Pulling tool for sealing front lip of APU gearbox and replacement method

Abstract

The invention relates to the technical field of aviation gear box maintenance, and provides a puller tool for sealing a front lip of an APU gear box and a replacement method, the puller tool for sealing the front lip of the APU gear box comprises a puller barrel, the outer wall of one end of the puller barrel is provided with an external thread, and the inner wall of the other end of the puller barrel is provided with an internal thread; the jacking cushion block is movably arranged in the inner cavity of the puller barrel; the gear fixing cushion block comprises a flange plate and a boss, and the screw rod is screwed in and is movably connected with the internal thread on the inner wall of the puller barrel; under the condition that the front lip seal is detached, the flange plate is fixed to a flange installation face on the peripheral side of the clutch installation cavity, the boss penetrates through the clutch installation cavity to abut against the gear, the external thread end of the puller barrel is connected with a threaded hole in the front lip seal cavity through a front lip seal operation hole, one end of the jacking cushion block abuts against a gear shaft, and the other end of the jacking cushion block abuts against the gear shaft. And the other end of the jacking cushion block is propped against the screw-in screw rod. And through cooperative operation of the gear fixing cushion block and the jacking cushion block, the replacement efficiency of the front lip seal is improved.

Description

Technical Field

[0001] The present application relates to the technical field of aviation gearbox maintenance, and in particular to a tooling and replacement method for a front lip seal of an APU gearbox. Background Art

[0002] Currently, the traditional APS3200 APU gearbox front lip seal replacement process requires the collaboration of three operators. The first operator removes the front lip seal, the second operator reaches through the clutch mounting cavity to secure the gear to prevent movement, and the third operator passes the tool. The operator uses a puller through the front lip seal operation hole to screw into the threaded hole of the front lip seal cavity and forcibly remove the front lip seal. The drawbacks of this operation design are: because the gear fits tightly with the front lip seal cavity, the impact force at the moment of extraction can easily cause the gear shaft to be pulled out, requiring the gear to be reinstalled; the operator needs to manually press the hot gear, which poses a risk of burns and requires wearing heavy gloves, making the construction uncomfortable; the three-person collaboration efficiency is low in the narrow tail cabin space, and the gear shaft height must be repeatedly verified during the extraction process to prevent improper installation. The above-mentioned drawbacks result in high operational risks, strong dependence on personnel, and long maintenance cycles in the existing disassembly process, which restricts the improvement of APU on-wing maintenance efficiency. Summary of the Invention

[0003] This application aims to at least solve the technical problems in the related art, such as high operational risk, strong dependence on personnel, and long maintenance cycle in the traditional APS3200 model APU gearbox front lip seal replacement process, which restrict the improvement of APU on-wing maintenance efficiency.

[0004] In order to solve the above technical problems, this application is implemented as follows:

[0005] The gear box is provided with a front lip seal operating hole and a clutch mounting cavity perpendicular to each other, a gear and a front lip seal are provided in the gear box, and a gear shaft of the gear is inserted into the cavity of the front lip seal. The puller tool comprises: a puller cylinder, an outer wall of one end of the puller cylinder is provided with an outer thread, and an inner wall of the other end is provided with an inner thread; a push-in pad movably arranged in the inner cavity of the puller cylinder; a gear fixing pad, the gear fixing pad comprising a flange and a boss, the boss extending along the axial direction of the flange; a screw-in screw movably connected to the inner thread of the inner wall of the puller cylinder; wherein, when the front lip seal is removed, the flange is fixed to the flange mounting surface on the peripheral side of the clutch mounting cavity, the boss passes through the clutch mounting cavity and presses against the gear, the outer thread end of the puller cylinder is connected to the threaded hole on the front lip seal cavity through the front lip seal operating hole, one end of the push-in pad abuts against the gear shaft, and the other end of the push-in pad abuts against the screw-in screw.

