JP2020108284A - Dc power unit and electric tool system - Google Patents

Abstract

To provide a DC power unit which can improve workability when it is connected with an electric tool for performing regenerative brake and an electric tool system with the same.SOLUTION: In an electric tool system obtained by connecting an electric tool 70 with a DC power unit 1, the DC power unit 1 converts AC to be input from an AC power supply 3 into DC to be output to the electric tool 70. The DC power unit 1 comprises: an electrolytic capacitor 3; and resistors R6 and R7 connected in parallel with the electrolytic capacitor C3 on a secondary side of an isolation transformer 31. A switching element Qs is connected in series with the resistors R6 and R7. An operation part 40 controls conduction and shutdown of the switching element Qs according to a state of the electric tool 70.SELECTED DRAWING: Figure 6

Description

The present invention relates to a DC power supply device that converts an AC voltage input from an AC power supply into a DC voltage and supplies the DC power supply to the power tool, and a power tool system including the DC power supply device and the power tool.

A DC power supply device as shown in Patent Document 1 below includes a converter unit that converts an AC voltage of 100 V input from a commercial power supply or the like into a DC voltage of a desired voltage value lower than 100 V and outputs the DC voltage, and a cordless power tool. An adapter connectable to the battery pack connection part of (1) and a cable connecting the converter unit and the adapter to each other.

JP, 2005-278375, A

In the conventional DC power supply device, when regenerative braking (regenerative braking) is performed in the connected power tool and a regenerative current flows through the DC power supply device, the inter-terminal voltage at the output terminal of the DC power supply device increases. When the terminal voltage increases above a certain level, the overvoltage protection function operates on the electric tool side and the regenerative braking is stopped, so that a desired braking force cannot be obtained and workability deteriorates.

The present invention has been made in view of such a situation, and an object thereof is to provide a DC power supply device capable of improving workability when connected to an electric tool for performing regenerative braking, and an electric tool system including the same. To provide.

One aspect of the present invention is a DC power supply device. This DC power supply is
A DC power supply device, which is connected to an external AC power supply and an electric power tool, converts AC input from the AC power supply into DC, and outputs the DC power to the electric power tool,
An output terminal that outputs direct current by connecting to the power tool,
A transformer connected to the output terminal to transform the voltage input from the AC power source and supply the voltage to the output terminal.
A regenerative resistor portion electrically connected to the output terminal in parallel to the transformer portion,
A breaking unit capable of breaking the current path from the output terminal to the regenerative resistor unit,
A control unit for controlling conduction and interruption of the interruption unit,
The control unit controls conduction and interruption of the interruption unit according to a state of the electric power tool.

Connected to the power tool, a power supply side communication terminal to which the status signal of the power tool is input,
The control unit may control conduction and interruption of the interruption unit according to the state signal.

The control unit is
When the electric power tool is in the driving state of the motor, the interruption unit is interrupted,
The interruption unit may be made conductive when the electric tool is in a braking state of the motor.

A voltage detection circuit for detecting a voltage between the positive terminal and the negative terminal of the output terminal,
The control unit may control conduction and interruption of the interruption unit according to the voltage between the terminals.

The control unit is
When the voltage between the terminals becomes equal to or higher than a first threshold value in a state where the cutoff unit cuts off, the cutoff unit is turned on,
The cutoff unit may be cut off when the inter-terminal voltage becomes equal to or lower than a second threshold value in a state where the cutoff unit is conductive.

It is possible to interrupt the voltage input to the transformer unit, and a switching unit that is switched between conduction and interruption by the control unit,
The control unit may switch conduction and interruption of the switching unit based on the voltage between the terminals.

A capacitor electrically connected to the output terminal in parallel with the transformer and the regenerative resistor may be provided.

Another aspect of the invention is a power tool system. This power tool system
The DC power supply device,
An electric tool having an input terminal connected to the output terminal, and a motor driven by direct current input to the input terminal,
Equipped with.

