A special tool for replacing the Boeing 737 aircraft pilot control stick needle bearing

Abstract

A kind of special tool for replacing Boeing 737 aircraft pilot control stick needle bearing, it relates to aircraft maintenance technical field, when needle bearing is needed to be disassembled, needle bearing dismounting mechanism is placed into operating lever bearing seat, power mechanism is operated, needle bearing is pulled out from mounting hole by needle bearing dismounting mechanism, and dismounting work is completed.New needle bearing is placed into operating lever bearing seat from the mounting hole of dismounting operating lever bearing seat, needle bearing mounting mechanism is placed into operating lever bearing seat, and new needle bearing is pressed into mounting hole by needle bearing mounting mechanism by power mechanism operation.New needle bearing is quickly and reliably installed in place by special tool, and the use of special tool can reduce maintenance operation risk, improve work efficiency, improve work quality and meet the requirements of maintenance manual.

Description

Technical Field

[0001] This utility model relates to the field of aircraft maintenance technology, specifically to a special tooling for replacing the needle roller bearing on the control stick of a Boeing 737 aircraft. Background Technology

[0002] According to Boeing's experience, the needle roller bearings on pilot control sticks can corrode due to various factors. Under normal conditions, corrosion of these bearings can lead to excessive control forces, significantly increasing pilot fatigue, reducing control precision, and diminishing the effectiveness of control actions. Therefore, Boeing has issued a service letter requiring operators to monitor for abnormal control stick force or delayed return to center. If rust, jamming, or worn needle rollers are found on the bearing surface, the control stick must be removed and the needle roller bearing replaced according to the aircraft maintenance manual.

[0003] The control lever employs a segmented structure, with the upper closed cylindrical cavity and bearing housing connected by solid rivets, and the internal wiring harness is densely packed. Because the bearing housing is located at the bottom of the control lever, its compact design severely limits operating space. Conventional manual hydraulic tools cannot easily access the needle roller bearing location, necessitating disassembly of the control lever for bearing replacement. However, disassembling the control lever requires removing the connecting solid rivets and disconnecting the internal wiring harness. This carries the risk of the rivets not being restored to their original state and damage to the wiring harness, compromising the strength and precision of the structural connections.

[0004] Boeing has not designed a dedicated replacement tool for this component. Sending it for repair would be time-consuming, increasing customer costs and impacting aircraft maintenance schedules. Currently, conventional manual hydraulic tools struggle to reach the bottom bearing location, requiring additional pulling tools, which is inefficient, risky, and can easily damage the control stick structure and needle roller bearings. Summary of the Invention

[0005] In order to overcome the shortcomings of the above technologies, this utility model provides a special tooling for replacing the needle roller bearings on the control stick of a Boeing 737 aircraft, which reduces the maintenance cycle of the aircraft, saves maintenance costs, and reduces construction risks.

[0006] The technical solution adopted by this utility model to overcome its technical problem is: A specialized tooling for replacing needle roller bearings on the control stick of a Boeing 737 aircraft includes: Needle roller bearing removal mechanism, used to remove the needle roller bearing from the mounting hole of the operating rod bearing housing; A needle roller bearing mounting mechanism for installing a new needle roller bearing into the mounting hole of the operating rod bearing housing; and The power mechanism is connected to the needle roller bearing disassembly mechanism and the needle roller bearing installation mechanism. The power mechanism drives the needle roller bearing disassembly mechanism to pull the needle roller bearing out of the mounting hole and drives the needle roller bearing installation mechanism to press the new needle roller bearing into the mounting hole.

[0007] Furthermore, the aforementioned power mechanism includes a cylinder body with an internal cavity in which a piston is slidably mounted. The cavity at the rear end of the piston forms an oil chamber. The cylinder body is provided with an oil port that communicates with the oil chamber. The oil port is connected to an oil pump and an oil tank respectively through a reversing valve. A sealing sleeve is sealed at the front opening of the cylinder body. A piston rod is coaxially mounted at the head end of the piston. The head end of the piston rod extends out of the sealing sleeve and is connected to a needle roller bearing disassembly mechanism or a needle roller bearing mounting mechanism. A spring is fitted onto the piston rod, with one end connected to the piston rod and the other end connected to the piston. When the spring is in a free state, the piston slides inward to the rear dead center.

