Rotary support device for aircraft and rotary drive device for aircraft

Abstract

The present invention provides a rotating support device for an aircraft that facilitates ensuring the responsiveness of the drive motor and the moment rigidity of the part that rotates and supports the propeller. [Solution] The rotating support device 1 for the aircraft is assembled between an inner rotor type drive motor 3 and a propeller 4 positioned on one axial side of the drive motor 3. The rotating support device 1 for the aircraft comprises a stationary body 16 having double rows of outer ring raceways 19a, 19b on its inner circumferential surface and supported by a motor housing 5 or another member supported by the motor housing 5; a rotating body 17 having double rows of inner ring raceways 20a, 20b on its outer circumferential surface, on which the propeller 4 is supported on one axial side and which is connected to the motor output shaft 6 directly or via another member to transmit torque; and balls 18a, 18b arranged in multiples for each row between the double rows of outer ring raceways 19a, 19b and the double rows of inner ring raceways 20a, 20b.

Description

[Technical Field]

[0001] This disclosure relates to a rotary support device for an aircraft for supporting the propeller of an aircraft, and a rotary drive device for an aircraft for rotating the propeller. [Background technology]

[0002] A flying object such as a drone comprises an airframe, multiple propellers, each for generating upward lift, and a rotary drive device for the flying object, one for each propeller, which rotatably supports the propeller relative to the airframe and drives it to rotate.

[0003] As described in Japanese Patent Publication No. 2020-072530 and others, a conventional rotary drive device for an aircraft consists of a rotary support device for an aircraft comprising a stationary body, a rotating body, and bearings, and a drive motor comprising a motor stator and a motor rotor.

[0004] The stationary body is supported and fixed to the aircraft frame of the flying vehicle.

[0005] The rotating body is supported by the bearings to rotate freely around a central axis oriented in the vertical direction relative to the stationary body.

[0006] The bearing is comprised of a pair of single-row ball bearings arranged axially spaced apart between the inner surface of the stationary body and the outer surface of the rotating body. Each of the single-row ball bearings comprising the pair comprises an outer ring fitted inside the stationary body, an inner ring fitted outside the rotating body, and a plurality of balls rotatably arranged between the outer ring and the inner ring.

[0007] The motor stator is cylindrical in shape and is fitted and fixed to the outer surface of the stationary body.

[0008] The motor rotor is positioned around the motor stator, coaxially with the motor stator, and capable of relative rotation to the motor stator. The motor rotor is supported and fixed to the rotating body by a yoke.

[0009] The yoke comprises a hollow disc-shaped side plate portion fitted and fixed to one axial side portion of the rotating body, and a cylindrical portion extending from the radially outer end of the side plate portion toward the other axial side. The motor rotor is fitted and fixed to the inner circumferential surface of the cylindrical portion.

[0010] The propeller of the aircraft is supported and fixed to one end of the rotating body on the axial side such that its rotational axis coincides with the central axis of the rotating body. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] Japanese Patent Publication No. 2020-072530 [Overview of the project] [Problems that the invention aims to solve]

[0012] Drones and other flying objects change their flight direction and speed by individually varying the rotation speed of multiple propellers, and maintain a stable attitude in the air regardless of external forces such as wind. Therefore, from the perspective of properly performing these operations, it is important to ensure sufficient responsiveness of the drive motors that make up the rotary drive system for flying objects, that is, the ability to instantaneously change the rotation speed of the motor rotor.

[0013] However, the drive motor constituting the rotary drive device for an aircraft described in Japanese Patent Publication No. 2020-072530 is an outer rotor type in which the motor rotor is positioned radially outside the motor stator, and the outer diameter of the motor rotor is large. In other words, because the moment of inertia of the motor rotor is large, it is difficult to ensure the responsiveness of the drive motor.

[0014] By using an inner-rotor type motor, where the motor rotor is positioned radially inside the motor stator, the outer diameter of the motor rotor can be reduced compared to using an outer-rotor type motor. In other words, the moment of inertia of the motor rotor can be reduced, making it easier to ensure the responsiveness of the drive motor.

[0015] In this case, specifically as shown in Figure 4, it is conceivable to support the propeller 102 at one axial end of the motor output shaft 101 that constitutes the inner rotor type drive motor 100.

[0016] The inner rotor type drive motor 100 comprises a motor output shaft 101, a motor housing 103, a motor rotor 104, and a motor stator 105.

[0017] The motor housing 103 is cylindrical with closed openings on both axial sides and is supported and fixed to the aircraft's airframe. Although detailed illustrations are omitted, the motor housing 103 is constructed by combining multiple parts, and in the process of combining these parts, the motor stator 105 and motor rotor 104 can be housed inside the motor housing 103, and the motor output shaft 101 can be assembled to be rotatably supported.

[0018] The motor output shaft 101 is rotatably supported by a pair of radial bearings 106a and 106b, which are spaced apart in the axial direction inside the motor housing 103. In this configuration, one axial end of the motor output shaft 101, on which the propeller 102 is supported, protrudes outside the motor housing 103.

[0019] The motor rotor 104 is externally fitted and fixed to the portion of the motor output shaft 101 located between a pair of radial bearings 106a and 106b in the axial direction, so as to rotate integrally with the motor output shaft 101.

[0020] The motor stator 105 is arranged coaxially and rotatably relative to the motor rotor 104 around the motor rotor 104, and is fitted and fixed to the inner peripheral surface of the motor housing 103.

[0021] By adopting such a structure, the outer diameter of the motor rotor 104 can be reduced, that is, the moment of inertia of the motor rotor 104 can be reduced, so it is easy to ensure the responsiveness of the driving motor 100.

