Milling and Drilling Tooling for Normal Holes on the Outer Conical Surface of Thin-Walled Conical Products and Its Processing Method

Abstract

A tool for drilling and milling normal holes on the outer conical surface of a thin-walled conical cylindrical product and a processing method thereof, comprising a base, a connecting column, a vertical plate, a telescopic adjustment rod, a rotary support table, a dividing circle assembly and a connecting disc. The telescopic adjustment rod is hingedly connected to the upper end of the column, and the rotary support and the vertical plate are fixed to the upper surface of the base. The rotary support table is connected to the upper ends of the telescopic adjustment rod and the vertical plate. The dividing circle assembly is mounted on the rotary support table. The present invention realizes the rapid and low-cost processing and manufacturing of normal circular holes of the conical section of thin-walled conical cylindrical parts on an ordinary desktop radial drilling machine, solves the problem of drilling and milling normal ordinary precision process holes on the outer conical surface of thin-walled conical cylindrical structural products represented by expansion section shells, reduces the dependence of such characteristic hole processing processes on CNC milling machine equipment resources, makes full use of ordinary drilling machines, has the advantages of low equipment investment, flexible use, and low processing cost, and realizes flexible and rapid processing of expansion section shell products in small batches and multiple varieties.

Description

Technical Field

[0001] The present invention relates to the mechanical processing industry, and in particular to a special device and a process method thereof, which can realize rapid leveling and positioning of the conical surface generatrix of a conical cylindrical thin-wall product and rapid drilling and milling processing using a radial drilling machine. Background Art

[0002] In recent years, my country's aviation and aerospace industries have experienced rapid development. During research and production, the demand for expansion shells featuring thin-walled, conical rotary structures (hereinafter referred to as expansion shells) has been increasing, showing a step-by-step annual growth trend. To meet scheduled delivery targets, our company, leveraging the diverse product models, varieties, and small batch deliveries, has implemented a mixed-line batch processing method. This has enhanced operational mobility and flexibility, ensuring on-time delivery of all models.

[0003] Figure 1 This is a schematic diagram of the expansion section housing. This product features a cylindrical rotating body at the small end and a thin-walled hollow cone at the large end. The small end's internal bore typically has internal threads of varying sizes, while the large end forms a "flare" shape with a cone angle θ relative to the central axis of rotation. To meet the lightweighting goal, the outer diameter and height are generally greater than 300mm. The product's walls are relatively thin, with a cone section wall thickness of 2-5mm.

[0004] In actual production, the overall structure of the expansion section shell is completed by semi-finishing and finishing machining, and 8 process holes are evenly distributed in the circumferential direction of the cone surface ( Figure 1 (The 5:1 magnified image at center I) primarily relies on four- and five-axis machining centers. However, with the increasing workload of various models on the production site, and the need for batch production of different models and specifications, machine tool processing resources are extremely tight. The existing processing method for tapered process holes is not only costly, but also severely squeezes the already saturated resources of precision CNC milling equipment. Specifically,

[0005] 1. Tapered normal holes are holes requiring average machining accuracy. Four- and five-axis CNC machining centers are fully capable of this task, while the five-axis machining centers used in production are precision machines, primarily used for semi-precision and precision milling of complex structural products. Using these expensive precision machines to produce these standard precision taper holes would be prohibitively expensive and uneconomical, resulting in a "big horse pulling a small cart" scenario.

[0006] 2. Because the cone angle θ and product specifications vary across different expansion housing models, machining on a conventional three-axis milling machine requires the design and manufacture of multiple sets of specialized positioning tooling for each cone angle and specification, resulting in prohibitively high tooling design costs. Furthermore, when the expansion housings being manufactured on-site are produced in small batches and on mixed lines for a variety of products, the tooling investment is high, the manufacturing cycle is long, and the replacement frequency is high, significantly reducing the flexibility and maneuverability of the production site.

