Gravity compensation constant force adjustable aero-engine blade polishing and grinding device and method

Abstract

The invention relates to a constant-force grinding device and method based on gravity-elastic force dynamic balance, solves the problem of contact force fluctuation caused by blade profile deviation, actuating mechanism positioning error and grinding tool abrasion, and ensures that normal pressure is stabilized at a set threshold value in the polishing process. The device comprises a constant-force coil spring, a motor, a base, a limiting block, a linear guide rail, a balancing weight, a grinding wheel and a foundation frame. The linear guide rail in the vertical direction is installed on the foundation frame, the base is connected to the linear guide rail in a sliding mode and can move up and down on the linear guide rail, the motor is fixed to the base, the upper end of the constant-force coil spring is fixedly connected to the top of the foundation frame, and the lower end of the constant-force coil spring is connected with the base. The balancing weight is installed on the motor or the base, and the balancing weight requirement is calculated according to the target downward pressure F. The contact force stability is improved; the maintenance period is prolonged, and the constant-force floating structure does not need electrical maintenance.

Description

Technical Field

[0001] This invention relates to a gravity-compensated constant force adjustable aero-engine blade polishing and grinding device and method, belonging to the field of aero-engine blade maintenance technology. Background Technology

[0002] After long-term service, aero-engine blades will exhibit wear, deformation, and other defects, requiring polishing and grinding to restore their blade profile accuracy. Traditional blade grinding technology faces the following technical bottlenecks:

[0003] 1. Insufficient force control precision: The fixed grinding device disclosed in CN112847011A relies on the absolute positioning precision of the robotic arm to maintain contact force. However, differences in blade profile, robotic arm movement errors, and wear of the grinding wheel can cause fluctuations in contact pressure, which can easily lead to over-grinding (damage to the substrate) or under-grinding (insufficient polishing).

[0004] 2. Dynamic response hysteresis: For example, the pneumatic floating mechanism used in CN113245925B achieves force compensation by adjusting the cylinder pressure through a proportional valve. However, the compressibility of gas results in an excessively long system response time, which cannot adapt to the complex curvature of the blades.

[0005] 3. Poor environmental adaptability: The servo motor active force control solution described in CN114211325A is prone to force sensor misalignment in the high humidity (RH>80%) and dusty environment commonly found in engine repair workshops, requiring daily calibration.

[0006] To address the aforementioned shortcomings, there is an urgent need to develop a passive mechanical constant force compensation mechanism to achieve autonomous and stable control of the grinding contact force. Summary of the Invention

[0007] This invention provides a constant force polishing device and method based on gravity-elastic dynamic balance, which solves the problem of contact force fluctuation caused by blade profile deviation, actuator positioning error and polishing tool wear, and ensures that the normal pressure is stable at the set threshold (20N±5N) during the polishing process.

[0008] This invention is achieved through the following technical solution:

[0009] A gravity-compensated constant force adjustable aero-engine blade polishing and grinding device includes a constant force coil spring 1, a motor 2, a base 3, a limiting block 4, a linear guide rail 5, a counterweight 6, a grinding wheel 7, and a basic frame 8.

[0010] A vertical linear guide rail 5 is installed on the base frame 8. The base 3 is slidably connected to the linear guide rail 5 and can move up and down on the linear guide rail 5. The motor 2 is fixed on the base 3. The upper end of the constant force coil spring 1 is fixed to the top of the base frame 8 and the lower end is connected to the base 3. A limit block 4 is fixed on the linear guide rail 5 below the base 3. The motor 2 drives the grinding wheel 7 to rotate. The counterweight 6 is installed on the motor 2 or the base 3.

[0011] A method for polishing and grinding gravity-compensated constant-force adjustable aero-engine blades includes the following steps:

[0012] 1) Fix the base frame 8 to the workbench surface with bolts, ensuring that the overall levelness is ≤0.2°;

[0013] 2) Install the two constant force coil springs 1 to the top of the base frame 8 using bolts so that the coil springs can be pulled out smoothly;

[0014] 3) Install the two linear guide rails 5 to both sides of the base frame 8 with bolts, and adjust the parallelism to ±0.2mm;

[0015] 4) Install the base 3 onto the sliders of the two linear guide rails 5 using bolts;

[0016] 5) Install the grinding wheel 7 onto the motor shaft of motor 2, and then install motor 2 onto base 3;

[0017] 6) The moving end of the constant force coil spring 1 has two holes. The base 3 is connected to the two constant force coil springs 1 by bolts passing through the holes. The downward pressure F of the base 3, the grinding wheel 7, and the motor 2 under the tension of the coil spring within the operating range is tested by a force gauge.

