A cutting process for hub machining

Abstract

A kind of cutting process of hub machining, including machining sequence from blank into each unit machine tool station, clamped cutting process and tool selection, in a sequence double-tool turret vertical lathe machining, left tool turret turning sequence is as follows: one pass outer rim rough turning, inner rim rough turning, outer rim finish turning, inner rim finish turning;Right tool turret turning sequence is as follows: rough turning, finish turning, flange surface and center hole rough turning, finish turning;Two sequences single-tool turret vertical lathe machining includes: two passes outer rim rough turning, finish turning, cap mouth rough turning, finish turning, face turning;Three sequence machining center drilling processing includes: bolt hole processing, bolt hole installation surface chamfering, valve hole processing, notch, the rough turning cutter used is all PCD diamond blade with 0.03mm-0.1mm blunt cutting edge and 3°-8° rake angle, and drill bit is all drill-mill composite cutting edge.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of machining, in particular to a cutting process for hub machining, especially a cutting process for aluminum alloy hub machining. BACKGROUND

[0002] Even if the design drawing of the product is excellent, if there is no corresponding blank material and cutting process to realize it, the perfect design is just an empty castle. At present, in the aluminum alloy hub machining, the machining production efficiency is very limited, and the quality control is not very stable. The problems are as follows:

[0003] 1. The rough turning of the hub machine is processed by using hard alloy blade, the tool wear is fast, the service life is low, and the frequent replacement of the blade undoubtedly is an important problem affecting the efficiency on site, which increases the change point of process control and loses the production efficiency.

[0004] On the other hand, due to the large cutting amount in rough machining, the cutting force of the blade is unstable, and the PCD diamond blade is currently only applied to finishing due to high hardness, poor toughness and easy to collapse.

[0005] 2. In the first turning, the last turning of the left tool tower is the finishing turning of the outer rim. As known, the hub belongs to a thin-walled workpiece, and the rim thickness is the design size when the last finishing turning of the rim is performed, at which time the rigidity of the rim is the weakest. The outer rim often appears to vibrate the tool during machining, resulting in waste products. The nose radius of the finishing turning tool of the outer rim is R3mm, which is larger than the nose radius of the finishing turning tool of the inner rim, which is R1.2mm. When cutting, the contact area R3 between the nose and the workpiece is larger than R1.2, and it is no doubt that the larger the contact area is, the larger the cutting force is, and the greater the probability of tool vibration is.

[0006] 3. In the first turning, the processing sequence of the right tool tower is: flange face, center hole rough turning → back cavity spoke rough turning → back cavity spoke finishing turning → flange face, center hole finishing turning. Most of the machining equipment is double-tool tower vertical lathe, and the left and right tool towers can be turned at the same time. The processing state of the back cavity spoke of the right tool tower is related to the normal cutting of the inner rim rough turning tool of the left tool tower. The existing cutting sequence cannot guarantee that the back cavity spoke of the right tool tower is processed when the inner rim rough turning tool of the left tool tower is turned to the spoke root. If it is not processed, the back of the inner rim rough turning tool will interfere with the surface to be processed of the back cavity spoke. This interference will increase the load value of each servo shaft of the machine tool, and long-term operation in the interference state will cause the precision of the machine tool to decrease and the components to be damaged. The excessive cutting force will cause the workpiece to slightly move on the clamp, resulting in the generation of waste products, and will accelerate the fatigue of the front end of the tool bar, causing the tool blade to be loose and causing the tool to be broken.

[0007] 4, three sequence machining center drilling processing, the existing drill cannot meet the processing technology demand, because the blank into the cutting plane is irregular, the lateral cutting force is acted on the drill when drilling, the drill is deformed to let the knife. Frequent deformation of the tool in drilling can reduce the service life of the drill, while it can also cause the position tolerance of the bolt hole to be out of tolerance, the hole roundness to be poor; the let go of the valve hole drilling can cause the valve hole to be different in diameter and the valve hole chamfer to be offset, and there is a risk of air leakage at the valve mouth mounting position. SUMMARY

[0008] In view of the above-mentioned deficiencies of the existing process technology, the present application provides a cutting process for hub machining, which can stabilize product quality and effectively reduce manufacturing cost.

[0009] According to the present application, a cutting process for hub machining is provided, which comprises first sequence double-tower vertical lathe machining, second sequence single-tower vertical lathe machining, and third sequence machining center drilling machining. In the first sequence double-tower vertical lathe machining, the left tower turning sequence is: one-way outer rim rough turning, inner rim rough turning, outer rim finish turning, and inner rim finish turning; the right tower turning sequence is: back cavity spoke rough turning, back cavity spoke finish turning, flange face and center hole rough turning, and flange face and center hole finish turning. The second sequence single-tower vertical lathe machining comprises: two-way outer rim rough turning, two-way outer rim finish turning, cap mouth rough turning, cap mouth finish turning, and front turning. The third sequence machining center drilling machining comprises: hub mounting bolt hole machining, bolt hole mounting face chamfering, valve hole machining, and valve hole groove. In the lathe machining, the rough turning tool adopts a PCD diamond blade with a front angle of -3° to -8° and a cutting edge of 0.03mm to 0.1mm. The third sequence machining center drill adopts a drill-mill composite cutting edge.

