Machining method for input shaft of steering gear

Abstract

A processing method for an input shaft of a steering gear relates to the technical field of machining and comprises the following steps: S1, taking a solid quenched and tempered polished round bar as a blank; s2, roughly machining the outer circles and end faces of the two ends of the blank to obtain a crude product; s3, the crude product is ground for the first time, and a first machined part is obtained; s4, the first machined part is subjected to rolling machining, and an outer spline is formed; s5, finish milling machining is conducted on the plane appearance of the external spline, and a second machined part with a flat position is obtained; s6, electroplating treatment is conducted on the second machined part; s7, deep hole drilling is conducted on the second machined part, and a third machined part is obtained; s8, finish machining is conducted on the third machined part, and a fourth machined part is obtained; and S9, laser marking is conducted on the fourth machined part, and a steering gear input shaft finished product is obtained. By the adoption of the technical scheme, the problems that in the prior art, machining of an inner deep hole oil way of a solid bar is limited, and corrosion resistance is insufficient can be effectively solved.

Description

Technical Field

[0001] This invention relates to the field of machining technology, and specifically to a machining method for a steering gear input shaft. Background Technology

[0002] As the core transmission component of the electric power steering (EPS) system in automobiles, the steering input shaft's machining accuracy and reliability are of paramount importance.

[0003] To address the problems of lengthy processes and large circular runout values ​​of the input shaft produced by traditional tube shrinking processes, advanced processing methods, such as CN104439953B, have emerged. This method uses precision seamless steel tubes as blanks, forms the internal splines and various outer circle dimensions in one step through precision forging, and utilizes techniques such as center frame auxiliary positioning to process the reference, effectively improving the circular runout requirements of the bearing mounting surface and tapered surface, and shortening the processing steps.

[0004] However, the processing method proposed in CN104439953B is highly dependent on the specific premise of a hollow tube blank. This means that for input shaft products on the market that require manufacturing from solid bar stock and machining deep internal oil passages (such as oil passage holes and piston holes) from a solid state, this existing technology is unsuitable due to the inherent limitations of its process principle. The two differ fundamentally in terms of blank shape, processing difficulties, and technical routes. Furthermore, CN104439953B achieves rust prevention only through oil immersion after processing, and its corrosion resistance is insufficient to meet the stringent long-term rust prevention requirements of some customers for steering gear input shafts. Summary of the Invention

[0005] The purpose of this application is to provide a machining method for steering gear input shaft, which can effectively solve the limitations and insufficient corrosion resistance of machining deep hole oil passages in solid bar stock in the prior art.

[0006] The technical solution adopted in this invention is: a method for machining a steering gear input shaft, comprising the following steps: S1. Use solid tempered and polished round bars as raw materials and cut them into preset lengths to obtain billets; S2. Roughly machine the outer circles and end faces of the two ends of the blank to obtain a rough product; S3. The end faces of both ends of the rough product are ground for the first time to produce the first center hole and the second center hole, thus obtaining the first machined part; S4. Using the first center hole and the second center hole as a reference, roll the end of the first workpiece near the first center hole to form an external spline. S5. Perform precision milling on the planar shape of the external spline to obtain a second machined part with a flat section; S6. Electroplating zinc-nickel alloy onto the entire second workpiece; S7. Perform deep hole drilling on the second workpiece to machine the connected piston hole and oil passage hole, and obtain the third workpiece; S8. Perform finishing on the third workpiece to machine an inner hole, a first outer circle, a second outer circle, and an end face step on the third workpiece to obtain a fourth workpiece; S9. Laser mark the fourth processed part to form a traceability QR code on its surface to obtain the finished steering gear input shaft.

[0007] Optionally, between step S4 and step S5, step S41 is further included: using the first center hole and the second center hole as a reference, grinding is performed on the outer circles of both ends of the first workpiece.

[0008] Optionally, step S41 specifically includes: grinding the outer diameters of both ends of the first workpiece on a CNC cylindrical grinding machine to achieve the predetermined dimensional accuracy and coaxiality requirements.

[0009] Optionally, between step S6 and step S7, step S61 is further included: performing a second grinding on the first and second tip holes at both ends of the electroplated second workpiece.

