Patent Publication Number: US-9845098-B2

Title: Railcar bogie

Description:
TECHNICAL FIELD 
     The present invention relates to a bogie supporting a carbody of a railcar. 
     BACKGROUND ART 
     A bogie for supporting a carbody of a railcar and allowing the railcar to run along a rail is provided under a floor of the carbody. In the bogie, axle boxes each configured to accommodate a bearing for supporting a wheelset are supported by axle box suspensions so as to be displaceable relative to a bogie frame in an upper/lower direction. For example, in PTL 1, the bogie frame includes a cross beam extending in a lateral direction and a pair of left and right side sills respectively extending from both end portions of the cross beam in a front/rear direction. The axle boxes accommodating the bearings for the axles are supported on the bogie frame by axle beam type axle box suspensions. According to the axle beam type axle box suspension, the axle box and the side sill are coupled to each other in such a manner that a tip end portion of an axle beam projecting integrally from the axle box is elastically coupled to an attaching portion formed integrally with the side sill. 
     CITATION LIST 
     Patent Literature 
     PTL 1: Japanese Laid-Open Patent Application Publication No. 1-160777 
     SUMMARY OF INVENTION 
     Technical Problem 
     According to the bogie of PTL 1, the attaching portion to which the tip end portion of the axle beam is elastically coupled is formed integrally with the side sill. However, once the attaching portion is integrated with the side sill by welding or the like, the position of the attaching portion cannot be adjusted. Therefore, for example, an accumulated dimension error of parts which is generated when assembling the bogie may become large. On this account, producing the bogie with a high degree of accuracy requires skill. 
     An object of the present invention is to easily produce a bogie with a high degree of accuracy. 
     Solution to Problem 
     A railcar bogie according to the present invention includes: a bogie frame including a cross beam supporting a carbody of a railcar; a pair of axles respectively arranged at both sides of the cross beam in a car longitudinal direction and extending in a car width direction; bearings provided at both car width direction sides of each of the axles and rotatably supporting the axles; axle boxes respectively accommodating the bearings; and coupling devices coupling the axle boxes and the bogie frame to one another, each of the coupling devices including a first member projecting from the axle box to the bogie frame, a second member projecting from the bogie frame to the first member, and a coupling portion coupling the first member and the second member to each other, and the second member being formed separately from the bogie frame and positioned by contacting the bogie frame. 
     According to the above configuration, the second member projecting from the bogie frame toward the first members is formed separately from the bogie frame and is positioned by contacting the car width direction end portion of the bogie frame. Therefore, as compared to a case where the second member is formed integrally with the bogie frame, for example, an accumulated dimension error of the parts of the bogie can be easily adjusted. Thus, the bogie can be easily produced with a high degree of accuracy. 
     Advantageous Effects of Invention 
     As is clear from the above explanations, according to the present invention, the bogie can be easily produced with a high degree of accuracy. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view showing a railcar bogie according to an embodiment. 
         FIG. 2  is a plan view of the bogie shown in  FIG. 1 . 
         FIG. 3  is a side view of the bogie shown in  FIG. 1  (an electric motor, a reducer, and the like are not shown). 
         FIG. 4  is an enlarged side view of major portions of the bogie shown in  FIG. 3 . 
         FIG. 5  is a cross-sectional view taken along line V-V of  FIG. 4 . 
         FIG. 6  is an exploded perspective view for explaining positioning between a receiving seat unit and a cross beam in the bogie shown in  FIG. 3 , when viewed from above. 
         FIG. 7  is an exploded perspective view for explaining the positioning between the receiving seat unit and the cross beam in the bogie shown in  FIG. 3 , when viewed from below. 
         FIG. 8  is a perspective view showing the major portions of the bogie shown in  FIG. 3  (a plate spring and the like are not shown), when viewed from an obliquely lower side of an inside of the bogie. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, an embodiment will be explained in reference to the drawings. 
