Rotary motor

Abstract

This invention provides a rotary motor. The rotary motor includes a rotor shaft, a first rotor integrally rotated with the rotor shaft, a second rotor rotatably supported by the rotor shaft relative to the first rotor, and a stator that generates a magnetic field around the first and second rotors. By adjusting the relative rotational position of the second rotor relative to the first rotor, the magnetic flux can be changed. Furthermore, the rotary motor includes a stop block integrally rotated with the rotor shaft and one of the second and second rotors, and a pin integrally rotated with the other and in contact with the surface of the stop block. When the second rotor rotates relative to the first rotor, the stop block and the pin move relative to each other, and simultaneously the surface of the stop block slides into contact with the pin. Based on the above structure of this invention, a rotary motor with a variable magnetomotive force mechanism that can control the contact friction force between the rotors can be realized.

Description

Technical Field

[0001] This utility model relates to rotary motors, and in particular to improvements of rotary motors with a variable magnetomotive force mechanism. Background Technology

[0002] As a rotary motor that can be installed in hybrid or electric vehicles, there is, for example, a rotary motor with a variable magnetomotive force mechanism. This rotary motor includes a rotor shaft, a first rotor (also called a fixed rotor) that rotates integrally with the rotor shaft, a second rotor (also called a rotating rotor) that is rotatably supported by the rotor shaft relative to the first rotor, and a stator that generates a magnetic field (rotating magnetic field) around the first and second rotors. The first and second rotors are respectively configured such that permanent magnets with S poles on their outer periphery and permanent magnets with N poles on their outer periphery are alternately arranged in the circumferential direction. Furthermore, by adjusting the rotational position of the second rotor relative to the first rotor (hereinafter also referred to as the relative rotational position between rotors), the magnetic flux (magnetic field flux) of the rotor can be changed.

[0003] In a variable magnetomotive force mechanism, the magnetic flux of the rotor is maximized when the N and S poles of the permanent magnets of the first and second rotors are in phase circumferentially (i.e., like poles facing each other). Conversely, the magnetic flux of the rotor is minimized when the N pole of the permanent magnet of the first rotor and the S pole of the permanent magnet of the second rotor are in phase circumferentially, and the S pole of the permanent magnet of the first rotor and the N pole of the permanent magnet of the second rotor are in phase circumferentially (i.e., opposite poles facing each other).

[0004] A rotary electric motor with a variable magnetomotive force mechanism can, for example, be used as the first electric generator in a hybrid vehicle equipped with a first electric generator (primarily used for power generation and engine starting) and a second electric generator (primarily used for driving in electric mode). In this case, when driving in electric mode driven by the second electric generator, by making the first electric generator in a reverse polarity state, the losses caused by the rotational resistance of the first electric generator (i.e., so-called drag losses) can be reduced.

[0005] However, in such a rotating electric motor with a variable magnetomotive force mechanism, the second rotor will rotate relative to the first rotor, depending on the relationship (magnitude) between the contact friction force between the rotors and the torque generated by each rotor. That is, when the difference in torque between the rotors in the direction of rotation is greater than the contact friction force between the rotors, the second rotor will rotate relative to the first rotor. Furthermore, the contact friction force between the rotors depends on the electromagnetic force between them (i.e., the magnetic force that varies depending on the degree of overlap between the N pole of the permanent magnet of the first rotor and the S pole of the permanent magnet of the second rotor, i.e., attraction). Therefore, the magnitude of this contact friction force varies according to the relative rotational position of the rotors.

[0006] In the aforementioned prior art, since the contact friction between the rotors depends on the electromagnetic force between them, the change in contact friction is unstable when the relative rotation of the rotors changes. This makes it difficult to control the current value (stator coil current value) based on the contact friction to adjust the relative rotation speed of the rotors. Therefore, for example, it is impossible to implement high-precision adjustment such as reducing the relative rotation speed before the pin used to stop the relative rotation of the rotors hits the stop block. This results in the pin hitting the stop block at a high speed, generating significant noise and vibration. Such noise and vibration transmitted into the passenger compartment can cause discomfort to passengers. Utility Model Content

[0007] In view of the above situation, the purpose of this utility model is to provide a rotary motor with a variable magnetomotive force mechanism that can control the contact friction force between rotors.

