Method for determining machining size of copper tile on water turbine

Abstract

The invention provides a method for determining the machining size of a copper tile on a water turbine. The method comprises the steps that firstly, a shell is placed and fixed; 2, measuring the size of the accommodating chamber: selecting a measurement group along the circumferential direction, and calculating a measured average value X; 3, the outer diameter H2 of the copper tile needing to be machined is determined, and the outer diameter H2 of the copper tile needing to be machined is calculated according to the average value X in the step 2 and the preset interference fit amount r; 4, the inner diameter H3 of the copper tile is determined, specifically, the outer cylindrical surface of the pivot is measured, and the inner diameter H3 of the copper tile needing to be machined is calculated according to the preset design gap amount s; therefore, according to the outer diameter H2 and the inner diameter H3 of the copper tile obtained in the step 3 and the step 4, the size needing to be machined of the copper tile is obtained. In this way, the actual machining size of the copper tile is determined according to the size of the shell and the size of the pivot which are matched with the copper tile. Therefore, the matching precision can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water turbine copper shoe processing, and particularly relates to a method for determining the processing size of a copper shoe on a water turbine. BACKGROUND

[0002] In the operation process of the water turbine set, the pivot forms a matching structure with the shell through the copper shoe. The copper shoe forms an interference fit with the shell on the radial outer side to ensure reliable fixation; and forms a clearance fit with the pivot on the radial inner side to ensure smooth rotation of the pivot.

[0003] However, the existing processing method mainly relies on experience or only uses the nominal size on the design drawing for processing, often ignoring the error factors existing in the actual measurement data. For example, if the diameter of the shell accommodating chamber has a measurement error, and no correction is made, the interference amount will be insufficient or too large; if the deviation of the pivot outer diameter in the processing and measurement process is not taken into account, the clearance fit precision will be insufficient; if the copper shoe outer diameter and inner diameter processing are not dynamically corrected based on the actual measurement data, multiple trial fittings will be required, increasing the maintenance cycle and cost. SUMMARY

[0004] In view of the deficiencies in the prior art, the present application provides a method for determining the processing size of a copper shoe on a water turbine. To achieve the above object, the present application adopts the following technical solutions: A method for determining the processing size of a copper shoe on a water turbine, the water turbine comprising: a shell, the shell being provided with an accommodating chamber configured to allow the copper shoe to be placed therein and fixed together with the radial outer side of the copper shoe; a pivot configured to be inserted into the copper shoe and fixed together with the radial inner side of the copper shoe; The method comprises the following steps: Step 1: placing and fixing the shell: place the shell on a horizontal surface, adjust it to be horizontal using a level, and then fix it to the horizontal surface using a clamp; Step 2: measuring the size of the accommodating chamber: on the inner wall of the accommodating chamber, evenly select at least four measurement groups in the circumferential direction, and measure multiple times at different depths in the axial direction of the accommodating chamber for each measurement group, to obtain multiple diameter measurement values of the accommodating chamber, and calculate the average value X of all diameter measurement values; Step 3: determining the outer diameter H2 of the copper shoe to be processed: according to the average value X obtained in step 2 and the predetermined design interference fit amount r, calculate the outer diameter H2 of the copper shoe to be processed by the formula H2=X+r; Step four, determining the inner diameter H3 of the copper shoe: using the outer diameter micrometer to measure the outer cylindrical surface of the pivot at multiple points to obtain an average value d; according to the average value d and the predetermined design gap s, the inner diameter H3 of the copper shoe to be machined is calculated by the formula H3=d+s; Thus, the size of the copper shoe to be machined is obtained according to the outer diameter H2 and the inner diameter H3 obtained in steps three and four.

[0005] Further, the measurement groups are arranged into four groups, and each group of measurement points is distributed at an interval of 90 degrees in the circumferential direction.

[0006] Further, each group of measurement groups is measured at the upper, middle and lower parts in the axial direction of the accommodating chamber, and a total of twelve measurement values are obtained.

[0007] Further, the design interference fit amount r is a fixed value or a numerical range determined according to the design drawings of the water turbine.

[0008] Further, the numerical range of the design interference fit amount r is obtained by subtracting the lower limit value of the design size of the inner diameter of the accommodating chamber from the upper limit value of the design size of the outer diameter of the copper shoe, to obtain the maximum design interference amount rmax. The minimum design interference amount rmin is obtained by subtracting the upper limit value of the design size of the inner diameter of the accommodating chamber from the lower limit value of the design size of the outer diameter of the copper shoe.

