JPH08104283A - Three-wheeled bicycle with motor assist device - Google Patents

Abstract

PURPOSE: To reduce impact by driving a rear wheel which is not driven by input among two rear wheels by an electric motor and providing a pedaling force sensor which detects large or small pedaling force due to the tension detection of a chain. CONSTITUTION: When pedaling force is 'zero', potential at B point is almost equal to potential at C point. However, if a strain gauge 19 is disconnected, potential at B point becomes lower than potential at C point. As a result, pedaling force output voltage of a differential amplifier 27 increases, and an auxiliary drive motor is rotated unnecessarily even when pedaling force is not applied. Potential at A point is monitored at all times by an amplifier 32 to prevent such an accident, and the output voltage is compared with reference voltage by a comparator 33. When it exceeds a reference value, an abnormality signal is generated. Since potential at A point is reduced when either of train gauges 19 or 20 or both of them are disconnected, an abnormality signal is generated from the comparator 33.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric drive assisted three-wheeled bicycle for driving the wheels of the three-wheeled bicycle using an electric motor.

[0002]

2. Description of the Related Art There are no examples of three-wheeled electric drive assisted bicycles, but two-wheeled ones are already on the market, and a pedaling force detection sensor is described in Japanese Patent Application Laid-Open No. 2-158485. As described above, in the method of attaching the load cell to the supporting base welded to the rear wheel frame, the vertical dimension becomes large and the chain cover is increased.
It will be difficult to store it inside, and it will be necessary to repair the sliding parts by lubricating and removing dust. In addition, the actual Kaihei 2-6
The same applies to 695. Further, JP-A-5-3101
In the method described in Japanese Patent Publication No. 77, the crank portion has a structure that is significantly different from that of a general-purpose vehicle, which increases the manufacturing cost. No similar application is found for the other sections.

[0003]

In the case of each of the above-mentioned prior arts, all of the pedal force detection sensors require repair of the sliding portion and have a large vertical dimension, so that they can be stored in the chain case. However, I needed a special car body with a structure different from that of a general-purpose car.

The present invention has been made in view of the above-mentioned problems of the prior art, and has solved all of the above problems with a simple structure.

Further, a swing resistance is reduced without using a precut tube or the like to protect the wiring of the swing portion of the vehicle body.

To reduce the impact generated by the one-way clutch by a combination of a tension wheel and a tension spring.

And when the pedal force detection sensor is out of order
It is an object of the present invention to provide a practical three-wheeled bicycle with an electric drive assist by preventing runaway of the vehicle and improving safety by disabling auxiliary drive when the power line is broken.

[0008]

According to the present invention, as a means for detecting a pedaling force, the tension of a chain is changed into a flexure of a leaf spring installed in parallel with it, and the leaf spring is further bonded to both sides of the leaf spring. The change in resistance value is replaced by a strain gauge, and it is taken out as the pedaling force output voltage of the differential amplifier from the bridge circuit shown in FIG. 8. Therefore, the displacement of the chain is only the bending of the leaf spring, and the sensor itself is mechanically damped. Since there is no moving part, no repair is required, and by installing a leaf spring parallel to the chain, the vertical dimension can be made extremely small, allowing it to be stored in the chain case Since the mounting space can be easily secured even on the car body, a general-purpose three-wheeled bicycle can be used as a base to eliminate the discomfort in appearance, and drive assistance can be achieved while reducing the cost. A three-wheeled bicycle with electric drive assist that has a structure that absorbs the impact of a one-way clutch by a car and a tension spring, and improves safety by making auxiliary drive impossible when the sensor and its related devices fail. is there.

[0009]

According to the above, a general-purpose tricycle can be used as a base to construct a tricycle with electric drive assist at a relatively low cost.

A stable drive system, a reduction in the swing resistance of the saddle, a vertically miniaturized sensor having no sliding portion, which facilitates the assembling and eliminates the need for repairs, and the sensor and its related equipment Accidents due to breakdowns can also be prevented.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 and 2 are a left side view and a plan view of an electric drive assisted three-wheeled bicycle according to this embodiment. A lead wire is wired from the sensor 1 through the protective iron pipe 8 into the battery and the lower skirt 9 of the driving force control device storage box 2. The crank driving force by human power is transmitted to the left rear wheel 7, and the auxiliary driving force by the motor is transmitted to the right rear wheel 6.