Another aspect of the invention is a power tool system. This power tool system
The DC power supply device,
An electric tool having an input terminal connected to the output terminal, a motor driven by direct current input to the input terminal, and a tool-side communication terminal that outputs the status signal to the power-source-side communication terminal,
Equipped with
The status signal is a signal related to the driving status of the motor.

The electric power tool has an operation unit that is operated by an operator to switch between an ON state for driving the motor and an OFF state for stopping the motor,
The control unit is
When the operation unit is in the ON state, the blocking unit is blocked,
The interruption unit may be made conductive when the operation unit is in the off state.

The electric power tool has a braking means for performing regenerative braking on the motor when the operating portion is in the off state, and the braking means includes a positive electrode terminal of the input terminal and a positive terminal of the input terminal even when the operating portion is in the off state. The regenerative braking may be stopped when the inter-terminal voltage of the negative electrode terminal exceeds the brake operation release threshold value.

It should be noted that any combination of the above constituent elements, and the expression of the present invention converted between methods and the like are also effective as an aspect of the present invention.

According to the present invention, it is possible to provide a DC power supply device capable of improving workability when connected to an electric tool for performing regenerative braking, and an electric tool system including the same.

1 is a side view of an electric power tool 70 to which a DC power supply device 1 according to Embodiment 1 of the present invention and a second conversion unit 30 thereof are connected. The side view of the electric tool 70 with which the battery pack 80 was attached. FIG. 3 is a plan view of the DC power supply device 1 in which the upper cases of the first conversion unit 10 and the second conversion unit 30 are unfolded. The top view which shows the internal structure of the 1st conversion unit 10. The top view which shows the internal structure of the 2nd conversion unit 30. The circuit block diagram of the electric power tool system which connected the direct-current power supply device 1 and the electric power tool 70 mutually. 7 is a graph showing an example of temporal changes in the on/off state of the trigger switch 71 of the electric power tool 70, the voltage between the output terminals of the DC power supply device 1, and the rotation speed of the motor 74 in the electric power tool system of the first embodiment. In the power tool system of the comparative example in which the resistors R6 and R7 and the switching element Qs are removed from the DC power supply device 1, the on/off state of the trigger switch 71 of the power tool 70, the voltage between the output terminals of the DC power supply device 1, and the rotation of the motor 74. The graph which shows an example of the time change of a number. The circuit block diagram of the electric tool system which concerns on Embodiment 2 of this invention. 7 is a graph showing an example of a temporal change of an on/off state of a trigger switch 71 of an electric power tool 70A, an output terminal voltage of a DC power supply device 1A, and a rotation speed of a motor 74 in an electric power tool system according to a second embodiment.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same or equivalent components, members, and the like shown in the drawings are denoted by the same reference numerals, and duplicated description will be omitted as appropriate. In addition, the embodiments do not limit the invention, but are exemplifications, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

(Embodiment 1)
The present embodiment relates to a DC power supply device 1 and an electric tool system in which an electric tool 70 is connected to the DC power supply device 1. The front-back direction in the DC power supply device 1 is defined by FIG. The DC power supply device 1 includes a first conversion unit 10, a second conversion unit 30, and a cable 5. The first conversion unit 10 is connected to an external AC power source by a power cord 11. The second conversion unit 30 is detachably connected to the battery pack connecting portion 75 of the electric power tool 70. A battery pack 80 may be detachably connected to the battery pack connecting portion 75 of the electric power tool 70 as shown in FIG. When the operator turns on the trigger switch 71 of the power tool 70, drive power is supplied from the DC power supply device 1 or the battery pack 80 to the power tool 70. The power tool 70 is a hammer drill in the illustrated example, but the type is not limited as long as it is a power tool to which the battery pack 80 is detachably connected. The cable 5 connects the first conversion unit 10 and the second conversion unit 30 to each other. The cable 5 is preferably longer than the power cord 11. By sufficiently lengthening the cable 5, it is not necessary to float the first conversion unit 10 from the floor surface or the like when working with the electric power tool 70, and the worker does not need to support the weight of the first conversion unit 10, and the work can be performed. The property is good.

