Multi-degree-of-freedom pre-tightening force / interface rigidity in-situ measurement method and equipment

Abstract

The invention discloses a multi-degree-of-freedom pre-tightening force / interface rigidity in-situ measurement method and equipment, and belongs to the field of aerospace and the technical field of mechanical design and manufacturing. The device comprises six modules including Z, R, X and Y degree-of-freedom motion units, a pre-tightening force / interface rigidity measurement unit and a distance measurement unit, all the modules are connected layer by layer up and down, XYZR four-degree-of-freedom motion is realized, the pre-tightening force / interface rigidity measurement unit is used for measuring the pre-tightening force / interface rigidity of a bolt structure, the distance measurement unit is used for measuring the distance between the device and a measured rotor, and the distance measurement unit is used for measuring the distance between the device and the measured rotor. And a foundation is provided for centering work. According to the invention, the bolt pretightening force and the interface rigidity can be measured in the narrow space of the inner cavity of the aero-engine rotor, the XYZR four-degree-of-freedom platform is driven to move after the position of the bolt is identified through the depth camera and the position information is fed back, so that the tail end pretightening force / interface rigidity measuring unit can stretch / unfold to enter the rotor in an obstacle avoidance manner, and the measurement accuracy is improved. And the bolts on the measuring disc surface are rotated for one circle, so that the measuring efficiency is greatly improved.

Description

Technical Field

[0001] The present invention belongs to the field of measuring the connection state of aero-engines, and specifically relates to a method and equipment for in-situ measurement of pre-tightening force / interface stiffness with multiple degrees of freedom. Background Art

[0002] As the core component of an aero-engine, the rotor of an aero-engine uses a large number of bolt-step connection structures. The bolt pre-tightening force and interface stiffness are important factors to ensure the stability and reliability of the rotor. During the operation of the rotor, the pre-tightening force and interface stiffness will change with the change of load and working conditions, and the rotor system will generate additional unbalance, causing the vibration problem of the whole machine, and then affecting the service performance of the aero-engine. Therefore, it is of great significance to measure the bolt pre-tightening force and interface stiffness of the inner cavity part of the aero-engine rotor.

[0003] In the detection of bolt pre-tightening force and interface stiffness, compared with other measurement methods, the ultrasonic measurement technology has the advantages of not being restricted by material properties, strong in-situ measurement ability, and high sensitivity to interface measurement, meeting the basic conditions for in-situ measurement of aero-engine rotors.

[0004] At present, the existing detection devices for rotor bolt pre-tightening force / interface stiffness have the following problems:

[0005] (1) Poor accessibility. Due to the small diameter at the rotor inlet, it is difficult for the detection equipment to enter, and the inner cavity of the rotor is narrow with limited operating space, making it difficult for the existing devices to carry out relevant detection work therein.

[0006] (2) Low efficiency. Traditional detection work requires manual adjustment of the detection device, and it is difficult to achieve high-efficiency measurement in the case of a large number of bolts.

[0007] (3) Poor coordination. Due to the narrow inner cavity of the rotor, single-degree-of-freedom control is difficult to ensure the obstacle avoidance function of the device. Summary of the Invention

[0008] The purpose of the present invention is to solve the problem of difficult detection of bolt pre-tightening force / interface stiffness of aero-engines, and provide a multi-degree-of-freedom pre-tightening force / interface stiffness in-situ measurement equipment for it. The present invention can carry out the detection of pre-tightening force and interface stiffness in the narrow space of the aero-engine rotor. The XYZR four-degree-of-freedom motion platform can be used to achieve centering of the axis and repeated detection, and the ultrasonic detection actuator at the end realizes the in-situ measurement of bolt pre-tightening force / interface stiffness.

[0009] The technical solution of the present invention is as follows:

[0010] An in-situ measurement equipment for pre-tightening force / interface stiffness with multiple degrees of freedom, comprising: a Z-degree-of-freedom motion unit 1, an R-degree-of-freedom motion unit 4, a Y-degree-of-freedom motion unit 12, an X-degree-of-freedom motion unit 7, a pre-tightening force / interface stiffness measurement unit 11, and a distance measurement unit 9; the Z-degree-of-freedom motion unit 1 is used to realize the upward and downward movement of the base in the Z direction; the R-degree-of-freedom motion unit 4 is used to drive the whole Z-degree-of-freedom motion unit 1 to realize rotational motion; the X-degree-of-freedom motion unit 7 and the Y-degree-of-freedom motion unit 12 are used to drive the distance measurement unit 9 to adjust the pose in the X and Y directions; the pre-tightening force / interface stiffness measurement unit 11 is used to measure the pre-tightening force / interface stiffness of the surface to be measured; the distance measurement unit 9 is used to measure the distance from the surrounding rotors to be measured.

[0011] Further, the structure of the Z-degree-of-freedom motion unit 1 is as follows: the left Z-direction guide rail bottom plate 1-1 and the right Z-direction guide rail bottom plate are connected as a whole through the connecting plate A1-6, and the lowermost connecting plate A1-6 is fixed on the upper seat 1-9 through the upper seat connecting block 1-8. The Z-axis servo motor 1-13 connected with the servo motor reducer head 1-14 is fixed on the servo motor seat, and the servo motor seat is fixedly connected with the right Z-direction guide rail bottom plate. The pulley B1-17 on the Z-axis servo motor shaft is connected with the pulley A1-2 on the ball screw shaft through the belt A1-18. The ball screw head seat 1-15 and the ball screw tail seat 1-10 are both fixed inside the right Z-direction guide rail bottom plate for setting the ball screw A1-11. The ball screw A1-11 is connected to the nut seat 1-12. The bottom surface of the nut seat 1-12 is provided with a threaded hole and is connected to the base 1-7 through a nut, thereby converting the rotational motion of the ball screw A1-11 into the reciprocating motion of the base 1-7 along the Z direction. Linear guide rails A1-3 are respectively arranged on the inner sides of the left Z-direction guide rail bottom plate 1-1 and the right Z-direction guide rail bottom plate. The left and right Z-direction linear guide rails A1-3 are of a symmetric structure, and two sliders A1-4 are installed on both sides of the linear guide rails A1-3. The four sliders A1-4 are fixedly connected with the base 1-7, and the linear guide rails A1-3 play a role in Z-direction support and guidance. When the Z-axis servo motor 1-13 operates, through the belt A1-18, the pulley B1-17 and the pulley A1-2, it drives the ball screw A1-11 to rotate. Since the nut seat 1-12 cannot rotate, it realizes the movement along the direction of the ball screw A1-11, that is, the Z direction, and further drives the base 1-7 to realize upward and downward movement.

