阅读说明：本技术 钛合金制滑动轴承 (Sliding bearing made of titanium alloy ) 是由 坛孟 于 2020-03-10 设计创作，主要内容包括：一种钛合金制的球面滑动轴承(A),在α+β型或者α型的钛合金制的内轮(1)的外周具有凸型球面的滑动面(2),外轮(4)介由润滑性衬套(3)与该滑动面(2)滑动接触；在滑动面(2)包含初生α晶粒和次生α晶粒,滑动面(2)的氧浓度为0.8质量％以上,硬度为550Hv以上,设置有随着距滑动面(2)表面的深度、氧浓度连续地降低的氧扩散层(5)。(A spherical sliding bearing (A) made of a titanium alloy, having a sliding surface (2) of a convex spherical surface on the outer periphery of an inner ring (1) made of an alpha + beta type or an alpha type titanium alloy, wherein an outer ring (4) is in sliding contact with the sliding surface (2) via a lubricating bush (3); the sliding surface (2) contains primary alpha crystal grains and secondary alpha crystal grains, the oxygen concentration of the sliding surface (2) is more than 0.8 mass%, the hardness is more than 550Hv, and an oxygen diffusion layer (5) with the oxygen concentration continuously decreasing with the depth from the surface of the sliding surface (2) is arranged.)

1. A sliding bearing made of a titanium alloy, comprising a sliding surface formed of an alpha + beta type or alpha type titanium alloy, wherein the sliding surface comprises primary alpha crystal grains and secondary alpha crystal grains, and is provided with an oxygen diffusion layer in which the oxygen concentration decreases continuously with the depth from the surface of the sliding surface, the surface is dissolved in oxygen at an oxygen concentration of 0.8 mass% or more, and the hardness of the surface is 550Hv or more.

2. The titanium alloy sliding bearing according to claim 1, wherein the titanium alloy is a Ti-6Al-4V titanium alloy.

3. The titanium alloy sliding bearing according to claim 1 or 2, wherein the surface of the sliding surface is composed of crystal grains having an average grain diameter of 15 μm or less, and the average grain diameter of 15 μm or less is 15 μm or less when a difference in crystal orientation of 15 ° or more is regarded as a grain boundary in an observation image measured by EBSD, areas are added in descending order from aggregated crystal grains having a large grain area over the entire observation image, and an average value of the crystal grain diameters of crystal grains reaching 70% of the total grain area in the observation image area is obtained.

4. The titanium alloy sliding bearing according to any one of claims 1 to 3, wherein the sliding bearing is a spherical sliding bearing, and the inner ring and the outer ring are in sliding contact with each other via a lubricating bush.

5. The titanium alloy sliding bearing according to claim 4, wherein the lubricating bush is a bush formed of a molded body of resin or woven fabric.

6. The titanium alloy sliding bearing according to claim 5, wherein the molded resin is a molded resin of 1 or more selected from the group consisting of polytetrafluoroethylene, polyamide, polyimide, and polyphenylene sulfide.

7. The titanium alloy sliding bearing according to claim 5, wherein the woven fabric is a woven fabric composed of 1 or more types of fibers selected from the group consisting of polytetrafluoroethylene fibers, aromatic polyamide fibers, glass fibers, and polyester fibers.

8. A titanium alloy sliding bearing for aerospace equipment, comprising the titanium alloy sliding bearing according to any one of claims 1 to 7.

Technical Field

The present invention relates to a sliding bearing, and more particularly to a sliding bearing made of a titanium alloy which can be used in the technical fields of aerospace and the like where weight reduction and durability are required.

Background

In general, a machine used for a satellite, a rocket, or the like is required to be as lightweight as possible in order to reduce fuel consumption during transportation.

Titanium alloys are known as mechanical components that can be made lightweight effectively, instead of general mechanical components such as steel.

Titanium alloys are lightweight and excellent in corrosion resistance and weight-specific strength, but have a disadvantage of low wear resistance due to lower hardness than steel.

As a method for improving the hardness of a titanium alloy, a treatment method is known in which a member is held at a heating temperature for a predetermined time in a mixed atmosphere gas mainly containing nitrogen and a small amount of oxygen, and mainly nitrogen and oxygen are dissolved in a solid solution on the surface of the member, thereby improving the hardness of the titanium alloy used for a decorative article (patent document 1).

