CN107023600B

CN107023600B - Rubber bushing for railway vehicle

Info

Publication number: CN107023600B
Application number: CN201610964241.7A
Authority: CN
Inventors: 岩田英明
Original assignee: Sumitomo Riko Co Ltd
Current assignee: Sumitomo Riko Co Ltd
Priority date: 2015-10-30
Filing date: 2016-10-28
Publication date: 2020-03-03
Anticipated expiration: 2036-10-28
Also published as: JP2017082994A; JP6585468B2; CN107023600A

Abstract

The invention provides a rubber bushing for a railway vehicle. The rubber bushing for a railway vehicle can cope with a plurality of vibration characteristics with minimum change required, and can realize sharing of components and improvement of design freedom. A rubber bush (1) for a railway vehicle comprises a shaft center member (2), an outer cylinder member (3) disposed coaxially with the shaft center member (2) on the outer side of the shaft center member (2), and a rubber elastic body (4) elastically connecting the shaft center member (2) and the outer cylinder member (3), wherein the rubber elastic body (4) has liquid chambers (9, 9) filled with fluid at a point-symmetric position with the shaft center member (2) as the center, the shaft center member (2) comprises an independent flow path member (12) having a throttle path (14) for communicating the liquid chambers (9, 9) with each other, and the vibration characteristics can be changed by replacing the flow path member (12) having a different pattern of the throttle path (14).

Description

Rubber bushing for railway vehicle

Technical Field

The present invention relates to a rubber bush for a railway vehicle interposed between, for example, a bogie frame and an axle box supporting an axle in the railway vehicle for vibration isolation.

Background

As disclosed in patent document 1, for example, a rubber bush for a railway vehicle has a structure in which: rubber is interposed between an outer tube attached to one of the bogie-side anti-deflection device and the vehicle-body-side arm and an axle bar attached to the other of the bogie-side anti-deflection device and the vehicle-body-side arm, two or more liquid chambers in which liquid is sealed are formed, and the liquid chambers are communicated with each other by a restricted passage. With this configuration, when vibration is applied to one liquid chamber, pressure change of the liquid chamber acts on the other liquid chamber through the limiting passage, and the vibration is absorbed by the passage resistance and the liquid resonance in the limiting passage. Further, patent document 2 discloses an invention in which: an inner tube is provided on one of a bogie frame side and a shaft box side supporting a wheel shaft, an outer tube is provided on the other of the bogie frame side and the shaft box side supporting the wheel shaft, an elastic body is arranged between the inner tube and the outer tube, a plurality of liquid chambers partitioned in the elastic body are communicated by a throttle passage, and a spring constant changing member such as an electromagnetic valve is provided in the throttle passage to reduce a spring constant and prevent the throttle passage from being clogged.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 6-135329

Patent document 2: japanese patent No. 3397340

Disclosure of Invention

Problems to be solved by the invention

Rubber bushings for railway vehicles are different in vibration characteristics (dynamic spring constant) required depending on the use conditions in the running section (for example, high-speed section and low-speed section). However, since the rubber bush of patent document 1 has a fixed vibration characteristic of 1, it is necessary to separately prepare a shaft rod having different sectional areas and lengths for restricting the passage in order to cope with a plurality of vibration characteristics, which leads to an increase in cost. The rubber bush of patent document 2 can change the spring constant in two steps of high and low by opening and closing the solenoid valve as the spring constant changing means, but the use of the solenoid valve still leads to an increase in cost. Further, since the electromagnetic valve is relied upon, the degree of freedom in designing the vibration characteristics is reduced because the setting is limited to two steps.

Therefore, an object of the present invention is to provide a rubber bush for a railway vehicle, which can cope with a plurality of vibration characteristics with minimum change required, and which can be expected to share components and improve the degree of freedom in design.

