JP3978539B2 - Liquid-filled vibration isolator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid-filled vibration isolator.
[0002]
[Prior art]
As shown in FIG. 8, the liquid-filled vibration isolator is composed of a rubber-like elastic material in which a first attachment 1 attached to a vibration body such as an automobile engine and a cylindrical second attachment 2 attached to a vehicle body frame. A diaphragm 5 is formed on the second fixture 2 so as to form a liquid chamber 4 between the anti-vibration base 3 and the anti-vibration base 3. The liquid chamber 4 is connected to the first liquid chamber 6 and the second liquid. A thin partition plate 20 is provided as a partition portion 8 that partitions the chamber portion 7, and an orifice 22 that connects the first liquid chamber portion 6 and the second liquid chamber portion 7 is formed. With this structure, it is possible to obtain the liquid flow effect of both the liquid chamber portions 6 and 7 and the vibration isolation effect of the vibration isolation base 3 to suppress the transmission of vibration from the vibrating body to the vehicle body.
[0003]
In addition to these structures, a stopper portion 10 that projects outward in the radial direction of the second fixture 2 is formed on the second fixture 2, and the stopper portion 10 is formed in the axial direction of the second fixture 2. The plate-like stopper member 11 received in step 1 is cantilevered on the first fixture 1 side to prevent excessive compression / extension (large displacement) of the vibration-proof base 3.
[0004]
By the way, when the natural frequency of each part of the liquid filled type vibration isolator is within the range of the vibration frequency of the vibrating body during normal operation, each part resonates during normal operation, and As a result, the spring constant increases and the vibration isolation effect cannot be obtained sufficiently.
Therefore, conventionally, the stopper member 11, the partition plate 8, and the vibration isolation base 3 have been formed so that their natural frequencies are higher than the range of the frequencies.
[0005]
[Problems to be solved by the invention]
According to the above-described conventional configuration, resonance of the stopper member, the partition plate, and the vibration isolating base can be avoided during normal operation, and an increase in the spring constant of the liquid-filled vibration isolator can be avoided, thereby sufficiently obtaining a vibration isolating effect. However, since all of the stopper member 11, the partition plate 8, and the vibration isolating base 3 are formed so that their natural frequencies are high, the vibration frequency of the vibrating body exceeds the above range. In the operating state, all of the stopper member, the partition plate, and the vibration isolating base resonate all at once, and the spring constant of the liquid-filled vibration isolator suddenly increases as shown by the one-dot chain line in FIG. The vibration performance was likely to be greatly reduced (FIG. 4 is described in detail in the section [Embodiment]).
[0006]
An object of the present invention is to provide a liquid-filled vibration isolator that does not easily deteriorate the vibration isolating performance even when the operating state is such that the vibration frequency of the vibrating body exceeds the range during normal operation.
[0007]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a first mounting tool that is attached to the vibrating body side and a cylindrical second mounting tool that is attached to the vehicle body side, and the first mounting tool and the second mounting tool are made of rubber. The second fixture is provided with a diaphragm for forming a liquid chamber between the first anti-vibration base and the first liquid chamber portion and the second anti-vibration base. A liquid-filled vibration isolator having a partition portion for partitioning into a liquid chamber portion and forming an orifice for communicating the first liquid chamber portion and the second liquid chamber portion, and radially outward of the second fixture to form a target stopper portion to the second fixture side overhanging side, provided the stopper member which receives in the axial direction of the target stopper portion said second fixture to said first fixture side, the stopper The member has an overlapping portion that overlaps the first fixture, and the vibration is The superposition part is sandwiched between the first attachment and the attachment on the vibrating body and cantilevered on the first attachment in a state in which the first attachment is attached to the attachment on the body. The stopper member is provided with a dynamic damper, and the damper is supported and connected to a support bracket erected on the overlapping portion so that the damper body protrudes laterally outward from the overlapping portion. It is configured to be supported in a cantilever state, and the vibration of the stopper member is absorbed by the dynamic damper to avoid resonance of the stopper member .