[0010] The cutting process for hub machining according to the present application can make the cutting more smooth and improve the quality: reduce the machine vibration and waste, eliminate the slight movement of the workpiece on the clamp caused by excessive cutting force, and reduce the position tolerance. The production efficiency is improved: the use life of the rough turning blade is greatly improved by using the PCD diamond blade, the time for replacing the blade is reduced, the change points in the process control are reduced, the product quality is stabilized, and the manufacturing cost is effectively reduced. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 The schematic diagram of the machining of each part of the hub is shown;

[0012] Figure 2 The schematic diagram of the interference between the rear surface of the original process inner rim rough turning tool and the back cavity spoke machining surface is shown;

[0013] Figure 3 The schematic diagram of the inner rim rough turning according to the present application is shown.

[0014] Figure 4 The tool for processing each part of the hub is shown in the figure;

[0015] Figure 5 The side view and top view of the PCD diamond blade suitable for rough turning of the outer rim and rough and fine turning of the back cavity spoke are shown in the figure;

[0016] Figure 6 The side view and top view of the PCD diamond blade suitable for rough turning of the inner rim, rough turning of the center hole and rough turning of the hat mouth are shown in the figure;

[0017] Figure 7 The process flow chart of the hub cutting of the present application is shown in the figure.

[0018] The Arabic numerals in the figure represent as follows: 1. first-order outer rim, 2. inner rim, 3. back cavity spoke, 4. flange face, 5. center hole, 6. second-order outer rim, 7. hub front face, 8. hat mouth, 9. bolt hole, 10. valve hole, 11. first-order and second-order outer rim boundary point, 12. inner rim and back cavity spoke boundary point, 13. inner rim rough turning tool interference position, 14. outer rim R4 rough turning tool, 15. outer rim R3 fine turning tool, 16. inner rim rough turning R3 diamond tool (same model as the center hole rough turning tool and hat mouth rough turning tool), 17. inner rim fine turning R1.2 boat-shaped tool, 18. center hole fine turning R0.8 diamond tool, 19. back cavity spoke R4 rough and fine turning tool, 20. bolt hole drill, 21. bolt hole chamfering tool, 22. valve hole drill, 23. valve hole groove tool. DETAILED DESCRIPTION

[0019] Exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The exemplary embodiments described below and illustrated in the drawings are intended to teach the principles of the invention, enabling those skilled in the art to implement and use the invention in various environments and for various applications. Therefore, the scope of protection of the present invention is defined by the appended claims, and the exemplary embodiments are not intended, and should not be considered, a limiting description of the scope of protection of the present invention. Furthermore, for ease of description, the dimensions of the various parts shown in the drawings are not necessarily drawn to actual scale. Orientation descriptions, such as the longitudinal direction corresponding to the length of the main body, and the orientations or positional relationships indicated by up, down, left, right, top, bottom, etc., are based on the orientations or positional relationships shown in the drawings and are only for the purpose of facilitating the description of the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Unless otherwise specifically stated, the order and numerical values ​​of the components and assembly steps described in the embodiments do not limit the scope of the present invention. Moreover, any numerical range stated herein is intended to include all sub-ranges contained therein, and a numerical range expressed as "numerical value A to numerical value B" refers to a range including endpoints numerical values ​​A and B. Those skilled in the art will understand that the terms "first," "second," and "step" in this invention are used only to distinguish different steps, devices, or modules, and do not represent any specific technical meaning, nor do they indicate a necessary logical order between them. For example, steps two and three can be interchanged or performed in parallel. The invention will be further described in detail below with reference to embodiments and accompanying drawings.

[0020] like Figure 2 As shown, when machining using the original cutting process, the surface to be machined on the back cavity spokes interferes with the roughing tool body of the inner rim, forming the interference part 13 of the roughing tool for the inner rim.

[0021] The cutting process for wheel hub machining according to the present invention includes the machining process after the blank enters the workstation of each unit machine tool for clamping, as well as the selection of cutting tools.

[0022] like Figure 3 As shown in the following description, after changing the machining sequence, when the roughing tool of the inner rim of the left turret is turning the root of the spoke, the machining of the spoke of the back cavity of the right turret has been completed. This fundamentally eliminates the interference between the tool body of the roughing tool of the inner rim of the left turret and the machined surface of the spoke of the back cavity, reduces the machine tool load, and makes cutting smoother.

