JP2016093848A - Power tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mount a control circuit on a substrate mounting a switching element, for eliminating a cable or a wiring cord for mutual wiring, for improving assembly work property and achieving size reduction of a housing.SOLUTION: A housing 1 comprising: a trunk part 2 for storing a brushless motor 10 and an output part 30 to which a tip end tool is connected; a handle part 3 whose one end is connected to the trunk part 2; and a storage part 4 disposed on the other end of the handle part 3, is used, for mounting a control circuit 81 on a FET substrate 80 mounting a FET 71, and the substrate 80 is disposed on a rear side of a motor axial direction in the trunk part.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electric tool that supplies electric power to a motor via a switching element.

  Conventionally, an electric power tool driven by electric power supplied from a commercial AC power source to a commutator motor, for example, an impact driver is known. In recent years, for example, Patent Document 1 proposes an electric tool that uses a brushless motor as a motor and can finely control the rotation speed of the brushless motor by a microcomputer mounted on a control board.

JP 2012-139747 A

  FIG. 5 shows a conventional electric tool shown in Patent Document 1, which includes a housing 1, a brushless motor 10, a striking mechanism unit 20 rotated by the motor 10, and an output unit 30 connected to the striking mechanism unit 20. (A front-rear direction and a vertical direction are defined in the figure).

  The housing 1 includes a body portion 2 that houses the motor 10, the striking mechanism portion 20, and a part of the output portion 30, a handle portion 3 having one end connected to the body portion 2, and the other end of the handle portion 3. And a storage portion 4 formed in the shape. The handle portion 3 is provided with a trigger 5, and the trigger 5 is connected to a switch mechanism 6 accommodated in the handle portion 3. Supply of electric power to the motor 10 and interruption are switched by the trigger 5.

  A power cord 40 is drawn from the lower part of the storage unit 4, and a rectifier circuit board 50 that is connected to the power cord 40 and has a rectifier circuit that converts AC power into DC power is stored in the storage unit 4. A control circuit board 60 on which a control circuit for controlling the rotation of the motor 10 and the like is mounted is also stored in the storage unit 4. A noise filter including a choke coil 41 and a capacitor 42 is inserted between the power cord 40 and the rectifier circuit. The noise filter is housed in the handle portion 3.

  The inverter circuit controlled by the control circuit is mounted on an inverter circuit board (switching element board) 70 disposed behind the motor 10. The inverter circuit has, for example, six FETs 71 as switching elements that turn on and off the energization of the motor 10, and each FET 71 is cooled by an air flow by a fan 15 that rotates together with the motor 10.

  The control circuit includes a drive circuit (gate driver) that outputs a drive signal for turning on / off each FET 71 and a microcomputer, and electrical connection between the control circuit board 60 and the inverter circuit board 70 is performed by a flat cable 72. Yes.

  When the inverter circuit board 70 on which the FET 71 is mounted and the control circuit board 60 on which the control circuit for controlling the FET 71 is located apart from each other as in the prior art of FIG. The number increases, which causes problems such as an obstacle to reducing the diameter of the handle portion 3 so that the operator can easily grip it, and troublesome assembly work.

  The present invention has been made in recognition of such a situation, and its purpose is to install a control circuit on a substrate on which a switching element is mounted, thereby eliminating the need for cables and wiring cords for mutual wiring and assembling work. It is an object of the present invention to provide a power tool capable of improving the performance and reducing the size of the housing.

One embodiment of the present invention is a power tool. The electric tool includes a motor, an output unit that is driven by the motor and to which a tip tool is connected, a body part that houses the motor, a housing that has a handle part that is connected to the body part, and the motor. And a control circuit having a control unit for controlling the switching element,
The control circuit is mounted on a switching element substrate on which the switching element is mounted.

  In the above aspect, the switching element substrate may be disposed at a front or rear position in the axial direction of the motor.

  In the aspect, the control unit may include a drive circuit that outputs a drive signal for turning on and off the switching element, and a microcomputer that controls the drive circuit.