[0007] Patent search results:

[0008] Patent 1: A conical surface drilling positioning device Application number: 20221829779.4

[0009] Difference: The above patent right protects a positioning device, which is to achieve static positioning and drilling and milling processing of the workpiece while it is fixed, which is completely different from the present embodiment.

[0010] Patent 2 Application No.: Indexing fixture for drilling holes on cones and inclined holes on cylinders Application No.: 201020627437.5

[0011] Differences: The above patent and this embodiment have different structures and the workpieces processed are completely different in features. This embodiment advocates a thin-walled conical cylindrical product. Summary of the Invention

[0012] In order to overcome the problems in the prior art of the expansion section shell product's conical surface specifications and diversified cone angles, which make it difficult to manufacture and process it quickly and at low cost on CNC machine tools, the present invention proposes a tool for drilling and milling normal holes on the outer cone surface of a thin-walled conical cylindrical product and a processing method thereof.

[0013] The tooling for drilling and milling normal holes on the outer conical surface of thin-walled conical cylindrical products proposed in the present invention comprises a base, a connecting column, a vertical plate, a telescopic adjustment rod, a rotary support platform, a dividing circle assembly, and a connecting disc. The telescopic adjustment rod is hingedly connected to the upper end of the connecting column. The vertical plate is fixed to the upper surface of the base, and the connecting column is fixed to one side of the vertical plate. The rotary support is located above the base, with one end of the bottom plate of the rotary support platform hingedly connected to the upper end of the telescopic adjustment rod, and the other end of the bottom plate is connected to the upper end of the vertical plate via a rotating shaft. The rotary support platform is capable of pitching and rotating, supported by the telescopic adjustment rod and the vertical plate. The dividing circle assembly is mounted on the upper surface of the rotary support platform via bearings. The connecting disc is connected to the dividing circle assembly in the dividing circle assembly. The rotary support platform includes a front bearing seat and a front bearing seat. A rotating shaft connected to the vertical plate is mounted on the lower surface of the rotary support platform, at one end of the dividing circle. A front bearing seat and a rear bearing seat are fixed to the upper surface of the base plate, with the front bearing seat positioned adjacent to one end of the indexing disc. Rolling bearings for mounting the indexing disc shaft of the indexing disc assembly are mounted on the upper surfaces of the front and rear bearing seats, respectively. The front bearing cover, rear bearing cover, and rear bearing plug cover secure the rolling bearings, while a rotatable transmission shaft with a stepped stop is mounted in the two rolling bearings.

[0014] The indexing disc assembly includes a indexing disc and a indexing disc drive shaft. One end of the drive shaft is fixed to the center hole of the indexing disc. The indexing disc has a convex shape and is evenly distributed with indexing tapered holes on its surface. The large-diameter end of the indexing disc serves as its connecting flange. The center of the indexing disc has a mounting hole for the indexing disc shaft.

[0015] When the indexing circle assembly is connected to the rotary support table, the indexing circle shaft is installed on the front bearing seat and the rear bearing seat of the rotary support table through bearings, and a indexing positioning plug is installed on the front bearing seat, and a compression spring is mounted on the indexing positioning pin, and the compression spring is located between the inner end surface of the indexing disc and the outer surface of the front bearing seat.

[0016] The telescopic adjustment rod is rod-shaped and includes a left-handed support ring, a right-handed support ring, a rotating support tube, and left-handed and right-handed locking nuts. The rotating support tube is a rotating body with threaded blind holes at both ends for mounting the left-handed and right-handed support rings, respectively. Locking nuts are mounted on the left-handed and right-handed support rings, respectively, to prevent axial movement of the left-handed and right-handed support rings. The outer ends of the left-handed and right-handed support rings are each U-shaped, forming connecting tabs that connect the ends of the telescopic adjustment rod to the connecting column and the rotating support platform, respectively.

[0017] The connecting disc is an annular plate. An axially protruding connecting sleeve is located on the outer end of the connecting disc. The outer circumferential surface of the connecting sleeve is a threaded surface for connecting to a conical cylindrical product. A through hole is located in the center of the connecting disc to mate with the indexing disc.

