Friction piece for aircraft main speed reducer and preparation method of friction piece

Abstract

The invention relates to the field of manufacturing of friction pieces for aerospace crafts, in particular to a friction piece for a main speed reducer of an aircraft and a preparation method of the friction piece. The friction piece is of a sandwich structure, the sandwich structure comprises a functional layer, an interface layer and an alloy structure layer, the interface layer is attached to the alloy structure layer, and the functional layer is attached to the interface layer; the functional layer is made of a copper-based friction material, and the copper-based friction material is prepared from, by mass, 50%-58% of pure copper powder, 2%-8% of bronze powder, 8%-18% of iron powder, 2%-5% of nickel powder, 16%-19% of graphite powder and 1%-3% of CrFe powder. The interface layer is a copper / nickel plating layer; the alloy structure layer is a steel structure layer, and the nickel plating layer in the interface layer is in direct contact with the steel structure layer. The material is reasonable in component design, the preparation process is simple and controllable, the obtained product is excellent in performance, and industrial application is facilitated.

Description

Technical Field

[0001] This invention relates to the field of friction component manufacturing for aerospace vehicles, specifically to a friction component for a main reducer of an aircraft and its preparation method. Background Technology

[0002] Modern aircraft face increasingly stringent performance requirements, such as more complex flight attitudes, longer service life, more precise control, and more frequent start-stop operations. Friction components, as key parts of the aircraft's main gearbox, are braked and locked by applying braking force to the friction components according to the output commands from the attitude servo mechanism, thereby manipulating other mechanisms to adjust the attitude in response. Therefore, friction components used in aircraft main gearboxes must possess excellent properties such as high reliability, high wear resistance, and long service life.

[0003] Traditional speed reducer friction components are generally made of copper alloys or copper-based ceramic metals. For example, patent CN114082941A involves a spherical ceramic particle copper-based powder metallurgy friction material and its preparation method. This patent describes a spherical ceramic particle copper-based powder metallurgy friction material made from the following percentages of raw materials: 40%–60% copper powder, 10%–20% iron powder, 5%–15% ferrochrome powder, 5%–15% graphite, 2%–5% molybdenum disulfide, 1%–8% spherical ceramic particles, 1%–5% chromium powder, and 1%–5% nickel powder. The resulting product has room for improvement in shear strength and does not address the average stability coefficient of the product. Patent RU2800902C1 involves the use of 10–15% tin bronze in the friction material, but it also does not address improving the stability coefficient.

[0004] With the increasing power and complexity of service environments in aircraft, the insufficient strength and self-lubricating ability of copper alloys lead to severe damage such as chipping and fracture under dry operation and long-term service conditions, seriously affecting aircraft safety. Therefore, existing copper alloys cannot meet the various performance requirements of aircraft, and the development of friction components with both high strength and self-lubricating properties is urgently needed. However, there are currently no reports on relevant technologies for friction components used in aircraft main gearboxes. Summary of the Invention

[0005] This invention addresses the shortcomings of existing technologies by providing, for the first time, a wear-resistant friction component with a sandwich structure and a stability coefficient greater than 0.95 for the main deceleration gearbox of an aircraft.

[0006] This invention discloses a friction component for an aircraft main decelerator. The friction component has a sandwich structure, comprising a functional layer, an interface layer, and an alloy structure layer. The interface layer is attached to the alloy structure layer, and the functional layer is attached to the interface layer. The functional layer is made of a copper-based friction material, the raw materials of which, by mass percentage, consist of the following components: 50-58% pure copper powder, 2-8% bronze powder, 8-18% iron powder, 2-5% nickel powder, 16-19% graphite powder, and 1-3% CrFe powder. The interface layer is a copper / nickel plating. The alloy structure layer is a steel structure layer, and the nickel plating in the interface layer is in direct contact with the steel structure layer.

[0007] The total thickness of the copper / nickel plating is 180~300 micrometers, preferably 195~205 micrometers, wherein the ratio of the thickness of the copper plating to the thickness of the nickel plating is 0.8~1.2:0.8~1.2, preferably 1:1. The nickel plating is in direct contact with the alloy structural layer.

