Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2000-11-17
2003-07-08
Ramirez, Nestor (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S114000, C310S156010, C310S156530, C310S156570, C310S156490, C310S156120, C310S156370
Reexamination Certificate
active
06590312
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a vehicle rotary electric machine for an electric vehicle, and, more particularly, a rotary electric machine that starts an engine, assists the engine to drive wheels and regenerates electric power from running energy of a vehicle.
2. Description of the Related Art
JP-A-11-78558 proposes a vehicle rotary electric machine (hereinafter referred to as the vehicle-rear rotary electric machine) including a rotor connected between an engine and a gear transmission to be driven by a crank shaft.
The conventional vehicle-rear rotary electric machine makes it possible to mount various belt-driven accessories in front of the engine along a belt, which prevents a pulley of a small diameter from slipping thereon.
However, such a vehicle-rear rotary electric machine has a long power train between a crankshaft and a torque transmission mechanism. The power train includes a clutch disposed at the back of the crankshaft and a torque converter. Therefore, the power train with its housing needs a large mounting space, which may increase a body vibration.
SUMMARY OF THE INVENTION
Therefore, it is an object of the present invention to solve the above-described problems and to provide a compact, light-weight, and high power vehicle-rear-type rotary electric machine.
Such a vehicle-rear-type rotary electric machine (hereinafter referred to as the rear-type machine or the machine) is connected coaxially with a crankshaft. The rear-type machine has a cylindrical stator, a rotor having, an inner rotor portion and an outer rotor portion respectively disposed at opposite peripheral sides of the stator, and a stator winding having a set of multi-phase windings for electro-magnetically connecting with both the rotor portions.
Further, the axial length of the machine can be decreased to about a half thereof. The axial length of the space between the back of the engine and the torque transmission mechanism is reduced to make the power train compact. This naturally restrains vibration of the power train.
If the above inner and outer rotor portions overlap each other in the radial direction, the radial length of the machine increases. However, this increases the flywheel effect of the machine, so that any additional rotary-inertia-member for the flywheel effect can be omitted. In other words, the rotor of the machine according to the invention has a part of or all of the flywheel effect.
The inertia mass of the flywheel is proportional to a square of the mean value of the radius of the flywheel. Therefore, the flywheel effect per weight of the rotor of the machine that has two-radially-combined-rotor-type structure can be drastically improved as compared with the machine that has the single-rotor-type structure.
Moreover, because the opposite peripheral surfaces of a single stator are used for magnetic connection, the core back can be used as a common yoke for the magnetic path of the two rotor portions. This can make the stator more compact and lighter.
Because two rotating magnetic fields generated by the two rotor portions interlink the stator winding, it is possible to shorten the coil ends of the stator winding as compared with a rotary electric machine having respective stators for respective rotor portions.
Moreover, because magnetic fluxes generated by different rotor portions, it is possible to provide a machine that has a combined characteristic of two rotary electric machines.
According to another feature of the invention, the machine further includes a bowl member that connects the torque transmission mechanism and a crank shaft. Therefore, it is not necessary to provide an additional frame for supporting two rotor portions.
According to another feature of the invention, a annular portion supports a larger cylindrical member that supports the outer rotor portion and connects a connecting disk with the transmission mechanism. Therefore, the shape can be simplified, the size and weight can be reduced, and an excellent linkage with the torque transmission mechanism can be provided.
According to another feature of the invention, the stator core has a core back at the radial center thereof. Therefore, the stator core can be made compact and light.
According to a further feature of the invention, each set of the phase windings is wound on one of opposite surfaces of the stator to form a U-shaped cross-section in the circumferential and axial directions. Therefore, the structure and manufacture of the stator can be simplified. In particular, each phase winding is manufactured in the U-shape beforehand so that each can be readily inserted into the inner and outer slot.
According to another feature of the invention, each of the phase windings is wound to form a square cross-section. Therefore, the structure and the manufacture of the stator can be made simple.
Further, each of the phase windings is wound in a toroidal shape (square in cross-section), invalid length per one-turn coil can be made equal to the length a wire passing along opposite ends of the stator core. Therefore, the wire length of the winding can be drastically reduced, the weight of the copper wire can be reduced, and the efficiency thereof can be increased.
According to another feature of the invention, each of the phase windings is wave-wound at approximately the same slot pitches as the magnetic pole pitches so that current flowing at the slot formed at the inner surface and current flowing the slots formed at the outer surface are opposite to each other. Therefore, the stator can be made simple in structure, and the winding can be carried out by a winding machine.
According to another feature of the invention, each of the rotor portions has a rotor-structure having permanent magnets.
According to another feature of the invention, both the rotor portions have a squirrel-cage structure. Therefore, a highly strong and durable rotor can be manufactured at low cost. Moreover, it is possible to control the output voltage from the stator while the engine is operating. Even if the control can not be made, the output voltage does not become too high without providing control means (which needs high voltage insulation).
According to a further feature of the invention, each of the rotor portions has a reluctance-type-rotor-structure. Therefore, the rotor can be manufactured at a low cost.
According to a further feature of the invention, the inner rotor portion has a permanent-magnet-rotor-structure, and the outer rotor portion has a reluctance-type-rotor-structure. Therefore, the output power of the inner rotor portion, which has a small electromagnetic connection area and a small circumferential speed, can be increased, and the drawback of the low-power reluctance rotor can be compensated by a large diameter of the outer rotor.
According to another feature of the invention, the circumferentially central portion of a magnetic salient pole of the reluctance-type-rotor-structure is disposed at a position an electric angle 45°-90° in advance of the circumferentially central portion of a magnetic pole of the permanent-magnet-type-rotor-structure in the rotation direction.
Therefore, the resultant torque and output power can be increased.
According to another feature of the invention, the stator is fixed to the housing by a supporting rod member that is force-fitted to the core back in the axial direction. Therefore, the supporting rod member achieves both to compress the stator core made of laminated iron sheets in the lamination direction and to fix the stator to the housing, without decreasing the area of both surfaces of the electromagnetic connection of the stator core.
According to another feature of the invention, one end of both the rotor portions has a permanent-magnet type-rotor-structure, and the other end of both the rotor portions has a field-coil-type rotor-structure. Therefore, the generation and motor characteristics of the machine can be controlled by the field current control.
According to another feature of the invention, one of the rotor portio
Banzai Keiichiro
Kouda Shinji
Seguchi Masahiro
Yanase Sumio
Yoneda Shigenori
Gonzalez Julio Cesas
Ramirez Nestor
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