Mandrel machining process

Abstract

The invention provides a mandrel machining process which comprises the following steps: S101, hermetically connecting the end surface of a first pipe section and one end surface of a connecting sleeve by adopting a welding process to form a reference section; s102, carrying out material removal processing on the reference section so as to enable the radial run-out of the outer circle of the reference section and the perpendicularity between the other end face of the connecting sleeve and the axis direction of the reference section to meet a first preset requirement; s103, the second pipe section and the connecting sleeve are fixed through spot welding, and radial run-out of the second pipe section is detected with the reference section as the reference; s104, if the radial run-out of the second pipe section meets a second preset requirement, the next step is carried out, and if the radial run-out of the second pipe section does not meet the second preset requirement, a spot welding fixing point between the second pipe section and the connecting sleeve is removed, the relative position of the second pipe section and the connecting sleeve is adjusted, and the step S103 is repeated till the second preset requirement is met; s105, adopting a welding process to hermetically connect different components of the mandrel fixed by spot welding; therefore, the radial run-out of the mandrel after welding can be effectively reduced.

Description

Technical Field

[0001] The present application relates to the technical field of air compressors, and in particular to a core shaft processing technology. Background Art

[0002] The rotor core shaft is a load-bearing component that rotates at high speed in the compressor and is used to generate high-pressure air. Due to its structure, it is lightweight, has high requirements for yield strength and bearing capacity, and as a core component in the compressor, it also has extremely strict requirements for product precision.

[0003] In the related art, the rotor core shaft is composed of multiple sections of thin-walled pipes, and the ends of the multiple sections of thin-walled pipes are welded and connected. This structure and connection method cause the rotor core shaft to be easily scrapped due to large radial runout during the processing and forming process, which not only affects the processing efficiency but also increases the processing cost. Summary of the invention

[0004] In view of this, the present application provides a core shaft processing process, which can effectively reduce the radial runout of the core shaft after welding is completed by adjusting the processing order of different components of the core shaft, thereby reducing the probability of the core shaft being scrapped due to large radial runout during the processing and forming process, thereby improving processing efficiency and reducing costs.

[0005] In order to achieve the above objectives, this application provides the following technical solutions:

[0006] A core shaft processing technology, the core shaft comprises a first pipe segment and a second pipe segment, and the first pipe segment and the second pipe segment are connected by a connecting sleeve, and the core shaft processing technology comprises the following steps:

[0007] S101, using a welding process to seal and connect an end surface of the first pipe segment and an end surface of the connecting sleeve to form a reference segment;

[0008] S102, performing material removal processing on the reference segment so that the radial runout of the outer circle of the reference segment and the perpendicularity between the other end surface of the connecting sleeve and the axial direction of the reference segment meet a first preset requirement;

[0009] S103, fixing the second pipe segment and the connecting sleeve by spot welding, and detecting the radial runout of the second pipe segment with the reference segment as a reference;

[0010] S104, if the radial runout of the second pipe segment meets the second preset requirement, proceed to the next step; if the radial runout of the second pipe segment does not meet the second preset requirement, remove the spot welding fixing point between the second pipe segment and the connecting sleeve, adjust the relative position of the second pipe segment and the connecting sleeve, and repeat step S103 until the radial runout of the second pipe segment meets the second preset requirement;

[0011] S105, using a welding process to seal and connect different components of the core shaft fixed by spot welding.

[0012] Optionally, the mandrel further includes a journal section, and the journal section is welded to an end surface of the second pipe section away from the connecting sleeve, and the following steps are further included between step S104 and step S105:

[0013] S201, fix the second pipe segment and the shaft neck segment by spot welding, and detect the radial runout of the shaft neck segment with the reference segment as the reference,

[0014] S202. If the radial runout of the shaft neck segment meets the third preset requirement, proceed to the next step. If the radial runout of the shaft neck segment does not meet the third preset requirement, remove the spot welding fixing points between the second pipe segment and the shaft neck segment, adjust the relative position of the second pipe segment and the shaft neck segment, and repeat step S201 until the radial runout of the shaft neck segment meets the third preset requirement.

[0015] Optionally, after step S105, the mandrel is straightened by using a V-shaped tool, the V-shaped tool comprising a base provided with a V-shaped groove and a pressure ring that can be connected to the base, and straightening the mandrel by using the V-shaped tool comprises the following steps:

[0016] S106, using the first pipe segment and the second pipe segment as references respectively, detecting radial runout at each position of the mandrel, and marking positions on the mandrel where radial runout exceeds a first threshold range;

[0017] S107, placing the mandrel in the V-shaped groove, and measuring the height of the top of the mandrel from the table of the base, and the measuring position is the position where the radial runout marked on the mandrel exceeds the first threshold range;

[0018] S108, setting the pressure ring at a position where the measurement result is greater than a second threshold range, and setting a gasket at a position where the measurement result is less than the second threshold range;

[0019] S109, re-measure the height of the top of the mandrel from the table of the base, and the measurement position is consistent with step S107;

[0020] S110, calculating the height difference of different measuring positions, if the height difference meets the fourth preset requirement, proceeding to the next step, if the height difference does not meet the fourth preset requirement, repeating steps S108 and S109 until the height difference meets the fourth preset requirement;

[0021] S111, placing the V-shaped tooling with the mandrel fixed thereon in a stress relief furnace, removing the welding stress of the mandrel at high temperature, and straightening the mandrel.

[0022] Optionally, an airtightness detection process is further included, and the airtightness detection process includes the following steps:

[0023] S112, sealing one end surface of the mandrel and the through hole on the circumferential side surface of the mandrel;

[0024] S113, sealingly connecting the other end of the mandrel to a hydraulic press, using the hydraulic press to increase the internal pressure of the mandrel to a preset pressure, and maintaining the preset pressure;

[0025] S114, observing whether there is leakage at the weld position, and if there is no leakage at the weld position within a preset time period, the welding air tightness of the weld position meets the requirements.

