JP2000346123A - Vibration reducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration reducing device lightweight and excellently durable and installable on the body of a helicopter in space saving manner. SOLUTION: This vibration reducing device 1 is made up of a moving part 5 having a V-shape in the side view and consisting of a first flat spring 3 attached to a dynamic mass 2 as the weight, and a second flat spring 4 fixed to the first flat spring 3, and a mounting pedestal 7 supporting the second flat spring 4 as a cantilever and fixed to a body (a body to be vibrated) 6 of a helicopter as an object to be vibrated. When the device 1 is subjected to vibration of the body 6, the moving part 5 resonates to absorb the vibration of the body 6. When the center of gravity of the moving part 5 is arranged just above the pedestal 7 and a moment arm is reduced to zero, vibrational loads acting on the root 4c of the second flat spring 4 are reduced, and thus the device 1 can be produced lightweight and compactly and as a result the durability of the device is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration reducing apparatus which is mounted on a body of a helicopter and reduces vibration transmitted from a vibration source such as an engine to the body using a leaf spring.

[0002]

2. Description of the Related Art FIGS. 2 and 3 show an example of a vibration reducing device for a helicopter using a leaf spring. The vibration reducing device 101 includes a leaf spring 102, and a dynamic mass (weight) attached to a vibration side end 102a of the leaf spring 102.
103, and a mounting base 104 mounted on the fixed-side end 102b of the leaf spring 102, and the like.
The mounting pedestal 104 is connected to the fuselage 106 via a connection fitting 105.

In this device 101, the length, rigidity, and weight of the dynamic mass 103 of the leaf spring 102 are adjusted so that the natural frequency of the vibration reducing device 101 is synchronized with the natural frequency of the body 106 on which the vibration reducing device 101 is mounted. Is set in advance. The vibration reduction device 101 fixed to the body 106 of the helicopter resonates with the vibration of the body 106 and vibrates in the direction indicated by the arrow X in FIG.

[0004]

The vibration reducing device 10
One leaf spring 102 has a fixed end 10 which is one end thereof.
Only 2b is in the state of a cantilever fixed to the mounting base 104. Therefore, when the leaf spring 102 vibrates, a large moment acts on the base 102a, the mounting pedestal 104, and the structure of the body 106 on which the mounting pedestal 104 is mounted. In order to withstand this moment, it is necessary to make the base 102a of the leaf spring 102, the mounting pedestal 104, and the structure of the body 106 on which the mounting pedestal 104 is mounted strong. For this reason, the weight of the vibration reduction device 101 is heavy,
Accordingly, the weight penalty for mounting the vibration reduction device 101 (the weight of the vibration reduction device 101 + the weight increase due to the structural reinforcement of the mounting portion of the body 106 to which the vibration reduction device 101 is mounted) was large. In addition, since a large moment load is concentrated on the root 102a of the leaf spring 102 and acts on the root 102a, fatigue is likely to occur due to stress concentration, and cracks and the like may occur.
Further, one leaf spring 102 requires a long length to obtain a necessary resonance, and therefore, the vibration reducing device 1
01 is large. Therefore, the vibration reducing device 101
A large mounting space is required to mount the camera on the body 106.

Accordingly, a first object of the present invention is to provide a small vibration reducing device having a small mounting space.

A second object of the present invention is to provide a vibration reducing device which can solve the first problem and is lightweight and excellent in durability.

[0007]

In order to solve the above-mentioned first problem, in a vibration reduction device of the present invention, first and second leaf springs are combined in a substantially V-shape and joined together. One end is connected, a weight is attached to the other end of the first leaf spring, and a mounting pedestal to the vibrating body is connected to the other end of the second leaf spring. .

Further, in implementing the present invention, in order to solve the second problem, a configuration is provided in which a center of gravity of a movable portion made of a member other than the pedestal is located substantially directly above the mounting pedestal. It is good to

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a vibration reducing device 1 according to an embodiment of the present invention will be described with reference to FIG.

As shown in FIG. 1, the vibration reducing device 1 includes a dynamic mass 2 as a weight, a first leaf spring 3 having the dynamic mass 2 attached to one end thereof,
A second leaf spring 4 having one end connected to the other end of the leaf spring 3
And a mounting pedestal 7 connected to the other end of the second leaf spring 4.

The first leaf spring 3 is formed in a strip shape. The dynamic mass 2 is fixed to the weight mounting side end 3a forming one end of the first leaf spring 3 by clamping the end 3a from both sides in the thickness direction. A spring connection side end 3b forming the other end of the first leaf spring 3
Is fixed to the upper surface of one end of the second leaf spring 4 by the connecting member 8 and the fastener 10. Thus, both leaf springs 3 and 4 are connected in a V-shape when viewed from the side.

The second leaf spring 4 is also formed in the shape of a strip, and is also formed so as to be curved in a gentle S-shape along its longitudinal direction. It is connected to the spring connection side end 3b.
Movable part mounting side end 4b forming the other end of second leaf spring 4
1 is arranged to face the lower side of the dynamic mass 2 in FIG. 1, and is fixed to the upper surface of the mounting base 7 by the mounting member 11 and the fastener 12.

Due to the arrangement of the dynamic mass 2 and the mounting pedestal 7, the center of gravity of the movable portion 5 that resonates with the vibration of the body 6 of the helicopter on which the vibration reduction device 1 is mounted,
It is located substantially directly above the mounting base 7.
In other words, the position of the center of gravity of the movable part 5 composed of components other than the mounting base 7 such as the two leaf springs 3 and 4 and the dynamic mass 2 is the mounting part of the vibration reduction device 1 on the helicopter body 6 side (vibration reduction device 1). The first leaf spring 3 and the second leaf spring 4 to which the dynamic mass 2 is attached are connected so as to be located almost directly above the target, that is, so that the moment arm becomes zero. The rigidity of the two leaf springs 3 and 4 and the weight of the dynamic mass 2 are adjusted so that the natural frequency of the movable portion 5 is synchronized with the natural frequency of the body 6.

