JPH02245536A - Fluid sealing vibrationproofing unit - Google Patents

Abstract

PURPOSE:To increase a loss factor in a low-frequency region for a vibrationproofing unit having a first orifice structure partitioned by first and second liquid chambers by arranging a second orifice structure by which a flow rate in a circular orifice of the first orifice structure is controlled according to the size of a certain orifice diameter length maintained, in the first liquid chamber. CONSTITUTION:When low-frequency vibration of large amplitude is applied between first and second substrates 1, 3, difference in liquid operation is caused between first and second liquid chambers 21, 23, whereby a first orifice structure 11 is fluctuated due to the deformation of a third elastic body 20, and a liquid flow rate in a circular orifice 15 is increased due to a contracted vein effect of an orifice 35d of large diameter in second orifice structure 35, and liquid flows drastically, the liquid in the circular orifice 15 being defined as a primary mass. The low-frequency vibration of large amplitude can thus be absorbed. By varying the length of diameter L of the orifice 35d, resonance frequency of the vibration input between the substrates 1 and 3 can be varied.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a fluid-filled vibration isolating unit used as a support device for a vehicle power unit such as an engine.

BACKGROUND OF THE INVENTION Vibration isolators filled with fluid have been known as support devices for vehicle power units.The static load is supported by a rubber elastic body, and the high-frequency, small-amplitude vibration input transmitted from the power unit is handled by a rubber elastic body. While the vibration input of low frequency and large amplitude is absorbed by the movement of the orifice,
Generally known is a structure in which vibration is damped by a fluid dynamic damper in which the liquid in the orifice is the main mass and the expansion elasticity accompanying the flow of the liquid is used as a spring.

As an example, German Patent No. 3,632,670 discloses the structure of a vibration isolating unit A shown in FIG. In the figure, 1 is a first board fixed to a vibrating body such as a power unit (not shown), and 3 is a second board fixed to a support body such as a vehicle body, and the first board l and the second board 3 are constant. They are located at long distances. Reference numeral 5 denotes a stopper plate fixed along the circumferential direction of the second substrate 3, and a first elastic body 7 forming a liquid chamber therein is applied between the stopper plate 5 and the first substrate l. It is fixed by means such as sulfur adhesion.

Reference numeral 11 denotes an orifice structure for separating the above-mentioned liquid chamber into a first liquid chamber 21 and a second liquid chamber 23. A predetermined flow volume is secured inside this orifice structure 11, and the upper and lower An annular orifice 15 communicating with the orifice structure 11 is formed, and a second elastic body 17 in the form of a film that deforms up and down in accordance with the pressure of the liquid is fixed approximately at the center of the orifice structure 11. A peripheral portion of the orifice structure 11 is fitted and fixed to the partition member 9 fixed to the stopper plate 5 at a fitting portion 13 via a third elastic body 20.

Furthermore, a fourth elastic body 19 formed of a diaphragm or the like is disposed below the orifice structure 11 and defines an end portion of the second liquid chamber 23 and has a peripheral portion fitted to the stopper plate 5. ing.

Further, an air chamber 25 is formed between the fourth elastic body 19 and the second substrate 3.

According to such a configuration, when a high-frequency, small-amplitude vibration displacement is input between the first substrate l and the second substrate 3, the liquid pressure difference between the first liquid chamber 21 and the second liquid chamber 23 decreases. is small, so the second
As the elastic body 17 deforms in the vertical direction according to the liquid displacement, the third elastic body 20 also deforms in the vertical direction, and the first liquid chamber 21
The hydraulic pressure displacement caused by the change in the volume of the liquid chamber due to the displacement of the hydraulic pressure fluctuation is absorbed, and the first and second liquid chambers 21 and 23 maintain the hydraulic pressure between the roads and the vibration towards the vehicle body. Transmission is reduced.

On the other hand, when a low frequency, large amplitude vibrational displacement is input between the first substrate l and the second substrate 3, the first and second liquid chambers 21.2
3, the orifice structure 11 acts as a fluid dynamic damper whose main mass is the liquid in the annular orifice 15 and whose spring is the expansion elasticity of the fourth elastic body 19 as the fluid flows. As a result, the liquid flows vigorously within the annular orifice 15. As a result, among low-frequency, large-amplitude vibrations, vibrations outside the resonant frequency range can be attenuated by the contraction action of the annular orifice 15, while vibrations within the resonant frequency range are damped by the vibrations input by the dynamic damper action. The energy is replaced by liquid flow energy, and vibrations such as engine shake are absorbed.

