RU2760565C1 - Method for sealing low-frequency connectors of electrical harnesses and cables - Google Patents

Abstract

FIELD: electronic equipment.

SUBSTANCE: invention relates to electronic equipment, namely to methods for sealing low-frequency connectors of electrical harnesses and cables, and can be used in the design of low-frequency sealed units of cable connectors. The method consists in filling the inner space of the connector with a sealant after installing the connector and degreasing the wires, is carried out in several stages and is based on the combined use of elastic and rigid materials of various viscosities, and at the first stage, the contact part of the connector from the side of the wires is filled with elastic sealant, the wires coming out of the connector, lubricate with an elastic sealant to the length of the heat-shrinkable tube, which is shifted onto the connector branch pipe, and the excess sealant that goes beyond the heat-shrinkable tube is removed.

EFFECT: ensuring high-frequency tightness of low-frequency connectors, improving their operational and technical characteristics by eliminating mechanical stresses in the places of wire rations and contacts at temperature differences, vibration influences, ensuring absorption of high-frequency interference - parasitic signals.

1 cl, 2 dwg

Description

The invention relates to electronic equipment, in particular to methods of sealing low-frequency connectors of electrical harnesses and cables, and can be used in the design of low-frequency sealed units of cable connectors to increase the reliability of their operation with the exception of wire breakage during vibration, moisture protection of installation, as well as high-frequency tightness in devices of electronic equipment of various types of basing.

From the prior art, a method is known for pouring subminiature connectors of the PC, MP type to increase the reliability of their operation in terms of eliminating wire breakage during vibration, moisture protection of installation, as well as to reduce weight (OST4 GO.010.016 p. 93, 94 p. 6.5.10., p. 98 Fig. 111), which consists in the unpackaged filling of the connectors by filling the space between the wires after mounting the connector with a thermosetting compound, for example, the EZK-6 brand or an equivalent using a syringe when placing the connector with wires in a special mold, consisting of two semi-matrices.

The disadvantage of this method is that the existing technology is based on the use of one filling material, which is due to a number of disadvantages, for example:

- the use of silicone materials - in the form of filling materials, which have low adhesion to surfaces and high shrinkage, which affects the degree of mixing of the components, for example, paste and catalyst and, as a result, non-solidification of the sealant areas. To eliminate this drawback, thinners are used (in accordance with OST 4GO.053.213-83), while the more thinner, the greater the shrinkage. A negative factor in increasing shrinkage is the separation of the sealant from the wires and, as a result, the connector is leaking;

- the use of a rigid epoxy and polyester compound, in the form of a filling material, while stresses arise during curing, which leads to a break in the conductors at the desoldering points, and also does not provide high-frequency sealing (ensuring the absorption of high-frequency interference - parasitic signals).

The closest in technical essence and the achieved results to the proposed technical solution is a method of sealing low-frequency connectors of electrical harnesses and cables (RF patent for invention No. 2540325, IPC: H02G 15/08, 2013), which consists in filling the inner space of the connector with sealant after installing the connector and degreasing the wires, while filling is carried out in three stages and is based on the combined use of elastic and rigid materials of various viscosities, and at the first stage, the contact part of the connector from the side of the wires is filled with an elastic sealant, which is also applied to the places of contact of the body with the connector branch pipe, tighten the branch pipe nut the connector and after curing the sealant for 15-24 hours, the entire volume of the connector branch pipe from the wire side is filled with a filling compound flush with the edge of the branch pipe, after which the compound cures for 24 hours, then the wires coming out of the connector are lubricated with elastic herme teak to the length of the heat-shrinkable tube, which is shifted onto the connector branch pipe, the excess sealant that goes beyond the heat-shrinkable tube is removed, and the sealant cures in 15-24 hours.

The above-described sealing method is used for sealing connectors, which is due to their structure, for example, the presence of a housing for low-frequency connectors of the 2RM type with an electrical harness or cable that ensures their reliability with the exception of wire breakage during vibration, moisture protection of the installation, while it does not provide high-frequency tightness, in the presence of a complex technical process and, as a consequence, its high labor intensity.

The technical problem solved by the creation of this method is to provide high-frequency sealing.

