JP3468843B2 - Bicycle with electric motor and control method therefor - Google Patents

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). and an electric motor with a bicycle that was so
It relates to the control method .

[0002]

2. Description of the Related Art It is known that a pedaling force is detected and the driving force of an electric motor is controlled according to the magnitude of the pedaling force (Japanese Utility Model Laid-Open No. 56-76590, JP-A-2-74491). 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.

[0003]

2. Description of the Related Art Here, since the driving force (pedal force) of human power is input from the crank pedal, it changes with a half rotation cycle of the crank shaft. This is because the pedal effort becomes almost zero when the crank pedal reaches the top dead center or the bottom dead center.
In order to take advantage of the bicycle specific driving sensation, motor drive force by detecting the pedaling force F _L which varies periodically F _M may be desirable to periodically increase and decrease. Conventionally, these ratios F _M / F _L are defined as an auxiliary ratio η, and the auxiliary ratio η is controlled to be constant.

[0004]

[Problems of the prior art] When the assist ratio is constant, the assist ratio should be set to be optimum in the medium speed range by giving importance to the driving feeling during the medium speed running which is most frequently used. become. However, in order to suppress the consumption of the battery and to use the electric motor assistance as long as possible, it is necessary to set the assistance rate as small as possible. Further, in order to take advantage of the riding feeling like a bicycle, it is desirable to make this auxiliary ratio as small as possible.

However, if the subsidy rate is reduced in this way,
When the vehicle speed is low, including starting , the motor assistance becomes insufficient, so that the vehicle tends to wander, and when starting , it takes a long time to reach a stable and self-sustaining vehicle speed.
For this reason, there is a problem that it is difficult to ride when a driver with weak leg strength such as an elderly person gets on or starts up on a slope.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is possible to sufficiently reduce the assist rate by the electric motor in the most frequently used medium speed range to suppress the consumption of the battery and to provide a bicycle-like running feeling. On the other hand, stable running at low speed
A first object of the present invention is to provide a control method for a bicycle with an electric motor that can be performed by an elderly person or a person with weak leg strength and can easily start on a slope. Also provide this bicycle with electric motor
Is the second purpose.

[0007]

According to the present invention, a first object is to control a bicycle with an electric motor in which a human power drive system and an electric drive system are provided in parallel and the electric drive power is changed in response to a change in pedaling force due to human power. in the method for detecting the depression force and the vehicle speed, or starting
In the low speed range up to at least the speed at which stable self-sustaining travel is possible, at least in the low speed range, the auxiliary ratio of the electric driving force to the human driving force during start is maximized ,
The assist rate is smoothly reduced from the assist rate in the low speed range
Of being achieved by the control method of the bicycle with an electric motor, characterized in that it has a substantially constant value and to so that lower subsidy rate.

A second object of the present invention is to provide a pedal with an electric motor in which a human power drive system and an electric drive system are provided in parallel, and the electric drive power is changed in response to a change in the pedal power due to human power. At least stable and self-supporting running is possible after the start of the bicycle.
Starting determination means for detecting a low speed range up to the speed at which it becomes effective,
Based on the output of the start determination means in the low speed range, at least the auxiliary ratio of the electric driving force to the human driving force during starting is set.
Set the maximum to the following level and set the auxiliary ratio in the medium speed range to the auxiliary ratio in the low speed range.
Approximately lower than the auxiliary rate in the low speed range by smoothly decreasing from the rate
The present invention is achieved by a bicycle with an electric motor, comprising: a traveling control unit that controls an electric drive system so as to keep a constant value .

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a side view of an embodiment of the present invention, FIG. 2 is a developed view of II-II line thereof, FIG. 3 is a sectional view taken along line III-III of FIG. 1, and FIG. 5 is a block diagram showing the function of the controller, and FIG. 6 is a diagram showing an example of the control characteristic of the auxiliary rate.

In the bicycle of this embodiment, as shown in FIG. 1, a power unit 12 is fixed to a main frame 10 having a substantially U shape from the rear side. The main frame 10 includes a head pipe 14, a down tube 16 extending obliquely downward and rearward therefrom, a seat tube 18 rising from the rear end of the down tube 16, a steering handle 20 rotatably held by the head pipe 14, and Front fork 22,
It has a front wheel 24 held by the front fork 22 and a saddle 26 held by the upper end of the seat tube 18.

The power unit 12 has a transmission case 30 made of aluminum casting integrally formed with a cantilevered rear arm 28.
A rear wheel 32 held at the rear end of the case 30, a pair of left and right crank arms 34, 34 (see FIG. 2) attached to the front of the case 30, and an upper surface of the front of the case 30. It has an electric motor 36 (see FIG. 3) installed therein and batteries 38, 38 mounted above the motor 36.

