JP2010173042A - Power tool - Google Patents

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Publication number
JP2010173042A
JP2010173042A JP2009020452A JP2009020452A JP2010173042A JP 2010173042 A JP2010173042 A JP 2010173042A JP 2009020452 A JP2009020452 A JP 2009020452A JP 2009020452 A JP2009020452 A JP 2009020452A JP 2010173042 A JP2010173042 A JP 2010173042A
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Japan
Prior art keywords
housing
motor
power supply
substrate
power
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Granted
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JP2009020452A
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Japanese (ja)
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JP5424018B2 (en
Inventor
Nobuhiro Takano
Hideyuki Tanimoto
英之 谷本
信宏 高野
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Hitachi Koki Co Ltd
日立工機株式会社
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Application filed by Hitachi Koki Co Ltd, 日立工機株式会社 filed Critical Hitachi Koki Co Ltd
Priority to JP2009020452A priority Critical patent/JP5424018B2/en
Priority claimed from CN201080002583.1A external-priority patent/CN102149515B/en
Publication of JP2010173042A publication Critical patent/JP2010173042A/en
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Publication of JP5424018B2 publication Critical patent/JP5424018B2/en
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B25HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25FCOMBINATION OR MULTI-PURPOSE TOOLS NOT OTHERWISE PROVIDED FOR; DETAILS OR COMPONENTS OF PORTABLE POWER-DRIVEN TOOLS NOT PARTICULARLY RELATED TO THE OPERATIONS PERFORMED AND NOT OTHERWISE PROVIDED FOR
    • B25F5/00Details or components of portable power-driven tools not particularly related to the operations performed and not otherwise provided for
    • B25F5/008Cooling means

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-output power tool that is improved in workability by reducing a size of a housing. <P>SOLUTION: A housing 2 comprises an almost cylindrical grip 21 and a gear cover 22 connected to the front of the grip 21. The grip 21 stores a motor 3, a motor drive circuit 8 for controlling the motor 3, and a fan 6. The motor drive circuit 8 includes a smoothing capacitor 81, a power supply substrate 82, a control substrate 83, and an FET substrate 84. The power supply substrate 82 is mounted with a power supply 85 connected to a power supply line 7 via the smoothing capacitor 81 so as to rectify power supplied from an unillustrated external power supply. The control substrate 83 is mounted with a control part 86 for converting the power rectified by the power supply 85 into an inverter signal. The FET substrate 84 is mounted with a FET 87 for driving the motor 3 on the basis of the inverter signal from the control substrate 83. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electric tool using a brushless motor.

  A brushless motor capable of realizing high efficiency can also be used as a drive source of an electric tool. However, a brushless motor requires a motor drive circuit that is not required for a brushed motor. In an electric tool provided with a brushless motor, the motor drive circuit is housed in a power supply box separately provided between the electric tool and an external power supply (for example, Patent Document 1). In such a power tool, when a plurality of power tools are connected to the same external power source, the power box moves as the operator moves, and the power boxes collide with each other and are damaged. There was a problem.

  Therefore, it has been proposed to accommodate the motor drive circuit in the electric tool. For example, Patent Documents 2, 3 and 4 describe techniques relating to the arrangement of a motor drive circuit board in the housing of an electric tool. Specifically, Patent Document 2 discloses a cordless impact driver in which an electric circuit board that is a part of a motor driving circuit is provided between a grip portion and a driving battery. Patent Document 3 discloses a cordless impact driver that houses a control board, which is a part of a motor drive circuit, in a handle portion. Furthermore, Patent Document 4 discloses a cordless hammer drill that accommodates an FET substrate that is a part of a motor drive circuit substrate in a space defined above a housing portion of a brushless motor.

Special table 2008-504136 published (Figure 1) JP 2007-283447 A JP 2006-297532 A JP 2008-173716 A

  However, the arrangement of the motor drive circuit described in Patent Documents 2, 3 and 4 is applied to an electric tool (for example, a disk glider) used by an operator holding the motor housing part for the following reason. Have difficulty. First, in the electric tools described in Patent Documents 2, 3, and 4, since each substrate is arranged so that a part of each substrate is located radially outside the outer diameter of the brushless motor, the electric tool such as a disc grinder is used. When applied, it is necessary to increase the diameter of the motor housing portion. When the diameter of the motor housing portion is increased, it becomes difficult for an operator to grip the motor housing portion, resulting in a problem that workability is reduced.

  The motor drive circuit has a plurality of switching elements such as field effect transistors (hereinafter abbreviated as FETs). Since an operation current flows through the FET and a switching operation is performed at a high speed, the FET generates a larger amount of heat than other electronic components. For this reason, when the motor drive circuit is housed in the housing of the electric tool, it is particularly required to consider the cooling of the FET and to efficiently arrange the motor drive circuit board. In particular, in a power tool such as a disc grinder that has a higher output than other power tools, it is necessary to use an AC power source instead of a battery power source, and thus a large-sized FET is used. Therefore, when six FETs are arranged on the circumference as in Patent Document 4, there is a problem that the diameter of the circumference in which the FETs are arranged becomes large, resulting in an increase in the size of the housing.

  Therefore, an object of the present invention is to provide a high-powered electric tool while reducing the size of the housing to improve workability.