[0006] The APU gearbox front lip seal extraction tool provided in this application utilizes a dual tooling design with independent vertical operating holes to achieve simultaneous operation of gear fixing and front lip seal removal. Specifically, the tooling module comprises a first tooling module, which includes a gear fixing pad with a flange and a boss, secured to the flange surface of the clutch mounting cavity by bolts. The boss extends through the clutch mounting cavity and presses against the gear surface, replacing manual pressure. The second tooling module comprises a puller barrel, a nylon stepped cylindrical push pad, and a seal ejection assembly with a screw thread. The small diameter section of the push pad is inserted into the center hole of the gear shaft, while the large diameter section is pushed by the screw thread. The puller barrel is screwed into the threaded hole of the front lip seal cavity through the front lip seal operating hole. The screw thread is rotated to push the push pad against the gear shaft, and then ejected from the front lip seal cavity in the opposite direction, completing the front lip seal replacement operation. This application adopts a dual-hole independent operation design. The gear fixing pad is installed and fixed to the gear through the clutch mounting cavity, and the seal ejection assembly removes the seal through the vertical front lip seal operation hole. The two operation paths cooperate with each other to realize the rapid replacement of the front lip seal of the APS3200 model APU gearbox.

[0007] Moreover, the puller tooling design with a sealed front lip of the APU gearbox provided in this application eliminates the risk of gear movement through the gear fixing pads, and the nylon jacking pads cushion the jacking force and protect the gear shaft; the double tooling works together to reduce the number of operators to one, shortening the construction time and reducing the construction difficulty; there is no need to verify the gear height, reducing the process steps; and avoiding human contact with high-temperature components, fundamentally solving the problems of low efficiency, high operating risks and unstable maintenance quality caused by the traditional process's reliance on manual intervention.

[0008] In a second aspect, the present application proposes a method for replacing the front lip seal of an APU gearbox, using the puller tool for pulling the front lip seal of the APU gearbox in the above-mentioned scheme. The replacement method includes: removing the clutch cover and clutch on the gearbox to expose the flange mounting surface and the gear; fixing the flange plate of the gear fixing pad to the flange mounting surface with bolts, so that the boss passes through the clutch mounting cavity and presses against the gear; inserting the first diameter section of the push-in pad into the center hole of the shaft head of the gear shaft; screwing the external threaded end of the puller barrel into the threaded hole of the cavity of the front lip seal; rotating the screw rod to push the second diameter section to press against the gear shaft until the front lip seal is pushed out; and replacing the front lip seal.

[0009] The method for replacing the APU gearbox front lip seal provided in this application adopts the APU gearbox front lip seal pulling tool in the above-mentioned technical solution, and therefore has all the beneficial effects of the APU gearbox front lip seal pulling tool, which will not be repeated here.

[0010] Additional aspects and advantages of the present application will become apparent in the following description or may be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0012] Figure 1 This is a schematic diagram of the structure of a tool for removing the front lip seal of an APU gearbox according to one embodiment of the present application;

[0013] Figure 2 This is a second structural diagram of a tool for removing the front lip seal of an APU gearbox according to an embodiment of the present application;

[0014] Figure 3 This is a schematic structural diagram of a jacking pad in a tooling for pulling out the front lip seal of an APU gearbox according to one embodiment of the present application;

[0015] Figure 4 This is a schematic structural diagram of a gear fixing pad in a tooling for pulling out the front lip seal of an APU gearbox according to one embodiment of the present application;

[0016] Figure 5 This is a schematic structural diagram of a front lip sealing operation hole in an APU gearbox according to one embodiment of the present application;

[0017] Figure 6 This is a schematic structural diagram of a clutch mounting cavity in an APU gearbox according to one embodiment of the present application;

[0018] Figure 7 This is a flow chart of a method for replacing the front lip seal of an APU gearbox according to one embodiment of the present application.

[0019] in, Figures 1 to 7 The corresponding relationship between the reference numerals and component names is as follows:

[0020] 100APU gearbox front lip seal pulling tool, 110 pulling tool cylinder, 120 jacking pad, 122 first diameter section, 124 second diameter section, 130 gear fixing pad, 132 flange, 134 boss, 136 connecting hole, 138 positioning hole, 140 screw-in screw, 200 gearbox, 202 front lip seal operating hole, 204 clutch mounting cavity, 206 gear, 208 front lip seal, 210 gear shaft, 212 threaded hole, 214 flange mounting surface, 216 locating pin. DETAILED DESCRIPTION

[0021] In order to more clearly understand the above-mentioned objects, features and advantages of the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features therein can be combined with each other in the absence of conflict.

[0022] In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present application is not limited to the specific embodiments disclosed below.

[0023] Refer to the following Figures 1 to 7 The following describes an APU gearbox front lip seal removal tool 100 and an APU gearbox front lip seal replacement method provided in accordance with some embodiments of the present application.

