Multi-direction rough milling process of automobile decelerator shell and shell
By employing a multi-directional rough milling process, combined with artificial aging pretreatment, multi-point positioning of surfaces and holes, and dynamic clamping force control, the problems of residual stress, positioning datum, and multi-directional accuracy in the machining of automotive reducer housings were solved, achieving efficient and precise machining results.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- FAW CASTING CO LTD
- Filing Date
- 2026-04-09
- Publication Date
- 2026-06-26
AI Technical Summary
Existing automotive gearbox housing machining suffers from problems such as insufficient residual stress control, defects in the positioning reference system, limited multi-directional machining accuracy, and lack of process monitoring and chip removal, resulting in low machining accuracy and efficiency.
The process employs multi-directional rough milling, including artificial aging pretreatment, a multi-point positioning system for surfaces and holes, dynamic clamping force control, an A-axis rotary table, and online detection and low-temperature stress release, to ensure machining accuracy and efficiency.
It significantly improved the machining accuracy and yield of the housing, reduced clamping errors and vibration mark defects, and improved production efficiency and product quality.
Smart Images
Figure CN122274252A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of automotive technology, and in particular to a multi-directional rough milling process for an automotive reducer housing and the housing itself. Background Technology
[0002] As the core load-bearing component of the transmission system, the machining accuracy of the car reducer housing directly affects the gear meshing stability and the reliability of the vehicle operation. The current mainstream machining process has the following key bottlenecks: (1) Insufficient residual stress control: The housing is mostly made of ductile iron or gray cast iron sand casting, and the casting stress is easy to accumulate inside the blank; the traditional process often omits the pretreatment aging or only uses natural aging, which leads to stress release after rough milling and causes flatness deviation. The subsequent finishing process needs to reserve more allowance, which reduces production efficiency. (2) Defects in the positioning reference system: Conventional processes rely on bolt holes or sealing surfaces as the only reference, which has the problem of reference simplification. It is easy to cause positioning deviation due to casting errors; on the other hand, thin-walled areas are prone to elastic deformation when clamped, especially when the wall thickness is thin, the scrap rate is high. (3) Limited multi-directional machining accuracy: Traditional horizontal milling machines lack high-precision rotary tables. Side milling requires multiple clamping. The accumulated error of reference conversion causes the perpendicularity of adjacent surfaces to exceed the tolerance; and the machining parameters are fixed and cannot be adapted to the cutting requirements of different stiffness areas. Thin-walled areas are prone to vibration marks. (4) Lack of process monitoring and chip removal: During the machining process, key parameters such as clamping force, vibration, and temperature rely on manual experience for judgment. Excessive clamping force will cause the shell to dent, while insufficient clamping force will cause cutting vibration. Milling heat accumulation will cause thermal deformation. Chip accumulation will further aggravate machining errors. (5) Disconnect between stress release and detection: After rough milling, most parts will directly enter the finishing process without targeted low-temperature aging. Incomplete release of cutting stress will cause dimensional drift in subsequent processes. Moreover, detection is mostly offline sampling, which cannot intercept defective parts in real time.
[0003] Based on this, the present invention proposes a multi-directional rough milling process for automotive reducer housings. Summary of the Invention
[0004] The purpose of this invention is to provide a multi-directional rough milling process for automotive reducer housings and a housing itself, establishing a complete process flow from pretreatment, positioning and clamping, multi-directional rough milling, dynamic control to detection and stress release.
[0005] This invention provides the following solution:
[0006] In a first aspect, this application describes a multi-directional rough milling process for an automotive reducer housing, comprising the following steps:
[0007] S1: The shell is artificially aged, and at least two areas are selected on the edge of the preset area of the main positioning reference surface of the shell to open auxiliary positioning holes. The auxiliary positioning reference surface is then ground on the shell. The preset area of the main positioning reference surface and the auxiliary positioning reference surface are located at both ends of the shell.
