JP2009103223A - Vibration damper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine mount 10 capable of inhibiting cavitation while achieving low cost and saving space. <P>SOLUTION: This engine mount includes an inner tube member 16 connected to an engine, an outer tube member 14 connected to a vehicle body 16, an elastic body 18 elastically supporting the inner tube member 16 and the outer tube member 14, an orifice passage 114 providing communication between a main liquid chamber 84 and an auxiliary liquid chamber 86, a membrane member 75 deforming according to pressure difference between the main liquid chamber 84 and the auxiliary liquid chamber 86, and a coil spring 140 urging the membrane member 75 toward the auxiliary liquid chamber 86 from the main liquid chamber 84. The coil spring 140 is formed so as to surface the membrane member 75 and provide communication between the main liquid chamber 84 and the auxiliary liquid chamber 86 if pressure of the main liquid chamber 84 is not greater than a predetermined value. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vibration isolator.

  An engine mount is disposed between the engine that is the vibration generating unit of the vehicle and the vehicle body that is the vibration receiving unit as a vibration isolator that suppresses transmission of engine vibration to the vehicle body. The engine mount includes an inner cylinder connected to the engine, an outer cylinder connected to the vehicle body, an elastic body that closes one end of the outer cylinder while connecting the inner cylinder and the outer cylinder, and the other end of the outer cylinder. And a partition member that partitions the inside of the outer cylinder into a main liquid chamber on the elastic body side and a sub liquid chamber on the diaphragm side, and an orifice that communicates the main liquid chamber and the sub liquid chamber.

  In the conventional engine mount described above, a load in the direction in which the liquid pressure in the main liquid chamber increases (hereinafter referred to as “bound load”) is input, and then a load in the direction in which the liquid pressure in the main liquid chamber decreases (hereinafter “ When “rebound load” is input and a sudden pressure fluctuation is applied in the main liquid chamber, the negative pressure in the main liquid chamber increases instantaneously (the pressure in the main liquid chamber is extremely small). Thereby, a part of the liquid in the main liquid chamber is vaporized to generate bubbles (cavitation). And when the negative pressure is eliminated and the bubbles disappear, there is a problem that abnormal noise is generated.

In Patent Documents 1 and 2, a through-hole that allows the two fluid chambers to communicate with each other is provided in the partition member, and a movable plate that can block the entire through-hole is movable between the two fluid chambers. Techniques for placement are described. In this technique, the negative pressure in the main liquid chamber is relieved by the movement of the movable plate.
In Patent Document 3, a short-circuit path for short-circuiting the orifice passage is provided so as to open on the pressure receiving chamber side surface of the partition member, while a valve body for switching the short-circuit path between the communication state and the shut-off state is provided. A technique for providing a metal spring that is held in an interrupted state with an initial elastic deformation amount is described. As a result, the significant negative pressure induced in the pressure receiving chamber when a shocking large load of vibration is input can be eliminated as quickly and reliably as possible, resulting in large vibrations and abnormal noise caused by gas phase separation in the pressure receiving chamber. It is described that generation | occurrence | production of can be prevented.
JP 2006-97823 A JP 2006-250281 A JP 2007-107712 A

However, in the techniques described in Patent Documents 1 and 2, when the movable plate moves and blocks the entire through hole, the negative pressure in the main liquid chamber increases again. Therefore, it is difficult to suppress the occurrence of cavitation.
Moreover, in the technique described in Patent Document 3, since a valve body different from the existing parts is provided, there are problems that the number of parts increases, costs increase, and space efficiency decreases.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a vibration isolator capable of suppressing the occurrence of cavitation at low cost and space saving.

The present invention employs the following means in order to solve the above problems.
The vibration isolator according to the present invention is connected to one of the vibration generating part and the vibration receiving part, and is formed in a substantially cylindrical shape, and the other of the vibration generating part and the vibration receiving part. And a second mounting member disposed on the inner peripheral side of the first mounting member, an elastic body that elastically supports a space between the first mounting member and the second mounting member, and a partition wall A main liquid chamber in which a part is composed of the elastic body, a liquid is enclosed, and a part of a partition wall is composed of a diaphragm, and a liquid is enclosed, and a secondary liquid whose internal volume can be expanded and contracted according to a change in liquid pressure A partition member provided between the main liquid chamber and the sub liquid chamber, an orifice passage communicating the main liquid chamber and the sub liquid chamber, the main liquid chamber and the sub liquid chamber, A membrane member that deforms in response to a pressure difference between the membrane member and the membrane member And a biasing member that biases the main liquid chamber toward the sub liquid chamber, and the biasing member displaces the membrane member when the pressure of the main liquid chamber becomes a predetermined value or less. The main liquid chamber and the sub liquid chamber are formed so as to communicate with each other.

