JP7468018B2 - Thrust generating device - Google Patents

Description

The present invention relates to a thrust generating device.

A technology for electrically changing the pitch of a propeller (rotor blades) without using hydraulics is disclosed, for example, in Patent Document 1. In this technology, the main rotating shaft is formed to be hollow, and an operating rod is arranged concentrically within this main rotating shaft so that it can move only in the axial direction, and an arm fixed to the lower end of the operating rod is connected to each support shaft of the blades via a link and lever mechanism. Then, by moving the operating rod back and forth in the axial direction, the mounting angle of each blade is changed via the link and lever mechanism.

Japanese Patent Application Laid-Open No. 5-87037

High reliability is required for safety reasons for flyable aircraft such as multicopters, airplanes, rotorcraft, and flyable automobiles.

The present invention aims to provide a highly reliable thrust generating device.

A thrust generating device according to one aspect of the present invention comprises a thrust generating motor that generates thrust by rotating a plurality of rotors, a plurality of pitch angle changing motors that change the pitch angle of the rotors, a plurality of rotation transmission units respectively connected to the plurality of pitch angle changing motors, a first motion conversion unit having a single linear shaft and a motion conversion mechanism, the motion conversion mechanism being connectable to the plurality of rotation transmission units and the linear shaft and converting rotation of at least one rotation transmission unit into linear motion of the linear shaft, and a second motion conversion unit that converts the linear motion of the linear shaft into rotational motion to change the pitch angle of the rotors.
In this embodiment, the first motion conversion unit can convert the rotational motion of the multiple pitch angle change motors into linear motion of a single linear shaft, and if any of the pitch angle change motors fails, it is possible to change the pitch angle of the rotor using the rotational motion of the other pitch angle change motors, thus providing a thrust generating system with high reliability.

Preferably, the motion converting mechanism of the first motion converting part is constantly connected to the plurality of rotation transmitting parts and is capable of converting rotation of the plurality of rotation transmitting parts into linear motion of the linear motion shaft.
In this case, if any of the pitch angle changing motors fails, it is possible to immediately change the pitch angle of the rotor blades by the other pitch angle changing motor.

Preferably, the pitch angle changing motor is disposed inside the thrust generating motor and fixed to a stationary member of the thrust generating motor.
In this case, it is possible to prevent the thrust generating device from becoming large.

FIG. 1 is a perspective view showing a thrust generating device according to an embodiment to which rotors are attached. FIG. 2 is a side view showing a thrust generating device according to an embodiment having rotors attached thereto. FIG. 3 is a side view showing a thrust generating device according to an embodiment having rotors attached thereto. FIG. 4 is an exploded perspective view of the thrust generating device according to the embodiment. FIG. 5 is an exploded perspective view of the thrust generating device according to the embodiment as viewed from another direction. FIG. 6 is a plan view of the thrust generating device according to the embodiment. 7 is a cross-sectional view taken along line VII-VII of FIG. FIG. 8 is a plan view of two rotation transmission units and a rotary-to-linear motion conversion unit of the thrust generating device according to the embodiment. FIG. 9 is a cross-sectional view taken along line IX-IX of FIG. FIG. 10 is a cross-sectional view taken along line X-X of FIG. FIG. 11 is a perspective view of two rotation transmission units and a rotary-to-linear conversion unit of the thrust generating device according to the embodiment. FIG. 12 is a perspective view showing a linear body of the linear motion-rotation converting unit of the thrust generating device according to the embodiment, and the position of the linear body corresponds to the pitch angle of the rotor in FIG. FIG. 13 is a perspective view showing a linear moving body, the position of which corresponds to the pitch angle of the rotor blades in FIG. FIG. 14 is an exploded perspective view of a hub of the thrust generating device according to the embodiment.

The following describes in detail the embodiments of the present invention with reference to the accompanying drawings. 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. The drawings are not necessarily drawn to scale, and some features may be exaggerated or omitted.

In the following explanation, we will use an example in which the rotor driven by the thrust generating device has three blades, but the number of blades driven by the thrust generating device is not necessarily limited to three, and may be N (N is a positive integer).

Figure 1 is a perspective view showing a thrust generating device according to an embodiment in which rotors are attached. Figures 2 and 3 are side views showing thrust generating devices according to an embodiment in which rotors are attached, with the rotors having different pitch angles.

