Deep cavity visualization large nut tightening device and operation method for aero-engine rotor

Abstract

This invention discloses a deep-cavity visualization nut tightening device and its operation method for aero-engine rotors. The invention uses a positioning pin to determine the initial relative angular positional relationship between the nut tightening shaft and the spline positioning shaft, establishing a precise and rapid initial angular positional relationship between a toothed groove on the engine's large nut and a toothed groove at the end of the aero-engine rotor. The structure is simple and the operation is quick. An auxiliary positioning fixture is fixed to the aero-engine casing, assisting in inserting the nut tightening device into the center hole of the auxiliary positioning fixture, achieving rapid guidance and centering, and avoiding the risk of damaging engine parts. Based on the read angular deviation value, the invention inputs it into a servo motor controller to precisely drive the nut tightening shaft to move the engine's large nut, ensuring precise and rapid alignment between a toothed groove on the engine's large nut and a toothed groove at the end of the rotor. It is simple and easy to use.

Description

Technical Field

[0001] This invention belongs to the field of automated assembly technology for aero-engines, specifically relating to an aero-engine rotor deep cavity visualization large nut tightening device and its operation method. Background Technology

[0002] Aero-engine assembly is one of the most crucial steps in engine manufacturing. Its complex structure, limited assembly space, and high precision requirements, coupled with the large number of parts and complex coordination involved, directly impact the engine's operating characteristics, reliability, lifespan, and key performance parameters. Aero-engines have numerous high-torque threaded connections, typically tightened using traditional torque wrenches and multipliers. The installation of the large rotor nut is a key component, effectively connecting the engine's low-pressure turbine rotor's long shaft to a critical part of the low-pressure turbine compressor. Located 700-800mm from the engine port and in a deep cavity approximately 95mm in diameter on the engine belly, this installation requires precise alignment of the turbine shaft's circumferential slot with the nut's angular slot, and applying a tightening torque of 1900-2100 Nm – a highly challenging operation. Traditional installation methods cannot simultaneously perform installation operations and internal visual inspections of the operating parts. They can only use trial and error methods, which involve manual blind assembly and repeated disassembly and tightening of tools, as well as repeated internal visual inspections for confirmation. This is extremely inefficient, carries a high risk of tools colliding with engine parts, has a long assembly cycle, and cannot monitor whether the threaded fit is in place or whether it is seizing or other quality issues. Summary of the Invention

[0003] In order to improve the overall manufacturing technology level of my country's aero-engines and make up for the shortcomings in manufacturing process equipment, it is urgent to independently innovate and develop new technologies, methods and equipment suitable for the characteristics of my country's engine development process. The purpose of this invention is to provide a visual large nut tightening device and operation method for domestic aero-engine rotors, which has the characteristics of visualization, high precision, high efficiency and good safety, and reduces the labor intensity of operators; it is one of the important means to improve aero-engine assembly technology.

[0004] The technical solution of the present invention is as follows:

[0005] I. A Deep Cavity Visualized Large Nut Tightening Device for Aero-engine Rotors

[0006] The device includes a large nut tightening actuator, an auxiliary positioning fixture, and an assisting arm. The auxiliary positioning fixture is fixed on the casing of the aero-engine. The large nut tightening actuator is connected to the assisting arm, and the actuator end of the large nut tightening actuator is fitted with the engine's large nut. The assisting arm drives the actuator end of the large nut tightening actuator to insert into the center hole of the auxiliary positioning fixture, so that the actuator end of the large nut tightening actuator contacts the rotor end of the aero-engine. Then, under the control of the large nut tightening actuator, the engine's large nut is installed and tightened on the rotor end of the aero-engine.

[0007] The large nut tightening actuator includes a handwheel, a splined positioning shaft, a splined sleeve, a mounting base, a quick-change flange, a nut tightening shaft, a servo motor, a gear reducer, an engine large nut, a camera, a positioning pin, and a camera light source;

[0008] The mounting base is connected to the assist arm via a quick-change flange. A gear reducer is mounted on one side of the mounting base, and a servo motor is fixedly mounted under the mounting base. The output shaft of the servo motor is coaxially fixed to the input shaft of the gear reducer, and the output shaft of the gear reducer is coaxially fixed to the nut tightening shaft. A spline sleeve is rotatably mounted on the other side of the mounting base. A positioning pin is installed in the spline sleeve to position the rotation state of the spline sleeve. A spline positioning shaft is coaxially fixedly mounted inside the spline sleeve. One end of the spline positioning shaft extends out of the spline sleeve and is coaxially fixed to the handwheel. The two ends of the nut tightening shaft are connected inside the shaft. The other end of the spline positioning shaft passes through the mounting base and is located inside the nut tightening shaft. The spline positioning shaft and the nut tightening shaft are coaxial and spaced apart. The engine large nut is mounted on the end face of the nut tightening shaft away from the gear reducer. A camera and camera light source are fixedly mounted in the middle of the end face of the spline positioning shaft away from the handwheel. The end face of the spline positioning shaft away from the handwheel is in contact with the end of the aircraft engine rotor.

