A machining method for the bottleneck-shaped inner hole of a half cylinder of a steam turbine outer cylinder

Abstract

A machining method for the bottleneck-shaped inner hole of a half cylinder of a steam turbine outer cylinder, belonging to the field of machining methods for the bearing inner hole of a steam turbine outer cylinder. The present invention aims to solve the problems of poor processability and high machining difficulty existing in the bottleneck-shaped inner hole of the half cylinder of the existing steam turbine outer cylinder. By adopting the method of split machining and appropriately adjusting the machining process, strictly controlling the alignment reference respectively during the machining process and using the method of adding test tool blocks for auxiliary measurement, the machining and measurement problems of this structure are solved. Using the end face machined in the cylinder-assembled state as the reference surface for the inner cavity machining in the cylinder-split state can also ensure the accuracy of the machining of the upper inner cavity and the lower inner cavity of the cylinder body in the cylinder-split state, avoiding the phenomenon of misalignment during the cylinder-assembling process after the cylinder-split machining. The method described in this application is mainly used for machining the bottleneck-shaped inner hole of the half cylinder of the steam turbine outer cylinder.

Description

Technical Field

[0001] The present invention belongs to the field of machining methods for the inner holes of bearings in the outer cylinder of steam turbines, and particularly relates to a machining method for the bottleneck-type inner holes of the half-cylinder of the outer cylinder of a steam turbine. Background Art

[0002] With the continuous development of steam turbine units towards large capacity, shock absorption and energy consumption reduction, clean energy, etc., the internal cavity design structures of the bearing seats and cylinders of steam turbine units have also changed accordingly. When machining the products of the million-unit project of the machining company, a new type of bearing seat with a bottleneck-type internal cavity appears. This bottleneck-type internal cavity is a bearing internal cavity structure shaped like a glass bottle, with a relatively special type. The inlet and outlet on both sides are small, and the internal cavity is large. If conventional combined-cylinder machining is used, problems such as blocked vision and no remaining operating space for machining will occur, resulting in the inability to guarantee requirements such as the dimensional tolerances and concentricity shown in the figure. Therefore, it must be machined in half, but machining in half will lead to problems such as difficulty in controlling the axial and radial misalignment of teeth and difficulties in controlling dimensional tolerances. This structure exceeds the conventional machining capabilities, has poor machining processability, and has great machining difficulties. Therefore, it is very practical to develop a machining method for the bottleneck-type inner holes of the half-cylinder of the outer cylinder of a steam turbine to overcome the above problems. Summary of the Invention

[0003] In order to solve the problems of poor machining processability and great machining difficulties existing in the bottleneck-type inner holes of the half-cylinder of the outer cylinder of the existing steam turbine, the present invention further provides a machining method for the bottleneck-type inner holes of the half-cylinder of the outer cylinder of a steam turbine;

[0004] A machining method for the bottleneck-type inner holes of the half-cylinder of the outer cylinder of a steam turbine, the method is realized through the following steps:

[0005] Step 1: Clamp the lower half of the cylinder on the machining machine tool, and align it with the axis of the center hole as the alignment basis. After alignment, combine the upper half of the cylinder on the lower half of the cylinder, and tightly connect the lower half of the cylinder and the upper half of the cylinder through bolts;

[0006] Step 2: Machine the inlet end and the outlet end of the bearing inner hole when the lower half of the cylinder and the upper half of the cylinder are in a combined state;

[0007] Step 3: Respectively perform milling machining on the end faces at the front and rear ends of the complete cylinder structure after combining the lower half of the cylinder and the upper half of the cylinder to establish a reference plane at the end;

[0008] Step 4: After establishing the reference plane in Step 3, separate the lower half of the cylinder and the upper half of the cylinder. Align and clamp the lower half of the cylinder with the inlet end and the outlet end of the machined bearing half-hole in the lower half of the cylinder as the reference. Align and clamp the upper half of the cylinder with the inlet end and the outlet end of the machined bearing inner hole in the upper half of the cylinder as the reference;

[0009] Step 5: Arrange a test tool block at each end of the arc surface of the bearing half-hole on the lower half of the cylinder. Each test tool block is detachably connected to the lower half of the cylinder by bolts. Ensure that one end of the test tool block is coplanar with the end of the arc surface of the bearing half-hole, and use a micrometer to measure the aperture of the outlet end and the inlet end of the bearing half-hole in the lower half of the cylinder;

[0010] Step 6: After measuring the inner hole size of the lower half of the cylinder, remove the test tool blocks on the lower half of the cylinder in Step 5, and arrange the two test tool blocks at each end of the arc surface of the machined bearing half-hole in the upper half of the cylinder respectively. Each test tool block is detachably connected to the upper half of the cylinder by bolts. Ensure that one end of the test tool block is coplanar with the end of the arc surface of the bearing half-hole, and use a micrometer to measure the aperture of the outlet end and the inlet end of the bearing half-hole in the upper half of the cylinder;

[0011] Step 7: When ensuring that the aperture of the outlet end and the inlet end of the bearing half-hole in the lower half of the cylinder are both accurate, machine the middle inner cavity of the bearing half-hole in the lower half of the cylinder. When ensuring that the aperture of the outlet end and the inlet end of the bearing half-hole in the upper half of the cylinder are both accurate, machine the middle inner cavity of the bearing half-hole in the upper half of the cylinder;