As shown in Figures 1 to 3, the thrust generating device 1 rotates a rotor or propeller R having multiple rotors H1 to H3. The propeller R is disposed directly below the thrust generating device 1. The propeller R has grips P1 to P3, which support the rotors H1 to H3 so that they extend radially in the horizontal direction from the thrust generating device 1.

The thrust generating device 1 is attached to the airframe of the flying object via the upper mounting part 1A. The flying object to which the thrust generating device 1 is attached is, for example, a flying object or vehicle such as a motor-driven multicopter, an airplane, a rotorcraft, or an automobile with flying capabilities. Although not shown, multiple thrust generating devices 1 with propellers R attached may be attached to the airframe of the flying object.

The thrust generating device 1 comprises a thrust generating motor 2, two pitch angle changing motors 5A, 5B, and a motion transmission unit 6. The thrust generating motor 2 rotates the propeller R to generate thrust to be applied to the flying object. Each of the two pitch angle changing motors 5A, 5B changes the pitch angles θ1 to θ3 of the rotors H1 to H3. By changing the pitch angles θ1 to θ3 of the rotors H1 to H3, it is possible to change the thrust to be applied to the flying object. The motion transmission unit 6 transmits the rotational motion of the pitch angle changing motors 5A, 5B to the rotors H1 to H3.

Figures 4 and 5 are exploded perspective views of the thrust generating device 1. Figure 6 is a plan view of the thrust generating device 1, and Figure 7 is a cross-sectional view taken along line VII-VII in Figure 6. As shown in Figures 4 to 7, the thrust generating motor 2 comprises a stator 2A, a rotor 2B, and a frame 2C. The rotor 2B comprises a rotor shaft 4 and hollow portions 3A, 3B, and 3C on the radially inner side.

The stator 2A is composed of an electromagnetic steel plate and windings, and is located outside the rotor 2B. The stator 2A is fixed to the annular portion of the frame 2C, which is arranged outside the stator 2A. The mounting portion 1A of the thrust generating device 1 can be provided in the center of the frame 2C. The mounting portion 1A has an opening 1B, into which the motion transmission unit 6 is inserted. The mounting portion 1A is connected to the annular portion via a plurality of spokes 1C extending radially. The frame 2C is formed with an inner cylindrical portion 1D, which rotatably supports the rotor shaft 4 via a bearing U1. The frame 2C, including the annular portion, the mounting portion 1A, the spokes 1C, and the inner cylindrical portion 1D, can be formed, for example, by cutting an alloy such as duralumin.

The rotor 2B of the thrust generating motor 2 is connected to the rotor shaft 4 via multiple spokes 2D extending radially. The rotor 2B rotates together with the rotor shaft 4 around the central axis S0 (see Figures 2 and 3). The rotor 2B and the rotor shaft 4 are supported by the frame 2C via a bearing U1.

The hollow sections 3A and 3B are provided between the rotor 2B and the rotor shaft 4. Pitch angle change motors 5A and 5B are disposed in the hollow sections 3A and 3B, respectively. The pitch angle change motors 5A and 5B are fixed to the frame 2C. However, for ease of understanding, the pitch angle change motor 5B is omitted from the illustration in Figures 4 and 5.

The hollow portion 3C is the central hole of the rotor shaft 4 and extends along the axial direction of the rotor shaft 4. A part of the motion transmission unit 6 is inserted into the hollow portion 3C.

A hollow cylindrical extension 9 is fixed to the lower end surface of the rotor shaft 4 of the thrust generating motor 2, and the extension 9 is fixed to the hub 10 of the rotor R. The hub 10 is therefore supported by the frame 2C in a state in which it can rotate around the central axis S0. Grips P1-P3 that support the rotor blades H1-H3 are attached to the hub 10. In this way, the thrust generating motor 2 rotates the propeller R having the rotor blades H1-H3. That is, when the thrust generating motor 2 operates and the rotor 2B rotates, the rotor shaft 4 rotates, and the rotor blades H1-H3 rotate around the central axis S0. As the rotor blades H1-H3 rotate, thrust is generated and applied to the flying object.

The extension 9 is a spacer that maintains a gap between the thrust generating motor 2 and the rotors H1 to H3 in the axial direction of the thrust generating device 1, and prevents the rotors H1 to H3 from colliding with the thrust generating motor 2. The material of the extension 9 is, for example, duralumin.

