CN111268119A

CN111268119A - Helicopter rotor pitch rod, helicopter automatic tilter and helicopter

Info

Publication number: CN111268119A
Application number: CN202010095946.6A
Authority: CN
Inventors: 倪明; 李朝阳; 郑怡华
Original assignee: Shanghai Shenjia Aviation Technology Co ltd
Priority date: 2020-02-17
Filing date: 2020-02-17
Publication date: 2020-06-12

Abstract

One object of the present invention is to provide a pitch horn for a helicopter rotor that allows to achieve a reduction in the dry weight of the helicopter. It is another object of the present invention to provide an automatic helicopter tilter that includes the aforementioned helicopter rotor pitch horn. It is a further object of the present invention to provide a helicopter including the helicopter automatic tilter described above. To achieve the above object, a helicopter rotor pitch control rod comprises an outer cylinder, and a piezoelectric unit, a piston head, a liquid storage part, a check valve, a reversing valve, an energy accumulator, a hydraulic cylinder and a connecting piece which are arranged in the outer cylinder. The upper part and the lower part of the cylinder barrel are respectively communicated with the reversing valve through the first pipe fitting and the second pipe fitting, hydraulic liquid respectively flows to two axial sides of the piston rod through the first pipe fitting and the second pipe fitting, and the reversing valve respectively controls the first pipe fitting, the second pipe fitting and the first cavity to be communicated or closed, so that the piston rod is driven to move by the hydraulic liquid.

Description

Helicopter rotor pitch rod, helicopter automatic tilter and helicopter

Technical Field

Helicopter rotor pitch horn, helicopter automatic tilter and helicopter.

Background

Helicopter automatic tillers are a key component of helicopter control systems that transmit control signals and control power inputs to the pitch-varying motion of the helicopter rotor blades. It has a rotating frame connected to a straight rotor system, wherein: one end of the hydraulic actuator is connected to the rotating frame and the other end of the hydraulic actuator is connected to the pitch hinges of the rotor blades. The pitch motion changes the angle of attack of the blades, thereby controlling the amount of lift generated on each blade. By manipulating the pitch angle of the rotor blades using a swashplate, the amount and direction of lift generated by the rotor may be controlled. The magnitude of the rotor lift is determined by a collective control that simultaneously alters the angle of attack of all the blades. The periodic input controls the direction of thrust by sinusoidally varying the pitch angle.

The pitch rod assembly in the traditional automatic inclinator is driven by a centralized hydraulic system, and the inventor finds that the traditional centralized hydraulic power system has huge part number and system weight; such as a fuel tank, a fuel filter, piping, an accumulator, a heater, a cooler, etc. Thus, in helicopter flight control systems, the hydraulic system is a major component of the helicopter's dry weight (deadweight). Due to the numerous components of the system, the probability of failure is also relatively high. It is therefore desirable to provide a new helicopter auto-tilter to reduce helicopter dry weight.

Disclosure of Invention

One object of the present invention is to provide a pitch horn for a helicopter rotor that allows to achieve a reduction in the dry weight of the helicopter.

Another object of the present invention is to provide an automatic helicopter tilter that can be driven electrically and without relying on a mechanical hydraulic system, comprising the aforementioned helicopter rotor pitch horn.

It is a further object of the present invention to provide a helicopter including the helicopter automatic tilter described above.