[0008] Furthermore, the aforementioned needle roller bearing disassembly mechanism includes a disassembly sleeve, a screw, and a disassembly nut. The disassembly sleeve is inserted into the operating rod bearing housing through the connection port of the operating rod bearing housing. The rear end of the disassembly sleeve contacts the inner wall of the operating rod bearing housing. The disassembly sleeve has a through hole with the same axis as the needle roller bearing. The disassembly nut is placed at the rear end of the needle roller bearing. The outer diameter of the disassembly nut is larger than the inner diameter of the needle roller bearing. The front end of the screw is screwed into the screw hole of the disassembly nut. The screw is inserted into the through hole. A boss is provided in the middle part of the screw. The rear end of the screw passes through the inner hole of the piston rod and is locked by a nut. The front end face of the boss contacts the head end of the piston rod.

[0009] Furthermore, the aforementioned needle roller bearing mounting mechanism includes an external thread at the cylinder head end, a mounting sleeve coaxially screwed onto the cylinder body via the external thread, and a guide rod slidably inserted into the mounting sleeve. The rear end of the guide rod contacts the piston rod head end. The head end of the guide rod is provided with a flange, and the front end of the flange is provided with a plug I that matches the inner bore of the needle roller bearing. The head end of the mounting sleeve is inserted into the operating rod bearing seat through the connection port and then connected to the operating rod bearing seat via a positioning mechanism. The guide rod and the needle roller bearing are coaxial, the plug I is inserted into the inner bore of the needle roller bearing, and the front end face of the needle roller bearing contacts the flange.

[0010] A sealing ring is installed between the piston and the inner wall of the cylinder.

[0011] To improve the smoothness of disassembly, a plug II is coaxially provided on the inner end of the aforementioned disassembly nut. Both the disassembly nut and plug II are elliptical in shape. The major diameter of the ellipse of the disassembly nut is larger than the inner diameter of the needle roller bearing's inner hole, and the minor diameter of the ellipse of the disassembly nut is smaller than the inner diameter of the needle roller bearing's inner hole. The major diameter of the ellipse of plug II matches the inner diameter of the needle roller bearing's inner hole, and the minor diameter of the ellipse of plug II is smaller than the inner diameter of the needle roller bearing's inner hole.

[0012] To facilitate the removal of the needle roller bearing, the head end of the removal sleeve is provided with a receiving groove. When the needle roller bearing is pulled out of the mounting hole, it is inserted into the receiving groove.

[0013] Furthermore, the aforementioned positioning mechanism includes positioning pin holes respectively disposed on the left and right sides of the mounting sleeve. When the head end of the mounting sleeve is inserted into the operating rod bearing seat from the connection port of the operating rod bearing seat and the positioning hole on the operating rod bearing seat is aligned with the corresponding positioning pin hole on the same side, the rear pin passes through the positioning hole and the positioning pin hole in sequence.

[0014] The beneficial effects of this utility model are as follows: When it is necessary to disassemble the needle roller bearing, the needle roller bearing disassembly mechanism is placed into the bearing housing of the operating rod. The power mechanism then uses the needle roller bearing disassembly mechanism to pull the needle roller bearing out of the mounting hole, completing the disassembly work. A new needle roller bearing is then placed from the mounting hole of the disassembly operating rod bearing housing into the mounting hole of the operating rod bearing housing. The needle roller bearing mounting mechanism is then placed into the bearing housing of the operating rod, and the power mechanism then uses the needle roller bearing mounting mechanism to press the new needle roller bearing into the mounting hole. This achieves quick and reliable installation of the needle roller bearing. The use of specialized tooling reduces maintenance operation risks, improves work efficiency, enhances work quality, and meets the requirements of the maintenance manual. Attached Figure Description

