Method for finishing high concentricity oil distribution shaft for ship

Abstract

The present application relates to a kind of high concentricity oil distribution shaft finishing method for ship, the design of special cover size at both ends, ensure the accuracy of center hole after installation;Fine turning process, cooperate with advanced HSF1 type ultrasonic thickness gauge monitoring workpiece wall thickness value ensure the workpiece deep hole and outer diameter 0.05mm concentricity. Formulate "temperature compensation principle and method of precision parts size measurement", temperature compensation is used in precision machining to minimize measurement error. Deep hole drilling and boring machine has been unable to complete the oil distribution shaft inner hole ∅250H8, ∅230H8 roughness Ra3.2 step deep hole processing, reform deep hole boring equipment increases inner hole honing head to solve the problem, using digital electronic percentage table measuring instrument group solves the problem of detection. Use modular special tool combined with tungsten steel shockproof tool bar to complete the processing of reverse R angle inside waist type groove, significantly improve efficiency. Use CAM software to select tool parameters analysis, optimization, calculation and generation program, develop reverse thinking programming, ensure that tool path is clear, reliable, good stability.

Description

Technical Field

[0001] The invention relates to a finishing method for a high-concentricity oil distribution shaft for ships, which can reach foreign oil distribution shaft processing technical parameters. Background Art

[0002] Many renowned European propulsion manufacturers have mature products supporting variable-pitch propellers. Companies like Wärtsilä and MAN have long histories in developing variable-pitch propellers, and their products command a significant market share in the shipping industry. With the booming maritime trade and the growing competition in military equipment development among nations, the technology behind variable-pitch propeller systems is undergoing continuous refinement and diversification. However, each company names the oil distribution shaft differently: Wärtsilä calls it the "Servo Shaft," while MAN Diesel calls it the "OD Shaft." As a key component in variable-pitch propeller systems, the oil distribution shaft performs the same primary function. Modern hydrodynamic system analysis, design, and optimization tools are used to analyze a vessel's navigation patterns and integrate the results into propulsion system design to meet the demanding requirements of modern shipping.

[0003] Wärtsilä Propulsion Systems of Finland provides complete modular variable-pitch propulsion systems to navies worldwide. Solutions are customized for naval applications to meet demanding requirements such as high shock, low noise, and vibration levels. Its controllable pitch propellers for naval vessels can reach up to 50 MW and can be used in OPVs, frigates, destroyers, and aircraft carriers. Its controllable pitch propeller systems offer exceptional reliability, low operating costs, environmental friendliness, easy installation / integration, and intuitive operational controls. Using methods such as hydrodynamic design, cavitation analysis, and propeller-induced pressure and stress analysis, four- and five-blade propellers are specifically designed to suit the projected operating profiles. The CPP system includes a hub, propeller blades, shafting, hydraulics, a remote control system, and any additional accessories required to meet naval requirements.

[0004] MAN Diesel's CPP variable pitch propulsion system has been granted multiple patents. MAN Diesel has extensive experience manufacturing Alpha propellers. The practical and reliable design principles have proven their suitability for the variable pitch propellers required by a wide range of vessels, including ferries, tankers, container ships, cruise ships, offshore vessels, dredgers, and naval vessels. It not only provides maximum speed and freedom of movement, but also maximizes towing power and maneuverability through the Alphatronic rapid-response control system and high-power reverse. Currently, the Alpha CPP combination handles engine outputs up to 30,000 kW and is equipped with a shaft generator. Alpha Propeller's main models include: VBS860 / 8L27 / 38 main engine, VBS1800 / 7S60MC-C main engine, VBS1380 / 6L48 / 60B main engine, VBS1680 / 8S50MC-C, etc. Different oil distribution shaft systems can be selected to meet different power, speed and ice class requirements. This series of controllable pitch propellers all have excellent performance in economy and ease of operation. Summary of the Invention

[0005] Design purpose: Based on the existing domestic machining equipment and machining methods, a high concentricity oil distribution shaft finishing method for ships is designed that can achieve the foreign oil distribution shaft processing technical parameters.

