The present invention relates to a railroad vehicle provided with a low roof structure.
A railroad vehicle is generally provided with a roof structure which constitutes the top of a vehicle body. In terms of restrictions of construction gauges and exterior designs, structures have been known, where an air conditioner or the like can be mounted by lowering the roof structure so that it is recessed toward a vehicle cabin from the external surface of the roof structure (refer to Patent Document 1). Hereinafter, the structural part which is lowered from other parts of the roof structure is referred to as a “low roof structure.” The low roof structure disclosed in Patent Document 1 is made of an extruded aluminum alloy, which is comprised of a flat part on which the air conditioner is placed and rising parts which rise from both sides of the flat part in a width direction to join to side structures. The flat part is joined to the respective rising parts by welding or friction stir welding. Thus, in Patent Document 1, a reduction in strength and a reduction in a noise generation caused by the joining parts can be prevented, while facilitating an installation work.
Meanwhile, since a large load or the like is less likely applied to the low roof structure itself, it is ideal to form the low roof structure into a thin-plate structure also in terms of reducing the entire weight of the railroad vehicle. However, since the low roof structure of Patent Document 1 uses a section bar material having a uniform cross section and is entirely thick, there is an inconvenience of becoming the trouble of the weight reduction. Further, since the roof structure is exposed to rain and wind, waterproofing or the like is required when using the low roof structure where the air conditioner or the like is placed. However, Patent Document 1 does not propose any waterproofing for the low roof structure. Thus, the purpose of the present invention is to provide a railroad vehicle with a low roof structure, particularly a low roof structure which can reduce the entire weight of the railroad vehicle and has a waterproof structure.
A railroad vehicle according to the present invention has a roof. An air conditioner is installable in an upper part of the roof. The railroad vehicle includes a roof structure having an opening, a low roof main body, provided in the opening and having at least one of a recessed part recessed in a cross section and a placing part where a pass hole is formed in a plan view, the air conditioner being able to be placed on an edge part of the at least one of the recessed part and the pass hole of the placing part, and an edge part of the low roof main body, continuously formed from the low roof main body and joined to the roof structure. The low roof main body and the edge part of the low roof main body are made of plastic. Note that the term “plastic” as used herein includes fiber-reinforced plastics, such as CFRP and GFRP, and various composite materials. According to the configuration, the weight of the low roof structure, that is, the entire weight of the railroad vehicle can be reduced by forming the low roof main body and its edge part from plastic. In addition, since the low roof main body and its edge part are made of plastic, even if the low roof main body has a complicated three-dimensional shape, dealing with this is easy.
According to the present invention, the railroad vehicle provided with the low roof structure which can reduces the weight of the low roof structure, that is, the entire weight of the railroad vehicle, while having the waterproof structure, can be provided.
a) to (c) are enlarged views of a section D of
1-1. Outline of Entire Configuration
1-2. Configuration of Low Roof Main Body
1-3. Mounting Structure of Low Roof Main Body and Roof Structure
1-4. Waterproof Construction of Low Roof Structure
1-5. Method of Fitting Low Roof Main Body
As illustrated in
As illustrated in
As illustrated in
Note that, as illustrated in
Next, a mounting structure of the low roof main body 20 and the roof structure 1 is described. As illustrated in
With the above configuration, the reinforced-plastic edge part 22 of the low roof main body 20 will not be damaged by heat of welding. In addition, the circumferential surface of the stem portion 80 of the rivet 8 closely contacts the circumferential surfaces of both the through-holes 24 and 60 when the rivet 8 is caulked. Thus, even if a shearing load is applied to the low roof structure 2 while the vehicle is traveling, since the shearing load is received by the entire circumferential surface of the stem portion 80 of the rivet 8, a joining strength against the shearing load between the frame 6 and the low roof main body 20 can be increased. Further, as illustrated in
Next, a waterproof structure of the low roof structure is described. As illustrated in
That is, as illustrated in
When attaching the low roof main body 20 to the roof structure 1, the frame 6 is attached to the roof structure 1 in advance by welding. Then, the low roof main body 20 may be inserted into the first opening 10 from above the first opening 10 to join the frame 6 to the edge part 22 of the low roof main body 20 by the rivets 8. However, the rivets 8 used for joining the frame 6 to the edge part 22 of the low roof main body 20 will actually be hundreds in total number. Thus, in a case where the edge part 22 of the low roof main body 20 is placed on the frame 6 of the roof structure 1, caulking the hundreds of rivets 8 to join the frame 6 to the edge part 22 is a lot of work and, thus, workability is bad. In addition, as described above, although the sealant is applied to the circumferential surfaces of the head portions 81 of the rivets 8, the workability is bad because the sealant must be applied from above the roof structure 1. Because of the badness of the workability, the application of the sealant tends to be non-uniform and, thus, this may cause a trouble in the durability of the sealant as well. Therefore, in this embodiment, the low roof main body 20 is attached to the roof structure 1 by the following procedures.
