Electric helicopter drive device, electric helicopter, and method for manufacturing rolling bearing used therein

Abstract

To provide an electric helicopter driven by two lightweight and simple-structured motors, in which magnetic force of an unused motor is eliminated to reduce resistance to rotation of rotor blades.SOLUTION: A helicopter drive device is mounted on an upper portion of a helicopter body, supports an electric motor and rotor blades with a pair of bearings and has two motors operating with separate electric circuits vertically. In an electric helicopter equipped with this drive device, an inner race of a sliding bearing or rolling bearing is sandwiched by an outer race, a stator is provided on the outer race, and a rotor is provided on the inner race. The stator coils of the driving motor are provided in two upper and lower stages, and the rotor field coils are also provided in two upper and lower stages, and electric circuits are also provided in two upper and lower circuits. During ascent, the helicopter is driven by both upper and lower motors. During cruising flight, the helicopter flies using only one motor. Electricity to the field coil of one motor in which a malfunction occurs is cut off to eliminate the magnetic force of the rotor, allowing the helicopter to continue flying and landing with the remaining motor, thereby improving safety.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an electric helicopter drive device, an electric helicopter, and a method for manufacturing a rolling bearing used therein, and more particularly to a drive device that improves safety in an emergency that occurs during flight of an electric helicopter. [Background technology]

[0002] Today, motor control technology and route control technology for electrically powered helicopters are being developed, but there is a need for a lightweight two-motor technology that provides increased safety and can respond to emergencies caused by motor or electrical malfunctions.

[0003] A helicopter can descend and land as long as its rotors are rotating, so to achieve this, an electric helicopter needs a motor with large diameter rotors that can be manually adjusted to adjust the pitch, allowing it to descend safely in an emergency, and that can follow and rotate without resistance.

[0004] Conventional electric helicopter motors use permanent magnets in the rotor, so during autorotation the magnetic force suppresses the rotor's rotation, creating resistance to the rotation of the rotor blades, so a clutch is provided to disconnect it. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 7366946 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention focuses on the above-mentioned problems and aims to provide a lightweight, simple-structure, two-motor electric helicopter that eliminates the magnetic force of unused motors to reduce the rotational resistance of the rotor blades. [Means for solving the problem]

[0007] In order to achieve the above object, the drive device for an electric helicopter according to the present invention is characterized by having an electric motor mounted on the top of the helicopter body and a set of bearings that support the rotors, and the electric motor is equipped with two sets of motors, one above the other and one below, that are driven by separate electric circuits.

[0008] Furthermore, the electric helicopter of the present invention has a rotor attached to the top of the inner race of the bearing that supports the electric motor and rotor blades that drive the electric helicopter, a stator attached to the top of the outer race that mounts the drive unit on the helicopter, the stator coils arranged in two tiers, upper and lower, the rotor field coils also arranged in two tiers, upper and lower, and separate electrical circuits for the top and bottom, and is driven by the two motors when the helicopter rises, and flies using only one motor during cruising flight, and if a problem occurs in either motor, the electricity to the field coil is cut off to eliminate the magnetic force of the rotor, and the helicopter flies and lands using the remaining motor.

[0009] In addition, this configuration is characterized in that a sliding bearing or a rolling bearing is provided in a portion that supports the rotation of the helicopter rotor. The present invention is characterized by the use of sliding or rolling bearings in the bearings that support the electric motor and rotor that drive the electric helicopter, a rotor with multiple sets of field coils with separate electrical circuits attached to the top and bottom of the inner race that makes up the bearing, a stator with multiple sets of coils with separate electrical circuits attached to the top and bottom of the outer race, and a slip ring that supplies power to the field coils at the top of the lift guide used for variable pitch that is located in the center of the rotor, so that if a problem occurs with one of the motors, the helicopter can fly using the other motor, and if both motors fail, the helicopter can descend and land by autorotation.

[0010] In addition, the rotor bearings that support the helicopter's electric motor and rotor blades are made by kneading a light-weight fireproof material, shaping it into a spherical shape, embedding iron rivets into the surface of the balls, and then covering the sintered fireproof material with molten steel to create thick, spherical balls, which are used as rolling elements, resulting in a lighter weight and a larger diameter ball that reduces the rotation speed. [Effects of the Invention]

[0011] With the above configuration, the rotor equipped with a field coil loses its magnetic force when electricity is cut off, and when idling it rotates smoothly without any load, so it does not put a burden on the other motor and reduces battery consumption, and the structure that electrically separates the two motors is highly safe.

