JP7582006B2 - Thrust generating device - Google Patents

Description

The present invention relates to a thrust generating device.

For example, Patent Document 1 discloses a technology for electrically varying the pitch, which is the mounting angle of the propeller (rotor blades) relative to the rotating shaft, without using hydraulics. In this technology, the main rotating shaft is made up of a water turbine shaft and a generator shaft, the input shaft is placed at the tip of the generator shaft, and the power from the electric motor, which is the driving source, is transmitted and amplified to the input shaft via a reduction gear and an actuator.

JP 2010-138912 A

An electric motor may be mounted on a flying object to generate thrust for the flying object. In this case, it is preferable to reduce the weight of the electric motor in order to improve the thrust of the flying object, but Patent Document 1 does not disclose anything about reducing the weight of the electric motor.
Therefore, an object of the present invention is to provide a thrust generating device that can receive the thrust of a rotor while reducing the weight of a motor that generates the thrust.

In order to solve the above problem, a thrust generating device according to one aspect of the present invention includes a first motor that generates a thrust for a rotor, a second motor that generates a rotational motion that changes the pitch angle of the rotor, a first conversion unit that converts the rotational motion of the second motor into linear motion, and a second conversion unit that converts the linear motion converted by the first conversion unit into rotational motion, the first motor includes a rotor, a stator, a stator case that can accommodate the stator in a position facing the rotor, and a bearing that rotatably supports the rotor shaft of the rotor, the stator case includes a first load receiving part that receives an axial load applied to the bearing, and the first load receiving part has a load capacity that differs depending on the direction of the axial load.

As a result, when the axial load on the bearing is received by the stator case, the load capacity can be increased in the direction where the axial load is large and decreased in the direction where the axial load is small. This makes it possible to increase the strength of the first load receiving portion in the direction where the axial load is large and decrease the strength of the first load receiving portion in the direction where the axial load is small, allowing the first motor that generates the thrust to be lighter while receiving the thrust of the rotor.

Furthermore, according to a thrust generating device according to one aspect of the present invention, the first load receiving portion has a load resistance only against a unidirectional axial load.

As a result, when the axial load on the bearing is received by the stator case, the stator case can withstand the load only in the direction in which the axial load is applied, and the structure for withstanding the load in directions in which the axial load is not applied can be omitted. This allows the stator case to be lighter than when the stator case is provided with load resistance against axial loads in both directions, and allows the first motor, which generates the thrust while receiving the thrust of the rotor, to be lighter.

Furthermore, according to a thrust generating device according to one aspect of the present invention, the first load receiving portion has a first step provided on the stator case, and the first step is capable of contacting the axial end face of the outer ring of the bearing.

This allows the rotor shaft to be rotatably supported via the bearing, while the axial load on the outer ring of the bearing can be received by the first step. This makes it possible to receive the thrust of the rotor blades while preventing the stator case from becoming too complicated in configuration, and allows the first motor that generates the thrust to be made lighter.

In addition, according to a thrust generating device according to one aspect of the present invention, the first step is provided only on the axial end face of the outer ring of the bearing, on the side of the mounting surface of the flying object.

This allows the first step to receive the axial load on the axial end face of the outer ring of the bearing on the side where the flying object is attached, and eliminates the need to provide a step on the other side of the axial end face of the outer ring of the bearing, allowing the stator case to be made thinner. This allows the first motor, which generates the thrust, to be made lighter while receiving the thrust of the rotor.

In addition, according to one aspect of the present invention, a thrust generating device includes a plate that is provided on the axial end face of the outer ring of the bearing opposite the mounting surface of the flying object and that can be attached to the stator case.

This makes it possible to position the bearing while preventing the first motor from becoming too heavy, even if the first step is provided only on the axial end face of the outer ring of the bearing on the side where the flying object is attached.

In addition, according to a thrust generating device according to one aspect of the present invention, the stator case includes an inner diameter portion that supports the rotor shaft via the bearing, and a frame that is provided radially outside the inner diameter portion and supports the stator at a position facing the rotor.

This allows the stator and rotor to be positioned opposite each other while supporting the rotor shaft for free rotation, even when the rotor is located radially outward of the rotor shaft.

In addition, according to a thrust generating device according to one aspect of the present invention, the rotor shaft has a second load receiving portion that receives the axial load applied to the bearing, and the second load receiving portion has a different load resistance depending on the direction of the axial load.

As a result, when the axial load on the bearing is received by the rotor shaft, the load capacity can be increased in the direction where the axial load is large and decreased in the direction where the axial load is small. This makes it possible to increase the strength of the second load receiving portion in the direction where the axial load is large and decrease the strength of the second load receiving portion in the direction where the axial load is small, allowing the first motor that generates the thrust to be reduced in weight while receiving the thrust of the rotor.

Furthermore, according to a thrust generating device according to one aspect of the present invention, the second load receiving portion has a load resistance only against a unidirectional axial load.

As a result, when the axial load on the bearing is received by the rotor shaft, the bearing can withstand the load only in the direction in which the axial load is applied, and the structure for withstanding the load in directions in which the axial load is not applied can be omitted. This allows the stator case to be lighter than when the stator case is provided with load resistance against axial loads in both directions, and allows the first motor, which generates the thrust while receiving the thrust of the rotor blades, to be lighter.

In addition, according to a thrust generating device according to one aspect of the present invention, the second load receiving portion has a second step provided on the rotor shaft, and the second step is capable of contacting the axial end face of the inner ring of the bearing.

This allows the rotor shaft to be supported rotatably via the bearing, while the axial load acting on the inner ring of the bearing can be received by the second step. This makes it possible to receive the thrust of the rotor blades while preventing the stator case from becoming too complicated in configuration, and allows the first motor that generates the thrust to be made lighter.

In addition, according to a thrust generating device according to one aspect of the present invention, the second step is provided only on the axial end face of the inner ring of the bearing opposite the mounting surface of the flying object.

This allows the second step to receive the axial load on the axial end face of the inner ring of the bearing opposite the mounting surface of the flying object, and eliminates the need to provide a step on the other side of the axial end face of the inner ring of the bearing, allowing the rotor shaft to be made thinner. This allows the first motor that generates the thrust to be lighter while receiving the thrust of the rotor blades.

In addition, according to one aspect of the present invention, a thrust generating device includes a snap ring that is provided on the axial end face of the inner ring of the bearing on the side of the mounting surface of the flying object and can be attached to the rotor shaft.

This makes it possible to position the bearing while preventing the first motor from becoming too heavy, even if the second step is provided only on the axial end face of the inner ring of the bearing opposite the mounting surface of the flying object.

According to one aspect of the present invention, it is possible to reduce the weight of the motor that generates the thrust while receiving the thrust of the rotor.

