the length of the chain 32c in the lifted portion can be increased, and the driving force of the driving gear 33 can be transmitted to the chain 32 more reliably. In other words, if the drive gear 33 is a circle and the length of the chain 32 that meshes with the circumference of the drive gear 33 is a circumference, the drive gear 33 is more surely as the circumference angle (winding angle) of the circumference can be increased. Therefore, in the reference example , it is preferable that the tensioner shaft center 341 is positioned below the drive gear shaft center 331 in the reference example .
[0019]
In the reference example , it is preferable to provide a cover 5 as shown in FIG. The cover 5 covers the front gear 30, the drive gear 33, and the tensioner 34, and covers at least a part of the upper chain 32a and the lower chain 32b from the front gear 30 through the drive gear 33 to the tensioner 34. The cover 5 is made of a single piece of metal or plastic. By providing such a cover 5, it is possible to prevent rust and dirt on the front gear 30 and the like, and in particular, it is possible to prevent clothing such as trousers and skirts from being caught in the chain mechanism X. In particular, when the portion covering the chain 32 is formed in a U-shaped cross section or a U-shaped cross section, it is possible to more effectively prevent rust, dirt, and entrainment of clothing.
[0020]
Further, since the cover 5 is made of a single metal or plastic, the cover 5 can be easily removed. For this reason, the maintenance with respect to the chain mechanism X can be performed easily. Further, such a cover 5 can enhance the aesthetic appearance of the electric bicycle 1 according to the reference example .
[0021]
In the illustrated electric bicycle, the shaft center of the drive gear 33 and the shaft center of the motor that supplies driving force to the drive gear 33 are connected by a single shaft center. As described above, by positioning the motor below the upper chain 32a, it is possible to further reduce the center of gravity of the electric bicycle according to the reference example . It goes without saying that further lowering the center of gravity contributes to more stable driving for the driver.
[0022]
(In the form state of implementation)
Figure 4 shows an implementation in the form of a chain mechanism in the electric bicycle 1 according to the present invention. Chain mechanism X for definitive the form status of the present embodiment ', the pedal front wheel 30 coupled to a (not shown in FIG. 4)' and, after being coupled to the central axis of the rear wheel (not shown in FIG. 4) A side gear 36 ′ and a chain 32 ′ engaged with the front gear 30 ′ and the rear gear 36 ′ are provided. Further, the driving gear 33 ′ to which the driving force from the motor is transmitted is engaged so as to drive a part of the lower chain 32 b downward , and transmits the driving force of the motor to the chain 32. In addition, a tensioner 34 ′ that presses the chain 32 substantially upward is provided between the chain 32 d that has been driven down in this way and the chain 32 that meshes with the rear gear 36 ′. . The tensioner 34 'is engaged with the lower chain 32b.
[0023]
The movement of the lower chain 32b from the front gear 30 'to the rear gear 36' will be described. When the pedal is stepped on, the chain 32b engaged with the front gear 30 'by the stepping force is moved to the left in FIG. As a result, the engagement with the front gear 30 'is released and the engagement with the drive gear 33' is made. Next, the meshing with the drive gear 33 'is released and it is pushed down substantially upward by the tensioner 34'. Thus, in the present invention, the lower chain 32 'meanders in a crank shape.
[0024]
The chain 32b 'pushed down substantially upward by the tensioner 34' is then released from the engagement with the tensioner 34, and then proceeds toward the rear gear 36 'in the same manner as in a normal bicycle. It turns back by 36 'and proceeds to the right in FIG. 4 to become the upper chain 32a'. In this way, the pedaling force generated by stepping on the pedal is transmitted to the rear gear 36 'and becomes a propulsive force. Note that the assistance for driving the bicycle by the motor is the same as in the reference example .
