Electric Motor

Abstract

This electric motor is provided with: an inner periphery side rotor provided with inner peripheral permanent magnets with unlike poles, which are disposed alternately along a circumferential direction; an outer periphery side rotor provided with outer peripheral permanent magnets with unlike poles, which are disposed alternately along a circumferential direction, the outer periphery side rotor being arranged such that a rotational axis thereof is coaxial with a rotational axis of the inner periphery side rotor; and a rotating device that varies a relative phase between the inner periphery side rotor and the outer periphery side rotor by rotating at least the inner periphery side rotor or the outer periphery side rotor around the rotational axis, and sets a variable width of the relative phase between the inner periphery side rotor and the outer periphery side rotor within a range of an electrical angle of below 180°.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of an essential portion of an electric motor according to a first embodiment of the present invention.

FIG. 2 is an elevation view showing an inner periphery side rotor and an outer periphery side rotor, without a drive plate in front, and showing a weak magnetic field state of a rotating mechanism of the electric motor.

FIG. 3 is an exploded perspective view showing the inner periphery side rotor, the outer periphery side rotor, and the rotating mechanism of the electric motor.

FIG. 4 is an elevation view showing an inner periphery side rotor and an outer periphery side rotor, without a drive plate in front, and showing a strong magnetic field state of a rotating mechanism of the electric motor.

FIG. 5 is a graph showing the relationship between the electrical angle and the relative torque of the inner periphery side rotor and the outer periphery side rotor of the electric motor.

FIG. 6A schematically shows the strong magnetic field state of permanent magnets of the inner periphery side rotor and permanent magnets of the outer periphery side rotor disposed in an unlike-pole facing arrangement. FIG. 6B schematically shows the weak magnetic field state of the poles of the permanent magnets of the inner periphery side rotor and the permanent magnets of the outer periphery side rotor disposed in a like-pole facing arrangement.

FIG. 7 is a graph showing the induced voltage in the strong magnetic field state and the weak magnetic field state shown in FIGS. 6A and 6B.

FIG. 8A is a graph showing the relationship between the electric current and the torque of the electric motor that vary in response to the induced voltage constant Ke. FIG. 8B is a graph showing the relationship between the rotational speed and the field weakening loss of the electric motor that vary in response to the induced voltage constant Ke.

FIG. 9 shows the operable region for the rotational speed and the torque of the electric motor that varies in response to the induced voltage constant.

FIG. 10A is a graph showing the relationship between the electric current and the rotational speed of the electric motor that vary in response to the induced voltage constant Ke. FIG. 10B is a graph showing the relationship between the rotational speed and the output of the electric motor that vary in response to the induced voltage constant Ke.

FIG. 11A shows the distribution of operable regions and efficiency for the rotational speed and the torque of the electric motor that vary in response to the induced voltage constant Ke in an example. FIG. 11B shows the distribution of operable regions and the efficiency for the rotational speed and the torque of the electric motor that vary in response to the induced voltage constant Ke in a second comparative example.

FIG. 12 is a cross-sectional view showing an inner periphery side rotor, an outer periphery side rotor, and a rotating mechanism of an electric motor in a weak magnetic field state, according to a second embodiment of the present invention.

FIG. 13 is an elevation view showing the inner periphery side rotor, the outer periphery side rotor, and the rotating mechanism of the electric motor in the weak magnetic field state, wherein one part thereof is shown in a cross-section and a drive plate in front is removed.

FIG. 14 is a hydraulic circuit diagram with the focus on a hydraulic control device of a fourth embodiment of the present invention.

FIG. 15 is a schematic cross-sectional view of a flow passage switching valve of the fourth embodiment.

FIG. 16 is a schematic cross-sectional view of a pressure regulating valve of the fourth embodiment.

FIG. 17 is a schematic cross-sectional view of the flow passage switching valve of the fourth embodiment.

FIG. 18 is a schematic cross-sectional view of the regulating valve of the fourth embodiment.

