JPH07269641A - Liquid-seal bush - Google Patents

Abstract

PURPOSE:To prevent abnormal sound from being generated by preventing bubbles from passing an orifice even if air enters or bubbles are generated in a liquid-seal bush. CONSTITUTION:A liquid-seal bush wherein vibration inputting direction is lateral direction is taken as an object, and a pair of liquid chambers 4a, 4b into which liquid L is sealed are formed in both side positions where an inner cylindrical body is pinched from the right and the left as the vibration inputting direction by connecting the inner cylindrical body 1 and an outer cylindrical body 2 to each other by an elastic body 3. An orifice 5 is formed between an elastic body part 33b on the lower side of the inner cylindrical body and an inner peripheral surface 2a of the outer cylindrical body, and both liquid chambers are communicated with each other at the lowermost part, so as to prevent entered bubbles or generated bubbles accumulated on the upper part 41 from passing through the orifice. A protrusion is provided in the lowermost position of the inner cylindrical body of the elastic body end surface in the cylinder axis X direction, and chamfering parts 81 are provided in the upper position of a rubber layer 8 on the outer peripheral surface of the outer cylindrical body, and tongue pieces are provided in the lower position, so as to be taken as a display means 9 for displaying positioning in the connection, so that the orifice may be reliably arranged in the lowermost position.

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 used for a suspension bush such as a lower arm bush of an automobile, for damping vibrations input to the inner cylinder or the outer cylinder in the left-right direction. .

[0002]

2. Description of the Related Art Conventionally, as this type of liquid enclosing bush, a pair of liquid chambers defined inside an elastic body and an orifice for communicating the pair of liquid chambers with each other are provided. It is known that the vibration of the liquid column is damped by the liquid column resonance (for example, in Japanese Utility Model Laid-Open No. 61-1728).
No. 07). In this structure, an inner cylindrical body connected to one of the vibration source or the vibration receiving portion and an outer cylindrical body connected to the other are connected to each other by an elastic body, and at both positions of the elastic body in the vibration input direction. While liquid chambers are formed at both left and right positions sandwiching an inner cylinder, orifices penetrating in the left and right directions are provided in elastic bodies at both upper and lower positions sandwiching the inner cylinder.

[0003]

However, the pair of liquid chambers and the pair of orifices of the above-mentioned conventional liquid enclosing bush are originally enclosed by, for example, a vacuum suction method so as to be filled with the liquid. In the liquid filling process,
Occasionally, air may be mixed in and the air may accumulate at the upper part of the liquid chamber. When air accumulates in the upper part, when the vibration is input, the air flows into the liquid along with the flow of the liquid, and the liquid containing the air bubbles flows between the left and right liquid chambers through the upper orifice. To do. Then, noise may occur due to cavitation when passing through the upper orifice.

Further, when the liquid to be sealed is a highly viscous liquid such as silicone oil, even if air is completely prevented from being mixed in in the liquid sealing process performed at room temperature,
When the temperature becomes low, a volume change occurs due to the compressibility of the highly viscous liquid itself, and the air content dissolved in the liquid may be separated to become micro bubbles in the liquid and become visible. Then, the micro bubbles rise in the liquid chamber toward the upper orifice, and the micro bubbles cause an abnormal noise due to cavitation as described above at the time of vibration input.

The present invention has been made in view of the above circumstances, and an object thereof is to allow a bubble to pass through an orifice even if air is mixed or bubbles are generated in a liquid sealing bush. This is to prevent the occurrence of abnormal noise.

[0006]

In order to achieve the above object, the invention according to claim 1 is such that an inner cylindrical body connected to one of a vibration source and a vibration receiving portion, and the inner cylindrical body is surrounded. An outer cylindrical body that is arranged and is connected to the other of the vibration generating source and the vibration receiving section, and the outer cylindrical body and the inner cylindrical body that are interposed between the outer cylindrical body and the inner cylindrical body, An elastic body to connect,
It is assumed that the elastic body is provided with a pair of liquid chambers defined at both positions in the vibration input direction sandwiching the inner cylinder body and filled with a liquid, and an orifice communicating the pair of liquid chambers with each other. . In this configuration, the vibration is generated in the inner cylinder and the outer cylinder so that the vibration input direction is a substantially horizontal direction orthogonal to the cylinder axis of the inner cylinder, and is a horizontal direction sandwiching the inner cylinder. Connected to the source or vibration receiver,
The pair of liquid chambers are arranged on both sides in the left-right direction with the inner cylinder interposed therebetween. Further, the orifice is formed only at a position at least lower than the inner cylindrical body.

