Vehicle Air Compressor Vibration And Reliability Study

At present, the air compressor used in the middle and heavy vehicle, still mostly used the piston compressor with single cylinder and movement to and fro. This kind of air compressor characteristic is the volume is small, the weight is light, and the cost is lower. But a remarkable shortcoming is the vibration is big. This shortcoming is when engine idling regime revolution, often easy to cause the engine and frame resonating, creates the riding comfortableness to drop greatly.Through the analysis of the influence to the air-compressor vibration by structure design, as well as analyze the dynamics characteristic of air compressor with engine system, research how to reduces the vibration of the air compressor, Enhances the method of improve the air compressor reliabilityThe vehicle air compressor mainly has two kinds of vibration forms: structure vibration and bearing torsional vibration.The structure vibration mainly refers the internal structure in fact has the elastic, example piston, connecting rod, crank, organism and so on, Under gas pressure and moment of inertia function, arouses many kinds of elastic vibration. It is the root of the air compressor operating noise and the vibration rootThe vehicle air compressor bearing and crankshaft rigidity is low, so Can have the torsional vibration in the air compressor work process, simultaneously the automobile power transmission also exists turns inspires. Some engines use the back-end of air compressor crank to output the power to drive to turnaround boost oil pump, injection pump, and so on. The crank receives the extra periodic torque. The torque inspires intensified the air compressor crank fatigue failure.Above two kind of main vibration existence and affects together, may cause the air compressor crank break, connecting rod, piston pin, piston, air pressure case and other components fatigue failure. The air compressor vibration passes the transmission chain to the engine other parts, then possibly cause other part damageIn each kind of failure form of the vehicle air compressor, many reasons that cause failure to be possible to sum up to in the air compressor excessive vibration. The crank endurance failure, the connecting rod break, each bearing premature failure, input valve break, the air compressor body break, air compressor pipeline breakdowns or leakage and so on all related with the air compressor vibration. The research enhances the air compressor the reliability, must consider the influence that each kind of vibration pattern of the air compressor ground-to-air press module fatigue strengththe piston compressor with single cylinder and movement to and fro, decided by its principle of work and the structure, eliminates the vibration is completely not impossible. How to reduce the vibration maximum limit, achieved the redundant reliability is the profession research key.May see by the test curve, on the excitation frequency i.e. the air compressor rotational frequency and the frequency multiplication place. The vibration and the noise value are high. May think the periodic exciting force is a reason that creates vibrates excessively. But at same specification, namely same displacement and working condition, But the different drive type and installs the way to vibrate the scope the influence to be bigBased on the principle to reduce and control vibration, improve designed one kind of modular design air compressor. Improvement principle and main point of design:1. Reduce the weight of the piston link motion gear, optimize design to reduce the weight of the connecting rod, reduce suitably the length of the piston. Use the connecting rod that production by liquid state aluminum alloy dropforging craft to reduce the connecting rod weight greatly.2. Improvement the piston link motion gear stressful condition, Lengthens the connecting rod the center distance, improves the design by 88mm is 94mm.3. Optimized crank transient equilibrium, design reasonability the balance iron construction. Utilizes the special computer software to carry on the examination to the crank intensityMoreover, improve designed other related part of air compressor, including the discharge valve piece, input tube, increase the rigidity that connect with the engine, and so on.Using automobile air compressor overall performance test station, vibration noise test station, using the unit clamp, to measure the vibration and the noise survey of before and after improved product.In view of the fact that at present does not have the direct application experimental standard available, the author has used the analogy experiment method.Through to measure to dynamic torque of the air compressor that before and after improved, we found air compressor torque undulation is smaller than the original structure. It showed that the optimize improvement design of the crank link motion gear, may improve stressful conditions of air compressor crank and other components.Through to measure the air compressor vibration and the noise that before and after improved, we discover air compressor vibrates that improved is smaller than the original structure. It shows to reduce the imbalance force of inertia, may reduce the air compressor complete machine vibration obviously.Through contrast air compressor vibration and noise under different load, we discover that air compressor improved vibrates is smaller than the original structure. It shows to reduce the imbalance force of inertia, may reduce the air compressor complete machine vibration obviously.According to kinds of plan that reduce the vibration to enhance the reliable, has carried on the endurance test, union project practice, it proves that has the effect for enhances the reliability.Carries on the air compressor crank the transient equilibrium design correctly, In under structure permission premise, uses the longer connecting rod, reduce the rotation part imbalance force of inertia. Reasonable match, choose the appropriate air compressor rotational speed scope, Carries on the match experiment, avoid the air compressor and the entire vehicle resonating. When design, avoid using the big stroke the air compressor. Through control the exhaust pressure may control air compressor vibration, then lengthen the air compressor life.During match air compressor and in complete machine, the air compressor designer should communicate fully with the complete machine designer, formulates the main body connection and the attached function structure together. Must guarantee the reliability of the connect structure. Change the air compressor the natural frequency to avoid resonating occurrence. The lubricating oil pipe connection also must enhance the reliability. The lubricating oil pipe reliability regarding the air compressor is fatal, in the lubrication not good situation may cause the air compressor to break the axis, to break the connecting rod, pull cylinder, different sound and so on.In engine factory installing experiment and in actual load use process, must avoid the air compressor revolving in the no-stipulation load. Like spatial load and low load revolution, will reduce the air compressor fact using life. The engine factory engine experiment should pay attention monitors the air compressor the vibration and the noise. The user in the use should guarantee the air compressor works under the normal load, namely guarantee enough braking force, to guarantees the traffic safetyThis article utilizes the vibration analysis method, improves the air compressor design, and enhances the air compressor work reliability. Simultaneously meets the entire vehicle anti-vibration requirements. This research achievement available in similar product design, eliminate the failure causing by the air compressor vibrates.This research, limited by knowledge, experience, time, energy and so on, has not been able more furthers to carry on the basic research in the air compressor vibrate. Hope more people to study this domain, cause our country vehicle to step a new stair with the air compressor profession.