A combined cutting tool for spot welding electrode automatic grinding device

Abstract

The invention discloses a combined cutting tool for an automatic grinding device for spot welding electrodes, comprising a cutter shaft (1), the shaft end of which is equipped with a spur gear (2); one end of the cutter shaft (1) is provided with a flange (7), the inner surface of the flange (7) is used as a positioning base surface when the spur gear (2) is assembled with the cutter shaft; the other end of the cutter shaft (1) is provided with a threaded hole (18) at the axis center, and the threaded hole (18) is used as a bolt assembly hole when the cutter shaft (1) is axially constrained. The invention improves the flatness of the working surface of the electrode after grinding, and has a beneficial effect on improving the electrode feeding efficiency and ensuring the quality of the welding spot.

Description

Technical Field

[0001] The invention relates to an electrode grinding tool used for grinding a resistance spot welding electrode, in particular to a combined cutting tool placed in a special electrode automatic grinder and used for grinding the working end of a resistance spot welding electrode. Background Art

[0002] The electrode is placed at the end of the electrode grip, commonly known as the electrode cap. During spot welding, the flat parts of the electrode ends on both sides are the working surfaces, which clamp the workpiece to be welded and specifically perform pressure on the welded part and the introduction of welding current to the workpiece to be welded. After the electrode is welded at one point, the state of the working plane of the electrode end changes and needs to be sharpened in time. The automatic electrode sharpener and the cutting tool inside it are one of the methods for sharpening the working end surface of the electrode.

[0003] During the resistance spot welding process, the electrode automatic grinder uses the cutting tool placed therein to achieve the purpose of grinding the working end surface of the electrode. The electrode automatic grinder of the known technology has the following main shortcomings due to the structural design type of the cutting tool and its working principle:

[0004] 1. An integral cutting tool with cutting edges on both sides is used to synchronously grind the end faces of the electrodes to be repaired on both sides, and the cutting edges on both sides are in a mirror image relationship; limited by the working principle, a single-edge structure is basically used.

[0005] 2. During the electrode grinding process, the electrode pressure always acts vertically on the cutting edges of the cutting tools on both sides. The essence of the electrode grinding method is scraping grinding. The working principle of the cutting tool determines that the cutting force during electrode grinding must be established by the electrode pressure and the rotational torque of the cutting edge. During the electrode grinding process, one side of the cutting edge grinds the end face of the electrode to be repaired by positive scraping, and the other side of the cutting edge grinds the end face of the electrode to be repaired by reverse scraping. The essential characteristic of this scraping grinding determines that the cutting tool cutting edge not only wears very quickly, but also the wear rates of the cutting edges on both sides are very different. Under the same grinding conditions, the difference between the grinding quality of the working ends of the electrodes on both sides and the grinding amount each time will gradually increase with the increase in the number of cutting edge working times.

[0006] 3. Due to the repeatability error of the spot welding robot, the designed working length of the cutting edge for grinding the electrode working plane must be greater than or equal to the sum of the working radius of the electrode to be cut and ground and the repeatability accuracy of the electrode, so as to ensure that the electrode surface to be repaired can be effectively cut and ground within the repeatability accuracy range; from a probability and statistical perspective, about 50% of the cutting and grinding is carried out under the condition that the local cutting edge exceeds the electrode radius, and the local cutting edge exceeding the electrode radius works under the hard extrusion state of the reverse blade, while the cutting edge at the center of each scraping rotation of the cutting tool is ground on the electrode working surface under the conditions of rotating rolling and rotating tearing, which can easily cause rapid wear or chipping of the cutting edge in the above-mentioned area.

[0007] 4. Due to the constraints of the design conditions and cutting edge working conditions described in Item 2, the use of cutting tools with multiple cutting edge structures for the purpose of reducing the cutting edge workload is limited, and the possibility of automatic chip breaking at the cutting edge is also excluded. The so-called chips are actually continuously squeezed stacked chips. The squeezed stacked chips that are not discharged in time may hinder the continuous and stable scraping work of the cutting edge, or easily cause accelerated wear or chipping of the cutting edge.

[0008] 5. The cutting tool is fixedly mounted on the tool holder in the automatic electrode grinder and rotates synchronously with the tool holder; the rotation axis of the cutting tool always remains coaxial with the axis established by the center line connecting the working surfaces of the two electrodes. The working surface of the electrode after grinding is actually a spherical surface with a helix angle corresponding to the radius of curvature of the cutting edge of this section of the cutting tool and determined by the cutting edge cutting depth.

