Apparatus and method for automatic grooving and welding repair of impeller cracks

Abstract

The application provides equipment for impeller crack automatic opening and welding repair, which comprises a ball screw mechanism, one side of the ball screw mechanism is connected with an extension mechanism, the end of the extension mechanism is connected with a three-joint mechanical arm, the end of the three-joint mechanical arm is connected with an AVC mechanism, one side of the AVC mechanism is detachably connected with a front end milling mechanism or a front end welding mechanism, both sides of the ball screw mechanism are provided with clamping mechanisms, and the ball screw mechanism is connected to the lower blade through the clamping mechanisms. The application can be applied to narrow space (between impellers), and the trajectory planning and milling and welding of the front end movement are realized by the movement structure of the guide rail and the mechanical arm. The front end cylinder for milling provides sufficient axial milling force for the milling process, and solves the problem of insufficient rigidity caused by the long cantilever structure of the extension mechanism and the mechanical arm.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of welding, and particularly relates to an equipment and method for automatic groove opening and welding repair of impeller cracks. BACKGROUND

[0002] Large impellers used in hydropower stations are prone to fatigue cracks as the service time is prolonged, and regular inspection and repair of cracks are of great significance to the stable operation of the impeller unit. However, due to the spiral blades of the impeller, the distance between the cracks in the impeller and the narrow part between the upper and lower blades is only 300 mm, the manual repair work is heavy and the space is limited, making it difficult to operate. The current popular mechanical arm cannot be used to open the groove and weld inside. In addition, during the groove opening process, it is difficult for the series mechanical arm to obtain stable support and the milling force is difficult to guarantee. The present application proposes a new type of automatic groove milling device to realize the method of automatic repair of impeller groove milling and welding in a limited space. SUMMARY

[0003] The present application belongs to the technical field of welding, and particularly relates to an equipment and method for automatic groove opening and welding repair of impeller cracks.

[0004] Technical scheme: The equipment for automatic groove opening and welding repair of impeller cracks comprises a ball screw mechanism, one side of the ball screw mechanism is connected with a telescopic mechanism, the end of the telescopic mechanism is connected with a three-joint mechanical arm, the end of the three-joint mechanical arm is connected with an AVC mechanism, one side of the AVC mechanism is detachably connected with a front end milling mechanism or a front end welding mechanism, both sides of the ball screw mechanism are provided with clamping mechanisms, and the ball screw mechanism is connected to the lower blade through the clamping mechanisms.

[0005] Preferably, the ball screw mechanism comprises a ball screw sliding table, a ball screw motor, a ball screw limit lever, a limit switch support, a limit switch, a ball screw top cover, a screw rod, a ball screw guide rail, a ball screw guide rail fixing hole, a screw rod guide rail sliding block, a screw nut and a ball screw mechanism bottom plate.

[0006] The ball screw motor is arranged on one side of the lower blade, the driving end of the ball screw motor is connected with the screw rod, the screw nut is connected to the screw rod to drive the ball screw sliding table, the ball screw sliding table is slidingly connected to the screw rod guide rail sliding block, the ball screw guide rail is connected to the ball screw mechanism bottom plate through the ball screw guide rail fixing hole, and the screw rod guide rail sliding block is connected to the ball screw guide rail.

[0007] The ball screw limit lever is connected to the ball screw sliding table, the limit switch support is connected to the ball screw mechanism side plate, and the limit switch is connected to the limit switch support.

[0008] Preferably, the telescopic mechanism comprises a telescopic box, one side of the telescopic box is provided with a first telescopic arm, one side of the first telescopic arm is provided with a second telescopic arm, and the end of the second telescopic arm is connected to the three-joint mechanical arm.

[0009] Preferably, the three-joint mechanical arm comprises a first mechanical arm joint, a second mechanical arm joint, and a third mechanical arm joint, the end of the third mechanical arm joint is connected with the AVC mechanism, and the three-joint mechanical arm rotates in three planes in space.

[0010] Preferably, the AVC mechanism comprises an AVC shell, an AVC motor, an AVC screw end plate, an AVC screw end plate fixing hole, an AVC slider guide rod, an AVC screw nut slider, an AVC screw nut slider fixing hole, an AVC screw, and an AVC screw bearing support.