As shown in FIG. 3, a first cooling fan 17 is provided at the rear end of the first conversion unit 10. A second cooling fan 37 is provided at the rear end of the second conversion unit 30. The flow of cooling air generated by the first cooling fan 17 and the second cooling fan 37 is shown by arrows in FIG. The cooling air generated by the first cooling fan 17 is sucked in through the intake port 26 provided in the front part of the housing of the first conversion unit 10, and flows forward while cooling each component that constitutes the first conversion unit 10. The air is exhausted from an exhaust port 27 provided at the rear part of the housing. The cooling air generated by the second cooling fan 37 is sucked from the intake ports on both side surfaces of the housing of the second conversion unit 30, and is guided forward by the fins 41 and 42 while being blown to the front side of the second conversion unit 30. Each component is cooled, flows from the front to the rear in the central portion of the housing while cooling each component in the central portion in the width direction of the second conversion unit 30, and is exhausted from the exhaust port provided in the rear portion of the housing. ..

As shown in FIG. 4, the first conversion unit 10 is provided with components such as an electrolytic capacitor C1, a diode D1, a switching element Q1, a diode bridge 14, a triac 13 as a switching element, and an inductor L1. As shown in FIG. 5, the second conversion unit 30 is provided with components such as diodes D2 and D3, fins 41 and 42, electrolytic capacitors C2 and C3, an insulating transformer 31, and a switching element 32.

FIG. 6 is a circuit block diagram of the DC power supply device 1 and the electric power tool 70. In the first conversion unit 10, the two terminals connected to the external AC power supply 3 are first input sections. Of the connection terminals with the cable 5, two terminals (+ terminal 10b and − terminal 10c) connected to the output terminal of the boosting/smoothing circuit 25 are the first output section. The first conversion unit 10 includes a power factor correction circuit 12, a triac 13 as a cutoff circuit, a diode bridge 14 as a rectifier circuit, and a boosting/smoothing circuit 25. The input terminal of the power factor correction circuit is connected to the AC power supply 3. The peak value (first voltage value) of the AC voltage input from the AC power supply 3 is, for example, 80 V or more and less than 260 V.

The input terminal of the diode bridge 14 is connected to the output terminal of the power factor correction circuit 12. The triac 13 is provided in the current path between the power factor correction circuit 12 and the diode bridge 14. The triac 13 is provided to switch the output/cutoff of the first conversion unit 10. The diode bridge 14 rectifies the output current of the power factor correction circuit 12. The boosting/smoothing circuit 25 boosts the output voltage of the diode bridge 14. Of the boosting/smoothing circuit 25, the inductor L1, the diode D1, the switching element Q1, and the driver circuit 22 constitute a boosting circuit. The electrolytic capacitor C1 constitutes a smoothing circuit that smoothes the output voltage of the booster circuit. The voltage value (second voltage value) of the DC voltage output from the boosting/smoothing circuit 25, that is, the voltage value of the output voltage of the first conversion unit 10 is, for example, 200 V or more and less than 500 V. The second voltage value is higher than the first voltage value.

