Starting from the four basic structures of automotive connectors, the design standards of automotive connectors are introduced. In view of the stability evaluation of automotive connectors, three failure modes of automotive connectors are analyzed, and the characteristics of automotive connectors are interpreted. The development and change situation, and finally, according to the market demand brought by this development and change, the corresponding automotive connector application examples are given.

The form and structure of automotive connectors are ever-changing. They are mainly composed of four basic structural components: contact parts, housings (depending on the variety), insulators, and accessories. These four basic structural components enable the automotive connector to act as a bridge for stable operation.

Contacts are the core parts of automotive connectors to complete the electrical connection function. The contact pair is generally composed of a positive contact and a negative contact, and the electrical connection is completed by the mating of the female and male contacts. The male contact is a rigid part and its shape is cylindrical (round pin), square cylinder (square pin) or flat (pin). The male contact is generally made of brass or phosphor bronze. The female contact is the key part of the contact pair. It relies on the elastic structure to elastically deform when mating with the pin to generate elastic force to form close contact with the male contact to complete the connection. There are many types of jacks, including cylindrical (slotted, narrowed), tuning fork, cantilevered (longitudinal slotted), folded (longitudinal slotted, 9-shaped), and box-shaped (square socket) And hyperboloid wire spring jacks.

The shell, also known as the shell, is the outer cover of the automotive connector. It provides mechanical protection for the built-in insulation mounting plate and pins, and provides alignment when the plug and socket are mated, thereby securing the connector to the device. on.

Insulators are also often called automobile connector bases or mounting plates. Its role is to arrange the contacts at the required position and spacing, and to ensure the insulation performance between the contacts and between the contacts and the housing. Good insulation resistance, voltage resistance and easy processability are the basic requirements for selecting insulating materials for processing into insulators.

Accessories are divided into structural accessories and installation accessories. Structural accessories such as collars, positioning keys, positioning pins, guide pins, coupling rings, cable clamps, seals, gaskets, etc. Installation accessories such as screws, nuts, screws, spring coils, etc. Most of the accessories are standard parts and universal parts.

With the rapid development of the automotive industry, various functional parts and various components on automobiles are constantly developing towards intelligence, refinement and reliability. The structural design, appearance design and materials of automotive connectors have also been proposed. Higher requirements have certain design standards.

标准 Design standards for automotive connectors

Automotive connectors must meet the USCAR-20 standard, which is the performance standard for automotive electrical connector systems. It requires that the electrical connector contact surface of the automotive connector be reliable throughout the entire life cycle, including the following nine factors:

1) The material of the connector contacts is stable and reliable;

2) The forward force is stable;

3) The voltage and current of the circuit are stable;

4) The temperature requirement is within the specified range, including the surrounding temperature and its own temperature rise;

5) better robustness;

6) It must be the same as the connector for high-speed long-distance communication computer, and the automotive connector must be able to work reliably under harsh conditions;

7) Connector insertion force: below 20.5kg;

8) Connector holding force: 2.5kg or more;

9) Heat resistance: -40 ~ 120 ℃

典型 A typical light vehicle has approximately 1,500 connection points, of which 50% to 60% are used for critical power distribution functions. Automotive connectors are used in increasingly harsh environments, including temperature (down to minus 40 ° C, up to minus 155 ° C), vibration, oxidation and friction corrosion, which shows the importance of design.

In fact, this is not easy to do. Most commercial electronic components can be upsetting and frustrating when they fail. However, if there is a problem with the connection of key automotive parts, it will cause the fire alarm, brake or airbag to fail. Lead to serious consequences.

Connector manufacturers must identify and analyze physical and mechanical phenomena in the environment that may affect connector performance. In order to evaluate the stability of the connector, the connector manufacturer has implemented a detailed test procedure in accordance with the application conditions specified by the car manufacturer. In the event of a connector failure, most of them can be identified as one of three failure modes: friction corrosion, electrical failure, and connector plug problems. The following is an introduction to these three failure modes.

Three failure modes of automotive connectors

Corrosive gas, high humidity, and strong oscillations are the three major conditions that cause oxidation and frictional corrosion, and cause connector failure. These environmental factors can greatly affect the contact surfaces of tin and lead-tin, which is the case for 90% of connector surfaces.

Cable and terminal connection problems are one of the main causes of warranty and connector system failures. For automotive wiring systems, crimping is a very common method for connecting terminals to cables. This process has proven reliable. Compared with the welding method, it is more economical and easy to operate in terms of improving crimp reliability.

时 When wiring is installed in the car at the assembly plant, improper plugging of the connector may cause the connector to malfunction. To overcome this problem, design engineers have developed a variety of connector locking devices. Another method is to use a plug assist device to simplify the plug process for larger connectors.

Detailed understanding of automotive connector failure modes, please refer to the analysis of three failure modes of connector durability

As consumers have more and more requirements for the internal electronic functions of automobiles, and more and more electronic functions can be provided inside automobiles, automotive connectors have become the fastest-growing segment of automotive parts. The following is a summary of the development of automotive connectors.

