Electric variable pitch airscrew

Abstract

This invention discloses an electric variable-pitch aircraft propeller, comprising: a hub, blades, a pitch control rod, a first linear motor, and a first linear motor control mechanism; the blades are rotatably connected to the hub; the pitch control rod is axially disposed within the hub and drives the propeller to change pitch through axial movement; the output end of the first linear motor is connected to the pitch control rod and is used to drive the pitch control rod to move axially; a limit switch is provided in the circuit system of the first linear motor; the first linear motor control mechanism is used to control the limit switch. The electric variable-pitch aircraft propeller of this invention uses electric power to drive pitch change, resulting in fast pitch change time; no lubricating oil corrosion; no need for a speed governor; compact structure; safe and reliable; simple maintenance; and low operating cost.

Description

Technical Field

[0001] This invention belongs to the field of aviation propeller technology, specifically relating to an electric variable pitch aviation propeller. Background Technology

[0002] The purpose of variable pitch aircraft propellers is to maintain a suitable angle of attack within a certain range, so that the propeller has high working efficiency and the engine speed remains stable.

[0003] Traditional aircraft propellers primarily rely on lubricating oil pressure to change pitch. For example... Figure 1 As shown, a hydraulic cylinder 11' (located inside the fairing 5) is installed at the front end of the hub 2 of a conventional propeller. By utilizing the continuous supply of lubricating oil from the engine 4 and adjusting the supply of lubricating oil 10' through the governor 12', the pressure of the propeller's pitch-changing lubricating oil is controlled, and ultimately the pitch angle is controlled.

[0004] Furthermore, such as Figure 2 As shown, the cylinder 11' contains a piston 111', which can drive the pitch control rod 6 (this conventional pitch control rod 6 has a lubricating oil channel 60' in the center) to move, thereby realizing the pitch change of the propeller. One side of the piston 111' (i.e....) Figure 2 The left side of the piston is filled with lubricating oil, and the other side is equipped with a spring. When the lubricating oil supply increases, the lubricating oil pushes the piston 111' to the right, thereby causing the pitch rod 6 to move to the right, and the propeller begins to change pitch; conversely, when the lubricating oil supply decreases, the lubricating oil pressure is insufficient to counteract the spring, so the piston 111' moves to the left, and the propeller begins to return to the initial pitch position.

[0005] This method of using lubricating oil pressure to change pitch has the following problems:

[0006] (1) Slow response time for variable pitch;

[0007] (2) Deteriorated lubricating oil will corrode the propeller (the lubricating oil will deteriorate if it is used for too long);

[0008] (3) The output of lubricating oil is controlled by a speed governor, which is not accurate enough. Moreover, the speed governor is connected to the cockpit handle by a steel cable, which is unreliable and prone to failures such as steel cable jamming and wear.

[0009] (4) There is lubricating oil flowing in the cylinder, and the center of gravity changes at any time, which will cause the propeller to be unbalanced. If the high-speed rotating propeller is unbalanced, it will affect the engine and fuselage structure, and even cause resonance. Summary of the Invention

[0010] To address the aforementioned problems, this invention provides an electric variable-pitch aircraft propeller that uses electric power to drive the variable pitch and can be used for the electrification of traditional fuel engine propellers.

[0011] This invention provides an electric variable-pitch aircraft propeller, comprising: a hub, blades, a pitch control rod, a first linear motor, and a first linear motor control mechanism; the blades are rotatably connected to the hub; the pitch control rod is axially disposed within the hub and drives the propeller to change pitch through axial movement; the output end of the first linear motor is connected to the pitch control rod and is used to drive the pitch control rod to move axially; a limit switch is provided in the circuit system of the first linear motor; the first linear motor control mechanism is used to control the limit switch.

[0012] In one embodiment of the present invention, the propeller hub is rotatably mounted on the output end of the engine; a brush is provided at one end of the engine near the propeller hub; a conductive ring is provided around the propeller hub, the conductive ring being located on the side of the propeller hub near the engine and in contact with the brush.

[0013] In one embodiment of the present invention, the first linear motor control mechanism includes: a second linear motor, a spring, a switch control rod, and a limit guide; the output end of the second linear motor is connected to one end of the spring; the other end of the spring is connected to the switch control rod; the switch control rod passes through the limit guide and controls the limit switch by axial movement.

[0014] In one embodiment of the present invention, the second linear motor is electrically connected to the control system and is used to operate according to the instructions issued by the control system.

