| 摘要 |
A controllable differential having a clutch mechanism which transfers a predetermined amount of torque between a rotatable differential casing and a side gear when an initiating force is applied by an electronic actuator. The clutch mechanism comprises a cone clutch element having a frustoconical engagement surface and an insert having a complementary frustoconical engagement surface disposed between the side gear and the rotatable casing. The clutch mechanism further includes a pair of biasing elements which urge disengagement of the frustoconical engagement surfaces and resist axial movement of the cone clutch element and the insert. The cone clutch element and the side gear also include caroming portions having ramp surfaces which ride-up on each other and provide further axial separation forces when the clutch mechanism is actuated. Alternatively, a ball and ramp arrangement may be used to provide this axial separation. The clutch mechanism is actuated by an electromagnet which applies an initiating force to the cone clutch mechanism to initially move the cone clutch element when a predetermined relative rotational condition of the side gear is sensed. The application of the initiating force in combination with the interaction between the frustoconical engagement surfaces and between the caroming portions fully engages the clutch mechanism to transfer a predetermined controllable amount to torque. The present invention also provides a differential having a camming element disposed between a first clutch and a first side gear, the camming element has first and second caroming portions coupling the camming element to each of the first clutch and first side gear, adapted to couple them together. An electromagnet of variable strength urges the first clutch into engagement with an interior surface of the casing. Relative rotation between the caroming element and the first side gear induces axial separation therebetween, urging a second clutch attached to a second side gear in abutting communication with the first side gear, into engagement with another interior surface of the casing. The axial force exerted on the second clutch by the camming element through the first and second side gears may be a fixed multiple of the axial force acting between the first clutch and the camming element. The rotatable casing of the present invention may include a nonmagnetic portion attached thereto, about which the toroidal magnetic flux path of the adjacent electromagnet may be directed for actuating the clutch.
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