Unpowered automatic feathering mechanism of variable pitch mechanism of aerial variable pitch propeller and propeller

Abstract

The automatic feathering mechanism comprises a variable-pitch disc, a sliding groove is formed in the side wall of the variable-pitch disc, the sliding groove is in sliding connection with a propeller handle variable-pitch pin, a through hole is formed in the center of the variable-pitch disc, a variable-pitch nut is arranged in the through hole of the variable-pitch disc, and the variable-pitch nut is connected with the variable-pitch disc. The variable-pitch nut is internally in threaded connection with a variable-pitch lead screw, a lower limiting piece is arranged at the lower end of the variable-pitch lead screw, and an upper limiting piece is arranged at the upper end of the variable-pitch lead screw; the variable-pitch disc is connected with the variable-pitch nut in a sliding mode, and a limiting seat is arranged on the outer wall of the variable-pitch nut and located above the variable-pitch disc; the paddle handle variable pitch pin is eccentrically connected with a paddle handle of the paddle, and the axis of the paddle handle of the paddle is not coaxial with the pneumatic center of the paddle. After the power motor fails, unpowered fast feathering can be achieved, fuselage resistance is reduced, and the possibility of safe landing of the aircraft is increased.

Description

Technical Field

[0001] The invention relates to the technical field of propellers, in particular to an unpowered automatic feathering mechanism of a pitch-changing mechanism of an aerial variable-pitch propeller and a propeller. Background Art

[0002] Feathering means adjusting the propeller blade angle to be almost parallel to the aircraft's flight direction, minimizing the propeller's resistance in the air.

[0003] When the aircraft is in cruising mode, the engine / power motor fails to work properly. By locking the power source to stop the propeller from rotating, the propeller feathering function can reduce the wind resistance of the propeller and prevent the faulty engine from being dragged back by the high-speed rotating propeller, thereby reducing the aircraft's resistance, improving the aircraft's gliding performance, and increasing the possibility of the aircraft landing safely. The propeller after feathering reduces the aerodynamic interference on the aircraft, making it easier for the aircraft to maintain a stable flight attitude.

[0004] Traditionally, feathering is mainly achieved by variable pitch propellers in the air, usually through hydraulic systems, electric systems or mechanical systems with power mode to achieve the feathering function. When the pilot triggers the feathering command, the system automatically adjusts the angle of the propeller blades to reach the feathering position.

[0005] like Figure 1 As shown in the figure, the pitch mechanism of the variable pitch propeller driven by the motor in the air is composed of a pitch screw, a pitch nut, a pitch disc and a pitch nut; the pitch hub clamps the pitch screw axially for positioning, and the motor drives the pitch screw to rotate in both directions at a uniform speed. The rotation of the pitch screw drives the pitch nut to move axially, thereby causing the pitch disc to move axially, the pitch disc slot to move axially, and the pitch pin of the propeller handle to move in a circular motion to achieve blade pitch change, as shown in the figure. Figure 2 As shown, the variable pitch disc is driven from the upper limit to the lower limit, and the movement time is relatively long, which places extremely high requirements on the speed of the variable pitch motor.

[0006] like Figure 3 As shown in the figure, the difference between hydraulic pitch change and electric pitch change is that the power source of the pitch change plate is the hydraulic oil pressure and the pitch change spring. The pressure is provided by the engine hydraulic oil pump. When the pressure is greater than the spring thrust, the oil pressure pushes the pitch change plate integrated with the piston to move upward, driving the pitch change pin of the propeller handle to rotate in a circle, completing the function of reducing the pitch angle and reaching the corresponding working angle. When the reduced hydraulic pressure is lower than the pitch change spring thrust, the spring pushes the pitch change plate downward to complete the function of reducing the pitch angle. When the oil pressure disappears completely, the spring thrust acts to the lower limit, which is the propeller feathering position. The safety of hydraulic pitch change mainly depends on the fatigue performance of the spring, and the spring plays a decisive role.

