1. Field of the Invention
The present invention relates to a coupling plate for rotating electric machine and particularly to a coupling plate used in an engine-driven generator for connecting the engine to the generator.
2. Related Art
The engine-driven generator is to drive a generator by obtaining a driving force from an engine. However, since an engine generates axial vibration which is harmful for driving together with a torque required for driving of the generator, a coupling plate is interposed between the engine and the generator to transmit only the torque (a plate between a cooling fan 8 and a disk 9 in the Patent Document 2, FIG. 3).
Also, a rotating electric machine generates vibration if a rotor is not balanced, which causes a problem of damage on a bearing, generation of a noise, reduction of machine life and so on. Then, in order to achieve a balance, a balance weight is attached on a rotor after assembling of the rotor.
And in order to achieve a rotating balance of rotating electric machine, a disk for mounting the balance weight at a rotating shaft is provided and the balance is fixed by selecting an appropriate position on this disk (See the Patent Documents 1 and 2).
[Patent Document 1] Japanese Utility Model Laid-Open No. S61-74271
[Patent Document 2] Japanese Patent Laid-Open No. H9-298863
Here, the rotating electrical machine is now required to reduce its size and weight and to simplify the structure as a general request for electrical machine, and particularly reduction in the number of parts and the length in the axial direction is in demand. Therefore, there is a demand to reduce the number of members to be mounted on a shaft of rotating electrical machine as much as possible.
Therefore, the above incorporation of a disk only to mount a balance weight onto a shaft of rotating electrical machine is a problem to be improved in machine design.
The present invention was made in view of the above and its object is to provide a coupling plate on which a balance weight can be mounted and which can maintain a function to absorb natural axial vibration with a simple structure.