JP7015165B2 - Anti-vibration device - Google Patents

Description

The present invention relates to a vibration isolator that is applied to, for example, an automobile, an industrial machine, or the like, and attenuates and absorbs vibration of a vibration generating portion of an engine or the like.

Conventionally, a tubular first mounting member connected to either one of a vibration generating portion and a vibration receiving portion, and a second mounting member connected to the other, and both mounting members are elastically connected. It is provided with an elastic body and a partition member for partitioning the liquid chamber in the first mounting member in which the liquid is sealed into the first liquid chamber and the second liquid chamber, and the partition member includes the first liquid chamber and the second liquid chamber. A vibration isolator is known in which a restricted passage communicating with a liquid chamber and a storage chamber communicating with a first liquid chamber and a second liquid chamber are formed as well as accommodating a membrane.
As a vibration isolator of this type, for example, as shown in Patent Document 1 below, a configuration is known in which a support portion for supporting the outer peripheral edge portion of the membrane from both sides in the thickness direction is arranged in a storage chamber. ..
In this vibration isolator, since the outer peripheral edge of the membrane is supported by the support portion, the deformation of the membrane is suppressed at the time of vibration input, and it becomes possible to suppress the membrane from colliding with the wall surface of the accommodation chamber. It is possible to suppress the generation of tapping sound.

Japanese Unexamined Patent Publication No. 2014-181803

However, in the conventional vibration isolator, since the deformation of the membrane is suppressed at the time of vibration input, there is a problem that it is difficult to keep the spring at the time of input of idle vibration having a relatively small amplitude and a relatively high frequency. there were.
This problem becomes apparent when the corners that are pointed outward in the plan view are formed on the membrane, because the corners are less likely to be deformed at the time of vibration input.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vibration isolator capable of suppressing the generation of tapping sound while keeping the spring at the time of inputting idle vibration low.

In order to solve the above problems, the present invention proposes the following means.
The vibration isolator according to the present invention includes a tubular first mounting member connected to either one of a vibration generating portion and a vibration receiving portion, a second mounting member connected to the other, and both mounting members. The partition member is provided with an elastic body for elastically connecting the liquids and a partition member for partitioning the liquid chamber in the first mounting member in which the liquid is sealed into the first liquid chamber and the second liquid chamber. , A liquid in which a restricted passage connecting the first liquid chamber and the second liquid chamber and a storage chamber communicating with the first liquid chamber and the second liquid chamber while accommodating the membrane are formed. An enclosed anti-vibration device, the accommodation chamber is provided with support portions that support the outer peripheral edge portion of the membrane from both sides in the thickness direction, and the membrane is centered on the first mounting member. A corner portion that is sharp toward the outside is formed in a plan view from the axial direction along the axis, and in the membrane, at least the portion of the outer peripheral edge portion located at the corner portion is formed from the inside of the outer peripheral edge portion. A stretchable portion that can be expanded and contracted is formed in the connecting portion, and the restricted passage has a first communication portion that opens to the first liquid chamber, a second communication portion that opens to the second liquid chamber, and the first communication portion. The main body flow path for communicating the portion and the second communication portion is provided, and the main body flow path is the first mounting member from the communication portion of either the first communication portion or the second communication portion. A main flow path that extends toward one side in the circumferential direction along the central axis of the main flow path, and a main flow path that protrudes inward in the radial direction from one end of the peripheral direction in the main flow path and is from the one communication portion side. It is provided with a vortex chamber that forms a swirling flow of the liquid according to the flow velocity of the liquid flowing in through the external communication portion , and the vortex chamber has a circular shape when viewed from the axial direction along the central axis and is axially oriented. The liquid is arranged side by side with the accommodation chamber in an orthogonal direction, and the outer communication portion extends in the tangential direction of the inner peripheral surface of the vortex chamber in the plan view and flows into the vortex chamber from the outer communication portion. Is rectified in the tangential direction through the external communication portion, and then swivels by flowing along the inner peripheral surface of the vortex chamber, and the membrane and the accommodation chamber are viewed from the axial direction. The membrane and the containment chamber are formed in the same shape and the same size in a plan view, and the membrane and the accommodation chamber have a crescent shape in a plan view seen from the axial direction, and the two corners of the crescent shape are connected to each other. It is characterized in that at least a part of the vortex chamber is located between them.

