Centrifugal clutch

A vehicular drivetrain (10) comprising an engine (18), a change gear transmission (12) and a centrifugally operated master friction clutch (20) for coupling an output member (136) of said engine to a transmission input shaft (28), said centrifugally operated master friction clutch including a driving member assembly (60) fixedly rotatable with said engine output member and a driven member assembly (62) rotatable with said transmission input shaft, said drivetrain characterized by:

• said clutch comprising:
• a plurality of flyweights (110) carried by said driving member assembly for unitary rotation therewith and radial movement relative thereto;
• return members (114) urging said flyweights radially inwardly;
• wedging members (120) fixed to said flyweights for radial movement therewith, said wedging members received between opposed surfaces (124 and 126) of a relatively axially fixed reaction plate (125) and an axially movable plate (128), a first of said surfaces (126) defining a plurality of ramped portions (148) extending radially outwardly and axially toward the other of said surfaces whereby as said wedging members moves radially outwardly along said ramped portions said axially movable plate will be urged in an axial direction away from said reaction plate;
• an axially movable pressure plate (130) rotatable with said driving member assembly for applying a clamping force (CF) to frictionally engage a friction member (140/142) rotatable with said input shaft with a friction member (136A/104/130A) rotatable with said driving member, and
• a resilient member (132) axially interposed between said axially movable plate and said pressure plate for limiting the magnitude of said clamping force;
• said engine having a known idle speed;
• and
• said flyweight and return members configured such that said wedging members will be positioned radially inwardly of said ramped portion of said surface when said driving member assembly is rotating at a speed no greater than said idle speed.

A vehicular centrifugally operated master friction clutch (20) for coupling an output member (136) of an engine (18) to a transmission input shaft (28), said clutch including a driving member assembly (60) fixedly rotatable with said engine output member and a driven member assembly (62) rotatable with said transmission input shaft, said clutch comprising:

• a plurality of flyweights (110) carried by said driving member assembly for unitary rotation therewith and radial movement relative thereto;
• return members (114) urging said flyweights radially inwardly;
• actuation members carried by said flyweights for movement therewith, said actuation members acting on an axially movable plate (128) whereby as said flyweights move radially outwardly said axially movable plate will be urged in an axial direction away from an axially fixed reaction plate;
• an axially movable pressure plate (130) rotatable with said driving member assembly for applying a clamping force (CF) to frictionally engage a friction member (140/142) rotatable with said input shaft with a friction member (136A/104/130A) rotatable with said driving member assembly, and
• a resilient member (132) axially interposed between said axially movable plate and said pressure plate for limiting the magnitude of said clamping force.

A vehicular centrifugally operated master friction clutch (20) for coupling an output member (136) of an engine (18) to a transmission input shaft (28), said clutch including a driving member assembly (60) fixedly rotatable with said engine output member and a driven member assembly (62) rotatable with said transmission input shaft, said clutch comprising:

• a plurality of flyweights (110) carried by said driving member assembly for unitary rotation therewith and radial movement relative thereto;
• return members (114) urging said flyweights radially inwardly;
• wedging members (120) fixed to said flyweights for radial movement therewith, said wedging members received between opposed surfaces (124 and 126) of a relatively axially fixed reaction plate (125) and an axially movable plate (128), a first of said surfaces (126) defining a first portion (148), said first portion being ramped and extending radially outwardly and axially toward the other of said surfaces whereby as said wedging member moves radially outwardly along said first portion said axially movable plate will be urged in an axial direction away from said reaction plate, said first of said surfaces (126) also defining a second portion (150) located radially outwardly of said first portion (148) and extending axially towards said other surface (124) by a lesser degree then said first portion whereby movement of said wedging member radially outwardly along said second portion (150) will have a lessor tendency to increase or decrease urging of said axially movable plate in said axial direction than will movement of said wedging member radially along said first portion;
• an axially movable pressure plate (130) rotatable with said driving member assembly for applying a clamping force (CF) to frictionally engage a friction member (140/142) rotatable with said input shaft with a friction member (136A/104/130A) rotatable with said driving member assembly, and
• a resilient member (132) axially interposed between said axially movable plate and said pressure plate for limiting the magnitude of said clamping force.