Motive power transmission device

Abstract

A motive power transmission device (1) includes an outer magnet shaft (150), a pole piece shaft (160), a selector (170) that selectively stops rotation of one of the outer magnet shaft and the pole piece shaft on the basis of a command, and a magnetic sensor (190) that is disposed in a position affected by a magnetic flux of one or both of a plurality of outer magnetic poles (152A, 152B) and a plurality of magnetic body parts (162) and that detects a magnetic flux density change and the magnitude thereof associated with the rotation of one of the outer magnet shaft and the pole piece shaft.

Description

Power transmission device Cross-reference to related applications

[0001] This application is based on Japanese Patent Application No. 2025-024912 filed on February 19, 2025, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a power transmission device.

[0003] Conventionally, power transmission devices that transmit power generated in a driving-side mechanism unit to a driven-side mechanism unit non-contactingly using magnetic force have been proposed in, for example, Patent Documents 1 and 2.

[0004] The power transmission device includes a non-contact coupling unit that non-contactingly couples a driving-side mechanism unit and a driven-side mechanism unit. The non-contact coupling unit includes a driving-side magnet that constitutes the driving-side mechanism unit, a driven-side magnet that constitutes the driven-side mechanism unit, and a pole piece that modulates magnetic flux between the driving-side magnet and the driven-side magnet. The driving-side magnet is connected to a driving shaft disposed on a rotation axis. The driven-side magnet is connected to a driven shaft disposed on the rotation axis.

[0005] In Patent Document 1, the non-contact coupling unit is disposed on the rotation axes of the driving-side mechanism unit and the driven-side mechanism unit. That is, the driving-side magnet and the driven-side magnet are disposed to face each other on the rotation axis, and the pole piece is fixed between the driving-side magnet and the driven-side magnet. With this configuration, as the driving shaft of the driving-side magnet rotates, the driven shaft of the driven-side magnet rotates.

[0006] In Patent Document 2, the non-contact coupling unit is disposed in the radial direction orthogonal to the rotation axis. That is, the driving-side magnet, the pole piece, and the driven-side magnet are disposed in this order at positions radially away from the rotation axis. The pole piece is connected to a pole piece shaft disposed on the rotation axis. The position of the driven-side magnet is fixed. That is, the driven shaft is not provided. With this configuration, as the driving-side magnet rotates, the pole piece rotates around the rotation axis.

[0007] Japanese Unexamined Patent Application Publication No. 2022-094620, Japanese Unexamined Patent Application Publication No. 2022-094917

[0008] Here, in the configuration described in Patent Document 2, a configuration is conceivable in which rotational power is transmitted to one of the two output shafts by a single drive unit. That is, by connecting a driven magnet to a driven shaft arranged on the rotating shaft, both the pole piece shaft and the driven shaft can be made rotatable. In this configuration, if either the pole piece shaft or the driven shaft is fixed, the other becomes rotatable. Therefore, by switching the shaft that is fixed, rotational power can be transmitted to either the pole piece shaft or the driven shaft by a single drive unit.

[0009] If either the driven shaft or the pole piece shaft is fixed, it is necessary to detect the rotation of both the driven shaft and the pole piece shaft in order to determine whether the other is rotating normally. To detect the rotation of either the driven shaft or the pole piece shaft, one possible approach is to install rotation detection sensors on both the driven shaft and the pole piece shaft, respectively.

[0010] However, since rotation detection is intermittent, occurring with each rotation, it may be difficult to ensure accuracy in rotation detection. Furthermore, since rotation detection sensors will be installed on both the driven shaft and the pole piece shaft, space will be required on the pole piece shaft and driven shaft sides of the power transmission device to accommodate the rotation detection sensors and sensor output mechanisms. This may increase the size of the power transmission device in both the axial and radial directions.

[0011] In view of the above, this disclosure aims to provide a power transmission device that can ensure rotational detection accuracy without increasing the size of the device, in a configuration in which rotational power is transmitted to one of two output shafts by a single drive unit.

[0012] According to a first aspect of this disclosure, the power transmission device includes: an inner magnet shaft having a drive shaft and a plurality of inner magnetic poles provided on the outer circumference of the drive shaft, wherein the plurality of inner magnetic poles rotate integrally with the drive shaft; an outer magnet shaft having a larger number of poles than the plurality of inner magnetic poles of the inner magnet shaft and a plurality of outer magnetic poles arranged on the outer circumference of the plurality of inner magnetic poles, and rotatably supported on the rotation axis of the drive shaft; a pole piece shaft having a plurality of magnetic material parts located between the plurality of inner magnetic poles and the plurality of outer magnetic poles in a radial direction perpendicular to the rotation axis and arranged on the outer circumference of the plurality of inner magnetic poles, rotatably supported on the rotation axis, and rotating by modulating the magnetic flux between the plurality of inner magnetic poles and the plurality of outer magnetic poles; a selector that selectively stops the rotation of either the outer magnet shaft or the pole piece shaft based on a command; and a magnetic sensor positioned in a location affected by the magnetic flux of either or both of the plurality of outer magnetic poles and the plurality of magnetic material parts, and detecting the change in magnetic flux density and its magnitude accompanying the rotation of either the outer magnet shaft or the pole piece shaft.

[0013] According to this method, a magnetic sensor detects the change in magnetic flux density and its magnitude associated with the rotation of the outer magnet shaft or the pole piece shaft. Therefore, it is not necessary to install magnetic sensors and sensor output mechanisms on both the outer magnet shaft and the pole piece shaft. Furthermore, since the magnetic sensor detects the change in magnetic flux density and its magnitude as a continuously changing value, it provides higher rotation detection accuracy than intermittent rotation detection for each rotation. Consequently, rotation detection accuracy can be ensured without increasing the size of the power transmission device.

[0014] According to a second aspect of the present disclosure, the power transmission device includes a drive shaft and a plurality of inner magnetic poles provided on the outer circumference of the drive shaft, an inner magnet shaft having a plurality of inner magnetic poles that rotate integrally with the drive shaft, an outer magnet shaft having a larger number of poles than the plurality of inner magnetic poles of the inner magnet shaft and a plurality of outer magnetic poles arranged on the outer circumference of the plurality of inner magnetic poles, and rotatably supported on the rotation axis of the drive shaft, a pole piece shaft having a plurality of magnetic material parts located between the plurality of inner magnetic poles and the plurality of outer magnetic poles in a radial direction perpendicular to the rotation axis and arranged on the outer circumference of the plurality of inner magnetic poles, rotatably supported on the rotation axis, and rotating by modulating the magnetic flux between the plurality of inner magnetic poles and the plurality of outer magnetic poles, and a selector comprising a selector magnetic material that selectively stops the rotation of either the outer magnet shaft or the pole piece shaft by moving its position relative to the outer magnet shaft and the pole piece shaft based on a command, The system includes a magnetic sensor positioned in a location that is affected by the magnetic flux from the selector's magnetic material, and which detects the magnitude of the magnetic flux density according to the position of the selector relative to the outer magnet axis and the pole piece axis.

[0015] According to this design, the selector position is detected as magnetic flux by a magnetic sensor, eliminating the need to install magnetic sensors and sensor output mechanisms on both the outer magnet shaft and the pole piece shaft. Furthermore, since the magnetic sensor detects magnetic flux corresponding to the selector position, it offers higher rotation detection accuracy than intermittent rotation detection for each rotation. Therefore, rotation detection accuracy can be ensured without increasing the size of the power transmission device.

[0016] The above and other purposes, features and advantages of this disclosure will become clearer from the following detailed description with reference to the attached drawings. In the attached drawings, Figure 1 is a cross-sectional view showing a power transmission device according to the first embodiment, Figure 2 is a cross-sectional view taken along line II-II of Figure 1, Figure 3 is a partial cross-sectional view showing the first selector position of the selector, Figure 4 is a partial cross-sectional view illustrating the rotation of the pole piece shaft, Figure 5 is a partial cross-sectional view showing the second selector position of the selector, Figure 6 is a diagram showing the change in magnetic flux density and its magnitude when the outer magnet shaft rotates, Figure 7 is a partial cross-sectional view illustrating the rotation of the pole piece shaft, and Figure 8 is a diagram showing the magnetic flux density when the pole piece shaft rotates. Figure 9 is a cross-sectional view of a power transmission device according to the second embodiment, Figure 10 is a cross-sectional view of a power transmission device according to the third embodiment, showing the case where the magnetic sensor is arranged on the pole piece circle, Figure 11 is a cross-sectional view of another example of the third embodiment, showing the case where the magnetic sensor is arranged on the outer circle, Figure 12 is a cross-sectional view of another example of the third embodiment, showing the case where the magnetic sensor is arranged on the intermediate circle, and Figure 13 shows the power transmission device according to the fourth embodiment. Figure 14 is a cross-sectional view showing the rotation angle when the outer magnet shaft rotates in the fourth embodiment, Figure 15 is a cross-sectional view showing the rotation angle when the pole piece shaft rotates in the fourth embodiment, Figure 16 is a cross-sectional view showing the case where the first detection unit and the second detection unit are arranged at the first sensor position, and Figure 17 is a diagram showing the first detection signal, the second detection signal, the subtraction result of each detection signal, and the addition result of each detection signal when the pole piece shaft is fixed and the outer magnet shaft rotates at the first sensor position. Figure 18 is a diagram showing the first detection signal, the second detection signal, the subtraction result of each detection signal, and the addition result of each detection signal when the outer magnet shaft is fixed and the pole piece shaft rotates at the first sensor position. Figure 19 is a cross-sectional view showing the case when the first detection unit and the second detection unit are arranged at the second sensor position. Figure 20 is a diagram showing the first detection signal, the second detection signal, the subtraction result of each detection signal, and the addition result of each detection signal when the pole piece shaft is fixed and the outer magnet shaft rotates at the second sensor position. Figure 21 is...Figure 22 shows the first detection signal, the second detection signal, the subtraction result of each detection signal, and the addition result of each detection signal when the outer magnet shaft is fixed and the pole piece shaft rotates at the second sensor position. Figure 23 is a cross-sectional view of Figure 22 along the line XXIII-XXIII. Figure 24 is a cross-sectional view of Figure 24 along the line XXV-XXV. Figure 26 shows the relationship between the axial position of the selector and the magnetic flux density. Figure 27 is a cross-sectional view of Figure 6 along the line XXV. Figure 28 is a diagram illustrating the configuration for acquiring the induced electromotive force of the search coil. Figure 29 is a timing chart showing the current flowing through the coil, the induced electromotive force generated in the search coil, and the displacement of the selector, all acquired by the configuration in Figure 28.

[0017] Several embodiments for carrying out this disclosure are described below with reference to the drawings. In each embodiment, parts corresponding to matters described in a prior embodiment may be denoted by the same reference numerals, and redundant descriptions may be omitted. If only a part of the configuration is described in each embodiment, other parts of the configuration can be applied to other embodiments described in advance. Not only can parts that are explicitly shown to be combinable in each embodiment be combined, but embodiments can also be partially combined even if not explicitly shown, as long as there is no particular impediment to the combination.

[0018] (First Embodiment) The power transmission device according to this embodiment is a valve device that integrates multiple valve devices in a fluid circuit. The power transmission device is configured as an electric multi-way valve that changes the opening degree of a steam pressure regulating valve (EPR) and the opening degree of an expansion valve, respectively, based on the driving force of a single motor. The valve opening degree is, for example, the opening area or the orifice opening degree.

[0019] <Configuration of the power transmission device> As shown in Figure 1, the power transmission device 1 includes a magnetic gear section 10 and a flow path forming section 20 which is connected to the magnetic gear section 10 and operated by the magnetic gear section 10.

