Patent ID: 9115483
Filing Date: 2015-08-25
Classification: E02F,F15B,G01B,G01D,G01M

Abstract:
1. A hydraulic excavator comprising: a base body portion formed of one of a vehicle main body and a boom; a movable portion supported to be revolvable relative to said base body portion; a hydraulic cylinder supporting said movable portion such that said movable portion is revolvable relative to said base body portion; a position sensor installed on said hydraulic cylinder to measure a stroke length of said hydraulic cylinder; a rotary encoder installed across said base body portion and said movable portion, said rotary encoder including a light emitting unit, a light receiving unit capable of receiving light emitted from said light emitting unit, and a disk unit having a plurality of transmission portions that permit passage of the light emitted from said light emitting unit to said light receiving unit, said disk unit being revolved in synchronization with revolution of said movable portion relative to said base body portion, said light receiving unit outputting, based on the light having passed through said plurality of transmission portions, a pulse signal generated according to an angle of revolution of said disk unit, said angle of revolution of said disk unit being associated with an angle of revolution of said movable portion; and a control unit measuring the stroke length of said hydraulic cylinder by correcting deviation of the stroke length, which is measured by said position sensor, based on said pulse signal output from said rotary encoder.