A lathe axis positioning tool

Abstract

This utility model discloses a lathe spindle alignment fixture, relating to the field of lathe machining. It is suitable for unconventional clamping of diverse products and for rework of products with excessive coaxiality and circular runout, solving problems caused by multiple clamping errors and inconsistent positioning dimensions from previous processes. The fixture includes a base, a main body, at least three adjusting bolts, and a movable dial indicator with magnetic attraction. The base is fixed to the lathe chuck and connected to the main body via the adjusting bolts. The main body is equipped with a clamping device and a positioning reference surface with tightened tolerances, and the clamping position is aligned with the workpiece for machining. By tightening the adjusting bolts and monitoring with the dial indicator, the concentricity of the main body and the spindle can be ensured, and the workpiece runout can be ≤0.01mm. The base is universal, the main body is adjustable, the cost is low, it is suitable for shaft-type and thin-walled parts, avoids clamping damage, solves batch rework issues due to excessive tolerances, and is suitable for wide application.

Description

Technical Field

[0001] This utility model belongs to the field of auxiliary tooling technology for mechanical processing, and specifically relates to a lathe fixed axis alignment tooling. Background Technology

[0002] In lathe machining, especially for high-precision sealing conical parts for aerospace products, the requirements for coaxiality and circular runout are extremely high, requiring a circular runout of ≤0.02mm for the sealing conical surface. However, in actual production, traditional machining methods have significant technical defects. Conventional machining relies on the soft or hard jaws of the machine tool chuck to directly clamp the parts. The parts need to be disassembled midway for dimensional measurement, and re-clamping can easily cause clamping errors due to the offset of the positioning datum, resulting in the inability to guarantee the coaxiality and circular runout accuracy of the parts compared to the initial clamping. For example, in the machining of sealing conical surfaces for a certain aerospace product, nearly 1,000 products faced the risk of batch scrapping due to the aforementioned errors, resulting in serious economic losses.

[0003] Existing technologies do not specifically control the dimensional tolerances of the clamping and positioning surfaces. The positioning reference dimensions of the parts in the previous machining process are prone to deviation. For example, when the designed diameter of the arc-shaped clamped part is 20mm, the actual machining dimension may fluctuate by ±0.05mm, or be offset upwards or downwards. At the same time, traditional tooling cannot adjust the center height of the parts. The distance from the center height to the ground has inherent errors that cannot be corrected, making it difficult to ensure that the parts and the machine tool spindle are collinear, i.e., the generatrix coincides, further aggravating the problem of poor dimensional consistency.

[0004] Traditional tooling is mostly designed for specific purposes, and one tooling can only correspond to parts with a single structure, which cannot meet the unconventional clamping requirements of diverse products. Moreover, there is a lack of standardized control over clamping gaps and clamping force during clamping. Either the gaps are too large, causing the parts to wobble, or the fit is too tight, causing damage to the parts. At the same time, the tooling is prone to wear during processing because there is no effective positioning reference, which further affects the processing accuracy.

[0005] In response to the pain points of "large clamping error, poor positioning consistency and insufficient adaptability" in the existing technology, there is an urgent need to design an auxiliary tooling that is flexibly adjustable, has high positioning accuracy and is compatible with a variety of parts, so as to solve the problem of rework of out-of-tolerance products, avoid batch scrapping, and meet the high-precision clamping requirements of diverse products. Utility Model Content

[0006] The purpose of this invention is to solve the problems of the prior art and provide a lathe fixed axis alignment tool.

[0007] To solve the technical problem, the technical solution of this utility model is as follows:

[0008] A lathe spindle alignment fixture, comprising a lathe chuck and a tool holder, characterized in that it includes a base, a main body, at least three adjusting bolts, and a dial indicator with magnetic attraction; one end of the base is fixed to the lathe chuck, and the other end of the base is connected to one end of the main body via adjusting bolts; the other end of the main body is used to clamp the product to be processed; the gap between the base and the soft or hard jaws of the lathe chuck is 0.1–0.2 mm; a through hole is formed in the middle of the base from one end to the other, and an integrally formed protruding hollow screw post is provided at the first through hole at the end of the base connected to the lathe chuck; at least three through adjusting bolt holes are evenly formed along the circumference of the base's ring; the main body is a disc structure, and the end of the main body near the base has threaded holes that correspond one-to-one with and fit the adjusting bolt holes; the adjusting bolts pass through the adjusting bolt holes of the base and are threadedly engaged with the threaded holes of the main body, so that the base and the main body form a... The fixture has a split structure; the other end of the main body is equipped with a clamping device for clamping the product to be processed, and the main body is equipped with a positioning reference surface for positioning the product to be processed. The dimensional tolerance of the positioning reference surface is tightened. The split structure is used to adjust the center height of the product to be processed to a generatrix that is collinear with the axis of the machine tool spindle. The dial indicator is mounted on the machine tool holder and is movable. By pressing the dial indicator on the complete rotation diameter of the main body or the return reference diameter of the product to be processed, the runout of the main body or the product to be processed is monitored. By turning the adjusting bolt, the concentricity of the main body and the machine tool spindle and the runout of the product to be processed are controlled within 0.01mm. This fixture is suitable for scenarios where the positioning dimensions of the product to be processed in the previous process are inconsistent. The positioning dimensions of the product to be processed can be compensated and adjusted by turning the adjusting bolt. It is also suitable for clamping shaft-type, thin-walled parts and parts that need to be reworked for coaxiality and excessive circular runout.

