Coreless motor

Abstract

A coreless motor is provided with: an integrated shaft extending through the center of the coreless motor; a cylindrical coil which is disposed concentrically with the shaft, one end surface of which is supported by the stator, extends in the direction in which the shaft extends, and is stationary; a rotor which is disposed concentrically with the shaft, is composed of a cylindrical inner yoke and a cylindrical outer yoke which sandwich the cylindrical coil between each other and which form a magnetic circuit by having a magnet on the facing surfaces of the inner yoke and the outer yoke, and is rotatably supported by the shaft; a housing having a rotatable cylindrical portion disposed concentrically with the shaft on the outside of the outer yoke; a rotational motion transmission mechanism that outputs the rotational motion of the rotor to the cylindrical housing on the inside of the cylindrical coil so as to transmit and output the rotational motion to the outside of the coreless motor; the rotational motion transmission mechanism is configured from a gear mechanism provided with a plurality of gear members inside a cylindrical coil, in which a high-speed-side sun gear is rotatably supported by a shaft through which a shaft passes, and the shaft passes through a cylindrical housing and supports the cylindrical housing.

Description

[0001] This application is a divisional application of a patent application for an ironless motor, with an application date of December 21, 2018, an application number of 201880068785.2, and an invention title of "Ironless Motor". Technical Field

[0002] The present invention relates to an ironless motor. In particular, it relates to an ironless motor in which a rotational motion transmission mechanism is built into the ironless motor, and the rotational motion transmission mechanism is used to output the rotational motion of a rotating part (rotor) inside the ironless motor to the outside of the ironless motor. Background Art

[0003] Conventionally, a scheme has been proposed to install units such as a speed reducer or a brake on one side of the rotating shaft of the motor where the object to be driven is installed, that is, the output side of the rotating shaft, or the opposite side thereof.

[0004] For example, Patent Document 2 proposes a motor in which a planetary roller mechanism is arranged between a power shaft and a rotor arranged concentrically with the power shaft.

[0005] In addition, Patent Document 1 describes a motor with a speed reducer. This motor with a speed reducer is an iron-core type motor, and units such as a speed reducer are built into the motor. An armature is arranged around a fixed shaft and a cylindrical rotor surrounds them. Around the rotor, a cylindrical outer roller that can rotate relative to the fixed shaft is arranged. A rotational motion transmission mechanism is arranged between the inner side of the outer roller and the end of the rotor and the outer roller, and this rotational motion transmission mechanism transmits the rotational motion of the rotor centered on the fixed shaft to the outer roller. The rotational motion transmission mechanism includes a plurality of central gears and planetary gears whose centers are penetrated by the fixed shaft.

[0006] Patent Documents 1 and 2 are so-called iron-core type motors. In such iron-core type motors, a scheme has been conventionally proposed to build units such as a speed reducer into the interior of the motor.

[0007] On the other hand, in an ironless type motor, that is, an ironless motor, a scheme of building units such as a speed reducer into the interior has not been proposed conventionally.

[0008] This is because in the case of an ironless motor, it is usually a miniaturized motor, so it is extremely difficult to build units such as a speed reducer into the interior of the motor.

[0009] Patent Document 3 is an invention regarding a coreless motor proposed by the inventor of the present invention application. The central axis that becomes the center of rotation extends in the center in the radial direction, and a cylindrical coil extending in the direction along the central axis is arranged concentrically with respect to the central axis. The rotor includes a cylindrical inner yoke and a cylindrical outer yoke that sandwich the coil between them in the radial direction and are arranged concentrically with respect to the aforementioned central axis.

[0010] The coreless motor described in Patent Document 3 has a structure in which the central axis that becomes the center of rotation penetrates inside the coreless motor. That is, the central axis penetrates the cylindrical coil in the direction in which the cylindrical coil extends. In addition, the central axis penetrates the rotor having an inner yoke and an outer yoke.

[0011] Since the coreless motor with such a structure is a miniaturized motor as described above, it is considered that it is fundamentally difficult to incorporate units such as a speed reducer. Even the coreless motor described in Patent Document 3 does not incorporate units such as a speed reducer.

[0012] Patent Document 4 is a document regarding a hub motor proposed by the inventor of the present invention application. The coreless motor described in Patent Document 4 has the following structure.

