Hhydraulic rotary transmission constant low speed control device

The utility model discloses a hydraulic transmission and constantly low speed control device, which is composed of a general engine control PLC of principal diesel engine and a hydraulic transmission box which is connected with the principal diesel engine. Characteristically, the hydraulic transmission box is provided with an oil feeding and discharging devices of torque converter. The oil feeding device adopts step control, and the oil discharging device adopts stepless control mode. A constantly low speed electric control cabinet is respectively connected with the general engine control PLC and the hydraulic transmission box. A constantly low speed sensor is connected with the constantly low speed electric control cabinet and the hydraulic transmission box. The constantly low speed electric control cabinet comprises a constantly low speed controller which is connected with an electric motor, a rotation speed sensor and a position sensor. A driving motor rotates and gains feedback signals. Rotating shaft of the electric motor is provided with a gear and an assisting deceleration rack. The deceleration rack is connected with oil feeding and discharging valves of the torque converter through connecting device. The rotation speed sensor and the position sensor are respectively installed on the gear and the rack. The utility model is characterized in high control precison, good stability and convenient reparation.