A resistance welding device for precision parts welding and a control method of a resistance automatic welding device

Abstract

The present invention discloses a resistance welding device and a control method for precision parts welding, the resistance welding device comprises a fixed seat for carrying a workpiece to be welded and installing a first electrode; a movable seat moves relative to the fixed seat through a driving structure, and is equipped with a second electrode and a detection component; the driving structure comprises a plurality of fixed magnetic parts and a moving magnetic part, each of which is laid on a frame at intervals along the trajectory of the moving seat movement, and forms a movement channel; the moving magnetic part falls on the movement channel and is displaced, and is installed with the movable seat; the detection component is used to detect welding pressure and welding depth; the detection component comprises a pressure detection part and a displacement detection part; the pressure detection part is used to detect the force of the second electrode on the movable part acting on the workpiece to be welded; the displacement detection part is used to detect the displacement of the second electrode during welding; the resistance welding device and the control method provided by the present invention solve the defects that the movement mode of the resistance welding device is rigid and inconvenient to use.

Description

Technical Field

[0001] The invention relates to the field of resistance welding equipment manufacturing, and in particular to a resistance welding device for precision parts welding and a control method for a resistance automatic welding device. Background Art

[0002] Nowadays, welding technology and welding equipment are widely used, from heavy shipbuilding and heavy industry to electric vehicle busbar conductive sheets;

[0003] At present, the existing metal parts have increasingly higher requirements for welding technology, especially the precision parts or thin-sheet parts used in some special occasions, which have high requirements for welding, and the existing resistance welding equipment can no longer meet the needs of precision parts welding, as follows: (1) The welding device of the existing resistance welding equipment is controlled to be fixed, and a cylinder or hydraulic cylinder is used to drive the welding station to move, that is, the stroke is only at position A and position B. The impact force driven by the cylinder during movement is too large, which can easily cause impact damage to the products to be welded placed on the fixed seat, and it is difficult to adjust the movement speed, which eventually leads to collision with the products to be welded and damage to the products, that is, the movement speed is too fast, the impact force is too large, and the products are flattened; or the movement speed is too slow, which affects the welding efficiency, and even leads to the inability to perform effective welding; if it is adjusted manually, it is time-consuming and labor-intensive, and requires professional welding technicians to adjust, and each type of product to be welded (1) The products to be welded are different, and the quality of the same product is also different. The thickness of the raw materials of some products is slightly thicker or thinner, which eventually leads to the risk of being unable to weld or being deformed by pressure. This is one of the reasons. (2) The quality of the product cannot be guaranteed after welding. In other words, mass production cannot guarantee the quality of each product. Most of these products are used in important occasions, such as electric vehicles and motor vehicles. Each product needs to be guaranteed to be a qualified product. However, it is difficult to detect whether there are defects in the appearance of the existing welding device after welding. It is necessary to pass multiple subsequent inspection processes, multiple inspection equipment, and multiple fixtures to complete the inspection. It is impossible to deduce whether it meets the quality requirements from the data of the welding process. For example, when the electrode surface is dirty, there are foreign objects on the product surface, and there is deformation at the welding position on the product, it is difficult for the welder to distinguish the welding defects caused by the above situations after welding.

[0004] In summary, how to improve the above-mentioned problems is also the technical difficulty that the applicant wants to solve. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned defects or problems existing in the background technology, and to provide a resistance welding device for precision parts welding and a control method for a resistance automatic welding device, which has a simple structure, is easy to manufacture, easy to implement and has low cost, and solves the defects of the resistance welding device in that the movement mode is rigid and inconvenient to use.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A resistance welding device for welding precision parts, the resistance welding device comprising a frame, a fixed seat mounted on the frame, a movable seat, a driving structure and a detection component;

[0008] A fixing seat, used for carrying the product to be welded and installing the first electrode;

[0009] A movable seat, which moves relative to the fixed seat through the driving structure and is equipped with a second electrode and a detection component;

[0010] The driving structure includes a plurality of fixed magnetic parts and moving magnetic parts, each of which is laid on the frame at intervals along the trajectory of the moving seat, and forms a moving channel; the moving magnetic part falls on the moving channel for displacement, and is mounted on the moving seat;

[0011] A detection component is used to detect welding pressure and welding depth; the detection component includes a pressure detection component and a displacement detection component respectively mounted on a movable seat; the pressure detection component is used to detect the force exerted by the second electrode on the movable component on the object to be welded; the displacement detection component is used to detect the displacement of the second electrode during welding.