Means for solving the problems

In order to achieve the above object, claim 1 is a rubber bush for a railway vehicle, comprising: a shaft member; an outer cylinder member disposed coaxially with the axial member outside the axial member; and a rubber elastic body elastically connecting the axial center member and the outer cylinder member, the rubber elastic body having a liquid chamber in which a fluid is sealed at least at a point-symmetric position with respect to the axial center member,

the shaft member includes an independent flow path member having a flow path that communicates the liquid chambers with each other.

In the rubber bush for a railway vehicle according to claim 1, claim 2 is characterized in that the flow path member is a shaft body which is fitted into a through hole formed in the shaft center member and communicating the liquid chambers with each other, and the flow path is recessed in an outer periphery of the shaft body.

In the rubber bush for a railway vehicle according to claim 1, claim 3 is characterized in that the flow path member is a divided member obtained by dividing the shaft center member at a boundary with a plane which is orthogonal to the shaft center of the shaft center member and includes the liquid chamber, and the flow path is formed on a divided surface of the divided member which is the flow path member.

In the rubber bush for a railway vehicle according to claim 1, claim 4 is characterized in that the shaft center member includes an inner tube to which the rubber elastic body is connected at an outer periphery thereof, and the flow path member is a core member which is fitted in the inner tube and has a flow path formed at an outer peripheral surface thereof.

In the rubber bush for a railway vehicle according to claim 1, claim 5 is characterized in that the flow path member is a tube which is inserted into a through hole formed in the shaft center member between the liquid chambers, and ends of the tube are connected to the liquid chambers, respectively.

ADVANTAGEOUS EFFECTS OF INVENTION

In the invention according to claim 1, the shaft center member is provided with the independent flow path member having the flow path for communicating the liquid chambers with each other, so that the vibration characteristics can be changed by replacing the flow path member having a different flow path pattern. Therefore, it is possible to cope with a plurality of vibration characteristics by changing the flow path member at the minimum necessary, and it is possible to expect sharing of components and improvement of the degree of freedom in design.

In addition to the effect of claim 1, according to claim 2, the flow path member can be easily replaced by providing the flow path member as a shaft body fitted into the through hole.

In addition to the effect of claim 1, according to claim 3, the flow path member is provided as a divided member, whereby the flow path can be formed at the same time as the divided member is assembled.

In addition to the effect of claim 1, according to claim 4, the flow path member is a core member having a flow path formed on an outer peripheral surface thereof, whereby a reasonable structure is provided in which the flow path is formed simultaneously with the assembly of the core member.

In addition to the effect of claim 1, according to claim 5, the flow path member is a tube, which can be easily replaced.

Drawings

Fig. 1(a) is an explanatory view of a rubber bush for a railway vehicle according to embodiment 1, and shows a cross section.

Fig. 1(B) is an explanatory view of the rubber bush for a railway vehicle according to embodiment 1, and is a vertical cross section.

Fig. 2(a) is an explanatory view of the rubber bush for a railway vehicle according to embodiment 2, which is shown in a cross section.

Fig. 2(B) is an explanatory view of the rubber bush for a railway vehicle according to embodiment 2, which is shown in a vertical section.

Fig. 3(a) is an explanatory view of the rubber bush for a railway vehicle according to embodiment 3, which is shown in a cross section.

Fig. 3(B) is an explanatory view of the rubber bush for a railway vehicle according to embodiment 3, which is shown in a vertical section.

Fig. 4(a) is an explanatory view of the rubber bush for a railway vehicle according to embodiment 4, which is shown in a cross section.

Fig. 4(B) is an explanatory view of the rubber bush for a railway vehicle according to embodiment 4, which is shown in a vertical section.

Fig. 5(a) is an explanatory view of the rubber bush for a railway vehicle according to embodiment 5, which is shown in cross section.

Fig. 5(B) is an explanatory view of the rubber bush for a railway vehicle according to embodiment 5, which is shown in a vertical section.

