JP3887307B2 - Electric motor drive device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a motor control means for outputting a pulse signal in which a combination of one on state and one off state is one cycle in accordance with a duty ratio, and an electric motor in accordance with the pulse signal from the motor control means. An electric motor drive comprising: a driving means for driving the electric motor; and a lock state determining means for determining a lock state of the electric motor based on a gradual decrease in the terminal voltage of the electric motor immediately after the end of the output of the pulse signal from the electric motor. It relates to the improvement of the apparatus.
[0002]
[Prior art]
Conventionally, it is already known that the locked state of an electric motor is determined according to the decrease or decrease of the terminal voltage immediately after the electric motor stops driving (see, for example, Patent Document 1), and the rotational speed of the electric motor. There is already known one that performs duty control on the operation of the electric motor in order to suppress the noise and reduce the operating noise (see, for example, Patent Document 2).
[0003]
[Patent Document 1]
Japanese Patent No. 2513323 [Patent Document 2]
Japanese Patent Laid-Open No. 2001-71877
[Problems to be solved by the invention]
Incidentally, in response to the motor drive request signal shown in FIG. 5 (a), a pulse signal is output from the electric motor control means as shown in FIG. 5 (b), and the terminal voltage of the electric motor is changed accordingly in FIG. 5 (c). However, when the electric motor is normal, the load of the electric motor is small, and when the drive is stopped, the inertial force keeps rotating for a relatively long time, so the terminal voltage of the electric motor is moderate. On the other hand, when the electric motor is in the locked state, the load on the electric motor is large, so that the terminal voltage of the electric motor rapidly decreases in accordance with the stop of driving. In view of this, when the time T1 until the terminal voltage immediately after the stop of driving is reduced to the set voltage VO is short, it is determined that the electric motor is in the locked state, and the electric motor is driven by the gradual decrease in the terminal voltage immediately after the stop of driving. The lock state is determined.
[0005]
However, in the prior art, a pulse signal in which the on state and the off state following the on state are one cycle is output from the motor control means, and the pulse output from the motor control means when the drive of the electric motor is stopped. Since the signal ends in the off state, the terminal voltage of the electric motor is relatively low, and it is difficult to accurately determine the lock state of the electric motor.
[0006]
The present invention has been made in view of such circumstances, and an object of the present invention is to provide an electric motor drive device that can accurately determine the lock state of an electric motor that is duty controlled.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is a motor control means for outputting a pulse signal according to a duty ratio, wherein a combination of one on state and one off state is one cycle; A drive means for driving the electric motor in response to a pulse signal from the motor control means, and a lock state of the electric motor based on a gradual decrease in the terminal voltage of the electric motor immediately after the end of the pulse signal output from the motor control means In the electric motor drive device comprising: a lock state determination unit that determines whether or not the motor control unit is a pulse signal in which at least when the drive of the electric motor is stopped, the first off state and the on state following the off state are one cycle. Is output.
[0008]
According to the configuration of the invention described in claim 1, since the pulse signal output from the motor control means ends in the ON state at least when the drive of the electric motor is stopped, the terminal voltage of the electric motor is relatively low. Since the electric motor lock state is determined based on a decrease in the terminal voltage from a relatively high value, the electric motor lock state can be accurately determined.
[0009]
According to a second aspect of the invention, in addition to the configuration of the first aspect of the invention, the motor control means maintains the on state for a predetermined time at the start of driving the electric motor, and then turns off the off state and the off state. The pulse signal is output with the ON state following one cycle as one cycle. According to such a configuration, it is possible to accurately determine the lock state of the electric motor, and at the start of driving the electric motor. Responsiveness can be improved.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on one embodiment of the present invention shown in the accompanying drawings.
[0011]
1 to 4 show an embodiment of the present invention, FIG. 1 is a hydraulic circuit diagram of a vehicle brake device, and FIG. 2 shows the configuration of an electronic control unit for controlling the rotational speed of an electric motor. FIG. 3 is a block diagram, FIG. 3 is a diagram showing a map of applied voltage and duty ratio, and FIG. 4 is a diagram showing changes in motor drive request signal, electric motor control pulse signal, and terminal voltage of the electric motor.
[0012]
First, in FIG. 1, a tandem master cylinder M is provided with first and second output ports 1A and 1B for generating brake fluid pressure in accordance with a pedaling force applied to a brake pedal P by a vehicle driver. Wheel brake 2A, right rear wheel wheel brake 2B, right front wheel wheel brake 2C and left rear wheel wheel brake 2D, and first and second individually connected to the first and second output ports 1A and 1B, respectively. A hydraulic pressure control device 4 is provided between the output hydraulic pressure passages 3A and 3B, and the first and second proportional pressure reducing valves 5A are provided between the hydraulic pressure control device 4 and the right and left rear wheel brakes 2B and 2D. , 5B are interposed.
