Polishing and grinding device for inner hole of aerospace pipe and using method of polishing and grinding device

Abstract

The invention discloses an aerospace pipe inner hole polishing and grinding device and a use method thereof, and solves the problems of low efficiency, poor surface quality and material waste in the prior art by matching a plurality of polishing and grinding assemblies with a reversible driving and feeding mechanism. The method is suitable for high-temperature alloy pipes such as GH4169 and TC4, the machining efficiency is improved by 50%, the abrasive belt utilization rate reaches 90% or above, and the strict requirements of the aerospace field for surface roughness and wall thickness uniformity are met.

Description

Technical Field

[0001] This invention relates to the field of seamless tube processing technology, specifically to an aerospace tube inner hole polishing device and its usage method. Background Technology

[0002] In the aerospace manufacturing field, the surface quality of the inner bore of tubing (such as GH4169 high-temperature alloy tubing) directly affects fluid transmission efficiency, corrosion resistance, and fatigue life. The industry has stringent requirements regarding surface roughness, dimensional adaptability, and processing efficiency. However, current technologies in the field of aerospace tubing inner bore polishing still have many problems that urgently need to be solved, specifically as follows: First, the processing efficiency is generally low. Existing technologies mostly adopt a single-wheel, unidirectional polishing structure. To complete the polishing of the inner hole of a tube, it is necessary to carry out rough grinding, fine grinding and other processes in stages. Each process requires stopping the machine, clamping and changing the abrasive belt of the corresponding grit size. The operation is cumbersome and time-consuming. Statistics show that the total time for processing a single aerospace tube using this method usually exceeds 15 minutes, which is difficult to meet the efficiency requirements of mass production.

[0003] Secondly, the surface quality stability of the inner hole is poor. Most existing polishing devices use rigid grinding head structures with fixed external dimensions, which cannot adapt to the common ±0.1mm inner diameter tolerance fluctuations in pipes. During the polishing process, the rigid grinding head is prone to localized poor contact or excessive compression with the inner wall of the pipe, making it difficult to stably control the surface roughness of the inner hole below Ra0.4μm. Some products are even scrapped due to substandard surface quality.

[0004] Third, the utilization rate of polishing consumables is low and the proportion of auxiliary working time is high. Commonly used polishing consumables in existing technologies, such as flap wheels, sandpaper, and single-piece abrasive belts, are limited by their structure. Only the surface abrasive of these consumables can participate in polishing. Once the surface abrasive is worn out, the entire polishing consumable needs to be replaced, resulting in an overall utilization rate of less than 30%. The frequent replacement of consumables not only increases material costs but also causes auxiliary downtime to account for more than 40% of the total processing time, further exacerbating the contradiction between processing efficiency and cost control. Summary of the Invention

[0005] In view of the above-mentioned shortcomings of the existing technology, the purpose of the present invention is to provide an aerospace tube inner hole polishing device and its usage method, so as to solve the problems of low processing efficiency, poor inner hole surface quality stability, low utilization rate of polishing consumables and high proportion of auxiliary time caused by frequent replacement of polishing consumables in the existing technology.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A device for polishing the inner bore of aerospace tubing includes a drive mechanism and a transmission rod. One end of the transmission rod is fixedly connected to the drive end of the drive mechanism, enabling the drive mechanism to drive the transmission rod to rotate around its axis. Multiple polishing components are mounted on the other end of the transmission rod, each component being sleeved on and detachably fixedly connected to the transmission rod, and capable of rotating with the transmission rod around its axis. Each polishing component includes at least two sets of abrasive belt assemblies, which are arranged in a cross-overlapping configuration such that the length directions of the two sets of abrasive belt assemblies are perpendicular to each other. A fixed disc is provided at the intersection of the two sets of abrasive belt assemblies. The fixed disc has a hollow structure, allowing both ends of the two sets of abrasive belt assemblies to pass through the hollow structure of the fixed disc and extend to the outside of the fixed disc, so that the two ends of the abrasive belt assemblies can fit against the inner wall of the pipe to be polished. The abrasive belt assembly is elastic. When the drive end of the drive mechanism drives the transmission rod to rotate around the axis of the transmission rod, the two ends of the abrasive belt assembly can extend away from the transmission rod under the action of centrifugal force and apply friction to the inner wall of the pipe to be polished.

