Method for machining bearing holes of light metal intake manifolds

Abstract

The application discloses a processing method of a bearing hole of a light metal intake casing, which comprises the following steps: setting an annular groove to accommodate a wear-resistant coating, so that a mechanical anchoring structure is formed between the wear-resistant coating and the inner wall base body of the bottom hole; when a tool simultaneously cuts the inner wall base body of the bottom hole and the coating blank, stress is avoided from being concentrated at the bonding surface of the wear-resistant coating and the inner wall base body of the bottom hole through the annular groove, and the risk of the wear-resistant coating being bulged or even falling off from the bonding surface is significantly reduced; in addition, the annular groove effectively anchors the wear-resistant coating during the processing stage, and the falling-off hidden danger of the wear-resistant coating during the service process is solved from the root; during the cutting processing, the size precision of the finished product bearing hole is accurately controlled, the integrity of the wear-resistant coating is not damaged by the annular groove, and subsequent rework is not needed, so that the qualified rate of the bearing hole is high, and the processing cycle is short; the bearing is supported by the wear-resistant coating, so that reliable support of the bearing is realized while the lightweight design of the intake casing is met, the practicality is high, and the method is suitable for being widely promoted and applied.

Description

Technical Field

[0001] This invention relates to the field of parts cutting and machining technology, and in particular, to a method for machining bearing holes in a light metal intake casing. Background Technology

[0002] The air intake casing is one of the key core components of an aero-engine. Installed at the very front of the engine, it plays a crucial role in the engine's overall performance, reliability, and structural integrity. To meet the requirements of lightweight design and improve performance, the air intake casing is typically made of lightweight metals such as aluminum-magnesium alloys and manufactured using a monolithic casting process. The bearing bore at the center of the air intake casing's axis is the absolute positioning reference and load-bearing intersection point for the engine's stator and rotor systems. It is one of the most critical fitting features in the entire engine structure, requiring a bore diameter accuracy of IT7 or higher and a surface roughness Ra ≤ 1.6 μm. This bearing bore is used to install bearings, but because its bore wall base material is aluminum-magnesium alloy, and the coefficient of thermal expansion of aluminum-magnesium alloy is approximately twice that of bearing steel, during aero-engine operation, the temperature rises, and the thermal expansion of the bearing bore exceeds that of the bearing itself. This can easily cause the bearing to lose reliable radial support, leading to serious safety issues. Therefore, in order to improve the strength and wear resistance of the bearing bore in the aluminum-magnesium alloy intake casing, a spraying process is usually adopted to spray a certain thickness of wear-resistant coating such as nickel-chromium aluminum-magnesium alloy onto the inner surface of the bearing bore, so as to improve the strength and wear resistance of the bearing bore wall.

[0003] Currently, there are two main methods for machining the bearing bores of light metal intake casings: The first approach involves drilling holes to form bearing bores, then spraying a wear-resistant coating onto the inner surface of the bearing bores, and finally machining. However, this approach has the following problems in practical applications: due to the high strength and toughness of the wear-resistant coating (such as nickel-chromium-aluminum-magnesium alloy), the cutting tool wears quickly and the risk of chipping is high during machining, significantly increasing processing costs; at the same time, the bonding strength between the coating and the substrate of the bearing bore wall is insufficient, and under the action of cutting force and cutting heat, the coating is prone to bulging or even falling off from the bonding surface, resulting in a low part quality rate and a high rework rate.

[0004] The second approach involves first drilling holes to form bearing holes, then alternating between coating preparation and machining (i.e., a multi-cycle process of "spraying-machining-re-spraying-re-machining"). While this approach improves the coating adhesion problem to some extent, the process steps are cumbersome and complex, and the multiple clamping and alignment operations significantly extend the processing cycle, resulting in low production efficiency and making it difficult to meet the needs of mass production.

