JP2007191114A - Vehicle with power assist - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle having a power assist such as an electric bicycle capable of keeping a superior running stability even if the bicycle is re-accelerated after performing an inertia running and further without giving any discomfort to the bicycle rider. <P>SOLUTION: A vehicle with a power assist of this invention is characterized in that the vehicle comprises a torque sensor 4 acting as a manual driving force detecting means for use in detecting a manual driving power, an electric motor 1 acting as an assist driving force generating means for use in generating an assist driving force that is calculated by multiplying the manual driving force with an assist rate, an inertia running sensing means 7 for use in detecting an inertia running of the vehicle, and an assist rate control means 8 for setting the assist rate smaller than a predetermined assist rate when the inertia running is detected by the inertia running sensing means 7. This arrangement causes an added assist driving force to be reduced even if pedals are strongly treaded on by a driver, enables a superior running stability to be maintained and at the same time can prevent any discomfort from being given to the driver. <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 to assist in addition 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 is applied correspondingly, and the vehicle starts suddenly. The driver may feel uncomfortable. Further, when the driver applies a large pedaling force even though the vehicle is already traveling at a high speed, a large auxiliary driving force is applied, which may cause a very high speed.

  In order to deal with such problems, a speed detection means for detecting the traveling speed of the electric bicycle is provided, and a low (low) assist rate is set at the start, and the assist rate is gradually increased as the speed increases in the low speed range, For example, Patent Document 1 discloses a method in which when a predetermined speed is exceeded in a high speed range, the assist rate is gradually decreased as the speed exceeding the speed increases.

  Further, in Patent Document 2, a means for detecting a treading force as a human driving force and a means for detecting a running speed are provided to detect the start of an electric bicycle, and the vehicle such as the electric bicycle is always started. A method in which a constant small assist rate is set, and then the assist rate is gradually increased at a predetermined rate (for example, by 10%) over time, and finally returned to the reference assist rate after a predetermined time (so-called software) Start) is disclosed.

  Further, Patent Document 3 detects a pedaling force (pedal pedaling force) as a human driving force, and pauses the assist (auxiliary driving operation) until the pedaling force reaches a predetermined threshold from the traveling stop state (auxiliary driving force). When the pedaling force exceeds the threshold value and assist is started, the assist rate is increased from a small level assist rate (drive duty ratio) and calculated at a predetermined assist rate corresponding to the pedaling force. A method of gradually increasing from a value smaller than the force is disclosed.

  According to the methods disclosed in these patent documents 1 to 3, since the assist rate is adjusted to be small at the start by detecting the travel speed, the travel distance, the travel stop state, etc., the driver is Even when a large pedaling force is applied, the auxiliary driving force is suppressed to a small value, and it is possible to prevent a sudden start or a feeling of strangeness. Further, according to the method disclosed in Patent Document 1, even when the vehicle is already running at a high speed, the assist rate is adjusted to be small, so that it is possible to prevent the electric bicycle from becoming even faster.

  Patent Document 4 is provided with a means for detecting a treading force torque as a human power driving force and a travel distance calculating means for calculating a travel distance, respectively, and when the travel distance is small, the assist ratio is switched to a larger assist ratio. A method is disclosed.

According to the method of Patent Document 4, since the assist rate is adjusted to be large at the time of starting, there is a drawback that the vehicle starts suddenly at the time of starting.
Japanese Patent No. 2623419 Japanese Patent No. 3480998 Japanese Patent No. 3306309 JP 2002-264882 A

  However, according to the methods of Patent Documents 1 to 4 described above, a method of adjusting the assist rate at the time of starting, low speed, or high speed is adopted, and the assist rate is constant at other times. During driving, for example, while the vehicle is running with the pedal depressed, the pedal is temporarily depressed and the vehicle uses the inertia to perform so-called inertial driving. When the pedal is strongly depressed, the auxiliary driving force is suddenly applied, which may cause the driver to feel uncomfortable or decrease driving stability.

