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ABSTRACT
The article deals with the examination of the state of the ball track of the heavy mining machine ZP6600/Z79. It gives results of material exams which were taken on given samples and describes the progress and results of the numerical computation of the state of tenseness by finite element method of the bottom part of the ball track when it touches the ball.
Keywords: ball track, sample, material exam, state of tenseness, contact tension.
INTRODUCTION
An original idea came from the SD a. s. - Doly Bílina, the idea of a replacement of a ball track at the heavy machine ZP 5500.5 with a ball track from the heavy machine ZP6600/Z79 [3]. This track was already worn, too. The radius of a track groove within the bottom parts of the track and the radius of balls were almost identical. The friction was increasing and pieces of the track material were torn out. The decision about the renovation of the track depended on the determination of the groove degradation level at the ball track. The measuring was made by the employees of the SD a. s. - Doly Bílina in cooperation with VÚHU a.s. Most. The material tests were undertaken on the given samples of the bottom part of the ball track at the heavy machine and a numeric simulation of the tenseness state in the contact area of the ball and the bottom part of the track. The result was an evidence for the decision about the depth of the turned layer of the material in order to create a new track groove of the bottom part of the ball track [1].
The material tests were realized in an external cooperation with the company UNIPETROL RPA s.r.o., a testing laboratory number 1050 accredited by ČIA. The numeric simulation of the tenseness was made in the VUHU a.s. on the 3D model of the contact by a FEM.
The given parameters:
* the bottom part is made from the steel 16 540.8
* the balls are made from the steel GCr15SiMn (G20Mn5; AISI 5210; DIN 100Cr6)
* the total weight of the rotating top of the heavy machine is 1580 tons.
The following figure 1 shows state of the track groove surface at the...