[0005] In summary, existing methods for machining bearing holes in light metal intake casings cannot simultaneously meet the requirements of coating adhesion strength, machining accuracy, and machining efficiency. There is an urgent need to develop a bearing hole machining method that can achieve high-precision and high-efficiency machining while ensuring strong coating adhesion. Summary of the Invention

[0006] This invention provides a method for processing bearing holes in light metal intake casings, in order to solve the technical problems of low pass rate and high rework rate caused by easy bulging and peeling of coatings in existing processing of bearing holes in light metal intake casings, or long processing cycle caused by complicated process steps.

[0007] According to one aspect of the present invention, a method for processing a bearing hole in a light metal intake casing is provided, comprising the following steps: S1: drilling a bottom hole to form the bearing hole at the axial center of the intake casing; S2: processing at least one annular groove on the inner wall of the bottom hole and corresponding to the bearing mounting position, the annular groove being used to accommodate the sprayed wear-resistant coating to support the bearing through the wear-resistant coating; S3: spraying the wear-resistant coating into the annular groove until the annular groove is filled, forming a coating blank covering the inner surface of the annular groove and at least part of the inner wall of the bottom hole; S4: machining the inner surface of the bearing hole after spraying, while removing excess material from the substrate of the inner wall of the bottom hole and the coating blank, so that the diameter accuracy and surface roughness of the bearing hole meet the set requirements, and obtaining a finished product whose inner surface is composed of the substrate of the inner wall of the bottom hole and the wear-resistant coating filled in the annular groove.

[0008] As a further improvement to the above technical solution: Furthermore, in step S4, the cutting process includes a rough boring process, a semi-finish boring process, and a finish boring process performed sequentially, with the cutting speed and feed rate decreasing sequentially in the rough boring process, the semi-finish boring process, and the finish boring process.

[0009] Furthermore, the rough boring process has the following parameters: cutting speed 250r / min-300r / min, feed rate 15mm / min-18mm / min; semi-finish boring process has the following parameters: cutting speed 200r / min-250r / min, feed rate 12mm / min-15mm / min; and finish boring process has the following parameters: cutting speed 180r / min-200r / min, feed rate 10mm / min-12mm / min.

[0010] Furthermore, in the precision boring process, the machining amount of the last pass is 0.1mm.

[0011] Furthermore, after the rough boring process is completed, the cutting allowance reserved for the subsequent semi-finish boring process is 0.4mm-0.6mm; after the semi-finish boring process is completed, the cutting allowance reserved for the subsequent finish boring process is 0.15mm-0.25mm.

[0012] Furthermore, diamond tools are used for rough boring, semi-finish boring, and finish boring processes.

[0013] Furthermore, the rough boring, semi-finish boring, and finish boring processes all use an emulsion with a mass concentration of 8% to 12% as the cutting fluid.

[0014] Furthermore, in step S2, when machining the annular groove, the inner surface roughness of the annular groove is made to reach a preset value by increasing the feed rate and reducing the cutting speed, so as to increase the bonding strength between the substrate of the bottom hole inner wall and the wear-resistant coating.

[0015] Furthermore, in step S2, the cross-sectional shape of the annular groove is a dovetail groove or a trapezoidal groove.

[0016] Furthermore, in step S2, the annular groove being processed is one or more.