[0009] 6. Since the rotation axis of the cutting edge is coaxial with the electrode axis, during the cutting process, the differences in the rotational linear velocity and rotational linear acceleration between the cutting edge center and the cutting edge outer edge are extremely large, that is, the working load or bending moment borne by each part along the entire length of the cutting edge is very different. The outer edge cutting edge becomes a dangerous part because of the largest rotational acceleration, and the cutting edge that exceeds the rotation axis part also becomes another dangerous part of the cutting edge due to the hard extrusion of the reverse blade; at the same time, due to the great difference in the cutting linear velocity of each part of the entire length of the cutting edge, it is also easy to cause different grinding quality of each part of the electrode end face after grinding.

[0010] Since the cutting tool edge works under the above-mentioned series of extremely unfavorable working conditions, even if relatively expensive materials are selected to make the cutting tool, it is difficult to get rid of the current situation that the cutting tool is a frequently wearing part in the automatic electrode grinder. Summary of the invention

[0011] The invention overcomes the shortcomings of the prior art and provides a combined cutting tool for an automatic grinding device for spot welding electrodes.

[0012] The technical solution adopted by the present invention is:

[0013] 1. By changing the structure of the cutting tool and its cutting working principle, a multi-edge combination cutting tool with a rake angle is introduced into the automatic electrode grinder, and the scraping grinding nature of the electrode in the known technology is changed to cutting grinding.

[0014] 2. The cutting tool cuts and grinds the end of the electrode to be repaired in the form of revolution and rotation without the help of electrode pressure, eliminating the unfavorable scraping and grinding phenomenon in the known technology.

[0015] 3. The unnecessary cutting and grinding amount in the known technology is extremely compressed through the micro-cutting positioning and shifting cutting method, and the cutting load in the smaller grinding amount is shared by the multi-edge edges of the combined cutting tool, further reducing the cutting stress of the cutting tool edge.

[0016] 4. The negative impact of the bending deformation of the welding clamp arm and the distance between the electrodes on both sides during grinding on the contact state between the electrode working surface and the workpiece surface can be corrected and compensated by adjusting the grinding angle. With the joint support of the above technical measures, the average service life of the cutting tool can be increased by more than ten times, and the utilization rate of the electrode material can be increased by more than 50%.

[0017] The specific improvements are as follows:

[0018] A combined cutting tool for an automatic grinding device for spot welding electrodes comprises a cutting shaft (1), wherein the shaft end of the cutting shaft (1) is equipped with a spur gear (2). The innovation of the present invention lies in:

[0019] One end of the cutter shaft (1) is provided with a flange (7), the inner surface of the flange (7) being used as a positioning base surface when the spur gear (2) is assembled therewith; the other end of the cutter shaft (1) is provided with a threaded hole (18) at its axis, the threaded hole (18) being used as a bolt assembly hole when the cutter shaft (1) is axially constrained;

[0020] A first circular depression (6) is formed on the shaft end of the spur gear (2) along the axis, and the bottom surface of the first circular depression (6) serves as a positioning base surface after the cutter shaft (1) is inserted into the shaft hole of the spur gear (2); a second circular depression (8) is formed on the other side of the disk of the spur gear (2), and the first cutting tool (4) is fixedly installed in the second circular depression (8) by using two fixing pins (3), so that the two become a combined component;

[0021] The second cutting tool (5) or (17) is coaxially embedded in a third circular sink (10) centrally symmetrical on the first cutting tool (4); the spur gear (2) and the second cutting tool (5) or (17) are radially constrained and fixed to the cutter shaft (1) by a key (11);

[0022] The first cutting tool (4) is in the shape of a thin-walled circular disk; a plurality of identical cutting edges (9) with radial trajectory lines are evenly distributed relative to the center of the convex annular surface on the outer side of the second circular sink (8); and a plurality of cutting edges with identical geometric dimensions are formed along the axial direction on the axial outer side surface of the second cutting tool (5) or (17);

[0023] The second cutting tool (5) or (17) comprises a curved cutting tool (5) and a truncated cone-shaped cutting tool (17).

[0024] Furthermore, when the first cutting tool (4) rotates to grind the electrode, the rotation plane of its cutting edge always fits the working end plane part (12) of the electrode to be cut and ground, and only performs the grinding work of the working end plane part (12) of the electrode.

[0025] Furthermore, when the arc surface cutting tool (5) is rotating to grind the electrode to be cut and ground, the contour trajectory of the cutting edge rotation is in contact with the arc surface curve (15) on the side of the arc surface electrode (13), and only the side of the working end of the arc surface electrode (13) is ground.

[0026] Furthermore, the contour trajectory line is composed of a concave arc segment and a straight line segment from the small end to the large end of the arc surface cutting tool (5); the radius of the arc segment is the same as the arc radius of the arc surface curve (15) in the electrode to be ground.

[0027] Furthermore, when the truncated cone-shaped cutting tool (17) rotates to grind the electrode to be cut, the contour trajectory of the rotating cutting edge fits the conical surface (16) on the side of the truncated cone-shaped electrode (14), and only grinds the side of the working end of the truncated cone-shaped electrode (14).