First, in a process which is different from the process of attaching the low roof main body 20 to the roof structure 1 (for example, a CFRP forming process) the frame 6 is arranged beneath the edge part 22 of the low roof main body 20. The second through-holes 60 are aligned with the first through-holes 24, and the stem portions 80 of the rivets 8 are then inserted from above the edge part 22 of the low roof main body 20 into both the respective through-holes 24 and 60. Next, the bottom end parts of the stem portions 80 of the rivets 8 are caulked to join the frame 6 to the edge part 22 of the low roof main body 20. Then, coating of the sealant is applied to the circumferential surfaces of the head portions 81 of the rivets 8. The low roof main body 20 to which the frame 6 is attached is inserted from above the first opening 10 into the first opening 10. Thus, the frame 6 contacts the edge part 22 of the first opening 10 of the roof structure 1. Then, the frame 6 is attached to the roof structure 1 by welding. By doing so, since the frame 6 can be attached to the edge part 22 of the low roof main body 20 in an exclusive factory, the rivets 8 can be caulked by an automated machine, without human labors. Therefore, the workability becomes better. In addition, since workability also becomes better in the sealant application work, this work can be carried out with high accuracy.
Next, the air conditioner 5 is accommodated in the recessed part 3, and the leg part 51 of the air conditioner 5 is placed on the upper surface of the protrusion 45. Here, alignment protrusions 46 may be formed on the protrusion 45, fitting holes 52 into which the alignment protrusions 46 are fitted may also be formed in a lower surface of the leg part 51, and the alignment protrusions 46 may be provided in the fitting holes 52 (refer to
In this modification, since the recessed part 3 is not formed, the entire weight of the low roof main body 20, that is, the entire weight of the roof structure 1 can further be reduced. In addition, by not forming the recessed part 3, a certain height of the passenger cabin ceiling within the range of the low roof section of the vehicle structure can be secured, and it becomes easier to obtain a sufficient vehicle interior space, compared with the case where the recessed part 3 is formed. Note that, although not illustrated in
Next, modifications of the waterproof structure of the low roof structure and the installation of the air conditioner 5 will be described. Since other configurations are similar to the configurations of the above embodiment, description thereof is omitted.
In the above embodiment, although the frame 6 is joined to the edge part 22 of the low roof main body 20 with the rivets 8, they may also be joined with adhesives. Alternatively, when forming the low roof main body 20 by autoclave fabrication or fusion fabrication, a co-bond method in which the frame 6 is simultaneously pasted together may also be adopted. In these cases, the application of the sealant onto the head portions 81 of the rivets 8 which is performed when the rivets 8 are used is unnecessary. However, since the frame 6 is joined to the roof structure 1 by welding as described above, heat caused by the welding may be transferred to the edge part 22 of the low roof main body 20 to damage the adhesives and the edge part 22 itself. Particularly, if the contacting area between the frame 6 and the edge part 22 of the low roof main body 20 is large, the quantity of heat caused by the welding and transferred to the edge part 22 of the low roof main body 20 is also large.
Therefore, in such a case, the frame 6 is to be welded to the roof structure 1 by low-heat-input welding, such as laser welding, laser arc hybrid welding, or CMT (Cold Metal Transfer). Thus, the quantity of heat caused by the welding and transferred to the edge part 22 of the low roof main body 20 at the time of welding can be reduced, and the damages to the adhesives or the edge part 22 itself can also be reduced. Of course, when joining the frame 6 to the edge part 22 of the low roof main body 20 with the rivets 8, the low-heat-input welding may also be used for welding the frame 6 to the roof structure 1.