[0026] Optionally, a spline tooth is provided on the outer circumference of the mandrel, and the mandrel is provided with a first protrusion for fixing a gear shaping tool, and the processing steps of the spline tooth are as follows:

[0027] S115, sleeve a gear shaping tool on the position of the mandrel where the first protrusion is provided, and fix the gear shaping tool;

[0028] S116, fixing the mandrel on the gear shaping workbench, and making the end surface of the gear shaping tool fit with the corresponding plane of the gear shaping workbench;

[0029] S117, using a gear shaping device to process spline teeth at corresponding positions of the mandrel.

[0030] Optionally, in step S101, the first pipe section and the connecting sleeve are both assembled on a first welding tool;

[0031] The first welding tool includes a support rod and a locking plug. The support rod axially penetrates the first pipe section and the connecting sleeve and is threadedly connected to the locking plug to form an axial limit groove on the circumferential outer side of the first welding tool. The axial limit groove can limit the movement of the first pipe section and the connecting sleeve in the axial direction, and the gap between the support rod and the first pipe section ranges from 0.05mm to 0.1mm.

[0032] Optionally, the following steps are further included between step S101 and step S102:

[0033] S301, placing the reference segment after welding in a stress relief furnace to remove welding stress.

[0034] Optionally, the circumferential side surface of the mandrel has a through hole, and along the axial direction of the mandrel, second protrusions are provided on both sides of the through hole, and the step of blocking the through hole on the circumferential side surface of the mandrel is:

[0035] S401, processing a sealing groove around the outer circumference of the second protrusion, and disposing a sealing ring inside the sealing groove;

[0036] S402, sleeve a sealing ring on the core shaft, and make the sealing ring and the second protrusions on both sides of the through hole sealed and connected through the sealing ring.

[0037] Optionally, the following steps are also included:

[0038] S118, finishing turning the outer circumference of the mandrel, and reserving a finishing allowance of 0.15 mm to 0.2 mm;

[0039] S119, fine grinding the dimensions from the circumferential outer side of the mandrel to each position of the mandrel to meet the fifth preset requirement.

[0040] Optionally, in step S115, a fitting clearance between the gear inserting tool and the first protrusion is less than 0.02 mm.

[0041] The present application provides a mandrel processing process that completes the welding process of the mandrel in multiple times, and after the first welding forms the reference section, the reference section is subjected to material removal processing to remove or reduce the deformation of the different components in the reference section caused by factors such as welding heat input in the first welding. In this way, the accumulation of deformation caused by multiple welding after subsequent welding can be avoided, thereby effectively reducing the radial runout of the mandrel after welding is completed. In addition, before performing step S105, the reference section is fixed to other components in the mandrel by spot welding. This setting method can effectively avoid the large post-weld runout caused by the movement of the reference section and / or other components in the mandrel during the welding process, and the above-mentioned spot welding constraints can also reduce the deformation caused by the shrinkage of the weld position during sealing welding to a certain extent, thereby further reducing the radial runout of the mandrel after welding. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0043] Figure 1 This is a schematic structural diagram of a rotor core shaft in an embodiment of the present application;

[0044] Figure 2 A schematic diagram of a structure in which a reference section provided in an embodiment of the present application is assembled on a first welding tool;

[0045] Figure 3A structural schematic diagram of a reference section after welding is provided for an embodiment of the present application;

[0046] Figure 4 A structural schematic diagram of assembling a rotor core shaft to a second welding tool is provided for an embodiment of the present application;

[0047] Figure 5 A schematic diagram of a structure for assembling a rotor core shaft on a V-shaped tooling provided in an embodiment of the present application;

[0048] Figure 6 A schematic structural diagram of a mandrel with a sealing groove provided in an embodiment of the present application;

[0049] Figure 7 A schematic structural diagram of a mandrel equipped with a gear shaping tool provided in an embodiment of the present application.

[0050] exist Figure 1-Figure 7 middle:

[0051] 1-oil distribution sleeve, 2-front axle assembly, 3-pull rod front journal, 4-front core shaft, 5-core shaft connecting sleeve, 6-core shaft rear journal, 7-core shaft front journal, 8-front pull rod, 9-rear core shaft, 10-locking plug, 11-support rod, 12-first axial fixing part, 13-second axial fixing part, 14-threaded rod, 15-rotor core shaft, 16-pressure ring, 17-base, 18-sealing groove, 19-gear tooling, 20-screws, 21-first fine-ground plug, 22-second fine-ground plug. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0053] An embodiment of the present application discloses a core shaft processing process, which is suitable for a core shaft that includes at least a first pipe segment and a second pipe segment, and the first pipe segment and the second pipe segment are connected by a connecting sleeve. The core shaft processing process is particularly suitable for scenarios where the axial dimensions of the first pipe segment and the second pipe segment are large and the wall thickness of the first pipe segment and the second pipe segment is thin.

[0054] The mandrel processing process in the embodiment of the present application includes the following steps:

[0055] S101. Use a welding process to seal and connect the end face of the first pipe section and one end face of the connecting sleeve to form a reference section. The above welding process can be adaptively designed as needed during specific implementation. This application does not make specific limitations. For example, the above welding process can be vacuum electron beam welding. During the welding process, the first pipe section and the connecting sleeve are both assembled on the first welding fixture. The first welding fixture includes a support rod and a locking plug. The support rod axially penetrates the first pipe section and the connecting sleeve, and is threadedly connected to the locking plug to form an axial limit groove on the outer side of the circumference of the first welding fixture. The axial limit groove can limit the movement of the first pipe section and the connecting sleeve in the axial direction, and the gap between the support rod and the first pipe section ranges from 0.05mm to 0.1mm. In this way, the first welding fixture is used to avoid axial movement and radial deformation of the first pipe section and the connecting sleeve during welding.

