Additive-free sensor welding method

Abstract

The invention relates to an additive-free sensor welding method. The additive-free sensor welding method comprises the following steps that the welding ends of two leads of a sensor are in one-to-one corresponding contact with the welding ends of two wires of the sensor; current welding is carried out on the welding ends of the wires and the welding ends of the corresponding leads of the sensor, so that the welding ends of the wires and the welding ends of the corresponding leads of the sensor form pre-connection; and carrying out laser welding on the welding end of each wire, so that the welding end of each wire is fused and wraps the welding end of the corresponding lead of the sensor. According to the additive-free sensor welding method, the problem that bridging short circuit is likely to happen due to the fact that welding spots are too large in an existing sensor welding method is solved.

Description

Technical Field

[0001] The invention relates to the technical field of sensor welding, and in particular to an additive-free sensor welding method. Background Art

[0002] At present, the welding method generally used in the field of temperature sensors is resistance spot welding, which is to tin the leads and wire cores before resistance spot welding. Tinning will increase the cost of materials, turnover, labor, etc., and also have an impact on the environment. The welding process of tinning treatment has large solder joints, and the size of the solder joints is difficult to control, and it is easy to bridge and short-circuit between the two solder joints of the sensor. In addition, tinning spot welding has the risk of melting tin for sensors used in high temperature environments. Summary of the invention

[0003] The main purpose of the present invention is to provide an additive-free sensor welding method, which aims to solve the problem that the existing sensor welding method has too large solder joints, which easily leads to bridging short circuits.

[0004] To achieve the above object, the present invention provides a method for welding a sensor without additives, comprising the following steps:

[0005] Make the welding ends of the two leads of the sensor contact with the welding ends of the two wires one by one;

[0006] Performing current welding on the welding end of each of the wires and the welding end of the corresponding lead of the sensor, so that the welding ends of the two are pre-connected;

[0007] Laser welding is performed on the welding ends of the wires so that the welding ends of the wires melt and cover the welding ends of the corresponding leads of the sensors.

[0008] According to some embodiments of the present invention, before the welding ends of the two leads of the sensor are brought into contact with the welding ends of the two wires in a one-to-one correspondence, the method further includes:

[0009] Twisting the welding end of the wire to expose it;

[0010] Spot weld the wire ends after twisting to gather the wires.

[0011] According to some embodiments of the present invention, the step of twisting the welding end of the wire to expose the wire includes:

[0012] The wire is semi-stripped so that part of the wire skin is suspended on the welding end of the wire;

[0013] The wire sheath is rubbed in the same direction to tighten the multiple wire cores;

[0014] The wire sheath is cut to expose the tightened welding end of the wire.

[0015] According to some embodiments of the present invention, after laser welding the welding ends of each of the wires, the method further includes:

[0016] Obtain the coverage of the welded part and the ultimate tensile strength of the welded part after welding;

[0017] The quality of laser welding is checked based on the coverage and the ultimate tensile strength.

[0018] According to some embodiments of the present invention, the step of performing a qualified check on the laser welding quality according to the coverage and the ultimate tensile strength comprises:

[0019] When the coverage is equal to 100% and the ultimate tensile strength is not less than the designed tensile strength, the verification result is determined to be qualified; otherwise, the verification result is determined to be unqualified.

[0020] According to some embodiments of the present invention, after the quality of laser welding is checked according to the coverage and the ultimate tensile strength, the method further includes:

[0021] When the welding quality inspection result is unqualified, adjust the defocus amount and laser power;

[0022] Laser welding is performed on each new wire welding end using the adjusted laser parameters until the welding quality inspection result is qualified.

[0023] According to some embodiments of the present invention, adjusting the defocus amount and the laser power includes:

[0024] Increasing the defocus amount and performing laser melting on the new wire welding end with the adjusted laser parameters;

[0025] Conduct qualified verification of the stability of the molten pool after melting;

[0026] After the molten pool stability check result is qualified, increase the laser power.

[0027] According to some embodiments of the present invention, before laser welding is performed on the welding ends of each of the wires, the method further includes:

[0028] A shielding gas is blown into the welding end of each of the wires to reduce the oxygen content at the welding position to zero.

[0029] According to some embodiments of the present invention, the step of bringing the welding ends of the two leads of the sensor into contact with the welding ends of the two wires in a one-to-one correspondence includes:

[0030] Each lead welding end of the sensor is placed below the corresponding welding end of the wire so that the top surface of the lead welding end contacts the bottom surface of the wire welding end.

