An end effector for pipe fitting grinding and a robotic arm

Abstract

The present invention relates to the field of automation technology, and discloses an end effector and a robotic arm for pipe fitting grinding, including a mounting plate, a grinding part and a first motor. The grinding part includes a rotating seat driven by the first motor to rotate, a guide groove recessed on the side of the rotating seat away from the mounting plate, and a guide block that moves along the guide of the guide groove. A grinding head extending out of the rotating seat is fixed on the side of the guide block away from the mounting plate. The movement of the guide block is controlled by a driving mechanism. The driving mechanism includes a lead screw passing through the guide block in the guide groove and rotatably connected to both ends of the guide groove. A nut cooperating with the lead screw is fixed on the guide block. A second motor for driving the lead screw to rotate is fixed on the mounting plate. A switching mechanism for driving the lead screw to switch between locking and rotation is arranged at one end of the rotating seat close to the second motor. This actuator can achieve continuous grinding of the inner and outer walls of pipe fittings of different sizes, and both the applicability and production efficiency are significantly improved.

Description

Technical Field

[0001] The present invention relates to the field of automation technology, and specifically to an end effector and a robotic arm for pipe fitting grinding. Background Art

[0002] A robotic end effector refers to any tool with a certain function connected to the edge of a robot. The end effector includes a robot tool quick change device, a robot collision sensor, a robot rotary connector, a robot pressure tool, a robot grinding tool, a robot spray gun, and so on.

[0003] In pipe fitting grinding, there are two grinding methods. The first is that the workpiece is fixed and the grinding tool rotates, which is mostly applicable to the grinding of the inner wall of the pipe fitting. The size of the grinding head is adapted to the inner wall of the pipe fitting. When the grinding head rotates self - sufficiently, it grinds the inner wall of the workpiece. The second is that the workpiece rotates and the grinding tool is fixed, which is generally applicable to the grinding of the outer wall of the pipe fitting. The grinding head is tangent to the outer wall of the pipe fitting. As the pipe fitting rotates, the grinding head grinds the outer wall of the pipe fitting. Of course, there are also some improved designs that use different grinding heads to grind the outer wall of the pipe fitting. For example, a metal pipe fitting surface grinding device disclosed in a Chinese patent with the publication number CN214869171U includes a grinding cylinder and a clamping and fixing mechanism. The clamping and fixing mechanism is used to clamp the metal pipe fitting. The clamping and fixing mechanism is connected to a motor. Driven by the motor, the metal pipe fitting can rotate self - sufficiently. The grinding cylinder is fixed on an electric telescopic column and can reciprocate along the axial direction of the metal pipe fitting as the electric telescopic column expands and contracts. As the metal rotating part rotates, the grinding cylinder grinds the outer wall of the metal pipe fitting.

[0004] The existing grinding methods can only grind the outer wall or the inner wall of the pipe fitting, and cannot be applied to the grinding of both the inner and outer walls of the pipe fitting at the same time. For pipe fittings that require grinding of both the inner and outer walls, they need to be ground in different processes on two devices. Moreover, when grinding pipe fittings of different sizes, the types of grinding tools need to be continuously changed, resulting in high equipment costs and low production efficiency. Summary of the Invention

[0005] Aiming at the problems of high cost and low production efficiency of the existing grinding tools, the first object of the present invention is to provide an end effector for pipe fitting grinding with wide applicability and capable of improving production efficiency.

