JP2001245462A - Portable motor power device and power tool equipped with it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a portable motor power device, operated by a battery pack or an AC power source, which is no less in size, weight and cost than a conventional portable motor power device for a large power use operated only by a battery pack. SOLUTION: The portable motor power device is provided with a DC motor 5 as its power device, a cordless power source 2 containing a battery cell 7, a corded power feeder 3 containing a converter 6 which converts a current of AC power source to a DC current, and a connecting part 8 which selectively connects the cordless power source or the corded power feeder electrically and mechanically to its device main body 1. The supply voltages of the power sources 2 and 3 is differentiated and coping with the different voltages the rotor winding 10 of the DC motor is composed of a multiplex winding, and meeting the multiplex winding, a plurality of brushes 12 and a commutator 13 are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable device (equipment) operated by a motor, and more particularly, to a device operated in both a cordless state using a battery power supply and a state connected to an AC power supply via a power cord. Motor power unit that can be used.

[0002]

2. Description of the Related Art A cordless motor power unit generally includes a removable closed battery pack housed in a housing. The battery pack contains one or more battery cells and supplies DC power required for operation of the device.

When such a device is used in a place where a normal AC power source can be obtained, it is necessary to connect the AC power source to the AC power source with a power cord so that the AC power source can be used as an external power source. Because it is preferable in terms of usability, in devices such as shavers, tape recorders, and video cameras that consume relatively little power, have a relatively constant load state, and have small current fluctuations, supply power to the low-voltage DC motor. For this purpose, an AC power supply is provided with an input terminal that can be connected via an AC adapter composed of a combination of a transformer and a rectifier, or an AC power supply having a built-in AC adapter.

[0004]

Among devices using a battery pack, there are portable power tools such as an electric drill, an electric screwdriver, an electric impact drill, and an electric circular saw, and garden equipment such as a lawnmower. The power consumption of these devices is much larger than that of the above devices, and the current fluctuation is very large because the load fluctuation is large. At present, a battery pack for supplying power to a device having a large current fluctuation with high power and a low-voltage DC motor driven by the battery pack are currently generally used technical means.

[0005] However, when the apparatus provided with the DC motor for low voltage and large current is connected to an AC power supply via a power cord and the AC power supply is used as an external power supply, the combination of the above-described transformer and rectifier is used. Utilization requires a transformer having a capacity for a large current, so that a very large and heavy AC / DC converter must be mounted on the equipment. For portable tools, garden appliances, and many household appliances, excessive size and weight are very significant drawbacks.

[0006] On the other hand, Japanese Patent Publication No. 2859341 discloses that
Means of an AC / DC converter for converting an AC power supply voltage to a predetermined frequency higher than the power supply voltage frequency and then converting it to a rectified predetermined DC low voltage is disclosed. When this means is used, the size and weight can be significantly reduced in size and weight as compared with the above-described AC / DC converter using a transformer and a rectifier.

[0007] However, the above-mentioned system provided with a frequency converter and a step-down converter is also employed in a separate charger attached to a rechargeable tool driven by a rechargeable battery pack, for example. As is clear from the above, mounting on a portable device body has not yet reached a practical level in terms of size, weight and cost.

[0008] The present invention has been made in view of the above points, and despite the fact that it can cope with high power and can use both a battery pack and an AC power supply as power supplies, It is an object of the present invention to provide a portable motor power unit that operates only with a pack and is not inferior in size, weight, and cost to a high power portable motor power unit.

[0009]

SUMMARY OF THE INVENTION A portable motor power unit according to the present invention comprises a DC motor as a power unit, a cordless power supply unit having a built-in battery cell, and a unit for converting a current from an AC power supply to a DC. A connecting part for selectively electrically and mechanically connecting the built-in power supply device with a cord to the device main body is provided, and the supply voltage of the power supply device is made different, and a DC motor is provided so as to be able to cope with different supply voltages. , And a plurality of brushes and commutators corresponding to the multiple windings are provided.

At this time, the multiplex winding of the rotor of the DC motor is designed so that the obtained motor drive characteristics are the same regardless of which of the plurality of power supply devices is connected. It is preferable to keep it.

Also, a power supply path from the cordless power supply to the low voltage winding of the DC motor and a power supply path from the corded power supply to the high voltage winding of the DC motor are described. Preferably, they are separated.

The DC motor used here is a DC 2.4 V
Low voltage winding corresponding to 48V, DC 100V-30
It is preferable to use a double winding including a high-voltage winding corresponding to 0 V, but the present invention is not limited to this.

The cordless power supply device may be a battery pack containing a chargeable / dischargeable secondary battery, and the corded power supply device may be an AC adapter pack having substantially the same shape as the battery pack.

