Vickers®Constant Pressure Reversible Power Transfer Unit

Part Number 971600 Model MPHV3-115-1C

2 EATON Aerospace Group TF500-1C August 2013

Model MPHV3-115-1C Power Transfer Unit

Eaton's Aerospace Group, a world leader in the design and manufacture of advanced power and motion control components, is the supplier of the bi-directional Power Transfer Unit (PTU) on board the Airbus A319/A320/A321.

Eaton has designed and manufactured the model MPHV3-115-1C PTU to meet Airbus’ overall design criteria for reliability, low noise, and high maintainability.

General Design Features

The model MPHV3-115-1C PTU consists of a fixed displace-ment hydraulic unit serving the aircraft’s green system and a variable displacement hydraulic unit serving the yellow system. The two units are connected via a single drive shaft so that power can be transferred between the two systems by the driveshaft. Depending on the direction of power transfer, each unit in turn works either as a motor or a pump.

The fixed displacement side of the PTU consists of a bent-axis hydraulic unit coupled with dual impellers to operate as low as 3 psia. The variable displacement side is an inline unit designed with a single impeller to operate as low as 3 psia. When power is transferred at a rate of 34 gpm (130 L/min) from the yellow system to the green system at a rate of 24 gpm (90 L/min), the displacement of the inline unit increases to function in the motoring mode while maintaining a constant pressure near 3000 psi (207 bar) in the green system.

Similarly, when power is trans-ferred at a rate of 16 gpm (60 L/min) from the green system to the yellow system at a rate of 13 gpm (50 L/min), the displacement of the inline unit is made to decrease in order to operate in the pumping mode while maintaining a constant pressure near 3000 psi (207 bar) in the yellow system.

When the pressure is near equal in both systems, the bi-directional power transfer unit does not rotate and stays in a standby condition. Under this condition, the variable displacement unit is at a displacement that is nearly equal to the bent axis unit.

The PTU is designed to meet Airbus operational requirements. These include:

• Compact envelope size

• High reliability

• Easy maintainability by separable units

• High response based on flow demands

• High stability at all required temperatures and flow directions

• High efficiency in both transfer directions

• Low inlet capability to prevent erosion and noise

• Low vibration

• Long service life for the unit

• Extremely low operating noise levels due to the location of the PTU on the pressure bulkhead in the wheel well of the aircraft

System Function of the Power Transfer Unit

Eaton's model MPHV3-115-1C PTU enables the green system to be supplied by the yellow system and vice versa without fluid exchange between the two systems. The PTU ensures essential flight functions by supplying the green system with additional power at constant pressure for the gear retraction should engine number one fail during take off, and similarly for the yellow system elevator servo control in the event of a dual failure of the blue and the yellow hydraulic system based on a failure of engine number two.

Ground maintenance functions are also facilitated by the MPHV3-115-1C PTU while the engines are shut down. The sub-systems associated with the green system can be operated on the ground by transferring power from the yellow system. Power to the yellow system is supplied by the on-board electric motorpump or possibly through a ground service cart. Also, the bi-directional capability of the unit makes possible the operation of the yellow system by means of transferring power by a ground service cart attached to the green system.

The only external control function of the PTU is accomplished via a switch in the cockpit, which energizes valves in the PTU supply lines of the yellow and green systems. This permits the complete isolation of the PTU and prevents hydraulic power transfer to or from either

system. These valves can be energized by the crew in flight at any time especially during warning indications, or activated by inhibition logic when the aircraft is on the ground during engine start-up.

Design Features

The MPHV3-115-1C PTU also incorporates a number of design features to maximize the reliability and maintainability of the PTU. These include:

• Increased fatigue strength by using finite element analysis methods coupled with improved material properties

• Improved cylinder block designs machined from steel for strength

• Ease of maintenance by designing a self-bleeding unit requiring no special procedures or tools. The PTU can also be removed or re-installed in the aircraft with no additional special tools.

• Filtered flow to the control valve to increase reliability

• The design of two separable units joined by a common foot allows easy maintenance at required intervals at an approved repair facility.

EATON Aerospace Group TF500-1C August 2013 3

Flow Reversal at Constant Pressure — Flow Schematic

3.50(83.7)

7.64

(194

.1)7.1

9(1

87.6)

2.87(72.8)

15°00’

1.25(31.8)

CASE DRAIN CONNECTION.5625-18UNJF-3A THDPER MS24423-6

CASE DRAIN CONNECTION.5625-18UNJF-3A THDPER MS24423-6

HIGH PRESSURE CONNECTION1.0625-12UNJF-3A THDPER MS21902J12

.80(20.3)

3.51(89) .22

(5.6)

SEEP DRAIN CONNECTION.4375-20UNJF-3A THDPER MS21902D4

.77(13.6)

4.72(120)MAX

2.85

(72.4

)5.2

0(1

32)

6.43

(163

.2)

2.37(60.2)

2.64(67)

2.35(59.6)

4 X 10.2(4 X .40)

4 X 11.2(4 X .44)

30°

6.85(174)

CENTER OF GRAVITY

LOW PRESSURE CONNECTION1.6250-12UNJ-3A THDPER MS21902J20

HIGH PRESSURE CONNECTION.8750-14UNJ-3A THDPER MS21902J10

3.69(93.7)

7.80(198.1)

9.16(232.8)

12.29(312.1)

6.61

(168

)

Ø .20(Ø 5.2)

C1 CONTROL PRESSURE

COMPENSATORVALVE

LOW PRESSURE

IMPELLER BOOST PRESSU RE

C2 CONTROL PRESSURE

CYLINDERBLOCK

PISTON

YOKE

CONTROL FLOWFILTER

SHAF TSEAL S. A.

CASE DRAINCHECK VALVE

CASE DRAINCHECK VALVE

COUPLINGSHAF T DRIVE

SHAFT

PISTO NSHOE

ACTUATO RPISTON

IMPELLER

ADAPTER ACTUATO RPISTON

IN-L INEHOUSING

BUSHING

CYLINDERBLOCK

PERIPHE RALIMPELLER

IMPELLER

IMPELLE RCOVER

BLOCKINGVALVE

IMPELLER PLATESUB ASSEMBLIES

BENT AXISHOUSING

HIGH PR ESSU REPORT

COMMONFOOT

HIGH PRESSUREPORT

YOKEPOSITION

FEED BACK

LOWPRESSURE

PORT

LOWPRESSURE

PORT

HIGH PRESSU RE

CASE PRESSURE

GREEN SYSTEMPUMP

YELLOW SYSTEMMOTOR

F ILTERED PRESSURE

Copyright © 2013 Eaton All Rights ReservedForm No. TF500-1CAugust 2013

Eaton Aerospace Group9650 Jeronimo RoadIrvine, California 92618Ph (949) 452 9500Fax (949) 452 9990www.eaton.com/aerospace

Eaton LimitedAerospace GroupFuel & Motion Control Systems DivisonLarchwood AvenueBedhampton, Havant Hampshire P09 3QLUnited KingdomPhone: (44) 2392 487260 Fax: (44) 2392 492400