JPH1089412A - Vibration insulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently reduce vibration of a wide frequency range by setting net axis-direction rigidity low, maintaining the supporting ability for the net axis-direction load which can support objects ion a wide range of load. SOLUTION: This device generates the net rigidity in the axis direction produced by a first elastic body 3 inserted between an object support member 1 and a stationary foundation member 2, and the rigidity in the axis direction as the algebratic total of a negative rigidity produced by several second elastic bodies 4 inserted between the support member 1 and the foundation member 2 on the connection with the work of the first elastic body 3, the net axis- direction load support ability as the algebratic total of the load support ability of the first elastic body 3 and the load support ability of the second elastic body 4. In this case, at lease either one of the connections A or B for both ends of each second elastic body 4 is relative rotational around the shaft center which is vertical to the axis direction of the first elastic body 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for supporting an object having a large mass, such as an automobile engine, and for insulating or reducing vibration transmission from the object to a base member and from the base member to the object. The present invention relates to a vibration isolation device.

[0002]

2. Description of the Related Art It is obvious that in a vibration isolator of this kind, the lower the natural frequency of the device with respect to the frequency applied to an object, the more excellent the vibration isolating effect is exhibited. In order to reduce the natural frequency of the device as much as possible to enhance the vibration isolation effect according to the obvious principle, the rigidity of the elastic body interposed between the support member of the object and the fixed base member must be reduced. Can be considered. However, if means for reducing the rigidity of the elastic body is adopted to lower the natural frequency of the device, the flexure due to the effective load of the object increases as the rigidity of the elastic body decreases, and the shaft by the elastic body increases. There is a trade-off between the vibration isolation effect and the load-bearing ability by lowering the natural frequency of the device by reducing the rigidity of the elastic body, such as the load-bearing capacity in the direction being reduced. .

[0003] As a vibration isolator for solving the above-mentioned conflicting problems, a conventional Japanese Patent Application Laid-Open No. 5-501441 has been proposed.
An apparatus as disclosed in Japanese Unexamined Patent Publication (Kokai) No. H11-27911 is disclosed. FIG. 5 schematically shows the configuration of the vibration isolator disclosed in this publication. When the vibration isolator is interposed between a support member 11 of an object and a stationary base member 12 to generate regular rigidity in the axial direction, A first elastic body 13 having an axial load supporting ability;
A plurality of members which are interposed between the support member 11 and the base member 12 in a state linked to the operation of the first elastic body 13 to generate negative rigidity in the axial direction and have a load supporting capacity in the axial direction. The second elastic body 14 generates net axial stiffness as an algebraic sum of the positive stiffness of the first elastic body 13 and the negative stiffness of the second elastic body 14, and generates the first elastic body 13. And the net elastic load supporting ability is expressed as an algebraic sum of the load supporting capacity of the second elastic body 14 and the load supporting capacity of the second elastic body 14. By combining the first elastic body 13 and the plurality of second elastic bodies 14 that generate negative axial stiffness, the positive stiffness in the axial direction is offset by the negative stiffness in the axial direction to zero or zero. Generates near net axial stiffness, Thus, while increasing the vibration isolation effect by lowering the natural frequency of the device, a large net axial load supporting capacity is obtained as an algebraic sum of the load supporting capacity of the first elastic body 13 and the load supporting capacity of the second elastic body 14. Can be expressed.

[0004]

However, in the conventional vibration isolator disclosed in Japanese Patent Publication No. 5-501441, both ends of each second elastic member 14 are supported by the support member 11 and the base member 12. Are fixedly connected to each other, and when a large mass of an object is applied to the support member 11, the fixed connection points of the second elastic members 14 are twisted or twisted. The negative stiffness (non-linearity) in the axial direction generated by the elastic body 14 is shown by the dotted line of the load-deflection characteristic curve in FIG. 3, and the negative stiffness in the practical load range cannot be increased. The range in which both the vibration isolation effect and the large load supporting ability achieved by setting the natural frequency of the device low is extremely narrow, and is not practical.