[0018] The specific process of using the drilling and milling tooling to process the normal hole on the outer conical surface of a thin-walled conical cylindrical product proposed by the present invention is:

[0019] Step 1: Install the connecting disc.

[0020] 1.1. Install the connecting disc onto the indexing disc. Insert the screws through the holes in the connecting disc and screw them into the threaded holes on the indexing disc. The clearance between the mating surfaces of the connecting disc and the indexing disc should be ≤0.06.

[0021] 1.2. Rotate the connecting disc and use a dial indicator to check the disc runout; the runout is less than the designed coaxiality accuracy of the expansion section product.

[0022] Step 2: Install the drilling and milling tooling:

[0023] Install the drilling and milling tool on the drilling machine table.

[0024] Step 3: Install the expansion section shell verification piece:

[0025] Put the small end of the expansion section shell verification piece onto the connecting disc.

[0026] Step 4: Adjust the telescopic adjustment rod:

[0027] Adjust the telescopic adjustment rod until the expansion section housing's generatrix is horizontal. Tighten the left-hand and right-hand locknuts to lock the telescopic adjustment rod. Adjust the drill tip so it is close to and aligned with the process hole on the calibration part. Lock the X and Y rocker arm coordinates on the horizontal plane of the drill press and tighten the work base.

[0028] Step 5: Process the first cone normal hole:

[0029] Drill and mill the first normal hole on the conical surface. The drilling and milling head downward speed is ≤ 1mm / s. Complete the machining of the first normal hole on the conical surface.

[0030] Step 6. Adjust the indexing disc to the position of the second cone normal hole:

[0031] Pull out the positioning pin of the indexing disc; loosen the positioning pin handle while rotating the indexing disc. When it slides to the position of the second cone normal hole, the positioning pin is quickly reset under the reaction of the compression spring and locks the indexing disc.

[0032] Step 7: Process the normal holes on each cone surface:

[0033] Repeat the process of step 5 to complete the processing of the second cone normal hole;

[0034] Repeat step 6 to adjust the indexing disc to the next normal hole position on the tapered surface.

[0035] The process of repeating step 5 and the process of repeating step 6 are looped to complete the processing of all normal holes on the conical surface of the product.

[0036] Step 8. Repeat steps 4 to 7 to complete the drilling and milling of the normal holes on the conical surfaces of the remaining products in this batch.

[0037] At this point, the processing of the normal hole on the outer cone surface of the thin-walled conical cylindrical product is completed.

[0038] Since the normal circular hole on the conical surface of the conical section of a thin-walled conical cylindrical part is a process hole with general processing accuracy, there is no need to over-rely on four-axis and five-axis machining machine resources, and there is no need to occupy ordinary three-axis milling machining centers that are overloaded with tasks. Therefore, the present invention proposes the idea and method of using a small bench drill and a small radial drilling machine to achieve rapid drilling and milling processing.

[0039] The present invention proposes a drilling and milling tool for machining the normal circular hole on the outer conical surface of the expansion section shell using a small bench drill and a small radial drilling machine, so as to realize the rapid and low-cost machining and manufacturing of the normal circular hole of the tapered section of a thin-walled conical cylindrical part on an ordinary bench radial drilling machine.

[0040] 1. By cleverly utilizing the positioning surface and internal thread surface features of the small end of the expansion section, and in accordance with the different thread sizes of the expansion section shells of different models, a quickly replaceable positioning disc is designed and manufactured. Through rapid tightening and end face positioning, the requirements of rapid positioning and clamping are met.

[0041] 2. In addition, during the tooling design process, a quickly replaceable positioning disc device was designed to better meet the universal requirements of the tooling body for "one machine with multiple uses".

[0042] 3. In addition, in response to the variability requirements of the cone angle θ of this type of product, the principle of connecting rod hinge structure is adopted to design and manufacture a cone angle continuous adjustment and locking device to ensure that the generatrix of the expansion section shell surface is always in a horizontal state during the actual processing process. During the processing, the drill bit performs drilling and milling in the vertical direction along the normal of the cone surface to ensure the processing position requirements of the hole.

