Rail Car

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to Japanese Patent Application No. 2023-201769, filed Nov. 29, 2023. The contents of this application are incorporated herein by reference in their entirety.

TECHNICAL FIELD

The present invention relates to a rail car.

DESCRIPTION OF THE RELATED ART

Rail cars that travel on rails laid on the ground are each made up of a hexahedral rail car shell and bogies that support the rail car shell and that are movable along the rails.

The rail car shell includes an underframe providing a floor, a pair of end structures erected at both longitudinal ends of the underframe, a pair of side structures erected at both transverse ends of the underframe, and a roof structure mounted on upper ends of the end structures and the side structures.

The underframe is made up of a floor assembly, side beams and end beams disposed on peripheral edges of the floor assembly, bolster beams disposed in portions of the floor assembly that support the bogies, and the like. Traction forces and braking forces are transmitted from the bogies through the bolster beams, i.e., the underframe, to the rail car shell.

A yaw damper support is disposed on transverse ends of each of the bolster beams, and a yaw damper for damping yawing motion of the bogie that occurs in a horizontal plane at the time the rail car travels at high speeds is connected to a lower end of the yaw damper support. The yaw damper support has an upper end connected to a yaw damper holder disposed on the underframe, i.e., on the rail car shell.

JP-2014-125138-A discloses an underframe structure for railway cars that is capable of reducing out-of-plane bending stresses produced on an upper flange and a lower flange at the time a couple of forces act on the lower flange at a position where a bolster anchor or a yaw damper support bracket is fastened.

SUMMARY OF INVENTION

As the speed of a railway car increases, the bogie that is subject to rail irregularities tends to give rise to yawing, i.e., swinging in a horizontal plane. Therefore, loads acting on the yaw damper support that is connected to the yaw damper for damping the yawing of the bogie and the yaw damper holder that serves as a joint between the yaw damper support and the underframe also tend to become larger.

Moreover, since the yaw damper support that is connected to the yaw damper is connected to the yaw damper holder, the yaw damper holder is required to be installed on the underframe with high positional accuracy to prevent the yaw damper that interconnects the car shell and the bogie from going beyond railway car limitations when the car shell is tilted or travels along curved rails.

When the yaw damper holder is welded to a transverse end of the underframe, it is desirable to reduce the amount of heat applied to weld the yaw damper holder, by shortening weld lines so that thermal deformation of welded parts and the number of manhours required to perform a nondestructive inspection on the welded parts will not grow large.

It is an object of the present invention to provide a rail car that is capable of efficiently transmitting vibrational forces that have been transmitted from a bogie via a yaw damper and a yaw damper support to an underframe to a rail car shell, and that is of a simple structure, sufficient mechanical strength, and light weight for reducing the amount of heat applied to perform welding and for allowing a nondestructive inspection to be performed with ease.

In order to achieve the above object, there is provided, as a representative one of rail cars according to the present invention, a rail car including a rail car shell, a bogie that supports the rail car shell, a yaw damper having an end connected to the bogie, and a yaw damper support to which another end of the yaw damper is connected. The rail car shell includes an underframe including a floor assembly providing a floor and a bolster beam joined to the floor assembly, and a pair of side structures erected at both transverse ends of the underframe. In this rail car, the yaw damper support is fixed to a transverse end of the bolster beam.

According to the present invention, it is possible to provide a rail car that is capable of efficiently transmitting vibrational forces that have been transmitted from a bogie via a yaw damper and a yaw damper support to an underframe to a rail car shell, and that is of a simple structure, sufficient mechanical strength, and light weight for reducing the amount of heat applied to perform welding and for allowing a nondestructive inspection to be performed with ease.

