DESCRIPTION MCV106A Hydraulic Displacment Control-PV Issued: March 1991 The MCV106A Hydraulic Displacement Control (HDC) is a costeffective hydraulic pump stroke control which uses mechanical feedback to establish closed-loop control of the swashplate angle of Danfoss Series 2X and Series 3X pumps. The HDC accepts a differential hydraulic pressure signal from a control handle or servovalve and uses the differential pressure to drive its double spool arrangement and port oil to the pump servocylinders. The spool configuration allows a neutral deadband for machine safety in the pump s output while maintaining optimum dynamic response to control commands. FEATURES Servo control deadband independent of signal neutral deadband: offers safety combined with accurate and responsive control. Resistant to the environment: shock, vibration and humidity tested. High porting spool force resists chip plugging. Swashplate movement can be visually detected at the feedback shaft. Low cost. ORDERING INFORMATION A range of options to the basic HDC allows it to be customtailored to each application. The control is specified by filling in each slot of the order number, as is shown in Table A, with the appropriate model code. Other options are possible. Consult Danfoss with further questions. TABLE A. INFORMATION NECESSARY TO SPECIFY THE HDC. MCV106A X 9 XX DEVICE IDENTITY CONFIGURATION MODEL MODULATING PRESSURE RANGE 1. DEVICE IDENTITY This is the basic HDC. The model code is MCV106A. 2. CONFIGURATION MODEL PRESSURE CODE LIMITER OR CONTROL PRESSURE OVERRIDE 5 No * No 6 No Yes 7 Yes ** No 8 Yes * Yes * Pressure Override Only ** Model Code 7 Devices May Not Be Used On Series 3X Pumps The Pressure Override and Pressure Limiter accomplish the same function - they shift the pump swashplate toward neutral when system pressure crosses a pre-set threshold. They thus limit system pressure, protect components from heat generated by flow across relief valves and conserve pump horsepower. Pressure override is available only for Series 2X pumps, and pressure limiting is available only for Series 3X pumps. Pressure limiting and annular control are not available together. If the model code chosen indicates that the pressure override/pressure limiting function is desired (i.e., yes is chosen in the second column of the configuration parameter, above), only pressure limiting will be provided directly by Danfoss (pressure limiting is accomplished using a different porting spool); the Pressure Override Valve must be obtained through Danfoss. Stroke controls with annular control have a groove cut into the spool bore of the housing that allows for higher flow from the control ports when they are uncovered, increasing swashplate response. 3. MODEL The model code is "9". Danfoss, 2013-09. 1.
ORDERING INFORMATION (continued) 4. MODULATING PRESSURE RANGE MODEL DIFFERENTIAL DIFFERENTIAL CODE THRESHOLD FULL-STROKE PRESSURE MODULATING PRESSURE 01 12 psid 153 psid 02 120 psid 550 psid 03 217 psid 435 psid 04 44 psid 160 psid 05 80 psid 300 psid 06 13 psid 98 psid The threshold and full stroke modulating pressures come in three ranges, as shown above. The threshold (the amount of differential pressure necessary to move the actuator spool) and full stroke (the amount of differential pressure necessary to yield maximum swashplate displacement) ranges should be chosen so as to be compatible with the hydraulic signal from the command source, which is usually a control handle. The full stroke figures shown are nominal. 02 and 03 models use a spacer plate which makes the body longer, as shown in the Dimension drawing. Order Danfoss Pressure Override Valve through Danfoss distributors. Consult Danfoss, Ames, Iowa at (515) 239-6000 for further information. Linkage kits, custom fitted for the proper pump series, must be ordered along with the valve. Which kit is shipped with the HDC depends on which pump series is ordered and the pump type. Included in the kit are: retaining rings, swashplate pin, drag link, orifice, hex screws, O-rings and gasket. In some cases not all of the above are necessary for installation, and they are not included with the kit. Order per Table B. TABLE B. LINKAGE KIT ORDERING INFORMATION. PRODUCT TYPE KIT TYPE PUMP SERIES 1. PRODUCT TYPE The model code is "06". 2. KIT TYPE MODEL CODE DESCRIPTION 3 Standard HDC 4 HDC with POR 3. PUMP SERIES 20-27, 33, 34, or 36. Order additional linkage assemblies through Danfoss. SPARE PARTS KK For a complete list of spare parts see the Spare Parts Section of this book. Contact Danfoss for application assistance. 06 X XX 2