The pedal effort detected by the sensor is taken out from the differential amplifier as an output voltage corresponding to the pedal effort as shown in FIG. 8, and a necessary torque is given to the motor by a circuit not shown in the figure.

FIG. 3 is a diagram for explaining the principle of shock absorption of a one-way clutch. FIG. 4 shows the internal structure of the one-way clutch. When the motor driving force acts to rotate the one-way clutch 11 attached to the motor shaft in the direction of the arrow in FIG. 3, the pawl 16 attached to the inner ring 18 in FIG.
If there is a gap between the contact surface of the tooth cut inside the outer ring 17 and a large collision between the claw and the inner tooth of the outer ring, an impact is generated on the vehicle body. This gives an uncomfortable feeling to the rider. Is.

In order to reduce the impact, the chain 13a shown in FIG. 3 is always lightly stretched by a tension wheel 13 and a tension spring 15 attached to a swing arm 14 which freely rotates on the rear wheel gear shaft. By the way, when the claw and the inner teeth of the outer ring collide with each other, the spring expands, so that the energy of the spring is converted into the potential energy of the spring and the impact is softened.

In a currently used three-wheeled bicycle, a saddle support column 4 supporting a saddle rotates left and right with respect to a rear wheel body 6 supporting a rear wheel, and a centrifugal force of a human body generated when the saddle is tilted to bend a curve. It is supposed to be balanced against. In order to install the cable from the sensor-1 in the storage box 2 for the battery and the driving force control device mounted on the rear wheel vehicle body and wire the cable in the protective iron pipe 8, it cannot be directly connected by the iron pipe because of the swinging portion. Generally, there is a precut tube, a flexible tube, or the like for connecting such a movable part, but each of them has some bending resistance, which hinders free swinging motion. In this three-wheeled bicycle with an electric drive assist, a protective iron pipe 8 is placed in a rectangular tubular skirt 9 attached to a storage box.
It is designed so that the tip of the can freely swing.

FIG. 7 shows a sensor for detecting the pedal effort. When the treading force is 0, the contact surface of the contactor 21 is at the position indicated by the chain double-dashed line.
It is pushed up by the tension of the cord 22. The contactor 21 is fixed to the leaf spring 21a, and the other end of the leaf spring 21a is fixed by the screw 23, so that the leaf spring 21a is deformed upward depending on the magnitude of the pedaling force. A strain gauge 19 is provided on both sides of the leaf spring.
And 20 are bonded and form a part of the electronic circuit shown in FIG. 8 to convert the pedal effort into a voltage output. The sensors shown in this figure are disclosed in JP-A-2-6695 and JP-A-5-310177.
As compared with the sensor shown in FIG. 1 and the like, there is no mechanical sliding portion except for the contactor 21 that contacts the chain 22,
Since it does not require repair work such as lubrication, it is highly reliable and has a long service life. Due to its structure, it can be stored in the chain cover easily because it can be made small in the vertical dimension.

FIG. 8 shows an abnormality detection circuit for detecting an abnormality in the pedaling force detection sensor or its lead wire and an abnormality in the power source of the driving force control device to stop the driving assistance. The strain gauges 19 and 20 shown in FIG. 7 form a bridge with fixed resistors 28 and 29 as shown in FIG. 8, and the resistance change is output as a pedaling force output voltage by the differential amplifier 27.

However, for example, when the pedaling force is "0", the potential at the point B is almost equal to the potential at the point C, but when the slengage 19 is disconnected, the potential at the point B becomes lower than the potential at the point C, and as a result, the pedaling force of the differential amplifier 27 is increased. The auxiliary drive motor is unnecessarily rotated even if the output voltage rises and there is no pedaling force. In order to prevent such an accident, the potential at the point A is constantly monitored by the amplifier 32, the output voltage thereof is compared with the reference voltage by the comparator 33, and an abnormal signal is generated when the output voltage exceeds the reference value. Even if either or both of the strain gauges 19 and 20 are disconnected, the potential at the point A decreases, so that the comparator 33 issues an abnormal signal. It is also clear that the lead wire for connecting the strain gauge to the bridge is also broken.

