PUMP GP-GEAR 2893530 - Caterpillar

Each travel motor contains a travel brake valve. The travel brake valve consists of counterbalance valve (25) and crossover relief valves (1) and (9) .The travel brake valve is bolted to the travel motor. The travel brake valve prevents the occurrence of a shock load during a travel stop. The travel brake valve also prevents cavitation and overrun. The travel brake valve sends oil to the parking brake in order to release the brake. This occurs before the start of the machine movement.Counterbalance Valve
Level Travel
Illustration 4 g00467949
Travel Motor and Travel Brake Valve (left track) (1) Crossover relief valve (9) Crossover relief valve (12) Port (16) Port (23) Brake valve (25) Counterbalance valve (26) Left travel motorCounterbalance valve (25) consists of valve (6), spring (10), spring (21), check valve (22), and check valve (24) .During forward travel, pump oil flows through port (16), passage (17) and passage (4) to counterbalance valve (25). The oil forces check valve (22) to open. The oil now flows through port (16), passage (17), passage (4), passage (5) and port (14) into the piston of the travel motor. The oil then powers the travel motor.A portion of the pump oil in port (16) flows through passage (15). The oil pushes ball (3) to the left against the force of spring (18). The oil then flows through passage (19) and into spring chamber (20). The oil in spring chamber (20) acts on the left end face of valve (6). Valve (6) shifts to the right side against the force of spring (10).