  To achieve the above object, the present invention provides a housing having a substantially cylindrical gripping portion, a brushless motor housed in the gripping portion, and a motor housed in the gripping portion and driving the brushless motor. An electric power tool comprising a drive circuit.

  The present invention also includes a housing having a substantially cylindrical gripping portion, a drive shaft, a brushless motor housed in the gripping portion, and a motor housed in the gripping portion for driving the brushless motor. There is provided an electric tool comprising: a drive circuit; and a switch that protrudes in the axial direction of the grip portion from the other end with respect to one end of the grip portion.

  The motor drive circuit preferably has a plurality of substrates.

  In addition, it is preferable that at least one of the plurality of substrates is arranged so that a mounting surface is substantially perpendicular to an axial direction of the grip portion.

  Moreover, it is preferable that the plurality of substrates are arranged so that the mounting surface of each substrate is substantially perpendicular to the axial direction of the grip portion.

  Moreover, it is preferable that each board | substrate of the said several board | substrate is a shape substantially the same as the external shape of the said brushless motor.

  Moreover, it is preferable that each board | substrate of these board | substrates is substantially circular shape, and is arrange | positioned so that it may be located substantially concentrically with the said brushless motor.

  In addition, it is preferable that at least a part of each of the plurality of substrates overlaps the brushless motor in the radial direction of the grip portion.

  Furthermore, a tip tool that is detachably attached to one end side of the housing, a gear portion that transmits a driving force from the brushless motor to the tip tool, and provided on the other end side of the housing, and receives power from an external power source. A power line for supplying, and arranged from the other end side to the one end side in the order of the power line, the motor drive circuit, the brushless motor, the gear unit, and the tip tool. preferable.

  Furthermore, a tip tool provided on one end side of the housing, and a power supply line provided on the other end side of the housing for supplying power from an external power source, the motor drive circuit is connected to the power supply line. A rectifier circuit that rectifies the power supplied from the external power supply, an inverter circuit that converts the rectified power into an inverter signal, and a switching element substrate that includes a switching element that drives a motor based on the inverter signal; It is preferable that the power supply line, the rectifier circuit, the inverter circuit, the switching element substrate, and the brushless motor are arranged in this order from the other end side to the one end side.

  Furthermore, a tip tool provided on one end side of the housing and a power supply line provided on the other end side of the housing for supplying electric power from an external power source, an air inflow into the other end side of the housing A hole is formed, an air discharge hole is formed on one end side of the housing, and a ventilation path is formed in the housing for communicating the air inflow hole and the air discharge hole. A switching element substrate having a mounting surface on which a switching element is mounted, wherein the switching element has a substantially rectangular parallelepiped shape, and the widest surface of the substantially rectangular parallelepiped shape is directed from the other end side to the one end side of the housing It is preferable that it is arrange | positioned so that it may become substantially parallel.

  Moreover, it is preferable that the housing has a guide portion located in the vicinity of the switching element, and the ventilation path includes a space formed between the guide portion and the switching element.

  Moreover, it is preferable that the switching element substrate has a through hole connected to the ventilation path.

  According to the electric tool of the first aspect, since all of the motor drive circuit for driving the brushless motor is accommodated in the grip portion, it is necessary to provide an external power supply box between the electric tool and the external power source. There is no. Therefore, even if a plurality of power tools are connected to the same external power source, there is no possibility that the power supply boxes collide and are damaged. Further, when the operator uses the electric tool, the power supply box does not get in the way and the workability is improved. In addition, since the grip portion is formed in a substantially cylindrical shape, the operator can easily grip the grip portion and workability is improved.

  According to the electric tool of the second aspect, since all of the motor drive circuit for driving the brushless motor is accommodated in the grip portion, it is necessary to provide an external power supply box between the electric tool and the external power source. There is no. Therefore, even if a plurality of power tools are connected to the same external power source, there is no possibility that the power supply boxes collide and are damaged. Further, when the operator uses the electric tool, the power supply box does not get in the way and the workability is improved. In addition, since the grip portion is formed in a substantially cylindrical shape, the operator can easily grip the grip portion and workability is improved. Further, the switch protrudes from the other end with respect to one end of the gripping portion and extends in the axial direction of the gripping portion. That is, the switch is not provided on the radially outer side of the gripping portion. Therefore, when the operator grips the grip portion, it is possible to prevent the switch from getting in the way or pressing the switch by mistake.

  According to the third aspect of the present invention, since the motor drive circuit has a plurality of substrates, the substrate related to the motor drive circuit in the gripping portion is compared with the case where the motor drive circuit is provided on a single substrate. The degree of freedom of arrangement is improved. Therefore, the board | substrate regarding a motor drive circuit can be arrange | positioned efficiently, and it can prevent that a dead space is defined in a housing.

  According to the power tool of claim 4, at least one of the plurality of substrates is disposed such that the mounting surface is substantially perpendicular to the axial direction of the grip portion, and therefore the motor drive circuit is disposed. Therefore, it is possible to reduce the length of the gripping portion necessary for the axial direction. Therefore, a compact and good workability electric tool can be provided.

  According to the electric power tool of claim 5, each of the plurality of substrates is disposed so that the mounting surface is substantially perpendicular to the axial direction of the housing, and therefore is necessary for disposing the motor drive circuit. The length of the grip portion in the axial direction can be reduced. Therefore, a compact and good workability electric tool can be provided.