  According to this configuration, when the pressure in the main liquid chamber becomes a predetermined value or less, it becomes possible to allow the liquid to flow from the sub liquid chamber into the main liquid chamber, thereby eliminating the negative pressure in the main liquid chamber. it can. Therefore, the occurrence of cavitation can be prevented. In addition, as compared with the vibration isolator according to the prior art, it can be configured only by changing the shape, except that an urging member is added, and an increase in manufacturing cost and a decrease in space efficiency can be suppressed.

The membrane member is biased by the biasing member so as to close a through hole formed in the partition member, and the membrane member includes a ring member having a diameter larger than that of the through hole. To do.
According to this configuration, even when the membrane member is largely deformed, the ring member does not pass through the through hole, so that the membrane member can be prevented from falling off the through hole.

The biasing member is formed integrally with the membrane member.
According to this structure, compared with the engine mount which concerns on a prior art, it can be comprised without an additional member, and it becomes possible to suppress the increase in manufacturing cost to the minimum.

  According to the present invention, as compared with the vibration isolator according to the prior art, it can be configured only by changing the shape except for adding an urging member, while suppressing an increase in manufacturing cost and a decrease in space efficiency. The occurrence of cavitation can be prevented.

Hereinafter, an engine mount according to an embodiment of a vibration isolator according to the present invention will be described with reference to the drawings.
(Engine mount)
FIG. 1 is a cross-sectional view showing the overall configuration of the engine mount in the present embodiment.
As shown in FIG. 1, an engine mount (anti-vibration device) 10 supports an engine that is a vibration generating unit in an automobile to a vehicle body that is a vibration receiving unit. In the following description, symbol S in the figure indicates the axis of the engine mount 10, and the direction along the axis S is the axial direction of the engine mount 10.

  The engine mount 10 includes a cylindrical outer cylinder member (first attachment member) 14, an inner cylinder member (second attachment member) 16 disposed substantially coaxially above the inner peripheral side of the outer cylinder member 14, An elastic body 18 made of a rubber material or the like that elastically supports between the outer cylinder member 14 and the inner cylinder member 16 is provided.

  A cylindrical large diameter portion 28 is formed at the upper end portion of the outer cylinder member 14, and a cylindrical small diameter portion 30 having a smaller diameter than the large diameter portion 28 is formed at the lower end side. Between the large-diameter portion 28 and the small-diameter portion 30, a throttle portion 32 that is reduced in diameter toward the inner peripheral side is formed over the entire circumference.

  The inner cylinder member 16 is a bullet-shaped member, and a connecting portion 22 extending along the axis S is formed on the upper portion thereof. A screw hole 24 is formed at the center of the connecting portion 22. Bolts 26 are screwed into the screw holes 24 to fix an engine side bracket (not shown), and the inner cylinder member 16 is fastened and fixed to the engine side via the engine side bracket. On the other hand, a tapered portion 21 that tapers downward is formed on the lower side of the inner cylinder member 16. And between the connection part 22 and the taper part 21, the anchor part 20 which protrudes to the radial direction outer side of the inner cylinder member 16 is formed.

  The elastic body 18 has an outer peripheral surface vulcanized and bonded to the inner peripheral side of the large diameter portion 28 and the throttle portion 32 in the outer cylindrical member 14, and an inner peripheral surface is added to the outer peripheral side of the tapered portion 21 in the inner cylindrical member 16. Sulfur bonded. Thereby, the inner cylinder member 16 and the outer cylinder member 14 are elastically connected. An inner ring 35 that penetrates through the elastic body 18 is provided between the outer cylinder member 14 and the inner cylinder member 16 so as to surround the periphery of the tapered portion 21 in the inner cylinder member 16. Further, the upper end portion of the inner peripheral surface of the elastic body 18 is extended so as to wrap around the anchor portion 20 to form a rebound stopper mechanism.

  On the other hand, a cylindrical diaphragm support member 80 is fitted on the inner peripheral side of the small diameter portion 30 of the outer cylinder member 14. On the inner peripheral side of the diaphragm support member 80, a bowl-shaped diaphragm 82 made of an elastic material such as rubber is vulcanized and bonded. The diaphragm support member 80 is fixed by crimping the small diameter portion 30 of the outer cylinder member 14 radially inward. Thereby, the inside of the outer cylinder member 14 is hermetically sealed, and the liquid is sealed therein. In addition, as a liquid with which the inside of the outer cylinder member 14 is filled, ethylene glycol, water, etc. are used.