  In the above aspect, it is preferable that the control circuit is mounted on a side of the switching element substrate facing the motor, and the switching element is mounted on a non-facing side.

  In the above aspect, it is preferable that a rotational position detecting element is mounted on a side of the switching element substrate facing the motor.

  In the above aspect, the housing may include a storage portion provided at the other end of the handle portion, and the switching element substrate may be disposed in the storage portion.

  In the above aspect, the housing has a storage portion provided at the other end of the handle portion, and is mounted with a rectifier circuit that converts AC power supplied from a power cord drawn from the storage portion into DC power. A rectifier circuit board may be housed in the housing portion.

  The said aspect WHEREIN: The said switching element board | substrate is arrange | positioned at the said accommodating part, and the said switching element board | substrate is good to be located in the said handle part side rather than the said rectifier circuit board.

  In the above aspect, the control circuit may be configured by a hybrid IC.

Another aspect of the present invention is also a power tool. The electric tool includes a motor, an output unit that is driven by the motor and to which a tip tool is connected, a body part that houses the motor, a housing that has a handle part that is connected to the body part, and the motor. A switching element for supplying electric power to the power supply, and a controller for controlling the switching element
The control unit includes a drive circuit that outputs a drive signal for turning on and off the switching element, and an arithmetic unit that controls the drive circuit, and includes a single control circuit including the drive circuit and the arithmetic unit. It is characterized by being configured as an IC.

  In the another aspect, the control circuit may be mounted on a switching element substrate on which the switching element is mounted.

  In the another aspect, the control circuit may be mounted on a side of the switching element facing the motor, and the switching element may be mounted on a non-facing side.

  It should be noted that any combination of the above-described constituent elements, and those obtained by converting the expression of the present invention between methods and systems are also effective as aspects of the present invention.

  According to the electric tool of the present invention, a cable and a wiring cord for mutual wiring can be made unnecessary by mounting the control circuit on the board on which the switching element is mounted. Further, the assembly workability can be improved, and the housing can be reduced in size.

It is 1st Embodiment of the electric tool which concerns on this invention, Comprising: The sectional side view which shows an impact driver. The control block diagram in 1st Embodiment. The principal part sectional drawing in the 2nd Embodiment of this invention. The sectional side view which shows the 3rd Embodiment of this invention. The sectional side view which shows a prior art example.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or equivalent component, member, process, etc. which are shown by each drawing, and the overlapping description is abbreviate | omitted suitably. In addition, the embodiments do not limit the invention but are examples, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

  An impact driver will be described as a first embodiment of an electric power tool according to the present invention with reference to FIG. 1 and FIG. 2 (front and rear and up and down directions are defined in FIG. 1). Although this impact driver will be described later, the arrangement of the control circuit is different from that of the conventional example of FIG.

  As shown in FIG. 1, the housing 1 includes a body part 2 that houses the brushless motor 10, the striking mechanism part 20, and a part of the output part 30, and a handle part 3 that has one end connected to the body part 2. And a storage portion 4 formed at the other end of the handle portion 3.

  The brushless motor 10 includes an output shaft 11 that extends in the front-rear direction, a rotor 12 that is fixed to the output shaft 11 and includes a plurality of permanent magnets, a stator 14 that is disposed so as to surround the rotor 12 and includes a plurality of stator coils 13, and an output shaft. 11 and a cooling fan 15 fixed to 11. Both sides of the output shaft 11 are axially supported (supported by bearings), and the stator 14 is fixed to the body portion 2 side of the housing 1. The rotation of the output shaft 11 is decelerated via the planetary gear mechanism 16 and applied to the hammer 21 of the striking mechanism unit 20.

