How To Eliminate CNC Machine Tool Gear Noise

How to eliminate CNC machine tool gear noise

Gear noise of CNC machine tools is caused by many factors together, some of which are determined by the gear design parameters. For the characteristics of the gear noise of the spindle motion system appearing in the faulty milling machine, the noise can be reduced by trimming on the original gear without changing the original design.

1, Tooth top trimming the edge

    Due to the influence of tooth shape error and tooth pitch, after the elastic deformation of the gear teeth bearing, it causes transient jacking and impact during gear meshing. Therefore, in order to reduce the meshing impact caused by the concave and convex top of the gears during meshing, the top of the gears can be resharpened. The purpose of top edge trimming is to correct the tooth bending deformation and compensate for the gear error, so as to reduce gear noise. The amount of edge repair depends on the tooth pitch error and the amount of bending deformation of the gear after bearing, as well as the bending direction. Repair the edge of the machine mainly for the highest frequency of meshing of those pairs of gears and these gears in the modulus of 3 to 5 mm when taking the different repair edge amount.

    In the edge of the repair must pay attention to the edge of the control, and take repeated testing methods, so as not to repair the edge of too large and destroy the effective work of the tooth profile, or repair the edge of too small to play a role in repairing the edge. Tooth shape repair edge, according to the specific situation of these pairs of gears only repair the top of the tooth or only repair the root, only when the top of the tooth alone or repair the root can not achieve good results, the top of the tooth and the root of the tooth to jointly repair the edge of the radial and axial values can be allocated to a gear, can also be allocated to two gears according to the situation.

2, Control tooth shape error

    Tooth shape error is caused by a variety of factors. Observing the gears in the transmission system of the faulty milling machine, it is found that the tooth shape error mainly occurs during the machining process, and secondly, it is caused by poor long-term operating conditions. Tooth shape error is more common in the noise that occurs when the gears mesh. In general, the greater the tooth shape error, the greater the noise that appears. For the concave tooth shape, the gear teeth are impacted twice in one mesh, and the noise is very large, and the more concave the tooth shape, the greater the noise. Therefore, the gear teeth will be reshaped to make it appropriate in the convex shape, in order to achieve the purpose of reducing noise.

Control the change of the center distance of the meshing gear

    If the center distance of the meshing gear changes periodically, the pressure angle will also change periodically and the noise will increase periodically. The analysis of the meshing center distance shows that the noise effect is not obvious when the center distance is large, while the noise increases significantly when the center distance is small. When controlling the center distance of the meshing gear, the outer diameter of the gear, the deformation of the drive shaft, and the fit of the drive shaft with the gear and bearing should be controlled in the ideal state. This will eliminate as much noise as possible due to the change in the center distance of the mesh.

3, Pay attention to the role of lubricating oil for noise control

    Lubricating oil plays a certain role in damping while lubricating and cooling, and the noise becomes smaller with the increase of oil volume and viscosity. If a certain thickness of oil film can be maintained on the tooth surface, it can prevent direct contact between the meshed tooth surfaces, which can attenuate vibration energy and thus reduce noise, so it is beneficial to reduce noise with oil of high viscosity. The main drive system of the faulty milling machine uses splash lubrication, and the splash lubrication will increase the oil disturbance noise.

    The actual gear lubrication requires very little oil, and its main purpose is to form a pressure oil film to facilitate lubrication. Experiments have proven that gear lubrication is best when oil is given to the meshing side. This practice allows the lubricant to act as both a cooling agent and to form an oil film on the tooth surface before entering the meshing area. The noise reduction effect is even better if a small amount of splashed oil can be controlled to enter the meshing area. Accordingly, each oil pipe is rearranged so that the lubricating oil is splashed into each pair of gears according to the ideal condition to control the noise generated due to unfavorable lubrication.

    Gear trimming and good lubrication can effectively suppress noise generation. Before operation and use, we should adjust the position of CNC milling machine gears, lubricate well and avoid gear damage.