Objects, configurations, and advantages other than those described above will be clarified by the following description of a preferred embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of a railway car;

FIG. 2 is a cross-sectional view of a lower portion of a side structure and a transverse end of an underframe having a bolster beam of the railway car according to the present invention;

FIG. 3 is a perspective view of the bolster beam according to the present invention;

FIG. 4 is a side elevational view of a bogie portion of the railway car that includes the bolster beam according to the present invention;

FIG. 5 is a cross-sectional view of a lower portion of a side structure and a transverse end of an underframe having a bolster beam of a railway car according to a comparative example; and

FIG. 6 is a side elevational view of a bogie portion of the railway car that includes the bolster beam according to the comparative example.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A rail car according to a preferred embodiment of the present invention will be described below with reference to the drawings. First, in order to explain configurations of the rail car, directions that are illustrated in the drawings will be defined as follows. A longitudinal direction of the rail car is defined as an x-direction, a transverse direction thereof as a y-direction, and a heightwise direction thereof as a z-direction. The respective directions may hereinafter be referred to simply as the x-direction, the y-direction, and the z-direction.

The rail car refers to a vehicle that travels on rails laid on the ground, and covers a railway car, a monorail car, a new transport system car, and a tramcar, for example. A railway car as a representative example of the rail car will be described below.

FIG. 1 illustrates a railway car in side elevation. The railway car, denoted by 1, has a hexagonal railway car shell and a pair of bogies 7 supporting lower surfaces of both ends in the x-direction of the railway car shell. The railway car shell includes an underframe 10A providing a floor, a pair of side structures 20 erected at both ends in the y-direction of the underframe 10A, a pair of end structures 30, which may include a front end structure, erected at both ends in the x-direction of the underframe 10A, and a roof structure 40 mounted on upper ends of the side structures 20 and the end structures 30. The bogies 7 that support the railway car shell move along rails 5.

The underframe 10A includes a floor assembly 10, side beams and end beams disposed on peripheral edges of the floor assembly 10, a pair of bolster beams 13 (see FIG. 2) disposed in portions of the floor assembly 10 that support the bogies 7. The bogies 7 that support the railway car shell are disposed beneath the respective bolster beams 13. Traction forces and braking forces are transmitted from the bogies 7 through the bolster beams 13 to the railway car shell.

Each of the side structures 20 has a plurality of openings defined therein, some as windows 22 and some as gateways 24 through which passengers and the like walk for embarking and disembarking. The underframe 10A supports in its lower portion various electric power devices including a main converter and an air compressor, for example. At least one of the end structures 30 has a through opening defined therein for passengers and the like to walk therethrough into and out of a next railway car. The roof structure 40 supports on its upper surface an air conditioner and a current collector, for example.

FIG. 2 illustrates in cross section a lower portion of one of the side structures 20 and a transverse end of the underframe 10A having the bolster beam 13 of the railway car according to the present invention.

The underframe 10A has the floor assembly 10 and the bolster beam 13 that is joined to the floor assembly 10. The floor assembly 10 is made up of an outer side plate 10a, an inner side plate 10b, and a plurality of joint plates 10c joining the outer side plate 10a and the inner side plate 10b to each other. The floor assembly 10 is constructed as a hollow extrusion-molded structure that has been extruded in the x-direction.

Similarly, the side structure 20 is made up of an outer side plate 20a, an inner side plate 20b, and a plurality of joint plates 20c joining the outer side plate 20a and the inner side plate 20b to each other. The side structure 20 is constructed as a hollow extrusion-molded structure that has been extruded in the x-direction.

The side structures 20 are erected at both ends in the y-direction of the underframe 10A, i.e., of the floor assembly 10. The outer side plate 10a of the floor assembly 10 and the outer side plate 20a of the side structure 20 are joined to each other, and the inner side plate 10b of the floor assembly 10 and the inner side plate 20b of the side structure 20 are joined to each other, for example, as by welding.

The underframe 10A has the bolster beam 13 on a lower surface of the floor assembly 10 that lies above the bogie 7. The bolster beam 13 includes a plate-like horizontal assembly 13A and a pair of protrusive assemblies 13B (one illustrated in FIG. 2) extending along the x-direction and protruding in the z-direction from both ends in the y-direction of the horizontal assembly 13A.