  The striking mechanism 20 includes a hammer 21 disposed in a hammer case 25 and a spring 23 that biases the hammer 21 forward. The hammer 21 has a collision portion 22 at the front end, and is rotated by the output shaft of the planetary gear mechanism 16. The anvil 31 that constitutes the output unit 30 includes a collision target 32 at the rear end. Further, the hammer 21 is urged forward by a spring 23 so that the collision portion 22 collides with the colliding portion 32 in the rotation direction when rotating. With such a configuration, when the hammer 21 rotates, the anvil 31 of the output unit 30 is hit. Further, the hammer 21 is configured to be able to move backward against the urging force of the spring, and the hammer 21 resists the urging force of the spring 23 after the collision between the collision portion 22 and the collision target portion 32. Move backward while rotating. And when the collision part 22 gets over the collision part 32, the elastic energy stored in the spring 23 is released, the hammer 21 moves forward, and the collision part 22 and the collision part 32 collide again. Become.

  An anvil 31 constituting the output unit 30 is rotatably supported at the front end portion of the body portion 2, that is, the front end side of the hammer case 25, and a front end tool can be detachably attached to the anvil 31.

  The handle portion 3 is provided with a trigger 5, and the trigger 5 is connected to a switch mechanism 6 accommodated in the handle portion 3. Supply of electric power to the motor 10 and interruption are switched by the trigger 5.

  A power cord 40 is drawn out from a lower outlet 48 of the storage unit 4, and a rectifier circuit board 50 mounted with a rectifier circuit connected to the power cord 40 and converting AC power into DC power is stored in the storage unit 4. Has been.

  Further, an FET substrate (switching element substrate) 80 on which an FET as a switching element is mounted is disposed at a rear position in the axial direction of the motor 10. The FET substrate 80 is fixed to the body 2 side, and a control circuit 81 is mounted on the FET substrate 80 together with, for example, an inverter circuit having six FETs 71. That is, the FET 71 is mounted on the double-sided wiring board 86 and the control circuit 81 is mounted.

  As shown in FIG. 2, the rectifier circuit mounted on the rectifier circuit board 50 includes a diode bridge 45 and a smoothing capacitor 46 for full-wave rectification of commercial AC power (AC 100 V) supplied from the power cord 40. Yes. A noise filter including a choke coil 41 and a capacitor 42 is inserted on the AC input side of the diode bridge 45, and this noise filter is housed in the handle portion 3. The DC output voltage from the rectifier circuit is supplied to an inverter circuit 85 having a FET mounted on the FET substrate 80 and a control circuit 81. The control circuit 81 includes a drive circuit (gate driver) 82 that outputs a drive signal for turning on and off the FET of the inverter circuit 85 and a microcomputer (arithmetic unit) 83 that controls the drive circuit 82. The drive circuit 82 and the microcomputer 83 constitute a control unit. Further, on the FET substrate 80, three Hall ICs 91 serving as rotational position detecting elements are arranged at intervals of 60 ° in order to detect the position of the rotor 12 of the motor 10. The rotational position detection output of each Hall IC 91 is input to the control circuit 81. The output of the switch mechanism 6 activated by the trigger 5 is also input to the control circuit 81.

  When the switch mechanism 6 is actuated by the trigger 5, the control circuit 81 performs on / off control of each FET 71 of the inverter circuit 85 based on the detection output of the rotor position by each Hall IC 91, and moves the rotor 12 in a predetermined direction Control to rotate at a predetermined rotation speed is performed.

  As shown in FIG. 1, the Hall IC 91 is provided on the opposite side to the motor 10 of the double-sided wiring board 86 included in the FET substrate 80, and is disposed close to and opposed to the rotor 12. Is installed. The electrical connection among the FET 71, the control circuit 81, and the Hall IC 91 is made by the wiring pattern of the double-sided wiring board 86.

  Note that the housing portion 4 of the housing 1 is provided with an LED substrate 95 having a display panel 96 exposed on the upper surface side thereof. The display panel 96 is provided with, for example, a striking force switching button for switching the motor rotation speed, a mode switching button for switching between continuous driving and intermittent driving of the motor 10, and the selected striking force and mode are displayed. It has become.

