Preparation method of light-weight corrosion-resistant non-magnetic titanium alloy bearing and product

Abstract

The invention discloses a preparation method and a product of a light-weight corrosion-resistant non-magnetic titanium alloy bearing, and relates to the technical field of bearing manufacturing, the light-weight corrosion-resistant non-magnetic titanium alloy bearing comprises an outer ring, an inner ring, a raceway, rolling bodies and a retainer, the annular raceway is formed between the outer circumferential surface of the inner ring and the inner circumferential surface of the outer ring, and the rolling bodies are uniformly distributed in the raceway through the retainer; the inner ring and the outer ring are made of a light-weight corrosion-resistant non-magnetic titanium alloy material, the rolling body is made of a non-magnetic ceramic material, and the retainer is made of a corrosion-resistant non-metal material; the inner ring, the outer ring, the rolling body and the retainer are all subjected to grinding and ultra-finishing polishing treatment, and the surface roughness Ra is smaller than or equal to 0.2 micrometer. By optimizing material selection, a precision machining process and assembly control, the technical purposes of light weight, high corrosion resistance, no magnetism and high precision are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of bearing manufacturing, specifically a preparation method and product of lightweight, corrosion-resistant, non-magnetic titanium alloy bearings. Background Art

[0002] As core components of mechanical transmission systems, bearings are widely used in aerospace, marine engineering, high-end equipment manufacturing, medical imaging equipment, and other fields. As application scenarios become more complex, higher requirements are placed on the comprehensive performance of bearings. For example, the aerospace field requires lightweight bearings to reduce the weight of aircraft; marine engineering equipment requires bearings to be resistant to seawater corrosion to extend their service life; and medical MRI (magnetic resonance imaging) equipment requires non-magnetic bearings to avoid interference with the magnetic field.

[0003] However, the patents in the prior art have the following disadvantages:

[0004] (1) Traditional metal bearings (such as steel bearings): Metal bearings represented by GCr15 and stainless steel have high strength but high density (about 7.8g / cm 3 ), which cannot meet the demand for lightweighting; and stainless steel is prone to pitting corrosion in seawater environments (pitting potential is usually less than 600mV vs SCE), and its corrosion resistance is insufficient; in addition, steel materials themselves are ferromagnetic and will be affected by magnetization in strong magnetic fields, limiting their application in non-magnetic scenarios.

[0005] (2) Ceramic bearings: Although ceramic bearings such as silicon nitride (Si3N4) and zirconium oxide (ZrO2) have a low density (about 3.2g / cm 3 ) has good corrosion resistance, but its hardness is high and processing is difficult. In addition, ceramic materials are brittle (fracture toughness is usually less than 6MPa·m1 / 2) and are prone to failure under impact loads. In addition, the inner and outer rings and rolling elements of ceramic bearings are all made of ceramic materials. During assembly, stress cracking is easily caused by differences in thermal expansion coefficients, which limits reliability.

[0006] (3) Composite bearings: Although some bearings made of polymer (such as polyimide) or carbon fiber reinforced composite materials have the potential to be lightweight and corrosion-resistant, they have low load-bearing capacity (tensile strength is generally less than 800 MPa) and poor wear resistance (surface roughness is difficult to control below 0.2 μm). They are only suitable for low-load and low-speed scenarios and cannot replace metal bearings in medium and high-load applications.

[0007] Invention content

[0008] The purpose of the new invention is to provide a preparation method and product of lightweight, corrosion-resistant, non-magnetic titanium alloy bearings. By optimizing material selection, precision processing technology and assembly control, the technical goals of lightweight, strong corrosion resistance, non-magnetism and high precision are achieved.

[0009] To achieve the above objectives, the present invention is implemented through the following technical solutions: a preparation method and product of a lightweight, corrosion-resistant, non-magnetic titanium alloy bearing, including an outer ring, an inner ring, a raceway, rolling elements, and a retaining frame. An annular raceway is formed between the outer circumferential surface of the inner ring and the inner circumferential surface of the outer ring, and the rolling elements are evenly distributed in the raceway through the retaining frame; the inner ring and outer ring are made of lightweight, corrosion-resistant, non-magnetic titanium alloy material, the rolling elements are non-magnetic ceramic material, and the retaining frame is corrosion-resistant non-metallic material; the inner ring, outer ring, rolling elements and retaining frame are all ground and ultra-polished, and the surface roughness Ra≤0.2μm.

[0010] Furthermore, the titanium alloy material of the inner ring and the outer ring is Ti-6Al-4V ELI titanium alloy grade, and its density is ≤4.43g / cm 3 , tensile strength ≥ 950MPa, elongation ≥ 15%, and strengthened by solution aging treatment, the corrosion resistance meets the pitting potential ≥ 800mV vs SCE in seawater environment in ASTM G48 standard.

[0011] Furthermore, the outer circumferential surface of the inner ring and the inner circumferential surface of the outer ring are respectively rough turned and fine turned, and then ground and ultra-finished, wherein: after rough turning, the outer diameter size tolerance is controlled within ±0.1mm, the inner diameter size tolerance is controlled within ±0.08mm, and the surface roughness of the groove and the plane Ra≤3.2μm; after fine turning, the outer diameter size tolerance is controlled within ±0.02mm, the inner diameter size tolerance is controlled within ±0.015mm, and the surface roughness of the groove and the plane Ra≤0.8μm; after grinding and ultra-finishing, the surface roughness of the outer diameter, inner diameter, groove and plane Ra≤0.2μm, and the shape accuracy roundness and flatness ≤0.002mm.

[0012] Furthermore, all machining dimensions of the inner and outer rings, including outer diameter D1, inner diameter d1, groove diameter D2, and plane height h1, are fully inspected by a three-coordinate measuring machine (CMM), with an inspection accuracy of ≤0.5μm, and meet the tolerance requirements of the design drawings: outer diameter tolerance ±0.025mm, inner diameter tolerance ±0.02mm, groove diameter tolerance ±0.015mm, and plane height tolerance ±0.01mm.

[0013] Furthermore, the inner and outer rings were cleaned with a mixed solvent of anhydrous ethanol and acetone in a volume ratio of 1:1 in an ultrasonic cleaning machine for 15 minutes and then dried with compressed air. The residual contaminants, oil stains and metal chips on the surface were ≤0.1 mg / cm 2 .

[0014] Furthermore, the assembly process is as follows: pre-installing the retaining cage into the retaining cage groove of the outer ring, sequentially installing the rolling bodies into the retaining cage pockets by a robot, and finally pressing the inner ring axially into the gap between the outer ring and the rolling bodies; after assembly, the radial clearance between the inner ring and the outer ring is controlled within 0.03 to 0.05 mm, the axial clearance is controlled within 0.02 to 0.04 mm, and the vibration value of the assembly is detected by a vibration detector to be ≤10 μm at 1000 rpm.

[0015] Furthermore, the rolling element is a silicon nitride Si3N4 ceramic ball with a density of ≤3.2g / cm 3 , hardness HV ≥ 1500, fracture toughness KIC ≥ 7MPa·m1 / 2, and the surface roughness Ra ≤ 0.1μm after polishing, the contact angle with the titanium alloy inner and outer rings is 45°~60°, and the rolling friction coefficient ≤ 0.003.

[0016] Furthermore, the retainer is made of polyimide PI composite material, with a thermal deformation temperature of ≥260°C and a linear expansion coefficient of ≤2×10 -6 / ℃, the friction coefficient with the titanium alloy inner and outer rings is ≤0.15 dry friction, and it is processed by die pressing process, with a pocket size tolerance of ±0.005mm to ensure that the rolling elements are not stuck.

[0017] Furthermore, the assembly surfaces of the inner ring and the outer ring, i.e., the end faces of the inner ring and the outer ring, are ground and ultra-polished to form a micron-level smooth surface Ra≤0.1μm. During assembly, the axial pressing amount is controlled by a laser rangefinder to avoid clearance deviation caused by end face extrusion deformation.