[0012] The Z-axis positive limiter 2 and the Z-axis negative limiter 3 are respectively fixed at the top end and the bottom end of the left Z-direction guide rail bottom plate 1-1 to ensure the safety of the Z-direction movement of the base 1-7. The wire groove 15 is fixed on the top frame 4-5 for leading out the wires of the Z-axis servo motor control components.

[0013] Furthermore, the structure of the R-degree-of-freedom motion unit 4 is as follows: The upper seat 1-9 is fixedly connected to the inner ring 4-1 of the slewing bearing. The washer 4-2 is fixedly connected to the inner ring 4-1 of the slewing bearing. The inner ring 4-1 of the slewing bearing is rotatably connected to the outer ring 4-3 of the slewing bearing. The outer ring 4-3 of the slewing bearing is fixedly connected to the lower connecting plate 4-4 of the gear. The lower connecting plate 4-4 of the gear is fixedly connected to the top frame 4-5. The R-axis servo motor 4-6 is connected to the upper seat 1-9 through the servo motor base 4-7. A pinion is installed on the R-axis servo motor shaft. The pinion meshes with the outer ring 4-3 of the slewing bearing and can drive the entire Z-degree-of-freedom motion unit 1 to achieve rotational motion.

[0014] The R-axis limiter 14 is fixed at the lower right corner of the top frame 4-5.

[0015] Furthermore, the structure of the X-degree-of-freedom motion unit 7 is as follows: The left and right X-direction linear guide rails B7-2 are symmetric in structure. The linear guide rails B7-2 are fixed on the middle layer frame 7-1. Two sliders B7-3 are installed on each of the linear guide rails B7-2. The sliders B7-3 are fixedly connected to the top frame 4-5. The linear guide rails B7-2 play a role in supporting and guiding the X-direction motion. The X-axis servo motor 7-9 is fixed on the middle layer frame 7-1 through the motor base A7-10. The X-axis servo motor 7-9 and the ball screw B7-13 are connected by a coupling A7-11. The ball screw slide A7-14 passes through the ball screw B7-13 and is fixedly connected to the top frame 4-5. The pulley is fixedly connected to the end of the ball screw B7-13 by a key connection. The driven pulley A7-4 at the end of the driven ball screw A7-7 is connected in the same way. The belt B7-16 connects the pulleys at the ends of the ball screw B7-13 and the driven ball screw A7-7 and the driven pulley A7-4 respectively. The driven screw slide 7-6 passes through the driven ball screw A7-7 and is fixedly connected to the top frame 4-5. The ball screw B7-13 and the driven ball screw A7-7 are located on both sides of the outer ring 4-3 of the slewing bearing. The left and right X-direction linear guide rails B7-2 are respectively located on both sides of the driven ball screw A7-7 and the ball screw B7-13. When the X-axis servo motor 7-9 operates, it drives the ball screw B7-13 to rotate through the coupling A7-11. Since the ball screw slide A7-14 cannot rotate, it realizes the movement along the direction of the ball screw B7-13, that is, the X-direction movement, and then drives the top frame 4-5 to move in the X-direction. In addition, the driven screw slide 7-6 is driven to move through the pulley and the belt B7-16, synchronously driving the top frame 4-5 to move, making its movement smoother.

[0016] The X-axis forward limiter 5 and the X-axis reverse limiter 6 are respectively fixed at the front and rear ends on the left side of the middle layer frame 7-1 to ensure the safety of the X-direction movement.

[0017] The structure of the Y-degree-of-freedom motion unit 12 is as follows: The linear guide rails C12-7 in the front and rear Y-directions are symmetrically structured. The linear guide rails C12-7 are fixed on the chassis 12-8. Two sliders C12-6 are installed on each of the linear guide rails C12-7. The sliders C12-6 are fixedly connected to the middle layer frame 7-1. The linear guide rails C12-7 play a role in supporting and guiding the Y-direction motion; The Y-axis servo motor 12-16 is fixed on the chassis 12-8 through the motor base B12-17. The Y-axis servo motor 12-16 and the ball screw C12-13 are connected through the coupling B12-15. The ball screw slide B12-12 passes through the ball screw C12-13 and is fixedly connected to the middle layer frame 7-1. The pulley C12-10 is fixedly connected to the end of the ball screw C12-13 by key connection. The connection method of the driven pulley B12-5 at the end of the driven ball screw B12-2 is the same; The belt C12-9 is respectively connected to the pulley C12-10 at the end of the ball screw C12-13 and the driven pulley B12-5 at the end of the driven ball screw B12-2. The driven ball screw slide 12-3 passes through the driven ball screw B12-2 and is fixedly connected to the middle layer frame 7-1. When the Y-axis servo motor 12-16 operates, it drives the ball screw C12-13 to rotate through the coupling. Since the ball screw slide B12-12 cannot rotate, it realizes the movement along the rotation direction of the ball screw C12-13, that is, the Y-direction movement, and further drives the middle layer frame 7-1 to move in the Y-direction. In addition, the driven ball screw slide 12-3 is driven to move through the pulley C12-10 and the belt C12-9, and the middle layer frame 7-1 is synchronously driven to move, making its movement smoother.

[0018] The Y-axis positive limit stop 13 and the Y-axis negative limit stop 8 are respectively fixed at the left and right ends of the rear side of the chassis 12-8 to ensure the safety of the normal Y-direction movement.

