JPH09254052A - Power drill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make difficult to cause a phenomenon causing ignition of inflammable has and liquid in the periphery by cause of a spark based on collision of an edge point of a drill bit against a drilling object, so as to make a drill resist even anoints continuous use for a long time. SOLUTION: In a condition interrupted from the outside air, a main unit 40 receiving an electrode motor 41 and a drill bit 1 driven by the electric motor 41 are provided. Further, a wet explosion proof mechanism 61, capable if suppressing ignition due to cause of a spark based on collision of a drilling object against a tip end of the bill bit by delivering an explosiniproofing liquid toward the drilling object from a tip end of the drill bit 1, is provided, and a forced cooling mechanism 50, feeding the expolosionproofing liquid to the wet type ecxplosinpoof mechanism 60 after cooling the electric motor 1, is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric drill for use in a site adjacent to a leaking place of flammable gas or liquid, and more specifically, to a main body of the electric drill in a state of being shielded from the outside air. The present invention relates to an electric drill having a housing structure.

[0002]

2. Description of the Related Art In the conventional type electric drill, the main body accommodating the electric motor has a function of isolating the electric motor having an ignition part from flammable gas or liquid.
As a means for dissipating the heat generated in the electric motor, there is no choice but to rely only on natural heat dissipation.

[0003]

Therefore, in this type of electric drill, there is a possibility that flammable gas or liquid in the vicinity may be ignited by the generation of sparks due to the collision between the cutting edge of the drill bit and the object to be drilled. In addition, since the electric motor cannot be cooled by the circulation with the outside air, the electric motor is easily overheated and cannot be used for a long time. The purpose of the present invention is
In view of the above drawbacks, it is difficult for the phenomenon of flammable gas or liquid to ignite due to the generation of sparks due to the collision between the cutting edge of the drill bit and the object to be drilled, and also because the means for preventing overheating of the electric motor is provided. It is to provide an electric drill that can withstand long-term use.

[0004]

[Means for Solving the Problems]

<1> In order to solve the above problems, an electric drill according to the present invention includes a main body accommodating an electric motor in a state of being shielded from the outside air, and a drill bit driven by the electric motor,
Further, by providing an explosion-proof liquid from the tip of the drill bit toward the object to be drilled, a wet explosion-proof mechanism capable of suppressing ignition due to generation of sparks due to collision between the object to be drilled and the tip of the drill bit, and The characteristic feature is that the explosion-proof liquid has a forced cooling mechanism that is sent to the wet explosion-proof mechanism after cooling the electric motor.

[Effects of the Invention] Due to the above-mentioned features,
In the electric drill according to the present invention, because of the wet explosion-proof mechanism having the form of piercing while ejecting the liquid from the tip, the ignition due to the generation of sparks due to the collision between the object to be pierced and the tip of the drill bit is suppressed. The safer work becomes possible, and since the forced cooling mechanism for cooling the electric motor is provided, the electric motor is less likely to overheat, and therefore, it is possible to continuously use the electric motor for a longer time. Moreover, since the cooling liquid for the wet explosion-proof mechanism is shared as the cooling liquid to be sent to the forced cooling mechanism, there is an advantage that it is not necessary to separately prepare this.

<2> In order to solve the above problems, an electric drill according to the present invention is provided with a housing that houses an electric motor in a state of being shielded from the outside air, and the electric motor is explosion-proof from the tip toward the object to be drilled. It is possible to connect a drill bit having a wet explosion-proof mechanism capable of suppressing the ignition due to the generation of sparks due to the collision with the object to be drilled by discharging the working fluid, and the explosion-proof fluid, after cooling the motor, The feature is that it is equipped with a forced cooling mechanism that is sent to the wet explosion-proof mechanism of the drill bit.

[Effects of the Invention] Due to the above-mentioned features,
In the electric drill according to the present invention, because of the wet explosion-proof mechanism having the form of piercing while ejecting the liquid from the tip, the ignition due to the generation of sparks due to the collision between the object to be pierced and the tip of the drill bit is suppressed. The safer work becomes possible, and since the forced cooling mechanism for cooling the electric motor is provided, the electric motor is less likely to overheat, and therefore, it is possible to continuously use the electric motor for a longer time. Moreover, since the cooling liquid for the wet explosion-proof mechanism is shared as the cooling liquid to be sent to the forced cooling mechanism, there is an advantage that it is not necessary to separately prepare this.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The cooling liquid passage provided in the main body of the electric drill so that the explosion-proof liquid is sent to the wet explosion-proof mechanism after passing through the vicinity of the motor may be a forced cooling mechanism of the electric motor. By carrying out in such a form, it becomes possible to realize an effective forced cooling mechanism by a simple and therefore inexpensive means. And
The cooling liquid passage may be a main body built-in passage integrally provided with the main body on the outer surface or the inner surface side of the main body,
It may be attached to the outer surface of the main body by welding or the like, but on the other hand,
It is also possible to simply install the tube-shaped liquid passage on the outer surface of the main body. With such a configuration in which the tubes are closely attached, the cooling liquid passage can be easily realized at low cost with respect to the drill body having an arbitrary shape.
As the tube, a heat resistant resin such as a commercially available fluororesin tube can be used. In addition, since these resin tubes have flexibility, they can be easily wound appropriately and fixed to the outer shapes of the drill main bodies of various shapes.

It is convenient to use a transparent resin tube as the above-mentioned resin tube because it is possible to visually confirm the state in which the liquid is flowing inside. That is, this visual confirmation can be a standard for determining whether or not the electric motor is operated while being cooled as designed, and whether or not the explosion-proof liquid is discharged from the tip of the drill bit.
For the purpose of providing the above-mentioned visual confirmation, a water wheel mechanism that rotates according to the flow of the liquid may be provided in a part of the cooling liquid passage. By carrying out in such a form, it is possible to determine not only whether or not the product is distributed, but also the distribution speed, and a more specific and effective judgment can be made. The water wheel mechanism is not limited to the one using the resin tube, but can be applied to a cooling liquid passage of any form to exert its function.

As a liquid that is supplied near the tip of the drill bit for the purpose of explosion protection and at the same time is circulated in the vicinity of the electric motor for the purpose of cooling the electric motor, it has the effect of suppressing the generation of sparks, and the generated sparks from combustible materials. Water is suitable because of its effect of isolation, cost and availability. When using water as the liquid, let the water pass in the forced cooling mechanism,
Further, as the power for supplying this water to the wet explosion-proof mechanism, it is not necessary to prepare if a normal supply pressure of water supply is used, but a small water absorption pump or the like may be used as the power source. If the latter form is applied, normal work can be performed even in areas with low water pressure such as in highlands, and since water stored in tanks can be supplied, work can be performed in areas remote from water facilities, which is convenient.

An example of the embodiment of the electric drill according to the present invention will be described with reference to FIGS. 1, 2 and 3. First, FIG. 1 is a perspective view showing a usage situation of an embodiment of an electric drill according to the present invention. In this embodiment, the drill device 30 is
It is mounted on a hammer drill type drill body 40 capable of rotating the drill bit 1 particularly while vibrating along its axis. The drill body 40 includes an electric motor 41 for rotating the drill bit 1, a vibrating means 43 such as a vibrator for applying vibration to the drill bit 1 for the purpose of improving the drilling efficiency of the drill device 30,
And a handle 42, 42 for supporting the drill body 40 by an operator. The electric motor 41 and the vibrating means 43 are driven by an alternating current. FIG. 2 is a partially cutaway side view showing a main part of the drill device 30, and FIG. 3 is an exploded perspective view mainly showing the connecting rod member 10 of the drill device 30. As can be seen from FIGS. 2 and 3, the drill body 40 and the drill bit 1 are connected to each other by the connecting rod member 10.
Are connected via A connecting portion 13 having a hexagonal cross-section for receiving the driving force of the electric motor 41 is provided at an upper end of the connecting rod member 10, and a drill bit 1 is provided at a lower end of the connecting rod member 10. A female screw-shaped coupled portion 12 that is detachably coupled to the member 10 and that can transmit the driving force to the drill bit 1 is provided.

As shown particularly well in FIG. 2, the drill device 30 suppresses the generation of sparks due to the contact of the drill bit 1 with the object to be drilled, and the sparks generated are flammable gas or liquid. A wet explosion-proof mechanism 60 is provided for suppressing the ignition. The wet explosion-proof mechanism 60 includes a water supply passage 3 provided in the drill bit 1 and a water supply passage 3
And a water supply mechanism 5 for supplying water from the outside. The water supply channel 3 extends from the one end provided at the center of the end face of the drill bit 1 in the axial direction viewed from the upper end of the drill bit 1 along the axial center of the drill bit 1 to form a single conduit. After branching into two branch pipes at the lower end, they reach the other end provided as a pair of water jet outlets 2 and 2 near the tip in the axial direction of the drill bit 1. The water jet ports 2 and 2 are provided on the rotating peripheral surface of the drill bit 1 at positions excluding the cutting edge portion having the highest hardness. Further, the water jet ports 2 and 2 are provided so as to be directed outward in the radial direction of the drill bit 1 and slightly in the traveling direction when the drill bit 1 is drilled.

The water supply mechanism 5 is fitted onto the connecting rod member 10 so as to be rotatable relative to the liquid jacket member 2.
Has zero. A plurality of annular grooves are formed on the outer surface of the connecting rod member 10 along the circumferential direction of rotation. There are four annular grooves in total, that is, the first annular grooves 14, 14 having a small depth and a small width, which are provided apart from each other in the axial direction of the connecting rod member 10, and the first annular grooves 14, 14. The second annular grooves 15 and 15 having a larger depth and a larger width are also provided between them in the axial direction of the connecting rod member 10. O-rings 16 and 16 made of resin or the like having a small cross-sectional area are inserted in the first annular grooves 14 and 14, respectively, and resin having a larger cross-sectional area is provided in the second annular grooves 15 and 15. The O-rings 17, 17 made of, for example, are inserted into each. The liquid jacket member 20 is provided with a smooth rotary sliding surface 22 on the inner peripheral surface thereof, and the O-ring 16,
16 and O-rings 17 and 17 are in contact with the connecting rod member 10 relatively rotatably, and the water jacket member 20 and the connecting rod member 10 are ring-shaped so that the liquid can enter between them. A water-sealed space 23 is formed. A metal snap ring 25 is used to prevent the water jacket member 20 from coming off the connecting rod member 10.

