GB1496159A - Device for converting rotary motion to axial motion and a method of applying the device for truing polishing or calibrating a cylindrical body - Google Patents

Abstract

1496159 Rolling apparatus; burnishing H G OLRIK 17 Dec 1974 [17 Dec 1973 25 Feb 1974 16 Sept 1974] 54542/74 Headings B3M and B3X [Also in Division F2] A method of straightening, burnishing or "calibrating" a cylindrical shaft, by means of a device otherwise used for converting rotary into linear motion. In this device, Figs. 1, 2, a friction drive unit 9 employs rolling bearings 47, 49 and 63, 65, as friction members, the inner diameter of each inner race 55, 57, 71, 73 being larger than the surface diameter of a shaft 17, against which they are eccentrically held under mutually balancing radial forces, and the rolling axis of each bearing being tilted relatively to the axis of the shaft 17, such that, under conditions of relative rotation between the rolling assembly and the shaft, each inner race rolls upon a helical path around the shaft, thereby imparting a relative linear motion, and the rolling bearings, supported in separate groups within a common cage member 23, are also provided with clamping means arranged in such a manner that the radial forces exerted on the shaft become increased in response to an increase in the axial load on the shaft. The pairs of rolling bearings may be secured within recesses in jaw members 37, 39, which are keyed by bolts 25, 29, to the rotatable cage 23, and the jaws 37, 39 are urged inwardly by a clamping means consisting of a winding of piano wire 81. When a load is applied to the shaft 17 in the axial direction marked K, one jaw member 37 abuts an end stop 83, while the other jaw member 39, frictionally drawn into a relative axial displacement, is arrested only by tensional forces in the clamping wire 81, causing the radial forces exerted on the jaw members 37, 39 to become increased. In other embodiments, the clamping means may consist of a cam or lever construction, with the effect of providing increased radial forces in response to an axial shaft load. The embodiment of Fig. 1 comprises an assembly of a friction unit 9 with a motor having a stator 3, a rotor 5, and a hollow motor shaft 7. Each inner race 55, &c. may be formed with an inwardly convex cross-section, adapted to contact the shaft along a line for the entire width of the race, thereby minimizing local stresses in the shaft surface. Alternatively, the race may have ridges projecting inwardly, to increase the shaft surface stresses. The device may thus be adapted for straightening shafts without surface changes, or for "calibrating" shafts by producing controlled surface deformation. In further embodiments, one or more of the bearing races may be inclined at a helix angle which differs from that of the remaining bearing races, thereby producing a burnishing action upon the shaft surface during relative rotation.