JP5325441B2 - Motor drive control device for power tool drive - Google Patents

Description

  The present invention relates to a motor drive control device for driving an electric tool for controlling driving of an electric motor for driving an electric tool.

In the electric tool described above, various electric tools are operated by driving the electric motor by turning ON the operation switch.
Further, the electric tool is provided with a lock means for maintaining the operation switch in a predetermined ON state, so that the operation tool can be concentrated while maintaining the operation switch in the predetermined ON state. Yes.
By the way, while the electric tool is in use, the electric tool is sometimes de-energized due to, for example, a power failure or an outlet being disconnected, and the electric tool is temporarily stopped. In this case, if the operation switch is kept in a predetermined ON state, there is a disadvantage that the electric tool starts to move unexpectedly when the power failure is restored or when the outlet is turned on again.

Therefore, when the operation switch is maintained in a predetermined ON state when the power to the electric motor is cut off due to a power failure or disconnection of the outlet, the driving of the electric motor is prevented even if the power is restored. The thing comprised so that it can do is proposed (for example, refer patent document 1, 2).
JP-A-8-33679 (see FIG. 1) JP 2006-518181 A (see FIG. 3)

In Patent Document 1, a main switch that is connected in series to an AC power source and switches between supplying and not supplying power to a microcomputer as a control unit, and an on switch for driving and stopping an electric motor And an off switch.
According to the above configuration, in order to drive the electric tool, the electric motor cannot be driven unless the main switch is turned on and the on switch is turned on. Two switches had to be operated, and the switch operation was troublesome.
In addition, when the main switch is turned on and the on switch is in the OFF state, the electric motor does not operate, but in this state, the power is supplied to the control unit, so the main switch is turned off. During this period, the control unit (microcomputer) may malfunction due to the influence of noise or the like.
Further, when a battery as a DC power source is used instead of the AC power source, for example, the operation is finished with the main switch being ON and the ON switch being OFF, and the electric tool is not removed from the electric tool body. When the battery is stored, the controller (microcomputer) is energized, so that not only the battery discharge proceeds, but the controller (microcomputer) is affected by noise as described above. There was a risk of malfunction.
In Patent Document 2, although only one operation switch is turned on, the switch operation as in Patent Document 1 does not become troublesome, but the operation switch is turned on in the microcomputer as the control unit. When the worker is unaware of the state, the electric motor can be prevented from moving even when connected to an AC power source. That is, since the power supply is always connected to the control unit (microcomputer) regardless of the ON / OFF operation of the operation switch, the control unit (microcomputer) is as described above, as in Patent Document 1. Inconveniences such as battery discharge and battery discharge in the case of using a battery as a DC power supply instead of an AC power supply cannot be solved.

  In view of the above-described situation, the present invention intends to solve a motor drive for driving an electric tool that can reliably eliminate inconveniences such as malfunction of a control unit and battery discharge while improving operability. It is an object to provide a control device.

The present invention relates to an electric motor for driving an electric tool, a power supply unit for supplying electric power to the electric motor, and an operation switch capable of ON-OFF operation for driving the electric motor by electric power from the power supply unit And when the operation switch is in a predetermined ON state and the power from the power supply unit to the electric motor is cut off, the electric motor is driven even if the power from the power supply unit is restored. A motor drive control device for driving an electric tool comprising a control unit having a blocking means for blocking, wherein the operation switch is interposed in a closed loop constituted by the power supply unit and the control unit , The operation switch is composed of a trigger switch configured to be able to operate a set stroke, and the trigger switch controls the number of rotations of the electric motor according to the operation position of the switch. An operation position detection means for detecting the operation position of the trigger switch from the volume position from the volume controller, and the operation position detected by the operation position detection means, Judgment means for judging that the operation switch is in a predetermined ON state is provided .
By interposing the operation switch in the closed loop constituted by the power supply unit and the control unit as described above, power is not supplied from the power supply unit to the control unit when the operation switch is in the OFF state. In the state where electric power is supplied, the electric motor can be driven and stopped immediately by simply turning on and off the operation switch. When the operation switch is in a predetermined ON state when the power from the power supply unit to the electric motor is cut off, even if the power from the power supply unit is restored, the electric motor is blocked by the blocking means of the control unit Will be blocked.