Further, a spherical sliding bearing having a hardened surface obtained by vapor deposition of titanium nitride (TiN) by a physical vapor deposition method (PVD) on at least one of an inner ring and an outer ring of a spherical sliding bearing using a titanium alloy is known (patent document 2).

Documents of the prior art

Patent document

Patent document 1: international publication No. 97/36018

Patent document 2: japanese patent laid-open No. 2007 and 255712

Disclosure of Invention

However, the surface modification method in which nitrogen and a small amount of oxygen are dissolved in a solid solution has a problem that the toughness is low and cannot be improved although the hardness is improved.

That is, a hardened layer in which 0.6 to 8.0 wt% of nitrogen and 0.5 to 14.0 wt% of oxygen are dissolved in a solid solution on the surface of a titanium alloy increases the hardness due to nitrogen and oxygen, but is brittle, and cracks may occur when a large load is applied to an inner ring, an outer ring, or the like of a sliding bearing made of a titanium alloy having such a hardened layer. Further, if oxygen is dissolved in a solid solution by such a surface modification method, the grains of the titanium alloy are coarsened, and thus there is also a problem that the fatigue strength is lowered.

Further, if a hardened layer of titanium nitride is formed by vapor deposition, the hardened layer of titanium nitride may be peeled off when a large load is applied to the titanium alloy and the alloy slides at a high sliding speed.

Accordingly, an object of the present invention is to solve the problem of the modification treatment accompanying the surface hardening of the titanium alloy sliding bearing described above, and to obtain a titanium alloy sliding bearing which can secure toughness of the sliding surface, realize high hardness of the sliding surface, and suppress a decrease in fatigue strength.

In order to solve the above problems, the present invention provides a sliding bearing made of a titanium alloy, the sliding bearing having a sliding surface made of an α + β type or α type titanium alloy, the sliding surface including primary α crystal grains and secondary α crystal grains, and an oxygen diffusion layer having an oxygen concentration which decreases continuously with the depth from the surface of the sliding surface, the surface containing oxygen dissolved in a solid state at an oxygen concentration of 0.8 mass% or more, and the surface having a hardness of 550Hv or more.

The sliding bearing made of a titanium alloy of the present invention configured as described above has a sliding surface reinforced with oxygen dissolved in a solid state at an oxygen concentration of 0.8 mass% or more and hardened to a hardness of 550Hv or more by the oxygen diffusion layer provided on the surface of the sliding surface.

In addition, in the sliding surface made of an α + β type or α type titanium alloy, secondary α crystal grains smaller than primary α crystal grains are contained together with primary α crystal grains, and fatigue strength is improved by the refined crystal grain size, whereby sufficient toughness of the sliding surface can be ensured as a sliding bearing.

In a sliding bearing made of a titanium alloy in which fatigue strength is improved by the miniaturization of the crystal grain size, an oxygen diffusion layer is provided to improve the hardness of the sliding surface.

The oxygen diffusion layer is formed on the sliding surface made of a titanium alloy so that the oxygen concentration decreases continuously with the depth from the surface, and therefore, the oxygen diffusion layer is integrated with the inside of the titanium alloy with good adhesion, and is formed in a state in which the oxygen diffusion layer is not easily peeled off. That is, the oxygen diffusion layer improves the strength, hardness, corrosion resistance, and wear resistance of the surface of the titanium alloy, and does not reduce the fatigue strength of the entire titanium alloy.

In order to improve the tensile strength, creep strength, and the like as much as possible, the titanium alloy preferably contains aluminum (Al) which is a stabilizing element of the α phase to some extent (7 mass% or less), and for example, a Ti-6Al-4V titanium alloy containing 6 mass% of aluminum (Al) and 4 mass% of vanadium (V) is preferably used.

In order to improve the fatigue strength, it is preferable that the average grain size of all crystal grains having a minute secondary α phase combined with oxygen atoms is 15 μm or less, and for such average grain size, in an observation image of EBSD measurement, a difference in crystal orientation of 15 ° or more is regarded as a grain boundary, and areas are added in descending order from an aggregated crystal grain having a large grain area over the entire area of the observation image, and an average value of the crystal grain sizes up to crystal grains of 70% of the total grain area in the observation image area is obtained, and in this case, it is confirmed that the surface of the sliding surface is composed of crystal grains having an average grain size of 15 μm or less.

The sliding bearing to which the present invention is applicable is, for example, a spherical sliding bearing, and may be a titanium alloy spherical sliding bearing in which an inner ring and an outer ring are in sliding contact with each other via a lubricating bush.

In order to produce a titanium alloy sliding bearing that can be used in a low-pressure or vacuum environment, further, in an extremely low-temperature environment or an environment with a large temperature change, such as an aerospace device, the lubricating bush is preferably a bush formed of a resin molded body or woven fabric.

In the case where the lubricating bush is a resin molded body, in order to obtain a titanium alloy sliding bearing that is resistant to use in the specific environment, it is preferable to use a molded body of at least 1 resin selected from the group consisting of polytetrafluoroethylene, polyamide, polyimide, and polyphenylene sulfide.

Similarly, when the lubricating bush is a bush made of woven fabric, in order to obtain a titanium alloy sliding bearing that is resistant to use in the specific environment, it is preferable to use a woven fabric made of 1 or more fibers selected from the group consisting of polytetrafluoroethylene fibers, aromatic polyamide fibers, glass fibers, and polyester fibers.

The above sliding bearing made of titanium alloy can be used as a sliding bearing made of titanium alloy for aerospace equipment.

The sliding bearing made of the titanium alloy has the following advantages: the sliding bearing made of a titanium alloy is capable of achieving high hardness of the sliding surface and suppressing reduction of fatigue strength while securing toughness of the sliding surface because the sliding surface contains primary alpha crystal grains and secondary alpha crystal grains, the fatigue strength is improved along with the refinement of the crystal grain size, and the hardness of the sliding surface provided with the oxygen diffusion layer is improved.

Drawings

Fig. 1 is a sectional view of a spherical sliding bearing made of a titanium alloy according to embodiment 1.

Fig. 2 is a sectional view of the spherical sliding bearing made of the titanium alloy according to embodiment 2.

Fig. 3 is a sectional view of the titanium alloy sliding bearing according to embodiment 3.

Fig. 4 is a graph showing the relationship between the depth from the surface of the inner wheel material of the example and the hardness (Hv).

Fig. 5 is a graph showing the relationship between the depth from the surface of the inner wheel material and the oxygen concentration in the example.

Fig. 6 is a photograph showing an alternative image used for EBSD measurement of the surface of the inner wheel material of the example.

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings.

As shown in fig. 1, embodiment 1 is an oil-free spherical sliding bearing a made of a titanium alloy, in which a sliding surface 2 having a convex spherical surface is provided on an outer periphery of an inner ring 1 made of a titanium alloy, and an outer ring 4 having an inner periphery of a concave spherical surface is combined so as to be in sliding contact with the sliding surface 2 via a lubricating bush 3.

The sliding surface 2 of the inner ring 1, which the lubricating bush 3 contacts, contains primary alpha crystal grains and secondary alpha crystal grains, and an oxygen diffusion layer 5 is provided in which the oxygen concentration decreases continuously with the depth from the surface of the sliding surface 2.

The inner ring 1 is formed of an α + β type or α type titanium alloy, the sliding surface (surface) 2 has oxygen dissolved therein at an oxygen concentration of 0.8 mass% or more, and the sliding surface (surface) 2 has a hardness of 550Hv or more.

The lubricating liner 3 is made of a molded article made of a resin or a fiber having self-lubricating properties, woven fabric, or a composite material thereof, and is held and integrated with the outer ring 4. The resin lubricating bush 3 is mainly composed of a resin such as polytetrafluoroethylene, polyamide, polyimide, or polyphenylene sulfide, and is formed into an annular body such as a spherical shape on the inner and outer diameter surfaces by a known molding method such as injection molding. The fiber-made lubricative liner 3 is formed by bonding a woven fabric made of a fiber material such as polytetrafluoroethylene fiber, aramid fiber, glass fiber, or polyester fiber to the inner peripheral surface of the outer ring 4 with a predetermined binder.

The sliding bearing made of a titanium alloy of the present invention can be used as a sliding bearing of a known form. For example, as shown in fig. 2, the refuelling type spherical sliding bearing B of embodiment 2 has a sliding surface 2 of a convex spherical surface on the outer periphery of an inner ring 6 made of titanium alloy, and an outer ring 4 made of titanium alloy formed on the inner periphery of the concave spherical surface, and the outer ring 4 has a sliding surface 7 which is in sliding contact with the sliding surface 2 so as to face each other, and the oxygen diffusion layer 5 is formed on each of the pair of sliding surfaces 2 and 7 including primary α crystal grains and secondary α crystal grains. In the figure, reference numeral 8 denotes an oil supply hole passing through the sliding surface 2, and reference numeral 9 denotes an oil groove.

