Drilling tool for machining of inclined hole of mandrel

Abstract

The utility model relates to a kind of drilling tool for core shaft inclined hole processing, including lathe workbench, the top surface of lathe workbench is respectively equipped with support adjusting block and support block, the top surface of support adjusting block and support block is integrally formed inclined surface of inclination;Inclined surface is equipped with fixed plate;The top surface of fixed plate is equipped with chuck, the inner hole of chuck is equipped with three concentric positioning keys, three concentric positioning keys are used to with core shaft adaptation clamping, for realizing the centering and clamping of core shaft.The top surface of fixed plate is also equipped with precision angle ruler, for detecting the included angle between fixed plate and lathe workbench top surface.The top surface angle of support adjusting block and support block is strictly matched with the included angle of core shaft inclined hole to be processed and core shaft axis, combined with the repeated calibration of precision angle ruler to fixed plate angle, ensure that inclined hole axis and drill bit axis are accurately aligned.Can realize the uniform clamping and coaxial centering of core shaft, avoid the processing deviation caused by stress deformation or deviation of core shaft.

Description

Technical Field

[0001] This utility model relates to a drilling fixture, and more particularly to a drilling fixture for machining oblique holes in a mandrel. Background Technology

[0002] In the field of machining, the mandrel, as a key component of the machine tool electric spindle, requires extremely high precision and efficiency in machining small oblique holes on its end face for gas sealing and cooling. Current technologies often face a dilemma in machining such oblique holes: while electrical discharge machining can guarantee accuracy, it is time-consuming and involves high equipment and consumable costs. Relying on multi-axis machine tools requires matching specific equipment stroke and precision, and also necessitates time-consuming machining program development, resulting in high barriers to entry and costs.

[0003] Meanwhile, existing oblique hole machining devices mostly focus on general angle adjustment or specific hole shape machining. For example, some solutions use a rotating body structure to adapt to oblique hole machining on three-axis machine tools, but they lack stability in centering and clamping for slender and precision parts such as mandrels. There are also methods that use drill bushings to guide and position the oblique hole axis, but these are difficult to meet the batch machining needs of oblique holes with different angles.

[0004] In view of the above-mentioned shortcomings, the designer actively researched and innovated in order to create a drilling tool for machining oblique holes in mandrels, making it more valuable for industrial use. Utility Model Content

[0005] To solve the above-mentioned technical problems, the purpose of this utility model is to provide a drilling tool for machining oblique holes in a mandrel.

[0006] This utility model discloses a drilling fixture for machining inclined holes in a mandrel, comprising a machine tool worktable, wherein: a support adjustment block and a support block are respectively installed on the top surface of the machine tool worktable, and the top surfaces of the support adjustment block and the support block together form an integral inclined surface; a fixing plate is installed on the inclined surface; a chuck is installed on the top surface of the fixing plate, and the inner hole of the chuck is provided with three concentric positioning keys, which are used to fit and engage with the mandrel to achieve centering and clamping of the mandrel; a precision angle gauge is also installed on the top surface of the fixing plate to detect the included angle between the fixing plate and the top surface of the machine tool worktable; a drill bit is arranged above the chuck, and the axis of the drill bit is perpendicular to the top surface of the machine tool worktable.

[0007] Furthermore, in the aforementioned drilling fixture for machining oblique holes in a mandrel, the support adjustment block and the support block are distributed at intervals along the length of the top surface of the machine tool table; the top surface of the machine tool table is provided with several slots, and the bottom of the support adjustment block and the support block is provided with inserts; when the support adjustment block and the support block are combined with the machine tool table, the inserts are embedded in the corresponding slots.

[0008] Furthermore, in the aforementioned drilling fixture for machining oblique holes in a mandrel, the bottom surface of the fixed plate is completely fitted with the inclined surface formed by the support adjustment block and the support block, and the two are locked together by locking screws.

[0009] Furthermore, in the aforementioned drilling fixture for machining oblique holes of a mandrel, the axis of the chuck is perpendicular to the top surface of the fixed plate. After the mandrel is clamped in the inner hole of the chuck, the axis of the mandrel is collinear with the axis of the chuck and perpendicular to the top surface of the chuck. Threaded holes are provided at corresponding positions of the chuck and the fixed plate, and locking bolts are inserted into the threaded holes.