Problems to be Solved by the Invention However, in the configuration of such a conventional fluid-filled vibration isolating unit, when the excitation frequency transmitted from the vibrating body is in a high frequency region, the second elastic body 17 and If the dynamic spring constant of the third elastic body 20 is made small, vibration transmission from the vibrating body to the vehicle body can be reduced, but on the other hand, if the dynamic spring constant of the elastic body is made small, the vibration attenuation rate in the low frequency region, that is, the loss factor, will decrease. There was a problem with the decline.

Furthermore, the resonance frequency when low-frequency, large-amplitude vibration is input is limited to a preset region, and this resonance frequency cannot be set arbitrarily, so the dynamic spring constant and loss factor in a specific frequency region It has the disadvantage that it cannot be improved. That is, in the low frequency range, as described above, the amount of liquid passing through the annular orifice 15 formed in the orifice structure 11 decreases, and the loss factor decreases, while in the high frequency range, the dynamic spring constant remains approximately constant. , cannot be tuned to any value.

Also, in general, the vibration frequency is 80 to 15 in the high frequency range.
It is known that when the vibration frequency is in the range of 0H2, a muffled engine sound is generated, and when the vibration frequency is in the range of 250 to 400H2, engine combustion noise is generated. In this case, it is not possible to lower both the dynamic spring constants in the above-mentioned image frequency range, and therefore there is a problem that it is not possible to effectively act on both such muffled sound and combustion sound. There is.

Therefore, the present invention solves the problems that such conventional fluid-filled vibration isolating units have, and reduces the dynamic spring constant of each of the elastic bodies to reduce vibration when the excitation frequency is in a high frequency region. Vibration isolation that can reduce vibration transmission from the body to the vehicle body side, increase the loss factor in the low frequency range, and reduce the dynamic spring constant in multiple frequency ranges for high frequency and small amplitude vibrations. The purpose is to provide units.

Furthermore, in the present invention, when the excitation frequency is in the low frequency range,
It is an object of the present invention to provide a vibration isolation unit that can tune the resonance frequency and improve the loss factor.

Means for Solving the Problems In order to achieve the above object, the present invention includes a first substrate fixed to a vibrating body, a second substrate fixed to a support body, and a liquid chamber located between the two substrates. a first elastic body to be formed;
An annular orifice is disposed inside the liquid chamber to ensure a predetermined flow volume and communicate vertically, and a second orifice is formed approximately at the center that deforms vertically according to the pressure of the liquid.
a first orifice structure to which an elastic body is fixed and whose peripheral part is fixed to an inner wall of the liquid chamber via a third elastic body to separate the liquid chamber into a first liquid chamber and a second liquid chamber; a fourth elastic body disposed below the first orifice structure and defining an end portion of the second liquid chamber; and a non-filling body filled in the first liquid chamber and the second liquid chamber. In a fluid-filled vibration damping unit comprising a compressible fluid, a predetermined orifice diameter is maintained in the first liquid chamber, and the first orifice is formed in the first orifice structure depending on the size of the orifice diameter. This is a structure of a fluid-filled vibration damping unit in which a second orifice structure for controlling the flow rate of fluid within the annular orifice is provided.

According to this configuration, the first liquid chamber is further divided into upper and lower liquid chambers by the second orifice structure. It becomes possible to control the flow rate of fluid within the annular orifice formed in the first orifice structure, thereby reducing the dynamic spring constant of each elastic body and reducing vibration transmission in the high frequency range. It is possible to increase the loss factor in the frequency region.In other words, the orifice formed in the second orifice structure causes the loss factor in the first orifice structure to increase when low frequency and large amplitude vibration displacement is input. The liquid flows violently in the annular orifice formed in the cylindrical orifice, and among low-frequency, large-amplitude vibrations, vibrations outside the resonance frequency range, such as engine shake, can be attenuated by the contraction action of the annular orifice.
Vibrations in the resonant frequency region can be absorbed by the dynamic damper action, where the input vibration energy is replaced by liquid flow energy.

Also, the frequency of 80 to 150Hz causes muffled engine noise.
Moderate vibrations can be attenuated by the vertical deformation of the second elastic body and the third elastic body, and the action of the fourth elastic body to absorb fluid pressure fluctuations in the second liquid chamber. 250-400) 1. The degree of vibration is
Attenuation can be achieved by the contraction action of the fluid passing through the wide-diameter orifice formed in the second orifice structure disposed in the first liquid chamber and by the fluid pressure fluctuation absorption action of the third elastic body. .

