Bosch Rexroth. The Drive & Control Company - · PDF file09.10.2014 | Yinuo Shi, Advanced...
Transcript of Bosch Rexroth. The Drive & Control Company - · PDF file09.10.2014 | Yinuo Shi, Advanced...
09.10.2014 | Yinuo Shi, Advanced Engineering Pumps and Motors | © Bosch Rexroth AG 2014. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.
SIMPACK User Meeting – Augsburg / 8. + 9. October 2014
Bosch Rexroth. The Drive & Control Company
Modeling Axial Piston Pumps of Swashplate Type in SIMPACK Yinuo Shi Advanced Engineering Pumps and Motors Bosch Rexroth AG / Mobile Applications
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09.10.2014 | Yinuo Shi, Advanced Engineering Pumps and Motors | © Bosch Rexroth AG 2014. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.
1. Introduction to swashplate axial piston pumps
2. Challenges in the modeling as multi-body system 3. Modeling in SIMPACK
4. Simulation results 5. Conclusion and next steps
Contents
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09.10.2014 | Yinuo Shi, Advanced Engineering Pumps and Motors | © Bosch Rexroth AG 2014. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.
Rotary group Splined gearing connection between
the cylinder and the drive shaft
Pistons and cylinder bores arranged to be coaxial to the drive shaft
Support of the slippers and the retaining plate on the swashplate (tilted plate)
Support of the swashplate on the housing through bearing (no contact to the drive shaft)
Introduction to swashplate axial piston pumps
Swashplate Cylinder
Drive shaft Piston
Slipper
∎ High pressure ∎ Low pressure
∎ Housing pressure
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09.10.2014 | Yinuo Shi, Advanced Engineering Pumps and Motors | © Bosch Rexroth AG 2014. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.
Principle of function Rotation of the cylinder with the drive
shaft through the splined gearing
Stroke of pistons within the cylinder bores during the rotation of the cylinder (depending on the swashplate angle)
Intake of hydraulic fluid on the inlet side (low pressure)
Discharge of hydraulic fluid on the outlet side (high pressure)
Efficient transmission of hydraulic power
Introduction to swashplate axial piston pumps
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09.10.2014 | Yinuo Shi, Advanced Engineering Pumps and Motors | © Bosch Rexroth AG 2014. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.
1. Introduction to swashplate axial piston pumps
2. Challenges in the modeling as multi-body system 3. Modeling in SIMPACK
4. Simulation results 5. Conclusion and next steps
Contents
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09.10.2014 | Yinuo Shi, Advanced Engineering Pumps and Motors | © Bosch Rexroth AG 2014. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.
Tribologic aspects for swashplate design Lubrication for main contact positions
Slipper swashplate contact Slipper retaining plate contact
Cylinder port plate contact Piston cylinder (bushing) contact
Solid contact due to asperity
Elastic and thermal effects
Challenges in the modeling as multi-body system
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09.10.2014 | Yinuo Shi, Advanced Engineering Pumps and Motors | © Bosch Rexroth AG 2014. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.
1. Introduction to swashplate axial piston pumps
2. Challenges in the Modeling as multi-body system 3. Modeling in SIMPACK
4. Simulation results 5. Conclusion and next steps
Contents
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09.10.2014 | Yinuo Shi, Advanced Engineering Pumps and Motors | © Bosch Rexroth AG 2014. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.
Potential methods Method 1:
Calculation of hydraulic pressure in external software Input in SIMPACK Interpolation for different operating states (rotating speed, swash angle, etc.)
Simplified force elements via expression in SIMPACK
Method 2: Cosimulation Method 3: User routines for simultaneous computation of hydraulic pressure
User routines for mixed lubrication (hydrodynamic lubrication plus asperity)
Adoption of method 3 for the current modeling and simulation in SIMPACK
Modeling in SIMPACK
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09.10.2014 | Yinuo Shi, Advanced Engineering Pumps and Motors | © Bosch Rexroth AG 2014. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.
