JPH06247377A - Bicycle with electric motor - Google Patents

Abstract

(57) [Abstract] [Purpose] In a bicycle with an electric motor that has a human power drive system and an electric drive system in parallel and controls the output of the electric drive system in response to changes in the pedal power due to human power, the movement of the pedal force detection means is movable. An excessive electric drive system output does not occur even when the operation of the part is not smooth or when the modification is performed, and it is possible to prevent wasteful consumption of the battery and prevent the driving feeling from being deteriorated. [Structure] A pedaling force detecting means for detecting a pedaling force, a pedaling force increase / decrease detecting means for detecting an increase / decrease in a pedaling force measurement value obtained by the pedaling force detecting means, a cycle detecting means for obtaining a cycle of change in the increase / decrease, and comparing the cycle with a predetermined value And an abnormality determining means for determining whether or not there is an abnormality.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a driving system driven by human power and a driving system driven by an electric motor in parallel, and controls the driving force driven by the electric motor in response to changes in driving force driven by human power (hereinafter referred to as pedaling force). The present invention relates to a bicycle with an electric motor.

[0002]

2. Description of the Related Art It is known that the pedaling force is detected and the driving force of an electric motor is controlled in accordance with the magnitude of the pedaling force (Japanese Unexamined Patent Publication No. S50-125438 and Japanese Utility Model Laid-Open No. 56-76590).
No. 2-74491, etc.). That is, when the burden of human power is large, the driving force of the electric motor is also increased to reduce the load of human power.

Here, the pedaling force is usually obtained by converting the pedaling force into a mechanical displacement and electrically detecting the mechanical displacement. For example, in the case of transmitting the tread force to the rear wheels via the chain, the tension on the tension side chain can be given a displacement in the direction orthogonal to the chain running direction by a spring, and the tread force can be calculated from the amount of displacement of the chain due to the increase or decrease in the tread force. (JP-A-50-125438).

[0004]

However, in a device which detects the pedaling force by such a mechanical displacement as described above, there is a possibility that the operation may not be smooth when mud, dust, oil or the like adheres to the movable portion of the detecting means. Although such a movable part should be cleaned by daily inspection, it is usually experienced that neglecting this cleaning deteriorates the followability of the movable part to the pedal effort.

Since the actual pedaling force P periodically increases and decreases, the detected pedaling force F should also periodically increase and decrease. However, when such a mode occurs, it is considerably large even when the pedaling force is not applied. It will be judged that the pedaling force is added. Therefore, at this time, a large electric drive system output contrary to the driver's intention is generated, and there is a problem that the consumption of the battery is promoted or the driving feeling is deteriorated.
It is also possible that the driver modifies the pedaling force detection means to increase the electric drive system output.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an excessive electric drive system output may be generated even when the operation of the movable portion of the treading force detecting means is not smooth or is modified. It is an object of the present invention to provide a bicycle with an electric motor, which can prevent wasteful consumption of the battery and prevent the driving feeling from being deteriorated.

[0007]

According to the present invention, an object of the present invention is to provide a bicycle with an electric motor in which a human power drive system and an electric drive system are provided in parallel and the output of the electric drive system is controlled in response to a change in pedaling force due to human power. A pedaling force detecting means for detecting a pedaling force, a pedaling force increase / decrease detecting means for detecting an increase / decrease in a pedaling force measurement value obtained by the pedaling force detecting means, a cycle detecting means for obtaining a cycle of the increase / decrease change, and the cycle having a predetermined value. This is achieved by an electric motor-equipped bicycle, which is provided with an abnormality determining means for comparing and determining whether or not there is an abnormality.

[0008]

FIG. 1 is a side view of an embodiment of the present invention, FIG. 2 is a power system diagram thereof, FIG. 3 is a block diagram showing the function of the controller, and FIG. FIG. 5 is a diagram showing the treading force at the time of abnormality, FIG. 6 is a diagram showing the treading force at the time of abnormality, and FIG. 7 is an operation flow chart.

