阅读说明：本技术 液体填充衬套组件 (Liquid filled liner assembly ) 是由 伊藤优步 井上敏郎 于 2020-02-13 设计创作，主要内容包括：液体填充衬套组件。该液体填充衬套组件包括：内管状构件(11)；外管状构件(12),其以与所述内管状构件同轴的关系设置；以及弹性构件(13),其插设在所述内管状构件和所述外管状构件之间,其中,不仅能够自由地选择所述液体填充衬套组件在横向方向上的刚度,而且能够自由地选择所述液体填充衬套组件在旋转方向和/或轴向方向上的刚度。(A liquid filled liner assembly. The liquid-filled liner assembly includes: an inner tubular member (11); an outer tubular member (12) disposed in coaxial relationship with the inner tubular member; and an elastic member (13) interposed between the inner and outer tubular members, wherein not only the rigidity of the liquid-filled liner assembly in the lateral direction but also the rigidity of the liquid-filled liner assembly in the rotational and/or axial direction can be freely selected.)

1. A liquid-filled liner assembly, the liquid-filled liner assembly comprising:

an inner tubular member having a central axis;

an outer tubular member surrounding the inner tubular member in a coaxial relationship, an annular space being defined between the inner and outer tubular members; and

a tubular elastic member interposed and connected between the inner tubular member and the outer tubular member and defining first to fourth liquid chambers arranged in order at regular intervals in a circumferential direction,

the tubular elastic member defines a first communication passage that communicates the first liquid chamber with the third liquid chamber, a second communication passage that communicates the second liquid chamber with the fourth liquid chamber, a third communication passage that communicates the first liquid chamber with the second liquid chamber, and a fourth communication passage that communicates the third liquid chamber with the fourth liquid chamber,

wherein the first liquid chamber, the second liquid chamber, the third liquid chamber, the fourth liquid chamber, the first communicating channel, the second communicating channel, the third communicating channel, and the fourth communicating channel are filled with a viscous fluid,

wherein the liquid chambers are configured such that when the inner tubular member is moved along the central axis relative to the outer tubular member, the cubic volume of the first liquid chamber and the cubic volume of the second liquid chamber change in a mutually complementary manner, and the cubic volume of the third liquid chamber and the cubic volume of the fourth liquid chamber change in a mutually complementary manner,

when the inner tubular member is rotated about the central axis relative to the outer tubular member, the cubic volumes of the first and second liquid chambers change in a mutually complementary manner, and the cubic volume of the third and fourth liquid chambers change in a mutually complementary manner,

when the inner tubular member is moved relative to the outer tubular member in the arrangement direction of the first liquid chamber and the third liquid chamber, the cubic volume of the first liquid chamber and the cubic volume of the third liquid chamber change in a mutually complementary manner, and

when the inner tubular member is moved relative to the outer tubular member in the arrangement direction of the second liquid chamber and the fourth liquid chamber, the cubic volume of the second liquid chamber and the cubic volume of the fourth liquid chamber change in a mutually complementary manner.

2. The liquid-filled liner assembly of claim 1, wherein the tubular resilient member is provided with: first to fourth radial walls extending in a radial direction with respect to the central axis and arranged in order about the central axis; four first end wall portions attached to respective first axial ends of the radial walls; and four second endwall portions attached to respective second axial ends of the radial walls such that the first through fourth liquid chambers are defined by the first through fourth radial walls, the four first endwall portions, and the four second endwall portions.

3. The liquid-filled liner assembly of claim 2, wherein a high bending stiffness portion is provided radially inward of the first endwall portion defining a first axial end of the first liquid chamber and radially inward of the second endwall portion defining a second axial end of the second liquid chamber, and another high bending stiffness portion is provided radially outward of the second endwall portion defining a second axial end of the first liquid chamber and radially outward of the first endwall portion defining a first axial end of the second liquid chamber.

4. The liquid-filled liner assembly of claim 3, wherein the high bending stiffness portion comprises a reinforcement plate disposed in each respective end wall portion.

5. The liquid-filled liner assembly of claim 2, wherein a high bending stiffness portion is provided in a radially inner portion of the first and third radial walls and another high bending stiffness portion is provided in a radially outer portion of the second and fourth radial outer walls.

6. The liquid-filled liner assembly of claim 5, wherein the high bending stiffness portion comprises a reinforcement plate disposed in each respective radial wall.

7. The liquid-filled liner assembly of claim 1, wherein the outer tubular member comprises: a coil disposed in a coaxial relationship with the inner tubular member; and a yoke having an axial gap inside the coil; and the viscous fluid is composed of a magnetic fluid whose viscosity is increased by a magnetic field, at least one of the communication passages extending through the axial gap.

8. The liquid-filled bushing assembly of claim 7, wherein said outer tubular member further includes a channel-forming member made of a material having low magnetic permeability and surrounding said axial gap from radially inward thereof to define said at least one of said communication channels extending through said axial gap in cooperation with said coil and said yoke.

9. The liquid-filled liner assembly of claim 7, wherein the coil includes a first coil, a second coil, and a third coil arranged in spaced relation to one another along the central axis, and the yoke defines first to third axial gaps that serve as magnetic gaps that correspond to the first to third coils, respectively, and

wherein the first communication passage passes through the first axial gap, the second communication passage passes through the second axial gap, and the third communication passage passes through the third axial gap.

Technical Field

The present disclosure relates to a liquid-filled bushing assembly configured to be interposed between a vibration source and a support member supporting the vibration source, and more particularly, to a liquid-filled bushing assembly capable of varying stiffness.

Background

A conventional liquid-filled liner assembly includes: an inner tubular member; an outer tubular member coaxially provided to the inner tubular member; and a plurality of elastic partition wall members extending radially between the inner and outer tubular members to define a plurality of liquid chambers communicating with each other via the orifice passage. The liquid chamber and the orifice passage are filled with a liquid. See, for example, JP2002-310219 a. According to this prior art, the liquid-filled liner assembly is provided with three pairs of liquid chambers which are circumferentially arranged at regular intervals, and each pair of diametrically opposed liquid chambers communicate with each other via an orifice passage.

When the liquid-filled liner is subjected to vibration along one of a pair of liquid chambers opposed to each other, a damping force against the vibration is generated due to the movement of the liquid between the two liquid chambers. By appropriately configuring the respective orifice channels and selecting various other parameters, the damping action can be appropriately tuned to the target frequency. This particular liquid-filled liner can be tuned to dampen vibrations at three different frequencies due to the presence of three pairs of liquid chambers.

There are often situations where a liquid-filled liner assembly is required to be able to dampen vibrations not only in the radial direction but also in the axial and rotational directions. Accordingly, it is desirable for the liquid-filled liner assembly to be able to dampen vibrations in a desired direction, and for the stiffness of the liquid-filled liner assembly to be variable or selectable in various directions according to each particular need.

Disclosure of Invention

In view of such problems of the prior art, it is a primary object of the present invention to provide a liquid-filled liner assembly including an inner tubular member; an outer tubular member disposed in a coaxial relationship with the inner tubular member; and an elastic member interposed between the inner and outer tubular members, wherein not only a rigidity of the liquid-filled liner assembly in the lateral direction but also a rigidity of the liquid-filled liner assembly in the rotational direction and/or the axial direction can be freely selected.

To achieve such an object, the present invention provides a liquid-filled liner assembly (1) comprising: an inner tubular member (11) having a central axis (X); an outer tubular member (12) surrounding the inner tubular member in a coaxial relationship and defining an annular space therebetween; and a tubular elastic member (13) interposed and connected between the inner and outer tubular members and defining first to fourth liquid chambers (21) arranged in order at regular intervals in a circumferential direction, the tubular elastic member defining a first communication passage (42A) communicating the first liquid chamber (21A) with the third liquid chamber (21C), a second communication passage (42B) communicating the second liquid chamber (21B) with the fourth liquid chamber (21D), a third communication passage (42C) communicating the first liquid chamber (21A) with the second liquid chamber (21B), and a fourth communication passage (42D) communicating the third liquid chamber (21C) with the fourth liquid chamber (21D), wherein the first liquid chamber, the second liquid chamber, the third liquid chamber (21C), and the fourth liquid chamber (21D) are arranged in this order, and wherein the first liquid chamber, the second liquid chamber, the fourth liquid chamber, the third liquid chamber, and the fourth liquid chamber (21D) are arranged in this order, The third, fourth, first, second, third, and fourth liquid chambers are filled with a viscous fluid (70), wherein the liquid chambers are configured such that when the inner tubular member is moved along the central axis relative to the outer tubular member, the cubic volumes of the first and second liquid chambers change in a mutually complementary manner, and the cubic volumes of the third and fourth liquid chambers change in a mutually complementary manner; the cubic volumes of the first and second liquid chambers vary in a mutually complementary manner and the cubic volumes of the third and fourth liquid chambers vary in a mutually complementary manner when the inner tubular member is rotated about the central axis relative to the outer tubular member; when the inner tubular member is moved relative to the outer tubular member in the arrangement direction of the first liquid chamber and the third liquid chamber, cubic volumes of the first liquid chamber and the third liquid chamber change in a mutually complementary manner; and cubic volumes of the second liquid chamber and the fourth liquid chamber change in a mutually complementary manner when the inner tubular member is moved relative to the outer tubular member in an arrangement direction of the second liquid chamber and the fourth liquid chamber.

