JP6984947B2 - Anti-vibration device - Google Patents

Description

The present invention relates to a vibration isolator in which a liquid is enclosed.

As a vibration isolator, a liquid-filled type vibration isolator equipped with a movable member that displaces between the main liquid chamber and the sub liquid chamber according to the pressure difference between the main liquid chamber and the sub liquid chamber is known. (See, for example, Patent Document 1.).

For example, in the liquid-filled anti-vibration device of Patent Document 1, when vibration or the like is input, the anti-vibration effect is exhibited based on the hydraulic pressure absorption effect of the main liquid chamber due to the elastic deformation of the movable member.

By the way, in the liquid-filled anti-vibration device, for example, when an automobile gets over a step or runs on a road surface with large unevenness and a large load is input, cavitation occurs in the main liquid chamber, causing abnormal noise and vibration. It may occur.

However, in the vibration isolator of Patent Document 1, a relief valve is provided between the main liquid chamber and the auxiliary liquid chamber, and the relief valve is opened when a negative pressure exceeding a certain level is generated in the main liquid chamber. It is configured so that the pressures of the main liquid chamber and the sub liquid chamber move toward the equilibrium state and the occurrence of cavitation is suppressed.

Japanese Unexamined Patent Publication No. 2009-8513

With the relief valve of the conventional anti-vibration device, when an excessive negative pressure is input to the main liquid chamber, it may be difficult to open and it may be difficult to suppress the occurrence of cavitation, and there is room for improvement.

In consideration of the above facts, an object of the present invention is to provide a vibration isolator capable of suppressing the occurrence of cavitation when an excessive load is input.

The vibration isolator according to claim 1 is connected to a first mounting member connected to either one of a vibration generating portion and a vibration receiving portion, and to any one of the vibration generating portion and the vibration receiving portion. A second mounting member, an elastic body that elastically connects the first mounting member and the second mounting member, and a main liquid provided on the first mounting member and having the elastic body as a part of a wall surface. A partition member for partitioning a chamber and a sub-liquid chamber, which is provided inside the partition member, communicates with the main liquid chamber through a first communication hole, and communicates with the sub-liquid chamber through a second communication hole. A movable member made of an elastic body that is accommodated in the accommodating chamber and is displaced between the main liquid chamber side and the sub-liquid chamber side according to the pressure difference between the main liquid chamber and the sub-liquid chamber. , A through hole formed at a position corresponding to the first communication hole of the movable member and penetrating from the main liquid chamber side to the sub liquid chamber side, and a through hole provided along the peripheral edge of the through hole of the movable member. A convex portion on the main liquid chamber side that protrudes toward the liquid chamber and curves in a direction away from the through hole, and the tip of which contacts the inner wall of the accommodation chamber, and the entire circumference of the peripheral edge of the through hole of the movable member. The sub-liquid chamber side convex portion is provided so as to project toward the sub-liquid chamber and abut on the inner wall of the accommodating chamber to close between the through hole and the second communication hole.

In the vibration isolator according to claim 1, when a shocking load is input and an excessive negative pressure is generated in the main liquid chamber, the pressure of the liquid on the secondary liquid chamber side is relatively higher than that of the liquid on the main liquid chamber side. Since the pressure is higher than the pressure, the liquid on the secondary liquid chamber side presses the movable member from the second communication hole, the movable member is displaced toward the main liquid chamber side, and the convex portion on the secondary liquid chamber side is from the inner wall of the accommodation chamber. The second communication hole is opened at a distance. Further, when the movable member is displaced, the convex portion on the main liquid chamber side provided on the movable member is pressed toward the inner wall side of the accommodation chamber and elastically deforms.

As a result, the liquid in the auxiliary liquid chamber flows from the second communication hole into the main liquid chamber through the accommodation chamber and the first communication hole, and the pressure of the liquid in the main liquid chamber and the pressure of the liquid in the auxiliary liquid chamber are in an equilibrium state. On the other hand, the excessive negative pressure in the main liquid chamber is eliminated.
As a result, the pressure of the liquid in the main liquid chamber is prevented from reaching the negative pressure that causes cavitation, and abnormal noise and vibration caused by cavitation are suppressed.

