An integrated tool changing tool for spot welding robots

Abstract

The present invention relates to the technical field of friction stir spot welding, and specifically to an integrated tool changing fixture for a spot welding robot. During use, the present invention lifts up the stirring needle and the stirring sleeve in sequence through a two-stage stepped shaft formed by the cooperation of a first ejector pin and a second ejector pin, and cooperates with the downward pressing action of the FSSW robot to complete the installation of the stirring needle, the stirring sleeve and the pressing sleeve in sequence. During the entire installation process, the FSSW robot only performs a segmented downward pressing action on the same plumb line, with a short action stroke and a fast speed, thereby effectively shortening the installation time. At the same time, the single plumb downward pressing action avoids its horizontal displacement, thereby reducing the space for tool changing to the vicinity of the plumb line, thereby reducing excessive space occupation. That is, the entire tool changing process can be completed quickly in a smaller space, which is a highlight of the present invention.

Description

Technical Field

[0001] The invention relates to the technical field of friction stir spot welding, in particular to an integrated tool changing tool for a spot welding robot. Background Art

[0002] In the field of workpiece welding, friction stir welding (FSW) is widely used due to its advantages such as low welding temperature and minimal weld deformation. Its derivative, FSSW (friction stir spot welding), is gradually replacing traditional spot welding. During installation, the core components of friction stir spot welding, including the stirring needle, stirring sleeve, and pressure sleeve, are first clamped by the FSSW robot. The robot then carries the stirring needle through the stirring sleeve and places the stirring sleeve on the needle. Finally, the pressure sleeve is placed on the outside of the stirring sleeve, completing the entire tool change process.

[0003] The common tool change method for FSSW robots is to place the stirring needle, stirring sleeve, and compression sleeve in different locations, and then move them to the corresponding positions for installation according to the tool change process described above. Although this tool change method can complete the replacement of welding tools, the FSSW robot needs to move to different positions, resulting in a long installation time. Furthermore, during the tool change process, the FSSW robot needs to move horizontally to three positions to complete the replacement of the stirring needle, stirring sleeve, and compression sleeve, which results in an excessively large space for the FSSW robot to change tools.

[0004] It can be seen that there is an urgent need for a device that can shorten the tool changing time and simultaneously reduce the tool changing space during the tool changing process of the FSSW robot, so as to effectively solve the above technical problems. Summary of the Invention

[0005] In order to avoid and overcome the technical problems existing in the prior art, the present invention provides an integrated tool changing tool for a spot welding robot. The present invention effectively reduces the tool changing time and the tool changing space by using the integrated tool changing tool.

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

[0007] An integrated tool changer for a spot welding robot includes a support base for placing a sequentially connected stirring needle, stirring sleeve, and compression sleeve. The support base is mounted with a telescopic lifting rod, and the telescopic end of the lifting rod is mounted with a lifting portion. The lifting portion includes a first ejector pin for vertically lifting the stirring needle upward, and a second ejector pin for vertically lifting the stirring sleeve upward. The first and second ejector pins move upward synchronously, with the top of the first ejector pin higher than the top of the second ejector pin, so as to sequentially lift the stirring needle and stirring sleeve. The first and second ejector pins are both inverted T-shaped, and the second ejector pin has an axial hole extending through its axis. The top of the first ejector pin extends upward through the axial hole and cooperates with the top of the second ejector pin to form a two-stage stepped shaft for stepwise lifting of the stirring needle and stirring sleeve.

[0008] As a further solution of the present invention: a spring sleeve is installed at the telescopic end of the lifting telescopic rod, the second ejector pin is coaxially fixed on the spring sleeve, the bottom of the first ejector pin is coaxially installed in the spring sleeve, and a lifting spring is compressed between the bottom of the first ejector pin and the inner bottom surface of the spring sleeve.