[0009]
Claims configuration of the invention according to claim 2, in the configuration of the invention according to claim 1, wherein the dynamic damper, through the mounting bolts the damper body and configured to support connected to said support bracket, said damper body, said attachment The inner cylinder through which the bolt is inserted and the outer cylinder surrounding the inner cylinder are connected by a rubber-like elastic body interposed between them.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0012]
[First Embodiment]
1, 2 and 3 show a liquid-filled vibration isolator for an automobile. This liquid-filled vibration isolator includes a plate-shaped first mounting bracket 1 that is mounted on an engine (corresponding to an object to be mounted) and an upper end portion of a cylindrical second mounting bracket 2 that is mounted on a vehicle body frame below the engine. A diaphragm 5 is provided on the second fixture 2 to form a liquid chamber 4 between the vibration isolator base 3 made of a rubber-like elastic material. A partition portion 8 is provided to partition the liquid chamber portion 6 and the lower second liquid chamber portion 7, and the liquid chamber portions 6 and 7 are filled with liquid.
[0013]
A stoppered portion 10 that projects outward in the radial direction of the second mounting bracket 2 is formed on the upper end side of the second mounting bracket 2, and the stoppered portion is mounted in a state where the first mounting bracket 1 is attached to the engine. A plate-like stopper fitting 11 (corresponding to a stopper member) that receives 10 in the axial direction (vertical direction) and the lateral direction of the second attachment fitting 2 is the first attachment fitting 1 side. A separate body is provided to prevent excessive compression / elongation (large displacement) of the vibration-proof substrate 3. A dynamic damper 16 is provided on the stopper fitting 11. The structure and operation of the dynamic damper 16 will be described in detail later.
[0014]
The first mounting bracket 1 is mounted on the engine by screwing an upward mounting bolt 12 projecting from the center of the first mounting bracket 1 into an internal thread portion on the engine side. Reference numeral 19 denotes an upward positioning pin protruding from the first mounting bracket 1. The positioning pin 19 can accurately determine the position of the first fixture 1 relative to the engine side.
[0015]
The second mounting bracket 2 includes a cylindrical metal part 13 to which the vibration-proof base 3 is vulcanized and bonded, and a bottom metal part 14 that is caulked and fixed to the cylindrical metal part 13. A downward mounting bolt 15 projecting from the body is screwed into a female screw portion on the vehicle body frame side and attached to the vehicle body frame.
[0016]
The anti-vibration base 3 is formed in the shape of a truncated cone, and its upper end surface is vulcanized and bonded to the first mounting bracket 1, and its lower end outer peripheral portion is vulcanized and bonded to the upper end of the cylindrical bracket portion 13. ing. The rubber film portion 16 connected to the lower end portion of the vibration isolating base 3 is vulcanized and bonded to the inner peripheral surface of the cylindrical metal portion 13.
[0017]
As shown in FIG. 2, the diaphragm 5 includes a partially spherical rubber film body 17 and a ring fitting 18 on the outer peripheral side thereof.
[0018]
The partition part 8 includes a cylindrical part 9 fitted into the cylindrical metal part 13, a partition plate 20 between the inner peripheral walls slightly below the upper end of the cylindrical part 9, and a lower mounting flange 21. It is formed by pressing a thin metal plate. Among these, the cylindrical part 9 has both upper and lower ends projecting radially outward, and the upper end part and the lower end part on the base side of the mounting flange 21 are the rubber film part of the cylindrical metal part 13. 16 is fitted internally. Between the peripheral wall of the cylindrical part 9 and the rubber film part 16 of the cylindrical metal part 13, an orifice 22 is formed for communicating the first liquid chamber part 6 and the second liquid chamber part 7. The mounting flange 21 is caulked and fixed to the cylindrical fitting 13 together with the ring fitting 18 of the diaphragm 5 and the bottom fitting 14 of the second fitting 2.
