KobelcoDynamic Acera Kobelco Construction Machinery America LLC Control Valve Kobelco Construction Machinery America LLC. Dynamic Acera 01/2002 Page 7-1 CONTROL VALVE 7-2 Main control valve (SK210 • SK290) 1. Appearance & specifications Travel Right Travel Straight Bucket Travel Left Boom P1by-pass cut (Top) & Arm Conflux (bottom) Swing Boom Conflux Arm ArmV/R (top) Swing & Priority P2 by-pass cut (bottom) Negative Control (Pn) PN2 Pressure relief valve Note: ORV ············ Over load relief valve MRV ············ Main relief valve AVR ············· Arm variable recirculation Dynamic Acera 01/2002 Page 7-2 4 +/.3 (348 psi) at 30 L/min (7.9gpm) Over load relief valve Other three placed : 37.3 (348 psi) at 30 L/min (7.0.5 (5757 psi) at 40 L/min (10.4 +/.5 (0.7 +/.5 (5757 psi) at 30 l/min (7.9 gpm) Spool Stroke mm (in) Cut Recirculation 8.9 gpm) Pilot Pressure (Max) Mpa (psi) 2.413 in) Dynamic Acera 01/2002 Page 7-3 .334 in) other 10.0.0.4 +/.5 (0.3 (348 psi) at 30 L/min (7.7 +/.5 gpm) Set pressure of 2.0.7 (5467 psi) SK210 210 x 2 (55 gpm) SK250 238 X2 (62 gpm) Max flow rate L/min (gpm) SK290 238 X 2 (62 gpm) SK330 235 X 2 (62 gpm) Boom H Bucket H Arm R: Set pressure of Mpa (psi) 39.9 gpm) Mpa (psi) Neg-Con relief valve 2.0. CONTROL VALVE Item Specifications Model KMX15YB Max pressure Mpa (psi) 37. MINOR CHANGE MAIN CONTROL VALVE Travel Right Travel Straight Bucket Travel Left Boom P1 by-pass cut (Top) & Arm Conflux (bottom) Swing Boom Conflux Auxiliary Valve Arm Activation Port Circuit Relief Low Flow Port ArmV/R (top) & Auxiliary Port P2 by-pass cut (bottom) (STD. Blank) Front of Machine Typical of SK210 SK250-6E Minor Change Dynamic Acera 01/2002 Page 7-4 . MINOR CHANGE MAIN CONTROL VALVE Front of Machine AVR Arm Variable Regen (top) Option Valve Activation Port Arm P1 By-Pass Cut (Top) Boom Holding Valve Boom Conflux Boom Bucket Swing Travel Right Travel Left Main Relief Travel Straight Typical of MINOR CHANGE SK210 SK250 Dynamic Acera 01/2002 Page 7-5 . Main control valve (SK480) Arm-1 Boom-2 Option-1 ARM-2 Swing Boom-1 Travel Bucket Travel Left Travel Straight Main Relief Valve Toshiba Dynamic Acera 01/2002 Page 7-6 . 9 gal/min) Swing 26. Arm H 34.7 (4550 psi) Mpa (psi) When power boost pressure 34. Item Specifications Part No.2 (460 psi) 50L/min (13 gal/min) Dynamic Acera 01/2002 Page 7-7 . Arm R 36.9 gal/min) Mpa (psi) Boom R.4 (3840 psi) at 30L/min (7.9 gal/min) Foot relief valve set pressure Mpa (psi) 3. LS30V00002F1 Model Mpa (psi) UY36-105 Rated flow L/min (gpm) 370 X2 (98 X 2) Main relief valve set pressure 31.3 (4980 psi) Over load relief valve set pressure Boom H. Bucket H.8 (5050 psi) at 30L/min (7.2 (5260 psi) at 30L/min (7. Bucket R. Block of P1 side 2. Cross-sectional view 1. Block of P2 side Dynamic Acera 01/2002 Page 7-8 . CONTROL VALVE 2. Travel right section Swing section Dynamic Acera 01/2002 Page 7-9 . CONTROL VALVE 3. Travel straight section Travel left section 4. work spools for swing. CONTROL VALVE NEUTRAL Neutral P1 pump delivers oil through P1 port of main control valve. arm and through P2 neutral cut spool. bucket. Pn2 port delivers oil to Pn2 port at pump regulator keeping P2 pump at minimum flow. Oil flows through travel priority. P2 Pump is regulated by the low pressure relief valve. P2 pump delivers oil to P2 port of main control valve. Pressurized oil from P2 Pump is regulated by the low pressure relief valve. Dynamic Acera 01/2002 Page 7-10 . boom and P1 neutral cut spool. Pn1 port delivers oil to Pn1 port at pump regulator keeping P1 pump at minimum flow. Pressurized oil from P1 Pump is regulated by the low pressure relief valve. Oil flows to travel priority valve were the oil flow is stopped. work spools for travel right. and to travel left spool. AL FOR. Ab RAI ARM CONFLUENCE PCb Pis P1 NUTRAL CUT P2 NUTRAL CUT ARM VARIABLE RECIRCULATION PCa PA1 CCa Pn2 Pn1 Pn1' 3.7MPa 37. PAL FOR.14MPa Pn2' at 35L at 35L Tn2 Tn1 (P3) SE28 PBo1 P PAo1 30 37. BOOM PLc1 PAb RAI PAa DIG. Bb LOW.7MPa at 30L CRa at 30L at 30L 39. Aa DIG. Drb LCs SG PBS RIG.7MPa at 30L 37. AS Br REV.7MPa CCb at30L PLc2 DIG.7MPa AO1 at 30L BO1 (P4) Dynamic Acera 01/2002 Page 7-11 . TRAVEL PRIORITY TRAVEL LEFT CT2 CP2 BL REV. Drc LCa ARM PBa DIS. CP1 (T3) Dra BOOM CONFLUENCE LCc PBc DIG.14MPa 