Metal fusion bonding – Process – Using dynamic frictional energy
Reexamination Certificate
2001-02-13
2003-07-01
Dunn, Tom (Department: 1725)
Metal fusion bonding
Process
Using dynamic frictional energy
C228S002100, C156S073500, C156S580000
Reexamination Certificate
active
06585147
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a friction agitation joining method for joining metallic members such as aluminum or its alloy members butted against each other. More particularly, the present invention relates to a friction agitation joining method for use in manufacturing, for example, tailored blank members, suspension arm members or engine mount members for automobiles, body panels for railroad vehicles and/or vessels, and electric mechanical members.
2. Description of Related Art
A friction agitation joining method belongs to a category of a solid-phase joining method. The friction agitation joining method has such advantages that it can be applied to various metal joining members regardless of the materials and that joining members are hardly deformed by thermal strains at the time of joining. Thus, in recent years, the method has been used for joining various structural members.
FIG. 5A
shows two pieces of plate-like metal joining members butted against each other to be joined by a friction agitation joining method.
In
FIG. 5A
, the reference numeral “
51
” denotes a thicker plate-shaped metal first joining member and “
52
” a thinner plate-shaped metal second joining member. These joining members
51
and
52
are arranged such that the lateral side surfaces thereof are butted against each other with the lower surfaces thereof flush with each other. Thus, a level difference corresponding to the thickness difference thereof is formed at the upper surface sides thereof. The reference numeral “
55
” denotes a butted portion of the joining members
51
and
52
. The reference numeral “
54
” denotes a stepped portion formed at the butted portion
55
on the upper surface sides of the joining members
51
and
52
.
In
FIG. 5B
, the reference letter “A′” denotes a joining device for performing a but-joining. This joining device A′ is comprised of a joining bed
80
(see FIG.
5
A), a joining tool
60
for performing a friction agitation joining and an elevator
70
.
The joining bed
80
is arranged such that the upper surface
81
thereof is disposed horizontally. On this upper surface
81
, both the aforementioned joining members
51
and
52
are placed with their upper surfaces thereof facing up. In these joining members
51
and
52
, the first joining member
51
corresponds to a joining member having a higher upper surface level as seen from its surface side, and the second joining member
52
corresponds to a joining member having a lower surface level as seen from its surface side.
The elevator
70
is arranged above the joining members
51
and
52
and capable of ascending and descending vertically.
The joining tool
60
having a rotation axis Q′ is provided with a pillar-like rotor
61
having a larger diameter and formed about the rotation axis Q′ and a pin-like probe
62
having a smaller diameter and integrally protruded from the rotation central portion of the end surface
61
a
of the rotor
61
along with the rotation axis Q′. This joining tool
60
is equipped to a rotation driving apparatus (not shown) for rotating the rotor
61
and the probe
62
about the rotation axis Q′. In the joining tool
60
, the peripheral edge of the end surface
61
a
of the rotor
61
is placed within the plane perpendicular to the rotation axis Q′. As shown in
FIG. 5B
, the end surface
61
a
of the rotor
61
is formed to have a flat surface perpendicular to the rotation axis Q′.
By the way, in cases where both the butted joining-members
51
and
52
are joined in a state that the stepped portion
54
is formed on the upper surfaces thereof, stress concentration will generate in the stepped portion
54
of the obtained joined portion, resulting in deteriorated strength reliability. Moreover, during the joining process, some materials of the joining members
51
and
52
softened by the frictional heat disperses from near the probe
62
, resulting in joint defects due to insufficient materials.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a friction agitation joining method which is favorably used for joining two plate-shaped joining members butted against each other such that a level difference is formed at upper surface sides thereof.
It is another object of the present invention to provide a friction agitation joining method which can enhance the joining operation efficiency of the aforementioned butted joining members.
Another objects of the present invention will be apparent from the following embodiments of the present invention.
In order to attain the aforementioned objects, according to the present invention, a friction agitation joining method for joining two plate-shaped joining members butted against each other with a level difference formed at upper surface sides thereof by utilizing a joining tool having a probe rotatable about a rotation axis thereof, comprising the steps of:
arranging the butted joining members so as to be inclined to a horizontal plane with one of the joining members having a higher upper surface level positioned at a lower side and the other of the joining members having a lower upper surface level positioned at a higher side;
inserting the probe rotating about the rotation axis into a butted portion of the butted joining members or the vicinity thereof in a state that the rotation axis is parallel to a vertical plane extending along the butted portion; and
moving the probe relative to the joining members along the butted portion with the probe inserted into the butted portion or the vicinity thereof.
According to the aforementioned friction agitation joining method, by downwardly moving the joining tool in the vertical direction, the probe can be quickly inserted into the butted portion of the joining members or its vicinity. This increases the insertion speed of the probe, resulting in enhanced joining operation efficiency.
It is preferable that the step of inserting the probe is performed in a state that the rotation axis is disposed vertically. In this case, the probe can be inserted more quickly. This further increases the probe insertion speed, resulting in further enhanced joining operation efficiency. Furthermore, as compared to the case where the joining tool is inclined so that the probe can be inserted into the butted portion of the joining members in an inclined state, it becomes possible to prevent the inclination of the joining tool due to the influence of gravity because the rotation axis of the probe is disposed vertically. Accordingly, a joined member with an excellent joined portion can be obtained.
Furthermore, it is preferable that the joining tool is attached to an elevator disposed above the butted joining members and capable of ascending and descending vertically and that the step of inserting the probe is performed by descending the elevator. In this case, the insertion of the probe can be performed with high efficiency by utilizing the elevator without attaching any additional device for inserting the probe.
Furthermore, it is preferable that the joining tool is provided with a rotor having a diameter larger than a diameter of the probe protruded from a part of an end surface of the rotor, the rotor being capable of rotating about the rotation axis, and that the step of moving the probe relative to the joining members is performed in a condition that the end surface of the rotor rotating about the rotation axis presses a shoulder portion of one of the joining members having a higher upper surface level formed at the butted portion. In this case, since the end surface of the rotor presses the shoulder portion of one of the joining members having a higher upper surface level formed at the butted portion, the shoulder portion will be plastically deformed into an inclined surface due to the pressing force. Consequently, stress concentration, which may be generated at the stepped portion, can be reduced.
Furthermore, it is preferable that the end surface of the rotor vertically presses
Edmondson L.
Showa Aluminum Corporation
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