Abstract: Rotational control apparatus in the forms of fan clutches (A, A') are shown including an eddy current drive (224). Specifically, the eddy current drive (224) includes a plurality of permanent magnets (226) mounted circumferentially spaced and with alternating polarity by a holder (228) to the input or output of the clutch (A, A') and a magnetically conductive ring (242) mounted to the other of the input or output of the clutch (A, A'). Thus, the output portion and the fan blades mounted thereto are driven at engine speeds when the clutch (A, A') is air actuated and are driven at a rotational speed less than engine speed by the eddy current drive (224) when the clutch (A, A') is not air actuated and without separate controls for the eddy current drive (224). A housing (62) comprises the output portion of the clutch (A) which is rotatably mounted by a bearing (58) to the hub portion (24) of a friction disc (28) which comprises the input portion of the clutch (A).

Abstract: Rotational control apparatus in the preferred forms of fan clutches (A) are shown including an eddy current drive (224). Specifically, the eddy current drive (224) includes a plurality of permanent magnets (226) mounted circumferentially spaced and with alternating polarity by a holder (228) to a radially extending surface (232) of a housing (62) rotatably mounted by a bearing (58) to the hub portion (24) of a friction disc (28). A magnetically conductive ring (242) is mounted on the opposite axial side of the friction disc (28) than the surface (34) engaged by a friction ring (86, 252) which is rotatably fixed but axially displaceable relative to the housing (62). In the embodiments shown, the friction ring (86, 252) is biased in a disengaged condition from the friction disc (28) by springs (138, 256) and is moved to an engaged condition by a fluid actuated piston (80).

Abstract: Rotational control apparatus in the preferred forms of fan clutches (A, A') are shown including an eddy current drive (224). Specifically, the eddy current drive (224) includes a plurality of permanent magnets (226) mounted circumferentially spaced and with alternating polarity by a holder (228) to the input of the clutch (A, A') and a magnetically conductive ring (242) mounted to the output of the clutch (A, A'). Thus, the output portion and the fan blades mounted thereto are driven at engine speeds when the clutch (A, A') is air actuated and are driven at a rotational speed less than engine speed by the eddy current drive (224) when the clutch (A, A') is not air actuated and without separate controls for the eddy current drive (224). In preferred forms, a housing (62) comprises the output portion of the clutch (A) which is rotatably mounted by a bearing (58) to the hub portion (24) of a friction disc (28) which comprises the input portion of the clutch (A).

Abstract: Rotational control apparatus in the form of fan clutches (C) are disclosed including a first, friction disc portion (12) splined on a hub (20) and rotatably mounted on a shaft (24). The friction disc portion (12) is reciprocal between a first position rotatably related to the facing (52) of a sheave (50) rotatably mounted on the hub (20) and a second position rotatably independent of the sheave (50). A second friction disc portion (212) is splined on the hub (20) and is reciprocal between a first position rotatably related to the facing (252) of a second sheave (250) rotatably mounted on the hub (20) and rotating at a different rotational speed than sheave (50). By selective engagement of the friction disc portions (12, 212), the hub (20) will be rotated on the shaft (24) at either the rotational speed of the first sheave (50) or the second sheave (250). In another form, a second, friction disc portion (112) is rotatably mounted on a reciprocal piston (100) and rotatable relative to the hub (20).

Abstract: A rotational control apparatus in the preferred form of a fan clutch is disclosed including a friction disc portion slidably mounted and rotationally related by splines on a hub in turn rotatably mounted on a fixed shaft. The splines are formed on a radially outermost portion of the hub. A washer abuts with a shoulder formed in the hub at the intersection of a radially reduced portion with the radially outermost portion and with a retainer on the free end of the radially reduced portion sandwiches a spring in a compressed condition on the reduced portion. In an assembled relation, the friction disc portion abuts with the washer such that the spring biases the friction disc portion. The friction disc portion may be slid from the hub without removal of the hub from the shaft and with the spring retained on the hub by the washer. Both sides of the friction disc portion taper together such that the thickness therebetween decreases with the radial spacing from the rotational axis.