JP7623248B2 - Manufacturing method of rail vehicle body - Google Patents

Description

The present invention relates to a method for manufacturing a rail vehicle structure.

A railway car has a hexahedral railway car structure consisting of an underframe that forms the floor surface, side structures erected at both ends of the underframe in the width direction, end structures erected at both ends of the underframe in the longitudinal direction, and a roof structure placed on the upper ends of the side structures and end structures. In general, iron-based stainless steel plates have excellent weather resistance and corrosion resistance, but they also have the disadvantage of being relatively heavy. Therefore, to compensate for the disadvantages of stainless steel plates, railway car structures have been developed that combine stainless steel exterior plates with main parts made of aluminum alloy, which has a relatively low specific gravity, to provide strength.

Patent Document 1 discloses a method for manufacturing a railway car body structure by friction stir welding a stainless steel plate to an aluminum alloy extrusion. According to this technology, an aluminum alloy extrusion hollow shape is friction stir welded from the inside of the car, and a stainless steel plate is friction stir welded from the inside of the car to the butt joint of the hollow shape on the outside of the side structure, thereby forming the side structure of the car body.

JP 2008-55498 A

In general, the thickness of the components that make up the rail vehicle body structure used in high-speed railway cars and the like is reduced to reduce weight. However, as a result of the emphasis on weight reduction, noise from outside the vehicle can easily penetrate the roof structure, side structure, and underframe that make up the hexahedral structure of the rail vehicle and enter the interior of the vehicle, and this can be perceived as transmitted sound, causing discomfort to passengers.

The present invention was made in consideration of the above-mentioned problems, and aims to provide a method for manufacturing a rail car body structure that is highly reliable, lightweight, and has a large transmission loss that can effectively suppress the intrusion of transmitted sound into the car interior.

In order to solve the above problems, one representative method for manufacturing a railway car body structure according to the present invention is as follows:
A frame forming the floor surface;
Side structures erected at both ends in a width direction of the frame;
An upper floor panel that constitutes the underframe;
A method for manufacturing a railway vehicle structure having
The side structure includes:
a ferrous face plate formed from a ferrous material;
an aluminum-based frame member that is placed on the vehicle interior side of the iron-based panel and is made of an aluminum-based material;
It has
The aluminum-based frame member has a top hat-shaped cross section intersecting a longitudinal direction of the aluminum-based frame member and has a pair of edges,
The iron-based face plate and the edge portion are brought into close contact with each other,
When a friction stir welding tool is brought into contact with the aluminum-based frame member from the side of the portion of the aluminum-based frame member that is in close contact with the steel-based face plate and the aluminum-based frame member, and the tool is rotated around its axis while moving the tool so as to overlap the welding lines, the steel-based face plate and the aluminum-based frame member are friction-stir-welded to each other,
While rotating the tool around a counterclockwise axis, the tool is advanced along a first direction to form a first weld line by friction stir welding the edge portion to the ferrous face plate;
While rotating the tool counterclockwise, the tool is advanced along a second direction opposite to the first direction while viewing the first welding line to the left of the traveling direction of the tool, thereby forming a second welding line by friction stir welding the edge portion to the iron-based face plate;
This is achieved by overlapping a part of the first weld line and a part of the second weld line in the width direction of the aluminum-based frame member so that a hooking defect caused by the friction stir welding that forms the first weld line overlaps with a hooking defect caused by the friction stir welding that forms the second weld line.

According to the present invention, it is possible to provide a manufacturing method for a railway vehicle body structure that is highly reliable, lightweight, and has a body structure with a large transmission loss that can effectively suppress the intrusion of transmitted sound into the vehicle interior.
Problems, configurations and effects other than those described above will become apparent from the following description of the embodiments.

