JPH03215117A - Motor overload protection method and overload protection device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention detects an overload state of a motor and stops the motor, thereby limiting the range of movement of a movable member and preventing damage caused by overcurrent. The present invention relates to a motor overload protection method and overload protection device that protects the motor from overheating, damage, etc.

[Conventional technology]

For example, in automobiles and the like, a configuration in which movable members such as parts, power windows, and wing mirrors are moved by controlling the drive of a motor is widely known.

In such a configuration, the drive control of the motor is performed, for example, by operating a manual switch consisting of an automatic double-wheel type switching switch, etc., and the movable member is moved in an arbitrary direction depending on the operating direction of the manual switch. .

In such a configuration, the range of movement of the i-IJ moving member is usually limited by various means, and by stopping the motor at the movement limit position, excessive movement of the moving member is prevented, Protects the motor from overcurrent caused by overload.

As a method of limiting the movement range of a movable member, for example,
A configuration using riminotosui-nochi is generally known. In such a configuration, Rimi. . When the motor moves the movable member to the limit position and the limit switch 7 is activated, the voltage supply to the motor is cut off.
The motor is stopped.

In addition, as another method, for example, the movement range of the movable member is forcibly blocked by a stop or pad provided on a fixed member, etc., and a current suppressing element such as a control circuit or a POSISTOR directly connected to the motor is used. , a configuration is known in which an overcurrent that occurs when the motor is in a locked state is detected, and the motor is stopped after the overcurrent is detected.

[Problem that the invention attempts to solve]

However, in a configuration in which a limit switch and a limit switch are provided, the limit switch is provided in each direction of movement of the movable member, so 2a of limit switches, electric wiring (harness), etc. are each required for one movable member. . Therefore, the number of parts increases and the configuration inevitably becomes complicated.

Limit switches that limit the range of movement of movable members such as arrows are required to have a large rated current. Therefore, there is a possibility that the limit switch cI body becomes expensive.

Additionally, in a configuration with a limit switch and a toswitch, a place is required to attach the minoto suinochi. However, in seating posture control devices, power windows, power mirrors, etc.
Since the movable member is usually installed using a relatively narrow space, the space for installing the limit switch cannot be set at 1.0 cm.

On the other hand, in a configuration in which an overcurrent in a motor overload state is detected by a control circuit, a current suppression element, etc., and upon detection of overcurrent, the motor is stopped and the movement range of the movable member is limited, the movement of the movable member is It is necessary to forcibly prevent this and restrain the motor. However, depending on the characteristics of the control circuit, voltage suppressing element, etc., it may take several tens of seconds from when the motor is restrained to when the motor is stopped. In other words, the stopper and the frame of the movable member are required to have sufficient mechanical strength to withstand the torque of the restrained motor. It is unavoidable that the area around the attachment point of the moving member will become larger.

The controller circuit for detecting overcurrent in the motor is formed from, for example, human capacitance transistors, field effect transistors (FETs), etc., so the configuration becomes complicated. At the same time, it tends to be expensive.

Further, since a current suppressing element is required to have a large capacity, it is difficult to obtain it and it is inevitable that it will be expensive.

This invention aims to reduce the size of the area around the attachment point of the movable member, and also provides an inexpensive overload-proof motor with a simplified configuration.
f protection method and overload protection device.

"Means for Solving the Problem" In order to achieve this object, the motor overload of the present invention
::According to the iho1jψ method, overcurrent tl in series with the motor
The ε detection resistor detects overcurrent, and when it is determined that the motor is overloaded from the detection of overcurrent, the switching means is activated to switch the breaker means and switch the breaker means to the motor, regardless of the operation of the manual switch. voltage supply is cut off.

Then, after a predetermined time delay after the switching means stops operating, the breaker means is automatically returned to its initial state, and voltage is supplied to the motor again.

Here, it is preferable that an alarm be issued at the same time as the voltage supply to the motor is cut off as the breaker means is switched.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

As shown in FIG. 1, a motor overload protection device 10 according to the present invention includes a power supply 12 and an old motor. M2, and is configured to protect each motor from overcurrent generated when the motor is overloaded.

