Simplify the problem of noise in the new category of single-body gear area

When the base of the gear drive wheel is smaller than the base of the driven wheel, when the first pair of teeth are still engaged by A1 and A2, the second pair of teeth B1 and B2 begin to engage, but the meshing point deviates from the meshing line, so the flank of B1 is Suddenly hitting the top of B2, the driven wheel suddenly accelerates and rotates, forcing A1 and A2 to detach, and also causing a sudden change in the instantaneous speed ratio, causing impact and high-frequency noise. The effect of tooth profile error. In actual production, it is impossible to obtain a completely correct involute profile due to tooling, machine tool and manufacturing errors. As shown, when a pair of gears mesh, environmental protection and energy saving Page2
The original gears A1 and A2 should be in contact at point a. Because A2 has a tooth shape error, and the contact point deviates to point a, the instantaneous speed ratio suddenly changes, destroying the smoothness of the transmission, generating vibration and low frequency noise. The impact of other major factors on the gear. Abrupt changes in the circumference of individual teeth, burrs, and bruises can cause very annoying noises in gear movements, with low frequency and irregularity. The radial runout of the gear causes the cumulative error of the circumference in one revolution of the gear. Due to the influence of the acceleration, there is a de-toothed meshing impact, no gap on the tooth side or small gap meshing, which causes the gear to interfere and the noise rises sharply. Generally speaking, the tooth surface Low roughness improves noise. In addition, the spoke structure and material matching of the gear have certain influence on noise, which will be discussed in the following measures.
The parallelism, positionality and accuracy of the positioning pin hole of the body gear shaft hole. For the S series wheel train arrangement, there are 6 gears, many gears and more complicated wheel trains. When the parallelism of each hole is out of tolerance, the gear points are contacted, resulting in large high-frequency noise. When the positional degree of each hole changes greatly, some gear meshing gap is too small, and crush noise is generated, and some gear gaps are too large, resulting in "å“—å“—" low frequency noise. Since one end of the starting gear is supported on the body and the other end is supported on the gear chamber cover, the error of the positioning pin hole of the gear chamber and the body will affect the above two aspects of noise at the same time. Moreover, the starting gear simultaneously forms two pairs of friction pairs, affecting three gears. The noise.
The influence of the speed control system The S series single cylinder machine adopts a sliding disc and a flying ball governor. The governor has six steel balls, and the sliding plate is stamped from a thin iron plate and has a large diameter. The high-speed friction between multiple steel balls and the sliding plate itself may generate a lot of noise. In addition, the jump of the sliding plate and its shaft hole can only be controlled at about 0.30, and the size error of the steel ball will cause the steel ball and The sliding plate is unevenly contacted, resulting in a large noise. In addition, the speed control slide has a thin walled "é’¹" shape and has a strong sound field effect, so the speed control system is also the main noise source. The noise meter is used to measure the local noise of the gear room, and the noise at the speed control slide is the largest, indicating that the above analysis is correct.
Factors such as gear lubrication affect the gear noise. The main bearings of the S series single-cylinder machine have double sliding, double rolling, one rolling and one sliding type. For the double rolling model, there is no pressure lubricating oil in the gear chamber, only splash lubrication. The original S machine environmental protection and energy saving design is a seat type, the oil surface is low and the oil gauge has a large range of engraving. Therefore, most of the time when the vehicle is used, the lowest point of the gear can not contact the oil surface, forming a gear dry grinding, resulting in a large noise. Compared with the 1105 gear chamber cover structure, both the S1100 and the 1105 gear chamber cover structure were found to have abnormal noise even in the early stage after the engine was started, although the oil level was high. With the increase of the rotational speed, the sputum oil increases and the abnormal sound gradually decreases, indicating that the gear lubrication has a significant influence on the noise.
Measures to Reduce the Noise of Gear Chambers The machining process of gear precision control gears is generally as follows: the speed control gears are processed by the edging cutters. The other gears use hobbing and then use a standard shaving cutter to shave. Generally, the deviation of the base section fluctuates between ±0.03, the tooth profile error is up to 0.06, and the maximum noise at the gear chamber side is 128dB (A). Tests have shown that the tooth profile error is still between 0.06 without changing the production process, and the gear noise can be reduced by more than 3dB(A) when the baseband deviation is controlled within ±0.011.
Conclusion The noise in the gear chamber is a comprehensive problem and comprehensive measures must be taken. It is impractical to combine production process control and design improvement in order to achieve effective noise reduction. It is unrealistic to emphasize the noise of the gear room by separately emphasizing one aspect. It is worth noting that in many influencing factors and control measures, it is important to control the tooth profile accuracy such as gear base deviation, the coaxiality and position of the main body hole and the positioning pin hole, and make the speed control sliding plate and lubrication. Improvements in the system.

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