FIG. 1 is a side view of a railroad vehicle. FIG. 2 is a cross-sectional view (cross-section AA in FIG. 1) intersecting the longitudinal direction of the railway vehicle. FIG. 3 is a cross-sectional view (part B in FIG. 2) intersecting the longitudinal direction of the side structure of the railway vehicle. FIG. 4 is a cross-sectional view (cross-section DD in FIG. 3) intersecting in the height direction of the side structure of the railway vehicle. FIG. 5 is a schematic diagram (view taken along the arrow C in FIG. 3) showing a process for manufacturing a side structure of a railway vehicle. FIG. 6 is a cross-sectional view of one edge of the frame member immediately after it has been joined at one joining line, in the process of joining the frame member to the vehicle exterior panel. FIG. 7 is a cross-sectional view of the other edge of the rib member immediately after the other edge of the rib member is joined at two joining lines in the process of joining the rib member to the vehicle exterior panel. FIG. 8 is a schematic top view showing the configuration of the upper floor panel. FIG. 9 is a cross-sectional view of the upper floor panel (cross-section G-G in FIG. 8). FIG. 10 is a flow chart showing the process of joining the side structure and the upper floor panel.

Below, an embodiment of the present invention will be described with reference to the drawings. First, the directions used in the description will be defined. The longitudinal direction of the rail vehicle or the rail direction is the x-direction, the width direction of the rail vehicle or the sleeper direction is the y-direction, and the height direction of the rail vehicle is the z-direction, which will be referred to simply as the x-direction, y-direction, and z-direction below.

Rail vehicles are vehicles that run along laid tracks, and include railway cars, monorail cars, trams, new transit cars, etc. As a representative example of rail vehicles, an embodiment of the present invention will be explained using railway cars. In this specification, "iron-based material" refers to a material that contains at least Fe, and preferably also C. In addition, "aluminum-based material" refers to a material that contains at least Al.

Figure 1 is a side view of a railway vehicle, and Figure 2 is a cross-sectional view (cross-section A-A in Figure 1) intersecting the longitudinal direction of the railway vehicle. The railway vehicle 1 has a hexahedral structure 3, and both ends of the structure 3 in the x direction are supported by bogies 2 having wheels that roll on tracks (rails) 90.

The structure 3 is a hexahedron consisting of an underframe 7 forming the floor surface, side structures 6 erected at both ends of the underframe 7 in the y direction, end structures 9 erected at both ends of the underframe 7 in the x direction, and a roof structure 5 placed on the upper ends (ends in the z direction) of the side structures 6 and end structures 9. A partition wall 69 is provided approximately parallel to the end structure 9, separating the deck section, which has an entrance where passengers get on and off, from the passenger compartment where the seats are located, and the partition wall 69 is provided with a partition door 76 for the movement of passengers, etc.

The structure 3 connects a pair of side structures 6 extending in the y direction at a height position approximately equal to the height of the platform 92, and has multiple cross beams 12 that are provided discretely along the x direction. An upper floor panel 72 is provided above the cross beams 12 via support members (not shown), and seats 70 and the like are placed on the upper surface of the upper floor panel 72. Various electrical equipment such as the bogie 2, transformer, main circuit equipment, auxiliary power supply unit, and air compressor are provided below the cross beams 12 that support the upper floor panel 72 and constitute the underframe 7.

Figure 3 is a cross-sectional view (part B in Figure 2) intersecting the longitudinal direction of the side structure of the railway vehicle, and Figure 4 is a cross-sectional view (section D-D in Figure 3) intersecting the height direction of the side structure of the railway vehicle. Since the roof structure 5 and the side structure 6 are basically of the same configuration, the configuration of the side structure 6 will be explained as a representative example while referring to Figures 3 to 7, and an explanation of the roof structure 5 will be omitted.

The side structure 6 is composed of an exterior panel 6a and a bone member (pillar) 6b that supports the exterior panel 6a from the inside of the vehicle. The bone member 6b is a top hat-shaped member with a cross-sectional shape intersecting the z-direction, that is, a pair of plate-shaped edges 6bh extend oppositely from both side edges of a main body with a U-shaped cross section. The pair of edges 6bh that make up the bone member 6b are placed in contact with the exterior panel 6a and then connected to the interior surface of the exterior panel 6a by friction stir welding using a method described below.

Figure 5 is a schematic diagram (viewed from the C arrow in Figure 3) showing the process of manufacturing the side structure of a railway vehicle. The schematic diagram showing the manufacturing process of the side structure 6 shown in Figure 5 shows the process of positioning the frame member 6b on the inner surface (upper surface) of the car exterior panel 6a placed on a surface plate, and then connecting the frame member 6b to the car exterior panel 6a by friction stir welding.

