JP2007161219A - Vehicle with auxiliary power - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle with auxiliary power such as an electric bicycle capable of applying suitable auxiliary drive force in response to an inclination angle or the like of a traveling position in starting while suppressing increase of manufacturing cost to the minimum. <P>SOLUTION: Starting of the vehicle is detected by a starting detection means 6 and when a speed of the vehicle is not more than a lower limit determination speed while the sum of human power drive force and the auxiliary drive force is larger than an increase determination drive force value, it is changed to a larger assist ratio than a previously set reference assist ratio. When the speed of the vehicle is larger than an upper determination speed while the sum of the human power driver force and the auxiliary drive force is still smaller than a reduction determination drive force value, it is changed to a smaller assist ratio than the reference assist ratio. Rapid staring is prevented in starting and the starting is well performed even on an upslope. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vehicle with auxiliary power such as an electric bicycle.

  An electric bicycle that can easily travel even on an uphill has already been put into practical use by adding the auxiliary driving force of a motor unit equipped with an electric motor to the driving force by human power. In this type of electric bicycle, the pedaling force is generally detected by a torque sensor or the like as a driving force by human power, and a value obtained by integrating a certain assist rate (referred to as a reference assist rate) is calculated as an auxiliary driving force. The auxiliary driving force is generated from the electric motor and applied to the human driving force.

  However, if the assist rate is always constant, for example, when the driver applies a large pedaling force when starting on a flat road or downhill, a large auxiliary driving force corresponding to this is applied, and there is a risk that the vehicle will start suddenly. is there.

  In order to prevent such inconvenience, Patent Document 1 discloses that a constant assist rate is always set to a low value when starting a vehicle such as an electric bicycle, and thereafter, gradually, a predetermined ratio (for example, A method (so-called soft start) is disclosed in which the assist rate is increased by 10%) and returned to the final reference assist rate after a predetermined time. According to this method, even when a large pedaling force is applied when starting on a flat road or a downhill, it is possible to prevent the vehicle from starting suddenly.

  However, according to this soft start method, a low assist rate is always obtained at the time of starting, and only a small auxiliary driving force is applied, so there is a high possibility that starting on an uphill cannot be performed satisfactorily.

In order to deal with this, in addition to the above soft start method, it is conceivable to provide an electric bicycle with an angle sensor for measuring the tilt angle of the vehicle and to increase the assist rate as the tilt angle increases. . In the angle sensor, for example, a weight (contact) for detecting an angle is disposed in a predetermined space (for example, a spherical cell space in which a plurality of electrode contacts are disposed on the outer periphery), and is in contact with the weight. The inclination angle is detected based on the position of the electrode contact.
Japanese Patent No. 3480998

  However, as described above, when an angle sensor is provided in the electric bicycle and the assist rate is increased as the tilt angle is larger, the angle sensor must be provided separately. Increase, and there is a risk of erroneous determination by the angle sensor. In such a case, an inappropriate assist rate may be set. In other words, when the vehicle suddenly starts uphill, the weight sensor tries to stay at its original position due to inertia, and the angle sensor erroneously determines that the inclination angle is larger than the actual angle, resulting in an actual inclination state. When the assist rate is larger than the appropriate assist rate, excessive auxiliary driving force is generated, or when the start is suddenly stopped, the weight tries to move due to inertia, and the reaction causes the tilt angle sensor to move beyond the actual angle. May be erroneously determined to be a small inclination angle, and the assist rate may be smaller than the assist rate suitable for the actual inclination state, and the auxiliary driving force may be insufficient.

  SUMMARY OF THE INVENTION The present invention solves the above-described problems, and can suppress an increase in manufacturing cost to a minimum and can apply an appropriate auxiliary driving force in response to an inclination angle of a traveling location when starting. It aims at providing vehicles with auxiliary power, such as.

  In order to solve the above problems, a vehicle with auxiliary power according to the present invention includes a human power driving force detecting means for detecting a driving force by human power, and an auxiliary driving for generating an auxiliary driving force calculated by integrating the human power driving force with an assist rate. A force generating means; a speed detecting means for detecting a traveling speed of the vehicle; a start detecting means for detecting the start of the vehicle; and a driving force for determining whether the sum of the human driving force and the auxiliary driving force is increased when the vehicle starts. If the vehicle speed is lower than the lower limit judgment speed even though it is larger than the value, the assist ratio is changed to a larger assist ratio than the preset reference assist ratio, and the sum of human driving force and auxiliary driving force is still reduced. Assist rate control means for changing the assist rate to a smaller assist rate than the reference assist rate when the vehicle speed is greater than the upper limit determination speed despite being smaller than the determination driving force value. .