[0015] Figure 1 This is a three-dimensional structural diagram of the present invention in the state of removing the needle roller bearing; Figure 2 This is a three-dimensional structural diagram of the present invention in the installation state of the needle roller bearing; Figure 3 This is a three-dimensional structural diagram of the nut removal method of this utility model; Figure 4 for Figure 1 AA-direction cross-sectional structure diagram; Figure 5 for Figure 2 BB-direction cross-sectional structure diagram In the diagram, 1. Operating rod bearing seat; 2. Positioning hole; 3. Removal sleeve; 4. Cylinder body; 5. Screw; 6. Nut; 7. Removal nut; 8. External thread; 9. Needle roller bearing; 10. Mounting sleeve; 11. Plug I; 12. Pin; 13. Screw hole; 14. Oil cavity; 15. Sealing ring; 16. Sealing sleeve; 17. Piston; 18. Piston rod; 19. Spring; 20. Oil port; 21. Mounting hole; 22. Through hole; 23. Receiving groove; 24. Guide rod; 25. Connection port; 26. Flange; 71. Plug II. Detailed Implementation

[0016] The following is in conjunction with the appendix Figure 1 To be continued Figure 5 The present invention will be further described below.

[0017] As attached Figure 1 and attached Figure 2 As shown, a special tooling for replacing needle roller bearings on a Boeing 737 aircraft pilot's control stick includes: a needle roller bearing removal mechanism for removing the needle roller bearing 9 from the mounting hole 21 of the control stick bearing housing 1; a needle roller bearing installation mechanism for installing a new needle roller bearing into the mounting hole 21 of the control stick bearing housing 1; and a power mechanism connected to the needle roller bearing removal mechanism and the needle roller bearing installation mechanism. The power mechanism drives the needle roller bearing removal mechanism to pull the needle roller bearing 9 out of the mounting hole 21 and drives the needle roller bearing installation mechanism to press the new needle roller bearing 9 into the mounting hole 21. When it is necessary to remove the needle roller bearing 9, the needle roller bearing removal mechanism is placed into the control stick bearing housing 1, and the power mechanism is activated to pull the needle roller bearing 9 out of the mounting hole 21 using the needle roller bearing removal mechanism, thus completing the removal work. The new needle roller bearing 9 is inserted from the mounting hole 21 of the operating rod bearing housing 1 into the mounting hole 21 of the operating rod bearing housing 1. The needle roller bearing mounting mechanism is then placed into the operating rod bearing housing 1. The power mechanism actuates to press the new needle roller bearing 9 into the mounting hole 21 using the needle roller bearing mounting mechanism. This achieves quick and reliable installation of the needle roller bearing 9. The use of specialized tooling reduces maintenance operation risks, improves work efficiency, enhances work quality, and meets the requirements of the maintenance manual.

[0018] In one embodiment of this utility model, the power mechanism includes a cylinder body 4, which has a cavity inside. A piston 17 is slidably installed in the cavity. The cavity at the rear end of the piston 17 forms an oil chamber 14. An oil port 20 is provided on the cylinder body 4 and communicates with the oil chamber 14. The oil port 20 is connected to the oil pump and the oil tank respectively through a reversing valve. A sealing sleeve 16 is sealed at the front opening of the cylinder body 4. A piston rod 18 is coaxially provided at the head end of the piston 17. The head end of the piston rod 18 extends out of the sealing sleeve 16 and is connected to the needle roller bearing disassembly mechanism or the needle roller bearing installation mechanism. A spring 19 is fitted on the piston rod 18. One end of the spring 19 is connected to the piston rod 18, and the other end is connected to the piston 17. When the spring 19 is in a free state, the piston 17 slides inward to the rear dead center. When the directional valve switches to connect the oil pump to port 20, the oil pump draws high-pressure hydraulic oil from the tank and delivers it to the oil chamber 14 through port 20. The hydraulic oil pushes the piston 17 forward and compresses the spring 19, causing the piston rod 18 to extend. The piston rod 18 drives the connected needle bearing mounting mechanism to install a new needle roller bearing into the mounting hole 21 of the operating rod bearing seat 1. When the directional valve switches to connect the tank to port 20, the spring 19 releases its elastic force, pushing the piston 17 backward. The hydraulic oil in the oil chamber 14 flows into the tank through port 20, causing the piston rod 18 to retract inward. The piston rod 18 drives the connected needle roller bearing removal mechanism to remove the needle roller bearing 9 from the mounting hole 21 of the operating rod bearing seat 1.

