Conical surface friction type overrunning clutch

A conical surface friction type overrunning clutch, comprising:

• an inner ring, an outer ring, a first intermediate ring, a second intermediate ring, and an elastic pre-tightening member;
• wherein,
• the inner ring, the outer ring, the first intermediate ring and the second intermediate ring have a common rotation axis;
• the first intermediate ring and the second intermediate ring are both located between the inner ring and the outer ring;
• a boss is provided on a middle portion of the inner ring, and the first intermediate ring and the second intermediate ring are respectively arranged at two sides of the boss of the inner ring;
• the first intermediate ring and the second intermediate ring each cooperates with the outer ring via conical surfaces, to respectively form at least one first working friction pair and at least one second working friction pair which are both axially engageable and disengageable;
• and a first force amplifying transmission mechanism and a second force amplifying transmission mechanism are respectively formed between the first intermediate ring and the inner ring and between the second intermediate ring and the inner ring, and the first intermediate ring and the second intermediate ring are respectively connected to the inner ring via the first force amplifying transmission mechanism and the second force amplifying transmission mechanism;
• and
• each of the force amplifying transmission mechanisms is constituted by a structural shape directly formed on the respective intermediate ring directly engaging with a structural shape directly formed on the boss of the inner ring, and each of the structural shapes is an axial inclined wedge surface;
• the elastic pre-tightening member has one end arranged on the first intermediate ring or the second intermediate ring, to allow all the working friction pairs to maintain an elastic pressing force which meets a working requirement when the working friction pairs are not working;
• the first working friction pair and the second working friction pair have a common rotation axis, and two conical surfaces of each working friction pair that cooperate with each other have equal cone apex angles;
• for the cone apex angle of any one of the working friction pairs, the cone apex angle referred to as θ and a friction coefficient of the friction pair referred to as μ0 must satisfy a condition of 2 arctan(μ0)<θ≤180°, wherein arctan( ) in the formula represents arctangent function, and the condition is to ensure that self lock of the working friction pair will not occur;
• at least one of the force amplifying transmission mechanisms is configured to convert a relative rotation arc length between the respective intermediate ring and the inner ring or the outer ring which is connected to the respective force amplifying transmission mechanism to an axial relative displacement, and in a case that the relative rotation arc length is φ, and the generated axial relative displacement is λ, and the friction coefficient of the respective force amplifying transmission mechanism is μ1, a condition of arctan(dλ/dφ)>arctan(μ1) must be satisfied, wherein arctan( ) in the formula represents arctangent function, and d represents differential, and the condition is to ensure that self lock of the respective force amplifying transmission mechanism will not occur;
• and
• in a case that the first working friction pair and the second working friction pair are converted to a theoretically equivalent working friction pair, a tangential external component force in a direction of self lock occurred between the inner ring and the outer ring is F1, and a normal force generated on the equivalent working friction pair by an action of the respective force amplifying transmission mechanism is F2, an equivalent friction coefficient of the equivalent working friction pair is μ, and a design condition for the overrunning clutch to realize a maximum bearing capacity is dF1/dF2≤μ;
• and a design condition for the overrunning clutch to achieve overload slipping protection is dF1/dF2>μ, wherein d in the formula represents differential.