In recent years, green environmental protection has become the main theme of the development of the automotive industry. At the end of 2016, the Ministry of Environmental Protection officially released the “Light Vehicle Pollutant Emission Limits and Measurement Methods (China’s Sixth Phase)”, requiring that from July 1, 2020, all light vehicles sold and registered should meet the new standards Emission requirements, the market demand for low-VOC products is increasing. In addition, the design of motor vehicles is becoming increasingly lightweight, showing a more compact assembly space, non-metallic materials and finer processing requirements (the width of the flange surface is narrower).

The process of digitization, intelligence, and networking of automobiles has promoted the prosperity of automotive electronic products, while also placing more stringent requirements on the choice of materials. Motor vehicles need to be equipped with more wiring harnesses and sensors, and extreme environments in the car such as vibration and heat will also bring a new test to the service life of electronic products. In addition, consumers pay more attention to the comfort and safety of driving and riding. Humanized design such as vibration reduction and noise reduction, anti-fatigue and jacket design, intelligent car lights are being considered more and more.

These automobile development trends have brought higher requirements for the design and production of automotive parts.

Silicone material has the characteristics of softness, abrasion resistance, expansion and contraction, high temperature resistance, low temperature and so on after vulcanization. Therefore, silicone products have a wide range of applications in industry and daily life. During the application process, we will encounter various problems. The problem is that in the process of product design, the failure to understand the characteristics, elongation and compression rate of silicone rubber, the hardness of silicone rubber, etc., leads to the inability to grasp the size of the silicone seals. Some experience in product production for many years, I would like to encourage everyone.

Silicone Single Wire Seal

Many people may think that it is because the seal is made of silicone material that it will play the role of sealing. In fact, this is not entirely true. It is the silicone single wire seal that really seals it. Performance.

Let’s take a look at its performance, and we know that, in general, its performance includes: stretch, pressure resistance, wear resistance, high temperature resistance, corrosion resistance, elasticity, non-deformation and other properties; and because of these The performance allows the silicone material to be widely used in the application production of seals, and allows other silicone products to have full play.

Perhaps this is a one-sided statement, then you can imagine that in some machinery or equipment that needs to be sealed, the first thing to do is to press the silicone sealed plug, and then squeeze it into the machine to make it fuse with the machine. It can isolate the internal and external air, so it can be fully applied whether it is waterproof or anti-airflow. This is not to be ignored, and it is easy for everyone to see.

Only the comprehensive properties of silicone can achieve the sealing effect. This is the application feature of the connector cavity plug. It has always been one of the products that other materials cannot replace.

From the purpose of the use of automobile connectors, in order to ensure better driving of the car, we can divide the reliability of the connector into the closedness of the connector in use, the performance of the car in fire prevention during driving, and the During driving, the connector can also show shielding performance and temperature control performance.

Generally speaking, when discussing the sealing property of automobile connectors, it is aimed at the sealing performance not only of water in automobiles. In this area, the current popular international management specification is IP67, and this specification is now the highest level in the automotive industry. Although the requirements for waterproofing are different in different parts of the car, many car manufacturers will choose waterproof mating connector seal gasket to ensure the tightness of the connector of their car.

In the driving of a car, the power source is a very important energy source, which is not only related to the normal work of the engine, but also often involves the use of the power source when people are driving. So in the car’s power supply system, car connectors have different divisions, between the male connector and the device, between the male connector and the cable, between the male and female connector, and the female connector. There are certain closing measures between the end connector and the cable that can be implemented.

In the realization of the sealing performance of automotive connectors, the seal ring is a commonly used tool. 36 pin waterproof seal ring can not only achieve the effect of fixing between different hole positions, but also the effect of sealing. It can not only ensure the stable operation of automobile equipment, but also ensure the waterproof performance of automobile equipment in work. In the production of seal rings, silicon rubber is mostly used. This material is made by liquid silicon and solid silicon after certain chemical changes.

