A hole aligning device for large hydro-turbine fine boring and an operation method thereof

Abstract

The application discloses a hole aligning device for fine boring of a large water turbine and an operation method thereof, and relates to the technical field of hole aligning devices. The hole aligning device comprises a boring cutter bar, a dial indicator, and a rotating connecting assembly. The boring cutter bar is provided with a threaded hole. The dial indicator is rotatably arranged at the front end of the boring cutter bar through the rotating connecting assembly. The rotating connecting assembly comprises a mounting seat. The mounting seat is locked on the threaded hole of the boring cutter bar through a screw. The dial indicator and the boring cutter bar can be arranged at the same position. When the boring cutter bar performs secondary hole aligning on the boring hole of the boring template, the position of the dial indicator is consistent with the installation position of the last dial indicator, and the dial indicator is firmly installed, so that the boring cutter bar is not damaged or violently adsorbed.

Description

Technical Field

[0001] This invention relates to the field of precision boring technology for water turbines, and in particular to a hole-calibrating device for precision boring of large water turbines and its operating method. Background Technology

[0002] When machining the motor shaft and the rotor connected to the generator set separately on a CNC floor-type milling and boring machine, in order to ensure coaxiality and assembly connection accuracy, a boring template is required to ensure the pin hole machining accuracy during the machining of the motor shaft and rotor.

[0003] Traditional methods for aligning the dial indicator involve either using a magnetic base to hold it securely at the end of the boring bar, or using a different opening to clamp the dial indicator holder, ensuring the boring bar and boring die hole are concentric, followed by precision boring. However, the position of the dial indicator is difficult to guarantee perfectly consistent each time, introducing indirect errors and resulting in unsatisfactory machining outcomes. During assembly, misalignment of the connecting holes between the motor shaft and rotor is discovered, preventing the pin from being installed. This necessitates individual fitting, but the dimensions of the fitted parts vary, affecting quality and efficiency, thus leading to poor versatility and increased manufacturing costs.

[0004] The main structure of a hydroelectric turbine includes the main shaft, runner, motor shaft, and casing. The main shaft connects to both the runner and motor shaft, which in turn connects to the generator rotor. To ensure assembly accuracy, it is often necessary to machine bored pin holes on the shaft, rotor, and runner for positioning. However, in large hydroelectric units, the motor shaft and rotor are often machined separately due to their large diameter and tonnage, making it difficult to guarantee concentricity and causing difficulties in later assembly. Therefore, boring templates are used for machining the motor shaft and main shaft to ensure boring accuracy. Typically, the combined length of the flange holes of both shafts exceeds 600mm, and the design clearance between the pin and the hole is within 0.03mm-0.04mm. Therefore, ensuring coaxiality and perpendicularity is very challenging. During the boring process, the long overhang of the boring bar, coupled with the gravity exerted by the dial indicator, causes misalignment errors exceeding design requirements.

[0005] For example, Chinese Patent Publication No. CN101623770A, published on January 13, 2010, entitled "Horizontal Boring Machine Long Hole Reversing Boring Method," has the following steps: 1) Clamp the long hole workpiece on the horizontal boring machine's worktable; 2) Rough bore the entire inner hole; 3) Machining the empty tool hole; 4) Finish boring one end of the inner hole; 5) Rotate the horizontal boring machine's worktable 180°; 6) Adjust the horizontal boring machine's spindle to be coaxial with the axis of the long hole. Mount the long boring bar on the spindle of the horizontal boring machine. Install the dial indicator rod into the square tenon hole at the end of the long boring bar. Adjust the position of the dial indicator contact so that it contacts the inner hole surface after precision boring, and compress the dial indicator needle by 0.5mm. Rotate the spindle of the horizontal boring machine, and control the dial indicator needle fluctuation within 0.01mm. 7) Remove the long boring bar and install the short boring bar. 8) Precision bore the inner hole at the other end.

[0006] The drawback of the existing patent is that when the dial indicator is attached to the boring bar by a magnetic base during the precision boring and calibration of large water turbines, the position of the dial indicator cannot be guaranteed to be consistent during the secondary calibration, resulting in calibration error and misalignment of the connecting holes during the assembly of the water turbine. Summary of the Invention

[0007] The purpose of this invention is to solve the problem that in existing large-scale hydraulic turbine precision boring and calibration methods, the dial indicator is magnetically attached to the boring bar, which cannot guarantee the consistency of the dial indicator's position during secondary calibration, resulting in calibration errors and misalignment of connecting holes during turbine assembly. This invention provides a calibration device and its operating method for large-scale hydraulic turbine precision boring, which provides a precise positioning dial indicator, improves the consistency of the dial indicator during secondary calibration, and greatly reduces calibration errors.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A hole-calibrating device for precision boring of large hydraulic turbines includes a boring bar with a threaded hole, and a dial indicator. The dial indicator is rotatably mounted on the front end of the boring bar via a rotating connecting assembly. The rotating connecting assembly includes a mounting base, which is screwed onto the threaded hole of the boring bar. In this device, the dial indicator is mounted via the rotating connecting assembly. The boring bar has an imperial threaded hole, and the mounting base of the rotating connecting assembly has a fixing hole that mates with the threaded hole. The screw passes through the fixing hole of the mounting base and is threadedly locked into the threaded hole, ensuring that the dial indicator is positioned at the same location as the boring bar. When the boring bar performs secondary hole calibration on the boring die hole of the boring template, the dial indicator is installed in the same and secure position as in the previous step, preventing damage to the boring bar or damage from forceful suction. This improves the service life of the boring bar.