[0015] In one embodiment of the present invention, the first linear motor control mechanism further includes a centrifugal flyweight assembly; the centrifugal flyweight assembly includes a flyweight and a flyweight base; a pin is provided on the flyweight base; the flyweight includes a centrifugal part and a working part, the centrifugal part and the working part are connected at an angle, and a pin hole is provided at the connection between the centrifugal part and the working part; the flyweight is rotatably connected to the pin through the pin hole; the working part contacts the switch control lever, and when the flyweight rotates around the pin in the direction from the working part to the centrifugal part, the working part can push the switch control lever to compress the spring.

[0016] In one embodiment of the present invention, the switch control lever includes an input portion, an output portion, and a connecting portion located between the input portion and the output portion; the cross-sectional area of ​​the connecting portion is smaller than the cross-sectional area of ​​the input portion, the connecting portion passes through the limiting guide, and the input portion and the output portion are respectively located on both sides of the limiting guide; the side of the input portion away from the connecting portion is connected to a spring, and the working part of the flyweight abuts against the side of the input portion away from the spring; the output portion is used to control the limit switch.

[0017] In one embodiment of the present invention, the circuit system of the first linear motor is further provided with a contactor; and / or, the circuit system of the first linear motor is further provided with a direct control switch, the direct control switch being connected to the control system via an electrical signal and used to open and close according to the instructions issued by the control system.

[0018] In one embodiment of the present invention, the limit switch includes a first limit switch, a second limit switch, a third limit switch, and a fourth limit switch; when the switch control lever is located in a first preset position, the switch control lever compresses the first limit switch and the fourth limit switch, causing the normally open contacts of the first limit switch and the normally closed contacts of the fourth limit switch to close and open; when the switch control lever is located in a second preset position, the switch control lever compresses the second limit switch and the third limit switch, causing the normally open contacts of the second limit switch and the normally closed contacts of the third limit switch to close and open.

[0019] In one embodiment of the present invention, the contactor includes a first contactor, a second contactor, and a third contactor; in the circuit system of the first linear motor: the first terminal of the power supply is connected to the first terminal of the first branch, the first terminal of the second branch, the first terminal of the third branch, the first terminal of the fourth branch, and the first terminal of the fifth branch; the second terminal of the power supply is connected to the second terminal of the first branch, the second terminal of the second branch, the second terminal of the third branch, the second terminal of the fourth branch, and the second terminal of the fifth branch; the first branch is connected in series with the normally closed contact of the first limit switch, the normally closed contact of the third contactor, the first normally closed contact of the third limit switch, the first normally closed contact of the second contactor, and the coil of the first contactor, wherein the normally closed contact of the first limit switch is also connected in parallel with the first normally open contact of the first contactor; the second branch is connected in series with the normally closed contact of the second limit switch, the first normally open contact of the third contactor, the first normally closed contact of the fourth limit switch, the first normally closed contact of the first contactor, and the coil of the second contactor. The coil, wherein the normally closed contact of the second limit switch and the first normally open contact of the third contactor are also connected in parallel with the first normally open contact of the second contactor; the third branch is connected in series with the second normally closed contact of the fourth limit switch, the second normally open contact of the third contactor, and the coil of the third contactor, wherein the second normally closed contact of the fourth limit switch and the second normally open contact of the third contactor are also connected in parallel with the normally open contact of the third limit switch; the fourth branch and the fifth branch are both connected to the first linear motor, wherein the first end of the first linear motor is connected to the first end of the fourth branch through the second normally open contact of the first contactor, and the second end of the first linear motor is connected to the second end of the fourth branch through the third normally open contact of the first contactor; the first end of the first linear motor is also connected to the second end of the fifth branch through the third normally open contact of the second contactor, and the second end of the first linear motor is also connected to the first end of the fifth branch through the second normally open contact of the second contactor.

[0020] In one embodiment of the present invention, the direct control switch includes a first direct control switch and a second direct control switch; the first terminal of the power supply is also connected to the first terminal of the sixth branch and the first terminal of the seventh branch, and the second terminal of the power supply is also connected to the second terminal of the sixth branch and the second terminal of the seventh branch; the sixth branch is connected in series with the first direct control switch, the second normally closed contact of the third limit switch, the second normally closed contact of the second contactor, and the coil of the first contactor, wherein the first direct control switch is also connected in parallel with the fourth normally open contact of the first contactor; the seventh branch is connected in series with the second direct control switch, the third normally closed contact of the fourth limit switch, the second normally closed contact of the first contactor, and the coil of the second contactor, wherein the second direct control switch is also connected in parallel with the fourth normally open contact of the second contactor.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) The present invention adopts electric drive for pitch change, which has a fast pitch change time; there is no lubricating oil corrosion; no speed governor is needed; the structure is compact, safe and reliable, simple to maintain, and low operating cost; there is no liquid flow, which is conducive to propeller balance.

