Rotary support device for aircraft and rotary drive device for aircraft

Abstract

The present invention provides a rotary support device and a rotary drive device for an aircraft that can suppress axial rattle between a stationary body and a rotating body, and that can easily ensure moment rigidity while suppressing an increase in weight. [Solution] The device comprises a stationary body 7, a rotating body 8, and a plurality of rolling elements 9a and 9b. Each row of rolling elements 9a and 9b is provided with a back-to-back contact angle and preload, and the pitch circle diameter PCD1 of the rolling elements 9a in one row on the axial side is larger than the pitch circle diameter PCD2 of the rolling elements 9b in the other row on the axial side (PCD1 > PCD2).

Description

Technical Field

[0001] The present disclosure relates to a rotary support device for an aircraft for supporting a propeller of the aircraft, and a rotary drive device for the aircraft for rotationally driving the propeller.

Background Art

[0002] An aircraft such as a drone includes an airframe, a plurality of propellers each for obtaining an upward lift force, and a rotary drive device for the aircraft provided one by one for each propeller, for rotatably supporting the propeller with respect to the airframe and rotationally driving it.

[0003] As described in Japanese Patent Application Laid-Open No. 2020-072530 and the like, a conventional rotary drive device for an aircraft is a combination of a rotary support device for an aircraft including a stationary body, a rotating body, and a plurality of balls, and a drive motor including a motor stator and a motor rotor.

[0004] The stationary body has a double-row outer raceway on its inner peripheral surface, and is supported and fixed to the airframe of the aircraft with its central axis oriented in the vertical direction. The stationary body includes a first outer ring in which an outer raceway on one axial side of the double-row outer raceways is formed on the inner peripheral surface, a second outer ring in which an outer raceway on the other axial side of the double-row outer raceways is formed on the inner peripheral surface, and a housing for fitting and supporting the first outer ring and the second outer ring, and the housing is supported and fixed to the airframe of the aircraft.

[0005] The rotating body has a double-row inner raceway on its outer peripheral surface, and is disposed coaxially with the stationary body inside the stationary body in the radial direction. The rotating body includes a first inner ring in which an inner raceway on one axial side of the double-row inner raceways is formed on the outer peripheral surface, a second inner ring in which an inner raceway on the other axial side of the double-row inner raceways is formed on the outer peripheral surface, and a shaft member for fitting and supporting the first inner ring and the second inner ring.

[0006] Multiple balls are positioned between the double-row outer ring raceways and the double-row inner ring raceways, with several balls in each row. This allows the rotating body to be rotatably supported relative to the stationary body.

[0007] The motor stator is cylindrical in shape and is fitted and fixed to the outer surface of the housing that constitutes 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 shaft member constituting the rotating body by a cover and a yoke.

[0009] The cover is constructed in the shape of a hollow disc and is fitted and fixed to one axial side of the shaft member. The yoke is constructed in the shape of a cylinder and its axial end is connected and fixed to the radially outer end of the cover. The motor rotor is fitted and fixed to the inner circumferential surface of the yoke.

[0010] The propeller of the aircraft is supported and fixed coaxially with the shaft member at one end of the shaft member on the axial side. [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] In the conventional structure described in Japanese Patent Publication No. 2020-72530, no preload is applied to the balls in each row, so the stationary body and the rotating body rattle in the axial direction by an amount corresponding to the axial internal gap of each row. Therefore, when transporting the aircraft on the back of a vehicle or the like, the rotating body vibrates in the axial direction relative to the stationary body, that is, the motor rotor and propeller supported by the rotating body vibrate, which may cause damage to the motor rotor and propeller.

[0013] 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. In particular, drones and other flying objects used for competition and aerobatic flight have high flight speeds, large changes in flight speed, and / or frequent changes in flight direction. As a result, the moment load acting on the rotating body increases with changes in flight speed and / or flight direction, and the direction of the moment load changes frequently. Therefore, improving the rigidity against this moment load is desirable.

[0014] One way to increase the moment stiffness of a rotating support device for an aircraft is to increase the number of balls in each row or increase the diameter of the balls in each row by increasing the diameter of the balls' pitch circles. In this case, in the rotating support device for an aircraft described in Japanese Patent Publication No. 2020-072530, the pitch circle diameters of the balls in both rows are set to be equal in size, so in order to increase the moment stiffness, it is necessary to increase the pitch circle diameters of the balls in both rows. However, increasing the pitch circle diameters of the balls in both rows tends to increase the weight of the rotating support device for the aircraft, which leads to an increase in power consumption. As a result, the problem of a shorter flight range for the aircraft arises.

[0015] The present disclosure aims to provide a rotary support device and a rotary drive device for an aircraft that can suppress axial rattle between a stationary body and a rotating body, and that can easily ensure moment rigidity while suppressing an increase in weight. [Means for solving the problem]

[0016] A rotating support device for an aircraft according to a first aspect of this disclosure is A stationary body having a double row of outer ring raceways on its inner circumference, which does not rotate when combined with the motor stator during use, A rotating body having double rows of inner ring raceways on its outer circumference, which, when in use, is combined with a propeller positioned axially to one side of the motor rotor and the stationary body, and rotates together with the motor rotor and propeller. Between the double-row outer ring raceway and the double-row inner ring raceway, there are multiple rolling elements arranged in each row.