[0009] Preferably, the mounting base includes a connecting portion and an abutting portion. One end of the connecting portion is fixedly connected to the outer wall of the boring bar by screws, and the other end is connected to the abutting portion. The connecting portion is located on the side wall of the boring bar, and the abutting portion is located on the front end face of the boring bar. The connecting portion is distributed along the central axis of the boring bar, and the abutting portion is arranged parallel to the front end face of the boring bar. The connecting portion and the abutting portion form an L-shaped structure. Further optimization of the abutting portion involves providing a rubber pad on the side of the abutting portion facing the end face of the boring bar to prevent the abutting portion from bumping or damaging the boring bar.

[0010] Preferably, the rotating connection assembly further includes a first connecting rod and a second connecting rod. The rear end of the first connecting rod is fixed to the mounting base, and the front end of the first connecting rod is rotatably connected to the second connecting rod via a first rotating member. The dial indicator is rotatably connected to the front end of the second connecting rod via the second rotating member. The central axis of the first connecting rod coincides with or is parallel to the central axis of the boring bar. The coincidence or parallel arrangement of the central axis of the first connecting rod with the central axis of the boring bar serves to support the dial indicator. The first and second connecting rods are rotatably connected via the first rotating member, and the dial indicator and the second connecting rod are rotatably connected via the second rotating member, allowing the dial indicator to rotate in various directions. This enables multi-directional measurements such as axial and radial measurements, making the hole-calibrating device in this solution adaptable to motor shafts, main shafts, rotors, etc., of different specifications of water turbines, and suitable for boring templates of different specifications, thus broadening its applicability.

[0011] Preferably, the boring bar is provided with a boring head, and the bolt hole is located at a 45-degree angle to the boring head connection. The rotating connection assembly and the boring head of the boring bar do not interfere with each other. Compared with the magnetic base, the rotating connection in this solution is compatible with boring bars of different specifications. The threaded hole on the boring bar is an imperial threaded hole. Therefore, the rotating connection in this solution can be universally used on boring bars of different specifications, and is not affected by the end face area of ​​the boring bar or the boring head.

[0012] Preferably, the first rotating component includes a first U-shaped clamping component sleeved on the first connecting rod and a first locking bolt for locking the first U-shaped clamping component. A guide block is provided on the outer side of the first U-shaped clamping component. The second connecting rod passes through and slides within the guide block. The first locking bolt passes through the first U-shaped clamping component, is threaded onto the guide block, and abuts against the side wall of the second connecting rod. The first connecting rod slides within the first U-shaped clamping component, and the clamping component locks the first connecting rod with the first locking bolt. Simultaneously, the first locking bolt locks the second connecting rod, fixing the first and second connecting rods at the desired angle. The angle and total length of the first and second connecting rods are adjusted via a first connecting component. The rotating connecting component in this solution is adaptable to boring bar holders of different specifications. The threaded hole on the boring bar is an imperial threaded hole; therefore, the rotating connecting component in this solution can be universally used on boring bar holders of different specifications and is adaptable to boring templates of different specifications.

[0013] Preferably, the second rotating component includes a second U-shaped clamping member sleeved on the sleeve of the dial indicator and a second locking bolt for locking the second U-shaped clamping member. A fixing block is provided on the outer side of the second U-shaped clamping member. The second locking bolt passes through the second U-shaped clamping member and is threadedly locked to the fixing block. The fixing block is located at the front end of the second connecting rod. The second rotating component facilitates the rotation of the dial indicator, and the second U-shaped clamping member is used to clamp the dial indicator onto the second U-shaped clamping member. The second U-shaped clamping member is fixed to the front end of the second connecting rod by the fixing block.

