STRUCTURE AND FUNCTION HYDRAULIC PUMP SUCTION SAFETY VALVE 1. Charge pump 2. Charge safety valve 3. Suction safety valve 3A. Valve 3B. Rod 3C. Sleeve 3D. Spring 3E. Spring 3F. Plug 4. Piston pump 5. Travel motor FUNCTION 1) High pressure safety valve The valve restricts the maximum pressure inside the HST circuit in order to protect the HST circuit. 2) Suction safety valve The valve ensures the flow of the charge oil to the closed HST circuit and prevents the charge oil from flowing into the pump high pressure side (delivery side). 10-25 SK714-5 SK815-5 SK815-5 turbo 5 4 2 3 RKS00110 3 1 ety valves installed to 3A 3B 3C 3D 3E 3F RKS00090 each HST pump, and they have the following functions: