A variable collective pitch angle rotor test device in an icing wind tunnel

Abstract

A variable collective pitch angle rotor test device in an icing wind tunnel belongs to the technical field of icing wind tunnel tests. The invention aims to solve the problem that the variable pitch angle adjustment mechanism is easily stuck due to icing during icing wind tunnel tests. The device comprises a rotor main shaft and a variable pitch push rod, the variable pitch push rod is axially slidably matched with the upper part of the rotor main shaft, and the variable pitch push rod is circumferentially limited matched with the upper part of the rotor main shaft, the hub is arranged at the top end of the rotor main shaft, the roots of a plurality of blades are rotationally matched with the hub, the top end of the variable pitch push rod is sleeved with a variable pitch box, the variable pitch box is located in the hub, and a plurality of variable pitch sliding sleeves are slidingly arranged on the outer periphery of the variable pitch box, the crank comprises a circular plate body in the middle, a rocker is eccentrically arranged on one end face of the circular plate body, the other side of a plurality of cranks is plugged in one-to-one with the roots of a plurality of blades, the rockers of a plurality of cranks are hinged one-to-one with a plurality of variable pitch sliding sleeves, the built-in variable collective pitch mechanism is isolated from the airflow, and the variable collective pitch mechanism can be prevented from getting stuck or causing dynamic balance problems that affect the test results.

Description

Technical Field

[0001] The invention belongs to the technical field of icing wind tunnel tests, and in particular relates to an icing wind tunnel variable collective pitch angle rotor test device. Background Art

[0002] As a widely used method in aerodynamic research, wind tunnel testing provides necessary guarantees for the development of aviation, aerospace, rail transportation and other fields. The rotor is the main component used to provide lift for the helicopter. The icing of the rotor blades can cause blade vibration, increased torque, etc., which have a great impact on the safe flight of the helicopter. Compared with the flight test of the helicopter under real icing meteorological conditions, the study of the icing characteristics of the rotor through icing wind tunnel tests can greatly reduce the research cost and testing risk. The existing blade pitch angle adjustment mechanism of the icing wind tunnel is mostly exposed to low-temperature and high-humidity airflow. When conducting icing wind tunnel tests, it is easy to freeze and cause the pitch angle adjustment mechanism to become stuck. Summary of the invention

[0003] The purpose of the present invention is to provide an icing wind tunnel variable pitch angle rotor test device to solve the problem that the pitch angle adjustment mechanism is easily stuck due to icing during icing wind tunnel testing. The technical solution adopted by the present invention is as follows:

[0004] An icing wind tunnel variable pitch angle rotor test device comprises a plurality of blades, a rotor main shaft, a six-component balance, a base, a rotor motor, a variable pitch push rod, a bearing seat, a torque sensor, a crank and a variable pitch sliding sleeve;

[0005] The bearing seat, the six-component balance and the base are connected in sequence from top to bottom, the lower part of the rotor main shaft is rotationally matched with the bearing seat, the pitch-changing push rod is axially slidably matched with the upper part of the rotor main shaft, and the pitch-changing push rod is circumferentially limited with the upper part of the rotor main shaft, the lower end of the rotor main shaft passes through the six-component balance and is connected to one end of the torque sensor, the other end of the torque sensor is connected to the output shaft of the rotor motor through a commutator, a lifting mechanism is provided on the bearing seat, and the output end of the lifting mechanism is connected to the pitch-changing push rod;

[0006] The hub is arranged at the top end of the rotor main shaft, and a pitch change cavity is arranged in the hub. A plurality of connecting holes are arranged on the circumferential wall of the hub. The roots of a plurality of blades are rotatably matched with the plurality of connecting holes in a one-to-one correspondence. A square socket is arranged on the root end surface of the blade. A pitch change box is sleeved on the top end of the pitch change push rod. The pitch change box is located in the pitch change cavity. A plurality of sliding grooves are opened on the outer periphery of the pitch change box. A pitch change sleeve is slidably arranged in the sliding groove. The crank comprises a circular plate body in the middle, a square protrusion is arranged on one end surface of the circular plate body, and a rocker is eccentrically arranged on the other end surface of the circular plate body. The square protrusions of a plurality of cranks are plug-fitted with the square sockets of a plurality of blades in a one-to-one correspondence. The rockers of a plurality of cranks are hinged with a plurality of pitch change sleeves in a one-to-one correspondence, and the sliding groove is perpendicular to the corresponding blade.