[0043] 4. In combination with the circumferential uniform distribution of the product's conical surfaces, a simple indexing device that can be manually pulled out and disengaged and spring-compressed for self-locking positioning was designed and manufactured, innovatively realizing rapid indexing and positioning during product rotation.

[0044] 5. A method for measuring the horizontality of the expansion section cone's generatrix is proposed. This involves using a dial indicator for rotational alignment according to specific product requirements to ensure that the required rotational accuracy is met. During the horizontality adjustment process for the expansion section shell's outer cone generatrix, a portable leveling instrument is proposed for measuring and calibrating the horizontality of the expansion section shell's outer cone generatrix.

[0045] 6. The problem of repeated positioning during the expansion section housing replacement process has been resolved. First, the expansion section housing calibration piece used for tool calibration (the main features and specifications of the calibration piece are the same as the official product, and the conical surface is equipped with qualified process holes) is aligned and positioned on the drilling machine. After the tooling position and depression angle are adjusted and checked, the base is pressed or screwed, and the telescopic adjustment rod is locked in time. Subsequent products to be processed only need to be quickly tightened into place manually to ensure repeated positioning of the processed holes, meeting the requirements of rapid drilling and milling of conical surface holes in subsequent batches of products.

[0046] 7. A simple indexing disc and its mechanism components are designed. Simply pull out the positioning pin, rotate the workpiece, and automatically reset and lock it to complete the drilling and milling of the next hole. Repeating this process can achieve rapid indexing and processing of all process holes on the tapered surface.

[0047] If you need to process other expansion section products of different sizes, specifications and cone angles, you only need to replace the connecting disc and follow the above steps.

[0048] The tooling structure and processing method of the present invention have the following innovative effects:

[0049] 1. The principle of the planar connecting rod articulated motion structure is innovatively applied to the processing of expansion section shell products. Since the articulated structure has one plane rotational degree of freedom, it solves the problem of adjusting the horizontality of the expansion section shell surface.

[0050] 2. To ensure the required horizontality of the expansion section housing's generatrix, a rotatable, telescopic, and adjustable locking lever assembly with a locking function was designed. The adjustment mechanism utilizes a precision-fit threaded connection structure, ensuring precise and flexible extension and retraction of the lever. Furthermore, a locking nut ensures instant locking once the mechanism is adjusted into position, ensuring the outer cone generatrix of the expansion section housing remains horizontal, whether stationary or during drilling and milling.

[0051] 3. A simple rotary indexing mechanism was designed and manufactured. Because the process holes on the tapered surface of the expansion section are evenly distributed 360° around the circumference, a simple indexing mechanism was designed and manufactured. Eight tapered positioning pin holes were evenly distributed on the indexing disc. A rebound-type positioning pin with a matching taper on the small end was also manufactured to automatically lock the indexing disc using the spring's rebound force.

[0052] 4. The present invention solves the problem of drilling and milling normal precision process holes on the outer cone surface of thin-walled conical cylindrical structural products represented by expansion section shells, reduces the dependence of such characteristic hole processing processes on CNC milling machine equipment resources, and fully utilizes the advantages of ordinary drilling machine equipment such as low investment, flexible use, and low processing cost, thereby realizing flexible and rapid processing of expansion section shell products in small batches and multiple varieties. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 Schematic diagram of the expansion section shell structure of the present invention; wherein, Figure 1 a is the main view, Figure 1 b is the axonometric view, Figure 1 c is Figure 1 An enlarged view of position A on the a-axis.

[0054] Figure 2 This is a diagram showing the working principle of the drilling and milling tooling for the normal process holes on the conical surface of the expansion section shell.

[0055] Figure 3 It is an axonometric schematic diagram of the present invention.

[0056] Figure 4 It is a structural schematic diagram of the present invention.

[0057] Figure 5 is a schematic diagram of the base structure; Figure 5 a is the main view, Figure 5 b is the top view, Figure 5 The c is the axonometric view.

