JP2002046685A - Tire of power assisted bicycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power assisted bicycle with minimum change of exchanging a rear wheel of an existent bicycle. SOLUTION: In a tire of the power assisted bicycle, an outer rotor type DC brushless motor is used for a motor driven by a torque proportional to a man power driving force transmitted by a chain, the motor is connected with a man power transmission mechanism without a gear, by detecting a man power driving force through torsion torque generated in the transmission mechanism a small sized and lightened motor is realized, and the tire is formed in a unit with a battery and a control device for the operation of the above function.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrically assisted bicycle for driving a vehicle by inputting a human driving force and an electric driving force to a driving portion provided in a hub.

[0002]

2. Description of the Related Art A conventional electric power assisted bicycle has a drive motor, a reduction gear, and a torque detector housed in a hub of a rear wheel as described in Japanese Patent Application Laid-Open No. 10-324288.

This electrically assisted bicycle has two driving forces, one of which is a driving force from a pedal, which is transmitted to the rotating side of a casing via a chain to rotate wheels, and the other is a driving force. One is a driving force that detects the torque applied to the pedal in the hub, rotates the motor with a torque of the same magnitude as the torque, and rotates the wheels via the speed reduction mechanism.

[0004] In the case of the above-mentioned electric assist type bicycle, since a reduction gear is provided, it is not possible to combine the bicycle into a compact mechanism, and it is necessary to change the basic structure from a normal bicycle.
The structure of the assisted bicycle had to be special. For this reason, the cost is high.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks, and has as its object to provide an existing bicycle as an assist type bicycle with a minimum change.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a human-powered driving force is received by a sprocket (1) connected to a one-way clutch (2) provided to be connected to an axle (9), and is driven along the axle (9). At the shaft end of the one-way clutch (2) on the side opposite to the sprocket (1), a disc-shaped joint 1 (3) provided with a through-hole of the axle (9) is provided. From the outer peripheral end of the joint 1 (3), Again, it is folded back in the axial direction on the sprocket (1) side by a flexible joint (4), and the end face of the flexible joint (4) on the sprocket side and the rotating casing (6) of the outer rotor type DC brushless motor are connected by a joint 2 (5). Combine
It features gearless simplification of the configuration and higher efficiency.

A motor stator frame (11) is connected to a support (12) fixed to an axle (9), and the rotor is connected to the support (1).
By supporting with the bearing (13) provided in 2), the gap between the stator core (17) of the outer rotor structure that rotates the outside of the stator and the rotor magnet (14) can be kept constant even in a vehicle with impact. Features a structure that can be maintained.

The magnet 2 (8) provided on the joint 2 (5) is arranged in a similar relationship to the motor rotor magnet (14), and the magnetic flux detector 2 (16) detects the current polarity of the stator coil (18). It is characterized in that the position of the rotor necessary for switching is detected.

Further, the battery is integrated with the inside of the drive unit hub by connecting the battery case 1 (21) and the battery case 2 (22) to the column (12).

The battery can be separated from the hub by providing a cover that can be connected to the battery by a cable instead of the battery storage case (21).

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described based on a tire of an electrically assisted bicycle.

First, the relationship between the overall configuration and the present invention will be described with reference to FIG.

Reference numeral 32 denotes a rear wheel tire of the present invention. The rear wheel tire (32) connects the axle (9) to the frame 1 (25).
And supported by the frame 2 (26).

When the pedal (35) is depressed by human power, the rear wheel tire (32) passes through a chain (36) to the sprocket (1) of the drive unit (29) in FIG. Is transmitted. As a result, the bicycle moves forward. In the present invention, the manual driving force is detected, and the motor in the drive unit is driven to assist the manual driving.

FIG. 1 shows a specific configuration of the drive unit (29) described above.

In FIG. 1, a driving force from a pedal (35) is transmitted to a sprocket (1) via a chain (36), and further transmitted to a one-way clutch (2) connected to the sprocket (1). . The one-way clutch (2) is joined to the sprocket (1) via a ratchet (not shown). That is, the input from the chain (34) is applied only in one direction by the ratchet, and when a force is applied in the reverse rotation direction, the driving force is cut off.