[0014] The operating method of the hole-calibrating device for precision boring of a large water turbine as described in any of the above-mentioned methods includes a boring template, wherein the boring template is provided with boring die holes, and includes the following steps in sequence: Step 1: Before precision boring any pin hole, select the corresponding boring die hole on the boring template, align it with the inner circle of the boring die hole as a reference, fix one end of the rotating connection assembly to the threaded hole of the boring bar with screws, and set up a dial indicator on the other end, and mate the dial indicator with the boring die hole; Step 2: Mark four cross directions (up, down, left, right) on the outer sidewall of the boring die hole. Rotate the dial indicator on each of the four cross directions of the boring die hole using the boring bar. At this time, the dial indicator readings on all four cross directions of the boring die hole should be 0mm. Then, set the machine tool coordinates to zero (X0, Y0), remove the rotating connection assembly, and keep the dial indicator clamped on the rotating connection assembly. Perform a test boring on the boring die hole with the minimum amount of boring, leaving a mark on the inner wall of the boring die hole. Step 3: Reinstall the rotating connection assembly and dial indicator at the front end of the boring bar. Re-round the mark bored in Step 2. Rotate the dial indicator on the boring bar to calibrate the roundness in the four cross directions of the boring die hole. When the actual reading on the left and right is 0mm to 0mm, the actual readings on the top and bottom are -Amm and +Bmm. The difference between the top and bottom is the dial indicator setting on the boring bar. Record the dial indicator setting data. Step 4: Move the boring bar a certain distance along the Z-axis of the machine tool spindle towards the depth of the boring die hole, avoiding the test boring marks from Step 2. Align it according to the original inner circle of the boring die hole. Use the dial indicator to rotate the boring bar to calibrate the circle in the four cross directions (up, down, left, right) of the boring die hole, ensuring the left and right readings are 0mm to 0mm. Move the machine tool along the Y-axis until the up and down readings are -Amm and +Bmm. At this point, the machine tool coordinates are (X0, Y(A+B) / 2). After removing the rotating connection assembly, perform precision boring on the pin holes corresponding to the boring die hole using the boring bar. During the calibration process, due to the boring bar's overhang length and the weight of the dial indicator, there is a certain dial indicator error at the front end of the boring bar, resulting in alignment errors and misalignment of the corresponding pin holes between parts, exceeding design requirements. During assembly, misalignment of the connecting holes was discovered, preventing the pin from being installed and necessitating individual fitting, which impacted quality and efficiency. Furthermore, inconsistent dimensions during fitting resulted in poor versatility and increased manufacturing costs. Therefore, determining the dial indicator readings for the boring bar before boring further improves accuracy, prevents misalignment between parts, enhances boring precision, improves assembly accuracy and efficiency, reduces the need for secondary fitting, and lowers processing costs.

[0015] Preferably, both the motor shaft and rotor of the water turbine are fitted with the boring template, and the pin holes distributed circumferentially on the motor shaft and rotor are machined using the same boring template. To ensure the coaxiality and perpendicularity of the motor shaft, main shaft, rotor, etc. in the water turbine, the same boring template is required for machining corresponding holes in pairs during the water turbine machining process.

[0016] Preferably, when machining several circumferentially distributed pin holes, the same boring bar is used for single-calibration and single-boring, with the dial indicator reading from step three applied. Step four is then repeated to machine the pin holes on the turbine's motor shaft or rotor. For example, when machining the rotor's holes, the rotor mates with the boring template, and the boring die holes on the template correspond to the rotor's holes. The same boring bar is used to perform precision boring on the circumferentially distributed holes on the rotor. Therefore, it is necessary to first confirm the dial indicator reading of the boring bar, and then apply that reading. By simply repeating step four, all holes can be sequentially calibrated and single-bored.

[0017] Preferably, after removing the rotating connection assembly in step four, verify the accuracy of the dial indicator reading: Increase the setting value on one side of the boring head of the boring bar, and re-bore the boring die hole; then install the rotating connection assembly with the dial indicator clamped on the boring bar, and measure the four vertical differences between the newly bored mark and the original boring die hole in the four cross directions (up, down, left, right). If the four vertical differences are consistent, the dial indicator reading is verified to be accurate. This step is used to check the accuracy of the dial indicator reading and can also be used for random sampling.

[0018] Therefore, the present invention has the following beneficial effects: The dial indicator can be positioned at the same location as the boring bar. When the boring bar performs secondary hole calibration on the boring die hole of the boring template, the position of the dial indicator is consistent with the previous installation position and is firmly installed, preventing damage to the boring bar or problems with forceful suction. This improves the service life of the boring bar. The rotating connector is compatible with boring bars of different specifications. The threaded hole on the boring bar is an imperial threaded hole, therefore the rotating connector in this solution can be universally used on boring bars of different specifications, unaffected by the end face area of ​​the boring bar or the boring head. This further improves the accuracy of boring, prevents misalignment between parts during assembly, further improves the precision of boring, improves assembly accuracy and efficiency, reduces secondary single-assembly machining, and lowers processing costs. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a rotating connection component in Embodiment 1 of the present invention.

[0020] Figure 2 This is a schematic diagram of a structure according to Embodiment 1 of the present invention.

[0021] Figure 3 This is a schematic diagram of a structure according to Embodiment 2 of the present invention.

