Turboprop engine and variable pitch device thereof

Abstract

The invention aims to provide a turboprop engine and a variable pitch device thereof. The variable pitch device comprises an outer shell, a piston, an adjusting piece, a locking piece and a flow path. The piston divides the interior of the outer shell into a first cavity and a second cavity, a third cavity is defined between the adjusting piece and the outer shell, and the locking piece is in transmission connection with the adjusting piece. When the fluid pressure in the second cavity is larger than a pressure threshold value, the adjusting piece is driven to move in the direction of compressing the elastic piece and can drive the locking piece to move to the first position, and when the fluid pressure in the second cavity is smaller than the pressure threshold value, the elastic piece can elastically reset and drive the adjusting piece to act. The adjusting piece drives the locking piece to move to the second position, the locking piece allows the piston to move at the first position, and the locking piece limits the piston to move at the second position. By means of the variable pitch device, the propeller fan can be prevented from moving towards the flat propeller at any pitch angle position.

Description

Technical Field

[0001] The present invention relates to the technical field of turboprop engines, and in particular to a turboprop engine and a variable pitch device thereof. Background Art

[0002] Common turboprop engines and open rotor engines are equipped with variable pitch mechanisms for online adjustment of the propeller fan pitch angle so that the propeller fan in different working conditions can operate at the appropriate incoming flow angle of attack, thereby improving work efficiency.

[0003] The current variable pitch mechanism usually uses a hydraulic actuator to drive the fork to move axially for large adjustment torque loads, and then drives the propeller connected to the rocker arm to rotate to achieve pitch adjustment. Since the propeller will produce a lot of resistance to the engine when it is in a small pitch position, and it is very easy to cause overspeed, which will bring serious consequences. Therefore, considering the engine safety requirements, when there is a large amount of leakage in the actuator, it is required to make the propeller feather or lock it in the current position.

[0004] At present, the locking mechanism in the actuator cylinder adopts a method of adding a spring, high-pressure gas to the large-pitch oil chamber of the actuator cylinder or installing a counterweight on the propeller shaft, so that the actuator cylinder automatically moves in the large-pitch direction without hydraulic actuation to drive the propeller to feather, but this method can only provide a small feathering torque load. Schwartz Robert A. and others designed a self-locking structure in the form of a trapezoidal screw (Schwartz Robert A., Carvalho Paul, Cutler Mark J.. Large-scale Advanced Prop-fan pitch change actuator and control design report. Hamilton Standard Division United Technologies Coproration, 1986.), but such a locking mechanism has a complex structure, which brings challenges to reliability and processing and manufacturing.

[0005] For hydraulically actuated variable pitch mechanisms under large adjustment torque, how to implement a mechanism that prevents the propeller from moving toward flat propeller at any pitch angle position is a problem that needs to be solved urgently. Summary of the invention

[0006] The object of the present invention is to provide a variable pitch device which can prevent a propeller from moving toward a flat pitch at any pitch angle position.

[0007] A pitch control device for achieving the above-mentioned purpose comprises:

[0008] outer shell;

[0009] A piston is disposed in the outer shell and is slidably and sealingly matched with the outer shell to separate the interior of the outer shell into a first chamber and a second chamber;

[0010] The adjusting member is elastically supported in the second chamber by the elastic member, and a third chamber is enclosed between the adjusting member and the outer shell;

[0011] A locking member drivingly connected to the adjusting member; and

[0012] a flow path, comprising a first flow path communicating with the first chamber, a second flow path communicating with the second chamber, and a third flow path communicating with the third chamber;

[0013] When the fluid pressure in the second chamber is greater than a pressure threshold, the adjusting member is driven to move in the direction of compressing the elastic member, and can drive the locking member to move to the first position; when the fluid pressure in the second chamber is less than the pressure threshold, the elastic member can elastically reset and drive the adjusting member to actuate, so that the adjusting member drives the locking member to move to the second position; the locking member allows the piston to move in the first position, and restricts the piston movement in the second position.