Description of the reference numerals

1. 1A to 1D, rubber bushings for railway vehicles; 2. a shaft member; 3. an outer cylinder member; 4. a rubber elastomer; 5. an inner barrel; 5A, the inner part; 5B, an outer side portion; 6. a core member; 6A, 6B, a dividing member; 9. a liquid chamber; 10. a communicating hole; 11. a through hole; 12. a flow path member; 13. protruding strips; 14. 15, 19, 23, a throttle passage; 18. a groove; 21. a tube.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[ embodiment 1]

Fig. 1a and 1B are explanatory views showing an example of a rubber bush for a railway vehicle (hereinafter, simply referred to as a "rubber bush"), in which the rubber bush 1 includes a shaft center member 2, an outer cylinder member 3 coaxially disposed outside the shaft center member 2, and a rubber elastic body 4 elastically connecting the shaft center member 2 and the outer cylinder member 3, the shaft center member 2 is connected to, for example, a bogie frame of the railway vehicle, and the outer cylinder member 3 is connected to an axle box supporting an axle. In this case, the lower side of fig. 1(a) is the front.

The shaft center member 2 is formed by integrally fitting a cylindrical core member 6 inside the inner tube 5, and a pair of mounting

holes

7, 7 for mounting the shaft center member 2 to a leaf spring on the bogie frame side are bored in the core member 6. The outer cylindrical member 3 is a cylinder shorter than the axial center member 2 in the axial direction.

The rubber elastic body 4 is bonded to the outer peripheral surface of the inner tube 5 of the shaft member 2 and the inner peripheral surface of the outer tube member 3.

Reference numerals

8 and 8 denote hollow portions provided on the left and right. Further,

liquid chambers

9, 9 having a circular cross section and filled with an antifreeze (e.g., ethylene glycol) as a fluid are formed in the rubber elastic body 4 at point-symmetrical positions (front and rear positions in this case) with respect to the axial center of the axial center member 2.

Communication holes 10, 10 that open to the same diameter are formed in the inner cylinder 5 of the axial member 2 corresponding to the positions of the liquid chambers 9, and a through hole 11 that coaxially communicates with the communication holes 10, 10 is formed to have a diameter smaller than the diameter of the communication hole 10 in the front-rear direction of the core member 6. A flow path member 12 is inserted into the through hole 11, and the flow path member 12 is a shaft body formed by spirally forming a ridge 13 having an outer diameter substantially equal to an inner diameter of the through hole 11, and forms a spiral flow path orifice passage 14 which connects the communication holes 10, 10 to each other. Therefore, the antifreeze sealed in the

liquid chambers

9, 9 can move relative to each other through the orifice passage 14 and the communication holes 10, 10 at both ends thereof.

In the rubber bush 1 configured as described above, the axial center member 2 is coupled to the truck frame, the outer cylinder member 3 is coupled to the axle box, and vibration generated in the truck frame and the axle box is damped by the rubber elastic body 4. In particular, since the dynamic spring constant of the rubber elastic body 4 can be changed in accordance with the resonance frequency determined by the orifice passage 14, the vibration damping effect achieved by the desired dynamic spring constant can be exhibited under different use conditions by setting the resonance frequency as a boundary of different frequency characteristics required depending on the use conditions such as the running section of the railway vehicle.

When the required frequency differs depending on the difference in the travel section or the like, the flow path member 12 may be replaced with one having different vibration characteristics by changing the cross-sectional area, pitch, lead, and the like of the orifice passage 14 in accordance with the frequency. In this case, the core member 6, the inner cylinder 5, the outer cylinder member 3, and the rubber elastic body 4 other than the flow path member 12 can be used in common without change.

In this way, with the rubber bush 1 of embodiment 1 described above, by providing the independent flow path member 12 having the orifice passage 14 that communicates the

liquid chambers

9, 9 with each other on the shaft center member 2, it is possible to change the vibration characteristics by replacing the flow path member 12 having a different type of the orifice passage 14. Therefore, it is possible to cope with a plurality of vibration characteristics by changing the flow path member 12 at the minimum necessary, and it is possible to expect sharing of components and improvement of the degree of freedom in design.