In FIG. 1, reference numeral 10 is a main frame, which extends obliquely downward and rearward from the head pipe 12 to the rear wheel 1.
4 axles. A seat tube 16 is fixed so as to be substantially orthogonal to the main frame 10, and a seat post 20 supporting a saddle 18 is fixed to an upper end of the seat tube 16.

At the lower part of the seat tube 16, a cylindrical portion 16a which opens downward is formed, and a permanent magnet type DC electric motor 22 is accommodated therein. A power unit 24 is fixed to the lower end of the seat tube 16. The power unit 24 includes a bottom bracket case (hereinafter referred to as BB case) 26 and a rear stay 28 extending rearward from the BB case 26, and the rear wheel 14 is fixed to a rear end of the rear stay 28. A drive shaft 30 (see FIG. 2) is inserted into the right rear stay 28.

A crankshaft 32 is inserted through a BB case 26 of the power unit 24, and cranks 34 are fixed to both ends thereof. The crank 34 has a crank pedal 36,
36 is attached.

The left end of the axle 38 of the rear wheel 14 is fixed to an end plate 28a fixed to the left rear stay 28,
The right end of the axle 38 is fixed to a bevel gear case (not shown) fixed to the right rear stay 28. Axle 38
A hub (not shown) is rotatably held in the hub, and the rotation of the drive shaft 30 is transmitted to the hub via a bevel gear mechanism and a one-way clutch 42 (FIG. 2).

In the power unit 24, the rotation of the crank shaft 32 is transmitted to the drive shaft 30 via a one-way clutch 44 (FIG. 2).
Bevel gears (not shown) are installed inside. A planetary gear mechanism is interposed between the crank shaft 32 and the drive shaft 30.

In this planetary gear mechanism, pedaling force is input from the planetary gear, and pedaling force is output from the ring gear to the drive shaft 30. Then, the pedaling force F is detected by detecting the torque applied to the central sun gear with a potentiometer 46 as a pedaling force detecting means. Motor 2
The rotation of 2 is transmitted to the drive shaft 30 via the one-way clutch 48 and the speed reducer 50.

In FIG. 1, reference numeral 52 is a rechargeable battery such as a lead acid battery, 54 is a controller, which are housed between the head pipe 12 and the seat tube 16 of the main frame 10. In FIG. 1, reference numeral 56 is a vehicle speed sensor for obtaining the vehicle speed S from the rotational speed of the front wheels 58.

The pedaling force F detected by the potentiometer 46 is input to the controller 54, which controls the motor current based on the pedaling force F to generate a motor output, that is, a motor torque T _M.

The controller 54 is constructed as shown in FIG. The motor 22 and the battery 52 form a closed circuit together with the switching circuit 60, and this closed circuit serves as the main circuit 62. The switching circuit is composed of a thyristor bridge and a transistor bridge. A flywheel diode 64 is connected in parallel to the motor 22, and a shunt 66 for current detection is attached to the main circuit 62.

Reference numeral 68 is a CPU, and 68a is a memory. C
The PU 68 has a function of the traveling control unit 68A, and outputs (torque) T _{M of the} motor 22 based on the pedaling force F, the vehicle speed S, and the like.
The command value i of is output. That is, the command value p is output so that the output (torque) T _M of the motor 22 is periodically increased / decreased in synchronization with the periodic increase / decrease of the pedal effort F. In addition, constant vehicle speed S
If so, the motor output T _M may be limited to limit the vehicle speed S.

Reference numeral 70 denotes a gate circuit, which outputs a gate signal g whose duty ratio changes in accordance with a command value i supplied from the CPU 68. That is, when the command value i increases the motor output T _M , the gate signal g (on time)
The value of / (off time + on time) (called duty) is increased.

The gate signal g output by the gate circuit 70 based on the command value i is sent to each switching element of the switching circuit 60 to selectively turn on / off each switching element.