[0022] As shown in the picture: Boring tool holder 1, boring tool head 1.1 Percentage Table 2 Rotary connecting component 3 Mounting base 3.1, connecting part 3.1.1, abutting part 3.1.2, First link 3.2, second link 3.3, First rotating component 3.4, first U-shaped clamping component 3.4.1, first locking bolt 3.4.2, guide block 3.4.3, Second rotating component 3.5, second U-shaped clamping component 3.5.1, second locking bolt 3.5.2, fixing block 3.5.3, Screw 4 Boring template 5, boring die hole 5.1. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0024] Example 1, as Figure 1 , Figure 2 The device shown is a hole calibration device for precision boring of a large water turbine, including a boring bar 1 with a threaded hole, and a dial indicator 2. The dial indicator 2 is rotatably mounted on the front end of the boring bar 1 via a rotating connection assembly 3. The rotating connection assembly 3 includes a mounting base 3.1, which is locked onto the threaded hole of the boring bar 1 by screws 4. The above embodiment describes a hole-calibrating device for precision boring of large water turbines. A dial indicator 2 is mounted via a rotating connecting assembly 3. The boring bar 1 has a threaded hole (inch gauge). The mounting base 3.1 of the rotating connecting assembly 3 has a fixing hole that mates with the threaded hole. A screw 4 passes through the fixing hole of the mounting base 3.1 and is threadedly locked to the threaded hole, ensuring that the dial indicator 2 is positioned at the same location as the boring bar 1. When the boring bar 1 performs secondary hole calibration on the boring die hole 5.1 of the boring template 5, the position of the dial indicator 2 is consistent with its previous installation position and is securely installed, preventing damage to the boring bar 1 or damage from forceful adhesion. This improves the service life of the boring bar 1. It also solves the problem of inconsistent positioning of the dial indicator 2 during secondary hole calibration in existing large water turbine precision boring processes, where the dial indicator 2 is magnetically attached to the boring bar 1, leading to calibration errors and misalignment of connecting holes during turbine assembly.

[0025] Example 2, as Figure 1 , Figure 2 The device shown is a hole calibration device for precision boring of a large water turbine, including a boring bar 1 with a threaded hole, and a dial indicator 2. The dial indicator 2 is rotatably mounted on the front end of the boring bar 1 via a rotating connection assembly 3. The rotating connection assembly 3 includes a mounting base 3.1, which is locked onto the threaded hole of the boring bar 1 by screws 4.

[0026] The above embodiment describes a hole-calibrating device for precision boring of a large hydraulic turbine. A dial indicator 2 is mounted via a rotating connecting assembly 3. The boring bar 1 has a threaded hole (inch gauge). The mounting base 3.1 of the rotating connecting assembly 3 has a fixing hole that mates with the threaded hole. A screw 4 passes through the fixing hole of the mounting base 3.1 and is threadedly locked into the threaded hole. This ensures that the dial indicator 2 is positioned at the same location as the boring bar 1. When the boring bar 1 performs secondary hole calibration on the boring die hole 5.1 of the boring template 5, the position of the dial indicator 2 is consistent with its previous installation position and is securely installed, preventing damage to the boring bar 1 or problems with forced suction. This improves the service life of the boring bar 1.

[0027] Furthermore, such as Figure 1 , Figure 2As shown, the mounting base 3.1 includes a connecting part 3.1.1 and an abutting part 3.1.2. One end of the connecting part 3.1.1 is fixedly connected to the outer wall of the boring bar 1 by screws 4, and the other end is connected to the abutting part 3.1.2. The connecting part 3.1.1 is located on the side wall of the boring bar 1, and the abutting part 3.1.2 is located on the front end face of the boring bar 1. The connecting part 3.1.1 is distributed along the central axis of the boring bar 1, and the abutting part 3.1.2 is arranged parallel to the front end face of the boring bar 1. The connecting part 3.1.1 and the abutting part 3.1.2 form an L-shaped structure. The abutting part 3.1.2 is further optimized by providing a rubber pad on the side of the abutting part 3.1.2 facing the end face of the boring bar 1 to prevent the abutting part 3.1.2 from bumping or damaging the boring bar 1.

[0028] Specifically, such as Figure 1 , Figure 2 As shown, the rotating connection assembly 3 also includes a first connecting rod 3.2 and a second connecting rod. The rear end of the first connecting rod 3.2 is fixed on the mounting base 3.1, and the front end of the first connecting rod 3.2 is rotatably connected to the second connecting rod through a first rotating component. The dial indicator 2 is rotatably connected to the front end of the second connecting rod through a second rotating component 3.5. The central axis of the first connecting rod 3.2 coincides with or is parallel to the central axis of the boring bar 1. The central axis of the first connecting rod 3.2 coincides with or is parallel to the central axis of the boring bar 1, which serves to support the dial indicator 2. The first connecting rod 3.2 and the second connecting rod are rotatably connected through the first rotating component, and the dial indicator 2 and the second connecting rod are rotatably connected through the second rotating component 3.5, allowing the dial indicator 2 to rotate in various directions, realizing multi-directional measurements such as axial and radial measurements. This makes the hole calibration device in this solution adaptable to motor shafts, main shafts, rotors, etc. of different specifications of water turbines, and applicable to boring templates 5 of different specifications, thus having a wider range of applications.