For example, an automobile battery is used as the power source 12, and the positive pole of the battery is connected to the connection terminal 14 of the overload protection device 10, and the negative pole is connected to the connection terminal 16. Moreover, the motor Ml. A DC gear 1 motor is usually used as M2, and each motor has, for example, 4
It is attached to the neck as a driving arm for driving members (not shown) such as a sitting posture control device and various mirrors. And the old motor. M2
For example, overload A::I protection 1, ψ device connection terminal 1
8.20 and is driven by voltage supply from Baddeley (power supply) 12.

Here, drive control of the motor MI=M2 is performed, for example, by a manual switch 22, 24 interposed between the overload protection device 10 and the motor old or motor M2. The manual switches 22 and 24 can be, for example, an automatic return type seesaw type switch with a νl termination at the neutral position, and can arbitrarily change the driving direction of the motor according to the direction in which the switch is operated. It is configured to be selectable.

According to the manual switch 22.24 having such a configuration, when the manual switch is not operated, the motor MI. M
Since the two winding terminals are short-circuited, regenerative braking is applied to each motor, and each motor is held in a stopped state under regenerative braking. Therefore, Mo Yuzuki. The stopping accuracy of M2 is improved, and a holding force is applied to each motor to prevent the movable member from moving unexpectedly when the motor is stopped.

As shown in FIG. 1, the motor overload protection device IO of the present invention includes an overcurrent detection resistor Ro and a switching means 2.
6 and a breaker means 28.

As the overcurrent detection resistor RO, for example, a small rated value (
A resistor of several Ω) is normally used, and the overcurrent detection resistor is connected to the motor Ml. Connected in series with M2.

For example, when at least one of the manual switches 22 and 24 is operated in any direction, current flows through the overcurrent detection resistor Ro! When 0 flows, a voltage loXRo proportional to the current 1o is generated at the terminal of the detection resistor Ro. For example, motor M1. When M2 becomes overloaded and the torque of the motor increases, the current 1o increases due to the characteristics of the motor, and the voltage at the terminal of the overcurrent detection resistor Ro increases as the current increases by {t. That is, by constantly monitoring the voltage value at the terminal of the overcurrent detection resistor Ro and comparing it with a predetermined value, an overcurrent, that is, an overload 4:t state of the old motor M2 can be detected.

The voltage value of the overcurrent detection resistor Ro terminal is compared with, for example, a preset value set in the switching means 26, and when the voltage value of the detection resistor Ro terminal reaches the set value, the motor old. It is determined that M2 is in an overload condition. For example, a transistor T can be used as the switching means 26, and the hess-to-emitter voltage VBE of the transistor TRI is set as a reference value for overcurrent detection, and the overcurrent detection resistor 1? It is compared with the voltage value of the o terminal. transistor TR
The setting value VBE of I (switching means 26) is the same as that of the old motor. Overcurrent detection resistance R during steady driving of M2
When the voltage value of the detection resistor Ro reaches the set value VBE, the transistor T
The RI is configured to go from a deactivated (off) state to an activated (on) state.

The breaker means 28 is connected to turn on and off the transistor TRI of the switching means 26. As the breaker means 28, for example, an electromagnetic relay that opens and closes the relay contacts 30 by passing a current through a coil can be used. The relay contacts 30 of the relay RLI (breaker means 28) include, for example, a movable contact 30a, a fixed contact 30b. 30c, and the movable contact 3
0a is the overcurrent detection resistor Ro size 1, fixed contact 30b
The motor is old. They are respectively connected to the connection terminal 18 sites to which M2 is connected. Relay R1,1 is a transistor T
Energization and deenergization are controlled in conjunction with the on and off of the RI,
When the relay is de-energized, the movable contact 30a is normally brought into contact with the fixed contact 30b, allowing voltage to be supplied to the motor M2. Further, as the relay RLI is energized, the movable contact 30a changes from the fixed contact 30b to the fixed contact 30.
c, and the voltage supply to the motors Ml and M2 is cut off.