[0031] According to some embodiments of the present invention, the laser welding of the welding ends of each of the wires includes:

[0032] Laser welding is performed on a side of the welding end of each wire away from the welding end of the corresponding lead wire of the sensor.

[0033] The present invention has at least the following beneficial effects:

[0034] The present invention applies the additive-free sensor welding method to a laser welding system, and the additive-free sensor welding method includes: making the welding ends of the two leads of the sensor and the welding ends of the two wires contact one by one; performing current welding on the welding ends of each wire and the welding ends of the corresponding leads of the sensor, so that the welding ends of the two are pre-connected; performing laser welding on the welding ends of each wire, so that the welding ends of each wire melt and cover the welding ends of the corresponding leads of the sensor. The present invention first makes the welding ends of the two leads of the sensor contact with the welding ends of the corresponding two wires, and then performs current welding on the welding ends of each wire and the welding ends of the corresponding leads of the sensor, so that the welding ends of the two are pre-connected, so as to avoid biased welding in subsequent laser welding, resulting in an increase in the weld point, and then irradiating the laser to the welding end of the wire, heating the welding end by laser, so that the welding end melts to cover the welding end of the sensor lead, and realizes the welding of the sensor lead and the wire. Compared with the existing welding method that requires the use of solder to weld and fix the sensor lead and the wire, on the one hand, the fusion welding of the two metals in the present invention is smaller than the welding of three metals in the existing method, and the risk of bridging short circuit between the two welding points is less likely to occur. On the other hand, the sensor lead is wrapped by the fusion of the wire welding end, which is more firmly fixed than connecting the wire and the lead by soldering, and the material cost is lower. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 A schematic diagram of a wire twisting device twisting a wire in the additive-free sensor welding method provided in an embodiment of the present invention;

[0037] Figure 2 A schematic diagram of the spot welding equipment performing wire gathering and pre-connection on the wires in the additive-free sensor welding method provided in an embodiment of the present invention;

[0038] Figure 3A schematic diagram of laser melting welding of a wire and a sensor lead by a laser welding device in the additive-free sensor welding method provided in an embodiment of the present invention;

[0039] Figure 4 This is the cross-sectional view of the weld after laser welding is completed;

[0040] Figure 5 It is a schematic diagram of the process of the first embodiment of the additive-free sensor welding method of the present invention;

[0041] Figure 6 It is a schematic diagram of the flow chart of the second embodiment of the additive-free sensor welding method of the present invention;

[0042] Figure 7 It is a schematic flow chart of a third embodiment of the additive-free sensor welding method of the present invention;

[0043] Figure 8 It is a schematic flow chart of a fourth embodiment of the additive-free sensor welding method of the present invention;

[0044] Fig. 9 It is a schematic diagram of the flow chart of the fifth embodiment of the additive-free sensor welding method of the present invention;

[0045] Fig.10 It is a schematic flow chart of a sixth embodiment of the additive-free sensor welding method of the present invention;

[0046] Fig.11 It is a schematic flow chart of a seventh embodiment of the additive-free sensor welding method of the present invention;

[0047] Fig.12 It is a schematic flow chart of an eighth embodiment of the additive-free sensor welding method of the present invention;

[0048] Fig.13 It is a schematic flow chart of a ninth embodiment of the additive-free sensor welding method of the present invention;

[0049] Fig.14 It is a schematic flow chart of the tenth embodiment of the additive-free sensor welding method of the present invention.

[0050] Description of reference numerals:

[0051] 100-Laser welding equipment; 200-Wire rolling equipment; 300-Spot welding equipment; 400-Lead wire; 500-Wire. DETAILED DESCRIPTION

[0052] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0054] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in the field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0055] The present invention provides a sensor welding method without additives. Figures 1 to 14 The present invention provides a specific embodiment of an additive-free sensor welding method.

[0056] like Figures 2 to 5 As shown, an embodiment of the present invention provides a method for welding a sensor without an additive, comprising the following steps:

[0057] Step S30: The welding ends of the two sensor leads 400 and the welding ends of the two wires 500 are brought into contact with each other in a one-to-one correspondence.

[0058] It should be noted that the welding ends of the two lead wires 400 are in contact with the welding ends of the corresponding two wires 500 for subsequent welding process.