[0008] This invention employs a structural design of a functional layer, an interface layer, and an alloy structure layer, ensuring that the friction components possess both the high strength of the alloy structure layer and the frictional stability and self-lubricating wear resistance of the copper-based friction material. Under continuous braking conditions simulating an aircraft's main decelerator, it exhibits excellent performance and fully meets the operating conditions of the aircraft's main decelerator.

[0009] This invention discloses a friction component for an aircraft main reducer, which features a sandwich structure design of a functional layer, an interface layer, and an alloy structure layer, enabling the friction component to meet the service requirements of the aircraft's main drive motor.

[0010] Preferably, the functional layer of the friction component for the main deceleration unit of an aircraft according to the present invention is made of copper-based friction material.

[0011] Preferably, the friction component for the main deceleration gearbox of an aircraft of the present invention comprises, by mass percentage, the raw material composition of the copper-based friction material of its functional layer as follows: 54-56% pure copper powder, 3-5% bronze powder, 16-18% iron powder, 3-5% nickel powder, 17-19% graphite powder, and 1.5-2.5% CrFe powder.

[0012] Preferably, the friction component for an aircraft main reducer of the present invention comprises, by mass percentage, the following components in the copper-based friction material of its functional layer: 55% pure copper powder, 4% bronze powder, 17% iron powder, 4% nickel powder, 18% graphite powder, and 2% CrFe powder. The resulting friction component for the aircraft main reducer exhibits high friction curve stability and low wear, fully meeting the requirements for aircraft use.

[0013] Preferably, the friction component for the main deceleration gearbox of an aircraft according to the present invention uses tin bronze. As a further preferred embodiment, the bronze powder composition, by mass percentage, comprises the following components: copper 90-95%, Sn 4.5-8%, and Zn 0.5-2%.

[0014] In this invention, the particle size of the pure copper powder is 200-300 mesh.

[0015] In this invention, the particle size of the bronze powder is 200-300 mesh.

[0016] In this invention, the particle size of the iron powder is 200-300 mesh.

[0017] In this invention, the particle size of the nickel powder is 200-300 mesh.

[0018] In this invention, the particle size of the graphite powder is 60-100 mesh.

[0019] In this invention, the CrFe alloy powder has a particle size of 150-250 mesh.

[0020] Preferably, the interface layer of the friction component for the main deceleration unit of an aircraft according to the present invention is a copper / nickel plating layer.

[0021] Preferably, the alloy structural layer of the friction component for the main deceleration unit of an aircraft according to the present invention comprises 45 steel.

[0022] This invention discloses a method for manufacturing a friction component for an aircraft main deceleration unit, comprising the following steps:

[0023] (1) Mixing raw materials for functional layer materials: Copper powder, bronze powder, iron powder, nickel powder, graphite powder and CrFe powder are mixed according to the designed composition; 3-5% of the total mass of the mixed powder is added to kerosene and mixed by a roller to obtain uniform powder.

[0024] (2) Functional layer material compression molding: The powder mixed evenly in (1) is added into the mold and cold-pressed to obtain the molded blank. The molding pressure is 10-15MPa and the holding time is 5-10s.

[0025] (3) Preparation of copper / nickel plating on steel surface: Copper / nickel electroplating is performed on the surface of No. 45 steel alloy structure layer. The copper / nickel thickness ratio is 1:(1-2) and the plating thickness is 100~300µm to obtain the copper / nickel interface layer and steel alloy structure layer of friction part.

[0026] (4) Friction component assembly: The functional layer material is placed on top of the interface layer and the alloy structure layer, and the outer ring is fixed with tape.

[0027] (5) Friction component sintering: The assembled friction component is placed in a pressure sintering furnace under a protective atmosphere. The sintering temperature is 780-850 ℃, the pressure is 1.5-2.5 MPa, and the holding time is 2-3 hours. Then, it is cooled with the furnace to obtain the friction component for the main reducer of the aircraft.

[0028] In this invention, the interface layer is prepared as follows: A clean and dry steel surface is placed in a nickel sulfate plating solution, which consists of 240-300 g / L NiSO4·6H2O, 40-60 g / L NiCl2·6H2O, and 30-40 g / L H3BO3, with a current density of 2-5 A / dm³. 2 The plating time is 1.5–4 hours to deposit a nickel layer. The preferred plating solution consists of 280 g / L NiSO4·6H2O, 50 g / L NiCl2·6H2O, and 35 g / L H3BO3, with a current density of 3 A / dm³. 2 The time was 2.5 hours, and a nickel layer was deposited.