Here, the alarm display means 32 is connected to the fixed contact 30c of the relay R1,1, and the motor MI. It is preferable to adopt a configuration that displays the interruption of the voltage supply to M2. As the alarm display means 32, for example,
Electronic buzzer can be used, fixed contact 30 of relay R1,1
The electronic buzzer is configured to sound by switching the movable contact 30a from the fixed contact 30c to the fixed contact 30c.

According to such a configuration, motor M1. When M2 becomes overloaded and relays R1 and 1 are energized, the electronic buzzer 32 sounds simultaneously with cutting off the voltage supply to each motor, making it easy for the operator to remove the overloaded motors. can be recognized.

By the way, relay contact 30 is switched due to energization of relay RL1 due to the occurrence of overcurrent, and the old motor. M2
When the voltage supply to is cut off, the current IO becomes 7 Ω.

In other words, the voltage value at the overcurrent detection resistor RO terminal becomes zero, the voltage value at the detection resistor RO terminal becomes strong, and the transistor TRI
is smaller than the set value VBE.

Therefore, by energizing relay RLI, the motor old. M
Even if the voltage supply to 2 is cut off, the switching of the relay contact 30 will turn off the transistor TRI, which may cause the relay RLI to be energized and deenergized little by little, causing a chattering phenomenon in the relay contact. There is. Therefore, the overload protection device 1O of the present invention includes, for example, a delay circuit 34 including a diode D1, a capacitor C1, and a resistor R1 connected in parallel with the relay RLI.

For example, due to the occurrence of overcurrent, transistor TRI
When turned on, the capacitor C1 is charged via the diode DI at the same time as the relay RLI is energized. Then, when the transistor TRI is turned off by switching the relay contact 30, the relay R is transferred from the capacitor Cl to the relay R.
Charge is discharged to LI via resistor R1. Then,
Due to the discharge of the capacitor C1, the energized state of the relays R1 and 1 is continued, and the switching of the relay contact 30 due to the de-energization of the relay RLI is delayed for a predetermined period of time due to the discharge of the capacitor CI. Therefore, the chattering phenomenon of the relay contacts 30 is prevented, and the relay contacts are protected.

Note that the delay time for deactivating the relay RLI by the delay circuit 34 can be arbitrarily selected by the capacitor CI, the resistor R1, and the deactivating voltage of the relay.

Also, normally, motor M1. At the time of starting M2, a large current momentarily flows as a current 1o, so that the voltage value at the terminal of the overcurrent detection resistor Ro momentarily changes to the voltage value at the terminal of the overcurrent detection resistor Ro.
I becomes larger than the set value VBE. Therefore, in a circuit with such a configuration, the voltage value at the terminal of the overcurrent detection resistor Ro and the set value VBI of the transistor TRI are compared using the time constant of the resistor R2 and the capacitor (:2).
It is configured to be delayed by a predetermined time from the start of M2. Such configuration-C has motor M1. After M2 starts and the current 1o becomes stable, the overcurrent detection resistor Ro
Since the terminal voltage value and the set value VBE of the transistor 1'R1 are compared, malfunction of the transistor 1'R1 can be prevented.

Here, in such an overload protection device IO, if the polarity of the battery is incorrectly connected when replacing the battery 12, for example, the old motor may be damaged. M2 is driven in the direction opposite to the indications of the manual switches 22 and 24, and there is a risk that the transistor TRI may be damaged. Therefore, for example, a diode D2 is arranged in parallel with the transistor TRI and in series with the relay RLI, with its cathode connected to the connection terminal l4 side.