[0009] Further, the design gap amount s is a fixed value or a numerical range determined according to the design drawings of the water turbine.

[0010] Further, the numerical range of the design gap amount s is obtained by subtracting the lower limit value of the design size of the outer diameter of the pivot from the upper limit value of the design size of the inner diameter of the copper shoe, to obtain the maximum design gap amount smax; and the minimum design gap amount smin is obtained by subtracting the upper limit value of the design size of the outer diameter of the pivot from the lower limit value of the design size of the inner diameter of the copper shoe.

[0011] Further, in step three, when the design interference fit amount r is a numerical range [rmin, rmax], the machining range of the outer diameter H2 of the copper shoe is [X+rmin, X+rmax]; and in step four, when the design gap amount s is a numerical range [smin, smax], the machining range of the inner diameter H3 of the copper shoe is [d+smin, d+smax].

[0012] Further, in step two, an inner diameter micrometer or a three-dimensional scale is used for measurement; and in step four, an outer diameter micrometer or a laser range finder is used for measurement of the pivot.

[0013] Further, after obtaining the size of the copper shoe to be machined, the sizes H2 and H3 are input into a numerical control machine tool, and the machining of the copper shoe blank is automatically completed by the numerical control machine tool.

[0014] Compared with the prior art, the present application has the following beneficial effects: The method for determining the processing size of the copper tile comprises the following steps: step one, placing and fixing the shell: placing the shell on a horizontal surface, adjusting it to be horizontal using a level, and then fixing it to the horizontal surface using a clamp; step two, measuring the size of the accommodating chamber: selecting at least four measurement groups uniformly along the circumferential direction on the inner wall of the accommodating chamber, measuring multiple times at different depths of the accommodating chamber in the axial direction for each measurement group, obtaining multiple diameter measurement values of the accommodating chamber, and calculating the average value X of all the diameter measurement values; step three, determining the outer diameter H2 of the copper tile to be processed: calculating the outer diameter H2 of the copper tile to be processed by the formula H2=X+r according to the average value X obtained in step two and a predetermined design interference fit amount r; step four, determining the inner diameter H3 of the copper tile: using an outer diameter micrometer to measure multiple points on the outer cylindrical surface of the pivot, obtaining the average value d; calculating the inner diameter H3 of the copper tile to be processed by the formula H3=d+s according to the average value d and a predetermined design gap amount s; thereby, the size of the copper tile to be processed is obtained according to the outer diameter H2 and the inner diameter H3 of the copper tile obtained in steps three and four. In this way, the actual processing size of the copper tile is determined by the sizes of the shell and the pivot that cooperate with the copper tile. Therefore, the size of the processed copper tile can further fit the shell and the pivot, thereby improving the fitting accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0015] The present application will be further described below in conjunction with the drawings and examples: Figure 1 It is a schematic diagram of the overall structure of the water turbine of the embodiment of the present application; Figure 2 It is a schematic diagram of the overall structure of the shell of the embodiment of the present application; Figure 3 It is a schematic diagram of the overall structure of the copper tile of the embodiment of the present application.

[0016] In the above drawings: water turbine 10, copper tile 100, shell 101, accommodating chamber 1011, pivot 102. DETAILED DESCRIPTION

[0017] The technical solutions in the present application will be further described below in conjunction with the drawings and examples.

[0018] In order to better understand the purpose, structure and function of the present application, the method for determining the processing size of the copper tile on the water turbine will be further described in detail below in conjunction with the drawings.

[0019] As Figure 1As shown, the turbine 10 typically includes a housing 101, on which a receiving chamber 1011 is provided. The receiving chamber 1011 is configured to accommodate copper tiles 100 and is fixed to the radially outer side of the copper tiles 100. The turbine 10 also includes a pivot 102. The pivot 102 is configured to pass through the copper tiles 100 and is fixed to the radially inner side of the copper tiles 100.

[0020] It should be noted that the radially outer side of the copper tile 100 is interference-fitted with the housing 101, while the radially inner side of the copper tile 100 is clearance-fitted with the pivot 102. This allows the pivot 102 to rotate stably along the copper tile 100, thereby enabling the operation of the turbine 10. Furthermore, the structure of the turbine 10 and the fitting relationships between its various components are well known to those skilled in the art, and therefore will not be described further here.