According to this configuration, when a load is applied to the inner tubular member with respect to the outer tubular member in the arrangement direction of the first liquid chamber and the third liquid chamber, the viscous fluid flowing through the first communication passage that communicates the first liquid chamber and the third liquid chamber with each other encounters a certain flow resistance. When a load is applied to the inner tubular member with respect to the outer tubular member in the arrangement direction of the second liquid chamber and the fourth liquid chamber, the viscous fluid flowing through the second communication passage that communicates the second liquid chamber and the fourth liquid chamber with each other encounters a certain flow resistance. Therefore, by changing the cross-sectional areas and the lengths of the first and second communication passages, the rigidity of the liquid-filled liner assembly in the two directions orthogonal to the axis (the arrangement direction of the first and third liquid chambers and the arrangement direction of the second and fourth liquid chambers) can be changed.

Further, when a load is applied to the inner tubular member relative to the outer tubular member in a direction parallel to the axis or a direction in which the inner tubular member is rotated relative to the outer tubular member about the axis, the viscous fluid flowing through the third communication passage that communicates the first liquid chamber and the second liquid chamber with each other encounters a certain flow resistance, and the viscous fluid flowing through the fourth communication passage that communicates the third liquid chamber and the fourth liquid chamber with each other encounters a certain flow resistance. Therefore, by changing the cross-sectional areas and lengths of the third communication passage and the fourth communication passage, the rigidity of the liquid-filled liner assembly in both directions (the direction parallel to the axis and the direction of rotating the inner tubular member) can be changed.

Preferably, the tubular elastic member is provided with: first to fourth radial walls (18, 18) extending in a radial direction with respect to the central axis and arranged in sequence around the central axis; four first end wall portions (19) attached to respective first axial ends of the radial walls; and four second endwall portions (20) attached to respective second axial ends of the radial walls such that the first to fourth liquid chambers are defined by the first to fourth radial walls, the four first endwall portions, and the four second endwall portions.

Thereby, four liquid chambers arranged in the circumferential direction can be formed in the elastic member by using a simple structure.

Preferably, a high bending rigidity portion (22A, 22B) is provided radially inward of the first endwall portion defining a first axial end of the first liquid chamber and radially inward of the second endwall portion defining a second axial end of the second liquid chamber, and another high bending rigidity portion (32A, 32B) is provided radially outward of the second endwall portion defining a second axial end of the first liquid chamber and radially outward of the first endwall portion defining a first axial end of the second liquid chamber.

Thus, when the inner tubular member is moved in an upward direction relative to the outer tubular member, the cubic volume of the first liquid chamber can be increased, while the cubic volume of the second liquid chamber is decreased. In contrast, when the inner tubular member is moved in a downward direction relative to the outer tubular member, the cubic volume of the first liquid chamber can be decreased, while the cubic volume of the second liquid chamber is increased. Thus, the cubic volumes of the first and second liquid chambers can be changed in a mutually complementary manner in response to vertical movement of the inner tubular member relative to the outer tubular member.

The high bending rigidity portion may include a reinforcing plate (16B, 16C, 27, 28) provided in each of the respective end wall portions, so that the high bending rigidity portion can be formed by using a simple structure.

Preferably, a high bending stiffness portion (22C) is provided in a radially inner portion of the first and third radial walls, and another high bending stiffness portion (32C) is provided in a radially outer portion of the second and fourth radial walls.

Thus, when the inner tubular member is rotated relative to the outer tubular member, the cubic volume of one of the diagonally opposed pair of liquid chambers increases, while the cubic volume of the other of the diagonally opposed pair of liquid chambers decreases. In other words, the cubic volume of one of the diagonally opposed pair of liquid chambers varies in a mutually complementary manner with respect to the cubic volume of the other of the diagonally opposed pair of liquid chambers.

The high bending stiffness portion may include a stiffening plate (16A, 26E) disposed in each respective radial wall.

Preferably, the outer tubular member comprises: a coil (40) disposed coaxially with the inner tubular member; and a yoke (45, 47) having an axial gap (60) located inside the coil; and the viscous fluid is composed of a magnetic fluid whose viscosity is increased by a magnetic field, at least one of the communication passages extending through the axial gap.

By energizing the coil, the viscosity of the viscous fluid flowing through the communication passage defined in the axial gap can be increased. Thereby, the flow resistance to the viscous fluid flowing through the communication passage can be increased, so that the rigidity of the liquid-filled liner assembly can be increased as required.

Preferably, the outer tubular member further comprises a channel forming member (46) made of a material having low magnetic permeability and surrounding the axial gap from a radially inner side thereof to define, in cooperation with the coil and the yoke, the at least one of the communication channels extending through the axial gap.

Therefore, the communication passage can be formed in a good manner without disturbing or disturbing the magnetic circuit formed by the yoke.

Preferably, the coil includes a first coil (40A), a second coil (40B), and a third coil (40C) arranged in a spaced-apart relationship from each other along the central axis, and the yoke defines first to third axial gaps serving as magnetic gaps corresponding to the first to third coils, respectively, and wherein the first communication passage passes through the first axial gap (60A), the second communication passage passes through the second axial gap (60B), and the third communication passage passes through the third axial gap (60C).

According to this configuration, by exciting the first coil, the viscosity of the viscous fluid in the first communicating channel can be increased. This hinders the movement of the viscous fluid between the first liquid chamber and the third liquid chamber, and increases the resistance to the movement of the inner tubular member in the arrangement direction of the first liquid chamber and the third liquid chamber. Similarly, by energizing the second coil, it is possible to increase the resistance to the movement of the inner tubular member in the arrangement direction of the second liquid chamber and the fourth liquid chamber.

Further, by energizing the third coil, the viscosity of the viscous fluid passing through the third gap in the third communication passage and the fourth communication passage can be increased. Therefore, resistance to movement of the viscous fluid flowing between the first liquid chamber and the second liquid chamber and resistance to movement of the viscous fluid flowing between the third liquid chamber and the fourth liquid chamber are increased. This increases the force required to move the inner tubular member in a direction parallel to the axis and increases the force or torque required to rotate the inner tubular member about the axis. Thus, by exciting the first coil, the second coil, and the third coil, respectively, it is possible to change the rigidity against the load for moving the inner tubular member relative to the outer tubular member in the two directions orthogonal to the axis, the direction parallel to the axis, and the rotational direction about the axis.

Accordingly, the present invention provides a liquid-filled liner assembly comprising an inner tubular member; an outer tubular member disposed in a coaxial relationship with the inner tubular member; and an elastic member interposed between the inner and outer tubular members, wherein not only a rigidity of the liquid-filled liner assembly in the lateral direction but also a rigidity of the liquid-filled liner assembly in the rotational direction and/or the axial direction can be freely selected.

