JP3181461B2 - Motor drive device with safety function - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor driving device having a safety function, and more particularly, to an object such as a part of a body being pinched while a movable mechanism movable by a motor is moving. The present invention relates to a motor driving device having a safety function for immediately stopping driving of a motor when the motor driving device stops.

[0002]

2. Description of the Related Art Conventionally, a motor drive device having a safety function is used for a power window, a sunroof, and a power seat of an automobile. When a part of the body or another object is pinched, the driving of the motor is stopped to protect the pinched part or to prevent the motor from burning due to overcurrent flow. ing.

FIG. 4 is a circuit diagram showing an outline of an example of a motor driving device having such a known safety function.

In FIG. 4, a motor 31 is connected to a first relay 32 and / or a second relay 33, and by switching these relays 32 and 33, a current flows in opposite directions, or the current flows. It is connected so that flow stops. The first relay 32 and the second relay 33
The first inverter 34 and the second inverter 3 respectively
5 is connected to the output side of the microprocessor unit 38. Further, it is connected to a microprocessor unit 38 via a differential amplifier 37 for detecting a voltage between both terminals of the current value detecting resistor 36. The operation switch 39 is for moving a movable mechanism described later.
It is provided for each moving direction of the movable mechanism and is connected to the microprocessor unit 38. The current flowing through the motor 31 is a current value detection resistor 36 connected in series to the motor 31.
Flow through. First relay 32 and second relay 33
Are energized by the drive output of the microprocessor unit 38 supplied via the first inverter 34 and the second inverter 35, respectively.
The terminal voltage at 6 is detected by the differential amplifier 37 and supplied to the microprocessor unit 38.

Although not shown in FIG. 4, the microprocessor unit 38 includes a motor drive control device for controlling the rotation and stop of the motor 31 and the rotation direction thereof, and a current change per unit time of the motor 31. The measured current change amount is compared with a preset preset value, and when the current change amount exceeds the preset value, a current measurement comparison for supplying a detection output to the motor drive device is performed. Built-in device. Here, the microprocessor unit 38 performs data processing digitally, and analog data such as input voltage is converted into digital data, and then required processing is performed. Further, although not shown in FIG. 4, the motor 31 is configured to move a movable mechanism such as a window, a sunroof, and a seat of the vehicle when the motor 31 is driven.

[0006] The motor drive device having the safety function according to the above configuration operates as follows.

When it is not necessary to move the movable mechanism, for example, to open or close the window, the microprocessor unit 38 is opened (OPEN) and closed (CLOS).
E) When the output of the terminal is set to the low level voltage (L), the low level voltage (L) is converted to the high level voltage (H) by the first inverter 34 and the second inverter 35,
This high level voltage (H) is supplied to one ends of the first relay 32 and the second relay 33. On the other hand, the first relay 3
Since the high-level voltage (H) is constantly supplied to the other ends of the second and second relays 33, the first relay 32 and the second relay 33 are not energized, and their movable contacts are one-sided. Are switched to the fixed contact side (lower side in FIG. 4), and no current flows through the motor 31. Therefore, the movable mechanism, for example, the window does not move at all.

Next, when opening a movable mechanism, for example, a window, the window opening operation switch 39 is pressed to open the microprocessor unit 38 (OPE).
N) Only the output of the terminal is switched from the low level voltage (L) to the high level voltage (H). In this case, the high-level voltage (H) is converted to a low-level voltage (L) by the first inverter 34 and then supplied to one end of the first relay 32. In the energized state, the movable contact of the first relay 32 is switched from one fixed contact side (lower side in FIG. 4) to the other fixed contact side (upper side in FIG. 4). At this time, since the movable contact of the second relay 33 remains unchanged, the power supply terminal 40, the movable contact of the first relay 32, the motor 31, the movable contact of the second relay 33, the current value detection resistor 36 , A current path is formed to reach the ground point, and current flows through the motor 31 to open a movable mechanism, for example, a window.