[0007] Preferably, the abrasive belt assembly consists of multiple abrasive belts, the two ends of which are fixedly connected to form an annular abrasive belt; one abrasive belt is sleeved on the outside of another abrasive belt, and the length direction of the multiple abrasive belts is consistent, thereby forming an abrasive belt assembly; the abrasive belt is elastic.

[0008] Preferably, it also includes a feeding mechanism, which is used to control the movement of the drive mechanism, so that the polishing assembly can move along the length of the tube to be polished, and finally achieve the polishing treatment of the inner wall of the tube to be polished.

[0009] Preferably, silicon carbide particles are coated on the side of the abrasive belt facing the pipe to be polished, and the particle size of the silicon carbide particles is 80#-2000#.

[0010] Preferably, when the transmission rod is located inside the tube to be polished, the rotation direction of the polishing assembly is opposite when the transmission rod moves toward the tube to be polished and when the transmission rod moves away from the tube to be polished; the driving mechanism is a reversible motor.

[0011] Preferably, the thickness of the abrasive belt assembly is 3mm-5mm, the thickness of each abrasive belt layer is 0.4mm-0.6mm, and adjacent abrasive belt layers are bonded together with an adhesive.

[0012] Preferably, a connecting hole is provided at the center of the fixed disc, and an opening is provided on the frosted belt assembly at the position corresponding to the connecting hole, through which the transmission rod passes.

[0013] Preferably, a spring steel base plate is provided on the fixed disc at the position corresponding to the sanding belt. The spring steel base plate is located on the outer surface of the sanding belt assembly. One end of the spring steel base plate is fixedly connected to the fixed disc, and the other end extends along the length of the sanding belt, so that the spring steel base plate is in contact with the outermost surface of the sanding belt.

[0014] This invention also provides a method for polishing the inner wall of aerospace tubing, using the aforementioned inner wall polishing device to polish the inner wall of the tubing. The specific steps are as follows: Step 1: Fix the pipe to be processed on the workbench, and then place the inner hole polishing device in the corresponding position so that the polishing component on the transmission rod is located inside the pipe opening; Step 2: Start the drive mechanism and feed mechanism. The drive mechanism drives the transmission rod to rotate around its own axis, which in turn drives the polishing assembly to rotate. At the same time, the feed mechanism drives the transmission rod to move along the length of the pipe towards the pipe. During the movement, the polishing assembly polishes the inner wall of the pipe. After polishing is completed, the drive mechanism changes the direction of rotation, causing the polishing assembly to rotate in the opposite direction. The feed mechanism drives the transmission rod to move along the length of the pipe away from the pipe. During the movement, the polishing assembly further polishes the inner wall of the pipe. Step 3: After polishing is complete, turn off the drive mechanism and the feed mechanism, and remove the pipe from the worktable.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention addresses the technical problems existing in the internal hole polishing technology of aerospace tubes. By using multiple polishing components in conjunction with a reversible drive and feeding mechanism, the polishing components can operate in both forward and reverse directions when inserting and withdrawing from the tube. Furthermore, different grit silicon carbide abrasive belts can be used for rough and fine grinding according to the needs of rough grinding and fine grinding, which is convenient to switch between. The processing time of a single tube is reduced to less than 1 / 3 of that of the existing technology, which far exceeds the expected efficiency of simply optimizing the clamping.

[0016] 2. This invention addresses the issue that existing rigid grinding heads cannot accommodate an inner diameter tolerance of ±0.1mm, resulting in poor adaptability and difficulty in controlling the roughness below Ra0.4μm. This invention employs an elastic abrasive belt with precise control of the drive speed to achieve dynamic adjustment of centrifugal force, adapting to inner diameter fluctuations. Combined with a spring steel substrate to enhance fit, the inner hole roughness is stably controlled within Ra0.2μm-Ra0.3μm, completely solving the localized fit problem and achieving stability superior to simply meeting the initial tolerance adaptation target.

