JP3579696B2 - Liquid filled type vibration damping device - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a liquid-sealing type vibration damping device that can obtain a vibration-damping effect based on the flow of a liquid (fluid) sealed therein. It is a liquid-filled type of prevention that is made of a so-called dilatant fluid that is a vibration of frequency and that causes a solidification phenomenon of the liquid under high-amplitude vibration, thereby suppressing the vibration of extremely low frequency. The present invention relates to a vibration device.
[0002]
[Prior art]
Of the anti-vibration devices, especially in the case of an engine mount for an automobile, the engine, which is the power source, is used under various conditions from the idling operation state to the maximum rotation speed, so that it is widely used. It must be able to handle a range of frequencies. In general, vibration isolators as engine mounts are designed to cut off vibrations such as idling vibrations for torque fluctuations caused by explosive combustion of the engine or shakes for resonance phenomena between the engine and the engine mounts. The system is set (tuned). However, in order to prevent (interrupt) these vibrations, it is difficult to avoid the resonance phenomenon by selecting a spring constant, and it is difficult to avoid the resonance phenomenon. In some cases, vibration transmission to the side is interrupted. In order to cope with these plural conditions, a liquid-filled type vibration damping device in which two liquid chambers are provided inside and are connected with an orifice has already been devised and known.
[0003]
By the way, as shown in FIG. 4, for example, the conventional liquid-filled type vibration damping device includes a connecting metal fitting 60 attached to a vibrating body such as an engine, a cup-shaped holder 90 attached to a vehicle body-side member, and the like. An insulator 50 provided between the metal fitting 60 and the holder 90 and made of a vibration isolating rubber or the like; and a main chamber 20 provided below the insulator 50 and filled with an incompressible fluid (liquid). A sub-chamber 30, an orifice 10 which connects the main chamber 20 and the sub-chamber 30 and has an annular shape, an air chamber 70 into which a compressive fluid such as air is introduced, It is basically composed of a diaphragm 40 for partitioning between the chamber 70 and the sub-chamber 30. For the vibration of a predetermined frequency, for example, engine shake, a high damping characteristic is obtained by the action of the orifice 10, and for the idling vibration, the low dynamic spring is formed by the action of the insulator 50. The constant is obtained. In this way, a low dynamic spring characteristic or a high damping characteristic can be obtained with respect to a vibration of a specific frequency, thereby cutting off the idling vibration or engine shake.
[0004]
[Problems to be solved by the invention]
The above-described conventional device having such a configuration is intended to cut off vibrations at frequencies around 10 Hz to 30 Hz, such as engine idling vibration and engine shake. However, in recent automobiles, engine vibration at an extremely low frequency of about 5 Hz, which is lower than the idling vibration or engine shake, has been a problem. The extremely low frequency engine vibration of about 5 Hz has a relatively high amplitude generated at the time of engine cranking, sudden start of the vehicle, rapid acceleration, or the like. In order to suppress the vibration of extremely low frequency and high amplitude, a liquid in which a dilatant fluid is used as a filling liquid has been devised, and is already known, for example, from Japanese Patent Publication No. 2-55659. However, if such a dilatant fluid is used as it is in a liquid-filled type vibration damping device having a conventional structure as shown in FIG. 4, the effect impairs the vibration damping effect of the engine shake which is a vibration of about 10 Hz. There is a possibility that it acts to make it. In other words, there is a possibility that sufficient damping characteristics cannot be exhibited for an engine shake that is a vibration of about 10 Hz. In order to solve such a problem, the dilatant is designed to exhibit a vibration damping ability against extremely low frequency vibration of about 5 Hz and to obtain a sufficient damping characteristic even for an engine shake. It is an object (problem) of the present invention to provide a liquid-filled type vibration damping device having a fluid.