[0009] Preferably, the number of adjusting bolts is three, and the three adjusting bolts are evenly distributed at equal intervals along the circumference of the base.

[0010] Preferably, one end of the main body clamping the product to be processed is provided with a semi-circular arc protrusion integrally formed therewith. The clamping device includes a pressure plate, a positioning pin, and an internal hexagonal bolt. The inner arc surface of the semi-circular arc protrusion constitutes the positioning arc surface of the product to be processed. This positioning arc surface is part of the positioning reference surface, and its dimensional tolerance requirements are tightened. The product to be processed is positioned by fitting against the positioning arc surface. The pressure plate is Ω-shaped, and its two ends correspond one-to-one with the two ends of the semi-circular arc protrusion. The pressure plate is fixedly connected to the semi-circular arc protrusion by the positioning pin to form a clamping circular hole for clamping the product to be processed. The single-sided fitting clearance between the clamping circular hole and the clamped position of the product to be processed is 0.005~0.015mm. The semi-circular arc... Each end of the protrusion has a first positioning pin hole adapted to the positioning pin, and each end of the pressure plate has a second positioning pin hole adapted to the positioning pin. The positioning pin passes through the second positioning pin hole and is installed in the first positioning pin hole to limit the relative displacement between the product to be processed and the main body. The pressure plate also has a first hexagonal bolt hole at each end, which is located between the second positioning pin hole and the end of the pressure plate. Each end of the semi-arc protrusion has a second hexagonal bolt hole adapted to the hexagonal bolt at each end, corresponding to the first hexagonal bolt hole. The hexagonal bolt passes through the first hexagonal bolt hole and is installed in the second hexagonal bolt hole to press and fix the pressure plate on the semi-arc protrusion, thereby pressing the product to be processed on the positioning arc surface.

[0011] Preferably, when the clamped part of the product to be processed is a planar structure, the shape of the pressure plate is replaced with a straight planar rectangle. The two ends of the straight planar rectangle pressure plate are still provided with second positioning pin holes and first internal hexagonal bolt holes, which cooperate with the semi-arc protrusion to realize the planar clamping and positioning of the product to be processed.

[0012] Preferably, the semi-circular raised positioning arc surface is adapted to the arc-shaped clamping part of the product to be processed. When the design size of the arc-shaped clamping part of the product to be processed is a preset value, such as a diameter of 20mm, and the actual processing size has a deviation, such as ±0.05mm, the deviation can be compensated by adjusting the screw to ensure that the product to be processed is concentric with the machine tool spindle.

[0013] Preferably, when the product to be processed needs to be clamped by threaded engagement, the main body is replaced by a disc with a threaded hole in the middle. The inner wall of the threaded hole constitutes the positioning reference surface of the product to be processed. The dimensional tolerance requirements of this positioning reference surface are tightened. The product to be processed is installed on the main body by engaging with the internal thread of the threaded hole.

[0014] Preferably, when the base is fixed on the lathe chuck, the clamping force of the chuck is adjusted to 1.5MPa by the machine tool pressure gauge, and the large end face of the base is exposed to light, that is, the large end face is flat and unobstructed.

[0015] Preferably, the dial indicator monitoring process includes two steps: First, when the main body is concentric with the machine tool spindle, press the dial indicator onto the complete rotation diameter of the main body, manually rotate the machine tool spindle, observe the dial indicator runout value, and tighten the adjusting bolts until the runout value is ≤0.01mm, then tighten the adjusting bolts in sequence; Second, after clamping the product to be processed, press the dial indicator onto the return reference diameter of the product to be processed, observe the dial indicator runout value, if the runout value is >0.01mm, slightly loosen the adjusting bolts, gently tap the position of the main body corresponding to the high value of the dial indicator with a rubber mallet, monitor again and tighten the adjusting bolts until the runout value is ≤0.01mm, tighten the adjusting bolts one by one and retest to confirm before starting processing.

[0016] Preferably, the clamping device of the main body and the clamping position of the product to be processed are manufactured by matching processing to ensure that the clamping device and the clamping position of the product to be processed fit tightly, avoid crushing of the product to be processed during clamping, and ensure clamping stability.

