JPH08118248A - Motor vibration control device of power tool - Google Patents

Abstract

PURPOSE: To protect a motor from the vibration by improving the vibration- control efficiency of a damper, in a motor vibration control device of a power tool. CONSTITUTION: By providing projecting an outer periphery ring 41 or an outer periphery rib at the height of the position Li where a damper 3 generates a permanent deformation, no damage is given to the damper 3 because the damper 3 is abutted to the outer periphery ring 41 or the outer periphery rib before it generates a permanent deformation, even trough the end face of the motor is moved so as to compress the damper 3 by a load generated by a large vibration.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protection device for a motor vibration in an electric power tool.

[0002]

2. Description of the Related Art The prior art will be described with reference to FIGS. It has a housing 5 in which a striking mechanism portion is built in the gear cover 6 and which is a drive source thereof and which is integrated by an external case, and the inner cover is arranged between the gear cover 6 and the housing 5. In the motor vibration isolator of the installed electric tool, in the motor 1, the motor rear metal 7 is fitted in the housing rear metal chamber, the motor front metal 2 is fitted in the inner cover metal chamber, and the inner cover 4 is fitted in the inner cover. The spigot 44 and the housing end face are fitted together to perform radial positioning. Further, in the axial direction, the motor case overall length Lm and the elastic damper 3Ld are inserted between the motor side end surface of the inner cover 4 and the rear metal chamber end surface of the housing 5: Lh, and the inner cover 4 is fixed to the housing 5 with screws or the like. It is positioned. At this time, the damper 3 is compressed to some extent and has a size of Ld and has a biasing force. In the above-described configuration, the damper 3 disposed between the inner cover 4 and the motor 1 protects the motor 1 against vibrations against the axial vibration of the striking portion in the gear cover 6.

However, the damper 3 is provided between the inner cover 4 and the motor 1: When a large vibration occurs at Ld, the motor 1
A large load is generated due to the mass x vibration acceleration, the damper 3 is compressed considerably, a large die is given to the damper 3 and the damper 3 is permanently deformed, and a gap is generated between the damper 3 and the motor 1 to protect against vibration. The effect will be halved, and the motor 1 will be broken, a rare sheet will be generated, and cause a failure. Further, if the damper 3 deteriorates due to secular change, similarly, a gap may occur between the damper 3 and the motor 1.

[0004]

The damper of the conventional motor vibration damping device deteriorates due to permanent deformation and secular change due to a large load generated from a large vibration, resulting in a gap between the motor and the damper. Had occurred. This gap is gradually increased, and the vibration-damping effect of the damper is reduced by half, and the motor has a problem.

An object of the present invention is to improve the vibration damping effect of a motor by preventing permanent deformation and aging of the damper.

[0006]

The above-mentioned object is achieved by providing a convex portion on the inner cover which restricts the compression amount of the damper.

[0007]

[Function] By providing a convex portion for restricting the compression amount of the damper on the damper mounting portion side of the inner cover, when the damper is compressed and deformed by the load (motor mass × vibration acceleration) generated by large vibration, the motor case end surface is It acts so as to contact the inner cover convex portion.

[0008]

Embodiments of the present invention will be described with reference to FIGS. At the tip of the electric power tool, a gear cover 6 having a striking mechanism built therein, a housing 5 having a motor 1 integrated by an outer case, which is a drive source thereof, and a housing 5, are provided between the gear cover 6 and the housing 5. Inner cover 4 arranged
The motor 1 has the motor rear metal 7 fitted in the housing rear metal chamber and the motor front metal 2 fitted in the inner cover metal chamber. The inner cover 4 is positioned in the radial direction by fitting the inner cover 44 and the end surface of the housing 5. Further, in the axial direction, the motor case total length Lm and the elastic damper 3Ld are sandwiched between the motor side end surface of the inner cover 4 and the rear metal chamber end surface Lh of the housing 5, and the inner cover 4 is fixed to the housing 5 with screws or the like for positioning. are doing.
At this time, the damper 3 is compressed to some extent and has a size of Ld.
Further, on the outer peripheral portion of the damper 3, a ring-shaped outer peripheral ring 41 shown in FIG.
Is such that the damper 3Ld is not permanently deformed. The outer peripheral ring 41 may be several outer peripheral ribs 42 shown in FIG.
Further, it may be provided so as to project on the inner diameter side of the damper 3.

[0009]

According to the present invention, by providing the outer peripheral ring at the position before the permanent deformation of the damper, the damper is compressed when a load due to a large vibration from the tip end is applied to the end face of the damper, and the permanent ring is permanently compressed. Before it is deformed, it will not come into contact with the motor end surface and the outer peripheral ring of the inner cover, and will not damage the damper. Since the frequency of occurrence of this large vibration is extremely low, the motor is not damaged and the damper is not permanently deformed, so that no gap is generated between the motor and the damper. That is, the damper can always maintain the anti-vibration effect and protect the motor from vibration.

Further, when the damper is assembled, since it is mounted in the outer peripheral ring, it can be easily incorporated with the inner cover, so that the assemblability is improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing a motor vibration damping device according to the present invention.

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

FIG. 3 is a sectional view taken along the line AA showing another embodiment of FIG.

FIG. 4 is a cross-sectional view showing a conventional motor vibration isolation device.

5 is a cross-sectional view taken along the line AA of FIG.

[Explanation of symbols]

1 is a motor, 2 is a motor front metal, 3 is a damper,
Reference numeral 4 is an inner cover, 5 is a housing, 6 is a gear cover, 7 is a motor rear metal, 41 is an outer peripheral ring, 42 is an outer peripheral rib, and 44 is an inner cover inlay.

Claims (1)

[Claims] 1. A gear cover having a striking mechanism, a housing having a motor, an inner cover provided between the gear cover and the housing, and a damper provided between the inner cover and the motor end surface. A motor vibration damping device for an electric tool, comprising a ring-shaped or several ribs projecting from the inner cover.