Further, in the anti-vibration device of claim 1, the convex portion on the main liquid chamber side is curved in a direction away from the through hole, and the tip is in contact with the inner wall of the accommodation chamber, so that the movable member is on the main liquid chamber side. When displaced toward, the curved main liquid chamber side convex portion is bent and deformed so that the tip of the convex portion is in contact with the inner wall of the accommodating chamber and collapses as a whole.

Since the convex portion on the main liquid chamber side bends and deforms so as to collapse, the linear region tends to expand as a spring characteristic. That is, since the spring constant of the convex portion on the main liquid chamber side is suppressed from suddenly increasing in the middle, the movable member is easily displaced, and as a result, the space between the through hole and the second communication hole is easily opened. .. In other words, the movable member that was blocking the space between the through hole and the second communication hole can be easily separated from the inner wall of the accommodation chamber, so that the pressure in the main liquid chamber and the pressure in the auxiliary liquid chamber quickly move to an equilibrium state. It can be changed, and the effect of suppressing the occurrence of cavitation can be enhanced as compared with the conventional case.

According to the second aspect of the present invention, in the vibration isolator according to the first aspect, the movable member is formed with a notch that divides the main liquid chamber side convex portion into a plurality of portions in the circumferential direction of the through hole. There is.

When the main liquid chamber side convex portion protruding toward the main liquid chamber and curved in the direction away from the through hole is continuous along the peripheral edge of the through hole, the main liquid chamber side convex portion presses against the inner wall of the accommodation chamber. As a result, tension is generated in the circumferential direction on the tip side of the convex portion on the main liquid chamber side, and this tension acts to suppress the deformation of the through hole on the convex portion on the main liquid chamber side in the radial direction. It ends up.

Therefore, by dividing the main liquid chamber side convex portion into a plurality of pieces in the circumferential direction of the through hole by a notch, the circumferential length of the main liquid chamber side convex portion is shortened and the circumferential direction generated in the main liquid chamber side convex portion is shortened. Tension can be reduced. As a result, each of the main liquid chamber side convex portions is easily bent and deformed radially outward, and the movable member is more easily displaced, so that the second communication hole is more easily opened.

As described above, the vibration isolator of the present invention has an excellent effect of suppressing the occurrence of cavitation when an excessive load is input.

It is sectional drawing which shows the vibration isolation device which concerns on one Embodiment of this invention. It is a perspective view which shows the anti-vibration device attached to a bracket. It is sectional drawing which shows the vibration isolation device attached to the bracket. (A) is a cross-sectional view of a partition member showing a member in a normal state, and (B) is a cross-sectional view of a partition member showing a state in which the cylindrical portion of the member is displaced. It is a perspective view which shows the membrane and the membrane mounting member.

An embodiment of the vibration isolator according to the present invention will be described with reference to FIGS. 1 to 5.
As shown in FIG. 1, the vibration isolator 10 includes a metal cylinder 12 connected to the vehicle body side as an example of a vibration receiving portion. A rubber elastic body 14 is vulcanized and bonded to the upper part of the inner circumference of the tubular body 12, and the tubular body 12 as an example of the first mounting member has an opening on the upper side closed by the elastic body 14. ing.

As shown in FIGS. 2 and 3, the tubular body 12 is inserted into the tubular portion 18 of the bracket 16 connected to the vehicle body. The bracket 16 is provided with a leg portion 20 used for connecting to the vehicle body.

As shown in FIG. 1, a support 22 connected to the engine side as an example of a vibration generating portion is embedded in the upper center of the elastic body 14, and as an example of a second mounting member in the elastic body 14. Support 22 is vulcanized and bonded. An engine mounting member 24 extending in the horizontal direction is arranged on the upper portion of the support body 22, and a bolt 28 penetrating the hole 26 of the engine mounting member 24 is screwed into a female screw 30 formed in the support body 22. As a result, the engine mounting member 24 is fixed to the support 22. As a result, when vibration is input from the engine, the elastic body 14 is elastically deformed, and the support 22 and the tubular body 12 move relative to each other.