[0008] S2: Place the housing on the bearing substrate with the auxiliary positioning reference surface and auxiliary positioning hole as the positioning reference, and use the clamping mechanism to clamp the housing at multiple points simultaneously, with the clamping points avoiding the thin-walled area of the housing;
[0009] S3: Using a machining equipment with an A-axis rotary table, the main positioning datum surface is milled in a preset area of the main positioning datum surface with the auxiliary positioning datum surface as the reference, and then the side of the shell is milled with the main positioning datum surface as the reference; the feed rate is dynamically controlled during the milling of the main positioning datum surface and the side of the shell.
[0010] S4: After the flatness of the main positioning reference surface meets the requirements, low-temperature stress relief treatment is carried out.
[0011] Preferably, step S1 specifically includes:
[0012] Select ductile iron or gray cast iron as the shell, and perform artificial aging treatment on the shell to release casting stress;
[0013] At least two non-bolt holes, non-sealing surfaces, and areas far from the final machined functional holes of the housing are selected at the edge of the preset area of the main positioning reference surface of the housing to open auxiliary positioning holes.
[0014] Clean the shell with a neutral degreasing solution;
[0015] Grind the auxiliary positioning reference surface of the housing to ensure that the flatness error of the auxiliary positioning reference surface is ≤0.1mm.
[0016] Preferably, step S2 specifically includes:
[0017] Place the housing on the support base. At this time, the auxiliary positioning reference surface abuts against the support surface of the support base, so that the positioning pin of the clamping mechanism is inserted into the auxiliary positioning hole, and the auxiliary positioning hole is circumferentially limited. The auxiliary positioning reference surface and the auxiliary positioning hole are used as positioning references for multi-point positioning.
[0018] A clamping mechanism is used to clamp the shell at multiple points simultaneously, with the clamping points avoiding the thin-walled areas of the shell.
[0019] Preferably, the clamping mechanism has a built-in force sensor, and the force sensor signal is connected to the CNC system. During the machining process, the clamping force is fed back to the CNC system in real time, and the CNC system dynamically adjusts the clamping force on the housing.
[0020] Preferably, step S3 specifically includes:
[0021] The housing is rough milled in multiple directions using a machining equipment with an A-axis rotary table. The machining sequence is as follows: first, using the auxiliary positioning reference surface as a reference, the main positioning reference surface of the housing is milled in the preset area of the main positioning reference surface. Then, using the main positioning reference surface as a reference, the A-axis table is rotated within the range of 0-90° to mill the side of the housing according to the machining requirements of the side of the housing. During the milling of the main positioning reference surface and the side of the housing, the feed rate is dynamically controlled.
[0022] Preferably, the dynamic control of the feed rate specifically includes:
[0023] The clamping mechanism has a built-in vibration sensor, which is connected to the CNC system.
[0024] The coordinate range of the parts with poor rigidity on the housing is pre-entered into the CNC system. When the milling cutter processes to this coordinate range, the CNC system automatically reduces the feed rate by 20%-30% and sets a vibration acceleration monitoring threshold. Processing is paused when the vibration acceleration monitoring threshold is exceeded.
[0025] Preferably, during the milling of the main positioning reference surface and side surface of the housing, temperature monitoring is also performed, specifically as follows:
[0026] A temperature sensor is built into the root of the positioning pin in the clamping mechanism to monitor the processing temperature in real time, and to suspend processing when the temperature exceeds the threshold.
[0027] Preferably, the milling process of the main positioning reference surface and side surface of the housing is carried out in high-pressure air cooling. The air outlet of the high-pressure air cooling system is equipped with an airflow guide shroud, and a chip removal groove is opened below the milling area. High-pressure air cooling is used to remove chips during the milling process.
[0028] Preferably, step S4 specifically includes:
[0029] After milling, the flatness of the main positioning reference surface is checked. If it meets the corresponding requirements, the shell is unloaded from the bearing substrate and subjected to low-temperature stress relief treatment.
[0030] The flatness of the main positioning reference surface is checked again. After it meets the corresponding requirements, the surface of the housing is blown with compressed air.
[0031] Secondly, this application also describes an automotive reducer housing, which is machined by the aforementioned multi-directional rough milling process for automotive reducer housings.
[0032] Compared with the prior art, the present invention has the following advantages:
[0033] (1) Solving the problem of insufficient control of residual stress: The casting is first pretreated by artificial aging, and then the cutting stress is released again by low temperature aging after rough milling, so that the flatness of the final datum surface is effectively controlled, and the accuracy is significantly improved compared with the traditional process; auxiliary holes are opened in the non-functional area to form a multi-point positioning system of surface-hole with the datum surface, and precise circumferential limit is achieved with the locating pin to solve the problem of single datum positioning offset; the brown corundum grinding wheel is combined with ultrasonic cleaning to ensure that the datum surface is free of oil stains and burrs, providing a stable rough datum for subsequent processing.
[0034] (2) Solve the problem of defects in the positioning reference system: Use column force sensors to monitor clamping force in real time, set different thresholds for shells of different materials, and automatically correct when deviating from the threshold to effectively control the deformation of thin-walled areas; Use multiple sets of hydraulic mechanisms to avoid thin-walled areas and clamp synchronously, and cooperate with the A-axis rotary table to realize multi-face processing in one clamping, greatly reducing clamping errors.
[0035] (3) Solving the problem of multi-directional machining accuracy: The CNC system presets the coordinates of the low stiffness area. When machining to this area, the feed rate is automatically adjusted. Vibration is stopped immediately when it exceeds the threshold, which significantly reduces the vibration defect rate. The temperature sensor at the root of the positioning pin monitors the machining temperature and automatically cools down when it exceeds the threshold. High-pressure air cooling combined with the guide shroud enables the immediate discharge of chips and effectively controls the temperature of the milling area.
[0036] (4) Solve the problem of stress release and detection disconnect: the initial inspection is performed by a digital dial indicator after rough milling, and a second inspection is performed after low temperature aging to ensure that the flatness of the reference surface is qualified and significantly improve the pass rate; the low temperature aging adopts a reasonable heating rate and cools with the furnace to avoid temperature difference stress, which greatly shortens the cycle compared with the traditional natural aging and improves the stress release effect. Attached Figure Description
[0037] Figure 1 This is a flowchart of an embodiment of the present invention. Detailed Implementation
[0038] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0039] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the application. The singular forms “a,” “said,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms, and “multiple” generally includes at least two unless the context clearly indicates otherwise.
[0040] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.
[0041] It should be understood that although the terms first, second, third, etc., may be used in the embodiments of this application, these descriptions should not be limited to these terms. These terms are only used to distinguish the descriptions. For example, first may also be referred to as second without departing from the scope of the embodiments of this application, and similarly, second may also be referred to as first.
[0042] Depending on the context, the words “if” or “suppose” as used here can be interpreted as “when” or “in response to determination” or “in response to detection.” Similarly, depending on the context, the phrases “if determination” or “if detection (of the stated condition or event)” can be interpreted as “when determination” or “in response to determination” or “when detection (of the stated condition or event)” or “in response to detection (of the stated condition or event).”
[0043] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.
[0044] It should be noted that any symbols and / or numbers present in the specification that are not marked in the accompanying drawings are not reference numerals.
[0045] This invention provides a multi-directional rough milling process for an automotive reducer housing, comprising the following steps:
[0046] S1. Pretreatment of shell castings:
[0047] 1.1 Select ductile iron or gray cast iron as the shell casting, and pre-treat the casting with artificial aging to release casting stress;
[0048] 1.2 At least two non-bolt hole, non-sealing surface areas that are far from the functional holes that will be machined in the final stage of the housing are selected at the edge of the preset area of the main positioning reference surface of the housing, and auxiliary positioning holes are opened;
[0049] 1.3 Use an ultrasonic cleaner with a 5-8% neutral degreasing agent solution to clean the shell blank and remove surface oil and impurities;
[0050] 1.4 Use a brown corundum grinding wheel to rough grind out the auxiliary positioning reference surface of the shell, remove casting flash and burrs, and ensure that the flatness error of the auxiliary reference surface is ≤0.1mm.