[0006] Design scheme: In order to achieve the design purpose of the present invention, the present invention adopts the following methods in the process of implementing the high concentricity oil distribution shaft finishing method for ships:

[0007] 1.1 Technical requirements for oil distribution shaft:

[0008] 1.1.1 Dimensional Accuracy Requirements: 1) Oil distribution shaft: Material: 34CrMo1, flange outer diameter φ1140h7mm, flange hole precision for coupling φ90H7, roughness Ra0.8, end face runout 0.06mm, outer diameter φ525, mating with bearing shell roughness Ra0.4, bearing stop outer diameter concentricity with respect to inner bore AB reference requirement φ0.05mm, outer diameter of stern shaft connection ∅510f6, roughness Ra1.6, cylindricity requirement 0.025mm, total runout 0.025mm, pitch feedback groove dimensions 460x80+0.207+0.12, roughness requirement Ra0.8. Deep hole runs through the entire shaft, inner bore precision H8. Roughness requirements for both surfaces of the valve seat mounting are Ra0.8, flatness 0.05mm. The oil outlet hole of the two-phase locking valve is ∅38h8 and the roughness is Ra1.6.

[0009] 1.1.2 The surface quality and ultrasonic flaw detection of forgings shall comply with Appendix C of CB / T 4312-2013.

[0010] 1.1.3 The 12-φ90H7 flange hole of this product needs to be hinged with the coupling flange to ensure assembly accuracy. The outer diameter of the shaft body φ525 is a key and important dimension and needs to be ground with the inner diameter of the oil distributor sealing bearing.

[0011] 2.1 Technical Analysis:

[0012] The outer diameter of the component must precisely mate with the bearing. To ensure smooth operation and low noise, strict runout requirements are imposed on each gear. The product's internal structure is complex and demands high precision. The deep hole through the oil distribution shaft has a roughness of Ra3.2 and a machining depth of 6840mm. Meanwhile, concentricity with the outer diameter must be guaranteed to 0.05mm. This project also demands high internal hole precision. Due to the depth of the inner hole, the resolution of conventional ultrasonic wall thickness gauges is insufficient to effectively measure the coaxial accuracy with the outer diameter. Measurement methods such as internal hole drilling are also impractical. To ensure smooth processing and acceptance, precise measurement tools are essential to effectively measure the concentricity requirements between the inner and outer diameters. The outer diameter of the tail end that mates with the inner hole of the coupling has a roundness of 0.025, and a total runout requirement of 0.025. These requirements present significant processing risks and manufacturing challenges during the finishing process. Every component of the CPP variable pitch propulsion system must meet design precision requirements. The level of manufacturing accuracy directly affects the propeller's hydrodynamic characteristics, propulsion efficiency, and hull vibration and noise. It is particularly important to formulate a scientific and reasonable production process route.

[0013] 3.1 Difficulties and innovations of the present invention:

[0014] Difficulty 1: The inner hole and outer circle of the product have a concentricity requirement of 0.05. It is very difficult to ensure this accuracy during processing. The quality of the center hole covers at both ends of the shaft and the incorrect installation angle will cause the center reference of the inner hole to be unable to be accurately converted to the outer circle. During the processing, an ultrasonic thickness gauge with a resolution of 0.01mm is required to detect the wall thickness value, because the turning stress will also cause the shaft to bend and deform, resulting in the inner hole straightness of the shaft becoming more and more curved and the concentricity being out of tolerance.

[0015] Difficulty 2: The outer diameter of the bearing shell fit is the most critical dimension of the product. This outer diameter requires high precision and tight tolerances. Factors such as ambient temperature, measurement techniques, and machining operations during machining and measurement can directly impact product accuracy, resulting in product rejection. Before machining this dimension, a scientific and rational machining and measurement process must be developed based on the product's characteristics, and appropriate fixtures must be manufactured to ensure that the specifications specified in the drawings are met.

[0016] Difficulty 3: The internal actuators of the oil distribution shaft have precise matching requirements. For example, the tolerance between the push rod and the inner hole is ∅250H8, the effective machining depth reaches 1871mm, and the oil pipe hole ∅230H8 is 4969mm deep with a roughness of Ra3.2. Ordinary deep-hole drilling machines are no longer able to meet these precision requirements. The shaft of the part also has two axial ∅42 high-pressure oil holes, with the orifices extending from the flange end face to 2590mm. The drilling of these holes requires a drill bit aspect ratio of 62:1. Machining holes of such depth inevitably involves many difficulties, such as poor tool rigidity, weak cutting guidance, difficult chip removal, and difficulty in observation, which ultimately lead to poor hole quality.