Further, the frame 6 may be joined to the edge part 22 of the low roof main body 20 by using bolts. Alternatively, they may be joined using various combinations, such as rivets and adhesives, or bolts and adhesives. Note that, alternatively to the above embodiment, a sandwich structure where the peripheral wall 30 may be comprised of face plates and a core member. Further, in the above embodiment, although CFRP or GFRP are used as one example, the material may be, but not limited to, other reinforced plastics. Further, in the above embodiment, the leg part 51 of the air conditioner 5 is placed on the flat part 40. However, alternatively to this configuration, a spacer (not illustrated) may be provided to the bottom portion 31 of the recessed part 3, and the bottom of the air conditioner 5 may be placed on the spacer.
In each of the embodiments, the roof structure has the metal frame extending toward the opening, and the frame is joined to the roof structure and the edge part of the low roof main body. With this configuration, the frame can be joined to the roof structure by welding and, thus, the workability is good. In each of the embodiments, the roof structure has the metal frame extending toward the opening, and the frame is joined to the edge part of the low roof main body by the rivets or the adhesives. With this configuration, since the frame can be joined in advance to the edge part of the low roof main body which is made of reinforced plastic with the rivets or the adhesives, the workability, quality, and strength of the joining of both can be improved.
In each of the embodiments, the roof structure has the metal frame extending toward the opening, the upper surface of the frame is joined at one end to the lower surface of the edge part of the low roof main body, and the lower surface of the frame is joined at the other end to the upper surface of the roof structure. With this configuration, since the edge part of the low roof main body, the frame, and the roof structure are arranged descending in a stepwise toward the outside, and they are inclined downwardly toward the outside in the vehicle width direction, the rain water and the like will not be accumulated at the fitting part between the edge part and the frame, or the fitting part between the frame and the roof structure. In addition, even if the frame and the edge part which are joined together come off apart, the low roof main body will not fall. In each of the embodiments, the roof structure has the metal frame extending toward the opening, one end of the frame is joined to the edge part of the low roof main body, and the other end of the frame is joined to the roof structure by the low-heat-input welding. With this configuration, since the frame is joined to the roof structure by the low-heat-input welding, the edge part of the low roof main body made of reinforced plastic does not deteriorate by the heat of welding.
In each of the embodiments, the low roof main body further has the stepped part including the placing part inside the edge part of the low roof main body, and the placing part of the stepped part includes the protrusion extending upward in the vertical direction. Further, the draining holes are formed between the protrusion and the edge part of the low roof main body. With this configuration, even if the rain water enters through the edge part of the low roof main body, the rain water is dammed up by the protrusion and, thus, the rain water is prevented from entering into the recessed part or the air conditioner. In addition, the rain water can be discharged outside the roof structure via the draining holes. Although the protrusion can also be used as an attachment base of the air conditioner, the configuration of the attachment base can be made simpler if the protrusion which achieves the waterproof function is separately formed from the attachment base of the air conditioner. With this configuration, the stepped part and the protrusion can be integrally formed. In addition, since the protrusion can also be formed into the sandwich structure, sufficient strength can be secured.
In each of the embodiments, the bottom of the recessed part has the sandwich structure having the two face plates made of reinforced plastic and the core member formed between the face plates. In addition, the core member may also be formed in a honeycomb structure or may also be made of foamed resin. With this configuration, sufficient strength can be secured while reducing the weight, compared with the case where the bottom of the recessed part is entirely made of metal. In each of the embodiments, the bottom of the recessed part has the corrugated-plate structure made of reinforced plastic where the ridge portions and the valley portions are continuously formed in the vehicle width direction. With this configuration, sufficient strength can be secured while reducing the weight, compared with the case where the bottom of the recessed part is entirely made of metal. In addition, since it can have the thin-plate structure, the sufficient ceiling height of the passenger cabin can be obtained.
In each of the embodiments, the cover member which covers the upper part of the low roof main body is further provided, and the bottom surface of the end part of the cover member is placed on the top surface of the end part of the recessed part of the edge part of the low roof main body via the sealing member. With this configuration, waterproof performance can be secured, while the cover member can easy be detachable from the low roof main body. According to the above description, many improvements and other embodiments of the present invention are apparent for the person skilled in the art. Therefore, the above description is intended to be interpreted only as illustration, and it is to provide in order to teach the person skilled in the art one mode for carrying out the present invention. Details of the structures and/or the functions can be substantially changed without departing from the scope of the present invention.
The present invention is useful if it is applied to the railroad vehicle provided with the low roof structure.
Number | Date | Country | Kind |
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2012-037019 | Feb 2012 | JP | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP2013/001074 | 2/25/2013 | WO | 00 | 4/14/2014 |