[0010] Optionally, the solid tempered and polished round bar has a hardness of HRC22-28, a residual magnetic flux density of no more than 0.4 mT, and no surface deformation or cracks.

[0011] Optionally, in step S3, when the two end faces of the rough-machined blank are first ground by a CNC lathe, the first and second center holes are coaxially arranged and tapered holes with a cone angle of 60°.

[0012] Optionally, step S4 specifically includes: using a tooth rolling process, machining the external spline at the end of the first workpiece near the first center hole on a rolling mill; the tooth tip circle diameter of the external spline is Φ17.3mm, its machining length is 23.9mm, and the minimum distance between its end and the corresponding end face of the first workpiece is 6.1mm.

[0013] Optionally, step S6 specifically includes: using CNC precision milling technology to machine a first flat part and a second flat part on the outer circular surface of the tooth tip of the external spline; The first flat position is an anti-rotation plane parallel to the axis of the second workpiece, formed by milling the outer circular surface of the tooth tip. The second flat part is located on the side radially opposite to the first flat part. It is a concave part with a flat bottom, and the length direction of the concave part is perpendicular to the length direction of the first flat part.

[0014] Optionally, in step S9, the diameter of the piston hole is 9.0 mm and the diameter of the oil passage hole is 10.5 mm.

[0015] Optionally, step S10 specifically includes: machining the inner hole with a diameter of 14mm and the associated end face related to the inner hole by CNC precision turning; The third workpiece is ground using a CNC cylindrical grinding machine to produce the first outer circle and the second outer circle with diameters of 20 mm and 24 mm, respectively. The end face steps are then machined using CNC precision milling.

[0016] After adopting the above technical solution, the beneficial effects of the present invention are as follows: This application provides a method for machining a steering gear input shaft. Using a solid, heat-treated, polished round bar as raw material, and through a series of precision machining steps, including rough machining, first grinding of the center hole, rolling of the external spline, finish milling of the external spline plane, electroplating with zinc-nickel alloy, deep hole drilling, and final finishing and laser marking, this method successfully achieves precise machining of the deep-hole oil passages (such as oil passage holes and piston holes) inside the solid bar material, overcoming the limitations of traditional methods for this type of machining. Simultaneously, the overall electroplating with zinc-nickel alloy significantly improves the corrosion resistance of the steering gear input shaft, meeting the customer's stringent requirements for long-term rust prevention. Furthermore, the method features tight coordination between each step, high machining accuracy, and effectively improves production efficiency and product quality, providing a more reliable core transmission component solution for automotive electric power steering (EPS) systems. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a process flow diagram of the machining method for the steering gear input shaft provided in this embodiment; Figure 2 This is a diagram showing the blank in this embodiment; Figure 3 This is a diagram showing the crude product in this embodiment; Figure 4 This is a diagram showing the first processed part in this embodiment; Figure 5 This is a cross-sectional view of the first processed part in this embodiment; Figure 6 This is a diagram showing the external spline after it has been machined on the first workpiece in this embodiment; Figure 7 This is a diagram illustrating the second processed part in this embodiment; Figure 8 This is another perspective view of the second processed part in this embodiment; Figure 9 This is a diagram illustrating the third processed part in this embodiment; Figure 10 This is a cross-sectional view of the third processed part in this embodiment; Figure 11 This is a cross-sectional view of the third workpiece after the inner hole and the associated end face of the inner hole have been machined. Figure 12 This is a diagram illustrating the fourth processed part in this embodiment; Figure 13 This is a display diagram of the finished steering gear input shaft in this embodiment.