3.7MPa PAc DIS at30L Bc DIG Ac DIS 37. PBr REV.7MPa CRb 37. PAS LEF. CT1 SWING PAr FOR. CONTROL VALVE S/V P2 P1 T CMR1 PL1 MR1 CMR2 PTb PBL REV. Drd LCb PBb LOW. BUCKET 39. Ar FOR. TRAVEL RIGHT BS RIG.7MPa at30L Ba DIS. 39. LEF. P2 Pump is regulated by the P2 neutral cut spool. CONTROL VALVE NEUTRAL MINOR CHANGE Neutral P1 pump delivers oil through P1 port of main control valve. functional spools for travel right. Pressurized oil from P1 Pump is regulated by the P1 neutral cut spool. Dynamic Acera 01/2002 Page 7-12 . Pressurized oil from P2 Pump is regulated by the low pressure relief valve. bucket. boom and P1 neutral cut spool. arm and through P2 neutral cut spool. Oil flows through travel priority. work spools for swing. The PSV (Proportional Solenoid Valves) at the pump regulator keeps P1 pump at minimum flow until the C-1 main computer activates the pump. P2 pump delivers oil to P2 port of main control valve. and to travel left spool. Oil flows to travel priority valve were the oil flow is stopped. The PSV (Proportional Solenoid Valves) at the pump regulator keeps P2 pump at minimum flow until the C-1 main computer activates the pump. 4 ¯ 0.4 Pis ARM VARIABLE P2 NUTRAL CUT RECIRCULATION PCa CCa TB PBo2 (P4) PAo2 Ao2 50 Bo2 (P3) Dynamic Acera 01/2002 Page 7-13 .8 PB1 CCb PLc2 Drd LCb LCa PBa ARM PAa Pisc CRb Aa CRa CAr Ba X1 ¯ 3.4 ¯ 0. CONTROL VALVE NEUTRAL MINOR CHANGE P2 P1 T T2 CMR1 MR1 CMR2 PBL TRAVEL LEFT PAL AL STRAIGHT TRAVEL CT2 CP2 BL LCs PBs TRAVEL RIGHT PBs2 SWING Pss CT1 P ¯ 1.4 PAs As Bs CP1 (T3) LCc BOOM CONFLUENCE ¯ 0.5 ARM CONFLUENCE ¯ 0. 5. P2 pump delivers oil through P2 port of main control valve. b. a. The amount of current is determined from information given to the CPU from low pressure sensor (SE3). to low pressure relief valve and Pn1 port keeping P1 pump at minimum flow. The PSV-B secondary pilot oil acts on the neutral cut spool port PCa located on the bottom of the P2 section of the main control valve block. neutral cut spool. Oil flows through work spools travel left. P1 pump. CONTROL VALVE BOOM CIRCUIT UP Neutral P1 pump delivers oil through P1 port of main control valve. Secondary pilot oil from operators joystick has shifted boom confluence spool allowing oil from main control valve P2 to join with control valve P1at one way check valve CCb. With the boom confluence valve shifted a one way check valve allows oil from P2 section of the control valve to join with the oil from the P1 Section of the control valve through CCb load check. Oil flow from P1 pump opens load check valve (21) CP1. and the boom conflux spool. arm and neutral cut to low pressure relief valve and Pn2 port keeping P2 pump at minimum flow. Secondary pilot oil from the operators joystick enters port PB1 of the boom conflux spool located on the P2 section of main control valve and moves the boom conflux spool (7) down. work spools for bucket and boom. Boom raise operation (Conflux circuit) 1. a. P1 pump oil reaches boom spool (8) through LCb load check valve (21). downstream of travel right spool. With P2 Neutral cut spool closed by the PSV-B solenoid valve oil is removed from low pressure relief and Pn2 port. a. The CPU outputs a command current (milliampere) to P2 neutral cut proportional solenoid valve (PSV-B) located on the solenoid proportional valve block. Pump 2 is not on. 3. Pilot oil acts upon the P2 neutral cut spool and moves P2 cut spool closed. Dynamic Acera 01/2002 Page 7-14 . flows into parallel circuit (P4) and closes CT1 check valve. P1 oil flow is diverted from work spools. out port Ab of main control valve to boom cylinder piston side. Secondary pilot oil from the operators joystick acts on boom spool. and flow from P2 pump is directed to parallel port P3. 2. b. Secondary pilot oil from the operators joystick enters port PAb of the boom spool located on the top of the P1 section of the main control valve pushing the boom spool down. d. a. 4. With boom spool (8) shifted. b. 6. neutral cut spool. P2 pump is now considered on line. Oil flow from P2 pump opens Cp2 load check valve located below travel left spool. P1 pump is now considered on line. c. The pressure oil from P1 pump passes through and around boom spool (8). low pressure relief and Pn1 port. arm and boom confluence spool. swing. Oil flows through travel straight. Oil flow from P2 pump is now availabel for work spools swing. 