Drawings

FIG. 1 is a schematic perspective view of a liquid filled bushing assembly according to one embodiment of the present invention as mounted to a lower arm of a wheel suspension;

FIG. 2 is an exploded perspective view of the liquid-filled liner assembly;

FIG. 3A is a cross-sectional view taken along line IIIA-IIIA of FIG. 1;

FIG. 3B is a cross-sectional view taken along line IIIB-IIIB of FIG. 1;

FIG. 3C is a cross-sectional view taken along line IIIC-IIIC of FIG. 1;

FIG. 4A is a cross-sectional view taken along line IVA-IVA of FIG. 3A;

FIG. 4B is a cross-sectional view taken along line IVB-IVB of FIG. 3A;

FIG. 4C is a cross-sectional view taken along line IVC-IVC of FIG. 3A;

FIG. 5 is a view similar to FIG. 4A, illustrating the movement of the viscous fluid as the inner tubular member moves in a fore-aft direction relative to the outer tubular member;

FIG. 6 is a view similar to FIG. 4C, illustrating the movement of the viscous fluid as the inner tubular member moves in a transverse direction relative to the outer tubular member;

FIG. 7A is a cross-sectional view of the front liquid chamber as the inner tubular member moves upwardly relative to the outer tubular member;

FIG. 7B is a cross-sectional view of the right liquid chamber as the inner tubular member moves upward relative to the outer tubular member;

FIG. 7C is a cross-sectional view of the front liquid chamber as the inner tubular member moves downward relative to the outer tubular member;

FIG. 7D is a cross-sectional view of the right liquid chamber as the inner tubular member moves downward relative to the outer tubular member;

FIG. 8A is a view similar to FIG. 4B when the inner tubular member is rotated counterclockwise relative to the outer tubular member in top view;

FIG. 8B is a view similar to FIG. 4B when the inner tubular member is rotated clockwise relative to the outer tubular member in top view;

FIG. 9 is a vertical cross-sectional view showing the magnetic field generated by the coil when current is supplied to the coil; and

fig. 10 is a view similar to fig. 9 showing a modified embodiment of the present invention.

Detailed Description

A liquid-filled liner assembly 1 according to a first embodiment of the present invention will now be described with reference to the accompanying drawings.

The liquid-filled bush assembly 1 according to the embodiment of the present invention is provided in, for example, the lower arm 2 of a double wishbone type wheel suspension device for connecting a knuckle (not shown in the drawings) supporting a rear wheel to a vehicle body.

The lower arm 2 is a metal member that extends in the lateral direction of the vehicle body, and is connected to the knuckle at its outboard end and to the vehicle body at its inboard end. As shown in fig. 1, the inner end of the lower arm 2 is provided with a through hole passing in the vertical direction, in which the liquid-filled bushing assembly 1 is fitted. The liquid-filled liner assembly 1 has a cylindrical shape and is attached to the lower wall 2 in such a way that its axis X extends in a vertical direction. The liquid-filled bushing assembly 1 is provided with a bolt hole 5 extending centrally along the axis X, and a bolt passing through the bolt hole 5 is fastened to the vehicle body so that the inner end of the lower arm 2 is connected to the vehicle body. The various directions mentioned in the following disclosure are based on the assumption that the liquid-filled bushing assembly 1 is provided at the inboard end of the lower arm, but the present invention is not limited to this embodiment and the orientation of the axis X may also be freely selected according to each particular application.

The liquid-filled liner assembly 1 comprises: a cylindrical inner tubular member 11; a cylindrical outer tubular member 12 coaxially surrounding the inner tubular member 11 and defining a certain annular space therebetween; and an elastic member 13 interposed and connected between the inner tubular member 11 and the outer tubular member 12.

The inner tubular member 11 is a metal member, more specifically, a metal (e.g., aluminum) member having low magnetic permeability, or the like. In the present embodiment, the inner tubular member 11 extends in the vertical direction along the axis X, and includes: a cylindrical inner tubular body 15 extending along an axis X and defining a bolt hole 5; and an inner reinforcement portion 16 made of a bent plate member protruding radially outward from the inner tubular body 15.

As shown in fig. 2, the inner reinforcement portion 16 includes: a pair of intermediate inner reinforcing plates 16A that project radially outward at diametrically opposite positions and extend vertically from an upper portion to a lower portion of the outer peripheral surface of the inner tubular body 15; a pair of upper inner reinforcing plates 16B that project radially outward and extend in the circumferential direction; and a pair of lower inner reinforcing plates 16C that project radially outward and extend in the circumferential direction.

The intermediate inner stiffening plates 16A project away from each other in diametrically opposite directions with respect to the axis X. More specifically, one of the intermediate inner reinforcement plates 16A protrudes in the right front direction, and the other intermediate inner reinforcement plate 16A protrudes in the left rear direction.

Each of the upper inner reinforcement plates 16B faces the vertical direction and has a fan shape spanning an angle slightly less than 90 degrees in plan view, and one of the upper inner reinforcement plates 16B extends in the forward direction while the other upper inner reinforcement plate 16B extends in the leftward direction. The two upper inner reinforcement plates 16B extend at the same height and are circumferentially spaced from each other by a gap or recess defined therebetween.

The right edge of the upper inner reinforcement plate 16B projecting forward may be connected to the upper edge of the middle inner reinforcement plate 16A projecting rightward and forward, and the rear edge of the upper inner reinforcement plate 16B projecting leftward may be connected to the upper edge of the middle inner reinforcement plate 16A projecting leftward and rearward.

Each lower inner reinforcement plate 16C faces the vertical direction and has a fan shape in plan view that spans an angle slightly less than 90 degrees, and one of the lower inner reinforcement plates 16C extends in the rearward direction while the other lower inner reinforcement plate 16C extends in the rightward direction. The two lower inner stiffening webs 16C extend at the same height and are circumferentially spaced from each other by a gap or recess defined therebetween.

The left edge of the lower inner reinforcement plate 16C extending rearward may be connected to the lower edge of the middle inner reinforcement plate 16A projecting in the left rear direction, and the front edge of the lower inner reinforcement plate 16C extending rightward may be connected to the lower edge of the middle inner reinforcement plate 16A projecting in the right front direction.

The elastic member 13 is made of an elastic material such as rubber or elastomer. The elastic member 13 includes: a cylindrical central body 17 disposed in a coaxial relationship around the outer peripheral surface of the inner tubular member 11; and first to fourth radial walls 18 extending radially outward from the outer peripheral surface of the center body 17. The elastic member 13 further includes: an upper end wall 19 (first end wall) extending radially outward from an upper end of the center body 17; and a lower end wall 20 (second end wall 20) extending radially outward from the lower end of the center body 17.

Each radial wall 18 extends vertically from an upper end to a lower end of the central body 17 and has a plate shape facing the circumferential direction. Each radial wall 18 is connected at its radially outer end to the inner peripheral surface of the outer tubular member 12. In plan view, the first to fourth radial walls 18 are indicated with suffixes a to D according to the clockwise circumferential order in which they are arranged. The first radial wall 18 (right front wall 18A) projects rightward and forward from the outer peripheral surface of the center body 17, and the second radial wall 18 (right rear wall 18B) projects rightward and rearward from the outer peripheral surface of the center body 17. The third radial wall 18 (left rear wall 18C) projects leftward and rearward from the outer peripheral surface of the center body 17, and the fourth radial wall 18 (left front wall 18D) projects leftward and forward from the outer peripheral surface of the center body 17.

The upper end wall 19 has a disk shape and faces in the vertical direction. The upper end wall 19 is connected to the outer peripheral surface of the central body 17, the upper edge of the radial wall 18, and the inner peripheral surface of the outer tubular member 12.

More specifically, the upper end wall 19 can be considered to be made up of four sectors 19A to 19D, each spanning an angle of about 90 degrees and connected to the upper edge of the corresponding adjacent radial wall 18. More specifically, the front sectorial portion 19A of the upper end wall 19 is connected to the outer peripheral surface of the central body 17, the upper end of the left front wall 18D, the upper end of the right front wall 18A, and the inner peripheral surface of the outer tubular member 12. The right scallop 19B of the upper end wall 19 is connected to the outer peripheral surface of the center body 17, the upper end of the right front wall 18A, the upper end of the right rear wall 18B, and the inner peripheral surface of the outer tubular member 12. The rear sectorial portion 19C of the upper end wall 19 is connected to the outer peripheral surface of the central body 17, the upper end of the right rear wall 18B, the upper end of the left rear wall 18C, and the inner peripheral surface of the outer tubular member 12. The left sectorial portion 19D of the upper end wall 19 is connected to the outer peripheral surface of the central body 17, the upper end of the left rear wall 18C, the upper end of the left front wall 18D, and the inner peripheral surface of the outer tubular member 12.

The lower end wall 20 also has a disc shape and faces in the vertical direction. The lower end wall 20 is connected to the outer peripheral surface of the central body 17, the lower edge of the radial wall 18, and the inner peripheral surface of the outer tubular member 12.