[0017] Each of the rolling elements in each row is provided with a back-to-back combination type contact angle and preload.

[0018] The pitch circle diameter of the rolling element in one row on the axial side is larger than the pitch circle diameter of the rolling element in the other row on the axial side.

[0019] In the rotating support device for an aircraft according to a second aspect of this disclosure, in the rotating support device for an aircraft according to a first aspect of this disclosure, The stationary body includes a first outer ring on its inner circumferential surface, which has an outer ring raceway on one axial side of the double row of outer ring raceways formed thereon, and a second outer ring on its inner circumferential surface, which has an outer ring raceway on the other axial side of the double row of outer ring raceways formed thereon. The rotating body includes a shaft member on its outer circumferential surface, which has an inner ring raceway on the other axial side of the double row of inner ring raceways formed thereon, and an inner ring on its outer circumferential surface, which has an inner ring raceway on one axial side of the double row of inner ring raceways formed thereon, and which is fitted onto the shaft member.

[0020] A rotating support device for an aircraft according to a third aspect of the present disclosure comprises a spacer and / or elastic member disposed between the first outer ring and the second outer ring, in the same manner as the rotating support device for an aircraft according to a second aspect of the present disclosure.

[0021] In the rotary support device for an aircraft according to the fourth aspect of the present disclosure, in the rotary support device for an aircraft according to the second or third aspect of the present disclosure, the stationary body further includes a housing that internally fits and supports the first outer ring and the second outer ring.

[0022] In the rotary support device for an aircraft according to the fifth aspect of the present disclosure, in the rotary support device for an aircraft according to the fourth aspect of the present disclosure, the outer diameter of the first outer ring is larger than the outer diameter of the second outer ring. Further, the housing has a stepped surface on its inner peripheral surface against which the end surface on the other axial side of the second outer ring abuts.

[0023] The rotary drive device for an aircraft according to the sixth aspect of the present disclosure includes a motor stator, a motor rotor, and a rotary support device for an aircraft, and the rotary support device for an aircraft is constituted by the rotary support device for an aircraft according to any one of the first to fifth aspects of the present disclosure.

[0024] The rotary drive device for an aircraft according to the seventh aspect of the present disclosure includes a motor stator, a motor rotor, and a rotary support device for an aircraft, and the rotary support device for an aircraft is constituted by the rotary support device for an aircraft according to the second or third aspect of the present disclosure. Further, the first outer ring and the second outer ring are internally fitted and supported by the motor stator. The outer diameter of the first outer ring is larger than the outer diameter of the second outer ring. The motor stator has a stepped surface on its inner peripheral surface against which the end surface on the other axial side of the second outer ring abuts.

Advantages of the Invention

[0025] According to the rotary support device for an aircraft and the rotary drive device for an aircraft according to one aspect of the present disclosure, axial play between the stationary body and the rotating body can be suppressed, and moment rigidity can be easily ensured while suppressing an increase in weight.

Brief Description of the Drawings

[0026] [Figure 1] FIG. 1 is a cross-sectional view of a rotary drive device for an aircraft according to a first example of an embodiment of the present disclosure. [Figure 2]Figure 2 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. [Modes for carrying out the invention]

[0027] [Example 1] A first example of an embodiment of the present disclosure will be described with reference to Figure 1.

[0028] The aircraft to which the rotating support device for aircraft of this disclosure can be applied is not limited to drones or other aircraft of any particular type, such as unmanned or manned aircraft, or small or large aircraft.

[0029] The rotating support device 1 for the aircraft constitutes a part of the rotating drive device 2 for the aircraft. That is, the rotating drive device 2 for the aircraft comprises the rotating support device 1 and a drive motor 3 which includes a motor stator 5 and a motor rotor 6.

[0030] 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 Figure 1, and the other axial side refers to the lower side of Figure 1.

[0031] The rotating support device 1 for the aircraft rotatably supports the propeller 4 of the aircraft relative to the aircraft frame.

[0032] The drive motor 3 comprises a motor stator 5 and a motor rotor 6, and generates rotational force to drive the propeller 4. The drive motor 3 can be either a radial gap type, in which the motor stator 5 and motor rotor 6 are opposed radially, or an axial gap type, in which the motor stator and motor rotor are opposed axially. In this example, the drive motor 3 is a radial gap type, and more specifically, an outer rotor type, in which the motor rotor 6 is positioned radially outside the motor stator 5.

[0033] The rotating support device 1 for the aircraft comprises a stationary body 7, a rotating body 8, and a plurality of rolling elements 9a, 9b.

[0034] The stationary body 7 has double rows of outer ring raceways 10a and 10b on its inner circumferential surface and does not rotate when combined with the motor stator 5 during use. The stationary body 7 is supported and fixed to the machine frame directly or via other members. In this example, the stationary body 7 is supported and fixed to the machine frame via the motor stator 5.

[0035] The rotating body 8 has double rows of inner ring raceways 11a and 11b on its outer circumference and, when in use, is combined with a propeller 4 positioned axially to one side of the motor rotor 6 and stationary body 7, and rotates together with the motor rotor 6 and propeller 4.