[0017] Difficulty 4: Various holes and grooves in the parts have high requirements for the R angle roughness of the intersecting arcs, especially the internal transition R arc of the waist groove and the symmetry of the 80+0.207+0.12 groove wall, which requires a roughness of 0.08mm to reach Ra1.6 ( Figure 2 This groove is used as a slider for the pitch feedback device when the oil distribution shaft is working. It is difficult to meet the design requirements by using ordinary machining methods. New process ideas and special tools must be adopted to meet the requirements of the drawing.

[0018] Difficulty 5: In order to ensure that the flange hole and the coupling hole have good positioning accuracy, the two parts need to be assembled and then hinged. Before hinged, the φ90H7 holes on the two parts are pre-machined to a margin of 0.02~0.035mm, a roughness of Ra1.6, and the position accuracy of the holes is guaranteed. After the coupling is assembled with the dummy shaft, oil pressure is applied to keep the flange surface in a tightened state to process the pre-reamed holes. Otherwise, the pin hole position of the coupling flange will deviate from the working state after tightening when no pressure is applied. The flange installation process of the two parts is difficult and has the risk of bumps and scratches. It is necessary to solve the effective control of maintaining the balance of parts during lifting. When operating the centering flange pin hole, the design and installation process of the zero-time installation pin need to be evaluated. It should be reliable and the tooling should be scientific and reasonable to ensure good assembly accuracy, high safety and convenient operation.

[0019] Innovation 1: The design of special blind caps at both ends ensures the accuracy of the center hole after installation; refined turning processing technology, combined with advanced HS F1 ultrasonic thickness gauge to monitor the workpiece wall thickness, ensures the concentricity of the workpiece deep hole and outer diameter is 0.05mm;

[0020] Regarding fixtures: First, ensure that the straightness of the finely machined inner hole is within 0.03mm and the roundness is no greater than 0.02mm. The runout between the center hole of the blind cap installed at both ends and the interference fit stop must be within 0.005mm. The outer diameter of the φ230 stop is designed with a 5x15° guide bevel to ensure correct guidance during installation. When installing the center hole blind cap, use a dedicated balanced lifting device to smoothly insert it into the matching inner hole. Use a tool hammer to evenly strike the outer end face until the mating surface and the shaft end face are precisely aligned without gaps. Use a 0.01mm feeler gauge to check for complete fit.

[0021] Regarding machining technology: The workpiece is clamped and calibrated on a CK61250 CNC lathe with two tops and one support. The runout of the outer diameter reference tape on both ends should be less than 0.015. A center rest is placed on the shaft body. The turning amount per turn is no more than 1mm per side. Five measuring tapes are evenly distributed on the shaft outer circle. An ultrasonic wall thickness gauge is used to measure each section in a "M" direction. The difference is calculated to determine whether the coaxiality is within the tolerance range. The runout value of the gauge tape is checked after each machining operation. The normal value should be ≤0.05mm. Coolant is applied during the machining process to prevent the shaft from being "bent" due to overheating of the workpiece and machining stress.

[0022] Innovation 2: Because changes in measuring tool temperature and parts can cause measured dimensional deviations, the "Temperature Compensation Principles and Methods for Precision Part Dimension Measurement" was formulated, and temperature compensation was used in precision machining to minimize measurement errors.

[0023] In view of the product's precise dimensional accuracy and roughness requirements, grinding is established as the final finishing process to reduce quality risks such as dimensional deformation and bumps during the production process. At the same time, based on the small dimensional tolerance of the bearing bush fitting, a 0.05-0.1mm allowance is left after rough grinding for natural aging for 12 hours to reduce the influence of grinding temperature and improve dimensional stability. The direct coefficient compensation method is used to compensate the measured value during measurement: △L=L[α1(t1-20°C)-α2(t2-20°C)]; where: L is the measured dimension, α1 is the linear expansion number of the measuring tool, α2 is the linear expansion number of the measured workpiece, t1 is the measuring tool temperature, and t2 is the workpiece temperature. If α1=α2, △L=Lα(t1-t2); see Figure 3 : Dimension temperature compensation calculation table, and stipulate in the processing measurement that each measurement must be calibrated with a calibration rod to eliminate the influence of the temperature rise of the measuring tool during measurement on the accuracy of the measurement result. At the same time, the bearing and matching parts are transported to the processing site and the comparative measurement method is used at the same temperature to meet the clearance tolerance requirements of the drawing. In order to ensure the cylindricity of 0.01 and the roughness of Ra0.4 of this gear, the product is first used to perform simulated finishing with a margin to verify whether the processing accuracy of the grinding machine equipment can meet the product requirements. At the same time, the process parameters such as cutting amount and tools such as diamond pens are verified.