[0023] (2) This invention can be applied to electric aircraft or eVTOL (vertical takeoff and landing aircraft), and can also be used for the electrification of traditional fuel engine propellers. Since it does not require major modifications to the pitch control mechanism inside the traditional propeller hub, only the hydraulic cylinder at the front end needs to be replaced with an electric motor, the pitch control rod needs to be slightly modified to connect with the motor, and conductive ring brush assemblies need to be added to the propeller and engine to complete the modification. Moreover, it is easy to implement and facilitates the transition from lubricated pitch control to electric pitch control.

[0024] (3) The electric variable pitch propeller of the present invention is more convenient to cooperate with the intelligent management system in the cockpit, making the propeller pitch change intelligent. Compared with the traditional manual handle control, the electric variable pitch propeller is more efficient, economical and safe under the control of the intelligent management system.

[0025] (4) The present invention controls the operation of the first linear motor through the first linear motor control mechanism, thereby controlling the pitch change, so that the speed of the propeller is always in a dynamic equilibrium state. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of a traditional aircraft propeller in the background art;

[0027] Figure 2 for Figure 1 Internal structural diagram of the middle section;

[0028] Figure 3 This is a schematic diagram of the structure of the electric variable-pitch aircraft propeller in Embodiment 1 of the present invention;

[0029] Figure 4 for Figure 3 Schematic diagram of the structure of the switch control lever of Zhongfei Heavy Machinery;

[0030] Figure 5 This is a schematic diagram of the position of the switch control lever in Embodiment 1 of the present invention, where a is a schematic diagram of the switch control lever in the first preset position and b is a schematic diagram of the switch control lever in the second preset position;

[0031] Figure 6 This is a schematic diagram showing the positional relationship between the conductive ring and the propeller hub in Embodiment 1 of the present invention;

[0032] Figure 7 This is a schematic diagram of the circuit system of the first linear motor in Embodiment 1 of the present invention.

[0033] 10'-Lubricating oil, 11'-Oil cylinder, 111'-Piston, 12'-Governor, 60'-Lubricating oil passage;

[0034] 1-First linear motor, 10-Circuit system of the first linear motor, 2-Buzzer, 3-Blade, 4-Engine, 5-Fairing, 6-Pitch rod, 7-Conductive ring, 8-Brush, 9-Control mechanism of the first linear motor, 91-Switch control rod, 910-Limit guide, 911-Input part, 912-Connecting part, 913-Output part, 92-Second linear motor, 93-Spring, 94-Fly weight seat, 95-Fly weight, 951-Centrifugal part, 952-Working part, 96-Pin shaft;

[0035] 100 - Power supply, 101 - First branch, 102 - Second branch, 103 - Third branch, 104 - Fourth branch, 105 - Fifth branch, 106 - Sixth branch, 107 - Seventh branch, 108 - First direct control switch, 109 - Second direct control switch, SQ1-b - Normally closed contact of the first limit switch, SQ2-b - Normally closed contact of the second limit switch, SQ3-1b - First normally closed contact of the third limit switch SQ3-2b - Second normally closed contact of the third limit switch; SQ3-k - Normally open contact of the third limit switch; SQ4-1b - First normally closed contact of the fourth limit switch; SQ4-2b - Second normally closed contact of the fourth limit switch; SQ4-3b - Third normally closed contact of the fourth limit switch; KM1-0 - Coil of the first contactor; KM1-1b - First normally closed contact of the first contactor; KM1-2b - First contactor coil. The second normally closed contact of the contactor, KM1-1k - the first normally open contact of the first contactor, KM1-2k - the second normally open contact of the first contactor, KM1-3k - the third normally open contact of the first contactor, KM1-4k - the fourth normally open contact of the first contactor, KM2-0 - the coil of the second contactor, KM2-1b - the first normally closed contact of the second contactor, KM2-2b - the second normally closed contact of the second contactor, KM2-1k - the first normally open contact of the second contactor, KM2-2k - the second normally open contact of the second contactor, KM2-3k - the third normally open contact of the second contactor, KM2-4k - the fourth normally open contact of the second contactor, KM3-0 - the coil of the third contactor, KM3-b - the normally closed contact of the third contactor, KM3-1k - the first normally open contact of the third contactor, KM3-2k - the second normally open contact of the third contactor. Detailed Implementation

[0036] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Example 1

[0038] This embodiment provides an electric variable pitch aircraft propeller, including a hub 2, blades 3, a pitch control rod 6, a first linear motor 1, and a first linear motor control mechanism 9.

