A method for replacing a positioning pin of a deep cavity narrow part of a machine case

Abstract

The application discloses a kind of machine case deep cavity narrow site positioning pin replacement method, including the following steps: obtaining the interference amount of positioning pin and corresponding installation hole on machine case;According to the size of the interference amount obtained, the corresponding processing mode is selected to pretreat the positioning pin, reduce the interference amount of positioning pin and corresponding installation hole on machine case or ensure that the positioning pin removal device and the positioning pin have a friction force matched with the interference amount, then the positioning pin is clamped and taken out by the positioning pin removal device, and the pretreatment includes heat treatment or machining treatment.The application increases the friction coefficient when the positioning pin is pulled out, improves the success rate of pulling out the positioning pin, reduces the difficulty of pulling out the positioning pin, and at the same time solves the problem that the operation space of the machine case deep cavity is small and the positioning pin cannot be clamped.The time for taking out the positioning pin in the narrow part of the machine case deep cavity is shortened from 1h to 5min, greatly shortening the repair cycle of the part.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aero-engines, in particular, to a method for replacing a positioning pin at a deep-cavity narrow part of a casing. BACKGROUND

[0002] When repairing an air intake casing of a certain type of engine, the 4mm positioning pin needs to be replaced with a 4.75mm positioning pin. The base material is cast aluminum, the pin is 1Gr18Ni9Ti, and the interference amount is required to be 0.011-0.031mm.

[0003] Due to the narrowness of the casing inner cavity where the positioning pin is located and the distance of 133mm from the casing mounting surface, the interference range is only Φ7, and the positioning pin cannot be removed using general pliers and other tools, so the currently used processing methods mainly include two kinds:

[0004] (1) Processing scheme: fine boring - bench work - flushing - inspection

[0005] Among them, the positioning pin removal method is to directly use a 3.8 drill bit to remove the positioning pin, and then bore the hole diameter to the size.

[0006] The existing problems are: the tool can only be selected as a 3.8 drill bit, but the tool needs to be within a length of 145 with a diameter of <Φ8, so the tool strength is low, the processing material is hard, and the drill bit is easy to break during processing. After breaking, it needs to be taken out by electric spark, which takes a long time.

[0007] (2) Processing scheme: electric spark - bench work - fine boring - bench work - flushing - inspection

[0008] Among them, the positioning pin removal method is to use electric spark to process a 3.8mm hole on the pin, and then the pin is pulled out by the bench worker.

[0009] The existing problems are: the electric spark processing time is long (more than 1h for a single pin), the processing efficiency is low, the equipment task is full, the part waiting time is long, and it cannot meet the node requirements of the repaired machine. SUMMARY

[0010] The present application provides a method for replacing a positioning pin at a deep-cavity narrow part of a casing to solve the technical problems of long time, low efficiency and easy breaking of the drill bit in the existing positioning pin removal method.

[0011] The present application is realized by the following scheme:

[0012] A method for replacing a positioning pin at a deep-cavity narrow part of a casing, comprising the steps of:

[0013] Obtaining the interference amount of the positioning pin and the corresponding mounting hole of the casing;

[0014] According to the size of the obtained interference amount, the corresponding processing mode is selected to pretreat the positioning pin, and then the positioning pin is clamped and taken out by the positioning pin removing device, and the pretreatment includes heat treatment or machining treatment.

[0015] Further, the positioning pin removing device comprises a handle, a fixing nut, a sleeve, an elastic chuck, and an extension rod, the fixing nut is threadedly connected with a threaded segment arranged on the extension rod, one end of the extension rod is detachably connected with the handle, the other end of the extension rod is detachably connected with the elastic chuck, the sleeve has a diameter less than or equal to the interference diameter of the positioning pin and a length greater than the depth from the positioning pin to the end face of the casing, and the sleeve is movably sleeved on the outer peripheral wall of the extension rod in the axial direction, an inner tapered surface matched with the outer tapered surface of the elastic chuck is arranged in the inner hole of the end of the sleeve away from the handle, and the end of the sleeve towards the handle abuts against the fixing nut, the inner hole wall of the elastic chuck is provided with a toothed knurl, and the inner hole of the elastic chuck is also provided with a first clamping groove at a distance from the opening end surface thereof.

[0016] Further, the cross section of the toothed knurl is triangular.

[0017] Further, the hardness of the inner hole wall of the elastic chuck is greater than the hardness of the positioning pin.

