JPS6258415B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention provides a structure in which vibrations are provided between the vibrating body and the supporting body in order to ensure that almost no vibration is transmitted from the vibrating body that vibrates periodically to the supporting body. The present invention relates to a vibration isolating device provided. In particular, the present invention relates to a vibration isolator having elastic means acting between a vibrating body and a support, and a hydraulic vibration isolating means.

The vibration isolator according to the present invention is applied to parts where it is necessary to prevent transmission of periodically occurring vibrations. For example, the present invention is applied to mounts for marine engines and automobile engines, mounts for piston compressors and piston pumps, and vibration sources for rotary wing aircraft such as helicopters.

[Prior art]

Generally, in order to prevent the transmission of multi-degree-of-freedom vibrations,
It is necessary to provide a large number of vibration isolators between the vibrating body and the support. In normal machines, vibrations are not only transmitted from the vibrating body to the support;
Vibration transmission in the opposite direction also occurs at the same time. Therefore, in some cases the functions of the vibrating body and the support body may be reversed.

2. Description of the Related Art In a helicopter, it is known to provide a number of vibration isolators between a transmission and a fuselage depending on the number of main shafts for vibration transmission. A typical vibration isolator has a configuration in which a spring and a force generator in an anti-vibration direction are connected in parallel. This vibration isolator is designed to insulate the aircraft from vibrations on the rotor side by partially canceling the dynamic force caused by vibrations at a predetermined location on the aircraft. U.S. Pat. No. 3,322,379 teaches the use of a weight with a mechanical lever ratio as a generator of force in the anti-vibration direction. This vibration isolator using purely mechanical forces is of practical use due to the large volume it occupies, the high wear of the bearings of the swinging parts, and the high technical complexity of its implementation. There is a problem above. In addition, a certain distance must be maintained between the position where the spring force acts and the position where the reaction force generated on the support of the weight acts. generates a dynamic moment. This moment is often undesirable, and in particular it is highly undesirable for the moment to act on the fuselage of the helicopter.

It is also possible to provide a fluid-filled chamber with a variable volume between the vibrating body and the support body, connect this chamber to a cylinder, and arrange the inertial body in the form of a free piston in this cylinder, as described in Canadian Patent No. 781817, for example. It is known from the specification, particularly from FIG. This vibration isolator has the problem of causing frictional losses between the piston and the cylinder and accompanied by fluid flow losses within the cylinder. This device is equivalent to providing a damping device in parallel with the vibration isolator, and the vibration isolating function becomes considerably worse. Furthermore, if the acceleration of the vibration is large, the expansion that occurs in the fluid chamber during the periodic motion causes vaporization of the fluid, further impairing the functionality of the vibration isolator.

[Problem that the invention seeks to solve]

The present invention aims to prevent the above-mentioned problems in conventionally known vibration isolators, particularly in hydraulic vibration isolators. That is, a main object of the present invention is to solve the conventional problem in known fluid type vibration isolators that when the vibration acceleration is large, the volume of the fluid chamber expands excessively, reducing the vibration isolating function. It is.

Further, the present invention provides a fluid-type vibration isolator that functions with almost no wear, has a simple structure, and is practical.

[Means for solving problems]

In the present invention, the above-mentioned problems are solved by the following means. That is, the vibration isolator is constituted by an elastic means provided between the vibrating body and the support body and a fluid type vibration isolating means, and the fluid type vibration isolating means is configured to deform in the direction of the periodic vibration of the vibrating body. A first fluid chamber is provided which is capable of being filled with fluid and a second chamber which is deformable in the direction of periodic vibration and whose effective cross-sectional area is smaller than the effective cross-sectional area of the first fluid chamber. The first fluid chamber and the second chamber are in a relationship such that when the first fluid chamber deforms, the second chamber deforms more than the first fluid chamber by an amount corresponding to the difference in effective cross-sectional area between the two chambers. is combined with Furthermore, a weight is provided to move in response to the deformation of the second chamber.

In the first invention, a spring is provided between the weight and the support and at least one between the weight and the vibrating body, which acts in a direction to increase the fluid pressure within the fluid type vibration isolating means. The spring may be set to a strength such that during operation the fluid volume does not increase to a value greater than the fluid volume at atmospheric pressure.

