Abstract: The driven pulley is part of a continuously-variable transmission (CVT). The driven pulley comprises two coaxially-disposed sheaves defining between them a belt-receiving groove. It also has at least two axisymmetric ramp surfaces attached to one of the sheaves and at least two axisymmetric followers attached to the other sheave, each ramp surface being engageable by a corresponding one of the followers. At least some of the ramp surfaces are provided on corresponding ramp holders that are independent from the sheaves. A method of modifying the settings of a driven pulley and a method of assembling a driven pulley also disclosed.
Abstract: A method of managing a transmission ratio with an assisted CVT with a governed engine to emulate a hydrostatic transmission and prevent a drivebelt abuse is provided, the method comprising: providing a reference power source rotational speed, using the assisted CVT to transmit rotatable motion between a power source and a drive mechanism, managing a torque of the power source to maintain a substantially even rotational speed upon a power source load variation and modulating a transmission ratio of the assisted CVT to change the rotational speed of the drive mechanism. A system and a vehicle having such a drivebelt abuse preventing mechanism is also provided.
Type:
Grant
Filed:
May 13, 2011
Date of Patent:
April 1, 2014
Assignee:
CVTech Inc.
Inventors:
Hubert Roberge, David Levasseur, Francois Brind'Amour
Abstract: Is provided herein a torque-limiting electronically controlled CVT comprising a drive portion having a drive pulley including two opposed sheaves adapted to be actuated with an electric motor to set a transmission ratio between an engine and a ground contacting rotating member of a vehicle, an input module adapted to receive a signal indicative of whether a ground-contacting rotating member is airborne, a processing module adapted to determine a desired CVT ratio, and an output module adapted to actuate the electric motor to obtain the desired CVT ratio to match the circumferential velocity of the vehicle's airborne ground-contacting rotating member with the speed of the vehicle in order to limit a mechanical peak torque sustained by a drive system of the vehicle. Also provided hereby is a vehicle equipped with the CVT, a kit including such a CVT and a method of managing the CVT to limit the mechanical peak torque sustained by a drive train of a vehicle.
Type:
Grant
Filed:
December 22, 2010
Date of Patent:
March 25, 2014
Assignee:
CVTech Inc.
Inventors:
Hubert Roberge, David Levasseur, Christian Mercier
Abstract: The driving pulley has a fully clutched mode of operation where a drivebelt and a driveshaft are coupled together in a torque transmitting engagement and also has an unclutched mode of operation where there is substantially no torque transmitting engagement between the drive belt and the driveshaft. The driving pulley comprises at least one transitional clutch spring that is in a first position when the driving pulley is in the unclutched mode of operation and that is in a second position when the driving pulley is in the fully clutched mode of operation. The at least one transitional clutch spring remains substantially in its second position regardless of the relative axial distance between the sheaves when the driving pulley is in the fully clutched mode of operation. A method of operating a driving pulley is also disclosed. The proposed concept provides a smoother engagement during the transition from the unclutched mode to the fully clutched mode.