[0018] Further, the interference amount between the positioning pin and the corresponding mounting hole on the casing is obtained by referring to the design data of the positioning pin and the corresponding mounting hole on the casing.

[0019] Further, after the positioning pin is pretreated according to the size of the obtained interference amount, the positioning pin is clamped and taken out by the positioning pin removing device, and the pretreatment includes heat treatment or machining treatment.

[0020] Further, after the positioning pin is pretreated according to the size of the obtained interference amount, the positioning pin is clamped and taken out by the positioning pin removing device, and the pretreatment includes heat treatment or machining treatment.

[0021] When the interference amount is 0.01-0.015, the casing and the positioning pin are first subjected to heat treatment to make the positioning hole and the positioning pin produce different expansion amounts to reduce the interference amount.

[0022] Then, the elastic chuck of the positioning pin removing device is sleeved on the positioning pin extension part, and the fixing nut is tightened using a wrench to make the sleeve move downward and press the elastic chuck to clamp the positioning pin.

[0023] Finally, the positioning pin is pulled out by applying an upward pulling force to the handle.

[0024] Further, during the heat treatment, the target temperature after heating is determined by the following steps:

[0025] The diameter expansion amount of the casing is △d机匣 = a 机匣 *d0*(t1-t0), the diameter expansion of the positioning pin is △d 定位销 = a 定位销 *d0*(t1-t0), wherein a 机匣 and a 定位孔 are the expansion coefficients of the housing and the positioning pin respectively, d0 is the initial diameter, t1 is the target temperature after heating, and t0 is the initial temperature;

[0026] When the diameter expansion of the housing and the diameter expansion of the positioning pin are calculated so that the interference between the positioning hole and the positioning pin is reduced by half after the target temperature t1 after heating, the current target temperature t1 after heating is taken as the final heating temperature.

[0027] Further, the heating rate during the heating treatment is 5-6℃ / min, and the target temperature t1 after heating is ≤200℃.

[0028] Further, the positioning pin is pretreated according to the size of the obtained interference, and the positioning pin is clamped and taken out by the positioning pin removing device, specifically including the steps of:

[0029] When the interference is 0.016-0.025, the positioning pin extending part is sleeved by the positioning pin removing device, and then the fixed nut is tightened step by step using a wrench to clamp the positioning pin by the elastic chuck, the positioning pin removing device is rotated each time the fixed nut is tightened, and the process is repeated multiple times until the positioning pin removing device cannot be rotated, so that the final tooth-shaped knurl forms multiple layers of triangular grooves on the cylindrical surface of the positioning pin.

[0030] Finally, the positioning pin is pulled out by applying an upward pulling force to the handle.

[0031] Further, the positioning pin is pretreated according to the size of the obtained interference, and the positioning pin is clamped and taken out by the positioning pin removing device, specifically including the steps of:

[0032] When the interference is above 0.025, a second clamping groove is machined on the outer peripheral wall of the positioning pin at a distance below the exposed upper end surface of the positioning pin;

[0033] After the elastic chuck of the positioning pin removing device is sleeved on the positioning pin, the fixed nut is tightened, the sleeve moves downward to press the elastic chuck to clamp the positioning pin, and the part of the positioning pin above the second clamping groove is embedded into the first clamping groove to form a clamping position.

[0034] Finally, the positioning pin is pulled out by applying an upward pulling force to the handle.

[0035] Compared with the prior art, the present application has the following beneficial effects:

[0036] The application provides a casing deep cavity narrow part positioning pin replacement method, which comprises the following steps: obtaining the interference amount of the positioning pin and the corresponding mounting hole on the casing; according to the size of the obtained interference amount, selecting a corresponding processing mode to pretreat the positioning pin so that the interference amount is reduced or the friction force between the positioning pin removing device and the positioning pin is matched with the interference amount, and then the positioning pin is clamped and taken out by the positioning pin removing device, wherein the pretreatment comprises heat treatment or machining treatment.

[0037] The casing deep cavity narrow part positioning pin replacement method of the application is aimed at the different interference amounts of the positioning pin and the corresponding mounting hole on the casing, selects a corresponding processing mode such as heat treatment or machining treatment to pretreat the positioning pin, and then clamps and takes out the positioning pin by the positioning pin removing device after reducing the interference amount of the positioning pin and the corresponding mounting hole on the casing or ensuring that the friction force between the positioning pin removing device and the positioning pin is matched with the interference amount, thereby increasing the friction coefficient when the positioning pin is pulled out, improving the success rate of pulling out the positioning pin, reducing the difficulty of pulling out the positioning pin, solving the problem that the operation space of the casing deep cavity is small and the positioning pin cannot be clamped, and finally shortening the positioning pin taking-out time of the casing deep cavity narrow part from 1h to 5min, greatly shortening the repair cycle of the part.

[0038] In addition to the objects, features and advantages described above, the application has other objects, features and advantages. The application will be further described below with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0039] The drawings that form a part of this application are intended to provide a further understanding of the application, and the illustrative embodiments of the application and its description serve to explain the application without imposing undue limitation on the application.

[0040] Figure 1 The casing deep cavity narrow part positioning pin replacement method flowchart of the preferred embodiment of the application.

[0041] Figure 2 The positioning pin removing device structure schematic diagram of the preferred embodiment of the application.

[0042] Figure 3 The elastic chuck structure schematic diagram of the preferred embodiment of the application.

[0043] Figure 4 The positioning pin clamping groove stress schematic diagram of the preferred embodiment of the application.

[0044] Figure 5 The positioning pin grinding schematic diagram of the preferred embodiment of the application.

[0045] Figure 6 The positioning pin and elastic chuck assembly schematic diagram of the preferred embodiment of the application.

[0046] In the figure: 1, handle; 2, fixing nut; 3, sleeve; 4, elastic chuck; 41, knurled pattern; 42, first clamping groove; 5, triangular groove; 6, second clamping groove; 7, extension rod; 8, clamping position; 9, positioning pin. DETAILED DESCRIPTION

[0047] The embodiments of the present application are described in detail below with reference to the accompanying drawings, but the present application can be implemented in various different ways as defined and covered by the following.

[0048] As shown in the preferred embodiment of the present application provides a machine case deep cavity narrow site positioning pin replacement method, comprising the steps of: Figure 1 S1, get the interference amount of the positioning pin and the corresponding installation hole on the machine case;

[0049] S2, according to the size of the interference amount, select the corresponding processing method to pretreat the positioning pin, and then take out the positioning pin through the positioning pin removal device, the pretreatment includes heat treatment or machining treatment.

[0050] The embodiment provides a machine case deep cavity narrow site positioning pin replacement method, the machine case deep cavity narrow site positioning pin replacement method comprises the steps that the interference amount of the positioning pin and the corresponding installation hole on the machine case is obtained; according to the size of the interference amount, the corresponding processing method is selected to pretreat the positioning pin to reduce the interference amount or to make the positioning pin removal device and the positioning pin have a friction force matched with the interference amount, and then the positioning pin is clamped and taken out through the positioning pin removal device, and the pretreatment includes heat treatment or machining treatment.

[0051] The machine case deep cavity narrow site positioning pin replacement method of the embodiment is aimed at the different interference amounts of the positioning pin and the corresponding installation hole on the machine case, selects the corresponding processing method such as heat treatment or machining treatment to pretreat the positioning pin, then reduces the interference amount of the positioning pin and the corresponding installation hole on the machine case or ensures that the positioning pin removal device and the positioning pin have a friction force matched with the interference amount, and then the positioning pin is clamped and taken out through the positioning pin removal device, increases the friction coefficient when the positioning pin is pulled out, improves the success rate of pulling out the positioning pin, reduces the difficulty of pulling out the positioning pin, simultaneously solves the problem that the operation space of the machine case deep cavity is small and the positioning pin cannot be clamped, finally shortens the positioning pin taking-out time of the machine case deep cavity narrow site from 1h to 5min, greatly shortens the repair cycle of the part.

[0052]

[0053] ​Specifically, the positioning pin removing device comprises a handle 1, a fixing nut 2, a sleeve 3, an elastic chuck 4 and an extension rod 7, the fixing nut 2 is threadedly connected with a threaded segment provided on the extension rod 7, one end of the extension rod 7 is detachably connected with the handle 1, the other end of the extension rod 7 is detachably connected with the elastic chuck 4, the sleeve 3 has a diameter less than or equal to the interference diameter of the positioning pin, a length greater than the depth from the positioning pin to the end face of the case, and is movably sleeved on the outer circumferential wall of the extension rod 7 and reciprocates along the axial direction of the extension rod 7, an inner taper surface matched with the outer taper surface of the elastic chuck 4 is arranged in the inner hole of the end of the sleeve 3 away from the handle 1, and the end of the sleeve 3 towards the handle 1 abuts against the fixing nut 2, the inner hole wall of the elastic chuck 4 is provided with a toothed knurl 41, and the inner hole of the elastic chuck 4 is also provided with a first clamping groove 42 spaced apart from the opening end surface of the elastic chuck 4 by a certain distance.