  The position detection means is means for detecting a voltage value of the volume controller that fluctuates according to an operation position of the trigger switch, and it is determined from the detected voltage value that the operation switch is in a predetermined ON state. May be.

  You may provide the locking means for fixing this trigger switch in the operation position which will be the said predetermined ON state of the said trigger switch.

  You may provide the alerting | reporting means for alert | reporting to a worker that the said prevention means is operated in the said control part and the drive of the said electric motor is blocked | prevented. The notifying means here includes means for sounding a buzzer sound or voice message, means for displaying a message on a display screen provided in the power tool body, in addition to means for lighting or blinking the lamp.

  The notification means may be constituted by a light emitting diode that is turned on or blinked by the control unit. In the case of the light emitting diode, since power consumption is less than that of a general lamp or buzzer, the burden on the battery can be reduced particularly when driven by a battery.

By interposing an operation switch in a closed loop composed of a power supply unit and a control unit, power is not supplied from the power supply unit to the control unit when the operation switch is in an OFF state, It is possible to provide a motor drive control device for driving an electric tool that can reliably eliminate inconveniences such as battery discharge.
In addition, the operability can be improved because the electric motor can be driven and stopped immediately by switching the operation switch.
Furthermore, when the power from the power supply unit is cut off and the operation switch is in a predetermined ON state, even if the power from the power supply unit returns, Since the motor is prevented from being driven, the electric motor does not suddenly move without the operator's knowledge, and the product can be made highly reliable.

FIG. 1 is a circuit diagram showing an embodiment of a motor drive control device for driving an electric tool such as an electric drill, a reciprocating saw, or a grinder.
This motor drive control device drives an electric motor 1 by an electric motor 1 for driving an electric tool, a battery 2 constituting a power supply unit for supplying electric power to the electric motor 1, and electric power from the battery 2. Power switch 3 that can be turned on and off, and power from the power supply unit 2 when the switch 3 is in a predetermined ON state and power from the power supply unit 2 to the electric motor 1 is cut off. And a microcomputer 5 as a control unit having a blocking means 4 for blocking the driving of the electric motor 1 even if the motor is restored.

  In a state where the operation switch 3 is interposed in a closed loop constituted by the battery 2 and the microcomputer 5 and the operation switch 3 is not turned on (OFF state), the battery 2 is transferred to the microcomputer 5. Is configured not to be energized.

  As the battery 2, a secondary battery such as a lithium ion battery, a nickel cadmium battery, or a nickel metal hydride battery, or a primary battery such as a manganese dry battery or an alkaline dry battery can be used.

  The operation switch 3 includes a trigger switch configured to be able to operate a set stroke. The trigger switch 3 is provided between the plus side of the battery 2 and the input side of the microcomputer 5, A contact 6 that closes when the pull-in operation of the switch 3 is started, and a volume controller 7 for controlling the number of revolutions of the electric motor 1 according to the operation position of the trigger switch 3 are provided. On the basis of the operation position detection means 8 for detecting the operation position of the trigger switch 3 from the volume position and the operation position detected by the operation position detection means 8, the trigger switch 3 is in a predetermined ON state (lock ON described later). Determination means 9 for determining that the state is). Incidentally, reference numeral 10 shown in FIG. 1 denotes a Zener diode provided in the circuit for stabilizing the voltage.

  The electric motor 1 is driven at a higher speed as the trigger switch 3 approaches the maximum operation position, and the drive speed of the tool provided at the tip of the electric tool can be changed.

The position detecting means 8 is a means for detecting the voltage value of the volume controller 7 that fluctuates in accordance with the operation position of the trigger switch 3, and from the detected voltage value, the operation switch 3 is in a predetermined ON state. It comes to judge that there is.
The volume controller 7 divides the reference voltage into an arbitrary ratio by sliding on the volume 7A composed of a resistor and the volume switch 7A in conjunction with the operation of the trigger switch 3, and the divided voltage is reduced to a micro level. And a movable electrode 7B for outputting to the computer 5.