The joint 1 (3) has a disc shape with a through hole for the axle (9), the lower end of the axle side is connected to the one-way clutch (2), and the upper end is bent at the sprocket side. (4). The flexible joint (4) has a cylindrical shape having an inner diameter larger than the outer shape of the one-way clutch (2). The opposite surface of the flexible joint (4) is connected to a disc-shaped joint 2 (5).
The other end of (5) is screwed to the rotor-side casing (6) so that a spoke crimp hole (23) provided in the rotor-side casing (6) and a rim to which the rear wheel tire (32) is attached. (33) multiple spokes (34)
The tire can be rotated and run with the torque transmitted by depressing the pedal.

On the other hand, the rotor core (1
No. 0) is coupled to the rotor side casing (6) so as not to be displaced from the axial center in the bicycle running direction, and a permanent magnet (14) is attached to the surface of the rotor core (10). . A stator core (17) is provided at a fixed gap distance from the permanent magnet (14), and a stator coil (18) is wound around the stator core (17). The stator core (17) is connected to a cylindrical stator frame (11).
1) is supported and fixed by a column (12) having a pseudo-cross-shaped cross section connected to an axle (9).

The horizontal axis of the column (12) whose cross section is a pseudo-cross shape is cylindrical, and the stator core (17) and the rotor core (1)
In order to keep the gap distance between the permanent magnets (14) attached to the surface of (0) constant, a bearing (13) supporting the rotor casing (6) is attached. Thereby, the gap of the air gap can be kept constant. The vertical axis is a thick plate, the lower end of which is connected to and fixed to the axle, and the upper end of which is connected to the stator core (11) to support the motor stator.

Next, a method for detecting the position of the rotor and a method for detecting the manual driving force for switching the current polarity of the stator coil (18) of the motor will be described with reference to FIG.

As is well known, the principle of rotation of a DC brushless motor utilizes an attractive force and a repulsive force generated between a rotor magnet (14) and a stator coil (18), so that the stator coil is changed depending on the rotor position. The rotation is continued by switching the direction of the flowing current. In the present invention, the position is indirectly detected by the magnet 2 (8) provided in the joint 2 (5) in FIG. As shown in FIG. 2, the position of the magnet 2 (8) can be detected by making the arrangement of the magnet 2 (8) proportional to the rotation radius of the rotor magnet (14) and providing them in a similar relationship. here,
The magnetic flux detectors 2 (16) need to detect each of the phases a, b, and c in accordance with the position of the stator coil (18), and three are provided at intervals of 120 electrical degrees. Then, the N and S poles of the magnet are detected as shown in FIG. 3, and a drive signal for an inverter (46) described later is obtained.

As described above, since the position is always detected, the assisted bicycle which needs to drive the assist motor only when the manual driving force is detected can be driven in synchronization with the speed, and the control with good response can be achieved. I can do it.

Next, a method for detecting a manual driving force will be described. The magnet (7) provided in the joint 1 (3) is replaced with the rotor magnet (14) in FIG. 2 and the magnet (8) provided in the joint 2 (5).
The N and S poles are arranged so as to be similar to the radius of gyration in the same relationship as the above. The flexible joint (4) twists when there is a human driving force. When the torsion occurs, the magnetic flux detector 1 (15) as shown in FIG.
And the output of the magnetic flux detector 2 (16) has a phase difference. This phase shift is detected as a manual driving force, converted into an analog signal by an integration circuit, and set torque (Tref) of the assist motor.
And

FIG. 5 is a control configuration diagram of the electric assist motor. The set torque obtained by the above-described method controls the motor with the configuration of FIG. That is, since the torque of the brushless motor is proportional to the current, the error between the torque command value and the DC current is calculated as P
The error is amplified by an I error amplifier (41). This output is P
As an input of the WM (42), an output whose pulse width is controlled is obtained. This output is distributed as a drive signal of the inverter (46) by the distributor (43) in accordance with the output of the position detection (44), and controls the inverter (46).
The motor is driven as an assisting force of a manual driving force.

The control unit having the above configuration is mounted on the printed board (19) shown in FIG. 1 and attached to the horizontal axis of the column (12) together with the battery storage case 1 (21) with screws (20) as shown in the figure. Can be As for the battery, the battery storage case 2 (22) is
A storage case is formed by screw connection to (21). A detachable battery case (24) containing a battery is inserted into this.