As described above, the movable portion 5 of the composite leaf spring structure including the two leaf springs 3 and 4 and the dynamic mass 2
It is supported by the mounting base 7. In addition, the vibration reduction device 1 is configured such that the mounting pedestal 7 is
Then, the helicopter is fixed to a predetermined mounting position of the fuselage body 6 using the nuts 14 and the nut 14 so that the helicopter is attached to the body 6.

When the helicopter is not operated, the vibration reducing device 1 having a composite leaf spring structure does not receive vibration from the body 6 as a vibrated body, so that the movable portion 5 is stationary while maintaining an equilibrium (neutral) state. ing. When the helicopter operates and the vibration reducing device 1 receives vibration from the body 6 of the helicopter, the two leaf springs 3 and 4 of the movable portion 5 elastically deform to reduce the vibration. That is, the end 3a of the first leaf spring 3 on the weight mounting side.
Is lower than the equilibrium state, and the spring connection portion 9 including the first leaf spring connection side end 3b, the second leaf spring connection side end 4a, and two connection members 8 is lower than the equilibrium state. When ascending, the dynamic mass 2 tries to return to the neutral position by receiving the reaction force of the first leaf spring 3,
The spring connecting portion 9 tries to return to the neutral position under the reaction force of the second leaf spring 4. Then, by the spring force of the first leaf spring 3 and the second leaf spring 4, contrary to the above, the dynamic mass 2 is raised above the equilibrium state where no vibration is received, and the spring connecting portion 9 is moved above the equilibrium state. Go down. At this time, the dynamic mass 2 tries to return to the neutral position by receiving the reaction force from the first leaf spring 3, and the spring connecting portion 9 tries to return to the neutral position by receiving the reaction force from the second leaf spring 4.
Thereafter, the movable section 5 repeats such an operation alternately, while its amplitude is attenuated and gradually reduced, and eventually converges to the position of the equilibrium state. In this way, the vibration of the body 6 can be reduced by the vibration reduction device 1 vibrating in synchronization with the natural frequency of the body 6.

Further, as described above, since the position of the center of gravity of the movable portion 5 is located directly above the mounting base 7, the moment arm of the movable portion 5 with respect to the mounting portion to the body 6 is substantially zero. it can. Therefore, even if the movable part 5 repeats the above-described vibration, the base 4 of the second leaf spring 4
c, the vibration load (moment) acting on the structural side of the mounting base 7 and the body 6 can be greatly reduced. Therefore,
Since loads on the base 4c of the second leaf spring 4, the mounting base 7, and the structural side of the body 6 can be significantly reduced, fatigue can be reduced, and durability can be improved. The weight penalty for the machine body 6 can be reduced by such a reduction in weight. Moreover, the vibration load (moment) acting on the base 4c of the second leaf spring 4 can be significantly reduced as compared with a vibration reduction device using only one leaf spring.
From the viewpoint of fatigue strength design, the design of both leaf springs 3 and 4 becomes easy. Further, since the length of the spring for obtaining the necessary resonance is obtained by the composite leaf spring structure, each of the first leaf spring 3 and the second leaf spring 4 can be shortened. Can be made compact. Therefore, it can be mounted on the helicopter body 6 in a small installation space.

The present invention is not limited to the above embodiment. For example, the first leaf spring 3 and the second
A plate spring 4 may be integrally connected to be bent into a V-shape. Further, in this specification, “substantially directly above” indicates a relative positional relationship between the center of gravity of the movable portion 5 and the mounting pedestal 7. Not specified.

[0018]

According to the vibration reducing device of the present invention, the movable portion that resonates with the vibration of the vibrating member is provided with the first portion having the weight attached thereto.
Since the two leaf springs, the leaf spring and the second leaf spring, form a V-shape, the first leaf spring and the second leaf spring can be formed short. Therefore, it can be mounted on the vibrated body in a small space.

Further, according to the vibration reducing device, the center of gravity of the movable portion is located almost directly above the mounting base.
Since the moment applied to the root of the second leaf spring, the mounting pedestal, and the mounting portion of the vibrating body to which the mounting pedestal is mounted can be significantly reduced, the structure of the mounting portion of the vibration reduction device of the present invention to the vibrating body can be reduced. In addition to being able to simplify and reduce the weight, the fatigue of the root of the second leaf spring can be suppressed, and the durability thereof can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view of a vibration reduction device according to an embodiment of the present invention.

FIG. 2 is a perspective view of a conventional vibration reduction device.

FIG. 3 is a side view showing a resonance operation of a leaf spring included in the vibration reduction device of FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Vibration reduction device 2 ... Dynamic mass (weight) 3 ... 1st leaf spring 4 ... 2nd leaf spring 5 ... Movable part 6 ... Helicopter body (vibrated body) 7 ... Mounting base

Claims (2)

[Claims] 1. A first leaf spring is combined in a substantially V-shape to connect the joined one ends thereof, and a weight is attached to the other end of the first leaf spring. A vibration reduction device comprising a spring and a mounting pedestal attached to a vibrating body connected to the other end of the spring. 2. The vibration reduction device according to claim 1, wherein a center of gravity of a movable portion made of a member other than the pedestal is located substantially directly above the mounting pedestal.