Further, in the second invention, the above-mentioned first
Two fluid vibration isolation systems consisting of fluid chambers are provided, and at least one second chamber is provided for both vibration isolation systems. The first fluid chambers of both vibration isolation systems are rigidly coupled to each other in such a manner that when the volume of one increases, the volume of the other decreases. The weight is provided to move in response to the deformation of the second chamber.

[Effect]

According to the above configuration of the present invention, the periodic vibration of the vibrating body causes a volume change in the first fluid chamber, and the first
The change in volume of the fluid chamber causes a change in volume in the second chamber that is large enough to correspond to the difference in effective cross-sectional area. As a result, the weight is accelerated, and the inertial force generated by this acceleration causes a pressure change in the fluid, and this pressure change acts on the vibrating body and the support body as a dynamic force. The dynamic force acting on the support is utilized to compensate for the dynamic part of the elastic force acting on the support from the elastic means. By appropriately setting the volumes of the first fluid chamber and the second chamber, the constants of the elastic means, etc., under ideal conditions free of friction and damping, the support body can be The dynamic forces acting on it can be completely eliminated. For example, in the case of a helicopter, the vibrating body is the transmission, the support body is the fuselage,
By placing this vibration isolator between the two, it becomes possible to almost completely eliminate the dynamic force transmitted to the aircraft.

In the configuration of the first invention, the spring disposed between at least one of the weight and the support body and between the weight and the vibrating body acts in a direction to increase the fluid pressure within the fluid type vibration isolating means. By appropriately setting the strength of this spring, it is possible to prevent rapid expansion of the fluid chamber even when the acceleration of vibration is large, and to avoid vaporization of the fluid caused by rapid expansion and the accompanying damage to the vibration isolator. The problem of malfunction is resolved.

In the configuration of the second invention, the two fluid vibration isolation systems are
Since they are combined to prevent rapid expansion of the fluid, the problem of malfunction of the vibration isolator due to rapid expansion of the fluid is similarly solved.

[Preferred embodiment of the present invention]

Although it is not necessary in the present invention to fill the second chamber with fluid, in one preferred embodiment the second chamber is filled with fluid and the first chamber is filled with fluid.
connected to the fluid chamber. If the width of the connection between the first fluid chamber and the second chamber is narrow, a damping effect will occur on the fluid due to flow loss due to a sudden change in cross-sectional area, but in order to eliminate this damping effect, Preferably, the connection between the first fluid chamber and the second fluid-filled chamber has a rounded shape.

In another preferred embodiment of the invention, the second chamber is arranged inside the first fluid chamber in order to reduce the overall length of the vibration isolator. In this case, the second chamber is either opened to the atmosphere or sealed, and the compressible fluid is sealed under positive or negative pressure.

To further reduce the required space, the first fluid chamber is formed by a deformable wall and a rigid wall, the rigid wall has a small cross-sectional area compared to the deformable wall, and at least a portion of the second fluid chamber is formed by a deformable wall and a rigid wall. It is configured to be surrounded by a fluid chamber. In this case, the first fluid chamber will be formed in a ring shape.

〔Example〕

Referring first to FIG. 1, the illustrated vibration isolator comprises elastic means or springs 2 arranged between a vibrating body 1 and a support 4. The vibration isolating device shown in FIG. In the case of a helicopter, the vibrating body 1 is a fitting on the transmission side, and the support body 4 is a fitting on the fuselage side. Vibrations are transmitted from the vibrating body 1 to the support body 4, but in a helicopter, vibrations may be conversely transmitted from the fuselage side to the transmission side. In the illustrated embodiment, the spring 2 is a ring-shaped spring made of glass fiber reinforced plastic. However, the spring 2 may be of any type, such as a plate spring or a coil spring.