[0025]
As described above, Oite the form status of the present embodiment, 'rather than the lower side of the chain 32 b' upper chain 32a drive gear 33 'so is occlusion, like the reference example, the chain 32' Can extend the lifetime of Further, since the lower chain 32 meanders in a crank shape as described above, the driving force from the motor can be steadily transmitted to the chain 32 ′ via the driving gear 33 ′. Unlike the conventional electric bicycle, the tension force is not applied to the drive gear shaft 331 ′, so that it is not necessary to reinforce the drive gear shaft 331 ′ more than necessary.
[0026]
Further, the area surrounded by the chain 32 'can be reduced as compared with the reference example . Therefore, the whole chain mechanism X can be reduced in size, the electric bicycle 1 according to the present invention can be made compact, and the aesthetic appearance can be enhanced.
[0027]
Next, the tensioner 34 ′ that presses the lower chain 32b ′ substantially upward will be described in detail. The tensioner 34 'has a gear shape, and this gear meshes with the lower chain 32b'. The tensioner 34 ′ has the chain 32 ′ in the direction indicated by the arrow D in FIG. 4, that is, the diagonally forward upper direction so that the lower chain 32 b ′ engaged with the drive gear 33 ′ has a crank shape as a whole. Pressing with a predetermined pressure. In this specification, the “substantially (almost) upward direction” includes not only the vertical direction but also such an oblique front upper direction and oblique rear upward direction. Of these, it is preferable that the tensioner 34 ′ is pressed obliquely forward upward so that the lower chain 32 b ′ and the drive gear 33 ′ can be reliably engaged with each other. The elastic member of the tensioner 34, the one-way clutch in the drive gear 33 ′, and the cover 5 are the same as those in the reference example .
[0028]
Further, the tensioner shaft center 341 ′ is preferably located above the drive gear shaft center 331 ′. Thereby, similarly to the reference example , the winding angle can be increased, and the driving force of the driving gear 33 ′ can be reliably transmitted to the chain 32 ′.
[0029]
(About frame hanger)
In this reference example , as shown in FIGS. 5 and 6, a cylindrical frame hanger 4 is provided at the lower end of the standing pipe 27 provided at the lower portion of the saddle 9. In the frame hanger 4, a speed / torque detector 41 that detects speed / torque, which is information for determining the driving force of the motor, is inserted in the electric bicycle 1. A shaft center 42 of the speed / torque detector 41 protrudes from the frame hanger 4, and a front gear and a pedal (both not shown in FIGS. 5 and 6) are provided on the protruding portion.
[0030]
The frame hanger 4 is composed of a cylindrical frame hanger body 43, and the frame hanger body 43 has an axial direction from one end of the cylinder as shown in FIG. 6 in a state where the electric bicycle 1 according to the reference example is laid down. A split 44 is provided in parallel with the. A pair of fastening portions 45 are provided on the outer peripheral surface of the frame hanger body 43 so as to sandwich the split 44. As described above, the frame hanger 4 includes the cylindrical frame hanger main body 43 provided with the split 44 and the pair of fastening portions 45 provided on the outer peripheral surface of the frame hanger main body with the split 44 interposed therebetween.
[0031]
The pair of fastening portions 45 are provided with overlapping holes (not shown). Bolts 46 pass through the holes, and nuts (not shown) receive the bolts 46. When the bolt 46 is tightened, the width of the split 44 is narrowed, so that the speed / torque detector 41 inserted in the frame hanger 4 is securely fixed in the frame hanger 4. On the other hand, when the bolt 46 is loosened, the width of the split 44 is restored, so that the speed / torque detector 41 can be slid in the front side and back direction (up and down direction in FIG. 6) of the electric bicycle 1, The speed / torque detector 41 can be inserted into and removed from the frame hanger 4.
[0032]
In the conventional electric bicycle, once the speed / torque detector 41 is inserted into the frame hanger 4, it is fixed at that position, and the speed / torque detector 41 is slightly moved in the forward / backward direction. It was difficult to adjust. For this reason, the front gear connected to the shaft center 42 of the speed / torque detector 41 and the rear gear are displaced in plan view (when the electric bicycle is viewed from above), and the front gear and the rear gear In some cases, the chain that meshes with the torsion would meander in plan view.
