JP4124326B2 - Active liquid seal vibration isolator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid ring vibration isolator used for an engine mount for automobiles and the like, and relates to an active liquid ring vibration isolator that cancels input vibration by generating vibrations having substantially the same phase by a vibration means.
[0002]
[Prior art]
Such an active liquid seal vibration isolator is known (see, for example, JP-A-9-53678). A general structure of such an active liquid seal vibration isolator is configured such that a part of the wall of the main liquid chamber is constituted by a conical rubber insulator, and vibration is input from the top of the insulator and is partitioned by a partition wall. In addition, a vibration member that is floated and supported by an elastic seal is provided in a vibration chamber that communicates with the vibration chamber to generate vibration in the vibration chamber that has substantially the same phase as the vibration to be input to the main liquid chamber. ing. In addition, an elastic film is provided on the partition wall so as to absorb the fluid pressure fluctuation in the main fluid chamber.
[0003]
[Problems to be solved by the invention]
By the way, the vibration member as in the above-described conventional example is generally vibrated only with respect to vibration to be vibrated at a specific frequency and is free at other frequencies. Vibrates together with an elastic seal that is elastically deformed in response to the vibration (hereinafter, when the vibration is applied is referred to as active, and when the vibration is not applied is referred to as non-active or passive). However, unlike a simple diaphragm, an elastic seal has an inherent spring value that is somewhat large, so that when it is passive, a peak of the dynamic spring constant due to its membrane resonance occurs. For example, when the conventional example shown in FIG. 2 is tuned so that the membrane resonance of the elastic seal occurs at about 80 Hz and the dynamic spring constant peak P2 due to the anti-resonance occurs at about 100 Hz, about 80 Hz. If the vibration in the lower frequency range is set to vibration to be prevented by active control, and if an effective active characteristic is to be exhibited only in this frequency range, the peak P2 of the dynamic spring constant generated at about 100 Hz is obtained. Will remain.
[0004]
This peak P2 of the dynamic spring constant is in a relatively higher frequency range than the vibration to be damped at the time of starting or the like, and affects noise and vibration, so it is preferable to eliminate it. On the other hand, such a peak P2 of the dynamic spring constant can be eliminated by making the spring value of the elastic seal smaller. However, in order to maintain the active performance, the spring value cannot be reduced so much, and the durability, etc. Because there are tradeoffs, the tuning range is inherently narrow.
[0005]
Therefore, it is desired to effectively remove the peak of the dynamic spring constant caused by the membrane resonance of the elastic seal with a simple and wide tuning width without changing the elastic seal. The object of the present invention is to realize such a demand.
[0006]
[Means for Solving the Problems]
In order to solve the above-described problem, the active liquid seal vibration isolator according to claim 1 of the present application includes a main liquid chamber having a wall part of an insulator that connects the first mounting member and the second mounting member. The main liquid chamber communicates with the vibration chamber, and a vibration member is provided in the vibration chamber to generate vibration substantially in phase with vibration to be input to the main liquid chamber. In a liquid seal vibration isolator in which the periphery of a member is floatingly supported by an elastic seal, a throttle passage is provided in a partition wall that divides the vibration chamber and the main liquid chamber, and the diaphragm passage and the vibration member are partitioned. An elastic membrane is provided, and a small liquid chamber communicating with the main liquid chamber only through the throttle passage is formed between the elastic membrane and the partition wall, and the elastic membrane is formed more than an opening area of the throttle passage. Characterized by being enlarged .
[0007]
According to a second aspect of the present invention, in the first aspect, the vibration member vibrates only the vibration to be vibrated at a specific frequency and vibrates by elastic deformation of the elastic seal with the vibration member being free at other frequencies. It is characterized by doing so.
[0008]
A third aspect of the present invention is characterized in that, in the first aspect, the small liquid chamber and the vibration chamber are not in communication with each other with the elastic film interposed therebetween.
[0009]
According to a fourth aspect of the present invention, in any one of the first to third aspects, the elastic film has a non-linear spring characteristic.
[0010]
A fifth aspect of the present invention is characterized in that, in the first aspect, the elastic film is attached by removing an initial strain generated at the time of molding.
