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By 袁春凤 (Tiffany)
The most important component of the water pump is the pump shell and the inner parts of bearing and the bearing. To improve the pump, the most important thing is to optimize and improve the two parts. The following is a detailed introduction to the improvement of the two parts.
1. to improve the pump shell. When disassembly the pump to inspect the failure, there are a large number of debris seriously affect the quality of the pump and work efficiency. In this case, we can reduce the two holes used for drainage on the pump shell to one, and remove the drain holes on the upper part of the transmitter. This can greatly reduce the small particles and sundries into the pump, thus greatly reducing the interference of sundries on the pump and the other bad.
2. to improve the bearing. In the case of the failure of the bearing, we are generally sealed, the lubricating oil used by the bearing, the ball of the bearing and the bearing itself. So we should have a solution to these parts
3. to improve gasket. The traditional design is to design the sealing test as a double mouth seal, so the advantage of the design is that two ports are all frictional with the bearing, the roughness of the bearing surface is more appropriate and the wear of the lip is relatively slow; but the disadvantage is that a large amount of dust can be directly entered into the middle of the mouth and bearing, so that the plate will be used for a period of time. The interference between the bearing and the bearing decreases, thus losing the original function of the seal. There are two ways to improve it: the first is the sealing week of the bearing with double, and the sealing area is lengthened properly and the thickness of the chip mouth is thickened accordingly. The method is to change the original double mouth into the three form of the seal and seal the seal. The advantage of this structure is that the outer lip and mouth have increased the seal design, which can resist many dust. However, this method also has shortcomings, the mouth and the reverse cap friction, the surface roughness of the surface of the cover is relatively poor, it is very easy to wear and tear seal test, resulting in sealing failure.
4. to improve the lubricating oil. The bearing of the automobile pump is a more special bearing unit. Its environment is mostly temperature, humidity and dust, and the temperature of the water usually reaches about one thousand degrees, so the lubricating oil of the bearing is required. From our analysis of the fault, the lubricating oil in the bearing of the fault appears discolourable, which means that the grease in the lubricating oil is not enough, so the lubricating oil manufacturer should be required to increase the fat content of the lubricating oil so as to ensure the better protection of the bearing.
5. to Improve the contact ball of the bearing. Balls in bearing are important parts to ensure normal operation of bearings, but there are more and more damage to rolling balls. When measuring the hardness of the ball, it is found that most of the balls do not meet the required hardness requirements, which makes the bearings greatly wear at high speed and finally breaks down completely. Therefore, we should strictly supervise the production quality of the manufacturers, guarantee the hardness of the ball and pass the quality, so that the fundamental problem of bearing damage can be effectively solved.
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 袁春凤 (Tiffany)
Melt mold casting
One is to make the wax into a mold, coat it with several layers of refractory paint to make a mold shell, and then heat the mold, so that the mold melt, flow out, and baked into a certain strength mold, and then poured, shell and get a casting method. Process features: take the melting pattern as the starting mode. The precision of casting is high, and it is a method of little cutting. Its equipment is simple and production quantity is not restricted. It is mainly used for mass production and mass production. The drawback is that the process is complex and the production cycle is long.
Pressure casting - a casting process in which molten metal is rapidly pressed into the cavity of a metal mold under high pressure and solidified under pressure to obtain a casting. Process characteristics: High speed and high pressure were added to the metal mold casting to enhance the metal fluidity, which was mainly used in the batch production of non-ferrous alloy (such as aluminum, copper, magnesium, etc.) precision castings.
Centrifugal casting - a casting process in which molten metal is poured into a high-speed rotating mold to solidify liquid metal under centrifugal force to obtain a casting. Process features: compact structure, good casting quality. It is used to produce hollow castings.
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 袁春凤 (Tiffany)
Fatigue life prediction of rubber bushing in vehicle system
1.Response analysis of rubber bushing under random excitation The Monte Carlo method is used to simulate the random excitation spectrum.
2. The fatigue life calculation of rubber bushing under random load can calculate the maximum strain energy density of rubber bushing under different excitation by using the response characteristics of rubber bushing under engine and road excitation obtained previously. The fatigue life of rubber bushing can be calculated under different load conditions. The maximum strain energy density U = 0.5134Nmm2 and the fatigue life N = 771371 were predicted under the excitation of engine speed n = 3000r/min and class B pavement, while U = 0.6893Nmm2, N, = 146774 under the excitation of engine speed n = 3000/min and class D pavement.(Thanks for the help and support of Chongqing Feilong Jiangli Auto Parts technical department.)
3. The test verification of the front sub-frame module is expensive because of the fatigue test of the whole vehicle system. Now the former sub-frame module is the research object, and the calculation results are compared with the test results. The front sub-frame is installed in accordance with its layout in the vehicle, and the six points connected with the body on the sub-frame are restrained. Sinusoidal excitation is carried out at the midpoint of the rear beam, and the maximum frequency which can be reached under the condition of satisfying the amplitude of the force is taken as the test frequency. The amplitude of force is 2.45.2kN. Fatigue failure criteria of rubber bushing: 2mm crack (equivalent to 20% of tensile coefficient).