JPS622032A - Dynamic vibration damper - Google Patents

Abstract

PURPOSE:To reduce a force which acts on a leaf spring by symmetrically installing both one ends of a pair of leaf springs adjacent to the swinging fulcrum of a weight suspending shaft and increasing distance to a fixed point. CONSTITUTION:An installing point 6a to a suspending shaft 3 is adjacent to a swinging fulcrum 2a of the suspending shaft 3 while, on the other hand, a fixed point 6b to a frame body inner wall is positioned lower than the installing point 6a. That is, the distance l2 to the fixed point 2b from the swinging fulcrum 2a is larger than the distance l1 to the installing point 6a. Accordingly, even when a weight 4 swings large, the displacement of a leaf spring 6 can be made small since the distance l1 from the swinging fulcrum 2a is small, thereby damping a force which acts on the leaf spring.

Description

[Detailed description of the invention] This invention relates to a pendulum spring type dynamic vibration absorber.

In a pendulum spring type dynamic vibration absorber, the amplitude of the pendulum is generally large in order to absorb a large amount of energy, so special consideration must be given to the spring used. In other words, stress should be reduced so that fatigue does not occur even when used for long periods of time. On the other hand, it is also necessary that the spring constant be large enough. However, no dynamic vibration reducer has hitherto been found that can satisfy these requirements.

The object of the present invention is to provide a dynamic vibration absorber that can satisfy the above requirements.

The dynamic vibration absorber of the present invention has a weight suspended at the center of the frame through a suspension shaft, and a pair of U cedar leaf springs, one end of which is symmetrically connected to a swinging fulcrum of the weight suspension shaft. The other end is attached to the inner wall of the frame, and the other end is fixed to the inner wall of the frame.

An embodiment of the present invention will be explained below with reference to the drawings. A bracket 2 is suspended from the center of the top plate 1a of the cylindrical frame 1, and a weight hanging shaft having a weight 4 at the lower end thereof is swingably provided on the bracket. and a leaf spring 6 with a U-shaped cross section.
．． 6 is attached to the hanging shaft 3 at one end and fixed to the inner wall of the frame body 1 at the other end, and is provided symmetrically with respect to the hanging shaft. In this case, the attachment point 6a to the suspension shaft 3 is located adjacent to the swing fulcrum 2a of the suspension shaft, while the attachment point 6b to the wall of the frame is located below the attachment point 6a. That is, the distance 11 from the swing fulcrum 2a to the attachment point 6a is
The distance 12 to is increased.

With the above configuration, even if the weight 4 swings significantly, the distance l of the attachment point 6a from the swing fulcrum 2a! is small, so the displacement of the leaf spring 6 can be made small. This allows the stress acting on the leaf spring to be reduced. Also, heavy @
4, a pressing force P acts on the plate spring 6 at the attachment point 6a, and as the plate spring 6 deforms, the hanging shaft 3 acts on the suspension shaft 3 at the attachment point 6a.
A force acts in the direction of , and its reaction force P' acts on the leaf spring 6. Then, the radius of curvature at the bending point A of the leaf spring 6 is r
, and assuming that the distance from the attachment point 6a to the bending point A is 13, the bending moment MA acting on the leaf spring 6 at the bending point A is M, = p 13 = P' r. By the way, when using leaf springs 6 of the same length, the reaction force P' becomes larger when 11<12 as described above, and 13 also becomes larger than when 1l=12, so the bending moment Since M is small, the stress acting on the leaf spring 6 can be further reduced.

On the other hand, if the required spring constant is kaq when the attachment point position is the position of the weight 4, ie l, then the spring constant when the attachment point position is 11 is k = ke q (1/l,)2
However, this can be solved by increasing the width of the leaf spring 6.

A weight 4 is installed on the hanging shaft 3 so as to be movable in the vertical direction.
By adjusting the distance lf from the swing fulcrum, the natural frequency of the dynamic vibration absorber can be adjusted. Also, attachment point 6
By supporting the plate spring 6 at point a with a pin support structure, the stress acting on the plate spring 6 can be alleviated.

The dynamic vibration absorber of the present invention as described above has a required spring constant and can reduce the stress acting on the leaf spring.

[Brief explanation of the drawing]

Fig. 1 is a front view of an embodiment of the present invention with the frame body taken longitudinally, Fig. 2 is an explanatory diagram of the positional relationship of the main parts, and Fig. 3 is an explanatory diagram when the weight swings. . 1... Frame body, 3... Hanging shaft, 4... Weight, 6...
・U cedar leaf spring.

Claims (1)

[Claims] A weight is swingably suspended from the center of the frame via a hanging shaft, and a pair of U-shaped leaf springs are symmetrically attached with one end adjacent to the swinging fulcrum of the weight hanging shaft, and the other. A dynamic vibration absorber whose ends are fixed to the inner wall of the frame.