[0028] Furthermore, the cone angle of the truncated cone-shaped cutting tool (17) is the same as the cone angle of the cone surface (16) of the working end side surface of the truncated cone-shaped electrode (14) to be ground.

[0029] Furthermore, the first cutting tool (4) comprises a plurality of cutting edges (9) of the same geometric shape, and the relationship between the front angle α, blade thickness f, blade thickness back angle θ, blade back width e, disk diameter D1 and number of cutting edges n1 of the cutting edge (9) and the spot welding material is as follows:

[0030] Spot welding material Rake angle α Blade thickness f Blade thickness back angle θ Width behind blade e Disc diameter D1 Number of cutting edges n1 Steel Plate 3～8° f≥0.2mm 15～25° ≥0.8mm ≥30 ≥32 Aluminum Plate 2.5～5° f≥0.3mm 15～25° ≥0.8mm ≥35 ≥34

[0031] Furthermore, the arc surface cutting tool (5) comprises a plurality of cutting edges of the same geometric shape; the relationship between the cutting edge diameter D5, the cutting edge diameter D3, the number of cutting edges n2 and the cutting edge helix angle ω2 of the arc surface cutting tool (5) and the electrode diameter R of the arc surface electrode (13) to be cut and ground is as follows:

[0032] Electrode diameter R Cutting tool large end diameter D5 Small end diameter of cutting tool D3 Number of cutting edges n2 Helix angle ω 13mm ≥35mm ≥9mm 8 to 14 0～3° 16mm ≥43mm ≥11mm 14 to 20 0～4° 22mm ≥52mm ≥12mm 18 to 25 0～5°

[0033] Furthermore, the truncated cone-shaped cutting tool (17) comprises a plurality of cutting edges of the same geometric shape; the relationship between the cutting edge diameter D5, the cutting edge diameter D3, the number of cutting edges n3 and the cutting edge back rake angle ε of the truncated cone-shaped cutting tool (17) and the electrode diameter R of the truncated cone-shaped electrode (14) to be cut and ground is as follows:

[0034] Electrode diameter R Cutting tool large end diameter D5 Small end diameter of cutting tool D3 Number of cutting edges n3 Caster angle ε 13mm ≥35mm ≥9mm 8 to 14 10～13° 16mm ≥43mm ≥11mm 14 to 18 11～14° 22mm ≥52mm ≥12mm 18 to 23 12～15°

[0035] Furthermore, the structural parameters of the first cutting tool (4), the arc-surface cutting tool (5) and the truncated cone-shaped cutting tool (17) are selected according to the material to be spot welded:

[0036] (1) When the first cutting tool (4), the arc-surface cutting tool (5) and the truncated cone-shaped cutting tool (17) are used for electrode grinding of spot-welded steel plates:

[0037] The geometric parameters of the cutting edge include the front angle α, the back angle δ, the blade thickness f, the back width e and the back angle θ of the blade thickness. The recommended values ​​of the relationship between the front angle α, the back angle δ, the blade thickness f, the back width e and the back angle θ of the blade thickness are as follows:

[0038] Rake angle α Back angle δ Blade thickness f Width behind blade e Blade thickness back angle θ 3～8° 8～12° ≥0.2mm ≥0.8mm 15～25°

[0039] (2) When the first cutting tool (4), the arc-surface cutting tool (5) and the truncated cone-shaped cutting tool (17) are used for grinding electrodes for spot welding of aluminum or aluminum alloy:

[0040] The geometric parameters of the cutting edge include the front angle α, the back angle δ, the blade thickness f, the back width e and the back angle θ of the blade thickness. The recommended values ​​of the relationship between the front angle α, the back angle δ, the blade thickness f, the back width e and the back angle θ of the blade thickness are as follows:

[0041] Rake angle α Back angle δ Blade thickness f Width behind blade e Blade thickness back angle θ 2.5～5° 8～12° ≥0.3mm ≥0.8mm 15～25°

[0042] The technical effects achieved by the present invention are:

[0043] 1. In the present invention, due to the fundamental change in the structure of the cutting tool and its cutting and grinding principle, and the fact that each cutting tool in the combined cutting tool has the characteristics of multiple cutting edges, the total cutting and grinding amount during each electrode grinding is shared by multiple cutting edges, which can increase the service life of the cutting tool by several times.

[0044] 2. The present invention allows the cutting edge to be designed to be sharper, creating the necessary conditions for small-knife-measurement positioning and shifting cutting and grinding of electrodes, further reducing the cutting stress level during the cutting and grinding process of the cutting tool and increasing the service life of the cutting tool. It is easy to achieve positioning and shifting cutting during electrode grinding, which is beneficial to inhibiting excessive cutting of the electrode and reducing electrode consumption.