The present invention has been made in view of the above situation, and has a low net axial stiffness while maintaining a sufficient net axial load supporting ability to support an object over a wide load range. It is an object of the present invention to provide a vibration isolator capable of efficiently reducing vibration in a wide frequency range.

[0006]

According to a first aspect of the present invention, there is provided a vibration isolator according to the first aspect of the present invention, wherein the vibration isolator is interposed between a support member for an object and a fixed base member in an axial direction. And a first elastic body having a positive rigidity and having an axial load supporting ability, and a shaft interposed between the support member and the base member in a state linked to the operation of the first elastic body. A plurality of second elastic bodies that generate negative stiffness in the direction and have an axial load supporting ability, and algebraic sum of positive stiffness by the first elastic body and negative stiffness by the second elastic body The vibration is configured to generate a net axial stiffness as well as to express a net axial load supporting ability as an algebraic sum of the load supporting ability of the first elastic body and the load supporting ability of the second elastic body. In the insulating device, both the second elastic bodies Wherein at least one connection point of the connection points to the support member and the base member is configured to be relatively rotatable around an axis perpendicular to the elastic main axis direction of the first elastic body. Things.

According to the first aspect of the present invention, the axial rigidity generated by the first elastic body is linked to the operation of the first elastic body and the plurality of first rigid bodies are connected to each other. The net elastic stiffness generated by the second elastic body is offset by the negative axial stiffness generated by the second elastic body, and a net axial stiffness of zero or close to zero is developed. Of these, at least one connection point is configured to be relatively rotatable about an axis perpendicular to the elastic principal axis direction of the first elastic body, so that the second elastic body does not exert twisting or twisting. In addition, the axial negative stiffness (non-linearity) generated by these second elastic bodies can be increased within a practical load range. Thereby, the object can be supported over a wide load range by increasing the net axial load supporting capacity as an algebraic sum of the load supporting capacity of the first elastic body and the load supporting capacity of the second elastic body. However, by setting the net axial stiffness as an algebraic sum of the positive stiffness and the negative stiffness to be low, it is possible to efficiently reduce vibration in a wide frequency range.

In the vibration isolating apparatus according to the first aspect of the present invention, as described in the second aspect, each of the second
In a case where both connection points of the both ends of the elastic body to the support member and the base member are configured to be relatively rotatable about an axis perpendicular to the elastic principal axis direction of the first elastic body, each of the second elastic bodies The negative stiffness can be further increased without applying excessive force to the shaft, and the net axial stiffness can be set lower.

In the vibration isolating device according to the first or second aspect of the present invention, the second elastic body may have a diametrical direction centered on the first elastic body. And a pair of second elastic bodies supporting the support member at an equilibrium position with respect to the base member and the first elastic body. Alternatively, as described in claim 4, Either three or more radially arranged around the first elastic body, and the support member is supported by the three or more second elastic bodies at an equilibrium position with respect to the base member and the first elastic body. You may.

Further, in the vibration isolator according to any one of the first to fourth aspects of the present invention, the net axial stiffness and the net axial load supporting capacity can be adjusted as described in the fifth aspect. When adopting a configuration having means, it is possible to appropriately adjust the net axial stiffness and the net axial load supporting capacity according to the direction or magnitude of the acceleration of the mass object, A predetermined vibration reducing function can be exerted regardless of fluctuations in the use conditions of the object.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view showing an example in which a vibration isolating device according to the present invention is applied to an engine mount for an automobile, and FIG. 2 is a plan view thereof. In FIG. 1, reference numeral 1 denotes an object engine (not shown). The support member 2 to be fixed and fixed is a base member fixed to the engine room. The support member 1 and the base member 2 generate regular rigidity in the axial direction (vertical direction on the paper surface), and The first elastic body 3 made of rubber and having the load supporting capacity in the axial direction is interposed.

