Railcar bogie and railcar including same

A railcar bogie includes: a cross beam extending in a car width direction and supporting a carbody; plate springs extending in a car longitudinal direction and supporting both respective car-width-direction end portions of the cross beam; axle boxes accommodating respective bearings for axles and supporting respective car longitudinal-direction end portions of the plate springs; plate spring receivers each located between the plate spring and the axle box and including an upper surface which is inclined toward a longitudinal-direction middle portion of the plate spring, the upper surface receiving the plate spring; and stoppers arranged so as to cover at least a part of an upper surface of the plate spring, the part being located above the axle box.

TECHNICAL FIELD

The present invention relates to a bogie supporting a carbody of a railcar, and particularly to a railcar bogie which prevents a plate spring from falling.

BACKGROUND ART

Typically, a bogie of a railcar is constituted by wheels, axles, and a bogie frame. The bogie frame includes a cross beam and a pair of side sills. The cross beam extends in a railcar width direction. The side sills are joined to both respective ends of the cross beam by welding or the like and extend in a front/rear direction. Axle boxes accommodating respective bearings for supporting the axle are supported by an axle box suspension and are configured to be displaceable in an upper/lower direction relative to the bogie frame. Problems of such a bogie are that the manufacturing cost is high due to a large number of welded portions, and the weight of the bogie is heavy. Here, PTL 1 proposes a bogie from which side sills are omitted.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

The bogie described in PTL 1 is configured such that: plate springs are used as primary suspensions; front/rear direction middle portions of the plate springs are fixed to both respective railcar width direction end portions of a cross beam; and both front/rear direction end portions of the plate springs are inserted in respective spring receiving portions provided at respective axle boxes. Each of the spring receiving portions described in PTL 1 has a tubular shape, and work of inserting the plate spring into the spring receiving portion is not easy. In addition, the bogie including the plate spring is required to have such a structure that the plate spring hardly falls.

The present invention was made under these circumstances, and an object of the present invention is to provide a railcar bogie including a plate spring, the railcar bogie being configured such that: the plate spring is easily attached to the railcar bogie; and the plate spring hardly falls.

Solution to Problem

A railcar bogie according to one aspect of the present invention includes: a cross beam extending in a car width direction and supporting a carbody; plate springs extending in a car longitudinal direction and supporting both respective car-width-direction end portions of the cross beam; axle boxes accommodating respective bearings for axles and supporting respective car longitudinal-direction end portions of the plate springs; plate spring receivers each located between the plate spring and the axle box and including an upper surface which is inclined toward a longitudinal-direction middle portion of the plate spring, the upper surface receiving the plate spring; and stoppers each arranged in a vicinity of the car longitudinal-direction end portion of the plate spring so as to cover at least a part of an upper surface of the plate spring, the car longitudinal-direction end portion being located above the axle box.

According to the above railcar bogie, the plate springs can be attached only by placing the members on the upper surfaces of the axle boxes in order, and the plate springs can be prevented from falling by the stoppers.

Advantageous Effects of Invention

According to the above configuration, the present invention can provide the railcar bogie configured such that: the plate spring is easily attached to the railcar bogie; and the plate spring hardly falls.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments will be explained in reference to the drawings. In the following explanations and drawings, the same reference signs are used for the same or corresponding components, and a repetition of the same explanation is avoided.

First Embodiment

First, a bogie100according to the first embodiment will be explained in reference toFIGS. 1 to 5.FIG. 1is a side view of the bogie100.FIG. 2is a plan view of the bogie100. A left/right direction on the sheet ofFIG. 1corresponds to a “car longitudinal direction”, and a direction perpendicular to the sheet ofFIG. 1corresponds to a “car width direction”. As shown inFIGS. 1 and 2, the bogie100is used for a railcar102and includes wheels10, axle boxes20, a cross beam30, plate springs40, plate spring receivers50, gap bodies60, and stoppers70.

The wheels10are provided at four respective positions of the bogie100. As shown inFIG. 2, the wheels10opposed to each other in the car width direction are coupled to each other by an axle11. The axles11are held by bearings12at positions outside the wheels10in the car width direction. The bogie100according to the present embodiment is a so-called trailing bogie and does not include a driving device. However, in the case of an electric bogie, the axle11is connected to an electric motor via a gear box and is driven by this electric motor.