[0019] Furthermore, the structure of the pre-tightening force / interface stiffness measurement unit 11 is as follows: The adapter plate 11-1 is used for fixedly connecting with the base body 1-7; the adapter plate 11-1 is fixedly connected to the top end of the column 11-4; the camera mount 11-2 is fixed to the upper end of the column 11-4 and is used for fixing the depth camera 11-3; the upper electromagnet seat, the slide table, the upper servo motor seat 11-18, the lower electromagnet seat 11-10, and the lower servo motor seat are all fixed on the column 11-4; a through hole is opened at the end of the upper servo motor seat 11-18 for connecting the upper servo motor 11-17; the upper servo motor shaft is connected to the upper servo motor disk through a spline, the upper servo motor disk is fixedly connected to the upper servo motor rotating plate 11-16, the end of the upper servo motor rotating plate 11-16 is connected to the upper probe connecting rod fixing block 11-15, and a square through hole is opened in the upper probe connecting rod fixing block 11-15 for connecting the upper probe connecting rod 11-14. The end of the upper probe connecting rod 11-14 is fixedly connected to the upper probe housing 11-13. Inside the upper probe housing 11-13, there are an upper pressure sensor and an upper probe 11-12 from top to bottom; an upper electromagnet is arranged at the end of the upper electromagnet seat for powering on the upper servo motor 11-17; the servo motor 11-8 is connected to the slide table through the motor adapter 11-7, and the servo motor shaft is connected to the ball screw D 11-5 through a coupling; the slide table slider 11-6 passes through the ball screw D 11-5. One side of the slide table slider 11-6 is slidably connected to the slide table, and the other side of the slide table slider 11-6 is connected to one side of the slide table adapter plate 11-9; the other side of the slide table adapter plate 11-9 is connected to the lower electromagnet seat 11-10 and the lower servo motor seat; a lower electromagnet 11-11 is arranged at the end of the lower electromagnet seat 11-10 for powering on the lower servo motor; a through hole is opened at the end of the lower servo motor seat for connecting the lower servo motor; the lower servo motor shaft is connected to the lower servo motor disk through a spline, the lower servo motor disk is fixedly connected to the lower servo motor rotating plate, the end of the lower servo motor rotating plate is connected to the lower probe connecting rod fixing block, and a square through hole is opened in the lower probe connecting rod fixing block for connecting the lower probe connecting rod. The end of the lower probe connecting rod is connected to the lower probe housing through a screw. Inside the lower probe housing, there are a lower pressure sensor and a probe from bottom to top.

[0020] Further, the structure of the distance measuring unit 9 is as follows: The distance measuring unit 9 is fixed on the inner ring 4-1 of the slewing bearing by a clamping plate. The clamping plate is connected to the upper end of the upper support rod 9-12. The upper support rod 9-12 is located at the center of the inner ring 4-1 of the slewing bearing. The lower end of the upper support rod 9-12 is connected to the adapter block C9-10. The adapter block C9-10 is fixedly connected to the connecting seat 9-11. The limit block 9-9 is fixedly connected to the adapter block C9-10. The connecting seat 9-11 is horizontally arranged and internally embedded with a linear guide rail D9-8. The limit block 9-9 is located at the outer end of the linear guide rail D9-8. The other outer end of the linear guide rail D9-8 is provided with an adapter block A9-1 through a slider connecting plate 9-2. The adapter block A9-1 can slide along the guide rail. The lower support rod 9-3 is fixedly arranged below the adapter block A9-1. The connecting plate B9-4 is fixedly arranged below the lower support rod 9-3. The connecting plate B9-4 is connected to the adapter block B9-5. The infrared distance measuring sensor 9-6 is connected to the adapter block B9-5 through a sensor seat 9-7. The distance between the distance measuring sensor 9-6 and the rotor can be adjusted, which is convenient for measurement. The limit block 9-9 functions to limit the movement of the adapter block 9-1.

[0021] Furthermore, the ball screw headstock fixing bracket 1-5 is used to fix the ball screw headstock 1-15 inside the Z-direction right guide rail bottom plate; the servo motor reducer headstock 1-16 is used to fix the servo motor reducer head 1-14 outside the Z-direction right guide rail bottom plate.

[0022] Furthermore, the ball screw fixed headstock A7-12 and the ball screw fixed tailstock A7-15 are fixed on the middle layer frame 7-1 to support the ball screw B7-13; the driven ball screw fixed headstock A7-5 and the driven ball screw fixed tailstock A7-8 are fixed on the middle layer frame 7-1 to support the driven ball screw A7-7.

[0023] Furthermore, the driven ball screw fixed tailstock B12-1 and the driven ball screw fixed headstock B12-4 are fixed on the chassis 12-8 to support the driven ball screw B12-2; the upper ball screw fixed tailstock B12-11 and the ball screw fixed headstock B12-14 are fixed on the chassis 12-8 to support the ball screw C12-13.

[0024] The beneficial effects of the present invention:

[0025] (1) Good accessibility. The end preload / interface stiffness measurement unit is designed as a retractable structure and enters the rotor in a retracted state and then presents an unfolded state to start the measurement work.

[0026] (2) High efficiency. After the bolt position is identified by the depth camera and the position information is fed back, the XYZR four-degree-of-freedom platform is driven to move, so that the end preload / interface stiffness measurement unit automatically rotates to measure the bolts on the measurement disk surface for one week, greatly improving the measurement efficiency.

[0027] (3) Good coordination. When the pre-tightening force / interface stiffness measurement unit enters, measures, and exits the rotor, the device avoids obstacles through multi-degree-of-freedom control. Description of the Drawings

[0028] Figure 1 It is a schematic structural diagram of the whole invention;

[0029] Figure 2 It is a schematic structural diagram of the Z-degree-of-freedom motion unit in the invention after hiding a connecting plate;

[0030] Figure 3 It is a schematic structural diagram of the R-degree-of-freedom motion unit in the invention;

[0031] Figure 4 It is a schematic structural diagram of the X-degree-of-freedom motion unit in the invention;

[0032] Figure 5 It is a schematic structural diagram of the Y-degree-of-freedom motion unit in the invention;

[0033] Figure 6 It is a schematic structural diagram of the pre-tightening force / interface stiffness measurement unit in the invention;

[0034] Figure 7 It is a schematic structural diagram of the distance measurement unit in the invention;

[0035] Figure 8 It is a cross-sectional view of the structure of the real rotor part;

[0036] Figure 9 It is a schematic diagram of the working state in the rotor inner cavity when the invention measures the bolt pre-tightening force / interface stiffness;

