CN215487371U

CN215487371U - Vibration-proof device

Info

Publication number: CN215487371U
Application number: CN202023107008.8U
Authority: CN
Inventors: 伊藤优歩; 井上敏郎
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 2020-12-22
Filing date: 2020-12-22
Publication date: 2022-01-11
Anticipated expiration: 2030-12-22

Abstract

The utility model provides a vibration isolator which can disperse the load applied to a buffer member to an internal magneto-rheological elastomer which can be controlled in rigidity change so as to improve the strength and durability of the buffer member and further improve the structural strength and durability of the vibration isolator. The vibration isolation device includes: an inner tube which is made of a magnetic body and has a hollow shaft portion for fastening to the vehicle; an outer cylinder that is made of a magnetic material and is disposed coaxially with the inner cylinder on the radially outer side of the inner cylinder; an elastic member disposed between the inner cylinder and the outer cylinder; and a coil for applying a magnetic field for changing the rigidity of the elastic member, wherein the elastic member is composed of an internal magnetorheological elastomer and a buffer material which are adjacently arranged, and the buffer material is arranged at a position of the vibration damping device for bearing the maximum load.

Description

Vibration-proof device

Technical Field

The present invention relates to a vibration isolator to be mounted on a mounting bracket for mounting a sub-frame.

Background

Conventionally, a vibration isolating and noise reducing device for a vehicle is provided to suppress transmission of vibration generated by a driving force distribution device supported by a subframe and input (vibration force) from a road surface to a vehicle body side. For example, patent document 1 discloses a mount using a magnetorheological Elastomer (MRE) disposed on a subframe on which a drive source of a vehicle is mounted (paragraphs [0024], [0025], fig. 2 of patent document 1). Patent document 1 discloses a technique for improving the cornering performance of a vehicle by increasing the elastic modulus of a magnetorheological elastomer to increase the rigidity (yaw stiffness) of a mount at cornering with a large torque difference between right and left wheels (paragraph [0009] of patent document 1). Further, patent document 2 describes a direction of a change in rigidity caused by a magnetic field (magnetic field) of a magnetorheological elastomer (paragraphs [0028] - [0031] of patent document 2).

[ Prior art documents ]

[ patent document ]

[ patent document 1] Japanese patent laid-open publication No. 6047087

[ patent document 2] International publication No. 2016/148011

SUMMERY OF THE UTILITY MODEL

[ problem to be solved by the utility model ]

However, conventionally, a mount seat and a magnetorheological elastic body are provided in a subframe in a portion where a vehicle body (main frame) of a vehicle supports the subframe of the vehicle, so that elastic forces (resistances) in respective directions against forces applied from a plurality of directions to the mount seat can be adjusted.

Accordingly, although it has been proposed in the related art to use a magnetorheological elastomer so as to be able to vary the spring force of the mount in each application direction, there has been no discussion in the related art on how to increase the rigidity of the magnetorheological elastomer to which a current is applied, and how to disperse the load when the mount receives a load.

The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a vibration isolator which can be mounted on a vehicle, can adjust the elastic force in each direction of a mount base on a sub-frame of a drive source of the vehicle with respect to a force applied from a plurality of directions to be variable, can increase the rigidity of a magnetorheological elastomer, can obtain a greater change in the rigidity of the mount base, and can improve the structural strength and durability of the vibration isolator.

[ means for solving problems ]

In order to achieve the above object, the present invention provides a vibration isolator mountable to a vehicle, the vibration isolator comprising: an inner tube which is made of a magnetic body and has a hollow shaft portion for fastening to the vehicle; an outer cylinder that is made of a magnetic material and is disposed coaxially with the inner cylinder on the radially outer side of the inner cylinder; an elastic member disposed between the inner cylinder and the outer cylinder; and a coil for applying a magnetic field for changing the rigidity of the elastic member, wherein the elastic member is composed of an internal magnetorheological elastomer and a buffer material which are adjacently arranged, and the buffer material is arranged at a position of the vibration damping device for bearing the maximum load.

In this way, by disposing the damper at the position where the maximum load is applied and disposing the inner magnetorheological elastomer adjacent to the damper, the load applied to the damper can be dispersed to the inner magnetorheological elastomer which can be controlled in terms of rigidity change, so that the strength and durability of the damper can be improved, and the structural strength and durability of the vibration damping device can be improved.