According to a second aspect of the invention, in the invention according to the first aspect, the orifice is provided between the outer peripheral surface of the elastic body below the inner cylindrical body and the inner peripheral surface of the outer cylindrical body. It is configured to be formed along.

According to a third aspect of the present invention, in the first aspect of the invention, display means for displaying the connection position so that the orifice is located below the inner cylinder when the inner cylinder or the outer cylinder is connected. Is provided on the outer surface.

Further, the invention according to claim 4 is the same as claim 1.
In the described invention, the liquid is a highly viscous liquid.

[0010]

With the above construction, in the invention according to claim 1,
When vibration is applied to the inner cylinder or the outer cylinder from the left-right direction, the elastic body deforms so that one of the pair of left and right liquid chambers expands and the other contracts. Liquid flow occurs between them, and vibration is attenuated by liquid column resonance through the orifice. At this time, since the orifice through which the liquid flows is arranged at least at a position lower than the inner cylindrical body, air bubbles are mixed in the liquid chamber during the liquid sealing process during manufacturing, or the temperature condition shifts to a low temperature state. Accordingly, even if the air dissolved in the liquid itself is separated and micro bubbles are generated, those bubbles ascend in the liquid chamber and accumulate in the upper portion, and the bubbles do not flow in the orifice. As a result, it is possible to reliably prevent the generation of abnormal noise due to the cavitation phenomenon due to the bubbles passing through the orifice.

According to the second aspect of the present invention, in addition to the effect of the first aspect of the invention, the orifice is provided between the outer peripheral surface of the elastic body and the inner peripheral surface of the outer cylindrical body below the inner cylindrical body. Since it is formed along the outer cylindrical body, its orifice is located at the lowermost part of the liquid chamber, so that air bubbles are more reliably prevented from being mixed into the liquid flowing in the orifice. As a result, the generation of abnormal noise is more reliably prevented.

According to the invention described in claim 3, in addition to the action according to the invention described in claim 1, when the inner cylinder and the outer cylinder are connected to the vibration source or the vibration receiving portion, the outer surface is By positioning the connecting position based on the display means provided, the orifice can be reliably positioned below the inner cylinder. As a result, the operation according to the invention described in claim 1 can be surely obtained.

Further, according to the invention described in claim 4, in addition to the operation according to the invention described in claim 1, since the liquid enclosed in the liquid chamber is a highly viscous liquid, the microscopic reaction is performed from the highly viscous liquid itself particularly in a low temperature state. Even if bubbles are generated, the orifice is arranged at a position lower than the inner cylinder, so that the micro bubbles can be prevented from passing through the orifice.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a liquid-filled bush according to an embodiment of the present invention, where 1 is an inner cylinder, and 2 is a cylinder shaft of the inner cylinder 1 at a predetermined distance on the outer peripheral side of the inner cylinder 1. An outer cylindrical body 3 arranged coaxially with X is interposed between the outer cylindrical body 2 and the inner cylindrical body 1, and elastic bodies 4a, 4b for joining and connecting the both 1 and 2 with each other. Is a substantially horizontal direction that is orthogonal to the cylinder axis X and sandwiches the inner cylinder 1 from the left and right (see FIG. 1).
Left and right direction; hereinafter, simply referred to as left and right direction) A pair of liquid chambers formed at respective positions on both sides, and 5 is a pair of liquid chambers 4
It is an orifice that connects a and 4b to each other.

A stopper member 6 projecting to the left and right is integrally fixed to the outer peripheral surface of the inner cylindrical body 1 at the center position in the cylinder axis X direction, and both protruding ends of the stopper member 6 are the outer cylinder. It projects toward the liquid chambers 4a, 4b to a position spaced from the inner peripheral surface 2a of the body 2 by a predetermined distance. When the excessive impact force acts on the stopper member 6 in the vertical direction, the projecting ends of the stopper member 6 come into contact with the inner peripheral surface 2a of the outer cylindrical body 2 so that the inner cylindrical body 1 and the outer cylindrical body 2 can be further protected. It prevents the occurrence of relative displacement.

