JP3327750B2 - Bicycle with electric motor and motor 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 drive system driven by a human power and a drive system driven by an electric motor in parallel, and controls the drive power of the electric motor in response to a change in the drive power (hereinafter referred to as "pedal force"). The present invention relates to a bicycle with an electric motor and a method for controlling the motor.

[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 in accordance with the magnitude of the driving force (Japanese Utility Model Application Laid-Open No. Sho 56-76590, Japanese Unexamined Patent Publication No. 2-74491).
issue). That is, when the human power increases, the driving force of the electric motor also increases, and the load of the human power is reduced. Here, a one-way clutch is interposed in the drive system of the motor to prevent the motor from turning when the motor is not energized or when the vehicle speed due to manual driving is higher than the rotation speed of the motor.

[0003] freewheel clutch sand driving force of human power (effort) provided on the wheel is inputted from the crank pedals
That is, since the power is transmitted to the rear wheel via the freewheel one-way clutch , the speed changes with a cycle of a half rotation of the crankshaft. This is because the pedaling force becomes almost zero when the crank pedal comes to the top dead center or the bottom dead center.

[0004] Figure 7 shows a change with respect to time t of the driving force or pedaling force F _L according to the human power. It changes the cycle of the pedaling force F _L corresponds to a half rotation of the crank pedals. Those previously proposed were those to increase or decrease the driving force of the motor by detecting the pedaling force F _L which periodically changes as this.

[0005]

In this case, [problems of the prior art, however, the motor is the pedal force F _L is approximately such that the speed in the composed time zero is substantially zero i.e. the driving force F _M also controlled to be substantially zero is, then pedal force F _L is as motor drive force F _M becomes positive to accelerate the motor by increasing the motor voltage V _M with to positive. Thus, the driving force F of the motor
_M will periodically fluctuate between a nearly zero state and the desired driving force.

[0006] Until it reaches the rotational speed N ₀ In this case the motor is the speed corresponding to the vehicle speed from a substantially zero state, the driving force F _M of the motor is out one-way clutch does not contribute to driving. Thus the driving force F _M of the motor for the time required to accelerate the meantime the motor (a in FIG. 7) is delayed in response to pedaling force F _L.

Further, the motor repeatedly accelerates from zero speed to a speed corresponding to the vehicle speed (N _{0 in} FIG. 7). During this period, it cannot contribute to the increase in the driving force at all. It will be wasted.

[0008]

THE INVENTION An object of the present invention has been made in view of such circumstances, the driving force F _M by the motor to improve the sense of operation by satisfactorily follow without delay the pedaling force F _L, also energy effective for It is a first object of the present invention to provide a motor control method for a bicycle with an electric motor capable of improving efficiency by use. It is a second object of the present invention to provide a bicycle with an electric motor that can be used directly for implementing the method.

[0009]

The first object according to the present invention DETAILED DESCRIPTION OF THE INVENTION, this wheel
A man-powered drive system that drives through a freewheel one-way clutch provided on the wheel and an electric drive system that drives the wheels by an electric motor are provided in parallel, and the electric drive system corresponds to a change in treading force due to manpower. A motor control method for a bicycle with an electric motor for controlling an output, wherein a one-way clutch is interposed in the electric drive system to increase or decrease the driving force of the motor in response to the increase or decrease in the pedaling force, while free-wheeling the human-powered drive system. The manual drive system upstream of the one-way clutch
The vehicle speed is detected from the rotation speed of the vehicle .
This is achieved by a motor control method for a bicycle with an electric motor, wherein the motor is driven at a corresponding no-load rotation speed, and the driving of the motor is stopped when the vehicle speed is substantially zero.

A second object is to provide, in parallel, a human-powered drive system for driving wheels via a freewheel one-way clutch provided on the wheels and an electric drive system for driving the wheels by an electric motor. A bicycle with an electric motor that controls the output of the electric drive system in response to a change in the treading force due to human power, a one-way clutch interposed in the electric drive system, a treading force detecting means for detecting a treading force, Vehicle speed detecting means for detecting the vehicle speed from the rotational speed of the human-powered drive system upstream of the freewheel one-way clutch of the system; and increasing or decreasing the driving force by a motor in response to the increase or decrease in the pedaling force. When the pedaling force is not substantially zero and the pedaling force is substantially zero, the controller drives the motor at a no-load rotation speed substantially corresponding to the vehicle speed at that time, and stops the driving of the motor when the vehicle speed is substantially zero. A bicycle with an electric motor, comprising: a roller;

The controller obtains a no-load motor voltage (V _M0 ) corresponding to the motor speed corresponding to the vehicle speed, and controls the driving force of the motor with respect to the pedaling force while maintaining the motor voltage at or above this voltage (V _M0 ). At the same time, when the vehicle speed becomes substantially zero, the driving of the motor can be stopped.