[0039] The blade 3 is rotatably connected to the hub 2; the pitch control rod 6 is arranged axially within the hub 2, and drives the propeller to change pitch through axial movement. The method by which the axial movement of the pitch control rod 6 drives the propeller to change pitch can be achieved using existing technologies, and will not be elaborated further here.

[0040] The propeller hub 2 is rotatably mounted on the output end of the engine 4. A brush 8 is provided at one end of the engine 4 near the propeller hub 2. A conductive ring 7 is fitted over the propeller hub 2, located on the side of the propeller hub 2 closest to the engine 4 and in contact with the brush 8. Since the propeller hub 2 and the engine 4 are rotatably connected, it is inconvenient to introduce electricity to the various electrical devices located on the propeller hub 2 via wires. Therefore, a conductive ring 7 is provided on the propeller hub 2, and a brush 8 is provided on the engine 4. Even if the conductive ring 7 rotates and the brush 8 does not rotate, as long as the conductive ring 7 and the brush 8 remain in contact, electricity can be introduced into the conductive ring 7. The conductive ring 7 is then electrically connected to each electrical device to supply power to that device. The propeller hub 2 is generally assembled from a front half and a rear half, connected by a clamping screw. In this embodiment, the conductive ring 7 can be mounted on the clamping screw, or it can be located in other positions.

[0041] The output end of the first linear motor 1 is connected to the pitch control rod 6, and is used to drive the pitch control rod 6 to move axially. The circuit system 10 of the first linear motor is equipped with a limit switch; the first linear motor control mechanism 9 is used to control the limit switch.

[0042] In this embodiment, as a preferred solution, the first linear motor control mechanism 9 includes: a second linear motor 92, a spring 93, a switch control rod 91, a limit guide 910, and a centrifugal flyweight assembly.

[0043] The second linear motor 92 is connected to the control system via electrical signals and is used to operate according to the instructions issued by the control system. The output end of the second linear motor 92 is connected to one end of the spring 93. The spring 93 is a compression spring. When the second linear motor 92 is working, the degree of compression of the spring 93 can be controlled. For example, when the output end of the second linear motor 92 extends, the spring 93 can be compressed.

[0044] The other end of the spring 93 is connected to the switch control lever 91; the switch control lever 91 passes through the limiting guide 910 and controls the limit switch by axial movement. The limiting guide 910 can be a baffle with a guide hole for the switch control lever 91 to pass through, or it can be several blocks arranged in a ring to form a guide channel for the switch control lever 91 to pass through. In addition to guiding the switch control lever 91, the limiting guide 910 can also limit the range of movement of the switch control lever 91, that is, it can limit the movement of the switch control lever 91.

[0045] The switch control lever 91 includes an input portion 911, an output portion 913, and a connecting portion 912 located between the input portion 911 and the output portion 913. The cross-sectional area of ​​the connecting portion 912 is smaller than the cross-sectional areas of the input portion 911 and the output portion 913, making the switch control lever 91 I-shaped. The connecting portion 912 passes through a limiting guide 910, and the input portion and the output portion are located on both sides of the limiting guide 910. The side of the input portion 911 away from the connecting portion 912 is connected to a spring 93, and the output portion 913 is used to control the limit switch.

[0046] The centrifugal weight assembly includes a weight 95 and a weight base 94; the weight base 94 is provided with a pin 96; the weight 95 includes a centrifugal part 951 and a working part 952, the centrifugal part 951 and the working part 952 are connected at an angle, and a pin hole is provided at the connection between the centrifugal part 951 and the working part 952; the weight 95 is rotatably connected to the pin 96 through the pin hole; the working part 952 contacts the switch control lever 91, preferably abutting against the side of the input part 911 of the switch control lever 91 away from the spring 93; when the weight 95 rotates around the pin 96 in the direction from the working part 952 to the centrifugal part 951, the working part 952 can push the switch control lever 91 to compress the spring 93.

[0047] In other words, the working part 952 of the propeller 95 is located between the input part 911 of the switch control lever 91 and the limiting guide 910. When the propeller starts to rotate or the speed increases, the propeller 95 rotates around the pin 96 due to centrifugal force. The end of the working part 952 away from the pin 96 tilts up, pushing the input part 911 of the switch control lever 91 towards the compression spring 93. The output part 913 of the switch control lever 91 also moves towards the compression spring 93. Figure 5 The process from a to b; similarly, when the propeller speed decreases or stops rotating, the flyweight 95 rotates in the opposite direction, the raised end of the working part 952 begins to return to its original position, the input part 911 of the switch control lever 91 moves away from the spring 93 under the pressure of the spring 93, and the output part 913 also moves away from the spring 93, as... Figure 5 The process from b to a. The limit switch can be controlled by moving the output unit 913.