[0012] Step 8: After machining the middle inner cavity of the bearing half-hole in the lower half of the cylinder and the middle inner cavity of the bearing half-hole in the upper half of the cylinder, reassemble the lower half of the cylinder and the upper half of the cylinder to check the axial and radial misalignment of the inner cavity and the tolerance dimensions shown in the figure, ensuring that the machining quality is qualified;

[0013] Further, the specific steps of machining the inlet end and the outlet end of the bearing inner hole in the state where the lower half of the cylinder and the upper half of the cylinder are combined in Step 2 are as follows:

[0014] Step 21: Select a tool: Select a corn milling cutter with a diameter of 100 mm;

[0015] Step 22: Rough machine the inlet end and the outlet end of the bearing inner hole: Select the following cutting parameters for rough machining: a single-sided allowance of 5 mm, a spindle speed of 300 r / min, a feed rate of 200 mm / min, and leave a machining allowance of 2 mm for finish machining after rough machining;

[0016] Step 23: Re-select a tool: Select a fine boring cutter with a diameter of 125 mm - 320 mm;

[0017] Step 24: Finish machining the inlet end and the outlet end of the bearing inner hole: The following cutting parameters are selected for finish machining: single-pass machining of 0.5 mm, spindle speed of 300 r / min, feed rate of 20 mm / min. The finish machining removes the machining allowance left during rough machining and machines to the specified drawing dimensions of the inlet end and the outlet end of the bearing inner hole;

[0018] Further, the specific steps for milling the end faces at the front and rear ends of the complete cylinder structure after combining the lower half and the upper half of the cylinder in Step 3 are as follows:

[0019] Step 31: Select a tool: A vertical milling cutter with a diameter of 100 mm is selected;

[0020] Step 32: Rough machine the end faces of the inlet end and the outlet end of the bearing inner hole: The following cutting parameters are selected for rough machining: spindle speed of 300 r / min, feed rate of 100 mm / min. After rough machining, a machining allowance of 1 mm is reserved for finish machining;

[0021] Step 33: Finish machine the end faces of the inlet end and the outlet end of the bearing inner hole: The following cutting parameters are selected for finish machining: single-pass machining of 0.5 mm, spindle speed of 300 r / min, feed rate of 20 mm / min. The finish machining removes the machining allowance left during rough machining and machines to the specified drawing dimensions of the end faces of the inlet end and the outlet end of the bearing inner hole;

[0022] Further, the specific steps for machining the middle inner cavity of the bearing half-hole in the lower half of the cylinder in Step 7 are as follows:

[0023] Step 71: Select a tool: A three-edge milling cutter head with a diameter of 250 mm is selected;

[0024] Step 72: Rough machine the radial dimension of the inner cavity of the bearing half-hole in the lower half of the cylinder: The following cutting parameters are selected for rough machining: single-pass machining of 0.5 mm, spindle speed of 300 r / min, feed rate of 200 mm / min. After rough machining, a radial machining allowance of 2 mm is reserved for finish machining;

[0025] Step 73: Select a tool: A fine boring cutter with a diameter ranging from 125 mm to 320 mm is selected;

[0026] Step 74: Finish machine the radial dimension of the inner cavity of the bearing half-hole in the lower half of the cylinder: The following cutting parameters are selected for finish machining: single-pass machining of 0.5 mm, spindle speed of 200 r / min, feed rate of 20 mm / min. The finish machining removes the machining allowance left during rough machining and machines to the specified radial drawing dimensions of the inner cavity of the bearing half-hole;

[0027] Step 75: Select a cutting tool: A three-edge milling cutter head with a diameter of 250 mm is selected as the cutting tool;

[0028] Step 76: Rough machine the axial dimension of the inner cavity of the bearing semi-hole in the lower half of the cylinder block: The following cutting parameters are selected for rough machining: the spindle speed is 220 r / min, the feed rate is 300 mm / min, and a 5-mm axial machining allowance is reserved for finish machining after rough machining;

[0029] Step 77: Select a cutting tool: A three-edge milling cutter head with a diameter of 250 mm is selected as the cutting tool;

[0030] Step 78: Finish machine the axial dimension of the inner cavity of the bearing semi-hole in the lower half of the cylinder block: The following cutting parameters are selected for finish machining: single-pass machining is 0.5 mm, the spindle speed is 2500 r / min, the feed rate is 200 mm / min, the machining allowance left during rough machining is removed during finish machining, and the machining is carried out to the established axial drawing dimension of the inner cavity of the bearing semi-hole;

[0031] Further, the specific steps for machining the middle inner cavity of the bearing semi-hole in the upper half of the cylinder block in Step 7 are as follows:

[0032] Step 7-1: Select a cutting tool: A three-edge milling cutter head with a diameter of 250 mm is selected as the cutting tool;

[0033] Step 7-2: Rough machine the radial dimension of the inner cavity of the bearing semi-hole in the upper half of the cylinder block: The following cutting parameters are selected for rough machining: single-pass machining is 0.5 mm, the spindle speed is 300 r / min, the feed rate is 200 mm / min, and a 2-mm radial machining allowance is reserved for finish machining after rough machining;

