JPH10138986A - Assisted motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an assisted motor bicycle which can reduce the size and the weight of an auxiliary drive system and increase flexibility in the mounting structure of electric motors and produce output characteristics according to the required performance. SOLUTION: In assisted motor bicycle comprising a human power drive system and an auxiliary drive system, a plurality of electric motors 31, 32 constituting the auxiliary drive system are provided and an auxiliary power from the electric motors 31, 32 is transmitted to a resultant force shaft 37 via a common bevel gear 40. Since the plurality of electric motors 31, 32 are not arranged on the same line, the specifications of the electric motors 31, 32 can be determined freely to thereby produce output characteristics according to the required performance. Further, since the plurality of electric motors 31, 32 are not arranged in the same direction, the auxiliary drive system is not extended in one direction to thereby reduce the size and the weight of the auxiliary drive system and to increase flexibility in the mounting structure of the electric motors 31, 32.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric assisted bicycle that travels with a combined force of an occupant's pedaling force and an auxiliary power corresponding to the pedaling force.

[0002]

2. Description of the Related Art An electric assisted bicycle has been proposed which supplements the pedaling force of an occupant with an auxiliary power of an electric motor, and has already been put into practical use. A power unit that generates a corresponding auxiliary power is provided.

As an output control method of the electric motor in such an electric assist bicycle, for example, the electric motor is driven (ON) when the vehicle speed or the pedaling force exceeds a set value, and the electric motor is stopped (OFF) when the vehicle speed or the pedal force becomes equal to or less than the set value. ON)
There are known an OFF control method and a method of continuously controlling the output (auxiliary power) of an electric motor in proportion to the pedaling force.

However, the above-mentioned ON / OFF control method has a problem that a large impact is generated at the time of ON / OFF switching, and the continuous control method requires expensive transistors and thyristors for continuously controlling the motor current. In addition to the need for a simple semiconductor device, there is a problem that the structure is complicated.

[0005] Therefore, a DC electric motor is provided in which a plurality of rotors provided on a common motor shaft are rotatable in the same direction within a common stator, and a series-parallel connection by the plurality of rotors is provided. There has been proposed an electric assist bicycle in which the output of the DC electric motor is controlled by switching the combination (see Japanese Patent Application Laid-Open No. 5-310176).

Thus, according to the control method of the electric assist bicycle according to the above proposal, even if the motor output (auxiliary power) is increased or decreased according to the treading force, the electric motor is started / stopped (ON / OFF).
OFF) can be reduced with a simple configuration.

[0007]

However, in the above-mentioned electric assist bicycle, since a configuration is employed in which a plurality of electric motors are arranged on the same axis, no characteristic difference can be provided between the electric motors. In addition to being limited by the number of electric motors in terms of installation space, the length of the motor in a single direction limits the mounting structure of the electric motor, and the mounting structure requires high strength and rigidity, so the auxiliary power system is large. There is a problem that weight and weight increase.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and its object is to reduce the size and weight of the auxiliary power system and to increase the degree of freedom of the mounting structure of the electric motor. An object of the present invention is to provide an electric assist bicycle that can obtain output characteristics according to performance.

[0009]

In order to achieve the above object, an invention according to claim 1 is a human-powered drive system for transmitting a pedaling force input to a crankshaft to a resultant shaft, and a gear mechanism for transmitting auxiliary power by an electric motor. The electric assist bicycle further includes an auxiliary power system that transmits the resultant power to the resultant force shaft through a plurality of electric motors that constitute the auxiliary power system, and the auxiliary force from each electric motor is transmitted through a common gear to the resultant force shaft. Is transmitted.

According to a second aspect of the present invention, in the first aspect of the present invention, a plurality of electric motors whose output shafts are orthogonal to the crankshaft are radially arranged around the crankshaft. An auxiliary power is transmitted to the resultant shaft via a common bevel gear.