[0018] Furthermore, the outer surfaces of the inner ring and outer ring can be selectively coated with a diamond-like carbon DLC film with a thickness of 5 to 10 μm and a hardness of HV ≥ 20 GPa, further reducing the surface friction coefficient to ≤ 0.002 and improving the salt spray corrosion resistance. The neutral salt spray test is ≥ 1000h without rust.

[0019] The present invention provides a novel method for preparing lightweight, corrosion-resistant, non-magnetic titanium alloy bearings and products thereof, which have the following beneficial effects:

[0020] 1. Balance between lightness and high strength: Inner and outer rings are made of Ti-6Al-4V ELI titanium alloy, with a density of ≤4.43g / cm 3 (much lower than the 7.8g / cm of traditional steel bearings 3 It also has excellent mechanical properties with a tensile strength of ≥950MPa and an elongation of ≥15%. It not only meets the demand for lightweighting but also can withstand high-load conditions. It is suitable for scenes that are sensitive to weight and have high loads, such as aerospace, precision instruments, etc.

[0021] 2. Excellent corrosion resistance: The titanium alloy material is strengthened through solid solution aging treatment. Its pitting potential in seawater environment (ASTM G48 standard) is ≥800mV (vs SCE), which is much higher than that of ordinary steel (usually <500mV). Combined with the optional diamond-like carbon (DLC) film (neutral salt spray resistance ≥1000h without rust) coated on the outer surface, it significantly improves reliability in harsh environments such as humidity, salt spray, and chemical corrosion, and extends service life.

[0022] 3. Non-magnetic characteristics make it suitable for special scenarios: Titanium alloy itself is a non-ferromagnetic material. Combined with non-magnetic ceramic rolling elements (such as silicon nitride) and non-metallic retaining frames (polyimide), the overall structure is non-magnetic, avoiding the electromagnetic interference problem caused by magnetism in traditional steel bearings. It is suitable for fields that are sensitive to magnetic fields, such as precision instruments, medical equipment, and nuclear magnetic resonance equipment.

[0023] 4. High-precision processing ensures stable performance: The inner and outer rings undergo multiple processes of "rough turning → fine turning → grinding and ultra-fine polishing". The surface roughness is gradually reduced from Ra ≤ 3.2μm (rough turning) to Ra ≤ 0.2μm (polishing), and the shape accuracy (roundness, flatness) is ≤ 0.002mm. All processed dimensions (outer diameter, inner diameter, groove, plane) are fully inspected by a three-dimensional coordinate measuring machine (CMM) (accuracy ≤ 0.5μm), ensuring the matching accuracy of the inner and outer ring raceways and rolling elements, reducing friction loss and lowering operating noise.

[0024] 5. Low friction and high wear resistance: Silicon nitride ceramic rolling element (density ≤3.2g / cm 3 The contact angle (45°~60°) and rolling friction coefficient (≤0.003) of the ceramic rolling element (HV≥1500) and the titanium alloy raceway are reasonably designed, and the ultra-smooth surface (assembly surface) with a surface Ra≤0.1μm significantly reduces the rolling friction resistance and reduces energy loss. At the same time, the high fracture toughness (KIC≥7MPa·m1 / 2) of the ceramic rolling element and the low friction coefficient (≤0.15 dry friction) of the polyimide cage effectively inhibit wear and extend the service life of the bearing.

[0025] 6. Precision assembly ensures operational reliability: The assembly process of "pre-installed cage → robot-mounted rolling elements → axial pressing of the inner ring" is adopted, and the press-in amount is controlled by a laser rangefinder. The radial clearance (0.03-0.05mm) and axial clearance (0.02-0.04mm) are precisely controlled to avoid clearance deviation caused by end face extrusion deformation; the vibration value after assembly is ≤10μm (at 1000rpm), ensuring the smoothness and stability of the bearing operation and reducing vibration noise.