[0007] Both existing technologies require the pilot to actively trigger the propeller feathering command. When the propeller loses power, the propeller feathering cannot be completed automatically, causing the propeller to lose some energy and reducing the gliding time. Summary of the invention

[0008] In view of the above-mentioned defects in the prior art, an object of the present invention is to provide an unpowered automatic feathering mechanism for an aerial variable pitch propeller pitch changing mechanism and a propeller.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions: On the one hand, the present invention provides an unpowered automatic pitch-feeding mechanism for an aerial variable-pitch propeller pitch-changing mechanism, comprising a pitch disc, a side wall of the pitch disc being provided with a slide groove, the slide groove being slidably connected to a pitch pin of a propeller handle, a through hole being provided at the center of the pitch disc, a pitch nut being provided in the through hole of the pitch disc, the pitch nut being internally threadedly connected to a pitch screw, a lower limit piece being provided at the lower end of the pitch screw, and an upper limit piece being provided at the upper end of the pitch screw; the pitch disc is slidably connected to the pitch nut, and a limit seat is provided on the outer wall of the pitch nut above the pitch disc; the pitch pin of the propeller handle is eccentrically connected to the propeller handle of a blade, and the propeller handle axis of the blade is not coaxial with the aerodynamic center of the blade.

[0010] Furthermore, the space between the upper limit member and the lower limit member is a movement range of the pitch nut, and this range is defined as a range of variation of the working pitch angle; The range between the limit seat of the pitch-changing nut and the lower limit piece is the movement range of the pitch-changing disc, and the lower limit piece is the feathering position. This range is defined as the range of variation of the working point and the feathering position.

[0011] Furthermore, a flexible material is provided between the limit seat and the pitch disc.

[0012] Furthermore, the upper limit member and the lower limit member are both composite bearings, and the composite bearing comprises a large diameter portion and a small diameter portion, and the outer diameter of the large diameter portion is larger than the outer diameter of the variable pitch screw; Specifically, the upper limit member is rotatably connected to the upper end of the variable pitch lead screw; the lower limit member is rotatably connected to the lower end of the variable pitch lead screw.

[0013] Furthermore, a guide frame is provided at the upper end of the pitch variable nut, the guide frame is provided with a first guide hole axially penetrating therethrough, the pitch variable disc is provided with a second guide hole axially penetrating therethrough, the first guide hole corresponds to the second guide hole, and at least two of each are provided; Specifically, a first sliding guide is disposed in the first guide hole, and a second sliding guide is disposed in the second guide hole. Specifically, guide pillars are slidably arranged in the corresponding first sliding guide members and second sliding guide members.

[0014] Furthermore, the first sliding guide and the second sliding guide are copper sleeves or linear bearings.

[0015] Furthermore, the number of the first guide holes and the second guide holes is the same as that of the slide grooves; Specifically, the second guide holes are evenly distributed along the circumference of the pitch disc; Specifically, the second guide hole is located at the maximum outer diameter d of the pitch disc. max and 1 / 2 the maximum outer diameter d max between.

[0016] Furthermore, a third sliding guide is fixedly arranged in the central through hole of the pitch change disc, and the third sliding guide is slidably connected with the pitch change nut; Specifically, the flexible material is a return spring or a hollow rubber tube or a nylon pad.

[0017] Further, the third sliding guide member is a steel guide sleeve, and the steel guide sleeve is embedded in the inner wall of the through hole of the pitch disc; Specifically, the steel guide sleeve is provided with an inner ring, the flexible material is a return spring, and the return spring extends into the steel guide sleeve and sits on the inner ring.

[0018] In another aspect, the present invention provides an aerial variable pitch propeller, comprising an upper propeller hoop and a lower propeller hoop, and is characterized in that it also includes the unpowered automatic propeller feathering mechanism described in the first aspect; the upper limit member is fixedly connected to the upper propeller hoop, and the upper end of the guide column is fixedly connected to the upper propeller hoop; the lower limit member is fixedly connected to the lower propeller hoop, and the lower end of the guide column is fixedly connected to the lower propeller hoop; the upper propeller hoop and the lower propeller hoop rotatably clamp the propeller handle.

[0019] Compared with the prior art, the present invention has the following beneficial effects: 1. After the power motor fails, the present invention can quickly feather the propellers without power, thereby reducing the fuselage resistance and increasing the possibility of safe landing of the aircraft.

[0020] 2. Compared with the traditional feathering function, the present invention uses aerodynamic force as the power source and the variable pitch disc as the slave. The traditional feathering function can only rely on the rotation of the variable pitch motor as the power source to drive the blades to rotate; the present invention has a high safety factor and a fast response speed. The feathering function does not rely on hydraulic power, springs and variable pitch motors, and the rate of change depends on the propeller speed and the incoming flow speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the structure of the pitch-changing mechanism of a conventional electric variable-pitch propeller in the air; Figure 2 It is a schematic diagram of the axial displacement of the pitch disc driving the circular motion of the pitch pin; Figure 3It is a schematic diagram of the structure of the pitch-changing mechanism of a conventional hydraulic variable-pitch propeller in the air; Figure 4 It is a structural schematic diagram of the unpowered automatic feathering mechanism of the pitch-changing mechanism of the variable-pitch propeller in the air of the present invention; Figure 5 It is a structural schematic diagram of the blade in the present invention.

