Method for removing material from the balancing weight ring and correcting the high-speed dynamic balance of a slender shaft

Abstract

The present invention discloses a method for removing material from a balancing weight ring for high-speed dynamic balancing of a slender shaft and a method for correcting high-speed dynamic balancing. The method for removing material from the balancing weight ring is to arrange a balancing weight block at an angular position corresponding to a deflection value corresponding to a critical speed of the slender shaft. The length L of the balancing weight ring removed is: wherein m is the mass of the balancing weight block, R 块 R is the axial radius of the counterweight block. 环 is the mass radius of the balancing weight ring, k is the coefficient of the relationship between the length of the balancing weight ring and the mass of the balancing weight ring, k = 0.295; the torque of the balancing weight block is decomposed to the 45° direction of the center of the balancing weight ring claw, and the corresponding claws in the opposite direction of the balancing weight ring are removed, and the corresponding claw removal length L n For: L n = L × B × t, where B is the angle between the angular direction of the counterweight and the center of the balancing weight ring jaws at a 45° angle, t is the stock removal coefficient (t = 1.4), and n is the number of the jaws. The stock removal design of the present invention essentially ensures that the high-speed dynamic balancing deflection value of the slender shaft is within the acceptable range even with a single stock removal, resulting in a high success rate for one-time correction.

Description

Technical Field

[0001] The present invention relates to the technical field of high-speed dynamic balancing of shaft parts, and in particular to a method for removing material from a balancing weight ring for high-speed dynamic balancing of a slender shaft and a method for correcting the high-speed dynamic balancing. Background Art

[0002] Slender shafts are typically thin-walled and hollow, resulting in poor rigidity and significant machining challenges. Deformation, wall thickness, and runout tolerances have long been a major machining challenge, and inspection is also challenging. For example, the turbine shaft of an aircraft engine is a typical slender shaft. These machining issues, under high engine speeds, can cause shaft deflection, rotor instability, and other abnormalities, leading to engine vibration, abrasion, and other failures, seriously impacting the engine's operational safety.

[0003] To prevent slender shaft machining issues from directly impacting the proper operation of aircraft engines, high-speed dynamic balancing tests are performed on slender shafts. These tests simulate the shaft's operating conditions at full speed to verify whether the shaft's rotor characteristics meet the engine's operational requirements. If high-speed dynamic balancing fails, corrections can be made by removing material from the slender shaft or its internal connecting parts, improving engine reliability and reducing assembly, testing, and maintenance costs.

[0004] A certain type of turboprop engine power turbine shaft assembly as shown in the instruction manual Figure 1 As shown, it consists of a power turbine shaft, a balancing weight ring and blind rivets. The shaft length is 1409mm. The high-speed dynamic balancing of the power turbine shaft is achieved by removing material from the balancing weight ring. The balancing weight ring is installed inside the power turbine shaft. One of the rivet holes of the balancing weight ring is at position 0 (the symmetrical rivet holes are at 180 degrees), which is aligned with the 0 position of the power turbine shaft. The rivet holes of the balancing weight ring are fixed by blind rivets, as shown in the figure. Figure 2 As shown, the balance weight ring is inside the power turbine shaft. Figure 3 The four-claw structure shown cannot directly remove the marked angles and gram weight to ensure that the deflection value meets the requirements.

[0005] The patent with publication number CN116183105A discloses a balancing weight ring for dynamic balancing of thin-walled slender shaft parts. The thin-walled slender shaft parts are provided with an assembly hole for assembling the balancing weight ring. The balancing weight ring is cylindrical. The first end of the balancing weight ring is symmetrically provided with a through hole corresponding to the assembly hole of the part, and the end surface of the second end is evenly provided with an even number of grooves, and the grooves extend along the length direction of the balancing weight ring. The fan-shaped structure formed between adjacent grooves is the material removal part according to the unbalance amount of the part; the balancing weight ring is evenly distributed to four quadrants, and the weight angle α and the weight quadrant are determined according to the angle between the dynamic balancing focus of the part and the assembly hole. The quadrant symmetrically distributed with the weight quadrant is the material removal quadrant; when the weight quadrant is located in a single quadrant, the material removal amount of the material removal quadrant When the counterweight quadrants are located in two adjacent quadrants, the removal amounts of the two removal quadrants are:

[0006]