[0009] The end face of the nut tightening shaft away from the gear reducer is provided with a plurality of first mounting teeth arranged at equal intervals along the axial direction. The first mounting teeth of the nut tightening shaft are embedded in the toothed grooves corresponding to the end face of the engine large nut, so that when the nut tightening shaft drives the engine large nut to rotate, the nut tightening shaft and the engine large nut remain relatively stationary, thereby achieving angular positioning and transmitting tightening torque.

[0010] The spline positioning shaft is also provided with a plurality of second mounting teeth arranged circumferentially at intervals on one end face away from the handwheel. The plurality of second mounting teeth are fitted into the toothed grooves corresponding to the end face of the aero-engine rotor, so that after the end face of the spline positioning shaft away from the handwheel contacts and connects with the end face of the aero-engine rotor, the angular positioning of the aero-engine rotor is achieved.

[0011] II. Operation Method of a Deep Cavity Visualized Large Nut Tightening Device for Aero Engine Rotors

[0012] 1) Position the aircraft engine in a horizontal position, and then place the large nut of the engine to be installed into the end face of the nut tightening shaft away from the gear reducer.

[0013] 2) First, the actuator is driven by the assist arm to tighten the large nut and pass through the auxiliary positioning fixture. It extends into the deep cavity along the axis of the aero-engine rotor. Then, the miniature camera is turned on to observe the relative distance with the end of the aero-engine rotor. Next, the positioning pin is pulled out, and the spline positioning shaft is rotated by the handwheel and spline sleeve. The relative position between the spline positioning shaft and the aero-engine rotor is observed by the miniature camera. The spline positioning shaft is aligned with the end of the aero-engine rotor, so that the spline positioning shaft and the aero-engine rotor are relatively fixed.

[0014] 3) Fix the spline sleeve and spline positioning shaft with positioning pins to obtain the initial relative angular position between the aero-engine rotor and the nut tightening shaft;

[0015] 4) Start the servo motor, drive the nut tightening shaft to rotate through the gear reducer, and then screw the engine nut into the rotor of the aircraft engine.

[0016] In step 4), the tightening torque transmitted by the servo motor to the engine large nut is always set within a preset range. The servo motor calculates the relative angular deviation value based on the current relative angular position between the aero-engine rotor and the nut tightening shaft and the initial relative angular position. Based on the relative angular deviation value, it calculates the number of rotations, so that the tooth profile of the engine large nut is completely aligned with the tooth profile in the aero-engine rotor.

[0017] The advantages of this invention compared to the prior art are as follows:

[0018] 1) This invention uses a positioning pin to determine the initial relative angular position relationship between the nut tightening shaft and the spline positioning shaft, and establishes an initial angular position relationship for precise and rapid alignment between a certain toothed groove on the engine's large nut and a certain toothed groove at the end of the aero-engine rotor. The structure is simple and the operation is quick.

[0019] 2) In this invention, the auxiliary positioning fixture is fixed on the aircraft engine casing, and the large nut tightening device is inserted into the center hole of the auxiliary positioning fixture to achieve rapid guidance and centering positioning, avoiding the risk of bumping engine parts.

[0020] 3) Based on the angular deviation value read, the present invention inputs it into the servo motor controller to achieve precise drive of the nut tightening shaft to drive the engine large nut, so that a certain tooth groove on the engine large nut is precisely and quickly aligned with a certain tooth groove at the end of the rotor, which is simple and easy to use;

[0021] 4) This invention combines a servo motor controller drive with a miniature camera to simultaneously observe the status of the operating parts in real time and perform precise digital control operations, resulting in high precision, high efficiency, and low risk.

[0022] 5) This invention uses a power-assisted arm to grip and tighten large nuts, achieving semi-automatic operation. Unlike other technologies that use a fully automated gripping method with a robotic arm, this invention greatly reduces the risk of frequent collisions with engine parts caused by the low positioning accuracy of the robotic arm or the poor positioning accuracy of the AGV. Attached Figure Description

[0023] Figure 1 This is a working axis view of the deep cavity visualization large nut tightening device for aero-engine rotors;

[0024] Figure 2 This is a cross-sectional view of a deep cavity visualization large nut tightening device for an aero-engine rotor;

[0025] Figure 3 Axial view of the deep cavity visualization large nut tightening device for aero-engine rotor. Figure 1 ;

[0026] Figure 4 Axial view of the deep cavity visualization large nut tightening device for aero-engine rotor. Figure 2 ;

[0027] In the diagram: 1. Large nut tightening actuator; 2. Auxiliary positioning fixture; 3. Assist arm; 4. Aircraft engine; 101. Handwheel; 102. Splined positioning shaft; 103. Splined sleeve; 104. Mounting base; 105. Quick-change flange; 106. Nut tightening shaft; 107. Servo motor; 108. Gear reducer; 109. Engine large nut; 110. Camera; 111. Positioning pin; 112. Camera light source. Detailed Implementation

[0028] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0029] like Figure 1 As shown, the present invention includes a large nut tightening actuator 1, an auxiliary positioning fixture 2, and an assisting arm 3. The auxiliary positioning fixture 2 is fixed on the casing of the aero-engine 4. The quick-change flange 105 of the large nut tightening actuator 1 is connected to the assisting arm 3. The actuator end of the large nut tightening actuator 1 is fitted with a toothed engine large nut 109. The assisting arm 3 drives the actuator end of the large nut tightening actuator 1 to insert into the center hole of the auxiliary positioning fixture 2, so that the actuator end of the large nut tightening actuator 1 contacts the rotor end of the aero-engine 4. Then, under the control of the large nut tightening actuator 1, the engine large nut 109 is installed and tightened on the rotor end of the aero-engine 4.

[0030] like Figure 2 , Figure 3 and Figure 4As shown, the large nut tightening actuator 1 includes a handwheel 101, a splined positioning shaft 102, a splined sleeve 103, a mounting base 104, a quick-change flange 105, a nut tightening shaft 106, a servo motor 107, a gear reducer 108, an engine large nut 109, a miniature camera 110, a positioning pin 111, and a camera light source 112. The quick-change flange 105 is fixedly mounted on the mounting base 104, and the mounting base 104 is connected to the assist arm 3 through the quick-change flange 105. The gear reducer 108 is mounted on one side of the mounting base 104, and the servo motor 107 is fixedly mounted under the mounting base 104. The output shaft of the servo motor 107 is coaxially fixedly connected to the input shaft of the gear reducer 108, and the output shaft of the gear reducer 108 is coaxially fixedly connected to the nut tightening shaft 106. The input shaft and output shaft of the gear reducer 108 are not coaxial. Spline sleeve 103 is rotatably mounted on the other side of mounting base 104. A positioning pin 111 is installed in spline sleeve 103 to position the rotation of spline sleeve 103. A spline positioning shaft 102 is coaxially fixed inside spline sleeve 103. When positioning pin 111 is inserted into mounting base 104, spline sleeve 103 is fixedly mounted in mounting base 104, ultimately preventing the rotor of aero-engine 4 from rotating. When positioning pin 111 is separated from mounting base 104, spline sleeve 103 is rotatably mounted in mounting base 104, and the rotation of spline sleeve 103 drives the spline positioning shaft 102 to rotate. This invention uses positioning pin 111 to determine the initial relative angular positional relationship between nut tightening shaft 106 and spline positioning shaft 102. One end of the spline positioning shaft 102 extends from the spline sleeve 103 and is coaxially fixed to the handwheel 101. The two ends of the nut tightening shaft 106 are connected. The other end of the spline positioning shaft 102 passes through the mounting base 104 and the gear reducer 108 in sequence and is set inside the nut tightening shaft 106. The spline positioning shaft 102 and the nut tightening shaft 106 are coaxial and spaced apart. The end face of the nut tightening shaft 106 away from the gear reducer 108 is provided with a plurality of first mounting teeth arranged axially at equal intervals. The first mounting teeth are embedded in the toothed grooves corresponding to the end face of the engine nut 109, so that the engine nut 109 is installed on the end face of the nut tightening shaft 106 away from the gear reducer 108. During the tightening process of the engine nut 109, there is no relative displacement between the nut tightening shaft 106 and the engine nut 109, realizing angular positioning and transmitting tightening torque.The engine nut 109 does not contact the spline positioning shaft 102. A miniature camera 110 and a camera light source 112 are fixedly installed on the middle of the end face of the spline positioning shaft 102 away from the handwheel 101. The end face of the spline positioning shaft 102 away from the handwheel 101 is also provided with multiple second mounting teeth arranged circumferentially. The multiple second mounting teeth are embedded in the toothed grooves corresponding to the end of the aero-engine 4 rotor, so that after the end face of the spline positioning shaft 102 away from the handwheel 101 contacts and connects with the end of the aero-engine 4 rotor, the angular positioning of the aero-engine 4 rotor is achieved, and the two do not produce relative displacement.