In an embodiment of the present invention, the magnetic particles of the internal magnetorheological elastomer are arranged in a plurality of magnetic particle rows in the same direction, and the plurality of magnetic particle rows are radially arranged on a cross section perpendicular to an axial direction of the inner cylinder.

In this way, by arranging the plurality of magnetic particles in a radial shape on the cross section perpendicular to the axial direction of the inner cylinder, the load applied to the damper can be effectively dispersed, and the load directly input to the internal magnetorheological elastomer can be effectively handled.

In one embodiment of the present invention, the magnetic particles of the inner magnetorheological elastomer are arranged in parallel to the axial direction of the inner cylinder.

In this way, by arranging the magnetic particles of the internal magnetorheological elastomer so as to be aligned parallel to the axial direction of the inner cylinder, the rigidity in the axial direction can be controlled.

In one embodiment of the present invention, the inner cylinder has a convex portion protruding toward the outer cylinder, and the damper abuts against a protruding surface of the convex portion.

In this way, by providing the buffer member in contact with the protruding surface of the protruding portion of the inner tube, the load applied to the buffer member can be effectively dispersed, and the strength and durability of the buffer member can be further improved.

In one embodiment of the present invention, the protruding portion divides the coil into two in the axial direction of the inner tube, and the protruding portion is located between the two divided coils in the axial direction.

In this way, by disposing the convex portion so as to be located between the coils divided into two in the axial direction, it is possible to apply a current to the coils divided into two to generate magnetic fields in different directions, so that the inner magnetorheological elastomer can obtain a greater change in rigidity.

In one embodiment of the present invention, the inner magnetorheological elastomers are arranged to face each other with the inner cylinder interposed therebetween, and the damper members are arranged to face each other with the inner cylinder interposed therebetween, as viewed in a cross-sectional view perpendicular to the axial direction of the inner cylinder.

In this way, since the inner magnetorheological elastomer and the damper are arranged to face each other with the inner cylinder interposed therebetween when viewed in a cross-sectional plane perpendicular to the axial direction of the inner cylinder, and the damper is located at a position where the maximum load is applied, even when a load is applied to the damper during the traveling of the vehicle, the load can be effectively dispersed to the adjacent inner magnetorheological elastomers.

In one embodiment of the present invention, the vibration damping device is used for a bushing of a suspension arm of a vehicle.

In this way, by disposing the vibration isolator in the bushing of the suspension arm of the vehicle, the rigidity of the bushing of the suspension arm can be varied, so that the vehicle can achieve both of the ride quality performance and the vibration noise performance, wherein the rigidity can be increased when the ride quality performance is required and the rigidity can be decreased when the vibration noise performance is required, thereby providing the vibration isolator capable of achieving both of the ride quality performance and the vibration noise performance.

[ effects of the utility model ]

In view of the above, the vibration isolator according to the present invention can adjust the elastic force in each direction with respect to the force applied from a plurality of directions of the mount base on the sub-frame of the drive source of the vehicle to be variable by disposing the inner magnetorheological elastomer and the cushion member adjacent to each other between the inner cylinder and the outer cylinder, and can increase the rigidity of the inner magnetorheological elastomer by disposing the inner magnetorheological elastomer so as to be divided into a plurality of portions between the inner cylinder and the outer cylinder and by fitting the cushion member disposed at the position receiving the maximum load, thereby achieving a greater change in the rigidity of the mount base, and can increase the structural strength and durability of the vibration isolator by disposing the cushion member. In addition, when the vibration isolator according to the present invention is disposed in the bushing of the suspension arm of the vehicle, the rigidity of the bushing of the suspension arm can be changed, and therefore, the rigidity can be increased when the ride quality performance is required, and the rigidity can be decreased when the vibration noise performance is required, and thus, the vibration isolator can achieve both the ride quality performance and the vibration noise performance.

In order to make the aforementioned and other features and advantages of the utility model more comprehensible, embodiments accompanied with figures are described in detail below.

