An integrated cutter suitable for stepped hole machining

Abstract

The application provides an integrally formed tool suitable for stepped hole machining, comprising a stepped hole machining part and a tool shank part, characterized in that the stepped hole machining part comprises at least a drilling cutting area and a counterbore cutting area, the drilling cutting area comprises a centering cutting position and an opening cutting position connected with the centering cutting position, and the cutting positions of the centering cutting position and the opening cutting position form a preset inner recess angle. The integrally formed tool suitable for stepped hole machining improves the machining efficiency of the stepped hole.

Description

Technical Field

[0001] This invention relates to the field of cutting tools, and more particularly to a one-piece cutting tool suitable for machining stepped holes. Background Technology

[0002] Machining step holes is a challenging task in the drilling field, as the holes are distributed across two layers with a gap in between. If the gap is long, machining with existing tools becomes difficult. In current technology, machining step holes in automotive steering knuckles made of die-cast aluminum (ADC12) is challenging due to the presence of impurities and air bubbles in the material. Furthermore, the machining of step holes requires high levels of coaxiality, surface roughness, and straightness of the hole walls. Therefore, existing techniques typically employ multiple tools in stages or use highly integrated composite tools for machining.

[0003] In the process of developing the existing technology, the inventors discovered that:

[0004] Using multiple tools for step-by-step machining has problems such as slow machining cycle, long tool overhang during machining, low rigidity, and low precision of machined parts, which affect the machining efficiency. Using highly composite integrated tools to machine parts also has problems such as long tool overhang, low rigidity, and unstable centering during repeated machining, which affect the machining efficiency.

[0005] Therefore, there is a need to provide a high-efficiency tool for machining stepped holes that meet the accuracy requirements of parts, in order to solve the technical problem of low machining efficiency of existing tools for machining stepped holes that meet the accuracy requirements of parts. Summary of the Invention

[0006] The main technical problem solved by this invention is the low machining efficiency of existing cutting tools in machining stepped holes that meet the accuracy requirements of parts. This application provides an integrally formed cutting tool suitable for machining stepped holes, comprising:

[0007] The tool includes a step hole machining section and a tool holder section, characterized in that: the step hole machining section includes at least a drilling cutting area and a reaming cutting area, the drilling cutting area includes a centering cutting position and an opening cutting position connected to the centering cutting position, and the cutting points of the centering cutting position and the opening cutting position form a preset concave angle.

[0008] Furthermore, the angle of the preset concave angle is set to between 130° and 150°.

[0009] Furthermore, the centering cutting position includes at least a cutting drill tip, and the hole-opening cutting position includes at least a plurality of hole-opening cutting edges symmetrically arranged along the axis of the integrally formed tool. A hole-opening chip removal groove is provided between the plurality of hole-opening cutting edges, wherein an irregular chip removal groove is also provided between the cutting drill tip and the hole-opening chip removal groove.

[0010] Furthermore, at least two of the plurality of perforated cutting edges symmetrically arranged along the axis of the integrally formed tool are provided with chip-breaking grooves, and the chip-breaking grooves on the two cutting edges are asymmetrical about the axis of the integrally formed tool.

[0011] Furthermore, the hole-expanding cutting area is provided with a plurality of hole-expanding cutting edges, and a plurality of hole-expanding chip removal grooves are provided between the plurality of hole-expanding cutting edges.

[0012] Furthermore, a first necking section is provided between the drilling cutting area and the reaming cutting area, and the opening chip removal groove of the opening cutting position of the drilling cutting area extends to the first necking section and connects with a portion of the chip removal grooves in the plurality of reaming chip removal grooves.

[0013] Furthermore, the portion where the first necked section meets the drilling cutting area is provided with a chamfer A. The cutting diameter of the first necked section is D1, and the cutting diameter of the drilling cutting area is D2. The cutting diameter D1 of the first necked section and the cutting diameter D2 of the opening cutting position of the drilling cutting area should satisfy D2-D1=2(A+0.25).

