JPH04327039A - Vibration isolator - Google Patents

Abstract

PURPOSE:To set either of two different vibration isolating characteristics without changing or adding parts with one vibration isolator. CONSTITUTION:At elastic body 30 has, on the outer circumferential part, a small recessed part 42 forming a second sub-liquid chamber 44 and a small recessed part 43 on the opposite side to a symmetry axis 11. A pressure receiving liquid chamber 36 is connected to the small recessed part 42 through a second communicating passage 54. In addition to a membrane 26 corresponding to the sub-liquid chamber 44, an outer cylinder 16 has a membrane 27 having a rigidity lower than the membrane 26 on the opposite side of the symmetry axis 11. When the elastic body 30 is inserted to the outer cylinder 16 and disposed thereon, the small recessed part 42 can be selectively conformed with either one of the membranes 26, 27 by changing the right and left sides to the asymmetry axis 11. When the case of conforming the membrane 26 with the small recessed part 42 is compared with the case of conforming the membrane 27 with the small recessed part 42, the frequency band in which a dynamic spring is reduced is closer to high frequency in a vibration isolator 10 in which the membrane 27 is conformed with the small recessed part.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid-filled bush type vibration isolator that absorbs vibrations from vibration-generating parts of an engine or the like.

0002

2. Description of the Related Art A vibration isolating device serving as an engine mount is disposed between the engine and the vehicle body of an automobile, and is designed to prevent engine vibrations from being transmitted to the vehicle body. Engine vibrations include shake vibrations and idle vibrations, which have different frequency ranges. Multiple liquid chambers are provided as a vibration isolator to absorb both of these vibrations, and the liquid passes between each liquid chamber. A liquid-filled vibration isolator that absorbs vibrations through resistance and liquid column resonance has been proposed (Japanese Unexamined Patent Publications Nos. 2-42226 and 2-42227).

In this liquid-filled vibration damping device, the vibration damping characteristics are tuned in accordance with the vibration characteristics of the engine to be supported in order to effectively absorb shake vibrations and idle vibrations. That is, tuning is performed so that the dynamic spring is reduced at the frequency that should be damped.

By the way, there are engines with different numbers of cylinders, such as 4 cylinders and 6 cylinders. For example, the idle vibration frequency of a 4-cylinder engine and a 6-cylinder engine is different.The idle vibration frequency of a 4-cylinder engine is approximately 23.3Hz (engine speed 700 rpm), and the idle vibration frequency of a 6-cylinder engine is approximately 23.3Hz (engine speed: 700 rpm). Approximately 35
Hz (engine speed: 700 rpm), and the frequency of the vibration to be damped is slightly different (note that the frequency also changes depending on the size of the engine). Therefore, a vibration isolator for a 4-cylinder engine and a vibration isolator for a 6-cylinder engine do not naturally have the same vibration isolation characteristics. One method of tuning the vibration damping characteristics is to change the rigidity of a diaphragm provided in the liquid chamber. Specifically, the frequency at which the dynamic spring constant is reduced is changed by changing the area of the diaphragm or changing the thickness of the rubber to change the rigidity of the diaphragm. Therefore, this vibration isolator is for 4-cylinder engines and 6-cylinder engines.
If it is applied to both cylinder and cylinder engines, it is necessary to prepare two types of diaphragms, which increases the number of diaphragm parts and requires two types of molds to mold the diaphragm, which increases costs. becomes.

[0005]

[Problems to be Solved by the Invention] Taking the above facts into consideration, the present invention provides a vibration isolator that can be set to one of two different vibration absorption characteristics without changing or adding any parts. That is the purpose.

[0006]

[Means for Solving the Problems] The vibration isolator of the present invention has an inner cylinder connected to one of the vibration generating part and the vibration receiving part, and an outer cylinder connected to the other of the vibration generating part and the vibration receiving part. , an elastic body provided between the inner cylinder and the outer cylinder and deformed when vibration occurs; a main liquid chamber that is expandable and contractible using the elastic body as at least a part of a partition; and a main liquid chamber connected to the main liquid chamber; a first recess that is disposed on one side of a predetermined axis of symmetry passing through the axes of the outer cylinder and the inner cylinder when viewed from the axial direction of the outer cylinder and the inner cylinder, and that opens on the outer cylinder side of the elastic body; a sub-liquid chamber formed by being surrounded by the outer cylinder, a first membrane body provided in the outer cylinder and elastically deformed facing the sub-liquid chamber, and the recess with respect to the axis of symmetry. a second recess that is disposed on the opposite side and opens toward the outer cylinder side of the elastic body; and the membrane body that is provided in the outer cylinder and is disposed on the opposite side of the membrane body with respect to the axis of symmetry. It is characterized by comprising a second membrane body having different rigidity.