[0058] Figure 6 It is a structural diagram of the vertical plate.

[0059] Figure 7 : is a structural diagram of the telescopic adjustment rod assembly of the present invention, wherein: Figure 7 a is the main view, Figure 7 b is the top view, Figure 7 The c is the axonometric view.

[0060] Figure 8 It is a structural diagram of the rotary support table assembly.

[0061] Figure 9 It is a structural diagram of the indexing mechanism.

[0062] Figure 10 It is a structural diagram of the indexing positioning pin; among them, Figure 10 a is the main view, Figure 10 b is the axonometric drawing.

[0063] Figure 11 It is a structural diagram of the indexing disc; Figure 11 a is the main view, Figure 11 b is Figure 11 AA section view in a.

[0064] Figure 12 is a schematic diagram of the structure of the connected disks; Figure 12 The a is Figure 12 Right view of b.

[0065] In the figure: 1. Base; 2. Connecting column; 3. Vertical plate; 4. Telescopic adjustment rod; 5. Rotary support table; 6. Indexing circle assembly; 7. Connecting disc; 8. Left-handed support ring; 9. Left-handed locking nut; 10. Washer; 11 Rotating support cylinder; 12. Right-handed locking nut; 13. Right-handed support ring; 14. Flat key; 15. Front bearing cover; 16. Rolling bearing; 17. Transmission shaft; 18. Rear bearing cover; 19. Rear bearing plug cover; 20. Front bearing seat; 21. Rear bearing seat; 22. Positioning pin, 23. Indexing disc, 24. Limit nut, 25. Compression spring; 26. Indexing positioning tapered hole; 27. Connecting threaded hole; 28. Connecting through hole; 29. Connecting disc. DETAILED DESCRIPTION

[0066] This embodiment is a tool for drilling and milling normal holes on the outer conical surface of thin-walled, conical cylindrical products. It comprises a base 1, a connecting column 2, a vertical plate 3, a telescopic adjustment rod 4, a rotary support platform 5, a dividing mechanism 6, and a connecting disc 7. The telescopic adjustment rod is hingedly connected to the upper end of the connecting column.

[0067] The vertical plate 3 is fixed on the upper surface of the base, and a connecting column 2 is fixed on one side of the vertical plate 3. The swivel support platform 5 is located above the base, and one end of the bottom plate in the swivel support platform is hinged to the upper end of the telescopic adjustment rod 4, and the other end of the bottom plate is connected to the upper end of the vertical plate 3 through a rotating shaft; the swivel support platform 5 is supported by the telescopic adjustment rod and the vertical plate, and can perform pitch rotation. A dividing circle assembly 6 is installed on the upper surface of the swivel support platform through a bearing. The connecting disc 7 is connected to the dividing disc in the dividing circle assembly. The swivel support platform 5 includes a front bearing seat and a front bearing seat, wherein a rotating shaft connected to the vertical plate 3 is installed on the lower surface of the swivel support platform 5 at one end of the dividing disc. The front bearing seat and the rear bearing seat are fixed on the upper surface of the bottom plate, and the front bearing seat is close to one end of the dividing disc. Rolling bearings 16 for mounting the pitch circle shaft of the pitch circle assembly are mounted on the upper surfaces of the front and rear bearing seats, respectively. The front bearing cover 15, rear bearing cover 18, and rear bearing plug cover 19 are used to secure the rolling bearings 16. A rotatable drive shaft 17 with a stepped stop feature is mounted in the two rolling bearings 16. The indexing disc transmits its rotational motion to the drive shaft 17 via a flat key 14.

[0068] The dividing circle assembly 6 includes a dividing circle, a dividing circle transmission shaft 17, a compression spring and a positioning pin 22 for dividing. One end of the dividing circle transmission shaft 17 is fixed in the center hole of the dividing circle and is connected by a flat key 14. The dividing circle has a convex shape, and dividing tapered holes are evenly distributed on the surface of the dividing circle; the large diameter end of the dividing circle is the connecting flange of the dividing circle. There is a mounting hole for the dividing circle shaft in the center of the dividing circle. When the dividing circle assembly is connected to the rotary support platform 5, the dividing circle shaft is installed on the front bearing seat and the rear bearing seat of the rotary support platform through bearings, and a dividing positioning pin 22 is installed on the front bearing seat, and a compression spring 25 is installed on the dividing positioning pin, and the compression spring is located between the inner end face of the dividing circle and the outer surface of the front bearing seat.