[0012]

[Principle] In a DC motor, the applied voltage (V
_M ), the motor current (I), and the rotation speed (N), the following equation holds. V _M = I · R + k · N where R is an amateur equivalent resistance, k is a proportionality constant,
k · N indicates the armature back electromotive voltage.

The motor torque (T _M ) depends on the type, but is generally almost proportional to the motor current (I). Therefore, the following equation is obtained using C as a constant. T _M = C · I Therefore, assuming that (R / C) = j, the following equation is obtained. V _M = j · T _M + k · N (1) In the equation (1), the first term (j · T _M ) on the right side is a term relating to torque, and the second term (k · N) is a rotation speed. It is a section about.

[0014] When the pedaling force F _L is 0 in the conventional apparatus to attempt to zero the motor rotational speed N and the driving force F _M of the motor to zero. That is, in equation (1), T _M
= 0 and N = 0. Thus the voltage applied to the motor V _M was also controlled to be zero.

[0015] In the present invention contrast, the motor rotation speed N even when the pedal force F _L is 0 when the vehicle speed is not substantially zero was set to maintain the idling speed N ₀ corresponding to the vehicle speed. That is, at the time of no load, the motor speed T _M = 0 and the rotation speed N = N ₀ . The no-load rotation speed N ₀ is a motor rotation speed required to generate the vehicle speed at this time, and substantially coincides with the rotation speed at which the one-way clutch of the electric drive system starts to be engaged or disengaged. Thus (1) = V _M from the equation _{j · 0 + k · N 0} = k · N 0

[0016] By maintaining the motor voltage V _M to the V _M0 is when this voltage V _M and no-load motor voltage V _M0, motor voltage V _M is below V _M0, even when the pedal force F _L is smaller motor rotation speed N is kept at the no-load rotational speed N _0. Thus since the motor may be generating a driving force F _M from N ₀ when the pedal force F _L becomes V _M ≧ V _M0 increases,
The time delay required for the acceleration of the motor is eliminated, and the energy (E _a ) consumed during the acceleration is not required.

In [0017] Note that a period of no-load motor voltage V _M0 to maintain the motor rotational speed N _0, the current I is the energy consumption E ₀ from extremely small much smaller than the energy E _a required for the acceleration. That is, since E ₀ ≪E _a , the efficiency is improved.

The vehicle speed S is a freewheel of a manual drive system.
Since the detection is performed at a rotation portion (e.g., a crank gear) upstream of the one-way clutch, if the rotation of the crank pedal is stopped during traveling, the detected vehicle speed gradually becomes zero. In the present invention, the driving of the motor is stopped at this time. That is, the voltage and current of the motor are cut off, the energy consumption of the battery is further reduced, and the efficiency is further improved.

[0019]

FIG. 1 is a side view of one embodiment of the present invention, and FIG.
3 is a power system diagram, FIG. 3 is a development view of the power system, FIG. 4 is a side view showing a treading force detecting section, FIG. 5 is a sectional view taken along the line VV, and FIG. 6 is a motor output characteristic diagram.

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

A lower portion of the seat tube 16 is formed with a tubular portion 16a opened downward, and a DC electric motor 22 is accommodated therein. A power unit 24 is fixed to a lower end of the seat tube 16. The power unit 24 includes a bottom bracket case (hereinafter referred to as a BB case) 26,
A rear stay 28 extends rearward from the BB case 26, and the rear wheel 14 is fixed to the rear end of the rear stay 28. The drive shaft 30 is inserted through the right rear stay 28 (FIG. 3).

Next, the power unit 24 will be described. Figure 1,
3, a crankshaft 32 is inserted into the BB case 26, and a crank 34 is fixed to both ends of the crankshaft 32. The crank 34 has crank pedals 36 attached thereto.