FIG. 1( a ) is a perspective view showing a state in which rotors are attached to the thrust generating device according to the first embodiment, and FIGS. 1( b ) and 1 ( c ) are side views showing states in which the pitch angle of the rotors attached to the thrust generating device according to the first embodiment is changed. FIG. 2 is an exploded perspective view showing the configuration of the thrust generating device of FIG. 1(a) as viewed from one end side of the rotating shaft. FIG. 3 is an exploded perspective view showing the configuration of the thrust generating device shown in FIG. 1(a) as viewed from the other end side of the rotating shaft. 4A is a perspective view showing the structure of the thrust generating device shown in FIG. 2 after assembly, and FIG. 4B is a perspective view showing the structure of the thrust generating device shown in FIG. 3 after assembly. FIG. 5(a) is a plan view showing the configuration of the thrust generating device according to the first embodiment, and FIG. 5(b) is a cross-sectional view taken along line AA in FIG. 5(a). FIG. 6(a) is a plan view showing the configuration of the thrust generating device according to the first embodiment, and FIG. 6(b) is a cross-sectional view taken along line BB in FIG. 6(a). FIG. 7(a) is a plan view showing the configuration of a thrust generating motor of the thrust generating device according to the first embodiment, and FIG. 7(b) is a cross-sectional view taken along line CC of FIG. 7(a). 8(a) is a perspective view showing the configuration of the pitch variable motor, vertical transmission unit, and rotary-linear motion conversion unit in FIG. 6, and FIG. 8(b) is a perspective view showing the configuration with the pitch variable motor, vertical transmission unit, and linear motion guide unit in FIG. 8(a) removed. FIG. 9 is an exploded perspective view showing the configuration of the hub in FIG. FIG. 10 is a top view showing the positional relationship between the linear motion body to which the rack is attached and the pinion. FIG. 11(a) is a perspective view showing the position of a linear body corresponding to the pitch angle of the rotor in FIG. 1(b), and FIG. 11(b) is a perspective view showing the position of a linear body corresponding to the pitch angle of the rotor in FIG. 1(c). FIG. 12 is an enlarged cross-sectional view of the portion EA in FIG. FIG. 13 is an exploded perspective view showing the configuration of the thrust generating motor in FIG. 1(a) when viewed obliquely from above. FIG. 14 is an exploded perspective view showing the configuration of the thrust generating motor in FIG. 1(a) when viewed obliquely from below. FIG. 15( a ) is a perspective view showing a state in which rotors are attached to the thrust generating device according to the second embodiment, and FIGS. 15 ( b ) and 15 ( c ) are side views showing states in which the pitch angle of the rotors attached to the thrust generating device according to the second embodiment is changed. FIG. 16 is an exploded perspective view showing the configuration of the thrust generating device of FIG. 15(a) as viewed from one end side of the rotating shaft. FIG. 17 is an exploded perspective view showing the configuration of the thrust generating device shown in FIG. 15(a) as viewed from the other end side of the rotating shaft. 18(a) is a perspective view showing the structure of the thrust generating device shown in FIG. 16 after assembly, and FIG. 18(b) is a perspective view showing the structure of the thrust generating device shown in FIG. 17 after assembly. FIG. 19(a) is a plan view showing the configuration of a thrust generating device according to a second embodiment, and FIG. 19(b) is a cross-sectional view taken along line AA in FIG. 19(a). FIG. 20(a) is a plan view showing the configuration of a thrust generating device according to the second embodiment, and FIG. 20(b) is a cross-sectional view taken along line BB in FIG. 20(a). FIG. 21 is an exploded perspective view showing the configuration of the hub and the extension in FIG. 15(b). FIG. 22 is an exploded perspective view showing the configuration of the mounting portion, the case, and the extension in FIG. 15(b). FIG. 23 is a bottom view showing the configuration of the case in FIG.

Below, the embodiments of the present invention will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the present invention, and not all of the combinations of features described in the embodiments are necessarily essential to the configuration of the present invention. The configuration of the embodiments may be modified or changed as appropriate depending on the specifications of the device to which the present invention is applied and various conditions (conditions of use, environment of use, etc.). The technical scope of the present invention is determined by the claims, and is not limited by the individual embodiments below. Also, the drawings used in the following description may differ in scale and shape from the actual structure in order to make each configuration easier to understand.

In the following explanation, an example will be taken of a rotor having three blades driven by a thrust generating device; however, the number of blades driven by a thrust generating device is not necessarily limited to three and may be N (N is an integer greater than or equal to 2).
FIG. 1(a) is a perspective view showing a state in which a rotor is attached to the thrust generating device according to the first embodiment, FIGS. 1(b) and 1(c) are side views showing a state in which the pitch angle of the rotor attached to the thrust generating device according to the first embodiment is changed, FIGS. 2 and 3 are perspective views showing an exploded configuration of the thrust generating device of FIG. 1(a), and FIGS. 4(a) and 4(b) are perspective views showing the configuration of the thrust generating device of FIGS. 2 and 3 after assembly.

In Fig. 1(a), Fig. 1(b) and Fig. 1(c), the thrust generating device 1 drives the rotors H1 to H3 electrically. The rotors H1 to H3 are attached to the thrust generating device 1 via the grips P1 to P3, respectively. The grips P1 to P3 support the rotors H1 to H3 so that they extend horizontally radially from the thrust generating device 1. The thrust generating device 1 is attached to the flying object HSB via the attachment surface 1A. The flying object HSB to which the thrust generating device 1 is attached is, for example, a flying object or vehicle body such as a multicopter, airplane, rotorcraft, or automobile with flying function that flies with a motor. As shown in Fig. 1(b) and Fig. 1(c), the type in which the rotors H1 to H3 are attached to the bottom of the flying object HSB is called a pusher type. In the pusher type, the flying object HSB flies while being pushed up from below by the thrust generating device 1.

As shown in Figures 1(a), 1(b), 1(c), 2, 3, 4(a) and 4(b), the thrust generating device 1 includes a thrust generating motor (first motor) 2, a pitch variable motor (second motor) 5, a rotation transmission section 6, a rotary-linear converter (first converter) 7, a linear-rotary converter (second converter) 8, an extension 9 and a hub 10. The thrust generating motor 2 includes a stator 2A, a rotor 2B, an outer frame 2C, an inner diameter section 2D and an inner frame 2E. The rotor 2B includes a rotor shaft 4 and hollow sections 3A and 3B on the inner diameter side. The axial end of the rotor shaft 4 is provided with a mounting section 4A for mounting the hub 10 via the extension 9.

The inner frame 2E is located radially outward of the inner diameter portion 2D, and the outer frame 2C is located radially outward of the inner frame 2E. The inner diameter portion 2D is fixed to the outer frame 2C. The inner frame 2E is fixed to the rotor shaft 4 and rotates together with the rotor shaft 4. The rotor shaft 4 is housed in the inner diameter portion 2D. At this time, the mounting portion 4A is located axially outward of the inner diameter portion 2D. The rotor 2B is located along the outer peripheral surface of the inner frame 2E. The stator 2A is located along the inner peripheral surface of the outer frame 2C. At this time, the rotor shaft 4, inner diameter portion 2D, inner frame 2E, rotor 2B, stator 2A, and outer frame 2C are concentrically arranged radially outward from the rotation axis S0.

The thrust generating motor 2 rotates the rotors H1 to H3 around the rotation axis S0 in FIG. 1(b), generating a thrust F from the rotors H1 to H3. The stator 2A is made of electromagnetic steel and windings, and is located on the outside of the rotor 2B. The stator 2A, inner diameter portion 2D, and mounting surface 1A are fixed to the outer frame 2C. At this time, the mounting surface 1A can be fixed to the outer frame 2C via the support portion 1C. The inner diameter portion 2D can be fixed to the back side of the mounting surface 1A via the spacer 2F. The spacer 2F can ensure a space for accommodating the rotation transmission portion 6 within the thrust generating motor 2.

The mounting surface 1A has an opening 1B through which the rotation transmission part 6 can be inserted into the outer frame 2C. The support part 1C extends radially from the mounting surface 1A toward the outer frame 2C. The inner diameter part 2D is cylindrical and rotatably supports the rotor shaft 4 via the bearing U1. The inner frame 2E is annular and supports the rotor 2B. The outer frame 2C is annular and supports the stator 2A.

