Patent Grant
6838620
1. Field of the Invention
The present invention relates to a structure of mounting a terminal to a covered electric wire and a method thereof.
2. Description of the Related Art
A conventional method of mounting a terminal to a covered electric wire comprises a step of inserting a covered electric wire in which a covering at a front end is peeled and an electric conductor is exposed, to a terminal provided with a pair of hooks and a pair of crimp pieces, a step of crimping a blade with the electric conductor so as to conduct them, and a step of bending the crimp pieces in such a manner as to wrap the covering. As another method of mounting a terminal, there has been known a technique disclosed in Japanese Patent Application Laid-Open No. 2000-21543. In this technique, the terminal is constituted by a receiving portion for receiving a terminal end of an electric wire and a connecting portion for the other connecting terminal, and the method comprises a step of inserting a covered electric wire in which a covering at a front end is peeled, and a step of pressurizing and caulking the receiving portion from six directions with using a pair of dies. In this method, the receiving portion for receiving the electric conductor deforms in a shape having a cross section similar to a hexagon.
Since the electric conductor of the covered electric wire exposes near a connecting portion to the terminal according to both of the methods, there is a problem that the electric conductor and the terminal are exposed to an air or a water, thereby being easily oxidized. Further, in the technique disclosed in Japanese Patent Application Laid-Open No. 2000-21543 mentioned above, since the deformation is not generated in an axially symmetrical manner, it is easy that a gap is generated between the terminal and the electric conductor, and the air and the water easily enter between the electric conductor and the terminal. If a contact surface between the electric conductor and the terminal is oxidized, there is a problem that a conductivity is significantly reduced.
An object of the present invention is to provide a structure of mounting a terminal to a covered electric wire which is excellent in a sealing performance of an electric conductor and a contact surface of the terminal with the electric conductor, and can obtain a stable conductivity, and a method thereof.
According to the present invention, one end of a terminal is formed in a tube shape, and a terminal end of a covered electric wire in which a part of a covering is peeled is inserted to the one end of the terminal, and is uniformly caulked from a periphery. A length of the peeled covering is shorter than a depth of the tube-like portion of the terminal. Accordingly, a part of the covering is received in the tube-like portion and caulked so as to serve as an operation of a packing, thereby preventing water and an air from entering into an inner portion of the tube-like portion. Further, since the tube-like portion is uniformly caulked so as to be closely contact with the electric conductor, it is possible to obtain a comparatively large contact area, and it is possible to obtain a stable conduction.
According to a second aspect of the present invention, there is provided a mounting structure as recited above, wherein the tube-like portion is formed in a cylindrical shape, and the tube-like portion of the terminal to which the terminal end of the covered electric wire is inserted is drawn in an axial direction while being caulked. Since the tube-like portion has the cylindrical shape, it is possible to uniformly pressurize all around an outer periphery, and it is possible to plastically deform the terminal and the electric conductor In an axially symmetrical manner. Accordingly, it is possible to obtain a higher sealing performance and a more stable conduction than the case mentioned above.
According to a third aspect of the present invention, there is provided a mounting structure as recited above, wherein a plurality of projections for engaging with the covering of the covered electric wire and the electric conductor are provided on an inner surface of the tube-like portion in the terminal. In the structure mentioned above, the area in which the inner surface of the tube-like portion of the terminal and the electric conductor are in contact with each other is further increased, so that a smaller contact resistance and a stable conduction can be obtained.
In the structure of mounting the terminal according to the present invention, it is possible to more uniformly compress by using a swaging machine for compressing the tube-like portion. According to this method, it is possible to produce the terminal mounting structure provided with a further higher waterproof property.
A description will be given of a first embodiment according to the present invention with reference to
In a terminal mounting structure according to the first embodiment, a connecting terminal 11 shown in
A portion near the opening portion on the inner side surface of the wire end receiving portion 12 is formed as a guiding taper surface 16 as shown in FIG. 2. The guiding taper surface 16 makes an operation of inserting a covered electric wire 15 into the wire end receiving portion 12 easy.
In a terminal end of the covered electric wire 15, as shown in
Next, the wire end receiving portion 12 and the covered electric wire 15 are caulked by a swaging machine as shown in
A diameter of the wire end receiving portion 12 is uniformly compressed and is simultaneously extended in the axial direction, thereby being crimped with the covered electric wire 15. As a result, a length of the wire end receiving portion 12 becomes L2, which is longer than an initial length L1. The electric conductor 18 is compressed in the radial direction, and becomes in a state of being bit into each other while being plastically deformed. Further, as shown in
Another connecting terminal (not shown) is connected to the connecting portion 13. In the drawings, the connecting portion 13 is structured such as to be engaged with another connecting terminal, however, may be constituted by a male type or a female type connecting portion which is simply fitted and connected.
