Abstract: Protrusions (260) for adjusting the cogging torque of a rotor (21) are formed on a stator (22) in a small-size power generator (20). Since the protrusions (260) are formed on an inner periphery of a rotor accommodation hole (230) within an angular range of ±45° around a magnetic flux direction of a first magnetic circuit (100) having a smaller magnetic reluctance at a rotation center of the rotor (21), the cogging torque can be effectively reduced. Accordingly, even when the size of components such as an oscillating weight and a power spring is reduced for making a thin timepiece, rotation startability of the rotor can be improved, thus improving power generation efficiency of the small-size power generator.

Abstract: Opposing concave structures formed in an end portion 22b of a stator yoke 22 and an end portion 23b of a magnetic core 23 are mated in a staggered manner and are joined. An upper projecting portion 22b-1 of the stator yoke 22 is fitted in a recessed portion formed on a lower projecting portion 23b-2 of the magnetic core 23, and the lower projecting portion 23b-2 of the magnetic core 23 is fitted in a recessed portion formed under the upper projecting portion 22b-1 of the stator yoke 22. In this state, the stator yoke 22 and the magnetic core 23 are fixedly fastened by a joint screw 24 and a tube 26. This structure makes it possible to reduce magnetic resistance in a magnetic circuit structure and to improve power-generating efficiency of a power-generating device using the structure.

Abstract: Protrusions (260) for adjusting the cogging torque of a rotor (21) are formed on a stator (22) in a small-size power generator (20). Since the protrusions (260) are formed on an inner periphery of a rotor accommodation hole (230) within an angular range of 45° around a magnetic flux direction of a first magnetic circuit (100) having a smaller magnetic reluctance at a rotation center of the rotor (21), the cogging torque can be effectively reduced. Accordingly, even when the size of components such as an oscillating weight and a power spring is reduced for making a thin timepiece, rotation startability of the rotor can be improved, thus improving power generation efficiency of the small-size power generator.

Abstract: An inside notch (37) serving as an adjusting section is provided for a magnetic balancing adjustment between stators (31 and 32) and a rotor (12). The inside notch acts to reduce cogging torque, thereby allowing the rotor to rotate using a slight torque. Therefore, the rotor can be more readily started without using a complicated structure, can be prevented from easily stopping due to an external disturbance, and can be made more reliable. In reducing the cogging torque, it is not necessary to reduce the number of magnetic flux lines by, for example, making a rotor magnet (12b) smaller, making it possible to maintain the efficiency with which electrical power is produced.

Abstract: In a power generator (20) including a rotor (21), a stator (magnetic core) (22) and a coil (23), a formula (1) including hysteresis loss coefficient kh, eddy-current loss coefficient ke, resistivity &rgr; (&OHgr;·m), frequency f (Hz) and maximum amplitude magnetic flux density Bm (T) is applied in setting plate thickness of the stator (22). Since the plate thickness (d) (m) of the stator (22) is set to the minimum iron loss plate thickness (d) obtained by the formula (1), the iron loss of the magnetic circuit of the power generator can be reduced, thereby improving efficiency of the power generator.

Abstract: Protrusions (260) for adjusting the cogging torque of a rotor (21) are formed on a stator (22) in a small-size power generator (20). Since the protrusions (260) are formed on an inner periphery of a rotor accommodation hole (230) within an angular range of ±45° around a magnetic flux direction of a first magnetic circuit (100) having a smaller magnetic reluctance at a rotation center of the rotor (21), the cogging torque can be effectively reduced. Accordingly, even when the size of components such as an oscillating weight and a power spring is reduced for making a thin timepiece, rotation startability of the rotor can be improved, thus improving power generation efficiency of the small-size power generator.

Abstract: Inner notches (225A, 226A) for adjusting the cogging torque of a rotor (21) are formed on a stator (22) in a small-size power generator (20). Since the inner notches (225A, 226A) are formed on an inner periphery of a rotor accommodation hole (230) within an angular range of ±45° around a magnetic flux direction of a first magnetic circuit (100) having a smaller magnetic reluctance at a rotation center of the rotor (21), the cogging torque can be effectively reduced. Accordingly, even when the size of components such as an oscillating weight and a power spring is reduced for making a thin timepiece, rotation startability of the rotor can be improved, thus improving power generation efficiency of the small-size power generator.

Abstract: In a power generator (20) including a rotor (21), a stator (magnetic core) (22) and a coil (23), a formula (1) including hysteresis loss coefficient kh, eddy-current loss coefficient ke, resistivity &rgr; (&OHgr;·m), frequency f (Hz) and maximum amplitude magnetic flux density Bm (T) is applied in setting plate thickness of the stator (22). Since the plate thickness (d) (m) of the stator (22) is set to the minimum iron loss plate thickness (d) obtained by the formula (1), the iron loss of the magnetic circuit of the power generator can be reduced, thereby improving efficiency of the power generator.