Therefore, according to the present invention, the auxiliary power from the plurality of electric motors is transmitted to the resultant shaft via the common gear, so that duplication of parts can be avoided and one point in the common gear can be avoided. It is possible to reduce the size of parts by lowering the transmission force per contact.

Further, since a plurality of electric motors are not arranged on the same axis, the specifications of each electric motor can be freely determined without being affected by the performance and shape of the other electric motors. Output characteristics can be obtained.

Furthermore, since the plurality of electric motors are not arranged in a single direction, the auxiliary power system does not become longer in a single direction, so that the size and weight of the auxiliary power system can be reduced and each electric motor can be reduced. The degree of freedom of the mounting structure is increased.

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

<Embodiment> FIG. 1 is a side view of an electric assisted bicycle according to Embodiment 1 of the present invention, FIG. 2 is a side view of a power unit of the electric bicycle, and FIG. 3 is a cross section taken along line AA of FIG. FIG.

First, a schematic configuration of the electric assist bicycle 1 will be described with reference to FIG.

In FIG. 1, reference numeral 2 denotes a body frame which forms a substantially parallelogram in a side view, and a handle stem 4 is rotatably inserted into a head pipe 3 located forward of the vehicle body of the body frame 2. ing. A handle 5 is attached to an end of the handle stem 4, and a front fork 6 is attached to a lower end of the handle stem 4. A front wheel 7 is attached to a front axle 8 at a lower end of the front fork 6. It is rotatably supported by.

A main pipe 9 extends substantially horizontally from the head pipe 2 toward the rear of the vehicle body.
The down tube 10 extends obliquely downward toward the rear of the vehicle body, and a seat tube 11 is erected from the lower end of the down tube 10 obliquely upward toward the rear of the vehicle body. A saddle 13 is supported at the upper end of the seat tube 11 via a seat post 12 so as to be adjustable in height.

By the way, a power unit 30 is suspended substantially below the center of the vehicle body and at a portion where the down tube 10 and the seat tube 11 are connected. The power unit 30 is provided with a human-powered driving system based on the pedaling force of an occupant and an auxiliary power system including two electric motors 31 and 32, and a crankshaft 14 is rotatably supported on the power unit 30. 15 cranks on both sides
Is attached, and a pedal 16 is attached to the end of each crank 15.
Is supported.

A controller 17 is provided on the down tube 10 near the power unit 30. A battery box 18 is detachably mounted on the upper front side of the seat tube 11 above the power unit 30. I have. The battery box 18 contains a plurality of shrink-packed D cells (single-cell batteries).
(Not shown) is stored.

On the other hand, a pair of right and left chain stays 19 extend from the power unit 30 toward the rear of the vehicle body. The rear end of the chain stay 19 is inclined from the rear end of the main pipe 9 toward the rear of the vehicle body. It is connected to the lower ends of a pair of left and right seat stays 20 extending downward. A rear wheel 21 is rotatably supported by a rear axle 22 at a connecting portion between the chain stay 19 and the seat stay 20, and a small-diameter wheel sprocket 23 is connected to the rear axle 22 via a one-way clutch (not shown). Supported rotatably.

Here, the configuration of the power unit 30 will be described in detail with reference to FIGS.

As shown in FIG. 3, the case 33 of the power unit 30 has the crankshaft 14 rotatably supported by bearings 34 and 35. The crankshaft 14 has a planetary gear mechanism 36 and a hollow resultant force. A shaft 37 is provided. The resultant shaft 37 is rotatably supported by a case 33. The crank shaft 14 is rotatably supported by a bearing 38 in the resultant shaft 37. The planetary gear mechanism 36 is mounted on the outer periphery of the inner end of the resultant shaft 37. A bevel gear 40 and a drum-shaped ring gear 39, which constitute a part of the shaft 33, are connected to each other. And FIG.
As shown in FIG. 1, an endless chain 26 is wound between the drive sprocket 24 and the wheel sprocket 23 and the tension roller 25.