According to the present invention, at the time of vibration input, both mounting members are relatively displaced while elastically deforming the elastic body, the hydraulic pressures of the first liquid chamber and the second liquid chamber fluctuate, and the liquid passes through the limiting passage. Attempts to circulate between the first liquid chamber and the second liquid chamber. At this time, the liquid flows into the restricted passage through one of the first communication portion and the second communication portion, passes through the main body flow path, and then passes through the other of the first communication portion and the second communication portion. Outflow from.
Further, since the outer peripheral edge portion of the membrane is supported from both sides in the thickness direction by the support portion, the deformation of the membrane is suppressed at the time of vibration input, and the membrane can be prevented from colliding with the wall surface of the accommodation chamber. This makes it possible to suppress the generation of tapping sound.
Further, in the membrane, a stretchable portion that can be stretched and deformed is formed in a portion that is continuous from the inside of the outer peripheral edge portion with respect to a portion located at least at a corner portion of the outer peripheral edge portion. Therefore, in combination with the fact that the outer peripheral edge portion of the membrane is supported by the support portion, the expansion and contraction portion at the time of vibration input is performed even though the corner portion of the membrane is particularly difficult to be deformed at the time of vibration input. By expanding and contracting, the corners of the membrane can be smoothly deformed by following the input vibration. As a result, even if idle vibration is input, it is possible to secure the amount of deformation of the membrane, and it is possible to keep the spring at the time of input of idle vibration low.
From the above, it is possible to suppress the generation of tapping sound while keeping the spring at the time of input of idle vibration low.
Since the main body flow path is provided with a vortex chamber, when a large load (vibration) is input to the vibration isolator, the liquid flows into the vortex chamber from one of the first communication portion and the second communication portion. When the flow velocity of the liquid is sufficiently high and a swirling flow of the liquid is formed in the vortex chamber, for example, the energy loss due to the formation of this swirling flow and the space between the liquid and the inner surface of the vortex chamber are generated. The pressure loss of the liquid can be increased due to the energy loss due to the friction of the liquid. As a result, the flow rate of the liquid that passes through the other of the first communication section and the second communication section and flows into the first liquid chamber or the second liquid chamber can be suppressed. Therefore, even if a large load (vibration) is input to the vibration isolator, the liquid that has passed through the other of the first communication section and the second communication section and has flowed into the first liquid chamber or the second liquid chamber. It is possible to suppress the difference in flow velocity between the liquid in the first liquid chamber or the liquid in the second liquid chamber to a small value, and to suppress the generation of vortices due to the difference in flow velocity and the generation of bubbles due to this vortex. Can be done.
From the above, it is possible to suppress the generation of abnormal noise caused by cavitation collapse in which bubbles collapse.
Moreover, since the membrane and the containment chamber have a crescent shape in a plan view from the axial direction, and at least a part of the vortex chamber is located between the two corners of the crescent shape, the containment chamber. And even though the vortex chambers are arranged side by side in the direction orthogonal to the axial direction, a wide flat area of the membrane can be secured. Therefore, even though the outer peripheral edge of the membrane is supported by the support and the membrane has corners, which makes it difficult for the membrane to deform, the membrane is smoothly deformed when idle vibration is input. Can be made easier.

Here, the stretchable portion may be bent in the thickness direction of the membrane.
In this case, since the stretchable portion is bent in the thickness direction of the membrane, it is possible to reliably secure the stretchable deformation amount while suppressing the decrease in durability.

Further, the telescopic portion may be provided with a pointed top toward the wall surface defining the accommodation chamber, and a relief recess may be formed in a portion of the wall surface defining the accommodation chamber facing the top.

In this case, since a relief recess is formed in the accommodation chamber, when the expansion / contraction portion is expanded / contracted and deformed due to the input of vibration, the top of the expansion / contraction portion that easily collides with the wall surface defining the accommodation chamber is the escape recess. It becomes possible to enter into the stretched portion, and the stretchable portion can be smoothly stretched and deformed.

Further, the expansion / contraction portion may be continuously arranged along the outer peripheral edge portion of the membrane over the entire circumference thereof.
In this case, since the telescopic portion is continuously arranged along the outer peripheral edge portion of the membrane over the entire circumference thereof, the spring at the time of inputting the idle vibration can be surely suppressed to a low level.

Further, when any one of the first communication part and the second communication part has a plurality of pores penetrating the barrier facing the first liquid chamber or the second liquid chamber, the liquid has a plurality of fine particles. When flowing into the first liquid chamber or the second liquid chamber from the restricted passage through the holes, the first liquid chamber or the second liquid chamber or the second liquid chamber is circulated while being pressure-lossed by the barrier formed by these pores. The flow velocity of the liquid flowing into the liquid chamber can be suppressed. Moreover, since the liquid flows through a plurality of pores instead of a single pore, the liquid can be branched and circulated in a plurality of pores, and the flow velocity of the liquid passing through the individual pores can be reduced. Can be done.
Since these effects are exerted on the liquid whose pressure is lost by the vortex chamber, it is possible to surely suppress the generation of bubbles in the first liquid chamber or the second liquid chamber.
Further, even if bubbles are generated in the restricted passage instead of the first liquid chamber or the second liquid chamber, the generated bubbles are transferred to each other in the first liquid chamber or the second liquid chamber by passing the liquid through a plurality of pores. It becomes possible to separate the bubbles in the liquid chamber, and it is possible to suppress the merging and growth of bubbles and facilitate the maintenance of the bubbles in a finely dispersed state.
As described above, it is possible to suppress the generation of bubbles themselves, and even if bubbles are generated, it is possible to easily maintain the state in which the bubbles are finely dispersed, so that even if cavitation collapse occurs, it will occur. Abnormal noise can be suppressed to a small level.

According to the present invention, it is possible to suppress the generation of tapping sound while keeping the spring at the time of inputting idle vibration low.

It is a vertical sectional view of the vibration isolation device which concerns on one Embodiment of this invention. It is a top view of the partition member constituting the vibration isolation device shown in FIG. 1. It is an enlarged vertical sectional view of the partition member shown in FIGS. 1 and 2.

Hereinafter, embodiments of the vibration isolator according to the present invention will be described with reference to FIGS. 1 to 3.
As shown in FIG. 1, the vibration isolator 10 is attached to a tubular first mounting member 11 connected to either one of a vibration generating portion and a vibration receiving portion, and to either one of the vibration generating portion and the vibration receiving portion. The second mounting member 12 to be connected, the elastic body 13 elastically connecting the first mounting member 11 and the second mounting member 12 to each other, and the liquid chamber 19 in the first mounting member 11 will be described later as a main liquid chamber (a main liquid chamber described later). It is a liquid-filled type anti-vibration device including a partition member 16 for partitioning a first liquid chamber) 14 and a secondary liquid chamber (second liquid chamber) 15.

