Machining method for shaft inner hole

Abstract

The invention provides a shaft inner hole machining method, and belongs to the technical field of machining. The machining method comprises the steps that rough machining is conducted on a blank piece of the load limiting shaft, so that an in-shaft coarse hole is formed in the blank piece of the load limiting shaft; carrying out thermal refining on the blank piece of the load limiting shaft; the outer circle and the end face of the blank piece of the load limiting shaft are subjected to finish machining; and honing the in-shaft coarse hole to obtain the in-shaft hole. The machining difficulty of the shaft inner hole can be reduced.

Description

Technical Field

[0001] The present invention belongs to the field of mechanical processing technology, and in particular relates to a method for processing an inner hole of a shaft. Background Art

[0002] The load limit shaft is an important part of the chain drive assembly, usually made of 40CrNiMo alloy steel with a high strength grade. As an important part of the chain drive, the load limit shaft is required to be heat treated during use to improve its comprehensive mechanical properties and make its overall hardness index reach HRC50 or above. The load limit shaft has an inner hole inside so that the telescopic rod can be inserted into the load limit shaft. Therefore, the dimensional tolerance and straightness of the inner hole of the shaft have higher index requirements and need to be strictly controlled during the processing process.

[0003] In the related art, the manufacturing process of the load limit shaft generally includes: firstly heat treating the load limit shaft (i.e., quenching and tempering treatment) to improve its mechanical properties and overall hardness. Then, the load limit shaft is finely processed, and during the fine processing, an alloy steel drill is used to drill the inner hole of the load limit shaft.

[0004] However, since the mechanical properties and overall hardness of the load limit shaft are greatly improved after heat treatment compared to before heat treatment, it is difficult to drill the load limit shaft with an alloy steel drill bit, especially when the drilling depth exceeds 120mm. The drill bit wears greatly and it is difficult to continue the drilling operation, making the processing of the inner hole of the shaft difficult and the processing efficiency low. Summary of the invention

[0005] The embodiment of the present disclosure provides a method for machining an inner hole of a shaft, which can reduce the difficulty of machining the inner hole of the shaft. The technical solution is as follows:

[0006] An embodiment of the present disclosure provides a method for processing an inner hole of a shaft, the processing method comprising: rough machining a blank of a load limiting shaft so that the interior of the blank of the load limiting shaft has a rough hole in the shaft; tempering the blank of the load limiting shaft; fine machining the outer circle and end face of the blank of the load limiting shaft; and honing the rough hole in the shaft to obtain the inner hole in the shaft.

[0007] In another implementation of the present disclosure, the load limiting shaft blank is rough-machined so that the interior of the load limiting shaft blank has a rough hole in the shaft, including: rough turning the end faces and the outer circle of the load limiting shaft blank at both ends; drawing a machining positioning line of the inner hole in the shaft on the load limiting shaft blank after rough turning; and drilling the rough hole in the shaft on the load limiting shaft blank by a drill bit according to the machining positioning line.

[0008] In yet another implementation of the present disclosure, the diameter of the coarse hole in the shaft is 0.8 to 1 mm smaller than the diameter of the inner hole in the shaft.

[0009] In another implementation of the present disclosure, the tempering treatment of the blank of the load limiting shaft includes: placing the blank of the load limiting shaft upright on a pallet so that the extension direction of the rough hole in the shaft is a vertical direction; placing the pallet and the blank of the load limiting shaft in a heating furnace for heating, and quenching after heating; placing the pallet and the blank of the load limiting shaft in the heating furnace for tempering.

[0010] In another implementation of the present disclosure, honing the rough hole in the shaft to obtain the inner hole of the shaft includes: using a series of honing heads to gradually expand the inner hole of the shaft so that the hole diameter and roughness of the inner hole of the shaft meet the requirements, and the series of honing heads includes multiple honing heads with different diameters, and the diameters of the multiple honing heads gradually increase.

[0011] In yet another implementation of the present disclosure, the diameters of the plurality of honing heads are 0.5-3 mm, and the diameters of the plurality of honing heads gradually increase.

