A belt-tensioning device includes an electric machine having a drive belt pulley, which is driven about a drive axis, and a further drive belt pulley, where an endless belt wraps around the drive belt pulleys. The device has a housing in which a first and a second spring arm are mounted, in each of which spring arms a tension roller having axes of rotation which are parallel to the drive axis is rotatably mounted. The spring arms are supported against one another and press the endless belt together via the tension rollers in the region of the drive belt pulley. A first and a second further spring arm are provided adjacent to the spring arms which are adjustable by an adjustment element such that the spring forces of the further spring arms either do or do not support the spring forces of the spring arms acting on the endless belt.

An electric vehicle comprises a drive belt mounted about a motor output and about a drive wheel. The drive belt is driven by an output torque and experiences the output torque in a first torque direction and in a second torque direction. A belt tensioner comprises a tension pulley in contact with the drive belt, and a tensioning mechanism configured to displace the tension pulley in a first direction against the drive belt to tension the drive belt upon the drive belt experiencing the output torque in the first torque direction. The tensioning mechanism is configured to allow tension in the drive belt to displace the tension pulley in a second direction opposite to the first direction upon the drive belt experiencing the output torque in the second torque direction.

A yard maintenance device having a working assembly selectively rotatable based on operation of an engine of the device may include a belt drive system. The belt drive system may include at least one driven pulley operably coupled to the working assembly, a drive shaft operably coupled to the engine, a drive belt configured to selectively couple the drive shaft to the at least one driven pulley, a tension adjustment assembly, and a control unit. The tension adjustment assembly may be configured to operably couple to at least one component of the belt drive system to adjust a position thereof to modify tension of the drive belt. The control unit may be configured to provide electronic control of the tension adjustment assembly.

A belt drive system includes a drive sheave and a driven sheave. A drive motor turns the drive sheave when the drive motor is activated. A drive belt is connected to the drive sheave and the driven sheave so that the driven sheave is turned when the drive motor is activated. The drive motor is mounted upon a shuttle and the shuttle is slidingly mounted on a base. A drive system moves the shuttle when the adjustment motor is activated so that a position of the drive sheave relative to the driven sheave may be adjusted so as to increase a tension in the drive belt. A controller activates the adjustment motor when slippage of the drive belt on either the drive sheave or the driven sheave is detected.

An automatic tensioning apparatus is provided that includes a tensioning drive unit having: a longitudinally extending stationary base frame with a plurality of guides extending between a lower portion and an upper portion, and a plurality of rotatable feed wheels axially secured at the lower portion, as well as a translatable drive frame slidably coupled to the plurality of guides with a drive assembly coupled to the drive frame, the drive assembly including a drive motor and a tensile member interface for engaging and rotationally translating a tensile member. The tensioning drive unit further including a plurality of drive frame actuators actuatable to move the drive frame between a bottom frame position and a top frame position, as well as a sensor for at least indirectly sensing the position of the drive frame along a longitudinal base frame axis.

A tensioner assembly for tensioning a belt including a moveable arm, a first tensioner pulley mounted to the moveable arm, and a second tensioner pulley mounted to the moveable arm. In a first position of the moveable arm corresponding to a forward drive configuration, the first tensioner pulley is positioned in contact with the belt while the second tensioner pulley is spaced apart from the belt. In a second position of the moveable arm corresponding to a reverse drive configuration, the second tensioner pulley is positioned in contact with the belt while the first tensioner pulley is spaced apart from the belt.

The disclosure relates to a method for detecting belt slip of a belt drive driving a generator of an internal combustion engine, said belt drive having a belt tensioner that can be adjusted in operation and adjusts the pre-tensioning force of the belt according to the detected belt slip. According to said method, the rotational speed profile of the crankshaft is recorded during an angular window of the crankshaft of m.Math.360 degrees and an average value of the crankshaft rotational speed is formed from said rotational speed profile; temporally independently from the recording of the rotational speed profile of the crankshaft, the rotational speed course of the generator shaft is recorded during an angular window of the generator shaft of n.Math.u.sup.−1.Math.360 degrees and an average value of the generator shaft rotational speed is formed from said rotational speed profile.

The invention relates to a belt-tensioning device comprising a tensioning device for generating a force for tensioning a belt in a belt drive; a measuring device for measuring a belt tension or a measurement variable corresponding to the belt tension; and an adjustment device for adjusting the force generated by the tensioning device based on signals of the measuring device.

A pressure regulator is in fluid communication with a supply inlet of a hydraulic tensioner to actively control fluid to the inlet of the hydraulic tensioner. By actively controlling the pressure regulator based on engine conditions and thus the oil pressure being fed to the hydraulic tensioner, the oil pressure to the hydraulic tensioner may be reduced at low engine speeds, increasing the efficiency of the timing system, or allowing full oil pressure at high engine speeds and low engine temperature.

A belt-tensioning device includes an electric machine having a drive belt pulley, which is driven about a drive axis, and a further drive belt pulley, where an endless belt wraps around the drive belt pulleys. The device has a housing in which a first and a second spring arm are mounted, in each of which spring arms a tension roller having axes of rotation which are parallel to the drive axis is rotatably mounted. The spring arms are supported against one another and press the endless belt together via the tension rollers in the region of the drive belt pulley. A first and a second further spring arm are provided adjacent to the spring arms which are adjustable by an adjustment element such that the spring forces of the further spring arms either do or do not support the spring forces of the spring arms acting on the endless belt.