A description will be given of a relation between the wire end receiving portion 12 and the covered electric wire 15 and a relation between the electric conductors 18 with reference to
In the terminal end of the covered electric wire 15, as shown in
The electric conductor 18 is constituted by a bundle of conductive wires, however, since the conductive wires are crimped so as to be bit into each other as shown in
Further, as shown in
In the terminal mounting structure according to the present embodiment having the structure mentioned above, since it is possible to prevent the covered electric wire 15 provided with a waterproof function and the inner surface of the wire end receiving portion 12 from being oxidized and deteriorated, it is possible to realize the terminal mounting structure in which the electric resistance is low and stable.
Next, a description will be given of a second embodiment according to the present invention with reference to FIG. 9. The same reference numerals are attached to the same elements as those of the first embodiment, and a detailed description thereof will be omitted.
In the terminal mounting structure according to the second embodiment of the present invention, a connecting terminal 27 shown in
A plurality of projections 31 are provided on an inner surface of the wire end receiving portion 29. A plurality of projections 31 are formed in an annular shape, are respectively formed along a circumferential direction of the inner surface of the wire end receiving portion 29 and are arranged in a longitudinal direction of the wire end receiving portion 29 at a uniform interval. These projections 31 are structured such that a thickness thereof is gradually reduced from a base portion toward a front end and the front end forms an edge 35. The edge 35 makes an engagement of the covering 17 and the electric conductor 18 executed by a plurality of projections 31 mentioned below easy.
The shape of the projection 31 can employ various structures in addition to the shape mentioned above. A plurality of projections 31 are respectively formed in an annular shape in the structure mentioned above, however, the structure may be made such that a plurality of projections are annularly arranged along a circumferential direction. A cross sectional shape of the projection 31 may employ a rectangular shape. Further, in the above structure, a plurality of projections 31 are arranged at a uniform interval, however, one or a plurality of spiral projections may be employed.
An inner side surface near the opening portion of the wire end receiving portion 29 forms a guiding taper surface 16 as shown in FIG. 9. The guiding taper surface 16 makes an operation of inserting the covered electric wire 15 within the wire end receiving portion 29 easy.
In a terminal end of the covered electric wire 15, as shown in
Next, the wire end receiving portion 29 and the covered electric wire 15 are caulked by a swaging machine so that a whole circumference becomes uniform. A diameter of the wire end receiving portion 29 is uniformly compressed and is simultaneously extended in the axial direction, thereby being crimped with the covered electric wire 15. As a result, a length of the wire end receiving portion 29 becomes L2, which is longer than an initial length L1. The electric conductor 18 is compressed in the radial direction, and becomes in a state of being bit into each other while being plastically deformed. The projections 31 become in a state of being bit into the electric conductor 18, and a contact area between the electric conductor 18 and the wire end receiving portion 29 is increased. The projections 31 become in a state of being bit into the covering 17 received within the wire end receiving portion 29, whereby a closely contact performance is increased. Further, since an open end of the wire end receiving portion 29 is extended in the axial direction, the open end bites into the covering 17 in the axial direction.
In the structure of mounting the terminal to the covered electric wire 15 in which the connecting terminal 27 is used, the electric conductor 18 ate the terminal end of the covered electric wire 15 in which the predetermined length is peeled from the front end of the covering 17, and the covering 17 are engaged with a plurality of projections 31 so as to be crimped with the inner surface of the wire end receiving portion 29. Accordingly, in comparison with the case of the first embodiment, the contact area between the covered electric wire 15 and the connecting terminal 11 becomes further greater around the length of the wire end receiving portion 29, and the contact resistance becomes further smaller. Further, it is possible to effectively prevent the covered electric wire 15 from coming off and it is possible to secure a stable conduction. Further, since a gap between the covered electric wire 15 and the wire end receiving portion 29 becomes even smaller, it is possible to prevent the air and the water from entering between the both, and it is possible to restrict the oxidization of the contact surface.
The electric conductor 18 is constituted by a bundle of conductive wires, however, since the conductive wires are crimped so as to be bit into each other, the contact area between the respective conductive wires is increased, whereby it is possible to restrict the contact resistance to be low and the gap between the conductive wires is reduced. Accordingly, it is possible to prevent the air and the water from entering between the conductive wires, and it is possible to restrict the oxidization of the electric conductor 18.
Further, as shown in
In the terminal mounting structure according to the present embodiment having the structure mentioned above, since it is possible to prevent the covered electric wire 15 provided with a waterproof function and the inner surface of the wire end receiving portion 12 from being oxidized and deteriorated, it is possible to realize the terminal mounting structure in which the electric resistance is low and stable.
Although the invention has been described above by reference to certain embodiments of the invention, the invention is not limited to the embodiments described above. Modifications and variations of the embodiments described above will occur to those skilled in the art, in light of the above teachings.
| Number | Date | Country | Kind |
|---|---|---|---|
| P2000-313572 | Oct 2000 | JP | national |
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|---|---|---|
| 2000-021543 | Jan 2000 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20020050385 A1 | May 2002 | US |
