JP2000052279A - Electric tool - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To improve the assemblability and vibration resistance of an electric hammer having a double insulation structure, and to improve the cooling rate of a control circuit housed therein. SOLUTION: A lead wire from a motor is wired to a control circuit 1 through a bottom of a housing 3, a resin case 5 and a sleeve 6 for a double insulation structure are fitted to each other, fixed with a tail cover 10, and The lead wire to be wired is held in the resin case 5. Further, a space is provided on the heat radiating plate of the control circuit by the wall of the case 2, and the fan 1 of the motor is provided.
The cooling air is taken in from the air hole of the tail cover 10 by 1a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double insulation structure of a power tool having an aluminum housing and a control circuit for adjusting the number of revolutions of a motor.

[0002]

2. Description of the Related Art Among conventional power tools having a control circuit for adjusting the number of revolutions, for example, in the case of an electric hammer,
The housing was made of resin, the control circuit was built into the resin handle, and the lead wires were covered with a vinyl tube to provide double insulation.

[0003]

The conventional electric hammer described above has a structure in which the housing is made of resin and thus is easily damaged, and furthermore, has a structure that is weak against impacts such as dropping and falling. In particular, in the case of an electric hammer having a large impact force, the core of the motor is likely to be displaced or disconnected. Further, since a large tightening torque of the screw cannot be obtained, grease leakage may occur. In addition, if a control circuit is built in a resin handle portion using an aluminum housing, it is necessary to separate a sensor for detecting the number of revolutions and the like from the motor from the control circuit body, and wiring becomes more complicated and difficult. Further, when a case or sleeve made of resin is provided in order to incorporate wiring or a control circuit in the housing, it has been necessary to fix the case with a screw or the like.

An object of the present invention is to solve the above-mentioned problems and to provide an electric power tool capable of improving the assemblability and vibration resistance of this type of double insulation structure and improving the cooling effect of a control circuit housed therein. .

[0005]

An object of the present invention is to provide a housing made of aluminum, a wiring path and a space for accommodating a control circuit are covered with a resin case and a resin sleeve, and a circuit integrated with a sensor is housed in the housing. Achieved by incorporating. In addition, by fixing the resin case by sandwiching it with the housing by the tail cover made of resin and fitting the resin sleeve to the resin case, it is possible to fix the case to the housing without the need for screws or the like.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a double insulation structure of an electric hammer according to this embodiment will be described below with reference to FIGS. The control circuit 1 is integrated with a sensor in a resin case (A) 2. S stored in housing 3
The lead wire 4 from the motor held by the holder 12 does not pass through the lateral hole 3a of the housing 3 but is led straight to the bottom of the housing 3 and passes through the square hole 5b of the lead wire guide 5a of the resin case (B) 5. Connected to control circuit 1. The control circuit 1 is housed in a resin case (B) 5 and further housed in a housing 3. At this time, the convex portion 5c of the resin case (B) 5 fits into the rectangular hole 3b of the housing 3 and also fits into the rectangular hole 6a of the resin sleeve 6 inserted into the lateral hole 3a of the housing 3. Sleeve 6
Is fixed in the lateral hole 3 a of the housing 3. Further, the resin case (B) 5 is fixed in the housing 3 by being sandwiched between the housing 3 and a resin tail cover 10 attached to the housing 3. Here, the resin tail cover 10
Is formed with a convex portion (rib), and when the resin case (B) 5 is mounted at a predetermined position, the convex portion is elastically deformed, so that the positioning of the resin case (B) 5 can be more reliably performed. Have gone to. The lead wire 1c of the control circuit 1 is guided from the square hole 5d provided in the convex portion 5c of the resin case (B) 5 through the resin sleeve 6 into the resin handle 7, and is connected to the power cord. 9. Connected to switch 8. The left and right walls 2a of the resin case (A) 2 are
It is higher than the upper and lower walls 2b, and when housed in the resin case (B) 5, a certain space is secured on the heat sink 1a of the control circuit 1. Furthermore, the rotor 1 of the motor
The cooling air sucked up from the air hole 10a of the tail cover 10 by the fan 11a attached to the fan 1 flows in the space above the heat sink 1a from below to above. A lateral rib 2c is further provided on the left and right walls 2a of the resin case (A) 2 on the side far from the dial 1b, and a guide portion 5 of the resin case (B) 5 is provided.
In addition to securing a space through which the lead wire 4 led from the dial b moves, the control circuit 1 is supported so that the dial 1b is not pushed into the housing 3 when the dial 1b is moved by a finger.

