JP2000120773A - Dynamic damper and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure a sufficient space between a mass body and another apparatus and surely avoid the collision of the both by bending the mass body in substantially U-shape, and fixing it to the circumferential surface of an elastic body in the nipped state. SOLUTION: A damper mass 7 that is a mass body is bent in U-shape in a front view to cover an elastic body 8 in the nipping state. Namely, the damper mass 7 is formed of a substantially semicircularly bent base part 7a and both side walls 7b, 7c provided in parallel on both ends of the base part 7a, and the circumferential surface of the elastic body 8 is cured and adhered to a U-shaped inside surface 7f. According to this structure, the lower end surfaces 7d, 7e of both the side walls 7b, 7c are situated on the side of a side member to ensure a space between the lower end surfaces 7d, 7e and the upper surface of the side member. Thus, even if a radial vibration is inputted the collision of the damper mass 7 with the side member can be surely avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dynamic damper mounted in, for example, an engine room of an automobile and a method of manufacturing the same.

[0002]

2. Description of the Related Art Various types of dynamic dampers of this type have been provided, and examples thereof include those described in Japanese Patent Application Laid-Open No. 4-258549.

[0003] In brief, a conventional dynamic damper 50 comprises, as shown in FIG. 10, a support rod 52 erected on a fixed substrate 51 mounted on a vibrating surface,
An elastic body 55 fixed to the outer periphery of the elastic member 55; a mass body 53 having a substantially rectangular cross section (long side) fixed to the outer periphery of the elastic body 55 through the through hole 54; And a thin rubber layer 56 covering the upper surface of the fixed substrate 51.

[0004] When radial vibration is input from the vehicle body to the support rod 52, the elastic body 55 compressively or tensilely deforms in the radial direction to generate a large spring force, and this spring force and mass are increased. The natural frequency determined by the mass of the body increases,
While relatively high-frequency input vibration is absorbed, when axial vibration is input from the vehicle body to the support rod 52, the elastic body 55 is deformed in the axial direction, generating a small spring force and causing natural vibration. The number is reduced and relatively low frequency vibrations are absorbed.

[0005]

However, the dynamic damper is limited in installation space, especially in an engine room, where a large number of devices such as engines are provided. ing. In the conventional dynamic damper, the mass body is arranged on the entire circumference of the elastic body and is designed to be compact as a whole, but when it is still installed in an engine room where installation space is limited, There is a possibility that a part of the mass body may collide with another device or the vehicle body due to vibration of the vehicle body or the like, and as a result, the dynamic damper may damage other devices or the like.

Also, the dynamic damper sets its natural frequency equal to the natural frequency of the vibrating part and absorbs the input vibration by the resonance action. Therefore, if the natural frequency in the vibration input direction is not constant. , Cannot effectively absorb vibration. However, since the mass body of the dynamic damper according to the conventional example is often manufactured by casting or forging, irregularities such as a tapered surface of a core remain on the surface of the through-hole, and the roughness of the surface of the through-hole. And the dimensional accuracy deteriorates. Therefore, the deformation of the elastic body with respect to the input vibration becomes unstable, and the spring force is not constant. For this reason, the natural frequency determined by the spring force of the elastic body and the mass of the mass body becomes unstable, and there is a possibility that a stable resonance action cannot be exhibited.

In order to remove irregularities such as a tapered surface remaining on the surface of the through hole, it is conceivable to separately perform machining such as drill polishing. However, the number of manufacturing steps is increased, and work efficiency is deteriorated. At the same time, the cost must rise.

