JP2002321680A - Operating device of power-assisted bicycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve problems that regenerative power is small, and the reduction effect of the capacity of a power source is small in an power-assisted bicycle having a driving part on a transmission mechanism behind a one-way clutch. SOLUTION: An outer rotor type permanent magnet synchronous motor is used for a drive motor, a switching element to be ON-OFF controlled to supply the regenerative power to a battery is provided between the battery and a forward/reverse switchable drive device, and a diode is connected to this switching element in a reverse parallel manner.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrically assisted bicycle, and more particularly to an electrically assisted bicycle with a reduced battery capacity.

[0002]

2. Description of the Related Art An electrically assisted bicycle has two driving forces, one of which is transmitted from a petal through a chain to a rotating side of a casing through a chain, and the other is a driving force for rotating wheels. One is configured to detect a torque applied to a petal, rotate a motor with a torque of the same magnitude as the torque, and drive wheels through a speed reduction mechanism. Although various types of such electrically assisted bicycles have been proposed, all of them have been arranged with a motor in the drive unit, and the speed of the drive motor has been increased with the aim of reducing the size and weight of the structure. The required torque is obtained by decelerating with a pulley. Further, a drive unit and a tire unit are connected via a chain and a one-way clutch, and a deceleration mechanism is provided even when a drive motor is provided in the tire unit.

[0003]

The conventional electric assist type bicycles cannot be combined into a compact mechanism because all of them have a speed reduction mechanism, and it is necessary to greatly change the basic structure of a normal bicycle. As a result, the cost is high, and when the voltage charged in the battery runs out, the required manual driving force increases.
Further, as the drive motor, a DC motor having a brush of about 200 W and a motor efficiency of 50 to 60% is employed, and the speed reduction mechanism is employed as described above. For this reason, even if the drive unit is provided on the transmission mechanism provided after the one-way clutch provided between the transmission mechanism between the manual drive unit and the motor drive unit to regenerate, the amount of regenerative power is small and the power supply capacity is reduced. Is less. Furthermore, there is a problem that traveling without assist is difficult due to a gear loss in the speed reduction mechanism, and there is a problem that the assist force during traveling on level ground cannot be reduced.

An object of the present invention is to provide a bicycle which employs a magnet-type synchronous motor as a drive motor and can run a long distance with a small power supply without providing a reduction mechanism such as a gear. .

[0005]

SUMMARY OF THE INVENTION A first aspect of the present invention is a motor-assisted bicycle having a drive device that is switchable so that current flows between a battery and a drive motor in both forward and reverse directions. A first diode for providing a diode connected in a forward direction to the flow path and controlling regenerative power between the drive device and the battery;
And the drive motor is an outer rotor type permanent magnet synchronous motor.

A second aspect of the present invention is to provide a capacitor in place of the battery, connect a series circuit of a reactor and a second switching element in series with the capacitor, and form a bridge between the reactor and the second switching element. The diode is connected between a point and a drive device.

[0007]

FIG. 1 shows an embodiment of the present invention. 1 is a drive motor, and this drive motor 1
An outer rotor type permanent magnet synchronous motor is used. Reference numeral 2 denotes a drive device, which has a conversion function in a forward direction and a reverse direction and is configured by a transistor or the like. Reference numeral 3 denotes a battery, 4 denotes a switching element including a transistor or the like, 5 denotes a reactor, 6 denotes a capacitor, and 7, 8 denote diodes. In charging the battery 3 in this circuit, the capacitor 6 is first charged from a charging power supply (not shown), and when the voltage reaches, for example, 30 V, the switching element 4 is turned on to charge the battery. Charging is completed when the charging voltage reaches, for example, 28 V, but power is supplied from the capacitor 6 when the bicycle is running, and is supplied from the battery 3 via the diode 7 when the voltage of the capacitor 6 decreases. Drive motor 1
Is in the powering state, the drive device 2 becomes an inverter,
Electric current flows to the motor 1 through the capacitor 6 and the drive device 2.

When the bicycle runs downhill, the driving motor 1
To operate as a generator, the drive device 2 becomes a converter, charges the capacitor 6 with the acceleration energy through the motor 1 and the drive device 2, and turns on the switching element 4 when the charged voltage exceeds a certain value. To charge the battery 3 via the reactor 5.
In this way, the acceleration energy is absorbed by the power supply, the braking torque is generated, and the power supply is charged, so that long-distance running is possible even if the battery capacity as the power supply is small. In addition, even when there is a large regenerative current, the battery 6 is charged with a constant current by controlling the switching element 4 after storing the energy once by the capacitor 6, so that the excessive current charging is not performed.

