In an axial gap rotary electric machine (hereinafter, merely referred to as “rotary electric machine”), a stator and a rotor are disposed with a gap along a rotation axis. Such a configuration has the following advantages. That is, it is possible to increase a magnetic pole surface of a permanent magnet for generating a magnetic field flux, to increase a space factor of a coil with ease, and to increase torque or output in proportion to a size even when slimming down is aimed in a rotation axis direction.
In the rotary electric machine, an attraction force (referred to as “thrust force” herein) acts between the stator and the rotor along a direction parallel to the rotation axis (referred to as “rotation axis direction” herein). This attraction force incurs problems such as an increase in bearing loss and a reduction in bearing life.
In order to prevent a force acting in a thrust axis direction, the following configurations may be employed in the rotary electric machine. For example, two rotors are provided on both sides of one stator along the rotation axis direction. Alternatively, two stators are provided on both sides of one rotor along the rotation axis direction. A pair of thrust forces in directions opposed to each other are generated along the rotation axis direction in any of the above-mentioned two types of configurations, leading to a reduction in thrust force generated in the rotation axis direction as a whole.
Documents related to the present application are as follows.
USPTO Backgrounds
USPTO Backgrounds