[0008] As a technical solution to the above-mentioned technical problems, this utility model provides a rotary motor, which includes a rotor shaft, a first rotor that rotates integrally with the rotor shaft, a second rotor that is rotatably supported by the rotor shaft relative to the first rotor, and a stator that generates a magnetic field around the first rotor and the second rotor. By adjusting the relative rotational position of the second rotor relative to the first rotor, the magnetic flux can be changed. The motor is characterized by having a stop block that rotates integrally with one of the rotor shaft and the second rotor, and a pin that rotates integrally with the other and contacts the surface of the stop block. When the second rotor rotates relative to the first rotor, the stop block and the pin move relative to each other while the surface of the stop block slides in contact with the pin.

[0009] The advantage of the rotary motor of this invention, possessing the above-described structure, lies in its ability to control the contact friction force between the rotors. Specifically, when the second rotor rotates relative to the first rotor, the surface of the stop block slides into contact with the pin, thereby generating sliding resistance against the relative rotation between the first and second rotors. By designing the shape of the stop block surface or the pin, the contact friction force generated when the stop block surface slides into contact with the pin can be controlled in advance. Therefore, based on the relative rotational position of the rotors, the contact friction force can be controlled, so that when the rotational amount of the rotors changes, the contact friction force can change stably according to the pre-design. Thus, based on the above structure, by employing a physical contact friction force generating mechanism (the structure of the stop block surface sliding into contact with the pin) that can obtain a pre-designed stable contact friction force, compared to the prior art where a stable contact friction force cannot be obtained and can only be generated by the electromagnetic force between the rotors, the contact friction force corresponding to the relative rotational position of the rotors can be controlled. Therefore, the current value can be controlled according to this contact friction force, thereby adjusting the relative rotational speed of the rotors. Therefore, by controlling the current value to reduce the relative rotational speed just before the pin hits the stop, for example, the noise and vibration caused by the collision can be reduced.

[0010] In addition, in the above-mentioned rotary motor of the present invention, it is preferred that the stop block rotates integrally with the rotor shaft, and the pin rotates integrally with the second rotor; a stop block surface is formed on the stop block to limit the relative rotational position of the second rotor relative to the first rotor; the pin is arranged at a position that can contact the outer peripheral surface of the stop block, and the outer diameter of the stop block is set to gradually increase as it gets closer to the stop block surface.

[0011] Based on this structure, as the distance between the pin and the stop surface of the stop decreases, the contact force between the pin and the stop gradually increases. Therefore, the relative velocity when the pin and the stop surface abut against each other gradually decreases as the contact force increases. This reduces the noise and vibration generated when the pin collides with the stop. Attached Figure Description

[0012] Figure 1 is a cross-sectional view showing a portion of the basic structure of the rotary electric motor according to an embodiment of the present invention.

[0013] Figure 2A is a diagram showing the state where the first rotor and the second rotor are facing opposite poles.

[0014] Figure 2B is a diagram showing the state where the first rotor and the second rotor are facing each other with the same pole.

[0015] Figure 3 is a three-dimensional view showing the block, pin, and surrounding structure enlarged.

[0016] Figure 4 is a cross-sectional view of the pin and its surrounding structure in the modified example. Detailed Implementation

[0017] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In this embodiment, the present invention will be described in the case of applying the present invention to an electric generator mounted on a hybrid electric vehicle.

[0018] <Basic Structure of Rotary Electrical Machines>

[0019] First, the basic structure of the rotary electric motor of this embodiment will be described. FIG1 is a cross-sectional view showing a portion of the basic structure of the rotary electric motor 1 of this embodiment. As shown in FIG1, the rotary electric motor 1 includes a stator 2 located on the outer periphery and a rotor 3 located on the inner periphery.

[0020] The stator 2 has a stator core 21 and three-phase stator coils 22u, 22v, and 22w arranged circumferentially along the stator core 21. When the three-phase alternating current passes through the stator coils 22u, 22v, and 22w, a rotating magnetic field is generated.