In this case, the battery pack includes a fitting portion inserted and connected to the connecting portion, and a connecting terminal provided on the fitting portion and connected to the low-voltage power receiving terminal portion. And a high-voltage output connector provided adjacent to the fitting portion and connected to the high-voltage power receiving terminal portion.

Preferably, the AC adapter pack has a ground wire and a high voltage output connector having a ground connection terminal connected to the motor via a high voltage power receiving terminal.

Further, a board on which means for converting a current from an AC power supply to DC is mounted is incorporated in the AC adapter pack, and a ground connection terminal and a ground wire are connected via a ground line formed on the board. Preferably, a noise removing capacitor is connected to the ground line.

It is preferable that the cord drawn from the corded power supply device has its drawer portion rotatable. At this time, there is provided a click generating means for generating clicks at a plurality of positions within the rotation range of the drawer portion. Preferably. The click generating means may generate a click only at both ends of the rotation range of the drawer.

Further, among a plurality of rotor windings constituting a multiplex winding of the rotor, a rotation speed detecting means for detecting a motor rotation speed from an alternating potential generated in a rotor winding to which no voltage is applied is provided. It is also preferred to have one.

An overload protection device for interrupting a circuit when an overload occurs is preferably inserted in a power line from the corded power supply device to the DC motor.

The overload protection device may be disposed inside the corded power supply device or inside the device body of the power plant, but it is preferable to use a bimetallic thermostat that operates due to a rise in temperature. It is preferable that it be inserted and arranged in the AC circuit portion before full-wave rectification.

[0021] In addition to the overload protection device, which is a bimetallic thermostat that operates according to a temperature rise, a second overload protection device that operates in a temperature range higher than that of the thermostat may be provided. For the second overload protection device, a fuse that blows due to a rise in temperature and cuts off the circuit can be suitably used.

The electric power tool according to the present invention includes a T-shaped housing including a cylindrical portion and a grip portion projecting from the center of the cylindrical portion, and includes a DC motor and a switch for controlling power supply in the housing. A power supply device having a built-in battery cell and a power supply device with a cord having a means for converting current from an AC power supply to DC can be selectively detachably attached. The DC motor has a double winding and includes a plurality of brushes and a commutator matched to the double winding, and among a plurality of brushes respectively connected to the double winding, The brush for low-voltage driving, which receives power from the cordless power supply device, is located at the tip of the tool, and the brush for high-voltage driving, which receives power from the power supply device with cord, is located at the rear end of the tool. It has a feature to the door.

It is preferable that the DC motor has a built-in cooling air discharge type fan, and the fan is located near the low voltage driving brush.

When providing an overload protection device for interrupting a circuit when an overload occurs, it is preferable to provide the overload protection device in a grip portion of a housing, and particularly preferably in the vicinity of an electrical connection portion with a corded power supply device. .

[0025]

FIG. 1 shows an example of an embodiment of the present invention.
A description will be given based on FIGS. 1 and 2 show a power tool provided with the portable motor power unit according to the present invention, and FIG. 1 shows a means 6 for converting a current from an AC power source to a direct current.
FIG. 2 shows a power tool with an AC adapter pack 16 as a corded power supply device 3 having a built-in power supply.
Shows a power tool in a state where a battery pack 15 which is a cordless power supply device 2 including a plurality of battery cells 7 is mounted.

The housing 1 of the main body 1 of the electric power tool
Reference numeral 7 denotes a cylindrical portion 17a and a grip portion 17b protruding downward from the middle of the cylindrical portion 17a. A DC motor 5 as a power unit is provided at a rear portion of the cylindrical portion 17a, and a reducer 18 for reducing the rotational output of the DC motor 5 is provided at a front portion thereof. A chuck 19 connected to the output shaft 5a of the DC motor 5 via a speed reducer 18 is provided at the end.

The supply of electric power to the DC motor 5 is performed by opening and closing a contact in a switch 20 provided in the holding portion 17b by operating the trigger lever 21. The switch 20 has a terminal 22a for receiving power supply from the battery pack 15, and has an A
A terminal 23a for receiving power supply through the C adapter pack 16 is connected via a lead wire 24. These terminals 22a and 23a are connected to a power terminal 22b of the battery pack 15 and a power supply of the AC adapter pack 16, respectively. It can be electrically coupled to the terminal 23b.

A plurality of battery cells 7 are housed in series in the battery pack 15 so that a predetermined power supply voltage can be generated. Further, a circuit 25 for rectifying and smoothing the current from the AC power supply and converting it to DC is provided in the AC adapter pack 16. The circuit 25 outputs a DC of about 130 V when the AC power supply is 100 V.