[0012] In the worst case scenario, even if two motors or electrical circuits malfunction, the shifter arm can be manually operated to adjust the pitch, allowing the drone to descend and land by autorotation in an emergency. The main electric motor and rotor are directly connected and driven, which makes for a quiet drive system that uses fewer parts and maintains safety. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is an overall view of an electric helicopter according to an embodiment, seen from above. [Figure 2] 1 is a perspective view, partially in section, of a drive device according to a first embodiment. [Figure 3] 1 is a partial cross-sectional side view of a drive device according to a first embodiment. [Figure 4] FIG. 10 is a partial cross-sectional side view of a drive device according to a second embodiment. [Figure 5] FIG. 10 is a cross-sectional view of an assembly insertion port for the rolling bearing ball according to the second embodiment. [Figure 6] FIG. 1 is an overall side view of an electric helicopter according to an embodiment. [Figure 7] FIG. 10 is a plan view of a ball formed by kneading a refractory material, which is the base of the ball of the rolling bearing according to the second embodiment. [Figure 8] FIG. 10 is a plan view of a refractory material ball with a rivet embedded therein according to a second embodiment. [Figure 9] 10 is a cross-sectional elevation view of the manufacturing process of firing the ball and covering it with molten steel according to a second embodiment. FIG. [Figure 10] FIG. 10 is a cross-sectional view of a ball of a rolling bearing according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] The drive device for an electric helicopter according to the present invention will be described in detail below. The illustrated example is merely one embodiment, and other modifications are included as long as the technical concept is the same.

[0015] A drive device for an electric helicopter according to a first embodiment is shown in FIGS. 1 to 3. FIG.

[0016] An overview of an electric helicopter 10 according to the first embodiment is shown in Figure 1. The electric helicopter 10 has a cabin 12 mounted on a body frame 14 at the front. The body frame 14 is also provided with a tail frame 16 extending rearward, with a tail rotor 18 at the tip of the tail frame 16. The body frame 14 has side frames 14A that extend from the outer side of the cabin 12 to the top, and an electric motor 22 that constitutes a main rotor 20 that serves as a drive device is installed at the top.

[0017] First, the main rotor 20 is a cylindrical shaft mounted at the upper end of the cabin 12. An inner race 26, which acts as a flange-like protrusion, is mounted on the outside of the lower end of the shaft, and the outer race 24 is mounted so as to sandwich the inner race 26 from above and below in a U-shape. The outer peripheral end of the outer race 24 is mounted on the frame 14C above the cabin 12, so that the inner race 26 can rotate while the outer race 24 is fixed. A resin metal 28 is interposed between the U-shaped portion of the outer race 24 and the inner race 26, allowing the outer race 24 to rotate smoothly. As a result, the sliding portion between the outer race 24 and the inner race 26 forms a plain bearing.

[0018] The outer peripheral end of the outer race 24 is placed on the frame 14C above the cabin 12, and pedestals 30 are arranged at four equiangular positions on the top of the rotor 29 mounted on the upper part of the inner race 26. The base of a long rotor 32 is rotatably supported on each of the pedestals 30 via a metal cap 30A, so that the inner race 26, rotor 29, pedestal 30, and rotor 32 are directly connected and can rotate integrally, using the outer race 24 as a guide. In this configuration, two sets of electric motors 22, one above the other, are provided to rotate the rotor 32.

[0019] The electric motor 22 of this drive device has a stator 34 mounted on the outer race 24 and two sets of coils 5A, 5B with separate upper and lower electrical circuits, and a rotor 29 mounted on the inner race 26 and two sets of field coils 6A, 6B with separate upper and lower electrical circuits.

[0020] Magnetic buffer material 7 is provided between upper and lower coils 5A and 5B provided on stator 34 and between upper and lower field coils 6A and 6B provided on rotor 29, so that the magnetic force between the upper and lower coils does not affect each other.