The mounting surface 1A, outer frame 2C, inner diameter portion 2D, inner frame 2E, spacer 2F, and support portion 1C can be formed, for example, from an alloy such as duralumin. The mounting surface 1A, outer frame 2C, inner diameter portion 2D, inner frame 2E, spacer 2F, and support portion 1C can be integrally formed, for example, by a method such as casting, forging, or cutting.

The rotor 2B is composed of magnets and the like, and is located outside the rotor shaft 4. The rotor 2B and the rotor shaft 4 are fixed to the inner frame 2E. At this time, the rotor shaft 4 can be fixed to the inner frame 2E via the support 2G. The support 2G extends radially from the rotor shaft 4 toward the inner frame 2E. The rotor shaft 4 rotates around the axis of the rotation axis S0 via the bearing U1. As the rotor shaft 4 rotates, the rotor 2B and the inner frame 2E also rotate around the axis of the rotation axis S0. The rotor shaft 4, the mounting part 4A, the inner frame 2E, and the support 2G can be made of an alloy such as duralumin. The rotor shaft 4, the mounting part 4A, the inner frame 2E, and the support 2G can be integrally formed by a method such as casting, forging, or cutting.

The hollow portions 3A and 3B are located inside the thrust generating motor 2. The hollow portion 3A is located between the rotor 2B and the rotor shaft 4 along the circumferential direction of the rotor 2B. The hollow portion 3B is located on the inner diameter side of the rotor shaft 4 along the axial direction of the rotor shaft 4.

The pitch variable motor 5 generates a rotational motion that changes the pitch angles θ1 to θ3 of the rotors H1 to H3. The pitch variable motor 5 is fixed to the inner diameter portion 2D. At least a portion of the pitch variable motor 5 is housed within the thrust generating motor 2. In this case, the pitch variable motor 5 can be located in the hollow portion 3A. The rotation axis of the pitch variable motor 5 can be located parallel to the rotation axis S0 of the thrust generating motor 2.

The rotation transmission unit 6 transmits the rotational motion generated by the pitch variable motor 5 in a direction perpendicular to the rotation axis S0 of the thrust generating motor 2. In other words, the rotation axis of the pitch variable motor 5 and the rotation axis S0 of the thrust generating motor 2 are different parallel axes, and the rotation transmission unit 6 transmits the rotational motion generated by the pitch variable motor 5 onto the axis of the rotation axis S0 of the thrust generating motor 2. The rotation transmission unit 6 is fixed to the inner diameter portion 2D. At least a portion of the rotation transmission unit 6 is housed within the thrust generating motor 2.

The rotary-linear motion conversion unit 7 converts the rotational motion generated by the pitch variable motor 5 and transmitted via the rotation transmission unit 6 into linear motion LM in the axial direction of the rotation axis S0. At least a portion of the rotary-linear motion conversion unit 7 is housed within the thrust generating motor 2. At this time, at least a portion of the rotary-linear motion conversion unit 7 can be located within the hollow portion 3B. In this case, at least a portion of the rotary-linear motion conversion unit 7 can protrude from the hollow portion 3B toward the rotors H1-H3 along the axial direction of the rotation axis S0. The rotary-linear motion conversion unit 7 is fixed to the inner diameter portion 2D.

The linear motion/rotation conversion unit 8 converts the linear motion LM converted by the rotation/linear motion conversion unit 7 into rotational motion around each of the support shafts M1 to M3. The linear motion/rotation conversion unit 8 is located outside the thrust generating motor 2.

The extension 9 is a spacer that maintains a gap between the thrust generating motor 2 and the rotor blades H1 to H3 in the axial direction of the rotation shaft S0. The extension 9 prevents the rotor blades H1 to H3 from colliding with the thrust generating motor 2. The extension 9 is fixed to the rotor shaft 4 via the mounting portion 4A and rotates together with the rotor shaft 4.

The hub 10 houses the linear motion rotation conversion unit 8 and supports the grips P1 to P3 with the grips P1 to P3 protruding from the hub 10. The hub 10 is fixed to the rotor shaft 4 via the extension 9. In other words, the hub 10 is supported by the outer frame 2C in a state in which it can rotate around the axis of the rotation shaft S0 via the rotor shaft 4. The hub 10 supports the rotor blades H1 to H3 in a direction perpendicular to the axial direction of the rotation shaft S0 via the grips P1 to P3.

When the thrust generating motor 2 operates, the rotor 2B rotates about the rotation axis S0, causing the rotors H1 to H3 to rotate. Then, thrust F is generated by the rotors H1 to H3 in accordance with the rotations R1 to R3 of each of the rotors H1 to H3.

Here, the pitch variable motor 5, the rotation transmission unit 6, and the rotary-to-linear conversion unit 7 are fixed to the outer frame 2C. Therefore, even if the rotor 2B rotates, the pitch variable motor 5, the rotation transmission unit 6, and the rotary-to-linear conversion unit 7 do not rotate around the rotation axis S0.

When the pitch variable motor 5 operates, each rotor H1-H3 rotates around the axis of each support shaft M1-M3, and the pitch angles θ1-θ3 of the rotor H1-H3 change. At this time, the rotational motion of the pitch variable motor 5 is transmitted to the rotary-linear converter 7 via the rotation transmission unit 6. The rotational motion of the pitch variable motor 5 is then converted by the rotary-linear converter 7 into linear motion LM in the axial direction of the rotation shaft S0. The single linear motion LM converted by the rotary-linear converter 7 is then converted by the linear-rotation converter 8 into three rotational motions around the axes of the support shafts M1-M3. The rotational motion of each support shaft M1-M3 is then transmitted to each rotor H1-H3 via the grips P1-P3, respectively, and the pitch angles θ1-θ3 of each rotor H1-H3 change.

The thrust generating device 1 can change the thrust by varying the pitch angles θ1 to θ3 of the rotors H1 to H3. Furthermore, by varying the pitch angles θ1 to θ3, the thrust generating device 1 can increase the response speed to thrust changes and improve the stability of the flying object, and can ensure the thrust required for the flying object without increasing the blade length (the length of the rotors H1 to H3), thereby preventing the thrust generating device 1 from becoming larger and heavier. Furthermore, compared to a fixed pitch, the thrust required in each situation can be generated at a lower rotation speed of the thrust generating motor 2, so noise that depends on the rotation speed can be suppressed.

In addition, the thrust generating device 1 does not require hydraulics because the pitch angles θ1 to θ3 of the rotors H1 to H3 are electrically variable. This eliminates the need to provide a hydraulic control unit that controls the supply and discharge of oil, and a complex rotary seal mechanism for oil sealing the rotor, making it possible to prevent the thrust generating device 1 from becoming too large and improving the maintainability of the thrust generating device 1.

In addition, the linear motion conversion unit 8 converts the single linear motion LM converted by the rotary-linear motion conversion unit 7 into three rotational motions around the axes of the support shafts M1 to M3, making it possible to adjust the pitch angles θ1 to θ3 of the three rotors H1 to H3 based on the single linear motion LM converted by the rotary-linear motion conversion unit 7, thereby preventing the thrust generating device 1 from becoming too large.

Furthermore, by housing at least a portion of the rotary-to-linear conversion unit 7 within the thrust generating motor 2, the amount of protrusion of the rotary-to-linear conversion unit 7 from the thrust generating motor 2 in the axial direction of the rotation axis S0 can be reduced. Therefore, even when the thrust generating motor 2 generates the thrust of the rotors H1 to H3 and the pitch angles θ1 to θ3 of the rotors H1 to H3 are varied by the pitch varying motor 5, it is possible to make the thrust generating device 1 more compact in the axial direction of the rotation axis S0.