[0069] The telescopic adjustment rod 4 is rod-shaped and includes a left-handed support ring 8, a right-handed support ring 13, a rotating support tube 11, a left-handed locking nut 9, a right-handed locking nut 12, and a washer. The rotating support tube is a rotating body with blind holes with threaded surfaces at both ends for mounting the left-handed and right-handed support rings, respectively. Locking nuts are mounted on the left-handed and right-handed support rings, respectively, to prevent axial movement of the left-handed and right-handed support rings. The outer ends of the left-handed and right-handed support rings are each U-shaped, forming connecting tabs that connect the ends of the telescopic adjustment rod to the connecting column 2 and the rotating support platform 5, respectively.

[0070] The connecting disc 7 is an annular plate. An axially protruding connecting sleeve is provided on the outer end face of the connecting disc. The outer circumferential surface of the connecting sleeve is a threaded surface for connecting to the conical cylindrical product. A through hole is provided in the center of the connecting disc to cooperate with the indexing disc.

[0071] In this embodiment, the structural features are described respectively through the figures.

[0072] Figure 3Middle: The bottom of the tooling base is typically equipped with positioning blocks to support, level, and solidify the entire punching tooling structure, ensuring proper placement and positioning of the tooling with respect to the worktable of a conventional drilling / milling machine. 3 is the vertical plate structure, a fixed component of the tooling that provides a fixed rotational fulcrum for the entire tooling movement. 2 is the connecting column, used to secure and connect the telescopic adjustment rod. 4 is the telescopic adjustment rod, which not only has telescopic adjustment capabilities but also features a self-locking length function, providing posture adjustment and locking for the product's outer conical working surface. 5 is the rotary support table, which ensures that the product has only one degree of freedom of rotation, meeting the rotation and positioning requirements for hole indexing. 6 is the replaceable indexing disc, whose indexing holes are related to the number of indexing holes on the product's conical surface, enabling indexing of the outer conical surface normal holes to a predetermined angular position. 7 is the quickly replaceable connecting disc, custom-designed to the specifications of the expansion section housing product, primarily used to connect and secure the expansion section housing product.

[0073] Figure 7 In the diagram, 8 is a left-hand support ring, and 13 is a right-hand support ring. Their inner holes are designed with standard left-hand and right-hand thread forms, respectively. 11 is a rotating support cylinder, and the threaded inner holes at both ends are designed with standard left-hand and right-hand thread forms, respectively, to achieve telescopic adjustment. 9 and 12 are standard left-hand and right-hand locking nuts, respectively, to ensure that the adjustment rod is locked immediately after telescopic adjustment.

[0074] Figure 8 It is a rotary support structure, including 14 flat keys, 15 front bearing cover, 16 bearing, 17 transmission shaft, 18 rear bearing cover, 19 rear bearing plug cover, 20 front bearing seat, 21 rear bearing seat

[0075] This embodiment also proposes a method for processing thin-walled conical cylindrical products using the outer conical surface normal hole drilling and milling tooling. The specific process is:

[0076] Step 1: Install the connecting disc.

[0077] 1.1. Install the connecting disc 7 onto the indexing disc 23. Insert four screws with spring washers through the holes in the connecting disc and screw them into the threaded holes on the indexing disc. Ensure that the mating surfaces are tightly fitted, with a clearance of ≤0.06.

[0078] 1.2. Rotate the connecting disc 7 and use a dial indicator to check the disc runout. The runout should be less than the designed coaxiality accuracy of the expansion section product.

[0079] Step 2: Install the drilling and milling tooling onto the drilling machine table.