SPARE PARTS 10 15 3 4 14 9 11 12 13 8 7 6 5 16 17 18 1 2 1379 ITEM NUMBER PART NUMBER DESCRIPTION ITEM NUMBER PART NUMBER DESCRIPTION 1 K07009 O-Ring 9 K07034 Screw, 1/4-20 X 0.75 2 K07160 Bushing (Non Spacer models) 3 K08621 Cover, Null adjust 10 K07181 Spacer 4 K08133 Gasket 11 K07159 Plug 5 K07128 Filter Screen 12 K07010 O-Ring 6 K07011 O-Ring 13 K08387 3/8 Seal Washer 7 K07028 Plug 14 K08132 Gasket (Spacer models) 8 K07000 Nut, 3/8-32 15 K08601 1/4" Seal Washer 9 K07035 Screw, 1/4-20 X 1.5 16 K07182 HDC Gasket (Spacer models) 17 K07006 Port O-Rings 18 K07136 Orifice TECHNICAL DATA HYDRAULIC OIL VISCOSITY - 40 to 121 C (-40 to 250 F) operating range OIL TEMPERATURE 40 TO 121 C (-40 TO 250 F) operating range 21 to 82 C (70 to 180 F) rated performance range - 2X Series 21 to 104 C (70 to 220 F) rated performance range - 3X Series MINIMUM SYSTEM FILTRATION B 10 = 2 or better (10 micron nominal) RATED CASE OPERATING PRESSURE 40 psi. OPERATING CHARGE PRESSURE 150-600 psi above case pressure FLOW RATING 0.7 to 1.1 gpm (std.), 1.2 gpm minimum (annular) total at saturation with cylinder ports connected and 200 psi supply pressure. 3
DIMENSIONS 1170B Dimensions of the MCV106A in Millimeters (Inches). 4
THEORY OF OPERATION The HDC uses a unique double spool arrangement that serves to separate the null deadband from the feedback, giving both safety against null drift and quick dynamic response to command changes. The command signal for the MCV106A is usually a remote hydraulic control handle, as shown in the Block Diagram, although other pressure sources could be used. The handle modulates charge pressure from the pump (or another source) so as to apply a proportional differential pressure across the C1 and C2 input ports. The HDC s null adjust is factory set with the modulating spring compressed to the equivalent of the threshold pressure (see Technical Data section), depending on the output characteristics of the command source, representing the differential pressure required to move the actuator spool one direction or the other. This is a factory setting that defines the width of the actuator spool deadband and cannot be changed in the field. By tightening or loosening the null adjust screw, the fixed deadband is moved toward or away from a symmetrical neutral position. As differential control pressure (C1 - C2) rises beyond the deadband, the actuator spool moves in one direction or the other, pivoting the crosslink about its center. The pivoting crosslink pushes or pulls the porting spool in the opposite direction of the actuator spool. When the porting spool has moved far enough to open A or B to charge pressure, oil is ported to the pump servocylinders to move the swashplate. As the swashplate moves, the feedback link follows, pivoting the crosslink about the stationary end of the actuator spool, driving the porting spool back toward its neutral position. Because the feedback signal is entered into the control loop after the command has been input, response time and accuracy are enhanced. INTERNAL WORKINGS SCHEMATIC OF THE MCV106A 1171B Control Handle Supply Pressure May Also Be Provided By an Auxiliary Pilot Pump. 5
PERFORMANCE MODULATING RANGE 141 psid (MCV106AXX01) 430 psid (MCV106AXX02) 218 psid (MCV106AXX03) 116 psid (MCV106AXX04) 220 psid (MCV106AXX05) 85 psid (MCV106AXX06) MAXIMUM HYSTERESIS 4% of modulating range when cycled at.01 Hz THRESHOLD PRESSURE 12 ± 6.4 psid (MCV106AXX01) 120 ± 15.5 psid (MCV106AXX02) 217 ± 8.1 psid (MCV106AXX03) 44 ± 4.6 psid (MCV106AXX04) 80 ± 8.1 psid (MCV106AXX05) 13 ± 3.5 psid (MCV106AXX06) SENSITIVITY A 1%-of-modulating-range change in output differential pressure will cause a detectable output change. NEUTRAL LEAKAGE.10 gpm maximum std.,.18 gpm maximum annular across the valve with 145-160 SUS oil @ 38 C (100 F) RESPONSE TIME See Table C. DIMENSIONS See the Dimension drawing. TABLE C. MAXIMUM RESPONSE TIME IN SECONDS, OF STAN- DARD (NON-, NON ORIFICE), AND.052 HDC'S. CHARGE PRESSURE IS LESS THAN 250 PSI. RETURN TO NEUTRAL TIMES ARE AP- PROXIMATELY 60% OF FULL TO FULL. SERIES TYPE FULL TO FULL 20 20 20 21 21 21 22 22 22 23.6 1.9.4.7 2.1.5 1.0 2.9.7 1.0 23 23 24 24 24 25 25 25 26 26 26 27 27 27 33, 34 33, 34 33, 34 36 36 36 3.0.7 1.6 5.0 1.1 1.9 5.7 1.3 4.3 13.0 3.0 4.9 15.1 3.4.9 1.8.5 1.4 2.8.8 ENVIRONMENTAL SHOCK 50 g for 11 milliseconds. Three shocks in both directions of the three mutually perpendicular axes for a total of 18 shocks. 2. Resonance dwell for one million cycles for each resonance point in each of the three axes. Subject to acceleration levels of 1 g to 46 g. Acceleration level varies with frequency. VIBRATION Withstands a vibration test designed for mobile equipment controls consisting of two parts: 1. Cycling from 5 to 2000 Hz in each of the three axes. 6
