JPH11146607A - Dustproof mechanism of power tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent dust such as sand from entering the driving motor of a power tool such as a hammer drill and a concrete hammer, and protect the rotor and so on even if dust enters it. SOLUTION: A power tool is provided with a motor M for operating a cutting blade, a cooling fan 10 fitted on a rotating shaft 9 of the motor M, and an intake opening 6 which is formed at the rear end of a housing 1 and is used to take in cooling air into the inside of the housing 1. Protruding pieces 8, 81, 82, 83 which prevent the intake opening 6 and a peripheral surface from approaching by a fixed amount or more are protrudingly formed near the intake opening 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dustproof mechanism for a power tool having a blade driven by an electric motor.

[0002]

2. Description of the Related Art Conventionally, in a power tool, such as a concrete hammer, in which a blade is driven by an electric motor, an intake port, a cooling fan, and the like are provided to cool the electric motor to take outside air into a motor housing. Has been done. Further, in such a power tool, in order to prevent dust such as gravel from entering the inside of the housing, a porous sponge is provided in an intake port, and a blind structure is used for the intake port. Have been done.

[0003]

However, in the dustproof mechanism provided with a sponge, the sponge is clogged in a relatively short time, and maintenance is troublesome. Then, it is difficult to sufficiently prevent dust from entering.

In most cases, in electric tools such as a concrete hammer, dust such as gravel enters from the air inlet when the air inlet approaches a ground, a wall, or the like more than a certain amount.
At this time, gravel and the like are being sucked together with the outside air. Therefore, as long as the intake port approaches the ground or the like by a certain amount or more, the above dustproof mechanism does not provide a fundamental dustproof measure.

In view of the above, the present invention provides an electric power tool having a mechanism for preventing approach of the air inlet and the ground, which is the biggest cause of intrusion of gravel and the like.

Further, even if dust such as gravel enters through the air inlet, the dust is blown off,
Provided is a power tool capable of protecting a motor rotor.

[0007]

According to a first aspect of the present invention, there is provided an electric motor for operating a blade, a cooling fan attached to a rotating shaft of the electric motor, and a cooling fan formed at a rear end portion of the housing. In a power tool provided with an air inlet for taking in cooling air, a convex body is provided in the vicinity of the air inlet to prevent the air inlet and the peripheral surface from approaching more than a certain distance.

According to a second aspect of the present invention, there is provided an electric motor for operating a blade, a cooling fan attached to a rotating shaft of the electric motor, and a cooling fan formed at a rear end of the housing for taking cooling air into the housing. The dustproof member having a plurality of openings is attached to the rotating shaft inside the intake port.

According to the third aspect of the present invention, a convex body is provided in the vicinity of the air inlet to prevent the air inlet and the surrounding wall from approaching a certain amount or more, and has a plurality of openings. A dustproof member was attached to the rotating shaft inside the intake port.

In the invention according to claim 4, the convex body is detachable.

According to the fifth aspect of the present invention, the dustproof member having a plurality of openings is detachably attached to the rotating shaft.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. However, the present invention is not limited to the illustrated embodiment.

FIGS. 1 to 3 show a first embodiment of the present invention.

In a motor M shown in FIG. 1, a shaft of the motor M and a shaft of a processing blade are substantially perpendicular to each other, such as a concrete hammer, and the rear end of the motor M is in operation. Attached to a downward facing power tool.

The motor M has a cylindrical housing 1.
At the center of the housing 1, a rotating shaft 9 including a rotor 2 and a commutator 7 is rotatably supported by bearings B, B. Further, a cooling fan 10 for sucking outside air and cooling the rotor 2 and the like is attached to the rotating shaft 9 via a spline, a key, or the like in the housing 1 at a front portion inside the housing 1. ing. The air taken in is exhausted from the exhaust port 11. Rotor 2
A field coil 3 to which electric power is supplied is arranged around the, and a brush 4 for collecting and supplying a current is provided in contact with the commutator 7 around the commutator 7.

A tail cover 5 for closing the rear portion of the motor M is attached to the rear end of the motor M. The tail cover 5 is provided with intake ports 6... 6 for taking outside air into the motor casing 1. On the rear end edge of the tail cover 5, a convex body 81 protruding in the outer peripheral direction, which is a feature of the present invention, is formed over the entire circumference.

Even when the tail cover 5 comes into contact with the side wall of the concrete during the work, the convex body 81 prevents the air inlets 6... can do. Therefore, the suction force generated by the cooling fan 10 does not reach the concrete side wall and the like, and it is possible to prevent the processing dust and the like adhering to the concrete side wall and the like from being sucked into the housing 1 together with the outside air.

Further, on the rear end face of the tail cover 5,
82 of a predetermined length are formed. The convex bodies 82 also prevent the inlets 6... 6 from approaching a predetermined distance or more from the lower surface of the concrete being processed or the outer peripheral wall such as the ground.

Therefore, also in this case, similarly, suction of gravel and the like can be prevented without receiving the suction force generated by the cooling fan 10.

Note that, as shown in FIG.
May directly protrude from the lower end of the housing 1. In this case, the outer peripheral surfaces of the convex bodies 8... 8 are provided so as to protrude radially from the outer peripheral surface of the housing 1. With such a configuration, the function of both the convex body 81 and the convex body 82 of the embodiment shown in FIG. On the other hand, the inner peripheral surface of the convex bodies 8... 8 is provided with substantially the same diameter as the outer diameter of the tail cover 5, and the tail cover 5 is fitted to the inner peripheral surface side of the convex bodies 8. Is supposed to be able to.