  According to the electric tool of claim 6, by forming each substrate of the plurality of substrates substantially in the same shape as the outer diameter of the brushless motor, the gripping portion is not defined in the gripping portion. The diameter can be reduced. Therefore, it becomes easier to grip the gripping part, and the workability of the operator is improved.

  According to the electric tool of claim 7, by arranging each substrate of the plurality of substrates so as to be positioned substantially concentrically with the brushless motor, it is possible to grasp the waste space without defining a useless space in the grasping portion. The diameter of the part can be reduced. Therefore, it becomes easier to grip the gripping part, and the workability of the operator is improved.

  According to the power tool of claim 8, each substrate of the plurality of substrates is arranged so that at least a part thereof overlaps with the brushless motor in the radial direction of the gripping portion, thereby preventing the gripping portion from increasing in diameter. can do.

  According to the electric tool of the ninth aspect, the center of gravity of the electric tool can be positioned on one end side by arranging the heavy-weight tip tool and the gear portion on one end side. Therefore, compared with the case where the center of gravity of the electric power tool is located on the other end side, the operator can easily balance and the workability is improved.

  According to the electric tool of the tenth aspect, since the power supply line, the rectifier circuit, the inverter circuit, the switching board, and the brushless motor are arranged in this order from the other end side to the one end side, the same as the power supply direction. In addition, the wiring can be routed along the direction from the power line to the brushless motor. Therefore, the wiring can be routed without waste, and a compact and good power tool can be provided.

  According to the electric tool of the eleventh aspect, the cooling air taken from the air inlet hole flows in the air passage from the air inlet hole toward the air outlet hole. That is, the cooling air generally flows along the direction from the other end side to the one end side. Furthermore, since the widest surface of the switching elements is arranged so as to be substantially parallel to the direction from the other end side to the one end side, the cooling air flows along the widest surface of the switching elements. Therefore, the cooling efficiency of the switching element is improved, and a power tool with higher output can be provided.

  According to the electric tool of claim 12, since the guide portion is provided in the vicinity of the switching element in the housing and includes a space formed between the guide portion and the switching element as a part of the ventilation path, The cooling air can be concentrated in the vicinity of the switching element, the cooling efficiency of the switching element can be improved, and a higher-power electric tool can be provided.

  According to the power tool of the thirteenth aspect, since the through hole is formed in the switching element substrate, the cooling air flows from the ventilation path to the switching element through the through hole, so that the cooling efficiency of the switching element is improved. It is possible to provide a power tool with higher output.

1 is a cross-sectional view showing a disc grinder according to a first embodiment of the present invention. 1 is a perspective view showing a motor drive circuit of a disc grinder according to a first embodiment of the present invention. Sectional drawing which shows the disk grinder which concerns on the 2nd Embodiment of this invention. The perspective view which shows the motor drive circuit of the disk grinder which concerns on the 2nd Embodiment of this invention. Sectional drawing which shows the disc grinder which concerns on the 3rd Embodiment of this invention. The perspective view which shows the motor drive circuit of the disk grinder which concerns on the 3rd Embodiment of this invention. The perspective view seen from another angle which shows the motor drive circuit of the disc grinder which concerns on the 3rd Embodiment of this invention. Sectional drawing which concerns on the modification of the disc grinder which concerns on the 3rd Embodiment of this invention. Sectional drawing which concerns on another modification of the disk grinder which concerns on embodiment of this invention. The perspective view which shows the motor drive circuit of the disk grinder which concerns on the modification shown in FIG.

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

  Hereinafter, the power tool according to the first embodiment of the present invention will be described with reference to FIG. 1 and FIG. A disc grinder 1 shown in FIG. 1 includes a housing 2 that houses a motor 3, a gear portion 4 that is rotationally driven by the motor 3, a grinding wheel 5 that obtains rotational force from the gear portion 4, a fan 6, and a power source. The line 7 is mainly provided. Hereinafter, the disc grinder 1 will be described with the grinding wheel 5 side as the front and the power line 7 side as the rear.

  The housing 2 includes a substantially cylindrical gripping portion 21 and a gear cover 22 connected to the front of the gripping portion 21. The gripping part 21 accommodates the motor 3, the motor drive circuit 8 that controls the motor 3, and the fan 6. The grip part 21 is formed in a substantially cylindrical shape by combining two semi-cylindrical members that are substantially surface objects, and fixes the motor 3 and the motor drive circuit 8. An air inflow hole 2 a for allowing air to flow in from the outside of the housing 2 is formed in the rear portion of the grip portion 21. Furthermore, the guide part 23 which has 23 A of opposing surfaces which oppose the cooling surface 87B of FET87 mentioned later is provided in 21 A of inner peripheral surfaces of the holding part 21. As shown in FIG. In the housing 2, an air passage 2 c is defined which communicates between an air inflow hole 2 a formed in the grip portion 21 and an air exhaust hole 2 b formed in a gear cover 22 described later. Specifically, the air inflow hole 2 a and the air discharge hole 2 b are formed of a first air path 2 d defined between the inner peripheral surface 21 A (including the facing surface 23 A) of the grip portion 21 and the motor drive circuit 8. The second air passage 2e is defined between the outer peripheral surface 3A of the motor 3 and the inner peripheral surface 21A of the grip portion 21. In addition, a power line 7 for supplying electric power from an external power source (not shown) to the motor 3 via the motor driving circuit 8 and a control for driving and stopping the motor 3 are provided at the rear portion of the gripping portion 21. A switch 9 is provided. The switch 9 is provided so as to protrude from the rear end 21 </ b> B of the grip 21 and extend in the axial direction of the grip 21. The power line 7 and the switch 9 are fixed by the grip portion 21 by combining two semi-cylindrical members forming the grip portion 21.

