CN116197516A - Friction stir welding device - Google Patents

Abstract

The present invention provides a friction stir welding apparatus, comprising: a frame body; a pivot module, connect in this support body, include: an inner rotating shaft; and an outer rotating shaft sleeved outside the inner rotating shaft; a welding tool fixedly connected to the inner rotating shaft; the pressing block is sleeved on the outer side of the welding tool and fixedly connected with the outer rotating shaft; when the welding tool performs friction stir welding on the two workpieces to be welded, the pressing block rotates and presses the two workpieces to be welded relatively, and the force of the pressing block for pressing the two workpieces to be welded is smaller than the force of the welding tool for pressing the two workpieces to be welded. Therefore, the aims of pressing and fixing the workpiece to be welded, reducing the buckling deformation of the welding part along the welding bead, removing burrs, leveling the welding bead synchronously and the like are fulfilled.

Description

Friction stir welding device

Technical Field

The present invention relates to a friction stir welding apparatus, and more particularly to a friction stir welding apparatus capable of providing pressing and leveling of a work piece to be welded.

Background

Friction stir welding is a solid state welding method, which uses friction stirring tools to rub with workpieces to be welded under high-speed rotation to generate heat so as to soften materials at the positions to be welded to form welding beads, and the welding beads have mechanical properties superior to those of the traditional arc welding, have low energy consumption, do not generate smoke dust and arc light in the welding process, and are regarded as green and environment-friendly technology.

When friction stir welding is performed on thin plates (e.g., plates having a thickness of less than 3 mm), the rigidity of the workpiece to be welded is limited, and the workpiece to be welded needs to be properly held and the closer to the welding point is. However, when the workpiece to be welded is a thin plate member having a large area, the pressing of the workpiece to be welded can be a difficult problem in the welding practice. The current common practice is to clamp large-area workpieces to be welded by using large-scale special jigs. In addition, the welding of the thin plate has the problem of deformation, and the deformation of the welding of the thin plate with a large area is more difficult to predict and inhibit, so that the welding cannot meet the product precision requirement. In the welding process, the friction stirring tool provides a quite large downward extrusion force for the workpiece to be welded, so that the welding bead periphery deformation and the burr problem are more easily caused for the thin plate, and the appearance of the product is influenced.

The following patent documents each propose solutions to the above-mentioned problems of sheet welding:

chinese patent No. CN 102672345A discloses a friction stir welding tool and a welding method thereof, which is suitable for welding thin plates, the welding tool comprises a stirring head, a radial positioning bearing, a pressing sliding block and a fixed frame, the radial positioning bearing is sleeved on the outer side wall of the stirring head, the pressing sliding block is fixedly installed on the lower surface of the fixed frame, the pressing sliding block and the fixed frame are integrally sleeved on the outer side wall of the stirring head, the radial positioning bearing is positioned between the outer side wall of the stirring head and the inner side wall of the fixed frame, and the shaft shoulder and the stirring pin of the stirring head are exposed out of the lower surface of the pressing sliding block. In the welding process, the pressing sliding block presses the welded workpiece along with welding, so that the workpiece is prevented from buckling deformation.

Chinese patent No. CN 104722910A discloses a friction stir connector capable of reducing deformation and removing burrs, which comprises a stirring shaft, a bearing block, a roller holder, rollers and a sleeve. The stirring shaft is fixedly connected with the bearing block, the bearing block and the sleeve are connected through the roller retainer and the roller to rotate relatively, and a gap is reserved between the sleeve and the stirring shaft, so that the sleeve does not rotate along with the stirring shaft in the working process. When welding, the stirring shaft is driven by the main shaft to rotate and press downwards, the pressure bearing blocks synchronously rotate, and the downward pressure of the stirring shaft is transmitted to the sleeve to press the workpiece, so that the workpiece is fixed. And when the stirring shaft moves along the welding direction, the softened burrs can be removed from the bottom end of the sleeve, which is in contact with the workpiece.