[0014] In one or more embodiments, the pressure threshold is calculated by the following formula (1):

[0015]

[0016] Among them, p Bmin is the pressure threshold, f max is the maximum pressure within the compression stroke of the elastic member, S b is the cross-sectional area of ​​the third chamber, p 0 is the oil pressure in the third chamber.

[0017] In one or more embodiments, the outer shell includes an outer tube wall and a center rod arranged in the outer tube wall, and the piston includes a piston part, a sleeve part and a matching part. The piston part is sleeved on the outside of the center rod and is slidably sealed with the center rod. The piston part extends radially outward from the sleeve part and is slidably sealed with the outer tube wall. The matching part is arranged in the second chamber. In the second position, the locking member abuts against the matching part to limit the movement of the piston.

[0018] In one or more embodiments, the adjusting member is sleeved on the outer periphery of the central rod, the elastic member is a coil spring sleeved on the outer periphery of the central rod, and the locking member is a cam hinged on the outer side of the central rod;

[0019] The adjusting member has a connecting opening, the cam has a rod portion, and a first convex portion and a second convex portion are arranged in the connecting opening;

[0020] When the adjusting member moves in a direction to compress the elastic member, the first protrusion cooperates with the rod portion to make the locking member rotate along the first direction, so that the locking member located at the first position can move to the second position;

[0021] When the adjusting member moves in a direction away from the elastic member, the second protrusion cooperates with the rod portion to make the locking member rotate along the second direction, so that the locking member located at the second position can move to the first position;

[0022] The first direction is opposite to the second direction.

[0023] In one or more embodiments, the connection opening has an inner annular wall and an outer annular wall, the inner annular wall protrudes toward the locking member relative to the outer annular wall, the first protrusion is arranged in a portion of the inner annular wall protruding from the outer annular wall and protrudes toward the connection opening, and the second protrusion is arranged at an end of the outer annular wall and protrudes toward the connection opening;

[0024] The center rod is provided with a first step portion, and the outer side of the outer ring wall is provided with a second step portion. When the adjusting member moves along the center rod in a direction to compress the elastic member, the first step portion can abut against the second step portion to limit the continued movement of the adjusting member.

[0025] Wherein, in the second position, the first step portion abuts against the second step portion, and when the locking member moves between the first position and the second position, at least a portion of the rod portion contacts the second protrusion.

[0026] In one or more embodiments, the central rod has a first rod segment and a second rod segment, and the outer diameter of the first rod segment is smaller than the outer diameter of the second rod segment, so as to form the first step portion between the first rod segment and the second rod segment;

[0027] The outer annular wall comprises a first annular wall segment and a second annular wall segment, wherein the inner diameter of the first annular wall segment is smaller than the inner diameter of the second annular wall segment, so as to form the second step portion between the first annular wall segment and the second annular wall segment;

[0028] Among them, a convex ring portion convexly arranged toward the radial inner side is further provided on a side of the first annular wall segment away from the second annular wall segment. In the assembled state, the convex ring portion and the first rod segment are slidably sealed and matched, and the second annular wall segment and the second rod segment are slidably sealed and matched. The inner diameter of the first annular wall segment is larger than the outer diameter of the first rod segment, but smaller than the outer diameter of the second rod segment. The axial sides of the third chamber are defined by the convex ring portion and the first step portion, and the radial sides are defined by the outer annular wall and the first rod segment.

[0029] In one or more embodiments, in the second position, the mating surface of the cam abuts against the mating portion to limit the movement of the piston;

[0030] Wherein, the matching surface is an arc surface, and a line connecting the center of a circle where the arc surface extends and the rotation center of the cam is parallel to the axial direction of the center rod.