[0014] Furthermore, a second necking section is provided between the hole enlargement cutting area of ​​the stepped hole machining part and the tool holder part, and the hole enlargement chip removal groove of the hole enlargement cutting area extends to the second necking section and connects with the tool holder part.

[0015] Furthermore, the portion where the second necked section meets the reaming cutting area is provided with a chamfer B. The cutting diameter of the second necked section is D3, and the cutting diameter of the reaming cutting area is D4. The cutting diameter D3 of the second necked section and the cutting diameter D4 of the reaming cutting area should satisfy D4-D3=2(B+0.25).

[0016] Furthermore, a double internal cooling channel is provided in the step hole machining part and the tool holder part along the axial direction of the integrally formed tool. The double internal cooling channel extends from the tool holder part to the opening cutting end face of the step hole machining part. The double internal cooling channel has a staggered side cooling hole on some of the hole expansion chip removal grooves in the hole expansion cutting area.

[0017] The embodiments provided in this application have at least the following beneficial effects: The one-piece forming tool provided in this application, suitable for machining stepped holes, solves the problems of insufficient rigidity and unstable centering during machining, exhibiting a high self-centering effect and enabling efficient machining of parts meeting the precision requirements of stepped holes. Simultaneously, the tool provided in this application has a low cutting load, making the workpiece less prone to deformation and effectively improving chip width and chip removal performance. Furthermore, the tool provided in this application can control its runout and roundness within 0.005mm to ensure high-precision machining of stepped holes. Attached Figure Description

[0018] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0019] Figure 1 A schematic diagram of an integrally formed tool structure suitable for machining stepped holes, provided in this application;

[0020] Figure 2 Another structural schematic diagram of the integrally formed cutting tool for machining stepped holes provided in this application;

[0021] Figure 3 Another structural schematic diagram of an integrally formed cutting tool suitable for machining stepped holes provided in this application;

[0022] Figure 4 According to Figure 3 A schematic diagram of the cross-sectional structure of A_A of a one-piece forming tool suitable for machining stepped holes;

[0023] Figure 5 A schematic diagram of the processed step hole structure provided in this application.

[0024] Figure Labels

[0025] One-piece tool - 100; Step hole machining section - 1; Drilling cutting zone - 10; Centering cutting position - 101; Cutting drill tip - 1010; Hole opening cutting position - 102; Hole opening cutting edge - 1020; Chip divider - 10201; Hole opening chip removal groove - 1021; Irregular chip removal groove - 1022; Hole reaming cutting zone - 11; Hole reaming cutting edge - 110; Hole reaming chip removal groove - 111; First necking section - 12; Second necking section - 13; Tool holder section - 2; Double internal cooling channel - 30; Offset side cooling hole - 40; Machined step hole workpiece - 200. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. 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.

[0027] Please refer to Figures 1 to 4This application provides an integrally formed cutting tool 100 suitable for machining stepped holes, comprising a stepped hole machining section 1 and a tool holder section 2. The stepped hole machining section 1 includes at least a drilling cutting area 10 and a reaming cutting area 11. The drilling cutting area 10 includes a centering cutting position 101 and an opening cutting position 102 connected to the centering cutting position 101. The cutting points of the centering cutting position 101 and the opening cutting position 102 form a preset concave angle.

