Selection of Automotive Wire Terminals and Materials
Definition of Automotive Wire Terminals
The automotive wire terminal is an essential component of the automotive electrical system, responsible for transmitting current, signals, and important data. It plays a crucial role in the normal operation of the vehicle's #electrical system.
With the rapid development of the automotive industry, the importance of #automotive #wireterminals has been well recognized. Therefore, various electrical appliances with different characteristics are emerging in the automotive industry, leading to higher requirements for the electrical performance of automotive wire #terminals. It is therefore imperative that these terminals be of high quality, given their crucial role in the automotive #wiringharness and the vehicle electrical system.
Types of Crimp Terminals
Crimp terminals can be classified into chip terminals, cylindrical terminals, and wire connector terminals.
???The chip series terminals are made of H65Y or H70Y material with a thickness of 0.3~0.5.
???The cylindrical series terminals are made of H65Y or QSN6.5-0.1 material with a thickness of 0.3~0.4.
???The wire #crimp #connector terminals can be categorized into three forms: U-shaped, fork-shaped, and hole-shaped.
Among them, U-shaped terminals are the most commonly used custom terminals, made of H62Y2, H65Y, H68Y, or Qsn6.5-0.1 material with a thickness of 0.4~0.6.
Structure and Functions of Terminals
The automotive wire terminal consists of several parts, including the contact end, wire barrel, insulation cylinder, bell-shaped inlet sleeve, spear hook, truncated piece, and jagged protrusions.
??The contact end is the part that contacts the power supply with the pin holder, while the wire barrel is the part that crimps the conductor.
??The insulation cylinder is the part that fixes the wire's insulation, and the bell-shaped inlet sleeve protects the wire from breakage and surface wear.
??The spear hook is the locking hook when inserted into the shell, while the truncated piece is the residual part after the material tape is cut off.
??The jagged protrusions are the grooves in the wire barrel that ensure good wire contact.
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Material Selection of Terminals
In selecting the appropriate wire terminals, one must consider the material and performance of the terminal. The automotive wire connector end requires stable contact resistance, good mechanical strength and durability, lighter weight, easy processing into smaller sizes, and a certain degree of elasticity.
The following are some of the common materials used for automotive crimp contacts, along with their characteristics:
??Copper (Cu): A yellow alloy of copper and zinc, with 60%~96% copper, is a good elastic material with acceptable electrical conductivity and excellent weldability.
??Brass (CuZn): A red alloy of copper and tin, is a good elastic material, with intermediate elasticity between brass and wrinkled bronze, and has worse electrical conductivity than brass. It is not sensitive to stress corrosion but is more expensive than brass.
??Tin phosphor bronze (CuSn): A yellow material with good elasticity, fatigue strength, corrosion resistance, and wear resistance, but is extremely expensive, about 5 times that of brass.
??Wrinkled bronze (CuBe): A silver-white alloy containing Cu65%, Ni12%, and Zn23%, with electrical conductivity close to brass, corrosion resistance, and strong voltage resistance.
??Copper-nickel-zinc alloy (Cunizn): A gray alloy with an application temperature reaching up to 250 ℃, it has poor electrical conductivity, good elasticity, and wear resistance.
??Steel (Fe): A silver-gray material with an application temperature of up to 650 ℃, it has excellent corrosion resistance, strength, and electrical conductivity.
Coating of Common Wire Terminals
Wire terminals are an essential component of electrical connections in automotive and other industries. Different coatings are used for wire terminals to improve their performance and durability. Here are some common coatings used for wire terminals:?
??Stannum (Sn): Stannum is a silver-white metal that can have a shiny or dark appearance. Tin is softer, cheaper, and easier to solder than other metals used for wire terminals. There are three methods of tinning: pre-tinning, pre-cladding, and electroplating. The thickness of the coating can range from 2μm to 12μm. Brass or bronze tinned with stannum can withstand temperatures up to 110°C, while steel tinned with stannum can withstand temperatures up to 190°C.
??Gold (Au): Gold-plated wire terminals are of the highest quality. Gold is soft, corrosion-resistant, insoluble in pure acid, has good electrical conductivity, and is more expensive than other coatings. Therefore, it is more reasonable to selectively use gold-plating process, that is, only gold-plating on the connecting part. Gold plating usually chooses nickel plating first to achieve a better anti-corrosion effect. The thickness of gold plating is generally 0.4m to 3.5m.
??Palladium (Pd): Palladium is a noble metal with a lower conductivity than gold. It is less commonly used for wire terminals.
??Nickel (Ni): Nickel is a silver-white metal with poor conductivity and a hard and smooth surface. Nickel-plated copper can withstand temperatures up to 340℃, but nickel-plated brass and bronze can only reach 250℃.
??Silver (Ag): Silver is a precious metal that is shiny, white, soft in texture, and has good conductivity. Brass or bronze plated with silver can withstand temperatures of up to 110℃, while copper plated with silver can withstand temperatures of up to 250℃.
Rules for Selecting Auto Wire Terminals
??To ensure safety and reliability in automotive wiring, it is essential to select appropriate wire terminals for different connectors and performance requirements. Here are some specific principles to follow:
??Ensure that the wire terminals are reasonably matched with the selected terminal connectors.
??Select proper terminals according to the diameter of the crimped wire.
??Ensure connection reliability. When selecting terminals, it is necessary to ensure good contact with electrical devices and plug-ins, so as to minimize contact resistance and improve reliability. For example, surface contact is better than point contact, and pinhole type is better than leaf spring type. In the design, it is preferable to use a connector with a double spring compression structure (very small contact resistance)
??Impedance matching. Some signals have impedance matching requirements, especially RF signals, which have stricter impedance matching requirements. When the impedance does not match, it will cause signal reflection, which will affect signal transmission. Therefore, when selecting terminals, it is necessary to select terminals with matching impedance.
Heju Stamping is a precision metal stamping manufacturer with more than 30 years of experience in the industry. We specialize in solving all kinds of complex micro and #miniature-#stampedparts. Please contact us to solve your #metal #stamping project.