Research on Transmission System Noise Caused by Gear Quality


Gansu Metallurgy's research on the transmission system noise caused by the quality of the gums Luo Zhiqing Yu Shutian (Gansu University of Technology Gansu Lanzhou conducted an in-depth discussion, and further proposed several solutions for industrial production and some manufacturers in the processing technology and repair The aspect provides some rumors of gears, as a cell of the machine, which plays an increasingly important role in our daily life as well as in industrial production. In many cases, gears are not only essential but also Product quality plays a key role. For example, car noise and vibration are closely related to the quality of gears in the gearbox. Gears are not presented to us in an individual way. We can only see a huge variety of machine tools. Cars, tractors, electric fans, electric toys, etc. All of this really exists in our lives, and in its unique way, noise affects people's lives. The most used in industrial production is involute cylindrical gears. The involute cylindrical gear has the spur and the helical teeth, such as the gearbox of the machine tool. Most of the gears are helical gears with higher precision grades. In some general shifting systems, such as mixer drives in construction machinery, spur gears are used more. In the stacker drive of automated warehouses, spur gears Both helical gears have been adopted. Studies have shown that when a machine is running in an empty car, most of the noise generated by the gear pair is controlled by the noise, mainly controlling the quality of the gear [2, from the latest gears. From the point of view of "integral error measurement technology", the gear as a series of evaluation parameters of its measurement standard, when used together, must thoroughly understand the overall gear error from the overall perspective, in order to accurately control product quality. The overall error is to treat the error on all working surfaces of the gear as a whole, and the errors of each point on each tooth surface are unified on the meshing line according to the meshing order, forming a gear error set. 1. The transmission caused by the gear quality Problems and solutions are used to illustrate 2 status analysis. There are many problems caused by gear quality. The most important thing is to achieve Its proper motion accuracy, contact accuracy and the resulting noise, such as the gear precision of the machine tool, directly affect the machining accuracy; the excess clearance of the drive system of the stacker causes unnecessary dynamic loads, affecting the accuracy of its positioning, It will affect the normal outbound and warehousing work. For the car engine only, in the medium and heavy-duty vehicles such as the common CA141EQ140, the timing gear pair plays a key role in the valve train. Large oil is also a common type of fault. The oil pump of the lubrication system is a gear pump consisting of a pair of involute spur gears. If the contact accuracy of the gears is not enough, it will affect the oil pressure of the lubrication system, and the oil pressure will be too low. Poor lubrication may cause accidents of burning tiles and pulling shafts. In the differential device of the rear car, it is a conical umbrella-shaped gear. If the matching clearance is improper, abnormal noise will also occur, and the gear will be accelerated. In the years of dealing with cars, the author has successfully analyzed and solved such faults, and studied the reasons. The main reason is the quality of the gears. First, some informal manufacturers. There are many problems in the material and processing technology, resulting in large tooth shape error, poor tooth surface quality and soft teeth. The noise after meshing is inevitable, due to the tooth profile error, installation error and machine tool of the machining tool. The influence of the transmission error will cause the tooth shape error, and the improper matching will also affect the stability of the transmission. [3, 3 Solution First, from the working mechanism of the gear, a pair of meshing gears should achieve stable operation and accurate motion. The three conditions of conjugate must be satisfied: (1) a pair of conjugate points on the mating surfaces of the two gears must coincide at the contact position; (2) the two gears engage the conjugate tooth surface, and must be tangent at the contact point, The entities of the two conjugate surfaces must be staggered to avoid curvature interference; (3) the relative motion velocity of the two-phase conjugate flank at the conjugate contact point must be within the common plane [1], indicating that each tooth has a single tooth The change of the motion error curve is continuous, but the motion of the error curve is discontinuous in most cases when changing from one tooth to another. This feature is reflected as the adjacent two teeth. The overlapping point represents the alternate point of the tooth surface, and the overlapping condition reflects the state in which the tooth surface alternately meshes. It can also be seen that the single tooth motion error curve of the adjacent two teeth has a tangent of