Further, in FIG. 3, a convex body 83 is provided separately from the motor M, and the motor M is connected via a detachable attachment a.
It is detachable from. The attachment / detachment attachment a has a belt-like body formed on a ring, and both ends thereof are bent outward to face each other to form fixed portions c, c. 83 are attached to the outer surface of the attachment / detachment a. To attach the convex body 83 to the motor M, a predetermined length is protruded from the rear end surface of the tail cover 5, the detachable attachment a is gripped by the housing 1 of the motor M, and a screw b is attached to the fixing portion c. Screw
Tightening is done from the load.

If the length of the projections (8, 82, 83) is too short, the function of preventing the gravel from being sucked is not fulfilled, and if the length is too long, it hinders the work.
The length should be about m.

Next, a second embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIGS.

In this embodiment, a dustproof member 13 is attached to the rear end of the rotating shaft 9 (see FIG. 4). The dustproof member 13 is formed in a disk shape.
3a are provided on concentric circles. The ventilation holes 13a are for ventilating the cooling air drawn into the housing 1 from the intake port 6 (see FIG. 6). Note that the shape of the ventilation hole 13a does not need to be limited to a circle.
As shown in FIG. In addition, as long as the balance is not lost when rotating, it may not be provided on a concentric circle. Further, the dustproof member may be formed by providing a plurality of flat plates radially without providing the dustproof member.

The size of the ventilation hole is such that the motor speed is 2
At 000 rpm, the flow rate of the cooling air to be ventilated is
The thickness is preferably set to be about 0.00157 (m / s). For example, when the shape of the ventilation holes 13a is circular as shown in FIG. 6, if the number of the ventilation holes 13a is 10, the diameter may be about 10 mm.

On the other hand, a column-shaped boss 132 is provided at the center of the dustproof member 13. A concave portion is formed on one end surface of the boss portion 132 so as to be fitted to the rotating shaft 9, and a hole is provided in the other end surface thereof so as to be screwed to the rotating shaft 9 in an axial direction.

A female screw portion is formed on the end face of the rotating shaft 9.
Is detachably attached to the rotating shaft 9 (see FIG. 5).

The dust-proof member rotates to allow the cooling air to pass therethrough and to fly away dust such as gravel that has entered the housing, thereby causing the commutator 7, the brush 4, the rotor 2, etc. Can be protected from

[0029]

As described above, according to the first and third aspects of the present invention, since the convex body is provided at the rear portion of the motor, the side wall, the lower surface, the ground, and the like of the concrete can be removed during the operation. The distance between the outer peripheral wall and the intake port provided at the rear end of the motor can be prevented from approaching more than a certain amount, and the intrusion of dust adhering to the outer peripheral wall without applying the suction force of the cooling fan to the peripheral surface Can be prevented. Further, the same effect can be obtained not only during the work but also when the power tool is put on the ground or the like while the motor is rotated while the work is temporarily stopped.

According to the second and third aspects of the present invention, since the dustproof member is provided, even if the dust enters the housing, the dustproof member enters without impairing the cooling effect inside the housing. To protect commutators, brushes, rotors and the like from dust.

According to the fourth aspect of the present invention, the convex body can be attached and detached as needed. For example, if the processing area is very narrow and handling is inconvenient, and there is a convex body that would be a hindrance, it can be removed for work.

According to the fifth aspect of the present invention, assembly becomes easy. Furthermore, since the removal is very easy, the inside can be easily cleaned.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional view of a motor provided with an access preventing means according to the present invention.

FIG. 2 is a partially sectional side view showing an access prevention means of another embodiment different from the embodiment of FIG. 1;

FIG. 3 is a side view with a partial cross section showing an access preventing means of another embodiment different from the embodiment of FIG. 2;

FIG. 4 is a longitudinal sectional view illustrating a second embodiment of the present invention.

FIG. 5 is a diagram showing a method of attaching dustproof means.

FIG. 6 is a front view showing an embodiment of the shape of the ventilation hole of the dustproof means.

FIG. 7 is a front view showing an embodiment of the shape of the ventilation hole of the dustproof means different from FIG. 6;

FIG. 8 is a front view showing an embodiment of the shape of the vent hole of the dustproof means different from FIGS. 6 and 7;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing 2 Rotor 3 Field coil 4 Brush 5 Tail cover 6 Inlet 7 Commutator 8 Convex body 9 Rotating shaft 10 Cooling fan 11 Haiku hole 13 Dustproof member M Motor

Claims (5)

[Claims] An electric motor for operating a blade is provided.
In a power tool having a cooling fan attached to a rotating shaft of the electric motor and an intake port formed at a rear end of the housing and for taking in cooling air into the motor casing, in the vicinity of the intake port, A dustproof mechanism for a power tool, wherein a convex body is provided to prevent the intake port and the peripheral surface from approaching at least a certain distance. 2. An electric motor for operating the blade,
A power tool comprising: a cooling fan attached to a rotating shaft of the electric motor; and an intake port formed at a rear end of the housing and for taking in cooling air into the housing. Is attached to the rotating shaft inside the intake port. 3. The dustproof mechanism for a power tool according to claim 1, wherein a dustproof member having a plurality of openings is attached to the rotary shaft inside the air inlet. 4. The dustproof mechanism for a power tool according to claim 1, wherein the convex body is detachable. 5. The dustproof member having a plurality of openings,
The dustproof mechanism for a power tool according to any one of claims 2 to 4, wherein the dustproof mechanism is detachably attached to the rotating shaft.