[0029] In this invention, nickel-plated steel is placed in a copper sulfate plating solution, which consists of 180-220 g / L CuSO4·5H2O and 50-60 g / L H2SO4, with a current density of 1-3 A / dm³. 2 The time is 1.5–4 hours to deposit a copper layer. Preferably, the nickel-plated steel is placed in a copper sulfate plating solution composed of 200 g / L CuSO4·5H2O and 55 g / L H2SO4, with a current density of 2 A / dm³. 2 Copper layer was deposited over a period of 2 hours.

[0030] In step (2) of this invention, the powder that was mixed evenly in (1) is added into a mold and cold-pressed to obtain a blank. The molding pressure is 10~15MPa and the holding time is 1-30s.

[0031] Preferably, in step (5) of the present invention, the sintering temperature is 815~825 ℃, the pressure is 1.9~2.1MPa, and the holding time is 145~160min.

[0032] After optimization, the friction component for the main decelerator of an aircraft designed and manufactured in this invention has an average friction coefficient of 0.25, an average friction stability coefficient of 0.97, an average wear amount per cycle of 0.0013 cm3, and an average friction coefficient greater than 0.23 and a stability coefficient greater than 0.96 within 80 to 100 cycles.

[0033] Beneficial effects

[0034] This invention constructs a sandwich structure for the friction component, employing a design consisting of a functional layer made of copper-based friction material, a copper / nickel interface layer, and a steel alloy structural layer. This ensures that the friction component possesses both the high strength of the alloy structural layer and the frictional stability and self-lubricating wear resistance of the copper-based friction material. The manufacturing process of this invention is simple and efficient. The invented friction component breaks through the strength limit of a single copper-based friction material, compensates for the lack of self-lubricating wear resistance in alloys, and the interface layer between the functional and structural layers gives the friction component excellent shear strength and good interfacial bonding performance. In simulated aircraft main deceleration under continuous braking conditions, it exhibits excellent performance, a long service life, and fully meets the operating conditions of aircraft main deceleration.

[0035] During the sintering process, Sn and Zn in the bronze powder in the functional layer form a diffusion solid solution with the copper / nickel interface layer, which greatly improves the bonding strength between the functional layer and the interface layer and ensures the service stability of the friction component. Attached Figure Description

[0036] Figure 1 The graph shows the coefficient of friction of the product obtained in Example 1. Detailed Implementation

[0037] This invention provides a friction component for an aircraft main reducer and its manufacturing method, which demonstrates excellent braking performance by simulating the braking conditions of the aircraft's main drive motor.

[0038] The test machine for the main reducer of the simulated flight vehicle of this invention is the MM1000 test machine. The friction pair material is 30CrMnVA alloy steel, the rotation speed is 1800 rpm, the braking pressure is 0.8 MPa, the inertia is 1.05 kg·m², the single test time is 5 minutes, and the number of tests is 100.

[0039] The average friction coefficient is the average of the instantaneous friction coefficients throughout the entire friction cycle. The friction stability coefficient is the quotient of the average friction coefficient and the highest instantaneous friction coefficient.

[0040] The interface layer is prepared as follows: steel is placed in a nickel sulfate plating solution, which consists of 240-300 g / L NiSO4·6H2O, 40-60 g / L NiCl2·6H2O, and 30-40 g / L H3BO3, with a current density of 2-5 A / dm³. 2 The time is 1.5 to 4 hours, and a nickel layer is deposited.

[0041] Nickel-plated steel is placed in a copper sulfate plating solution, which consists of 180-220 g / L CuSO4·5H2O and 50-60 g / L H2SO4, with a current density of 1-3 A / dm³. 2 The time is 1.5 to 4 hours, and a copper layer is deposited.