       FIG. 1  is a perspective view showing a railcar bogie  1  according to the embodiment.  FIG. 2  is a plan view of the bogie  1  shown in  FIG. 1 .  FIG. 3  is a side view of the bogie  1  shown in  FIG. 1 . As shown in  FIGS. 1 to 3 , the bogie  1  for a railcar includes a bogie frame  4 . The bogie frame  4  supports a carbody (not shown) via air springs  2  and a bolster  3 , the air springs  2  serving as secondary suspensions. The bogie frame  4  includes a cross beam  5 . The cross beam  5  extends in a car width direction that is a left/right direction and supports the carbody. However, unlike the configuration of a conventional railcar bogie, the bogie frame  4  does not include side sills which respectively extend from both car width direction end portions of the cross beam  5  in a car longitudinal direction that is a front/rear direction. The cross beam  5  is connected to the bolster  3  via a center plate (not shown) and a center pin (not shown) so as to be able to swivel. The bolster  3  is connected to the carbody (not shown) via the air springs  2  and bolster anchors  12 . A pair of front and rear axles  6  are respectively arranged in front of and behind the cross beam  5  so as to extend in the car width direction. Wheels  7  are respectively fixed to both car width direction sides of each axle  6 . Bearings  8  are respectively provided at both car width direction end portions of each axle  6  so as to be located outside the wheels  7  in the car width direction. The bearings rotatably support the axles  6 . The bearings  8  are respectively accommodated in axle boxes  9 . Electric motors  10  are attached to the cross beam  5 . Gear boxes  11  are respectively connected to output shafts of the electric motors  10 . Each of the gear boxes  11  accommodates reduction gears which transmit power to the axle  6 . 
     Each of plate springs  30  extending in the car longitudinal direction is provided between the cross beam  5  and the axle box  9 . Longitudinal direction middle portions  30   a  of the plate springs  30  respectively support both car width direction end portions  5   a  of the cross beam  5 . Both longitudinal direction end portions  30   b  of each of the plate springs  30  are respectively supported by the axle boxes  9 . To be specific, each of the plate springs  30  serves as both a primary suspension and a conventional side sill. The middle portions  30   a  of the plate springs  30  are arranged under the cross beam  5 . Pressing members  31  are respectively provided under the car width direction end portions  5   a  of the cross beam  5 . Each of the pressing members  31  is provided between a pair of receiving seats  17  and  18  described below and has a circular-arc lower surface. The pressing members  31  are respectively disposed on the middle portions  30   a  of the plate springs  30  from above so as to respectively, freely contact the middle portions  30   a . To be specific, the pressing members  31  respectively contact upper surfaces of the plate springs  30  by a downward load from the cross beam  5  due to gravity so as not to fix the plate springs  30  in the upper/lower direction. 
     Spring seats  33  are respectively attached to upper portions of the axle boxes  9 . The end portions  30   b  of the plate springs  30  are respectively disposed on the spring seats  33  from above so as to respectively, freely contact the spring seats  33 . Each of the spring seats  33  includes an inclined member  34 , a gap body  35 , and a receiving member  36 . The inclined member  34  is positioned on the axle box  9 , and an upper surface of the inclined member  34  is inclined toward a longitudinal direction middle side. The gap body  35  is positioned on the inclined member  34  and has elasticity. The receiving member  36  is positioned on the gap body  35 , and the end portion  30   b  of the plate spring  30  is placed on the receiving member  36 . Upper surfaces of the end portions  30   b  of each of the plate springs  30  are inclined in a direction toward the middle portion  30   a . The middle portion  30   a  of the plate spring contacts a lower surface of the pressing member  31  and has a circular-arc shape. To be specific, the middle portion  30   a  is located under the end portions  30   b , and the entire plate spring  30  has a bow shape that is convex downward in a side view. 
