UNLOADING RELIEF VALVES BUCG-06/10 (3/4, 1-1/4) Sub-plate Mounting PRESSURE CONTROLS Specifications / Model Number Designation Up to 21 MPa (3050 PSI), 250 L /min (66 U.S.GPM) These valves are used to operate the pumps with minimum load in accumulator circuits or in high-low pump circuits. In accumulator circuits, when the system pressure reaches to a cut out pressure (adjusted maximum), the valve acts to divert the pump delivery to the reservoir at low pressure, thus the pump is unloaded automatically. When the accumulator pressure drops to the cut in pressure (refer to characteristic chart on page 5), the valve directs the pump delivery to the accumulator and hydraulic system. An integral check valve prevents reverse flow through the valve from the accumulator. In high-low pump circuits, the valve acts to unload the large volume pump with the same manner as described above during load operation of the small volume pump. Specifications Model Numbers Approx. Mass Graphic Symbol Model Number Designation FSpecial Seals F: Special Seals for Phosphate Ester Type Fluids (Omit if not required) BUC: Unloading Relief Valve Valve Size Cut-out Pres. Adj. Range MPa (PSI) High Venting Pres. Feature Design Number Design Standards V: For High Venting Pressure Feature (Omit if not required) None: Japanese Std. "JIS" 80: European Design Std. 90: N. American Design Std. Use the high-venting-pressure type to reduce the shift time from unloading to onloading.

Unloading Relief Valves BUCG-06/10 PRESSURE CONTROLS Hydraulic Fluids / Instructions / Others Hydraulic Fluids Fluid Types Any type of hydraulic fluids listed in the table below can be used. Petroleum base oils Synthetic fluids Water containing fluids Use fluids equivalent to ISO VG32 or VG46. Use phosphate ester or polyol ester fluid. When phosphate ester fluid is used, prefix "F-" to the model number because the special seals (fluororubber) are required to be used. Use water-glycol fluid. Note: For use with hydraulic fluids other than those listed above, please consult your Yuken representatives...

Unloading Relief Valves BUCG-06 PRESSURE CONTROLS Model Numbers External Pilot Port "B" Thd. Lock Nut 14(.55) Hex. Pressure Adjustment Handlle Mounting Surface (O-Rings Furnished) Accumulator or System Port 17.5(.69) Dia. Through 26(1.02) C' bore 17.5(.69) Deep Tank Port Pressure Gauge Connection "A" Thd. 17.5(.69) Dia. Through 26(1.02) Dia. Spotface 4 Places DIMENSIONS IN MILLIMETRES (INCHES) 11(.43) Dia. Through 17.5(.69) Dia. Spotface 4 Places 23(.91) Dia. "B" Thd. (From Rear) 3 Places

Unloading Relief Valves BUCG-10 PRESSURE CONTROLS Installation Drawings Model Numbers Drain Port "B" Thd. Fully Extended 154.5 (6.08) 57 (2.24) External Pilot Port "B" Thd. 159 (6.26) 117 (4.61) Lock Nut 14(.55) Hex. Pressure Adjustment Handlle INC. Mounting Surface (O-Rings Furnished) 21.5(.85) Dia. Through 32(1.26) C' bore 21.5(.85) Deep 2 Places Accumulator or System Port 6(.24) Dia. Two Locating Pins Pressure Gauge Connection "A" Thd. Pressure Inlet Port Tank Port 21.5(.85) Dia. Through 32(1.26) Dia. Spotface 4 Places DIMENSIONS IN MILLIMETRES (INCHES) 11(.43) Dia. Through 17.5(.69) Dia....

Unloading Relief Valves BUCG-06/10 PRESSURE CONTROLS Performance Characteristics Hydraulic Fluid: Viscosity 35 mm2/s (164 SSU), Specific Gravity 0.850 Cut-in Pressure vs. Cut-out Pressure Cut-out Pressure Unloading Pressure vs. Flow BUCG-06 High Venting Pressure Feature Unloading Pressure Unloading Pressure Flow Rate High Venting Pressure Feature Flow Rate Pressure Drop for Check Valve BUCG-10 Pressure Drop Pressure Drop Flow Rate

Unloading Relief Valves BUCG-06/10 PRESSURE CONTROLS Spare Parts List BUCG-06-∗∗-30/3080/3090 BUCG-10-∗∗-25/2580/2590 CAUTION When making replacement of seals, please do it carefully after reading through the relevant instructions in the Operator's Manual. List of Seals Part Numbers Note: When ordering the seals, please specify the seal kit number from the table below. List of Seal Kits Model Numbers BUCG-06

PRESSURE SWITCHES ST/SG-02 Threaded Connections/Sub-plate Mounting PRESSURE CONTROLS Up to 35 MPa (5100 PSI) These pressure switches are used in hydraulic systems to make or break an electrical circuit at a preset hydraulic pressure. The pressure switch has two microswitches, each of which is capable of detecting electrically the high pressure or low pressure setting. The microswitch has a dust and drip-proof structure. Specifications Model Numbers Sub-plate Mounting Micro Switch Ratings AC Loads Normally Closed Contact Normally Open Contact Electric Motor, Incandescent Lamp, Electromagnetic...