FIG. 2 shows another embodiment, and FIG.
The difference is that instead of the battery 3, the capacitor 1
0, the diodes 11 and 12 for blocks are provided along with charging from the charging power supply, and the second switching element 9 is provided. As a power supply for charging, the power is rectified by a rectifier from an AC power supply of 100 V,
The converted DC current is applied to the diode 12, and on condition that the first switching element 4 is turned on, the capacitor 6 is charged via the diode 12, the switching element 4 and the diode 7, and the reactor 5 is charged. , The capacitor 10 is also charged. When the bicycle is running, power is supplied from the capacitor 6, and when the voltage of the capacitor 6 decreases, the switching element 9 is turned on / off to supply the power via the capacitor 10, the reactor 5 and the diode 7, and the voltage of the capacitor 6 is reduced by 24
Hold at ~ 30V.

FIG. 3 is a view showing the configuration of a drive unit installed on the rear wheel of a bicycle. Reference numeral 20 denotes an axle, reference numeral 21 denotes a bearing fitted to the axle, and an outside of the bearing is integrated via a clutch 22. The sprocket 23 is attached rotatably. Although not shown, a chain connected to a petal is stretched on the sprocket 23. Reference numeral 24 denotes a second joint, which is formed in a disc shape and has a hollow portion, a part of which is connected to the clutch 22, and a spoke hole 2 on which a spoke of a wheel is mounted outside.
5 are provided. In the hollow portion of the joint 24, a support plate 26 fixed to the axle 20 is provided so as to extend, and a stator core 27 is provided along the circumference of the tip thereof.
A winding 28 is wound around the stator core 27. Permanent magnets 29 are alternately arranged along the circumference of the stator core 27 with a gap G alternately along the circumference to form a rotor. The outer rotor type permanent magnet synchronous motor 1 shown in FIG.

Reference numeral 30 denotes a printed board.
Are mounted with circuit components of the conversion unit 4 and the control unit 6, and are fixed to the support plate 26 by bolts or the like. 31 is a first joint which is fixed to the side surface of the clutch 22 and
A flexible joint 32 is interposed between the second joint 24 and the second joint 24. Reference numeral 33 denotes a Hall element disposed on the support plate 26. A magnet is disposed on the first joint 31 on the surface facing the Hall element 33, and the position for the A phase is detected. 34 is B
This is a phase detection magnet. 35 and 36 are bearings, respectively.

The drive unit constructed as shown in FIG. 3 is driven by a sprocket 23 and a clutch 22 by stepping on a petal.
And a driving force is transmitted to the second joint 24, which rotates while being supported by the respective bearings 21, 35, 36. Due to this rotation, the permanent magnet 29 fixed to the joint 24 also rotates, and the stator winding is determined by the rotor position by utilizing the attraction and repulsion generated between the rotating permanent magnet 29 and the stator winding 28. The rotation is continued by switching the direction of the current flowing through 28.

By the way, in an assisted bicycle,
As shown in FIG. 4, the assist rate by the motor torque is defined as 1 or less up to 15 km / h, and is 15 to 24 km / h.
During this period, the torque is temporarily reduced, and assist is prohibited at 24 km / h or more. Although not shown in the drawing, the control circuit of the drive device 2 has an ASR (automatic speed control) function for switching to a constant speed at a speed of 15 km / h or more by a speed detection unit. The command calculation unit has an ATR (automatic torque control) function for switching to a constant torque at 15 km / h or less.

When the energy during uphill and downhill traveling is calculated according to the above rules, the drive motor 1 assists half of the required power during uphill traveling. Further, the acceleration energy on the downhill is obtained by reducing the loss due to the rolling resistance and the windage damage to the human body from the electric power required for the uphill running. That is, if the efficiency of the motor 1 and the drive device 2 is neglected, the power can be saved by 50% when climbing a hill and by nearly 100% when descending a slope. Can be made extremely small.

In view of the above, in the present invention, an outer rotor type in which the drive unit is constructed as shown in FIG. 3 and a manual drive force is connected via a chain, a one-way clutch and a flexible joint without providing a speed reduction mechanism. Motor is an assist motor, so human-powered driving force,
The driving force can be transmitted to the traveling tire with very little loss in both the motor driving force. Therefore, in flat-land running, the vehicle can be driven only by a small amount of manual driving except during start-up and acceleration, and in downhill running, the drive motor is operated as a generator to reduce acceleration energy in downhill. The circuit of the present invention absorbs the electric power in the power supply to generate a braking torque and charges the power supply battery (or capacitor). This makes it possible to run long distances with a small battery capacity.

Next, specific battery capacity and capacitor capacity when the above operation method is adopted will be examined and examined. According to JISD9207,
The running resistance F (N) after reaching the constant speed is expressed by the following equation.