[0022] By the way, in order to increase the size of the aircraft and improve the maximum payload, it is effective to increase the output of the driving motor and increase the size of the propeller to increase the thrust generated by the propeller. However, when the size of the propeller is increased, the gyro moment load applied to the part that rotationally supports the propeller becomes large when the attitude of the aircraft changes in the air. Therefore, it is necessary to sufficiently ensure the moment rigidity of the part that rotationally supports the propeller.

[0023] However, in the structure shown in FIG. 4, the propeller 102 is directly supported by the motor output shaft 101 of the driving motor 100. The driving motor 100 usually mainly aims to generate a rotational driving force, and the moment rigidity of the motor output shaft 101 is not very high. Therefore, in order to sufficiently ensure the moment rigidity of the part that rotationally supports the propeller 102, it is necessary to increase the outer diameter of the motor output shaft 101, etc., and there is a problem that a general-purpose motor cannot be used as the driving motor 100.

[0024] An object of the present disclosure is to provide a rotary support device for an aircraft and a rotary drive device for an aircraft that are easy to ensure the responsiveness of a driving motor and the moment rigidity of a part that rotationally supports a propeller.

Means for Solving the Problems

[0025] A rotating support device for an aircraft according to one aspect of the present disclosure is assembled between a motor housing supported by the aircraft's airframe, a motor output shaft rotatably supported by the motor housing, and a motor rotor fixed to the motor output shaft, an inner rotor type drive motor having a motor stator arranged around the motor rotor and fixed to the motor housing, and a propeller positioned on one axial side of the drive motor.

[0026] A rotating support device for an aircraft according to one aspect of the present disclosure is: A stationary body having a double row of outer ring raceways on its inner circumferential surface, and supported directly to the motor housing or via other members supported by the motor housing, A rotating body having double rows of inner ring raceways on its outer circumference, the propeller being supported on one axial side, and connected to the motor output shaft directly or via another member to transmit torque, The system comprises, between the double-row outer ring raceway and the double-row inner ring raceway, multiple balls arranged in each row.

[0027] In a rotating support device for an aircraft according to one aspect of the present disclosure, the stationary body may have a stationary flange that protrudes radially outward from the other axial end and supports the stationary body with respect to the motor housing or other members supported by the motor housing.

[0028] In a rotating support device for an aircraft according to one aspect of the present disclosure, the rotating body may have a rotating flange that protrudes radially outward from a portion located axially to one side of the stationary body, and on which the propeller is supported.

[0029] In a rotating support device for an aircraft according to one aspect of the present disclosure, the rotating body may have spline holes for spline-engaging a spline shaft portion provided on the motor output shaft or a rotating member connected to the motor output shaft in a torque-transmitting manner.

[0030] A rotary drive device for an aircraft according to one aspect of the present disclosure is: An inner rotor type drive motor having a motor housing supported by the aircraft's airframe, a motor output shaft rotatably supported by the motor housing, a motor rotor fixed to the motor output shaft, and a motor stator arranged around the motor rotor and fixed to the motor housing, The system includes a rotating support device for an aircraft, which is positioned on one side of the axial direction of the aforementioned drive motor.

[0031] In particular, in a rotary drive device for an aircraft according to one aspect of the present disclosure, the rotary support device for the aircraft is comprised of the rotary support device for an aircraft according to one aspect of the present disclosure, wherein the stationary body is supported by the motor housing or other members supported by the motor housing, and the rotating body is connected to the motor output shaft directly or via other members in a manner that allows for torque transmission.

[0032] A rotary drive device for an aircraft according to one aspect of the present disclosure may further include a reduction gear, and the motor output shaft may be connected to the rotating body via the reduction gear in a manner that transmits torque. [Effects of the Invention]

[0033] According to one aspect of the present disclosure, a rotary support device for an aircraft and a rotary drive device for an aircraft make it easier to ensure the responsiveness of the drive motor and the moment rigidity of the part that supports the rotation of the propeller. [Brief explanation of the drawing]

[0034] [Figure 1] Figure 1 is a cross-sectional view of a rotary drive device for an aircraft, which is a first example of an embodiment of the present disclosure. [Figure 2] Figure 2 is a cross-sectional view of the first example of a rotating support device for an aircraft. [Figure 3] Figure 3 is a cross-sectional view of a rotary drive device for an aircraft, which is a second example of an embodiment of the present disclosure. [Figure 4] Figure 4 is a cross-sectional view of the rotary drive device for the aircraft that was considered earlier. [Modes for carrying out the invention]

[0035] [Example 1] A first example of an embodiment of the present disclosure will be described with reference to Figures 1 and 2.

[0036] The aircraft to which the Rotary Support Device and Rotary Drive Device for Aircraft of this Disclosure can be applied are not limited to drones or other aircraft, regardless of whether they are unmanned or manned, or small or large.

[0037] The rotating support device 1 for the aircraft constitutes a part of the rotating drive device 2 for the aircraft. Specifically, the rotating drive device 2 for the aircraft comprises an inner rotor type drive motor 3 and the rotating support device 1 for the aircraft. The rotating drive device 2 for the aircraft is used to rotatably support the propeller 4 of the aircraft relative to the aircraft's airframe and to drive it to rotate.

[0038] In this disclosure, unless otherwise specified, the axial, radial, and circumferential directions refer to the axial, radial, and circumferential directions of the rotating support device 1 for the aircraft. The axial, radial, and circumferential directions of the rotating support device 1 for the aircraft coincide with the axial, radial, and circumferential directions of the drive motor 3. Furthermore, one axial side refers to the upper side of Figures 1 and 2, and the other axial side refers to the lower side of Figures 1 and 2.