[0006] To solve the above technical problems, the present invention provides the following technical solution: An end effector for pipe fitting grinding, comprising a mounting plate, a grinding part rotatably arranged on the mounting plate, and a first motor fixed on the mounting plate. The grinding part includes a rotating seat driven by the first motor to rotate, a guide groove recessed on the side of the rotating seat away from the mounting plate, and a guide block moving along the guide of the guide groove. A grinding head extending out of the rotating seat is fixed on the side of the guide block away from the mounting plate. The movement of the guide block is controlled by a driving mechanism. The driving mechanism includes a lead screw passing through the guide block in the guide groove and rotatably connected to both ends of the guide groove. A nut cooperating with the lead screw is fixed on the guide block. A second motor for driving the lead screw to rotate is fixed on the mounting plate. A switching mechanism for driving the lead screw to switch between locking and rotating is arranged at one end of the rotating seat close to the second motor. The switching mechanism includes a telescopic block elastically telescoping at one end of the lead screw close to the second motor. A limiting groove is recessed at one end of the rotating seat close to the second motor. A limiting block protruding from one end of the telescopic block close to the rotating seat and capable of being inserted into the limiting groove when the telescopic block retracts is provided. An electromagnetic adsorption mechanism for driving the telescopic block to expand and contract is arranged between the limiting groove and the limiting block. A non-circular insertion block fixed at the end of the motor shaft of the second motor, and a non-circular insertion slot recessed at one end of the telescopic block close to the second motor and for the non-circular insertion block to be inserted into when the telescopic block extends out is provided.

[0007] According to the above solution, this end effector includes a mounting plate and a grinding part rotatable thereon. The grinding part includes a grinding head fixed on a guide block. The guide block can reciprocally move along the axial direction of the lead screw as the lead screw rotates, realizing the adjustment of the distance between the grinding head and the rotation center of the rotating seat. When the rotating seat rotates, the grinding head orbits around the rotation center of the rotating seat to grind the inner ring wall or outer ring wall of the pipe fitting. When it is necessary to grind the inner and outer walls of pipe fittings with different diameters, only the second motor needs to be used to drive the lead screw to rotate to adjust the distance between the grinding head and the rotation center of the rotating seat. When the grinding head grinds the pipe fitting, it is necessary to ensure that the lead screw is in a stationary state to guarantee the grinding accuracy. The switching mechanism in the present invention can realize the switching of the lead screw between rotation and locking. The switching mechanism includes a telescopic block and an electromagnetic adsorption mechanism. The electromagnetic adsorption mechanism realizes the adsorption or desorption of the telescopic block with the presence or absence of magnetism. When the electromagnetic adsorption mechanism has magnetism, the telescopic block is in a retracted state and the limiting block on the telescopic block is inserted and matched with the limiting groove, and the lead screw is locked on the rotating seat; when the electromagnetic adsorption mechanism has no magnetism, the telescopic block automatically pops out and elastically abuts against or is directly inserted and matched with the motor shaft of the second motor. If it is in an elastic abutting state, as the second motor rotates, the non-circular insertion block at the end of the motor shaft of the second motor can automatically be inserted into the non-circular insertion slot, driving the lead screw to rotate as the second motor rotates. The structure is very ingenious. This end effector can continuously grind the inner and outer walls of pipe fittings with different diameters successively without replacing the grinding head. While the applicability is significantly improved, the equipment cost is reduced, and the production efficiency is significantly increased.

[0008] Further, the electromagnetic adsorption mechanism includes an electromagnet fixedly arranged in the limiting groove. The extension of the telescopic block is controlled by an elastic member, and the limiting block is made of a material that can be adsorbed by a magnet.

[0009] According to the above solution, when the electromagnet is powered on, the limiting block is adsorbed by the electromagnet and drawn into the limiting groove. At this time, the telescopic block disengages from the motor shaft of the second motor. The plug-in fit between the limiting block and the limiting groove locks the lead screw on the rotating seat. At this time, the grinding head cannot move along the axial direction of the lead screw. When the electromagnet is powered off, the telescopic block is in the extended state under the action of the elastic member. The limiting block moves with the telescopic block and disengages from the limiting groove. After the telescopic block extends, it is plugged into the non-circular plug block on the motor shaft of the second motor, and the lead screw rotates synchronously with the rotation of the motor shaft of the second motor, realizing the change of the axial position of the grinding head along the lead screw.

[0010] Further, a non-circular sliding groove is recessed at one end of the lead screw close to the second motor. The telescopic block includes a telescopic rod that can be fully retracted into the non-circular sliding groove or partially extended out of the non-circular sliding groove, and a mating block perpendicularly fixed to the end of the telescopic rod away from the lead screw. The limiting block is fixed to one end of the mating block close to the lead screw.