7MPa CCb at30L PLc2 DIG. AL FOR. BOOM PLc1 PAb RAI PAa DIG.7MPa PAc DIS at30L Bc DIG Ac DIS 37.7MPa at30L Ba DIS. Drb LCs SG PBS RIG. Bb LOW.14MPa Pn2' at 35L at 35L Tn2 Tn1 (P3) SE28 PBo1 P PAo1 30 37. Ab RAI ARM CONFLUENCE PCb Pis P1 NUTRAL CUT P2 NUTRAL CUT ARM VARIABLE RECIRCULATION PCa PA1 CCa Pn2 Pn1 Pn1' 3. PAS LEF.7MPa at 30L 37. PBr REV.14MPa 3. Aa DIG. CP1 (T3) Dra BOOM CONFLUENCE LCc PBc DIG. AS Br REV. CT1 SWING PAr FOR. 39. TRAVEL RIGHT BS RIG.7MPa 37. CONTROL VALVE BOOM CIRCUIT UP S/V P2 P1 T CMR1 PL1 MR1 CMR2 PTb PBL REV. Drc LCa ARM PBa DIS.7MPa AO1 at 30L BO1 (P4) Dynamic Acera 01/2002 Page 7-15 . LEF.7MPa at 30L CRa at 30L at 30L 39. TRAVEL PRIORITY TRAVEL LEFT CT2 CP2 BL REV. BUCKET 39. PAL FOR.7MPa CRb 37. Drd LCb PBb LOW. Ar FOR. flows into parallel circuit (P4) and closes CT1 check valve. 2. the holding pressure on the boom cylinder head side acts on it and moves rightward. 4. Oil flows through work spools travel left. b. A part of the return oil flow from boom cylinder head end flows into recirculation chamber in the boom spool (8). spring chamber (J) of boom lock valve (17) is connected to drain port (Drc) through passage (SB). neutral cut spool. a. 6. Port PBb is located on the bottom of main control valve P1 section. a. and the continuity between passages (Sa) and (Sb) is cut. which directs the oil to the rod end of the boom cyliner to prevent cylinder cavation. arm and neutral cut to low pressure relief valve and Pn2 port keeping P2 pump at minimum flow. downstream of travel right spool. P1 pump oil reaches boom spool (8) through LCb load check valve (21). The boom lock selector valve spool (23) is moved to the right. Since boom lock valve (17) is connected to drain port (Drc). Orifice (H) of bushing (79) is connected to drain port (Drc). and boom lock port PLc1 of the boom lock selector valve (19). low pressure relief and Pn1 port. work spools for bucket and boom. 3. to low pressure relief valve and Pn1 port keeping P1 pump at minimum flow. P2 pump delivers oil through P2 port of main control valve. CONTROL VALVE BOOM CIRCUIT DOWN Neutral P1 pump delivers oil through P1 port of main control valve. With the movement of spool (23). P1 oil flow is diverted from work spools. return oil from the boom cylinder head flows through main control valve Ab port to boom spool. 5. b. With boom spool (8) shifted. the orifice G of bushing (79) closes. a. The remaining oil flows into the tank or return oil circuit. b. P1 pump. The holding pressure from the boom cylinder head side stops acting on spring chamber (J) of boom lock valve (17). P1 pump is now considered on line. out port Bb of main control valve to boom cylinder rod side. Secondary pilot oil from operators joystick acts on the boom spool (8) moving spool up. Oil flow from P1 pump opens load check valve (21) CP1. Secondary pilot oil from joystick enters boom spool port PBb. With boom lock valve (17) CRb port open. The pressure oil from P1 pump passes through and around boom spool (8). Boom lower operation (Recirculation circuit) 1. Dynamic Acera 01/2002 Page 7-16 . releasing the boom lock poppet (17). neutral cut spool. and releases the locking. Oil flows through travel straight. swing. Operation of boom lock valve (CRb) 1. CONTROL VALVE BOOM CIRCUIT DOWN Dynamic Acera 01/2002 Page 7-17 . Oil flows through travel straight. Secondary pilot oil from joystick enters boom spool port PAa. P2 pump oil is stopped at CT2 one way check valve closing valve oil can not enter P1 port of main control valve. c. swing. c. CPU activates straight travel spool. brake is released. to low pressure relief valve and Pn1 port keeping P1 pump at minimum flow. P2 pump delivers oil through P2 port of main control valve. The arm spool is located in the P2 section of the main control valve. CPU supplies 24 volts of power to swing parking brake solenoid SV-1. The CPU outputs a command current. With the arm spool shifted oil is removed from low pressure relief and Pn2 port. a. The arm variable recirculation spool is in the full stroke condition after the engine starts and is in the forced recirculation condition pilot pressure at PSV-A is 