[0021] A variable pitch mechanism 42 is disposed in a central space 40 surrounded by the rotor 29. The variable pitch mechanism 42 has pitch change end plates 44 attached to the base end surfaces of the rotor blades 32, and the pitch of the rotor blades 32 is changed by vertically driving the pitch change end plates 44. To vertically drive the pitch change end plates 44, an elevation guide 48 is erected at the center of the upper frame 14C of the outer frame connected to the side frames 14A, and a shifter sleeve 50 is fitted into this so that it can be raised and lowered. The shifter sleeve 50 is connected via a connecting tongue 54 to a rod 52 that communicates with the pitch change end plates 44 attached to the base ends of the rotor blades 32. Therefore, the pitch of the rotor blades 32 can be changed by vertically moving the shifter sleeve 50.

[0022] As shown in Figures 2 and 3, a slip ring 82 that supplies power to the field coils 6A and 6B of the rotor 29 is provided at the top of the lift guide 48, which moves up and down and is located in the center of the rotor 29, and sends electricity when necessary.

[0023] A shifter arm 56 is disposed perpendicular to the upright shifter sleeve 50 below it. One end of the shifter arm 56 is pivotally attached to a circumferential retaining wall 14D formed on the upper frame 14C, and the other end is threadedly attached to a ball screw 58 erected on the upper frame 14C. By rotating the ball screw 58, the shifter arm 56 can move up and down from the pivot point. A shifter ring 62 having an annular groove 60 at its lower end is provided on the shifter sleeve 50, and the shifter arm 56 intersects with the annular groove 60. A slider 64 that fits into the annular groove 60 of the shifter ring 62 is provided on the shifter arm 56. As the shifter arm 56 moves up and down, the shifter sleeve 50 moves up and down along the lift guide 48, thereby changing the pitch of the rotor 32.

[0024] A variable pitch motor 66 for driving the ball screw 58 is attached to the underside of the upper frame 14C, and a manual handle 68 is provided for manually operating the ball screw 58. Therefore, the pitch of the rotor 32 is normally controlled by the variable pitch motor 66, but can be controlled by the manual handle 68 in an emergency.

[0025] Circumferential retaining wall 14D is formed concentrically with ring frame 14B, and two sets of coils 5A, 5B are mounted on top of stator 34, which is provided on the top of outer race 24. Two sets of field coils 6A, 6B are arranged on rotor 29 facing these, and are surrounded and protected by bottom plate 27 that extends to the underside of stator 34. A waterproof cover 70 is provided on the upper half of inner race 26 to protect the upper end of circumferential retaining wall 14D from rainwater, and a vibration prevention member 72 is provided inside rotor 29 to prevent vibration of shifter sleeve 50.

[0026] 1 and 6, legs 74 are provided at the bottom of the electric helicopter 10 to support the helicopter body during takeoff and landing. A plurality of batteries 75 are provided on the underside of the body frame 14 to support the drive of the power supply system. An electric helicopter configured in this way is powered by both the upper and lower motors during ascent, landing, and strong winds, and flies on only one motor during cruising flight; at this time, the electricity to the other motor is cut off and the magnetic force of the field coil disappears, so there is no burden on the operating motor.

[0027] With the above configuration, the rotor equipped with a field coil loses its magnetic force when electricity is cut off, and it rotates smoothly without load when idling, so it does not put a burden on the other motor and reduces battery consumption, and the structure that electrically separates the two motors is highly safe.

[0028] In addition, even in the worst case scenario where a malfunction occurs in the two motors or electrical circuits, the shifter arm can be manually operated to adjust the pitch, allowing the drone to descend and land by autorotation in an emergency.

[0029] The main electric motor and rotor are directly connected and driven, resulting in a drive unit that generates little noise, reduces the number of parts used, and maintains safety.

[0030] Next, a second embodiment will be described. Figures 4 to 10 show this example, in which an electric motor is provided above the rolling bearing. A rotor 29 is provided above the inner race 79 of the rolling bearing, and an outer race 78 is provided on a receiving seat 81, with a stator 34 provided above. A base 30 that supports the rotor 32 is provided above the rotor 29, and a variable pitch mechanism 42 is provided at the end of the rotor 32, and the force of the shifter sleeve 50 moving up and down is transmitted by a rod 52, thereby achieving variable pitch.