Modeling of mechanical parts Substructures
Piston & slipper Cylinder
Retaining parts: retaining ball, retaining plate …
Swashplate Control and counter pistons
Drive shaft (with force element “Massless Beam Cmp”)
Model assembly by the “sender” & “receiver”
Modeling in SIMPACK
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09.10.2014 | Yinuo Shi, Advanced Engineering Pumps and Motors | © Bosch Rexroth AG 2014. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.
User routine for hydraulic pressure
Modeling in SIMPACK
User force element (SimUMST)
Input parameters: fluid data, nominal pressure, area profile,
geometric data, reference marker, …
Output parameters: pressure, force, flow rate, …
Pressures in piston chamber and slipper inner range as dynamic states
Leakage of tribologic contacts
De-/activation of slipper pressure mode
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09.10.2014 | Yinuo Shi, Advanced Engineering Pumps and Motors | © Bosch Rexroth AG 2014. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.
User routine for thrust bearing Application on slipper swashplate contact,
slipper retaining plate contact and cylinder port plate contact
Discretization of contact area to involve the rotation of the bodies
Solution of Reynolds equation for parallel lubrication film (1D-solution1) for each subarea (without elastic deformation) Simultaneous kinematic parameters – film thickness and its velocity –
obtained by SIMPACK access functions
Contact due to asperity Approach according to Patir2 (contact force due to surface roughness
if the film thickness is less than the reference value)
Modeling in SIMPACK
1: Derivation by Eric Quetel, Robert Bosch GmbH 2: N. Patir, Effects of surface roughness on partial film lubrication using an average flow model based on numerical simulation, PhD Thesis, Northwestern University, Illinois, 1978
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+ +
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09.10.2014 | Yinuo Shi, Advanced Engineering Pumps and Motors | © Bosch Rexroth AG 2014. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.
User routine for thrust bearing
Modeling in SIMPACK
User force element (squeeze force)
Input parameters: fluid data, boundary pressure, geometric data, parameters for mixed lubrication, …
De-/activation of mixed mode (due to asperity)
Output parameters: pressure, force, flow rate, …
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0
0.005
0.01
0.015
0.02
0.025
050
100150200
250300
350400
1
1.5
2
2.5
3
x 10-5
09.10.2014 | Yinuo Shi, Advanced Engineering Pumps and Motors | © Bosch Rexroth AG 2014. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.
Journal bearing Application on piston cylinder (bushing) contact
Method 1: constraint for parallel approach Method 2: user routine
Unwrapped lubrication film Discretization of Reynolds equation for
nonparallel lubrication film (without elastic deformation)
Simultaneous kinematic parameters – eccentricities and velocities – obtained by SIMPACK access functions
Contact due to asperity (surface roughness)
Modeling in SIMPACK
eccentricities
contact length
Film
thic
knes
s [m
]
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09.10.2014 | Yinuo Shi, Advanced Engineering Pumps and Motors | © Bosch Rexroth AG 2014. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.
User routine for journal bearing
Modeling in SIMPACK
User force element
De-/activation of mixed mode (due to asperity)
Output parameters: force, torque, kinematic parameters (for
reconstruction of pressure field), …
Kinematic parameters
Discretization in circumferential and translational directions
Boundary pressure, geometric and fluid data
front rear
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09.10.2014 | Yinuo Shi, Advanced Engineering Pumps and Motors | © Bosch Rexroth AG 2014. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.
Friction force Hydrodynamic friction force1
Piston cylinder (bushing): Couette-term due to viscosity and relative velocity (obtained by SIMPACK access function); Poiseuille-term due to boundary pressure difference Slipper swashplate: Couette-term due to
viscosity and relative velocity (obtained by the SIMPACK access function)
Mixed friction force due to asperity
Slipper swashplate: application of the friction coefficient and the surface contact force
Modeling in SIMPACK
1: Derivation by Eric Quetel, Robert Bosch GmbH
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09.10.2014 | Yinuo Shi, Advanced Engineering Pumps and Motors | © Bosch Rexroth AG 2014. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.