[0029] In this embodiment, the boring bar 1 is provided with a boring head 1.1, and the bolt hole is located at a 45-degree angle to the connection of the boring head 1.1. The rotating connecting assembly 3 and the boring head 1.1 of the boring bar 1 do not affect each other. Compared with the magnetic base, the rotating connecting component in this solution is adaptable to boring bars 1 of different specifications. The threaded hole on the boring bar 1 is an imperial threaded hole. Therefore, the rotating connecting component in this solution can be universally used on boring bars 1 of different specifications, and is not affected by the end face area of ​​the boring bar 1 or the boring head 1.1.

[0030] Furthermore, such as Figure 1 , Figure 2As shown, the first rotating component includes a first U-shaped clamping member 3.4.1 sleeved on the first connecting rod 3.2 and a first locking bolt 3.4.2 locking the first U-shaped clamping member 3.4.1. A guide block 3.4.3 is provided on the outer side of the first U-shaped clamping member 3.4.1. The second connecting rod passes through and slides within the guide block 3.4.3. The first locking bolt 3.4.2 passes through the first U-shaped clamping member and is threadedly tightened to the guide block 3.4.3, abutting against the side wall of the second connecting rod. The first connecting rod 3.2 is slidably disposed within the first U-shaped clamping member. The clamping member locks the first connecting rod 3.2 through the first locking bolt 3.4.2. The first locking bolt 3.4.2 simultaneously locks the second connecting rod while locking the first connecting rod 3.2, thus fixing the first connecting rod 3.2 and the second connecting rod at the desired angle. The first connecting rod 3.2 and the second connecting rod adjust the angle and total length through the first connecting piece. The rotating connecting piece in this solution is compatible with boring bar 1 of different specifications. The threaded hole on the boring bar 1 is an imperial threaded hole. Therefore, the rotating connecting piece in this solution can be universally used on boring bar 1 of different specifications and is compatible with boring template 5 of different specifications.

[0031] The second rotating component 3.5 includes a second U-shaped clamping component 3.5.1 sleeved on the sleeve of the dial indicator 2 and a second locking bolt 3.5.2 locking the second U-shaped clamping component 3.5.1. A fixing block 3.5.3 is provided on the outer side of the second U-shaped clamping component 3.5.1. The second locking bolt 3.5.2 passes through the second U-shaped clamping component 3.5.1 and is threadedly locked to the fixing block 3.5.3. The fixing block 3.5.3 is located at the front end of the second connecting rod. The second rotating component 3.5 facilitates the rotation of the dial indicator 2. The second U-shaped clamping component 3.5.1 is used to clamp the dial indicator 2 onto the second U-shaped clamping component 3.5.1. The second U-shaped clamping component 3.5.1 is fixed to the front end of the second connecting rod by the fixing block 3.5.3.

[0032] The present invention has the following beneficial effects: The dial indicator 2 can be positioned in the same location as the boring bar 1. When the boring bar 1 performs secondary hole calibration on the boring die hole 5.1 of the boring template 5, the position of the dial indicator 2 is consistent with its previous installation position and is firmly installed, preventing damage to the boring bar 1 or problems with forced adhesion. This improves the service life of the boring bar 1. The rotating connector is compatible with boring bars 1 of different specifications. The threaded hole on the boring bar 1 is an imperial threaded hole; therefore, the rotating connector in this solution can be universally used on boring bars 1 of different specifications, unaffected by the end face area of ​​the boring bar 1 or the boring head 1.1. This solves the problem that in existing large-scale turbine precision boring and calibration, the dial indicator 2 is magnetically attached to the boring bar 1, which cannot guarantee the consistency of the dial indicator 2's position during secondary hole calibration, causing calibration errors and resulting in misalignment of the connecting holes during turbine assembly.

[0033] Example 3, as Figure 1 , Figure 2 , Figure 3 As shown, the operation method of a hole-calibrating device for precision boring of a large water turbine using any of the above-mentioned methods includes a boring template 5, which has boring holes 5.1, and includes the following steps in sequence: Step 1: Before precision boring any pin hole, select the corresponding boring die hole 5.1 on the boring template 5, and align it with the inner circle of the boring die hole 5.1 as the reference. Fix one end of the rotating connection component 3 to the threaded hole of the boring bar 1 with screw 4, and set up the dial indicator 2 on the other end. Connect the dial indicator 2 to the boring die hole 5.1. Step 2: Mark four cross directions (up, down, left, right) on the outer sidewall of the boring die hole 5.1. Rotate dial indicator 2 along the four cross directions of the boring die hole 5.1 using the boring bar 1. At this time, the readings of dial indicator 2 in the four cross directions of the boring die hole 5.1 should all be 0mm. Then, set the machine tool coordinates to zero (X0, Y0), remove the rotating connection assembly 3, and keep dial indicator 2 clamped on the rotating connection assembly 3. Use the boring bar 1 to perform a trial boring of the boring die hole 5.1 with the minimum amount of boring. The boring marks will be left on the inner wall of the boring die hole 5.1. Step 3: Reinstall the rotating connection assembly 3 and dial indicator 2 at the front end of the boring bar 1, and re-round the mark bored in Step 2. Rotate the dial indicator 2 through the boring bar 1 to calibrate the roundness in the four cross directions of the boring die hole 5.1. When the actual readings of the left and right are 0mm to 0mm, the actual readings of the up and down are -Amm and +Bmm. The difference between the up and down values ​​at this time is the dial indicator reading of the boring bar 1. Record the dial indicator reading data. Step 4: Move the boring bar 1 a certain distance along the Z-axis of the machine tool spindle towards the depth of the boring die hole 5.1, avoiding the test boring marks from Step 2. Align it according to the inner circle of the original boring die hole 5.1. Rotate the dial indicator 2 on the boring bar 1 to calibrate the circle in the four cross directions of the boring die hole 5.1, so that the left and right readings of the dial indicator 2 are 0mm to 0mm. Move the Y-axis of the machine tool until the up and down readings are -Amm and +Bmm. At this time, the machine tool coordinates are (X0, Y(A+B) / 2). After removing the rotating connection assembly 3, perform boring and finishing machining on the pin hole corresponding to the boring die hole 5.1 using the boring bar 1.