[0013]
The hydraulic pressure control device 4 includes first, second, third, and third brakes respectively corresponding to the left front wheel brake 2A, the right rear wheel brake 2B, the right front wheel brake 2C, and the left rear wheel brake 2D. Fourth normally open solenoid valves 6A-6D, first, second, third and fourth check valves 7A-7D connected in parallel to the respective normally open solenoid valves 6A-6D, and the wheel brakes The first, second, third and fourth normally closed solenoid valves 8A to 8D individually corresponding to 2A to 2D, and the first and second individually corresponding to the first and second output hydraulic pressure paths 3A and 3B, respectively. The second reservoirs 9A and 9B, the plunger-type first and second pumps 10A and 10B connected to the first and second reservoirs 9A and 9B via the suction valves 11A and 11B, respectively, and both pumps 10A and 10B One common electric motor to drive Comprising a 2, the normally open solenoid valves 6A-6D, and an electronic control unit 16 for controlling the operation of the normally closed solenoid valve 8A~8D and the electric motor 12.
[0014]
The first normally open solenoid valve 6A is provided between the first output hydraulic pressure path 3A and the left front wheel brake 2A, and the second normally open solenoid valve 6B is provided with the first output hydraulic pressure path 3A and the first proportionality. The third normally open solenoid valve 6C is provided between the pressure reducing valve 5A, the second output hydraulic pressure passage 3B and the right front wheel brake 2C, and the fourth normally open solenoid valve 6D is provided with the second output. It is provided between the hydraulic pressure path 3B and the second proportional pressure reducing valve 5B.
[0015]
The first to fourth check valves 7A to 7D are connected in parallel to the normally open solenoid valves 6A to 6D so as to allow the flow of brake fluid from the corresponding wheel brakes 2A to 2D to the master cylinder M. Is done.
[0016]
The first normally closed solenoid valve 8A is provided between the left front wheel brake 2A and the first reservoir 9A, and the second normally closed solenoid valve 8B is provided between the first proportional pressure reducing valve 5A and the first reservoir 9A. The third normally closed solenoid valve 8C is provided between the right front wheel brake 2C and the second reservoir 9B, and the fourth normally closed solenoid valve 8D is provided between the second proportional pressure reducing valve 5B and the second reservoir 9B. Is provided.
[0017]
Such a hydraulic control device 4 communicates between the master cylinder M and the wheel brakes 2A to 2D and between the wheel brakes 2A to 2D and the reservoirs 9A and 9B at the time of normal braking in which each wheel is not likely to be locked. Cut off. That is, the normally open solenoid valves 6A to 6D are demagnetized and opened, and the normally closed solenoid valves 8A to 8D are demagnetized and closed, and output from the first output port 1A of the master cylinder M. The brake fluid pressure acts on the left front wheel brake 2A via the first normally open solenoid valve 6A, and for the right rear wheel via the second normally open solenoid valve 6B and the first proportional pressure reducing valve 5A. It acts on the wheel brake 2B. The brake hydraulic pressure output from the second output port 1B of the master cylinder M acts on the right front wheel brake 2C via the third normally open solenoid valve 6C, and the fourth normally open solenoid valve 6D and It acts on the left rear wheel wheel brake 2D via the second proportional pressure reducing valve 5B. When the wheel is about to enter the locked state during the brake, the hydraulic pressure control device 4 shuts off the master cylinder M and the wheel brakes 2A to 2D at the portion corresponding to the wheel about to enter the locked state. In addition, the wheel brakes 2A to 2D and the reservoirs 9A and 9B are communicated with each other. That is, among the first to fourth normally open solenoid valves 6A to 6D, the normally open solenoid valve corresponding to the wheel that is about to enter the locked state is excited and closed, and the first to fourth normally closed solenoid valves are excited. Among the solenoid valves 8A to 8D, the normally closed solenoid valve corresponding to the wheel is excited and opened. Thereby, a part of the brake fluid pressure of the wheel that is about to enter the locked state is absorbed by the first reservoir 9A or the second reservoir 9B, and the brake fluid pressure of the wheel that is about to enter the locked state is reduced. It will be.
[0018]
When the brake fluid pressure is kept constant, the fluid pressure control device 4 enters a state in which the wheel brakes 2A to 2D are disconnected from the master cylinder M and the reservoirs 9A and 9B. That is, the normally open solenoid valves 6A to 6D are excited and closed, and the normally closed solenoid valves 8A to 8D are demagnetized and closed. Further, when the brake fluid pressure is increased, the normally open solenoid valves 6A to 6D may be demagnetized and opened, and the normally closed solenoid valves 8A to 8D may be demagnetized and closed.
[0019]
Thus, the electronic control unit 16 controls the demagnetization and excitation of the normally open solenoid valves 6A to 6D and the normally closed solenoid valves 8A to 8D, so that braking can be efficiently performed without locking the wheels. it can.
[0020]
In FIG. 2, an electric motor 12 is connected to a battery 18 via a driving means 19 such as a relay, and the operation of the electric motor 12 is controlled by controlling the operation of the driving means 19 by a control unit 16. .
[0021]
The portion of the electronic control unit 16 that controls the operation of the electric motor 12 includes a duty ratio determining unit 21, a motor control unit 22, and a lock state determination unit 23.
