Machining tool and machining method for wear-resistant bushing of aero-engine

Abstract

The aero-engine wear-resistant bushing machining tool is characterized in that the aero-engine wear-resistant bushing machining tool comprises a core shaft, a guide wheel and a correction wheel, the rotating axes of the core shaft, the guide wheel and the correction wheel are parallel to one another, and working gaps are reserved between the core shaft and the guide wheel and between the core shaft and the correction wheel respectively; the thickness of the working gap corresponds to the thickness of a plate to be machined, the mandrel is driven by a driving device to rotate, the abrasion-resistant oil control sleeve to be machined is driven by rotation of the mandrel to rotate around the mandrel, and the guide wheel and the correction wheel are driven by friction force of the abrasion-resistant oil control sleeve to rotate along with the mandrel. Friction resistance is reduced by loading the deep groove ball bearing, uniform stress is achieved, stress concentration is reduced, and local excessive extrusion deformation is avoided. Beryllium bronze with high abrasion resistance is used for manufacturing the knurled guide wheel to increase rolling friction force, the knurled guide wheel rotates at a constant speed through the bearing to achieve uniform stress without clamping stagnation, starting resistance is reduced, and surface defects are avoided.

Description

Technical Field

[0001] This invention relates to the field of roll forming, and more particularly to a tooling and method for machining wear-resistant bushings for aero-engines. Background Technology

[0002] With the continuous development of fuel systems for aero engines and gas turbines, a key product in these systems—the wear-resistant fuel control sleeve—is crucial. Its function is to fully utilize the critical flow channels in fuel and gas nozzles, preventing fuel backflow and leakage onto the engine surface during assembly and operation, thus avoiding safety hazards caused by assembly stress and friction. To meet design requirements during processing, existing processing methods have certain shortcomings in terms of efficiency and quality. The following processing technical challenges exist, and their current production status and processing difficulties are as follows: After manual bending, the ellipticity reaches 3-4mm, and the wall thickness is only 1.2mm. The straightening process is prone to causing indentations. The hardened surface layer and residual stress after bending cause secondary deformation after 3-4 days. Multiple straightening processes are required for the same specifications (Φ19.5–Φ20.5), and the smaller the diameter, the more severe the deformation. The GH4169 material used is 3 times harder than ordinary 45 steel, which increases the processing difficulty. Summary of the Invention

[0003] The purpose of this invention is to provide a machining fixture and method for wear-resistant bushings in aero-engines, in order to solve a series of technical bottlenecks in one-time machining, such as irregular outer diameter and cylindricity deformation coefficients after manual bending of wear-resistant oil control bushings, which can even lead to misalignment, difficulty in shape correction, and residual stress release.

[0004] This invention is achieved using the following technical solution: a tooling for processing wear-resistant bushings for aero-engines, characterized in that it includes a mandrel, a guide wheel, and a straightening wheel. The rotation axes of the mandrel, guide wheel, and straightening wheel are parallel to each other. A working gap is left between the mandrel and each of the guide wheel and straightening wheel. The thickness of the working gap corresponds to the thickness of the sheet metal to be processed. The mandrel is driven to rotate by a drive device, and the rotation of the mandrel causes the wear-resistant oil control bushing to be processed to rotate around the mandrel. The guide wheel and straightening wheel rotate with the mandrel under the frictional force of the wear-resistant oil control bushing. Through the parallel layout of the three axes and the gap constraint, continuous roll forming of the sheet metal is achieved, eliminating the risk of misalignment from manual bending and ensuring a cylindricity ≤0.05mm.

[0005] Furthermore, the mandrel is driven by the machine tool spindle, and the mandrel is connected to the machine tool spindle via a chuck. This directly utilizes the machine tool's power source, providing a stable rotational speed and avoiding uneven speed caused by manual operation, thus reducing stress concentration at its source.

[0006] Furthermore, the guide wheel and the correction wheel are rotatably connected to the actuating handle, which is mounted on the machine tool post. The tool post rigidly supports the actuating handle to prevent axial movement.

[0007] Furthermore, the guide wheel and the correction wheel are respectively connected to the actuating handle via pins, and the two ends of the pins are rotatably connected to the actuating handle via bearings. This avoids jamming under heavy loads and evenly distributes the compressive force, preventing localized indentation.

[0008] Furthermore, the bearing is a deep groove ball bearing. Deep groove ball bearings simultaneously bear radial and axial loads, maintain smooth operation under pre-bending heavy load conditions, and suppress aging deformation caused by stress concentration.

[0009] Furthermore, the guide wheel's rolling surface is provided with knurling, which is made of beryllium bronze. The beryllium bronze knurling provides high wear resistance and friction enhancement, ensuring that the sheet metal feed is non-slip and does not damage the GH4169 alloy surface.