different slopes at the same overlapping point, which indicates The alternate point of the tooth surface will produce a sudden change in the speed of the impact, which will generate noise. Therefore, to reduce the noise, the angle between the two tangent lines should be reduced. The overall error theory points out that the transmission quality of the control gear is only controlled. The error maximum of some error items is not enough. It is also necessary to control the change trend of the error (error shape), and often the error shape is more important than the error maximum. The overall error curve can be clearly seen in the middle drum shape. The tooth-shaped tooth change alternates once per tooth, and the tooth surface alternates. The tooth surface of the concave tooth shape alternates three times on each tooth surface, and the primary tooth surface alternates with two impacts. Therefore, even if the maximum error value of the middle drum shape is larger than the maximum error value of the concave shape, the transmission noise is still significantly lower than that of the concave concave shape, so the noise of the gear will be significantly large after excessive wear, and in some new and old gears. When used together, sometimes abnormal sounds may occur. After measuring and modifying the new teeth, the noise reduction effect is very significant. Regarding gear shaping, it is to reduce the impact of a pair of teeth entering and disengaging due to manufacturing errors, gear deformation, etc., and consciously minor trimming of the tooth surface and tooth profile is generally performed. [9. Gear shaping Including the profile modification and the tooth profile modification, including the trimming and root excavation, as shown in the figure profile modification to reduce dynamic load, reduce noise, improve load carrying capacity, improve transmission efficiency, etc. The effect tooth shape modification can be divided into the tooth end thinning drum shape trimming and the spiral angle trimming. As shown in the figure, the tooth end thinning only trims the two ends of the tooth, and the middle is not trimmed, and according to the actual situation, it can be a straight line repair. Thin and curved thinning, tooth end thinning can reduce the load concentration in the direction of the tooth direction, thereby reducing the uneven distribution of the load distribution, and can also form artificial oil culverts, which is conducive to noise reduction. Drum shaping is almost continuous cutting of the full tooth length, which has obvious effects on improving the tooth strength and reducing the meshing noise. The shape of the tooth shape is related to the angle of the "impact error", the amount of load change and the amount of wear 1'] Table 1 The relationship between the shape of the gear and the noise The measured tooth profile error type The tooth noise influence degree Accuracy level Alternate type High speed reload Negative base section deviation Negative pressure angle type Negative base section deviation Positive pressure angle type High precision type drum type Third, the tooth profile of the gear and the influence of the selected pairing noise are also large. Table 1 illustrates the tooth profile of the involute gear and The effect of alternating forms on gear noise The noise intensity is graded according to 5, 4, 3, 2, and 1. The noise of the 5th grade is the strongest. It can be seen that the gear noise is closely related to the tooth profile and gear quality. In the repair of the automobile engine timing gear, comprehensive consideration is given to various errors such as the common normal line and the tooth surface, and various parameters of the old and new gears are matched, and the gears are selected by the gear single-bit gear or the gear overall error measuring instrument. The measurement of transmission error and transmission noise is selected from the best performance pair, so that the selected gear is more effective in improving the engine noise, and in the repair of the gearbox, this method is also very effective. Fourth, with the development of science and technology today, the material industry has provided a wider space for the mechanical transmission. The synchronous belt pulley has replaced the gear transmission to a certain extent. For example, in the car engine timing system, the synchronous belt pulley is generally adopted. The transmission mode has the advantages of accurate transmission, high effect, stable transmission, low vibration absorption noise, no lubrication, convenient maintenance, so it can be used in a wide range. Conclusion The use of gears is different and the requirements are different. The tolerance of the gears is determined according to the requirements of the gears. The overall error theory provides a strong theoretical basis for gear error analysis, gear error repair and noise reduction. The new development of modern industry presents new challenges for gear work, small size, light weight, high transmission torque and high tooth surface. The need for hardness and high precision gears has also become an inevitable trend.

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