JP2021110345A - Spherical slide bearing - Google Patents

Abstract

To reduce the wear of a liner in a use state by preventing a thermosetting resin which is immersed into and held at a woven cloth from being removed from the woven cloth, in a spherical slide bearing having the liner in which a low-friction characteristic of a fluorine resin is sufficiently utilized.SOLUTION: A spherical slide bearing comprises a sheet-shaped liner 4 having a prescribed thickness which is adhesively fixed to an internal peripheral face 1a of an outer ring 1 via an adhesive layer 3. The liner 4 is formed of a sheet-shaped composite body which is obtained by complexing a woven cloth composed of synthetic fibers integrated with fluorine fibers or fluorine resins, and a thermosetting resin impregnated in the woven cloth. A thickness of the liner is 200 to 390 μm, and a deformation amount of the liner 4 caused by an applied load and the vibration of inner/outer rings, and a wear amount related to the deformation amount are suppressed.SELECTED DRAWING: Figure 1

Description

The present invention relates to a spherical plain bearing, and more particularly to a spherical plain bearing in which a liner is interposed between an inner ring and an outer ring.

Generally, a spherical plain bearing includes an inner ring having an outer peripheral surface of a convex spherical surface and an outer ring having an inner peripheral surface of a concave spherical surface to slidably hold the inner ring, and the inner and outer rings rotate while receiving a load. A well-known spherical plain bearing is a bearing that allows the shafts of both wheels to tilt by moving or swinging, and has a self-lubricating liner that can supply a solid lubricant to the sliding surface between the inner and outer rings. be.

As a spherical slide bearing having excellent lubricity and wear resistance even under a high load condition, a liner provided between the inner and outer rings is known to be made of an ether-urea polymer (Patent Document 1). ..

Although this spherical plain bearing has a ^{property of withstanding a high load exceeding 500 kgf / cm 2} , it cannot obtain lubricity having an extremely small friction coefficient like a liner using a fluororesin polymer.

Further, the liner is a mixture of 60 to 80% by weight of a polyetherketone resin, 10 to 30% by weight of polytetrafluoroethylene (PTFE), 5 to 15% by weight of carbon fibers, and 15% by weight or less of aramid fibers. A spherical plain bearing formed of a certain self-lubricating resin composition is known (Patent Document 2).

Such a liner can be dimensionally adjusted by grinding or cutting, but if a large amount of PTFE is added, the compression creep property and the wear resistance are lowered.

Further, as a liner, a liner formed of a fabric (woven fabric) made of polytetrafluoroethylene (PTFE) and polyaramid fibers into a sheet shape and impregnated with a phenol resin (according to the international standard SAE-AS81820) is known. It has been suggested that this may be used for spherical plain bearings (Patent Document 3).
Since such a liner is reinforced with a woven fabric, it has a high compression creep property, and a large amount of PTFE can be supplied to the sliding surface by the PTFE constituting the woven fabric.

Jikkenhei 7-41058 Japanese Unexamined Patent Publication No. 2011-247408 Japanese Unexamined Patent Publication No. 2007-255712

However, the spherical slide bearing provided with the relatively thick sheet-like liner described in Patent Document 3 described above has a surface of the liner that slides according to a change in the angle of each axis when the inner and outer rings swing. Since both sides of the fixed bottom surface receive a force in the direction of being displaced in parallel, and both sides are compressed by receiving a load from each axis and are susceptible to vibration, the phenol resin that has penetrated into the woven fabric is It is considered that the woven fabric whose mesh shape and size fluctuate slightly is likely to be separated from the woven fabric little by little, and as a result, there is a problem that the liner is easily worn.

As described in Patent Document 2, when a liner composed of a self-lubricating resin composition containing PTFE and reinforcing fibers is adopted, the reinforcing fibers are uniformly dispersed, so that the dimensions can be adjusted by appropriately cutting. However, the fluorine-based lubrication characteristics as in the case of adopting a woven fabric in which fluorine fibers are blended cannot be sufficiently exhibited.