Furthermore, by changing the diameter length of the orifice formed by the second orifice structure, the overall resonance frequency region moves to the lower frequency side or the higher frequency side, and in the low frequency region, as described above, the resonance frequency region moves to the lower frequency side or the higher frequency side. The orifice structure of the annular orifice does not swing, and therefore the amount of liquid passing through the annular orifice increases, making it possible to increase the loss factor.

EXAMPLE Hereinafter, an example of a fluid-filled vibration isolating unit according to the present invention will be described in detail, with the same reference numerals attached to the same components as those of the conventional structure.

In the configuration shown in FIG. 1, 1 is a first substrate fixed to a vibrating body (not shown), and 3 is a second substrate fixed to a support such as a vehicle body.
The first substrate 1 and the second substrate 3 are arranged in advance to be separated by a certain length, and fixing stud bolts 31 and 33 are respectively attached. 5 is a stopper plate fixed along the circumferential direction of the second substrate 3, and between the stopper plate 5 and the first substrate l,
A first elastic body 7 for forming a liquid chamber inside is fixed by vulcanization adhesive means.

Reference numeral 11 denotes a first orifice structure for separating the liquid chamber into a first liquid chamber 21 and a second liquid chamber 23. An annular orifice 15 that secures a volume and communicates vertically is formed, and at approximately the center of the first orifice structure 11, a second elastic member that moves vertically within a regulated range according to the pressure of the liquid is formed. The body 17 is fixed. This second elastic body 17 has a spindle cross-sectional shape with spherical upper and lower surfaces, is thickest at the center, and has a fitting portion 1 provided at the outer periphery.
7a is fitted and fixed to the first orifice structure ll.

Further, the peripheral portion of the first orifice structure 11 is fitted and fixed to the partition member 9 fixed to the stopper plate 5 via a third elastic body 20.

For example, as seen in the plan view of FIG. 2, the annular orifice 15 is formed so as to make approximately one turn in the circumferential direction inside the first orifice structure 11, and is actually connected to the upper communication hole. 15a and the lower communication hole 15b are in an adjacent positional relationship.

Further, at the lower part of the first orifice structure 11, there is a fourth elastic body 19 formed of a diaphragm or the like that defines the end portion of the second liquid chamber 23 and whose local portion is fitted to the stopper plate 5. It is located. Further, the fourth elastic body 1
An air chamber 25 is formed between the second substrate 9 and the second substrate 3 .

Furthermore, in the case of the present invention, on the inner surface of the stopper plate 5,
The first liquid chamber 21 is fitted and fixed together with the partition member 9.
A second orifice structure 35 extending laterally is fitted. The second orifice structure 35 includes a base portion 35a fixed to the stopper plate 5, an upwardly rising portion 35b, and a first portion extending from the tip of the rising portion 35b.
The first liquid chamber 21 has an extended portion 35c extending toward the center of the first liquid chamber 21, and a wide-diameter orifice 35d is formed inside the first liquid chamber 21. There is. Therefore, the wide-diameter orifice 35d substantially divides the first liquid chamber 21 into upper and lower liquid chambers.

The first liquid chamber 21 and the second liquid chamber 23 are filled with an incompressible fluid such as antifreeze.

Incidentally, on the lower surface of the first substrate l, a stopper plate 39 having a rubber film 37 fixed to the surface is provided on the bottom surface of the stud bolt 31.
is fixed in the first liquid chamber 21 in a slightly projecting state.

The diameter length of the wide-diameter orifice 35d formed by the second orifice structure 35 can be changed arbitrarily, and by changing this diameter length, the first orifice structure 11 can be By controlling the flow rate of fluid within the formed annular orifice 15, the resonance frequency of the vibration input between the first substrate 1 and the second substrate 3 can be made variable.

The operation of the fluid-filled vibration isolating unit having such a configuration will be explained below. In other words, as a basic operating mode, first
When a low-frequency, large-amplitude vibration around 1 OHZ is applied between the substrate 1 and the second substrate 3 due to engine shake or the like with an amplitude of about 1 mm, a large vibration occurs between the first and second liquid chambers 21 and 23. When a hydraulic pressure difference is caused and the first orifice structure 11 swings greatly due to the deformation of the third elastic body 20, the wide-diameter orifice 35d formed in the second orifice structure 35 opens. The flow rate of the fluid in the annular orifice 15 increases based on the contraction action of the annular orifice 15, and the liquid in the annular orifice 15 is used as the main mass, and the expansion elasticity of the fourth elastic body 17 accompanying the flow of the fluid is used as a spring. Due to the action of the fluid dynamic damper, the liquid flows vigorously within the annular orifice 15. As a result, among low frequency and large amplitude vibrations, vibrations outside the resonant frequency range are transmitted through the annular orifice 15.
On the other hand, vibrations in the resonant frequency region can be absorbed by the dynamic damper action, where input vibration energy is replaced by liquid flow energy.