[0019] Explanation of reference numerals in the attached drawings: 100, blank; 200, rough product; 210, first center hole; 220, second center hole; 300, first machined part; 310, external spline; 400, second machined part; 410, piston hole; 420, oil passage hole; 430, first flat part; 440, second flat part; 500, third machined part; 510, inner hole; 511, associated end face; 520, first outer circle; 530, second outer circle; 540, end face step; 600, fourth machined part; 610, traceability QR code; 700, finished steering gear input shaft. Detailed Implementation

[0020] The following will refer to the appendices in the embodiments of the present invention. Figures 1-13 The technical solutions in the embodiments of the present invention are clearly and completely described herein. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0022] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, if the word "and / or" appears throughout the text, it means including three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution that simultaneously satisfies A and B. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0023] This embodiment provides a method for machining a steering gear input shaft, referring to... Figures 1-13 It includes the following steps: S1. Use solid tempered and polished round bars as raw materials and cut them into preset lengths to obtain billet 100; S2. Roughly machine the outer circles and end faces of both ends of the blank 100 to obtain a rough product 200; S3. The end faces of both ends of the rough product 200 are ground for the first time to process the first center hole 210 and the second center hole 220, and the first processed part 300 is obtained. S4. Using the first center hole 210 and the second center hole 220 as a reference, the end of the first workpiece 300 near the first center hole 210 is rolled to form an external spline 310. S5. Perform precision milling on the planar shape of the external spline 310 to obtain a second machined part 400 with a flat part; S6. Electroplating zinc-nickel alloy onto the entire second workpiece 400. S7. Deep hole drilling is performed on the second workpiece 400 to machine the connected piston hole 410 and oil passage hole 420 respectively, and the third workpiece 500 is obtained. S8. The third workpiece 500 is precision machined to machine an inner hole 510, a first outer circle 520, a second outer circle 530 and an end face step 540 on the third workpiece 500, to obtain a fourth workpiece 600. S9. Laser mark the fourth processed part 600 to form a traceability QR code 610 on its surface, and obtain the steering gear input shaft finished product 700.

[0024] Understandably, the processing method provided in this example, using solid tempered and polished round bars as raw materials, achieves precise machining of the deep-hole oil passages (such as oil passage holes 420 and piston holes 410) inside the solid bar stock through rough machining, first grinding of the center hole, rolling of the external spline 310, finish milling of the external spline 310 plane, electroplating with zinc-nickel alloy, deep hole drilling, and final finishing and laser marking. This solves the problem of the difficulty in precisely machining the deep-hole oil passages inside solid bar stock using existing technologies. At the same time, the overall electroplating with zinc-nickel alloy significantly improves the corrosion resistance of the steering gear input shaft, meeting the customer's stringent requirements for long-term rust prevention.

[0025] Furthermore, between step S4 and step S5, step S41 is also included: using the first center hole 210 and the second center hole 220 as a reference, the outer circles at both ends of the first workpiece 300 are ground.

[0026] Step S41 specifically includes: grinding the outer circles at both ends of the first workpiece 300 on a CNC cylindrical grinding machine to achieve the predetermined dimensional accuracy and coaxiality requirements of the outer circles at both ends.

[0027] Understandably, CNC cylindrical grinding machines are characterized by high precision and high automation, enabling them to precisely grind the outer diameters at both ends of the first workpiece 300 according to a preset program. Using the 60° tapered center hole as a positioning datum ensures the positioning accuracy and stability of the first workpiece 300 during the grinding process, thereby guaranteeing the dimensional accuracy and coaxiality of the outer diameters at both ends (dimensional accuracy and coaxiality directly affect the assembly accuracy and transmission performance of the steering gear input shaft and other components). In other words, through precise grinding, the outer diameters at both ends of the first workpiece 300 can meet design requirements, providing a solid foundation for subsequent machining and assembly.

[0028] Furthermore, between step S6 and step S7, step S61 is also included: performing a second grinding on the first tip hole 210 and the second tip hole 220 at both ends of the electroplated second workpiece 400.

[0029] Step S61 specifically includes: using a CNC lathe to perform a second grinding of the first center hole 210 and the second center hole 220 at both ends of the electroplated second workpiece 400 to ensure the machining accuracy of the first center hole 210 and the second center hole 220, so as to serve as a precise guide reference for subsequent deep hole drilling and other processes.