[0019] In one embodiment of this utility model, as shown in the appendix Figure 4 As shown, the needle roller bearing disassembly mechanism includes a disassembly sleeve 3, a screw 5, and a disassembly nut 7. The disassembly sleeve 3 is inserted into the operating rod bearing seat 1 through the connection port 25. The rear end of the disassembly sleeve 3 contacts the inner wall of the operating rod bearing seat 1. The disassembly sleeve 3 is provided with a through hole 22 that is coaxial with the needle roller bearing 9. The disassembly nut 7 is placed at the rear end of the needle roller bearing 9. The outer diameter of the disassembly nut 7 is larger than the inner diameter of the needle roller bearing 9. The front end of the screw 5 is screwed into the screw hole 13 of the disassembly nut 7. The screw 5 is inserted into the through hole 22. A boss is provided in the middle part of the screw 5. The rear end of the screw 5 passes through the inner hole of the piston rod 18 and is locked by the nut 6. The front end face of the boss contacts the head end of the piston rod 18. When the reversing valve switches to connect the oil tank and oil port 20, the spring 19 releases its elastic force, which pushes the piston 17 to move backward. The piston rod 17 drives the screw 5 to move backward. Since the front end of the screw 5 is threadedly connected to the removal nut 7, the screw 5 transmits the pulling force to the removal nut 7. The removal nut 7 is located at the rear end of the needle roller bearing 9. Therefore, the removal nut 7 applies force to the rear end of the needle roller bearing 9, pulling the needle roller bearing 9 out of the mounting hole 21, thus achieving the disassembly of the needle roller bearing 9.

[0020] In one embodiment of this utility model, as shown in the appendix Figure 5 As shown, the needle roller bearing mounting mechanism includes an external thread 8 at the head end of the cylinder 4, a mounting sleeve 10 coaxially screwed onto the cylinder 4 via the external thread 8, and a guide rod 24 slidably inserted into the mounting sleeve 10. The rear end of the guide rod 24 contacts the head end of the piston rod 18. The head end of the guide rod 24 is provided with a flange 26, and the front end of the flange 26 is provided with a plug I 11 that matches the inner hole of the needle roller bearing 9. The head end of the mounting sleeve 10 is inserted into the operating rod bearing seat 1 through the connection port 25 of the operating rod bearing seat 1 and then connected to the operating rod bearing seat 1 via a positioning mechanism. The guide rod 24 is coaxial with the needle roller bearing 9, and the plug I 11 is inserted into the inner hole of the needle roller bearing 9. The front end face of the needle roller bearing 9 contacts the flange 26. When the directional valve switches to connect the oil pump to port 20, the oil pump operates, drawing high-pressure hydraulic oil from the oil tank and delivering it to the oil chamber 14 through port 20. The hydraulic oil pushes the piston 17 forward, and the piston rod 18 pushes the guide rod 24 forward. Since the outer diameter of the flange 26 is larger than the inner diameter of the needle roller bearing 9, the flange 26 pushes the needle roller bearing 9 into the mounting hole 21. Because the plug I 11 is inserted into the inner hole of the needle roller bearing 9, it ensures that the needle roller bearing 9 always moves axially when inserted into the mounting hole 21, preventing eccentric loads from damaging the needle roller bearing 9.

[0021] In one embodiment of this invention, a sealing ring 15 is provided between the piston 17 and the inner wall of the cylinder 4. By providing the sealing ring 15, the sealing performance between the piston 17 and the cylinder 4 is improved.