[0036] Multiple rolling elements 9a and 9b are positioned between the double-row outer ring raceways 10a and 10b and the double-row inner ring raceways 11a and 11b, in each row. As a result, the rotating body 8 is rotatably supported radially inward of the stationary body 7.

[0037] Each row of rolling elements 9a and 9b is provided with a back-to-back combination type (DB type) contact angle and preload.

[0038] Therefore, the rotating support device 1 for aircraft in this example can suppress axial rattle between the stationary body 7 and the rotating body 8. Consequently, when transporting an aircraft, for example, on the back of a vehicle, axial vibration of the rotating body 8 relative to the stationary body 7 can be suppressed, preventing vibration of the motor rotor 6 and propeller 4 supported by the rotating body 8.

[0039] In particular, in the rotating support device 1 for aircraft of this disclosure, the pitch circle diameter PCD1 of the rolling elements 9a in one row on the axial side is larger than the pitch circle diameter PCD2 of the rolling elements 9b in the other row on the axial side (PCD1 > PCD2). Therefore, the rotating support device 1 for aircraft of this disclosure makes it easier to ensure moment rigidity while suppressing an increase in weight.

[0040] In other words, in aircraft such as drones used for competition and aerobatic flying, the flight speed is high, the flight speed changes significantly, and / or the flight direction changes frequently. As a result, the moment load acting on the rotating body 8 increases with changes in flight speed and / or flight direction, and the direction of the moment load changes frequently. For this reason, improvement in the moment rigidity of the rotating support device for aircraft is desirable.

[0041] One way to increase the moment stiffness of the rotating support device 1 for the aircraft is to increase the pitch circle diameters PCD1 and PCD2 of the rolling elements 9a and 9b in both rows. If the pitch circle diameters PCD1 and PCD2 of the rolling elements 9a and 9b in both rows are equal, increasing each of the pitch circle diameters PCD1 and PCD2 in order to increase the moment stiffness will likely increase the weight of the rotating support device 1 for the aircraft, leading to increased power consumption. As a result, the aircraft's flight range will be shortened.

[0042] Here, when the flight speed and / or direction of the aircraft changes during flight, a moment load M acts on the rotating body 8 in a direction that causes it to tilt radially, with the portion of the rotating body 8 supported by the upper row of rolling elements 9a, i.e., the axial portion having an inner ring raceway 11a on its outer circumference, as the pivot point. In order to ensure rigidity against such moment load M, it is effective to increase the pitch circle diameter PCD1 of the upper (one axial side) row of rolling elements 9a that rotatably support the pivot point relative to the stationary body 7.

[0043] In this regard, the present disclosure makes the pitch circle diameter PCD1 of the rolling elements 9a in the upper row (one side in the axial direction) larger than the pitch circle diameter PCD2 of the rolling elements 9b in the lower row (the other side in the axial direction). Therefore, the rotating support device 1 for aircraft of the present disclosure makes it easier to secure moment rigidity while suppressing an increase in weight. Consequently, power consumption can be reduced and the flight range of the aircraft can be extended.

[0044] The stationary body 7 and the rotating body 8 can each employ any structure as long as they can be assembled.

[0045] For example, the stationary body 7 can be composed of a single outer ring with double rows of outer ring raceways 10a and 10b directly formed on its inner surface.

[0046] Alternatively, the stationary body 7 may be configured to include a first outer ring 12 having one axial outer ring raceway 10a of the double-row outer ring raceways 10a and 10b formed on its inner circumferential surface, and a second outer ring 13 having the other axial outer ring raceway 10b of the double-row outer ring raceways 10a and 10b formed on its inner circumferential surface. In this case, optionally and additionally, the stationary body 7 may further include a housing that internally fits and supports the first outer ring 12 and the second outer ring 13. Additionally or alternatively, a spacer 23 and / or elastic member 24 may be placed between the first outer ring 12 and the second outer ring 13.

[0047] The rotating body 8 can be composed of a single shaft member on which double rows of inner ring raceways 11a and 11b are directly formed on its outer circumferential surface.

[0048] Alternatively, the rotating body 8 may be configured to include a shaft member having one of the two rows of inner ring raceways 11a and 11b formed on its outer circumferential surface, and an inner ring having the other of the two rows of inner ring raceways 11a and 11b formed on its outer circumferential surface and fitted onto the shaft member.

[0049] In this example, the stationary body 7 includes a first outer ring 12 on which one of the double-row outer ring raceways 10a and 10b, specifically the outer ring raceway 10a on one axial side, is formed on its inner circumferential surface, and a second outer ring 13 on which the other of the double-row outer ring raceways 10a and 10b, specifically the outer ring raceway 10b, is formed on its inner circumferential surface. In this example, the first outer ring 12 and the second outer ring 13 are spaced apart in the axial direction. Therefore, the distance between the rows of rolling elements 9a and 9b can be increased to ensure the moment rigidity of the rotating support device 1 for the aircraft.