As shown in FIGS. 2 and 3, the elastic body 3 is provided with a reinforcing cylinder 7 with a window at the outer peripheral side position. When the reinforcing cylinder 7 is embedded in the outer peripheral side position, rubber is added. It is formed by vulcanization. Then, the elastic body 3 is
It is integrally connected to the outer cylinder body 2 by being press-fitted into the outer cylinder body 2 via a rubber layer 31 vulcanized and bonded to the outer peripheral surface of the reinforcement cylinder 7. Windows 7a and 7b are formed on both sides of the reinforcing cylinder 7 in the left-right direction.
The elastic body 3 at a position corresponding to a or 7b is provided with recesses 32, 32 serving as liquid chamber spaces. And
The two recesses 32, 32 and the inner peripheral surface 2a of the outer cylinder 2 define the two liquid chambers 4a, 4b, and are orthogonal to the direction connecting the two liquid chambers 4a, 4b. Elastic body portions 33a and 33b for elastically supporting the inner cylinder body 1 and the outer cylinder body 2 to each other are formed on both sides in a substantially vertical direction (vertical direction in FIG. 1; hereinafter simply referred to as vertical direction). Further, on the end surface of the elastic body 3 in the cylinder axis X direction, as shown in FIG.
A projection 35 for positioning is integrally formed at the lowermost position around the circumference.

A liquid L having a high viscosity (for example, 100 centistokes) such as silicon oil is filled in the liquid chambers 4a and 4b in a filled state by a filling means such as a vacuum suction method. In addition, the orifice 5 has a lower elastic body portion 3
3b is defined by the concave groove 34 formed in the rubber layer 31 on the outer peripheral surface of 3b and the inner peripheral surface of the outer cylindrical body 2, and the orifice 5 causes liquid column resonance due to vibration of a predetermined frequency. Is tuned to. That is, the orifice 5 is provided only at a position lower than the inner cylindrical body 1, and is provided along the lowermost inner peripheral surface 2a of the outer cylindrical body 2 so as to close both the liquid chambers 4a and 4b. It is designed to communicate at the bottom.

A rubber layer 8 having a predetermined shape is integrally vulcanized and adhered to the outer peripheral surface of the outer cylindrical body 2 of the liquid-filled bush having such a structure. The rubber layer 8 is formed by a chain double-dashed line in FIGS. 1 to 3 or, as shown in FIG. 4, formed into a substantially square shape having a horizontal cross section facing outward in the vertical and horizontal directions.
Chamfers 81, 81 are formed at both upper and right corners. Further, a tongue piece 82 projecting downward is integrally formed at the lowermost position of the end portion of the rubber layer 8 in the cylinder axis X direction.
The upper inner peripheral surface of the mounting portion of the lower arm 12 to be mounted on the outer cylinder body 2 side of the liquid sealing bush is formed in a shape corresponding to the chamfered portions 81, 81. The outer cylindrical body 2 is connected to the outer cylindrical body 2 through the rubber layer 8 having the substantially square cross section.

By the projection 35, the tongue piece 82, or the chamfered portion 81, the display means 9 for displaying the mounting position in the circumferential direction around the cylinder axis X when the liquid-filled bush is mounted on an automobile or the like is provided. It is configured.

Next, the operation and effect of the embodiment having the above configuration will be described.

In the liquid-filled bush, the outer cylindrical body 2 is connected to the vibration source, for example, the tire side of an automobile,
The inner cylinder 1 is connected to the vibration receiving portion, for example, on the vehicle body side of an automobile. Specifically, as shown in FIG. 5, the liquid-sealed bushes S move in the front-rear direction along the cylinder axis X with respect to the front and rear end portions of the A-shaped lower arm 12 that constitutes the front suspension 11 that supports the front wheels 10 of the automobile. The outer cylinder 2 is connected to the lower arm 12 side, and the inner cylinder 1 is connected to the vehicle body 13 side. At the time of this connection, the operator attaches the tongue pieces 82 downward, or attaches the chamfered portions 81 so as to fit the inner peripheral surface of the attachment portion of the lower arm 12 to each liquid. The respective liquid enclosing bushes S can be connected in a state where the orifice 5 inside the enclosing bush S is surely positioned at the lowermost portion. Moreover, since the tongue piece 82 is provided in addition to the chamfered portions 81, the tongue piece 8 as described above is provided.
When there is no 2, the worker attaches the rubber layer 8 to the lower arm 12
It is possible to reliably prevent the occurrence of the positional displacement of the orifice 5 due to the forced press-fitting with respect to the mounting portion in a state displaced from the predetermined circumferential position.

