Nagative brake device, construction machine, and method of activating negative

摘要

The present invention includes a hydraulic source ( 23 ), a pressure reducing valve ( 22 ) that reduces hydraulic pressure from the hydraulic source ( 23 ) so as secondary pressure P to become large in accordance with increase in an extent to which a pusher ( 25 ) is pressed in, a negative brake mechanism ( 10 ) that releases braking by secondary pressure P from the pressure-reducing valve ( 22 ) and causes braking to operate in response to cutting of secondary pressure (P), a brake pedal ( 24 ) provided so as to pull out the pusher ( 25 ) according to a depression operation, and a spring member ( 27 ) that pushes in the pusher ( 25 ) so as to release braking performed by the negative brake mechanism ( 10 ) when the brake pedal ( 24 ) is not operated.