25 kg/cm2 (355 psi). Power from CPU to swing parking brake solenoid (SV-1) is removed swing parking brake is released. d. a. b. Swing parking brake is released by the mechatro controller from low pressure sensor (SE7). Oil flows through work spools travel left. d. Dynamic Acera 01/2002 Page 7-18 . The PSV-C proportional valve secondary pressure acts on Pis arm variable recirculation spool (13) starts returning from the full stroke to the regular recirculation condition. P2 pump delivers oil through P2 port of main control valve. The arm variable recirculation proportional valve (PSV-A) located on the solenoid proportional valve block through the mechatro controller from low pressure sensor (SE7). port PLc2 is on the bottom of main control valve P2. b. Port PBb is located on the top of main control valve P2 section. P2 pump is now considered on line. 4. releasing the arm lock poppet (17) 2. swing. and boom lock port PLc2 of the arm lock selector valve (19). blocking pilot oil to Swing parking brake. Oil flows through work spools travel left. arm and neutral cut to low pressure relief valve and Pn2 port keeping P2 pump at minimum flow. Secondary pilot oil from operators joystick acts on the arm spool pushing the arm spool down. neutral cut spool. CPU releases power to swing parking brake. b. The arm lock selector valve spool (23) is moved to the right. With arm spool shifted P2 oil flow from P2 pump is stopped at the arm spool and diverted to CP2 load check valve located below travel left spool opening valve. The PSV-A proportional valve secondary pressure acts on Pis arm variable recirculation spool (13) starts returning from the full stroke to the regular recirculation condition. Arm-in operation (Normal recirculation) 1. work spools for bucket and boom. a. arm and neutral cut to low pressure relief valve and Pn2 port keeping P2 pump at minimum flow. straight travel soool is shifted. brake is on. CONTROL VALVE ARM CIRCUIT IN Neutral P1 pump delivers oil through P1 port of main control valve.Pro 3. P2 pump flow is now in the P3 parallel port and available for swing circuit boom confluence circuit and arm circuit. After the oil passes around arm spool oil is diverted to the arm variable recirculation valve. CONTROL VALVE ARM CIRCUIT IN 5. 2. Oil is restricted from retuning to hydraulic tank and is allowed to help P2 oil feeding piston end of arm Dynamic Acera 01/2002 Page 7-19 . Return oil from Rod end is restricted for regeneration and return to Hydraulic tank. 1. to arm spool. b. c. 6. Return oil is ou restricted and allowed to return to hydraulic tank. Return oil from arm cylinder passes over arm holding valve which is in release condition. cylinder (arm regeneration) 3. P2 pump flow reaches arm spool through LCa one way check valve. Return oil form arm cylinder rod side is delevered to P2 main control valve port Ba. The arm recirculation valve will then make a determination from infromation from the CPU controller as to the three paths for the return oil to take.Oil flow from P2 flow travels around arm spool out Aa port located in P2 main control valve to arm cylinder piston side. a. 4. Secondary pilot oil from joystick enters arm confluence spool port PA1pushing the spool up located in the P1 section of the main control valve. work spools for bucket and boom. Oil is restricted from retuning to hydraulic tank and is allowed to help P2 oil feeding piston end of arm cylinder (arm regeneration) 3. 1. P2 pump flow is now in the P3 parallel port and available for swing circuit boom confluence circuit and arm circuit. c. Arm-out operation (two pump flow) 1. arm and neutral cut to low pressure relief valve and Pn2 port keeping P2 pump at minimum flow. neutral cut spool. The CPU outputs a command current into P1 bypass circuit (PSV-D) located on the solenoid proportional valve block through the mechatro controller from low pressure sensor (SE-8). With arm spool shifted P2 oil flow from P2 pump is stopped at the arm spool and diverted to CP2 load check valve located below travel left spool opening valve. to arm spool. Secondary pilot oil from operators joystick acts on the arm spool pushing the arm spool up. Secondary pilot oil from joystick enters arm spool port PBa spool located in the P2 section