  The motor 3 is a brushless motor of an inner rotor type having a well-known configuration having a substantially cylindrical outer shape and including a stator, a coil, a rotor, and a drive shaft 31 that rotates integrally with the rotor. A part of the outer peripheral surface 3A of the motor 3 is supported by the inner peripheral surface 21A of the grip portion 21, and a space 2e that is a part of the air passage 2c is formed between the remaining portion of the outer peripheral surface 3A and the inner peripheral surface 21A. It is defined. The drive shaft 31 is rotatably supported by a bearing 32 provided in the grip portion 21 and a bearing 33 provided on the gear cover 22 described later. A fan 6 is fixed to the front side of the drive shaft 31. When the motor 3 is driven, the fan 6 rotates integrally with the drive shaft 31, sucks air outside the housing 2 from the air inflow hole 2a, generates cooling air in the housing 2, and the air path as described above. The cooling air is discharged to the outside through the air discharge hole 2b through 2c. That is, the cooling air flows from the rear to the front of the housing 2 along the air path 2c.

  The gear cover 22 is formed with an air discharge hole 2b for discharging cooling air. A part of the gear cover 22 covers half of the outer periphery of the grinding wheel 5. The gear portion 4 accommodated in the gear cover 22 has a known configuration including a pinion gear and the like, and has an output shaft 41. The gear unit 4 transmits the rotational force input from the drive shaft 31 of the motor 3 to the output shaft 41 and transmits it to the grinding wheel 5 for grinding. The output shaft 41 extends substantially at right angles to the drive shaft 31 and is rotatably supported integrally with the grinding wheel 5. The grinding wheel 5 is detachably attached to the gear cover 22.

  Next, the motor drive circuit 8 will be described. As shown in FIGS. 1 and 2, the motor drive circuit 8 includes a smoothing capacitor 81 (FIG. 1), a power supply substrate 82, a control substrate 83, and an FET substrate 84. A smoothing capacitor 81 (FIG. 1), a power supply substrate 82, a control substrate 83, and an FET substrate 84 are arranged in this order from the rear to the front of the housing 2 (gripping portion 21).

  The smoothing capacitor 81 is a capacitor for smoothing a power supply voltage supplied from an external power supply (not shown) through the power supply line 7, and is electrically connected to the power supply substrate 82 by a wiring (not shown).

  The power supply substrate 82 is formed in a substantially circular shape that is substantially the same as the outer shape of the motor 3. Specifically, the power supply substrate 82 is formed in a substantially circular shape having a diameter slightly smaller than the outer diameter of the motor 3. The power supply board 82 is electrically connected to the switch 9 by wiring (not shown). On the mounting surface 82A of the power supply substrate 82, a power supply unit 85 is mounted which is connected to the power supply line 7 via the smoothing capacitor 81 and rectifies power supplied from an external power supply (not shown). For example, when the power supply voltage smoothed by the smoothing capacitor 81 is 100 V AC, the power supply unit 85 converts the smoothed voltage to about 18 V and rectifies it. The power supply board 82 is positioned substantially concentrically with the motor 3 and is disposed so that the mounting surface 82A is substantially perpendicular to the axial direction of the grip portion 21 (axial direction of the drive shaft 31 of the motor 3). Yes.

  The control board 83 is formed in a substantially circular shape substantially the same as the outer shape of the motor 3 and the power supply board 82, and has a mounting surface 83A on which the control unit 86 is mounted. Specifically, the power supply board 83 is formed in a substantially circular shape having a diameter slightly smaller than the outer diameter of the motor 3. The control board 83 is electrically connected to the power supply board 82 by wiring (not shown). The control unit 85 converts the power rectified by the power supply unit 85 into an inverter signal. The control board 83 is positioned substantially concentrically with the motor 3 and the power supply board 82, and is disposed so that the mounting surface 83 </ b> A is substantially perpendicular to the axial direction of the grip portion 21.

  The FET substrate 84 is formed in a substantially square shape and has mounting surfaces 84A and 84B on which the FET 87 is mounted. The FET substrate 84 is disposed such that two mounting surfaces 84 </ b> A are substantially parallel to the axial direction of the housing 2. The FET substrate 84 is electrically connected to the control substrate 83 by wiring (not shown). Three FETs 87 are arranged in a row on the mounting surface 84A. The FET 87 is electrically connected to the coil of the motor 3 through a wiring (not shown), and drives the motor 3 based on an inverter signal from the control board 83. Each FET 87 has a substantially rectangular parallelepiped shape, and has an installation surface 87A (FIG. 1) in contact with the mounting surface 84A and a cooling surface 87B facing the installation surface 87A (FIG. 1). The installation surface 87 </ b> A (FIG. 1) and the cooling surface 87 </ b> B are surfaces having the largest area among the six surfaces of the FET 87 and extend substantially parallel to the direction from the rear to the front of the housing 2. The FET substrate 84 is disposed such that the cooling surface 87B is substantially parallel to the facing surface 23A of the guide portion 23. Further, the FET substrate 84 has substantially the same length as the outer diameter of the motor 3.