[0037] The markings of each component in the attached drawings are as follows: 1. Z-degree-of-freedom motion unit; 2. Z-axis forward limiter; 3. Z-axis reverse limiter; 4. R-degree-of-freedom motion unit; 5. X-axis forward limiter; 6. X-axis reverse limiter; 7. X-degree-of-freedom motion unit; 8. Y-axis reverse limiter; 9. ranging unit; 10. footrest; 11. pre-tightening force / interface stiffness measurement unit; 12. Y-degree-of-freedom motion unit; 13. Y-axis forward limiter; 14. R-axis limiter; 15. wire groove; 1-1. Z-direction left guide base plate; 1-2. pulley A; 1-3. linear guide A; 1-4. slider A; 1-5. ball screw head fixing bracket; 1-6. connecting plate A; 1-7. base body; 1-8. upper seat connecting block; 1-9. upper seat; 1-10. ball screw tail seat; 1-11. ball screw A; 1-12. nut seat; 1-13. Z-axis servo motor; 1-14. servo motor reduction head; 1-15. ball screw head; 1-16. servo motor reduction head seat; 1-17. pulley B; 1-18. belt A; 4-1. inner ring of slewing bearing; 4-2. washer; 4-3. outer ring of slewing bearing; 4-4. lower connecting plate of gear; 4-5. top frame; 4-6. R-axis servo motor; 4-7. servo motor seat; 7-1. middle layer frame; 7-2. linear guide B; 7-3. slider B; 7-4. driven pulley A; 7-5. fixed head of driven ball screw A; 7-6. driven screw slide; 7-7. driven ball screw A; 7-8. fixed tail of driven ball screw A; 7-9. X-axis servo motor; 7-10. motor seat A; 7-11. coupling A; 7-12. fixed head of ball screw A; 7-13. ball screw B; 7-14. ball screw slide A; 7-15. fixed tail of ball screw A; 7-16. belt B; 12-1. fixed tail of driven ball screw B; 12-2. driven ball screw B; 12-3. driven ball screw slide; 12-4. fixed head of driven ball screw B; 12-5. driven pulley B; 12-6. slider C; 12-7. linear guide C; 12-8. bottom frame; 12-9. belt C; 12-10. pulley C; 12-11. fixed tail of ball screw B; 12-12. ball screw slide B; 12-13. ball screw C; 12-14. fixed head of ball screw B; 12-15. coupling B; 12-16. Y-axis servo motor; 12-17. motor seat B; 11-1. adapter plate; 11-2. camera seat; 11-3. depth camera; 11-4. column; 11-5. ball screw D; 11-6. slide block of slide; 11-7. motor adapter seat; 11-8. servo motor; 11-9. slide adapter plate; 11-10. lower electromagnet seat; 11-11. lower electromagnet; 11-12. upper probe; 11-13. upper probe housing; 11-14. upper probe connecting rod; 11-15. fixed block of upper probe connecting rod; 11-16. upper servo motor rotating plate;11-17. Upper servo; 11-18. Upper servo base; 9-1. Adapter block A; 9-2. Slide block connecting plate; 9-3. Lower support rod; 9-4. Connecting plate B; 9-5. Adapter block B; 9-6. Infrared ranging sensor; 9-7. Sensor base; 9-8. Linear guide D; 9-9. Limit block; 9-10. Adapter block C; 9-11. Connecting seat; 9-12. Upper support rod Detailed implementation mode

[0038] The following further describes the detailed content and specific implementation mode of the present invention in conjunction with the drawings.

[0039] As Figures 1 to 7 shown, the equipment of the present invention can be mainly divided into six major modules: Z-degree-of-freedom motion unit 1, R-degree-of-freedom motion unit 4, X-degree-of-freedom motion unit 7, Y-degree-of-freedom motion unit 12, pre-tightening force / interface stiffness measurement unit 11, and ranging unit 9. The structural framework of the Z-degree-of-freedom motion unit 1 is: the Z-axis left guide rail bottom plate 1-1 is connected to the Z-axis right guide rail bottom plate through the connecting plate A1-6. The lowermost connecting plate A1-6 is fixed on the upper seat 1-9 through the upper seat connecting block 1-8. Linear guide rails A1-3 are connected to the inner sides of the guide rail bottom plates on both the left and right sides by bolts. The slide block A1-4 arranged on the linear guide rail A1-3 is connected to the base body 1-7 by bolts, providing support and guidance for the base body 1-7 to move along the Z-axis. The motion framework of the Z-degree-of-freedom motion unit 1 is: the output shaft of the Z-axis servo motor 1-13 connected with the servo motor reducer head 1-14 is connected to the pulley B1-17 by a key. The motion is transmitted to the pulley A1-2 through the belt A1-18. The pulley A1-2 is connected to the end of the ball screw A1-11 by a key, driving it to rotate. The ball screw head seat 1-15 and the ball screw tail seat 1-10 fix the ball screw and are connected to the Z-axis right guide rail bottom plate 1-1. The nut seat 1-12 on the ball screw is connected to the base body 1-7 by bolts, thereby converting the rotational motion of the screw into the reciprocating motion of the base body 1-7 along the Z-axis. In addition, the Z-axis forward limiter 2 and the Z-axis reverse limiter 3 fixed on the Z-axis left guide rail bottom plate 1-1 are used for Z-axis motion limiting. When the fixing screw on the base body 1-7 passes through the limiter, the Z-axis motion stops.

[0040] The upper seat 1-9 and the inner ring 4-1 of the slewing bearing are connected by bolts to realize the connection between the structural frame of the above-mentioned Z-degree-of-freedom motion unit 1 and the structural frame of the lower R-degree-of-freedom motion unit 4; the structural frame of the R-degree-of-freedom motion unit 4 is: the inner ring 4-1 of the slewing bearing and the outer ring 4-3 of the slewing bearing are rotationally connected through rolling elements and raceways, and the washer 4-2 in the middle plays a buffering and protective role. The lower side of the outer ring 4-3 of the slewing bearing is connected to the lower connecting plate 4-4 of the gear, and the lower connecting plate 4-4 of the gear is fixed on the top frame 4-5 by bolts; the motion frame of the R-degree-of-freedom motion unit 4 is: the output shaft of the R-axis servo motor 4-6 fixed on the inner ring 4-1 of the slewing bearing through the servo motor base 4-7 is connected to the pinion through a key, and the pinion meshes with the outer ring 4-3 of the slewing bearing. During motion, the acting force is transmitted to the outer ring 4-3 of the slewing bearing through the pinion, and the reaction force from the outer ring 4-3 of the slewing bearing drives the inner ring 4-1 of the slewing bearing connected to the upper seat 1-9 to rotate, thereby realizing the rotation of the Z-degree-of-freedom motion unit 1.