     The axle boxes  9  are coupled to the car width direction end portions  5   a  of the cross beam  5  by coupling devices  15  serving as axle box suspensions. Each of the coupling devices  15  includes axle beams  16  (first members), a receiving seat unit  20  (second member), and coupling portions  19 . Each of the axle beams  16  projects integrally from the axle box  9  toward the cross beam  5 . The receiving seat unit  20  projects from the cross beam  5  toward the axle beams  16 . Each of the coupling portions  19  couples a tip end portion  16   a  of the axle beam  16  to the receiving seat unit  20 . To be specific, the coupling device  15  of the present embodiment is an axle beam type device. A part of the plate spring  30  is arranged at a position overlapping the receiving seat unit  20  in a side view. The plate spring  30  is arranged so as to be spaced apart from the receiving seat unit  20 . The plate spring  30  extends through a space between the receiving seats  17  and  18  of the receiving seat unit  20  to a position under the cross beam  5 . 
       FIG. 4  is an enlarged side view of major portions of the bogie  1  shown in  FIG. 3 .  FIG. 5  is a cross-sectional view taken along line V-V of  FIG. 4 .  FIG. 6  is an exploded perspective view for explaining positioning between the receiving seat unit  20  and the cross beam  5  in the bogie  1  shown in  FIG. 3 , when viewed from above.  FIG. 7  is an exploded perspective view for explaining the positioning between the receiving seat unit  20  and the cross beam  5  in the bogie  1  shown in  FIG. 3 .  FIG. 8  is a perspective view showing major portions of the bogie  1  shown in  FIG. 3 , when viewed from an obliquely lower side of an outside of the bogie. As shown in FIGS.  3  to  8 , the receiving seat unit  20  is located under the end portion  5   a  of the cross beam  5  and extends in the car longitudinal direction (a thick line in each of  FIGS. 3 and 4  shows the outline of the receiving seat unit  20 ). The receiving seat unit  20  is formed separately from the cross beam  5  and is not fixed to the cross beam  5  by welding. The receiving seat unit  20  contacts the cross beam  5  and is positioned by the cross beam  5 . The receiving seat unit  20  includes the receiving seats  17  and  18  and a connecting plate  24 . The receiving seats  17  and  18  are a pair of vertical plates and located under the end portion  5   a  of the cross beam  5 . The receiving seats  17  and  18  extend in the car longitudinal direction and are arranged so as to be spaced apart from each other in the car width direction. The connecting plate  24  is a horizontal plate and is joined to the receiving seats  17  and  18  so as to couple the receiving seats  17  and  18  to each other. 
     As shown in  FIGS. 3 and 4 , a lower portion of each of the receiving seats  17  and  18  is thicker than an upper portion of each of the receiving seats  17  and  18 . Both longitudinal direction end portions  17   b  of the receiving seat  17  respectively project toward the axle beams  16  (axle boxes  9 ) respectively located at both car longitudinal direction sides of the cross beam  5 , and both longitudinal direction end portions  18   b  of the receiving seat  18  respectively project toward the axle beams  16  (axle boxes  9 ) respectively located at both car longitudinal direction sides of the cross beam  5 . One of the end portions  17   b  of the receiving seat  17  is coupled to one of the axle beams  16 , and the other end portion  17   b  of the receiving seat  17  is coupled to the other axle beam  16 . One of the end portions  18   b  of the receiving seat  18  is coupled to one of the axle beams  16 , and the other end portion  18   b  of the receiving seats  18  is coupled to the other axle beam  16 . Specifically, as shown in  FIG. 5 , a tubular portion  21  is provided at the tip end portion  16   a  of the axle beam  16 . An inner peripheral surface of the tubular portion  21  has a cylindrical shape, and both car width direction sides of the tubular portion  21  are open. A bobbin-shaped core rod  23  is inserted through an internal space of the tubular portion  21  via a rubber bushing  22 . Fitting grooves  17   a  are respectively formed at both longitudinal direction end portions of the receiving seat  17  so as to be open downward. Fitting grooves  18   a  are respectively formed at both longitudinal direction end portions of the receiving seat  18  so as to be open downward. The core rod  23  includes protruding portions  23   a . The protruding portions  23   a  respectively project toward both car width direction sides and each has a semi-circular cross section. The protruding portions  23   a  are respectively fitted in the fitting grooves  17   a  and  18   a  from below. In this state, a lid member  25  is fixed to lower end surfaces of the receiving seats  17  and  18  by bolts (not shown) form below so as to close the lower openings of the fitting grooves  17   a  and  18   a . Thus, the core rod  23  is supported by the lid member  25  from below. To be specific, the protruding portions  23   a  of the core rod  23 , the fitting grooves  17   a  and  18   a  of the receiving seats  17  and  18 , and the lid member  25  constitute the coupling portion  19 . 