[0028] Specifically, the integrated forming tool 100 provided in this application is mainly used for machining step hole structures with connecting functions in automotive steering knuckles, to ensure that the step holes have high coaxiality, surface roughness, and straightness requirements of the hole walls. The integrated forming tool 100 provided in this application includes a step hole machining section 1 and a tool holder section 2. The step hole machining section 1 is mainly used for machining step holes, and the tool holder section 2 is mainly used for clamping the tool holder section 2. It is understood that the lengths of the step hole machining section 1 and the tool holder section 2 should be sufficient to machine the holes at both ends of the step hole. The step hole machining section 1 includes a drilling cutting zone 10 and a reaming cutting zone 11. The drilling cutting zone 10 is mainly used for opening the step hole, and the reaming cutting zone 11 is mainly used for finishing the opened hole. The drilling cutting zone 10 includes a centering cutting position 101 and a hole-opening cutting position 102. The centering cutting position 101 is mainly used to determine the opening position of the step hole, and the hole-opening cutting position 102 is mainly used to process the determined opening position. The cutting points of the centering cutting position 101 and the hole-opening cutting position 102 form a preset concave angle. It can be understood that, for those skilled in the art, the centering cutting position 101 is conical. Since the centering cutting position 101 and the hole-opening cutting position 102 form a preset concave angle, when the hole-opening cutting position 102 connected to the centering cutting position 101 is concave in the opposite direction of the conical direction, the preset concave angle between the centering cutting position 101 and the hole-opening cutting position 102 is satisfied.

[0029] Furthermore, the angle of the preset concave angle is set to between 130° and 150°.

[0030] Specifically, the preset concave angle is related to the centering cutting position 101 and the opening cutting position 102. Setting the preset concave angle between 130° and 150° can ensure that the tool has a good centering effect during machining. For example, if the conical generatrix of the centering cutting position 101 is set to have an angle of 60° with the axial direction of the tool, and the conical generatrix of the opening cutting position 102, which is concave in the opposite direction of the conical orientation, has an angle of 80° with the radial direction of the tool, then the preset concave angle is 140°. In a preferred embodiment provided in this application, the preset concave angle is preferably 140°.

[0031] Furthermore, the centering cutting position 101 includes at least a cutting drill tip 1010, and the hole-opening cutting position 102 includes at least a plurality of hole-opening cutting edges 1020 symmetrically arranged along the axis of the integrally formed tool 100. A hole-opening chip removal groove 1022 is provided between the plurality of hole-opening cutting edges 1020, wherein an irregular chip groove 1022 is also provided between the cutting drill tip 1010 and the hole-opening chip removal groove 1022.

[0032] Specifically, the centering cutting position 101 may include a cutting drill tip 1010 and a chip removal groove for discharging chips drilled by the cutting drill tip 1010. The drilling cutting edge 1020 may include the drilling cutting edge 1020 and a chip removal groove disposed between the drilling cutting edge 1020. It can be understood that in order to ensure smooth removal of cutting chips, an irregular chip groove 1022 is also provided between the cutting drill tip 1010 and the drilling chip removal groove 1022.

[0033] It should be noted that the plurality of hole-opening cutting edges 1020 provided in this application can be double-edged or multi-edged. In a preferred embodiment provided in this application, double-edged edges are preferably arranged symmetrically along the axis of the integrally formed tool 100. This is mainly because the hole-opening cutting edges 1020 are used to remove large amounts of material. Since the overhang of the step hole is relatively long and the depth of the corresponding hole is not deep, it is preferred to be double-edged, which can both ensure normal chip removal and increase the rigidity of the tool.

[0034] Furthermore, at least two of the plurality of perforated cutting edges 1020 symmetrically arranged along the axis of the integrally formed tool 100 are provided with chip-breaking grooves 10201, and the chip-breaking grooves 10201 provided on the two cutting edges are asymmetrical about the axis of the integrally formed tool 100.

[0035] Specifically, chip-breaking grooves 10201, asymmetrically arranged along the axis of the integrally formed tool 100, are formed on several symmetrically arranged cutting edges 1020. This is mainly to prevent misalignment deformation caused by excessive axial shear force when machining stepped holes. The chip-breaking grooves 10201 reduce the width of the cut chips, thereby offsetting some of the axial resistance and resulting in a lower cutting load. The asymmetrical chip-breaking grooves 10201 along the axis of the integrally formed tool 100 are mainly due to the fact that if symmetrical chip-breaking grooves 10201 were used, the machining positions might overlap, leading to missed cuts and tool collisions.