[0017] Preferably, the base of this tooling is a universal component, and the main body can be adaptively adjusted according to the structural characteristics of the product to be processed, such as the shape and size of the clamped part. The tooling is made of ordinary steel, such as scrap, which is low in cost and easy to operate. After processing, the adjusting bolts are removed, the base is separated from the main body, and the separated parts are oil-sealed to prevent rust.

[0018] Compared with the prior art, the advantages of this utility model are:

[0019] (1) This utility model fundamentally solves the pain point of "mid-process disassembly for measurement and clamping errors caused by multiple clamping" in the prior art by adopting a split structure of "base + main body + adjusting bolts" and a precise adjustment design. It realizes the clamping and alignment of shaft and thin-walled parts, solves the error between the product after re-clamping and the first clamping, and through the monitoring of three adjusting bolts and dial indicator, the runout of the main body and the machine tool spindle and the runout of the parts can be controlled within 0.01mm, ultimately achieving a high repeatability and ensuring that stable accuracy can be maintained after multiple clampings.

[0020] (2) On the one hand, this utility model can cover unconventional clamping and out-of-tolerance product rework scenarios, ensuring that the reworked products are qualified and avoiding batch scrapping; it can also be extended to various toolings, suitable for various products, and widely used in units. On the other hand, it has the ability to compensate for the reference: for cases where the reference positioning dimensions of the previous process are inconsistent, such as the part's arc design diameter is 20mm but the actual size is too high or too low, the positioning deviation can be compensated by slightly loosening the adjusting bolts, tapping with a rubber mallet, etc., to ensure the final processing accuracy; at the same time, the base is a universal part, and only the main body needs to be adjusted according to the product structure, further improving the adaptability and flexibility.

[0021] (3) This utility model ensures stable and compliant machining accuracy through multi-dimensional precision control design: First, the positioning reference surface is strictly controlled, and the main body clamping position and the part clamping position are machined together, with the single-sided fitting gap controlled at 0.005 to 0.015 mm to ensure tight clamping of the parts; Second, the base installation accuracy is controlled, with the gap between the base and the soft or hard jaws of the lathe chuck limited to 0.1 to 0.2 mm, and the clamping force is adjusted to 1.5 MPa by the machine tool pressure gauge to avoid base offset affecting concentricity; Third, dynamic monitoring and adjustment are implemented, with the use of a movable dial indicator with magnetic attraction to monitor runout in real time, ensuring that the accuracy after adjustment meets the requirement of within 0.01 mm, fully meeting the stringent standards for coaxiality and circular runout of shafts, thin-walled parts, and aerospace products.

[0022] (4) This utility model ensures that the clamping position of the main body and the clamping position of the part are 0.005 to 0.015 mm on one side, which can not only ensure that the part is clamped tightly and that the product is concentric with the spindle, but also avoid the crushing damage caused by excessive clamping. At the same time, when clamping, the part is fixed by pressure plate and positioning pin, such as the Ω-shaped pressure plate and the semi-arc protrusion to form a clamping round hole, which can limit the relative displacement of the part and prevent scratches or deformation caused by the shaking of the part during processing, thus taking into account both clamping stability and part protection.

[0023] (5) In terms of cost, this tooling has no material requirements. Ordinary materials and scraps can be processed without special materials or complex processes, which significantly reduces manufacturing costs. In terms of operation, the overall process is simple and easy to understand: only boring, adjusting clamping force, tightening adjusting bolts, dial indicator monitoring, and clamping parts are required. No professional or complex skills are required, which is in line with the design intention of simple operation. In terms of maintenance, after the product is processed, only three adjusting bolts need to be removed in sequence, the main body and the base can be separated and oil-sealed to prevent rust. The maintenance process is convenient and reduces subsequent maintenance costs. Attached Figure Description

[0024] Figure 1 A schematic diagram of the structure of Embodiment 2 of this utility model;

[0025] Figure 2 A schematic diagram of the structure of Embodiment 3 of this utility model;

[0026] Figure 3 A cross-sectional view of Embodiment 2 of this utility model;

[0027] Figure 4 A schematic diagram of the structure for clamping the processed product in Embodiment 2 of this utility model;

[0028] Figure 5 A cross-sectional view of the product being processed in Embodiment 2 of this utility model;

[0029] Figure 6Left view of the base of Embodiment 1 of this utility model;

[0030] Figure 7 AA view of the base of Embodiment 1 of this utility model;

[0031] Figure 8 A schematic diagram of the main structure of Embodiment 2 of this utility model;

[0032] Figure 9 Left view of the main body of Embodiment 2 of this utility model;

[0033] Figure 10 A schematic diagram of the structure of the pressure plate in Embodiment 2 of this utility model;

[0034] Explanation of reference numerals in the attached figures:

[0035] 1. Base; 2. Main body; 3. Adjusting bolts;

[0036] 101. First through hole; 102. Adjusting bolt hole; 103. Nut hole; 201. Threaded hole; 203. Semi-arc protrusion; 204. Threaded hole post; 2031. Pressure plate; 20311. Second locating pin hole; 2033. Clamping round hole; 2034. First locating pin hole; 2035. First hexagonal socket bolt hole; 2036. Second hexagonal socket bolt hole. Detailed Implementation

[0037] The specific embodiments of this utility model are described below with reference to examples:

[0038] It should be noted that the structures, proportions, sizes, etc. shown in this specification are only used to complement the content disclosed in the specification for those skilled in the art to understand and read, and are not intended to limit the conditions under which this utility model can be implemented. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and purposes that this utility model can produce, should still fall within the scope of the technical content disclosed in this utility model.