[0024] Innovation point 3: The deep hole boring equipment is modified to increase the inner hole honing head to solve the difficult problem, and the digital electronic dial gauge set is used to solve the detection problem.

[0025] The depth of the through deep hole in the product reaches 6.8 meters, and the roughness and geometric tolerance requirements are high. The traditional processing method cannot meet the processing requirements. After comparison and analysis, it is considered that special deep hole drilling and boring equipment should be used for processing, and honing tooling is added after the floating boring to ensure the geometric requirements and improve the surface roughness. In addition, the detection of the inner hole of the product is also difficult. The ordinary inner diameter measuring instrument or three coordinate measuring machine cannot enter the narrow inner hole for measurement operation. After the technical team's efforts, a method of using an electronic percentage table for cylindricity detection on a horizontal lathe is developed. This method has the advantages of high measurement accuracy, good reliability, strong anti-interference ability, and high detection efficiency. The specific operation method is as follows:

[0026] ①. The outer circle of the part blank is turned at the position of 2 / 8 of the total length, and two center frame positions are turned out, with a frame width of 100mm, a roughness of Ra1.6, and a roundness requirement of 0.015mm;

[0027] ②. One clamping and one supporting are used for deep hole drilling and boring machine, and the patent number CN201521109245.4 "Deep hole drilling and boring machine positioning guide sleeve tool" is used to process deep hole drilling and boring, and the honing amount is left after floating boring;

[0028] ③. The honing head is installed into the deep hole drill rod, and the honing process is carried out by injecting grinding fluid into the hole, controlling the influence of grinding temperature on size, and controlling the roundness within 0.005mm and the straightness within 0.01mm;

[0029] ④. The electronic percentage table measuring needle head is installed into the deep hole drill rod end, the measuring needle head is connected with the electronic watch dial by several meters of data line, the workpiece is rotated against the table at the hole, the measuring needle installation position is confirmed to be stable, the drill rod is inserted into the deep hole measurement area, the workpiece is rotated to observe the degree of the electronic display percentage table, and the value change is less than 0.015mm to determine that it is qualified;

[0030] Innovation point 4: The waist-shaped groove internal reverse R angle is processed by using the module type special tool combined with the tungsten steel shockproof tool bar, which significantly improves the production efficiency. The numerical control programming software (CAM) is used to select tool parameters to analyze, optimize, calculate and generate programs, develop reverse thinking programming, ensure clear and reliable tool path, and reduce the labor intensity of operators.

[0031] a) To address the current difficulties in part machining, the part was converted into a 3D drawing for simulated machining, with tool paths verified during debugging. Ultimately, a modular T-type tool with a tungsten steel anti-vibration toolholder was chosen to machine the fillet. Given the high value of the part, a trial cut using a semicircular plate was performed. Only after successful machining of the test piece confirmed the tool's reliability and tool path safety could the product be officially cut. The process steps are as follows:

[0032] Create 3D blank contour → determine cutting parameters → analyze tool type → set cutting strategy → generate tool path → simulate machining → analyze and optimize machining parameters → export machining program → cutting machining.

[0033] The R10 fillet program for the inside of the hole uses reverse thinking for programming. The principle is to assume that the positive direction of the tool axis is at the center of the inner hole of the machined part. The oil distribution shaft is cut open in the software for 3D visualization and tool path debugging. After the program code is generated, the negative value of Z is replaced with a positive value. This programming method also provides new ideas and solutions for the future machining of other internal cavity structure parts. The advantages of this machining method are:

[0034] ①. Use tungsten steel anti-vibration tool holder with modular T-type tool to process the reverse R arc area, which increases the rigidity of the tool to prevent severe vibration during processing and improves the quality of the processed surface and processing efficiency;

[0035] ②. Tungsten steel anti-vibration tool bars are expensive, and modular detachable tool heads are used. After cutting and wear, only the tool heads need to be replaced, reducing the cost of tool use;

[0036] ③. The use of 3D visual operation makes programming, simulation, and processing operations simple and easy to understand, reducing the labor intensity of manual grinding operations and saving labor costs;

[0037] ④. The software uses negative-axis programming. When setting the tool, there is no need to set complete T-type tool parameters. Only ordinary milling cutters are required. After generating the machining code, the Z feed direction is replaced. The first machining is carried out on a test piece. After verifying the program, it is safe and reliable.