[0059] It should be noted that the wire core of the conductive wire 500 may be a single-strand wire core or a multi-strand wire core.

[0060] Step S40: current welding is performed on the welding end of each of the wires 500 and the welding end of the corresponding lead wire 400 of the sensor, so that the welding ends of the two are pre-connected.

[0061] It should be noted that the spot welding device 300 can be used to perform current welding on the welding ends of the wire 500 and the lead 400, so that the two welding ends are pre-connected, so as to avoid the phenomenon of biased welding due to relative movement of the two welding ends during subsequent laser welding. On the one hand, it causes the wire 500 to be unable to completely cover the welding end of the lead 400 after melting, and on the other hand, it causes the solder joint after welding to be larger, which is prone to bridging short circuit problems.

[0062] Step S60: laser welding is performed on the welding ends of the wires 500 so that the welding ends of the wires 500 are melted and cover the welding ends of the corresponding leads 400 of the sensors.

[0063] It should be noted that, in some embodiments, a single-mode laser is used to perform laser welding on the welding end. Compared with a multi-mode laser, a single-mode laser has a higher beam quality, a smaller beam diameter, a smaller divergence angle, and a stronger focusing ability, and is suitable for application scenarios such as the present invention that require high precision and high resolution.

[0064] It should be noted that the laser moves at a uniform speed in a direction perpendicular to the two wires 500 to perform laser welding on the welding ends of the two wires 500. Specifically, the collimation head of the laser welding equipment 100 can be moved in a direction perpendicular to the two wires 500 so that the emitted laser moves at a uniform speed along the welding path. A laser galvanometer can also be used to control the laser to move at a uniform speed on the welding path.

[0065] It should be noted that the welding end can be laser welded using a laser welding device 100, and the set power of the laser welding is adjusted according to the diameter and material of the wire 500. Generally, the larger the diameter of the wire 500, the greater the laser power, so that the welding end can absorb enough heat to melt.

[0066] The present invention conducts experiments on the diameters and materials of some commonly used wires 500 to obtain the preset laser power of the laser welding device 100. The comparison table is as follows:

[0067] Wire diameter Wire material Lead wire diameter Lead material Preset laser power 0.32mm copper 0.2mm Iron Nickel Alloy 400W 0.4mm copper 0.2mm Iron Nickel Alloy 480W 0.51mm copper 0.2mm Iron Nickel Alloy 500W 0.64mm copper 0.2mm Iron Nickel Alloy 550W 0.76mm Nickel-plated copper 0.2mm Iron Nickel Alloy 700W

[0068] The present invention applies the additive-free sensor welding method to a laser welding system, and the additive-free sensor welding method includes: making the welding ends of the two leads 400 of the sensor and the welding ends of the two wires 500 contact one by one; performing current welding on the welding end of each of the wires 500 and the welding end of the corresponding lead 400 of the sensor to form a pre-connection between the welding ends of the two; and performing laser welding on the welding end of each of the wires 500 to melt the welding end of each of the wires 500 and cover the welding end of the corresponding lead 400 of the sensor. The present invention first contacts the welding ends of the two leads 400 of the sensor with the welding ends of the corresponding two wires 500, then performs current welding on the welding ends of each of the wires 500 and the welding ends of the corresponding leads 400 of the sensor, so that the welding ends of the two are pre-connected, avoiding the occurrence of biased welding during subsequent laser welding, resulting in an increase in the welding point, and then irradiates the laser at the welding end of the wire 500, heats the welding end by laser, melts the welding end to cover the welding end of the sensor lead 400, and realizes the welding of the sensor lead 400 and the wire 500. Compared with the existing welding method that requires soldering to fix the sensor lead 400 and the wire 500, on the one hand, the melting welding of two metals in the present invention is smaller than the welding of three metals in the existing method, and the risk of bridging short circuit is not easy to occur between the two welding points. On the other hand, the sensor lead 400 is wrapped by the melting of the welding end of the wire 500, which is more firmly fixed than connecting the wire 500 and the lead 400 by soldering, and the material cost is lower.

[0069] refer to Figure 2 and Figure 6 , Figure 6 It is a schematic flow chart of the second embodiment of the additive-free sensor welding method of the present invention.

[0070] Based on the first embodiment, the sensor welding method without additives in this embodiment further includes, before step S30:

[0071] Step S10: Twisting the welding end of the wire 500 to expose it.