[0034] Step 7-3: Select a cutting tool: A fine boring cutter with a diameter ranging from 125 mm to 320 mm is selected as the cutting tool;

[0035] Step 7-4: Finish machine the radial dimension of the inner cavity of the bearing semi-hole in the upper half of the cylinder block: The following cutting parameters are selected for finish machining: single-pass machining is 0.5 mm, the spindle speed is 200 r / min, the feed rate is 20 mm / min, the machining allowance left during rough machining is removed during finish machining, and the machining is carried out to the established radial drawing dimension of the inner cavity of the bearing semi-hole;

[0036] Step 7-5: Select a cutting tool: A three-edge milling cutter head with a diameter of 250 mm is selected as the cutting tool;

[0037] Step 7-6: Rough machine the axial dimension of the inner cavity of the bearing semi-hole in the upper half of the cylinder block: The following cutting parameters are selected for rough machining: the spindle speed is 220 r / min, the feed rate is 300 mm / min, and a 5-mm axial machining allowance is reserved for finish machining after rough machining;

[0038] Step 7-7: Select a cutting tool: A three-edge milling cutter head with a diameter of 250 mm is selected as the cutting tool;

[0039] Step 7: Finish machining the axial dimension of the inner cavity of the bearing semi-hole in the upper half of the cylinder block. For rough machining, select the following cutting parameters: single-point cutting of 0.5 mm, spindle speed of 2500 r / min, and feed rate of 200 mm / min. For finish machining, remove the machining allowance left during rough machining and machine it to the established axial drawing dimension of the inner cavity of the bearing semi-hole.

[0040] Furthermore, when rough machining the radial dimension of the inner cavity of the bearing semi-hole in the lower half of the cylinder block and finish machining the radial dimension of the inner cavity of the bearing semi-hole in the lower half of the cylinder block in Step 6, repeatedly verify the zero point of the center hole to ensure that the central axes of the outlet end and the inlet end of the bearing semi-hole are consistent with the central axis of the inner cavity of the bearing semi-hole. When rough machining the axial dimension of the inner cavity of the bearing semi-hole in the lower half of the cylinder block and finish machining the axial dimension of the inner cavity of the bearing semi-hole in the lower half of the cylinder block in Step 6, machine with the end faces at the front and rear ends of the machined lower half of the cylinder block in Step 3 as the reference planes.

[0041] Furthermore, when rough machining the radial dimension of the inner cavity of the bearing semi-hole in the upper half of the cylinder block and finish machining the radial dimension of the inner cavity of the bearing semi-hole in the upper half of the cylinder block in Step 7, repeatedly verify the zero point of the center hole to ensure that the central axes of the outlet end and the inlet end of the bearing semi-hole are consistent with the central axis of the inner cavity of the bearing semi-hole. When rough machining the axial dimension of the inner cavity of the bearing semi-hole in the upper half of the cylinder block and finish machining the axial dimension of the inner cavity of the bearing semi-hole in the upper half of the cylinder block in Step 7, machine with the end faces at the front and rear ends of the machined upper half of the cylinder block in Step 3 as the reference planes.

[0042] Beneficial effects of the present application compared with the prior art:

[0043] A machining method for the bottleneck-type inner hole of the half cylinder of a steam turbine outer cylinder proposed in the present application, by adopting a split machining method and appropriately adjusting the machining process at the same time, strictly controlling the alignment reference respectively during the machining process and adopting the method of adding a test tool block for auxiliary measurement, solves the machining and measurement problems of this structure. By introducing a test tool block during machining, the accuracy of this structure during machining can be greatly improved, and using the end face machined in the combined cylinder state as the reference plane for machining the inner cavity in the split cylinder state can also ensure the machining accuracy of the inner cavity of the upper part and the lower part of the cylinder block in the split cylinder state, avoiding the phenomenon of misalignment during the combined cylinder process after split cylinder machining. By using the machining method of the present application, the problem of difficult machining can be solved, and the machining quality and production efficiency can be effectively improved, saving production costs and cycle. Subsequent bottleneck structures of other units can also refer to this machining method for machining and detection, providing a new idea for the machining of the inner hole of the bottleneck structure. Description of the Drawings

[0044] Figure 1It is a sectional view schematic diagram of the bearing inner hole to be machined in this application;

[0045] Figure 2 It is a layout schematic diagram of the test tool block during measurement in the method described in this application;

[0046] In the figure, 1 is the lower half of the cylinder, 2 is the upper half of the cylinder, 3 is the machine tool clamping seat, 4 is the test tool block, 5 is the front end face of the bearing inner hole, 6 is the rear end face of the bearing inner hole, 7 is the inlet end of the bearing inner hole, 8 is the outlet end of the bearing inner hole, 9 is the rubber sealing groove at the inlet end of the bearing inner hole, 10 is the rubber sealing groove at the outlet end of the bearing inner hole, and 11 is the inner cavity of the bearing inner hole. Specific implementation mode

[0047] Specific implementation mode 1: Combined with Figures 1 to 2 This implementation mode is described. In this implementation mode, a machining method for the bottleneck inner hole of the outer cylinder half of a steam turbine is provided. The method is realized through the following steps:

[0048] Step 1: Clamp the lower half 1 of the cylinder on the processing machine tool, and align it with the axis of the center hole as the alignment basis. After alignment, combine the upper half 2 of the cylinder with the lower half 1 of the cylinder, and tightly connect the lower half 1 of the cylinder and the upper half 2 of the cylinder through bolts;