Specifically, FIG. 2B shows a state where the reference voltage is 5 V and the trigger switch 3 is slightly pulled from the state where the trigger switch 3 is not operated as shown in FIG. . In FIG. 2A, since the contact 6 is in an open state, the power from the battery 2 is not supplied and the reference voltage is 0 V as described above. In FIG. 2B, when the trigger switch 3 is pulled slightly, the contact 6 is immediately closed and the reference voltage rises to 5V. However, since the trigger switch 3 is not pulled so much, it becomes almost 5V, and this voltage is detected by the position detecting means 8 of the microcomputer 5 and the electric motor 1 is slowly driven from the microcomputer 5 based on the detection result. Thus, the PWM control signal is output to the switching element 12 described later.
When the trigger switch 3 is further pulled, the movable electrode 7B slides and the voltage at that time becomes 0V as shown in FIG. This voltage is detected by the position detection means 8 of the microcomputer 5, and a PWM control signal is described later so that the electric motor 1 can be driven quickly from the microcomputer 5 based on the detection result (for example, driven at the maximum speed). Is output to the switching element 12.

  As shown in FIG. 1, a lock means 11 for fixing the trigger switch 3 at the maximum operating position is provided. Therefore, the power tool can be concentrated and used in a state where the trigger switch 3 is locked at the maximum operation position by the lock means 11 (lock ON state). When the power tool is used for a long time in the lock ON state, the power of the battery is greatly consumed, and the power tool may not move during use. If the battery is replaced while forgetting that the lock is ON in such a state, energization to the microcomputer 5 is resumed. However, the maximum operation when the trigger switch 3 is operated to the maximum. The blocking means 4 is configured to be operated at a position, that is, at a position where the predetermined ON state is set, so that the electric motor 1 is not unexpectedly driven.

  When the microcomputer 5 operates the blocking means 4 to block the driving of the electric motor 1, the LED (light emitting diode) 13 (see FIG. 1) provided in the electric tool is blinked. Is provided with an informing means capable of notifying that the driving of the electric motor 1 is blocked. Reference numeral 14 shown in FIG. 1 denotes a driving transistor for driving the LED 13. The LED 13 blinks (may be lit) by ON / OFF control of the driving transistor 14 using an output signal from the microcomputer 5. I try to let them.

  A switching element 12 that can be driven by the microcomputer 5 is provided in the power supply path to the electric motor 1, and the switching element 12 is controlled to be turned on and off based on a command signal from the microcomputer 5. The number of rotations of the electric motor 1 can be controlled. That is, the microcomputer 5 outputs a PWM control signal which is a pulse signal, and the electric motor 1 can be rotated at a high speed by taking a large duty ratio of the pulse signal. It has become.

The drive control of the electric motor 1 by the motor drive control device configured as described above will be described based on the flowchart shown in FIG.
First, it is determined whether power from the battery 2 is supplied to the microcomputer 5 (step S1). If power is supplied, the voltage value of the volume controller 7 is read (step S2), and it is determined whether or not the voltage value is 0V (step S3). That is, when the voltage value is 0V, it is determined that the trigger switch 3 is held at the maximum operating position by the lock unit 11 as described above (the lock is on), and the blocking unit 4 is The electric motor 1 is stopped by operating and blocking the driving of the electric motor 1 (step S4). At the same time, the LED 13 is blinked (step S5). Then, while the LED 13 is blinking, it is determined whether or not the electric power from the battery 2 is supplied to the microcomputer 5 (step S6). If the electric power is supplied, the LED 13 continues to blink and the electric power supply is continued. When stopped, the drive control of the electric motor 1 (control to prevent the drive) is finished. When the power supply is stopped, the trigger switch 3 is returned from the maximum operation position to the operation start position (position where the contact 6 is opened), or the battery 2 is removed, or the battery 2 is exhausted to supply power. It is one of the states where it is no longer possible.

  If the trigger switch 3 is not pulled at the time of the determination in step S3, the voltage is 5V, and it is determined that the trigger switch 3 is not held at the maximum operating position (not in the lock ON state), The electric motor 1 is driven according to the operation position of the trigger switch 3 (step S7). Then, while driving the electric motor 1 according to the operation position of the trigger switch 3, it is determined whether or not the electric power from the battery 2 is supplied to the microcomputer 5 (step S8). Continues to drive the electric motor 1 according to the operation position of the trigger switch 3, and when the power supply is stopped, the drive control of the electric motor 1 is terminated. In addition, when the said electric power supply stops, it is the same as the above-mentioned.