[0020] The magnetic gear section 10 generates rotational power and uses that rotational power to operate the flow path forming section 20. The magnetic gear section 10 includes a case 100, a plate member 110, a motor control board 120, a housing 130, an inner magnet shaft 140, an outer magnet shaft 150, a pole piece shaft 160, a selector 170, a holder 180, and a magnetic sensor 190.

[0021] The case 100 houses the plate member 110, the motor control board 120, the inner magnet shaft 140, the outer magnet shaft 150, the pole piece shaft 160, the selector 170, the housing 130, and the holder 180. The case 100 is formed by resin molding of a resin material such as PPS. The case 100 is, for example, a bottomed cylindrical shape. The open end 101 of the case 100 is directed toward the flow path forming section 20. The case 100 is, for example, a hollow rectangular parallelepiped shape.

[0022] The case 100 has a connector section 102 to which wiring such as harnesses are connected. Wiring for the battery that supplies power to the power transmission device 1 and wiring that connects to other electronic devices are connected to the connector section 102. The connector section 102 is provided so as to protrude from the side of the case 100, for example. The connector section 102 may also be provided at the bottom of the case 100.

[0023] The plate member 110 is a metal plate component. The plate member 110 supports the inner magnet shaft 140 and is a reinforcing plate for the bearing of the inner magnet shaft 140. The plate member 110 is a reinforcing plate for suppressing deformation of the motor control board 120.

[0024] The plate member 110 has a plurality of protrusions 111 that protrude from a part of the plate member 110. The plurality of protrusions 111 are inserted into a plurality of through holes 121 provided in the motor control board 120. The plurality of protrusions 111 are also screwed to the bottom 131 of the housing 130. The plurality of protrusions 111 may also be fixed to the bottom 131 of the housing 130 by welding or the like.

[0025] The motor control board 120 is a control device for controlling the rotation of the inner magnet shaft 140, the outer magnet shaft 150, and the pole piece shaft 160. The motor control board 120 has electronic components, such as semiconductor chips (not shown), mounted on it for operating the power transmission device 1. The motor control board 120 is fixed to the plate member 110.

[0026] The motor control board 120 has a plurality of terminals 122 that are electrically connected to external wiring. One end of each terminal 122 is located on the connector portion 102 of the case 100, and the other end is mounted on the motor control board 120. The terminals 122 are insert molded into the case 100. When the motor control board 120 is mounted on the case 100, the terminals 122 are connected to the motor control board 120.

[0027] The motor control board 120 receives control commands from an external electronic device regarding the control of the valve of the flow path forming unit 20, and controls the inner magnet shaft 140 and the selector 170 according to the control commands. For this reason, the motor control board 120 has multiple circuit sections, such as a motor controller, a selector control circuit section, and a determination circuit section. The motor controller is configured, for example, on a semiconductor chip. The selector control circuit section and the determination circuit section are configured, for example, as software or an application within the semiconductor chip.

[0028] The motor controller is electrically connected to the drive motor 141 for rotating the inner magnet shaft 140. The motor controller drives the drive motor 141 using a power conversion circuit that converts DC power supplied from the battery into AC power. The power conversion circuit is composed of, for example, multiple MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors).

[0029] The selector control circuit controls the position of the selector 170 in the axial direction by controlling the supply of current to the coil 171 of the selector 170 according to a control command. Here, the axial direction is the direction along the rotation axis 141B of the drive shaft 141A of the drive motor 141. The selector control circuit outputs control information to the determination circuit unit that allows or prohibits the rotation of the outer magnet shaft 150 and the pole piece shaft 160.

[0030] The determination circuit unit performs an abnormality determination to determine whether the flow path forming unit 20 is operating normally, based on the control information from the selector control circuit unit and the detection signal from the magnetic sensor 190. In other words, the determination circuit unit determines whether the axis rotating based on the control information matches the axis rotating based on the detection signal.

[0031] The determination circuit does not necessarily have to be located on the motor control board 120 (power transmission device 1). For example, an external electronic device may perform abnormality detection of the flow path forming unit 20. In this case, the power transmission device 1 outputs the control information of the selector control circuit and the detection signal of the magnetic sensor 190 to the external electronic device. The external electronic device then determines whether the axis rotating based on the control information matches the axis rotating based on the detection signal. Thus, abnormality detection may be performed inside the power transmission device 1 or by an external device of the power transmission device 1.

[0032] The housing 130 is a bottomed cylindrical metal component. The housing 130 may be a hollow rectangular parallelepiped or a hollow cylinder, similar to the case 100. The housing 130 may be made of a material that is attracted to magnets. The housing 130 houses a portion of the inner magnet shaft 140, the outer magnet shaft 150, the pole piece shaft 160, and the selector 170.

[0033] The housing 130 has a through hole 132 that penetrates the bottom 131 of the closed-bottom cylindrical portion. The drive motor 141 of the inner magnet shaft 140 is located in the through hole 132 of the housing 130. The open end 133 of the housing 130 is fixed to the holder 180.

[0034] The inner magnet shaft 140 is a drive shaft for driving the pole piece shaft 160 and the outer magnet shaft 150. The inner magnet shaft 140 has a drive motor 141 and a plurality of inner magnetic poles 142A, 142B.

[0035] The drive motor 141 is a motor that can be driven by position feedback control. The drive motor 141 in this embodiment is an outer rotor type motor in which the outside of the motor rotates. The drive motor 141 is fixed to the plate member 110.

[0036] The drive motor 141 has a drive shaft 141A, a stator 141C, and a rotor 141D.

[0037] The drive shaft 141A rotates about its rotation axis 141B. The drive shaft 141A is rotatably supported by a bottomed cylindrical first support 141E fixed to the motor control board 120. The stator 141C is fixed to the outer circumferential wall of the first support 141E. As shown in Figure 2, the stator 141C has a stator coil 141F. Three-phase AC power converted by the motor controller is supplied to the stator coil 141F.

[0038] As shown in Figure 1, the rotor 141D includes a second support 141G and a rotor magnet 141H. The second support 141G is a bottomed cylindrical shape, and the drive shaft 141A is fixed to the drive shaft 141A with the drive shaft passing through the bottom of the bottomed cylindrical shape. Therefore, the rotor 141D rotates integrally with the drive shaft 141A.

[0039] The rotor magnet 141H is fixed to the inner circumferential surface of the second support 141G and is positioned opposite the stator 141C. As shown in Figure 2, in this embodiment, the rotor magnet 141H consists of four pairs of magnets in which four north poles and four south poles are alternately arranged in the circumferential direction around the rotation axis 141B.

[0040] The plurality of inner magnetic poles 142A and 142B are provided on the outer periphery of the drive shaft 141A. In the present embodiment, the plurality of inner magnetic poles 142A and 142B are fixed to the outer peripheral surface of the second support 141G of the rotor 141D. As the second support 141G rotates together with the drive shaft 141A, the plurality of inner magnetic poles 142A and 142B rotate integrally with the drive shaft 141A.

[0041] Further, the plurality of inner magnetic poles 142A and 142B are configured as two-pole permanent magnets of an inner N pole 142A and an inner S pole 142B. The plurality of inner magnetic poles 142A and 142B are magnetized along the radial direction orthogonal to the rotation axis 141B. Therefore, the plurality of inner magnetic poles 142A and 142B generate a magnetic field along the radial direction.

[0042] The outer magnet shaft 150 is an output shaft rotatably supported on the rotation axis 14`1B of the drive shaft 141A. The outer magnet shaft 150 has a cylindrical portion 151, a plurality of outer magnetic poles 152A and 152B, an output portion 153, and a friction ring 154.

[0043] The cylindrical portion `151 is a hollow cylindrical component that supports the plurality of outer magnetic poles 152A and 152B. The cylindrical portion 151 is a metal component that rotates about the rotation axis 141B of the drive motor 141. A plurality of outer magnetic poles 152A and 152B are fixed to one end side of the cylindrical portion 151. Thereby, the cylindrical portion 151 constitutes a hollow cylinder together with the plurality of outer magnetic poles 152A and 152B. An output portion 153 is fixed to the other end side of the cylindrical portion 151. Therefore, the cylindrical portion 151 is sandwiched between the output portion 153 and the plurality of outer magnetic poles 152A and `B.

[0044] The plurality of outer magnetic poles 152A and 152B are arranged on the outer periphery of the plurality of inner magnetic poles 142A and 142B. The outer magnetic poles 152A and 152B are an outer N pole 152A and an outer S pole 152B. The plurality of outer N poles 152A and the plurality of outer S poles 152B are magnetized along the radial direction and generate a magnetic field along the radial direction in the same manner as the plurality of inner magnetic poles 142A and 142B.

[0045] The plurality of outer magnetic poles 152A and 152B have more magnetic poles than the plurality of inner magnetic poles 142A and 142B of the inner magnet axis 140. In the present embodiment, the plurality of outer magnetic poles 152A and 152B are provided with 48 poles in the circumferential direction. That is, 24 pairs of outer N poles 152A and outer S poles 152B are provided. The outer N poles 152A and the outer S poles 152B are alternately arranged in the circumferential direction centered on the rotation axis 141B.

[0046] Note that the cylindrical portion 151 and each of the outer magnetic poles 152A and 152B may not be separate bodies and may be integrated. For example, a part of the cylindrical portion 151 configured as a magnetic material may be magnetized so that a part of the cylindrical portion 151 is configured as each of the outer magnetic poles 152A and 152B.

[0047] The output unit 153 transmits the rotational power generated in the plurality of outer magnetic poles 152A and 152B to the flow path forming unit 20. The output unit 153 rotates about the rotation axis 141B of the drive motor 141. The output unit 153 has a rotating portion 153A and an outer shaft 153B.

[0048] The rotating portion 153A is a bottomed cylindrical portion in the output unit 153 having a diameter substantially the same as that of the cylindrical portion 151. The cylindrical portion 151 is fixed to the opening side of the rotating portion 153A. The outer shaft 153B is a hollow cylindrical portion in the output unit 153 having a smaller diameter than the rotating portion 153A. The outer shaft 153B is formed to have a length reaching the flow path forming unit 20 in the axial direction. The outer shaft 153B becomes a portion that outputs the rotational power of the outer magnet axis 150.

[0049] A first bearing 155 is disposed at the connecting portion between the rotating portion 153A and the outer shaft 153B. That is, the outer shaft 153B is inserted into the first bearing 155. Thereby, the outer magnet axis 150 is rotatably supported.

[0050] The friction ring 154 is an annular component for stopping the rotation of the outer magnet axis 150 by the selector 170. The friction ring 154 is fixed to the bottom portion 153C of the rotating portion 153A on the side opposite to the side of the cylindrical portion 151.

[0051] The pole piece shaft 160 is an output shaft that is rotatably supported on the rotation shaft 141B of the drive shaft 141A. The pole piece shaft 160 rotates by modulating the magnetic flux between the multiple inner magnetic poles 142A and 142B of the inner magnet shaft 140 and the multiple outer magnetic poles 152A and 152B of the outer magnet shaft 150.

[0052] The pole piece shaft 160 has a support portion 161, a plurality of magnetic material portions 162, a friction ring 163, an output shaft 164, and an inner shaft 165.

[0053] The support portion 161 is a component that supports the multiple magnetic body portions 162 and the output shaft 164. The support portion 161 is a bottomed cylindrical component whose diameter is smaller than the cylindrical portion 151 of the outer magnet shaft 150 and larger than the inner magnet shaft 140. The support portion 161 is, for example, a metal component. The opening side of the support portion 161 is directed toward the inner magnet shaft 140, and the bottom side is directed toward the rotating portion 153A of the outer magnet shaft 150.