The horizontal assembly 13A is made up of a lower plate 13Aa, an upper plate 13Ab, and a plurality of joint plates 13Ac joining the lower plate 13Aa and the upper plate 13Ab to each other. Each of the protrusive assemblies 13B is made up of an inner side plate 13Bb near the end in the y-direction of the underframe 10A, i.e., near a lower end of the side structure 20, an outer side plate 13Ba spaced from the inner side plate 13Bb, and a joint plate 13Bc joining the inner side plate 13Bb and the outer side plate 13Ba to each other. The outer side plate 13Ba and the inner side plate 13Bb extend upwardly in the z-direction in comparison with the lower surface of the floor assembly 10. The joint plate 13Bc is inclined to extend from an upper end of the outer side plate 13Ba in a direction extending upwardly in the z-direction and toward the center of the railway car in the y-direction.

The outer side plate 13Ba and the joint plate 13Bc may not be separate from each other and may be integrally molded together. For example, the outer side plate 13Ba may have an upward extension, not depicted, extending further upwardly in the z direction from the upper end, indicated by C in FIG. 2, of the outer side plate 13Ba extending along the z-direction. Similarly, the inner side plate 13Bb may have an upward extension, not depicted, extending further along the outer side plate 20a of the side structure 20. The upward extension of the outer side plate 13Ba and the upward extension of the inner side plate 13Bb may have respective upper ends joined together.

The upper plate 13Ab of the horizontal assembly 13A of the bolster beam 13 and the inner side plate 13Bb of the protrusive assembly 13B are held against the outer side plate 10a of the floor assembly 10. A cross-sectional shape across the x-direction of a lower surface of the outer side plate 10a of the floor assembly 10 and a cross-sectional shape across the x-direction of upper surfaces of the upper plate 13Ab and the inner side plate 13Bb of the bolster beam 13 are essentially identical to each other. Consequently, when the bolster beam 13 is fitted upwardly over the floor assembly 10, i.e., when the upper surfaces of the upper plate 13Ab and the inner side plate 13Bb are brought into abutting engagement with the lower surface of the outer side plate 10a, the bolster beam 13 and the floor assembly 10 are snugly combined together against relative displacement in the y-direction. After the bolster beam 13 and the floor assembly 10 have thus been put together, the upper end of the inner side plate 13Bb of the bolster beam 13 and a lower end of the outer side plate 20a of the side structure 20 or an upper end of the outer side plate 10a of the floor assembly 10 are welded to each other by a welded joint D.

A dimension W2 in the y-direction of the bolster beam 13 is set larger than a dimension W1 in the y-direction of the lower surface, i.e., the horizontal surface, of the floor assembly 10. An end in the y-direction of the bolster beam 13 thus protrudes horizontally beyond the end in the y-direction of the floor assembly 10 outwardly away from the center in the y-direction of the railway car shell. The bolster beam 13 and the floor assembly 10 as they are in the dimensional and structural relation described above are joined together, making up the underframe 10A. A yaw damper support 17 that is mechanically fastened to an end of a yaw damper 8 (see FIG. 4) is connected at an appropriate position to a lower surface of the lower plate 13Aa at the end in the y-direction of the horizontal assembly 13A of the bolster beam 13, i.e., at the protruding end in the y-direction of the bolster beam 13. The other end of the yaw damper 8 is connected to a side surface of the bogie 7.

FIG. 3 illustrates in perspective the bolster beam 13 according to the present embodiment. FIG. 4 illustrates in side elevation the bogie portion of the railway car that includes the bolster beam 13 according to the present embodiment. The bolster beam 13 is of a plane-symmetrical shape with respect to a plane B extending parallel to an xz-plane across the center in the y-direction of the bolster beam 13. Therefore, only one-half in the y-direction of the bolster beam 13 is illustrated in FIG. 3.