[0056] S102, the reference segment is processed by material removal (i.e., the reference segment is processed by removing material, which can be lathe processing, for example), so that the radial runout of the outer circle of the reference segment and the perpendicularity between the other end face of the connecting sleeve and the axis direction of the reference segment meet the first preset requirement; the first preset requirement here can be adaptively designed as needed during the specific implementation. Specifically, the stricter the first preset requirement, the higher the dimensional accuracy of the reference segment, and the more conducive it is to reduce the radial runout of the mandrel in the subsequent processing process; but this will also increase the processing difficulty of the reference segment. Based on this, in some exemplary embodiments, in order to ensure that the radial runout of the outer circle of the reference segment after processing and the perpendicularity between the other end face of the connecting sleeve and the axis direction of the reference segment meet the first preset requirement, before the material removal processing is performed, the radial runout of the reference part is first inspected, and only the reference segment with a radial runout less than 0.05mm is subjected to material removal processing, while the reference segment with a radial runout greater than 0.05mm is scrapped. Furthermore, the specific method of material removal processing is: clamp the middle section of the first pipe section, and process the outer circle of the connecting sleeve and its end face away from the first pipe section; after the processing is completed, take the outer circle of the connecting sleeve as the reference, process the inner hole and outer circle of the other end of the reference section (that is, the end of the first pipe section away from the connecting sleeve), and ensure that the coaxiality of the inner hole and outer circle with the outer circle of the connecting sleeve is 0.025mm.

[0057] S103, fixing the second pipe section and the connecting sleeve by spot welding, and detecting the radial runout of the second pipe section with the reference section as a reference;

[0058] S104. If the radial runout of the second pipe segment meets the second preset requirement, proceed to the next step. If the radial runout of the second pipe segment does not meet the second preset requirement, remove the spot welding fixing points between the second pipe segment and the connecting sleeve, adjust the relative positions of the second pipe segment and the connecting sleeve, and repeat step S103 until the radial runout of the second pipe segment meets the second preset requirement. The second preset requirement here can be adaptively designed as needed during specific implementation. Specifically, the stricter the second preset requirement, the smaller the radial runout after the core shaft is processed. However, this will also increase the difficulty of implementing this step.

[0059] S105. Using a welding process, seal and connect different components of the mandrel fixed by spot welding (the different components may include the second pipe section in this embodiment and the shaft neck section described below). Specifically, use a second welding tool to clamp both ends of the mandrel and place it in a vacuum environment, and use verified welding parameters to weld the weld seam in the mandrel except for the reference section.

[0060] As described above, the embodiment of the present application completes the welding process of the mandrel in multiple times, and after the first welding forms the reference section, the reference section is subjected to material removal processing to remove or reduce the deformation of different components in the reference section caused by factors such as welding heat input during the first welding. In this way, the accumulation of deformation caused by multiple welding after subsequent welding can be avoided, thereby effectively reducing the radial runout of the mandrel after welding is completed.

[0061] In addition, before performing step S105, the reference segment and other components in the core shaft are fixed by spot welding. This setting method can effectively avoid large post-weld runout caused by the movement of the reference segment and / or other components in the core shaft during the welding process, and the above-mentioned spot welding constraint can also reduce the deformation caused by the shrinkage of the weld position during sealing welding to a certain extent, thereby further reducing the radial runout of the core shaft after welding.

[0062] In some embodiments, the mandrel further includes a shaft neck section, and the shaft neck section is welded to the end surface of the second pipe section away from the connecting sleeve. In this case, the processing technology of the mandrel includes the following steps:

[0063] S101, using a welding process to seal and connect an end surface of the first pipe segment and an end surface of the connecting sleeve to form a reference segment;

[0064] S102, performing material removal processing on the reference segment so that the radial runout of the outer circle of the reference segment and the perpendicularity between the other end surface of the connecting sleeve and the axial direction of the reference segment meet the first preset requirement;

[0065] S103, fixing the second pipe section and the connecting sleeve by spot welding, and detecting the radial runout of the second pipe section with the reference section as a reference;

[0066] S104, if the radial runout of the second pipe segment meets the second preset requirement, proceed to the next step; if the radial runout of the second pipe segment does not meet the second preset requirement, remove the spot welding fixing point between the second pipe segment and the connecting sleeve, adjust the relative position of the second pipe segment and the connecting sleeve, and repeat step S103 until the radial runout of the second pipe segment meets the second preset requirement;

[0067] S201, fix the second pipe section and the shaft neck section by spot welding, and detect the radial runout of the shaft neck section with the reference section as the reference,

[0068] S202. If the radial runout of the shaft neck segment meets the third preset requirement, proceed to the next step. If the radial runout of the shaft neck segment does not meet the third preset requirement, remove the spot welding fixing points between the second pipe segment and the shaft neck segment, adjust the relative position of the second pipe segment and the shaft neck segment, and repeat step S201 until the radial runout of the shaft neck segment meets the third preset requirement.

[0069] S105. Use welding technology to seal and connect different components of the core shaft fixed by spot welding.

[0070] It should be noted that, in this embodiment, except for step S201 and step S202, the other steps are the same as above, so they are not repeated. In addition, the third preset requirement in step S202 can be adaptively designed as needed during implementation. Specifically, the stricter the third preset requirement, the smaller the radial runout after the mandrel is processed; but this will also increase the difficulty of implementing this step.

[0071] As mentioned above, in this embodiment, when performing the second sealing welding, in addition to completing the welding between the reference section and the second pipe section, it is also necessary to complete the welding between the second pipe section and the shaft neck section. Moreover, in this embodiment, after the second pipe section and the reference section, and the second pipe section and the shaft neck section are spot welded and fixed, the second sealing welding is performed. In this way, when the second sealing welding is completed in a vacuum environment, the number of times the core shaft repeatedly enters the vacuum environment during processing can be reduced, which is beneficial to improving processing efficiency and avoiding welding deformation caused thereby.