[0008]

SUMMARY OF THE INVENTION The present invention has been devised in view of the above-mentioned conventional circumstances, and a first aspect of the present invention is directed to a support portion fixed to a predetermined position of a vehicle body and an outer periphery of the support portion. A cylindrical elastic body fixed to the surface, and a mass body fixed to the outer periphery of the elastic body in a fitted state, the natural frequency determined by the spring force of the elastic body and the mass of the mass body A dynamic damper that absorbs the matched vibration of the vehicle body by a resonance action, wherein the mass body is bent substantially in a U-shape, and is fixed to the outer peripheral surface of the elastic body in a sandwiched state. I have. This dynamic damper ensures sufficient space between the mass body and other equipment even when it is installed in places where installation space is limited, especially in the engine room, so that collision between the two can be reliably avoided. it can. Also,
Since the surface roughness and dimensional accuracy of the inner peripheral surface of the mass are good and no irregularities such as the tapered surface of the core are formed,
The deformation of the elastic body against vibration is stabilized. Therefore, the elastic body always generates a constant spring force in the input vibration direction, and the natural frequency determined by the spring force and the mass of the mass body is constant. As a result, the resonance action is stabilized, and the input vibration is effectively absorbed.

The invention according to claim 2 is characterized in that both side walls of the mass body are formed in an expanding tapered shape. Therefore, after the bending process is performed by the bender device, the projecting operation of the convex mold is facilitated.

According to a third aspect of the present invention, there is provided a support portion supported at a predetermined position of a vehicle body, a cylindrical elastic body fixed to an outer peripheral surface of the support portion, and a fixed state fitted to an outer periphery of the elastic body. A method of manufacturing a dynamic damper, comprising a mass body, wherein the vibration of the vehicle body that matches a natural frequency determined by a spring force of the elastic body and a mass of the mass body is absorbed by a resonance action. A square bar-shaped material of a mass body is cut into a predetermined length in advance, and then the cut material is placed on each of the upper surfaces of both side walls of the concave type of the bender device. It is characterized in that it is deformed by being pushed into the concave mold depending on the mold, and bent substantially in a U-shape.

According to this manufacturing method, mechanical processing such as drill polishing is not required, and a mass body having a good inner surface roughness can be manufactured by a simple bending operation.

[0012]

1 to 5 show a dynamic damper 1 according to a first embodiment of the present invention. As shown in FIG. 3, the dynamic damper 1 is mounted on a mounting portion 4 of an engine mount 2 disposed in an engine room by a bolt 5, and the side member 3 is located in the vicinity thereof.

As shown in FIG. 1 and FIG. 2, the dynamic damper 1 has an inner cylindrical member 6 as a support fixed to the mounting portion 4 of the engine mount 2 and an outer peripheral surface of the inner cylindrical member 6. A tubular elastic body 8 bonded with sulfuric acid;
And a damper mass 7 which is vulcanized and bonded to the outer peripheral surface in a fitted state.

As shown in FIG. 2, the inner cylindrical metal fitting 6 is circumferentially positioned by fitting a convex portion 6c at a rear end thereof into a concave portion 4a of the mounting portion 4, and is formed at a central portion. The bolt 5 is inserted into the inserted insertion hole 6a and screwed and fastened to the bolt insertion hole of the mounting portion 4, thereby being fixed to the engine mount 2 and transmitting the vibration of the engine mount 2 as described above. It has become.

The elastic body 8 is made of rubber, and is vulcanized and adhered to substantially the center of the outer peripheral surface 6b of the inner cylinder 6 as shown in FIG. 2 are absorbed through the damper mass 7.

The damper mass 7 is a mass made of a metal such as iron or zinc alloy, and is bent substantially in a U-shape as shown in FIG. It is fitted in the state. That is, this damper mass 7
Has a base 7a bent into a substantially semicircular shape, and the base 7a
And both side walls 7b, 7c having parallel to both ends of
The outer peripheral surface 8a of the elastic body 8 is vulcanized and bonded to the U-shaped inner peripheral surface 7f. Accordingly, the entire damper mass 7 is deviated upward from the axis P of the inner cylindrical member 6, and the lower end surfaces 7d and 7e of the side walls 7b and 7c are, as shown in FIG. 3 and the lower end surface 7
A space L is secured between d, 7e and the upper surface of the side member 3.

