An assembly device and method for an internal graphite bearing in an aircraft fuel pump.

Abstract

This invention provides an assembly device and method for an internal graphite bearing of an aircraft fuel pump, belonging to the field of aviation repair technology. The assembly device includes component one, component two, and a fixture. Component one includes a pressure rod one that fits against the surface of the graphite bearing, a positioning sleeve that positions and guides the pressure rod one and the bushing, and a support that cooperates with the pressure rod one to ensure coaxiality. Component one is used to install the first graphite bearing so that its groove forms a 30° angle with the line connecting the bushing groove. Component two includes a pressure rod two and a positioning support, which cooperate to install the second graphite bearing, ensuring that the groove angle of the two graphite bearings is maintained at 90°±10°. After the two graphite bearings are installed, they are clamped by the fixture and heat-treated to complete the assembly. This invention effectively ensures the installation requirements of the graphite bearing, thereby guaranteeing the assembly quality, greatly improving work efficiency, saving time and effort, and reducing economic losses while avoiding quality risks.

Description

Technical Field

[0001] This invention belongs to the field of aviation repair technology and relates to an assembly device and assembly method for an internal graphite bearing of an aircraft fuel pump. Background Technology

[0002] The fuel pump of a certain type of aircraft is a crucial accessory in the fuel system. Mounted on the engine transmission housing and driven by the engine, it pressurizes the fuel flowing into the collector and delivers it to the hydraulic turbine pump and jet pump, providing them with the power fuel for startup. During repairs, severe wear and chipping of the graphite bearings frequently occur, requiring disassembly and reassembly for replacement. Because the installation of graphite bearings has specific requirements, existing assembly methods cannot meet these requirements, affecting assembly quality. Therefore, a specialized assembly device is needed to complete the reassembly and restore the inherent reliability of the product.

[0003] The rationality of the assembly device and method for graphite bearings directly affects the product's service life and reliability. Inappropriate assembly may lead to malfunctions such as rotor rubbing and bearing seizure during operation. (See fuel pump drawings for assembly requirements.) Figure 4 The main body of the housing assembly is a disc, with a bushing installed at the center of the disc. On both sides of the disc, there are coaxial long columnar structures and short columnar structures respectively. The line connecting the center lines of the grooves of the two graphite bearings installed inside the bushing is kept at an angle of 30° relative to the line connecting the center lines of the two grooves on the circumference of the bushing. The angle between the groove F of the first graphite bearing and the groove E of the second graphite bearing is kept at (90±10)°.

[0004] Currently, the assembly of graphite bearings inside fuel pumps requires first measuring the installation angle with a ruler, then drawing the installation line with a marker, visually aligning the graphite bearing groove with the drawn line, and finally using a press to install the bearing into place. This assembly method cannot accurately guarantee the required installation direction of the graphite bearing, and it cannot ensure that the graphite bearing is pressed vertically during installation, easily causing damage to the outer wall of the bearing. In severe cases, this can lead to the bearing breaking, resulting in economic losses. Damage to the outer wall of the graphite bearing will affect the performance of the fuel pump, thus posing a quality risk and a potential threat to flight safety. Summary of the Invention

[0005] This invention provides an assembly device and method for an internal graphite bearing in an aircraft fuel pump. The method is fast and efficient, effectively ensuring the installation requirements of the graphite bearing during assembly, thereby guaranteeing assembly quality. Using this invention will greatly improve work efficiency, saving time and effort, reducing economic losses, and avoiding quality risks.

[0006] The specific technical solution of the present invention is as follows:

[0007] An assembly device for an internal graphite bearing of an aircraft fuel pump, the assembly device comprising component one, component two, and a fixture.