[0011] The AVC shell is connected to the end of the third mechanical arm joint, the AVC motor is fixed at the bottom of the AVC shell and drives the AVC screw connected thereto, the AVC screw end plate is connected to the bottom of the AVC shell through the AVC screw end plate fixing hole, one end of the AVC slider guide rod is connected to the AVC screw end plate, and the other end is connected to the AVC screw bearing support, the AVC screw nut slider is connected to the AVC slider guide rod and the AVC screw, the AVC screw bearing support is connected below the shell, and the AVC screw nut slider is connected to the head mounting support through the AVC screw nut slider fixing hole.

[0012] Preferably, one side of the AVC mechanism is connected to a head mounting support, and the head mounting support is provided with a front end milling mechanism or a front end welding mechanism.

[0013] Preferably, the front end milling mechanism comprises two symmetrical cylinder structures, the driving end of each of the two cylinder structures is connected with a universal bead support plate, a universal bead base is arranged above the two universal bead support plates, a universal bead is embedded on the two universal bead bases, the universal bead base and the universal bead support plate are connected through bolts, a pressure sensor is connected below each of the two cylinder structures, the pressure sensor and the head mounting support are connected through bolts, a milling motor is connected to the head mounting support through a motor support, one end of the milling motor penetrates the head mounting support and is connected with a milling cutter chuck and a milling cutter, and the upper side of each of the two universal beads is connected with an upper blade.

[0014] Preferably, the cylinder mechanism comprises a cylinder piston rod, a cylinder rod side end cover, a cylinder barrel, a cylinder pull rod, and a cylinder rodless side end cover, the cylinder piston rod and the universal bead support plate are welded together, and the pressure sensor is connected below the cylinder rodless side end cover.

[0015] Preferably, the front end welding mechanism is detachably connected to the upper end of the machine head mounting support, and a front end welding mechanism mounting block is arranged above the front end welding mechanism.

[0016] Preferably, the clamping mechanism comprises three switch type strong magnetic bases, each of which is provided with a magnetic switch, two of which are arranged on the left side of the ball screw mechanism, and one of which is arranged on the right side of the ball screw mechanism, and the upper sides of the three switch type strong magnetic bases are connected to one side of the ball screw mechanism through bolts, respectively.

[0017] The method for automatically opening a groove and welding repair of a cracked impeller comprises the following steps:

[0018] 1) Place the device on the lower blade, turn on the magnetic switches of the three switch type strong magnetic bases, and fix the device on the lower blade.

[0019] 2) Set the working path and the axial force according to the milling depth, and after setting, the control system sends a driving signal to the ball screw mechanism, the telescopic mechanism, the three-joint mechanical arm, the AVC mechanism, the milling motor, and the cylinder mechanism according to the setting, at this time, the milling cutter starts the milling work, in this process, the pressure sensor monitors the axial force of the front end milling mechanism in real time, if the detection value is not equal to the set value, the calculation module adjusts and sends a signal value to the cylinder structure, the cylinder structure adjusts to make the detection pressure value consistent with the set value in real time, so that the front end milling mechanism is self-adaptive to the height of the blade during the working process, and the cutting axial force is kept constant during the process.

[0020] 3) After the milling operation is completed, the front end milling mechanism is replaced with a front end welding mechanism for welding operation.

[0021] Advantages:

[0022] 1. In the narrow space (between the impellers), the trajectory planning and milling and welding of the front end movement are realized by using the combined movement structure of the guide rail and the mechanical arm.

[0023] 2. The milling front end cylinder provides sufficient axial milling force for the milling process, solving the problem of insufficient rigidity caused by the long cantilever structure of the telescopic mechanism and the mechanical arm.

[0024] 3. The cylinder can self-adaptively adjust the height of the telescopic rod between the narrow blades, so that the milling mechanism is self-adaptive to the height of the blade during the working process, and the cutting axial force is kept constant during the process.

[0025] 4. The milling cutter moves along the trajectory of the weld as a spatial curve, and the universal ball can realize universal movement in the milling process, and is suitable for impeller curved surfaces.