[0054] The embodiment improves the success rate of removing the positioning pin by increasing the knurl and the clamping groove in the inner hole of the lower end of the elastic chuck 4 of the positioning pin removing device, increasing the friction coefficient when the positioning pin is removed, and forming a clamping position, the toothed knurl can improve the friction force between the elastic chuck and the positioning pin, the general steel-steel longitudinal interference joint friction coefficient μ is 0.07-0.16, and after the toothed knurl 41 is increased, the friction coefficient is about 0.3, which is twice the original, so the operator can save about 50% of the force, and the slipping phenomenon caused by insufficient friction when the positioning pin 9 is removed is avoided, the embodiment also solves the problem that the small operation space in the deep cavity of the case cannot clamp the positioning pin, and has the advantages of simple structure, low cost, convenient operation and high efficiency.

[0055] Specifically, the cross section of the toothed knurl 41 is triangular, which is convenient for processing and beneficial to increasing the friction coefficient when the positioning pin is removed.

[0056] Specifically, the hardness of the inner hole wall of the elastic chuck 4 is greater than the hardness of the positioning pin, so as to avoid deformation of the toothed knurl 41 of the inner hole wall of the elastic chuck 4 and improve the service life of the elastic chuck 4.

[0057] Specifically, the interference amount of the positioning pin and the corresponding mounting hole on the case is obtained by referring to the design data of the positioning pin and the corresponding mounting hole on the case.

[0058] Preferably, after the corresponding processing mode is selected according to the size of the obtained interference amount to pretreat the positioning pin, the positioning pin removing device is used to clamp and remove the positioning pin, and the method comprises the following steps:

[0059] S21, when the interference amount is less than 0.01, the elastic chuck 4 of the positioning pin removing device is sleeved on the positioning pin 9, the fixing nut 2 is twisted, the sleeve 3 is moved downward to press and clamp the positioning pin 9;

[0060] S22, finally, the positioning pin 9 is pulled out by applying an upward pulling force to the handle 1.

[0061] The embodiment is mainly aimed at the removal of the positioning pin with an interference amount less than 0.01. Since the interference amount is small, the teeth-shaped knurls 41 in the inner hole wall of the elastic chuck 4 can ensure sufficient friction between the elastic chuck 4 and the positioning pin 9 when clamping, so that the positioning pin 9 can be pulled out by applying an upward pulling force to the handle 1.

[0062] Preferably, according to the size of the obtained interference amount, the corresponding processing mode is selected to pretreat the positioning pin, and then the positioning pin is clamped and taken out by the positioning pin removal device, specifically including the following steps:

[0063] S21, when the interference amount is 0.01-0.015, the casing and the positioning pin 9 are first heated to make the positioning hole and the positioning pin 9 have different expansion amounts to reduce the interference amount;

[0064] S22, then the elastic chuck 4 of the positioning pin removal device is sleeved on the extended part of the positioning pin 9, and the handle is tightened to fix the nut 2, so that the sleeve 3 moves downward to press the elastic chuck 4 to clamp the positioning pin 9;

[0065] S23, finally, the positioning pin 9 is pulled out by applying an upward pulling force to the handle 1.

[0066] Specifically, the target temperature after heating is determined by the following steps during the heating process:

[0067] S211, the diameter expansion amount of the casing is △d 机匣 =a 机匣 *d0*(t1-t0), and the diameter expansion amount of the positioning pin is △d 定位销 =a 定位销 *d0*(t1-t0), where a 机匣 and a 定位孔 are the expansion coefficients of the casing and the positioning pin respectively, d0 is the initial diameter, t1 is the target temperature after heating, and t0 is the initial temperature;

[0068] S212, when the diameter expansion amount of the casing and the diameter expansion amount of the positioning pin are calculated to reduce the interference amount between the positioning hole and the positioning pin by half after the target temperature after heating t1, the current target temperature after heating t1 is taken as the final heating temperature.