[0024] like Figures 1 to 7 As shown, Figure 1 This is a schematic diagram of the structure of a tool 100 for removing the front lip seal of an APU gearbox according to an embodiment of the present application; Figure 2 This is a second structural diagram of a tool 100 for removing the front lip seal of an APU gearbox according to an embodiment of the present application; Figure 3 This is a structural schematic diagram of a jacking pad 120 in a tool 100 for pulling out the front lip seal of an APU gearbox according to an embodiment of the present application; Figure 4 This is a structural diagram of a gear fixing pad 130 in a tool 100 for sealing the front lip of an APU gear box according to an embodiment of the present application; Figure 5 This is a structural diagram of a front lip sealing operation hole 202 in an APU gearbox according to an embodiment of the present application; Figure 6 This is a schematic structural diagram of the clutch mounting cavity 204 in the APU gearbox according to one embodiment of the present application; Figure 7 This is a flow chart of a method for replacing the front lip seal of an APU gearbox according to one embodiment of the present application.

[0025] According to the first aspect of this application, Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 and Figure 6As shown, an embodiment of the present application provides a tool 100 for extracting the front lip seal of an APU gearbox. The gearbox 200 is provided with a front lip seal operating hole 202 and a clutch mounting cavity 204 that are perpendicular to each other. A gear 206 and a front lip seal 208 are provided in the gearbox 200. The gear shaft 210 of the gear 206 is inserted into the cavity of the front lip seal 208. The tool 100 includes: a tool cylinder 110, the outer wall of which is provided with an external thread at one end and the inner wall of which is provided with an internal thread at the other end; a jacking pad 120, which is movably arranged in the inner cavity of the tool cylinder 110; a gear fixing pad 130, which includes a flange 1 32 and boss 134, the boss 134 extends along the axial direction of the flange 132; screw in the screw 140 and movably connect it with the internal thread of the inner wall of the puller cylinder 110; wherein, when the front lip seal 208 is removed, the flange 132 is fixed to the flange mounting surface 214 on the peripheral side of the clutch mounting cavity 204, the boss 134 passes through the clutch mounting cavity 204 and presses against the gear 206, the external threaded end of the puller cylinder 110 passes through the front lip seal operating hole 202 and is connected to the threaded hole 212 on the cavity of the front lip seal 208, one end of the jacking pad 120 abuts against the gear shaft 210, and the other end of the jacking pad 120 abuts against the screw 140.

[0026] Specifically, if Figure 5 and Figure 6 As shown, an APU (Auxiliary Power Unit) gearbox 200 primarily comprises a gearbox housing, a gear 206, a front lip seal 208, and a sensor. The housing of the gearbox 200 is provided with a front lip seal operating hole 202 and a clutch mounting cavity 204, interconnected and with axes perpendicular to each other. It can be understood that the front lip seal operating hole 202 is an operating hole set on the shell for disassembling and replacing the front lip seal 208 and other components. The clutch mounting cavity 204 is the mounting port for installing the clutch, that is, after removing the clutch, the sides of the gear 206 and the front lip seal 208 can be seen through the mounting port. The front lip seal operating hole 202 and the clutch mounting cavity 204 are perpendicular to each other. It can be understood that the mounting port of the clutch mounting cavity 204 is set to the side of the front lip seal operating hole 202 in the vertical direction. The mounting port of the clutch mounting cavity 204 and the front lip seal operating hole 202 are two independent holes connected to each other. In this way, when the front lip seal 208 is removed through the front lip seal operating hole 202, the gear 206 can be fixed through the mounting port of the clutch mounting cavity 204 to prevent the gear 206 from moving or being brought out.