[0022]
The applied voltage from the battery 18 to the electric motor 12 is detected by the voltage detecting means 20, and the applied voltage detected by the voltage detecting means 20 is input to the duty ratio determining means 21. That is, the duty ratio determining means 21 is preset with a duty ratio corresponding to the voltage applied to the electric motor 12 as shown in FIG. 3, and the duty ratio determining means 21 is detected by the voltage detecting means 20. The duty ratio of energization to the electric motor 12 according to the applied voltage is determined, for example, every 20 msec.
[0023]
The motor control means 22 sets a combination of one on state and one off state to 1 so as to duty-control energization from the battery 18 to the electric motor 12 at the duty ratio determined by the duty ratio determination means 21. A cycle pulse signal is output in accordance with the duty ratio, and one cycle is set to 20 msec, for example.
[0024]
In addition, the motor control means 22 responds to the motor drive request signal shown in FIG. 4 (a), and at least when the drive of the electric motor is stopped, the pulse signal with the first off state and the on state following the off state as one cycle. 4 (b), and when the drive of the electric motor 12 is started, the ON state is maintained for a predetermined time T2 (for example, 100 msec), and then the OFF state and the ON state following the OFF state are displayed. A pulse signal with one cycle is output. The drive means 19 drives the electric motor 12 in accordance with the pulse signal output from the motor control means 22, and the terminal voltage of the electric motor 12 changes as shown in FIG.
[0025]
The lock state determination unit 23 determines the lock state of the electric motor 12 based on the decrease or decrease of the terminal voltage of the electric motor 12 immediately after the output of the pulse signal from the motor control unit 22 is completed. ), It is determined that the electric motor 12 is in the locked state when the time T1 until the terminal voltage immediately after the stop of driving decreases to the set voltage VO is short.
[0026]
By the way, the electric motor 12 is driven only for a first fixed time when the vehicle speed becomes equal to or higher than a fixed vehicle speed at the start of traveling of the vehicle, and a second fixed time elapses from the last decompression during the antilock brake control. The lock state determination means 23 determines the lock state of the electric motor 12 when the drive of the electric motor 12 is stopped.
[0027]
Next, the operation of this embodiment will be described. Since the motor control means 22 outputs a pulse signal in which the first off state and the on state following the off state are one cycle at least when the drive of the electric motor 12 is stopped. When the driving of the electric motor 12 is stopped, the pulse signal output from the motor control means 22 ends in the ON state as shown in FIG. Therefore, the terminal voltage when the driving of the electric motor 12 is stopped is higher than that of the conventional one shown in FIG. 5C, and the time T1 required for the terminal voltage to decrease from the relatively high value to the set voltage VO. Since the lock state of the electric motor 12 is determined based on the time T1, the time T1 is set to be relatively large compared to the conventional one in which the pulse signal output from the motor control means ends when the drive of the electric motor 12 is stopped. Thus, the locked state of the electric motor 12 can be accurately determined.
[0028]
Further, the motor control means 22 outputs a pulse signal in which the OFF state and the ON state following the OFF state are set to one cycle after the ON state is maintained for a predetermined time T2 at the start of driving of the electric motor 12. Thus, the responsiveness at the start of driving of the electric motor 12 can be improved.
[0029]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. It is.
[0030]
【The invention's effect】
As described above, according to the first aspect of the present invention, the lock state of the electric motor can be accurately determined.
[0031]
According to the second aspect of the invention, it is possible to accurately determine the lock state of the electric motor, and it is possible to improve the responsiveness at the start of driving the electric motor.
[Brief description of the drawings]
FIG. 1 is a hydraulic circuit diagram of a vehicle brake device.
FIG. 2 is a block diagram showing a configuration of a part related to electric motor control in the electronic control unit.
FIG. 3 is a diagram showing a map of applied voltage and duty ratio.
FIG. 4 is a diagram showing changes in a motor drive request signal, an electric motor control pulse signal, and a terminal voltage of the electric motor.
FIG. 5 is a diagram corresponding to FIG. 4 of the related art.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 12 ... Electric motor 19 ... Drive means 22 ... Motor control means 23 ... Lock state determination means

Claims (2)

A motor control means (22) for outputting a pulse signal corresponding to a duty ratio with a combination of one on-state and one off-state as one cycle, and according to the pulse signal from the motor control means (22) The drive means (19) for driving the electric motor and the electric motor (12) based on the gradual decrease in the terminal voltage of the electric motor (12) immediately after the end of the pulse signal output from the motor control means (22). In the electric motor drive device including the lock state determination means (23) for determining the lock state, the motor control means (22) is in an initial OFF state and an OFF state at least when the drive of the electric motor (12) is stopped. An electric motor driving device that outputs a pulse signal in which the subsequent ON state is one cycle. The motor control means (22) outputs a pulse signal in which the ON state is maintained for a predetermined time at the start of driving of the electric motor (12) and then the OFF state and the ON state following the OFF state are set as one cycle. The electric motor driving device according to claim 1.

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