Further, the battery pack 15 and the AC adapter pack 16 are provided with a hook 26b for mechanically connecting and holding the battery pack 15 and the AC adapter pack 16 when the battery pack 15 and the AC adapter pack 16 are inserted into the gripping section 17b. Receiving part 26 of 26b
a is provided. As described above, the connection portion 8 that can electrically and mechanically interchange the battery pack 15 and the AC adapter pack 16 is provided in the apparatus main body 1.

Next, the DC motor 5 driven by the plurality of supply voltages will be described. FIG. 3 is a cutaway side view of the DC motor 5 and FIG. 4 is a cross-sectional view of the rotor 9 of the DC motor 5. The DC motor 5 shown here is
It is a DC drive brush magnet motor.
In the magnetic field of the magnet 29 disposed on the inner wall 28a of the motor, a current flows through the brush 12 and the commutator 13 to the rotor winding 10 disposed on the rotor iron core 31 fixed to the shaft 30. Has a structure in which the rotor 9 has a rotating force and rotates while being supported by the bearing 35. In this case, in order to be able to drive at a plurality of supply voltages, that is, both low voltage and high voltage, , A rotor winding 10a through which current flows through the low-voltage brush 12a and the low-voltage commutator 13a, the high-voltage brush 12b and the high-voltage commutator 13
The two windings 10a and 10b of the rotor winding 10b, through which a current flows through the rotor core b, are formed as multiple windings arranged on a rotor iron core 31.

The battery pack 15 normally has a DC voltage of 2.
4-48V, 7.2V-24 for power tools
The rectified and smoothed DC voltage from the AC power supply is about 100 V to 300 V, depending on the type of AC power supply, and is about 130 V when the AC power supply is 100 V AC as described above. Thus, the rotor winding 10 of the DC motor 5
Has a multiple winding structure and a plurality of brushes 12 and commutators 13 adapted to the multiple windings, so that the low voltage of the battery pack 15 and the high voltage rectified and smoothed by the AC adapter pack 16 from the AC power supply. Can be driven with both supply voltages.

The alternating current is converted into a high-voltage direct current and supplied to the direct-current motor 5, and the rotor winding 1 is operated so that the direct-current motor 5 operates even at the high-voltage direct current.
0b, the AC adapter pack 16
May have a built-in circuit 25 that only rectifies and smoothes the current from the AC power supply and converts it to DC. Since this circuit configuration is simple, the size of the battery pack 15 is small.
It is possible to reduce the size and weight of the cabtire cable 27, and the cost of the cabtire cable 27 can be increased.

FIG. 5 is a block diagram of the driving path,
Reference numeral 2 denotes an input switching unit that switches input power by inserting either the battery pack 15 or the AC adapter pack 16.

The above two rotor windings 10a, 10a
The respective motor drive characteristics (rotational speed-torque characteristics) by b are substantially equal. That is, the no-load rotation speed is uniquely determined by the supply voltage V and the number of turns n of the rotor windings. In the case of an AC power supply, the balance between the contact resistance of each part and the coil resistance can be made equal by adjusting the balance of the coil wire diameter or the like. Therefore, even if a plurality of power supply devices having different supply voltages are used, the motor drive characteristics of the device can always be kept constant by appropriately designing the multiple windings of the rotor 9 of the DC motor 5.

FIGS. 6 to 9 show other examples. The basic configuration is the same as that described above, and the battery pack 1 shown in FIG.
5 is connected to the low-voltage rotor winding 1 of the DC motor 5.
A current is supplied to the high-voltage rotor winding 10b of the DC motor 5 when the AC adapter pack 16 shown in FIG. 7A is connected. Voltage brush 12b and high voltage commutator 1
The current is supplied via the switch 3b. Here, as the switch 20 which is opened and closed by the operation of the trigger lever 21, a switch having a low-voltage switching contact 20a and a high-voltage switching contact 20b is used. Thus, the power supply path from the battery pack 15 to the low-voltage rotor winding 10a of the DC motor 5 and the power supply path from the AC adapter pack 16 to the high-voltage rotor winding 10b of the DC motor 5 are completely completed. Are separated.

FIGS. 18 to 22 show the switch 20 used here. The switch 20 includes, in addition to the two switching contacts 20a and 20b, a control element C of the control circuits C1 and C2 for speed control of the DC motor 5.
3, a short-circuit contact portion 20c for bypassing C4,
20d, and contact portions 50 and 51 that are switched by a lever 55 that is rotated by operation of a rotation direction switching lever 58 shown in FIG.
19a to 20d, as shown in FIGS. 19 and 20, are opened and closed by seesaw movement of four contact plates 200, 201, 202, and 203. The movable plate 21a integrated with the trigger lever 21 is used as a spring. The four sliding members 211, 212, 213, 214 that are being urged are operated by the operation of the trigger lever 21 so that the contact plates 200, 201,
When moving on 202, 203, each contact plate 200, 201,
202, 203 are the fulcrums 205, 206, 207, 2
08 when the sliders 211, 212, 213, and 214 cross over, and the contact portions 20a to 20d are opened and closed. The positions of the fulcrums 205, 206, 207 and 208 are shown in FIG.
As shown by 0, when the trigger lever 21 is pulled, the switching contact 20a for low voltage is closed first, then the switching contact 20b for high voltage is closed, and then the contacts 20c and 20d for short-circuit are closed. It has become. The control circuits C1 and C1
The description of the detection unit input to 2 is omitted here. Also,
The contact plate 201 for the low-voltage switching contact 20a closes the brake contact 20f that short-circuits the low-voltage rotor winding 10a when the low-voltage switching contact 20a is open.