[0027] Specifically, if Figure 1 、 Figure 2 、 Figure 3 and Figure 4As shown, the APU gearbox front lip seal puller 100 includes a puller barrel 110, a jacking pad 120, a gear fixing pad 130, and a screw 140. The puller barrel 110 has an external thread on one end and an internal thread on the other end. In other words, the puller barrel 110 can be understood as a straight tube puller with external threads on one end and internal threads on the other end. The inner cavity of the puller barrel 110 is a hollow structure. The jacking pad 120 is movably arranged in the inner cavity of the puller cylinder 110, that is, the jacking pad 120 can slide up and down in the inner cavity of the puller cylinder 110; the gear fixing pad 130 includes a flange 132 and a boss 134, and the boss 134 extends along the axial direction of the flange 132, that is, the gear fixing pad 130 is an integrated stepped cylindrical pad; the screw-in screw 140 is movably connected with the internal thread of the inner wall of the puller cylinder 110, that is, the external thread of the screw-in screw 140 is screwed in cooperation with the internal thread of the puller cylinder 110, and the screw-in screw 140 can be screwed in or out along the length direction of the puller cylinder 110, so that the jacking pad 120 can be pushed to slide along the inner cavity of the puller cylinder 110. In this way, when the front lip seal 208 is removed, the flange 132 of the gear fixing pad 130 is fixed to the flange mounting surface 214 on the peripheral side of the clutch mounting cavity 204, and the boss 134 of the gear fixing pad 130 passes through the clutch mounting cavity 204 and presses against the gear 206, thereby auxiliary fixing the gear 206 and preventing the gear 206 from moving. The external threaded end of the puller cylinder 110 is connected to the threaded hole 212 on the cavity of the front lip seal 208 through the front lip seal operating hole 202, and one end of the push-in pad 120 abuts against the gear shaft 210, and the other end of the push-in pad 120 abuts against the screw-in screw 140. In this way, when the screw-in screw 140 continues to be rotated, the puller cylinder 110 The front lip seal 208 will be pulled out of the gear box 200. Since the jacking pad 120 is against the gear shaft 210, the gear shaft 210 and the gear 206 will not be brought out of the gear box 200 along with the front lip seal 208, thereby realizing the separate disassembly of the front lip seal 208. This disassembly process only requires one operator to complete. Since the gear fixing pad 130 is provided, the gear 206 can be fixed from the side, which is equivalent to an operator holding the gear 206 with his hand during the original disassembly process, eliminating the operator's auxiliary work, saving time and effort, and fixing the gear 206 by the gear fixing pad 130 is no longer affected by the temperature of the gear 206, thereby improving the disassembly efficiency of the disassembly operation.

[0028] Specifically, the gearbox is currently a crucial component of the auxiliary power unit (APU). It primarily consists of a gearbox housing, gears, seals, and various sensors. The front lip seal plays a crucial role. Whether on-wing or removed from the APU, oil leaks from the gearbox front lip seal are common, leading to abnormalities such as high lubricant consumption. Due to the instability of the front lip seal, the process and tooling used for replacing the front lip seal on-wing APUs are particularly important. The current method for replacing the front lip seal involves a first worker removing the clutch cover, removing the clutch, and exposing the mounting opening of the clutch mounting cavity. A second worker then manually secures the gear connected to the front lip seal, continuing this operation until the work is complete. The worker then measures the height difference between the gear shaft and the front lip seal cover to verify that the gear has not been removed. Due to the limited space in the aft compartment, the tooling used by the first worker during the replacement process requires a third worker to transfer the tools to complete the task.

[0029] Currently, the method for removing the front lip seal of the APS3200 model APU gearbox has the following disadvantages: (1) The replacement process requires the cooperation of three workers to complete. When performing this operation on the wing APU, the small space in the APU tail compartment and the three workers will increase the construction difficulty. (2) The replacement of the front lip seal of the wing APU is usually carried out shortly after the aircraft lands. The temperature of the APU that has just finished running is high, and the temperature of the gears is high, which will cause certain difficulties for the second worker to operate. (3) The instantaneous force when using the existing tool to extract the front lip seal can be large or small, which may cause the gear held down by another worker to be pulled out, which is extremely challenging for the workers' skills and has certain instability. (4) Since three workers need to cooperate with each other, it is time-consuming and labor-intensive, and the time required to complete the replacement will be extended.