[0021] Figure 1 The illustration schematically shows a method for determining the machining dimensions of copper tiles on a water turbine according to the present invention. In such a way... Figure 1 In the illustrated embodiment, the method for determining the machining dimensions of the copper tiles on the turbine includes the following steps. It should be noted that the following steps are based on the machining of a 1400mm copper tile as an example.

[0022] Step 1: Placement and Fixing of the Housing Technical considerations: The core of this step is to establish a stable and accurate measurement benchmark. The housing 101 is a large cast and welded component; deformation caused by its own weight and non-level placement will significantly affect the accuracy of measuring the roundness and centerline of the inner hole.

[0023] Lifting and Positioning: Using a workshop overhead crane and a dedicated lifting beam, the shell 101 was smoothly lifted onto a solid concrete foundation platform using a four-point lifting method. Ensure its axis is approximately perpendicular to the horizontal plane.

[0024] Precise leveling: On the precision reference surface machined at the upper end of housing 101, measurements are taken using an electronic level (accuracy up to 0.01 mm / m). Initial adjustment is first performed on two mutually perpendicular centerlines: 0° (+Y direction) and 90° (+X direction). Fine adjustment is then performed in four directions: 0°, 90°, 180°, and 270°. By fine-tuning the adjustable shims placed under the flange of housing 101, the levelness error in each direction is controlled within ≤0.03 mm / m. This ensures that the deviation between the inner hole centerline measured subsequently and the theoretical centerline is minimized.

[0025] Reliable fixing: After leveling, immediately install multiple sets of hydraulic locking clamps symmetrically on the flange of housing 101 to firmly press it onto the platform, eliminating any potential minor displacement or vibration and providing a stable environment for precision measurement.

[0026] The second step is to measure the dimensions of the receiving chamber. Technical considerations: Geometric errors (such as roundness and cylindricity) in large internal holes are key factors affecting the uniformity of interference fits. Multi-point, multi-section measurements aim to "reproduce" the true three-dimensional morphology of the hole.

[0027] Survey planning and benchmarking: such as Figure 1 As shown, four sets of measurement groups are uniformly defined along the circumference on the inner wall of the receiving chamber (1011): group A (0°), group B (90°), group C (180°), and group D (270°). For precise positioning, an optical projector or a piano horn can be used with a dial indicator to draw a crosshair on the end face as an angular reference.

[0028] Measurement tools and procedures: Use an electronic inside micrometer with a telescopic rod (0.001 mm resolution) or a laser tracker for measurement. Before measurement, calibrate the measuring instrument using a standard ring gauge.

[0029] Axial measurement points: Three sections are strictly defined along the axis of each measurement group: Section I (upper part): 100mm from the end face of the orifice.

[0030] Section II (middle): at 1 / 2 of the axial length of the chamber.

[0031] Section III (lower part): 100 mm from the bottom of the chamber.

[0032] Circumferential measurement: On each cross section, measure the dimensions in two mutually perpendicular diametrical directions (e.g., for group A 0°, measure the 0°–180° direction; for group B 90°, measure the 90°–270° direction). Measure each direction three times consecutively and take the average value to eliminate random errors.

[0033] Data recording, processing, and uncertainty analysis: Record all 4 groups × 3 sections × 2 directions = 24 measurements.

[0034] The arithmetic mean of all 24 measurements, X = 1450.015 mm, is calculated. This value represents the “average diameter” of the accommodating chamber (1011) in its current state.

[0035] Further analysis: The average diameter and roundness of each section, as well as the cylindricity of the whole hole, can be calculated respectively. For example, it is found that the average diameter of the middle section (II) is 0.008 mm smaller than that of the upper section (I), which indicates that the hole has a slight drum shape. This method effectively "averages" the complex geometric error by taking the total average X, providing a representative size for subsequent calculations.

[0036] Third step, determine the outer diameter H2 of the copper tile Technical considerations: The selection of the interference amount needs to balance the connection strength and assembly stress. The present invention dynamically combines the design intention (drawing tolerance) with the physical state (actual measured size).

[0037] Determination of the design interference fit amount r: According to the drawing, the chamber design size is φ1450 H7( +0.04 ), i.e. the range [1450.000, 1450.040] mm.

[0038] The copper tile outer diameter design size is φ1450.3s6( +0.08 ), φ1450.3s6( +0.043 ), i.e. the range [1450.343, 1450.368] mm.