[0012] In another implementation of the present disclosure, the finish machining of the outer circle and the end face of the blank of the load limiting shaft includes: placing the blank of the load limiting shaft in a lathe, and making the center line of the rough hole in the shaft coincide with the rotation center of the lathe; correcting the blank of the load limiting shaft so that the end face of the blank of the load limiting shaft is parallel to the workbench; finish turning one of the end faces of the blank of the load limiting shaft, and using the end face after finish turning as a reference for the remaining finish machining; finish turning the outer circle and the other end face of the blank of the load limiting shaft so that all dimensions of the load limiting shaft meet the requirements of the drawing.

[0013] In another implementation of the present disclosure, before finishing the outer circle and end surface of the blank of the load limiting shaft, the processing method further includes:

[0014] An ultrasonic flaw detection is performed on the blank of the load limiting shaft to detect whether there are defects in the blank of the load limiting shaft.

[0015] In yet another implementation of the present disclosure, the processing method further includes: deburring and cleaning the load limit shaft after honing.

[0016] In yet another implementation of the present disclosure, the processing method further comprises: before performing a quenching and tempering treatment on the blank of the load limiting shaft, performing an annealing treatment on the blank of the load limiting shaft after rough machining.

[0017] The technical solution provided by the embodiments of the present disclosure has the following beneficial effects:

[0018] When the above processing method is used to process the inner hole of the load-limiting shaft, since the processing method firstly rough-machines the inner hole of the shaft in the blank of the load-limiting shaft, and then performs a tempering treatment (i.e., heat treatment) on the load-limiting shaft, the inner hole of the shaft can be located before the tempering treatment, reducing the difficulty of processing the inner hole of the shaft, thereby improving the processing efficiency of the entire process of the inner hole of the shaft. Next, the blank of the load-limiting shaft is tempered, so that the structural strength of the load-limiting shaft finally processed meets the use requirements. Next, the processing method is to fine-machine the outer circle and end face of the blank of the load-limiting shaft, and hone the inner hole of the shaft, so that the load-limiting shaft can meet the size requirements of the drawing through fine machining, and the inner hole of the shaft can be further processed through honing, so that after the inner hole of the shaft is honed, the various dimensional requirements such as roughness can also meet the size requirements of the drawing, thereby obtaining the inner hole of the shaft.

[0019] That is to say, through the above processing method, the processing problem of the inner hole of the load limit shaft can be effectively solved. At the same time, the inner hole of the shaft obtained after honing can also effectively improve its processing accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 It is a structural schematic diagram of a load limiting shaft in the related art;

[0022] Figure 2 is a flow chart of a method for machining an inner hole of a shaft provided by an embodiment of the present disclosure;

[0023] Figure 3 is a flow chart of another method for machining an inner hole of a shaft provided by an embodiment of the present disclosure;

[0024] Figure 4 It is a structural schematic diagram of the blank of the load limiting shaft;

[0025] Figure 5 It is a schematic diagram of the structure of a blank of a load-limiting shaft with a rough hole in the shaft.

[0026] The symbols in the figure mean the following:

[0027] 100. Load limit axis;

[0028] 101, first shaft section; 102, second shaft section; 103, third shaft section; 104, fourth shaft section; 105, fifth shaft section; 106, sixth shaft section;

[0029] 1010, shaft inner hole;

[0030] 1020. Countersink. DETAILED DESCRIPTION

[0031] In order to make the objectives, technical solutions and advantages of the present disclosure more clear, the embodiments of the present disclosure will be further described in detail below with reference to the accompanying drawings.

