External displacement sensor apparatus

The utility model relates to an external displacement sensor apparatus which is characterized by comprising a linear bearing, an outer sleeve, a spring, a sliding guide rod, a displacement sensor measuring bar and a shifting sleeve, wherein the displacement sensor measuring bar is disposed inside the sliding guide rod, the sliding guide rod is disposed in the outer sleeve, the sliding guide rod and the outer sleeve are coaxially fixed through bolts, an annular space for placing the linear bearing is arranged between the shifting sleeve and the sliding guide rod, the linear bearing is disposed in the annular space, the spring is fixed on a spring seat in an inner hole of the outer sleeve, a retainer ring is mounted on a left end of the shifting sleeve, the spring seat is disposed between the shifting sleeve and the outer sleeve, the shifting sleeve is provided with a sealing cover disposed on an end part of the outer sleeve, an O-shaped seal ring is disposed between the sealing cover and the outer sleeve, and