[0007] According to the relevant records in the above-mentioned patent, the patent is aimed at low-speed dynamic balancing of slender shafts. Generally speaking, low-speed dynamic balancing is aimed at rigid rotors, while high-speed dynamic balancing is aimed at flexible rotors. Some slender shafts are balanced at both low and high speeds. Since the distribution of imbalance causes complex bending deformation to flexible rotors, dynamic balancing must be performed separately in multiple planes and multiple speeds. Therefore, sometimes a rotor that is balanced well at low speed and the first critical speed still fails to meet the requirements when vibrating at the operating speed. Therefore, high-speed dynamic balancing is required for such slender shafts to ensure high reliability of their subsequent work. The low-speed dynamic balancing design in the above-mentioned patent is not suitable for high-speed dynamic balancing operations. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide a method for removing material from a balancing weight ring for high-speed dynamic balancing of a slender shaft in response to the defects of the existing technology, which can achieve the minimum number of material removals and quickly achieve the high-speed dynamic balancing correction effect of the slender shaft.

[0009] The purpose of the present invention is achieved through the following technical solutions:

[0010] A method for removing material from a balancing weight ring for high-speed dynamic balancing of a slender shaft is provided. A balancing weight block is provided at an angular position corresponding to the deflection value corresponding to the critical speed of the slender shaft. The removed length L of the balancing weight ring is: Where m is the mass of the counterweight, R 块 R is the axial radius of the counterweight block. 环 is the mass radius of the balancing weight ring, k is the coefficient of the relationship between the length of the balancing weight ring removed and the mass of the removed material, k = 0.295;

[0011] Then decompose the torque of the counterweight block to the 45° direction of the center of the balance weight ring claw, and remove the corresponding claw in the opposite direction of the balance weight ring. The corresponding claw removal length L n For: L n =L×B×t, where B is the trigonometric function relationship between the angular direction of the counterweight block and the 45° direction of the center of the balance weight ring claw, t is the material removal coefficient, t=1.4, and n is the claw number.

[0012] Furthermore, the removal tolerance of the corresponding claws on the balancing weight ring is ±0.1mm.

[0013] Furthermore, the counterweight is a lead block.

[0014] Furthermore, the counterweight block is a thin arc-shaped block.

[0015] Furthermore, R 块 The value is the radius of the slender axis.

[0016] Furthermore, the counterweight is fixed to the elongated shaft by a binding strap or an adhesive tape.

[0017] Furthermore, the detection of the deflection value of the slender shaft is achieved by arranging a plurality of displacement sensors on the slender shaft for measuring the vibration displacement of the slender shaft in the axial direction and the radial direction.

[0018] Furthermore, there are four displacement sensors, two of which are arranged on the outer periphery of the slender shaft corresponding to the positions where the four claws of the balancing weight ring begin to extend, and are used to measure the vibration displacement in the axial direction and radial direction of the slender shaft respectively. The remaining two displacement sensors are used to measure the vibration displacement in the axial direction of the slender shaft, and are distributed on both sides of the balancing weight ring along the axial direction of the slender shaft.

[0019] The present invention also provides a method for performing high-speed dynamic balance correction of a slender shaft using the above-mentioned balancing weight ring removal method, comprising the following steps:

[0020] S1. Before performing a high-speed dynamic balancing test on a slender shaft, mark the 0, 90, 180, and 270-degree positions, using a rivet hole on the balancing weight ring as the zero position.

[0021] S2. Perform a high-speed dynamic balancing test on the slender shaft, focusing on the deflection. When the deflection exceeds 250 μm, observe the deflection and angular position corresponding to the critical speed. After stopping the test, add counterweights to the outer periphery of the slender shaft.

[0022] S3. Start the high-speed dynamic balancing test to confirm whether the deflection value is within 250μm after the counterweight is installed. If it is satisfied, stop the test; if not, continue to add counterweights until it is satisfied.

[0023] S4. Weigh the added counterweight, confirm the counterweight position, and calculate the length L of the corresponding claws of the balance weight ring. n ;

[0024] S5. Remove the balancing weight ring. Ensure that the angular direction of the balancing weight ring remains unchanged during the removal process and determine the claw number.

[0025] S6. Remove material L on the corresponding jaws n ;

[0026] S7. Reinstall the balancing weight ring;

[0027] S8. Conduct high-speed dynamic balancing test again to verify whether the deflection value after material removal meets the design requirements.