[0050] Each of the outer ring raceways 10a and 10b has a generatrix shape corresponding to the shape of the multiple rolling elements 9a and 9b. When the multiple rolling elements 9a and 9b are composed of balls, each of the outer ring raceways 10a and 10b has an arc-shaped generatrix, and when the multiple rolling elements 9a and 9b are composed of cone-shaped rollers, each of the outer ring raceways 10a and 10b has a linear generatrix inclined with respect to the central axis of the stationary body 7. In this example, the multiple rolling elements 9a and 9b are composed of balls. Therefore, each of the outer ring raceways 10a and 10b has an arc-shaped generatrix. Furthermore, each of the outer ring raceways 10a and 10b may be angular contact or deep groove, provided there are no manufacturing problems such as assembly issues. In this example, each of the outer ring raceways 10a and 10b is angular contact.

[0051] In this example, the diameter (groove bottom diameter) of the outer ring raceway 10a on one axial side is set to be larger than the diameter (groove bottom diameter) of the outer ring raceway 10b on the other axial side.

[0052] Each of the first outer ring 12 and the second outer ring 13 is constructed in a cylindrical shape from a hard metal such as medium carbon steel. The outer ring raceway 10a on one axial side is formed in the axial middle portion of the inner circumferential surface of the first outer ring 12. The outer ring raceway 10b on the other axial side is formed in the axial middle portion of the inner circumferential surface of the second outer ring 13.

[0053] In this example, the outer diameter of the first outer ring 12 is larger than the outer diameter of the second outer ring 13.

[0054] In this example, the first outer ring 12 optionally includes a flange 14 projecting radially outward from one end on the axial side. The flange 14 functions as a stopper to prevent the amount of the first outer ring 12 from entering the other axial side relative to the radially inward side of the motor stator 5 from becoming excessively large. In this example, the outer diameter of the portion of the first outer ring 12 that is axially separated from the flange 14 is also larger than the outer diameter of the second outer ring 13.

[0055] In this example, the rotating body 8 includes a shaft member 15 on which the inner ring raceway 11b on the other axial side of the double row of inner ring raceways 11a and 11b is formed on its outer circumferential surface, and an inner ring 16 on which the inner ring raceway 11a on the one axial side of the double row of inner ring raceways 11a and 11b is formed on its outer circumferential surface and fitted onto the shaft member 15.

[0056] Each of the inner raceways 11a and 11b has a generatrix shape corresponding to the shape of the multiple rolling elements 9a and 9b. When the multiple rolling elements 9a and 9b are composed of balls, each of the inner raceways 11a and 11b has an arc-shaped generatrix, and when the multiple rolling elements 9a and 9b are composed of cone-shaped rollers, each of the inner raceways 11a and 11b has a linear generatrix inclined with respect to the central axis of the rotating body 8. In this example, the multiple rolling elements 9a and 9b are composed of balls. Therefore, each of the inner raceways 11a and 11b has an arc-shaped generatrix. Furthermore, each of the inner raceways 11a and 11b may be angular contact or deep groove, provided there are no manufacturing problems such as assembly issues. In this example, each of the inner raceways 11a and 11b is angular contact.

[0057] In this example, the diameter (groove bottom diameter) of the inner ring raceway 11a on one axial side is set to be larger than the diameter (groove bottom diameter) of the inner ring raceway 11b on the other axial side.

[0058] The shaft member 15 is made of a hard metal such as an iron alloy. In this example, the inner ring raceway 11b on the other axial side is formed on the outer circumferential surface of the other axial end of the shaft member 15.

[0059] The portion of the shaft member 15 that supports the propeller 4 can adopt any structure as long as it can support the propeller 4. For example, the portion of the shaft member 15 located on one axial side of the stationary body 7 can be fitted with an annular portion provided at the radial center of the propeller 4 in a way that prevents relative rotation, or it can be fitted with a shaft portion provided at the radial center of the propeller 4 in a way that allows relative rotation, or it can be equipped with a rotating flange for supporting the propeller 4 on the portion located on one axial side of the stationary body 7.

[0060] In this example, the shaft member 15 has a structure in which an annular portion 21 provided at the radial center of the propeller 4 is fitted onto the portion located axially to one side of the stationary body 7 in a manner that prevents relative rotation. In this example, in addition to the propeller 4, the motor rotor 6 is also supported via a yoke 22, which is configured as a hollow circular plate, on the portion of the shaft member 15 located axially to one side of the stationary body 7 in a manner that prevents relative rotation.

[0061] Specifically, the shaft member 15 has a small-diameter shaft portion 17 at its axial end, which is located on one axial side of the stationary body 7, and has a smaller outer diameter than the portion adjacent to it on the other axial side. The outer circumferential surface of the portion of the shaft member 15 adjacent to the small-diameter shaft portion 17 on the other axial side and the outer circumferential surface of the small-diameter shaft portion 17 are connected by a stepped surface 18 facing one axial side.

[0062] In this example, the propeller 4 and yoke 22 are fitted onto the other axial side of the small-diameter shaft portion 17 in the order of yoke 22 and the annular portion 21 of the propeller 4 from the other axial side, so as to prevent relative rotation. They are also axially clamped between the side surface of the nut 19, which is screwed onto one axial side of the small-diameter shaft portion 17, and the stepped surface 18, thereby connecting and fixing them to the shaft member 15. Various structures can be used to fit the yoke 22 and the annular portion 21 of the propeller 4 onto the other axial side of the small-diameter shaft portion 17 so as to prevent relative rotation, such as non-circular fittings like serration fittings and key engagements, but in this example, serration fittings are used.