  Further, the power supply substrate 82, the control substrate 83, and the FET substrate 84 of the motor drive circuit 8 are located within (overlapping) the outer diameter of the motor 3 in the radial direction of the grip portion 21 when viewed from the axial direction of the grip portion 21. ) Is arranged as follows. The power supply substrate 82, the control substrate 83, and the FET substrate 84 are fixed by the grip portion 21 by combining two semi-cylindrical members forming the grip portion 21, and are arranged as described above.

  Next, the operation of the disc grinder 1 will be described. When the operator turns on the switch 9, the motor 3 rotates and transmits this rotational force to the gear unit 4, and finally the grinding wheel 5 fixed to the rotating shaft 41 of the gear unit 4 rotates. On the other hand, when the operator turns off the switch 9, the motor 3 stops and the rotation of the grinding wheel 5 is finished.

  According to the disc grinder 1 described above, since all of the motor drive circuit 8 for driving the motor 3 is accommodated in the grip portion 21, it is necessary to provide an external power supply box between the disc grinder 1 and an external power source. There is no. Therefore, even if a plurality of disc grinders 1 are connected to the same external power source, there is no possibility that the power supply boxes collide and are damaged. Further, when the worker uses the disc grinder 1, the power supply box does not get in the way, and the workability is improved. Further, since the grip portion 21 is formed in a substantially cylindrical shape, an operator can easily grip the grip portion 21 and workability is improved.

  In addition, since the motor drive circuit 8 includes a plurality of substrates (power supply substrate 82, control substrate 83, and FET substrate 84), the motor drive circuit 8 in the grip portion 21 is compared with the case where the motor drive circuit is provided on one substrate. The degree of freedom in the arrangement of the substrate related to the motor drive circuit 8 is improved. Therefore, the board | substrate regarding the motor drive circuit 8 can be arrange | positioned efficiently, and it can prevent that a dead space is made in the holding part 21. FIG.

  Further, since the mounting surfaces 82A and 83A of the power supply board 82 and the control board 83 are arranged so as to be substantially perpendicular to the axial center direction of the holding part 21, the axis of the holding part 21 necessary for arranging the motor drive circuit 8 is used. The length in the direction of the heart can be reduced. Therefore, it is possible to provide a compact disc grinder with good workability.

  Further, the switch 9 protrudes from the rear end portion of the grip portion 21 and extends in the axial direction of the grip portion 21. That is, the switch 9 is not provided on the radially outer side of the grip portion 21. Therefore, it is possible to prevent the switch 9 from being in the way when the operator grips the grip portion 21 or pressing the switch 9 by mistake.

  Further, each substrate of the motor drive circuit 8 is disposed so that at least a part thereof overlaps the motor 3 in the radial direction of the gripping portion 21 when viewed from the axial direction of the gripping portion 21. An increase in the diameter can be prevented.

  In addition, the center of gravity of the disc grinder 1 can be positioned forward by arranging the grinding wheel 5 and the gear portion 4 that are heavy in weight. Therefore, compared with the case where the center of gravity of the disc grinder 1 is located rearward, the operator can easily balance and the workability is improved.

  Further, since the power supply line 7, the power supply board 82, the control board 83, the FET board 84, and the motor 3 are arranged in this order from the rear to the front, the power supply line 7 is connected to the motor 3 in the same manner as the power supply direction. Wiring can be routed along the direction toward Therefore, the wiring can be routed without waste, and a compact and good workability disc grinder can be provided.

  Moreover, the cooling air taken in from the air inflow hole 2a flows in the air passage 2c from the air inflow hole 2a toward the air discharge hole 2b. That is, the cooling air generally flows along the direction from the rear to the front. In the present embodiment, the cooling surface 87B of the FET 87 is disposed so as to be substantially parallel to the axial direction of the grip portion 21 (the direction from the rear to the front of the housing 2). Flowing along. Therefore, the cooling efficiency of the FET 87 is improved, and a higher output disc grinder can be provided.

  Further, the guide portion 23 is provided in the vicinity of the FET 87 in the housing 2, and the first air passage 2 d (the air passage 2 c) includes a space formed between the guide portion 23 and the FET 87. The cooling air can be concentrated, the cooling efficiency of the FET 87 can be improved, and a higher output disc grinder can be provided.

  Next, a disc grinder 101 according to the second embodiment will be described with reference to FIGS. The disc grinder 101 has the same configuration as the disc grinder 1 except that a motor drive circuit 108 is provided instead of the motor drive circuit 8.