[0049] Step 2: Machine the inlet end and the outlet end of the bearing inner hole when the lower half 1 of the cylinder and the upper half 2 of the cylinder are in the combined state;

[0050] Step 3: Respectively mill the end faces at the front and rear ends of the complete cylinder structure after combining the lower half 1 of the cylinder and the upper half 2 of the cylinder to establish the reference planes at the ends;

[0051] Step 4: After establishing the reference planes in Step 3, separate the lower half 1 of the cylinder and the upper half 2 of the cylinder. The lower half 1 of the cylinder is aligned and clamped with the inlet end and the outlet end of the bearing half hole machined in the lower half 1 of the cylinder as the reference, and the upper half 2 of the cylinder is aligned and clamped with the inlet end and the outlet end of the bearing inner hole machined in the upper half 2 of the cylinder as the reference;

[0052] Step 5: Arrange a test tool block 3 at each end of the arc surface of the bearing half hole on the lower half 1 of the cylinder, and each test tool block 3 is detachably connected to the lower half 1 of the cylinder through bolts, ensuring that one end of the test tool block 3 is coplanar with the end of the arc surface of the bearing half hole, and use a micrometer to measure the aperture of the outlet end and the inlet end of the bearing half hole in the lower half 1 of the cylinder;

[0053] Step 6: After the inner hole size of the lower part 1 of the cylinder is measured, the test knife block 3 on the lower part 1 of the cylinder in step 5 is removed, and two test knife blocks 3 are respectively arranged at the two ends of the arc surface of the half hole of the bearing after processing in the upper part 2 of the cylinder, and each test knife block 3 is detachably connected to the upper part 2 of the cylinder by bolts, ensuring that one end of the test knife block 3 is coplanar with the end of the arc surface of the half hole of the bearing, and the outlet end aperture and the inlet end aperture of the half hole of the bearing in the upper part 2 of the cylinder are measured by using a micrometer;

[0054] Step 7: When ensuring that the apertures of the outlet end and the inlet end of the half hole of the bearing in the lower half of the cylinder 1 are accurate, the middle inner cavity of the half hole of the bearing in the lower half of the cylinder 1 is processed; when ensuring that the apertures of the outlet end and the inlet end of the half hole of the bearing in the upper half of the cylinder 2 are accurate, the middle inner cavity of the half hole of the bearing in the upper half of the cylinder 2 is processed;

[0055] Step 8: After the middle inner cavity of the bearing half hole in the lower half of the cylinder 1 and the middle inner cavity of the bearing half hole in the upper half of the cylinder 2 are processed, reassemble the lower half of the cylinder 1 and the upper half of the cylinder 2 to check the axial and radial misalignment of the inner cavity and the tolerance size shown in the figure to ensure the processing quality is qualified.

[0056] In this embodiment, two processing modes, combined cylinder and divided cylinder, are adopted to process the inner cavity and end of the special-shaped bearing hole respectively, thereby ensuring the accuracy of the processing. By introducing a test tool block as a measurement reference for the diameter of the outlet end and the inlet end of the bearing inner hole after processing, the dividing surface can be heightened to expand the measurement range, making it easier to control the tolerance of the semicircular inner hole size, thereby solving the measurement problem of small tolerance and uncontrollable radial bearing gear.

[0057] Specific implementation method 2: Combination Figures 1 to 2 This embodiment is described. The difference between this embodiment and the first embodiment is that the specific steps of processing the inlet end and the outlet end of the bearing inner hole in the step 2 when the cylinder lower part 1 and the cylinder upper part 2 are in a combined state are as follows:

[0058] Step 21: Select the tool: The tool is a corn milling cutter with a diameter of 100mm;

[0059] Step 22: Rough machining the inlet and outlet ends of the inner hole of the bearing: Select the following cutting parameters for rough machining: halo 5mm per side, spindle speed 300r / min, feed rate 200mm / min, and reserve 2mm machining allowance for fine machining after rough machining;

[0060] Step 23: Reselect the tool: Use a fine-tuning boring tool with a diameter of 125mm-320mm;

[0061] Step 24: Finish machining the inlet end and outlet end of the bearing inner hole: The following cutting parameters are selected for finish machining: single-point cutting of 0.5 mm, spindle speed of 300 r / min, and feed rate of 20 mm / min. The finish machining removes the machining allowance left during rough machining and machines the inlet end and outlet end of the bearing inner hole to the specified drawing dimensions.

[0062] Other components and connection methods are the same as those in the first specific embodiment.

[0063] In this embodiment, a five-axis machining center is used as the machining tool. During machining, the position of the workpiece in the combined cylinder state remains unchanged all the time. The tool spindle can be repositioned, and the front and rear ends of the workpiece in the combined cylinder state are machined.

[0064] To ensure the sealing performance of the bearing during operation, a rubber sealing groove 9 at the inlet end of the bearing inner hole and a rubber sealing groove 10 at the outlet end of the bearing inner hole are machined respectively. The machining methods for both are the same. The specific machining steps for the sealing grooves are as follows:

[0065] Step a: Select the tool: A three-sided insert cutter with a diameter of 125 mm is selected.