  A partition member 100 is provided inside the outer cylinder member 14. The partition member 100 is sandwiched between the diaphragm support member 80 and the throttle portion 32 of the outer cylinder member 14. A main liquid chamber 84 is formed between the partition member 100 and the elastic body 18, and a sub liquid chamber 86 is formed between the partition member 100 and the diaphragm 82. That is, the partition member 100 is provided between the main liquid chamber and the sub liquid chamber. The sub-liquid chamber 86 provided with the diaphragm 82 can be expanded and contracted according to the change in the hydraulic pressure.

(First embodiment)
FIG. 2 is an explanatory view of the partition member in the first embodiment, FIG. 2 (a) is a perspective view in a state of being divided in half, and FIG. 2 (b) is a side sectional view. As shown in FIG. 2B, the partition member 100 includes an orifice member 110, a membrane member 75, and a coil spring 140.

  The orifice member 110 is formed by combining an upper half portion 110a and a lower half portion 110b made of a resin material, an aluminum alloy, or the like. The orifice member 110 includes a ring-shaped bottom tube portion 111, a flange-shaped upper plate portion 112 extending radially outward from the upper end portion of the bottom tube portion 111, and a radially outer side from the lower end portion of the bottom tube portion 111. And a flange-like lower plate portion 113 that is extended to the bottom. Thereby, the orifice member 110 is formed with an orifice passage 114 having a U-shape in cross section that opens outward in the radial direction.

A part of the upper plate portion 112 in the circumferential direction is cut away to form an opening 118 on the main liquid chamber side of the orifice passage 114. A part of the lower plate 113 in the circumferential direction is cut off to form an opening (not shown) on the side of the secondary liquid chamber of the orifice passage 114. In addition, a partition wall (not shown) that blocks the orifice passage 114 in the circumferential direction is formed in the orifice passage 114 between the opening 118 on the main liquid chamber side and the opening on the sub liquid chamber side. Yes. Thus, the orifice passage 114 communicates the main liquid chamber and the sub liquid chamber.
In the engine mount 10 of the present embodiment, a shake orifice is formed by the orifice passage 114. The path length and cross-sectional area of the shake orifice, that is, the flow path resistance, is set (tuned) so as to correspond to a frequency (for example, 8 Hz to 12 Hz) of shake vibration that is resonance vibration in a low frequency range in the vehicle.

An upper support portion 117 of the membrane member 75 extends from the upper end portion of the bottom cylindrical portion 111 toward the inside in the radial direction. A lower support portion 116 of the membrane member 75 extends from the lower end portion of the bottom cylinder portion 111 toward the inside in the radial direction. A membrane member 75 formed in a film shape with an elastic material such as rubber is disposed between the upper support portion 117 and the lower support portion 116. The outer diameter of the membrane member 75 is smaller than the inner diameter of the bottom cylinder portion 111.
A ring member 76 made of a rigid material such as metal is embedded in the membrane member 75. The inner diameter of the ring member 76 is formed larger than the diameter of the through hole 115 formed at the center of the lower support portion 116. The ring member 76 can prevent the membrane member 75 from falling off the through hole 115.

  A coil spring 140 is disposed as an urging member between the upper support portion 117 of the orifice member 110 and the membrane member 75. The coil spring 140 is disposed in a compressed state, and the membrane member 75 is biased so as to close the through hole 115 of the lower support portion 116 from the main liquid chamber side toward the sub liquid chamber side. The coil spring 140 is formed so that when the pressure in the main liquid chamber becomes a predetermined value or less, the membrane member 75 is lifted so that the main liquid chamber and the sub liquid chamber can communicate with each other. Note that the spring constant of the coil spring 140 is set or the displacement of the membrane member 75 is restricted so that the communication between the main liquid chamber and the sub liquid chamber is ensured even when the pressure in the main liquid chamber becomes extremely small. It is desirable to provide means.

(Function)
Next, the operation of the engine mount having the above configuration will be described.
The membrane member 75 in a normal state is urged from the main liquid chamber toward the sub liquid chamber by the coil spring 140 and is pressed against the lower support portion 116 of the orifice member 110. At this time, the membrane member 75 made of a rubber material is sealed between the lower support portion 116 and the through-hole 115 is closed, so that the main liquid chamber and the sub liquid chamber do not communicate with each other.