  As shown in FIGS. 3 and 4, the motor drive circuit 108 includes a power supply substrate 82 on which the power supply unit 85 is mounted, a control substrate 83 on which the control unit 86 is mounted, and an FET substrate 184 on which the FET 187 is mounted. have. The FET substrate 184 is electrically connected to the control substrate 83 by wiring (not shown). The FET substrate 184 is formed in a substantially square shape, and has a mounting surface 184A on which six FETs 187 are mounted. The FET substrate 184 is installed so that the mounting surface 184A is substantially perpendicular to the mounting surfaces 82A and 83A of the power supply substrate 82 and the control substrate 83 (substantially parallel to the axial direction of the grip portion 21). The FET 187 is electrically connected to the coil of the motor 3 through a wiring (not shown), and drives the motor 3 based on an inverter signal from the control unit 86. Each FET 187 has a substantially rectangular parallelepiped shape, and has an installation surface 187A (FIG. 3) in contact with the mounting surface 184A, and two cooling surfaces 187B, which are the largest surfaces among the six surfaces of the FET 187. The cooling surface 187 </ b> B extends substantially parallel to the direction from the rear to the front of the housing 2. The power supply substrate 82, the control substrate 83, and the FET substrate 184 are fixed by the grip portion 21 by combining two semi-cylindrical members forming the grip portion 21, and are arranged as described above. According to such a disc grinder 101, the same effect as the disc grinder 1 can be obtained.

  Next, a disc grinder 201 according to a third embodiment will be described with reference to FIGS. The disc grinder 201 has the same configuration as the disc grinder 1 except that it includes a housing 202 instead of the housing 2 and a motor drive circuit 208 instead of the motor drive circuit 8. The housing 202 has a gripping part 221, and the gripping part 221 is the same as the gripping part 21 except that the guide part 23 is not provided on the inner peripheral surface 221A.

  5 to 7, the motor drive circuit 208 includes a power supply substrate 82 on which the power supply unit 85 is mounted, a control substrate 83 on which the control unit 86 is mounted, and an FET substrate 284 on which the FET 287 is mounted. have. The FET substrate 284 is electrically connected to the control substrate 83 by wiring (not shown). Similar to the power supply substrate 82 and the control substrate 83, the FET substrate 284 is formed in a substantially circular shape substantially the same as the outer shape of the motor 3, and has a mounting surface 284A on which six FETs 287 are mounted. The FET substrate 284 is positioned substantially concentrically with the motor 3 and is disposed so that the mounting surface 284A is substantially perpendicular to the axial center direction of the grip portion 221 (axial center direction of the drive shaft 31 of the motor 3). Yes. The FET 287 is electrically connected to the coil of the motor 3 through a wiring (not shown), and drives the motor 3 based on an inverter signal from the control unit 86. Each FET 287 has a substantially rectangular parallelepiped shape, and has an installation surface 287A (FIG. 1) in contact with the mounting surface 284A, and a cooling surface 287B which is the largest surface among the six surfaces of the FET 287. Two rows of three FETs 287 are arranged in one row on the mounting surface 284A. The FETs 287 located in the same row are mounted such that the cooling surfaces 287B face each other. The cooling surface 287B of each FET 287 extends substantially parallel to the direction from the rear to the front of the housing 2 (the axial direction of the grip portion 221). The power supply substrate 82, the control substrate 83, and the FET substrate 284 are fixed by the grip portion 221 by combining two semicylindrical members forming the grip portion 221, and are arranged as described above. The mounting surface 284A has six through holes 284a that are opened in a direction substantially parallel to the cooling surface 287B of each FET 287 and connected to the air passage 2c (2d).

  According to the disk grinder 201, all the mounting surfaces 82A, 83A, and 284A of the motor drive circuit 208 (the power supply substrate 82, the control substrate 83, and the FET substrate 284) are substantially perpendicular to the axial direction of the grip portion 221. Therefore, the length in the axial direction of the grip portion 221 necessary for arranging the motor drive circuit 208 can be reduced. Therefore, it is possible to provide a compact disc grinder with good workability.

  Furthermore, since all the substrates (the power supply substrate 82, the control substrate 83, and the FET substrate 284) of the motor drive circuit 208 have substantially the same shape as the outer shape of the motor 3, a useless space is defined in the grip portion 221. The diameter of the grip portion 221 can be reduced. Therefore, the grip part 221 can be easily gripped, and the workability of the operator is improved.

  Further, by disposing all the substrates (the power supply substrate 82, the control substrate 83, and the FET substrate 284) of the motor drive circuit 208 so as to be substantially concentric with the motor 3, a wasteful space is defined in the grip portion 221. The diameter of the grip portion 221 can be reduced without being formed. Therefore, the grip part 221 can be easily gripped, and the workability of the operator is improved.

  In addition, since the through hole 284a is formed in the FET substrate 284, the cooling air flows from the air passage 2c (2d) to the FET 287 through the through hole 284a. A grinder can be provided.

  The disc grinder according to the present invention is not limited to the above-described embodiment, and various modifications and improvements are possible. For example, in the third embodiment, all the substrates (the power supply substrate 82, the control substrate 83, and the FET substrate 284) of the motor drive circuit 208 are arranged substantially concentrically with the motor 3, but the disk shown in FIG. Like the grinder 301, at least a part of each substrate may overlap with the motor 3 in the radial direction of the grip portion 321 when viewed from the axial direction of the grip portion 321 of the housing 302. In the disc grinder 301, the power supply substrate 82, the control substrate 83, and the FET substrate 284 are fixed by the grip portion 321 by combining two semi-cylindrical members forming the grip portion 321, and are arranged as described above. Yes. Further, as shown in FIG. 8, from the power line 7 to the power board 82, from the switch 9 to the power board 82, from the power board 82 to the control board 83, from the control board 83 to the FET board 284, and from the FET 287 to the coil of the motor 3. Until then, they are electrically connected by wiring. Even with such a disc grinder 301, it is possible to prevent an increase in the diameter of the grip portion 321 as compared with the case where each substrate of the motor drive circuit is provided on the outer side in the radial direction of the motor 3. In this case, as shown in FIG. 8, the grip 321 includes a motor housing 322 that houses the motor 3, a motor drive circuit 308, and a motor drive circuit housing 323 that has a larger diameter than the motor housing 322. May be provided.