  With this configuration, in the process of applying a relatively large pedaling force when starting on a flat road or downhill, the speed of the vehicle even though the sum of the human driving force and the auxiliary driving force is still smaller than the reduction determination driving force value. Is larger than the upper limit determination speed, the assist rate control means changes the assist rate to a lower assist rate than the reference assist rate. Therefore, even when a large pedaling force is applied on a flat road or a downhill, the assist rate is changed to a small assist rate in advance and the added auxiliary driving force becomes smaller, so that sudden start can be prevented.

  In addition, a relatively large pedaling force is applied when starting on an uphill, and the speed of the vehicle is smaller than the lower limit determination speed even though the sum of the human driving force and the auxiliary driving force is larger than the increase determination driving force value. In this case, the assist rate control means changes the assist rate to a larger assist rate than the reference assist rate, and the added assist driving force increases, so that it is possible to start well even on an uphill with a large slope.

  As described above, according to the present invention, it is possible to prevent a sudden start on a flat road or a downhill without providing an inclination angle sensor, and it is possible to start well on an uphill. In addition, since it is not necessary to provide a separate angle sensor, the manufacturing cost can be reduced correspondingly, and the occurrence of a malfunction due to erroneous determination of the tilt angle due to the use of the angle sensor can be prevented. And good reliability can be maintained.

Embodiments of the present invention will be described below with reference to the drawings.
As shown in FIGS. 1 and 2, an electric bicycle as an embodiment of a vehicle with an auxiliary drive device of the present invention includes an electric motor 1 as auxiliary drive force generating means for generating an auxiliary drive force to be added to a human power drive force. And a battery 2 for supplying electricity to the electric motor 1 and the like, a speed detecting means 3 for detecting the traveling speed of the electric bicycle, and a pedaling force for the driver to depress the pedal 9 The motor current is detected because the load due to the auxiliary driving force output from the electric motor 1 and the torque sensor 4 as a human driving force detecting means for detecting a certain human driving force is substantially proportional to the motor current, and the measurement result Auxiliary driving force detecting means 5 for calculating the auxiliary driving force from the above, a start detecting means 6 for detecting the start of the electric bicycle, and the sum of the human power driving force and the auxiliary driving force at the time of starting (hereinafter referred to as the sum) If the speed of the electric bicycle is smaller than the lower limit determination speed even though the drive force is greater than the increase determination drive force value, the assist ratio is changed to a higher assist ratio than the preset reference assist ratio. An assist rate control means for changing the assist rate to a lower assist rate than the reference assist rate when the speed of the electric bicycle is greater than the upper limit determination speed even though the drive force is still smaller than the decrease determination drive force value; A power supply operation switch 8 that is attached to a handle of an electric bicycle or the like to turn on / off power supply and a storage unit (not shown) are provided. In this embodiment, the auxiliary driving force detection means 5, the start detection means 6, the assist rate control means 7 and the like are provided in the control unit 10, but the present invention is not limited to this.

  Here, the output gear of the electric motor 1 meshes with and interlocks with the chain 11 that transmits the rotation of the pedal 9 to the rear wheel via the auxiliary driving force transmission gear. The rotational displacement amount of the electric motor 1 is measured by a rotational position sensor that measures the rotational displacement amount of the electric motor 1, and the speed data of the electric bicycle is calculated based on the measured rotational displacement amount data. However, the present invention is not limited to this, and a speed sensor provided separately is used to measure the speed of the electric bicycle, i.e., the vehicle speed, or a sensor that detects the amount of rotation of the rear wheels and the front wheels is provided to calculate the speed. There may be.

  The start detection means 6 is estimated that the pedaling force is substantially applied to the pedal, such as a pedaling force of a predetermined value (for example, 2 kg) from the state where the vehicle speed is 0 in a state where the power operation switch 8 is switched to the ON state. Value) or more, it is determined that the driver intends to start the electric bicycle, and the control unit 10 recognizes that the vehicle is in the start start state.