Each of the axle boxes20is a member accommodating the bearing12and supporting the plate spring40via the plate spring receiver50and the gap body60described later.FIG. 3is an enlarged side view of an upper portion of the axle box20.FIG. 4is a plan view of the portion shown inFIG. 3.FIG. 5is an exploded view of the portion shown inFIG. 3. The axle box20includes an axle box main body21and a spring seat22placed on the axle box main body21. As shown inFIG. 5, a supporting surface23that is an upper surface of the spring seat22is inclined toward a longitudinal-direction middle portion of the plate spring40, and a columnar insertion piece24is formed at a middle of the supporting surface23. An insertion hole25is formed on a lower surface of the spring seat22, and an insertion piece26is formed on an upper surface of the axle box main body21.

The axle box20includes a locking member27. The locking member27is located at a car-longitudinal-direction outer side of the axle box main body21and formed so as to extend toward the car-longitudinal-direction outer side. The locking member27is formed so as to penetrate a below-described locking hole59(seeFIG. 4) formed at a locked member52of the plate spring receiver50. A shape of the locking member27is not especially limited. As shown inFIG. 5, in the present embodiment, a lower surface of a portion of the locking member27is formed to be concave, the portion being close to the axle box main body21. Therefore, once the locked member52is locked with the locking member27, the locked member52hardly comes off. A position of the locking member27is not especially limited. The locking member27may be attached to a car-width-direction side surface of the axle box main body21. To be specific, the locked member52is only required to be locked with the locking member27when the locked member52tries to move upward.

The cross beam30is a member supporting a carbody101. As shown inFIGS. 1 and 2, the cross beam30includes a pair of square pipes31and connecting members32. The square pipes31extend in the car width direction and are made of metal. The connecting members32are located near both respective car width direction ends of the square pipes31and connect the square pipes31to each other. Upper surfaces of the connecting members32hold respective air spring bases33. Air springs34that are secondary suspensions are attached to the respective air spring bases33. To be specific, the cross beam30supports the carbody101via the air springs34and the air spring bases33.

Each of the plate springs40is a member having both the function of a conventional coil spring (primary suspension) and the function of a conventional side sill. The plate springs40extend in the car longitudinal direction. Middle portions of the plate springs40support both respective car-width-direction end portions of the cross beam30via respective contacting members35. Both longitudinal-direction end portions of the plate spring40are supported by the axle boxes20via the plate spring receivers50and the like. In a side view, the plate spring40has a bow shape that is convex downward. Therefore, force in a direction toward the longitudinal-direction middle portion of the plate spring40is being applied to each of both car-longitudinal-direction end portions of the plate spring40at all times. A material of the plate spring40is not especially limited. For example, a composite material constituted by a lower layer portion made of fiber-reinforced resin and an upper layer portion made of thin metal may be used as the material of the plate spring40. The longitudinal-direction middle portion of the plate spring40is thicker than each of both longitudinal-direction end portions of the plate spring40.

Each of the plate spring receivers50is a member located at a longitudinal-direction end portion of the plate spring40and receiving the plate spring40on an upper surface of the plate spring receiver50. As shown inFIG. 3, each of the plate spring receivers50includes a plate spring receiver main body51and the locked member52attached to the plate spring receiver main body51. As shown inFIG. 4, the plate spring receiver main body51has a substantially rectangular shape in a plan view, and protective walls53are formed at three respective sides of the plate spring receiver main body51, the three sides being a car-width-direction inner side, a car-width-direction outer side, and a car-longitudinal-direction outer side. Further, as shown inFIG. 5, a rubber sheet54is laid on a portion of the plate spring receiver main body51, the portion being surrounded by the protective walls53. The plate spring receiver50receives the plate spring40via the rubber sheet54. The upper surface of the plate spring receiver50which receives the plate spring40is inclined toward the longitudinal-direction middle portion of the plate spring40. A columnar insertion piece55is formed on a lower surface of the plate spring receiver main body51.

The locked member52is a portion locked with the locking member27of the axle box20. As shown inFIG. 4, the locked member52of the present embodiment is a plate-shaped member having a substantially T shape. An attaching portion56that is an upper portion of the locked member52is fixed to a car-longitudinal-direction outer side surface of the plate spring receiver main body51by screws57. An extending portion58of the locked member52which is located under the attaching portion56extends to the axle box20. The extending portion58is provided with the locking hole59, and the locking member27of the axle box20is inserted into the locking hole59. To be specific, the locking member27penetrates the locking hole59. The locked member52is not limited to the above-described substantially T shape. For example, the attaching portion56may extend to both car-width-direction side surfaces of the plate spring receiver main body51and be fixed to these side surfaces. Or, the plate spring receiver main body51and the locked member52may be formed integrally.

