A method for processing a slender thin-walled sleeve, the thin-walled sleeve and the open sleeve

Abstract

This application provides a method for machining a slender, thin-walled sleeve, the thin-walled sleeve, and an open sleeve. The method includes: Step 1: Fixing the sleeve body on a machine tool using a clamping and lifting method, and machining the outer diameter of the first part of the sleeve body; wherein the outer diameter of the first part is respectively semi-finished, finished, and finely machined; Step 2: Rotating the sleeve body for a second clamping, and machining the outer diameter of the second part of the sleeve body; Step 3: Clamping the excess material at one end of the sleeve head, and machining the outer diameter of the sleeve head; Step 4: Sequentially machining the first bottom hole, the first internal thread hole, the first sealing surface, the second bottom hole, and the first end face of the sleeve head; Step 5: Sequentially machining the first external thread and the relief groove of the sleeve head; Step 6: Inserting the second part of the sleeve body into the second bottom hole of the sleeve head, and fixing it by laser welding. This invention can ensure the sealing performance of the cylinder pressure sensor and the sleeve, and has the advantages of high yield and high quality.

Description

Technical Field

[0001] This application relates to the field of machining technology, and more specifically, to a method for machining a slender thin-walled sleeve, a thin-walled sleeve, an open sleeve, a chuck structure, and an external threading tool. Background Technology

[0002] Currently, the cylinder pressure sensor sleeve is a key component in engine cylinder pressure testing. As a core component, the cylinder pressure sensor sleeve has long been highly dependent on imports, resulting in high manufacturing and procurement costs. Moreover, this product is small in size, has high precision, is made of stainless steel, and requires a high gas sealing performance with the cylinder pressure sensor after processing. At present, the domestic processing experience for this product is still in its early stages, and it mainly relies on external imports.

[0003] Existing thin-walled sleeve processing methods result in poor sealing performance between the sleeve and the cylinder pressure sensor, and difficulty in machining the straightness of the sleeve, leading to poor product quality, low yield, and inability to achieve mass production. Summary of the Invention

[0004] The purpose of this application is to provide a method for processing a slender, thin-walled sleeve, a thin-walled sleeve, and an open sleeve, which solves the problem of uncontrollable part quality due to the high linear accuracy of the thin-walled sleeve, as well as the technical problem of poor sealing between the sealing end face and the first sealing surface required by the slender cylinder pressure sensor; the specific solution is as follows:

[0005] A method for processing a slender, thin-walled sleeve, the method comprising the following steps:

[0006] Step 1: Fix the sleeve body on the machine tool using a clamping and lifting method, and machine the outer circle of the first part of the sleeve body; the straight length of the first part is 150-200mm, the wall thickness is ≥1mm, and the length-to-diameter ratio is 15-20; the outer circle of the first part is respectively machined by semi-finishing, finishing and fine machining.

[0007] Step 2: Rotate the sleeve body for a second clamping and machine the second outer diameter of the sleeve body;

[0008] Step 3: Clamp the excess material at one end of the sleeve head and machine the outer diameter of the sleeve head;

[0009] Step 4: Sequentially machine the first bottom hole, the first internal thread hole, the first sealing surface, the second bottom hole, and the first end face of the sleeve head; the first bottom hole and the second bottom hole are located at both ends of the sleeve head, respectively;

[0010] Step 5: Machin the first external thread and the relief groove on the sleeve head in sequence;

[0011] Step 6: Insert the second part of the sleeve body into the second bottom hole of the sleeve head and fix it by laser welding.

[0012] Optionally, step 4 specifically includes:

[0013] The first flat-bottom drill is used to machine the bottom hole of the first internal thread hole, wherein the outer diameter of the first flat-bottom drill is smaller than the inner diameter of the bottom hole of the first internal thread hole;

[0014] The bottom hole of the first internal threaded hole is machined again using a second flat-bottom drill; wherein, the outer diameter of the second flat-bottom drill is the same as the inner diameter of the bottom hole of the first internal threaded hole;

[0015] The bottom hole of the first internal thread hole and the first sealing surface are machined sequentially using a first milling cutter with the same outer diameter as the second flat bottom drill.