Therefore, the subject of the present invention is to solve the above-mentioned problems and to soak the liner into the woven fabric of the liner in a spherical plain bearing formed of a fabric (woven fabric) that fully utilizes the low coefficient of friction of the fluororesin. By preventing the thermosetting resin held in the above from separating from the woven fabric as much as possible in the state of use, it is possible to obtain a spherical plain bearing having excellent lubricity of fluororesin and excellent wear resistance. be.

The inventors of the present application have elastically deformed the woven fabric so that the thermosetting resin does not separate from the gaps between the fibers of the woven fabric in order to suppress wear in the use state of the spherical plain bearing provided with the fluorine fiber fabric. I thought it was necessary not to be too big.

Therefore, in the present invention, an outer ring having a spherical inner peripheral surface, an inner ring having a spherical outer peripheral surface facing the inner peripheral surface with a gap, and an outer peripheral surface of the inner ring and the inner ring of the outer ring. A sheet-like liner having a predetermined layer thickness that is fixed to one of the peripheral surfaces and fills the gap is provided, and the liner includes a woven fabric made of fluorofiber or synthetic fiber integrated with fluororesin, and a thermosetting resin. A spherical slide bearing having a predetermined layer thickness of 200 to 390 μm is formed of the composite of the above.

In the spherical slide bearing of the present invention configured as described above, since the sheet-shaped liner having a woven fabric of a predetermined material is formed to have a thickness within a predetermined range, the angle of each axis during use can be changed. The surface that slides accordingly and the fixed bottom surface do not deform so much in the direction of shifting both sides in parallel. Therefore, the shape and size of the mesh of the woven fabric do not fluctuate so much, and the thermosetting resin adhering to or held between the fibers and threads of the woven fabric or on the surface thereof does not easily come off, and has excellent abrasion resistance. It will be equipped with a liner.

That is, by using a spherical slide bearing having a thickness of the liner of 200 to 390 μm, deformation and wear of the liner due to a load and swing of the inner and outer rings are remarkably reduced.

Further, in order to reduce the friction coefficient of the liner as much as possible and further enhance the abrasion resistance, the synthetic fiber integrated with the fluorine fiber shall be a synthetic fiber composed of a blended fiber of polytetrafluoroethylene fiber and polyaramid fiber. Is preferable. For the same reason, it is also preferable that the synthetic fiber integrated with the fluororesin is a synthetic fiber made of polyaramid fiber coated with polytetrafluoroethylene.

In addition, the liner, which is composed of a composite by sufficiently impregnating a woven fabric with a thermosetting resin such as a liquid phenol resin and heat-curing it, is made of a thermosetting resin having high heat resistance. It becomes difficult to peel off from the resin, that is, it becomes difficult for the thermosetting resin to come off.
By increasing the wear resistance of the liner in this way, the durability of the spherical slide bearing in use can be increased, and the bearing life can be improved.

In the present invention, since the layer thickness of the liner having the woven fabric layer of the predetermined material in the spherical slide bearing is provided in the above-mentioned predetermined range, the liner is soaked and held in the woven fabric in the spherical slide bearing formed of the fabric (woven fabric). The heat-curable resin is hard to peel off from the fibers of the woven fabric, the wear resistance of the liner is improved, and there is an advantage that the lubricity of the spherical plain bearing and the durability of use can be sufficiently enhanced.

Sectional drawing which shows the spherical plain bearing of embodiment A perspective view of a cross section of a main part of the spherical slide bearing shown in FIG. Explanatory drawing of the swing state of the inner ring of the spherical plain bearing of FIG. Schematic configuration explanatory view of the wear test device as viewed from the front Schematic configuration explanatory view of the wear test device as viewed from the side

Embodiments of the present invention will be described below with reference to the accompanying drawings.
As shown in FIGS. 1 and 2, the spherical slide bearings of the embodiment are formed on an inner ring 2 having a spherical outer peripheral surface 2a facing the spherical inner peripheral surface 1a of the outer ring 1 and an inner peripheral surface 1a of the outer ring 1. It is bonded and fixed by the adhesive layer 3 and includes a sheet-shaped liner 4 having a predetermined thickness.