[0069] The embodiment is aimed at the interference amount of 0.01-0.015, and the casing and the positioning pin 9 are first heated. Since the thermal expansion coefficient of the casing base body is about 23.6×10 -6 / ℃, and the thermal expansion coefficient of the positioning pin 9 is about 17×10 -6℃, therefore, according to the difference of thermal expansion coefficient, the interference amount is reduced by the different expansion amounts of the two materials through heating, the positioning pin is removed, and the pulling-out resistance of the positioning pin is reduced. In this embodiment, when the part is heated to 180℃, the expansion amounts of the diameter of the case and the positioning pin 9 are respectively:

[0070] △d 机匣 = 23.6 x 10 -6 / ℃*4.75mm*(180℃-20℃) = 0.017936mm;

[0071] △d 定位销 = 17 x 10 -6 / ℃*4.75mm*(180℃-20℃) = 0.012920mm;

[0072] Therefore, when the part is heated to 180℃, the interference amount can be reduced by about 0.005, and the interference amount is reduced by half, and then the positioning pin is removed by using the positioning pin removing device.

[0073] In the heating process, the heating rate is 5-6℃ / min, and the advantages include that the interference amount can be reduced by the sufficient difference of the expansion amounts of the case and the positioning pin 9, and meanwhile, the material properties of the case are not changed abnormally, and the mechanical properties are not affected. In addition, in order not to cause the precision size of the case to be out of tolerance when the case is restored to room temperature after heating, the target temperature t1 after heating is less than or equal to 200℃.

[0074] Preferably, according to the size of the interference amount, the positioning pin is pretreated by selecting a corresponding processing mode, and then the positioning pin is clamped and removed by using the positioning pin removing device, and the specific steps include:

[0075] S21, when the interference amount is 0.016-0.025, the positioning pin extending part is sleeved by using the positioning pin removing device, and then the fixed nut is tightened step by step by using a wrench, so that the elastic chuck 4 clamps the positioning pin. Each time the fixed nut is tightened, the positioning pin removing device is rotated once, and the process is repeated multiple times until the positioning pin removing device cannot be rotated, so that the final tooth-shaped knurl 41 forms multiple layers of triangular grooves 5 on the cylindrical surface of the positioning pin.

[0076] S22, the positioning pin 9 is pulled out by applying an upward pulling force to the handle 1.

[0077] With the further increase of the interference amount, the effect of reducing the interference amount by relying on the difference of the thermal expansion amounts of the case and the positioning pin is not enough, and therefore, the positioning pin 9 needs to be removed by further increasing the friction between the elastic chuck 4 and the positioning pin 9, that is, by using the tooth-shaped knurl 41 in the inner hole of the elastic chuck 4.

[0078] To this end, the present embodiment uses the positioning pin removal device to enclose the positioning pin protruding part, and then uses the wrench to tighten the fixing nut 2, wherein the inner hole of the elastic clamp 4 is knurled to increase the friction coefficient. The fixing nut 2 is tightened in steps, that is, the elastic clamp 4 is slightly stressed, and the positioning pin removal device is rotated once. After multiple forces are applied, the positioning pin removal device cannot be rotated any more. Finally, the teeth of the toothed knurl 41 form multiple layers of triangular recesses 5 on the positioning pin 9. When a force F (the pulling force of the positioning pin) is applied to the positioning pin 9, the positioning pin 9 is further subjected to a force F that is decomposed in the vertical upward direction 拉力 (see Figure 4 ), further saving the operating force, and finally realizing that the positioning pin 9 is easily pulled out by the hand-held positioning pin removal device handle.

[0079] Preferably, according to the size of the obtained interference amount, the corresponding processing mode is selected to pretreat the positioning pin, and then the positioning pin is clamped and taken out by the positioning pin removal device, specifically including the following steps:

[0080] S21. When the interference amount is above 0.025, a second clamping groove 6 is machined on the outer peripheral wall of the positioning pin exposed upper end surface at a certain distance downward;

[0081] S22. After the elastic clamp 4 of the positioning pin removal device is sleeved on the positioning pin 9, the fixing nut 2 is tightened, the sleeve 3 moves downward to press the elastic clamp 4 to clamp the positioning pin 9, and the positioning pin 9 is embedded into the first clamping groove 42 to form a clamping position 8 above the second clamping groove 6;

[0082] S23. Finally, the positioning pin 9 is pulled out by applying an upward pulling force to the handle 1.