[0031] In this way, the electric helicopter 10 can be driven by the rotation of the rotor 29 through the rolling bearing 76 as well. As a method for lightening the balls of the rolling bearing 76 of the drive unit, as shown in Figures 7 to 10, the refractory material that forms the base of the rolling bearing 76 is kneaded to form a spherical ball 77, which is then sintered with rivets 84 embedded in the entire surface of the ball 85, which is then placed on a surface plate 86 and sandwiched between rolling plates 87, and molten steel 88 is then applied to form a spherical ball 85, resulting in a lightweight rolling bearing 76.Assembling the rolling bearing 76 is done through an inlet 89 as shown in Figure 5, allowing the balls to be inspected, and the drive unit is supported by rolling bearings 76 that use large diameter balls and have a reduced rotation speed. [Explanation of symbols]

[0032] 5A, 5B... Coil, 6A, 6B... Field coil, 7... Magnetic buffer material, 10... Electric helicopter, 12... Cabin, 14... Body frame, 14A... Side frame, 14B... Ring frame, 14C... Upper frame, 14D... Circumferential retaining wall, 16... Tail frame, 18... Tail rotor, 20... Main rotor, 22... Electric motor, 24... Outer race, 26... Inner race, 27... Bottom plate, 28... Resin metal, 29... Rotor, 30... Base, 30A... Metal cap, 32... Rotor, 34... Stator, 40... Central space, 42... Variable pitch mechanism, 44... Pitch change end plate, 4 8...lifting guide, 50...shifter sleeve, 52...rod, 54...connecting tongue, 56...shifter arm, 58...ball screw, 60...annular groove, 62...shifter ring, 64...slider, 66...variable pitch motor, 68...handle, 70...waterproof cover, 72...anti-vibration member, 74...leg, 75...battery, 76...rolling bearing, 77...ball, 78...outer race, 79...inner race, 81...receiving seat, 82...slip ring, 83...field cable, 84...rivet, 85...ball, 86...surface plate, 87...rolling plate, 88...molten steel, 89...feed port.

Claims

1. A drive device for an electric helicopter is provided with a set of bearings that support the electric motor and rotors mounted on the top of the helicopter body, and the electric motor is provided with two sets of motors, one above the other, that are driven by separate electric circuits.

2. This electric helicopter is characterized by the fact that a rotor is attached to the top of the inner race of the bearing that supports the electric motor and rotor blades that drives the electric helicopter, a stator is provided on top of the outer race that mounts the drive unit on the helicopter, the coils of the stator are provided in two tiers, one above the other, and the field coils of the rotor are also provided in two tiers, one above the other, with separate electrical circuits for the top and the bottom; when the helicopter rises, it is driven by the two motors, the top and the bottom, and during cruising flight it flies using only one motor; if a problem occurs in either motor, the electricity to the field coil is cut off to eliminate the magnetism of the rotor, and the helicopter flies and lands using the remaining motor.

3. 3. The electric helicopter according to claim 2, wherein a sliding bearing is provided in a portion that supports the rotation of the rotor of the helicopter.

4. 3. The electric helicopter according to claim 2, wherein a rolling bearing is provided in a portion that supports the rotation of the rotor of the helicopter.

5. An electric helicopter characterized in that sliding or rolling bearings are provided for the bearings that support the electric motor and rotor that drive the electric helicopter, a rotor with multiple sets of field coils with separate electrical circuits attached to the top and bottom of the inner race that constitutes the bearing is provided on the top of the inner race, a stator with multiple sets of coils with separate electrical circuits attached to the top and bottom of the outer race is provided on the top of the outer race, and a slip ring that supplies power to the field coils is provided on the top of an elevation guide used for variable pitch that is provided in the center of the rotor, so that if a problem occurs with one of the motors, the helicopter can fly using the other motor, and if both motors fail, the helicopter can descend and land by autorotation.

6. This bearing manufacturing method is characterized by using a rolling element for a rotor bearing that supports a helicopter's electric motor and rotor blades, in which a ball made by kneading a refractory material with a light specific gravity, shaping it into a spherical shape, embedding iron rivets on the surface of the ball, and covering the refractory material with molten steel to form a thick, spherical shape, as a rolling element, thereby reducing weight and suppressing the number of rotations with a large diameter ball.

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