[0072] In some embodiments, after step S105, a V-shaped tool is further used to straighten the mandrel, wherein the V-shaped tool includes a base provided with a V-shaped groove and a pressure ring that can be connected to the base (the V-shaped tool can be specifically referred to Figure 5 ), using a V-type tool to straighten the mandrel includes the following steps:

[0073] S106, using the first pipe segment and the second pipe segment as references respectively, detecting radial runout at each position of the mandrel, and marking positions on the mandrel where the radial runout exceeds a first threshold range;

[0074] S107, placing the mandrel in the V-groove, and measuring the height of the top of the mandrel from the table of the base, and the measuring position is the position where the radial runout marked on the mandrel exceeds the first threshold range;

[0075] S108, setting a pressure ring at a position where the measurement result is greater than the second threshold range, and setting a gasket at a position where the measurement result is less than the second threshold range;

[0076] S109, re-measure the height of the top of the mandrel from the table of the base, and the measurement position is consistent with step S107;

[0077] S110, calculating the height difference between different measurement positions, and if the height difference meets the fourth preset requirement, proceeding to the next step, and if the height difference does not meet the fourth preset requirement, repeating steps S108 and S109 until the height difference meets the fourth preset requirement;

[0078] S111. Place the V-shaped fixture with the mandrel fixed thereon in a stress relief furnace, remove the welding stress of the mandrel at high temperature, and straighten the mandrel.

[0079] It should be noted that the first threshold range and the second threshold range mentioned above can be adaptively designed according to the accuracy requirements during the specific implementation process, and this application does not make any specific limitations on this.

[0080] Furthermore, in some embodiments, an airtightness detection process is also included, and the airtightness detection process includes the following steps:

[0081] S112, block one end face of the core shaft and the through hole on the circumferential side of the core shaft; it should be noted that, in some embodiments, the shaft neck section at one end of the core shaft can block one end face of the core shaft, in which case, there is no need to block the end face of the core shaft. In addition, in this step, the step of blocking the through hole on the circumferential side of the core shaft is as follows: S401, process a sealing groove around the circumferential outer side of the second protrusion, and set a sealing ring inside the sealing groove (the above-mentioned second protrusion is a structure reserved for blocking the through hole on the circumferential side of the core shaft during the processing of the core shaft, and it is set on both sides of the through hole along the axial direction of the core shaft); S402, set a sealing ring on the core shaft, and make the sealing ring and the second protrusions on both sides of the through hole sealed and connected through the sealing ring.

[0082] S113. The other end of the core shaft (i.e., the end that is not blocked) is sealed and connected to the hydraulic press. The hydraulic press is used to increase the internal pressure of the core shaft to a preset pressure and maintain the preset pressure. The preset pressure can be adaptively designed according to needs during specific implementation. It can be understood that during the specific implementation, the greater the preset pressure, the better the airtightness of the weld position that passes the inspection.

[0083] S114, observe whether there is leakage at the weld position, and if there is no leakage at the weld position within the preset time period, the welding air tightness at the weld position meets the requirements. The above preset time can be adaptively designed as needed during specific implementation, and can be 5 minutes, 6 minutes or 7 minutes, etc. It can be understood that during specific implementation, the longer the preset time is, the higher the reliability of the detection result is.

[0084] In addition, in some embodiments, a spline tooth is provided on the outer circumference of the mandrel, and the mandrel is provided with a first protrusion for fixing the gear shaping tooling, and the processing steps of the spline tooth are as follows:

[0085] S115, sleeve the gear shaping tool on the position of the core shaft where the first protrusion is provided, and fix the gear shaping tool, and the matching clearance between the gear shaping tool and the first protrusion is less than 0.02mm.

[0086] S116, fixing the mandrel on the gear shaping workbench, and making the end face of the gear shaping tool fit with the corresponding plane of the gear shaping workbench;

[0087] S117. Use gear shaping equipment to process spline teeth at corresponding positions of the core shaft.

[0088] As described above, this embodiment provides a gear shaping tool to avoid the gear shaping device being directly clamped on the core shaft during the gear shaping process, thereby effectively avoiding deformation caused by the gear shaping device during the spline tooth processing.

[0089] Furthermore, in some embodiments, the following steps are also included:

[0090] S118, fine turn the outer circumference of the mandrel and reserve a fine grinding allowance of 0.15mm-0.2mm;

[0091] S119. The dimensions from the outer circumference of the fine grinding mandrel to each position of the mandrel meet the fifth preset requirements (i.e., drawing requirements).

[0092] Furthermore, in some embodiments, in order to further improve the qualified rate of the mandrel after processing, the following steps are further included between step S101 and step S102:

[0093] S301, placing the welded reference segment in a stress relief furnace to remove welding stress.

[0094] S302. Weld inspection: Radiographic inspection of weld position, penetration depth, internal defects of welds and weld accuracy must meet GJB1718-93 Grade I weld standards.

[0095] S303, sequential fluorescence detection: detect welding defects such as cracks and slag inclusions on the outer surface of the weld.

[0096] S304, perform runout detection on the reference section formed in step S101, specifically, use the middle section of the former mandrel as the machining alignment reference, and align the entire section radial runout <0.05mm, thereby ensuring the coaxiality between the machining end and the non-machining end of the part. In this step, if the detection fails, the part will be scrapped.

[0097] Example:

[0098] For ease of understanding, the following Figure 1-Figure 7 , taking the processing of the rotor core shaft in the compressor as an example, the core shaft processing technology in the present application is exemplified.

