A synchronous belt drive system having: a synchronous belt with a tensile cord of high-modulus fiber such as glass, carbon, PBO, or aramid; a driver sprocket and at least one driven sprocket, at least one of which is an obround sprocket; and a tensioner having: a base having a cylindrical portion extending axially with a radially outer surface and a receiving portion, an eccentric arm pivotally engaged with the radially outer surface, a torsion spring disposed within the receiving portion, the torsion spring applying a biasing force to the eccentric arm, and a pulley journalled to the eccentric arm. Preferably, no one of the eccentric arm, pulley, or torsion spring is axially displaced along an axis A-A from the others. The obround sprocket has a toothed surface and at least one linear portion disposed between two arcuate portions having a constant radius, the linear portion having a predetermined length.

A strain wave gearing has a wave generator provided with a rigid plug and a wave bearing. The wave bearing is of a deep groove bearing type and is mounted on an elliptical outer circumferential surface of the rigid plug, whereby outer race and inner race thereof are flexed into an elliptical shape. Where D is a ball diameter of the balls, Ro is a raceway-surface radius of the outer race, Ri is a raceway-surface radius of the inner race, Ro/D is an outer-race conformity, and Ri/D is an inner-race conformity, the outer-race conformity Ro/D is greater than the inner-race conformity Ri/D. The friction torque of the wave bearing can be reduced while maintaining the practical service life thereof to be the same level as in a conventional one.

The motorized drive according to the invention application is configured to open and/or close a wing of a barrier such as a door, main door, gate or swing shutter, a wall or sliding partition or other sliding wing. The motorized drive comprises includes a motor and a first reduction unit through which the motor can open or close the wing. The reduction unit comprises includes a first and a second toothed profile engaging together, thus realizing a gear with a variable transmission ratio depending on the angular and/or linear position of at least one of the two toothed profiles. At least one of the first and of the second toothed profile forms at least one toothed section having a pitch profile which is substantially non-circular or not formed by a simple arc of a circle or a straight line.

A gearmotor includes a motor assembly and a gear assembly. The motor assembly includes a rotor and a rotor bearing. The rotor is rotatable about an axis. The rotor includes a rotor shaft. The rotor bearing rotatably supports the rotor shaft. The gear assembly includes an output shaft and a gear system. The output shaft is rotatable about the axis. The gear system is configured to transmit rotation from the rotor shaft to the output shaft. The gear system includes a deformable gear and a gear bearing. The gear bearing couples the rotor shaft to the deformable gear. The deformable gear defines a plurality of teeth. The deformable gear defines an interior space. The rotor bearing and the gear bearing are received within the interior space.

A synchronous drive is provided in which a non-circular rotor generates a fluctuating corrective torque to counteract a fluctuating load torque on a driven rotor. The angular orientation of the non-circular rotor can vary relative to the driven rotor so as to change the phase angle of the fluctuating corrective torque relative to the driving rotor. The arrangement may be applied in internal combustion engines with variable valve timing (VVT) systems, wherein the phase angle of a fluctuating load torque presented on a cam rotor, due to forces arising from actuation of intake and/or exhaust valves by the camshaft, varies relative to the crankshaft. The phase angle of the fluctuating corrective torque is also varied relative to the crankshaft to maintain phase relationship with the fluctuating load torque and thereby maintain reduced cam torsional vibrations and span tensions provided by the non-circular rotor during operation.

A synchronous belt drive system having: a synchronous belt with a tensile cord of high-modulus fiber such as glass, carbon, PBO, or aramid; a driver sprocket and at least one driven sprocket, at least one of which is an obround sprocket; and a tensioner having: a base having a cylindrical portion extending axially with a radially outer surface and a receiving portion, an eccentric arm pivotally engaged with the radially outer surface, a torsion spring disposed within the receiving portion, the torsion spring applying a biasing force to the eccentric arm, and a pulley journalled to the eccentric arm. Preferably, no one of the eccentric arm, pulley, or torsion spring is axially displaced along an axis A-A from the others. The obround sprocket has a toothed surface and at least one linear portion disposed between two arcuate portions having a constant radius, the linear portion having a predetermined length.

A synchronous drive is provided in which a non-circular rotor generates a fluctuating corrective torque to counteract a fluctuating load torque on a driven rotor. The angular orientation of the non-circular rotor can vary relative to the driven rotor so as to change the phase angle of the fluctuating corrective torque relative to the driving rotor. The arrangement may be applied in internal combustion engines with variable valve timing (VVT) systems, wherein the phase angle of a fluctuating load torque presented on a cam rotor, due to forces arising from actuation of intake and/or exhaust valves by the camshaft, varies relative to the crankshaft. The phase angle of the fluctuating corrective torque is also varied relative to the crankshaft to maintain phase relationship with the fluctuating load torque and thereby maintain reduced cam torsional vibrations and span tensions provided by the non-circular rotor during operation

An actuation mechanism for a valve comprises a first member having a generally spherical surface on a first side of a bisecting line and a generally ellipsoidal surface on a second side of the bisecting line. The first member is rotatable around a central point of the bisecting line. The valve has a second member with a truncated ellipsoidal surface on both sides of a bisecting line. The second member matingly engages the first member at the first member ellipsoidal surface. The valve also includes a longitudinal member coupled to the second member and a biasing member coupled to the longitudinal member. The first member is rotated around the central point from a first position to a second position to move the second member and the longitudinal member linearly. The biasing member returns the first member and second member to the first position upon release of the first member.

The invention relates to a harmonic pin ring drive with an outer gear ring toothing comprises a quantity of teeth which is greater by exact one than the quantity of teeth of an inner gear ring toothing. The invention further relates to a motor unit comprising such a harmonic pin ring drive and to an electrically assisted bicycle.

An apparatus for an actuating mechanism comprises a first member having a first axis; the first member has a generally spherical surface on a first half of the first axis and a generally ellipsoidal surface on a second half of the first axis. The first member is rotatable around a centerpoint of the first axis. A second member has a second axis and a generally ellipsoidal surface. The second member matingly engages the first member at the first member ellipsoidal surface and has a torsion spring coupled to the second member. The first member is actuated manually to move the second member. The torsion spring torque increases as the first member is rotated.