[0019]
With the above structure, when a large amplitude vibration having a low frequency is generated, the liquid is attenuated by flowing between the liquid chambers 6 and 7 through the orifice 22, and a small amplitude vibration having a high frequency. When this occurs, the vibration is attenuated by the reciprocating deformation of the partition plate 20 without the liquid passing through the orifice 22.
[0020]
The stopper portion 10 includes a vibration-proof base portion in which a protruding piece 23 having a rectangular shape in a plan view on the upper end side of the cylindrical fitting 13 and a reinforcing fitting plate 24 below the protruding piece 23 are extended correspondingly. 25.
[0021]
The stopper fitting 11 is formed by integrally connecting a superposition portion 26 that overlaps the first attachment fitting 1 from above and a stopper action portion 27 that surrounds the stopper portion 10 from both the upper and lower directions and the lateral outer side. It is formed in a letter shape. Further, both ends of the overlapping portion 26 in the width direction are bent downward to form reinforcing ribs 28, and a bolt insertion hole 29 through which the mounting bolt 12 is inserted and a pin through which the positioning pin 19 is inserted into the overlapping portion 26. An insertion hole 30 is formed. The stopper acting portion 27 is also formed with a reinforcing rib 45 by raising its central portion in the width direction. Thereby, the intensity | strength of the stopper metal fitting 11 can be raised. In the stopper fitting 11 having the above structure, the overlapping portion 26 is sandwiched between the first attachment fitting 1 and the engine-side attachment portion and is cantilevered on the first attachment 1 side.
[0022]
The dynamic damper 16 will be described. A support bracket 31 is erected on one end side in the width direction of the overlapping portion 26 of the stopper fitting 11, and a damper main body 32 is detachably supported and connected thereto via a mounting bolt 33. .
[0023]
The damper main body 32 is configured by connecting an inner cylinder 34 through which the mounting bolt 33 is inserted and an outer cylinder 35 surrounding the inner cylinder 34 with a rubber-like elastic body 36 interposed therebetween. The support bracket 31 is formed in a “U” shape, and a nut 38 is fixed to the back surface of the vertical wall 37 between both side walls thereof, and a bolt insertion hole 39 for the nut 38 is formed in the vertical wall 37. In the plan view, the lower wall of the support bracket 31 is placed at the lower end of the stopper bracket 11 so that the vertical wall 37 is along the longitudinal direction of the stopper bracket 11, in other words, the axial center of the nut 38 is along the width direction of the stopper bracket 11. It adheres to the superposition part 26.
[0024]
The mounting bolt 33 is inserted into the inner cylinder 34 of the damper main body 32, and the mounting bolt 33 is screwed and connected to the nut 38. That is, the damper main body 32 is cantilevered by the support bracket 31 so as to project from the overlapping portion 26 to the laterally outward side.
[0025]
The mass and spring constant of the dynamic damper 16 are set corresponding to a high frequency of 900 Hz (tuned to a suppression target of 900 Hz), and the vibration at this frequency is applied to the liquid-filled vibration isolator. When added, the dynamic damper 16 is configured to particularly absorb the vibration of the stopper fitting 11.
[0026]
As shown in FIG. 4, the present inventor has experimentally determined the relationship between the frequency applied to the liquid-filled vibration isolator (Example 1) having the above structure and the spring constant of the liquid-filled vibration-proof device. Similarly, the relationship between the vibration frequency applied to the conventional liquid-filled vibration isolator without a dynamic damper provided on the stopper metal fitting and the spring constant of the liquid-filled vibration isolator was determined by experiment, and the results of both experiments were compared.
[0027]
[Experimental conditions]
Vibrations of 50 Hz to 1000 Hz and + −9.8 m / s ² were applied to the liquid-filled vibration isolator, and the spring constant of the liquid-filled vibration isolator for each frequency was measured.