[0017] The present invention has the following beneficial effects: The present invention discloses a method for processing a bearing hole in a lightweight metal intake casing. First, a bottom hole for the bearing hole is drilled at the center of the intake casing's axis, serving as the basis for subsequent processing. Then, at least one annular groove is machined on the inner wall of the bottom hole, corresponding to the bearing mounting position. Next, a wear-resistant coating is sprayed into the annular groove until it is completely filled, forming a coating blank covering the inner surface of the annular groove and at least part of the inner wall of the bottom hole. Finally, the inner surface of the bearing hole after spraying is machined, removing excess material from the bottom hole inner wall substrate and the coating blank, ensuring that the dimensional accuracy and surface roughness of the bearing hole meet the set requirements. This yields a finished bearing hole whose inner surface is composed of the bottom hole inner wall substrate and the wear-resistant coating filled in the annular groove. This design utilizes an annular groove to accommodate the wear-resistant coating, creating a mechanical anchoring structure between the coating and the substrate inside the bottom hole. During subsequent machining, when the tool simultaneously cuts both the substrate and the coated blank, the groove wall provides lateral support to the coating, while the groove bottom provides axial restraint. This combined effect prevents stress concentration at the interface between the wear-resistant coating and the substrate, significantly reducing the risk of bulging or even detachment of the coating. Furthermore, the annular groove effectively anchors the wear-resistant coating during machining, preventing the accumulation of machining damage and addressing the root cause of the problem. This significantly improves the bonding reliability between the wear-resistant coating and the substrate on the inner wall of the bottom hole under long-term alternating loads and thermal cycling, fundamentally solving the potential problem of wear-resistant coating peeling off during service. During machining, by simultaneously finishing the substrate on the inner wall of the bottom hole and the wear-resistant coating, the dimensional accuracy of the finished bearing hole can be precisely controlled. The annular groove ensures that the integrity of the wear-resistant coating is not damaged, eliminating the need for subsequent rework, resulting in a high pass rate for the bearing hole and a short processing cycle. By using the wear-resistant coating to support the bearing, reliable support for the bearing can be achieved while meeting the lightweight design requirements of the intake casing. This approach is highly practical and suitable for widespread promotion and application.

[0018] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0019] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a flowchart illustrating the steps of a preferred embodiment of the present invention for processing a bearing hole in a light metal intake casing. Detailed Implementation

[0020] The following description provides specific application scenarios and requirements for this specification, intended to enable those skilled in the art to make and use the contents of this specification. Various partial modifications to the disclosed embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments and applications without departing from the spirit and scope of this specification.

[0021] The terminology used herein is for the purpose of describing particular exemplary embodiments only and is not restrictive. For example, unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” as used herein may also include the plural forms. When used in this specification, the terms “comprising,” “including,” and / or “containing” mean that the associated integers, steps, operations, elements, and / or components are present, but do not preclude the presence of one or more other features, integers, steps, operations, elements, components, and / or groups, or that other features, integers, steps, operations, elements, components, and / or groups may be added to the system / method.

[0022] Considering the following description, these and other features of this specification, as well as the operation and function of the related components of the structure, and the economy of assembly and manufacture of the parts, can be significantly improved. All of these form part of this specification with reference to the accompanying drawings. However, it should be clearly understood that the drawings are for illustrative and descriptive purposes only and are not intended to limit the scope of this specification. It should also be understood that the drawings are not drawn to scale.

[0023] like Figure 1As shown, the processing method of the bearing hole of the light metal intake casing in this embodiment includes the following steps: S1: Drilling a bottom hole to form the bearing hole at the center of the intake casing axis; S2: Processing at least one annular groove on the inner wall of the bottom hole and corresponding to the bearing installation position, the annular groove is used to accommodate the sprayed wear-resistant coating to support the bearing through the wear-resistant coating; S3: Spraying the wear-resistant coating into the annular groove until the annular groove is filled, forming a coating blank covering the inner surface of the annular groove and at least part of the inner wall of the bottom hole; S4: Cutting the inner surface of the bearing hole after spraying, and removing excess material from the substrate of the inner wall of the bottom hole and the coating blank, so that the diameter accuracy and surface roughness of the bearing hole meet the set requirements, and obtaining a finished product whose inner surface is composed of the substrate of the inner wall of the bottom hole and the wear-resistant coating filled in the annular groove.