[0031] A method for operating a deep cavity visualization large nut tightening device for an aero-engine rotor, the method comprising the following steps;

[0032] 1) Position the aircraft engine 4 in a horizontal position, and use the bolt holes on the edge of the casing to fix the auxiliary positioning fixture 2 onto the casing of the aircraft engine 4; use the assist arm 3 to grab the large nut through the quick-change flange 105 to tighten the actuator 1; then place the large nut 109 of the engine to be installed into the end face (front end) of the nut tightening shaft 106 away from the gear reducer 108 and mate it with the tooth groove, and insert the nut tightening shaft 106 into the center hole of the auxiliary positioning fixture 2 for centering and guiding positioning;

[0033] 2) First, the actuator 1 is driven by the drive arm 3 to tighten the large nut and pass through the auxiliary positioning fixture 2. It is then slowly extended into the deep cavity along the axial direction of the aero-engine 4 rotor. Next, the miniature camera 110 is turned on to observe the relative distance between the actuator 1 and the end of the aero-engine 4 rotor to avoid collision. Then, the two positioning pins 111 are pulled out. The spline positioning shaft 102 is rotated by the handwheel 101 and the spline sleeve 103, and the aero-engine 4 rotor is rotated. The relative position between the spline positioning shaft 102 and the aero-engine 4 rotor is observed by the miniature camera 110. The tooth profile of the end face of the spline positioning shaft 102 is aligned with the tooth groove at the end of the aero-engine 4 rotor, so that the spline positioning shaft 102 and the aero-engine 4 rotor are relatively fixed.

[0034] 3) Fix the spline sleeve 103 and spline positioning shaft 102 by two positioning pins 111 to obtain the initial relative angular position between the rotor of the aero-engine 4 and the nut tightening shaft 106;

[0035] 4) Start the servo motor 107, drive the nut tightening shaft 106 to rotate through the gear reducer 108, and then screw the engine large nut 109 into the rotor of the aircraft engine 4.

[0036] In step 4), the tightening torque transmitted by the servo motor 107 to the engine large nut 109 is always set within a preset range. The servo motor 107 calculates the relative angular deviation value based on the current relative angular position between the rotor of the aero-engine 4 and the nut tightening shaft 106 and the initial relative angular position. Based on the relative angular deviation value, it calculates the number of rotations, so that a certain toothed groove on the engine large nut 109 is precisely and quickly aligned with a certain toothed groove at the end of the aero-engine 4 rotor, and the engine large nut 109 is precisely and quickly screwed completely into the rotor of the aero-engine 4.

[0037] 5) Complete the installation and tightening of the engine large nut 109, disassemble the large nut tightening actuator 1 and auxiliary positioning fixture 2, etc., and repeat the preparation for the installation of the next aircraft engine.

[0038] Finally, it should be noted that the above embodiments and descriptions are only used to illustrate the technical solutions of the present invention and not to limit it. Those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the disclosure of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the protection scope of the claims of the present invention.