[0039] The drive motor 3 comprises a motor housing 5, a motor output shaft 6, a motor rotor 7, and a motor stator 8.

[0040] The motor housing 5 is supported and fixed to the aircraft frame. The motor housing 5 can have any configuration as long as it is supported by the aircraft frame, houses the motor rotor 7 and motor stator 8 inside, and rotatably supports the motor output shaft 6.

[0041] In this example, the motor housing 5 is configured as a cylindrical shape with openings on both axial sides closed. The motor housing 5 is constructed by combining multiple parts, and in the process of combining these parts, it is possible to house the motor stator 8 and motor rotor 7 inside the motor housing 5 and assemble it so as to rotatably support the motor output shaft 6.

[0042] In this example, the motor housing 5 comprises a bottomed cylindrical housing body 9 and a hollow circular flat plate lid 10. The housing body 9 comprises a cylindrical tube portion 11 and a circular flat plate bottom portion 12 that closes the opening on the other axial side of the tube portion 11. The bottom portion 12 has a recess 13 in the radial center of one axial side surface. The recess 13 has a circular opening shape when viewed from the axial side. The lid 10 is fixed to the axial end of the tube portion 11 by screws or the like so as to close the opening on one axial side of the tube portion 11.

[0043] The motor output shaft 6 is rotatably supported by the motor housing 5. In this example, the motor output shaft 6 is cylindrical and rotatably supported by a pair of radial bearings 14a and 14b arranged axially spaced apart inside the motor housing 5. In this state, one axial end of the motor output shaft 6 protrudes outside the motor housing 5. That is, the motor output shaft 6 is rotatably supported by the motor housing 5 by the radial bearing 14a on the one axial side, with respect to the inner circumferential surface of the cover 10, and by the radial bearing 14b on the other axial side, with respect to the inner circumferential surface of the recess 13. The pair of radial bearings 14a and 14b can each be, for example, radial ball bearings, although this is not limited to these.

[0044] The motor rotor 7 is fixed to the motor output shaft 6. Specifically, the motor rotor 7 is cylindrical in shape, and the outer surface of the motor rotor 7 has alternating south poles and north poles arranged in the circumferential direction. The motor rotor 7 is externally fitted and fixed to the portion of the motor output shaft 6 located between a pair of radial bearings 14a and 14b in the axial direction, so as to rotate together with the motor output shaft 6.

[0045] The motor stator 8 is positioned around the motor rotor 7 and fixed to the motor housing 5. Specifically, the motor stator 8 includes a core made of magnetic material and a coil wound around the core, and is configured as a cylinder overall, with magnetic poles provided at multiple equally spaced locations in the circumferential direction on its inner surface. The motor stator 8 is positioned around the motor rotor 7 so as to be rotatable coaxially and relative to the motor rotor 7, and is fitted and fixed to the inner surface of the cylindrical portion 11.

[0046] In the drive motor 3, when current is supplied to the coils constituting the motor stator 8, an electromagnetic force is generated between the multiple magnetic poles of the motor stator 8 and the multiple S poles and N poles of the motor rotor 7, causing the motor rotor 7 to rotate relative to the motor stator 8, and thus the motor output shaft 6 is rotated.

[0047] The rotating support device 1 for the aircraft is assembled between an inner rotor type drive motor 3 and a propeller 4 positioned on one axial side of the drive motor 3. The rotating support device 1 for the aircraft comprises a stationary body 16, a rotating body 17, and a plurality of balls 18a, 18b.

[0048] The stationary body 16 has double rows of outer ring raceways 19a and 19b on its inner circumferential surface and is supported by the motor housing 5 or other members supported by the motor housing 5. For example, if the rotating body 17 is connected to the motor output shaft 6 directly or via a coupling, the stationary body 16 is supported by the motor housing 5 directly or via other members such as spacers. On the other hand, if the rotating body is connected to the motor output shaft via a reduction gear, the stationary body is supported by the motor housing via a gear housing that accommodates the reduction gear. In any case, the stationary body 16 is indirectly supported by the aircraft frame and does not rotate even when the propeller 4 rotates.

[0049] The rotating body 17 has double rows of inner ring raceways 20a and 20b on its outer circumference, a propeller 4 is supported on one axial side, and is connected to the motor output shaft 6 directly or via other components to transmit torque. That is, the rotating body 17 is rotationally driven based on the rotational drive of the motor output shaft 6 and rotates together with the propeller 4. In this example, the rotating body 17 is directly connected to the motor output shaft 6.

[0050] Multiple balls 18a and 18b are positioned between the double-row outer ring raceways 19a and 19b and the double-row inner ring raceways 20a and 20b, in each row. As a result, the rotating body 17 is rotatably supported radially inward of the stationary body 16.

[0051] The stationary body 16 can adopt a configuration in which at least one of the double-row outer ring raceways 19a, 19b is directly formed on the inner surface of the stationary body 16.

[0052] For example, the stationary body 16 may be composed solely of an annular stationary support member, with double-row outer ring raceways 19a and 19b both formed on the inner circumferential surface of the stationary support member.

[0053] Alternatively, the stationary body 16 may be configured to include an annular stationary support member having one of the double-row outer ring raceways 19a and 19b on its inner circumferential surface, and a single outer ring having the other of the double-row outer ring raceways 19a and 19b on its inner circumferential surface and fitted into the stationary support member, such that the inner circumferential surface of the stationary body 16 includes the inner circumferential surface of the stationary support member and the inner circumferential surface of the single outer ring.