In particular, since the flow path member 12 is formed as a shaft body that is fitted into the through hole 11 formed in the shaft member 2 and that communicates the

liquid chambers

9, 9 with each other and is provided with the orifice passage 14 recessed in the outer periphery, the flow path member 12 can be easily replaced.

Further, since the orifice passage 14 is formed in a spiral shape around the axis of the shaft body, the vibration characteristics can be easily set by changing the cross-sectional area, pitch, and the like.

In embodiment 1, the flow path member 12 is inserted and housed in the entire length of the through hole 11, but a flow path member shorter than the through hole 11 may be inserted and housed. In addition, the cross-sectional area, pitch, and the like of the throttle passage 14 may be locally changed in the flow passage member 12.

Next, another embodiment of the present invention will be described. The same components as those in embodiment 1 are denoted by the same reference numerals, and redundant description thereof is omitted.

[ embodiment 2]

In the rubber bush 1A shown in fig. 2 a and 2B, the core member 6 of the axial member 2 is divided into two upper and lower divided

members

6A and 6B with a plane orthogonal to the axial center of the core member 6 and including the

liquid chambers

9 and 9 as a boundary, and zigzag half-divided flow paths 15A and 15B each having a straight line portion in the front-rear direction and folded back at a position close to the liquid chamber 9 are formed on the contact surfaces (divided surfaces) of the two divided

members

6A and 6B. Therefore, in a state where the

split members

6A and 6B are fitted in the inner cylinder 5, the half-split flow paths 15A and 15B are butted against each other to form the meandering throttle passage 15 connecting the communication holes 10 and 10.

Reference numerals

16 and 16 denote O-rings for sealing.

Therefore, in the rubber bush 1A, since the dynamic spring constant can be changed according to the resonance frequency determined by the orifice passage 15, the vibration damping effect by the desired dynamic spring constant can be exhibited under different use conditions by setting the resonance frequency which is a boundary of different frequency characteristics required according to the use conditions such as the running section of the railway vehicle.

When the required frequencies are different depending on the difference in the traveling section or the like, the divided

members

6A and 6B in which the half-divided flow paths 15A and 15B having different vibration characteristics are formed may be replaced by those in which the cross-sectional area of the orifice passage 15, the width of the meandering passage, or the like is changed in accordance with the frequencies. In this case, the inner tube 5, the outer tube member 3, and the rubber elastic body 4 other than the core member 6 can be used as they are.

As described above, in the rubber bush 1A according to embodiment 2, the vibration characteristics can be changed by replacing the core member 6 having the different type of the orifice passage 15 by providing the core member 6 (divided

members

6A and 6B) having the orifice passage 15 for communicating the

liquid chambers

9 and 9 with each other on the shaft center member 2. Therefore, it is possible to cope with a plurality of vibration characteristics by changing the core member 6 at the minimum necessary, and it is possible to expect sharing of components and improvement of the degree of freedom in design.

In particular, here, the core member 6 is provided as a pair of divided

members

6A and 6B divided into two parts in the axial direction of the core member 6 with a plane orthogonal to the axial center of the core member 6 and including the

liquid chambers

9 and 9 as a boundary, and the orifice passage 15 is formed between the mutually divided surfaces of the two divided

members

6A and 6B, whereby the structure is reasonable in which the orifice passage 15 is formed at the same time as the divided

members

6A and 6B are assembled.

In embodiment 2, the half-divided flow paths are formed on the respective divided surfaces of the divided members to form the throttle passages, but the throttle passages may be formed in a zigzag shape only on one of the divided surfaces and may be closed by the flat contact surface of the other divided surface. In this case, it is sufficient to replace only the partition member in which the orifice passage is formed.