[0022] In the figure: 1. upper limit member; 2. pitch-changing screw; 3. guide frame; 4. guide column; 5. first sliding guide member; 6. second sliding guide member; 7. pitch-changing plate; 8. return spring; 9. third sliding guide member; 10. lower limit member; 11. pitch-changing nut. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Embodiment 1: See also Figures 4 to 5 The present invention provides an unpowered automatic pitch-feeding mechanism for a pitch-changing propeller in the air, comprising a pitch-changing disc 7, a side wall of which is provided with a sliding groove for slidably connecting a pitch-changing pin of a propeller handle, a through hole is provided in the center of the pitch-changing disc 7, a pitch-changing nut 11 is provided in the through hole of the pitch-changing disc 7, the pitch-changing nut 11 is internally threadedly connected to a pitch-changing screw 2, a lower limit member 10 is provided at the lower end of the pitch-changing screw 2, an upper limit member 1 is provided at the upper end of the pitch-changing screw 2, the pitch-changing disc 7 is slidably connected to the pitch-changing nut 11, a limited position seat is provided on the outer wall of the pitch-changing nut 11 above the pitch-changing disc 7, the pitch-changing pin of the propeller handle is eccentrically connected to the propeller handle of the blade, the propeller handle axis of the blade is not coaxial with the aerodynamic center of the blade, and there is a distance between the aerodynamic center of the blade and the propeller handle axis, so that when the propeller rotates in the working state, the air generates a force arm relative to the propeller handle axis at the aerodynamic center, hereinafter referred to as aerodynamic force.

[0025] Among them, the sliding connection between the pitch disc 7 and the pitch nut 11 is that the aerodynamic center of the blade is not coaxial with the propeller shaft. The head-down torque generated when the propeller rotates will cause the blade to rotate around the propeller shaft, so that the pitch pin drives the pitch disc 7 to move toward the limit seat of the pitch nut 11. During the entire working state, the pitch disc is always close to the limit seat of the pitch nut 11. Changing the pitch angle requires rotating the pitch screw 2 to drive the pitch nut 1 to move up and down, thereby changing the position of the pitch disc 7.

[0026] When the power motor fails, the aircraft has a forward flight speed, and the incoming airflow generates aerodynamic force on the blades, which acts on the blades to generate a lifting torque, which serves as a power source to drive the variable pitch disc 7 to move downward, realizing the feathering function. The advantage of this patent is that it can quickly feather the blades without power, and the change rate depends on the propeller speed and the incoming flow speed.

[0027] Compared with the traditional feathering function, the pneumatic force of the patent is the power source and the pitch disc 7 is the slave. The traditional feathering function can only rely on the rotation of the pitch motor as the power source to drive the blades to rotate. The patent has a high safety factor and a fast response speed. The feathering function does not rely on hydraulic power, springs, or pitch motors.

[0028] Specifically, the slide groove is slidably connected to the blade handle pitch change pin via a nylon or copper slider.

[0029] Specifically, the space between the upper limit member 1 and the lower limit member 10 is a movement range of the pitch nut 11 , and this range is defined as a working pitch angle variation range.

[0030] Specifically, the range between the limit seat of the pitch nut 11 and the lower limit member 10 is the movement range of the pitch disc 7, and the lower limit member 10 is the feathering position. This range is defined as the working point and the feathering position variation range.

[0031] Furthermore, a flexible material is provided between the limit seat and the pitch disc 7 .

[0032] During the powered flight phase, the aerodynamic force drives the blades to rotate around the handle, generating a head-down torque, thereby driving the pitch disc 7 to move upward, so that the pitch disc 7 is softly pressed against the limit seat, and a flexible material is provided to prevent the upward movement from being too fast or the impact load from being uncontrollable; the pitch screw 2 is rotated to drive the pitch nut 11 to move in the pitch nut movement range, changing the up and down positions of the pitch disc and determining the propeller working angle; When the aircraft is in forward flight / cruise mode, the power motor stops rotating due to a fault, and the incoming air blows and acts on the aerodynamic center, causing the blades to generate a lifting moment. The pitch disc 7 is driven downward by the propeller handle and becomes a feathering propeller. At this time, the flexible material is in a relaxed state.

