Patent ID: 11125306

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 portion 32 extended from the central cylinder portion 30, which is attached to a rotational shaft, in a radial direction. In the small-diameter annular disc portion 32, a connecting portion which is connected to an intermediate body portion 34 is a bent portion 38 which is bent at substantially 90 [deg]. In a cross-section of an inner peripheral surface of the bent portion 38, the inner peripheral surface of the bent portion 38 is constituted by an inner radius side arc 40-1 whose origin position is O1 and curvature radius is R1, an outer radius side arc 40-2 whose origin position is O2, which is a different position from the origin position O1 of the inner radius side arc 40-1, and curvature radius is R2, which is a different value from the curvature radius R1 of the inner radius side arc 40-1, and an intermediate portion 40-3 that the inner radius side arc 40-1 is smoothly connected to the outer radius side arc 40-2. By adopting the above shape, when a load is applied to the dividing wall, a stress value at a concave surface 40 can be reduced, and desired durability can be obtained without performing the soft nitriding treatment and achieve cost reduction.