[0016] After the first internal thread hole is machined, the first milling cutter is switched to the third flat bottom drill to machine the second bottom hole and the first end face in sequence;

[0017] Switch the third flat bottom drill to the second end mill to machine the second bottom hole and the first end face again.

[0018] Optionally, step 5 specifically includes:

[0019] The outer diameter of the first external thread is machined using the first grooving cutter;

[0020] The relief groove is machined using a second grooving tool;

[0021] The first external thread is machined using an external thread cutter.

[0022] A thin-walled sleeve is provided, using the aforementioned slender thin-walled sleeve processing method; the thin-walled sleeve has a hollow structure; the thin-walled sleeve includes a sleeve body and a sleeve head welded and fixed to the sleeve body; the sleeve body includes an integrally connected first part and a second part; the sleeve head includes a transition part and a threaded part fixedly connected to the transition part;

[0023] The transition section is provided with a second bottom hole for accommodating the second section; the bottom surface of the second bottom hole is a first end face; a first internal thread hole is provided at the bottom center of the second bottom hole; the bottom surface of the first internal thread hole is a first sealing surface; a first bottom hole is provided at the bottom of the first internal thread hole.

[0024] The outer surface of the threaded portion is provided with a first external thread, and a relief groove is provided on the side of the first external thread near the transition portion.

[0025] Optionally, the straight length of the first part is 150-200mm, the wall thickness is ≥1mm, and the length-to-diameter ratio is 15-20; the diameter of the first part is larger than the diameter of the second part.

[0026] Optionally, the second part and the second bottom hole are transition fit, and the two are fixed by laser welding.

[0027] An open sleeve is used to clamp the thin-walled sleeve; the open sleeve includes: a sleeve body; a receiving cavity for accommodating a first part is provided in the middle of the sleeve body; a second part extends out of the receiving cavity; a first annular limiting member is provided at one end of the sleeve body to restrict the movement of the first part, and an outer limiting boss for cooperating with the claw limiting is provided at the other end of the sleeve body; an elastic notch is provided on the side wall of the sleeve body.

[0028] A jaw structure for clamping the open sleeve; the jaw structure includes: a plurality of jaws slidably connected to a lathe chuck; the jaws are provided with fixing holes; the front end of the jaws is provided with an arc-shaped clamping part that contacts the open sleeve; wherein the arc of the arc-shaped clamping part is adapted to the outer circumferential arc of the open sleeve.

[0029] Optionally, the total arc length of the plurality of said arc-shaped clamping parts is 75%-80% of the radial circumference of the open sleeve; the length of the jaw is 1 / 3-1 / 2 of the length of the open sleeve.

[0030] An external threading tool is used to process the thin-walled sleeve; the external threading tool includes: a tool body and a cutting edge disposed at the front end of the tool body; characterized in that a clearance portion connected to the tool body is provided at the bottom of the cutting edge.

[0031] Compared with the prior art, the beneficial effects of the present invention are:

[0032] This invention provides a method for processing a slender, thin-walled sleeve, a thin-walled sleeve, and an open sleeve. By employing a split processing method, the sleeve body and sleeve head are processed separately. The sleeve body undergoes a three-stage processing method to ensure its straightness meets design requirements. Furthermore, this slender, thin-walled sleeve processing method avoids the technical problem of the first sealing surface not being perpendicular to the axial center of the first internal threaded hole, which could lead to poor sealing between the cylinder pressure sensor sealing end face and the first sealing surface, resulting in damage to the cylinder pressure sensor. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the overall structure of the sleeve body;

[0034] Figure 2 This is a schematic diagram of the overall structure of the sleeve head;

[0035] Figure 3 A schematic diagram of the overall structure of the sleeve head from another angle;

[0036] Figure 4 A structural diagram of the machining process for the sleeve head;

[0037] Figure 5 This is a schematic diagram of the structure of the open sleeve;

[0038] Figure 6 This is a schematic diagram of the structure of one of the chuck claws;

[0039] Figure 7 A schematic diagram of the second part of machining when the jaw structure clamps the open sleeve;