More specifically, the lower end wall 20 can also be considered to be made up of four sectors 20A to 20D, each spanning an angle of about 90 degrees and connected to the lower edge of the corresponding adjacent radial wall 18. The front sectorial portion 20A of the lower end wall 20 is connected to the outer peripheral surface of the central body 17, the lower end of the left front wall 18D, the lower end of the right front wall 18A, and the inner peripheral surface of the outer tubular member 12. The right sectorial portion 20B of the lower end wall 20 is connected to the outer peripheral surface of the central body 17, the lower end of the right front wall 18A, the lower end of the right rear wall 18B, and the inner peripheral surface of the outer tubular member 12. The rear sector portion 20C of the lower end wall 20 is connected to the outer peripheral surface of the center body 17, the lower end of the right rear wall 18B, the lower end of the left rear wall 18C, and the inner peripheral surface of the outer tubular member 12. The left sectorial portion 20D of the lower end wall 20 is connected to the outer peripheral surface of the central body 17, the lower end of the left rear wall 18C, the lower end of the left front wall 18D and the inner peripheral surface of the outer tubular member 12.

Thus, as shown in fig. 4A, an annular space defined by the outer peripheral surface of the center body 17, the inner peripheral surface of the outer tubular member 12, the upper end wall 19, and the lower end wall 20 is divided into four liquid chambers 21. These liquid chambers may be referred to as first to fourth liquid chambers 21 in clockwise order in plan view. Therefore, the four liquid chambers 21 can be arranged in the circumferential direction in a very simple manner.

More specifically, the first liquid chamber 21A (front liquid chamber 21A) is defined by the front sectorial portion 19A of the upper end wall 19, the left front wall 18D, the right front wall 18A, the front sectorial portion 20A of the lower end wall 20, and the inner peripheral surface of the outer tubular member 12. The second liquid chamber 21B (right liquid chamber 21B) is defined by the right sectorial portion 19B of the upper end wall 19, the right front wall 18A, the right rear wall 18B, the right sectorial portion 20B of the lower end wall 20, and the inner peripheral surface of the outer tubular member 12. The third liquid chamber 21C (rear liquid chamber 21C) is defined by the rear fan-shaped portion 19C of the upper end wall 19, the right rear wall 18B, the left rear wall 18C, the rear fan-shaped portion 19C of the lower end wall, and the inner peripheral surface of the outer tubular member 12. The fourth liquid chamber 21D (left liquid chamber 21D) is formed by the left fan-shaped portion 19D of the upper end wall 19, the left rear wall 18C, the left front wall 18D, the left fan-shaped portion 20D of the lower end wall 20, and the inner peripheral surface of the outer tubular member 12.

The front liquid chamber 21A and the rear liquid chamber 21C are diametrically opposed to each other via the axis X, and thus are paired in the front-rear direction. The left liquid chamber 21D and the right liquid chamber 21B are diametrically opposed to each other via the axis X, and thus are paired in the lateral direction. When no load is applied to the liquid-filled liner assembly 1, the cubic volumes of the four liquid chambers 21 are substantially equal to each other.

As shown in fig. 2, the upper inner reinforcement plate 16B abuts against the upper sides of the front and left sectorial portions 19A and 19D of the upper end wall 19 (first end wall), respectively. The outer diameter of the upper inner reinforcement plate 16B is slightly smaller than the outer diameter of the upper end wall 19, so that the radially inner portions of the front and left sectorial portions 19A and 19D of the upper end wall 19 are reinforced by the upper inner reinforcement plate 16B, respectively. The upper edge of the left front wall 18D fits closely in the gap or recess formed between the two upper inner reinforcement plates 16B. Therefore, the front sectorial portion 19A and the left sectorial portion 19D of the upper end wall 19 are provided on the radially inner portions thereof with first inner high bending rigidity portions 22A having relatively high bending rigidity (see fig. 3C).

Further, the lower inner reinforcement plate 16C abuts against the lower sides of the right and rear sectorial portions 20B and 20C of the lower end wall 20 (second end wall), respectively. The outer diameter of the lower inner reinforcement plate 16C is slightly smaller than the outer diameter of the lower end wall 20, so that the radial inner portions of the right and rear sectorial portions 20B and 20C of the lower end wall 20 are reinforced by the lower inner reinforcement plate 16C, respectively. The lower edge of the right rear wall 18B fits closely in the gap or recess formed between the two lower inner reinforcement plates 16C. Therefore, the right sectorial portion 20B and the rear sectorial portion 20C of the lower end wall 20 are provided on the radially inner portions thereof with second inner high bending rigidity portions 22B having relatively high bending rigidity (see fig. 3C).

As shown in fig. 2 and 4A, the intermediate inner reinforcement plate 16A of the inner tubular member 11 is located at positions corresponding to the right front wall 18A and the left rear wall 18C, respectively, and is embedded in the right front wall 18A and the left rear wall 18C. As a result, the radially inner portions of the right front wall 18A and the left rear wall 18C are reinforced by the respective intermediate inner reinforcement plates 16A, so that third inner high bending rigidity portions 22C having relatively high bending rigidity are provided in the radially inner portions of the right front wall 18A and the left rear wall 18C.

As shown in fig. 2, a reinforcing member 23 having a cylindrical cage shape is embedded in the elastic member 13 to increase the bending rigidity of a prescribed portion of the elastic member 13.

The reinforcing member 23 includes: an annular upper ring portion 24 provided inside the outer peripheral edge of the upper end wall 19 along the outer peripheral edge of the upper end wall 19; an annular lower ring portion 25 provided inside the outer peripheral edge of the lower end wall 20 along the outer peripheral edge of the lower end wall 20; and four vertical rods 26 (first to fourth vertical rods 26A to 26D) extending between the upper ring portion 24 and the lower ring portion 25 so as to extend along and inside the radially outer edges of the four radial walls 18, respectively. The vertical rods 26 extend vertically and are arranged at regular angular intervals along the circumferential direction. The reinforcing member 23 is made of a material having low magnetic permeability such as aluminum.

The lower ring portion 25 is provided with a lower outer reinforcement plate 27, and the lower outer reinforcement plate 27 extends radially inward over an angular range of about 180 degrees from the outer peripheral portion of the lower end wall 20 to the radially intermediate portion of the lower end wall 20 to correspond to the front sectorial portion 20A and the left sectorial portion 20D of the lower end wall 20. The lower outer reinforcement plate 27 is formed as a plate member facing the vertical direction, and is attached to the lower surface of the corresponding portion of the lower end wall 20. As a result, the front sector portion 20A and the left sector portion 20D of the lower end wall 20, which define the bottom ends of the first liquid chamber 21A and the fourth liquid chamber 21D, respectively, are formed as the first outer high bending rigidity portion 32A having a relatively high bending rigidity (see fig. 3C).

The upper ring portion 24 is provided with an upper outer reinforcement plate 28, which upper outer reinforcement plate 28 extends radially inward over an angular range of approximately 180 degrees from the outer peripheral portion of the upper end wall 19 to the radially intermediate portion of the upper end wall 20 to correspond to the right and rear sectorial portions 19B and 19C of the upper end wall 19. The upper outer reinforcement plate 28 is formed as a plate member facing in the vertical direction, and is attached to the upper surface of the corresponding portion of the upper end wall 19. As a result, the right and rear sectorial portions 19B and 19C of the upper end wall 19 defining the top ends of the second and third liquid chambers 21B and 21C, respectively, are formed as a second outer high bending rigidity portion 32B having a relatively high bending rigidity (see fig. 3C)

As shown in fig. 3A, the first to fourth vertical rods 26 each pass slightly inside the outer edge of the respective radial wall 18 and are embedded in the respective radial wall 18. More specifically, the first vertical rod 26 (right front vertical rod 26A) extends along the radially outer edge of the right front wall 18A inside the radially outer edge of the right front wall 18A. A second vertical rod 26 (right rear vertical rod 26B) extends along the radially outer edge of the right rear wall 18B inside the radially outer edge of the right rear wall 18B. A third vertical rod 26 (left rear vertical rod 26C) extends along the radially outer edge of the left rear wall 18C inwardly of the radially outer edge of the left rear wall 18C. A fourth vertical rod 26 (left front vertical rod 26D) extends vertically inside the radially outer edge of the left front wall 18D along the radially outer edge of the left front wall 18D.

