JPH04304177A - Motor controller - Google Patents

Abstract

PURPOSE:To start or stop a motor slowly by gradually increasing or decreasing power supply to the motor at the time of starting or stopping. CONSTITUTION:Upon turn ON of an operating switch 6, an NTC thermister 3, (a) contact of first bimetal switch 4 and a protective bimetal switch 5 are connected with an exciting coil 7 and thereby a current flows through a motor 2. Since the NTC thermister 3 has high initial resistance, the motor 2 current flows, while being limited, through (a) contact of the first bimetal switch 4 to the protective bimetal switch 5. The current increases gradually as the NTC thermister 3 is heated and the resistance thereof decreases gradually. Consequently, rotational speed of the motor 2 increases gradually. Similarly, when the operating switch is turned OFF, rotational speed of the motor 2 is decreased gradually to zero. According to the invention, electromagnetic noise is suppressed while furthermore downsizing and cost reduction are realized.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control device for controlling a drive device such as an opening/closing mechanism.

0002

2. Description of the Related Art Conventionally, a motor control device for a motor mounted on a vehicle has been proposed as shown in Japanese Utility Model Application Publication No. 17438/1983. In this motor control device, P
The rotational speed of the motor is controlled by WM control to adjust, for example, the position of a car seat. In other words, as shown in Figure 4, the normal operation switch is turned on and off.
By turning it off, it is possible to suppress the inrush current that flows when the motor is directly controlled. As a result, it is possible to minimize the impact caused by the sudden movement or stopping of the seat on the occupant sitting on the seat.

0003

[Problem to be solved by the invention] However, PWM
Since the motor control device configured by the control uses power transistors, the heat dissipation structure of the power transistors becomes large, resulting in an increase in the size of the motor control device and an increase in cost due to the use of the power transistors. Further, as shown in FIG. 3, pulse voltage is applied when starting and stopping the motor by PWM control, thereby preventing inrush current. However, this pulsed voltage generates electromagnetic noise, which has a negative effect on other equipment (car radios, etc.).

The present invention has been made to solve the above-mentioned problems, and its purpose is to provide a motor control device that can prevent the generation of electromagnetic noise, as well as reduce size and cost. It is in.

[0005]

Means for Solving the Problems In order to solve the above problems, the present invention provides a motor control device that controls a drive device by driving a motor connected to a power supply based on an operation switch. a rise control means for gradually increasing the rotational speed of the motor by continuously varying the supply power of the motor in an increasing direction; and after the operation of the rise control means, the increase based on the power supply; A switching control means disables the control means and connects the motor directly to the power supply, and the power supply to the motor is continuously varied in a decreasing direction by turning off the operation switch, and the rotation speed of the motor is gradually reduced. The gist of the present invention is to include a deceleration and stop means for stopping the deceleration and stop means, and an operation control means for setting the deceleration and stop means to a state where the operation can be performed after the operation switch is turned off when the operation switch is turned on.

[0006]

[Operation] When the operation switch is turned on, the motor connected to the power source starts rotating. At this time, the power supplied to the motor is gradually increased by the rise control means, and the rotational speed of the motor is increased. Thereafter, the switching control means disables the control means based on the power supply, and the motor is directly driven by the power supply. Further, the operation control means makes the deceleration and stop means operable based on the operation of the rise control means.

[0007] When the operation switch is turned off, the deceleration and stop means decreases the power supplied to the motor, and the rotational speed of the motor is gradually reduced and stopped. Therefore, since the power supplied to the motor gradually increases and decreases when starting and stopping, the rotation of the motor can be started and stopped slowly.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in a motor control device for controlling a motor of an electric seat of an automobile will be described below with reference to FIGS. 1 and 2. As shown in FIG. 1, a motor 2 connected to a DC power source 1 has an N
TC (Negative Temperature)
Coefficient) Thermistor 3 is connected. This NTC thermistor 3 has a large initial resistance value,
It has a negative temperature coefficient. Changes in the resistance value of the NTC thermistor 3 depend on internal heat generation, and when the NTC thermistor 3 generates heat, the internal resistance value decreases and current flows more easily.

The NTC thermistor 3 is connected to a protective bimetal switch 5 via an a contact of a first bimetal switch 4 serving as a switching control means. Also, the first
The b contact of the bimetal switch 4 is connected to the motor 2 and NTC.
It is connected to a node N1 between the thermistor 3 and the thermistor 3. The contact 4a of the first bimetal switch 4 is usually
is connected to the a contact side, and is switched to the b contact side when the contact 4a is deformed due to heat generation. Further, the protective bimetal switch 5 is normally in a closed state, but becomes open when an overcurrent flows through the motor 2 to protect the motor 2.

The protective bimetallic switch 5 is connected to an operating switch 6, and the operating switch 6 is connected via an excitation coil 7 as an operation control means. By turning on the operation switch 6, the motor 2 can be driven and controlled. or,
A PTC (Positive Temperature Control) is provided as a deceleration and stop means for the operation switch 6 and the excitation coil 7.
A thermistor 8 and a second bimetal switch 9 are connected in parallel. The second bimetal switch 9 is normally in an open state. This PTC thermistor 8 has a small initial resistance value,
It has a positive temperature coefficient. Changes in the resistance value of the PTC thermistor 8 depend on internal heat generation, and when the PTC thermistor 8 generates heat, the internal resistance value increases, making it difficult for current to flow.

The second bimetal switch 9 is disposed close to the excitation coil 7, and when current flows through the excitation coil 7, the second bimetal switch 9 is closed due to its magnetic force. At this time, although the current becomes difficult to flow due to the initial resistance value of the PTC thermistor 8, a small amount of current flows through the PTC thermistor 8 and the second bimetal switch 9. Therefore, the second
The bimetal switch 9 generates heat and maintains a closed circuit state. Even if current no longer flows through the excitation coil 7 due to the OFF operation of the operation switch 6, the second bimetal switch 9 continues to be closed. Then, when the second bimetal switch 9 itself no longer generates heat and cools down, it becomes an open circuit state.