[0032] Unless otherwise defined, the technical terms or scientific terms used herein shall have the usual meanings understood by persons with ordinary skills in the field to which the present disclosure belongs. The words "first", "second", "third" and similar words used in the patent application specification and claims of the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "one" do not indicate a quantity limitation, but indicate the existence of at least one. Words such as "include" or "comprise" and similar words mean that the elements or objects appearing before "include" or "comprise" include the elements or objects listed after "include" or "comprise" and their equivalents, and do not exclude other elements or objects. Words such as "connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right", "top", "bottom" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0033] The load limit shaft is an important part of the chain drive assembly, usually made of 40CrNiMo alloy steel with a high strength grade. As an important part of the chain drive, the load limit shaft is required to be heat treated during use to improve its comprehensive mechanical properties. That is, the overall hardness index of the load limit shaft is required to reach HRC50 or above.

[0034] Figure 1 It is a schematic diagram of the structure of the load limit shaft in the related technology, combined with Figure 1 The load limiting shaft 100 is provided with an elongated shaft inner hole 1010. The length direction of the shaft inner hole 1010 is the same as the length direction of the load limiting shaft 100. The inner diameter of the shaft inner hole 1010 is 8 mm.

[0035] The shaft inner hole 1010 is used to provide a movable space for the telescopic rod. Part of the telescopic rod is movably located in the shaft inner hole 101, and the telescopic rod can be telescoped relative to the load limiting shaft 100.

[0036] In order to ensure that the telescopic movement of the telescopic rod does not deviate, the dimensional tolerance and straightness of the shaft inner hole 1010 have higher index requirements and need to be strictly controlled during the processing.

[0037] In addition, the end surfaces of both ends of the load limiting shaft 100 are respectively provided with countersunk holes 1020. The inner diameter of the countersunk holes 1020 is 30 mm, and the hole depth of each countersunk hole 1020 along the length direction of the load limiting shaft 100 is 10 mm. The two countersunk holes 1020 are respectively connected to the two ends of the shaft inner hole 1010.

[0038] The outer dimensions of the load limiting shaft 100 are Φ92×300 mm. The load limiting shaft 100 comprises a first shaft section 101, a second shaft section 102, a third shaft section 103, a fourth shaft section 104, a fifth shaft section 105 and a sixth shaft section 106 which are sequentially connected along the length direction thereof.

[0039] The length of the first shaft segment 101 is 14.5 mm, and the outer diameter of the first shaft segment 101 is 68 mm.

[0040] The length of the second shaft segment 102 is 55.5 mm, and the outer diameter of the second shaft segment 102 is 80 mm.

[0041] The length of the third shaft segment 103 is 60 mm, and the outer diameter of the second shaft segment 102 is 92 mm.

[0042] The length of the fourth shaft segment 104 is 100 mm, and the outer diameter of the second shaft segment 102 is 87 mm.

[0043] The length of the fifth shaft segment 105 is 55.5 mm, and the outer diameter of the second shaft segment 102 is 80 mm. The fifth shaft segment 105 has the same structure as the second shaft segment 102.

[0044] The length of the sixth shaft segment 106 is 14.5 mm, and the outer diameter of the sixth shaft segment 106 is 68 mm. The sixth shaft segment 106 has the same structure as the first shaft segment 101 .

[0045] One of the two counterbores 1020 is located in the first shaft segment 101 , and the other of the two counterbores 1020 is located in the sixth shaft segment 106 .

[0046] In the related art, in order to ensure the processing quality of the shaft inner hole 1010, the shaft inner hole 1010 is usually arranged to be completed in the last finishing process of the load-limiting shaft.

[0047] Since the load limit shaft has been heat treated in the previous processing steps, the mechanical properties and overall hardness of the load limit shaft have been greatly improved compared to before the heat treatment. After that, during the fine processing, the load limit shaft is drilled to process the inner hole of the shaft, which is difficult to achieve with ordinary alloy steel drill bits, especially when the drilling depth exceeds 120mm, the drill bit is greatly worn and it is difficult to continue to complete the drilling operation. Even if a solid carbide drill bit is used, the feed rate can only be set very small, and in order to avoid the carbide drill bit from cracking due to poor chip removal during the processing process, the cutting amount during each drilling tool feed is only 0.1~0.2mm, which is basically processed by the grinding loss of the drill tool. Therefore, during the drilling process, the feed and retract strokes are long, and the actual effective processing time and processing volume are very small, resulting in very low processing efficiency. In addition, the wear of the solid carbide drill bit is large, and the tool cost is high, resulting in a very high overall processing cost.