[0054] Alternatively, the stationary body 16 may be configured to include an annular stationary support member and two outer rings, each having outer ring raceways 19a and 19b on its inner circumferential surface, and fitted into the stationary support member.

[0055] In this example, the stationary body 16 is composed solely of an annular stationary support member 21, and the double-row outer ring raceways 19a and 19b are both formed on the inner circumferential surface of the stationary support member 21.

[0056] The rotating body 17 can adopt a configuration in which at least one of the double-row inner ring raceways 20a, 20b is directly formed on the outer surface of the rotating body 17.

[0057] For example, the rotating body 17 may be composed solely of a rotating support member, and a configuration may be adopted in which both of the double-row inner ring raceways 20a and 20b are formed on the outer circumferential surface of the rotating support member.

[0058] Alternatively, the rotating body 17 may be configured to include a rotating-side support member having one of two rows of inner ring raceways 20a and 20b on its outer circumferential surface, and a single inner ring having the other of two rows of inner ring raceways 20a and 20b on its outer circumferential surface and fitted onto the rotating-side support member, such that the outer circumferential surface of the rotating body 17 includes the outer circumferential surface of the rotating-side support member and the outer circumferential surface of the single inner ring.

[0059] Alternatively, the rotating body 17 may be configured to include a rotating side support member and two inner rings, each having inner ring raceways 200a and 20b on its outer circumference, and fitted onto the rotating side support member.

[0060] In this example, the rotating body 17 comprises a rotating-side support member 22 and one inner ring 23 fitted onto the rotating-side support member 22. The outer circumferential surface of the rotating body 17 includes the outer circumferential surface of the rotating-side support member 22 and the outer circumferential surface of the one inner ring 23. The inner ring raceway 20a on one axial side is formed on the outer circumferential surface of the rotating-side support member 22, and the inner ring raceway 20b on the other axial side is formed on the outer circumferential surface of the inner ring 23.

[0061] As described above, the rotating support device 1 for an aircraft in this example employs at least one of the following configurations (in this example, both configurations): one in which at least one of the double-row outer ring raceways 19a, 19b is directly formed on the inner circumferential surface of the stationary body 16, and another in which at least one of the double-row inner ring raceways 20a, 20b is directly formed on the outer circumferential surface of the rotating body 17. For this reason, compared to a different structure from this example, namely, a different structure in which the stationary body 16 comprises an annular stationary support member and two outer rings fitted inside the stationary support member, each having outer ring raceways 19a, 19b on their respective inner circumferential surfaces, and the rotating body 17 comprises a rotating support member and two inner rings fitted outside the rotating support member, each having inner ring raceways 20a, 20b on their respective outer circumferential surfaces.

[0062] In other words, in the structure of the alternative example described above, there is a tolerance between the outer diameter of the outer ring and the inner diameter of the inner ring arranged in each row, and there is also a tolerance in the radial width of the portion between the inner surface of the stationary body and the outer surface of the rotating body in which the outer ring and inner ring are arranged. As a result, the cumulative tolerances when the components constituting the rotating support device for aircraft are combined become large, and the degree of coaxiality between the stationary body and the rotating body tends to decrease.

[0063] In contrast, in the rotating support device 1 for aircraft in this example, at least one of the double-row outer ring raceways 19a and 19b (in this example, both of the double-row outer ring raceways 19a and 19b) is formed directly on the inner surface of the stationary body 16, and at least one of the double-row inner ring raceways 20a and 20b (in this example, the inner ring raceway 20a on one axial side) is formed directly on the outer surface of the rotating body 17. In this rotating support device 1 for aircraft in this example, at least one outer ring (in this example, two outer rings) and at least one inner ring (in this example, one inner ring) can be omitted compared to the structure of the other example, so the cumulative tolerance when combining the parts that make up the rotating support device 1 for aircraft can be kept small. Therefore, it is easier to ensure coaxiality between the stationary body 16 and the rotating body 17. As a result, it is easier to suppress the rotational runout of the propeller 4 supported by the rotating body 17.

[0064] Furthermore, in the rotating support device 1 for the aircraft in this example, at least one outer ring (two outer rings in this example) and at least one inner ring (one inner ring in this example) can be omitted. Therefore, compared to the structure of the other example, it is easier to reduce the weight by keeping the radial thickness of the stationary body 16 and the rotating body 17 smaller, and it is also easier to keep the outer diameter of the stationary body 16 smaller. In other words, it is easier to make the rotating support device 1 for the aircraft smaller and lighter.

[0065] The stationary body 16 (stationary side support member 21) is made of a hard metal such as an iron alloy. The double-row outer ring raceways 19a and 19b each have an arc-shaped generatrix.

[0066] In this example, the stationary body 16 has a cylindrical shoulder portion 24a on its inner circumferential surface in the portion adjacent to the other axial side of the outer ring raceway 19a on one axial side, and a cylindrical shoulder portion 24b on its inner circumferential surface in the portion adjacent to the one axial side of the outer ring raceway 19b on the other axial side. In this example, the portion of the inner circumferential surface of the stationary body 16 located between the double rows of outer ring raceways 19a and 19b is composed of a cylindrical surface whose inner diameter does not change with respect to the axial direction, and the respective shoulder portions 24a and 24b are composed of the axial ends of this cylindrical surface.

