Automatic telescopic propeller blade

Abstract

The invention relates to the field of aerospace, in particular to an automatic telescopic propeller blade which comprises a propeller hub and propeller blades, and the propeller blades comprise large propeller blades and small propeller blades which are of hollow structures; the large paddle and the small paddle are sleeved inside and outside and are in sliding fit; a limiting sealing structure is arranged at the joint of the tail end of the large paddle and the head end of the small paddle; a closed and communicated cavity is formed in the large paddle and the small paddle; a sealing plate is mounted at the free end of the small paddle through a connecting piece; an air valve is arranged on the sealing plate. The blade is of a hollow closed cavity structure, when the propeller does not rotate, the internal air pressure of the cavity of the blade is lower than the external air pressure, the blade is in a contraction state under the action of negative pressure, when the propeller rotates, the blade extends under the action that centrifugal force is larger than negative pressure suction force, and an additional control mechanism is not needed in the whole process; the automatic telescopic propeller blade is a complete automatic telescopic propeller blade, the small propeller blade slides out of the large propeller blade under the action of centrifugal force, the blade extends, and the length change of the propeller blade can be realized without an independent driving device.

Description

Technical Field

[0001] The invention relates to the field of aerospace, in particular to an automatically retractable propeller blade, which is mainly used for propellers or rotors of aircraft or submersibles. Background Art

[0002] The blades on the propeller or rotor are generally mounted on the main shaft and rotate along the main shaft. They can be two or more blades, and the shape varies depending on the needs. Taking the propeller-powered aircraft as an example, the propeller blades must be long enough, combined with the appropriate angle of attack and speed, to provide sufficient power for the aircraft. In actual use, the propeller blades of some aircraft are longer than the fuselage, which is extremely inconvenient for the storage and transportation of the aircraft.

[0003] In order to solve the problem of propellers taking up a lot of space, it is common to fold the blades, of which the most commonly used are mechanical folding structures and centrifugal telescopic structures. The mechanical folding structure is complex and prone to mechanical failure, which affects the flight life; the centrifugal telescopic structure uses centrifugal force to throw the inner and outer blades apart to achieve the extension in the length direction, but most of the contraction is recovered by elastic parts or a separate power device. The rotation of the propeller causes the blades to bear large variable loads, torque and vibration. The elastic recovery of the elastic parts themselves has poor stability, is easy to damage, and has a high maintenance rate. Summary of the invention

[0004] The present invention is aimed at the technical defects existing in the background technology and provides an automatically retractable propeller blade. The main purpose of the present invention is to solve the problem that the aircraft occupies a large space and has insufficient lift during transportation and storage.

[0005] The technical solution adopted by the present invention is: an automatically retractable propeller blade, including a hub and blades, the blades including a large blade and a small blade with a hollow structure; the large blade and the small blade are fitted inside and outside and slidably matched; a limiting sealing structure is provided at the connection between the tail end of the large blade and the head end of the small blade; a closed and connected cavity is formed inside the large and small blades; a sealing plate is installed at the free end of the small blade through a connecting piece, and an air valve is provided on the sealing plate.

[0006] As an optimal technical solution: the limit sealing structure includes a limit platform combination and a sealing ring; the limit platform combination includes a large limit platform arranged on the inner side of the tail end of the large blade and a small limit platform arranged on the outer side of the head end of the small blade, and the large limit platform and the small limit platform cooperate to achieve limiting; the sealing ring is arranged on the outer side of the small limit platform to achieve cavity sealing.

[0007] As a preferred technical solution: the air valve on the sealing plate realizes the regulation of the air pressure inside the cavity of the small blade.

[0008] As a preferred technical solution: the large blade and the small blade have the same cross-sectional structure.

[0009] As a preferred technical solution: the large blade and the small blade have the same axial structure, and the small blade slides along the extension line of the large blade.

[0010] Compared with the prior art, the present invention has the following beneficial effects: 1. The blade disclosed in the present invention is a hollow closed cavity structure. When the propeller is not rotating, the air pressure inside the blade cavity is lower than the external air pressure. The blade is in a contracted state by the negative pressure. When the propeller rotates, the centrifugal force is greater than the negative pressure suction force, and the blade is extended. No additional control mechanism is required in the whole process, and it is realized automatically. 2. The present invention discloses a complete automatically retractable propeller blade. The small propeller blade is acted upon by centrifugal force to slide out from the large propeller blade, and the blade is extended. The length change of the propeller blade can be realized without a separate driving device. The small propeller blade is retracted inwardly under the action of internal negative pressure, and the propeller blade is shortened. The propeller blade can be recovered without mechanical or elastic parts. The propeller has strong stability, occupies less space, and is more convenient to transport and store. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the paddle contraction state of the present invention.

[0012] Figure 2 for Figure 1 AA section view.

[0013] Figure 3 for Figure 2 A partial enlarged view of part B in the middle.

[0014] Figure 4 It is a schematic diagram of the blade extension state of the present invention.

[0015] Figure 5 for Figure 4 AA section view.

[0016] Figure 6 for Figure 5 A partial enlarged view of part B in the middle.

[0017] Figure 7 for Figure 4 Side view of.

[0018] In the figure: a hub 1, a large blade 2, a small blade 3, a sealing structure 4, a sealing plate 5, an air valve 6, and a connecting piece 7. DETAILED DESCRIPTION

[0019] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0020] See attached Figure 1-7The automatic retractable propeller blade disclosed in the present invention comprises a hub 1 and a blade, wherein the blade comprises a large blade 2 and a small blade 3 of a hollow structure; the large blade 2 and the small blade 3 are set inside and outside and slide together. A limit seal structure 4 is provided at the connection between the tail end of the large blade 2 and the head end of the small blade 3; a sealing plate 5 is installed at the free end of the small blade through a bolt or other connecting piece, and an air valve 6 is provided on the sealing plate 5.