[0048] However, if the inner hole of the slender shaft is processed first and then tempered to improve the overall hardness of the load limit shaft, the part will be deformed due to the heat treatment, which will affect the forming accuracy of the inner hole of the shaft.

[0049] Through the above analysis of the processing technology of the load limit shaft, it is found that the conventional single processing technology can no longer effectively meet its processing quality requirements, or in order to meet its processing accuracy requirements, the time and cost will be very huge. Therefore, in order to solve the processing problem of the load limit shaft, a comprehensive analysis is required and a new processing technology solution is adopted to effectively solve the above problems.

[0050] The present disclosure provides a method for machining a shaft inner hole. Figure 2 As shown, this processing method is used to process the inner hole of the limited load shaft mentioned above. The processing method includes:

[0051] S201: Rough machining is performed on a blank of the load limiting shaft so that the blank of the load limiting shaft has an inner rough hole.

[0052] S202: Performing quenching and tempering treatment on the blank of the load limit shaft.

[0053] S203: Finishing the outer circle and end surface of the blank of the load limiting shaft.

[0054] S204: honing the rough hole in the shaft to obtain the inner hole of the shaft.

[0055] When the above processing method is used to process the inner hole of the load-limiting shaft, since the processing method firstly rough-machines the inner hole of the shaft in the blank of the load-limiting shaft, and then performs a tempering treatment (i.e., heat treatment) on the load-limiting shaft, the inner hole of the shaft can be located before the tempering treatment, reducing the difficulty of processing the inner hole of the shaft, thereby improving the processing efficiency of the entire process of the inner hole of the shaft. Next, the blank of the load-limiting shaft is tempered, so that the structural strength of the load-limiting shaft finally processed meets the use requirements. Next, the processing method is to fine-machine the outer circle and end face of the blank of the load-limiting shaft, and hone the inner hole of the shaft, so that the load-limiting shaft can meet the size requirements of the drawing through fine machining, and the inner hole of the shaft can be further processed through honing, so that after the inner hole of the shaft is honed, the various dimensional requirements such as roughness can also meet the size requirements of the drawing, thereby obtaining the inner hole of the shaft.

[0056] That is to say, through the above processing method, the processing problem of the inner hole of the load limit shaft can be effectively solved. At the same time, the inner hole of the shaft obtained after honing can also effectively improve its processing accuracy.

[0057] On the other hand, the embodiment of the present disclosure also provides another method for machining the inner hole of a shaft, such as Figure 3 As shown, the processing method includes:

[0058] S301: Provide a blank of a load limiting shaft.

[0059] In this embodiment, the blank of the load limiting shaft is rough-machined so that the inside of the blank of the load limiting shaft has a rough inner hole.

[0060] When rough machining the blank of the load limit shaft, not only the outer surface and end face of the blank of the load limit shaft need to be rough machined, but also a rough hole in the shaft needs to be drilled inside the blank of the load limit shaft.

[0061] Optionally, step S301 may be implemented in the following manner:

[0062] 3011: Cut the blank of the load limit shaft.

[0063] 3012: Rough turning of both end faces and outer circle of the load limit shaft.

[0064] During rough machining, the outer circle of the blank of the load limit shaft may be rough turned first, so that a diameter margin of about 8 to 15 mm is reserved for the blank of the load limit shaft after rough turning.

[0065] Figure 4 This is a schematic diagram of the structure of the blank of the load limit shaft, see Figure 4The blank of the load limit shaft is a columnar structure. After rough turning, the outer diameter of the blank of the load limit shaft is 100mm.

[0066] By rough turning the outer circle of the blank of the load limiting shaft, the black skin formed by oxidation on the outer surface of the blank of the load limiting shaft can be removed.

[0067] Then, the end faces of both ends of the blank of the load limit shaft are rough turned.