[0033]
However, in the reference example , as described above, by loosening the bolt 46, the speed / torque detector 41 can be slid toward the front / back of the electric bicycle 1, so that the speed can be appropriately set. The torque detector 41 can be slid and finely adjusted so that the chain meshed with the front gear and the rear gear is a straight line in plan view. Further, the speed / torque detector 41 can be easily inserted into and removed from the frame hanger 4 as compared with a conventional electric bicycle.
[0034]
In the above description, the bolt 46 and the nut are used. However, instead of this, if a female screw is engraved in a hole provided in the pair of fastening portions 45 and the bolt 46 is rotated in the tightening direction, The fastening portions 45 may be close to each other, and conversely, if the bolts 46 are rotated in a loosening direction, the pair of fastening portions 45 may be separated. The “speed / torque detector” may be a detector that detects either speed or torque, or may be a detector that detects both speed and torque.
[0035]
【The invention's effect】
According to the present invention, the life of the chain 32 used in the chain mechanism X can be extended. In the present invention, since the tension generated in the upper chain 32a is not applied to the drive gear shaft 331, it is not necessary to reinforce the drive gear shaft 331 more than necessary.
[Brief description of the drawings]
[1] a chain mechanism X in a state where the cover 5 in a side view [3] Figure 2 shows a chain mechanism X in the whole side view Figure 2 Reference Example of the electric bicycle 1 according to the reference example is provided motorized bicycle according to the enlarged view Figure 6 reference example of frame hanger 4 in schematic side view Figure 5 reference example showing a chain mechanism X 'which definitive the form status of implementation of the enlarged cross-sectional view FIG. 4 the invention shown Fig. 7 is an enlarged view of a frame hanger 4 in a state in which 1 is laid. Fig. 7 is an overall view of a conventional electric bicycle. Fig. 8 is a schematic side view showing a chain mechanism in a conventional electric bicycle.
DESCRIPTION OF SYMBOLS 1 ... Electric bicycle 27 ... Center pipe 30 ... Front gear 32 ... Chain 32a ... Upper chain 32b ... Lower chain 32c ... Chain 32d of the part lifted by the drive gear 33 ... Chain 32d of the part pushed down
33 ... Drive gear 331 ... Drive gear shaft 34 ... Tensioner 341 ... Tensioner shaft 36 ... Rear gear 5 ... Cover 61 ... Pedal 4 ... Frame hanger 41 ... Speed / torque detector 42 ... Speed / torque detector Axle 43 ... Frame hanger body 44 ... Split 45 ... Pair of fastening portions 46 ... Bolt 71 ... Front wheel 72 ... Rear wheel 73 ... Rear wheel center shaft 81 ... Pedal 9 ... Saddle 91 ... Speed / torque detector 92 ... Motor 93 ... Drive gear 931 ... Drive gear shaft 94 ... Chain 94a ... Upper chain 95 ... Front gear X ... Chain mechanism

Claims (1)

Meshed with the front gear (30) connected to the pedal (61), the rear gear (36) connected to the center axis of the rear wheel, the front gear (30) and the rear gear (36) The chain (32) for transmitting the pedaling force input from the pedal (61) to the rear wheel, and the driving force from the motor are transmitted to the chain (32), and the driving force is applied to the chain (32). A chain mechanism (X) composed of a transmission gear (33) for transmission, wherein the drive gear (33) drives a part of the lower chain (32b) of the chain (32) downward. The chain (32) between the part of the chain engaged with the lower chain (32b) and the part of the chain engaged with the rear gear (36) and the part of the chain engaged with the drive gear (33) is substantially upward. Tensioner that presses against (34) is meshed with the chain (32), motorized bicycles.

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