Bearing preloading device

A bearing preloading device comprising:

• at least one compression coil spring configured to axially push a bearing race;
• and
• a threaded portion into which the compression coil spring can be axially screwed so as to be threadedly engaged in the threaded portion,
• wherein the threaded portion is defined in one of the bearing race and a separate member from the bearing race, the separate member being axially opposed to the bearing race,
• wherein the one of the bearing race and the separate member has an inner periphery defining an axially recessed hole, and comprising the threaded portion, connected to a bottom surface of the hole, and a shallow hole portion connected to an edge of the hole,
• wherein an inner diameter of the shallow hole portion is larger than an inner diameter of the threaded portion,
• wherein the shallow hole portion is concentric with the threaded portion, and the inner diameter of the shallow hole portion is larger than an outer diameter of the compression coil spring,
• wherein the compression coil spring has a natural length such that, when the compression spring is not compressed, the compression coil spring axially protrudes from the shallow hole portion, and
• wherein an axial length of the shallow hole portion is set such that the compression coil spring can be compressed until the compression coil spring is entirely received in the hole.