[0039] Example 1

[0040] like Figure 1 and Figure 2As shown, a lathe fixed-axis alignment fixture is provided, which includes a lathe chuck and a machine tool holder. The fixture comprises a base 1, a main body 2, at least three adjusting bolts 3, and a dial indicator with magnetic attraction. One end of the base 1 is fixed to the lathe chuck, and the other end of the base 1 is connected to one end of the main body 2 via adjusting bolts 3. The other end of the main body 2 is used to clamp the product to be processed. The gap between the base 1 and the soft or hard jaws of the lathe chuck is 0.1–0.2 mm. A through hole 101 is formed in the middle from one end to the other on the base 1, and an integrally formed protruding hollow screw post is provided at the first through hole 101 at the end of the base 1 connected to the lathe chuck. At least three through adjusting bolt holes 102 are evenly formed along the circumference of the annulus of the base 1. The main body 2 has a disc structure, and a threaded hole 201 corresponding to and adapted to the adjusting bolt holes 102 is provided at the end of the main body 2 near the base 1. The adjusting bolts 3 pass through the adjusting bolt holes 102 of the base 1 and are connected to the threaded bolts 201 of the main body 2. The 201 threaded hole allows the base 1 and the main body 2 to form a split structure. The other end of the main body 2 is equipped with a clamping device for clamping the product to be processed, and the main body 2 is equipped with a positioning reference surface for positioning the product to be processed. The dimensional tolerance requirements of this positioning reference surface are tightened. The split structure is used to adjust the center height of the product to be processed to a generatrix that is collinear with the axis of the machine tool spindle. The dial indicator is mounted on the machine tool holder and is movable. By pressing the dial indicator on the full rotation diameter of the main body 2 or the return reference diameter of the product to be processed, the runout of the main body 2 or the product to be processed is monitored. By turning the adjusting bolt 3, the concentricity of the main body 2 and the machine tool spindle and the runout of the product to be processed are controlled within 0.01mm. This fixture is suitable for scenarios where the positioning dimensions of the product to be processed in the previous process are inconsistent. The positioning dimensions of the product to be processed can be compensated and adjusted by turning the adjusting bolt 3. It is also suitable for clamping shaft-type, thin-walled parts and parts that need to be reworked for coaxiality and excessive circular runout.

[0041] This tooling is made of common materials, and can be processed from scraps, resulting in low cost and simple operation.

[0042] Preferably, the number of adjusting bolts 3 is three, and the three adjusting bolts 3 are evenly distributed at equal intervals along the circumference of the base 1.

[0043] Preferably, when the base 1 is fixed on the lathe chuck, the clamping force of the chuck is adjusted to 1.5MPa by the machine tool pressure gauge, and the large end face of the base 1 is exposed to light, that is, the large end face is flat and unobstructed.

[0044] Preferably, the dial indicator monitoring process includes two steps: First, when adjusting the main body 2 to be concentric with the machine tool spindle, press the dial indicator on the complete rotation diameter of the main body 2, manually rotate the machine tool spindle, observe the dial indicator runout value, tighten the adjusting bolts 3 until the runout value is ≤0.01mm, and then tighten the adjusting bolts 3 in sequence; Second, after clamping the product to be processed, press the dial indicator on the return reference diameter of the product to be processed, observe the dial indicator runout value, if the runout value is >0.01mm, slightly loosen the adjusting bolts 3, gently tap the position of the main body 2 corresponding to the high value of the dial indicator with a rubber mallet, monitor again and tighten the adjusting bolts 3 until the runout value is ≤0.01mm, tighten the adjusting bolts 3 one by one and retest to confirm before starting processing.

[0045] Preferably, the clamping device of the main body 2 is manufactured in a matching manner with the clamping position of the product to be processed, so as to ensure that the clamping device and the clamping position of the product to be processed fit tightly, avoid crushing of the product to be processed during clamping, and ensure clamping stability.