[0030] In order to solve the shortcomings of the existing technology, Figure 1 and Figure 2As shown, the APU gearbox front lip seal removal tool 100 provided in this application realizes the simultaneous operation of gear fixing and front lip seal 208 removal through the design of dual tooling cooperation and independent operation of vertical operation holes. Specifically, it includes: the first tooling module is a gear fixing pad 130 including a flange 132 and a boss 134, which is fixed to the peripheral mounting surface 214 of the clutch mounting cavity 204 by bolts. The boss 134 passes through the clutch mounting cavity 204 and presses against the surface of the gear 206, replacing manual pressure. The second tooling module comprises a puller barrel 110, a nylon-made stepped cylindrical push pad 120, and a seal ejection assembly comprising a screw 140. The small-diameter section of the push pad 120 is inserted into the center hole of the gear shaft 210, while the large-diameter section is pushed by the screw 140. The puller barrel 110 is screwed into the threaded hole 212 of the front lip seal 208 through the front lip seal operation hole 202. The screw 140 is rotated to push the push pad 120 against the gear shaft 210, and the front lip seal 208 is ejected in the opposite direction, completing the replacement of the front lip seal 208. This application utilizes a dual-hole independent operation design: the gear fixing pad 130 installs and secures the gear through the clutch mounting cavity 204, while the seal ejection assembly removes the front lip seal 208 through the front lip seal operation hole 202. These two operation paths work together to achieve rapid replacement of the front lip seal of the APS3200 APU gearbox.

[0031] Moreover, the puller tool 100 design with a sealed front lip of the APU gearbox provided in the present application eliminates the risk of gear 206 moving through the gear fixing pad 130, and the nylon jacking pad 120 cushions the ejection force and protects the gear shaft 210; the dual tooling cooperates to reduce the number of operators to one, shortening the construction time and reducing the construction difficulty; there is no need to verify the gear height, reducing the process steps; and avoiding human contact with high-temperature components, fundamentally solving the problems of low efficiency, high operation risk, and unstable maintenance quality caused by the traditional process's reliance on manual intervention.

[0032] In a specific application, the APU gearbox front lip seal pulling tool 100 can be specifically a pulling tool for replacing the gearbox front lip seal of an APS3200 model APU on-wing or a pulling tool for replacing the gearbox front lip seal of an APS3200 model APU on-wing, and is used in the field of APU maintenance of civil aviation aircraft Airbus A320 series.

[0033] In some embodiments, optionally, as Figure 1 and Figure 3 As shown, the jacking pad 120 is a stepped cylindrical shape, and the jacking pad 120 includes a first diameter section 122 and a second diameter section 124, and the first diameter section 122 is coaxially connected to the second diameter section 124; when the front lip seal 208 is removed, the first diameter section 122 abuts or is inserted into the end of the gear shaft 210, and the second diameter section 124 abuts against the screw 140.

[0034] Specifically, if Figure 3 As shown, by setting the jacking pad 120 to be a stepped cylindrical shape, the jacking pad 120 includes a first diameter section 122 and a second diameter section 124 that are coaxially connected. In this way, when the front lip seal 208 is removed, the first diameter section 122 abuts or is inserted on the end of the gear shaft 210, and the second diameter section 124 abuts against the screw-in screw 140. The outer diameter of the first diameter section 122 is smaller than the inner diameter of the center hole at the end of the gear shaft 210, and the length is greater than the depth of the center hole, thereby achieving precise plug-in positioning; during the pushing process of the screw-in screw 140, impact force buffering and uniform axial force transmission are achieved, ensuring that the gear shaft 210 is not displaced by the ejection force, and completely avoiding the risk of the gear 206 being brought out due to the traditional extraction method.

[0035] In a specific application, the first diameter section 122 can be specifically set as a small diameter section of the outer circle, and the second diameter section 124 can be set as a large diameter section of the outer circle. The selection can be made according to actual usage and will not be listed here.

[0036] In some embodiments, optionally, as Figure 1 and Figure 3 As shown, the outer diameter of the first diameter section 122 is smaller than the outer diameter of the second diameter section 124 , the outer wall of the second diameter section 124 is clearance-matched with the inner cavity of the puller barrel 110 , and the height of the second diameter section 124 is greater than the maximum stroke of the screw 140 screwed into the puller barrel 110 .

[0037] Specifically, if Figure 3 As shown, the clearance between the second diameter section 124 and the inner cavity of the puller barrel 110 eliminates radial wobbling, ensuring a smooth push-out process. The height of the second diameter section 124 is greater than the maximum screw-in stroke of the screw 140, ensuring that the screw 140 can continue to transmit axial thrust through the second diameter section 124 even at its maximum stroke, thus avoiding interruptions in push-out caused by insufficient thread travel in conventional pullers. The outer diameter of the first diameter section 122 is smaller than that of the second diameter section 124, forming a stepped structure. The push-out block 120 coaxially contacts the end face of the gear shaft 210, preventing local stress concentration. This coordinated dimensional design fundamentally ensures that the ejection force acts continuously, stably, and evenly on the axial direction of the gear shaft 210, completely eliminating the risk of the gear being accidentally pulled out.