Now that automobiles are in use, electronic circuit technology is an important aspect in the automotive industry, not only in driver entertainment, but also in the driver ’s control system while driving. Electronic circuit technology has played an important role in the stable work of automobiles.

In order to ensure that electronic circuit technology can work stably, many shielding technologies are now used in the production of automobiles. These shielding technologies not only play a protective role in the electronic circuit of the car, but also play a role in anti-interference and anti-radiation in the parts of the car. In addition, they can also protect the stable operation of the car connector. These shielding technologies can be divided into two types: internal shielding and external shielding.

Waterproof Seal Ring

When using an external shield to protect a car connector, two identical shield shells are usually assembled to form a shield layer, and the length of the shield layer can cover the entire connector length. It is also necessary to ensure that the shield shell There are enough lock plate structures to ensure the reliable installation of the shielding layer. In addition, the shielding material used must not only be treated by electroplating, but also be treated to prevent chemical corrosion.

The wire harness connector is used to connect the connection points of automobile circuits. It is an important part on the car. Its quality directly affects the power or signal transmission effect. The cost ratio of the connector in the car is small, but if there is a quality problem in the use of the car, it often has serious consequences, and the maintenance cost increases significantly. Therefore, the quality of the connector is more and more obtained by car manufacturers and attention of silicone connector seal supplier.

2 . Terminal mating interference

Terminal mating interference refers to the form of failure of the connector when the male and female ends of the connector are mated, because the male terminal is inserted into the female terminal inactive area, causing the connector to lose its functions such as terminal withdrawal. Generally speaking, the reasons for the interference of terminal insertion are: ① structural design problems; ② terminal insertion and extraction force problems.

2.1 Structural design problems The structural design problems of connectors that involve the interference of terminal mating include: the design of the center distance of the connector (including the wrong size or excessive tolerance), the design of the clearance between the terminal and the sheath (including the clearance Too big or too small) and so on.

2.2 Terminal insertion force

Due to the requirements of assembly performance, the insertion and extraction force of the connector terminal seals should be as small as possible, and an excessively small insertion and withdrawal force will increase the contact resistance of the connector and reduce the conductivity. Therefore, a suitable terminal insertion force is to meet the requirements of the connector assembly performance under the premise of ensuring the electrical performance of the connector. In order to improve the terminal’s electrical conductivity, the insertion and extraction force of the terminal is often increased in practice. Generally, this will cause assembly difficulties. When the terminal insertion and removal force is greater than the holding force of the terminal in the sheath, it may cause the terminal to withdraw during the mating process of the connector.

3. Product application problems

Product application problems involving the withdrawal of automotive connector seal terminals mainly refer to the problems that may cause the terminals to withdraw during the wire harness production process. Generally includes terminal crimping problems and terminal assembly problems. When the degree of excessive bending is light, the insertion and extraction force of the connector is increased, which affects the assembly performance; when the degree of serious bending is caused, the male terminal cannot be inserted into the effective insertion area of the female terminal during the mating process of the connector, and the terminal is withdrawn .

Automotive Connector Seal

4. In conclusion

There are three reasons for the withdrawal of the connector terminal:

① The retention force of the terminal in the sheath is unqualified—generally caused by design reasons, manufacturing reasons, or reasons for using materials;

② Interfering interference — generally caused by design or manufacturing reasons;

③ Product application problems-mainly caused by inappropriate use methods in the product use process.

In actual use, if the terminal withdraws, the cause of the problem should be analyzed first, and the problem should be solved in a targeted manner.

Terminal withdrawal is a more common form of failure for harness connectors. Terminal withdrawal refers to the fact that after the connector is assembled, the terminal is abnormally separated from the sheath, so that the function of the connector is lost. The reasons for the formation of this type of failure generally include three aspects: ①the retaining force of the terminal seals in the sheath is unqualified; ②interference in the insertion; ③product application problems. This article analyzes the terminal withdrawal of the connector and proposes solutions based on these three reasons.