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 40 fixed to the right rear stay 28. A hub 42 is rotatably held on the axle 38, and the drive shaft 3
The rotation of 0 is transmitted via the bevel gear mechanism 44 and the freewheel one-way clutch 43.

The electric motor 22 is fitted and fixed to the BB case 26 from above as shown in FIG. 3, and its motor shaft 22a is orthogonal to the crankshaft 32 and located near the center in the vehicle width direction. The BB case 26 is a seat tube 1
The motor 22 is fitted into the cylindrical portion 16a so as to be inserted from below into the cylindrical portion 16a, and is connected by four bolts 46 (see FIG. 3).

As shown in FIG. 3, the rotation of the motor 22 is rotatably held on the crankshaft 32 via a one-way clutch 48, a planetary gear type reducer 50, a small bevel gear 52, and a large bevel gear 54. The resultant force is transmitted to a cylindrical resultant force shaft 56. The rotation of the resultant shaft 56 is further transmitted to the drive shaft 30 by a bevel gear mechanism 58.

The rotation from the rear wheel 14 to the motor 22 is interrupted by a freewheel one-way clutch 43 provided in the hub 42. Note that the planetary gear type speed reducer 50 is a known type, and the sun gear rotated by the motor 22 and the B gear
The revolving motion of the planetary gear which is located between and meshes with the ring gear fixed to the B case 26 is transmitted to the small bevel gear 52.

On the other hand, the rotation input manually from the pedal 36 is transmitted to the large bevel gear 54 via the crankshaft 32, the one-way clutch 60, and the planetary gear type gearbox 62. Therefore, the rotation input from the crankshaft 32 is transmitted from the large bevel gear 54 to the drive shaft 30 via the resultant shaft 56 and the bevel gear mechanism 58. The rotation of the crankshaft 32 is controlled by the action of the clutch 48 while the motor 22 is stopped.
Does not reach. During the stop or reverse rotation of the crankshaft 32, the rotation of the motor 22 is not transmitted to the crankshaft 32 by the action of the one-way clutch 60. Here the drive shaft 30
Is located on the right side of the plane A in the vehicle longitudinal direction including the motor shaft 22a (see FIG. 3).

As shown in FIGS. 3 and 5, the planetary gear type gearbox 62 includes a ring gear 62a fixed to a large bevel gear 54,
A sun gear 62b fixed to the pedaling force detection lever 64 and a planet gear 62c interposed therebetween are provided. The crankshaft 32 revolves the planetary gear 62c via the one-way clutch 60.

The pedaling force detecting lever 64 constitutes a part of a pedaling force detecting means 65 for detecting a driving force at the time of manual driving by the pedal 36 by a reaction force applied to the sun gear 62b. The treading force detecting means 65 is located on the left side of the plane A.

That is, the lever 6 of the treading force detecting means 65
4 are two projections 64a, 64b as shown in FIGS.
The one protrusion 64a abuts against the stopper 66 to restrict the clockwise rotation in FIG. 4, in other words, the rotation in the direction opposite to the direction in which the pedaling force of the pedal 36 is applied. Another second lever 68 abuts on the projection 64b, and the counterclockwise rotation of the lever 64 causes the second lever 68 to rotate clockwise.

The second lever 68 is provided with a return behavior by a return spring 70, whereby the lever 64 is moved to the position shown in FIG.
With this, return behavior in the clockwise direction is given. And this second
Of the lever 68 is transmitted to a potentiometer 72 as a pedaling force sensor. As a result, the lever 64 rotates counterclockwise in FIG.
Of the lever 68 rotates clockwise, the pedaling force is obtained from the rotation amount of the potentiometer 72.

In FIG. 1, reference numeral 80 denotes a rechargeable battery such as a lead battery, and reference numeral 82 denotes a controller, which is accommodated between the head pipe 12 and the seat tube 16 of the main frame 10. In FIG. 3, reference numeral 84 denotes a vehicle speed detecting means provided to face the large bevel gear.
Any known structure that detects the rotation electromagnetically or optically can be used.

The pedal force F _L detected by the potentiometer 72
And the vehicle speed S detected by the vehicle speed detecting means 84 are input to a controller 82, and the controller 82
_The motor current is controlled based on _L and the vehicle speed S to generate a motor torque T _M.