Subsequently, when the window is closed in a state where the movable mechanism, for example, the window is not moving, the window closing operation switch 39 is pressed, and only the output of the close (CLOSE) terminal of the microprocessor unit 38 is output. Low level voltage (L) to high level voltage (H)
Switch to. In this case, the high level voltage (H) is
After being converted to a low level voltage (L) by the second inverter 35, the voltage is supplied to one end of the second relay 33, so that the second relay 33 is energized and the second relay 33 is movable. The contact is switched from one fixed contact side (lower side in FIG. 4) to the other fixed contact side (upper side in FIG. 4). Also at this time, the movable contact of the first relay 32 remains switched to the one fixed contact (lower side in FIG. 4) as before, so that the power supply terminal 40 and the movable contact of the second relay 33 are switched. ,
A current path is formed through the motor 31, the movable contact of the first relay 32, and the ground via the current value detection resistor 36, and a current flows in the motor 31 in a direction opposite to that in the previous case. The window is to be closed.

When the motor 31 is driven, the current flowing through the motor 31 also flows through the current value detection resistor 36. Therefore, if the terminal voltage of the current value detection resistor 36 is detected by the differential amplifier 37, the output of the differential amplifier 37 The current value flowing through the motor 31 is obtained from the voltage. The output voltage of the differential amplifier 37 is supplied to the microprocessor unit 38, and the current measurement / comparison device built in the microprocessor unit 38 measures the current change per unit time of the motor 31 from the output voltage. Then, the measured current change amount is compared with a preset value preset in the current measurement / comparison device. When the current value of the motor suddenly increases due to a movable mechanism, for example, an object being caught in the window or reaching the window movement limit position, the current change is measured by the current measurement / comparison device. It is detected that the quantity exceeds the preset value, and a detection output is sent. This detection output is supplied to a motor drive control device also built in the microprocessor unit 38,
The motor drive control device having received the detection output changes the output of the open (OPEN) terminal or the output of the closed (CLOSE) terminal of the microprocessor unit 38 to a high level (H).
Is switched to the low level (L), the motor 31
To stop the movement of the movable mechanism, for example, the window, and in some cases, by inverting the level of the output voltage of the open (OPEN) terminal and the level of the output voltage of the closed (CLOSE) terminal, respectively. The rotation of the motor 31 is reversed so that the movable mechanism, for example, the window is moved in the reverse direction.

FIG. 5 is a characteristic diagram showing operating characteristics of the motor driving device having the known safety function. FIG. 5A shows a change state of a current flowing through the motor 31.
(B) shows a change state of the lock current when the drive voltage of the motor 31 fluctuates.

5A and 5B, the vertical axis represents the motor current, and the horizontal axis represents time.

[0013] As shown in FIG.
Current flowing to the movable mechanism, for example, during the time t ₀ is the start timing of the movement of the window up to the time t _1, but the current value is large inrush current flows is temporarily increased, the time t ₁ later Then, the rotation of the motor 31 is in a stable state, and a substantially constant normal current flows. Then, the time t _2, the movable mechanism, for example, or Tsu sandwiched an object in the window, when the rotation of the motor 31 comes to be inhibited or reaches the window of the moving limit position, the unit time Δt (t ₂ ~t ₃₎ , A lock current that increases in the current flows. Here, the voltage V
b is a voltage directly supplied from the car battery, and the voltage value may fluctuate slightly due to an external influence, or the voltage value may change with time due to long-time use, and may be lower than the initial value.

In this case, as shown in FIG.
The increasing state of the lock current varies depending on the driving voltage of the motor 31, that is, the voltage Vb supplied to the power supply terminal 40. The higher the driving voltage Vb, the steeper the increase curve.

FIG. 6 is a flowchart showing the operation of the motor drive device having the known safety function. The operation of the motor drive device having the known safety function described above is summarized. Things.

The operation of the motor drive device having a known safety function will be described again with reference to FIG. However, in this flow, an example of the operation when the window is opened as the movement of the movable mechanism will be described.