[0012] Furthermore, the movable seat is separately arranged, and includes a welding unit and a mounting unit that cooperate with each other. The mounting unit is connected to the dynamic magnetic part of the driving structure and is restricted from moving relative to the fixed seat along the frame by a first guide assembly; the welding unit is driven by the mounting unit and moves relative to the fixed seat by the action of the second guide assembly; wherein the pressure detection component is installed between the mounting unit and the welding unit.

[0013] Furthermore, the movable seat also includes a spring, one end of which abuts against the mounting unit, and the other end acts on the pressure detection member.

[0014] Furthermore, the displacement detection component includes a photosensitive component and a grating ruler, the photosensitive component is installed on the side of the welding unit; the grating ruler is fixed to the frame and arranged opposite to the photosensitive component.

[0015] Furthermore, the first guide component is used for the attachment unit to move linearly relative to the frame and along the movement channel; the first guide component includes a guide groove and a boss, the guide groove is opened on the frame and the boss passes through; the boss is formed on the attachment unit; wherein, the attachment unit moves through the cooperation of the moving magnetic part and the fixed magnetic part, and the boss and the guide groove limit the linear displacement, so that the boss presses the spring, the pressure detection part, and the welding unit to move toward the fixed seat.

[0016] Furthermore, the second guide assembly includes a slide and a guide rail; the guide rail is mounted on the frame and allows the slide to move thereon; the slide is fixed to the welding unit; wherein the slide slides along the guide rail to limit the linear movement of the welding unit relative to the fixed seat.

[0017] Furthermore, it also includes a hollow frame and two limit members for limiting the distortion of the spring, wherein the hollow frame is fixedly connected to the boss; the two limit members are respectively installed in the hollow frame and are provided for the two ends of the spring to be sleeved; wherein the limit member at one end away from the boss is connected to the pressure detection member.

[0018] A welding method of a resistance automatic welding device, which controls the speed-changing displacement of a moving magnetic part in a linear motion channel formed between a plurality of fixed magnetic parts by changing the power-on time or current of the fixed magnetic part, and slowly displaces the moving magnetic part when the second electrode approaches the workpiece to be welded;

[0019] When the second electrode of the pressure detection component contacts the workpiece to be welded, the pressure value is collected and stored, and if the pressure values ​​collected for the artificially set number of times before the pressure value collected this time are all smoothly rising, then the pressure value collected this time is determined to be the pressure base value; and the displacement value collected by the displacement detection component at the time of obtaining the initial pressure value is calibrated as the base value of the depth of this welding and stored;

[0020] After the artificially set pressure value is added to the pressure base value, the first and second electrodes are energized for welding;

[0021] During welding, the pressure value and the displacement value are collected, stored and compared every manually set first period; in the second period, the pressure values ​​and displacement values ​​obtained in each first period are summarized to generate a real-time envelope curve, and the real-time envelope curve is compared with the manually set envelope curve interval. If any pressure value and / or displacement value in the real-time envelope curve exceeds the manually set envelope curve interval, the weld is determined to be an abnormal weld.

[0022] Furthermore, the smooth rising change is configured to determine that the first and second electrodes are energized and welded if the pressure value collected the previous manually set number of times of the pressure value collected this time is greater than the manually set value, or if the difference between the pressure value collected this time and the moving average pressure value of the previous manually set number of times is greater than the manually set value.