Claims

1. A deep-cavity visualization device for tightening large nuts on an aero-engine rotor, characterized in that, Includes a large nut tightening actuator (1), an auxiliary positioning fixture (2), and an assisting arm (3); The auxiliary positioning fixture (2) is fixed on the casing of the aero-engine (4). The large nut tightening actuator (1) is connected to the assist arm (3). The actuator end of the large nut tightening actuator (1) is fitted with the engine large nut (109). The assist arm (3) drives the actuator end of the large nut tightening actuator (1) to insert into the center hole of the auxiliary positioning fixture (2), so that the actuator end of the large nut tightening actuator (1) contacts the rotor end of the aero-engine (4). Then, under the control of the large nut tightening actuator (1), the engine large nut (109) is installed and tightened on the rotor end of the aero-engine (4). The large nut tightening actuator (1) includes a handwheel (101), a spline positioning shaft (102), a spline sleeve (103), a mounting base (104), a quick-change flange (105), a nut tightening shaft (106), a servo motor (107), a gear reducer (108), an engine large nut (109), a camera (110), a positioning pin (111), and a camera light source (112). The mounting base (104) is connected to the assist arm (3) via a quick-change flange (105). A gear reducer (108) is mounted on one side of the mounting base (104). A servo motor (107) is fixedly mounted under the mounting base (104). The output shaft of the servo motor (107) is coaxially fixed to the input shaft of the gear reducer (108). The output shaft of the gear reducer (108) is coaxially fixed to the nut tightening shaft (106). A spline sleeve (103) is rotatably mounted on the other side of the mounting base (104). A positioning pin (111) is installed in the spline sleeve (103). The positioning pin (111) is used to position the rotation state of the spline sleeve (103). A spline positioning shaft (102) is coaxially fixedly mounted inside the spline sleeve (103). One end of the shaft (102) extends out of the spline sleeve (103) and is coaxially fixed to the handwheel (101). The two ends of the nut tightening shaft (106) are connected. The other end of the spline positioning shaft (102) passes through the mounting base (104) and is set inside the nut tightening shaft (106). The spline positioning shaft (102) and the nut tightening shaft (106) are coaxial and spaced apart. The engine large nut (109) is installed on the end face of the nut tightening shaft (106) away from the gear reducer (108). The camera (110) and camera light source (112) are fixedly installed in the middle of the end face of the spline positioning shaft (102) away from the handwheel (101). The end face of the spline positioning shaft (102) away from the handwheel (101) is in contact with the end of the rotor of the aero-engine (4). The spline positioning shaft (102) is provided with a plurality of second mounting teeth arranged circumferentially at intervals on one end face away from the handwheel (101). The plurality of second mounting teeth are fitted into the toothed grooves corresponding to the end of the aero-engine (4) rotor, so that after the end face of the spline positioning shaft (102) away from the handwheel (101) is in contact with the end of the aero-engine (4) rotor, the angular positioning of the aero-engine (4) rotor is realized.

2. The deep cavity visualization large nut tightening device for aero-engine rotor according to claim 1, characterized in that, The end face of the nut tightening shaft (106) away from the gear reducer (108) is provided with a plurality of first mounting teeth arranged at equal intervals along the axial direction. The first mounting teeth of the nut tightening shaft (106) are embedded in the toothed grooves corresponding to the end face of the engine nut (109), so that during the rotation of the engine nut (109) driven by the nut tightening shaft (106), the nut tightening shaft (106) and the engine nut (109) remain relatively stationary, thereby achieving angular positioning and transmitting tightening torque.

3. The operating method of the deep cavity visualization large nut tightening device for aero-engine rotor according to claim 1 or 2, characterized in that, The operation method includes the following steps; 1) Position the aircraft engine (4) in a horizontal position, and then place the engine nut (109) to be installed into the end face of the nut tightening shaft (106) away from the gear reducer (108); 2) First, the actuator (1) is tightened by the large nut driven by the assist arm (3) through the auxiliary positioning fixture (2) and extended into the deep cavity along the rotor axis of the aero-engine (4). Then, the camera (110) is turned on to observe the relative distance with the end of the aero-engine (4) rotor. Then, the positioning pin (111) is pulled out, and the spline positioning shaft (102) is rotated by the handwheel (101) and the spline sleeve (103). The relative position between the spline positioning shaft (102) and the aero-engine (4) rotor is observed by the camera (110), so that the spline positioning shaft (102) is aligned with the end of the aero-engine (4) rotor, so that the spline positioning shaft (102) and the aero-engine (4) rotor are relatively fixed. 3) Fix the spline sleeve (103) and spline positioning shaft (102) by fixing the positioning pin (111) to obtain the initial relative angular position between the rotor of the aero-engine (4) and the nut tightening shaft (106); 4) Start the servo motor (107), drive the nut tightening shaft (106) to rotate through the gear reducer (108), and then screw the engine large nut (109) into the rotor of the aircraft engine (4).

4. The operating method of the deep cavity visualization large nut tightening device for aero-engine rotor according to claim 3, characterized in that, In step 4), the tightening torque transmitted by the servo motor (107) to the engine large nut (109) is always set within a preset range. The servo motor (107) calculates the relative angular deviation value based on the current relative angular position between the rotor of the aero-engine (4) and the initial relative angular position of the nut tightening shaft (106), and calculates the number of rotations based on the relative angular deviation value, so that the tooth profile of the engine large nut (109) is completely aligned with the tooth profile in the rotor of the aero-engine (4).

Images