FIGS. 19A to 19C show the fourth embodiment. Operations of devices which linearly increases the rotary reaction force are sequentially shown in the schematic cross-sectional views of FIG. 19A, FIG. 19B and FIG. 19C.

FIG. 20 is a characteristics diagram showing the state of change in the rotary reaction force in response to increasing relative rotational angle of the inner periphery side rotor.

FIG. 21 is a hydraulic circuit diagram with the focus on a hydraulic control device in an electric motor of a fifth embodiment of the present invention.

Claims

1. An electric motor comprising: an inner periphery side rotor provided with inner peripheral permanent magnets with unlike poles, which are disposed alternately along a circumferential direction;an outer periphery side rotor provided with outer peripheral permanent magnets with unlike poles, which are disposed alternately along a circumferential direction, the outer periphery side rotor being arranged such that a rotational axis thereof is coaxial with a rotational axis of the inner periphery side rotor; anda rotating device that varies a relative phase between the inner periphery side rotor and the outer periphery side rotor by rotating at least the inner periphery side rotor or the outer periphery side rotor around the rotational axis, and sets a variable width of the relative phase between the inner periphery side rotor and the outer periphery side rotor within a range of an electrical angle of below 180°.

2. The electric motor according to claim 1, wherein the rotating device:comprises a first member integrally and rotatably provided to the outer periphery side rotor, and a second member integrally and rotatably provided to the inner periphery side rotor which together with the first member defines a pressure chamber on the inside of the inner periphery side rotor; andvaries the relative phase between the inner periphery side rotor and the outer periphery side rotor by supplying a hydraulic fluid to the pressure chamber.

3. The electric motor according to claim 2, wherein the variable width of the relative phase between the inner periphery side rotor and the outer periphery side rotor is set within a range of an electrical angle of below 180° by mechanically restricting the variable width of the relative phase of the second member in relation to the first member.

4. The electric motor according to claim 2, wherein the variable width of the relative phase between the inner periphery side rotor and the outer periphery side rotor is set within a range of an electrical angle of below 180° by restricting the variable width of the relative phase of the second member in relation to the first member with a hydraulic fluid supplied to the pressure chamber.

5. The electric motor according to claim 2, wherein: the first member is a vane rotor disposed on the inside of the inner periphery side rotor, and is integrally provided to the outer periphery side rotor; andthe second member is a housing with a groove which together with the vane rotor, defines the pressure chamber and is integrally installed on the inside of the inner periphery side rotor while rotatably housing blades of the vane rotor.

6. The electric motor according to claim 2, wherein: the first member is a drive plate integrally provided to a rotating shaft and the outer periphery side rotor so as to cover two end faces of the inner periphery side rotor and the outer periphery side rotor, which transmits a rotating force to the rotating shaft; andthe second member is a ring gear disposed between the inner periphery side rotor and the rotating shaft, and is connected to the inner periphery side rotor and the rotating shaft by helical splines, which together with the drive plate, defines the pressure chamber, and which moves in the axial direction to supply a hydraulic oil to the pressure chamber.

7. The electric motor according to claim 2, wherein: the first member is a housing integrally provided to the outer periphery side rotor and a rotating shaft that transmits the drive force of the outer periphery side rotor; andthe second member is a piston inserted in a hole formed in the housing, which together with the hole, defines the pressure chamber, and is in contact with a wall face of the inner periphery side rotor.

8. The electric motor according to claim 1, wherein the rotating device sets the positions at which the unlike poles of the outer peripheral permanent magnet and the inner peripheral permanent magnet facing each other at the home positions of the outer periphery side rotor and the inner periphery side rotor, and varies the relative phase between the inner periphery side rotor and the outer periphery side rotor from the home positions in the range of electrical angles of below 180°.

9. The electric motor according to claim 8, wherein the position at which the fluid pressure is initially supplied to the pressure chamber is taken as a start position for phase change from the home position.