A deformable wall, that is, a cylindrical metal bellows 3a, which can be deformed in the direction of periodic vibration of the vibrating body 1, is provided between the vibrating body 1 and the support body 4, and the first fluid chamber 3 is formed by this metal bellows 3a. It is formed.
A deformable wall, that is, a metal bellows or diaphragm 5a that can be deformed in the direction of periodic vibration of the vibrating body 1 is provided below the first fluid chamber 3, and this metal bellows or diaphragm 5a allows the second chamber 5
is formed. In this example, the second chamber 5 is connected to the first fluid chamber 3, and both chambers 3 and 5 are filled with fluid. The second chamber 5 has a cross-sectional area smaller than the cross-sectional area of the first fluid chamber 3. Therefore, when the metal bellows 3a forming the first fluid chamber 3 is deformed due to vibration, the metal bellows or diaphragm 5a forming the second chamber 5 is greatly deformed by an amount corresponding to the difference in cross-sectional area. As shown in the figure, the first
The connecting portion between the fluid chamber 3 and the second chamber 5 is formed in a rounded shape.

A cylindrical sleeve 4a is fixed below the support 4, in which a metal bellows or diaphragm 5a is arranged. A cylindrical connecting body 6 is fixed to the lower end of the metal bellows or diaphragm 5a forming the second chamber 5, and the connecting body 6 is arranged so as to surround the lower part of the metal bellows or diaphragm 5a. A weight 9 is attached to the lower end of the connecting body 6. In the illustrated embodiment,
The weight 9 is composed of a number of plates to enable fine adjustment. The connecting body 6 is a sleeve 4a
The sleeve 4a is inserted into the sleeve 4a, and is supported by bearing means such as a ball bearing 8 so as to be movable in the vertical direction relative to the sleeve 4a. A spring 7 is disposed between a flange formed at the lower part of the sleeve 4a and a flange formed at the upper end of the connecting body 6, and urges the metal bellows or diaphragm 5a of the second chamber upward.

The operation of the structure shown in FIG. 1 is as follows. That is, when the spring 2 is compressed by the vibration of the vibrating body 1, the volume of the first fluid chamber 3 decreases.
The fluid in the fluid chamber 3 moves to the second chamber 5. Therefore, the bellows 5a constituting the second chamber 5 is deformed in the extending direction, and the weight 9 moves downward. Weight 9
When the weight 9 reaches near the bottom dead center of its motion, strong braking is applied to the weight 9, and a strong downward inertial force is generated in the weight 9. This inertial force acts in a direction that reduces the pressure within the chambers 3 and 5. A periodic force, that is, a dynamic force acting on the support body 4 from the spring 2 as the vibrating body 1 vibrates, is acting downwardly on the support body 4 at this point. The inertial force of the weight 9 is the first
influencing the fluid pressure in the fluid chamber 3 and the second chamber 5;
As a result, the dynamic action of the spring 2 on the support 4 is influenced. By appropriately determining the dimensions of the vibration isolator, such as the volume and cross-sectional area of the chambers 3 and 5, it is possible to reduce the sum of dynamic forces acting on the support body 4 at a predetermined frequency to zero. In other words, it is possible to keep the support body 4 in a stationary state despite the vibration of the vibrating body 1. The strength of the spring 7 is set so that the total volume of the chambers 3, 5 does not become larger than the volume of the fluid at atmospheric pressure. By providing this spring 7, the volume of the chambers 3 and 5 expands rapidly even under large vibration acceleration, and the fluid in the chambers 3 and 5 evaporates, reducing the function of the vibration isolator. is resolved. As mentioned above, vibration is
It may be transmitted from the support body 4 to the vibrating body 1, and in this case, the spring 7 can be considered to be provided between the weight 9 and the vibrating body.

FIG. 2 shows another embodiment of the invention. In this embodiment, a rigid cylindrical wall 3b is formed below the metal bellows 3a forming the first fluid chamber 3, and this wall 3b forms a fluid chamber 3c. The wall 3b is formed integrally with the support 4 and has a cross-sectional diameter smaller than the diameter of the metal bellows 3a, so that the diameter of the chamber 3c is smaller than that of the first fluid chamber 3.
smaller than the diameter of As is clear from the figure, chamber 3
c is connected to the first fluid chamber 3. Rigid wall 3b
A metal bellows 5a is arranged inside.
The metal bellows 5a forms a second chamber 5 therein. The upper end of the connecting body 6 is connected to the upper end of the metal bellows 5a. The connecting body 6 extends downward through the second chamber 5, and has a bearing 8 at the lower end of the rigid wall 3b.
It is supported so as to be movable in the vertical direction. A weight 9 is attached to the lower end of the connecting body 6.
Further, a spring 7 is provided to push the connecting body 6 upward. In this example, the second chamber 5 is open to the atmosphere.