[0051] S2. Housing positioning and clamping:
[0052] 2.1 Place the housing on the support base of the customized special fixture system, and use the auxiliary positioning reference surface after rough grinding in step S1.4 and the auxiliary positioning hole opened in step S1.2 as the positioning reference to achieve multi-point positioning;
[0053] 2.2 The housing is clamped synchronously at multiple points using a hydraulic clamping mechanism in a 3-4 set of customized special fixture systems, with the clamping points avoiding the thin-walled areas of the housing;
[0054] 2.3 A force sensor is built into the hydraulic clamping mechanism. The force sensor signal is connected to the CNC system. The clamping force is fed back in real time during the machining process. The CNC system adaptively adjusts the clamping force. At the same time, the positioning pin limits the auxiliary positioning hole in the circumferential direction.
[0055] S3, Multi-directional Sequential Rough Milling:
[0056] Multi-directional rough milling is performed using a vertical machining center with an A-axis rotary table. The machining sequence is as follows: First, using the auxiliary positioning reference surface after rough grinding in step 1.4 as the rough reference, the main positioning reference surface of the housing is milled. Then, using the main positioning reference surface as the reference, the A-axis table is rotated to the target angle within the range of 0-90° according to the machining requirements of the side of the housing, and the surrounding side is milled.
[0057] Dynamic control in rough milling:
[0058] A vibration sensor is built into the clamping body of the hydraulic clamping mechanism, and the sensor signal is connected to the CNC system. The coordinate range of the weaker part of the housing is pre-entered into the CNC system. When the milling cutter processes to this coordinate range, the CNC system automatically reduces the feed rate by 20%-30% and sets a vibration acceleration monitoring threshold. If the threshold is exceeded, the processing is paused.
[0059] A temperature sensor is built into the root of the positioning pin in the hydraulic clamping mechanism to monitor the workpiece processing temperature in real time. Processing is paused when the temperature exceeds the threshold.
[0060] In addition, a high-pressure air cooling system is installed on the CNC milling machine worktable, with a stainless steel airflow guide cover at the air outlet. At the same time, a chip removal groove is opened below the milling area of the worktable, so that high-pressure air cooling can be used to remove chips during the milling process.
[0061] S4. Online Detection and Stress Relief:
[0062] 4.1 After rough milling, the flatness of the main positioning reference surface is checked using a digital dial indicator;
[0063] 4.2 After passing the inspection, the shell is unloaded and sent to an aging furnace for low-temperature stress relief treatment;
[0064] 4.3 After low-temperature aging, the flatness of the main positioning reference surface is checked a second time. If it passes the test, the oxide scale and dust on the surface are blown away with compressed air.
[0065] This process effectively controls the flatness of the final positioning reference surface and improves machining accuracy through artificial aging pretreatment and low-temperature aging secondary release; it adopts a surface-hole multi-point positioning system to solve the problem of single reference positioning offset; it effectively controls the deformation of thin-walled areas by real-time monitoring and automatic adjustment of clamping force through force sensors; it completes multi-face machining in one clamping, greatly reducing clamping errors; the intelligent dynamic control system reduces the vibration mark defect rate and improves product quality; and the two-stage inspection combined with low-temperature aging treatment ensures the accuracy of the main positioning reference surface and significantly improves the pass rate.
[0066] Example 1
[0067] S1. Pretreatment of shell castings:
[0068] 1.1 QT450-10 ductile iron was selected as the shell casting. The artificial aging treatment parameters were: temperature 200℃, holding time 5 hours.
[0069] 1.2 On the edge of the housing positioning reference surface, select three areas that are not bolt holes, not sealing surfaces, and far away from the functional holes, and open auxiliary positioning holes with a diameter of 10mm and a tolerance grade of H7.