In the first conversion unit 10, the detection resistor R1 is provided in the path of the output current of the step-up/smoothing circuit 25 (the output current of the first conversion unit 10). The auxiliary power supply 15 converts the output voltage of the diode bridge 14 into an operating voltage (for example, DC5V) of the arithmetic unit 20 and the like. The current detection circuit 16 detects the output current of the boosting/smoothing circuit 25 based on the voltage across the detection resistor R1 and feeds it back to the arithmetic unit 20. The temperature detection circuit 19 includes a temperature detection element such as a thermistor, detects the temperature in the first conversion unit 10, and feeds it back to the calculation unit 20. The calculation unit 20 is an example of the first control unit and includes a microcontroller. The calculation unit 20 drives the first cooling fan 17 according to the temperature detection value by the temperature detection circuit 19. Further, the arithmetic unit 20 turns off the triac 13 when the abnormal temperature is detected by the temperature detection circuit 19, the abnormal current is detected by the current detection circuit 16, or the disconnection of the cable 5 is detected, and the operation unit 20 of the first conversion unit 10 is turned off. Turn off the output. One end of the resistor R2 is connected to a power supply line to which the output voltage of the auxiliary power supply 15 is supplied. The other end of the resistor R2 is connected to the arithmetic unit 20 and also connected to the energization signal transmission line 5a of the cable 5 via the abnormality detection terminal 10a. That is, the calculation unit 20 is connected to the energization signal transmission line 5a of the cable 5 via the abnormality detection terminal 10a. The reset terminal 18 is provided to return the arithmetic unit 20 to the initial state when the exchange of the cable 5 is completed after the arithmetic unit 20 turns off the triac 13 when the cable 5 is disconnected. By performing a reset operation on the reset terminal 18, the arithmetic unit 20 returns to the initial state and turns on the triac 13 again (in the non-cutoff state).

In the second conversion unit 30, two terminals (+ terminal 30b and − terminal 30c) connected to the input side of the insulating transformer 31 among the connection terminals for connecting to the cable 5 are the second input section. Of the connection terminals with the electric tool 70, the two terminals (+ terminal 30e and − terminal 30f) connected to both ends of the electrolytic capacitor C3 are the second output section (output terminal of the DC power supply device 1). The electrolytic capacitor C2 is provided between two terminals forming the second input section. The isolation transformer 31, the switching element 32 as a switching unit, the diodes D2 and D3, and the electrolytic capacitor C3 form a transformer unit. The switching element 32 is provided on the primary side of the isolation transformer 31. Diodes D2 and D3 are provided on the secondary side of the isolation transformer 31. The voltage on the secondary side of the insulating transformer 31 is smoothed by the electrolytic capacitor C3. The voltage value (third voltage value) of the DC voltage on the secondary side of the insulating transformer 31 is, for example, 0 V or more and less than 400 V, and particularly in the range of 0 V or more and less than 70 V, a voltage that matches the rated voltage of the power tool 70 to be connected. Is desirable. The third voltage value is lower than the second voltage value. The detection resistor R3 is provided in the path of the output current of the insulating transformer 31 and the electrolytic capacitor C3 (the output current of the second conversion unit 30). The current detection circuit 35 detects the output currents of the insulating transformer 31 and the electrolytic capacitor C3 based on the voltage across the detection resistor R3. The voltage detection circuit 34 detects the voltage across the isolation transformer 31. The switching control circuit 33 controls ON/OFF of the switching element 32 according to the current detection value of the current detection circuit 35 and the voltage detection value of the voltage detection circuit 34. The voltage detection value obtained by the voltage detection circuit 34 is also input to the calculation unit 40. The switching control circuit 33 and the calculation unit 40 form a control unit of the second conversion unit 30.

On the secondary side of the insulating transformer 31, in parallel with the electrolytic capacitor C3, resistors R6 and R7 forming a regenerative resistor section and a switching element Qs such as FET or IGBT as a cutoff section are provided. The resistors R6 and R7 are connected in parallel with each other. One ends of the resistors R6 and R7 are connected to the + terminal (positive electrode terminal) 30e. The other ends of the resistors R6 and R7 are connected to the drain of the switching element Qs. The source of the switching element Qs is connected to the-terminal (negative terminal) 30f via the resistor R3. The gate as a control terminal of the switching element Qs is connected to the arithmetic unit 40. The arithmetic unit 40 controls ON/OFF (conduction and interruption) of the switching element Qs according to the state of the electric tool 70. In the present embodiment, the arithmetic unit 40 controls ON/OFF of the switching element Qs according to the voltage detection value (voltage between the terminals of the + terminal 30e and the − terminal 30f) detected by the voltage detection circuit 34. Specifically, the arithmetic unit 40 turns off (interrupts) the switching element Qs while the inter-terminal voltage is less than the first threshold value, and switches the inter-terminal voltage in the off state (interrupted). Is above the first threshold value, the switching element Qs is turned on (conducted), and when the inter-terminal voltage is below the second threshold value while the switching element Qs is turned on (conducted), the switching element Qs is turned off again. Yes (block). The first threshold value is preferably a voltage value that is not reached when the electric power tool 70 is in a motor drive state. Further, the first threshold value is a voltage value smaller than a threshold value (brake operation release threshold value) at which the electric tool 70 stops regenerative braking by the overvoltage protection function. The second threshold value is a voltage value smaller than the first threshold value, and is preferably equal to or larger than the rated voltage of the electric power tool 70. The rated voltage of the power tool 70 in the present embodiment is 36V, the first threshold value is 45V, the second threshold value is 36V, and the brake operation release threshold value is 50V. When the switching element Qs is turned on, the switching element Qs is not turned off even when the inter-terminal voltage becomes equal to or lower than the second threshold value, and the switching element Qs is reduced only when the rotation speed of the motor 74 decreases to a predetermined value or less. May be turned off.

