In most of the vertical direction load downward pressure structure, due to the inconvenience of linear guide rail installation, the benchmark is not uniform, is not preferred, and the preferred use of three standard parts, the first is linear bearing, belongs to rolling friction guide parts, usually its cage is plastic, load capacity is limited, load requirements are not high, lateral force is basically 0 can be selected.
The second is a sliding oil-free bushing, some inner walls have oil storage grooves, some sides have graphite self-lubrication, this is usually used in small loads, rigid requirements of equipment, because the guide sleeve and guide column clearance is small, and there is no ball to do friction slowdown, nor elastic clearance, life is not too long, but occupy small space, wall thickness is small, flange is short, peripheral space is even more insignificant, generally its accuracy is very high, the gap does not exceed 0.01 mm.
The third is the mold guide sleeve, which is close to the linear bearing, but the ball keeper is independent, the inner and outer rings are separated, with the spring, with the mold movement, the accuracy is higher than the linear bearing, the accuracy of the same grade is worse than the oil-free bushing, about 0.005 mm, and can withstand lateral forces, the bearing capacity is also relatively large.
The guide sleeve used on the mold, whether from the aspect of force or lubrication, the convenience of replacement, load life is impeccable, linear bearings and oil-free bushings, but their replacement after reduction, so we use it cautiously in the design of the later times.
