The environment is more complicated when the wiring harness is routed outside the car. In order to better protect the wires, it is necessary to use reasonable coverings outside the wires to protect the wear. The coverings can play a role in prevention, early warning, earthquake, early warning, etc., so that the wires can be used normally in the environment. This article mainly introduces the selection of high-voltage wiring harness coverings. The following is the main text.
Types and characteristics of high-voltage wiring harness coverings
The main high-voltage wiring harness coverings include corrugated tubes, sleeves, wear-resistant tapes and thermal insulation sleeves. In the selection of high-voltage wiring harness coverings, corrugated tubes, sleeves and wear-resistant tapes are transparent choices.
1.1 Corrugated tubes
Corrugated tubes are almost widely used in high-voltage wiring harness protection. Generally, high-voltage wiring harness coverings can be round tubes, and the color is orange. In addition to the common round corrugated tubes, there are also elliptical corrugated tubes, which are suitable for the situation of multi-line common corrugated tubes.
There is a specific formula for selecting the diameter of the corrugated pipe, that is, the diameter of the corrugated pipe = the outer diameter of the conduit / 0.92 (for multi-strand wires, the outer diameter of the wire is the outer common tangent circle diameter).
Generally speaking, it is best to use a closed-end corrugated pipe for the corrugated pipe, and the difference between the inner diameter of the corrugated pipe and the outer diameter of the cable is ≤5mm; for heights below 300mm, an open corrugated pipe can be used, and the two ends and the middle of the open corrugated pipe are wrapped with PVC tape.
For example:
A high-voltage wire cable is 50mm², and the outer line of the wire is 13.97mm, which matches its corrugated pipe.
For a single-core wire corrugated pipe, the diameter of the corrugated pipe used is = 13.97/0.92 = 15.18mm, so the corrugated pipe should be selected with an inner diameter greater than 15.18mm and close to the inner diameter. For example, a corrugated pipe with an inner diameter of 16.00/15.37mm.
1.2 Sleeves
The sleeves can effectively prevent harness fatigue. Compared with bellows, the sleeves have higher wear resistance and smaller outer diameter, but the cost will be different.
The sleeves should be orange in color. There are open self-rolling and closed types. The open self-rolling type is easy to install. When choosing the open self-rolling type, it should be noted that the overlap rate of the curling should reach 30% (range). The specific overlap rate of the curling needs to be determined with the corresponding supplier.
1.3 Wear-resistant tape
Compared with bellows and sleeves, wear-resistant tapes are easy to use, increase the outer dimensions of the harness to the smallest, and hardly affect the outer dimensions of the harness. The cost is higher. However, it is rarely used under normal circumstances and is suitable for situations where the environment requirements are not high, such as in the cable trough, inside the equipment end, etc.
1.4 Heat insulation
Manhattan can effectively protect the weather forecast of the high-voltage harness and ensure the normal operation of the harness. Excessive temperature will affect the normal operation of the high-voltage harness. To avoid such situations, an early warning should be used when the harness is located in a high temperature area.
If the wiring is near the three-way catalytic converter or parallel to the exhaust pipe and the gap is less than 100mm, thermal insulation protection must be done.
Common heat sources include exhaust pipes, EGR exhaust gas recirculation valves, oxygen sensors, three-way catalytic converters, etc.
Comparative analysis of the wear resistance and cost of wiring harness covers
As mentioned above, in the selection of high-voltage wiring harness covers, bellows, sleeves and wear-resistant tapes are common choices. Below we use this transparent cover to compare the wear resistance and cost to provide a reference for the selection of high-voltage wiring harness covers.
2.1 Wear resistance comparison
1.Wear-resistant tape: Compared with bellows and sleeves, wear-resistant tape has the lowest wear resistance. It is rarely used under normal circumstances and can be used in situations where the environment requirements are not high, such as in the wire slot and inside the equipment end.
2.Bellows: Generally, high-voltage wiring harnesses can use bellows, which have wear resistance and wear tiles. Corrugated tubes are widely used in wire harness protection. In addition to the common circular corrugated tubes, there are also elliptical corrugated tubes, which are suitable for the situation where multiple wires share the same corrugated tube.
3.Sleeve: The sleeve has the highest wear resistance. Compared with the groove tube, it can more effectively prevent the wear of the wire harness. The sleeve is divided into open self-rolling and closed. For the open self-rolling installation, the overlap rate of the curling edge should reach 30% (range). The specific overlap rate of the curling edge needs to be determined with the corresponding supplier.
2.2 Cost comparison
1. Abrasion-resistant tape: The lowest cost. Because it is easy to use, the added wire harness size is the smallest, and it hardly affects the wire harness size, so it is an economical choice in some environmental conditions where the requirements are not high.
2. Corrugated tube: The cost is moderate. The price of the corrugated tube is affected by many factors, such as material cost, production process and technology, market competition, etc. Generally speaking, the price of mid-range corrugated tubes is around 200-500 yuan/meter.
3. Sleeve: The highest cost. Although the sleeve has higher wear resistance and smaller outer diameter, the cost is relatively high.
In summary, in the selection of high-voltage wire harness covers, the appropriate cover should be selected according to the specific working environment and needs.
- If the working environment requirements are not high, wear-resistant tape can be selected;·
- If better wear resistance and moderate cost are required, corrugated tube can be used;
- If the wear resistance is extremely high and cost factors are not considered, sleeves can be used.
At the same time, other factors such as installation convenience and appearance requirements can be combined for comprehensive consideration to ensure that the high-voltage wire harness is effectively protected in different environments.
Key points of high-voltage wire harness cover options
3.1 Consider the working environment
When selecting high-voltage wire harness covers, factors such as working environment, space size and special functions need to be fully considered.
The temperature requirements of different parts of the vehicle are different, which requires the design of the high-voltage wire harness to be adjusted according to the specific temperature conditions to ensure normal operation in various environments. The working temperature of the high-voltage wire harness refers to the temperature range within which the product can work stably for a long time and maintain normal characteristics.
Near the internal combustion engine with the highest temperature and increased vibration, PA or PP corrugated tubes with good flame retardancy, corrosion resistance and good mechanical properties are ideal choices. After the high-voltage wire harness is wrapped with a corrugated tube, the outer periphery should also be wrapped with PVC tape for sealing to ensure better protection.
For different working environments, covers with different characteristics need to be selected. If the working environment temperature is high and the gap between the high-voltage wire harness and the heat source is less than 100mm, the initialization bracket is necessary.
3.2 Consider the appearance color of the cover
The appearance color of the high-voltage wire harness is usually orange.
This color has a specific purpose of selection. On the one hand, it can serve as a warning to remind people to pay attention to the existence of the high-voltage wire harness and avoid accidental touch; in addition, the uniform color can also quickly identify the high-voltage wire harness during vehicle maintenance and inspection.
Summary
In addition to mastering the type and characteristics of the cover, the selection of high-voltage wire harness covers also requires in-depth understanding of the working environment of the wire harness layout area, such as the working environment temperature, wear resistance requirements, etc. Only by combining the working environment's demand for coverings with the characteristics of the covering product itself can the selection of coverings be made properly.