[0028]
[results of the experiment]
In the conventional example, when a vibration of 50 Hz to 700 Hz is applied, the spring constant becomes a substantially constant value within 1500 N / mm. However, when a vibration exceeding 700 Hz is applied, the spring constant starts to increase greatly and a vibration of 900 Hz is applied. The maximum was 9000 N / mm.
[0029]
On the other hand, in Example 1, when the vibration of 50 Hz to 700 Hz is applied, the spring constant becomes a substantially constant value within 1500 N / mm, and when the vibration exceeding 700 Hz is applied, the spring constant starts to increase, and the vibration of 800 Hz is generated. When added, the maximum was 6500 N / mm. And when the vibration exceeding 800 Hz was added, the spring constant began to fall and became 4000 N / mm at 900 Hz. After that, it rose again to 6500 N / mm at 950 Hz, and the spring constant dropped again when vibration exceeding 950 Hz was applied. Thus, in Example 1, the maximum value of the spring constant of the liquid filled type vibration isolator was lower than that of the conventional example.
[0030]
[Second embodiment (reference example not included in the present invention; the same applies hereinafter) ]
As shown in FIGS. 5, 6, and 7, a mass damper 40 is provided in place of the dynamic damper 16 in the stopper fitting 11 of the liquid filled type vibration isolator. Other structures are almost the same as those of the liquid-filled vibration isolator of the first embodiment, and the description of the structure is omitted.
[0031]
The mass damper 40 is formed by polymerizing and welding and fixing a plurality of metal plates 41 having the same shape. Each metal plate 41 is formed by punching a plate material in a shape close to a trapezoid. Specifically, one hypotenuse is made shorter than the other hypotenuse and the base and top are made non-parallel. A portion corresponding to the short oblique side and upper side of the mass damper 40 obtained by superimposing these is welded and fixed to a concave portion of the inclined surface of the stopper fitting 11 formed in accordance with this portion.
[0032]
As shown in FIG. 4, the present inventor has determined the frequency and liquid-filled vibration isolation device applied to the liquid-filled vibration-proof device having the above structure (Example 2 (reference example not included in the present invention; the same applies hereinafter) ) . The relationship with the spring constant of the device was obtained by experiments. Further, the relationship between the frequency applied to the liquid filled type vibration isolator of the conventional example in which the mass damper 40 is not provided on the stopper metal fitting 11 and the spring constant of the liquid filled type vibration isolator was obtained by experiments, and the results of both experiments were compared. The experimental conditions and the results of the conventional experiment are as described in the first embodiment.
[0033]
In Example 2, when a vibration of 50 Hz to 600 Hz is applied, the spring constant becomes a substantially constant value within 1800 N / mm. When a vibration exceeding 600 Hz is applied, the spring constant starts to increase greatly, and when a vibration of 800 Hz is applied. The maximum was 9000 N / mm. As described above, in Example 2, the frequency at which the spring constant reached the maximum value was 100 Hz lower than that in the conventional example (maximum of 9000 N / mm at 900 Hz vibration).
[Another embodiment]
The stopper bracket may be integrally fixed to the first mounting bracket 1. The numerical values given in the above embodiment are merely examples, and may be different numerical values. The form of the dynamic damper or the mass damper is not limited to the above form.
[0034]
【The invention's effect】
According to the configuration of the first aspect in which the stopper member is provided with the dynamic damper, when the vibration state of the vibration body exceeds the vibration body frequency during normal operation, the vibration of the stopper member is dynamically changed. Can be absorbed with a damper .
[0035]
As a result, even if the partition plate and the vibration isolating base resonate in the above operating state, the stopper member can be prevented from resonating, and all of the partition plate, the vibration isolating base, and the stopper resonate. Compared to the conventional structure, it is possible to suppress an increase in the spring constant of the liquid-filled vibration isolator in the above operating state. Further, in a normal operation state where the vibration frequency of the vibrating body is within a predetermined range, it is possible to avoid resonance between the stopper member and the partition plate as in the conventional structure.