[0030] Understandably, the CNC lathe, according to a preset program, precisely controls the cutting tool to cut the first center hole 210 and the second center hole 220, removing factors that may affect accuracy, such as plating buildup and burrs, which may occur during the electroplating process, ensuring that the size, shape, and surface roughness of the center holes meet design requirements. After the second grinding, the first center hole 210 and the second center hole 220 can provide stable and accurate positioning for subsequent deep hole drilling, ensuring the machining accuracy of the piston hole 410 and oil passage hole 420 during deep hole drilling in step S7. This avoids problems such as skewness and dimensional deviations in deep hole drilling due to insufficient precision of the center holes, thereby ensuring the overall machining quality of the steering gear input shaft and meeting the high precision requirements of the automotive electric power steering system for core transmission components.

[0031] Furthermore, the solid tempered and polished round bar has a hardness of HRC22-28, and its residual magnetic flux density is no greater than 0.4mT, with no deformation or cracks on the surface.

[0032] Understandably, selecting solid tempered and polished round bars that meet the above conditions as raw materials can ensure the machining quality of the steering gear input shaft from the source. A hardness between HRC22 and 28 ensures that the raw material has sufficient strength to withstand various stresses during subsequent processing, while also possessing a certain degree of toughness to prevent brittle fracture during machining; a residual magnetic flux density of no more than 0.4 mT prevents the magnetic adsorption of impurities such as iron filings during processing, thus ensuring machining accuracy and surface quality; and the absence of cracks on the surface of the solid tempered and polished round bar guarantees the performance of the final product.

[0033] In actual production, demagnetization treatment can be used to ensure that the residual magnetic flux density of solid quenched and tempered polished round bars is no greater than 0.4 mT. At the same time, 100% non-destructive testing can be used to ensure that the surface of solid quenched and tempered polished round bars is free of defects such as cracks and deformation.

[0034] In this embodiment, the length of the blank 100100 is 227±0.5mm and the diameter is 25±0.02mm.

[0035] Further, step S2 specifically includes: clamping the blank 100 on a CNC lathe, rotating the blank 100 by the lathe spindle, and simultaneously using a cutting tool to rough machine (cutting) the outer diameter and end face of both ends of the blank 100. During machining, one end of the blank 100 is rough machined first, and then the other end of the blank 100 is rough machined to ensure the symmetry and accuracy of the machining at both ends.

[0036] It is understandable that rough machining of the outer circles and end faces at both ends of the blank 100 is to remove defects such as oxide layer and rust from the surface of the raw material, and at the same time to provide an accurate positioning reference for subsequent processing, so that the outer circles and end faces at both ends of the blank 100 meet the size and shape requirements of the initial steering gear input shaft, that is, to obtain the rough product 200, which is convenient for subsequent operations such as grinding of the center hole.

[0037] Furthermore, in step S3, when the two end faces of the rough-machined blank 100 are first ground by a CNC lathe, the first center hole 210 and the second center hole 220 are coaxially arranged and are tapered holes with a cone angle of 60°.

[0038] Understandably, the first grinding of the end faces of the blank 100 is to further correct any dimensional deviations and shape errors that may exist after rough machining, ensuring the flatness and perpendicularity of the end faces, and providing a good foundation for the subsequent precise machining of the center holes. The first center hole 210 and the second center hole 220 adopt a coaxial, tapered hole design with a 60° taper angle. This ensures that the workpiece can be stably mounted between the centers during subsequent machining. The tight fit of the tapered surfaces achieves precise positioning and support, avoiding machining errors caused by inaccurate positioning and improving machining stability and accuracy. During the grinding process, the CNC lathe can precisely control the tool's movement trajectory and cutting parameters according to a preset program, ensuring that the coaxiality, taper angle, and surface quality of the two center holes meet the design requirements.

[0039] Further, step S4 specifically includes: using a tooth rolling process, machining the external spline 310 on one end of the first workpiece 300 on a rolling mill; the tooth tip circle diameter of the external spline 310 is Φ17.3mm, its machining length is 23.9mm, and the minimum distance between its end and the corresponding end face of the first workpiece 300 is 6.1mm.