[0013] A shaft that extends axially in the center of the coreless motor and penetrates the coreless motor. A cylindrical coil that is arranged concentrically with respect to the shaft, with one end face supported by a coil support, and extends in the direction along the shaft. A rotor that is arranged concentrically with respect to the shaft, is composed of a cylindrical inner yoke and an outer yoke, and is rotatably supported by the shaft on the center side in the radial direction. The inner yoke and the outer yoke sandwich the cylindrical coil between them in the radial direction, and have magnets on the surfaces of either one facing the other to form a magnetic circuit between them. A hub that is fixedly attached to the outer yoke and holds a tire. If the outer yoke rotates around the shaft, the hub fixed to the outer yoke holds the tire and rotates around the shaft.

[0014] Even the coreless motor described in Patent Document 4 does not incorporate units such as a speed reducer.

[0015] Thus, in a coreless type motor, that is, a coreless motor, as in Patent Documents 3 and 4, a scheme of incorporating units such as a speed reducer inside has not been proposed in the past.

[0016] Prior Art Documents

[0017] Patent Documents

[0018] Patent Document 1: Japanese Utility Model Laid-Open No. 50-148792

[0019] Patent Document 2: Japanese Patent Laid-Open No. 2003-143805

[0020] Patent Document 3: WO2015 / 162826

[0021] Patent Document 4: Japanese Patent Application Publication No. 2017-186006 Summary of the invention

[0022] Technical problem to be solved by the invention

[0023] Patent Document 4, which describes a hub motor composed of an ironless coreless motor, does not describe "a cylindrical housing having a cylindrical portion arranged concentrically with respect to the shaft on the outer side of the outer yoke in the radial direction, the cylindrical portion rotating around the shaft". In addition, Patent Document 4 does not describe "a rotational motion transmission mechanism disposed inside the cylindrical housing to transmit the rotational motion of the rotor around the shaft to the cylindrical housing".

[0024] The invention described in Patent Document 4 is an invention for the purpose of "facilitating the assembly of the wheel hub motor". It is an invention based on the premise that the wheel hub supporting the tire is fixed to the rotor (outer yoke) and the wheel hub supporting the tire rotates with the rotation of the rotor (outer yoke) around the axis (fixed axis). Therefore, Patent Document 4 does not contain the opportunity or cause to think of interposing a speed reducer structure between the rotor (outer yoke) and the wheel hub supporting the tire to reduce the rotation of the wheel hub supporting the tire.

[0025] Thus, there has been no opportunity or reason to apply the mechanism of a motor having a reducer and other units built into an iron-core type motor as described in Patent Document 1 to an iron-coreless motor as described in Patent Document 4.

[0026] The object of the present invention is to provide a coreless motor in which a rotational motion transmission mechanism is built into the coreless motor, and the rotational motion transmission mechanism is used to output the rotational motion of the rotating part (rotor) inside the coreless motor to the outside of the coreless motor.

[0027] Means for solving technical problems

[0028] [1] An ironless motor comprising:

[0029] A fixed shaft extending axially at the center of the ironless core motor and penetrating the ironless core motor;

[0030] a cylindrical coil arranged concentrically with respect to the fixed axis, one end surface of which is supported by the stator, and extending in the direction in which the fixed axis extends;

[0031] A rotor, which is arranged concentrically with respect to the fixed shaft, is composed of a cylindrical inner yoke and a cylindrical outer yoke, and is rotatably supported by the fixed shaft on the center side in the radial direction. The inner yoke and the outer yoke sandwich the cylindrical coil between them in the radial direction, and have magnets on the surfaces of either side facing the other side to form a magnetic circuit between them;

[0032] A cylindrical housing, which has a cylindrical portion arranged concentrically with respect to the fixed shaft on the outside of the outer yoke in the radial direction, and this cylindrical portion rotates around the fixed shaft; and

[0033] A rotational motion transmission mechanism, which is provided inside the cylindrical housing and transmits the rotational motion of the rotor around the fixed shaft to the cylindrical housing.

[0034] [2] The coreless motor according to [1], wherein the rotational motion transmission mechanism is composed of a gear mechanism having a plurality of gear components, and the fixed shaft penetrates through the gear component located on one side of the fixed shaft in the radial direction and rotatably supports this gear component in the gear mechanism.