[0009] As a further solution of the present invention: the support seat includes a horizontally arranged workbench, with an axially plumb working hole penetrating the workbench; a guide sleeve is coaxially fixed in the working hole, and a connecting sleeve is coaxially fixed to the bottom end of the working hole; the lifting telescopic rod is installed at the bottom of the connecting sleeve, and its execution end is located in the connecting sleeve and fixed to the spring sleeve to push the spring sleeve to slide coaxially in the guide sleeve.

[0010] As a further solution of the present invention: the support seat also includes a contoured support member whose inner cavity shape is adapted to the outer shape of the compression sleeve and is used to support the compression sleeve with the bearing from bottom to top, and the contoured support member is elastically lifted and lowered along the vertical direction and installed on the workbench.

[0011] As a further solution of the present invention: the contoured support includes a positioning sleeve and an integrally formed positioning ring installed at the bottom of the positioning sleeve, and a two-stage stepped hole with a larger aperture at the top and a smaller aperture at the bottom is provided on the upper ring surface of the positioning ring, and each two-stage stepped hole is evenly arranged in sequence along the circumference of the positioning ring; a plurality of threaded holes are provided on the workbench along the circumference of the working hole, and the front end of the bolt passes through the two-stage stepped hole and is threadedly connected to the corresponding threaded hole. A buffer spring is coaxially sleeved on the rod of the bolt located between the positioning ring and the workbench, and the buffer spring is compressed between the positioning ring and the workbench to realize the elastic lifting and lowering installation of the contoured support.

[0012] As a further solution of the present invention: a plurality of positioning beads for radially positioning the compression sleeve are arranged in sequence along the circumference of the inner sleeve surface of the positioning sleeve, and the positioning beads include a positioning rod installed on the positioning sleeve, and a hemisphere is installed at the front end of the positioning rod. Each hemisphere encloses a positioning cavity that can cover the compression sleeve to radially position it.

[0013] As a further solution of the present invention: a plurality of positioning screw holes are uniformly opened in sequence along the circumference of the positioning sleeve, the axial direction of each positioning screw hole coincides with the radial direction of the positioning sleeve at its position, and the positioning rods are correspondingly connected to the positioning screw holes.

[0014] As a further solution of the present invention, the lifting telescopic rod and the spring sleeve are connected to each other via a floating joint.

[0015] As a further solution of the present invention, the lifting telescopic rod and the spring sleeve are connected to each other via a cylinder joint.

[0016] As a further solution of the present invention: the lifting telescopic rod is a pneumatic cylinder, an oil cylinder or an electric cylinder.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. During the use of the present invention, the two-stage stepped shaft formed by the cooperation of the first ejector pin and the second ejector pin lifts up the stirring needle and the stirring sleeve in sequence, and cooperates with the downward pressing action of the FSSW robot to complete the installation of the stirring needle, the stirring sleeve and the pressing sleeve in sequence. During the entire installation process, the FSSW robot only performs segmented downward pressing actions on the same plumb line, with a short stroke and fast speed, thus effectively shortening the installation time. At the same time, the single plumb downward pressing action avoids horizontal displacement, thereby reducing the space for tool change to the vicinity of the plumb line, thereby reducing excessive space occupation. That is, the entire tool change process can be completed quickly in a smaller space, which is a highlight of the present invention.

[0019] 2. The setting of the two-stage stepped shaft can effectively improve the integration of the first ejector and the second ejector, reduce the volume, and at the same time lift the stirring needle and the stirring sleeve in sequence, which can be said to kill two birds with one stone.

[0020] 3. The installation of the lifting spring, on the one hand, can make the first ejector pin and the second ejector pin abut against each other under the action of elastic force to form a whole, so as to effectively offset the height deviation of the stirring needle and the stirring sleeve during the lifting process, thereby achieving the purpose of lifting the stirring needle and the stirring sleeve in sequence; on the other hand, it can provide a buffer force for the mutual abutment of the first ejector pin and the stirring needle, avoiding damage to the stirring needle due to collision between the first ejector pin and the stirring needle.