The gap body60is a member arranged between the plate spring receiver50and the axle box20. As shown inFIG. 5, the gap body60is mainly constituted by: two elastic plates61; and a rubber seat62arranged between these two elastic plates61. Each of the elastic plates61and the rubber seat62has an annular shape. The elastic plate61at an upper side is formed by stacking a first metal plate63, a rubber layer64, and a second metal plate65in this order from the upper side. The elastic plate61at a lower side is formed by stacking the second metal plate65, the rubber layer64, and the first metal plate63in this order from the upper side. Annular grooves66are formed on both respective surfaces of the rubber seat62, and the second metal plates65are fitted in the respective annular grooves66.

The stopper70is a member which prevents the plate spring40from falling. The stopper70is arranged in the vicinity of the longitudinal-direction end portion of the plate spring40so as to cover at least a part of the upper surface of the plate spring40, the longitudinal-direction end portion being located above the axle box20. The stopper70of the present embodiment includes an upper surface portion71and side surface portions72. The upper surface portion71is located above the plate spring40. The side surface portions72are located at both respective car-width-direction ends of the upper surface portion71and fixed to the side surfaces of the plate spring receiver50. Specifically, each of the side surface portions72is fixed to the car-width-direction side surface of the plate spring receiver50by screws73. In the present embodiment, the upper surface portion71is configured to cover the plate spring40entirely in the car width direction. However, the upper surface portion71may be configured to cover the plate spring40partially in the car width direction. For example, the stopper70may be formed in an L shape, and such stoppers70may be fixed to both respective car-width-direction side surfaces of the plate spring receiver50. The stopper70may not be configured to be detachable from the plate spring receiver50, but the stopper70and the plate spring receiver50may be formed integrally.

Next, a method of attaching the plate spring40will be explained in reference toFIG. 5. First, the insertion piece26of the axle box main body21is inserted into the insertion hole25of the spring seat22. Thus, the spring seat22is attached to the upper surface of the axle box main body21. Next, the insertion piece24of the spring seat22is inserted into an inner peripheral portion of the first metal plate63of the elastic plate61located at the lower side. Then, the rubber seat62is stacked on the upper surface of the elastic plate61located at the lower side, and the other elastic plate61is stacked on the rubber seat62. With this, the gap body60can be attached to the upper surface of the spring seat22. Next, the insertion piece55of the plate spring receiver main body51is inserted into an inner peripheral portion of the first metal plate63of the elastic plate61located at the upper side. Thus, the plate spring receiver main body51is attached to the upper surface of the gap body60. Next, the plate spring40is placed on the upper surface of the plate spring receiver main body51. Next, the locked member52and the stopper70are fixed to the plate spring receiver main body51. Thus, the work of attaching the plate spring40is completed. As above, according to the present embodiment, the plate spring40can be attached only by stacking these members in order. Therefore, the work of attaching the plate spring40is extremely easy.

As described above, the plate spring40has a bow shape. Therefore, the plate spring40is stable in a state where the force toward the longitudinal-direction middle portion is being applied to each of both longitudinal-direction end portions. Therefore, both longitudinal-direction end portions of the plate spring40are hardly displaced in the direction toward the longitudinal-direction middle portion. On this account, since the upper surface of the plate spring receiver50is inclined toward the longitudinal-direction middle portion of the plate spring40along the shape of the plate spring40, the plate spring40is hardly displaced on the upper surface of the plate spring receiver50. Thus, according to the present embodiment, although the plate spring40is attached just by stacking the members, the plate spring40does not fall in a normal operation state.

However, if an impact much higher than an impact at the time of the normal operation is applied to the plate spring40when, for example, the railcar102derails, the plate spring40may float up. If the plate spring40floats up, the plate spring40is caught by the stopper70, and the plate spring receiver50tries to float up. However, the locked member52of the plate spring receiver50is locked with the locking member27of the axle box20. Thus, the plate spring receiver50is prevented from floating up. As a result, the upward movement of the plate spring40relative to the axle box20is restricted. Thus, the plate spring40can be prevented from falling from the plate spring receiver50, and the plate spring receiver50can be prevented from falling from the axle box20.

