Patent GB-736038-A (GB)
Title: Improvements in hydraulic dynamometers and brakes
Inventor: BATHURST WILLIAM NEVILE
IPC: G01L3/20
Filed: 1953-03-05
Abstract: 736,038. Dynamometers. HEENAN & FROUDE, Ltd. March 4, 1954 [March 5, 1953], No. 6096/53. Class 106 (2). [Also in Group XXXIV] In a hydraulic brake or dynamometer of the type comprising a rotor and a stator of circular cross-section, the working fluid passing between coacting surfaces of the rotor and stator, the rotor and stator are arranged coaxially one within the other with a slight clearance space between them and are capable of relative longitudinal movement to vary the effective area of the clearance space between them, power being absorbed by the passage of fluid in an axial direction through the clearance space. In the embodiment illustrated in Fig. 1, the invention is shown applied to a dynamometer in which the rotor A, driven through coupling a2, is supported by bearings B<SP>1</SP> and B<SP>2</SP> and is embraced by a stator C capable of being moved axially in relation to the rotor A, there being a clearance space between the outer surface of the rotor A and the inner surface of the stator C; the whole assembly being contained in a casing D mounted on trunnion bearings K<SP>1</SP>, K<SP>2</SP>. The axial position of the stator C relative to the rotor A is controlled by rotation of a handwheel H and the position indicated by means of an indicator j<SP>3</SP> which moves along a scale j<SP>4</SP> through gearing Jl, J<SP>2</SP>, J<SP>3</SP>. The working fluid of the dynamometer is fed, by means of a flexible pipe, into passage d<SP>1</SP> and thence through passages d<SP>2</SP>, d<SP>3</SP> and d<SP>4</SP> and between the clearance space between the rotor and the stator into the outlet passage e<SP>1</SP> and thence to a convenient sump for cooling and re-circulation; the temperature and viscosity of the working fluid which may be re-circulated being manually or thermostatically controlled. In order to regulate the amount of load absorbed by the dynamometer, the amount by which stator C overlaps the rotor A is varied by rotation of handwheel H. A finer degree of adjustment of the load may be achieved if the outer surface of the rotor A and the inner surface of the stator C are formed with a slight taper instead of being cylindrical. The torque applied to the casing by reason of the reaction of the rotor A and stator C can then be counterbalanced and measured in a known way by attaching a suitable weighing apparatus at the end of an arm secured to the casing. In the embodiment, applied also to a dynamometer, illustrated in Fig. 2, the rotor A<SP>1</SP> carried by shaft A<SP>2</SP>, embraces the stator C<SP>1</SP> with a slight clearance between them. The stator is slidable axially relative to the rotor A<SP>1</SP> in the casing D and is moved by means of rotation of the handle H. The working fluid is supplied through the passage d<SP>1</SP>, into chamber d<SP>2</SP>, through passages d3 and d<SP>4</SP> through the clearance between the rotor A<SP>1</SP> and the stator C<SP>1</SP> and along passages e<SP>2</SP> to the outlet e<SP>1</SP>. A modification to the embodiment illustrated in Fig. 1 is described in which a weir plate is provided to restrict the flow of the working fluid at the outlet end of the rotor. A vent (not shown) may be taken to atmosphere from the region of the compartment d<SP>5</SP> in order to maintain uniform pressure at the inlet side of the rotor A. The rotor and stator of the form illustrated in Fig. 1 may be provided with scallops, indentations or blading of any convenient form to facilitate the flow of working fluid from the inlet to the outlet sides of the rotor.