Drawings

Fig. 1 is a partially omitted cross-sectional view schematically showing a state in which a mount provided with a vibration damping device according to an embodiment of the present invention is fastened to a subframe so as to be attached to a vehicle body (main frame).

Fig. 2 is a vertical sectional view schematically showing components of the vibration isolator of fig. 1.

Fig. 3A is a schematic diagram showing a state of a magnetorheological elastomer structure having a basic structure in a case where an external force in a shearing direction is not applied.

Fig. 3B is a schematic view showing a state of a magnetorheological elastomer structure having a basic structure which is laterally deflected by an external force in a shear direction.

FIG. 3C is a schematic view showing a state in which a resistance force is increased in a magnetorheological elastomer structure of a basic structure when a magnetic field in a vertical direction is applied.

Fig. 4A is a partial sectional view schematically showing the vibration isolator of fig. 2 in the axial direction.

Fig. 4B is a cross-sectional view schematically showing a position of the inner tube of fig. 4A where the convex portion is provided in the radial direction.

Description of reference numerals:

10: vibration device

12: main frame

16: auxiliary frame

18: mounting seat

36: bolt

38: nut

30: outer cylinder

40: inner cylinder

42: convex part

42S: projecting surface

50: coil

60: end magnetorheological elastomer

70: elastic member

72: internal magnetorheological elastomers

74: buffer piece

100: magnetorheological elastomer structure

101: upper supporting body

102: lower support

104: iron powder

106: iron powder

108: elastic body

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the embodiments described below, when reference is made to a number, an amount, or the like, the scope of the present invention is not necessarily limited to the number, the amount, or the like, unless otherwise specified. In the following embodiments, each constituent element is not necessarily essential to the present invention unless otherwise specified. In the following description, when there are a plurality of embodiments, the characteristic portions of the respective embodiments can be appropriately combined and previously determined from the beginning, unless otherwise specified.

Hereinafter, a vibration damping device to be mounted on a mounting bracket for a sub-frame according to the present invention will be described in detail with reference to the accompanying drawings by referring to preferred embodiments.

Fig. 1 is a partially omitted cross-sectional view schematically showing a state in which a mount provided with a vibration damping device according to an embodiment of the present invention is fastened to a subframe so as to be attached to a vehicle body (main frame). Fig. 2 is a vertical sectional view schematically showing components of the vibration isolator of fig. 1. Referring to fig. 1 and 2, the vibration isolator 10 according to the present invention is mounted on a mounting seat 18 of a vehicle, and a subframe 16 of the vehicle is coupled to a main frame (vehicle body) 12 via the mounting seat 18. The steered wheels of the vehicle are coupled to a steering wheel (not shown) via a rack mechanism and a steering shaft, and are suspended from the main frame 12 and the sub-frame 16 by a suspension device (not shown).

As shown in fig. 1 and 2, the vibration isolator 10 is composed of a cylindrical outer cylinder 30, a cylindrical inner cylinder 40, an end magnetorheological elastic body 60 as a magnetorheological elastic body, and a coil 50. The outer cylinder 30 is made of a magnetic material embedded in the subframe 16, and the inner cylinder 40 is made of a magnetic material, and is inserted by a bolt (through bolt) 36 and fastened to the main frame 12 by the bolt 36 and a nut 38. The end magnetorheological elastomers 60 are disposed between the inner cylinder 40 and the outer cylinder 30 and located at both ends of the outer cylinder 30 in the axial direction. The outer cylinder 30 is arranged coaxially with the inner cylinder 40 on the radially outer side.

A cylindrical coil (excitation coil) 50 is housed in a side wall of the cylindrical inner tube 40, and the coil 50 generates a magnetic field (magnetic flux) having an intensity corresponding to the magnitude of a coil excitation current supplied from a vehicle Control Unit (ECU) (not shown). The flange-like end magnetorheological elastic bodies 60 are held in the flange-like spaces formed at both ends in the axial direction of the outer cylinder 30, that is, the end magnetorheological elastic bodies 60 are held in a state of being bound in the flange-like spaces formed at both ends in the axial direction of the outer cylinder 30. The end magnetorheological elastomer 60 is a member whose viscoelastic properties vary depending on the magnitude of the magnetic field generated by the coil 50. Specifically, the end magnetorheological elastomer 60 is made of an elastic material such as a rubber material to which magnetic powder such as iron powder is added, and has a property that the rigidity is low in a state where the magnetic field generated by the coil 50 is absent (or low), and the rigidity is increased depending on the magnitude of the magnetic field in a state where the magnetic field generated by the coil 50 is present.

