Rotary motor is the key part of rotary mechanism in full hydraulic excavator. It converts the oil pressure provided by main pump into mechanical energy, which is input to gearbox. At present, the hydraulic rotary motor generally adopts swash plate or swash shaft piston motor with hydraulic brake and mechanical brake inside. The slewing hydraulic brake of excavator is controlled by slewing control valve. When the rotary control valve returns to the neutral position, the rotary motor starts to brake, and the rotary braking torque is set by the buffer valve. However, due to the motor hydraulic braking can not be maintained for a long time, in order to prevent the inclined road from rotating due to gravity, wind and other reasons, in order to make the braking can be reliable for a long time, it is necessary to set up mechanical brakes.
Mechanical brake is composed of brake cylinder, friction plate, separation plate and brake spring. The internal spline of the friction plate is sheathed on the external spline of the cylinder body, and is relatively fixed with the cylinder body, and the teeth of the separation plate are embedded in the tooth groove of the shell. The friction plate and separation plate are alternately stacked together, and the pre compressed spring force of the brake spring is pressed on the housing through the brake cylinder. Friction is produced between the friction plate and the shell, the separator plate and the brake cylinder. Depending on the friction, the drive shaft is limited to ensure long-term and reliable braking when parking.