     As shown in  FIGS. 6 and 7 , the connecting plate  24  of the receiving seat unit  20  includes a base plate portion  24   a  and a projecting plate portion  24   b . The base plate portion  24   a  extends between upper ends of the receiving seats  17  and  18 . The projecting plate portion  24   b  projects from the base plate portion  24   a  toward a car width direction inner side. The base plate portion  24   a  is shorter than each of the receiving seats  17  and  18  in the car longitudinal direction. The projecting plate portion  24   b  is longer than the base plate portion  24   a  in the car longitudinal direction. The projecting plate portion  24   b  includes a portion contacting a car width direction inner side surface of the receiving seat  18  located at the car width direction inner side. A fitting portion  24   c  is formed on an upper surface of the base plate portion  24   a . The fitting portion  24   c  is a convex portion projecting upward. A fitted portion  5   e  is formed on a lower surface of the cross beam  5 , the lower surface being opposed to the fitting portion  24   c . The fitted portion  5   e  is a concave portion in which the fitting portion  24   c  is fitted. A plurality of bolt holes  24   d  are formed on the projecting plate portion  24   b . A plurality of bolt hole  5   d  are formed on positions of the cross beam  5 , the positions respectively overlapping the bolt holes  24   d . The receiving seat unit  20  is attached to the cross beam  5  in such a manner that: the fitting portion  24   c  is positioned by being fitted in the fitted portion  5   e ; and bolts (not shown) are fastened to the bolt holes  24   d  and  5   d . The pressing member  31  (see  FIG. 3 ) placed on the middle portion  30   a  of the plate spring  30  from above is attached to a lower surface of the base plate portion  24   a.    
     As shown in  FIGS. 4 to 7 , a pair of brackets  5   c  project from each of both car longitudinal direction side surfaces (front and rear surfaces) of the cross beam  5 . The brackets  5   c  are provided with pin holes  5   f  each having an axis extending in the car width direction. Bracket portions  17   e  are integrally formed at the receiving seat  17  and respectively provided with pin holes  17   f  each having the same axis as the pin hole  5   d . Bracket portions  18   e  are integrally formed at the receiving seat  18  and respectively provided with pin holes  18   f  each having the same axis as the pin hole  5   f . Pins  28  are inserted into the pin holes  5   f  of the brackets  5   c  and the pin holes  17   f  and  18   f  of the bracket portions  17   e  and  18   e . Each of the pins  28  includes a shaft portion  28   a , a head portion  28   b , and a through hole  28   c . The shaft portion  28   a  does not have screw threads. The head portion  28   b  is formed at one of end portions of the shaft portion  28   a . The through hole  28   c  is formed at the other end portion of the shaft portion  28   a  so as to extend in a direction perpendicular to an axial direction of the pin  28 . A retaining pin  29  is attached to the through hole  28   c . The bracket  5   c  of the cross beam  5  is arranged between the bracket portion  17   e  of the receiving seat  17  and the bracket portion  18   e  of the receiving seat  18  and is spaced apart from the bracket portion  17   e  of the receiving seat  17  and the bracket portion  18   e  of the receiving seat  18 . To be specific, the pin  28  allows relative axial movements between the bracket  5   c  of the cross beam  5  and each of the bracket portions  17   e  and  18   e  of the receiving seats  17  and  18 . A gap between the bracket  5   c  and the receiving seat  18  in the car width direction is smaller than a gap between the plate spring  30  and the receiving seat  17  or  18  in the car width direction and is also smaller than a gap between the tip end portion  16   a  of the axle beam  16  and the receiving seat  17  or  18  in the car width direction. 