[0021] 4. The installation of the buffer spring can achieve soft contact during the installation and removal of the compression sleeve. It can float up and down to unload the force, provide buffer force for the positioning sleeve, reduce the instantaneous contact impact force between the positioning sleeve and the compression sleeve, and reduce the damage to the positioning sleeve and the compression sleeve. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the internal cross-sectional structure of the present invention.

[0023] Figure 2 It is a schematic diagram of the overall structure of the present invention.

[0024] Figure 3 It is a structural schematic diagram of the workbench in the present invention.

[0025] Figure 4 It is a structural schematic diagram of the positioning sleeve in the present invention.

[0026] In the figure: 1. Support seat; 11. Workbench; 111. Working hole; 12. Positioning sleeve; 121. Positioning bead; 1211. Positioning rod; 1212. Hemisphere; 122. Positioning screw hole; 13. Positioning ring; 131. Two-stage stepped hole; 14. Bolt; 15. Buffer spring; 2. Connecting sleeve; 3. Guide sleeve; 4. Spring sleeve; 5. Floating joint; 6. Lifting telescopic rod; 71. First thimble; 72. Second thimble; 8. Lifting spring; a. Stirring needle; b. Stirring sleeve; c. Compression sleeve. DETAILED DESCRIPTION

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0028] See also Figures 1 to 4 In an embodiment of the present invention, an integrated tool changing tool for a spot welding robot includes a support base 1 composed of a workbench 11, a positioning ring 13 and a positioning sleeve 12. The workbench 11 is fixedly installed on the ground, and an axially vertically arranged working hole 111 is opened through the workbench 11. A guide sleeve 3 is coaxially fixed in the working hole 111, and a connecting sleeve 2 with an aperture larger than the aperture of the working hole 111 is coaxially fixed to the bottom end of the working hole 111. A cylinder serving as a lifting telescopic rod 6 is installed at the bottom of the connecting sleeve 2. At the same time, in order to cooperate with the extension and contraction of the cylinder, a through hole is opened at the bottom axis of the connecting sleeve 2, so that the executing end of the cylinder can pass through the through hole and extend into the connecting sleeve 2 to push the spring sleeve 4 to move up and down in the vertical direction.

[0029] In the process of pushing the cylinder up and down, in order to further improve the stability of the push, in addition to fixing the cylinder body to the bottom of the connecting sleeve 2 in a relatively firm manner, the actuator end of the cylinder is also coaxially arranged with the through hole. By pushing coaxially, the friction between the spring sleeve 4 and the guide sleeve 3 caused by the possible eccentric error is reduced as much as possible. At the same time, in order to further reduce the eccentric friction between the spring sleeve 4 and the guide sleeve 3 caused by assembly errors, a floating joint 5 is installed at the actuator end of the cylinder, and power is transmitted through the floating joint 5. Then, with the help of the gap adjustment property of the floating joint 5 itself, the eccentric friction between the spring sleeve 4 and the guide sleeve 3 is effectively eliminated to improve the smoothness of the cylinder push. In addition, the floating joint 5 can also be replaced with a corresponding cylinder joint, which is intended to correct the deviation of the spring sleeve 4 and maintain its coaxiality with the guide sleeve 3.

[0030] The second ejector pin 72 is coaxially fixed to the top of the spring sleeve 4 and is hollow in an inverted T-shape, i.e., an axial hole is formed through the axis of the second ejector pin 72. The first ejector pin 71, also in an inverted T-shape, is coaxially inserted into the axial hole from bottom to top, with its top end extending through the axial hole and cooperating with the top end of the second ejector pin 72 to form a two-stage stepped shaft, so as to facilitate the lifting of the stirring needle a and the stirring sleeve b from bottom to top.