As shown in FIG. 3, a stopper portion 31 made of an elastic body is attached to the engine mounting member 24. When the support 22 is excessively displaced, the stopper portion 31 comes into contact with the frame portion 32 of the bracket 16 to suppress the excessive displacement of the support 22.

As shown in FIG. 1, a partition member 33 is arranged inside the tubular body 12 under the elastic body 14. As shown in FIG. 4, the partition member 33 includes a partition member main body 34 and a membrane mounting member 38. As shown in FIG. 1, a main liquid chamber 40 filled with a liquid such as ethylene glycol is formed between the partition member main body 34 and the elastic body 14.

A diaphragm 42 is arranged under the member mounting member 38. A metal annular fixing member 46 is embedded in the outer peripheral portion of the diaphragm 42, and a part of the outer peripheral portion of the partition member main body 34 and the outer peripheral portion of the diaphragm 42 are crimped and fixed to the tubular body 12. An auxiliary liquid chamber 44 filled with a liquid such as ethylene glycol is formed between the membrane mounting member 38 and the diaphragm 42.

As shown in FIG. 4A, a downward first concave portion 48 which is circular when viewed from the lower surface side is formed in the central portion on the lower surface of the partition member main body 34, and the downward outer side of the downward first concave portion 48 in the radial direction. A downward second recess 50 having an annular shape when viewed from the lower surface side is formed, and an annular shape is formed between the downward first recess 48 and the downward second recess 50 when viewed from the lower surface side. The downward annular convex portion 52 is formed. A sheet-shaped upper rubber wall 54 having an annular shape is adhered to the downward second recess 50.

The member mounting member 38 is formed by forming a metal plate in a disk shape, and is fixed in close contact with the lower surface of the partition member main body 34. At the center of the member mounting member 38, an upward recess 56 having a substantially same outer diameter as the outer diameter of the downward second recess 50 of the partition member main body 34 and having a circular shape when viewed from above is formed. A circular lower rubber wall 58 is adhered to the upward recess 56.

On the lower rubber wall 58, an upward annular convex portion 60 having an annular shape when viewed from the upper surface side is formed at a position facing the downward annular convex portion 52 of the partition member main body 34, and the upward annular convex portion is formed. The inside of the 60 is the upward first concave portion 62, and the outside of the upward annular convex portion 60 is the upward second concave portion 64.

Here, between the partition member main body 34 and the membrane mounting member 38, a first storage chamber 66 is formed between the downward first recess 48 of the partition member main body 34 and the upward first recess 62 of the membrane mounting member 38. A second storage chamber 68 is formed between the downward second recess 50 of the partition member main body 34 and the upward second recess 64 of the membrane mounting member 38.

A membrane 36 as an example of a movable member formed in a disk shape by an elastic body such as rubber is arranged between the partition member main body 34 and the membrane mounting member 38.
The central portion of the membrane 36 is a cylindrical portion 70 formed to be the thickest in the membrane 36, and a through hole 72 is formed in the center of the cylindrical portion 70. The membrane 36 is provided with a holding portion 74 formed to have a constant thickness on the radial outer side of the cylindrical portion 70, and a displacement portion 76 is provided on the radial outer side of the holding portion 74. The cylindrical portion 70 and the displacement portion 76 are elastically supported by the holding portion 74 so as to be displaced according to the pressure difference between the main liquid chamber 40 and the auxiliary liquid chamber 44.

As shown in FIGS. 4A and 5, a plurality of main liquid chamber side convex portions 78 are integrally formed with the cylindrical portion 70 on the upper surface of the cylindrical portion 70 around the through hole 72. .. The main liquid chamber side convex portion 78 is arranged in the circumferential direction through a notch 80 extending in the radial direction from the cylindrical portion 70 toward the tip end. The convex portion 78 on the main liquid chamber side is curved in a direction away from the through hole 72 in a side view. The main liquid chamber side convex portion 78 is, in other words, a curved convex portion.