Furthermore, by accommodating at least a portion of the rotary-linear motion conversion unit 7 within the hollow portion 3B, it is possible to accommodate at least a portion of the rotary-linear motion conversion unit 7 within the thrust generating motor 2 without increasing the size of the thrust generating motor 2 in the axial direction of the rotation axis S0, thereby making it possible to make the thrust generating device 1 compact in the axial direction of the rotation axis S0.

Furthermore, by transmitting the rotational motion generated by the pitch variable motor 5 via the rotation transmission unit 6, it becomes possible to arrange the rotation axis S0 of the thrust generating motor 2 and the rotation axis of the pitch variable motor 5 in parallel, making it possible to house the pitch variable motor 5 within the thrust generating motor 2.

Furthermore, by housing the linear motion rotation conversion unit 8 within the hub 10, it is possible to make the thrust generating device 1 more compact in the axial direction of the rotation axis S0, and to prevent the linear motion rotation conversion unit 8 from being exposed to the outside.

When the rotor blades H1 to H3 rotate around the axis of the rotor shaft 4, centrifugal forces F1 to F3 are respectively applied to the rotor blades H1 to H3. The centrifugal forces F1 to F3 applied to the rotor blades H1 to H3 are transmitted to the support shafts M1 to M3 via the grips P1 to P3, respectively. At this time, the support shafts M1 to M3 automatically adjust the rotation axis of each of the support shafts M1 to M3 based on the centrifugal forces F1 to F3 transmitted to each of the support shafts M1 to M3, thereby improving the rotation accuracy around the axis of each of the support shafts M1 to M3.

The configurations and operations of the rotation transmission unit 6, the rotation-to-linear motion conversion unit 7, and the linear motion-to-rotation conversion unit 8 will be described in more detail below.
Figures 5(a) and 6(a) are plan views showing the configuration of the thrust generating device of the first embodiment, Figure 5(b) is a cross-sectional view taken along line A-A in Figure 5(a), Figure 6(b) is a cross-sectional view taken along line B-B in Figure 6(a), Figure 7(a) is a plan view showing the configuration of a thrust generating motor of the thrust generating device of the first embodiment, and Figure 7(b) is a cross-sectional view taken along line C-C in Figure 7(a).

In Figures 7(a) and 7(b), the rotor 2B is supported by the outer frame 2C via a bearing U1 in a state in which it can rotate around the rotation axis S0. In addition, in the thrust generating motor 2, a hollow portion 3A is provided between the rotor 2B and the rotor shaft 4, and a hollow portion 3B is provided within the rotor shaft 4.

In addition, in Figures 2, 3, 5(a), 5(b), 6(a) and 6(b), the rotation transmission unit 6 includes gears G1 to G3 and support members BJ1 to BJ3. Gears G1 to G3 transmit the rotational motion of the pitch variable motor 5 to the rotary-linear motion conversion unit 7. Gear G1 is attached to one end of the ball screw shaft 7F. Gear G3 is attached to the rotation shaft of the pitch variable motor 5. Gear G2 is provided between gears G1 and G3 in a position where it meshes with gears G1 and G3.

The inner diameter portion 2D supports the gear G1 and the rotary-linear converter 7 via the support member BJ1 in a state in which the gear G1 and the ball screw shaft 7F can rotate. The inner diameter portion 2D also supports the gear G3 and the rotating shaft of the pitch variable motor 5 in a state in which they can rotate via the support member BJ3. The inner diameter portion 2D also supports the gear G2 in a state in which they can rotate via the support members BJ1 and BJ2. At this time, the gear G2 is sandwiched between the support members BJ1 and BJ2 and is positioned in a position in which it meshes with the gears G1 and G3. The gears G1 to G3 are made of a material such as carbon steel, and the support members BJ1 to BJ3 are made of a material such as an aluminum alloy. Note that a belt may be used instead of gears as the mechanism for the rotation transmission portion.

A ball screw can be used as the rotary-linear motion conversion mechanism of the rotary-linear motion conversion unit 7. A sliding screw can also be used as the rotary-linear motion conversion mechanism of the rotary-linear motion conversion unit 7. The rotary-linear motion conversion unit 7 includes a linear motion transmission shaft 7D, a linear motion guide unit 7E, a ball screw shaft 7F, and a ball screw nut 7G.

The linear guide portion 7E guides the ball screw nut 7G and the linear transmission shaft 7D in a direction of linear motion along the rotation axis S0. At this time, the linear guide portion 7E restricts the ball screw nut 7G from rotating in accordance with the rotation of the ball screw shaft 7F. The linear guide portion 7E is shaped to protrude from the support member BJ1. The linear guide portion 7E can be provided integrally with the support member BJ1.

The ball screw shaft 7F is rotatably supported by the support member BJ1 via a bearing U2. The ball screw shaft 7F rotates together with the gear G1 while being screwed into the ball screw nut 7G via rolling elements, and causes the ball screw nut 7G to move linearly.
The ball screw nut 7G moves linearly in accordance with the rotational motion of the ball screw shaft 7F, and transmits the linear motion LM to the linear motion transmission shaft 7D.

The linear motion transmission shaft 7D transmits the linear motion LM of the ball screw nut 7G to the linear motion rotation conversion unit 8. The linear motion transmission shaft 7D is fixed to the ball screw nut 7G, and the tip of the linear motion transmission shaft 7D is inserted into the inner ring of the bearing U3. The linear motion transmission shaft 7D is shaped to include the ball screw nut 7G and a part of the ball screw shaft 7F.

A rack and pinion can be used as the linear motion rotation conversion mechanism of the linear motion rotation conversion unit 8. The linear motion rotation conversion unit 8 includes a linear body 11, racks A1 to A3, a case 21, support shafts M1 to M3, bearings E1 to E3, adapters D1 to D3, and pinions B1 to B3.

The linear body 11 is supported via bearing U3 in a state in which it can rotate around the axis of the linear motion transmission shaft 7D. At this time, the linear body 11 can move linearly along the axial direction of the rotation axis S0 together with the linear motion transmission shaft 7D.

The racks A1 to A3 are supported by a linear moving body 11. Each rack A1 to A3 moves linearly together with the linear moving body 11 while meshing with the pinions B1 to B3, respectively, and rotates the pinions B1 to B3, respectively.

Each of the support shafts M1 to M3 supports the grips P1 to P3 so as to protrude radially in the horizontal direction from the thrust generating device 1. Each of the support shafts M1 to M3 is held in the case 21 in a state in which it can rotate around the axis of each of the support shafts M1 to M3 via the bearings E1 to E3, respectively. The grip P1 and the support shaft M1 can be provided integrally, the grip P2 and the support shaft M2 can be provided integrally, and the grip P3 and the support shaft M3 can be provided integrally. The material of the grips P1 to P3 and the support shafts M1 to M3 is, for example, duralumin. To increase the durability of the grips P1 to P3 and the support shafts M1 to M3, the material of the grips P1 to P3 and the support shafts M1 to M3 may be, for example, titanium.

Each of the pinions B1 to B3 is fixed to a corresponding one of the support shafts M1 to M3. Each of the pinions B1 to B3 rotates in accordance with the linear motion LM of each of the racks A1 to A3, and transmits the rotational motion to each of the support shafts M1 to M3. The material of the pinions B1 to B3 and the racks A1 to A3 is, for example, chrome molybdenum steel.

