JP2007136607A - Power tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact power tool, having superior usability and reducing the total length of a housing by disposing a brush motor and a motor control electronic parts, in the direction orthogonal to the longitudinal direction of the housing. <P>SOLUTION: In this power tool, a built-in brush motor 2 mounted internally in a housing 1 is constructed by arraying a magnetic field part and a rectifying part 22 in the longitudinal direction E, F of the housing 1; the rectifying part 22 is provided with a plate-like brush holder 7 for positioning a brush 5; the end part away from the positioning part for the brush 5 in the brush holder 7 is cutout into a D-shape; a new space part 26 is formed, in a direction orthogonal to the longitudinal direction E, F of the housing 1 between the D-cut end part of the brush holder 7 and the inner surface of the housing 1; and the motor control electronic component 14 is disposed in the new space part 26. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a hand-held electric tool used for, for example, a drilling operation or a cutting operation, and more particularly to an electric tool in which a motor built in a housing is a built-in brush motor in which a motor case is omitted.

  Conventionally, a built-in brush motor in which a motor case is eliminated to reduce the weight of a train tool and a motor component is directly assembled to a housing is known (for example, see Patent Document 1).

  As shown in FIGS. 6 and 7, the conventional motor 2 is a brush motor in which a field unit 3 composed of a rotor 3 a and a field magnet 3 b and a rectification unit 22 composed of a brush 5 and a commutator 8 are separated. The rectifying unit 22 is disposed on the base end side F of the main body 1a of the housing 1 and the field unit 3 is disposed on the front end E of the main body 1a. In FIG. 6, 9 is a rechargeable battery and 21 is a chuck. Here, the rectifying unit 22 is provided with a circular brush holder 7 for positioning the brush 5, and the edge portion of the brush holder 7 is held by a pair of protrusions 25 formed on the housing 1. Thus, the brush holder 7 is held in the housing 1. Further, the housing 1 is divided into two parts for accommodating the interior parts, and these are screwed after the interior parts are assembled. The boss-like screwing part formed on the housing 1 is used for screwing. Among them, conventionally, the upper and lower screwing portions 11 and 12 at the rear portion of the main body portion 1 a should be arranged so as to protrude rearward (base end side F) from the brush holder 7 so as not to interfere with the circular brush holder 7. For this reason, there has been a problem that the entire length of the main body 1a of the housing 1 becomes long.

  Another conventional example is shown in FIG. In this conventional example, a motor control FET 14a (field effect transistor) and a heat dissipation plate 13 for releasing the heat of the FET 14a are arranged behind the motor 2 while adopting the same configuration as the motor 2 of FIGS. In this case as well, there is a problem that the entire length of the main body 1a of the housing 1 becomes long.

Still another conventional example is shown in FIGS. In the figure, 15 is a bearing, 17 is an FET lead, and 18 is a motor lead. The brush holder 7 of the electric power tool 30 is also circular as shown in FIG. 10, and the FET 14 a and the heat radiating plate 13 are arranged behind the brush holder 7 (base end side F) as shown in FIG. 9. Therefore, there exists a problem that the full length of the main-body part 1a of the housing 1 will become long. In some cases, the FET 14a and the heat radiating plate 13 are disposed in the switch case of the grip portion 1b in order to shorten the overall length. In this case, there is no flow of wind through the heat radiating plate 13, and the grip portion 1b is hot. Another problem arises.
JP 2003-025255 A

  The present invention has been invented in view of the above-described conventional problems, and allows the brush holder and the electronic component for motor control to be disposed compactly in a direction perpendicular to the length direction of the housing, whereby the housing It is an object of the present invention to provide a power tool that can shorten the overall length, is small, and has excellent usability.

  In order to solve the above-described problems, the present invention provides a power tool in which the motor 2 housed in the housing 1 is a built-in brush motor in which the motor case is omitted. The motor 2 includes a field magnet including a rotor and a field magnet. The plate 3 for positioning the brush 5 on the rectifying unit 22 is configured separately from the rectifying unit 22 composed of the brush 3 and the commutator 8 and arranged in the length direction E, F of the housing 1. The brush holder 7 is provided, and the end of the brush holder 7 away from the positioning portion of the brush 5 is cut into a D-cut shape so that the D-cut end of the brush holder 7 and the inner surface of the housing 1 are interposed. A new space portion 26 is formed in a direction orthogonal to the length directions E and F of the housing 1, and the motor control electronic component 14 is disposed in the new space portion 26.