[0024] Specifically, the processing method for the bearing hole of the light metal intake casing of the present invention firstly drills a bottom hole at the center of the axis of the intake casing to form the bearing hole, which serves as the basis for subsequent processing; then, at least one annular groove is processed on the inner wall of the bottom hole, corresponding to the bearing installation position; then, a wear-resistant coating is sprayed into the annular groove until it is filled, forming a coating blank covering the inner surface of the annular groove and at least part of the inner wall of the bottom hole; finally, the inner surface of the bearing hole after spraying is machined, and excess material of the substrate of the inner wall of the bottom hole and the coating blank is removed, so that the dimensional accuracy and surface roughness of the bearing hole meet the set requirements, and a finished bearing hole is obtained whose inner surface is composed of the substrate of the inner wall of the bottom hole and the wear-resistant coating filled in the annular groove. This design utilizes an annular groove to accommodate the wear-resistant coating, creating a mechanical anchoring structure between the coating and the substrate inside the borehole. During subsequent machining, when the tool simultaneously cuts both the borehole substrate and the coated blank, the groove wall provides lateral support to the coating, while the groove bottom provides axial constraint. This combined effect prevents stress concentration at the interface between the wear-resistant coating and the borehole substrate, significantly reducing the risk of bulging or even detachment of the coating. Furthermore, the annular groove effectively anchors the wear-resistant coating during machining, preventing the accumulation of machining damage. This technology fundamentally improves the bonding reliability between the wear-resistant coating and the substrate on the inner wall of the bottom hole under long-term alternating loads and thermal cycling, thus eliminating the risk of peeling off the wear-resistant coating during service. During machining, the dimensional accuracy of the finished bearing hole is precisely controlled by simultaneously trimming the substrate on the inner wall of the bottom hole and the wear-resistant coating. The annular groove ensures that the integrity of the wear-resistant coating is not damaged, eliminating the need for subsequent rework and resulting in a high pass rate for the bearing hole and a short processing cycle. By using the wear-resistant coating to support the bearing, reliable support for the bearing is achieved while meeting the lightweight design requirements of the intake casing. This technology is highly practical and suitable for widespread promotion and application.

[0025] Alternatively, the light metals include aluminum-magnesium alloys, aluminum-lithium alloys, and titanium alloys.

[0026] Alternatively, the wear-resistant coating may include an MCrAlY system layer, a ceramic coating, or a metal-ceramic composite coating.

[0027] It should be understood that this solution is applicable not only to the intake casing but also to the machining of bearing holes in other housing-type parts.

[0028] In this embodiment, step S4 includes a rough boring process, a semi-finish boring process, and a finish boring process performed sequentially, with the cutting speed and feed rate decreasing sequentially in the rough boring process, the semi-finish boring process, and the finish boring process. Specifically, the rough boring process first efficiently removes most of the excess material using relatively high cutting speeds and feed rates, laying the foundation for subsequent machining. Compared to the rough boring process, the semi-finish boring process reduces both cutting speed and feed rate, which helps to reduce cutting forces, correct potential shape errors after rough boring, and avoids additional stress on the coating bonding surface during finishing, while also creating uniform allowance conditions for finish boring. The finish boring process uses the lowest cutting speed and feed rate, which helps to ensure the dimensional accuracy and surface roughness of the finished bearing hole. The low cutting speed also reduces cutting heat, preventing thermal damage that could lead to a decrease in the bonding force between the coating and the substrate on the inner wall of the bottom hole. The decreasing cutting parameters ensure a smooth transition in the machining process, preventing coating peeling caused by sudden changes in cutting force. In addition, the annular groove anchors the coating macroscopically through mechanical interlocking, while the decreasing cutting parameters microscopically prevent stress concentration during machining. Together, these two processes fundamentally solve the problem of coating bulging and peeling off from the bonding surface during machining.

[0029] In this embodiment, the rough boring process has a cutting speed of 250 r / min-300 r / min and a feed rate of 15 mm / min-18 mm / min. Specifically, when the cutting speed of the rough boring process is between 250 r / min and 300 r / min and the feed rate is between 15 mm / min and 18 mm / min, the rough boring can remove the allowance with high efficiency while ensuring that the cutting force does not exceed the bearing limit of the coating interface. If the cutting speed is less than 250 r / min or the feed rate is less than 15 mm / min, cutting vibration is likely to occur, affecting the machining stability. If the cutting speed is greater than 300 r / min or the feed rate is greater than 18 mm / min, it may lead to excessive cutting heat and excessive cutting force, which will have an adverse effect on the coating bonding strength.