[0011] According to the above solution, the telescopic block can only move along the length direction of the non-circular sliding groove and cannot rotate. When the mating block is locked with the rotating seat, the lead screw cannot rotate relative to the mating block, and the lead screw is stationary relative to the rotating seat.

[0012] Further, the elastic member is a spring. The spring can be arranged in the non-circular sliding groove or sleeved on the telescopic rod. When the spring is arranged in the non-circular sliding groove, the two ends of the spring are respectively connected or elastically abutted against the bottom of the non-circular sliding groove and the end of the telescopic rod. When the spring is sleeved on the telescopic rod, the two ends of the spring are respectively elastically abutted against the end of the rotating seat and one end of the mating block close to the rotating seat.

[0013] According to the above solution, whether the spring is arranged in the non-circular sliding groove or sleeved on the telescopic rod can realize the elastic reset of the mating block.

[0014] Further, the limiting grooves and the limiting blocks are in one-to-one correspondence and are uniformly arranged at intervals circumferentially around the rotation center of the lead screw. At least one electromagnet is fixed to the bottom of the limiting groove.

[0015] According to the above solution, after multiple limiting grooves and limiting blocks are provided, the locking accuracy can be improved.

[0016] Further, on the side of the rotating seat away from the mounting disc, an indicating scale for indicating the position of the grinding head is arranged along the moving direction of the guide block at the opening of the guide groove.

[0017] According to the above solution, the indicating scale can facilitate manual focusing or observation.

[0018] Further, there are two guiding blocks which can approach or move away from each other synchronously. A grinding head is fixed on each guiding block. The two grinding heads are of the same size and are arranged in parallel. The lead screw is a bidirectional lead screw. The two guiding blocks are respectively located on two thread segments with opposite helix directions of the bidirectional lead screw. The connection of the two thread segments of the bidirectional lead screw corresponds to the "0" scale of the indicating scale.

[0019] According to the above solution, after adopting the bidirectional lead screw, the two grinding heads can approach or move away from each other synchronously, which can improve the uniformity and efficiency of grinding when grinding pipe fittings.

[0020] Further, the grinding head is detachably arranged on the guiding block. A non-circular insertion section protrudes from one end of the guiding block away from the mounting disc. A mating groove for inserting the non-circular insertion section is recessed at one end of the grinding head close to the guiding block. A locking screw is arranged on the outer wall of one end of the grinding head close to the guiding block and passes through the grinding head to fix with the non-circular insertion section.

[0021] According to the above solution, after the grinding head is detachably arranged, it is convenient for installation or replacement. Due to the setting of the non-circular insertion section on the guiding block, the grinding head can be centered and the connection strength between the two can be increased.

[0022] Further, a guiding and load-bearing mechanism is arranged between the rotating seat and the mounting disc. The guiding and load-bearing mechanism includes a guiding ring groove recessed at one end of the mounting disc close to the rotating seat with the motor shaft of the first motor as the center, and at least one guiding block protruding from one end of the rotating seat close to the mounting disc and inserted into the guiding ring groove.

[0023] According to the above solution, the rotating seat is guided and fitted with the guiding ring groove on the mounting disc through the guiding block, which ensures that the rotation center of the rotating seat does not shift and improves the firmness of the connection between the rotating seat and the mounting disc at the same time.

[0024] The second object of the present invention is to provide a robotic arm, the end of which is connected with the above-mentioned end effector for pipe fittings.