  The present invention solves the above-mentioned problem. Even when the vehicle is re-accelerated after inertial running, it can maintain good running stability and has an auxiliary power such as an electric bicycle that does not give the driver a sense of incongruity. The object is to provide a vehicle.

  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. Force generating means, inertia traveling detection means for detecting inertial traveling of the vehicle, and assist rate control means for setting an assist rate smaller than a preset assist rate when inertial traveling is detected by the inertial travel detecting unit. It is characterized by that.

  With this configuration, after inertial running, when the pedal is depressed, a large human power driving force is output, and when the auxiliary driving force is output, the assist rate is changed to a small assist rate. Even in this case, the auxiliary driving force to be applied becomes smaller, so that good running stability can be maintained and the driver can be prevented from feeling uncomfortable.

  The inertial running detection means may be a state in which it is determined that the vehicle is traveling inertial when the electric motor is stopped for a predetermined time or a state where no human driving force is substantially applied or crank Inertia travel can be detected by determining that the vehicle is traveling inertially when a predetermined time has elapsed with the shaft not rotating.

  As described above, according to the present invention, the inertial traveling detection unit detects the inertial traveling of the vehicle, and the assist rate control unit sets the assisting force to be small when the auxiliary driving force is output after the inertial traveling, thereby performing the inertial traveling. After that, even if you depress the pedal strongly, the added auxiliary driving force will be smaller, maintain good running stability, improve reliability, and prevent the driver from feeling uncomfortable, good Can maintain a comfortable ride.

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 electric power to the electric motor 1 and the like, and a torque as a human power driving force detecting means that is disposed at a position facing the crankshaft 19 and detects a human power driving force that is a stepping force by which the driver steps on the pedal 3. A sensor 4, a motor speed detector 5 for detecting the speed of the electric motor 1, a motor current detector 6 for detecting a current value of the electric motor 1, and an inertia for detecting that the electric bicycle is traveling inertially. The torque to be output from the electric motor 1 in accordance with information from the travel detection means 7, the assist rate control means 8 for adjusting the assist rate, the inertia travel detection means 7 and the assist rate control means 8. Motor output control means 9 for controlling the electric motor 1 so that an auxiliary driving force is output, a power operation switch 11 which is attached to the handle 12 of the electric bicycle and turns on / off the power supply, A brake operation detection sensor 15 for detecting that the brake is operated by operating the left and right brake levers 13 and 14 attached to the handle 12, a timer 20 for timing, and a storage unit for storing various setting information 21 etc. are provided. In this embodiment, the inertia traveling detection means 7, the assist rate control means 8, the motor output control means 9, the timer 20, the storage section 21 and the like are provided in the control section 10, but the present invention is not limited to this. It is not a thing.

  Here, the output gear of the electric motor 1 meshes with and interlocks with the chain 16 that transmits the rotation of the pedal 3 to the rear wheel via a reduction mechanism for transmitting auxiliary driving force. A one-way clutch mechanism is interposed in the speed reduction mechanism. When the electric motor 1 is not driven, a load from the electric motor 1 side on the chain 16 does not act, and the chain 16 moves. The electric motor 1 is configured not to rotate. Further, a one-way clutch mechanism is also interposed between the rear wheel sprocket 17 meshing with the rear portion of the chain 16 and the hub of the rear wheel 18, which is faster than the chain 16 when the electric bicycle is running inertially. When the hub of the rear wheel 13 rotates forward at the speed, the chain 16 does not move. Further, a one-way clutch mechanism is also interposed between a crank shaft (crankshaft) 19 to which the pedal 3 is attached and a crank sprocket attached to one side of the crankshaft 19 and meshed with the chain 16. Only when the pedal 3 is mounted and the pedal 3 is rotated (more precisely, when the peripheral speed on the forward side of the outer peripheral tooth portion meshing with the chain 16 of the crank sprocket is larger than the moving speed of the chain 11) The driving force from 3 is transmitted to the chain 16 side.