[0007]

According to the present invention, the lead wire from the motor is led straight to the bottom of the housing to allow wiring to the control circuit, and a resin case or sleeve for double insulation is fitted to each other, and the tail cover is used. Since it can be fixed by being sandwiched between the housing and the housing, it is possible to provide a double insulation structure of the electric hammer, which facilitates wiring and assembly work. In addition, by providing a fixed space on the heat sink from the left and right walls of the case and taking in cooling air with the motor fan from the air hole of the tail cover, the double insulation structure of the electric hammer with excellent control circuit cooling effect Can be provided. Furthermore, by holding the lead wire in a space where the lead wire provided in the case and the lead of the case through the lead wire and protecting the lead wire from the vibration of the electric hammer, an electric hammer with excellent vibration resistance is provided. A heavy insulation structure can be provided. Further, since the outer periphery is made of an aluminum housing and has a double insulation structure, problems of motor core misalignment, disconnection, and rigidity when the motor falls down are also improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a double insulating structure of an electric hammer according to the present invention.

FIG. 2 is a view as seen from a direction B in a state where a tail cover of FIG. 1 is removed.

FIG. 3 is a sectional view taken along line AA of FIG. 1;

FIG. 4 is an external perspective view of a control circuit according to the present invention.

FIG. 5 is an external perspective view of a resin case (B) according to the present invention.

FIG. 6 is an external perspective view of a resin sleeve according to the present invention.

[Explanation of symbols]

1 is a control circuit, 1a is a heat sink of the control circuit, 1b is a dial, 1c is a lead wire of the control circuit, 2 is a resin case (A), 2a is left and right walls of the case (A), 2b is a case (A ) Upper and lower walls, 2c is a rib of the case (A), 3 is an aluminum housing, 3a is a side hole of the housing, 3b is a square hole of the housing, 4 is a lead wire from a motor, 5 is a resin case (B) 5a is a lead wire guide of the case (B), 5b is a square hole of the lead wire guide, and 5c is the case (B).
5d is a square hole of the convex portion, 6 is a resin sleeve, 6a
Is a square hole in the sleeve, 7 is a resin handle, 8 is a switch, 9 is a power cord, 10 is a resin tail cover, 10
a is a wind hole of a tail cover, 11 is a rotor, 11a is a fan, and 12 is an S holder.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Atsuyuki Kikuchi 1060 Takeda, Hitachinaka-shi, Ibaraki F-term in Hitachi Koki Co., Ltd. (Reference) 2D058 AA15 BB04 CB06

Claims (4)

[Claims] 1. A motor serving as a drive source, an aluminum housing containing a resin S holder for holding a field of the motor and a circuit for controlling the number of rotations of the motor, and a switch for starting or stopping the motor A power tool, comprising: a resin handle having: a resin case and a resin sleeve, wherein the circuit and the lead wire are arranged while being insulated from an aluminum housing. 2. A convex portion is provided on an upper portion of the resin case, and the convex portion fits into a square hole of the aluminum housing and a square hole of the resin sleeve, and is further provided with a resin tail cover. The power tool according to claim 1, wherein the power tool is sandwiched and held between the housing and the housing. 3. The control circuit according to claim 1, wherein a lead wire guide portion of the motor is provided at a lower portion of the resin case, and the lead wire is connected to the control circuit through the bottom of the housing by the guide portion. The power tool according to 1. 4. The power tool according to claim 1, wherein a rib for securing a space is provided in the resin case of the circuit housed in the resin case.