[0021] The rotor 3 includes a first rotor 4 and a second rotor 5 arranged adjacent to each other in the axial direction (direction of rotation). The first rotor 4 and the second rotor 5 are arranged facing each other with a small gap in the axial direction and can rotate relative to each other. More precisely, the rotor 3 of the rotary electric motor 1 includes a first rotor (fixed rotor) 4 and two second rotors (rotating rotors) arranged on both sides of the first rotor 4 along the axial direction of the first rotor 4. Figure 1 only shows the structural relationship between the first rotor 4 and one of the second rotors 5, but the structural relationship between the first rotor 4 and the other second rotor 5 is the same (specifically, it is a structure that is symmetrical to the left and right of Figure 1).

[0022] As shown in Figure 1, the first rotor 4 includes a first rotor core 41 formed by stacking multiple electromagnetic steel plates axially, and a plurality of first permanent magnets (42n, 42s) arranged circumferentially at equal intervals within the first rotor core 41. As shown in Figure 2 (Figures 2A and 2B) described later, the first permanent magnet 42n is configured with its N pole near the outer periphery, and the first permanent magnet 42s is configured with its S pole near the outer periphery. By alternating the circumferential arrangement of the first permanent magnets 42n and 42s, the polarities of the first permanent magnets 42n and 42s alternate in the circumferential direction.

[0023] As shown in Figure 1, the second rotor 5 includes a second rotor core 51 formed by stacking multiple electromagnetic steel plates axially, and a plurality of second permanent magnets (52n, 52s) arranged circumferentially at equal intervals within the second rotor core 51. As shown in Figure 2 (described later), the second permanent magnet 52n is configured with its N pole near the outer periphery, and the second permanent magnet 52s is configured with its S pole near the outer periphery. By alternating the circumferential arrangement of the second permanent magnets 52n and 52s, the polarities of the second permanent magnets 52n and 52s alternate in the circumferential direction. Here, the circumferential spacing of the second permanent magnets 52n and 52s is equal to the circumferential spacing of the first permanent magnets 42n and 42s.

[0024] As shown in Figure 1, the rotor shaft supporting the first rotor 4 and the second rotor 5 includes a first rotor shaft 6 and a second rotor shaft 7.

[0025] Binding plates 61 and 62 are fixedly joined to the first rotor shaft 6 by welding or the like. Binding plates 61 and 62 are arranged axially at a predetermined interval, with binding plate 61 positioned axially on one side of binding plate 62 (hereinafter, the left side in Figure 1 is referred to as one side, and the right side in Figure 1 is referred to as the other side). The first rotor 4 is sandwiched between binding plates 61 and 62. The first rotor 4 is connected to the first rotor shaft 6 via a keyway or spline, and rotates integrally with the first rotor shaft 6, binding plates 61 and 62.

[0026] Binding plates 71 and 72 are fixedly joined to the second rotor shaft 7 by welding or other means. Binding plates 71 and 72 are arranged axially at a predetermined interval, with binding plate 71 positioned axially on the other side of binding plate 72. The second rotor 5 is sandwiched between binding plates 71 and 72. The second rotor 5 is connected to the second rotor shaft 7 via a keyway or spline, and rotates integrally with the second rotor shaft 7, binding plates 71 and 72. The second rotor shaft 7 is rotatably supported relative to the first rotor shaft 6 by bearings 73, thereby allowing the second rotor 5 to rotate relative to the first rotor 4.

[0027] Furthermore, the range of variation of the inter-rotor phase angle γ (phase difference) between the second rotor 5 and the first rotor 4 is limited. The structure for limiting this range will be described later. Specifically, the range of variation of the inter-rotor phase angle γ between the first rotor 4 and the second rotor 5 can be limited to, for example, an electrical angle range of 0° to 180° or a range of -180° to 0°.

[0028] By adjusting the relative rotational position of the second rotor 5 relative to the first rotor 4, the magnetic flux (magnetic field flux) of rotor 3 can be changed. Figure 2A shows the state where the first rotor 4 and the second rotor 5 face each other with opposite poles. Figure 2B shows the state where the first rotor 4 and the second rotor 5 face each other with the same poles.

[0029] In the same-pole-facing state shown in Figure 2B, that is, when the first permanent magnet 42n of the first rotor 4 and the second permanent magnet 52n of the second rotor 5 are arranged in the same phase in the circumferential direction, and the first permanent magnet 42s of the first rotor 4 and the second permanent magnet 52s of the second rotor 5 are arranged in the same phase in the circumferential direction, the magnetic flux of rotor 3 is at its maximum.