Chinese patent No. CN 209830594U discloses a double-end friction stir welding device, in which a friction stir head acts on a portion to be welded to form a weld, and a spinning head is located behind the friction stir head at a certain distance to spin the weld and the metal in the near-seam region. The weld and near-seam zone metal may also be spun extruded after the welding process is completed. The welding seam generates longitudinal plastic expansion, and the longitudinal residual tensile stress of the welding seam and the adjacent area is reduced, so that the residual deformation of the sheet welding piece is reduced.

Although the technical solutions of the foregoing documents are proposed to solve the problems derived from welding thin plates, there are a number of drawbacks and inconveniences. How to provide a friction stir welding solution to the above-mentioned problem of welding the thin plate has become one of the concerns of those skilled in the art.

Disclosure of Invention

The invention aims to provide a friction stir welding device which can press and fix a workpiece to be welded, reduce the buckling deformation of the welded part along a welding path, remove burrs and level the welding path synchronously.

It is a further object of the present invention to provide a friction stir welding apparatus that counteracts at least a portion of the torque applied to the workpiece to be welded by the welding tool.

It is still another object of the present invention to provide a friction stir welding apparatus that reduces residual stresses created by welding.

In accordance with the above object, the present invention provides a friction stir welding apparatus comprising: a frame body; a pivot module, connect in this support body, include: an inner rotating shaft; and an outer rotating shaft sleeved outside the inner rotating shaft; a welding tool fixedly connected to the inner rotating shaft; the pressing block is sleeved on the outer side of the welding tool and fixedly connected with the outer rotating shaft; when the welding tool performs friction stir welding on the two workpieces to be welded, the pressing block rotates and presses the two workpieces to be welded relatively, and the force of the pressing block for pressing the two workpieces to be welded is smaller than the force of the welding tool for pressing the two workpieces to be welded.

The friction stir welding device is characterized in that a pressing block is sleeved outside a welding tool, and the pressing block moves and rotates along with the welding tool in the welding process, so that the workpiece to be welded is pressed and fixed, the thinner welding part can be reduced from buckling deformation along a welding path, the welding path can be flattened synchronously, and burrs formed by welding are removed. When the pressing block and the welding tool turn reversely, the friction force of the pressing block can offset at least one part of torsion force applied to the workpiece to be welded by the welding tool, and the residual stress formed by welding can be reduced. The outer edge of the propping surface of the pressing block is embedded with a blade, so that the welding bead and the periphery thereof can be trimmed, and a welding piece with high appearance quality is obtained.

Drawings

FIG. 1 is a schematic view of a friction stir welding apparatus according to an embodiment of the present invention.

Fig. 2 is a schematic diagram of welding according to an embodiment of the present invention.

Fig. 3 is a top cross-sectional view of a weld made in accordance with an embodiment of the present invention.

Fig. 4 is a cross-sectional view of a monolith of the trimmable bead of the present invention.

Fig. 5 is a cross-sectional view of a press block of the present invention providing rolling contact.

FIG. 6 is a cross-sectional view of a pressure-adjustable compression block of the present invention.

In the figure:

friction stir welding device

10, frame body

20 spindle module

21 inner rotating shaft

22 outer rotary shaft

30 welding tool

31 handle portion

32 stirring pin

33 shoulder portion

40, 40', 40' ', 40' '': compacting blocks

41, 41' ' ': one end

42, 42', 42' ', 42' '': the other end

421, 421', 421 ", 421'" against a surface

43 blade

44 ball bearing

45 upper block

451 perforations

452 guide groove

46 lower block

461 perforation

462 guide pin

47 elastic member

50-degree pressing jig

51 pressing portion

511 roller

60 heating plate

110, 120 to-be-welded workpiece

130 welding bead

200, a traveling module.

Detailed Description

In order to make the above and other objects, features and characteristics of the present invention more comprehensible, embodiments accompanied with drawings are described in detail below, wherein the drawings are mainly simplified schematic illustrations, and only basic structures of the present invention are schematically illustrated, so that only elements related to the present invention are labeled in the drawings, and the elements are not drawn in the number, size ratio, etc. of the embodiments, and the layout of the elements may be more complicated.