[0083] When the interference amount further increases, when the interference amount is above 0.025, the toothed knurl 41 is not enough to increase the friction, so the positioning pin needs to be taken out by the elastic clamp and the clamping groove formed by the positioning pin, that is, the internal recess of the positioning pin removal device.

[0084] After the positioning pin is clamped by the elastic clamp, the positioning pin can be manually taken out. Because L2>L3 and L4>L1, the front end L3 of the positioning pin can be in the recess L2 of the inner hole of the elastic clamp, which forms a clamping position. In this way, the clamping force is increased when the positioning pin is taken out, and the friction at the grinding position is also increased, which makes it easier to remove the positioning pin.

[0085] Although the preferred embodiments of the present application have been described, those skilled in the art can make further changes and modifications to the embodiments once they know the basic creative concept. Therefore, the appended claims are intended to include the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0086] Obviously, many modifications and variations of the present application are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims and their equivalents, the application can be practiced otherwise than as specifically described.

Claims

1. A method of replacing a cartridge deep cavity narrow site positioning pin, characterized in that, The method comprises the steps of: Obtaining the interference amount of the positioning pin (9) and the corresponding mounting hole on the casing; After the interference amount is obtained, the corresponding processing method is selected to pre-treat the positioning pin to reduce the interference amount of the positioning pin (9) and the corresponding mounting hole on the casing or to ensure that the positioning pin removal device and the positioning pin (9) have a friction force matching the interference amount, and then the positioning pin (9) is clamped and removed by the positioning pin removal device, wherein the pre-treatment includes heat treatment or machining treatment; the positioning pin removal device comprises a handle (1), a fixed nut (2), a sleeve (3), an elastic chuck (4), and an extension rod (7), the fixed nut (2) is threadedly connected with a threaded segment provided on the extension rod (7), one end of the extension rod (7) is detachably connected with the handle (1), the other end of the extension rod (7) is detachably connected with the elastic chuck (4), the sleeve (3) has a diameter equal to or smaller than the interference diameter of the positioning pin and a length greater than the depth from the positioning pin to the end face of the casing, and the sleeve (3) is movably sleeved on the outer peripheral wall of the extension rod (7) and moves axially along the extension rod (7), an inner tapered surface matched with the outer tapered surface of the elastic chuck (4) is arranged in the inner hole of one end of the sleeve (3) away from the handle (1), and the other end of the sleeve (3) towards the handle (1) abuts against the fixed nut (2); the inner hole wall of the elastic chuck (4) is provided with tooth-shaped knurls (41), and the inner hole of the elastic chuck (4) is further provided with a first clamping groove (42) spaced apart from the opening end surface of the elastic chuck (4) by a certain distance.

2. The cartridge deep cavity narrow site positioning pin replacement method according to claim 1, characterized in that, The cross section of the tooth-shaped knurls (41) is triangular.

3. The cartridge deep cavity narrow site positioning pin replacement method of claim 1, wherein, The hardness of the inner hole wall of the elastic chuck (4) is greater than the hardness of the positioning pin.

4. The cartridge deep cavity narrow site positioning pin replacement method of claim 1 wherein, The interference amount of the positioning pin and the corresponding mounting hole on the casing is obtained by referring to the design data of the positioning pin and the corresponding mounting hole on the casing.

5. The cartridge deep cavity narrow site positioning pin replacement method of claim 1 wherein, After the interference amount is obtained, the corresponding processing method is selected to pre-treat the positioning pin to reduce the interference amount of the positioning pin (9) and the corresponding mounting hole on the casing or to ensure that the positioning pin removal device and the positioning pin (9) have a friction force matching the interference amount, and then the positioning pin (9) is clamped and removed by the positioning pin removal device, wherein the pre-treatment includes heat treatment or machining treatment; the positioning pin removal device comprises a handle (1), a fixed nut (2), a sleeve (3), an elastic chuck (4), and an extension rod (7), the fixed nut (2) is threadedly connected with a threaded segment provided on the extension rod (7), one end of the extension rod (7) is detachably connected with the handle (1), the other end of the extension rod (7) is detachably connected with the elastic chuck (4), the sleeve (3) has a diameter equal to or smaller than the interference diameter of the positioning pin and a length greater than the depth from the positioning pin to the end face of the casing, and the sleeve (3) is movably sleeved on the outer peripheral wall of the extension rod (7) and moves axially along the extension rod (7), an inner tapered surface matched with the outer tapered surface of the elastic chuck (4) is arranged in the inner hole of one end of the sleeve (3) away from the handle (1), and the other end of the sleeve (3) towards the handle (1) abuts against the fixed nut (2); the inner hole wall of the elastic chuck (4) is provided with tooth-shaped knurls (41), and the inner hole of the elastic chuck (4) is further provided with a first clamping groove (42) spaced apart from the opening end surface of the elastic chuck (4) by a certain distance. The cross section of the tooth-shaped knurls (41) is triangular. The hardness of the inner hole wall of the elastic chuck (4) is greater than the hardness of the positioning pin. The interference amount of the positioning pin and the corresponding mounting hole on the casing is obtained by referring to the design data of the positioning pin and the corresponding mounting hole on the casing.