[0036] Furthermore, the hole-expanding cutting area 11 is also provided with a plurality of hole-expanding cutting edges 110, and a plurality of hole-expanding chip removal grooves 111 are provided between the plurality of hole-expanding cutting edges 110.

[0037] Specifically, the reaming cutting edges 110 on the reaming cutting zone 11 are mainly used for semi-finishing or finishing. To ensure sufficient rigidity even with a long tool overhang, this application increases the core thickness of the reaming cutting zone 11 and sets the number of cutting edges in the reaming cutting zone 11 to 4 to 6, preferably 4. That is, the reaming cutting zone 11 has 4 cutting edges distributed circumferentially, and correspondingly, 4 chip removal grooves are provided between the 4 cutting edges.

[0038] Furthermore, a first necking section 12 is provided between the drilling cutting area 10 and the reaming cutting area 11. The opening chip removal groove 1022 of the opening cutting position 102 of the drilling cutting area 10 extends to the first necking section 12 and connects with a portion of the chip removal grooves in the plurality of reaming chip removal grooves 111.

[0039] Specifically, the first necking section 12 is mainly designed to reserve a radial safety distance during the reverse chamfering of the subsequent stepped holes, preventing tool breakage due to interference during machining. The opening chip removal groove 1022 of the opening cutting position 102 in the drilling cutting area 10 extends to the first necking section 12 and connects with a portion of the chip removal grooves in the plurality of enlarged hole chip removal grooves 111, which can be understood as ensuring smooth chip removal. In a preferred embodiment provided in this application, the hole-opening cutting edge 1020 is symmetrically configured as a double-edged blade along the axis of the integrally formed tool 100. Correspondingly, a hole-opening chip removal groove 1022 is provided between the double-edged blades. The hole-expanding cutting edge 110 of the hole-expanding cutting area 11 is symmetrically configured as a four-edged blade along the axis of the integrally formed tool 100. Correspondingly, four hole-expanding chip removal grooves 111 are provided between the four-edged blades along the axis of the integrally formed tool 100. That is, the two hole-expanding chip removal grooves 111 symmetrically configured along the axis of the integrally formed tool 100 in the hole-expanding cutting area 11 are connected to the hole-expanding chip removal grooves 1022 provided between the double-edged blades of the hole-opening cutting edge 1020.

[0040] Furthermore, the portion where the first necked section 12 meets the drilling cutting area 10 is provided with a chamfer A. The cutting diameter of the first necked section 12 is D1, and the cutting diameter of the drilling cutting area 10 is D2. The cutting diameter D1 of the first necked section 12 and the cutting diameter D2 of the opening cutting position 102 of the drilling cutting area 10 should satisfy D2-D1=2(A+0.25).

[0041] Specifically, in a preferred embodiment provided in this application, to ensure that the machining tool does not break during the reverse chamfering of the subsequent stepped hole, a specific functional relationship is defined between the cutting diameter of the first necked section 12 and the cutting diameter at the drilling cutting area 10, namely, D2-D1=2(A+0.25). It can be understood that a chamfer A is provided at the junction of the first necked section 12 and the drilling cutting area 10, that is, chamfer A is provided at all locations of the drilling cutting area 10 except for the chip removal groove. Specifically, the specific value of chamfer A can be matched to the part dimensions.

[0042] It should also be noted that the first necking section 12 and the reaming cutting area 11 are also provided with a chamfer C, the specific value of which can be matched with the part size. It should be understood that the cutting diameter of the reaming cutting area 11 is larger than the cutting diameter of the first necking section 12.

[0043] Furthermore, a second necking section 13 is provided between the hole enlargement cutting area 11 of the stepped hole processing section 1 and the tool holder 2, and the hole enlargement chip removal groove 111 of the hole enlargement cutting area 11 extends to the second necking section 13 and connects with the tool holder 2.

[0044] Specifically, the second necking section 13 is set mainly to reserve a radial safety distance during the reverse chamfering of the subsequent step hole to prevent tool breakage caused by interference during processing.