[0008] The first component includes a pressure rod 1, a positioning ring 2, and a support 3. The pressure rod 1 is a cylinder with an outer diameter the same as that of the graphite bearing. Four prisms are evenly distributed along the circumference of the cylinder's sidewall. An annular protrusion is formed at the center of the cylinder's bottom surface. The outer circle of the annular protrusion is tightly fitted with the inner hole of the graphite bearing. The bottom surface of the cylinder has strip-shaped protrusions that conform to the surface profile of the graphite bearing, allowing the graphite bearing to fit against the bottom surface of the pressure rod 1 for positioning. At the same time, the pressure rod 1 is used to press the graphite bearing into the bushing. 9. The positioning ring 2 is annular, and its inner diameter matches the outer diameter of the graphite bearing and the pressure rod 1 to achieve a sliding fit. Four guide grooves are evenly distributed along the circumference of the inner wall of the positioning ring 2, which slide in fit with the prisms on the side wall of the pressure rod 1 to achieve a positioning fit. The outer diameter of the positioning ring 2 is consistent with the outer diameter of the inner bushing 9 of the housing assembly 8. Two protrusions are formed on the circumference of its bottom surface to engage with two grooves on the circumference of the bushing 9 for positioning. The pressure rod 1 and the positioning ring 2 are positioned together. After assembly, the line connecting the flat protrusions on the bottom of the pressure rod 1 forms a 30° angle with the line connecting the two protrusions on the bottom of the positioning ring 2, ensuring that the angle between the line connecting the centerline of the groove on the graphite bearing and the line connecting the centerlines of the two grooves on the circumference of the bushing 9 remains at 30°. The support 3 is a three-step columnar structure with its outer diameter increasing from top to bottom. The outer diameter of the middle section of the support 3 matches the inner diameter of the long columnar structure on one side of the housing assembly 8. The housing assembly 8 is fitted onto the middle section of the support 3 and placed on the lower end of the support 3. The upper section of the support 3 serves as a guide. The column, whose outer diameter mates with the inner hole of the annular protrusion at the center of the bottom surface of the pressure rod 1, is used to guide the graphite bearing and the bushing 9 to be coaxial. In use, the long columnar structure of the housing assembly 8 is placed on the support 3 with one side facing down. The upper guide column passes through the inner hole of the bushing 9. The positioning ring 2 is positioned on the bushing 9. After the graphite bearing is attached to the bottom surface of the pressure rod 1, it is guided through the prism and the guide groove to pass into the positioning ring 2. The annular protrusion of the pressure rod 1 and the guide column of the support 3 are engaged for guidance.

[0009] The second component includes a pressure rod 4 and a positioning support 5. The pressure rod 4 is basically the same in structure as the pressure rod 1, except that the cylindrical sidewall of the pressure rod 4 does not have prisms, and the inner hole of the annular protrusion on the bottom surface is a square hole. The pressure rod 4 is used to fit against another graphite bearing to achieve positioning and press into the bushing 9. The positioning support 5 is cylindrical, and its outer diameter is clearance-fitted with the inner hole of a short cylinder on one side of the housing assembly 8. Two protrusions are arranged opposite each other along the diameter on its upper surface to cooperate with two grooves on the bushing 9 to achieve positioning. The center of the upper surface of the positioning support 5 is coaxially square. The guide post is used to pass through the inner hole of the housing assembly 8 and engage with the square hole of the annular protrusion on the bottom surface of the pressure rod 4 to position the other graphite bearing relative to the bushing 9, so that the groove angle of the two graphite bearings is maintained at 90°±10°. In use, the short cylindrical structure of the housing assembly 8 is inserted downward into the positioning support 5, so that the two protrusions on the positioning support 5 engage with the two grooves of the bushing 9 for positioning. After the graphite bearing and the pressure rod 4 are attached, they are placed into the long cylindrical structure of the housing assembly 8, and the square hole on the bottom surface of the pressure rod 4 engages with the square positioning post of the positioning support 5.

[0010] The clamp includes fastening component 6 and fastening component 7, both of which are cylindrical structures. They are respectively placed into the inner holes of the cylindrical structures on both sides of the housing assembly 8 and fit against the bushing 9 and the graphite bearing. The center of the opposite end faces of both components is made of a circular protrusion, the outer diameter of which matches the inner hole of the graphite bearing. Both fastening component 6 and fastening component 7 are made of through holes along their centers for screws to pass through. The tail of the screw is screwed into a nut to clamp the two graphite bearings.