  Further, like the disc grinder 401 shown in FIGS. 9 and 10, the power supply unit 85, the control unit 86, and the FET 287 may be mounted on one circuit board 408. The circuit board 408 is fixed by the grip portion 221 by combining two semicylindrical members forming the grip portion 221. In the disc grinder 401, the power supply line 7 is electrically connected to the circuit board 408 via a smoothing capacitor by a wiring (not shown), and the switch 9 is electrically connected to the circuit board 408 by a wiring (not shown). Has been. However, in such a case, the motor drive circuit cannot be efficiently accommodated in the housing 202, and a space where nothing is accommodated (so-called dead space) is defined. It is necessary to increase the length of 221 in the axial direction. Therefore, like the disc grinder of each embodiment mentioned above, it is preferable that the motor drive circuit is divided into a plurality of substrates.

  In the above-described embodiments and modifications, the diameters of the power supply board 82 and the control board 83 are slightly smaller than the outer diameter of the motor 3, but may be the same as or slightly larger than the outer diameter of the motor 3. Good. Similarly, in the third embodiment, the diameter of the FET substrate 284 is slightly smaller than the outer diameter of the motor 3, but may be the same as or slightly larger than the outer diameter of the motor 3.

  In the above-described embodiments and modifications, the motor drive circuits 8, 108, 208, 308, and 408 have the smoothing capacitor 81, but the smoothing capacitor 81 is not provided, and the power supply line 7 and the power supply substrate 82 are provided. And may be directly connected.

  The electric tool of the present invention can be used for a disc grinder or the like equipped with a brushless motor.

DESCRIPTION OF SYMBOLS 1, 101, 201, 301, 401 ... Disc grinder 2, 202, 302 ... Housing 2a ... Air inflow hole
2b ... Air exhaust hole 2c ... Air passage 2d ... First air passage
2e ... 2nd air passage 3 ... Motor 3A ... Outer peripheral surface of motor
DESCRIPTION OF SYMBOLS 4 ... Gear part 5 ... Grinding wheel 6 ... Fan 7 ... Power supply line 8, 108, 208, 308 ... Motor drive circuit 9 ... Switch
21, 221, 321 ... gripping part 21 A, 221 A ... inner peripheral surface of gripping part
21B: End of gripping part 22: Gear cover 23 ... Guide part 23A ... Opposing surface 31 ... Drive shaft 32, 33 ... Bearing 41 ... Output shaft 41 ... Rotation Shaft 81 ... Smoothing capacitor 82 ... Power supply board 82A ... Mounting surface of power supply board 83 ... Control board 83A ... Mounting surface of control board 84, 184, 284 ... FET substrate
84A, 184A, 284A ... Mounting surface of FET substrate 85 ... Power supply
86: Control unit 87, 187, 287 ... FET
87A, 187A, 287A ... Installation surface of FET
87B, 187B, 287B ... Cooling surface of FET 284a ... Through hole
322: Motor housing portion 323: Motor drive circuit housing portion
408 ... Circuit board

Claims (13)

  1. A housing having a substantially cylindrical gripping portion;
    A brushless motor having a drive shaft and housed in the gripping portion;
    A motor drive circuit housed in the gripper and for driving the brushless motor;
    An electric tool comprising: an output shaft extending in a direction substantially perpendicular to the drive shaft.
  2. A housing having a substantially cylindrical gripping portion;
    A brushless motor having a drive shaft and housed in the gripping portion;
    A motor drive circuit housed in the gripper and for driving the brushless motor;
    A power tool comprising: a switch that protrudes from the other end with respect to one end of the gripping part and extends in an axial direction of the gripping part.
  3.   The electric power tool according to claim 1, wherein the motor drive circuit includes a plurality of substrates.
  4.   The power tool according to claim 3, wherein at least one of the plurality of substrates is disposed such that a mounting surface is substantially perpendicular to an axial direction of the grip portion.
  5.   5. The electric tool according to claim 4, wherein the plurality of substrates are arranged such that a mounting surface of each substrate is substantially perpendicular to an axial direction of the grip portion.
  6.   6. The electric tool according to claim 5, wherein each of the plurality of substrates has a shape substantially the same as an outer shape of the brushless motor.
  7.   7. The electric tool according to claim 5, wherein each of the plurality of substrates has a substantially circular shape and is disposed so as to be substantially concentric with the brushless motor.
  8.   9. The electric tool according to claim 3, wherein at least a part of each of the plurality of substrates overlaps the brushless motor in a radial direction of the grip portion.
  9. further,
    A tip tool removably attached to one end of the housing;
    A gear portion for transmitting a driving force from the brushless motor to the tip tool;
    A power line provided on the other end of the housing for supplying power from an external power source,
    The power supply line, the motor drive circuit, the brushless motor, the gear portion, and the tip tool are arranged in this order from the other end side to the one end side. The electric tool described.
  10. further,
    A tip tool provided on one end of the housing;
    A power line provided on the other end of the housing for supplying power from an external power source,
    The motor drive circuit is connected to the power supply line and rectifies the power supplied from the external power supply; an inverter circuit that converts the rectified power into an inverter signal; and drives the motor based on the inverter signal A switching element substrate comprising a switching element to be
    The power supply line, the rectifier circuit, the inverter circuit, the switching element substrate, and the brushless motor are arranged in this order from the other end side to the one end side. The electric tool described.
  11. further,
    A tip tool provided on one end of the housing;
    A power line provided on the other end of the housing for supplying power from an external power source,
    An air inflow hole is formed on the other end side of the housing, an air discharge hole is formed on one end side of the housing,
    In the housing, an air passage that connects the air inlet hole and the air outlet hole is formed,
    The motor drive circuit includes a switching element substrate having a mounting surface on which a switching element is mounted,
    The switching element has a substantially rectangular parallelepiped shape, and is arranged so that a widest surface of the substantially rectangular parallelepiped shape is substantially parallel to a direction from the other end side to the one end side of the housing. The power tool according to any one of claims 1 to 10.
  12. The housing has a guide portion located in the vicinity of the switching element,
    The power tool according to claim 11, wherein the ventilation path includes a space defined between the guide portion and the switching element.
  13.   The power tool according to claim 11 or 12, wherein a through hole connected to the ventilation path is formed in the switching element substrate.
JP2009020452A 2009-01-30 2009-01-30 Electric tool Active JP5424018B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2009020452A JP5424018B2 (en) 2009-01-30 2009-01-30 Electric tool