The contact portions 50 and 51 are respectively provided with two switching contact plates 50a, 50b, 51a and 51b on both end surfaces in the axial direction of a rotating body 56 which rotates integrally with the lever 55. Connection relationship between the four terminal plates 500, 501, 502, and 503 disposed on one end in the direction, and four terminal plates 51 disposed on the other end in the axial direction of the rotating body 56.
0, 511, 512, 513 and the connection
Contact plates 50a, 50b, 51 in accordance with the rotation of
a, 51b, the terminal plates 500, 501
Is connected to the high voltage brush 12b of the DC motor 5,
The terminal boards 502 and 503 are connected to the AC adapter pack 16 input. The terminal plates 510 and 511 are connected to the low voltage brush 12a of the DC motor 5, and the terminal plates 502 and 503 are connected to the input of the battery pack 15.

The DC motor 5 used here
Is a low-voltage brush 12a
And a low-voltage commutator 13a, and a high-voltage brush 12b and a high-voltage commutator 13b at the rear end. The built-in cooling air discharge fan 40 includes a low-voltage brush 12a. In the vicinity. Brush 12 for low voltage
Since a large current flows on the a side, heat radiation on the low voltage side is more effectively performed, and
The arrangement of the lead wire for connection with the switch 20 arranged in the inside 7a can be shortened.

The AC adapter pack 16 used here is the same as the battery pack 15 in the housing 1.
5 is located beside the fitting portion 45 which is inserted into the grip 17a.
Power terminal 23b formed as a pin connector
Is arranged. Of course, the corresponding terminal 23a is also a 5-pin connector. As shown in FIG. 9, the use of the 5-pin connector is such that the switching contact 20b is inserted between the AC power supply and the rectifying / smoothing circuit 25 to perform switching with the power supply before rectification. And a ground wire 70 having one end connected to the casing of the DC motor 5 is connected to the power cord 2.
This is because it is possible to connect to the ground terminal 27a through the built-in ground wire. The ground pin 700 of the terminal 23a is longer than other pins for preventing electric shock.

The ground wire 70 passes through the inside of the AC adapter pack 16. At this time, as shown in FIG. 25, the ground wire 70 passes through the ground line on the substrate 250 on which the rectifying and smoothing circuit 25 is mounted. , Are connected to noise removal capacitors Ca and Cb mounted on the substrate 250. As shown in FIG. 24, noise removal measures are easier than when the ground line on the substrate 250 is not passed.

The AC adapter pack 16 used here is provided with a rotating case 60 at the base end side of a cord bush 68 which is a lead-out portion of the power cord 27,
It is attached so as to be rotatable with respect to the adapter pack 16. That is, by projecting the shaft portion 61 from both side surfaces of the rotating case 60 and receiving the shaft portion 61 by the housing of the AC adapter pack 16, the rotating case 60 and the cord bush 68 are vertically lowered from the rear (horizontal direction). It is rotatable within a range of approximately 90 ° up to. Code 2
16 can be changed in the drawing direction.
In addition to being able to stand upright as shown in FIG. 17, the cord 27 can be positioned in a direction that does not hinder the work as shown in FIG.

Further, a plurality of click recesses 62 are provided on the outer peripheral surface of the shaft portion 61, as shown in FIG.
2, the cord 27 can be held in a predetermined direction. The above click is the rotation case 6
Although it is set to occur at a plurality of positions in the rotation range of 0, it is also preferable that the click is generated only at both ends of the rotation range, that is, only when the cord 27 is oriented in the horizontal direction and the vertical direction. In normal use, as shown in FIG. 17, the cord 27 naturally faces downward, and can be held horizontally and vertically only when the user intends. This is because workability can be obtained.

By the way, in the DC-driven brush magnet motor having the multi-winding structure as in this embodiment, the voltage is applied to any one of the rotor windings 10, and the remaining rotor windings 10 The motor 10 operates as a generator instead of an electric motor. If the generated alternating potential is taken out, the winding 10 can be used as a frequency generator. be able to. FIG. 23 shows that, in the DC motor 5 having two windings, the other winding to which no voltage is applied can be used as the rotation speed detecting means of the motor to perform the feedback control of the rotation speed. Showing things.

