JP2011050190A - Motor system and motor control circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor system capable of reducing the number of power supply lines. <P>SOLUTION: A motor system 10 is provided between a power source Ba for supplying power to a motor M and the motor M. and includes a first transistor 22 for driving the motor M of a motor unit 30; a second transistor 23 which is connected between the first transistor 22 and the ground and is connected in parallel to the motor unit 30; and a control part 21 which controls switching of the first and second transistors 22 and 23, in response to a motor output signal AS according to the rotation of the motor M. Supplying of power from the first transistor 22 to the motor M is performed by way of a power supply line L1. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a motor system and a motor control circuit, and more particularly to weight reduction of the motor system.

  Conventionally, as an example of a motor system, a wiper motor speed control is performed in a wiper motor system using a relay in a motor control circuit (see Patent Document 1). An example of a wiper motor system using such a conventional relay is shown in FIG. The wiper motor system 50 of FIG. 4 has a two-stage speed change function and an automatic stop function of a motor (wiper).

  In FIG. 4, when the motor M is driven at high speed (HI), the movable piece 62a of the main relay 62 is connected to the fixed contact 62c, and the movable piece 63a of the high speed / low speed (HI / LO) switching relay 63 is fixed to the fixed contact 63b. Connected to. At this time, the motor driving current is supplied to the motor M via the battery Ba, the main relay 62, the HI / LO switching relay 63 and the power supply line L4, and the high speed (HI) terminal J1 of the motor unit 70.

  When the wiper is driven at low speed (LO), the movable piece 62a of the main relay 62 is connected to the fixed contact 62c, and the movable piece 63a of the high speed / low speed (HI / LO) switching relay 63 is connected to the fixed contact 63c. The At this time, the motor drive current is supplied to the motor M via the battery Ba, the main relay 62, the HI / LO switching relay 63 and the power supply line L5, and the low speed (LO) terminal J2 of the motor unit 70.

  When the wiper SW (switch) is turned off after the wiper high speed (HI) driving, the movable piece 62a of the main relay 62 is connected to the fixed contact 62b, and the movable piece 63a of the HI / LO switching relay 63 is connected to the fixed contact 63b. The At this time, the motor drive current includes the battery Ba, the power supply line L3, the AS + B terminal of the motor unit 70, the fixed contact 31b and the movable piece 31a of the auto stop SW (switch) 31, the power supply line L6, the HI / LO switching relay 63, The electric power is supplied to the motor M through the main relay 62, the connection line L4, and the high speed (HI) terminal J1 of the motor unit 70.

  Further, when the motor M is stopped, as shown in FIG. 4, the movable piece 62a of the main relay 62 is connected to the fixed contact 62b, and the movable piece 63a of the HI / LO switching relay 63 is connected to the fixed contact 63b. At this time, since the movable piece 31a of the auto stop SW 31 is connected to the fixed contact 31c, the HI terminal of the motor unit 70 is short-circuited to the ground.

Japanese Patent Laid-Open No. 9-30374

  However, in the conventional wiper motor system using the relays 62 and 63, at least four power supply lines (L3 to L6) are used, which is a factor that increases the weight of the wiper motor system. It was. Therefore, a motor system that can reduce the number of power supply lines has been desired in order to reduce the vehicle weight and the manufacturing process, particularly in a motor system mounted on a vehicle such as a wiper motor system.

  The present invention has been completed based on the above circumstances, and an object thereof is to provide a motor system and a motor control circuit capable of reducing the number of power supply lines.

  As means for achieving the above object, a motor system according to a first aspect of the present invention outputs a motor, a motor input terminal for supplying electric power to the motor, and a motor output signal corresponding to the rotation of the motor. In a motor system including a motor unit having a motor output terminal, a first transistor that is provided between a power source that supplies electric power to the motor and the motor, drives the motor, the first transistor, and a ground And a second terminal connected in parallel with the motor unit, and a receiving terminal for receiving the motor output signal, and switching of the first and second transistors according to the motor output signal A control unit for controlling the power supply, a pull-up resistor connected between the power source and the receiving terminal, and the first transistor A first terminal connected between the register and the second transistor; a second terminal connected to the receiving terminal of the control unit; and a power supply line connecting the first terminal and the motor input terminal. And a signal line connecting the second terminal and the motor output terminal.

  According to this configuration, the motor can be driven and controlled by connecting the motor unit and the motor control circuit that controls driving of the motor by the single power supply line and the single signal line. Therefore, the number of wires between the motor unit and the motor control circuit can be reduced, and as a result, the weight and cost of the motor system can be reduced.