[0041] The above structure is connected to the slider B7-3, the driven lead screw slide 7-6, and the ball screw slide A7-14 through the top frame 4-5, realizing the connection between the upper R-degree-of-freedom motion unit 4 and the lower X-degree-of-freedom motion unit 7. Among them, the slider B7-3 carried by the linear guide B7-2 fixed on the middle layer frame 7-1 plays a supporting and guiding role; the driven lead screw slide 7-6 and the ball screw slide A7-14 are used to transmit the rotational motion of the ball screw B7-13 to the top frame 4-5 to realize the movement of the top frame 4-5 in the X direction. The coupling A7-10 transmits the rotational motion of the X-axis servo motor 7-9 to the ball screw B7-13, and the driven pulley A7-4, the pulley and the belt B7-16 transmit the motion of the ball screw B7-13 to the driven ball screw A7-7; in addition, the X-axis forward limiter 5 and the X-axis reverse limiter 6 fixed on the middle layer frame 7-1 are used for X-axis motion limiting. When the fixing screw on the top frame 4-5 passes through the limiter, the X-axis motion stops.

[0042] The above structure is connected to the slider C12-6, the driven ball screw slide 12-3, and the ball screw slide B12-12 through the middle layer frame 7-1, realizing the connection between the upper X-degree-of-freedom motion unit 7 and the lower Y-degree-of-freedom motion unit 12. Among them, the slider C12-6 carried by the linear guide C12-7 fixed on the base frame 12-8 plays a supporting and guiding role; the driven ball screw slide 12-3 and the ball screw slide B12-12 are used to transmit the rotational motion of the ball screw C12-13 to the middle layer frame 7-1 to realize the movement of the middle layer frame 7-1 in the Y direction. The coupling B12-15 transmits the rotational motion of the Y-axis servo motor 12-16 to the ball screw C12-13, and the driven pulley B12-5, the pulley C12-10, and the belt C12-9 transmit the motion of the ball screw C12-13 to the driven ball screw B12-2; in addition, the Y-axis forward limiter 13 and the Y-axis reverse limiter 8 fixed on the base frame 12-8 are used for Y-axis motion limiting. When the fixing screw on the base frame 12-8 passes through the limiter, the Y-axis motion stops.

[0043] The above overall structure can already realize the movement of the base 1-7 in four degrees of freedom of XYZR, and the limiters in each direction ensure the reliability of the movement range.

[0044] The pre-tightening force / interface stiffness measurement unit 11 is connected to the base 1-7 through the adapter plate 11-1 at the end. The depth camera 11-2 fixed on the column 11-4 through the camera mount 11-2 is used to identify the measured bolt and its position. The upper servo motor 11-17 is fixed on the column 11-4 through the upper servo motor mount 11-18. The electromagnet is used to supply power to the servo motor. The upper servo motor 11-17 can drive the upper servo motor rotating plate 11-16 to rotate through the rotating shaft, thereby realizing the position control of the upper probe 11-12. A pressure sensor is arranged inside the upper probe housing 11-13. When the probe contacts the measured part, the pressure will be transmitted to the pressure sensor through the probe; the structure of the lower probe is similar to that of the upper probe 11-12. However, it should be noted that the lower probe module is assembled on the ball screw module, and the rotation of the ball screw D11-5 is driven by the rotation of the servo motor 11-8 shaft, thereby moving the lower probe module connected to the slide block 11-6 up and down to adjust the distance between the lower probe and the surface of the measured part.

[0045] The distance measuring unit 9 is fixed on the inner ring 4-1 of the slewing bearing through a clamping plate. The clamping plate is connected to the upper end of the upper support rod 9-12. The upper support rod 9-12 is located at the center of the inner ring 4-1 of the slewing bearing. The lower end of the upper support rod 9-12 is connected to the adapter block C9-10. The adapter block C9-10 is fixedly connected to the connecting seat 9-11. The limiting block 9-9 is fixedly connected to the adapter block C9-10. The adapter block C9-10, the connecting seat 9-11, and the upper support rod 9-12 are used to extend and fix the distance measuring unit 9, so it can move in three degrees of freedom of X, Y, and R. The connecting seat 9-11 is horizontally arranged and internally embedded with a linear guide rail D9-8. The limiting block 9-9 is located at the outer end of the linear guide rail D9-8. The other outer end of the linear guide rail D9-8 is provided with an adapter block A9-1 through a slider connecting plate 9-2. The adapter block A9-1 can slide along the guide rail. The lower support rod 9-3 is fixedly arranged below the adapter block A9-1. The lower connecting plate B9-4 is fixedly arranged below the lower support rod 9-3. The connecting plate B9-4 is connected to the adapter block B9-5. The infrared distance measuring sensor 9-6 is connected to the adapter block B9-5 through a sensor seat 9-7. The distance between the distance measuring sensor 9-6 and the rotor can be adjusted, which is convenient for measurement. The limiting block 9-9 plays a role in limiting the movement of the adapter block 9-1.

[0046] The implementation steps of the present invention are as follows:

[0047] (1) Centering stage; Place the rotor to be measured in the area to be detected. The R-degree-of-freedom motion unit 4 moves, driving the distance measuring unit 9 to rotate one week in steps of 90°. Taking the initial state as 0°, measure the distance from the rotor to be measured at four positions of 0° (i.e., 360°), 90°, 180°, and 270° respectively. During the rotation process, the X-degree-of-freedom motion unit 7 and the Y-degree-of-freedom motion unit 12 move, driving the distance measuring unit 9 to adjust its pose in the X and Y directions, so that the readings of the infrared distance measuring sensor 9-6 at the above four positions are equal after finally rotating one week. At this time, the pre-tightening force / interface stiffness measuring unit 11 is coaxial with the rotor to be measured, and the measurement work can be started.

[0048] (2) Measurement preparation stage; The Z-degree-of-freedom motion unit 1 moves, driving the base 1-7 to move downward along the negative Z-axis, that is, the end pre-tightening force / interface stiffness measuring unit 11 moves downward. Before entering the inner cavity of the rotor, the upper and lower servos drive the upper and lower servo turntables to rotate, so that the upper and lower servo turntables are in a vertical state. The purpose of this is to avoid collision with the rotor to be measured during the descent process. When the lower probe passes through the inlet of the labyrinth disc, the lower servo drives the lower servo turntable to rotate counterclockwise, so that the lower probe surface is parallel to the surface to be measured. The upper servo 11-17 drives the upper servo turntable 11-16 to rotate clockwise, so that the upper probe 11-12 surface is parallel to the surface to be detected.