The water-sealed space 23 is located further axially inward of the inner O-rings 17, 17 fitted to the connecting rod member 10, and the water jacket member 20 is provided with a water supply hose from the outside. It is in communication with a connection joint portion 21 provided for connection. On the other hand, the connecting rod member 10 includes a second water supply passage 11. One end of the second water supply passage 11 communicates with the water supply passage 3 of the drill bit 1 connected to the connecting rod member 10, and the other end opens into the water sealed space 23. The water supplied from the water supply source is irrespective of the rotation angle of the connecting rod member 10 with respect to the water jacket member 20.
1, the water-sealed space 23, the second water supply passage 11, and the water supply passage 3 flow in this order and are ejected from the water ejection ports 2 and 2. A rod-shaped depth gauge 46 extending parallel to the drill bit 1 is fixed to the drill body 40, and is used as a standard for keeping the depth dimension of the hole drilled by the drill bit 1 constant. In addition, the connection joint portion 2 of the water jacket member 20
1 is prevented from co-rotating with the connecting rod member 10 by contacting with the depth gauge 46.

As best shown in FIG. 1, the drill body 40 includes a forced cooling mechanism 5 for cooling the electric motor 41.
0 is provided. This forced cooling mechanism forcibly drives the electric motor 41 connected to the drill body 40 in a state in which the spark generated by the brush of the electric motor 41 or the like is blocked from the outside air so as not to ignite the flammable gas or liquid around the work place. It is effective for cooling. That is, to prevent this explosion, the electric motor 4
The case No. 1 does not have a vent hole for cooling the heat generated from the electric motor 41 itself, so the electric motor 41 is easily overheated and cannot withstand continuous operation for a long time, but the forced cooling mechanism 50 is provided. This enables continuous operation for a longer time. The forced cooling mechanism 50 has flexibility,
It is composed of a fluororesin tube 51 through which the inside can be seen, a small water supply pump 52 fixed to the drill body 40, and the like. The tube 51 is a water storage means 100 such as a water tank.
Extending from one end submerged in the water stored in
It is wound around here several times in a state of being in close contact with the outer surface of the case 1, and then, after passing through the inside of the small water supply pump 52, further through the connecting tube portion 53, to the water supply mechanism 5 of the wet explosion-proof mechanism 60. It is in communication.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration shown in the attached drawings.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of an electric drill according to the present invention.

FIG. 2 is a partially cutaway side view of a main part of the embodiment of FIG.

FIG. 3 is an exploded perspective view of a main part of the embodiment shown in FIG.

FIG. 4 is a schematic diagram showing a forced cooling mechanism.

FIG. 5 is a schematic view of another embodiment of the forced cooling mechanism.

[Explanation of symbols]

 1 Drill Bit 40 Main Body 41 Electric Motor 50 Forced Cooling Mechanism 51 Tube 52 Small Water Supply Pump 60 Wet Explosion Proof Mechanism 100 Liquid Storage Means

Claims (6)

[Claims] 1. An electric motor (41) in a state of being cut off from the outside air.
And a drill bit (1) driven by the electric motor, and discharging the explosion-proof liquid from the tip of the drill bit (1) toward the object to be drilled. A wet explosion-proof mechanism (60) capable of suppressing ignition due to generation of sparks due to collision between an object to be drilled and a tip of the drill bit (1), and the explosion-proof liquid is used after cooling the electric motor. An electric drill equipped with a forced cooling mechanism (50) sent to a wet explosion-proof mechanism (60). 2. The forced cooling mechanism (50) is a cooling liquid passage provided so that the explosion-proof liquid is sent to the wet explosion-proof mechanism (60) after passing through the vicinity of the electric motor (41). The electric drill according to 1. 3. The electric drill according to claim 2, wherein the cooling fluid passage is formed by a tube (51) closely attached to an outer surface of the main body (40). 4. The electric motor (41) in a state of being cut off from the outside air.
A main body (40) accommodating the above is provided, and the electric motor (41) suppresses ignition due to generation of sparks due to collision with the drilling target by discharging an explosion-proof liquid from the tip toward the drilling target. It is possible to connect a drill bit (1) having a possible wet explosion protection mechanism (60), and said wet explosion protection mechanism () of said drill bit (1) after said explosion protection liquid has cooled said electric motor (41). An electric drill equipped with a forced cooling mechanism (50) sent to (60). 5. The main body (4) so that the forced cooling mechanism (50) is sent to the wet explosion-proof mechanism (60) after the explosion-proof liquid has passed near the electric motor (41).
The electric drill according to claim 4, which is a cooling fluid passage provided in 0). 6. The electric drill according to claim 5, wherein the cooling liquid passage is formed by a tube (51) closely attached to an outer surface of the main body (40).