[0007] Furthermore, the lower portion of the rotor main shaft is rotationally matched with the bearing seat through two main shaft bearings.

[0008] Furthermore, the pitch change box includes an upper piece and a lower piece of the pitch change box connected up and down, a plurality of slide grooves are opened on the outer periphery of the lower piece of the pitch change box, and the slide grooves penetrate the lower piece of the pitch change box upward, the upper piece of the pitch change box blocks the upper openings of the plurality of slide grooves, the top end of the pitch change push rod is provided with a double-sided milling flat section, the upper piece of the pitch change box and the lower piece of the pitch change box are sleeved on the double-sided milling flat section, the clamping ring is connected to the top end of the pitch change push rod, and the clamping ring presses the upper piece and the lower piece of the pitch change box onto the shoulder at the bottom of the double-sided milling flat section.

[0009] Furthermore, the hub is composed of an upper hub piece and a lower hub piece connected up and down.

[0010] Furthermore, a rotation speed encoder is provided on the base, and a measuring swivel of the rotation speed encoder is connected to the rotor main shaft.

[0011] Furthermore, an inner hole is provided at the upper portion of the rotor main shaft, and the pitch-changing push rod is slidably arranged in the inner hole of the rotor main shaft.

[0012] Furthermore, the lifting mechanism includes several electric cylinders, static ring pressure covers, static rings, dynamic rings, dynamic ring pressure covers and collective pitch adjustment bearings. Two transparent oblong holes are provided on the side walls of the inner hole of the rotor main shaft. The oblong holes are opened vertically. A push rod pin is provided at the bottom of the pitch change push rod. The static ring pressure cover and the static ring are clamped on both sides of the outer ring of the collective pitch adjustment bearing. The dynamic ring and the dynamic ring pressure cover are respectively clamped on both sides of the inner ring of the collective pitch adjustment bearing. The dynamic ring is sleeved on the rotor main shaft. The two ends of the push rod pin respectively pass through the two oblong holes and are connected to the dynamic ring. The push rod pin is slidably matched with the two oblong holes respectively. The rear cylinder head of the electric cylinder is connected to the bearing seat. A plurality of connecting ears are evenly arranged on the outer periphery of the static ring. The piston rods of several electric cylinders are connected to the plurality of connecting ears one by one.

[0013] Furthermore, two guide keys are arranged on the outer circumference of the rotor main shaft, and two key slots are vertically opened on the inner circumference of the moving ring, and the two guide keys are correspondingly slidably matched with the two key slots.

[0014] Furthermore, the bearing seat and the stationary ring are connected via an anti-torsion arm.

[0015] Furthermore, the electric cylinder is selected according to the thrust, and the thrust F of the electric cylinder is calculated by the following formula:

[0016] ;

[0017] Where:

[0018] A is the safety factor;

[0019] c is the effective distance between the blade lift action point and the blade root axis, in m;

[0020] S is the effective distance between the rocker and the blade root axis, in m;

[0021] μ is the friction coefficient when the pitch push rod moves up and down to adjust the blade collective pitch angle;

[0022] n is the number of electric cylinders;

[0023] T max is the maximum value of the rotor lift of several blades, in N;

[0024] In the hovering state, the rotor lift T of several blades is calculated as follows:

[0025] ;

[0026] is the blade tip loss coefficient;

[0027] is the number of blades;

[0028] is the rotation radius of the blade, in m;

[0029] 0.7 of the blade The lift coefficient of the airfoil at ;

[0030] is the air density, in kg / m 3 ;

[0031] is the blade chord length, in m;

[0032] is the rotor speed of the blade, in rad / s;

[0033] When the maximum lift coefficient is obtained, the total angle condition is calculated. The maximum value of T max .

