JPS60249749A - Vibro-isolator - Google Patents

Abstract

PURPOSE:To dampen vibration of high frequency in a vibro-isolator by dividing a hollow chamber made of elastic material into two small fluid chambers by a partition wall, forming a through-hole, that is, a restricting passage through one of said chamber, and forming a secondary restricting passage between the external periphery of a vibration plate and a fixed peripheral wall. CONSTITUTION:The base plate 10 of a vibro-isolator is attached to a car body 14, and a liquid chamber 30A is formed between a partition wall 32 and a diaphragm 28. A middle liquid chamber 30B and a lower fluid chamber 30C are communicated with each other by a restricting passage 38 which is formed between the external periphery of a vibration plate 36 and the internal periphery of the base plate 10. A cylindrical body 40 passes through the partition wall 32 and has a restricting passage 42 inside. The vibro-isolator therefore enables damping of vibration through a wide frequency range.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a vibration isolator for reducing vibrations from a vibration source.

[Background Art] A vibration isolating device, generally called a vibration isolating rubber, is used, for example, in an automobile engine mount to absorb vibrations from an engine in an automobile and prevent them from being transmitted to the vehicle body.

This vibration isolator has a structure in which a hollow chamber that can be expanded and contracted by an elastic material is used as a liquid chamber, this liquid chamber is divided into small liquid chambers by a partition wall, and an orifice is provided in this partition wall to communicate the small liquid chambers. is used.

In this vibration isolator, it is possible to generate a desired loss at a predetermined frequency by adjusting the size of the orifice, etc.

However, in this vibration isolator, if a high frequency exceeding the frequency at which loss occurs is applied, the fluid in the orifice will become clogged, resulting in an increase in the dynamic spring constant and a decrease in the ride comfort of the automobile.

For this reason, a structure has conventionally been proposed in which a movable plate capable of minute vibrations is provided near a partition wall that partitions a small liquid chamber to suppress internal pressure changes. However, even in this case, it is impossible to significantly reduce the dynamic magnification.

[Object of the Invention] Taking the above-mentioned facts into account, the present invention aims to provide a vibration isolating device that can appropriately attenuate even high-frequency vibrations and obtain a large loss factor.

[Summary of the Invention] In the vibration isolator according to the present invention, a hollow chamber is divided into three or more small fluid chambers by a plurality of partition walls, and one of the plurality of partition walls is provided with a through hole to form a first restriction passage. A second restriction passage is formed between the outer periphery of the vibrating plate and the fixed peripheral wall in the other one of the plurality of partition walls, thereby causing a large loss factor to the first restriction passage during large-amplitude, low-frequency vibration. In the case of small-amplitude high-frequency vibrations, a low dynamic magnification is obtained in the second restriction passage.

[Embodiments of the Invention] FIG. 1 shows a sectional view of a vibration isolator to which the present invention is applied. This vibration isolator is configured to be used in automobiles as an engine mount.

The base plate lO of this vibration isolator has a port 1 in the center.
2 hangs down and is attached to the vehicle body 14. In addition, the periphery of the base play) 10 is cylindrical,
The upper end portion is a seven-rung portion 16 that protrudes in the radial direction.

The bottom surface of a cylindrical rubber 18 is vulcanized and bonded to the flange portion 16, and this rubber 18 serves as a vibration absorber. It is also possible to use other elastic bodies in place of this rubber 18. A flange portion 22 of a top plate 20 is vulcanized and bonded to the top surface of the rubber 18. This top plate 20 has a substantially symmetrical shape with the base plate 10.

A bolt 24 is provided upright on the central raised portion to mount and fix an automobile engine 26.

A diaphragm 28 is located inside the protrusion of the top play 120.
The peripheral edge is vulcanized and bonded. This diaphragm 28
, top plate 20. Rubber 18, base plate 10
The inside forms a liquid chamber 30, which is filled with water. Further, an air chamber 31 is formed between the diaphragm 28 and the central raised portion of the top plate 20.

A partition wall 32 projects from the top plate 20 in the axial direction toward the inside of the flange portion 22 . This partition wall 32 forms an upper liquid layer 30A between it and the diaphragm 28.

An arm 34 protrudes from a part of the partition wall 32, and a vibrating plate 36 is fixed to the tip. This vibrating plate 36 has a disk shape, and a middle liquid chamber 30B is located between the upper part of this vibrating plate 36 and the partition wall 32, and a lower liquid chamber 30B is located between the lower part of the vibrating plate 36 and the base plate 10.
C, therefore, the middle liquid chamber 30B and the lower liquid chamber 30
C is communicated with via a restriction passage 38 formed between the outer periphery of the vibrating plate 36 and the inner periphery of the base plate IO. As a result, the restricted passage 38 forms a ring-shaped orifice, and the surface facing the orifice has a large area.