[0034] Currently, the motor shafts and rotors in large hydroelectric units are mostly machined separately due to their large diameter and tonnage. However, ensuring concentricity is difficult, causing challenges in later assembly. Therefore, boring templates are used for machining the motor shafts and main shafts to ensure boring accuracy. Typically, the flange holes connecting the two shafts are over 600mm long, and the design clearance between the pin and the hole is within 0.03mm-0.04mm. Therefore, ensuring coaxiality and perpendicularity is very difficult. During the boring process, the long overhang of the boring bar, coupled with the gravity exerted by the dial indicator and other components, causes misalignment errors exceeding design requirements.

[0035] During the hole alignment process, due to factors such as the overhang length of the boring bar 1 and the weight of the dial indicator 2, there is a certain dial indicator error at the front end of the boring bar 1. This causes alignment errors in the boring bar 1, resulting in misalignment of the corresponding pin holes between parts, exceeding design requirements. During assembly, misalignment of the connecting holes was discovered, causing pins to be unable to be installed, requiring separate fitting, affecting quality and efficiency. Inconsistent fitting dimensions also lead to poor versatility and increased manufacturing costs. Therefore, determining the dial indicator reading of the boring bar 1 before boring further improves boring accuracy, prevents misalignment between parts, improves boring precision, enhances assembly accuracy and efficiency, reduces secondary fitting, and lowers processing costs.

[0036] The dial indicator 2 is rotatably mounted on the front end of the boring bar 1 via a rotating connecting assembly 3. The rotating connecting assembly 3 includes a mounting base 3.1, which is locked onto the threaded hole of the boring bar 1 by screws 4. This solution provides a hole calibration device for precision boring of large water turbines. The dial indicator 2 is mounted via the rotating connecting assembly 3. The boring bar 1 has an imperial threaded hole, and the mounting base 3.1 of the rotating connecting assembly 3 has a fixing hole that mates with the threaded hole. The screws 4 pass through the fixing hole of the mounting base 3.1 and are threadedly locked into the threaded hole, ensuring that the dial indicator 2 is positioned at the same location as the boring bar 1. When the boring bar 1 performs secondary hole calibration on the boring die hole 5.1 of the boring template 5, the position of the dial indicator 2 is consistent with its previous installation position and is securely installed, preventing damage to the boring bar 1 or problems with forced suction. This improves the service life of the boring bar 1.

[0037] Specifically, both the motor shaft and rotor of the water turbine are fitted with the boring plate 5, and the pin holes distributed in a circle on the motor shaft and rotor are machined using the same boring plate 5. In order to ensure the coaxiality and perpendicularity of the motor shaft, main shaft, rotor, etc. in the water turbine, the same boring plate 5 is required for machining corresponding holes in pairs during the water turbine machining process.

[0038] Specifically, when machining several circumferentially distributed pin holes, the same boring bar 1 is used for single-calibration and single-boring, with the dial indicator measurement from step three being applied. Step four is repeated to machine the pin holes on the turbine motor shaft or rotor. For example, when machining the rotor holes, the rotor mates with the boring template 5, and the boring die hole 5.1 on the boring template 5 corresponds to the rotor holes. The same boring bar 1 is used to perform precision boring on the circumferentially distributed holes on the rotor. Therefore, it is necessary to first confirm the dial indicator measurement of the boring bar 1, and then apply the dial indicator measurement. Only step four needs to be repeated to complete the sequential single-calibration and single-boring of all holes.

[0039] Furthermore, after removing the rotating connecting assembly 3 in step four, verify the accuracy of the dial indicator reading: Increase the setting value on one side of the boring head 1.1 of the boring bar 1, and re-bort the die hole 5.1; then install the rotating connecting assembly 3 with the dial indicator 2 clamped on the boring bar 1, and measure the four vertical differences between the newly bored mark and the original die hole 5.1 in the four cross directions (up, down, left, right). If the four vertical differences are consistent, the dial indicator reading is verified to be accurate. This step is used to check the accuracy of the dial indicator reading and can also be used for spot checks.