[0023] like Figure 4As shown, all inserts used in lathe machining are PCD diamond inserts. These inserts have a carbide base with a PCD composite sheet welded to the cutting edge. The carbide base provides the PCD composite sheet with mechanical rigidity, increasing its bending strength. Machining center tools use tool steel for the tool body, which is inlaid with carbide sheets at the cutting edge. This design simplifies tool manufacturing and reduces costs.

[0024] like Figure 5 The roughing PCD diamond insert shown has a -5° rake angle and a 0.03mm blunting of the cutting edge, ensuring both the rigidity of the roughing tool and improving the impact resistance of the cutting edge. This insert can be mounted on the 14 tool holder of an outer rim R4 roughing tool and the 19 tool holder of a back-cavity wheel spoke R4 roughing and finishing tool. In other words, in vertical turning, the R4 diamond insert replaces the existing roughing carbide inserts for roughing outer rims and turning back-cavity wheel spokes.

[0025] like Figure 6 The PCD diamond insert shown features a -5° rake angle and a 0.03mm blunting of the cutting edge, ensuring both the rigidity of the roughing tool and improving the impact resistance of the cutting edge. This insert can be installed on R3 diamond-shaped inserts 16 for roughing inner rims and center holes. Specifically, R3 diamond inserts are used for roughing inner rims, flange faces, center holes, and caps, replacing existing carbide roughing inserts.

[0026] like Figure 7 As shown, the cutting process for wheel hub machining according to the present invention includes: a first-stage double-turret vertical turning, a second-stage single-turret vertical turning, and a third-stage machining center drilling.

[0027] In a single-stage double-turret vertical lathe machining process, the turning sequence of the left turret is as follows: rough turning of the outer rim of the blank (i.e., one rough turning of the outer rim) → rough turning of the inner rim → finish turning of the outer rim (i.e., one finish turning of the outer rim) → finish turning of the inner rim.

[0028] As mentioned earlier (see Background Technology Section 2), the original process of finishing the outer rim was scheduled for the last machining step. As is well known, the wheel hub is a thin-walled workpiece. When finishing the rim, the wall thickness of the rim is the design dimension. At this time, the rigidity of the rim is the weakest. During the machining, the outer rim often produces defective products due to vibration. The tool tip radius of the finishing tool for the outer rim is R3mm, which is larger than the tool tip radius of the finishing tool for the inner rim (1.2mm). During cutting, the contact area between the tool tip and the workpiece is larger than R1.2. Undoubtedly, the larger the contact area, the greater the cutting force, and the greater the probability of vibration.

[0029] According to the present invention, by performing the finishing turning of the outer rim before the finishing turning of the inner rim, the vibration generated during the finishing turning of the outer rim can be eliminated.

[0030] In the first sequence double-turret vertical lathe machining, the right-turret turning sequence is: rough turning of back cavity spoke, fine turning of back cavity spoke, rough turning of flange face and center hole, and fine turning of flange face and center hole.

[0031] As mentioned above (see section 3 of the background), the original process first rough turns the flange face and the center hole, which cannot guarantee the machining state of the back cavity spoke when the left-turret inner rim rough turning tool machines the spoke root.

[0032] According to the present application, by rough turning the flange face and the center hole after rough turning and fine turning of the back cavity spoke, the machining state of the back cavity spoke can be guaranteed when the left-turret inner rim rough turning tool turns the spoke root, and the interference caused by the unprocessed surface of the back cavity spoke to the inner rim rough turning tool body will not occur. The excessive cutting force that causes the workpiece to slightly move on the clamp, resulting in balanced waste and tool breaking waste, is eliminated.

[0033] The above preferred example of the PCD diamond tool bit with a rake angle of -5° and a cutting edge of 0.03 mm is passivated, but is not limited thereto, and the rake angle can be selected in the range of -3° to -8°, and the cutting edge passivation can be selected in the range of 0.03 mm to 0.1 mm. Here, the cutting edge passivation refers to: rounding the edge to prevent chipping during rough turning, improve the impact resistance of the cutting edge, and achieve the purpose of being strong and durable.

[0034] The second sequence single-turret vertical lathe machining includes: two-way outer rim rough turning, two-way outer rim fine turning, cap mouth rough turning, cap mouth fine turning, and front face turning.

[0035] The three-sequence machining center drilling machining includes: hub mounting bolt hole machining, bolt hole mounting face chamfering, air valve hole machining, and air valve hole marking.

