JPH0750802Y2 - Braking control device for electric vehicle - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a braking control device for an electric vehicle, and more particularly to controlling the deceleration characteristic of a motor in dynamic braking by a brake signal such as a manual brake so that the dynamic braking can be effectively operated. The present invention relates to a braking control device for an electric vehicle.

[0002]

2. Description of the Related Art A towing vehicle for towing an electric vehicle, particularly a dolly
In the case of, it is necessary to provide slow start and slow stop functions in order to prevent the load of the towed truck from falling or falling. On the other hand, it is possible to realize such a driving state by slowly opening and closing the speed control throttle by an artificial operation, but as a practical matter, there is also a relation such as the skill level of the driver. Yes, it is difficult to always perform a constant operation. FIG. 3 shows the operation state of the throttle. FIG. 3 (a) shows a temporal change of the accelerator voltage indicating the amount of operation of the stottle when abrupt opening / closing is performed, and FIG. 3 (b) shows a gradual change. The time change of the accelerator voltage when the switch is opened and closed is shown. In the case of manual operation, it is not always possible to perform gentle control as shown in FIG. 3 (b), so an integration circuit or the like should be provided in the control device.
Even when a sudden operation as shown in FIG.
It has been proposed to perform control by gradually changing the characteristics as shown in (b) (see, for example, Japanese Utility Model Application Laid-Open No. 59-119704), which enables even unskilled persons to perform smooth control. You will be able to start and stop, and you will not have to concentrate on the operation.

[0003]

However, in the method of grading the operation characteristics by using the integrating circuit or the like as described above, for example, when a sudden stop is required, the operation signal is not output even if the throttle is rapidly closed. Since it remains, the driving force of the motor does not decrease sharply. Therefore, it is necessary to use a mechanical brake that is provided separately to brake the vehicle body and at the same time to brake the motor itself that is generating the driving force. There was a problem that the braking distance could not be extended.

[0004]

SUMMARY OF THE INVENTION The present invention has improved the disadvantages of the prior art, and in particular, enables effective switching to the braking mode even when the accelerator is being operated without applying a load to the motor and mechanical brake involved in the accelerator operation. An object of the present invention is to provide a braking control device for an electric vehicle that can set a sudden braking state.

[0005]

SUMMARY OF THE INVENTION In the present invention, an accelerator voltage output circuit section 20 for generating a predetermined accelerator voltage according to a throttle operation amount and an accelerator voltage output from the accelerator voltage output circuit section 20 are provided. A motor drive control unit 21 that causes the motor to generate a driving force or causes the motor to perform dynamic braking in accordance with the magnitude, and a rapid accelerator voltage provided between the motor drive control unit 21 and the accelerator voltage output circuit unit 20. Brake switch 9 is provided with an accelerator signal integrating circuit 22 for converting such a change into a slow change and outputting it, and a brake switch 9 which is activated by the operation of a mechanical brake operator provided near the throttle. Is connected in parallel to the capacitor portion of the accelerator signal integrating circuit 22, so that the motor drive control unit 21 can operate the brake switch 9. Flip has a function to set the motor to the power generation braking state, as the brake switch 9 is operated in preference to the braking operation of Mechanica Le blanking <br/> rake In the operation sequence of the operating element for the mechanical brake The structure is such that it is connected to the mechanical brake operator. This aims to achieve the above-mentioned object.

[0006]

In the present invention, the resistance grounding circuit 10 is grounded by the brake switch 9 which operates in conjunction with the mechanical brake when it operates, and the integrating circuit 2 provided for grading the change in the accelerator voltage by this is grounded. The time constant of is sharply reduced and given priority over the mechanical brake. In this case, the brake switch 9 functions to perform dynamic braking before the mechanical brake operates. For this reason,
Even in an electric vehicle equipped with a soft stop function, sudden braking by dynamic braking can be effectively performed without imposing an excessive load on the engine.