[0011] Furthermore, the pressure rod 1 and pressure rod 4 are made of relatively soft materials such as polytetrafluoroethylene to avoid damage when pressing the graphite bearing into the bushing 9.

[0012] A method for assembling a graphite bearing inside an aircraft fuel pump, based on the aforementioned assembly device, employs a thermal assembly method due to the different coefficients of thermal expansion between the graphite bearing and the fuel pump housing. The assembly method includes the following steps:

[0013] Step 1, Assemble the first graphite bearing:

[0014] Step 1.1: Place the shell assembly 8 in an electric thermostatic drying oven and heat it until the temperature reaches 170℃±3℃, then keep it at that temperature for 60±5 minutes.

[0015] Step 1.2: Take out the housing assembly 8, and place the long columnar structure of the housing assembly 8 downwards onto the support 3. Position the positioning ring 2 on the bushing 9, and align the protrusion of the positioning ring 2 with the groove of the bushing 9. Align the groove of the first graphite bearing with the protrusion on the bottom surface of the pressure rod 1, so that the two fit together. Secure the inner hole of the first graphite bearing to the outer circle of the annular protrusion of the pressure rod 1. Insert both into the positioning ring 2. The prism on the pressure rod 1 and the guide groove on the positioning ring 2 achieve guidance and positioning. At the same time, the inner hole of the annular protrusion of the pressure rod 1 and the guide post of the support 3 cooperate to ensure coaxiality.

[0016] Step 1.3: Press the first graphite bearing into bushing 9 using a press to complete the assembly. Component 1 ensures that the angle between the groove of the first graphite bearing and the groove of bushing 9 remains at 30°.

[0017] Step 2, the assembly method for assembling the second graphite bearing device 2 is as follows:

[0018] Step 2.1: After completing the assembly of the first graphite bearing, place the housing assembly 8 together with the first graphite bearing in the electric heating constant temperature drying oven again for heating. After the temperature reaches 170℃±3℃, keep it at that temperature for 60±5 minutes.

[0019] Step 2.2 Take out the housing assembly 8, insert the long cylindrical side of the housing assembly 8 upward into the positioning support 5, align the two protrusions on the positioning support 5 with the two grooves of the bushing 9, align the groove of the second graphite bearing with the protrusion on the bottom surface of the pressure rod 4, so that the two fit together, and fasten the inner hole of the second graphite bearing with the outer circle of the annular protrusion of the pressure rod 4. Put the two together into the long cylindrical structure of the housing assembly 8, and align the square hole on the bottom surface of the pressure rod 4 with the square positioning post of the positioning support 5.

[0020] Step 2.3: Use a press to press the second graphite bearing into the other side of bushing 9 to complete the assembly. Component 2 ensures that the groove angle of the two graphite bearings remains at 90°±10°.

[0021] Step 3: Place the sides of fastening component 6 and fastening component 7 with the circular protrusions facing each other, and align them with the inner holes of the two graphite bearings from both sides of the assembled housing assembly 8. Insert screws and tighten nuts to complete the clamping. Place them together in an electric heating constant temperature drying oven and heat to 100℃±3℃ for 2 hours. Remove them from the heating oven and remove the clamps. Store them at ambient temperature for no less than 16 hours.

[0022] The beneficial effects of this invention are as follows: Due to the special structure of a certain type of aircraft fuel pump, existing technologies cannot guarantee the installation requirements of graphite bearings, and cannot ensure that the graphite bearings are pressed vertically downwards during installation, which can easily cause damage to the outer wall of the graphite bearings, and in severe cases, lead to the graphite bearings breaking, affecting flight safety. The device of this invention ensures that the two graphite bearings meet the technical requirements after assembly.

