Lightweight high-strength polymer-based water-lubricated gear and preparation method thereof

Abstract

According to the light-weight high-strength polymer-based water-lubricated gear and the preparation method thereof, polyether-ether-ketone serves as a base body, carbon fibers serve as a main reinforcing phase, the light-weight high-strength water-lubricated gear is a gear part with water environment adaptability, the strength, the friction and wear performance and the water environment adaptability of the light-weight high-strength water-lubricated gear are improved through material component design, and multi-dimensional performance balanced regulation and control are achieved; in the aspect of a preparation process, the gear structure and shape are precisely controlled through one-step forming of a hot mold pressing process under specific conditions, and then stress during forming is released through annealing treatment, so that the light-weight, high-strength and self-lubricating characteristics of a polymer are fully exerted, and the use requirement of a transmission part in a water environment is met. The polymer-based water-lubricated gear disclosed by the invention has outstanding environmental adaptability under a water or seawater environmental medium, is high in self strength and strong in water resistance, and is free of cracks, stripping or fracture damage after being used for a long period of time; meanwhile, the friction coefficient and the wear rate are extremely low, and the gear is particularly suitable for gear parts serving in a water environment.

Description

Technical Field

[0001] The invention relates to a light polymer-based gear, in particular to a polyetheretherketone water-lubricated gear, which is mainly used for transmission parts serving in water or underwater, and belongs to the field of materials and mechanical engineering. Background Art

[0002] Water hydraulic transmission directly uses water or seawater instead of traditional mineral oil as the working medium, which has significant advantages such as clean and pollution-free, safe and reliable, low-cost and widely available. The gear pump is the simplest and most commonly used fixed-displacement power element in the volumetric water hydraulic transmission system, and its core component is the gear friction pair. Unlike oil hydraulic pumps, the selection of gear materials in water environments needs to meet the special working conditions of water hydraulic power elements: that is, due to the low viscosity of water, it is difficult to form an effective lubricating film between the moving friction pairs in the water environment, and excessive wear will aggravate the internal leakage of the gear pump and reduce the service life of the gear pump, so there are extremely high requirements for the self-lubricating performance of the gear components.

[0003] Thermoplastic polymers represented by polyetheretherketone have the characteristics of light weight and high strength. Their application as gear materials helps to reduce the mass and moment of inertia of the system, improve power density and control accuracy, and reduce vibration and noise. For example, the gear vibration and noise evaluation method disclosed in CN119004921B uses polymer gears and steel gears to mesh with each other to form a gear pair. The gear pair in the composite transmission reducer disclosed in CN118980515A uses polyoxymethylene, polyamide or polyetheretherketone as the active gear and 20CrMnTi as the driven gear. However, when used as a gear component serving in an aqueous environment, polyetheretherketone also needs to be compositely modified to meet the comprehensive requirements of harsh design conditions and service environments for its strength, wear rate, water absorption and other properties. Although some studies have preliminarily verified that polyetheretherketone is very suitable for use as a friction pair matching material for stainless steel metal gears in an aqueous environment, there is no public report on its material design and precision molding process.

[0004] Existing gear manufacturing technology mainly uses thermosetting resin as the matrix material and continuous fiber as the reinforcement material, which is cured and formed by heating. There is a significant gap between thermosetting resin and thermoplastic polymers represented by polyetheretherketone; at the same time, most of them do not consider the influence of continuous fiber orientation and arrangement on gear performance. In addition, the existing gear material technology does not specifically describe the gear structure and shape, and lacks special designs for different tooth shapes, different specifications and service environments. For example, JP60206630A improves the gear tooth profile strength through continuous fiber winding molding, but the matrix used is still thermosetting resin. CN1050698A semi-cures the impregnated fiber belt into a toothed belt, then puts it into the mold and fills it with chopped fiber material, and then cures it into a gear. Patent US10907719B2 discloses a hybrid composite gear, which uses a toothed prepreg belt to be preformed by hot pressing, and then is formed by hot melt welding or ultrasonic welding. Patent US5059464A discloses a phenolic resin gear and its manufacturing method. The gear teeth are made of phenolic resin pre-impregnated continuous fiber cloth cut, curled into rods, and then bent into annular rings, which are then hot-pressed and machined. Patent JP4844495B2 also curls the fiber reinforcement into multi-layer rods and bends them into annular rings, which are then hot-pressed. Patent DE102017223305A1 composites a mesh continuous fiber semi-finished product with a plastic matrix into a plastic gear, but the related mesh continuous fiber arrangement structure is very complex and its application is limited. Summary of the invention

[0005] In view of this, the purpose of the present invention is to disclose a polymer gear with polyetheretherketone as the matrix and carbon fiber as the main reinforcement phase, which has the characteristics of light weight and high strength. The strength, friction and wear performance and adaptability to water environment are improved through material component design, and multi-dimensional performance balance regulation is achieved; in terms of preparation technology, the gear structure and shape are precisely regulated through one-step molding through a hot molding process under specific conditions, so as to give full play to the lightweight wear resistance and self-lubricating characteristics of the polymer and meet the use requirements of transmission components in water environment.