For realizing the helicopter rotor displacement pole of aforementioned one purpose, including outer barrel, outer barrel one end is the blind end, and the other end is open end, the blind end sets up to first connecting portion be provided with in the outer barrel:

the piezoelectric unit is supported on the inner side of the closed end and is driven by an external power supply unit to generate vibration;

the piston head is in transmission connection with the piezoelectric unit;

the liquid storage part is provided with a first cavity, hydraulic liquid is stored in the first cavity, the inlet side of the liquid storage part is provided with an opening allowing the piston head to enter, and the outlet side of the liquid storage part is provided with a backflow hole and a liquid outlet hole;

the check valve is arranged at the backflow hole and the liquid outlet hole;

the reversing valve is communicated with the outlet of the check valve;

the energy accumulator is provided with a second cavity, is communicated with the backflow hole and is used for temporarily storing the hydraulic fluid which flows back to the first cavity;

the hydraulic cylinder comprises a cylinder barrel and a piston rod, and the piston rod can move in the cylinder barrel; and the number of the first and second groups,

the connecting piece is provided with a second connecting part and is driven by the piston rod to extend out of or retract into the open end;

the upper portion and the lower portion of the cylinder barrel are respectively communicated with the reversing valve through a first pipe fitting and a second pipe fitting, hydraulic liquid respectively flows to two axial sides of the piston rod through the first pipe fitting and the second pipe fitting, and the reversing valve respectively controls the first pipe fitting, the second pipe fitting and the first cavity to be communicated or closed, so that the piston rod is driven to move by the hydraulic liquid.

In one or more embodiments, the hydraulic cylinder is supported at both ends by linear bearings, respectively.

In one or more embodiments, the linear bearing is made of 100Cr6 bearing steel.

In one or more embodiments, a support device is provided in the outer cylinder, and the piezoelectric unit is supported by the support device;

wherein the support device is made of beryllium alloy.

In one or more embodiments, the piezoelectric element and the support device are connected by a fastener made of a tungsten alloy.

In one or more embodiments, an LVDT sensor is disposed on the piston rod.

In one or more embodiments, a diaphragm is disposed between a piston head and the piezoelectric unit, an inlet side of the first cavity being closed by the diaphragm;

wherein the diaphragm transmits the vibration generated by the piezoelectric unit to the piston head.

In one or more embodiments, a sealing ring is disposed between an end surface of the diaphragm and the piezoelectric unit and between the end surface of the diaphragm and the end surface of the first cavity, respectively.

In one or more embodiments, the diaphragm is made of 301 stainless steel.

In one or more embodiments, the first cavity is made of beryllium alloy.

In one or more embodiments, the piston head is made of an aluminum alloy.

In one or more embodiments, the cylinder barrel and the piston rod are made of a titanium alloy.

In one or more embodiments, the directional valve is a three-position, five-way electromagnetic directional valve.

In one or more embodiments, the valve spool of the reversing valve is made of an aluminum alloy with a teflon coating.

In one or more embodiments, the accumulator further comprises an elastic diaphragm enclosing the second cavity, the elastic diaphragm being made of 301 stainless steel.

In one or more embodiments, the outer cylinder is made of a titanium alloy.

In one or more embodiments, the first and second tube members are made of beryllium alloy.

The helicopter automatic tilter for achieving the other purpose comprises a helicopter blade, a hub and a variable-pitch rod connecting the helicopter blade and the hub, wherein the variable-pitch rod is a helicopter rotor variable-pitch rod as described above;

the helicopter tilter is provided with a plurality of blades, and each blade is connected with the hub through the helicopter rotor pitch-changing rod.

To achieve the aforementioned further object, a helicopter automatic tilter as described above is employed.

The invention has the advantages that the piezoelectric unit is used as the driving unit in the variable pitch rod of the helicopter rotor wing, the traditional centralized hydraulic system can be replaced, and compared with the centralized hydraulic system, the piezoelectric unit can get rid of the dependence on the centralized hydraulic system, greatly reduce the dry weight of the helicopter and realize the electric power of the action executing mechanism of the flight control system.