The meandering shape of the throttle passage may be a straight line portion in the left-right direction, and the meandering shape is not limited to the meandering shape, and may be another form.

[ embodiment 3]

In the rubber bush 1B shown in fig. 3(a) and 3(B), the inner tube 5 of the axial member 2 is divided into two parts, an inner part 5A and an outer part 5B, in the radial direction, and the communication holes 10, 10 are formed only in the outer part 5B, and in the inner part 5A, the

small holes

17A, 17B communicating with the respective communication holes 10 are formed so as to be displaced from each other in the vertical direction so that one is located above the communication holes 10 and the other is located below the communication holes 10.

A spiral groove 18 is formed in the outer peripheral surface of the core member 6 as a flow path member in a state where one end thereof communicates with the upper small hole 17A and the other end thereof communicates with the lower small hole 17B, and a spiral throttle passage 19 connecting the communication holes 10, 10 is formed between the inner peripheral surface of the inner portion 5A and the outer peripheral surface of the core member 6.

Therefore, in the rubber bush 1B, since the dynamic spring constant can be changed in accordance with the resonance frequency determined by the orifice passage 19, the vibration damping effect by the desired dynamic spring constant can be exhibited under different usage conditions by setting the resonance frequency which is a boundary of different frequency characteristics required depending on the usage conditions such as the travel section of the railway vehicle.

When the required frequency differs depending on the difference in the traveling section or the like, the core member 6 may be replaced with one having different vibration characteristics by changing the cross-sectional area, pitch, or the like of the orifice passage 19 in accordance with the frequency. In this case, the inner tube 5, the outer tube member 3, and the rubber elastic body 4 other than the core member 6 can be used as they are. However, the inner portion 5A having different sizes and axial intervals of the

small holes

17A and 17B may be replaced as necessary.

In this way, in the rubber bush 1B according to embodiment 3, too, the vibration characteristics can be changed by replacing the core member 6 having a different model of the orifice passage 19 by providing the core member 6 having the orifice passage 19 for communicating the

liquid chambers

9, 9 with each other on the shaft center member 2. Therefore, it is possible to cope with a plurality of vibration characteristics by changing the core member 6 at the minimum necessary, and it is possible to expect sharing of components and improvement of the degree of freedom in design.

In particular, since the flow passage member is provided as the core member 6 which is fitted into the inner cylinder 5 and has the orifice passage 19 formed on the outer peripheral surface, the core member 6 is assembled and the orifice passage 19 is formed reasonably. Further, since the orifice passage 19 is formed in a spiral shape centering on the axis of the core member 6, the vibration characteristics can be easily set.

In embodiment 3, the cross-sectional area, pitch, and the like of the orifice passage 19 may be locally changed on the outer periphery of the core member 6. The spiral orifice passage is not limited to the one, and other patterns such as a meandering shape may be adopted.

[ embodiment 4]

In the rubber bush 1C shown in fig. 4(a) and 4(B), the inner tube 5 of the shaft member 2 is divided into two parts, an inner part 5A and an outer part 5B, in the radial direction as in embodiment 3, and communication holes 10, 10 are formed only in the outer part 5B, and

small holes

20, 20 communicating with the centers of the communication holes 10 are formed in the inner part 5A.

A through hole 11 coaxially communicating with the

small holes

20, 20 is formed in the core member 6 with a diameter larger than the small hole 20 in the front-rear direction, a spiral tube 21 as a flow path member is inserted into the through hole 11, and both ends are connected to the

small holes

20, 20.

Therefore, in the rubber bush 1C as well, since the dynamic spring constant can be changed in accordance with the resonance frequency determined by the spiral flow path of the pipe 21, the vibration damping effect by the desired dynamic spring constant can be exhibited under different usage conditions by setting the resonance frequency which is a boundary of different frequency characteristics required depending on the usage conditions such as the travel section of the railway vehicle.