[0030] In this embodiment, the semi-finish boring process has a cutting speed of 200 r / min-250 r / min and a feed rate of 12 mm / min-15 mm / min. Specifically, when the cutting speed of the semi-finish boring process is between 200 r / min and 250 r / min and the feed rate is between 12 mm / min and 15 mm / min, the cutting force of the semi-finish boring is reduced, which can effectively correct the roundness error that may exist after rough boring. At the same time, it avoids stress concentration at the interface between the coating and the substrate due to the fluctuation of cutting force, and can also improve the surface quality, creating good machining conditions for finish boring. If the cutting speed is less than 200 r / min or the feed rate is less than 12 mm / min, built-up edge is easily generated, which aggravates tool wear and cannot effectively correct shape errors. If the cutting speed is greater than 250 r / min or the feed rate is greater than 15 mm / min, it may lead to excessive cutting heat, causing thermal damage to the coating.

[0031] In this embodiment, the precision boring process has a cutting speed of 180 r / min-200 r / min and a feed rate of 10 mm / min-12 mm / min. Specifically, when the cutting speed of the precision boring process is between 180 r / min and 200 r / min and the feed rate is between 10 mm / min and 12 mm / min, it is beneficial to ensure the final dimensional accuracy and surface quality of the bearing hole, minimize the cutting force, strictly control the cutting temperature, maximize the protection of the coating integrity, achieve stable cutting, and avoid impact loads. If the cutting speed is less than 180 r / min, built-up edge is easily generated, and the machining efficiency is low. If the cutting speed is greater than 200 r / min, the cutting temperature is relatively high, and the risk of vibration increases. If the feed rate is less than 10 mm / min, the cutting thickness may be less than the tool cutting edge radius, resulting in a "squeeze-slip" phenomenon. The contact time between the tool and the workpiece is prolonged, which leads to local temperature rise and low machining efficiency. If the feed rate is greater than 12 mm / min, the surface roughness increases, the cutting force increases, and it is not conducive to ensuring dimensional accuracy and surface quality. In this embodiment, the machining amount of the last pass in the precision boring process is 0.1 mm.

[0032] In this embodiment, during the precision boring process, the machining amount of the last pass is 0.1mm. This micro-cutting of 0.1mm allows the tool to precisely control the hole diameter under extremely low cutting load, ensuring the final dimensional accuracy, obtaining ideal surface quality, maximizing the protection of coating integrity, and effectively removing any minor defects left over from previous processes, thus ensuring the integrity and consistency of the finished hole.

[0033] In this embodiment, after the rough boring process, a cutting allowance of 0.4mm-0.6mm is reserved for the subsequent semi-finish boring process. This ensures that the semi-finish boring process has sufficient material removal to correct errors and avoids excessive cutting load. It also provides space for the selection of cutting parameters for the semi-finish boring process, allowing for flexible adjustment of the number of passes or the depth of cut according to actual working conditions. After the semi-finish boring process, a cutting allowance of 0.15mm-0.25mm is reserved for the subsequent finish boring process. This ensures that the finish boring process has sufficient material removal to eliminate tool marks from the semi-finish boring process and avoids excessive cutting load. It also provides sufficient adjustment space for the finish boring process, ensuring the stability of the final dimensional accuracy.

[0034] Preferably, in one embodiment, the machining parameters are as follows: for rough boring, the cutting speed is 300 r / min and the feed rate is 18 mm / min, and the cutting allowance reserved for the subsequent semi-finish boring process after the rough boring process is 0.5 mm; for semi-finish boring, the cutting speed is 200 r / min and the feed rate is 15 mm / min, and the cutting allowance reserved for the subsequent finish boring process after the semi-finish boring process is 0.2 mm; for finish boring, the cutting speed is 180 r / min and the feed rate is 10 mm / min.