Development and changes of automotive connectors

At present, the global automotive connector industry accounts for about 15% of the connector industry. It is expected that in the future, driven by automotive electronics products, it will occupy a larger proportion. In terms of product cost structure, the average connector cost per car in China now is only a few hundred yuan, and the connector cost per car with foreign countries is about $ 125 to $ 150. From the perspective of the Chinese automotive connector market, Great development potential. In the future, 600-1 (＄ 4.4400) electronic connectors will be used per car, which is much larger than the number used today.

The huge potential of the market has attracted great attention from foreign manufacturers. Major automotive electronics companies such as Tyco, Delphi, and FCI have stepped up their investment and layout in the Chinese connector market. Delphi has even moved its center of automotive connector business to Shanghai. China is expected to become an important production base for global automotive connectors in the future. In addition to the existing first-line well-known international manufacturers, other manufacturers who have not yet set up factories in China will gradually establish production bases in China to supply local auto component manufacturers due to the continuous increase in local demand, localized procurement, and cost advantages. need.

In addition, electric vehicles and hybrid vehicles use large-capacity lithium batteries, and their operating voltage ranges from 14V to 400V to 600V for conventional cars. Therefore, the overall improvement of automotive electronic and electrical architecture is required, and connectors are the first. The new energy vehicle connector market has become a large niche market.

的 The three major trends in the development of new energy vehicle connectors are: first, green, second, safety, and third, connectivity.

Since new energy vehicles are "green" vehicles, the connectors also require green environmental protection. In terms of safety, as new energy vehicle connectors have the ability to withstand 250A current and 600V voltage at the highest, the demand for high standard protection against electric shock is obvious. At the same time, at such high power, electromagnetic interference is another important issue. In addition, the plugging and unplugging operation of the connector can generate arcs, which can seriously harm electrical connections and electronic equipment, and can cause automobile combustion. These require special design and development of connectors.

To meet the high performance requirements of new energy automobile connectors, they mainly rely on strict design specifications. For example, to prevent high-voltage breakdown of air under exposed conditions, this requires maintaining a certain air gap. In the case of high voltage and high current, its The temperature rise cannot exceed the rated value; weight, strength and ease of processing must be considered when selecting the housing material, and how to maintain the stability of the material properties of the connector terminals at different temperatures and how to ensure the necessary conductivity must be considered.

In terms of connectivity, the importance of high-speed data transmission functions has become increasingly prominent due to the continuous expansion of automotive entertainment systems. For example, on some models, a camera is installed on the reversing mirror to allow the driver to have a wider field of view, which requires connectors to transmit more data. Sometimes a connector is needed to solve the problem of transmitting GPS signals and broadcast signals at the same time, which requires improving its data transmission capabilities. At the same time, the connector also needs to withstand high temperature, because the car engine is usually placed in front of the car, and although there is a firewall to protect it, there will still be some heat transmitted, so the connector must be able to withstand high temperature.

With the increasing application of automotive connectors, the integration of automobiles has made the integration of connectors higher and higher. Due to the space requirements of automobiles, connectors are also required to have smaller volumes. Occupying a large space, more and more signals are to be received by a single connector. In general, automotive connection systems will develop towards electronic control modules. On the basis of safety and connectivity, miniaturization, intelligence, and integration are the future trends of connector development. The following are some application examples of automotive connectors that meet market needs.

举例 Automotive connector application example

上 At the Shanghai Electronics Fair in Munich, Tyco Electronics brought the latest research and development results-the 050 series terminal and connector system for automobiles. Tyco Electronics' new 050 series terminal connection system has achieved significant technical improvements in miniaturization and weight reduction. Compared with the previous 064 series, it has reduced packaging volume by 70%, reduced weight by 50%, and reduced height by 50%. It is believed that such miniaturized connectors have very important practical value for energy saving and emission reduction of automobiles.

For the safety and miniaturization of automotive connectors, FCI has developed innovative plastic case solutions-APEX-280 and RCS-800 connectors. One of these innovations is a patented interlocking device: ensuring that power is removed as soon as the connector is pulled out-and the unique "two-step" release process provides enough time for the interlocking device to work, so that when power is applied No disconnection will occur. The user does have to perform two separate actions, with a five-second delay between turning off the power and unplugging the connector. These novel safety devices have many other features. After the terminal is fixed in the plastic protective hole, it is prevented from touching by fingers. FCI's ErgoMate gear axial connection system helps to achieve a smaller solution while significantly reducing matching forces. Once mated, the secondary lock of the connector will be closed to ensure a 100% solid connection. In addition, the use of high-level shielding and sealing protection, while achieving a compact and compact design.

In addition, FCI's RCS-800 terminals also meet the needs of automotive connector safety and high connectivity. Its new 8mm round terminal design uses space more efficiently than flat terminals with the same current carrying capacity. These round RCS terminals have many contact points, and according to user requirements specifications, the working current can reach 250A or even higher. In addition, the use of special surface coatings can prevent damage caused by arc discharge. On the other hand, plastic caps provide protection to IP2-x to prevent the danger of electric shock operators.