[0007]

[Operation] In the vibration isolating device of the present invention, for example, when the outer cylinder is connected to the vibration receiving part and the inner cylinder is connected to the vibration generating part, the vibration transmitted from the vibration generating part is transmitted to the outer cylinder through the elastic body. Vibration is absorbed by resistance based on internal friction of the elastic body, and vibration is also absorbed by passage resistance of the liquid flowing between the main liquid chamber and the sub liquid chamber or by liquid column resonance.

[0008] Further, the elastic body is provided with a first recess connected to the main liquid chamber and a second recess disposed on the opposite side of the axis of symmetry, and the outer cylinder is provided with a first membrane and a second recess connected to the main liquid chamber. Since the second membrane body, which has a different rigidity from the first membrane body placed on the opposite side of the symmetry axis, is provided, when inserting the elastic body into the outer cylinder, the left and right direction with respect to the symmetry axis is By inserting them separately, either the first membrane body or the second membrane body can be made to correspond to the first recess. For example, if the rigidity of the second membrane body is set to be higher than the rigidity of the first membrane body, a vibration isolator in which the first membrane body corresponds to the first recess and a second membrane body Compared to a vibration isolator in which the second film body corresponds to the first recess, the vibration isolator in which the second membrane corresponds to the first recess reduces the dynamic spring in a higher frequency range. Therefore, this vibration isolator can be applied to different types of engines with different frequencies of idle vibration, such as a 4-cylinder engine and a 6-cylinder engine, by simply changing the assembly method.

[0009]

Embodiment An embodiment of the present invention will be described with reference to FIGS. 1 to 8.

As shown in FIG. 1, this vibration isolator 10 is equipped with a mounting frame 12 (not shown) for mounting on a vehicle body, and an outer cylinder 16 is inserted into an annular portion 14 of this mounting frame 12. There is. In this embodiment, the outer cylinder 16 is inserted into the annular part 14 with or without press fitting, and then fixed to the annular part 14 by caulking both ends of the annular part 14 inward. However, the outer cylinder 16 may be fixed to the annular part 14 by simply press-fitting the outer cylinder 16 into the annular part 14.

As shown in FIGS. 1 and 2, on the upper side of the outer cylinder 16, there is a symmetry axis 11 that passes through the axis and whose longitudinal direction is in the vertical direction in FIG. 1 (direction of arrow E and arrow F in FIG. 1). Left and right (
A pair of rectangular holes 18 (in the direction of arrow A and in the direction of arrow B) are formed. A small rectangular hole 20 is formed on the lower side of the outer cylinder 16 on the left side of the axis of symmetry 11 (in the direction of arrow A).
A small rectangular hole 21 is formed on the right side of 1 (in the direction of arrow B). Further, a thin rubber layer 22 is vulcanized and bonded to the inner peripheral surface of the outer cylinder 16, and portions of this thin rubber layer 22 corresponding to the rectangular holes 18 protrude inward to form a diaphragm 24, and a small A portion corresponding to the rectangular hole 20 protrudes inward to form a membrane 26 as a first membrane body, and a portion corresponding to the small rectangular hole 21 protrudes inward to form a second membrane body. A membrane 27 is formed. This membrane 27 is formed thinner than the membrane 26, and has lower rigidity against hydraulic pressure. Further, the membrane 27 and the membrane 26 have higher rigidity than the diaphragm 24.

An intermediate cylinder 28 is disposed coaxially inside the outer cylinder 16. The intermediate cylinder 28 is made of a steel plate, and as shown in FIGS. 3A and 3B, a pair of rings each having a substantially U-shaped cross section are connected to each other by a substantially semicircular connecting plate.