[0038] In a specific application, the length of the second diameter section 124 is 47 mm, the diameter of the second diameter section 124 is 12 mm, the length of the first diameter section 122 is 9.5 mm, and the diameter of the second diameter section 124 is 7.8 mm. The selection can be made based on actual usage and will not be listed here.

[0039] In some embodiments, optionally, as Figure 1 and Figure 4As shown, the height of the boss 134 in the gear fixing pad 130 is adapted to the distance from the gear 206 to the flange mounting surface 214 on the peripheral side of the clutch mounting cavity 204, and a supporting portion is provided at the end of the boss 134 close to the gear 206, and the shape of the supporting portion is adapted to the surface shape of the gear 206.

[0040] Specifically, if Figure 4 As shown, the height of boss 134 is equal to the axial distance from the surface of gear 206 to flange mounting surface 214, achieving zero-gap press-fitting of the end of boss 134 against the surface of gear 206 after installation. The abutment portion is designed as a concave arc surface that matches the curvature of the tooth groove on the outer edge of gear 206, automatically engaging the tooth gaps when the bolts tighten flange 132, forming a multi-point engagement. This eliminates the elastic deformation caused by traditional manual pressing, providing a constant locking force to prevent lateral movement of gear shaft 210; dispersing contact stress to prevent point loads from damaging the gear surface; and the concave arc surface guides the gear to automatically center, overcoming installation positioning deviations caused by the limited space in the tail compartment, ultimately achieving full circumferential rigid fixation of gear 206 and eliminating the risk of gear 206 displacement caused by unstable manual pressing in traditional processes.

[0041] In some embodiments, optionally, as Figure 4 As shown, the gear fixing pad 130 is provided with a plurality of connection holes 136 , which are evenly distributed on the flange 132 and are used to be connected and fixed to the flange mounting surface 214 on the peripheral side of the clutch mounting cavity 204 .

[0042] Specifically, if Figure 4 As shown, the gear fixing pad 130 is provided with a plurality of connecting holes 136, and the plurality of connecting holes 136 are evenly distributed on the flange plate 132, which are used to be connected and fixed with the flange mounting surface 214 on the peripheral side of the clutch mounting cavity 204. By providing a plurality of connecting holes 136 on the flange plate 132 of the gear fixing pad 130, the plurality of connecting holes 136 can correspond to the threaded holes 212 on the flange mounting surface 214 on the peripheral side of the clutch mounting cavity 204, thereby realizing the connection and fixation of the gear fixing pad 130 to the flange mounting surface 214 on the peripheral side of the clutch mounting cavity 204, thereby realizing the fixation of the gear 206 and preventing the gear 206 from moving.

[0043] In specific applications, three connecting holes 136 are set on the flange 132 of the gear fixing pad 130, and the connecting holes 136 are specifically threaded holes. Five threaded holes are set on the flange mounting surface 214 on the peripheral side of the clutch mounting cavity 204. The three threaded holes set on the flange 132 correspond to three of the five threaded holes set on the flange mounting surface 214 on the peripheral side of the clutch mounting cavity 204. The specific selection can be made according to actual usage and will not be listed here.

[0044] In some embodiments, optionally, as Figure 4As shown, the gear fixing pad 130 further includes a positioning hole 138 , which is provided on the flange 132 and is used to cooperate with a positioning pin 216 on the flange mounting surface 214 on the peripheral side of the clutch mounting cavity 204 for positioning.

[0045] Specifically, the gear fixing block 130 further includes a positioning hole 138. The positioning hole 138 is provided on the flange 132, and a positioning pin 216 is provided on the flange mounting surface 214 on the peripheral side of the clutch mounting cavity 204. Thus, the positioning hole 138 of the flange 132 can cooperate with the positioning pin 216 on the flange mounting surface 214 on the peripheral side of the clutch mounting cavity 204 to achieve rapid positioning and installation of the gear fixing block 130, thereby improving removal efficiency.