[0040] Figure 8 A schematic diagram of the machining process for clamping the sleeve head with a chuck structure;

[0041] Figure 9 This is a schematic diagram of the structure of an external threading tool;

[0042] Figure 10 This is a schematic diagram of the sleeve body being installed in the tool fixture. Detailed Implementation

[0043] To make the purpose, technical solution, and advantages of this application clearer, the following will be described in conjunction with the appendix. Figure 1-10 This application will be described in further detail. It is obvious that the described embodiments are merely some, not all, of the embodiments described herein. All other embodiments obtained by those skilled in the art based on the embodiments described herein without inventive effort are within the scope of protection of this application.

[0044] It should be understood that although the terms first, second, third, etc., may be used in the embodiments of this application, these descriptions should not be limited to these terms. These terms are only used to distinguish the descriptions. For example, first may also be referred to as second without departing from the scope of the embodiments of this application, and similarly, second may also be referred to as first.

[0045] To facilitate understanding of the slender thin-walled sleeve processing method, thin-walled sleeve, and open sleeve provided by this invention, the purpose of its application is first explained. Existing cylinder pressure sensor sleeves generally have a total length of 210mm and a wall thickness of 1mm. The straightness requirement on the outer side of the product is extremely high, requiring 0.02mm. The processing is extremely difficult, and clamping is challenging, easily causing product deformation and resulting in product scrap. Secondly, the precision parts requiring machining of the inner hole of existing thin-walled sleeves are located between 199.5-207.5mm in cavity depth. Conventional cutting tools cannot machine these precision parts at this depth, and currently, the process mainly relies on external imports.

[0046] It should be noted that the thin-walled sleeve has a hollow structure, meaning that the central hole inside the workpiece does not need to be machined. Only the outer circle of the thin-walled sleeve needs to be machined to ensure that the straightness of the outer side of the thin-walled sleeve meets the design requirements. Furthermore, the length of the workpiece is 30mm greater than the design size of the thin-walled sleeve to facilitate clamping.

[0047] The reference numerals in the figure are as follows: 1. Sleeve body; 11. First part; 12. Second part; 2. Sleeve head; 21. Transition part; 210. Second bottom hole; 211. First end face; 212. First internal threaded hole; 213. First sealing surface; 214. First bottom hole; 22. Threaded part; 220. Relief groove; 221. First external thread; 3. Sleeve body; 31. First annular limiting member; 32. External limiting boss; 33. Elastic notch; 4. Claw; 41. Fixing hole; 42. Arc-shaped clamping part; 5. Tool body; 51. Blade; 52. Clearance part; 6. Tooling fixture.

[0048] This application provides a method for machining a slender, thin-walled sleeve using a split-processing method; the thin-walled sleeve includes a sleeve body and a sleeve head welded and fixed to the sleeve body; the method includes the following steps:

[0049] Step 1: Fix the sleeve body on the machine tool using a clamping and lifting method, and machine the outer circle of the first part of the sleeve body; the straight length of the first part is 200mm, the wall thickness is 1mm, the outer diameter is 10mm, and the length-to-diameter ratio is 20; wherein, the outer circle of the first part is respectively semi-finished, finished and finely machined.

[0050] It is understood that the semi-finishing parameters are: spindle speed 500 rpm, depth of cut 0.1 mm, and feed rate 0.1 mm per rpm; the finishing parameters are: spindle speed 500 rpm, depth of cut 0.05 mm, and feed rate 0.1 mm per rpm; and the fine machining parameters are: spindle speed 300 rpm, feed rate 0.07 mm per rpm, and depth of cut 0.05 mm. The tailstock center pressure is adjusted to 3 bar. The advantages of this design are: excessive tailstock pressure leads to bending and deformation of the part, while insufficient pressure results in insufficient jacking force and vibration of the sleeve body; secondly, to prevent chips from entangled on the sleeve body during machining, an axial feed and radial lifting chip-breaking machining program is adopted, improving machining stability.

[0051] Step 2: Turn the sleeve body around and clamp the first part of the sleeve body in the open sleeve for a second clamping. Then, process the outer circle of the second part of the sleeve body. The second part extends 5mm out of the open sleeve, and the outer circle diameter of the second part is smaller than that of the first part.