  Next, the overall operation as an impact driver will be described. By connecting the power cord 40 to a commercial AC power source (not shown), driving power is supplied to the control circuit 81. When the operator pulls the trigger 5 in this state, the motor 10 rotates at a rotational speed corresponding to the pulling allowance. As the motor 10 rotates, the hammer 21 of the striking mechanism unit 20 strikes the anvil 31 of the output unit 30, and the tip tool held thereby rotates. The motor 10 stops when the operator releases the trigger 5.

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

(1) Since the control circuit 81 is also mounted on the FET substrate 80 on which the inverter circuit 85 having the FET 71 as the switching element is mounted, an assembly workability can be improved by eliminating the need for cables and wiring cords for mutual wiring. The housing can be downsized.

(2) In the conventional example in which the FET substrate is provided in the body of the housing and the control circuit board is provided in the storage part, cables and wiring cords for mutual wiring pass through the handle part where there is not enough space. However, in the present embodiment, the control circuit 81 is also mounted on the FET substrate 80 in the body part 2, so that the wiring passing through the handle part 3 can be greatly reduced. The diameter can be reduced.

(3) The FET substrate 80 is disposed at the rear position in the axial direction of the brushless motor 10, and the FET 71 and the control circuit 81 can be effectively cooled together with the motor 10 by the air flow of the fan 15 driven by the motor 10. is there.

  FIG. 3 shows a second embodiment of the present invention. In this case, a control circuit 81 including a drive circuit 82 that outputs a drive signal for turning on and off the FET in FIG. The hybrid IC 84 and the Hall IC 91 are arranged on the opposite side of the double-sided wiring board 86 of the FET substrate 80 to the motor 10, and the FET 71 constituting the inverter circuit 85 is arranged on the non-facing side. The hybrid IC 84 has, for example, a configuration in which a bare chip obtained by converting the drive circuit 82 into an IC together with the bare chip of the microcomputer 83 shown in FIG. 2 is housed in one package. The shape can be greatly reduced compared to the combination.

  In the case of the second embodiment, by configuring the control circuit 81 with the hybrid IC 84, it is possible to reduce the size and improve the assembly workability. In addition, cost reduction can be achieved by using the hybrid IC in common for various electric tools. Furthermore, since the hybrid IC 84 is arranged on the opposite side of the mounting surface of the FET 71 in the FET substrate 80, the area of the FET substrate 80 can be reduced. Other configurations and operational effects are the same as those of the first embodiment shown in FIG.

  FIG. 4 shows a third embodiment of the present invention. In this case, the FET substrate 80 on which the FET 71 is mounted is disposed in the housing 4 of the housing 1, and the control circuit 81 is mounted on the FET substrate 80. Further, the FET substrate 80 is molded with an insulating resin having good thermal conductivity, and an LED substrate 95 having a display panel 96 exposed on the upper surface side of the housing portion 4 is integrated on the upper side of the FET substrate 80. . In addition, a wind window portion 7 in which a large number of intake holes for taking in cooling air is formed is provided on the front side of the storage portion 4.

  As shown in FIG. 4, the arrangement of the housing 1 in the storage portion 4 is the order of the outlet 48 of the power cord 40, the rectifier circuit board 50, and the FET substrate 80 in order from the bottom. Is provided with a gap serving as an air flow passage for heat radiation that enters the inside of the storage portion 4 from the wind window portion 7. The FET 71 is disposed so as to face the rectifier circuit board 50 (that is, face the air flow path).

  The rotational position detection board 90 on which the Hall IC 91 for detecting the position of the rotor 12 of the motor 10 is mounted is fixedly disposed behind the motor 10 (between the motor 10 and the fan 15). Other configurations are the same as those of the first embodiment shown in FIG.

  In the case of the third embodiment, by storing the FET 71 as a switching element that supplies power to the motor 10 in the storage unit 4, the front and rear direction of the body unit 2 can be compared to the case where the FETs are arranged before and after the motor. The length can be shortened, and the workability in a narrow place can be improved.

