GB1422470A - Measuring boss - Google Patents

Abstract

1422470 Driving vehicle wheels; measuring wheel forces R WEBER 22 March 1973 [23 March 1972] 13978/73 Heading B7H [Also in Division G1] A transducer which measures the forces and moments acting on a rotating member, e.g. a vehicle wheel, comprises two coaxial parts which fit around the shaft of the rotating member, the inner part bears on the shaft through a roller bearing while the outer part is fixed to a support. Each part has a radially extending flange which is joined to a flange of the other part by bolts which carry strain gauges and which lie parallel to the shaft. The forces acting on the rotating member are transmitted via the shaft and the roller bearing to the inner part of the transducer, thus stressing the bolts and altering the strain gauges. In Fig. 2 the inner and outer parts are shown at 11 and 10. The inner part 11 has a flange 18, seen in the upper part of the drawing, which is joined by bolt 21 to flange 17 of the outer part. The inner part has a further flange at its other end shown at 19 in the upper part of the drawing, but bolt 21 passes through that flange without touching it. The bolt 21<SP>1</SP> shown in the lower part of the drawing is diametrically opposite bolt 21 and it connects flange 19 to a flange 16 of the outer part and passes through flange 18 without touching it. An even number of such bolts are used and they alternately connect flange 18 to flange 17 and flange 19 to flange 16, Fig. 3 (not shown). The inner part 11 bears on a hollow wheel shaft 14 via bearings 12, 13, while the outer part is fixed to a support (not shown). To permit a degree of flexibility in the assembly the wheel flange 15 is driven by an intermediate shaft 38 passing through the hollow shaft 14, flexible diaphragms 36 and 37 being provided at its ends. The right hand end of shaft 38 is driven from shaft 20 via constant velocity joint 31. This flexibility allows radial, axial and flexual motion between the transducer parts. In another embodiment, Fig. 3a (not shown), the flanges are shaped such that flanges 17 and 19 lie in a plane, and flanges 16 and 18 are also coplanar. Fig. 4 shows the disposition of the strain gauges 1-6 on four bolts. Each bolt carries four gauges at its centre and two gauges at one end. Bridge circuits using various combinations of these gauges are given, Figs. 5-9 (not shown), which allow the forces P, S, U and moments M R , M S shown on Fig. 4 to be measured. At least four bolts are required, and they may be made hollow to increase the sensitivity.