[0054] The multiple magnetic parts 162 are pole pieces formed from a soft magnetic material such as an iron-based metal. The magnetic parts 162 are formed in a rod shape that extends along the axial direction. The multiple magnetic parts 162 are fixed to the open end of the support part 161. In this embodiment, there are 25 magnetic parts 162.

[0055] The multiple magnetic body portions 162 are positioned radially between the multiple inner magnetic poles 142A, 142B and the multiple outer magnetic poles 152A, 152B, and are also arranged on the outer circumference of the multiple inner magnetic poles 142A, 142B. Furthermore, the multiple magnetic body portions 162 are arranged adjacent to each other at a predetermined interval. In other words, the multiple magnetic body portions 162 are arranged in a birdcage-like manner. The axial length of the magnetic body portion 162 may be the same as, or different from, the axial length of the outer magnetic poles 152A, 152B of the outer magnet shaft 150.

[0056] The friction ring 163 is an annular component used by the selector 170 to stop the rotation of the pole piece shaft 160. The friction ring 163 is fixed to the side opposite to the support portion 161 in the multiple magnetic portion 162.

[0057] The output shaft 164 is a component that transmits the rotation of the support portion 161 to the inner shaft 165. One end of the output shaft 164 is screwed to the bottom portion of the support portion 161. The output shaft 164 is positioned in the hollow portion of the outer shaft 153B of the output portion 153.

[0058] A second bearing 166 is positioned between the outer shaft 153B of the outer magnet shaft 150 and the output shaft 164. In other words, the output shaft 164 is inserted into the second bearing 166. This allows the pole piece shaft 160 and the outer magnet shaft 150 to be rotatably supported relative to each other.

[0059] The inner shaft 165 is a component that receives rotational power from the output shaft 164. One end of the inner shaft 165 is fixed to the output shaft 164 and is positioned in the hollow portion of the outer shaft 153B. The other end of the inner shaft 165 is formed to reach the flow path forming portion 20 in the axial direction and to reach a position deeper than the outer shaft 153B. The inner shaft 165 is the part that outputs the rotational power of the pole piece shaft 160.

[0060] Hereafter, the rotating body 10A will be defined as the structure in which the inner magnetic poles 142A and 142B of the inner magnet shaft 140, the outer magnetic poles 152A and 152B of the outer magnet shaft 150, and the magnetic body parts 162 of the pole piece shaft 160 are arranged concentrically around the rotation axis 141B.

[0061] The selector 170 moves its axial position relative to the outer magnet shaft 150 and the pole piece shaft 160 based on the control commands from the selector control circuit. As a result, the selector 170 selectively stops the rotation of either the outer magnet shaft 150 or the pole piece shaft 160.

[0062] The selector 170 includes a coil 171, a yoke 172, a switching member 173, friction rings 174 and 175, and a permanent magnet 176.

[0063] The coil 171 is located on the outside of the housing 130 and is an annular DC coil surrounding the housing 130. The coil 171 is provided near the first rotation restricting portion 173A of the switching member 173. The coil 171 is switched by the selector control circuit between flowing current in a predetermined first current direction and flowing current in the opposite second current direction.

[0064] The yoke 172 is a magnetic component that surrounds the coil 171 and generates a magnetic path inside it when current is supplied to the coil 171. The yoke 172 together with the coil 171 constitutes an electromagnetic coil. The yoke 172 is fixed to the housing 130. The yoke 172 is an annular member made of iron with a groove shape recessed radially outward. The coil 171 is housed inside the groove shape of the yoke 172.

[0065] The switching member 173 is a hollow cylindrical component positioned on the outer circumference of the outer magnet shaft 150. The switching member 173 is also positioned to be movable along the axial direction. The switching member 173 has a first rotation restricting portion 173A and a second rotation restricting portion 173B.

[0066] The first rotation restricting portion 173A restricts the rotation of the outer magnet shaft 150. The first rotation restricting portion 173A is an annular portion formed such that the opening end on the flow path forming portion 20 side of the switching member 173 extends radially inward in the axial direction. Therefore, the first rotation restricting portion 173A is positioned opposite the rotating portion 153A of the outer magnet shaft 150 in the axial direction.

[0067] The second rotation restricting portion 173B restricts the rotation of the pole piece shaft 160. The second rotation restricting portion 173B is an annular portion of the switching member 173 formed such that the open end on the motor control board 120 side extends radially inward in the axial direction. Therefore, the second rotation restricting portion 173B is positioned in the axial direction opposite to each of the outer magnetic poles 152A, 152B of the outer magnet shaft 150 and each of the magnetic material portions 162 of the pole piece shaft 160.

[0068] The first rotation restricting unit 173A and the second rotation restricting unit 173B may be integrated with the switching member 173, or they may be configured as separate units.

[0069] The friction ring 174 is an annular component used by the selector 170 to stop the rotation of the outer magnet shaft 150. The friction ring 174 is fixed to the first opposing surface 173C of the first rotation restricting section 173A, which faces the rotating section 153A. The friction ring 174 is also positioned opposite the friction ring 154 of the outer magnet shaft 150. When the selector 170 moves axially, the friction ring 174 of the selector 170 engages with or creates friction with the friction ring 154 of the outer magnet shaft 150. As a result, the selector 170 stops the rotation of the outer magnet shaft 150.

[0070] The friction ring 175 is an annular component used by the selector 170 to stop the rotation of the pole piece shaft 160. The friction ring 175 is fixed to the second opposing surface 173D of the second rotation restricting section 173B, which faces each magnetic section 162. The friction ring 175 is also positioned opposite the friction ring 163 of the pole piece shaft 160. When the selector 170 moves axially, the friction ring 175 of the selector 170 engages with or creates friction with the friction ring 163 of the pole piece shaft 160. As a result, the selector 170 stops the rotation of the pole piece shaft 160.

[0071] The permanent magnet 176 is a selector magnetic material. The permanent magnet 176 is fixed to the side surface located on the outer diameter side of the first rotation restricting portion 173A. The permanent magnet 176 is arranged such that either the south pole or the north pole faces radially outward. In this embodiment, for example, the permanent north pole 176A is directed radially inward, and the permanent south pole 176B is directed radially outward. Also, four permanent magnets 176 are arranged, for example, at an angular pitch of 90° in the circumferential direction.

[0072] The holder 180 is a metal, disc-shaped component that separates the magnetic gear section 10 from the flow path forming section 20. The open end 133 of the housing 130 is fixed to the side of the holder 180 facing the motor control board 120. The holder 180 may be made of resin, for example.

[0073] The holder 180 has a projection 181 through which the rotation center portion, through which the rotation shaft 141B passes, is thickened in the axial direction, and a through hole 182 through which the projection 181 penetrates in the axial direction. The first rotation restricting portion 173A of the selector 170 is located in the space created by the axial height of the projection 181. The first rotation restricting portion 173A is movable in the axial direction within this space.

[0074] The outer shaft 153B of the outer magnet shaft 150 passes through the through hole 182. A second bearing 166 is positioned on the side of the through hole 182 that faces the inner magnet shaft 140.

[0075] A first groove 183 is formed along the axial direction on the outer circumferential wall of the protrusion 181. A second groove 177 is formed along the axial direction on the portion of the first rotation restricting portion 173A of the selector 170 that faces the first groove 183. A key 184 is inserted into the slit formed by the first groove 183 and the second groove 177. As a result, the rotation of the selector 170 is restricted by the key 184 catching on the protrusion 181.

[0076] The magnetic sensor 190 is a sensor that detects the rotation of the outer magnet shaft 150 and the pole piece shaft 160. The magnetic sensor 190 detects the change in magnetic flux density and its magnitude that occurs when either the outer magnet shaft 150 or the pole piece shaft 160 rotates.

[0077] The magnetic sensor 190 has a detection unit 191. The detection unit 191 generates a detection signal based on the change in magnetic flux density received from the outside and its magnitude. The detection unit 191 is configured as a detection element such as a Hall element or a magnetoresistive element.

[0078] The magnetic sensor 190 is positioned to be affected by the magnetic flux of either or both of the outer magnetic poles 152A, 152B of the outer magnet shaft 150 and the magnetic material parts 162 of the pole piece shaft 160. In this embodiment, the magnetic sensor 190 is positioned to be affected by the magnetic flux of both the outer magnetic poles 152A, 152B and the magnetic material parts 162.

[0079] In other words, the detection unit 191 is located on the outside of the rotating body 10A. Specifically, the detection unit 191 is located in the outer peripheral region 10B, which is the radial projection of the rotating body 10A, and within the axial range of the rotation axis 141B. As a result, the detection unit 191 is located in a position where the change in magnetic flux density and its magnitude are large, so the rotation detection accuracy can be improved.

[0080] The magnetic sensor 190 includes, in addition to the detection unit 191, a circuit board on which the detection unit 191 is mounted, a housing for the circuit board, and terminals for electrical connection to external devices. In this embodiment, the housing for the magnetic sensor 190 is fixed to the case 100. The magnetic sensor 190 is also electrically connected to the motor control board 120.

[0081] Furthermore, the magnetic sensor 190 does not have to be a finished product. For example, the magnetic sensor 190 may be a circuit board different from the motor control board 120 that is mounted on the case 100.

[0082] The flow path forming section 20 changes the valve opening degree based on the rotational power of the magnetic gear section 10. The flow path forming section 20 includes a block section 200, a first valve chamber 210, a first valve body 220, a second valve chamber 230, and a second valve body 240.

[0083] The block portion 200 constitutes the main body of the flow path forming portion 20. The block portion 200 is formed from, for example, a cast material using an Al-Si-Mg aluminum alloy. One end of the block portion 200 is fixed to the holder 180 and the open end 101 of the case. The block portion 200 may be a hollow rectangular parallelepiped, similar to the case 100, or it may be in other shapes such as cylindrical or prismatic. A sealing material such as an O-ring or gasket is appropriately placed between the block portion 200, the holder 180, and the case 100.

[0084] The block portion 200 has a first valve chamber 210, a second valve chamber 230, a first hole 201, and a second hole 202. The first valve chamber 210 and the second valve chamber 230 are spaces formed inside the block portion 200. The second valve chamber 230 is formed on the side of the magnetic gear portion 10 that the first valve chamber 210 is formed on in the axial direction.

[0085] The first hole 201 is a hole that penetrates the block portion 200 axially between the first valve chamber 210 and the second valve body 240. The first hole 201 houses the connecting screw 203 and a part of the first valve body 220. The rest of the first valve body 220 is housed in the first valve chamber 210.

[0086] The second hole 202 is a hole that penetrates axially between the magnetic gear portion 10 of the block portion 200 and the second valve chamber 230. The outer shaft 153B of the outer magnet shaft 150 is inserted into the second hole 202.

[0087] The first valve chamber 210 is connected to two ports 211 and 212 formed radially. One of the ports 211 and 212 corresponds to an inflow port from the outside into the first valve chamber 210, and the other corresponds to an outflow port from the first valve chamber 210 to the outside.

[0088] The first valve body 220 is connected to the connecting screw 203. The connecting screw 203 is screwed to the inner shaft 165 of the pole piece shaft 160. The inner shaft 165 passes through the second valve body 240 in the axial direction.

[0089] The connecting screw 203 is prevented from rotating by its shape, such as protrusions and other components, while allowing for axial movement. Therefore, the connecting screw 203 converts the rotation of the inner shaft 165 into axial movement. The first valve body 220 changes the valve opening degree by moving axially in conjunction with the axial movement of the connecting screw 203. The first valve body 220 operates, for example, as an expansion valve.