[0005]
[Means for Solving the Problems]
In order to solve the above problems, the present invention has taken the following measures. That is, a connection fitting attached to the vibrating body side, a holder attached to a member or the like on the vehicle body side, an insulator which is provided between the connection fitting and the holder and has a function of blocking vibration from the vibrating body, and an insulator It provided in series for, and a main chamber and auxiliary chamber is enclosed in a non-compressible fluid, due to engine shake by flowing the said non-compressible fluid in between these main chamber and the auxiliary chamber Regarding a liquid-filled type vibration isolator comprising an orifice for attenuating vibration, an air chamber into which a compressive fluid such as air is introduced, and a diaphragm for separating the air chamber and the sub-chamber, chamber, and an incompressible fluid sealed in the orifice, the vibration of a frequency lower than the engine shake, or dilatant fluid as solidification phenomena of the liquid occurs And the orifice through which the dilatant fluid flows is formed in an annular shape, and the shape of the opening on at least one of the main chamber side and the sub chamber side is changed to the shape of the orifice. A configuration in which the opening cross-sectional shape is larger than the general opening cross-sectional shape is adopted.
[0006]
Also, in the liquid filled type vibration damping device having the dilatant fluid, at least one of the main chamber-side opening and the sub-chamber-side opening of the annular orifice is connected to the opening. A configuration was adopted in which a pool for rectifying (laminarizing) the flow of the flowing fluid was provided.
[0007]
[Action]
By adopting the above configuration, the present invention has the following effects. That is, when the liquid-filled type vibration damping device according to the present invention is attached to a vibrating body such as an engine, the vibration from the vibrating body side is propagated to the insulator made of the rubber-like elastic body via the connection fitting. come. By the way, most of these vibrations, including the engine idling vibration, are absorbed by the vibration action of the insulator or the like and cut off at the insulator. Therefore, various vibrations including the engine idling vibration are cut off at the vibration isolator and are not transmitted to the vehicle body. Also, with respect to an engine shake having a lower frequency (about 10 Hz) than the above-described engine idling vibration, the liquid (fluid) flowing in the orifice is prevented from exhibiting dilatancy. As in the case of the vibration damping device of the type, high attenuation characteristics can be obtained. As a result, the effect of the high damping characteristic suppresses engine shake, which is low-frequency vibration.
[0008]
Next, with respect to these engine idling vibrations or vibrations of an extremely low frequency of about 5 Hz, which is a vibration of a lower frequency than that of an engine shake or the like, the spring constant (spring characteristic) of the vibration isolator is increased, and Extremely low frequency engine vibration is physically suppressed. That is, in the present invention, when the fluid sealed in the main chamber and the sub-chamber is subjected to extremely low-frequency vibration and high-amplitude vibration, the properties of the fluid solidify from a liquid state and become viscous. By making the dilatant fluid flow through the orifice, a high spring constant (high spring characteristic) is obtained with respect to the extremely low frequency vibration of about 5 Hz. I'm trying to make it form. Thereby, the engine vibration of the extremely low frequency of about 5 Hz is suppressed.
[0009]
In the present invention, an opening having an opening cross-sectional shape larger than the general opening cross-sectional shape of the orifice is provided at the inlet of the main chamber and the inlet of the sub-chamber of the orifice. Thereby, when the dilatant fluid flows into the orifice from the main chamber or the sub-chamber with a frequency of about 10 Hz, the flow of the fluid is not disturbed at the inlet and the orifice is smoothly prevented. It will flow inward. That is, the flow into the orifice is rectified, and the fluid flows as a laminar flow through the orifice. Therefore, with respect to the engine shake which is a vibration of about 10 Hz, the flow of the fluid in the orifice becomes smooth, and as a result, a predetermined damping characteristic can be obtained. That is, a sufficient damping characteristic (damping coefficient) that can suppress the engine shake can be obtained.