[0035] [3] A coreless motor, comprising:

[0036] A shaft, which is an integral shaft extending through the coreless motor in the center of the coreless motor;

[0037] A cylindrical coil, which is arranged concentrically with respect to the shaft, has one end face supported by the stator, and extends along the extending direction of the shaft and is stationary;

[0038] A rotor, which is arranged concentrically with respect to the shaft, is composed of a cylindrical inner yoke and an outer yoke, and is rotatably supported by the shaft on the center side in the radial direction. The cylindrical inner yoke and the outer yoke sandwich the cylindrical coil between them in the radial direction, and have magnets on the surfaces of either side facing the other side to form a magnetic circuit between them;

[0039] A cylindrical housing, which has a cylindrical portion arranged concentrically with respect to the fixed shaft on the outside of the outer yoke in the radial direction, and this cylindrical portion rotates around the fixed shaft; and

[0040] A rotational motion transmission mechanism, which is provided inside the cylindrical housing on the inner side in the radial direction of the cylindrical coil, and outputs the rotational motion of the rotor around the shaft to the cylindrical housing at a position radially inside the cylindrical coil to transmit and output it to the outside of the coreless motor;

[0041] The rotational motion transmission mechanism is constituted by a gear mechanism having a plurality of gear members at a position radially inside the cylindrical coil. The high-speed side sun gear in the gear mechanism is penetrated by the shaft and rotatably supported by the shaft.

[0042] The shaft penetrates the cylindrical housing and supports the cylindrical housing.

[0043] Advantages of the Invention

[0044] According to the present invention, there can be provided a coreless motor in which a rotational motion transmission mechanism is built in, and the rotational motion transmission mechanism is configured to output the rotational motion of a rotating part (rotor) inside the coreless motor to the outside of the coreless motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 is a partially cutaway sectional view illustrating the internal structure of an embodiment of the present invention.

[0046] Figure 2 is for explaining Figure 1 a schematic view showing the arrangement form of the sun gear, planet gears, and planet carrier of the rotational transmission part in the illustrated embodiment, (a) is Figure 1 a schematic view of a sectional view taken along line A-A of Figure 1 and (b) is a schematic view of a sectional view taken along line B-B of

[0047] Figure 3 is a partially cutaway sectional view illustrating the internal structure of another embodiment of the present invention.

[0048] Figure 4 is a partially cutaway sectional view illustrating the internal structure of another embodiment of the present invention.

[0049] Figure 5 is a partially cutaway sectional view illustrating the internal structure of another embodiment of the present invention.

[0050] Figure 6 is a partially cutaway sectional view illustrating the internal structure of another embodiment of the present invention.

[0051] Figure 7 is a partially cutaway sectional view illustrating the internal structure of another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0052] <Embodiment 1>

[0053] Figure 1An example of an embodiment of a rotational motion transmission mechanism is shown that is built into a coreless motor to output the rotational motion of a rotating part (rotor) inside the coreless motor to the outside of the coreless motor.

[0054] The coreless motor 1 shown in Fig. 1 includes a fixed shaft 2, a stator 3, a cylindrical coil 4, a rotor 8, a cylindrical housing 10, and a rotational motion transmission mechanism.

[0055] The fixed shaft 2 extends axially in the center of the coreless motor 1 and penetrates the coreless motor 1.

[0056] The cylindrical coil 4 is arranged concentrically with respect to the fixed shaft 2, one end face is supported by the stator 3, and it extends in the direction in which the fixed shaft 2 extends. The inner side in the radial direction of the stator 3 is fixed to the fixed shaft 2.

[0057] The cylindrical coil 4 is a coreless coil that can be energized. In the illustrated embodiment, in Fig. 1, a laminated body structure of conductive metal sheets formed by overlapping a plurality of linear parts separated from the length direction, that is, the direction in which the fixed shaft 2 extends, via an insulating layer is formed into a cylindrical shape. The thickness in the radial direction is, for example, 5 mm or less, and it has a specified rigidity. Such a cylindrical coil can be manufactured, for example, by the manufacturing method described in Japanese Patent No. 3704044.

[0058] The rotor 8 includes a cylindrical inner yoke 6, a cylindrical outer yoke 5, and a magnet 7. The cylindrical inner yoke 6 and the cylindrical outer yoke 5 are arranged concentrically with respect to the fixed shaft 2, and the cylindrical coil 4 is sandwiched between them in the radial direction.