1. Introduction to swashplate axial piston pumps
2. Challenges in the modeling as multi-body system 3. Modeling in SIMPACK
4. Simulation results 5. Conclusion and next steps
Contents
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09.10.2014 | Yinuo Shi, Advanced Engineering Pumps and Motors | © Bosch Rexroth AG 2014. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.
Hydraulic pressure profile Computation of simultaneous
pressure profile, depending on
Geometry of control plate and piston-slipper throttle Kinematics, such as
translational and rotating speed, swash angle, etc.
Dynamic behavior due to elastic drive shaft (with force element “Massless Beam Cmp”)
Simulation results
Pressure in piston chamber and in the inner range of slipper
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09.10.2014 | Yinuo Shi, Advanced Engineering Pumps and Motors | © Bosch Rexroth AG 2014. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.
Thrust bearing (slipper contact) Squeeze force in outer and
inner range, depending on
Geometry of slipper Simultaneous film thickness,
velocity and boundary pressure
Solid contact force due to asperity, depending on
Material properties Surface roughness
Film thickness
Simulation results
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+ +
Segment 1
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09.10.2014 | Yinuo Shi, Advanced Engineering Pumps and Motors | © Bosch Rexroth AG 2014. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.
Journal bearing (piston bushing contact) Test for shaft speed run-up, instantaneous piston pressure, constant
eccentricities, but regardless of solid contact and friction
Resulting force, application point, and resulting torque
Simulation results
0
0.005
0.01
0.015
0.02
0.025
050100150200250300350400
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
x 107
simultaneous pressure distribution (unwrapped lubrication film)
Cir. dir. (0 – 2π)
Tran
sl. d
ir. (c
onta
ct le
ngth
[m])
[Pa]
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09.10.2014 | Yinuo Shi, Advanced Engineering Pumps and Motors | © Bosch Rexroth AG 2014. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.
Friction (hydrodynamic friction) Test for piston cylinder (bushing) friction considering shaft speed run-up
Couette-term due to viscosity and relative velocity Poiseuille-term due to boundary pressure difference
Simulation results
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09.10.2014 | Yinuo Shi, Advanced Engineering Pumps and Motors | © Bosch Rexroth AG 2014. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.
1. Introduction to swashplate axial piston pumps
2. Challenges in the modeling as multi-body system 3. Modeling in SIMPACK
4. Simulation results 5. Conclusion and next steps
Contents
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09.10.2014 | Yinuo Shi, Advanced Engineering Pumps and Motors | © Bosch Rexroth AG 2014. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.
Conclusion Development of MBS-models for axial piston units of swashplate design
in SIMPACK
Computation of pressure profile with respect to simultaneous kinematics of each part of the pump model
Description of hydrodynamic film lubrication by Reynolds equation
Solution for parallel film (thrust bearing, analytically for 1D case) Solution for non-parallel film (journal bearing, numerically for 2D case
through discretization) Description of solid contact force due to asperity
Integration of contact and friction forces into MBS-models by user routines
Conclusion and next steps
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09.10.2014 | Yinuo Shi, Advanced Engineering Pumps and Motors | © Bosch Rexroth AG 2014. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.
Next steps Application of numerical solution of
Reynolds equation for nonparallel film in the case of thrust bearing
Slipper swashplate contact Cylinder control plate contact
Integration into MBS by user routines Description of hydrodynamic and solid friction at all contact positions Reduction of simulation time by optimization of user routines and
solver settings
Elastic aspects (besides drive shaft)
Conclusion and next steps
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+ +
User experience – Suggestion to SIMPACK pre/communicators: override index, e.g., “SUBSTR_ID”, not only for receiver but also for sender.
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