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The present invention can measure the influence of blade icing on lift and torque under different rotor speeds and collective pitch angles. The variable collective pitch angle structure built into the rotor hub can greatly reduce the size of the rotor hub and effectively increase the test length of the test device in the blade extension direction. The variable collective pitch mechanism is built into the main shaft and the hub. When the test device is conducting an icing test, the built-in variable collective pitch mechanism is isolated from the airflow, so that icing will not occur, which can avoid the variable collective pitch mechanism from getting stuck or causing dynamic balance problems that affect the test results, thereby greatly improving the operational reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the overall structure of the patent of this invention;

[0037] Figure 2 yes Figure 1 AA section view;

[0038] Figure 3 yes Figure 2 A partial enlarged view of point C in the middle;

[0039] Figure 4 yes Figure 2 A partial enlarged view of point D in the middle;

[0040] Figure 5 yes Figure 1 BB cross-sectional view;

[0041] Figure 6 It is a schematic diagram of the connection between the pitch box and the blade;

[0042] Figure 7 It is a schematic diagram of the pitch change sleeve being slidably arranged on the pitch change box;

[0043] Figure 8 It is a schematic diagram of the structure of the blade;

[0044] Fig. 9 It is a schematic diagram of the structure of the crank.

[0045] In the figure, 1. blade, 2. upper blade of the hub, 3. lower blade of the hub, 4. rotor main shaft, 5. guide key, 6. static ring pressure cover, 7. static ring, 8. anti-torsion arm, 9. six-component balance, 10. base, 11. commutator, 12. rotor motor, 13. pitch change push rod, 14. electric cylinder, 15. bearing seat, 16. speed encoder, 17. coupling, 18. torque sensor, 19. dynamic ring pressure cover, 20. total pitch adjustment bearing, 21. dynamic ring, 22. push rod pin, 23. bearing pressure cover, 24. main shaft bearing, 25. locking nut, 26. blade bearing, 27. crank, 28. clamping ring, 29. upper blade of the pitch change box, 30. pitch change sleeve, 31. Variable pitch box lower plate, 32. slide groove, 33. square socket, 34. round plate, 35. square convex block, 36. rocker, 37. double-sided milling flat section. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is described below by the specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0047] The connection mentioned in the present invention is divided into fixed connection and detachable connection. The fixed connection is a non-detachable connection including but not limited to conventional fixed connection methods such as folding connection, rivet connection, bonding connection and welding connection. The detachable connection includes but not limited to conventional detachable methods such as bolt connection, snap connection, pin connection and hinge connection. When the specific connection method is not clearly defined, it is assumed that at least one connection method can be found in the existing connection methods to achieve the function, and those skilled in the art can choose according to their needs. For example: welding connection is selected for fixed connection, and bolt connection is selected for detachable connection.

[0048] The present invention will be further described in detail below in conjunction with the accompanying drawings. The following embodiments are provided to explain the present invention, but the present invention is not limited to the following embodiments.

[0049] Example: Figures 1 to 9 As shown, an icing wind tunnel variable pitch angle rotor test device includes a plurality of blades 1, a rotor main shaft 4, a six-component balance 9, a base 10, a rotor motor 12, a variable pitch push rod 13, a bearing seat 15, a torque sensor 18, a crank 27 and a variable pitch sliding sleeve 30;

[0050] The bearing seat 15, the six-component balance 9 and the base 10 are connected in sequence from top to bottom, the lower part of the rotor main shaft 4 is rotationally matched with the bearing seat 15, the pitch-changing push rod 13 is axially slidably matched with the upper part of the rotor main shaft 4, and the pitch-changing push rod 13 is circumferentially limited with the upper part of the rotor main shaft 4, the lower end of the rotor main shaft 4 passes through the six-component balance 9, and is connected to one end of the torque sensor 18, the other end of the torque sensor 18 is connected to the output shaft of the rotor motor 12 through the commutator 11, and a lifting mechanism is provided on the bearing seat 15, and the output end of the lifting mechanism is connected to the pitch-changing push rod 13;