[0049] (3) Measurement in progress stage; The Z-degree-of-freedom motion unit 1 continues to move, driving the preload / interface stiffness measurement unit 11 to continue moving downward until the upper probe 11-12 contacts the workpiece to be measured, completing the measurement of the upper probe 11-12 on the surface to be measured; The servo motor 11-8 moves, driving the lower probe connected to the slide block 11-6 to move upward along the Z-axis until the lower probe contacts the surface to be measured, completing the measurement of the lower probe on the surface to be measured.

[0050] (4) Measurement end stage; After the measurement work is completed, the upper servo motor 11-17 drives the upper servo motor turntable 11-16 to rotate counterclockwise, making the upper servo motor turntable 11-16 in a vertical state; The lower servo motor drives the lower servo motor turntable to rotate clockwise by 30°, and the Z-degree-of-freedom motion unit 1 moves, driving the preload / interface stiffness measurement unit 11 to move upward. During the upward movement, the lower servo motor continues to drive the lower servo motor turntable to rotate clockwise. When passing through the labyrinth disk, ensure that the lower servo motor turntable is in a vertical state; The entire preload / interface stiffness measurement unit 11 is removed from the inner cavity of the rotor to be detected.

[0051] It should be noted that during the measurement process, due to the narrow inlet and inner cavity of the rotor and the need for the preload / interface stiffness measurement unit 11 at the end to expand and contract, the obstacle avoidance function is necessary. The present invention ensures the obstacle avoidance function of the device through multi-degree-of-freedom control. Specifically: When the preload / interface stiffness measurement unit 11 enters the cavity opening in a telescopic state, the direct expansion of the lower probe measurement structure will collide with the rear cone; and when the preload / interface stiffness measurement unit 11 finishes measuring the bolt and exits the rotor, the direct contraction of the lower probe measurement structure will also collide with the rear cone. The obstacle avoidance solution in the present invention is: During the process of the Z-degree-of-freedom motion unit 1 driving the preload / interface stiffness measurement unit 11 to descend, when the lower probe measurement structure passes through the labyrinth disk opening, drive the lower servo motor to control the lower servo motor turntable to rotate counterclockwise and expand in advance; Similarly, after the measurement is completed, drive the lower servo motor to control the lower servo motor turntable to rotate clockwise by 30°. At this time, the lower probe will not collide with the rear cone. Then control the Z-degree-of-freedom motion unit 1 to drive the preload / interface stiffness measurement unit 11 to rise. After rising a certain distance, continue to drive the lower servo motor to control the lower servo motor turntable to rotate clockwise until it reaches a vertical state and safely passes through the labyrinth disk opening; The above realizes the obstacle avoidance function through multi-degree-of-freedom motion control.

Claims

1. Multi-degree-of-freedom preload / interface stiffness in-situ measurement equipment, characterized by: include: The invention relates to a Z degree of freedom motion unit (1), an R degree of freedom motion unit (4), a Y degree of freedom motion unit (12), an X degree of freedom motion unit (7), a preload / interface stiffness measuring unit (11), and a distance measuring unit (9); the Z degree of freedom motion unit (1) is used to realize the ascending and descending motion of the base body in the Z direction; the R degree of freedom motion unit (4) is used to drive the Z degree of freedom motion unit (1) to realize the rotational motion as a whole; the X degree of freedom motion unit (7) and the Y degree of freedom motion unit (12) are used to drive the distance measuring unit (9) to adjust the position in the X and Y directions; the preload / interface stiffness measuring unit (11) is used to measure the preload / interface stiffness of the surface to be measured; and the distance measuring unit (9) is used to measure the distance to the surrounding rotor to be measured.

2. The multi-degree-of-freedom preload / interface stiffness in-situ measurement equipment according to claim 1, characterized in that: The structure of the Z-degree-of-freedom motion unit (1) is as follows: a Z-direction left guide rail base plate (1-1) and a Z-direction right guide rail base plate are connected as a whole through a connecting plate A (1-6), and the lowest connecting plate A (1-6) is fixed to an upper seat (1-9) through an upper seat connecting block (1-8); a Z-axis servo motor (1-13) connected to a servo motor reduction head (1-14) is fixed to a servo motor seat, and the servo motor seat is fixedly connected to the Z-direction right guide rail base plate, and the Z-axis servo motor (1-13) is fixed to a servo motor seat. The pulley B (1-17) on the servo motor shaft is connected to the pulley A (1-2) on the ball screw shaft through the belt A (1-18). The ball screw head seat (1-15) and the ball screw tail seat (1-10) are fixed inside the Z-direction right guide rail base plate for setting the ball screw A (1-11). The ball screw A (1-11) is connected to the nut seat (1-12). The bottom surface of the nut seat (1-12) is provided with a threaded hole. The nut and the base are connected by the nut. The base (1-7) is connected to the left side of the Z-direction guide rail base plate (1-1) and the right side of the Z-direction guide rail base plate, thereby converting the rotational motion of the ball screw A (1-11) into a reciprocating motion of the base (1-7) along the Z direction; a linear guide rail A (1-3) is respectively arranged on the inner side of the left Z-direction guide rail base plate (1-1) and the right Z-direction guide rail base plate; the left and right Z-direction linear guide rails A (1-3) are symmetrical structures; two sliders A (1-4) are arranged on the linear guide rails A (1-3) on both sides; the four sliders A (1-4) are connected to the base (1-7) and the base (1-7) along the Z direction. 7) is fixedly connected, and the linear guide rail A (1-3) plays a role of Z-direction support and guidance; when the Z-axis servo motor (1-13) is running, the ball screw A (1-11) is driven to rotate through the belt A (1-18), the pulley B (1-17) and the pulley A (1-2). Since the nut seat (1-12) cannot rotate, it is realized along the direction of the ball screw A (1-11), that is, the Z-direction movement, thereby driving the base (1-7) to achieve rising and falling; The Z-axis positive limiter (2) and the Z-axis reverse limiter (3) are respectively fixed on the top and bottom of the Z-axis left guide rail bottom plate (1-1) to ensure the safety of the Z-axis movement of the base (1-7); the wire trough (15) is fixed on the top frame (4-5) to lead out the wires of the Z-axis servo motor control element.