On the other hand, a cylindrical body 40 penetrates through the battlement wall 32, and the inside thereof forms a restriction passage 42. This restriction passage 42 communicates with the upper liquid chamber 30A and the middle liquid chamber 30B, and has a smaller cross-sectional area than the restriction passage 38, and a smaller surface area facing the restriction passage 42.

Furthermore, a movable plate 44 is attached to the central part of the partition wall 32, and is movable by a certain amount with respect to the partition wall 32. This movable plate 44 is attached to the partition wall 32 by a U-shaped portion 44A formed around the partition wall 32 holding the inner circumference of a circular hole 46 formed in the partition wall 32.
The opening width of the character-shaped portion 44A is slightly larger than the wall thickness of the partition wall 32, thereby allowing the movable plate 44 to move up and down by a minute amount.

Next, the operation of this embodiment will be explained.

The base plate 10 is fixed to the vehicle body 14 via ports 12, and an engine 26 is placed on the top plate 20 and fixed with bolts 24.

When the engine 26 is installed, the weight of the engine 26 acts on the top plate 20, so the rubber 18 is compressed and the pressure in the liquid chamber 30 increases. This pressure increase causes the diaphragm 28 to be displaced in the direction in which the air chamber 31 is contracted.

When the engine is running, vibrations generated in the engine are transmitted through the top plate 20. The rubber 18 can absorb vibrations based on internal friction (vibration damping function).

When the frequency of vibration is low, the amplitude is large and a damping effect occurs based on the viscous resistance caused by the passage of liquid in the restricted passage 42 having a small cross-sectional area, thereby improving the vibration isolation effect. In this case, since the restricted passage 38 has a large cross-sectional area,
There is almost no damping effect in this part.

Further, when the vibration of the engine 26 is high frequency, the amplitude is small and the restriction passage 42 may become clogged. However, the vibration plate 36, which is directly transmitted to the partition wall 32 via the arm 34, vibrates following the vibration of the partition wall 32 during this high frequency vibration. As a result, the liquid near the restriction passage 38 having a large cross-sectional area causes liquid column resonance,
This generates a large low dynamic magnification and absorbs high frequency vibrations.

The pressure in the liquid chamber 30 is prevented from increasing due to the vibration of the movable plate 44 during high frequency vibration.

Therefore, as shown in Figure 2, even when the frequency is high, the dynamic spring constant is low, and a large loss factor can be achieved.
It becomes possible to maintain the dynamic magnification at 1 or less.

Next, FIG. 3 shows a vibration isolating device according to a second embodiment of the present invention.

In this embodiment, a base block 48 that is attached to the vehicle body 14 is provided in place of the base plate IO of the previous embodiment. The outer periphery of the base block 48 and the top plate 2JO-
A ring-shaped rubber 18 is vulcanized and bonded between the flange portion 22 and the flange portion 22 . Further, the vibration plate 36 is fixed to the upper end of a support column 50 erected from the base block 48, and a restriction passage 38 is formed between the vibration plate 36 and the inner circumference of the top plate 20.
is formed.

Further, in this embodiment, a diaphragm 52 is disposed corresponding to the upper end of the rubber 18, and an air chamber 54 is formed at the upper end of the comb 18. This air chamber 54 is provided as desired, and may be omitted in some cases.

Further, in this embodiment, a movable plate is not used for the partition wall 32.

Also in the second embodiment of the present invention configured in this way,
The restriction passage 42 has the role of absorbing vibrations during low frequency vibrations, and the restriction passage 38 has the role of absorbing vibrations during high frequency vibrations. Therefore, as shown in FIG. 4, a large loss factor can be obtained over a wide range of frequencies.

Next, FIG. 5 shows a third embodiment of the present invention. In this embodiment, the vibrating plate 3 shown in the first embodiment is
A ring-shaped stopper rubber 56 is attached to the outer periphery of 6. Therefore, it has the role of regulating excessive displacement of the vibrating plate 36 in the radial direction, and any desired elastic body can be used.

Next, FIG. 6 shows a fourth embodiment of the present invention. This embodiment is a modification of the attachment of the rubber 18 of the first embodiment.