[0099] The rotor core shaft 15 in this embodiment has a total length of about 800 mm, an outer diameter of about φ30 mm, and an aspect ratio of 23 times. The material of the rotor core shaft 15 is 1Cr11Ni2W2MoV; Figure 1 As shown, the rotor core shaft 15 includes a core shaft connecting sleeve 5, a front core shaft 4, a front tie rod 8, a core shaft front journal 7, a tie rod front journal 3, an oil distribution sleeve 1, a rear core shaft 9 and a core shaft rear journal 6; wherein,

[0100] The front core shaft 4 and the front tie rod 8 are both thin-walled tubes with a wall thickness of 1.5mm and a length of 430mm; the front tie rod 8 is sleeved on the front core shaft 4 and is connected to one end of the core shaft connecting sleeve 5, the end of the front core shaft 4 away from the core shaft connecting sleeve 5 is connected to the core shaft front journal 7, and the end of the front tie rod 8 away from the core shaft connecting sleeve 5 is provided with a tie rod front journal 3, the oil distributor sleeve 1 is matched with the inner diameter of the tie rod front journal 3 and the inner diameter of the core shaft front journal 7, and the matching method is H7 / g6; the outer circle of the tie rod front journal 3 is interference fit with the front shaft assembly 2 in the unit to drive the front bearing to rotate.

[0101] The rear mandrel 9 is a thin-walled tube with a wall thickness of 1.7 mm and a length of 240 mm. One end of the rear mandrel 9 is connected to the end of the mandrel connecting sleeve 5 away from the front mandrel 4, and the other end is connected to the mandrel rear journal 6, and a spline key is provided on the mandrel rear journal 6.

[0102] Based on the above structure, the specific processing steps of the rotor core shaft 15 in the embodiment of the present application are as follows:

[0103] S101, welding and connecting the front journal 7, the front core shaft 4 and the core shaft connecting sleeve 5 of the core shaft to form a reference section. In this embodiment, the welded front journal 7, the front core shaft 4 and the core shaft connecting sleeve 5 of the core shaft are used as the reference section. Due to the short length and the small number of welds, the reference section can be prevented from having a large radial runout after welding. In addition, this arrangement is more conducive to the subsequent welding of other parts of the rotor core shaft 15 (see below for details). Specifically, during the implementation process, first, the front journal 7, the front core shaft 4 and the core shaft connecting sleeve 5 of the core shaft are fixed on the first welding tool; then, the fixed front journal 7, the front core shaft 4 and the core shaft connecting sleeve 5 of the core shaft are placed in a vacuum environment, and the weld position is welded using vacuum electron beam welding. It should be noted that the key matching dimensions between the front shaft neck 7, the front shaft 4 and the shaft connecting sleeve 5, as well as the key matching dimensions between the front shaft neck 7, the front shaft 4 and the shaft connecting sleeve 5 and other components of the rotor shaft 15 are reserved with a 0.2mm margin on one side and processed after welding. In this way, the assembly accuracy of the parts can be better guaranteed.

[0104] Regarding the first welding tool mentioned above, Figure 2 As shown, it includes a support rod 11 and a locking plug 10, wherein the support rod 11 passes through the inner holes of the mandrel front journal 7, the front mandrel 4 and the mandrel connecting sleeve 5, and is threadedly connected with the locking plug 10, the support rod 11 has a cap end, and the diameter of the cap end is larger than the diameter of the mandrel connecting sleeve 5, and similarly, the locking plug 10 is also provided with a cap end, and the diameter of the cap end is larger than the diameter of the inner hole of the mandrel front journal 7. In this way, after the support rod 11 and the locking plug 10 are threadedly connected, an axial limiting groove can be formed on the outer side of the circumference of the first welding tool, and the mandrel front journal 7, the front mandrel 4 and the mandrel connecting sleeve 5 are located in the axial limiting groove, thereby effectively preventing the mandrel front journal 7, the front mandrel 4 and the mandrel connecting sleeve 5 from relative movement in the axial direction. In addition, the gap between the inner hole of the front journal 7 of the core shaft, the inner hole of the front core shaft 4 and the inner hole of the core shaft connecting sleeve 5 and the first welding tool is in the range of 0.05-0.1mm. In this way, it can avoid that the fitting clearance is too large, and the first welding tool cannot constrain the radial movement of the front journal 7 of the core shaft, the front core shaft 4 and the core shaft connecting sleeve 5, causing the parts to be affected by the thermal deformation of welding and the radial runout is too large; when the fitting clearance is too small, the bottom lock gap of the part weld is too small, and the tool cannot be removed normally after slight deformation during welding.

[0105] Furthermore, the first welding tool is provided with an avoidance groove corresponding to the weld position to avoid shrinkage and deformation of the weld during welding, and interference of the weld position resulting in the tool being unable to be removed; illustratively, the width of the avoidance groove can be set to 10 mm, and the depth can be set to 0.3 mm; and, the side wall of the avoidance groove is provided with an arc transition on the side away from the bottom of the groove to facilitate the removal of the tool after welding. Furthermore, a plurality of avoidance grooves are arranged at intervals in the axial direction of the support rod 11, that is, the first welding tool is not only provided with avoidance grooves corresponding to the weld position, but also at other positions, so that it is easier to remove the tool after welding. In addition, a 60° top hole is provided at the center position of the end of the locking plug 10 away from the support rod 11, so that it is easier to align the parts during welding, and thus more accurately ensure the penetration depth.

[0106] Since the welding connection between the front journal 7 of the mandrel, the front mandrel 4 and the mandrel connecting sleeve 5 adopts the welding method of electron beam welding; therefore, the material of the first welding tool must be a non-magnetic material to avoid the electron beam being affected by the first welding tool during the welding process and being offset, thereby failing to accurately weld the weld. In addition, the thermal expansion coefficient of the material of the first welding tool also needs to be similar to the thermal expansion coefficient of the rotor mandrel 15 to avoid the first welding tool being unable to be removed after welding is completed, or the first welding tool being unable to effectively constrain the deformation of the front journal 7 of the mandrel, the front mandrel 4 and the mandrel connecting sleeve 5 during the welding process. In this embodiment, based on the material of the rotor mandrel 15 being 1Cr11Ni2W2MoV, the material of the first welding tool can be 304 stainless steel.