As shown in fig. 2, the right rear vertical rod 26B and the left front vertical rod 26D are each provided with a radial reinforcement plate 26E, which radial reinforcement plate 26E projects radially inward from a vertically intermediate portion of the vertical rod 26 toward the center axis X. Each radial reinforcing plate 26E faces the circumferential direction and has a plate shape extending vertically. The radial stiffener plate 26E provided on the right rear vertical rod 26B is placed inside the right rear wall 18B, and the radial stiffener plate 26E provided on the left front vertical rod 26D is placed inside the left front wall 18D. As shown in fig. 4A, the radially inner edge of each radial reinforcing plate 26E reaches substantially the midpoint in the radial direction in plan view. Therefore, each radial reinforcement plate 26E is embedded in the corresponding radial wall 18, so that the right rear wall 18B and the left front wall 18D are reinforced by the radial reinforcement plate 26E, respectively. Therefore, the right rear wall 18B (second radial wall 18B) and the left front wall 18D (fourth radial wall 18D) are formed as the third outer high bending rigidity portion 32C having a relatively high bending rigidity. As discussed above, the upper ring portion 24, the lower ring portion 25 and the vertical rods 26 are incorporated in the upper end wall 19, the lower end wall 20 and the corresponding radial wall 18, respectively, to locally increase the bending stiffness of the elastic member 13. Thus, as will be discussed below, the elastic member 13 is locally and strategically reinforced to provide it with good functionality.

As shown in fig. 3A to 3C, the outer tubular member 12 includes: a coil support member 44 having a substantially cylindrical configuration; and three substantially identical helical coils 40 supported by the coil support member 44 so as to be arranged coaxially with the inner tubular member 11 along the axis X.

As shown in fig. 4A, 4B, and 4C, three coils 40 surround the four liquid chambers 21. Hereinafter, the uppermost coil 40 (first coil 40) may be referred to as an upper coil 40A, the lowermost coil 40 (second coil) may be referred to as a lower coil 40B, and the middle coil 40C (third coil 40C) may be referred to as a middle coil 40C.

As shown in fig. 2, the coil support member 44 includes: a pair of inner yokes 45 each having a cylindrical shape; a cylindrical passage forming member 46 fitted into the inner bores of the two inner yokes 45; and an outer yoke 47 surrounding the channel forming member 46, the inner yoke 45, and the three coils 40 in a coaxial relationship.

Each inner yoke 45 is a member made of a material having high magnetic permeability such as soft iron. Each inner yoke 45 includes a cylindrical tube body 49 and an annular large diameter portion 50, the annular large diameter portion 50 projecting radially outward from an axially intermediate portion of the cylindrical tube body 49 and extending circumferentially around the cylindrical tube body 49. The outer diameter of the cylindrical tubular body 49 is substantially equal to the inner diameter of the coil 40, and the outer diameter of the annular large-diameter portion 50 is substantially equal to the outer diameter of the coil 40. Hereinafter, the upper inner yoke 45 is referred to as an upper inner yoke 45A, and the lower inner yoke 45 may be referred to as a lower inner yoke 45B.

As shown in fig. 3A, the cylindrical tube body 49 of the upper inner yoke 45A is inserted into the inner bore of the upper coil 40A at an axially upper portion thereof, and is inserted into the inner bore of the intermediate coil 40C at an axially lower portion thereof. The cylindrical tube body 49 of the upper inner yoke 45A is in contact with the inner peripheral surfaces of the upper coil 40A and the intermediate coil 40C at the outer peripheral surface thereof, so that a gap between the outer surface of the upper inner yoke 45A and the inner peripheral surface of the upper coil 40A and a gap between the outer surface of the upper inner yoke 45A and the inner peripheral surface of the intermediate coil 40C are closed. The lower end surface of the upper coil 40A and the upper end surface of the intermediate coil 40C are in contact with the respective annular shoulder surfaces of the annular large-diameter portion 50.

The cylindrical tube body 49 of the lower inner yoke 45B is inserted into the inner bore of the intermediate coil 40C at the axially upper portion thereof, and is inserted into the inner bore of the lower coil 40C at the axially lower portion thereof. The cylindrical tube 49 of the lower inner yoke 45B is in contact with the inner peripheral surfaces of the intermediate coil 40C and the lower coil 40B at the outer peripheral surfaces thereof, so that a gap between the outer surface of the lower inner yoke 45B and the inner peripheral surface of the intermediate coil 40C and a gap between the outer surface of the lower inner yoke 45B and the inner peripheral surface of the lower coil 40B are closed. The lower end surface of the intermediate coil 40C and the upper end surface of the lower coil 40B are in contact with the respective annular shoulder surfaces of the annular large-diameter portion 50.

The lower edge of the upper inner yoke 45A and the upper edge of the lower inner yoke 45B are located inside the inner bore of the center coil 40C. An annular gap is defined between a lower edge of the upper inner yoke 45A and an upper edge of the lower inner yoke 45B, so that the upper inner yoke 45A and the lower inner yoke 45B are opposed to each other via the annular gap inside the intermediate coil 40C.

The passage forming member 46 is a metal member or other member made of a material having low magnetic permeability such as aluminum. As shown in fig. 3A, the channel forming member 46 vertically penetrates into the inner bores of the upper inner yoke 45A and the lower inner yoke 45B. The channel forming member 46 and the resilient member 13 have substantially the same axial length and are vertically aligned with each other. The upper end of the passage forming member 46 is slightly higher than the upper end of the upper coil 40A, and the lower end of the passage forming member 46 is slightly lower than the lower end of the lower coil 40B.

The outer yoke 47 is a member made of a material having high magnetic permeability such as soft iron. As shown in fig. 2, the outer yoke 47 includes: a cylindrical outer yoke tube 54; an upper annular projecting portion 55A projecting radially inward from an upper end of the inner periphery of the outer yoke tube 54; and a lower annular projecting portion 55B projecting radially inward from a lower end of the inner periphery of the outer yoke tube 54. In the present embodiment, the upper annular projecting portion 55A is formed integrally with the outer yoke tube 54, while the lower annular projecting portion 55B is composed of a separate ring member that is press-fitted into the inner bore of the outer yoke tube 54. The inner diameter of the outer yoke tube 54 is substantially equal to the outer diameter of the coil 40, and the axial length of the outer yoke tube 54 is substantially equal to the axial length of the channel forming member 46. The three coils 40, the inner yoke 45, and the channel forming member 46 are inserted into the inner bore of the outer yoke 47. The upper edge of the outer yoke 47 is located at the same height as the upper edge of the passage forming member 46, and the lower edge of the outer yoke 47 is located at the same height as the lower edge of the passage forming member 46.

As shown in fig. 3A, 3B, and 3C, the upper annular projection 55A has a cylindrical shape coaxial with the outer yoke tube 54. The inner circumferential surface of the upper annular projecting portion 55A abuts against the outer circumferential surface of the upper end of the passage forming member 46, so that the gap between the inner circumferential surface of the upper annular projecting portion 55A and the upper end of the outer circumferential surface of the passage forming member 46 is closed.

The lower surface of the upper annular projecting portion 55A abuts against the upper end surface of the upper coil 40A, so that the gap between the lower surface of the upper annular projecting portion 55A and the upper surface of the upper coil 40A is closed. The lower surface of the upper annular projection 55A is vertically spaced from the upper end of the upper inner yoke 45A. As a result, an annular gap is defined by the lower surface of the upper annular projecting portion 55A, the outer peripheral surface of the upper end portion of the passage forming member 46, the inner peripheral surface of the upper end portion of the upper coil 40A, and the upper end surface of the upper inner yoke 45A. Therefore, the lower surface of the upper annular projection portion 55A is opposed to the upper end surface of the upper inner yoke 45A via a gap.

The inner circumferential surface of the lower annular projecting portion 55B abuts against the outer circumferential surface of the lower end of the passage forming member 46, so that the gap between the inner circumferential surface of the lower annular projecting portion 55B and the lower end of the outer circumferential surface of the passage forming member 46 is closed.

As shown in fig. 4A, the upper surface of the lower annular projecting portion 55B abuts against the lower end surface of the lower coil 40B, so that the gap between the upper surface of the lower annular projecting portion 55B and the lower surface of the lower coil 40B is closed. The upper surface of the lower annular projecting portion 55B is vertically spaced from the lower end of the lower inner yoke 45B. As a result, an annular gap is defined by the upper surface of the lower annular projecting portion 55B, the outer peripheral surface of the lower end portion of the passage forming member 46, the inner peripheral surface of the lower end portion of the lower coil 40B, and the lower end surface of the lower inner yoke 45B. Therefore, the upper surface of the lower annular projecting portion 55B is opposed to the lower end surface of the lower inner yoke 45B via a gap.