Abstract: Inner notches (225A, 226A) for adjusting the cogging torque of a rotor (21) are formed on a stator (22) in a small-size power generator (20). Since the inner notches (225A, 226A) are formed on an inner periphery of a rotor accommodation hole (230) within an angular range of ±45° around a magnetic flux direction of a first magnetic circuit (100) having a smaller magnetic reluctance at a rotation center of the rotor (21), the cogging torque can be effectively reduced. Accordingly, even when the size of components such as an oscillating weight and a power spring is reduced for making a thin timepiece, rotation startability of the rotor can be improved, thus improving power generation efficiency of the small-size power generator.

Abstract: A brushless DC motor, whose stator (10) is a combination of stator yokes (11, 16). a bobbin (14) on which a magnetic field coil (15) is wound and to which terminal pins are provided, and a base plate (20). The stator (10) is fixed to the base plate (20) by a protrusion (12c) provided on the bobbin (14) or by a flange (18a) formed on a bearing. The widths of magnetic poles (11a, 16a) of the stator, which are measured in the circumferential direction of the stator, are smaller than the width of one of the poles of a rotor magnet (5). Thereby, the position of a stable point is a maximum excitation torque position. Further, a magnetic pole sensing element (21) is provided at a place which is shifted in the circumferential direction from the middle position of one of the magnetic poles of the rotor magnet (5).

Abstract: A brushless DC motor, whose stator (10) is a combination of stator yokes (11, 16), a bobbin (14) on which a magnetic field coil (15) is wound and to which terminal pins are provided, and a base plate (20). The stator (10) is fixed to the base plate (20) by a protrusion (12c) provided on the bobbin (14) or by a flange (18a) formed on a bearing. The widths of magnetic poles (11a, 16a) of the stator, which are measured in the circumferential direction of the stator, are smaller than the width of one of the poles of a rotor magnet (5). Thereby, the position of a stable point is a maximum excitation torque position. Further, a magnetic pole sensing element (21) is provided at a place which is shifted in the circumferential direction from the middle position of one of the magnetic poles of the rotor magnet (5).

Abstract: In a radial gap type brushless DC motor having a motor structure for generating a starting torque and lowering rotational speed fluctuation by forming either one of a pair of upper and lower (right and left) claw poles to have a smaller interval in the circumferential direction with respect to the other claw pole, shifting the position of the upper or lower claw poles toward the rotating direction of the rotor from the middle position of the other claw pole and claw pole, and setting a ratio (a/p) of the claw pole width a and the pole pitch p, a ratio (b/a) of the claw pole width a and the claw pole width b, and a ratio (c/d) of the claw pole pitch c and the claw pole pitch d to fall in a prescribed range, a method for driving a motor forms the generated torque cycle of a cogging torque generated between a permanent magnet rotor (2) and a stator into large and small torque waves, and switches the current of a coil (12) at a high peak of absolute quantity or in the vicinity thereof among a plurality of positiv

Abstract: A brushless DC motor, whose stator (10) is a combination of stator yokes (11, 16), a bobbin (14) on which a magnetic field coil (15) is wound and to which terminal pins are provided, and a base plate (20). The stator (10) is fixed to the base plate (20) by a protrusion (12c) provided on the bobbin (14) or by a flange (18a) formed on a bearing. The widths of magnetic poles (11a, 16a) of the stator, which are measured in the circumferential direction of the stator, are smaller than the width of one of the poles of a rotor magnet (5). Thereby, the position of a stable point is a maximum excitation torque position. Further, a magnetic pole sensing element (21) is provided at a place which is shifted in the circumferential direction from the middle position of one of the magnetic poles of the rotor magnet (5).

Abstract: In a radial gap type brushless DC motor having a motor structure for generating an starting torque and lowering rotational speed fluctuation by forming either one of a pair of upper and lower (right and left) claw poles to have a smaller interval in the circumferential direction with respect to the other claw pole, shifting the position of the upper or lower claw poles toward the rotating direction of the rotor from the middle position of the other claw pole and claw pole, and setting a ratio (a/p) of the claw pole width a and the pole pitch p, a ratio (b/a) of the claw pole width a and the claw pole width b, and a ratio (c/d) of the claw pole pitch c and the claw pole pitch d to fall in a prescribed range, a method for driving a motor forms the generated torque cycle of a cogging torque generated between a permanent magnet rotor (2) and a stator into large and small torque waves, and switches the current of a coil (12) at a high peak of absolute quantity or in the vicinity thereof among a plurality of positi

Abstract: A shaped article composed of an at least biaxially orientated tetrafluoroethylene polymer of ultrahigh molecular weight, which has a draw ratio of at least 3.0, a specific gravity of at least 1.8 and an orientation release stress at 200.degree. C. of at least 5 Kg/cm.sup.2. The shaped article has excellent creep resistant and gas barrier properties, and can advantageously be utilized as a sealant, a lining material, a bearing pad, a sliding pad or the like. The shaped article may be produced by compressing a preformed sheet of a tetrafluoroethylene polymer at a temperature of from 170.degree. to 400.degree. C., under such conditions that plug flow of the polymer is produced, followed by cooling in the compressed state.