A process for manufacturing a metal spacer for a flexible bearing of a tiltrotor system

Abstract

This invention discloses a manufacturing process for metal spacers of elastic bearings for tiltrotor systems in the field of high-end equipment manufacturing technology, including the following steps: Step 1) Blanking: Prepare metal blanks and cut them to the required dimensions; Step 2) Cleaning the mold and blanks with alcohol: Clean the drawing mold and the metal blanks; Step 3) Installing the mold and debugging: Install the cleaned metal blanks in the drawing mold and perform debugging; Step 4) Spraying high-temperature lubricant on the mold and blanks: Spray high-temperature lubricant on the mold and the metal blanks; Step 5) Heating the mold and placing the blanks to reach the target temperature and holding it at that temperature for a set time; Step 6) Pressurizing and holding the pressure: Under the action of the upper die head, the metal blanks undergo hot drawing deformation inside the mold; Step 7) Depressurizing and removing the blanks for cooling; Step 8) Cutting and shaping; This invention solves the problems of wrinkling, cracking, uneven thickness, and non-compliant dimensional accuracy that easily occur in existing metal spacers during the forming process.

Description

Technical Field

[0001] This invention relates to the field of high-end equipment manufacturing technology, and in particular to an elastic bearing for a tiltrotor system. Background Technology

[0002] The existing articulated rotor is the traditional rotor type, and this form has matured and accumulated considerable experience through long-term application. However, due to its complex structure, high maintenance workload, relatively poor safety, and inherent drawbacks such as low longitudinal efficiency and low angular velocity damping, this form is far from ideal. Therefore, research into hingeless rotors has begun. In the 1960s, the idea of ​​using elastic bearings to simplify the rotor hub was proposed by Americans.

[0003] As disclosed in the prior art, a tiltrotor rotor hub system (publication number CN 115924071 A) features a key component of its elastic bearing: a laminated elastomer composed of metal spacers and rubber. The metal spacers and rubber are combined to form the elastomer. The elastic bearing withstands the centrifugal force and flapping loads of the rotor blades through the compressive and radial load-bearing capacity of the laminated elastomer, and achieves relative torsional and bending moment deformation through the shear deformation of the rubber within the laminated elastomer. Each pair of thin rubber layers is separated by a metal sheet and vulcanized together.

[0004] As a key component of elastic bearings, the dimensional accuracy and fatigue characteristics of the metal spacer directly affect the bearing's performance. Elastic bearing metal spacers are hemispherical, thin-walled parts, and the forming process presents challenges such as wrinkling, cracking, uneven thickness, and substandard dimensional accuracy. The dimensional accuracy and fatigue performance of the metal spacer are closely related to its forming process; therefore, the forming process is a crucial factor directly influencing the performance of elastic bearings. Because elastic bearings are inherently highly elastic, with elastic deformation typically five to ten times the original size, and because the movement of the elastic bearing relies on the shear deformation of the rubber layer, high consistency in the forming of the metal parts is essential to ensure uniformity and isotropy of the rubber layer material. Inconsistencies in the metal sheet can lead to torsional deformation of the rubber layer, resulting in variations in the load-bearing area. Uniform metal sheets ensure more uniform strain across the rubber layers, resulting in a more even stress distribution, effectively reducing stress gradients between layers, preventing premature failure of localized layers, and improving the overall fatigue life of the bearing. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a manufacturing process for metal spacers of elastic bearings for tilt rotor systems, which solves the problems of wrinkling, cracking, uneven thickness, and substandard dimensional accuracy that easily occur in existing metal spacers during the molding process.

[0006] The objective of this invention is achieved as follows: a process for manufacturing a metal spacer for a resilient bearing in a tiltrotor system, comprising the following steps:

[0007] Step 1) Cutting: Prepare the metal blank and cut it to the required size;

[0008] Step 2) Clean the mold and blank with alcohol: Clean the deep drawing mold and metal blank to ensure the surface is clean;

[0009] Step 3) Install and adjust the mold: Install the cleaned metal blank in the deep drawing mold and perform adjustment work. Adjust the clamping force of the clamping mold so that it can meet the clamping operation and also allow the metal blank to slide between the clamping mold during deep drawing.

[0010] Step 4) Spraying high-temperature lubricant on molds and blanks: Spray high-temperature lubricant on molds and metal blanks;

[0011] Step 5) Heating the mold to place the blank to the target temperature and holding it at that temperature for a set time: Heating the mold containing the metal blank to the target temperature and holding it at that temperature for a set time.

[0012] Step 6) Pressurization and holding pressure: Apply pressure to the heated upper die head, and at the same time control the upper die head to rotate and press down. Under the action of the upper die head, the metal blank is thermally drawn and deformed inside the mold. After the upper die head rotates and presses down to the set position, it is held in a pressure-holding state for a set time.

[0013] Step 7) Depressurize, remove and cool: After depressurizing, control the upper die head to rise and remove the metal spacer that has been hot-drawn and then cool it.

[0014] Step 8) Cutting and shaping: The bowl-shaped metal spacer is machined to obtain the metal spacer of the elastic bearing.