[0072] It should be noted that since the wire 500 is a multi-strand wire and is wrapped by an external wire sheath, the wire sheath needs to be cut to expose the welding end to facilitate subsequent current welding and laser welding. At the same time, in order to avoid the multi-strand wires spreading out after cutting the wire sheath, resulting in loose welding problems during welding, the wire 500 needs to be twisted so that the multi-strand wire core is tightened.

[0073] Step S20: spot welding the welding ends of the wires 500 after twisting.

[0074] It should be noted that the spot welding device 300 can be used to perform spot welding on the welding end to gather the multiple wire cores of the wire 500 together to prevent the single wire core from spreading out during subsequent current welding.

[0075] It should be noted that the spot welding wire gathering process and the current welding process can be performed separately in two operations, or the spot welding device 300 can be used to complete the wire gathering and current welding processes at one time.

[0076] In this embodiment, the multiple strands of wire 500 are first twisted and tightened, and the wire sheath covering the welding end is cut. The welding end of the twisted wire 500 is then spot welded to avoid the problem of loose welding due to the single wire core spreading out in subsequent processes. Then, the welding end of each wire 500 and the welding end of the corresponding lead 400 of the sensor are current welded to form a pre-connection between the two welding ends. Finally, the welding end of each wire 500 is laser welded to melt the welding end of each wire 500 and cover the welding end of the corresponding lead 400 of the sensor to achieve the connection and fixation of the wire 500 and the lead 400.

[0077] refer to Figure 1 and Figure 7 , Figure 7 It is a schematic flow chart of the third embodiment of the additive-free sensor welding method of the present invention.

[0078] Based on the above second embodiment, the additive-free sensor welding method of this embodiment includes, in step S10:

[0079] Step S11: half-stripping the wire 500 so that part of the wire skin is hung on the welding end of the wire 500 .

[0080] Step S12: Twisting the wire sheath in the same direction to tighten the multiple wire cores.

[0081] It should be noted that the wire 500 can be twisted using a wire twisting device 200, which includes two wire twisting modules arranged relatively to each other in the up and down directions, and the two wire twisting modules cooperate with each other to form a fixed clamping groove for the wire skin to extend into, and one of the wire twisting modules moves in the horizontal direction relative to the other wire twisting module, so that the wire skin rotates relative to the other end of the wire 500, thereby tightening the multi-strand wire cores at the welding end.

[0082] Preferably, each of the thread twisting modules is provided with a thread twisting tooth on one side facing the other thread twisting module, and the thread twisting teeth are inclined in the horizontal direction with an inclination angle of 45°. Such an arrangement prevents the thread skin from moving relative to the thread twisting module during thread twisting, thereby affecting the thread twisting effect.

[0083] Step S13: cutting the wire sheath to expose the welding end of the tightened wire 500.

[0084] In this embodiment, the wire 500 is first half-stripped so that part of the wire skin is suspended on the welding end of the wire 500, and then the wire skin is clamped by the two wire twisting modules, one of the wire twisting modules moves in the horizontal direction relative to the other wire twisting module, so that the wire skin rotates relative to the other end of the wire 500, so that the multiple wire cores at the welding end are tightened, and finally the wire skin is cut to expose the tightened welding end of the wire 500 for subsequent current welding and laser welding.

[0085] refer to Figure 8 , Figure 8 It is a schematic flow chart of the fourth embodiment of the additive-free sensor welding method of the present invention.

[0086] Based on the first embodiment, the sensor welding method without additives in this embodiment further includes, after step S60:

[0087] Step S70: Obtain the coverage of the welded part and the ultimate tensile strength of the welded part after welding is completed.

[0088] It should be noted that if Figure 4 As shown in the figure, the cross-sectional image after welding can be obtained through high-precision visual CCD, and AI vision can be used to teach through a large amount of data pictures to detect the coverage after welding.

[0089] Step S80: performing a quality check on the laser welding according to the coverage and the ultimate tensile strength.

[0090] It should be noted that after the laser welding is completed, the quality of the laser welding is determined by checking the coverage and the ultimate tensile strength.

[0091] In this embodiment, after the laser melting welding is completed, a cross-sectional image after the welding is completed is obtained by a high-precision visual CCD, and AI vision is used to teach through a large amount of data pictures to detect the coverage after welding, and a tensile gauge is used to detect the ultimate tensile strength of the weld. The coverage and the ultimate tensile strength are verified to determine the quality of laser welding.