[0028] Furthermore, if the deflection value verified in S8 still does not meet the design requirements, S2 to S8 need to be repeated.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The present invention specially designs the amount of material removed on the claws related to the balancing weight ring, which can basically ensure that the high-speed dynamic balance deflection value of the slender shaft is within the qualified range after one material removal. The one-time correction success rate is high, and the labor cost, parts loss cost and testing cost of repeated disassembly and assembly can be effectively reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a cross-sectional view of the power turbine shaft (including the balancing weight ring) described in Example 1 of the present invention;

[0032] Figure 2 for Figure 1 Enlarged view at point I in the middle;

[0033] Figure 3 This is a schematic structural diagram of the balancing weight ring according to Example 1 of the present invention;

[0034] Figure 4 This is a schematic diagram of the arrangement of the counterweight according to Example 1 of the present invention;

[0035] Figure 5 This is a schematic diagram of the torque decomposition of the counterweight block according to Example 1 of the present invention;

[0036] Figure 6 for Figure 5 Schematic diagram of the corresponding balance weight ring claws that need to be removed (front sectional view);

[0037] Figure 7 for Figure 6 Middle BB cross-section;

[0038] Figure 8 This is a schematic diagram of the measured deflection value described in Example 2 of the present invention. DETAILED DESCRIPTION

[0039] In order to clearly illustrate the technical features of this solution, the technical solution is described in detail below through specific implementation methods and in conjunction with the accompanying drawings.

[0040] In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present application is not limited to the specific embodiments disclosed below.

[0041] In addition, in the description of the present application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0042] In this application, unless otherwise expressly specified or limited, terms such as "installed," "connected," "connect," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0043] In this application, unless otherwise expressly specified and limited, a first feature "above" or "below" a second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in an appropriate manner in any one or more embodiments or examples.

[0044] Example 1

[0045] like Figure 1 and Figure 2 The power turbine shaft 1 shown in FIG. Figure 3The balancing weight ring 2 shown in the figure has a four-claw structure. This embodiment provides a method for removing the balancing weight ring for high-speed dynamic balancing of the power turbine shaft. When the deflection value obtained from the high-speed balancing test is greater than 250um, the balancing weight ring 2 needs to be removed. Figure 4 As shown, a counterweight 3 is provided at the angular position corresponding to the deflection value corresponding to the critical speed of the power turbine shaft. The counterweight 3 is preferably a lead block, and a thin arc-shaped lead block can meet the requirements. The counterweight 3 is fixed to the power turbine shaft 1 by wrapping a strap or tape around the circumference of the power turbine shaft. The blanking length L of the balancing weight ring 2 is designed as follows:

[0046] Balance weight ring removal mass M×mass radius R 环 = mass of counterweight m × axial radius R at counterweight 块 ;

[0047] In this embodiment, a corresponding relationship is specially designed between the length L of the balance weight ring 2 and the weight of the balance weight ring 2: L = M / k;

[0048] From the above, we can get: the length of the balance weight ring 2 Where m is the mass of the counterweight 3, R 块 is the axial radius of the counterweight 3, R 环 is the mass radius of the balancing weight ring 2, k is the relationship coefficient between the removed length of the balancing weight ring 2 and the removed mass, k = 0.295.

[0049] In this embodiment, R 环 The value is 11.3mm, so there is a balance weight ring 2 removal length

[0050] Then the moment of the counterweight 3 is decomposed to the 45° direction of the center of the claw of the balance weight ring 2, and the corresponding claw 21 in the opposite direction of the balance weight ring 2 is removed to achieve balance. The length of the corresponding claw 21 removed is L. n For: L n =L×B×t, where B is the trigonometric function relationship between the angular direction of the counterweight block 3 and the 45° direction of the center of the claw of the balance counterweight ring 2, t is the material removal coefficient, t=1.4, and n is the serial number of the claw 21.

[0051] For example, Figures 5-7 As shown, the balance weight ring 2 has the first to fourth claws 21 in the clockwise direction, and the weight block 3 is on the left of the first claw 21. Figure 5 and Figure 7 The middle No. 3 clamping jaw 21 and the No. 2 clamping jaw 21 go up to remove the material.