The case 21 can be used as a part of the hub 10. The case 21 is, for example, a non-split case without a joint surface. The non-split case can be produced by cutting out an ingot. In this case, the non-split case can be produced without joining individual pieces with adhesive or welding. The non-split case may be a seamless case without joints. The case 21 houses the linear body 11, racks A1 to A3, support shafts M1 to M3, bearings E1 to E3, adapters D1 to D3, and pinions B1 to B3. In this case, the case 21 can house the support shafts M1 to M3 at intervals of 120° in the circumferential direction of the rotor shaft 4. The case 21 is fixed to the end surface of the rotor 2B via the extension 9. In addition, the case 21 can support each of the support shafts M1 to M3 against the centrifugal forces F1 to F3 acting on each of the rotor blades H1 to H3 during rotation around the axis of the rotation shaft S0. The case 21 can be formed as a single unit, for example, by cutting duralumin or other materials.

Each of the adapters D1 to D3 is provided between the support shafts M1 to M3 and the bearings E1 to E3, and is supported by the support shafts M1 to M3. The inner circumferential surface of each of the adapters D1 to D3 is formed to fit along the outer circumferential surface of the support shafts M1 to M3, and the outer circumferential surface of each of the adapters D1 to D3 is formed to fit along the inner circumferential surface of the bearings E1 to E3. This allows each of the adapters D1 to D3 to support each of the support shafts M1 to M3 on the inner circumferential side of each of the bearings E1 to E3 while adapting to changes in the diameter of each of the support shafts M1 to M3. The material of the adapters D1 to D3 is, for example, duralumin.

Each of the bearings U3, E1 to E3 can be, for example, a double-row angular ball bearing. A double-row angular ball bearing can be a back-to-back combination of single-row angular ball bearings with an integrated outer ring, or a face-to-face combination of single-row angular ball bearings with an integrated inner ring. A double-row angular ball bearing can withstand radial loads and axial loads in both directions (also known as thrust loads), and a back-to-back combination can also withstand moment loads.

The extension 9 includes a flange 9A. The flange 9A can be provided integrally with the extension 9. The extension 9 can be attached to the end face of the rotor shaft 4 via the flange 9A. Here, the extension 9 can be fixed to the rotor shaft 4 by screwing the flange 9A to the rotor shaft 4 with a bolt J6. The material of the extension 9 and the flange 9A is, for example, duralumin.

The flange 9A has a through hole 9K that penetrates the flange 9A in the axial direction of the rotor shaft 4. A bolt J6 can be inserted into the through hole 9K. The mounting portion 4A has a female thread 4B into which the bolt J6 can be screwed. The female thread 4B is located on the mounting surface side of the flange 9A. The through hole 9K and the female thread 4B can be positioned to correspond to the insertion position of the bolt J6. Here, the extension 9 can be fixed to the rotor shaft 4 by screwing the bolt J6 into the female thread 4B through the through hole 9K and screwing the flange 9A to the mounting portion 4A with the bolt J6.

When the pitch variable motor 5 rotates, the gears G1 to G3 rotate in conjunction with the rotational motion of the pitch variable motor 5. The ball screw shaft 7F rotates in conjunction with the rotational motion of the gear G1, and the linear transmission shaft 7D moves linearly together with the ball screw nut 7G in conjunction with the rotational motion of the ball screw shaft 7F. At this time, the motion of the ball screw nut 7G and the linear transmission shaft 7D is guided by the linear guide section 7E, and is limited to linear motion along the axial direction of the rotation axis S0 within the thrust generating device 1.

The linear motion LM of the linear transmission shaft 7D is transmitted to the linear body 11, and the racks A1 to A3 move linearly together with the linear body 11 in accordance with the linear motion LM of the linear transmission shaft 7D. At this time, the racks A1 to A3 move linearly while meshing with the pinions B1 to B3, respectively, and rotate the pinions B1 to B3. As the pinions B1 to B3 rotate, the support shafts M1 to M3 rotate around their respective axes. The rotational motion of the support shafts M1 to M3 is then transmitted to the rotors H1 to H3 via the grips P1 to P3, respectively, and the pitch angles θ1 to θ3 of the rotors H1 to H3 are changed.

Here, by using a ball screw as the rotary-linear motion conversion mechanism of the rotary-linear motion conversion unit 7, the driving torque required for pitch variation can be reduced compared to when a sliding screw is used, and power consumption of the pitch variation motor 5 can be reduced.
In addition, by providing a linear motion transmission shaft 7D in the rotary-linear motion conversion unit 7, the ball screw and the linear motion body 11 can be arranged at a distance in the axial direction of the rotation axis S0, and the ball screw can be accommodated in the thrust generating motor 2 while the linear motion body 11 can be accommodated in the hub 10.
Furthermore, by using a rack and pinion as the linear motion rotation conversion mechanism of the linear motion rotation conversion unit 8, it is possible to align the longitudinal direction of each of the racks A1 to A3 with the linear motion direction of the linear body 11, and also to align the circumferential direction of each of the pinions B1 to B3 with the circumferential direction of each of the support shafts M1 to M3. Therefore, the arrangement of the three rack and pinions can be compactly arranged around the linear motion body 11, and even when three rack and pinions are provided corresponding to each of the rotors H1 to H3, it is possible to accommodate the linear motion rotation conversion unit 8 within the hub 10 while preventing the hub 10 from becoming larger.

The configurations and operations of the rotation transmission unit 6 and the rotary-to-linear conversion unit 7 will be described in more detail below.
8(a) is a perspective view showing the configuration of the pitch variable motor, rotation transmission unit, and rotary-linear motion conversion unit of FIG. 6, and FIG. 8(b) is a perspective view showing the configuration after removing the support member and linear motion guide unit that support the rotary-linear motion conversion unit of FIG. 8(a).

8(a) and 8(b), the support member BJ1 can be fixed to the inner diameter portion 2D by the bolt J1. The bolt J1 can be arranged, for example, at the four corners of the support member BJ1. The support member BJ2 is fixed to the support member BJ1 by the bolt J2 and the support 31 with the gear G2 sandwiched between the support member BJ1 and the support member BJ2. The bolt J2 can be arranged, for example, at both ends of the support member BJ2. Both shaft ends of the gear G2 are rotatably supported by the support members BJ1 and BJ2 via bearings. The support member BJ3 can be fixed to the inner diameter portion 2D by the bolt J3. The bolt J3 can be arranged, for example, at two locations at the ends of the support member BJ3. The pitch variable motor 5 can be fixed to the support member BJ3 by the bolt J4.

The ball screw nut 7G includes a flange 7A. The flange 7A has a shape obtained by cutting a cylinder along two parallel planes, and a protruding portion of the flange 7A is disposed in an opening of the linear guide portion 7E. The flange 7A can be provided integrally with the ball screw nut 7G.
The linear motion transmission shaft 7D includes a flange 7B and a guide surface 7C. The guide surface 7C includes a sliding member 7H. The flange 7B and the guide surface 7C are shaped like a cylinder cut by two parallel planes, and the flange 7B is disposed in the opening of the linear motion guide portion 7E.

The flat surface of flange 7B and guide surface 7C may be an integral plane. This flat surface may be two surfaces facing in opposite directions. The protruding portions of flanges 7A and 7B may be provided with an area into which bolt J5 can be inserted. With flanges 7A and 7B overlapping, flange 7A can be fixed to flange 7B with bolt J5, thereby fixing linear motion transmission shaft 7D to ball screw nut 7G.