[0066] Step b: Rough machine the rubber sealing groove at the inlet end and the rubber sealing groove at the outlet end of the bearing inner hole; the following cutting parameters are selected for rough machining: spindle speed of 400 r / min, feed rate of 100 mm / min. After rough machining, a 2-mm machining allowance is reserved for finish machining.

[0067] Step c: Finish machine the rubber sealing groove at the inlet end and the rubber sealing groove at the outlet end of the bearing inner hole; the following cutting parameters are selected for finish machining: single-point cutting of 0.5 mm, spindle speed of 500 r / min, feed rate of 100 mm / min. The finish machining removes the machining allowance left during rough machining and machines to the specified drawing dimensions.

[0068] Specific embodiment three: Figures 1 to 2 This embodiment will be described in combination with... The difference between this embodiment and the second specific embodiment lies in that the specific steps for milling the front and rear end faces of the complete cylinder structure after combining the lower half part 1 and the upper half part 2 of the cylinder in step three are as follows:

[0069] Step 31: Select the tool: A face milling cutter with a diameter of 100 mm is selected.

[0070] Step 32: Rough machine the front end face and the rear end face of the inlet end of the bearing inner hole: The following cutting parameters are selected for rough machining: spindle speed of 300 r / min, feed rate of 100 mm / min. After rough machining, a 1-mm machining allowance is reserved for finish machining.

[0071] Step Three: Finish machining the end faces of the inlet and outlet ends of the bearing inner hole: The following cutting parameters are selected for finish machining: single-pass machining of 0.5 mm, spindle speed of 300 r / min, and feed rate of 20 mm / min. The finish machining removes the machining allowance left during rough machining and machines to the specified drawing dimensions of the end faces of the inlet and outlet ends of the bearing inner hole.

[0072] Other compositions and connection methods are the same as those in the second specific embodiment.

[0073] Specific Embodiment Four: Figures 1 to 2 In describing this embodiment, the difference between this embodiment and the third specific embodiment lies in that the specific steps for machining the middle inner cavity of the bearing half-hole in the lower half part 1 of the cylinder in Step Seven are as follows:

[0074] Step Seven One: Select a tool: A three-edge milling cutter head with a diameter of 250 mm is selected as the tool.

[0075] Step Seven Two: Rough machine the radial dimension of the inner cavity of the bearing half-hole in the lower half part 1 of the cylinder: The following cutting parameters are selected for rough machining: single-pass machining of 0.5 mm, spindle speed of 300 r / min, and feed rate of 200 mm / min. After rough machining, a radial machining allowance of 2 mm is reserved for finish machining.

[0076] Step Seven Three: Select a tool: A fine boring cutter with a diameter ranging from 125 mm to 320 mm is selected as the tool.

[0077] Step Seven Four: Finish machine the radial dimension of the inner cavity of the bearing half-hole in the lower half part 1 of the cylinder: The following cutting parameters are selected for finish machining: single-pass machining of 0.5 mm, spindle speed of 200 r / min, and feed rate of 20 mm / min. The finish machining removes the machining allowance left during rough machining and machines to the specified radial drawing dimensions of the inner cavity of the bearing half-hole.

[0078] Step Seven Five: Select a tool: A three-edge milling cutter head with a diameter of 250 mm is selected as the tool.

[0079] Step Seven Six: Rough machine the axial dimension of the inner cavity of the bearing half-hole in the lower half part 1 of the cylinder: The following cutting parameters are selected for rough machining: spindle speed of 220 r / min and feed rate of 300 mm / min. After rough machining, an axial machining allowance of 5 mm is reserved for finish machining.

[0080] Step Seven Seven: Select a tool: A three-edge milling cutter head with a diameter of 250 mm is selected as the tool.

[0081] Steps Seven and Eight: Finish machining the axial dimension of the inner cavity of the bearing semi-hole in the lower half of the cylinder block 1: For rough machining, select the following cutting parameters: single-pass machining of 0.5 mm, spindle speed of 2,500 r / min, and feed rate of 200 mm / min. For finish machining, remove the machining allowance left during rough machining and machine to the established axial drawing dimension of the inner cavity of the bearing semi-hole.

[0082] Other compositions and connection methods are the same as those in the third specific implementation manner.

[0083] Specific implementation manner five: In combination Figures 1 to 2 To illustrate this implementation manner, the difference between this implementation manner and the fourth specific implementation manner is that the specific steps for machining the middle inner cavity of the bearing semi-hole in the upper half of the cylinder block 2 in step seven are as follows:

[0084] Step Seven 1: Select a tool: Select a three-edge milling cutter head with a diameter of 250 mm.

[0085] Step Seven 2: Rough machine the radial dimension of the inner cavity of the bearing semi-hole in the upper half of the cylinder block 2: For rough machining, select the following cutting parameters: single-pass machining of 0.5 mm, spindle speed of 300 r / min, and feed rate of 200 mm / min. After rough machining, reserve a radial machining allowance of 2 mm for finish machining.

[0086] Step Seven 3: Select a tool: Select a fine boring tool with a diameter ranging from 125 mm to 320 mm.