Hereinafter, the direction along the central axis O of the first mounting member 11 is referred to as an axial direction. Further, the second mounting member 12 side along the axial direction is referred to as an upper side, and the partition member 16 side is referred to as a lower side. Further, in a plan view of the vibration isolator 10 from the axial direction, the direction that intersects the central axis O is referred to as the radial direction, and the direction that orbits around the central axis O is referred to as the circumferential direction.
The first mounting member 11, the second mounting member 12, and the elastic body 13 are each formed in a circular shape or an annular shape in a plan view, and are arranged coaxially with the central axis O.

When the vibration isolator 10 is mounted on an automobile, for example, the second mounting member 12 is connected to the engine as a vibration generating portion, and the first mounting member 11 is connected to the vehicle body as a vibration receiving portion. As a result, the vibration of the engine is suppressed from being transmitted to the vehicle body. The first mounting member 11 may be connected to the vibration generating portion, and the second mounting member 12 may be connected to the vibration receiving portion.

The second mounting member 12 is a columnar member extending in the axial direction, and is formed in a hemispherical shape in which the lower end portion bulges downward. In the second mounting member 12, a flange portion 12a protruding outward in the radial direction is formed in a portion located above the lower end portion of the hemispherical shape. A screw hole 12b extending downward from the upper end surface thereof is bored in the second mounting member 12, and a bolt (not shown) serving as a mounting tool on the engine side is screwed into the screw hole 12b. The second mounting member 12 is arranged at the upper end opening of the first mounting member 11 via the elastic body 13.

The elastic body 13 is a rubber body that is vulcanized and adhered to the upper end opening of the first mounting member 11 and the outer peripheral surface of the lower portion of the second mounting member 12, respectively, and is interposed between them. The upper end opening of the mounting member 11 is closed from above. A first rubber film 13a that integrally covers the lower surface, the outer peripheral surface, and the upper surface of the flange portion 12a is integrally formed on the upper end portion of the elastic body 13. A second rubber film 13b that tightly covers the inner peripheral surface of the first mounting member 11 is integrally formed at the lower end portion of the elastic body 13. As the elastic body 13, it is also possible to use an elastic body made of synthetic resin or the like in addition to rubber.

The first mounting member 11 is formed in a cylindrical shape and is connected to a vehicle body or the like as a vibration receiving portion via a bracket (not shown). The lower end opening of the first mounting member 11 is closed by the diaphragm 20.
The diaphragm 20 is made of an elastic material such as rubber or a soft resin, and is formed in a bottomed cylindrical shape. The outer peripheral surface of the diaphragm 20 is vulcanized and bonded to the inner peripheral surface of the diaphragm ring 21. The diaphragm ring 21 is fitted in the lower end portion of the first mounting member 11 via the second rubber film 13b. The diaphragm ring 21 is crimped and fixed in the lower end portion of the first mounting member 11. The upper end opening edges of the diaphragm 20 and the diaphragm ring 21 are in close contact with the lower surface of the partition member 16.

Since the diaphragm 20 is attached to the first attachment member 11 in this way, the inside of the first attachment member 11 is a liquid chamber 19 that is liquid-tightly sealed by the elastic body 13 and the diaphragm 20. .. The liquid L is sealed (filled) in the liquid chamber 19.
In the illustrated example, the bottom portion of the diaphragm 20 has a shape deep on the outer peripheral side and shallow in the central portion. However, as the shape of the diaphragm 20, various shapes known in the past can be adopted in addition to such a shape.

The liquid chamber 19 is divided into a main liquid chamber 14 and a sub liquid chamber 15 by a partition member 16. The main liquid chamber 14 has the lower surface 13c of the elastic body 13 as a part of the wall surface, and the elastic body 13 and the second rubber film 13b that tightly covers the inner peripheral surface of the first mounting member 11 and the partition member 16. It is an enclosed space, and the internal volume changes due to the deformation of the elastic body 13. The auxiliary liquid chamber 15 is a space surrounded by the diaphragm 20 and the partition member 16, and the internal volume changes due to the deformation of the diaphragm 20. The vibration isolator 10 having such a configuration is a compression type device that is attached and used so that the main liquid chamber 14 is located on the upper side in the vertical direction and the sub liquid chamber 15 is located on the lower side in the vertical direction. ..

Inside the partition member 16, for example, a storage chamber 42 in which a membrane 41 made of a rubber material or the like is housed is formed. The membrane 41 is formed in a plate shape with the front and back surfaces facing in the axial direction. The partition member 16 is formed with a plurality of first communication holes 42a communicating the accommodation chamber 42 and the main liquid chamber 14, and a plurality of second communication holes 42b communicating the accommodation chamber 42 and the auxiliary liquid chamber 15. Has been done. The number of each of the first communication hole 42a and the second communication hole 42b is the same. The inner diameters of the first communication hole 42a and the second communication hole 42b are the same. The flow path lengths of the first communication hole 42a and the second communication hole 42b are the same. The plurality of first communication holes 42a each have the same shape and the same size. The plurality of second communication holes 42b each have the same shape and the same size. The plurality of first communication holes 42a and the plurality of second communication holes 42b each face each other in the axial direction with the membrane 41 and the accommodation chamber 42 interposed therebetween.