The planetary gear mechanism 36 includes a sun gear 41 fixed on a crankshaft 141, a ring-shaped carrier 43 supported on the crankshaft 14 via a one-way clutch 42, and a carrier 43. Shaft 44
It comprises a plurality (three in this embodiment) of planetary gears 45 rotatably supported by the ring gear 39 and each of the planetary gears 45 is located between the sun gear 41 and the ring gear 39 and is located on both sides. Are engaged. In the present embodiment, the ring gear 39 and the bevel gear 40
Are connected and integrated by a plurality of rivets 46.

In the present embodiment, as shown in FIG. 2, two electric motors 31 and 32 are radially arranged in the power unit 30 in a V-shape when viewed from the side with the crankshaft 14 as a center. And the electric motors 31 and 3
2 output shafts (motor shafts) 31a and 32a
4 extends inward in the radial direction in a direction perpendicular to 4. The output shafts 31a of the electric motors 31, 32,
Small-diameter bevel gears 47 and 48 are connected to the end of 32a, and both bevel gears 47 and 48 mesh with the bevel gear 40. In the present embodiment,
The one (front) electric motor 31 is disposed to be inclined substantially horizontally forward, and the other (rear) electric motor 32 is disposed to be substantially vertically erected.

Next, the operation of the battery-assisted bicycle 1 will be described.

When the occupant depresses the left and right pedals 16 to rotate the crankshaft 141, the rotation of the crankshaft 14 is increased in speed by the planetary gear mechanism 36 and transmitted to the resultant shaft 37. In this embodiment, Since the carrier 43 of the planetary gear mechanism 36 is fixed (strictly speaking, the spring of the reaction force receiving portion not shown rotates by an angle corresponding to the amount of compression deformation by the reaction force), the pedaling force of the occupant is The light is output from the ring gear 39 via the planetary gear 41 and the planetary gear 45 and transmitted to the resultant shaft 37.

In the process in which the pedaling force is transmitted to the resultant shaft 37 via the planetary gear mechanism 36 as described above, the planetary gear 45
Receives a reaction force due to meshing with the ring gear 39, and this reaction force is transmitted to a reaction force receiving portion (not shown) and is received by a spring of the reaction force receiving portion. The carrier 43 rotates about the crankshaft 14 by an angle corresponding to the amount of compression deformation of the spring.

Since the reaction force acting on the planetary gear 45 is proportional to the magnitude of the stepping force of the occupant, and the amount of compressive deformation of the spring is proportional to the magnitude of the reaction force, the rotation angle of the carrier 43 is determined by the stepping force. Is proportional to the size of Therefore, the pedaling force can be detected by detecting the rotation angle of the carrier 43,
The rotation angle of the carrier 43 is detected by detection means (not shown), and the detection signal is transmitted to the controller 17 (FIG. 1).
Output). Then, the controller 17
Calculates the pedaling force based on the detection signal from the detecting means, and controls the two electric motors 31 and 32 so as to generate auxiliary power according to the magnitude of the determined pedaling force. still,
The controller 17 and the electric motors 31 and 32 operate by receiving power supply from a battery (not shown) housed in the battery box 18 (see FIG. 1).

The rotation of the output shafts 31a and 32a of the electric motors 31 and 32 is input to the common bevel gear 40 via the bevel gears 47 and 48 and transmitted to the resultant shaft 37. The auxiliary power generated at 32 is transmitted to the resultant shaft 37 via the above path.

As a result, the resultant shaft 376 is driven to rotate by the occupant's pedaling force and auxiliary power, and the rotation is transmitted to the rear wheel 21 via the drive sprocket 24, the chain 26, the wheel sprocket 23, and the rear axle 22.
The rear wheel 21 is rotationally driven by both the occupant's treading power and the auxiliary power, and the electric assist bicycle 1 is caused to travel. As a result, the physical burden required for the occupant to travel is reduced.