[0031] Because the bottom of the second ejector pin 72 coaxially covers the top of the spring sleeve 4, the bottom of the first ejector pin 71 is coaxially inserted into the spring sleeve 4. To maintain the two-stage stepped shaft formed by the cooperation of the first and second ejector pins 71 and 72, a lifting spring 8 is compressed and installed between the bottom of the first ejector pin 71 and the inner bottom surface of the spring sleeve 4. This elastic lifting action of the lifting spring 8 ensures that the first and second ejector pins 71 and 72 always fit tightly together. Because the lifting spring 8 is a flexible structure, it is prone to eccentricity during operation, which in turn provides an eccentric thrust to the first ejector pin 71, resulting in eccentric friction between the first and second ejector pins 71 and 72. To effectively eliminate this eccentric friction, a positioning shaft is coaxially fixed to the bottom of the first ejector pin 71, and the lifting spring 8 is coaxially sleeved on the positioning shaft. The clearance between the positioning shaft and the lifting spring 8 is small, effectively reducing eccentric deformation of the lifting spring 8. At the same time, in order not to hinder the retraction of the first ejector 71, a certain movement gap is reserved between the bottom of the positioning shaft and the inner bottom surface of the spring sleeve 4, and the movement gap is greater than the length of the top of the first ejector 71 extending from the second ejector 72.

[0032] At this point, the first ejector pin 71 , the second ejector pin 72 , the spring sleeve 4 , the ejection spring 8 and the floating joint 5 together constitute a ejection portion installed on the top end of the cylinder.

[0033] The support seat 1 also includes a positioning sleeve 12 for supporting the bearing and pressing the sleeve c from bottom to top, and a positioning ring 13 coaxially installed on the lower side of the positioning sleeve 12, and the positioning sleeve 12 and the positioning ring 13 are integrally formed to form a contoured support member whose inner cavity shape is adapted to the outer shape of the pressing sleeve c.

[0034] The upper annular surface of the positioning ring 13 is provided with a two-stage stepped hole 131, with a larger diameter at the top and smaller diameter at the bottom. Each of these two-stage stepped holes 131 is evenly spaced along the circumference of the positioning ring 13. The workbench 11 is provided with multiple threaded holes circumferentially aligned with the working hole 111. The front end of the bolt 14 passes through the two-stage stepped hole 131 and is threadedly connected to the threaded hole to mount the contour support on the workbench 11. To mitigate the impact of the compression sleeve c on the workbench 11 during placement as the contour support slides down along the bolt 14, a buffer spring 15 is coaxially mounted on the shaft of the bolt 14 between the contour support and the workbench 11. The buffer spring 15 is elastically compressed between the contour support and the workbench 11, providing real-time buffering force for the compression sleeve c during placement, achieving soft-contact placement.

[0035] Since the contour support was initially designed to accommodate a variety of different sizes of compression sleeves (C), its fit tolerance was increased. This practice can cause some smaller compression sleeves (C) to tilt eccentrically when placed in the contour support, making them unable to align with the FSSW robot and, consequently, unable to complete tool removal and replacement. To overcome this problem, multiple positioning screw holes 122 are provided on the positioning sleeve 12 of the contour support, and positioning beads 121 are installed in each positioning screw hole 122.

[0036] Each positioning screw hole 122 is evenly arranged on the positioning sleeve 12 along the circumference of the positioning sleeve 12, and the axial direction of each positioning screw hole 122 coincides with the radial direction of the positioning sleeve 12 at its location. The positioning bead 121 includes a positioning rod 1211 and a hemispherical body 1212 coaxially mounted on the front end of the positioning rod 1211. The positioning rod 1211 with a threaded surface is threadedly connected to the positioning screw hole 122, and the hemispherical body 1212 extends out of the positioning screw hole 122, and the various positioning beads 121 extending out of the positioning screw hole 122 cooperate with each other to form a positioning cavity that radially clamps the compression sleeve c. When the contour support is working, after determining the model of the compression sleeve c, the compression sleeve c is placed in the contour support, and the conical support surface located in the positioning ring 13 at the bottom, which gradually shrinks from top to bottom, is supported on the conical surface at the bottom of the compression sleeve c. The compression sleeve c is then radially moved to align with the positioning sleeve 12. The positioning rods 1211 are then rotated sequentially until each positioning bead 121 is positioned a predetermined distance from the outer surface of the compression sleeve c. This control of the positioning cavity achieves radial positioning of the compression sleeve c, improving the positioning accuracy of the subsequent FSSW robot tool removal and expanding the applicability of the contoured support.