The damper mass 7 is bent by the following manufacturing method. That is, as shown in FIGS. 4 and 5, a long material rod 9 having an elliptical cross section is cut into a predetermined length in advance, and then the cut material rod 9 is pressed by a bender device 10 to be bent. Have been.
As described above, the material rod 9 is made of a metal such as iron or zinc alloy. The bender device 10 includes a lower concave mold 11 on which the material rod 9 is placed and an upper concave mold 11 for pressing the material rod 9. And a convex mold 14. The concave mold 11 has a U-shaped concave groove 13 at the longitudinal center of a fitting concave portion 12 formed substantially horizontally on the upper surface. The convex mold 14 has a tip 1 at the center in the longitudinal direction of the fitting convex 15 formed on the lower surface.
6a has a pressing convex part 16 formed in an arc shape.

When the material rod 9 cut to the same size as the fitting concave portion 12 of the concave mold 11 is placed in the fitting concave portion 12 and the material rod 9 is pressed by the convex mold 14, the material rod 9 The lower surface 9b of the groove 9 slides on both edges 13b and 13c of the groove 13 and fits inside the groove 13. Thereafter, the fitting concave portion 12 and the fitting convex portion 15 are fitted to each other, and the lower surface 9b of the material rod 9 is formed.
The whole is in contact with the inner peripheral surface 13a of the concave groove 13 of the fitting concave portion 12, and the entire outer peripheral surface 16b of the convex portion 16 of the convex mold 14 is
As shown by the broken line in FIG. At this time, the material rod 9 is bent and formed on the lower surface 9b side in the same shape as the concave groove 13, and at the same time, the convex portion 16 is formed on the upper surface 9a side.
It is bent and formed in the same shape as.

Thus, the substantially U-shaped damper mass 7 is formed.
The damper mass 7 is formed by bending the material rod 9 whose surface is pre-processed as described above, so that the surface roughness and dimensional accuracy of the inner peripheral surface 7f are improved. No irregularities such as the tapered surface of the core are formed.

Therefore, in the dynamic damper 1 configured as described above, when the vibration F in the radial direction (left-right direction) is input from the engine mount 2 to the inner cylinder 6 as shown in FIG. Since the elastic body 8 undergoes compression deformation or tensile deformation in the radial direction to generate a large spring force, the natural frequency determined by the spring force and the mass of the damper mass 7 increases, and the input vibration F is suppressed by the resonance action. You. On the other hand, as shown in FIG. 2, when an axial vibration F ′ is input to the inner cylinder 6, the elastic body 8 is deformed in the axial direction and a small spring force is generated. And the input vibration F 'is absorbed by the resonance action.

The lower end surfaces 7d, 7 of the side walls 7b, 7c
e is located on the side member 3 side as shown in FIG. 3, and a space L is secured between the lower end surfaces 7 d and 7 e and the upper surface of the side member 3. Even if the vibration F ″ is input, the collision between the damper mass 7 and the side member 3 is reliably avoided.

Further, since the surface roughness and dimensional accuracy of the inner peripheral surface 7f of the damper mass 7 are good and no irregularities such as the tapered surface of the core are formed, the input of the vulcanized and bonded elastic body 8 is performed. The deformation with respect to the vibration is stabilized, and a constant spring force is always generated in the vibration input direction, thereby making the natural frequency in the vibration input direction constant. FIG. 6 shows a dynamic damper 1 according to a second embodiment of the present invention, in which the resonance action is stabilized and the vibration of the engine mount 2 is effectively absorbed. This dynamic damper 1
As shown in FIG. 6, a damper mass 20 is provided in which both side walls 20b and 20c provided at both ends of a base 20a are formed in an expanding tapered shape.

In the dynamic damper 1 according to the second embodiment, since the both side walls 20b and 20c located at both ends of the base 20a of the damper mass 20 are formed in an expanding taper shape, the dynamic damper 1 is folded by the above-described bender device 10. After the bending, the work of pulling out the convex mold 14 is easy, and the work efficiency is improved.