[0031] In one or more embodiments, when the mating surface abuts against the mating portion, along the axial direction of the center rod, there is a first distance between the abutment point between the mating surface and the mating portion and the rotation center, and along the radial direction of the center rod, there is a second distance between the rotation center and the mating portion, and the first distance and the second distance satisfy the following relationship (2):

[0032] μh>l (2);

[0033] Wherein, l is the first distance, h is the second distance, and μ is the friction coefficient between the matching portion and the matching surface.

[0034] In one or more embodiments, the first flow path, the second flow path, and the third flow path are opened in the central rod.

[0035] On the other hand, according to some embodiments of the present application, there is also provided a turboprop engine, which includes a propfan and a variable pitch device as described above;

[0036] Wherein, a shift fork is arranged on the piston, and the propeller fan is transmission-connected to the piston via the shift fork.

[0037] The beneficial effects of the present invention are:

[0038] The pitch-changing device of this configuration uses the oil pressure and spring of the second cavity to drive the adjusting member, controls the contact state between the locking member and the piston, and realizes one-way locking in the case of leakage in the large-pitch oil cavity to prevent the propeller from moving in the flat-paddle direction. At the same time, the mechanism for realizing one-way locking only includes four parts: spring, adjusting member, locking member, and cam. It has a simple structure and is easy to process, which can effectively improve the reliability of the pitch-changing actuator with a locking mechanism.

[0039] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0041] Figure 1 A half-section schematic diagram of some embodiments of the pitch control device is shown;

[0042] Figure 2 for Figure 1 A magnified schematic diagram of part A;

[0043] Figure 3 A partial schematic diagram showing some embodiments of the pitch control device in the second position;

[0044] Figure 4 for Figure 3 The enlarged schematic diagram of the middle B part;

[0045] Figure 5 for Figure 3 Enlarged schematic diagram of middle C part;

[0046] Figure 6 A partial schematic diagram of some embodiments of the pitch control device in a first position is shown;

[0047] Figure 7 for Figure 6 The enlarged schematic diagram of the middle D part;

[0048] Figure 8 for Figure 6 Enlarged schematic diagram of part E in the middle. DETAILED DESCRIPTION

[0049] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0051] In order to provide a turboprop engine capable of preventing a propeller from moving toward a flat propeller at any pitch angle position, on the one hand, according to some embodiments of the present application, a variable pitch device is provided. Figure 1 A half-section schematic diagram of some embodiments of the pitch control device is shown. Figure 2 for Figure 1 A magnified schematic diagram of part A; Figure 3 A partial schematic diagram showing some embodiments of the pitch control device in the second position; Figure 4 for Figure 3 The enlarged schematic diagram of the middle B part; Figure 5 for Figure 3 Enlarged schematic diagram of middle C part; Figure 6 A partial schematic diagram of some embodiments of the pitch control device in a first position is shown; Figure 7 for Figure 6 The enlarged schematic diagram of the middle D part; Figure 8 for Figure 6 Enlarged schematic diagram of part E in the middle.

[0052] The pitch device includes an outer shell 1, a piston 2, an adjusting member 3 and a locking member 4. The interior of the outer shell 1 provides a space that allows the remaining components of the pitch device to be accommodated. The piston 2 is arranged in the outer shell 1 and is slidably sealed with the outer shell 1. It can be understood that the "slidably sealed fit between component A and component B" described in the text means that component A can be relatively displaced with component B under the action of an external force, and when component A is displaced relative to component B, the sliding mating surfaces of component A and component B remain sealed. The specific implementation method includes but is not limited to configuring component A and component B into a slidably fitted connection state, and then setting a sealing ring between the mating surfaces of component A and component B.

[0053] The piston 2 divides the interior of the outer shell 1 into a first chamber 11 and a second chamber 12. It can be understood that the first chamber 11 and the second chamber 12 are independent of each other, that is, the fluid in the first chamber 11 and the fluid in the second chamber 12 do not exchange with each other. Since the piston 2 is movable in the outer shell 1, during the movement, the internal spaces of the first chamber 11 and the second chamber 12 increase or decrease accordingly, and during the movement of the piston 2, the interiors of the first chamber 11 and the second chamber 12 remain independent.