[0040] The present invention has the following beneficial effects: The dial indicator 2 can be positioned in the same location as the boring bar 1. When the boring bar 1 performs secondary hole calibration on the boring die hole 5.1 of the boring template 5, the position of the dial indicator 2 is consistent with its previous installation position and is firmly installed, preventing damage or forceful suction to the boring bar 1. This improves the service life of the boring bar 1. The rotating connector is compatible with boring bars 1 of different specifications. The threaded hole on the boring bar 1 is an imperial threaded hole; therefore, the rotating connector in this solution can be universally used on boring bars 1 of different specifications, unaffected by the end face area of ​​the boring bar 1 or the boring head 1.1. This further improves the accuracy of boring, prevents misalignment between parts during assembly, further improves the precision of boring, increases assembly accuracy and efficiency, reduces secondary single-assembly machining, and lowers processing costs.

[0041] Example of this scheme: Before the pin holes distributed circumferentially on the precision boring motor shaft, select any corresponding boring die hole 5.1 on the boring template 5. Use the inner circle of the boring die hole 5.1 as a reference for alignment. Fix one end of the rotating connecting assembly 3 to the threaded hole of the boring bar 1 with screws 4, and mount a dial indicator 2 on the other end. Align the dial indicator 2 with the boring die hole 5.1. Mark four cross directions (up, down, left, right) on the outer sidewall of the opening of the boring die hole 5.1. Rotate the boring bar 1 to mark the four cross directions (up, down, left, right) of the boring die hole 5.1. The dial indicator 2 is adjusted to 0mm in all four directions (up, down, left, right) of the boring die hole 5.1. The machine tool coordinates are then zeroed (X0, Y0). The rotating connection assembly 3 is removed, but the dial indicator 2 remains clamped to it. The boring bar 1 is then used to test-bor the boring die hole 5.1 with the minimum allowable boring, leaving an imprint on the inner wall of the hole. The rotating connection assembly 3 and the dial indicator 2 are then reinstalled on the front end of the boring bar 1, and the newly bored imprint is re-rounded. The boring bar 1 is rotated with dial indicator 2 to calibrate the roundness of the boring die hole 5.1 in four directions: up, down, left, and right. When the actual readings for left and right are 0mm to 0mm, the actual readings for up and down are -0.04mm and +0.06mm, respectively. The difference between these values ​​is the dial indicator reading of the boring bar 1, and this reading is recorded. The boring bar 1 is then moved 10mm along the Z-axis of the machine tool spindle towards the depth of the boring die hole 5.1, avoiding the marks left by the test boring, and aligned with the original inner circle of the boring die hole 5.1. The boring bar 1 rotates the dial indicator 2 to calibrate the roundness of the boring die hole 5.1 in four cross directions (up, down, left, and right), so that the left and right readings of the dial indicator 2 are 0mm and 0mm respectively, and the Y-axis of the machine tool is moved to achieve the up and down readings of -0.04mm and +0.06mm. At this time, the machine tool coordinates are (X0, Y0.05). After removing the rotating connection assembly 3, the pin hole corresponding to the boring die hole 5.1 is bored and finished using the boring bar 1. The same dial indicator measurement is used for other pin holes distributed in a circle. This process is repeated for each individual calibration and boring operation. In this invention, the dial indicator 2 can be set in the same position as the boring bar 1. When the boring bar 1 performs a secondary calibration of the boring die hole 5.1 of the boring template 5, the position of the dial indicator 2 is consistent with the previous installation position and is firmly installed, preventing damage to the boring bar 1 or problems with forced suction. This design improves the service life of the boring bar 1. The rotating connector is compatible with boring bars 1 of different specifications. The threaded holes on the boring bar 1 are imperial threaded holes. Therefore, the rotating connector in this design can be used on boring bars 1 of different specifications, unaffected by the end face area of ​​the boring bar 1 or the boring head 1.1. It also solves the problem that in existing large-scale turbine precision boring and calibration processes, the dial indicator 2, attached to the boring bar 1 by a magnetic base, cannot guarantee the consistency of the dial indicator 2's position during secondary calibration, causing calibration errors and resulting in misalignment of the connecting holes during turbine assembly.

[0042] The specific embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the invention. All equivalent variations made in accordance with the shape and structure of the present invention should be included within the scope of protection of the present invention.