[0080] Step 3: Screw the small end of the calibration expansion section housing verification piece into the connecting disc and install it in place. The structural features and specifications of the calibration expansion section housing verification piece are consistent with those of the workpiece to be processed.

[0081] Step 4: Adjust the telescopic adjustment rod until the expansion section housing's surface generatrix is horizontal. Tighten the left-hand and right-hand locknuts to lock the telescopic adjustment rod. Adjust the drill tip so that it is close to and aligned with the process hole of the calibration part. After confirming that the tool is correct, lock the X and Y rocker arm coordinates on the horizontal plane of the drill press and tighten the work base.

[0082] Step 5: Drill and mill a normal hole on the first cone surface. The drilling and milling head should move downward at a speed of ≤1 mm / s. Spray cutting fluid during machining. The first normal hole on the cone surface is machined.

[0083] Step 6. Pull out the positioning pin, rotate the indexing disk while loosening the positioning pin handle. When it slides to the position of the second cone normal hole, the positioning pin is quickly reset under the reaction of the compression spring and locks the indexing disk, completing the drilling and milling of the second cone normal hole.

[0084] Step 7. Repeat step 6 to complete the processing of all normal holes on the conical surface of the product.

[0085] Step 8. Repeat steps 4 to 7 to complete the drilling and milling of the normal holes on the conical surfaces of the remaining products in this batch.

[0086] At this point, the processing of the normal hole on the outer cone surface of the thin-walled conical cylindrical product is completed.

Claims

1. A tool for drilling and milling normal holes on the outer conical surface of a thin-walled conical cylindrical product, characterized in that: The invention comprises a base (1), a connecting column (2), a vertical plate (3), a telescopic adjustment rod (4), a rotary support platform (5), a pitch circle assembly (6) and a connecting disc (7); a telescopic adjustment rod is hinged on the upper end of the connecting column; the vertical plate is fixed on the upper surface of the base, and a connecting column (2) is fixed on one side of the vertical plate; the rotary support platform is located above the base, and one end of the bottom plate in the rotary support platform is hinged to the upper end of the telescopic adjustment rod (4), and the other end of the bottom plate is connected to the upper end of the vertical plate (3) through a rotating shaft; the rotary support platform (5) can be pitched and rotated under the support of the telescopic adjustment rod and the vertical plate; the pitch circle assembly (6) is installed on the upper surface of the rotary support platform through a bearing. ); the connecting disc (7) is connected to the indexing disc in the indexing circle assembly; the rotary support platform includes a front bearing seat and a front bearing seat, wherein a rotating shaft connected to the vertical plate (3) is installed on the lower surface of one end of the indexing disc on the rotary support platform; a front bearing seat and a rear bearing seat are fixed on the upper surface of the base plate, and the front bearing seat is close to one end of the indexing disc; a rolling bearing (16) for mounting the indexing circle rotating shaft in the indexing circle assembly is respectively provided on the upper surfaces of the front bearing seat and the rear bearing seat, a front bearing upper cover (15), a rear bearing upper cover (18), and a rear bearing plug cover (19) are used to fix the rolling bearings, and a rotatable transmission shaft (17) with a step stop feature is installed in the two rolling bearings (16); The indexing circle assembly (6) comprises a indexing disc and a indexing circle transmission shaft (17); one end of the transmission shaft is fixed in the center hole of the indexing disc; the indexing disc has a convex shape, and indexing tapered holes are evenly distributed on the disc surface of the indexing disc; the large diameter end of the indexing disc is a connecting flange of the indexing disc; the center of the indexing disc has a mounting hole for the indexing circle rotating shaft; When the indexing circle assembly is connected to the rotary support platform (5), the indexing circle shaft is installed on the front bearing seat and the rear bearing seat of the rotary support platform through bearings, and a indexing positioning pin (22) is installed on the front bearing seat, and a compression spring (25) is installed on the indexing positioning pin, and the compression spring is located between the inner end surface of the indexing disk and the outer surface of the front bearing seat; The telescopic adjustment rod (4) is rod-shaped and comprises a left-handed support ring (8), a right-handed support ring (13), a rotating support tube (11), a left-handed locking nut (9), and a right-handed locking nut (12); the rotating support tube is a rotating body, and has blind holes with threaded surfaces at both ends, respectively used to install the left-handed support ring and the right-handed support ring; locking nuts are respectively mounted on the left-handed support ring and the right-handed support ring, and the locking nuts are used to prevent the axial movement of the left-handed support ring and the right-handed support ring; the outer end heads of the left-handed support ring and the outer end heads of the right-handed support ring are respectively U-shaped grooves, forming connecting lugs for connecting the two ends of the telescopic adjustment rod to the connecting column (2) and the rotating support platform (5).