The inertia traveling detection means 7 detects whether or not the inertia traveling is based on the information of the motor rotation number detector 5 while referring to the timing information from the timer 20.
That is, as shown in FIG. 3, when the power operation switch 11 is switched to the ON state (step S1), the time during which the electric motor 1 is stopped and continued (referred to as motor stop time) is set to 0. The initial setting is that the vehicle is in the non-inertia running state (non-motor stopped state) (step S2). Then, it is determined whether or not the motor speed output from the motor speed detector 5 is 0 (step S3). If the motor speed is not 0, the process returns to step S2 to reset the motor stop time to 0. In addition, the non-inertia running state (non-motor stopped state) is set. On the other hand, when the motor rotational speed output from the motor rotational speed detector 5 is 0, that is, when the electric motor 1 is stopped and there is no output from the electric motor 1, the process proceeds to step S4, and the motor Add stop time. In step S5, it is determined whether the motor stop time has exceeded a preset time A. That is, if the motor is continuously stopped, the processes of steps S3 to S5 are repeated, and when the motor stop time exceeds the set time A, the process proceeds to step S6 and the inertial running state (motor stopped state). Judge that there is. On the other hand, if the electric motor 1 starts rotating before the motor stop time reaches the set time A, the process proceeds from step S5 to step S2 via step S3, and is in a non-inertia running state (non-motor stop state). judge. In the determination of whether or not the motor rotation speed is 0 in step S2 and the determination operation in step S13 described later, the electric motor 1 does not have to be strictly 0, even if the motor rotation speed is close to 0. The motor rotation number is 0 when the auxiliary drive force from the electric motor 1 is substantially equal to or less than the rotation number considered not to be output (the electric motor 1 rotates). May not be considered).

  The assist rate control means 8 performs the following control operation to determine the assist rate. Here, the assist rate is an auxiliary drive rate (integration coefficient) for calculating the auxiliary drive force by adding to the human drive force, and in this embodiment, a smaller first assist rate (for example, 70%). B1 and a larger second assist rate (for example, 150%) B2 are preset and stored.

  As shown in FIG. 4, when the power operation switch 11 is switched to the ON state (step S11), the assist rate is first set to a smaller first assist rate B1 (step S12). Then, it is determined whether or not the motor rotational speed output from the motor rotational speed detector 5 is greater than 0 (step S13). If the motor rotational speed is 0 (that is, if the vehicle has not started yet), step Returning to S12, the assist rate is maintained at the first assist rate B1 which is smaller.

  On the other hand, when the motor rotational speed is greater than 0, that is, when the electric motor 1 is rotating and output by the electric motor 1 (when starting is started), the process proceeds from step S13 to step S14. First, it is determined whether or not the assist rate is smaller than the second assist rate B2. At this time, since the assist rate is the first assist rate B1 that is smaller and smaller than the second assist rate B2 that is larger, the process proceeds to step S15, and the current assist rate is increased by a predetermined amount (for example, 0. 0). 1) Add assist rate only. Thereafter, the process proceeds to step S16, where the inertial running detection means 7 inputs determination information as to whether or not it is determined that the vehicle is in the inertial running state. If 1 is rotating, or if the electric motor 1 is stopped but the set time A has not been reached, the process returns to step S14. In a situation where the assist rate has not reached the larger second assist rate B2, in step S15, the assist rate is further increased by a predetermined increment (for example, 0.1), and the assist rate is increased. When the second assist rate B2 is reached, the assist rate is maintained without going through step S15. On the other hand, if it is determined in step S16 that the vehicle is in the inertial running state, the process returns to step S12, and the assist rate is reset to a smaller first assist rate B1.