As shown in FIGS. 4A and 5, a plurality of annular protrusions 84 having different diameters are formed on both sides of the displacement portion 76 at intervals from the inside in the radial direction to the outside in the radial direction.

As shown in FIG. 4A, the membrane 36 is sandwiched between the downward annular protrusion 52 of the partition member main body 34 and the upward annular protrusion 60 formed on the lower rubber wall 58 of the membrane mounting member 38. The portion 74 is sandwiched and fixed.

With the membrane 36 fixed in this way, the displacement portion 76 of the membrane 36 is housed inside the second storage chamber 68 so as to be vertically displaceable. In other words, the displacement portion 76 of the membrane 36 has the second accommodating chamber 68 so that a gap is formed between the lower rubber wall 58 of the membrane mounting member 38 and the upper rubber wall 54 of the partition member main body 34. It is housed inside.

Further, with the membrane 36 fixed in this way, the cylindrical portion 70 of the membrane 36 is housed inside the first storage chamber 66. The tip of the main liquid chamber side convex portion 78 formed on the upper surface of the cylindrical portion 70 is in contact with the bottom surface of the downward first concave portion 48 of the partition member main body 34, and the bottom surface of the cylindrical portion 70 is a rubber mounting member. It is in contact with the bottom surface of the upward first recess 62 formed in the lower rubber wall 58 of 38.

Here, a groove 85 extending in the circumferential direction is formed on the outer peripheral surface of the partition member main body 34, and as shown in FIG. 1, the groove 85 is closed by the tubular body 12 to form an orifice passage 86. is doing. One end of the orifice passage 86 communicates with the main liquid chamber 40 via a first hole 88 formed in the partition member main body 34, and the other end side is a second hole 90 formed in the partition member main body 34. And, it communicates with the auxiliary liquid chamber 44 through the hole 92 formed in the membrane mounting member 38. Therefore, the main liquid chamber 40 and the sub liquid chamber 44 are always in communication with each other via the orifice passage 86.

As shown in FIGS. 1 and 4A, a hole 93 as an example of the first communication hole is formed in the center of the partition member main body 34, and the main liquid chamber 40 is formed through the hole 93. It is always in communication with the first accommodation room 66. In the membrane mounting member 38 and the lower rubber wall 58, a hole 94 as an example of a plurality of second communication holes communicating with the auxiliary liquid chamber 44 is provided along the circumferential direction at a position facing the cylindrical portion 70 of the membrane 36. Is formed. In the normal state (state shown in FIG. 4A), the space between the through hole 72 and the hole 94 is closed by the lower surface of the cylindrical portion 70 in contact with the lower rubber wall 58. In the cylindrical portion 70 of the membrane 36, the portion protruding below the lower surface of the holding portion 74 is referred to as the auxiliary liquid chamber side convex portion 70A. In other words, the sub-liquid chamber side convex portion 70A is an annular convex portion that is formed in an annular shape and projects downward from the lower surface of the holding portion 74.

Further, a plurality of holes 96 communicating the main liquid chamber 40 and the second accommodating chamber 68 are formed in the partition member main body 34 and the upper rubber wall 54 along the circumferential direction. Further, a plurality of holes 98 that communicate the second accommodating chamber 68 and the auxiliary liquid chamber 44 are formed in the membrane mounting member 38 and the lower rubber wall 58 along the circumferential direction. Therefore, the main liquid chamber 40 and the sub liquid chamber 44 are always in communication with each other through the hole 96, the second storage chamber 68, and the hole 98.

(Action, effect)
The vibration isolator 10 of the present embodiment is attached to the bracket 16, the legs 20 of the bracket 16 are attached to the vehicle body, and the engine is attached to the engine mounting member 24 for use.
When the vibration of the engine is input to the vibration isolator 10, the vibration is absorbed by the resistance based on the internal friction of the elastic body 14, and the elastic body 14 is deformed to expand and contract the main liquid chamber 40. When the liquid of 40 and the liquid of the auxiliary liquid chamber 44 move back and forth through the orifice passage 86, they are absorbed by the passage resistance of the liquid flowing through the orifice passage 86 or the liquid column resonance.