[0021] As a preferred embodiment: the cavity of the small blade 3 is connected to the cavity of the large blade 2 to form a closed cavity. The small blade can slide inside the large blade, and the limit sealing structure 4 provided at the overlap of the two includes a limit platform combination and a sealing ring 4-3. The limit platform combination includes a large limit platform 4-1 provided on the inner side of the tail end of the large blade 2 and a small limit platform 4-2 provided on the inner side of the head end of the small blade 3. The large limit platform 4-1 and the small limit platform 4-2 cooperate to achieve the limit, that is, because a section of the head of the large blade bulges inward, a large limit sleeve 4-1 of a small diameter section is formed; a section of the tail of the small blade bulges outward, a small limit platform 4-2 of a large diameter section is formed. The two blades slide relative to each other but cannot detach. During the extension and retraction of the blades, a variable cavity will be formed between the other parts of the large blade and the small blade. This cavity is connected to the outside world and will not generate resistance to the compressed medium.

[0022] The sealing ring 4-3 is arranged outside the small limiting platform 4-2, a groove is opened on the outer wall of the small limiting platform, and the sealing ring 4-3 is embedded in the groove to seal the cavity of the large blade and isolate the medium.

[0023] The sealing ring can be set on the inner limit platform of the large blade, and the sealing ring of the outer limit platform of the small blade can be cancelled accordingly. They must not be sealed at the same time, otherwise the medium will be compressed and the movement resistance will increase.

[0024] As a preferred solution, the connecting end of the hub 1 is inserted into the large blade 2, the hub 1 is fixed to the large blade 2, and the contact surface of the two is coated with sealant to ensure sealing. A sealing gasket is arranged between the sealing plate 5 and the end surface of the small blade 3, and the air valve 6 arranged on the sealing plate 5 is connected to the cavity of the small blade 3. The sealing plate 5 is fixed to the free end of the small blade 3, and the contact surface of the two is coated with sealant, so that a connected closed cavity is formed between the large blade 2 and the small blade 3. The air pressure in the blade cavity is adjusted by the air valve 6 installed on the sealing plate 5, so that the air pressure inside the blade cavity is lower than the external air pressure, thereby generating a contraction force to shorten the length of the blade.

[0025] As a preferred embodiment, the shape of the blade is linear.

[0026] As another preferred embodiment, the blades formed by sweeping the contour along an arc or a spiral line can also realize the automatic telescopic movement of the blades.

[0027] As a preferred embodiment, the present invention discloses a telescopic structure between two sections of blades. According to actual needs, it can also be designed as a telescopic structure of multiple sections of blades.

[0028] The working process of the present invention is as follows: In the initial state, the small blade is retracted inside the large blade; the air in the cavities of the large blade and the small blade is evacuated through the air valve, so that the air pressure inside the cavity is lower than the external air pressure, generating suction and maintaining the retracted state; When the propeller rotates, the blade's small paddles are acted upon by centrifugal force and slide outward, the small paddles slide out, and the entire blade extends; When the propeller speed decreases, the centrifugal force decreases until it stops. At this time, the centrifugal force is 0, and the suction force generated by the negative pressure is greater than the friction between the blades. The small blades are gradually sucked back under the action of the vacuum in the cavity, and the blades shorten.

[0029] As a preferred technical solution: The propeller blade disclosed in the present invention is divided into multiple parts. Its main components, large blades and small blades, are formed by composite material molds, and the hub and cover plate are respectively made of composite materials. The joint surface is bonded with structural adhesive or coated with sealant and connected with screws or riveted to ensure the integrity and sealing of the blade. Because the large blades and small blades of the blades have the same cross-section, they can be pultruded by lightweight and high-strength alloys and then installed and fixed. Under the premise of ensuring sealing, the installation holes can be increased to make a multi-stage detachable structure larger than the blades at both ends. Because propellers generally install two or more blades in a circular array, the blades are required to have good consistency to facilitate the overall dynamic and static balance.

Claims

1. An automatically retractable propeller blade, comprising a hub and a blade, characterized in that: The blades include a large blade and a small blade with a hollow structure; the large blade and the small blade are fitted inside and outside and slide together; a limit sealing structure is provided at the connection between the tail end of the large blade and the head end of the small blade; a closed and connected cavity is formed inside the large and small blades; a sealing plate is installed at the free end of the small blade through a connecting piece, and an air valve is provided on the sealing plate.

2. The automatically retractable propeller blade according to claim 1, characterized in that: The position limiting sealing structure comprises a position limiting platform assembly and a sealing ring; The limit platform assembly comprises a large limit platform arranged at the inner side of the tail end of the large blade and a small limit platform arranged at the outer side of the head end of the small blade, and the large limit platform and the small limit platform cooperate to achieve limit; The sealing ring is arranged on the outside of the small limiting platform to achieve cavity sealing.

3. The automatically retractable propeller blade according to claim 1, characterized in that: The air valve on the sealing plate realizes the regulation of the air pressure inside the cavity of the small blade.

4. The automatically retractable propeller blade according to claim 1, characterized in that: The large blade and the small blade have the same cross-sectional structure.

5. The automatically retractable propeller blade according to claim 1, characterized in that: The large blade and the small blade have the same axial structure, and the small blade slides along the extension line of the large blade.

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