[0051] The hub is arranged at the top end of the rotor main shaft 4, and a pitch-changing cavity is arranged in the hub. A plurality of connecting holes are arranged on the circumferential wall of the hub. The roots of a plurality of blades 1 are rotatably matched with the plurality of connecting holes in a one-to-one correspondence. A square plug hole 33 is arranged on the root end surface of the blade 1. A pitch-changing box is sleeved on the top end of the pitch-changing push rod 13. The pitch-changing box is located in the pitch-changing cavity. A plurality of sliding grooves 32 are opened on the outer periphery of the pitch-changing box. A pitch-changing sleeve 30 is slidably arranged in the sliding groove 32. The crank 27 includes a middle portion A circular plate body 34 is provided with a square protrusion 35 on one end surface of the circular plate body 34, and a rocker 36 is eccentrically provided on the other end surface of the circular plate body 34. The square protrusions 35 of the plurality of cranks 27 are plugged into and matched with the square sockets 33 of the plurality of blades 1 in a one-to-one manner, and the rockers 36 of the plurality of cranks 27 are hinged with the plurality of variable pitch sleeves 30 in a one-to-one manner. The slide groove 32 is perpendicular to the corresponding blade 1, and the slide groove 32 is located on one side of the corresponding blade 1, so that the variable pitch sleeve 30 slides horizontally close to or away from the corresponding blade 1.

[0052] The lower part of the rotor main shaft 4 is rotatably matched with the bearing seat 15 through two main shaft bearings 24. The bearing seat 15 is cylindrical. A locking nut 25 is provided on the rotor main shaft 4. The inner ring of the main shaft bearing 24 at the upper end is axially limited by a locking nut 25 and a shoulder of the rotor main shaft 4. Bearing covers 23 are provided at the upper and lower ends of the bearing seat 15. The outer ring of the main shaft bearing 24 at the upper end is axially limited by the bearing cover 23 at the upper end and the inner hole step of the bearing seat 15. The outer ring of the main shaft bearing 24 at the lower end is axially limited by the bearing cover 23 at the lower end and another inner hole step of the bearing seat 15. A spacer sleeve is sleeved on the rotor main shaft 4. One end of the spacer sleeve is abutted against the other shoulder of the rotor main shaft 4. The inner ring of the main shaft bearing 24 at the lower end is axially limited by another locking nut 25 and the other end of the spacer sleeve.

[0053] The pitch change box includes an upper piece 29 and a lower piece 31 connected up and down, a plurality of slide grooves 32 are opened on the outer periphery of the lower piece 31, and the slide grooves 32 penetrate upwardly through the lower piece 31, the upper piece 29 of the pitch change box blocks the upper openings of the plurality of slide grooves 32, and the top end of the pitch change push rod 13 is provided with a double-sided milled flat section 37, the inner holes of the upper piece 29 and the lower piece 31 of the pitch change box are adapted to the outer periphery of the double-sided milled flat section 37, the upper piece 29 and the lower piece 31 of the pitch change box are sleeved on the double-sided milled flat section 37, the clamping ring 28 is connected to the top end of the pitch change push rod 13, and the clamping ring 28 presses the upper piece 29 and the lower piece 31 of the pitch change box onto the shoulder at the bottom of the double-sided milled flat section 37.

[0054] The propeller hub is composed of a propeller hub upper plate 2 and a propeller hub lower plate 3 connected up and down, and the propeller hub lower plate 3 is engaged with the rotor main shaft 4 through screws.

[0055] A rotation speed encoder 16 is provided on the base 10 , and a measuring swivel of the rotation speed encoder 16 is connected to the rotor main shaft 4 so as to provide real-time feedback of the actual rotation speed of the rotor main shaft 4 .

[0056] An inner hole is provided at the upper portion of the rotor main shaft 4 , and the pitch change push rod 13 is slidably arranged in the inner hole of the rotor main shaft 4 .

[0057] The lifting mechanism includes several electric cylinders 14, static ring pressure covers 6, static rings 7, dynamic rings 21, dynamic ring pressure covers 19 and a total pitch adjustment bearing 20. Two transparent oblong holes are provided on the side wall of the inner hole of the rotor main shaft 4, and the oblong holes are opened vertically. A push rod pin 22 is provided at the bottom of the pitch change push rod 13. The static ring pressure cover 6 and the static ring 7 are clamped on both sides of the outer ring of the total pitch adjustment bearing 20, and the dynamic ring 21 and the dynamic ring pressure cover 19 are respectively clamped on both sides of the inner ring of the total pitch adjustment bearing 20. The dynamic ring 21 is sleeved on the rotor main shaft 4, and the two ends of the push rod pin 22 respectively pass through the two oblong holes and are connected to the dynamic ring 21. The push rod pin 22 is respectively slidably matched with the two oblong holes, the rear cylinder head of the electric cylinder 14 is connected to the bearing seat 15, and a plurality of connecting ears are evenly arranged on the outer periphery of the static ring 7. The piston rods of several electric cylinders 14 are upwardly connected to the plurality of said connecting ears one by one.

