This paper describes a dynamic model for slipper-pads that allows lift and tilt behavior to be predicted, including the effects of possible contact with the swashplate or slipper retaining plate. This model has been incorporated in the Bathfp simulation package and used to examine the dynamic stability of slipper-pads over the pumping cycle, and to compare the behavior over a range of pump speeds. The centripetal tilting moments acting on the slipper-pad increase with speed and as a consequence can lead to contact between the slipper and the swashplate at high speed. This is particularly likely to occur as the piston makes the transition between suction and delivery, where the pressure forces acting on the piston-slipper assembly change abruptly. The predicted nature of the swashplate contacts at high speeds correspond closely with witness marks on a dismantled pump. The model presented may also be used for predicting slipper behavior in other types of pump, for example, wobble-plate type pumps, or in piston motors.

1.
Harris, R. M., 1991, “The CAPPA Suite—Bathfp Model Reference Guide for Computer Aided Pump Performance Analysis, Part I,” School of Mechanical Engineering, University of Bath.
2.
Hooke, C. J., and Kakoullis, Y. P., 1978, “The Lubrication of Slippers in Axial Piston Pumps,” Proc. 5th International Fluid Power Symposium, Durham, 13th–15th September, Section B2, pp. 13–26.
3.
Hooke, C. J., and Kakoullis, Y. P., 1979, “On-Line Measurement of Film Thickness,” Proc. Conference on Instruments and Computers for Cost Effective Fluid Power Testing, I. Mech. E., London, Paper No. C128/79, pp. 51–59.
4.
Hooke, C. J., and Kakoullis, Y. P., 1981, “The Effects of Centrifugal Load and Ball Friction on the Lubrication of Slippers in Axial Piston Pumps,” Proc. 6th International Fluid Power Symposium, Cambridge, 8th-10th April, Section D2, pp. 179–191.
5.
Hooke
C. J.
, and
Li
K. Y.
,
1989
, “
The Lubrication of Slippers in Axial Piston Pumps and Motors—The Effect of Tilting Couples
,”
Proc. I. Mech. E. Part C.
, Vol.
203
, pp.
343
350
.
6.
Hooke, C. J., 1989, “The Design of Slippers for Axial Piston Pumps and Motors,” Components and Systems—Second Bath International Fluid Power Workshop, Research Studies Press, pp. 77–97.
7.
Iboshi
N.
, and
Yamaguchi
A.
,
1982
, “
Characteristics of a Slipper Bearing for Swash Plate Type Axial Piston and Motors (1st Report, Theoretical Analysis)
,”
Bulletin of the JSME
, Vol.
25
, No.
210
, pp.
1921
1930
.
8.
Iboshi
N.
, and
Yamaguchi
A.
,
1983
, “
Characteristics of a Slipper Bearing for Swash Plate Type Axial Piston Pumps and Motors (2nd Report, Experiment)
,”
Bulletin of the JSME
, Vol.
26
, No.
219
, pp.
1583
1589
.
9.
Lee, Y-C., 1989, “The Design Analysis about Sealing Lips on the Slipper Face and the Calculation of Balancing Factor with Practical Example,” Proc. 2nd International Conference on Fluid Power Transmission and Control, Beijing, China, pp. 302–304.
10.
Richards, C. W., Tilley, D. G., Tomlinson, S. P., and Burrows, C. R., 1990, “A Second Generation Simulation Package for Fluid Power Systems,” Proc. 9th International Symposium on Fluid Power, Cambridge, pp. 315–322.
11.
Tienong, Z., Decai, H., and Yongge, P., 1989, “Study on Dynamic Film Characteristics of the Slipper in Working Conditions,” Proc. 2nd International Conference on Fluid Power Transmission and Control, Beijing, China, pp. 284–288.
12.
Tokar
I. Y.
, and
Kanyuk
G. I.
,
1987
, “
Cavitation in Hydrostatodynamic Bearings of Hydraulic Machine Piston Elements
,”
Soviet Journal of Friction and Wear
, Vol.
8
, No.
5
, pp.
106
111
.
13.
Tokar
I. Y.
,
Kanyuk
G. I.
, and
Petrovskii
G. V.
,
1986
,
Soviet Journal of Friction and Wear
, Vol.
7
, No.
1
, pp.
71
76
.
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