JPS5824235B2 - Vibration isolation device for portable tools - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention operates at a constant cycle, like an electric hammer, for example.
The present invention relates to a vibration isolator for a vibrating portable tool.

Conventionally, in such portable tools such as electric hammers, a vibration isolating comb is interposed between the bundle and the main body to prevent vibration.

However, the main component of vibration in electric hammers and the like is low frequency, and in contrast, the vibration-proof rubber cannot reduce its spring constant from the viewpoint of operability, so it has the disadvantage that it cannot suppress low-frequency vibration. was there.

The present invention was made in view of the above points, and hereinafter, electricity...
The present invention will be explained with reference to the drawings of an example in which the present invention is applied to a machine.

In the figure, 1 is a main body housing, 2 is a bundle provided at the rear of the main body housing 1, and 3 is an armature built in the housing 1, and a pinion 4 is carved at the tip of the armature.

5 is an intermediate gear that meshes with the pinion 4, and is a reduction gear 6.
meshes with

7 is a crankshaft that fits into the reduction gear 6,
An eccentric pin 8 is installed at its lower end.

9 is a connecting rod whose rear end is fitted into the eccentric pin 8;
A piston 11 is attached to the tip via a rod 10.

Reference numeral 12 denotes a striker that is slidably fitted into the inner wall of the cylindrical portion extending forward of the housing 1, and the piston 11 slides on the inner wall.

13 is a pull point. Reference numeral 14 denotes a vibration isolation chamber provided below the cylinder of the housing 1, and a guide bar 15 extending in the reciprocating direction of the piston 11, that is, the vibration direction, is provided at the center.

16 to 18 are cylindrical weights installed in the same circular shape with the guide bar 15 as the center, and 19 to 21 are springs installed on both sides of these weights 16 to 18, respectively. It is what makes up the vessel.

During use of the illustrated electric hammer, the crank 1 and bundle 2 vibrate violently as the piston 11 and striker 12 reciprocate, and the main component of the vibration is due to the fundamental frequency of the reciprocating motion.

However, the fundamental frequency varies depending on the load condition and the like, and higher-order frequency components such as second and third orders of the fundamental frequency may be large.

Therefore, in order to reduce vibration, in addition to the fundamental frequency component, 2.
It is necessary to reduce the frequency component of 3.

In an electric hammer with an illustrated dynamic vibration absorber, the frequency components to be reduced are ω0, αω0, βω0,
When the masses of weights 16 to 18 are ma, mb, and mo, respectively, and the spring constants of springs 19 to 21 are ζ, d, and iki, the masses of weights 16 to 18 and the masses of springs 19 to 21 are set so as to satisfy the following formula. By setting the spring constant, it is possible to reduce the vibrations of the fundamental frequency component of ω0 and the higher-order frequency components of αω0 and βω0.

In the illustrated embodiment, three weights 16 to 18 and three springs 19 to 21 are provided.
As long as there are two or more of them (there is no need to limit it to three).

As described above, according to the vibration isolating device of the present invention, vibration reduction of about 10
Low-frequency vibrations below 0 Hz can be reduced, and since a plurality of weights and springs are arranged concentrically, the dynamic vibration absorber is compact and can be attached to portable tools.

[Brief explanation of the drawing]

The figure is a longitudinal sectional view showing an embodiment in which the device of the present invention is applied to an electric machine. In the figure, 15 is a guide bar, 16 to 18 are weights, and 19 to 18 are weights.
21 is a spring.

Claims (1)

[Claims] 1. A dynamic vibration absorber is installed in the vibration direction by installing a plurality of identical cylindrical weights in the same circular shape around a guide bar, and installing the same number of springs as the number of weights on both sides of these weights. Features: Vibration isolation device for portable tools.