[0046] Example 2

[0047] Based on Example 1, Example 2 is preferably provided. One end of the main body 2 that clamps the product to be processed is provided with a semi-circular protrusion 203 integrally formed therewith. The clamping device includes a pressure plate 2031, positioning pins, and hexagonal bolts. The inner arc surface of the semi-circular protrusion 203 constitutes the positioning arc surface of the product to be processed. This positioning arc surface is part of the positioning reference surface, and its dimensional tolerance requirements are tightened. The product to be processed is positioned by fitting against the positioning arc surface. The pressure plate 2031 is Ω-shaped, and its two ends correspond one-to-one with the two ends of the semi-circular protrusion 203. The pressure plate 2031 is fixedly connected to the semi-circular protrusion 203 through positioning pins to form a clamping hole 2033 for clamping the product to be processed. The single-sided clearance between the clamping hole 2033 and the clamped position of the product to be processed is 0.005–0.015 mm. Each end of the semi-circular protrusion 203… A first positioning pin hole 2034 adapted to a positioning pin is provided. Each end of the pressure plate 2031 is provided with a second positioning pin hole 20311 adapted to a positioning pin. The positioning pin passes through the second positioning pin hole 20311 and is installed in the first positioning pin hole 2034 to limit the relative displacement between the product to be processed and the main body 2. The two ends of the pressure plate 2031 are also provided with a first hexagonal bolt hole 2035, which is located between the second positioning pin hole 20311 and the end of the pressure plate 2031. Each end of the semi-arc protrusion 203 is provided with a second hexagonal bolt hole 2036 adapted to a hexagonal bolt, corresponding to the first hexagonal bolt hole 2035. The hexagonal bolt passes through the first hexagonal bolt hole 2035 and is installed in the second hexagonal bolt hole 2036 to press and fix the pressure plate 2031 on the semi-arc protrusion 203, thereby pressing the product to be processed on the positioning arc surface.

[0048] Preferably, when the clamped part of the product to be processed is a planar structure, the shape of the pressure plate 2031 is replaced with a "I"-shaped planar rectangle. The two ends of the "I"-shaped planar rectangle pressure plate are still provided with a second positioning pin hole 20311 and a first internal hexagonal bolt hole 2035, which cooperate with the semi-arc protrusion 203 to realize the planar clamping and positioning of the product to be processed.

[0049] Preferably, the positioning arc surface of the semi-arc protrusion 203 is adapted to the arc-shaped clamping part of the product to be processed. When the design size of the arc-shaped clamping part of the product to be processed is a preset value, such as a diameter of 20mm, and the actual processing size has a deviation, such as ±0.05mm, the deviation can be compensated by adjusting the screw 3 to ensure that the product to be processed is concentric with the machine tool spindle.

[0050] Example 3

[0051] Based on Example 1, Example 3 is carried out. When the product to be processed needs to be clamped by threaded engagement, the main body 2 is replaced by a disc with a threaded hole post 204 in the middle. The inner wall of the threaded hole post 204 constitutes the positioning reference surface of the product to be processed. The dimensional tolerance requirements of the positioning reference surface are tightened. The product to be processed is installed on the main body 2 by engaging with the internal thread of the threaded hole post 204.

[0052] The operation procedure for the lathe fixed axis alignment fixture is as follows:

[0053] (1) First, bore the soft or hard jaws of the lathe chuck to ensure that the gap between the bore diameter and the clamping cylinder of the base is controlled at 0.1 to 0.2 mm to ensure the compatibility between the base and the chuck; install one end of the base on the lathe chuck and adjust the clamping force of the chuck to 1.5 MPa by using the machine tool pressure gauge. At the same time, ensure that the large end face of the base is "sunlight", that is, the large end face is flat and unobstructed, without any excess protrusions or impurities that affect the installation stability.

[0054] (2) Take the main body and thread the three adjusting bolts through the adjusting bolt holes evenly distributed circumferentially on the base ring, and connect them to the corresponding threaded holes at the end of the main body near the base to complete the initial assembly of the base and the main body; fix the magnetic dial indicator on the machine tool holder, the dial indicator can move, press the dial indicator needle on the complete rotation diameter of the main body; manually rotate the machine tool spindle and observe the runout value of the dial indicator, and gradually adjust the position of the main body by turning the three adjusting bolts until the runout value of the main body and the machine tool spindle displayed by the dial indicator is controlled within 0.01mm; after confirming that the runout accuracy meets the standard, tighten all adjusting bolts in sequence to complete the concentricity calibration of the main body and the machine tool spindle;

[0055] (3) The end of the main body used to clamp the product to be processed is precision bored. It is necessary to ensure that the clamping position of the main body after precision boring is matched with the clamping position of the part by a matching machining method. The single-sided fitting gap between the two is controlled at 0.005 to 0.015 mm to ensure that the subsequent parts can fit tightly, ensuring coaxiality and avoiding damage to the parts.