The technical result, which the claimed method of sealing low-frequency connectors of electrical harnesses and cables is aimed at, is to ensure high-frequency tightness of low-frequency connectors, improve their operational and technical characteristics, by eliminating mechanical stresses in the places of wire rations and contacts at temperature differences, vibration effects, ensuring absorption of high-frequency interference - parasitic signals.

The technical result is achieved by the fact that the method of sealing low-frequency connectors of electrical harnesses and cables, which consists in filling the inner space of the connector with a sealant after installing the connector and degreasing the wires, is carried out in several stages and is based on the combined use of elastic and rigid materials of various viscosities, and at the first stage, the contact the part of the connector from the side of the wires is filled with an elastic sealant, the wires coming out of the connector are lubricated with an elastic sealant for the length of the heat-shrinkable tube, which is shifted onto the connector branch pipe, and the excess sealant that goes beyond the heat-shrinkable tube is removed.

Unlike the prototype, at the first stage, a part of the branch pipe, fixed on the threaded part of the connector, is filled with an elastic sealant with high adhesion and low viscosity to a height H, which is selected from the condition:

Н≥d,

where d is the largest diameter of the wire in the insulation.

The curing of the elastic sealant is carried out during the time T, selected from the condition:

T = 2 / 3t,

where t is the time of complete curing of the sealant.

At the second stage, it is filled with ferrite powder, which forms a disc with a height of H1, which is selected from the condition:

H1≥Н, while

H1 = L / K,

where L is the amount of screening (losses of the "parasitic" microwave signal),

K is the specific coefficient, inversely proportional to the wavelength λ and the size of the powder granules, determined empirically.

At the third stage, it is filled with a hard sealant containing at least 70% of ferrite powder to a height of H2, which is selected from the condition:

H2≥H1,

in this case, further filling of the nozzle is possible by alternating ferrite powder and hard sealant.

At the fourth stage, the wires coming out of the connector branch are lubricated with an elastic sealant, and the heat shrinkage of the thermotube is performed, the excess sealant that goes beyond the thermotube is removed.

The essence of the invention is illustrated by drawings, where:

FIG. 1 is a general view of a low-frequency sealed connector assembly for electrical harnesses and cables;

FIG. 2 is a general view of the height of the placement of the components of the seal.

The unit of the low-frequency sealed connector of electrical harnesses and cables contains a housing 1 (Fig. 1) of the connector, an insulator 2 (Fig. 1) of the connector, contacts 3 (Fig. 1) of the connector, wires 4 (Fig. 1), a branch pipe 5 (Fig. 1) ), nut of the branch pipe 6 (Fig. 1), elastic sealant 7 (Fig. 2) ferrite powder 8 (Fig. 2), hard sealant 9 (Fig. 2), heat shrink tube (hereinafter - thermotube) 10 (Fig. 1) ...

The proposed method for sealing low-frequency connectors of electrical harnesses and cables, as well as high-frequency sealing is as follows.

Before the start of sealing, the insulation is removed from the wires 4, the contacts 3 are crimped on the cores of the wires 4 in accordance with the recommendations of the TU for the connector. Install contacts 3 with wires 4 into insulator 2, which is located in the housing 1 of the connector, degrease wires 4, the surface of the insulator 2 of the connector from the side of wires 4 and the inner surface of the branch pipe 5, then screw the nut of the branch pipe 6 onto the threaded part of the housing 1 of the connector.

First stage.

The branch pipe 5, fixed on the threaded part of the housing 1 of the connector with the nut of the branch pipe 6, is filled with an elastic sealant 7 with high adhesion and low viscosity to a height H (Fig. 2), which is selected from the condition:

H> d,

where: d (Fig. 2) - the largest diameter of the wire in the insulation. Curing of the elastic sealant 7 is carried out within T - hours, selected from the condition:

T = 2 / 3t,

where t is the time of complete curing of the sealant.

The role of the first stage of sealing is to level the mechanical stresses at the points of entry of wires 4 into contacts 3 and them into insulator 2 during temperature differences, vibration effects and moisture protection of the installation, as well as to create an adhesion surface for the second stage.

Second stage.

Part of the branch pipe 5 is filled with ferrite powder 8 forming a disk with a height H1 (Fig. 2), which is selected from the condition:

H1≥Н, while

H1 = L / K,

where L is the amount of screening (losses of the "parasitic" microwave signal),

K is the specific coefficient, inversely proportional to the wavelength λ and the size of the powder granules, determined empirically.