[0052] Specifically, during processing, the remaining material portion of the sleeve body to be processed is first clamped using lathe chucks, wherein the remaining material portion of the sleeve body to be processed is located on the side near the second part; the other end of the sleeve body to be processed is clamped by the lathe tailstock. Then, the outer diameter of the first part is completed by finishing, semi-finishing and fine machining in sequence, wherein the length of the first part is 195mm, the inner diameter is 8mm, the outer diameter is 10mm and the wall thickness is 1mm; then, the sleeve body is turned around and the first part is inserted into the open sleeve, and the first part in the open sleeve is clamped by the chuck structure to cut off the remaining material portion, and the second part is processed; wherein the second part is located between the remaining material portion and the first part; the length of the second part is 5mm, the outer diameter is 9mm and the inner diameter is 8mm.

[0053] Step 3: Clamp the excess material at one end of the sleeve head and machine the outer diameter of the sleeve head, wherein the outer diameter of the sleeve head is 10mm.

[0054] Step 4: Sequentially machine the first bottom hole, the first internal thread hole, the first sealing surface, the second bottom hole, and the first end face of the sleeve head; the first bottom hole and the second bottom hole are located at both ends of the sleeve head, and the diameter of the first bottom hole is smaller than the diameter of the second bottom hole.

[0055] In this embodiment, the diameter of the first bottom hole is 2.5mm; the first internal thread hole is M5 specification and the hole depth is 7mm; the diameter of the second bottom hole 210 is 9mm and the hole depth is 4.5mm.

[0056] Specifically,

[0057] Step 1: Use a 2mm A2 center drill to machine the center of the first pilot hole, which facilitates precise positioning of the center of the first pilot hole. Then, use a 2.5mm taper drill to machine the first pilot hole.

[0058] Step 2: Use a 4mm-4.4mm flat-bottom drill bit to machine the pilot hole of the first internal threaded hole. Preferably, the diameter of the first flat-bottom drill bit is 4.4mm. The inner diameter of the pilot hole of the first internal threaded hole is 4.5mm. The advantages of this step are that the pilot hole of the first internal threaded hole is initially machined by the first flat-bottom drill bit, which ensures the perpendicularity of the first internal threaded hole and facilitates subsequent milling cutter finishing, thus preventing milling cutter wear.

[0059] Step 3: Use a 4.5mm second flat-bottom drill to re-machine the bottom hole of the first internal thread hole; the purpose of this design is to perform secondary machining on the bottom hole of the first internal thread hole to improve the perpendicularity of the bottom hole of the first internal thread hole, and at the same time facilitate the subsequent milling cutter finishing; the machining parameters of the 4.5mm second flat-bottom drill are a rotation speed of 500 revolutions per minute and a feed of 0.15mm per revolution.

[0060] Step 4: Use a 4.5mm first milling cutter to finish machine the bottom hole of the first internal thread hole and the first sealing surface, thereby ensuring that the perpendicularity between the axial direction of the first internal thread hole and the end face of the first bottom hole meets the design requirements and avoids technical problems of poor sealing. Then, tap the first internal thread hole. The machining parameters of the 4.5mm first milling cutter are a rotation speed of 1500 revolutions per minute and a pause time of 0.5 seconds, thereby ensuring the technical requirements of the first sealing surface roughness Ra0.8 and flatness of 0.01mm, which meets the airtightness requirements of the product.

[0061] In this step, the bottom surface of the first internal threaded hole serves as the first sealing surface for the cylinder pressure sensor, and it is also the upper end surface of the first bottom hole. The first sealing surface is an annular surface with a width of 1 mm. Specifically, the cylinder pressure sensor sleeve needs to be installed in the engine cylinder block, and the cylinder pressure is monitored by the cylinder pressure sensor. Due to the high temperature and high pressure gas generated inside the combustion chamber, threadlocker cannot be used at the connection between the cylinder pressure sensor and the first internal threaded hole. Therefore, sealing is achieved by the front end of the cylinder pressure sensor contacting the first sealing surface. However, in existing processing methods, the radial width of the first sealing surface on one side is only 1 mm, and the perpendicularity of the radial direction of the first sealing surface to the axial direction of the first internal threaded hole cannot be guaranteed. This results in a poor seal between the cylinder pressure sensor and the first sealing surface, causing the cylinder pressure sensor to be damaged and unusable.