[0023] From the above description of the present invention, it can be seen that compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) The present invention provides a resistance welding device for precision parts welding and a control method for a resistance automatic welding device, which has a simple structure, is easy to manufacture, easy to implement and has low cost, and solves the defects of the resistance welding device in that the movement mode is rigid and inconvenient to use. The present invention adopts a fixed magnetic part and a moving magnetic part arranged in a straight line to achieve variable speed movement of the linear motion, and changes the fast movement to slow displacement when approaching the product to be welded, and can obtain the welding pressure value and the welding displacement value through the detection component, and judge whether the welded product is a qualified part through the pressure value and the displacement value. It is suitable for products with high welding precision requirements and thin parts, and the quality of batch welded products is close, so unqualified welded products can be selected efficiently.

[0025] (2) The present invention adopts a split welding unit and a mounting unit to form a movable seat, and the two are respectively limited in linear motion by two sets of guide components, so that the movement is faster and more convenient, the overall stability is better, and it is not easy to have deviations during the precision welding process, which helps to improve the welding quality;

[0026] (3) The present invention is also equipped with a spring, through the action of the spring, the pressure detection element can detect the pressure value more accurately, and through the action of the spring, the reaction force when touching the product to be welded is alleviated, and at the same time, the pressure detection element triggers the detection more quickly;

[0027] (4) The present invention uses a grating ruler for detection, which can sense the slight distance changes of precision welding and provide more accurate data, achieving a good detection effect and providing more accurate data for subsequent welding quality detection;

[0028] (5) The present invention also provides a limiter and a hollow frame for limiting the movement of the spring, thereby reducing the distortion of the spring due to the force direction problem and reducing the probability of detection data errors;

[0029] (6) The control method described in the present invention can achieve fast and uniform quality welding during the welding process of precision parts, and can automatically find the welding position (i.e., detect the pressure and depth through the pressure detection component and the displacement detection component), and automatically adjust its initial welding pressure. When the thickness of the welded parts is different and the surface is deformed, the initial pressure can be adjusted automatically, breaking the limitations of the traditional welding process, so that the quality of the welded product is better and the connectivity is better. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 It is a schematic diagram of the three-dimensional exploded structure of the resistance welding device of the present invention;

[0032] Figure 2 It is a schematic diagram of the three-dimensional structure of the resistance welding device of the present invention;

[0033] Figure 3 This is a schematic diagram of the detection component detection of the present invention. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are preferred embodiments of the present invention and should not be regarded as excluding other 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.

[0035] In the claims, description and drawings of the present invention, unless otherwise clearly defined, the use of terms such as "first", "second" or "third" etc. are intended to distinguish different objects rather than to describe a specific order.

[0036] In the claims, specification and the above-mentioned drawings of the present invention, unless otherwise explicitly defined, directional words, such as the use of terms such as "center", "lateral", "longitudinal", "horizontal", "vertical", "top", "bottom", "inside", "outside", "up", "down", "front", "back", "left", "right", "clockwise", "counterclockwise" and the like to indicate directions or positional relationships are based on the directions and positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the specific protection scope of the present invention.

[0037] In the claims, specification and the above drawings of the present invention, unless otherwise clearly defined, if the term "fixed connection" or "fixed connection" is used, it should be understood in a broad sense, that is, any connection method without a displacement relationship and relative rotation relationship between the two parties, that is to say, including non-detachable fixed connection, detachable fixed connection, integrated connection and fixed connection through other devices or elements.

[0038] In the claims, description and drawings of the present invention, if the terms "include", "have" and their variations are used, they are intended to mean "including but not limited to".