[0090] The second valve chamber 230 is connected to two ports 231 and 232 formed radially. One of the ports 231 and 232 corresponds to an inflow port from the outside into the second valve chamber 230, and the other corresponds to an outflow port from the second valve chamber 230 to the outside. As an example, a hose 233 is shown connected to port 231.

[0091] The second valve body 240 is housed in the second valve chamber 230. The second valve body 240 is connected to the outer shaft 153B of the outer magnet shaft 150. The second valve body 240 rotates in conjunction with the rotation of the outer magnet shaft 150, thereby changing the valve opening for each port 231, 232. The second valve body 240 operates, for example, as a steam pressure regulating valve.

[0092] The second valve body 240 may be configured to change the valve opening degree by moving axially in accordance with the rotation of the outer magnet shaft 150, similar to the first valve body 220. Similarly, the first valve body 220 may be configured to change the valve opening degree by rotating in accordance with the rotation of the pole piece shaft 160, similar to the second valve body 240.

[0093] <Axis Switching and Holding Function> Next, the switching of rotation of the pole piece shaft 160 and the outer magnet shaft 150, and the holding function of the selector 170 will be explained. The rotation control of each shaft 150 and 160 is performed by the selector control circuit section of the motor control board 120.

[0094] First, let's explain the case where the rotation of the outer magnet shaft 150 is stopped while the pole piece shaft 160 is rotated. This is a state in which the output of rotational power from the pole piece shaft 160 is permitted, while the output of rotational power from the outer magnet shaft 150 is restricted.

[0095] First, as shown in Figure 3, the selector control circuit section supplies current in the first current direction to the coil 171. The first current direction corresponds, for example, to the forward direction of the coil 171. As a result, according to the right-hand rule, a magnetic flux in the first magnetic flux direction is generated in the yoke 172. Due to the north-south pole orientation of the permanent magnet 176 fixed to the selector 170, the permanent magnet 176 is attracted to the direction in which the magnetic flux direction of the yoke 172 coincides.

[0096] For example, if the south pole of the permanent magnet 176 is located radially outward, the direction of the magnetic flux around the permanent magnet 176 will be radially from the inside to the outside. On the other hand, the first magnetic flux direction of the magnetic flux at the first end 172A of the yoke 172 on the magnetic gear section 10 side will be radially from the inside to the outside. Also, the first magnetic flux direction of the magnetic flux at the second end 172B of the yoke 172 on the flow path forming section 20 side will be radially from the outside to the inside. Therefore, the direction of the magnetic flux of the permanent magnet 176 of the selector 170 coincides with the direction of the magnetic flux at the first end 172A of the yoke 172. Thus, the selector 170 is attracted to the first end 172A of the yoke 172 and moves axially from the flow path forming section 20 side to the magnetic gear section 10 side.

[0097] As the selector 170 moves, the friction ring 174 provided on the first opposing surface 173C of the selector 170 comes into contact with the friction ring 154 provided on the rotating portion 153A of the outer magnet shaft 150. This prevents the outer magnet shaft 150 from rotating.

[0098] Here, the selector 170 moves to a first selector position in the axial direction relative to the housing 130 when the rotation of the outer magnet shaft 150 is stopped by energizing the coil 171. In the first selector position in the axial direction, the selector 170 forms a first magnetic circuit 178A between the yoke 172 and the permanent magnet 176. Furthermore, the selector 170 maintains the first selector position in the axial direction by being attracted to the yoke 172 by the magnetic force of the permanent magnet 176.

[0099] The selector control circuit unit energizes the coil 171 only for a certain period of time until the movement of the selector 170 is complete. When the selector control circuit unit stops energizing the coil 171, the electromagnetic force from the yoke 172 to the permanent magnet 176 stops. However, the magnetic force of the permanent magnet 176 of the selector 170 continues to act as an attractive force on the yoke 172. Therefore, even when the energization of the coil 171 is stopped, the rotation of the outer magnet shaft 150 can be kept stopped, and the first selector position of the selector 170 in the axial direction can be maintained. The contact state of the friction rings 154 and 174 is also maintained. This is the holding function of the selector 170 when the rotation of the outer magnet shaft 150 is stopped.

[0100] On the other hand, when the selector 170 moves to the first selector position, the friction ring 175 of the selector 170 and the friction ring 163 of the pole piece shaft 160 become separated. As a result, the rotation of the pole piece shaft 160 is not hindered by the selector 170. In addition, the pole piece shaft 160 becomes rotatable by the driving force transmitted from the inner magnet shaft 140.

[0101] Specifically, when the selector control circuit drives the drive motor 141 of the inner magnet shaft 140, the rotational power generated by the drive motor 141 is transmitted to the outer magnet shaft 150 and the pole piece shaft 160 through magnetic interactions between each inner magnetic pole 142A, 142B, each magnetic material part 162, and each outer magnetic pole 152A, 152B.

[0102] At this time, the rotation of the outer magnet shaft 150 is stopped, but the pole piece shaft 160 rotates in the same direction as the inner magnet shaft 140, reduced by a reduction ratio corresponding to the pole ratio. In this embodiment, the inner magnetic poles 142A and 142B are one pole pair, and the magnetic material portion 162 has 25 poles, so the reduction ratio is 1 / 25.

[0103] The rotational power of the pole piece shaft 160 is then transmitted to the first valve body 220 via the output shaft 164 and the inner shaft 165. As a result, the first valve body 220 changes the valve opening. In contrast, since the rotation of the outer magnet shaft 150 has stopped, the opening of the second valve body 240 does not change.

[0104] Next, we will explain the case where the rotation of the pole piece shaft 160 is stopped while the outer magnet shaft 150 is rotated. This is a state in which the output of rotational power by the outer magnet shaft 150 is permitted, while the output of rotational power by the pole piece shaft 160 is restricted.

[0105] In this case, as shown in Figure 4, the selector control circuit section flows a current in the second current direction, which is opposite to the first current direction, through the coil 171. As a result, a magnetic flux in the second magnetic flux direction is generated in the yoke 172 according to the right-hand rule. The first magnetic flux direction of the magnetic flux in the first magnetic circuit 178A and the second magnetic flux direction of the magnetic flux in the second magnetic circuit 178B, which will be described later, are in opposite directions.

[0106] Furthermore, the second magnetic flux direction at the first end 172A of the yoke 172 is from the radial outside to the inside, and the second magnetic flux direction at the second end 172B of the yoke 172 is from the radial inside to the outside. Therefore, the direction of the magnetic flux of the permanent magnet 176 of the selector 170 coincides with the direction of the magnetic flux at the second end 172B of the yoke 172. Consequently, the selector 170 is attracted to the second end 172B of the yoke 172 and moves axially from the magnetic gear section 10 side to the flow path forming section 20 side.

[0107] As the selector 170 moves, the friction ring 175 provided on the second opposing surface 173D of the selector 170 comes into contact with the friction rings 163 provided on each magnetic part 162 of the pole piece shaft 160. This prevents the pole piece shaft 160 from rotating.

[0108] Here, the selector 170 moves to a second selector position in the axial direction relative to the housing 130 when the rotation of the pole piece shaft 160 is stopped by energizing the coil 171. In the second selector position in the axial direction, the selector 170 forms a second magnetic circuit 178B between the yoke 172 and the permanent magnet 176. Furthermore, the selector 170 maintains the second selector position in the axial direction by being attracted to the yoke 172 by the magnetic force of the permanent magnet 176.

[0109] Even if the selector control circuit stops supplying power to the coil 171, the magnetic force of the permanent magnet 176 of the selector 170 continues to act as an attractive force on the yoke 172. Therefore, the rotation of the pole piece shaft 160 can be kept stopped, and the second selector position of the selector 170 in the axial direction can be maintained. The contact state of the friction rings 163 and 175 is also maintained. This is the holding function of the selector 170 when the rotation of the pole piece shaft 160 is stopped. In this way, the holding function of the selector 170 makes it possible to maintain the position of the selector 170 in the axial direction at either the first selector position or the second selector position.

[0110] On the other hand, when the selector 170 moves to the second selector position, the friction ring 174 of the selector 170 and the friction ring 154 of the outer magnet shaft 150 become separated. As a result, the rotation of the outer magnet shaft 150 is not hindered by the selector 170. In addition, the outer magnet shaft 150 becomes rotatable by the driving force transmitted from the inner magnet shaft 140.

[0111] The rotational power generated by the rotation of the drive motor 141 is transmitted to the outer magnet shaft 150 and the pole piece shaft 160 through magnetic interactions between each inner magnetic pole 142A, 142B, each magnetic body part 162, and each outer magnetic pole 152A, 152B. At this time, the rotation of the pole piece shaft 160 is stopped, but the outer magnet shaft 150 rotates in the opposite direction to the inner magnet shaft 140, with a reduction ratio corresponding to the pole ratio. In this embodiment, the inner magnetic poles 142A and 142B are one pole pair, and the outer magnetic poles 152A and 152B are 24 pole pairs, so the reduction ratio is 1 / 24.

[0112] The rotational power of the outer magnet shaft 150 is then transmitted to the second valve body 240 via the outer shaft 153B. As a result, the second valve body 240 changes the valve opening. In contrast, since the rotation of the pole piece shaft 160 has stopped, the opening of the first valve body 220 does not change.

[0113] <Axis Rotation Detection> Next, the detection of rotation of each axis 150 and 160 by the magnetic sensor 190 will be explained. First, due to the rotation of the outer magnet axis 150 or the pole piece axis 160, leakage magnetic flux is generated on the outside of the outer magnet axis 150. The magnetic sensor 190 outputs a detection signal based on the change in magnetic flux density and its magnitude to the determination circuit section of the motor control board 120.

[0114] As shown in Figure 5, the outer magnetic poles 152A and 152B are arranged alternately in the circumferential direction. When the outer magnet shaft 150 rotates in the opposite direction to the inner magnet shaft 140, the magnetic flux density outside the outer magnetic poles 152A and 152B changes due to the rotation of the outer magnet shaft 150. Therefore, the magnetic sensor 190 can detect the change in magnetic flux density accompanying the rotation of the outer magnet shaft 150. Note that Figure 5 corresponds to the II-II cross section in Figure 1. The same applies to Figure 7.

[0115] As shown in Figure 6, the detection signal from the magnetic sensor 190 is a waveform signal in which the magnetic flux density and its magnitude (amplitude) change according to the rotational position of the outer magnet shaft 150. By knowing in advance the change in magnetic flux density and its magnitude (amplitude) associated with the rotation of the outer magnet shaft 150, a threshold value for the amplitude can be set. For example, the threshold value for the maximum amplitude associated with the rotation of the outer magnet shaft 150 can be set as the first threshold value.

[0116] As shown in Figure 7, when the pole piece shaft 160 rotates in the same direction as the inner magnet shaft 140, the positional relationship between each outer magnetic pole 152A, 152B of the outer magnet shaft 150 and each magnetic part 162 of the pole piece shaft 160 changes periodically. Since the magnetic part 162 is made of magnetic material, its magnetoresistance changes periodically with respect to the magnetic field generated by each outer magnetic pole 152A, 152B. Therefore, the magnetic flux density generated outside the outer magnet shaft 150 also changes periodically.

[0117] As shown in Figure 8, the maximum amplitude of the magnetic flux density change due to the rotation of the pole piece shaft 160 is smaller than when the outer magnet shaft 150 rotates. Therefore, a threshold value for the maximum amplitude of the magnetic flux density change due to the rotation of the pole piece shaft 160 is set as the second threshold value.

[0118] The first and second thresholds are pre-set in the determination circuit section of the motor control board 120. Since the amplitude of the change in magnetic flux density when the outer magnet shaft 150 rotates is greater than the amplitude of the change in magnetic flux density when the pole piece shaft 160 rotates, each threshold is set to satisfy the condition that the first threshold > the second threshold.

