JPS5923480A - Insulator for wire connector - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to insulation of wire connections by resin impregnation.

Electrical equipment mounted on electric vehicles is subject to long-term reliability due to its responsibilities. Moreover, the voltage is 400-3000V,
Insulation plays an important role in electrical equipment that is subjected to severe electrical, mechanical, thermal, and environmental stress such as vibrations of 0.2 to 7 G and temperatures of -30 to 180"0. The crossover wire connection insulation, which is a part of the electrical insulation, is also an important part that requires high reliability.

Conventionally, the following insulation has been mainly applied to the crossover wire connection section. Broadly divided into methods that form an insulating layer without resin impregnation, and devices to be connected (e.g. insulation/illumination)
The main body is impregnated with resin to form an insulating layer. One is to polish the outlet end of the connected device 2, for example, a resin-impregnated coil attached to the frame, and weld it to one end of the crossover wire. After surface removal, a room-temperature curing epoxy compound is applied to the step.Then, the outer periphery of the joint is covered with a sodium-treated Teflon sheet, and self-fusing silicone rubber tape is wrapped several times, followed by alkali-free glass tape around the outer periphery. After winding the wire several times, a solvent-based coating is applied to the surface to complete the insulation of the connection.

However, since the insulating layer of this method is not impregnated with resin, it has the disadvantage that it is mechanically weak and easily damaged by vibration or external pressure.

In addition, since the 1-phoxy compound layer itself is a bolus solid and the varnish does not penetrate into the glass insulation,
It also has the disadvantage that it easily absorbs moisture and its insulation resistance tends to decrease. Furthermore, since the entire insulating layer is flexible, it is easy to create gaps at the interface between the conductor and the insulating layer due to vibrations when the vehicle is running.
Moisture or the like can enter from that part, causing an insulation short circuit.

The latter method will be explained using the cross-sectional view of Figure $1. The lead conductor 1 of the coil to be connected and one end 2 of the crossover wire are connected by welding. Then apply room temperature curing epoxy compound 3 thickly over the connection area and use sodium treated Teflon sheet 4.
A self-adhesive silicone rubber tape 5 is then wrapped around it several times, and an alkali-free glass tape 6 is then wrapped around it to a predetermined thickness to form an insulating layer. Thereafter, the entire object to be impregnated is preheated, impregnated with a solvent-free synthetic resin under vacuum and pressure, and cured at a specified temperature and time to complete the coil insulation and crossover wire connection part insulation. This connection insulation obtained by resin impregnation has a mechanically strong structure, but the interface between the silicone rubber coating 22 (other than silicone rubber coating cannot be used for heat resistance) that is the insulation of the crossover wire and the insulation layer. However, due to the combination of dissimilar components, the adhesion strength is poor, and vibrations caused when the vehicle is running can create gaps in the area, allowing moisture, etc. to penetrate through the gaps and penetrate into the conductor, forming a conductive path, which can lead to insulation failures. It has also become.

Furthermore, during resin impregnation, the resin infiltrates through the gaps in the crossover wire, enters the crossover wire strands 23, and hardens, causing the crossover wire to lose its flexibility and making it difficult to connect to external terminals. In some cases, it may be done. One way to make the interface between the silicone rubber coating and the insulating layer other than the epoxy compound dense is to use room-temperature curing silicone rubber, but this silicone rubber absorbs moisture from the air during curing. Because it is characterized by hardening, it is not possible to immediately wrap an airtight insulating tape around its outer circumference after application, and it is necessary to wrap insulating tape after it hardens, which causes delays in construction. ,
This was often an obstacle to short-term production.

The results of measuring the insulation resistance of this conventional insulation method when immersed in water are shown by curve A in FIG.

As soon as it is placed in water, the insulation resistance decreases.

The object of the present invention is to eliminate the above-mentioned drawbacks, and to obtain insulation for connecting wire connections that has mechanical strength, excellent heat resistance, and can form a water-resistant structure.

The present invention will be explained below using figures.

FIG. 2 shows a cross section of the crossover IfM connection insulation of the present invention.

The insulation of the coil lead-out conductor 1 to be connected and one end of the silicone rubber coated wire serving as a crossover wire is peeled off, and the part 2 to which the pressure contact terminal is attached is welded. Cooling/cleaning the welded part 10
After drying, heat-curable silicone rubber 33 is applied uniformly to the outer periphery, the exposed conductor portion, and a part of the silicone rubber coating 22 so as to avoid uneven coating. After coating, the outer periphery is covered with one or more sodium-treated Teflon sheets 4 having a thickness of 0.05 to 1.0 m, and a layer of 0.1 to 1.0 m thick
A self-fusing silicone rubber tape 5 of 1.0% is wound to a predetermined thickness, and further a thickness of 0.07 to 0.38 is wrapped around the outer circumference.
An insulating layer is formed by wrapping urn's alkali-free lath tape 6 to a predetermined thickness.