[0011]
【The invention's effect】
According to the first aspect, when the change in the hydraulic pressure in the main liquid chamber is transmitted to the vibration chamber, the restriction passage is provided in the partition wall disposed between the main liquid chamber and the vibration chamber. The passage reduces the energy to be transmitted from the main liquid chamber to the vibration chamber. In addition, since an elastic film is disposed between the throttle passage and the vibrating member, the elastic film absorbs the change in the hydraulic pressure in the main liquid chamber. For this reason, the membrane resonance energy of the elastic seal due to the fluid pressure fluctuation in the main fluid chamber is reduced, and the peak of the dynamic spring constant due to the membrane resonance of the elastic seal can be removed or suppressed.
[0012]
In addition, the elastic seal has its rigidity (hereinafter referred to as wall rigidity) set to balance active performance and durability. By freely setting the spring constant of the elastic membrane and the opening diameter of the throttle passage without changing it, the membrane resonance of the elastic seal can be controlled within a range that does not affect the active performance. The peak of the dynamic spring constant can be removed or suppressed, and a wider tuning range is possible.
[0013]
According to claim 2, even when active and passive coexist, and even when a dynamic spring constant peak caused by membrane resonance of the elastic seal may occur during passive, it is caused by membrane resonance of this elastic seal. The peak of the dynamic spring constant can be removed or suppressed.
[0014]
According to the third aspect, since the main liquid chamber and the vibration chamber are completely separated by the small liquid chamber and the elastic membrane, the main liquid chamber and the vibration chamber 7 have a non-communication structure. Since the fluid pressure fluctuation on the chamber side is always transmitted to the vibration chamber side via the throttle passage and the elastic membrane, it is possible to avoid the fluid pressure fluctuation on the main fluid chamber side being directly transmitted to the elastic seal.
[0015]
According to the fourth aspect, since the elastic film has a non-linear spring characteristic, it can be changed to an optimum spring value according to the magnitude of the input vibration.
[0016]
According to the fifth aspect, by attaching the elastic film while removing the initial strain generated at the time of molding, the stress at the time of molding can be released and a preset spring characteristic can be realized.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment will be described below with reference to the drawings. FIG. 1 shows an entire cross section of an automotive engine mount as an embodiment, and FIG. 2 is a graph showing its dynamic spring characteristics. In FIG. 1, the engine mount 1 includes a first attachment member 2 attached to the engine side (not shown), a second attachment member 3 attached to the vehicle body side (not shown), and an insulator interposed therebetween.
[0018]
The insulator 4 is an anti-vibration elastic body such as an anti-vibration rubber made of an appropriate elastic material such as rubber, has a predetermined spring constant for absorbing input vibration from the first mounting member 2, and is substantially as a whole. It has a conical shape, and the first mounting member 2 is integrated at the top, and the periphery of the skirt is connected to the second mounting member 3.
[0019]
A liquid chamber in which an incompressible liquid is sealed is formed between the first mounting member 2, the second mounting member 3, and the insulator 4, and the main liquid chamber on the insulator 4 side is formed by a partition wall 5 provided therein. 6 and an excitation chamber 7 on the opposite side across the partition wall 5.
[0020]
A throttle passage 8 is formed at the center of the partition wall 5 facing the main liquid chamber 6, and the insulator 4 faces the main liquid chamber 6 to form a part of the wall of the main liquid chamber 6. An elastic membrane 10 is disposed in the vicinity of the throttle passage 8 on the side of the vibration chamber 7 of the partition wall 5, partitioning the main liquid chamber 6 and the vibration chamber 7, and a small liquid chamber between the partition wall 5. 11 is formed. The small liquid chamber 11 communicates with the main liquid chamber 6 which is the outside only by the throttle passage 8. The surface of the elastic membrane 10 opposite to the small liquid chamber 11 faces the vibration chamber 7. The change in the hydraulic pressure in the main liquid chamber 6 is transmitted to the small liquid chamber 11 only through the throttle passage 8 and further through the elastic deformation of the elastic membrane 10.
The elastic film 10 is a disk-like member having a substantially circular shape when viewed from the main vibration direction Z side of vibrations to be vibrated, and the center thereof coincides with the center line C of the throttle passage 8. The projected area in the Z direction is larger than the opening area of the throttle passage 8 and covers the lower side of the throttle passage 8 in the figure.