[0023] The method of the present invention involves placing a housing assembly with a bushing in a heating chamber, maintaining the temperature at (170±3)℃ for (60±5) min, removing the housing assembly, and assembling the graphite bearing using an assembly device. This forms a graphite bearing assembly method that ensures the reliability of the fuel pump after the graphite bearing is assembled. Attached Figure Description

[0024] Figure 1 This is a structural diagram of component one;

[0025] Figure 2 This is the structural diagram of component two;

[0026] Figure 3 This is a diagram of the fixture structure;

[0027] Figure 4 The diagram shows the installation direction of the graphite bearing, where (a) is a schematic diagram of the installation of the graphite bearing groove relative to the bushing groove, and (b) and (c) are schematic diagrams of the relative angles of the installation of the two graphite bearings.

[0028] Figure 5 This is a schematic diagram of the first bearing assembly;

[0029] Figure 6 This is a schematic diagram of the second bearing assembly;

[0030] Figure 7 This is a schematic diagram of the fixture assembly.

[0031] Figure 8 This is a schematic diagram of component one.

[0032] Figure 9 This is a schematic diagram of component two.

[0033] Figure 10 This is a schematic diagram of the fixture assembly.

[0034] In the diagram: 1. Pressure bar one; 2. Positioning ring sleeve; 3. Support; 4. Pressure bar two; 5. Positioning support; 6. Fastening assembly one; 7. Fastening assembly two; 8. Housing assembly; 9. Bushing. Detailed Implementation

[0035] The technical solution of the present invention will now be clearly and completely described. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. All other embodiments derived by those skilled in the art based on the embodiments of the present invention through modifications or adjustments are within the protection scope of the present invention.

[0036] An assembly device for an internal graphite bearing of an aircraft fuel pump, the assembly device comprising component one, component two, and a fixture.

[0037] The first component includes a pressure rod 1, a positioning ring 2, and a support 3, as shown below. Figure 1 and Figure 8 As shown; the pressure rod 1 is a cylinder made of polytetrafluoroethylene (PTFE), with an outer diameter the same as that of the first graphite bearing. Four prisms are evenly distributed along the circumference of the cylinder's sidewall. A ring-shaped protrusion is formed at the center of the cylinder's bottom surface, and its outer circle is tightly fitted to the inner hole of the first graphite bearing. A strip-shaped protrusion is provided on the bottom surface of the cylinder, corresponding to the F-shaped groove on the surface of the first graphite bearing, allowing the first graphite bearing to fit against the bottom surface of the pressure rod 1 for positioning. Simultaneously, the pressure rod 1 also serves to hold the first graphite bearing... The positioning ring 2 is pressed into the bushing 9; its inner diameter matches the outer diameter of the first graphite bearing and the pressure rod 1, achieving a sliding fit. The inner wall of the positioning ring 2 has four guide grooves evenly distributed along its circumference, which slide into contact with the prisms on the side wall of the pressure rod 1, achieving a positioning fit. The outer diameter of the positioning ring 2 is consistent with the outer diameter of the bushing 9 inside the housing assembly 8. Its bottom circumference has two protrusions that engage with two grooves on the circumference of the bushing 9 to achieve positioning. The pressure rod 1 is also positioned by the positioning ring 2. After assembly, the line connecting the flat protrusions on the bottom of the pressure rod 1 forms a 30° angle with the line connecting the two protrusions on the bottom of the positioning ring 2, ensuring that the angle between the line connecting the centerline of the groove F on the first graphite bearing and the line connecting the centers of the two grooves on the circumference of the bushing 9 remains at 30°. The support 3 is a three-step columnar structure with its outer diameter increasing from top to bottom. The outer diameter of the middle section of the support 3 matches the inner diameter of the long columnar structure on one side of the housing assembly 8. The housing assembly 8 is fitted onto the middle section of the support 3 and placed on the lower end of the support 3. The upper section of the support 3 is a guide post. Its outer diameter matches the inner hole of the annular protrusion at the center of the bottom surface of the pressure rod 1, which is used to guide the first graphite bearing to be coaxial with the bushing 9. In use, the long columnar structure of the housing assembly 8 is placed on the support 3 with one side facing down. The upper guide column passes through the inner hole of the bushing 9. The positioning ring 2 is positioned on the bushing 9. After the first graphite bearing is attached to the bottom surface of the pressure rod 1, it is guided through the prism and the guide groove to pass into the positioning ring 2. The annular protrusion of the pressure rod 1 matches the guide column of the support 3 for guidance.