[0048] The limit switch includes a first limit switch, a second limit switch, a third limit switch, and a fourth limit switch. When the switch control lever 91 is in a first preset position, the switch control lever 91 compresses the first and fourth limit switches, causing the normally open contacts of the first and fourth limit switches to close and the normally closed contacts to open. When the switch control lever 91 is in a second preset position, the switch control lever 91 compresses the second and third limit switches, causing the normally open contacts SQ3-k of the second and third limit switches to close and the normally closed contacts to open. In this embodiment, as a preferred solution, the first preset position is defined as the position where the switch control lever 91 is moved to its maximum distance away from the spring 93, i.e., when the output part 913 is furthest from the limit guide 910. Figure 5 The state shown in Figure a; when the switch control member 91 is moved to the maximum distance in the direction of the compression spring 93, that is, when the output part 913 is closest to the limit guide member 910, is taken as the second preset position, such as Figure 5 The state is shown in b. The switch control lever 91 can move axially between the first preset position and the second preset position. When the switch control lever 91 is between the first preset position and the second preset position (but has not reached the first preset position or the second preset position), the switch control lever 91 has no effect on the limit switches, and the limit switches are in their original state (that is, the normally closed contacts of the first limit switch, the second limit switch, the third limit switch, and the fourth limit switch are all closed, and the normally open contacts are all open).

[0049] The circuit system of the first linear motor 1 is also equipped with contactors to achieve electrical interlocking. In this embodiment, the contactors include a first contactor, a second contactor, and a third contactor.

[0050] The circuit system of the first linear motor 1 also includes a direct control switch, which is connected to the control system via electrical signals and is used to open and close according to the instructions issued by the control system. In this embodiment, the direct control switch includes a first direct control switch 108 and a second direct control switch 109.

[0051] In this embodiment, the specific connection relationship of the circuit system of the first linear motor 1 is as follows:

[0052] Power supply 100 is electrically connected to conductive ring 7 and is used to supply power to the entire circuit system;

[0053] The first end of the power supply 100 is connected to the first end of the first branch 101, the first end of the second branch 102, the first end of the third branch 103, the first end of the fourth branch 104, and the first end of the fifth branch 105.

[0054] The second terminal of power supply 100 is connected to the second terminal of the first branch 101, the second terminal of the second branch 102, the second terminal of the third branch 103, the second terminal of the fourth branch 104, and the second terminal of the fifth branch 105;

[0055] The first branch 101 is connected in series with the normally closed contact SQ1-b of the first limit switch, the normally closed contact KM3-b of the third contactor, the first normally closed contact SQ3-1b of the third limit switch, the first normally closed contact KM2-1b of the second contactor, and the coil KM1-0 of the first contactor. The normally closed contact SQ1-b of the first limit switch is also connected in parallel with the first normally open contact KM1-1k of the first contactor.

[0056] The second branch 102 is connected in series with the normally closed contact SQ2-b of the second limit switch, the first normally open contact KM3-1k of the third contactor, the first normally closed contact SQ4-1b of the fourth limit switch, the first normally closed contact KM1-1b of the first contactor, and the coil KM2-0 of the second contactor. The normally closed contact SQ2-b of the second limit switch and the first normally open contact KM3-1k of the third contactor are also connected in parallel with the first normally open contact KM2-1k of the second contactor.

[0057] The third branch 103 is connected in series with the second normally closed contact SQ4-2b of the fourth limit switch, the second normally open contact KM3-2k of the third contactor, and the coil KM3-0 of the third contactor. The second normally closed contact SQ4-2b of the fourth limit switch and the second normally open contact KM3-2k of the third contactor are also connected in parallel with the normally open contact SQ3-k of the third limit switch.

[0058] Both the fourth branch 104 and the fifth branch 105 are connected to the first linear motor 1. The first end of the first linear motor 1 is connected to the first end of the fourth branch 104 through the second normally open contact KM1-2k of the first contactor, and the second end of the first linear motor 1 is connected to the second end of the fourth branch 104 through the third normally open contact KM1-3k of the first contactor. The first end of the first linear motor 1 is also connected to the second end of the fifth branch 105 through the third normally open contact KM2-3k of the second contactor, and the second end of the first linear motor 1 is also connected to the first end of the fifth branch 105 through the second normally open contact KM2-2k of the second contactor.