Next, between the first board l and the second board 3, the amplitude, which causes engine muffled noise, is approximately 0.05 mm and 80 to 15 mm.
When vibration within the range of 0Hz is applied, the first liquid chamber 21
Since the liquid pressure difference between the liquid chamber 23 and the second liquid chamber 23 is small, the second elastic body 17 and the third elastic body 20 deform in the vertical direction according to the liquid displacement, and at the same time, the fourth elastic body 19 deforms the liquid in the second liquid chamber 23. Absorbs pressure fluctuations. Therefore, the second elastic body 17 and the third elastic body 2
No hydraulic pressure displacement occurs due to the change in the volume of the liquid chamber due to the deformation of the 0, and the first and second liquid chambers 21 and 23 maintain the hydraulic pressure between the roads, and vibrations are not transmitted to the vehicle body. Reduced.

Furthermore, between the first substrate 1 and the second substrate 3, the amplitude, which causes combustion noise of the engine, is approximately 0.01 mm and 250 to 40 mm.
When high-frequency, small-amplitude vibration within the range of 0H2 is applied, the annular orifice 15 and the second elastic body 17 hardly act, and the second orifice disposed in the first liquid chamber 21 Attenuation can be achieved by the contraction effect of the fluid passing through the wide-diameter orifice 35d formed by the structure 35. In other words, the first liquid chamber 21 is further divided into upper and lower liquid chambers by the wide-diameter orifice 35d, and when the flow is contracted by this orifice 35d, the third
The elastic body 20 acts to absorb this fluid pressure fluctuation.

Therefore, based on the action of the second orifice structure 35, vibrations that cause engine combustion noise can be absorbed.

During the above action, the wide diameter orifice 35d described above
If the diameter length of the wide-diameter orifice 35d is increased, the overall resonant frequency range will move in a direction that becomes higher, and if the diameter length of the wide-diameter orifice 35d is made smaller (then the overall resonant frequency range will move in a direction that becomes lower). As described above, in the low frequency range, the first orifice structure 11 does not swing, and therefore the amount of liquid passing through the annular orifice 15 increases, making it possible to increase the loss factor. The dynamic spring constant of can be tuned to a low value. That is, liquid column resonance is generated by the expansion spring of the third elastic body 20, the expansion spring of the first elastic body 7, and the diameter length of the orifice 35d. , the vibration transmission force in the high frequency range is reduced.

FIG. 3 is a graph showing actual measured values of the loss factor and dynamic spring constant of the anti-vibration unit a according to the present invention, and similar actual measured values of the conventional anti-vibration unit b, as shown in FIG. The vibration unit has a larger loss factor in the low frequency range compared to the conventional model, while the dynamic spring constant in the high frequency range is smaller than that of the conventional model (in the region shown in X). Moreover, compared to the conventional vibration isolation unit where the vibration frequency at which the dynamic spring characteristics can be reduced is at one place, in the case of the present invention, the vibration frequency at which the dynamic spring characteristics can be reduced is at the above-mentioned X. ,.

There are two locations as shown in the area indicated by X, proving that the overall vibration damping performance has been improved.

Further, according to the above configuration, by changing the diameter length of the wide-diameter orifice 35d formed by the second orifice structure 35, the overall resonant frequency region is moved to the lower frequency side or the higher frequency side. At the same time, in the low frequency region, as described above, the first orifice structure 1
1 does not swing, and therefore the amount of liquid passing through the annular orifice 15 increases, making it possible to increase the loss factor, while reducing the dynamic spring constant in the high frequency region at multiple locations. Thus, a fluid-filled vibration isolation unit having desired vibration reduction characteristics is provided.