[0056] (4) Place the product to be processed into the clamping position of the main body, and fix the part by using a pressure plate, such as an Ω-shaped pressure plate or a straight rectangular pressure plate, in conjunction with the positioning pins. The positioning pins pass through the second positioning pin hole of the pressure plate and the first positioning pin hole of the semi-circular protrusion of the main body to limit the relative displacement between the part and the main body; then use hex bolts to pass through the first hex bolt hole of the pressure plate and the second hex bolt hole of the main body to press the pressure plate tight, thus completing the part fixing; move the dial indicator on the machine tool tool holder and press the indicator needle on the product to be processed. Reinstall the machine tool on the reference diameter; manually rotate the machine tool spindle again and observe the dial indicator runout: if the runout value is ≤0.01mm, the accuracy meets the standard, and the machine tool can be started directly for processing; if the runout value is >0.01mm, first slightly loosen the three adjusting bolts, and gently tap the position corresponding to the high value of the dial indicator on the main body with a rubber mallet, observing the dial indicator value while tapping, until the runout value is ≤0.01mm; then tighten the adjusting bolts one by one, and re-measure the runout value. Only after confirming that the accuracy is stable and meets the standard can processing begin;

[0057] (5) After the product is processed, first remove the internal hex bolts and positioning pins used to fix the parts, remove the pressure plate and take out the processed product; then remove the three adjusting bolts connecting the base and the main body in sequence, and separate the base from the main body; finally, seal the separated base, main body, adjusting bolts and other parts with oil to prevent the parts from rusting and facilitate subsequent reuse.

[0058] Example 4

[0059] Example 4 uses the "rework of a sealing cone surface of an aerospace product" as an application scenario. Due to multiple clamping errors during the early processing of this product, the circular runout of the sealing cone surface exceeded the tolerance. The design requirement was ≤0.02mm, but the actual deviation was 0.03-0.05mm. Nearly 1,000 pieces were to be reworked. High-precision rework was achieved using the fixed axis core alignment fixture of this lathe. The specific implementation process is as follows:

[0060] I. Preparations before implementation: Specifications of tooling components and parts to be processed

[0061] Tooling component specifications

[0062] Base 1: Made of ordinary 45# steel, the whole is a circular structure with an outer diameter of 120mm and an inner diameter of 50mm. A through hole 101 is opened in the middle. The first through hole at the end of the lathe chuck is integrally formed with a hollow protruding screw post with an outer diameter of 60mm and a height of 15mm. Three Φ12mm adjusting bolt holes 102 are opened at equal intervals along the circumference of the base ring, with the center of the hole 20mm away from the outer circle of the base.

[0063] Main body 2: Also made of 45# steel, it is a disc with a diameter of 120mm and a thickness of 30mm. Three M12 threaded holes 201 are opened near the base to match the adjusting bolt holes 102. The end away from the base is integrally formed with a semi-circular protrusion 203. The inner arc diameter of the protrusion matches the diameter of the cylindrical clamping section of the aerospace product to be repaired, which is Φ50mm. One Φ8mm first positioning pin hole 2034 and one M10 second internal hex bolt hole 2036 are opened at each end of the protrusion.

[0064] Adjusting bolt 3: Select standard M12×30 hexagonal internal bolts, a total of 3 pieces; Matching pressure plate 2031 is an Ω-shaped structure adapted to a Φ50mm cylindrical surface, with two Φ8mm second positioning pin holes 20311 and one M10 first hexagonal internal bolt hole 2035 at each end; Positioning pins are Φ8×20 cylindrical pins, and hexagonal internal bolts are M10×25 standard parts.

[0065] Auxiliary tools: a dial indicator with magnetic attraction, measuring range 0-10mm, accuracy 0.001mm, rubber hammer, machine tool pressure gauge, boring tool.

[0066] Specifications of the product to be repaired: The main body of the aerospace product is a cylindrical part with a diameter of 80mm and a diameter of 150mm. One end is a cylindrical clamping section with a diameter of 50mm and a diameter of 30mm. The other end is a sealing cone surface to be repaired with a taper of 1:10. It is necessary to ensure that the circular runout of the sealing cone surface relative to the cylindrical clamping section is ≤0.01mm.

[0067] II. Tooling Installation and Concentricity Adjustment

[0068] The base is compatible with the lathe chuck for installation.

[0069] First, bore the soft jaws of the lathe three-jaw chuck. Set the bore diameter to 120mm to ensure that the gap between the soft jaws and the base holding cylinder is 0.15mm after boring.

[0070] Insert one end of the base into the chuck jaws, adjust the chuck clamping force to 1.5MPa using the machine tool pressure gauge, and check the large end face of the base with a ruler to ensure that the end face is flat, unobstructed, and without obvious skewing.

[0071] Assembly of main body and base and spindle concentricity calibration

[0072] Pass the three adjusting bolts 3 through the adjusting bolt holes 102 of the base and screw them into the threaded holes 201 of the main body. Do not tighten them yet, and complete the separate assembly of the base and the main body.

[0073] Fix the magnetic dial indicator to the machine tool holder, move the tool holder so that the dial indicator needle presses vertically on the outer diameter of the main body, Φ120mm, and set the preload to 1mm.

