JPS6018308Y2 - Electric tool - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a power tool that has a small ventilation hole to prevent the intrusion of foreign matter and to enhance the cooling effect.

Most power tools are powered by a commutator motor that provides high torque, and the tool portion is integrally constructed.

A fan is provided on the rotor to suck in outside air and cool the inside of the motor, thereby reducing the size and weight of the motor and making it capable of withstanding high loads.

However, since foreign matter may enter the motor through this ventilation hole, the ventilation hole is usually provided by forming a large number of elongated slits.

The slits were preferred because they could sufficiently block not only the fingers of the worker but also foreign objects, and they were relatively easy to remove from the mold during mold production.

However, it cannot deal with foreign objects that enter through the narrow gaps of slits, such as shavings from a drill, shavings from a grinder, or sparks from welding. Thin slits could not be used because they would obstruct ventilation and make molding extremely difficult.

Therefore, the ventilation holes for cooling air need to be arranged so that the intake side, where foreign matter is likely to be sucked in, is as far away from the position where the foreign matter is generated as possible, which may become a structural limitation of the power tool.

The present invention has been developed in view of these circumstances, and is intended to protect the inside of the electric motor by sufficiently removing even extremely fine foreign objects such as sparks from explosion welding, and to cool the electric motor well without obstructing ventilation. The purpose of the present invention is to provide a power tool that can be assembled easily and has a structure that is easy to assemble.

Hereinafter, the present invention will be explained based on an embodiment shown in the drawings. Fig. 1 is a top view showing an embodiment of the power tool according to the invention, and Fig. 2 is an enlarged cross-sectional view thereof. FIG. 3 is a longitudinal sectional view of the portion shown in FIG. 2.

In FIG. 1, the electric tool includes a gear box 3 provided on one side of an electric motor 1 via a flange 2, and a disc-shaped grindstone 4 provided at the bottom of the gear box 3. A cover 5 is provided.

The electric motor 1 is formed of a frame 6 whose outer side is molded from resin, and a bundle 7 is integrally formed on the other side.

Further, a large number of slits 8 are provided on the bundle 7 side of the frame 6 to form intake holes 9.

In FIG. 2, a protrusion 10.11 is provided on the inside of the frame 6 and protrudes in the axial direction.
．． A net 12 is inserted between 11 and held therebetween.

In L2, a sulin l-8 is provided on the outer side of the mesh 12, and a ventilation hole 9 formed by the mesh 12 and the slit 8 is formed.

In FIG. 3, the stator core 13 is supported by the protrusion 10, one end of the net 12 is positioned on the bottom 14 of the frame 6, and the other end is pushed by the stator core 13. is positioned.

The net 12 should be rigid and as narrow as possible; if it is not rigid, the outer periphery may be reinforced with a plate, or the net 12 may be placed between a rigid plate and the frame 6. It may be installed so that it is interposed.

In such a configuration, if small shavings enter the slit 8 along with sparks due to contact between the grinding wheel 4 and the workpiece, for example, even if they try to enter the inside of the electric motor 1 through the slit 8, The narrow mesh of the net 12 prevents even fairly small foreign objects from entering the motor 1.

Therefore, by making the mesh 12 narrower, even small foreign objects accompanied by sparks generated during welding or small foreign objects shavings from the grindstone 4 can be easily blocked.

Moreover, even if the mesh 12 becomes narrow, there is almost no resistance to ventilation because of the large number of through holes, and the mesh 12 is effective because it does not become an obstacle to the cooling air vented into the inside of the motor 1.

Regarding manufacturing, the protrusion 10 supporting the stator core 13
．． 11 is formed on the inner circumferential wall of the frame 6 in the axial direction, and the protrusion 1
The angle between the 0.1 m side surface and the inner periphery of the fly h6 is an acute angle of 90 degrees or less, and the net 12 is held between adjacent protrusions 10 and 11.

If this is done, it can be easily attached to the frame 6 of the small-type motive 1, which is usually formed in a cylindrical shape with a bottom, by the insertion step 1.

17. If the ventilation hole 9 is formed near the bottom 14 of the flute, support the net 12 by sandwiching it between the bottom 14 and the stator core 13 and fix it using screws, etc. It's convenient and saves you the trouble of doing it.

Furthermore, by attaching the net 12 in this way, there is no need to make the slit 8 smaller than necessary;
If the slit 8 is made larger, it is possible to obtain a structure that can be easily removed from the mold.

As explained above, according to the present invention, an axially oriented protrusion is provided on the inner circumferential wall of the frame, the protrusion is extended to hold the net, and a through hole such as a slit is formed outside the net of the frame. By providing this, it is possible to reliably remove small foreign objects such as shavings accompanied by sparks and protect the inside of the electric motor, and it is possible to obtain a power tool that is easy to assemble.

[Brief explanation of the drawing]

FIG. 1 is a top view of the power tool according to the present invention;
The figure is a cross-sectional view of the main part, and FIG. 3 is a vertical cross-sectional view thereof. 3... Gear box, 6... Frame, 8... Slit, io, vi...
Protrusion 12... Net.

Claims (1)

[Scope of utility model registration request] Protrusions oriented toward the axis are arranged on the inner periphery of a bottomed cylindrical frame to support the stator core, and a net is sandwiched between the protrusions adjacent to the waist, and a through hole is provided in the frame serving as the outer periphery of the net. A power tool characterized by having ventilation holes.