[0042] Example 1

[0043] (1) Mixing of raw materials for functional layer materials: According to the designed composition (mass percentage), prepare 55% copper powder (particle size: 200~300 mesh), 4% bronze powder (particle size: 200-300 mesh; it is composed of 93.1wt% copper, 5.4wt% Sn, and 1.5wt% Zn), 17% iron powder (particle size: 200~300 mesh), 4% nickel powder (particle size: 200-300 mesh), 18% graphite (particle size: 60~100 mesh), and 2% CrFe alloy powder (particle size: 200-250 mesh); then add 5% kerosene of the total mass of the prepared powders, and mix them in a roller to obtain uniform powder.

[0044] (2) Functional layer material compression molding: The powder mixed evenly in (1) is added into the mold and cold-pressed to obtain the molded blank. The molding pressure is 12MPa and the holding time is 7s.

[0045] (3) Preparation of copper / nickel plating on steel surface: Copper / nickel electroplating treatment was performed on the surface of No. 45 steel with alloy structural layer: The steel was placed in nickel sulfate plating solution, which consisted of 280 g / L NiSO4·6H2O, 50 g / L NiCl2·6H2O, and 35 g / L H3BO3, with a current density of 3A / dm. 2 The time was 2.5 hours, and a nickel layer was deposited.

[0046] Nickel-plated steel was placed in a copper sulfate plating solution composed of 200 g / L CuSO4·5H2O and 55 g / L H2SO4, with a current density of 2 A / dm³. 2 The deposition process took 2 hours, during which a copper layer was deposited. The coating thickness was 200 µm (100 µm copper / 100 µm nickel), resulting in a copper / nickel interface layer and a steel alloy structural layer for the friction component.

[0047] (4) Friction component assembly: The functional layer material is placed on top of the interface layer and the alloy structure layer, and the outer ring is fixed with tape.

[0048] (5) Friction component sintering: Under a protective atmosphere, the assembled friction component blank is placed in a pressure sintering furnace at a sintering temperature of 820 ℃, a pressure of 2MPa, and a holding time of 2.5 hours. Then, it is cooled with the furnace to obtain a copper-based friction component for braking the main drive motor of the aircraft.

[0049] (6) Test results:

[0050] The friction component for the main deceleration unit of an aircraft obtained in this embodiment has a Brinell hardness of 18 HB and an interfacial shear strength of 58 MPa.

[0051] The friction component for the main gearbox of the aircraft obtained in this embodiment, under simulated braking conditions of the main gearbox, has an average friction coefficient of 0.25, an average friction stability coefficient of 0.97, and an average wear amount per cycle of 0.0013 cm. 3 On average, the friction coefficient is greater than 0.23 and the stability coefficient is greater than 0.96 within 80 to 100 cycles.

[0052] Example 2

[0053] The conditions are the same as in Example 1, except that: copper powder 54% (particle size: 200~300 mesh) and CrFe alloy powder 3% (particle size: 200-250 mesh);

[0054] Test results:

[0055] The friction component for the main deceleration unit of an aircraft obtained in this embodiment has a Brinell hardness of 20 HB and an interfacial shear strength of 50 MPa in its functional layer material.

[0056] The friction component for the main gearbox of the aircraft obtained in this embodiment, under simulated braking conditions of the main gearbox, has an average friction coefficient of 0.26, an average friction stability coefficient of 0.96, and an average wear amount per cycle of 0.0017 cm. 3 Within 80 to 100 cycles, the friction coefficient is greater than 0.24 and the stability coefficient is greater than 0.95.

[0057] Example 3

[0058] The conditions are the same as in Example 1, except that in the coating preparation process, the steel is placed in a nickel sulfate plating solution composed of 280 g / L NiSO4·6H2O, 50 g / L NiCl2·6H2O, and 35 g / L H3BO3, with a current density of 3 A / dm³. 2 A nickel layer was deposited in 2.71 hours.

[0059] Nickel-plated steel was placed in a copper sulfate plating solution, which consisted of 200 g / L CuSO4·5H2O and 55 g / L H2SO4, with a current density of 2 A / dm³. 2 The deposition time was 2 hours, and a copper layer was deposited. The coating thickness was 250 µm (100 µm copper / 150 µm nickel).

[0060] Test results:

[0061] The friction component for the main deceleration unit of an aircraft obtained in this embodiment has a Brinell hardness of 18HB and an interfacial shear strength of 58MPa.

