Electric parking brake devices are configured such that a parking lever is driven by an electric actuator. The electric actuator is provided with: an electric motor drivable in a forward/reverse direction and operationally controlled by a motor control unit according to rotational loads; a conversion mechanism capable of converting a rotational motion into a linear motion, moving the parking lever from a return position toward an operating position through forward rotation of the electric motor, and moving the parking lever from the operating position toward the return position through the reverse rotation of the electric motor; and a load applying mechanism (a stopper and a disc spring assembly) for applying a predetermined rotational load to the electric motor by driving a constituent member of the conversion mechanism after the parking lever is moved from the operating position to the return position through the reverse rotation of the electric motor.

A system and method of accurately evaluating the performance of a vehicle device having a friction component, including a brake disc, a clutch disc, or the like, may be achieved by predicting the accurate friction coefficient of the friction component in consideration of changes in the temperature, rotation speed, and hydraulic pressure of the friction component, and determining the operating torque of the vehicle device or system having the friction component through reflecting the predicted friction coefficient, during the performance evaluation simulation process of the vehicle device including the friction component.

A system and method of accurately evaluating the performance of a vehicle device having a friction component, including a brake disc, a clutch disc, or the like, may be achieved by predicting the accurate friction coefficient of the friction component in consideration of changes in the temperature, rotation speed, and hydraulic pressure of the friction component, and determining the operating torque of the vehicle device or system having the friction component through reflecting the predicted friction coefficient, during the performance evaluation simulation process of the vehicle device including the friction component.

Disclosed is an electronic parking brake system including an electronic parking brake provided to provide a clamping force necessary for parking a vehicle by a motor, a warning unit provided to warn a failure of the electronic parking brake, a current sensor provided to detect a current of the motor, and a controller electrically connected to the current sensor, wherein the controller determines whether a clamping force is generated depending on the motor current in a parking operation, counts a clamping force non-generation time when the clamping force is not generated, and warns a suspected failure of the electronic parking brake through the warning unit when the clamping force non-generation time elapses a preliminary failure detection time set shorter than a failure detection time of the electronic parking brake.

Disclosed is an electronic parking brake system including an electronic parking brake provided to provide a clamping force necessary for parking a vehicle by a motor, a warning unit provided to warn a failure of the electronic parking brake, a current sensor provided to detect a current of the motor, and a controller electrically connected to the current sensor, wherein the controller determines whether a clamping force is generated depending on the motor current in a parking operation, counts a clamping force non-generation time when the clamping force is not generated, and warns a suspected failure of the electronic parking brake through the warning unit when the clamping force non-generation time elapses a preliminary failure detection time set shorter than a failure detection time of the electronic parking brake.

A wear volume estimation device estimates a wear volume of a brake pad of a vehicle. A wear volume function expresses the wear volume as a function of a vehicle speed, a brake pressure, and a brake duration. The wear volume estimation device calculates the wear volume by using the wear volume function. Moreover, the wear volume estimation device estimates a temperature of a contact surface of the brake pad that comes in contact with a brake rotor, and updates temperature history information indicating at least a temperature history of the contact surface based on the temperature of the contact surface. The wear volume estimation device variably sets the wear volume function according to the temperature history of the contact surface indicated by the temperature history information acquired at a time of previous braking.

A wear volume estimation device estimates a wear volume of a brake pad of a vehicle. A wear volume function expresses the wear volume as a function of a vehicle speed, a brake pressure, and a brake duration. The wear volume estimation device calculates the wear volume by using the wear volume function. Moreover, the wear volume estimation device estimates a temperature of a contact surface of the brake pad that comes in contact with a brake rotor, and updates temperature history information indicating at least a temperature history of the contact surface based on the temperature of the contact surface. The wear volume estimation device variably sets the wear volume function according to the temperature history of the contact surface indicated by the temperature history information acquired at a time of previous braking.

Methods and devices for monitoring a drive train for a wind turbine utilize an elastic coupling. The drive train comprises a rotor shaft configured to be driven by a rotor about a main axis, a support structure including a bearing housing surrounding at least one bearing and supporting the rotor shaft for rotation about the main axis to constrain other movements of the rotor shaft. A gearbox input shaft and housing supports the gearbox input shaft for rotation while constraining other movements of the gearbox input shaft. The gearbox input shaft is coupled to the rotor shaft by an elastic coupling that includes a first coupling part rigidly connected with the rotor shaft, a second coupling part rigidly connected with the gearbox input shaft, and elastic elements positioned between the first and the second coupling part to provide a single joint between the rotor shaft and the gearbox input shaft.

Methods and devices for monitoring a drive train for a wind turbine utilize an elastic coupling. The drive train comprises a rotor shaft configured to be driven by a rotor about a main axis, a support structure including a bearing housing surrounding at least one bearing and supporting the rotor shaft for rotation about the main axis to constrain other movements of the rotor shaft. A gearbox input shaft and housing supports the gearbox input shaft for rotation while constraining other movements of the gearbox input shaft. The gearbox input shaft is coupled to the rotor shaft by an elastic coupling that includes a first coupling part rigidly connected with the rotor shaft, a second coupling part rigidly connected with the gearbox input shaft, and elastic elements positioned between the first and the second coupling part to provide a single joint between the rotor shaft and the gearbox input shaft.

Improved maneuverability, improved followability towards a target braking force and enhanced brake feeling when a low braking force is being effected may be achieved. A brake controller unit may include a clearance estimator which may be configured to use a rotational angle θ of a motor to estimate a clearance, inclusive of negative values, between a frictional material and a brake. A target braking force F.sub.r may be compared with a switch-determining braking force F.sub.rsw, so that clearance control based on a target clearance C.sub.r may be performed when the frictional material is in approximate-contact state corresponding to the target braking force F.sub.r being low, and so that braking force control may be performed when it is equal to or greater than the switch-determining braking force F.sub.rsw.