[0039] According to the tolerance band calculation theory, the interference amount range: the maximum design interference amount rmax = the maximum value of the copper tile outer diameter - the minimum value of the chamber inner diameter = 1450.368 - 1450.000 = 0.368 mm, the minimum design interference amount rmin = the minimum value of the copper tile outer diameter - the maximum of the chamber inner diameter = 1450.343 - 1450.040 = 0.303 mm.

[0040] Conclusion: The range of the design interference fit amount r is [0.303, 0.368] mm. This range ensures the tightness and safety of the connection.

[0041] Calculation of the copper tile outer diameter H2: Apply the formula H2 = X + r.

[0042] The lower limit of the H2 processing range: H2min = 1450.015 + 0.303 = 1450.318 mm The upper limit of the H2 processing range: H2max = 1450.015 + 0.368 = 1450.383 mm Engineering decision: To obtain the most reliable interference fit and compensate for the slight shrinkage (expansion) effect of the inner hole after the copper tile is pressed in, this embodiment selects a value above the upper limit in the range for processing, and sets the target value of the copper tile outer diameter H2 = 1450.375 mm, with a tolerance band of ± 0.01 mm.

[0043] Fourth step, determine the inner diameter H3 of copper shoe Technical considerations: The gap amount needs to ensure good lubrication while limiting vibration and leakage. The actual size of the pivot is the dynamic reference.

[0044] Precision measurement of the outer diameter d of the pivot: A large digital outside micrometer is used to measure in a constant temperature workshop (20±1°C) to reduce the effect of thermal expansion.

[0045] On the effective fitting length of the pivot, 5 measurement sections are selected at equal intervals. At each section, rotate the pivot and measure at 0°, 72°, 144°, 216°, and 288° five circumferential positions.

[0046] Record all 25 data, eliminate one maximum and one minimum, take the arithmetic mean, get the actual average outer diameter d of the pivot (102) = 1399.992 mm. At the same time, calculate its cylindricity as 0.015 mm, within the allowable range.

[0047] Determination of the design gap amount s: Check the drawing: Pivot design size: φ1400 h6( 0 ), φ1400 h6( -0.022 ) i.e. range [1399.978, 1400.000] mm.

[0048] Copper shoe inner diameter design size: φ1400.2 H7( +0.0400 ), i.e. range [1400.200, 1400.240] mm.

[0049] Calculate the theoretical gap amount range: maximum design gap smax = copper shoe inner diameter maximum - pivot outer diameter minimum = 1400.240 - 1399.978 = 0.262 mm, minimum design gap amount smin = copper shoe inner diameter minimum - pivot outer diameter maximum = 1400.200 - 1400.000 = 0.200 mm Conclusion: The range of design gap amount s is [0.200, 0.262] mm. This range ensures the formation of sufficient lubricating oil film.

[0050] Calculation of copper shoe inner diameter H3: Apply formula H3 = d + s.

[0051] Lower limit of H3 machining range: H3min = 1399.992 + 0.200 = 1400.192 mm Upper limit of H3 machining range: H3max = 1399.992 + 0.262 = 1400.254 mm Engineering decision: considering the possible micro-shrinkage (experience value about 0.02mm) of the inner hole after the copper tile is pressed into the shell, in order to ensure the final gap, it is necessary to compensate in advance. Therefore, the target gap is set to the upper limit of the range, that is, the copper tile inner diameter target value H3=1400.245 mm, and the tolerance band is set to +0.015 / -0.000 mm (to ensure the minimum wall thickness).

[0052] Fifth step, automatic processing and assembly verification of copper tile Digital processing: H2=1450.375±0.01mm and H3=1400.245 +0.0150 mm as the final processing size, generate CAM processing program. Process the outer circle of the copper tile on the numerical control vertical lathe to the size, and then turn over to fine bore the inner hole. During processing, use the online measuring head for on-machine measurement, and real-time feedback compensation for tool wear.

[0053] Assembly verification: after processing, the copper tile is cooled and assembled in liquid nitrogen, and is successfully pressed into the shell 101 containing chamber. The final size of the copper tile inner hole after assembly is 1400.228mm. The actual fitting gap between the copper tile and the pivot (d=1399.992mm) is 0.236mm, which is perfectly within the design gap range [0.200, 0.262]mm.