In the above, according to the present embodiment, the auxiliary power from each of the electric motors 31, 32 is transmitted to the resultant shaft 37 via the common bevel gear 40, so that duplication of parts can be avoided. In addition, it is possible to reduce the transmission force per position in the common bevel gear 40 and to reduce the size of parts.

Since the two electric motors 31 and 32 are arranged radially around the crankshaft 14 and are not arranged at least on the same axis, each electric motor 31 (3
The specification 2) can be freely determined without being affected by the performance and shape of the other electric motors 32 (31), and output characteristics according to required performance can be obtained. For example, a high torque / low rotation type motor is used for one electric motor 31 and a low torque / high rotation type motor is used for the other electric motor 32, and the output ratio between the two electric motors 31 and 32 is optimally controlled. Thus, a high torque can be obtained at the time of starting or climbing a hill, and a high speed can be obtained at the time of general traveling on a flat road.

Further, according to the present embodiment, since the electric motors 31, 32 are not arranged in a single direction, the auxiliary power system does not become longer in the single direction, and the size of the auxiliary power system can be reduced. While reducing the weight, each electric motor 31,
The degree of freedom of the mounting structure of 32 is expanded.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a side view of the battery-assisted bicycle according to Embodiment 2 of the present invention. In FIG. 4, the same elements as those shown in FIG. 1 are denoted by the same reference numerals. Is omitted.

Also in the electric assist bicycle 1 according to the present embodiment, the power unit 30 has two electric motors 3
Although the first and second motors 32 are radially arranged around the crankshaft 14 in a V-shape when viewed from the side, in this embodiment, the rear electric motor 32 is arranged along the seat tube 11. , And its periphery is covered by a cover 50. The other configuration is the same as that of the electric assisted bicycle 1 shown in the first embodiment.

Therefore, also in the present embodiment, the same effect as in the first embodiment can be obtained.

In the first and second embodiments, the two electric motors are arranged radially around the crankshaft. However, three or more electric motors may be arranged in the same manner, or two or more electric motors may be arranged. The electric motors described above may be arranged such that their output shafts are parallel to the crankshaft, and each output shaft may be meshed with a common spur gear.

[0039]

As is apparent from the above description, according to the present invention, a human-powered driving system for transmitting the pedaling force input to the crankshaft to the resultant shaft, and the auxiliary power by the electric motor via the gear mechanism, the resultant force. In an electric assist bicycle having an auxiliary power system for transmitting power to a shaft, a plurality of electric motors constituting the auxiliary power system are provided, and auxiliary power from each electric motor is transmitted to the resultant shaft via a common gear. With this configuration, the size and weight of the auxiliary power system can be reduced, the degree of freedom of the mounting structure of the electric motor can be increased, and output characteristics corresponding to required performance can be obtained.

[Brief description of the drawings]

FIG. 1 is a side view of a battery-assisted bicycle according to Embodiment 1 of the present invention.

FIG. 2 is a side view of the power unit of the electric bicycle according to Embodiment 1 of the present invention.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a side view of an electrically assisted bicycle according to Embodiment 2 of the present invention.

[Explanation of symbols]

 Reference Signs List 1 electric assisted bicycle 14 crankshaft 30 power unit 31, 32 electric motor 31a, 32a output shaft 37 resultant shaft 40 bevel gear (common gear)

Claims (2)

[Claims] 1. An electric assist bicycle comprising a human-powered drive system for transmitting a pedaling force input to a crankshaft to a resultant shaft and an auxiliary power system for transmitting auxiliary power from an electric motor to the resultant shaft via a gear mechanism. The electric assist bicycle according to claim 1, wherein a plurality of electric motors constituting the auxiliary power system are provided, and auxiliary power from each electric motor is transmitted to the resultant shaft via a common gear. 2. A plurality of electric motors whose output shafts are orthogonal to the crankshaft are arranged radially around the crankshaft, and auxiliary power from each electric motor is transmitted to the resultant shaft via a common bevel gear. The battery-assisted bicycle according to claim 1, wherein