Effects of the Invention As explained in detail above, according to the fluid-filled vibration isolating unit according to the present invention, the first substrate fixed to the vibrating body, the second substrate fixed to the support body, and the A first elastic body that forms a liquid chamber therein, an annular orifice placed inside the liquid chamber that communicates vertically while ensuring a predetermined flow volume, and a liquid pressure control member located approximately at the center of the body. A second elastic body that deforms up and down in response to a first orifice structure separated from the first orifice structure; a fourth elastic body disposed below the first orifice structure and defining an end portion of the second liquid chamber; In a fluid-filled vibration isolating unit consisting of an incompressible fluid filled in a second liquid chamber, a predetermined orifice diameter is maintained in the first liquid chamber, and the orifice diameter is adjusted depending on the size of the orifice diameter. Since the fluid-filled vibration isolation unit is configured with a second orifice structure that controls the flow rate of fluid within the annular orifice formed in the first orifice structure, the following effects can be achieved. brought about. That is, since the first liquid chamber is further divided into upper and lower liquid chambers by the second orifice structure, the first orifice structure It is possible to control the flow rate of fluid within the annular orifice formed in the body, reducing the dynamic spring constant of each elastic body (thus reducing vibration transmission in the high frequency range and reducing loss in the low frequency range). It becomes possible to increase the factor.

That is, when a low-frequency, large-amplitude vibrational displacement is input through the orifice formed in the second orifice structure, the liquid flows violently within the annular orifice formed in the first orifice structure, causing a low Among vibrations with large frequency amplitudes, vibrations outside the resonant frequency region such as engine shake can be attenuated by the contraction action of the annular orifice, while vibrations in the resonant frequency region are damped by the input vibration energy due to the dynamic damper action. Vibrations can be absorbed by being replaced by liquid flow energy.

Furthermore, in the case of the present invention, 8
Although slight vibrations of the order of O-150H can be attenuated by the vertical deformation of the second and third elastic bodies and the action of the fourth elastic body to absorb fluid pressure fluctuations in the second liquid chamber, The vibrations of about 250 to 400 Hz, which cause combustion noise, are caused by the contraction effect of the fluid passing through the wide-diameter orifice formed in the second orifice structure disposed in the first liquid chamber, and the third orifice. Attenuation can be achieved by the action of the elastic body to absorb fluid pressure fluctuations. Therefore, it is possible to reduce the dynamic spring constants at multiple locations, including the vibration frequency where muffled engine noise is likely to occur and the vibration frequency where engine combustion sound is likely to occur, even in the high frequency range. A great effect is obtained in that a vibration isolating unit that is effective against both combustion noise and combustion noise is provided.

Furthermore, by changing the diameter length of the orifice formed by the second orifice structure, it is possible to move the overall resonant frequency region to the lower frequency side or to the higher frequency side. In this region, as described above (the first orifice structure does not oscillate, the amount of liquid passing through the annular orifice increases, improving the dynamic spring constant and loss factor in a specific frequency region). This has the unique effect of making it possible to

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a main part showing an embodiment of a fluid-filled vibration isolating unit according to the present invention, FIG. 2 is a cross-sectional view taken along the line ■-■ in FIG. 1, and FIG. FIG. 4 is a graph showing the measured values of the vibration damping properties of the vibration damping unit and the conventional product. FIG. 4 is a sectional view of a main part showing an example of a conventional fluid filled vibration damping unit. l...first substrate, 2...second substrate, 5...stopper plate, 7...first elastic body, 9...partition member,
ll...(first) orifice structure, 15...annular orifice, 17...second elastic body, 19...fourth
Elastic body, 20... Third elastic body, 21... First liquid chamber, 23... Second liquid chamber, 25... Air chamber, 35...
・(Second) orifice structure, 35d... (wide diameter) orifice, 4.

Claims (1)

[Claims] (1) A first substrate fixed to the vibrating body, a second substrate fixed to the support body, a first elastic body located between the two substrates and forming a liquid chamber inside, and a first elastic body disposed inside the liquid chamber. An annular orifice is formed which communicates vertically by securing a predetermined flow volume, and a second elastic body that deforms vertically according to the pressure of the liquid is fixed to the approximately center position, and a third elastic body is fixed to the circumferential part. a first orifice structure fixed to the inner wall of the liquid chamber via an elastic body to separate the liquid chamber into a first liquid chamber and a second liquid chamber; a fluid-filled vibration damper comprising a fourth elastic body arranged to define an end portion of the second liquid chamber; and an incompressible fluid filled in the first liquid chamber and the second liquid chamber. In the unit, a predetermined orifice diameter length is maintained in the first liquid chamber, and the flow rate of fluid within the annular orifice formed in the first orifice structure is controlled depending on the size of the orifice diameter length. A fluid-filled vibration isolating unit characterized in that a second orifice structure is disposed therein.