The input connected to the + input of the amplifier 32 detects the midpoint between the + power supply and the − power supply, and when the power supply voltages have the same absolute value and the fixed resistors 34 and 35 have the same resistance value. , Its potential is usually 0V. Here, when the negative power supply voltage exceeds the limit and its absolute value drops,
The + input of the amplifier 32 rises in the plus direction from 0 V, exceeds the reference voltage of the comparator 33, and issues an abnormal signal. The abnormal signal activates the relay R37 via the transistor 36, the contact of which cuts off the input voltage of the FET 38 which drives the motor 3 and renders the motor inoperable.

In this embodiment, the decrease in the plus power supply voltage does not cause any trouble because it only causes a decrease in the pedaling force output voltage of the differential amplifier 27 and does not cause any abnormality.

The electric drive assisted three-wheeled bicycle of the present invention can be manufactured based on a general-purpose three-wheeled bicycle. Therefore, the manufacturing cost is reduced, and the saddle swing resistance is the same as that of a general-purpose vehicle. The sensor does not require any repair work except for the chain contacts, and can be stored in the chain case, so the same vehicle space as a general-purpose vehicle can be secured, and the sensor also has a safety circuit. It is possible to prevent runaway accidents even when there is an abnormality in the wiring or drive control device.

[Brief description of drawings]

FIG. 1 is a front view of a three-wheeled bicycle with an electric drive assist according to an embodiment of the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is a front view of a power transmission device from a motor to driving wheels.

FIG. 4 is a front view showing the internal structure of the one-way clutch.

FIG. 5 is a front view showing a pedaling force sensor-wiring path of this embodiment.

6 is a sectional view taken along line AA of FIG.

FIG. 7 is a sectional view of a pedaling force sensor according to this embodiment.

FIG. 8: Embodiment of auxiliary drive motor runaway prevention circuit

[Explanation of symbols] 1 pedal force detection sensor 2 battery and drive force control device storage box 3 motor 4 saddle support 6 rear wheel body 8 protective iron pipe 9 skirt 11 motor one-way clutch 13 tension Vehicle 14 Swing arm 15 Extension spring 16 Claw 17 Outer ring 18 Inner ring 19 Strain gauge 21 Contactor 36 Transistor 37 Relay 38 FET

Claims (5)

[Claims] 1. A pedaling force sensor for detecting the magnitude of pedaling force of a pedal by driving an electric motor of a rear wheel of two wheels of a three-wheeled bicycle, which is not driven by human power, and detecting tension of a chain. A three-wheeled bicycle with an electric drive assist, characterized in that a battery and a drive force control device storage box are provided in the front part of the rear loading platform. 2. A combination device of a gear and a spring for absorbing a shock generated when the chain is used for transmitting power from the motor to the drive wheels and the one-way clutch is started. A three-wheeled bicycle with an electric drive assist described in. 3. A structure of a wire protector for protecting a wire when wiring from a battery and a drive force control device storage box to a sensor via a rocking portion while wiring with a minimum rocking resistance. Item 3. A three-wheeled bicycle with an electric drive assist according to item 1. 4. A structure in which a contact arranged in parallel with a chain is provided at one end of the plate spring and the other end of the plate spring is fixed to a sensor housing, and a strain gauge is attached to both upper and lower surfaces of the plate spring. , A pedaling force detection sensor characterized by having no mechanical sliding parts other than the contacts that come into contact with the chain. 5. A strain gauge 19, 20 and a fixed resistor 28.
When the treading force detection sensor -1 is in failure, it is composed of an amplifier 32 that monitors the voltage of the bridge circuit configured by 29 and the power supply voltage of the driving force control device, and a comparator 33 that compares the amplifier output voltage with a reference voltage. When the lead wire is broken or the power supply of the driving force control device fails, an abnormal signal is issued
A circuit that prevents the motor-3 from running out of control by disabling the operation of the motor circuit.