[0037] In one embodiment, the hemispherical body 1212 in the positioning bead 121 is elastically retracted in the positioning rod 1211 , so that the positioning bead 121 has the ability to adaptively adjust its positioning.

[0038] The function of the present invention is to realize integrated tool change, that is, when changing the tool, the stirring needle a and the stirring sleeve b are lifted up in sequence and installed on the FSSW robot, and then the clamping sleeve c is installed on the FSSW robot by pressing down, thereby completing the entire tool change process.

[0039] The specific tool changing process is as follows:

[0040] Preparation before tool changing: at least two tool changing fixtures of the present invention are arranged in the tool changing area, some of which are in an empty state for receiving welding tools that need to be replaced on the FSSW robot; other tool changing fixtures are filled with clean new welding tools.

[0041] Tool placement process: When the FSSW robot needs to change the tool, the FSSW robot moves from the working area to the tool changing area, and further moves to the top of the unloaded tool changing fixture. Then the FSSW robot moves downward, and at the same time, the cylinder of the tool changing fixture retracts the first ejector pin 71 and the second ejector pin 72 to prevent the first ejector pin 71 and the second ejector pin 72 from contacting the welding tool, providing a larger lowering space for the welding tool. After that, the FSSW robot aligns the outermost compression sleeve c of the tool head and inserts it into the positioning cavity formed by the positioning bead 121. Finally, the FSSW robot releases the welding tool, and the welding tool all falls onto the contour support; at the same time, under the buffering action of the buffer spring 15, the rigid impact between the welding tool and the contour support is minimized to reduce damage to the welding tool.

[0042] Tool Removal Process: After placing the welding tool, the FSSW robot moves directly above the tool changer, which houses the new welding tool. The FSSW robot then descends to the first welding tool installation position, while the pneumatic cylinder extends, pushing the first and second ejector pins 71 and 72 upward. As the ejector pins ascend, the first ejector pin 71 first lifts the stirring pin a to the first welding tool installation position. The robot then performs a stirring pin broaching action, attaching it to the FSSW robot. The second ejector pin 72 then lifts the stirring sleeve b to the first welding tool installation position. The robot then performs a stirring sleeve broaching action, attaching it to the FSSW robot. The pneumatic cylinder then retracts, resetting the first and second ejector pins 71 and 72. At this point, both the stirring pin a and the stirring sleeve b are attached to the FSSW robot. Finally, the FSSW robot continues its downward movement to the second welding tool installation position, gradually contacting the compression sleeve c during this movement. The robot then performs a compression sleeve broaching action, ultimately attaching the compression sleeve c to the FSSW robot at the second welding tool installation position. At this point, the tool change process is completed, and the FSSW robot then returns to its original path and continues its previous processing work.

[0043] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. An integrated tool changer for a spot welding robot, characterized in that: The invention comprises a support base (1) for placing a stirring needle (a), a stirring sleeve (b) and a pressing sleeve (c) which are connected in sequence, a lifting telescopic rod (6) being installed on the support base (1), and a lifting part being installed at the telescopic end of the lifting telescopic rod (6); the lifting part comprises a first thimble (71) for vertically lifting the stirring needle (a) and a second thimble (72) for vertically lifting the stirring sleeve (b), the first thimble (71) and the second thimble (72) moving upward synchronously. The top of the first ejector pin (71) is higher than the top of the second ejector pin (72) so as to sequentially lift the stirring needle (a) and the stirring sleeve (b); the first ejector pin (71) and the second ejector pin (72) are both inverted T-shaped, and an axial hole is provided through the axis of the second ejector pin (72); the top of the first ejector pin (71) passes through the axial hole upward and cooperates with the top of the second ejector pin (72) to form a two-stage stepped shaft for lifting the stirring needle (a) and the stirring sleeve (b) in steps.