[0062] This application overcomes the technical problem that the radial surface of the bottom surface (first sealing surface) of the first internal threaded hole is not perpendicular to the central axis of the first internal threaded hole by using a first flat-bottom drill and a second flat-bottom drill to perform secondary machining on the bottom hole of the first internal threaded hole, and at the same time using a first milling cutter to perform finishing machining on the bottom hole of the first internal threaded hole.

[0063] It is understood that this application performs two roughing operations on the bottom hole of the first internal threaded hole using a first flat-bottom drill and a second flat-bottom drill, and then performs a finishing operation on the bottom hole of the first internal threaded hole using a first milling cutter, thereby ensuring that the axial center line of the bottom hole of the first internal threaded hole is perpendicular to the radial center line of the first sealing surface, thereby achieving the sealing effect of the cylinder pressure sensor.

[0064] Step 5: After the first internal thread hole is machined, the first milling cutter is switched to the third flat-bottom drill to machine the second bottom hole and the first end face in sequence; wherein, the difference between the inner diameter of the second bottom hole and the outer diameter of the sleeve head is 1mm; in this embodiment, the inner diameter of the second bottom hole is 9mm; in this step, the first milling cutter with an outer diameter of 4.5mm is switched to the third flat-bottom drill with an outer diameter of 4.5mm to perform rough machining on the second bottom hole and the first end face, and then the second milling cutter with an outer diameter of 6mm is switched to machine the second bottom hole with an inner diameter of 9mm and the first end face; the advantage of this design is that it ensures the perpendicularity between the axial direction of the second bottom hole and the radial direction of the first end face; furthermore, since the second bottom hole is used to fit and insert with the second part, and the sleeve body and the sleeve head are fixed by laser welding, once the radial direction of the first end face and the axial direction of the second bottom hole are machined in an inclination, it will affect the overall perpendicularity of the thin-walled sleeve. In this application, the innovative use of milling cutter turning method ensures the machining accuracy of the second bottom hole and the first end face, thereby improving the yield of parts.

[0065] Step 5: Sequentially machine the first external thread and the relief groove on the sleeve head; wherein, the first external thread is M8; the width of the relief groove is 1.5mm and the outer diameter is 7mm.

[0066] Specifically, step 5 includes: using a first grooving cutter to initially machine the outer diameter of the first external thread; using a second grooving cutter to machine the relief groove, and then using an external threading cutter to machine the first external thread; this application avoids the technical problem of interference between the external threading cutter and the relief groove when machining the first external thread by modifying the external threading cutter.

[0067] Step 6: Insert the second part of the sleeve body into the second bottom hole of the sleeve head and fix it by laser welding.

[0068] It is understandable that this application optimizes the machining process by combining the sleeve head with an improved external threading tool, which can complete all machining in one clamping, ensuring machining accuracy while enabling subsequent mass production.

[0069] Specifically, the second part and the second bottom hole are in a transition fit mode. First, the sleeve body and the sleeve head are pressed by a press. Then, in order to accurately control the welding point position of the sleeve body and the sleeve head, one end of the sleeve body is installed in the tooling fixture. The sleeve body and the tooling fixture adopt a clearance fit, thereby playing a limiting role and achieving consistency in batch welding.

[0070] It is understood that this application employs a slender, thin-walled sleeve processing method, and uses split processing to ensure that the straightness of the sleeve body meets the design requirements and that the first sealing surface is perpendicular to the first internal threaded hole, thereby ensuring that the sealing end face of the cylinder pressure sensor contacts the first sealing surface to achieve a sealing effect and avoiding damage to the cylinder pressure sensor.