[0017] 3. This invention also optimizes both consumables and working hours. Existing technologies have a consumables utilization rate of less than 30% and auxiliary material replacement time of more than 40%. This invention uses a multi-layer bonded annular abrasive belt to make full use of each layer of abrasive. Combined with a design that avoids frequent replacements, it increases the consumables utilization rate to more than 80% and reduces the proportion of auxiliary working hours to less than 10%, achieving unexpected synergistic benefits of consumables saving and efficiency improvement. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the polishing device of the present invention during forward feeding.

[0019] Figure 2 This is a schematic diagram of the polishing device of the present invention during reverse feeding.

[0020] Figure 3 This is a schematic diagram of the structure of the abrasive belt assembly in this invention.

[0021] Figure 4 This is a schematic diagram of the structure of the fixed disk in this invention.

[0022] In the diagram: 1. Transmission rod; 2. Frosted belt assembly; 3. Fixed disc; 4. Connecting hole; 5. Pipe. Detailed Implementation

[0023] This invention will describe the technical solutions of the embodiments of the invention clearly and completely. Obviously, the described embodiments are only some embodiments of the invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on this invention are within the scope of protection of this invention.

[0024] Unless otherwise specified in the specific circumstances, the numerical ranges listed herein include upper and lower limits, as well as all integers and fractions within that range, but are not limited to the specific values ​​listed when the range is defined.

[0025] I. An aerospace pipe inner hole polishing device The aerospace tubing inner hole polishing device of the present invention is as follows: Figure 1-3As shown, the device includes a drive mechanism and a transmission rod 1. One end of the transmission rod is fixedly connected to the drive end of the drive mechanism, enabling the drive mechanism to drive the transmission rod to rotate around its axis. Multiple polishing components are mounted on the other end of the transmission rod. These polishing components are sleeved on the transmission rod and detachably fixedly connected to it, and can rotate with the transmission rod around its axis. Fixing nuts are provided on both sides of each polishing component along the length of the transmission rod, securing the polishing component firmly in a predetermined position. When the polishing component needs to be replaced, removing the fixing nuts on both sides allows for replacement. The polishing assembly includes at least two sets of abrasive belt assemblies 2, which are arranged in a cross-overlapping manner such that their length directions are perpendicular to each other. A fixed disc 3 is provided at the intersection of the two sets of abrasive belt assemblies. This fixed disc has a hollow structure, allowing both ends of the two sets of abrasive belt assemblies to pass through the hollow structure of the fixed disc and extend beyond it, enabling the ends of the abrasive belt assemblies to adhere to the inner wall of the pipe to be polished. The abrasive belt assemblies are elastic; when the drive end of the drive mechanism drives the transmission rod to rotate around the axis of the transmission rod, the ends of the abrasive belt assemblies can extend away from the transmission rod under the action of centrifugal force, applying friction to the inner wall of the pipe to be polished. During high-speed rotation (2000rpm-3000rpm), the abrasive belt assemblies open outwards and adhere to the inner wall of the pipe through centrifugal force, with a contact pressure of 5-10N, suitable for pipes with an inner diameter tolerance of ±0.1mm.

[0026] This invention addresses the technical problems of existing technologies by improving the pipe inner hole polishing device. Firstly, to address low processing efficiency, it employs a combination of multiple polishing components and a reversible motor, achieving integrated polishing through reciprocating movement and continuous rotation, avoiding phased downtime. Secondly, to address unstable surface quality, it utilizes elastic, cross-laid abrasive belt components, employing centrifugal force to dynamically conform to the inner hole wall, replacing the rigid grinding head to solve tolerance matching issues. Finally, to address low consumable utilization, it incorporates a ring-shaped multi-layered abrasive belt structure to maximize abrasive participation and reduce waste. This invention features multiple polishing components on the drive rod, enabling polishing of the inner hole wall during both insertion and removal, accelerating the polishing process. Furthermore, the elasticity of the abrasive belt components allows for applicability to various pipe sizes; even fluctuations in the inner diameter tolerance of the pipe do not affect the normal operation of the polishing device. Moreover, precise control of the polishing force can be achieved by controlling the rotational speed of the drive mechanism, ensuring that the surface roughness of the inner hole meets production requirements. In practical use, the polishing device is placed at the opening of the pipe to be polished. Because the abrasive belt assembly is elastic, it can be moved to bend, allowing the polishing assembly to be inserted into the pipe. At this point, both ends of the abrasive belt assembly are tightly fitted against the inner wall of the pipe. Figure 1 As shown. Then, the drive mechanism is activated. Driven by the drive mechanism, the transmission rod begins to rotate around its axis, causing multiple polishing components on the transmission rod to rotate together. This allows the abrasive belt assembly to polish the inner wall of the pipe while rotating. During the polishing process, the polishing device is moved, causing the transmission rod to move along the length of the pipe, thus enabling the abrasive belt assembly to perform overall polishing of the inner wall of the pipe. Simultaneously, during the polishing process, the centrifugal force of the abrasive bag assembly can be adjusted by controlling the rotation speed of the transmission rod, thereby controlling the polishing force of the abrasive belt assembly on the inner wall of the pipe.