[0059] The first end of the power supply 100 is also connected to the first end of the sixth branch 106 and the first end of the seventh branch 107, and the second end of the power supply 100 is also connected to the second end of the sixth branch 106 and the second end of the seventh branch 107.

[0060] The sixth branch 106 is connected in series with a first direct control switch 108, the second normally closed contact SQ3-2b of the third limit switch, the second normally closed contact KM2-2b of the second contactor, and the coil KM1-0 of the first contactor. The first direct control switch 108 is also connected in parallel with the fourth normally open contact KM1-4k of the first contactor.

[0061] The seventh branch 107 is connected in series with the second direct control switch 109, the third normally closed contact SQ4-3b of the fourth limit switch, the second normally closed contact KM1-2b of the first contactor, and the coil KM2-0 of the second contactor. The second direct control switch 109 is also connected in parallel with the fourth normally open contact KM2-4k of the second contactor.

[0062] according to Figure 7 It can be seen that the fourth branch 104 and the fifth branch 105 are used to supply the current of the power supply 100 to the first linear motor 1, and the fourth branch 104 and the fifth branch 105 are respectively provided with the normally open contacts of the first contactor or the second contactor to control the current on and off in the branch; the other branches besides the fourth branch 104 and the fifth branch 105 can be used to control whether the coil of the first contactor or the second contactor is energized, thereby controlling whether the normally open contacts of the first contactor or the second contactor can be closed, thereby controlling the current on and off in the fourth branch 104 and the fifth branch 105.

[0063] Furthermore, based on the power supply 100, the energization of the first branch 101, the second branch 102, and the third branch 103 is controlled by limit switches; the first direct-control switch 108 in the sixth branch 106 and the second direct-control switch 109 in the seventh branch 107 are opened and closed according to the instructions of the control system. In other words, the energization of the first branch 101, the second branch 102, and the third branch 103 is controlled by the first linear motor control mechanism 9, while the energization of the sixth branch 106 and the seventh branch 107 is directly controlled by the control system. The setting of the first direct-control switch 108 and the second direct-control switch 109 allows the control system to directly control the first linear motor 1 to achieve pitch change, thus preventing the inability to change pitch due to the failure of the first linear motor control mechanism 9.

[0064] When power supply 100 supplies power to the first linear motor 1 through the fourth branch 104, the first linear motor 1 operates in the first direction. When power supply 100 supplies power to the first linear motor 1 through the fifth branch 105, the first linear motor 1 operates in the second direction. If the pitch control rod 6 increases the pitch of the propeller when the first linear motor 1 operates in the first direction, then the pitch control rod 6 decreases the pitch of the propeller when the first linear motor 1 operates in the second direction; conversely, if the pitch control rod 6 decreases the pitch of the propeller when the first linear motor 1 operates in the first direction, then the pitch control rod 6 increases the pitch of the propeller when the first linear motor 1 operates in the second direction.

[0065] In this embodiment, the first preset position is taken as the initial position of the switch control lever 91. The working state changes of the first linear motor 1 during the process of the switch control lever 91 moving back and forth between the first preset position and the second preset position are described in conjunction with the circuit diagram. They can be divided into the following four states:

[0066] State 1: When the switch control lever 91 is in the first preset position, the first limit switch and the fourth limit switch are compressed, and SQ1-b in the first branch 101 is open (at this time, SQ3-1b, KM2-1b, and KM3-b in the first branch are closed, and KM1-1k is open), then the first branch 101 is not energized, then KM1-0 is not energized, then KM1-2k and KM1-3k are both open, and the fourth branch 104 is not energized; SQ4-1b in the second branch 102 is open (at this time, SQ4-1b in the second branch is open). If Q2-1b and KM1-1b are closed, and KM3-1k and KM2-1k are open, then the second branch 102 is not energized, KM2-0 is not energized, and KM2-2k and KM2-3k are both open, so the fifth branch 105 is not energized. In the third branch 103, SQ4-2b is open (at this time, SQ3-k in the third branch is also open), so the third branch 103 is not energized, KM3-0 is not energized, and KM3-1k and KM3-2k are both open, while KM3-b is closed. In other words, in state 1, the first linear motor does not work.