[0067] Groove shoulder height H on the load side of the outer ring raceway 19a on one axial side 24a In other words, the radial height from the groove bottom, which is the maximum diameter portion of the outer ring raceway 19a on one axial side, to the shoulder portion 24a adjacent to the other axial side of the outer ring raceway 19a on the one axial side, is 25% or more of the diameter Da of the ball 18a in the axial row on one axial side that rolls and contacts the outer ring raceway 19a on the one axial side. Groove shoulder height H 24a While not limited to this, it is preferable that the diameter of the ball 18a be 30% to 50%, and more preferably 38% to 50%.

[0068] Groove shoulder height H on the load side of the outer ring raceway 19b on the other axial side 24b That is, the radial height from the groove bottom, which is the maximum diameter portion of the outer ring raceway 19b on the other axial side, to the shoulder portion 24b adjacent to the axial side of the outer ring raceway 19b on the other axial side, is 25% or more of the diameter Db of the ball 18b of the axial side row that rolls and contacts the outer ring raceway 19b on the other axial side. Groove shoulder height H 24b While not limited to this, it is preferable that the diameter of the ball 18b be 30% to 50% of the diameter Db, and more preferably 38% to 50%.

[0069] In this example, the stationary body 16 has a cylindrical counterbore portion 25a on its inner circumferential surface in the portion adjacent to the axial side of the outer ring raceway 19a on one axial side, and a cylindrical counterbore portion 25b on its inner circumferential surface in the portion adjacent to the axial side of the outer ring raceway 19b on the other axial side. The inner diameter of the counterbore portion 25a on the axial side is the same as the groove bottom diameter of the outer ring raceway 19a on the axial side, or slightly smaller than the groove bottom diameter of the outer ring raceway 19a on the axial side. The inner diameter of the counterbore portion 25b on the other axial side is the same as the groove bottom diameter of the outer ring raceway 19b on the other axial side, or slightly smaller than the groove bottom diameter of the outer ring raceway 19b on the other axial side.

[0070] In this example, the stationary body 16 is directly supported by the motor housing 5. In this example, the stationary body 16 has a stationary flange 26 that protrudes radially outward from the other axial end and is used to support the stationary body 16 against the motor housing 5. The stationary flange 26 has flange-side support holes 27 that penetrate axially at multiple circumferential locations in the radially intermediate part.

[0071] The stationary body 16 is directly supported and fixed to the motor housing 5 by screwing a support bolt, which is a connecting member inserted through the flange-side support hole 27, into a motor-side support hole (not shown) provided in the cover 10 that constitutes the motor housing 5.

[0072] The rotating support member 22 and inner ring 23 that constitute the rotating body 17 are each made of a hard metal such as an iron alloy. The double-row inner ring raceways 20a and 20b each have an arc-shaped generatrix.

[0073] In this example, the inner ring raceway 20a on one axial side is formed on the outer circumferential surface of the axial intermediate portion of the rotating support member 22. The rotating support member 22 has a cylindrical shoulder portion 28a on its outer circumferential surface in the portion adjacent to the axial side of the inner ring raceway 20a on one axial side.

[0074] In this example, the rotating support member 22 has a small-diameter stepped portion 29 on its outer circumferential surface, located on the axial side of the inner ring raceway 20a on one axial side, with a smaller outer diameter than the portion adjacent to the axial side, into which the inner ring 23 is fitted. The rotating support member 22 has a stepped surface 30 facing the axial side at the axial end of the small-diameter stepped portion 29, and a male threaded portion 31 on its outer circumferential surface, adjacent to the axial side of the small-diameter stepped portion 29, into which a nut 32 is screwed.

[0075] In this example, the inner ring raceway 20b on the other axial side is formed on the outer circumferential surface of the axial intermediate portion of the inner ring 23. The inner ring 23 has a cylindrical shoulder portion 28b on its outer circumferential surface in the portion adjacent to the other axial side of the inner ring raceway 20b on the other axial side.

[0076] In this example, the groove shoulder height H on the load side of the inner ring raceway 20a on one axial side is 28a Specifically, the radial height from the groove bottom, which is the smallest diameter portion of the inner ring raceway 20a on one axial side, to the shoulder portion 28a adjacent to the inner ring raceway 20a on one axial side is 25% or more of the diameter Da of the ball 18a in the axial row on one axial side that rolls and contacts the inner ring raceway 20a on one axial side. Groove shoulder height H 28a While not limited to this, it is preferable that the diameter of the ball 18a be 30% to 50%, and more preferably 38% to 50%.

[0077] In this example, the groove shoulder height H on the load side of the inner ring raceway 20b on the other axial side 28b That is, the radial height from the groove bottom, which is the smallest diameter portion of the inner ring raceway 20b on the other axial side, to the shoulder portion 28b adjacent to the inner ring raceway 20b on the other axial side is 25% or more of the diameter Db of the ball 18b of the axial side row that rolls and contacts the inner ring raceway 20b on the other axial side. Groove shoulder height H 28b While not limited to this, it is preferable that the diameter of the ball 18b be 30% to 50% of the diameter Db, and more preferably 38% to 50%.

[0078] The rotating body 17 is constructed by fitting the inner ring 23 onto the small-diameter stepped portion 29 of the rotating support member 22, and by sandwiching the inner ring 23 from both axial sides between the stepped surface 30 of the rotating support member 22 and the axial side of a nut 32 screwed onto the male threaded portion 31 of the rotating support member 22, thereby connecting and fixing the rotating body 17 to the rotating support member 22 and the inner ring 23. In the rotating support device 1 for aircraft in this example, the rotating body 17 is constructed by connecting and fixing the rotating support member 22 and the inner ring 23, making it possible to adjust the preload applied to the balls 18a and 18b to an appropriate size.