Pitch angle change motors 5A, 5B, which change the pitch angle of rotor blades H1 to H3, are fixed to frame 2C of thrust generating motor 2 and are disposed inside thrust generating motor 2, specifically, in hollow portions 3A, 3B, respectively. The rotation shafts of pitch angle change motors 5A, 5B extend vertically, similar to rotor shaft 4 of thrust generating motor 2. In other words, the rotation shafts of pitch angle change motors 5A, 5B and rotor shaft 4 are different parallel shafts.

Next, we will explain the motion transmission unit 6 that transmits the rotational motion of the pitch angle change motors 5A and 5B to the rotors H1 to H3. The motion transmission unit 6 includes rotation transmission parts 6A and 6B, a rotary-to-linear conversion part 7, and a linear-to-rotary conversion part 8.

The rotation transmission unit 6A transmits the rotation of the rotating shaft of the pitch angle change motor 5A to the ball screw shaft 7F of the rotary-linear motion conversion unit 7. The rotation transmission unit 6B transmits the rotation of the rotating shaft of the pitch angle change motor 5B to the ball screw shaft 7F of the rotary-linear motion conversion unit 7. The ball screw shaft 7F extends vertically along the central axis S0 of the thrust generating device 1 and is disposed in the hollow portion 3C, which is the central hole of the rotor shaft 4. Therefore, the rotation transmission unit 6A transmits the rotational motion of the pitch angle change motor 5A to the shaft on the central axis S0, and the rotation transmission unit 6B transmits the rotational motion of the pitch angle change motor 5B to the shaft on the central axis S0. Each rotation transmission unit has a rotating member that rotates with the rotation of the rotating shaft of the pitch angle change motor. The rotation transmission units 6A and 6B are fixed to the frame 2C.

The rotary-linear motion conversion unit (first motion conversion unit) 7 has a linear motion transmission shaft (linear motion shaft) 7D that extends vertically along the central axis S0 of the thrust generating device 1, and a motion conversion mechanism that converts the rotation of the rotary motion transmission units 6A, 6B into linear motion of the linear motion transmission shaft 7D. The motion conversion mechanism of the rotary-linear motion conversion unit 7 is connected to the rotary motion transmission units 6A, 6B and the linear motion transmission shaft 7D. This motion conversion mechanism has a ball screw shaft 7F that is coaxially arranged above the linear motion transmission shaft 7D. The upper part of the rotary-linear motion conversion unit 7 is housed within the thrust generating motor 2, but the lower part of the rotary-linear motion conversion unit 7 protrudes downward from the thrust generating motor 2. The rotary-linear motion conversion unit 7 is fixed to the frame 2C.

The linear motion-rotation conversion unit (second motion conversion unit) 8 converts the linear motion of the linear motion transmission shaft 7D of the rotary-linear motion conversion unit 7 into rotational motion to change the pitch angle of the rotors H1 to H3. The linear motion-rotation conversion unit 8 is located below the thrust generating motor 2.

The pitch angle change motors 5A, 5B, the rotation transmission units 6A, 6B, and the rotary-linear conversion unit 7 are fixed to the frame (stationary member) 2C of the thrust generating motor 2. Therefore, even if the rotor shaft 4 rotates, the pitch angle change motors 5A, 5B, the rotation transmission units 6A, 6B, and the rotary-linear conversion unit 7 do not rotate around the rotor shaft 4. On the other hand, the linear-rotation conversion unit 8 is supported by the rotor shaft 4. Therefore, the linear-rotation conversion unit 8 rotates around the rotor shaft 4 as the rotor shaft 4 rotates.

As shown in Figures 8 to 11, a gear G1 is fixed to the upper end of the ball screw shaft 7F of the rotary-linear conversion unit 7. The rotation transmission unit 6A has gears G2 and G3, with the gear G3 fixed to the rotation shaft of the pitch angle change motor 5A, and the gear G2 meshing with the gears G3 and G1. The rotation transmission unit 6B also has gears G2 and G3, with the gear G3 fixed to the rotation shaft of the pitch angle change motor 5B, and the gear G2 meshing with the gears G3 and G1. Therefore, in the rotation transmission unit 6A, the gears G3 and G2 can transmit the rotational motion of the pitch angle change motor 5A to the ball screw shaft 7F fixed to the gear G1, and in the rotation transmission unit 6B, the gears G3 and G2 can transmit the rotational motion of the pitch angle change motor 5B to the ball screw shaft 7F fixed to the gear G1. The material of the gears G1 to G3 is, for example, carbon steel.