[0062] The friction component for the main gearbox of the aircraft obtained in this embodiment, under simulated braking conditions of the main gearbox, has an average friction coefficient of 0.27, an average friction stability coefficient of 0.96, and an average wear amount per cycle of 0.0018 cm. 3 Within 80 to 100 cycles, the friction coefficient is greater than 0.22 and the stability coefficient is greater than 0.95.

[0063] Example 4

[0064] The conditions are the same as in Example 1, except that: copper powder 54% (particle size: 200-300 mesh) and bronze powder 5% (particle size: 200-300 mesh; composed of 93.1wt% copper, 5.4wt% Sn, and 1.5wt% Zn); in the coating preparation process, the steel is placed in a nickel sulfate plating solution, which consists of 280 g / L NiSO4·6H2O, 50 g / L NiCl2·6H2O, and 35 g / L H3BO3, with a current density of 3A / dm³. 2 The process takes 2 hours to deposit a nickel layer. The nickel-plated steel is then placed in a copper sulfate plating solution composed of 200 g / L CuSO4·5H2O and 55 g / L H2SO4, with a current density of 2 A / dm³. 2 The deposition time was 1.8 hours, resulting in a copper layer with a thickness of 180 µm (80 µm copper / 100 µm nickel).

[0065] Test results:

[0066] The friction component for the main deceleration unit of an aircraft obtained in this embodiment has a Brinell hardness of 19HB and an interfacial shear strength of 57MPa in the functional layer material.

[0067] The friction component for the main gearbox of the aircraft obtained in this embodiment, under simulated braking conditions of the main gearbox, has an average friction coefficient of 0.24, an average friction stability coefficient of 0.95, and an average wear amount per cycle of 0.0016 cm. 3 Within 80 to 100 cycles, the friction coefficient is greater than 0.22 and the stability coefficient is greater than 0.94.

[0068] Example 5

[0069] The conditions are the same as in Example 1, except that: copper powder 56% (particle size: 200-300 mesh), bronze powder 3% (particle size: 200-300 mesh), iron powder 18% (particle size: 200-300 mesh), and nickel powder 3% (particle size: 200-300 mesh).

[0070] Test results:

[0071] The friction component for the main deceleration unit of an aircraft obtained in this embodiment has a Brinell hardness of 19HB and an interfacial shear strength of 54MPa.

[0072] The friction component for the main gearbox of the aircraft obtained in this embodiment, under simulated braking conditions of the main gearbox, has an average friction coefficient of 0.24, an average friction stability coefficient of 0.94, and an average wear amount per cycle of 0.0018 cm. 3 Within 80 to 100 cycles, the friction coefficient is greater than 0.24 and the stability coefficient is greater than 0.92.

[0073] Example 6

[0074] The conditions are the same as in Example 1, except that the functional layer material composition is: 58% copper powder (particle size: 200-300 mesh), 2% bronze powder (particle size: 200-300 mesh; composed of 93.1wt% copper, 5.4wt% Sn, and 1.5wt% Zn), 16% iron powder (particle size: 200-300 mesh), 4% nickel powder (particle size: 200-300 mesh), 18% graphite (particle size: 60-100 mesh), and 2% CrFe alloy powder (particle size: 200-250 mesh).

[0075] Test results:

[0076] The resulting friction component has a Brinell hardness of 16 HB and an interfacial shear strength of 51 MPa.

[0077] The friction component for the main decelerator of the aircraft obtained in this embodiment has an average friction coefficient of 0.26, an average friction stability coefficient of 0.93, and an average wear amount per cycle of 0.0018 cm³ under simulated braking conditions of the main decelerator of the aircraft. Within 80 to 100 cycles, the friction coefficient is greater than 0.25 and the stability coefficient is greater than 0.93.

[0078] Example 7

[0079] The conditions are the same as in Example 1, except that the functional layer material is composed of 50% copper powder, 8% bronze powder, 18% iron powder, 5% nickel powder, 17% graphite powder, and 2% CrFe powder.

[0080] Test results:

[0081] The resulting friction component has a Brinell hardness of 21 HB and an interfacial shear strength of 56 MPa.