[0107] S301. Eliminate welding stress at high temperature to prevent cracking at the weld. When removing stress, place the welded parts vertically in an air furnace by hanging. Heat the air furnace to 550℃±10℃ under natural conditions and keep it warm for 90 minutes, then cool it quickly to 300℃ and keep it warm for 3 hours, and then cool it slowly to 150℃ to remove stress at the welding position, thereby preventing the parts from being affected by the cutting force and releasing stress, which may cause deformation of the parts.

[0108] S302. Weld inspection: Radiographic inspection of weld position, penetration depth, internal defects of welds and weld accuracy must meet GJB1718-93 Grade I weld standards.

[0109] S303, sequential fluorescence detection: detect welding defects such as cracks and slag inclusions on the outer surface of the weld.

[0110] S304, perform runout detection on the reference section formed in step S101, specifically, use the middle section of the former mandrel 4 as the machining alignment reference, and align the entire section radial runout <0.05mm, thereby ensuring the coaxiality between the machining end and the non-machining end of the part. In this step, if the detection fails, the part will be scrapped.

[0111] S102, remove material from the reference section formed in step S101, specifically, clamp the middle section of the front mandrel 4, and process the outer circle of the mandrel connecting sleeve 5 and its end face away from the front mandrel 4; after the processing, take the outer circle of the mandrel connecting sleeve 5 as the reference, process the inner hole and outer circle of one end of the mandrel front journal 7, and ensure that the coaxiality of the inner hole and outer circle with the outer circle of the mandrel connecting sleeve 5 is 0.025mm (the reference section after processing can refer to Figure 3 ).

[0112] S103, spot welding the rear mandrel 9 and the mandrel connecting sleeve 5, and detecting the radial runout of the rear mandrel 9 based on the reference section;

[0113] S104, if the radial runout of the rear mandrel 9 meets the second preset requirement, proceed to the next step; if the radial runout of the rear mandrel 9 does not meet the second preset requirement, remove the spot welding fixing point between the rear mandrel 9 and the connecting sleeve, adjust the relative position of the rear mandrel 9 and the connecting sleeve, and repeat step S103 until the radial runout of the rear mandrel 9 meets the second preset requirement;

[0114] S201, spot welding and fixing the other structures in the rotor core shaft 15 such as the rear journal 6 of the core shaft, and detecting the radial runout of the above structures with reference to the reference section,

[0115] S202. If the radial runout of the above structure (including the oil distribution sleeve 1, the rear journal 6 of the core shaft, the front pull rod 8 and the front journal 3 of the pull rod and other components of the rotor core shaft 15) meets the third preset requirement, proceed to the next step. If the radial runout of the above structure does not meet the third preset requirement, remove the spot welding fixing points between the second pipe segment and the above structure, adjust the relative position of the second pipe segment and the above structure, and repeat step S201 until the radial runout of the above structure meets the third preset requirement.

[0116] S105, using welding technology to seal and connect the above-mentioned structure fixed by spot welding. Specifically, Figure 4 As shown, the above-mentioned parts fixed by spot welding are assembled on the second welding fixture, and the second welding fixture includes a first axial fixing portion 12, a second axial fixing portion 13, and a plurality of threaded rods 14 connecting the first axial fixing portion 12 and the second axial fixing portion 13. After the assembly is completed, the parts are placed in a vacuum environment, and the weld seams in the rotor core shaft 15 except the reference section are welded using the verified welding parameters.

[0117] S106, re-measure the outer circle runouts with the front pull rod 8 and the rear mandrel 9 as references, and mark the data of the high point of the runout on the parts with a marking pen.

[0118] S107, placing the rotor core shaft 15 in the V-shaped groove, and measuring the height of the top of the rotor core shaft 15 from the table surface of the base 17, and the measured position is the position marked with a marker in step S106.

[0119] S108. At the position where the measurement result shows a higher position, use the arc-shaped surface contact type pressure ring 16 and M8 bolts to lock, and the tightening torque is 10N.m. At the position where the measurement result shows a lower position, set a copper gasket to adjust the height of the rotor core shaft 15 (for details, please refer to Figure 5 ).

[0120] S109, re-measure the height between the top of the rotor core shaft 15 and the table surface of the base 17.

[0121] S110, calculating the height difference of different measuring positions, and ensuring that the height error of different positions of the rotor core shaft 15 is less than 0.05 mm, otherwise repeating steps S108 and S109.

[0122] S111. Place the V-shaped fixture with the rotor core shaft 15 fixed in a stress relief furnace, remove the welding stress of the rotor core shaft 15 at high temperature, and straighten the rotor core shaft 15; specifically, after the rotor core shaft 15 is fixed, heat the V-shaped fixture and the rotor core shaft 15 as a whole with the furnace to 550℃±10℃, keep warm for 7 hours, quickly cool to 300℃, keep warm for 2 hours, and air cool. This high-temperature and long-term method can completely remove the welding stress at the weld position, preventing the parts from releasing stress during processing and causing larger runout. At the same time, the runout of the parts can be corrected by anti-deformation thermal calibration.

[0123] It should be noted that if the radial runout of the rotor core shaft 15 after welding is less than 0.2 mm, steps S107 to S110 may be omitted as needed.

[0124] S701. Weld flaw detection: Weld flaw detection is performed after stress relief to prevent weld defects caused by high temperature stress relief. The weld accuracy of the weld must meet the GJB1718-93 Grade I weld standard.