The auxiliary power supply 36 converts an input voltage from the cable 5 into an operating voltage for the switching control circuit 33, the arithmetic unit 40 and the like. The temperature detection circuit 38 includes a temperature detection element such as a thermistor, detects the temperature in the second conversion unit 30, and feeds it back to the calculation unit 40. The calculation unit 40 is an example of the second control unit and includes a microcontroller. The arithmetic unit 40 drives the second cooling fan 37 according to the temperature detection value by the temperature detection circuit 38. In addition, when the temperature detection circuit 38 detects an abnormal temperature, the calculation unit 40 transmits an OFF signal (abnormality detection signal) to the calculation unit 73 of the electric power tool 70 via the LD terminal, and stops the driving of the electric power tool 70. Resistors R4 and R5 are connected in series between the power supply line to which the output voltage of the auxiliary power supply 36 is supplied and the ground. The gate of the switching element Q3 is connected to the interconnection terminal of the resistors R4 and R5. The source of the switching element Q3 is connected to the ground. The drain of the switching element Q3 is connected to the energization signal transmission line 5a of the cable 5 via the abnormality detection terminal 30a. The resistors R4 and R5 and the switching element Q3 form a conduction signal generator.

When the cable 5 is not disconnected, the gate-source voltage of the switching element Q3 is positive and the switching element Q3 is on. Therefore, the abnormality detection terminals 30a and 10a have the ground potential. When the abnormality detection terminal 10a is at the ground potential (when there is an energization signal from the energization signal transmission line 5a), the calculation unit 20 determines that the cable 5 is not broken. When the cable 5 is broken, the voltage of the abnormality detection terminal 10a is pulled up by the resistor R2 to 5V. When the voltage of the abnormality detection terminal 10a becomes 5V while the DC voltage is being output from the first conversion unit 10 to the cable 5 (when the energization signal from the energization signal transmission line 5a disappears). Then, it is determined that the cable 5 is broken, the triac 13 is turned off, and the output of the first conversion unit 10 is cut off. In addition to the energization signal transmission line 5a, the cable 5 connects a + terminal 10b provided on the output side of the first conversion unit 10 and a + terminal 30b provided on the input side of the second conversion unit 30 with a + side power supply. It is a three-wire structure having a line 5b and a − side power supply line 5c that connects −terminal 10c provided on the output side of the first conversion unit 10 and −terminal 30c provided on the input side of the second conversion unit 30, In some cases, at least one of the + side power supply line 5b and the-side power supply line 5c is disconnected, and the energization signal transmission line 5a is not disconnected. In this case, the output voltage of the auxiliary power supply 36 disappears, the gate-source voltage of the switching element Q3 becomes 0, and the switching element Q3 turns off, so that the voltage of the abnormality detection terminal 10a is pulled up by the resistor R2. It becomes 5V.