[0092] refer to Fig. 9 , Fig. 9 It is a schematic flow chart of the fifth embodiment of the additive-free sensor welding method of the present invention.

[0093] Based on the fourth embodiment, the sensor welding method without additives in this embodiment includes, in step S80:

[0094] Step S81: When the coverage is equal to 100% and the ultimate tensile strength is not less than the designed tensile strength, the verification result is determined to be qualified; otherwise, the verification result is determined to be unqualified.

[0095] It should be noted that the designed tensile strength value is determined according to the diameter of the wire 500 , and the larger the diameter, the larger the designed tensile strength value.

[0096] In this embodiment, after the laser melting welding is completed, a cross-sectional image after the welding is completed is obtained through a high-precision visual CCD, and AI vision is used to teach through a large amount of data pictures to detect the coverage after welding, and a tensile gauge is used to detect the ultimate tensile strength of the weld. When the coverage is equal to 100% and the ultimate tensile strength is not less than the designed tensile strength, the verification result is judged to be qualified, otherwise the verification result is judged to be unqualified.

[0097] refer to Fig.10 , Fig.10 It is a schematic flow chart of the sixth embodiment of the additive-free sensor welding method of the present invention.

[0098] Based on the fourth embodiment, the sensor welding method without additives in this embodiment further includes, after step S80:

[0099] Step S90: When the welding quality inspection result is unqualified, adjust the defocus amount and laser power.

[0100] It should be noted that the defocus amount is the distance between the welding position and the focus, and the position of the wire 500 can be adjusted by adjusting the upper and lower servo motors to adjust the defocus amount.

[0101] Step S100: laser welding is performed on the welding ends of each new wire 500 using the adjusted laser parameters until the welding quality inspection result is qualified.

[0102] In this embodiment, after the laser melting welding is completed, a cross-sectional image after the welding is completed is obtained by a high-precision visual CCD, and AI vision is used to teach through a large amount of data pictures to detect the coverage after welding, and a tensile gauge is used to detect the ultimate tensile strength of the weld. The laser welding quality is checked for qualification based on the coverage and the ultimate tensile strength. When the welding quality check result is unqualified, the defocus amount and laser power are adjusted, and laser welding is performed on the new welding ends of each wire 500 with the adjusted laser parameters until the welding quality check result is qualified.

[0103] refer to Fig.11 , Fig.11 It is a schematic flow chart of the seventh embodiment of the additive-free sensor welding method of the present invention.

[0104] Based on the sixth embodiment, the sensor welding method without additives in this embodiment includes, in step S90:

[0105] Step S91: increasing the defocus amount and performing laser melting on the welding end of the new wire 500 with the adjusted laser parameters.

[0106] It should be noted that by increasing the defocusing amount, the heating area of ​​the welding end of the wire 500 can be increased, thereby increasing the area of ​​the molten pool after melting to increase the coverage.

[0107] Step S92: Perform a qualified check on the stability of the molten pool after melting.

[0108] It should be noted that the experimenter can use an electron microscope to observe the molten pool after melting, and judge the surface flatness of the molten pool based on experience. When the surface flatness of the molten pool is high, it can be determined that the stability of the molten pool is qualified.

[0109] Step S93: After the molten pool stability check result is qualified, increase the laser power.

[0110] It should be noted that by increasing the laser power, the laser energy absorbed by the conductor 500 can be increased, so that more wire cores are melted to increase the coverage.

[0111] It should be noted that by slowing down the laser welding speed, the time for the wire 500 to absorb energy can be prolonged, and the laser energy absorbed by the wire 500 can also be increased, so that more wire cores are melted to increase the coverage.

[0112] In this embodiment, after the laser melting welding is completed, a cross-sectional image after the welding is completed is obtained by a high-precision visual CCD, and AI vision is used to teach through a large amount of data pictures to detect the coverage after welding, and a tensile gauge is used to detect the ultimate tensile strength of the weld. The laser welding quality is checked for qualification based on the coverage and the ultimate tensile strength. When the welding quality check result is unqualified, the defocus amount is increased and the laser melting of the new wire 500 welding end is performed with the adjusted laser parameters, and the stability of the molten pool after melting is checked for qualification. After the molten pool stability check result is qualified, the laser power is increased, and the laser welding of each new wire 500 welding end is performed with the adjusted laser parameters until the welding quality check result is qualified.