[0025] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0026] 1. This end effector includes a mounting plate and a grinding part rotatably disposed thereon. The grinding part includes a grinding head, which is fixed on a guide block. The guide block can reciprocate axially along the lead screw as the lead screw rotates, so as to adjust the distance between the grinding head and the rotation center of the rotating seat. When the rotating seat rotates, the grinding head orbits around the rotation center of the rotating seat to grind the inner wall or outer wall of the pipe fitting. When it is necessary to grind the inner and outer walls of pipe fittings with different diameters, only need to drive the lead screw to rotate by the second motor to adjust the distance between the grinding head and the rotation center of the rotating seat. When the grinding head grinds the pipe fitting, it is necessary to ensure that the lead screw is in a stationary state to guarantee the grinding accuracy. And the switching mechanism in this invention can realize the switching between the rotation and locking of the lead screw. The switching mechanism includes a telescopic block and an electromagnetic adsorption mechanism. The electromagnetic adsorption mechanism realizes the adsorption or desorption of the telescopic block with the presence or absence of magnetism. When the electromagnetic adsorption mechanism has magnetism, the telescopic block is in a retracted state and the limit block on the telescopic block is inserted and matched with the limit groove, and the lead screw is locked to the rotating seat. When the electromagnetic adsorption mechanism has no magnetism, the telescopic block automatically pops out and elastically abuts against or is directly inserted and matched with the second motor shaft. If it is in an elastic abutting state, as the second motor rotates, the non-circular insertion block at the end of the motor shaft of the second motor can automatically insert into the slot, driving the lead screw to rotate as the second motor rotates. The structure is very ingenious. This end effector can continuously grind the inner and outer walls of pipe fittings with different diameters successively without replacing the grinding head. While the applicability is significantly improved, the equipment cost is reduced and the production efficiency is significantly increased.

[0027] 2. A bidirectional lead screw is adopted, and guide blocks are respectively arranged on two threaded segments of the bidirectional lead screw. The same grinding heads are fixed on each guide block. During grinding, the two grinding heads orbit around the rotation center of the first motor at the same time. When grinding the pipe fitting, the grinding uniformity and grinding efficiency can be improved. Description of the Drawings

[0028] The drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation to the present invention. In the drawings:

[0029] Figure 1 is an isometric view of an end effector for grinding pipe fittings in this embodiment;

[0030] Figure 2 is Figure 1 an enlarged view of A of

[0031] Figure 3 is a front view of an end effector for grinding pipe fittings in this embodiment;

[0032] Figure 4 is Figure 3 a cross-sectional view taken along A-A of

[0033] Figure 5 is Figure 4 an enlarged view of B;

[0034] Figure 6 is a cross-sectional view when the end effector for pipe fitting grinding in this embodiment grinds the inner wall of the pipe fitting;

[0035] Figure 7 is a cross-sectional view when the end effector for pipe fitting grinding in this embodiment grinds the outer wall of the pipe fitting.

[0036] In the figure: 1. mounting disc; 2. guiding ring groove; 3. rotating seat; 301. rotating shaft; 302. guiding block; 4. guiding groove; 5. lead screw; 501. non-circular sliding groove; 6. guiding block; 7. grinding head; 8. second motor; 9. telescopic block; 901. telescopic rod; 902. mating block; 9021. non-circular slot; 10. limiting groove; 11. limiting block; 12. spring; 13. indicating scale; 14. non-circular inserting section; 15. locking screw; 16. first motor; 17. mounting block; 18. non-circular inserting block; 19. electromagnet. Specific Embodiment

[0037] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention.

[0038] Embodiment

[0039] A robotic arm equipped with an end effector for pipe fitting grinding includes an end effector provided at the end of the robotic arm. The end effector is shown in reference to Figures 1-5 and includes a mounting disc 1. On one side of the mounting disc 1, a mounting block 17 that is hinged or fixedly connected to the robotic arm protrudes. At one end of the mounting disc 1 away from the mounting block 17, a grinding portion is provided. The interior of the mounting disc 1 is hollow and fixedly provided with a first motor 16. The grinding portion includes a rotating seat 3. At the center of the side of the rotating seat 3 close to the mounting disc 1, a rotating shaft 301 that protrudes and is fixedly connected to the end of the motor shaft of the first motor 16 is inserted into the interior of the mounting disc 1. The rotating shaft 301 and the mounting disc 1 are rotatably connected through a bearing. The rotating shaft 301 is fixedly connected to the inner ring of the bearing, and the mounting disc 1 is fixedly connected to the outer ring of the bearing. On the side of the rotating seat 3 away from the mounting disc 1, a guiding groove 4 is recessed. The cross-section of the guiding groove 4 is non-circular. In this embodiment, a rectangle is adopted. A guiding block 6 is guided to move in the guiding groove 4. The cross-section of the guiding block 6 is rectangular. On the side of the guiding block 6 away from the mounting disc 1, a grinding head 7 that extends out of the rotating seat 3 is fixed. The grinding head 7 in this embodiment adopts a columnar grinding head 7. The movement of the guiding block 6 is controlled by a driving mechanism. The driving mechanism includes a lead screw 5 that passes through the guiding block 6 in the guiding groove 4 and is rotatably connected to both ends of the guiding groove. A nut that cooperates with the lead screw 5 is fixed on the guiding block 6. The rotation of the lead screw 5 is controlled by a second motor 8.

