JP3628197B2 - Switchable liquid-filled vibration isolator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid-filled vibration isolator used mainly for supporting a vibration generator such as an automobile engine.
[0002]
[Prior art]
As a liquid-filled vibration isolator such as an engine mount that supports the vibration of a vibration generating body such as an automobile engine so as not to be transmitted to the vehicle body side, when setting the damping effect of different frequencies to high, two set for each frequency There is known a switching type liquid-filled vibration isolator that opens and closes an orifice opening so that one of the orifices can be selectively used depending on the phenomenon.
[0003]
In addition, opening and closing of the orifice communication path (for example, the idle communication path) is performed by restraining / detaching the diaphragm or flexible membrane. As a technique for this, the diaphragm or flexible membrane restrained by the negative pressure is freed. Two methods have been proposed (see Japanese Patent Laid-Open No. 4-321832: hereinafter referred to as “conventional example 1”) and a method of detaching the diaphragm or flexible membrane covering the end of the orifice by a negative pressure (Japanese Patent Laid-Open No. Hei 4-318232). No. 4-254024 and JP-A-8-270718: hereinafter referred to as “conventional example 2”).
[0004]
[Problems to be solved by the invention]
However, the conventional example 1 requires a surge tank for using negative pressure at a speed other than the idle rotation speed at which negative pressure is difficult to take, and the conventional example 2 requires a large movable part to close the idle orifice. The current situation is that it relies on an unstable rubber-like elastic body.
[0005]
[Means for Solving the Problems]
In view of the current situation, the present inventors have conducted extensive research to provide a switchable liquid-filled vibration isolator having a low cost and excellent stability, and as a result, can switch between negative pressure and atmospheric pressure. When a spring for urging the second diaphragm is arranged in the air chamber on the side closing the second sub liquid chamber, and the damping is performed using only the first orifice, the atmospheric pressure and the urging force of the spring are When the second orifice is closed by using the second orifice, and when the second orifice is used for damping, the second orifice is made to communicate against the biasing force by using a negative pressure. In order to use the urging force of the spring, a large moving part is not required to close the second orifice (for example, idle orifice), and negative pressure is used for damping in a high frequency range such as an idle vibration frequency band. Can be used In surge tank or the like, were found to be able to provide an inexpensive vibration damping device does not affect the associated parts.
[0006]
That is, the present invention is provided with a partition that partitions a liquid chamber formed between the vibration isolating base and the first diaphragm into a main liquid chamber and a first sub liquid chamber, and the main liquid chamber is provided in the partition. And a first orifice communicating with the first sub-liquid chamber, a second orifice communicating with the main liquid chamber separately from the first orifice, and a second orifice disposed at the end of the second orifice A sub-liquid chamber, a second diaphragm constituting a part of the second sub-liquid chamber, and an air chamber disposed on the opposite side of the second sub-liquid chamber across the second diaphragm. Provided with a switching means that allows the air chamber to be switched between atmospheric pressure and negative pressure, and a spring for biasing the second diaphragm is disposed on the air chamber on the side closing the second sub liquid chamber, This spring reaction force is canceled by switching between negative pressure and atmospheric pressure, and the damping effect of different frequencies is selectively exerted. In which was to so that.
[0007]
The positions of the first and second orifices are not particularly limited as long as they are formed in the partition, and are appropriately selected in a form in which the orifice length corresponding to the vibration frequency range to be attenuated is obtained. Is possible. For example, a configuration in which the upper and lower tiers are provided on the periphery of the partition, or a configuration in which the first orifice is provided on the outer side in the radial direction of the partition and the second orifice is provided on the inner side.
[0008]
Further, the second sub liquid chamber and the air chamber at the end of the second orifice, and the second diaphragm are not limited in size and position. However, the air chamber and the second diaphragm are connected to the entire liquid chamber. If it is set to be smaller than the above, it is possible to provide an anti-vibration device that is excellent in responsiveness at the time of switching between atmospheric pressure and negative pressure and in the reliability of the diaphragm. For example, the aspect which sets these air chambers and the 2nd diaphragm small in the center part of a partition can be illustrated.
[0009]
In addition, the structure of the partition body may be a single molded product or a two-member structure composed of upper and lower partition members as long as it has two orifices, a second diaphragm, a second auxiliary liquid chamber, and an air chamber. In addition, it may be any of a three-member structure comprising an upper and lower partition member and an orifice member sandwiched between them, but a two-member or three-member structure may be used as a spring can be incorporated. Is preferred.