[0006] 1. Water-lubricated gears and their preparation like Figure 1 As shown, a light-weight, high-strength polymer-based water-lubricated gear is made of a polyetheretherketone composite material as a base material and is prepared through hot molding and annealing processes; The gear is a straight tooth type, with a thickness of 5-15 mm, a number of teeth of 9-18, an inner diameter of 1-4 mm, a tooth root radius of 5-8 mm, a full tooth height of 3-6 mm, and a tooth pitch of 2.0-5.0 mm; The polyetheretherketone composite material comprises the following raw materials by weight: 88-92 parts of polyetheretherketone resin, 8-12 parts of carbon fiber, and 0.2-1.0 parts of modified filler.

[0007] The bulk density of the polyetheretherketone resin is 0.25-0.60 g / cm 3 , melt mass flow rate 2.5~15cm 3 / 10min.

[0008] The carbon fiber is polyacrylonitrile-based carbon fiber with a diameter of 6.5-8.9 μm and an aspect ratio of 5-100.

[0009] The modified filler is one or more of polyetherketone, polyetherketoneetherketoneketone, polyimide, and polytetrafluoroethylene, and has a size of 20 to 80 μm.

[0010] The preparation method of the lightweight high-strength polymer-based water-lubricated gear is as follows: First, the polyetheretherketone resin, carbon fiber and modified filler are mixed evenly and then spread in a toothed steel mold. Subsequently, they are sintered at a temperature of 360~380℃ and a pressure of 2~5MPa for 30~100min, cooled and demolded, and after simple trimming, annealed at 120~250℃ for 15~80min to obtain a polymer-based water-lubricated gear.

[0011] 2. Performance of water-lubricated gears 1. Mechanical properties The PEEK composite material blanks made by the same process were machined into the size specified by the national standard and tested for mechanical properties on a universal testing machine. The tensile strength specimen was a dumbbell shape of 80 mm × 10 mm × 4 mm. The test standard was GB / T 1040.2-2022 and the tensile rate was 1 mm / min. The test showed that the tensile strength of the water-lubricated gear material was 95~120 MPa.

[0012] 2. Friction and wear performance The test method is as follows: According to ASTM G99-05, the obtained polyetheretherketone composite material molded product is processed into a block sample with a size of 19mm×12mm×12mm, matched with a 316 stainless steel ring, and tested in an MRH-3 high-speed ring block friction and wear tester; the test contact load is 200N, the linear speed is 0.5m / s, and the running time is 30min; the friction coefficient is automatically recorded and output by the tester, and the wear rate is calculated by the mass loss before and after the sample is worn. The test results show that the friction coefficient of the water-lubricated gear material is 0.04~0.06, and the wear rate is (1.1~2.9)×10 -7 mm 3 / Nm.

[0013] 3. Water absorption The polyetheretherketone composite material sample was machined into a Φ25mm×25mm cylinder, and the test method was based on GB / T1034-2008 "Determination of water absorption of plastics". The medium was deionized water. The test showed that the 24h water absorption rate of water-lubricated gear materials was 0.01%~0.03%.

[0014] In summary, the polymer-based water-lubricated gear of the present invention uses polyetheretherketone as the matrix and carbon fiber as the main reinforcement phase. It is a light, high-strength, and water-adaptable gear component. Its strength, friction and wear performance, and water-adaptability are improved through material component design, achieving multi-dimensional performance balance regulation; in terms of preparation technology, it is formed in one step through a hot molding process under specific conditions, and precise regulation of the gear structure and shape is achieved, thereby giving full play to the lightweight, wear-resistant and self-lubricating properties of the polymer, and meeting the use requirements of transmission components in water environments. The polymer-based water-lubricated gear described in the present invention has outstanding environmental adaptability in water or seawater environment media, has high self-strength and strong water resistance, and has no cracks, peeling or fracture damage after long-term service; at the same time, the friction coefficient and wear rate are extremely low, which is particularly suitable for gear components serving in water environments, and can also be promoted and applied to various types of transmission components serving in other media. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the planar structure of the lightweight and high-strength polymer-based water-lubricated gear of the present invention.

[0016] Figure 2 This is a schematic diagram of the assembly of the water-lubricated gear and the metal shaft according to Example 1 of the present invention. DETAILED DESCRIPTION

[0017] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments.