The rotary-linear converter 7 is supported by a support member F1. As shown in Figs. 4, 6 and 7, the support member F1 is disposed in an opening 1B of the mounting portion 1A of the frame 2C of the thrust generating motor 2. The support member F1 is supported on the frame 2C by, for example, four bolts J1 (see Figs. 8 to 11). The bolts J1 can be disposed, for example, at the four corners of the support member F1. Two support members F3 are disposed in the hollow portions 3A and 3B of the thrust generating motor 2. These support members F3 are also supported on the frame 2C by bolts J3 (see Figs. 8, 9 and 11). The pitch angle changing motor 5A is fixed to the support member F3 in the hollow portion 3A by bolts J4, and the pitch angle changing motor 5B is fixed to the support member F3 in the hollow portion 3B by bolts J4 (see Figs. 8 to 11).

As shown in Figures 8 to 11, two support members F2 are supported by bolts J2 on the support member F1, and the support member F1 and one of the support members F2 rotatably support the gear G2 of the rotation transmission unit 6A, and the support member F1 and the other support member F2 rotatably support the gear G2 of the rotation transmission unit 6B. The material of the support members F1 to F3 is, for example, an aluminum alloy.

In this embodiment, in the rotation transmission unit 6A, a gear transmits the rotational motion of the pitch angle change motor 5A to the ball screw shaft 7F of the rotary-linear motion conversion unit 7, and in the rotation transmission unit 6B, a gear transmits the rotational motion of the pitch angle change motor 5B to the ball screw shaft 7F of the rotary-linear motion conversion unit 7. However, each rotation transmission unit may have a belt-pulley mechanism or a chain-sprocket. Specifically, multiple pulleys may be fixed to the ball screw shaft 7F, a belt may be wound around one pulley and a pulley fixed to the rotating shaft of the pitch angle change motor 5A, and a belt may be wound around another pulley and a pulley fixed to the rotating shaft of the pitch angle change motor 5B. A timing belt may be used as the belt. Multiple sprockets may be fixed to the ball screw shaft 7F, a chain may be wound around one sprocket and a sprocket fixed to the rotating shaft of the pitch angle change motor 5A, and a chain may be wound around the other sprocket and a sprocket fixed to the rotating shaft of the pitch angle change motor 5B.

In this embodiment, the rotary-linear conversion unit 7 uses a ball screw as a motion conversion mechanism to convert the rotary motion of the ball screw shaft 7F into linear motion of the linear transmission shaft 7D. The motion conversion mechanism includes a ball screw shaft 7F, a ball screw nut 7G, and a pair of linear guides 7E. However, a sliding screw or other feed screw may be used instead of the ball screw. In this embodiment, by using a ball screw as the motion conversion mechanism of the rotary-linear conversion unit 7, the drive torque required to change the pitch angle can be reduced compared to when a sliding screw is used, and power consumption of the pitch angle change motors 5A and 5B can be reduced.

The ball screw shaft 7F extends vertically. As shown in FIG. 7, the ball screw shaft 7F is rotatably supported by a bearing U2 fixed to the support member F1, and rotates about the longitudinal axis of the ball screw shaft 7F as the gear G1 rotates.

As shown in Figures 9 and 10, the ball screw nut 7G is engaged with the ball screw shaft 7F. The ball screw nut 7G also extends vertically and is fixed to a linear motion transmission shaft 7D that extends vertically and is located below the ball screw nut 7G.

As shown in Figures 9 to 11, the ball screw nut 7G and the linear transmission shaft 7D are sandwiched between linear guides 7E, which are a pair of parallel long plate walls protruding from the support member F1, and are restricted from rotating by the pair of linear guides 7E. As the ball screw shaft 7F rotates, the ball screw nut 7G and the linear transmission shaft 7D move linearly in the vertical direction along the axial direction of the ball screw shaft 7F. The linear guides 7E allow the linear motion of the ball screw nut 7G and the linear transmission shaft 7D. In other words, the linear guides 7E guide the ball screw nut 7G and the linear transmission shaft 7D to move linearly. Therefore, when the ball screw shaft 7F rotates together with the gear G1, the ball screw nut 7G and the linear transmission shaft 7D move linearly in the vertical direction, guided by the linear guides 7E. The linear guides 7E can be provided integrally with the support member F1.

As shown in Figures 9 and 10, a vertically extending cavity is formed at the top of the linear motion transmission shaft 7D, and a ball screw nut 7G meshed with the ball screw shaft 7F is inserted into this cavity.