[0074] Manually and slowly rotate the machine tool spindle to 50 r / min and observe the dial indicator reading. The initial runout value is 0.03 mm. By turning the three adjusting bolts 3 one by one—turning a bolt clockwise moves the corresponding position of the main body closer to the spindle side, and turning it counterclockwise moves it away—gradually adjust the position of the main body. During this process, rotate the spindle and retest multiple times until the runout value of the main body displayed on the dial indicator is stabilized at 0.008 mm (≤0.01 mm).

[0075] Tighten the three adjusting bolts 3 in diagonal order, with each bolt tightening torque set to 30 N·m. Rotate the main shaft again to retest and confirm that the main body runout is still ≤0.01 mm, thus completing the concentricity calibration.

[0076] III. Precision boring of main body clamping position and parts clamping

[0077] Precision boring of main body clamping position

[0078] Replace the boring bar and perform precision boring on the inner arc surface of the semi-arc protrusion 203 of the main body. Set the boring diameter to 50.01mm. After machining, measure the single-sided gap between the inner arc surface and the cylindrical clamping section Φ50mm of the product to be repaired, and ensure that the gap is 0.005mm within the range of 0.005-0.015mm to ensure that the parts fit tightly when clamped and there is no risk of pressure damage.

[0079] Clamping and accuracy retesting of products awaiting repair

[0080] Insert the Φ50mm cylindrical clamping section of the product to be repaired into the inner arc surface of the semi-arc protrusion 203 of the main body, cover it with the Ω-shaped pressure plate 2031, align the second positioning pin holes 20311 at both ends of the pressure plate with the first positioning pin holes 2034 of the protrusion, and insert positioning pins to restrict the displacement of the parts.

[0081] Pass the hex bolt through the first hex bolt hole 2035 of the pressure plate and screw it into the raised second hex bolt hole 2036. Tighten the bolt with a torque of 25 N·m to complete the part fixing.

[0082] Move the machine tool tool holder so that the dial indicator needle presses on the Φ50mm cylindrical clamping section (reinstallation reference diameter) of the product to be repaired. Manually rotate the machine tool spindle and observe the dial indicator runout value—the initial runout is 0.012mm (slightly exceeding 0.01mm).

[0083] Slightly loosen the three adjusting bolts 3 (each by 1 / 4 turn), and gently tap the position on the main body corresponding to the high value of the dial indicator with a rubber mallet. The highest point of the dial indicator needle should be 0.012mm, corresponding to the right side of the main body. After each tap, rotate the main shaft to re-measure. After three fine adjustments, the dial indicator runout value stabilizes at 0.007mm. Tighten the adjusting bolts 3 again in diagonal order, and re-measure to confirm that the runout is ≤0.01mm, and the accuracy meets the standard.

[0084] IV. Product rework and tooling post-processing

[0085] Sealing cone surface rework

[0086] Replace the CNC turning tool with a tool tip radius of 0.2mm and set the machining parameters as follows: spindle speed 1500r / min, feed rate 0.08mm / r, depth of cut 0.1mm.

[0087] Start the machine tool and perform precision machining on the sealing cone surface of the product. During the machining process, keep the cutting fluid continuously cooling to avoid thermal deformation affecting the accuracy. After machining is completed, stop the spindle and use a dial indicator to re-measure the circular runout of the sealing cone surface. The value is 0.006mm, which meets the design requirements.

[0088] Tooling disassembly and maintenance

[0089] First, remove the locating pins and hex bolts, then remove the pressure plate 2031 and take out the processed product;

[0090] Unscrew the three adjusting bolts 3 in sequence to separate the main body 2 from the base 1. Wipe the mating surfaces of the two with a cotton cloth to remove iron filings and oil stains.

[0091] Apply anti-rust oil to the adjusting bolt holes 102 on the base, the threaded holes 201 on the main body, and the positioning pin holes. Store the tooling components separately for easy access next time.

[0092] V. Implementation Results

[0093] In this embodiment 4, the fixed-axis alignment fixture successfully completed the rework of 1,000 out-of-tolerance aerospace product sealing cone surfaces. After rework, the circular runout of the sealing cone surfaces of the products was stably controlled within the range of 0.005-0.01mm, with a pass rate of 100%, avoiding batch scrap. Moreover, the entire process of fixture assembly, adjustment and disassembly is completed within 10 minutes for each piece, which is simple to operate. At the same time, because ordinary steel scrap is used for processing, the manufacturing cost of a single set of fixtures is only 300-350 yuan, which significantly reduces the rework cost.

[0094] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

[0095] Many other changes and modifications can be made without departing from the concept and scope of this utility model. It should be understood that this utility model is not limited to the specific embodiments, and the scope of this utility model is defined by the appended claims.