The protrusive assembly 13B of the bolster beam 13 is disposed on an upper surface of the end in the y-direction of the horizontal assembly 13A of the bolster beam 13 and extends fully along a length L in the x-direction of the bolster beam 13. The protrusive assembly 13B is of a hollow extrusion-molded structure that has been extruded in the x-direction. Similarly, the horizontal assembly 13A is also of a hollow extrusion-molded structure that has been extruded in the x-direction. The horizontal assembly 13A and the protrusive assembly 13B are extrusion-molded integrally together. The end in the y-direction of the horizontal assembly 13A and the protrusive assembly 13B also function as a yaw damper holder 14 to which the yaw damper support 17 is fixedly mounted. The bolster beam 13 is made up of a plurality of hollow extrusion-molded structures that have been extruded in the x-direction and joined together.

The bolster beam 13 has a central pin 18 extending vertically downwardly in a-z-direction from a lower surface of a central portion of the horizontal assembly 13A, i.e., a central portion in the x-direction and the y-direction of the bolster beam 13. The bogie 7 supports the railway car shell with an air spring 9 interposed therebetween through the central pin 18 of the bolster beam 13, i.e., of the underframe 10A, that extends centrally through a horizontal surface of a bogie frame, not depicted, of the bogie 7.

When the railway car 1 travels along curved rails or through a turnout, the bogies 7 swing about the respective central pins 18 to follow the curvature of the rails 5. Traction forces and braking forces are transmitted from the bogies 7 through the central pins 18 and the bolster beams 13, i.e., the underframe 10A, to the railway car shell.

FIG. 5 illustrates in cross section a lower portion of a side structure and a transverse end of an underframe having a bolster beam of a railway car according to a comparative example. FIG. 6 illustrates in side elevation a bogie portion of the railway car that includes the bolster beam according to the comparative example.

Features of the railway car and its bolster beams according to the comparative example will be described below. Structural details of some components of the railway car according to the comparative example that are similar to those of the components described above according to the embodiment of the present invention will be omitted from detailed description. The dimension, corresponding to the dimension W2 in FIG. 2, in the y-direction of the bolster beam 13 according to the comparative example and the dimension, corresponding to the dimension W1 in FIG. 2, in the y-direction of the lower surface of the floor assembly 10 constituting the underframe 10A are essentially the same as each other. A yaw damper holder 14 extends between and is welded to the end in the y-direction of the floor assembly 10 constituting the underframe 10A and the lower end of the side structure 20. The yaw damper support 17 is mechanically fastened to a lower surface of the yaw damper holder 14 that is welded to the side structure 20 and the underframe 10A.

The yaw damper holder 14 is an independent component that does not belong to the side structure 20 and the floor assembly 10 constituting the underframe 10A. Assembling of the railway car shell is performed by holding the lower ends of the side structures 20 in abutment against the ends in the y-direction of the underframe 10A and welding them together. Therefore, relatively large assembling tolerances are allowed for the dimensions of the components of the assembled railway car shell.

As in the comparative example, with such relatively large assembling tolerances, when the yaw damper holder 14 as it extends between the end in the y-direction of the underframe 10A, i.e., of the floor assembly 10, and the lower end of the side structure 20 is welded to the underframe 10A and the side structure 20, the yaw damper holder 14 is required to be positioned with high accuracy. In addition, it is necessary to adjust the gap to be welded between an upper end of the yaw damper holder 14 and the side structure 20 and also to adjust the gap to be welded between a lower end of the yaw damper holder 14 and the underframe 10A.

Therefore, a large number of manhours are required to position the yaw damper holder 14 when it is to be installed on the railway car shell, to adjust the gaps to be welded between the yaw damper holder 14 and the railway car shell, and to perform a nondestructive inspection on the welded joints.

Advantages of Present Embodiment

The rail car according to the embodiment of the present invention offers various advantages over the related art as follows. Since the yaw damper holder 14 is integrally included in each end in the y-direction of the bolster beam 13, it is not necessary to prepare separate yaw damper holders 14. Therefore, the rail car has a reduced number of parts and is a relatively simple structure.