[0022]
A vibration plate 12 is provided at the bottom of the vibration chamber 7 facing the elastic film 10. The vibration plate 12 also has a disk shape when viewed from the main vibration direction Z, and its periphery is attached to the second attachment member 3 by an elastic seal 13 and is supported floatingly. The elastic seal 13 allows vibration of the vibration plate 12 and prevents liquid leakage from the vibration chamber 7.
[0023]
The vibration plate 12 is substantially cup-shaped, and the outer peripheral portion of the vibration plate 12 that forms the peripheral wall portion and the elastic seal 13 are baked and integrated, and the insert 13 a integrated on the outer peripheral portion together with the partition wall 5 is an insulator. 4 and the caulking part of the 2nd attachment member 3 are being fixed.
[0024]
The vibration plate 12 is vibrated downward in the figure by an appropriate actuator 15 such as a solenoid via a rod 14 to generate a liquid flow in the vibration chamber 7. The driving of the actuator 15 is controlled by a control device 16 such as a microcomputer. The vibration plate 12, the seal 13, the actuator 15, and the control device 16 constitute a vibration means.
[0025]
The insulator 4 and the elastic seal 13 function as a series input spring, and the throttle passage 8 can obtain a predetermined resonance frequency (for example, 80 to 100 Hz) in the main liquid chamber 6 by vibration input to the insulator 4 and the elastic seal 13. Set the opening diameter as follows. As an example, when the spring value of the insulator 4 is 20 kg / mm and the spring value of the elastic seal 13 is 60 kg / mm, the opening diameter of the throttle passage 8 is 20φ and the resonance frequency is about 80 Hz. However, such a spring combination setting can be arbitrarily set according to the target specification.
[0026]
When the vibration plate 12 is vibrated in substantially the same phase with respect to the vibration input to the first attachment member 2, a liquid flow is generated in the vibration chamber 7. At this time, when the hydraulic pressure in the main liquid chamber 6 rises due to vibration input (hereinafter referred to as positive input), the vibration means of the present embodiment moves the vibration plate 12 downward in the drawing by the actuator 15 to When the pressure increase is canceled and the liquid pressure in the main liquid chamber 6 decreases (hereinafter referred to as negative input), the actuator 15 is released and the vibration plate 12 is moved by the elastic force of the return spring or the elastic seal 13. It functions as a pull type that returns upward in the figure and suppresses fluctuations in the hydraulic pressure in the main liquid chamber 6.
[0027]
The partition wall 5 has a hollow ring shape, and the inside forms a damping orifice passage 17. A part of the damping orifice passage 17 communicates with the main liquid chamber 6 through the opening 18, and the other end of the damping orifice passage 17 is formed on the outer peripheral portion of the second mounting member 3 from the outlet 19 formed on the side wall of the second mounting member 3. It communicates with the liquid chamber 20. A diaphragm 22 is provided in the housing 21 that constitutes the secondary liquid chamber 20, and compensates for the liquid volume fluctuation in the secondary liquid chamber 20 to follow the volume fluctuation of the main liquid chamber 6. The surface of the diaphragm 22 opposite to the sub liquid chamber 20 side is open to the atmosphere.
[0028]
A partition portion 23 extending in a direction orthogonal to the center line C is formed at the center portion of the partition wall 5, and a throttle passage 8 is formed at the center thereof. The partition portion 23 partially covers the upper side of the small liquid chamber 11 in the drawing except for the throttle passage 8 portion. The areas of the elastic film 10 and the vibration plate 12 are approximately the same.
[0029]
The partition wall 5 forms an inclined surface projecting toward the partition line 23 in the direction of the center line C. The opening areas of the openings 24 and 25 on the main liquid chamber 6 and the excitation chamber 7 side are the elastic membrane 10 and the excitation vibration. It is larger than the plate 12.
The opening 25 and the outer peripheral portion of the elastic seal 13 form a substantially wedge-shaped space in the illustrated state.