When the required frequency differs depending on the difference in the traveling zone or the like, the tube 21 may be replaced with a tube 21 having different vibration characteristics by changing the cross-sectional area, the number of turns, or the like in accordance with the frequency. In this case, the core member 6, the outer cylindrical member 3, and the rubber elastic body 4 other than the tube 21 can be used in common without change. The inner part 5A having different sizes of the

small holes

20, 20 may be replaced as necessary.

In this way, in the rubber bush 1C according to embodiment 4, the vibration characteristics can be changed by replacing the tube 21 having a different flow path design by providing the separate tube 21 having the flow path for communicating the

liquid chambers

9, 9 with each other on the shaft center member 2. Therefore, it is possible to cope with a plurality of vibration characteristics by changing the pipe 21 to the minimum necessary, and it is possible to expect sharing of components and improvement of the degree of freedom in design.

In particular, the flow path member is herein a tube 21 inserted into the through hole 11 formed in the shaft member 2 between the

liquid chambers

9, 9 and having both ends connected to the liquid chambers 9, respectively, so that it can be easily replaced. Further, by forming the pipe 21 in a spiral shape, the vibration characteristics can be easily set.

The tube is not limited to a spiral shape having an equal outer diameter, and may have a partially different diameter. In addition to the spiral shape, other patterns such as a meandering shape may be used.

[ embodiment 5]

In the rubber bush 1D shown in fig. 5(a) and 5(B), the core member 6 of the axial center member 2 is axially divided into two upper and lower divided

members

6A and 6B as in embodiment 2, but the lower divided member 6B is formed integrally with the inner tube 5, and the inner tube 5 is a bottomed tube shape closing the lower portion.

In addition, a zigzag groove 22 is formed in the lower surface of the upper partition member 6A. Therefore, in a state where the partition member 6A as the flow path member is fitted in the inner cylinder 5, the lower surface of the concave groove 22 is closed by the upper surface of the partition member 6B, thereby forming the meandering throttle passage 23 connecting the communication holes 10, 10. The O-ring 16 is provided only on the partition member 6A side.

Therefore, in the rubber bush 1D, since the dynamic spring constant can be changed according to the resonance frequency determined by the orifice passage 23, the vibration damping effect by the desired dynamic spring constant can be exhibited under different use conditions by setting the resonance frequency that is the boundary of different frequency characteristics required according to the use conditions such as the travel section of the railway vehicle.

When the required frequency differs depending on the difference in the traveling section or the like, the sectional area of the orifice passage 23, the width of the meandering passage, or the like may be changed in accordance with the frequency, so that the divided members 6A having different vibration characteristics are used instead. In this case, the inner tube 5, the outer tube member 3, and the rubber elastic body 4 including the split member 6B can be used as they are.

As described above, in the rubber bush 1D according to embodiment 5, the axial core member 2 is provided with the independent flow path member (the split member 6A) having the orifice passage 23 for communicating the

liquid chambers

9, 9 with each other, and the vibration characteristics can be changed by replacing the split member 6A having the different type of the orifice passage 23. Therefore, it is possible to cope with a plurality of vibration characteristics by changing the partition member 6A to the minimum necessary, and it is possible to expect sharing of components and improvement of the degree of freedom in design.

Here, similarly, the meandering shape of the throttle passage may be a straight line portion in the left-right direction, and the meandering shape is not limited to the meandering shape, and may be another form. In contrast to the above embodiment, the upper divided member may be formed integrally with the inner tube, and the lower divided member may be an independent flow path member having an orifice passage formed in the upper surface. Further, the divided members need not be formed with the same thickness in the upper and lower directions, and for example, the thickness of the lower divided member may be reduced to form the orifice passage in the lower surface and the peripheral surface of the upper divided member as the flow passage member.