[0022] In one embodiment of this utility model, a plug II 71 is coaxially provided on the inner end of the removal nut 7. Both the removal nut 7 and the plug II 71 are elliptical in shape. The major diameter of the ellipse of the removal nut 7 is larger than the inner diameter of the inner hole of the needle roller bearing 9, and the minor diameter of the ellipse of the removal nut 7 is smaller than the inner diameter of the inner hole of the needle roller bearing 9. The major diameter of the ellipse of the plug II 71 matches the inner diameter of the inner hole of the needle roller bearing 9, and the minor diameter of the ellipse of the plug II 71 is smaller than the inner diameter of the inner hole of the needle roller bearing 9. The removal nut 7 has an elliptical structure. Therefore, it can be used to insert the removal nut 7 into the operating rod bearing seat 1 from the connection port 25 by taking advantage of the fact that its minor diameter is smaller than the inner diameter of the needle roller bearing 9. Then, the removal nut 7 is inserted horizontally from the front end of the needle roller bearing 9. When the removal nut 7 reaches the rear end of the needle roller bearing 9, it is rotated to a vertical position and the plug II 71 of the removal nut 7 is inserted into the inner hole of the needle roller bearing 9. This facilitates the installation of the removal nut 7. Since the plug II 71 is inserted into the inner hole of the needle roller bearing 9, it can be ensured that the needle roller bearing 9 is always subjected to axial force during removal, preventing the needle roller bearing 9 from being stuck and difficult to remove due to eccentric load.

[0023] In one embodiment of this utility model, the head end of the removal sleeve 3 is provided with a receiving groove 23. When the needle roller bearing 9 is pulled out from the mounting hole 21, it is inserted into the receiving groove 23. After the removed needle roller bearing 9 is placed in the receiving groove 23, the removal sleeve 3 can be removed from the operating rod bearing seat 1, thereby making it easy to take the needle roller bearing 9 out of the operating rod bearing seat 1, which improves the convenience of operation.

[0024] In one embodiment of this utility model, the positioning mechanism includes positioning pin holes respectively disposed on the left and right sides of the mounting sleeve 10. When the head end of the mounting sleeve 10 is inserted into the operating rod bearing seat 1 through the connection port 25 of the operating rod bearing seat 1, and the positioning hole 2 on the operating rod bearing seat 1 is coaxial with the corresponding positioning pin hole on the same side, the pin 12 passes through the positioning hole 2 and the positioning pin hole in sequence. The pin 12 enables a quick positioning connection between the mounting sleeve 10 and the operating rod bearing seat 1, ensuring that the mounting sleeve 10 and the mounting hole 21 are coaxial, so that the needle roller bearing 9 is not subjected to eccentric load when pressed in.

[0025] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A special tooling for replacing needle roller bearings on the control stick of a Boeing 737 aircraft, characterized in that, include: Needle roller bearing removal mechanism for removing the needle roller bearing (9) from the mounting hole (21) of the operating rod bearing housing (1). A needle roller bearing mounting mechanism for mounting a new needle roller bearing into the mounting hole (21) of the operating rod bearing housing (1); and The power mechanism is connected to the needle roller bearing disassembly mechanism and the needle roller bearing installation mechanism. The power mechanism drives the needle roller bearing disassembly mechanism to pull the needle roller bearing (9) out of the mounting hole (21) and drives the needle roller bearing installation mechanism to press the new needle roller bearing (9) into the mounting hole (21).

2. The special tooling for replacing the needle roller bearing on the pilot control stick of a Boeing 737 aircraft according to claim 1, characterized in that: The power mechanism includes a cylinder (4) with a cavity inside. A piston (17) is slidably installed in the cavity. The cavity at the rear end of the piston (17) forms an oil chamber (14). An oil port (20) connected to the oil chamber (14) is provided on the cylinder (4). The oil port (20) is connected to the oil pump and the oil tank through a reversing valve. A sealing sleeve (16) is sealed at the front opening of the cylinder (4). A piston rod (18) is coaxially provided at the head end of the piston (17). The head end of the piston rod (18) extends out from the sealing sleeve (16) and is connected to the needle roller bearing disassembly mechanism or the needle roller bearing installation mechanism. A spring (19) is fitted on the piston rod (18). One end of the spring (19) is connected to the piston rod (18), and the other end is connected to the piston (17). When the spring (19) is in a free state, the piston (17) slides inward to the rear dead center.

