Spindle Bearing of Lathe – Adjustment of Radial Clearance and Axial Clearance

2022.9.30

The commonly used processing mechanical equipment in the manufacturing industry is the lathe. However, in the long-term operation process, the wear or deformation of the lathe spindle will increase the error of the lathe or change various clearances, which will interfere with the machining accuracy of the lathe, and even affect its production rate and operation safety. The article will explain the method of adjusting the lathe spindle bearing clearance in detail.

 

Spindle Bearing of Lathe Machine

Spindle is a very important part of the lathe. When turning, the lathe spindle bears a great load. Therefore, when the front and rear bearings supporting the spindle are not adjusted correctly, various defects will occur during processing. If the lathe spindle bearing clearance is too large, the spindle appears axial play and radial runout during turning, which seriously affects the processing quality of the workpiece. On the contrary, if the lathe spindle bearing clearance is too small, the lathe spindle will be damaged due to high-speed rotation.

Therefore, when these abnormal phenomena occur during the lathe processing, the lathe spindle bearing clearance must be adjusted in time. If the lathe spindle bearing clearance is too large, the spindle appears axial play and radial runout during turning, which seriously affects the processing quality of the workpiece. Next, we will introduce the adjustment method of the radial clearance and axial clearance of the lathe spindle bearing in detail.

 

Adjustment of Radial Clearance of Lathe Spindle Bearing

When the lathe is cutting, because the radial clearance of the main bearing is too large, the front bearing clearance is mainly adjusted when adjusting the radial clearance of the spindle bearing. Taking the C620-1 lathe as an example, when the front bearing of the lathe spindle adopts a rolling bearing, the adjustment method for the radial clearance of the spindle bearing is as follows: loosen the supporting screw of the front nut, turn the front nut to the right to make the inner ring of the tapered bearing move along the axis, and then conduct a trial run. If the lathe spindle does not overheat at the highest speed. Under the condition that the supporting screw has no sense of blocking, the spindle can be turned by hand to tighten.

When the front bearing of the main shaft adopts sliding bearing, taking the C620 lathe as an example, the adjustment method of the radial clearance of the main shaft bearing of the lathe is as follows: loosen the jacking screw, rotate the front nut moderately in the constant ring, make the bimetallic bearing move axially, and keep the clearance between the main shaft of the lathe and the bearing between 0.02 and 0.03mm. After adjustment, the lathe needs a trial run. If there is no abnormal operation, the jacking screws can be tightened.

After the above adjustment, control the radial clearance of the lathe spindle bearing within 0.006 to 0.01mm. Inspection steps are also required. Use a dial indicator to measure the radial runout of the spindle centering shaft diameter. If the radial clearance of the lathe spindle bearing is too large, adjust the clearance of the spindle rear bearing and the spindle front bearing.

 

Adjustment of Axial Clearance of Lathe Spindle Bearing

When the lathe is turning, if the lathe spindle bearing has axial movement, the main reason is that the clearance of the rear bearing of the lathe spindle is too large. Therefore, when adjusting the axial clearance of the lathe spindle, the operator mainly adjusts the clearance of the rear bearing of the lathe spindle.

 

The adjustment method for the axial clearance of the lathe spindle bearing is as follows: loosen the rear nut support screw, rotate the rear nut to the right, move the cone rolling bearing inner race along the axis, and reduce the clearance between the lathe spindle shoulder background, thrust ball bearing and rear bearing seat, and then conduct commissioning inspection. If the lathe operation is normal, tighten the support screws.

 

When adjusting the spindle bearing clearance, it is necessary to adapt to the appropriate clearance corresponding to the maximum speed of the lathe, and pay attention to separating the adjustment of each shaft from the engagement shaft to avoid interference. When the lathe spindle bearing clearance is too large or too small, the adjusting screw can be used for adjustment. The axial movement shall be controlled within 0.02mm, and the clearance between the spindle and the bearing can be controlled within 0.01mm.

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