As shown in FIG. 4, an elastic body 30 is vulcanized and bonded to the intermediate cylinder 28, and an inner cylinder 31 is disposed approximately at the center of the elastic body 30 along the axis. The intermediate tube 28 is inserted into the outer tube 16, and after the outer tube 16 is squeezed, both ends of the outer tube 16 are caulked inward to be fixed to the outer tube 16. The elastic body 30 includes
A recess 34 is formed on the lower side of the inner cylinder 31 and at an intermediate portion in the axial direction, and the recess 34 and the outer cylinder 16 form a pressure-receiving liquid chamber 36 as a main liquid chamber. As shown in FIG. 5, the bottom surface 35 of the recess 34 has a substantially arc-shaped cross section perpendicular to the axis.

A movable body 64 made of an elastic material such as rubber is disposed in the pressure receiving liquid chamber 36 . The movable body 64 includes a movable part 65 and a pair of support legs 66 extending from the lower part of the movable part 65. The upper surface of the movable portion 65 has a shape corresponding to the bottom surface 35 of the recess 34 when viewed from the direction along the axis, and is formed so as to gradually separate from the bottom surface 35 as it approaches the side wall 37 of the recess 34. has been done. Further, the tip of the support leg 66 is inserted and fixed into a recess 68 formed near the opening of the recess 34. The movable portion 65 is biased toward the bottom surface 35 of the recess 34 by the biasing force of the support legs 66, and the center portion of the top surface of the movable portion 65 is lightly pressed against the bottom surface 35. Further, as shown in FIG. 5, the movable part 65 has side walls 39 of the recess 34 on both sides in the axial direction.
It is spaced a predetermined distance from.

On the other hand, on the upper side of the elastic body 30, as shown in FIG. A first sub-liquid chamber 40 is formed therein. Further, the space between the diaphragm 24 and the outer cylinder 16 is an air chamber. This air chamber may be communicated with the outside by forming a hole (not shown) in the annular portion 14 of the mounting frame 12.

Furthermore, a small recess 42 as a first recess is formed between the recess 34 and the recess 38 on the outer periphery of the elastic body 30 on the right side in FIG.
6 is fitted into the small recess 42, the outer cylinder 16, and the membrane 26 to form a second sub-liquid chamber 44 as a sub-liquid chamber. Further, on the outer periphery of the elastic body 30 on the left side in FIG.
is formed, and the membrane 27 is fitted into this small recess 43. In addition, the small recess 43 and the membrane 27
A dummy liquid chamber 46 is formed by the outer cylinder 16 and does not communicate with any other liquid chamber.

Further, the space between the membrane 26 and the outer cylinder 16 is an air chamber, and the annular part 14 of the mounting frame 12
A hole (not shown) may be formed in the hole to communicate with the outside.

As shown in FIG. 6, annular grooves 48 and 50 are formed on both sides of the recess 34, recess 38, and small recess 42 in the axial direction by rings of the intermediate cylinder 28, and these annular grooves 48 and 50 They are blocked from the outside by being closed by the outer cylinder 16, and the left side in FIG. 6 (in the direction of arrow C in FIG. 6) is the first communication path 52, and the right side in FIG. 6 (in the direction of arrow D in FIG. 6) is the second communication path 54. It is said that

As shown in FIG. 7, the first communication passage 52 is partially closed by the elastic body 30 and has a C-shaped cross section perpendicular to the axis, with one end connected to the second part of the pressure receiving liquid chamber 36. Sub-liquid chamber 4
The other end communicates with the pressure-receiving liquid chamber 36 through a hole 56 formed at the end of the first sub-liquid chamber 40 and the second sub-liquid chamber 44 . 1 sub-liquid chamber 40
It communicates with

As shown in FIG. 8, the second communication passage 54 is partially closed by the elastic body 30 and has a C-shaped cross section perpendicular to the axis, with one end connected to the second communication passage 54 of the pressure receiving liquid chamber 36. Sub-liquid chamber 4
The hole 60 formed at the fourth side end communicates with the pressure receiving liquid chamber 36, and the other end communicates with the pressure receiving liquid chamber 36 of the second sub liquid chamber 44.
It communicates with the second sub-liquid chamber 44 through a hole 62 formed at the 6th side end.

[0021] The pressure receiving liquid chamber 36, the first sub-liquid chamber 40, the second sub-liquid chamber 44, the first communication passage 52, and the second communication passage 54 are filled with liquid such as water or oil. .