In such a configuration, for example, if the polarity of the battery l2 is reversed, that is, if the battery's positive pole is connected to the connection terminal I6 and its negative pole is connected to the connection terminal 14, the current from the battery's positive pole flows to relay contact 3o via relay RLI and diode D2. At this time, the movable contact 30a is switched from the fixed contact 3ob to the fixed contact 30c by the biasing of the relay RLI, so that the movable contact 30a is switched from the fixed contact 3ob to the fixed contact 30c. The voltage supply to M2 is cut off, and the electronic buzzer 32 sounds. Therefore, motor M1. Malfunction of M2 is prevented, the sound of the electronic buzzer 32 allows the operator to recognize the occurrence of stomach upset, and the transistor TRI is protected.

Note that by providing diode D2, relay RL
The transistor TRI is also protected against a back electromotive force of 1.

The operation of the overload protection device 1o as described above will be explained with reference to the circuit diagram of FIG. 1 as well as the time charts of FIGS. 2 to 4.

For example, when the manual switch 22, 24 is not operated, the movable contact of the manual switch is at the short-circuited end of the neutral point, so that the motor old. The winding terminals of M2 are short-circuited, and each motor is stopped and held under regenerative braking.

For example, as shown in FIG. 2, when the manual switch 22 is turned on by operating it in any direction, the voltage supply from the battery 12 is applied to the motor via the overload protection device 10 and the manual switch l2. is applied to drive the motor M1 in the corresponding direction.

At this time, since the voltage value at the terminal of the overcurrent detection resistor Ro is smaller than the set value VBE of the transistor TRI, as shown in the second line 1, the transistor TRI is maintained in an off state.

After the movable member has been moved to an arbitrary position, when the operating force on the manual switch 22 is released, the movable contact of the manual switch returns to the neutral point where the short-circuited end is located. Then, the winding terminals of the motor M1 are short-circuited through the short-circuited end of the manual switch 22, regenerative braking is applied to the motor M1, and the old motor is stopped under the regenerative braking.

By the way, when the motor old becomes overloaded due to the arrival of the movable member to the movement limit position, etc., the current 1o becomes an overcurrent, and the voltage value at the terminal of the overcurrent detection resistor Ro increases. Then, as shown in FIG. 3, when the voltage value of the overcurrent detection resistor Ro reaches the set value VBE of the transistor TR1, the transistor TRI is turned on, the relay RLI is energized, and the relay contact 30 is switched. It will be done. Then, regardless of the operating state of the manual switch 22, the voltage supply to the motor M1 is cut off, the old motor is immediately stopped, and the electronic buzzer 32 is sounded to warn the operator of the motor overload condition. Inform. When the operator recognizes an abnormality in the motor by the sound of the electronic buzzer 32 and interrupts the operation of the manual switch 22, the voltage supply from the battery 12 is completely cut off and the delay circuit 3
After a delay time of 4, the relay RLI is deenergized and the movable relay contact 30a is returned to the fixed contact 30b.

For example, when the motor is overloaded and the operator continues to operate the manual switch 22 even after the delay time for deactivating the relay RLI by the delay circuit 34 has elapsed, as shown in FIG. , transistor 1'RI
ON, OFF, stuck ′, relay old, energization and de-energization of ■ are repeated. Therefore, the electronic buzzer 32 sounds intermittently until the operation of the manual switch 22 is interrupted.
Keep the operator informed of any abnormalities in the old motor. Therefore, the operator will not accidentally miss the sound of the electronic buzzer 32.
It is possible to make the operator reliably aware of abnormalities in the old motor.

Incidentally, by operating the manual switch 24, the motor M2 is similarly driven, and the motor M2 is protected from overcurrent by the operation of the pre-overload protection device IO, similar to the above.

As described above, according to the motor overload protection method of the present invention, the motor Ml. Overcurrent detection resistor Ro in series with M2
When an overcurrent is detected and an overload condition of the motor is detected, the transistor TI? By turning on relay R1
, l are energized, and the voltage supply to each motor is cut off.

Then, after a delay of a predetermined time after transistor TRI is turned off, relay RLI is automatically deenergized, and motor Ml. The voltage is being supplied to M2 again.