[0038] The second component includes a pressure rod 4 and a positioning support 5, such as... Figure 2 and Figure 9As shown; the pressure rod 4 is made of polytetrafluoroethylene and has a structure basically the same as the pressure rod 1, except that the cylindrical sidewall of the pressure rod 4 does not have prisms, and the inner hole of the annular protrusion on the bottom surface is a square hole. The pressure rod 4 is used to fit the second graphite bearing to achieve positioning and press into the bushing 9; the positioning support 5 is cylindrical, and its outer diameter is clearance-fitted with the inner hole of the short cylinder on one side of the housing assembly 8. Two protrusions are provided on its upper surface along the diameter to cooperate with the two grooves on the bushing 9 to achieve positioning. A coaxial square guide is made at the center of the upper surface of the positioning support 5. The guide post is used to pass through the inner hole of the housing assembly 8 and mate with the square hole of the annular protrusion on the bottom surface of the pressure rod 4 to position the second graphite bearing relative to the bushing 9, so that the groove angle of the two graphite bearings is maintained at 90°±10°. In use, the short cylindrical structure of the housing assembly 8 is inserted downward into the positioning support 5, so that the two protrusions on the positioning support 5 mate with the two grooves of the bushing 9 for positioning. After the graphite bearing and the pressure rod 4 are attached, they are placed into the long cylindrical structure of the housing assembly 8, and the square hole on the bottom surface of the pressure rod 4 mates with the square positioning post of the positioning support 5.

[0039] The clamp includes fastening component 6 and fastening component 7, such as... Figure 3 and Figure 10 As shown, both are cylindrical structures, which are placed in the inner holes of the cylindrical structures on both sides of the housing assembly 8 and fit with the bushing 9 and the graphite bearing. The center of the opposite end faces of both have a circular protrusion, and the outer diameter of the circular protrusion matches the inner hole of the graphite bearing. Fastening component 1 6 and fastening component 2 7 both have through holes along the center for screws to pass through. The tail of the screw is screwed into a nut to clamp the two graphite bearings.

[0040] A method for assembling a graphite bearing inside an aircraft fuel pump, based on the aforementioned assembly device, employs a thermal assembly method due to the different coefficients of thermal expansion between the graphite bearing and the fuel pump housing. The assembly method includes the following steps:

[0041] Step 1, assemble the first graphite bearing, such as Figure 5 As shown:

[0042] Step 1.1: Place the shell assembly 8 in an electric thermostatic drying oven and heat it until the temperature reaches 170℃±3℃, then keep it at that temperature for 60±5 minutes.

[0043] Step 1.2: Take out the housing assembly 8, and place the long columnar structure of the housing assembly 8 downwards onto the support 3. Position the positioning ring 2 on the bushing 9, and align the protrusion of the positioning ring 2 with the groove of the bushing 9. Align the groove F of the first graphite bearing with the protrusion on the bottom surface of the pressure rod 1, so that the two fit together. Secure the inner hole of the first graphite bearing to the outer circle of the annular protrusion of the pressure rod 1. Insert both into the positioning ring 2. The prism on the pressure rod 1 and the guide groove on the positioning ring 2 are used for guidance and positioning. At the same time, the inner hole of the annular protrusion of the pressure rod 1 and the guide post of the support 3 are matched to ensure coaxiality.

[0044] Step 1.3: Press the first graphite bearing into bushing 9 using a press to complete the assembly. Component 1 ensures that the angle between the groove F of the first graphite bearing and the groove of bushing 9 remains at 30°.

[0045] Step 2, the assembly method for assembling the second graphite bearing device 2 is as follows, such as... Figure 6 As shown:

[0046] Step 2.1: After completing the assembly of the first graphite bearing, place the housing assembly 8 together with the first graphite bearing in the electric heating constant temperature drying oven again for heating. After the temperature reaches 170℃±3℃, keep it at that temperature for 60±5 minutes.

