Manufacturing method of friction torque limiter

A manufacturing method of a torque limiter that includes an inner ring having a circular cross section, a spring member that is annular, and an outer ring, which have a common center axis, in which the spring member surrounds an outer peripheral surface of the inner ring, and the spring member and the outer ring are assembled so as to be relatively non-rotational by retaining means,

• a plurality of the spring members are disposed in series in an axial direction, each of the plurality of spring members including a base portion that is an annular thin plate, and a plurality of elastic pieces that extend toward an inner side in a radial direction, inclined in the axial direction, and that also are disposed at intervals in a peripheral direction, with tip end portions of the elastic pieces having abutting inner surfaces that abut the outer peripheral surface of the inner ring, and
• when rotational torque of a predetermined value or greater is applied between the inner ring and the outer ring, the inner ring and the outer ring rotate relative to each other against frictional force between the outer peripheral surface of the inner ring and the abutting inner surface of the spring members,
• the manufacturing method comprising:
• a press-fitting step of sequentially press-fitting the spring members to the inner ring one at a time;
• and
• an assembling step of, following the press-fitting step, assembling the inner ring to which the spring member is press-fit, with the outer ring, wherein
• in the press-fitting step, an amount of press-fitting of each of the plurality of spring members as to the inner ring is gradually reduced.

A torque limiter that includes an inner ring having a circular cross section, a spring member that is annular, and an outer ring, which have a common center axis, in which the spring member surrounds an outer peripheral surface of the inner ring, and the spring member and the outer ring are assembled so as to be relatively non-rotational by retaining means,

• the spring member includes a base portion that is an annular thin plate, and a plurality of elastic pieces that extend toward an inner side in a radial direction, inclined in an axial direction, and that also are disposed at intervals in a peripheral direction, with tip end portions of the elastic pieces having abutting inner surfaces that abut the outer peripheral surface of the inner ring, and
• when rotational torque of a predetermined value or greater is applied between the inner ring and the outer ring, the inner ring and the outer ring rotate relative to each other against frictional force between the outer peripheral surface of the inner ring and the abutting inner surface of the spring members, wherein
• the retaining means is made up of a retaining protrusion that protrudes toward an outer side in the radial direction from an outer peripheral surface of the base portion of the spring member and a retained protrusion that protrudes toward the inner side in the radial direction from an inner peripheral surface of the outer ring, and
• a base end of the elastic piece is connected to an inner peripheral surface of the base portion.