Alternatively, like the sleeve-type sliding bearing C according to embodiment 3 shown in fig. 3, the inner peripheral surface side of the cylindrical sleeve 10 made of a titanium alloy may be used as the sliding surface 11, the sliding surface 11 may contain primary α crystal grains and secondary α crystal grains, and the oxygen diffusion layer 5 may be further provided.

As the titanium alloy forming the sliding surface in any of the above embodiments, an α + β type or an α type titanium alloy is used.

For example, Ti-6Al-4V, Ti-6Al-2Sn-4Zr-6Mo is given as an example of the α + β type titanium alloy, and Ti-5Al-2.5Sn and Ti-8Al-1Mo-1V is given as an example of the α type titanium alloy.

The sliding surface of the sliding bearing made of a titanium alloy as described above is reinforced by dissolving oxygen in a solid solution in an α + β type or α type titanium alloy in a pickling step to increase the surface hardness, but the titanium alloy on the surface in which oxygen is dissolved in a solid solution contains a plurality of α crystal grains.

The α crystal grains mean crystal grains composed of an α phase. The alpha grains comprise primary alpha grains and secondary alpha grains. Primary α grains are grains composed of a primary α phase. Secondary alpha grains are grains composed of a secondary alpha phase.

The primary α phase is an α phase remaining without being converted into a β phase in the solutionizing step, the aging step, and the pickling step, which will be described later.

In addition, the secondary α phase is a phase formed by martensitic transformation or massive transformation upon cooling after being temporarily transformed into the β phase. The secondary alpha phase comprises an alpha 'phase of hcp structure and an alpha' phase of orthorhombic structure.

Primary alpha grains and secondary alpha grains can be identified by shape. The primary alpha grains have an elliptical shape and the secondary alpha grains have a needle-like shape.

Individual alpha grains are identified by crystal orientation. More specifically, in the case where the deviation of the crystal orientation of a certain α crystal phase from the crystal orientations of other α crystal phases adjacent to the α crystal phase is less than 15 °, these α crystal phases are regarded as one α crystal grain.

On the other hand, when the deviation of the crystal orientation of a certain α crystal phase from the crystal orientation of another α crystal phase adjacent to the α crystal phase is 15 ° or more, these α crystal phases are regarded as single α crystal grains.

The crystal orientation (specifying the individual α -grain boundaries) is measured, for example, by the ebsd (electron Back Scatter diffraction) method.

Using the above-described measurement method, if the size of the α crystal grains contained in the titanium alloy located on the surface of the sliding surface of the present invention is measured, it is distinguished into the 1 st group and the 2 nd group, and the minimum value of the crystal grain diameters of the α crystal grains belonging to the 1 st group is larger than the maximum value of the crystal grain diameters of the α crystal grains belonging to the 2 nd group. The value obtained by dividing the total area of the alpha crystal grains belonging to group 1 by the total area of the alpha crystal grains is 0.7 or more. After the α crystal grains having the smallest crystal grain size belonging to group 1 are excluded, the value obtained by dividing the total area of the α crystal grains belonging to group 1 by the total area of the α crystal grains is less than 0.7.

From another point of view, the α crystal grains contained in the titanium alloy located on the surface of the sliding surface are assigned to group 1 in order of the larger crystal grain size. Then, when the total area of the α crystal grains assigned to the 1 st group exceeds 0.7 times the total area of the α crystal grains for the first time, assignment to the 1 st group is stopped, and the remaining α crystal grains are assigned to the 2 nd group.

The "α crystal grains located on the surface" means α crystal grains included in a region located between the surface of the sliding surface and a position at a distance of 250 μm from the surface. The "α crystal grains located on the surface" may also be α crystal grains contained in a region located between the surface of the sliding surface and a position at a distance of 300 μm from the surface.

The average particle diameter of the alpha crystal grains belonging to group 1 is 25 μm or less. The average particle diameter of the α crystal grains belonging to group 1 is preferably 15 μm or less. The average particle diameter of the α crystal grains belonging to group 1 can be calculated from the equivalent circle diameter of each crystal grain.

As described above, from the observation image of the surface of the sliding surface in the EBSD method, when the difference in crystal orientation of 15 ° or more is regarded as a grain boundary, and areas are added in descending order from the aggregated crystal grains having a large crystal grain area over the entire observation image, and an average value of crystal grain diameters up to 70% of the total crystal grain area in the observation image area is obtained, it is confirmed that the average grain diameter is composed of crystal grains having an average grain diameter of 15 μm or less.

