How to reduce the noise of ball bearing

How to reduce the noise of ball bearing?

1. Manufacturing process

The refinement of process flow mainly refers to the process flow as short as possible, the combination of process processing and production without intermediate inventory, which effectively reduces the technological factors affecting the performance of low-noise ball bearing; production cleaning and purification, which is a systematic technology, including grinding fluid, ultra semen, cleaning fluid, air, high-pressure air, production environment and other technological processes; automation, from machining to assembly Dynamic, small or unmanned; large-scale, such bearings, especially silent ball bearings, must form a large-scale, in order to have global market competitiveness.

2. Equipment

High speed grinding, electric spindle precision, rigidity, service life and various perfect inspection and maintenance performance play a major role in grinding accuracy and efficiency; grinding machine technology, foreign internal grinder generally have high speed grinding, AC servo control, feed resolution 0.25 μ, full-automatic and easy operation, self diagnosis function, etc.; ultra precision technology, represented by Dongguan shop decoration precision machine There are two ways of ultra precision for the core bearing and four ways of ultra precision for the hydraulic centering represented by the German terenhaus. Since 1980s, the automatic grinding ultra short line controlled by the external feedback of the active measuring machine has been widely used in the Japanese bearing industry. At present, there are about 100 automatic grinding lines in China. With the development of host technology in advanced industrial countries, the connecting line is becoming more and more simple, gradually reducing or not using active measurement and out of machine detection; Centerless cylindrical grinding machine, the outside of the circle (koyomikrosa, etc.) generally adopts the main shaft unit of rolling bearing grinding wheel, which has a series of advantages such as high rigidity, high precision, short life, convenient loading and unloading, reliable use, etc.; the bed has damping attenuation characteristics; and High precision micro motion AC servo system and stable drive AC variable frequency guide wheel adjustment system are adopted, which can be equipped with on-line random intelligent measurement, can realize CBN grinding wheel grinding, etc., and can realize automatic connection, with roundness up to 0.3 μ m and size dispersion up to 3 μ M

Surface grinder, foreign double end (such as koyolan digardner surface grinder spindle are generally used high-precision, high rigidity rolling bearing spindle unit grinding wheel spindle system, oil mist lubrication. Taking Gardner technology as an example, the company has been researching and manufacturing system equipment for more than 90 years, which can grind bearing, ceramics, glass, rubber, plastic and other materials. The main technology of Dongguan Decoration Co., Ltd. is automatic grinding wheel dressing and compensation. The grinding head of the grinding wheel is fed to the coaxial structure of the servo motor lead screw. The grinding wheel is fed to the inside and outside rapidly and synchronously. The feeding accuracy can reach 0.25 μ M. the machine body is placed on two horizontal pads and balancers. The balancer has self balancing supporting rod, which can be automatically adjusted to form a horizontal plane with two horizontal pads, so that the machine tool can be stable The key point of the balancer is to maintain the concentricity of the grinding wheel axis, increase the interval between dressing the grinding wheel. The workpiece can be fed in four forms: rotary, reciprocating, through and special. Super abrasive wheel, diamond wheel and CBN grinding can be used. The grinding accuracy is high, the stability is good, the service life of the grinding wheel is very long and the operation is convenient. It can be specially matched according to the processing requirements The best grinding effect is achieved by making abrasives, binders and structures (ring, button or link). The parallelism and flatness are up to 1 μ M.

At present, the internal structural parameters of deep groove sealed ball bearings in China are almost the same as those of foreign advanced companies, but the vibration and noise level of such products in China is far from that of foreign products, mainly due to the influence of manufacturing and operating conditions. From the perspective of the bearing industry, the working condition factors can put forward reasonable requirements for the main engine to solve, and how to reduce the vibration and noise caused by manufacturing factors is a problem that the bearing industry must solve.

A large number of tests at home and abroad indicate that:

The machining quality of cage, ferrule and ball has different influence on bearing vibration. The machining quality of ball has the most obvious influence on bearing vibration, followed by the machining quality of ferrule. The main influence factors are the roundness, waviness, surface roughness and surface bruise of ball and ferrule.

The most prominent problem of steel ball products in China is that the vibration value is discrete, and the appearance defects are serious (single point, group point, pit, etc.). Although the surface roughness, size, shape and error are not lower than the level outside the circle, the vibration value of the bearing after the sleeve is closed is high, and even abnormal sound occurs. The main problem is that the waviness is not controlled (no standard, no suitable test and analysis instrument) and the anti vibration of the machine tool is explained On the other hand, the management level should be improved to prevent mechanical quality problems such as bump, scratch and burn.

For ferrules:

The most serious influence on bearing vibration is groove waviness and surface roughness. For example, when the roundness of the inner and outer raceways of medium and small deep groove ball bearings is greater than 2 μ m, the bearing vibration will be significantly affected. When the waviness of the inner and outer raceways is greater than 0.7 μ m, the bearing vibration value will increase with the increase of the waviness. The serious gouges can increase the vibration by more than 4dB, or even cause abnormal sound.

Whether it is steel ball or ferrule, the waviness occurs in grinding. Although ultra precision grinding can improve the waviness and reduce the roughness, the most fundamental measure is to reduce the waviness in the process of ultra precision grinding and prevent random knock and bruise

There are two main measures:

1. Reduce the vibration of surface grinding

In order to reduce the vibration, the grinding machine must have good surface machining accuracy and surface texture quality