[0010] A method for machining wear-resistant bushings for aero-engines includes the following steps: Step 1: Install the actuating handle vertically to the spindle, ensuring that the spindle is parallel to the guide wheel, so that the wear-resistant oil control sleeve does not break during bending. Step 2: Adjust the width between the guide wheel and the mandrel to match the thickness of the sheet metal to be processed. By hand, place the sheet metal to be processed in the gap between the guide wheel and the mandrel. Start the lathe spindle to drive the mandrel to rotate clockwise, so that the wear-resistant oil control sleeve sheet metal rotates clockwise by the mandrel, while driving the guide wheel to rotate counterclockwise. Step 3: After the wear-resistant oil control sleeve material enters the gap between the correction wheel and the mandrel, rotate it one revolution to complete the pre-bending. At this time, the wear-resistant oil control sleeve material forms an irregular cylinder. Step four: After pre-bending, the mandrel enters the secondary bending and forming stage. At this time, the mandrel rotates counterclockwise, mainly under the micro-squeezing constraint of the guide wheel, and then rotates once again through the rolling friction of the correction wheel.

[0011] The beneficial effects of the wear-resistant bushing machining tooling and machining method for aero-engines described in this invention include: By using deep groove ball bearings to reduce frictional resistance, uniform force distribution and stress concentration are achieved, avoiding localized excessive extrusion deformation, thus improving load-bearing capacity and enabling the bearing to withstand radial loads while reducing axial loads. It does not jam under pre-bending heavy loads and will not cause localized excessive extrusion, resulting in stress concentration and post-processing aging deformation.

[0012] Because the surface of high-temperature alloy 4169 will produce a hardened layer and a neutral layer after bending, the residual stress is strong and it is very easy to deform. By using a gap of less than 0.06mm product thickness for constraint pre-bending, and then correcting after bending, one-time forming is achieved.

[0013] Using beryllium bronze with high wear resistance to make knurled guide wheels increases rolling friction. The knurled guide wheels rotate at a constant speed through bearings to achieve uniform force distribution and no jamming, reducing starting resistance and avoiding surface defects. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0015] Figure 1 A schematic diagram of a tooling for machining wear-resistant bushings for aero-engines; Figure 2 A side view of a tooling for machining wear-resistant bushings for aero-engines; Figure 3 A schematic diagram showing the machining process of a wear-resistant oil control sleeve; In the diagram, 1-bearing; 2-actuator; 3-guide wheel; 4-correction wheel; 5-pin; 6-wear-resistant oil control sleeve; 7-spindle; 8-chuck; 9-bolt; 10-tool holder. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0017] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention. Example

[0018] like Figure 1-3As shown, this embodiment provides a machining fixture for wear-resistant bushings in aero-engines, including one active rolling shaft and two driven rolling shafts. The active rolling shaft is a mandrel 7, and the driven rolling shafts are guide wheels 3 and straightening wheels 4. The wear-resistant oil control bushing 6 is formed by two rolling processes via the mandrel 7, guide wheels 3, and straightening wheels 4. The wear-resistant oil control bushing 6 to be machined is made of a sheet metal with dimensions of 18mm x 62.8mm and a thickness of 1.2mm. The material used has a Brinell hardness of 360 degrees, which is three times the standard hardness of ordinary 45 steel.

[0019] The mandrel 7 is fixed to the machine tool spindle by a chuck 8. The machine tool drives the mandrel 7 to rotate, and its axis of rotation forms the reference axis of the tooling. The guide wheel 3 and the correction wheel 4 are mounted on the actuating handle 2 by a pin 5. The actuating handle 2 is fastened to the tool post 10 by bolts 9. The installation and adjustment of the tooling are achieved by adjusting the relative position of the actuating handle 2 and the mandrel 7.

[0020] Specifically, two pins 5 pass through the guide wheel 3 and the correction wheel 4 respectively. The two ends of the pins 5 are connected to the actuating handle 2 through bearings 1 respectively, so that the guide wheel 3 and the correction wheel 4 can rotate freely around the axis of the pins 5 on the actuating handle 2.

[0021] The rotation axis of the mandrel 7 is parallel to the rotation axis of the guide wheel 3 and the correction wheel 4. There is a gap between the mandrel 7 and the guide wheel 3 and the correction wheel 4. The gap width is 0.06mm smaller than the thickness of the wear-resistant oil control sleeve 6. This dimension is used to provide micro-constraint, thereby reducing the problems of unstable product clamping and irregular deformation, or the disadvantages of product clamping deformation caused by axial movement during clamping.

[0022] The guide wheel 3 has knurling on its rolling surface. The knurling is made of beryllium bronze with high wear resistance. The knurling increases the starting friction and micro-extrusion.

