Laser welding method and compressor

Abstract

A laser welding method, comprising the following steps: setting a laser beam trajectory, and the movement speed of a first weld part and a second weld part, wherein the laser beam trajectory comprises an oscillation trajectory and an oscillation frequency; arranging the first weld part and the second weld part, wherein there are at least two intersection points between the oscillation trajectory and a gap to be welded that is between the first weld part and the second weld part; and moving the first weld part and the second weld part at the movement speed, and activating a laser beam to weld the first weld part and the second weld part along the laser beam trajectory. The method can weld larger gaps by means of at least two intersections between the laser beam oscillation trajectory and the gap to be welded, thereby reducing the arrangement precision between parts to be welded, and also enhancing the effective sealing depth of a weld and improving welding sealing performance. The present invention further relates to a compressor.

Description

Laser welding method and compressor TECHNICAL FIELD

[0001] The present application relates to the field of electrical connection, in particular, to a laser welding method and a compressor. BACKGROUND

[0002] The fixing connection between the upper cover (or lower cover) of the air conditioner compressor and the shell is usually achieved by using the Metal Active Gas Arc Welding (MAG welding) process. The MAG welding uses mixed gas as a protective agent and electrode material as a filler material for welding. The disadvantages of this process are as follows: 1. The welding deformation is large, which affects the product precision; 2. The discharge electric corrosion between the precise components of the compressor caused by the conduction of the compressor during welding leads to the decline of product precision; 3. The welding spatter is large, and the spatter needs to be removed after welding; 4. The direct material cost is brought by the use of welding material during welding.

[0003] In order to improve the above-mentioned problems of MAG welding, and considering that the investment in welding wire will increase the manufacturing cost, some compressor components use laser welding method which does not need filler material. However, the laser welding method has the following problems:

[0004] 1. The laser welding is not suitable for the existing welding groove. In the welding field, different welding types need to be designed with corresponding welding grooves. The existing MAG welding corresponds to a V-shaped welding groove, which is a typical welding groove structure designed for filler welding method, which is beneficial to filling the V-shaped groove with welding material to form a high-quality weld during welding. However, laser welding belongs to self-dissolving welding, and there is no welding material filling during welding, so the V-shaped groove is not needed at the welding position. Usually, the V-shaped groove is mainly arranged on the inner chamfer of the shell, and the chamfer also plays a guiding role. If the groove is cancelled, the above-mentioned guiding role will be lost, which will cause damage during installation. It is a technical challenge to apply laser self-dissolving welding to the V-shaped groove.

[0005] 2. The product fitting gap affects the quality of laser welding. The shell cover and the shell of the compressor are both circular or both have an arc, and after being installed together, there is an installation gap. During laser welding, the laser beam will directly pass through the gap, causing incomplete welding or insufficient penetration;

[0006] 3. The welding position deviation affects the quality of laser welding. Due to the influence of the arc of the shell cover and the shell, during the circumferential welding, the welding position deviates, causing virtual welding or incomplete welding.

[0007] 4. Laser welding requires higher material cleanliness. In mass production, oil stains and other poor cleanliness conditions may occur on the material. Since the energy density of laser welding is higher than that of MAG welding, high-density heating is more likely to produce welding pores, and severe ones may produce burst holes, causing compressor leakage, affecting the yield of welding, and rework will also cause a decrease in production efficiency.

[0008] Therefore, how to improve the quality of laser welding is a problem to be solved by the present application.

[0009] It should be noted that the information disclosed in the above background section is only used to strengthen the understanding of the background of the present application, and therefore can include information that does not constitute prior art known to those skilled in the art. SUMMARY

[0010] In view of the problems in the prior art, the purpose of the present application is to provide a laser welding method and a compressor, which can weld a larger gap by at least two intersections of the laser beam swing trajectory and the gap to be welded, thereby reducing the arrangement accuracy between the parts to be welded, and at the same time, improving the effective sealing depth of the weld and the welding sealing performance.

[0011] The first aspect of the present application provides a laser welding method, the welding method comprising the following steps:

[0012] S100: setting a laser beam trajectory and a moving speed of a first welding part and a second welding part, the laser beam trajectory comprising a swing trajectory and a swing frequency;

[0013] S200: arranging the first welding part and the second welding part, the swing trajectory having at least two intersection points with a gap to be welded between the first welding part and the second welding part;

[0014] S300: moving the first welding part and the second welding part at the moving speed, and starting a laser beam to weld the first welding part and the second welding part at the laser beam trajectory.

[0015] According to the first aspect of the present application, the swing trajectory is a combination of one or more of a polygon, a circle and an ellipse.