A recess into which the sliding member 7H can be inserted can be provided on the flat surface or guide surface 7C of the flange 7B. The sliding member 7H can then be inserted into the recess and fixed to the flange 7B with adhesive or the like. At this time, the sliding member 7H protrudes from the flat surface. The material of the sliding member 7H is, for example, resin.

On the other hand, a flat surface can be provided on the inside of the linear guide portion 7E, which faces the flat surfaces of the flanges 7A, 7B and the guide surface 7C. Then, the sliding member 7H slides on the flat surface of the linear guide portion 7E in accordance with the linear motion LM of the linear transmission shaft 7D, thereby restricting the motion of the linear transmission shaft 7D in the axial direction of the rotation axis S0.

Here, by providing flat surfaces on parts of the outer periphery of the flanges 7A and 7B and on the guide surface 7C, and providing protrusions on the flanges 7A and 7B into which the bolt J5 can be inserted, and arranging the protrusions at the opening of the linear guide section 7E, the outer diameter of the linear guide section 7E can be reduced, and the rotary-to-linear conversion section 7 can be housed within the rotor shaft 4 while suppressing an increase in the diameter of the rotor shaft 4 in the thrust generating motor 2.

The configuration and operation of the linear motion/rotation conversion unit 8 will be described in more detail below.
Figure 9 is an exploded perspective view showing the configuration of the hub in Figure 1(b), Figure 10 is a top view showing the positional relationship between the linear body to which the rack in Figure 3 is attached and the pinion, Figure 11(a) is a perspective view showing the position of the linear body corresponding to the pitch angle of the rotor in Figure 1(b), and Figure 11(b) is a perspective view showing the position of the linear body corresponding to the pitch angle of the rotor in Figure 1(c).

In Figures 9, 10, 11(a) and 11(b), the linear motion rotation conversion unit 8 is provided with a lift guide 19 and nuts S1-S3 to limit the range of movement in the linear motion direction. The lift guide 19 is provided with a guide base 13 and guide pins T1-T3. The guide base 13 is provided with an opening 14 through which the tip of the linear motion transmission shaft 7D can pass. The linear body 11 is provided with an opening 12, openings V1-V3 and surfaces Z1-Z3. The hub 10 is provided with a case 21, an outer lid 22 and an inner lid 23. The case 21 is provided with a storage section 21A, hollow sections Q1-Q3, openings 21B and openings K1-K3. The inner lid 23 is provided with a through hole 23A.

Each of the faces Z1 to Z3 is provided at a position where the linear body 11 has three-fold rotational symmetry around the rotation axis S0. With three-fold rotational symmetry, the shape after rotation can be superimposed on the shape before rotation every time the linear body 11 is rotated by 120° around the rotation axis S0. Each of the faces Z1 to Z3 can support the racks A1 to A3, respectively. At this time, each of the faces Z1 to Z3 supports the racks A1 to A3 at a position where the teeth of the racks A1 to A3 face the direction of the teeth of the pinions B1 to B3.
The bearing U3 is inserted into the opening 12, and the linear motion transmission shaft 7D is further inserted into the inner ring of the bearing U3. The openings V1 to V3 can receive the guide pins T1 to T3, respectively.

The linear body 11 is supported by the outer ring of the bearing U3, and the tip of the linear transmission shaft 7D is fixed to the inner ring of the bearing U3 by a nut 15. The outer ring of the bearing U3 can be attached to the linear body 11 by, for example, a C-shaped retaining ring 16.

The guide base 13 supports the guide pins T1 to T3 in an upright position. The guide pins T1 to T3 can be provided integrally with the guide base 13. The planar shape of the guide base 13 can be made equal to the planar shape of the linear body 11. The positions of the openings V1 to V3 can correspond to the positions of the guide pins T1 to T3.

Opening 21B allows the linear body 11, to which racks A1 to A3 are attached, to be inserted into storage section 21A together with guide base 13. Each opening K1 to K3 allows each support shaft M1 to M3 to be inserted into case 21.

The accommodation section 21A accommodates the linear body 11 to which the racks A1 to A3 are attached together with the guide base 13 in the case 21. The accommodation section 21A is, for example, a hollow section or a recess provided in the case 21. The planar shape of the accommodation section 21A can correspond to the planar shape of the guide base 13. In this case, the planar shape of the accommodation section 21A can be three-fold rotationally symmetric around the rotation axis S0.

On the other hand, openings K1-K3 into which the support shafts M1-M3 can be inserted can be arranged along the outer circumferential surface of the housing 21A. In this case, the case 21 can be provided with a hollow portion Q1 into which the support shaft M1, pinion B1, bearing E1 and adapter D1 can be inserted, a hollow portion Q2 into which the support shaft M2, pinion B2, bearing E2 and adapter D2 can be inserted, and a hollow portion Q3 into which the support shaft M3, pinion B3, bearing E3 and adapter D3 can be inserted. The support shafts M1-M3, pinions B1-B3, bearings E1-E3 and adapters D1-D3 can be inserted into the hollow portions Q1-Q3, respectively, via the openings 21B.

The tips of the guide pins T1 to T3 protrude outside the inner lid 23 through the through hole 23A. Then, with the tips of the guide pins T1 to T3 protruding outside the inner lid 23, nuts S1 to S3 are attached to the tips of the guide pins T1 to T3, allowing the guide base 13 to be positioned within the storage section 21A.

The inner lid 23 is supported by the case 21. The inner lid 23 can be fixed to the case 21 with bolt J7. The outer lid 22 covers the inner lid 23. The outer lid 22 can be fixed to the inner lid 23. The material of the inner lid 23 is, for example, duralumin, and the material of the outer lid 22 is, for example, resin.

The linear body 11 with the racks A1 to A3 attached is then stored in the storage section 21A. The support shafts M1 to M3 with the pinions B1 to B3 attached are stored in the hollow sections Q1 to Q3. At this time, as shown in FIG. 10, the support shafts M1 to M3 are arranged so that their respective rotation axes JS1 to JS3 face in perpendicular directions JD1 to JD3 to the faces Z1 to Z3 of the linear body 11. The racks A1 to A3 are then supported on the faces Z1 to Z3 at positions where they mesh with the pinions B1 to B3.

In association with the linear motion of the linear transmission shaft 7D, the racks A1 to A3 move linearly together with the linear body 11. At this time, the motion of the linear body 11 is guided by the guide pins T1 to T3, and the range of movement of the linear body 11 in the linear direction is limited by the guide base 13 and nuts S1 to S3. In association with the linear motion of the racks A1 to A3, the pinions B1 to B3 rotate, respectively, and in association with the rotation of the pinions B1 to B3, the support shafts M1 to M3 rotate about their respective axes. In addition, in association with the rotation of the support shafts M1 to M3, the rotors H1 to H3 rotate, and the pitch angles θ1 to θ3 of the rotors H1 to H3 are changed. For example, when the linear body 11 is in the position shown in FIG. 11(a), the pitch angles θ1 to θ3 of each of the rotors H1 to H3 are set as shown in FIG. 1(b), and when the linear body 11 is in the position shown in FIG. 11(b), the pitch angles θ1 to θ3 of each of the rotors H1 to H3 are set as shown in FIG. 1(c).

The faces Z1 to Z3 are provided at positions that are three times rotationally symmetric around the axis of rotation S0, and the racks A1 to A3 are arranged on the faces Z1 to Z3. Therefore, by linearly moving one linear body 11, three rotational movements can be generated around the axes of the three support shafts M1 to M3. This makes it possible to accommodate the linear motion rotation conversion unit 8 within the hub 10 while making it possible to vary the pitch of the three rotors H1 to H3.