That is, the controller 82 calculates the motor rotation speed required for generating the vehicle speed S, that is, the no-load rotation speed N _0, and _{calculates the} no-load motor voltage V _M0 (= KN ₀ ) corresponding to the speed N _0. obtains the motor torque T _M corresponding to pedaling force F _L. It goes without saying that the data used for this calculation is stored in the memory 82a (FIG. 2) in advance.

Furthermore seek motor application voltage V _M based on the equation (1). In this equation (1), j> 0, T _M
Since ≧ 0, V _M ≧ V _M0 . That is, the motor voltage V _M
Does not _fall below V _M0 . When the detected vehicle speed S becomes 0, that is, when the driving of the manual drive system is stopped, the voltage and current of the motor are cut off and the driving is stopped.

Next, the operation at this time will be described with reference to FIG. The characteristic of the equation (1) is a straight line with a slope of − (k / j) falling to the right as shown by the solid line. Motor voltage V _M for outputting the torque T _M of the motor determined by a certain depression force F _L now
Is obtained from Expression (1) using the motor rotation speed N ₀ at that time, the operating point at that time is a point indicated by A in FIG.

[0037] Consider the case that here in the pedaling force F _L is reduced.
It is considered that the vehicle speed S during actual running does not change due to inertia, the crankshaft 32 rotates at a speed at which the one- way clutch 60 and the freewheel one-way clutch 43 do not disengage, and the vehicle speed detecting means 84 determines the actual vehicle speed at that time. It is assumed that it has been detected.

[0038] Since the vehicle speed detecting means 84 when the detects the actual vehicle speed S, the controller 82 is motor speed slide into reduced only V _M to leave N _0. That operating point A at this time the rate is lowered over the line AB of N _0. When it goes pedal force F _L is approximately _{0 V M = V M0 = kN} 0
Becomes, the controller 82 maintains the motor voltage V _M to V _M0. Accordingly, the operating point of the motor is maintained at the point B and the motor is operated without load.

[0039] When the depressing force F _L is V _M> V _M0 increases again, to move the operating point from point B toward the point A. At this time, since the motor has already been rotating at the speed N ₀ , there is no time delay until the one-way clutch 48 is engaged due to acceleration of the motor as in the prior art, and the delay a described in FIG. .

In the present invention, the vehicle speed detecting means 84 is provided to face the large bevel gear 54. That is, it is provided between the crankshaft 32 of the manual drive system and the freewheel one-way clutch 43. Therefore, if the rotation of the crankshaft 32 is stopped during a downhill or an inertia run, the large bevel gear 54 gradually decelerates and the speed N ₀ output by the vehicle speed detecting means 84 is output.
Becomes 0. Accordingly, at this time, the no-load motor voltage V _M0 is also set to 0 and the driving of the motor 22 is stopped even though the vehicle is actually running, so that the energy consumption can be further reduced.

In the present invention, F _M , V _M ,
T _M , N, N ₀ , data, and the like may be increased or decreased or changed within a range where the effects of the present invention can be obtained, and the present invention includes this case. For example, the no-load motor voltage V _M0 may be slightly higher or lower than kN ₀ obtained by equation (1). Further, the vehicle speed detecting means 84 may be provided on the upstream side of the freewheel one-way clutch 43 of the manual drive system, and may not detect the actual vehicle speed.

In the above embodiment, the rear wheel 14 is driven by a transmission system comprising a shaft drive mechanism using the drive shaft 30. In the present invention, a sprocket is fixed to the resultant shaft 56 and the transmission system comprises a chain drive mechanism. It may drive the rear wheels 14.

[0043]

As described above, according to the first aspect of the present invention, the vehicle speed is detected from the rotational speed on the upstream side of the freewheel one-way clutch of the manual drive system, and the detected vehicle speed is not substantially zero and the pedaling force (F _{When L} ) becomes substantially zero, the motor is driven at a no-load rotation speed substantially corresponding to the vehicle speed at that time. Therefore, even if the pedaling force (F _L ) periodically decreases, the motor continues to rotate with no load. Will be.