[0040] The rotating base 3 rotates relatively fast during grinding. Setting the second motor 8 on the rotating base 3 to rotate with the rotating base has great difficulty in setting and causes greater damage to the second motor 8. Therefore, in this embodiment, the second motor 8 is fixed on the mounting plate 1, and a switching mechanism that can drive the lead screw 5 to switch between locking and rotation is provided at one end of the rotating base 3 close to the second motor 8. Combining Figure 2 , Figure 4 and Figure 5 shown, the switching mechanism can realize the connection or disconnection with the motor shaft of the second motor 8. The specific structure is as follows: it includes a non-circular chute 501 recessed at one end of the lead screw 5 close to the second motor 8 and a telescopic block 9. The telescopic block 9 includes a telescopic rod 901 that can be fully retracted into the non-circular chute 501 or partially extended out of the non-circular chute 501, and a mating block 902 vertically fixed at one end of the telescopic rod 901 away from the lead screw 5. The cross-section of the telescopic rod 901 is non-circular. In this embodiment, a rectangle is adopted. A limiting convex block for limiting its sliding out of the non-circular chute 501 is provided at one end of the telescopic rod 901 away from the mating block 902. An insertion limiting mechanism is provided between the mating block 902 and the opposite side of the rotating base 3. The insertion limiting mechanism includes a fixed ring embedded in the rotating base 3 centered on the lead screw 5 and limiting grooves 10 circumferentially and evenly spaced around the fixed ring centered on the lead screw 5. Limiting blocks 11 corresponding to the limiting grooves 10 one by one are protruded on one side of the mating block 902 close to the rotating base 3. The insertion or detachment of the limiting blocks 11 from the limiting grooves 10 is controlled by an electromagnetic adsorption mechanism.

[0041] The electromagnetic adsorption mechanism includes an electromagnet 19 fixedly arranged in at least one limiting groove 10. In this embodiment, referring to Figure 5 shown, the electromagnet 19 includes a main body and adsorption protrusions protruding from the main body and inserted into each limiting groove 10. In this way, only one electromagnet 19 is needed. Of course, each adsorption protrusion can also be independently arranged. Only when controlling, all the adsorption protrusions are connected in series or parallel in a circuit. The limiting blocks 11 are made of a material that can be adsorbed by a magnet. In this embodiment, the limiting blocks 11 are made of iron. The reset of the telescopic block 9 after the electromagnet 19 loses power is controlled by an elastic member. The elastic member can adopt a spring 12. The spring 12 has at least two setting methods. One is to be built into the non-circular chute 501 and elastically abutted or fixedly connected to the bottom of the non-circular chute 501 and the limiting convex block at both ends respectively; the other is to be sleeved outside the telescopic rod 901 and elastically abutted and matched with one end of the mating block 902 close to the rotating base 3 and the end of the rotating base 3 at both ends respectively. In this embodiment, the latter is adopted.

[0042] At one end of the mating block 902 away from the lead screw 5, a non-circular slot 9021 is recessed in the center. The motor shaft of the second motor 8 faces the lead screw 5 and a non-circular plug 18 that can be inserted into the non-circular slot 9021 is fixed at the end. When the electromagnet 19 loses power, the telescopic block 9 extends and can drive the non-circular plug 18 to be inserted into the non-circular slot 9021. At this time, the lead screw 5 rotates with the rotation of the second motor 8. When the electromagnet 19 is powered on, the telescopic block 9 retracts away from the second motor 8 and the limiting block 11 on the telescopic block 9 is inserted into the limiting groove 10 on the rotating seat 3, and the lead screw 5 is locked on the rotating seat 3. The power-on or power-off of the electromagnet 19 is controlled by a control circuit, and the control circuit includes the electromagnet 19 and a control switch connected in series.