[0046] In some embodiments, optionally, as Figure 1 As shown, the jacking pad 120 is a jacking pad made of nylon, and the gear fixing pad 130 is a gear fixing pad made of polyurethane.

[0047] Specifically, by configuring the jacking pad 120 to be a nylon jacking pad and the gear fixing pad 130 to be a polyurethane gear fixing pad, the nylon jacking pad 120 cushions the ejection force and protects the gear shaft 210, while the polyurethane gear fixing pad 130 automatically engages the tooth gap of the gear 206 when the bolts tighten the flange 132, forming a multi-point engagement. This eliminates the elastic deformation caused by traditional manual pressing and provides a constant locking force to prevent the gear shaft 210 from moving.

[0048] According to the second aspect of this application, Figure 7 As shown, the embodiment of the present application further provides a method for replacing the front lip seal of the APU gear box. Using the tooling for removing the front lip seal of the APU gear box of the above embodiment, the method for replacing the front lip seal of the APU gear box includes:

[0049] Step 202: Remove the clutch cover and clutch from the gearbox to expose the flange mounting surface and gears.

[0050] Step 204 , fasten the flange of the gear fixing pad to the flange mounting surface with bolts, so that the boss passes through the clutch mounting cavity and presses against the gear;

[0051] Step 206: insert the first diameter section of the jacking pad into the center hole of the shaft head of the gear shaft;

[0052] Step 208, screwing the external threaded end of the puller barrel into the threaded hole of the cavity sealed by the front lip;

[0053] Step 210: Rotate and screw in the screw to push the second diameter section against the gear shaft until the front lip seal is ejected.

[0054] Step 212, replace the front lip seal.

[0055] Specifically, the method for replacing the front lip seal of an APU gearbox includes: removing the clutch cover and clutch from the gearbox to expose the flange mounting surface and gear; bolting the flange of the gear fixing pad to the flange mounting surface, with the boss extending through the clutch mounting cavity to press against the gear; inserting the first diameter section of the push-in pad into the center hole of the gear shaft; screwing the externally threaded end of the puller barrel into the threaded hole of the front lip seal cavity; rotating the screw to push the second diameter section against the gear shaft until the front lip seal is ejected; and replacing the front lip seal. The method for replacing the front lip seal of an APU gearbox provided in this application eliminates the risk of gear movement through the gear fixing pad, while the nylon push-in pad cushions the ejection force and protects the gear shaft. The dual tooling reduces the number of operators to one, shortening construction time and reducing the difficulty. There is no need to verify gear height, reducing process steps, and preventing human contact with high-temperature components. This fundamentally solves the problems of low efficiency, high operational risks, and unstable maintenance quality associated with traditional processes due to their reliance on manual intervention.

[0056] In some embodiments, optionally, after replacing the front lip seal, the method further includes: installing a retaining spring to fix the front lip seal.

[0057] Specifically, after replacing the front lip seal, the process also includes installing a retaining spring to fix the front lip seal.

[0058] In some embodiments, optionally, after replacing the front lip seal, the method further includes: removing the gear fixing gasket, and reinstalling the clutch cover and the clutch.

[0059] Specifically, after replacing the front lip seal, the gear fixing pad is removed and the clutch cover and clutch are reinstalled.

[0060] Specifically, the specific operation process for replacing the APU gearbox front lip seal is as follows:

[0061] 1. Prepare the puller tooling and corresponding tools;

[0062] 2. Remove the clutch cover, take out the clutch, and install the gear fixing pad on the gearbox clutch cover mounting flange. Use three bolts to install the gear fixing pad to the gearbox flange. At this time, the boss of the gear fixing pad has been pressed against the gear to prevent the gear from being pulled out by force.

[0063] 3. Use circlip pliers to remove the circlip located on the front lip sealing cavity;

[0064] 4. The diameter of one end of the jacking block is smaller than the inner diameter of the shaft head of the gear shaft. Inserting the jacking block onto the gear shaft can prevent the tool from falling off during operation. Screw the external thread end of the puller barrel into the threaded hole of the front lip sealing cavity, and rotate the screw until the front lip sealing cavity is ejected.

[0065] 5. Replace the new rubber ring and front lip seal, and install the retaining spring;

[0066] 6. Unscrew the three bolts, remove the gear fixing pad, install the clutch, and the replacement work is completed.

