Machining process for high-strength multi-section hollow spline shaft with inner oil way

Abstract

The invention relates to a machining technology for a high-strength multi-section hollow spline shaft with an inner oil way. The machining technology comprises the following steps that a rod piece with the preset length and diameter is obtained; flattening an end face, turning a clamping position and punching center holes in two ends; rough turning; drilling a through hole; normalizing and destressing; flattening the end surface, returning to the total length, and trimming tip positioning chamfers of orifices at two ends; finely turning the excircle end surface; roughly grinding an outer circle; rolling each section of rectangular spline; drilling a radial oil hole; carburizing, quenching and straightening are conducted; trimming positioning chamfers at two ends; accurately grinding the excircle of each section; drilling and reaming deep holes in two ends and tapping threads; grinding each section of spline; and finally detecting the finished product, cleaning, oiling and warehousing. The integrated heat treatment carburizing and quenching method has the advantages that the strength of the shaft is improved by adopting an integrated heat treatment carburizing and quenching mode, and the core part has sufficient toughness on the premise of ensuring that the surface has sufficient hardened layer depth; the workpiece is subjected to heat treatment normalizing after rough machining, stress is eliminated, heat treatment deformation is greatly reduced, and the size of the part is more stable.

Description

Technical Field

[0001] The invention relates to the field of mechanical processing technology, in particular to a processing technology of a high-strength multi-section hollow spline shaft with an internal oil path. Background Art

[0002] The multi-section hollow spline shaft with internal oil circuit is a part that takes into account mechanical transmission, lubrication and cooling, and hydraulic control. The spline shaft is used to transmit torque. The hollow design with internal oil circuit can reduce the weight of the part and improve product efficiency. Lubrication and cooling are achieved through the internal oil circuit, reducing part wear and preventing material performance degradation caused by overheating. At the same time, the hydraulic wet clutch on the shaft system can be controlled through the internal oil circuit, making the structure more compact.

[0003] In order to achieve the above functions, higher requirements are placed on the precision of parts. Traditional processing technology often finds it difficult to control heat treatment deformation and can only be made into component structures, which increases production costs and complicates structural design.

[0004] Based on this, this case is brought forward. Summary of the invention

[0005] The purpose of the present invention is to provide a processing technology for a high-strength multi-section hollow spline shaft with an internal oil passage to solve the above-mentioned defects.

[0006] In order to achieve the above object, the technical solution of the present invention is as follows:

[0007] A processing technology for a high-strength multi-section hollow spline shaft with an internal oil passage comprises the following steps:

[0008] S01. Cutting, obtaining rods of predetermined length and diameter;

[0009] S02. Flatten the end surface, turn the clamping position, and drill the center holes at both ends;

[0010] S03. Rough turning;

[0011] S04. Drill through holes;

[0012] S05. Normalizing to relieve stress;

[0013] S06. Flat end surface, return to total length, turn the top positioning chamfer of the hole at both ends;

[0014] S07. Finish turning the outer end surface, cutting grooves and chamfering;

[0015] S08. Rough grinding of outer circle;

[0016] S09. Knurled key;

[0017] S10. Drill radial oil holes;

[0018] S11. Heat treatment;

[0019] S12. Repair the chamfering of the top of the holes at both ends;

[0020] S13. Fine grinding of outer circle;

[0021] S14. Drill, expand and ream the holes at both ends, and tap the threads;

[0022] S15. Grinding splines;

[0023] S16. After the inspection meets the standards, the products will be put into storage.

[0024] Furthermore, the step S11 includes the following process:

[0025] Heating stage: adjust the temperature to 860±5℃, keep warm for half an hour to reduce the temperature difference between the inside and outside of the workpiece;

[0026] Carburizing stage: the temperature is raised to 930±10℃, propane gas is filled in, and the temperature is kept for 1.12±0.1 hours to allow carbon atoms to penetrate into the surface of the workpiece and form a high carbon layer; the temperature is continued to be maintained at 930±10℃ and kept for 0.81±0.1 hours to make the carbon atoms evenly distributed;

[0027] Cooling stage: the temperature drops to 835±15℃ and is kept for half an hour to ensure that the workpiece temperature is uniform;

[0028] Quenching stage: Use quenching oil to quickly cool down to 110°C, so that the high carbon layer on the surface can be quickly cooled to form martensite;

[0029] Tempering stage: raise the temperature to 200±20℃ and maintain it for 150±30 minutes to eliminate quenching stress.

[0030] Furthermore, in step S11, before heat treatment, the workpiece needs to be cleaned and blocked at both ends, and an anti-hardening coating is applied to both end surfaces; after heat treatment, the surface hardness of the workpiece reaches HRC58-62, ensuring that the effective hardening layer depth is between 0.8 and 1.1 mm; shot blasting is performed to ensure that the outer circle runout of the workpiece does not exceed 0.3 mm.