In the electric power tool 70, the + terminal 70e and the-terminal 70f are input terminals connected to the + terminal 30e and the-terminal 30f (output terminal) of the DC power supply device 1. The electric power tool 70 includes a trigger switch 71 as an operation unit, an inverter circuit 72, a calculation unit 73 as a control unit, a motor 74, and an electrolytic capacitor C4. When the operator operates the trigger switch 71, the electric power tool 70 is switched between an on state in which the motor 74 is driven and an off state in which the motor 74 is stopped. A diode D4 for flowing a regenerative current is provided in parallel with the trigger switch 71. The electrolytic capacitor C4 is provided between the input terminals of the inverter circuit 72. The inverter circuit 72 has switching elements Q4 to Q9 such as FETs and IGBTs connected in a three-phase bridge. When the operator turns on the trigger switch 71, the electric tool 70 is in a motor drive state, and the arithmetic unit 73 controls the drive of the motor 74 by controlling the inverter circuit 72. Upon receiving the OFF signal (abnormality detection signal) from the arithmetic unit 40 of the second conversion unit 30 via the LD terminal, the arithmetic unit 73 turns off the inverter circuit 72 regardless of the state of the trigger switch 71, and drives the motor 74. To stop. The calculation unit 73 also functions as a braking device. When the operator turns off the trigger switch 71, the electric power tool 70 enters a motor braking state, and the calculation unit 73 controls the inverter circuit 72 to perform regenerative braking of the motor 74. Specifically, for example, the arithmetic unit 73 continuously or intermittently turns on at least one of the lower arm side switching elements Q4 to Q6 while keeping the upper arm side switching elements Q7 to Q9 off. .. By performing PWM control of at least one of the switching elements Q4 to Q6 on the lower arm side, it is possible to generate an arbitrary braking force by duty control. When the voltage between the + terminal 70e and the-terminal 70f exceeds the brake operation release threshold value, the calculation unit 73 stops the regenerative braking even if the trigger switch 71 is off.

FIG. 7 is a diagram showing an electric power tool system according to the first embodiment, in which the trigger switch 71 of the electric power tool 70 is turned on and off, the voltage across the output terminals of the DC power supply device 1 (the voltage between the positive terminal 70e and the negative terminal 70f), and the motor. It is a graph which shows an example of the time change of the number of rotations of 74. Before time t1, the trigger switch 71 is on, and the voltage between the output terminals of the DC power supply device 1 is a set value (a voltage that matches the rated voltage of the electric tool 70). When the trigger switch 71 switches from on to off at time t1, the calculation unit 73 starts regenerative braking of the motor 74. The arithmetic unit 73 turns on the switching element Qs when the inter-terminal voltage between the + terminal 70e and the − terminal 70f reaches the first threshold value (resistance ON threshold value) at time t2. When the switching element Qs is turned on, the regenerative energy of the motor 74 is consumed by the resistors R6 and R7, and the terminal voltage between the + terminal 70e and the-terminal 70f decreases. When the motor 74 is stopped at the time t3, the voltage between the + terminal 70e and the − terminal 70f becomes equal to the second threshold value, and the calculation unit 73 turns off the switching element Qs. Therefore, when the trigger switch 71 is turned on again, no current flows through the resistors R6 and R7. ..

FIG. 8 shows the ON/OFF state of the trigger switch 71 of the electric power tool 70, the voltage between the output terminals of the DC power supply device 1, and the power tool system of the comparative example in which the resistors R6 and R7 and the switching element Qs are removed from the DC power supply device 1. 7 is a graph showing an example of a change over time in the number of rotations of the motor 74. As in the case of FIG. 7, the calculation unit 73 starts regenerative braking of the motor 74 when the trigger switch 71 switches from on to off at time t1. The calculation unit 73 stops the regenerative braking when the voltage between the terminals of the + terminal 70e and the − terminal 70f reaches the brake operation release threshold value at time t4. After time t4, the motor 74 decelerates by natural deceleration. The time t5 at which the motor 74 stops is significantly delayed from the time t3 in FIG.

According to this embodiment, the following effects can be achieved.