Second Embodiment

Next, a bogie200according to the second embodiment will be explained in reference toFIGS. 6 and 7.FIG. 6is an enlarged side view showing an upper portion of the axle box20of the bogie200according to the present embodiment.FIG. 7is a plan view of the portion shown inFIG. 6. As shown inFIGS. 6 and 7, the bogie100according to the first embodiment and the bogie200according to the present embodiment are different from each other in that: in the first embodiment, the stopper70is fixed to the plate spring receiver50; and in the present embodiment, two stoppers70are held by stopper holding members74. In the bogie200according to the present embodiment, the axle box20does not include the locking member27, and the plate spring receiver50does not include the locked member52.

The stopper holding members74are located at both respective car-width-direction sides of the plate spring40. Lower end portions of the stopper holding members74are fixed to the axle box20. As shown inFIG. 7, holding holes75are formed at two positions of an upper end portion of each stopper holding member74. Each of the stoppers70is a round rod made of metal and extends between the stopper holding members74in the car width direction. Internal screws are formed at end portions of the stopper70. The stoppers70are arranged so as to correspond to the holding holes75of the stopper holding members74. Each of screws76is screwed into the internal screw of the stopper70from the car width direction outer side of the stopper holding member74through the holding hole75. With this, the stopper70is fixed to the stopper holding member74. To be specific, the stoppers70are held by the stopper holding members74.

The bogie200according to the present embodiment is configured as above. Therefore, as with the first embodiment, the members are stacked, the plate spring40is then placed on the plate spring receiver main body51, and the stoppers70are finally attached to the stopper holding members74. Thus, the work of attaching the plate spring40is completed. As above, even in the present embodiment, the plate spring40can be attached easily. In the present embodiment, even if the plate spring40floats up, the plate spring40contacts the stopper70, so that the upward movement of the plate spring40is restricted. Therefore, in the bogie200according to the present embodiment, the upward movement of the plate spring40and the upward movement of the plate spring receiver50are restricted. Thus, the plate spring40can be prevented from falling from the plate spring receiver50, and the plate spring receiver50can be prevented from falling from the axle box20.

As above, each of the bogie according to the first embodiment and the bogie according to the second embodiment includes: a cross beam extending in a car width direction and supporting a carbody; plate springs extending in a car longitudinal direction and supporting both respective car-width-direction end portions of the cross beam; axle boxes accommodating respective bearings for axles and supporting respective car longitudinal-direction end portions of the plate springs; plate spring receivers each located between the plate spring and the axle box and including an upper surface which is inclined toward a longitudinal-direction middle portion of the plate spring, the upper surface receiving the plate spring; and stoppers each arranged in a vicinity of the car longitudinal-direction end portion of the plate spring so as to cover an upper surface of the plate spring, the car longitudinal-direction end portion being located above the axle box. Therefore, as described above, according to the bogie, the plate spring can be easily attached to the bogie, and the plate spring can be prevented from falling.

The bogie according to the first embodiment is configured such that: the stoppers are fixed to the respective plate spring receivers; and upward movements of the plate spring receivers relative to the axle boxes are restricted. Therefore, even if the plate spring receiver floats up by the plate spring contacting the stopper, the upward movement of the plate spring receiver is restricted. As a result, the upward movement of the plate spring itself is restricted. Thus, the plate spring can be prevented from falling.

The bogie according to the first embodiment is configured such that: the axle boxes include respective locking members; the plate spring receivers include respective locked members which are locked with the respective locking members; and the upward movements of the plate spring receivers relative to the axle boxes are restricted. Specifically, each of the locked members extends from a car-longitudinal-direction outer side of the plate spring receiver to the axle box and is provided with a locking hole, and each of the locking members extends toward the car-longitudinal-direction outer side and penetrates the locking hole. Therefore, the upward movement of the plate spring receiver relative to the axle box can be restricted by the simple configuration.

The bogie according to the second embodiment further includes stopper holding members located at both car-width-direction sides of the plate springs and fixed to the axle boxes, wherein: the stoppers extend in the car width direction; and both ends of the stoppers are held by the stopper holding members. In this case, the locked member of the plate spring receiver and the locking member of the axle box portion in the first embodiment can be omitted.

The foregoing has explained the embodiments of the present invention in reference to the drawings. However, specific configurations are not limited to these embodiments. Design changes and the like within the scope of the present invention are included in the present invention.

INDUSTRIAL APPLICABILITY

The present invention can provide a railcar bogie configured such that: a plate spring is easily attached to the railcar bogie; and the plate spring hardly falls. Therefore, the present invention is useful in a technical field of railcars.

REFERENCE SIGNS LIST