Drawings

The above and other features, properties and advantages of the present invention will become more apparent from the following description of the embodiments with reference to the accompanying drawings, in which:

FIG. 1 illustrates a perspective view of one embodiment of a helicopter rotor pitch horn;

FIG. 2 is a schematic sectional view taken along the line A-A in FIG. 1;

FIG. 3 shows an exploded view of the outer barrel mid-section subassembly;

FIG. 4 shows an exploded view of the other components in the outer barrel;

FIG. 5 shows a structural schematic view of various components in the outer cylinder;

FIG. 6 is a schematic diagram of the components in the outer cylinder in a first actuation state;

FIG. 7 is a schematic diagram of the components in the outer cylinder in a second actuation state;

FIG. 8 is a schematic view of the components of the outer barrel in a third actuated state;

FIG. 9 is a schematic diagram of the components in the outer cylinder in a fourth operating state;

FIG. 10 illustrates a schematic perspective view of one embodiment of an automatic recliner;

FIG. 11 is a schematic perspective view of another embodiment of an automatic recliner;

FIG. 12 illustrates a cross-sectional view of one embodiment of a check valve;

FIG. 13 is an exploded view of the check valve in half section;

FIG. 14 illustrates a perspective view of one embodiment of a linear bearing;

FIG. 15 illustrates a perspective view of an embodiment of an accumulator;

FIG. 16 is a schematic cross-sectional view taken along line B-B of FIG. 15;

fig. 17 is an exploded view of the accumulator in a half-section state.

Detailed Description

The following discloses many different embodiments or examples for implementing the subject technology described. Specific examples of components and arrangements are described below to simplify the present disclosure, but these are merely examples and are not intended to limit the scope of the present disclosure. For example, if a first feature is formed over or on a second feature described later in the specification, this may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features are formed between the first and second features, such that the first and second features may not be in direct contact. Additionally, reference numerals and/or letters may be repeated among the various examples throughout this disclosure. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. Further, when a first element is described as being coupled or coupled to a second element, the description includes embodiments in which the first and second elements are directly coupled or coupled to each other, as well as embodiments in which one or more additional intervening elements are added to indirectly couple or couple the first and second elements to each other.

It should be noted that, where used, the following description of upper, lower, left, right, front, rear, top, bottom, positive, negative, clockwise, and counterclockwise are used for convenience only and do not imply any particular fixed orientation. In fact, they are used to reflect the relative position and/or orientation between the various parts of the object.

It is noted that these and other figures which follow are merely exemplary and not drawn to scale and should not be considered as limiting the scope of the invention as it is actually claimed. Further, the conversion methods in the different embodiments may be appropriately combined.

Fig. 1 is a perspective view of an embodiment of a helicopter rotor pitch post 1, and fig. 2 is a cross-sectional view of fig. 1 taken along a-a, please refer to fig. 1 and fig. 2 in combination. The helicopter rotor pitch control rod comprises an outer cylinder body 11 which is of a cylindrical structure, one end 11a of the outer cylinder body is closed, the other end 11b of the outer cylinder body is open, and a first connecting part 111 is arranged at the closed end 11a of the outer cylinder body 11.

A plurality of components constituting the pitch change lever are provided inside the outer cylinder 11, wherein fig. 3 shows an exploded view of the components located at an end of the outer cylinder 11 near the closed end 11a, fig. 4 shows an exploded view of the components located at an end of the outer cylinder 11 near the open end, and fig. 5 schematically shows the structure of each component inside the outer cylinder. Referring to fig. 2 to 5, the piezoelectric unit 12, the piston head 13, the reservoir 14, the check valve 15, the direction switching valve 16, the accumulator 17, the hydraulic cylinder 18, and the connecting member 19 are disposed in the outer cylinder 11.

The piezoelectric unit 12 is supported inside the closed end 11a, may be a piezoelectric stack, and may be driven by an external power supply unit to generate vibrations. Specifically, the piezoelectric unit 12 may include a plurality of piezoelectric elements 121 as shown in the figure, and when a power is applied to two ends of the piezoelectric element 121, the piezoelectric element 121 may be bent and deformed under the action of an electric field, and a piezoelectric stack formed by stacking the plurality of piezoelectric elements 121 may vibrate. It will be understood that the external power supply unit referred to herein is not shown, and may be an external energy storage device such as a battery, etc., and may be connected to the piezoelectric unit by a wired electrical connection or a wireless electrical connection.