[0058] Two guide keys 5 are arranged on the outer periphery of the rotor main shaft 4, and two key slots are vertically provided on the inner periphery of the moving ring 21. The two guide keys 5 are correspondingly slidably fitted in the two key slots.

[0059] The bearing seat 15 and the stationary ring 7 are connected via an anti-torsion arm 8 .

[0060] The electric cylinder 14 is selected according to the thrust, and the thrust F of the electric cylinder 14 is calculated by the following formula:

[0061] ;

[0062] Where:

[0063] A is the safety factor;

[0064] c is the effective distance between the lift action point of blade 1 and the root axis of blade 1, in m;

[0065] S is the effective distance between the rocker 36 and the root axis of the blade 1, in m;

[0066] μ is the friction coefficient when the pitch push rod 13 moves up and down to adjust the total pitch angle of the blade 1;

[0067] n is the number of electric cylinders 14;

[0068] T max is the maximum value of the rotor lift of several blades 1, in N;

[0069] In the hovering state, the rotor lift T of several blades 1 is calculated as follows:

[0070] ;

[0071] is the blade tip loss coefficient;

[0072] is the number of blades 1;

[0073] is the rotation radius of blade 1, in m;

[0074] 0.7 of blade 1 The lift coefficient of the airfoil at ;

[0075] is the air density, in kg / m 3 ;

[0076] is the blade chord length, in m;

[0077] is the rotor speed of blade 1, in rad / s;

[0078] When the maximum lift coefficient is reached, the total angle condition with the maximum lift coefficient can be obtained. The maximum value of T max .

[0079] The test device is arranged in a wind tunnel. The aerodynamic force generated by the blade 1 rotating with the rotor main shaft 4 can be measured by a six-component balance 9 , and the required torque can be measured by a torque sensor 18 .

[0080] The push rod pin 22 on the pitch change push rod 13 and the oblong hole on the rotor main shaft 4 are slidably matched, so the pitch change push rod 13 and the rotor main shaft 4 can both slide vertically relative to each other and rotate together, the dynamic ring 21 is sleeved and matched with the rotor main shaft 4, and the static ring 7 and the dynamic ring 21 are rotatably connected through the total pitch adjustment bearing 20. Therefore, when the piston rods of several electric cylinders 14 are synchronously extended and retracted, the rotation of the pitch change push rod 13 and the rotor main shaft 4 can be kept unaffected, and several electric cylinders 14 can drive the pitch change push rod 13 to slide up and down to adjust the total pitch angle of several blades 1.

[0081] The pitch-changing push rod 13, the dynamic ring pressure cover 19, the dynamic ring 21, and the push rod pin 22 can rotate with the rotor main shaft 4; the top end of the pitch-changing push rod 13 extends into the pitch-changing cavity, and the root of the blade 1 rotates with the connecting hole through the blade bearing 26, and is limited by the hub upper plate 2 and the hub lower plate 3. The centrifugal force generated by the blade 1 rotating with the rotor main shaft 4 is borne by the blade bearing 26. During the rotation of the rotor main shaft 4, the pitch-changing push rod 13, the dynamic ring pressure cover 19, the dynamic ring 21, the push rod pin 22, the blade bearing 26, the crank 27, the clamping ring 28, the pitch-changing box upper plate 29, the pitch-changing sliding sleeve 30, and the pitch-changing box lower plate 31 rotate with the rotor main shaft 4, the outer ring of the total pitch adjustment bearing 20 does not rotate, the inner ring rotates, and the static ring pressure cover 6 and the static ring 7 do not rotate;

[0082] The test device of the present invention may not be provided with the commutator 11 according to actual needs.