[0015] As a preferred technical solution for the manufacturing process of the metal spacer of the elastic bearing for the tilt rotor system described in this invention, the metal blank is made of aluminum alloy, titanium alloy, magnesium alloy, stainless steel or a combination thereof.

[0016] As a preferred technical solution for the manufacturing process of the metal spacer of the elastic bearing for the tilt rotor system described in this invention, the metal blank is a circular sheet structure, the lower end of the upper die head is a ball head structure, and the clamping die is provided with corresponding slots.

[0017] As a preferred technical solution for the manufacturing process of the metal spacer of the elastic bearing for the tilt rotor system described in this invention, the high-temperature lubricant in step 4) is MoS2 high-temperature solid lubricant.

[0018] As a preferred technical solution for the manufacturing process of the metal spacer of the elastic bearing for the tilt rotor system described in this invention, the mold heating temperature in step 5) is 600℃ to 800℃, and the temperature is maintained for 10±1min.

[0019] As a preferred technical solution for the manufacturing process of the metal spacer of the elastic bearing for the tilt rotor system described in this invention, the pressure of the clamping mold is:

[0020] Pc = k×E×(Hhb)×α×(T-T0) / h

[0021] Where k is an empirical coefficient, ranging from 1.5 to 2.5, E is the elastic modulus of the mold material, H is the total height of the mold, h is the cavity height, b is the height of the upper die head, α is the linear expansion coefficient of the material, T is the heating temperature, and T0 is the ambient temperature; and satisfy the following: during the hot drawing process, the metal blank is fixed between the upper and lower templates, the compressive stiffness between the upper and lower templates is much greater than the bending stiffness of the upper template, the upper template deforms downward due to thermal expansion, the upper die head is constrained due to thermal expansion, the deformation stops when the stress at the upper die head reaches the yield strength of the material, the clamping pressure needs to be greater than the stress caused by thermal expansion, the stress is proportional to the amount of thermal expansion, and the amount of thermal expansion is proportional to the temperature rise and the mold height.

[0022] As a preferred technical solution for the manufacturing process of the metal spacer of the elastic bearing for the tilt rotor system described in this invention, the rotation speed of the upper mold head is 10 rpm.

[0023] Compared with the prior art, the present invention has the following technical effects:

[0024] Dimensional accuracy: Through the process of this invention, the metal spacer can achieve high-precision dimensional requirements, ensuring the assembly and operation accuracy of the elastic bearing;

[0025] Fatigue properties: By using a forming process that combines heating, appropriate clamping, and rotational pressure, its fatigue performance can be improved, giving it a longer service life.

[0026] Forming consistency: This invention enables precise control of parameters such as the shape, thickness, and size of the metal spacer, ensuring the isotropy and uniform strain distribution of the elastic bearing;

[0027] Uniformity of bearing area: High-precision dimensions ensure uniform metal spacers. Uniform metal spacer molding can reduce the stress gradient between adhesive layers, avoid premature failure of local adhesive layers, and thus improve the overall fatigue life of elastic bearings.

[0028] In summary, by optimizing the forming process of metal spacers, metal spacers with high dimensional accuracy, excellent fatigue performance, good forming consistency, and uniform bearing area can be obtained, thereby improving the performance and service life of elastic bearings. Attached Figure Description

[0029] 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. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0030] Figure 1 This is a flowchart of the present invention.

[0031] Figure 2 This is a schematic diagram of the mold structure in this invention.

[0032] Figure 3 This is a cross-sectional view of the mold in this invention.

[0033] Among them, there is a 100 upper template, a 200 lower template, and a 300 upper mold head. Detailed Implementation

[0034] 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] like Figure 1-3 The manufacturing process of a metal spacer for a resilient bearing in a tiltrotor system, as shown, includes the following steps:

[0036] Step 1) Cutting: Prepare metal blanks and cut them according to the required size. The metal blanks are made of aluminum alloy, titanium alloy, magnesium alloy, stainless steel or a combination thereof. In this embodiment, 6061 aluminum alloy sheet with a thickness of 8mm is selected. The metal blanks are in the shape of round pieces. The lower end of the upper die head 300 is a ball head structure. The clamping die is provided with corresponding slots.

[0037] Step 2) Cleaning the mold and blank with alcohol: Clean the drawing mold and metal blank to ensure the surface is clean. Clean the mold and blank by ultrasonic cleaning the drawing mold and 6061 aluminum alloy blank with alcohol solution.

