Wheel balance measuring apparatus

Abstract

A wheel balance measuring apparatus includes a frame, a hollow rim support shaft rotatably supported by the frame through a bearing, a lower rim mounted on the hollow rim support shaft, and an upper rim positioning above and confronting with the lower rim, so as to be shiftable along and rotatable about the vertical axis. A tested wheel is sandwiched between these upper and lower rims and is rotated together with the hollow rim support shaft for measuring dynamic balance of the tested wheel. The apparatus comprises a coupling shaft having an upper end connected integrally with the upper rim and a lower end formed with a plurality of engaging projections arrayed along an axial direction. This coupling shaft is inserted into or pulled out from the hollow rim support shaft. Claws are disposed inside the rim support shaft for selectively engaging with and disengaging from the engaging projections. A shift device shifts the claws between an engaging position and a disengaging position. A drive means is provided to drive this shift device. A rim width of the tested wheel to be held between upper and lower rims is regulated in accordance with an engaging position between the claws and the engaging projections. At least three abutting portions are provided on the outer surface of the coupling shaft, being spaced one another in a circumferential direction. The bearing is rigidly supported only in a detection direction of a displacement load detector.