Further, upon driving with the above two power sources,
In the event of thermal breakdown due to motor temperature rise during low voltage driving, there is no danger of sparking or ignition even with smoke, whereas in the case of high voltage driving, heat breakdown due to motor temperature rise , Which can range from smoke to ignition,
Compensation for user safety and property protection cannot be expected.

FIG. 26 shows an example in view of this point.
Here, a bimetal thermostat 100 as an overload protection device is inserted and arranged in the AC circuit portion before full-wave rectification in the AC adapter pack 16 on the high voltage driving circuit side, and a fuse as a second protection device is provided. 101 is arranged between the contact portion 50 and the DC motor 5.
Here, the thermostat 100 is arranged in the AC circuit portion for the following reason. That is, when the bimetal thermostat 100 is inserted and arranged in a DC circuit portion having a high voltage of 100 V or more, an arc is easily generated when the contacts are opened and closed, and the contact contact resistance increases due to the occurrence of contact wear and blackening. This is because there is a possibility that the contact may be welded by pulling, but when the antenna is inserted and arranged in the AC circuit portion, such an arc hardly occurs.

As shown in FIG. 27, when the working time (motor driving time) is plotted on the vertical axis and the working current (motor applied current) is plotted on the horizontal axis, the limit line leading to smoke and ignition due to overcurrent of the DC motor 5 is shown. Represents a quadratic curve as shown in the figure (a is a smoke line for the motor, b is a burnout line for the motor), and the thermistor 100 and the fuse 10
The operation diagram of FIG. 1 also draws a quadratic curve (the thermostat operation line in the figure, and the fuse operation line in FIG. 2) along the above limit line, but the fuse 101 is blown in a temperature range lower than the limit line leading to smoke and ignition. However, the thermostat 101 operates in a lower temperature range to cut off the current.

That is, before the DC motor 5 is damaged by heat, the thermostat 1 as the first overload protection device is
00 protects the DC motor 5 in order to cut off the current by operating, and even if the thermostat 100 is broken and the contacts are welded, etc., the fuse which is the second overload protection device is used. The DC motor 5 is protected by the fusing of the DC motor 101, so that the DC motor 5 does not break down due to heat and cause smoke and ignition.

Here, the thermostat 100 is arranged in the AC adapter pack 16 because the battery pack 1
When there are a plurality of motor power units that can share the DC power supply 5 and the AC adapter pack 16, even if the thermostat 100 is not installed for each motor power unit, the thermal destruction of the DC motor 5 in each motor power unit when overloaded is prevented. As shown in FIG. 28, the thermostat 100 may be inserted and arranged in a power supply circuit portion that is folded back into the AC adapter pack 16 in the housing 17, as shown in FIG. When the bimetal thermostat 100 is arranged on the main body side of the motor power unit in this manner,
Temperature rise characteristics of DC motor 5 and thermostat 100
There are a plurality of types of motor power units that can easily use the battery pack 15 and the AC adapter pack 16 in particular, and the temperature rise characteristics of the DC motor 5 in these motor power units are different. In such a case, no problem occurs.

When arranging the thermostat 100 in the housing 17, as shown in FIG.
The thermostat 100 is connected to the AC circuit portion returning to the rectifier circuit 25 in the AC adapter pack 16 by disposing the thermostat 100 in the grip portion 17b of the housing 17 and near the electrical connection portions 23a and 23b to the AC adapter pack 16. In this case, it is possible to reduce the length of the lead wires, and by locating it away from the vicinity of the DC motor 5 which is a heat source, the influence of the heat generated by the DC motor 5 can be reduced.
Is not received. The fuse 101 has a cylindrical portion 17a of the housing 17.
Located in the rear end.

[0050]

According to the first aspect of the present invention, the supply voltage obtained by converting from an AC power supply to a DC power can be set to a high voltage, even in a device with large power consumption. The corded power supply device can be reduced in size and weight, and the corded power supply device can be made compatible with a cordless power supply device in dimensions and dimensions. In addition, since the circuit configuration of the power supply device with a cord is simple, the cost can be reduced in comparison with a portable motor power device for high power that operates only with a conventional battery pack. .

According to the second aspect of the present invention, in addition to the effects of the first aspect, any one of the cordless power supply apparatus and the corded power supply apparatus can be selected. , The same motor drive characteristics are obtained,
An easy-to-use portable motor power unit can be realized.

According to the third aspect of the present invention,
Separate the power supply path from the cordless power supply to the low voltage winding of the DC motor and the power supply path from the corded power supply to the high voltage winding of the DC motor. Therefore, it is possible to avoid an increase in size due to an insulation distance or a current capacity, which is a problem when a path is shared, and to keep a small size.