[0045] Furthermore, the portion where the second necked section 13 meets the reaming cutting area 11 is provided with a chamfer B. The cutting diameter of the second necked section 13 is D3, and the cutting diameter of the reaming cutting area 11 is D4. The cutting diameter D3 of the second necked section 13 and the cutting diameter D4 of the reaming cutting area 11 should satisfy D4-D3=2(B+0.25).

[0046] Specifically, in a preferred embodiment provided in this application, to ensure that the machining tool does not break during the subsequent reverse chamfering of the stepped hole, a specific functional relationship is defined between the cutting diameter of the second necked section 13 and the cutting diameter of the reaming cutting area 11, namely D4-D3=2(B+0.25). It can be understood that the portion where the second necked section 13 connects to the reaming cutting area 11 is provided with a chamfer B, that is, the reaming cutting area 11, except for the chip removal groove, is provided with a chamfer A. Specifically, the specific value of the chamfer A can be matched to the part dimensions.

[0047] It should also be noted that the second necked section 13 and the tool holder 2 are provided with a chamfer D, the specific value of which can be matched with the part size. It should be understood that the cutting diameter of the tool holder 2 is larger than the cutting diameter of the second necked section 13.

[0048] In a preferred embodiment provided in this application, the cutting diameter of the handle portion 2 is set to D5, and the cutting diameter of the handle portion 2 should also satisfy D5=D4+2B, that is, the cutting diameter of the handle portion 2 is mainly to meet the clamping and economy of the handle.

[0049] Furthermore, a double internal cooling channel 30 is provided in the step hole machining section 1 and the tool holder section 2 along the axial direction of the integrally formed tool 100. The double internal cooling channel 30 extends from the tool holder section 2 to the end face of the opening cutting position 102 of the step hole machining section 1. The double internal cooling channel 30 is provided with staggered side cooling holes 40 on some of the hole expansion chip removal grooves 111 in the hole expansion cutting area 11.

[0050] Specifically, a double internal cooling channel 30 is provided in the axial direction of the integral forming tool 100, an internal cooling hole is provided on the end face of the opening cutting position 102 of the step hole machining part 1, and a staggered side cooling hole 40 is provided on part of the reaming chip removal groove 111 of the reaming cutting area 11. All of these are to ensure the cooling and chip removal effect of the drilling cutting area 10 and the reaming cutting area 11 when machining the step hole, and at the same time, to lubricate the hole wall when supporting it, thereby improving the machining quality of the hole wall.

[0051] like Figure 5As shown, this is a machined workpiece 200 with a stepped hole. In a practical application scenario provided in this application, when the tool is machining the workpiece with the stepped hole, the cutting tip 1010 of the centering cutting position 101 first contacts the end face of the workpiece. After drilling and stabilizing the radial oscillation of the tool, when drilling to a preset depth, the outermost tip of the opening cutting position 102 begins to cut the workpiece, forming a three-point positioning, which can minimize radial oscillation. The preset depth is set to 0.3mm to 0.7mm, preferably 0.5mm. When the centering cutting position 101 and the opening cutting position 102 are fully drilled into the end face of the workpiece, the axial resistance of the drilling cutting zone 10 increases. In order to prevent the workpiece from being misaligned and deformed due to excessive axial shear force, a chip groove 10201 is provided on the opening cutting edge 1020 of the opening cutting position 102 to offset part of the resistance. Meanwhile, an irregular chip groove 1022 is also provided between the cutting drill tip 1010 of the centering cutting position 101 and the opening chip removal groove 1022 of the opening cutting position 102 to ensure smooth chip removal. Specifically, the chip removal groove provided in this application changes the traditional straight-line tool pull-out to an arc-shaped pull-out to increase the chip capacity of the chip groove. After one hole of the workpiece to be machined into a stepped hole is completed, the tool extends through the gap layer. At this time, the reaming cutting edge 110 of the reaming cutting zone 11 performs finishing or semi-finishing on the machined hole. During the continued extension of the tool, the tool machine the other hole of the stepped hole to be machined. At the same time, the reaming cutting edge 110 of the reaming cutting zone 11 is still performing finishing or semi-finishing. It can be understood that the reaming cutting edge 110 of the reaming cutting zone 11 provides radial support when machining the other hole of the stepped hole. After the tool finishes machining another hole, the tool continues to extend forward, so that the chamfer C formed by the first necking section 12 and the hole-reaming cutting area 11 and the chamfer C formed by the second necking section 13 and the tool holder 2 perform forward chamfering on the workpiece. After machining, the tool retracts, so that the chamfer A formed at the junction of the first necking section 12 and the drilling cutting area 10 and the chamfer B formed by the second necking section 13 and the hole-reaming cutting area 11 perform reverse chamfering on the workpiece, thereby generating a machined step hole workpiece. It can be understood that the one-piece forming tool 100 for step hole machining provided in this application can ensure the stability of the tool during machining and the low cutting load. At the same time, the core thickness design of the hole-reaming cutting area 11 can improve the rigidity of the tool when the overhang is long.