[0040] Understandably, gear rolling is a highly efficient and precise method for machining external splines 310. Through the relative movement between the gear rolling plate on the rolling mill and the first workpiece 300, the metal surface of the first workpiece 300 undergoes plastic deformation, thereby forming the desired external spline 310 shape. This process has advantages such as high processing efficiency, high material utilization, and stable machining accuracy. By controlling parameters such as the tooth tip circle diameter, machining length, and minimum distance from the end to the corresponding end face of the external spline 310, the dimensional and shape accuracy of the external spline 310 can be ensured, meeting the assembly requirements of the steering gear input shaft and other components, and guaranteeing the normal operation of the transmission system.

[0041] Further, step S5 includes: using CNC precision milling technology to machine a first flat portion 430 and a second flat portion 440 on the outer circular surface of the tooth tip of the external spline 310; The first flat part 430 is an anti-rotation plane parallel to the axis of the second workpiece 400, formed by milling the outer circular surface of the tooth tip; the second flat part 440 is located on the side radially opposite to the first flat part 430, and is a concave part with a flat bottom, and the length direction of the concave part is perpendicular to the length direction of the first flat part 430.

[0042] CNC precision milling enables high-precision machining of complex shapes. By precisely controlling the movement trajectory and cutting parameters of the milling cutter, a first flat portion 430 and a second flat portion 440 are machined on the outer cylindrical surface of the tooth tip of the external spline 310. The first flat portion 430 serves as an anti-rotation plane, preventing the steering gear input shaft from rotating during assembly or use, thus ensuring transmission stability. The design of the second flat portion 440 can provide a specific structural shape for the installation or connection of other components according to actual usage requirements, meeting different assembly needs.

[0043] Furthermore, before performing step S7 (overall electroplating) on ​​the second workpiece 400, the first and second tip holes 210 and 220 can be protected (or left unprotected, in which case they will be re-ground in subsequent step S61). This prevents the first and second tip holes 210 and 220 from being corroded by chemicals during the electroplating process, thus ensuring their accuracy and performance. Specifically, a special plug can be used to seal the first and second tip holes 210 and 220. The plug material should have good chemical corrosion resistance and fit tightly with the dimensions of the first and second tip holes 210 and 220 to ensure that it does not fall off or seep into the electroplating solution.

[0044] Furthermore, in step S7: the diameter of the piston hole 410 is 9.0 mm, and the diameter of the oil passage hole 420 is 10.5 mm.

[0045] The hydraulic manifold 420 is the channel for hydraulic oil flow. Its diameter directly affects the flow rate and velocity of the hydraulic oil, thus influencing the steering system's response speed and power assist effect. The piston manifold 410 is the component that mounts the piston. Its diameter needs to be precisely matched with the piston's dimensions to ensure smooth piston movement within the manifold, good sealing, prevention of hydraulic oil leakage, and ensure the normal operation of the hydraulic system. By using deep hole drilling technology and strictly controlling the drilled diameter, the design requirements of the steering input shaft for the piston manifold 410 and hydraulic manifold 420 can be met.

[0046] Further, step S8 specifically includes: machining the inner hole 510 with a diameter of 14mm and the associated end face 511 related to the inner hole 510 by CNC precision turning; The third workpiece 500 is ground using a CNC cylindrical grinding machine to produce the first outer circle 520 and the second outer circle 530 with diameters of 20 mm and 24 mm, respectively. The end face step 540 is machined by CNC precision milling.

[0047] In this embodiment, the inner hole 510 and the associated end face 511 related to the inner hole 510 are both deep-hole drilled based on the oil passage hole 420 in step S7. The first outer circle 520 and the second outer circle 530 are both located on the surface of the third workpiece 500. The second outer circle 530 is located at the end of the third workpiece 500 near the oil passage hole 420, and the end face step 540 is located between the second outer circle 530 and the end face of the third workpiece 500.

