Metal fusion bonding – Process – Using dynamic frictional energy
Reexamination Certificate
2000-05-04
2001-11-06
Dunn, Tom (Department: 1725)
Metal fusion bonding
Process
Using dynamic frictional energy
C156S073500, C228S119000
Reexamination Certificate
active
06311889
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing a structural body and an apparatus therefor; and, more particularly, the invention relates to a friction stir method of welding elements of a structural body and a friction stir welding apparatus therefor.
Two members to be subjected to friction stir welding have a raised portion at one side thereof where they are abutted, and, from a side of the raised portion, a rotary tool is inserted into a joint between the members and then a friction stir welding is carried out. In friction stir welding, when a gap exists between two members to be subjected to the friction stir welding process, a reduced thickness of the two members by the material contributed by the raised portion is compensated.
After the friction stir welding, the remainder of the raised portion of the two members that is no longer needed is cut off and removed in such a way that the outer face of the member formed by friction stir welding is flat and smooth. This technique is disclosed in Japanese application patent laid-open publication No. Hei 09-309164 (EP 0797043 A2).
Further, a cutter may be provided which operates in a radial direction of the rotary tool. The small diameter portion of the rotary tool is inserted into the joint between the members and a boundary formed between the large diameter portion and the small diameter portion of the rotary tool is brought into contact with the members to be subjected to the friction stir welding. The cutter projects toward a side of the large diameter portion of the rotary tool from the boundary. This cutter can cut off or delete a burr which is generated as a result of the friction stir welding. This technique is disclosed in Japanese application patent laid-open publication No. Hei 10-71477 (U.S. Pat. No. 5,794,835, EP 0810055 A1).
Further, the rotary tool and the cutter may be provided separately, and, as the cutter, an end milling member may be used. This technique is disclosed in Japanese application patent laid-open publication No. Hei 10-175089.
When the members having a raised portion along one side thereof are subjected to friction stir welding, a burr is typically generated at the welding joint. Further, at least a part of the raised portion of the member subjected to the friction stir welding is left. In a case where the raised portion is formed on the outer face of a structural body, it is necessary to remove the residual raised portion. Thus, to the rotary tool, a cutter is attached to cut off any excessive raised portion and the burr on the weld joint as the welding occurs. However, such cutting tends to produce chips, the existence of which makes it difficult to carry out a good friction stir welding.
The above-stated considerations will be explained in more detail. To a front portion in an advancing direction of the rotary tool, an optical sensor is provided for detecting optically the raised portion of the member being subjected to the friction stir welding. This optical sensor can detect the width of the two abutting raised portions of the members, and thereby guide the rotary tool to a position at the center thereof where the welding joint is located. Further, the optical sensor can detect the height of the raised portion of the members, and, subject to that determination, the amount the rotary tool should be inserted into the joint of the members to be welded can be determined suitably. However, the detection range of the optical sensor is affected when chips enter the working area, making it impossible to carry out a precise detection.
Further, at a front portion and at a rear portion of the rotary tool, rollers are installed, which rollers ride on the surface of the raised portion of the members being subjected to friction stir welding or the vicinity of the raised portion relative to a bed. Since chips collect at the rear portion of the rotary tool, the chips tend to obstruct movement of the rear roller. For this reason, the member being subjected to the friction stir welding is likely to be damaged due to the presence of these chips.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a method of manufacture of a structural body and a manufacturing apparatus therefor, as well as to a friction stir welding method for forming a structural body and a friction stir welding apparatus wherein a good structural body can be obtained.
Another object of the present invention is to provide a method of manufacture of a structural body and a manufacturing apparatus therefor, using a friction stir welding method, wherein a structural body having a small raised portion can be obtained.
The above stated objects can be attained be provision of a cutting means and a sensing means in an arrangement in which air is caused to flow out from a front portion in a moving direction toward a rear portion or in a lateral direction relative to the moving direction to clear away any chips.
The above stated objects can be attained by using a cutter which has a rotation radius larger than the width of the raised portion of the structural body.
The above-stated objects can be attained by way of a manufacturing method including the steps of relatively moving a cutting means along a welding joint while guiding said cutting means in response to a sensing means for detecting the location of said welding joint, cutting excess material from said welding joint, and directing an air flow from a front portion in said moving direction to a rear portion or from a lateral direction toward said moving direction across the welding, portion to clear away chips and other foreign matter.
The above stated objects can be attained by a manufacturing, method including the steps of guiding a cutting means in response to a sensing means for detecting, the location of a welding joint and cutting off an excess portion of said welding joint, directing an air flow toward a rear portion of said sensing means from a side of a front portion in an advancing direction of said sensing means toward the rear portion of said sensing means.
The above stated objects can be attained by a friction stir welding apparatus which comprises a bed for fixing members to be subjected to a welding, a head for carrying out a friction stir welding said members by moving along a joint between said members over said bed, said head comprising a rotary tool for effecting friction stir welding, cutting means for removing burrs, a sensing means provided at a front portion in an advancing direction of said rotary tool for detecting a center position where a welding joint is located, a cover for covering a housing of said sensing means, and an air nozzle for injecting an air jet against said cover.
REFERENCES:
patent: 4083323 (1978-04-01), Rote
patent: 4988201 (1991-01-01), Sugitani et al.
patent: 5794835 (1998-08-01), Colligan et al.
patent: 6050474 (2000-04-01), Aota et al.
patent: 6068178 (2000-05-01), Michisaka
patent: 9-309165 (1997-12-01), None
patent: 10-175089 (1998-06-01), None
Ezumi Masakuni
Fukuyori Kazusige
Satou Akihiro
Antonelli Terry Stout & Kraus LLP
Dunn Tom
Hitachi , Ltd.
Johnson Jonathan
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