The present invention is not limited to the above embodiment. For example, a material rod 31 having a rectangular cross section as shown in FIG. Can also be provided.

As shown in FIG. 9, both side walls 40b,
A damper mass 40 having a narrow closed taper 40c may be provided. In this case, as the bender device, a device that pushes and bends both ends inward is used instead of the above-described device.

[0026]

As is apparent from the above description, according to the present invention, when mounted on a vehicle body, the mass between the mass and other machinery or side members or the like close to the mass. Since a sufficient space is secured, the mass body does not collide with other machinery due to vibration of the vehicle body, and damage to other machinery is prevented. Therefore,
Even in a place where the installation space is limited, particularly in an engine room, the degree of freedom in mounting the dynamic damper can be secured.

Also, the roughness and dimensional accuracy of the inner peripheral surface of the mass body are good, the deformation of the elastic body against input vibration is stable, the elastic body always generates a constant spring force, and the natural frequency of the dynamic damper decreases. Since it is constant, the resonance action is stabilized, and the vibration is effectively absorbed. Therefore, a step of performing machining such as drill polishing on the inner peripheral surface of the mass body can be omitted, and as a result, work efficiency can be improved and costs can be suppressed.

In particular, according to the second aspect of the present invention, after the bending by the bender device, the protruding-type drawing operation is easy, and the operation efficiency is further improved.

[Brief description of the drawings]

FIG. 1 is a front view of a dynamic damper according to a first embodiment of the present invention.

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

FIG. 3 is a schematic view showing an arrangement state of an engine mount and a side member of a body.

4A is a side view of a material rod, and FIG.

FIG. 5 is a schematic diagram showing a processing state of a damper mass.

FIG. 6 is a front view of a dynamic damper according to a second embodiment of the present invention.

FIG. 7 is a longitudinal sectional view of a dynamic damper showing another example of a damper mass.

8A is a side view of the material plate according to the damper mass of FIG. 7; FIG.

FIG. 9 is a front view of a dynamic damper showing another example of a damper mass.

FIG. 10 is a longitudinal sectional view of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Dynamic damper 2 ... Car body 6 ... Support part (inner cylinder fitting) 7 ... Mass body 7b ... Both side walls 7c ... Both side walls 8 ... Elastic body 8a ... Outer peripheral surface of elastic body 9 ... Material rod 10 ... Bender device 11 ... Concave shape Mold 14 ... Convex mold

Claims (3)

[Claims] A supporting portion fixed to a predetermined position of a vehicle body;
A cylindrical elastic body fixed to the outer peripheral surface of the support portion; and a mass body fixed to the outer periphery of the elastic body in a fitted state, and a spring force of the elastic body and a mass of the mass body. A dynamic damper that absorbs the vibration of the vehicle body that matches the determined natural frequency by a resonance action, wherein the mass body is bent substantially in a U-shape and fixed in a sandwiched state on the outer peripheral surface of the elastic body. A dynamic damper characterized by: 2. The dynamic damper according to claim 1, wherein both side walls of said mass body are formed in an expanding tapered shape. 3. A support portion supported at a predetermined position on a vehicle body,
A cylindrical elastic body fixed to the outer peripheral surface of the support portion; and a mass body fixed to the outer periphery of the elastic body in a fitted state, and a spring force of the elastic body and a mass of the mass body. A method of manufacturing a dynamic damper that absorbs vibration of the vehicle body that matches a determined natural frequency by a resonance action, wherein the rod-shaped material of the mass body is cut into a predetermined length in advance, and then the cut material is cut. Is placed on each upper surface of both side walls of the concave mold of the bender device, and then, approximately the center of the material is pressed into the concave mold by the convex mold and deformed to be bent substantially in a U-shape. A characteristic method of manufacturing a dynamic damper.