In other words, by forcibly blocking the movement of movable members using a stopper, etc., and removing the old motor. When M2 is restrained and placed in an overloaded state, the motor is immediately stopped, so the movement range of the driving member can be reliably limited without providing a rim switch, electrical wiring, etc. Therefore, the number of parts can be reduced, and the mounting space for the limit switch is no longer required, and the area around the mounting location of the movable member can be made smaller.

Moreover, after the transistor TRI is turned off,
After a predetermined time delay, relay 1? Since LI is deenergized, relay RLI, ie motor Ml. Malfunction of M2 and chattering phenomenon of relay contact 30
・Can be prevented in minutes.

And the old motor. Almost at the same time as the overcurrent caused by the overload condition of M2 is detected, the voltage supply to the motor is cut off, so even if the movement of the movable member is forcibly prevented by a stopper, etc., the large torque when the motor is locked is , does not have much effect on stonova, etc. In other words, at the movement limit position, the stop bar that forcibly blocks the movable member, the frame of the moving member that is locked to the stop bar, etc.
Since it can be formed without requiring reinforcement, the area around the attachment point of the driving member can be made smaller in this respect as well.

Furthermore, as the relay contact 30 of relay RLI is switched, motor M1. If the electronic buzzer 32 is configured to sound at the same time as the voltage supply to the motor M2 is cut off, the operator of the manual switch 22.24 can control the motor M1. An overload condition of M2 or the arrival of the movable member at the movement limit position can be easily recognized.

Also, when the polarity of the telly 12 is mistakenly connected in the opposite direction, the relay RLI is energized and the motor Ml. M
If the configuration is such that the voltage supply to the transistor TRI is cut off, malfunction of the motor and protection of the transistor TRI, etc. can be reliably performed.

According to the motor overload protection device 10 of the present invention, the above-mentioned motor overload protection method can be successfully carried out despite the simple configuration, and the motor overload protection device 10 can be protected from overcurrent. M2 can be protected and the movement range of the movable member can be reliably limited.

Further, according to the overload protection device IO of the present invention, since it does not have an expensive load control circuit, voltage suppressing element, etc., it can be formed at low cost, and by appropriately selecting the relay contact capacity, a circuit through which a large current flows can be formed. It can also be used as a protection device without complicating the configuration.

In the embodiment, two motors Ml. A configuration in which M2 is protected by the same overload protection device 10 is illustrated and embodied in FIG. In this way, when protecting multiple motors with the same overload protection device 10,
When the current generated by each motor during restraint is approximately the same, it can be particularly effectively used, for example, when protecting the motors of seat slide devices, reclining devices, etc. of seating posture control devices. However, in this case, when multiple motors are used simultaneously, the current IO flowing in the overload protection device increases, and the voltage value at the overcurrent detection resistor RO terminal increases, so the overload protection device 10 is activated. However, the voltage supply to all motors is cut off.

Therefore, movement of the motors can be prevented, and each motor can be individually maintained. It goes without saying that the overload protection device IO may be provided in a circuit that individually protects one motor without being limited to a plurality of motors.

Further, in the embodiment, the alarm display means 32 is embodied as an electronic buzzer, but the alarm display means 32 is embodied as an electronic buzzer. M2
Since any device that can easily recognize the interruption of voltage supply to the device is sufficient, the present invention is not limited to an electronic buzzer, and may be configured to light up a display lamp, for example.

Further, the switching means 26 can be set in advance to a set value that can be compared with the voltage at the terminal of the overcurrent detection resistor Ro, and it is sufficient that the switching means 26 can switch between on and off states according to the comparison result. For example, the structure is not limited to 1, and may be configured using a thyristor or the like.

Note that the motor overload protection method of the present invention is not limited to automatic applications, but can be widely applied as a protection method for motors disposed as drive sources for movable members.

The above-mentioned embodiments are for illustrating the present invention, and are not intended to limit the present invention in any way, and any modifications, modifications, etc. made within the technical scope of the present invention are also included in the present invention. Needless to say.