[0026] 7. Cleanliness control to prevent potential failure: The inner and outer rings are ultrasonically cleaned with a mixed solvent of anhydrous ethanol and acetone (1:1) for 15 minutes, and the residual pollutants (oil stains, metal chips) on the surface are ≤0.1mg / cm 2 , which avoids the abrasive wear of the raceways and rolling elements caused by pollutants during operation, reduces the risk of early failure and improves the reliability of the bearing.

[0027] 8. Multifunctional scalability: The outer surface can be optionally coated with a DLC film (thickness 5-10μm, hardness HV ≥ 20GPa) to further reduce the friction coefficient (≤0.002) and improve salt spray resistance. The surface properties can be flexibly adjusted according to specific working conditions, expanding the product's application scenarios (such as extreme corrosive environments or high-precision transmission systems). BRIEF DESCRIPTION OF THE DRAWINGS

[0028] To more clearly illustrate the novel embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. Obviously, the drawings described below are merely exemplary, and those skilled in the art can, without inventive effort, derive other implementation drawings based on the provided drawings.

[0029] Figure 1 This is a schematic diagram of the new overall structure of the present invention;

[0030] Figure 2 It is a plan view of the novel overall structure of the present invention;

[0031] Figure 3 It is a cross-sectional schematic diagram of the novel overall structure of the present invention. DETAILED DESCRIPTION

[0032] Exemplary embodiments will be described in detail herein, examples of which are illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present disclosure. Rather, they are merely examples of devices consistent with certain aspects of the present disclosure, as detailed in the appended claims.

[0033] The following will be combined with the accompanying drawings of the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0034] Example 1: Rough turning and preliminary dimensional control of titanium alloy inner and outer rings

[0035] Ti-6Al-4V ELI titanium alloy rod (density 4.43g / cm 3 , tensile strength 960MPa), rough turning of the inner circumference of outer ring 1 and inner ring 2 was performed using a five-axis CNC lathe (DMG MORI CMX 600). The machining parameters were: cutting speed Vc = 85m / min, feed f = 0.25mm / r, and depth of cut ap = 1.8mm. A carbide end mill (4 flutes, 10° rake angle) was used for the groove and flat surfaces. The spindle speed was adjusted to 600rpm, ensuring a groove radius R = 15mm (designed value). After rough turning, the outer diameter tolerance of the outer ring was controlled to ±0.1mm (measured value: Φ150.05±0.1mm), and the inner diameter tolerance was ±0.08mm (measured value: Φ100.03±0.08mm). The surface roughness of the groove and flat surfaces was Ra ≤ 3.2μm (profilometer measurement, Ra = 2.9μm).

[0036] Example 2: Precision turning and precision dimension forming of titanium alloy inner and outer rings

[0037] After rough turning, the inner and outer rings were subjected to finish turning using a high-precision CNC lathe (OKUMA MU-6300V) equipped with CBN tools (brand: BN-S20). The finish turning parameters for the inner and outer surfaces of the outer and inner rings were: cutting speed Vc = 180 m / min, feed f = 0.08 mm / r, and depth of cut ap = 0.4 mm. During groove machining, circular interpolation (G03) was used to ensure groove arc consistency. After finish turning, the outer ring outer diameter tolerance was controlled to ±0.02 mm (measured value: Φ150.00 ± 0.02 mm), and the inner diameter tolerance was ±0.015 mm (measured value: Φ100.00 ± 0.015 mm). The surface roughness of the grooves and flat surfaces was Ra ≤ 0.8 μm (profilometer measurement, Ra = 0.7 μm). Ten pieces were randomly inspected using a three-dimensional coordinate measuring machine (CMM, Hexagon GLOBAL E). The outer diameter tolerance met the requirement of ±0.025mm (the maximum measured deviation was +0.02mm), and the inner diameter tolerance met the requirement of ±0.02mm (the maximum measured deviation was -0.015mm).