First, in step S21, the release operation switch 39 is pressed, and the microprocessor unit 38 sends out a high level (H) output voltage to the open (OPEN) terminal. Subsequently, in step S22, the first relay 32 is energized by the high-level (H) output voltage sent from the microprocessor unit 38, and current flows through the motor 31. At this time, the window starts moving. Next, in step S23, the microprocessor unit 38 measures the terminal voltage of the current value detection resistor 36 detected by the differential amplifier 37, and
The current i ₀ flowing through is read. Subsequently, step S24
In the above, when the microprocessor unit 38 reads the current i ₀ , the timer is started. Subsequently, in step S25, the microprocessor unit 3
8 determines whether or not a unit time Δt has elapsed since the start of the timer. Then, if the unit time Δt has passed, the process proceeds to the next step S26, and if the unit time Δt has not passed, the same step S25 is repeated.

Next, at step S26, the microprocessor unit 38 measures the terminal voltage of the current value detection resistor 36 detected by the differential amplifier 37 again, and
Read the current i ₁ flowing to. Next, step S27
, The microprocessor unit 38 obtains the difference between the two currents i ₀ and i ₁ read, that is, the current change amount Δi (i ₁ −i ₀ ) per unit time Δt.
Followed in step S28, the microprocessor unit 38 is compared with the current change amount .DELTA.i and preset value .DELTA.i _s. If Δi _s > Δi, the process returns to the previous step S23, and the operations after step S23 are executed again. If Δi _s ≦ Δi, the next step S29 is performed.
Move to Finally, in step S29, the microprocessor unit 38 is released (OP
The high level (H) output voltage of the EN) terminal or the closed (CLOSE) terminal is converted to the low level (L), and the energized first relay 32 or the second relay 33 is stopped. Then, the current flowing through the motor 31 is cut off. At this time, the window stops moving. Also,
In this step S29, in some cases, the microprocessor unit 38 is released (OPE
N) The level of the output voltage of the terminal and the level of the output voltage of the closed (CLOSE) terminal are respectively inverted, and the energized and deenergized states of the first relay 32 and the second relay 33 are reversed, and the current flows through the motor 31. Reverse the current direction. At this time, the window moves in the opposite direction from the previous moving direction.

[0019]

As shown in FIG. 5 (b), the unit time .DELTA.t for detecting the current change .DELTA.i is constant in the motor drive device having the known safety function. When the drive voltage Vb of the motor 31 fluctuates, the current variation Δi per unit time Δt fluctuates considerably.

For this reason, in a motor drive device having a known safety function, a current change amount Δi per unit time Δt can be detected for all drive voltages Vb within a fluctuation range. as preset value .DELTA.i _s, it is immobilized by selecting the minimum unit value corresponding to the current change amount .DELTA.i _min per time Δt when the driving voltage Vb _min. However, if you choose this preset value .DELTA.i _s, when the maximum drive voltage Vb _max or near the driving voltage Vb, the motor torque is increased when tucked an object to the movable mechanism, at that time Since the motor load becomes too heavy, there is a problem that the sandwiched object is damaged, and particularly when the object is a part of the body, a serious injury is caused.

An object of the present invention is to eliminate such a problem, and an object of the present invention is to provide a motor drive having a safety function in which the motor load at the time of pinching is kept constant irrespective of the fluctuation of the drive voltage of the motor. It is to provide a device.

[0022]

In order to achieve the above object, the present invention provides a motor for moving a movable mechanism, a motor drive control device for controlling rotation, stop and rotation direction of the motor, A current measurement / comparison device that measures a current change amount per unit time and compares the current change amount with a preset value, and detects the current change amount exceeding the preset value by the current measurement / comparison device. A voltage measurement device that measures a motor drive voltage in a motor drive circuit having a safety function of stopping rotation of the motor and / or reversing the rotation direction via the motor drive control device when the voltage measurement is performed. A voltage response time setting device for changing the length of the unit time according to the drive voltage value measured by the device.