[0054] The adjusting member 3 is elastically supported in the second chamber 12 by the elastic member 5, and a third chamber 30 is enclosed between the adjusting member 3 and the outer shell 1. The configuration of the third chamber 30 will be described in detail later and will not be repeated here. The locking member 4 is transmission-connected to the adjusting member 3, so that when the adjusting member 3 is actuated, the locking member 4 will be driven to actuate synchronously.

[0055] A flow path is also provided in the variable pitch device, which includes a first flow path 61 connected to the first chamber 11, a second flow path 62 connected to the second chamber 12, and a third flow path 63 connected to the third chamber 30. For example, fluid such as hydraulic oil can enter the first chamber 11, the second chamber 12 and the third chamber 30 respectively through the first flow path 61, the second flow path 62 and the third flow path 63, thereby changing the fluid pressure in the three chambers.

[0056] When the fluid pressure in the second chamber 12 is greater than the pressure threshold, the adjusting member 3 is driven to move in the direction of compressing the elastic member 5, that is, to move in the direction close to the elastic member 5, so that the elastic member 5 is compressed, and during the movement, the locking member 4 can be driven to move to the first position (that is, Figure 6 When the fluid pressure in the second chamber 12 is less than the pressure threshold, the elastic member 5 is elastically reset and can drive the adjusting member 3 to actuate, so that the adjusting member 3 drives the locking member 4 to move to the second position (i.e. Figure 4 In the state shown), the locking member 4 allows the piston 2 to move in the first position and restricts the movement of the piston 2 in the second position.

[0057] Through the above configuration, when the second chamber 12 leaks and the internal liquid pressure decreases, when it decreases to below the pressure threshold, the locking member 4 can be synchronously linked to move to the second position to lock the piston, thereby achieving one-way locking in the event of oil chamber leakage and preventing the propeller from moving in the flat propeller direction.

[0058] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0059] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0060] In some embodiments of the pitch control device, the pressure threshold is calculated by the following formula (1):

[0061]

[0062] Among them, p Bmin is the pressure threshold, f max is the maximum pressure of the elastic member 5 within the compression stroke, S b is the cross-sectional area of ​​the third chamber 30; p 0 is the oil pressure in the third chamber.

[0063] In some embodiments of the pitch control device, the outer shell 1 includes an outer cylinder wall 13 and a center rod 14 disposed in the outer cylinder wall 13, and the piston 2 includes a piston portion 20, a sleeve portion 21 and a matching portion 22, and the sleeve portion 21 and the matching portion 22 are respectively disposed on both sides of the piston portion 20 along the axial direction a. As shown in the figure, the piston portion 20 is sleeved on the outer side of the center rod 14 and is slidably sealed with the center rod 14, the piston portion extends from the sleeve portion 21 toward the outer side of the radial direction b, and is slidably sealed with the outer cylinder wall 13, and the matching portion 22 is disposed in the second chamber 12, and in the second position, as shown in FIG. Figure 4 As shown, the locking member 4 abuts against the matching portion 22 to limit the movement of the piston 2. Figure 6 As shown, there is a gap between the locking member 4 and the matching portion 22 to allow the piston 2 to move. Specifically, the matching portion 22 can be a sleeve-shaped ring arranged around the locking member 4 and the outer periphery of the adjusting member 3 as shown in the figure, and the locking member 4 abuts against the inner periphery of the matching portion 22 to lock by the friction between the two.

