Hitachi, Ltd.

Yoshihiko Ina

Masakuni Ezumi

Toshiaki Makino

Takeshi Kawasaki

Sumio Okuno

Kazusige Fukuyori

Tetsuya Matsunaga

Seijiro Todori

Takahisa Yamamoto

Takeshi Tanaka

Hideyuki Nakamura

Masaki Yono

Nobuaki Mizuguchi

Syu Nakaigawa

Shinya Mitsudomi

This invention relates to a system for mounting an underfloor electronic equipment to a rolling stock body having an underfloor storage portion formed under the floor in the longitudinal direction of the body as a portion of the body. The underfloor storage portion comprises a guidance tool for guiding and supporting the underfloor electronic equipment formed as a unit, a body-side connector corresponding to an electronic equipment-side connector formed to the electronic equipment, and a fixing tool for fixing the electronic equipment to the underfloor storage portion. The underfloor electronic equipment comprises a moving means guided by the guidance tool and the electronic equipment-side connector corresponding to the body-side connector. The electronic equipment can be moved by the guidance tool between a fixing position within the storage portion and a removal position outside the storage portion, the fixing tool used to fix the equipment to the fixing position where the equipment is electrically connected. The present invention facilitates maintenance and replacement of the electronic equipments and shortens operation time.

System for mounting an underfloor electronic equipment

A front end portionis disposed on the front end of a car body. The floor thereof consists of extruded hollow membersthat constitute a shock absorber. The shock absorberis divided into an upper shock absorberand a lower shock absorber. Annealed extruded hollow members are used to form the hollow member. The hollow membersare disposed so that their direction of extrusion corresponds to the longitudinal direction of the car body. The hollow membersare divided longitudinally into two portions by a plate. At the width-direction ends of member, the face platesandare welded onto plates. Upon receiving impact load, membersfold up into concertinas, absorbing the impact force. Since membersare separated by a plate, they deform evenly and continuously into concertinas instead of being bent in half, capable of absorbing a large energy.

Railway car

Abutted portions of face plates and of frame members and are friction stir welded. With the abutting, a projecting portion of an end portion of the face plate of the frame member is inserted into a recessed portion of an end portion of the face plate of the frame member . By this engagement, the outer face on one face side of the face plates and form a smooth surface, so that there is no step at the joined edges. Next, a rotary tool is inserted into the gap between the abutted plates, from the side of the raised portions and of the face plates and , while the other faces and of the face plates and are supported flatly on a bed during the friction stir welding. Accordingly, the welding of the engaged plates can be carried out without any step-wise difference.

Frame member for friction stir welding

A front end portion is disposed on the front end of a car body. The floor thereof consists of extruded hollow members that constitute a shock absorber . The shock absorber is divided into an upper shock absorber and a lower shock absorber . Annealed extruded hollow members are used to form the hollow member . The hollow members are disposed so that their direction of extrusion corresponds to the longitudinal direction of the car body. The hollow members are divided longitudinally into two portions by a plate . At the width-direction ends of member , the face plates and are welded onto plates . Upon receiving impact load, members fold up into concertinas, absorbing the impact force. Since members are separated by a plate, they deform evenly and continuously into concertinas instead of being bent in half, capable of absorbing a large energy.

End portions of face plates and of a hollow extruded frame member are connected with a rib and these end portions are welded to end portions of face plates and of a hollow extruded frame member using friction stir welding. A visible outline of a connection portion of the end portion of the face plate and the rib is constituted by circular arcs and which are recessed in the hollow extruded frame member . A visible outline of a connection portion of the end portion of the face plate and the rib is constituted by circular arcs and which are recessed in the hollow extruded frame member . The diameter of the circular arc ( ) is smaller than the diameter of the circular arc ( ). Accordingly, a structural body having a light weight structure can be obtained.

Structural body formed by friction stir welding of hollow extruded frame members

Abutted portion of face plates and of frame members and are friction stir welded. With the abutting, a projecting portion of an end portion of the face plate of the frame member is inserted into a recessed portion of an end portion of the face plate of the frame member . By this engagement, the outer faces on one face side of the face plates and form a smooth surface, so that at the joined edges there is no step. Next, a rotary tool is inserted into the gas between the abutted plates from the side of the raised portions and side of the face plates and , while the other faces and of the face plates and , are supported flatly on a bed during the friction stir welding. Accordingly, the welding of the engaged plates can be carried out without any step-wise difference.

Friction stir welding method

Car body

When an insertion force of a rotary tool,has searched, it is made clearly that the force at the insertion initial time is large and when a friction stir joining is an ordinary operation time, the force becomes small. According, it is preferable to make small the insertion force at the insertion initial time. To members,to be subjected to a joining at a position where the friction stir joining starts a hole,is opened, and this hole,after the rotary tool,has inserted, since a move of the rotary tool,is made to begin, a lowering of the insertion force can be attained.

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Kudamatsu, Japan

Yoshihiko Ina