The front wheel 9 is supported on the vehicle body 13 through a pair of liquid-filled bushes S, S, and swings in the vertical and longitudinal directions when the front wheel 9 passes through the unevenness of the road surface during traveling. However, the vibration force in the direction indicated by the solid arrow in the figure acts on the lower arm 12 mainly on the basis of the rocking in the front-rear direction, so that the liquid-filled bush S is vibrated in the left-right direction which is the vehicle width direction. Will work. Then, when vibration is input from the lower arm 12 to the outer tubular body 2 in the left-right direction in FIG. 1 and a force that relatively displaces the outer tubular body 2 in the left-right direction with respect to the inner tubular body 1, both The elastic body portions 33a and 33b are bent to reduce the liquid chamber 4a or 4b on one side in the left-right direction and the liquid chamber 4 on the other side.
b or 4a is enlarged, and the liquid L flows through the orifice 5 between the liquid chambers 4a and 4b. As a result of this flow, liquid column resonance occurs in a predetermined frequency range that is the tuning frequency of the orifice 5, and the vibration can be damped by the liquid column resonance.

In the process of filling the liquid L when manufacturing the liquid filling bush S, air other than the liquid L is supplied to the liquid chamber 4
When mixed in a and 4b, the air is mixed in both liquid chambers 4a and 4b.
The upper part 4 of each liquid chamber 4a, 4b that rises in the liquid L in b and is surrounded by the upper elastic body portion 33a and the inner peripheral surface 2a of the outer cylindrical body 2.
1 (see FIG. 1). Even in this case, both liquid chambers 4
Since the orifice 5 communicating with the liquid chambers a and 4b is provided at the lowermost position of the liquid chambers 4a and 4b, the flow of the liquid L between the liquid chambers 4a and 4b is caused by the input of the left-right vibration. Also, it is possible to reliably prevent the bubbles from the air from being mixed in the liquid L passing through the orifice 5. As a result, it is possible to prevent a decrease in the flow amount of the liquid L caused by the inclusion of bubbles in the liquid L passing through the orifice 5 and prevent the deterioration of the damping characteristic. It is possible to reliably prevent the generation of abnormal noise due to cavitation caused by the inclusion of air bubbles in the liquid L that is generated.

On the other hand, even if the step of enclosing the liquid L is performed at room temperature without any air inclusion, the air dissolved in the liquid L itself separates in the liquid L at low temperature. Micro bubbles may occur in the. Even in this case, the generated micro-bubbles are
As it goes up in 4b and accumulates in the upper part 41,
Similar to the case of mixing air, it is possible to reliably prevent the micro bubbles from being mixed in the liquid L that passes through the orifice 5, and it is possible to prevent deterioration of the damping characteristic and noise. It is possible to reliably prevent the occurrence of.

When the integrally molded product of the inner cylinder 1 and the elastic body 3 is press-fitted into the outer cylinder 2 integrally formed with the chamfers 81, 81, the outer cylinder 2 is chamfered. 8
A state in which the orifice 5 is surely positioned at the lowermost portion by press-fitting the integrally molded product in which the projections 35 are disposed on the lower side of the outer cylindrical body 2 is press-fitted in such a manner that 1, 1 are disposed on the upper side. Can be assembled on.

The present invention is not limited to the above embodiment, but includes various other modifications. That is, although the rubber layer 8 is formed on the outer peripheral surface of the outer cylindrical body 1 in the above-mentioned embodiment, the present invention is not limited to this, and the rubber layer 8 is not limited to this.
It may be omitted as shown by the solid line in FIG. In this case, the projection 35 constitutes the display means 9, and when connecting to the automobile, the orifice 5 can be surely placed in the lowermost position by positioning based on the projection 35. it can.

In the above embodiment, the tongue piece 8 is used as the display means 9.
Although the chamfered portion 81 is provided in addition to 2, the display means may be configured by only one of them.

In the above-described embodiment, the orifice 5 is provided between the lowermost end of the lower elastic body portion 33b and the peripheral surface 2a of the outer cylindrical body 2. However, the orifice 5 is not limited to this, and each orifice is provided in each liquid chamber. Four
It suffices that the air accumulated in the upper portion 41 of the a and 4b is formed at a position where it does not enter the orifice as the liquid L flows. Therefore, if the orifice is formed at least below the inner cylinder 1. Good. In addition, the number of orifices may be two or more as long as it is below the inner cylinder 1.

In the above embodiment, the high-viscosity liquid L is sealed, but the invention is not limited to this, and a low-viscosity liquid may be sealed. Also in this case, the same effect as in the case of high viscosity can be obtained.

Further, in the above embodiment, the inner cylinder body 1 is replaced by the vehicle body 1.
The outer cylindrical body 2 is connected to the side of 3 (vibration receiving portion) and the side of the front wheel 10 (vibration generation source), respectively. However, the present invention is not limited to this.

