Wire harness

Details Wire harness Wire harness

2001-09-19

2004-05-18

Patel, Dhiru R (Department: 2831)

Electricity: conductors and insulators

Conduits, cables or conductors

C174S068300, C174S0720TR, C174S135000, C439S207000, C052S220700

Reexamination Certificate

active

06737585

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a wiring harness formed by combination of a plurality of sub-harnesses.
2. Description of the Related Art
A wiring harness for use in an automobile usually comprises a plurality of electric wires and connectors and has a complicatedly-branched geometry. Assembly of a wiring harness into a finished product through a single operation is not easy. Therefore, there is employed a series of manufacturing processes wherein a wiring harness is separated into a plurality of sub-harnesses of smaller blocks. After having been assembled individually, the sub-harnesses are connected into a completed wiring harness (see, for example, Japanese Patent Application Laid-Open No. 25781/1999).
The size of each block of sub-harness is determined in consideration of ease of assembly of sub-harnesses. For example, a wiring harness is separated into sub-harnesses such as those shown in FIG.
14
. Sub-harnesses
101
X and
101
Y are assembled, by means of inserting terminal hardware pieces
104
F connected to respective ends of electric wires
103
extending between a plurality of connectors
102
A,
102
B,
102
C,
102
D, and
102
E. As a result of the wiring harness having been separated in the manner as mentioned above, the electric wires
103
must be connected to other sub-harnesses (not shown) disposed between the two sub-harnesses
101
X and
101
Y. Therefore, after-insert terminals
104
R each having one end that is not connected to the connectors
102
A through
102
C are exposed outside the sub-harnesses
101
X and
101
Y so as to be inserted into other sub-harnesses in a subsequent bundling process.
As shown in
FIG. 15
, the sub-harness
101
X is laid along wire holders
106
situated upright on a work table
105
for assembling and bundling the sub-harnesses
101
X and
101
Y. In this state, the after-insert terminals
104
R to be inserted into the connectors
102
D and
102
E of the remaining sub-harness
101
Y remain exposed. Subsequently, as shown in
FIG. 16
, the remaining sub-harness
101
Y is laid along predetermined paths, and the after-insert terminals
104
R of the sub-harness
101
X are inserted into the corresponding connectors
102
D and
102
E, respectively. Similarly, the after-insert terminals
104
R of the sub-harness
101
′ are also inserted into the corresponding connectors
102
A and
102
B of the sub-harness
101
X. Thus, the wiring harness is assembled.
Terminal hardware which is connected to the terminals of the electric wires
103
and is to be inserted into the connectors
102
A through
102
E includes a insulation displacement terminal
104
a
and a crimp terminal
104
b
. As shown in
FIG. 17
, the insulation displacement terminal
104
a
is constituted by means of press-fitting the electric wire
103
into pressure-connecting blades
107
. As shown in
FIG. 18
, an insulating sheath
103
a
provided at the extremity of the electric wire
103
is stripped, thereby uncovering cores
103
b
. The thus-exposed cores
103
b
are crimped by means of a wire barrel
108
, thereby constituting the crimp terminal
104
b.
In connection with the crimp terminal
104
b
, the cores
103
b
are strongly crimped by the wire barrel
108
by means of a press. Hence, there is yielded an advantage of superior reliability of electrical contact with the electric wire
103
. Further, the crimp terminal
104
b
possesses high tensile strength and is less impervious to causing removal of the electric wire
103
. However, processing pertaining to complicated processes, such as stripping of the electric wire
103
and crimping of the electric wire using a press machine, must be performed for each of the crimp terminals
104
b
(for each electric wire
103
). Thus, the wiring harness becomes costly, thereby deteriorating manufacturing efficiency.
In connection with the insulation displacement terminal
104
a
, there is no necessity of stripping the electric wire
10
or press-fitting the electric wire
103
to the insulation displacement terminal
104
a
. The only requirement is to merely push the electric wire
103
into the pressure-connecting blades
107
. By means of a single operation, a plurality of electric wires
103
can be pressure-connected to a plurality of insulation displacement terminals
104
a
aligned in line. Further, a process of inserting the insulation displacement terminal
104
a
crimped to the electric wire
103
into the connectors
102
A through
102
E can be automated. Hence, there is yielded an advantage of ability to efficiently manufacture sub-harnesses at lower cost.
In order to curtail manufacturing costs or improve manufacturing efficiency, all terminal hardware pieces, including the terminals
104
F to be inserted into the connectors
102
A through
102
E and after-insertion terminals
104
R which remain exposed and are not inserted into the connectors
102
A through
102
E when the sub-harnesses
101
X and
101
Y are not combined, are desirably formed from the insulation displacement terminals
104
a.
However, in relation to the insulation displacement terminal
104
a
, the electric wire
103
is merely press-fitted into the pressure-connecting blades
107
. Hence, the electric wire
103
is readily removed from the insulation displacement terminal
104
a
. Further, press-fitting is inferior to crimping in terms of protection of a connection section (i.e., a pressure-connecting section) under external force. The after-insertion terminals
104
R are transported or handled while temporarily being in an exposed state. Against such a backdrop, crimp terminals
104
b
, rather than insulation displacement terminals
104
a
, are more preferably employed as the after-insertion terminals
104
R.
In relation to the electric wire
103
of the after-insertion terminal
104
R, there is a conceivable method of connecting the insulation displacement terminals
104
a
to ends of the electric wires
103
to be inserted into the connectors
102
A through
102
E and connecting the crimp terminals
104
b
to the remaining ends of the electric wires
103
as the after-insertion terminals
104
R. However, connecting two different connection types of terminal hardware pieces; that is, the insulation displacement terminal
104
a
involving press-fitting and the crimp terminal
104
b
involving crimping, to a single electric wire
103
results in considerable deterioration of manufacturing efficiency. Hence, such a method is desirably avoided.
Crimping is not applied solely to connection of the after-insertion terminal
104
R. For instance, terminal hardware (see
FIG. 19
) to be connected to an electric wire of special form, such as a shield wire
103
S having a shield layer
103
Sa, and terminal hardware (see
FIG. 20
) which is to be used in an exposed form and not connected to a connector even when a wiring harness is completed (see FIG.
20
), such as a ground terminal
104
E, must employ crimping as a connecting method.
As mentioned above, in terms of cost, use of the insulation displacement terminals
104
a
is preferable at the time of manufacture of the sub-harnesses
101
X and
101
Y and a wiring harness. In spite of this, there has been a necessity of employing crimp terminals
104
b
for a portion of terminal hardware pieces. Further, difficulty is encountered in mixedly employing the crimp terminal
104
b
and the insulation displacement terminal
104
a
for each of the sub-harnesses
101
X and
101
Y. Hence, the majority of related-art sub-harnesses
101
X and
101
Y use only the crimp terminals
104
b
. The insulation displacement terminals
104
a
are used in only special portions of a sub-harness where there is no necessity of using the crimp terminals
104
b.
SUMMARY OF THE INVENTION
The present invention has been conceived against the foregoing backdrop and an object of the invention is to provide a wiring harness which enables effective heavy use of sub-harnesses using insulation displacement terminals.
To this end, the present invention provides a wire harness form

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