Patent ID: 9395254
Filing Date: 2016-07-19
CPC Classification: F16D,G01L

Claim Text:
1. A transmission torque estimation unit for a driving force transmission apparatus, the driving force transmission apparatus including: a cylindrical outer rotary member; an inner rotary member arranged inside the outer rotary member so as to be coaxial with the outer rotary member and rotatable relative to the outer rotary member; a main clutch that transmits a torque between the outer rotary member and the inner rotary member; an electromagnetic clutch device including a pilot clutch that is able to transmit a torque of the outer rotary member by attracting an armature with a magnetic force corresponding to a control signal; and a cam mechanism that is arranged between the main clutch and the pilot clutch, and that moves a movable cam member with respect to a support cam member in an axial direction by converting, into an axial pressing force, a torque based on a difference in rotational speed between rotation of the inner rotary member and rotation of the outer rotary member, which is transmitted via the pilot clutch, to press the main clutch, wherein the main clutch includes inner main clutch discs that are restrained from rotating relative to the inner rotary member but allowed to move in the axial direction, and outer main clutch discs that are restrained from rotating relative to the outer rotary member but allowed to move in the axial direction, and the pilot clutch includes an inner pilot clutch disc that is restrained from rotating relative to the support cam member but allowed to move in the axial direction, and an outer pilot clutch discs that are restrained from rotating relative to the outer rotary member but allowed to move in the axial direction, the transmission torque estimation unit estimating a torque transmittable between the outer rotary member and the inner rotary member with respect to the control signal based on: