Download - ME597-lecture5-13
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Dr. Monika IvantysynovaMAHA Professor Fluid Power Systems
Design and Modeling of Fluid Power SystemsME 597/ABE 591 Lecture 5
MAHA Fluid Power Research CenterPurdue University
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Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 5912
Axial piston pump design solutions (swash plate and bent axis)
Radial piston pumps and motors piston support
Gear Pumps internal and external axial and radial gap compensation
Vane pumps advantage and disadvantage of this design
Displacement Machines
Study different design principles and learn about the following topics
Aim: - To be able to select the right design for your system application! - Knowledge about limitations of each basic design - To apply models on system level for each design
Please study the appropriate chapters in Ivantysyn, J. and Ivantysynova, M. (2001), Hydrostatic Pumps and Motors.Akademia Books International. New Dehli. ISBN-81-85522-16-2
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Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 5913
Displacement Machines
Fixed displacement machines Variable displacement machines
Piston Machines
Gear Machines
Screw Machines others
Axial Piston Machines
Radial Piston Machines
In-line Piston Machineswith external piston support
Swash Plate Machines
Bent Axis machines
Annual Gear
F
F
F
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with internal piston support
External Gear
Internal Gear
Vane Machines
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Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 5914
Bent axis axial piston pumps
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Synchronization of cylinder block
Using a universal joint
Using a bevel gear
Cylinder blockDriving flange
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Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 5915
Bent axis axial piston pumps
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Cardan joint
Synchronization of cylinder block connecting rod
Synchronization by pistons
piston
Piston rod
Synchronization by piston rod
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Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 5916
Kinematics of bent axis pumps
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Frame (1)
Driving flange (2)
Piston (3)
Cylinder (4)
Four link 3D mechanism
Assuming a fixed connection between link 2 and link 4, achieved by synchronizationmechanism has finally two degreesof freedom
Five link 3D mechanism
Frame (1) Cylinder (4)
Piston (3)
Driving flange (2)
Piston rod (5)
the mechanism has finally threedegrees of freedom
Piston can rotate about z 3 -axisPiston can rotate about z3-axis and piston rod can rotate about z5-axis
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Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 5917
Piston Design
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Short piston with piston rod
Spherical piston with piston ring
Long piston with piston rod
Conical piston with piston rings
Synchronization by universal joint or bevel gear
Synchronization by pistons or piston rods
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Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 5918
Design Examples
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Driving flange bearings
Spherical valve plate
Pump control device
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Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 5919
Design Examples
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Conical piston
Spherical valve plate
Driving flange bearings Fixed displacement pump
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Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59110
Radial Piston Pumps
with external piston support with internal piston support
eccentricity
Suction
Delivery
Stroke ring
Rotating cylinder body
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Stationary cylinder body
Rotating cam or crankshaft
Suction
Delivery
Displacement volume adjustable by changing eccentricity e
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Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59111
Radial Piston Pumps
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with external piston support
Multiple stroke radial piston pumps
Stationary stroke ring
Rotating cylinder bodywith internal piston support
Stationary cylinder body
Rotating cam
Only fixed displacement pumps realizable!
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Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59112
Piston support on outer stroke ring
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Stroke ring
Stroke ring Plane valve plate
Rotating cylinder body
Piston
Piston rotation enforcedby friction force Ff
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Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59113
Piston support on outer stroke ring
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Stroke ring borne in roller bearings
Stroke ring
Piston roller guide
Piston
Piston sliding bearing
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Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59114
Piston support on outer stroke ring
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Ball joint inside the piston
Slipper support Stroke ring
Hydrostaticallybalanced slipper
Hydrodynamicallybalanced slipperSlipper pocket
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Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59115
Stroke ring support
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Using a sliding carriage supported using line contact
Stroke ring mounted on a pivot
Change of eccentricity by pivotingthe stroke ring about pivot axis
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Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59116
Design Example
Control journal
Slipper
Stroke ring
Piston
Pump control system
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Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59117
External gear pump
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Basic principle
Inlet Outlet
Driving gear
Driven gear
Housing
Axial gaps between housing and the gear pair must be very small to seal thedisplacement chamber
Radial gaps between teeth addendum circle and housing
Qe = V n -Qs
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Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59118
Two stage gear pump
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Driving gear
Driven gearDriven gear
Inlet 1
Inlet 2
Outlet 2
Outlet 1
Outlet 1 and inlet 2 can be connected
or the pump can have two separate outlets
p1
p2
p4
p3
p2 = p3
p1 = p3the driving gear is pressure balanced!