In operation, when the vibrating body 1 moves downward, the first fluid chamber 3 is compressed, and the metal bellows 5a forming the second chamber 5 is compressed. Therefore,
The coupling body 6 and the weight 9 are moved downwards, and the same effect as in the embodiment of FIG. 1 is obtained. Although the second chamber 5 is illustrated as being open to the atmosphere, the second chamber 5 may be hermetically sealed and a compressible medium may be sealed inside under positive pressure or negative pressure.

FIG. 3 shows still another embodiment of the present invention, in which two metal bellows 3a forming two first fluid chambers 3 are arranged one above the other with a support 4 in between. The metal bellows 3a are rigidly connected to each other by a rigid case 10. Therefore, when the upper metal bellows 3a is compressed, the lower metal bellows 3a expands. Below the lower metal bellows 3a is a metal bellows 5.
a is arranged, and this metal bellows 5a is located in the second chamber 5.
form. In this example, the second chamber 5 is connected to the first fluid chamber 3 below, and both chambers are filled with fluid. Above the upper metal bellows 3a,
A further metal bellows 5a is arranged, which metal bellows 5a forms an upper second chamber 5. The upper second chamber 5 is connected to the upper first fluid chamber 3, and both chambers are filled with fluid. A vibrating body 1 is formed integrally with the case 10 above the case 10, and a spring 2 serving as an elastic means is provided between the vibrating body 1 and the support body 4. A connecting body 6 is provided passing through the upper second chamber 5, the upper first fluid chamber 3, the lower first fluid chamber 3, and the lower second chamber 5, and the upper end of the connecting body 6 is connected to the upper first fluid chamber 3. Metal bellows 5 of second chamber 5
The upper end of the metal bellows 5a is connected to the upper end of the bellows 5a, and the lower end of the bellows 5a is connected to the lower end of the metal bellows 5a in the second chamber located below. The connecting body 6 is supported by a bearing 8 provided on the support body 4 so as to be movable in the vertical direction, and its lower end is connected to the lower second chamber 5.
It protrudes downward from the top and supports the weight 9.

In this structure, when the spring 2 is compressed by the vibration of the vibrating body 1, the volume of the upper first fluid chamber 3 decreases. Since the metal bellows 3a of the upper first fluid chamber 3 is rigidly connected to the metal bellows 3a of the lower first fluid chamber 3 via the case 10, the volume of the lower first fluid chamber 3 is equal to that of the upper first fluid chamber 3. It increases by the same amount as the volume reduction of the fluid chamber 3. This first fluid chamber 3
As the volume changes, the volume of the upper second chamber 5 increases, and the volume of the lower second chamber 5 decreases. Due to the difference in cross-sectional area between the first fluid chamber 3 and the second chamber 5, the connecting body 6 connected to the metal bellows 5a of the upper second chamber moves upward, and the weight 9 similarly moves upward. In this way, by configuring the fluid vibration damping means with two systems and arranging these two systems so that they act in opposite directions, it is possible to prevent sudden changes in the volume of the fluid chamber. . In this case,
The spring 7 in the previous example is no longer needed.

FIG. 4 shows yet another embodiment of the present invention. In this example, metal bellows 3a forming the first fluid chamber 3 are arranged above and below with the support 4 in between, as in the previous example. Upper metal bellows 3
A rigid wall 3b is provided at the upper part of the fluid chamber 3, forming a fluid chamber 3c having a smaller cross-sectional area than the first fluid chamber 3. Similarly, a rigid wall 3b is provided at the bottom of the lower metal bellows 3a, forming a fluid chamber 3c having a smaller cross-sectional area than the first fluid chamber 3. wall 3
b is connected to the metal bellows 3a and is formed integrally with a case 10 that connects the upper and lower metal bellows 3a to each other. The upper wall 3b is coupled to the vibrating body 1.

