JP3819229B2 - Connection structure between electronic unit and shielded cable - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to shielded cables covered by a plurality of wires collectively by braiding a common shield, the structure for connection to an electronic unit mounted on a vehicle.
[0002]
[Prior art]
When a cable is electrically connected to an electronic unit (for example, a control box of an electric motor) mounted on a vehicle, when it is necessary to shield between the electric wire and another circuit, a shielded cable is used as the cable. Is used. As this shielded cable, a cable in which each electric wire is covered with a flexible shield braid (for example, copper braid) is often used. An example of a conventional method for connecting such a shielded cable to the electronic unit will be described below with reference to FIGS.
[0003]
1) As shown in FIG. 7 , the terminal of each braid | blade 10 is removed by length L, and the terminal of each electric wire 12 is exposed.
[0004]
2) As shown in FIG. 8 , the end of each electric wire 12 is peeled off to expose the internal conductor 13, and a cylindrical waterproof plug 14 made of rubber or the like is fitted from the outside at a position immediately behind it. The waterproof plug 14 integrally includes a small-diameter crimp portion 14a, a large-diameter main body portion 14b, and a larger-diameter collar portion 14c in this order from the distal end side.
[0005]
3) The terminal fitting 16 is fixed to the end of each electric wire 12. As shown in FIG. 8 , the terminal fitting 16 includes a ring-shaped tip having a through-hole 16a, a conductor barrel 16b formed at the rear thereof, and an insulation barrel 16c formed at the rear thereof. The conductor barrel portion 16b is crimped around the inner conductor 13, and the insulation barrel portion 16c is crimped around the crimp portion 14a of the waterproof plug 14. As shown in FIG. 7 , a ring-shaped terminal fitting 16 'is also connected and fixed to the end of the drain wire 15 connected to the shield braid 10.
[0006]
4) As shown in FIG. 7 , the end of each electric wire 12 (that is, the terminal fitting 16) is inserted into a cylindrical insertion portion 19 provided in the unit housing 18 of the electronic unit, and each waterproof plug 14 is inserted into each of the insertion plugs. A waterproof structure is formed by press-fitting into the portion 19.
[0007]
5) The terminal fitting 16 of each electric wire 12 that has entered the unit housing 18 through the insertion part 19 is connected to an electronic circuit (not shown) housed in the unit housing 18.
[0008]
6) A screw 22 is inserted into a terminal fitting 16 'fixed to the end of the drain wire 15 and screwed into a screw hole 20 provided on the outer surface of the unit housing 18, whereby the terminal fitting 16' is fitted to the outer surface of the unit housing 18. Touch and fix. As a result, the shield braid 10 can be grounded through the drain wire 15, the terminal fitting 16 ′, and the outer surface of the unit housing 18.
[0009]
[Problems to be solved by the invention]
In the structure and method, when the terminal fitting 16 is fixed to the end of each electric wire 12, the end of the shield braid 10 must be removed by a length L in order to expose the electric wire end. Accordingly, in the region of this length L, each electric wire 12 is not covered with the shield braid 10 and is exposed to the outside, and the shielding performance is accordingly reduced. Further, in order to ground the shield braid 10, a grounding terminal fitting 16 ′ is fixed to the end of the drain wire 15 separately from the terminal fittings 16, and the terminal fitting 16 ′ is attached to the outer surface of the unit housing 18. It is necessary to perform the fixing work on the cover, which is troublesome and the connection structure is complicated.
[0010]
In view of such circumstances, an object of the present invention is to provide a structure capable of ensuring high shielding performance with a simple configuration at a connection portion between a shielded cable and an electronic unit.
[0011]
[Means for Solving the Problems]
As means for solving the above-mentioned problems, the present invention connects a wire of a shielded cable provided with a common shield braid that collectively covers these wires on the outside of a plurality of wires to a circuit of an electronic unit. A terminal fitting fixed to a terminal of each electric wire and connected to a circuit in the electronic unit, at least an outer surface is made of metal, and stores the circuit of the electronic unit, and A unit housing having an insertion portion for inserting the end of each electric wire, and a metal shield case fixed to the end of the shield braid so as to be conductive with the shield braid. The case includes a main body that covers the end of each electric wire inserted through each insertion portion in an area from the end of the shield braid to the unit housing, and the unit. And a portion secured to the outer surface of Tsu bets housing, by which this part is fixed to the unit housing outer surface, which together with the unit housing the shield case and braided for the shield to form a possible ground state And a wire holder that is housed in the shield case and fixes the relative position of the wires in the shield case to a position corresponding to the relative position of the insertion portions in the unit housing, A waterproof plug is provided between the outer peripheral surface of the electric wire and the inner peripheral surface of the insertion portion to prevent water from entering the electronic unit. The waterproof plug is fixed to the electric wire side by this clamping .
