The linear travel valve is next to the left travel control valve core in the four-way directional valve. When the travel and working (or rotary) devices are operated at the same time, the valve connects the travel oil circuits on the left and right sides, the flow supplied to the left and right travel motors is equal, and the motor rotates at the same speed to ensure the linear travel of the excavator. Its working principle is shown in Figure 2-15.
(1) When only walking, because no pilot pressure oil from the shuttle valve of PPC valve flows to the linear walking valve, the walking oil circuits on the left and right sides are closed, and the oil circuits on both sides remain independent.
(2) When the traveling and working (or rotary) devices are operated at the same time, the pilot pressure oil from the traveling shuttle valve pushes the slide valve of the linear traveling valve to the right. At this time, the left traveling oil circuit is connected with the right traveling oil circuit through the groove on the slide valve, and the same pressure oil is supplied to the left and right traveling motors to make the traveling motors on both sides rotate at the same speed, The excavator travels in a straight line.