The connection between the battery and the control printed board is made by contact between the contacts (25) and (26).

In this embodiment, the battery is attached to the tire, but can be separated from the tire. In such a case, by changing the shape of the battery storage case 1 (21), a connection cable or a connection connector necessary for connection to the battery is provided in the battery storage case 1 (21), and connected to an external battery.

[0028]

As described above, the present invention has the functions of manual driving force detection, an assist motor, a control device, and a battery serving as a power source for these devices, which are necessary for the rear wheel tire of the bicycle as an electrically assisted bicycle. By simply replacing the rear wheel, you can change to an electric assist bicycle.

Since the outer rotor type DC brushless motor and the human-powered driving unit are gearlessly connected, there is no gear loss, the efficiency is improved, and the battery can be reduced in size and weight.

Since the frame of the existing bicycle can be used as it is, the cost can be reduced due to the advantage of mass production.
By using the tire of the present invention for the rear wheel portion of an already used bicycle, it can be changed, and a resource saving effect is produced.

[Brief description of the drawings]

FIG. 1 is a sectional view of a hub showing one embodiment of the present invention.

FIG. 2 is an explanatory diagram of an arrangement relationship between a motor rotor magnet and a joint magnet.

FIG. 3 is an explanatory diagram showing a relationship between a rotor position detection signal and an inverter drive signal.

FIG. 4 is a diagram illustrating the principle of manual drive torque detection.

FIG. 5 is a control configuration diagram of a motor.

FIG. 6 is a schematic perspective view of an electrically assisted bicycle on which the tire of the present invention is mounted.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 sprocket 2 one-way clutch 3 joint 1 4 flexible joint 5 joint 2 6 rotating casing 7 magnet 1 8 magnet 2 9 axle 10 rotor core 11 stator frame 12 column 13 bearing 14 rotor magnet 15 magnetic flux detector 1 16 magnetic flux detection Device 2 17 Stator core 18 Stator coil 19 Control printed board 20 Screw 21 Battery case 1 22 Battery case 2 23 Spoke caulking hole 24 Battery storage case 25 Contact 126 Contact 2 27 Insulation bush 28 Screw 29 Drive unit 30 Frame DESCRIPTION OF SYMBOLS 1 31 Frame 2 32 Rear wheel tire 33 Rim 34 Spoke 35 Pedal 36 Chain 37 Luggage support bracket 38 Tire cover support bracket 39 Luggage platform 40 Battery 41 PI error amplifier 42 PWM 43 Distributor 44 Position detection 45 current sensor 46 inverter

Claims (4)

[Claims] 1. A one-way clutch (2) provided with a human driving force coupled to an axle (9) in a bicycle for transmitting torque obtained by manual power to a rear wheel by a transmission chain.
Disc-shaped joint provided with a through-hole for the axle (9) at the shaft end on the side opposite the sprocket (1) of the one-way clutch (2) along the axle (9) along the axle (9). 1 (3) is provided, and from the outer peripheral end of the joint 1 (3), it is turned back with the flexible joint (4) in the axial direction toward the sprocket (1), and the end face of the flexible joint (4) on the sprocket side and the outer rotor. An electric assist type bicycle tire, characterized in that a rotary casing (6) of a DC brushless type motor is connected with a joint 2 (5). 2. A motor stator frame (11) mounted on a support (12) fixed to an axle (9) as an electric assist motor.
And the rotor is supported by a bearing (13) provided on a column (12), so that the stator core (17) having an outer rotor structure for rotating the outside of the stator and a rotor magnet (14) gap. Tires for electrically assisted bicycles, characterized by a structure that can maintain a constant level. 3. The magnet 2 (8) provided on the joint 2 (5) is arranged in a similar relation to the motor rotor magnet (14), and the current of the stator coil (18) is detected by the magnetic flux detector 2 (16). A tire for an electrically assisted bicycle characterized by detecting a rotor position necessary for switching. 4. An electrically-assisted bicycle tire, wherein a battery is integrated into a drive unit hub by connecting a battery case 1 (21) and a battery case 2 (22) to a column (12).