[0087] Step Seven 4: Finish machine the radial dimension of the inner cavity of the bearing semi-hole in the upper half of the cylinder block 2: For finish machining, select the following cutting parameters: single-pass machining of 0.5 mm, spindle speed of 200 r / min, and feed rate of 20 mm / min. For finish machining, remove the machining allowance left during rough machining and machine to the established radial drawing dimension of the inner cavity of the bearing semi-hole.

[0088] Step Seven 5: Select a tool: Select a three-edge milling cutter head with a diameter of 250 mm.

[0089] Step Seven 6: Rough machine the axial dimension of the inner cavity of the bearing semi-hole in the upper half of the cylinder block 2: For rough machining, select the following cutting parameters: spindle speed of 220 r / min, and feed rate of 300 mm / min. After rough machining, reserve an axial machining allowance of 5 mm for finish machining.

[0090] Step Seven 7: Select a tool: Select a three-edge milling cutter head with a diameter of 250 mm.

[0091] Step 7: Finish machining the axial dimension of the inner cavity of the bearing semi-hole in the upper half 2 of the cylinder block. For rough machining, select the following cutting parameters: single-pass machining of 0.5 mm, spindle speed of 2500 r / min, and feed rate of 200 mm / min. For finish machining, remove the machining allowance left during rough machining and machine it to the established axial drawing dimension of the inner cavity of the bearing semi-hole.

[0092] Other compositions and connection methods are the same as those in the fourth specific implementation manner.

[0093] Specific implementation manner six: Combine Figures 1 to 2 To illustrate this implementation manner, the difference between this implementation manner and the fifth specific implementation manner is that when rough machining the radial dimension of the inner cavity of the bearing semi-hole in the lower half 1 of the cylinder block and finish machining the radial dimension of the inner cavity of the bearing semi-hole in the lower half 1 of the cylinder block in step 7, the zero point of the center hole shall be repeatedly verified to ensure that the central axes of the outlet end and the inlet end of the bearing semi-hole are consistent with the central axis of the inner cavity of the bearing semi-hole. When rough machining the axial dimension of the inner cavity of the bearing semi-hole in the lower half 1 of the cylinder block and finish machining the axial dimension of the inner cavity of the bearing semi-hole in the lower half 1 of the cylinder block in step 7, the end faces at the front and rear ends of the lower half 1 of the cylinder block machined in step 3 shall be used as the reference surfaces for machining. Other compositions and connection methods are the same as those in the fifth specific implementation manner.

[0094] Specific implementation manner seven: Combine Figures 1 to 2 To illustrate this implementation manner, the difference between this implementation manner and the sixth specific implementation manner is that when rough machining the radial dimension of the inner cavity of the bearing semi-hole in the upper half 2 of the cylinder block and finish machining the radial dimension of the inner cavity of the bearing semi-hole in the upper half 2 of the cylinder block in step 7, the zero point of the center hole shall be repeatedly verified to ensure that the central axes of the outlet end and the inlet end of the bearing semi-hole are consistent with the central axis of the inner cavity of the bearing semi-hole. When rough machining the axial dimension of the inner cavity of the bearing semi-hole in the upper half 2 of the cylinder block and finish machining the axial dimension of the inner cavity of the bearing semi-hole in the upper half 2 of the cylinder block in step 7, the end faces at the front and rear ends of the upper half 2 of the cylinder block machined in step 3 shall be used as the reference surfaces for machining. Other compositions and connection methods are the same as those in the sixth specific implementation manner.

[0095] Combined with the sixth and seventh specific implementation manners, when machining the radial dimension of the inner cavity of the bearing semi-hole, the zero point of the center hole shall be repeatedly verified to ensure that the central axes of the outlet end and the inlet end of the bearing semi-hole are consistent with the central axis of the inner cavity of the bearing semi-hole, which is beneficial to ensuring the consistency of the coaxiality of each shaft section of the bearing inner hole. When machining the axial dimension of the inner cavity of the bearing semi-hole, using the end face machined in the combined cylinder state as the reference surface for machining the inner cavity in the separated cylinder state can also ensure the accuracy of machining the inner cavity of the upper part and the lower part of the cylinder block in the separated cylinder state, and avoid the phenomenon of misalignment during the combined cylinder process after separated cylinder machining.