[0047] Step 2.2 Take out the housing assembly 8, insert the long cylindrical side of the housing assembly 8 upward into the positioning support 5, align the two protrusions on the positioning support 5 with the two grooves of the bushing 9, align the groove E of the second graphite bearing with the protrusion on the bottom surface of the pressure rod 4, so that the two fit together, and fasten the inner hole of the second graphite bearing with the outer circle of the annular protrusion of the pressure rod 4. Put the two together into the long cylindrical structure of the housing assembly 8, and align the square hole on the bottom surface of the pressure rod 4 with the square positioning post of the positioning support 5.

[0048] Step 2.3: Use a press to press the second graphite bearing into the other side of bushing 9 to complete the assembly. Component 2 ensures that the groove angle of the two graphite bearings remains at 90°±10°.

[0049] Step 3, as follows Figure 7 As shown, fastening components 6 and 7 with their circular protrusions facing each other are fitted with the inner holes of the two graphite bearings from both sides of the assembled housing assembly 8. Screws are then inserted and nuts are tightened to complete the clamping. The assembly is then placed in an electric heating constant temperature drying oven and heated to 100℃±3℃ for 2 hours. The assembly is then removed from the heating oven and the clamps are removed. The assembly is then stored at ambient temperature for no less than 16 hours.

[0050] The above embodiments are merely illustrative of the implementation methods of the present invention, but should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the protection scope of the present invention.

Claims

1. An assembly device for an internal graphite bearing of an aircraft fuel pump, characterized in that, The assembly device includes component one, component two, and a fixture; The first component includes a pressure rod (1), a positioning ring (2), and a support (3). The pressure rod (1) is a cylinder with the same outer diameter as the graphite bearing. Its bottom surface is designed to fit the graphite bearing surface to achieve positioning and fit. It is used to press the graphite bearing into the bushing (9). The center of the bottom surface of the cylinder of the pressure rod (1) has an annular protrusion. The outer circle of the annular protrusion is tightly fitted with the inner hole of the graphite bearing. The positioning ring (2) is annular. Its inner diameter matches and positions the outer diameter of the pressure rod (1). The outer diameter of the positioning ring (2) is fitted with the inner bushing (9) of the housing assembly (8). The outer diameter is consistent and it is positioned and matched with the bushing (9). After the pressure rod (1) and the positioning ring (2) are positioned and combined, the angle between the line connecting the center line of the groove on the graphite bearing and the line connecting the center of the two grooves on the circumference of the bushing (9) is maintained at 30°. The support (3) is a three-step columnar structure, and the outer diameter increases from top to bottom. The outer diameter of the middle section of the support (3) matches the inner diameter of the long columnar structure on one side of the housing assembly (8). The upper section of the support (3) is a guide column, and its outer diameter matches the inner hole of the annular protrusion at the center of the bottom surface of the pressure rod (1) to realize the coaxiality of the graphite bearing and the bushing (9). The second component includes a pressure rod (4) and a positioning support (5). The pressure rod (4) is a cylinder with the same outer diameter as the graphite bearing. The bottom surface is set according to the surface of the graphite bearing to achieve positioning and fitting of the two. It is used to press another graphite bearing into the bushing (9). The center of the bottom surface of the cylinder of the pressure rod (4) has an annular protrusion. The outer circle of the annular protrusion is tightly fitted with the inner hole of the graphite bearing. The inner hole of the annular protrusion is a square hole. The positioning support (5) is a cylinder with a clearance fit between its outer diameter and the inner hole of the short cylinder on one side of the housing assembly (8). Its upper surface fits with the bushing (9) to achieve positioning. The center of the upper surface of the positioning support (5) has a square guide post, which is used to pass through the inner hole of the housing assembly (8) and fit with the square hole of the annular protrusion on the bottom surface of the pressure rod (4) to position the other graphite bearing relative to the bushing (9) and achieve the groove angle of the two graphite bearings to be maintained at 90°±10°. The clamp includes fastening component one (6) and fastening component two (7), both of which are cylindrical structures and are respectively placed in the inner holes of the cylindrical structures on both sides of the housing assembly (8). The center of the opposite end faces of the two components is made of a circular protrusion that fits into the inner hole of the graphite bearing. Both components are made of a through hole along the center for the screw to pass through the mating nut to achieve clamping. The cylinder sidewall of the pressure rod (1) has four prisms evenly distributed around the circumference, and the inner wall of the positioning ring (2) has four guide grooves evenly distributed around the circumference, which slide with the prisms on the sidewall of the pressure rod (1) to achieve positioning and cooperation between the two. The bottom surfaces of the pressure rod one (1) and pressure rod two (4) are provided with strip-shaped protrusions that match the grooves on the surface of the graphite bearing, so that the graphite bearing can be positioned by fitting with the bottom surface of the pressure rod one (1) or pressure rod two (4).