[0007]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described below with reference to FIG. In FIG. 1, reference numeral 1 denotes a throttle volume which is a main part of the accelerator circuit section 20 and which is interlocked with the throttle. Further, reference numeral 22 is an integrating circuit for an accelerator signal including a resistor R and a capacitor C, reference numeral 3 is a comparator, reference numeral 4 is a sawtooth wave generator, reference numeral 5 is an exclusive OR circuit, reference numeral 6 is a changeover switch, reference numeral 7 Is an inverter, reference numeral 8 is a motor, reference numeral 9 is a brake switch that operates in conjunction with a mechanical brake, and reference numeral 10 is a resistance (r) as a resistance ground circuit. Reference numeral 21 indicates a motor drive controller. The motor drive control unit 21 has a function of causing the motor to generate a driving force or causing the motor to perform dynamic braking according to the magnitude of the accelerator voltage output from the accelerator voltage output circuit unit 20. Also,
FIG. 2 shows signals of respective parts in the embodiment of FIG. 1 to explain the operation of the present invention. In FIG. 1, a throttle volume 1 is connected to a throttle (not shown) and generates an accelerator voltage V _acc indicating a throttle operation amount based on the operation of the throttle. This accelerator voltage V _acc is an integrating circuit 2 including a resistor R and a capacitor C.
Even if there is a rapid change in the accelerator voltage V _acc at time t ₁ as shown in the waveform (a) of FIG. 2 due to the operation of the throttle due to the action of 2, the gradual change as shown in the waveform (b) of FIG. signal indicating the voltage V ^_acc, it is converted to. The comparator 3 compares the signal voltage V _acc ^, with the saw-tooth wave signal of the saw-tooth wave generator 4, and the output side thereof is pulled up to a constant voltage V _acc , so that the signal V _acc ^, When the voltage exceeds the voltage, a high-level output is generated, and thereby a switching signal V _s having a pulse waveform (chopping waveform) whose pulse width changes intermittently at a constant cycle is generated. On the other hand, signal V
^_acc, but when exceeding the peak value of the sawtooth wave, the switching signal V _s becomes the high level continuous signal, and the signal V _acc ^when, but equal to or less than the bottom value of the sawtooth wave, the switching signal V _s Is a low level continuous signal.

This switching signal V _s is used for controlling the driving force of the motor as described later, and the signal V _s is used.
When is a high-level continuous signal, the motor rotates at full power,
When the signal V _s is a low level continuous signal, the motor is in the dynamic braking state. Further, when the signal V _s is an intermittent pulse, the motor generates a driving force according to the pulse width. Here, such a drive signal generating method in the open loop control is conventionally known, and is disclosed by the applicant of the present invention in Japanese Patent Application Laid-Open No. 60-91803.
It is also described in the official gazette. The exclusive OR circuit 5 is supplied with a signal that goes to a low level when moving forward and goes to a high level when moving backward through the changeover switch 6.

Considering the case of forward movement, the switching signal V _s is given to the transistor TR1 via the exclusive OR circuit 5 without changing the polarity, and is inverted in polarity via the inverter 7 and given to the transistor TR2. To be

On the other hand, the transistor TR4 is in a conductive state when a positive voltage is applied to the base through the changeover switch 6. Therefore, in the motor 8, when the switching signal V _s is at high level, the transistors TR1 and TR4 are turned on and the power source V
It is energized from c to generate rotational force, and the switching signal V
_{When s} is at the low level, the transistors TR2 and TR4 are turned on and the dynamic braking state is set, so that the switching signal V _s
The driving force that changes according to the state of is generated or the braking state is set.

When the vehicle is moving backward, the switching signal V
_s has its polarity inverted via the exclusive OR circuit 5, and is given a positive voltage to the base via the changeover switch 6.
As a result, the transistor TR3 becomes conductive. Thus the motor 8 generates a reverse rotational force is energized from the power supply Vc becomes transistors TR2, TR3 are turned on when the switching signal V _s is the high level, the switching signal Vs the transistor TR1, TR3 at a low level Since the power is turned on and the dynamic braking state is set, the switching signal V
The reverse drive force that changes to the s state is generated or the braking state is set.