The outer ring 1 and the inner ring 2 are made of a composite material such as a titanium alloy or other well-known metal material or a dissimilar metal, or a surface-hardened material thereof.
The illustrated outer ring 1 has a substantially cylindrical shape, and its inner peripheral surface 1a has a spherical shape having a diameter slightly larger than the outer peripheral surface 2a of the inner ring 2, and the inner peripheral surface 1a is for improving the adhesive force of the adhesive. The surface is roughened by shot blasting.

The liner 4 is made of a sheet-like composite of a woven fabric made of a fluorofiber or a synthetic fiber integrated with a fluororesin and a thermosetting resin impregnated therein, and has a thickness of 200 to 390 μm. The specific thickness capable of suppressing the amount of deformation of the liner 4 due to the load and the swing of the inner and outer rings and the amount of wear associated therewith is limited to the above numerical range, more preferably 250 to 380 μm, and further preferably. Is 280 to 350 μm, and particularly preferably 290 to 335 μm.

As the fluorofiber, a well-known fluoropolymer such as tetrafluoroethylene (TFE), chlorotrifluoroethylene (CTFE) or a polymer of these, PTFE or PCTFE is used as a raw material, and mixed with a matrix polymer such as biscous to form an emulsion. , It is made into fibers by a well-known method such as extruding from a molding base into a coagulation bath to form fibers (matrix method).

An example of a synthetic fiber integrated with a fluorine fiber is a synthetic fiber in which a fluorine fiber and a synthetic fiber serving as a reinforcing material are blended, and a polytetrafluoroethylene (PTFE) fiber and a polyaramid having excellent heat resistance and high strength are used. Synthetic fibers made of blended fibers with fibers are preferred.
The blending ratio of the fluorofibers and the synthetic fibers is preferably adjusted to give the liner the required low coefficient of friction and fabric strength depending on the application of the spherical plain bearing.

The above-mentioned fluorine (PTFE) fiber has a water absorption rate of 0%, a melting temperature of 327 ° C., can be used up to a high temperature of 260 ° C., has good high temperature characteristics, and has extremely high chemical resistance and weather resistance. It can also be applied to spherical plain bearings for applications such as aircraft.

Examples of the synthetic fiber integrated with the fluororesin include synthetic fibers made of polyaramid fibers coated with a fluororesin such as PTFE. Such synthetic fibers are made of polyaramid fibers (heat-resistant nylon) or the like, and the woven fabric made of such synthetic fibers is impregnated with a fluororesin dispersion liquid, dried, and then fired to be composited with the fluororesin and integrated. It can also be made into.

The woven fabric made of synthetic fibers used in the present invention is obtained by processing the above-mentioned synthetic fibers into a well-known woven fabric such as a plain weave or a mesh-like cloth, which is called a fabric. Further, the required number of sheets can be piled up, and if necessary, the fabrics can be formed by heating, pressurizing or the like so as to connect the ends to each other to obtain a woven fabric for a liner having a required thickness in the required form.

Examples of synthetic fibers that can be used in addition to aromatic polyamide fibers include glass fibers, carbon fibers, polyester fibers, and the like.

In order to maintain the shape (pressure resistance) and hardness of such a woven fabric as a liner, it is necessary to impregnate such a woven fabric with an uncured (liquid) state of a thermosetting resin having good heat resistance such as phenol resin. After drying accordingly, heat and / or pressurize to cure. It is preferable to impregnate a liquid resol-type phenol resin having a self-reactive functional group and heat it until the phenol resin is cured.

Adjusting the viscosity of the thermosetting resin used at this time in the uncured (liquid) state (for example, adjusting the amount of diluent or filler, etc.), the size of the molding frame (depth in the frame), or the heating step The thickness of the sheet-shaped liner can be adjusted by adjusting the distance between a pair of facing heating rollers arranged so as to pass the sheet through the path.