In other words, annular gaps are generated between the upper annular projecting portion 55A of the outer yoke 47 and the upper end of the upper inner yoke 45A, between the lower end of the upper inner yoke 45A and the upper end of the lower inner yoke 45B, and between the lower annular projecting portion 55B of the outer yoke 47 and the lower end of the lower inner yoke 45B.

As shown in fig. 2, the first to fourth ribs 58 are formed on the outer peripheral surface of the passage forming member 46 so as to project radially outward and extend in the circumferential direction.

As shown in fig. 4A, the first rib 58A is fitted in an annular gap (annular upper gap 60A) between the upper annular projecting portion 55A of the outer yoke 47 and the upper end of the upper inner yoke 45A. The first rib 58A contacts the upper surface of the upper annular projection 55A of the outer yoke 47 and the upper end of the upper inner yoke 45A. The outer circumferential surface of the first rib 58A contacts the inner circumferential surface of the upper coil 40A.

The first rib 58A extends circumferentially in an angular range of substantially less than 180 degrees to reach a part of the front liquid chamber 21A and the rear liquid chamber 21C when viewed from above. Therefore, the arc-shaped first circumferential channel 62A is formed to extend along the entire circumference of the left liquid chamber 21D and a part of the front and rear liquid chambers 21A and 21C.

One end of the first rib 58A is located radially outward of the front liquid chamber 21A, and the other end of the first rib 58A is located radially outward of the rear liquid chamber 21C. The passage forming member 46 is provided at portions thereof adjacent to the circumferential ends of the first ribs 58A with first openings 64A that pass through in the radial direction, respectively, so that the front liquid chamber 21A communicates with the first circumferential passage 62A via one of the first openings 64A, and the rear liquid chamber 21C communicates with the first circumferential passage 62A via the other first opening 64A. Thus, the outer tubular member 12 is formed with the first communication passage 42 (front-rear communication passage 42A) including the first opening 64A and the first circumferential passage 62A. In other words, the first communication passage 42 is defined by a portion of the annular upper gap 60A that spans an angle substantially greater than 180 degrees to communicate the front liquid chamber 21A (the first liquid chamber 21A) with the rear liquid chamber 21C (the third liquid chamber 21C) along the outer periphery of the right liquid chamber 21B (the second liquid chamber 21B).

As shown in fig. 4C, the second rib 58B is fitted in an annular gap (annular lower gap 60B) between the lower annular projecting portion 55B of the outer yoke 47 and the lower end of the lower inner yoke 45B. The second rib 58B contacts the upper surface of the lower annular projection 55B of the outer yoke 47 and the lower end of the lower inner yoke 45B. The outer circumferential surface of the second rib 58B contacts the inner circumferential surface of the lower coil 40B.

The second rib 58B extends circumferentially in an angular range of substantially less than 180 degrees to reach a part of the left and right liquid chambers 21D and 21B when viewed from above. Therefore, the arc-shaped second circumferential channel 62B is formed to extend along the entire circumference of the front liquid chamber 21A and a part of the left and right liquid chambers 21D and 21B.

One end of the second rib 58B is located radially outward of the right liquid chamber 21B, and the other end of the second rib 58B is located radially outward of the left liquid chamber 21D. The passage forming member 46 is provided at portions thereof adjacent to the circumferential ends of the second ribs 58B with second openings 64B that pass through in the radial direction, respectively, so that the left liquid chamber 21D communicates with the second circumferential passage 62B via one of the second openings 64B, and the right liquid chamber 21B communicates with the second circumferential passage 62B via the other second opening 64B. Therefore, the outer tubular member 12 is formed with the second communication passage 42 (the lateral communication passage 42B) including the second opening 64B and the second circumferential passage 62B. In other words, the communication passage 42 is defined by a portion of the annular lower gap 60B that spans an angle substantially greater than 180 degrees to communicate the left liquid chamber 21D (fourth liquid chamber 21D) with the right liquid chamber 21B (second liquid chamber 21B) along the outer periphery of the rear liquid chamber 21C (third liquid chamber 21C).

As shown in fig. 4B, the third rib 58C and the fourth rib 58D are fitted in an annular gap (intermediate gap 60C) between the lower end of the upper inner yoke 45A and the upper end of the lower inner yoke 45B. The lower surfaces of the third and fourth ribs 58C, 58D contact the lower end of the upper inner yoke 45A, and the upper surfaces of the third and fourth ribs 58C, 58D contact the upper end of the lower inner yoke 45B. The third rib 58C abuts against the inner peripheral surface of the intermediate coil 40C, and the inner peripheral surface of the passage forming member 46 is in contact with the radially outer end of the left front wall 18D, so that the portion of the intermediate gap 60C where the third rib 58C exists is closed from the radial and axial directions. The fourth rib 58D abuts against the inner peripheral surface of the intermediate coil 40C, and the inner peripheral surface of the passage forming member 46 is in contact with the radially outer end of the right rear wall 18B, so that the portion of the intermediate gap 60C where the fourth rib 58D exists is closed from the radial and axial directions. Therefore, the opening portion of the lower gap 60B defines a fourth circumferential channel 62D that extends from the radially outer portion of the front liquid chamber 21A to the radially outer portion of the right liquid chamber 21B and from the radially outer portion of the rear liquid chamber 21C to the radially outer portion of the left liquid chamber 21D, and two sections of the fourth circumferential channel 62D respectively span angles substantially smaller than 90 degrees.

The passage forming member 46 is provided at a portion thereof adjacent to the circumferential end portion of the third rib 58C (a portion where the third rib 58C is not present) and at a portion thereof adjacent to the circumferential end portion of the fourth rib 58D (a portion where the fourth rib 58D is not present) with a third opening 66 passing through in the radial direction. More specifically, the third opening 66 includes: a front third opening 66A that communicates the front liquid chamber 21A with the intermediate gap 60C; a right third opening 66B that communicates the right liquid chamber 21B with the intermediate gap 60C; a rear third opening 66C that communicates the rear liquid chamber 21C with the intermediate gap 60C; and a left third opening 66D that communicates the left liquid chamber 21D with the intermediate gap 60C.

The front liquid chamber 21A communicates with the third circumferential channel 62C via the front third opening 66A, and the right liquid chamber 21B also communicates with the third circumferential channel 62C via the right third opening 66B. In other words, the outer tubular member 12 is provided with the third communication passage 42 (right front communication passage 42C), the third communication passage 42 being formed by the front third opening 66A, the right third opening 66B, and the third circumferential passage 62C in common, so that the front liquid chamber 21A (first liquid chamber 21) communicates with the right liquid chamber 21B (second liquid chamber 21) via the intermediate gap 60C.

The rear liquid chamber 21C communicates with the fourth circumferential channel 62D via the rear third opening 66C, and the left liquid chamber 21D also communicates with the fourth circumferential channel 62D via the left third opening 66D. In other words, the outer tubular member 12 is provided with the fourth communication passage 42 (left rear communication passage 42D), and this fourth communication passage 42 is formed by the rear third opening 66C, the left third opening 66D, and the fourth circumferential passage 62D in common, so that the rear liquid chamber 21C (third liquid chamber 21) communicates with the left liquid chamber 21D (fourth liquid chamber 21) via the intermediate gap 60C.

In other words, the channel forming member 46 surrounds the upper gap 60A, the middle gap 60C, and the lower gap 60B from the radially inner side, and defines the first to fourth communication channels 42 in cooperation with the inner yoke 45 and the outer yoke 47.

The front liquid chamber 21A, the right liquid chamber 21B, the rear liquid chamber 21C, the left liquid chamber 21D, and the first to fourth communication passages 42 are filled with a viscous fluid 70. In the present embodiment, the viscous fluid 70 is composed of a magnetic fluid whose viscosity is increased by a magnetic field. The magnetic fluid may be an incompressible fluid containing fine particles of magnetic particles dispersed in a solvent such as oil, and may be referred to as MRF (magnetorheological fluid) or MRC (magnetorheological compound). When a magnetic field is applied to the magnetic fluid, the fine particles of the magnetic material are arranged in a chain shape along the direction of the magnetic field to form chain clusters. As a result, the chain clusters hinder the flow of the solvent in the direction perpendicular to the magnetic field, so that the viscosity of the magnetic fluid increases, and the magnetic fluid may even become substantially solid.