The titanium alloy contains oxygen (O) in an amount of 0.8 mass% or more on the surface thereof. The titanium alloy preferably contains 1.4 mass% or more of oxygen on the surface. More preferably, the titanium alloy contains oxygen in an amount of 1.8 mass% or more on the surface. The oxygen concentration in the titanium alloy was measured by epma (electron Probe Micro analyzer).

As described above, in the manufacturing process of the titanium alloy sliding bearing having the sliding surface including the primary α -crystal grains and the secondary α -crystal grains, the manufacturing process can be performed through the preparation process, the solutionizing process, the aging process, the pickling process, and the post-treatment process as described below.

In the preparation step, the inner ring or the outer ring having a sliding surface of either the α + β type titanium alloy or the α type titanium alloy is cut into a size and a shape close to the size of the final product.

In the solution treatment step, the inner ring or the outer ring, etc., which are processed into a predetermined shape in the preparation step, are heated and held in a furnace at a predetermined temperature and for a predetermined time.

At this time, argon gas or the like is introduced into the furnace as an inert gas under normal pressure. Helium, nitrogen, or the like, which is a rare gas, may be used as the inert gas.

In the solution treatment step, a holding step and a cooling step are essential steps.

In the holding step, the processing target is held at a predetermined holding temperature (hereinafter referred to as "1 st temperature") in the furnace for a predetermined time (hereinafter referred to as "1 st time").

In the solution treatment step, a part of the α phase in the titanium alloy constituting the target material is converted into the β phase.

The above-mentioned 1 st temperature is lower than the β single phase transformation point of the titanium alloy constituting the target. The β single-phase transformation point is a temperature at which all of the α phase in the titanium alloy constituting the target material is transformed into the β phase.

The cooling step is performed after the holding step. In the cooling step, the target material having passed through the holding step is cooled. Thus, the α phase converted to the β phase in the holding step becomes a secondary α phase.

The aging treatment step is performed for the purpose of precipitating secondary alpha grains smaller than the primary alpha grains after the solutionizing treatment step.

In the aging treatment step, the target is kept at a predetermined temperature (hereinafter referred to as "2 nd temperature") for a predetermined time (hereinafter referred to as "2 nd time") and then cooled. In the aging step, minute secondary α grains are precipitated from the β phase that has not been converted into the α phase in the cooling step.

In the heating and holding, argon, helium which is a rare gas, nitrogen, or the like is introduced as an inert gas into the furnace at normal pressure.

In the pickling step, pickling is performed after the solutionizing step and the aging step to form an oxygen diffusion layer having high hardness.

The pickling process is performed by holding the target at a predetermined holding temperature (hereinafter referred to as "3 rd temperature") for a predetermined time (hereinafter referred to as "3 rd time").

The pickling process includes a step of adding carbon dioxide (CO)₂) Is carried out in the atmosphere of (1). The atmosphere gas may further contain an inert gas. The inert gas is, for example, a rare gas such as argon (Ar) helium (He). The inert gas may also be nitrogen (N)₂). The pressure of the atmosphere gas is preferably normal pressure (atmospheric pressure).

The above-described series of treatment steps may be performed on the entire surface of the treatment target such as the inner ring and the outer ring, or when only the sliding surface is subjected to the pickling treatment, an oxygen diffusion layer may be provided by masking a part of the treatment target.

The treatment conditions in the pickling step are described in more detail below.

Namely, introducing CO based on argon gas into a furnace under normal pressure₂And a gas for heating and holding the titanium alloy member in the furnace and then cooling the member. If at CO₂Heating the titanium alloy in a gas atmosphere to form CO on the surface of the titanium alloy member₂The gas dissociates into O and C, and these elements diffuse and penetrate from the surface to the interior. Since carbon has a narrower solid solution limit in titanium than oxygen, it hardly affects the solid solution strengthening of the target material.

As the post-treatment step, after the pickling treatment step, machining such as turning and polishing is performed to finish the target material to a predetermined dimensional accuracy, and further, if necessary, the bush is molded and bonded, and other assembly processing is performed.

That is, TiC or TiO is formed on the surface layer of the titanium alloy after the acid immersion treatment₂Or formation of TiO structuresHowever, since the compound layer is brittle although it has high hardness, the surface layer is removed in the machining in the post-treatment step. After the pickling treatment, machining such as turning and polishing is performed to finish the workpiece to a predetermined dimensional accuracy.