The terms "upper", "lower", "front", "rear", "left", "right", "inner", "outer", "side", etc. used in the present description refer only to the directions of the drawings. The directional terminology is used for purposes of illustration and understanding only and is not intended to be limiting of the invention.

Fig. 1 is a schematic structural view of an embodiment of a friction stir welding apparatus according to the present invention, fig. 2 is a schematic structural view of welding performed by the embodiment of the friction stir welding apparatus according to the present invention, and fig. 3 is a cross-sectional plan view of welding performed by the embodiment of the friction stir welding apparatus according to the present invention. Referring to fig. 1 to 3, a friction stir welding apparatus 1 according to the present embodiment includes: a frame 10, a spindle module 20, a bonding tool 30, and a press block 40.

The rotating shaft module 20 is fixedly connected to the frame 10, and includes: an inner shaft 21 rotatable relative to the frame 10 for driving the welding tool 30 to rotate for performing a welding operation; and an outer rotating shaft 22 sleeved on the outer side of the inner rotating shaft 21 and capable of rotating relative to the frame 10. The inner shaft 21 and the outer shaft 22 can be driven by the same power source (not shown), and the rotation ratio and rotation direction of the two shafts can be set by a gear set (not shown). The inner shaft 21 and the outer shaft 22 can be driven by a power source.

The bonding tool 30 has a shank 31, a pin 32, and a shoulder 33. The shank 31 is fixedly connected to the inner shaft 21 and rotates therewith. The stirring pin 32 is used for friction stirring the two workpieces 110, 120 under high-speed rotation, and the two workpieces 110, 120 are softened by heat energy generated by friction to form a welding bead 130.

The pressing block 40 is sleeved outside the welding tool 30 and fixedly connected to the outer rotating shaft 22 to be driven to rotate by the welding tool. When the welding tool 30 welds the two workpieces 110, 120 to be welded, the pressing block 40 rotates while simultaneously pressing and fixing the two workpieces 110, 120 to be welded, the welding area just stirred by the welding tool 30 is still in a plastic flow state, the continuous pressing of the pressing block 40 can reduce the buckling deformation (angular deformation) of the thinner workpieces 110, 120 to be welded along the welding bead, and the rotating pressing block 40 can touch burrs formed by welding at a higher speed to cut off the burrs and simultaneously level the welding bead 130.

The press block 40 shown in fig. 1 has one end 41 connected to the outer shaft 22 and the other end 42 having a pressing surface 421 for pressing the two workpieces 110, 120 to be welded and leveling the weld bead 130. In the welding process, the pressing block 40 is pressed against the surfaces of the two workpieces 110, 120 to be welded and rotated, and heat is generated by friction, so that the pressing block 40 needs to have high temperature strength, hardness and wear resistance, and the material of the pressing block is selected from tool steel, preferably hot work tool steel, and is subjected to heat treatment to obtain the required mechanical properties.

Referring to fig. 3, the outer diameter of the propping surface 421 should be larger than the width of the welding bead 130 to provide enough holding area and holding force for the two workpieces 110 and 120 to be welded, so as to avoid buckling deformation during welding of the two thinner workpieces 110 and 120 to be welded and to provide leveling effect for the welding bead 130. In one application, the outer diameter of the propping surface 421 is 3 times or more the diameter of the stirring pin 32 of the welding tool 30 and 7 times or less the diameter of the stirring pin 32.

The rotational speed of the pressing block 40 (i.e., the rotational speed of the outer rotary shaft 22) is preferably 300 rpm or more and 2000 rpm or less. Whereby the block 40 can strike the burrs at a high speed to cut them off and simultaneously planarize the weld bead 130. The direction of rotation of the lamination block 40 may be the same or opposite to the direction of rotation of the bonding tool 30.