Further, the motor output control means 9 performs the following control operation according to the information from the assist rate control means 8.
As shown in FIG. 5, when the power operation switch 11 is switched to the ON state (step S21), first, the electric motor 1 is stopped (step S22), the torque signal from the torque sensor 4 is detected, and the pedal is 3 is judged (whether the pedaling force on the pedal 3 has become larger than 0) (step S23), and when the pedaling force is not acting on the pedal 3, the process returns to step S22. Then, the electric motor 1 is stopped as it is. On the other hand, if it is detected by the torque sensor 4 that the pedal force is acting on the pedal 3, the process proceeds from step S23 to step S24, and the left and right brake levers 13, 14 are operated by the brake operation detection sensor 15. Determine whether it has been. When none of the brake levers 13 and 14 is operated, the assist rate set by the assist rate control means 8 is added to the detected pedaling force (manpower driving force (torque)), and the electric motor 1 Output torque (auxiliary driving force (torque)) is calculated, and the motor output torque is controlled to be output from the electric motor 1. Even when the pedaling force is detected, when it is detected that at least one of the brake levers 13 and 14 is operated, the process returns to step S22 and the electric motor 1 is stopped. That is, the motor output control means 9 controls the electric motor 1 so as to meet the calculated auxiliary driving force only when the pedal force is substantially applied to the pedal 3 and neither of the brake levers 13 and 14 is operated. In other cases, the electric motor 1 is stopped.

  The auxiliary driving force such as the pedaling force (torque), the rotation of the electric motor 1 and the motor current is detected at any time, and the detection time interval is 10 ms, for example, and a moving average value of a plurality of continuous detection values may be used. This is not a limitation. Since the load due to the auxiliary driving force output from the electric motor 1 is substantially proportional to the motor current, the motor output control means 9 controls the auxiliary driving force corresponding to the motor current to be output.

  According to the above configuration, at the time of starting, the assist rate is automatically set to the smaller first assist rate B1, as shown in a simplified manner at the left side in FIG. Even when is added, the auxiliary driving force is suppressed to be small, and it is possible to prevent sudden start or giving a sense of incongruity. Note that the dotted line portion on the left side in FIG. 6 (a) indicates the pedal when the same pedaling force is applied three times at the start (more specifically, for example, the pedal is depressed three times such as the right foot, left foot, and right foot). In this case, as shown in FIG. 6B, the assist rate is gradually increased (abruptly increased) from the first assist rate B1, and the auxiliary driving force is also gradually increased accordingly. Assisted well.

  FIG. 6A is a diagram showing the relationship between the pedal depression force (manual driving force: dotted line portion) and the motor output (auxiliary driving force: solid line portion) of the electric bicycle when starting and running. FIG. ) Is a diagram showing a change state of the assist rate at that time, FIG. 6C shows the vehicle speed, and FIG. 6D shows the rotation state (the number of rotations) of the electric motor 1.

  In particular, in the present invention, as schematically shown in the central portion in FIG. 6, the driver's stepping is interrupted after the start and the driver does not step for a while, and the electric motor 1 rotates. If the set time A is exceeded in a state where the inertial travel is not performed, it is determined by the inertial travel detection means 7 that inertial travel has been performed. Accordingly, as shown in FIG. The assist rate B1 is changed. As a result, even if the driver applies a large pedaling force after inertial driving to re-accelerate, the auxiliary driving force is kept small, maintaining good driving stability and improving reliability, It can prevent a sense of incongruity and maintain a good ride comfort.

  In addition, as shown in the right side in FIG. 6, after the driver's stepping is interrupted after starting, if the stepping is started without much time (within the set time A), Since the state in which the motor 1 does not rotate is within the set time A, it is determined that the inertial traveling detection means 7 is non-inertial traveling, and the assist rate is decreased by the assist rate control unit 8 as shown in FIG. Is not done. As a result, even when there is an instantaneous stop state of the electric motor 1, the assist rate before this is continued and good assist is provided.

  In the above embodiment, the case where the motor speed detector 5 detects whether the electric motor 1 is rotating is described. In this case, there is an advantage that the motor speed can be accurately detected. The present invention is not limited to this, and an inexpensive detection means that can simply detect whether the electric motor 1 is rotating or stopped may be substituted. Instead of detecting whether or not the electric motor 1 is actually rotating, the rotation and stop of the electric motor 1 may be determined based on the content of the motor output instruction signal in the motor output control means 9.