[0054] Finally, it should be pointed out that the above examples are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the purpose and scope of the present application, and they should be covered in the scope of the claims of the present application.

Claims

1. A method for determining the machining size of a copper shoe on a hydraulic turbine (10), the hydraulic turbine (10) comprising: a housing (101) provided with a containing chamber (1011) configured to allow the copper shoe (100) to be contained and fixed to the radially outer side of the copper shoe (100); and a pivot shaft (102) configured to allow the copper shoe (100) to be penetrated and fixed to the radially inner side of the copper shoe (100), characterized in that the method comprises the following steps: Step 1, placing and fixing the housing (101): placing the housing (101) on a horizontal plane, adjusting it to be horizontal using a level, and then fixing it to the horizontal plane by using a clamp; Step 2, measuring the size of the containing chamber (1011): selecting at least four measurement groups uniformly in the circumferential direction on the inner wall of the containing chamber (1011), measuring multiple times at different axial depths of the containing chamber (1011) in each measurement group, obtaining multiple diameter measurement values of the containing chamber (1011), and calculating the average value X of all the diameter measurement values; Step 3, determining the outer diameter H2 of the copper shoe (100) to be machined: calculating the outer diameter H2 of the copper shoe (100) to be machined by the formula H2 = X + r according to the average value X obtained in Step 2 and a predetermined design interference fit amount r; Step 4, determining the inner diameter H3 of the copper shoe (100): measuring multiple points on the outer cylindrical surface of the pivot shaft (102) using an outer diameter micrometer to obtain an average value d; and calculating the inner diameter H3 of the copper shoe (100) to be machined by the formula H3 = d + s according to the average value d and a predetermined design gap amount s; thereby obtaining the size of the copper shoe to be machined according to the outer diameter H2 and the inner diameter H3 of the copper shoe obtained in Steps 3 and 4. The measurement groups are arranged in four groups, and the measurement points in each group are distributed at an interval of 90 degrees in the circumferential direction. Each measurement group measures at the upper, middle and lower parts of the axial direction of the containing chamber (1011), and a total of twelve measurement values are obtained. The design interference fit amount r is a fixed value or a numerical range determined according to the design drawings of the hydraulic turbine (10). The numerical range of the design interference fit amount r is obtained by subtracting the lower limit value of the design size of the inner diameter of the containing chamber (1011) from the upper limit value of the design size of the outer diameter of the copper shoe (100) to obtain the maximum design interference amount rmax. The minimum design interference amount rmin is obtained by subtracting the upper limit value of the design size of the inner diameter of the containing chamber (1011) from the lower limit value of the design size of the outer diameter of the copper shoe (100). The design gap amount s is a fixed value or a numerical range determined according to the design drawings of the hydraulic turbine (10). The numerical range of the design gap amount s is obtained by subtracting the lower limit value of the design size of the outer diameter of the pivot shaft (102) from the upper limit value of the design size of the inner diameter of the copper shoe (100) to obtain the maximum design gap amount smax; and the minimum design gap amount smin is obtained by subtracting the upper limit value of the design size of the outer diameter of the pivot shaft (102) from the lower limit value of the design size of the inner diameter of the copper shoe (100). ​ 2. The method of claim 1, wherein, ​ 3. The method of claim 2, wherein, ​ 4. The method of claim 1, wherein, ​ 5. The method of claim 4, wherein, ​ ​ 6. The method of claim 1, wherein, ​ 7. The method of determining the working size of the copper shoes on the hydraulic turbine according to claim 6, characterized in that, ​ 8. The method of claim 1, wherein, In step three, when the design interference fit amount r is a value range [rmin, rmax], the processing range of the outer diameter H2 of the copper tile (100) is [X+rmin, X+rmax]; in step four, when the design gap amount s is a value range [smin, smax], the processing range of the inner diameter H3 of the copper tile (100) is [d+smin, d+smax].

9. The method of determining the finished size of a copper shoe on a hydraulic turbine according to any one of claims 1 to 8, wherein, In step two, an inner diameter micrometer or a three-dimensional scale is used for measurement; in step four, an outer diameter micrometer or a laser range finder is used to measure the pivot shaft (102).

10. The method of determining the working size of the copper shoes on the hydraulic turbine according to claim 1, characterized in that, After obtaining the size of the copper tile to be processed, the sizes H2 and H3 are input into the numerical control machine tool, and the processing of the copper tile blank is automatically completed by the numerical control machine tool.

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