Next, the assembly order of the vibration isolator 10 will be explained. As shown in FIG. 1, a block in which the inner cylinder 31, the elastic body 30, and the intermediate cylinder 28 are integrated is placed inside the outer cylinder 16 in a liquid.
Insert inside. At this time, the small recess 42 of the block
Insert the membrane 26 so that it corresponds to the . As a result, the pressure-receiving liquid chamber 36, the first sub-liquid chamber 40, the second sub-liquid chamber 44
The first communicating path 52 and the second communicating path 54 are evenly filled with liquid such as water or oil, and no air is mixed inside. Next, after squeezing the outer cylinder 16,
The vibration isolator 10 is completed by caulking both ends of the annular part 14, inserting the caulked outer cylinder 16 into the annular part 14 of the frame 12 (with or without press fitting), and caulking both ends of the annular part 14. Note that when the outer cylinder 16 is press-fitted into the annular portion 14, both ends of the annular portion 14 do not need to be caulked.

Next, the operation of this embodiment will be explained. When the frame 12 is attached to a vehicle body (not shown) and the inner cylinder 31 is connected to a six-cylinder engine (not shown), engine vibrations are supported by the vehicle body (not shown) via the inner cylinder 31, elastic body 30, outer cylinder 16, and frame 12. . At this time, the elastic body 30 is elastically deformed and engine vibrations are absorbed by a damping effect based on internal friction.

When the vibration of the engine is relatively low frequency (for example, shake vibration with a frequency of about 10 Hz and an amplitude of about ±1 mm), the liquid in the pressure receiving liquid chamber 36 flows through the first communicating path 52 to the first It goes back and forth with the sub-liquid chamber 40. At this time,
The membrane 26 of the second sub-liquid chamber 44 hardly deforms, and the volume of the second sub-liquid chamber 44 changes little, and no liquid flows through the second communication path 54. This is because the membrane 26 of the second sub-liquid chamber 44 has higher rigidity than the diaphragm 24 of the first sub-liquid chamber 40. Therefore, the shake vibration is absorbed by the passage resistance of the liquid in the first communicating path 52 or by the liquid column resonance. When the engine vibration frequency becomes a little high (idle vibration with a frequency of about 35Hz), the first
The communication path 52 becomes clogged. Therefore, the liquid in the pressure receiving liquid chamber 36 passes through the second communication path 54 and reaches the membrane 26.
is deformed to move back and forth between the pressure-receiving liquid chamber 36 and the second sub-liquid chamber 44. The dynamic spring constant is reduced by liquid column resonance within the second liquid communication path 54, and idle vibration is absorbed.

Furthermore, when the vibration frequency of the engine increases, the second communication passage 54 also becomes clogged, but the movable body 64
When the liquid resonates between the inner wall of the pressure-receiving liquid chamber 36 and the inner wall of the pressure receiving liquid chamber 36, the dynamic spring constant decreases again.

Although the above-mentioned vibration isolator 10 was assembled for a six-cylinder engine, the vibration-isolating characteristics of the vibration isolator 10 can be tuned for a four-cylinder engine by changing the way it is assembled. In this case, when inserting the block in which the inner cylinder 31, elastic body 30, and intermediate cylinder 28 are integrated into the outer cylinder 16, the membrane 27 is inserted so as to correspond to the small recess 42 of the block. . That is, the block is inserted after the axis of the outer cylinder 16 shown in FIG. 1 is rotated by 180 degrees. This allows the small recess 42 and the membrane 27, which has lower rigidity than the membrane 26, to
The second sub-liquid chamber 44 is configured in correspondence with the above. Note that in this embodiment, the resonance frequency of the liquid in the second communication path 54 is 23,
The stiffness of the membrane 27 is set to 3 Hz, which reduces the dynamic spring constant when the frequency is 23.3 Hz vibration.

Table 1 below shows the vibration isolation characteristics (relationship between vibration frequency and dynamic spring constant) of the vibration isolator 10 assembled for a 6-cylinder engine and the vibration isolator 10 assembled for a 4-cylinder engine. Show the graph shown.

[0028]

[Table 1] In this embodiment, the wall thickness is increased as a method of making the rigidity of the membrane 26 higher than that of the membrane 27, but the present invention is not limited to this, and as shown in FIG. 9, the wall thickness is increased. The thickness and area may be the same, and a cord layer 94 (cloth made of synthetic fiber, etc.) may be embedded inside to increase the rigidity of the membrane 26. Further, as shown in FIG. 10, the size (opening area) of the small rectangular hole 20 is made smaller than the small rectangular hole 21, and the size of the membrane 26 (the area facing the liquid) is made smaller than the membrane 27. By doing so, the rigidity of the membrane 26 may be increased. Furthermore, the rigidity of the membrane 26 may be increased by appropriately combining the wall thickness, area, buried objects, etc.