  Although the configuration has been shown in which the trigger switch 3 can be fixed at the maximum operation position by the lock means 11, the configuration is such that the trigger switch 3 can be fixed at a plurality of operation positions other than the maximum position and at a predetermined number of revolutions or more. May be. In this case, the microcomputer is configured to determine that the state maintained at all the fixed operation positions is the lock ON state (predetermined ON state), and the electric motor 1 is in the predetermined ON state. When the supply of power is resumed in a state where the power to is turned off, the drive of the electric motor 1 is stopped as described above. The specific configuration of the trigger switch 3 may be a configuration other than that shown in FIG.

  Moreover, although the case where the rotation speed of the electric motor 1 can be linearly changed according to the operation position of the trigger switch 3 has been shown, for example, a configuration in which the rotation speed can be changed in two stages or three or more stages may be employed. Moreover, the electric motor 1 that rotates only at the set rotational speed may be used.

  In addition, although the notification means for notifying the operator that the driving of the electric motor 1 by the microcomputer 5 is blocked by the blinking of the LED 13 (which may be turned on) is provided, the notification means is sounded by sounding a buzzer or a voice message. It may be configured, and when the electric tool is provided with a display screen, a notification means for displaying that the drive of the electric motor 1 is blocked by a text message or the like may be displayed on the display screen. . The use of the LED 13 is advantageous in terms of power consumption, but other general lamps can also be used. Moreover, depending on the case, it can also implement without providing alerting means, such as LED for alerting | reporting to an operator.

  In addition, the case where the trigger switch 3 is confirmed to be fixed at the maximum operation position by the lock means 11 is shown from the voltage value of the volume controller 7, but the current value from the volume controller 7 and the resistance value of the volume 7A are shown. You may make it confirm from.

  Moreover, although the structure which drives the electric motor 1 using the battery 2 as a power supply part was demonstrated, the electric motor 1 may be driven with a commercial alternating current power supply, and the electric motor 1 is any AC or DC. It may be a configuration for both AC and DC that can be driven.

It is a circuit diagram which shows one Example of the motor drive control apparatus for electric tools. It is explanatory drawing which shows the contact which changes with operation of a trigger switch, and a movement of a volume controller, (a) shows the state immediately before operating a trigger switch, (b) shows a contact by slightly operating a trigger switch. The closed state is shown, and (c) shows the state where the trigger switch is operated to the maximum operating position. It is a flowchart which shows the drive control of a motor drive control apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Electric motor, 2 ... Battery (power supply part), 3 ... Operation switch (trigger switch), 4 ... Blocking means, 5 ... Microcomputer (control part), 6 ... Contact, 7 ... Volume controller, 7A ... Volume, 7B DESCRIPTION OF SYMBOLS ... Movable electrode, 8 ... Operation position detection means, 9 ... Judgment means, 10 ... Zener diode, 11 ... Lock means, 12 ... Switching element, 14 ... Driving transistor,

Claims (5)

An electric motor for driving an electric tool, a power supply unit for supplying electric power to the electric motor, an operation switch capable of ON-OFF operation for driving the electric motor by electric power from the power supply unit, and the operation Blocking means for preventing the driving of the electric motor even when the power from the power source is restored when the switch is in a predetermined ON state and the power from the power source to the electric motor is cut off A motor drive control device for driving an electric tool comprising a control unit comprising:
The operation switch is interposed in a closed loop composed of the power supply unit and the control unit, and the operation switch includes a trigger switch configured to operate a set stroke. An operation position detection unit that includes a volume controller for controlling the number of rotations of the electric motor according to an operation position of the switch, and wherein the blocking unit detects the operation position of the trigger switch from the volume position from the volume controller; And a motor drive control device for driving an electric tool , comprising: a determination unit that determines that the operation switch is in a predetermined ON state based on the operation position detected by the operation position detection unit. . The position detection means is means for detecting a voltage value of the volume controller that fluctuates according to an operation position of the trigger switch, and it is determined from the detected voltage value that the operation switch is in a predetermined ON state. The motor drive control device for driving an electric tool according to claim 1 . The motor drive control device for driving an electric tool according to claim 1 or 2, further comprising a lock unit for fixing the trigger switch at an operation position where the trigger switch is in the predetermined ON state. Claim 1-3, characterized in that it comprises a notifying means for notifying the operator that the driving of the electric motor is operated is prevented the blocking means by the control unit A motor drive control device for driving an electric tool described in 1. 5. The motor drive control device for driving an electric tool according to claim 4 , wherein the notification means is constituted by a light emitting diode that is turned on or blinked by the control unit.

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