[0083] The rotor motor 12 drives the rotor main shaft 4 to rotate through the torque sensor 18, and then drives the pitch push rod 13 and a plurality of blades 1 to rotate together, so that the wind tunnel rotor test can be carried out. The crank 27, the pitch sleeve 30, the pitch box and the pitch push rod 13 constitute a variable total pitch mechanism. The lifting mechanism can drive the pitch push rod 13 to slide up and down. At the same time, the lifting mechanism does not affect the rotation of the rotor main shaft 4 and the pitch push rod 13. The sliding of the pitch push rod 13 can drive a plurality of pitch sleeves 30 to move up and down. Since the rocker 36 of the crank 27 is eccentrically arranged on one side of the circular plate body 34 of the crank 27, and the rocker 36 of the crank 27 is hinged to the corresponding pitch sleeve 30, the pitch sleeve 30 can drive the corresponding crank to move up and down. The circular plate body 34 of the handle 27 rotates, thereby driving the corresponding blade 1 to rotate, so that the collective pitch angle of the blade 1 can be adjusted. The maximum operating speed of the present invention can reach 5000rpm, and the influence of icing of the blade 1 on the lift and torque under different rotor speeds and collective pitch angles can be measured. The variable collective pitch angle structure built into the rotor hub can greatly reduce the size of the rotor hub and effectively increase the test length of the blade extension direction of the test device. The variable collective pitch mechanism is built into the main shaft and the hub. When the test device is conducting an icing test, the built-in variable collective pitch mechanism is isolated from the airflow, so there will be no icing, which can avoid the variable collective pitch mechanism from getting stuck or causing dynamic balance problems that affect the test results, thereby greatly improving the operating reliability.

[0084] The above embodiments are merely exemplary descriptions of the present invention and do not limit its protection scope. Those skilled in the art may also make partial changes thereto, which are within the protection scope of the present invention as long as they do not exceed the spirit of the present invention.

Claims

1. An icing wind tunnel variable collective pitch angle rotor test device, characterized in that: It comprises a plurality of blades (1), a rotor main shaft (4), a six-component balance (9), a base (10), a rotor motor (12), a pitch-changing push rod (13), a bearing seat (15), a torque sensor (18), a crank (27) and a pitch-changing sleeve (30); The bearing seat (15), the six-component balance (9) and the base (10) are connected in sequence from top to bottom; the lower part of the rotor main shaft (4) is rotationally matched with the bearing seat (15); the pitch-changing push rod (13) is axially slidably matched with the upper part of the rotor main shaft (4); and the pitch-changing push rod (13) is circumferentially limitedly matched with the upper part of the rotor main shaft (4); the lower end of the rotor main shaft (4) passes through the six-component balance (9) and is connected to one end of the torque sensor (18); the other end of the torque sensor (18) is connected to the output shaft of the rotor motor (12) through the commutator (11); a lifting mechanism is provided on the bearing seat (15); the output end of the lifting mechanism is connected to the pitch-changing push rod (13); A propeller hub is arranged at the top end of a rotor main shaft (4), a pitch-changing cavity is arranged in the propeller hub, a plurality of connection holes are arranged on a circumferential wall of the propeller hub, the roots of a plurality of blades (1) are rotatably matched with the plurality of connection holes in a one-to-one correspondence, a square plug hole (33) is arranged on the root end surface of the blade (1), a pitch-changing box is sleeved on the top end of a pitch-changing push rod (13), the pitch-changing box is located in the pitch-changing cavity, a plurality of slide grooves (32) are arranged on the outer circumference of the pitch-changing box, and a pitch-changing sliding sleeve (33) is slidably arranged in the slide groove (32) 30), the crank (27) comprises a circular plate body (34) in the middle, a square protrusion (35) is provided on one end surface of the circular plate body (34), a rocker (36) is eccentrically provided on the other end surface of the circular plate body (34), the square protrusions (35) of the plurality of cranks (27) are plugged into and matched with the square sockets (33) of the plurality of blades (1) in a one-to-one correspondence, the rockers (36) of the plurality of cranks (27) are hingedly connected with the plurality of pitch-changing sleeves (30) in a one-to-one correspondence, and the slide groove (32) is perpendicular to the corresponding blade (1).

2. The icing wind tunnel variable collective pitch angle rotor test device according to claim 1, characterized in that: The lower part of the rotor main shaft (4) is rotatably matched with the bearing seat (15) via two main shaft bearings (24).