[0059] The magnet 7 made of a permanent magnet or the like is provided on the surface of either the inner yoke 6 or the outer yoke 5 on the side facing the other. In the illustrated embodiment, the magnet 7 is provided on the inner peripheral surface of the outer yoke 5 facing the outer peripheral surface of the inner yoke 6. In this way, a magnetic field with an annular cross-section is formed between the outer yoke 5 and the inner yoke 6, forming a magnetic circuit.

[0060] Instead of the illustrated embodiment, a structure in which the magnet 7 is provided on the outer peripheral surface of the inner yoke 6 can also be adopted.

[0061] The rotor 8 is rotatably supported by the fixed shaft 2 on the center side in the radial direction. In the illustrated embodiment, the rotor 8 has a cylindrical part on the center side in the radial direction, the fixed shaft 2 penetrates inside the cylindrical part, and the fixed shaft 2 rotatably supports the cylindrical part. Thus, the rotor 8 is configured to be rotatably supported by the fixed shaft 2.

[0062] The cylindrical housing 10 has a cylindrical part 9 arranged concentrically with respect to the fixed shaft 2 on the outside of the outer yoke 5 in the radial direction.

[0063] At both ends of the cylindrical portion 9 in the direction extending from the fixed shaft 2, housing support portions extend in the radial direction toward the fixed shaft 2. The inner side in the radial direction of each housing support portion is configured to be rotatably supported on the fixed shaft 2 via a bearing or the like. Thus, the cylindrical housing 10 and its cylindrical portion 9 can rotate about the fixed shaft 2 as the center.

[0064] A rotational motion transmission mechanism is provided inside the cylindrical housing 10 to transmit the rotational motion of the rotor 8 about the fixed shaft 2 to the rotational motion of the cylindrical housing 10 about the fixed shaft 2. Thus, the cylindrical housing 10 rotates about the fixed shaft 2 as the center.

[0065] As described above, when a magnetic field with an annular cross-section is formed between the inner yoke 6 and the outer yoke 5, by supplying a specified current to the cylindrical coil 4, the rotor 8 rotates about the fixed shaft 2 as the center.

[0066] The rotational motion of the rotor 8 about the fixed shaft 2 is transmitted to the cylindrical portion 9 of the cylindrical housing 10 via the rotational motion transmission mechanism, and the cylindrical housing 10 and its cylindrical portion 9 rotate about the fixed shaft 2 corresponding to the rotational motion of the rotor 8 about the fixed shaft 2.

[0067] The rotational motion transmission mechanism can be constituted by a gear mechanism having a plurality of gear components. For example, a speed reducer constituted by a gear mechanism having a plurality of gear components can be adopted. In the embodiment illustrated in Fig. 1, it is a two-stage reduction mechanism that transmits the rotational motion of the rotor 8 about the fixed shaft 2 to the rotational motion of the cylindrical housing 10 and its cylindrical portion 9 about the fixed shaft 2. As this two-stage reduction mechanism, a planetary gear mechanism having a plurality of gear components is adopted.

[0068] By causing the rotation of the rotor 8 to be transmitted to the cylindrical portion 9 of the cylindrical housing 10 via the reduction mechanism, the cylindrical housing 10 and its cylindrical portion 9 rotate circumferentially about the fixed shaft 2.

[0069] Figure 2 Indicates the constitution of Figure 1 An example of the arrangement form of the sun gear, planetary gear, and planet carrier of the rotational motion transmission mechanism constituted by the planetary gear mechanism in the illustrated embodiment. Note that in Figure 2 the inner gear and the like formed on the inner peripheral surface of the cylindrical portion 9 of the cylindrical housing 10 are omitted from the illustration, and the arrangement and combination forms of the sun gear, planetary gear, planet carrier, idler gear, etc. are schematically illustrated.

[0070] In the embodiment illustrated in FIG. 1, the outer periphery of the radially inner portion of the rotor 8 rotatably supported by the fixed shaft 2 becomes the high-speed side sun gear 11. The rotation of the high-speed side sun gear 11 is transmitted to the low-speed side input shaft 14 via the high-speed side planet gear 12 and the high-speed side planet carrier 13. The Figure 1 left end side outer periphery in the low-speed side input shaft 14 becomes the low-speed side sun gear 15. The rotation of the low-speed side sun gear 15 is transmitted to the cylindrical portion 9 of the cylindrical housing 10 via the low-speed side planet carrier 17 and the idler gear (or low-speed side planet gear) 16.