In this embodiment, the three coils 40 are connected to a voltage source such that the voltage applied to the coils 40 can be varied and the magnetic fields generated by the coils 40 are directed in the same direction.

The mode of operation and various features of the liquid-filled liner assembly 1 constructed as described above are discussed below.

As shown in fig. 5, when a load is applied to the inner tubular member 11 in the front-rear direction, the cubic volumes of the front liquid chamber 21A and the rear liquid chamber 21C change in a complementary manner to each other (the cubic volume of one liquid chamber 21 increases, and the cubic volume of the other liquid chamber 21 decreases by a corresponding amount). As a result, the viscous fluid 70 moves between the front liquid chamber 21A and the rear liquid chamber 21C via the front-rear communication passage 42A. When the viscous fluid 70 passes through the front-rear communication passage 42A, viscous resistance is applied to the viscous fluid 70, so that resistance against the front-rear movement is applied to the inner tubular member 11. By changing the cross-sectional area and the length of the front-rear communication passage 42A, it is possible to change the magnitude of resistance against the load applied to the inner tubular member 11 in the front-rear direction or change the rigidity (elastic coefficient) in the front-rear direction. In the following disclosure, the rigidity with respect to the load that moves the inner tubular member 11 in the front-rear direction may be referred to as the rigidity in the front-rear direction of the liquid-filled liner assembly 1.

As shown in fig. 6, when a load is applied to the inner tubular member 11 in the lateral direction, the cubic volumes of the right and left liquid chambers 21B, 21D change in a manner complementary to each other (the cubic volume of one liquid chamber 21 increases, and the cubic volume of the other liquid chamber 21 decreases by a corresponding amount). As a result, the viscous fluid 70 moves between the right liquid chamber 21B and the left liquid chamber 21D via the lateral communication passage 42B. As the viscous fluid 70 passes through the lateral communication passage 42B, viscous resistance is applied to the viscous fluid 70, so that resistance against lateral movement is applied to the inner tubular member 11. By changing the cross-sectional area and the length of the lateral communication passage 42B, it is possible to change the magnitude of resistance in the lateral direction against the load applied to the inner tubular member 11 or change the rigidity (elastic coefficient) in the lateral direction. In the following disclosure, the rigidity with respect to the load that moves the inner tubular member 11 in the lateral direction may be referred to as the rigidity of the liquid-filled liner assembly 1 in the lateral direction.

As shown in fig. 7A, since the first inner high bending rigidity portion 22A is provided radially inside the front sector portion 19A, when the inner tubular member 11 is moved upward relative to the outer tubular member 12, the radially outer portion of the front sector portion 19A is bent and deformed more significantly than the radially inner portion thereof, and the radially inner portion of the front sector portion 19A is moved upward together with the inner tubular member 11 without undergoing any large deformation. At this time, since the first outer high bending stiffness portion 32A is provided in the radially outer portion of the front sector portion 20A, the radially inner portion of the front sector portion 20A is bent and deformed more significantly than the radially outer portion thereof, and the radially outer portion of the front sector portion 20A does not undergo significant deformation or movement. Therefore, due to the upward movement of the inner tubular member 11, the front sectorial portion 19A and the front sectorial portion 20A are deformed in different manners from each other, so that the cubic volume of the front liquid chamber 21A is increased (as shown by the hatched area in fig. 7A).

As shown in fig. 7B, since the second outer high bending stiffness portion 32B is provided in the radially outer portion of the right sector-shaped portion 19B, when the inner tubular member 11 is moved upward relative to the outer tubular member 12, the radially inner portion of the right sector-shaped portion 19B is bent and deformed more significantly than the radially outer portion thereof, and the radially outer portion of the right sector-shaped portion 19B does not undergo any significant deformation or movement. At this time, since the second inner high bending rigidity portion 22B is provided in the right sector portion 20B, the radially outer portion of the right sector portion 20B is bent and deformed more significantly than the radially inner portion of the right sector portion 20B, and the radially inner portion of the right sector portion 20B moves upward together with the inner tubular member 11 without undergoing substantially any deformation or movement. Therefore, due to the upward movement of the inner tubular member 11, the right sectorial portion 19B and the right sectorial portion 20B are deformed in different manners, so that the cubic volume of the right liquid chamber 21B is reduced (as shown by the hatched area in fig. 7B).

When the inner tubular member 11 moves downward relative to the outer tubular member 12, the cubic volume of the front liquid chamber 21A decreases due to the presence of the first inner high bending rigidity portion 22A and the first outer high bending rigidity portion 32A (as shown in fig. 7C). When the inner tubular member 11 moves downward relative to the outer tubular member 12, the cubic volume of the right liquid chamber 21B increases due to the presence of the second inner high bending rigidity portion 22B and the second outer high bending rigidity portion 32B (as shown in fig. 7D). In other words, when the inner tubular member 11 is moved vertically (along the axis X) relative to the outer tubular member 12, the cubic volumes of the front liquid chamber 21A (first liquid chamber 21) and the right liquid chamber 21B (second liquid chamber) change in a mutually complementary manner.

Similarly, when the inner tubular member 11 moves upward relative to the outer tubular member 12, the cubic volume of the left liquid chamber 21D increases and the cubic volume of the rear liquid chamber 21C decreases. When the inner tubular member 11 moves downward relative to the outer tubular member 12, the cubic volume of the left liquid chamber 21D decreases and the cubic volume of the rear liquid chamber 21C increases. Therefore, when the inner tubular member 11 is vertically moved relative to the outer tubular member 12, the cubic volumes of the rear liquid chamber 21C (third liquid chamber 21) and the left liquid chamber 21D (fourth liquid chamber 21) also change in a complementary manner.

As a result, when a load is applied to the inner tubular member 11 in the vertical direction, and the inner tubular member 11 is vertically moved relative to the outer tubular member 12, the viscous fluid 70 flows between the front liquid chamber 21A and the right liquid chamber 21B via the right front communication passage 42C, and flows between the rear liquid chamber 21C and the left liquid chamber 21D via the left rear communication passage 42D. Since viscous resistance is applied to the viscous fluid 70 while flowing through the communication passage 42, resistance against a load in the vertical direction is applied to the inner tubular member 11, thereby exerting a damping action on the movement of the inner tubular member 11. By changing the cross-sectional area and length of the right front communication passage 42C and the cross-sectional area and length of the left rear communication passage 42D, the magnitude of resistance against a vertical load applied to the inner tubular member 11 can be changed, and hence the rigidity (elastic coefficient) of the liquid-filled liner assembly 1 against vertical movement can be changed. In the following disclosure, the stiffness with respect to a vertical load applied to the inner tubular member 11 may be referred to as the stiffness of the liquid-filled liner assembly 1 in the vertical direction.

As shown in fig. 8A, when the inner tubular member 11 is rotated counterclockwise about the axis X with respect to the outer tubular member 12 in a plan view, both the left front wall 18D and the right rear wall 18B undergo relatively large deformation in a radially inner portion thereof than in a radially outer portion thereof due to the presence of the third outer high bending stiffness portion 32C. Meanwhile, each of the right front wall 18A and the left rear wall 18C undergoes relatively large deformation in the radially outer portion thereof than in the radially inner portion thereof, and the right front wall 18A and the left rear wall 18C move toward the front liquid chamber 21A and the rear liquid chamber 21C, respectively, as the inner tubular member 11 rotates. Therefore, when the inner tubular member 11 is rotated in the counterclockwise direction, the radial wall 18 that separates the liquid chambers 21 from each other in the circumferential direction is deformed, so that the cubic volume of the front liquid chamber 21A decreases, the cubic volume of the right liquid chamber 21B increases, the cubic volume of the rear liquid chamber 21C decreases, and the cubic volume of the left liquid chamber 21D increases.

As shown in fig. 8B, when the inner tubular member 11 is rotated clockwise about the axis X with respect to the outer tubular member 12 in a plan view, the cubic volume of the front liquid chamber 21A increases, the cubic volume of the right liquid chamber 21B decreases, the cubic volume of the rear liquid chamber 21C increases, and the cubic volume of the left liquid chamber 21D decreases. Therefore, when the inner tubular member 11 is rotated in either direction relative to the outer tubular member 12, the cubic volumes of the front liquid chamber 21A (first liquid chamber 21) and the right liquid chamber 21B (second liquid chamber 21) change in a mutually complementary manner, and the cubic volumes of the rear liquid chamber 21C (third liquid chamber 21) and the left liquid chamber 21D (fourth liquid chamber 21) change in a mutually complementary manner.