The assist rate is an auxiliary drive rate (integration coefficient) for calculating the auxiliary drive force by adding to the human drive force, and a reference assist rate (for example, 100%) is set in advance.
When the vehicle starts, for example, the assist rate control means 7 determines that the total driving force is larger than the increase determination driving force value within a predetermined time (for example, 10 seconds) after it is determined that the vehicle starts. Regardless, if the vehicle speed is lower than the lower limit determination speed (for example, a speed at which the vehicle speed is substantially higher than 0 (ie, the vehicle has actually started) such as 1 km per hour), the reference assist rate To a larger assist rate (for example, 150% or 200%). In addition, although the total driving force is still smaller than the reduction determination driving force value, the vehicle speed is the upper limit determination speed (for example, 5 km / h, or the vehicle speed is substantially higher than 0 (actually start If it is higher than the speed at which it can be recognized), the assist rate is changed to a lower assist rate (for example, 50%) than the reference assist rate.

  Note that the pedaling force, the vehicle speed, and the auxiliary driving force are detected at any time, and the detection time interval may be 10 ms, for example, and a moving average value of a plurality of consecutive detection values may be used, but is not limited thereto.

  In the above configuration, when the driver gets on the electric bicycle and turns on the power operation switch 8, as shown in FIG. 3, first, the driver is initially set to a preset reference assist rate (step S1). Then, it is determined whether or not a pedaling force is applied to the pedal 9 (a substantial pedaling force on the pedal is greater than 0) (step S2). If the pedaling force is greater than 0, the driver applies the pedaling force. It is determined that the vehicle is about to start after being applied, and the time point at which the detection of the pedaling force is started is recognized as the start time (step S3).

  When the start of start is recognized, it is first determined whether or not the total driving force is smaller than the decrease determination driving force value (step S4). When the total driving force is smaller than the decrease determination driving force value, the process proceeds to step S5, where it is determined whether the vehicle speed is larger than the upper limit determination speed. When the vehicle speed is higher than the upper limit determination speed, the assist rate control means 7 changes the assist rate to a lower assist rate than the reference assist rate (step S6). Accordingly, as briefly shown in FIGS. 4A and 4B, even when a large pedaling force T1 is applied at the time of starting on a flat road or a downhill, a small assist rate is obtained before the pedaling force T1 becomes maximum. Thus, the auxiliary driving force T2 added to the human driving force (stepping force T1) is suppressed to be small. As a result, the total driving force T3 is also suppressed to a small value, so that the electric bicycle is prevented from suddenly starting and safety is improved. 4A is a total driving force when the assist rate is not changed as a comparative example, V1 is a vehicle speed in FIG. 4B, and V2 is a comparative example when the assist rate is not changed. The vehicle speed.

  As a comparative example, FIG. 5 (a) simply shows the relationship between the driving force and time when the assist rate is not changed during normal start on a flat road, and FIG. 5 (b) The relationship between vehicle speed and time is shown. In FIGS. 5A and 5B, T1 is a pedaling force (manual driving force), T2 is an auxiliary driving force, T3 is a total driving force, and V1 is a vehicle speed.

  Even if it is determined in step S4 that the total driving force is smaller than the reduction determination driving force value, if it is determined in step S5 that the vehicle speed is equal to or lower than the upper limit determination speed, the assist rate is the reference. The assist rate is maintained.

  If it is determined in step S4 that the total driving force is greater than the decrease determination driving force value, the process proceeds to step S7, where it is determined whether or not the total driving force is greater than the increase determination driving force value. Is done. When the total driving force is larger than the increase determination driving force value, the process proceeds to step S8, and it is determined whether or not the vehicle speed is equal to or lower than the lower limit determination speed. When the vehicle speed is equal to or lower than the lower limit determination speed, the assist rate control means 7 changes the assist rate to a larger assist rate than the reference assist rate in step S9. Therefore, when the vehicle speed does not increase (below the lower limit judgment speed) even though the pedal is depressed with a relatively strong force, as in the case of starting from an uphill with a large slope, 6 (a) and 6 (b), since the assist rate is changed to a large assist rate and a large auxiliary driving force is added to the human power driving force, the vehicle can start well even on an uphill. In FIG. 6A, T1 is a pedaling force, T2 is an auxiliary driving force, T3 is a total driving force, T4 is a total driving force when the assist rate is not changed, and V1 in FIG. 6B is a comparative example. Vehicle speed and V2 are vehicle speeds when the assist rate is not changed as a comparative example.