In the above embodiment, each rotor H1 to H3 is disposed directly below the thrust generating device 1, and the thrust generating device 1 is attached to the bottom of the airframe. At this time, thrust is applied to the thrust generating motor 2 in the upward direction. Therefore, by varying the load capacity of the thrust generating motor 2 depending on the direction of thrust applied to the thrust generating motor 2, the thrust generating motor 2 can be made lighter.

The support structure for the bearings of the thrust generating motor 2 will now be described in detail.
FIG. 12 is an enlarged cross-sectional view of the EA portion of FIG. 7(b), FIG. 13 is an exploded perspective view showing the configuration of the thrust generating motor of FIG. 1(a) when viewed diagonally from above, and FIG. 14 is an exploded perspective view showing the configuration of the thrust generating motor of FIG. 1(a) when viewed diagonally from below.

In Figures 12 to 14, the thrust generating motor 2 includes a stator case 40. The stator case 40 can accommodate the stator 2A in a position facing the rotor 2B. The stator case 40 rotatably supports the rotor shaft 4 of the rotor 2B via the bearing U1. The stator case 40 receives the axial load applied to the bearing U1. Here, the stator case 40 has a different load capacity depending on the direction of the axial load applied to the bearing U1. At this time, the stator case 40 can only withstand the axial load in one direction (upward in the thrust generating device 1 dedicated to the pusher).

The rotor shaft 4 also has different load resistances depending on the direction of the axial load applied to the bearing U1. In this case, the rotor shaft 4 can only withstand axial loads in one direction (upward in the case of the thrust generating device 1 dedicated to the pusher).

Specifically, the stator case 40 includes an outer frame 2C, an inner diameter portion 2D, a mounting surface 1A, a support portion 1C, and a spacer 2F. The bearing U1 includes an outer ring U11 and an inner ring U12.

The inner peripheral surface of the inner diameter portion 2D can come into contact with the outer peripheral surface of the outer ring U11. A step DS1 (first load receiving portion) that can come into contact with the axial end surface of the outer ring U11 is provided on the inner peripheral surface of the inner diameter portion 2D. In this case, the step DS1 can only be provided on the axial end surface of the outer ring U11 that faces the mounting surface of the flying object HSB (the upper end surface in the case of a thrust generating device 1 dedicated to a pusher).

The inner peripheral surface of the inner ring U12 can come into contact with the outer peripheral surface of the rotor shaft 4. A step DS2 (second load receiving portion) that can come into contact with the axial end surface of the inner ring U12 is provided on the outer peripheral surface of the rotor shaft 4. In this case, the step DS2 can only be provided on the axial end surface of the inner ring U12 opposite the mounting surface of the flying object HSB (the lower end surface in the case of the thrust generating device 1 dedicated to the pusher).

Here, in the thrust generating device 1 dedicated to the pusher, the thrust F of the rotor blades H1 to H3 is applied to the thrust generating motor 2 so that the thrust generating motor 2 is pushed from below. At this time, the thrust F of the rotor blades H1 to H3 is applied to the lower end surface of the inner ring U12 via the step DS2 of the rotor shaft 4, and the load acting as a reaction to the thrust F applied to the lower end surface of the inner ring U12 can be received by the step DS2 of the rotor shaft 4. Furthermore, the thrust F applied to the lower end surface of the inner ring U12 is applied to the step DS1 of the inner diameter portion 2D via the upper end surface of the outer ring U11, and the load applied via the upper end surface of the outer ring U11 can be received by the step DS1 of the inner diameter portion 2D. Therefore, the axial load applied to the bearing U1 can be received by the steps DS1 and DS2 while the rotor shaft 4 is rotatably supported via the bearing U1.

Here, by providing the step DS1 of the inner diameter portion 2D only on the upper end surface side of the outer ring U11, it is no longer necessary to provide a step on the lower end surface side of the outer ring U11, and the inner diameter portion 2D can be made thinner on the lower end surface side of the outer ring U11. By providing the step DS2 of the rotor shaft 4 only on the lower end surface side of the inner ring U12, it is no longer necessary to provide a step on the upper end surface side of the inner ring U12, and the rotor shaft 4 can be made thinner on the upper end surface side of the inner ring U12. This makes it possible to reduce the weight of the inner diameter portion 2D and the rotor shaft 4 compared to a case in which the load capacity is provided against axial loads in both directions, and it is possible to reduce the weight of the thrust generating motor 2 while receiving the thrust F of the rotor blades H1 to H3.

Meanwhile, a plate 43 is provided on the other side of the axial end face of the outer ring U11 (the lower end face of the outer ring U11 in the thrust generating device 1 dedicated to the pusher). The plate 43 supports the other side of the axial end face of the outer ring U11. The plate 43 can be fixed to the inner diameter portion 2D with a bolt J8. This makes it possible to position the outer ring U11 while preventing the thrust generating motor 2 from becoming heavy, even if a step DS1 is provided only on the mounting surface side of the flying object HSB of the axial end face of the outer ring U11.

A snap ring 41 is provided on the other side of the axial end face of the inner ring U12 (the upper end face of the inner ring U12 in the thrust generating device 1 dedicated to the pusher). The snap ring 41 supports the other side of the axial end face of the inner ring U12. The snap ring 41 can be fixed to the outer peripheral surface of the rotor shaft 4. This makes it possible to position the inner ring U12 while preventing the thrust generating motor 2 from becoming heavy, even if a step DS2 is provided only on the side of the axial end face of the inner ring U12 opposite the mounting surface of the flying object HSB.

A cover 42 is provided on the bearing U1. The cover 42 can cover the upper end surface of the bearing U1. In this case, the cover 42 can be ring-shaped to correspond to the planar shape of the upper end surface of the bearing U1. The cover 42 can be fixed to the inner circumferential surface of the inner diameter portion 2D by bolts or the like.

A thrust generating device according to the second embodiment will be described below. In the above-described first embodiment, an example was described in which an extension 9 having a flange 9A was used as a spacer for maintaining the distance between the thrust generating motor 2 and the rotors H1 to H3. In the second embodiment, an example is described in which an extension 9' without a flange 9A is used as a spacer for maintaining the distance between the thrust generating motor 2 and the rotors H1 to H3.
In the following description, the same components as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

15(a) is a perspective view showing the state in which the rotor is attached to the thrust generating device according to the second embodiment, 15(b) and 15(c) are side views showing the state in which the pitch angle of the rotor attached to the thrust generating device according to the second embodiment is changed, 16 and 17 are perspective views showing the configuration of the thrust generating device of FIG. 15(a) in an exploded form, 18(a) and 18(b) are perspective views showing the configuration of the thrust generating device of FIG. 16 and 17 after assembly, 19(a) and 20(a) are plan views showing the configuration of the thrust generating device according to the second embodiment, 19(b) is a cross-sectional view taken along line A-A in FIG. 19(a), and 20(b) is a cross-sectional view taken along line B-B in FIG. 20(a).

In Figures 15(a), 15(b), 15(c), 16, 17, 18(a), 18(b), 19(a), 19(b), 20(a) and 20(b), the thrust generator 1' has an extension 9' instead of the extension 9 of the thrust generator 1 in Figure 1(b). The rest of the configuration of the thrust generator 1' is the same as that of the thrust generator 1 in Figure 1(b).

