Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2001-08-30
2004-03-02
Waks, Joseph (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S191000
Reexamination Certificate
active
06700268
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a rotational electric machine with an effective magnetic flux density variable in accordance with the rotational speed and a vehicle loaded therewith.
Induced electromotive force of a rotational electric machine, especially of a permanent-magnet type rotational electric machine mounted on a vehicle such as a hybrid car or an electric car, is determined on the basis of a constant magnetic flux density generated by permanent magnets disposed in a rotor and a rotational angular velocity of the rotational electric machine. That is, when the rotational angular velocity of the rotational electric machine increases, the induced electromotive force of the rotational electric machine increases in proportion to the rotational angular velocity. Hence, the permanent-magnet type rotational electric machine was able to obtain high torque power but was hardly operated in a high rotation region because the variable rotational velocity range of the machine was narrow. In the past, therefore, the high rotation region was widened by field weakening control.
Further, the conventional rotational electric machine was designed in accordance with the rotation region. Hence, when both low rotation region and high rotation region were required, rotational electric machines prepared to satisfy the regions respectively were used as described in JP-A-9-132042. Alternatively, both the drive mode and electric power generation mode were provided in one rotational electric machine so that one mode could be selected from the two modes as described in JP-A-7-298696.
SUMMARY OF THE INVENTION
The field weakening control in the background art was performed by a field weakening control current flowing in the windings of a stator. It was however necessary to raise the field weakening control current in accordance with the induced electromotive force which rose in proportion to the rotational angular velocity. Hence, heat generated in the stator windings increased. Hence, there was the possibility that lowering of efficiency in the rotational electric machine, demagnetization of permanent magnets owing to heating beyond cooling performance might occur in a high rotation region. If a plurality of rotational electric machines were prepared to satisfy the respective rotation regions, an electric power converter and a control unit were required for driving each of the rotational electric machines. This caused complication of system configuration and cost rise.
A typical object of the present invention is to provide a rotational electric machine in which high torque characteristic can be obtained in a low rotation region whereas high output power generation characteristic can be obtained in a high rotation region, and a vehicle loaded with the rotational electric machine.
Another typical object of the present invention is to provide a rotational electric machine in which high torque characteristic can be obtained in a low rotation region whereas high power generation characteristic can be obtained in a high rotation region and in which mechanical reliability can be improved, and a vehicle loaded with the rotational electric machine.
The present invention is basically characterized in that high torque characteristic and high power generation characteristic are obtained in a low rotation region and in a high rotation region respectively by mechanical control, that is, by controlling effective magnetic flux through dividing a rotor into two rotor portions. Specifically, a rotor having different-polarity field magnets arranged alternately in a rotational direction is divided into two axially separate portions. The axial position of one of the two rotor portions is changed relative to that of the other in accordance with a direction of torque of the rotor or the phase of synthesized magnetic poles of the field magnets is changed relative to that of magnetic poles of the other rotor portion in accordance with a direction of torque of the rotor. As a result, in the present invention, field weakening control can be performed even in the case where the stator windings are not supplied with any current. Moreover, according to the present invention, one of the two separate rotor portions is supported from axially opposite sides by a support mechanism to thereby relax the axially moving force of the one rotor portion.
Typical aspects of the present invention are as follows.
A rotational electric machine comprising: a stator having windings; and a split rotor rotatably disposed on an inner circumferential side of the stator through an air gap and axially divided into two rotor portions, the rotor portions having different-polarity field magnets disposed alternately in a rotational direction; one of the rotor portions including a changing mechanism for changing an axial position of the one rotor portion relative to an axial position of the other rotor portion in accordance with a direction of torque of the rotor; the one rotor portion being supported from axially opposite sides by a support mechanism.
A rotational electric machine comprising: a stator having windings; and a split rotor rotatably disposed on an inner circumferential side of the stator through an air gap and axially divided into two rotor portions, the rotor portions having different-polarity field magnets disposed alternately in a rotational direction; one of the rotor portions including a changing mechanism for changing a phase of synthesized magnetic poles of the field magnets relative to that of magnetic poles of the other rotor portion in accordance with a direction of torque of the rotor; the one rotor portion is supported from axially opposite sides by a support mechanism.
A rotational electric machine comprising: a stator having windings; and a split rotor rotatably disposed on an inner circumferential side of the stator through an air gap and axially divided into two rotor portions, the rotor portions having different-polarity field magnets disposed alternately in a rotational direction; one of the rotor portions including a changing mechanism for changing an axial position of the one rotor portion relative to that of the other rotor portion while shifting a magnetic pole center of the field magnets disposed in the one rotor portion and another magnetic pole center of the field magnets disposed in the other rotor portion in accordance with a direction of torque of the rotor, the one rotor portion being supported from axially opposite sides by a support mechanism.
A rotational electric machine comprising: a stator having windings; and a split rotor rotatably disposed on an inner circumferential side of the stator through an air gap and axially divided into two rotor portions, the rotor portions having different-polarity field magnets disposed alternately in a rotational direction; one of the rotor portions including a changing mechanism for changing a phase of synthesized magnetic poles of the field magnets relative to that of magnetic poles of the field magnets of the other rotor portion while shifting a magnetic pole center of the field magnets disposed in the one rotor portion and another magnetic pole center of the field magnets disposed in the other rotor portion in accordance with a direction of torque of the rotor, the one rotor portion being supported from axially opposite sides by a support mechanism.
A rotational electric machine comprising: a stator having windings; and a split rotor rotatably disposed on an inner circumferential side of the stator through an air gap and axially divided into two rotor portions, the rotor portions having different-polarity field magnets disposed alternately in a rotational direction; one of the rotor portions including a changing mechanism for changing an axial position of the one rotor portion relative to that of the other rotor portion while truing up a magnetic pole center of the field magnets disposed in the one rotor portion and another magnetic pole center of the field magnets disposed in the other rotor portion in accordance with a direction of torque
Joong Kim Houng
Okabe Satoru
Crowell & Moring LLP
Hitachi , Ltd.
Waks Joseph
LandOfFree
Rotational electric machine and a vehicle loaded therewith does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Rotational electric machine and a vehicle loaded therewith, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Rotational electric machine and a vehicle loaded therewith will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3278058