[0070] 1.3 The shell blank was cleaned for 20 minutes at 45°C using an ultrasonic cleaner with a power of 600W and a frequency of 35kHz and a 6% neutral degreasing agent solution.
[0071] 1.4 The auxiliary positioning reference surface of the housing is rough-ground with a 100-mesh brown corundum grinding wheel to ensure that the flatness error is ≤0.1mm.
[0072] S2. Housing positioning and clamping:
[0073] 2.1 Place the housing with the auxiliary positioning reference surface facing down on the carrier base of the customized special fixture system, insert the positioning pin into the auxiliary positioning hole, and the fit clearance between the two is 0.025mm;
[0074] 2.2 Four sets of hydraulic clamping mechanisms are used to clamp the housing at multiple points simultaneously;
[0075] 2.3 A column-type tension and compression sensor (connected in series to the hydraulic cylinder branch of each hydraulic clamping mechanism) is adopted. The clamping force threshold is set to 5.5kN for the QT450-10 material housing. The CNC system automatically corrects when the deviation from the threshold is ±10%.
[0076] S3. Multi-directional sequential rough milling: A vertical machining center with an A-axis rotation accuracy of ±5″ is used. The milling parameters for the main positioning reference surface are: feed rate 90mm / min, spindle speed 1350r / min, and depth of cut 4mm. The milling parameters for the peripheral side are: feed rate 70mm / min, spindle speed 1100r / min, and depth of cut 3mm.
[0077] Among them, the vibration acceleration monitoring threshold is set to 10m / s², and when processing to the area with a wall thickness ≤5mm, the feed rate is automatically reduced by 25%; the temperature sensor has a range of -20-200℃, an accuracy of ±0.5℃, a temperature threshold of 60℃, and restarts processing when the temperature drops below 40℃.
[0078] The high-pressure air-cooling system has an air pressure of 0.7MPa, an air volume of 18m³ / min, an airflow guide shroud with an inclination angle of 40°, and a chip removal groove width of 65mm.
[0079] S4. Online Detection and Stress Relief:
[0080] The flatness of the main positioning reference surface was checked using a digital dial indicator with an accuracy of 0.01 mm.
[0081] Low-temperature stress relief treatment parameters: temperature 135℃, heating rate 65℃ / h, holding time 2.5 hours, cooling with furnace;
[0082] Use 0.4MPa compressed air to blow away the surface oxide scale and dust, and then perform a secondary inspection of the flatness of the main positioning reference surface.
[0083] Comparative Example 1 (without auxiliary positioning holes):
[0084] Compared to Example 1, no auxiliary positioning holes are provided; the positioning reference is only the ground datum surface, and there is no circumferential positioning pin for limiting the movement. Machining results: During milling, the housing exhibited circumferential offset; the maximum flatness error of the main positioning datum surface was 0.16 mm; and the side perpendicularity error exceeded the tolerance.
[0085] Comparative Example 2 (Manual Mechanical Clamping):
[0086] Compared to Example 1, no hydraulic system or force sensor was installed; a manual screw clamping mechanism was used instead. Processing results: During processing, vibration caused the clamping force to decrease, resulting in a slight lifting of the housing. The maximum flatness error of the main positioning reference surface was 0.14 mm, and flash appeared on the housing due to insufficient clamping force.
[0087] Comparative Example 3 (Multiple clamping at a fixed angle):
[0088] Compared to Example 1, using a conventional vertical machining center without an A-axis requires disassembling the housing and re-clamping it when milling the side. Machining results: The total machining time per piece increased, and the accumulated clamping error led to a maximum side perpendicularity error of 0.18 mm. The housing also suffered scratches on the reference surface due to repeated clamping.
[0089] Comparative Example 4 (No Vibration / Temperature Monitoring):
[0090] Compared to Example 1, the fixture has no vibration or temperature sensors, the feed rate remains unchanged when milling areas with weak rigidity, and there is no over-temperature pause mechanism. Machining results: vibration marks appear in the thin-walled areas of the shell, and the shell surface oxidizes and discolors due to excessively high machining temperatures.