[0064] In some embodiments of the pitch control device, the adjusting member 3 is sleeved on the outer periphery of the center rod 14, the elastic member 5 is a coil spring sleeved on the outer periphery of the center rod 14, and the locking member 4 is a cam hinged to the outer side of the center rod 14. The adjusting member 3 has a connecting opening 31, the cam has a rod portion 41, and a first convex portion 311 and a second convex portion 312 are arranged in the connecting opening 31. When the adjusting member 3 moves in the direction of compressing the elastic member 5, the first convex portion 311 cooperates with the rod portion 41 to make the locking member 4 rotate along the first direction x1, so that the locking member 4 at the first position can move to the second position, as shown in FIG. Figure 5 As shown, in the second position, the second protrusion 312 contacts the rod 41. When the adjusting member 3 moves in a direction away from the elastic member 5, the second protrusion 312 cooperates with the rod 41 to make the locking member 4 rotate along the second direction x2, so that the locking member 4 at the second position can move to the first position. Figure 8As shown, in the first position, the first protrusion 311 contacts the rod 41. In the first position and the second position, the first protrusion 311 and the second protrusion 312 restrict the rod 41 from coming out. The first direction x1 is opposite to the second direction x2. Specifically, when the first protrusion 311 moves from the shaft of the rod 41 toward the end of the rod 41, the locking member 4 can be driven to rotate. When the second protrusion 312 moves from the end of the rod 41 toward the shaft of the rod 41, the locking member 4 can also be driven to rotate. In a specific embodiment, the first protrusion 311 and the second protrusion 312 are both spherical protrusions to achieve the movement of the rod 41 through the arc outer surface. The above arrangement can achieve one-way locking of the piston with a simple configuration.

[0065] In a specific embodiment, a cam seat 48 is provided on the outer side of the central rod 14 , and the locking member 4 is hinged to the outer periphery of the central rod 14 via the cam seat.

[0066] It is understandable that in some other embodiments different from those shown in the figures, the locking member may also be other structural forms such as a plug composed of two sliding blocks with matching inclined surfaces.

[0067] In some embodiments of the pitch control device, the connection opening 31 has an inner annular wall 313 and an outer annular wall 314, the inner annular wall 313 protrudes toward the locking member 4 relative to the outer annular wall 314, the first convex portion 311 is arranged in the portion of the inner annular wall 313 protruding from the outer annular wall 314, and is protruded toward the connection opening 31, and the second convex portion 312 is arranged at the end of the outer annular wall 314, and is protruded toward the connection opening 31. A first step portion 81 is arranged on the center rod 14, and a second step portion 82 is arranged on the outer side of the outer annular wall 314. When the adjusting member 3 moves along the center rod 14 toward the direction of the compression elastic member 5, the first step portion 81 can abut against the second step portion 82 to limit the continued movement of the adjusting member 3. In the second position, the first step portion 81 abuts against the second step portion 82 , and when the locking member 4 moves between the first position and the second position, at least a portion of the rod portion 41 contacts the second protrusion 312 to prevent the rod portion 41 from completely escaping from the connecting opening 31 .

[0068] In some embodiments of the pitch device, the center rod 14 has a first rod segment 141 and a second rod segment 142, the outer diameter of the first rod segment 141 is smaller than the outer diameter of the second rod segment 142, so as to form a first step portion 81 between the first rod segment 141 and the second rod segment 142. The outer annular wall 314 includes a first annular wall segment 3141 and a second annular wall segment 3142, the inner diameter of the first annular wall segment 3141 is smaller than the inner diameter of the second annular wall segment 3142, so as to form a second step portion 82 between the first annular wall segment 3141 and the second annular wall segment 3142. Among them, a convex ring portion 3143 convexly arranged toward the inner side of the radial direction b is further provided on the side of the first ring wall segment 3141 away from the second ring wall segment 3142. In the assembled state, the convex ring portion 3143 and the first rod segment 141 can be slidably sealed and matched, and the second ring wall segment 3142 and the second rod segment 142 can be slidably sealed and matched. The inner diameter of the first ring wall segment 3141 is larger than the outer diameter of the first rod segment 141, but smaller than the outer diameter of the second rod segment 142. The axial sides of the third chamber 30 are defined by the convex ring portion 3143 and the first step portion 81, and the radial sides are defined by the outer ring wall 314 and the first rod segment 141. It can be understood that when located in the first position, the first ring wall segment 3141 and the first rod segment 141 define the wall surfaces on the radial sides of the third chamber 30, and when located in the second position, the first ring wall segment 3141, the second ring wall segment 3142 and the first rod segment 141 define the wall surfaces on the radial sides of the third chamber 30 together.