As shown in FIG. 3, the accommodation chamber 42 is provided with a support portion 43 that supports the outer peripheral edge portion 41a of the membrane 41 from both sides in the axial direction (thickness direction). The outer peripheral edge portion 41a of the membrane 41 is a flat surface whose front and back surfaces face in the axial direction. The support portion 43 is formed on both the upper wall surface that is located on the upper side and faces downward and the lower wall surface that is located on the lower side and faces upward among the wall surfaces that define the accommodation chamber 42. The support portion 43 is formed in a ridge shape extending in the circumferential direction, and supports the outer peripheral edge portion 41a of the membrane 41 over the entire circumference. The support portion 43 continuously supports the outer peripheral edge portion 41a of the membrane 41 over the entire circumference. The support portion 43 may abut on the outer peripheral edge portion 41a of the membrane 41 from both sides in the axial direction, or may abut without contact with the support portion 43.

In the membrane 41, locking projections 41c protruding on both sides in the axial direction are formed in a portion connected to the outer peripheral edge portion 41a from the outside of the outer peripheral edge portion 41a. The locking projections 41c are continuously arranged along the outer peripheral edge portion 41a of the membrane 41 over the entire circumference thereof. The axial outer end of the locking projection 41c is located on the outermost side of the membrane 41 in the axial direction.

A locking groove 45 in which the locking projection 41c of the membrane 41 is locked to a portion of at least one of the upper wall surface and the lower wall surface defining the accommodation chamber 42, which is connected to the support portion 43 from the outside of the accommodation chamber 42. Is formed. The locking groove 45 is continuously arranged along the outer peripheral surface of the support portion 43 over the entire circumference thereof. The locking grooves 45 are formed on both the upper wall surface and the lower wall surface of the accommodation chamber 42, and the locking grooves 45 face each other in the axial direction. The locking groove 45 is arranged on the outer peripheral edge of the accommodation chamber 42.

In a plan view seen from the axial direction, the membrane 41 and the accommodation chamber 42 are formed to have the same shape and the same size as each other, as shown in FIG. The membrane 41 and the accommodation chamber 42 are formed with corner portions 41d and 42c that are pointed outward in a plan view. The corner portions 41d and 42c exhibit a curved shape of protrusions toward the outside in a plan view seen from the axial direction. The corner portions 41d and 42c are pointed outward with respect to the centroids of the membrane 41 and the accommodation chamber 42 in a plan view seen from the axial direction.

In the illustrated example, the membrane 41 and the accommodation chamber 42 have an inner peripheral edge, an outer peripheral edge that surrounds the inner peripheral edge from the outside in the radial direction, and both ends of the inner peripheral edge and both ends of the outer peripheral edge in a plan view from the axial direction. It exhibits a crescent shape with square portions 41d and 42c connected separately. In the plan view, the outer peripheral edges of the membrane 41 and the accommodation chamber 42 extend in the circumferential direction and are located on the outer peripheral portion of the partition member 16, and the central portion of the inner peripheral edge of the membrane 41 and the accommodation chamber 42 is the partition member 16. It is located in the center.
The plan-view shape of the membrane 41 and the accommodation chamber 42 may be appropriately changed, for example, to have a square shape or a star shape.

As shown in FIGS. 2 and 3, in the membrane 41, with respect to a portion of the outer peripheral edge portion 41a located at least at the corner portion 41d, the portion connected from the inside of the outer peripheral edge portion 41a can be expanded and contracted and deformed. The portion 41b is formed. The expansion / contraction portion 41b is bent in the thickness direction of the membrane 41. The telescopic portion 41b includes a top portion 41e that points toward the wall surface that defines the accommodation chamber 42. One expansion / contraction portion 41b is formed on the membrane 41 and is bent upward. The top 41e is pointed toward the upper wall surface of the containment chamber 42.

In the illustrated example, the telescopic portion 41b is continuously arranged along the outer peripheral edge portion 41a of the membrane 41 over the entire circumference thereof.
In addition, a plurality of expansion / contraction portions 41b may be arranged in a row on the membrane 41 to form a bellows shape. Further, the expansion / contraction portion 41b may be bent downward. Further, for example, the expansion / contraction portion 41b may be arranged only in the portion of the outer peripheral edge portion 41a that is continuous from the inside of the outer peripheral edge portion 41a with respect to the portion located at the corner portion 41d in the membrane 41.
Here, in the membrane 41, a plurality of protrusions are provided on the upper and lower surfaces of the main body portion located inside the expansion / contraction portion 41b. Instead of the illustrated example, the telescopic portion 41b is formed, for example, in a flat plate shape that is thinner than the thickness of the portion of the main body of the membrane 41 excluding a plurality of protrusions and extends in a direction orthogonal to the axial direction. May be good.

On the wall surface defining the accommodation chamber 42, a relief recess 44 is formed in a portion of the telescopic portion 41b facing the top 41e. In the illustrated example, the top 41e of the telescopic portion 41b faces the upper wall surface of the accommodation chamber 42. The relief recesses 44 are formed on both the upper wall surface and the lower wall surface of the accommodation chamber 42, and the relief recesses 44 face each other in the axial direction. The relief recess 44 may be formed only on the upper wall surface of the storage chamber 42. The relief recesses 44 are axially opposed to each other over the entire width direction of the telescopic portion 41b.
The escape recess 44 is formed in a portion connected to the support portion 43 from the inside of the accommodation chamber 42 on each of the upper wall surface and the lower wall surface of the accommodation chamber 42. The relief recess 44 is continuously arranged along the inner peripheral surface of the support portion 43 over the entire circumference thereof. The groove width of the relief recess 44 is wider than the groove width of the locking groove 45. The depths of the relief recess 44 and the locking groove 45 are equal to each other.