[0010] Furthermore, in the aforementioned drilling fixture for machining oblique holes in a mandrel, the three concentric locating keys are evenly distributed along the circumferential direction of the chuck's inner hole, and the three concentric locating keys ensure that the mandrel is subjected to uniform force when locking the mandrel.

[0011] Furthermore, in the aforementioned drilling fixture for machining oblique holes in a mandrel, the inner hole of the chuck is provided with several positioning grooves, and positioning blocks are distributed on the outer side of the concentric positioning key, with the positioning blocks embedded in the positioning grooves.

[0012] Furthermore, in the aforementioned drilling fixture for machining oblique holes in a mandrel, the outer wall of the chuck is provided with several positioning holes; the upper end of the concentric positioning key extends with a folding connecting piece, and the folding connecting piece is provided with a limiting hole; the folding connecting piece fits against the outer wall of the chuck, and positioning screws pass through the positioning holes and the corresponding limiting holes.

[0013] Furthermore, in the aforementioned drilling fixture for machining oblique holes in a mandrel, a connecting wing extends from the folding connecting piece; and gaskets are distributed on the inner side of the folding connecting piece.

[0014] Furthermore, in the aforementioned drilling fixture for machining oblique holes in a mandrel, the concentric positioning key is provided with contact blocks, the contact blocks are silicone blocks, and the outer surface of the silicone blocks is provided with several anti-slip grooves; the anti-slip grooves are rectangular grooves or mesh grooves.

[0015] Furthermore, in the aforementioned drilling fixture for machining oblique holes in a mandrel, the drill bit is clamped on the Z-axis spindle of the machine tool.

[0016] By means of the above solution, this utility model has at least the following advantages:

[0017] 1. The angle of the top inclined surface of the support adjustment block and the support block is strictly matched to the angle between the inclined hole to be machined on the mandrel and the axis of the mandrel. Combined with repeated calibration of the fixed plate angle by a precision angle gauge, it ensures that the axis of the inclined hole is precisely aligned with the axis of the drill bit. At the same time, three concentric positioning keys evenly distributed along the circumference of 120° in the chuck, together with the anti-slip design of the silicone contact block, can achieve uniform clamping and coaxial centering of the mandrel, avoiding machining deviations caused by mandrel deformation or offset under force, and fully meeting the stringent requirements of the electric spindle mandrel for the angle and position accuracy of the inclined hole.

[0018] 2. Compared to the inefficiencies of existing electrical discharge machining (EDM) and multi-axis machine tool processing, this invention offers high processing efficiency. Drilling can be completed simply by controlling the Z-axis up and down movement, eliminating the need to adjust the spindle angle or write complex machining programs. In batch processing, after the initial tooling calibration, there is no need for repeated angle adjustments; only a quick mandrel replacement and clamping via concentric positioning keys are required. The total machining time for a single mandrel can be reduced to 5-10 minutes, significantly improving batch production efficiency.

[0019] 3. No expensive four-axis / five-axis machine tools or EDM equipment are required; processing can be achieved with just a standard three-axis machine tool, reducing initial equipment investment costs by over 70%. The support adjustment block and support block are customized components with a simple structure and low manufacturing cost, eliminating the need for electrodes and other consumables required for EDM, further reducing consumable expenses. Furthermore, operation does not require specialized programming personnel; ordinary three-axis machine tool operators can complete the task after simple training, reducing labor costs and lowering the operational threshold.

[0020] 4. For mandrels with angled holes of different angles, there is no need to change the entire tooling; only the corresponding angle adjustment block and support block need to be replaced to achieve angle adaptation. The chuck is a three-jaw self-centering chuck, which can adapt to mandrels with a certain range of outer diameters. Therefore, there is no need to design a separate chuck for mandrels with different outer diameters. The overall structure is easy to replace and adjust, effectively avoiding the limitation that a single specification tooling can only process specific mandrels.

[0021] The above description is only an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it in accordance with the contents of the specification, the preferred embodiments of this utility model are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a drilling fixture used for machining oblique holes in a mandrel.

[0023] The meanings of the labels in the figures are as follows.

[0024] 1 Drill bit 2 Mandrel

[0025] 3. Chuck 4. Precision Angle Gauge

[0026] 5. Fixed plate; 6. Support and adjustment block

[0027] 7 Machine tool worktable 8 Support block

[0028] 9 Folding combination pieces Detailed Implementation

[0029] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit the scope of this utility model.