First, before describing the structure and the operation and effects of the vibration damping device 10 according to the present embodiment, the operation and effects of the magnetorheological elastomer structure (structure of a magnetorheological elastomer) 100 having a basic structure will be described with reference to fig. 3A, 3B, and 3C for the sake of easy understanding. Fig. 3A is a schematic diagram showing a state of a magnetorheological elastomer structure having a basic structure in a case where an external force in a shearing direction is not applied. Fig. 3B is a schematic view showing a state of a magnetorheological elastomer structure having a basic structure which is laterally deflected by an external force in a shear direction. FIG. 3C is a schematic view showing a state in which a resistance force is increased in a magnetorheological elastomer structure of a basic structure when a magnetic field in a vertical direction is applied.

Fig. 3A shows a state of the magnetorheological elastomer structure 100 in a case where no external force in the shearing direction (shearing stress) is applied. In the magnetorheological elastomer structure 100 in fig. 3A, the magnetorheological elastic material 108 in which the elastic body 106 is cured is disposed between the upper and

lower support bodies

101 and 102, and the elastic body 106 is, for example, silicone rubber or the like containing iron powder 104 as magnetic particles oriented in the vertical direction.

As shown in fig. 3B, for example, when an external force in the shearing direction is applied to the upper support 101 in a state where the lower support 102 is fixed to a base (not shown), the magnetorheological elastic member 108 is flexed in the lateral direction to which the external force in the shearing direction is applied. In this case, the elastic body 106 generates resistance to the external force in the shear direction to return to its original shape.

As shown in fig. 3C, when a magnetic flux (magnetic field) indicated by a broken-line arrow in the vertical direction is applied, the resistance of the iron powder 104 in the direction indicated by a short arrow to return to the direction corresponding to the magnetic flux direction increases. The resistance shown by the short arrow from right to left increases on the upper side of the magnetorheological elastomer structure 100 and the resistance shown by the arrow from left to right increases on the lower side of the magnetorheological elastomer structure 100. The larger the magnitude of the magnetic field, the larger the value of the resistance. Thus, in the magnetorheological elastomer structure 100, the resistance to the external force in the shear direction can be changed (varied) according to the magnitude of the applied magnetic field.

Accordingly, for example, in the mount 18 to which the vibration isolator 10 of the present invention is mounted, the control device of the vehicle, not shown, controls so that the larger the yaw rate obtained by the yaw rate sensor and the larger the vehicle speed obtained by the vehicle speed sensor, the larger the coil exciting current of the coil 50 becomes, whereby the resistance of the mount 18 can be increased, that is, the elasticity of the mount 18 can be fixed (variable). Therefore, for example, when traveling on a straight road or cruising on an expressway, the control device of the vehicle can set the coil exciting current to a zero value or a small value to soften the elasticity of the mount 18 and cut off the forced vibration input from the internal combustion engine or the electric motor, and in addition, can block the vibration input transmitted from the road surface to the main frame 12 via the suspension, and as a result, can suppress the sound and vibration felt by the passenger in the vehicle cabin, and can improve the comfort. On the other hand, in a so-called curved road or a winding road, the control device of the vehicle increases the coil exciting current to fix (vary) the mount 18, thereby improving the vehicle drivability (turning performance) and the steering stability of the driver.

