JP2013210060A - Sliding bearing and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a half bearing showing excellent heat resistance property, without degrading conformability of a resin overlay layer containing solid lubricant, and a method of manufacturing the same.SOLUTION: A half bearing having a different cleavage direction, at a bearing center part and at both end parts, of a solid lubricant 110 in a resin overlay 103, is obtained by drying with an application surface of the bearing center part facing downward after applying of the resin overlay layer 103. The half bearing is provided with a different role, such as wear resistance at a center part and conformability at both end parts, thereby providing a sliding bearing which can be applied to a high performance engine such as a start/stop engine.

Description

  TECHNICAL FIELD The present invention relates to a slide bearing for an engine for automobiles and other industrial machines, and in particular, a solid lubricant on a half bearing base material having a back metal and a bearing alloy layer disposed on the back metal. And a semi-cylindrical half bearing provided with a resin overlay layer containing a binder resin.

  As a slide bearing material (sometimes simply referred to as “bearing”) for an automobile engine, an aluminum alloy or a copper lead alloy with a Pb-based overlay is generally used. In recent years, the performance of automobile engines with high output and high revolution has been remarkably improved, and excellent sliding performance such as initial conformability, seizure resistance, durability, and heat resistance is desired for these bearing materials.

  A bearing in which a bearing alloy layer of aluminum or copper is bonded to a back metal can ensure fatigue resistance and seizure resistance, but has insufficient initial conformability and foreign matter resistance. In addition, in order to ensure compatibility, copper lead alloy bearings further provided with a soft metal-based overlay such as Sn and Pb are not sufficient in wear resistance and require a complicated manufacturing process, resulting in a high cost. there were.

  Therefore, a resin overlay layer including a solid lubricant and a binder resin has been proposed in place of a soft metal overlay in order to ensure conformability while maintaining high fatigue resistance and wear resistance (patent) References 1 and 2). The resin overlay layer is formed by applying a solid lubricant, a diluent and a polyimide resin to an aluminum bearing alloy by spraying, drying and firing. Since the resin overlay layer containing this solid lubricant is deposited on the underlying aluminum alloy, the conformability is better than that of the soft metal overlay.

This conformability utilizes the property that a solid lubricant is very slippery on a specific crystal plane. That is, when the solid lubricant particles dispersed in the resin overlay layer are subjected to a load from the counterpart shaft, they slide on the specific crystal plane, and are deformed and destroyed. As a result, low friction and good conformability are realized. Regardless of the direction of the specific crystal plane of the solid lubricant in the resin overlay layer, the specific crystal plane slips.
On the other hand, the expected sliding performance may not be obtained when sliding at high peripheral speed and high surface pressure. It has been found that the sliding performance under high peripheral speed and high surface pressure is due to the crystal orientation dependence of the solid lubricant (Patent Document 3).

JP-A-4-83914 Japanese Patent No. 3133209 JP 2008-95725 A

However, when high conformability is obtained with respect to the sliding bearing sliding member, wear resistance, which is a contradictory property, decreases. In particular, in a start / stop engine used in recent years, it is necessary to reduce the wear of the resin coating. As described above, the sliding bearing is required to have both wear resistance and conformability, but it is difficult to achieve both characteristics at a high level, and there is room for improvement.
Accordingly, an object of the present invention is to achieve both wear resistance and conformability of a resin overlay layer in a half bearing.

  As a result of earnest study to achieve the above object, the present inventor has made the present invention by giving the solid lubricant in the resin overlay layer different orientations at the center and both ends of the bearing. It came to be completed.