[0113] refer to Fig.12 , Fig.12 It is a schematic flow chart of the eighth embodiment of the additive-free sensor welding method of the present invention.

[0114] Based on the first embodiment, the sensor welding method without additives in this embodiment further includes, before step S60:

[0115] Step S50: Blowing a protective gas into the welding end of each of the wires 500 to reduce the oxygen content at the welding position to zero.

[0116] It should be noted that if there is oxygen at the welding position, during the laser welding process, the wire 500 will undergo a high-temperature oxidation reaction to produce impurities, resulting in explosion points during the melting stage of the wire core, and further causing the wire 500 to be insufficiently melted or directly melted. Therefore, it is necessary to blow a protective gas into the welding position to avoid oxidation reaction of the wire core.

[0117] Specifically, the protective gas may be nitrogen or argon. In addition, the coaxial blowing method is adopted, and compared with the side-blowing method, the effective range is more precise.

[0118] In this embodiment, the welding ends of the two leads 400 of the sensor and the welding ends of the two wires 500 are respectively contacted one by one, and then the welding ends of the wires 500 are welded with the welding ends of the corresponding leads 400 of the sensor by current, so that the welding ends of the two are pre-connected, and then a protective gas is blown into the welding ends of the wires 500 to reduce the oxygen content at the welding position to zero, so as to prevent the wires 500 from being oxidized during the subsequent laser welding process. Finally, the welding ends of the wires 500 are laser welded to melt the welding ends of the wires 500 and cover the welding ends of the corresponding leads 400 of the sensor, so as to achieve a fixed connection between the wires 500 and the corresponding leads 400 of the sensor.

[0119] refer to Fig.13 , Fig.13 It is a flow chart of the ninth embodiment of the additive-free sensor welding method of the present invention.

[0120] Based on the first embodiment, the sensor welding method without additives in this embodiment includes, in step S30:

[0121] Step S31: placing the welding end of each lead 400 of the sensor below the corresponding welding end of the wire 500 so that the top surface of the welding end of the lead 400 contacts the bottom surface of the welding end of the wire 500.

[0122] It should be noted that the welding ends of each lead 400 of the sensor are placed below the corresponding welding ends of the wires 500. When the wires 500 absorb laser energy and melt, under the action of gravity, the molten wire core flows downward along its circumferential side to cover the welding ends of the corresponding leads 400 of the sensor, without the need to use additional components to drive the molten wire core to cover the welding ends of the leads 400.

[0123] In this embodiment, the welding end of each lead 400 of the sensor is placed below the welding end of the corresponding wire 500 so that the top surface of the welding end of the lead 400 contacts the bottom surface of the welding end of the wire 500, and then the welding end of each wire 500 is welded to the welding end of the corresponding lead 400 of the sensor by current so that the welding ends of the two are pre-connected, and then the welding end of each wire 500 is laser welded. When the welding end of the wire 500 absorbs laser energy and melts, the molten wire core flows downward along its circumferential side under the action of gravity to cover the welding end of the corresponding lead 400 of the sensor, so as to achieve a fixed connection between the wire 500 and the corresponding lead 400 of the sensor.

[0124] refer to Fig.14 , Fig.14 It is a schematic flow chart of the tenth embodiment of the additive-free sensor welding method of the present invention.

[0125] Based on the ninth embodiment, the sensor welding method without additives in this embodiment includes, in step S60:

[0126] Step S61: laser welding is performed on the side of the welding end of each of the wires 500 away from the welding end of the corresponding lead 400 of the sensor.

[0127] It should be noted that since the welding end of the wire 500 is away from the side of the welding end of the sensor corresponding lead 400 and the number of wire cores between the welding end of the lead 400 is greater, after laser melting, multiple wire cores in a molten state flow downward along the circumferential side to cover the welding end of the sensor corresponding lead 400, thereby improving the covering effect of the welding end of the lead 400 and thereby improving the welding quality.

[0128] In this embodiment, the welding end of each lead 400 of the sensor is placed below the welding end of the corresponding wire 500 so that the top surface of the welding end of the lead 400 contacts the bottom surface of the welding end of the wire 500, and then the welding end of each wire 500 is welded with the welding end of the corresponding lead 400 of the sensor by current so that the welding ends of the two are pre-connected, and then the welding end of each wire 500 away from the welding end of the corresponding lead 400 of the sensor is laser welded. When the welding end of the wire 500 absorbs laser energy and melts, the molten wire core flows downward along its circumferential side under the action of gravity to cover the welding end of the corresponding lead 400 of the sensor, so as to achieve a fixed connection between the wire 500 and the corresponding lead 400 of the sensor.