Fig. 4A is a partial sectional view schematically showing the vibration isolator of fig. 2 in the axial direction. Fig. 4B is a cross-sectional view schematically showing a position in the radial direction where the convex portion is provided in the inner tube of the vibration isolator of fig. 4A. Referring to fig. 2 and 4, the vibration isolator 10 includes an inner cylinder 40, an outer cylinder 30, an end magnetorheological elastomer 60, a coil 50 as an excitation coil, and an elastic member 70 including an inner magnetorheological elastomer 72 and a damper 74. The inner tube 40 is made of a magnetic material and has a hollow shaft portion for fastening to the main frame 12. The outer cylinder 30 is made of a magnetic material, and is disposed coaxially with the inner cylinder 40 on the radially outer side of the inner cylinder 40. The end magnetorheological elastomers 60 are disposed between the inner cylinder 40 and the outer cylinder 30 and located at both ends of the outer cylinder 30 in the axial direction. The coil 50 applies a magnetic field that changes the viscoelasticity (i.e., stiffness) of the end magnetorheological elastomer 60 and the inner magnetorheological elastomer 72. The end magnetorheological elastomers 60 and the inner magnetorheological elastomer 72 are each composed of a plurality of magnetorheological elastomers having different arrangements of magnetic particles such as iron powder 104.

As shown in fig. 4A and 4B, in the present embodiment, the vibration isolator 10 is provided with an elastic member 70 between the inner tube 40 and the outer tube 30 and at a position substantially in the middle in the axial direction. The elastic member 70 is composed of an inner magnetorheological elastomer 72 and a buffer 74, wherein the material of the inner magnetorheological elastomer 72 is the same as that of the end magnetorheological elastomer 60, for example, the material of the buffer 74 is rubber (rubber), raw rubber (raw rubber), synthetic rubber (synthetic rubber), or other materials with cushioning or flexibility, elasticity or force absorption property, or vibration-proof property.

Accordingly, in the present embodiment, the vibration isolator 10 is provided with the end magnetorheological elastomers 60 disposed between the inner cylinder 40 and the outer cylinder 30 at both ends in the axial direction, and further provided with the inner magnetorheological elastomer 72 having the same property as the end magnetorheological elastomer 60 and the damper 74 disposed adjacent thereto, between the inner cylinder 40 and the outer cylinder 30 at a substantially middle position in the axial direction. Referring to fig. 4B, the buffer 74 is disposed at a position of the anti-vibration device 10 that receives the maximum load.

As shown in fig. 4A and 4B, by disposing the inner magnetorheological elastomer 72 and the damper 74 adjacent to each other between the inner cylinder 40 and the outer cylinder 30 and disposing the damper 74 at a position where the maximum load is always received in the radial direction, the elastic force in each direction with respect to the force applied from a plurality of directions of the mount 18 on the subframe 16 of the drive source of the vehicle can be adjusted to be variable, and by disposing the inner magnetorheological elastomer 72 so as to be divided into a plurality of parts between the inner cylinder and the outer cylinder and fitting the damper 74 disposed at the position where the maximum load is received, the rigidity of the inner magnetorheological elastomer 72 can be increased, and the structural strength and durability of the vibration isolator 10 can be improved by disposing the damper 74 in addition to obtaining a larger change in the rigidity of the mount 18. As described above, by disposing the damper 74 at the position receiving the maximum load and disposing the inner magnetorheological elastic body 72 adjacent to the damper 74, the load applied to the damper 74 can be dispersed to the inner magnetorheological elastic body 72 whose rigidity can be controlled, so that the strength and durability of the damper 74 can be improved, and the structural strength and durability of the vibration damping device 10 can be improved.

In the present embodiment, as shown in fig. 4A and 4B, the magnetic particles of the internal magnetorheological elastomer 72 are arranged in a plurality of magnetic particle rows in the same direction, and the plurality of magnetic particle rows are radially arranged on a cross section perpendicular to the axial direction of the inner cylinder 40. For example, the magnetic particles of the inner magnetorheological elastomer 72 may be arranged in parallel along the axial direction, and the magnetic particles arranged in parallel along the axial direction are arranged into a plurality of magnetic particle rows arranged in parallel with each other, and the plurality of magnetic particle rows are radially arranged as viewed from a cross section perpendicular to the axial direction (i.e., a radial cross section).

In this way, by arranging the plurality of magnetic particles radially in a cross section perpendicular to the axial direction of the inner cylinder 40, that is, in a radial cross section, the load applied to the damper 74 can be effectively dispersed, and the load directly input to the inner magnetorheological elastomer 72 can be effectively handled. By arranging the magnetic particles of the inner magnetorheological elastomer 72 so as to be aligned parallel to the axial direction of the inner cylinder, the rigidity in the axial direction can be controlled.