  By adopting such a configuration, a new new space portion is formed in a direction orthogonal to the length directions E and F of the housing 1 between the end portion of the brush holder 7 cut into a D-cut shape and the inner surface of the housing 1. 26, and the motor control electronic component 14 can be accommodated using the new space 26, so that the brush holder 7 and the motor control electronic component 14 are connected in the longitudinal direction E, It becomes possible to arrange compactly in the direction orthogonal to F. In addition, since the end of the brush 5 away from the positioning portion is D-cut, the positioning function of the brush 5 by the brush holder 7 is exhibited as before, and the motor control electronic component 14 is mounted on the grip portion 1b side as in the prior art. There is no need to dispose it.

  The housing 1 houses a ventilation fan 4 that is rotated by the motor 2 and a heat radiating plate 13 for releasing heat from the motor control electronic component 14, and is located near the heat radiating plate 13 in the housing 1. It is preferable to form an air inlet 19 for introducing outside air. In this case, the electronic component 14 or the heat radiating plate 13 can be disposed in the passage of the cooling air by the ventilation fan 4, so that the cooling effect of the electronic component 14 is enhanced. Thus, the electronic component 14 is less susceptible to the heat generated by the motor 2.

  Further, an exhaust port 20 is provided in the housing 1 in the vicinity of the ventilation fan 4, and a ventilation hole 23 a for ventilating the ventilation fan 4 and the heat radiating plate 13 from the intake port 19 to the exhaust port 20 is provided in the rib 23. In this case, heat radiation from the heat radiating plate 13 to the exhaust port 20 becomes good through the ventilation holes 23a, the volume of the heat radiating plate 13 can be reduced, and the weight can be reduced.

  Further, the lower end portion 7a of the brush holder 7 is formed in a D-cut shape, and a lower portion for fixing the lower portions of the pair of half-cracked housings 1c and 1d to each other in a new space portion 26 formed below the brush holder 7. A side screwing portion 12 is preferably provided, and an upper screwing portion 11 for fixing the upper portions of the pair of half-cracked housings 1c and 1d to each other is provided near the upper end portion 7b of the brush holder 7. In this case, it is not necessary to place the upper and lower screwing portions 11 and 12 so as to protrude behind the brush holder 7, and the overall length of the housing 1 can be further shortened.

  In addition, it is preferable to contact the heat sink 13 with a bearing 15 that rotatably supports the drive shaft of the motor 2. In this case, the heat sink 13 for cooling the electronic component 14 is used to make the bearing 15. Thus, the life of the bearing 15 can be extended.

  In the present invention, the end of the brush holder is cut out in a D-cut shape to form a new space portion, and the motor control electronic components are disposed in the new space portion. The parts can be arranged compactly in the direction perpendicular to the length direction of the housing, and the overall length of the housing can be shortened, and the D-cut position of the brush holder is placed at the end portion away from the positioning portion of the brush. By setting, the positioning function of the brush by the brush holder is exhibited as usual, and furthermore, it is not necessary to arrange the motor control electronic parts on the grip part side as in the conventional case. As a result, the electric tool which is small and excellent in usability can be obtained.

  Hereinafter, the present invention will be described based on embodiments shown in the accompanying drawings.

  1 to 4 show a power tool 30 according to an embodiment of the present invention. As shown in FIGS. 2 and 3, the housing 1 of the electric tool 30 includes a horizontal cylindrical main body 1 a and a grip 1 b that hangs downward from the lower edge of the main body 1 a. A chuck 21, a drive unit (not shown), and a motor 2 are housed in the main body 1 a from the distal end E toward the proximal end F. The grip portion 1b of the housing 1 is provided with a switch (not shown) for turning on and off energization of the motor 2 that is electrically driven, and a rechargeable battery 9 is detachably provided at the lower end of the grip portion 1b. Here, the chuck 21 is provided with a chuck 21 on which a tool such as a drill or a screwdriver is mounted, and the drive unit is constituted by a speed reduction mechanism that transmits the rotational drive of the motor 2 to the chuck 21, and the motor 2 is an electric type. Electrical connection with the rechargeable battery 9 is made through a switch. In addition, the interior product housed in the housing 1 is positioned at a suitable position by a rib or the like formed on the inner surface of the housing 1 so as to divide the internal space of the housing 1. The switch for turning on / off the energization of the motor 2 is operated by a trigger 16 provided at a connecting portion between the main body 1a and the grip 1b of the housing 1.

  Here, the motor 2 is a built-in brush motor in which the motor case is omitted and the components of the motor 2 are housed in the housing 1, and the field unit 3 including the rotor 3a and the field magnet 3b (FIG. 7) and The rectifying unit 22 including the brush 5 and the commutator 8 is configured separately, and the field magnet unit 3 and the rectifying unit 22 are arranged in the length directions E and F of the housing 1. In this example, the rectifying unit 22 is disposed on the base end side F of the main body 1a of the housing 1, and the field unit 3 is disposed on the front end E of the main body 1a.