[0048] Understandably, high-precision machining equipment such as CNC precision turning, CNC precision milling, and CNC cylindrical grinding machines are used to machine key dimensions such as the inner hole 510, the first outer circle 520, the second outer circle 530, and the end face step 540 on the third machining part 500. Among them, the precise machining of the inner hole 510 ensures the fitting accuracy with other related components, ensuring the smooth flow of hydraulic oil and other media, and providing a basic guarantee for the stable operation of the steering system. The machining accuracy of the end face 511 associated with the inner hole 510 affects the sealing and connection reliability of the entire component, avoiding problems such as leakage. The dimensional accuracy of the first outer circle 520 and the second outer circle 530 is directly related to the assembly effect of the steering input shaft with other mechanical components. If the dimensional deviation is too large, it may lead to assembly difficulties, or even abnormal wear and vibration during operation, affecting the normal operation and service life of the steering system. The machining accuracy of the end face step 540 is also crucial for the positioning and connection of components. A precise end face step 540 can ensure the accurate position of the steering gear input shaft in the overall structure, making the force transmission between components more uniform and stable.

[0049] Further, step S9 specifically includes: using a laser marking machine to laser-engrave a traceability QR code 610 at a preset position on the fourth processed part 600 to improve the traceability of the product and obtain the finished steering input shaft 700.

[0050] In this embodiment, the traceability QR code 610 contains product information, such as production batch, production date, raw material source, and processing parameters. During the product manufacturing process, by scanning the traceability QR code 610, the company can quickly obtain detailed production records, facilitating monitoring and management of the production process and timely identification and resolution of potential quality issues. After the product is delivered and put into use, when quality problems arise or maintenance is required, repair personnel or customers can scan the traceability QR code 610 to quickly understand relevant product information, determine the root cause of the problem, and take targeted solutions. This not only helps improve product quality and customer satisfaction but also provides the company with valuable product usage data, providing a basis for product improvement and optimization, and further enhancing the company's market competitiveness.

[0051] Working Principle: First, a solid, tempered, and polished round bar meeting specific conditions (hardness, non-destructive testing, demagnetization, etc.) is selected as the raw material to ensure processing quality from the source. Next, the blank 100 is rough-machined to remove surface defects and provide a positioning reference for subsequent processing, resulting in a rough product 200. Then, the end faces of the rough product 200 are first-time ground to correct dimensional deviations and shape errors, laying the foundation for precise machining of the center holes. Simultaneously, coaxial conical center holes with a 60° cone angle (i.e., the first center hole 210 and the second center hole 220) are machined to ensure stable installation and precise positioning of the workpiece during subsequent processing. Afterwards, the external spline 310 is machined using a gear-rolling process, utilizing the plastic deformation of the metal to form the required shape, ensuring that the dimensional and shape accuracy meets assembly requirements. Using the 60° conical center hole as a positioning reference, the outer diameters at both ends are ground on a CNC cylindrical grinding machine to achieve the predetermined dimensional accuracy and coaxiality requirements, providing a good foundation for subsequent processing and assembly. The first flat portion 430 and the second flat portion 440 are then machined using CNC precision milling to meet anti-rotation and specific assembly requirements. Before electroplating the second workpiece 400 as a whole, the center holes can be protected to prevent electroplating corrosion. After electroplating, the first center holes 210 and the second center holes 220 at both ends of the electroplated second workpiece 400 are re-ground using a CNC lathe to remove factors affecting accuracy and provide a precise guiding reference for deep hole drilling. During deep hole drilling, the diameter dimensions of the piston hole 410 and the oil passage hole 420 are strictly controlled to meet design requirements. Then, using high-precision machining equipment such as CNC precision turning, CNC cylindrical grinding, and CNC precision milling, key dimensions such as the inner hole 510, the first outer diameter 520, the second outer diameter 530, and the end face step 540 are machined on the third workpiece 500 to ensure the machining accuracy of each part, ensuring stable operation of the steering system, good assembly effect, and accurate positioning connection. Finally, a traceability QR code 610 is laser-engraved at a preset position on the fourth processed part 600 using a laser marking machine. This improves product traceability, facilitates enterprise monitoring and management of the production process, and allows maintenance personnel and customers to understand product information. It also provides a basis for enterprise product improvement and optimization, thereby enhancing market competitiveness.

[0052] The above is only used to illustrate the technical solution of the present invention and is not intended to limit it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention, as long as they do not depart from the spirit and scope of the technical solution of the present invention, should be covered within the scope of the claims of the present invention.