When the frequency of vibration rises and the orifice passage 86 becomes clogged, the membrane 36 is displaced inside the second accommodating chamber 68 according to the vibration due to the pressure fluctuation of the main liquid chamber 40, and the pressure of the main liquid chamber 40 is increased. The rise is suppressed, and the rise of the dynamic spring constant of the vibration isolator 10 is suppressed. This makes it possible to reduce the transmission of vibration even if the frequency of vibration rises.

(Impact load input)
By the way, when an automobile gets over a step or travels on a road surface with large unevenness, a shocking load is input to the vibration isolator 10, and the support 22 is suddenly displaced upward, an abnormal noise is generated in the main liquid chamber 40. Excessive negative pressure that causes cavitation that causes vibration may occur.

An excessive negative pressure is generated in the main liquid chamber 40, in other words, when the pressure in the main liquid chamber 40 is excessively reduced, the pressure in the auxiliary liquid chamber 44 becomes relatively larger than the pressure in the main liquid chamber 40. The liquid in the auxiliary liquid chamber 44 pushes up the cylindrical portion 70 of the membrane 36 through the holes 94 formed in the membrane mounting member 38 and the lower rubber wall 58, and the bottom surface of the cylindrical portion 70 is the lower side of the membrane mounting member 38. A gap is formed between the bottom surface of the cylindrical portion 70 and the lower rubber wall 58 apart from the rubber wall 58, and the through hole 72 and the hole 94 communicate with each other, so that the liquid in the auxiliary liquid chamber 44 can be stored in the first storage chamber. It flows into the main liquid chamber 40 through 66 and the hole 93. As a result, the pressure in the main liquid chamber 40 and the pressure in the auxiliary liquid chamber 44 move toward an equilibrium state, and the excessive negative pressure state in the main liquid chamber 40 is eliminated, so that cavitation that causes abnormal noise and vibration occurs. Is suppressed.

Here, in the vibration isolator 10 of the present embodiment, the main liquid chamber side convex portion 78 formed on the upper portion of the cylindrical portion 70 by pushing up the cylindrical portion 70 of the membrane 36 is shown in FIG. 4 (A). As shown in FIG. 4B from the state, the tip of the first recess 48 is elastically deformed so as to bend as a whole while sliding downward on the bottom surface of the first recess 48 in the radial direction.

By the way, as an example, when an elastic body such as rubber formed in a columnar shape is compressively deformed, the spring constant tends to increase as it is compressed, and the spring characteristic becomes non-linear. Therefore, if a cylindrical main liquid chamber side convex portion is formed on the upper portion of the cylindrical portion 70, even if the cylindrical portion 70 is largely separated from the lower rubber wall 58 by the pressure of the auxiliary liquid chamber 44, the spring constant It is difficult to greatly compress the columnar convex portion on the main liquid chamber side. Therefore, the cylindrical portion 70 is largely separated from the lower rubber wall 58 to widen the hole 94, and it becomes difficult for a large amount of liquid to flow from the auxiliary liquid chamber 44 into the main liquid chamber 40.

In other words, when a cylindrical main liquid chamber side convex portion is formed on the upper part of the cylindrical portion 70, even if the cylindrical portion 70 is largely displaced to open the hole 94 widely, the cylindrical main liquid chamber side convex portion is formed. As the pressure increases, the compression reaction force (the force of the cylindrical portion 70 toward the side opposite to the main liquid chamber 40 side) increases, so that the hole 94 becomes difficult to open, and a large amount of liquid is discharged from the auxiliary liquid chamber 44 to the main liquid. It becomes difficult to flow into the room 40.

