Theoretical and Experimental Studies of the Steady State Performance of an Orbital Rotor Low-Speed High-Torque Hydraulic Motor

Abstract

In this paper the steady state performance of epitrochoid generated orbital ‘rotary piston machine’ (ROPIMA) type ‘low-speed high-torque’ (LSHT) hydrostatic unit has been studied. The complex variation of the volume of a chamber of such a machine with shaft rotation, along with the various flow and torque losses, demand a structured approach to arrive at its mathematical model. In conventional approaches the system morphology becomes obscured as the mathematical model is approached. Bondgraph provides a structured approach to model engineering systems in a simplified manner. A reduced Bondgraph model of the LSHT Orbital motor is made where the various losses are lumped in suitable resistive elements. The variations of the loss coefficients are identified. The predicted performance of the motor has been experimentally verified.

Keywords

orbital rotor LSHT hydraulic motor Bondgraph hydrostatic system

Get full access to this article

View all access options for this article.

References

Wilson

W. E.

Mathematical models in fluid power engineering. Hydraul. Pneum. Power, March 1967, 136–147.

Schlosser

W. M. J.

The overall efficiency of positive-displacement pumps. Hydraul. Pneum. Power, May 1969, 272–280.

Thoma

J. U.

Mathematical models and effective performance of hydrostatic machines and transmission. Hydraul. Pneum. Power, November 1969, 642–651.

McCandlish

Dorey

R. E.

The mathematical modelling of hydrostatic pumps and motors. Proc. Instn Mech. Engrs, 1984, 198B(10), 165–174.

Zarotti

G. L.

Nervegna

Pump efficiencies and approximations and modelling. Sixth International Symposium on Fluid power, Cambridge, April 1981, paper C3, pp. 145–164.

Dasgupta

K. D.

Mukherjee

Maiti

Modelling and dynamics of epitrochoid generated orbital rotary piston LSHT hydraulic motor: a Bondgraph approach. Trans. ASME, J. Engng for Industry, August 1996.

Maiti

Sinha

G. L.

Limits on modifications of epitrochoid used in rotary piston machines and the effects of modification on geometric volume displacement and ripple. Ing.-Arch., 1990, 60, 183–194.

Thoma

J. U.

Simulation by bond graph, 1990 (Springer-Verlag, Berlin).

Maiti

Distributor valve port sequences in epitrochoid generated rotary piston machine type hydrostatic units. Arch. Appl. Mechanics, 1992, 62, 223–229.

10.

BS 4617: 1970 Methods of testing hydraulic pumps and motors for hydrostatic power transmission (British Standards Institution, London).

11.

Maiti

Studies on orbital rotary piston ‘LSHT’ hydrostatic motor low speed performance and design. PhD thesis, Department of Mechanical Engineering, Indian Institute of Technology, Kharagpur, 1990.