3. The icing wind tunnel variable collective pitch angle rotor test device according to claim 1, characterized in that: The pitch change box comprises a pitch change box upper plate (29) and a pitch change box lower plate (31) connected to each other in an upper and lower direction. A plurality of slide grooves (32) are formed on the outer periphery of the pitch change box lower plate (31), and the slide grooves (32) penetrate upwardly through the pitch change box lower plate (31). The pitch change box upper plate (29) blocks the upper openings of the plurality of slide grooves (32). A double-sided milling flat section (37) is provided at the top end of the pitch change push rod (13). The pitch change box upper plate (29) and the pitch change box lower plate (31) are sleeved on the double-sided milling flat section (37). A clamping ring (28) is connected to the top end of the pitch change push rod (13). The clamping ring (28) presses the pitch change box upper plate (29) and the pitch change box lower plate (31) onto the shaft shoulder at the bottom of the double-sided milling flat section (37).

4. The icing wind tunnel variable collective pitch angle rotor test device according to claim 1, characterized in that: The propeller hub is composed of a propeller hub upper plate (2) and a propeller hub lower plate (3) connected up and down.

5. The icing wind tunnel variable collective pitch angle rotor test device according to claim 1, characterized in that: A rotation speed encoder (16) is provided on the base (10), and a measuring swivel of the rotation speed encoder (16) is connected to the rotor main shaft (4).

6. An icing wind tunnel variable collective pitch angle rotor test device according to any one of claims 1 to 5, characterized in that: An inner hole is provided at the upper portion of the rotor main shaft (4), and the pitch-changing push rod (13) is slidably arranged in the inner hole of the rotor main shaft (4).

7. The icing wind tunnel variable collective pitch angle rotor test device according to claim 6, characterized in that: The lifting mechanism comprises a plurality of electric cylinders (14), a static ring pressure cover (6), a static ring (7), a dynamic ring (21), a dynamic ring pressure cover (19) and a total pitch adjustment bearing (20). Two transparent oblong holes are provided on the side wall of the inner hole of the rotor main shaft (4). The oblong holes are opened vertically. A push rod pin (22) is provided at the bottom of the pitch change push rod (13). The static ring pressure cover (6) and the static ring (7) are clamped on both sides of the outer ring of the total pitch adjustment bearing (20). The dynamic ring (21) and the dynamic ring pressure cover (19) The movable ring (21) is sleeved on the rotor main shaft (4), and the two ends of the push rod pin (22) pass through the two oblong holes respectively and are connected to the movable ring (21). The push rod pin (22) is slidably matched with the two oblong holes. The rear cylinder cover of the electric cylinder (14) is connected to the bearing seat (15). The outer periphery of the static ring (7) is evenly provided with a plurality of connecting ears, and the piston rods of the plurality of electric cylinders (14) are connected to the plurality of connecting ears one by one.

8. The icing wind tunnel variable collective pitch angle rotor test device according to claim 7, characterized in that: Two guide keys (5) are arranged on the outer circumference of the rotor main shaft (4), and two key slots are vertically arranged on the inner circumference of the moving ring (21). The two guide keys (5) are slidably matched with the two key slots.

9. The icing wind tunnel variable collective pitch angle rotor test device according to claim 7, characterized in that: The bearing seat (15) and the stationary ring (7) are connected via an anti-torsion arm (8).

10. The icing wind tunnel variable collective pitch angle rotor test device according to claim 7, characterized in that: The electric cylinder (14) is selected according to the thrust. The thrust F of the electric cylinder (14) is calculated by the following formula: ； Where: A is the safety factor; c is the effective distance between the lift action point of the blade (1) and the root axis of the blade (1), in meters; S is the effective distance between the rocker (36) and the root axis of the blade (1), in meters; μ is the friction coefficient when the pitch push rod (13) moves up and down to adjust the total pitch angle of the blade (1); n is the number of electric cylinders (14); T max is the maximum value of the rotor lift of the plurality of blades (1), in N; In the hovering state, the rotor lift T of the plurality of blades (1) is calculated as follows: ； is the blade tip loss coefficient; is the number of blades (1); is the rotation radius of the blade (1), in m; 0.7 of the blade (1) The lift coefficient of the airfoil at ; is the air density, in kg / m 3 ; is the chord length of the blade (1), in m; is the rotor speed of blade (1), in rad / s; When the maximum lift coefficient is reached, the total angle condition with the maximum lift coefficient can be obtained. The maximum value of T max .

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