[0012]
According to this configuration, since the connection part of each electric wire and the unit housing is covered with the shield case, a series of shield structures from the shield braid to the unit housing are continuously formed to ensure high shielding performance. Can do. Further, since the shield case can be brought into a groundable state simply by fixing the shield case to the outer surface of the unit housing, the operation is also easy.
[0013]
Moreover, the housed in the shield case is provided with the wire holder for fixing the position corresponding to the relative positions of the electric wires to the relative positions of the insertion portions in the unit housing within the shield case, by the wire holder By fixing the relative positions of the electric wires, the operation of inserting each electric wire into each insertion portion of the unit housing becomes easier.
[0014]
Furthermore, each of the electric wires has a structure in which a waterproof plug is provided between the outer peripheral surface of the electric wire and the inner peripheral surface of the insertion portion to prevent water from entering the electronic unit. It is possible to fix the waterproof plug to the electric wire with a simple operation by holding the waterproof plug in a lump from the outside and fixing each waterproof plug to each electric wire by this clamping. Become.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
First, a reference example of the present invention will be described based on FIGS. 1 (a), (b), and (c). The same components as those shown in FIGS . 7 and 8 are denoted by the same reference numerals, and the description thereof is omitted.
[0016]
A method for connecting the shielded cable and the electronic unit according to this embodiment is as follows.
[0017]
1) First, a shielded cable in which a sufficient gap is secured between the plurality of electric wires 12 and the common shield braid 10 that collectively covers them is manufactured. In order to manufacture such a shielded cable, for example, after forming the shield braid 10 around the electric wire group in which the plurality of electric wires 12 and the dummy wires are bundled together, the dummy wires are pulled out. That's fine. By this method, a gap can be formed inside the shield braid 10 by the amount of the dummy wire. This gap is for facilitating the following step 2).
[0018]
2) The terminal of each electric wire 12 is exposed by moving the terminal of the shield braid 10 backward to the position behind the terminal leaving the electric wire 12. Then, the ends of these electric wires 12 are peeled off to expose the inner conductor 13 as shown in FIG. 8 , and a cylindrical waterproof plug 14 made of rubber or the like shown in FIG. Fit from.
[0019]
3) The terminal fitting 16 is fixed to the end of each electric wire 12. As shown in FIG. 8 , the terminal fitting 16 also has a ring-shaped tip having a through-hole 16a, a conductor barrel 16b formed at the rear thereof, and an insulation barrel 16c formed at the rear thereof. The conductor barrel portion 16b is crimped around the inner conductor 13, and the insulation barrel portion 16c is crimped around the crimp portion 14a of the waterproof plug 14.
[0020]
4) A metal shield case 30 as shown in FIG. 1A is fixed to the end of the shield braid 10. This shield case 30 is integrally formed with a main body portion 31 having a shape that opens widely in one direction and covers the end of each electric wire 12, and a throttle portion 32 that opens on the opposite side of the opening with an area smaller than the opening. The left and right wings of the main body 31 have ears 33 projecting outward, and screw insertion holes 34 are formed in the ears 33.
[0021]
The electric wires 12 are inserted into the shield case 30 from the narrowed portion 32 side, and the end of the braid 10 is put on the outside of the narrowed portion 32 of the shield case 30. Then, the braid 10 is fixed to the narrowed portion 32 and can be electrically connected to each other by covering and crimping a caulking metal fitting (substantially O-shaped cross section) 36 from above. (State shown in FIG. 1C). In addition, the specific means for fixing the braid 10 to the shield case 30 is not limited, and welding or the like may be used as necessary.
[0022]
5) As shown in FIG. 1B, a cylindrical insertion portion 41 that communicates the inside and the outside is formed in a metal unit housing 40 that houses the circuit of the electronic unit. The end of each electric wire 12 (namely, terminal fitting 16) is inserted from the outside, and each waterproof plug 14 is press-fitted into each insertion portion 41 to form a waterproof structure.
[0023]
6) The terminal fitting 16 of each wire 12 that has entered the unit housing 40 through the insertion portion 41 is connected to an electronic circuit housed in the unit housing 40.