[0063] In this example, the shaft member 15 has a hollow structure. That is, the shaft member 15 has a central hole 20 that penetrates the radial center in the axial direction. However, when implementing this disclosure, the shaft member may have a bottomed hole that is open only on one side in the axial direction or the other side in the axial direction, that is, a structure in which part is made up of a hollow structure and the remainder is made up of a solid structure, or it may have a solid structure without a central hole.

[0064] The inner ring 16 is constructed in a cylindrical shape from a hard metal such as an iron alloy. The inner ring raceway 11a on one axial side is formed on the outer circumferential surface of the axial intermediate portion of the inner ring 16.

[0065] The rotating body 8 is constructed by fitting the inner ring 16 onto the axial middle portion of the shaft member 15 and then joining and fixing the shaft member 15 and the inner ring 16 together. In this example, the joining and fixing of the shaft member 15 and the inner ring 16 is performed by press-fitting (tight fit) the inner ring 16 onto the axial middle portion of the shaft member 15, and / or by bonding the shaft member 15 and the inner ring 16 together.

[0066] In implementing this disclosure, a configuration can be adopted in which a fitting shaft portion having a smaller diameter than the portion adjacent to the other axial side is provided in the axial middle portion of the shaft member, and the outer circumferential surface of the fitting shaft portion and the outer circumferential surface of the portion adjacent to the other axial side of the fitting shaft portion are connected by a positioning step surface facing one axial side. In this case, the rotating body can be constructed by fitting the inner ring onto the fitting shaft portion and joining and fixing the shaft member and the inner ring with the other axial end surface of the inner ring in contact with the positioning step surface.

[0067] In any case, in the rotating support device 1 for the aircraft in this example, the rotating body 8 is composed of a shaft member 15 on which an inner ring raceway 11b on the other axial side is formed on its outer circumferential surface, and an inner ring 16 on which an inner ring raceway 11a on one axial side is formed on its outer circumferential surface and is fitted onto the shaft member 15. That is, compared to a conventional structure in which the rotating body is composed of a first inner ring on which an inner ring raceway on one axial side is formed on its outer circumferential surface, a second inner ring on which an inner ring raceway on the other axial side is formed on its outer circumferential surface, and a shaft member on which the first and second inner rings are fitted, the rotating support device 1 for the aircraft has a structure in which the second inner ring is omitted and the inner ring raceway 11b on the other axial side is directly formed on the outer circumferential surface of the shaft member 15.

[0068] In this example of a rotating support device 1 for an aircraft, the second inner ring can be omitted compared to the conventional structure, thereby reducing the cumulative tolerance when combining the components that make up the rotating support device 1 for an aircraft. Consequently, it is easier to ensure coaxiality between the stationary body 7 and the rotating body 8. As a result, it is easier to ensure coaxiality between the motor stator 5 attached to the stationary body 7 and the motor rotor 6 attached to the rotating body 8. Consequently, it becomes easier to manage the radial gap between the motor stator 5 and the motor rotor 6. In addition, it is easier to suppress the rotational runout of the propeller 4 supported by the rotating body 8.

[0069] In the rotating support device 1 for the aircraft in this example, the second inner ring can be omitted compared to the conventional structure, which makes it easier to reduce the radial thickness of the rotating body 8 and thus reduce the weight. In other words, it is easier to achieve a lighter rotating support device 1 for the aircraft.

[0070] The rolling elements 9a and 9b are made of hard metals such as bearing steel, or ceramics. The rolling elements 9a and 9b can also be made of balls or tapered rollers. If the rolling elements 9a and 9b are made of balls, the ball diameters of the rolling elements 9a and 9b in both rows can be the same, or the ball diameter of the rolling element 9a in one axial row can be larger or smaller than the ball diameter of the rolling element 9b in the other axial row.

[0071] In this example, the rolling elements 9a and 9b are composed of balls. Furthermore, the ball diameter of the rolling elements 9a in one axial row is larger than the ball diameter of the rolling elements 9b in the other axial row. The rolling elements 9a and 9b in each row are held rotatably by a retainer (not shown).

[0072] The rotating support device 1 for the aircraft may optionally include a spacer 23 and / or an elastic member 24 positioned between the first outer ring 12 and the second outer ring 13.

[0073] When only a spacer 23 is placed between the first outer ring 12 and the second outer ring 13, the rolling elements 9a and 9b are subjected to a fixed-position preload. In contrast, when only an elastic member 24, or both a spacer 23 and an elastic member 24, are placed between the first outer ring 12 and the second outer ring 13, the rolling elements 9a and 9b are subjected to a constant-pressure preload. In this case, the magnitude of the preload applied to the rolling elements 9a and 9b can be adjusted by adjusting the elasticity of the elastic member 24. Whether to apply a constant-pressure preload or a fixed-position preload to the rolling elements 9a and 9b is appropriately selected according to the performance required of the rotating support device 1 for the aircraft.