[0045] 3. The present invention improves the flatness of the working surface of the electrode after grinding, which has a beneficial effect on improving the electrode feeding efficiency and ensuring the quality of the welding point. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1-1 is an axial cross-sectional view of the combination of the first cutting tool and the curved cutting tool in the present invention;

[0047] Figure 1-2 yes Figure 1-1 A top view of

[0048] Figure 2-1 is an axial cross-sectional view of the combination of the first cutting tool and the truncated cone-shaped cutting tool in the present invention;

[0049] Figure 2-2 yes Figure 2-1 A top view of

[0050] Figure 3-1 is an axial cross-sectional view of the first cutting tool of the present invention;

[0051] Figure 3-2 yes Figure 3-1 A top view of

[0052] Figure 4-1 is an axial cross-sectional view of the arc surface cutting tool of the present invention;

[0053] Figure 4-2 yes Figure 4-1 A top view of

[0054] Figure 5-1 is an axial cross-sectional view of the truncated cone-shaped cutting tool of the present invention;

[0055] Figure 5-2 yes Figure 5-1 A top view of

[0056] Figure 6 It is an enlarged view of the cutting edge I of each cutting tool;

[0057] Figure 7-1 It is a structural diagram of the curved electrode;

[0058] Figure 7-2 It is a structural diagram of a truncated cone electrode.

[0059] In the figure: 1-blade shaft, 2-spur gear, 3-fixing pin, 4-first cutting tool, 5-arc cutting tool, 6-first circular sink, 7-flange, 8-second circular sink, 9-cutting edge, 10-third circular sink, 11-key, 12-working end plane part, 13-arc electrode, 14-truncated cone electrode, 15-external convex arc surface + straight line part, 16-conical surface part of working end of electrode, 17-truncated cone cutting tool. DETAILED DESCRIPTION

[0060] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The described specific embodiments are only used to explain the present invention and are not intended to limit the present invention.

[0061] A combined cutting tool for an automatic grinding device for spot welding electrodes comprises a cutter shaft 1, wherein the shaft end of the cutter shaft 1 is equipped with a spur gear 2; the innovation of the present invention lies in that: one end of the cutter shaft 1 is provided with a flange 7, the inner surface of the flange 7 is used as a positioning base surface when the spur gear 2 is assembled with the cutter shaft 1; a threaded hole 18 is formed at the axis of the other end of the cutter shaft 1, and the threaded hole 18 is used as a bolt assembly hole (for axial constraint of the cutter shaft 1).

[0062] like Figure 1-1 , Figure 1-2 , Figure 2-1 and Figure 2-2As shown, the shaft end of the cutter shaft 1 is inserted from one side of the central through hole of the first circular depression 6 at the shaft end of the spur gear 2, and the flange 7 on the cutter shaft 1 is embedded in the first circular depression 6; a second circular depression 8 is also opened on the disk surface on the other side of the spur gear 2, and a first cutting tool 4 is fixedly installed in the circular depression by two fixing pins 3, so that the two become a combination; the appearance of the first cutting tool 4 is a thin-walled disk with a third circular depression 10 opened on one side surface, and a radial cutting edge 9 of the first cutting tool is opened on the raised annular surface on the outer side of the circular depression; a second cutting tool 5 or 17 is coaxially embedded in the circular depression of the first cutting tool, and a key 11 is used to realize radial constraint fixation between the spur gear 2 and the second cutting tool 5 or 17 and the cutter shaft 1.

[0063] like Figure 3-1 and Figure 3-2 As shown, the appearance of the first cutting tool 4 is a thin-walled disc; on one side of the disc, a third circular depression 10 is symmetrically opened, and on the convex annular surface outside the third circular depression 10, a plurality of identical radial cutting edges are evenly distributed relative to the center of the circle; the first cutting tool is equivalent to an annular end milling cutter; when the first cutting tool 4 rotates to grind the electrode, the cutting edge rotation plane 9 is always aligned with the electrode working end plane part 12 (such as the electrode working end to be cut and ground) of the working end of the electrode to be cut. Figure 7-1 and Figure 7-2 ) and only undertakes the grinding of the flat surface part 12 of the working end of the electrode.

[0064] In the present invention, the geometric shape of the cutting edge of the first cutting tool 4 can be described by the parameters of the cutting edge rake angle α, blade thickness f, blade thickness back angle θ and blade width e; wherein, the larger the rake angle α, the sharper the cutting edge, but the load bearing capacity is correspondingly reduced; the blade thickness f, back angle θ and blade width e are common representations of the supporting capacity of the blade back portion of the cutting edge to the cutting edge, and the larger the blade thickness and blade back width e and the smaller the back angle θ, the stronger the supporting capacity of the blade back portion of the cutting edge to the cutting edge. The parameters have the same meaning as the parameters in the milling cutter standard; the relationship between the parameters of the first cutting tool cutting edge rake angle α, blade thickness f, blade thickness back angle θ, blade back width e and the disk diameter D1 and the number of cutting edges n1 of the first cutting tool 4 is preferably in accordance with the recommended values ​​in Table 1.