[0030] Conversely, when the second rotor 5 rotates from the state shown in Figure 2B to the state of opposite poles relative to the first rotor 4 as shown in Figure 2A, that is, when the first permanent magnet 42n of the first rotor 4 and the second permanent magnet 52s of the second rotor 5 are arranged in phase in the circumferential direction, and the first permanent magnet 42s of the first rotor 4 and the second permanent magnet 52n of the second rotor 5 are arranged in phase in the circumferential direction, the magnetic flux of the rotor 3 is at its minimum.

[0031] In this way, the phase relationship between the first rotor 4 and the second rotor 5 of the rotary electric machine 1 in this embodiment can be changed. That is, the rotary electric machine 1 can function as a variable magnetic field type rotary electric machine that changes the phase angle γ between the rotors by rotating the first rotor 4 and the second rotor 5 relative to each other, thereby changing the magnetic flux of the rotor 3 (the excitation magnetic flux of the rotor 3 acting on the stator 2).

[0032] The rotary motor 1 of this embodiment can be used, for example, as an electric generator (MG) in a hybrid electric vehicle. When the rotary motor 1 is operated by the on-board electronic control unit (ECU) 100, the rotor phase angle γ between the first rotor 4 and the second rotor 5 is controlled to 0° to maximize the linkage flux of the stator 2; when the rotary motor 1 is stopped, the rotor phase angle γ between the first rotor 4 and the second rotor 5 is controlled to 180° to minimize the linkage flux of the stator 2.

[0033] In addition to the control method disclosed in Japanese Patent Application Publication No. 2017-225231, the following method can also be used to control the phase angle between rotors in the ECU100, without directly detecting the relative rotational position of the second rotor 5 relative to the first rotor 4.

[0034] That is, when transitioning from a state of same-pole facing to a state of opposite-pole facing, or from a state of opposite-pole facing to a state of same-pole facing, in order to obtain the target relative rotational speed in each phase (the relative rotational position of the second rotor 5 relative to the first rotor 4), the current rotational position of the second rotor 5 relative to the first rotor 4 is first estimated. Then, based on the estimated relative rotational position, the stator current value is calculated from the current total contact friction force, and the rotating motor 1 is driven by supplying this stator current to the stator coils (22u, 22v, 22w). Furthermore, the total contact friction force is the sum of the electromagnetic force between the rotors (4, 5) and the friction force generated by the sliding contact between the stop 8 and the pin 9 (described later). The electromagnetic force between the rotors (4, 5) depends on the magnetic force (attraction) that varies depending on the degree of overlap between the N pole of the permanent magnet of the first rotor 4 and the S pole of the permanent magnet of the second rotor 5. The friction force generated by the sliding contact between the stop 8 and the pin 9 will be described later. In addition, the current estimation of the relative rotational position of the second rotor 5 relative to the first rotor 4 is based on the cumulative value of the total contact friction force corresponding to each of the previously estimated relative rotational positions, the stator current value corresponding to each of the relative rotational positions, and the duration of the current flowing through that stator current value.

[0035] <Mechanism for generating contact friction>

[0036] The contact friction generating mechanism, a feature of this embodiment, will now be described. This contact friction generating mechanism generates a physical contact friction force that resists a predetermined resistance to the rotation of the second rotor 5 relative to the first rotor 4. This contact friction generating mechanism is disposed on both sides of the axial direction. The following description will take a contact friction generating mechanism disposed on one side of the axial direction as an example.

[0037] As shown in Figures 1 and 2, a disc-shaped stop 8 that rotates integrally with the first rotor shaft 6 is mounted on the first rotor shaft 6. Specifically, the stop 8 is mounted on the first rotor shaft 6 at a position outer of the second rotor 5. More specifically, with a portion of the fastening member 81 fitted into the central opening 82 of the stop 8, the stop 8 can be rotatably mounted on the first rotor shaft 6 integrally with the first rotor shaft 6 by fastening the fastening member 81 to the outer circumferential surface of the first rotor shaft 6. However, the mounting structure of the stop 8 on the first rotor shaft 6 is not limited to this.

