Timepiece movement fitted with an electromagnetic transducer comprising at least one coil and a rotor formed of a central shaft, of two magnetic plates that are mounted on the central shaft and of a plurality of bipolar magnets which are axially polarized and mounted on at least one of the two magnetic plates, said at least one coil penetrating at least partially into a circular space which is defined by the rotor between its two magnetic plates and left free by this rotor. The central shaft comprises a pinion which engages with a wheel of the timepiece movement, this pinion being arranged between the two magnetic plates and said wheel being partially arranged between the two magnetic plates, in an angular sector of the circular space that is left free by the electromagnetic transducer, so as to engage with the pinion. Advantageously, said wheel has a roller that is almost or entirely non-conductive and a non-magnetic staff.

The present invention concerns a method of controlling a rotational speed of a rotor (3) of a direct current electric motor (1) comprising an inductor circuit (A, B) for rotating the rotor, which is configured to rotate continuously and is equipped with permanent magnets. The method comprises: measuring the rotational speed of the rotor; determining a time drift in the rotor rotation compared to a reference signal; defining N speed thresholds with at least one being a variable speed threshold depending on the determined time drift, the N speed thresholds defining N+1 rotational speed ranges for the rotor; determining in which one of the N+1 rotational speed ranges the determined rotational speed of the rotor is; and finally selecting an action relative to the control of the inductor circuit, based on the determined rotational speed range, for controlling the rotational speed of the rotor.

A timepiece movement includes a movement case, a drive mechanism, a time mechanism driven by the drive mechanism, a day mechanism, and a day adjustment mechanism. The day mechanism is driven by the time mechanism through a frictional engagement therebetween. Once a torque generated by the day adjustment mechanism overcomes the frictional engagement, the day mechanism is permitted to be driven by the day adjustment mechanism. Therefore, an indicated day of the timepiece movement can be adjusted without pulling out of a day adjustment knob or an actuating shaft of the day adjustment mechanism.

A method for measuring the medium frequency of a digital signal derived from a reference periodic signal generated by an electronic oscillator (quartz oscillator) forming a timepiece (2) which includes an analogue time display device and a continuous rotation electromechanical transducer (generator or continuous rotation motor) which is kinematically linked to this display device and wherein the medium rotational speed is regulated by a regulation device. The medium frequency of the digital signal is determined by a measurement device (70) without galvanic contact with the movement of the timepiece. The measurement method makes it possible to determine the rate of the timepiece and the precision of the electronic oscillator based on regulation impulses detected by a magnetic sensor (72) and over a measurement period limited to the duration of an inhibition cycle of periods of the reference periodic signal.

A method for measuring the medium frequency of a digital signal derived from a reference periodic signal generated by an electronic oscillator (quartz oscillator) forming a timepiece (2) which includes an analogue time display device and a continuous rotation electromechanical transducer (generator or continuous rotation motor) which is kinematically linked to this display device and wherein the medium rotational speed is regulated by a regulation device. The medium frequency of the digital signal is determined by a measurement device (70) without galvanic contact with the movement of the timepiece. The measurement method makes it possible to determine the rate of the timepiece and the precision of the electronic oscillator based on regulation impulses detected by a magnetic sensor (72) and over a measurement period limited to the duration of an inhibition cycle of periods of the reference periodic signal.

A method for determining an error in the angular position measurement of a timepiece motor having one or more phases, including: detecting (3) each instant (14) when the value of one of the back electromotive forces is zero, storing (4) a time corresponding to each detected instant, measuring (5) several time intervals between two instants (14) detected in the same revolution of the motor, comparing (6) the measured time intervals to reference time intervals to deduce the reference intervals to which they correspond, and determining (7) an angular position measurement error if the measured intervals do not correspond to the expected reference intervals. The invention also relates to a method for correcting the angular position measurement. Also, a determination and correction system for implementing the methods and a timepiece including such a system.

The present invention concerns a method of controlling a rotational speed of a rotor (3) of a direct current electric motor (1) comprising an inductor circuit (A, B) for rotating the rotor, which is configured to rotate continuously and is equipped with permanent magnets. The method comprises: measuring the rotational speed of the rotor; determining a time drift in the rotor rotation compared to a reference signal; defining N speed thresholds with at least one being a variable speed threshold depending on the determined time drift, the N speed thresholds defining N+1 rotational speed ranges for the rotor; determining in which one of the N+1 rotational speed ranges the determined rotational speed of the rotor is; and finally selecting an action relative to the control of the inductor circuit, based on the determined rotational speed range, for controlling the rotational speed of the rotor.

A DC motor including a continuous rotation rotor; a first inductor characterized by first parameters; a second inductor characterized by second parameters; a voltage supply unit; a measurement unit for detecting time instants when a first induced voltage in the first inductor equals a second induced voltage in the second inductor; and a control unit for controlling the application of drive voltage pulses to the inductors. The rotor faces first the second inductor before facing the first inductor when being rotated. At least one of the second parameters is selected different from a corresponding parameter of the first parameters such that a maximum induced voltage in the first inductor is greater than a maximum induced voltage in the second inductor. The control unit is arranged to trigger each of the drive voltage pulses after a detection of an equal induced voltage in the first and second inductors.

A DC motor including a continuous rotation rotor; a first inductor characterized by first parameters; a second inductor characterized by second parameters; a voltage supply unit; a measurement unit for detecting time instants when a first induced voltage in the first inductor equals a second induced voltage in the second inductor; and a control unit for controlling the application of drive voltage pulses to the inductors. The rotor faces first the second inductor before facing the first inductor when being rotated. At least one of the second parameters is selected different from a corresponding parameter of the first parameters such that a maximum induced voltage in the first inductor is greater than a maximum induced voltage in the second inductor. The control unit is arranged to trigger each of the drive voltage pulses after a detection of an equal induced voltage in the first and second inductors.

A continuously rotating electric motor includes a rotor provided with permanent magnets and a stator formed by two coils in which, when the rotor is rotating, two induced voltage signals (U.sub.B1 and U.sub.B2) are respectively generated, which signals have an electric phase shift where 590, preferably 30<<65. The control device includes a circuit for detecting intersection times (T.sub.C) at which values of the two induced voltage signals are substantially equal. The control device is arranged to generate electric driving pulses to rotate the rotor, which are respectively initiated at initiation times determined by respective intersection times, and such that the electric driving pulses can be applied to the two coils arranged in series. Preferably, the control device is arranged such that the initiation times of the electric driving pulses occur directly after detections of corresponding intersection times.