[0027] In some embodiments of the present invention, the abrasive belt assembly consists of multiple abrasive belts, the two ends of which are fixedly connected to form an annular abrasive belt; one abrasive belt is fitted over the outside of another abrasive belt, and the length directions of the multiple abrasive belts are consistent, thereby forming the abrasive belt assembly; the abrasive belts are elastic. The thickness of the abrasive belt assembly is 3mm-5mm, and the thickness of each layer of abrasive belt is 0.4mm-0.6mm, with adjacent layers of abrasive belts bonded together by an adhesive. The multi-layered abrasive belts, fixed in a nested manner, form a thicker abrasive belt assembly. Thus, when the outer abrasive belt wears down, the inner abrasive belt is automatically exposed and participates in polishing. Compared with commonly used abrasive wheels in the prior art, this method has higher utilization and lower replacement frequency.

[0028] In some embodiments of the present invention, a feeding mechanism is also included. This feeding mechanism controls the movement of the drive mechanism, thereby enabling the polishing assembly to move along the length of the tube to be polished, ultimately achieving polishing treatment of the inner wall of the tube. Specifically, the feeding mechanism includes a worktable with a linear motor fixed to one side. The drive end of the linear motor is fixedly connected to one end of a push rod, and the other end of the push rod is fixedly connected to the drive mechanism of the polishing device of the present invention. Driven by the linear motor, the drive mechanism can reciprocate along a straight line. This feeding mechanism is prior art and can be controlled by various mechanical devices to move the drive mechanism, thereby enabling the polishing assembly to move along the length of the tube to be polished. In practical applications, linear motors can be linear stepper motors, permanent magnet synchronous linear motors, coreless U-shaped linear motors, cylindrical linear motors, high-temperature / vacuum special linear motors, etc. These linear motors all have corresponding product models and can all achieve the above-mentioned technical effects. Therefore, this invention does not specifically limit the feeding mechanism. The above-mentioned feeding mechanism is an example of the technical solution described in this invention in actual implementation.

[0029] In some embodiments of the present invention, silicon carbide particles are coated on the surface of the abrasive belt facing the pipe to be polished. The particle size of the silicon carbide particles is 80#-2000#. The particle size of the silicon carbide particles can be adjusted according to the polishing requirements. When coarse grinding is required, the particle size of the silicon carbide particles is 80#-400#; when fine grinding is required, the particle size of the silicon carbide particles is 800#-2000#. Coarse grinding belt assemblies and fine grinding belt assemblies can be set up according to the needs of the polishing process. The difference between the two lies in the particle size of the silicon carbide particles. The coarse grinding belt assembly is used when coarse grinding is required, and the fine grinding belt assembly is used when fine grinding is required. The replacement speed of the two is not slow, enabling rapid replacement. Alternatively, to further reduce replacement time, a coarse grinding area and a fine grinding area can be set on the same drive rod. A coarse grinding abrasive belt assembly is installed in the coarse grinding area, and another coarse grinding abrasive belt assembly is installed in the fine grinding area. After coarse grinding is completed, the position of the drive rod is moved to allow the fine grinding area to enter the pipe for fine grinding. Alternatively, the drive mechanism can be a dual-axis output motor with two completely independent drive shafts located at opposite ends of the motor. Drive rods with pre-fixed abrasive bag assemblies are installed on each of the two drive shafts, allowing simultaneous polishing of the inner walls of two pipes. The design of bidirectional drive motors revolves around a dual-output shaft structure, mainly including dual-axis stepper motors (e.g., NEMA17 dual-axis stepper motor, NEMA23 dual-axis stepper motor, etc.), dual-axis servo motors (e.g., Orui Transmission SD20-D series, Siemens SINAMICSS120 dual-axis module, etc.), and dual-axis DC geared motors (e.g., N20 dual-axis worm gear motor, external rotor hub dual-axis motor, etc.). Regardless of the implementation method described above, based on the abrasive belt assembly designed in this invention, even the time required to replace different abrasive belt assemblies is far less than the time required to replace abrasive wheels in the prior art.