[0026] 5. The front end replaceable mechanism is used for milling operation by the front end milling mechanism, and is used for welding operation by the front end welding mechanism after the milling operation is completed. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is the overall structure of the device of the present application;

[0028] Figure 2 is the ball screw mechanism of the present application;

[0029] Figure 3 is the AVC mechanism of the present application;

[0030] Figure 4 is the front end milling mechanism of the present application;

[0031] Figure 5 is the front view of the device of the present application;

[0032] Figure 6 is the system workflow and control method of the present application.

[0033] Telescopic box 1, first telescopic arm 2, second telescopic arm 3, ball screw sliding table 4, first mechanical arm joint 5, ball screw limit rod 6, ball screw motor 7, L-shaped support mounting hole 8, L-shaped support 9, magnetic switch 10, limit switch support 11, switch type strong magnetic table base 12, limit switch 13, second mechanical arm joint 14, third mechanical arm joint 15, AVC mechanism 16, machine head mounting support 17, ball screw top cover 18, screw 19, ball screw guide rail 20, ball screw guide rail fixing hole 21, universal ball 22, universal ball base 23, universal ball support plate 24, air cylinder piston rod 25, air cylinder rod side end cover 26, milling motor 27, air cylinder cylinder 28, air cylinder pull rod 29, air cylinder rod side end cover 30, pressure sensor 31, milling cutter chuck 32, milling cutter 33, front end milling mechanism 34, lower blade 35, front end welding mechanism mounting block 36, front end welding mechanism 37, motor support 38, upper blade 39, screw guide rail slider 40, screw nut 41, ball screw mechanism bottom plate 42, ball screw mechanism side plate 43, AVC motor 44, AVC screw end plate 45, AVC screw end plate fixing hole 46, AVC slider guide rod 47, AVC screw nut slider 48, AVC screw nut slider fixing hole 49, AVC screw 50, AVC screw bearing support 51, AVC machine shell 52. DETAILED DESCRIPTION

[0034] The present application will be further explained in conjunction with the accompanying drawings.

[0035] The overall structure of the impeller crack automatic opening and welding filling device is shown in Figure 1 The entire device is mainly composed of a telescopic box (1), a telescopic arm 1 (2), a telescopic arm 2 (3), a ball screw mechanism composed of a ball screw sliding table (4), a mechanical arm joint 1 (5), a ball screw limiting lever (6), a ball screw motor (7), an L-shaped support mounting hole (8), an L-shaped support (9), a magnetic switch (10), a limiting switch support (11), a switch type strong magnetic table base (12), a limiting switch (13), a mechanical arm joint 2 (14), a mechanical arm joint 3 (15), an AVC mechanism (16), a machine head mounting support (17), a ball screw top cover (18), a screw rod (19), a ball screw guide rail (20), a ball screw guide rail fixing hole (21), a universal ball (22), a universal ball base (23), a universal ball support plate (24), a cylinder piston rod (25), a cylinder rod side end cover (26), a milling motor (27), a cylinder barrel (28), a cylinder pull rod (29), a cylinder rodless side end cover (30), a pressure sensor (31), a milling cutter chuck (32), a milling cutter (33), a lower blade (35), a front end welding mechanism (37), a milling motor support (38), and an upper blade (39).

[0036] The ball screw mechanism is composed of the ball screw sliding table (4), the ball screw motor (7), the ball screw limiting lever (6), the limiting switch support (11), the limiting switch (13), the ball screw top cover (18), the screw rod (19), the ball screw guide rail (20), the ball screw guide rail fixing hole (21), a screw rod guide rail sliding block (40), a screw rod nut (41), and a ball screw mechanism bottom plate (42), and the main function is to drive the entire system main body structure to move horizontally through the ball screw sliding table (4). The telescopic mechanism is composed of the telescopic box (1) telescopic arm 1 (2) and the telescopic arm 2 (3), and the telescopic box (1) bottom is connected with the ball screw sliding table (4) through bolts, and the telescopic arm 2 (3) is connected with the mechanical arm joint 1 (5). The main function of the telescopic mechanism is to drive the milling cutter (33) to move vertically and in the direction of the guide rail through the telescopic arm. The three-joint mechanical arm is composed of the mechanical arm joint 1 (5), the mechanical arm joint 2 (14), and the mechanical arm joint 3 (15), and the three-joint mechanical arm can rotate the milling cutter (33) in three spatial planes, and can control the three-joint mechanical arm through an algorithm to adjust the position of the milling cutter (33) in the curve normal direction in real time when milling the impeller curve. The AVC mechanism (16) is connected with the machine head mounting support (38) and drives the front end milling mechanism (34) to move up and down.