[0016] According to the first aspect of the present application, the swing trajectory is symmetrical with respect to the gap to be welded.

[0017] According to the first aspect of the present application, the swing trajectory is a quadrilateral;

[0018] The spot diameter of the laser beam is D;

[0019] The quadrilateral has a first side length H along a direction perpendicular to an extension direction of the gap to be welded.

[0020] The gap to be welded between the first welding member and the second welding member has a width h, and the following condition is satisfied: D+h / 2≤H≤D+h.

[0021] According to the first aspect of the present application, the quadrilateral has a second side length L along the extension direction of the gap to be welded, and the following condition is satisfied: D

[0022] The quadrilateral has a second side length L along the extension direction of the gap to be welded, and the following condition is satisfied: H

[0023] According to the first aspect of the present application, the swing frequency is ≤100 Hz.

[0024] According to the first aspect of the present application, the gap to be welded between the first welding member and the second welding member has a width h, and the width h is less than or equal to 1.0 mm.

[0025] According to the first aspect of the present application, the swing trajectory is achieved by swing of a galvanometer inside the laser welding head.

[0026] The second aspect of the present application provides a compressor, at least two components of which are fixedly connected by the laser welding method.

[0027] According to the second aspect of the present application, the compressor comprises an upper shell cover, a lower shell cover and a shell body.

[0028] The upper shell cover and the shell body, and the lower shell cover and the shell body are fixedly connected by the laser welding method.

[0029] The laser welding method of the present application reduces the direct material cost of welding wire by at least twice intersection of the swing trajectory of the laser beam and the gap to be welded, repairs the defects of pre-welding at the first intersection, and enhances the ability of molten pool stirring at the second intersection, thereby excluding pores in the molten pool, enhancing the ability of melting base material, and filling and covering the height of the current. Accordingly, the laser welding method of the present application can weld a larger gap, thereby reducing the arrangement accuracy between the welding members to be welded, and improving the effective sealing depth of the weld and the welding sealing performance. BRIEF DESCRIPTION OF DRAWINGS

[0030] Other features, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments, made with reference to the accompanying drawings.

[0031] Fig. 1 is a flowchart of the laser welding method according to an embodiment of the present application.

[0032] FIG. 2 is a plan view of the laser welding method of one embodiment of the present application during welding;

[0033] FIG. 3 is a cross-sectional view of the laser welding method of one embodiment of the present application during welding; and

[0034] FIGS. 4 to 7 are schematic views of the laser welding method of one embodiment of the present application during welding of a shell cover and a shell of a compressor. DETAILED DESCRIPTION

[0035] Example embodiments now will be described more fully hereinafter with reference to the accompanying drawings. Example embodiments, may, however, be implemented in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. Embodiments described below are examples only, and are not intended to be limiting. Like reference numerals in the drawings designate like elements, and thus their repeated description will be omitted.

[0036] In the description of the present application, it is to be understood that the terms "first", "second", "third" and the like, do not connote any hierarchy or order, but are simply used to distinguish one element from another. In addition, the terms "comprise", "comprising", "include", "including", "have", "has", "contain", "containing", or any other similar term are intended to be inclusive or open-ended and do not exclude additional, unrecited elements or methods. Thus, such terms in the description of the present application are not intended to be limiting.

[0037] In the description of the present application, it is to be understood that the terms "mounting", "connected", "connecting", "connection" should be construed broadly according to the context in which they are used, for example, they can be fixed connection, or detachable connection, or integrally connected; can be mechanical connection, or electrical connection or can communicate with each other; can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0038] The following disclosure provides many different embodiments, or examples, for implementing different structures of the present application. For the purpose of simplification, the components and arrangements of the specific examples are described in the following. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeatedly refer to the same reference numerals and / or reference letters in different examples, and such repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or arrangements discussed. In addition, the present application provides examples of various specific processes and materials, but those skilled in the art can realize the application of other processes and / or the use of other materials.

[0039] In order to solve the technical problems in the prior art, the present application provides a laser welding method and a compressor, the welding method comprising the following steps: setting a laser beam trajectory and a moving speed of a first welding piece and a second welding piece, the laser beam trajectory comprising a swing trajectory and a swing frequency; arranging the first welding piece and the second welding piece, the swing trajectory having at least two intersection points with a gap to be welded between the first welding piece and the second welding piece; moving the first welding piece and the second welding piece at the moving speed, and starting a laser beam to weld the first welding piece and the second welding piece at the laser beam trajectory.