[0074] The rotating support device 1 for the aircraft in this example includes a spacer 23 and an elastic member 24, which are positioned between the first outer ring 12 and the second outer ring 13. Specifically, the spacer 23 and the elastic member 24 are positioned between the first outer ring 12 and the second outer ring 13, starting from one axial side.

[0075] The spacer 23 can be configured as a continuous annular shape or as a partial annular shape with a discontinuity at one point in the circumferential direction. In this example, the spacer 23 is configured as a continuous annular shape. The spacer 23 can be made of any material, such as metal or synthetic resin, as long as the required strength and rigidity can be ensured.

[0076] In this example, the spacer 23 has a hollow circular flat side plate portion 25 and a cylindrical tube portion 26 extending from the radially inner end of the side plate portion 25 toward the other axial side. The outer diameter of the side plate portion 25 is approximately the same as the outer diameter of the portion of the first outer ring 12 that is axially separated from the flange portion 14. The outer diameter of the tube portion 26 is smaller than the outer diameter of the second outer ring 13. Also, the inner diameter of the tube portion 26 is larger than the outer diameter of the other axial end face of the inner ring 16. The side plate portion 25 is fitted into the motor stator 5 without radial play, and the axial side surface of the radially outer portion of the side plate portion 25 abuts against the other axial end face of the first outer ring 12.

[0077] The elastic member 24 can be made of a spring such as a coil spring, wave washer, or disc spring, or rubber. In this example, the elastic member 24 is made of a coil spring.

[0078] In this example, the elastic member 24 is elastically sandwiched in the axial direction between the radially inner side of the radially inner portion of the side plate portion 25 of the spacer 23 and the axially end face of the second outer ring 13. As a result, the first outer ring 12 and the second outer ring 13 are elastically pressed apart from each other in the axial direction, and a constant-pressure preload is applied to the rolling elements 9a and 9b. The elastic member 24 is positioned radially by ensuring that the axially oriented portion is positioned without radial play between the outer circumferential surface of the cylindrical portion 26 of the spacer 23 and the inner circumferential surface of the motor stator 5.

[0079] The motor stator 5 includes a core made of a magnetic material having a plurality of teeth, and coils wound around the plurality of teeth, and is configured as a cylinder overall. The inner circumferential surface of the motor stator 5 is formed by the inner circumferential surface of the core.

[0080] In this example, the motor stator 5 is assembled to the stationary body 7 by internally fitting and supporting the outer surfaces of the first outer ring 12 and the second outer ring 13 onto its inner surface.

[0081] The outer circumferential surface of one of the first outer ring 12 and the second outer ring 13 is fitted into the inner circumferential surface of the motor stator 5 without radial play and without displacement away from the other outer ring of the first outer ring 12 and the second outer ring 13. In contrast, the outer circumferential surface of the other outer ring is fitted into the inner circumferential surface of the motor stator 5 without radial play and with axial displacement possible. This allows for constant-pressure preload to be applied to the rolling elements 9a and 9b based on the elasticity of the elastic member 24, and allows the stationary body 7 to be supported and fixed to the machine frame via the motor stator 5. In this example, one of the outer rings is composed of the second outer ring 13, and the other outer ring is composed of the first outer ring 12.

[0082] The motor stator 5 has a stepped surface 30 on its inner circumferential surface against which the other axial end face of the second outer ring 13 abuts. The second outer ring 13 is fitted into the motor stator 5 with its other axial end face abutting against the stepped surface 30. This prevents the second outer ring 13 from being displaced in the other axial direction, away from the first outer ring 12.

[0083] Specifically, in this example, the inner circumferential surface of the motor stator 5 has a stepped cylindrical shape in which its inner diameter gradually increases from the other axial side toward the one axial side. That is, the inner circumferential surface of the motor stator 5 has, in order from the other axial side, a small-diameter stator portion 27, a medium-diameter stator portion 28 which is larger in diameter than the small-diameter stator portion 27, and a large-diameter stator portion 29 which is larger in diameter than the medium-diameter stator portion 28. The stepped surface 30 connects the small-diameter stator portion 27 and the medium-diameter stator portion 28, and is composed of a flat surface perpendicular to the central axis of the motor stator 5 and facing toward one axial side. The medium-diameter stator portion 28 and the large-diameter stator portion 29 are connected by a stepped surface 31 which faces toward one axial side.

[0084] In this example, the second outer ring 13 is positioned axially relative to the motor stator 5 by bringing its other axial end face into contact with the stepped surface 30, and is internally fitted and / or bonded to the other axial end of the stator's middle diameter portion 28. The portion of the first outer ring 12 located axially to the other side of the flange portion 14 is internally fitted to the stator's large diameter portion 29 without radial play and allowing for axial displacement.

[0085] The elastic member 24 is fitted into the stator's middle diameter portion 28 without radial play. The side plate portion 25 of the spacer 23 is fitted into the stator's large diameter portion 29 without radial play. The other axial side of the radially outer portion of the side plate portion 25 is in contact with or in close proximity to the stepped surface 31. The other axial side of the flange portion 14 of the first outer ring 12 is in contact with or in close proximity to one axial side of the core constituting the motor stator 5.