[0068] When rough turning the end surfaces of both ends of the load limiting shaft blank, it is necessary to leave a machining allowance of 10 mm for the length of the load limiting shaft blank after rough turning.

[0069] In this way, a 10mm margin is left in the length to facilitate clamping.

[0070] In addition, during rough turning, the outer corners of both ends are rounded with R1 fillet (the radius of the R1 fillet is 1mm) to prevent cracks during subsequent quenching.

[0071] 3013: Draw the machining positioning line of the inner hole of the load limit shaft on the blank after rough turning.

[0072] Mark the machining positioning line 1011 of the inner hole of the shaft on the blank of the load limit shaft.

[0073] In this embodiment, the machining positioning lines can be drawn on the two end faces of the blank of the load limiting shaft, so as to facilitate the positioning of the subsequent drill bit during drilling.

[0074] After marking, use a sample punch to punch marks at the center of the two end faces of the blank of the load limit shaft. This makes it easier to mark and will not be inconvenient to check due to unclear processing positioning lines.

[0075] 3014: According to the processing positioning line, use a drill to drill out the rough hole in the shaft on the blank of the load limit shaft.

[0076] In this embodiment, drilling the inner hole of the shaft is also completed in the machine tool.

[0077] First, the blank of the load limit shaft is calibrated and clamped on the machine tool.

[0078] Then, an alloy steel drill bit is used to drill the inner hole of the load limit shaft with reference to the machining positioning line drawn on the end surface of the blank of the load limit shaft.

[0079] Figure 5 The schematic diagram of the structure of the blank of the load-limiting shaft with a rough hole in the shaft is shown in FIG. Figure 5 The rough hole drilled in the shaft is 0.8 to 1 mm smaller than the diameter of the final formed shaft hole.

[0080] It should be noted that the processing parameters of the tool when drilling need to be set according to the equipment and tool conditions, and iron chips should be cleaned up in time during the processing to prevent poor chip removal from squeezing the drill bit and causing the drill bit to break.

[0081] In this embodiment, when machining the inner hole, it can be drilled using a common alloy steel drill bit.

[0082] Since the blank of the load limit shaft has not been tempered at the beginning of rough machining, its hardness and strength have not been greatly improved, so the inner hole can be easily obtained by directly drilling with a drill bit.

[0083] The above inner hole drilling method can refer to the inner hole drilling method of a drill bit, which will not be described in detail here.

[0084] S302: Annealing the rough-machined blank of the load-limiting shaft.

[0085] This can eliminate residual stress during roughing and avoid deformation during subsequent finishing.

[0086] During annealing, the rough-machined load-limiting shaft blank can be placed in a heat preservation furnace at 200-500° for 6-8 hours and then cooled to room temperature.

[0087] S303: Performing quenching and tempering treatment on the blank of the load limit shaft.

[0088] The quenching and tempering treatment refers to a double heat treatment method of quenching and high temperature tempering, so that the load limit shaft has good comprehensive mechanical properties.

[0089] High temperature tempering is usually carried out between 300-650℃. The structure obtained after quenching and tempering is tempered troostite, which has high strength, good plasticity and toughness.

[0090] That is to say, the quenching and tempering treatment includes two steps: quenching and high temperature tempering. Quenching is to heat the load limit shaft to a certain temperature and then cool it quickly to make it have high hardness and high strength. Then high temperature tempering is carried out to eliminate the internal stress and brittleness caused by quenching and improve the plasticity and toughness of the workpiece. Quenching and tempering can significantly improve the performance of steel and make it more reliable during use.

[0091] In this embodiment, when performing the quenching and tempering treatment, the following steps can be followed:

[0092] First, the blank of the load-limiting shaft is placed upright on a pallet, with the length direction of the blank of the load-limiting shaft being the vertical direction. The extension direction of the rough hole in the shaft is the vertical direction. The inner hole of the shaft is in a vertical state.

[0093] Next, the blanks of the tray and the load limiting shaft are placed in a heating furnace for heating and then quenching.