In the invention according to claim 4,
Normally used battery packs are provided by using a DC motor as a double winding having a low voltage winding corresponding to DC 2.4 V to 48 V and a high voltage winding corresponding to DC 100 V to 300 V. And various AC power supplies.

Further, in the invention according to claim 5,
The cordless power supply device is a battery pack containing a rechargeable secondary battery, and the corded power supply device is an AC adapter pack that has substantially the same shape as the battery pack. The power supply device and the power supply device can be selectively attached to a single mounting portion, so that the number of components can be reduced and the weight can be reduced by sharing the mounting portion.
By adjusting the shape of the adapter pack, it is possible to provide a device that can directly use the existing battery pack.

In the invention according to claim 6,
The battery pack includes a fitting portion inserted and connected to the connection portion, and a connection terminal provided in the fitting portion and connected to the low-voltage power receiving terminal portion, and the AC adapter pack is inserted into the connection portion. When the battery pack is shared with another rechargeable device because it includes the fitting portion and the high-voltage output connector provided adjacent to the fitting portion and connected to the high-voltage power receiving terminal portion. In addition, the AC adapter pack cannot be attached to other rechargeable devices due to its high voltage output connector, thereby improving safety and preventing misuse.

According to the seventh aspect of the present invention,
Since the AC adapter pack has a ground wire and the high voltage output connector has a ground connection terminal connected to the motor via the high voltage power receiving terminal portion,
In addition to the fact that the motor charging section is not double-insulated, the ground can be taken, and the ground cord does not interfere with operation when using a battery pack that does not require grounding.

In the invention according to claim 8,
The AC adapter pack incorporates a board on which a means for converting a current from an AC power supply to DC is mounted, and a ground connection terminal and a ground wire are connected via a ground line formed on the board. Since the noise removing capacitor is connected to the ground line, noise can be easily removed.

According to the ninth aspect of the present invention,
The cord that is pulled out from the power supply unit with cord is rotatable so that the cord does not become a hindrance even when working in a narrow place. Can be improved.

According to the tenth aspect of the present invention, since click generating means for generating clicks at a plurality of positions in the rotation range of the drawer portion is provided, higher workability can be obtained. it can.

According to the eleventh aspect of the present invention, the click generating means generates clicks only at both ends of the rotation range of the drawer. In this case, the cord can be held horizontally or vertically below, and high workability can be obtained.

According to the twelfth aspect of the present invention, of the plurality of rotor windings constituting the multiplex winding of the rotor, the alternating potential generated in the rotor winding to which no voltage is applied is provided. Since the rotation speed detecting means for detecting the rotation speed of the motor is provided, it is possible to cope with the rotation speed control without separately providing a sensor for detecting the rotation speed.

According to the thirteenth aspect of the present invention, an overload protection device for interrupting a circuit when an overload occurs is inserted and arranged in a power line from a corded power supply device to a DC motor. In addition, it is possible to prevent thermal destruction at the time of motor overload, and to assure user safety.

In the invention according to claim 14, since the overload protection device is disposed inside the corded power supply device, a plurality of corded power supply devices can be shared. In this case, the protection can be performed without providing an overload protection device for each power device, and the cost of the system can be reduced.

Further, in the invention according to claim 15, since the overload protection device is disposed in the device body of the power plant, the power device incorporates the operating characteristics of the overload protection device. It can be adapted to the characteristics of the motor and can provide more reliable protection.

In the invention according to the sixteenth aspect, since a bimetallic thermostat which operates due to a rise in temperature is used as the overload protection device, the temperature rise of the motor and the operation of the overload protection device are reduced. And secure protection can be provided.

According to the seventeenth aspect of the present invention, since the overload protection device is inserted in the AC circuit portion before full-wave rectification, an arc is generated when the overload protection device operates and returns. It hardly occurs, and problems caused by arc generation can be avoided.

According to the present invention, in addition to the overload protection device, which is a bimetallic thermostat that operates when the temperature rises, the second overload that operates in a temperature range higher than the thermostat. Since the protection device is provided, protection can be provided even in the event that the thermostat is broken and contact welding or the like is caused.

Further, in the invention according to claim 19, since the second overload protection device uses a fuse that blows due to a rise in temperature and cuts off the circuit,
If the fuse is also blown, it cannot be operated as a motor power unit. However, the fact that the fuse, which is the second overload protection device, is blown means that the first overload protection device is broken. Therefore, it is possible to eliminate the danger of continuous use as it is, and to prompt the user to repair the device.