(1) The DC power supply device 1 turns on the switching element Qs when the voltage between the output terminals increases due to the regenerative braking of the electric tool 70, and causes the regenerative energy to be consumed by the resistors R6 and R7. Therefore, in the electric power tool 70, even when the DC power supply device 1 is used as a power source, when the operator turns off the trigger switch 71, the motor 74 is quickly stopped by regenerative braking, so that workability can be improved.

(2) The DC power supply device 1 controls on/off of the switching element Qs according to the voltage detection value (voltage between the terminals of the + terminal 30e and the − terminal 30f) detected by the voltage detection circuit 34, and therefore controls the on/off of the switching element Qs. Therefore, it is not necessary to add a new configuration or function to the electric power tool 70. Therefore, the regenerative braking when the DC power supply device 1 is used as a power source can be easily applied to the existing electric tool 70.

(Embodiment 2)
The present embodiment relates to a DC power supply device 1A and an electric tool system in which a power tool 70A is connected to the DC power supply device 1A. FIG. 9 is a circuit block diagram of the electric power tool system according to Embodiment 2 of the present invention. Hereinafter, differences from the power tool system according to the first embodiment shown in FIG. 6 will be mainly described. The second conversion unit 30 of the DC power supply device 1A includes a power supply side communication terminal 30g. The electric power tool 70A includes a tool-side communication terminal 70g. The power supply side communication terminal 30g and the tool side communication terminal 70g are connected to each other. The calculation unit 40 of the second conversion unit 30 and the calculation unit 73 of the electric power tool 70A communicate with each other via the power supply side communication terminal 30g and the tool side communication terminal 70g. The calculation unit 73 outputs a state signal of the electric power tool 70A to the tool side communication terminal 70g. The state signal includes a signal indicating whether the motor 74 is in a driving state or a braking state such as turning on/off of the trigger switch 71. The arithmetic unit 40 of the second conversion unit 30 controls ON/OFF of the switching element Qs according to the state signal of the electric power tool 70A input to the power supply side communication terminal 30g. Specifically, the calculation unit 40 turns off the switching element Qs when the electric power tool 70A is in the motor driving state (the trigger switch 71 is in the on state), and the electric power tool 70A is in the motor braking state (the trigger switch 71 is in the off state). ), the switching element Qs is turned on.

FIG. 10 is a graph showing an example of temporal changes in the on/off state of the trigger switch 71 of the electric power tool 70A, the output terminal voltage of the DC power supply device 1A, and the rotation speed of the motor 74 in the electric power tool system according to the second embodiment. is there. 10 is different from FIG. 7 in that the voltage between the output terminals of the DC power supply device 1A does not increase even if the trigger switch 71 is switched from on to off at time t1. This means that immediately after the trigger switch 71 is turned off, the trigger switch 71 is turned off from the calculation unit 73 of the electric power tool 70A to the calculation unit 40 of the second conversion unit 30 of the DC power supply device 1A (the power tool 70A is a motor. This means that the calculation unit 73 turns on the switching element Qs after being informed that the vehicle is in the braking state.

The other points of the present embodiment are similar to those of the first embodiment. Similar to the first embodiment, the present embodiment can also improve the workability of the electric power tool 70A when the DC power supply device 1A is used as the power source. Further, according to the present embodiment, although the function of transmitting the status signal of the electric power tool 70A from the electric power tool 70A to the DC power supply device 1A is required, the function causes the second conversion unit 30 of the DC power supply device 1A to: Immediately after the trigger switch 71 of the electric power tool 70A is turned off, the switching element Qs is turned on and the consumption of regenerative energy by the resistors R6 and R7 can be started.

Although the present invention has been described with the embodiment as an example, it will be understood by those skilled in the art that various modifications can be made to each component and each process of the embodiment within the scope of the claims. By the way.