  In this state, when shake vibration is input to the engine mount, the membrane member 75 is deformed according to the pressure difference between the main liquid chamber and the sub liquid chamber, and the liquid flows into the orifice passage 114 from the main liquid chamber. Since the orifice passage 114 is tuned so that liquid column resonance occurs at the frequency of the shake vibration, the engine mount can absorb and attenuate the shake vibration.

  Further, when idle vibration having a frequency higher than the shake vibration (for example, about 30 Hz) and a small amplitude is input to the engine mount, the orifice passage 114 is clogged and the liquid flows into the orifice passage 114 from the main liquid chamber. The pressure in the main liquid chamber rises. However, since the membrane member 75 is deformed according to the pressure difference between the main liquid chamber and the sub liquid chamber, it is possible to alleviate the pressure increase in the main liquid chamber. Therefore, it is possible to suppress an increase in the dynamic spring constant accompanying the pressure increase in the main liquid chamber, and it is possible to prevent idle vibration from being transmitted to the vehicle body.

FIG. 2C is an operation explanatory diagram when the pressure of the main liquid chamber becomes a predetermined value or less.
A load in the direction in which the liquid pressure in the main liquid chamber increases due to road surface irregularities (hereinafter referred to as “bound load”) is input, and then a load in the direction in which the liquid pressure in the main liquid chamber decreases (hereinafter referred to as “rebound load”). Is input, the negative pressure in the main liquid chamber is instantaneously increased (the pressure in the main liquid chamber is extremely small). In this embodiment, when the pressure in the main liquid chamber becomes a predetermined value or less, the membrane member 75 rises against the urging force of the coil spring 140. As a result, the communication path between the main liquid chamber and the sub liquid chamber is formed by the through hole 115 of the lower support part 116, the gap between the membrane member 75 and the orifice member 110, the gap of the coil spring 140, and the through hole of the upper support part 117. Is formed. Since the liquid flows from the sub liquid chamber into the main liquid chamber through this communication path, the negative pressure in the main liquid chamber can be eliminated. Therefore, the occurrence of cavitation can be prevented.

  As described above, the membrane member 75 of the present embodiment functions as a fixed membrane against shake vibration and idle vibration, and therefore can exhibit good vibration isolation performance. Further, since it functions as a valve body against a large vibration that generates cavitation, it is possible to prevent the occurrence of cavitation and accompanying noise.

As described in detail above, the engine mount according to the present embodiment includes the coil spring 140 that urges the membrane member 75 from the main liquid chamber toward the sub liquid chamber, and the coil spring 140 includes the main liquid chamber. The membrane member 75 is levitated when the pressure becomes less than a predetermined value so that the main liquid chamber and the sub liquid chamber can communicate with each other.
According to this configuration, when the pressure in the main liquid chamber becomes a predetermined value or less, it becomes possible to allow the liquid to flow from the sub liquid chamber into the main liquid chamber, thereby eliminating the negative pressure in the main liquid chamber. it can. In addition, since the membrane member 75 having a large outer diameter is used as the valve body, a large amount of liquid can be instantaneously introduced, and the negative pressure in the main liquid chamber can be quickly and reliably eliminated. . Therefore, the occurrence of cavitation can be prevented. Moreover, compared to the engine mount according to the prior art, it can be configured only by changing the shape of the orifice member 110 except for the addition of the coil spring 140, while suppressing an increase in manufacturing cost and a decrease in space efficiency, Occurrence of cavitation can be prevented.

The membrane member 75 is urged by the urging member so as to close the through hole 115 of the lower support portion 116, and includes a ring member 76 having a diameter larger than that of the through hole 115.
According to this configuration, even when the membrane member 75 is largely deformed, the ring member 76 does not pass through the through hole 115, so that the membrane member 75 can be prevented from falling off the through hole 115.

(Second Embodiment)
Next, an engine mount according to the second embodiment will be described.
FIG. 3 is an explanatory view of the partition member in the second embodiment, FIG. 3 (a) is a perspective view in a half-divided state, and FIG. 3 (b) is a side sectional view. In the first embodiment, a coil spring is employed as the biasing member. However, the second embodiment is different in that an elastic block is employed as the biasing member. Note that detailed description of portions having the same configuration as in the first embodiment is omitted.