As shown in Figures 10 and 11, two guided flat surfaces 7C are formed on the outer peripheral surface of the upper part of the linear motion transmission shaft 7D. The two guided flat surfaces 7C are parallel to each other and face the two linear motion guide portions 7E, respectively.

As shown in FIG. 10, a recess is formed in each of the guided flat surfaces 7C, and a sliding member 7H made of a low-friction material, such as fluororesin, is fitted into the recess. A part of the sliding member 7H protrudes from the recess and is in slidable contact with the linear guide portion 7E. Therefore, when the ball screw nut 7G and the linear transmission shaft 7D move linearly in the vertical direction, the sliding member 7H reduces friction with the linear guide portion 7E. The sliding member 7H may be fixed in the recess with an adhesive or the like.

As shown in Figures 9 to 11, a flange 7A is formed on the upper end of the ball screw nut 7G, and a flange 7B is also formed on the upper end of the linear motion transmission shaft 7D. The flanges 7A and 7B are shaped like a cylinder cut by two parallel planes, and the arc-shaped protruding portions of the flanges 7A and 7B are exposed from between a pair of linear motion guides 7E. The flanges 7A and 7B are fixed by bolt J5, and therefore the linear motion transmission shaft 7D is fixed to the ball screw nut 7G.

On the other hand, as shown in FIG. 10, the flat surfaces of the flanges 7A and 7B face the two linear guide sections 7E, respectively. The flat surface of the flange 7A is flush with the guided flat surface 7C. The flat surface of the flange 7B is part of the guided flat surface 7C, and the sliding member 7H is fitted into a recess formed therein. In this way, by providing flat surfaces on the flanges 7A and 7B, the outer diameter of the pair of linear guide sections 7E can be reduced, and the rotary-linear conversion section 7 can be housed within the rotor shaft 4 while suppressing an increase in the diameter of the rotor shaft 4.

As shown in FIG. 7, most of the rotary-linear converter 7, including the upper part of the linear transmission shaft 7D, is disposed inside the thrust generating motor 2, while the lower part of the linear transmission shaft 7D passes through the internal space of the extension 9, which is a hollow cylinder, and further reaches the inside of the hub 10 of the propeller R.

The lower part of the linear motion transmission shaft 7D is connected to a linear motion rotation conversion unit 8 that converts the linear motion of the rotary-linear motion conversion unit 7 into rotational motion in order to change the pitch angle of the rotors H1 to H3. In this embodiment, the linear motion rotation conversion unit 8 uses a rack and pinion as a motion conversion mechanism to convert the linear motion of the linear motion transmission shaft 7D of the rotary-linear motion conversion unit 7 into rotational motion.

As shown in Figures 4 and 5, 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, shaft adapters D1 to D3, and pinions B1 to B3.

The linear body 11 has a regular triangular prism shape with a cavity formed in its center. As shown in FIG. 7, the lower end of the linear transmission shaft 7D is fitted into the inner ring of the bearing U3, and the outer ring of the bearing U3 is fitted into the cavity of the linear body 11. Therefore, the linear body 11 can rotate around the linear transmission shaft 7D and moves linearly in the vertical direction together with the linear transmission shaft 7D. For example, a double row angular ball bearing can be used as the bearing U3.

The racks A1 to A3 are fixed to three corners of the linear body 11 and move linearly together with the linear body 11. The racks A1 to A3 are meshed with the pinions B1 to B3, respectively, and the pinions B1 to B3 are rotated simultaneously with the linear motion of the linear body 11 and the racks A1 to A3.

The support shafts M1 to M3 are arranged on the extensions of the grips P1 to P3 that support the rotors H1 to H3 of the propeller R. That is, the support shafts M1 to M3 support the grips P1 to P3 so as to extend horizontally radially from the thrust generating device 1. 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. However, 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 can be, for example, titanium.

The support shafts M1 to M3 are supported by bearings E1 to E3 fixed to the case 21 so that they can rotate around their own axes. For example, double row angular contact ball bearings can be used as E1 to E3.

The pinions B1 to B3 are fixed to the tips of the support shafts M1 to M3, respectively. Therefore, when the pinions B1 to B3 rotate in accordance with the linear motion of the linear body 11 and the racks A1 to A3, the support shafts M1 to M3 also rotate together with the grips P1 to P3. The material of the pinions B1 to B3 and the racks A1 to A3 is, for example, chrome molybdenum steel.