[0094] When the blank of the load limit shaft is heated, the blank of the load limit shaft is placed in a pit furnace for heating, which can reduce the heat treatment deformation. The heating temperature of the heating furnace is 300-650°.

[0095] The blanks of the pallet and the load limit shaft are then placed in a heating furnace for tempering.

[0096] During tempering, the heating temperature of the heating furnace is 300-650°.

[0097] After quenching and tempering treatment, the mechanical properties of the load limit shaft blank meet the requirements of σb≥1350MPa, σa≥1250MPa, δ5≥9% (longitudinal), ψ≥45% (longitudinal), Aku2≥27J (longitudinal, room temperature), and hardness HRC50 is accepted.

[0098] S304: Perform ultrasonic flaw detection on the blank of the load limit shaft.

[0099] Since the blank of the load limit shaft has defects inside after heat treatment, in order to avoid defects inside the blank of the load limit shaft, it is necessary to detect the blank of the load limit shaft by ultrasonic flaw detection.

[0100] Ultrasonic flaw detection is carried out in accordance with GB / T6402-2008, level 3 acceptance. If the blank of the load-limiting shaft is found to not meet the acceptance requirements after ultrasonic testing, the aforementioned steps S301-S303 need to be repeated until the blank of the load-limiting shaft meets the GB / T6402-2008, level 3 acceptance standard.

[0101] S305: Finishing the outer circle and end surface of the blank of the load limit shaft.

[0102] When the load limiting shaft blank is finely processed, the load limiting shaft blank can be placed in a lathe, and the center line of the rough hole in the shaft of the load limiting shaft blank is made to coincide with the rotation center of the lathe.

[0103] Next, the blank of the load limiting shaft is corrected so that the end surface of the blank of the load limiting shaft is parallel to the workbench.

[0104] Then, one of the end faces of the blank of the load limit shaft is finish-turned, and the end face after finish-turning is used as a reference for the remaining finish machining.

[0105] Next, the outer circle and the other end face of the load limit shaft blank are precision-turned so that the length and outer diameter of each shaft segment in the load limit shaft blank meet the requirements of the drawing.

[0106] In summary, when finishing the blank of the load limit shaft, according to the drawing requirements of the load limit shaft, the outer circle, end faces and countersunk holes of the blank of the load limit shaft are finished, and each dimension is controlled to meet the requirements.

[0107] It should be noted that during the finishing process, the dimensional tolerances, surface roughness and form and position tolerances of the load limit shaft should also meet the requirements.

[0108] S306: Honing the inner hole of the shaft.

[0109] Honing, also known as boring, is the finishing process of the finished surface using an oilstone (also called a honing stick) embedded in a honing head.

[0110] During honing, the blank of the load-limited shaft is installed on the honing machine table or in the fixture, and the honing head with several oilstones is inserted into the inner hole of the shaft processed during rough machining. The honing head is driven by the machine tool spindle to rotate and make axial reciprocating motion. The honing bar contacts the hole wall of the shaft inner hole with a certain pressure, which can cut off a very thin layer of metal, so that the inner hole of the shaft can be further ground.

[0111] In this embodiment, a hard honing head is used to perform honing on the inner hole of the shaft.

[0112] The inner hole of the shaft is honed by honing heads of a series of diameters. By gradually expanding the hole, the diameter of the inner hole of the load limit shaft gradually reaches the required Φ8 (0 ~ + 0.1) mm, and at the same time, the shape and position tolerance of the hole and the roughness of the hole wall should also meet the requirements.

[0113] The above series of honing heads include multiple honing heads with different diameters, the diameters of the multiple honing heads gradually increase, and the diameters of the multiple honing heads are between 0.5-3 mm.

[0114] By gradually increasing the diameter of the honing head, the honing head can be made to fit together with the inner wall of the rough hole in the shaft in real time, so as to continuously grind the rough hole in the shaft, so that the rough hole in the shaft can meet the size requirements of the shaft hole after grinding, and finally complete the processing of the shaft hole in the load limit shaft.