Although not shown, the tool T used for friction stir welding has a coaxial two-stage cylindrical shape with a cylindrical small diameter section at the tip of the large diameter section and coaxial with the axis of the large diameter section. The small diameter section of the tool T is embedded inside the edge section 6bh of the bone member 6b while rotating around its axis, and the end face of the large diameter section of the tool T is positioned on the upper surface of the edge section 6bh. In the process of moving along the longitudinal direction of the edge section 6bh at a predetermined feed speed (joining speed), the bone member 6b is joined to the vehicle exterior panel 6a. Along the trajectory of the movement of the tool T, a joining line L1 (L2) is generated as described below.

<Production method>
Fig. 6 is a cross-sectional view of the edge of the bone member immediately after one edge of the bone member is joined with one joining line during the process of joining the bone member to the vehicle exterior panel. Fig. 7 is a cross-sectional view of the edge of the bone member immediately after the other edge of the bone member is joined with two joining lines during the process of joining the bone member to the vehicle exterior panel. One edge 6bh shown in Fig. 6 is also joined with two joining lines, like the other edge 6bh, but in order to explain the problems in joining and the process of solving the problems, a cross-sectional view immediately after joining with only one joining line L1 is shown as a comparative example.

Figure 6 shows a schematic diagram of the process of joining one edge 6bh to the vehicle exterior panel 6a while advancing the tool T, which rotates in a counterclockwise direction 32 when viewed from above, in the x direction. At this time, in a cross section of the friction stir weld that intersects the x direction, when facing the direction of travel 30 of the tool T, a hooking defect F1 may occur on the left side of the direction of travel of the tool T (the side in the +y direction, where the direction of rotation 32 of the tool T and the direction of travel 30 of the tool T are opposite). This hooking defect F1 occurs because the joint between the edge 6bh and the vehicle exterior panel 6a is not stirred sufficiently, and therefore, although they are joined, they often do not meet the required joint strength.

Therefore, when a force acts in a direction to peel the edge 6bh away from the vehicle exterior panel 6a, there is a risk that the two will separate from each other, starting from a hooking defect F1 on the edge of the edge 6bh on the left side of the joining line L1 in the direction of travel (+y direction). The problem caused by the hooking defect F1 can be solved by friction stir welding the frame member 6b to the vehicle exterior panel 6a in such a way that one edge of the joining line L1 partially overlaps with the joining line L2, as shown in Figure 7.

A method for solving the above problem will be described in detail. First, the tool T is rotated counterclockwise and advanced in the +x direction (first direction) to friction stir weld the bone member 6b to the vehicle exterior panel 6a, forming a weld line L1. Next, the same tool T is rotated counterclockwise and advanced in the -x direction (second direction) while viewing the weld line L1 to the left of the direction of travel of the tool T, to friction stir weld the bone member 6b to the vehicle exterior panel 6a, forming a weld line L2. At this time, the bone member 6b is friction stir welded to the vehicle exterior panel 6a so that a portion of the weld line L2 in the width direction overlaps a portion of the weld line L1. It is preferable that the weld line L2 and the weld line L1 overlap over the entire longitudinal direction.

By friction stir welding the bone member 6b to the vehicle exterior panel 6a along the offset weld lines L1 and L2 using the above-mentioned method, the hooking Fl formed on the edge of the weld line L1 in the +y direction and the hooking defect F2 formed on the edge of the weld line L2 in the -y direction overlap. Therefore, when the weld line F1 and the weld line L2 are viewed macroscopically as a single weld line, we can arrange welded parts with stable joint strength on the edge of the weld line in the +y direction and the edge of the weld line in the -y direction (on both sides of the weld line).

Therefore, even if a force is applied in a direction that pulls the frame member 6b away from the vehicle exterior panel 6a, neither side of the joining line seen macroscopically is likely to become the starting point for separation, so the frame member 6b can be firmly connected to the vehicle exterior panel 6a.