[0082] The friction component for the main decelerator of the aircraft obtained in this embodiment has an average friction coefficient of 0.28, an average friction stability coefficient of 0.92, and an average wear amount per cycle of 0.0021 cm³ under simulated braking conditions of the main decelerator of the aircraft. Within 80 to 100 cycles, the friction coefficient is greater than 0.26 and the stability coefficient is greater than 0.92.

[0083] Comparative Example 1

[0084] The conditions are the same as in Example 1, except that cast tin bronze (copper (92.7 wt%), Sn (5.9 wt%), Zn (1.4 wt%)) is used as the functional layer material of the friction component in this comparative example.

[0085] The friction component for the main deceleration unit of an aircraft obtained in this comparative example has a Brinell hardness of 87 HB and an interfacial shear strength of 68 MPa for the functional layer material.

[0086] The friction component for the main gearbox of the aircraft obtained in this comparative example, under simulated braking conditions of the main gearbox of the aircraft, has an average friction coefficient of 0.48, an average friction stability coefficient of 0.67, and an average wear amount per cycle of 0.0233 cm. 3 After 62 cycles of friction, the surface of the friction parts becomes severely worn and cannot be used.

[0087] Comparative Example 2

[0088] The conditions are the same as in Example 1, except that there is no interface layer.

[0089] Test results:

[0090] The friction component for the main deceleration unit of an aircraft obtained in this comparative example has a Brinell hardness of 18 HB and a shear strength of 21 MPa for the functional layer material.

[0091] The friction component for the main gearbox of the aircraft obtained in this comparative example, under simulated braking conditions, has an average friction coefficient of 0.21, an average friction stability coefficient of 0.91, and an average wear amount per cycle of 0.0029 cm. 3 A crack appeared at the connection between the functional layer and the alloy structural layer during 44 braking cycles.

[0092] Comparative Example 3

[0093] The conditions are the same as in Example 1, except that the interface layer is copper-plated, nickel-free, and 200µm thick.

[0094] Test results:

[0095] The friction component for a main decelerator of an aircraft obtained in this comparative example has a functional layer material with a Brinell hardness of 18 HB and an interfacial shear strength of 38 MPa.

[0096] The friction component for the main gearbox of the aircraft obtained in this comparative example, under simulated braking conditions, has an average friction coefficient of 0.23, an average friction stability coefficient of 0.89, and an average wear amount per cycle of 0.0027 cm. 3 Within 80 to 100 cycles, the friction coefficient is less than 0.20 and the stability coefficient is less than 0.74.

[0097] Comparative Example 4

[0098] The conditions are the same as in Example 1, except that the interface layer thickness is 80µm (42µm copper / 38µm nickel).

[0099] Test results:

[0100] The friction component for the main deceleration unit of an aircraft obtained in this comparative example has a Brinell hardness of 18 HB and an interfacial shear strength of 31 MPa.

[0101] The friction component for the main gearbox of the aircraft obtained in this comparative example, under simulated braking conditions, has an average friction coefficient of 0.21, an average friction stability coefficient of 0.84, and an average wear amount per cycle of 0.0022 cm. 3 Within 80 to 100 cycles, the friction coefficient is less than 0.20 and the stability coefficient is less than 0.80.

[0102] Comparative Example 5

[0103] All other conditions are the same as in Example 1, except that:

[0104] (1) Mixing of raw materials for functional layer materials: Prepare 59% copper powder (particle size: 200~300 mesh), 0% bronze powder (particle size: 200-300 mesh), 17% iron powder (particle size: 200~300 mesh), 4% nickel powder (particle size: 200-300 mesh), 18% graphite (particle size: 60~100 mesh), and 2% CrFe alloy powder (particle size: 200-250 mesh) according to the designed composition (mass percentage content); then add 5% kerosene of the total mass of the prepared powder and mix it with a roller to obtain uniform powder.

[0105] Test results:

[0106] The friction component for the main deceleration unit of an aircraft obtained in this comparative example has a Brinell hardness of 18 HB and an interfacial shear strength of 31 MPa.

[0107] The friction component for the main gearbox of the aircraft obtained in this comparative example, under simulated braking conditions, has an average friction coefficient of 0.31, an average friction stability coefficient of 0.72, and an average wear amount per cycle of 0.0038 cm. 3Within 80 to 100 cycles, the friction coefficient is greater than 0.29 and the stability coefficient is less than 0.70.