[0033] That is, in the powered flight state, the nose-up torque drives the pitch disc 7 to move upward to the working position; in the unpowered flight state, the flexible material and the nose-down torque return the pitch disc 7 to the feathering position.

[0034] Preferably, the flexible material is a return spring 8 or a hollow rubber tube or a nylon pad, which plays a role of buffering and returning.

[0035] Specifically, the upper limit member 1 and the lower limit member 10 are both composite bearings, and the composite bearing includes a large diameter portion and a small diameter portion. The outer diameter of the large diameter portion is larger than the outer diameter of the variable pitch screw 2. The upper limit member 1 is rotatably connected to the upper end of the variable pitch screw 2 and is positioned by a step; the lower limit member 10 is rotatably connected to the lower end of the variable pitch screw 2 and is positioned by a step.

[0036] Embodiment 2: On the basis of Example 1, in this embodiment, a guide frame 3 is provided at the upper end of the pitch variable nut 11, and the guide frame 3 is provided with a first guide hole axially extending therethrough, and the pitch variable plate 7 is provided with a second guide hole axially extending therethrough, and the first guide hole corresponds to the second guide hole, and at least two of each are provided; a first sliding guide member 5 is provided in the first guide hole, and a second sliding guide member 6 is provided in the second guide hole, and guide columns 4 are slidably provided in the corresponding first sliding guide members 5 and second sliding guide members 6.

[0037] Preferably, the first sliding guide 5 and the second sliding guide 6 are copper sleeves or linear bearings.

[0038] Specifically, the guide column 4 enables the pitch disc 7 and the pitch nut 11 to move only axially after being loaded, without radial and rotational forces, thereby improving the horizontality of the pitch disc 7 and the pitch nut 11.

[0039] Specifically, the number of the first guide holes and the second guide holes is the same as the slide groove, that is, a three-blade propeller requires three guide pillars 4, a four-blade propeller requires four guide pillars 4, and so on. The relationship between the number of blades and the number of guide pillars is arranged in a similar manner; the second guide holes are evenly distributed along the circumference of the variable pitch disc 7.

[0040] Specifically, the second guide hole is located at the maximum outer diameter d of the pitch disc 7. max and 1 / 2 the maximum outer diameter d max When the pitch disc 7 meets the structural strength standard, the closer the position of the second guide hole is to the maximum outer diameter d max , the pitch disc 1 has the highest motion flatness and the best pitch change accuracy.

[0041] Specifically, the diameter of the guide column 4 needs to be calculated according to the torque applied by the propeller aerodynamic load on the pitch disc 7, and must satisfy the requirement that the bending deformation of the guide column 4 does not exceed 0.1 mm under double load.

[0042] The central through hole of the pitch disc 7 is fixedly provided with a third sliding guide 9, and the third sliding guide 9 is slidably connected with the pitch nut 11. The third sliding guide 9 is a steel guide sleeve, and the steel guide sleeve is provided with an inner ring. The flexible material is a return spring 8, and the return spring 8 extends into the steel guide sleeve and sits on the inner ring.

[0043] Specifically, the compression amount and compression force of the return spring 8 are determined by the conversion of aerodynamic torque generated at a certain rotation speed into axial force, but are not limited to these conditions.

[0044] Specifically, the steel guide sleeve is embedded in the inner wall of the through hole of the pitch disc 7 , and the steel guide sleeve plays the role of sliding guide and preventing the return spring 8 from wearing the pitch disc 7 .

[0045] Embodiment 3: On the basis of Example 2, when the unpowered automatic propeller feathering mechanism of the pitch changing mechanism of the variable pitch propeller in the air is applied to the propeller, the upper limit member 1 is fixedly connected to the upper propeller hoop, the upper end of the guide column 4 is fixedly connected to the upper propeller hoop, the lower limit member 10 is fixedly connected to the lower propeller hoop, the lower end of the guide column 4 is fixedly connected to the lower propeller hoop, and the upper propeller hoop and the lower propeller hoop rotate to clamp the propeller handle.

[0046] All components and connection methods of components not discussed in this application belong to the known technologies in this technical field and can be directly applied without further explanation.

[0047] In the present invention, the term "plurality" refers to two or more than two, unless otherwise clearly defined. The terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0048] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by terms such as “upper”, “lower”, “left”, “right”, “front” and “back” are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation, and therefore, cannot be understood as a limitation on the present invention.