In the present embodiment, as shown in fig. 4A and 4B, the inner tube 40 has the convex portion 42 protruding toward the outer tube 30, and the cushion 74 abuts against the protruding surface 42S of the convex portion 42. In the vibration isolator 10 of the present embodiment, the convex portion 42 protruding toward the inner peripheral surface of the outer cylinder 30 is provided at a substantially middle position in the axial direction on the outer peripheral surface of the inner cylinder 40, a gap is provided between the protruding surface 42S of the convex portion 42 and the inner peripheral surface of the outer cylinder 30, and the elastic member 70 composed of the inner magnetorheological elastomer 72 and the cushion 74 disposed adjacent to each other is provided in the gap.

In the present embodiment, the elastic member 70 is formed in a ring shape between the convex portion 42 of the inner cylinder 40 and the outer cylinder 30, and the inner magnetorheological elastomer 72 is provided such that the two-divided inner magnetorheological elastomer 72 faces each other with the inner cylinder 40 interposed therebetween, and the two-divided damper 74 is provided such that the two-divided damper 74 faces each other with the inner cylinder 40 interposed therebetween, when viewed in a cross-sectional view perpendicular to the axial direction at the position of the convex portion 42 of the inner cylinder 40. As shown in fig. 4B, the inner magnetorheological elastomer 72 and the damper 74 are divided into two parts, and the inner magnetorheological elastomer 72, the damper 74, the inner magnetorheological elastomer 72, and the damper 74 are arranged adjacent to each other in this order between the protruding surface 42S of the protrusion 42 of the inner cylinder 40 and the outer cylinder 30, and are in a complete ring shape. The

dampers

74 and 74 are disposed facing each other at the position of the inner tube 40 that receives the maximum load.

As described above, since the inner magnetorheological elastomer 72 and the damper 74 are arranged to face each other across the inner cylinder 40 when viewed in a cross section perpendicular to the axial direction of the inner cylinder 40, and the damper 74 is located at a position to receive the maximum load, even if a load is applied to the damper 74 during vehicle traveling, the load can be effectively dispersed to the inner magnetorheological elastomer 72 disposed adjacent to the damper 74, thereby enhancing the strength and durability of the damper 74 and enhancing the structural strength and durability of the vibration damping device 10.

In the present embodiment, as shown in fig. 4A, the protruding portion 42 divides the coil 50 into two in the axial direction of the inner tube 40 such that the protruding portion 42 is located between the two-divided coils 50 in the axial direction. For example, in fig. 4A, the convex portion 42 is located between the

coils

50 and 50, and a current is applied to the

coils

50 and 50 to generate magnetic fields in different directions in the coils 50, that is, a current is applied to each coil 50 to generate magnetic fields in opposite directions in the coil 50 and the other coil 50. In this way, by disposing the convex portion 42 so as to be axially located between the coils 50 divided into two, it is possible to apply a current to the

coils

50 and 50 divided into two to generate magnetic fields in different directions, and the inner magnetorheological elastic body 72 can obtain a greater change in rigidity.

In the present embodiment, the vibration isolator 10 is used for a bushing of a suspension arm (for example, the subframe 16) of a vehicle. The vibration isolator 10 of the present invention is a structure that can be used as a suspension arm bushing and a subframe mounting bushing, and is a mounting bushing that uses a magnetorheological elastomer (for example, an end portion magnetorheological elastomer 60 and an elastic member 70 composed of an inner magnetorheological elastomer 72 and a buffer 74), and the rigidity of the mounting bushing can be controlled by applying an electric current to the magnetorheological elastomer, and the rigidity of the suspension arm bushing and the subframe mounting bushing can be changed to increase the rigidity when a ride quality performance (ride quality performance) is required and to decrease the rigidity when a vibration noise performance (vibration noise performance) is required, thereby enabling both the ride quality performance and the vibration noise performance to be achieved.

As described above, by disposing the vibration isolator 10 in the bushing of the suspension arm (for example, the subframe 16) of the vehicle, it is possible to make the rigidity of the bushing of the suspension arm variable, so that it is possible to achieve both the ride quality performance and the vibration noise performance of the vehicle, in which the rigidity can be increased when the ride quality performance is required and the rigidity can be decreased when the vibration noise performance is required, and thus it is possible to provide a vibration isolator which can achieve both the ride quality performance and the vibration noise performance.