[0115] S307: Deburring and cleaning the rough workpiece of the load limit shaft after honing.

[0116] In order to make the surface of the load limit shaft smoother and cleaner, the rough workpiece of the load limit shaft is deburred and cleaned after honing.

[0117] Then, after cleaning, the load limit shaft is dried and then stored with oil seal.

[0118] In the disclosed embodiment, when processing the inner hole of the shaft, the processing process of the load limit shaft is changed and the inner hole of the shaft is processed by a combination of "drilling + honing", which effectively solves the problem of processing the inner hole of the shaft in a high-strength load limit shaft. Moreover, it can also improve the overall processing efficiency of the load limit shaft and reduce the process cost while ensuring the processing quality of the load limit shaft.

[0119] The above description is only an optional embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A method for machining an inner hole of a shaft, characterized in that: The processing method comprises: Rough machining is performed on a blank of the load limiting shaft so that the blank of the load limiting shaft has a rough inner hole; Performing quenching and tempering treatment on the blank of the load limiting shaft; Finishing the outer circle and end surface of the blank of the load limiting shaft; The rough hole in the shaft is honed to obtain the shaft inner hole.

2. The processing method according to claim 1, characterized in that: The rough machining of the blank of the load limiting shaft so that the inside of the blank of the load limiting shaft has a rough shaft hole comprises: Rough turning the end faces and outer circle of the blank of the load limiting shaft; Marking a machining positioning line of the inner hole of the shaft on the roughcast of the load-limiting shaft after rough turning; According to the processing positioning line, the rough hole in the shaft is drilled out on the blank of the load limiting shaft by using a drill bit.

3. The processing method according to claim 2, characterized in that: The diameter of the coarse hole in the shaft is 0.8 to 1 mm smaller than the diameter of the inner hole in the shaft.

4. The processing method according to claim 1, characterized in that: The method of subjecting the blank of the load limiting shaft to quenching and tempering includes: Place the blank of the load-limiting shaft upright on a pallet so that the extending direction of the rough hole in the shaft is in the vertical direction; Placing the blanks of the tray and the load limiting shaft in a heating furnace for heating, and quenching after heating; The blanks of the tray and the load limiting shaft are placed in the heating furnace for tempering.

5. The processing method according to claim 1, characterized in that: The method of honing the rough hole in the shaft to obtain the inner hole of the shaft comprises: The inner hole of the shaft is expanded step by step by using a series of honing heads, so that the hole diameter and roughness of the inner hole of the shaft meet the requirements. The series of honing heads includes a plurality of honing heads with different diameters.

6. The processing method according to claim 4, characterized in that: The diameters of the multiple honing heads are all 0.5-3 mm, and the diameters of the multiple honing heads gradually increase.

7. The processing method according to claim 1, characterized in that: The finishing of the outer circle and the end surface of the blank of the load limiting shaft comprises: Placing the blank of the load-limiting shaft in a lathe, and making the center line of the rough hole in the shaft coincide with the rotation center of the lathe; Correcting the blank of the load limiting shaft so that the end surface of the blank of the load limiting shaft is parallel to the workbench; Finish-turn one of the end faces of the blank of the load limit shaft, and use the finish-turned end face as a reference for the remaining finish machining; The outer circle and the other end face of the blank of the load limiting shaft are precision-turned so that all dimensions of the load limiting shaft meet the requirements of the drawing.

8. The processing method according to claim 1, characterized in that: Before finishing the outer circle and end surface of the blank of the load limiting shaft, the processing method further includes: An ultrasonic flaw detection is performed on the blank of the load limiting shaft to detect whether there are defects in the blank of the load limiting shaft.

9. The processing method according to claim 1, characterized in that: The processing method further comprises: deburring and cleaning the load limit shaft after honing.

10. The processing method according to claim 1, characterized in that: The processing method further comprises: before performing a quenching and tempering treatment on the blank of the load limiting shaft, performing an annealing treatment on the blank of the load limiting shaft after rough processing.

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