Research on Automatic Rod Changing Device of Truck-mounted Rig of Coalbed Methane Based on Electro-hydraulic Control

In order to solve the problems of workers' labor intensity, low efficiency and safety hidden trouble in the process of replacing drill rods for the vehicle drilling rig, an electro-hydraulic control automatic rod changing device is developed. Lifting drill rods to the tray for feeding the fuselage by lifting device, the fuselage and base, clamping, etc. Cooperating with the power head of the vehicle drill to complete the work of loading and unloading drill rods. Aiming at the problem of long centering time and low centering accuracy between the power head and the axis of the drill pipe, which is easy to lead to the damage of the drill pipe thread and sintering, the automatic centering control system of drill pipe and power head is established, and the freedom of front and rear direction of drill pipe and power head is realized. A flexible gripper is designed, which provides three degrees of freedom for the rotation of the drill pipe up-down, left-right, and perpendicular to the axis of the drill pipe. Through the test and application of the prototype, the parameters of the rod changer and the performance of the whole machine are verified. The test results show that: the equipment is suitable for drilling with a diameter range of 89-237mm and a length range of 5-13.8m, automatic loading and unloading of drill pipe reduce the labor intensity, improve efficiency, and realize personnel reduction and guarantee personnel safety.