[0030] like Figure 1 A drilling fixture for machining oblique holes in a mandrel includes a machine tool table 7, which can be made of cast iron. Its top surface is milled to prevent angular displacement of upper components due to unevenness of the base. Simultaneously, the top surface of the machine tool table 7 has several rectangular slots, the width and depth of which are adapted to the inserts at the bottom of the support adjustment block 6 and the support block 8. After subsequent installation, the support adjustment block 6, the support block 8, and the machine tool table 7 do not exhibit significant lateral wobbling, preventing left-right displacement during assembly. The support adjustment block 6 and the support block 8 are customized components; their core function is to achieve angular compensation of the oblique hole in the mandrel 2 through the inclined surface of their top surfaces. Specifically, the angle between the oblique hole to be machined in the mandrel 2 and the axis of the mandrel 2 is denoted as angle A. Through milling, the top surfaces of the support adjustment block 6 and the support block 8 are integrated into an inclined surface. The angle between this inclined surface and the top surface of the machine tool table 7 is denoted as angle B, satisfying angle B = angle A. For example, if the angle A of the inclined hole of the mandrel 2 is 30°, then the angle B of the inclined surface is simultaneously set to 30°. This ensures that after the mandrel 2 is clamped, the axis of its inclined hole is exactly perpendicular to the top surface of the machine tool table 7, providing conditions for the drill bit 1 to drill vertically. During implementation, the support adjustment block 6 and the support block 8 are distributed at intervals of 100-150mm along the length of the top surface of the machine tool table 7. The rectangular inserts at their bottoms are embedded into the corresponding slots of the machine tool table 7 to achieve initial positioning. Subsequently, two hexagonal head screws (M8×20 screw specification) spaced apart along the height direction pass through the pre-set through holes of the support adjustment block 6 and the support block 8, and then engage with the threaded holes on the top surface of the machine tool table 7 to complete the fixing.

[0031] In the optimized implementation of this utility model, the top inclined surfaces of the support adjustment block 6 and the support block 8 are precision milled, and their inclined surfaces must be in the same plane (flatness error ≤ 0.01mm) to prevent tilting of the fixing plate 5 after assembly. The fixing plate 5 is made of medium carbon steel, which can transmit the inclined angle of the support adjustment block 6 and the support block 8 to the chuck 3 and provide a stable mounting base for the chuck 3. During installation, the bottom surface of the fixing plate 5 is completely in contact with the top inclined surfaces of the support adjustment block 6 and the support block 8, with no local suspension. Four internal hexagon socket head cap screws (screw specification M10×25) are used to penetrate the four corner through holes of the fixing plate 5, respectively, and engage with the threaded holes on the top surface of the support adjustment block 6 and the support block 8. After tightening, there is no relative looseness between the fixing plate 5 and the support adjustment block 6 and the support block 8, ensuring that the angle B is maintained synchronously with the inclined surface. At the same time, a precision angle gauge 4 is also installed on the fixing plate 5 to detect the included angle between the fixing plate 5 and the top surface of the machine tool worktable 7.

[0032] Furthermore, the chuck 3 used is a three-jaw self-centering chuck, which can adapt to the outer diameter of the mandrel 2. For example, if the outer diameter of the mandrel 2 is φ30mm, then the clamping range of the chuck 3 is φ10-φ50mm. Thus, precise centering and uniform clamping of the mandrel 2 are achieved through three concentric positioning keys. To achieve a stable connection, a circular flange can be provided at the bottom of the chuck 3. During implementation, four evenly distributed threaded holes are opened at corresponding positions on the top surface of the flange and the fixing plate 5. Four hexagon socket head cap screws are inserted through the through holes of the flange and engage with the threaded holes of the fixing plate 5. After tightening, the axis of the chuck 3 is perpendicular to the top surface of the fixing plate 5. Furthermore, the center of the chuck 3 is aligned with the center of the fixing plate 5.