1. Retaining force of the terminal in the jacket is not acceptable

The holding force of the terminal in the sheath refers to the force required to separate the terminal from the sheath in the axial direction. In order to avoid the phenomenon of terminal withdrawal, the performance test standard of the connector strictly stipulates the holding force of the terminal in the sheath: ①the holding force of the connector with a size not greater than 2.8 is greater than 40N; ②The holding force of the connector is greater than 60N. In practice, many terminal withdrawals occur because the holding force does not meet the requirements. In general, the reasons for the failure of the terminal’s retaining force in the sheath are: structural design issues and material selection issues.

1.1 Structural design issues

The structural design problem mainly refers to the design of the connecting structure of the terminal and the sheath. This hook structure is generally an elastic structure, which is divided into an elastic structure on the sheath and an elastic structure on the terminal.

1.1.1 Elastic structure on the sheath

The sheath adopts an elastic structure. The elastic structure required for the assembly of the terminal and the sheath is designed on the sheath. During the assembly of the connector cavity terminal plug and the sheath, a force is applied through the sheath spring (the elastic structure designed on the sheath) Deformation to achieve the assembly of the terminal and the sheath. After the terminal and the sheath are assembled in place, the sheath tongue is restored to its original state due to the release of force. The cooperation of the sheath spring tongue and the hanging structure designed on the terminal ensures the effective positioning of the sheath on the terminal. The shear strength of the sheath tongue determines the retention force of the terminal in the sheath. The design clearance between the terminal and the sheath should be able to ensure that the shear area calculated under extreme conditions can withstand the yield shear stress greater than the required terminal retention force in the sheath.

1.1.2 Flexible structure on terminals

The use of an elastic structure on the terminal refers to designing the elastic structure required for the terminal and sheath assembly on the terminal. During the terminal and sheath assembly process, the terminal spring tongue (the elastic structure designed on the terminal) is deformed by force to achieve Terminal and sheath assembly. After the terminal and the sheath are assembled in place, the terminal spring tongue is restored to its original state due to the release of force. The cooperation of the terminal spring tongue and the hanging structure designed on the sheath guarantees the effective positioning of the terminal by the sheath. The yield strength of the terminal spring tongue determines the retention force of the terminal in the sheath. In practice, it should be ensured that under extreme conditions, the terminal tongue and the hanging platform structure designed on the sheath have a complete cooperation.

Connector Terminal Seal

1.2 Material selection issues

1.2.1 Sheath material selection

Common materials for automotive connector seal jackets are: polyamide (commonly known as nylon), polybutylene terephthalate (PBT), ABS, etc. For the sheath tongue structure, the toughness of the material is generally considered, and the size of the tongue structure is designed according to the allowable yield shear stress of the material that meets the toughness requirements. It should be emphasized that the allowable yield shear stress of the material should be calculated according to the allowable values of the material after the test of high temperature aging, temperature-humidity cycle, and chemical liquid corrosion that the connector may have.

1.2.2 Terminal material selection

Common materials for connector terminals are: copper, brass, bronze. According to their hardness, they can be divided into three states: soft, semi-rigid and hard. Of these three materials, copper is less commonly used, and is generally used for grounded hole or fork joints. Brass and bronze are more commonly used. Brass has better conductivity than bronze, and bronze has better hardness and elasticity than brass. When using the terminal spring tongue structure, bronze should generally be used. The use of brass materials often results in insufficient retention.

As a kind of special material widely used in industries such as industry, electronics and daily necessities, high temperature resistant silicone material is welcomed by customers in the market and refined with high temperature resistant additives.

High temperature resistant silicone material is one of the most important materials in automobile manufacturing. It not only optimizes the automobile manufacturing process, but also improves the performance and safety of the automobile. It has been widely used in various parts of automobiles, such as airbag coating. Layers, power transmission seals, gaskets, hoses, windshield linings, automotive engine seals, ignition wires and coil jackets, automotive turbocharger cooling tubes, sealing and protection of automotive components, high voltage cables and wire harness seals Wait.