During the welding process, the pressing surface 421 of the pressing block 40 is pressed against the surfaces of the two workpieces 110, 120 to be welded and rotated, and the pressing and rotating generates friction force to provide a torque to the workpieces 110, 120 to be welded. The torque applied to the workpieces 110, 120 as the compact 40 rotates when the compact 40 is turned opposite to the welding tool 30 may cancel at least a portion of the torque applied by the welding tool 30 to the workpieces 110, 120. The amount of torque provided by the press block 40 to the workpieces 110, 120 to be welded may be calculated from the force with which the press block 40 presses against the workpieces 110, 120 to be welded, the coefficient of friction between the press block 40 and the workpieces 110, 120 to be welded, the internal and external diameter dimensions of the press block 40, and other operating parameters. Therefore, by selecting the above-mentioned operation parameters, the majority of the torque applied to the workpieces 110, 120 by the welding tool 30 can be offset, so that the use of large, complex and special clamping tools can be reduced, and the tool cost can be reduced. For example, when the size and material of the press block 40 and the material of the workpieces 110, 120 to be welded are known, the operator can cancel out most of the torque applied to the workpieces 110, 120 by the welding tool 30 by selecting the force with which the press block 40 presses against the workpieces 110, 120 to be welded.

Friction stir welding causes a severe flow (plastic deformation) of the material at the weld and thus tends to cause stress residues at the weld. When the rotation direction of the pressing block 40 is opposite to the rotation direction of the welding tool 30, the direction of the stress applied to the workpieces 110, 120 to be welded by the pressing block 40 is opposite to the direction applied by the welding tool 30, which helps to reduce the residual stress generated when the welding tool 30 friction-stirs the two workpieces 110, 120 to be welded.

The friction stir welding apparatus 1 of the present invention may further comprise a pair of pressing tools 50, wherein the two pressing tools 50 are respectively fixedly connected to the frame 10 and disposed at two sides of the rotating shaft module 20, the two pressing tools 50 respectively have a pressing portion 51, and when welding is performed, the pressing portions 51 of the two pressing tools 50 respectively press a workpiece to be welded and move along the welding direction along with the frame 10. The two pressing jigs 50 respectively located at two sides of the rotating shaft module 20 make the pressing range of the two workpieces 110, 120 to be welded larger, and further avoid the thinner two workpieces 110, 120 to be welded from generating angular deformation during the welding process.

The pressing portion 51 is in rolling contact with the two workpieces 110, 120, and in practice, the pressing portion 51 can achieve the rolling contact effect with the two workpieces 110, 120 by means of a roller (roller) 511 or a plurality of balls (not shown) which are annularly arranged at equal intervals.

Referring to fig. 2, the friction stir welding apparatus 1 of the present invention may further include a heating plate 60 for supporting the two workpieces 110, 120 to be welded, and for heating and maintaining the two workpieces 110, 120 to be welded, so that the temperature of the welding point of the two workpieces 110, 120 to be welded is raised and maintained at 100-200 ℃, which can improve the leveling effect on the welded workpieces, and reduce the occurrence of angular deformation.

Referring to fig. 2 and 3, when the friction stir welding apparatus 1 of the present invention is used to weld two workpieces 110, 120, first, the two workpieces 110, 120 are placed on a table (not shown), and the welding positions of the two workpieces 110, 120 are butted. If the two workpieces 110, 120 to be welded are large sheets, the jig can be fixed on the working table at the edges except the welding parts.

The friction stir welding apparatus 1 is installed on a traveling module 200 through a frame 10. The traveling module 200 at least makes the welding tool 30 of the friction stir welding device 1 push down to penetrate the welding place of the two workpieces 110, 120 to be welded at the initial welding, makes the welding tool 30 travel along the welding place of the two workpieces 110, 120 to be welded, and makes the welding tool 30 separate from the formed weld bead 130 after the welding is completed.