In addition, the vibration isolator 10 according to the present invention is provided with the magnetorheological elastomers, for example, the end portion magnetorheological elastomer 60 and the elastic member 70 composed of the inner magnetorheological elastomer 72 and the cushion 74, and by disposing the inner magnetorheological elastomer 72 so as to be divided into a plurality of parts between the inner cylinder 40 and the outer cylinder 30 and by fitting the cushion 74 provided at the position receiving the maximum load, it is possible to enhance the rigidity of the inner magnetorheological elastomer 72, and to obtain an effect of increasing the range of the change in the rigidity of the mount 18, and by providing the cushion 74, it is possible to enhance the structural strength and durability of the vibration isolator 10. Since the vibration damping device 10 according to the present invention is disposed in the bushing of the suspension arm of the vehicle, the range of rigidity change of the bushing of the suspension arm can be increased, and thus the function of enabling the vehicle to achieve both ride quality performance and vibration noise performance can be further enhanced.

In view of the above, the vibration isolator according to the present invention can adjust the elastic force in each direction of the mount base on the sub-frame of the drive source of the vehicle to be variable by disposing the internal magnetorheological elastomer between the inner cylinder and the outer cylinder, and can improve the rigidity of the internal magnetorheological elastomer by disposing the internal magnetorheological elastomer so as to be divided into a plurality of portions between the inner cylinder and the outer cylinder and by fitting the cushion member disposed at the position receiving the maximum load, and can achieve a greater change in the rigidity of the mount base, and can improve the structural strength and durability of the vibration isolator by disposing the cushion member, and can improve the magnetic flux density inside the magnetorheological elastomer and achieve a greater change in the rigidity of the mount base. In addition, when the vibration isolator according to the present invention is disposed in the bushing of the suspension arm of the vehicle, the magnetic substance is provided inside the magnetorheological elastomer of the vibration isolator according to the present invention, so that the effect of increasing the magnetic flux density and increasing the amplitude of the rigidity change can be obtained, and the function of enabling the vehicle to achieve both the ride quality performance and the vibration noise performance can be further enhanced.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. An antivibration device mountable to a vehicle, comprising:

an inner tube which is made of a magnetic body and has a hollow shaft portion for fastening to the vehicle;

an outer cylinder that is made of a magnetic material and is disposed coaxially with the inner cylinder on the radially outer side of the inner cylinder;

an elastic member disposed between the inner cylinder and the outer cylinder; and

a coil for applying a magnetic field for changing the rigidity of the elastic member,

the elastic member is composed of an inner magnetorheological elastomer and a buffer which are adjacently arranged, and the buffer is arranged at the position of the vibration isolator bearing the maximum load.

2. The vibration isolator according to claim 1, wherein the magnetic particles of the inner magnetorheological elastomer are arranged in a plurality of magnetic particle rows in the same direction, and the plurality of magnetic particle rows are radially arranged in a cross-sectional plane perpendicular to the axial direction of the inner cylinder.

3. The vibration isolator as claimed in claim 1, wherein the magnetic particles of the inner magnetorheological elastomer are arranged in parallel with the axial direction of the inner cylinder.

4. The vibration isolator according to any one of claims 1 to 3, wherein the inner tube has a convex portion that protrudes toward the outer tube, and the damper abuts against a protruding surface of the convex portion.

5. The vibration isolator according to claim 4, wherein the protruding portion divides the coil into two in the axial direction of the inner tube, and the protruding portion is located between the two-divided coils in the axial direction.

6. The vibration isolator according to any one of claims 1 to 3, wherein said inner magnetorheological elastomers are disposed so as to face each other with said inner cylinder sandwiched therebetween in a cross-sectional plane perpendicular to the axial direction of said inner cylinder, and said damper members are disposed so as to face each other with said inner cylinder sandwiched therebetween in a cross-sectional plane perpendicular to the axial direction of said inner cylinder.

7. Vibration isolator according to any of claims 1 to 3, characterized in that it is used for bushings of suspension arms of vehicles.