The embodiments are common, and the number of liquid chambers is not limited to two, and may be 3 or more. In this case, the structure of the flow path member is appropriately changed in design so that the flow path of the flow path member communicates with each liquid chamber. In embodiment 1, it is conceivable that the through hole is branched into each liquid chamber, and a flow path member accommodating the shaft body is inserted into each branch hole. In embodiment 4, the tube may be branched into three or more in accordance with the number of liquid chambers.

The embodiment of the rubber bush other than the flow path member may be appropriately modified, and for example, a positioning portion (for example, a locking portion such as a protrusion is provided on the inner circumferential surface of the inner tube, and a locked portion such as a groove is provided on the outer circumferential surface of the core member) for matching the phases of the liquid chamber and the orifice passage may be provided.

Claims

1. A rubber bushing for a railway vehicle, comprising: a shaft member (2); an outer tube member (3) disposed coaxially with the shaft center member (2) and outside the shaft center member (2); and a rubber elastic body (4) elastically connecting the shaft center member (2) and the outer cylinder member (3), the rubber elastic body having liquid chambers (9, 9) in which a fluid is sealed at least at point-symmetrical positions around the shaft center member, the rubber bush (1) for a railway vehicle being characterized in that,

the shaft member (2) includes an independent flow path member (12) having a flow path for allowing the liquid chambers (9, 9) to communicate with each other, and the flow path member (12) is a shaft body that is fitted into a through hole formed in the shaft member (2) and allowing the liquid chambers (9, 9) to communicate with each other, and the flow path is recessed in the outer periphery of the shaft body.

2. A rubber bushing for a railway vehicle, comprising: a shaft member (2); an outer tube member (3) disposed coaxially with the shaft center member (2) and outside the shaft center member (2); and a rubber elastic body (4) elastically connecting the shaft center member (2) and the outer cylinder member (3), the rubber elastic body having liquid chambers (9, 9) in which a fluid is sealed at least at point-symmetrical positions around the shaft center member, the rubber bush (1) for a railway vehicle being characterized in that,

the axial core member (2) comprises an independent flow path member (12) having a flow path for communicating the liquid chambers (9, 9) with each other, the flow path member (12) is a divided member obtained by dividing the axial core member at a boundary with a plane which is orthogonal to the axial core of the axial core member (2) and contains the liquid chambers (9, 9), and the flow path is formed on a dividing surface of the divided member.

3. A rubber bushing for a railway vehicle, comprising: a shaft member (2); an outer tube member (3) disposed coaxially with the shaft center member (2) and outside the shaft center member (2); and a rubber elastic body (4) elastically connecting the shaft center member (2) and the outer cylinder member (3), the rubber elastic body having liquid chambers (9, 9) in which a fluid is sealed at least at point-symmetrical positions around the shaft center member, the rubber bush (1) for a railway vehicle being characterized in that,

the shaft center member (2) includes an independent flow path member (12) having a flow path for communicating the liquid chambers (9, 9) with each other, the shaft center member (2) has an inner cylinder for connecting the rubber elastic bodies at the outer periphery thereof, and the flow path member (12) is a core member fitted in the inner cylinder and having the flow path formed at the outer peripheral surface thereof.

4. A rubber bushing for a railway vehicle, comprising: a shaft member (2); an outer tube member (3) disposed coaxially with the shaft center member (2) and outside the shaft center member (2); and a rubber elastic body (4) elastically connecting the shaft center member (2) and the outer cylinder member (3), the rubber elastic body having liquid chambers (9, 9) in which a fluid is sealed at least at point-symmetrical positions around the shaft center member, the rubber bush (1) for a railway vehicle being characterized in that,

the shaft member (2) includes an independent flow path member (12) having a flow path for communicating the liquid chambers (9, 9) with each other, the flow path member (12) is a tube inserted into a through hole formed in the shaft member (2) between the liquid chambers (9, 9), and ends of the tube are connected to the liquid chambers, respectively.