[0071] That is, the rotation is transmitted from the high-speed side sun gear 11 formed on the outer periphery of the radially inner portion of the rotor 8 rotatably supported by the fixed shaft 2 to the high-speed side planet gear 12 and the high-speed side planet carrier 13, and then to the low-speed side input shaft 14 rotatably supported by the fixed shaft 2, the low-speed side sun gear 15 formed on the left end side outer periphery of the low-speed side input shaft 14, and then via the low-speed side planet carrier 17 and the idler gear (or low-speed side planet gear) 16 to the cylindrical portion 9 of the cylindrical housing 10.

[0072] In Figure 1 the illustrated embodiment, the high-speed side sun gear 11 is formed on the outer periphery of the radially inner portion of the rotor 8. That is, on the outer periphery of the cylindrical portion that exists on the radially inner side of the rotor 8 and is rotatably supported by the fixed shaft 2, the high-speed side sun gear 11 is formed. In this way, the fixed shaft 2 has a structure that penetrates the high-speed side sun gear 11 and rotatably supports the high-speed side sun gear 11.

[0073] In addition, in the embodiment illustrated in FIG. 1, the low-speed side input shaft 14 that receives the rotation of the high-speed side sun gear 11 via the high-speed side planet gear 12 and the high-speed side planet carrier 13 is a cylindrical body, and the fixed shaft 2 penetrates through the cylindrical body, and the fixed shaft 2 rotatably supports the cylindrical body.

[0074] And the low-speed side sun gear 15 is formed on the left end side outer periphery of the low-speed side input shaft 14 in FIG. 1. That is, on the Figure 1 left end side outer periphery in the cylindrical body that constitutes the low-speed side input shaft 14 and is rotatably supported by the fixed shaft 2, the low-speed side sun gear 15 is formed.

[0075] In this way, the fixed shaft 2 also has a structure that penetrates the low-speed side sun gear 15 and rotatably supports the low-speed side sun gear 15.

[0076] That is, in Figure 1 the illustrated embodiment, the rotational motion transmission mechanism has the following structure: It is constituted by a gear mechanism including a plurality of gear components, and the fixed shaft 2 penetrates through the gear component located on one side of the fixed shaft 2 in the radial direction in the gear mechanism and rotatably supports the gear component.

[0077] In the embodiment of FIG. 1, the rotational motion transmission mechanism is composed of a gear mechanism including a plurality of gear components, and this rotational motion transmission mechanism is a planetary gear mechanism. Also, as described above, the sun gears on the high-speed side and the low-speed side in this planetary gear mechanism are both penetrated by the fixed shaft 2 and rotatably supported by the fixed shaft 2.

[0078] Thus, the fixed shaft 2 penetrates the gear components of the rotational motion transmission mechanism composed of a gear mechanism including a plurality of gear components and that are located on the fixed shaft 2 side in the radial direction, and rotatably supports this gear component.

[0079] As a result, when the rotational motion of the rotor 8 about the fixed shaft 2 is transmitted to the cylindrical portion 9 of the cylindrical housing 10 via the rotational motion transmission mechanism, and the cylindrical housing 10 and its cylindrical portion 9 rotate about the fixed shaft 2 corresponding to the rotational motion of the rotor 8 about the fixed shaft 2, there is no need to worry about wobbling, vibration, or deviation.

[0080] In Figure 1 the illustrated embodiment, a two-stage reduction mechanism is used to transmit the rotational motion of the rotor 8 about the fixed shaft 2 to the rotational motion of the cylindrical housing 10 and its cylindrical portion 9 about the fixed shaft 2.

[0081] Instead, the rotational motion of the rotor 8 about the fixed shaft 2 can also be transmitted to the rotational motion of the cylindrical housing 10 and its cylindrical portion 9 about the fixed shaft 2 by a single-stage reduction.

[0082] In the case of transmitting the rotational motion of the rotor 8 about the fixed shaft 2 to the rotational motion of the cylindrical housing 10 and its cylindrical portion 9 about the fixed shaft 2 by a single-stage reduction, it is also possible to adopt a configuration in which the rotational motion transmission mechanism is composed of a gear mechanism including a plurality of gear components (such as a planetary gear mechanism), and the fixed shaft 2 penetrates and rotatably supports a gear (such as the sun gear in a planetary gear mechanism) that is located on the fixed shaft 2 side in the radial direction.