[0030] In some embodiments of the present invention, when the drive rod is located inside the pipe to be polished, the rotation direction of the polishing assembly is opposite when the drive rod moves towards the pipe to be polished and when the drive rod moves away from the pipe to be polished; the driving mechanism is a reversible motor. When the drive rod moves towards the pipe to be polished, this direction of movement is called forward feed; when the drive rod moves away from the pipe to be polished, this direction of movement is called reverse feed. The speed of forward and reverse feed is 50-100 mm / min, and the rotation direction of the polishing assembly is opposite during forward and reverse feeds. For example, if the polishing assembly rotates clockwise during forward feed, then it rotates counterclockwise during reverse feed. This design aims to ensure that the marks formed on the inner wall of the pipe after polishing exhibit a cross-shaped mesh texture. This is because the inner bore of aerospace tubing (such as GH4169 high-temperature alloy tubing) needs to meet stringent requirements for fluid transport efficiency and fatigue strength. The direction of the wear marks on the inner bore surface directly affects the flow resistance and stress concentration risk. This invention, through a design that switches between forward (clockwise rotation) and reverse (counterclockwise rotation) feeds or vice versa, creates a cross-shaped mesh texture on the cutting path of the abrasive belt against the inner wall during polishing, rather than a unidirectional spiral mark. This texture structure can reduce fluid flow resistance by 15% and increase the fatigue life of the inner wall of the tubing by more than 20%, solving the problems of "localized eddies" and "stress concentration" caused by the single direction of the wear marks in traditional unidirectional polishing.

[0031] In some embodiments of the present invention, the structure of the fixed disk is as follows: Figure 4 As shown, the fixed disc 3 is made of metal. A connecting hole 4 is located in the center of the fixed disc 3, and an opening is provided on the abrasive belt assembly at the corresponding position of the connecting hole. The transmission rod passes through both the connecting hole and the opening. The fixed disc 3 is cylindrical and hollow inside. Multiple through holes 6 are also provided on the cylindrical sidewall of the fixed disc. These through holes are evenly distributed along the circumference of the fixed disc, and each through hole communicates with the hollow internal structure of the fixed disc. Both ends of the two sets of abrasive belts arranged in a cross configuration can extend from the through holes of the fixed disc, thus tightly fitting against the inner wall of the pipe to be polished.

[0032] In some embodiments of the present invention, a spring steel base plate is further provided on the fixed disc at the position corresponding to the sanding belt. The spring steel base plate is located on the outer surface of the sanding belt assembly. One end of the spring steel base plate is fixedly connected to the fixed disc, and the other end extends along the length of the sanding belt, so that the spring steel base plate is in contact with the outermost surface of the sanding belt. The spring steel base plate is used to assist in bending the sanding belt assembly, so that the two ends of the sanding belt assembly can form a certain included angle α with the axis of the drive rod in its natural state. This included angle α is 15°-20°, ensuring that the two ends of the sanding belt assembly can better and more tightly fit the inner wall of the pipe.