The role of the second stage of sealing is to form a disk of ferrite powder 8 to ensure high-frequency sealing, in order to increase it, vibration compaction of ferrite powder 8 is performed, for example, on a vibration table with sinusoidal vibration 2g, which is due to the adhesion of particles of ferrite powder 8 to each other, as well as to elastic sealant 7 of the first stage and its even dense distribution between the wires 4.

Third step.

Part of the pipe 5 is filled with a hard sealant 9 containing at least 70% of ferrite powder to a height of H2 (Fig. 2), which is selected from the condition:

H2≥H1,

in this case, for example, it is possible to further fill the pipe by alternating ferrite powder 8 and rigid sealant 9 (Fig. 2).

In contrast to the first stage, in this case, a sealant with a higher viscosity in the form of a rigid sealant 9 is used in order to uniformly fix the ferrite powder 8 in the filled volume. The hard sealant 9 fixes the surface layer of the ferrite powder 8 disc by its penetration into its surface.

Fourth step.

The wires 4 coming out of the branch pipe 5 of the connector 1 are lubricated with an elastic sealant 7, for example, to a length equal to the length of the thermotube 10 (Fig. 2). The thermal tube 10 is shifted onto the branch pipe 5 of the connector 1, while heat shrinkage is performed. Due to mechanical compression of the thermotube 10, the elastic sealant 7 fills all the voids between the wires 4, and the excess sealant extending beyond the thermotube 10 is removed.

The role of the fourth stage of sealing is to perform the functions of a damper of the wires 4 of the cable during vibration loads, to ensure control of the minimum radius of its bending at the exit from the branch pipe 5.

An example of using a low-frequency sealed cable connector unit can be a connector in which an SNTs 144 plug can be used as the contact part of the connector 1, with a cable assembled from separate wires 4, for example, of various diameters with contacts 3 of this plug, crimped on the wires 4 of the cable.

This method of sealing low-frequency connectors of electrical harnesses and cables, due to the fact that the method is carried out in four stages and is based on the combined use of elastic and rigid sealants of various viscosities, using at the first stage an elastic sealant with incomplete curing, and at the second and subsequent stages with alternating ferrite powder in the form of a disk and a hard sealant containing at least 70% ferrite powder, provides high-frequency tightness of low-frequency connectors with cables and bundles in a wide range of climatic and mechanical influences due to the elimination of mechanical stresses in the places of wire rations and contacts at temperature extremes, vibration influences, ensuring the absorption of high-frequency interference - parasitic signals.

Claims (15)

The method of sealing low-frequency connectors of electrical harnesses and cables, which consists in filling the inner space of the connector with a sealant after installing the connector and degreasing the wires, is carried out in several stages and is based on the combined use of elastic and rigid materials of various viscosities, and at the first stage, the contact part of the connector from the side of the wires is filled elastic sealant, the wires coming out of the connector are lubricated with elastic sealant to the length of the heat-shrinkable tube, which is shifted onto the connector branch pipe, and the excess sealant extending beyond the heat-shrinkable tube is removed, characterized in that at the first stage, part of the branch pipe fixed on the threaded part of the connector , filled with an elastic sealant with high adhesion and low viscosity to a height H, which is selected from the condition: Н≥d, where d is the largest diameter of the wire in insulation; curing of the elastic sealant is carried out during the time T, selected from the condition: T = 2 / 3t, where t is the time of complete curing of the sealant; at the second stage, it is filled with ferrite powder, which forms a disk of height H1, which is selected from the condition: H1≥Н, while H1 = L / K, where L is the amount of shielding (losses of the "parasitic" microwave signal), K is the specific coefficient, inversely proportional to the wavelength λ and the size of the powder granules, determined empirically; at the third stage, it is filled with a hard sealant containing at least 70% of ferrite powder to a height of H2, which is selected from the condition: H2≥H1, in this case, further filling of the nozzle is possible by alternating ferrite powder and hard sealant; at the fourth stage, the wires coming out of the connector branch are lubricated with an elastic sealant and heat shrinkage of the thermotube is performed, and the excess sealant that goes beyond the thermotube is removed.

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