The partition member 16 is provided with a restricted passage 24 that communicates the main liquid chamber 14 and the sub liquid chamber 15. As shown in FIG. 2, the restricted passage 24 has a first communication portion 26 that opens into the main liquid chamber 14, a second communication portion 27 that opens into the sub liquid chamber 15, and a first communication portion 26 and a second communication portion. It is provided with a main body flow path 25 that communicates with 27.

The main body flow path 25 has a main flow path 31 extending from either one of the first communication portion 26 and the second communication portion 27 toward one side in the circumferential direction, and one end of the main flow path 31 in the circumferential direction. It includes a vortex chamber 34 that protrudes inward in the radial direction from the portion and forms a swirling flow of the liquid according to the flow velocity of the liquid from one side of the first communication portion 26 and the second communication portion 27.
In the illustrated example, the main flow path 31 extends from the second communication portion 27 toward one side in the circumferential direction. The vortex chamber 34 and the first communication portion 26 are directly connected.

The main flow path 31 is formed on the outer peripheral surface of the partition member 16. The main flow path 31 is arranged on the partition member 16 in an angle range of less than 360 ° about the central axis O. In the illustrated example, the main flow path 31 is arranged on the partition member 16 in an angle range exceeding 180 ° about the central axis O.

The main flow path 31 is arranged coaxially with the central axis O and is arranged coaxially with the central axis O and is located on the lower side with the lower surface of the annular upper barrier 35 which is located on the upper side and the front and back surfaces face in the axial direction. It is defined by the upper surface of the annular lower barrier 36 whose front and back surfaces face in the axial direction, and the groove bottom surface 37 which connects the inner peripheral edges of the upper barrier 35 and the lower barrier 36 and faces outward in the radial direction. There is.
The upper barrier 35 faces the main liquid chamber 14. The lower barrier 36 faces the auxiliary liquid chamber 15, and the second communication portion 27 is composed of one opening that penetrates the lower barrier 36 in the axial direction.

The vortex chamber 34 has a circular shape in a plan view seen from the axial direction, and the central axis of the vortex chamber 34 extends in the axial direction. The vortex chamber 34 is arranged at a position away from the central axis O. The vortex chamber 34 is arranged side by side with the accommodation chamber 42 in a direction orthogonal to the axial direction, and is not in communication with the accommodation chamber 42 inside the partition member 16. The internal volume and flat area of the vortex chamber 34 are smaller than the internal volume and flat area of the accommodation chamber 42.

At least a part of the vortex chamber 34 is located between the two corner portions 41d and 42c in the membrane 41 and the accommodation chamber 42, respectively, in a plan view seen from the axial direction. In the illustrated example, the portion of the vortex chamber 34 located inside in the radial direction is located between the two corner portions 41d and 42c in the membrane 41 and the accommodation chamber 42, respectively.

The vortex chamber 34 causes a swirling flow of the liquid L from the second communication portion 27 toward the first communication portion 26 according to the flow velocity of the liquid L from the other side to the one side in the circumferential direction. The vortex chamber 34 forms a swirling flow of the liquid L according to the flow velocity of the liquid L flowing in from the external communication portion 46 described later. For example, when the flow velocity of the liquid L flowing into the vortex chamber 34 is low, the swirling of the liquid L in the vortex chamber 34 is suppressed, but when the flow velocity of the liquid L is high, the swirling of the liquid L in the vortex chamber 34 is suppressed. A flow is formed. The swirling flow swirls around the central axis of the vortex chamber 34.

The external communication portion 46 extends linearly in the plan view. The outer communication portion 46 extends in the tangential direction of the inner peripheral surface of the vortex chamber 34 in the plan view. The size of the external communication portion 46 in the circumferential direction is smaller than the inner diameter of the vortex chamber 34. The axial sizes of the outer communication portion 46 and the vortex chamber 34 are equal to each other. The liquid L flowing into the vortex chamber 34 from the outer communication portion 46 flows through the outer communication portion 46, is rectified in the tangential direction, and then flows along the inner peripheral surface of the vortex chamber 34 to rotate.

Of the wall surfaces that define the vortex chamber 34, the upper wall surface that is located on the upper side and faces downward is the lower surface of the first barrier 38 whose upper surface faces the main liquid chamber 14, and is located on the lower side and faces upward. The lower wall surface is the upper surface of the second barrier 39 whose lower surface faces the auxiliary liquid chamber 15. The lower surface of the first barrier 38 and the upper surface of the second barrier 39 are flat surfaces extending in a direction orthogonal to the axial direction. The first barrier 38 and the second barrier 39 have a disk shape arranged coaxially with the central axis of the vortex chamber 34.

The first communication portion 26 includes a plurality of pores 26a penetrating the first barrier 38 facing the main liquid chamber 14. The pores 26a penetrate the first barrier 38 in the axial direction. The pores 26a may be formed in the lower barrier 36 facing the auxiliary liquid chamber 15 and provided in the second communication portion 27.

As shown in FIG. 3, the pore 26a includes a first portion 26b on the main body flow path 25 side and a second portion 26c on the main liquid chamber 14 side. The flow path length of the first portion 26b is shorter than the flow path length of the second portion 26c. The diameters of the first portion 26b and the second portion 26c are gradually reduced from the main body flow path 25 side toward the main liquid chamber 14 side, respectively. The tilt angle of the inner peripheral surface of the first portion 26b with respect to the axial direction is larger than the tilt angle of the inner peripheral surface of the second portion 26c with respect to the axial direction. The first portion 26b and the second portion 26c are continuous without a step. The inner diameter of the pore 26a is maximum at the open end on the main body flow path 25 side and minimum at the open end on the main liquid chamber 14 side.