2. The integrated tool changing tool for a spot welding robot according to claim 1, characterized in that: The telescopic end of the lifting telescopic rod (6) is installed with a spring sleeve (4), the second ejector pin (72) is coaxially fixed on the spring sleeve (4), the bottom of the first ejector pin (71) is coaxially installed in the spring sleeve (4), and a lifting spring (8) is compressed between the bottom of the first ejector pin (71) and the inner bottom surface of the spring sleeve (4).

3. The integrated tool changing tool for a spot welding robot according to claim 2, characterized in that: The support seat (1) includes a horizontally arranged workbench (11), and an axially vertically arranged work hole (111) is opened through the workbench (11); a guide sleeve (3) is coaxially fixed in the work hole (111), and a connecting sleeve (2) is coaxially fixed at the bottom end of the work hole (111); the lifting telescopic rod (6) is installed at the bottom of the connecting sleeve (2), and its execution end is located in the connecting sleeve (2) and is fixed to the spring sleeve (4) to push the spring sleeve (4) to slide coaxially in the guide sleeve (3).

4. An integrated tool changing tool for a spot welding robot according to any one of claims 1 to 3, characterized in that: The support seat (1) also includes a contoured support member whose inner cavity shape matches the outer shape of the compression sleeve (c) and is used to support the compression sleeve (c) from bottom to top, and the contoured support member is elastically lifted and lowered on the workbench (11) along the vertical direction.

5. The integrated tool changing tool for a spot welding robot according to claim 4, characterized in that: The contour support comprises a positioning sleeve (12) and a positioning ring (13) integrally formed and mounted on the bottom of the positioning sleeve (12); a two-stage stepped hole (131) with a larger diameter at the top and a smaller diameter at the bottom is provided on the upper ring surface of the positioning ring (13); and each of the two-stage stepped holes (131) is evenly arranged in sequence along the circumference of the positioning ring (13); a plurality of threaded holes are provided on the workbench (11) along the circumference of the working hole (111); the front end of the bolt (14) passes through the two-stage stepped hole (131) and is threadedly connected with the corresponding threaded hole; a buffer spring (15) is coaxially sleeved on the rod of the bolt (14) located between the positioning ring (13) and the workbench (11), and the buffer spring (15) is compressed between the positioning ring (13) and the workbench (11) to realize the elastic lifting installation of the contour support.

6. The integrated tool changing tool for a spot welding robot according to claim 5, characterized in that: A plurality of positioning beads (121) for radially positioning the compression sleeve (c) are sequentially arranged on the inner sleeve surface of the positioning sleeve (12) along its circumference. The positioning beads (121) include a positioning rod (1211) mounted on the positioning sleeve (12). A hemisphere (1212) is mounted at the front end of the positioning rod (1211). The hemispheres (1212) enclose and form a positioning cavity that can cover the compression sleeve (c) to radially position it.

7. The integrated tool changing tool for a spot welding robot according to claim 6, characterized in that: A plurality of positioning screw holes (122) are uniformly provided on the positioning sleeve (12) along its circumference, and the axial direction of each positioning screw hole (122) coincides with the radial direction of the positioning sleeve (12) at its location, and the positioning rod (1211) is correspondingly connected to the positioning screw hole (122).

8. The integrated tool changing tool for a spot welding robot according to claim 2, characterized in that: The lifting telescopic rod (6) and the spring sleeve (4) are connected to each other via a floating joint (5).

9. The integrated tool changing tool for a spot welding robot according to claim 2, characterized in that: The lifting telescopic rod (6) and the spring sleeve (4) are connected to each other via a cylinder joint.

10. The integrated tool changing tool for a spot welding robot according to claim 1, characterized in that: The lifting telescopic rod (6) is an air cylinder, an oil cylinder or an electric cylinder.

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