[0086] In the rotary drive system 2 for the aircraft in this example, the motor stator 5 is provided with a stepped surface 30 for abutting against the other axial end face of the second outer ring 13. Therefore, the rotary drive system 2 for the aircraft in this example has a structure in which the first outer ring 12 and the second outer ring 13 are assembled to the motor stator 5 from one axial side each. Thus, assembly can be improved.

[0087] In other words, if the structure requires that the first outer ring and the second outer ring be assembled to the motor stator from one axial side for the first outer ring and from the other axial side for the second outer ring, then it may be necessary to change the orientation of the motor stator when assembling each ring. In contrast, in the structure of this example, the first outer ring 12 and the second outer ring 13 are assembled to the motor stator 5 from one axial side for each ring, so it is not necessary to change the orientation of the motor stator when assembling each ring. This improves ease of assembly.

[0088] In this example, the core is connected and fixed to the aircraft frame. That is, in this example, the stationary body 7 is supported and fixed to the aircraft frame via the core. The structure for connecting and fixing the core to the aircraft frame is not limited. In this example, the core has support holes (not shown) at multiple locations in the circumferential direction, which open only on the other axial side. The stationary body 7 is supported and fixed to the aircraft frame by screwing bolts, which are inserted through holes provided in the aircraft frame, into the support holes of the core, which is fitted and fixed to the stationary body 7, from the other axial side.

[0089] The motor rotor 6 is configured in a cylindrical shape, with south poles and north poles alternately arranged on its inner circumferential surface in the circumferential direction. The motor rotor 6 is positioned around the motor stator 5, coaxially with the motor stator 5, and capable of relative rotation with respect to the motor stator 5.

[0090] In this example, the motor rotor 6 is combined with the yoke 22 by connecting and fixing one end of its axial direction to the radially outer end of the yoke 22, and is supported and fixed to the shaft member 15 via the yoke 22. Alternatively, a yoke having a cylindrical portion extending from the radially outer end toward the other axial direction can be used, and a structure in which the motor rotor 6 is fitted and fixed inside this cylindrical portion can also be adopted.

[0091] In any case, with the motor stator 5, motor rotor 6, and propeller 4 attached to the rotating support device 1 for the aircraft in this example, current is supplied to the coils constituting the motor stator 5, causing the multiple teeth of the motor stator 5 to become magnetized. This generates an electromagnetic force between the multiple teeth and the multiple S poles and N poles of the motor rotor 6, causing the motor rotor 6 to rotate relative to the motor stator 5. As a result, the shaft member 15 and the propeller 4 are driven to rotate.

[0092] [Example 2] A second example of the embodiment of this disclosure will be described with reference to Figure 2.

[0093] In the rotary drive device 2a for the aircraft in this example, the stationary body 7a further includes a housing 32 that internally fits and supports the first outer ring 12 and the second outer ring 13a.

[0094] The housing 32 can employ any structure as long as it has a portion that internally supports the first outer ring 12 and the second outer ring 13a and supports the motor stator 5a. In this example, the housing 32 has a cylindrical main body portion 33 that internally supports the first outer ring 12 and the second outer ring 13a and externally supports the motor stator 5a, and a stationary flange 34 that protrudes radially outward from the other axial end of the main body portion 33.

[0095] In this example, the housing 32 has a stepped surface 38 on its inner circumferential surface against which the other axial end face of the second outer ring 13 abuts. The second outer ring 13 is fitted into the housing 32 with its other axial end face abutting against the stepped surface 38. This prevents the second outer ring 13 from being displaced in the other axial direction, away from the first outer ring 12.

[0096] Specifically, in this example, the inner circumferential surface of the main body portion 33 constituting the housing 32 has a stepped cylindrical surface shape in which its inner diameter gradually increases from the other axial side toward the one axial side. That is, the inner circumferential surface of the main body portion 33 has, in order from the other axial side, a housing small diameter portion 35, a housing medium diameter portion 36 which is larger in diameter than the housing small diameter portion 35, and a housing large diameter portion 37 which is larger in diameter than the housing medium diameter portion 36. The stepped surface 38 connects the housing small diameter portion 35 and the housing medium diameter portion 36, and is composed of a flat surface perpendicular to the central axis of the housing 32 and facing toward one axial side. The housing medium diameter portion 36 and the housing large diameter portion 37 are connected by a stepped surface 39 which faces toward one axial side.

[0097] The second outer ring 13 is positioned axially relative to the main body 33 by bringing its other axial end face into contact with the stepped surface 38, and is then fitted and fixed to the other axial end of the housing's middle diameter portion 36 by press-fitting, bonding, or other means.

[0098] The portion of the first outer ring 12 located on the axial side of the flange portion 14 is fitted into the large-diameter portion 37 of the housing without radial play and allowing for axial displacement.

[0099] The elastic member 24 is fitted into the middle diameter portion 36 of the housing without radial play. The side plate portion 25 of the spacer 23 is fitted into the large diameter portion 37 of the housing without radial play. The other axial side of the radially outer portion of the side plate portion 25 is in contact with or in close proximity to the stepped surface 39. The other axial side of the flange portion 14 of the first outer ring 12 is in contact with or in close proximity to one axial side of the main body portion 33.

