This model is applied to 13-15T crawler hydraulic excavator, concrete machinery, and all kinds of hydraulic open-circuit equipment. It's displacement is 63x2 (ml/r). Double pumps connected in series, with the controlling method of negative flow control, constant power control,cross power control. Besides, it has the characteristics of high power density, strong self-priming ability, long life and low working noise. It's displacement is 63x2 (ml/r). Double pumps are connected in series, with the controlling method of negative flow control, constant power control, cross power control. Besides, it has the characteristics of high power density, strong self-priming ability, long life and low working noise, etc.