[0023]

According to the above means, a voltage measuring device for measuring a motor driving voltage, and a motor current change amount is detected from a drive voltage value measured by the voltage measuring device, and a unit time of a motor is measured based on the current change amount. By providing a voltage response time setting device that changes the length, when the drive voltage is lower than the normal voltage value, the length of the unit time is set to be longer according to the voltage value, When the drive voltage is higher than the normal voltage value, the length of the unit time is set to be shorter according to the voltage value.

As described above, by changing the setting of the length of the unit time according to the drive voltage value of the motor, the amount of change in current flowing through the motor per unit time does not depend on the drive voltage value. , The motor torque and the motor load when the object is detected are kept constant, regardless of the fluctuation of the drive voltage value, and the object that is sandwiched is damaged, This eliminates the fear that serious injuries will occur on the part of the body that is pinched.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a circuit diagram showing the configuration of an embodiment of a motor drive circuit having a safety function according to the present invention.

In FIG. 1, a motor 1 is a DC motor, both ends of which are connected to movable contacts of a first relay 2 and a second relay 3, and a first relay 2 and / or a second relay 3. By switching the movable contact, current flows in the motor 1 in one direction or the opposite direction, or the motor 1
The connection of the current is stopped such that the flow of current stops.
The current of the motor 1 flows to the ground through the current value detecting resistor 6 connected in series to the motor 1. The first relay 2 and the second relay 3 are driven by a microprocessor unit (MPU) 8 supplied via a first inverter 4 and a second inverter 5, respectively, that is, the microprocessor unit 8 Energization and non-energization are controlled according to the output levels of the open (OPEN) and closed (CLOSE) terminals. Both ends of the current value detection resistor 6 are connected to two input terminals of the differential amplifier 7, and the terminal voltage is detected by the differential amplifier 7 and supplied to the microprocessor unit 8. The first voltage dividing resistor 11 and the second voltage dividing resistor 12 are connected between the power supply terminal 10 and the ground point,
The divided output of the power supply voltage (drive voltage) Vb obtained at the connection point between the voltage dividing resistor 11 and the second voltage dividing resistor 12 is supplied to the microprocessor unit 8. The switch 9 is for moving the movable mechanism, is provided for each moving direction of the movable mechanism, and is connected to the microprocessor unit 8.

Although not shown in FIG. 1, the microprocessor unit 8 includes a motor drive control device for controlling the rotation and stop of the motor 1 and the rotation direction of the motor 1, and a unit for flowing the motor 1. A current change amount per time is measured, and the measured current change amount is constantly compared with a preset preset value.When the current change amount exceeds the preset value, a detection output is output to the motor driving device. , A voltage measuring device for measuring the driving voltage Vb of the motor 1, and a voltage for changing the length of the unit time corresponding to the magnitude of the driving voltage Vb measured by the voltage measuring device It has a response time setting device. In this case, the microprocessor unit 8 internally performs data processing digitally, and analog data such as input voltage is digitally converted, and then required processing is performed. Further, although not shown in FIG. 1, the motor 1 is configured to move a movable mechanism such as a window, a sunroof, and a seat of an automobile when the motor 1 is rotationally driven.

The motor driving device having the safety function according to the above configuration operates as follows. However, in the present embodiment, the description will be made assuming that the movable mechanism that is moved by the rotation of the motor 1 is a window.

First, the operation when it is not necessary to open and close the window is the same as the operation of the motor drive device having the known safety function described above, and the microprocessor unit 8 is opened (OPEN). And closure (CL
The output of the (OSE) terminal is set to a low level voltage (L). This low-level voltage (L) is converted to a high-level voltage (H) by the first inverter 4 and the second inverter 5, and the converted high-level voltage (H) is converted to the first relay 2 and the second relay 2.
Is supplied to one end of the relay 3. At this time, since the high level voltage (H) is constantly supplied to the other ends of the first relay 2 and the second relay 3, the first relay 2 and the second
Are not energized, and their movable contacts are switched to one fixed contact side (the lower side in FIG. 1).
No current flows through the motor 1. Therefore, the window does not move at all.