Claims

1. A lathe fixed-axis alignment fixture, wherein the lathe is provided with a lathe chuck and a machine tool holder, characterized in that: The system includes a base (1), a main body (2), at least three adjusting bolts (3), and a dial indicator with magnetic attraction. One end of the base (1) is fixed to a lathe chuck, and the other end of the base (1) is connected to one end of the main body (2) via adjusting bolts (3). The other end of the main body (2) is used to clamp the product to be processed. A through hole (101) is opened in the middle from one end to the other on the base (1), and an integrally formed protruding hollow screw post is provided at the first through hole (101) at the end of the base (1) connected to the lathe chuck. At least three through adjusting bolt holes (102) are evenly opened in the circumference of the ring of the base (1). The main body (2) is a disc structure. The end of the main body (2) near the base (1) is provided with threaded holes (201) that correspond one-to-one with and fit the adjusting bolt holes (102). The bolt (3) passes through the adjusting bolt hole (102) on the base (1) and threadedly engages with the threaded hole (201) on the main body (2), so that the base (1) and the main body (2) form a split structure; the other end of the main body (2) is provided with a clamping device for clamping the product to be processed, and the main body (2) is provided with a positioning reference surface for positioning the product to be processed; the split structure is used to adjust the center height of the product to be processed to a generatrix that is collinear with the axis of the machine tool spindle; the dial indicator is set on the machine tool tool holder and is movable. By pressing the dial indicator on the complete rotation diameter of the main body (2) or the reloading reference diameter of the product to be processed, the runout of the main body (2) or the product to be processed is monitored, so that the concentricity of the main body (2) and the machine tool spindle and the runout of the product to be processed are controlled within 0.01mm by turning the adjusting bolt (3).

2. The lathe fixed axis alignment fixture according to claim 1, characterized in that: The number of the adjusting bolts (3) is three, and the three adjusting bolts (3) are evenly distributed at equal intervals along the circumference of the base (1).

3. The lathe fixed axis alignment fixture according to claim 1, characterized in that: The main body (2) has a semi-circular protrusion (203) integrally formed with the product to be processed at one end. The semi-circular protrusion (203) is equipped with a clamping device, which includes a pressure plate (2031), a positioning pin, and an internal hexagonal bolt. The inner arc surface of the semi-circular protrusion (203) constitutes the positioning arc surface of the product to be processed. This positioning arc surface is part of the positioning reference surface. The product to be processed is positioned by fitting against the positioning arc surface. The pressure plate ( The shape of plate (2031) is Ω-shaped. The two ends of plate (2031) correspond one-to-one with the two ends of the semi-circular protrusion (203). Plate (2031) is fixedly connected to the semi-circular protrusion (203) via locating pins to form clamping holes (2033) for clamping the product to be processed. Each end of the semi-circular protrusion (203) has a first locating pin hole (2034) adapted to the locating pin. The two ends of plate (2031) each... A second positioning pin hole (20311) is provided to fit the positioning pin. The positioning pin passes through the second positioning pin hole (20311) and is installed in the first positioning pin hole (2034) to limit the relative displacement between the product to be processed and the main body (2). The pressure plate (2031) is also provided with first hexagonal bolt holes (2035) at both ends. The first hexagonal bolt holes (2035) are located between the second positioning pin hole (20311) and the pressure plate (2031). Between the ends, each end of the semi-circular protrusion (203) is provided with a second hexagonal bolt hole (2036) that is adapted to the hexagonal bolt, corresponding to the first hexagonal bolt hole (2035). The hexagonal bolt passes through the first hexagonal bolt hole (2035) and is installed in the second hexagonal bolt hole (2036) to press and fix the pressure plate (2031) on the semi-circular protrusion (203), thereby pressing the product to be processed on the positioning arc surface.

4. The lathe fixed axis alignment fixture according to claim 3, characterized in that: When the clamped part of the product to be processed is a planar structure, the shape of the pressure plate (2031) is replaced by a "I"-shaped planar rectangle. The two ends of the "I"-shaped planar rectangle pressure plate are still provided with a second positioning pin hole (20311) and a first internal hexagonal bolt hole (2035), which cooperate with the semi-arc protrusion (203) to realize the planar clamping and positioning of the product to be processed.

5. A lathe fixed axis alignment fixture according to claim 3, characterized in that: The single-sided gap between the clamping hole (2033) and the clamping position of the product to be processed is 0.005 to 0.015 mm.

6. The lathe fixed axis alignment fixture according to claim 1, characterized in that: When the product to be processed needs to be clamped by threaded engagement, the main body (2) is replaced by a disc with a threaded hole post (204) in the middle. The inner wall of the threaded hole post (204) forms the positioning reference surface of the product to be processed. The product to be processed is installed on the main body (2) by engaging with the internal thread of the threaded hole post (204).

7. A lathe fixed axis alignment fixture according to claim 1, characterized in that: The gap between the base (1) and the soft or hard jaws of the lathe chuck is 0.1 to 0.2 mm.

8. A lathe fixed axis alignment fixture according to claim 1, characterized in that: When the base (1) is fixed on the lathe chuck, the clamping force of the chuck is adjusted to 1.5MPa by the machine tool pressure gauge, and the large end face of the base (1) is exposed to light.

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