2. The tooling for drilling and milling normal holes on the outer conical surface of a thin-walled conical cylindrical product according to claim 1, characterized in that: The connecting disc (7) is in the shape of an annular plate; an axially protruding connecting sleeve is provided on the end face of the outer end of the connecting disc, and the outer circumferential surface of the connecting sleeve is a threaded surface for connecting with a conical cylindrical product; a through hole is provided at the center of the connecting disc to cooperate with the dividing disc.

3. A method for machining a normal hole on the outer conical surface of a thin-walled conical cylindrical product using the drilling and milling tool according to claim 1, characterized in that: The specific process is: Step 1, install the connecting disc; Install the connecting disc (7) onto the indexing disc (23); Step 2: Install the drilling and milling tooling: Installing the drilling and milling tooling on the drilling machine table; Step 3: Install the expansion section shell verification piece: Put the small end of the expansion section shell verification piece onto the connecting disc; Step 4: Adjust the telescopic adjustment rod: Adjust the telescopic adjustment rod until the busbar of the expansion section shell surface is horizontal; tighten the left-hand lock nut and the right-hand lock nut to lock the telescopic adjustment rod; adjust the drill tip so that it is close to and aligned with the process hole of the calibration piece; Lock the X and Y rocker arm coordinates on the horizontal plane of the drilling machine and press the work base; Step 5: Process the first cone normal hole: Drill and mill the first normal hole on the conical surface, with the drilling and milling head moving down at a speed of ≯1mm / s; complete the machining of the first normal hole on the conical surface; Step 6. Adjust the indexing disc to the position of the second cone normal hole: Pull out the indexing positioning pin; while rotating the indexing disc, loosen the indexing positioning pin handle. When it slides to the second cone normal hole position, the indexing positioning pin quickly resets under the reaction of the compression spring and locks the indexing circle. Step 7: Process the normal holes on each cone surface: Repeat the process of step 5 to complete the processing of the second cone normal hole; Repeat step 6 to adjust the indexing disc to the next cone normal hole position; Repeat the process of step 5 and step 6 in a loop to complete the processing of all normal holes on the conical surface of the product; Step 8. Repeat steps 4 to 7 to complete the drilling and milling of the normal holes on the remaining tapered surfaces of the products; At this point, the processing of the normal hole on the outer cone surface of the thin-walled conical cylindrical product is completed.

4. The method for machining a normal hole on the outer conical surface of a thin-walled conical cylindrical product according to claim 3, characterized in that: When installing the connecting disc: Ⅰ When installing the connecting disc to the indexing disc, insert the screw through the connecting disc through hole and screw it into the threaded hole on the indexing disc; the distance between the connecting disc and the indexing disc mating surface is ≤0.06; II. Rotate the connecting disc and detect the disc runout using a dial indicator; the runout is less than the designed coaxiality accuracy of the expansion section product.

5. The method for machining a normal hole on the outer conical surface of a thin-walled conical cylindrical product according to claim 3, characterized in that: When adjusting the telescopic adjustment rod, tighten the left-hand locking nut and the right-hand locking nut to lock the telescopic adjustment rod; adjust the drill tip so that it is close to and aligned with the process hole of the calibration piece; lock the X and Y rocker arms on the horizontal plane of the drilling machine and press the work base.

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