The power unit 12 is bolted to three brackets 40, 42 and 44 fixed to the main frame 10. That is, the front portion of the transmission case 30 is fixed to the brackets 40 and 42, and the battery holding frame 46 located at the upper end of the motor 36 is fixed to the bracket 44. Further, as shown in FIG. 1, the power unit 12 includes a controller 48, a circle lock 50, and a brake 52.
Is installed.

The transmission case 30 is formed in a box shape as shown in FIGS. 2 and 3, and a crank shaft 54 penetrates the case 30 and the crank arms 34, 34 are fixed to both ends thereof. In the case 30, a resultant shaft 56 is rotatably held behind the crankshaft 54 obliquely above. The rotation of the crankshaft 54 is caused by the toothed belt 58.
6. A one-way clutch 62 is mounted on the pulley 60 on the crankshaft 54 side around which the belt 58 is wound, as shown in FIG. This clutch 62
Transmits the rotation of the crankshaft 54 to the pulley 60, but does not transmit the rotation in the opposite direction.

A tread force sensor 64 is attached to the tight side of the belt 58 as shown in FIG. The depression force sensor 64 is provided with an idle roller for absorbing the slack rolling contact with the belt 58, it detects the tension i.e. pedaling force F _L of the belt 58 from the displacement amount of the idle roller.

A large reduction gear 68 is attached to the resultant shaft 56 via a one-way clutch 66, and a small reduction gear 70 driven by the motor 36 is meshed with the gear 68. Therefore, the rotation of the motor 36 is limited to the gears 68, 70.
Is transmitted to the resultant force shaft 56 via a speed reducer 72 and a one-way clutch 66. In addition, from the resultant shaft 56 to the motor 36
Transmission of rotation to the clutch is interrupted by the clutch 66.

A drive sprocket 7 is provided at the left end of the resultant shaft 56.
4 is integrally fixed, and a driven sprocket 80 is attached to the hub 76 of the rear wheel 32 via a one-way clutch 78. A chain 82 passing through the inside of the rear arm 28 of the case 30 is wound around these sprockets 74 and 80. The hub 76 may have a transmission built therein.

In FIG. 4, reference numeral 84 is a vehicle speed sensor, which can be provided in the hub 86 of the front wheel 24 shown in FIG. 1, for example. A pedal force F _L to the depression force sensor 64 detects, from the vehicle speed S that the vehicle speed sensor 84 detects is input to the controller 48. The controller 48 controls the motor current in response to changes in the pedal force F _L, and controls the output F _M of the motor 36. Since the reduction ratios of the human power drive system and the electric drive system are different, the pedaling force applied to the crank arm 34 and the motor 3 are different.
Even if the output of 6 is the same, the driving force at the rear wheel 32 is different. Here To unaffected by differences in the speed reduction ratio, pedal force F _L and the motor output F _M each rear wheel 32
Represents the driving force applied to.

The controller 48, as shown in FIG.
PU 90, memory 92, motor power control unit 94,
Other various devices are provided. The CPU 90 has a traveling control means 96, a start determination means 98, and various control means having other functions.

The traveling control means 96 outputs a motor output (torque) F _M = ηF _L which changes in synchronization with the cycle of the pedal effort F _L based on the pedal effort F input from the pedal 36.
That P which changes the duty ratio corresponding to the pedal force F _L
A WM (pulse width control) signal is output to the motor power controller 94. Here, the auxiliary rate η changes as shown in FIG. 6, and this point will be described later. Motor power control unit 94
Supplies a motor current that turns on and off at this duty ratio to the motor 36 to generate a predetermined output F _M.

The start determination means 98 determines the speed range from the start of the bicycle to the speed at which stable independent driving is possible as a low speed range. In this embodiment, based on the vehicle speed S which is the output of the vehicle speed sensor 84, the range during acceleration (point a → b in the figure) from S≈0 to about 6 km / h as shown in FIG. ). In this case
Discriminates only the low speed range at the time of start (L), the deceleration immediately before stopping is not necessary to determine this low speed range (L). Figure 5
Reference numeral 100 is a main switch, and 102 is a brake switch.

In the traveling control means 96, the auxiliary ratio η is shown in FIG.
As shown in, the vehicle speed S is changed. That is, when the start determination means 98 determines that the vehicle is in the low speed range (L) during start, the traveling control means 96 sets the assist ratio η to the assist ratio η _M (for example, 1.0) in the medium speed range (M). Increase about 3 times. Here, the middle speed range (M) is in the range of about 6 to 15 km / h (point b → d in the figure), and the middle speed range (M) is in the initial stage (about 6 to
In the range of 8 km / h) (point b → c in the figure), the auxiliary ratio η smoothly changes from the low-speed auxiliary ratio η _L ≈3.0 to the medium-speed auxiliary ratio η _M ≈1.0.