Claims

1. An operating method for a hole-calibrating device used for precision boring of large water turbines, characterized in that, Including a boring template with boring holes, the process includes the following steps: Step 1: Before precision boring any pin hole, select the boring die hole on the boring template, use the inner circle of the boring die hole as a reference for alignment, fix one end of the rotating connection component to the threaded hole of the boring bar with screws, and set up a dial indicator on the other end, with the dial indicator engaging with the boring die hole; Step 2: Mark four cross directions (up, down, left, right) on the outer wall of the boring die hole. Rotate the dial indicator on the four cross directions of the boring die hole using the boring bar. At this time, the dial indicator readings and pressure gauge readings should all be 0mm. Then, set the machine tool coordinates to zero (X0, Y0), remove the rotating connection assembly, and test bore the boring die hole with the minimum amount of boring. An imprint will be left on the inner wall of the boring die hole. Step 3: Reinstall the rotating connection assembly of the clamping dial indicator onto the front end of the boring bar, and re-round the mark bored in Step 2. Rotate the dial indicator on the boring bar to calibrate the roundness in the four cross directions of the boring die hole. When the actual reading on the left and right is 0mm to 0mm, the actual readings on the top and bottom are -Amm and +Bmm. The difference between the top and bottom is the dial indicator setting on the boring bar. Record this dial indicator setting data. Step 4: Move the boring bar a certain distance along the Z-axis of the machine tool spindle towards the depth of the boring die hole, avoiding the test boring marks from Step 2. Align the hole with the original inner circle of the boring die hole. Rotate the dial indicator on the boring bar to calibrate the hole in the four cross directions (up, down, left, right) until the dial indicator readings are 0mm to 0mm. Move the Y-axis of the machine tool until the readings are -Amm and +Bmm. At this point, the machine tool coordinates are (X0, Y(A+B) / 2). After removing the rotating connection assembly, perform precision boring on the corresponding pin hole of the boring die hole using the boring bar.

2. The operating method of the hole-calibrating device for precision boring of a large water turbine according to claim 1, characterized in that, The hole-calibrating device includes a boring bar with a threaded hole; it also includes a dial indicator, which is rotatably mounted on the front end of the boring bar via a rotating connection assembly, the rotating connection assembly including a mounting base, which is locked onto the threaded hole of the boring bar by screws.

3. The operating method of the hole-calibrating device for precision boring of a large water turbine according to claim 2, characterized in that, The mounting base includes a connecting part and an abutting part. One end of the connecting part is fixedly connected to the outer wall of the boring bar by a screw, and the other end is connected to the abutting part. The connecting part is located on the side wall of the boring bar, and the abutting part is located on the front end face of the boring bar.

4. The operating method of the hole-calibrating device for precision boring of a large water turbine according to claim 2 or 3, characterized in that, The rotating connection assembly further includes a first connecting rod and a second connecting rod. The rear end of the first connecting rod is fixed on the mounting base, and the front end of the first connecting rod is rotatably connected to the second connecting rod through a first rotating component. The dial indicator is rotatably connected to the front end of the second connecting rod through a second rotating component. The central axis of the first connecting rod coincides with or is parallel to the central axis of the boring bar.

5. The operating method of the hole-calibrating device for precision boring of a large water turbine according to claim 2 or 3, characterized in that, The boring bar is equipped with a boring head, and the threaded hole is located at a 45-degree angle to the connection of the boring head.

6. The operating method of the hole-calibrating device for precision boring of a large water turbine according to claim 4, characterized in that, The first rotating component includes a first U-shaped clamping component sleeved on the first connecting rod and a first locking bolt for locking the first U-shaped clamping component. A guide block is provided on the outer side of the first U-shaped clamping component. The second connecting rod passes through and is slidably disposed in the guide block. The first locking bolt passes through the first U-shaped clamping component, is threadedly tightened with the guide block, and abuts against the side wall of the second connecting rod.

7. The operating method of the hole-calibrating device for precision boring of a large water turbine according to claim 6, characterized in that, The second rotating component includes a second U-shaped clamping component sleeved on the sleeve of the dial indicator and a second locking bolt for locking the second U-shaped clamping component. A fixing block is provided on the outer side of the second U-shaped clamping component. The second locking bolt passes through the second U-shaped clamping component and is threadedly locked to the fixing block. The fixing block is located at the front end of the second connecting rod.

8. The operating method of the hole-calibrating device for precision boring of a large water turbine according to claim 1, characterized in that, The motor shaft and rotor of the water turbine are both fitted with the boring template, and the same boring template is used to process the circumferentially distributed pin holes on the motor shaft and rotor.

9. The operating method of the hole-calibrating device for precision boring of a large water turbine according to claim 8, characterized in that, When machining several circumferentially distributed pin holes, the same boring bar is used for single-calibration and single-boring, and the dial indicator measurement in step three is used. Step four is repeated to machine the pin holes on the motor shaft or the rotor of the water turbine.

10. The operating method of the hole-calibrating device for precision boring of a large water turbine according to claim 1, characterized in that, After removing the rotating connection assembly in step four, verify the accuracy of the dial indicator reading: increase the setting value on one side of the boring head of the boring bar and re-boring the boring die hole; then install the rotating connection assembly with the dial indicator clamped on the boring bar, and measure the four vertical differences between the newly bored mark and the original boring die hole in the four cross directions (up, down, left, and right). If the four vertical differences are consistent, the dial indicator reading is verified to be accurate.

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