On the other hand, as in the present embodiment, the convex portion 78 on the main liquid chamber side has a curved cross-sectional shape and is elastically deformed so as to bend. Therefore, when an elastic body such as rubber formed in a columnar shape is compressionally deformed. By comparison, the spring characteristics can be made closer to linear. Therefore, in the membrane 36 of the present embodiment, the cylindrical portion 70 is easily displaced, the cylindrical portion 70 is largely separated from the lower rubber wall 58, and a large amount of liquid flows from the auxiliary liquid chamber 44 into the main liquid chamber 40. It becomes possible. Therefore, the effect of suppressing the occurrence of cavitation when an excessive negative pressure is generated in the main liquid chamber 40 is high.

Further, since the main liquid chamber side convex portion 78 of the present embodiment is not continuously formed in the circumferential direction and is divided into a plurality of parts by the notch 80, when the main liquid chamber side convex portion 78 is bent and deformed. The tension in the circumferential direction generated in the can be reduced. As a result, each of the main liquid chamber side convex portions 78 is more likely to be bent and deformed radially outward as compared with the case where they are not divided. Therefore, the membrane 36 is more easily displaced and the holes 94 are more easily opened as compared with the case where the main liquid chamber side convex portion 78 is not divided.

On the other hand, when the excessive negative pressure of the main liquid chamber 40 is eliminated and the cylindrical portion 70 pushed by the main liquid chamber side convex portion 78 moves downward, as shown in FIG. 4A, the bottom surface of the cylindrical portion 70 However, it comes into contact with the upward first recess 62 of the lower rubber wall 58, and the space between the through hole 72 and the hole 94 is closed. Here, since the lower rubber wall 58 with which the cylindrical portion 70 contacts is formed of an elastic body such as rubber, it is possible to suppress the generation of tapping sound when the cylindrical portion 70 contacts the lower rubber wall 58. Can be done.

[Other embodiments]
Although the embodiment of the anti-vibration device of the present invention has been described above, the present invention is not limited to the above, and can be variously modified and implemented without departing from the gist thereof. Of course there is.

10 ... Anti-vibration device, 12 ... Cylindrical body (first mounting member), 14 ... Elastic body, 22 ... Support (second mounting member), 33 ... Partition member, 36 ... Membrane (movable member), 40 ... Main liquid Room, 44 ... Secondary liquid chamber, 66 ... First storage chamber (containment chamber), 70 ... Cylindrical portion (secondary liquid chamber side convex portion), 70A ... Secondary liquid chamber side convex portion, 72 ... Through hole, 78 ... Main liquid Room side convex part, 93 ... hole (first communication hole), 94 ... hole (second communication hole), 80 ... notch

Claims (2)

The first mounting member connected to either the vibration generating part or the vibration receiving part, and
A second mounting member connected to either one of the vibration generating part and the vibration receiving part, and
An elastic body that elastically connects the first mounting member and the second mounting member,
A partition member provided on the first mounting member and partitioning a main liquid chamber and a sub liquid chamber having the elastic body as a part of a wall surface.
A storage chamber provided inside the partition member, communicating with the main liquid chamber through the first communication hole, and communicating with the sub liquid chamber through the second communication hole.
A movable member housed in the storage chamber and made of an elastic body that is displaced between the main liquid chamber side and the sub liquid chamber side according to the pressure difference between the main liquid chamber and the sub liquid chamber.
A through hole formed at a position corresponding to the first communication hole of the movable member and penetrating from the main liquid chamber side to the sub liquid chamber side,
It is provided along the peripheral edge of the through hole of the movable member, protrudes toward the main liquid chamber and curves in a direction away from the through hole, and the tip of the movable member is convex toward the main liquid chamber in contact with the inner wall of the accommodation chamber. Department and
The movable member is provided over the entire circumference of the peripheral edge of the through hole, projects toward the auxiliary liquid chamber, and abuts on the inner wall of the accommodation chamber to be between the through hole and the second communication hole. And the convex part on the side of the auxiliary liquid chamber that closes the
Anti-vibration device with. The vibration isolator according to claim 1, wherein the movable member is formed with a notch that divides the convex portion on the main liquid chamber side into a plurality of portions in the circumferential direction of the through hole.

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