According to a second aspect of the present invention, in the motor system according to the first aspect, the control unit turns off the second transistor and controls the control terminal of the first transistor with a PWM signal when the motor is driven. The motor system according to claim 1, wherein the motor is driven in accordance with a duty ratio of the PWM signal, and the first transistor is turned off and the second transistor is turned on when the motor is stopped.
According to this configuration, the rotational speed control of the motor can be performed simply and preferably by changing the duty ratio of the PWM signal. In addition, the motor can be suitably stopped.

A third invention is the motor system of the first or second invention, wherein the motor system is mounted on a vehicle and drives a wiper of the vehicle, and the motor unit is a rotation of the motor. The auto stop switch is a movable piece connected to the motor output terminal, the movable piece rotating in conjunction with the rotation shaft of the motor, and a fixed piece connected to the ground. And a fixed contact that is connected to the movable piece when the motor is in a stop position.
According to this configuration, in the wiper motor system mounted on the vehicle, the number of wires between the motor unit and the motor control circuit can be reduced, and as a result, the weight and cost of the wiper motor system can be reduced. it can.

According to a fourth aspect of the present invention, in the motor system according to any one of the first to third aspects, the motor system further includes a timer for measuring a driving time of the motor, and the control unit outputs the motor output signal to the motor output signal. Based on this, when the measured time of the timer exceeds a threshold value, the locked state of the motor is detected.
According to this configuration, in a state where the number of wires between the motor unit and the motor control circuit is reduced, the locked state of the motor can also be detected suitably.

  As another means for achieving the above object, a motor control circuit according to a fifth aspect of the present invention is a motor, a motor input terminal for supplying power to the motor, and a rotation of the motor. A motor control circuit for controlling a motor unit having a motor output terminal for outputting a motor output signal, comprising: a first transistor for supplying electric power to the motor to drive the motor; and a first transistor and a ground A second transistor connected in parallel with the motor unit and a receiving terminal for receiving the motor output signal, and controls switching of the first and second transistors according to the motor output signal A control unit, a pull-up resistor connected between the power source and the receiving terminal, the first transistor and the second transistor A first terminal connected to the motor input terminal via a predetermined power supply line when the motor control circuit is connected to the motor unit; A second terminal connected to the receiving terminal of the control unit, and a second terminal connected to the motor output terminal when the motor control circuit is connected to the motor unit.

  According to this configuration, when the motor unit is driven using the motor control circuit, the motor control circuit and the motor unit are connected by one power supply line and one signal line, and the motor is The drive can be controlled. Therefore, the number of wires between the motor unit and the motor control circuit can be reduced, and as a result, the weight and cost of the motor system can be reduced. In particular, when the motor system is a wiper motor system mounted on a vehicle, the weight and cost of the vehicle can be reduced.

  According to the motor system and the motor control circuit of the present invention, the number of power supply lines from the motor control circuit to the motor can be reduced.

1 is a schematic block diagram of a motor system according to an embodiment of the present invention. Block diagram showing the state of the motor system when the motor is stopped Flow chart showing processing relating to motor drive control Schematic block diagram of a conventional motor system

<Embodiment>
An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic block diagram of a motor system according to an embodiment of the present invention, and shows a state during HI or LO speed control. FIG. 2 is a block diagram showing a state when the motor system is stopped. FIG. 3 is a flowchart showing processing related to motor drive control.

  In the present embodiment, an example is shown in which the motor system according to the present invention is applied to a wiper motor system that is mounted on a vehicle and that drives a wiper of the vehicle with electric power from a battery. Here, it is assumed that the wiper motor system has a two-stage shift function of HI and LO and an auto-stop function of the motor (wiper), similarly to the conventional wiper motor system shown in FIG.

1. Configuration of Wiper Motor System The wiper motor system 10 generally includes a motor control circuit 20 and a motor unit 30.
The motor unit 30 includes a motor M, a motor input terminal J1, an auto stop switch output terminal (motor output terminal) ASSI, and an auto stop switch 31. The electric power from the battery Ba is supplied to the motor M through the motor input terminal J1. Further, the motor output terminal ASSI outputs an auto stop switch output signal (motor output signal) AS corresponding to the rotation of the motor M, specifically, the position of the rotation shaft of the motor M.