[0010]
As a three-member partition, an upper partition member and a lower partition member and an orifice member sandwiched between the upper and lower partition members are provided, and a space formed on the inner side of the orifice member is a second diaphragm. Thus, a configuration in which the second auxiliary liquid chamber and the air chamber are partitioned vertically can be exemplified. The space in this case is a configuration in which a bottomed concave portion with the upper surface of the orifice member opened is sealed with an upper partition member, or a through-hole penetrating the orifice member vertically is formed, and the upper and lower openings are divided into upper and lower partition members. Any of the configurations sealed with can be adopted. However, in view of sealing performance, a configuration having a bottomed recess is a more preferable mode.
[0011]
Examples of means for switching the air chamber between negative pressure and atmospheric pressure include a configuration in which a through hole is formed from the air chamber to the outside and a switching valve is provided at the end thereof.
[0012]
The vibration frequency range in which the first orifice and the second orifice are attenuated is not particularly limited, but the first orifice is in the shake vibration attenuation frequency range, and the second orifice is in the first frequency range. The aspect set to the idle vibration damping frequency range of a higher frequency range than an orifice can be illustrated.
[0013]
If the spring is damped using only the first orifice, the second orifice can be closed using atmospheric pressure and the biasing force of the spring, and if the spring is damped using the second orifice, Any device that can communicate the second orifice against the biasing force using negative pressure can be applied to both coil springs and leaf springs, but when the second orifice is used. In order not to constrain the central portion of the second diaphragm so that the second diaphragm bends suitably, it is preferable to employ a coil spring that contacts the outer peripheral portion of the second diaphragm. In this case, in order to prevent the second diaphragm from being damaged by the coil spring, a configuration in which a ring-shaped rubber film protective cover is interposed between the coil spring and the second diaphragm is preferable. Further, the spring constant of the spring is not particularly limited, but it is desirable to set the spring constant so as to be bent by a negative pressure.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a longitudinal sectional view of a liquid filled type vibration damping device showing an embodiment of the present invention, and FIG. 2 is a partially cutaway longitudinal sectional view of the same. The liquid-filled vibration isolator 1 according to the present embodiment includes an upper mounting bracket 2 that is attached to a vibration generator such as an engine, a lower mounting bracket 3 that is attached to a vehicle body, and both the mounting brackets 2 and 3. A vibration isolating base 4 made of a rubber-like elastic body to be connected, and a first mounting chamber 3 facing the anti-vibration base 4 on the lower mounting bracket 3 side and constituting the liquid chamber 5 with the anti-vibration base 4. An apparatus main body is constituted by the diaphragm 6, and a partition body 7 for partitioning the liquid chamber 5 into a main liquid chamber 5 a and a sub liquid chamber 5 b is provided in the main body. Two orifices 24, 35, a second auxiliary liquid chamber 43, an air chamber 44, and a second diaphragm 33, vibration damping functions in different frequency ranges by these two orifices, and vibration by the vibration-proof substrate 4 Insulation function is demonstrated
[0015]
The upper mounting bracket 2 is formed in a flat plate shape, and a mounting bolt 9 that protrudes upward and supports an engine or the like is fixed at the center thereof. Further, in order to absorb a large displacement, the base end portion of the stopper metal fitting 10 (stabilizer metal fitting) having a cross-section protruding in the lateral direction is positioned and fixed on the upper surface of the upper attachment fitting 2 by screws 11. Yes.
[0016]
The lower mounting bracket 3 includes a bottomed cylindrical portion 13 having an outer flange 13a that is widened at the upper end, and a cylindrical body portion 14 having a lower end portion fastened to the outer flange 13a from the outside.
[0017]
A mounting bolt 15 that is fixed to the vehicle body side is fixed to the bottom of the bottomed tubular portion 13. The cylindrical body 14 has a lower end flange 14a widened at the lower end thereof, and the lower side of the first diaphragm 6 and the partition 7 between the lower end flange 14a and the outer flange 13a of the bottomed cylindrical part 13. The outer peripheral part of the partition member 27 is clamped. And the fastening part 16 is extended at the front-end | tip of the lower end flange 14a. The fastening portion 16 has a U-shaped cross section by being caulked and fastened so that the outer flange 13a of the bottomed tubular portion 13 is inserted into the fastening portion 16 and surrounded from the outside.
[0018]
In addition, the cylindrical body portion 14 is expanded outwardly in a tapered shape, and a flange 17 is formed on a part of the upper end of the expanded portion 14b so as to face the tip of the stopper fitting 10. The anti-vibration base 4 is vulcanized and bonded so as to surround the inner surface of the expanded portion 14 b and the outer peripheral portion of the flange 17.