Each of the plurality of pores 26a is smaller than the flow path cross-sectional area of the main flow path 31, and is arranged inside the vortex chamber 34 in a plan view seen from the axial direction. The plurality of pores 26a have the same shape and the same size. The minimum value of the inner diameter of each pore 26a is smaller than the inner diameter of each of the first communication hole 42a and the second communication hole 42b, and the maximum value of the inner diameter of each pore 26a is the first communication hole 42a and the second communication hole 42a. It is larger than each inner diameter of the hole 42b. The average value of the inner diameters of the pores 26a is smaller than the inner diameters of the first communication hole 42a and the second communication hole 42b.

The sum of the minimum values of the flow path cross-sectional areas in each of the plurality of pores 26a is smaller than the sum of the flow path cross-sectional areas of the plurality of first communication holes 42a and the sum of the flow path cross-sectional areas of the plurality of second communication holes 42b. It has become. The flow path cross-sectional areas of the first communication hole 42a and the second communication hole 42b are the same over the entire length.
The total sum of the minimum values of the flow path cross-sectional areas in each of the plurality of pores 26a may be, for example, 1.5 times or more and 4.0 times or less the minimum value of the flow path cross-sectional areas of the main flow path 31. In the illustrated example, the flow path cross-sectional area of the main flow path 31 is the same over the entire length. The minimum value of the flow path cross-sectional area of the pores 26a may be, for example, 25 mm ² or less, preferably 0.7 mm ² or more and 17 mm ² or less.

In the present embodiment, at least one of the plurality of pores 26a has a flow path length that is three times or more the minimum inner diameter. Preferably, the flow path length of more than half of the plurality of pores 26a is three times or more the minimum inner diameter. In the illustrated example, the flow path length is three times or more the minimum value of the inner diameter for all of the plurality of pores 26a.
When some of the plurality of pores 26a are different in size from the others, the plurality of pores 26a include at least one pore 26a whose flow path length is at least three times the minimum inner diameter. The average value of the flow path lengths of the pores 26a is 2.5 times or more and 4.5 times or less the average value of the minimum inner diameters of the plurality of pores 26a. Preferably, when some of the plurality of pores 26a are different in size from the others, the average value of the flow path lengths of the plurality of pores 26a is the minimum value of the inner diameter of each of the plurality of pores 26a. It is more than three times the average value.
Further, the flow path length of at least one of the plurality of pores 26a is longer than the flow path lengths of the first communication hole 42a and the second communication hole 42b. In the illustrated example, for all of the plurality of pores 26a, the flow path length is longer than each flow path length of the first communication hole 42a and the second communication hole 42b.

The upper barrier 35 and the first barrier 38 that define the restricted passage 24 and face the main liquid chamber 14, and the lower barrier 36 that defines the restricted passage 24 and faces the auxiliary liquid chamber 15, and Of the second barrier 39, the thickness of the first barrier 38 in which the plurality of pores 26a are formed is thicker than the thickness of each of the upper barrier 35, the lower barrier 36, and the second barrier 39. The thickness of the first barrier 38 in which the plurality of pores 26a are located is the same over the entire area. The upper surface and the lower surface of the first barrier 38 are flat surfaces extending in a direction orthogonal to the axial direction.

Here, the partition member 16 is configured such that the upper member 47 and the lower member 48 are overlapped in the axial direction. The upper member 47 and the lower member 48 are each formed in a plate shape with the front and back surfaces facing in the axial direction. The partition member 16 may be integrally formed as a whole.

The outer peripheral surface of the lower member 48 is the groove bottom surface 37. On the upper surface of the lower member 48, a first recess forming an accommodation chamber 42 with the lower surface of the upper member 47, and a second recess forming a vortex chamber 34 with the lower surface of the upper member 47. Is formed. A second communication hole 42b is formed on the bottom surface of the first recess. The bottom wall of the second recess serves as the second barrier 39. An annular lower barrier 36 is formed on the outer peripheral surface of the lower end portion of the lower member 48, which protrudes outward in the radial direction and has a second communication portion 27 formed therein.

In the upper member 47, the outer peripheral edge portion that faces the lower barrier 36 of the lower member 48 in the axial direction is the upper barrier 35. In the upper member 47, a first communication hole 42a is formed in a portion of the lower member 48 that faces the first recess in the axial direction. In the upper member 47, a first communication portion 26 is formed in a portion of the lower member 48 that faces the second recess in the axial direction, and this portion serves as a first barrier 38.

In the vibration isolator 10 having such a configuration, both mounting members 11 and 12 are relatively displaced while elastically deforming the elastic body 13 at the time of vibration input. Then, the liquid pressure in the main liquid chamber 14 fluctuates, the liquid L in the main liquid chamber 14 flows into the sub liquid chamber 15 through the restricted passage 24, and the liquid L in the sub liquid chamber 15 flows into the restricted passage 24. It flows into the main liquid chamber 14 through the main liquid chamber 14.