[0010]
As described above, in the present invention, the fluid flowing through the orifice smoothly flows to the engine shake by the action of the opening having a large opening cross-sectional area provided at the entrance and exit of the orifice. A sufficient damping characteristic (damping coefficient) can be obtained, and at the very low frequency of about 5 Hz and high amplitude vibration, the spring characteristic can be kept high by the action of the dilatant fluid. Become like By such an action, in the present invention, in addition to the engine idling vibration and the engine shake, an extremely low frequency engine vibration of about 5 Hz generated at the time of engine cranking, sudden start or rapid acceleration of the vehicle, or the like. Can also be suppressed.
[0011]
【Example】
An embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the configuration of the present embodiment includes a connection fitting 6 connected to a vibrating body such as an engine, a holder 9 connected to a member or the like on the vehicle body side, and a connection between the connection fitting 6 and the holder 9. An insulator 5 made of a rubber-like elastic body, a main chamber 2 and a sub-chamber 3 which are provided in series below the insulator 5 and are filled with an incompressible fluid (liquid). An orifice 1 through which the liquid as the incompressible fluid flows between the main chamber 2 and the sub-chamber 3, an air chamber 7 into which air as the compressible fluid is introduced, and the air chamber 7 and the sub-chamber 3. It is basically composed of a diaphragm 4 partitioning from the chamber 3.
[0012]
In such a basic configuration, the fluid that is sealed in the main chamber 2 and the sub-chamber 3 and flows through the orifice 1 has a very low frequency and a high amplitude. The so-called dilatant fluid is employed, in which the viscosity of the fluid increases and the solidification of the fluid (liquid) occurs. In particular, in the present embodiment, when vibration of an extremely low frequency of about 5 Hz is input, the solidification phenomenon occurs, and the spring characteristics of the vibration isolator having the dilatant fluid are adjusted to be extremely high. A fluid is enclosed.
[0013]
As shown in FIGS. 1 and 2, the orifice 1 through which the dilatant fluid flows is provided in an annular shape on the periphery of a partition plate 8 that separates the main chamber 2 and the sub chamber 3 from each other. It has a configuration that is As shown in FIG. 1, a portion of the orifice main body 15 which forms a main portion thereof is formed by a general opening cross section having a constant opening cross section. Further, an opening (main chamber side opening) 11 to the main chamber 2 and an opening (sub chamber side opening) 19 to the sub chamber 3 formed at both ends of the orifice body 15 having such a configuration. Is formed so as to have an opening cross-sectional area larger than the general opening cross-section.
[0014]
In such a configuration, in the present embodiment, specifically, as shown in FIGS. 2 and 3, an orifice body 15 having a fixed opening cross-sectional area and formed in an annular shape, and the orifice body 15 A main chamber side opening 11 which is provided at both ends and has an entrance to the main chamber 2 side and has a pool shape, and a sub chamber side opening which has an entrance and exit to the sub chamber 3 side. And a part 19. Each of the main-chamber-side opening 11 and the sub-chamber-side opening 19 having a pool shape has a cross-sectional shape larger than the general opening cross-sectional shape of the orifice body 15. is there. That is, the opening of the orifice body 15 is included in the pool-shaped main chamber-side opening 11 and the sub-chamber-side opening 19. Specifically, as shown by an arrow in FIG. 2, the fluid flowing from the main chamber side opening 11 flows from the orifice body 15 to the sub chamber side opening 19 as shown in FIG. At this time, the flow direction of these openings 11 and 19 is not largely changed. That is, the flow direction of the fluid is set to be only the circumferential direction.
[0015]
Next, an operation mode of the present embodiment having these configurations will be described. That is, when the liquid-filled type vibration damping device as shown in FIG. 1 is attached to a vibrating body such as an engine, vibration from the vibrating body side (not shown) is transmitted from the rubber-like elastic body via the connection fitting 6. To the insulator 5. At the insulator 5, most of the propagated vibrations, including engine idling vibrations, are absorbed and cut off. Further, with respect to an engine shake having a lower frequency (about 10 Hz) than the engine idling vibration, the liquid flowing in the orifice 1 is prevented from exerting dilatancy, and is equivalent to a conventional liquid filled type vibration damping device. High attenuation characteristics are exhibited. By the action of the high damping characteristic, engine shake, which is low-frequency vibration, is suppressed, thereby preventing vibration caused by engine shake from propagating to the vehicle body.