  The brush 5 is inserted into a brush case 6 provided in a brush holder 7 made of an insulating plate. In the example shown in FIG. 1, a pair of brush cases 6 are arranged in an upward V shape in the upper half of the brush holder 7, and the lower end portion 7 a of the brush holder 7 is formed in a D-cut shape. The outer shape is changed from a conventional circular shape to a D shape. The edge portion of the brush holder 7 on the upper end 7 b side is held by a pair of protrusions 25 (FIG. 4) formed on the housing 1. Further, by cutting the end portion of the brush holder 7 by D-cutting, a new space portion is formed in a direction orthogonal to the length directions E and F of the housing 1 between the D-cut end portion of the brush holder 7 and the inner surface of the housing 1. 26 is newly generated, and the electronic component 14 for motor control is disposed in the new space portion 26. Here, the FET 14a (field effect transistor) and the FET 14a are generated so as to be accommodated in a new new space 26 formed between the lower end 7a of the brush holder 7 and the inner peripheral surface of the main body 1a of the housing 1. A heat radiating plate 13 for removing the generated heat is provided. The FET 14a is a kind of semiconductor switching element that controls the current of the motor 2 and is electrically connected to other switch components via the FET lead wire 17 to adjust the current flowing from the rechargeable battery 9 to the motor 2. The rotational distance of the motor 2 is adjusted according to the pull-in amount of the trigger 16. Of course, the electronic component 14 for controlling the motor is not limited to the FET 14a, but includes a wide range of switching elements for controlling the rotational speed of the motor 2.

  A ventilation fan 4 is attached to the rotating portion (for example, drive shaft or rotor) of the motor 2, while an exhaust port 20, which is an exhaust air hole, is formed at the outer peripheral position of the ventilation fan 4 in the housing 1. In other portions, intake ports 19 (19a to 19c), which are air holes for intake, are formed. Then, as shown in FIG. 4, external air M is sucked from the intake port 19, heat of components (FET 14 a, heat sink 13, etc.) in the path is removed, and heated air N is discharged from the exhaust port 20. I have to. In this example, a rib 23 that partitions the rear of the ventilation fan 4 protrudes from the housing 1, and the air M sucked from the intake ports 19 a and 19 b passes through the circular ventilation holes 23 a provided in the ribs 23 to the exhaust port. I am heading to 20. Here, the heat radiating plate 13 has a fin shape, the air inlet 19a of the housing 1 is opened facing the outer peripheral portion of the heat radiating plate 13, and the air M sucked from the air inlet 19a is the fin of the heat radiating plate 13. The heat generation of the FET 14a can be efficiently removed through the recess 13a.

  The housing 1 is composed of a pair of half-cracked housings 1c and 1d (FIG. 4) for housing the interior parts, and a plurality of half-cracked housings 1c and 1d have a plurality of half-cracked housings 1c and 1d. Boss-shaped screwing portions 11 and 12 are projected. Of these screwing portions 11 and 12, the lower screwing portion 12 (FIG. 6) that is conventionally rearward of the brush holder 7 is replaced with the brush holder 7 and the heat radiating plate 13 shown in FIG. 3 in the present invention. In the present invention, the upper screwing portion 11 (FIG. 6), which is disposed below and located behind the brush holder 7 in the past, is positioned near the upper end portion 7b of the brush holder 7 (for example, the upper end portion 7b). It is arranged on the front side.

  Thus, a new new space 26 is formed in the direction perpendicular to the length directions E and F of the housing 1 between the lower end 7a of the brush holder 7 cut into a D-cut shape and the inner surface of the housing 1. The new space portion 26 is within the outer diameter range of the motor 2, and the brush holder is obtained by housing the FET 14a for motor control and the heat radiating plate 13 for releasing the heat in the new space portion 26. 7, the FET 14 a, and the heat radiating plate 13 can be compactly arranged in the direction orthogonal to the length directions E and F of the housing 1, so that the overall length of the main body 1 a of the housing 1 can be shortened. In addition, since the end of the brush 5 away from the positioning portion is D-cut, the positioning function of the brush 5 by the brush holder 7 is exhibited as before, and the FET 14a needs to be disposed on the grip portion 1b side as in the prior art. Therefore, there is an advantage that the grip portion 1b is not heated and the usability is improved.