[0035] In this embodiment, the rough boring, semi-finish boring, and finish boring processes all use an emulsion with a mass concentration of 8% to 12% as the cutting fluid. Specifically, the cutting fluid is continuously supplied to the machining area and tool tip through a high-pressure nozzle to achieve lubrication and cooling, reducing tool wear and coating thermal deformation. When the mass concentration of the emulsion is between 8% and 12%, the lubrication and cooling capabilities are optimally balanced. When the mass concentration of the emulsion is less than 8%, the lubricating components are insufficient, the coefficient of friction increases, and the cutting force increases. When the mass concentration of the emulsion is greater than 12%, the proportion of water decreases, and the cooling capacity weakens. In the rough boring process, the cutting fluid can achieve strong cooling and flushing of chips. In the semi-finish boring process, the cutting fluid maintains a constant cutting temperature, avoids dimensional fluctuations, provides stable lubrication, suppresses cutting vibration, ensures a sharp tool tip, and ensures correction accuracy. In the finish boring process, the cutting fluid forms an extremely thin lubricating film between the tool tip and the machined surface, preventing cutting force fluctuations, ensuring stable temperature in the cutting zone, and preventing chip particles from scratching the machined bearing hole inner surface.

[0036] In this embodiment, during step S2, when machining the annular groove, the inner surface roughness of the annular groove is increased by increasing the feed rate and decreasing the cutting speed to achieve a preset value, thereby increasing the bonding strength between the substrate of the bottom hole inner wall and the wear-resistant coating. Specifically, when machining the annular groove, increasing the feed rate increases the surface roughness of the annular groove, thereby increasing the mechanical locking force of the wear-resistant coating embedded in the annular groove substrate and increasing the bonding strength between the substrate of the bottom hole inner wall and the wear-resistant coating; while decreasing the cutting speed helps to ensure the uniformity of roughness, improve the consistency of wear-resistant coating filling, and make the stress distribution of the wear-resistant coating uniform, resulting in higher bonding strength; the two work together to achieve the optimal bonding strength between the substrate of the bottom hole inner wall and the wear-resistant coating.

[0037] In this embodiment, in step S2, the cross-sectional shape of the annular groove is a dovetail groove or a trapezoidal groove. Because dovetail grooves and trapezoidal grooves have a small opening and a large bottom, the coating material, after curing within the annular groove, forms an inverted trapezoidal or inverted dovetail shape that complements the groove shape, creating a mechanically interlocking structure. This significantly improves the bonding strength and helps prevent the wear-resistant coating from peeling off. Optionally, in other embodiments, the cross-sectional shape of the annular groove can also be a rectangular groove or an arc-shaped groove.

[0038] In this embodiment, the annular groove processed in step S2 is a single groove, suitable for bearing installation under conventional loads, with short processing time and low tool cost. Optionally, in other embodiments, multiple annular grooves are processed in step S2, suitable for bearing installation under heavy loads, alternating loads, or with ample axial space. Multiple annular grooves can form multiple wear-resistant coatings, achieving load sharing; when any wear-resistant coating suffers localized damage, other wear-resistant coatings can still provide effective support; multiple wear-resistant coatings collectively absorb impact loads, which helps improve impact resistance; in addition, the increased bonding area between a single wear-resistant coating and the annular groove helps improve bonding strength, prevents the wear-resistant coating from detaching during machining, and eliminates safety hazards during service.

[0039] In summary, after reading the detailed disclosure of this specification, those skilled in the art will understand that the foregoing detailed disclosure is presented by way of example only and is not restrictive. Although not explicitly stated herein, those skilled in the art will understand that this specification requires various reasonable changes, improvements, and modifications to the embodiments. These changes, improvements, and modifications are intended to be made by this specification and are within the spirit and scope of the exemplary embodiments described herein.

[0040] Furthermore, certain terms in this specification have been used to describe embodiments of this specification. For example, "an embodiment," "an embodiment," and / or "some embodiments" mean that a particular feature, structure, or characteristic described in connection with that embodiment may be included in at least one embodiment of this specification. Therefore, it is to be emphasized and understood that two or more references to "an embodiment" or "an embodiment" or "alternative embodiment" in various parts of this specification do not necessarily refer to the same embodiment. Moreover, specific features, structures, or characteristics may be suitably combined in one or more embodiments of this specification.