1, 1A DC power supply device, 3 AC power supply, 5 cables,
10 1st conversion unit, 11 power supply cord, 12 power factor improvement circuit, 13 triac, 14 diode bridge, 15 auxiliary power supply, 16 current detection circuit, 17 1st cooling fan, 18 reset terminal, 19 temperature detection circuit, 20 operation part (First control unit), 21 AND circuit, 22 driver circuit, 23 discharge resistance, 25 booster circuit, 26 intake port, 27 exhaust port,
30 2nd conversion unit, 31 insulating transformer, 32 switching element, 33 switching control circuit, 34 voltage detection circuit, 35 current detection circuit, 36 auxiliary power supply, 37 2nd cooling fan, 38 temperature detection circuit, 40 operation part (2nd Control unit),
70 electric tool, 71 trigger switch, 72 inverter circuit, 73 arithmetic unit, 74 motor, 75 battery pack connecting unit,
80 battery pack

Claims (11)

A DC power supply device, which is connected to an external AC power supply and an electric power tool, converts AC input from the AC power supply into DC, and outputs the DC power to the electric power tool,
An output terminal that outputs direct current by connecting to the power tool,
A transformer connected to the output terminal to transform the voltage input from the AC power source and supply the voltage to the output terminal.
A regenerative resistor portion electrically connected to the output terminal in parallel to the transformer portion,
A breaking unit capable of breaking the current path from the output terminal to the regenerative resistor unit,
A control unit for controlling conduction and interruption of the interruption unit,
The said control part is a direct-current power supply device which controls conduction|electrical_connection and interruption|blocking of the said interruption|blocking part according to the state of the said electric tool. Connected to the power tool, a power supply side communication terminal to which the status signal of the power tool is input,
The DC power supply device according to claim 1, wherein the control unit controls conduction and interruption of the interruption unit according to the state signal. The control unit is
When the electric power tool is in the driving state of the motor, the interruption unit is interrupted,
The DC power supply device according to claim 2, wherein when the electric power tool is in a braking state of a motor, the cutoff portion is brought into conduction. A voltage detection circuit for detecting a voltage between the positive electrode terminal and the negative electrode terminal of the output terminal,
The DC power supply device according to claim 1, wherein the control unit controls conduction and interruption of the interruption unit according to the voltage between the terminals. The control unit is
When the voltage between the terminals becomes equal to or higher than a first threshold value in a state where the cutoff unit cuts off, the cutoff unit is turned on,
The DC power supply device according to claim 4, wherein when the voltage between the terminals becomes equal to or lower than a second threshold value in a state where the cutoff unit is conductive, the cutoff unit is cut off. It is possible to interrupt the voltage input to the transformer unit, and a switching unit that is switched between conduction and interruption by the control unit,
The DC power supply device according to claim 4, wherein the control unit switches conduction and interruption of the switching unit based on the voltage between the terminals. The DC power supply device according to claim 1, further comprising a capacitor electrically connected in parallel to the transformer and the regenerative resistor, the capacitor being connected to the output terminal. A DC power supply device according to any one of claims 1 to 7,
An electric tool having an input terminal connected to the output terminal, and a motor driven by direct current input to the input terminal,
An electric power tool system equipped with. The DC power supply device according to claim 2 or 3,
An electric tool having an input terminal connected to the output terminal, a motor driven by direct current input to the input terminal, and a tool-side communication terminal that outputs the status signal to the power-source-side communication terminal,
Equipped with
The power tool system, wherein the status signal is a signal related to a driving status of the motor. The electric power tool has an operation unit that is operated by an operator to switch between an ON state for driving the motor and an OFF state for stopping the motor,
The control unit is
When the operation unit is in the ON state, the blocking unit is blocked,
The electric power tool system according to claim 9, wherein the cutoff portion is brought into conduction when the operation portion is in an off state. The electric power tool has a braking means for performing regenerative braking on the motor when the operating portion is in the off state, and the braking means includes a positive electrode terminal of the input terminal and a positive terminal of the input terminal even when the operating portion is in the off state. The electric tool system according to claim 10, wherein the regenerative braking is stopped when the voltage between the terminals of the negative electrode exceeds a brake operation release threshold value.

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