The piston head 13 is arranged on the upper side of the piezoelectric unit 12 and is in transmission connection with the piezoelectric unit 12, namely when the piezoelectric unit 12 generates vibration, the piston head 13 is carried to vibrate together.

The reservoir 14 has a first chamber 140, and hydraulic fluid is stored in the first chamber 140. Here, the liquid reservoir 14 is provided with an inlet side 14a and an outlet side 14b on both upper and lower sides in the direction shown in the drawing. The inlet side 14a has an opening for allowing the piston head 13 to enter, and the outlet side 14b has a return hole 141 and a discharge hole 142. When piston head 13 vibrates, at least a portion of it enters first chamber 140, thereby allowing fluid within first chamber 140 to be forced and have a tendency to flow out of exit orifice 142.

The check valve 15 is disposed in the flow path at the return hole 141 and the outlet hole 142 at the outlet side 14b of the first chamber 140, and is used for limiting the hydraulic fluid flowing out of the first chamber 140 from the return hole 141 and the hydraulic fluid flowing into the first chamber 140 from the outlet hole 142.

The reversing valve 16 communicates with the outlet of the check valve 15 for receiving hydraulic fluid transferred from the check valve 15.

The accumulator 17 has a second chamber 170, which communicates with the return port 141, for temporarily storing the hydraulic fluid returning to the first chamber 140.

The hydraulic cylinder 18 comprises a cylinder tube 180 and a piston rod 181, the piston rod 181 being movable within the cylinder tube 180. The connecting member 19 has a second connecting portion 191, and when the piston rod 181 moves in the cylinder 180, the connecting member 19 is moved by the cylinder 180 to extend or retract into the open end 11b of the outer cylinder.

As shown in fig. 1 and 5, the upper and lower parts of the cylinder 11 are respectively communicated with the direction switching valve 16 through the first pipe 113 and the second pipe 114, and the hydraulic fluid flows to both sides of the piston rod 181 in the axial direction through the first pipe 113 and the second pipe 114, so as to push the piston rod 181 to move in the cylinder 180, specifically, as shown in fig. 1, the first pipe 113 is a lower part communicating the direction switching valve 16 with the cylinder 11, so as to be able to guide the hydraulic fluid to the lower side of the piston rod 181 in the axial direction, and the second pipe 114 is an upper part communicating the direction switching valve 16 with the cylinder 11, so as to be able to guide the hydraulic fluid to the upper side of the piston rod 181 in the axial direction. The first pipe member 113 and the second pipe member 114 are respectively communicated or closed by the direction valve 16 under different working conditions. For example, when the direction valve 16 is switched to an operating state in which the first pipe member 113 is open and the second pipe member 114 is closed, the high-pressure fluid flows from the first pipe member 113 to the lower side in the axial direction of the piston rod 181, and the piston rod 181 is pushed to move upward in the axial direction. When the direction valve 16 is switched to the working state in which the first pipe 113 is closed and the second pipe 114 is open, the high-pressure fluid flows from the second pipe 114 to the upper side of the piston rod 181 in the axial direction, and the piston rod 181 is pushed to move downward in the axial direction

Fig. 6 to 9 show schematic views in a plurality of states, respectively, when the drive piston rod 181 is moved.

First, as shown in fig. 6, the state is a compression state, when the piezoelectric unit 12 is electrified and vibrated, the piston head 13 presses the liquid in the first chamber 140, so that the hydraulic liquid in the first chamber 140 becomes a high-pressure liquid.