Next, the operation when the window is opened is as follows.
This is the same as the operation of the motor drive device having the known safety function described above, except that only the output of the open (OPEN) terminal of the microprocessor unit 8 is changed from the low level voltage (L) to the high level voltage (H). Switch. This high level voltage (H) is converted to a low level voltage (L) by the first inverter 4 and then supplied to one end of the first relay 2, so that the first relay 2 is turned on. Become the first
The movable contact of the relay 2 is switched from one fixed contact side (lower side in FIG. 1) to the other fixed contact side (upper side in FIG. 1). At this time, since the movable contact of the second relay 3 is at the original switching position, the power terminal 10, the movable contact of the first relay 2, the motor 1, the movable contact of the second relay 3, and the current value detection resistor A current path is formed from the lower side of FIG. 1 to the upper side of FIG.

Subsequently, when the window is not moving, the operation for closing the window is the same as the above-described operation of the motor driving device having the known safety function. 8
Only the output of the CLOSE terminal is switched from the low level voltage (L) to the high level voltage (H). This high-level voltage (H) is converted to a low-level voltage (L) by the second inverter 35 and then supplied to one end of the second relay 33, so that the second relay 33 is turned on. Thus, the movable contact of the second relay 33 is switched from one fixed contact (lower side in FIG. 4) to the other fixed contact (upper side in FIG. 4). Also at this time, since the movable contact of the first relay 32 is still switched to one fixed contact (lower side in FIG. 4), the power supply terminal 40 and the second
Movable contact of the relay 33, the motor 31, the first relay 3
A current path is formed through the movable contact 2 and the current value detection resistor 36 to the ground point, and a current flows in the motor 31 in the opposite direction to the previous case, so that the movable mechanism, for example, the window is closed. Operate.

Next, when the motor 1 is driven and the window is moving in a certain direction, some object is caught in the window or the window reaches the movement limit position, and a lock current flows through the motor 1. The operation at that time will be described.

Also in the present embodiment, the current flowing through the motor 1 when the motor 1 is driven flows through the current value detection resistor 6 when the motor 1 is driven. If the terminal voltage of the value detection resistor 6 is detected by the differential amplifier 7, the value of the current flowing through the motor 1 is obtained based on the output voltage of the differential amplifier 7. The output voltage is supplied to a measurement comparison device and is first converted to a digital output voltage. In this case, the current measurement / comparison device includes a built-in timer circuit that times up every unit time Δt, and when the digital output voltage is input, the digital output voltage is activated when the timer circuit is activated and the time is up. Is measured, that is, the motor 1
Is measured per unit time Δt, and the measured current change Δi is compared with a preset value preset in the current measurement comparison device. As in the case of the above-described motor drive device having a safety function, the current measurement / comparison device has a problem in that the object is caught in the window or the window reaches its movement limit position, and the motor 1 When the lock current starts flowing and the current value suddenly increases, it is detected that the current change amount has exceeded the preset value, and a detection output is transmitted. This detection output is also supplied to a motor drive control device built in the microprocessor unit 8, and the motor drive control device receiving the detection output outputs or closes (CLOSE) the open (OPEN) terminal of the microprocessor unit 8. By switching the output of the terminal from a high level (H) to a low level (L), the rotation of the motor 1 is stopped and the movement of the window is stopped, and in some cases, the output of the open (OPEN) terminal By inverting the level of the output voltage at the CLOSE terminal and the level of the output voltage at the CLOSE terminal, the rotation of the motor 1 is inverted, and the window is moved in the opposite direction.