Reference numeral 4 denotes a second elastic body comprising a pair of rubber bushes arranged at diametrically opposed positions centering on the first elastic body 3, and the pair of second elastic bodies 4 A pair of rising portions 2A in the base member 2,
The support member interposed between the support member and the upper end of the second elastic member to generate negative stiffness in the axial direction in connection with the operation of the first elastic body, and to have the axial load supporting ability; 1
And the engine is supported at an equilibrium position with respect to the base member 2 and the first elastic body 3. The algebraic sum of the negative rigidity of the pair of second elastic bodies 4 and the positive rigidity of the first elastic body 3 is given as Generates net axial stiffness,
The net load supporting capacity is expressed as an algebraic sum of the load supporting capacity of the first elastic body 3 and the load supporting capacity of the pair of second elastic bodies 4.

The rising portions 2A, 2A of the support member 1 and the base member 2 at both ends of the pair of second elastic members 4.
Are connected to each other via the linear bushes 5 and 5 so as to be relatively rotatable around an axis perpendicular to the elastic main axis direction x-y of the first elastic body 3. Also,
A connection point A on the support member 1 side of the pair of second elastic bodies 4 is supported so as to be displaceable in a horizontal direction along long grooves 6, 6 formed in the side plate portions 1A, 1A of the support member 1. At the same time, an elastic adjustment jig 7 having a tapered surface 7A which comes into contact with the outer peripheral surface of the linear bush 5 forming the displacement connection point A is attached to the support member 1 via a screw mechanism 8 to the first elastic body 3. The position of the elastic adjustment jig 7 is adjusted in the elastic main axis direction xy of the first elastic body 3 so that the position of the second elastic body 4 can be adjusted. The negative stiffness and the load supporting capacity, that is, the net axial stiffness and the net load supporting capacity are adjustable.

In the vibration isolator constructed as described above, when a large load of the engine is applied to the support member 1 and the first elastic member 3 is elastically bent, the connection point A of the second elastic member 4 is adjusted. , B without twisting or twisting the connection points A, B of the second elastic body 4 to the first
By relatively rotating the elastic body 3 in the elastic main axis direction xy, the axial negative stiffness (non-linearity) generated by the second elastic body 4 is shown by the solid line of the load-deflection characteristic curve in FIG. Large in the practical load range. This makes it possible to increase the net axial load supporting capacity as an algebraic sum of the load supporting capacity of the first elastic body 3 and the load supporting capacity of the second elastic body 4 to sufficiently support an engine having a large mass. Although it is possible, it is possible to efficiently reduce vibration in a wide frequency range from the engine to the car body and from the car body to the engine by setting a low net axial stiffness as an algebraic sum of the positive stiffness and the negative stiffness Becomes

The elastic adjustment jig 7 is connected to the first elastic body 3.
By adjusting the position in the elastic main axis direction xy, it is possible to arbitrarily adjust the net axial stiffness and the net load supporting ability. By appropriately adjusting the axial stiffness and the net axial load supporting capacity, a predetermined vibration reducing function can be exerted regardless of fluctuations in engine installation conditions and vibration generation conditions.

In the above embodiment, an example in which the vibration isolating device according to the present invention is applied to an engine mount for an automobile has been described. An effect similar to that of the embodiment can be obtained. For example, FIG. 4 is a schematic plan view showing another embodiment of the vibration isolator, and a first elastic body made of rubber is provided at the center of the axis between the disk-shaped vibrating object support member 1 and the base member 2. 3 and two or more second elastic bodies 4 radially arranged around the first elastic body 3 (four in FIG. 4 but three or more are sufficient). And the upright portion 2A of the base member 2, and the connecting points A,
B are configured to be relatively rotatable about an axis perpendicular to the elastic main axis direction x-y of the first elastic body 3, and a rising portion 2 </ b> A of the base member 2 of each of the second elastic bodies 4.
The position of the connection point B with respect to is adjustable in the radial direction via the screw mechanism 9.

Also in the vibration isolator having the structure shown in FIG. 4, the axial negative stiffness (non-linearity) generated by each second elastic body 4 can be made large within a practical load range. While the net axial load supporting capacity as an algebraic sum of the load supporting capacity and the load supporting capacity of each of the second elastic bodies 4 can be increased to sufficiently support an engine having a large mass, the rigidity and By setting the net axial stiffness as an algebraic sum of negative stiffness low, it is possible to efficiently reduce vibrations in a wide frequency range from all directions.