[0037] Before the equipment starts working, it is first positioned and clamped. The clamping function is achieved by three switch-type strong magnetic bases (12). There are a total of three switch-type strong magnetic bases (12) in the entire equipment, two on the left and one on the right. The upper sides of the two switch-type strong magnetic bases (12) on the left are respectively connected to one side of two L-shaped brackets (9) by bolts. The other side of the L-shaped brackets (9) is connected to the left side of the ball screw mechanism by bolts. Similarly, the switch-type strong magnetic base (12) on the right, the L-shaped bracket (9) and the right side of the ball screw mechanism are fixed in the same way. After the equipment position is determined, the magnetic switches (10) of the switch-type strong magnetic bases (12) on the left and right are turned on, so that the entire equipment can be fixed on the lower blade (35).

[0038] Since the telescopic arms 1 (2), 2 (3), three-joint robotic arm, and AVC mechanism connecting the milling cutter are cantilever structures, and the milling cutter needs sufficient downward axial force during milling, such a cantilever structure is insufficient to provide it. Therefore, a new type of front-end milling mechanism is proposed.

[0039] Front-end milling mechanism such as Figure 2 As shown, the main components are: two universal joint mechanisms, two cylinder devices, two pressure sensors (31), a milling motor (27), a milling cutter (33), and a milling head mounting bracket (17). The universal joint (22) is embedded inside the universal joint base (23), and the universal joint base (23) is bolted to the universal joint support plate (24). The cylinder mechanism consists of a cylinder piston rod (25), a cylinder rod-side end cap (26), a cylinder barrel (28), a cylinder tie rod (29), and a cylinder rodless side end cap (30). The cylinder piston rod (25) is welded to the universal joint support plate (24), and a pressure sensor (31) is connected below the cylinder rodless side end cap (30). The pressure sensor (31) is bolted to the milling head mounting bracket (17). The milling motor (27) is connected to the milling head mounting bracket (17) via a motor bracket (38).

[0040] During milling operations, the lead screw nut slider (48) is connected to the front milling mechanism (34) through the lead screw nut slider fixing hole (49), and can be adjusted up and down. During welding operations, the lead screw nut slider (48) is connected to the front welding mechanism (37) through the lead screw nut slider fixing hole (49), and the height of the front welding mechanism (37) is adjusted in real time by detecting the arc voltage, so that the welding arc pressure remains constant.

[0041] The front milling mechanism of the patent is supported by a cylinder, which can provide sufficient axial milling force for the milling process, solving the problem of insufficient rigidity caused by the long extension mechanism and mechanical arm cantilever structure. In addition, since the impeller is a spatial curved surface, the milling cutter moves along a spatial curve during milling. The universal bead used in the patent can realize universal movement during milling, which is suitable for impeller curved surfaces.

[0042] The front milling mechanism of the patent is supported by a cylinder, which can provide sufficient axial milling force for the milling process, solving the problem of insufficient rigidity caused by the long extension mechanism and mechanical arm cantilever structure. In addition, since the impeller is a spatial curved surface, the milling cutter moves along a spatial curve during milling. The universal bead used in the patent can realize universal movement during milling, which is suitable for impeller curved surfaces. Figure 3 As shown in the front view of the device, When milling, set the corresponding axial force according to the milling depth, and the pressure sensor (31) detects the axial force of the milling mechanism in real time. When the detected axial force is less than the set value, the cylinder piston rod (25) rises, causing the universal bead (22) to rise, giving the upper blade (39) an upward force, allowing the milling cutter to obtain downward axial force.

[0043] During cutting, the distance between the blades will change in real time. Since the cylinder has a pressure sensor (31) installed on the lower side, the cylinder can adaptively adjust the height of the support mechanism cylinder piston rod (25) in the narrow space according to the set and detected axial force value, allowing the milling mechanism to adapt to the blade height during operation, and keeping the cutting axial force constant during this process.