When the vehicle speed S exceeds 15 km / h, the vehicle enters the high speed range (H), and in this speed range (point d → e in the figure), the auxiliary ratio η _H gradually decreases as the vehicle speed S increases. This subsidy rate _H
May decrease linearly as shown in FIG. 6, but may decrease non-linearly.

In this way, the starting determination means 98 determines the low speed range (L, point a → b) at the time of starting, and the traveling control means 96 increases the auxiliary ratio η _L by about 3 times in this range. The acceleration performance of the vehicle is improved, and the vehicle speed (for example, about 6 km / h) that enables stable self-sustaining travel is quickly reached. For this reason, even when a person with weak leg strength rides or starts on a slope, the period during which the vehicle body fluctuates at the time of starting is shortened, and stable starting is possible.

In this embodiment, since the starting determination means 98 does not determine the low speed range (L) during deceleration, the traveling control means 96 uses the auxiliary rate η _L0 at this time as the auxiliary rate η in the medium speed range (M).
It is kept the same as _M (point c → f in FIG. 6). Therefore, when decelerating to stop the vehicle, the auxiliary ratio η does not increase, and the motor output F _M does not unnecessarily increase. The determination as to whether or not the vehicle is decelerating can be made by monitoring the vehicle speed S, but it may also be made from the fact that the brake switch 102 is turned on (the brake is being operated).

In the above embodiment, the starting discriminating means 98 discriminates the low speed region (L) during starting and does not discriminate the low speed region (L) during deceleration. Therefore, the consumption of the battery can be suppressed. However, the present invention includes the one that always increases to the same auxiliary ratio η _L in the low speed range without distinguishing between the start and the deceleration.
Here, this same auxiliary ratio η _L is lower than the auxiliary ratio η _{M in the} medium speed range.
Of course, it should be large. Further, in order to limit the inrush current of the motor 36 at the time of starting, a soft start circuit may be provided to gradually increase the auxiliary ratio η _L at the beginning of the low speed range (L) as shown by a virtual line in FIG.

FIGS. 7, 8 and 9 are diagrams for explaining different discrimination algorithms of the starting discrimination means 98. In the explanatory view of FIG. 7, the starting time point g is obtained from the vehicle speed S, and from this time point g to a time point h when a certain time t ₀ elapses is defined as a low speed range (corresponding to points a → b in FIG. 6). In the explanatory view of FIG. 8, the starting time point i is obtained from the vehicle speed S, and from this time point i to the time point j at which the vehicle has traveled the constant travel distance D ₀ is defined as a low speed range (corresponding to points a → b in FIG. 6). is there.

In the explanatory view of FIG. 9, the starting time point k is detected from the acceleration A of the vehicle body, and the low speed range (corresponding to points a → b in FIG. 6) is set up to the time point 1 when the vehicle speed S becomes constant. . Here, the acceleration A can be obtained by time-differentiating the vehicle speed S detected by the vehicle speed sensor 84.

The end point of the low speed range may be determined by the time t or the traveling distance D instead of the vehicle speed S. These figures 7, 8,
According to the algorithm shown in 9, the low speed range (L) when starting
Since only the low speed range (L) during deceleration is not detected,
As described above, unnecessary consumption of the battery can be reliably prevented.

In each of the above embodiments, as is clear from FIGS. 6 to 9, the auxiliary ratio η _M in the medium speed range (M) is substantially constant, but the present invention is not limited to this. In the present invention, the auxiliary ratio η _L in the low speed range is set to the auxiliary ratio η _M in the medium speed range.
The auxiliary ratio in the medium speed range and the high speed range may be set at any value.

[0030]

As described above, the invention according to claim 1 is a start-up method.
Al least stable at least subsidy rate during the start of the low <br/> speed range up to speed to become self-sustainable travel most significantly to
Subsequent medium speed assistance ratio is smoothly reduced from low speed assistance ratio
Since it is set to a substantially constant value that is lower than the subsidy rate in the low speed range, the subsidy rate in the medium speed range , which is used most often , is sufficiently small.
To reduce battery consumption and create a bicycle-like feeling.
On the other hand, when the vehicle is started , the wobble of the vehicle body is reduced and the starting operation becomes easier. For this reason also hill start easier, especially leg strength is so weak old man ride easily. in this case
In addition, the subsidy rate in the high-speed range is gradually reduced as the vehicle speed increases.
(Claim 2).