As described above, according to the vibration isolator 10 according to the present embodiment, the outer peripheral edge portion 41a of the membrane 41 is supported by the support portions 43 from both sides in the axial direction, so that the membrane 41 is deformed at the time of vibration input. It becomes possible to suppress the membrane 41 from colliding with the wall surface of the accommodation chamber 42, and it is possible to suppress the generation of tapping sound.
Further, in the membrane 41, a stretchable portion 41b that can be stretched and deformed is formed in a portion that is continuous from the inside of the outer peripheral edge portion 41a with respect to a portion of the outer peripheral edge portion 41a located at least at the corner portion 41d. Therefore, in spite of the fact that the outer peripheral edge portion 41a of the membrane 41 is supported by the support portion 43, the corner portion 41d of the membrane 41 is particularly difficult to be deformed at the time of vibration input. By expanding and contracting the expansion and contraction portion 41b at the time of vibration input, the corner portion 41d of the membrane 41 can be smoothly deformed by following the input vibration. As a result, even if idle vibration is input, it is possible to secure the amount of deformation of the membrane 41, and it is possible to keep the spring at the time of input of idle vibration low.
From the above, it is possible to suppress the generation of tapping sound while keeping the spring at the time of input of idle vibration low.

Further, since the expansion / contraction portion 41b is bent in the thickness direction of the membrane 41, it is possible to surely secure the expansion / contraction deformation amount while suppressing the decrease in durability.
Further, since the relief recess 44 is formed in the accommodation chamber 42, when the expansion / contraction portion 41b is expanded / contracted and deformed due to the input of vibration, the top portion of the expansion / contraction portion 41b that easily collides with the wall surface defining the accommodation chamber 42. The 41e can be made to enter the relief recess 44, and the expansion / contraction portion 41b can be smoothly expanded / contracted and deformed.
Further, since the expansion / contraction portion 41b is continuously arranged along the outer peripheral edge portion 41a of the membrane 41 over the entire circumference thereof, the spring at the time of inputting the idle vibration can be surely suppressed to a low level.

Further, since the main body flow path 25 includes the vortex chamber 34, the liquid L flows into the vortex chamber 34 from the second communication portion 27 side even when a large load (vibration) is input to the vibration isolator 10. At that time, when the flow velocity of the liquid L is sufficiently high and a swirling flow of the liquid L is formed in the vortex chamber 34, for example, energy loss due to the formation of this swirling flow or the liquid L and the vortex chamber 34 The pressure loss of the liquid L can be increased due to the energy loss due to the friction with the inner surface of the liquid L. As a result, the flow velocity of the liquid L that passes through the first communication portion 26 and flows into the main liquid chamber 14 can be suppressed. Therefore, even if a large load (vibration) is input to the vibration isolator 10, the liquid L that has passed through the first communication portion 26 and has flowed into the main liquid chamber 14 and the liquid L in the main liquid chamber 14 are It is possible to suppress the difference in flow velocity generated between the two, and it is possible to suppress the generation of a vortex caused by the difference in flow velocity and the generation of bubbles caused by this vortex.
From the above, it is possible to suppress the generation of abnormal noise caused by cavitation collapse in which bubbles collapse.

Moreover, the membrane 41 and the accommodation chamber 42 have a crescent shape when viewed in a plan view from the axial direction, and a part of the vortex chamber 34 is located between the two corner portions 41d and 42c of the crescent shape. Therefore, even though the accommodation chamber 42 and the vortex chamber 34 are arranged side by side in the direction orthogonal to the axial direction, a wide flat area of the membrane 41 can be secured. Therefore, even though the outer peripheral edge portion 41a of the membrane 41 is supported by the support portion 43 and the membrane 41 has the corner portion 41d, and the membrane 41 is not easily deformed, when the idle vibration is input, The membrane 41 can be easily deformed smoothly.

Further, since the first communication portion 26 includes a plurality of pores 26a penetrating the first barrier 38 facing the main liquid chamber 14, the liquid L flows from the restricted passage 24 to the main liquid chamber 14 through the plurality of pores 26a. At the time of inflow, each pore 26a flows while being pressure-lossed by the first barrier 38 in which these pores 26a are formed, so that the flow velocity of the liquid L flowing into the main liquid chamber 14 can be suppressed. Moreover, since the liquid L flows through a plurality of pores 26a instead of a single pore 26a, the liquid L can be branched into a plurality of pores and circulated, and the liquid L that has passed through the individual pores 26a can be circulated. The flow velocity can be reduced.
Since these effects are exerted on the liquid L whose pressure is lost by the vortex chamber 34, it is possible to reliably suppress the generation of bubbles in the main liquid chamber 14.
Further, even if bubbles are generated in the restricted passage 24 instead of the main liquid chamber 14, the generated bubbles are separated from each other in the main liquid chamber 14 by allowing the liquid L to pass through the plurality of pores 26a. It is possible to prevent the bubbles from merging and growing, and it is possible to easily maintain the state in which the bubbles are finely dispersed.
As described above, it is possible to suppress the generation of bubbles themselves, and even if bubbles are generated, it is possible to easily maintain the state in which the bubbles are finely dispersed, so that even if cavitation collapse occurs, it will occur. Abnormal noise can be suppressed to a small level.

The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

For example, in the above-described embodiment, the front and back surfaces of the membrane 41 are oriented in the axial direction, but the membrane 41 may be arranged with the front and back surfaces oriented in the radial direction, for example.
Further, both the first communication portion 26 and the second communication portion 27 may adopt a configuration in which the pores 26a are not provided, or both the first communication portion 26 and the second communication portion 27 have the pores 26a. A configuration having the above may be adopted.
Further, although the configuration in which the partition member 16 orbits the partition member 16 about once is shown as the main flow path 31, a configuration in which the partition member 16 orbits the partition member 16 longer than one circumference may be adopted.
Further, the main flow path 31 may be appropriately changed, for example, extending in the axial direction.
Further, it is not necessary to form the relief recess 44 and the locking groove 45 in the storage chamber 42.
Further, a configuration having no vortex chamber 34 may be adopted as the main body flow path 25.
Further, the flow path length of the pore 26a may be less than three times the minimum value of the inner diameter of the pore 26a.
Further, the thickness of the first barrier 38 in which the plurality of pores 26a are formed may be set to be equal to or less than the thickness of the upper barrier 35, the lower barrier 36, and the second barrier 39.
Further, the flow path length of the pores 26a may be set to be equal to or less than the flow path lengths of the first communication hole 42a and the second communication hole 42b.