In FIG. 3, reference numeral 72 is a pedaling force increase / decrease detecting means for detecting the time derivative dF / dt of the pedaling force F. In the pedal effort increase / decrease detecting means 72, as shown in FIG. 4, the measured value F of the pedal effort F detected by the potentiometer 46 at every time dt.
difference _a, i.e. the last detected measured value (previous value) F (t
-Dt) and the measurement value (next value) F detected next.
The sign of the difference from (t) is obtained and the flag is output. Therefore, the sign of this difference is + while the measured value F _{a of} pedaling force is increasing, and is − while it is decreasing, and it is 0 if there is no change in this difference, so the flag is as shown in FIG. When the difference changes from 0 to +, it changes from − to +, and when the difference changes from 0 to −, it changes from + to −.

In FIG. 3, 74 is a period detecting means,
A cycle T for increasing / decreasing the pedaling force F is obtained. Actually, as shown in FIG. 4, half the period T / 2 is obtained by measuring the time from the time t ₁ when the flag changes from + to − to the time t ₂ when − changes to +.

Reference numeral 76 is an abnormality determining means, and the calculated period T
Or check if T / 2 is in the proper range,
If it is outside the proper range, it is determined that there is an abnormality, and the drive of the motor 22 is stopped. Actually, T / 2 is compared with the longest limit that can be taken in the normal state, and if it is less than or equal to the longest limit, it is determined to be normal. For example, in FIG.
When the cycle T or its half T / 2 becomes longer than the longest limit, it is determined to be abnormal, and the power assist by the motor is stopped immediately after the cycle exceeds the longest limit.

In this embodiment, the measured value F _a of the pedal effort is not used as the pedal effort F to determine the motor output T _M , but the difference (F) between the measured value T _a of the pedal effort and the predetermined lower limit value F _m of the pedal effort.
_a− F _m ) is obtained as the pedaling force instruction value Fi, and this instruction value F
_The motor output T _M is calculated based on _i . 78 of FIG.
Is a pedaling force instruction value calculation means for performing this calculation.

The lower limit value of the pedaling force F _m is set near the upper limit of the measured value of the pedaling force F _{a in} the normal operating range immediately after the power is turned on, and is set to the minimum value of the measured value of the pedaling force F _a in each cycle as the vehicle travels. Rewrite it so that it gradually approaches. This calculation is performed by the pedaling force lower limit value calculation means 80. The circle mark in the column for comparing the pedaling force lower limit values in FIG. 4 indicates the timing of this rewriting.

The difference between the thus depressing force limit value F _m (F _a -
By obtaining the motor output T _M using F _m ) as the pedaling force instruction value F _i , it is possible to prevent the motor output T _{M from} becoming excessively large even if the excessively large pedaling force measurement value F _a is input. This is because the pedaling force lower limit value F _m is a large value at first and is rewritten thereafter to converge near the minimum value of the pedaling force measurement value T _a . Therefore, as shown in FIG. 6, if the pedaling force measurement value F _a is smaller than the pedaling force lower limit value F _m and does not change constantly, the pedaling force instruction value F _i becomes negative and is abnormal.

Next, the operation will be described with reference to FIG. First C
The PU 68 sets the flag to + (step 100), sets the pedaling force lower limit value F _m (step 102), and performs other initialization processing. Then, the pedaling force measurement is started for a certain period of time d.
reading writing the treading force measuring value F _a per t (step 104).
In the pedal effort instruction value calculation means 78, the pedal effort instruction value F _i = (F _a −
The calculation of F _m ) is constantly repeated at intervals of a predetermined time dt (step 106). The traveling control means 68A controls the motor output T _M based on the pedaling force instruction value F _i .

The pedaling force increase / decrease detecting means 72 obtains the difference between the pedaling force measurement values F _a during the time dt (step 108), and if the difference is decreasing, it is determined that the difference is negative (step 110). It is checked whether it matches the set flag (step 112). In this case, since they do not match, the flag is rewritten from + to − (step 11
4). Then, the cycle detecting means 74 starts time counting by the counter (step 116).