[0023] The bearing 1 uses a deep groove ball bearing to reduce frictional resistance, achieve uniform force distribution, and reduce stress concentration, thus avoiding localized excessive compression deformation. It does not jam under pre-bending heavy loads and will not cause localized excessive compression, resulting in stress concentration and post-processing aging deformation. Example

[0024] This embodiment is a method for machining wear-resistant oil control sleeves based on the machining tooling of Embodiment 1, specifically including the following steps: Step 1: Install the actuator 2 vertically to the spindle 7, ensuring that the spindle 7 is parallel to the guide wheel 3, so that the wear-resistant oil control sleeve 6 does not break during bending.

[0025] Step 2: Adjust the width between guide wheel 3 and spindle 7 to 1.15mm. By hand, place the 18X62.8 mm rectangular plate between guide wheel 3 and spindle 7. Start the lathe spindle to drive spindle 7 to rotate clockwise, creating a starting motion pair. This causes the wear-resistant oil control sleeve 6 plate to rotate clockwise by the spindle 7, while simultaneously driving guide wheel 3 to rotate counterclockwise.

[0026] Step 3: After the wear-resistant oil control sleeve 6 plate enters the gap between the correction wheel 4 and the mandrel 7, it rotates once to complete the pre-bending. At this time, the wear-resistant oil control sleeve 6 plate forms an irregular cylinder, and the opening of the wear-resistant oil control sleeve 6 is 2.5 mm.

[0027] Step four: After the first pre-bending, the second bending and forming process begins. At this point, the mandrel 7 rotates counterclockwise, primarily under the micro-compression constraint of the guide wheel 3, and then rotates again once through rolling friction of the correction wheel 4. This reduces axial frictional resistance, ensuring uniform force distribution and minimizing stress concentration, thus preventing localized excessive compression deformation. This achieves the second-constraint bending and forming process, at which point the opening size of the wear-resistant oil control sleeve 6 is less than 1 mm.

[0028] The above embodiments describe the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Modifications and variations made by those skilled in the art without departing from the spirit and scope of the invention should be within the protection scope of the appended claims.

Claims

1. A tooling for machining wear-resistant bushings for aero-engines, characterized in that, The assembly includes a mandrel (7), a guide wheel (3), and a correction wheel (4). The rotation axes of the mandrel (7), the guide wheel (3), and the correction wheel (4) are parallel to each other. The mandrel (7) has a working gap between itself and the guide wheel (3) and the correction wheel (4). The thickness of the working gap corresponds to the thickness of the plate to be processed. The mandrel (7) is driven to rotate by a drive device, and the rotation of the mandrel (7) drives the wear-resistant oil control sleeve (6) to be processed to rotate around the mandrel (7). The guide wheel (3) and the correction wheel (4) rotate with the mandrel (7) under the friction of the wear-resistant oil control sleeve (6).

2. The tooling for machining wear-resistant bushings for aero-engines according to claim 1, characterized in that, The spindle (7) is driven by the machine tool spindle and is connected to the machine tool spindle via a chuck (8).

3. The tooling for machining wear-resistant bushings for aero-engines according to claim 1, characterized in that, The guide wheel (3) and the correction wheel (4) are rotatably connected to the actuating handle (2), which is mounted on the machine tool post.

4. The tooling for machining wear-resistant bushings for aero-engines according to claim 3, characterized in that, The guide wheel (3) and the correction wheel (4) are respectively connected to the actuating handle (2) via pins (5), and the two ends of the pins (5) are rotatably connected to the actuating handle (2) via bearings (1).

5. The machining fixture for wear-resistant bushings of aero-engines according to claim 4, characterized in that, The bearing (1) is a deep groove ball bearing.

6. The tooling for machining wear-resistant bushings for aero-engines according to claim 1, characterized in that, The guide wheel (3) has knurling on its rolling surface, and the knurling is made of beryllium bronze.

7. A method for machining wear-resistant bushings for aero-engines, implemented using the machining fixture described in any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Install the actuating handle (2) perpendicular to the spindle (7) to ensure that the spindle (7) is parallel to the guide wheel (3) so that the wear-resistant oil control sleeve (6) does not break during bending. Step 2: Adjust the width between the guide wheel (3) and the spindle (7) to match the thickness of the sheet metal to be processed. Place the sheet metal to be processed in the gap between the guide wheel (3) and the spindle (7) by hand. Start the lathe spindle to drive the spindle (7) to rotate clockwise, so that the wear-resistant oil control sleeve (6) sheet metal rotates clockwise by the spindle (7), while driving the guide wheel (3) to rotate counterclockwise. Step 3: After the wear-resistant oil control sleeve (6) plate enters the gap between the correction wheel (4) and the mandrel (7), it rotates once to complete the pre-bending. At this time, the wear-resistant oil control sleeve (6) plate forms an irregular cylinder. Step 4: After pre-bending, the second bending process begins. At this time, the mandrel (7) rotates counterclockwise. It rotates once again through rolling friction under the micro-squeezing constraint of the guide wheel (3) and the correction wheel (4).

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