[0079] When implementing this disclosure, instead of a nut, a configuration can be adopted in which a crimped portion is formed by plastically deforming the axial end of the rotating support member that protrudes from the other axial end face of the inner ring radially outward, and the rotating support member and the inner ring are joined and fixed by pressing the other axial end face of the inner ring with the crimped portion.

[0080] The axial portion of the rotating body 17 that supports the propeller 4 is not limited in shape as long as it can support the propeller 4. For example, the axial portion of the rotating body 17 can have a shape that allows the propeller 4 to be fitted onto it in a way that prevents relative rotation, or it can have a shape that includes a rotating flange for supporting the propeller 4.

[0081] In this example, the rotating body 17 has a rotating flange 33 that protrudes radially outward from a portion located axially to one side of the stationary body 16 and supports the propeller 4. In this example, the rotating flange 33 is provided at one axial end of the rotating side support member 22 and is configured as a hollow circular flat plate. The rotating flange 33 has mounting holes 34 that penetrate axially through multiple locations in the circumferential direction in the radial middle section.

[0082] The mounting hole 34 is configured as either a threaded hole or a press-fit hole. If the mounting hole 34 is configured as a threaded hole, the propeller 4 is connected and fixed to the rotating flange 33 by screwing bolts, which are inserted through through holes (not shown) located at multiple circumferential locations on the radially inner part of the propeller 4, into the mounting hole 34 from one axial side. If the mounting hole 34 is configured as a press-fit hole, a stud is press-fitted into the mounting hole 34 from the other axial side. The propeller 4 is connected and fixed to the rotating flange 33 by inserting the stud through through holes (not shown) located at multiple circumferential locations on the radially inner part of the propeller 4 and screwing nuts onto the tips of the studs. In this example, the mounting hole 34 is configured as a threaded hole.

[0083] The structure for connecting the rotating body 17 and the motor output shaft 6 in a torque-transmitting manner is not particularly limited. The rotating body 17 and the motor output shaft 6 can be connected directly or via a coupling, reduction gear, etc., as long as they can be connected in a torque-transmitting manner.

[0084] In this example, the rotating body 17 has spline holes 35 for spline engagement with a spline shaft portion 15 provided on the motor output shaft 6 or a rotating member (for example, the output member 43 described later) that is connected to the motor output shaft 6 in a manner that can transmit torque.

[0085] In this example, the spline hole 35 is provided in the rotating support member 22. Specifically, the rotating support member 22 has a central hole 36 that penetrates the radial center in the axial direction, and the other half of the central hole 36 on the axial side is composed of a spline hole 35 having a female spline portion on its inner circumferential surface in which concave and convex portions are alternately arranged in the circumferential direction. The spline shaft portion 15 is provided at one end on the axial side of the motor output shaft 6 and is spline-engaged with the spline hole 35. As a result, the rotating body 17 is connected to the motor output shaft 6 in a manner that allows torque to be transmitted.

[0086] Balls 18a and 18b are made of metals such as iron alloys or ceramics.

[0087] In this example, the balls 18a and 18b in each row are provided with a back-to-back (DB) type contact angle θ and a predetermined amount of preload. The magnitude of the contact angle θ can be arbitrarily determined within a range that ensures the required bearing rigidity, for example, between 1° and 45°. The magnitude of the contact angle θ is not limited to this, but it is preferably between 15° and 45°, and more preferably between 15° and 42°. In this example, the balls 18a and 18b in each row are held to roll freely by cages 37a and 37b.

[0088] In this example, a predetermined amount of preload is applied to the balls 18a and 18b in each row by bringing one axial end face of the inner ring 23 into contact with the stepped surface 30 of the rotating support member 22, and by restricting the force that presses the other axial end face of the inner ring 23 against the nut 32. Furthermore, if a structure is adopted in which a crimped portion formed at the other axial end of the rotating support member presses against the other axial end face of the inner ring, a predetermined amount of preload can be applied to the rolling elements in each row by restricting the force that presses against the other axial end face of the inner ring against the crimped portion.

[0089] In the rotating support device 1 for aircraft in this example, the diameters of the balls 18a in one axial row and the diameters of the balls 18b in the other axial row are equal. However, when implementing the rotating support device for aircraft of this disclosure, the diameters of the balls 18a in one axial row and the diameters of the balls 18b in the other axial row can be made different. Furthermore, the rotating support device 1 for aircraft in this example has a so-called equal-diameter PCD type structure in which the pitch circle diameters of the balls 18a in one axial row and the pitch circle diameters of the balls 18b in the other axial row are equal. However, the rotating support device for aircraft of this disclosure can also be applied to a so-called different-diameter PCD type structure in which the pitch circle diameters of the balls 18a and 18b in each row are different.

[0090] The rotating support device 1 for the aircraft in this example further includes, as optional elements, a one-side sealing device 39 that closes the opening on one axial side of the rolling element installation space 38 located between the inner circumferential surface of the stationary body 16 and the outer circumferential surface of the rotating body 17, and a other-side sealing device 40 that closes the opening on the other axial side of the rolling element installation space 38. This prevents or suppresses foreign matter from the external space from entering the rolling element installation space 38 through the openings on both axial sides of the rolling element installation space 38, and prevents grease sealed in the rolling element installation space 38 from leaking into the external space.

[0091] Each of the one - side sealing device 39 and the other - side sealing device 40 may be a contact - type seal or a non - contact - type seal. As the contact - type seal, for example, a seal ring having a seal lip supported by the stationary body 16 and slidably contacting the surface of the rotating body 17, or a combination seal ring formed by combining a sliding contact ring fixed to the rotating body 17 and a seal ring having a seal lip supported by the stationary body 16 and slidably contacting the surface of the sliding contact ring can be adopted. Further, as the non - contact - type seal, for example, a seal ring (shield plate) supported by the stationary body 16 and having a part thereof facing the surface of the rotating body 17 in proximity can be adopted.