Subsequently, the state shown in fig. 7 is a liquid discharge state, in which the liquid pressure in the first chamber 140 is greater than the liquid pressure outside the check valve 15, so that the liquid in the first chamber 140 is discharged in the direction indicated by the arrow 101, guided by the direction change valve 16, and enters the cylinder 180, and the piston rod 181 is pushed to move by the high-pressure liquid. By switching the state of the reversing valve 16, the high-pressure liquid can flow to different directions of the piston rod 181, and the movement direction of the piston rod 181 can be controlled. Meanwhile, the low-pressure fluid outside the return hole 141 tends to flow back into the first cavity 140 along the return hole 141, and then enters into the accumulator 17 along the direction of the arrow 102.

In the state shown in fig. 8, the piezoelectric unit 12 is contracted, and the piston head 13 no longer presses the liquid in the first chamber 140, so that the pressure of the liquid in the first chamber 140 is reduced. Until, as shown in fig. 9, when the fluid pressure outside the return port 141 is greater than the fluid pressure in the first chamber 140, the check valve 15 at the return port 141 opens to allow fluid to flow from outside into the first chamber 140 as indicated by arrow 103, and hydraulic fluid in the accumulator 17 also flows from the accumulator as indicated by arrow 104. Due to the accumulator 17, the pressure of the returning fluid can be increased to increase the efficiency of the returning hydraulic fluid.

The helicopter rotor pitch bar 1 as described above can be applied in an automatic tilter as shown in fig. 10 to 11, which further comprises a helicopter blade 2 and a hub 3, the helicopter rotor pitch bar 1 being used to connect the blade 2 and the hub 3. Wherein, a plurality of blades 2 can be arranged on the helicopter tilter as shown in the figure, and each blade 2 is connected with a hub 3 through a helicopter rotor pitch rod 1.

It will be appreciated that the automatic tilter as described above may be employed in a helicopter.

By adopting the piezoelectric unit 12 as a driving unit in the helicopter rotor pitch-changing rod 1, the traditional centralized hydraulic system can be replaced, and compared with the centralized hydraulic system, the adoption of the piezoelectric unit 12 can get rid of the dependence on the centralized hydraulic system, greatly reduce the dry weight of the helicopter and realize the electric power of the action actuating mechanism of the flight control system. Through experimental verification and calculation, the total weight of the traditional centralized hydraulic system is about 496kg, while the weight of the alternative piezoelectric unit 12 serving as a driving sleeve driving device is only 54.96kg, so that the main blade control system of the helicopter can be reduced by 88.9% by using the helicopter rotor pitch rod 1 in the embodiment.

Meanwhile, each helicopter blade 2 is connected with a helicopter rotor pitch rod 1, and each blade 2 is subjected to attitude adjustment through the independent helicopter rotor pitch rods 1, so that the attitude control of a single blade 2 in the helicopter is realized, and the defect that the traditional automatic tilter can only realize linkage control of all blades is overcome.

While one embodiment of the present helicopter rotor pitch horn is described above, in other embodiments of the present helicopter rotor pitch horn the helicopter rotor pitch horn may have more details than the embodiments described above in many respects, and at least some of these details may vary widely. At least some of these details and variations are described below in several embodiments.

Fig. 12 shows a schematic cross-sectional view of an embodiment of the check valve 15, and fig. 13 shows an explosion view of the check valve 15 in a half-section. The check valve 15 includes a valve hole 150 and a check piston 151, wherein the check piston may be supported by a coil spring as shown in the figure and closes the valve hole 150, the check piston 151 allows a fluid having a certain pressure to enter and pass through the valve body in a forward direction, and specifically, when a liquid having a certain pressure is intended to flow in a direction a as shown in the figure, the check piston 151 is pressed, at this time, since an area of the check piston 151 located inside the valve body of the check valve 15 is larger than an area located outside the valve body of the check valve 15, so that the check piston 151 will move in the direction a and compress the coil spring, so that the valve hole 150 is opened, and the liquid can flow in from the valve hole. On the contrary, when the liquid is intended to flow in the direction opposite to the direction a as shown in the drawing, since the area of the check piston 151 located inside the valve body of the check valve 15 is larger than the area located outside the valve body of the check valve 15, the check piston 151 does not escape from the valve hole 150 in the direction opposite to the direction a, but continues to maintain the closed state of the valve hole 150. To ensure that fluid under pressure can only pass through the check valve 15 from a predetermined direction, preventing the back flow of hydraulic fluid within the hydraulic system in the present pitch lever.