[0071] On the other hand, this application provides a thin-walled sleeve using the aforementioned slender thin-walled sleeve processing method; the thin-walled sleeve has a hollow structure; the thin-walled sleeve includes a sleeve body and a sleeve head welded and fixed to the sleeve body; the sleeve body includes an integrally connected first part and a second part; the sleeve head includes a transition part and a threaded part fixedly connected to the transition part;

[0072] The transition section is provided with a second bottom hole for accommodating the second section; the bottom surface of the second bottom hole is a first end face; a first internal thread hole is provided at the bottom center of the second bottom hole; the bottom surface of the first internal thread hole is a first sealing surface; a first bottom hole is provided at the bottom center of the first internal thread hole.

[0073] The outer surface of the threaded portion is provided with a first external thread, and a relief groove is provided on the side of the first external thread near the transition portion.

[0074] Optionally, the first part has a straight length of 200mm, a wall thickness of 1mm, and a length-to-diameter ratio of 20; the second part has an outer diameter of 9mm, a wall thickness of 0.5mm, and a length of 5mm; the second part and the second bottom hole are transition fit, and the two are fixed by laser welding.

[0075] On the other hand, this application provides an open sleeve for clamping the thin-walled sleeve; the open sleeve includes: a sleeve body; the sleeve body has a receiving cavity in the middle for clamping the first part; the second part extends out of the receiving cavity; one end of the sleeve body is provided with a first annular limiting member to restrict the movement of the first part, and the other end of the sleeve body is provided with an outer limiting boss that cooperates with the claw limiting; the side wall of the sleeve body is provided with an elastic notch; wherein, one side of the first annular limiting member is provided with an opening communicating with the elastic notch.

[0076] On the other hand, this application provides a jaw structure for clamping the open sleeve; the jaw structure includes: three jaws that are slidably connected to a lathe chuck; the jaws are provided with fixing holes, and the jaws are screwed to the chuck by bolts passing through the fixing holes; the front end of the jaws is provided with an arc-shaped clamping part that contacts the open sleeve; wherein the arc of the arc-shaped clamping part is adapted to the outer circumferential arc of the open sleeve.

[0077] Optionally, the total arc length of the three arc-shaped clamping parts is 80% of the radial circumference of the open sleeve; the length of the claw is 1 / 2 of the length of the open sleeve. The advantage of this design is that only a small force is needed to clamp the first part of the sleeve body, and the open sleeve will not deform due to excessive squeezing force during the clamping process.

[0078] On the other hand, this application provides an external threading tool for machining the thin-walled sleeve; the external threading tool includes: a tool body and a cutting edge disposed on one side of the front end of the tool body; the bottom of the cutting edge is provided with a clearance portion connected to the tool body.

[0079] Exemplary embodiments according to this application will now be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. It should be understood that these embodiments are provided so that the disclosure of this application is thorough and complete, and that the concept of these exemplary embodiments is fully conveyed to those skilled in the art. In the drawings, for clarity, the thickness of layers and regions may be exaggerated, and the same reference numerals are used to denote the same devices, and therefore their description will be omitted.

Claims

1. A method for processing a slender, thin-walled sleeve, characterized in that, The method includes the following steps: Step 1: Fix the sleeve body (10) on the machine tool using a clamping and lifting method, and process the outer circle of the first part (11) of the sleeve body (10); the straight length of the first part (11) is 150-200mm, the wall thickness is ≥1mm, and the length-to-diameter ratio is 15-20; wherein, the outer circle of the first part (11) is respectively semi-finished, finished and finely finished; Step 2: Rotate the sleeve body (10) for a second clamping and process the outer circle of the second part (12) of the sleeve body (10); Step 3: Clamp the excess material at one end of the sleeve head (2) and machine the outer circle of the sleeve head (2); Step 4: Sequentially machine the first bottom hole (214), the first internal thread hole (212), the first sealing surface (213), the second bottom hole (210), and the first end face (211) of the sleeve head (2); the first bottom hole (214) and the second bottom hole (210) are located at both ends of the sleeve head (2); Step 5: Machin the first external thread (221) and the relief groove (220) of the sleeve head (2) in sequence; Step 6: Insert the second part (12) of the sleeve body (10) into the second bottom hole (210) of the sleeve head (2) and fix it by laser welding.