[0044] When the milling operation is complete, the front milling mechanism is removed and the front welding structure (37) is installed. The front welding mechanism is a complete module, and the welding mechanism mounting block (36) can be connected to the AVC mechanism (16) by bolts. The two mechanisms use quick-release installation cooperation mechanisms to make the replacement process simple and efficient.

[0045] Figure 4 The system workflow and control method block diagram is shown in First, position the device on the lower blade, then open the strong magnetic table seat to clamp the device on the lower blade, set the working path, and set the axial force according to the milling depth. After setting, the control system sends driving signals to the ball screw mechanism, extension mechanism, three-joint mechanical arm, AVC mechanism, milling motor, and cylinder mechanism according to the settings. At this time, the milling cutter starts milling work. During this process, the pressure sensor monitors the axial force of the milling mechanism in real time. If the detected value is not equal to the set value, the calculation module calculates and adjusts the signal value of the cylinder, making the detected pressure value consistent with the set value in real time. This allows the milling mechanism to adapt to the blade height during operation and keeps the cutting axial force constant during this process. When the milling operation is complete, replace the front milling mechanism with the welding mechanism for welding operation.

[0046] The above merely describes the preferred embodiments of the present application, and it should be pointed out that, for those skilled in the art, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as falling within the protection scope of the present application.

Claims

1. Equipment for automatic beveling and welding repair of impeller cracks, characterized in that, The device includes a ball screw mechanism, one side of which is connected to a telescopic mechanism. The end of the telescopic mechanism is connected to a three-joint robotic arm. The end of the three-joint robotic arm is connected to an AVC mechanism (16). One side of the AVC mechanism (16) is detachably connected to a front milling mechanism (34) or a front welding mechanism (37). Both sides of the ball screw mechanism are provided with clamping mechanisms. The ball screw mechanism is connected to the lower blade (35) through the clamping mechanisms. The AVC mechanism (16) includes an AVC housing (52), an AVC motor (44), an AVC lead screw end plate (45), an AVC lead screw end plate fixing hole (46), an AVC slider guide rod (47), an AVC lead screw nut slider (48), an AVC lead screw nut slider fixing hole (49), an AVC lead screw (50), and an AVC lead screw bearing support (51). The AVC housing (52) is connected to the end of the three-joint robotic arm. The AVC motor (44) is fixed to the bottom of the AVC housing (52) and drives the AVC screw (50). The AVC screw end plate (45) is connected to the bottom of the AVC housing (52) through the AVC screw end plate fixing hole (46). One end of the AVC slider guide rod (47) is connected to the AVC screw end plate (45), and the other end is connected to the AVC screw bearing support (51). The AVC screw nut slider (48) is connected to the AVC slider guide rod (47) and the AVC screw (50). The AVC screw bearing support (51) is connected to the bottom of the AVC housing (52). The AVC screw nut slider (48) is connected to the machine head mounting support (17) through the AVC screw nut slider fixing hole (49). The front milling mechanism (34) includes two symmetrical cylinder structures. The drive ends of the two cylinder structures are connected to universal ball support plates (24). Universal ball bases (23) are provided above the two universal ball support plates (24). Universal balls (22) are embedded on the two universal ball bases (23). The universal ball bases (23) and the universal ball support plates (24) are connected by bolts. Pressure sensors (31) are connected below the two cylinder structures. The pressure sensors (31) are connected to the head mounting bracket (17) by bolts. The milling motor (27) is connected to the head mounting bracket (17) through the motor bracket (38). One end of the milling motor (27) passes through the head mounting bracket (17) and is connected to the milling cutter chuck (32) and the milling cutter (33). The upper side blades (39) are contacted above the two universal balls (22).