[0096] The present invention has been disclosed above with the preferred embodiments. However, it is not intended to limit the present invention. Any person skilled in the art, without departing from the scope of the technical solution of the present invention, can make some changes or modifications to the above-disclosed structure and technical content to obtain equivalent embodiments of equivalent changes. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A processing method for the bottleneck-shaped inner hole of a half-cylinder of a steam turbine outer cylinder, characterized in that: the method is realized through the following steps: Step 1: Clamp the lower half part (1) of the cylinder on the processing machine tool, and align it with the axis of the center hole as the alignment basis. After alignment, combine the upper half part (2) of the cylinder on the lower half part (1) of the cylinder, and tightly connect the lower half part (1) and the upper half part (2) of the cylinder through bolts; Step 2: Machine the inlet end and the outlet end of the bearing inner hole when the lower half part (1) and the upper half part (2) of the cylinder are in the combined state; Step 3: Milling process the end faces at the front and rear ends of the complete cylinder structure after combining the lower half part (1) and the upper half part (2) of the cylinder respectively to establish the reference plane at the end; Step 4: After establishing the reference plane in Step 3, separate the lower half part (1) and the upper half part (2) of the cylinder. The lower half part (1) is aligned and clamped with the inlet end and the outlet end of the machined bearing half-hole in the lower half part (1) of the cylinder as the reference, and the upper half part (2) of the cylinder is aligned and clamped with the inlet end and the outlet end of the machined bearing inner hole in the upper half part (2) of the cylinder as the reference; Step 5: Arrange a test tool block (3) at both ends of the arc surface of the bearing half-hole on the lower half part (1) of the cylinder, and each test tool block (3) is detachably connected to the lower half part (1) of the cylinder through bolts, ensuring that one end of the test tool block (3) is coplanar with the end of the arc surface of the bearing half-hole, and use a micrometer to measure the aperture of the outlet end and the inlet end of the bearing half-hole in the lower half part (1) of the cylinder; Step 6: After the inner hole size of the lower half part (1) of the cylinder is measured, remove the test tool block (3) on the lower half part (1) of the cylinder in Step 5, and arrange the two test tool blocks (3) at both ends of the arc surface of the machined bearing half-hole in the upper half part (2) of the cylinder respectively, and each test tool block (3) is detachably connected to the upper half part (2) of the cylinder through bolts, ensuring that one end of the test tool block (3) is coplanar with the end of the arc surface of the bearing half-hole, and use a micrometer to measure the aperture of the outlet end and the inlet end of the bearing half-hole in the upper half part (2) of the cylinder; Step 7: When the aperture of the outlet end and the inlet end of the bearing half-hole in the lower half part (1) of the cylinder are both accurate, machine the middle inner cavity of the bearing half-hole in the lower half part (1) of the cylinder. When the aperture of the outlet end and the inlet end of the bearing half-hole in the upper half part (2) of the cylinder are both accurate, machine the middle inner cavity of the bearing half-hole in the upper half part (2) of the cylinder; Step 8: After the middle inner cavities of the bearing half-holes in the lower half part (1) and the upper half part (2) of the cylinder are both machined, re-combine the lower half part (1) and the upper half part (2) of the cylinder to check the axial and radial misalignment of the inner cavity and the tolerance dimensions shown in the figure to ensure that the processing quality is qualified.

2. The processing method for the bottleneck-shaped inner hole of a half-cylinder of a steam turbine outer cylinder according to claim 1, characterized in that: In the second step, the specific steps for machining the inlet end and the outlet end of the bearing inner hole when the lower half (1) and the upper half (2) of the cylinder are in the combined state are as follows: Step 2-1: Select a tool: A corn milling cutter with a diameter of 100 mm is selected. Step 2-2: Rough machine the inlet end and the outlet end of the bearing inner hole: The following cutting parameters are selected for rough machining: The single-sided allowance is 5 mm, the spindle speed is 300 r / min, the feed rate is 200 mm / min, and a machining allowance of 2 mm is reserved for finish machining after rough machining. Step 2-3: Re-select a tool: A fine boring cutter with a diameter of 125 mm - 320 mm is selected. Step 2-4: Finish machine the inlet end and the outlet end of the bearing inner hole: The following cutting parameters are selected for finish machining: The single-pass machining is 0.5 mm, the spindle speed is 300 r / min, the feed rate is 20 mm / min. The machining allowance left during rough machining is removed during finish machining, and the machining is carried out to the established drawing dimensions of the inlet end and the outlet end of the bearing inner hole.

3. A machining method for the bottleneck-type inner hole of a semi-cylinder of a steam turbine outer cylinder according to claim 2, characterized in that: In the third step, the specific steps for milling the end faces at the front and rear ends of the complete cylinder structure after the lower half (1) and the upper half (2) of the cylinder are combined are as follows: Step 3-1: Select a tool: A vertical milling cutter with a diameter of 100 mm is selected. Step 3-2: Rough machine the end faces of the inlet end and the outlet end of the bearing inner hole: The following cutting parameters are selected for rough machining: The spindle speed is 300 r / min, the feed rate is 100 mm / min, and a machining allowance of 1 mm is reserved for finish machining after rough machining. Step 3-3: Finish machine the end faces of the inlet end and the outlet end of the bearing inner hole: The following cutting parameters are selected for finish machining: The single-pass machining is 0.5 mm, the spindle speed is 300 r / min, the feed rate is 20 mm / min. The machining allowance left during rough machining is removed during finish machining, and the machining is carried out to the established drawing dimensions of the end faces of the inlet end and the outlet end of the bearing inner hole.