[0083] Thereby, when the rotational motion of the rotor 8 about the fixed shaft 2 is transmitted to the cylindrical portion 9 of the cylindrical housing 10 via the rotational motion transmission mechanism, and the cylindrical housing 10 and its cylindrical portion 9 rotate about the fixed shaft 2 corresponding to the rotational motion of the rotor 8 about the fixed shaft 2, there is no need to worry about wobbling, vibration, or deviation.

[0084] As described above, in this embodiment, a gear mechanism having a plurality of gear components such as a planetary gear mechanism is used as a rotational motion transmission mechanism. A fixed shaft penetrates the coreless motor along the axial direction, which is the rotation center of the coreless motor. The housing includes a cylindrical portion that is arranged concentrically with the fixed shaft in the radial direction outside the rotor. The rotational motion transmission mechanism transmits the rotational motion of the rotor of the coreless motor rotating around the fixed shaft to the cylindrical portion of the housing.

[0085] Moreover, a structure is adopted in which the fixed shaft 2 penetrates and rotatably supports a gear on the fixed shaft 2 side in the radial direction in the gear mechanism. For example, a structure is adopted in which the fixed shaft penetrates and rotatably supports a sun gear on the fixed shaft 2 side in the planetary gear mechanism.

[0086] Thus, the rotational motion transmission mechanism can be built into the coreless motor without increasing the size of the miniaturized coreless motor, and the rotational motion of the rotor of the coreless motor around the fixed shaft can be transmitted to the cylindrical portion arranged concentrically with the fixed shaft outside the rotor. In addition, at this time, since the fixed shaft of the coreless motor penetrates a gear on the fixed shaft 2 side in the gear mechanism having a plurality of gear components and rotatably supports the gear, the occurrence of shaking, vibration, and deviation can be suppressed.

[0087] <Embodiment 2>

[0088] Figure 3 The illustrated coreless motor 21 has a fixed shaft 2 of the coreless motor 1 illustrated in FIG. 1 composed of rod-shaped shaft bodies 2a, 2b, and 2c that are divided into three parts along the axial extension direction.

[0089] In other aspects, it is the same as the coreless motor 1 illustrated in FIG. 1. Therefore, for the common parts, the same reference numerals are given and their descriptions are omitted.

[0090] In the illustrated embodiment, the outer diameter of the shaft body 2b located in the middle part is made smaller than the outer diameters of the shaft bodies 2a and 2c. In addition, fitting holes for fitting and fixing the shaft body 2b are respectively formed on the shaft body 2b side of the shaft body 2a and on the shaft body 2b side of the shaft body 2c.

[0091] Thus, the shaft body 2b can be fitted and fixed to the shaft body 2a from the axial extension direction, and the shaft body 2c can be fitted and fixed to the shaft body 2b from the axial extension direction to form a single fixed shaft. Therefore, when the rotational motion transmission mechanism for outputting the rotational motion of the rotating part (rotor) to the outside of the coreless motor is built into the interior of the miniaturized coreless motor, it is easy to assemble.

[0092] Although not shown, it may also be as follows: the rod-shaped shafts 2a, 2b, and 2c have the same outer diameter, fitting holes with the same small diameter as described above are formed on the shaft 2b side of the shaft 2a and the shaft 2b side of the shaft 2c, respectively, and fitting protrusion portions with a small diameter that are respectively fitted and fixed to the fitting holes are formed at both ends of the central shaft 2b. In this case, similar to Embodiment 1 ( Figure 1 ), the fixed shaft passing through the coreless motor has the same diameter throughout its entire length, but even so, it is easy to assemble.

[0093] In the coreless motor 21 of the present embodiment, the inner side in the radial direction of the rotor 8 that is rotatably supported by the fixed shaft is provided with a high-speed side sun gear on the outer periphery of the left end side that extends in the Figure 3 leftward direction. It is also possible to adopt a structure in which a plurality of rod-shaped shafts are axially fitted and fixed together to form a fixed shaft. As Figure 3 shown, the portion that rotatably supports the part of the rotor that becomes the high-speed side sun gear can be a shaft with a small diameter. In this case, the high-speed side sun gear can be made larger than Figure 1 the embodiment shown.

[0094] <Other Embodiments>

[0095] Figures 4 to 7 The embodiment shown is the same as the embodiment described using Figure 1 , Figure 3 and is a coreless motor having the following structure.