[0038] Example 3: Grinding, ultra-finishing and full-size inspection of titanium alloy inner and outer rings

[0039] After precision turning, the inner and outer rings undergo ultra-fine grinding and polishing using a Qingdao Precision MP-300 magnetic grinder with cerium oxide abrasive (1 μm particle size). Grinding parameters include a grinding pressure of 0.15 MPa, a spindle speed of 1000 rpm, and a machining time of 40 minutes. After polishing, the surface roughness of the outer ring's outer diameter, inner diameter, groove, and flat surfaces is Ra ≤ 0.2 μm (tested with a stylus roughness meter, Ra = 0.18 μm), and the form accuracy (roundness and flatness) is ≤ 0.002 mm (tested with a three-dimensional coordinate measuring machine, roundness 0.0016 mm, flatness 0.0012 mm). Full-dimensional inspection then proceeds: 100% inspection of the outer diameter (D1), inner diameter (d1), groove diameter (D2), and flatness height (h1) of each inner and outer ring is performed using a CMM (testing accuracy ≤ 0.5 μm). The results show that the outer diameter tolerance is ±0.025mm (measured range Φ149.98~Φ150.02mm), the inner diameter tolerance is ±0.02mm (measured range Φ99.98~Φ100.02mm), the channel diameter tolerance is ±0.015mm (measured range Φ148.00~Φ148.03mm), and the plane height tolerance is ±0.01mm (measured range 19.99~20.01mm).

[0040] The electrical components appearing in this article are all connected to an external main controller and 220V AC power, and the main controller can be a conventional known device that controls a computer, etc. The specific implementation method of this disclosure omits the detailed description of known functions and known components. To ensure the compatibility of the equipment, the operating methods used are consistent with the parameters of marketed equipment.

[0041] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a lightweight, corrosion-resistant, non-magnetic titanium alloy bearing and a product thereof, comprising an outer ring (1), an inner ring (2), a raceway (3), a rolling element (4), and a cage (5), characterized in that: An annular raceway (3) is formed between the outer circumferential surface of the inner ring (2) and the inner circumferential surface of the outer ring (1), and the rolling elements (4) are evenly distributed in the raceway (3) through the retaining frame (5); the inner ring (2) and the outer ring (1) are made of a lightweight, corrosion-resistant, non-magnetic titanium alloy material, the rolling elements (4) are made of a non-magnetic ceramic material, and the retaining frame (5) is made of a corrosion-resistant non-metallic material; the inner ring (2), the outer ring (1), the rolling elements (4) and the retaining frame (5) are all ground and ultra-finished, and the surface roughness Ra is less than or equal to 0.2 μm.

2. The preparation method and product of the lightweight, corrosion-resistant, non-magnetic titanium alloy bearing according to claim 1 are characterized by: The titanium alloy material of the inner ring (2) and the outer ring (1) is Ti-6Al-4V ELI (titanium alloy grade), and its density is ≤4.43g / cm 3 , tensile strength ≥ 950MPa, elongation ≥ 15%, and strengthened by solid solution aging treatment, the corrosion resistance meets the pitting potential ≥ 800mV (vs SCE) in seawater environment in the ASTM G48 standard.

3. The method for preparing a lightweight, corrosion-resistant, non-magnetic titanium alloy bearing and the product according to claim 1 are characterized by: The outer circumference of the inner ring (2) and the inner circumference of the outer ring (1) are respectively subjected to rough turning and fine turning, and then subjected to grinding and super-finishing polishing, wherein: after rough turning, the outer diameter dimension tolerance is controlled within ±0.1mm, the inner diameter dimension tolerance is controlled within ±0.08mm, and the surface roughness of the groove and the plane Ra is ≤3.2μm; after fine turning, the outer diameter dimension tolerance is controlled within ±0.02mm, the inner diameter dimension tolerance is controlled within ±0.015mm, and the surface roughness of the groove and the plane Ra is ≤0.8μm; after grinding and super-finishing polishing, the surface roughness of the outer diameter, inner diameter, groove and plane Ra is ≤0.2μm, and the shape accuracy (roundness, flatness) is ≤0.002mm.