2. The equipment for automatic beveling and welding repair of impeller cracks as described in claim 1, characterized in that, The ball screw mechanism includes a ball screw slide (4), a ball screw motor (7), a ball screw limit lever (6), a limit switch support (11), a limit switch (13), a ball screw top cover (18), a screw (19), a ball screw guide rail (20), a ball screw guide rail fixing hole (21), a screw guide rail slider (40), a screw nut (41), and a ball screw mechanism base plate (42). The ball screw motor (7) is located on one side of the lower blade (35). The drive end of the ball screw motor (7) is connected to the screw (19). The screw nut (41) is connected to the screw (19) to drive the ball screw slide (4). The ball screw slide (4) is slidably connected to the screw guide rail slider (40). The ball screw guide rail (20) is connected to the ball screw mechanism base plate (42) through the ball screw guide rail fixing hole (21). The screw guide rail slider (40) is connected to the ball screw guide rail (20). The ball screw limit lever (6) is connected to the ball screw slide (4), the limit switch support (11) is connected to the side plate (43) of the ball screw mechanism, and the limit switch (13) is connected to the limit switch support (11).

3. The equipment for automatic beveling and welding repair of impeller cracks as described in claim 1, characterized in that, The telescopic mechanism includes a telescopic box (1), a first telescopic arm (2) is provided on one side of the telescopic box (1), a second telescopic arm (3) is provided on one side of the first telescopic arm (2), and the end of the second telescopic arm (3) is connected to the three-joint mechanical arm.

4. The equipment for automatic beveling and welding repair of impeller cracks as described in claim 1, characterized in that, The three-joint robotic arm includes a first robotic arm joint (5), a second robotic arm joint (14), and a third robotic arm joint (15). The end of the third robotic arm joint (15) is connected to the AVC mechanism (16). The three-joint robotic arm rotates in three planes of space.

5. The equipment for automatic beveling and welding repair of impeller cracks as described in claim 4, characterized in that, The AVC mechanism (16) is connected to a head mounting bracket (17) on one side, and the head mounting bracket (17) is provided with a front milling mechanism (34) or a front welding mechanism (37).

6. The equipment for automatic beveling and welding repair of impeller cracks as described in claim 1, characterized in that, The cylinder structure includes a cylinder piston rod (25), a cylinder rod-side end cap (26), a cylinder barrel (28), a cylinder tie rod (29), and a cylinder rodless side end cap (30). The cylinder piston rod (25) is welded together with the universal ball support plate (24), and the pressure sensor (31) is connected below the cylinder rodless side end cap (30).

7. The equipment for automatic beveling and welding repair of impeller cracks as described in claim 1, characterized in that, A front welding mechanism (37) is detachably connected to the head mounting bracket (17). A front welding mechanism mounting block (36) is provided above the front welding mechanism (37). The front welding mechanism (37) is connected to the head mounting bracket (17) through the front welding mechanism mounting block (36).

8. The equipment for automatic beveling and welding repair of impeller cracks as described in claim 1, characterized in that, The clamping mechanism includes three switch-type strong magnetic bases (12), each of which is equipped with a magnetic switch (10). Two of the switch-type strong magnetic bases (12) are located on the left side of the ball screw mechanism, and one is located on the right side of the ball screw mechanism. The upper sides of the three switch-type strong magnetic bases (12) are respectively connected to one side of the L-shaped bracket (9) by bolts. The other side of the L-shaped bracket (9) is connected to one side of the ball screw mechanism by bolts through the L-shaped bracket mounting hole (8).

9. A method for automatic beveling and welding repair of impeller cracks, using the equipment described in claim 1, characterized in that, Includes the following steps: 1): Place the device on the lower blade, turn on the magnetic switches of the three switch-type strong magnetic bases, and fix the device on the lower blade; 2): Set the working path and set the axial force according to the milling depth. After setting, the control system sends drive signals to the ball screw mechanism, telescopic mechanism, three-joint robotic arm, AVC mechanism, milling motor, and cylinder structure according to the setting. At this time, the milling cutter starts milling. During this process, the pressure sensor monitors the axial force of the front milling mechanism in real time. If the detected value is not equal to the set value, the calculation module calculates and adjusts, sends a signal value to the cylinder structure, and the cylinder structure makes adjustments to make the detected pressure value consistent with the set value in real time. This allows the front milling mechanism to adapt to the height of the blade during the working process and keeps the cutting axial force constant during this process. 3): After the milling operation is completed, the front milling mechanism is replaced with the front welding mechanism to perform the welding operation.

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