[0096] The fixed shaft 2 extends axially through the center of the coreless motor 1 and penetrates the coreless motor 1.

[0097] The cylindrical coil 4 is arranged concentrically with respect to the fixed shaft 2, one end face is supported by the stator 3, and it extends in the direction in which the fixed shaft 2 extends.

[0098] The rotor 8 is arranged concentrically with respect to the fixed shaft 2, is composed of a cylindrical inner yoke and an outer yoke, and is rotatably supported by the fixed shaft 2 on the center side in the radial direction. The inner yoke and the outer yoke sandwich the cylindrical coil 4 between them in the radial direction, and a magnet 7 is provided on one side surface facing the other side, and a magnetic circuit is formed between them.

[0099] The cylindrical housing 10 has a cylindrical portion 9 arranged concentrically with respect to the fixed shaft 2 on the outside in the radial direction of the outer yoke, and the cylindrical portion 9 rotates around the fixed shaft 2.

[0100] A rotational motion transmission mechanism is provided inside the cylindrical housing 10 to transmit the rotational motion of the rotor 8 centered on the fixed shaft 2 to the cylindrical housing 10.

[0101] The basic mechanism is the same as that of the above-described Figures 1 to 3 Embodiments 1 and 2. Therefore, for the common parts, the common reference numerals are marked and the description of their mechanisms is omitted.

[0102] In Figure 4 the illustrated ironless motor, the rotational motion transmission mechanism includes a first-stage sun gear 11a, a second-stage sun gear 11b, and a third-stage sun gear 11c, all of which are configured to be rotatable relative to the fixed shaft 2. The rotational motion of the rotor 8 is transmitted to the cylindrical portion 9 via the first-stage sun gear 11a, the second-stage sun gear 11b, the third-stage sun gear 11c, and the respective planetary gears and planet carriers provided around them.

[0103] Although the embodiments of the present invention have been described with reference to the drawings above, the present invention is not limited to the above embodiments and can be variously modified within the technical scope that can be grasped from the description of the claims.

[0104] Description of Reference Numerals

[0105] 1, 21 Ironless motor

[0106] 2 Fixed shaft

[0107] 2a, 2b, 2c Rod-shaped shaft bodies

[0108] 3 Stator

[0109] 4 Cylindrical coil

[0110] 5 Outer yoke

[0111] 6 Magnet

[0112] 7 Inner yoke

[0113] 8 Rotor

[0114] 9 Cylindrical portion of the cylindrical housing

[0115] 10 Cylindrical housing

[0116] 11 High-speed side sun gear

[0117] 12 High-speed side planetary gear

[0118] 13 High-speed side planet carrier

[0119] 14 Low-speed side input shaft

[0120] 15 Low-speed side sun gear

[0121] 16 Idler gear (low-speed side planetary gear)

[0122] 17 Low-speed side planet carrier

[0123] 20 Gear housing flange

Claims

1. A coreless motor, wherein, Comprising: A shaft, which is an integral shaft extending through the coreless motor at the center of the coreless motor; A cylindrical coil, which is arranged concentrically with respect to the shaft, one end face of which is supported by the stator, extends in the direction of the shaft and is stationary; A rotor, which is arranged concentrically with respect to the shaft, is composed of a cylindrical inner yoke and an outer yoke, and is rotatably supported by the shaft on the center side in the radial direction. The cylindrical inner yoke and the outer yoke sandwich the cylindrical coil between them in the radial direction, and a magnet is provided on one side surface opposite to the other side surface to form a magnetic circuit between them; A cylindrical housing, which has a cylindrical portion arranged concentrically with respect to the shaft on the outside of the outer yoke in the radial direction, and the cylindrical portion rotates around the shaft; and A rotational motion transmission mechanism, which is arranged inside the cylindrical housing on the radial direction of the cylindrical coil, and outputs the rotational motion of the rotor around the shaft to the cylindrical housing at a position inside the cylindrical coil in the radial direction, thereby transmitting and outputting it to the outside of the coreless motor; The rotational motion transmission mechanism is composed of a gear mechanism having a plurality of gear components at a position inside the cylindrical coil in the radial direction. The high-speed side sun gear in the gear mechanism is penetrated by the shaft and rotatably supported by the shaft, The shaft penetrates through the cylindrical housing to support the cylindrical housing.

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