[0108] Comparative Example 6

[0109] All other conditions are the same as in Example 1, except that:

[0110] (1) Mixing of raw materials for functional layer materials: According to the designed composition (mass percentage), prepare 49% copper powder (particle size: 200~300 mesh), 10% bronze powder (particle size: 200-300 mesh), 17% iron powder (particle size: 200~300 mesh), 4% nickel powder (particle size: 200-300 mesh), 18% graphite (particle size: 60~100 mesh), and 2% CrFe alloy powder (particle size: 200-250 mesh); then add 5% kerosene of the total mass of the prepared powders and mix them in a roller to obtain uniform powder.

[0111] The friction component for the main deceleration unit of an aircraft obtained in this comparative example has a Brinell hardness of 24 HB and an interfacial shear strength of 62 MPa.

[0112] Under simulated braking conditions of the aircraft's main decelerator, the average friction coefficient is 0.28, the average friction stability coefficient is 0.84, and the average wear per cycle is 0.0034 cm. 3 Within 80 to 100 cycles, the friction coefficient is greater than 0.21 and the stability coefficient is less than 0.80.

[0113] Comparative Example 7

[0114] All other conditions are the same as in Example 1, except that:

[0115] (1) Mixing of raw materials for functional layer materials: Prepare 57% copper powder (particle size: 200~300 mesh), 2% tin powder (particle size: 200-300 mesh), 17% iron powder (particle size: 200~300 mesh), 4% nickel powder (particle size: 200-300 mesh), 18% graphite (particle size: 60~100 mesh), and 2% CrFe alloy powder (particle size: 200-250 mesh) according to the designed composition (mass percentage content); then add 5% kerosene of the total mass of the prepared powder and mix it with a roller to obtain uniform powder.

[0116] The friction component for the main deceleration unit of an aircraft obtained in this comparative example has a Brinell hardness of 23 HB and an interfacial shear strength of 44 MPa.

[0117] The obtained friction component, under simulated braking conditions of an aircraft's main decelerator, exhibits an average friction coefficient of 0.36, an average friction stability coefficient of 0.71, and an average wear amount per cycle of 0.0031 cm. 3At the 84th test, surface adhesion occurred due to heat accumulation, making it impossible to continue testing.

[0118] Comparative Example 8

[0119] Other conditions are the same as in Example 1, except that in the coating preparation process, the steel is placed in a copper sulfate plating solution composed of 200 g / L CuSO4·5H2O and 55 g / L H2SO4, with a current density of 2 A / dm³. 2 Copper layer was deposited over a period of 2 hours.

[0120] The copper-plated steel was placed in a nickel sulfate plating solution composed of 280 g / L NiSO4·6H2O, 50 g / L NiCl2·6H2O, and 35 g / L H3BO3, with a current density of 3 A / dm³. 2 The deposition time was 2.5 hours, resulting in a nickel layer (steel / 100µm copper / 100µm nickel), thus obtaining the steel alloy structural layer / copper / nickel interface layer of the friction component.

[0121] Test results:

[0122] The friction component for the main deceleration unit of an aircraft obtained in this embodiment has a Brinell hardness of 18HB and an interfacial shear strength of 34 MPa.

[0123] The friction components for the aircraft's main deceleration unit, under simulated braking conditions, exhibit an average friction coefficient of 0.22, an average friction stability coefficient of 0.86, and an average wear per cycle of 0.0031 cm. 3 Within 80 to 100 cycles, the friction coefficient is approximately 0.20, and the stability coefficient is less than 0.85.

Claims

1. A friction component for an aircraft main deceleration unit, characterized in that: The friction element has a sandwich structure, which includes a functional layer, an interface layer, and an alloy structure layer. The interface layer is attached to the alloy structure layer, and the functional layer is attached to the interface layer. The functional layer is made of copper-based friction material, and the raw material composition of the copper-based friction material, by mass percentage, consists of the following components: 50-58% pure copper powder, 2-8% bronze powder, 8-18% iron powder, 2-5% nickel powder, 16-19% graphite powder, and 1-3% CrFe powder. The interface layer is a copper / nickel plating. The alloy structure layer is a steel structure layer, and the nickel plating in the interface layer is in direct contact with the steel structure layer.