2. The assembly device for the internal graphite bearing of an aircraft fuel pump according to claim 1, characterized in that, The positioning ring (2) has two protrusions on its bottom circumference, which are used to cooperate with the two grooves on the circumference of the bushing (9) to achieve positioning.

3. The assembly device for the internal graphite bearing of an aircraft fuel pump according to claim 1, characterized in that, The positioning support (5) has two protrusions on its upper surface that are opposite each other along the diameter, which are used to cooperate with the two grooves on the bushing (9) to achieve positioning.

4. The assembly device for the internal graphite bearing of an aircraft fuel pump according to claim 1, characterized in that, The pressure bar one (1) and pressure bar two (4) are made of polytetrafluoroethylene.

5. A method for assembling a graphite bearing inside an aircraft fuel pump, implemented based on the assembly device described in any one of claims 1-4, characterized in that, The assembly method includes the following steps: Step 1, Assemble the first graphite bearing: Step 1.1: Place the shell assembly (8) in an electric heating constant temperature drying oven and heat it until the temperature reaches 170℃±3℃, then keep it at that temperature for 60±5 minutes. Step 1.2, take out the housing assembly (8), put the long columnar structure of the housing assembly (8) downward on the support (3), and position the positioning ring (2) on the bushing (9). The positioning ring (2) and the bushing (9) are aligned. Align the groove of the first graphite bearing with the pressure rod (1). Tighten the inner hole of the first graphite bearing with the outer circle of the annular protrusion of the pressure rod (1). The two are inserted into the positioning ring (2) and guided and positioned. At the same time, the inner hole of the annular protrusion of the pressure rod (1) is aligned with the guide post of the support (3) to ensure coaxiality. Step 1.3: Press the first graphite bearing into the bushing (9) using a press to complete the assembly work; Step 2, assembling the second graphite bearing: The assembly method is as follows: Step 2.1 After completing the assembly of the first graphite bearing, place the housing assembly (8) together with the first graphite bearing in the electric heating constant temperature drying oven again for heating. After the temperature reaches 170℃±3℃, keep it at that temperature for 60±5min. Step 2.2 Take out the housing assembly (8), insert the long cylindrical side of the housing assembly (8) upward into the positioning support (5), align the positioning support (5) with the bushing (9), align the second graphite bearing with the pressure rod (4), and make them fit together. The inner hole of the second graphite bearing is fastened to the outer circle of the annular protrusion of the pressure rod (4). The two are placed together into the long cylindrical structure of the housing assembly (8), and the square hole on the bottom surface of the pressure rod (4) is matched with the square positioning post of the positioning support (5). Step 2.3: Press the second graphite bearing into the other side of the bushing (9) using a press to complete the assembly work; Step 3: Place the sides of fastening component 1 (6) and fastening component 2 (7) with the circular protrusions facing each other, and align them with the inner holes of the two graphite bearings from both sides of the assembled housing assembly (8). Insert screws and tighten nuts to complete the clamping. Place them together in an electric heating constant temperature drying oven and heat them to 100℃±3℃ for 2 hours. Remove them from the heating oven and remove the clamps. Store them at ambient temperature for no less than 16 hours.

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