Now, in the circuit of FIG. 1, when the RC time constant in the integrating circuit 22 is increased to be a soft stop (in the present invention, the operation is particularly important at the time of stop, so description of the soft start is omitted). Even if the accelerator voltage Vacc is set to 0 by closing the throttle at the time of sudden stop, the signal voltage Vacc ^, does not become 0 immediately but has a certain value that gradually decreases, so that the motor 8 is generating a driving force. If you turn on the mechanical brake in this state,
The brake switch 9 linked to the mechanical brake lever (or pedal) is turned on. As a result, the electric charge accumulated in the capacitor C of the integrating circuit 22 is discharged through the resistance grounding circuit 10. Now, assuming that the value of the resistance ground circuit 10 is r, by setting the resistance R >> r,
The charge of the capacitor C is discharged in a time shorter than the time constant of the integrating circuit 22, the pulse width of the switching signal Vs becomes small, the driving force is rapidly reduced, and the dynamic braking is applied. In FIG. 2, the waveform (c) shows the time t _{2 to} t ₃ after the throttle is closed at the time t ₁ .
Shows the case of sudden braking in which the mechanical brake is turned on only once. The waveform (d) shows the mechanical brake t
_It shows the case of gentle braking applied intermittently several times at _{2 to} t ₃ , t _{4 to} t ₅ , and so on.

Therefore, in the embodiment shown in FIG.
By properly selecting the values of the resistances r, R, and C, it is possible to apply sudden braking when necessary by operating the mechanical brake, and lightly intermittently operate the mechanical brake to intermittently turn on the brake switch 9. When the switch is turned on, it is also possible to stop the gradual stop by intermittently applying the dynamic braking without operating the mechanical brake.

Here, in order to exert such a function more effectively, the brake switch 9 is actuated so that the brake switch 9 is operated before the brake begins to work by the operation of the mechanical brake. It is desirable to provide a certain amount of delay, that is, mechanical play between the turning on of the switch 9 and the start of actuation of the mechanical brake.

[0015]

Since the present invention is constructed and functions as described above, according to this, the brake switch operates in priority to the braking operation of the mechanical brake, and at the same time, the motor drive control section operates immediately in response to the operation. Therefore, even when the accelerator is being operated, it is possible to effectively switch to the braking mode, especially the dynamic braking, without applying a load to the motor, and set the power with the soft stop function.
Even in a moving vehicle, it is possible to provide a practical braking control device for an electric vehicle that has never been used, in which sudden braking can be applied whenever necessary without applying a load accompanying the brake to the motor.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a relation of signals of respective parts in the circuit diagram shown in FIG.

FIG. 3 (a) is a diagram showing a change in accelerator voltage caused by a throttle operation, and FIG. 3 (b) is a diagram showing an output waveform of an accelerator signal integrating circuit.

[Explanation of symbols]

 9 Brake switch 10 Resistance grounding circuit 20 Accelerator voltage output circuit section 21 Motor drive control section 22 Accelerator signal integration circuit

Claims (1)

[Scope of utility model registration request] 1. An accelerator voltage output circuit section 20 for generating a predetermined accelerator voltage according to a throttle operation amount, and a driving force for a motor according to the magnitude of an accelerator voltage output from the accelerator voltage output circuit section 20. A motor drive control unit 21 for generating or causing the motor to perform dynamic braking.
And an accelerator signal integrating circuit 22 provided between the motor drive control unit 21 and the accelerator voltage output circuit unit 20 for converting a rapid change of the accelerator voltage into a slow change and outputting the same, and the vicinity of the throttle. And a brake switch 9 which is operated by being urged by the operation of a mechanical brake operator provided in the motor drive controller, the brake switch 9 being connected in parallel to the capacitor portion of the accelerator signal integrating circuit 22. 21, in response to said operation of the brake switch 9 has a function to set the motor to the power generation braking state, the brake switch 9, the braking operation of the Mechanica Le braking in the operation sequence of the operation member for the mechanical brake Of the brake switch 9
There is no mechanical play between on and mechanical brake activation.
A braking control device for an electric vehicle, characterized in that the braking control device is connected to the mechanical brake manipulator.