US Patent 7648435 Belt-type continuously variable transmission

A belt-type continuously variable transmission (15) includes a primary sheave (29) having a pair of first clamp surfaces (37a, 37b), a secondary sheave (30) having a pair of second clamp surfaces (51a, 51b), and a belt (31) endlessly wound between both the sheaves (29, 30). The belt (31) has contact surfaces (58a, 58b) clamped between the first clamp surfaces (37a, 37b) and between the second clamp surfaces (51a, 51b). Powder (64) having infusibility as a friction enhancing material is held on at least one of the first clamp surfaces (37a, 37b) of the primary sheave (29), the second clamp surfaces (51a, 51b) of the secondary sheave (30), and the contact surfaces (58a, 58b) of the belt (31).