[0018] 7) Calculate the counterweight requirement based on the target downforce F:

[0019]

[0020] Where m t Let F(d) be the weight of the counterweight, F(d) be the tension of the coil spring at a distance d, F be the target downward force, and m be the weight of the counterweight. b The required increase in downward pressure is calculated based on the total weight of the motor, base, and grinding wheel, and the downward pressure is adjusted by using counterweights.

[0021] 8) Install the two limit blocks 4 onto the fixed slide rail of the linear guide rail 5 by bolts, and adjust the installation position up and down so that the constant force coil spring 1 is pulled out within the range of use;

[0022] 9) Powering on the motor 2 causes it to rotate and drive the grinding wheel 7. The robotic arm clamps the blade and moves it from the lowest point of the grinding wheel 7 to the grinding wheel 7. After the blade contacts the grinding wheel 7, the robotic arm begins to move along the blade profile trajectory, always maintaining perpendicular normal contact with the grinding wheel 7. After completion, it leaves the grinding wheel 7, thus completing the work.

[0023] The beneficial effects of this invention are:

[0024] 1. Improved contact force stability: Pressure fluctuation < ±2.5% when there are abrupt changes in blade profile (curvature change of 0.5 to 2 mm⁻¹); (compared to ±15% for traditional fixed solutions)

[0025] 2. Environmental robustness: Under the conditions of temperature -20℃~80℃ and vibration acceleration of 3g (GB / T 2423.10), the force output drift is <1%;

[0026] 3. Extended maintenance cycle: The constant force floating structure requires no electrical maintenance, and the lifespan of key components (coil springs, guide rails) is >107 cycles.

[0027] This invention can be extended to polishing and grinding other types of parts. By replacing the traditional fixed grinding device with this constant force device, floating constant force grinding can be achieved. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the device structure of the present invention. Detailed Implementation

[0029] Figure 1 The image shows a gravity-compensated constant-force adjustable aero-engine blade polishing and grinding device according to the present invention, comprising a constant-force coil spring 1, a motor 2, a base 3, a limiting block 4, a linear guide rail 5, a counterweight 6, a grinding wheel 7, and a basic frame 8. The functions of each component are as follows:

[0030] Constant force coil spring: provides a constant upward pulling force relative to gravity within a certain distance range.

[0031] Motor: Drives the grinding wheel to rotate at a speed of 2000 rpm and provides downward pressure.

[0032] Base: Mounts and fixes the motor, connects to the linear guide rail, connects to the coil spring, and can move up and down on the guide rail.

[0033] Limiting block: limits the downward distance of the coil spring, ensuring that the coil spring operates within its operating range.

[0034] Linear guide rails: provide smooth up-and-down movement of the base on the foundation frame.

[0035] Counterweight: The downward pressure is controlled by the weight of the counterweight, and the weight of the counterweight is directly proportional to the downward pressure.

[0036] Grinding wheel: Driven by the rotation of the motor, it comes into contact with the blade and grinds and polishes the blade surface.

[0037] Basic frame: Provides the mounting location for the entire unit and secures it to different devices with screws, providing a stable working foundation.

[0038] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the following description.

[0039] A gravity-compensated adjustable blade constant force polishing and grinding device for aero-engines mainly comprises: 1. constant force coil spring; 2. motor; 3. base; 4. limit block; 5. linear guide rail; 6. counterweight; 7. grinding wheel; 8. basic frame and other parts.

[0040] When it works, it includes the following steps:

[0041] 1. Fix the base frame 8 to the workbench with bolts, ensuring that the overall levelness is ≤0.2°.

[0042] 2. By using bolts, install two constant force coil springs 1 to the top position of the base frame 8 so that the coil springs can be pulled out smoothly.

[0043] 3. Install the two linear guide rails 5 to both sides of the base frame 8 with bolts, and adjust the parallelism to ±0.2mm.

[0044] 4. Mount the base 3 onto the sliders of the two linear guide rails 5 using bolts.

[0045] 5. Install the grinding wheel 7 onto the motor shaft of motor 2, and then install the motor onto the base 3.