[0043] On the side of the rotating seat 3 away from the mounting disc 1, at the opening of the guide groove 4, an indicating scale 13 for indicating the position of the grinding head 7 is arranged along the moving direction of the guide block 6. Refer to Figure 3 As shown, in this embodiment, in order to improve the grinding efficiency, the lead screw 5 used is a bidirectional lead screw 5. The bidirectional lead screw includes two thread segments with opposite helix directions. A guide block 6 is arranged on each of the two thread segments, and a nut for cooperating with the thread segment is arranged on each guide block 6. A grinding head 7 is fixed on the side of each guide block 6 away from the mounting disc 1. The connection point of the two thread segments of the bidirectional lead screw 5 corresponds to the "0" scale of the indicating scale 13. As the bidirectional lead screw 5 rotates, the two guide blocks 6 can approach or move away from the "0" scale simultaneously.

[0044] In order to facilitate the replacement of the grinding head 7, the grinding head 7 is detachably arranged on the guide block 6. Refer to Figure 4 As shown, at one end of the guide block 6 away from the mounting disc 1, a non-circular plug-in section 14 protrudes. At one end of the grinding head 7 close to the guide block 6, a mating groove for the non-circular plug-in section 14 to be inserted is recessed. A through hole communicating with the mating groove is arranged on the grinding head 7. A threaded hole is arranged on the non-circular plug-in section 14, and a locking screw 15 passing through the through hole and tightly mating with the threaded hole is arranged on the outer wall of the end of the grinding head 7 close to the guide block 6. The cross-section of the non-circular plug-in section 14 is square and is arranged at the center of the guide block 6. The above connection method is convenient for the replacement of the grinding head 7 and can also ensure the connection strength between the grinding head 7 and the guide block 6.

[0045] In order to ensure the rotation accuracy of the rotating seat 3 and the safety of its connection with the mounting seat, a guiding and load-bearing mechanism is arranged between the rotating seat 3 and the mounting disc 1. Combining Figure 1 and Figure 4 As shown, the guiding and load-bearing mechanism includes a guiding ring groove 2 recessed at one end of the mounting disc 1 close to the rotating seat 3 with the motor shaft of the first motor 16 as the center, and at least one guiding block 302 protruding from one end of the rotating seat 3 close to the mounting disc 1 and inserted into the guiding ring groove 2. In this embodiment, two guiding blocks 302 are arranged and symmetrically arranged on both sides of the rotating shaft 301.

[0046] The above-mentioned first motor 16 and second motor 8 are both servo motors or stepper motors. A controller and a touch screen are provided on the robotic arm. The controller is a PLC. The first motor 16, the second motor 8, the control switch, and the touch screen are all connected to the controller. Programs can be edited through the touch screen. The opening and closing, rotation speed of the first motor 16 and the second motor 8, and the opening and closing of the control switch are all realized by the existing logic programming of the controller, which will not be elaborated here.

[0047] After the target pipe fitting is fixed on the fixture, the distance between the two grinding heads 7 is adjusted according to the actual grinding part (outer wall and / or inner wall). Taking a pipe fitting with an outer diameter of 3 CM, an inner diameter of 2.5 CM, and requiring grinding on both the inner and outer walls as an example, refer to Figures 6-7 as shown, the specific operation steps are as follows:

[0048] 1. The first motor 16 is in the off state, the electromagnet 19 is in the de-energized state, the telescopic block 9 extends and is inserted and matched with the non-circular insert block 18 at the end of the second motor 8. After the second motor 8 rotates to adjust the distance between the opposite sides of the two grinding heads 7 to be greater than 3 CM, the robotic arm moves until the two grinding heads 7 are sleeved on the outer wall of the pipe fitting, and then the second motor 8 rotates in the reverse direction to drive the distance between the opposite sides of the grinding heads 7 to be adjusted to 3 CM. At this time, the grinding heads 7 are tangent to the outer wall of the pipe fitting;