[0067] State 2: During the movement of switch control lever 91 from the first preset position to the second preset position, switch control lever 91 no longer compresses the first limit switch and the fourth limit switch. Therefore, SQ1-b in the first branch 101 closes (at this time, SQ3-1b, KM2-1b, and KM3-b in the first branch are still closed), the first branch 101 is energized, KM1-0 is energized, and KM1-2k and KM1-3k close (at this time, KM1-1k and KM1-4k also close, and KM1-1b opens). The fourth branch 1... When power is applied at state 04, the first linear motor 1 operates in the first direction. SQ4-1b in the second branch 102 is closed, but KM3-1k and KM2-1k in the second branch 102 remain open (because KM1-0 is energized, KM1-1b is also open). Therefore, the second branch 102 is not energized, and KM2-0 is not energized, thus the fifth branch 105 is not energized. In the third branch 103, SQ4-2b is closed, but SQ3-k and KM3-2k in the third branch 103 remain open. Therefore, the third branch 103 is not energized, and KM3-0 is not energized. In other words, in state 2, the first linear motor 1 operates in the first direction.

[0068] State 3: When the switch control lever 91 moves to the second preset position, the second limit switch and the third limit switch are compressed, SQ3-1b in the first branch 101 is disconnected (at this time, SQ1-b and KM2-1b in the first branch are still closed), the first branch 101 is de-energized, KM1-0 is de-energized, then KM1-2k and KM1-3k are disconnected (at this time, KM1-1k and KM1-4k are also disconnected, and KM1-1b is closed), the fourth branch 104 is de-energized, and the first linear motor stops working in the first direction; SQ2-b in the second branch 102 is disconnected, KM2-1k is also still disconnected, the second branch 102 is not energized, KM2-0 is not energized, then the fifth branch 105 is not energized; SQ3-k in the third branch 103 is closed, then KM3-0 is energized, then KM3-1k and KM3-2k are closed, and KM3-b is disconnected. In other words, in state 3, the first linear motor 1 is not working.

[0069] State 4: During the movement of switch control lever 91 from the second preset position to the first preset position, switch control lever 91 no longer compresses the second and third limit switches. SQ3-1b in the first branch 101 is closed, but KM3-b remains open. The first branch 101 is not energized, KM1-0 is not energized, and the fourth branch 104 is not energized. SQ2-b in the second branch 102 is closed (at this time, KM3-1k, SQ4-1b, and KM1-1b are still closed). The second branch 102 is energized, KM2-0 is energized, and the fifth branch 105 is energized. The first linear motor 1 operates in the second direction. SQ3-k in the third branch 103 is open, but SQ4-2b and KM3-2k remain closed. The third branch 103 is still energized, and the third coil is energized. That is to say, in state 4, the first linear motor operates in the second direction.

[0070] When the switch control lever 91 moves back to the first preset position, the first limit switch and the fourth limit switch are compressed, returning to state 1, and the first linear motor 1 stops working in the second direction. Based on the cycle of the above four states, this embodiment controls the first linear motor 1 through the first linear motor control mechanism 9, which can keep the propeller speed in a dynamic equilibrium state. In addition, the second linear motor 92 is electrically connected to the control system and can work according to the instructions issued by the control system, thereby changing the pressure on the spring 93. When the spring force changes, the centrifugal force of the flyweight expands or contracts, and the propeller changes to a new speed state. The first linear motor control mechanism makes the propeller maintain a new dynamic equilibrium state at the new speed.

[0071] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. An electric variable-pitch aircraft propeller, characterized in that, include: The propeller hub, propeller blades, pitch control rod, first linear motor, and first linear motor control mechanism; The blades are rotatably connected to the hub; The pitch control rod is arranged axially within the propeller hub and drives the propeller to change pitch by moving axially. The output end of the first linear motor is connected to the pitch rod, and is used to drive the pitch rod to move axially; The circuit system of the first linear motor is equipped with a limit switch; The first linear motor control mechanism is used to control the limit switch; The first linear motor control mechanism includes: a second linear motor, a spring, a switch control lever, and a limit guide; The output end of the second linear motor is connected to one end of the spring; The other end of the spring is connected to the switch control lever; The switch control rod passes through the limiting guide and controls the limit switch by axial movement.

2. The electric variable-pitch aircraft propeller according to claim 1, characterized in that, The propeller hub is rotatably mounted at the output end of the engine; The engine is equipped with a brush at one end near the propeller hub; The propeller hub is fitted with a conductive ring, which is located on the side of the propeller hub closer to the engine and is in contact with the brush.

3. The electric variable-pitch aircraft propeller according to claim 1, characterized in that, The second linear motor is connected to the control system via electrical signals and is used to operate according to the instructions issued by the control system.