Metal bellows 5a are arranged inside the upper and lower walls 3b, respectively, to form a second chamber 5. The second chamber 5 is open to the atmosphere. The upper end of a connecting body 6 is coupled to the lower end of the metal bellows 5a of the lower second chamber 5, and this connecting body 6 extends downward through the upper and lower first fluid chambers 3 and the lower second chamber 5. A weight 9 is supported at the lower end. Furthermore, the connecting body 6 is also coupled to the upper end of the metal bellows 5a of the second chamber 5 below. The support body 4 is provided with a bearing 8 that supports the coupling body 6 so as to be movable in the vertical direction. Vibrating body 1
A spring 2 is arranged between the support member 4 and the support member 4 .

The embodiment shown in FIG. 5, like the previous example, has metal bellows 3a forming the first fluid chamber 3 which are arranged vertically with a support 4 in between. are rigidly coupled to each other. A rigid wall 3b integral with the support body 4 is provided at the upper part of the lower metal bellows 3a, and a fluid chamber 3c having a smaller cross-sectional area than the first fluid chamber 3 is provided inside the rigid wall 3b.
is formed. Inside the wall 3b, there is a second chamber 5.
A second chamber 5 formed by the metal bellows 5a is connected to the first fluid chamber 3 above. A weight 9 is attached to the lower end of the metal bellows 5a. A spring 2 is arranged between the vibrating body 1 and the support body 4.

In this configuration, when the upper first fluid chamber 3 is compressed, the lower first fluid chamber 3 expands by the same amount.
The metal bellows 5a of the second chamber 5 stretches, and the weight 9 moves downward. Other operations are the same as in the previous example.

In the example of FIG. 6, a metal bellows 3a is arranged between the vibrating body 1 and the support body 4, and the metal bellows 3
A first fluid chamber 3 is formed by a. In this example,
The metal bellows 3a has sufficient rigidity so that it can function as a spring between the vibrating body 1 and the support body 4. A metal bellows 5a is arranged in the first fluid chamber 3 inside the metal bellows 3a,
A second chamber 5 is formed by this metal bellows 5a. A connecting body 6 is attached to the upper end of the metal bellows 5a.
are joined at the top. The connecting body 6 extends downward and is supported by a bearing 8 so as to be movable in the vertical direction. In this example, the support 4 is cylindrical, and the connector 6 extends into the cylindrical support 4 and supports a weight 9 at its lower end. A spring 7 is arranged between the lower end of the support body 4 and the weight 9, and urges the weight 9 upward. The strength of the spring 7 is set in the same way as in the embodiments of FIGS.

〔effect〕

In the present invention, the fluid type vibration isolating means has a first fluid chamber filled with fluid that is deformable in the direction of the periodic vibration of the vibrating body, and the effective cross-sectional area is deformable in the direction of the periodic vibration. a second chamber smaller than the effective cross-sectional area of the first fluid chamber, and a weight 9 is provided to move in response to the deformation of the second chamber, and the first fluid chamber and the second chamber are When the first fluid chamber is deformed, the second chamber is deformed more than the first fluid chamber by an amount corresponding to the difference in effective cross-sectional area between the two chambers. By appropriately setting factors such as the volume and effective cross-sectional area of the second chamber, vibration transmission from the vibrating body to the support body can be substantially blocked at a predetermined frequency. This structure of the present invention is simple, has no parts that can cause wear, and fluid attenuation is not a problem. Furthermore, in the configuration of the first invention in which the spring acts on the weight in the direction of increasing the fluid pressure in the fluid type vibration isolating means, when sudden vibrations are encountered,
It is possible to solve the problem that the pressure in the fluid chamber suddenly decreases, causing vaporization of the fluid and reducing the function of the vibration isolating means. Furthermore, in the second invention in which the fluid vibration isolating means is configured by two vibration isolating systems, when the volume of the first fluid chamber of one of the two vibration isolating systems increases, the volume of the other first fluid chamber decreases. Since both the first fluid chambers are rigidly connected to each other in this manner, rapid expansion of the fluid chamber can be prevented as in the first invention.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing one embodiment of the vibration isolating device of the present invention, and FIGS. 2 to 6 are longitudinal cross-sectional views showing different embodiments of the present invention. DESCRIPTION OF SYMBOLS 1... Vibrating body, 2... Spring, 3... First fluid chamber, 4... Support body, 5... Second chamber, 7... Spring,
9... Weight.