A power tool according to a twentieth aspect of the present invention includes a T-shaped housing having a cylindrical portion and a grip portion projecting from the middle of the cylindrical portion, and a DC motor is provided in the housing. A power supply device having a switch for controlling power supply and a cordless power supply device having a built-in battery cell, and a power supply device having a cord having a means for converting current from an AC power supply to DC. The DC motor has a double winding and is provided with a plurality of brushes and commutators adapted to the double winding, and is connected to the double winding, respectively. Of the plurality of brushes, the low-voltage driving brush that receives power supply from the cordless power supply device is at the tool tip side, and the high-voltage driving brush that receives power supply from the corded power supply device is after the tool. Side, the higher current flows than the higher voltage side, and the copper loss in the lead wire becomes larger.The lower voltage side lead wire can be shortened to increase the electrical efficiency. it can.

According to the twenty-first aspect of the present invention, in addition to the effect of the thirteenth aspect, the DC motor has a built-in cooling air discharge type fan, and the fan is Since it is located in the vicinity of the low-voltage driving brush, the heat radiation is also good, so that the electrical efficiency can be further increased.

In the invention according to the twenty-second aspect, since the overload protection device that cuts off the circuit when overloaded is provided in the holding portion of the housing, the overload protection device is a heat source. Can be prevented from being affected by the heat, and an appropriate operation can be performed by the overload protection device.

Further, in the invention according to claim 23, since the overload protection device is disposed near the electrical connection with the corded power supply device, the overload protection device in the tool body is provided. Even when the protection device is connected to the AC circuit portion before rectification by the rectification circuit in the corded power supply device, it is possible to reduce the lead wires, to improve the assemblability, and to reduce the size. be able to.

[Brief description of the drawings]

FIG. 1 is an example of an embodiment of the present invention, and is a cutaway side view of a power tool equipped with an AC adapter pack.

FIG. 2 is a cutaway side view of the power tool equipped with the battery pack.

FIG. 3 is a cutaway side view of a low-voltage and high-voltage drive motor in the power tool.

FIG. 4 is a sectional view taken along line AA of FIG. 3;

FIG. 5 is a drive path block diagram of the electric power tool.

FIG. 6 is a cutaway side view of another example.

7A is a side view of an AC adapter pack, and FIG. 7B is a side view of a battery pack.

FIG. 8 is a schematic block diagram of the above.

FIG. 9 is a circuit block diagram of the above.

FIG. 10 is a perspective view of the same AC adapter pack.

FIG. 11 is an exploded perspective view of the same AC adapter pack.

FIG. 12 is a partial sectional view when the AC adapter pack is mounted.

FIG. 13 is a cutaway front view showing a power terminal and a corresponding terminal of the AC adapter pack of the above.

FIG. 14 is a side view showing a rotation range of a cord drawer of the AC adapter pack of the above.

FIGS. 15A and 15B are cross-sectional views of the AC adapter pack of the above.

FIG. 16 is a side view of the same.

FIGS. 17A to 17E are side views showing the relationship between the direction of the electric tool and the direction of the cord.

FIG. 18 is a perspective view of the switch with the one-side cover removed.

FIG. 19 is a side view showing the internal structure of the above switch.

FIG. 20 is a diagram illustrating the operation of the above switch.

FIG. 21 is an exploded perspective view of a rotation direction switching contact portion of the above switch.

FIG. 22 is a plan view of a rotation direction switching contact portion of the above switch.

FIG. 23 is a schematic circuit diagram of an example in which a winding is used as rotation speed detecting means.

FIG. 24 is a circuit diagram showing an example of wiring of a ground line.

FIG. 25 is a circuit diagram showing another example of the wiring of the ground line.

FIG. 26 is a circuit block diagram of another example.

FIG. 27 is a characteristic diagram showing characteristics of the overload protection device.

FIG. 28 is a circuit block diagram of still another example.

FIG. 29 is a cutaway side view of the same.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Apparatus main body 2 Cordless power supply device 3 Corded power supply device 5 DC motor 6 Means for converting current from an AC power supply to DC 7 Battery cell 8 Connection part 9 Rotor 10 Rotor winding 12 Brush 13 Commutator

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Wataru Murakita 1048 Kadoma Kadoma, Kadoma City, Osaka, Japan Matsushita Electric Works, Ltd. ) Inventor Koichi Hashimoto 1048 Kadoma Kadoma, Kadoma City, Osaka Pref. (72) Inventor Hiroshi Miyazaki 1048 Odaka Kadoma, Kadoma City, Osaka Pref. 1048 Oaza Kadoma Matsushita Electric Works Co., Ltd. (72) Inventor Masao Yamamoto 2026 Oshinohara, Yasu-cho, Yasu-gun, Shiga Prefecture Shiga Kobayashi Seiko Co., Ltd.F-term (reference) JJ03 JJ06 JJ14 LL14

Claims (23)