[0119] The determination circuit unit acquires the detection signal from the magnetic sensor 190. The determination circuit unit then compares the amplitude of the magnetic flux density change included in the detection signal with each threshold value. If the maximum amplitude of the magnetic flux density change is less than the second threshold value, the determination circuit unit determines that neither the pole piece shaft 160 nor the outer magnet shaft 150 is rotating. If the second threshold value is less than the maximum amplitude of the magnetic flux density change, the determination circuit unit determines that the pole piece shaft 160 is rotating and the outer magnet shaft 150 is not rotating. If the first threshold value is less than the maximum amplitude of the magnetic flux density change, the determination circuit unit determines that the outer magnet shaft 150 is rotating and the pole piece shaft 160 is not rotating.

[0120] Furthermore, the determination circuit unit obtains control information from the selector control circuit unit regarding whether to permit or prohibit the rotation of the outer magnet shaft 150 and the pole piece shaft 160. The determination circuit unit then determines whether the rotating shaft matches the rotation detection result based on the control information. The determination circuit unit determines that the operation of the flow path forming unit 20 is normal if the control information and the rotation detection match. On the other hand, the determination circuit unit determines that the operation of the flow path forming unit 20 is abnormal if the control information and the rotation detection do not match.

[0121] As described above, in this embodiment, we focus on the fact that the maximum amplitude of the magnetic flux density change outside the outer magnet shaft 150 is different for the outer magnet shaft 150 and the pole piece shaft 160, and we have configured the system to detect the magnetic flux density change and its magnitude using a single detection unit 191. Therefore, since it is not necessary to provide a magnetic sensor 190 and a sensor output mechanism for both shafts 150 and 160, we can suppress an increase in the size of the power transmission device 1.

[0122] Furthermore, the magnetic sensor 190 detects the rotation of each axis 150 and 160 as a continuously changing change in magnetic flux density and its magnitude. Therefore, it is possible to ensure rotation detection accuracy compared to intermittent rotation detection for each rotation.

[0123] (Second Embodiment) This embodiment mainly describes the differences from the first embodiment. As shown in Figure 9, in this embodiment, the magnetic sensor 190 is positioned in the overhang range 10C of the outer peripheral region 10B of the rotating body 10A.

[0124] The overhang range is the range in which the outer magnetic poles 152A and 152B protrude toward the flow channel forming section 20 from the inner magnetic pole range 142C of the inner magnetic poles 142A and 142B along the axial direction of the rotation axis 141B. The overhang range is the axial range in which the outer magnetic poles 152A and 152B and the inner magnetic poles 142A and 142B do not overlap in the radial direction. In other words, it is the axial range in which the outer magnetic pole range 152C and the inner magnetic pole range 142C of the outer magnetic poles 152A and 152B do not overlap in the radial direction. In the example shown in Figure 9, the overhang range is set in the axial direction on the side of the outer magnetic poles 152A and 152B toward the flow channel forming section 20.

[0125] When the magnetic sensor 190 detects a change in magnetic flux density due to the rotation of the inner magnet shaft 140, the change in magnetic flux density of the inner magnet shaft 140 will overlap with the change in magnetic flux density of the pole piece shaft 160 and the outer magnet shaft 150. This may hinder the change in magnetic flux density that is necessary for the rotation of the pole piece shaft 160 and the outer magnet shaft 150. To avoid this, the magnetic sensor 190 is positioned in the overhang range 10C described above so as not to be affected by the magnetic fields of the inner magnetic poles 142A and 142B of the inner magnet shaft 140.

[0126] This eliminates the influence of the magnetic fields of the inner magnetic poles 142A and 142B of the inner magnet shaft 140. Therefore, the detection accuracy of changes in magnetic flux density associated with the rotation of the pole piece shaft 160 and the outer magnet shaft 150 can be improved.

[0127] (Third Embodiment) This embodiment mainly describes the parts that differ from the first embodiment. As shown in Figure 10, in this embodiment, the magnetic sensor 190 is positioned in the axial region 10D obtained by projecting the rotating body 10A in the axial direction of the rotating shaft 141B on the outside of the rotating body 10A. Figure 10 shows an example of an overhang range in which the outer magnetic poles 152A and 152B protrude toward the motor control board 120 side from the inner magnetic poles 142A and 142B along the axial direction of the rotating shaft 141B, and the outer magnetic poles 152A and 152B and the inner magnetic poles 142A and 142B do not overlap in the radial direction.

[0128] The axial region 10D has two parts relative to the rotating body 10A: one on the motor control board 120 side and the other on the holder 180 side. The area on the holder 180 side has less space to place the magnetic sensor 190. Also, because it is far from the inner magnetic poles 142A, 142B, the magnetic body part 162, and the outer magnetic poles 152A, 152B, it is less susceptible to the influence of the magnetic field. Therefore, the magnetic sensor 190 is placed in the axial region 10D on the motor control board 120 side.

[0129] Furthermore, the detection unit 191 of the magnetic sensor 190 is positioned on a circle of a virtual pole piece drawn in the axial region 10D by the rotation of the multiple magnetic body parts 162 in the axial region 10D. The magnetic sensor 190 is mounted, for example, on the motor control board 120. Alternatively, the magnetic sensor 190 may be mounted on the housing 130.

[0130] The arrangement of the magnetic sensor 190 described above allows the detection unit 191 to be positioned closer to the outer magnet shaft 150 and the pole piece shaft 160, while being less affected by the inner magnet shaft 140. Therefore, the same effects as in the second embodiment can be obtained.

[0131] As another example, as shown in Figure 11, the magnetic sensor 190 may be positioned on a virtual outer circle drawn in the axial region 10D by the rotation of each outer magnetic pole 152A, 152B of the outer magnet shaft 150 in the axial region 10D.

[0132] As another example, as shown in Figure 12, the magnetic sensor 190 may be positioned on a virtual intermediate circle between the pole piece circle and the outer circle in the axial region 10D.

[0133] (Fourth Embodiment) This embodiment mainly describes the differences from the first embodiment. As shown in Figure 13, in this embodiment, two magnetic sensors 190 are installed in the case 100. The configuration of the two magnetic sensors 190 is the same.

[0134] The detection unit of one magnetic sensor 190 is designated as the first detection unit 191. The detection unit of the other magnetic sensor 190 is designated as the second detection unit 192. The first detection unit 191 and the second detection unit 192 are as shown in the above embodiments. The second detection unit 192 generates a second detection signal based on the change in magnetic flux density received from the outside and its magnitude, similar to the first detection unit 191.

[0135] For example, the first detection unit 191 and the second detection unit 192 are housed in separate cases. Alternatively, the first detection unit 191 and the second detection unit 192 may be housed in a single case. In other words, the magnetic sensor 190 only needs to have at least two detection units 191 and 192.

[0136] The first detection unit 191 and the second detection unit 192 are arranged in the outer peripheral region 10B of the rotating body 10A. Furthermore, the first detection unit 191 is positioned to correspond to the outer N pole 152A, and the second detection unit 192 is positioned to correspond to the outer S pole 152B.

[0137] Specifically, the first detection unit 191 and the second detection unit 192 are arranged along the circumference in the outer peripheral region 10B such that they are adjacent to each other, corresponding to a pitch of one magnetic pole between adjacent outer N poles 152A and outer S poles 152B. In other words, the first detection unit 191 and the second detection unit 192 are arranged at a pitch of 1 / 2 pole in the circumference.

[0138] Figure 14 is a stop-motion diagram showing the movement of each part when the pole piece shaft 160 is fixed and the outer magnet shaft 150 is rotated, and the inner magnet shaft 140 is rotated in 60° increments. When the outer magnet shaft 150 rotates, if the inner magnet shaft 140 rotates 60° counterclockwise, the outer magnet shaft 150 rotates 2.5° clockwise.

[0139] As described above, the reduction ratio of the outer magnet shaft 150 is 1 / 24, so when the inner magnet shaft rotates once (360°), the outer magnet shaft 150 rotates by one pole (15° = 360° ÷ 24 pole pairs). In this way, the outer magnet shaft 150 rotates in the opposite direction to the inner magnet shaft 140 with a reduction ratio of 1 / 24 for each rotation.

[0140] Figure 15 is a step-by-step diagram showing the movement of each part when the outer magnet shaft 150 is fixed and the pole piece shaft 160 is rotated, and the inner magnet shaft 140 is rotated in 60° increments. When the pole piece shaft 160 rotates, if the inner magnet shaft 140 rotates 60° counterclockwise, the pole piece shaft 160 also rotates 2.4° counterclockwise.

[0141] As described above, the reduction ratio of the pole piece shaft 160 is 1 / 25, so when the inner magnet shaft 140 rotates once, the pole piece shaft 160 rotates by one pole (14.4° = 360° ÷ 25 poles). In this way, the pole piece shaft 160 rotates in the same direction as the inner magnet shaft 140 with a reduction ratio of 1 / 25 for each rotation.

[0142] Next, the rotation detection of the shaft by the two detection units 191 and 192 will be described. The first detection unit 191 and the second detection unit 192 are affected by the combined magnetic fields at the respective positions of the inner magnet shaft 140, the outer magnet shaft 150, and the pole piece shaft 160. In particular, the inner magnetic poles 142A and 142B of the inner magnet shaft 140 and the outer magnetic poles 152A and 152B of the outer magnet shaft 150 are permanent magnets and possess magnetism themselves, so their positional relationship with each of the detection units 191 and 192 greatly affects the detection signal.

[0143] First, let's assume that the two detection units 191 and 192 are located at the first sensor position shown in Figure 16. Note that cross-sectional hatching is omitted in Figure 16.

[0144] The first sensor position is the position where the stopped pole piece shaft 160 or outer magnet shaft 150 is magnetically neutral with respect to the two detection units 191 and 192. In other words, with the outer magnet shaft 150 stopped, the two detection units 191 and 192 are located on the extension of the boundary between adjacent outer magnetic poles 152A and 152B in the radial direction.

[0145] The first row of Figure 17 shows the detection signals of the first detection unit 191 and the second detection unit 192 when the pole piece shaft 160 is fixed and the outer magnet shaft 150 rotates at the first sensor position.

[0146] In Figure 16, the first detection unit 191 and the second detection unit 192 are greatly influenced by the magnetism of the inner magnetic poles 142A and 142B of the inner magnet shaft 140 and the outer magnetic poles 152A and 152B of the outer magnet shaft 150. However, at the position of the first detection unit 191, the N-S poles of the outer S pole 152B of the outer magnet shaft 150 and the inner S pole 142B of the inner magnet shaft 140 rotate in the same phase as the inner magnet shaft 140 and the outer magnet shaft 150 rotate.

[0147] Therefore, as shown in the first row of Figure 17, the amplitude of the first detection signal of the first detection unit 191 increases. On the other hand, at the position of the second detection unit 192, the outer magnetic poles 152A and 152B of the outer magnet shaft 150 have a phase difference of 1 / 2 pole. Therefore, the magnetic force of the outer magnet shaft 150 reverses and cancels out, and the amplitude of the second detection signal of the second detection unit 192 decreases.

[0148] Since the magnetic force of the inner magnetic poles 142A and 142B of the inner magnet shaft 140 fluctuates in a cycle of 360°, the positional difference between the first detection unit 191 and the second detection unit 192 is 15°, and the phase difference of the magnetic force change is 15° / 360°.

[0149] In contrast, the outer magnet shaft 150 rotates in a period of 15°, and the arrangement of the first detection unit 191 and the second detection unit 192 is such that the distance between them is 1 / 2 pole, which is 7.5°, resulting in a phase reversal. That is, the first detection unit 191 and the second detection unit 192 detect the magnetic force of the inner magnet shaft 140 in roughly the same phase, while detecting the magnetic force of the outer magnet shaft 150 in opposite phase.