[0033] II. A method for polishing the inner hole of aerospace tubing The inner wall of the pipe is polished using the inner hole polishing device described in this invention. The specific steps are as follows: Step 1: Fix the pipe to be processed on the workbench, and then place the inner hole polishing device in the corresponding position so that the polishing component on the transmission rod is located inside the pipe opening; Step 2: Start the drive mechanism and feed mechanism. The drive mechanism drives the transmission rod to rotate around its own axis, simultaneously rotating the polishing assembly. Simultaneously, the feed mechanism drives the transmission rod to move along the length of the pipe towards the pipe, during which the polishing assembly polishes the inner wall of the pipe. After polishing, the drive mechanism changes its rotation direction, causing the polishing assembly to rotate in the opposite direction. The feed mechanism then drives the transmission rod to move along the length of the pipe away from the pipe, further polishing the inner wall of the pipe during this movement. The feed speed is controlled at 50-100 mm / min. The feed mechanism includes a worktable with a linear motor fixed to one side. The drive end of the linear motor is fixedly connected to one end of a push rod, and the other end of the push rod is fixedly connected to the drive mechanism of the polishing device described in this invention. Driven by the linear motor, the drive mechanism can reciprocate along a straight line.

[0034] Step 3: After polishing is complete, turn off the drive mechanism and the feed mechanism, and remove the pipe from the worktable.

[0035] The polishing method described in this invention can achieve both coarse and fine grinding of the inner wall of the pipe in actual use. The steps of coarse and fine grinding are exactly the same. The difference lies in the use of the corresponding polishing belt assembly, such as the coarse grinding belt assembly and the fine grinding belt assembly.

[0036] The polishing device and method described in this invention not only improve efficiency through reciprocating rotary polishing, but also eliminates the quality differences caused by unidirectional processing at both ends of the pipe in the prior art due to the balancing effect of bidirectional friction, thus controlling the surface roughness deviation within 0.05μm along the entire length of the inner hole. Moreover, the synergistic effect of the elastic abrasive belt and the spring steel base not only accommodates larger tolerances, but also automatically compensates for the wear of the abrasive belt during polishing, extending the service life of a single set of abrasive belts to 2.5 times that of existing products, further reducing the frequency of replacement. Finally, the integrated processing mode greatly simplifies the operation process, shortens the operator training cycle by 50%, and reduces the pipe positioning error caused by frequent clamping, controlling the consistency deviation of the inner hole size in batch production within 0.02mm. This provides a better path for the large-scale manufacturing of aerospace pipes that balances efficiency, quality, and cost.

[0037] III. Examples and Comparative Examples Example 1: Processing of GH4169 high-temperature alloy pipes 1. Pipe parameters: Φ12×1.5mm, length 1500mm; 2. Polishing assembly configuration: coarse grinding belt assembly (3 layers of 120# silicon carbide abrasive belt), fine grinding belt assembly (3 layers of 1500# silicon carbide abrasive belt), metal fixed disc with a diameter of 12mm; 3. Processing parameters: rotation speed 2500 rpm, feed rate 60 mm / min, bonding pressure 8 N; 4. After polishing the inner wall of the pipe using the polishing method described in this invention: the surface roughness Ra is 0.2μm, the wall thickness deviation is ≤0.02mm, the sand belt utilization rate is 91%, and the processing efficiency is 45% higher than that of traditional honing.

[0038] Example 2: Processing of TC4 Titanium Alloy Tubes 1. Pipe parameters: Φ10×0.5mm, length 800mm; 2. Polishing assembly configuration: coarse grinding belt assembly (4 layers of 120# silicon carbide abrasive belt), fine grinding belt assembly (4 layers of 2000# silicon carbide abrasive belt), metal fixed disc with a diameter of 8mm; 3. Processing parameters: Rotation speed 2200 rpm, feed rate 55 mm / min, bonding pressure 6 N; 4. Results: Surface roughness Ra 0.3 μm, no scratches.

[0039] Comparative Example 1 The 12×1.5mm GH4169 high-temperature alloy pipe in Example 1 was polished using a rigid abrasive wheel (Φ12mm resin-bonded diamond abrasive wheel, grit size 120# / 1500#) with existing technology. The specific results after polishing are as follows: Surface roughness: Ra 0.8μm-1.2μm, with a deviation of up to 0.4μm along the length of the pipe (Ra 0.8μm at the inlet end and Ra 1.2μm at the outlet end). Wall thickness deviation: ±0.08mm, far exceeding ≤0.02mm in Example 1; Processing efficiency: The total processing time for a single pipe is 18 minutes (8 minutes for rough grinding + 10 minutes for fine grinding, including 2 stops to change grinding wheels), which is 58% less efficient than the present invention (7.5 minutes); Consumable utilization rate: The grinding wheel needs to be replaced as soon as the surface abrasive wears off, with a utilization rate of only 25%. The cost of a single tube is three times that of Example 1. Surface quality: 30% of the pipes had local scratches (depth 0.01mm-0.03mm), and 15% had "unpolished areas" due to poor fit between the rigid grinding head and the inner wall.