The case 21 is a part of the hub 10 of the propeller R. The case 21 houses the linear body 11, racks A1 to A3, support shafts M1 to M3, bearings E1 to E3, shaft adapters D1 to D3, and pinions B1 to B3. Therefore, the case 21 can also be considered as the case of the linear motion rotation conversion unit 8.

The upper part of the case 21 is fixed to the lower end of the extension 9, which is a hollow cylinder, and the upper end of the extension 9 is fixed to the rotor shaft 4 of the thrust generating motor 2. Therefore, the case 21 rotates around the axis of the thrust generating device 1 together with the rotor 2B and the rotor shaft 4.

The bearings E1 to E3 fixed to the case 21 can support the support shafts M1 to M3 against the centrifugal force acting on the rotors H1 to H3 when the thrust generating device 1 rotates around its axis.

The shaft adapters D1 to D3 are disposed outside the support shafts M1 to M3 and inside the bearings E1 to E3, respectively, and are supported by the support shafts M1 to M3. The inner circumferential surface of each shaft adapter D1 to D3 is formed to fit the outer circumferential surface of the support shafts M1 to M3, which vary in diameter, and the outer circumferential surface of each shaft adapter D1 to D3 is formed to fit the inner circumferential surface of the cylindrical bearings E1 to E3. The shaft adapters D1 to D3 allow the bearings E1 to E3 to support the support shafts M1 to M3 while accommodating changes in the diameter of each support shaft M1 to M3. The case 21 and the shaft adapters D1 to D3 are made of a material such as duralumin.

The linear body 11, racks A1-A3, support shafts M1-M3, bearings E1-E3, shaft adapters D1-D3, and pinions B1-B3 housed in the case 21 rotate together with the case 21 around the axis of the thrust generator 1. As described above, the linear body 11 is fixed to the outer ring of the bearing U3, and can rotate around the axis of the thrust generator 1 independently of the linear transmission shaft 7D fixed to the inner ring of the bearing U3. As shown in FIG. 7, the inner ring of the bearing U3 can be fixed to the lower end of the linear transmission shaft 7D by, for example, a nut 15, and the outer ring of the bearing U3 can be fixed to the linear body 11 by, for example, a C-shaped retaining ring 16.

Figure 12 shows the position of the linear body 11 corresponding to the pitch angle of the rotor in Figure 2, and Figure 13 shows the position of the linear body 11 corresponding to the pitch angle of the rotor in Figure 3. As shown in Figures 12 and 13, the linear motion rotation conversion unit 8 includes a base 13, lift guides T1-T3, and nuts S1-S3 to limit the range of movement of the linear body 11 in the linear direction. The base 13 is an equilateral triangular plate with the same outline as the linear body 11, and a through opening 14 is formed in the center of the base 13 through which the lower end of the linear transmission shaft 7D can pass. The base 13 supports parallel lift guides T1-T3, which are rods extending vertically. The lift guides T1-T3 can be provided integrally with the base 13.

The linear body 11, which has the shape of a regular triangular prism, has three side faces Z1 to Z3. Racks A1 to A3 are fixed to the side faces Z1 to Z3, respectively. A cavity 12 is formed in the center of the linear body 11, and a bearing U3 (see Figure 7) is disposed in the cavity 12.

Openings V1 to V3 are formed at the three corners of the linear body 11. Lift guides T1 to T3 fixed to the base 13 are inserted into the openings V1 to V3, respectively. Nuts S1 to S3 are attached to the lower ends of the lift guides T1 to T3, respectively.

Figure 14 is an exploded perspective view of the hub 10. The hub 10 comprises a case 21, an outer lid 22, and an inner lid 23. The case 21 comprises a storage section 21A, an opening 21B, hollow sections Q1 to Q3, and openings K1 to K3 (see Figures 4 and 5).

The accommodation section 21A is formed in the center of the case 21, and accommodates the linear body 11 to which the racks A1 to A3 are attached together with the base 13. The accommodation section 21A is, for example, a hollow or recessed section provided in the case 21. The planar shape of the accommodation section 21A corresponds to the planar shape of the base 13, and can be a substantially equilateral triangle. The opening 21B is formed so that the linear body 11 to which the racks A1 to A3 are attached and the base 13 can be placed in the accommodation section 21A through the opening 21B.