[0019]
The anti-vibration base 4 has a rubber-like elastic body formed in an umbrella shape and is vulcanized and bonded to the cylindrical body 14 of the upper mounting bracket 2 and the lower mounting bracket 3, and the flange 17 of the cylindrical body 14. Is extended to a position facing the inner surface of the front end of the stopper fitting 10, and this extended portion is a large displacement absorbing stopper portion 20. A reinforcing metal fitting 21 is embedded in the stopper portion 20 between the flange 17 and the stopper metal fitting 10. Further, the rubber-like elastic body of the vibration isolating base 4 extends in a thin film shape to the lower end of the inner wall of the cylindrical body portion 14, and the partition 7 is press-fitted into the inner peripheral wall of the thin film portion 22.
[0020]
The first diaphragm 6 has a flexible rubber-like elastic film, and the inner end of an annular support fitting 25 is embedded and integrated in the outer peripheral portion thereof, and this support fitting 25 is connected to the bottomed tubular portion 13. It is mounted on the outer flange 13a. The space surrounded by the first diaphragm 6, the lower surface portion of the vibration isolating base 4 and the thin film portion 22 is a liquid chamber 5 filled with an encapsulated liquid, and the partition body 7 divides the liquid chamber 5 vertically. Is arranged.
[0021]
As shown in FIGS. 1 and 2, the partition body 7 has a three-member configuration mainly including an upper partition member 26, a lower partition member 27, and an orifice member 28 interposed therebetween.
[0022]
The upper partition member 26 is composed of a disk-shaped metal member, and its peripheral edge is bent downward to form a flange 26a, and its peripheral corner portion is at the liquid chamber side outer peripheral end of the vibration isolating base 4. It is placed and pressed on a notch step 30 formed in an annular shape and having an L-shaped cross section. Further, the central portion of the upper partition member 26 is slightly recessed on the lower side corresponding to the second diaphragm 33. Further, an inlet / outlet 32 on the main liquid chamber side communicating with the two orifices 24 and 35 of the partition 7 is formed in a part of the outer periphery of the upper partition member 26.
[0023]
The lower partition member 27 is made of a disk-shaped metal member, its outer peripheral end is extended outward in the radial direction, and only the extended portion 29 is a bottomed cylindrical portion of the lower mounting bracket 3. 13 and the fastening portion 16 of the cylindrical body portion 14 are fixed by caulking. A central portion of the lower partition member 27 is protruded upward so as to clamp the orifice member 28 between the upper partition member 26 and ensure the sealing performance of the orifices 24 and 35 of the orifice member 28. . Further, a sub liquid chamber side inlet / outlet 27 a communicating with the first sub liquid chamber 5 b side is formed in a part of the outer periphery of the lower partition member 27.
[0024]
The orifice member 28 is an aluminum columnar molded product, and orifice grooves 23 and 31 having an L-shaped cross section are formed in the circumferential direction in two upper and lower sides with a partition wall 28a sandwiched between outer peripheral portions of the periphery thereof. . Further, a stepped recess 38 having an open upper surface is formed in the central portion on the inner side of the orifice grooves 23 and 31.
[0025]
Of the upper and lower two-stage orifice grooves 23, 31, a space portion surrounded by the lower first orifice groove 23, the inner peripheral wall of the thin film portion 22 of the vibration isolation base 4 and the lower partition member 27 is the first orifice 24. On the other hand, a space portion surrounded by the upper second orifice groove 31 and the inner peripheral wall of the thin film portion 22 and the upper partition member 26 is a second orifice 35.
[0026]
A part of the partition wall 28a of the upper and lower orifice grooves 23 and 31 is formed with a communication hole 37 that communicates with both the orifice grooves 23 and 31, and the first orifice 24 includes the communication hole 37 and the second orifice. A portion 35 is communicated with the main liquid chamber 5a side, and is communicated with the first sub liquid chamber 5b through the sub liquid chamber side entrance 27a.
[0027]
Further, a communication hole 39 is formed in a part of the peripheral wall of the second orifice groove 31 and communicates with the upper side of the stepped recess 38 in the central portion. The concave portion 38 is formed with a large diameter on the upper side and a small diameter on the lower side, a stepped portion 40 is formed in the middle portion, the upper surface is sealed by the upper partition member 26, and the inner space is vertically moved by the second diaphragm 33. A second sub-liquid chamber 43 and an air chamber 44 are formed by being partitioned by each other. An outer peripheral collar fitting 42 having an L-shaped cross section of the second diaphragm 33 is press-fitted into the stepped portion 40, the second sub liquid chamber 43 is formed above the second diaphragm 33, and the second air chamber 44 is disposed below the second diaphragm 33. Has been.
[0028]
As shown in FIG. 2, the air chamber 44 is formed with a through hole 45 extending outward from the apparatus body. The through hole 45 is opened to the outside by a larger-diameter opening 46 formed in the apparatus body. Yes. A pipe 48 communicating from the outside of the opening 46 to the switching valve 47 is press-fitted into the through hole 45, and is switched between negative pressure and atmospheric pressure by switching operation of the switching valve 47 connected to the negative pressure source 49. The movement of the second diaphragm 33 is controlled by changing.