In this embodiment, the motor 1
Is supplied to a first voltage dividing resistor 11 and a second voltage dividing resistor 12,
The voltage at the connection point between the first and second voltage-dividing resistors 11 and 12 is supplied to a voltage measuring device in the microprocessor unit 8 as a power-supply-dependent voltage representing the fluctuation of the power supply voltage (drive voltage) Vb. Then, the voltage measuring device converts the power supply-dependent voltage into a digital signal and supplies the voltage-dependent voltage to a voltage response time setting device in the microprocessor unit 8. At this time, the voltage response time setting device determines the unit time Δt of the current measurement / comparison device according to the input power supply dependent digital voltage.
, The normal value of the power supply voltage (drive voltage) Vb is, for example, 12 V, and the value when the power supply voltage (drive voltage) Vb fluctuates in an increasing direction from 12 V is, for example, When the power supply voltage (drive voltage) Vb fluctuates in a decreasing direction from 12 V to 16 V, for example, a value of 9 V
Then, the length of the unit time Δt when the power supply voltage (drive voltage) Vb is 12 V is set to the normal length Δt ₁ , and the length of the unit time Δt when the power supply voltage (drive voltage) Vb is 16 V is short Delta] t ₀ from Delta] t ₁ the power supply voltage (drive voltage) Vb
Is longer than Δt ₁ when the unit time Δt is 9 V
Each was changed to be t _2, also the power supply voltage (drive voltage) Vb is, when it is between 16V and 12V,
Alternatively, when the voltage is between 12 V and 9 V, the length of the unit time Δt is changed according to the voltage value.

FIG. 2 is a characteristic diagram showing the operating characteristics of the motor driving apparatus having the safety function according to the present embodiment, and shows the lock that flows through the motor 1 when the power supply voltage (driving voltage) Vb fluctuates. FIG. 2A shows a change state of the current.
Unit time Δt when power supply voltage (drive voltage) Vb fluctuates
Are shown in FIG. 2 (b).

In FIG. 2A, the vertical axis represents the motor current,
The horizontal axis is time, and in FIG. 2B, the vertical axis is unit time Δt, and the horizontal axis is power supply voltage (drive voltage) Vb.

As shown in FIG. 2B, the unit time Δt when the power supply voltage (drive voltage) Vb is a steady value of 12 V
When the power supply voltage (drive voltage) Vb fluctuates in an increasing direction from the steady-state value of 12 V when the length is the normal length Δt ₁ , the length of the unit time Δt is changed according to the fluctuation width.
t ₁ , while the power supply voltage (drive voltage) V
When b fluctuates in a decreasing direction from the steady value of 12 V, the length of the unit time Δt is changed so as to be sequentially longer than Δt ₁ in accordance with the fluctuation width.

As shown in FIG. 2 (a), the increase in the lock current flowing through the motor 1 is larger than the slope when the power supply voltage (drive voltage) Vb is a steady value of 12V.
The power supply voltage (drive voltage) Vb is larger than the steady value 12 V
When the voltage is 6 V, the slope becomes steep, while when the power supply voltage (drive voltage) Vb is 9 V, which is smaller than the steady value of 12 V, the slope becomes gentler. When the slope of the increase of the lock current is steep, for example, when the power supply voltage (drive voltage) Vb is 16 V, the length of the unit time Δt is reduced to Δt ₀ , and the power supply voltage (drive voltage) Vb becomes a steady value. When the slope of the increase of the lock current is steep with respect to the length Δt ₁ of the unit time Δt at 12 V, for example, the power supply voltage (drive voltage) V
The length of the unit time Δt when b is 16 V is set to Δt ₀ shorter than Δt _1. On the other hand, when the slope of the increase of the lock current is gentle, for example, when the power supply voltage (drive voltage) Vb is 9
If caused to change the length of the unit time Delta] t when V so long Delta] t ₂ than the Delta] t _1, power supply voltage irrespective of the fluctuation of (drive voltage) Vb, a current variation value of the motor 1 delta
The detection level of i, that is, the level of the current fluctuation value Δi at which a comparison output between the current fluctuation value Δi and the preset value is obtained can be kept constant.