[0052] Length of material removed from No.3 jaw 21

[0053] Length of material removed from No.2 jaw 21

[0054] Among them, A is the angle between the setting position of the counterweight block 3 and the 0 position (taking a rivet hole on the balance weight ring 2 as the 0 position). Considering the thickness of the counterweight block 3 is relatively thin, R 块 The value can be directly taken as the radius value of the power turbine shaft 1. The diameter size of the power turbine shaft at this point in this embodiment is Therefore R 块 The value is 19.1mm.

[0055] Weigh the mass of the counterweight 3 and substitute the relevant data into the above formula for the length of the material removed by the third and second jaws 21 to obtain the final length of the material removed. Figure 6 As shown, the corresponding claws 21 on the balancing weight ring 2 are removed, and the removal tolerance is ±0.1mm.

[0056] The above-mentioned relationship coefficient k and removal coefficient t are empirical coefficients obtained by the present invention through many trials and tribulations.

[0057] Example 2

[0058] This embodiment describes the detection of the deflection value of the power turbine shaft: the detection of the deflection value is achieved by arranging a plurality of displacement sensors on the power turbine shaft 1 for measuring the vibration displacement of the power turbine in the axial direction and the radial direction.

[0059] like Figure 8 As shown, there are four displacement sensors in total. Specifically, displacement sensors D3 and D4 are provided on the outer periphery of the power turbine shaft 1 corresponding to the position where the four claws of the balance weight ring 2 begin to extend. The D3 and D4 displacement sensors are located in the same cross-section. In addition, along the axial direction of the power turbine shaft 1, displacement sensors D1 and D2 are provided on both sides of the balance weight ring 2. In this embodiment, the D1 displacement sensor is 350 mm away from the D3 displacement sensor, and the D2 displacement sensor is 300 mm away from the D3 displacement sensor.

[0060] The D1, D2 and D3 displacement sensors measure the vibration displacement of the power turbine shaft 1 in the vertical direction (i.e., radial direction) from top to bottom, and the D4 displacement sensor measures the vibration displacement of the power turbine shaft 1 in the horizontal direction (i.e., axial direction) from left to right (looking from the power turbine disk end to the output end).

[0061] Example 3

[0062] The present invention also provides a method for performing high-speed dynamic balancing correction on a power turbine shaft using the balancing weight ring removal method in Examples 1 and 2, comprising the following steps:

[0063] S1. Before the high-speed dynamic balancing test of the power turbine shaft 1, a rivet hole on the balance weight ring 2 is marked as 0, and the positions of 0 degrees, 90 degrees, 180 degrees, and 270 degrees are marked;

[0064] S2. Perform a high-speed dynamic balancing test on the power turbine shaft 1, focusing on the deflection values ​​at measuring points D3 and D4. When the deflection value exceeds 250 μm, observe the deflection value and angular position corresponding to the critical speed. After the test is stopped, add counterweights 3 to the outer periphery of the power turbine shaft 1.

[0065] S3. Start the high-speed dynamic balancing test to confirm whether the deflection value is within 250um after the counterweight 3 is installed. If it is satisfied, stop the test; if not, continue to add the counterweight 3 until it is satisfied;

[0066] S4. Weigh the mass of the added counterweight 3, confirm the setting position of the counterweight 3, and calculate the length L of the corresponding claw 21 of the balance weight ring 2. n ;

[0067] S5 decomposition of the blind rivet 4, remove the balancing weight ring 2, remove the process to ensure that the balancing weight ring 2 angle to substantially unchanged, determine the serial number of the claw 21;

[0068] S6. Remove the material L on the corresponding claw 21. n ;

[0069] S7. Reinstall the balance weight ring 2 as it was in position, and tighten the blind rivet 4;

[0070] S8. Perform a high-speed dynamic balancing test again to verify whether the test after removing the material matches the expected data when installing the counterweight block 3, and whether the deflection value meets the design requirements.

[0071] If the deflection value verified by S8 still does not meet the design requirements, S2 to S8 need to be repeated.

[0072] The present invention's balancing weight ring removal method and high-speed dynamic balancing correction method ensure that, after removing a certain length of material from the corresponding jaws of the balancing weight ring during testing, the deflection value at the critical speed remains within the acceptable range, and a corresponding relationship is established. This method essentially ensures that a single removal of the balancing weight ring results in a successful deflection correction, reducing the frequency of repeated disassembly and assembly and testing costs. This method provides a reference for high-speed balancing deflection correction of slender shafts with built-in balancing weight rings.