3. The special tooling for replacing the needle roller bearing on the pilot control stick of a Boeing 737 aircraft according to claim 2, characterized in that: The needle roller bearing disassembly mechanism includes a disassembly sleeve (3), a screw (5), and a disassembly nut (7). The disassembly sleeve (3) is inserted into the operating rod bearing seat (1) through the connection port (25) of the operating rod bearing seat (1). The rear end of the disassembly sleeve (3) is in contact with the inner wall of the operating rod bearing seat (1). The disassembly sleeve (3) is provided with a through hole (22) with the same axis as the needle roller bearing (9). The disassembly nut (7) is placed at the rear end of the needle roller bearing (9). The outer diameter of the disassembly nut (7) is larger than the inner diameter of the needle roller bearing (9). The front end of the screw (5) is screwed into the screw hole (13) of the disassembly nut (7). The screw (5) is inserted into the through hole (22). A boss is provided in the middle part of the screw (5). The rear end of the screw (5) passes through the inner hole of the piston rod (18) and is locked by a nut (6). The front end face of the boss is in contact with the head end of the piston rod (18).

4. The special tooling for replacing the needle roller bearing on the pilot control stick of a Boeing 737 aircraft according to claim 2, characterized in that: The needle roller bearing mounting mechanism is provided with an external thread (8) at the head end of the cylinder (4), an mounting sleeve (10) coaxially screwed onto the cylinder (4) through the external thread (8), and a guide rod (24) slidably inserted into the mounting sleeve (10). The rear end of the guide rod (24) is in contact with the head end of the piston rod (18). The head end of the guide rod (24) is provided with a flange (26). The front end of the flange (26) is provided with a plug I (11) that matches the inner hole of the needle roller bearing (9). The head end of the mounting sleeve (10) is inserted into the operating rod bearing seat (1) through the connection port (25) of the operating rod bearing seat (1) and then connected to the operating rod bearing seat (1) through the positioning mechanism. The guide rod (24) is coaxial with the needle roller bearing (9). The plug I (11) is inserted into the inner hole of the needle roller bearing (9). The front end face of the needle roller bearing (9) is in contact with the flange (26).

5. The special tooling for replacing the needle roller bearing on the pilot control stick of a Boeing 737 aircraft according to claim 2, characterized in that: A sealing ring (15) is provided between the piston (17) and the inner wall of the cylinder (4).

6. The special tooling for replacing the needle roller bearing on the pilot control stick of a Boeing 737 aircraft according to claim 3, characterized in that: The inner end of the removal nut (7) is coaxially provided with a plug II (71). Both the removal nut (7) and the plug II (71) are elliptical in shape. The major diameter of the ellipse of the removal nut (7) is larger than the inner diameter of the inner hole of the needle roller bearing (9), and the minor diameter of the ellipse of the removal nut (7) is smaller than the inner diameter of the inner hole of the needle roller bearing (9). The major diameter of the ellipse of the plug II (71) matches the inner diameter of the inner hole of the needle roller bearing (9), and the minor diameter of the ellipse of the plug II (71) is smaller than the inner diameter of the inner hole of the needle roller bearing (9).

7. The special tooling for replacing the needle roller bearing on the pilot control stick of a Boeing 737 aircraft according to claim 3, characterized in that: The head end of the removal sleeve (3) is provided with a receiving groove (23), which is inserted into the receiving groove (23) after the needle roller bearing (9) is pulled out from the mounting hole (21).

8. The special tooling for replacing the needle roller bearing on the pilot's control stick of a Boeing 737 aircraft according to claim 4, characterized in that: The positioning mechanism includes positioning pin holes respectively set on the left and right sides of the mounting sleeve (10). When the head end of the mounting sleeve (10) is inserted into the operating rod bearing seat (1) from the connection port (25) of the operating rod bearing seat (1) and the positioning hole (2) on the operating rod bearing seat (1) is the same as the corresponding positioning pin hole on the same side, the pin (12) passes through the positioning hole (2) and the positioning pin hole in sequence.

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