[0049] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An unpowered automatic pitch-feathering mechanism for a variable pitch propeller in the air, comprising a pitch disc, a side wall of which is provided with a slide groove, the slide groove is slidably connected with a pitch pin of a propeller handle, a through hole is provided at the center of the pitch disc, a pitch nut is provided in the through hole of the pitch disc, the pitch nut is internally threadedly connected with a pitch screw, a lower limit piece is provided at the lower end of the pitch screw, and an upper limit piece is provided at the upper end of the pitch screw; It is characterized in that The pitch disc is slidably connected with the pitch nut, and a limited position seat is arranged on the outer wall of the pitch nut above the pitch disc; The propeller handle pitch-changing pin is eccentrically connected to the propeller handle of the blade, and the propeller handle axis of the blade is not coaxial with the aerodynamic center of the blade.

2. The unpowered automatic feathering mechanism of the variable pitch propeller pitch changing mechanism in the air according to claim 1, characterized in that: The range between the upper limit member and the lower limit member is the movement range of the pitch nut, and this range is defined as the range of variation of the working pitch angle; The range between the limit seat of the pitch-changing nut and the lower limit piece is the movement range of the pitch-changing disc, and the lower limit piece is the feathering position. This range is defined as the range of variation of the working point and the feathering position.

3. The unpowered automatic feathering mechanism of the variable pitch propeller pitch changing mechanism in the air according to claim 1, characterized in that: A flexible material is arranged between the limit seat and the pitch disc.

4. The unpowered automatic feathering mechanism of the variable pitch propeller pitch changing mechanism in the air according to claim 1, characterized in that: The upper limit member and the lower limit member are both composite bearings, and the composite bearing comprises a large diameter portion and a small diameter portion, and the outer diameter of the large diameter portion is larger than the outer diameter of the variable pitch screw; The upper limit member is rotatably connected to the upper end of the variable pitch lead screw; the lower limit member is rotatably connected to the lower end of the variable pitch lead screw.

5. The unpowered automatic feathering mechanism of the variable pitch propeller pitch changing mechanism in the air according to claim 1, characterized in that: A guide frame is provided at the upper end of the pitch variable nut, the guide frame is provided with a first guide hole axially penetrating therethrough, the pitch variable disc is provided with a second guide hole axially penetrating therethrough, the first guide hole corresponds to the second guide hole, and at least two of each are provided; A first sliding guide is disposed in the first guide hole, and a second sliding guide is disposed in the second guide hole. Guide pillars are slidably arranged in the corresponding first sliding guide member and the second sliding guide member.

6. The unpowered automatic feathering mechanism of the variable pitch propeller pitch changing mechanism in the air according to claim 5, characterized in that: The first sliding guide and the second sliding guide are copper sleeves or linear bearings.

7. The unpowered automatic feathering mechanism of the variable pitch propeller pitch changing mechanism in the air according to claim 5, characterized in that: The number of the first guide holes and the second guide holes is the same as that of the slide grooves; The second guide holes are evenly distributed along the circumference of the pitch disc; The second guide hole is located at the maximum outer diameter d of the pitch disc. max and 1 / 2 the maximum outer diameter d max between.

8. The unpowered automatic feathering mechanism of the variable pitch propeller pitch changing mechanism in the air according to claim 3, characterized in that: A third sliding guide is fixedly arranged in the central through hole of the pitch change disc, and the third sliding guide is slidably connected to the pitch change nut; The flexible material is a return spring or a hollow rubber tube or a nylon pad.

9. The unpowered automatic feathering mechanism of the variable pitch propeller pitch changing mechanism in the air according to claim 8, characterized in that: The third sliding guide member is a steel guide sleeve, and the steel guide sleeve is embedded in the inner wall of the through hole of the pitch disc; The steel guide sleeve is provided with an inner ring, and the flexible material is a return spring, which extends into the steel guide sleeve and sits on the inner ring.

10. An aerial variable pitch propeller, comprising an upper propeller hoop and a lower propeller hoop, characterized in that: Also includes the unpowered automatic feathering mechanism as claimed in claim 5; The upper limit member is fixedly connected to the upper paddle hoop, and the upper end of the guide column is fixedly connected to the upper paddle hoop; the lower limit member is fixedly connected to the lower paddle hoop, and the lower end of the guide column is fixedly connected to the lower paddle hoop; the upper paddle hoop and the lower paddle hoop rotatably clamp the paddle handle.

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