Talking about the composition and function of automotive electrical circuit connection connector

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1.1 Wire

Automobile electrical equipment is connected to the power supply, control switch and protection devices through wires. Wires are the basic components of automobile electrical circuits. The wires used in automobile circuits are all multi-strand copper wires.

(1) Conductor cross-sectional area. The cross-sectional area of ​​the conductor is determined according to the current value of the connected electrical equipment. In order to ensure that the conductor has sufficient mechanical strength, the cross-sectional area is not less than 0.5m2. The allowable current carrying values ​​of the nominal cross-sectional area of ​​various low-voltage conductors are shown in Table 1. Table 1 Allowable current carrying values ​​of the nominal cross-sectional area of ​​automotive low-voltage conductors The nominal cross-sectional area of ​​the conductor is the cross-sectional area value obtained according to the prescribed conversion method. It is neither the geometric area of ​​the wire core nor the sum of the geometric areas of each strand of copper wire.

(2) Wire color. For the convenience of wiring and maintenance, the wires of each circuit of the car are distinguished by different colors. my country generally requires that wires with a cross-sectional area of ​​more than 4.0 mm2 be single-color, and other wires be double-color (with a secondary color strip on the basis of the main color). The basic principle of wire color matching is that the main color of the double-color wire and the single-color wire in the same electrical system should be the same; the secondary color of the circuit branch line should be selected according to the allowed color. Some cars use more wires, and for the convenience of wiring and identification, they are often covered with a certain color of casing at the joint of the wire. Understanding the color matching rules of the car circuit wires is very helpful for fault detection.

(3) Wire color code. To facilitate circuit identification and maintenance, wire color codes are usually marked on the wire terminals and circuit diagrams. The International Organization for Standardization stipulates that English letters of various colors are used as wire color codes. my country, the United Kingdom, the United States, Japan, etc. all use English letters, but some countries also use their native language letters as wire color codes. The marking method for two-color wires in automobile circuit diagrams is that the primary color is in front and the secondary color is in the back. For example, "Bw" means that the primary color of the wire is black and the secondary color is white. There is also a marking method that adds "/" or "-" between the primary and secondary color codes.

In some car circuit diagrams, the cross-sectional area of ​​the wire is also marked. For example, "1.5Y" means that the cross-sectional area of ​​the wire of this line is 1.5mm2 and the wire color is yellow. For car wires with sleeves, the color of the wire sleeve is usually marked in the circuit diagram. For example, Japanese cars use color codes composed of English letters to mark the colors of wires and sleeves as follows:

1.2 Line connection connector

(1) Composition and function of the connector. The connector, also known as the connector, consists of a plug and a socket, and is used to connect electrical equipment to the circuit and between circuits. Compared with the old-fashioned single-wire connection method of the terminal, the connector connection method has the advantages of convenient and quick wiring, simple and compact wiring harness structure, and avoidance of wiring errors. It has been widely adopted by modern cars. To ensure reliable connection, the connector is usually equipped with a locking device and has good sealing to prevent oil, water, dust, etc. from entering and causing rust to the connector terminals.

(2) Connector identification. Connectors used in different locations on a car have different numbers of terminals, geometric dimensions, and shapes, so they cannot be plugged in incorrectly. However, modern cars use multiple line connectors, which may have the same number of terminals and the same shape. For this reason, the outer surfaces of some car line connectors are painted with different colors to facilitate fault finding and avoid connection errors.

Different countries and car companies have different ways of representing connectors in their circuit diagrams, but the numbers in the squares all represent the numbers of the connectors. Some car circuit diagrams use black to represent plugs, and non-black to represent sockets; chamfers indicate that the plug pins are columnar, and right angles indicate that the plug pins are sheet-shaped.

In order to facilitate wiring, wiring cards are welded on the ends of each wire in the automotive wiring harness, and insulating tubes are placed at the connection between the wire and the wiring. The wiring cards that are frequently disassembled are generally open-ended, while the wiring cards that are rarely disassembled are often closed. Plug connectors are now used on domestic new cars and foreign cars, which is beneficial to the manufacture of cars and more conducive to maintenance. The plug connector consists of two parts, a plug and a socket, and the number of pins varies according to the actual needs of the occasion. The plug pins are divided into flat ends and needles. Figure 2 shows the physical objects and symbols of two different forms of four-pin plug connectors. When the plug connector is connected, its guide grooves should be overlapped first, so that the plug and the socket are aligned and inserted with a little force, so that they can be connected very firmly. The so-called guide groove of the plug connector refers to the convex and concave rails set to correctly position the plug connector when it is connected. A pair of plugs and sockets generally cannot be inserted incorrectly due to the role of the guide groove. Non-paired plugs and sockets will not have the same number of pins and external shapes, so they cannot be inserted incorrectly. Therefore, it is very convenient and reliable to use a plug connector to connect the circuit.

In order to prevent the connector from being disengaged during the driving of the car, all connectors are equipped with locking devices. When you want to remove the connector, you should first press the lock and then pull it open. Never pull the wire hard without pressing the lock to prevent damaging the lock or the wire.

1.3 Circuit diagram

Circuit diagrams are used to show the approximate location and wiring of automotive electrical appliances, and are relatively intuitive. The disadvantage of circuit diagrams is that the lines are dense and crisscrossed, making line search and circuit analysis relatively complicated. Especially for cars with many electrical devices, it is even more complicated to use circuit diagrams to represent the entire vehicle's electrical system. Therefore, it is rare to use circuit diagrams to represent the electrical system of a modern car. It is common to use circuit diagrams to represent the entire vehicle's electrical system or part of the circuit principle.

Wiring

The wiring harness is made of wires in the same direction. Wrapping multiple strands of wire into a wiring harness can make the line less messy, facilitate installation, and protect the wires. Modern cars use inter-wire connectors to increase the strength of the wiring harness design, and the number of wiring harnesses is also large. The use of these highly targeted and relatively small wiring harnesses brings convenience to the installation, maintenance and replacement of automobile lines.