[0129] It should be understood that, although the various steps in the flowchart in the embodiment of the present application are displayed in sequence according to the indication of the arrows, these steps are not necessarily performed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and it can be performed in other orders. Moreover, at least a portion of the steps in the figure may include a plurality of sub-steps or a plurality of stages, and these sub-steps or stages are not necessarily performed at the same time, but can be performed at different times, and their execution order is not necessarily performed in sequence, but can be performed in turn or alternately with other steps or at least a portion of the sub-steps or stages of other steps.

[0130] It should be understood that the above is only an example and does not constitute any limitation on the technical solution of the present invention. In specific applications, technicians in this field can make settings as needed, and the present invention does not limit this.

[0131] It should be noted that the workflow described above is merely illustrative and does not limit the scope of protection of the present invention. In practical applications, technicians in this field can select part or all of them according to actual needs to achieve the purpose of the present embodiment, and no limitation is made here.

[0132] In addition, it should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or system. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or system including the element.

[0133] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0134] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A sensor welding method without additives, characterized in that: The following steps are involved: Make the welding ends of the two leads of the sensor contact with the welding ends of the two wires one by one; Performing current welding on the welding end of each of the wires and the welding end of the corresponding lead of the sensor, so that the welding ends of the two are pre-connected; Laser welding is performed on the welding ends of the wires so that the welding ends of the wires melt and cover the welding ends of the corresponding leads of the sensors.

2. The additive-free sensor welding method according to claim 1, characterized in that: Before the welding ends of the two leads of the sensor are brought into contact with the welding ends of the two wires in a one-to-one correspondence, the method further includes: Twisting the welding end of the wire to expose it; Spot weld the wire ends after twisting to gather the wires.

3. The additive-free sensor welding method according to claim 2, characterized in that: The step of twisting the welding end of the wire to expose it includes: The wire is semi-stripped so that part of the wire skin is suspended on the welding end of the wire; The wire sheath is rubbed in the same direction to tighten the multiple wire cores; The wire sheath is cut to expose the tightened welding end of the wire.

4. The additive-free sensor welding method according to claim 1, characterized in that: After laser welding the welding ends of each of the wires, the method further comprises: Obtain the coverage of the welded part and the ultimate tensile strength of the welded part after welding; The quality of laser welding is checked based on the coverage and the ultimate tensile strength.

5. The additive-free sensor welding method according to claim 4, characterized in that: The quality check of laser welding according to the coverage and the ultimate tensile strength includes: When the coverage is equal to 100% and the ultimate tensile strength is not less than the designed tensile strength, the verification result is determined to be qualified; otherwise, the verification result is determined to be unqualified.

6. The additive-free sensor welding method according to claim 4, characterized in that: After the quality of laser welding is checked according to the coverage and the ultimate tensile strength, the method further includes: When the welding quality inspection result is unqualified, adjust the defocus amount and laser power; Laser welding is performed on each new wire welding end using the adjusted laser parameters until the welding quality inspection result is qualified.

7. The additive-free sensor welding method according to claim 6, characterized in that: The adjusting of the defocus amount and the laser power comprises: Increasing the defocus amount and performing laser melting on the new wire welding end with the adjusted laser parameters; Conduct qualified verification of the stability of the molten pool after melting; After the molten pool stability check result is qualified, increase the laser power.

8. The additive-free sensor welding method according to claim 1, characterized in that: Before laser welding the welding ends of each of the wires, the method further comprises: A shielding gas is blown into the welding end of each of the wires to reduce the oxygen content at the welding position to zero.

9. The additive-free sensor welding method according to claim 1, characterized in that: The step of making the welding ends of the two leads of the sensor contact with the welding ends of the two wires in a one-to-one correspondence includes: Each lead welding end of the sensor is placed below the corresponding welding end of the wire so that the top surface of the lead welding end contacts the bottom surface of the wire welding end.

10. The additive-free sensor welding method according to claim 9, characterized in that: The laser welding of the welding ends of each of the wires comprises: Laser welding is performed on a side of the welding end of each wire away from the welding end of the corresponding lead wire of the sensor.

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