[0030]
A small communication port 25 a is formed in the opening 25, and the damping orifice passage 17 and the vibration chamber 7 are communicated. The communication port 25a is for allowing a part of the liquid in the vibration chamber 7 to escape to the damping orifice passage 17 side, and the resonance frequency is several Hz, which is considerably lower than the resonance frequency of the damping orifice passage 17. It is a fine hole and has little effect on dynamic spring characteristics.
[0031]
The elastic film 10, the throttle passage 8 and the vibration plate 12 are arranged in a straight line in the vertical direction in the figure so that the respective centers coincide with each other in the main vibration direction Z, that is, on the center line C of the throttle passage 8.
[0032]
A cylindrical hole 26 for accommodating the elastic film 10 is formed on the center side of the partition wall 5 and below the throttle passage 8. A ring in which the outer peripheral portion of the elastic film 10 is integrated with the inner wall of the hole 26. 27 is press-fitted. The central side of the elastic film 10 forms a thick portion 28 and the outer peripheral side forms a thin portion 29 and is connected to the ring 27. Due to such a change in thickness, the elastic film 10 undergoes nonlinear elastic deformation.
[0033]
Note that the elastic membrane 10 is attached in a state of being slackened in advance by reducing the diameter of the ring 27 before being attached and then fixing the ring 27 to the inner wall of the hole 26. In this way, it is possible to release the stress of the elastic film 10 due to the initial strain when the elastic film 10 is molded and baked onto the ring 27, and the initial spring characteristics can be realized accurately. However, the diameter can be reduced when the ring 27 is press-fitted into the inner wall of the hole 26 and fixed. Moreover, it is not necessary to reduce the diameter so that the elastic film 10 can be loosened as long as the initial strain is removed.
[0034]
Next, the operation of this embodiment will be described. At the time of activation, when an idle vibration of about 30 Hz, for example, is input to the first mounting member 2 as a vibration to be isolated, the actuator 15 causes the rod 14 to have substantially the same phase and the same frequency as the vibration to be isolated to cancel the vibration. The vibration plate 12 is vibrated.
[0035]
On the other hand, in the passive state, the actuator 15 makes the vibration plate 12 free with respect to vibration inputs other than vibration to be vibration-proof, so that the elastic seal 13 that floats and supports the vibration plate 12 is provided from the main liquid chamber 6. By elastically deforming according to the transmitted hydraulic pressure change of the vibration chamber 7, the vibration plate 12 moves in the vertical direction in the figure together with the elastic deformation of the elastic seal 13.
[0036]
At this time, the energy accompanying the change in the liquid pressure in the main liquid chamber 6 is first throttled in the passage 23 and further throttled in the throttle passage 8, so that it is reduced and transmitted to the small liquid chamber 11, and the elastic deformation of the elastic film 10 is caused. Make it smaller. Further, the hydraulic pressure fluctuation transmitted from the main liquid chamber 6 to the small liquid chamber 11 through the throttle passage 8 is absorbed by the elastic deformation of the elastic membrane 10. As a result, the fluid pressure fluctuation in the main fluid chamber 6 is not directly transmitted to the elastic seal 13 but is transmitted with the energy of the input vibration being reduced, so that the membrane resonance energy of the elastic seal is reduced. The peak of the dynamic spring constant resulting from is eliminated or suppressed, and is not problematic in practical use.
[0037]
Moreover, the transmission of the fluid pressure fluctuation from the vibration chamber 7 to the main fluid chamber 6 side can be efficiently transmitted to the main fluid chamber 6 by providing the throttle passage 8, and the drive energy of the actuator 15 is reduced. it can.
[0038]
As shown in FIG. 2, in this embodiment, for example, a bottom B1 of the dynamic spring constant due to the membrane resonance of the elastic seal occurs at about 80 Hz, and a peak P1 of the dynamic spring constant due to the anti-resonance occurs at about 100 Hz. If the active control is performed from, for example, about 20 Hz to 80 Hz after the shake vibration frequency range (for example, a range of about 5 to 10 Hz), and inactive control is performed at other frequencies, the active control region has a very low movement. Although the spring is springed and the dynamic spring constant is constant, the peak P1 of the dynamic spring constant to be removed remains at a frequency of about 100 Hz in the non-active control region.