[0065] Table 1: Relationship between various parameters of the first cutting tool edge geometry

[0066] Spot welding material Rake angle α Blade thickness f Blade thickness back angle θ Width behind blade e Disc diameter D1 Number of cutting edges n1 Steel Plate 3～8° f≥0.2mm 15～25° ≥0.8mm ≥30 ≥32 Aluminum Plate 2.5～5° f≥0.3mm 15～25° ≥0.8mm ≥35 ≥34

[0067] like Figure 3-1 and Figure 3-2As shown, D2 is the inner diameter of the cutting edge ring of the first cutting tool 4, that is, the diameter of the third circular sink 10, and D1 is the outer diameter of the cutting edge ring; the difference between D1 and D2 is the ring width of the cutting edge ring, that is, the cutting edge width; because the large end diameter of the second cutting tool 5 or 17 is embedded in the sink of the first cutting tool 4 when the combined cutting tool is assembled, the value range of the inner diameter D2 of the ring of the first cutting tool 4 can be selected according to the large end diameter D5+0.10 mm of the second cutting tool 5 or 17; in order to ensure the strength of the cutting edge base part of the cutting tool, the total thickness h of the first cutting tool 4 is selected as ≧3 mm. From the perspective of chip removal, the cutting edge of the disc-shaped first cutting tool 4 is provided with a back rake angle ε, and the angle of the back rake angle ε is preferably between 10° and 15°.

[0068] In the present invention, since the electrode working end surface to be processed may be the arc surface electrode 13 or the truncated cone electrode 14, that is, the trajectory line of the side surface of the electrode working end may be the convex arc surface + straight line portion at the label 15 or the truncated cone surface at the label 16, therefore, Figure 7-1 The second cutting tool suitable for the electrode shown is Figure 4-1 and Figure 4-2 The arc cutting tool 5 shown, Figure 7-2 The second cutting tool suitable for the electrode shown is Figure 5-1 and Figure 5-2 The truncated cone shaped cutting tool 17 is shown.

[0069] If the second cutting tool is a curved cutting tool 5, the contour trajectory of its cutting edge is a combination of concave arc segments and straight line segments, such as Figure 4-1 and Figure 4-2 As shown; the arc segment radius of the arc cutting tool 5 in the contour trajectory line is equal to the arc radius r of the convex arc surface of the working end side of the arc electrode 13 to be cut and ground, and the straight surface is designed according to the tangent line of the arc curve corresponding to the central angle of 50 ° ± 10 ° when the expansion is, such as Figure 7-1 The contour trajectory of the arc surface cutting tool 5 is consistent with the arc surface curve 15 of the working end side of the arc surface electrode 13 to be cut and polished, and only bears the following Figure 7-1 The grinding of the outer convex arc surface + straight line portion 15 of the electrode working end side surface is shown. The radius of the arc segment of the arc cutting tool 5 is the same as the arc radius of the electrode to be ground at that location.

[0070] The arc surface cutting tool 5 includes several cutting edges of the same geometric shape, and its structural dimensions include the diameter D5 of the large end of the cutting tool, the diameter D3 of the small end of the cutting tool, and the number of cutting edges n2. Since the geometric dimensions of the cutting edges of the arc surface cutting tool 5 are relatively small and it is a multi-edge composite curved surface structure, from the perspective of convenient cutting tool manufacturing, the helix angle ω of the cutting edge of the arc surface cutting tool 5 can be limited to within the range of ≦5°; the relationship between the structural dimensions, the number of cutting edges, and the helix angle ω of the cutting edge of the arc surface cutting tool 5 and the electrode diameter R to be cut and ground is preferably in accordance with the recommended values ​​in Table 2.

[0071] Table 2: Relationship between the structural dimensions, number of cutting edges and helix angle of the arc surface second cutting tool 5

[0072] Electrode diameter R Cutting tool large end diameter D5 Small end diameter of cutting tool D3 Number of cutting edges n2 Helix angle ω 13mm ≥35mm ≥9mm 8 to 14 0～3° 16mm ≥43mm ≥11mm 14 to 20 0～4° 22mm ≥52mm ≥12mm 18 to 25 0～5°

[0073] If the second cutting tool is a truncated cone-shaped cutting tool 17, the cone angle of the truncated cone-shaped cutting tool 17 matches the cone angle of the side surface of the working end of the truncated cone-shaped electrode 11 to be cut and ground, and only bears the following Figure 7-2 Grinding of the conical surface 16 on the side surface of the working end of the truncated cone electrode.