If the frame members 6b are made of a lightweight alloy such as aluminum, and the car exterior panel 6a is made of a stainless steel plate (iron-based plate) that has high strength and corrosion resistance and weather resistance, the weight of the entire side structure 6 can be reduced compared to when it is made entirely of stainless steel plate. On the other hand, by placing a material with a large mass on the car exterior panel 6a, it is possible to impart a large transmission loss to the side structure 6, thereby reducing the outside noise that penetrates the side structure 6 and enters the car interior. Therefore, according to this embodiment, it is possible to provide a rail car structure that is highly reliable and lightweight, yet has a large transmission loss that can suppress the intrusion of transmitted sound into the car interior.

Figure 8 is a schematic top view showing the configuration of the upper floor panel, with a portion cut away. Figure 9 is a cross-sectional view of the upper floor panel (cross-section G-G in Figure 8). The upper floor panel 72 is composed of a bone member 72b that forms an outer frame and has a roughly U-shaped cross-section, an iron-based face plate 72a that is friction stir welded to one edge 72b1 of the bone member 72b, a back plate 72c that is fastened to the other edge 72b2 of the bone member 72b by a mechanical fastening part 72d, and sound-absorbing material 72e that is provided in the area surrounded by the bone member 72b, the face plate 72a, and the back plate 72c.

<Production method>
For the upper floor panel 72, first, the face plate 72a cut into a predetermined shape is placed on a base plate, and then the rib member 72b is positioned so that the edge portion 72b1 of the rib member 72b abuts against the face plate 72a.

Then, the friction stir welding tool is brought into contact with the bone member 72b, rotated counterclockwise (around the left axis) when viewed from above, and advanced along the direction indicated by the tool advancement direction 30, thereby friction stir welding the bone member 72b and the face plate 72a together to form the weld line L1.

Next, a tool that rotates counterclockwise (around the left axis) when viewed from above is brought into contact with the bone member 72b and advanced in such a manner that the already joined weld line L1 is seen to the left of the tool's direction of travel, and the bone member 72b is friction-stir-welded to the face plate 72a to form the weld line L2. At this time, the center line of the weld line L2 is positioned outside the center line of the weld line L1, so that a part of the weld line L1 and a part of the weld line L2 overlap.

By friction stir welding the bone member 72b to the face plate 72a along the joining line L1 and the joining line L2 using the above-mentioned method, the hooking Fl formed at the joining line L1 and the hooking F2 formed at the joining line L2 overlap, so that when the joining line F1 and the joining line F2 are viewed macroscopically as a single joining line, joining portions with stable joining strength can be arranged at both ends (both sides of the joining line) in the width direction of the joining line.

Therefore, even if a force is applied in a direction that pulls the bone member 72b away from the face plate 72a, neither side of the joining line seen macroscopically is likely to become the starting point for separation, so the bone member 72b can be firmly connected to the face plate 72a.

If necessary, sound-absorbing material 72e is provided in the area surrounded by face plate 72a and bone member 72b, and then back plate 72c is positioned on the upper surface of edge 72b2 of bone member 72b, and back plate 72c is joined to bone member 72b with mechanical fasteners 72d such as rivets.

If the frame member 72b is made of a lightweight alloy such as aluminum, and the face plate 72a is made of a stainless steel plate (iron-based plate) that has high strength and corrosion resistance and weather resistance, the weight of the entire upper floor panel 72 can be reduced compared to when the entire panel is made of stainless steel plate. On the other hand, by placing a material with a large mass on the face plate 72a, a large transmission loss can be imparted to the upper floor panel 72, thereby reducing outside noise that penetrates the upper floor panel 72 and enters the vehicle interior.

Therefore, it is possible to provide a rail car structure that is highly reliable and lightweight, and yet has a structure with high transmission loss that can prevent transmitted sound from entering the car interior even if the bogie 2 and various electrical equipment, which are likely to be sound sources, are located below the upper floor panel 72.

In addition, instead of the above-mentioned upper floor panel 72, an upper floor may be constructed by stacking an iron-based floor plate as an iron-based face plate on an aluminum alloy cross beam (floor beam) 12 as an aluminum-based frame member, and then inserting a friction stir welding tool T from the side of the cross beam 12, in a similar joining form to the upper floor panel 72.