of the main control valve. d. pushing arm confluence spool up. P2 pump oil is stopped at CT2 one way check valve closing valve oil can not enter P1 port of main control valve.Oil flow from P2 flow travels around arm spool out Aa port located in P2 main control valve to arm cylinder piston side. P2 pump delivers oil through P2 port of main control valve. The arm recirculation valve will then make a determination from infromation from the CPU controller as to the three paths for the return oil to take. Return oil is ou restricted and allowed to return to hydraulic tank. Oil flows through work spools travel left. Oil flows through work spools travel left. 3. CONTROL VALVE ARM CIRCUIT OUT Neutral P1 pump delivers oil through P1 port of main control valve. Dynamic Acera 01/2002 Page 7-20 . and arm confluence spool. Oil flows through travel straight. Return oil from arm cylinder passes over arm holding valve which is in release condition. a. swing. arm and neutral cut to low pressure relief valve and Pn2 port keeping P2 pump at minimum flow. With the arm spool shifted oil is removed from low pressure relief and Pn2 port. Return oil form arm cylinder rod side is delevered to P2 main control valve port Ba. 2. to low pressure relief valve and Pn1 port keeping P1 pump at minimum flow. Swing Parking brake applied. a. swing. P2 pump delivers oil through P2 port of main control valve. b. P2 pump flow reaches arm spool through LCa one way check valve. After the oil passes around arm spool oil is diverted to the arm variable recirculation valve. P2 pump is now considered on line. a. 2. b. Return oil from Rod end is restricted for regeneration and return to Hydraulic tank. c. c. P1 Neutral cut is shifted by CPU. b. The arm variable recirculation spool is in the full stroke condition after the engine starts and is in the forced recirculation condition pilot pressure at PSV-A is 25 kg/cm2 (355 psi). 7MPa VB LEFT TRAVEL REVERSE at 30L Ba DIS.4 Pis P1 NUTRAL CUT P2 NUTRAL CUT ARM VARIABLE RECIRCULATION PCa PA1 CCa Ø0.4 Ø1.6 Ab RAI X1 Ø3.4 ARM CONFLUENCE Ø0.H. RIGHT TRAVEL FORWARD 39. 27 SWING 147kPa 490kPa Drb LCs PB DB 21 SG B 15 PBS RIG.0 T R. 5 A1 Pi1 Ø1.4 BOOM RAISING 26 BOOM LOWERING SWING LEFT A1 A2 A3 A4 A5 A6 A7 A8 SWING RIGHT LOCK ATT P2 P1 ARM VARIABLE TRAVEL SWING A1 TRAVEL ARM DIGGING 25 NEUTRAL PRIORITY NEUTRAL RECIRCULATION 1/2SPEED P/B LEVER BOOSTING CUT CHANGEOVER ARM DISCHARGE T CUT P 16 T.9 MPa PBr REV.H.0 24 P1 TRAVEL INDEPENDENT S/V P2 P1 BUCKET T T2 55 gpm 8 CMR1 2 a3 a4 M PL1 MR1 CMR2 1 10.0 ARM cc/rev 135 Hp @ 2000rpm PTb PBL REV. M PG PB1 PA BUCKET 39.4 Ø0. AS Br REV.7 MPa CONTROL VALVE ARM CIRCUIT OUT AO1 at 30L 37. 17 18 LEF.7 MPa CCb at 30L PLc2 DIG. Dr A2 BOOM Pi2 12 Ø1.8 C TRAVEL Bc DIG PILOT VALVE P T 13 Ac DIS 37.7 MPa CRa at 30L VA at 30L LEFT TRAVEL FORWARD 39. TRAVEL PRIORITY TRAVEL LEFT 20 CT2 19 CP2 BL REV.3 Pcr35.3 D PBb LOW.2 BUCKET DISCHARGE Ø1.7 MPa PAc DIS at 30L Ø0.6 Ø0. TRAVEL A Drc LCa ARM PBa DIS. Aa DIG.14MPa 3. D Drd MB B LCb LEFT Ø0. 3 AL FOR.7X4 F E BOOM&BUCKET Pn1 Pn2 D ARM&SWING T P T P PILOT VALVE B P PILOT VALVE Pn1' 3. a5 7 Dr B1 B3 Dr3 A3 PAL FOR. Ar FOR. 4 14 ACC 3 6 4 1 5 2 Bb LOW.3 MPa C Ø1.14 MPa Pn2' MA Pcr35.0 4 SE8 SE7 SE6 SE5 SE4 SE3 SE2 SE1 RIGHT Ø0.3 MB D TRAVEL BUCKET DIGGING Ø1.6 PAo1 1 3 2 4 3 1 4 2 30 VB Ø0. TRAVEL RIGHT BS RIG. Ø0.7 MPa 37. PAS LEF.H.3 MPa R.7X4 A Ø1. 10 10 (P3) SE28 PBo1 P Ø0.8 MA P 37. Ø14-Ø12.6 37.8 27. at180L CT1 SWING PAr FOR.3 37.S T P1 P2 Page 7-21 .4 9 PCb Ø0.5 Ø0. SE26 SE22 SE23 P P P a5 PSV1 a1 A1 A2 a2 PSV2 a6 PH1 PH2 SE27 P1 P2 P a8 a9 TRAVEL BOOM PN2 T INDEPENDENT Dynamic Acera 01/2002 P PN1 23 VALVE P2 6 L.H. BOOM 11 PLc1 PAb RAI PAa DIG.7 MPa at 30L VA BO1 (P4) 22 P P P P P P P P Ø1. Tn1 Tn2 L.8 at 35L at 35L Ø0. CP1 (T3) Dra BOOM CONFLUENCE LCc P A PBc DIG.7 MPa P SE10 P SE9 at 30L RIGHT TRAVEL REVERSE CRb 37. to low pressure relief valve and Pn1 port keeping P1 pump at minimum flow. a. Flow and pressure in circuit is proportional the movement of joystick effecting SE-1 sensor. Bucket digging operation single pump flow (voltage at SE-1 less than 2. a. P1 pump oil flow reaches bucket spool through LCc check valve.5 volts) 1. Secondary pilot oil form joystick enters boom spool port PBc. low pressure relief valve and Pn1 port. b. P1 neutral cut spool. 