[0074] like Figure 5-1 and Figure 5-2 As shown, the truncated cone-shaped cutting tool 17 includes several cutting edges of the same geometric shape; the structural dimensions of the truncated cone-shaped cutting tool 17 include the large end diameter D5 of the cutting tool, the small end diameter D3 of the cutting tool, and the number of cutting edges n3; because the truncated cone-shaped cutting tool 17 has better processing technology than the arc surface cutting tool 5, from the perspective of facilitating chip removal, the cutting edges of the truncated cone-shaped cutting tool 17 are all provided with a back rake angle ε, and the angle of the back rake angle ε is preferably between 10° and 15°. The relationship between the structural dimensions, the number of cutting edges, and the back rake angle ε of the cutting edge of the truncated cone-shaped cutting tool 17 and the electrode diameter R to be cut and ground is preferably in accordance with the recommended values ​​in Table 3.

[0075] Table 3: Relationship between the structural dimensions, number of cutting edges and back rake angle of the truncated cone-shaped second cutting tool 17

[0076] Electrode diameter R Cutting tool large end diameter D5 Small end diameter of cutting tool D3 Number of cutting edges n3 Caster angle ε 13mm ≥35mm ≥9mm 8 to 14 10～13° 16mm ≥43mm ≥11mm 14 to 18 11～14° 22mm ≥52mm ≥12mm 18 to 23 12～15°

[0077] The geometric shapes of the cutting edges of the first cutting tool 4, the arc cutting tool 5 and the truncated cone cutting tool 17 are described by the parameters of the cutting tool cutting edge rake angle α, back angle δ, blade thickness b and blade thickness back angle θ. Among them, the larger the cutting edge rake angle α, the sharper the cutting edge, but the load bearing capacity will be reduced accordingly; the back angle δ, blade thickness b and blade thickness back angle θ are parameters that jointly describe the support capacity of the back of the cutting edge to the cutting edge. The larger the cutting edge thickness b, the smaller the back angle δ and the blade thickness back angle θ, the stronger the support capacity of the back of the cutting edge to the cutting edge when the cutting edge is loaded; the relationship between the geometric parameters such as the cutting edge rake angle α, back angle δ, blade thickness b and blade thickness back angle θ is preferably in accordance with the recommended values ​​in Tables 4 and 5.

[0078] Recommended values ​​of structural parameters of the first cutting tool (4), the arc-surface cutting tool (5) and the truncated cone-shaped cutting tool (17) when used for spot welding of different materials are as follows:

[0079] (1) When the first cutting tool (4), the arc cutting tool (5) and the truncated cone cutting tool (17) are used for electrode grinding of spot welding steel plates, the geometric parameters of the cutting edge include the rake angle α, the back angle δ, the blade thickness f, the back width e and the blade thickness back angle θ, and the recommended values ​​of the relationship between the rake angle α, the back angle δ, the blade thickness f, the back width e and the blade thickness back angle θ are as follows:

[0080] Table 4: Structural parameters of the first cutting tool (4), the curved cutting tool (5) and the truncated cone cutting tool (17)

[0081] Rake angle α Back angle δ Blade thickness f Width behind blade e Blade thickness back angle θ 3～8° 8～12° ≥0.2mm ≥0.8mm 15～25°

[0082] (2) When the first cutting tool (4), the arc cutting tool (5) and the truncated cone cutting tool (17) are used for grinding electrodes for spot welding of aluminum or aluminum alloy, the geometric parameters of the cutting edge include the rake angle α, the back angle δ, the blade thickness f, the back width e and the blade thickness back angle θ, and the recommended values ​​of the relationship between the rake angle α, the back angle δ, the blade thickness f, the back width e and the blade thickness back angle θ are as follows:

[0083] Table 5: Structural parameters of the first cutting tool (4), the curved cutting tool (5) and the truncated cone cutting tool (17)

[0084] Rake angle α Back angle δ Blade thickness f Width behind blade e Blade thickness back angle θ 2.5～5° 8～12° ≥0.3mm ≥0.8mm 15～25°

[0085] like Figure 3-1 , Figure 4-1 and Figure 5-1 As shown, the axial hole diameters of the first cutting tool 4, the second cutting tool 5 or 17 are all represented by D4, which are the same as the axial hole diameter of the spur gear 2, and together form a clearance fit relationship with the outer diameter of the cutter shaft 1, and the axial hole fit clearance is selected as (0.01-0.02 mm). L is the total axial length of the arc cutting tool 5 or the truncated cone cutting tool 17, and the value range of L is based on the radius of the working end 12 of the arc surface electrode 13 to be ground (radius is Figure 7-1 Or D / 2 in 7-2) minus (0.5~1 mm) to select.