[0041] It should be understood that in the foregoing description of the embodiments in this specification, various features are combined in a single embodiment, drawing, or description for the purpose of simplifying the description and aiding in the understanding of a feature. However, this does not mean that the combination of these features is necessary, and those skilled in the art may readily identify some of the devices as separate embodiments when reading this specification. That is, the embodiments in this specification can also be understood as an integration of multiple secondary embodiments. It is also valid when each secondary embodiment contains fewer than all the features of a single foregoing disclosed embodiment.

[0042] Finally, it should be understood that the embodiments disclosed in this specification are illustrative of the principles of the embodiments described in this specification. Other modified embodiments are also within the scope of this specification. Therefore, the embodiments disclosed in this specification are merely examples and not limitations. Those skilled in the art can implement the applications in this specification using alternative configurations based on the embodiments in this specification. Therefore, the embodiments in this specification are not limited to the embodiments precisely described in the applications.

Claims

1. A method for machining bearing holes in a light metal intake casing, characterized in that, Includes the following steps: S1: Drill a bottom hole to form the bearing hole at the center of the intake casing axis; S2: At least one annular groove is machined on the inner wall of the bottom hole and corresponding to the bearing mounting position. The annular groove is used to accommodate the sprayed wear-resistant coating so as to support the bearing through the wear-resistant coating. S3: Spray a wear-resistant coating into the annular groove until the annular groove is filled, forming a coating blank that covers the inner surface of the annular groove and at least part of the inner wall of the bottom hole. S4: After the coating is completed, the inner surface of the bearing hole is machined, and excess material of the substrate and coating blank of the bottom hole inner wall is removed to make the diameter accuracy and surface roughness of the bearing hole meet the set requirements, so as to obtain a finished product whose inner surface is composed of the substrate of the bottom hole inner wall and the wear-resistant coating filled in the annular groove.

2. The method for machining the bearing bore of the light metal intake casing according to claim 1, characterized in that, In step S4, the cutting process includes rough boring, semi-finish boring and finish boring in sequence, with the cutting speed and feed rate decreasing sequentially in the rough boring, semi-finish boring and finish boring processes.

3. The method for machining the bearing hole of the light metal intake casing according to claim 2, characterized in that: Rough boring process: cutting speed 250r / min-300r / min, feed rate 15mm / min-18mm / min; Semi-finish boring process: cutting speed 200r / min-250r / min, feed rate 12mm / min-15mm / min; Precision boring process: cutting speed 180r / min-200r / min, feed rate 10mm / min-12mm / min.

4. The method for machining the bearing bore of the light metal intake casing according to claim 2, characterized in that, In the precision boring process, the machining amount of the last pass is 0.1mm.

5. The method for machining the bearing bore of a light metal intake casing according to claim 2, characterized in that, After the rough boring process is completed, the cutting allowance reserved for the subsequent semi-finish boring process is 0.4mm-0.6mm; after the semi-finish boring process is completed, the cutting allowance reserved for the subsequent finish boring process is 0.15mm-0.25mm.

6. The method for machining the bearing bore of a light metal intake casing according to claim 2, characterized in that, The rough boring, semi-finish boring, and finish boring processes are all performed using diamond tools.

7. The method for machining the bearing bore of a light metal intake casing according to claim 2, characterized in that, The rough boring, semi-finish boring, and finish boring processes all use an emulsion with a mass concentration of 8% to 12% as the cutting fluid.

8. The method for machining the bearing bore of a light metal intake casing according to any one of claims 1-7, characterized in that, In step S2, when machining the annular groove, the inner surface roughness of the annular groove is made to reach a preset value by increasing the feed rate and reducing the cutting speed, so as to increase the bonding strength between the substrate of the bottom hole inner wall and the wear-resistant coating.

9. The method for machining the bearing bore of a light metal intake casing according to any one of claims 1-7, characterized in that, In step S2, the cross-sectional shape of the annular groove is a dovetail groove or a trapezoidal groove.

10. The method for machining the bearing bore of a light metal intake casing according to any one of claims 1-7, characterized in that, In step S2, one or more annular grooves are processed.

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