The hollow sections Q1 to Q3 are arranged at angular intervals of 120 degrees outside the housing section 21A and communicate with the housing section 21A. The support shaft M1, pinion B1, bearing E1 and shaft adapter D1 are arranged in the hollow section Q1, the support shaft M2, pinion B2, bearing E2 and shaft adapter D2 are arranged in the hollow section Q2, and the support shaft M3, pinion B3, bearing E3 and shaft adapter D3 are arranged in the hollow section Q3. The pinions B1 to B3, bearings E1 to E3 and shaft adapters D1 to D3 can be arranged in these hollow sections Q1 to Q3 through the opening 21B and the housing section 21A.

Openings K1 to K3 are formed on the outer surface of case 21 at angular intervals of 120 degrees, and communicate with hollow portions Q1 to Q3, respectively. Support shafts M1 to M3 can be placed in storage portion 21A by inserting them into openings K1 to K3, respectively.

The inner lid 23 is fixed to the case 21 by a number of bolts J7. Furthermore, the outer lid 22, which covers the inner lid 23, is 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 inner lid 23 has multiple through holes 23A formed in it. The lower ends of the lift guides T1 to T3 (see Figures 12 and 13) are inserted into the through holes 23A of the inner lid 23, respectively, and protrude to the outside of the inner lid 23. On the outside of the inner lid 23, nuts S1 to S3 are attached to the lower ends of the lift guides T1 to T3. This allows the base 13, which is placed in the storage section 21A of the case 21, to be fixed to the upper wall of the case 21.

When the pitch angle change motors 5A and 5B rotate under the above configuration, in the rotation transmission section 6A, the gears G3 and G2 transmit the rotational motion of the pitch angle change motor 5A to the gear G1, and in the rotation transmission section 6B, the gears G3 and G2 transmit the rotational motion of the pitch angle change motor 5B to the gear G1 of the rotary-linear motion conversion section 7 (see Figures 8 to 11). Since the gear G1 is fixed to the ball screw shaft 7F of the rotary-linear motion conversion section 7, the rotational motion of the pitch angle change motors 5A and 5B is transmitted to the ball screw shaft 7F. When the ball screw shaft 7F rotates, the ball screw nut 7G and the linear motion transmission shaft 7D are guided by the linear motion guide section 7E and move linearly in the vertical direction (see Figures 9 to 11).

The linear motion of the linear transmission shaft 7D is transmitted to the linear body 11. In response to the linear motion of the linear transmission shaft 7D, the racks A1 to A3 fixed to the linear body 11 move linearly in the vertical direction together with the linear body 11. When the racks A1 to A3 move linearly together with the linear body 11, the lift guides T1 to T3 guide the linear body 11 (see Figures 12 and 13). The range of movement of the linear body 11 is limited by the base 13 and nuts S1 to S3. The racks A1 to A3 are engaged with pinions B1 to B3, respectively, and when the racks A1 to A3 move linearly, the pinions B1 to B3 fixed to the support shafts M1 to M3 rotate at the same time (see Figures 4 and 5). Therefore, in response to the rotational motion of the pinions B1 to B3, the support shafts M1 to M3 rotate around their respective axes. Grips P1 to P3 that support the rotors H1 to H3 are attached to the support shafts M1 to M3, and the rotational motion of the support shafts M1 to M3 is transmitted to the rotors H1 to H3. Therefore, the pitch angles of the rotors H1 to H3 are changed at the same time. For example, when the linear body 11 is in the position shown in FIG. 12, the pitch angles of the rotors H1 to H3 are set as shown in FIG. 2, and when the linear body 11 is in the position shown in FIG. 13, the pitch angles of the rotors H1 to H3 are set as shown in FIG. 3.

The thrust generating device 1 can change the thrust given to the flying object by changing the rotation angle of the pitch angle changing motors 5A, 5B and thus the pitch angle of the rotors H1 to H3. By changing the thrust by changing the pitch angle, the response speed of the thrust change can be increased and the stability of the flying object can be improved compared to a method of changing the thrust by changing the rotation speed of the thrust generating motor 2. In addition, since the thrust given to the flying object can be changed by changing the pitch angle of the rotors H1 to H3, there is no need to enlarge the rotors H1 to H3, and there is no need to excessively increase the rotation speed of the thrust generating motor 2. Since there is no need to enlarge the rotors H1 to H3, it is possible to suppress the size and weight of the flying object. In addition, since the increase in the rotation speed of the thrust generating motor 2 is suppressed, noise dependent on the rotation speed can be suppressed.

In addition, in the thrust generating device 1, the pitch angle of the rotors H1 to H3 can be changed electrically, eliminating the need to use hydraulics. 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 also facilitating the maintenance and repair of the thrust generating device 1.