[0036] In the three-sequence machining center drilling machining, all the tools used are designed with drill-mill composite cutting edges, which effectively improves the tool retraction when drilling the irregular cutting surface of the casting blank entry point. Specifically, the cutting edges of the machining center bolt hole drill 20 and the air valve hole drill 22 are designed with drill-mill composite tool structure, which improves the cutting performance of the drill, greatly reduces the lateral force in cutting, and effectively avoids tool retraction. In this way, the machining is more stable, which is beneficial to the quality control of the machined hole and improves the service life of the drill, effectively saving the manufacturing cost.

[0037] Thus, according to the cutting process for hub machining of the present application, the rough turning tool adopts PCD diamond inserts to replace the original two carbide inserts, and the two PCD diamond inserts are designed with a front angle of-5° and a cutting edge of 0.03mm bluntness. Among them, by adopting PCD diamond inserts to replace the original two carbide inserts, the outer rim rough turning and the back cavity spoke rough and finish turning are the same PCD diamond insert with a R4 tool tip radius, which well guarantees the strength of the tool; the inner rim rough turning, flange face, center hole rough turning and cap rough turning adopt the same rhombus R3 insert. The front angle of the two PCD diamond inserts for rough turning is-5°, which increases the insert wedge angle and effectively improves the rigidity of the insert, and the insert edge is 0.03mm bluntness, which retains the sharpness of the cutting edge while improving the impact resistance of the cutting edge.

[0038] In addition, by reasonably setting the hub machining sequence, the left tool tower inner rim finish turning R1.2 turning tool is placed at the end of turning, which effectively reduces the cutting force of the rim weak point and avoids the generation of outer rim vibration tool waste. The back cavity spoke processing is set at the beginning of the right tool tower program, which ensures that the left tool tower inner rim rough turning tool does not interfere with the back cavity spoke to be processed when machining the spoke root.

[0039] In addition, the drill bit of the three-sequence machining center adopts a drill-mill composite cutting edge design, which greatly reduces the lateral force in drilling, effectively avoids the tool deflection, makes the machining more stable, is beneficial to the quality control of the machined hole, and improves the service life of the drill bit, effectively saving the manufacturing cost.

[0040] Although the present application has been described with reference to various specific embodiments, it will be understood that modifications can be made within the spirit and scope of the inventive concepts described. Accordingly, it is intended that the present application not be limited to the described embodiments, but will have the full scope defined by the language of the following claims.

Claims

1. A cutting process for hub machining, characterized by, The application relates to a lathe machining method, which comprises one-order double-tool-tower vertical lathe machining, two-order single-tool-tower vertical lathe machining and three-order machining center drilling machining. In the one-order double-tool-tower vertical lathe machining, the left-tool-tower turning sequence is as follows: one-way outer rim rough turning, inner rim rough turning, outer rim fine turning and inner rim fine turning; the right-tool-tower turning sequence is as follows: back cavity spoke rough turning, back cavity spoke fine turning, flange face and center hole rough turning and flange face and center hole fine turning; the two-order single-tool-tower vertical lathe machining comprises the following steps: two-way outer rim rough turning, two-way outer rim fine turning, cap mouth rough turning, cap mouth fine turning and front face turning; the three-order machining center drilling machining comprises the following steps: wheel hub installation bolt hole machining, bolt hole installation face chamfering, air valve hole machining and air valve hole marking, wherein the rough turning tools used in the lathe machining are PCD diamond blades with a front angle of -3 to -8 DEG and a cutting edge of 0.03 to 0.1 mm, the three-order machining center drills are all provided with drilling and milling composite cutting edges, the back cavity spoke turning sequence composed of back cavity spoke rough turning and back cavity spoke fine turning is arranged before the inner rim rough turning of the left-tool-tower, the rough turning tools used in the lathe machining are all PCD diamond blades with a front angle of -5 DEG and a cutting edge of 0.03 mm, the PCD diamond blade is made of a hard alloy material, and a PCD composite piece is welded on a cutting edge, the PCD diamond blade for one-way outer rim rough turning, back cavity spoke rough turning and back cavity spoke fine turning is the same PCD diamond blade with a tool tip radius, the PCD diamond blades for inner rim rough turning, flange face and center hole rough turning and cap mouth rough turning are all diamond-shaped blades, in the one-order double-tool-tower vertical lathe machining, the tool tip radius of the outer rim fine turning tool of the left-tool-tower is 3 mm, and the tool tip radius of the inner rim fine turning tool is 1.2 mm.

2. The hub-machined cutting process of claim 1, wherein, the PCD diamond blade for one-way outer rim rough turning, back cavity spoke rough turning and back cavity spoke fine turning is the same PCD diamond blade with a tool tip radius of R4.

3. The hub-machined cutting process of claim 1, wherein, the PCD diamond blades for inner rim rough turning, flange face and center hole rough turning and cap mouth rough turning are all diamond-shaped blades with the same tool tip radius of R3.

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