F (N) = R + 0.027 V ² +9.8 W sin θ where V: speed (km / h), W: standard value of equivalent inertial mass (kg), θ: uphill angle (°), R: rolling resistance In (N), the rolling resistance per wheel not installed on the roller of the chassis dynamometer is set to 2.6.
0.027: Air resistance coefficient [N / (km / h) ² ] FIG. 5 shows a pattern (W = 90 k) for calculating running resistance.
g), on a general road, when θ = 0, V = 15 km / h and F = 8.7 (N) When θ = 2 °, V = 10 km / h and F = 36.1.
(N) When θ = −2 °, V = 15 km / h and F = −22.
1 (N) When traveling on a sloping road with θ = 4 ° (V = 10 km / h), when climbing a hill F = 2.6 + 0.027 × 10 ² + 9.8 × 90 s
in4 = 66.8 (N) Downward F = 2.6 + 0.027 × 10 ² + 9.8 × 9
0 sin (−4) = − 56.2 (N) The traveling power P is: P = 1.027n × 1 / 9.8F × γ where n is the wheel rotation speed, and n15 = 15000m / 60 (π × 26 × 0.025
4) = 120.5 (rpm) n10 = 80.4 (rpm
m) Also, γ is a wheel radius, and γ26 = 26 × 0.254 / 2 = 0.33 (m) for a tire diameter of 26 inches (1) Since the assist ratio is set to 1 at the time of driving, the required capacity is １ ／. The traveling electric power on the general traveling road at the time of is as follows.
7 × 0.33) × 1/2 = 18.2 W Running power at θ = 2 ° Pθ2 ° = (1.027 × 80.4 × 1 / 9.8 × 3)
6.1 × 0.33) × 1/2 = 50.2 W Running power at θ = −2 ° Pθ−2 ° = 1.027 × 120.5 × 1 / 9.8 ×
(-22.1) × 0.33 = 92 W (2) Calculate the power supply capacity. In calculating the power supply capacity, it is necessary to take into account the efficiency of the motor and the drive device. Therefore, here, the motor efficiency ηM = 0.82 and the conversion efficiency ηS of the drive device = 0.93.

When driving PA = Pθ / ηM · ηS Pθ0A = 18.2 / 0.82 × 0.93 = 24 W Pθ2 ° A = 50.2 / 0.82 × 0.93 = 66 W When absorbing PB = Pθ From ηM · ηS, Pθ-2 ° B = 92 × 0.83 × 0.93 = −71 W Therefore, the power consumption P on a general traveling road is obtained by multiplying the above value by the traveling time. (24 × 1 / 15H) × 3 + 66 × 1 / 10H-7
1 × 1 / 15H = 6.6 W / H (3) The electric power at the time of going up a hill on the traveling road with θ = 4 ° is PA (θ = 4) = (1.27 × 80.4 × 1 / 9.8 ×
66.8 × 1.33) × 1/2 × 1 / 0.82 × 1 /
0.93 = 122W The electric power at the time of the down is PB (θ = −4 °) = 1.027 × 120.5 × 1 /
9.8 x (-56.2) x 0.33 x 0.82 x 0.9
3 = 178 W Therefore, the power consumption at a 4 ° gradient is: P = 122 W × 1 / 10−178 × 1/15 = 0.33
W / H.

[0019]

As described above, according to the present invention, since the drive motor regenerates electric power as an outer rotor type permanent magnet synchronous motor, it is possible to reduce the size by eliminating the speed reduction mechanism. The driving force can be transmitted to the traveling tire with very little loss. Therefore, since the vehicle can be driven only by small human power except for starting and accelerating during flatland running, an extremely small power source capacity is sufficient by eliminating assist during steady running on flat ground. In addition, during downhill traveling, the drive motor is operated as a generator to absorb acceleration energy on downhill into the power source, generate braking torque, and charge the battery. From the above, it is possible to obtain an electric assist bicycle that can run for a long distance with a small battery capacity. In addition, an electric double-layer capacitor can be used as a power source, and an extremely convenient electric assist bicycle that can be charged for a long time and in a short time can be provided.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing another embodiment of the present invention.

FIG. 3 is a configuration diagram of a driving unit according to the present invention.

FIG. 4 is an assist rate-speed characteristic diagram.

FIG. 5 is a running resistance calculation pattern diagram.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Drive motor 2 ... Drive device 3 ... Battery 4 ... First switching element 5 ... Reactor 6 ... Capacitor 7, 8, 11, 12 ... Diode 9 ... Second switching element 10 ... Capacitor

Claims (2)

[Claims] 1. An electric assist bicycle having a drive device configured to allow current to flow between a battery and a drive motor in both forward and reverse directions, comprising: a diode connected in a forward direction to an electric path of the battery and the drive device; A driving device for an electrically assisted bicycle, wherein a first switching element for controlling regenerative power is connected between a drive device and a battery, and the drive motor is an outer rotor type permanent magnet synchronous motor. 2. A capacitor is provided in place of the battery, a series circuit of a reactor and a second switching element is connected in series with the capacitor, and a bridge point between the reactor and the second switching element is connected to a drive device. 2. The device according to claim 1, wherein the diode is connected to the power supply.
The driving device of the electric assist bicycle according to the above.