Next, the traveling module 200 moves the friction stir welding apparatus 1 to the starting point of the to-be-welded portion of the two to- be-welded workpieces 110, 120, as shown in the upper position of fig. 3. Then, the rotation shaft module 20 is started to rotate the inner rotation shaft 21 and the outer rotation shaft 22, and the welding tool 30 and the pressing block 40 are respectively linked to rotate. The direction of rotation of the lamination block 40 may be the same or opposite to the direction of rotation of the bonding tool 30. In the rotation process, the stirring pin 32 of the welding tool 30 is driven by the traveling module 200 to touch and pierce the to-be-welded part of the two to- be-welded workpieces 110 and 120 until the shoulder 33 abuts against the surfaces of the two to- be-welded workpieces 110 and 120. Meanwhile, the propping surface 421 of the pressing block 40 is just in contact with the surfaces of the two workpieces 110, 120 to be welded, so as to press and fix the two workpieces 110, 120 to be welded. The force with which the abutment surface 421 of the press block 40 presses against the workpieces 110, 120 is smaller than the force with which the shoulder 33 of the bonding tool 30 presses against the workpieces 110, 120.

Next, the traveling module 200 moves the friction stir welding apparatus 1 in the welding direction (indicated by the arrow in fig. 3) of the two workpieces 110, 120 to be welded, so that the welding tool 30 starts to perform friction stir welding. During the welding process, the welding tool 30 moves in the welding direction of the two workpieces 110, 120 to be welded, and the pressing block 40 also moves and remains pressed and rotated. The welding area just stirred by the welding tool 30 is still in a plastic flow state, and the continuous pressing of the pressing block 40 can reduce the buckling deformation (angular deformation) of the thinner workpieces 110, 120 to be welded along the weld bead, and can remove burrs and level the weld bead simultaneously.

During rotation, both the press block 40 and the bonding tool 30 will cause the workpieces 110, 120 to be bonded to heat up due to friction. In the foregoing operation mode, the force of the pressing surface 421 of the pressing block 40 pressing against the workpieces 110, 120 to be welded is smaller than the force of the shoulder 33 of the welding tool 30 pressing against the workpieces 110, 120 to be welded, the friction force generated by the pressing block 40 against the workpieces 110, 120 to be welded is smaller than the friction force generated by the shoulder 33 of the welding tool 30 against the workpieces 110, 120 to be welded (for convenience of description, the material of the pressing block 40 and the material of the welding tool 30 are selected to be hot tool steel, and the dynamic friction coefficient of the pressing block is the same relative to the workpieces 110, 120 to be welded), so that the friction heat provided by the pressing block 40 against the workpieces 110, 120 to be welded is smaller than the friction heat provided by the welding tool 30, and the temperature gradient of the two workpieces 110, 120 to be welded near the welding bead 130 is moderate, and the thermal stress of the workpieces to be welded can be reduced. In another mode of operation, the rotational speed of the pressing block 40 is less than the rotational speed of the welding tool 30, and the pressing block 40 provides less friction heat to the workpieces 110, 120 to be welded than the welding tool 30 in a unit time under the condition that the friction forces generated by the workpieces 110, 120 to be welded are the same, so that the temperature gradient of the two workpieces 110, 120 to be welded near the weld bead 130 is relatively mild, and the thermal stress of the welding workpieces can be reduced.

When the rotation direction of the pressing block 40 is opposite to the rotation direction of the welding tool 30, the friction force of the pressing block 40 can offset at least a portion of the torsion force applied by the welding tool 30 to the workpieces 110, 120 to be welded, and can also reduce the residual stress generated by welding.

When friction stir welding is performed, the pair of pressing jigs 50 fixedly connected to the frame body 10 can also move along the welding direction along with the frame body 10, and the pressing portions 51 of the two pressing jigs 50 respectively press a workpiece to be welded, so that the pressing and fixing forces can be further provided for the workpieces 110 and 120 to be welded, and further, the thinner two workpieces 110 and 120 to be welded can be prevented from generating angular deformation in the welding process.

After the welding operation of the workpieces 110, 120 to be welded is completed, the traveling module 200 continues to move the friction stir welding device 1 so that the welding tool 30 and the pressing block 40 are separated from the weld bead 130 formed by welding.