[0125] S112, block one end face of the rotor core shaft 15 and the vent holes on the circumferential side of the rotor core shaft 15; the steps of blocking the vent holes are as follows: S401, process a sealing groove 18 on the circumferential outer side of the raised structure surrounding the core shaft connecting sleeve 5 and the rear core shaft 9, and set a sealing ring inside the sealing groove 18. It should be noted that in order to avoid waste chips blocking the vent holes on the side wall of the rotor core shaft 15 during processing, the vent holes between adjacent raised structures can be sealed with electrical tape to prevent iron filings and impurities from entering the flow channel. Before turning, the tooling first clamps the core shaft connecting sleeve 5, and the center frame assists in supporting the outer circle of the front journal 3 of the pull rod. During the turning process, the coolant is used to continuously cool the rotor core shaft 15 to prevent it from being affected by the cutting heat and causing the parts to jump out more. The end face of the oil separation sleeve 1 and the process internal thread M18*1.5 are turned to facilitate the subsequent connection of the oil separation sleeve 1 to the hydraulic press. In addition, in this embodiment, the specific method of turning is as follows: first, turn the outer circle (the size of the outer circle after turning is φ59.5mm) and the end face of the front journal 3 of the tie rod to form a clamping reference. Turn around and clamp the above outer circle reference, and use the center frame to assist in supporting the front tie rod 8, and turn the sealing groove 18 at 4. It should be noted that the bottom diameter of the sealing groove 18 here is larger than the subsequent fine turning diameter of this position, to ensure that there is enough fine turning margin at the bottom of the groove after the step is removed (the rotor core shaft 15 after turning the sealing groove 18 can refer to Figure 6 S402: A sealing ring (not shown) is sleeved on the rotor core shaft 15, and the sealing ring is sealed and connected to the protruding structures on both sides of the vent hole on the rotor core shaft 15 through the sealing ring.

[0126] S113, sealingly connecting the other end of the rotor core shaft 15 to the hydraulic press, using the hydraulic press to increase the internal pressure of the rotor core shaft 15 to 15 MPa, and maintaining the preset pressure;

[0127] S114. After maintaining the pressure for 5 minutes, observe whether there is leakage at the weld position. If there is no leakage at the weld position, the welding air tightness of the welding position meets the requirements.

[0128] S501, clamp the front journal 3 of the tie rod, use the center frame to assist in supporting the rear spindle 9, turn the various features of the outer circle and inner hole of the rear journal 6 of the spindle, and allow 0.15-0.2mm on one side of the outer circle. After the inner hole is processed, screw in the second fine-ground plug 22, and drill an A1.6 center hole on the tail top of the second fine-ground plug 22. After that, remove the center frame, fine-turn the sealing groove 18 on the spindle connecting sleeve 5, and fine-turn the various features of the outer circle of the front journal 3 of the tie rod, and the diameter allowance of the outer circle matching position in this process is 0.35mm-0.4mm.

[0129] S115, the gear-slotting tool 19 is sleeved on the sealing groove 18 of the rear spindle 9, and the gear-slotting tool 19 is fixed, that is, in this embodiment, the sealing groove 18 of the rear spindle 9 is also the installation groove of the gear-slotting tool 19. It should be noted that in this step, the matching clearance between the outer diameter of the gear-slotting tool 19 and the sealing groove 18 should be less than 0.02 mm. In addition, the gear-slotting tool 19 is fixed to the rear spindle 9 in the following manner: the tip of the M5 screw 20 is processed to form a protrusion with a diameter of 2 mm and a height of 1 mm, and the screw 20 is passed through the gear-slotting tool 19 and then screwed into the sealing groove 18 to ensure that the bottom of the sealing groove 18 is stressed, so as to prevent the screw 20 and the rotor spindle 15 from being deformed due to uneven stress, thereby making it impossible to remove the gear-slotting tool 19.

[0130] S601. Clamp the outer circle of the rear journal 6 of the mandrel, and use the center frame to assist in supporting the outer circle of the front journal 3 of the tie rod. Fine-turn the total length of the oil-distributing sleeve 1 and the various features of its inner hole. The inner hole of the oil-distributing sleeve 1 is interference-fitted with the first fine-ground plug 21, and the interference is ensured to be less than 0.015mm. Install the first fine-ground plug 21 into the inner hole, drill the A1.6 center hole, push the center hole to disassemble the center frame, push the center hole to the rear, fine-turn the end face of the gear shaping tool 19, and ensure that the verticality of the end face and the outer circle is less than 0.02mm (for details, please refer to Figure 7 ).

[0131] S602, grinding datum: taking the center hole as the datum, fine-grind the outer circle features of the double-top center hole to ensure a diameter allowance of 0.15-0.2mm, fine-grind the end face of the gear shaping tool 19 until it is exposed to light, and ensure that the verticality of the end face to the center hole datum is less than 0.01mm and the flatness is 0.01mm.

[0132] S116, fixing the rotor core shaft 15 on the gear shaping workbench, and making the end surface of the gear shaping tool 19 fit with the corresponding plane of the gear shaping workbench to ensure the processing accuracy of the spline teeth.

[0133] S117, using a gear shaping device to process spline teeth at corresponding positions of the rotor core shaft 15.

[0134] S118, clamp the outer circle of the front journal 3 of the tie rod, top the center hole of the tail, finish turning to remove the two process sealing grooves 18, finish turning the outer circumference of the rotor core shaft 15, and reserve a fine grinding allowance of 0.15mm-0.2mm;

[0135] S119. Grind the outer diameters of the double-top center holes to the required dimensions of the design drawings. After grinding, remove the tooling at both ends.

[0136] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.

[0137] The block diagrams of the devices, apparatuses, equipment, and systems involved in this application are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagram. As will be appreciated by those skilled in the art, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open words, referring to "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used here refer to the words "and / or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The words "such as" used here refer to the phrase "such as but not limited to", and can be used interchangeably with them.

[0138] It should also be noted that in the apparatus, device and method of the present application, each component or each step can be decomposed and / or recombined. Such decomposition and / or recombination should be regarded as equivalent solutions of the present application.

[0139] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

[0140] It should be understood that the qualifiers "first", "second", "third", "fourth", "fifth" and "sixth" used in the description of the embodiments of the present application are only used to more clearly explain the technical solutions and cannot be used to limit the scope of protection of the present application.