[0038] Step 3) Die Installation and Adjustment: Install the cleaned metal blank into the drawing die and perform adjustments. Adjust the clamping force of the clamping die to ensure that it can both hold the metal blank during the drawing process and allow sliding between the metal blank and the clamping die. The clamping pressure is (the figure is for illustrative purposes only and the dimensions are not the exact dimensions shown):

[0039] Pc = k×E×(H - h - b)×α×(T - T0) / h

[0040] Where k is an empirical coefficient, ranging from 1.5 to 2.5, E is the elastic modulus of the mold material, H is the total height of the mold, h is the cavity height, b is the height of the upper die head 300, α is the linear expansion coefficient of the material, T is the heating temperature, and T0 is the ambient temperature; and satisfy the following: during the hot drawing process, the metal blank is fixed between the upper die plate 100 and the lower die plate 200, the compressive stiffness between the upper die plate 100 and the lower die plate 200 is much greater than the bending stiffness of the upper die plate 100, the upper die plate 100 deforms downward due to thermal expansion, the upper die head 300 is constrained due to thermal expansion, and the deformation stops when the stress at the upper die head 300 reaches the yield strength of the material, the clamping pressure needs to be greater than the stress caused by thermal expansion, the stress is proportional to the amount of thermal expansion, and the amount of thermal expansion is proportional to the temperature rise and the mold height;

[0041] Step 4) Spraying high-temperature lubricant on molds and blanks: Spraying MoS2 high-temperature solid lubricant on molds and metal blanks;

[0042] Step 5) Heating the mold and placing the blank to the target temperature and holding it for a set time: Heating the mold containing the metal blank to 600℃ to 800℃ and holding it at that temperature for 10±1min.

[0043] Step 6) Pressurization and holding pressure: Apply pressure to the heated upper die head 300, and simultaneously control the upper die head 300 to rotate and press down. Under the action of the upper die head 300, the metal blank undergoes hot drawing deformation inside the mold. After the upper die head 300 rotates and presses down to the set position, it is held in a pressure holding state for a set time. The upper die head 300 applies a pressure of 2MPa and a rotation speed of 10rpm. After rotating and pressing down to a depth of 20mm, it holds the pressure for 30s.

[0044] Step 7) Depressurize, remove and cool: After depressurizing, control the upper die head to rise 300 degrees, remove the metal partition formed by hot drawing, and perform cooling treatment;

[0045] Step 8) Cutting and shaping: The bowl-shaped metal spacer is machined to obtain the metal spacer of the elastic bearing.

[0046] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A process for making a metal spacer for a resilient bearing of a tiltrotor system, characterized in that, The method comprises the following steps: Step 1) blanking: preparing a metal blank and blanking according to the required size; Step 2) alcohol cleaning of the mold and the blank: cleaning the drawing mold and the metal blank to ensure the surface is clean; Step 3) installation of the mold and debugging: installing the cleaned metal blank in the drawing mold and performing debugging work, and adjusting the clamping force of the clamping mold so that it can meet the clamping operation and realize the sliding between the metal blank and the clamping mold during drawing; Step 4) spraying of high-temperature lubricant on the mold and the blank: spraying a high-temperature lubricant on the mold and the metal blank; Step 5) heating of the mold with the blank to the target temperature and holding for a set time: heating the mold with the metal blank to the target temperature and keeping the temperature stable for a set time, the heating temperature of the mold in step 5) is 600-800℃, and the holding time is 10±1 min; Step 6) pressure forming and pressure holding: applying pressure to the heated upper die head while controlling the rotation and downward pressing of the upper die head, so that the metal blank is deformed by hot drawing in the mold under the action of the upper die head, and the upper die head is kept in a set position after rotating and downward pressing for a set holding time; Step 7) pressure relief, taking out and cooling: after pressure relief, the upper die head is controlled to rise, the metal spacer formed by hot drawing is taken out, and cooling treatment is performed; Step 8) cutting and forming, the bowl-shaped metal spacer is machined to obtain a metal spacer of an elastic bearing; The pressure of the clamping mold is: Pc = k×E×(H - h - b)×α×(T - T0) / h Wherein, k is an empirical coefficient, the value is 1.5-2.5, E is the elastic modulus of the mold material, H is the total height of the mold, h is the cavity height, b is the height of the upper die head, α is the linear expansion coefficient of the material, T is the heating temperature, T0 is the environmental temperature; and it satisfies: the metal blank is fixed between the upper and lower mold plates during hot drawing, the compressive stiffness between the upper and lower mold plates is much larger than the bending stiffness of the upper mold plate, the upper mold plate is deformed downward due to thermal expansion, the upper die head is constrained due to thermal expansion, the stress at the upper die head reaches the yield strength of the material when the deformation stops, the clamping pressure needs to be greater than the stress caused by thermal expansion, the stress is proportional to the thermal expansion, and the thermal expansion is proportional to the temperature rise and the height of the mold; The rotation speed of the upper die head is 120-150 rpm.

2. The process for manufacturing a metal shim for a compliant bearing of a tiltrotor system according to claim 1, characterized in that, The metal blank is made of aluminum alloy, titanium alloy, magnesium alloy, stainless steel or a combination thereof.

3. A process for manufacturing a metal shim for an elastomeric bearing of a tiltrotor system according to claim 1 or 2, characterized in that, The metal blank is in a round sheet structure, the lower end of the upper die head is in a ball head structure, and a corresponding slot hole is arranged on the clamping mold.

4. The process for manufacturing a metal shim for an elastomeric bearing of a tiltrotor system according to claim 1 or 2, characterized in that, The high-temperature lubricant in step 4) is MoS2 high-temperature solid lubricant.

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