[0040] The laser welding method of the present application reduces the direct material cost of welding wire and improves the welding quality through at least two intersections of the laser beam swing trajectory and the gap to be welded, pre-welding at the first intersection and repairing the pre-welding defects at the second intersection. Further, the two laser beam trajectories in the swing trajectory along the extension direction of the gap to be welded can stir the molten pool to eliminate pores in the molten pool, and enhance the ability of melting base material, converging and filling the stack height. Accordingly, the laser welding method of the present application can weld a larger gap, thereby reducing the arrangement accuracy between the pieces to be welded, while improving the effective sealing depth of the weld and enhancing the welding sealing performance.

[0041] The laser welding method and the compressor of the present application will be further described below in combination with the accompanying drawings and specific embodiments, and it can be understood that each specific embodiment is not a limitation on the protection scope of the present application.

[0042] FIG. 1 is a flowchart of the laser welding method of an embodiment of the present application, specifically, the laser welding method comprising the following steps:

[0043] S100: set the laser beam trajectory and the moving speed of the first welding piece and the second welding piece, the swing trajectory is the path of the laser beam swing, the invention adopts swing laser welding (dynamic laser welding), that is, the laser welding head of the laser welding equipment is a swing head. The swing of the laser beam is realized by setting two high-speed turning mirrors in the laser welding head, and the moving direction and trajectory of the laser beam can be changed by the high-speed swing of the mirrors. The laser beam trajectory includes the swing trajectory and the swing frequency, the swing trajectory is the minimum cycle of the laser beam in the swing laser welding, and the swing trajectory can be polygonal, circular or elliptical, or a combination of multiple polygons, circles and ellipses, such as 8-shaped, ∞-shaped, spiral-shaped, etc. Special patterns can be achieved by programming the swing of the mirror in the laser welding head. The laser welding equipment is usually configured with setting software, and the laser swing welding function is selected during welding, and the swing trajectory parameters of the laser beam are set, such as the diameter of the swing trajectory when the swing trajectory is circular, the length and width of the swing trajectory when the swing trajectory is rectangular, etc. Details are not repeated here.

[0044] S200: arrange the first welding piece and the second welding piece, and the swing trajectory has at least two intersection points with the gap to be welded between the first welding piece and the second welding piece. Of course, before arrangement, the welding parts of the first welding piece and the second welding piece can be polished, pickled or laser cleaned for welding pretreatment process. Here, the arrangement is the initial position of the first welding piece and the second welding piece, and the first welding piece and the second welding piece will move during welding, and more precisely, the gap to be welded between the two will move as a whole, and the actual welding trajectory is the coupling of the laser beam trajectory and the moving trajectory of the first welding piece and the second welding piece.

[0045] Fig. 2 and Fig. 3 are respectively the top view and sectional view of the laser welding method of an embodiment of the present application during welding, wherein the swing trajectory is a quadrilateral, the first side length of the quadrilateral is H perpendicular to the extension direction of the gap to be welded, and the second side length of the quadrilateral is L along the extension direction of the gap to be welded. Preferably, the quadrilateral is a rectangle, then L is the long side of the rectangle and H is the short side of the rectangle. The first welding piece and the second welding piece are arranged below the laser welding head, and the position of the gap to be welded is preset in the quadrilateral swing area, and the swing trajectory is symmetrical relative to the gap to be welded, that is, the gap to be welded is on the central axis of the short side H of the quadrilateral. In actual use, the front vision guide of the laser equipment can be used to ensure that the gap to be welded is always between the two long sides of the rectangular swing trajectory during welding. If the gap to be welded deviates to any one of the long sides of the quadrilateral or beyond, the other long side will be invalid for welding, which will reduce the ability of the melted base material to flow and cover during welding, thereby reducing the welding quality.

[0046] In the above embodiment, when welding, the gap between the materials to be welded can be rotated clockwise, as shown by the dashed arrow in FIG. 2, and the laser welding head is stationary. The laser welding head obtains a set laser beam swing trajectory under the action of the high-speed movement of the high-speed rotating galvanometer in the laser welding head. The laser beam starts at point A1 and swings along the quadrilateral trajectory. The gap between the first welding piece and the second welding piece moves clockwise relative to the laser beam trajectory. After passing point A2, it returns to point A1. This is one quadrilateral light emitting period. The swing frequency in step S200 is the number of times the swing trajectory is completed in one second. For example, if the swing frequency is 100 Hz, the laser beam can complete 100 quadrilateral swing trajectories in one second.