[0024]
7) The screw 38 is inserted from the outside into the screw insertion hole 34 of each ear 33 in the shield case 30 fixed to the end of the shield braid 10 and screwed into the screw hole 42 provided in the unit housing 40. The ear 33 is brought into contact with and fixed to the outer surface of the unit housing 40. Thereby, the connection part of each electric wire 12 and the unit housing 40 is covered from the outside by the shield case 30 and the shield case 30 and the shield braid 10 are bundled together with the housing 40 by grounding the unit housing 40. Will be ready for grounding. By this grounding, a series of shield structures from the shield braid 10 through the shield case 30 to the unit housing 40 can be formed, and high shielding performance can be ensured at the connection site.
[0025]
Next, an embodiment of the present invention is shown in FIGS.
[0026]
In this embodiment, a cylindrical waterproof plug 14 is fitted at a position slightly behind the end of each electric wire 12, and the terminal fitting 16 is directly attached to the end of each electric wire 12 at a position on the distal end side. Fix it. At that time, the insulation barrel portion 16c of the terminal fitting 16 may be crimped to the insulating coating portion of the electric wire 12 as shown. In addition, a number of circumferential grooves are formed on the surface of each waterproof plug 14 to form irregularities, and a circumferential groove 14 d is formed at the rear end of the waterproof plug 14. Further, a ring-shaped waterproof plug fixing bracket 17 is arranged behind the waterproof plug 14 and fixed around the electric wire 12.
[0027]
Next, the halved upper holder 50A and the lower holder 50B are united so as to sandwich the waterproof plugs 14 and the fixing bracket 17 from above and below to form an electric wire holder as a whole. As shown in FIG. 5, the inwardly extending ridges 52 a and 52 b that fit into the circumferential groove 14 d of the waterproof plug 14 and the fixing bracket 17 are fitted to the inner peripheral surfaces of the holders 50 </ b> A and 50 </ b> B. The concave grooves 54a and 54b are formed in advance. When the holders 50A and 50B are combined with each other in such a state, the relative positions of the electric wires 12 can be fixed, and the fixing bracket 17 and the waterproof plug 14 fixed to the electric wires 12 can be fixed. The relative position can also be fixed. That is, the waterproof plug 14 can be fixed to the electric wire 12 through the upper and lower holders 50 </ b> A and 50 </ b> B and the fixing bracket 17.
[0028]
Each holder 50A, 50B is preferably formed of an insulating material such as synthetic resin. Further, for the fixing bracket 17, for example, as shown in FIG. 6 (a), one or a plurality of ears 17a project outward from the ring-shaped main body, and the recesses 56a sandwiching the ears 17a, If 56b is formed in each of the upper and lower holders 50A and 50B, the rotation of the electric wire 12 can be restricted by the sandwiching of the concave portions 56a and 56b, so that each terminal fitting 16 fixed to the end of the electric wire 12 is provided. It is possible to always keep the through-hole 16a in an upward state, thereby making it easier to connect the terminal fitting 16 and the circuit in the unit. This effect is obtained not only by the ear portion 17a but also by configuring the electric wire holder (upper and lower holders 50A and 50B in the illustrated example) so that the fixing bracket 17 has an irregular cross-sectional shape other than a circular shape and is restrained. It is possible.
[0029]
Instead of using such a fixing bracket 17, the waterproof plug 14 can be fixed to the electric wire 12 by directly holding the electric wire 12 with the holders 50 </ b> A and 50 </ b> B.
[0030]
In this way, the electric wire holders are fitted into the main body 31 of the shield case 30 while holding the waterproof plugs 14 with the electric wire holders 50A and 50B. At this time, for example, as shown in FIG. 5, the projections 51a and 51b formed on the surfaces of the holders 50A and 50B are engaged with the holes provided on the shield case 30 side so that the holders 50A and 50B are engaged in the shield case 30. It is more preferable to stop.
[0031]
If each waterproof plug 14 is press-fitted into the insertion hole 44 formed in the unit housing 40 in this state, the relative positional relationship between the waterproof plugs 14 is previously determined by the electric wire holder. Therefore, the work of press-fitting the waterproof plugs 14 into the respective insertion holes 44 becomes easier, and the work of fixing the waterproof plugs 14 to the electric wires 12 becomes very simple.
[0032]
An example of the connection structure in the unit housing 40 is shown in FIGS. In the illustrated example, the unit housing 40 has a main body 45 that opens upward and a lid 46 that opens and closes the opening. A circuit constituted by a bus bar substrate 48 is accommodated in the main body 45, and each terminal fitting 16 is joined and electrically connected to an appropriate bus bar 48a by a screw 49.
[0033]
This connection operation can be easily performed with the lid 46 opened. Thereafter, the lid 46 is closed, and the gap between the lid 46 and the unit housing main body 45 is sealed with a rubber seal member 47 or the like, so that the bus bar circuit in the housing can be effectively protected from moisture outside the housing. .