[0150] By utilizing this characteristic, if the difference between the output of the first detection unit 191 (amplitude of the first detection signal) and the output of the second detection unit 192 (amplitude of the second detection signal) is taken, the amplitude decreases slightly as shown in the second row of Figure 17, but the influence of the magnetic force of the inner magnet shaft 140 is canceled out. On the other hand, if the output of the first detection unit 191 and the output of the second detection unit 192 are added together, as shown in the third row of Figure 17, the influence of the magnetic force of the outer magnet shaft 150 becomes larger. In this way, the magnetic force change of the pole piece shaft 160, which has a small output, can be extracted.

[0151] Furthermore, when taking the difference between the output of the first detection unit 191 and the output of the second detection unit 192, this includes both cases: subtracting the amplitude of the second detection signal from the amplitude of the first detection signal, and subtracting the amplitude of the first detection signal from the amplitude of the second detection signal.

[0152] Next, the first row of Figure 18 shows the detection signals of the first detection unit 191 and the second detection unit 192 when the outer magnet shaft 150 is fixed and the pole piece shaft 160 is rotating at the first sensor position. Similar to the case of the first sensor position, the first detection unit 191 and the second detection unit 192 are continuously affected by the magnetic force of the outer magnetic poles 152A and 152B. However, since the first detection unit 191 and the second detection unit 192 are located at the magnetically neutral point of the outer magnetic poles 152A and 152B when the outer magnet shaft 150 is stopped, the detection signals are in phase and have no offset.

[0153] Therefore, when the difference between the output of the first detection unit 191 and the output of the second detection unit 192 is taken, the amplitude of the calculation result becomes almost zero, as shown in the second row of Figure 18. On the other hand, when the output of the first detection unit 191 and the output of the second detection unit 192 are added together, as shown in the third row of Figure 18, the amplitude of the calculation result doubles.

[0154] Next, let's assume that two detection units 191 and 192 are arranged at the second sensor position, as shown in Figure 19. Note that cross-sectional hatching is omitted in Figure 19.

[0155] The second sensor position is the position where the outer magnet shaft 150 or pole piece shaft 160 is stopped, and a biased magnetic force is generated for either the outer magnetic pole 152A or 152B with respect to the two detection units 191 and 192. In other words, with the outer magnet shaft 150 stopped, in the radial direction, for example, the first detection unit 191 is located on the extension of the outer N pole 152A, and the second detection unit 192 is located on the extension of the outer S pole 152B.

[0156] The first row of Figure 20 shows the detection signals of the first detection unit 191 and the second detection unit 192 when the pole piece shaft 160 is fixed and the outer magnet shaft 150 rotates at the second sensor position. The detection signals of the first detection unit 191 and the second detection unit 192 have approximately the same amplitude but different phases.

[0157] Therefore, taking the difference between the output of the first detection unit 191 and the output of the second detection unit 192 results in the waveform shown in the second row of Figure 20. Also, as with the first sensor position, the influence of the magnetic force of the inner magnet shaft 140 is canceled out. On the other hand, adding the output of the first detection unit 191 and the output of the second detection unit 192 results in the waveform shown in the third row of Figure 20.

[0158] Next, the first row of Figure 21 shows the detection signals of the first detection unit 191 and the second detection unit 192 when the outer magnet shaft 150 is fixed and the pole piece shaft 160 rotates at the second sensor position.

[0159] When the pole piece shaft 160 is fixed and the outer magnet shaft 150 rotates at the second sensor position, the first detection unit 191 and the second detection unit 192 continue to be affected by the magnetic force of the outer magnetic poles 152A and 152B while the outer magnet shaft 150 is stationary. In other words, the outer south pole 152B continuously provides a constant, unchanging magnetic force to the first detection unit 191, and the outer north pole 152A continuously provides a constant, unchanging magnetic force to the second detection unit 192.

[0160] As a result, as shown in the first row of Figure 21, each detection signal becomes an output of an AC component with a constant DC component. The difference from Figure 20 is that each detection signal is in phase and also contains a constant DC component offset. Therefore, when the difference between the output of the first detection unit 191 and the output of the second detection unit 192 is taken, the amplitude of the calculation result is approximately equal to the offset, as shown in the second row of Figure 21. On the other hand, when the output of the first detection unit 191 and the output of the second detection unit 192 are added together, the influence of the magnetic force of the outer magnet shaft 150 becomes large, as shown in the third row of Figure 21.

[0161] Therefore, the determination circuit compares the result of addition or subtraction of each detection signal shown in Figures 17, 18, 20, and 21 with a preset threshold. The threshold includes both cases where it is preset for addition and cases where it is preset for subtraction.

[0162] As a result, the determination circuit unit can determine whether the flow path forming unit 20 is operating normally or not based on the comparison result and the control information of the selector control circuit unit. The determination circuit unit may also determine rotation detection based on the results of both addition and subtraction calculations of each detection signal.

[0163] If the calculation result includes an offset, the judgment circuit can remove the offset using an electrical filter circuit to remove the DC component or a calculation formula to cancel out the DC component in the calculation. This allows the judgment circuit to extract only the AC component. Therefore, the judgment circuit can perform rotation detection using the calculation result from which the offset has been removed.

[0164] As described above, the same effects as in the first embodiment can be obtained even in a configuration using two detection units 191 and 192.

[0165] (Fifth Embodiment) This embodiment will mainly describe the parts that differ from the above embodiments. In this embodiment, the magnetic sensor 190 is positioned in a location that is affected by the magnetic flux from the selector magnetic material of the selector 170. The magnetic sensor 190 also detects the magnitude of the magnetic flux density according to the position of the selector 170 relative to the outer magnet shaft 150 and the pole piece shaft 160.

[0166] Furthermore, the drive torque of the drive motor 141 for the inner magnet shaft 140 is set to be greater than the rotational torque of the pole piece shaft 160 or the outer magnet shaft 150. If the rotational torque of the pole piece shaft 160 or the outer magnet shaft 150 becomes greater than the drive torque of the drive motor 141, the drive motor 141 will stop. The motor controller is configured to detect when the drive motor 141 has stopped.

[0167] Specifically, as shown in Figures 22 and 23, the magnetic sensor 190 is embedded in a recess 172C provided in the yoke 172. The recess 172C is a notch provided in the second end portion 172B of the yoke 172. For example, a part of the second end portion 172B of the recess 172C is recessed toward the magnetic gear portion 10 in the axial direction and also recessed toward the radially outward direction.

[0168] The sensitivity direction of the detection unit 191 of the magnetic sensor 190 is set to the radial direction. The magnetic sensor 190 detects the first or second magnetic flux direction of the magnetic flux generated in the first magnetic circuit 178A or the second magnetic circuit 178B, which is formed between the yoke 172 and the permanent magnet 176.

[0169] Next, the rotation detection of the outer magnet shaft 150 and the pole piece shaft 160 according to the axial position of the selector 170 will be described. First, when the rotation of the outer magnet shaft 150 is stopped and the pole piece shaft 160 is rotated by energizing the coil 171, a current in the first current direction flows through the coil 171 as described above. As a result, as shown in Figure 22, the selector 170 moves to the first selector position in the axial direction relative to the housing 130.

[0170] Furthermore, a first magnetic circuit 178A is formed between the yoke 172 and the permanent magnet 176. Therefore, the detection unit 191 of the magnetic sensor 190 detects the magnetic flux in the first magnetic flux direction generated in the first magnetic circuit 178A at the first selector position of the selector 170. In other words, the detection unit 191 detects the first magnetic flux direction of the magnetic flux generated inside the yoke 172 according to the first current direction.

[0171] Next, when the rotation of the pole piece shaft 160 is stopped by energizing the coil 171 and the outer magnet shaft 150 is rotated, a current in the second current direction flows through the coil 171, as shown in Figure 24. As a result, the selector 170 moves to the second selector position in the axial direction relative to the housing 130.

[0172] Furthermore, as shown in Figure 25, a second magnetic circuit 178B is configured. Therefore, the detection unit 191 of the magnetic sensor 190 detects the magnetic flux in the second magnetic flux direction generated in the second magnetic circuit 178B at the second selector position of the selector 170. In other words, the detection unit 191 detects the second magnetic flux direction of the magnetic flux generated inside the yoke 172 by the second current direction.

[0173] The determination circuit unit estimates the position of the selector 170 based on the direction of the magnetic flux acting on the magnetic sensor 190. Furthermore, since the drive motor 141 that drives the inner magnet shaft 140 is controlled by a motor controller, the determination circuit unit obtains information from the motor controller regarding the rotation status of the inner magnet shaft 140. Therefore, the determination circuit unit can indirectly determine whether the pole piece shaft 160 or the outer magnet shaft 150 is rotating based on the rotation of the inner magnet shaft 140 and the position of the selector 170. This determination may also be performed by an external device of the power transmission device 1.

[0174] Furthermore, the position of the recess 172C provided in the yoke 172 is not limited to the second end 172B, but can be in other locations. Also, since the magnetic sensor 190 only needs to be able to detect the magnetic flux corresponding to the axial position of the selector 170, the position of the magnetic sensor 190 is not limited to the recess 172C of the yoke 172. In other words, the magnetic sensor 190 is not limited to detecting the magnetic flux within the yoke 172.

[0175] As another example, the detection unit 191 of the magnetic sensor 190 may detect the magnitude of the magnetic flux density received from the permanent magnet 176 at the first selector position or the second selector position of the selector 170. That is, the detection unit 191 detects the magnitude of the magnetic flux density received from the permanent magnet 176 at the first selector position of the selector 170. Also, the detection unit 191 detects the magnitude of the magnetic flux density received from the permanent magnet 176 at the second selector position of the selector 170.

[0176] Here, the magnetic force of the permanent magnet 176 continues to act in the position where the selector 170 is held by the holding function of the selector 170. That is, a magnetic flux acts on the yoke 172 in the same direction as when the coil 171 is energized. As shown in Figure 26, the magnetic flux density detected by the magnetic sensor 190 changes almost linearly according to the axial position of the selector 170.

[0177] Therefore, the determination circuit unit estimates the axial position of the selector 170 from the magnitude of the magnetic flux density based on the relationship shown in Figure 26. The determination circuit unit compares the estimated position of the selector 170 with the third and fourth threshold values ​​that are set in advance for the axial position of the selector 170.

[0178] For example, if the estimated position of the selector 170 is less than the third threshold, the determination circuit determines that the selector 170 has stopped the rotation of the pole piece shaft 160 and is rotating the outer magnet shaft 150. Also, if the estimated position of the selector 170 is greater than the fourth threshold, the determination circuit determines that the selector 170 has stopped the rotation of the outer magnet shaft 150 and is rotating the pole piece shaft 160. Furthermore, if the estimated position of the selector 170 is between the third and fourth thresholds, the determination circuit determines that an abnormality has occurred in the magnetic gear section 10. In this way, the determination circuit can detect rotation based on the relationship between the magnetic flux of the permanent magnet 176 and the position of the selector 170.

[0179] Note that the threshold setting for the axial position of the selector 170 is just one example. For example, the determination circuit may perform rotation detection based on a single threshold.

[0180] As described above, even when the position of the selector 170 is detected as magnetic flux by the magnetic sensor 190, the same effects as in the first embodiment can be obtained.