The extension 9' is a spacer for maintaining a distance between the thrust generating motor 2 and the rotor blades H1 to H3 in the axial direction of the rotation shaft S0. The extension 9' prevents the rotor blades H1 to H3 from colliding with the thrust generating motor 2. The extension 9' is fixed to the rotor shaft 4 via the mounting portion 4A and rotates together with the rotor shaft 4. At this time, the hub 10 is fixed to the rotor shaft 4 via the extension 9'. The extension 9' can be cylindrical in order to pass the linear transmission shaft 7D in the axial direction of the rotor shaft 4. The extension 9' can be configured in the same way as the extension 9, except that the extension 9 in FIG. 2 does not have the flange 9A.

A method for attaching the hub 10 to the end face side of the rotor shaft 4 via the extension 9' will be specifically described below.
21 is an exploded perspective view showing the configuration of the hub and extension in FIG. 15(b), FIG. 22 is an exploded perspective view showing the configuration of the mounting portion, case and extension in FIG. 15(b), and FIG. 23 is a bottom view showing the configuration of the case in FIG. 22.

21 to 23, the accommodating section 21A of the case 21 has a top surface 21D. The top surface 21D is located on the side where the extension 9' is attached. The top surface 21D is provided with a circular opening 21C and through holes WA1 to WA3. The through holes WA1 to WA3 can be arranged in three locations around the opening 21C. The through holes WA1 to WA3 can each be inserted with a bolt W1 to W3. The extension 9' has a step 9B and through holes WB1 to WB3. The step 9B protrudes in the axial direction of the rotor shaft 4 on the inner surface side of the extension 9'. The step 9B can be inserted into the opening 21C. The through holes WB1 to WB3 penetrate the extension 9' in the axial direction of the rotor shaft 4. The through holes WB1 to WB3 can each be inserted with a bolt W1 to W3. The mounting portion 4A has female threads WC1 to WC3. The female threads WC1 to WC3 are located on the mounting surface side of the extension 9'. Each of the through holes WA1 to WA3, WB1 to WB3 and each of the female threads WC1 to WC3 can be positioned to correspond to the insertion positions of each of the bolts W1 to W3. The inner lid 23 has a through hole 23D into which the screw J7 can be inserted. At this time, the outer lid 22 can cover the inner lid 23 so as to block the through hole 23D.

Then, the step 9B is inserted into the opening 21C, and the top surface 21D of the case 21 is butted against the lower end side of the extension 9'. Then, the bolts W1 to W3 are inserted into the housing portion 21A, protruded from the case 21 through the through holes WA1 to WA3, and further protruded from the extension 9' through the through holes WB1 to WB3, and screwed into the female threads WC1 to WC3, thereby fixing the case 21 and the extension 9' to the mounting portion 4A. At this time, the case 21 and the extension 9' can be fixed to the mounting portion 4A with the bolts W1 to W3 housed in the case 21 and the extension 9'. This makes it possible to prevent the bolts W1 to W3 from being exposed to the outside of the thrust generator 1', and prevents the bolts W1 to W3 from falling off the thrust generator 1' while reducing the weight of the thrust generator 1' in FIG. 15(a) compared to the thrust generator 1 in FIG. 1(a).

As shown in FIG. 21, a knock pin 9E can be inserted between the opposing surfaces of the case 21 and the extension 9', and a marker pin 9F can be inserted between the opposing surfaces of the mounting portion 4A and the extension 9'. Three knock pins 9E and three marker pins 9F can be provided, corresponding to the number of bolts W1 to W3. At this time, the knock pins 9E and the bolts W1 to W3 can be arranged alternately in the circumferential direction on the lower end surface side of the extension 9'. Also, the marker pins 9F and the bolts W1 to W3 can be arranged alternately in the circumferential direction on the mounting portion 4A. This makes it possible to improve the positioning accuracy of the case 21 and the extension 9' while ensuring a clearance for screwing the case 21 and the extension 9' to the mounting portion 4A, and to release the circumferential torque applied to the bolts W1 to W3.

Then, with the linear body 11, racks A1-A3, and pinions B1-B3 arranged in the accommodation section 21A, the inner lid 23 is attached to the case 21 so as to close the opening 21B. Then, with the screw J7 inserted into the through hole 23D, the screw J7 is screwed into the case 21 to fix the inner lid 23 to the case 21. Then, the outer lid 22 is attached to the inner lid 23 so as to close the through hole 23D into which the screw J7 has been inserted. This makes it possible to prevent the screw J7 from being exposed to the outside of the thrust generating device 1' and also makes it possible to prevent the screw J7 from falling off.

The case 21 and the mounting part 4A are common to the thrust generator 1 in FIG. 1(b) and the thrust generator 1 in FIG. 15(b). Therefore, if the extension 9' in FIG. 16 does not have sufficient mounting strength, it can be replaced with the extension 9 in FIG. 2 without modifying the case 21 and the mounting part 4A.

In the above-described embodiment, the extension 9 in FIG. 1(b) or the extension 9' in FIG. 15(b) is provided to maintain the distance between the thrust generating motor 2 and the rotors H1 to H3. However, if the distance between the thrust generating motor 2 and the rotors H1 to H3 can be sufficiently maintained without the extension 9 or the extension 9', the extension 9 or the extension 9' may not be required. If the extension 9 in FIG. 1(b) is not provided, the flange 9A may be provided on the case 21. If the extension 9' in FIG. 15(b) is not provided, the bolts W1 to W3 can be shortened by the distance provided by the extension 9', and the case 21 can be directly fixed to the mounting portion 4A using the bolts W1 to W3.

1 Thrust generating device, H1-H3 rotor blades, P1-P3 grip, 2 thrust generating motor, 2A stator, 2B rotor, 3A, 3B hollow section, 4 rotor shaft, 5 pitch variable motor, 6 rotation transmission section, 7 rotation-linear conversion section, 8 linear-rotation conversion section, 9 extension

Claims (4)

A first motor that generates thrust for the rotor;
A second motor that generates a rotational motion that changes the pitch angle of the rotor;
a first conversion unit that converts the rotational motion of the second motor into a linear motion;
a second conversion unit that converts the linear motion converted by the first conversion unit into a rotational motion,
The first motor is
A rotor,
A stator;
a stator case capable of housing the stator at a position facing the rotor;
a bearing that rotatably supports a rotor shaft of the rotor,
The stator case includes a first load receiving portion that receives an axial load applied to the bearing,
The first load receiving portion has a different load capacity depending on the direction of the axial load, and is provided only on the mounting surface side of the flying object of the axial end surface of the outer ring of the bearing, and includes a first step that can contact the axial end surface of the outer ring of the bearing on the mounting surface side,
The rotor shaft includes a second load receiving portion that receives an axial load applied to the bearing that is integrally formed with the rotor shaft,
The second load receiving portion has a load capacity that varies depending on the direction of the axial load, and is provided only on the opposite side to the mounting surface of the flying object, and includes a second step that can contact the axial end surface of the inner ring of the bearing on the opposite side,
a thrust generating device that generates a thrust force that pushes the first motor from the opposite side to the mounting surface toward the mounting surface by the rotational motion of the rotor . 2. The thrust generating device according to claim 1 , further comprising a plate that is provided on an axial end surface of the outer ring of the bearing opposite to a mounting surface for the flying object and that can be attached to the stator case. The stator case is
an inner diameter portion that supports the rotor shaft via the bearing;
3. The thrust generating device according to claim 1, further comprising a frame that is provided radially outside the inner diameter portion and supports the stator at a position facing the rotor. 4. The thrust generating device according to claim 1, further comprising a snap ring that is provided on an axial end surface of the inner ring of the bearing on a mounting surface side of the flying object and can be attached to the rotor shaft.

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