[0092] According to the rotary drive device 2 for the flying object of this example, it is easy to ensure the responsiveness of the drive motor 3 and the moment rigidity of the part that rotatably supports the propeller 4.

[0093] That is, in the rotary drive device 2 for the flying object of this example, as the drive motor 3, an inner - rotor type in which the motor rotor 7 is arranged inside the motor stator 8 in the radial direction is used. Therefore, compared with the case of using an outer - rotor type in which the motor rotor is arranged outside the motor stator in the radial direction as the drive motor, the outer diameter of the motor rotor 7 can be made smaller, and the moment of inertia of the motor rotor 7 can be made smaller. Thus, it is easy to ensure the responsiveness of the drive motor 3.

[0094] Also, in the rotary drive device 2 for the flying object of this example, as the part that rotatably supports the propeller 4, a rotary support device 1 for the flying object provided separately from the drive motor is used. Therefore, it becomes easy to ensure the moment rigidity of the part that rotatably supports the propeller 4 while using a general - purpose motor without adopting special specifications such as increasing the outer diameter of the motor output shaft 6 as the drive motor 3.

[0095] In the rotary support device 1 for the flying object of this example, in each row, the groove shoulder height H on the load side of the outer - ring tracks 19a, 19b 24a、 H 24b, and the groove shoulder height H on the load side of the inner ring raceways 20a and 20b 28a H 28b However, this is set to be 25% or more of the diameter of the balls 18a and 18b. Therefore, it is possible to ensure the bearing capacity of the rotating support device 1 for aircraft for axial loads and moment loads without increasing the size of the bearing. In other words, even when a large axial load and / or moment load is applied to the rotating support device 1 for aircraft for axial loads, it is possible to make it less likely for the rolling surfaces of the balls 18a and 18b in each row to ride up onto the shoulders 24a, 24b, 28a, and 28b on the load side.

[0096] [Example 2] A second example of the embodiment of this disclosure will be described with reference to Figure 3.

[0097] The rotary drive device 2a for the aircraft in this example further includes a reduction gear 41. The motor output shaft 6a, which constitutes the drive motor 3a, is connected via the reduction gear 41 to the rotating body 17, which constitutes the rotary support device 1 for the aircraft, in a manner that allows for torque transmission. The reduction gear 41 reduces the rotational speed of the motor output shaft 6a and transmits it to the rotating body 17. In other words, the reduction gear 41 increases the torque of the motor output shaft 6a and transmits it to the rotating body 17.

[0098] The structure of the gearbox 41 is not particularly limited, but for example, a planetary gear type or a parallel shaft gear type can be adopted.

[0099] In this example, the gearbox 41 is composed of a planetary gear type gearbox. Specifically, the gearbox 41 comprises an input member 42, an output member 43, a gearbox housing 44, a sun gear 45, a ring gear 46, a plurality of planetary gears 47, and a carrier 48.

[0100] The input member 42 is formed by the motor output shaft 6a, or it is formed as a separate member from the motor output shaft 6a and connected to the motor output shaft 6a in a manner that enables torque transmission. In this example, the input member 42 is formed in a cylindrical shape and is provided coaxially and integrally with the motor output shaft 6a at one axial end of the motor output shaft 6a. However, the input member 42 can also be formed as a separate entity from the motor output shaft 6a and connected to one axial end of the motor output shaft 6a in a manner that enables torque transmission using a connecting member.

[0101] The output member 43 is connected to the rotating body 17 in a manner that allows for torque transmission. In this example, the output member 43 is cylindrical in shape and is arranged coaxially with the input member 42. One axial portion of the output member 43 is composed of a spline shaft portion 15a. The output member 43 is connected to the rotating body 17 in a manner that allows for torque transmission by spline-engaging the spline shaft portion 15a with the spline hole 35 of the rotating body 17. In this example, the output member 43 corresponds to a rotating member that is connected to the motor output shaft 6a in a manner that allows for torque transmission.

[0102] The gearbox housing 44 is cylindrical in shape with openings on both axial sides closed, and is supported and fixed to the motor housing 5. Specifically, the gearbox housing 44 has a coupling flange 49 projecting radially outward at the other axial end. The coupling flange 49 has support holes 50 that penetrate axially at multiple locations in the circumferential direction. The gearbox housing 44 is supported and fixed to the motor housing 5 by screwing support bolts, which are coupling members inserted through the support holes 50, into motor-side support holes (not shown) provided in the lid 10 that constitutes the motor housing 5. The sun gear 45, ring gear 46, multiple planetary gears 47, and carrier 48 are housed inside the gearbox housing 44.

[0103] Although detailed illustrations are omitted, the reduction gear housing 44 is constructed by combining multiple parts, and in the process of combining these parts, the sun gear 45, ring gear 46, multiple planetary gears 47, and carrier 48 can be housed inside the reduction gear housing 44.

[0104] In this example, the stationary body 16 is directly supported and fixed to the reduction gear housing 44 by screwing a support bolt, which is a connecting member inserted through the flange-side support hole 27, into a gear-side support hole (not shown) provided in the reduction gear housing 44. In other words, in this example, the stationary body 16 is supported and fixed to the motor housing 5 via the reduction gear housing 44.

[0105] The sun gear 45 is externally fitted and fixed to one axial end of the input member 42 so as to rotate integrally with the input member 42.