Next, the entire electrical equipment is preheated in a constant temperature bath set at 70 to 130 degrees. By preheating, the moisture contained in the insulating layer is removed, the viscosity of the resin to be impregnated later is lowered, and the impregnating properties are improved. In addition, the silicone rubber 33 filled in the insulating layer at the crossover wire connection part is hardened. Complete.

After the preheating is completed, the electrical equipment is left in the impregnation container, and after being carried into the impregnation tank, it is impregnated with synthetic resin under vacuum and pressure at a predetermined temperature, pressure, and time. After the impregnation is complete, the electrical equipment is removed from the resin-filled impregnation container and cured by heating at a specified temperature and time.

The insulation of the crossover wire connection portion of the electrical equipment thus obtained is mechanically strong and can withstand external pressure and vibration. Conventionally, the interface between silicone rubber, which is the cable covering where moisture etc. has the highest possibility of infiltration, and the connection insulating layer are strongly bonded by using a silicone rubber coating of the same composition, and furthermore, the insulating layer itself is made of impregnated resin. Combined with the increased strength, it completely prevents moisture from entering and maintains high reliability over a long period of time. Further, by adopting such a configuration, there is an advantage that the construction period is shorter than that of the conventional method, and since it is possible to prevent the resin from penetrating into the crossover wire, it also has the advantage of smoothing the work in the subsequent process.

In an example using insulation according to the present invention, the following results were obtained.

This is the case for insulating the connections of a 210 KVA exciter generator reactor mounted on a vehicle. Use a Nomex coated conductor with a cross section of 35 x 65 mm, or strip off the Nomex cover at one end of the coil opening of the accelerator to expose the conductor. On the other hand, the cable sheathing of the connecting cable (silicone rubber coated cable with glass sheath) was
After stripping 111 and exposing the copper wire, a 25-inch long copper pipe is inserted and crimped. This was overlapped with one end of the previous coil opening by 25txm, and then welded with a chisel weld, the corners were polished, and then washed and dried. After drying, apply heat-curable silicone rubber uniformly to the welded parts, exposed conductor parts, and the silicone rubber coating of the cable to a thickness of 0 before curing.
5 Wrap a sodium-treated Palfron sheet (Nippon Palcar brand name) with a width of 60IIl111 once. Next, wrap self-adhesive Palcon tape (Nippon Palcar brand name) with a thickness of 0.38mm and width of 30m once in a half overlap so that it covers the outer circumference of the Palflon sheet and 15mm on each side of the sheet, and then The thickness of the outer periphery is 0.1311111. Width 19
Wrap am's alkali-free lath tape twice, half overlapping, to form an insulating layer. After forming the insulating layer, the reactor was preheated at 120°0 for 10 hours, slowly cooled to 50°0, placed in an impregnating container, transported to an impregnating tank, poured with two heat-resistant bisphenol-based epoxy resins, and heated under vacuum. Perform pressure impregnation. After completing the impregnation treatment for about 90 minutes, the reactor was taken out from the impregnation container, and after allowing any remaining drops to fall, heat curing was performed at 160° 0 for 15 hours. Underwater immersion of reactor insulation including connection insulation obtained in this way
The results of measuring the insulation resistance are shown in curve 8 in FIG.

In the insulation resistance measurement of the crossover wire connection part of the electrical equipment of the present invention when immersed in water as shown in the example, it was confirmed that the insulation resistance did not decrease even after being immersed for 48 hours and showed sound insulation properties. It has been found that this constitutes an insulation which satisfactorily satisfies the purpose.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional connection part insulation structure, and FIG. 2 is a sectional view of a connection part insulation structure according to the present invention. FIG. 3 is a time-dependent characteristic curve of the underwater insulation resistance of the conventional and inventive joint insulations. 1. Coil lead-out conductor; 2. Crossover wire tip pressure contact part,
3 Ethoxyco V /< +7nd, 4, Teflon Sea), 5. p silicon rubber tape 6, glass tape 11. Coil insulation layer, 22, silicone rubber coating, 3
3. Silicone rubber (heat curing type) (7317) Agent Patent attorney Kensuke Norichika (one idiot) Figure 1 Figure 2

Claims (1)

[Claims] Apply heat-curable silicone rubber to the surface of the wire connection,
An insulator for wire connections is formed by sequentially wrapping a sodium-treated Teflon sheet, a self-bonding silicone rubber tape, and an alkali-free glass tape on top of it, heating and drying it, then impregnating it with a solvent-free synthetic resin and curing it.