Claims

1. A method for machining a steering gear input shaft, characterized in that, Includes the following steps: S1. Take a solid tempered and polished round bar as raw material and cut it into a preset length to obtain a blank (100); S2. Roughly machine the outer circles and end faces of both ends of the blank (100) to obtain a rough product (200); S3. The end faces of both ends of the rough product (200) are ground for the first time to process the first center hole (210) and the second center hole (220) to obtain the first processed part (300). S4. Using the first center hole (210) and the second center hole (220) as references, roll the end of the first workpiece (300) near the first center hole (210) to form an external spline (310); S5. Perform precision milling on the planar shape of the external spline (310) to obtain a second machined part (400) with a flat part; S6. The second workpiece (400) is subjected to electroplating zinc-nickel alloy treatment. S7. Deep hole drilling is performed on the second workpiece (400) to machine the connected piston hole (410) and oil passage hole (420) respectively, and the third workpiece (500) is obtained. S8. The third workpiece (500) is precision machined to machine an inner hole (510), a first outer circle (520), a second outer circle (530) and an end face step (540) on the third workpiece (500) to obtain a fourth workpiece (600). S9. Laser mark the fourth processed part (600) to form a traceability QR code (610) on its surface, and obtain the finished steering input shaft (700).

2. The machining method for the steering gear input shaft according to claim 1, characterized in that, Between step S4 and step S5, there is also step S41: using the first center hole (210) and the second center hole (220) as references, the outer circles of both ends of the first workpiece (300) are ground.

3. The machining method for the steering gear input shaft according to claim 2, characterized in that, Step S41 specifically includes: grinding the outer circles at both ends of the first workpiece (300) on a CNC cylindrical grinding machine to achieve the predetermined dimensional accuracy and coaxiality requirements of the outer circles at both ends.

4. The machining method for the steering gear input shaft according to claim 1, characterized in that, Between step S6 and step S7, step S61 is also included: a second grinding is performed on the first tip hole (210) and the second tip hole (220) at both ends of the electroplated second workpiece (400).

5. The machining method for the steering gear input shaft according to claim 1, characterized in that, The solid tempered and polished round bar has a hardness of HRC22-28, and its residual magnetic flux density is no greater than 0.4mT. The surface is free of deformation and cracks.

6. The machining method for the steering gear input shaft according to claim 1, characterized in that, In step S3, when the two end faces of the rough-machined blank (100) are first ground by a CNC lathe, the first center hole (210) and the second center hole (220) are coaxially arranged and tapered holes with a cone angle of 60°.

7. The machining method for the steering gear input shaft according to claim 1, characterized in that, Step S4 specifically includes: using a tooth rolling process, the external spline (310) is formed on the end of the first workpiece (300) near the first center hole (210) on a rolling mill; the tooth tip circle diameter of the external spline (310) is Φ17.3mm, its processing length is 23.9mm, and the minimum distance between its end and the corresponding end face of the first workpiece (300) is 6.1mm.

8. The machining method for the steering gear input shaft according to claim 1, characterized in that, Step S6 specifically includes: using CNC precision milling technology to machine the first flat part (310) and the second flat part (320) on the outer circle surface of the tooth tip of the external spline (310); Wherein, the first flat part (310) is an anti-rotation plane parallel to the axis of the second workpiece (400) formed by milling the outer circular surface of the tooth tip; The second flat part (320) is located on the side radially opposite to the first flat part (310), and it is a concave part with a flat bottom, and the length direction of the concave part is perpendicular to the length direction of the first flat part (310).

9. The machining method for the steering gear input shaft according to claim 1, characterized in that, In step S9, the diameter of the piston hole (410) is 9.0 mm, and the diameter of the oil passage hole (420) is 10.5 mm.

10. The machining method for the steering gear input shaft according to claim 1, characterized in that, Step S10 specifically includes: machining the inner hole (510) with a diameter of 14mm and the associated end face (511) related to the inner hole (510) by CNC precision turning; The third workpiece (500) is ground by a CNC cylindrical grinding machine to produce the first outer circle (520) and the second outer circle (530) with diameters of 20 mm and 24 mm respectively. The end face step (540) is machined by CNC precision milling.

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