[0049] 2. The second motor 8 is turned off, the electromagnet 19 is energized, the telescopic block 9 retracts to drive the limit block 11 on it to be inserted and matched with the limit block 11 on the rotating seat 3, and the two grinding heads 7 are locked on the rotating seat 3;

[0050] 3. The first motor 16 is started, the rotating seat 3 rotates with the first motor 16, and the two grinding heads 7 rotate around the outer wall of the pipe fitting to grind the outer wall of the pipe fitting;

[0051] 4. After the outer wall of the pipe fitting is ground, the first motor 16 is turned off, the electromagnet 19 is de-energized again, the telescopic block 9 extends and is inserted and matched with the non-circular insert block 18 at the end of the second motor 8. If the insertion is not achieved, the second motor 8 can be driven to rotate until it is inserted and matched with the telescopic block 9. After the second motor 8 rotates until the distance between the opposite sides of the two grinding heads 7 is greater than 3 CM again, the robotic arm moves to drive the grinding heads 7 away from the pipe fitting;

[0052] 5. The second motor 8 rotates in the reverse direction until the distance between the opposite sides of the two grinding heads 7 is less than 2.5 CM, and then the robotic arm moves to drive the grinding heads 7 to insert into the inner wall of the pipe fitting. The second motor 8 rotates forward until the distance between the opposite sides of the two grinding heads 7 is 2.5 CM, ensuring that the two grinding heads 7 are tangent to the inner wall of the pipe fitting at the same time;

[0053] 6. The second motor 8 is turned off, the electromagnet 19 is energized, the telescopic block 9 retracts to drive the limit block 11 on it to be inserted and matched with the limit block 11 on the rotating seat 3, and the two grinding heads 7 are locked on the rotating seat 3;

[0054] 7. The first motor 16 starts, and the rotating seat 3 rotates with the first motor 16. The two grinding heads 7 revolve along the outer wall of the pipe fitting to grind the inner wall of the pipe fitting.

[0055] 8. After the inner wall of the pipe fitting is ground, the first motor 16 is turned off, and the electromagnet 19 is de-energized again. The telescopic block 9 extends out and is inserted and matched with the end of the second motor 8. After the second motor 8 rotates to make the distance between the opposite sides of the two grinding heads less than 2.5 cm, the robotic arm moves to drive the grinding heads 7 away from the pipe fitting.

[0056] The above completes the continuous automatic grinding of the outer wall and the inner wall of a pipe fitting. If only the outer wall or the inner wall of the pipe fitting needs to be ground, the robotic arm can be operated by changing the program. Therefore, the applicability of the end effector for grinding this pipe fitting has been significantly improved. And because the inner and outer walls of the pipe fitting can be continuously ground, the production efficiency has been significantly improved. The structure of this grinding tool is ingenious but not cumbersome, easy to produce, and the equipment cost is not much different from that of an existing single-function device. Therefore, the equipment cost has actually decreased significantly.