[0069] In some embodiments of the pitch control device, in the second position, such as Figure 4 As shown, the mating surface 400 of the cam abuts against the mating portion 22 to limit the movement of the piston 2. The mating surface 400 is an arc surface, and the line connecting the center O1 of the circle where the arc surface extends and the rotation center O2 of the cam is parallel to the axial direction a of the center rod 41. This configuration allows the locking member 4 to be in stable contact with the piston 2 to avoid damage to the locking member 4 under impact load. In a specific embodiment, the contact surface between the locking member 4 and the piston 2 is set to a rough surface to increase the friction coefficient between the two.

[0070] In some embodiments of the pitch control device, when the mating surface 400 abuts against the mating portion 22, along the axial direction a of the center rod 41, there is a first distance l between the abutment point between the mating surface 400 and the mating portion 22 and the rotation center O2, and along the radial direction b of the center rod 41, there is a second distance h between the rotation center O2 and the mating portion 22, and the first distance l and the second distance h satisfy the following relationship (2):

[0071] μh>l (2);

[0072] Wherein, μ is the friction coefficient between the mating portion 22 and the mating surface 400. Through the above configuration, friction self-locking can be generated between the mating surface 400 and the mating portion 22 to prevent the movement of the piston 2, so that when the torque of the propeller fan applied by the external load is in the direction of small pitch, the propeller fan will be locked at the current position under the action of the pitch-changing device; when the torque of the propeller fan applied by the external load is in the direction of large pitch, the propeller fan will move in the direction of large pitch, further reducing the resistance caused to the engine.

[0073] In some embodiments of the pitch control device, the first flow path 61 , the second flow path 62 , and the third flow path 63 are opened in the central rod 41 .

[0074] On the other hand, according to some embodiments of the present application, a turboprop engine is also provided, which includes a propeller and a pitch-changing device as described in one or more of the previous embodiments. A shift fork 7 is provided on the piston 2, and the propeller is connected to the piston through the shift fork 7. In a specific embodiment, the piston 2 has a shoulder, and the shift fork 7 is pressed against the shoulder of the piston 2 through a clamping nut 71.

[0075] In a specific embodiment, the first cavity 11 is a small-pitch oil cavity, and the second cavity 12 is a large-pitch oil cavity. When the pitch of the fan blades needs to be adjusted toward a small pitch, it is achieved by increasing the fluid pressure in the first cavity 11. When the pitch of the fan blades needs to be adjusted toward a large pitch, it is achieved by increasing the fluid pressure in the second cavity 12.

[0076] The adjustment process according to some embodiments of the pitch control device is as follows:

[0077] Pitch adjustment process:

[0078] When adjusting to a larger distance, the second chamber 12 is pressurized, driving the adjusting member 3 to move rightward, and the lower end of the adjusting member 3 contacts the locking member 4, driving the locking member 4 to rotate and separate from the piston 2, releasing the one-way locking state. Figure 4 At the same time, the oil pressure in the second chamber 12 drives the piston 2 to move to the right, driving the shift fork 7 to drive the propeller fan to rotate in the direction of the maximum pitch.

[0079] When the distance is adjusted to a smaller value, the pressure in the second chamber 12 decreases but is still greater than p Bmin (See formula (1)), but at this time the oil pressure p B The size p is generated on the adjusting element 3 B ·S b The pressure is still greater than the maximum pressure in the compression stroke of the spring 3, driving the adjusting member 3 to move rightward, and the first convex portion 311 at the lower end of the adjusting member 3 contacts the locking member 4, driving the locking member 4 to rotate and separate from the piston 2, releasing the one-way locking state. Figure 4At the same time, the oil pressure in the second cavity 11 drives the piston 2 to move to the left, driving the shift fork 7 to drive the propeller fan to rotate in the direction of the small pitch.

