Abnormal noise analysis of DF_7 locomotive gearbox


Field experience Exceptional noise analysis of DF7 locomotive gearbox Cui Yuqin, Jie Sidong (Beijing Erqi Locomotive Works, Beijing's main reason for analysis, and proposed corresponding improvement measures DF7 locomotive gearbox with starter gearbox, auxiliary gearbox static Pressure transmission and diesel engine gearbox, etc. Gear transmission will inevitably produce meshing noise, but the meshing impact noise caused by the different backlash size is abnormal. It should be ruled out through several years of practice and it is considered to solve this kind of problem. The problem can only be solved after the gear is assembled, during the running-in test, at different speeds to determine the sound source position of the noise, and then the gearbox unpacking check to solve the gearbox noise causes many reasons, including the gear processing precision, the box The machining accuracy of the hole, the parallelism of the centerline of the hole, the coaxiality of the front and rear holes, the bearing clearance, the deformation during press-fitting, etc., may cause large noise. The following reasons for the noise generation are as follows: (1) Grinding teeth When the root of the tooth is shallow, the root has a step and is arc-shaped, such as when the step exceeds the base circle, then When the mating gears mesh, the top teeth phenomenon will occur, which will cause more noise. For example, the 6mm and z=52 gears of the static pressure transmission 208 and 209 have obvious indentations at the root arc, resulting in paired gears. There is a wear scar on the top of the gear, and the sound is normal after replacing the gear.
There is no problem in the measurement, but after 2~3h of high-speed running-in, obvious indentation appears on the tooth top or root of the tooth of the gear. The measured base section is 0. 008~0.01mm, and the base of the remaining teeth is qualified. In this way, the noise generated by the imbalance is normal, and the sound is normal after the replacement.
This sub-section overshoot phenomenon is caused by the low precision of the gear during machining and the cumulative error of the gear indexing process.
When grinding teeth, noise is caused by changes in pressure angle. Due to the accuracy error of the grinding wheel corrector, the pressure angle changes. When the tooth pressure angle is too large or too small, as long as the tolerance value of the tooth shape is not exceeded, it is still a good product. For gears with 7-step accuracy, the maximum error value of the tooth profile is 0. 016mm, which will be eliminated step by step during the use process, and will not generate large noise. However, during the machining process, due to problems with the wheel modifier, the tooth will be generated. The shape pressure angle is abnormal, resulting in noise.
This is the case with the 6m, z=62 gear of the 946 starter gearbox, which produces noise during the running-in process and the sound is normal after replacement.
Noise generated by excessive meshing clearance. The gear assembly meshing clearance is generally between 0.2 and 0.4 mm. If the meshing gap is 0.3~0.4mm, the noise will be louder, while at 0.2~0.3mm, the noise will be smaller. When the axial turbulence is large, the noise is relatively Also, the center hole tolerance of the larger box hole is ±0.06mm, and the parallelism error is 0.06mm. Therefore, the machining error of the box body is effectively controlled, and the bearing clearance is appropriately adjusted to reduce the gear meshing gap variation and improve the tooth direction. Contact accuracy can effectively reduce noise.
During the handling process, accidental gear injuries can also cause gear transmission noise.
Through the above analysis of gearbox noise, it is not difficult to see that improving gear machining accuracy, strict assembly quality requirements, and avoiding tooth surface damage are extremely important for reducing gearbox noise. After noise occurs, the running-in test should be carefully carried out to find out The cause of the noise.

Plastic Mesh Bags

Plastic Mesh Bags are a popular choice for packaging and transporting a variety of products, including produce, seafood, and firewood. These bags are made from a durable plastic material that is lightweight, breathable, and flexible. Here are some of the key features and benefits of plastic mesh bags:

1. Breathability: The mesh design of these bags allows air to circulate freely, which helps to keep the contents fresh and dry. This is especially important for produce and seafood, which can spoil quickly if they are not properly ventilated.

2. Strength: Plastic mesh bags are strong and durable, which makes them ideal for carrying heavy or bulky items. They can withstand the weight of multiple items without tearing or breaking.

3. Flexibility: The flexible nature of plastic mesh bags makes them easy to handle and store. They can be folded or rolled up when not in use, which saves space and makes them convenient to transport.

4. Visibility: The mesh design of these bags allows the contents to be easily seen, which is useful for identifying products and checking for damage or spoilage.

5. Versatility: Plastic mesh bags can be used for a variety of purposes, including packaging, storage, and transportation. They are suitable for use in a range of industries, from agriculture and fishing to retail and logistics.

6. Cost-effective: Plastic mesh bags are an affordable packaging option, making them a cost-effective choice for businesses and consumers alike.

Plastic Mesh Bags,Red Onion Mesh Bags,Packing Net Mesh Garlic,Onion Potato Mesh Net

Suzhou Yitengjia Extruded Net Packaging Co., Ltd. , https://www.plasticnetbag.com