[0057] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An end effector for pipe fitting grinding, comprising a mounting plate (1), a grinding part rotatably arranged on the mounting plate (1), and a first motor (16) fixed on the mounting plate (1). Characterized in that: The grinding part includes a rotating seat (3) driven by a first motor (16) to rotate, a guide groove (4) recessed on the side of the rotating seat (3) away from the mounting plate (1), and a guide block (6) guided to move along the guide groove (4). A grinding head (7) extending out of the rotating seat (3) is fixed on the side of the guide block (6) away from the mounting plate (1). The movement of the guide block (6) is controlled by a driving mechanism. The driving mechanism includes a lead screw (5) passing through the guide block (6) in the guide groove (4) and rotatably connected to both ends of the guide groove (4). A nut cooperating with the lead screw (5) is fixed on the guide block (6). A second motor (8) for driving the lead screw (5) to rotate is fixed on the mounting plate (1). A switching mechanism for driving the lead screw (5) to switch between locking and rotation is arranged at one end of the rotating seat (3) close to the second motor (8); The switching mechanism includes a telescopic block (9) elastically telescoped at one end of the lead screw (5) close to the second motor (8). A limiting groove (10) is recessed at one end of the rotating seat close to the second motor (8). A limiting block (11) protruding from one end of the telescopic block (9) close to the rotating seat and capable of inserting into the limiting groove (10) when the telescopic block (9) retracts is provided. An electromagnetic adsorption mechanism for driving the telescopic block (9) to expand and contract is arranged between the limiting groove (10) and the limiting block (11). A non-circular insertion block (18) fixed to the end of the motor shaft of the second motor (8), and a non-circular insertion slot (9021) recessed at one end of the telescopic block (9) close to the second motor (8) for the non-circular insertion block (18) to insert when the telescopic block (9) extends; The electromagnetic adsorption mechanism includes an electromagnet (19) fixedly arranged in the limiting groove (10). The extension of the telescopic block (9) is controlled by an elastic member. The limiting block (11) is made of a material that can be adsorbed by a magnet; A non-circular sliding groove (501) is recessed at one end of the lead screw (5) close to the second motor (8). The telescopic block (9) includes a telescopic rod (901) that can be fully retracted into the non-circular sliding groove (501) or partially extended out of the non-circular sliding groove (501), and a matching block (902) vertically fixed to the end of the telescopic rod (901) away from the lead screw (5). The limiting block (11) is fixed to one end of the matching block (902) close to the lead screw (5); The elastic member is a spring (12). The spring (12) can be arranged in the non-circular sliding groove (501) or sleeved on the telescopic rod (901). When the spring (12) is arranged in the non-circular sliding groove (501), both ends of the spring (12) are respectively connected or elastically abutted to the bottom of the non-circular sliding groove (501) and the end of the telescopic rod (901); When the spring (12) is sleeved on the telescopic rod (901), both ends of the spring (12) are respectively elastically abutted to the end of the rotating seat (3) and one end of the matching block (902) close to the rotating seat (3); The limiting grooves (10) and the limiting blocks (11) are in one-to-one correspondence and a plurality of them are circumferentially and evenly spaced around the rotation center of the lead screw (5). At least one electromagnet is fixed to the bottom of the limiting groove (10).

2. An end effector for pipe fitting grinding according to claim 1, characterized in that: On the side of the rotating base (3) away from the mounting plate (1) at the opening of the guide groove (4), an indicating scale (13) for indicating the position of the grinding head (7) is provided along the moving direction of the guide block (6).

3. The end effector for pipe fitting grinding according to claim 2, characterized in that: There are two guide blocks (6) which can approach or move away from each other synchronously. A grinding head (7) is fixed on each guide block (6). The two grinding heads (7) are of the same size and are arranged in parallel. The lead screw (5) is a bidirectional lead screw. The two guide blocks (6) are respectively located on two thread segments with opposite helix directions of the bidirectional lead screw. The connection of the two thread segments of the bidirectional lead screw (5) corresponds to the "0" scale of the indicating scale (13).

4. The end effector for pipe fitting grinding according to claim 1, characterized in that: The grinding head (7) is detachably arranged on the guide block (6). At the end of the guide block (6) away from the mounting plate (1), a non-circular insertion section (14) protrudes. At the end of the grinding head (7) close to the guide block (6), a mating groove for the non-circular insertion section (14) to insert is recessed. On the outer wall of the end of the grinding head (7) close to the guide block (6), a locking screw (15) is provided which passes through the grinding head (7) and is fixed to the non-circular insertion section (14).

5. The end effector for pipe fitting grinding according to claim 1, characterized in that: A guiding and load-bearing mechanism is arranged between the rotating base (3) and the mounting plate (1). The guiding and load-bearing mechanism includes a guiding ring groove (2) recessed with the motor shaft of the first motor (16) as the center at the end of the mounting plate (1) close to the rotating base (3) and at least one guiding block (302) protruding at the end of the rotating base (3) close to the mounting plate (1) and inserted into the guiding ring groove (2).

6. A robotic arm, characterized in that: The end thereof is connected with the end effector for pipe fitting grinding according to any one of claims 1-5.

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