     As shown in  FIG. 8 , the lid member  25  constituting the coupling portion  19  includes a pair of lid portions  25   a  and a bridge portion  25   b . The lid portions  25   a  are respectively fixed to lower surfaces of the receiving seats  17  and  18  by bolts to close the lower openings of the fitting grooves  17   a  and  18   a . The bridge portion  25   b  connects the lid portions  25   a  to each other so as to avoid the tip end portion  16   a  of the axle beam  16 . A bottom plate member  26  is provided at a car longitudinal direction middle side of the lid member  25  and fixed to the lower surfaces of the receiving seats  17  and  18  by bolts so as to extend between the receiving seats  17  and  18 . The lid member  25  and the bottom plate member  26  are located under the plate spring  30 . 
     According to the configuration explained above, the receiving seat unit  20  projecting from the cross beam  5  toward the axle beams  16  is formed separately from the cross beam  5  and is positioned by contacting the car width direction end portion  5   a  of the cross beam  5 . Therefore, as compared to a case where the receiving seat unit  20  is formed integrally with the bogie frame  5  by welding, for example, an accumulated dimension error of the parts of the bogie  1  can be easily adjusted. Thus, the bogie  1  can be easily produced with a high degree of accuracy. 
     The receiving seats  17  and  18  of the receiving seat unit  20  are located under the cross beam  5 , extend in the car longitudinal direction, and realize both the coupling to the axle beam  16  located at one of car longitudinal direction sides and the coupling to the axle beam  16  located at the other car longitudinal direction side. Therefore, dimensional accuracy of the axle beams  16  at front and rear sides improves, and the number of parts and assembling man-hours can be reduced. The cross beam  5  and the receiving seats  17  and  18  are coupled to each other by the pins  28 . Therefore, at the time of an abnormality such as derailment, the receiving seats  17  and  18  which are formed separately from the cross beam  5  can be prevented from being separated from the cross beam  5 . 
     The fitting portion  24   c  of receiving seat unit  20  is fitted in the fitted portion  5   e  of the cross beam  5  in the upper/lower direction. Therefore, the receiving seat unit  20  can be easily positioned relative to the cross beam  5  in the horizontal direction. Regarding the receiving seat unit  20 , not the base plate portion  24   a  located between the receiving seats  17  and  18  but the projecting plate portion  24   b  projecting toward one side is fastened to the cross beam  5  by the bolts. Therefore, in a state where the plate spring  30  is arranged between the receiving seats  17  and  18 , the receiving seat unit  20  can be attached by attaching the bolts and can be detached by detaching the bolts. The plate spring  30  is provided at a position sandwiched between the receiving seats  17  and  18  and overlaps the receiving seats  17  and  18  in a side view. Therefore, the bogie  1  can be reduced in size in the upper/lower direction. 
     The present invention is not limited to the above embodiment. Modifications, additions, and eliminations may be made within the scope of the present invention. The present embodiment has explained the bogie  1  which does not include the side sills but includes the plate springs  30 . However, a bogie including side sills may be adopted. The present embodiment has explained the axle beam type coupling device as the coupling device  15 , but the coupling device of the other type may be adopted. 
     INDUSTRIAL APPLICABILITY 
     As above, the railcar bogie according to the present invention has the above-described excellent effects. It is useful to widely apply the present invention to railcar bogies which can achieve the significance of these effects. 
     REFERENCE SIGNS LIST 
       1  bogie 
       4  bogie frame 
       5  cross beam 
       5   b  fitting portion 
       5   c  bracket 
       5   d  pin hole 
       5   e  fitted portion 
       6  axle 
       8  bearing 
       9  axle box 
       15  coupling device 
       16  axle beam (first member) 
       17 ,  18  receiving seat 
       17   e ,  18   e  bracket portion 
       17   f ,  18   f  pin hole 
       19  coupling portion 
       20  receiving seat unit (second member) 
       24   c  fitting portion 
       28  pin 
       30  plate spring