  Further, in this example, an exhaust port 20 is provided in the housing 1 in the vicinity of the ventilation fan 4, and a ventilation hole 23 a for ventilating the ventilation fan 4 and the heat radiating plate 13 from the intake port 19 to the exhaust port 20 is provided in the rib 23. Since it is provided, as the heat radiation from the heat radiating plate 13 to the exhaust port 20 is further improved, the volume of the heat radiating plate 13 can be kept small, which contributes to downsizing. In addition, a lower screwing portion 12 for fixing the lower portions of the pair of half-cracked housings 1c and 1d to each other is disposed in a new space portion 26 formed below the brush holder 7, and the upper end portion 7b of the brush holder 7 is disposed. Since the upper screwing portions 11 for fixing the upper portions of the half-cracked housings 1c and 1d to each other are disposed in the vicinity, the upper and lower screwing bosses are projected behind the brush holder 7 as in the prior art. Compared with the case where it arrange | positions, there exists an advantage which can further shorten the full length of the main-body part 1a of the housing 1 further.

  Further, in this example, the ventilation fan 4 is attached to the rotating part of the motor 2, the fin-like heat radiation plate 13 for releasing heat is attached to the FET 14a, and the air inlet 19 is provided in the housing 1 in the vicinity of the heat radiation plate 13. Thus, the FET 14a or the heat radiating plate 13 can be arranged in the passage of the cooling air by the ventilation fan 4, and the cooling effect of the FET 14a can be enhanced. There are also advantages that can be made.

  As another embodiment of the present invention, as shown in FIG. 5, a bearing 15 that rotatably supports the drive shaft of the motor 2 is provided on the inner surface of the housing 1, and an end surface portion 13a of the heat sink 13 of the FET 14a is provided. It is desirable to contact the outer ring of the bearing 15. Other configurations are the same as those in FIG. In this example, since the heat generated in the bearing 15 can be removed by using the heat radiating plate 13 for releasing the heat of the FET 14a, there is an advantage that the life of the bearing 15 can be greatly extended.

  In addition, in the said embodiment, although the position formed in D cut shape of the brush holder 7 was set to the lower end part 7a of the brush holder 7, not only this but the side edge or upper end part 7b of the brush holder 7 is D cut shape, for example May be formed.

FIG. 6 is a cross-sectional view taken along the line AA in FIG. 3 and the line BB in FIG. 5, showing a D-cut brush holder used in an embodiment of the present invention. It is a side view of the electric tool by which the motor same as the above was built in the housing. It is the side view which fractured partially the electric tool same as the above. It is the perspective view which fractured | ruptured the vicinity of the motor vicinity same as the above. It is the side view which fractured | ruptured partially of other embodiment of this invention. It is explanatory drawing of the internal structure of the electric tool of a prior art example. It is description of the internal structure of the motor of a prior art example. It is explanatory drawing of the internal structure of the electric tool of another prior art example. It is explanatory drawing of the internal structure of the electric tool of another prior art example. It is sectional drawing which shows the conventional circular brush holder and follows CC line of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Housing 1a Body part 1c, 1d Half-splitting housing 2 Motor 3 Field magnet part 4 Ventilation fan 5 Brush 7 Brush holder 7a Lower end part 8 Commutator 11, 12 Screwing part 13 Heat sink 14 Electronic component 15 Bearing 19 Inlet 20 Exhaust Port 22 Rectifier 23 Rib 23a Ventilation hole 26 New space

Claims (6)

  In the electric tool in which the motor incorporated in the housing is a built-in brush motor in which the motor case is omitted, the motor includes a field portion composed of a rotor and a field magnet and a rectification portion composed of a brush and a commutator. A plate-shaped brush holder for positioning the brush is provided in the rectifying portion, and an end portion of the brush holder away from the brush positioning portion is formed in a D-cut shape. By forming the notch, a new space is formed in the direction perpendicular to the length direction of the housing between the D-cut end of the brush holder and the inner surface of the housing, and an electronic component for motor control in the new space An electric tool characterized by comprising:   Inside the housing, a ventilation fan rotated by a motor and a heat radiating plate for releasing heat of electronic components for motor control were housed, and an air inlet for introducing outside air was formed at a position near the heat radiating plate in the housing. The power tool according to claim 1.   3. The electric motor according to claim 2, wherein an exhaust port is provided near the ventilation fan in the housing, and a ventilation hole for ventilating from the intake port to the exhaust port is provided in a rib partitioning the ventilation fan and the heat radiating plate. tool.   The lower end portion of the brush holder is formed in a D-cut shape, and a lower screwing portion for fixing the lower portions of the pair of half-cracked housings to each other is provided in a new space portion formed below the brush holder. The electric tool according to any one of claims 1 to 3, wherein   5. The electric power tool according to claim 1, wherein an upper screwing portion for fixing the upper portions of the pair of half-cracked housings to each other is disposed in the vicinity of the upper end portion of the brush holder. . 4. The electric tool according to claim 2, wherein a bearing for rotatably supporting a motor drive shaft is brought into contact with the heat radiating plate.

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