[0031] The advantages of the present invention are: an integrated heat treatment carburizing and quenching method is adopted to improve the strength of the shaft, and sufficient toughness of the core is ensured under the premise that the surface has a sufficient hardened layer depth; the workpiece is heat treated and normalized after rough machining to eliminate stress, greatly reduce the heat treatment deformation, and make the part size more stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a process flow chart of a high-strength multi-section hollow spline shaft with internal oil passage in the embodiment;

[0033] Figure 2It is a heat treatment temperature variation curve diagram in the embodiment;

[0034] Figure 3 Schematic diagram of a high-strength multi-section hollow spline shaft with internal oil passage in an embodiment;

[0035] Figure 4 for Figure 3 A cross-sectional schematic diagram of

[0036] Description of symbols

[0037] 1. Through hole; 2. Radial oil hole. DETAILED DESCRIPTION

[0038] The present invention is further described in detail below in conjunction with the embodiments. It should be understood that the directions or positional relationships indicated by the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside" and "outside" herein are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention.

[0039] refer to Figures 1 to 3 This embodiment proposes a processing technology for a high-strength multi-section hollow spline shaft with an internal oil passage, comprising the following steps:

[0040] S01. The steel is cut by a circular saw to obtain a rod of a predetermined length and diameter;

[0041] S02. Turn the end face of the workpiece to make it smooth, ensure that the end face is perpendicular to the axis, turn a clamping area on the workpiece, and drill a center hole with a minor diameter of 5mm that meets the A-type standard at both ends of the workpiece;

[0042] S03. Use a fixture to hold one end of the workpiece, and use the tailstock top to support the center hole of the workpiece at the other end to ensure that the workpiece remains stable and accurately centered during processing;

[0043] The outer cylindrical end surface of one end of the workpiece is rough turned to a predetermined size, and a 2mm margin on one side of the outer circle is left for subsequent fine processing; the workpiece is removed, the direction is turned, the center hole is clamped and supported, and the outer cylindrical end surface of the other end of the workpiece is rough turned to a predetermined size, and a 2mm margin on one side of the outer circle is left for subsequent fine processing;

[0044] S04. Use a deep hole drill to drill a Φ22 through hole on the workpiece;

[0045] S05. Heat treat the workpiece to eliminate various stresses caused by rough machining;

[0046] S06. Make the end face of the workpiece smooth by turning or grinding to ensure that the end face is perpendicular to the axis of the workpiece. At the same time, cut the workpiece to the specified length according to the requirements of the design drawing;

[0047] Cut the two ends of the through hole of the workpiece to have a top positioning chamfer with an angle of 60° and a depth of 3mm;

[0048] S07. Use one end clamping and one end jacking to finish turning the outer cylindrical end face of one end of the workpiece, cut a groove at the specified position, and chamfer the processed edge. To facilitate subsequent processing, a single-side margin of 0.3-0.4mm needs to be reserved;

[0049] Turn the workpiece around, and use the same method of clamping at one end and pushing at the other end to finish turn the outer cylindrical end face of the other end of the workpiece, and chamfer the processed edge. In order to facilitate subsequent processing, a single-side margin of 0.3-0.4mm needs to be reserved;

[0050] S08. Roughly grind the outer circle to the predetermined size to serve as the alignment reference for the subsequent rolling of the rectangular spline;

[0051] S09. Select a spline hob according to the predetermined size and roll a 6-section rectangular spline;

[0052] S10. Drill a radial oil hole connected to the Φ22 through hole;

[0053] S11. Heat treatment;

[0054] S12. Repair the chamfering of the top holes at both ends of the workpiece;

[0055] S13. Use a grinder to fine-grind the outer diameter of the workpiece 5 sections;

[0056] S14. Clamp one end of the workpiece, use a center stand to hold the middle of the workpiece, drill and ream the holes at both ends of the workpiece to form Φ30 deep holes, of which the left hole is 364mm deep and the right hole is 300mm deep;

[0057] After completing the deep hole processing at both ends, the hole mouth is turned to form a socket hole;

[0058] Drill and tap M36×1.6 threads in the holes at both ends;

[0059] S15. The workpiece is ground into rectangular splines on a gear grinding machine, and the corresponding diamond roller is used to grind the grinding wheel to grind 6 splines;

[0060] S16. Final inspection of parts, using the chamfers at both ends as a reference to check whether all dimensions meet the standards;

[0061] S17. After the workpieces meet the inspection standards, they are cleaned, oiled and put into storage.