[0086] R is the arc radius of the arc portion of the arc cutting tool 5, and its value is equal to the arc radius r of the arc portion 9 of the working end side surface of the arc electrode 13 to be ground.

[0087] β1 is a safety angle set for the arc cutting tool 5 to avoid tool collision caused by electrode repeated positioning error; the β1 is designed as follows: an outward tangent is made from the midpoint of the arc radius R of the arc cutting tool 5 to ensure that "the difference between the length of the outward tangent and the arc radius ≧ the electrode repeated positioning accuracy" as the end point position of the cutting tool edge, and the angle between the outward tangent and the axis of the arc cutting tool 5 is the safety angle β1 of the arc cutting tool 5.

[0088] β2 is the angle between the inclination angle of the cone surface of the truncated cone cutting tool 17 and its axis, and its value is the same as the inclination angle of the side surface of the working end 12 of the truncated cone electrode 14; 2β2 is the cone angle of the working end 12 of the truncated cone electrode 14 to be ground, and is also the cone angle of the truncated cone cutting tool 17.

[0089] In the present invention, both the disc-shaped cutting tool of the first cutting tool 4 and the arc-shaped cutting tool 5 or the truncated cone-shaped cutting tool 17 of the second cutting tool are multi-edge cutting tools. Compared with the integrated single-edge cutting tools recommended for use in the known automatic electrode sharpener, the multi-edge cutting tool of the present invention has the advantages that the first cutting tool 4 and the second cutting tool 5 or 17 must be arranged in a circular manner. Figure 1-1 or Figure 1-2 In addition to the relationship between the two tools, the combined cutting tool must be used only after it is combined. The combined cutting tool must also be used to grind the electrode surface to be repaired in the form of revolution + rotation to achieve the expected grinding effect on the electrode working end face.

[0090] The so-called multi-edge cutting tool is compared with the cutting tool with only one cutting edge that is recommended for use in the prior art; Figure 3-1 to Figure 5-2 The number of cutting edges of the proposed multi-edge cutting tool is proportional to the diameter of the disc and inversely proportional to the cutting edge pitch between the cutting edges for the first cutting tool 4; for the arc-shaped cutting tool 5 or the truncated cone-shaped cutting tool 17, when the grinding object is a universal φ16 electrode, the minimum number of cutting edges is 14. The geometric features of the cutting edges of the second cutting tool 5 or 17 are all composite surfaces. The so-called composite surface of the cutting edge of the cutting tool means that the geometric shape of the cutting edge details of the cutting tool needs to be described by multiple dimensions and multiple angles listed in Tables 2 to 5. The disc-shaped cutting tool as the first cutting tool 4 is only responsible for cutting and grinding the flat part of the electrode working end 12 during the electrode grinding process; the arc cutting tool 5 or the truncated cone-shaped cutting tool 17 as the second cutting tool is only responsible for cutting and grinding the position marked 15 or 16 on the side surface of the electrode working end during the electrode grinding process, and the arc radius or cone angle to be ground are determined by the geometric shape and parameter size of the side surface of the working end of the electrode 13 or 14 to be ground.

[0091] Using the present invention as Figure 3-1 to Figure 5-2 Multi-edge cutting tools, and press Figure 1-1 Or 1-2 is combined into a combined cutting tool, which can create the following favorable conditions for the automatic electrode grinder: First, multiple cutting edges share the cutting load borne by a single cutting edge in the prior art, thereby increasing the service life of the cutting tool; second, since the cutting load of the cutting tool edge during the electrode cutting and grinding process is greatly reduced, the cutting tool edge can be made sharper, which creates the necessary conditions for grinding the electrode under the condition of micro-cutting amount, and further reduces the cutting stress of the cutting tool edge and increases the service life of the cutting tool.

[0092] Although the present invention has been described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can make many modifications without departing from the purpose of the present invention, all of which are within the protection of the present invention.

Claims

1. A combined cutting tool for an automatic grinding device for spot welding electrodes, comprising a cutting shaft (1), wherein the shaft end of the cutting shaft (1) is equipped with a spur gear (2); Features: One end of the cutter shaft (1) is provided with a flange (7), the inner surface of the flange (7) being used as a positioning base surface when the spur gear (2) is assembled therewith; the other end of the cutter shaft (1) is provided with a threaded hole (18) at its axis, the threaded hole (18) being used as a bolt assembly hole when the cutter shaft (1) is axially constrained; A first circular depression (6) is formed on the shaft end of the spur gear (2) along the axis, and the bottom surface of the first circular depression (6) serves as a positioning base surface after the cutter shaft (1) is inserted into the shaft hole of the spur gear (2); a second circular depression (8) is formed on the other side of the disk of the spur gear (2), and the first cutting tool (4) is fixedly installed in the second circular depression (8) by using two fixing pins (3), so that the two become a combined component; A second cutting tool is coaxially embedded in a third circular sink (10) centrally symmetrical on the first cutting tool (4); a key (11) is used to radially constrain and fix the spur gear (2) and the second cutting tool to the cutter shaft (1); The first cutting tool (4) is in the shape of a thin-walled circular disk; a plurality of identical cutting edges (9) with radial trajectory lines are evenly distributed relative to the center of the convex annular surface on the outer side of the second circular sink (8); and a plurality of cutting edges with the same geometric dimensions are formed along the axial outer side surface of the second cutting tool; The second cutting tool comprises a curved cutting tool (5) and a truncated cone-shaped cutting tool (17).