[0080] Pitch one-way locking process:

[0081] When a large leakage occurs in the second cavity 12, the internal oil pressure p B Rapidly less than p Bmin When the spring 5 drives the adjusting member 3 to move to the left, the second protrusion 312 on the upper end of the adjusting member 3 contacts the locking member 4, driving the locking member 4 to move until the locking member 4 hits the piston 2, and the two generate contact positive pressure.

[0082] When the torque of the propeller fan caused by the external load is in the direction of small pitch, the propeller fan will be locked in the current position under the action of the locking member 4, as shown in the attached Figure 2 As shown; when the torque of the propeller fan caused by the external load is in the direction of long pitch, the propeller fan will move in the direction of long pitch, further reducing the resistance caused to the engine.

[0083] Other processes:

[0084] When the seal of the first cavity 11 fails and the second cavity 12 still works normally, the oil pressure p B Still greater than p Bmin , driving the adjusting member 3 to move rightward, the first convex portion 311 at the lower end of the adjusting member 3 contacts the locking member 4, driving the locking member 4 to rotate and separate from the piston 2, releasing the one-way locking state, as shown in the attached Figure 4 As shown; at the same time, piston 2 is under oil pressure p B Under this action, it will move in the direction of large pitch, causing the propeller to straighten the propeller and ensure the safe operation of the engine.

[0085] The pitch-changing device of this configuration uses the oil pressure and spring of the second cavity 12 to drive the adjusting member 3, controls the contact state of the locking member 4 and the piston 2, and realizes one-way locking in the case of leakage of the large-pitch oil cavity to prevent the propeller from moving in the flat-paddle direction. At the same time, the mechanism for realizing one-way locking only includes four parts: the spring, the adjusting member 3, the locking member 4, and the cam. It has a simple structure and is easy to process, and can effectively improve the reliability of the pitch-changing actuator with the locking mechanism.

[0086] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0087] It should be understood that the two directions mentioned in the text are "parallel" and the like, etc. do not need to meet strict angle requirements in the mathematical sense, but allow a certain tolerance range, for example, the angle is within 5° compared to the angle required in the mathematical sense, and "along" a certain direction means that there is at least a component in that direction, preferably, the angle with that direction is within 10°, and more preferably, the angle is within 5°.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A pitch control device, characterized in that: include: outer shell; A piston is disposed in the outer shell and is slidably and sealingly matched with the outer shell to separate the interior of the outer shell into a first chamber and a second chamber; The adjusting member is elastically supported in the second chamber by the elastic member, and a third chamber is enclosed between the adjusting member and the outer shell; A locking member drivingly connected to the adjusting member; and a flow path, comprising a first flow path communicating with the first chamber, a second flow path communicating with the second chamber, and a third flow path communicating with the third chamber; When the fluid pressure in the second chamber is greater than a pressure threshold, the adjusting member is driven to move in the direction of compressing the elastic member, and can drive the locking member to move to the first position; when the fluid pressure in the second chamber is less than the pressure threshold, the elastic member can elastically reset and drive the adjusting member to actuate, so that the adjusting member drives the locking member to move to the second position; the locking member allows the piston to move in the first position, and restricts the piston movement in the second position.

2. The pitch device according to claim 1, characterized in that: The pressure threshold is calculated by the following formula (1): Among them, p Bmin is the pressure threshold, f max is the maximum pressure within the compression stroke of the elastic member, S b is the cross-sectional area of ​​the third chamber, and p0 is the oil pressure of the third chamber.

3. The pitch device according to claim 1, characterized in that: The outer shell includes an outer tube wall and a center rod arranged in the outer tube wall, and the piston includes a piston part, a sleeve part and a matching part. The piston part is sleeved on the outside of the center rod and is slidably sealed with the center rod. The piston part extends radially outward from the sleeve part and is slidably sealed with the outer tube wall. The matching part is arranged in the second chamber. In the second position, the locking member abuts against the matching part to limit the movement of the piston.

