LASER WELDING OF BEARING PROTECTIVE WASHERS

Spot laser welding was applied for fastening of protective bearing washers.Corresponding technology and laser welding plants are described. Correlation between appearance of the spot welds and their quality was discovered. Mechanism of the welding distortion has been revealed.

NANO-BEARING:THE DESIGN OF A NEW TYPE OF AIR BEARING WITH FLEXURE STRUCTURE

A new type of air bearing with flexure structure is introduced. The new bearing is designed for precision mechanical engineering devices such as mechanical watch movement. The new design uses the flexure structure to provide 3D damping to absorb shocks from all directions. Two designs are presented： one has 12 T-shape slots in the radian direction while the other has 8 spiral slots in the radian direction. Both designs have flexure mountings on the axial directions. Based on the finite element analysis （FEA）, the new bearing can reduce the vibration （displacement） by as much as 8.37% and hence, can better protect the shafts.

Multi-dimensional controllability analysis of precision ball bearing integrity

Many factors affect the integrity of precision ball bearings.In this study,the multi-dimensional controllability of precision ball bearings produced in different company brands(bearing A and bearing B)were studied and compared.The geometric errors(flatness,parallelism,roundness and cylindricity of inner and outer rings,roundness,groove and roughness of inner and outer rings)and vibration errors of bearings were analyzed.Concurrently,the residual stress,residual austenite content,element content ratio,metamorphic layer and temperature-vibration displacement coupling test were also analyzed.Based on the above analysis conclusion,the bearing fatigue life test was carried out for 2150 h.The reliability of the conclusion is proved again as follows.When the residual austenite content in the raceway of precision ball bearing is 10%,the axial residual stress is 877.4 MPa;the tangential residual stress is 488.1 MPa;the carbon content is 6%;the test temperature of bearing is the lowest;and the service life is prolonged.

Precise bearing and automatic target tracking in digital sonar

Precise bearing and Automatic Target Thacking (ATT) for moving vessels is an important thesis in passsive sonar design. Thaditionally in the analogue sonar, DOA (Direction Of Arrival) of the target is determined by the single beam steerillg directioll, which rotate some kind of compensator to steer the target. The compensator is typically made of many electronic and mechanical components. The bearing accuracy substantially depellds on the accuracy of tapped delay line and many mechanical factors. With the application of digital technique in sonar, the precise bearing and ATT technique have attracted much interests for sonar designer. For a digital sonar the multi-beam system has discrete beam direction, which distributed in space, each beam has its fixed steering direction. It is important to use them to estimate precisely DOA of target and then to track the target automatically when the target is moving. An algorithm, which can precisely estimate the value of DOA of the target, is derived in this paper. The relationship among bearing accuracy and the array aperture, signal frequency band is expressed. The expression of time-delay estimation and bearing accuracy is presented. DOA of the target can be precisely calculated by the parabolic interpolation in the neighbourhood of the main lobe of the directivity function. It is easy to implement ATT technique in real time by DSP chips. The results of system simulation show that the algorithm derived in this paper has very good performance in target tracking.