[0016]
Next, the spring constant (spring characteristic) of the engine mount device (anti-vibration device) is determined for an idling vibration or an extremely low frequency vibration of about 5 Hz, which is a frequency one step lower than that of an engine shake or the like. It is set high to physically suppress the extremely low frequency vibration. That is, in the present embodiment, when the fluid (liquid) sealed in the main chamber 2 and the sub-chamber 3 is subjected to very low frequency vibration and high amplitude vibration, the property of the fluid becomes liquid. The dilatant fluid is solidified from the state described above and becomes a state having a high viscosity, that is, a so-called dilatant fluid, and such a dilatant fluid is caused to flow rapidly in the orifice 1 so that the fluid is solidified and the spring characteristics are hardened. I have to. This suppresses engine vibration at an extremely low frequency of about 5 Hz.
[0017]
When such a dilatant fluid is caused to flow rapidly in the orifice 1 or the like generally formed of a curved path, the flow is disturbed near its entrance and exit, which may cause a solidification phenomenon even in an untargeted frequency range. There is. That is, the properties of the dilatant fluid change with respect to the engine shake which is vibration of about 10 Hz, and the viscosity of the dilatant fluid becomes too high, so that it may be difficult to obtain appropriate damping characteristics. Therefore, in the present embodiment, the opening 11 having a larger opening cross-sectional shape (larger opening cross-sectional area) than the general opening cross-sectional shape of the orifice 1 is provided at the main chamber side entrance and the sub-chamber side entrance of the orifice 1. When the dilatant fluid flows into the orifice 1 with a frequency of about 10 Hz from the main chamber 2 side or the sub chamber 3 side, the flow of the fluid is disturbed at the inlet. It does not happen.
[0018]
That is, the flow is not largely changed at the main chamber side opening 11 and the sub chamber side opening 19 which are the entrances and exits of the orifice 1. As a result, the flow of the fluid in the orifice main body 15 and in the vicinity of the main chamber side opening 11 and the sub chamber side opening 19 provided at both ends thereof is laminarized. As a result, the flow of the fluid in the orifice 1 becomes smooth with respect to the engine shake which is a vibration of about 10 Hz, and as a result, a predetermined damping characteristic can be obtained. That is, a sufficient damping characteristic (attenuation coefficient) for suppressing the engine shake is obtained.
[0019]
As described above, in this embodiment, by providing the pool-like openings (the main chamber side opening 11 and the sub chamber side opening 19) having the large opening cross-sectional area at the entrance and exit of the orifice 1, 10 Hz is provided. The fluid flowing through the orifice 1 is made to smoothly flow with respect to the engine shake which is the front and rear vibrations, whereby a sufficient damping characteristic (damping coefficient) is obtained. On the other hand, with respect to a vibration having an extremely low frequency of about 5 Hz and a high amplitude, the spring characteristics can be kept high by the action of the dilatant fluid. This makes it possible to absorb or dampen engine idling vibration and engine shake, and also engine vibration at an extremely low frequency of about 5 Hz.