That is, in the base plate IO of this embodiment, a large-diameter flange portion 58 is provided upright at the outer peripheral end of the flange portion 16, and faces the outer peripheral portion of the top plate 20. Rubber 18 is attached between the inner circumference of this flange portion 58 and the outer circumference of top plate 20. Therefore, the rubber 18 of this embodiment is subjected to a greater shearing force than that of the first embodiment, and has a greater resistance force in the radial direction.

Next, FIG. 7 shows a vibration isolating device according to a fifth embodiment of the present invention. In this embodiment, the rubber 18 is
6 and the outer periphery of the top plate 20 in an inclined state. Therefore, the rubber 18 in this embodiment is capable of appropriately absorbing both shear forces and radial displacement forces. In addition, the restricted passage 42 of this embodiment
is attached to the movable plate 44.

The movable plate 44 in the above embodiment is provided as desired and may be omitted. In this case, the restriction passage 42 may be attached to the partition wall 32.

Next, FIG. 8 shows a vibration isolator according to a sixth embodiment of the present invention. In this embodiment, a middle liquid chamber 30B and a lower liquid chamber 30C are partitioned by a partition wall 32 extending inside the base plate 10, and communicated with each other by a restriction passage 42. Further, a vibration plate 36 forming a restriction passage 38 corresponding to the inner periphery of the base plate IO is fixed to the top block 62. Rubber 18 is obliquely vulcanized and bonded between the outer periphery of this top block 62 and the flange portion 16.

In this embodiment, a rubber 64 having a high loss factor is vulcanized and bonded to the upper part of the top block 62. A top plate 66 is fixed to the upper end of this rubber 64 for mounting an engine. Therefore, in this embodiment, the rubber 64 has the role of reducing the dynamic spring constant when high frequencies are generated.

A seventh embodiment of the present invention is shown in FIG. 9, which is a modification of the vibrating plate 36. In FIG. In this embodiment, the front and back sides of the central portion of the vibrating plate 36 are sandwiched between the parallel plate-shaped portion 34A of the arm 34, and the shaft portion of the arm 34 passes through the central circular hole 36A of the vibrating plate 36. The outer periphery of the shaft portion is spaced apart from the inner periphery of the circular hole 36A.

Therefore, the vibrating plate 36 is attached to the arm 34 so as to be relatively movable only in the horizontal direction. As a result, even when an excessive unbalanced load is applied, the vibrating plate 36 comes into contact with the upright portion of the base plate 10, and the arm 3 as shown in FIG.
4 and absorbs this, but the restricted passage 38
It is possible to ensure the same properties as those without unbalanced loads.

The vibrating plate 36 and movable plate 44 in each of the above embodiments can be made of metal, synthetic resin, etc., and preferably have a hardness of Shore D of 50 or more.

[Effects of the Invention] As explained above, in the vibration isolating device according to the present invention, vibration is suppressed by the first restriction passage formed by the through hole provided in the partition wall and the second restriction passage provided between the outer periphery of the vibration plate and the fixed peripheral wall. Since it absorbs vibrations, it is possible to absorb vibrations over a wide range of frequencies.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the first embodiment of the vibration isolator according to the present invention, FIG. 2 is a diagram showing the relationship between the dynamic spring constant and the frequency and tan δ of the first embodiment, and FIG. 4 is a cross-sectional view showing the second embodiment of the present invention, FIG. 4 is a diagram showing the results of the second embodiment corresponding to FIG. 2, and FIGS.
The figures are sectional views showing the third to sixth embodiments of the present invention, FIG. 9 is a sectional view showing the fourth embodiment of the invention, and FIG. 1O is an operational view of FIG. 9. 10... Base plate, I8 l111 rubber, 2011 @ top plate, 26-... engine, 281 diaphragm. 30...Liquid chamber, 32...Partition wall, 36...Vibration plate, 38...Restriction passage, 40...Cylindrical body, 42...Restriction passage, 4411 Movable plate, 48 Fist・Base Pro Nku, 64...Rubber. Agent Patent Attorney Atsushi Nakataka Figure 1 Figure 2 (B) Figure 3 Figure 4 (B) J Bao Zhou Figure 5 Figure 6 Figure 7 Figure 8 Figure 6

Claims (1)

[Claims] (1) A hollow chamber that can be expanded and contracted by an elastic material is used as a fluid chamber, and this hollow chamber is divided into three or more small fluid chambers by a plurality of partition walls, and one of the plurality of partition walls has a penetrating A vibration isolating device characterized in that a hole is provided as a first restriction passage, and the other part is formed as a second restriction passage between the outer periphery of the vibrating plate and a fixed peripheral wall.