4. The method for preparing a lightweight, corrosion-resistant, non-magnetic titanium alloy bearing and the product according to claim 1 are characterized by: All machining dimensions (outer diameter D1, inner diameter d1, groove diameter D2, plane height h1) of the inner ring (2) and the outer ring (1) are fully inspected by a three-coordinate measuring machine (CMM), with an inspection accuracy of ≤0.5 μm, and meet the tolerance requirements of the design drawings (outer diameter tolerance ±0.025 mm, inner diameter tolerance ±0.02 mm, groove diameter tolerance ±0.015 mm, plane height tolerance ±0.01 mm).

5. The method for preparing a lightweight, corrosion-resistant, non-magnetic titanium alloy bearing and the product according to claim 1 are characterized by: The inner ring (2) and the outer ring (1) are cleaned with a mixed solvent of anhydrous ethanol and acetone (volume ratio 1:1) in an ultrasonic cleaning machine for 15 minutes, and then blown dry with compressed air. The content of residual pollutants (oil stains, metal chips) on the surface is ≤0.1mg / cm 2 .

6. The method for preparing a lightweight, corrosion-resistant, non-magnetic titanium alloy bearing and the product according to claim 1 are characterized by: The assembly process is as follows: pre-installing the retaining frame (5) into the retaining frame groove of the outer ring (1), sequentially installing the rolling elements (4) into the pockets of the retaining frame (5) by a manipulator, and finally pressing the inner ring (2) into the gap between the outer ring (1) and the rolling elements (4) along the axial direction; after assembly, the radial clearance between the inner ring (2) and the outer ring (1) is controlled within 0.03 to 0.05 mm, and the axial clearance is controlled within 0.02 to 0.04 mm, and the vibration value of the assembly is detected by a vibration detector to be ≤10 μm (at 1000 rpm).

7. The method for preparing a lightweight, corrosion-resistant, non-magnetic titanium alloy bearing and the product according to claim 1 are characterized by: The rolling body (4) is a silicon nitride (Si3N4) ceramic ball with a density of ≤3.2g / cm 3 , hardness HV ≥ 1500, fracture toughness KIC ≥ 7MPa·m 1 / 2 The surface roughness after polishing is Ra≤0.1μm, the contact angle with the titanium alloy inner and outer rings (1, 2) is 45°~60°, and the rolling friction coefficient is ≤0.

003.

8. The preparation method and product of the lightweight, corrosion-resistant, non-magnetic titanium alloy bearing according to claim 1, characterized in that The retainer (5) is a polyimide (PI) composite material with a thermal deformation temperature of ≥260°C and a linear expansion coefficient of ≤2×10 -6 / ℃, the friction coefficient with the titanium alloy inner and outer rings (1, 2) is ≤0.15 (dry friction), and it is processed by a die-forming process, with a pocket size tolerance of ±0.005mm, ensuring that the rolling element (4) has no sticking.

9. The preparation method and product of the lightweight, corrosion-resistant, non-magnetic titanium alloy bearing according to claim 1, characterized in that The assembly surfaces of the inner ring (2) and the outer ring (1) (i.e., the end faces of the inner ring (2) and the outer ring (1)) are ground and ultra-polished to form micron-level smooth surfaces (Ra≤0.1μm). During assembly, the axial pressing amount is controlled by a laser rangefinder to avoid clearance deviation caused by end face extrusion deformation.

10. The preparation method and product of the lightweight, corrosion-resistant, non-magnetic titanium alloy bearing according to claim 1, characterized in that The outer surfaces of the inner ring (2) and the outer ring (1) can be selectively coated with a diamond-like carbon (DLC) film with a thickness of 5 to 10 μm and a hardness HV ≥ 20 GPa, further reducing the surface friction coefficient (≤ 0.002) and improving the salt spray corrosion resistance (neutral salt spray test ≥ 1000h without rust).

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