Further, the end in the y-direction of the bolster beam 13 has a base material structure having high allowable stresses, the structure doubling as the yaw damper holder 14 that is subject to relatively large loads. Consequently, the yaw damper support 17 can mechanically be fastened to the base material structure as the yaw damper holder 14. The rail car can thus be provided with the yaw damper holder 14 having a high safety factor in terms of mechanical strength.

Moreover, inasmuch as the bolster beam 13 includes the protrusive assembly 13B extending along the x-direction and protruding in the z-direction from each end in the y-direction of the horizontal assembly 13A, the bolster beam 13 is highly rigid against moment-inducing loads that are applied about a y-axis along the y-direction and caused by traction forces and braking forces along the x-direction of the bogie 7. Hence, as the horizontal assembly 13A to which the central pin 18 is fixed does not need to be significantly reinforced, the rail car can be provided with the bolster beam 13 that is lightweight and highly rigid.

According to the present embodiment, there is provided a rail car that is capable of efficiently transmitting vibrational forces that have been transmitted from a bogie via a yaw damper and a yaw damper support to an underframe to a rail car shell, and that is of a simple structure, sufficient mechanical strength, and light weight for reducing the amount of heat applied to perform welding and for allowing a nondestructive inspection to be performed with ease.

It is to be noted that the present invention is not limited to the embodiment described above and that the embodiment may be modified in various manners. For example, the above embodiment has been described in detail for an easier understanding of the present invention, and the present invention should not be limited to anything that includes all of the details described above. Further, some of the details of the embodiment may be replaced with details of another embodiment or other embodiments, and details of the embodiment may be added to other details of another embodiment or other embodiments. Moreover, some of the details of each of the embodiments may be deleted, or may be added to or replaced with details of another embodiment or other embodiments.

The present specification includes the disclosure of the following inventions.

First Aspect

A rail car includes a rail car shell, a bogie that supports the rail car shell, a yaw damper having an end connected to the bogie, and a yaw damper support to which another end of the yaw damper is connected. The rail car shell includes an underframe including a floor assembly providing a floor and a bolster beam joined to the floor assembly, and a pair of side structures erected at both transverse ends of the underframe. In the rail car, the yaw damper support is fixed to a transverse end of the bolster beam.

Second Aspect

In the rail car according to the first aspect, the bolster beam is larger in transverse dimension than the floor assembly.

Third Aspect

In the rail car according to the first or second aspect, the bolster beam includes a horizontal assembly that is held against a lower surface of the floor assembly, and a protrusive assembly that protrudes upwardly from a transverse end of the horizontal assembly.

Fourth Aspect

In the rail car according to the third aspect, the transverse end of the horizontal assembly and the protrusive assembly are integrally extrusion-molded along a longitudinal direction of the rail car as a hollow extrusion-molded structure.

Fifth Aspect

In the rail car according to the third or fourth aspect, the protrusive assembly is joined to a lower end of each of the side structures.

Sixth Aspect

In the rail car according to the fifth aspect, the yaw damper support is connected to a lower surface of the transverse end of the horizontal assembly.

Seventh Aspect

In the rail car according to any one of the third to sixth aspects, the protrusive assembly includes an inner side plate near a transverse end of the underframe, an outer side plate spaced from the inner side plate, and a joint plate joining the inner side plate and the outer side plate to each other.

Eighth Aspect

In the rail car according to any one of the third to seventh aspects, a cross-sectional shape across a longitudinal direction of the lower surface of the floor assembly and a cross-sectional shape across the longitudinal direction of upper surfaces of the horizontal assembly and the protrusive assembly of the bolster beam are essentially identical to each other, and the bolster beam and the floor assembly are assembled together such that the upper surfaces of the horizontal assembly and the protrusive assembly of the bolster beam are held in engagement with the lower surface of the floor assembly.

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Priority Claims (1)