[0039] See also Figure 1-3The present invention discloses a resistance welding device for precision parts welding, the resistance welding device comprises a frame 1, a fixed seat 2 mounted on the frame 1, a movable seat 3, a driving structure 4 and a detection component 5;

[0040] A fixing seat 2, used for carrying the product to be welded and installing the first electrode A;

[0041] The movable seat 3 moves relative to the fixed seat 2 through the driving structure 4, and is equipped with a second electrode B and a detection component 5; it should be noted that the movable seat 3 described in the present invention is separately arranged, and includes a welding unit 31 and a mounting unit 32 that cooperate with each other, the mounting unit 32 is connected to the moving magnetic part 41 of the driving structure 4, and is restricted by the first guide component 6 and moves relative to the fixed seat 2 along the frame 1; the welding unit 31 is driven by the mounting unit 32, and moves relative to the fixed seat 2 by the second guide component 7; wherein the pressure detection component 51 is installed between the mounting unit 32 and the welding unit 31; the movable seat 3 also includes a spring 9, one end of which is against the mounting unit 32, and the other end acts on the pressure detection component 51.

[0042] The driving structure 4 includes a plurality of fixed magnetic members 42 and a moving magnetic member 41. The fixed magnetic members 42 are laid on the frame 1 at intervals along the moving track of the movable seat 3 to form a moving channel C. The moving magnetic member 41 falls on the moving channel C to move and is connected to the movable seat 3.

[0043] A detection assembly 5, which is used to detect welding pressure and welding depth; the detection assembly 5 includes a pressure detection member 51 and a displacement detection member 52 respectively mounted on the movable seat 3;

[0044] The pressure detection member 51 is used to detect the force exerted by the second electrode B on the movable member on the object to be welded;

[0045] The displacement detection component 52 is used to detect the displacement of the second electrode B during welding. The displacement detection component 52 of the present invention includes a photosensitive component 521 and a grating ruler 522. The photosensitive component 521 is installed on the side of the welding unit 31. The grating ruler 522 is fixed to the frame 1 and is arranged opposite to the photosensitive component 521.

[0046] More specifically, the first guide assembly 6 is used for the linear displacement of the attachment unit 32 along the motion channel C relative to the frame 1; the first guide assembly 6 includes a guide groove 61 and a boss 62, the guide groove 61 is opened on the frame 1, and the boss 62 passes through; the boss 62 is formed on the attachment unit 32; wherein, the attachment unit 32 moves through the cooperation between the moving magnetic part 41 and the fixed magnetic part 42, and the linear displacement is limited by the boss 62 and the guide groove 61, so that the boss 62 presses the spring 9, the pressure detection part 51, and the welding unit 31 to move toward the fixed seat 2.

[0047] More specifically, the second guide assembly 7 includes a slide 71 and a guide rail 72; the guide rail 72 is mounted on the frame 1 and allows the slide 71 to move thereon; the slide 71 is fixed to the welding unit 31; wherein the slide 71 slides along the guide rail 72 to limit the linear movement of the welding unit 31 relative to the fixed seat 2.

[0048] More specifically, it also includes a hollow frame 91 and two limit members 92 for limiting the distortion of the spring 9. The hollow frame 91 is fixedly connected to the boss 62. The two limit members 92 are respectively installed in the hollow frame 91 and are provided for the two ends of the spring 9 to be sleeved. The limit member 92 at one end away from the boss 62 is locked to the pressure detection member 51.

[0049] For specific implementation, see Figure 1-3 The resistance welding device for precision parts welding described in the present invention mainly includes the following components: a fixed seat 2 of a frame 1, a movable seat 3, a first electrode A, a second electrode B, a welding unit 31, an attachment unit 32, a moving magnetic part 41, a fixed magnetic part 42, a pressure detection part 51, a light sensing part 521, a grating ruler 522, a slide seat 71, a guide rail 72, a spring 9, a hollow frame 91 and two limit members 92;

[0050] During actual assembly:

[0051] (1) The fixing seat 2 is mounted on the frame 1 through a locking piece. It should be noted that the fixing seat 2 is a metal fixing seat 2 on which a jacket 20 for clamping the first electrode A is provided;

[0052] (2) Install the driving structure 4, and fix the base on which the fixed magnetic members 42 are placed to the frame 1. It should be noted that the fixed magnetic members 42 are arranged in two rows in a straight line, and a movement channel C is formed in the middle for the moving magnetic member 41 to move;