[0047] After performing step S200, step S300 is performed: moving the first welding piece and the second welding piece at the moving speed, and starting the laser beam to weld the first welding piece and the second welding piece along the laser beam trajectory. The laser device used in the present application can be a single-mode laser or a multi-mode laser. The power of the laser can be 500 W or more, and an optical fiber with a core diameter of 50 μm or more can be used. The swing line speed can be 2000 mm / s or more. The protective gas during welding can be nitrogen or argon, and the gas flow rate can be 2.0 L / min or more.

[0048] During the welding process of step S300, when the laser beam passes through point A1, it is the first welding. From point A1 on one side of the gap to be welded to point A2, and from point A2 on the other side of the gap to be welded to point A1, the base materials on both sides of the gap to be welded are melted, merged, and filled to form a weld, which improves the effective sealing depth of the weld and enhances the sealing performance of the weld. Finally, when passing through point A2, the weld is shaped to obtain a high-quality weld. When the gap to be welded has defects, such as encountering poor material cleanliness, oil stains, and other situations that produce blowholes, weld collapse, and porosity, the base materials of the two long sides L of the quadrilateral are melted when the laser beam passes through A1-A2, and the weld defects are repaired and filled, and the existing weld is stacked. Finally, when passing through point A2, 2 welds are performed to repair the weld defects and complete the self-healing welding mechanism.

[0049] In the welding method of the present application, the first intersection point of the swing trajectory and the gap to be welded is A1, and the second intersection point is A2. The moving speed of the first welding member and the second welding member can be designed, that is, the moving speed of the gap to be welded needs to be at least less than 1 / 2 of the speed of the laser beam along the long side of the swing trajectory, so that the second intersection point A2 and the first intersection point A1 at least partially overlap. At this time, the two long sides of the rectangle melt the base material of the shell and the shell cover, respectively, and the molten material fills the gap. At the same time, due to the movement of the gap to be welded, when the swing trajectory passes through the gap to be welded twice, it welds the same part of the gap to be welded. The first welding can be regarded as pre-welding, which plays a role in cleaning the welding point. The second welding can be regarded as repairing defects at the pre-welding point. Through twice welding at a position of the gap to be welded, the welding quality can be improved, such as improving the effective sealing depth and sealing performance of the weld. In addition, for special materials, such as materials prone to porosity and cracking, the swing of the laser beam in the welding method of the present application plays a "stirring role", which can improve the grain size of the weld area and eliminate welding defects such as porosity and cracking. When welding with a circular swing trajectory, the repeated welding area is large, and the laser beam has multiple heating effects on the molten pool, which can help the pores in the molten pool overflow and refine the grain size of the weld. The grain size of the weld obtained by the welding method of the present application can be between 0.05 mm and 0.2 mm. The grain size of the weld obtained by the existing laser welding method (without swing welding) is generally greater than 0.2 mm.

[0050] In order to further improve the welding effect, in the welding method of the present application, the spot diameter of the laser beam is D, and the width of the gap to be welded between the first welding member and the second welding member is h. One or more of the following conditions are met: D < L; D + h / 2 ≤ H ≤ D + h; H < L.

[0051] In practice, the welding gun distance can be confirmed according to the standard focal length value of the laser welding head, and the spot diameter D of the laser beam under the gun distance can be confirmed. In the above conditions, increasing H, that is, increasing the swing area, can improve the repair ability during the second welding, thereby improving the welding quality. Taking the rectangular swing trajectory as an example, when the gap to be welded passes through the short side of the rectangle at high temperature for the first time, if welding defects occur, due to the large swing area, the blast hole position has more opportunities to repair the defects when passing through the large rectangular swing area. During the repair process, when the laser beam moves along the long side of the rectangle to weld, the base material is melted to cover the welding defect position, so that welding repair is performed when the gap to be welded passes through the short side perpendicular to the extension direction.

[0052] The present application also provides a compressor, at least two components of which are fixedly connected by the laser welding method. More specifically, the compressor comprises an upper shell cover, a lower shell cover and a shell body, and the laser welding method is used to fixedly connect the upper shell cover and the shell body and the lower shell cover and the shell body. FIGS. 4-7 are schematic diagrams of different stages of welding the shell cover and the shell body of the compressor by the laser welding method according to an embodiment of the present application, wherein the shell cover is either an upper shell cover or a lower shell cover. During welding, the laser beam irradiates an arbitrary point X on the gap to be welded, and the laser beam irradiates points A1 and A2 on the swing trajectory in sequence, and the arbitrary point X receives the first welding at the position point A1 and receives the second welding at the position point A2. The dynamic laser needs to complete irradiation and heating of each of the two long sides of the quadrilateral not less than 1 time, and if the irradiation is more than 1 time, the irradiation interval time needs to be greater than or equal to 0.01 s, wherein 0.01 s is the weld cooling time, and the two long sides of the rectangle are repeatedly heated in the solid state. Repeated solid-state heating is more beneficial to filling the gap to be welded and substantially completing the weld overlap, and produces a zipper effect. In order to ensure the production of the zipper welding effect, the speed of the dynamic laser beam cannot be too slow or too fast, and preferably, the swing frequency in the S200 step is less than or equal to 100 Hz. Based on the heating of the long sides of the rectangle in the solid state, the arbitrary point X is in the solid state when passing through the A2 point, and only in the solid state can the second welding repair effect be produced, as shown in FIG. 7.

