JP2001293666A - Electric driver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric driver charged with no static electricity. SOLUTION: A brush 10 connected to a body frame 35 is brought into contact with an output shaft 3 of a bit unit including a bit 1, thereby releasing static electricity charged to the bit 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an electric screwdriver.

[0002]

2. Description of the Related Art Electric drivers are widely used in electronic product assembly factories and the like. In recent years, the precision of electronic products and the like has been advanced, and the influence of static electricity at the time of assembly work with an electric screwdriver cannot be ignored. In particular, when mounting a substrate or the like, strict measures against static electricity are required. Since the main body of an electric screwdriver is usually a metal product such as aluminum, it is relatively easy to release static electricity by connecting a ground or the like.

[0003]

However, it has not been possible to release static electricity charged in a bit portion where the screw is turned by actually touching the screw and rotating the screw. The bit is rotatably mounted on the main body via the bearing, but since the surface of the ball of the bearing is usually coated with insulating oil, it has a resistance of several hundred kΩ or more, and discharges the static electricity charged on the bit from the main body. I couldn't do that. Therefore, there is a method of using conductive lubricating oil instead of insulating oil.However, a phenomenon such as running out of oil occurs due to the aging of the bearing or the effect of air to attract screws, and the conductivity is maintained for a long time. There was a problem that the static electricity removing effect could not be maintained. An object of the present invention is to solve the above-mentioned problems of the prior art.

[0004]

In order to achieve the above object, an electric screwdriver according to the present invention comprises a body frame formed of a conductive material, a motor housed in the body frame, and a motor driven by the motor. And a brush that is in conductive contact with the bit unit and is in conductive contact with the body frame. With the above configuration, the static electricity charged on the bit is released from the brush in contact with the bit unit to the body frame. When the bit unit has, for example, an output shaft provided between a motor and a bit, the brush can be configured to contact the output shaft. When the bit unit has a clutch provided between the motor and the bit, various modes are possible, such as a configuration in which the brush contacts the clutch.

[0005]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, a motor M is connected to an output shaft 3 via a clutch 4 so as to rotate the output shaft 3. A chuck shaft 2 is provided on the distal end side of the output shaft 3, and the bit 1 is held on the chuck shaft 2 and rotates. The bit 1 is held by a chuck shaft 2 so as to be movable in the axial direction, and is pushed by a spring 6 via a bit pushing plate 5. The bit 1, the chuck shaft 2, the output shaft 3, the clutch 4, the bit push plate 5, and the spring 6 constitute a bit unit.

The output shaft 3 is connected to a base frame 33 via a bearing 7.
It is supported by. The base frame 33 is connected to a body frame 35 via a bearing case 34. The body frame 35 is connected to ground (not shown). The base frame 33, the bearing case 34, and the body frame 35 are made of a conductive material.

[0007] A tip cover 30 is provided outside the bit 1.
Are mounted, and the distal end cover 30 is supported by the distal end cap 31 so as to be movable in the axial direction. The tip cap 31 is fixed to the tip of the base frame 33 by a fixing nut 32.

As shown in FIGS. 1 and 2, a bearing case 34 is in close contact with the inner periphery of the base frame 33, and the milling groove 11 formed in the bearing case 34 is formed as shown in FIG.
The brushes 10, 10 are mounted below. Brush 10,
The tip of 10 is in contact with the outer periphery of the output shaft 3. With this configuration, the static electricity charged on the bit 1 passes through the output shaft 3 from the chuck shaft 2 or the bit pushing plate 5 and the spring 6, and passes through the brush 1
From 0 and 10, it is released to the body frame 35 via the base frame 33 and the bearing case 34. Then, the air is completely released from the ground connected to the body frame 35 to the outside of the system.

FIGS. 3 and 4 show another embodiment. In this embodiment, the brush 10 is configured to contact the clutch 4. A conductive contact ring 12 is mounted on the outer periphery of the clutch 4, and a brush 10 is mounted on the contact ring 12. The brush 10 is screwed into a milling groove 13 formed in the motor mounting block 40 as shown in FIG. 3 and 4, the bit 1, the output shaft 3 and the clutch 4 constitute a bit unit. In the drawings, the same components as those in FIGS. 1 and 2 are denoted by the same reference numerals.

In the configuration shown in FIG. 3, static electricity charged on the bit 1 is released from the output shaft 3, the clutch 4, the brush 10, and the motor mounting block 40 to the body frame 35, and is connected to the ground (shown in FIG. 3). Is escaped through the system.

[0011]

As described above, according to the electric screwdriver of the present invention, the static electricity charged in the bit can be effectively released, so that there is an effect that the adverse effects due to the static electricity can be eliminated.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a front sectional view showing another embodiment of the present invention.

FIG. 4 is a sectional view taken along line AA in FIG. 2;

[Explanation of symbols]

1: bit, 2: chuck shaft, 3: output shaft, 4: clutch, 5: bit push plate, 6: spring, 7: bearing, 1
0: brush, 11: milling groove, 12: contact ring, 1
3: milling groove, 30: tip cover, 31: tip cap, 32: fixing nut, 33: base frame, 34: bearing case, 35: trunk frame, 40: motor mounting block.

Claims (3)

[Claims] 1. A body frame formed of a conductive material, a motor housed in the body frame, a bit unit including a bit rotated by the motor, and conductively contacting the bit unit; An electric screwdriver, comprising: a brush that conductively contacts a body frame. 2. The electric driver according to claim 1, wherein the bit unit has an output shaft provided between the motor and the bit, and the brush contacts the output shaft. 3. The electric driver according to claim 2, wherein the bit unit has a clutch provided between the motor and the bit, and the brush contacts the clutch.