  The auto stop switch 31 is a switch for automatically moving the motor M (wiper) to a stop position when a wiper switch (not shown) is turned off, and includes a movable piece 31a and two fixed contacts 31b and 31c. Including. The movable piece 31a is connected to the motor output terminal ASSI, and rotates in conjunction with the rotation shaft of the motor M, thereby contacting the fixed contact 31b or the fixed contact 31c.

  Specifically, when the motor M is not at the stop position, the movable piece 31a contacts the fixed contact 31b, and when the motor M is at the stop position, the movable piece 31a contacts the fixed contact 31c. The fixed contact 31b is not connected anywhere (NC state), and the fixed contact 31c is connected to the ground. Therefore, when the motor M is not in the stop position, the signal level of the motor output signal AS becomes a high level by the pull-up resistor 24 of the FET control circuit 21. On the other hand, when the motor M is at the stop position, the signal level of the motor output signal AS is low.

  The motor control circuit 20 includes a motor unit 30 including an FET control circuit (an example of a control unit) 21, a main FET (field effect transistor) 22, a brake FET 23, a pull-up resistor 24, and first and second terminals T1 and T2. Control.

  The main FET (an example of “first transistor”) 22 is an N-channel MOSFET here. The drain of the main FET 22 is connected to the battery Ba via the fuse F, and the source thereof is connected to the first terminal T1 and the drain of the brake FET 23. The main FET 22 drives the motor M by supplying electric power from the battery Ba to the motor M by controlling the gate (corresponding to a “control terminal”) by the FET control circuit 21.

  The brake FET (an example of a “second transistor”) 23 is an N-channel MOSFET here, like the main FET 22, and is connected between the main FET 22 and the ground. The drain of the brake FET 23 is connected to the first terminal T1 and the source of the main FET 22, and the source is connected to the ground. The brake FET 23 is turned on when the motor M reaches the stop position by the gate control by the FET control circuit 21 to stop the motor M. That is, when the motor M reaches the stop position, the movable piece 31a of the auto stop switch 31 comes into contact with the fixed contact 31c and is connected to the ground, whereby the brake FET 23 is turned on, so that both ends of the motor M are short-circuited. As a result, the motor M is braked and the motor M is completely stopped.

  The FET control circuit 21 includes a CPU, for example, and has a reception terminal 21 a that receives the motor output signal AS from the auto stop switch 31. The FET control circuit (CPU) 21 controls the main and brake FETs 22 and 23 according to the motor output signal AS or the wiper switch (SW) signal. Further, the FET control circuit 21 includes a timer 21b that measures the time for driving the wiper. The FET control circuit 21 does not include a CPU, and may be configured by, for example, an ASIC (application-specific integrated circuit).

  The first terminal T1 is connected between the main FET 22 and the brake FET 23, specifically, a connection line connecting the source of the main FET 22 and the drain of the brake FET 23 via a predetermined wiring. The first terminal T1 is connected to the motor input terminal J1 of the motor unit 30 through the power supply line L1.

  The second terminal T2 is connected to the receiving terminal 21a of the FET control circuit 21 via a predetermined wiring, and is connected to the motor output terminal ASSI of the motor unit 30 via the signal line L2.

2. Next, the wiper driving operation by the wiper motor system 10 will be described.
2-1. During HI or LO operation As shown in FIG. 1, when the wiper (motor) operates at a high speed (HI) or at a low speed (LO), the FET control circuit 21 controls the main FET 22 with a PWM (pulse width modulation) signal. Control. At that time, the FET control circuit 21 appropriately changes the duty ratio (pulse width) of the PWM signal in accordance with the speed of the motor M, that is, the operation speed of the wiper. For example, when the wiper is operated at high speed (HI), the motor M is DC driven with a duty ratio of 100%.

  On the other hand, when the wiper is operated at a low speed (LO), as shown in FIG. 1, the motor M is PWM driven with a duty ratio of, for example, 50%. When driving the motor M, the FET control circuit 21 turns off the brake FET 23. In the configuration of the present embodiment, by appropriately setting the duty ratio, the wiper (motor) speed can be set in multiple stages, not limited to two stages in HI and LO. Further, it is possible to use a motor M that does not have an HI / LO terminal individually.

2-2. When the wiper SW is off When the wiper SW signal is turned off in order to stop the operation of the wiper, the FET control circuit 21 returns the main FET 22 to return the wiper to the stop position when the motor M has not yet reached the stop position. Continue driving. That is, the FET control circuit 21 continues to drive the main FET 22 when the movable segment 31a of the auto stop switch 31 does not contact the fixed contact 31c and the motor output signal AS is high.

