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By 袁春凤 (Tiffany)
China's shortcuts in automobile manufacturing industry
Over the past nine years, China has become the world's largest automobile market and producer, with annual production and sales exceeding 25 million vehicles. China's automotive industry has also been the world's largest automotive industry in just a few years, driven by the huge domestic demand of the Chinese market. But there is not a strong enough component system to support the development of China's automobile industry. In March this year, the 2017 Top 100 list of global auto parts suppliers was officially unveiled. Unsurprisingly, Germany's Bosch Group continued to rank first with more than $46 billion in revenue, while German gearbox supplier Zeiff rose to second. From the third to the tenth ranking of parts companies are Magna, electronics, mainland, Aixin, modern Mobius, Virginia, Lear.
In this ranking, China's highest ranking of parts companies is Yanfeng automotive interior system, followed by CITIC Deka ranked 71. And the selected parts enterprises are mainly single components. Feilong Jiangli supply water pumps for car plants.
In contrast, there is no comprehensive automobile parts supplier in China's automobile industry.
By 袁春凤 (Tiffany)
The phenomenon that two objects move relative to each other to produce motion resistance between their contact surfaces is called friction, which is called friction. The existence of friction not only increases the power consumption, but also causes the wear of parts' contact surfaces. Therefore, lubricating oil is usually used between the relative moving surfaces of automobile parts to reduce friction. Failure of automotive parts 75% is caused by friction.
Friction can be divided into dry friction, liquid friction, boundary friction and mixed friction according to the lubrication state of the parts.
(1) dry friction
The friction between the frictional surfaces without any lubricating medium is called dry friction.
When the parts are in the state of dry friction, the surface of the parts is abraded sharply, so the surface of the moving parts of the automobile should avoid the occurrence of dry friction as far as possible.
Dry friction and boundary friction are the main friction between the upper part of cylinder wall and piston ring. Dry friction will occur when the journal and bearing are subjected to impact load in the working process.
(2) liquid friction
Two the friction of the friction surface when the lubricant is completely separated is called liquid friction.
In liquid friction, the two friction surfaces are completely separated by a layer of lubricating oil film with a thickness of 1.5-2.0um, which avoids direct contact between the working surfaces of the two parts. Friction only occurs between the lubricating fluid molecules, so the friction resistance is very small, and the wear of the parts is very slight.
Most of the relative motion parts of a car are carried out under the condition of liquid friction (for example, crankshaft and bearing).
(3) boundary friction
Two friction surface separated by a very thin boundary film is called boundary friction.
The oil film thickness is usually below 0.1um. Friction only occurs between the outer molecules of the boundary film, reducing the friction and wear of the parts. But its thickness is very small, and it is easy to be destroyed by impact and high temperature, so it is not as reliable as liquid friction.
For example: between cylinder wall and piston ring; if the work crankshaft and journal between the insufficient supply of lubricant, easy to produce boundary friction.
(4) Mixed friction
The friction between two friction surfaces in the presence of dry friction, liquid friction and boundary friction is called mixed friction.
In the actual working state, the parts usually work under the mixed friction state, and the friction state varies with the working conditions.
By Erica Zhu Feilong Jiangli
Automobile parts refer to the components of each unit of the automobile and all consumable materials serving the automobile. They can be divided into automobile parts, Automobile standard parts and automobile materials. The following is a detailed introduction.
（1）Auto parts are divided into parts, assemblies, component, and body panels.
Parts: the basic manufacturing unit of a car. It is an integral part that can no longer be disassembled. Such as: piston ring, piston, valve, impeller and so on.
Assembly: a combination consisting of more than two parts and acting as a single part. For example, a connecting rod with a cover, a pair of bearing shells, and a cylinder head with a valve guide.
Component: a combination consisting of several parts or assemblies, but can not function independently. For example, transmission cover, cooler cover, automobile steering connector, water pump and so on. Sometimes it is also called "half assembly".
Body panels: formed by sheet metal stamping, welding, and covering automotive body parts such as: radiator cover, leaf plate, etc.
(2) automotive standard parts
Designed and manufactured according to the national standards, the same parts are unified in shape, size, tolerance, technical requirements, and can be used in a variety of instruments and equipment, and interchangeable parts are suitable for automotive standard parts such as bolts, gaskets, pins, keys, etc.
(3) automotive materials
Automobile operating materials, such as various oils, solutions, automotive tires, accumulators, standard bearings (non-special), etc.
Most of the products produced by non-automotive industry and used by automobiles, generally not included in the catalogue of various types of automotive accessories, also known as "horizontal products".
By Erica Zhu Feilong Jiangli
Automobile surface drawing parts have the following characteristics:
The deformation characteristics of large curved surface parts are as follows: the periphery is deep drawing, and the interior has bulging components. The surface shape is supplemented by the exterior material of the pressing surface and the interior by the material extension to meet the bulging requirements. At the same time, due to the deep drawing depth and complex shape, the distribution of deformation parts is uneven. Therefore, controlling the direction and velocity of material is extremely important. The part of large curved surface is easy to wrinkle and crack easily.
2.There must be enough stable blank holder force.
Large curved surface parts require not only certain drawing force, but also enough stable blank holder force in the process of drawing. This kind of workpiece is often a large contour size, deep space surface, so the need for deformation and blank holder force are larger. In the ordinary single-action press with air cushion, the blank holder is only about 1/6 of the nominal tonnage, and the blank holder force is not stable, it is difficult to meet the technological requirements of such parts, so in a large number of production, the drawing of such parts are carried out on double-action press. The double-action press has two sliders for drawing and blank-holder, i.e. inner slider and outer slider. The blank-holder force can reach more than 40% - 50% of the total drawing force. It can satisfy the requirement of uneven distribution of deformation around the workpiece, and the blank-holder force is stable, and it is easy to get the deep-drawing parts with better stiffness.
3.The drawing parts must have enough stiffness.
Most of these parts are used as the exterior of the machine, requiring sufficient stiffness (no trembling and noise in use) and dimensional stability (to ensure the quality of welding and assembly). This requires that all parts of the material be subjected to uniform tensile stress (ideally a two-way tensile stress state) in the drawing process, and that the tensile stress exceeds the yield limit, but is lower than the strength limit, so that the elastic recovery of the workpiece is reduced to a minimum, so that the shape is not distorted, but also not rupted.