[0020]
【The invention's effect】
According to the present invention, a connection fitting attached to the vibrating body side, a holder attached to a member or the like on the vehicle body side, and an insulator which is provided between the connecting fitting and the holder and has a function of blocking vibration from the vibrating body is provided. A main chamber and a sub-chamber provided in series with the insulator, and filled with an incompressible fluid, and an orifice for flowing the incompressible fluid between the main chamber and the sub-chamber, With respect to a liquid-filled vibration isolator comprising an air chamber into which a compressive fluid such as air is introduced, and a diaphragm separating the air chamber and the sub-chamber, it is sealed in the main chamber, the sub-chamber, and the orifice. The incompressible fluid to be formed is made of a dilatant fluid in which liquid solidification occurs under a predetermined frequency and under a predetermined amplitude, and the dilatant flow The orifice in which the orifice flows has an annular shape, and the shape of the opening on at least one of the main chamber side and the sub-chamber side is larger than the general opening cross-sectional shape of the orifice. When the dilatant fluid flows through the orifice, the flow of the dilatant fluid is large at the openings of the orifice to the main chamber and the sub-chamber because the dilatant fluid flows at the orifice. No diverting, thereby eliminating disturbances in the fluid flow.
[0021]
Therefore, for the vibration of extremely low frequency of about 5 Hz, the spring characteristic can be hardened by the dilatant effect of the fluid, and the conventional vibration for the engine shake of about 10 Hz can be obtained. It has become possible to obtain the same high attenuation characteristics as those of the liquid filled type vibration damping device. As a result, in the present invention, in addition to the engine idling vibration and the engine shake damping function, the vibration damping function of an extremely low frequency vibration of about 5 Hz can be exhibited.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing the overall configuration of the present invention.
FIG. 2 is a plan view showing an entire configuration around an orifice which forms a main part of the present invention.
FIG. 3 is a front view showing an entire configuration around an orifice constituting a main part of the present invention.
FIG. 4 is a longitudinal sectional view showing the entire configuration of a conventional example.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 orifice 11 main chamber side opening 15 orifice body 19 sub-chamber side opening 2 main chamber 3 sub-chamber 4 diaphragm 5 insulator 6 connecting fitting 7 air chamber 8 partition plate 9 holder

Claims (2)

A connection fitting attached to the vibrator, a holder attached to a member or the like on the vehicle body, an insulator which is provided between the connection fitting and the holder and has a function of blocking vibration from the vibrator, and an insulator for the insulator. The main chamber and the sub-chamber, which are provided in series and are filled with the incompressible fluid, and the non-compressible fluid flows between the main chamber and the sub-chamber, whereby vibration caused by the engine shake is reduced. An orifice that attenuates, an air chamber into which a compressible fluid such as air is introduced, and a diaphragm that partitions the air chamber and the sub-chamber,
The incompressible fluid enclosed in the main chamber, the sub-chamber, and the orifice is made of a dilatant fluid in which a liquid solidification phenomenon occurs under vibration of a frequency lower than that of an engine shake , and the orifice through which the dilatant fluid flows is used. And the shape of the opening on at least one of the main chamber side and the sub-chamber side has an opening cross-sectional shape larger than the general opening cross-sectional shape of the orifice. A liquid-filled type vibration damping device characterized by having such a configuration. A connection fitting attached to the vibrator, a holder attached to a member or the like on the vehicle body, an insulator which is provided between the connection fitting and the holder and has a function of blocking vibration from the vibrator, and an insulator for the insulator. The main chamber and the sub-chamber, which are provided in series and are filled with the incompressible fluid, and the non-compressible fluid flows between the main chamber and the sub-chamber, whereby vibration caused by the engine shake is reduced. An orifice that attenuates, an air chamber into which a compressible fluid such as air is introduced, and a diaphragm that partitions the air chamber and the sub-chamber,
The incompressible fluid enclosed in the main chamber, the sub-chamber, and the orifice is made of a dilatant fluid in which a liquid solidification phenomenon occurs under vibration of a frequency lower than that of an engine shake , and the orifice through which the dilatant fluid flows is used. Is formed in an annular shape, and the flow of the fluid flowing to the opening is rectified at at least one of the main chamber side opening and the sub chamber side opening. A liquid-filled type vibration damping device, characterized in that it has a configuration in which a pool is provided for conversion.

Images