2. The friction component for an aircraft main reducer according to claim 1, characterized in that: The total thickness of the copper / nickel plating is 180~300 micrometers, preferably 195~205 micrometers, wherein the ratio of the thickness of the copper plating to the thickness of the nickel plating is 0.8~1.2:0.8~1.2, preferably 1:

1.

3. A friction component for an aircraft main deceleration unit according to claim 1, characterized in that: The raw material composition of its functional layer copper-based friction material, calculated by mass percentage, consists of the following components: 54-56% pure copper powder, 3-5% bronze powder, 16-18% iron powder, 3-5% nickel powder, 17-19% graphite powder, and 1.5-2.5% CrFe powder.

4. A friction component for an aircraft main deceleration unit according to claim 3, characterized in that: The raw material composition of its functional layer copper-based friction material, calculated by mass percentage, consists of the following components: 55% pure copper powder, 4% bronze powder, 17% iron powder, 4% nickel powder, 18% graphite powder, and 2% CrFe powder.

5. A friction component for an aircraft main reducer according to claim 1, characterized in that: The bronze powder is composed of the following components by mass percentage: copper 85-95%, Sn 4.5-8%, Zn 0.5-2%.

6. A friction component for an aircraft main deceleration unit according to claim 1, characterized in that: The particle size of pure copper powder is 200-300 mesh; the particle size of bronze powder is 200-300 mesh; the particle size of iron powder is 200-300 mesh; the particle size of nickel powder is 200-300 mesh; the particle size of graphite powder is 60-100 mesh; and the particle size of CrFe alloy powder is 150-250 mesh.

7. A method for manufacturing a friction component for an aircraft main deceleration unit, characterized in that, Includes the following steps: (1) Mixing of raw materials for functional layer materials: Copper powder, bronze powder, iron powder, nickel powder, graphite powder and CrFe powder are mixed according to the designed composition; 3-5% of kerosene is added to the mixed powder according to the total mass of the powder, and the powder is mixed by a roller to obtain uniform powder. (2) Functional layer material compression molding: The powder mixed evenly in (1) is added into the mold and cold-pressed to obtain the molded blank. The molding pressure is 10-15MPa and the holding time is 5-10s. (3) Preparation of copper / nickel plating on steel surface: copper / nickel electroplating is performed on the surface of alloy structure layer, the copper / nickel thickness ratio is 1:(1-2), the plating thickness is 100~300µm, and the copper / nickel interface layer and steel alloy structure layer of friction part are obtained. (4) Friction component assembly: The functional layer material is placed on top of the interface layer and the alloy structure layer, and the outer ring is fixed with tape; (5) Friction component sintering: The assembled friction component is placed in a pressure sintering furnace under a protective atmosphere. The sintering temperature is 780-850 ℃, the pressure is 1.5-2 MPa, and the holding time is 2-3 hours. Then, it is cooled with the furnace to obtain the friction component for the main reducer of the aircraft.

8. A method for manufacturing a friction component for an aircraft main decelerator according to claim 7, characterized in that, The method for preparing the interface layer is as follows: A surface cleaned and dried steel is placed in a nickel sulfate plating solution consisting of NiSO4.6H2O 240-300 g / L, NiCl2.6H2O 40-60 g / L, H3BO3 30-40 g / L, at a current density of 2-5 A / dm 2 , for a time of 1.5-4 h, to deposit a nickel layer; Nickel-plated steel is placed in a copper sulfate plating solution, which consists of 180-220 g / L CuSO4·5H2O and 50-60 g / L H2SO4, with a current density of 1-3 A / dm³. 2 The time is 1.5 to 4 hours, and a copper layer is deposited.

9. A method for manufacturing a friction component for an aircraft main deceleration unit according to claim 7, characterized in that: In step (2), the powder that was mixed evenly in (1) is added into the mold and cold-pressed to obtain a blank. The molding pressure is 10~15MPa and the holding time is 1-30s.

10. A method for manufacturing a friction component for an aircraft main reducer according to claim 7, characterized in that: In step (5), the sintering temperature is 815~825 ℃, the pressure is 1.9~2.1MPa, and the holding time is 145~160min.

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