[0038] Figure 3 is a perspective view showing the stop block, pin 9, and their surrounding structure enlarged. In Figure 3, the vertical direction is parallel to the axial direction (rotation center line). As shown in Figures 2 and 3, the stop block 8 has a small diameter portion 83 with a smaller outer diameter and a large diameter portion 84 with a larger outer diameter than the small diameter portion 83. As shown in Figure 2, the small diameter portion 83 and the large diameter portion 84 are provided in two locations on each side of the stop block 8, and are arranged alternately. In addition, the angle range occupied by the small diameter portion 83 and the large diameter portion 84 is set to 90°. However, this angle range is not limited to this value. In addition, as shown in Figure 3, a stop surface 85 is formed at the junction of the small diameter portion 83 and the large diameter portion 84. This stop surface 85 is configured as a flat surface that extends radially perpendicular to the circumference of the stop block 8.

[0039] The small-diameter portion 83 of the stop block 8 is configured such that its outer diameter varies circumferentially. Specifically, the outer diameter of the small-diameter portion 83 is set to gradually increase toward the stop block surface 85 (the closer to the stop block surface 85, the larger it is). That is, in Figure 3, the outer diameter R2 (the outer diameter of the region close to the stop block surface 85) is greater than the outer diameter R1 (the outer diameter of the region far from the stop block surface 85).

[0040] Additionally, a protruding pin 9 is provided on one side of the restraint plate 72, which rotates integrally with the second rotor 5 (the side facing away from the first rotor 4). As shown in FIG3, the pin 9 has a cylindrical first cylindrical portion 91 protruding from the outer peripheral surface (upper surface in FIG3) of the restraint plate 72, a frustum-shaped abutment portion 92 connected to the outer side of the first cylindrical portion 91, and a cylindrical second cylindrical portion 93 connected to the outer side of the abutment portion 92.

[0041] Furthermore, the pin 9 on the outer peripheral surface of the restraint plate 72 is positioned such that the abutment portion 92 can contact the outer peripheral surface 83a of the small diameter portion 83 of the stop block 8.

[0042] Based on this structure, when switching from the reverse polarity facing state shown in FIG2A to the same polarity facing state shown in FIG2B, the abutting portion 92 of pin 9 moves from the region with a small outer diameter of the small diameter portion 83 of stop 8 to the region with a large outer diameter. Therefore, the contact force between the abutting portion 92 of pin 9 and the outer peripheral surface 83a of the small diameter portion 83 of stop 8 increases with relative rotation, that is, the contact friction between stop 8 and pin 9 gradually increases.

[0043] Using the aforementioned contact friction generating mechanism, the contact friction force generated by the sliding contact between the abutment portion 92 of the pin 9 and the outer peripheral surface 83a of the small diameter portion 83 of the stop 8 can be pre-controlled according to the design shape of the abutment portion 92 of the pin 9 and the design shape of the small diameter portion 83 of the stop 8. That is, the contact friction force can be controlled according to the relative rotational position of the rotors (4, 5), so that when the relative rotational amount of the rotors (4, 5) changes, the contact friction force can change stably according to the design.

[0044] <Effects of the Implementation Method>

[0045] As described above, in this embodiment, the rotary motor 1 equipped with a variable magnetomotive force mechanism has a stop 8 that rotates integrally with the first rotor shaft 6, and a pin 9 disposed on a restraint plate 72 that rotates integrally with the second rotor 5 and can contact the outer peripheral surface 83a of the stop 8. When the second rotor 5 rotates relative to the first rotor 4, the stop 8 and the pin 9 move relative to each other, and the outer peripheral surface 83a of the stop 8 slides into contact with the pin 9. Thus, by employing a physical contact friction generating mechanism (the structure in which the outer peripheral surface 83a of the stop 8 slides into contact with the pin 9) that can obtain a pre-designed stable contact friction force, compared with the case in the prior art where a stable contact friction force cannot be obtained and the contact friction force can only be obtained by relying on the electromagnetic force between the rotors (4, 5), the contact friction force corresponding to the relative rotational position between the rotors (4, 5) can be grasped, thereby enabling the current value to be controlled according to the contact friction force to adjust the relative rotational speed of the rotors (4, 5). Therefore, by controlling the current value to reduce the relative rotational speed when the pin 9 is about to hit the stop surface 85 of the stop block 8, it is possible to reduce noise and vibration caused by the collision.