That is, the present invention relates to the following <1> to <10>.
<1> A half bearing in which a resin overlay layer containing a binder resin and a solid lubricant (A) is provided on a half bearing substrate having a backing metal and a bearing alloy layer disposed on the backing steel. The solid lubricant (A) includes a solid lubricant (a) having a cleavage, and the direction of the cleavage surface of the solid lubricant (a) includes both circumferential ends of the half bearing, Half bearings that differ from the center in the circumferential direction.
<2> The angle between the cleaved surface and the sliding surface of the solid lubricant (a) at both circumferential ends of the half bearing is such that the solid lubricant (a) at the circumferential center of the half bearing. The half bearing according to the above <1>, which is smaller than an angle formed between the cleavage surface and the sliding surface.
<3> The cleaved surface of the solid lubricant (a) is parallel to the sliding surface at both circumferential ends of the half bearing, and to the sliding surface at the circumferential central portion of the half bearing. The half bearing according to <1> or <2>, which is non-parallel.
<4> The solid lubricant (a) is, half bearing according to any one of the which is MoS ₂ <1> ~ <3>.
<5> The half bearing according to any one of <1> to <4>, wherein the resin overlay layer has a thickness of 3 to 10 μm.
<6> The half bearing according to any one of <1> to <5>, wherein the binder resin is one or more resins selected from the group consisting of a polyamideimide resin, a polyimide resin, and a polybenzimidazole resin. .
<7> The half bearing according to any one of <1> to <6>, wherein the solid lubricant (A) is 30 to 50% by volume in the resin overlay layer.
<8> The above <1> to <7>, wherein the solid lubricant (a) further contains graphite, and MoS ₂ is 40% by volume or more and less than 100% by volume with respect to the entire solid lubricant (a). The half bearing according to any one of the above.
<9> The solid lubricant (A) contains polytetrafluoroethylene, and the ratio of the solid lubricant (a) in the solid lubricant (A) is 40% by volume or more and less than 100% by volume. The half bearing according to any one of <1> to <8>.
<10> A solid lubricant (A) containing a binder resin and a solid lubricant (a) having a cleavage on a half bearing base material having a back metal and a bearing alloy layer disposed on the back metal. The method of manufacturing a half bearing including the process of apply | coating the resin overlay layer containing, the process of drying with the application surface of the bearing center part of the resin overlay layer facing down, and the baking process.

  The sliding bearing according to the present invention provides wear resistance at the central portion of the bearing that is subject to wear by making the direction of the cleaved surface of the solid lubricant having cleavage differ between the circumferential end of the half bearing and the central portion. Can be improved.

FIG. 1 is a schematic diagram showing a range of a central portion in the circumferential direction and both end portions in the circumferential direction in an axial sectional view of the half bearing. Figure 2 represents the crystal structure of MoS _2. FIG. 3 is a schematic view when the cleavage plane of the solid lubricant in the resin overlay layer is non-parallel to the sliding surface. FIG. 4 is a schematic diagram when the cleavage plane of the solid lubricant in the resin overlay layer is parallel to the sliding surface. FIG. 5 shows an XRD pattern when the relative c-axis intensity ratio in MoS ₂ as a solid lubricant is 88%. FIG. 6A is a schematic diagram showing a state of the bearing when the resin overlay layer applied on the half bearing base material having the back metal and the bearing alloy layer disposed on the back metal is dried. is there. FIG. 6B is a schematic diagram showing a state (non-parallel) of the cleaved surface of the solid lubricant in the center portion A of the half bearing. FIG. 6C is a schematic diagram showing the state (parallel) of the cleavage surface of the solid lubricant at both ends B of the half bearing.

Hereinafter, the present invention will be described in detail.
A half bearing according to the present invention includes a resin overlay layer containing a binder resin and a solid lubricant (A) on a half bearing base material having a backing metal and a bearing alloy layer disposed on the backing steel. And the solid lubricant (A) contains a solid lubricant (a) having a cleavage. The direction of the cleaved surface of the solid lubricant (a) differs between both circumferential ends of the half bearing and the circumferential central portion.
The angle between the cleaved surface and the sliding surface at both circumferential ends of the half bearing is smaller than the angle between the cleaved surface and the sliding surface at the circumferential center of the half bearing. It is preferable from the viewpoint of compatibility of wear resistance.
Furthermore, the cleaved surface of the solid lubricant (a) is parallel to the sliding surface at both circumferential ends of the half bearing, and the solid lubricant is disposed at the circumferential center of the half bearing. More preferably, the cleavage plane of (a) is non-parallel to the sliding surface.
Here, both circumferential ends of the half bearing represent a range from the circumferential ends of the half bearing shown in FIG. 1B to 20 ° toward the circumferential central portion. The portion represents a total range of 40 °, 20 ° from the center in the circumferential direction to both ends in the circumferential direction in the half bearing shown by A in FIG.

The direction of the cleavage plane of the solid lubricant (a) having cleavage in the present invention is different between the bearing central portion and both end portions. Since the bearing central portion is likely to come into strong contact with the shaft during sliding, deformation and oil film breakage are likely to occur, and wear is also likely to occur. On the other hand, it is desirable that both end portions of the bearing have a low friction property from the viewpoint of conformability with little wear during sliding.
Accordingly, the solid lubricant (a) is made non-parallel to the sliding surface at the center of the bearing, and the direction of the cleavage surface is made parallel to the sliding surface at both ends of the bearing. Parallel to In this way, by changing the direction of the cleaved surface of the solid lubricant (a) between the bearing center and both ends, the role is shared within the bearing, and a load is applied without impairing the conformability of both ends. The wear resistance of the central part can be improved.