[0062] like Figure 2As shown, the heat treatment in step S11 includes the following stages:

[0063] 1. Heating stage: adjust the temperature to 860±5℃ and keep it warm for half an hour to reduce the temperature difference between the inside and outside of the workpiece to prevent deformation and cracking;

[0064] 2. Carburizing stage:

[0065] ① Strong penetration: the temperature is raised to 930±10℃, propane gas is filled in, and the temperature is kept for 1.12±0.1 hours to make carbon atoms penetrate into the surface of the workpiece to form a high carbon layer;

[0066] ② Diffusion: The temperature is maintained at 930±10℃ for 0.81±0.1 hours to make the carbon atoms evenly distributed on the surface of the workpiece to avoid excessive carbon concentration on the surface;

[0067] 3. Cooling stage: the temperature drops to 835±15℃ and is kept warm for half an hour to prepare for quenching and ensure that the workpiece temperature is uniform;

[0068] 4. Quenching stage: Use quenching oil to quickly cool down to 110°C, so that the high carbon layer on the surface of the workpiece can be quickly cooled to form martensite and increase the hardness;

[0069] 5. Tempering stage: raise the temperature to 200±20℃ and maintain it for 150±30 minutes to eliminate quenching stress, improve toughness and stabilize the structure.

[0070] Preferably, in step S11, before heat treatment, the workpiece needs to be cleaned to remove any oil, dust or other impurities, and after cleaning, both ends are blocked, and anti-hardening coatings (such as special anti-carburizing paste, alumina-based coatings, silicate coatings, etc.) are applied to both end surfaces to ensure that only the parts that need to be hardened are hardened, while the end faces and inner holes that do not need to be hardened will not be affected; after heat treatment, the surface hardness of the workpiece needs to reach HRC58-62 (Rockwell hardness), ensuring that the effective hardened layer depth is between 0.8 and 1.1 mm. After carburizing and quenching treatment, the workpiece usually deforms, so shot blasting is also performed after heat treatment to ensure that the outer circle of the workpiece does not exceed 0.3 mm, that is, the maximum offset of the outer circle relative to the ideal circle when the workpiece rotates does not exceed 0.3 mm.

[0071] The above embodiments are only used to explain the concept of the present invention, rather than to limit the protection of the rights of the present invention. Any non-substantial changes to the present invention using this concept shall fall within the protection scope of the present invention.

Claims

1. A processing technology for a high-strength multi-section hollow spline shaft with internal oil passage, characterized in that: The following steps are involved: S01. Cutting, obtaining rods of predetermined length and diameter; S02. Flatten the end surface, turn the clamping position, and drill the center holes at both ends; S03. Rough turning; S04. Drill through holes; S05. Normalizing to relieve stress; S06. Flat end surface, return to total length, turn the top positioning chamfer of the hole at both ends; S07. Finish turning the outer end surface, cutting grooves and chamfering; S08. Rough grinding of outer circle; S09. Knurled key; S10. Drill radial oil holes; S11. Heat treatment; S12. Repair the chamfering of the top of the holes at both ends; S13. Fine grinding of outer circle; S14. Drill, expand and ream the holes at both ends, and tap the threads; S15. Grinding splines; S16. After the inspection meets the standards, the products will be put into storage.

2. The processing technology of a high-strength multi-section hollow spline shaft with internal oil passage as claimed in claim 1 is characterized in that: The step S11 includes the following process: Heating stage: adjust the temperature to 860±5℃, keep warm for half an hour to reduce the temperature difference between the inside and outside of the workpiece; Carburizing stage: the temperature is raised to 930±10℃, propane gas is filled in, and the temperature is kept for 1.12±0.1 hours to allow carbon atoms to penetrate into the surface of the workpiece and form a high carbon layer; the temperature is continued to be maintained at 930±10℃ and kept for 0.81±0.1 hours to make the carbon atoms evenly distributed; Cooling stage: the temperature drops to 835±15℃ and is kept for half an hour to ensure that the workpiece temperature is uniform; Quenching stage: Use quenching oil to quickly cool down to 110°C, so that the high carbon layer on the surface can be quickly cooled to form martensite; Tempering stage: raise the temperature to 200±20℃ and maintain it for 150±30 minutes to eliminate quenching stress.

3. The processing technology of a high-strength multi-section hollow spline shaft with internal oil passage as claimed in claim 1 is characterized in that: In step S11, before heat treatment, the workpiece needs to be cleaned and blocked at both ends, and an anti-hardening coating is applied to both end surfaces; After heat treatment, the surface hardness of the workpiece reaches HRC58-62, ensuring that the effective hardened layer depth is between 0.8 and 1.1 mm; shot blasting is performed to ensure that the outer circle runout of the workpiece does not exceed 0.3 mm.

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