Introduction: surface grinder dynamic pressure bearing - bearing malfunction analysis and maintenance knowledge

MM7132 flat grinder, the bearing a cone-shaped external cylindrical grinding head and the inner cone bearing hole only three thirds of flange contact, bearing on open 12 axial grooves evenly, bearing axial movement, bearing and shaft radial clearance changes; When bearing tightening only three smaller, the interior of the flange clearance the rest form three oil wedge, elastic deformation for whole three oil wedge pressure sliding bearing. Bearing clearance is small, good rigidity, the lubrication methods for self-priming lubrication. In use process, the grinding head shaft, vibration, heating phenomenon. One, to analyze the causes of the fault through the analysis of the causes of failure in the equipment, found that the surface grinding machine medium sand wheel axle shaft neck part of the surface longitudinal crack, before and after bearing the appearance is no obvious flaw, wear quantity is not big, also to overhaul of grinding head, sand are not found in shaft bending, only have a superficial longitudinal crack in the shaft neck part. Before and after bearing outer cone flange good contact with the bearing holes, the bearing inner hole has no obvious damage. Believed that the main reason of grinding head can't work is: before and after bearing the geometry precision of change, the three oil wedge shape and the size is not consistent. Therefore decided to repair the solution for: repair before and after bearing and hard chromium plating ( 0. 02mm） Repair spindle. 2, scraping and research method of combining the repair bearing by scraping and research method of combining the repair bearing, both the front and rear bearing first scraping and point, then to grind enlarge the contact area and reduce the surface roughness value, scraping by gently scraping the method, can not blow into covered. 1, the front and rear bearing installed to the working position, according to the bearing hole with a 400 mm long cylindrical grinding spindle ( A diameter of 55 mm) And the seriousness with which the grinding will be subject to rotate freely. On the core shaft with a thin layer of red lead oil, wear the spindle bearing, appropriately adjust tightness of before and after bearing, rotating spindle, spare spindle light scratching. The work shall be repeated in order to achieve in article 3 of the before and after the bearing inner surface in rectangular with contact points evenly dense so far. And then polished a diameter smaller than the spindle 0. 02 mm to 400 mm long cast iron grinding rods, which are coated with W5 chrome oxide paste on the front and rear bearing grinding at the same time, always tighten the front and rear bearing and pay attention to remove bearing end redundant abrasives. After grinding, the bearing contact surface to complete three rectangular contact zone, and finally remove the bearing cleaning carefully, make it without any impurities. 2, the front and rear bearing installed, according to the bearing hole with a length of 350 mm cylindrical grinding spindle, cooperation with the bearing inner hole with stiffness can penetrate the advisable. Adjust the before and after bearing until spindle rotation with difficulty. In the process of adjustment, before and after bearing alternates, must not tighten one of the first, then adjust another, according to the core shaft diameter 0. 01 mm size shaft neck, fine grinding spindle assembly after polishing. 3, filling lubricating oil in the empty after loading before the grinding wheel and grinding wheel running test, the grinding experiment was carried out in the end. After grinding, make the front and rear bearing has three width corresponding to its outer cone flange for 15 mm long rectangular interface. In order to further reduce the roughness of bearing inner hole, we try out of toothpaste on the polishing processing. Inspection precision grinding rod final collection found no apparent change, namely diameter minus 0. 01 mm as spindle axis neck size. Three, adopt the method of integating research generation scraping repair bearing 1, turning three 120 mm lead to positive and negative spiral groove cast iron grinding rod overall grinding to ensure the alignment of front and rear bearing. Grinding is the diameter of the rods, before and after bearing fit tighter on the basis of reducing the 0. 02mm. 。 Abrasives used for M28 alumina and kerosene blending. In order to make the front and rear bearing adjustment allowance, as far as possible in the hands of assembly will gently pushing before and after bearing housings, adjusting nut on the belt, then adjust the battery screw tighten. 2, grinding grinding head in vertical state. For convenience of grinding rods do proper axial movement in the process of grinding and reduce labor intensity, the grinding rod directly put a hydraulic jack, through the steel ball bearing grinding rods. To make the holding force in the process of grinding on the installation of the handwheel device in grinding bar top. Four, matters needing attention in the grinding process of grinding rods work direction of rotation and spindle rotating in the same direction. Imbibition oil flow that is conducive to work quickly through the radial clearance form oil wedge, which can improve the operation performance. 1, the grinding process to constantly adjust tight before and after bearing ( Keep a handle) In order to improve the grinding efficiency and ensure the accuracy of the bearing geometry. 2, at any time remove bearing the abrasives in order to avoid excess end of before and after bearing a trumpet. 3, grinding out after a certain time grinding rods, remove the abrasives grinding bar and front and rear bearing, check the effect of grinding and grinding great loss situation, such as grinding bar appear loss, need to repair to ensure the consistency of before and after bearing aperture. 4, when doing the final grinding, abrasive and properly tightened before and after bearing as less as possible to ensure the final geometric accuracy of front and rear bearing. Five, the conclusion of MM7132 flat grinder dynamic pressure bearing repair, assembly, after a successful commissioning, solved the grinding head shaft, vibration, heating phenomenon, can make the equipment normal production safely. We believe that quality is the key to guarantee the before and after bearing alignment, cylindricity and better surface roughness, the three oil wedge shape, size and thickness is consistent as far as possible, and to ensure the quality of the most effective repair technology is on the front and rear bearing on the overall grinding.