[0040] By comparing and analyzing the embodiments and Comparative Example 1, it can be seen that: (1) Compared with the embodiments, Comparative Example 1 has low processing efficiency and complicated procedures. The existing technology requires two separate processes: rough grinding and fine grinding. Each time the grinding wheel is changed, the machine needs to be stopped for clamping (which takes 2 minutes / time), and the auxiliary time accounts for 45%. However, the present invention, through the design of "bidirectional rotation + multi-layer sand belt", can complete the integrated rough and fine grinding process in a single round trip, reducing the auxiliary time to less than 10%, and there is no need to stop the machine to change consumables.

[0041] (2) Compared with the examples, the surface quality stability of Comparative Example 1 after processing is poor and cannot adapt to the inner diameter tolerance. The abrasive wheel is a rigid structure and cannot adapt to the fluctuation of the inner diameter tolerance of the pipe within ±0.1mm. This leads to: ① When using the abrasive wheel to polish the inner wall of the pipe, local areas will be "burned" (the surface turns black) due to excessive pressure; ② The original processing marks remain in the areas where the fit is not solid. The present invention dynamically adjusts the centrifugal force of the elastic abrasive belt (fitting pressure 5-10N) and enhances the fit with a spring steel base plate, so that the roughness is stably controlled within Ra0.2μm-Ra0.3μm, and the tolerance adaptability is improved by 300%.

[0042] (3) The consumable utilization rate of Comparative Example 1 is extremely low, resulting in poor economic efficiency. This is because only 30% of the abrasive in the surface layer of the grinding wheel participates in polishing, and the inner layer abrasive is not fully utilized before it needs to be replaced, leading to high cost per tube grinding wheel. The present invention uses a multi-layer annular abrasive belt (3 layers bonded together), which uses bidirectional rotation to ensure uniform consumption of abrasive in each layer, increasing the utilization rate to 91% and reducing consumable costs by 67%.

[0043] (4) Comparative Example 1 is prone to pipe deformation and insufficient processing accuracy when processing thin-walled pipes. The wall thickness of GH4169 pipe is only 1.5mm. The unidirectional pressure (15-20N) of the rigid grinding wheel can easily cause the pipe to bend (straightness deviation 0.15mm / m). However, the present invention controls the processing pressure to 8N through the force balance effect of bidirectional rotation, and the straightness deviation is ≤0.03mm / m, thus solving the problem of "rigid force-induced deformation".

[0044] (5) The processing method of Comparative Example 1 has poor consistency in mass production. Traditional grinding wheels need to be recalibrated and repositioned after replacement, resulting in a deviation of ±0.05mm in the inner diameter of the pipes processed in batches. However, the present invention, through the design of "no need to replace the sanding belt + centrifugal force self-positioning", controls the dimensional consistency deviation within ±0.02mm, which meets the stringent requirements of aerospace mass production.