[0052] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0053] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0054] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. An integrated tool suitable for stepped hole machining, comprising a stepped hole machining portion, a shank portion, characterized in that: The stepped hole processing part at least includes a drilling cutting area and a counterbore cutting area, the drilling cutting area includes a centering cutting position and an opening cutting position connected with the centering cutting position, and the centering cutting position and the opening cutting position have a preset inner recess angle; The centering cutting position at least includes a cutting drill tip, the opening cutting position at least includes a plurality of opening cutting edges arranged symmetrically along the integrated cutter axis, and a plurality of opening chip removal grooves are arranged between the plurality of opening cutting edges, wherein a special chip pocket is arranged between the cutting drill tip and the opening chip removal groove. At least two cutting edges of the plurality of opening cutting edges arranged symmetrically along the integrated cutter axis are provided with chip separation grooves, and the chip separation grooves arranged on the two cutting edges are asymmetric about the axis of the integrated cutter, so as to offset part of the axial resistance. A plurality of counterbore cutting edges are arranged on the counterbore cutting area, and a plurality of counterbore chip removal grooves are arranged between the plurality of counterbore cutting edges. The preset inner recess angle is arranged at an angle of 130° to 150°, so as to form three-point positioning and eliminate radial swing. A first necking section is arranged between the drilling cutting area and the counterbore cutting area, the opening chip removal groove of the opening cutting position of the drilling cutting area extends to the first necking section and connects with part of the plurality of counterbore chip removal grooves. A second necking section is arranged between the counterbore cutting area of the stepped hole processing part and the shank part, and the counterbore chip removal groove of the counterbore cutting area extends to the second necking section and connects with the shank part.

2. The integrally formed cutting tool of claim 1 wherein, A chamfer A is arranged at the joint between the first necking section and the drilling cutting area, the edge diameter of the first necking section is D1, the edge diameter of the drilling cutting area is D2, and the edge diameter D1 of the first necking section and the edge diameter D2 of the opening cutting position of the drilling cutting area should satisfy D2-D1=2(A+0.25).

3. The integrally formed cutting tool of claim 1 wherein, A chamfer B is arranged at the joint between the second necking section and the counterbore cutting area, the edge diameter of the second necking section is D3, the edge diameter of the counterbore cutting area is D4, and the edge diameter D3 of the second necking section and the edge diameter D4 of the counterbore cutting area should satisfy D4-D3=2(B+0.25).

4. The integrally formed cutting tool of claim 1 wherein, A double internal cooling channel is arranged in the axial direction of the integrated cutter and penetrates through the stepped hole processing part and the shank part, the double internal cooling channel extends from the shank part to the opening cutting position end face of the stepped hole processing part, and the double internal cooling channel is provided with a staggered side cooling hole on part of the plurality of counterbore chip removal grooves of the counterbore cutting area.

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