Furthermore, in this embodiment, a 4-cylinder engine and a 6-cylinder engine are used.
Although the rigidity of the membrane 26 and the membrane 27 is set so as to correspond to the cylinder engine, the present invention is not limited to this, and the type of engine to which it is applied does not matter.

Furthermore, in this embodiment, the frequency at which the moving spring is reduced is set to be selectable from either 23, 3 Hz or 35 Hz, but the present invention allows the frequency at which the moving spring is reduced to be set to either 23, 3 Hz or 35 Hz. It is not limited to.

Furthermore, in this embodiment, the second sub-liquid chamber 44 is configured to communicate with the pressure-receiving liquid chamber 36 without going through another liquid chamber (first sub-liquid chamber 40); 44 may be configured to communicate with the pressure-receiving liquid chamber 36 via another liquid chamber (first sub-liquid chamber 40), or the first sub-liquid chamber 40 may communicate with another liquid chamber (second sub-liquid chamber 40).
It may be configured to communicate with the pressure-receiving liquid chamber 36 via a sub-liquid chamber 44).

[0032]

[Effects of the Invention] Since the vibration isolating device of the present invention has the above structure, it has an excellent effect that it can be set to one of two different vibration absorption characteristics without changing or adding any parts. .

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view showing a vibration isolator according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG. 1, showing an outer cylinder and a thin rubber layer of the vibration isolator according to the embodiment of the present invention.

FIG. 3 shows an intermediate cylinder of a vibration isolator according to an embodiment of the present invention, where A is a cross-sectional view taken along the line IIIA-IIIA in FIG. 3B, and B is a cross-sectional view in FIG. 3A.
It is a IIIB-IIIB line sectional view of.

4 shows a vibration isolator according to an embodiment of the present invention, and is a cross-sectional view taken along the line IV-IV in FIG. 5. FIG.

FIG. 5 shows a vibration isolator according to an embodiment of the present invention, and is a cross-sectional view taken along the line V-V in FIG. 4.

FIG. 6 is a partial cross-sectional view corresponding to FIG. 4, showing a vibration isolating device according to an embodiment of the present invention.

7 shows a vibration isolator according to an embodiment of the present invention, and is a sectional view taken along the line VII-VII in FIG. 6. FIG.

8 shows a vibration isolator according to an embodiment of the present invention, and is a sectional view taken along the line VIII-VIII in FIG. 6. FIG.

FIG. 9 is a sectional view perpendicular to the axis showing a membrane of a vibration isolator according to another embodiment of the present invention.

FIG. 10 is a sectional view perpendicular to the axis showing a membrane of a vibration isolator according to another embodiment of the present invention.

[Explanation of symbols]

10 Vibration isolator 11 Axis of symmetry 16 Outer tube 26 Membrane (first membrane) 27 Membrane (second membrane) 30 Elastic body 31 Inner tube 36 Pressure-receiving liquid chamber (main liquid chamber) 42 Small recess (first 43 Small recess (second recess) 44 Second sub-liquid chamber (sub-liquid chamber)

Claims (1)

[Claims] 1. An inner cylinder connected to one of a vibration generating part and a vibration receiving part, an outer cylinder connected to the other of the vibration generating part and a vibration receiving part, and a space between the inner cylinder and the outer cylinder. an elastic body that is provided and deforms when vibration occurs; a main liquid chamber that is expandable and contractible using the elastic body as at least a part of a partition; and a main liquid chamber that is connected to the main liquid chamber and that is viewed from the axial direction of the outer cylinder and the inner cylinder. a first recess that is disposed on one side of a predetermined axis of symmetry that passes through the axes of the outer cylinder and the inner cylinder, and is surrounded by the outer cylinder, and has a first recess that is open to the outer cylinder side of the elastic body; a liquid chamber, a first film body provided in the outer cylinder and elastically deformed facing the sub-liquid chamber, and the outer cylinder of the elastic body disposed on the opposite side of the recess with respect to the axis of symmetry. a second recess opening on the side; and a second membrane body provided in the outer cylinder and disposed on the opposite side of the membrane body with respect to the axis of symmetry and having a different rigidity from the membrane body. A vibration isolating device characterized by being equipped with.