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Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59119
Internal gear pump
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PinionInternal gear (ring gear)
Suction zonePressure zone
Crescent shaped divider
Using teeth of standard involute design requires a combination where thepinion has two or more fewer teeth than the ring gear! Pinion and ring gearare then separated by a crescent shaped divider.
Advantages:Better suction ability
Higher efficiencyMore compact designLess noise emission
Longer duration of teeth meshing leads to better sealing function
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Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59120
Internal gear pump
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Many different tooth profiles have been applied in the recent past.
Crescent shaped divider
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Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59121
Annular gear pumps
Applying specially generated tooth curves it can be achieved, that the innerrotor (the pinion) has only one tooth less than the ring gear, thus eliminating thecrescent-shaped divider.
Gerotor pump
Each tooth of the pinion maintainscontinuous sliding contact with atooth of the ring gear, providingfluid tight engagement.
Relative sliding velocity betweenpinion and ring gear is very small
quiet operation and longservice life
Outlet Inlet
Ring gear (z2)
Pinion (z1)
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Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59122
Annular gear pump Orbit principle
Ring gear (z2) fixed
Displacement volume isgiven by z1 times z2 toothspaces
Multiple delivery ofeach tooth space
Rotatingdistributor
Inlet OutletRotating pinion (z1)
2 Pressure port
1 Suction port
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Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 5912318
Pressure compensated axial gaps
Sealing ring
Sliding bearing
Gear pair
Bearing bushings
Shaft seal
End cap Front coverhousing
Pressurized area A
Only one direction of shaft rotation possible!
FZ FZ
Axial gap
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Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59124
Pressure compensated axial gaps
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Pressurized areaDriving gear
Driven gearSliding bearings
Sealing
Axial gap pressure compensated
Improved volumetric efficiency
2FZ
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Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59125
Pressure compensated radial gaps
Radial gap compensation
Pressurized areaAxial gap compensation
Bearing bushing
Small pressure zone achievable
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Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59126
Gear pump design example
Shaft seal
Bearing bushing performing a radial and axial gap compensation
Driving gear
Driven gear
inletoutlet
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Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59127
Internal gear pump- design example
Ring gear Pinion special shaped divider
Internal gear pump with axial and radial gap compensation
inlet
outletMoveable bearing shellPressurized area
Radial gap compensation
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Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 5912822
Screw Pumps
With two meshing screws
inlet
outlet
With two meshing screws
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Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 5912923
Screw Pumps
With three meshing screws
outlettthread pitch
inletoutlet
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Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59130
Vane PumpsClassification of vane pumps
Unbalanced vane pump
RotorStatorBalanced vane pump
Only fixed displacement pumpFixed and variable pump design
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Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59131
Vane pumps- basic working principle
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inlet
inlet
outlet
Single stroke vane pump variabledisplacement volume
Large radial forces exerted on the rotor
Limitation of max. operating pressure (20 MPa)
Overcenter pump the direction of flow can be re-versed by change of eccentricity, i.e. without changing the direction of rotation of the drive shaft
outlet
no flow!Relatively high friction between axial moveable vanes and rotor
&between vanes and stator
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Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59132
Vane pumps- classification
Multiple stroke vane pump
Rotor
Rigid vane pump
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Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59133
Fluid distribution
Internal fluid distributionExternal fluid distribution
inlet
outlet
Distributor - fixed control journal
rotor
stator
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Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59134
Rigid vane pump
vane
Rotor
Stator ringDisplacement volume:
1st rotor 2nd rotor
Pulsation free flow