2. A combined cutting tool for an automatic grinding device for spot welding electrodes according to claim 1, Features: When the first cutting tool (4) rotates to grind the electrode to be cut, the rotation plane of its cutting edge always fits with the working end plane part (12) of the electrode to be cut, and only performs the grinding work of the working end plane part (12) of the electrode.

3. A combined cutting tool for an automatic grinding device for spot welding electrodes according to claim 1 or 2, Features: When the arc surface cutting tool (5) rotates to grind the electrode to be cut and ground, the contour trajectory of the cutting edge rotation fits the arc surface curve (15) on the side of the arc surface electrode (13), and only grinds the side of the working end of the arc surface electrode (13).

4. A combined cutting tool for an automatic grinding device for spot welding electrodes according to claim 3, Features: The contour trajectory line is composed of a concave arc segment and a straight line segment from the small end to the large end of the arc surface cutting tool (5); the radius of the arc segment is the same as the arc radius of the arc surface curve (15) in the electrode to be ground.

5. A combined cutting tool for an automatic grinding device for spot welding electrodes according to claim 1 or 2, Features: When the truncated cone-shaped cutting tool (17) rotates to grind the electrode to be cut, the contour trajectory of the rotating cutting edge fits the conical surface (16) on the side of the truncated cone-shaped electrode (14), and only grinds the side of the working end of the truncated cone-shaped electrode (14).

6. A combined cutting tool for an automatic grinding device for spot welding electrodes according to claim 5, Features: The cone angle of the truncated cone-shaped cutting tool (17) is the same as the cone angle of the cone surface (16) of the side surface of the working end of the truncated cone-shaped electrode (14) to be ground.

7. A combined cutting tool for an automatic grinding device for spot welding electrodes according to claim 1, 2, 4 or 6, Features: The first cutting tool (4) comprises a plurality of cutting edges (9) of the same geometric shape, and the relationship between the front angle α, the blade thickness f, the blade thickness back angle θ, the blade back width e, the disk diameter D1 and the number of cutting edges n1 of the cutting edge (9) and the spot welding material is as follows: 。 8. A combined cutting tool for an automatic grinding device for spot welding electrodes according to claim 4, Features: The arc surface cutting tool (5) comprises a plurality of cutting edges of the same geometric shape; the relationship between the cutting edge diameter D5, the cutting edge diameter D3, the number of cutting edges n2 and the cutting edge helix angle ω of the arc surface cutting tool (5) and the electrode diameter R of the arc surface electrode (13) to be cut and ground is as follows: 。 9. A combined cutting tool for an automatic grinding device for spot welding electrodes according to claim 6, Features: The truncated cone-shaped cutting tool (17) comprises a plurality of cutting edges of the same geometric shape; the relationship between the cutting edge diameter D5, the cutting edge diameter D3, the number of cutting edges n3 and the cutting edge back rake angle ε of the truncated cone-shaped cutting tool (17) and the electrode diameter R of the truncated cone-shaped electrode (14) to be cut and ground is as follows: 。 10. A combined cutting tool for an automatic grinding device for spot welding electrodes according to claim 8 or 9, Features: The structural parameters of the first cutting tool (4), the arc-surface cutting tool (5) and the truncated cone-shaped cutting tool (17) are selected according to the material to be spot welded: (1) When the first cutting tool (4), the arc-surface cutting tool (5) and the truncated cone-shaped cutting tool (17) are used for electrode grinding of spot-welded steel plates: The geometric parameters of the cutting edge include the front angle α, the back angle δ, the blade thickness f, the back width e and the back angle θ of the blade thickness. The recommended values ​​of the relationship between the front angle α, the back angle δ, the blade thickness f, the back width e and the back angle θ of the blade thickness are as follows: (2) When the first cutting tool (4), the arc-surface cutting tool (5) and the truncated cone-shaped cutting tool (17) are used for grinding electrodes for spot welding of aluminum or aluminum alloy: The geometric parameters of the cutting edge include the front angle α, the back angle δ, the blade thickness f, the back width e and the back angle θ of the blade thickness. The recommended values ​​of the relationship between the front angle α, the back angle δ, the blade thickness f, the back width e and the back angle θ of the blade thickness are as follows: 。

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