2-3. When the wiper is stopped Thereafter, the FET control circuit 21 detects the motor output signal AS every predetermined time. When the motor output signal AS becomes low, the FET control circuit 21 turns off the main FET 22 and turns on the brake FET 23 to stop the motor M. That is, in this case, when the motor M reaches the stop position, the movable segment 31a of the auto stop switch 31 contacts the fixed contact 31c in conjunction with it, and the motor output signal AS becomes low. At that time, both ends of the motor M are short-circuited, whereby the motor M is braked and the motor M is completely stopped.

3. Processing Related to Motor Drive Control Next, each process related to motor drive control will be described with reference to the flowchart of FIG. Each process of motor driving is started by a motor driving command, that is, when the wiper SW signal is turned on. The motor drive control process is executed by, for example, a CPU (not shown) of the FET control circuit 21 according to a predetermined program.

  In step S100 of FIG. 3, the FET control circuit (CPU) 21 clears the count time TC by the timer 21b to zero. Next, in step S105, for example, it is determined whether the drive command is a high speed (HI) drive command. If it is a HI drive command (S105: YES), the CPU turns on the main FET 22 to drive the motor M in a direct current (step S110). On the other hand, if the drive command is not a HI drive command (S105: NO), that is, if it is a LO drive command, the CPU turns on the main FET 22 and PWM drives the motor M with a predetermined duty ratio (step S115).

  Next, in step S120, it is determined whether a motor drive stop command is received, that is, whether the wiper SW is turned off. If it is determined that the motor drive stop command has been received (S120: YES), it is determined in step S130 whether the motor M is in the motor stop position.

  When it is determined that the motor M is at the motor stop position (S130: YES), the process proceeds to step S150. On the other hand, if it is determined that the motor M is not at the motor stop position (S130: NO), it is determined in step S132 whether the count time TC by the timer 21b has exceeded a predetermined threshold Cth.

  When it is determined that the count time TC of the timer 21b does not exceed the threshold value Cth (S132: NO), the process returns to step S130. On the other hand, when it is determined that the count value TC of the timer exceeds the count threshold Cth (S132: YES), motor lock is detected (step S134). This is because the motor M is not in the motor stop position after the predetermined time Cth, and therefore, for example, a twig or the like is caught in the wiper, and the locked state of the motor M is detected. Here, the count threshold Cth is set, for example, as the time until the motor M moves away from the stop position and returns to the stop position in the normal operation state of the motor M, that is, one cycle of the wiper drive. The Note that the count threshold Cth is not limited to this, and may be set, for example, as two or three cycles of wiper driving, or may be set to a predetermined time that does not depend on the wiper cycle.

  Returning to step S120, if it is determined that the motor drive stop command has not been received (S120: NO), it is determined in step S140 whether the motor M is in the motor stop position. When it is determined that the motor M is at the motor stop position (S140: YES), the process returns to step S100 to operate the wiper again. On the other hand, if it is determined that the motor M is not currently at the motor stop position (S140: NO), it is determined in step S142 whether the count time TC by the timer 21b has exceeded the count threshold Cth, as in step S132. .

  When it is determined that the count time TC of the timer 21b does not exceed the count threshold Cth (S142: NO), the process returns to step S120. On the other hand, when it is determined that the count value TC of the timer 21b exceeds the threshold value Cth (S142: YES), motor lock is detected (step S144). This is because the motor M exceeds the threshold value Cth and does not return to the motor stop position, so the motor M is considered to be in a locked state on the way.

  Next, in step S150, the main FET 22 is turned off. Then, the brake FET 23 is turned on (step S155), and the motor M is stopped (step S160).

4). Effects of the embodiment In the present embodiment, the motor unit 30 and the motor control circuit 20 are connected by a single power supply line L1 and a single signal line L2, and a multi-stage speed change function of a motor (wiper) is achieved. And the wiper motor system 10 which has an auto stop function is realizable. That is, a function equivalent to that of the conventional wiper motor system shown in FIG. 4 can be performed by reducing the number of wires between the motor unit 30 and the motor control circuit 20. Therefore, the weight and cost of the wiper motor system 10 can be reduced. That leads to a reduction in vehicle weight and cost.

Further, the rotation speed control of the motor M can be performed simply and preferably by changing the duty ratio of the PWM signal.
Further, the locked state of the wiper motor M can be suitably detected using the timer 21b and the auto stop switch output signal (motor output signal) AS.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.