[0053] (3) The moving magnetic member 41 is mounted on the attachment unit 32, and the boss 62 on the attachment unit 32 passes through the guide groove 61 provided on the frame 1, so that when the moving magnetic member 41 moves in the motion channel C, it is also restricted by the guide groove 61 and moves linearly;

[0054] (4) Install the second guide assembly 7 on the frame 1, install the guide rail 72 on the frame 1, and allow the slide 71 to move thereon; then fix the welding unit 31 and the slide 71 with a locking piece so that the welding unit 31 can move relative to the frame 1;

[0055] (5) A pressure detection member 51 is installed on the end of the welding unit 31 away from the first electrode A;

[0056] (6) upper limit members 92 are respectively installed at both ends of the spring 9, and the limit members 92 are framed by the hollow frame 91, and then one of the limit members 92 passes through the hollow frame 91 and connects to the pressure detection member 51;

[0057] (7) The other end of the hollow frame 91 is fixedly mounted on the boss 62;

[0058] (8) A distance sensor 8 is installed on the frame 1 and near the original position of the boss 62 to indicate the original point of displacement of the boss 62;

[0059] (9) The light-sensing member 521 and the grating ruler 522 are respectively mounted on the welding member and the side of the frame 1, and the two are arranged opposite to each other;

[0060] (10) A power source D and a signal transmission terminal E are installed on the frame 1, wherein the power source D is used to supply power to the fixed magnetic member 42, the first electrode and the second electrode; the signal transmission terminal E is electrically connected to the pressure sensor and the light sensing member 521 respectively;

[0061] (11) The two electrode connecting blocks F and G are connected to the first and second electrodes A and B respectively to form electrical conduction, thereby completing the assembly of the entire resistance welding device.

[0062] During actual welding:

[0063] (1) The product to be welded is placed on the second electrode B on the fixing seat 2. It can be placed manually or by installing a fixture, as long as the product to be welded is located between the first electrode A and the second electrode B;

[0064] (2) The fixed magnetic member 42 is energized, and its magnetism is changed by the change of the current magnitude and the energization time, so as to drive the moving magnetic member 41 in the moving channel C above it to move along the moving channel C, and slowly move in the direction of the product to be welded, such as 0.1 mm displacement; conversely, when moving in the reverse direction, the phase of the fixed magnetic member 42 is changed;

[0065] (3) When the moving magnetic part 41 moves, the boss 62 on the mounting unit 32 fixed thereto also moves downward (i.e., moves toward the product to be welded), thereby pushing the spring 9 in the frame, the pressure detection part 51 and the welding unit 31 to move downward until they contact the product to be welded. It should be noted that the boss 62 determines the total distance from the original state to the contact with the product through the distance sensor 8 in the original state, and after recording it, controls the boss 62 to be in a fast displacement state when it starts to approach the position of the product to be welded, and changes to a slow speed displacement when it approaches and contacts the product to be welded, until it contacts the product to be welded;

[0066] (4) When the welding unit 31 (first electrode A) contacts the workpiece to be welded, the pressure detection component 51 collects and stores the pressure value, and collects the pressure once every first period T1, for example, once every 1 millisecond T1, to obtain a pressure value P1, P2, P3, P4...; but when the above-mentioned pressure value Pn is in a smooth rising change, it is determined to be the pressure base value Pn. This setting is because the surface of the product to be welded may be uneven, the electrode may be contaminated, and the actual thickness of the product may deviate, resulting in the pressure value being in a fluctuating state of rising and falling, so it is necessary to determine the pressure base value in this way; it should be noted that the smooth rising change refers to the pressure values ​​(Pn-1, Pn-2, Pn-3...) collected by the artificially set number of times (N times) before the pressure value Pn collected this time are all greater than the artificially set value Pm, and / or if the difference between the pressure value Pn collected this time and the moving average pressure value of the artificially set number of times (N times) before is greater than the artificially set value Ph;