For this reason, the motor almost corresponds to the vehicle speed at that time.
It continues to be driven by the idling speed to, almost no acceleration or deceleration of the motor, the driving force of the motor (F _M) delay can be reduced relative to the pedal effort (F _L) of, thereby improving the sense of operation. In addition, since the acceleration and deceleration of the motor is almost eliminated, the consumption of energy is reduced and the efficiency is improved. Further, if the driving of the manual drive system is stopped and the vehicle enters the inertial running or the downhill running, the detected vehicle speed becomes substantially zero. At this time, since the driving of the motor is also stopped, the consumption of energy is further reduced, and the efficiency is further improved.

According to the second aspect of the present invention, there is provided a bicycle with an electric motor which is used directly for carrying out this method.

Further, the controller determines that the detected vehicle speed is substantially
When it is not zero, the no-load motor voltage (V _M0 ) which becomes the motor rotation speed corresponding to the actual vehicle speed is obtained, and the motor voltage (V _M ) is always kept higher than the no-load motor voltage (V _M0 ). In addition, the motor can be controlled so as to stop driving the motor when the detected vehicle speed is substantially zero (claim 3). In this case, the pedaling force becomes almost zero,
Conversely, there is no acceleration or deceleration of the motor when increasing from almost zero,
The effect of the present invention is further enhanced.

[Brief description of the drawings]

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

Fig. 2 Power system diagram

FIG. 3 is a development view of the power system.

FIG. 4 is a side view showing a treading force detection unit.

FIG. 5 is a sectional view taken along line VV.

FIG. 6 is an operating characteristic diagram of a motor.

FIG. 7 is a diagram showing periodic fluctuations of pedaling force and motor driving force.

[Explanation of symbols]

Reference Signs List 14 rear wheel 22 electric motor 30 drive shaft forming transmission system 32 crankshaft 36 crank pedal 43 freewheel one-way clutch 48 electric drive system one-way clutch 60 manual drive system one-way clutch 65 torque detecting means 82 controller 84 vehicle speed Detection means

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

Claims (3)

(57) [Claims] 1. A human-powered drive system for driving wheels via a freewheel one-way clutch provided on the wheels and an electric drive system for driving wheels by an electric motor are provided in parallel.
In a motor control method for a bicycle with an electric motor that controls an output of the electric drive system in response to a change in treading force due to human power, a one-way clutch is interposed in the electric drive system, and a motor is controlled in response to an increase or decrease in the treading force. While increasing or decreasing the driving force, the vehicle speed is detected from the rotational speed of the human-powered drive system upstream of the freewheel one-way clutch of the human-powered drive system, and when the vehicle speed is not substantially zero and the pedaling force is substantially zero, the motor is detected. Is driven at a no-load rotation speed substantially corresponding to the vehicle speed at that time, and the driving of the motor is stopped when the vehicle speed is substantially zero. 2. A human-powered drive system for driving wheels via a freewheel one-way clutch provided on the wheels and an electric drive system for driving the wheels by an electric motor are provided in parallel.
In a bicycle with an electric motor that controls an output of the electric drive system in response to a change in treading force due to human power, a one-way clutch interposed in the electric drive system, treading force detecting means for detecting treading force, and the human-powered drive system A freewheel one direction <br/> vehicle speed detecting means for detecting a vehicle speed from a rotational speed of the human-powered driving system on the upstream side of a clutch; and A controller that drives the motor at a no-load rotation speed corresponding to the vehicle speed at the time when the pedaling force is not substantially zero and the pedaling force is substantially zero, and stops driving the motor when the vehicle speed is substantially zero. A bicycle with an electric motor. 3. A human-powered drive system for driving wheels via a freewheel one-way clutch provided on the wheels and an electric drive system for driving wheels by an electric motor are provided in parallel.
In a bicycle with an electric motor that controls an output of the electric drive system in response to a change in treading force due to human power, a one-way clutch interposed in the electric drive system, treading force detecting means for detecting treading force, and the human-powered drive system vehicle speed detecting means for detecting a vehicle speed from the rotational speed of the manpower drive system on the upstream side of the free wheel direction <br/> clutch, when the vehicle speed is not substantially zero
The no-load motor voltage (V _M0 ) which becomes the motor rotation speed corresponding to the vehicle speed is obtained from this no-load motor voltage (V _M0 ).
An electric motor, characterized in that it comprises a controller for stopping the driving of the motor when the vehicle speed is substantially zero to control the in response to the depression force while maintaining the motor voltage (V _M) driving force by the motor above With bicycle.