[0073] Obviously, the above embodiments are merely examples for the purpose of clearly illustrating the technical solutions of the present invention, and are not intended to limit the implementation methods of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A method for removing the balancing weight ring for high-speed dynamic balancing of a slender shaft, characterized in that , a counterweight is set at the corresponding angular position of the deflection value corresponding to the critical speed of the slender shaft. The length L of the balance weight ring is: Where m is the mass of the counterweight, R 块 R is the axial radius of the counterweight block. 环 is the mass radius of the balancing weight ring, k is the coefficient of the relationship between the length of the balancing weight ring removed and the mass of the removed material, k = 0.295; Then decompose the torque of the counterweight block to the 45° direction of the center of the balance weight ring claw, and remove the corresponding claw in the opposite direction of the balance weight ring. The corresponding claw removal length L n For: L n =L×B×t, where B is the trigonometric function relationship between the angular direction of the counterweight block and the 45° direction of the center of the balance weight ring claw, t is the material removal coefficient, t=1.4, and n is the claw number.

2. The method for removing the balancing weight ring for high-speed dynamic balancing of a slender shaft according to claim 1, characterized in that: The removal tolerance of the corresponding claws on the balancing weight ring is ±0.1mm.

3. The method for removing the balancing weight ring for high-speed dynamic balancing of a slender shaft according to claim 1, characterized in that: The counterweight is a lead block.

4. The method for removing the balancing weight ring for high-speed dynamic balancing of a slender shaft according to claim 1 or 3, characterized in that: The counterweight block is an arc-shaped thin block.

5. The method for removing the balancing weight ring for high-speed dynamic balancing of a slender shaft according to claim 4, characterized in that: R 块 The value is the radius of the slender axis.

6. The method for removing the balancing weight ring for high-speed dynamic balancing of a slender shaft according to claim 1, characterized in that: The counterweight is fixed on the elongated shaft by a binding strap or an adhesive tape.

7. The method for removing the balancing weight ring for high-speed dynamic balancing of a slender shaft according to claim 1, characterized in that: The detection of the deflection value of the slender shaft is achieved by arranging a plurality of displacement sensors on the slender shaft for measuring the vibration displacement of the slender shaft in the axial direction and the radial direction.

8. The method for removing the balancing weight ring for high-speed dynamic balancing of a slender shaft according to claim 7, characterized in that: There are four displacement sensors, two of which are arranged on the outer periphery of the slender shaft corresponding to the positions where the four claws of the balancing weight ring begin to extend, and are used to measure the vibration displacement in the axial direction and radial direction of the slender shaft respectively. The remaining two displacement sensors are used to measure the vibration displacement in the axial direction of the slender shaft, and are distributed on both sides of the balancing weight ring along the axial direction of the slender shaft.

9. A method for high-speed dynamic balance correction of a slender shaft using the balancing weight ring removal method according to any one of claims 1 to 8, characterized in that: The steps include: S1. Before performing a high-speed dynamic balancing test on a slender shaft, mark the 0, 90, 180, and 270-degree positions, using a rivet hole on the balancing weight ring as the zero position. S2. Perform a high-speed dynamic balancing test on the slender shaft, focusing on the deflection. When the deflection exceeds 250 μm, observe the deflection and angular position corresponding to the critical speed. After stopping the test, add counterweights to the outer periphery of the slender shaft. S3. Start the high-speed dynamic balancing test to confirm whether the deflection value is within 250μm after the counterweight is installed. If it is satisfied, stop the test; if not, continue to add counterweights until it is satisfied. S4. Weigh the added counterweight, confirm the counterweight position, and calculate the length L of the corresponding claws of the balance weight ring. n ; S5. Remove the balancing weight ring. Ensure that the angular direction of the balancing weight ring remains unchanged during the removal process and determine the claw number. S6. Remove material L on the corresponding jaws n ; S7. Reinstall the balancing weight ring; S8. Conduct high-speed dynamic balancing test again to verify whether the deflection value after material removal meets the design requirements.

10. The method for high-speed dynamic balance correction of a slender shaft according to claim 9, characterized in that: If the deflection value verified by S8 still does not meet the design requirements, S2 to S8 need to be repeated.

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