[0067] (5) After the artificially set pressure value P0 is added to the pressure base value Pn, the first and second electrodes A and B are energized; for example, P0 (5N force) is added to the determination of Pn, which is the basic pressure for starting welding, and it is determined that the first and second electrodes B are energized for welding;

[0068] (6) After the welding pressure is determined, the displacement value L0 collected by the displacement detection element 52 at the time of obtaining the initial pressure value Pn is calibrated as the base value L0 of the depth of this welding and stored;

[0069] (7) During the welding process, the pressure value P and the displacement value L are collected, stored and compared every first period T1 set manually; during the second period T2, the pressure values ​​Pn+1, Pn+2, Pn+3, Pn+4, etc. obtained in each first period T1 are summarized with the displacement values ​​L1, L2, L3, L4 to generate a real-time envelope curve H1, and the real-time envelope curve H1 is compared with the manually set envelope curve interval H0. It should be noted that the manually set envelope curve H0 can be obtained after manual welding and when the product is qualified after inspection, and the envelope curve interval is formed after the manually set envelope curve H0 is manually offset up and down; in this process, the pressure values ​​P and displacement values ​​L in the first period T1 are obtained and compared to see whether they fall within the manually set envelope curve interval H0. If any pressure value P and / or displacement value L in the real-time envelope curve H1 exceeds the manually set envelope curve interval H0, the weld is determined to be an abnormal weld;

[0070] In this way, not only can the data of the entire welding process be obtained, but the cause of the abnormality can also be checked later, which guarantees the entire welding process and ensures that the welded products are firm and have a long service life.

[0071] The present invention provides a resistance welding device for precision parts welding and a control method for a resistance automatic welding device, which has a simple structure, is easy to manufacture, easy to implement and has low cost, and solves the defects of the resistance welding device in that the movement mode is rigid and inconvenient to use; the present invention adopts a fixed magnetic part and a moving magnetic part arranged in a straight line to cooperate to realize the variable speed movement of the linear motion, and changes the fast movement to a slow displacement when approaching the product to be welded, and can obtain the welding pressure value and the welding displacement value through the detection component, and judge whether the welded product is a qualified part through the pressure value and the displacement value, which is suitable for products with high welding precision requirements and thin parts, and the quality of batch welded products is close, and unqualified welded products can be efficiently selected. The present invention adopts a split welding unit and an attachment unit to form a movable seat, and the two are respectively limited in linear motion by two sets of guide components, so that the movement is faster and more convenient, the overall stability is better, and it is not easy to have deviations during the precision welding process, which is helpful to improve the welding quality; the present invention is also equipped with a spring, through the action of the spring, the pressure detection part can detect the pressure value more accurately, and through the action of the spring, the reaction force when touching the product to be welded is alleviated, and at the same time, the pressure detection part can trigger the detection more quickly; the present invention adopts a grating ruler for detection, which can sense the slight distance changes of precision welding and give more accurate data, It has a good detection effect and provides more accurate data for subsequent welding quality detection. The present invention also provides a limiter and a hollow frame for limiting the movement of the spring, which reduces the distortion of the spring due to the force direction problem and reduces the probability of detection data errors. The control method described in the present invention can achieve fast and uniform quality welding in the process of precision parts welding, and can automatically find the welding position (that is, detect the pressure and depth through the pressure detection part and the displacement detection part), automatically adjust its initial welding pressure, and can automatically adjust the initial pressure when the thickness of the parts to be welded is different and the surface is deformed, breaking the limitations of the traditional welding process, so that the quality of the welded product is better and the connectivity is better.

[0072] The above specification and description of the embodiments are used to explain the protection scope of the present invention, but do not constitute a limitation on the protection scope of the present invention.