[Claims] 1. An apparatus main body comprising: a DC motor as a power unit, a cordless power supply device having a built-in battery cell, and a corded power supply device having a built-in means for converting a current from an AC power supply to a DC. A connection portion for electrically and mechanically connecting is provided, the supply voltage of the power supply device is made different, and the rotor winding of the DC motor is made into a multiple winding so as to be able to cope with different supply voltages, and the multiple winding is provided. A portable motor power unit comprising a plurality of combined brushes and commutators. 2. A multiplex winding of a rotor of a DC motor is designed so that, regardless of which of the plurality of power supply devices is selected, the obtained motor drive characteristics are the same. The portable motor power unit according to claim 1, characterized in that: 3. A power supply path from the cordless power supply to the low voltage winding of the DC motor, and a power supply path from the corded power supply to the high voltage winding of the DC motor. 3. The portable motor power unit according to claim 1, wherein the power unit is separated. 4. The DC motor is a double winding having a low voltage winding corresponding to DC 2.4V to 48V and a high voltage winding corresponding to DC 100V to 300V. The portable motor power unit according to any one of claims 1 to 3. 5. The cordless power supply device is a battery pack containing a chargeable / dischargeable secondary battery, and the corded power supply device is an AC adapter pack having substantially the same shape as the battery pack. The portable motor power unit according to any one of claims 1 to 4. 6. The battery pack includes a fitting portion inserted and connected to the connecting portion, and a connecting terminal provided in the fitting portion and connected to the low-voltage power receiving terminal portion. 6. The connector according to claim 5, further comprising: a fitting portion inserted into the portion; and a high voltage output connector provided adjacent to the fitting portion and connected to the high voltage power receiving terminal portion. Portable motor power unit. 7. The AC adapter pack includes a ground wire, and the high-voltage output connector includes a ground connection terminal connected to the motor via a high-voltage power receiving terminal portion. A portable motor power unit as described. 8. An AC adapter pack contains a board on which means for converting current from an AC power supply to DC is mounted, and the ground connection terminal and the ground wire are connected via a ground line formed on the board. 8. The portable motor power unit according to claim 7, wherein a noise removing capacitor is connected to the ground line. 9. The portable motor power according to claim 1, wherein a cord drawn from the power supply device with the cord has a drawer portion rotatable. apparatus. 10. The portable motor power unit according to claim 9, further comprising click generating means for generating clicks at a plurality of positions within a rotation range of the drawer. 11. The portable motor power unit according to claim 10, wherein the click generating means generates a click only at both ends of the rotation range of the drawer. 12. A rotation speed detecting means for detecting a motor rotation speed from an alternating potential generated in a rotor winding to which no voltage is applied among a plurality of rotor windings constituting a multiple winding of the rotor. The portable motor power unit according to any one of claims 1 to 11, further comprising: 13. An overload protection device for interrupting a circuit when an overload occurs in an electric power line from a corded power supply device to a DC motor. Portable motor power unit according to the paragraph. 14. The overload protection device is disposed inside a corded power supply device.
A portable motor power unit as described. 15. The portable motor power unit according to claim 13, wherein the overload protection device is arranged in a device main body of the power unit. 16. The portable motor power unit according to claim 13, wherein the overload protection device is a bimetallic thermostat that operates according to a rise in temperature. 17. The overload protection device according to claim 1, wherein the overload protection device is inserted in an AC circuit portion before full-wave rectification.
The portable motor power unit according to any one of items 3 to 16. 18. An overload protection device, which is a bimetallic thermostat that operates according to a rise in temperature, and further includes a second overload protection device that operates in a temperature range higher than the thermostat. Item 13-
18. The portable motor power unit according to any one of items 17. 19. The portable motor power unit according to claim 18, wherein the second overload protection device is a fuse that blows due to a rise in temperature and cuts off a circuit. 20. An electric power tool having a T-shaped housing including a cylindrical portion and a grip portion protruding from the middle of the cylindrical portion, wherein a DC motor and a switch for controlling power supply are provided in the housing. A cordless power supply device having a built-in battery cell, and a corded power supply device having a built-in means for converting current from an AC power supply to DC are selectively detachable, and the DC motor is It has a double winding and is equipped with a plurality of brushes and commutators matched to the double winding, and of the plurality of brushes connected to the double winding, power is supplied from the cordless power supply device. An electric tool, wherein a low-voltage driving brush receiving the power supply is disposed on a tool tip side, and a high-voltage driving brush receiving power supply from a corded power supply device is disposed on a tool rear end side. 21. The DC motor according to claim 2, further comprising a built-in cooling air discharge fan, wherein the fan is located near the low voltage driving brush.
0 power tool. 22. The power tool according to claim 20, wherein an overload protection device for interrupting a circuit when overloaded is provided in a grip portion of the housing. 23. The power tool according to claim 22, wherein the overload protection device is disposed near an electrical connection with the corded power supply device.