[0018] Example 1 92g of polyetheretherketone resin (bulk density 0.25g / cm 3 , melt mass flow rate 2.5cm 3 / 10min), 7g carbon fiber (diameter 7.2μm, aspect ratio 100) and 1g polytetrafluoroethylene (20μm) were mixed evenly, and 0.3g was spread in the toothed steel mold, and then sintered at a temperature of 365℃ and a pressure of 2MPa for 45min, and then trimmed after cooling and demoulding; then annealed at a temperature of 120℃ for 15min, and a water-lubricated gear with a thickness of 5mm, 9 teeth, an inner diameter of 2mm, a root radius of 5mm, a full tooth height of 3mm, and a tooth pitch of 4.5mm was obtained. Then, it can be put into use after being installed on a metal rod. The actual picture is as attached Figure 2 shown.

[0019] After testing, the tensile strength of the water-lubricated gear material obtained in Example 1 is 95 MPa, the friction coefficient is 0.04, and the wear rate is 1.1×10 -7 mm 3 / Nm, 24h water absorption rate is 0.01%.

[0020] Example 2 45.0 g of polyetheretherketone resin (bulk density 0.50 g / cm 3 , melt mass flow rate 10cm 3 / 10min), 4.6g carbon fiber (diameter 7.4μm, aspect ratio 10) and 0.4g polyether ketone (60μm) were mixed evenly, and 1.3g was spread in the toothed steel mold, and then sintered at 370℃ and 3MPa for 80min, and then trimmed after cooling and demoulding; then annealed at 150℃ for 30min, and a water-lubricated gear with a thickness of 5mm, 12 teeth, an inner diameter of 3mm, a root radius of 6mm, a full tooth height of 5mm, and a pitch of 4.4mm was obtained. Then, it can be put into use after being installed on a metal rod.

[0021] After testing, the tensile strength of the water-lubricated gear material obtained in Example 2 is 110 MPa, the friction coefficient is 0.06, and the wear rate is 1.7×10 -7 mm 3 / Nm, 24h water absorption rate is 0.02%.

[0022] Example 3 176.0 g of polyetheretherketone resin (bulk density 0.60 g / cm 3 , melt mass flow rate 15cm 3 / 10min), 23g carbon fiber (diameter 7.9μm, aspect ratio 50) and 1g polyether ketone ether ketone ketone (50μm) were mixed evenly, and 1.0g was spread in a toothed steel mold, and then sintered at a temperature of 375℃ and a pressure of 2.5MPa for 100min, and then trimmed after cooling and demoulding; then annealed at a temperature of 150℃ for 30min, and a water-lubricated gear with a thickness of 5mm, 18 teeth, an inner diameter of 2mm, a root radius of 8mm, a full tooth height of 3mm, and a tooth pitch of 3.3mm was obtained. Then, it can be put into use after being installed on a metal rod.

[0023] After testing, the tensile strength of the water-lubricated gear material obtained in Example 2 is 120 MPa, the friction coefficient is 0.06, and the wear rate is 2.9×10 -7 mm 3 / Nm, 24h water absorption rate is 0.03%.

Claims

1. A lightweight, high-strength polymer-based hydrating gear, characterized in that: The hydrating gear is made of polyetheretherketone composite material as the base material and is prepared after hot molding and annealing treatment; The gear parameters are as follows: spur gear, thickness 5~15mm, number of teeth 9~18, inner diameter 1~4mm, root circle radius 5~8mm, full tooth height 3~6mm, pitch 2.0~5.0mm; The polyetheretherketone composite material comprises the following raw materials by weight: 88-92 parts of polyetheretherketone resin, 8-12 parts of carbon fiber, and 0.2-1.0 parts of modified filler.

2. A lightweight and high-strength polymer-based hydrating gear as claimed in claim 1, characterized in that: The bulk density of the polyetheretherketone resin is 0.25-0.60 g / cm 3 , melt mass flow rate 2.5~15cm 3 / 10min.

3. A lightweight and high-strength polymer-based hydrating gear as claimed in claim 1, characterized in that: The carbon fiber is polyacrylonitrile-based carbon fiber with a diameter of 6.5-8.9 μm and an aspect ratio of 5-100.

4. A lightweight and high-strength polymer-based hydrating gear as claimed in claim 1, characterized in that: The modified filler is one or more of polyetherketone, polyetherketoneetherketoneketone, polyimide, and polytetrafluoroethylene, and has a size of 20 to 80 μm.

5. A method for preparing a lightweight and high-strength polymer-based hydrating gear as claimed in claim 1, characterized in that: First, the polyetheretherketone resin, carbon fiber and modified filler are mixed evenly and then spread in a toothed steel mold. Subsequently, they are sintered at a temperature of 360~380℃ and a pressure of 2~5MPa for 30~100min, cooled and demolded, and after simple trimming, annealed at 120~250℃ for 15~80min to obtain a polymer-based water-lubricated gear.

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