Comfortability researc1.doc

Comfortability researchLiquan(Guilin University of Electronic Technology Guangxi Guilin Institute of Electrical and Mechanical Engineering, 541004)Abstract: Comfortability of the car is an important performance, it not only affects the occupant comfort, the work efficiency and physical health, but also directly affect the car of the power, economy and the operation stability, etc, therefore, the auto companies to its focus to the comfortability study will become very important.0. IntroductionCar ride comfort and sex, it is to point to the car in the general speed range road, avoid the car in the course of driving the vibrations and impact, make the person feels uncomfortable, fatigue, and even damage to health, or to make the performance of the damage to the goods. Due to the art of main is according to the comfort of the crew to evaluation, so called ride comfort. Car is a more complicated quality vibration system, the body through the suspension of elastic component and axle connections, and axle and through the elastic tires and road contact, and other such as engine, cabin etc, also be to rubber MATS fixed to the frame. As a result of road gravamen but cause the impact and the acceleration, when slowing down of the inertial force, and the engine and the vibrational excitation from works1.Automobile Ride ResearchBy the power of the bad road, the car allows the speed depends on the ride comfort; forced to reduce traffic speed due to the bad road, and thereby reduce the average car speed, transport decreased productivity. Second, the dynamic load generated by the vibration, accelerated wear of the parts, and even cause damage and reduce the life of the vehicle. In addition, the vibration caused by the consumption of energy to make fuel economy worse. Therefore, to reduce the vibration of the car itself, not only related to passenger comfort and cargo integrity, but also to car transport productivity, fuel economy, longevity and reliability. Of the vehicle ride comfort standards to draw on evaluation criteria established in the vibration, but there are some differences with the international standards.2. The human body to vibration response of the peace of evaluation2.1 car the art of evaluation indexThe art of car of the evaluation method, usually according to the human body to vibration physiology reaction, and to maintain the integrity of the influence of the set, and the physical vibration, such as frequency, amplitude, acceleration as the art of evaluation index.Commonly used in automotive body vibration natural frequencies and vibration acceleration rms value, the evaluation of riding comfort. The tests showed that in order to maintain a car with good ride comfort, body vibration the natural frequency of the body get used to walking on the body, the frequency of the next movement, which is about 60 to 80 times / min (1 a 1.6 Hz) , the limits of the vibration acceleration of 0.2g 0.3g. In order to ensure the integrity of the transport of goods, body vibration acceleration is not too large. If the body acceleration of 1g, there is no fixed goods, it is possible to leave the compartment floor. Therefore, the body vibration acceleration limits should be lower than 0.6g to 0.7g.2.2 the human body to vibration responseIn the 70 s, the international organization for standardization (ISO) in comprehensive extensively about human body vibration of the research work and based on literature review, set the international standard IS02631-1978 E the human body vibration under evaluation guide , so that the whole body vibration in bear evaluation have international generality standards. The standard of mean square root value of with acceleration are 1 80 Hz in vibration frequency range of human body vibration response of the three different feeling boundaries. They were exposed to extreme, fatigue reduce work efficiency boundary and comfortable lower boundaries.2.2.1 Exposure LimitWhen the human body to withstand the vibration intensity in this limit will maintain the health or safety. Usually this limit as a human body can withstand the maximum amount of vibration.2.2.2 fatigue-reduce work efficiency boundaryThis limit and keep on working efficiency. When the driver of the vibration in the bear boundary, can maintain normal on driving.2.2.3 comfort lower boundariesAbout this limit and to maintain a comfortable, it affects people in the car, eating, reading, writing action. The three boundaries is only permissible vibration acceleration values. Exposure limit value of fatigue - reduced to 2 times the efficiency of the boundaries of comfort lower limit of fatigue - reducing the efficiency of the boundaries of 1/3.15. Boundaries to allow the acceleration value is exactly the same trend of variation with frequency.Affect vehicle ride comfort factorsThe previous section we have the car this complex vibration system has been simplified. Will be regarded as linked to each other, the suspended mass and non-suspended mass is composed. The quality of the cars suspension by the body, frame and assembly of the composition. The quality shock absorbers and suspension springs, axles, wheels connected. Wheels, axles constitute a non-suspended mass, the wheels on the road after a certain elasticity and damping of the tire support.Suspension structure, tires, sprung mass and unsprung masses is an important factor in vehicle ride comfort.2.3 suspension structureSuspension structure is mainly refers to the elastic components, orientation device and vibration reduction device, including elastic components and suspension of smooth damping big effect.2.3.1 damping system dampingIn order to attenuation body free vibration and inhibit body, the wheel of resonance, to minimize body vertical vibration acceleration and the amplitude of the wheel, the suspension system should have appropriate damping.In the suspension system, causes the vibration damping source many attenuation. Such as tyre deformation, rubber friction between the molecules, system of shock absorbers, leaf spring leaves the friction between the and so on.Shock absorber damping effect is good, can improve the car ride comfort and sex, improve the wheels and road contact conditions, prevent off road wheels, and can improve the stability of the car, improve the car driving safety. Improve the performance of the shock absorber, to improve the car in the rough road of the speed a huge difference.2.3.2 tiresBecause of their tires elastic, in large part because of the uneven pavement absorbed the vibrations, so it and suspension system to ensure the smooth car.The tyres the performance, it is to use tire in standard air pressure and load, compression coefficient (tires were under pressure of the height and inflatable section of the high percentage) to say. In the maximum allowed under load function, the normal tires compression coefficient is 10% 12%, in order to take comfort, passenger tire compression coefficient older, is 12% 14%.In recent years, with the speed increase, hope the buffer action of tyres more and more good. At present, improve the performance of the tire buffer the method is as follows:increasing section, rim width and tire air capacity, and reduced the tyre pressure2.3.3 sprung massAs mentioned above, the suspended mass distribution coefficient for the evaluation of vehicle ride comfort is extremely important parameters. It depend on the distribution of the suspended mass. The suspension layout of the quality should be 1. 1, the vibration of the suspended mass with each other independently of each other.2.3.4 the suspension qualityReduce the suspension quality, can reduce to vehicle body of impact. The suspension the vibration of the quality, the quality of the hanging vibration acceleration has a significant effect, can make its data value increase. Therefore, in order to improve the car smooth, adopts the suspension quality of smaller independent suspension more beneficial.The suspension of the art of quality, the effects of the commonly used the suspension quality and suspension of quality than evaluation. The smaller proportion of quality, the ride comfortIn short, the influence of the art of structural parameters is a lot, and the relationship between each other is relatively complex, of these parameters to comprehensive analysis, i