[0038] b) The waist-shaped groove width dimensional accuracy requirements are 80 + 0.207 + 0.1, the groove wall symmetry is required to be 0.08mm, the roughness reaches Ra1.6, and the effective processing depth of the groove wall reaches 210mm. Ordinary rod milling cutters are difficult to achieve this accuracy. The tool length-to-diameter ratio exceeds 3 times, and the groove edge will cause the tool to yield. After technical analysis, a ∅70 alloy-inserted milling cutter was selected. The tool shank was roughened to increase rigidity, and an allowance was left during processing for imitation finishing. Confirm whether the dimensional taper and roughness meet the drawing requirements. The specific process route is as follows:

[0039] ①. Use the ∅70 drill to drill through the waist-type groove side wall bottom hole, and expand the hole to ∅80.2 with a boring cutter;

[0040] ②. Use a ∅50 square shoulder milling cutter to rough mill the waist-type groove side wall, leaving a single-sided 0.5mm light tool allowance;

[0041] ③. Recheck the workpiece coordinate system, and use a ∅70X110L alloy milling cutter to finish milling the 80+0.207+0.1 side wall. Check the groove cross-sectional size in sections to see if there is a taper. If there is a taper deviation, the tool path needs to be corrected.

[0042] ④. Finish milling the 80 width to the requirements of the drawing. The milling process must be cooled with a cooling liquid. The milling method is down milling. After the machining is completed, check the straightness of the groove wall and the position of the groove to confirm that the symmetry meets the 0.08mm requirement.

[0043] Innovation point 5: The hoisting problem of the oil distribution shaft flange and the shaft coupling assembly is solved. Two large interference nylon positioning pins are used to hit the two flanges with a hydraulic cylinder, ensuring that the centering error during assembly is controlled within 0.02mm. Manual honing is used to complete the fine grinding of the flange holes of the two components, ensuring good pin hole size accuracy.

[0044] a) In order to make the connecting flange hole of the oil distribution shaft and the expanded working state of the shaft coupling have good installation position, the two components need to be pre-processed and honed to ensure the size consistency and roughness of the hole. The size of the oil distribution shaft is 6.8 meters long. Considering the large size, first place the shaft horizontally on the V-shaped iron bracket, then hoist the shaft coupling stably, adjust the flange angle to about 5° forward, and slowly approach the oil distribution shaft flange. Use a collision protection wood to protect the flanges on both sides to prevent the fine machining surface from being damaged. Prepare two nylon pins with an interference of 1mm. Design a 10X5° guide cone at one end of the pin. Drill a ∅31 hole in the inner hole to pass an M30 screw. Use the oil pressure of the electric hydraulic station to hit the two flange holes with a nylon pin, so that the pin holes coincide. Adjust the height of the crane hoist to make the two flange planes fit together, and lock them with M30 bolts at adjacent hole positions. Then use the hydraulic station to press the remaining nylon pin into the 180° position pin hole. Figure 4 Adjust the height of the crane hoist according to the fitting gap of the flange face, and finally lock the two flange faces with 2 sets of M30 bolts. The shaft coupling dummy shaft tail end is fixed with an adjustable support pad. Check if there is a gap between the fitting surfaces with a 0.02mm plug gauge. Use a knife edge gauge to check the outer circle of the two flanges. If it is not transparent, it is qualified.

[0045] b) Honing oilstones are required to have strong cutting ability, good self-sharpening and shape retention properties. According to the actual grinding volume, a particle size of 120 mesh is selected. Oil grinding fluid needs to be added during the grinding process. The viscosity of the grinding fluid will affect the efficiency of honing, so a grinding fluid with relatively low viscosity needs to be selected. Mechanical reciprocating feed is used for rough grinding, and manual reciprocating feed is used to complete the final fine grinding. This honing method mainly improves the roughness of the hole to Ra0.8 and controls the roundness to 0.01. The operation method is to first insert the honing head into the hole, manually adjust the nut to expand the oilstone strip, and the force is controlled according to the actual experience of the operator. Figure 5 ).