[0091] Experimental verification results:
[0092] Experimental subjects: 100 QT450-10 ductile iron reducer housings; the process of Example 1 and Comparative Examples 1-4 were used.
[0093] Table 1 Test Results
[0094]
[0095] As shown in Table 1, Comparative Example 1, lacking auxiliary positioning holes and relying solely on a single datum surface for positioning, experienced circumferential micro-displacement during milling. This resulted in significantly lower accuracy and pass rates for the flatness of its main positioning datum surface and the perpendicularity of its side surfaces compared to Example 1, with a scrap rate as high as 35%. This demonstrates that the multi-point positioning system consisting of the auxiliary positioning datum surface and auxiliary positioning holes of this invention plays a crucial role in ensuring positioning accuracy and suppressing workpiece displacement.
[0096] Verification of the necessity of dynamic control of clamping force:
[0097] Comparative Example 2 uses traditional manual clamping, which cannot compensate for the clamping force attenuation caused by machining vibration in real time. This not only leads to poor flatness and perpendicularity, but also results in a 10% exceedance rate of vibration marks and poor surface roughness due to clamping force fluctuations. In contrast, Example 1 uses a force sensor to monitor and adjust the clamping force in real time, ensuring clamping stability and eliminating such defects at their source.
[0098] Validation of the advantages of single-clamping and multi-directional machining:
[0099] Comparative Example 3, due to the use of a conventional machining center, required secondary clamping when milling the side surface. This resulted in a significant increase in the total rough milling time for a single piece (88 minutes, far exceeding the 45 minutes of Example 1), and due to errors introduced by datum conversion, its side perpendicularity was the worst among all comparative examples (average 0.17 mm), with a scrap rate as high as 45%. This highlights the significant advantages of the present invention in improving efficiency and accuracy by using a machining equipment with an A-axis worktable, enabling multi-face machining to be completed in a single clamping.
[0100] Validation of the effectiveness of intelligent dynamic monitoring:
[0101] Comparative Example 4, during the machining of thin-walled areas, resulted in severe chatter marks due to the lack of vibration monitoring and adaptive speed reduction, with a chatter mark exceedance rate as high as 40%. Furthermore, the inability to monitor cutting heat led to surface roughness deterioration (Ra 7.5 μm). Although its flatness and perpendicularity were slightly better than other comparative examples, the surface quality issues made it difficult to meet subsequent machining requirements. In contrast, Example 1, through vibration and temperature monitoring, completely eliminated chatter marks and thermal damage, ensuring the integrity of the machined surface.
[0102] In summary, this invention significantly improves the rough milling accuracy, efficiency, and yield of automotive reducer housings by integrating a series of operations, including artificial aging pretreatment, face-hole combination positioning, real-time clamping force control, multi-face machining in a single clamping, and dynamic monitoring of the cutting process.
[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A multi-directional rough milling process for an automotive reducer housing, characterized in that, include: S1: The shell is artificially aged, and at least two areas are selected on the edge of the preset area of the main positioning reference surface of the shell to open auxiliary positioning holes, and the auxiliary positioning reference surface is ground out on the shell. The main positioning reference surface preset area and the auxiliary positioning reference surface are located at both ends of the shell, respectively. S2: Place the housing on the bearing substrate with the auxiliary positioning reference surface and auxiliary positioning hole as the positioning reference, and use the clamping mechanism to clamp the housing at multiple points simultaneously, with the clamping points avoiding the thin-walled area of the housing; S3: Using a machining equipment with an A-axis rotary table, the main positioning datum surface is milled in a preset area of the main positioning datum surface with the auxiliary positioning datum surface as the reference, and then the side of the shell is milled with the main positioning datum surface as the reference; the feed rate is dynamically controlled during the milling of the main positioning datum surface and the side of the shell. S4: After the flatness of the main positioning reference surface meets the requirements, low-temperature stress relief treatment is carried out.
