Stock material or miscellaneous articles – All metal or with adjacent metals – Composite; i.e. – plural – adjacent – spatially distinct metal...
Reexamination Certificate
1998-04-17
2001-02-06
Zimmermann, John (Department: 1775)
Stock material or miscellaneous articles
All metal or with adjacent metals
Composite; i.e., plural, adjacent, spatially distinct metal...
C428S648000, C428S929000, C439S886000
Reexamination Certificate
active
06183885
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a fitting-type connection terminal used in electric wiring in an automobile, an industrial equipment and so on.
2. Related Art
Generally, in electric wiring used in an automobile, an industrial equipment and so on, tinning has heretofore been applied to a fitting-type connection terminal used for connecting wires together. The purpose of this is that when connecting the terminals together, an oxide film on the surface of the tin film is destroyed by friction, thereby causing fresh tin to adhere to the terminal, so that a low contact resistance can be stably obtained.
In electric wiring used in a particularly-important signal circuit, for example, for an ABS (anti-lock braking system) and an air bag, connection terminals have been plated with gold.
The above adhesion of the tin film is due to the low hardness of tin (Vickers hardness of 40 to 80). However, the low hardness of tin invites a problem that an increased insertion force is required when connecting the terminals together. Namely, during the fitting connection of the terminal, the tin film is worn by adhesion, and the terminal is fitted against the deformation resistance of tin, so that the insertion force is increased.
Incidentally, in electric wiring in an automobile and so on, it is a common practice to connect a bundle of wires (hereinafter referred to as “wire harness”) by the use of only one connector, and the force required for connecting the connector can be estimated by multiplying an insertion force, required for one terminal, by the number of wires (conventionally, 10 to 20 poles). Therefore, if the insertion force per terminal is high, the force required for the connection of the connector becomes a large value corresponding to the number of wires of the wire harness.
Particularly, recently, with the marked advance and development of car electronics, the number of electronic devices and CPUs, mounted on an automobile, has greatly increased, and therefore the number of wires of the wire harness has increased, and it has been eagerly desired to achieve a multi-pole design of a connector (e.g., 30 to 40 poles).
However, as described above, in the case of the multi-pole design of the connector, the force required for the connection of the connector increases in proportion to the number of the wires, and the connection of the connector can not be effected without the use of an auxiliary mechanism such as a bolt and a lever. Therefore, even if the terminal is formed into a small size, the auxiliary mechanism prevents the compact, lightweight design of the connector.
One proposal to reduce the insertion force for the terminal is to reduce a contact pressure (i.e., pressing force applied to a contact point at a fitting portion). In this case, however, a stable, low contact resistance can not be obtained. In other words, it is difficult to reduce the terminal insertion force while maintaining the stable contact resistance, and therefore the auxiliary mechanism becomes indispensable when forming the connector into a multi-pole design, and this prevents the compact, lightweight design of the connector.
When gold is plated on the connection terminals, the low contact resistance can be obtained even with the low contact pressure, and therefore the terminal insertion force can be reduced, and the force, required for the connection of the connector, is not much increased. However, the cost of the gold plating is several times to several tens of times higher than the cost of the tinning, and therefore this is not suitable particularly for the multi-pole connector.
SUMMARY OF THE INVENTION
With the above problems in view, it is an object of this invention to provide a fitting-type connection terminal in which an insertion force for a terminal can be reduced while maintaining a stable contact resistance.
In order to solve the above problems, according to the invention of a first aspect of the invention, there is provided a fitting-type connection terminal for achieving electrical contact by fitting a male member and a female member together;
wherein a tin film, having a thickness of 0.1 &mgr;m to 0.3 &mgr;m, is formed by plating on sliding-contact portions of a base material of one of the male and female members while a tin film, having a thickness of not less than 0.1 &mgr;m, is formed by plating on sliding-contact portions of a base material of the other member, the sliding-contact portions of the base material of the one member being in sliding contact with the sliding-contact portions of the base material of the other member during the fitting operation.
In the fitting-type connection terminal according to a second aspect of the invention, the tin film, having a thickness of 0.1 &mgr;m to 0.3 &mgr;m (preferably 0.1 &mgr;m) is formed on one of the male and female members whose sliding-contact portions are larger in area than the sliding-contact portions of the other member, while the tin film, having a thickness of 0.3 &mgr;m to 1.0 &mgr;m, is formed on the other member having the sliding-contact portions of a smaller area.
In the fitting-type connection terminal according to a third aspect of the invention, a diffusion barrier layer is interposed between the base material and the tin film in each of the male and female members.
In the fitting-type connection terminal according to a fourth aspect of the invention, the diffusion barrier layer is a nickel film formed by plating.
REFERENCES:
patent: 3718750 (1973-02-01), Sayers
patent: 4723923 (1988-02-01), Senor et al.
patent: 5028492 (1991-07-01), Guenin
patent: 5141702 (1992-08-01), Guenin et al.
patent: 5235743 (1993-08-01), Endo et al.
patent: 5272295 (1993-12-01), Sawada et al.
patent: 5322575 (1994-06-01), Endo et al.
patent: 5391097 (1995-02-01), Kerul
patent: 5634829 (1997-06-01), Kerul
patent: 5853557 (1998-12-01), Souza et al.
patent: 2-17637 (1990-04-01), None
patent: 5-258633 (1993-10-01), None
patent: 7-249445 (1995-09-01), None
patent: 8-7960 (1996-01-01), None
patent: 10-46363 (1998-02-01), None
patent: 10-265992 (1998-10-01), None
patent: WO 91/13754 (1991-09-01), None
patent: WO 97/22472 (1997-06-01), None
Fujii Atsuhiko
Isono Nobuaki
Kawaguchi Masahiro
Nakamura Atsushi
Shintani Yasuhiro
Harness System Technologies Research Ltd.
Oliff & Berridg,e PLC
Zimmermann John
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