4. A machining method for the bottleneck-type inner hole of a semi-cylinder of a steam turbine outer cylinder according to claim 3, characterized in that: In the seventh step, the specific steps for machining the middle inner cavity of the bearing semi-hole in the lower half (1) of the cylinder are as follows: Step 7-1: Select a tool: A three-edge milling cutter disk with a diameter of 250 mm is selected. Step 7-2: Rough machine the radial dimension of the inner cavity of the bearing semi-hole in the lower half (1) of the cylinder: The following cutting parameters are selected for rough machining: The single-pass machining is 0.5 mm, the spindle speed is 300 r / min, the feed rate is 200 mm / min, and a radial machining allowance of 2 mm is reserved for finish machining after rough machining. Step 7-3: Select a tool: A fine boring cutter with a diameter of 125 mm - 320 mm is selected. Step 7-4: Finish machine the radial dimension of the inner cavity of the bearing semi-hole in the lower half (1) of the cylinder: The following cutting parameters are selected for finish machining: The single-pass machining is 0.5 mm, the spindle speed is 200 r / min, the feed rate is 20 mm / min. The machining allowance left during rough machining is removed during finish machining, and the machining is carried out to the established radial drawing dimensions of the inner cavity of the bearing semi-hole. Step 75: Select a cutting tool: A three-edge milling cutter head with a diameter of 250 mm is selected as the cutting tool; Step 76: Rough machine the axial dimension of the inner cavity of the bearing semi-hole in the lower half of the cylinder (1): The following cutting parameters are selected for rough machining: the spindle speed is 220 r / min, the feed rate is 300 mm / min, and a 5-mm axial machining allowance is reserved for finish machining after rough machining; Step 77: Select a cutting tool: A three-edge milling cutter head with a diameter of 250 mm is selected as the cutting tool; Step 78: Finish machine the axial dimension of the inner cavity of the bearing semi-hole in the lower half of the cylinder (1): The following cutting parameters are selected for finish machining: single-pass machining is 0.5 mm, the spindle speed is 2500 r / min, the feed rate is 200 mm / min, and the machining allowance left during rough machining is removed during finish machining to machine to the established axial drawing dimension of the inner cavity of the bearing semi-hole.

5. A machining method for the bottleneck-type inner hole of a half cylinder of a steam turbine outer cylinder according to claim 4, characterized in that: The specific steps for machining the middle inner cavity of the bearing semi-hole in the upper half of the cylinder (2) in step 7 are as follows: Step 71: Select a cutting tool: A three-edge milling cutter head with a diameter of 250 mm is selected as the cutting tool; Step 72: Rough machine the radial dimension of the inner cavity of the bearing semi-hole in the upper half of the cylinder (2): The following cutting parameters are selected for rough machining: single-pass machining is 0.5 mm, the spindle speed is 300 r / min, the feed rate is 200 mm / min, and a 2-mm radial machining allowance is reserved for finish machining after rough machining; Step 73: Select a cutting tool: A fine boring cutter with a diameter of 125 mm - 320 mm is selected as the cutting tool; Step 74: Finish machine the radial dimension of the inner cavity of the bearing semi-hole in the upper half of the cylinder (2): The following cutting parameters are selected for finish machining: single-pass machining is 0.5 mm, the spindle speed is 200 r / min, the feed rate is 20 mm / min, and the machining allowance left during rough machining is removed during finish machining to machine to the established radial drawing dimension of the inner cavity of the bearing semi-hole; Step 75: Select a cutting tool: A three-edge milling cutter head with a diameter of 250 mm is selected as the cutting tool; Step 76: Rough machine the axial dimension of the inner cavity of the bearing semi-hole in the upper half of the cylinder (2): The following cutting parameters are selected for rough machining: the spindle speed is 220 r / min, the feed rate is 300 mm / min, and a 5-mm axial machining allowance is reserved for finish machining after rough machining; Step 77: Select a cutting tool: A three-edge milling cutter head with a diameter of 250 mm is selected as the cutting tool; Step 78: Finish machine the axial dimension of the inner cavity of the bearing semi-hole in the upper half of the cylinder (2): The following cutting parameters are selected for finish machining: single-pass machining is 0.5 mm, the spindle speed is 2500 r / min, the feed rate is 200 mm / min, and the machining allowance left during rough machining is removed during finish machining to machine to the established axial drawing dimension of the inner cavity of the bearing semi-hole.

6. A machining method for the bottleneck-type inner hole of a half cylinder of a steam turbine outer cylinder according to claim 4, characterized in that: When rough machining the radial dimension of the inner cavity of the bearing half-hole in the lower half of the cylinder (1) and finish machining the radial dimension of the inner cavity of the bearing half-hole in the lower half of the cylinder (1) in Step 7, the zero point of the center hole shall be repeatedly verified to ensure that the central axes of the outlet end and the inlet end of the bearing half-hole are consistent with the central axis of the inner cavity of the bearing half-hole. When rough machining the axial dimension of the inner cavity of the bearing half-hole in the lower half of the cylinder (1) and finish machining the axial dimension of the inner cavity of the bearing half-hole in the lower half of the cylinder (1) in Step 7, the machining shall be carried out with the end faces at the front and rear ends of the machined lower half of the cylinder (1) in Step 3 as the reference planes.

7. A machining method for the bottleneck-type inner hole of a half-cylinder of a steam turbine outer cylinder according to claim 5, characterized in that: When rough machining the radial dimension of the inner cavity of the bearing half-hole in the upper half of the cylinder (2) and finish machining the radial dimension of the inner cavity of the bearing half-hole in the upper half of the cylinder (2) in Step 7, the zero point of the center hole shall be repeatedly verified to ensure that the central axes of the outlet end and the inlet end of the bearing half-hole are consistent with the central axis of the inner cavity of the bearing half-hole. When rough machining the axial dimension of the inner cavity of the bearing half-hole in the upper half of the cylinder (2) and finish machining the axial dimension of the inner cavity of the bearing half-hole in the upper half of the cylinder (2) in Step 7, the machining shall be carried out with the end faces at the front and rear ends of the machined upper half of the cylinder (2) in Step 3 as the reference planes.

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