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

  In the second embodiment of the present invention, the hybrid IC of the control circuit 81 has been described. In the first or third embodiment, the control circuit 81 is configured by a hybrid IC and mounted on the FET substrate 80. It is obvious that you can do it.

  In the first and second embodiments, the FET substrate on which the control circuit is also mounted is disposed at the rear in the motor axial direction, but may be disposed at the front in the motor axial direction. Further, the hybrid IC 84 may be disposed on the FET 71 mounting surface side as in FIG. 1, or the control circuit 81 of the first embodiment that does not constitute the hybrid IC 84 is disposed on the opposite side of the motor 10 as in FIG. The FET 71 may be disposed on the opposite surface side. That is, the switching element substrate and the control circuit substrate may be integrated.

  In each embodiment, the impact driver is exemplified as the electric tool. However, the present invention is not limited to the impact driver as long as the electric tool is mounted and driven by an AC power source. For example, a driver drill having a clutch, a hammer drill having a reciprocating striking mechanism, an oil pulse driver having a hydraulic striking mechanism, and the like may be used.

DESCRIPTION OF SYMBOLS 1 Housing 2 Body part 3 Handle part 4 Storage part 5 Trigger 6 Switch mechanism 7 Wind window part 10 Brushless motor 15 Fan 20 Blowing mechanism part 30 Output part 40 Power cord 50 Rectifier circuit board 60 Control circuit board 70 Inverter circuit board 71 FET
80 FET substrate 81 Control circuit 82 Drive circuit 83 Microcomputer 85 Inverter circuit 86 Double-sided wiring substrate 87 Display panel 90 Rotation position detection substrate 91 Hall IC

Claims (12)

A motor,
An output unit driven by the motor and connected to a tip tool;
A housing having a body portion for housing the motor, and a handle portion having one end connected to the body portion;
A switching element for supplying power to the motor;
A control circuit having a control unit for controlling the switching element,
The power tool, wherein the control circuit is mounted on a switching element substrate on which the switching element is mounted.   The electric power tool according to claim 1, wherein the switching element substrate is disposed at a front or rear position in an axial direction of the motor.   The power tool according to claim 1, wherein the control unit includes a drive circuit that outputs a drive signal for turning on and off the switching element, and a microcomputer that controls the drive circuit.   The electric tool according to claim 2 or 3, wherein the control circuit is mounted on a side of the switching element substrate facing the motor, and the switching element is mounted on a non-facing side.   The electric power tool according to any one of claims 2 to 4, wherein a rotational position detecting element is mounted on a side of the switching element substrate facing the motor.   The electric tool according to claim 1, wherein the housing has a storage portion provided at the other end of the handle portion, and the switching element substrate is disposed in the storage portion.   The housing has a storage portion provided at the other end of the handle portion, and a rectifier circuit board on which a rectifier circuit for converting AC power supplied from a power cord drawn from the storage portion into DC power is mounted. The electric tool according to claim 1, wherein the electric tool is stored in the storage portion.   8. The electric tool according to claim 7, wherein the switching element substrate is disposed in the storage portion, and the switching element substrate is located closer to the handle portion than the rectifier circuit substrate.   The power tool according to any one of claims 1 to 8, wherein the control circuit includes a hybrid IC. A motor,
An output unit driven by the motor and connected to a tip tool;
A housing having a body portion for housing the motor, and a handle portion having one end connected to the body portion;
A switching element for supplying power to the motor;
A control unit for controlling the switching element,
The control unit includes a drive circuit that outputs a drive signal for turning on and off the switching element, and an arithmetic unit that controls the drive circuit,
A power tool comprising a control circuit including the drive circuit and the arithmetic unit as a single IC.   The power tool according to claim 10, wherein the control circuit is mounted on a switching element substrate on which the switching element is mounted.   The power tool according to claim 11, wherein the control circuit is mounted on a side of the switching element facing the motor, and the switching element is mounted on a non-facing side.

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