In this embodiment, by using a rack and pinion as the motion 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 it is possible to align each of the pinions B1 to B3 concentrically with the support shaft. This allows the arrangement of the three rack and pinions to be compact, and it is possible to house the linear motion rotation conversion unit 8 within the hub 10 while preventing the hub 10 from becoming larger.

In this embodiment, the rotational motion of the two pitch angle change motors 5A, 5B is transmitted to a single gear G1 by the rotational transmission units 6A, 6B, and the rotational-linear motion conversion unit 7 can convert that rotational motion into linear motion of a single linear motion transmission shaft 7D. Therefore, if any of the pitch angle change motors fails, it is possible to change the pitch angle of the rotors H1 to H3 using the rotational motion of the other pitch angle change motor. Therefore, the thrust generating device has high reliability.

The motion mechanism of the rotary-linear conversion unit 7 is constantly connected to the rotation transmission units 6A and 6B, which are connected to the two pitch angle change motors 5A and 5B, respectively. That is, the gear G1 fixed to the ball screw shaft 7F of the rotary-linear conversion unit 7 is constantly meshed with the gear G2 of the rotation transmission units 6A and 6B, and is in a state in which it can rotate with the rotation of the two pitch angle change motors 5A and 5B. Therefore, if one of the pitch angle change motors 5A and 5B fails, the pitch angle of the rotors H1 to H3 can be immediately changed by the other pitch angle change motor 5A and 5B.

When the two pitch angle change motors 5A, 5B are normal, the two pitch angle change motors 5A, 5B may be driven to the same rotation angle. Alternatively, only one of the pitch angle change motors may be driven, and the other pitch angle change motor may be deactivated. In the latter case, the deactivated pitch angle change motor is rotated by the gear G1.

In either case, it is preferable that the pitch angle change motors 5A and 5B are driven by angle control. With angle control, if one of the pitch angle change motors fails, the load power of the other pitch angle change motor is automatically increased, making it possible to configure the control system simply.

In this embodiment, the pitch angle changing motors 5A and 5B are disposed inside the thrust generating motor 2 and fixed to the frame 2C of the thrust generating motor 2. This prevents the thrust generating device 1 from becoming too large.

Although the present invention has been shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that changes in form and detail may be made therein without departing from the scope of the invention as set forth in the appended claims. Such changes, modifications and alterations are intended to be within the scope of the present invention.

For example, in the above embodiment, the number of pitch angle change motors is two, but three or more pitch angle change motors may be provided in the thrust generating device 1, and the rotational motion of these pitch angle change motors may be converted into linear motion of the linear motion transmission shaft 7D.

In the above embodiment, the propeller R is disposed directly below the thrust generating device 1, and the thrust generating device 1 is attached to the bottom of the flying object's body, but the propeller R may be disposed directly above the thrust generating device 1, and the thrust generating device 1 may be attached to the top of the flying object's body.

1 Thrust generating device 2 Thrust generating motor 2A Stator 2B Rotor 2C Frame R Propeller H1 to H3 Rotor P1 to P3 Grip 4 Rotor shaft 5A, 5B Pitch angle changing motor 6 Motion transmission unit 6A, 6B Rotation transmission section 7 Rotation-to-linear conversion section 7D Linear transmission shaft 7F Ball screw shaft 8 Linear-to-rotation conversion section

Claims (2)

a thrust generating motor that rotates a plurality of rotors to generate thrust;
A plurality of pitch angle changing motors for changing the pitch angle of the rotor blades;
a plurality of rotation transmission units respectively connected to the plurality of pitch angle changing motors;
a first motion conversion unit having a single linear motion shaft and a motion conversion mechanism, the motion conversion mechanism being connectable to the plurality of rotation transmission units and the linear motion shaft, and converting rotation of at least one of the rotation transmission units into linear motion of the linear motion shaft;
a second motion conversion unit that converts the linear motion of the linear motion shaft into rotational motion to change the pitch angle of the rotor ,
13. A thrust generating apparatus , comprising: a pitch angle changing motor arranged inside the thrust generating motor and fixed to a stationary member of the thrust generating motor . 2. The thrust generating device according to claim 1, wherein the motion conversion mechanism of the first motion conversion unit is constantly connected to the plurality of rotation transmission units and is capable of converting rotations of the plurality of rotation transmission units into linear motion of the linear motion shaft.

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