A method for operating a motor vehicle, wherein the motor vehicle has a steering system for steering at least one wheel of the motor vehicle by means of a drive. In doing so, it is provided that a time span is determined for at least one countermeasure limiting a hazard to a vehicle occupant upon an at least partial failure of the steering system, within which time span the countermeasure deploys an effect, and that a state variable (T) influencing the operating capacity of the steering system is determined and extrapolated over time and a point in time (t.sub.1) is calculated in which the state variable (T) exceeds a limit value (T.sub.1), wherein the countermeasure is introduced when the point in time (t.sub.1) is less than the time span in the future.

An electric power steering system with a worm gear includes a worm shaft and a worm wheel, wherein an electric motor is associated with the worm shaft, which is connected to the worm shaft in a force-transmitting manner. A bearing element, arranged on the worm shaft at the end of the worm shaft facing away from the electric motor, is received in a guide bush, wherein the guide bush has, on its circumferential side, a passage opening. It is provided a pre-tensioning device comprising a spring-loaded actuator element extending through the passage opening of the guide bush and acting on the worm shaft in the direction of the worm wheel with a defined pre-tensioning force (K), wherein the pre-tensioning device comprises a limiting device which is adapted to limit a pivoting movement that displaces the worm wheel away from the worm shaft. Furthermore, it is proposed a method for the production of steering systems and a test system for performing the method.

A motor control unit that is connected to a motor release switch which includes FETs and is disposed between an inverter and a motor, including: a control section to detect an assist state of the inverter, to turn-ON or turn-OFF a control of the inverter based on a detection result and to detect whether abnormality is existed or not; a motor rotational speed detecting section to detect a motor rotational speed; an energy calculating section to calculate an energy based on the motor rotational speed; a judging section to turn-OFF all of the FETs of the motor release switch when the energy is within an area of safety operation; and a state detecting section to detect whether abnormality is existed or not based on information from an abnormality detecting section that detects abnormality of the sensors and the inverter, wherein the control section turns-ON the control of the inverter when the state detecting section does not detect abnormality and turns-OFF the control of the inverter when the state detecting section detects abnormality.

A rack assist electric power steering apparatus. Shock between a rotary support member and a housing is absorbed. Backlash and friction in the rotary support member are reduced. The length of a ball nut is minimized, and the rotary support member is supported by a portion in which the ball nut and a rack bar are coupled, so that noise is reduced.

Techniques for limiting electrical current provided to a motor for an electric power steering system are provided. A first estimated temperature of the motor is determined for a first time step. The first estimated temperature of the motor is filtered to produce a first filtered estimated temperature of the motor. A second estimated temperature of the motor is determined for a second time step subsequent to the first time step. The first filtered estimated temperature is compared with the second estimated temperature to determine whether the motor is heating or cooling. The filter is adjusted in response to determining whether the motor is heating or cooling. The second estimated temperature of the motor is filtered with the adjusted filter to produce a second filtered estimated temperature of the motor. A limit on electrical current provided to the motor is set using the second filtered estimated temperature.

A motor drive apparatus includes a control assembly that controls driving of a motor. The control assembly includes a controller that outputs a drive signal instructing a drive amount of the motor, a drive that supplies electric current, supplied from an external power supply, to the motor based on the drive signal output from the controller, a current detector that detects electric current flowing through the drive unit, and a first temperature detector that detects temperature of the drive unit. The control assembly calculates a heat storage amount stored in the control assembly at a predetermined cycle, and when the calculated heat storage amount is larger than a predetermined threshold, the control assembly outputs the drive signal that instructs a drive amount smaller than the drive amount at the time of calculation.

An electric power steering apparatus includes a control substrate that controls a poly-phase motor having a multi-system motor winding, including a temperature sensor that detects a substrate temperature of said control substrate; and a coil temperature estimating section that obtains coil calorific values of respective phases of said poly-phase motor and a substrate calorific value of said control substrate by a motor current of said phase, and estimates a coil temperature of said phase by said coil calorific value, said substrate calorific value and said substrate temperature based on a heat transfer phenomenon between said respective phases that is caused by a difference in temperature between coils of said respective phases and a heat transfer phenomenon between said coil and said control substrate.

A motor control device includes temperature detection elements that are mounted on a circuit board on which a first power conversion circuit and a second power conversion circuit are mounted and are arranged at a position between the first power conversion circuit and the second power conversion circuit.

Technical solutions are described for estimating machine parameters of a permanent magnet synchronous motor (PMSM) drive. An example method includes determining a region for estimating a machine parameter based on a motor velocity value and a motor current value. The method further includes, in response to the motor velocity value and the motor current value being in the region, estimating an error in estimated voltage command, and estimating the machine parameter using the error in estimated voltage command.

An electric power steering apparatus that enables more precise estimation of a coil temperature by considering a heat transfer phenomenon between a control substrate and a poly-phase coil in addition to a heat transfer phenomenon between respective phases of the coil. The apparatus includes a control substrate that controls a poly-phase motor, a temperature sensor that detects a substrate temperature of the control substrate and a coil temperature estimating section that estimates coil temperatures of respective phases of the poly-phase motor by a motor current of the phase and the substrate temperature based on a heat transfer phenomenon between the respective phases that is caused by a difference in temperature between coils of the respective phases and a heat transfer phenomenon between the coil and the control substrate.