[0039]
However, the peak P1 of the dynamic spring constant is remarkably reduced from the peak P2 of the conventional dynamic spring constant. The difference in the dynamic spring constant is due to the presence of the throttle passage 8 and the elastic film 10 described so far. The conventional example corresponds to the engine mount 1 of the present embodiment except the throttle passage 8 and the elastic membrane 10. In the case of the conventional example, since the membrane resonance in the elastic seal 13 becomes strong, the bottom B2 of the dynamic spring constant is lower, and conversely, the peak P2 of the dynamic spring constant due to antiresonance is higher.
[0040]
The present embodiment is an example in which active control and inactive control (passive) are used in combination. However, it is free to perform active control by expanding the entire frequency range or higher frequency range and lower frequency range than the above embodiment. If the active control range is expanded to a frequency exceeding about 100 Hz, the peak P1 of the dynamic spring constant can be removed. However, when the frequency range of the active control is expanded in this way, the energy consumption for driving the vibration plate 12 to remove the peak P1 of the dynamic spring constant increases, and this is practically used when a solenoid is used as the actuator. Is in a difficult situation.
[0041]
Therefore, considering the use of a practical level of solenoid, it may be advantageous to use active control up to about 80 Hz as in the embodiment and inactive control on the higher frequency side. When the active control range is expanded to a frequency exceeding about 100 Hz, the problem of the actuator remains. However, even in this case, the energy consumption is reduced as compared with lowering the peak P2 of the dynamic spring constant in the conventional example.
[0042]
Further, since the elastic film 10 is given a non-linear spring characteristic, when a relatively small vibration (for example, an amplitude of about 0.03 to 0.1 mm) is input to the insulator 4, the elastic film 10 is received by a weak spring. On the other hand, when a relatively large vibration (for example, an amplitude of about 0.1 to 1 mm) is input on the lower frequency side, the elastic film 10 is received by a strong spring, so that the wall rigidity of the main liquid chamber 6 is increased and the main liquid is increased. The flow rate of the liquid fed from the chamber 6 to the damping orifice passage 17 is increased.
[0043]
For this reason, the resonance efficiency in the damping orifice passage 17 is increased, and in this embodiment, a high attenuation is realized in the shake vibration frequency range (for example, a range of about 5 to 10 Hz) to absorb relatively large vibration. B3 is the bottom of the dynamic spring constant due to the orifice resonance at this time, and P3 is the peak of the dynamic spring constant due to the anti-resonance. In the case of the conventional example in which the elastic film 10 is not given nonlinear characteristics, the bottom of the dynamic spring constant is B4 higher than B3, and the peak of the dynamic spring constant due to antiresonance is P4 lower than P3.
[0044]
Therefore, if the spring of the elastic film 10 is made nonlinear, the spring value of the elastic film 10 can be optimized according to the input vibration, and the resonance efficiency of the damping orifice passage 17 in the low frequency region can be improved.
[0045]
Thus, noise and vibration can be improved by effectively eliminating or suppressing the peak P2 of the dynamic spring constant caused by the membrane resonance of the elastic seal 13 that has occurred in the conventional passive state. Further, the active control can be performed so as to include the frequency region where the peak P2 of the dynamic spring constant is generated. In this case, the driving energy consumption during the active control can be saved by the difference between the dynamic spring constants P2 and P1.
[0046]
In addition, the elastic seal 10 has its wall rigidity set in consideration of active and durability, etc., and the tuning width is inherently narrow, but the elastic seal 13 is not changed. This tuning can be realized by setting the spring constant of the elastic membrane 10 and the opening diameter of the throttle passage 18, and such tuning has a high degree of freedom.
[0047]
Therefore, the membrane resonance of the elastic seal 13 can be controlled in a state where the active performance is less affected, and as a result, the peak of the dynamic spring constant caused by the membrane resonance of the elastic seal 13 can be removed or suppressed more easily and effectively. it can. Moreover, efficient vibration isolation is possible and a wider tuning range is possible. In addition, the actuator 15 can have a relatively small output, and contributes to the reduction in size and weight of the entire apparatus.
[0048]
In addition, the wall surface of the partition wall 5 facing the main liquid chamber 6 is inclined toward the peripheral portion of the throttle passage 8 , and the wall surface of the partition wall 5 facing the vibration chamber 7 is inclined toward the elastic film 10. since the inclined surface, both the liquid flow toward the throttle passage 8 from the liquid flow and reverse oscillating chamber 7 toward the throttle path 8 from the main liquid chamber 6 can smoothly guided, efficient transmission of the hydraulic change Is possible.