[0033] In practical implementation, the inner wall of the chuck 3 has three rectangular positioning grooves evenly distributed along the circumference at 120°, each groove being 10mm wide and 5mm deep. A rectangular positioning block is correspondingly formed on the outer side of the concentric positioning key. A folding connecting piece 9 extends from the upper end of the concentric positioning key, integrally formed with the positioning key, with a thickness of 2-3mm and a folding angle of 90°. Simultaneously, a circular limiting hole is formed on the folding connecting piece 9, and a corresponding circular positioning hole is formed on the outer wall of the chuck 3. After placement, the folding connecting piece 9 is fitted against the outer wall of the chuck 3, aligning the limiting hole with the positioning hole, and the internal hexagon set screw is inserted and tightened to complete the fixation of the concentric positioning key. A silicone contact block is adhered to the side of the concentric positioning key facing the spindle 2 to prevent the metal positioning key from directly contacting the outer circumference of the spindle 2 and to prevent scratches. Furthermore, the outer surface of the silicone contact block is provided with anti-slip grooves—either rectangular grooves or mesh grooves can be selected—to increase the friction with the mandrel 2 and prevent the mandrel 2 from sliding axially or circumferentially during processing.

[0034] Considering both centering and clamping effects, after the mandrel 2 is inserted into the inner hole of the chuck 3, the three concentric positioning keys are driven to move synchronously towards the center until the silicone contact block is in close contact with the outer circumferential surface of the mandrel 2. At this time, the axis of the mandrel 2 is collinear with the axis of the chuck 3, and the mandrel 2 is subjected to uniform force, preventing deformation of the mandrel 2 due to excessive local force.

[0035] Furthermore, the precision angle gauge 4 used in this invention is a universal angle gauge. The fixed body of the precision angle gauge 4 can be attached to the top surface of the machine tool worktable 7. Then, the movable measuring jaw is attached to the outer wall of the fixed plate 5, and the angle of the movable jaw is slowly adjusted until it is completely attached to the outer wall of the fixed plate 5. Afterward, the angle value is read. This can be repeated three times, and the average value is taken. If the deviation of the average value from angle B exceeds 0.1°, the fixing screws of the support adjustment block 6, support block 8, or fixed plate 5 are loosened, fine-tuned, and then re-tested until the deviation is ≤0.1°, ensuring the angle accuracy of subsequent inclined hole machining.

[0036] During use, a high-speed steel twist drill (drill bit 1) is used. Drill bit 1 is clamped in the drill chuck of the machine tool's Z-axis spindle. The clamping range of the drill chuck is adapted to the diameter of drill bit 1; for example, if the diameter of drill bit 1 is φ5mm, then the clamping range of the drill chuck is φ1-φ10mm. Adjust the Z-axis spindle position so that the axis of drill bit 1 is perpendicular to the top surface of the machine tool's worktable 7 and collinear with the axis of the inclined hole to be machined on the end face of the mandrel 2. During drilling, only the Z-axis of the machine tool is controlled to move up and down in a direction perpendicular to the top surface of the machine tool's worktable 7. The machining of the inclined hole on the end face of the mandrel 2 can be completed without adjusting the spindle angle. This method is fully compatible with three-axis machine tools and eliminates the need for complex operations required for four-axis / five-axis machine tools.

[0037] The working principle of this utility model is as follows:

[0038] For tooling pre-assembly and angle calibration, based on the angle A of the inclined hole to be machined on the mandrel 2, select the corresponding angle B for the support adjustment block 6 and support block 8. Embed the inserts of both into the grooves of the machine tool worktable 7 and fix them with screws. Next, attach the fixing plate 5 to the inclined surfaces of the support adjustment block 6 and support block 8 and initially fix it with screws. Use a precision angle gauge 4 to check the angle, fine-tune it until the deviation is ≤0.1°, and then tighten the screws. Next, fix the chuck 3 to the top surface of the fixing plate 5 via the flange, ensuring that the axis of the chuck 3 is perpendicular to the fixing plate 5, and check the perpendicularity with a dial indicator. Then, embed the positioning blocks of the three concentric positioning keys into the positioning grooves of the chuck 3, and fix them with the folding coupling piece 9 and screws to complete the tooling pre-assembly.

[0039] Next, the mandrel 2 is clamped by placing it into the inner hole of the chuck 3. The three concentric positioning keys are then driven to simultaneously clamp the mandrel 2, ensuring that the axis of the mandrel 2 is collinear with the axis of the chuck 3, and that the silicone contact block is tightly fitted to the outer circumferential surface of the mandrel 2 without any looseness. The drill bit 1 is then clamped and aligned in the machine tool's Z-axis drill chuck. After detecting radial runout, the Z-axis position is adjusted to ensure that the axis of the drill bit 1 is collinear with the axis of the inclined hole of the mandrel 2.

