Repair technology of the hottest high-speed motori

Repair technology of high-speed motorized spindle

three u80 grinding machines were introduced from Sweden to process the middle hole of needle valve body and the seat surface, but it has a great impact on small load measurement. The tolerance of this part requires roundness of 0.5 m and cylindricity of 0 8 m, surface roughness Ra 0.4 M. In order to meet the requirements of high-speed machining, the rotating speed of the motorized spindle should be 100000r/min, the dynamic balance accuracy grade during operation is g0.6, and the rotation accuracy is 0 005mm。 The structure of Swedish high-speed motorized spindle can be divided into three parts: the rotating part composed of stator, rotor and bearing, bearing preloading device and auxiliary device (including electrical interface, oil mist lubrication port and water cooling port). The main shaft can apply preload to the front and rear bearings at the same time, and its size can be adjusted automatically. The advantages are: under the preload, the clearance between the ball and the raceway is eliminated and a certain elastic deformation is formed, so that the bearing has a certain stiffness. For external loads, when the axial force is opposite to the preload, the bearing will not produce clearance, which improves the rotation accuracy of the spindle

3 sets of u80 grinding machines have a total of 12 grinding heads (6 for use and 6 for standby). Under normal circumstances, the replacement cycle of motorized spindle is months. If it depends on import, the annual maintenance cost is 500000-800000 yuan. For this reason, the maintenance personnel of Google once searched every 28 days for a period of time) through repeated exploration, they summarized a set of repair technology of high-speed motorized spindle. The main points are as follows:

1. Measure the static and dynamic radial runout, lifting clearance and axial displacement according to the damage of the motorized spindle

2. Disassemble the electric spindle with a self-made special tool. Clean and measure the rotor runout and wear

3. optional bearing. The consistency error of the inner hole and outer diameter of each group of bearings should be 0.002~0.003mm, which should be 0.004~0.003 mm with the inner hole of the sleeve 008mm clearance; Keep 0.002 with the spindle and send the signal to the computer with a gap of 5~0.005mm. In practice, it is best to use the thumb of both hands to push the bearing into the sleeve. Too tight will cause deformation of the outer ring of the bearing, too high temperature rise of the bearing, and too loose will reduce the stiffness of the grinding head

4. Bearing cleaning is an important link to ensure the normal operation and service life of the bearing. Do not blow the bearing with compressed air, because the hard particles in the compressed air will make the raceway roughened

5. pay attention to the bearing installation direction of conical bearing or angular contact ball bearing, otherwise it will not meet the rotation accuracy requirements. Special tools are used in the whole assembly process to eliminate assembly errors and ensure assembly quality

6. when the inner hole of the sleeve is deformed, the roundness is out of tolerance, or the fit with the bearing is too loose, local electroplating method can be used to compensate and then grind to the requirements, and this method can also be used at the journal

7. The end faces of round nuts, oil seal caps and other parts on the electric spindle are in close contact with the end faces of the inner and outer rings of the bearing respectively, so the perpendicularity of the threaded part and the end face is very high, and the contact can be checked by coloring. If the contact rate is 80%, the end face can be ground to meet the requirements of verticality. This work is very important. Its accuracy will affect the radial runout of the grinder spindle extension rod, thus affecting the surface roughness of the grinding workpiece. China asset management

8. The assembled motorized spindle shall be adjusted axially (measured with a tension spring scale during adjustment), and the static and dynamic radial runout and lifting clearance shall be measured until the assembly process requirements are met

9. Under the actual operating conditions of the machine, excluding the influence of assembly, thermal deformation during machine operation and other factors, the rotor shall be dynamically balanced with a dynamic balancer at a certain speed

using the port layout compound method with the above-mentioned xiu8 Institute, Sanya and Qinglan port as important ports, the axial movement of the grinding head is 0 005mm； On the length of 80mm test bar, the radial runout is 0.010mm