4. The electric variable-pitch aircraft propeller according to claim 1, characterized in that, The first linear motor control mechanism also includes a centrifugal flyweight assembly; The centrifugal flyweight assembly includes a flyweight and a flyweight base; The flying weight base is equipped with a pin; The flying weight includes a centrifugal part and a working part, which are connected at an angle, and a pin hole is provided at the connection between the centrifugal part and the working part; The flyweight is rotatably connected to the pin shaft through the pin hole; The working part contacts the switch control lever. When the flyweight rotates around the pin in the direction from the working part to the centrifugal part, the working part can push the switch control lever to compress the spring.

5. An electrically variable pitch airscrew according to claim 4, wherein, The switch control lever includes an input section, an output section, and a connecting section located between the input section and the output section; The cross-sectional area of ​​the connecting part is smaller than that of the input part, the connecting part passes through the limiting guide, and the input part and the output part are located on both sides of the limiting guide; The input section is connected to the spring on the side away from the connecting section, and the working part of the flyweight abuts against the side of the input section away from the spring; the output section is used to control the limit switch.

6. The electric variable-pitch aircraft propeller according to claim 1, characterized in that, The circuit system of the first linear motor also includes a contactor; And / or, the circuit system of the first linear motor is further provided with a direct control switch, which is connected to the electrical signal of the control system and is used to open and close according to the instructions issued by the control system.

7. The electric variable-pitch aircraft propeller according to claim 6, characterized in that, The limit switch includes a first limit switch, a second limit switch, a third limit switch, and a fourth limit switch; When the switch control lever is in the first preset position, the switch control lever compresses the first limit switch and the fourth limit switch, causing the normally open contacts of the first limit switch and the normally closed contacts of the fourth limit switch to close and open. When the switch control lever is in the second preset position, the switch control lever compresses the second limit switch and the third limit switch, causing the normally open contacts of the second limit switch and the normally closed contacts of the third limit switch to close and open.

8. An electrically variable pitch airscrew according to claim 7, wherein, The contactor includes a first contactor, a second contactor, and a third contactor; in the circuit system of the first linear motor: The first terminal of the power supply is connected to the first terminal of the first branch, the first terminal of the second branch, the first terminal of the third branch, the first terminal of the fourth branch, and the first terminal of the fifth branch; The second terminal of the power supply is connected to the second terminal of the first branch, the second terminal of the second branch, the second terminal of the third branch, the second terminal of the fourth branch, and the second terminal of the fifth branch. The first branch is connected in series with the normally closed contact of the first limit switch, the normally closed contact of the third contactor, the first normally closed contact of the third limit switch, the first normally closed contact of the second contactor, and the coil of the first contactor. The normally closed contact of the first limit switch is also connected in parallel with the first normally open contact of the first contactor. The second branch is connected in series with the normally closed contact of the second limit switch, the first normally open contact of the third contactor, the first normally closed contact of the fourth limit switch, the first normally closed contact of the first contactor, and the coil of the second contactor. The normally closed contact of the second limit switch and the first normally open contact of the third contactor are also connected in parallel with the first normally open contact of the second contactor. The third branch is connected in series with the second normally closed contact of the fourth limit switch, the second normally open contact of the third contactor, and the coil of the third contactor. The second normally closed contact of the fourth limit switch and the second normally open contact of the third contactor are also connected in parallel with the normally open contact of the third limit switch. Both the fourth and fifth branches are connected to the first linear motor. The first end of the first linear motor is connected to the first end of the fourth branch through the second normally open contact of the first contactor, and the second end of the first linear motor is connected to the second end of the fourth branch through the third normally open contact of the first contactor. The first end of the first linear motor is also connected to the second end of the fifth branch through the third normally open contact of the second contactor, and the second end of the first linear motor is also connected to the first end of the fifth branch through the second normally open contact of the second contactor.

9. An electrically variable pitch airscrew according to claim 8, wherein, The direct control switch includes a first direct control switch and a second direct control switch; The first end of the power supply is also connected to the first end of the sixth branch and the first end of the seventh branch, and the second end of the power supply is also connected to the second end of the sixth branch and the second end of the seventh branch. The sixth branch circuit is connected in series with the first direct control switch, the second normally closed contact of the third limit switch, the second normally closed contact of the second contactor, and the coil of the first contactor. The first direct control switch is also connected in parallel with the fourth normally open contact of the first contactor. The seventh branch circuit is connected in series with the second direct control switch, the third normally closed contact of the fourth limit switch, the second normally closed contact of the first contactor, and the coil of the second contactor. The second direct control switch is also connected in parallel with the fourth normally open contact of the second contactor.

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