[0181] (Sixth Embodiment) This embodiment mainly describes the parts that differ from the above embodiments. As shown in Figure 27, the power transmission device 1 includes a search coil 193. The search coil 193 is installed in a position that is affected by the magnetic field of the permanent magnet 176 of the selector 170. In this embodiment, the search coil 193 is located outside the yoke 172 in the radial direction. As a result, the search coil 193 detects the change in the magnetic field it receives from the permanent magnet 176 as an induced electromotive force as the selector 170 moves.

[0182] Figure 28 shows an example of a method for measuring the induced electromotive force of the search coil 193. For example, the power supply 194A is connected to the coil 171 via a forward / reverse switch 194B. The momentary switch 194C is connected between the power supply 194A and the forward / reverse switch 194B.

[0183] A current probe 194E is connected to channel 1 of the data logger 194D. The current probe 194E probes between the power supply 194A and the momentary switch 194C. In addition, both ends of the search coil 193 are connected to channel 2 of the data logger 194D.

[0184] In the above configuration, for example, the direction of movement of the selector 170 is set by the forward / reverse switch 194B. Also, while the momentary switch 194C is ON, the selector 170 is moved and the induced electromotive force of the search coil 193 is measured by the data logger 194D. The measurement results are shown in Figure 29.

[0185] First, the forward / reverse switch 194B is switched so that the outer magnet shaft 150 rotates. At time T1, the momentary switch 194C is turned on, causing current to flow through the coil 171. This corresponds to the selector control circuit and motor controller receiving a control command to rotate the pole piece shaft 160, and the selector control circuit supplying current in the first current direction (forward direction) to the coil 171. As a result, the selector 170 rises and is displaced from the second selector position towards the first selector position.

[0186] Furthermore, the change in the magnetic field of the permanent magnet 176 due to the displacement of the selector 170 affects the search coil 193, causing the induced electromotive force of the search coil 193 to start rising as a positive voltage from time T1. Therefore, the determination circuit unit uses a threshold value or the like to determine that the induced electromotive force of the search coil 193 has changed to a positive voltage. As a result, the determination circuit unit can determine that the pole piece shaft 160 is rotating.

[0187] The displacement of the selector 170 and the induced electromotive force of the search coil 193 reach their maximum values ​​at time T2. After time T2, the selector 170 stops displacing. In other words, the selector 170 reaches the first selector position. Also, since the change in the magnetic field of the permanent magnet 176 due to the movement of the selector 170 ceases, the induced electromotive force of the search coil 193 returns to 0.

[0188] Next, the forward / reverse switch 194B is switched so that the pole piece shaft 160 rotates. At time T3, the momentary switch 194C is turned on, causing current to flow through the coil 171. This corresponds to the selector control circuit and motor controller receiving a control command to rotate the outer magnet shaft 150, and the selector control circuit also supplying current to the coil 171 in the second current direction (reverse direction). As a result, the selector 170 descends and is displaced from the first selector position towards the second selector position.

[0189] Furthermore, the change in the magnetic field of the permanent magnet 176 due to the displacement of the selector 170 affects the search coil 193, causing the induced electromotive force of the search coil 193 to start rising as a negative voltage from time T3. Therefore, the determination circuit unit uses a threshold value or the like to determine that the induced electromotive force of the search coil 193 has changed to a negative voltage. As a result, the determination circuit unit can determine that the outer magnet shaft 150 is rotating.

[0190] At time T4, similar to time T2, the selector 170 reaches the second selector position, and the induced electromotive force of the search coil 193 reaches its maximum value. After time T4, the selector 170 stops moving. In other words, the selector 170 reaches the second selector position. Also, the change in the magnetic field of the permanent magnet 176 due to the movement of the selector 170 ceases, so the induced electromotive force of the search coil 193 returns to 0.

[0191] As described above, using the search coil 193 improves the accuracy of determining the rotation of the outer magnet shaft 150 and the pole piece shaft 160. Note that the installation position of the search coil 193 is not limited to those shown in Figures 27 and 28. The search coil 193 only needs to be installed in a position that is affected by the magnetic field of the permanent magnet 176 of the selector 170.

[0192] This disclosure is not limited to the embodiments described above, and can be modified in various ways without departing from the spirit of this disclosure, as follows.

[0193] For example, the power transmission device 1 may be configured as a device that operates a valve other than a steam pressure regulating valve or an expansion valve.

[0194] This disclosure is described in accordance with the embodiments, but it is understood that this disclosure is not limited to such embodiments or structures. This disclosure also includes various modifications and variations within the equivalence. In addition, various combinations and forms, as well as other combinations and forms that include only one, more, or fewer of those elements, fall within the scope and concept of this disclosure.

[0195] The technical features of the power transmission device 1 disclosed herein are as follows: (Item 1) An inner magnet shaft (140) having a drive shaft (141A) and a plurality of inner magnetic poles (142A, 142B) provided on the outer circumference of the drive shaft, wherein the plurality of inner magnetic poles rotate integrally with the drive shaft; an outer magnet shaft (150) having a plurality of outer magnetic poles (152A, 152B) which have more poles than the plurality of inner magnetic poles of the inner magnet shaft and are arranged on the outer circumference of the plurality of inner magnetic poles, and which is rotatably supported on the rotation shaft (141B) of the drive shaft; a pole piece shaft (160) having a plurality of magnetic material parts (162) which are located between the plurality of inner magnetic poles and the plurality of outer magnetic poles in a radial direction perpendicular to the rotation shaft and are arranged on the outer circumference of the plurality of inner magnetic poles, which is rotatably supported on the rotation shaft and rotates by modulating the magnetic flux between the plurality of inner magnetic poles and the plurality of outer magnetic poles, A power transmission device comprising: a selector (170) that selectively stops the rotation of either the outer magnet shaft or the pole piece shaft based on a command; and a magnetic sensor (190) positioned to be affected by the magnetic flux of either or both of the plurality of outer magnetic poles and the plurality of magnetic material parts, and which detects the change in magnetic flux density and its magnitude as the outer magnet shaft or the pole piece shaft rotates. (Item 2) The power transmission device according to Item 1, wherein the magnetic sensor has detection units (191, 192) that generate a detection signal based on the change in magnetic flux density and its magnitude received from the outside, and the detection units are positioned outside a rotating body (10A) in which the plurality of inner magnetic poles, the plurality of outer magnetic poles, and the plurality of magnetic material parts are arranged concentrically around the rotation axis, and further positioned in the outer peripheral region (10B) of the outside of the rotating body projected radially, within the range of the rotation axis.(Item 3) The power transmission device according to Item 1 or 2, wherein the magnetic sensor has detection units (191, 192) that generate a detection signal based on the change in magnetic flux density received from the outside and its magnitude, and the detection units are located on the outside of a rotating body (10A) in which a plurality of inner magnetic poles, a plurality of outer magnetic poles, and a plurality of magnetic body parts are arranged concentrically around the rotation axis, and further located in an outer peripheral region (10B) of the outside of the rotating body projected radially, in which the outer magnetic poles protrude from the inner magnetic poles in the axial direction of the rotation axis and the outer magnetic poles and the inner magnetic poles do not overlap radially. (Item 4) The power transmission device according to Item 1 or 2, wherein the magnetic sensor has detection units (191, 192) that generate a detection signal based on the change in magnetic flux density received from the outside and its magnitude, and the detection units are positioned outside a rotating body (10A) in which a plurality of inner magnetic poles, a plurality of outer magnetic poles, and a plurality of magnetic material parts are arranged concentrically around the rotation axis, and further positioned in an axial region (10D) on the outside of the rotating body, projected in the axial direction of the rotation axis, on the circle of the pole piece circle drawn in the axial region by the rotation of the plurality of magnetic material parts, or on the circle of the outer circle drawn in the axial region by the rotation of the plurality of outer magnetic poles, or on the circle of the intermediate circle between the pole piece circle and the outer circle in the axial region.(Item 5) The plurality of outer magnetic poles have a plurality of outer N poles (152A) and a plurality of outer S poles (152B) that generate a magnetic field along the radial direction, and the outer N poles and the outer S poles are arranged alternately in the circumferential direction around the rotation axis, The magnetic sensor has a first detection unit (191) that generates a first detection signal based on the change in magnetic flux density received from the outside and its magnitude, and a second detection unit (192) that generates a second detection signal based on the change in magnetic flux density received from the outside and its magnitude, The first detection unit and the second detection unit are arranged on the outside of a rotating body (10A) in which the plurality of inner magnetic poles, the plurality of outer magnetic poles and the plurality of magnetic material parts are arranged concentrically around the rotation axis, and the first detection unit corresponds to the outer N pole and the second detection unit corresponds to the outer S pole, The power transmission device according to any one of items 1 to 4, wherein the first detection signal and the second detection signal are used to determine the rotation of the outer magnet shaft and the pole piece shaft by performing calculations. (Item 6) The power transmission device according to item 5, wherein the first detection unit and the second detection unit are arranged along the circumference so as to be adjacent to each other, corresponding to the pitch of one magnetic pole between adjacent outer N poles and outer S poles. (Item 7) The power transmission device according to item 5 or 6, wherein the first detection signal and the second detection signal are used to determine the rotation of the outer magnet shaft and the pole piece shaft by performing either addition or subtraction or both. (Item 8) A power transmission device according to any one of items 1 to 7, comprising: a first valve body (220) connected to the pole piece shaft and whose valve opening degree changes with rotation of the pole piece shaft; a second valve body (240) connected to the outer magnet shaft and whose valve opening degree changes with rotation of the outer magnet shaft; a first valve chamber (210) housing the first valve body; and a second valve chamber (230) housing the second valve body.(Item 9) An inner magnet shaft (140) having a drive shaft (141A) and a plurality of inner magnetic poles (142A, 142B) provided on the outer circumference of the drive shaft, wherein the plurality of inner magnetic poles rotate integrally with the drive shaft; an outer magnet shaft (150) having a plurality of outer magnetic poles (152A, 152B) which have more poles than the plurality of inner magnetic poles of the inner magnet shaft and are arranged on the outer circumference of the plurality of inner magnetic poles, and which is rotatably supported on the rotation shaft (141B) of the drive shaft; a pole piece shaft (160) having a plurality of magnetic material parts (162) which are located between the plurality of inner magnetic poles and the plurality of outer magnetic poles in a radial direction perpendicular to the rotation shaft and are arranged on the outer circumference of the plurality of inner magnetic poles, which is rotatably supported on the rotation shaft and rotates by modulating the magnetic flux between the plurality of inner magnetic poles and the plurality of outer magnetic poles, A power transmission device comprising: a selector (170) configured to include a selector magnetic material, which selectively stops the rotation of either the outer magnet shaft or the pole piece shaft by moving its position relative to the outer magnet shaft and the pole piece shaft based on a command; and a magnetic sensor (190) positioned in a location affected by the magnetic flux from the selector magnetic material of the selector, and which detects the magnitude of the magnetic flux density corresponding to the position of the selector relative to the outer magnet shaft and the pole piece shaft. (Item 10) The power transmission device according to Item 9, comprising an inner magnet shaft, an outer magnet shaft, a pole piece shaft, and a housing (130) housing the selector, wherein the selector has a permanent magnet (176) as the selector magnetic material, and has a holding function that moves to a first selector position relative to the housing and holds the first selector position when the rotation of the outer magnet shaft is stopped, and moves to a second selector position relative to the housing and holds the second selector position when the rotation of the pole piece shaft is stopped, and the magnetic sensor detects the magnitude of the magnetic flux density received from the permanent magnet at the first selector position or the second selector position of the selector.(Item 11) A power transmission device according to item 9 or 10, comprising: a housing (130) housing the inner magnet shaft, the outer magnet shaft, the pole piece shaft, and the selector; a yoke (172) provided in the housing, wherein the selector has a permanent magnet (176) as the selector magnetic material, moves to a first selector position relative to the housing when the rotation of the outer magnet shaft is stopped and forms a first magnetic circuit (178A) between the yoke and the permanent magnet at the first selector position, while moves to a second selector position relative to the housing when the rotation of the pole piece shaft is stopped and forms a second magnetic circuit (178B) between the yoke and the permanent magnet at the second selector position, the first magnetic flux direction of the magnetic flux in the first magnetic circuit and the second magnetic flux direction of the magnetic flux in the second magnetic circuit are in opposite directions, and the magnetic sensor detects the first magnetic flux direction or the second magnetic flux direction of the magnetic flux generated in the first magnetic circuit or the second magnetic circuit. (Item 12) A power transmission device according to any one of items 9 to 11, comprising: a housing (130) housing the inner magnet shaft, the outer magnet shaft, the pole piece shaft, and the selector; a coil (171) provided in the housing; and a yoke (172) surrounding the coil and forming a magnetic path inside when the coil is energized, wherein the selector moves to a first selector position relative to the housing by energizing the coil in a first current direction when the rotation of the outer magnet shaft is stopped, and moves to a second selector position relative to the housing by energizing the coil in a second current direction opposite to the first current direction when the rotation of the pole piece shaft is stopped, and the magnetic sensor is embedded in the yoke and detects the direction of the magnetic flux generated inside the yoke in the first current direction or the second current direction.(Item 13) The power transmission device according to any one of items 9 to 12, wherein the selector has a permanent magnet (176) as the magnetic material for the selector, moves to a first selector position when stopping the rotation of the outer magnet shaft and holds the first selector position by the magnetic force of the permanent magnet, and moves to a second selector position when stopping the rotation of the pole piece shaft and holds the second selector position by the magnetic force of the permanent magnet, and includes a search coil (193) installed in a position affected by the magnetic field of the permanent magnet of the selector, which detects the change in the magnetic field received from the permanent magnet as the selector moves as an induced electromotive force. (Item 14) A power transmission device according to any one of items 9 to 13, comprising: a first valve body (220) connected to the pole piece shaft and whose valve opening degree changes with rotation of the pole piece shaft; a second valve body (240) connected to the outer magnet shaft and whose valve opening degree changes with rotation of the outer magnet shaft; a first valve chamber (210) housing the first valve body; and a second valve chamber (230) housing the second valve body.