INSTALLATION A highly reliable connection between the swashplate and the drag link is necessary for safe operation. An unreliable connection may result in loss of feedback with a resulting loss of control. Series 3X pumps meet this requirement, but all Series 2X units not already equipped with an HDC or EDC must be retrofitted with the appropriate drag link, press fit pin and retaining ring, replacing the slip fit headless pin and E- rings used to attach the original drag link. Series 3X pumps with serial numbers of 82-34-00000 or greater will accept the HDC without modification of the pump. These units have a clearance notch cast into the swashplate WARNING The control and feedback link must have the proper identification in order to be installed. Installing a control with an improper feedback link can result in a control failure which can cause the pump swashplate to move to full angle and remain there independent of signal input. Do not attempt to install an HDC on a pump for which it was not originally designed without using the full linkage assembly. Merely changing the drag link is inadequate. See Ordering Information for linkage assembly numbers. that provides additional room for link movement. Series 3X pumps with serial numbers of less than 82-33-99999 may not be fitted with the HDC without modification of the swashplate by Danfoss. Prior to mounting any control on a pump, ensure that both the control and the feedback link are correct for the pump as evidenced by the series number stamped on the link and the part number labeled on the control body. See Table D. TABLE D. TABLE D CORRELATES THE PUMP SERIES NUMBER WITH THE SERIES NUMBER STAMPED ON THE SIDE OF THE FEEDBACK LINK PROTRUDING FROM THE CON- TROL. SERIES LINK MARKING 20, 20 (no spacer) 21, 22 21, 22 23 23 24 24 25 25 26 26 27 27 33, 34, 36 33, 34, 36 Installing a control not designed for use with the Pressure Limiter on 33, 34 and 36 Series pumps will prevent the Pressure Limiter from operating. MOUNTING SWASHPLATE DRAG LINK Follow the procedure outlined below to attach the HDC to the pump. REMOVING THE OLD HARDWARE 1. Thoroughly clean all external surfaces of the pump and control with steam or solvent. Blow dry. 2. Remove the existing control from the pump by removing the nine hex screws from the housing. Slip the pin on the control linkage out of the end of the drag link. See the Swashplate Drag Link photograph. 3. Remove the case drain fitting from the side of the pump on which the control was mounted. 4. Remove the E-ring from the inside end of the connecting pin. Use caution not to drop the E-ring into the housing during the removal. See the Pin Connection drawing. 5. Remove the pin from the drag link and swashplate through the case drainport using a magnet or other tool. Remove the drag link. On some models it may be necessary to hold the swashplate off neutral to align the pin with the case drain hole. See the Swashplate Location Drawing. 1124B Swashplate Drag Link/Control Feedback Link Connection Between Original Control and Pump. 7
MOUNTING THE NEW HARDWARE 1. Re-check the series number on the control feedback link to ensure that it is compatible with the pump. Follow the procedure outlined below to install the linkage: A. Unscrew the bushing, using care not to damage its O-ring. See the Parts Location photograph. B. Install the new linkage assembly shaft through the swashplate feedback shaft hole. Place the ball in the crosslink ball cavity. C. Lubricate the shaft O-ring and replace the bushing over the shaft. Torque to the body (10-15 footpounds) so that the feedback shaft extends through the bushing. D. Install the retaining ring in the groove on the shaft. 