[0045] The polishing device and method described in this invention can significantly improve processing efficiency. The reciprocating polishing allows for rough and fine polishing to be completed in a single stroke, reducing processing time to 50% of traditional equipment (from 15 minutes to 7.5 minutes). Furthermore, the polishing quality is very stable, with the centrifugal force self-adhesion design ensuring a surface roughness of Ra0.2-Ra0.4μm and a wall thickness deviation of ≤0.03mm. At the same time, it is very economical, with the multi-layer abrasive belt structure reducing consumable costs by 60% and increasing abrasive belt utilization from 30% to over 90%.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit the technical solutions. Those skilled in the art should understand that any modifications or equivalent substitutions to the technical solutions of the present invention without departing from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. An aerospace tube inner hole polishing device, comprising a drive mechanism and a transmission rod (1), one end of the transmission rod being fixedly connected to the drive end of the drive mechanism, enabling the drive mechanism to drive the transmission rod to rotate around the axis of the transmission rod; characterized in that, Multiple polishing components are provided on the other end of the transmission rod. The polishing components are sleeved on the transmission rod and detachably fixedly connected to the transmission rod, and can rotate around the axis of the transmission rod together with the transmission rod. The polishing assembly includes at least two sets of abrasive belt assemblies (2), which are arranged to overlap each other so that the length directions of the two sets of abrasive belt assemblies are perpendicular to each other; a fixed disc (3) is provided at the intersection of the two sets of abrasive belt assemblies. The fixed disc has a hollow structure so that both ends of the two sets of abrasive belt assemblies can pass through the hollow structure of the fixed disc and extend to the outside of the fixed disc, so that both ends of the abrasive belt assemblies can fit against the inner wall of the pipe to be polished. The abrasive belt assembly is elastic. When the drive end of the drive mechanism drives the transmission rod to rotate around the axis of the transmission rod, both ends of the abrasive belt assembly can extend away from the transmission rod under the action of centrifugal force and apply frictional force to the inner wall of the pipe to be polished.

2. The internal hole polishing device according to claim 1, characterized in that, The abrasive belt assembly consists of multiple abrasive belts, with their two ends fixedly connected to form an annular abrasive belt; one abrasive belt is fitted over the outside of another abrasive belt, and the length directions of the multiple abrasive belts are consistent, thereby forming the abrasive belt assembly; the abrasive belts are elastic.

3. The internal hole polishing device according to claim 1, characterized in that, It also includes a feeding mechanism, which controls the movement of the drive mechanism so that the polishing assembly can move along the length of the pipe to be polished, and finally achieve the polishing treatment of the inner wall of the pipe.

4. The internal hole polishing device according to claim 2, characterized in that, The side of the abrasive belt facing the pipe to be polished is coated with silicon carbide particles, the particle size of which is 80#-2000#.

5. The internal hole polishing device according to claim 1, characterized in that, When the transmission rod is located inside the tube to be polished, the rotation direction of the polishing assembly is opposite when the transmission rod moves toward the tube to be polished and when the transmission rod moves away from the tube to be polished; the driving mechanism is a reversible motor.

6. The internal hole polishing device according to claim 1, characterized in that, The thickness of the abrasive belt assembly is 3mm-5mm, and the thickness of each abrasive belt layer is 0.4mm-0.6mm. Adjacent abrasive belt layers are bonded together with adhesive.

7. The internal hole polishing device according to claim 1, characterized in that, A connecting hole (4) is provided in the center of the fixed disc, and an opening is provided on the frosted belt assembly at the position corresponding to the connecting hole. The transmission rod passes through both the connecting hole and the opening.

8. The internal hole polishing device according to claim 1, characterized in that, A spring steel base plate is also provided on the fixed disc at the position corresponding to the sanding belt. The spring steel base plate is located on the outer surface of the sanding belt assembly. One end of the spring steel base plate is fixedly connected to the fixed disc, and the other end extends along the length of the sanding belt, so that the spring steel base plate is in contact with the outermost sanding belt surface.

9. A method for polishing the inner hole of aerospace tubing, characterized in that, The inner wall of the pipe is polished using the inner hole polishing apparatus described in any one of claims 1-8, and the specific steps are as follows: Step 1: Fix the pipe to be processed on the workbench, and then place the inner hole polishing device in the corresponding position so that the polishing component on the transmission rod is located inside the pipe opening; Step 2: Start the drive mechanism and feed mechanism. The drive mechanism drives the transmission rod to rotate around its own axis, which in turn drives the polishing assembly to rotate. At the same time, the feed mechanism drives the transmission rod to move along the length of the pipe towards the pipe. During the movement, the polishing assembly polishes the inner wall of the pipe. After polishing is completed, the drive mechanism changes the direction of rotation, causing the polishing assembly to rotate in the opposite direction. The feed mechanism drives the transmission rod to move along the length of the pipe away from the pipe. During the movement, the polishing assembly further polishes the inner wall of the pipe. Step 3: After polishing is complete, turn off the drive mechanism and the feed mechanism, and remove the pipe from the worktable.

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