As described above, according to the present embodiment, the motor 1
Unit time Δ according to the variation of the power supply voltage (drive voltage) Vb
Since t is changed, the current change amount Δi per unit time Δt does not depend on the power supply voltage (drive voltage) Vb. For this reason, a constant amount of current change in the motor 1 can be detected at all times, so that both the motor torque and the motor load when the object is detected can be kept constant. There is no concern that the enclosed object may be damaged or that a part of the body may be severely injured.

FIG. 3 is a flow chart showing the operation of the motor drive device having the safety function according to the present embodiment. The operation of the motor drive device having the safety function according to the present embodiment described above is now described. It is a summary of.

The operation of the motor driving device having the safety function according to the present embodiment will be described again with reference to FIG. However, also in this flow, a description is given assuming that the movable mechanism is a window, and that this is an operation example when the window is opened.

First, in step S1, the release operation switch 9 is pressed, and the microprocessor unit 8 sends a high level (H) output voltage to the open (OPEN) terminal. Subsequently, in step S2, the first relay 2 is energized by the high-level (H) output voltage sent from the microprocessor unit 8, and current flows through the motor 1. At this time, the window starts moving in the opening direction. Next, in step S3, the current measuring / comparing device in the microprocessor unit 8 measures the terminal voltage of the current value detecting resistor 6 detected by the differential amplifier 7, and
The current i ₀ flowing through is read. Subsequently, in step S4, the voltage measuring device of the microprocessor unit 8 sets the voltage at the connection point of the first and second voltage-dividing resistors 11 and 12,
That is, the power supply dependent voltage representing the power supply voltage (drive voltage) Vb is read. Next, in step S5, the voltage response time setting device of the microprocessor unit 8 calculates and sets the unit time Δt in the current measurement and comparison device based on the power supply dependent voltage read by the voltage measurement device. Subsequently, in step S6, the current measurement / comparison device starts the built-in timer circuit. Next, in step S7, the microprocessor unit 8 determines whether or not the set unit time Δt has elapsed since the start of the timer circuit. If it has passed the unit time Δt, the process proceeds to the next step S8, and if it has not passed the unit time Δt, the same step S7 is repeated.

Next, in step S8, the current measuring / comparing device again detects the current value detecting resistor 6 detected by the differential amplifier 7.
Is measured, and the current i ₁ flowing through the motor ₁ is read. Next, in step S9, the difference between the values of the two currents i ₀ and i ₁ read by the current measurement / comparison device, that is, the current change amount Δi (i ₁ −
i ₀ ). Subsequent step S10, the current measurement compared apparatus performs comparison between the current change amount .DELTA.i and preset value .DELTA.i _s. Then, as a result of the comparison, Δi _s > Δi
If so, the process returns to the previous step S3, and again returns to the step S3.
The operations after 3 are executed, and if Δi _s ≦ Δi, the process proceeds to the next step S11. Finally, in step S11, an open (OPEN) terminal or a closed (CLOSE) signal sent from the microprocessor unit 38.
The high level (H) output voltage of the terminal is converted to the low level (L), the energized first relay 2 or the second relay 3 is stopped, and the current is passed to the motor 1. Cut off the current. At this time, the window stops moving in the opening direction. Also, in step S11,
Optionally, an open (OPEN) terminal and a closed (CLOSE) signal sent from the microprocessor unit 8.
The levels of the output voltages of the terminals are respectively inverted, the energized and deenergized states of the first relay 2 and the second relay 3 are reversed, and the direction of the current flowing through the motor 1 is inverted.
At this time, the window is changed from the movement in the opening direction to the movement in the closing direction.

In the above-described embodiment, an example has been described in which each of the motor drive control device, the current measurement and comparison device, the voltage measurement device, and the voltage response time setting device is incorporated in one microprocessor 8. However, the present invention is not limited to such an example. Even if the respective devices are individually configured, the respective devices are configured to be built in two or more microprocessors. May be present.

Also, an example in which the steady value of the power supply voltage (drive voltage) Vb is 12 V and the fluctuation range of the power supply voltage (drive voltage) Vb is within the range of 9 V and 16 V has been described.
The steady-state value and the fluctuation range of the power supply voltage (drive voltage) Vb in the present invention are not limited to those, and can be changed as appropriate.