3. The multi-degree-of-freedom preload / interface stiffness in-situ measurement equipment according to claim 1, characterized in that: The structure of the R degree of freedom motion unit (4) is as follows: the upper seat (1-9) and the slewing bearing inner ring (4-1) are fixedly connected, the washer (4-2) and the slewing bearing inner ring (4-1) are fixedly connected, the slewing bearing inner ring (4-1) and the slewing bearing outer ring (4-3) are rotatably connected, the slewing bearing outer ring (4-3) and the gear lower connecting plate (4-4) are fixedly connected, and the gear lower connecting plate (4-4) and the top frame (4-5) are fixedly connected; the R axis servo motor (4-6) is connected to the upper seat (1-9) through the servo motor seat (4-7), and a small gear is installed on the R axis servo motor shaft, and the small gear is meshed with the slewing bearing outer ring (4-3), which can drive the Z degree of freedom motion unit (1) to realize rotational motion as a whole; The R-axis limiter (14) is fixed at the lower right corner of the top frame (4-5).

4. The multi-degree-of-freedom preload / interface stiffness in-situ measurement equipment according to claim 1, characterized in that: The structure of the X-degree-of-freedom motion unit (7) is as follows: the left and right X-direction linear guide rails B (7-2) are symmetrical in structure, the linear guide rails B (7-2) are fixed on the middle frame (7-1), two sliders B (7-3) are installed on the linear guide rails B (7-2), the sliders B (7-3) are fixedly connected to the top frame (4-5), and the linear guide rails B (7-2) play a supporting and guiding role for X-direction motion; the X-axis servo motor (7-9) is fixed to the middle frame (7-10) through the motor seat A (7-10). -1), the X-axis servo motor (7-9) and the ball screw B (7-13) are connected by a coupling A (7-11), the ball screw slide A (7-14) passes through the ball screw B (7-13) and is fixedly connected to the top frame (4-5), the pulley is fixed to the end of the ball screw B (7-13) by a key connection, and the driven pulley A (7-4) at the end of the driven ball screw A (7-7) is connected in the same way; the belt B (7-16) is connected to the ball screw B (7- The driven ball screw slide (7-6) passes through the driven ball screw A (7-7) and is fixedly connected to the top frame (4-5); the ball screw B (7-13) and the driven ball screw A (7-7) are located on both sides of the slewing bearing outer ring (4-3); the left and right X-direction linear guides B (7-2) are respectively located on both sides of the driven ball screw A (7-7) and the ball screw B (7-13). side; when the X-axis servo motor (7-9) is running, the ball screw B (7-13) is driven to rotate through the coupling A (7-11). Since the ball screw slide A (7-14) cannot rotate, it moves along the direction of the ball screw B (7-13), that is, in the X direction, and then drives the top frame (4-5) to move along the X direction; in addition, the driven screw slide (7-6) is driven to move through the pulley and the belt B (7-16), and the top frame (4-5) is driven to move synchronously, so that its movement is more stable; The X-axis positive limiter (5) and the X-axis reverse limiter (6) are respectively fixed to the front and rear ends of the left side of the middle frame (7-1) to ensure the safety of X-axis movement; The structure of the Y-degree-of-freedom motion unit (12) is as follows: the Y-direction linear guide rails C (12-7) on the front and rear sides are symmetrical in structure, the linear guide rails C (12-7) are fixed on the base frame (12-8), two sliders C (12-6) are installed on the linear guide rails C (12-7), the sliders C (12-6) are fixedly connected to the middle frame (7-1), and the linear guide rails C (12-7) play a supporting and guiding role for Y-direction motion; the Y-axis servo motor (12-16) is driven by the Y-axis servo motor (12-16) The motor seat B (12-17) is fixed on the base frame (12-8), the Y-axis servo motor (12-16) and the ball screw C (12-13) are connected through the coupling B (12-15), the ball screw slide B (12-12) passes through the ball screw C (12-13) and is fixedly connected to the middle frame (7-1), the pulley C (12-10) is fixed to the end of the ball screw C (12-13) through a key connection, and the driven ball screw B (12- 2) The driven pulley B (12-5) at the end is connected in the same way; the belt C (12-9) is connected to the pulley C (12-10) and the driven pulley B (12-5) at the end of the ball screw C (12-13) and the end of the driven ball screw B (12-2) respectively, and the driven ball screw slide (12-3) passes through the driven ball screw B (12-2) and is fixedly connected to the middle frame (7-1); when the Y-axis servo motor (12-16) is running, The ball screw C (12-13) is driven to rotate by the coupling. Since the ball screw slide B (12-12) cannot rotate, it moves along the rotation direction of the ball screw C (12-13), that is, the Y direction, thereby driving the middle frame (7-1) to move along the Y direction; in addition, the driven ball screw slide (12-3) is driven to move by the pulley C (12-10) and the belt C (12-9), and the middle frame (7-1) is driven to move synchronously, so that its movement is more stable; The Y-axis positive limiter (13) and the Y-axis reverse limiter (8) are respectively fixed to the left and right ends of the rear side of the base frame (12-8) to ensure the safety of normal movement in the Y direction.

5. The multi-degree-of-freedom preload / interface stiffness in-situ measurement equipment according to claim 1, characterized in that: The structure of the preload force / interface stiffness measuring unit (11) is as follows: the adapter plate (11-1) is used for fixed connection with the base (1-7); the adapter plate (11-1) is fixedly connected to the top of the column (11-4); the camera seat (11-2) is fixed to the upper end of the column (11-4) and is used to fix the depth camera (11-3); the upper electromagnet seat, the slide, the upper servo seat (11-18), the lower electromagnet seat (11-10), and the lower servo seat are all fixed on the column (11-4); the upper servo seat (11-18) has a through hole at the end thereof for connecting the upper servo (11-18) to the upper servo seat. 1-17); the upper steering gear shaft is connected to the upper steering gear disc via a spline, the upper steering gear disc is fixedly connected to the upper steering gear rotating plate (11-16), the end of the upper steering gear rotating plate (11-16) is connected to the upper probe connecting rod fixing block (11-15), the upper probe connecting rod fixing block (11-15) has a square through hole for connecting the upper probe connecting rod (11-14), the end of the upper probe connecting rod (11-14) is fixedly connected to the upper probe housing (11-13), and the upper probe housing (11-13) is provided with an upper pressure sensor and an upper probe (11-12) from top to bottom; An upper electromagnet is arranged at the end of the upper electromagnet seat for powering on the upper steering gear (11-17); the servo motor (11-8) is connected to the slide table through the motor adapter seat (11-7), and the servo motor shaft is connected to the ball screw D (11-5) through a coupling; the slide block (11-6) passes through the ball screw D (11-5), one side of the slide block (11-6) is slidably connected to the slide table, and the other side of the slide block (11-6) is connected to one side of the slide adapter plate (11-9); the other side of the slide adapter plate (11-9) is connected to the lower electromagnet seat (11 -10) is connected to the lower servo seat; a lower electromagnet (11-11) is arranged at the end of the lower electromagnet seat (11-10) for powering on the lower servo; a through hole is opened at the end of the lower servo seat for connecting the lower servo; the lower servo shaft is connected to the lower servo disc through a spline, the lower servo disc is fixedly connected to the lower servo rotating plate, the end of the lower servo rotating plate is connected to the lower probe connecting rod fixing block, the lower probe connecting rod fixing block is opened with a square through hole for connecting the lower probe connecting rod, the end of the lower probe connecting rod is connected to the lower probe housing through a screw, and the lower probe housing is provided with a lower pressure sensor and a probe from bottom to top.