[0046] Compared with the background technology, after nearly three years of research and development, the present invention has developed a method for finishing a high concentricity oil distribution shaft for ships, and its key process steps have reached the following detection technical parameters, namely:

[0047]

[0048] The key dimensions meet the inspection dimensions in the following table, namely:

[0049] BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is a partial cross-sectional view of the oil distribution shaft. This drawing is only used as a reference for the finishing method of high concentricity oil distribution shafts for ships, and there is no requirement for the clarity of the drawing.

[0051] Figure 2 This is a schematic diagram of waist groove processing.

[0052] Figure 3 It is a calculation table of size temperature compensation.

[0053] Figure 4 This is a photo of the assembly process of the oil distribution shaft and the coupling. If it does not meet the requirements, it can be deleted.

[0054] Figure 5 This is a photo of flange hole honing. If it does not meet the requirements, it can be deleted. DETAILED DESCRIPTION

[0055] Example 1: Refer to the attached Figure 1-5 A method for finishing a high concentricity oil distribution shaft for ships, characterized by:

[0056] (1) Fixtures: Ensure that the straightness of the inner hole after fine processing is within 0.03mm and the roundness is not greater than 0.02mm. The center hole of the cover installed at both ends and the interference fit stopper need to be within 0.005mm. The outer circle of the φ230 stopper is designed with a 5X15° guide bevel to facilitate correct guidance during installation. When installing the center hole cover, use a balanced hanger to smoothly enter the matching inner hole. Use a tool hammer to evenly strike the outer end face until the matching surface and the end face of the shaft body are precisely fitted without gaps. Use a 0.01mm feeler gauge to check whether it is completely fitted.

[0057] (2) Processing technology: The workpiece is clamped and calibrated on a CK61250 CNC lathe with two tops and one support. The outer circle reference tape of the two ends should have a runout of less than 0.015. A pair of center frames are placed on the shaft body. The turning amount each time is no more than 1mm on a single side. Five measuring tapes are evenly distributed on the outer circle of the shaft. Each section is measured in a M-shaped direction using an ultrasonic wall thickness gauge. The difference is calculated to determine whether the coaxiality is within the tolerance range. The runout value of the tape is checked after each cut. The normal value should be ≤0.05mm.

[0058] After rough grinding, a 0.05-0.1mm stock is left for natural aging for 12 hours to reduce the influence of grinding temperature and improve dimensional stability. During measurement, the direct coefficient compensation method is used to compensate the measured value: L=L[α1(t1-20°C)-α2(t2-20°C)], where: L is the measured dimension, α1 is the linear expansion number of the measuring tool, α2 is the linear expansion number of the measured workpiece, t1 is the measuring tool temperature, and t2 is the workpiece temperature. If α1=α2, △L=Lα(t1-t2);

[0059] During machining, it is stipulated that each measurement must be calibrated using a calibration rod to eliminate the influence of the temperature rise of the measuring tool during measurement on the accuracy of the measurement results. At the same time, the bearing and mating parts are transported to the machining site and compared with the measurement method at the same temperature to achieve the clearance tolerance requirements of the drawing. To ensure the cylindricity of 0.01 and the roughness of Ra0.4 of this gear, the product is first used for simulated finishing with an allowance to verify whether the machining accuracy of the grinding equipment can meet the product requirements. At the same time, the process parameters such as cutting amount and tools such as diamond pens are verified.

[0060] (3) The depth of the through hole in the middle of the product reaches 6.8 meters. The method of using an electronic dial indicator to detect the cylindricity on a horizontal lathe is as follows:

[0061] ① Two center racks are machined on the outer circle at 2 / 8 of the total length of the part blank. The rack width is 100mm, the roughness is Ra1.6, and the roundness requirement is 0.015mm.

[0062] ②Shaft on deep hole drilling and boring machine one clamping one supporting clamping, using deep hole drilling and boring machine processing positioning guide sleeve tooling method processing drill, expanding and boring deep hole, floating boring tool processing leaving honing allowance;

[0063] ③The honing head is installed into the deep hole drill rod, and grinding fluid is injected into the hole for honing processing. The influence of grinding temperature on size can be controlled within 0.005 mm, and the straightness is 0.01 mm;

[0064] ④The electronic dial gauge needle is installed into the end of the deep hole drill rod, and the needle is connected to the electronic dial with several meters of data line. The dial is rotated against the workpiece at the hole, and after confirming that the installation position of the needle is stable, the drill rod is inserted into the deep hole measurement area. Rotate the workpiece and observe the degree of the electronic display dial gauge. If the numerical value changes less than 0.015 mm, it is judged as qualified;

[0065] (4) When assembling the oil distribution shaft flange and the shaft coupling, the lifting is carried out through two large interference nylon positioning pins, which are punched into two flanges by hydraulic cylinders to ensure that the centering error during assembly is controlled within 0.02 mm;

[0066] (5) The internal reverse R angle of the waist-shaped groove is completed by using a modular special tool combined with a tungsten steel shockproof tool bar.