Fig. 4 is a cross-sectional view of another pressing block of the friction stir welding apparatus according to the present invention, please refer to fig. 4, wherein the pressing block 40 'disclosed in fig. 4 is substantially the same as that disclosed in fig. 1, except that at least one blade 43 is embedded in the pressing block 40' at the outer edge of the abutting surface 421 'of the other end 42'. When a plurality of blades 43 are embedded, the blades 43 are equidistantly arranged around the outer edge of the supporting surface 421'. During friction stir welding, the press block 40 'is rotated by the outer rotary shaft 22, and the blade 43 is also rotated along with the press block 40' to sweep the surfaces of the workpieces 110, 120 to be welded, so that the weld bead 130 and the periphery thereof can be further trimmed, and a welded workpiece with high appearance quality can be obtained. The height of the blade edge is slightly higher than the height of the propping surface 421', and the height difference between the blade edge and the propping surface is 0.01-0.1 mm, so as to avoid scratching the surfaces of the workpieces 110 and 120 to be welded.

FIG. 5 is a cross-sectional view of another pressing block of the friction stir welding apparatus according to the present invention, wherein the pressing block 40 'shown in FIG. 5 is substantially the same as that shown in FIG. 1, except that a plurality of balls 44 are embedded in the abutting surface 421' of the pressing block 40 'at the other end 42' thereof, and are circumferentially arranged at equal intervals. When friction stir welding is performed, the pressing block 40 'presses against the workpiece to be welded and rotates, and as the plurality of balls 44 are embedded in the propping surface 421', the pressing block 40 'can be in rolling contact with the workpiece to be welded, and friction heat generated by friction of the pressing block 40' on the workpiece to be welded can be reduced.

One embodiment of adjusting the clamping force of the clamping block is as follows. Fig. 6 is a cross-sectional view of a pressing block with adjustable pressing force according to the present invention, please refer to fig. 2 and 6 together, the pressing block 40 '"disclosed in fig. 6 includes an upper block 45, a lower block 46 and at least one elastic member 47, one end 41'" of the upper block 45 is connected to the outer shaft 22 of the shaft module 20, and the other end 42 '"of the lower block 46 has a supporting surface 421'" for pressing two workpieces 110, 120 to be welded. The upper block 45 and the lower block 46 each have a through hole 451, 461, and the through holes 451, 461 have the same axis (the axes coincide) for the inner shaft 21 of the shaft module 20 or the welding tool 30 to penetrate. The upper block 45 has a plurality of guide grooves 452 concavely arranged at equal intervals around the circumference, and the lower block 46 is provided with a plurality of guide pins 462 protruding at the plurality of guide grooves 452 corresponding to the upper block 45. In this embodiment, the number of the elastic members 47 is the same as the number of the guide pins 462 of the lower block 46, but not limited thereto, only one elastic member 47 may be provided. When the pressing block 40 '"of the present embodiment is assembled, the plurality of elastic members 47 are respectively inserted into the guide pins 462 of the lower block 46, the plurality of guide pins 452 of the upper block 45 are aligned with the guide pins 462 of the lower block 46, the plurality of guide pins 462 are inserted into the plurality of guide pins 452, and the plurality of elastic members 47 are sandwiched between the upper block 45 and the lower block 46 to form the pressing block 40'". The pressing block 40' ″ is penetrated into the guide grooves 452 by the guide pins 462 so that the upper block 45 and the lower block 46 can relatively move along the axial line direction of the through holes 451, 461, and the torsion force from the outer rotating shaft 22 can be transmitted from the upper block 45 to the lower block 46 to synchronously rotate. In this example, the elastic member 47 is a compression spring.

When friction stir welding is performed on the workpieces 110, 120 to be welded, the stirring pin 32 of the welding tool 30 is driven by the traveling module 200 to touch and pierce the to-be-welded part of the two workpieces 110, 120, and simultaneously, the propping surface 421'″ of the lower block 46 of the pressing block 40' ″ is also contacted with the surfaces of the two workpieces 110, 120 to be welded. The traveling module 200 continues to be depressed until the shoulder 33 of the bonding tool 30 abuts against the surfaces of the two workpieces 110, 120 to be bonded, at which time the plurality of compression springs sandwiched between the upper block 45 and the lower block 46 undergo compressive deformation by the force exerted by the traveling module 200. When the compression spring does not reach the compacting length, the product of the elastic coefficient and the deformation is the pressing force of the pressing block 40' ″ for pressing the two workpieces 110 and 120 to be welded. Thus, the desired amount of depression force can be obtained by selection of the compression spring (i.e., spring rate) and/or pre-programming of its amount of deflection.

