• Categories:News
• Author:David
• Origin:www.kmbearings.com
• Time of issue:2024-06-19
• Views:0

(Summary description)Reducing bearing noise is an urgent problem to be solved in improving bearing quality in bearing industry. The main factor affecting bearing noise is the waviness of bearing groove surface and steel ball surface. Waviness is caused by vibration in the grinding process. Therefore, it is very necessary to study the relationship between vibration and skin texture and the causes of vibration.
Relationship between vibration and waviness
There are many reasons affecting the waviness, which mainly depends on the vibration in the grinding process. The greater the vibration force, the greater the amplitude. With the increase of amplitude, the waviness value of waviness also increases, and the waviness value is directly proportional to the amplitude of vibrating body.
In order to find out the cause of vibration, first measure the number of ripples, and then calculate which kind of vibrating body is. The relationship between them is:
N vibration = an workpiece
Where, n-number of revolutions per minute of vibrating body
N workpiece - revolutions per minute of the workpiece
A - number of corrugations of the workpiece on a circle
Causes and elimination methods of vibration
In the grinding process, the grinder mainly produces forced vibration, self-excited vibration and free vibration. Forced vibration accounts for more than 60%, self-excited vibration accounts for about 30%, and the rest are free vibration.
1. Forced vibration
There are many reasons for forced vibration, but because the vibration frequency caused by forced vibration is often equal to or multiple equal to the frequency of the vibrating body itself, it is easy to find out the vibration source and eliminate it.
1. Caused by unbalanced grinding wheel
(1) The grinding wheel shall be statically balanced once before rough repair, and then statically balanced once after rough repair, and then finish the grinding wheel.
(2) When installing the grinding wheel, pay attention to make the flange of the grinding wheel perpendicular to the conical hole, so that the conical hole and the conical surface of the main shaft are in good contact. The two sides of the sand wheel shall be padded with paper of the same thickness to avoid the imbalance of the grinding wheel due to poor installation.
(3) After the grinding is stopped and the coolant is turned off, the grinding wheel shall continue to idle for 5 ~ 7 minutes, and the special coolant on the grinding wheel shall be removed by centrifugal force. Otherwise, after the machine tool stops for a certain time, most of the coolant will solidify in the lower part of the grinding wheel. When the machine tool is restarted, the grinding wheel will be unbalanced.
(4) Because the internal organization of the grinding wheel is uneven, even if the original balanced grinding wheel will produce new imbalance in the process of use, so it is best to adopt an automatic balancing device in the grinding process.