[0049]
Further, since the main liquid chamber 6 and the vibration chamber 7 are completely separated by the small liquid chamber 11 and the elastic membrane 10, the main liquid chamber 6 and the vibration chamber 7 have a non-communication structure. Since the fluid pressure fluctuation on the chamber side is always transmitted to the vibration chamber 7 side through the throttle passage 8 and the elastic membrane 10, it is possible to avoid the fluid pressure fluctuation on the main fluid chamber 6 side being directly transmitted to the elastic seal 13. .
[0050]
Further, since the elastic film 10 has a non-linear spring characteristic, it can be changed to an optimal spring value according to the magnitude of the input vibration.
[0051]
Furthermore, by removing the initial strain generated during the molding of the elastic film 10 and attaching it, the stress during the molding can be released and a preset spring characteristic can be realized.
[0052]
In addition, since the partition wall 5 is provided with a small hole 25a for allowing the liquid in the vibration chamber 7 to escape from the vibration chamber 7, the liquid in the vibration chamber 7 can be removed when necessary, such as when the vibration chamber 6 becomes hot. A part of the pressure is released to the damping orifice passage 17 and further to the auxiliary liquid chamber 20 and the like, and the pressure increase in the vibration chamber 7 can be prevented. Further, since the resonance frequency of the small hole 25a is set lower than the resonance frequency of the damping orifice passage 17, it is possible to hardly affect the vibration isolation characteristics (dynamic characteristics) of the apparatus. The communication destination of the small hole 25a, that is, the counterpart side that escapes from the vibration chamber 7 is not limited to this embodiment and can be freely set.
[0053]
The present invention is not limited to the above-described embodiments, and various modifications and applications are possible. The present invention can be used as a vibration isolator for vibration isolation in various vibration transmission paths other than the engine mount. It can also be used as a vibration damper by being attached to a vibration source.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an engine mount according to an embodiment. FIG. 2 is a graph showing an operation.
1: engine mount, 2: first mounting member, 3: second mounting member, 4: insulator, 5: partition wall, 6: main liquid chamber, 7: vibration chamber, 10: elastic membrane, 11: small liquid chamber , 12: vibration plate, 15: actuator, 17: damping orifice passage, 20: auxiliary liquid chamber, 26: hole

Claims (6)

A main liquid chamber having an insulator that connects between the first mounting member and the second mounting member as a part of a wall portion is provided, the main liquid chamber and the vibration chamber are communicated, and the main liquid chamber is connected to the vibration chamber. In a liquid seal vibration isolator provided with a vibration member for generating vibration having substantially the same phase as the vibration to be inputted to the vibration, and floating around the vibration member with an elastic seal,
A throttle wall is provided in a partition wall that divides the vibration chamber and the main liquid chamber, and an elastic film is provided to partition between the throttle path and the vibration member, and the throttle is provided between the elastic film and the partition wall. An active liquid seal vibration isolator comprising a small liquid chamber communicating with the main liquid chamber only through a passage, and the elastic film being made larger than an opening area of the throttle passage .   In the first aspect of the invention, the vibration member vibrates only the vibration to be vibrated at a specific frequency, and the vibration member is free to vibrate by elastic deformation of the elastic seal at other frequencies. An active liquid seal vibration isolator characterized by the above.   2. The active liquid seal vibration isolator according to claim 1, wherein the small liquid chamber and the vibration chamber are not in communication with each other with the elastic film interposed therebetween.   4. The active liquid seal vibration isolator according to claim 1, wherein the elastic film has a non-linear spring characteristic.   2. The active liquid seal vibration isolator according to claim 1, wherein the elastic film is attached by removing an initial strain generated during molding. In the first aspect, wherein the pores when releasing the liquid in the oscillating chamber on the partition wall from the oscillating chamber both the resonance frequency is set lower than the resonance frequency of the damping orifice passage communicating the main liquid chamber and the auxiliary liquid chamber An active liquid seal vibration isolator characterized by comprising:

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