Further, in the above-described embodiment, an example in which the current value detecting resistor 6 and the differential amplifier 7 are used as current detecting means for detecting the currents i ₀ and i ₁ flowing through the motor 1, The example in which the first and second voltage dividing resistors 11 and 12 are used as the voltage detecting means for detecting the voltage (drive voltage) Vb has been described, but the current detection and the voltage detecting means in the present invention It is a matter of course that other means may be used without being limited to the configuration.

[0048]

As described above, according to the present invention, the voltage measuring device for measuring the motor driving voltage Vb, and the motor current change Δi from the driving voltage value measured by the voltage measuring device.
And the unit time Δt is determined based on the current change amount Δi.
And a voltage response time setting device for changing the length of the drive voltage Vb. When the drive voltage Vb is lower than the normal voltage value, the unit time Δt is set to be longer according to the voltage value. On the other hand, when the drive voltage Vb is higher than a normal voltage value, the length of the unit time Δt is set to be shorter according to the voltage value.

By changing the setting of the length of the unit time Δt according to the drive voltage value of the motor, the current change amount Δi per unit time Δt flowing through the motor 1 does not depend on the drive voltage value. It is possible to detect a constant amount of current change in the motor 1 at all times, so that both the motor torque and the motor load when an object is detected to be trapped are constant regardless of the drive voltage value fluctuation. Can damage the object between them,
This has the effect of eliminating the fear that serious injuries will occur in the part of the body that is pinched.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration of an embodiment of a motor driving device having a safety function according to the present invention.

FIG. 2 is a characteristic diagram showing operating characteristics of a motor drive device having a safety function according to the embodiment shown in FIG.

FIG. 3 is a flowchart showing the operation process of a motor drive device having a safety function according to the embodiment shown in FIG. 1;

FIG. 4 is a circuit diagram showing a schematic configuration of an example of a motor drive device having a known safety function.

FIG. 5 is a characteristic diagram showing operating characteristics of a motor drive device having a known safety function.

FIG. 6 is a flowchart showing an operation process of a motor drive device having a known safety function.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 DC motor 2 1st relay 3 2nd relay 4 1st inverter 5 2nd inverter 6 Current value detection resistance 7 Differential amplifier 8 Microprocessor unit (MPU) 9 Switch 10 Power supply terminal 11 1st voltage division Resistance 12 Second voltage dividing resistance

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yukio Miura 3-1-23 Nakazato, Furukawa-shi, Miyagi 206 Forbe Nakazato 206 (56) References JP-A-6-10561 (JP, A) Japanese Utility Model Showa Sho 62-203392 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) E05F 15/00-15/20

Claims (4)

(57) [Claims] 1. A motor for moving a movable mechanism, a motor drive control device for controlling rotation, stop and rotation direction of the motor, and a current change amount per unit time of the motor is measured. A current measurement / comparison device for comparing the current value with a preset value, and when the current change amount exceeding the preset value is detected by the current measurement / comparison device, the rotation of the motor is controlled via the motor drive control device. A motor driving device having a safety function of stopping and / or reversing the rotation direction, comprising: a voltage measuring device for measuring a motor driving voltage; and the length of the unit time according to the driving voltage value measured by the voltage measuring device. And a voltage response time setting device for changing the voltage of the motor. 2. The motor according to claim 1, wherein the current of the motor is measured by a current value detecting resistor connected in series to the motor and a differential circuit for inputting a terminal voltage of the current value detecting resistor. A motor drive device provided with a safety function according to item 1. 3. The apparatus according to claim 1, wherein the motor drive control device, the current measurement / comparison device, the voltage measurement device, and the voltage response time setting device are incorporated in one microprocessor unit. A motor drive device having the described safety function. 4. The motor drive device with a safety function according to claim 1, wherein the movable mechanism is at least one of a power window, a sunroof, and a power seat of each automobile.