Dividing wall for primary pulley in belt-type continuously variable transmission

Abstract

The present invention relates to relates to an improvement of a dividing wall for a primary pulley in a belt-type continuously variable transmission. It is an object of the present invention to obtain a desired strength characteristic without performing a soft nitriding treatment and achieve cost reduction. A hydraulic pressure chamber is formed between the dividing wall and the movable sheave, and the dividing wall comprises a small-diameter annular disc portionextended from the central cylinder portion, which is attached to a rotational shaft, in a radial direction. In the small-diameter annular disc portion, a connecting portion which is connected to an intermediate body portionis a bent portionwhich is bent at substantially 90 [deg]. In a cross-section of an inner peripheral surface of the bent portion, the inner peripheral surface of the bent portionis constituted by an inner radius side arc-whose origin position is Oand curvature radius is R, an outer radius side arc-whose origin position is O, which is a different position from the origin position Oof the inner radius side arc-, and curvature radius is R, which is a different value from the curvature radius Rof the inner radius side arc-, and an intermediate portion-that the inner radius side arc-is smoothly connected to the outer radius side arc-. By adopting the above shape, when a load is applied to the dividing wall, a stress value at a concave surfacecan be reduced, and desired durability can be obtained without performing the soft nitriding treatment and achieve cost reduction.