Hitachi, Ltd.

Toshiaki Sagawa

Takeshi Kawasaki

Hideyuki Nakamura

Masakuni Ezumi

Toshiaki Makino

Masaki Yono

Sumio Okuno

Kenzi Toudo

Motoshi Miyanaka

Upon forming a railway car composed of plural hollow shape members , annealed hollow shape members are used to form the ends of an underframe . The hollow shape members are disposed so that their longitudinal orientation equals the longitudinal direction of the car body. The underframe is formed by disposing plural hollow shape members adjacent one another in the width direction and welding them together by friction stir welding. When the hollow shape members receive impact load, the ends of the members deform into concertinas, thereby absorbing the impact force. At this time, the friction stir welded portions also receive the impact force, but cracks are not created at the friction-stir-weld joints, and the weld joints do not prevent the hollow shape members from deforming into concertinas.

Railway car

An abutted portion of face plates ( and ) of hollow frame members ( and ) is carried out according to a friction stir joining. Next, a connection member ( ) is mounted, one end of the connection member ( ) is abutted to an end portion of the face plate ( ) of the hollow frame member ( ). Under this condition, the abutted portion between the face plate ( ) and the connection member ( ) is carried out according to the friction stir joining. An overlapping portion between another end of the connection member ( ) and the hollow frame member ( ) is carried out according to the friction stir joining. According to demands, the connection member ( ) and the face plate ( ) of the hollow member ( ) are welded. Without of regard of a dimension accuracy of the hollow frame member and the like, a good joining from one side face of the hollow frame member can be carried out.

Connection member for friction stir welding

A hollow frame member is constituted by two face plates 11, 12 (21, 22) joined in a truss shape by ribs. End portions of one of the face plates are positioned in the vicinity of an apex of the truss structure of the hollow frame member. End portions of the other of the face plates have a projection extending toward the end portions of the face plates. The face plates are joined by friction stir welding. Due to the presence of the ribs, the load during the friction stir welding time is easily supported.

Structural body and method of manufacture thereof

An abutted portion of face plates and of hollow frame members and is carried out according to a friction stir joining. Next, a connection member is mounted, one end of the connection member is abutted to an end portion of the face plate of the hollow frame member . Under this condition, the abutted portion between the face plate and the connection member is carried out according to the friction stir joining. An overlapping portion between another end of the connection member and the hollow frame member is carried out according to the friction stir joining. According to demands, the connection member and the face plate of the hollow member is welded. Without of regard of a dimension accuracy of the hollow frame member and the like, a good joining from one side face of the hollow frame member can be carried out.

Structure body for use in friction stir welding

A hollow frame member is constituted by joining with a truss shape by ribs A, B ( A, B) between two face plates ( ). An end portion of one of the hollow frame member is connected according to the rib A for constituting the truss. A face plate of another hollow frame member is joined at a vicinity of an apex of the truss of the hollow frame member . A face plate of the hollow frame member is joined at a vicinity of an apex of the truss of the another hollow frame member . A load during a friction stir joining is received according to the ribs A, B ( A, B). Since the truss structure is formed totally, the light weight structure and the high rigidity performance can be obtained.

Structure body and a manufacturing method of a structure body

The object of the present invention is to weld a hollow-shaped material from one side, regardless of the size accuracy of the hollow-shaped material or the like, and to form the joint with higher strength. Projecting segments of face plates of hollow-shaped materials are friction stir welded from above. Next, a connecting material is placed on the upper face plates of the hollow-shaped materials , and is friction stir welded from above. The welding region exists at the node between a rib connecting the two face plates ( ) and the face plate ( ). The joint of the connecting material and the face plates are lap joint. Not butt joint. Therefore, the hollow-shaped materials could be welded with ease, even though there exists manufacturing tolerance, or tolerance in arrangement of the hollow-shaped materials

Method of friction stir welding structural body, structural body, and extruded material

A hollow frame member is constituted by two face plates ( ) joined in a truss shape by ribs A, B ( A, B). End portions of one of the face plates and are positioned in the vicinity of an apex of the truss structure of the hollow frame member. End portions of the other of the face plates and have a projection extending toward the end portions of the face plates and . The face plates and are joined by friction stir welding from an upper portion. Next, a connection member is arranged between the ends of the face plates and , and from an upper portion the friction stir welding is again carried out. Due to the presence of the ribs A, B ( A, B), the load during the friction stir welding time is easily supported. Since the truss structure is formed totally, a light weight structure with a high rigidity performance can be obtained.

Structure body and method of manufacture thereof

End portions of extruded frame members,and,have increased thickness portions,and,which project toward an outer side thereof. A rotary body,is inserted into the increased thickness portions,and,and is rotated so as to carry out friction stir welding of the frame members. A large diameter portion,of the rotary body,is inserted to a position between the apex of the increased thickness portion and an extension line of an outer face of the plates,and,of the extruded frame members,and,as the rotary body,is rotated. Further, the rotary body,is reciprocated in a direction orthogonal to the welding line as it is moved along the welding line. Accordingly, friction stir welding can be carried out fully. In the friction stir welding, due to a rotation of the rotary body,, even when a gap g between two extruded frame members to be subjected to welding is large, it is possible to carry out the friction stir welding.

Friction stir welding method and friction stir welding apparatus

An abutted portion of face plates,and,of hollow frame members,and,is carried out according to a friction stir joining. Next, a connection member,is mounted, one end of the connection member,is abutted to an end portion of the face plate,of the hollow frame member,. Under this condition, the abutted portion between the face plate,and the connection member,is carried out according to the friction stir joining. An overlapping portion between another end of the connection member,and the hollow frame member,is carried out according to the friction stir joining. According to demands, the connection member,and the face plate,of the hollow member,is welded. Without of regard of a dimension accuracy of the hollow frame member and the like, a good joining from one side face of the hollow frame member can be carried out.

Friction stir joining method

A flame detecting apparatus used in a combustion control apparatus for a water heater provided with a gas burner comprises a pressure switch serving as means for detecting presence or absence of flame and a voltage comparison circuit serving as means for determining the presence or absence of the flame on the basis of the input signal supplied by the pressure switch. The voltage comparison circuit has an offset voltage and has a non-inverting input terminal connected only to the ground. A first circuit including a first resistor and a diode connected in series to each other is connected in a loop together with the pressure switch, an impedance network and an AC voltage source so that an AC current which flows when the pressure switch is closed is rectified by the first circuit and a negative voltage obtained through the use of a capacitor or the like is applied to the inverting input terminal of the voltage comparison circuit to thereby detect the flame, while preventing erroneous operation of the voltage comparison circuit due to a short-circuit possibly produced across the resistor. By connecting a second resistor in parallel with at least the diode of the first circuit, erroneous detection of the flame ascribable to contact failure of the pressure switch as well as leakage is prevented. The capacitor may be replaced by a resistor to reduce expenditure.

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Yanai, Japan

Toshiaki Sagawa