Multiple ways to reduce gear noise

With the continuous development of industrial technology, the requirements for gear precision are also increasing. After the gear machinery has been explored, it is concluded that there are several reasons for the influence of gear noise:

one. Guarantee the quality of raw materials

Commonly used materials for manufacturing gears are alloy steels such as 40Cr, 20CrMnTi, and 40CrNi, and 45 steel. In order to ensure the quality of raw materials, we adopt the method of fixed-point purchase, that is, to purchase high-quality steel products produced by steel mills such as Shougang, Baosteel and Handan Iron and Steel. After the factory, we must pass strict chemical composition inspection, grain size measurement and The purpose of purity assessment is to facilitate timely adjustment of the heat treatment process, control of heat treatment deformation, and improve the quality of the tooth profile processing.

two. Prevent heat treatment deformation

After roughing or precision forging, the blank shall be subjected to normalizing to eliminate internal residual stress; in normalizing or quenching and tempering, the uniformity of the furnace temperature must be maintained, and the workpiece fixture is used to uniformly heat the workpiece. Cooling; use cyanidation as much as possible, which is lower than carburizing and quenching temperature, less deformation, and cheaper than nitriding or carburizing. For equipment used for cyanidation, it is necessary to use a drop-in type UNIC gas carburizing and nitriding furnace; Some of the high-frequency quenching and cyanidation gear parts can also be changed to a soft nitriding process to obtain high hardness values and thicker white bright layers.

three. Improve the machining accuracy of the tooth blank

1. Improve the machining accuracy of the gear hole: the dimensional accuracy of the gear hole must be distributed around the middle of the deviation of the hole, generally set at ±0.003~±0.005mm, if it is too poor and within the design requirements of the hole , must be transferred to the cutting process separately, in order to take measures; at the same time, the straightness of the hole must be controlled within 0.003mm;

2. Control the end face runout and radial runout of the tooth blank: the end face runout of the tooth blank is a project that directly affects the tolerance of the tooth direction. When machining the two end faces of the tooth blank, it must ensure that the parallelism is within 0.01mm, and then fine on the tooling. Holes to ensure the runout tolerance of the hole to the end face; when cutting the tooth, it is necessary to use the table 100% calibration to ensure the ring runout tolerance of the ring gear.

four. Measures in cutting teeth

1. Gear cutter: 1 All purchased gear cutters must be inspected and must meet the requirements of AA grade. The gear cutters that do not meet the requirements must be fully shovel-grinded; 2 gear cutters are all coated with titanium to improve tool durability. Improve the wear of the tooth top part of the tool and prevent the arc at the root of the gear from being too large; the gear with 3m=0.3~0.8 adopts the top cutting hob; the gear with m=1～2 adopts the top rounding hob, the rounding amount R= 0.1m～0.15m; 4Improve the tooth top interference during gear transmission, increase the tooth top height coefficient and increase (0.05～0.1)m without affecting the gear strength; improve the tool tip durability and avoid gear transmission When the tooth root interferes.

2. Cutting process: 1 The tooth cutting equipment is inspected by the maneuvering station once a year. If the requirements are not met, the radial clearance of the machine tool spindle must be controlled below 0.01mm, and the tool shaft diameter should be less than 0.005mm. The shaft is moved below 0.008mm, the tool diameter jump is controlled below 0.003mm, and the end jump is 0.004mm or less; the gap between the outer diameter of the mandrel and the workpiece hole of the cutting tool must be within 0.001~0.004mm; the thread on the mandrel must be Under the two top positioning, the grinding machine should be ground by thread grinding machine to ensure the verticality ≤0.003mm and the diameter jump ≤0.005mm. The tool tightening nut must ensure that the internal thread and the reference surface are clamped once, and the parallelism of the washer should also be ≤0.003mm; 3The processed gear parts must be evaluated by a full-time inspector, and the test items are Fw, Fr, Fi", fi", Fβ, Ff.

Fives. Processing after heat treatment

1. For the gear hole of soft nitriding and high-frequency quenching of the tooth part, the method of grinding hole before heat treatment and heat treatment is carried out to ensure the processing precision and reduce the production cost;

2. For the cyanide-treated gear holes, all of them adopt the grinding process of indexing circle positioning and Archimedes spiral locking.

six. Adhere to civilized production

According to the data, more than 30% of gear transmission noise comes from burrs and bumps. In order to solve this problem, Gear Machinery Co., Ltd. has taken the following measures: after the gear parts are processed, all of them are transported by the station fixture; after the gear shaft parts are hobbed, the plastic tube is immediately put into the next process, and The plastic casing is shipped; the cyanide-treated gear parts are subjected to liquid blasting and simultaneously honing to remove burrs and improve the surface roughness and processing accuracy of the tooth surface.

Due to the effective measures taken, the military and civil gearboxes produced by the gear machinery were all in compliance with the gear transmission noise indicators at each inspection, which was widely praised by the users. After years of mass production practice, these measures have been proven to be desirable and the results are obvious.