  (1) In the above embodiment, an example in which the motor system is applied to a wiper motor system mounted on a vehicle has been described, but the present invention is not limited thereto. The motor system according to the present invention includes a motor unit that outputs a motor output signal according to the rotation of the motor, and can be applied to any motor system that controls the motor according to the motor output signal.

(2) In the above embodiment, an example in which the “motor lock detection process” is performed by the motor system has been described, but the “motor lock detection process” may be omitted.
(3) In the above-described embodiment, an example in which the first transistor and the second transistor are N-channel MOSFETs has been described. For example, the first and second transistors may be P-channel MOSFETs or bipolar transistors. When the first and second transistors are bipolar transistors, the control terminal is a base.

10. Wiper motor system (motor system)
20 ... Motor control circuit 21 ... FET control circuit (control unit)
21a: Reception terminal 22 ... Main FET (first transistor)
23 ... Brake FET (second transistor)
24 ... Pull-up resistor 30 ... Motor unit 31 ... Auto stop switch AS ... Auto stop switch output signal (motor output signal)
ASSI: Auto stop switch output terminal (motor output terminal)
J1 ... Motor input terminal L1 ... Power supply line L2 ... Signal line M ... Motor

Claims (8)

In a motor system comprising a motor, a motor unit having a motor, a motor input terminal for supplying electric power to the motor, and a motor output terminal for outputting a motor output signal corresponding to the rotation of the motor.
A first transistor that is provided between a power source that supplies power to the motor and the motor, and that drives the motor;
A second transistor connected between the first transistor and the ground and connected in parallel with the motor unit;
A pull-up resistor having a receiving terminal for receiving the motor output signal, and connected between the power source and the receiving terminal; a control unit that controls switching of the first and second transistors according to the motor output signal; When,
A first terminal connected between the first transistor and the second transistor;
A second terminal connected to the receiving terminal of the control unit;
A power supply line connecting the first terminal and the motor input terminal;
A signal line connecting the second terminal and the motor output terminal;
Motor system equipped with. The controller is
At the time of driving the motor, the second transistor is turned off, the control terminal of the first transistor is controlled by a PWM signal, and the motor is driven according to the duty ratio of the PWM signal,
The motor system according to claim 1, wherein when the motor is stopped, the first transistor is turned off and the second transistor is turned on. The motor system is a wiper motor system that is mounted on a vehicle and drives a wiper of the vehicle,
The motor unit includes an auto stop switch that switches according to the rotation of the motor,
The auto stop switch is
A movable piece connected to the motor output terminal and rotating in conjunction with a rotation shaft of the motor;
The motor system according to claim 1, further comprising a fixed contact connected to a ground and connected to the movable piece when the motor is at a stop position. The motor system further includes a timer for measuring the driving time of the motor,
4. The motor according to claim 1, wherein the control unit detects a lock state of the motor based on the motor output signal when the measured time of the timer exceeds a threshold value. 5. system. A motor control circuit for controlling a motor unit having a motor, a motor input terminal for supplying electric power to the motor, and a motor output terminal for outputting a motor output signal corresponding to the rotation of the motor;
A first transistor for supplying power to the motor to drive the motor;
A second transistor connected between the first transistor and the ground and connected in parallel with the motor unit;
A pull-up resistor having a receiving terminal for receiving the motor output signal, and connected between the power source and the receiving terminal; a control unit that controls switching of the first and second transistors according to the motor output signal; When,
A first terminal connected between the first transistor and the second transistor, and when the motor control circuit is connected to the motor unit, connected to the motor input terminal via a predetermined power supply line A first terminal to be
A second terminal connected to the receiving terminal of the control unit, and when the motor control circuit is connected to the motor unit, a second terminal connected to the motor output terminal;
Motor control circuit with The controller is
At the time of driving the motor, the second transistor is turned off, the control terminal of the first transistor is controlled by a PWM signal, and the motor is driven according to the duty ratio of the PWM signal,
The motor control circuit according to claim 5, wherein when the motor is stopped, the first transistor is turned off and the second transistor is turned on.   The motor control circuit according to claim 5 or 6, wherein the motor control circuit is a wiper motor control circuit that is mounted on a vehicle and drives a wiper of the vehicle. The motor control circuit further includes a timer for measuring the driving time of the motor,
The motor according to any one of claims 5 to 7, wherein the control unit detects a lock state of the motor when a measurement time of the timer exceeds a threshold based on the motor output signal. Control circuit.

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