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
JP2009020452A JP5424018B2 (en) 2009-01-30 2009-01-30 Electric tool
CN201080002583.1A CN102149515B (en) 2009-01-30 2010-01-07 Power tool
EP10701262.7A EP2391480B2 (en) 2009-01-30 2010-01-07 Power tool
US13/063,748 US8816544B2 (en) 2009-01-30 2010-01-07 Power tool with a housing including a guide portion for guiding cooling air along a switching circuit board
PCT/JP2010/050363 WO2010087235A1 (en) 2009-01-30 2010-01-07 Power tool

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JP2013013960A (en) * 2011-07-01 2013-01-24 Makita Corp Impact tool
JP2013163229A (en) * 2012-02-09 2013-08-22 Makita Corp Electric tool
WO2013136788A1 (en) 2012-03-15 2013-09-19 Hitachi Koki Co., Ltd. Portable electric cutter with fan to cool motor
JP2014148021A (en) * 2013-02-01 2014-08-21 Makita Corp Electric tool
DE102013210971A1 (en) * 2013-06-12 2014-12-18 Robert Bosch Gmbh Electronic unit with a mechanical interface and an electrical interface
JP2015107554A (en) * 2015-03-13 2015-06-11 日立工機株式会社 Power tool
EP2873494A3 (en) * 2013-10-18 2016-04-13 Black & Decker Inc. A handheld grinder with a brushless electric motor
WO2016067810A1 (en) * 2014-10-31 2016-05-06 日立工機株式会社 Electric work machine
JP2016086639A (en) * 2016-02-02 2016-05-19 日立工機株式会社 Electric tool
JP2016087702A (en) * 2014-10-29 2016-05-23 日立工機株式会社 Electric power tool
JP2016158307A (en) * 2015-02-23 2016-09-01 株式会社明電舎 Inverter system
US9457459B2 (en) 2010-12-28 2016-10-04 Hitachi Koki Co., Ltd. Power tool provided with circuit board
JP6035699B2 (en) * 2013-05-31 2016-11-30 日立工機株式会社 Electric tool
US9630310B2 (en) 2013-02-01 2017-04-25 Makita Corporation Electric tool
WO2017082082A1 (en) * 2015-11-13 2017-05-18 日立工機株式会社 Electric tool
JP2017105216A (en) * 2017-03-13 2017-06-15 日立工機株式会社 Portable electric cutter
JPWO2016098564A1 (en) * 2014-12-18 2017-08-31 日立工機株式会社 Electric tool
US9793847B2 (en) 2011-03-18 2017-10-17 Hitachi Koki Co., Ltd. Electric power tool
WO2017187890A1 (en) * 2016-04-28 2017-11-02 日立工機株式会社 Electric tool
WO2018003369A1 (en) * 2016-06-30 2018-01-04 日立工機株式会社 Electrically powered tool
WO2018221108A1 (en) * 2017-05-31 2018-12-06 工機ホールディングス株式会社 Grinder

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US9457459B2 (en) 2010-12-28 2016-10-04 Hitachi Koki Co., Ltd. Power tool provided with circuit board
US10033323B2 (en) 2011-03-18 2018-07-24 Hitachi Koki Co., Ltd. Electric power tool
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JP2016086639A (en) * 2016-02-02 2016-05-19 日立工機株式会社 Electric tool
WO2017187890A1 (en) * 2016-04-28 2017-11-02 日立工機株式会社 Electric tool
WO2018003369A1 (en) * 2016-06-30 2018-01-04 日立工機株式会社 Electrically powered tool
JP2017105216A (en) * 2017-03-13 2017-06-15 日立工機株式会社 Portable electric cutter
WO2018221108A1 (en) * 2017-05-31 2018-12-06 工機ホールディングス株式会社 Grinder

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