[0100] In the rotating support device 1a for the aircraft in this example, the housing 32 is provided with a stepped surface 38 for abutting the other axial end face of the second outer ring 13. Therefore, in the rotating support device 1a for the aircraft in this example, the assembly of the first outer ring 12 and the second outer ring 13 to the housing 32 is performed from one axial side, respectively. Consequently, for the same reasons as in the first example, ease of assembly can be improved.

[0101] In this example, the outer circumferential surface of the main body portion 33 constituting the housing 32 is composed of a cylindrical surface whose outer diameter does not change in the axial direction, except for the end on the other axial side where the stationary flange 34 is located. In this example, the inner circumferential surface of the motor stator 5a is composed of a cylindrical surface whose inner diameter does not change in the axial direction. The inner circumferential surface of the motor stator 5a is externally fitted and fixed to the outer circumferential surface of the main body portion 33 constituting the housing 32 by press-fitting, adhesive, or the like.

[0102] The stationary flange 34 is used to support and fix the stationary body 7a to the aircraft frame. The stationary flange 34 has multiple flange-side support holes 40 that penetrate axially at multiple locations in the circumferential direction in the radially intermediate part. The flange-side support holes 40 are made up of threaded holes.

[0103] The stationary body 7a is supported and fixed to the aircraft frame by inserting a support bolt, which is a connecting member, through a frame-side support hole provided in the aircraft frame and screwing it into the flange-side support hole 40. In addition, when implementing this disclosure, the flange-side support hole 40 can be configured as a through hole, and the stationary body 7a can also be supported and fixed to the aircraft frame by screwing the bolt inserted through the flange-side support hole 40 into a frame-side support hole provided in the aircraft frame.

[0104] The other components and effects of the second example are the same as those of the first example. [Explanation of Symbols]

[0105] 1, 1a Rotating support device for aircraft 2, 2a Rotary drive device for aircraft 3, 3a Drive motor 4 propellers 5. 5a Motor Stator 6 Motor Rotor 7, 7a Stationary body 8. Revolving bodies 9a, 9b rolling elements 10a, 10b Outer ring track 11a, 11b Inner ring track 12. First outer ring 13. Second outer ring 14. Guard section 15 Shaft member 16 Inner circle 17 Small diameter shaft section 18 Step surface 19 nuts 20 center hole 21 Ring section 22 York 23 Spacers 24 Elastic members 25 Side plate part 26 Cylinder part 27 Stator small diameter section 28 Stator middle diameter section 29 Large diameter section of stator 30 Step surface 31 Step surface 32 Housing 33 Main body 34 Stationary flange 35 Small diameter section of housing 36 Housing mid-diameter section 37 Large diameter section of housing 38 Step surface 39 Step surface 40 Flange-side support holes

Claims

1. A stationary body having a double row of outer ring raceways on its inner circumference, which does not rotate when combined with the motor stator during use, A rotating body having double rows of inner ring raceways on its outer circumference, which, when in use, is combined with a propeller positioned axially to one side of the motor rotor and the stationary body, and rotates together with the motor rotor and propeller. The system comprises multiple rolling elements arranged between the double-row outer ring raceway and the double-row inner ring raceway, with each row having multiple rolling elements. Each of the rolling elements in each row is provided with a back-to-back combination type contact angle and preload. The pitch circle diameter of the rolling element in one row on the axial side is larger than the pitch circle diameter of the rolling element in the other row on the axial side. Rotation support device for aircraft.

2. The stationary body includes a first outer ring on its inner circumferential surface, which has an outer ring raceway on one axial side of the double row of outer ring raceways formed thereon, and a second outer ring on its inner circumferential surface, which has an outer ring raceway on the other axial side of the double row of outer ring raceways formed thereon. The rotating body includes a shaft member on its outer circumferential surface, which has an inner ring raceway on the other axial side of the double row of inner ring raceways formed thereon, and an inner ring on its outer circumferential surface, which has an inner ring raceway on the one axial side of the double row of inner ring raceways formed thereon and is fitted onto the shaft member. Rotating support device for an aircraft according to claim 1.

3. The rotating support device for an aircraft according to claim 2, further comprising a spacer and / or an elastic member disposed between the first outer ring and the second outer ring.

4. The rotating support device for an aircraft according to claim 2, wherein the stationary body further includes a housing that internally fits and supports the first outer ring and the second outer ring.

5. The outer diameter of the first outer ring is larger than the outer diameter of the second outer ring. The housing has a stepped surface on its inner circumferential surface against which the other axial end face of the second outer ring abuts. Rotating support device for an aircraft according to claim 4.

6. It comprises a motor stator, a motor rotor, and a rotating support device for the aircraft. The aforementioned rotating support device for the aircraft is configured as the rotating support device for the aircraft according to any one of claims 1 to 5. Rotary drive device for aircraft.

7. It comprises a motor stator, a motor rotor, and a rotating support device for the aircraft. The aforementioned rotating support device for the aircraft is configured as the rotating support device for the aircraft described in claim 2 or 3. The first outer ring and the second outer ring are internally fitted and supported in the motor stator. The outer diameter of the first outer ring is larger than the outer diameter of the second outer ring. The motor stator has a stepped surface on its inner circumferential surface against which the other axial end face of the second outer ring abuts. Rotary drive device for aircraft.

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