6. The multi-degree-of-freedom preload / interface stiffness in-situ measurement equipment according to claim 1, characterized in that: The distance measuring unit (9) has the following structure: the distance measuring unit (9) is fixed on the inner ring (4-1) of the slewing bearing through a clamping plate, the clamping plate is connected to the upper end of the upper support rod (9-12), the upper support rod (9-12) is located at the center of the inner ring (4-1) of the slewing bearing, the lower end of the upper support rod (9-12) is connected to the adapter block C (9-10), the adapter block C (9-10) is fixedly connected to the connecting seat (9-11), and the limit block (9-9) is fixedly connected to the adapter block C (9-10); the connecting seat (9-11) is horizontally arranged, and has a linear guide rail D (9-8) embedded therein, and the limit block (9-9) is located at one end of the outer side of the linear guide rail D (9-8); The other end of the outer side of the linear guide rail D (9-8) is provided with an adapter block A (9-1) through a slider connecting plate (9-2); the adapter block A (9-1) can slide along the guide rail; a lower support rod (9-3) is fixedly provided below the adapter block A (9-1); a connecting plate B (9-4) is fixed below the lower support rod (9-3); the connecting plate B (9-4) is connected to the adapter block B (9-5); an infrared distance measuring sensor (9-6) is connected to the adapter block B (9-5) through a sensor seat (9-7); the distance between the distance measuring sensor (9-6) and the rotor can be adjusted to facilitate measurement; and the limit block (9-9) plays a role in limiting the movement of the adapter block 9-1.

7. The multi-degree-of-freedom preload / interface stiffness in-situ measurement equipment according to claim 2, characterized in that: The ball screw first seat fixing frame (1-5) is used to fix the ball screw first seat (1-15) inside the Z-direction right guide rail base plate; the servo motor reduction head seat (1-16) is used to fix the servo motor reduction head (1-14) outside the Z-direction right guide rail base plate.

8. The multi-degree-of-freedom preload / interface stiffness in-situ measurement equipment according to claim 4, characterized in that: The ball screw fixing head seat A (7-12) and the ball screw fixing tail seat A (7-15) are fixed on the middle frame (7-1) to support the ball screw B (7-13); the driven ball screw fixing head seat A (7-5) and the driven ball screw fixing tail seat A (7-8) are fixed on the middle frame (7-1) to support the driven ball screw A (7-7).

9. The multi-degree-of-freedom preload / interface stiffness in-situ measurement equipment according to claim 4, characterized in that: The driven ball screw fixed tailstock B (12-1) and the driven ball screw fixed headstock B (12-4) are fixed on the base frame (12-8) to support the driven ball screw B (12-2); the upper ball screw fixed tailstock B (12-11) and the ball screw fixed headstock B (12-14) are fixed on the base frame (12-8) to support the ball screw C (12-13).

10. The measurement method using the multi-degree-of-freedom preload / interface stiffness in-situ measurement equipment of claim 1 is characterized in that: Here are the steps: (1) Centering stage: the rotor to be measured is placed in the area to be detected, the R degree of freedom motion unit (4) moves, driving the distance measuring unit (9) to rotate one circle with a step length of 90°, with the initial state being 0°, and the distance to the rotor to be measured is measured at four positions of 0°, 90°, 180°, and 270° respectively. During the rotation process, the X degree of freedom motion unit (7) and the Y degree of freedom motion unit (12) move, driving the distance measuring unit (9) to adjust the posture in the X and Y directions, so that the readings of the infrared distance measuring sensors (9-6) at the above four positions are equal after the final rotation. At this time, the preload force / interface stiffness measurement unit (11) is coaxial with the rotor to be measured, and the measurement work can be started; (2) Measurement preparation stage; the Z degree of freedom motion unit (1) moves, driving the base (1-7) to move along the negative direction of the Z axis, that is, the end preload force / interface stiffness measurement unit (11) moves downward, and before entering the rotor cavity, the upper and lower servos drive the upper and lower servo turn plates to rotate, so that the upper and lower servo turn plates are in a vertical state, the purpose of which is to avoid collision with the rotor to be measured during the descent process; after the lower probe passes through the entrance of the comb plate, the lower servo drives the lower servo turn plate to rotate counterclockwise, so that the lower probe surface is parallel to the surface to be measured; the upper servo (11-17) drives the upper servo turn plate (11-16) to rotate clockwise, so that the upper probe (11-12) surface is parallel to the surface to be detected; (3) Measurement process; the Z-degree-of-freedom motion unit (1) continues to move, driving the preload force / interface stiffness measurement unit (11) to continue to move downward until the upper probe (11-12) contacts the measured object, completing the measurement of the surface to be measured by the upper probe (11-12); the servo motor (11-8) moves, driving the lower probe connected to the slide block (11-6) to move upward along the Z axis, until the lower probe contacts the surface to be measured, completing the measurement of the surface to be measured by the lower probe; (4) Measurement end stage: After the measurement work is completed, the upper servo (11-17) drives the upper servo rotating plate (11-16) to rotate counterclockwise, so that the upper servo rotating plate (11-16) is in a vertical state; the lower servo drives the lower servo rotating plate to rotate 30° clockwise, and the Z degree of freedom motion unit (1) moves, driving the preload force / interface stiffness measurement unit (11) to move upward. During the upward movement, the lower servo continues to drive the lower servo rotating plate to rotate clockwise, and when passing through the comb plate, it is ensured that the lower servo rotating plate is in a vertical state; the entire preload force / interface stiffness measurement unit (11) is removed from the inner cavity of the rotor to be tested.

Images