  Further, in the above embodiment, as shown in FIG. 6D, when the electric motor 1 is stopped for a predetermined time by the inertia traveling detection means 7, it is determined that the vehicle is traveling inertia. However, instead of this, when the brake operation detection sensor 15 detects that any one of the brake levers 13 and 14 is operated, the electric motor 1 has been stopped for a predetermined time, or When there is no motor output instruction from the motor output control means 9, it may be determined that the vehicle is inertial running and the same motor output control may be performed. In addition, FIG.6 (e) shows a brake operation timing simply.

  In addition, when the electric motor 1 has stopped for a predetermined time, instead of determining that the vehicle is traveling inertially, a torque sensor indicates that a pedal depression force that is a human driving force is not substantially applied. 4, when this state has passed for a predetermined time, the inertial traveling detection means 7 determines that the vehicle is traveling inertially, or means for detecting the rotation of the crankshaft 19 is provided. It may be determined that the vehicle is traveling inertial when a predetermined time has elapsed with the shaft 19 not rotating.

  Furthermore, in the above-described embodiment, the electric bicycle is changed to the first assist rate B1 that is the smallest after inertial running, and is also changed to the first assist rate B1 when stopped after starting. The present invention is not limited to this, and means for detecting whether the electric bicycle is running or stopped, for example, a vehicle speed detection sensor (for example, a sensor for detecting the rotation amount of the rear wheel or the front wheel) is provided, When the motor 1 has stopped for a predetermined time, it may be determined that the vehicle is traveling inertial. In this case, the inertial traveling of the vehicle can be detected more accurately. Further, in this case, instead of changing to the smallest first assist rate B1, the assist rate is decreased by the current predetermined amount of assist rate (for example, 30%) (for example, the current assist rate is When it is 100% or less, the first assist rate B1 (for example, 70%) is uniformly set, and the third assist rate B3 is intermediate between the first assist rate B1 and the second assist rate B2. You may decrease it. In this case, since the vehicle is already running, even if the assist rate to be decreased is small, it is possible to assist the vehicle well without losing the running stability or feeling uncomfortable as the vehicle starts.

  Needless to say, the specific value of the assist rate is not limited to the above embodiment. In the above-described embodiment, the case where the assist rate is significantly changed once has been described when the condition is met. However, the present invention is not limited to this. The assist rate may be lowered by dividing it into multiple times.

  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.

  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 Flowchart showing the control operation of the inertia traveling detection means of the electric bicycle The flowchart which shows the control operation of the assist rate control means of the same electric bicycle Flow chart showing control operation of motor output control means of the electric bicycle (A) is a diagram showing the relationship between the pedal depression force (human power driving force: dotted line portion) and motor output (auxiliary driving force: solid line portion) of the electric bicycle when starting and running the electric bicycle; The figure which shows the change state of the assist rate in that case, (c) is a figure which shows vehicle speed, (d) is a figure which shows the rotation state (rotation speed) of the electric motor 1, (e) is a figure which shows brake operation timing.

Explanation of symbols

1 Electric motor (Auxiliary driving force generating means)
2 Battery 19 Crankshaft 3 Pedal 4 Torque sensor (manual driving force detection means)
DESCRIPTION OF SYMBOLS 5 Motor rotation speed detector 6 Motor current detector 7 Inertia travel detection means 8 Assist rate control means 9 Motor output control means 10 Control part 11 Power supply operation switch 13, 14 Brake lever 15 Brake operation detection sensor 16 Chain 20 Timer 21 Storage part

Claims (4)

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;
Inertia traveling detection means for detecting inertia traveling of the vehicle;
A vehicle with auxiliary power, comprising: assist rate control means for setting an assist rate smaller than a preset assist rate when inertial running is detected by the inertial running detection means.   The vehicle with auxiliary power according to claim 1, wherein the inertia traveling detection means determines that the vehicle is traveling inertia when the electric motor is stopped for a predetermined time.   The inertial traveling detection means determines that the vehicle is traveling inertially when a predetermined time has elapsed in a state where no human driving force is substantially applied or in a state where the crankshaft is not rotating. Vehicle with auxiliary power.   The vehicle with auxiliary power according to any one of claims 1 to 3, wherein the vehicle with auxiliary power is an electric bicycle.

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