[0141] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A mandrel processing process, characterized in that: The mandrel comprises a first pipe section and a second pipe section, and the first pipe section and the second pipe section are connected via a connecting sleeve. The mandrel processing process comprises the following steps: S101, using a welding process to seal and connect an end surface of the first pipe segment and an end surface of the connecting sleeve to form a reference segment; S102, performing material removal processing on the reference segment so that the radial runout of the outer circle of the reference segment and the perpendicularity between the other end surface of the connecting sleeve and the axial direction of the reference segment meet a first preset requirement; S103, fixing the second pipe segment and the connecting sleeve by spot welding, and detecting the radial runout of the second pipe segment with the reference segment as a reference; S104, if the radial runout of the second pipe segment meets the second preset requirement, proceed to the next step; if the radial runout of the second pipe segment does not meet the second preset requirement, remove the spot welding fixing point between the second pipe segment and the connecting sleeve, adjust the relative position of the second pipe segment and the connecting sleeve, and repeat step S103 until the radial runout of the second pipe segment meets the second preset requirement; S105, using a welding process to seal and connect different components of the core shaft fixed by spot welding.

2. The core shaft processing process according to claim 1, characterized in that: The mandrel further includes a journal section, and the journal section is welded to an end surface of the second pipe section at one end away from the connecting sleeve. The following steps are further included between step S104 and step S105: S201, fix the second pipe segment and the shaft neck segment by spot welding, and detect the radial runout of the shaft neck segment with the reference segment as the reference, S202. If the radial runout of the shaft neck segment meets the third preset requirement, proceed to the next step. If the radial runout of the shaft neck segment does not meet the third preset requirement, remove the spot welding fixing points between the second pipe segment and the shaft neck segment, adjust the relative position of the second pipe segment and the shaft neck segment, and repeat step S201 until the radial runout of the shaft neck segment meets the third preset requirement.

3. The core shaft processing process according to claim 1, characterized in that: After step S105, the mandrel is straightened by using a V-shaped tool, wherein the V-shaped tool comprises a base provided with a V-shaped groove and a pressure ring that can be connected to the base. Straightening the mandrel by using the V-shaped tool comprises the following steps: S106, using the first pipe segment and the second pipe segment as references respectively, detecting radial runout at each position of the mandrel, and marking positions on the mandrel where radial runout exceeds a first threshold range; S107, placing the mandrel in the V-shaped groove, and measuring the height of the top of the mandrel from the table of the base, and the measuring position is the position where the radial runout marked on the mandrel exceeds the first threshold range; S108, setting the pressure ring at a position where the measurement result is greater than a second threshold range, and setting a gasket at a position where the measurement result is less than the second threshold range; S109, re-measure the height of the top of the mandrel from the table of the base, and the measurement position is consistent with step S107; S110, calculating the height difference of different measuring positions, if the height difference meets the fourth preset requirement, proceeding to the next step, if the height difference does not meet the fourth preset requirement, repeating steps S108 and S109 until the height difference meets the fourth preset requirement; S111, placing the V-shaped tooling with the mandrel fixed thereon in a stress relief furnace, removing the welding stress of the mandrel at high temperature, and straightening the mandrel.

4. The core shaft processing process according to claim 1, characterized in that: The method also includes an airtightness detection process, wherein the airtightness detection process includes the following steps: S112, sealing one end surface of the mandrel and the through hole on the circumferential side surface of the mandrel; S113, sealingly connecting the other end of the mandrel to a hydraulic press, using the hydraulic press to increase the internal pressure of the mandrel to a preset pressure, and maintaining the preset pressure; S114, observing whether there is leakage at the weld position, and if there is no leakage at the weld position within a preset time period, the welding air tightness of the weld position meets the requirements.

5. The core shaft processing process according to claim 1, characterized in that: The outer circumferential surface of the mandrel is provided with spline teeth, and the mandrel is provided with a first protrusion for fixing a gear-slotting tool. The processing steps of the spline teeth are as follows: S115, sleeve a gear shaping tool on the position of the mandrel where the first protrusion is provided, and fix the gear shaping tool; S116, fixing the mandrel on the gear shaping workbench, and making the end surface of the gear shaping tool fit with the corresponding plane of the gear shaping workbench; S117, using a gear shaping device to process spline teeth at corresponding positions of the mandrel.

6. The core shaft processing process according to claim 1, characterized in that: In step S101, the first pipe section and the connecting sleeve are both assembled on a first welding tool; The first welding tool includes a support rod and a locking plug. The support rod axially penetrates the first pipe section and the connecting sleeve and is threadedly connected to the locking plug to form an axial limit groove on the circumferential outer side of the first welding tool. The axial limit groove can limit the movement of the first pipe section and the connecting sleeve in the axial direction, and the gap between the support rod and the first pipe section ranges from 0.05mm to 0.1mm.

7. The core shaft processing process according to claim 1, characterized in that: The following steps are also included between step S101 and step S102: S301, placing the reference segment after welding in a stress relief furnace to remove welding stress.

8. The core shaft processing process according to claim 4, characterized in that: The circumferential side surface of the mandrel has a through hole, and along the axial direction of the mandrel, second protrusions are arranged on both sides of the through hole. The steps of blocking the through hole on the circumferential side surface of the mandrel are: S401, processing a sealing groove around the outer circumference of the second protrusion, and disposing a sealing ring inside the sealing groove; S402, sleeve a sealing ring on the core shaft, and make the sealing ring and the second protrusions on both sides of the through hole sealed and connected through the sealing ring.

9. The core shaft processing process according to claim 5, characterized in that: The following steps are also included: S118, finishing turning the outer circumference of the mandrel, and reserving a finishing allowance of 0.15 mm to 0.2 mm; S119, fine grinding the dimensions from the circumferential outer side of the mandrel to each position of the mandrel to meet the fifth preset requirement.

10. The core shaft processing process according to claim 5, characterized in that: In step S115, the fitting clearance between the gear inserting tool and the first protrusion is less than 0.02 mm.

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