[0067] In the description of this application, the term "plurality" refers to two or more than two. Unless otherwise expressly defined, the orientation or positional relationship indicated by the terms "upper" and "lower" is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on this application. The terms "connection", "installation", "fixed", etc. should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0068] Throughout this specification, terms such as "one embodiment," "some embodiments," and "specific embodiments" mean that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0069] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A tool for removing the seal of the front lip of an APU gearbox, characterized in that: The gearbox is provided with a front lip seal operating hole and a clutch installation cavity which are perpendicular to each other. A gear and a front lip seal are provided inside the gearbox. The gear shaft of the gear is inserted into the cavity of the front lip seal. The puller tooling includes: A puller cylinder, wherein the outer wall of one end of the puller cylinder is provided with an external thread, and the inner wall of the other end is provided with an internal thread; A jacking pad, movably arranged in the inner cavity of the puller cylinder; A gear fixing pad, comprising a flange and a boss, wherein the boss extends along the axis of the flange; The screw is screwed in and movably connected with the internal thread on the inner wall of the puller barrel; Among them, when the front lip seal is removed, the flange plate is fixed to the flange mounting surface on the peripheral side of the clutch mounting cavity, the boss passes through the clutch mounting cavity and presses against the gear, the external threaded end of the puller cylinder is connected to the threaded hole on the front lip seal cavity through the front lip seal operating hole, one end of the jacking pad rests on the gear shaft, and the other end of the jacking pad abuts against the screw-in screw.

2. The APU gearbox front lip seal removal tool according to claim 1, characterized in that: The jacking pad is in the shape of a stepped cylinder and comprises a first diameter section and a second diameter section, wherein the first diameter section is coaxially connected to the second diameter section; When the front lip seal is removed, the first diameter section abuts against or is inserted into the end of the gear shaft, and the second diameter section abuts against the screw-in screw.

3. The tooling for removing the front lip seal of the APU gearbox according to claim 2, characterized in that: The outer diameter of the first diameter section is smaller than that of the second diameter section, the outer wall of the second diameter section is in clearance with the inner cavity of the puller barrel, and the height of the second diameter section is greater than the maximum stroke of the screw rod in the puller barrel.

4. The APU gearbox front lip seal removal tool according to claim 1, characterized in that: The height of the boss in the gear fixing pad is adapted to the distance from the gear to the flange mounting surface on the peripheral side of the clutch mounting cavity, and a supporting portion is provided at the end of the boss close to the gear, and the shape of the supporting portion is adapted to the shape of the gear surface.

5. The tooling for removing the front lip seal of the APU gearbox according to claim 1, characterized in that: The gear fixing pad is provided with a plurality of connection holes, and the plurality of connection holes are evenly distributed on the flange plate and are used for connecting and fixing with the flange mounting surface on the peripheral side of the clutch mounting cavity.

6. The tooling for removing the front lip seal of the APU gearbox according to claim 1, characterized in that: The gear fixing pad also includes a positioning hole, which is provided on the flange plate and is used to cooperate with a positioning pin on the flange mounting surface on the peripheral side of the clutch mounting cavity for positioning.

7. The tooling for removing the front lip seal of the APU gearbox according to claim 1, characterized in that: The jacking pad is a nylon jacking pad, and the gear fixing pad is a polyurethane gear fixing pad.

8. A method for replacing the front lip seal of an APU gearbox, characterized in that: Using the APU gearbox front lip seal removal tool as claimed in any one of claims 1 to 7, the replacement method comprises: Remove the clutch cover and clutch on the gearbox to expose the flange mounting surface and gear; Fix the flange of the gear fixing pad to the flange mounting surface with bolts, so that the boss passes through the clutch mounting cavity and presses against the gear; Inserting the first diameter section of the jacking pad into the center hole of the shaft head of the gear shaft; Screw the external threaded end of the puller barrel into the threaded hole of the cavity sealed by the front lip; Rotate the screw-in screw to push the second diameter section against the gear shaft until the front lip seal is ejected; Replace the front lip seal.

9. The method for replacing the front lip seal of an APU gearbox according to claim 8, characterized in that: After replacing the front lip seal, the method further includes: Install the retaining ring to secure the front lip seal.

10. The method for replacing the front lip seal of an APU gearbox according to claim 8, characterized in that: After replacing the front lip seal, the method further includes: Remove the gear fixing pad and reinstall the clutch cover and clutch.

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