5. P1 pump is now considered on line. The pressure oil from P1 pump passes around bucket spool. 2. P2 pump delivers oil through P2 port of main control valve. bucket spool is moved upward. Dynamic Acera 01/2002 Page 7-22 . CONTROL VALVE BUCKET CIRCUIT DIG Neutral P1 pump delivers oil through P1 port of main control valve. Oil flows through travel straight. swing. out port Bc of main control valve to bucket cylinder piston end. With the bucket spool shifted P1 oil flow is diverted from the boom work spool. Oil flows through work spools travel left. Oil flow from P1 opens load check valve CP1 downstream of travel right spool. Secondary pilot oil from the operators joystick acts on bucket spool moving the bucket spool up. Return oil from rod end of bucket cylinder is deleverd to bucket spool through Ac port located in the P1 section of main control valve. 3. neutral cut spool. work spools for bucket and boom. 4. P1 pump oil flow in to parallel circuit (P4) and closes CT1 check valve. arm and neutral cut to low pressure relief valve and Pn2 port keeping P2 pump at minimum flow. Port PBc is located on the bottom of main control valve P1 Section. b. 0 D MA P 24 IND.2 LEVER ATT P2 TRAVEL P1 ARM TRAVEL SWING 25 T LOCK BOOSTING BY-PASS STRAIGHT BY-PASS VARIABLE 2-SPEED P/B A1 P CUT CUT RECIRCULATION CHANGEOVER TS 16 T SV-4 SV-2 PSV-B PSV-C PSV-D PSV-A SV-3 SV-1 P1 P2 SK210/SK250(LC)-VI BUCKET DIGGING (Two pump flow) WITH POWER BOOST Page 7-23 .7X4 ¯1.7MPa P SE10 P SE9 at30L RIGHT TRAVEL FORWARD A UP PAb PAa IN PA PG LEFT TRAVEL REVERSE LEFT TRAVEL FORWARD Aa IN LOW Bb at30L CRb 39.14MPa 3.7MPa A DUMP Ac at30L 13 ACC B CCb PLc2 IN D 11 LCb Drd 6 5 DOWN PBb at30L 4 3 2 1 RIGHT TRAVEL REVERSE Drc BOOM 37.7MPa CRa 37. MB TRAVEL D MOTOR(RH) SE26 4 SE22 P P P SE23 PSV-P1 (a5) (a1) A1A2 (a2) (a6) PSV-P2 INDEPENDENT TRAVEL VB SE27 P T 23 VALVE 18 PSV-1 PSV-2 PH1 PH2 Dynamic Acera 01/2002 P1 P2 VA (a8) P Dr (a9) A2 P12 9 ¯1. TRAVEL SOL. P1 F B E ~6Kg/cm 2 ~6Kg/cm 2 C A P2 P1 T T2 MA P (a3) (a4) CMR1 M 2 1 PL1 CMR2 (a7) PTb MR1 TRAVEL LEFT PBL REVERSE Dr B1 B3 Dr3 A3 TRAVEL PRIORITY PAL FORWARD CT2 AL FORWARD VA CP2 19 20 147KPa BL REVERSE VB 490KPa Drb TRAVEL RIGHT ¯14.7MPa PLc1 at30L ARM & SWING T P BOOM & BUCKET T P UP Ab Ba OUT PILOT VALVE PILOT VALVE X1 ¯3.7MPa LCa ARM PBa OUT 39.4 8 SE6 P SWING RH ¯1.8 21 27 REV PBr CT1 LCs FOR PAr PBS RH 4TRAVEL 15 CP1 SWING PAS LH REV Br MOTOR(LH) MB D 17 AS LH FOR Ar LCc BS RH DIG PBc P (T3) SWING Dra BUCKET DUMP PAc 39.14MPa Pn2' BOOM SL SR AK AR BK BR B BA H R (Tn1) at35L at35L H Tn2 22 ¯1.0 PN1 PN2 T A1 P11 ¯1.7MPa 30 BUCKET SE3 at30L P BOOM UP (A01) 37. ¯1.5 ARM CONFLUX ARM PCb Pis H 10 10 P1 BY-PASS CUT P2 BY-PASS CUT ARM VARIABLE RECIRCULATION PCa R PA1 CCa 7 5 6 8 7 1 2 4 3 ¯1.7X4 23 (Pn1) (Pn2) Pn1' 3.0-12.7MPa R at30L (P4) H SE4 (B01) P BOOM DOWN P SE5 SWING LH 24 ¯1.8 PILOT VALVE P T 37.7MPa C BOOM at30L PB M DB TRAVEL 14 DIG Bc CONFLUX B 3 PB1 ¯0.4 SE7 P ARM IN SE8 P ARM OUT SWING PRIORITY A1 A2 A3 A4 A5 A6 A7 A8 SOL.0 (P3) 6 (LH) S SC AC BC BD BL AD BH SE28 (PBo1) P 12 SE1 (PAo1) P BUCKET DIGGING H (OPTIONAL) R 5 (RH) SE2 CONTROL VALVE BUCKET CIRCUIT DIG P BUCKET DUMP 37. Pilot oil acts upon the P2 neutral cut spool and moves P2 cut spool closed. bucket spool is moved upward. a. a. low pressure relief valve and Pn1 port. The amount of current is determined from information given to the CPU from low pressure sensor (SE-1). Bucket digging operation two pump flow (voltage at SE-1 greater than 2. The PSV-B secondary pilot oil acts on the neutral cut spool port PCa located on the bottom of the P2 section of the main control valve block. With the bucket spool shifted P1 oil flow is diverted from the boom work spool. arm and neutral cut to low pressure relief valve and Pn2 port keeping P2 pump at minimum flow. work spools for bucket and boom. CONTROL VALVE BUCKET DIG TWO PUMP FLOW Neutral P1 pump delivers oil through P1 port of main control valve. b. neutral cut spool. Oil flows through travel straight. Port PBc is located on the bottom of main control valve P1 Section. Flow and pressure in circuit is proportional the movement of joystick effecting SE-1 sensor. P1 neutral cut spool. The CPU outputs a command current (milliampere) to P2 neutral cut proportional solenoid valve (PSV-B) and the travel priority proportional solenoid valve (PSV-C). a. 2. P1 pump is now considered on line. Oil flow from P1 opens load check valve CP1 downstream of travel right spool. b. b. Dynamic Acera 01/2002 Page 7-24 .5 volts) 1. c. swing. P1 pump oil flow reaches bucket spool through LCc check valve. P2 pump delivers oil through P2 port of main control valve. Pilot oil acts upon the travel priority spool and moves the travel priority spool closed. to low pressure relief valve and Pn1 port keeping P1 pump at minimum flow. Secondary pilot oil from the operators joystick acts on bucket spool moving the bucket spool up. Secondary pilot oil form joystick enters boom spool port PBc. The PSV-C secondary pilot oil acts on the travel priority spool port PTa located on the top of the P1 section of the main control valve block. P1 pump oil flow in to parallel circuit (P4) and closes CT1 check valve. Oil flows through work spools travel left. 3. c. P2 pump oil now enters P1 main control valve center section. Oil from P1 pump is directed through CT2 one way check valve and enters P3 gallery located in the P2 section of the main control valve. stopping the P1 pump oil from entering the center section of P2 main control valve. and flows to cooler and tank. b. Oil from P1 pump enters P4 parallel gallery through CT1 one way check valve. with no passage to oil cooler of hydraulic tank. a. P1 pump oil enters the main control valve P1 section. P2 pump oil enters P2 main control valve center section. 1. P1 pump oil closes one way check valve CP2. b. and flows to cooler and tank. a. P2 pump oil enters the P1 section of the main control valve and is directed by the travel priority valve. Dynamic Acera 01/2002 Page 7-25 . with no passage to oil cooler or hydraulic tank. 2. oil flows through travel priority spool and is directed away from the center section of P1 main control valve. CONTROL VALVE TRAVEL PRIORITY SPOOL ACTIVE Travel Priority Spool Active (shifted) With the travel spool active oil flow from P2 and P1 pump is redirected. moving respective spool. P2 cut spool (12) is switched in proportion to the pilot secondary pressure. 10. but it comes to a stop. the pressure oil opens load check valve (21) CP1 on the donwstream of travel right section and flows into parallel circuit (51) on P1 side. and flows into bucket spool (5) through U-shaped passage. and travel straight spool (1) is switched. On the other hand. the pilot secondary pressure acts on PBc port on the bucket section of block on P1 side and moves bucket spool (5) upward. Because bucket spool (5) on the bucket section of is moved. and finally by-pass circuits (50. On the other hand. but not confluxed in the combined operation. For the bucket dumping operation. 2. 6. 8. and fed into the bucket cylinder head side through C/V BC port and bucket digging circuit (60). the delivery oil opens load check valve (21) CT2 on the block on P2 side and flows into parallel circuit (53) on P2 side. 4. The delivery oil passes through around bucket spool (5). For items ➂ and ➃ . The proportional valve secondary pressure from P2 cut proportional valve (PSV-B) acts on PCa port on arm variable recirculation & P1 cut section of block on P2 side and moves P2 cut spool (12) upward. the return oil from the bucket cylinder rod side flows through bucket dumping circuit (61) and C/V Ac port. and for others the operation is the same as the digging operation. 7. 53) on P1 and P2 sides are connected. 52) on P1 and P2 sides. The bucket conflux circuit functions only when the independent operation. but it comes to a stop because P2 cut spool (12) on the arm variable recirculation & P2 cut section of block on P2 side is moved. 2. 5. and by-pass circuit (52) on P2 side starts closing. the operation is the reverse of the bucket section. The reason why arm conflux variable recirculation and P2 cut on P2 cut section actuate is that the oil in A chamber flows into drain circuit (57) through passage B at the center of spool (12). Concurrently. With bucket digging operation. with the bucket digging operation. and parallel circuits (51. P1 pump delivery oil flows into by-pass circuit (51) on P1 side and parallel circuit (51) on P1 side through P1 port of block on C/V P1 side. The delivery oil passes through around the bucket spool. 