Hybrid and pure electric vehicles Compared with traditional fuel vehicles, many high-voltage accessories, such as power batteries, high-voltage power distribution boxes, drive motors, motor controllers, etc., are added, which puts new demands on automotive cables. Because these cables are arranged in the engine area of the front compartment and the chassis area, the temperature is high and the space is small, and the cable needs to be soft, the turning radius is small, and the high and low temperature resistance is good; secondly, the road working condition is complicated, the cable wear resistance must be good and the mechanical strength is high; In addition, the vehicle speed is high and low, especially in severe working conditions such as full load climbing, and the instantaneous high current requires the cable to have short-term overload capability.

Automotive Wire Silicone Seal

In summary, the new energy vehicle custom rubber components such as cable must have: good electrical insulation properties; thermal stability, weather resistance; corrosion resistance, oil and water resistance, excellent flame retardant performance; comprehensive mechanical properties, high flexibility and high tear resistance Split and so on.

At present, automotive power cable insulation materials are crosslinked polyolefins and thermoplastic elastomers. Among them, the crosslinked polyolefin material can be heat resistant up to 150 ° C, but the material of the material is relatively hard, inconvenient to install in a small body space, and requires radiation crosslinking, the process is complicated, and is not suitable for large section cables. The thermoplastic elastomer material does not have a heat resistance of more than 125 ° C, and is used for a low temperature class of the power cable, and the cable of the thermoplastic elastomer material has a risk of cracking for a long time.

The high temperature resistant silicone rubber single wire sealhas high temperature resistance, ozone resistance, weather resistance and excellent electrical insulation; the silicone rubber wire has a large current carrying capacity, saves the conductor cross section, and can cope with the long-time full load operation requirement; the flame retardant can be achieved by adding a flame retardant. Highly flexible, easy to install in a limited space; high tear-resistant silicone rubber, trouser tearing up to 25N/mm. Therefore, silicone rubber materials can make up for their shortcomings while comprehensively crosslinking the advantages of polyolefin and thermoplastic elastomer materials, and silicone rubber can reduce vehicle weight and carbon dioxide emissions, and is a good choice for automotive power cables.

In the production process of wire bundle products, quality exists in all aspects. Therefore, we must ensure that the quality of the finished product is fully inspected to ensure that the shipped goods meet customer requirements and customer satisfaction. However, during this period, non-conforming products will not be avoided in the production process of the wire harness seal, and internal rework is required to re-achieve the products that meet the requirements.

For the assembly assembly, the most common ones are the misalignment of the wiring harness, the damage or poorness of the connector, the bare copper wire of the wire, the misalignment and misalignment of the wire tie, the poor rubberization, and the poor crimping. Select a few for detailed analysis below:

(1) Misplacement.

There are many types of terminals and different shapes. Even if the connectors of the same type are different, it will lead to the development of different rework tools. After the rework, the terminal spurs are not damaged, and when the connector is inserted, a “squeak” sound is heard as good rework. However, in the online beam rework, the gold-plated terminal seals are prohibited from rework, and the safety parts such as antennas, USB, and shielded wires are also prohibited from rework.

(2) The connector is damaged or defective.

There are three types of connectors: no lock, self-locking, and secondary locking. If there are individual defects in the production process, the red label should be placed in the defective magenta box and scrapped. If it is a batch problem, it should be returned to the supplier for screening. First, select a good batch from the warehouse to give priority to use. The reworked connector should have no visible scratches and the lock can be locked normally. Note that the safety parts such as the airbag case cannot be reworked.

Silicone Single Wire Harness

(3) The line is misused or misplaced.