Claims (1)

[Scope of Claims] 1. A preventive device provided between a vibrating body that performs periodic vibrations and a support body connected to the vibrating body to prevent periodic vibrations from being transmitted from the vibrating body to the support body. The vibration device includes: an elastic means provided between the vibrating body and the supporting body; and a fluid vibration isolating means provided between the vibrating body and the supporting body, the fluid vibration isolating device comprising: The means includes a first fluid chamber 3 filled with fluid that is deformable in the direction of the periodic vibration of the vibrating body, and a first fluid chamber 3 that is deformable in the direction of the periodic vibration and has an effective cross-sectional area. a second chamber 5 smaller than the effective cross-sectional area of the second chamber 5; a weight 9 is provided so as to move in accordance with the deformation of the second chamber 5; are combined in such a manner that when the first fluid chamber 3 is deformed, the second chamber 5 is deformed more than the first fluid chamber 3 by an amount corresponding to the difference in effective cross-sectional area between the two chambers. a spring disposed between the weight 9 and the support body 4 and between the weight 9 and the vibrating body 1, the spring acting in a direction to increase the fluid pressure within the fluid type vibration isolating means; 7. A vibration isolating device characterized by being provided with a. 2. The vibration isolator according to claim 1, wherein the second chamber is filled with fluid and connected to the first fluid chamber. 3. The vibration isolator according to claim 2, wherein the connection from the first fluid chamber 3 to the second chamber 5 filled with fluid is formed in a shape that reduces flow loss. 4. The vibration isolator according to claim 1, wherein the second chamber 5 is provided within the first fluid chamber 3. 5. The vibration isolation device of claim 4, wherein the second chamber is sealed and filled with a compressible medium. 6. The vibration isolator according to claim 5, wherein the compressible medium in the sealed second chamber is under positive pressure or negative pressure. 7 Claim No. 4 in which the second chamber communicates with the atmosphere
Anti-vibration device. 8. Claims in which the first fluid chamber is formed by a deformable wall and a rigid wall, and the rigid wall forms a ring-shaped chamber arranged to surround at least a portion of the second chamber. The vibration isolator according to any one of items 4 to 7. 9 The cross-sectional area of the rigid wall forming the first fluid chamber is
The vibration isolator according to claim 8, which is smaller than the effective cross-sectional area of the deformable wall. 10 Claim 1, wherein the first fluid chamber and the second chamber are formed by a cylindrical metal bellows or a diaphragm that can be deformed in the axial direction with little friction.
The vibration isolating device according to any one of Items 1 to 9. 11 A patent claim in which the first fluid chamber and the second chamber are formed by a cylindrical metal bellows that can be deformed in the axial direction with little friction, and the elastic means is formed by making the metal bellows have a predetermined rigidity. A vibration isolating device according to any one of items 1 to 9. 12. A vibration isolator that is provided between a vibrating body that performs periodic vibrations and a support body connected to the vibrating body, and that prevents periodic vibrations from being transmitted from the vibrating body to the support body, comprising: an elastic means provided between the vibrating body and the supporting body; and a fluid vibration isolating means provided between the vibrating body and the supporting body, the fluid vibration isolating means being It consists of a first vibration isolation system having a first fluid chamber 3 filled with fluid, deformable in the direction of the periodic vibration of the vibration isolation system, and a second vibration isolation system also having a first fluid chamber, the first and The first fluid chambers of the second vibration isolation system are rigidly coupled to each other in such a manner that when the volume of one increases, the volume of the other decreases, and the first fluid chambers 3 of both vibration isolation systems When the first fluid chamber 3 is deformed with respect to the second chamber 5 which is deformable in the direction of vibration and whose effective cross-sectional area is smaller than the effective cross-sectional area of the first fluid chamber, the second chamber 5 The weight 9 is combined in such a manner that it is deformed more than the first fluid chamber 3 by an amount corresponding to the difference in effective cross-sectional area between the two chambers, and the weight 9 is moved in response to the deformation of the second chamber 5. A vibration isolating device characterized by being provided with. 13. The vibration isolator according to claim 12, wherein the second chamber is formed commonly for the first and second vibration isolators. 14 The second chamber is provided in each of the first and second vibration isolation systems.
The vibration isolator according to item 2.