2. Align one end of the replacement drag link with the holes in the swashplate link arms. 3. Insert the press fit pin through the case drain port to trap the drag link in the swashplate clevis. It will be necessary to tap the pin into place until the head of the pin is flush to the clevis. SWASHPLATE LOCATION 4. Install the retaining ring by forcing it onto the tapered end of the pin until it locks into the recess on the pin shaft. Again, use caution not to drop any components into the pump housing. 5. One.052 inch diameter orifice must be installed in each servo port if reduced swashplate response is desired. 6. Engage the pin on the control in the drag link and swing the control into place against the pump housing. The drag link should be on the cylinder block side of the swashplate. Install the seven mounting screws and tighten to 10-11 foot-pounds of torque. 7. Connect the pipe or tubing from the control handle into the C1 and C2 ports (9/16-18 UNF threads per SAE J514). Phasing of the HDC is such that a pressure rise at the C2 port causes a pressure rise at the A output port of the pump, given a clockwise pump prime mover rotation as viewed into the input shaft. PIN CONNECTION TO SWASHPLATE RAG LINK 1126B 1125C Location of Swashplate Assembly in Pump Housing. PARTS LOCATION Shown Disassembled for Clarity. PUMP PORTS LOCATION LINKAGE ASSEMBLY CROSSLINK BALL CAVITY CASE DRAIN PORT SWASHPLATE FEEDBACK SHAFT HOLE BUSHING RETAINING RING 1173 CHARGE PRESSURE GAUGE PORT 1172 Location of Parts When Installing a New Link and Ball Assembly. Location of Pump Ports. 8
PUMP NEUTRAL ADJUSTMENT Use the following procedure to bring the Pump to neutral once the Hydraulic Displacement Control has been mounted. 1. Install a 600 psi gauge into the charge pressure gauge port on the pump. See Pump Ports Location photograph. 2. Using 1 9/16 - inch wrench, loosen the hex lock nut on the null adjustment screw. See Dimensions drawing. 12345678901234567890123456789012 WARNING 12345678901 2 To adjust neutral requires operating the pump. Take the necessary safety precautions such as having unnecessary personnel stand away from the machine. Maximum system pressure may occur upon start up, and the machine may move. Ensure that the operator is not in a position to be injured should the machine move. 3. Set the hydraulic control handle to neutral. 4. Start the prime mover and run at low idle. 5. Warm the system up for several minutes to bleed air. 6. Slowly increase the prime mover speed to rated rpm. 7. If the transmission operates as shown by motor shaft rotation, reduce speed to idle. Using a 3/16 inch internal hex wrench, slowly turn the null adjustment screw clockwise or counterclockwise until the transmission does not operate. Repeat step 6. Note that charge pressure should drop approximately 20 psi with forward or reverse stroking of the pump swashplate due to the shifting of the shuttle valve in the motor manifold. 8. With a 3/16-inch internal hex wrench, slowly turn the null adjustment screw clockwise until charge pressure begins to decrease. Then slowly turn the adjustment screw counterclockwise, observing the angle of rotation, until charge pressure decreases again (charge pressure will rise in neutral and drop when going into stroke). 9. Turn the adjustment screw clockwise half the amount of the turn observed in step 8. This should be the center of neutral. 10. Hold the adjustment screw and securely tighten the hex lock nut on the adjustment screw to 14-18 foot-pounds. Note that if a motor is used which does not have a manifold, neutral should be adjusted (steps 8-10) by observing the motor output shaft rotation without a load. 11. Stop the prime mover. 12. Run the system briefly to ensure that it operates proportionally on both sides of the null command. Swashplate movement can be verified by watching movement of the swashplate feedback shaft, shown in the Dimension Drawing. CUSTOMER SERVICE NORTH AMERICA ORDER FROM Danfoss (US) Company Customer Service Department 3500 Annapolis Lane North Minneapolis, Minnesota 55447 Phone: (612) 509-2084 Fax: (612) 559-0108 DEVICE REPAIR EUROPE ORDER FROM Danfoss (Neumünster) GmbH & Co. Order Entry Department Krokamp 35 Postfach 2460 D-24531 Neumünster Germany Phone: 49-4321-8710 Fax: 49-4321-871-184 For devices in need of repair, include a description of the problem, a copy of the purchase order and your name, address and telephone number. RETURN TO Danfoss (US) Company Return Goods Department 3500 Annapolis Lane North Minneapolis, Minnesota 55447 9