With continued reference to fig. 4-5, in one embodiment of a pitch control lever for a helicopter rotor, the two ends of the hydraulic cylinder 18 are supported by linear bearings 182, and since the piston rod 181 moves back and forth at a higher frequency when the pitch control lever is operated, the frictional resistance generated by the axial movement can be effectively reduced by the support of the linear bearings 182. In which fig. 14 shows a perspective view of an embodiment of a linear bearing 182, the linear bearing 182 used in the present helicopter rotor pitch post may include a plurality of bearing portions 183 capable of rolling with respect to the axial direction of the supported member, and the plurality of bearing portions 183 may be a cylinder as shown in the figure or a sphere different from the one shown in the figure, such as a steel ball. Since the bearing section 183 is in point contact with the supported hydraulic cylinder 18, the use load is small, and the bearing section 183 rotates with a functional frictional resistance, so that the hydraulic cylinder 18 can be smoothly moved with high accuracy. The linear bearing 182 has an increased load but no sensitive change in coefficient of friction, so under heavy load, the coefficient of friction is very small, the long-term accuracy is maintained, the long-term maintenance of the mechanical service life is achieved, and the starting friction resistance and the dynamic friction resistance are very small due to point contact, so that energy can be saved, and a high movement speed can be easily achieved. In some embodiments, oil seals may be added to both sides of the linear bearing 182 to prevent foreign materials such as dust from entering.

In one embodiment of a helicopter rotor pitch horn, linear bearing 182 is made of 100Cr6 bearing steel.

In one embodiment of a helicopter rotor pitch horn, a support assembly 112 is disposed within the outer cylinder 11 and the piezoelectric unit 12 is supported by the support assembly. Wherein the support device 112 is made of beryllium alloy. Due to the characteristic of beryllium alloy having high specific stiffness, the support device 112 made of beryllium alloy can reduce deformation caused by vibration when the piezoelectric unit 12 vibrates at high frequency. Since the minimum displacement of the piezoelectric unit 12 generated during vibration is only about 10 μm, if the support device 112 cannot satisfy the characteristic of high specific stiffness, the support device 112 deforms during vibration of the piezoelectric unit 12, and the piezoelectric unit 12 fails to vibrate, and therefore, the support device 112 made of beryllium alloy can effectively achieve the purpose of driving by the piezoelectric unit 12.

In one embodiment of a helicopter rotor pitch horn, the connection between the support structure 112 and the piezoelectric unit 12 is via a fastener, including but not limited to a bolt fastener. Wherein the fastener is made of a tungsten alloy. Tungsten alloys are the best material for connectors due to their high yield strength characteristics.

In one embodiment of a helicopter rotor pitch control rod, piston rod 181 is provided with LVDT sensor 183 which can be used to measure elongation, vibrational frequency, amplitude, etc. of an object, and the amount of extension of piston rod 181 can be effectively monitored by providing LVDT sensor 183. In one embodiment, LVDT sensor 183 may be connected to an external power source and control unit, which receives the data monitored by LVDT sensor 183 to control the amount of extension of individual helicopter rotor mast 1.