4. The pitch device according to claim 3, characterized in that: The adjusting member is sleeved on the outer periphery of the central rod, the elastic member is a coil spring sleeved on the outer periphery of the central rod, and the locking member is a cam hinged on the outer side of the central rod; The adjusting member has a connecting opening, the cam has a rod portion, and a first convex portion and a second convex portion are arranged in the connecting opening; When the adjusting member moves in a direction to compress the elastic member, the first protrusion cooperates with the rod portion to make the locking member rotate along the first direction, so that the locking member located at the first position can move to the second position; When the adjusting member moves in a direction away from the elastic member, the second protrusion cooperates with the rod portion to make the locking member rotate along the second direction, so that the locking member located at the second position can move to the first position; The first direction is opposite to the second direction.

5. The pitch control device according to claim 4, characterized in that: The connecting opening has an inner annular wall and an outer annular wall, the inner annular wall protrudes toward the locking member relative to the outer annular wall, the first protrusion is arranged in a portion of the inner annular wall protruding from the outer annular wall and protrudes toward the connecting opening, and the second protrusion is arranged at an end of the outer annular wall and protrudes toward the connecting opening; The center rod is provided with a first step portion, and the outer side of the outer ring wall is provided with a second step portion. When the adjusting member moves along the center rod in a direction to compress the elastic member, the first step portion can abut against the second step portion to limit the continued movement of the adjusting member. Wherein, in the second position, the first step portion abuts against the second step portion, and when the locking member moves between the first position and the second position, at least a portion of the rod portion contacts the second protrusion.

6. The pitch device according to claim 5, characterized in that: The central rod comprises a first rod segment and a second rod segment, wherein the outer diameter of the first rod segment is smaller than the outer diameter of the second rod segment, so as to form the first step portion between the first rod segment and the second rod segment; The outer annular wall comprises a first annular wall segment and a second annular wall segment, wherein the inner diameter of the first annular wall segment is smaller than the inner diameter of the second annular wall segment, so as to form the second step portion between the first annular wall segment and the second annular wall segment; Among them, a convex ring portion convexly arranged toward the radial inner side is further provided on a side of the first annular wall segment away from the second annular wall segment. In the assembled state, the convex ring portion and the first rod segment are slidably sealed and matched, and the second annular wall segment and the second rod segment are slidably sealed and matched. The inner diameter of the first annular wall segment is larger than the outer diameter of the first rod segment, but smaller than the outer diameter of the second rod segment. The axial sides of the third chamber are defined by the convex ring portion and the first step portion, and the radial sides are defined by the outer annular wall and the first rod segment.

7. The pitch control device according to claim 4, characterized in that: In the second position, the mating surface of the cam abuts against the mating portion to limit the movement of the piston; Wherein, the matching surface is an arc surface, and a line connecting the center of a circle where the arc surface extends and the rotation center of the cam is parallel to the axial direction of the center rod.

8. The pitch control device according to claim 7, characterized in that: When the mating surface abuts against the mating portion, along the axial direction of the center rod, there is a first distance between the abutment point between the mating surface and the mating portion and the rotation center, and along the radial direction of the center rod, there is a second distance between the rotation center and the mating portion, and the first distance and the second distance satisfy the following relationship (2): μh>l (2); Wherein, l is the first distance, h is the second distance, and μ is the friction coefficient between the matching portion and the matching surface.

9. The pitch control device according to claim 3, characterized in that: The first flow path, the second flow path, and the third flow path are opened in the center rod.

10. A turboprop engine, characterized in that: A propeller fan comprising a propeller fan and a pitch-changing device as claimed in any one of claims 1 to 9; Wherein, a shift fork is arranged on the piston, and the propeller fan is transmission-connected to the piston via the shift fork.

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