[0046] 6. The moving end of the constant force coil spring 1 has two holes. The base 3 is connected to the two constant force coil springs 1 by bolts passing through the holes. The downward pressure F1 of the base 3, the grinding wheel 7, and the motor 2 under the tension of the coil springs within the operating range is tested by a force gauge.

[0047] 7. Calculate the counterweight requirement based on the target downforce F:

[0048]

[0049] Where m t Let F(d) be the weight of the counterweight, F(d) be the tension of the coil spring at a distance d, F be the target downward force, and m be the weight of the counterweight. b The required increase in downward pressure is calculated based on the total weight of the motor, base, and grinding wheel, and the downward pressure is adjusted by using counterweights.

[0050] 8. Install the two limit blocks 4 onto the fixed slide rail of the linear guide rail 5 using bolts, and adjust the installation position up and down so that the constant force coil spring 1 is pulled out within the range of use.

[0051] 9. Powering on the motor 2 causes it to rotate and drive the grinding wheel 7. The robotic arm clamps the blade and moves it from the lowest point of the grinding wheel 7 to the grinding wheel 7. After the blade contacts the grinding wheel 7, the robotic arm begins to move along the blade's profile trajectory, always maintaining a perpendicular normal contact with the grinding wheel 7. Once completed, the robotic arm leaves the grinding wheel 7, thus completing the work.

[0052] The above description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or related technologies or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A gravity-compensated constant-force adjustable aero-engine blade polishing and grinding device, characterized in that: It includes a constant force coil spring (1), a motor (2), a base (3), a limit block (4), a linear guide rail (5), a counterweight (6), a grinding wheel (7), and a basic frame (8); A vertical linear guide (5) is installed on the base frame (8), and the base (3) is slidably connected to the linear guide (5). The motor (2) is fixed on the base (3). The upper end of the constant force coil spring (1) is fixed to the top of the base frame (8), and the lower end is connected to the base (3). A limit block (4) is fixed on the linear guide (5) below the base (3). The motor (2) drives the grinding wheel (7) to rotate. The counterweight (6) is installed on the motor (2) or the base (3).

2. A method for polishing and grinding aero-engine blades with adjustable constant force and gravity compensation, characterized in that: Includes the following steps: 1) Fix the base frame (8) to the workbench; 2) Install two constant force coil springs (1) to the top of the base frame (8) using bolts so that the coil springs can be pulled out smoothly; 3) Install the two linear guides (5) onto both sides of the base frame (8); 4) Install the base (3) onto the sliders of the two linear guides (5); 5) Install the grinding wheel (7) onto the motor shaft of the motor (2), and then install the motor (2) onto the base (3); 6) The moving end of the constant force coil spring (1) has two holes. The base (3) is connected to the two constant force coil springs (1) by bolts passing through the holes. The pressure F of the base (3), grinding wheel (7), and motor (2) under the tension of the coil spring within the operating range is tested by a force gauge. 7) Calculate the counterweight requirement based on the target downforce F: Where m t Let F(d) be the weight of the counterweight, F(d) be the tension of the coil spring at a distance d, F be the target downward force, and m be the distance between the counterweight and the target downward force. b The required increase in downward pressure is calculated based on the total weight of the motor, base, and grinding wheel, and the downward pressure is adjusted by using counterweights. 8) Install two limit blocks (4) onto the fixed slide rail of the linear guide (5) and adjust the installation position up and down so that the constant force coil spring (1) is pulled out within the range of use; 9) Powering on the motor (2) causes it to rotate and drive the grinding wheel (7). The mechanical arm clamps the blade and moves it from the lowest point of the grinding wheel (7) to the grinding wheel (7). After the blade contacts the grinding wheel (7), the mechanical arm begins to move along the blade profile trajectory, always maintaining a perpendicular normal contact with the grinding wheel (7). After completion, it leaves the grinding wheel (7) and completes the work.

3. The method for polishing and grinding gravity-compensated constant-force adjustable aero-engine blades according to claim 2, characterized in that: After fixing the base frame (8) to the workbench, the overall levelness is ≤0.2°.

4. The method for polishing and grinding aero-engine blades with adjustable constant force and gravity compensation according to claim 2, characterized in that: After the two linear guide rails (5) are installed on both sides of the base frame (8), the parallelism is adjusted to not exceed ±0.2mm.

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