Further, in the above embodiment, the compression type anti-vibration device 10 in which a positive pressure acts on the main liquid chamber 14 by the action of a supporting load has been described, but the main liquid chamber 14 is located on the lower side in the vertical direction and The auxiliary liquid chamber 15 is attached so as to be located on the upper side in the vertical direction, and can be applied to a suspension type vibration isolator in which a negative pressure acts on the main liquid chamber 14 by the action of a supporting load.

Further, in the above embodiment, the partition member 16 partitions the liquid chamber 19 in the first mounting member 11 into a main liquid chamber 14 having an elastic body 13 as a part of a wall surface and a sub liquid chamber 15. It is not limited to this. For example, instead of providing the diaphragm 20, a pair of elastic bodies 13 may be provided in the axial direction, and instead of providing the auxiliary liquid chamber 15, a pressure receiving liquid chamber having the elastic body 13 as a part of the wall surface may be provided. good. For example, the partition member 16 partitions the liquid chamber 19 in the first mounting member 11 in which the liquid L is sealed into the first liquid chamber 14 and the second liquid chamber 15, and the first liquid chamber 14 and the second liquid chamber 15 are used. It is possible to appropriately change to another configuration in which at least one of both liquid chambers has the elastic body 13 as a part of the wall surface.

Further, the vibration isolator 10 according to the present invention is not limited to the engine mount of the vehicle, and can be applied to other than the engine mount. For example, it can be applied to the mount of a generator mounted on a construction machine, or it can be applied to the mount of a machine installed in a factory or the like.

In addition, it is possible to appropriately replace the components in the embodiment with well-known components without departing from the spirit of the present invention, and the above-mentioned modifications may be appropriately combined.

10 Anti-vibration device 11 1st mounting member 12 2nd mounting member 13 Elastic body 14 Main liquid chamber (1st liquid chamber)
15 Secondary liquid chamber (second liquid chamber)
16 Partition member 19 Liquid chamber 24 Restricted passage 25 Main body flow path 26 First communication part 26a Pore 27 Second communication part 31 Main flow path 34 Vortex chamber 41 Membrane 41a Outer peripheral edge 41b Telescopic part 41d Square part 41e Top 42 Storage room 43 Support 44 Relief recess L Liquid O Central axis

Claims (4)

A cylindrical first mounting member connected to either one of the vibration generating portion and the vibration receiving portion, and a second mounting member connected to the other.
An elastic body that elastically connects these two mounting members,
A partition member for partitioning the liquid chamber in the first mounting member in which the liquid is sealed into the first liquid chamber and the second liquid chamber is provided, and the liquid chamber is provided.
The partition member accommodates a restricted passage connecting the first liquid chamber and the second liquid chamber, and a storage chamber communicating with the first liquid chamber and the second liquid chamber while accommodating the membrane. It is a liquid-filled type anti-vibration device that is formed.
The accommodation chamber is provided with support portions that support the outer peripheral edge portion of the membrane from both sides in the thickness direction.
The membrane is formed with corners that are pointed outward in a plan view from the axial direction along the central axis of the first mounting member.
In the membrane, a stretchable portion that can be stretched and deformed is formed in a portion that is continuous from the inside of the outer peripheral edge portion with respect to a portion of the outer peripheral edge portion that is located at least at the corner portion.
The restricted passage includes a first communication portion that opens into the first liquid chamber, a second communication portion that opens into the second liquid chamber, and a main body flow path that communicates the first communication portion with the second communication portion. Equipped with
The main body flow path
A main flow path extending from one of the first communication portion and the second communication portion toward one side in the circumferential direction along the central axis of the first attachment member.
It protrudes inward in the radial direction from one end in the circumferential direction in the main flow path, and forms a swirling flow of the liquid according to the flow velocity of the liquid flowing in through the outer communication portion from the one communication portion side. With a vortex chamber,
The vortex chamber has a circular shape when viewed from the axial direction along the central axis, and is arranged side by side with the accommodation chamber in a direction orthogonal to the axial direction.
The outer communication portion extends in the tangential direction of the inner peripheral surface of the vortex chamber in the plan view.
The liquid flowing into the vortex chamber from the outer communication portion flows through the outer communication portion, is rectified in the tangential direction, and then swirls by flowing along the inner peripheral surface of the vortex chamber.
The membrane and the accommodation chamber are formed to have the same shape and the same size in a plan view seen from the axial direction.
The membrane and the containment chamber have a crescent shape in a plan view from the axial direction, and at least a part of the vortex chamber is located between the two corners of the crescent shape. Anti-vibration device as a feature. The vibration isolator according to claim 1, wherein the telescopic portion is bent in the thickness direction of the membrane. The telescopic portion comprises a pointed top towards the wall defining the containment chamber.
The anti-vibration device according to claim 2, wherein a relief recess is formed in a portion of the wall surface defining the accommodation chamber facing the top. The vibration isolator according to any one of claims 1 to 3, wherein the telescopic portion is continuously arranged along the outer peripheral edge portion of the membrane over the entire circumference thereof.

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