In one embodiment of a helicopter rotor pitch bar, a diaphragm 131 is disposed between piston head 13 and piezoelectric unit 12. The inlet side 14a of the first chamber 140 is closed by a membrane 131, and the piston head 13 is supported and fixed on the membrane 131, and when the piezoelectric unit 12 is energized to generate vibration, the membrane 131 can transmit the vibration to the piston head to realize the transmission connection between the piston head 13 and the piezoelectric unit 12. Because the maximum stroke of the piston head 13 in the vibration process is 180 μm, the working frequency is 1000Hz, and the piston head 13 needs to meet the design requirement of ensuring the working life of at least 1000 hours, the traditional sealing device, such as a rubber ring, cannot meet the requirement of the working life. By sealing the inlet side 14a of the first chamber 140 with the diaphragm 131, the direct contact of the piston head 13 with the inner wall of the first chamber 140 is reduced while the above-mentioned working life is ensured, thereby reducing the frictional loss.

In one embodiment of the helicopter rotor pitch control rod, sealing rings 132 are respectively disposed between the upper and lower end surfaces of the diaphragm 131 and the piezoelectric unit 12 and between the end surfaces of the first cavity 140, so as to further ensure the sealing effect of the diaphragm 131 on the first cavity 140.

In one embodiment of a helicopter rotor pitch horn wherein the diaphragm 131 is made of 301 stainless steel, the fatigue limit of 301 stainless steel is 525MPa as determined by finite element analysis since the diaphragm 131 is required to meet the requirement of high life at high frequency vibration, the diaphragm 131 made of 301 stainless steel can reduce the occurrence of brittle cracks, thereby reducing fatigue failure.

In one embodiment of a helicopter rotor pitch horn, first cavity 140 is made of beryllium alloy, which is a characteristic of high specific stiffness, and thus first cavity 140 made of beryllium alloy can reduce deformation due to fluid pressure.

In one embodiment of a helicopter rotor pitch horn, piston head 13 is made of an aluminum alloy.

In one embodiment of the pitch horn of a helicopter rotor, the cylinder 180 and the piston rod 181 are made of titanium alloy, since during operation the cylinder 180 needs to bear a radial load of more than 3000N and the piston rod 181 needs to bear an axial load of more than 4000N, the titanium alloy has the characteristics of high strength, good corrosion resistance and high heat resistance, and the working life of the cylinder 180 and the piston rod 181 can be ensured in the above-mentioned working environment.

In one embodiment of a helicopter rotor pitch horn, the directional valve 16 is a three-position, five-way solenoid directional valve that is powered by an external power source to produce motion. In one embodiment, the directional valve 16 has its spool position controlled by the control unit to effect adjustment of the conduction/closure of the directional valve outlet.

In one embodiment of a helicopter rotor pitch horn, the reversing valve 16 comprises a magnet, a spool, and a coil wound around the ends of the spool. The valve core is made of aluminum alloy with a polytetrafluoroethylene coating, rapid reversing of the reversing valve 16 needs to be guaranteed when the reversing valve works, the aluminum alloy with the polytetrafluoroethylene coating has certain ductility while having lower surface hardness than magnets, and the service life under the working condition of high reversing frequency can be guaranteed.

Fig. 15 is a perspective view of an embodiment of the accumulator 17, fig. 16 is a cross-sectional view along the direction B-B in fig. 15, and fig. 17 is an exploded view of the accumulator in a half-section state. The accumulator 17 includes a second cavity 170 and an elastic diaphragm 171 for sealing the second cavity, and a hole 172 for communicating the second cavity 170 with the return hole 141 may be formed on a bottom surface of the second cavity 170. The accumulator 17 converts the excess pressure in the hydraulic system into elastic potential energy by means of the elastic diaphragm 171 for storage, and converts the elastic potential energy into hydraulic energy to be released for supplying the system again when the system needs. Wherein, the elastic diaphragm also needs to meet the requirement of having a long service life under the high-frequency vibration, and the material of the elastic diaphragm is 301 stainless steel after the finite element analysis test.

In one embodiment of a helicopter rotor pitch horn, the outer cylinder 11 is made of a titanium alloy that has the characteristics of high strength, good corrosion resistance, and high heat resistance, and is able to withstand the axial loads as well as the radial loads that occur during operation.