More specifically, the cross beam 12 is brought into close contact with the steel-based floor plate, and the tool T is rotated counterclockwise while moving along a first direction to form a first weld line L1 where the cross beam 12 is friction stir welded to the steel-based face plate. The tool T is further rotated counterclockwise while moving along a second direction opposite to the first direction, with the first weld line L1 facing to the left of the direction of travel of the tool T, to form a second weld line L2 where the cross beam 12 is friction stir welded to the steel-based face plate. At this time, a portion of the first weld line L1 and a portion of the second weld line L2 overlap in the width direction.

FIG. 10 is a flow chart showing the process of joining the side structure and the upper floor panel.
In step S10, the manufacturing process for joining the side structure 6 and the upper floor panel 72 is started. First, in step S20, the face plates 6a and 72a are placed on a surface plate. Next, in step S30, the frame members 6b and 72b are positioned on the face plates 6a and 72a.

After that, in step S40, the tool rotating around the left axis is brought into contact with the bone members 6b, 72b and advanced in the direction of the tool's advancement 30, friction stir welding the face plates 6a, 72a and the bone members 6b, 72b together to form a first joint line L1. Furthermore, in step S50, the tool rotating around the left axis is brought into contact with the bone members 6b, 72b and advanced in a manner that the joint line L1 is seen to the left of the advancement direction (31), friction stir welding the face plates 6a, 72a and the bone members 6b, 72b together to form a second joint line L2. In step S60, the joining process ends.

A rail vehicle having a side structure or top panel manufactured using a manufacturing method including the above steps is lightweight and has the characteristic of having a large transmission loss that can suppress the intrusion of transmitted sound into the vehicle interior.

The present invention is not limited to the above embodiment. For example, although the friction stirring tool is rotated counterclockwise in the above example, it may be rotated clockwise. In that case, however, when moving the tool along the second welding line, it is necessary to move the tool while looking at the first welding line to the right of the traveling direction.

1...Railway vehicle, 2...Bogie,
3... structure, 5... roof structure,
6... Side structure, 6a... Vehicle exterior plate,
6b... bone member (pillar), 6bh... edge portion,
9...Given structure, 12...Horizontal beam,
30, 31...Arrows indicating the direction of tool movement,
32...Arrow indicating the rotation direction of the tool,
69...Partition wall, 70...Seat,
72...upper floor panel, 72a...face plate,
72b... bone member; 72b1, 72b2... edge portion;
72c...back plate, 72d...mechanical fastening portion (rivet),
72e...sound absorbing material, 74...cabin partition wall,
76...Partition door, 90...Railway,
92...platform; L1, L2...joint line;
F1, F2...hooking defect, T...tool,
x: longitudinal direction (rail direction), y: width direction (sleeper direction),
z: Height direction

Claims (1)

A frame forming the floor surface;
Side structures erected at both ends in a width direction of the frame;
An upper floor panel that constitutes the underframe;
A method for manufacturing a railway vehicle structure having
The side structure includes:
a ferrous face plate formed from a ferrous material;
an aluminum-based frame member that is placed on the vehicle interior side of the iron-based panel and is made of an aluminum-based material;
It has
The aluminum-based frame member has a top hat-shaped cross section intersecting a longitudinal direction of the aluminum-based frame member and has a pair of edges,
The iron-based face plate and the edge portion are brought into close contact with each other,
When a friction stir welding tool is brought into contact with the aluminum-based frame member from the side of the portion of the aluminum-based frame member that is in close contact with the steel-based face plate and the aluminum-based frame member, and the tool is rotated around its axis while moving the tool so as to overlap the welding lines, the steel-based face plate and the aluminum-based frame member are friction-stir-welded to each other,
While rotating the tool around a counterclockwise axis, the tool is advanced along a first direction to form a first weld line by friction stir welding the edge portion to the ferrous face plate;
While rotating the tool counterclockwise, the tool is advanced along a second direction opposite to the first direction while viewing the first welding line to the left of the traveling direction of the tool, thereby forming a second welding line by friction stir welding the edge portion to the iron-based face plate;
a method for manufacturing a railway vehicle body structure, comprising overlapping a portion of the first weld line and a portion of the second weld line in a width direction of the aluminum-based frame member so that a hooking defect caused by friction stir welding to form the first weld line overlaps with a hooking defect caused by friction stir welding to form the second weld line.

Images