The working principle of timing valve in TB1140 hydraulic excavator is as follows:
TB1140 hydraulic excavator timing valve function prevents the hydraulic excavator parking brake when the motor stops suddenly.
When the parking brake moves, the pressure oil flowing from the orifice P4 always flows to the hole PG, and the spool valve (1) is pushed to the right by the spring (2) force, and the orifice PG is closed.
When the rotary pilot pressure or the rod leading pressure is directed to the hole SH, the spool valve (1) is moved to the left side and is resistant to the spring (2) force, and the orifice PG is opened.
The pressure oil flowing out of the orifice PG is introduced into the central hole of the slide valve (1), and the parking brake release hole (PB) is introduced to release the parking brake.
When the pilot pressure at SH of the orifice is disappearing, the spool valve (1) is moved by the force of the spring (2) to the right side, and the orifice PG is closed, thereby preventing the oil escaping in the brake piston cavity (3).
The oil in the chamber gradually flows through the throttle (1) throttle (4) and out of the outlet Dr, so the parking brake does not move quickly, but it takes a certain time, as if the timer is used to delay.