In the above embodiment, the first elastic body 3 and the second elastic body 4 are made of rubber.
A coil spring may be used.

[0019]

As described above, according to the first to fourth aspects of the present invention, a plurality of second elastic bodies that generate negative rigidity against the positive rigidity generated by the first elastic body are provided. At least one of the connection points to the support member and the base member at both ends is configured to be relatively rotatable around an axis perpendicular to the elastic main axis direction of the first elastic body, so that the second elastic body is twisted. The axial negative stiffness (non-linearity) generated by these second elastic bodies can be increased within a practical load range without exerting any twist or twist. Therefore, while the object can be supported over a wide load range by increasing the net axial load supporting capacity by the combination of the first and second elastic bodies, the algebraic sum of the positive rigidity and the negative rigidity can be obtained. By setting the net axial stiffness low, it is possible to effectively reduce vibration in a wide frequency range.

[0020] In particular, in the vibration isolator, the connecting points of both ends of each of the second elastic members with respect to the supporting member and the base member are set in the elastic principal axis direction of the first elastic member. When configured to be relatively rotatable about an axis perpendicular to the second elastic body, the negative rigidity is set higher and the net axial rigidity is set lower without applying excessive force to the second elastic bodies. The vibration reduction effect can be further enhanced.

According to the fifth aspect of the present invention, in addition to the effects of the first to fourth aspects, the net axial stiffness and the net axial stiffness can be adjusted according to the direction and magnitude of the acceleration of the mass object. The axial load supporting capacity can be appropriately adjusted, and a predetermined vibration reducing function can be exerted regardless of a change in the use condition of the object.

[Brief description of the drawings]

FIG. 1 is a partially cutaway side view showing an example in which a vibration isolator according to the present invention is applied to an engine mount for an automobile.

FIG. 2 is a plan view of FIG.

FIG. 3 is a characteristic diagram showing a comparison between load-deflection curves of a vibration isolator according to the present invention and a conventional vibration isolator.

FIG. 4 is a schematic plan view showing another embodiment of the vibration isolator according to the present invention.

FIG. 5 is a schematic configuration diagram of a conventional vibration isolator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Support member 2 Base member 3 1st elastic body 4 2nd elastic body A, B Connection point

Claims (5)

[Claims] 1. A first elastic body which is interposed between a support member of an object and a stationary base member to generate regular rigidity in an axial direction and has an axial load supporting ability; A plurality of second elastic members interposed between the support member and the base member in a state of being linked to the operation of the elastic member, generating negative rigidity in the axial direction, and having an axial load supporting ability; Generating a net axial stiffness as an algebraic sum of the positive stiffness of the first elastic body and the negative stiffness of the second elastic body, and the load supporting capacity of the first elastic body and the second elastic body A vibration isolator configured to express a net axial load supporting capacity as an algebraic sum of the load supporting capacities of the support members and the base members at both ends of each of the second elastic bodies. At least one connection point Is configured to be relatively rotatable around an axis perpendicular to the elastic main axis direction of the first elastic body. 2. A connection point between both ends of each of the second elastic members with respect to the support member and the base member is configured to be relatively rotatable about an axis perpendicular to the elastic principal axis direction of the first elastic member. The vibration isolator according to claim 1, wherein 3. A pair of said second elastic bodies are disposed at diametrically opposed positions centered on said first elastic body, and said pair of second elastic bodies couple said support member to a base member and a base member. The vibration isolator according to claim 1, wherein the vibration isolator is supported at an equilibrium position with respect to the first elastic body. 4. The three or more second elastic bodies are radially arranged around the first elastic body, and the support member is used as a base member and a first elastic body by the three or more second elastic bodies. 2. The body is supported in an equilibrium position with respect to the body.
Or the vibration isolator according to 2. 5. The vibration isolator according to claim 1, further comprising means for adjusting the net axial stiffness and the net axial load supporting capacity.