Claims

1. A resistance welding device for precision parts welding, characterized in that: The resistance welding device comprises a frame, a fixed seat mounted on the frame, a movable seat, a driving structure and a detection component; A fixing seat, used for carrying the product to be welded and installing the first electrode; A movable seat, which moves relative to the fixed seat through the driving structure, and is equipped with a second electrode and a detection component; the movable seat is arranged in a split body, and includes a welding unit and a mounting unit that cooperate with each other, the mounting unit is connected to the moving magnetic part of the driving structure, and is restricted to move relative to the fixed seat along the frame through the first guide component; the welding unit is driven by the mounting unit and moves relative to the fixed seat by the second guide component; wherein the pressure detection component is installed between the mounting unit and the welding unit; The first guide assembly is used for the attachment unit to move linearly relative to the frame and along the motion channel; the first guide assembly includes a guide groove and a boss, the guide groove is opened on the frame and the boss passes through; the boss is formed on the attachment unit; wherein the attachment unit moves through the cooperation of the moving magnetic part and the fixed magnetic part, and the boss and the guide groove limit the linear displacement, so that the boss presses the spring, the pressure detection part, and the welding unit to move toward the fixed seat; The second guide assembly includes a slide and a guide rail; the guide rail is mounted on the frame and allows the slide to move thereon; the slide is fixed to the welding unit; wherein the slide slides along the guide rail to limit the linear movement of the welding unit relative to the fixed seat; The driving structure includes a plurality of fixed magnetic parts and moving magnetic parts, each of which is laid on the frame at intervals along the trajectory of the moving seat, and forms a moving channel; the moving magnetic part falls on the moving channel for displacement, and is mounted on the moving seat; A detection component is used to detect welding pressure and welding depth; the detection component includes a pressure detection component and a displacement detection component respectively mounted on a movable seat; the pressure detection component is used to detect the force exerted by the second electrode on the movable component on the object to be welded; the displacement detection component is used to detect the displacement of the second electrode during welding.

2. A resistance welding device for precision parts welding as claimed in claim 1, characterized in that: The movable seat also includes a spring, one end of which abuts against the mounting unit and the other end acts on the pressure detection member.

3. A resistance welding device for precision parts welding as claimed in claim 1 or 2, characterized in that: The displacement detection component includes a photosensitive component and a grating ruler. The photosensitive component is installed on the side of the welding unit; the grating ruler is fixed to the frame and is arranged opposite to the photosensitive component.

4. A resistance welding device for precision parts welding as claimed in claim 3, characterized in that: It also includes a hollow frame and two limiters for limiting the distortion of the spring, wherein the hollow frame is fixedly connected to the boss; the two limiters are respectively installed in the hollow frame and are sleeved at both ends of the spring; wherein the limiter at one end away from the boss is connected to the pressure detection component.

5. A welding method of a resistance automatic welding device as claimed in any one of claims 1 to 4, characterized in that: By changing the power-on time or current size of the fixed magnetic part, the moving magnetic part is controlled to move at a variable speed in the linear motion channel formed between the fixed magnetic parts, and slowly moves when the second electrode approaches the workpiece to be welded; When the second electrode of the pressure detection component contacts the workpiece to be welded, the pressure value is collected and stored, and if the pressure values ​​collected for the artificially set number of times before the pressure value collected this time are all smoothly rising, then the pressure value collected this time is determined to be the pressure base value; and the displacement value collected by the displacement detection component at the time of obtaining the initial pressure value is calibrated as the base value of the depth of this welding and stored; After the artificially set pressure value is added to the pressure base value, the first and second electrodes are energized for welding; During welding, the pressure value and the displacement value are collected, stored and compared every manually set first period; in the second period, the pressure values ​​and displacement values ​​obtained in each first period are summarized to generate a real-time envelope curve, and the real-time envelope curve is compared with the manually set envelope curve interval. If any pressure value and / or displacement value in the real-time envelope curve exceeds the manually set envelope curve interval, the weld is determined to be an abnormal weld.

6. The control method of the resistance automatic welding device according to claim 5, characterized in that: The smooth rising change is configured to determine that the first and second electrodes are energized and welded if the pressure value collected the previous manually set number of times of the pressure value collected this time is greater than the manually set value, or if the difference between the pressure value collected this time and the moving average pressure value of the previous manually set number of times is greater than the manually set value.

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