[0046] <Variation Example>

[0047] Next, a modified example will be described. This modified example differs from the above embodiment only in the structure of the stop block 8. All other structures and principles are the same as the above embodiment; therefore, only the structure of the stop block 8 will be described here.

[0048] Figure 4 is a cross-sectional view of the pin 9 and its surrounding structure in this modified example. The stop block 8 in this modified example shown in Figure 4 is configured such that a portion of its lower part is cut off to form a recess 86, in which the movable member 88 and the coil spring 87 are accommodated. The lower surface 88a of the movable member 88 is configured as an inclined surface that substantially coincides with the inclined surface of the abutment portion 92 of the pin 9, and this lower surface 88a slides in contact with the inclined surface of the abutment portion 92 of the pin 9.

[0049] In this modified example, the movable member 88 is pressed against the abutment portion 92 of the pin 9 by the elastic force of the coil spring 87. As a result, the contact friction between the movable member 88 and the pin 9 can be maintained at approximately a certain value regardless of the relative rotational position of the rotors (4, 5).

[0050] In the above embodiments, the contact friction force between the stop 8 and the pin 9 varies according to the relative rotational position of the rotors (4, 5). In this modified example, the contact friction force is maintained at approximately a certain value, thus making it easier to control the contact friction force between the rotors (4, 5). As a result, the relative rotational speed between the rotors (4, 5) can be easily adjusted by controlling the current value.

[0051] <Other Implementation Methods>

[0052] This utility model is not limited to the above-described embodiments, and various modifications and applications can be implemented within the scope of the claims and their equivalents.

[0053] For example, in the above embodiments and modifications, the application of the rotary motor 1 of this invention to an electric generator mounted on a hybrid electric vehicle has been described. However, this invention is not limited thereto, and is also applicable to electric generators mounted on plug-in hybrid electric vehicles or electric vehicles.

[0054] Furthermore, in the above embodiments and modifications, contact friction is generated by abutting the outer peripheral surface 83 of the stop block 8 against the pin 9. However, the present invention is not limited to this; contact friction can also be generated by abutting the inner peripheral surface of the stop block 8 against the pin 9.

[0055] Furthermore, in the above embodiment, the contact friction force between the stop block 8 and the pin 9 varies according to the relative rotational position of the rotors (4, 5), causing the outer diameter of the small-diameter portion 83 of the stop block 8 to vary circumferentially. However, this invention is not limited to this, and other structures can be used to make the contact friction force between the stop block 8 and the pin 9 vary according to the relative rotational position of the rotors (4, 5). For example, the thickness of the stop block 8 can be varied circumferentially.

[0056] Furthermore, in the above embodiments and modifications, a stop 8 is installed on the first rotor shaft 6, and a protruding pin 9 is provided on the restraint plate 72 that rotates integrally with the second rotor 5. However, the present invention is not limited to this, and a stop 8 may also be installed on a component that rotates integrally with the second rotor 5, and a protruding pin may be provided on the first rotor shaft 6.

Claims

1. A rotary electric motor, comprising a rotor shaft, a first rotor integrally rotatable with the rotor shaft, a second rotor rotatably supported by the rotor shaft relative to the first rotor, and a stator generating a magnetic field around the first rotor and the second rotor, wherein the magnetic flux can be changed by adjusting the relative rotational position of the second rotor relative to the first rotor, characterized in that: It includes a stop that rotates integrally with one of the rotor shaft and the second rotor, and a pin that rotates integrally with the other rotor and contacts the surface of the stop. When the second rotor rotates relative to the first rotor, the stop block and the pin move relative to each other, and the surface of the stop block slides into contact with the pin.

2. The rotary motor as described in claim 1, characterized in that: The stop block rotates integrally with the rotor shaft, and the pin rotates integrally with the second rotor; A stop surface is formed on the stop block to limit the relative rotational position of the second rotor relative to the first rotor; The pin is positioned to contact the outer peripheral surface of the stop block, and the outer diameter of the stop block is set to gradually increase as it gets closer to the stop block surface.

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