2. and is led into bucket spool (5). 11. opens load check valve (21) LCc. Note: 1. P2 pump delivery oil flows into by-pass circuit (52) on P2 side on the upperstream of travel straight section through P2 port of the block on C/V P1 side. low pressure sensor (SE1) senses and outputs the command current into P2 cut (PSV-B) and travel straight (PSV-C) valves on the solenoid/proportional valve block command current through mechatro controller. Dynamic Acera 01/2002 Page 7-26 . 9. Concurrently. CONTROL VALVE BUCKET DIGGING SK330 • Bucket digging operation (Conflux circuit) (SK330) 1. Note: 1. The delivery oil opens load check valve (21) CT1 through parallel circuit (51) on P1 side and flows into the downstream. And the proportional valve secondary pressure acts on PTb on the travel straight section of the block on P1 side and moves travel straight spool (1) upward. and finally returns into hydraulic tank through tank circuit (56). 12. 13. because the travel straight spool (1) on the travel straight section. 3. the delivery oil flows into by-pass circuit (50) because travel straight spool is moved. The P1 and P2 delivery oil is confluxed in parallel circuit (51) on P1 side. 4. The pressure oil passes through perforation around slewing spool (4). 2. and flows into slewing left rotation circuit (67) and is led into slewing spool (4). With slewing right operation. and by-pass circuit (52) on P2 side closes. 7. and finally the delivery oil flows into parallel circuit (53) on P2 side. 3. load check valve (21) CP1 on the downstream of travel left section opens. The pressure oil flows into P chamber in the inside of spool through perforation around slewing spool (4) and passes through perforation again. the pilot secondary pressure acts on PBs port on the slewing section of block on P2 side and moves bucket spool (4) upward. Because slewing spool (4) of the slewing section is moved. flows into Q chamber in the inside of spool and passes through perforation again. Slewing right operation 1. 5. and is led into by-pass circuit (52) on P2 side. On the other hand. And the pressure oil opens load check valve (21) LCs through parallel circuit (53) on P2 side and reaches to slewing spool (4) through U-shaped passage (75). and finally returns into hydraulic tank through tank circuit (56). Dynamic Acera 01/2002 Page 7-27 . the return oil from the slewing motor B port flows through C/V As port from slewing left circuit (67) and is led into slewing spool (4). P2 pump delivery oil flows through the travel straight section through the P2 port of block on C/V P1 side from by-pass circuit (52) on P2 side on the upperstream of the travel straight section. 6. CONTROL VALVE SWING 6. 4. Then. the slewing operation is allowed even under the conditions such as push-on digging. Note: For details of for each operation. Usually. see Articles for arm-in and slewing right operation. resulting in the high working pressure. arm variable recirculation spool (13) is switched in the recirculation cut condition. CONTROL VALVE SWING AND ARM IN 9.. 2. consequently the recirculation cut and sequence confluxing operation are not performed. the slewing priority control functions. Dynamic Acera 01/2002 Page 7-28 . but when it is operated concurrently with slewing operation. and arm variable recirculation spool (13) is switched forcedly to the recirculation condition. With arm-in and slewing right simultaneous operation. where the slewing load is higher than the arm operating load. the arm variable recirculation control command varies according to the slewing right operation pilot pressure. And. etc. Arm-in and slewing simultaneous operation (Slewing priority circuit) 1. when the pumping load becomes high (P2 pressure: 200 kgf/cm² or more). therefore the return oil from the rod side is used in precedence to others. And the P2 pump delivery oil flows into the slewing section as the working pressure is low in precedence to others. arm spool (9) and arm variable recirculation spool (13) move down and slewing spool (4) moves up the same as in respective independent operation. slant digging. 3. securing the arm operating speed at the same time.