Further, in the above embodiment, the case where it is used as the lower arm bush for connecting the lower arm 12 and the vehicle body 13 of the automobile is shown, but the present invention is not limited to this, and the exciting force acts on the liquid-filled bush in the left-right direction. Anything may be used as a bush for other purposes.

[0033]

As described above, according to the liquid-filled bush in the first aspect of the invention, a pair of liquid chambers are sandwiched between the left and right sides of the inner cylindrical body for the case where the vibration input direction is the left-right direction. Since the orifice that is formed at the position and connects the pair of liquid chambers is arranged only on the lower side of the inner cylindrical body, air bubbles are mixed in the liquid chamber during the liquid sealing step during manufacturing, Even if the air dissolved in the liquid itself separates and micro bubbles are generated as the temperature condition shifts to a low temperature state, those bubbles rise in the liquid chamber and accumulate at the upper part, and bubbles inside the orifice are formed. It can be surely prevented from passing. As a result, it is possible to reliably prevent the generation of abnormal noise due to cavitation that accompanies the liquid mixed with bubbles passing through the orifice.

According to the second aspect of the invention, in addition to the effect of the first aspect of the invention, since the orifice is formed along the inner peripheral surface of the outer cylindrical body, the orifice is located in the uppermost part of the liquid chamber. Since it can be located at the lower portion, it is possible to more reliably prevent the occurrence of a situation in which the liquid containing bubbles passes through the orifice, and as a result, it is possible to more reliably prevent the generation of abnormal noise.

According to the invention of claim 3, in addition to the effect of the invention of claim 1, in connecting the inner cylindrical body and the outer cylindrical body to the vibration source or the vibration receiving portion, The connecting position can be positioned based on the display means provided on the outer surface, and the orifice can be surely placed in the lower side of the inner cylindrical body. As a result, it is possible to surely obtain the effect according to the invention described in claim 1.

Further, according to the invention described in claim 4, in addition to the effect according to the invention described in claim 1, since the liquid enclosed in the liquid chamber is a high-viscosity liquid, the micro-temperature is particularly high when shifting to a low temperature state. Even if a situation occurs in which bubbles are generated, since the orifice is arranged at a position lower than the inner cylindrical body, it is possible to prevent the micro bubbles from passing through the orifice, which is particularly useful. Become.

[Brief description of drawings]

FIG. 1 is a partially omitted horizontal cross-sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB in FIG.

FIG. 4 is a perspective view of the embodiment of FIG.

FIG. 5 is a simplified plan view showing how the embodiment of FIG. 1 is mounted on an automobile.

[Explanation of symbols]

 1 Inner Cylinder 2 Outer Cylinder 2a Inner Circumferential Surface of Outer Cylinder 3 Elastics 4a, 4b Liquid Chamber 5 Orifice 9 Display Means 10 Front Wheel (Vibration Source) 13 Car Body (Vibration Receiving Section) 35 Protrusion (Display Means) 81 Chamfer (display means) 82 Tongue piece (display means) L liquid X tube axis

Claims (4)

[Claims] 1. An inner cylindrical body connected to one of a vibration generating source and a vibration receiving section, and an outer cylindrical body arranged to surround the inner cylindrical body and connected to the other of the vibration generating source and the vibration receiving section. And an elastic body interposed between the outer cylinder body and the inner cylinder body to connect the outer cylinder body and the inner cylinder body to each other, and both sides of the elastic body in the vibration input direction sandwiching the inner cylinder body. In a liquid-filled bush having a pair of liquid chambers defined in positions and filled with liquid, and an orifice communicating with the pair of liquid chambers, the vibration input direction is orthogonal to the cylinder axis of the inner cylinder. The inner cylindrical body and the outer cylindrical body are respectively connected to the vibration source or the vibration receiving portion so as to be in a horizontal direction which is a substantially horizontal direction with the inner cylindrical body sandwiched therebetween, and the pair of liquid chambers includes the inner cylinder. They are located on both sides in the left-right direction across the body, and the orifice is Fluid-filled bushing, characterized in that it is formed only on at least a lower position than the body. 2. The liquid seal according to claim 1, wherein the orifice is formed along the outer cylinder between the outer peripheral surface of the elastic body below the inner cylinder and the inner peripheral surface of the outer cylinder. bush. 3. The liquid-filled bush according to claim 1, wherein the outer surface is provided with display means for displaying the connection position so that the orifice is located below the inner cylinder when the inner cylinder or the outer cylinder is connected. 4. The liquid-filled bush according to claim 1, wherein the liquid is a highly viscous liquid.