In one embodiment of the helicopter rotor pitch control rod, the first pipe 113 and the second pipe 114 are made of beryllium alloy, and since the first pipe 113 and the second pipe 114 are respectively used for conducting hydraulic fluid from the outlet of the reversing valve 16 to two axial sides of the piston rod 181 during operation, a large fluid pressure needs to be borne, if the pipes deform during fluid transmission, a pressure loss will be caused, and the pipe made of beryllium alloy with high specific rigidity can reduce the deformation.

Although the present invention has been disclosed in terms of the preferred embodiment, it is not intended to limit the invention, and variations and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention. Therefore, any modification, equivalent change and modification of the above embodiments according to the technical essence of the present invention are within the protection scope defined by the claims of the present invention, unless the technical essence of the present invention departs from the content of the present invention.

Claims

1. The utility model provides a helicopter rotor displacement pole, its characterized in that, includes outer barrel, outer barrel one end is the blind end, and the other end is open end, the blind end sets up to first connecting portion be provided with in the outer barrel:

the piston head is in transmission connection with the piezoelectric unit;

the check valve is arranged at the backflow hole and the liquid outlet hole;

the reversing valve is communicated with the outlet of the check valve;

2. A helicopter rotor pitch horn according to claim 1 wherein said hydraulic cylinder is supported at each end by a linear bearing.

3. A helicopter rotor pitch horn according to claim 2 wherein said linear bearing is made of 100Cr6 bearing steel.

4. A helicopter rotor pitch horn according to claim 1 wherein said outer cylinder has a support means disposed therein, said piezoelectric unit being supported by said support means;

wherein the support device is made of beryllium alloy.

5. A helicopter rotor pitch horn according to claim 4, wherein said piezoelectric unit and said support means are connected by a fastener, said fastener being made of a tungsten alloy.

6. A helicopter rotor pitch horn according to claim 1 wherein said piston rod is provided with an LVDT sensor.

7. A helicopter rotor pitch bar according to claim 1, wherein a diaphragm is disposed between a piston head and said piezoelectric unit, the inlet side of said first cavity being closed by said diaphragm;

8. A helicopter rotor pitch horn according to claim 7, wherein a seal is disposed between an end surface of said diaphragm and said piezoelectric element and between said end surface of said first cavity, respectively.

9. A helicopter rotor pitch mast according to claim 7, wherein said diaphragm is made of 301 stainless steel.

10. A helicopter rotor pitch horn according to claim 1, wherein said first cavity is formed from a beryllium alloy.

11. A helicopter rotor pitch horn according to claim 1 wherein said piston head is formed of an aluminum alloy.

12. A helicopter rotor pitch horn according to claim 1, wherein said cylinder and said piston rod are made of a titanium alloy.

13. A helicopter rotor pitch horn according to claim 1 wherein said directional control valve is a three-position, five-way electromagnetic directional control valve.

14. A helicopter rotor pitch horn according to claim 1 wherein said reversing valve spool is made of an aluminum alloy with a polytetrafluoroethylene coating.

15. A helicopter rotor pitch horn according to claim 1 wherein said accumulator further comprises an elastomeric diaphragm enclosing said second cavity, said elastomeric diaphragm being formed from 301 stainless steel.

16. A helicopter rotor pitch horn according to claim 1 wherein said outer cylinder is made of a titanium alloy.

17. A helicopter rotor pitch horn according to claim 1, wherein said first tubular member and said second tubular member are formed from a beryllium alloy.

18. A helicopter autorecliner comprising a helicopter blade, a hub and a pitch bar connecting said helicopter blade and said hub, wherein said pitch bar is a helicopter rotor pitch bar according to any one of claims 1 to 17;

19. A helicopter characterized by the use of an automatic helicopter tilter according to claim 18.