Claims

1. An inner magnet shaft (140) having a drive shaft (141A) and a plurality of inner magnetic poles (142A, 142B) provided on the outer circumference of the drive shaft, wherein the plurality of inner magnetic poles rotate integrally with the drive shaft; an outer magnet shaft (150) having a plurality of outer magnetic poles (152A, 152B) which have more poles than the plurality of inner magnetic poles of the inner magnet shaft and are arranged on the outer circumference of the plurality of inner magnetic poles, and which is rotatably supported on the rotation axis (141B) of the drive shaft; a pole piece shaft (160) having a plurality of magnetic material parts (162) which are located between the plurality of inner magnetic poles and the plurality of outer magnetic poles in a radial direction perpendicular to the rotation axis and are arranged on the outer circumference of the plurality of inner magnetic poles, which is rotatably supported on the rotation axis and rotates by modulating the magnetic flux between the plurality of inner magnetic poles and the plurality of outer magnetic poles; A power transmission device comprising: a selector (170) that selectively stops the rotation of either the outer magnet shaft or the pole piece shaft based on a command; and a magnetic sensor (190) positioned to be affected by the magnetic flux of one or both of the multiple outer magnetic poles and multiple magnetic body parts, and which detects the change in magnetic flux density and its magnitude as the outer magnet shaft or the pole piece shaft rotates.

2. The power transmission device according to claim 1, wherein the magnetic sensor has detection units (191, 192) that generate a detection signal based on the change in magnetic flux density received from the outside and its magnitude, and the detection units are located on the outside of a rotating body (10A) in which a plurality of inner magnetic poles, a plurality of outer magnetic poles, and a plurality of magnetic body parts are arranged concentrically around the rotation axis, and further located in the outer peripheral region (10B) of the outside of the rotating body, projected radially onto the rotating body, and within the axial range of the rotation axis.

3. The power transmission device according to claim 1 or 2, wherein the magnetic sensor has detection units (191, 192) that generate a detection signal based on the change in magnetic flux density received from the outside and its magnitude, and the detection units are located on the outside of a rotating body (10A) in which a plurality of inner magnetic poles, a plurality of outer magnetic poles, and a plurality of magnetic body parts are arranged concentrically around the rotation axis, and further located in an outer peripheral region (10B) of the outside of the rotating body projected radially, in an axial overhang region (10C) in which the outer magnetic poles protrude from the inner magnetic poles in the axial direction of the rotation axis and the outer magnetic poles and the inner magnetic poles do not overlap radially.

4. The power transmission device according to claim 1 or 2, wherein the magnetic sensor has detection units (191, 192) that generate a detection signal based on the change in magnetic flux density received from the outside and its magnitude, and the detection units are positioned outside a rotating body (10A) in which a plurality of inner magnetic poles, a plurality of outer magnetic poles, and a plurality of magnetic material parts are arranged concentrically around the rotation axis, and further positioned in an axial region (10D) outside the rotating body, obtained by projecting the rotating body in the axial direction of the rotation axis, on the circle of the pole piece circle drawn in the axial region by the rotation of the plurality of magnetic material parts, or on the circle of the outer circle drawn in the axial region by the rotation of the plurality of outer magnetic poles, or on the circle of the intermediate circle between the pole piece circle and the outer circle in the axial region.

5. The plurality of outer magnetic poles have a plurality of outer N poles (152A) and a plurality of outer S poles (152B) that generate a magnetic field along the radial direction, and the outer N poles and outer S poles are alternately arranged in the circumferential direction around the rotation axis, and the magnetic sensor has a first detection unit (191) that generates a first detection signal based on the change in magnetic flux density received from the outside and its magnitude, and a second detection unit (192) that generates a second detection signal based on the change in magnetic flux density received from the outside and its magnitude, and the first detection unit and the second detection unit are arranged on the outside of a rotating body (10A) in which the plurality of inner magnetic poles, the plurality of outer magnetic poles and the plurality of magnetic material parts are arranged concentrically around the rotation axis, and the first detection unit corresponds to the outer N pole and the second detection unit corresponds to the outer S pole, The power transmission device according to claim 1, wherein the first detection signal and the second detection signal are used to determine the rotation of the outer magnet shaft and the pole piece shaft by calculation.

6. The power transmission device according to claim 5, wherein the first detection unit and the second detection unit are arranged along the circumferential direction so as to be adjacent to each other, corresponding to a pitch of one magnetic pole between adjacent outer N poles and outer S poles.

7. The power transmission device according to claim 5 or 6, wherein the first detection signal and the second detection signal are used to determine the rotation of the outer magnet shaft and the pole piece shaft by performing either addition or subtraction or both.

8. A power transmission device according to claim 1 or 2, comprising: a first valve body (220) connected to the pole piece shaft, the valve opening degree of which changes with rotation of the pole piece shaft; a second valve body (240) connected to the outer magnet shaft, the valve opening degree of which changes with rotation of the outer magnet shaft; a first valve chamber (210) housing the first valve body; and a second valve chamber (230) housing the second valve body.

9. An inner magnet shaft (140) having a drive shaft (141A) and a plurality of inner magnetic poles (142A, 142B) provided on the outer circumference of the drive shaft, wherein the plurality of inner magnetic poles rotate integrally with the drive shaft; an outer magnet shaft (150) having a plurality of outer magnetic poles (152A, 152B) which have more poles than the plurality of inner magnetic poles of the inner magnet shaft and are arranged on the outer circumference of the plurality of inner magnetic poles, and which is rotatably supported on the rotation shaft (141B) of the drive shaft; a pole piece shaft (160) having a plurality of magnetic material parts (162) which are located between the plurality of inner magnetic poles and the plurality of outer magnetic poles in a radial direction perpendicular to the rotation shaft and are arranged on the outer circumference of the plurality of inner magnetic poles, which is rotatably supported on the rotation shaft and rotates by modulating the magnetic flux between the plurality of inner magnetic poles and the plurality of outer magnetic poles; A power transmission device comprising: a selector (170) configured to include a selector magnetic material, which selectively stops the rotation of either the outer magnet shaft or the pole piece shaft by moving its position relative to the outer magnet shaft and the pole piece shaft based on a command; and a magnetic sensor (190) positioned in a location affected by the magnetic flux from the selector magnetic material of the selector, and which detects the magnitude of the magnetic flux density corresponding to the position of the selector relative to the outer magnet shaft and the pole piece shaft.

10. The power transmission device according to claim 9, comprising an inner magnet shaft, an outer magnet shaft, a pole piece shaft, and a housing (130) housing the selector, wherein the selector has a permanent magnet (176) as the selector magnetic material, and has a holding function that moves to a first selector position relative to the housing and holds the first selector position when the rotation of the outer magnet shaft is stopped, and moves to a second selector position relative to the housing and holds the second selector position when the rotation of the pole piece shaft is stopped, and the magnetic sensor detects the magnitude of the magnetic flux density received from the permanent magnet at the first selector position or the second selector position of the selector.

11. A power transmission device according to claim 9 or 10, comprising: a housing (130) housing the inner magnet shaft, the outer magnet shaft, the pole piece shaft, and the selector; a yoke (172) provided in the housing, wherein the selector has a permanent magnet (176) as the selector magnetic material, moves to a first selector position relative to the housing when the rotation of the outer magnet shaft is stopped and forms a first magnetic circuit (178A) between the yoke and the permanent magnet at the first selector position, while moves to a second selector position relative to the housing when the rotation of the pole piece shaft is stopped and forms a second magnetic circuit (178B) between the yoke and the permanent magnet at the second selector position, the first magnetic flux direction of the magnetic flux in the first magnetic circuit and the second magnetic flux direction of the magnetic flux in the second magnetic circuit are in opposite directions, and the magnetic sensor detects the first magnetic flux direction or the second magnetic flux direction of the magnetic flux generated in the first magnetic circuit or the second magnetic circuit.

12. A power transmission device according to claim 9 or 10, comprising: a housing (130) housing the inner magnet shaft, the outer magnet shaft, the pole piece shaft, and the selector; a coil (171) provided in the housing; and a yoke (172) surrounding the coil and forming a magnetic path inside when the coil is energized, wherein the selector moves to a first selector position relative to the housing by energizing the coil in a first current direction when stopping the rotation of the outer magnet shaft, and moves to a second selector position relative to the housing by energizing the coil in a second current direction opposite to the first current direction when stopping the rotation of the pole piece shaft; and a magnetic sensor embedded in the yoke, which detects the direction of the magnetic flux generated inside the yoke in the first current direction or the second current direction.

13. The power transmission device according to claim 9 or 10, wherein the selector has a permanent magnet (176) as the magnetic material for the selector, moves to a first selector position when stopping the rotation of the outer magnet shaft and holds the first selector position by the magnetic force of the permanent magnet, and moves to a second selector position when stopping the rotation of the pole piece shaft and holds the second selector position by the magnetic force of the permanent magnet, and includes a search coil (193) installed in a position affected by the magnetic field of the permanent magnet of the selector, which detects the change in the magnetic field received from the permanent magnet as the selector moves as an induced electromotive force.

14. A power transmission device according to claim 9 or 10, comprising: a first valve body (220) connected to the pole piece shaft, the valve opening degree of which changes with rotation of the pole piece shaft; a second valve body (240) connected to the outer magnet shaft, the valve opening degree of which changes with rotation of the outer magnet shaft; a first valve chamber (210) housing the first valve body; and a second valve chamber (230) housing the second valve body.

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