[0067] The modular special tool refers to a modular T-shaped tool combined with a tungsten steel shockproof tool bar to process the round corner. The process steps of the modular special tool are as follows:

[0068] Create 3D blank contour → determine cutting parameters → analyze tool type → set tool path strategy → generate tool path → simulate machining → analyze and optimize machining parameters → export machining program → cutting machining;

[0069] The R10 round corner program inside the hole uses reverse thinking for programming. The principle is to assume that the positive direction of the tool axis is at the center of the machined part's internal hole. In the software, the oil distribution shaft is cut open for 3D visualization observation and tool path debugging. After generating the program code, the negative value of Z is replaced with a positive value to operate.

[0070] The waist-shaped groove width size precision requirement is 80+0.207+0.1, the groove wall symmetry requirement is 0.08 mm, the roughness reaches Ra1.6, and the effective processing depth of the groove wall reaches 210 mm. Select a ∅70 carbide milling cutter, increase the rigidity of the tool handle, and perform rough machining and then finish machining with a certain allowance. The specific process route is as follows:

[0071] ① Use a ∅70 drill bit to drill through the waist-shaped groove side wall bottom hole, and expand the boring to ∅80.2;

[0072] ② Use a ∅50 square shoulder milling cutter to rough mill the waist-shaped groove side wall, leaving a single-sided 0.5 mm light tool allowance;

[0073] 3. Review the workpiece coordinate system, and use the ∅70X110L alloy milling cutter to finish milling 80+0.207+0.1 side wall, check the groove section size in sections, and whether there is taper, if there is taper deviation, the tool path needs to be corrected;

[0074] 4. Finish milling 80 width to the requirement of the drawing, and the processing process must be poured with cooling liquid, the milling method is down milling, after the processing is finished, check the straightness of the groove wall, check the position degree of the groove, and confirm that the symmetry degree satisfies 0.08mm.

[0075] It should be understood that: the above examples, although the design idea of the present application is described in detail, these descriptions are only a simple description of the design idea of the present application, but not a limitation of the design idea of the present application, any combination, addition or modification which does not exceed the design idea of the present application falls within the scope of the present application.

Claims

1. A method for finishing a high concentricity oil distribution shaft for ships, characterized by: (1) Fixtures: Ensure that the straightness of the inner hole after fine processing is within 0.03mm and the roundness is not greater than 0.02mm. The center hole of the cover installed at both ends and the interference fit stopper need to run out within 0.005mm. The outer circle of the φ230 stopper is designed with a 5X15° guide bevel to facilitate correct guidance during installation. When installing the center hole cover, use a balanced hanger to smoothly enter the matching inner hole. Use a tool hammer to evenly strike the outer end face until the matching surface and the end face of the shaft body are precisely fitted without gaps. Use a 0.01mm feeler gauge to check whether it is completely fitted. (2) Processing technology: The workpiece is clamped and calibrated on a CK61250 CNC lathe with two tops and one support. The outer circle reference tape of the two ends should have a runout of less than 0.