Therefore, when a load causing rotation about the axis X is applied to the inner tubular member 11, and the inner tubular member 11 is rotated relative to the outer tubular member 12, the cubic volume of two of the liquid chambers 21 along the diametrical line via the axis X increases, while the cubic volume of the remaining liquid chambers 21 decreases. More specifically, the cubic volumes of the front liquid chamber 21A and the right liquid chamber 21B are changed in a mutually complementary relationship (so that the cubic volume of the right liquid chamber 21B is decreased and the cubic volume of the front liquid chamber 21A is increased by a corresponding amount), and the cubic volumes of the rear liquid chamber 21C and the left liquid chamber 21D are changed in a mutually complementary relationship. As a result, the viscous fluid 70 moves between the front liquid chamber 21A and the right liquid chamber 21B via the right front communication passage 42C, and moves between the rear liquid chamber 21C and the left liquid chamber 21D via the left rear communication passage 42D, thereby exerting a damping action on the movement of the inner tubular member 11. By changing the cross-sectional area and length of the right front communication passage 42C and the cross-sectional area and length of the left rear communication passage 42D, it is possible to change the magnitude of resistance against a load that rotates the inner tubular member 11 or change the rigidity against rotation (torsional rigidity). In the following disclosure, the stiffness with respect to the load rotating the inner tubular member 11 may be referred to as the torsional stiffness of the liquid-filled liner assembly 1.

In this way, by changing the cross-sectional areas and lengths of the front-rear communication passage 42A, the lateral communication passage 42B, the right front communication passage 42C, and the left rear communication passage 42D, the rigidity in the front-rear direction, the rigidity in the lateral direction, the rigidity in the vertical direction, and the rigidity in the rotational direction of the liquid-filled liner assembly 1 can be changed, respectively, as desired.

Therefore, it is possible to prevent sound and vibration from being transmitted to the vehicle compartment by attenuating a prescribed vibration mode, and it is possible to increase the rigidity of the liquid-filled liner assembly 1 in a desired direction, thereby improving the drivability of the vehicle.

As shown in fig. 9, the magnetic circuits 41 formed by the upper coil 40A, the lower coil 40B, and the intermediate coil 40C, respectively, generate respective magnetic fields.

More specifically, the magnetic circuit 41A corresponding to the upper coil 40A generates a magnetic flux that forms a loop and passes through the upper annular projecting portion 55A, the outer yoke tube 54, the annular large diameter portion 50 of the upper inner yoke 45A, and the upper portion of the upper inner yoke 45A. The magnetic flux generated by the upper coil 40A substantially passes through the upper gap 60A between the upper annular protrusion 55A and the upper end of the upper inner yoke 45A. Therefore, the magnetic circuit 41A corresponding to the upper coil 40A performs a function of concentrating the magnetic field generated by the upper coil 40A in the upper gap 60A (first gap), thereby applying the magnetic field corresponding to the upper coil 40A to the first circumferential passage 62A passing through the upper gap 60A.

When a magnetic field is applied to the first circumferential passage 62A, the viscosity of the viscous fluid 70 passing through the first circumferential passage 62A increases, so that the flow of the viscous fluid 70 between the front liquid chamber 21A and the rear liquid chamber 21C is hindered. As a result, the rigidity of the liquid-filled liner assembly 1 in the front-rear direction is increased.

The magnetic circuit 41B corresponding to the lower coil 40B generates a magnetic flux that forms a loop and passes through the lower annular projecting portion 55B, the outer yoke tube 54, the annular large diameter portion 50 of the lower inner yoke 45B, and the lower portion of the lower inner yoke 45B. The magnetic flux generated by the lower coil 40B passes substantially through the lower gap 60B between the lower annular protrusion portion 55B and the lower end of the lower inner yoke 45B. Therefore, the magnetic circuit 41B corresponding to the lower coil 40B performs a function of concentrating the magnetic field generated by the lower coil 40B in the lower gap 60B (second gap), thereby applying the magnetic field corresponding to the lower coil 40B to the second circumferential passage 62B passing through the lower gap 60B.

When a magnetic field is applied to the second circumferential channel 62B, the viscosity of the viscous fluid 70 passing through the second circumferential channel 62B increases, so that the flow of the viscous fluid 70 between the right liquid chamber 21B and the left liquid chamber 21D is hindered. As a result, the rigidity of the liquid-filled liner assembly 1 in the transverse direction is increased.

The magnetic circuit 41C corresponding to the middle coil 40C generates a magnetic flux that forms a loop and passes through the lower portion of the upper inner yoke 45A, the annular large diameter portion 50 of the upper inner yoke 45A, the outer yoke tube 54, the annular large diameter portion 50 of the lower inner yoke 45B, and the upper portion of the lower inner yoke 45B. The magnetic flux generated by the middle coil 40C passes substantially through the middle gap 60C between the lower end of the upper inner yoke 45A and the upper end of the lower inner yoke 45B. Therefore, the magnetic circuit 41C corresponding to the intermediate coil 40C performs a function of concentrating the magnetic field generated by the intermediate coil 40C in the intermediate gap 60C (third gap), thereby applying the magnetic field corresponding to the intermediate coil 40C to the third circumferential passage 62C passing through the intermediate gap 60C.

When a magnetic field is applied to the third circumferential channel 62C and the fourth circumferential channel 62D, the viscosity of the viscous fluid 70 flowing through the communication channel 42 through the third circumferential channel 62C and the fourth circumferential channel 62D (in other words, the right front communication channel 42C and the left rear communication channel 42D) increases. Therefore, the movement of the viscous fluid 70 between the front liquid chamber 21A and the right liquid chamber 21B and the movement of the viscous fluid 70 between the rear liquid chamber 21C and the left liquid chamber 21D are hindered, respectively. Therefore, the rigidity in the vertical direction and the rigidity in the rotational direction of the inner tubular member 11 increase.

Therefore, the rigidity in the front-rear direction of the liquid-filled liner assembly 1 can be changed by changing the current flowing through the upper coil 40A, and the rigidity in the lateral direction of the liquid-filled liner assembly 1 can be changed by changing the current flowing through the lower coil 40B. By varying the current flowing through the intermediate coil 40C, both the vertical stiffness and the torsional stiffness of the liquid-filled liner assembly 1 can be varied. In this way, the rigidity of the liquid-filled liner assembly 1 can be increased and the drivability can be improved, for example, by increasing the magnitude of the current according to the steering angle. In addition, when driving on a highway or the like, the riding comfort can be improved by reducing the rigidity of the liquid-filled liner assembly 1 so that the noise and vibration transmitted to the vehicle compartment can be reduced. Further, by using a material having a low magnetic permeability for the passage forming member 46, the communication passage 42 can be formed without interfering with the magnetic circuit 41.

The present invention has been described according to specific embodiments, but the present invention is not limited to such embodiments and may be modified in various ways without departing from the scope of the present invention. For example, the liquid-filled liner assembly 1 of the present embodiment is provided with three coils 40, but it is also possible to provide a single coil 40 in the portions occupied by the upper coil 40A, the middle coil 40C, and the lower coil 40B of the foregoing embodiment while omitting the annular large diameter portions 50 of the upper inner yoke 45A and the lower inner yoke 45B. In this case, the rigidity of the liquid-filled liner assembly 1 in the front-rear direction, the lateral direction, the vertical direction, and the rotational direction is simultaneously changed according to the intensity of the current supplied to the coil 40.

In the above embodiment, the upper inner yoke 45A and the lower inner yoke 45B are described as being composed of different portions of a single member, but they may also be composed of a plurality of pieces, so that the assembly of the upper inner yoke 45A and the lower inner yoke 45B to the channel forming member 46 may be facilitated. In addition, with respect to the outer yoke 47, the outer yoke tube main body 54 and the upper annular projection 55A may be composed of two separate members that are joined to each other by press-fitting, welding, or any other means.

In the above embodiment, the liquid-filled liner assembly 1 is provided with the coil 40, and the magnetic fluid is used as the viscous fluid 70 to allow the rigidity thereof to be variable, but according to the broad concept of the present invention, the viscous fluid 70 may not be the magnetic fluid when the rigidity thereof is not required to be variable.

The invention applies to automobiles or any other road vehicles, but may also be applied to rail cars and aircraft. Various components of the embodiments are not entirely necessary for the present invention, and may be appropriately omitted and modified without departing from the scope of the present invention.