Note that the control for adjusting the assist rate is performed until a predetermined time has elapsed from the start of the start, that is, at the start.
Thus, at the time of starting from the start of starting until a predetermined time elapses, as described above, the assist rate is changed to be suitable for the starting state, so that the vehicle can start well and the safety is improved.

  In addition, when the electric bicycle is equipped with a transmission (for example, a three-speed shift), it can start well without sudden start depending on the connection state of the shift speed regardless of the shift speed at the start. There are advantages. That is, for example, even in the case of the first speed (so-called high reduction ratio of Low), it is automatically adjusted to a small assist rate depending on the case, and sudden start is prevented.

  In addition, according to the present invention, it is not necessary to provide a separate angle sensor, so that the manufacturing cost can be reduced by that amount, and the malfunction due to the erroneous determination of the tilt angle due to the use of the angle sensor. Can also be prevented, further improving reliability.

  Needless to say, the vehicle speed, the treading force (human power driving force value), and the assist rate are not limited to the above embodiment. In the above-described embodiment, the case where the assist rate is significantly changed at one time has been described when the condition is met. However, the present invention is not limited to this, and gradually ( The assist rate may be lowered or raised in several steps. Further, in the above embodiment, a case has been described in which the start time is defined as a predetermined time from the start of start. However, the present invention is not limited to this, and even if a predetermined time elapses from the start of start, a predetermined time has passed. If the vehicle speed is not reached, the assist rate may be gradually increased considering that the vehicle is starting.

  Further, in the above-described embodiment, the case of an electric bicycle as a vehicle with an auxiliary drive device has been described. However, the present invention is not limited to this, and can be applied to an electric wheelchair or an electric motorcycle. Even in this case, it is possible to start well and safely.

  Also, in the above, the case where the running resistance is large due to the electric bicycle trying to climb uphill has been described. However, when the electric bicycle starts to blow strongly, the running resistance of the electric bicycle increases. Is also available.

  The vehicle with an auxiliary power device of the present invention can be used for an electric bicycle, an electric motorcycle, an electric wheelchair, and the like.

Schematic block diagram of a motor output control system of an electric bicycle according to an embodiment of the present invention Side view of the electric bicycle Flow chart showing control operation of the electric bicycle (A) And (b) is the figure which shows the relationship between each driving force and time in the case of starting with a strong stepping force on a flat road or downhill of the electric bicycle, and the vehicle speed and time. Diagram showing relationship (A) And (b) is a figure which shows the relationship between each driving force and time in the case of starting by adding a normal treading force on the flat road of the same electric bicycle, and a diagram showing the relationship between vehicle speed and time (A) And (b) is a figure which shows the relationship between each driving force and time in the case of starting by adding pedal force on the uphill of the same electric bicycle, and a figure which shows the relationship between vehicle speed and time

Explanation of symbols

1 Electric motor (Auxiliary driving force generating means)
2 Battery 3 Speed detection means 4 Torque sensor (human driving force detection means)
5 Auxiliary driving force detection means 6 Start detection means 7 Assist rate control means 9 Pedal 10 Control unit

Claims (2)

Human power driving force detecting means for detecting driving force by human power;
Auxiliary driving force generating means for generating auxiliary driving force calculated by adding the assist rate to the human driving force;
Speed detecting means for detecting the traveling speed of the vehicle;
Start detection means for detecting the start of the vehicle;
When the vehicle starts, if the vehicle speed is equal to or lower than the lower limit determination speed even though the sum of the human driving force and the auxiliary driving force is greater than the increase determination driving force value, If the vehicle speed is higher than the upper limit determination speed even though the sum of the human driving force and auxiliary driving force is still smaller than the decrease determination driving force value, the reference assist rate A vehicle with auxiliary power provided with assist rate control means for changing to a smaller assist rate. The vehicle with auxiliary power according to claim 1, wherein the vehicle with auxiliary power is an electric bicycle.

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