Next, the operation of the motor control device configured as described above will be explained. First, as shown in FIG. 2, by turning on the operation switch 6, the NTC thermistor 3, the a contact of the first bimetal switch 4, the protection bimetal switch 5, and the excitation coil 7 are connected, and current begins to flow to the motor 2. . In addition, at this time, the excitation coil 7
The second bimetal switch 9 is in a closed circuit state due to the magnetic force of
A TC thermistor 8 and a second bimetal switch 9 are connected in parallel. However, since the PTC thermistor 8 has a slight initial resistance value, current flows through most of the excitation coil 7 side. Further, since a small amount of current flows through the second bimetal switch 9, the second bimetal switch 9 generates heat and maintains the closed circuit state by itself.

On the other hand, since the initial resistance value of the NTC thermistor 3 is large, the current flowing to the motor 2 is limited as shown in FIG. flows to the side. Then, the NTC thermistor 3 begins to generate heat, and as the resistance value of the NTC thermistor 3 gradually decreases, the current increases. Therefore, the rotation speed of the motor 2 gradually increases as the current increases due to the decrease in resistance value. Thereby, the position of a car seat (not shown) connected to the motor 2 can be gradually changed from a low speed state.

Furthermore, due to the increase in current, the contact 4a of the first bimetal switch 4 generates heat and is thermally deformed over a certain period of time, so that the contact 4a is connected to the b contact side. Therefore, N
Since the TC thermistor 3 is in an open state and the motor 2 is directly connected to the first bimetal switch 4, a constant current flows. Thereby, the position of the seat connected to the motor 2 can be changed at a constant speed.

Thereafter, when the operation switch 6 is turned off, all the current begins to flow through the PTC thermistor 8 and the second bimetal switch 9. At this time, the excitation coil 7
Although the magnetic force is lost, the second bimetal switch 9 maintains the closed circuit state due to self-heating. In this state, the PTC thermistor 8 begins to generate heat. For this reason, P.T.
The resistance value of the C thermistor 8 gradually increases, and the current is gradually limited. Therefore, since current no longer flows to the second bimetallic switch 9 due to the PTC thermistor 8, the second bimetal switch 9 is cooled down for a certain period of time and becomes an open circuit state, so that no current flows. As a result, the motor 2 is stopped slowly, and as a result, the seat position can be changed from a constant speed to a gradually low speed state, and then stopped.

Therefore, in this embodiment, when the operation switch 6 is turned on, the rise of the current flowing through the motor 2,
In other words, the inrush current can be suppressed by the resistance of the NTC thermistor 3, and the rotational speed of the motor 2 can be gradually increased. As a result, sudden movement of the seat when the operation switch 6 is turned on can be prevented, and the impact on the passenger can be alleviated.

Similarly, a PTC thermistor 8 detects the fall of the current flowing through the motor 2 when the operation switch 6 is turned off.
The rotational speed of the motor 2 can be gradually reduced and stopped due to the resistance of the motor 2. As a result, it is possible to prevent the seat from suddenly stopping when the operation switch 6 is turned off, and to reduce the impact on the passenger.

Furthermore, since the NTC thermistor 3 and the PTC thermistor 8 are cheaper than power transistors, the manufacturing cost of the motor control device can be reduced. Furthermore, since there is no need to provide a heat dissipation structure, the motor control device can be downsized. Unlike PWM control, a pulse waveform voltage is not applied to the motor when the operation switch 6 is turned on and off, so no rush current flows through the motor. That is, since the voltage and current applied to the motor are gradually and continuously raised and lowered to prevent inrush current, generation of electromagnetic noise can be prevented. As a result,
It is possible to prevent electromagnetic noise from adversely affecting other equipment (car radios), etc.

In this embodiment, the case where the motor rotates only in the forward direction has been explained, but even in a circuit where the direction of the current changes due to forward and reverse rotation, in this embodiment, the direction of the current is changed. It works regardless and has the same effect as above.

[0020]

As described in detail above, the present invention has the excellent effect of preventing the generation of electromagnetic noise and reducing the size and cost of the entire device.

[Brief explanation of drawings]

FIG. 1 is an electrical circuit diagram of a motor control device according to the present invention.

FIG. 2 is a characteristic diagram showing the characteristics of the current and voltage flowing to the motor by the motor control device.

FIG. 3 is a characteristic diagram showing characteristics of current and voltage flowing to a motor by a conventional motor control device.

FIG. 4 is a characteristic diagram showing that an inrush current flows through the motor when the motor is directly driven by a power source.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1... DC power supply, 2... Motor, 3... NTC thermistor as a rise control means, 4... First bimetal switch as a switching control means, 6... Operation switch, 7... Excitation coil as an operation control means, 8... Deceleration stop PTC as a tool
Thermistor, 9...Second bimetal switch as deceleration and stop means

Claims (1)

[Claims] 1. A motor control device that controls a drive device by driving a motor connected to a power source based on an operation switch, wherein the power supply to the motor is continuously increased by turning on the operation switch. an increase control means for gradually increasing the rotational speed of the motor by making it variable; and a switching control for disabling the increase control means based on the power supply and directly connecting the motor to a power source after the operation of the increase control means. means, a deceleration and stop means for gradually reducing and stopping the rotational speed of the motor by continuously varying the power supply to the motor in a decreasing direction by turning off the operation switch; 1. A motor control device comprising: operation control means for setting the operation to a state in which operation is enabled after the operation switch is turned off when the switch is turned on.