[0029]
The air chamber 44 includes a coil spring 50 that urges the second diaphragm 33 upward (in the direction of closing the second auxiliary liquid chamber 43) between the bottom of the air chamber 44 and the outer periphery of the second diaphragm 33. Is intervening. The upper end of the coil spring 50 is covered with a rubber cover 51 made of synthetic resin, and is in contact with the second diaphragm 33 via the cover 51, and the lower end is formed at the bottom of the air chamber 44. It is fitted on the misalignment prevention convex portion 53. The protective cover 51 is formed in a ring shape having an opening that allows the second diaphragm 33 to bend. The coil spring 50 is set to a spring constant that can be bent by a negative pressure.
[0030]
In the above configuration, when the volume of the second air chamber 44 is reduced by the negative pressure from the negative pressure source, the second diaphragm 33 is separated from the upper partition member 26 against the biasing force of the coil spring 50, and the second The diaphragm 33 is set to a free state. As a result, the filled liquid communicates also with the second orifice 35 to be in a double orifice state, and the damping performance is exhibited at a predetermined frequency.
[0031]
When the air chamber 44 is switched to the atmospheric pressure, the second diaphragm 33 is pressed against the upper partition member 26 by the urging force of the spring 50, preventing communication of the sealed liquid to the second orifice 35, and the first orifice Limited to 24 connections.
[0032]
At this time, since the second air chamber 44 and the second diaphragm 33 are smaller than the entire liquid chamber, the responsiveness at the time of switching is improved, and a vibration isolator excellent in the reliability of the diaphragm 33 can be provided. Further, since the second orifice 35 can use a negative pressure in the idle rotation region, it is possible to provide an inexpensive vibration isolator that does not affect the accompanying components such as a surge tank.
[0033]
【The invention's effect】
As is apparent from the above description, according to the present invention, when a diaphragm restraining spring is arranged in the second air chamber and the second orifice is communicated, the pressure is switched to negative pressure and the damping effect is selected for a predetermined frequency. Therefore, it is possible to provide an anti-vibration device that is inexpensive and excellent in stability.
[Brief description of the drawings]
FIG. 1 is a front sectional view of a liquid-filled vibration isolator showing a first embodiment of the present invention. FIG. 2 is a side sectional view of the vibration isolator.
DESCRIPTION OF SYMBOLS 1 Liquid enclosure type vibration isolator 2 Upper mounting bracket 3 Lower mounting bracket 4 Anti-vibration base 5 Liquid chamber 5a Main liquid chamber 5b First sub liquid chamber 6 First diaphragm 7 Partition 23 First orifice groove 24 First 1 orifice 26 upper partition member 27 lower partition member 28 orifice member 31 second orifice groove 33 second diaphragm 35 second orifice 38 recess 40 stepped portion 43 second sub liquid chamber 44 air chamber 47 switching valve 50 Spring 51 Resin cover 53 Projection

Claims (3)

A partition for partitioning a liquid chamber formed between the vibration isolating base and the first diaphragm into a main liquid chamber and a first sub liquid chamber;
The partition includes an upper partition member and a lower partition member, and an orifice member sandwiched between the upper and lower partition members,
A first orifice that communicates with the main liquid chamber and the first sub liquid chamber and a second orifice that communicates with the main liquid chamber separately from the first orifice are arranged vertically at the peripheral edge of the partition. Arranged in two stages,
A space portion surrounded by a concave portion whose upper surface is opened and the upper partition member is formed in the central portion on the inner side of the orifice member, and the space portion is separated from the second sub liquid chamber by a second diaphragm. It is divided into an air chamber up and down,
The second orifice and the second auxiliary liquid chamber communicate with each other through a communication hole formed in a part of the peripheral wall of the orifice member,
A switching means for switching the air chamber between atmospheric pressure and negative pressure is provided, and a coil spring for biasing the second diaphragm is disposed in the air chamber on the side closing the second sub-liquid chamber. And
A switching type liquid-filled type vibration damping device, wherein the reaction force of the spring is canceled by switching between the negative pressure and the atmospheric pressure so as to exhibit an attenuation effect of different frequencies. 2. The switching type liquid-filled vibration isolator according to claim 1, wherein an upper end of the coil spring is brought into contact with an outer peripheral portion of the second diaphragm via a ring-shaped rubber film protective cover. The switchable liquid-filled vibration isolator according to claim 1 or 2, wherein the second orifice is set so as to attenuate vibrations in a higher frequency range than the first orifice.

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