[0106] The ring gear 46 is positioned coaxially with the sun gear 45 around it and is fitted and fixed to the inner circumferential surface of the reduction gear housing 44.

[0107] Multiple planetary gears 47 are arranged at multiple circumferential locations between the sun gear 45 and the ring gear 46, and mesh with the sun gear 45 and the ring gear 46.

[0108] The carrier 48 is configured as a hollow circular plate and is externally fitted and fixed around the other axial end of the output member 43 so as to rotate integrally with the output member 43. Each planetary gear 47 is supported at multiple locations in the circumferential direction of the carrier 48 via planetary shafts 51 and radial bearings 52, enabling it to rotate (spin) around its own central axis. Specifically, the planetary shafts 51 are arranged parallel to the input member 42 and the output member 43, and one axial end is internally fitted and fixed in coupling holes 53 provided at multiple locations in the circumferential direction of the carrier 48. The radial bearings 52 are positioned between the outer circumferential surface of the other axial end of the planetary shaft 51 and the inner circumferential surface of the planetary gear 47.

[0109] In this example, the rotary drive device 2a for the aircraft is equipped with a reduction gear 41, making it easier to secure the rotational driving force for the propeller 4.

[0110] Furthermore, when implementing this disclosure, the reduction gear 41, which is a planetary gear type reduction gear, can be configured in any way, not limited to the above configuration, as long as it can reduce the rotation of the motor output shaft 6a (increase the torque) and transmit it to the rotating body 17. For example, the ring gear 46 can be connected to the output member 43 so as to rotate integrally with it, and the carrier 48 can be supported and fixed to the reduction gear housing 44. Alternatively, the carrier 48 can be connected to the input member 42 so as to rotate integrally with it, the ring gear 46 can be connected to the output member 43 so as to rotate integrally with it, and the sun gear 45 can be supported and fixed to the reduction gear housing 44.

[0111] The other components and effects of the second example are the same as those of the first example. [Explanation of Symbols]

[0112] 1 Rotational support device for aircraft 2, 2a Rotary drive device for aircraft 3, 3a Drive motor 4 propellers 5 Motor Housing 6, 6a Motor output shaft 7 Motor Rotor 8 Motor Stator 9 Housing body 10 Lid 11 Cylinder part 12 Bottom 13 recess 14a, 14b radial bearings 15, 15a Spline shaft 16 Stationary Objects 17. Solids of revolution 18a, 18b balls 19a, 19b Outer ring track 20a, 20b Inner ring track 21 Stationary support member 22 Rotating side support member 23 Internal 24a, 24b Shoulder 25a, 25b Counterbore section 26 Static flange 27 Flange-side support holes 28a, 28b Shoulder 29 Small diameter stepped section 30 Step surface 31 Male threaded section 32 nuts 33 Rotating flange 34 mounting holes 35 spline holes 36 Center hole 37a, 37b retainer 38 Rolling element installation space 39 One-sided sealing device 40 Other side sealing device 41 Reducer 42 Input Member 43 Output component 44 Gearbox Housing 45 Sangiya 46 Ring Gear 47 Planetary Gear 48 Carriers 49. Coupling flange 50 Support hole 51 Planetary Axis 52 Radial bearings 53 Binding hole 100 Drive motor 101 Motor output shaft 102 Propeller 103 Motor Housing 104 Motor Rotor 105 Motor Stator 106a, 106b radial bearings

Claims

1. A motor housing supported by the aircraft's airframe, a motor output shaft rotatably supported by the motor housing, and a motor rotor fixed to the motor output shaft, and an inner rotor type drive motor having a motor stator arranged around the motor rotor and fixed to the motor housing, and a propeller positioned on one axial side of the drive motor, are assembled between these two components. A rotating support device for an aircraft, A stationary body having a double row of outer ring raceways on its inner circumferential surface, and supported directly to the motor housing or via other members supported by the motor housing, A rotating body having double rows of inner ring raceways on its outer circumference, the propeller being supported on one axial side, and connected to the motor output shaft directly or via another member to transmit torque, The system comprises, between the double-row outer ring raceway and the double-row inner ring raceway, multiple balls arranged in each row. Rotation support device for aircraft.

2. The rotating support device for an aircraft according to claim 1, wherein the stationary body protrudes radially outward from the other end on the axial side and has a stationary flange for supporting the stationary body with respect to the motor housing or other members supported by the motor housing.

3. The rotating support device for an aircraft according to claim 1, wherein the rotating body has a rotating flange that protrudes radially outward from a portion located axially on one side of the stationary body and supports the propeller.

4. The rotating body has a spline hole for spline-engaging a spline shaft portion provided on the motor output shaft or a rotating member connected to the motor output shaft in a torque-transmitting manner. This is a rotating support device for an aircraft according to claim 1.

5. An inner rotor type drive motor having a motor housing supported by the aircraft's airframe, a motor output shaft rotatably supported by the motor housing, a motor rotor fixed to the motor output shaft, and a motor stator arranged around the motor rotor and fixed to the motor housing, The vehicle comprises a rotating support device for an aircraft, which is positioned on one axial side of the drive motor, The rotating support device for the aircraft is configured as the rotating support device for the aircraft according to any one of claims 1 to 4, wherein the stationary body is supported by the motor housing or other members supported by the motor housing, and the rotating body is connected to the motor output shaft directly or via other members in a manner that allows torque transmission. Rotary drive device for aircraft.

6. Equipped with a further reduction gear, The motor output shaft is connected to the rotating body via the reduction gear so as to be able to transmit torque. The rotary drive device for an aircraft according to claim 5.

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