NEWS

There are two ways of axial preload for bearings: one is constant pressure preload and the other is positioning preload. Under constant pressure preload, the radial stiffness of the bearing increases slightly as the rotational speed increases, while the axial and angular stiffness decrease rapidly. Under positioning preload, the radial, axial and angular stiffness of the bearing increase rapidly with the increase of rotation speed, but the increase of axial and angular stiffness is relatively gentle.

Dental drill bearings are special bearings for dental handpieces. There is a key component on the dentist's handpiece, called the high-speed dental drill assembly. It consists of a shaft, turbine, spring chuck, spring washer, back cover, shell, rolling bearing, and rubber positioning ring. , the rolling bearing used is called a dental drill bearing.

Pollutants in lubricating oil include various substances mixed in the working medium that are harmful to the surface life of internal combustion engine parts, such as solid particles, water, exhaust gas, diesel (gasoline) oil and polluted energy.

In the surface process, such as grinding a surface on a vertical single-head grinder, the following factors may cause burns if the operating specifications are correctly followed. a. The grinding wheel shaft moves, increasing the instantaneous grinding amount and causing burns; at this time, the grinding wheel shaft bearing must be tightened or the bearing must be replaced. b. The disk on the workbench jumps or rotates unevenly, which increases the amount of instantaneous grinding and causes burns; various components of the disk reducer, such as worm gears, worms, etc., must be inspected and worn parts replaced.

During the grinding process of the bearing ring, due to the cutting, scoring and frictional effects of the abrasive grains on the workpiece, the metal surface is plastically deformed, and the relative displacement between the metal molecules inside the workpiece generates internal friction and heat; when the grinding wheel is cutting, relative to the workpiece The speed is very high, causing severe external friction with the workpiece surface to generate heat. And because the cutting of each abrasive is instantaneous, the heat is generated instantaneously and cannot be dissipated in time, so the instantaneous temperature in the grinding area is relatively high. High, generally reaching 800~1500℃. If the heat dissipation measures are not good, it is easy to cause burns on the surface of the workpiece, that is, secondary quenching and high-temperature tempering will occur on the surface of the workpiece (generally tens of microns to over microns), which will cause damage. The structure on the surface of the workpiece has been removed, and severe burns can be seen with the naked eye. A severe burnt yellow or black oxide film appears on the surface. Minor burns can only be observed after being etched with dilute acidic solution. The burned area will appear black. Burns can reduce the service life of the workpiece.