6. The cartridge deep cavity narrow site positioning pin replacement method of claim 5, wherein, After the interference amount is obtained, the corresponding processing method is selected to pre-treat the positioning pin to reduce the interference amount of the positioning pin (9) and the corresponding mounting hole on the casing or to ensure that the positioning pin removal device and the positioning pin (9) have a friction force matching the interference amount, and then the positioning pin (9) is clamped and removed by the positioning pin removal device, wherein the pre-treatment includes heat treatment or machining treatment; the positioning pin removal device comprises a handle (1), a fixed nut (2), a sleeve (3), an elastic chuck (4), and an extension rod (7), the fixed nut (2) is threadedly connected with a threaded segment provided on the extension rod (7), one end of the extension rod (7) is detachably connected with the handle (1), the other end of the extension rod (7) is detachably connected with the elastic chuck (4), the sleeve (3) has a diameter equal to or smaller than the interference diameter of the positioning pin and a length greater than the depth from the positioning pin to the end face of the casing, and the sleeve (3) is movably sleeved on the outer peripheral wall of the extension rod (7) and moves axially along the extension rod (7), an inner tapered surface matched with the outer tapered surface of the elastic chuck (4) is arranged in the inner hole of one end of the sleeve (3) away from the handle (1), and the other end of the sleeve (3) towards the handle (1) abuts against the fixed nut (2); the inner hole wall of the elastic chuck (4) is provided with tooth-shaped knurls (41), and the inner hole of the elastic chuck (4) is further provided with a first clamping groove (42) spaced apart from the opening end surface of the elastic chuck (4) by a certain distance. The diameter expansion amount of the cartridge is determined as Δd 机匣 = a 机匣 * d0* (t1-t0), the diameter expansion amount of the positioning pin is Δd 定位销 = a 定位销 * d0* (t1-t0), wherein a 机匣 and a 定位销 are expansion coefficients of the cartridge and the positioning pin respectively, d0 is the initial diameter, t1 is the target temperature after heating, and t0 is the initial temperature. ​ 7. The cartridge deep pocket narrow site positioning pin replacement method of claim 6, wherein, ​ 8. The cartridge deep cavity narrow site positioning pin replacement method of claim 1 wherein, ​ When the interference is between 0.016 and 0.025, the positioning pin extension part is sleeved by the positioning pin removing device, then the fixed nut is tightened step by step by using a wrench, the elastic chuck (4) clamps the positioning pin, the positioning pin removing device is rotated once every time the fixed nut (2) is tightened, and the process is repeated until the positioning pin removing device cannot be rotated, so that the final tooth-shaped knurl (41) forms a plurality of triangular grooves (5) on the cylindrical surface of the positioning pin; Finally, the positioning pin (9) is pulled out by applying an upward pulling force to the handle (1).

9. The cartridge deep cavity narrow site positioning pin replacement method of claim 1 wherein, According to the size of the obtained interference, the positioning pin is pretreated by selecting a corresponding processing mode, then the positioning pin is clamped and taken out by the positioning pin removing device, and the method specifically comprises the following steps: When the interference is above 0.025, a second clamping groove (6) is machined on the outer peripheral wall of the positioning pin at a distance below the exposed upper end surface of the positioning pin; After the elastic chuck (4) of the positioning pin removing device is sleeved on the positioning pin (9), the fixed nut (2) is tightened, the sleeve (3) moves downward to press the elastic chuck (4) to clamp the positioning pin (9), so that the part of the positioning pin (9) above the second clamping groove (6) is embedded into the first clamping groove (42) to form a clamping position (8); Finally, the positioning pin (9) is pulled out by applying an upward pulling force to the handle (1).

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