[0036]
Accordingly, it is possible to provide a liquid-filled type vibration isolator in which the vibration isolating performance is unlikely to deteriorate even when the operating state is such that the frequency of the vibrating body exceeds the frequency range of the vibrating body during normal operation. .
[0037]
Moreover, according to the structure of this invention , the vibration of the stopper member which is cantilever-supported by the 1st fixture side and is easy to vibrate can be absorbed with a dynamic damper .
[0038]
According to the configuration of the second aspect , the dynamic damper is configured by supporting and connecting the damper main body to the support bracket via the mounting bolt, and the damper main body includes the inner cylinder through which the mounting bolt is inserted and the outer cylinder surrounding the inner cylinder. Since the cylinder is connected by a rubber-like elastic body interposed between them, the structure of the dynamic damper can be simplified. Furthermore, since the damper main body is detachable from the support bracket, the damper main body can be appropriately changed to another damper, and the damper main body that matches the stopper member can be attached to the support bracket. Can be set more accurately.
[Brief description of the drawings]
[Fig. 1] Plan view of liquid-filled vibration isolator [Fig. 2] Vertical front view of liquid-filled vibration isolator [Fig. 3] Side view of liquid-filled vibration isolator [Fig. 4] Liquid-filled vibration isolator FIG. 5 is a plan view of the liquid-filled vibration isolator of the second embodiment. FIG. 6 is a longitudinal front view of the liquid-filled vibration isolator of the second embodiment. 7] Side view of the liquid filled type vibration isolator according to the second embodiment [FIG. 8] A longitudinal front view showing the prior art [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 1st fixture 2 2nd fixture 3 Anti-vibration base | substrate 4 Liquid chamber 5 Diaphragm 6 1st liquid chamber part 7 2nd liquid chamber part 8 Partition part 10 Stopper part 11 Stopper member 16 Dynamic damper 22 Orifice 23 Overhang piece 24 Reinforcing bracket 25 Anti-vibration base portion 31 Support bracket 32 Damper body 33 Mounting bolt 34 Inner cylinder 35 Outer cylinder 36 Rubber elastic body 40 Mass damper 41 Metal plate

Claims (2)

A vibration- proof base made of a rubber-like elastic material is provided , which includes a first attachment attached to the vibrating body side and a cylindrical second attachment attached to the vehicle body side. And a diaphragm for forming a liquid chamber between the second anti-vibration base and a partition for partitioning the liquid chamber into a first liquid chamber and a second liquid chamber. A liquid-filled vibration isolator having an orifice for communicating the first liquid chamber portion and the second liquid chamber portion ,
A stopper member projecting outwardly in the radial direction of the second fixture is formed on the second fixture side, and a stopper member for receiving the stopper portion in the axial direction of the second fixture is Provided on the first fixture side,
The stopper member includes an overlapping portion that overlaps with the first attachment, and the overlapping portion is attached to the first attachment and the vibration body in the attachment state of the first attachment to the attachment on the vibration body. Configured to be sandwiched between the mounting portion and cantilevered to the first fixture side,
The stopper member is provided with a dynamic damper, and the dynamic damper is connected to a support bracket erected on the overlapping portion so that the damper body protrudes laterally outward from the overlapping portion. A liquid-filled vibration isolator configured to be cantilevered and absorbing vibrations of the stopper member by the dynamic damper to avoid resonance of the stopper member . The dynamic damper, through the mounting bolts the damper body and configured to support connected to said support bracket, said damper body, an inner cylinder for inserting the mounting bolt, and an outer tube surrounding the inner tube thereof The liquid-filled vibration isolator according to claim 1 , wherein the liquid-filled vibration isolator is connected by a rubber-like elastic body interposed between the two.

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