In order to fix the liner 4 to either the outer peripheral surface 2a of the inner ring 2 or the inner peripheral surface 1a of the outer ring 1, fixing with an adhesive is an easy and appropriate means and is preferable. As the adhesive, an adhesive having good adhesiveness (affinity) with the thermosetting resin described above may be selectively adopted, and when a phenol resin is adopted, a phenol resin-based adhesive which is a thermosetting resin is used. The adhesive is suitable.

The liner 4 formed of the above resin as a material is preferable because it has excellent wear resistance and heat resistance, has high load resistance, has high thermal conductivity, and has a small coefficient of thermal expansion.
For example, a liner 4 is adhered to an outer ring 1 or an inner ring 2 made of a titanium alloy or other metal such as Ti-6Al-4V as a material of a spherical plain bearing, and this is press-fitted into the corresponding inner ring 2 or the outer ring 1. By incorporating the above, a spherical plain bearing can be manufactured.

The spherical plain bearing obtained as described above is used in a state where the axial directions of the outer ring 1 and the inner ring 2 coincide with each other on a straight line (FIGS. 1 and 2), and as shown in FIG. When the axial directions of the outer ring 1 and the inner ring 2 change during use, the outer peripheral surface 2a of the inner ring 2 is in the direction of the arrow in the drawing relative to the liner 4 fixed to the inner peripheral surface 1a of the outer ring 1. Swing to.

At this time, the surface of the liner 4 that slides according to the change in the angle of each axis and the bottom surface to which the liner 4 is adhered receive a force in the direction of shifting both sides in parallel. However, if the thickness of the liner 4 is a spherical slide bearing in a predetermined range of 200 to 390 μm, as is clear from the test results described later, the liner 4 is deformed and worn due to the load and the swing of the inner and outer rings. It will be less and more durable.

[Example 1-7, Comparative Example 1-6]
As the outer ring of the oil-free titanium alloy spherical plain bearing, the inner circumference of the concave spherical surface is formed on the inner circumference of the outer ring made of Ti-6Al-4V titanium alloy, and the inner peripheral surface is roughened by shot blasting. , A sheet-shaped lubricating liner prepared in advance with a phenol resin-based adhesive was adhered and fixed.

The material of the liner is a sheet-shaped plain woven fabric made of a blended fiber of polytetrafluoroethylene (PTFE) and polyaramid, which is impregnated with a resol type phenol resin solution and dried, and this is used as an outer ring or a wear evaluation test piece. On the other hand, it is pressure-bonded using a phenol resin-based adhesive. The viscosity of the resole-type phenol resin solution is appropriately adjusted, and the thickness of the sheet-like liner that has been dried, pressed and cured is adjusted to a predetermined range (approximately 250 to 380 μm in the examples and approximately 395 to 470 μm in the comparative examples). Then, a sheet-like liner integrated with the outer ring or the wear evaluation test piece used in Examples 1-7 and Comparative Example 1-6 was prepared.

Further, a prefabricated inner ring made of a titanium alloy of Ti-6Al-4V having a convex spherical sliding surface formed on the outer circumference and thermosetting to have a surface hardness of 650 HV has been described above. The outer rings were press-fitted and combined to manufacture spherical plain bearings of Examples 1-7 and Comparative Example 1-6 having the same embodiments as those described above.

In order to investigate the relationship between the thickness of the liner of the obtained spherical plain bearing and the wear resistance, a wear test was performed under the test conditions shown in Table 1 below using a testing machine whose schematic configuration is shown in FIGS. Are shown in Tables 2 and 3. Further, in Tables 2 and 3, the thicknesses of the sheet-like liners of Examples and Comparative Examples are shown, and for reference, those having a wear depth of 115 μm or less are marked with a circle, and those having a wear depth of more than 115 μm are marked with a cross. Evaluated the quality.