Between the upper support portion 117 of the orifice member 110 and the membrane member 75, a plurality of elastic blocks 240 are disposed as urging members. The elastic block 240 is formed in an arc shape from an elastic material such as rubber, and is disposed along the outer periphery of the membrane member 75. Adjacent elastic blocks 240 are arranged with a gap therebetween. In the present embodiment, four arc-shaped elastic blocks 240 are formed integrally with the membrane member 75.
The elastic block 240 is disposed in a compressed state, and the membrane member 75 is urged from the main liquid chamber side toward the sub liquid chamber side. The elastic block 240 is formed so that when the pressure in the main liquid chamber becomes a predetermined value or less, the membrane member 75 is lifted so that the main liquid chamber and the sub liquid chamber can communicate with each other.

(Function)
Next, the operation of the engine mount having the above configuration will be described.
The membrane member 75 in the normal state is urged from the main liquid chamber toward the sub liquid chamber by the elastic block 240, and the through hole 115 of the lower support portion 116 is closed. As a result, the membrane member 75 functions as a fixed membrane against shake vibration and idle vibration, and therefore can exhibit good vibration isolation performance.

FIG. 3C is an operation explanatory diagram when the pressure of the main liquid chamber becomes a predetermined value or less.
In this embodiment, when the pressure in the main liquid chamber becomes a predetermined value or less, the membrane member 75 rises against the urging force of the elastic block 240. As a result, the through hole 115 of the lower support part 116, the gap between the membrane member 75 and the orifice member 110, the gap of the adjacent elastic block 240, and the through hole of the upper support part 117, the main liquid chamber and the sub liquid chamber are separated. A communication path is formed. Since the liquid flows from the sub liquid chamber into the main liquid chamber through this communication path, the negative pressure in the main liquid chamber can be eliminated. Therefore, the occurrence of cavitation can be prevented.

As described above, in the second embodiment, as compared with the engine mount according to the related art, it is possible to configure only the shape change of the orifice member 110 except for the addition of the elastic block 240, which increases the manufacturing cost and the space efficiency. It is possible to prevent the occurrence of cavitation while suppressing the decrease in the cavitation.
In the second embodiment, the membrane member 75 and the elastic block 240 are integrally formed. Thereby, it becomes possible to comprise substantially without an additional member, and the increase in manufacturing cost can be suppressed to the minimum.

It should be noted that the technical scope of the present invention is not limited to the above-described embodiments, and includes those in which various modifications are made to the above-described embodiments without departing from the spirit of the present invention. That is, the specific materials and configurations described in the embodiments are merely examples, and can be changed as appropriate.
For example, in the present embodiment, the engine mount in which the engine is fixed above the inner cylinder member has been described as an example, but on the contrary, the so-called suspension type engine in which the engine is fixed below the inner cylinder member. It is also possible to apply the present invention to the mount.

It is sectional drawing which shows the whole structure of the engine mount in embodiment. It is explanatory drawing of the partition member in 1st Embodiment. It is explanatory drawing of the partition member in 2nd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Engine mount (vibration isolator) 14 ... Outer cylinder member (1st attachment member) 16 ... Inner cylinder member (2nd attachment member) 18 ... Elastic body 75 ... Membrane member 76 ... Ring member 84 ... Main liquid chamber 86 ... Sub liquid chamber 100 ... partition member 114 ... orifice passage 115 ... through hole 140 ... coil spring (biasing member) 240 ... elastic block (biasing member)

Claims (3)

A first mounting member connected to either one of the vibration generating portion and the vibration receiving portion and formed in a substantially cylindrical shape;
A second mounting member connected to the other of the vibration generating unit and the vibration receiving unit and disposed on the inner peripheral side of the first mounting member;
An elastic body that elastically supports between the first mounting member and the second mounting member;
A main liquid chamber in which a part of the partition wall is made of the elastic body and the liquid is sealed;
A sub-liquid chamber in which a part of the partition wall is made of a diaphragm and a liquid is enclosed, and the internal volume can be expanded and contracted according to a change in the hydraulic pressure,
A partition member provided between the main liquid chamber and the sub liquid chamber;
An orifice passage communicating the main liquid chamber and the sub liquid chamber;
A vibration isolator comprising a membrane member that deforms according to a pressure difference between the main liquid chamber and the sub liquid chamber;
A biasing member that biases the membrane member from the main liquid chamber toward the sub liquid chamber;
The urging member is formed to displace the membrane member so that the main liquid chamber and the sub liquid chamber can communicate with each other when the pressure of the main liquid chamber becomes a predetermined value or less. An anti-vibration device characterized by that. The membrane member is urged by the urging member so as to close a through hole formed in the partition member,
The vibration isolator according to claim 1, wherein the membrane member includes a ring member having a diameter larger than that of the through hole.   The vibration isolator according to claim 1 or 2, wherein the urging member is formed integrally with the membrane member.

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