According to the invention of claim 3 , there is provided a bicycle with an electric motor which is directly used for carrying out the control method of claim 1. In this case, the subsidy rate is gradually reduced in the higher speed range.
Is preferable (Claim 4).

The starting determination means can have various configurations. For example, the low speed range is detected from the vehicle speed without distinguishing between starting and decelerating, and the assist rate during starting and decelerating is detected. Can be increased (Claim 5 ). The start determination means is a car
It is also possible to detect only the low speed range starting from high speed and make the assist rate during deceleration in the low speed range the same as the assist rate in the medium speed range (claim 6 ). In this way, when the start determination means detects the low speed range only when the vehicle is starting, the start may be detected from the vehicle speed, and then a constant time or a period up to a constant travel distance may be set as the low speed range at the start (claim 7, 8 ). Further, the start may be detected from the acceleration, and then the low speed range at the start may be set until a predetermined vehicle speed is reached (claim 9 ).

[Brief description of drawings]

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

FIG. 2 is a developed view of the II-II line in FIG.

FIG. 3 is a sectional view taken along line III-III in FIG.

[Fig. 4] Power system diagram

FIG. 5: Functional block diagram of controller

FIG. 6 is a characteristic diagram of the subsidy rate.

FIG. 7 is a diagram showing an example of a low-speed range detection algorithm when starting.

FIG. 8 is a diagram showing an example of a low speed range detection algorithm when starting.

FIG. 9 is a diagram showing an example of a low speed range detection algorithm when starting.

[Explanation of symbols]

34 crank pedal 36 electric motor 48 controller 64 Treading force sensor as treading force detection means 84 Vehicle speed sensor as vehicle speed detecting means 90 CPU 96 traveling control means 98 Start determination means

Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B62M 23/02

Claims (9)

(57) [Claims] 1. A method for controlling a bicycle with an electric motor in which a human power drive system and an electric drive system are provided in parallel, and the electric drive force is changed in response to a change in pedal power due to human power, the pedal force and vehicle speed are detected, At least stable and independent running from the start
The maximum ratio of the electric driving force to the human driving force at the start is maximized in the low speed range up to the speed at which the vehicle can move.
Comb, and the following subsidy ratio in the medium speed range from the subsidy ratio in the low speed range
Smoothly reduce it to a substantially constant value that is lower than the low-speed subsidy ratio.
Control method for a bicycle with an electric motor, characterized in that the to so that. 2. The high speed range auxiliary according to claim 1.
Rate electric motor that gradually decreases with increasing vehicle speed
To control an attached bicycle. 3. In a bicycle equipped with an electric motor, in which a human power drive system and an electric drive system are provided in parallel, and the electric drive force is changed in response to a change in pedal power due to human power, pedal force detection means for detecting pedal force and vehicle speed detection. Means and a little from the start of the bicycle
Starting determination means for detecting a low speed range up to a speed at which stable independent driving is possible, and electric drive for at least a human-powered driving force based on the output of the starting determination means in the low speed range The subsidy ratio of power is maximized and the following
Smoothly reduce the auxiliary ratio in the high speed range from the auxiliary ratio in the low speed range.
Electrically driven so that the value is lower than the auxiliary rate in the low speed range
A bicycle equipped with an electric motor, comprising: a traveling control unit that controls a system . 4. The traveling control means according to claim 3, further comprising:
In addition, the subsidy rate in the high speed range gradually decreases as the vehicle speed increases.
A bicycle with an electric motor that controls the electric drive system . 5. The start determination means detects a low speed range from the vehicle speed without distinguishing between starting and decelerating, and the traveling control means sets the assist rate during starting and decelerating to a level lower than that in the medium speed range. The bicycle with an electric motor according to claim 3 , wherein the electric drive system is controlled so as to have the same large auxiliary ratio. 6. start judgment means detects only the low speed range in starting the vehicle speed, the travel control means electric drive system so as to equal to the medium speed region of the auxiliary rate subsidy rate during deceleration in the low speed range
A bicycle with an electric motor according to claim 3 , wherein the bicycle is controlled . 7. The bicycle with an electric motor according to claim 3 , wherein the start determination means sets a low speed range from when the start operation is detected by the vehicle speed to when a predetermined time elapses. 8. The bicycle with an electric motor according to claim 3 , wherein the start determination means sets a low speed range from a time when the start operation is detected by the vehicle speed to a time when the vehicle travels a certain distance. 9. The bicycle with an electric motor according to claim 3 , wherein the start determination means sets the low speed range from when the start acceleration is detected when the start acceleration is equal to or higher than a certain value until the vehicle speed reaches a certain value. .