[0040] Finally, start the machine tool and control the Z-axis to drive the drill bit 1 downward to drill to the preset depth. Then, the Z-axis returns to its original position to complete the oblique hole machining of a single mandrel 2. Release the concentric positioning key and remove the mandrel 2.

[0041] Furthermore, the directions or positional relationships described in this utility model are based on the directions or positional relationships shown in the accompanying drawings. They are only for the purpose of facilitating the description of this utility model and simplifying the description, and are not intended to indicate or imply that the device or structure referred to must have a specific orientation, or to operate in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0042] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A drilling fixture for machining oblique holes in a mandrel, comprising a machine tool table (7), characterized in that: The top surface of the machine tool worktable (7) is respectively equipped with a support adjustment block (6) and a support block (8), and the top surfaces of the support adjustment block (6) and the support block (8) together form an integral inclined surface; the fixed plate (5) is installed on the inclined surface; the top surface of the fixed plate (5) is equipped with a chuck (3), and the inner hole of the chuck (3) is provided with three concentric positioning keys. The three concentric positioning keys are used to fit and engage with the spindle (2) to achieve centering and clamping of the spindle (2); the top surface of the fixed plate (5) is also equipped with a precision angle ruler (4) to detect the included angle between the fixed plate (5) and the top surface of the machine tool worktable (7); above the chuck (3), a drill bit (1) is arranged, and the axis of the drill bit (1) is perpendicular to the top surface of the machine tool worktable (7).

2. The drilling fixture for machining oblique holes in a mandrel according to claim 1, characterized in that: The support adjustment block (6) and the support block (8) are distributed at intervals along the length of the top surface of the machine tool table (7); the top surface of the machine tool table (7) is provided with several slots, and the bottom of the support adjustment block (6) and the support block (8) is provided with inserts. When the support adjustment block (6) and the support block (8) are combined with the machine tool table (7), the inserts are embedded in the corresponding slots.

3. The drilling fixture for machining oblique holes in a mandrel according to claim 1, characterized in that: The bottom surface of the fixed plate (5) is completely fitted with the inclined surface formed by the support adjustment block (6) and the support block (8), and is locked together by the locking screw.

4. The drilling fixture for machining oblique holes in a mandrel according to claim 1, characterized in that: The axis of the chuck (3) is perpendicular to the top surface of the fixing plate (5). After the spindle (2) is clamped in the inner hole of the chuck (3), the axis of the spindle (2) is collinear with the axis of the chuck (3) and perpendicular to the top surface of the chuck (3). Threaded holes are provided at the corresponding positions of the chuck (3) and the fixing plate (5), and locking bolts are inserted in the threaded holes.

5. The drilling fixture for machining oblique holes in a mandrel according to claim 1, characterized in that: The three concentric positioning keys are evenly distributed along the circumference of the inner hole of the chuck (3), and the three concentric positioning keys make the mandrel (2) subjected to uniform force when locking the mandrel (2).

6. The drilling fixture for machining oblique holes in a mandrel according to claim 1, characterized in that: The chuck (3) has several positioning grooves inside its inner hole, and positioning blocks are distributed on the outer side of the concentric positioning key, with the positioning blocks embedded in the positioning grooves.

7. The drilling fixture for machining oblique holes in a mandrel according to claim 1, characterized in that: The outer wall of the chuck (3) is provided with a plurality of positioning holes; the upper end of the concentric positioning key extends with a folding connecting piece (9), and a limit hole is provided on the folding connecting piece (9); the folding connecting piece (9) fits against the outer wall of the outer wall of the chuck (3), and positioning screws are inserted in the positioning holes and the corresponding limit holes.

8. The drilling fixture for machining oblique holes in a mandrel according to claim 7, characterized in that: The folding connecting piece (9) has connecting wing pieces extending from it; gaskets are distributed on the inner side of the folding connecting piece (9).

9. The drilling fixture for machining oblique holes in a mandrel according to claim 1, characterized in that: The concentric positioning keys are distributed with contact blocks, which are silicone blocks. The outer surface of the silicone blocks is provided with several anti-slip grooves. The anti-slip grooves are rectangular grooves or mesh grooves.

10. The drilling fixture for machining oblique holes in a mandrel according to claim 1, characterized in that: The drill bit (1) is clamped on the Z-axis spindle of the machine tool.

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