[Abrasion evaluation test]
As shown in FIGS. A block-shaped test piece (liner) A is fixed so as to be in contact with the upper part (raised portion) of the ring 6 by attaching a hardness of 650 HV, a rotation (maximum) diameter of 32 mm, and a curvature R of a raised portion continuous in the circumferential direction R = 5 mm). Then, a load W is applied downward from the upper part of the test piece A to rotate the ring 6 in the forward and reverse directions so as to swing within a rotation angle of ± 25 °, so that the liner of the spherical plain bearing receives a sliding state. Was reproduced, and the wear depth (μm) at a predetermined number of swings was measured to evaluate the wear resistance.

Using such a testing machine, a liner test piece of Example or Comparative Example is adhered and fixed to a rectangular flat plate (length 20 mm, width 10 mm, thickness 5 mm) to which a load is applied with a phenol resin adhesive. did.

As for the rotation of the ring as a test condition, the stationary position is set to 0 °, then the position of + 25 ° with the counterclockwise direction as the positive (+) direction, the position of 0 ° in the counterclockwise (-) direction, and further. It was swung up to 25,000 cycles, with one cycle being the rotation to return to the position of 25 ° clockwise (−) and then to the stationary position of 0 ° counterclockwise.

As is clear from the results in Tables 2 and 3, the liner used in Comparative Example 1-6 had a thickness of 395 to 467 μm, and the wear depth of the test result was 122 to 191 μm, which was a remarkably large amount of wear. ..

On the other hand, the liner used in Example 1-7 had a thickness in a predetermined range of 252 μm to 379 μm, and the wear depth of the test result was stable with a relatively small amount of wear of 80 μm to 104 μm. ..
Therefore, it can be seen that the thickness of the liner is at least less than 395 μm, preferably 390 μm or less.

Further, if the thickness of the liner is less than 200 μm, even if the amount of wear of the lubricating liner during use of the bearing is reduced to about 100 μm, the wear tends to progress further, which causes the inner ring and the outer ring to come into contact with each other. Therefore, it was considered that the performance as a lubricating liner would not be stable.

The present invention relates to a spherical plain bearing used for, for example, an aircraft, an aerospace device such as an artificial satellite, etc., and is a spherical plain bearing that swings while receiving a load and allows an inclination of an axis. It can be applied to a spherical plain bearing provided with a self-lubricating liner capable of supplying a solid lubricant to its sliding surface.

In addition, as a non-lubricating spherical plain bearing, it can be used in a wide range of applications where heat resistance, wear resistance, oil resistance, etc. are required, and food machines that dislike the use of lubricating oil and regular refueling are not possible. Alternatively, it can also be used for joint movement parts of industrial equipment that is not necessary.

1 Outer ring 1a Inner peripheral surface 2 Inner ring 2a Outer outer surface 3 Adhesive layer 4 Liner 5 Main shaft 6 Ring A Specimen W Load

Claims (4)

An outer ring having a spherical inner peripheral surface, an inner ring having a spherical outer peripheral surface facing the inner peripheral surface, and an outer peripheral surface of the inner ring and an inner peripheral surface of the outer ring are fixed to each other. Equipped with a sheet-like liner of a predetermined thickness,
This liner is a spherical slide bearing having a predetermined thickness of 200 to 390 μm, which is made of a composite of a woven fabric made of a fluorofiber or a synthetic fiber integrated with a fluororesin and a thermosetting resin. The spherical sliding bearing according to claim 1, wherein the synthetic fiber integrated with the fluorine fiber is a synthetic fiber made of a blended fiber of a polytetrafluoroethylene fiber and a polyaramid fiber. The spherical slide bearing according to claim 1, wherein the synthetic fiber integrated with the fluororesin is a synthetic fiber made of polyaramid fiber coated with polytetrafluoroethylene. The spherical slide bearing according to any one of claims 1 to 3, wherein the thermosetting resin is a phenol resin.

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