The sliding surface of the inner ring manufactured by the above series of steps has an oxygen concentration of about 0.8 mass% or more and a hardness of about 550Hv or more. In an EBSD observation image of the sliding surface, a crystal orientation difference of 15 DEG or more is defined as a grain boundary, and the areas of the crystal grains are added in descending order from the aggregated crystal grains having a large crystal grain area over the entire EBSD image area to obtain an average crystal grain diameter of crystal grains of 70% of the total crystal grain area in the EBSD image area, and in this case, the surface of the sliding surface is constituted by crystal grains having an average grain diameter of 15 μm or less.

The sliding bearing made of the titanium alloy having high specific strength according to the embodiment manufactured as described above is a sliding bearing having high hardness and excellent fatigue strength, which is capable of securing fatigue strength by grain refinement in solutionizing and aging treatment and also capable of providing an oxygen diffusion layer having high hardness in the subsequent pickling treatment.

Examples

The material of the inner ring 1 (FIG. 1) of a spherical sliding bearing made of Ti-6Al-4V which is an α + β type titanium alloy conforming to ASTM B348-13 GR.5 is subjected to a solution treatment step and an aging treatment step.

The outer peripheral surface of the material of the inner ring (hereinafter referred to as "sample") was measured at a predetermined depth by scraping the sample from the surface to a depth of 0.5mm little by little, and the relationship between the depth (mm) of Hv and the depth (mm) from the initial surface at each depth was shown in fig. 4.

Fig. 5 shows the relationship between the vickers hardness (Hv) and the oxygen concentration (% by mass) measured by EPMA and the depth (mm) from the surface to the depth of 0.5 mm.

Here, fig. 4 and 5 show the hardness and oxygen concentration distribution of the sample without the post-treatment step.

In a spherical sliding bearing as an example of a final product, only an arbitrarily set margin is removed from a surface layer of an outer peripheral surface of an inner ring by machining in a post-treatment step. Therefore, in the hardness and oxygen concentration distributions of the samples shown in fig. 4 and 5, the hardness and oxygen concentration at a position deeper than the remaining amount correspond to the hardness and oxygen concentration of the actual sliding surface (surface).

Here, the machining after the pickling treatment is preferably performed with a margin within a range where the oxygen diffusion layer as the hardened layer is not removed as much as possible, and the margin is generally less than 0.10 mm. For reference, the hardness and oxygen concentration of the sliding surface (surface) when the sliding surface of the bearing was formed with a margin of 0.10mm from the surface of the sample shown in the figure were 547Hv and 0.78 mass%.

Fig. 6 shows EBSD images of the surface layer when the bearing sliding surface was formed with a margin of 0.10mm from the surface of the sample.

As is clear from the EBSD image of fig. 6, the average grain size of the α crystal grains in the sample measured was 10.1 μm. In addition, it was confirmed that the secondary α crystal grains precipitated by solid solution and aging were a minute needle-like secondary α phase as appeared in the EBSD image.

The measurement conditions of the average particle diameter at this time were: the difference in crystal orientation was defined as 15 ° or more as a grain boundary, and the areas were added in descending order from the aggregated crystal grains having a large crystal grain area over the entire EBSD image area and measured as an average value of crystal grain diameters of crystal grains up to 70% of the total crystal grain area in the EBSD image area.

It is understood that the spherical sliding bearing of the example obtained as described above has an average grain size of α grains having minute secondary α grains of as small as 10.1 μm, and then has been subjected to pickling treatment to dissolve sufficient oxygen in the surface, and therefore the sliding surface (surface) has a hardness of about 550Hv and an oxygen concentration of about 0.8 mass%, and even if made of a lightweight titanium alloy, has wear resistance and high fatigue strength, and can be used under service conditions where strength with good durability is required.

Industrial applicability

The present invention relates to a sliding bearing for aerospace equipment, and more particularly, to a sliding bearing that can be used as a sliding bearing having general-purpose properties in applications where weight reduction and durability are required, and can also be used as a sliding bearing that operates in one-way rotation with oscillation of sliding.

Description of the symbols

1. 6 inner wheel

2. 7, 11 sliding surface

3 lubricating bush

4 outer wheel

5 oxygen diffusion layer

8 oil feeding hole

9 oil groove

10 sleeve

A. B spherical surface sliding bearing

C-sleeve type sliding bearings.