[0053] When the swing trajectory is of other shapes, the welding process is as described above, but the spot diameter of the laser beam, the moving speed of the first welding piece and the second welding piece, the swing frequency and other welding parameters can be set to different values. For example, the irradiation and heating range of the laser beam can be increased by increasing the spot diameter of the laser beam. When the gap to be welded is large, the swing range of the swing trajectory can be increased, which in the above example is to increase the length of the first side H. Since the laser welding method of the present application is actually twice welding, and the laser beam stirs the melted base material, converges and fills the weld, the width of the weldable gap can be effectively increased. Compared with the existing laser welding, the maximum gap to be welded is about 0.3 mm, and the width h of the gap to be welded by the welding method of the present application can reach 1.0 mm. Therefore, the welding method is suitable for a gap to be welded with a width less than or equal to 1.0 mm, and can effectively reduce the precision of arranging the workpiece to be welded. At the same time, since the precision requirement of the above-mentioned gap to be welded is reduced, in some embodiments, the laser equipment does not need to be matched with a front vision guiding system, and the dynamic laser zipper welding of the present application can directly meet the welding requirements.

[0054] The welding of the compressor shell cover and the shell is circumferential welding, and the movement of the welding gap to be welded is rotation. The welding method can also be applied to the welding of curved surface welds, straight welds, or irregular shapes composed of the same, and the movement of the welding gap to be welded or the workpiece to be welded is slightly different.

[0055] Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the present application, and those of ordinary skill in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

[0056] The above is a further detailed description of the present application in combination with specific preferred embodiments, and it cannot be considered that the specific implementation of the present application is limited to these descriptions. For those of ordinary skill in the art to which the present application belongs, without departing from the concept of the present application, a number of simple deductions or replacements can also be made, which should be considered as falling within the scope of protection of the present application.

Claims

1. A laser welding method characterized by, The welding method comprises the following steps: S100: setting a laser beam track and a moving speed of a first welding piece and a second welding piece, the laser beam track comprising a swing track and a swing frequency; S200: arranging the first welding piece and the second welding piece, the swing track having at least two intersection points with a gap to be welded between the first welding piece and the second welding piece; S300: moving the first welding piece and the second welding piece at the moving speed, and starting a laser beam to weld the first welding piece and the second welding piece at the laser beam track.

2. The laser welding method according to claim 1, characterized in that, The swing track is a combination of one or more of a polygon, a circle and an ellipse.

3. The laser welding method according to claim 1, characterized in that, The swing track is symmetrical relative to the gap to be welded.

4. The laser welding method according to claim 1, characterized by, The swing track is a quadrilateral. The spot diameter of the laser beam is D; The first side length of the quadrilateral in a direction perpendicular to the extension direction of the gap to be welded is H; The width of the gap to be welded between the first welding piece and the second welding piece is h, and the following condition is satisfied: D+h / 2≤H≤D+h.

5. The laser welding method according to claim 4, characterized in that, The second side length of the quadrilateral in the extension direction of the gap to be welded is L, and the following condition is satisfied: D<L; or 6. The laser welding method according to claim 1, characterized by, The second side length of the quadrilateral in the extension direction of the gap to be welded is L, and the following condition is satisfied:

7. The laser welding method of claim 1, wherein, H<L.

8. The laser welding method of claim 1, wherein, The swing frequency is ≤100Hz.

9. A compressor characterized by, The width of the gap to be welded between the first welding piece and the second welding piece is h, and the width h is less than or equal to 1.0mm.

10. The compressor of claim 9, wherein, The swing track is realized by swing of a galvanometer inside a laser welding head. The laser welding method of any one of claims 1 to 8 is used to fixedly connect at least two components of the compressor. The compressor comprises an upper shell cover, a lower shell cover and a shell body; The laser welding method is used to fixedly connect the upper shell cover and the shell body, and the lower shell cover and the shell body.

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