Then, returning to step 106, the pedaling force instruction value F _i is rewritten and the motor output T _M is controlled, while the difference is obtained after the time dt (step 108).
If the pedaling force is decreasing, the difference is negative (Step 11
0), because it matches the flag (-) (step 11
2) Add a constant value to the counter (step 11)
8). The abnormality determining means 76 compares the integrated value of the counter with the longest limit, and if it is less than or equal to the longest limit (step 120), returns to step 106. While the pedaling force is decreasing, the difference is negative and coincides with the flag (-) (steps 108, 110,
112), during which the counter is incremented. If the integrated value of the counter exceeds the longest limit while the pedaling force is decreasing, it is determined that there is an abnormality, the flag is changed to + (step 122), the counter is reset to 0 (step 124), and the motor 2
The assistance by 2 is stopped (step 126).

If the pedaling force changes to increase before the integrated value of the counter corresponding to the cycle T or T / 2 reaches the longest limit, the difference becomes positive (steps 108 and 128), and the flag immediately before that is −, so that both are If they do not match (step 130), the flag is rewritten to + (step 1)
32). Then the counter is reset to 0 (step 134), it determines whether it is necessary to rewrite the depression force limit value F _m (step 136).

Rewriting of the pedal effort lower limit value F _m is performed near the minimum value of the pedal effort F as described with reference to FIG. 4, and the measured pedal effort value (previous value) F _a near this value must be larger than the pedal effort lower limit value F _m. If you do not rewrite. If smaller the pedaling force measurement value seeking the arithmetic mean of the (previous value) F _a, a pedal pressure lower limit value, this is a new pedal force limit value F _m (step 138). Thus pedaling force measurement value F _a minimum pedal force limit value F _m between less than the repeats rewriting to reduce gradually the depression force limit value F _m for each cycle.

In the present embodiment, the time period is from the time t ₁ when + changes to − to the time t ₂ when − changes to +, but the present invention is not limited to this. Time t ₂
To the time point t _{1 of the} next cycle, or the time in the constant angle range of the crankshaft may be measured.

Further when rewriting of pedal force limit value F _m may also be determined depression force limit value F _m by using a weighted average of the other ratios since in a simple arithmetic average of the F _a and F _m.

[0034]

As described above, the invention of claim 1 monitors the increase and decrease of the pedaling force measurement value, and when the increase / decrease cycle exceeds a predetermined value (longest limit), it is determined that there is an abnormality.
Even if the pedal effort detecting means has a malfunction or is modified, the motor output does not become excessive, the battery is not wastefully consumed, and the driving feeling is not deteriorated.

[Brief description of drawings]

FIG. 1 is a side view of an embodiment of the present invention.

[Fig. 2] Power system diagram

FIG. 3 is a block diagram showing functions of a controller.

[Fig. 4] An explanatory diagram of operations in a normal state

FIG. 5 is a diagram showing an example of a pedaling force measured value at the time of abnormality.

FIG. 6 is a diagram showing another example of the tread force measurement value at the time of abnormality.

[Fig. 7] Operation flow chart

[Explanation of symbols]

14 rear wheel 22 electric motor 36 crank pedals 46 potentiometer 54 controller 68 CPU 72 pedal force increases or decreases detection means as pedal force detection means 74 pedal force cycle detecting means 76 abnormality judgment means F pedal force F _a pedaling force measurement value

Claims (1)

[Claims] 1. A pedaling force detecting means for detecting a pedaling force in a bicycle with an electric motor, wherein a human-powered driving system and an electric driving system are provided in parallel, and the output of the electric driving system is controlled in response to a change in the pedaling force due to human power. A pedaling force increase / decrease detecting unit that detects an increase / decrease in a pedaling force measurement value obtained by the pedaling force detection unit; a cycle detecting unit that obtains a cycle of the increase / decrease change; and a presence / absence of abnormality by comparing the cycle with a predetermined value. A bicycle with an electric motor, comprising: an abnormality determining means.