2. The method according to claim 1, characterized in that, Step 4 specifically includes: The first flat-bottom drill is used to machine the bottom hole of the first internal thread hole (212), wherein the outer diameter of the first flat-bottom drill is smaller than the inner diameter of the bottom hole of the first internal thread hole (212); The bottom hole of the first internal thread hole (212) is machined again using a second flat-bottom drill; wherein the outer diameter of the second flat-bottom drill is the same as the inner diameter of the bottom hole of the first internal thread hole (212); The bottom hole of the first internal thread hole (212) and the first sealing surface (213) are machined sequentially using a first milling cutter with the same outer diameter as the second flat bottom drill. After the first internal thread hole (212) is machined, the first milling cutter is switched to the third flat bottom drill to machine the second bottom hole (210) and the first end face (211) in sequence; Switch the third flat bottom drill to the second end mill to machine the second bottom hole (210) and the first end face (211) again.

3. The method according to claim 2, characterized in that, Step 5 specifically includes: The outer diameter of the first external thread (221) is machined using the first grooving cutter; The relief groove (220) is machined using the second grooving tool; The first external thread (221) is machined using an external thread cutter.

4. A thin-walled sleeve, characterized in that, The method for processing a slender thin-walled sleeve according to any one of claims 1-3 is adopted; the thin-walled sleeve has a hollow structure; the thin-walled sleeve includes a sleeve body (10) and a sleeve head (2) welded and fixed to the sleeve body (10); the sleeve body (10) includes a first part (11) and a second part (12) integrally connected; the sleeve head (2) includes a transition part (21) and a threaded part (22) fixedly connected to the transition part (21); The transition portion (21) is provided with a second bottom hole (210) for accommodating the second portion (12); the bottom surface of the second bottom hole (210) is a first end face (211); a first internal thread hole (212) is provided at the bottom center of the second bottom hole (210); the bottom surface of the first internal thread hole (212) is a first sealing surface (213); a first bottom hole (214) is provided at the bottom of the first internal thread hole (212); The outer surface of the threaded portion (22) is provided with a first external thread (221), and a relief groove (220) is provided on the side of the first external thread (221) near the transition portion (21).

5. The thin-walled sleeve according to claim 4, characterized in that, The first part (11) has a straight length of 150-200mm, a wall thickness of ≥1mm, and a length-to-diameter ratio of 15-20; the diameter of the first part (11) is greater than the diameter of the second part (12).

6. The thin-walled sleeve according to claim 5, characterized in that, The second part (12) and the second bottom hole (210) are in transition fit, and the two are fixed by laser welding.

7. An open sleeve, characterized in that, For clamping the thin-walled sleeve according to any one of claims 4-6; the open sleeve includes: a sleeve body (3); the sleeve body (3) is provided with a receiving cavity in the middle for receiving the first part (11); the second part (12) extends out of the receiving cavity; one end of the sleeve body (3) is provided with a first annular limiting member (31) for restricting the movement of the first part (11), and the other end of the sleeve body (3) is provided with an outer limiting boss (32) for limiting with a pawl (4); the side wall of the sleeve body (3) is provided with an elastic notch (33).

8. A claw structure, characterized in that, Used to clamp the open sleeve as described in claim 7; the jaw structure includes: a plurality of jaws (4) slidably connected to the lathe chuck; the jaws (4) are provided with fixing holes (41); the front end of the jaws (4) is provided with an arc-shaped clamping part (42) that contacts the open sleeve; wherein the arc of the arc-shaped clamping part (42) is adapted to the outer circumferential arc of the open sleeve.

9. The claw structure according to claim 8, characterized in that, The total arc length of the plurality of said arc-shaped clamping parts (42) is 75%-80% of the radial circumference of the open sleeve; the length of the claw is 1 / 3-1 / 2 of the length of the open sleeve.

10. An external threading tool for machining the thin-walled sleeve according to any one of claims 4-6; the external threading tool comprising: The blade body (5) and the blade (51) disposed at the front end of the blade body (5); characterized in that the bottom of the blade (51) is provided with a clearance part (52) connected to the blade body (5).

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