[0034]
In addition, the present invention can take the following embodiments, for example.
[0035]
( 1 ) The unit housing 40 does not necessarily have to be formed entirely of metal, as long as at least its outer surface is formed of metal and has conductivity.
[0036]
( 2 ) In the present invention, the number and arrangement of the electric wires 12 covered by the shield braid 10 are not particularly limited, and the shape of the shield case 30 may be appropriately set according to the arrangement of the electric wires 12.
[0037]
( 3 ) In this invention, the shape of the terminal metal fitting 16 fixed to the terminal of each electric wire 12 is not ask | required. For example, a female terminal fitted to a tab terminal formed at the end of a bus bar in the electronic unit may be fixed to the end of the electric wire 12.
[0038]
【The invention's effect】
As described above, in the present invention, the shield case is connected and fixed to the end of the shield braid provided so as to collectively cover these wires on the outside of the plurality of wires, and each wire is connected to the shield case by the shield case. By fixing the shield case to the unit housing while covering the connection part with the unit housing, the shield case and the braid for shielding can be grounded together with the unit housing, so that the simple There exists an effect which can ensure high shield performance by a structure. Furthermore, since it is housed in the shield case and includes an electric wire holder that fixes the relative position of the electric wires in the shield case to a position corresponding to the relative position of the insertion portions in the unit housing , By fixing the relative positions of the electric wires, the operation of inserting each electric wire into each insertion portion of the unit housing becomes easier. Furthermore, each of the electric wires has a structure in which a waterproof plug is provided between the outer peripheral surface of the electric wire and the inner peripheral surface of the insertion portion to prevent water from entering the electronic unit. It is possible to fix the waterproof plug to the electric wire with a simple operation by holding the waterproof plug in a lump from the outside and fixing each waterproof plug to each electric wire by this clamping. Become.
[Brief description of the drawings]
1A is a perspective view showing a state in which a terminal fitting is fixed to the end of each electric wire in a reference example of the present invention, and FIG. 1B is a state in which a shield case is fixed to an end of a shield braid covering the electric wire. (C) is the sectional view on the AA line of (b).
FIG. 2 is a perspective view showing a state before the electric wire holder is attached to the waterproof plug of each electric wire in the embodiment of the present invention.
FIG. 3 is a perspective view showing a state before each electric wire is inserted into the insertion hole of the electronic unit in the embodiment of the present invention.
4 is a cross-sectional view showing an internal structure of the electronic unit shown in FIG. 3;
5 is a cross-sectional view taken along line BB in FIG.
6 (a) is a perspective view showing a preferred example of a fixing bracket used in the form of pre-Symbol embodiment, (b) is a sectional view showing a mounted state thereof.
FIG. 7 is a perspective view illustrating an example of a connection structure between a conventional shielded cable and an electronic unit.
FIG. 8 is a cross-sectional view showing an example of a structure for fixing a waterproof plug and a terminal fitting to an end of an electric wire in a shielded cable.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Shield braid 12 Electric wire 14 Waterproof plug 16 Terminal fitting 30 Shield case 31 Main body part 33 Ear part 36 Caulking fitting 40 Unit housing 41 Insertion part 42 Screw hole 44 Insertion hole (insertion part)
50A Upper holder (constitutes wire holder)
50B Lower holder (constitutes wire holder)

Claims (1)

It is a structure for connecting the electric wire of the shield cable provided with a common shield braid that collectively covers these electric wires to the outside of the plurality of electric wires, to the circuit of the electronic unit,
A terminal fitting fixed to the terminal of each electric wire and connected to a circuit in the electronic unit,
A unit housing having at least an outer surface made of metal, housing a circuit of the electronic unit, and having an insertion portion for inserting an end of each electric wire;
A metal shield case fixed to the end of the shield braid in a conductive state with the shield braid;
The shield case includes a main body portion that covers an end of each electric wire inserted into each insertion portion in an area from an end portion of the shield braid to the unit housing, and a portion that is fixed to an outer surface of the unit housing. And this part is fixed to the outer surface of the unit housing to form a state in which the shield case and the shield braid can be grounded together with the unit housing .
And a wire holder that is housed in the shield case and fixes a relative position between the wires in the shield case at a position corresponding to a relative position between the insertion portions in the unit housing,
Each of the electric wires is provided with a waterproof plug that is interposed between the outer peripheral surface of the electric wire and the inner peripheral surface of the insertion portion and prevents water from entering the electronic unit. A connection structure between an electronic unit and a shielded cable, wherein an electric wire holder is collectively held from the outside, and the waterproof plug is fixed to the electric wire side by the holding .

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