2. The multi-directional rough milling process for the automotive reducer housing according to claim 1, characterized in that, Step S1 specifically includes: Select ductile iron or gray cast iron as the shell, and perform artificial aging treatment on the shell to release casting stress; At least two non-bolt holes, non-sealing surfaces, and areas far from the final machined functional holes of the housing are selected at the edge of the preset area of the main positioning reference surface of the housing to open auxiliary positioning holes. Clean the shell with a neutral degreasing solution; Grind the auxiliary positioning reference surface of the housing to ensure that the flatness error of the auxiliary positioning reference surface is ≤0.1mm.
3. The multi-directional rough milling process for the automotive reducer housing according to claim 1, characterized in that, Step S2 specifically includes: Place the housing on the support base. At this time, the auxiliary positioning reference surface abuts against the support surface of the support base, so that the positioning pin of the clamping mechanism is inserted into the auxiliary positioning hole, and the auxiliary positioning hole is circumferentially limited. The auxiliary positioning reference surface and the auxiliary positioning hole are used as positioning references for multi-point positioning. A clamping mechanism is used to clamp the shell at multiple points simultaneously, with the clamping points avoiding the thin-walled areas of the shell.
4. The multi-directional rough milling process for the automotive reducer housing according to claim 3, characterized in that, The clamping mechanism has a built-in force sensor, and the force sensor signal is connected to the CNC system. During the machining process, the clamping force is fed back to the CNC system in real time, and the CNC system dynamically adjusts the clamping force on the housing.
5. The multi-directional rough milling process for the automotive reducer housing according to claim 3, characterized in that, Step S3 specifically includes: The housing is rough milled in multiple directions using a machining equipment with an A-axis rotary table. The machining sequence is as follows: first, using the auxiliary positioning reference surface as a reference, the main positioning reference surface of the housing is milled in the preset area of the main positioning reference surface. Then, using the main positioning reference surface as a reference, the A-axis table is rotated within the range of 0-90° to mill the side of the housing according to the machining requirements of the side of the housing. During the milling of the main positioning reference surface and the side of the housing, the feed rate is dynamically controlled.
6. The multi-directional rough milling process for the automotive reducer housing according to claim 5, characterized in that, The dynamic control of the feed amount specifically includes: The clamping mechanism has a built-in vibration sensor, which is connected to the CNC system. The coordinate range of the parts with poor rigidity on the housing is pre-entered into the CNC system. When the milling cutter processes to this coordinate range, the CNC system automatically reduces the feed rate by 20%-30% and sets a vibration acceleration monitoring threshold. Processing is paused when the vibration acceleration monitoring threshold is exceeded.
7. The multi-directional rough milling process for the automotive reducer housing according to claim 5, characterized in that, During the milling process of the main positioning reference surface and side surface of the housing, temperature monitoring is also performed, specifically as follows: A temperature sensor is built into the root of the positioning pin in the clamping mechanism to monitor the processing temperature in real time, and to suspend processing when the temperature exceeds the threshold.
8. The multi-directional rough milling process for the automotive reducer housing according to claim 5, characterized in that, The milling process of the main positioning reference surface and side surface of the housing is carried out in high-pressure air cooling. The air outlet of the high-pressure air cooling system is equipped with an airflow guide hood, and a chip removal groove is opened below the milling area. High-pressure air cooling assists in chip removal during the milling process.
9. The multi-directional rough milling process for the automotive reducer housing according to claim 1, characterized in that, Step S4 specifically includes: After milling, the flatness of the main positioning reference surface is checked. If it meets the corresponding requirements, the shell is unloaded from the bearing substrate and subjected to low-temperature stress relief treatment. The flatness of the main positioning reference surface is checked again. After it meets the corresponding requirements, the surface of the housing is blown with compressed air.
10. A car reducer housing, characterized in that, The car reducer housing is machined using the multi-directional rough milling process described in any one of claims 1-9.