〔Effect of the invention〕

As described above, according to the motor overload protection method according to the present invention, when an overloaded state is detected, the motor is immediately stopped, so the movement range of the movable member is ensured without the need for limit switches, harnesses, etc. can be limited to Therefore, the number of parts can be reduced, and the mounting space for the limit switch is no longer required, and the area around the mounting location of the movable member can be reduced in size by 1 degree.

Since the voltage supply to the motor is cut off almost at the same time when an overload condition is detected from an overcurrent, the large torque at the time of motor lock is not so much applied to the stonova or the like. Therefore, there is no need to reinforce the steering bar, the frame of the movable member, etc., and in this respect as well, the area around the attachment point of the driving member can be made smaller.

Historically, since the breaker means is returned to its initial state after a predetermined time delay after the switching means is deactivated, malfunctions of the breaker means, that is, the motor, can be prevented within 1 minute.

In addition, if the configuration is such that an alarm is issued at the same time as the voltage supply to the motor is cut off due to switching of the breaker means, the operator of the manual switch can alert the operator of the motor's overload condition or movement to the limit position. The arrival of parts, etc. can be easily recognized.

If the breaker means is switched to cut off the voltage supply to the motor when the polarity of the power supply is reversed, malfunction of the motor and switching means etc. can be reliably protected.

Historically, according to the motor overload protection device of the present invention, despite the simple configuration, the above-mentioned motor overload protection method can be properly performed, and the motor can be protected from overcurrent and , the range of movement of the movable member can be reliably limited.

Further, according to the i5-color load protection device of the present invention, since it does not have an expensive control circuit, voltage suppressing element, etc., it can be formed at low cost, and by appropriately selecting the rated capacity of the breaker means, large current It can also be fully utilized as a protection device for a flowing circuit without complicating the configuration.

[Brief explanation of drawings]

FIG. 1 is a schematic circuit diagram of a motor overload protection device according to the present invention, and FIGS. 2, 3, and 4 are time charts of a motor overload protection method according to the present invention. . 10: Motor overload protection device, 12: Power supply (battery), 22.24: Manual switch, 26:
Switching means (transistor TRI'), 28
: Break force means (relay RLI), 32: Alarm display means (electronic buzzer), 34: Delay circuit, old. M2: Motor, RO: Overcurrent detection resistor.

Claims (5)

[Claims] (1) Overcurrent is detected by an overcurrent detection resistor connected in series with the motor, and when the overcurrent is determined to be overloaded, the switching device is activated regardless of manual switch operation. is activated, switches the breaker means, cuts off the voltage supply to the motor, and automatically returns the breaker means to the initial state after a predetermined time delay after the switching means stops operating, and then switches the breaker means to the motor. A motor overload protection method that re-energizes the voltage supply. (2) The motor overload protection method according to claim 1, wherein at the same time as the voltage supply to the motor is cut off due to switching of the breaker means, an alarm is issued to inform that the motor has stopped. (3) The motor overload protection method according to claim 1 or 2, wherein the connecting direction of the power source is detected, and when the polarity of the power source is connected in the opposite direction, the breaker means is switched to cut off the voltage supply to the motor. . (4) An overcurrent detection resistor is connected in series with the motor to detect overcurrent of the motor, and the voltage value at the terminal of the overcurrent detection resistor is monitored, and when the voltage value reaches a predetermined value, the operation is stopped. a switching means that can be switched from the motor to an operating state; a breaker means that is operably connected to the switching means and supplies or cuts off voltage to the motor in conjunction with the activation and stopping of the switching means; and a breaker that returns to an initial state. a delay circuit that delays the return of the switching means by a predetermined period of time after the switching means stops operating; When the switching means is activated, the breaker means is switched to cut off the voltage supply to the motor, and the breaker means is automatically returned to the initial state after a predetermined time delay after the switching means stops operating, and the breaker means is switched to the motor. Motor overload protection device that re-supplies voltage. (5) The motor overload protection device according to claim 4, further comprising an alarm display means for notifying the motor of stopping at the same time as the voltage supply to the motor is cut off in response to switching of the breaker means.