015. A pair of center frames are placed on the shaft body. The turning amount each time is no more than 1mm on a single side. Five measuring tapes are evenly distributed on the outer circle of the shaft. Each section is measured in a M-shaped direction using an ultrasonic wall thickness gauge. The coaxiality is determined by calculating the difference to see if it is within the tolerance range. The runout value of the measuring tape is checked after each cut. The normal value should be ≤0.05mm. After rough grinding, a 0.05-0.1mm stock is left for natural aging for 12 hours to reduce the influence of grinding temperature and improve dimensional stability. During measurement, the direct coefficient compensation method is used to compensate the measured value: △L=L[α1(t1-20°C)-α2(t2-20°C)], where: L is the measured dimension, α1 is the linear expansion coefficient of the measuring tool, α2 is the linear expansion coefficient of the measured workpiece, t1 is the measuring tool temperature, and t2 is the workpiece temperature. If α1=α2, △L=Lα(t1-t2); During machining, it is stipulated that each measurement must be calibrated using a calibration rod to eliminate the influence of the temperature rise of the measuring tool during measurement on the accuracy of the measurement results. At the same time, the bearing shell mating parts are transported to the machining site and compared with the parts at the same temperature to achieve the clearance tolerance requirements of the drawing. To ensure the cylindricity of the outer circle φ525 is 0.01 and the roughness of the mating with the bearing shell is Ra0.4, the product is first used for simulated finishing with an allowance to verify whether the machining accuracy of the grinding equipment can meet the product requirements. At the same time, the cutting amount process parameters and diamond pen tools are verified. (3) The depth of the through hole in the middle of the product reaches 6.8 meters. The method of using an electronic dial indicator to detect the cylindricity on a horizontal lathe is as follows: ① Two center racks are machined on the outer circle at 2 / 8 of the total length of the part blank. The rack width is 100mm, the roughness is Ra1.6, and the roundness requirement is 0.015mm. ② The deep hole drilling and boring machine on the shaft is clamped with one clamp and one support. The deep hole drilling and boring machine is used to process the positioning guide sleeve tooling for drilling and expanding deep holes. The floating boring tool is left with honing allowance after processing. ③Install the honing head into the deep hole drill rod, inject grinding fluid into the hole for honing, control the effect of grinding temperature on size, and control the roundness within 0.005mm and the straightness within 0.01mm; ④ Install the electronic dial indicator probe into the end of the deep hole drill rod, connect the probe to the electronic dial with a data cable, rotate the workpiece at the hole mouth, confirm that the probe installation position is stable, then extend the deep hole drill rod into the deep hole measurement area, rotate the workpiece to observe the reading of the electronic dial indicator, and judge it as qualified if the value change is less than 0.015mm; (4) When assembling the oil distribution shaft flange and the coupling, two large interference fit nylon positioning pins are driven into the two flanges by a hydraulic cylinder to ensure that the centering error during assembly is controlled within 0.02mm; (5) A modular special tool combined with a tungsten steel anti-vibration tool bar is used to complete the internal R angle processing of the waist groove.

2. The method for finishing a high concentricity oil distribution shaft for ships according to claim 1 is characterized by: The modular special tool refers to a modular T-shaped tool combined with a tungsten steel vibration-proof tool bar to process the R fillet inside the waist groove.

3. The method for finishing a high concentricity oil distribution shaft for ships according to claim 2 is characterized by: The process steps of modular special tool are as follows: Create 3D blank contour → determine cutting parameters → analyze tool type → set cutting strategy → generate tool path → simulate machining → analyze and optimize machining parameters → export machining program → cutting; The R10 fillet program inside the hole is programmed using reverse thinking. The principle is to assume that the positive direction of the tool axis is at the center of the inner hole of the machined part. The oil distribution shaft is cut open in the software for 3D visualization and tool path debugging. After the program code is generated, the negative value of Z is replaced with a positive value.

4. The method for finishing a high concentricity oil distribution shaft for ships according to claim 2 is characterized by: Waist groove width dimensional accuracy requirements The symmetry of the groove wall is required to be 0.08mm, the roughness reaches Ra1.6, and the effective processing depth of the groove wall reaches 210mm. A ∅70 alloy-insulated milling cutter is selected, and the shank is roughened to increase rigidity. During processing, allowance is left for imitation finishing. The specific process route is as follows: ① Use a ∅70 drill bit to drill through the bottom hole of the waist groove side wall, and use a boring tool to expand and bore to ∅80.2; ② Use a ∅50 square shoulder milling cutter to rough mill the side wall of the waist groove, leaving a single-side 0.5mm smoothing allowance; ③Recheck the workpiece coordinate system and use ∅70X110L alloy milling cutter to simulate fine milling For the side wall, check the cross-sectional dimensions of the slot in sections to see if there is any taper. If there is a taper deviation, the cutting method needs to be corrected. ④ Fine milling 80 width to the drawing requirements, the processing must be poured with coolant, the milling method is down milling, after the processing is completed, check the straightness of the groove wall, check the position of the groove, and confirm that the symmetry meets 0.08mm.

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