The wire tie is fixed at both ends and the tail is tightened. The presence or absence of test leads and the use of faults can be used for electrical testing or OGC. OGC modules and test modules can be used for error proofing. When reworking the line, pay attention to not scratching the wire and rubber. When re-fixing the wire, the rubber can not cover the functional area, and the tail of the application should be tightened with the corresponding wire gun. Generally, the OGC module can guarantee the positioning. If the wire tie test is used, the full check is used for comparison, and the special slide package is available.

(4) The dimensions do not conform to the drawings.

Silicone wire harness seals are different on the tooling plate, and there is a slight deviation in size. Once the tolerance is exceeded, rework is required. Small branches can be reworked directly online. Once the trunk branch is encountered, most of the glue and wire tie may be required. Therefore, the full inspection is also the last barrier to close the harness.

All rework separation lines and online, regardless of the type, should be reworked by qualified and professionally trained personnel. The rework tools used should be placed in the toolbox and marked accordingly. Rework tools are inspected regularly, even if repairs are replaced. For each reworked wire harness, the rework operation record should be made, including date, production area number, defect cause, quantity, reworker signature, etc., in order to carry out traceability and defect statistics later. For recurring rework reasons, there should be corresponding corrective actions and FMEA/CP/PPM analysis to avoid or reduce such rework.

Rework is just a remedy after a problem. What we need to do is to improve daily and optimize to ensure that good quality is made, not by inspection. To improve customer satisfaction, increase market share; reduce defects, reduce risks and costs; improve products and services as the ultimate goal, thereby accelerating improvement and making the organization sustainable.

Automobile connector is a kind of component that electronic engineering technician often contacts. Its function is very simple: in the circuit is blocked or isolated between the circuit, build a bridge of communication, so that the current flow, the circuit to achieve the intended function. The form and structure of the automobile connector is ever-changing, which is mainly composed of four basic structural components, namely: contact piece, shell (depending on the variety), insulator and accessories. In the industry is usually called sheath, plug, plastic shell and so on.

There are nearly 100 kinds of connectors needed by ordinary cars, and there are about hundreds of connectors used by a single model. As people have higher and higher requirements on safety, environmental protection, comfort and intelligence of automobiles, the application of automobile electronic products is increasing, which will make the application of automobile connectors increase.

The accessories are divided into structural accessories and installation accessories. Structural accessories such as clamping ring, locating key, locating pin, guide pin, connecting ring, cable clamp, sealing ring, sealing gasket, etc. Install accessories such as screws, nuts, screws, spring rings, etc. Most accessories have standard parts and common parts. It is these four basic structural components that enable the car connector to act as a bridge and operate stably.

From the purpose of the use of the car connector, in order to ensure a better car driving, we can divide the reliability of the connector into the sealing performance of the connector in use, the performance of the car’s fireproof flower in driving, in addition, in the driving of the car, the connector can also show the shielding performance and temperature control performance. In general, when discussing the property of automotive connector seal, it is not only about the airtight property of water in automobile.

Automotive Connector Seal

At present, the global automobile connector industry accounts for about 15% of the connector industry, which is expected to take a larger proportion in the future driven by automobile electronic products. In terms of product cost structure, the average connector cost of each vehicle in China is only a few hundred yuan, and the connector cost of each vehicle in foreign countries is about $125 ~ $150, so China’s automobile connector market still has great development potential. In the future, each car will have between 600 and 1,000 electronic connectors, far more than today.

China is expected to become an important manufacturing base for automobile connectors in the future. In addition to the existing well-known international factories, other manufacturers that have not yet set up factories in China will gradually set up production bases in China to supply local auto parts manufacturers due to the increasing local demand, localized procurement, cost advantages and other factors.

Therefore, in the future, China’s automobile connector industry will be a highly competitive market for foreign enterprises and local Chinese enterprises. China will also become one of the important production countries of automobile connectors under the development of foreign enterprises and local enterprises. The future of local enterprises, foreign enterprises, three – funded enterprises who will become China’s car connector hegemony, we wait and see.http://www.kinkongseal.com