The friction stir welding device is characterized in that a pressing block is sleeved outside a welding tool, and the pressing block moves and rotates along with the welding tool in the welding process, so that the workpiece to be welded is pressed and fixed, the thinner welding part can be reduced from buckling deformation along a welding path, the welding path can be flattened synchronously, and burrs formed by welding are removed. When the pressing block and the welding tool turn reversely, the friction force of the pressing block can offset at least one part of torsion force applied to the workpiece to be welded by the welding tool, and the residual stress formed by welding can be reduced. The welding bead and the periphery thereof can be further trimmed by embedding the blade at the outer edge of the propping surface of the pressing block, so that the welding piece with high appearance quality is obtained.

The above description of the preferred embodiments or examples of the technical means adopted to solve the problems is not intended to limit the scope of the patent implementation of the present invention. All changes and modifications that come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims (10)

1. A friction stir welding apparatus comprising:

a frame body;

a pivot module, connect in this support body, include:

an inner rotating shaft; and

an outer rotating shaft sleeved outside the inner rotating shaft;

a welding tool fixedly connected to the inner rotating shaft; and

the pressing block is sleeved on the outer side of the welding tool and fixedly connected with the outer rotating shaft;

when the welding tool performs friction stir welding on two workpieces to be welded, the pressing block rotates relative to the two workpieces to be welded and presses the two workpieces to be welded, and the force of the pressing block for pressing the two workpieces to be welded is smaller than the force of the welding tool for pressing the two workpieces to be welded.

2. The friction stir welding apparatus of claim 1 wherein the rotational direction of the outer shaft is opposite the rotational direction of the inner shaft.

3. A friction stir welding apparatus according to claim 1 or claim 2 wherein the rotational speed of the press block is less than the rotational speed of the welding tool.

4. The friction stir welding apparatus of claim 1 wherein one end of the press block is connected to the outer rotating shaft and the other end has a pressing surface for pressing the two workpieces to be welded and flattening a weld bead formed by the welding tools.

5. The friction stir welding apparatus of claim 4 wherein the outer diameter of the abutment surface is 3 times or more and 7 times or less the diameter of the pin of the welding tool.

6. The friction stir welding apparatus of claim 4 wherein the abutment surface is embedded with a plurality of balls to bring the press block into rolling contact with the two workpieces to be welded.

7. The friction stir welding apparatus of claim 4 wherein at least one blade is disposed on an outer edge of the abutment surface for trimming a weld bead and its periphery formed by the welding tool.

8. The friction stir welding apparatus of claim 4 wherein the press block comprises:

one end of the upper block is fixedly connected with the outer rotating shaft of the rotating shaft module, the other end of the upper block is concavely provided with a plurality of guide grooves which are arranged in a surrounding manner, and the upper block is provided with a first perforation;

one end of the lower block is provided with a plurality of guide pins in a protruding mode at the positions corresponding to the guide grooves of the upper block, the other end of the lower block is provided with a propping surface, the lower block is provided with a second perforation, and the first perforation and the second perforation are provided with the same axial lead and are used for the inner rotating shaft or the welding tool to penetrate and stretch; and

at least one elastic member;

when the pressing blocks are assembled, the guide pins correspondingly penetrate the guide grooves, and the at least one elastic piece is clamped between the upper block and the lower block.

9. The friction stir welding apparatus of claim 8 wherein the pressing block presses the two workpieces to be welded by an amount equal to a product of an elastic coefficient of the at least one elastic member and a deformation thereof when friction stir welding is performed.

10. The friction stir welding apparatus of claim 1 further comprising:

the pair of pressing jigs are fixedly connected to the frame body respectively and arranged on two sides of the rotating shaft module, and each pressing jig is provided with a pressing part respectively;

when welding is carried out, the pressing parts of the pair of pressing jigs respectively press a workpiece to be welded and move relative to the workpiece to be welded.

Images