  Here, the direction of the cleavage plane of the solid lubricant (a) being parallel to the sliding surface represents a state in which the orientation ratio of the c-axis of the solid lubricant (a) is 85% or more, Represents a state of less than 85%. The c-axis orientation rate will be described later.

  Since the solid lubricant (a) having a cleavage is easily cleaved by an external force and exhibits low friction, cleavage occurs regardless of the orientation of the cleavage surface in the resin overlay layer. On the other hand, under the sliding conditions of high peripheral speed and high surface pressure, the orientation of the cleavage plane affects the sliding performance. Therefore, by determining the orientation of the cleavage plane, a resin overlay layer exhibiting low friction can be formed even under sliding conditions of high peripheral speed and high surface pressure. Since the resin overlay layer of the sliding member may be worn away until the base is exposed, the direction of the cleaved surface of the solid lubricant in the entire thickness affects the sliding characteristics.

The orientation of the solid lubricant in the resin overlay layer can be obtained from a diffraction pattern in X-ray diffraction measurement (XRD). When the solid lubricant is MoS ₂ , the crystal structure of MoS ₂ has a layered structure in which layers made of strong bonds of molybdenum (Mo) and sulfur (S) are laminated as shown in FIG. Since the S—S bond connecting the layers is very weak, the S—S bond is weak against a force acting in parallel with the layers, and exhibits a very low coefficient of friction in slipping between layers.

Furthermore, in MoS ₂ , a hexagonal mesh Mo (B) layer is sandwiched between hexagonal mesh S (A) layers from both sides, and the structure (A-B-A) is defined as 1 unit. The laminated structure is taken. If the direction of the hexagonal mesh plane is defined as the a-axis and the stacking direction of the layers is defined as the c-axis, the plane orientation of the c-axis is (001). In the X-ray diffraction measurement, this is an integer multiple of 2 (002). Peaks on the (004) and (008) planes are detected. Since the (002), (004) and (008) planes correspond to the cleavage direction of the MoS ₂ particles, it can be said that the more the (002), (004) and (008) planes, the higher the c-axis orientation ratio. It means that the direction of the cleavage plane is parallel to the sliding surface. On the other hand, a low relative c-axis strength ratio means that the direction of the cleavage plane of the MoS ₂ particles, which are solid lubricants, is non-parallel to the sliding surface.

  That is, the c-axis orientation ratio can be represented by the relative c-axis intensity ratio represented by the following formula (1) from the diffraction pattern in the X-ray diffraction measurement.

  Relative c-axis intensity ratio = [{total of integrated intensity of (002), (004), (008) plane} / {(002), (004), (100), (101), (102), (103 ), (105), (110), (008) plane total intensity} × 100]% (1)

As reference values, standard samples β-MoS ₂ and J.P. The relative c-axis intensity ratio calculated by the above formula (1) from the XRD pattern of 37-1492, that is, the c-axis orientation ratio is 45.8%.

  In the X-ray diffraction measurement (XRD), when CuKα rays are used as the radiation source, the preferable output of the X-ray diffractometer is about 40 kV-100 mA. Since the X-rays reach up to, it is possible to measure the direction of the cleavage plane in the entire thickness of the solid lubricant that affects the sliding characteristics.

Next, FIGS. 3 and 4 schematically show the direction of the cleavage plane of the solid lubricant in the resin overlay layer.
When solid lubricant particles (here MoS ₂ ) are regarded as hexagonal flaky solid lubricant 10, one hexagonal flaky solid lubricant 10 has a laminated structure of (A-B-A) structure as described above. Have. In FIG. 3, the (002) axis is inclined about several degrees to 30 degrees with respect to the direction perpendicular to the film surface (the direction parallel to the sliding surface), and can be said to be non-parallel. On the other hand, in FIG. 4, the (002) axis of all the solid lubricant particles is orthogonal to the surface of the coating layer 12 (arranged parallel to the sliding surface) and can be said to be parallel. However, in practice, since all solid lubricant particles cannot be orthogonally arranged as in FIG. 4, the c-axis orientation ratio of MoS ₂ particles, which are solid lubricants, does not reach 100%. Is handled only as a schematic diagram for explaining the orientation of the solid lubricant.

Next, the crystal plane of MoS _{2 and} the peak position in the XRD pattern will be described. The (002) plane spacing of MoS ₂ is 12.3 mm, and the source wavelength (λ) when CuKα rays are used for X-ray diffraction measurement is 1.54 mm. Therefore, Bragg's diffraction formula (nλ = 2dsinθ ), The peak of the (002) plane of MoS ₂ is detected at a diffraction angle 2θ = 14.4 ° (FIG. 5: peak 1). When the diffraction peak from the (002) plane is parallel as shown in FIG. 4, a sharp and strong peak at 2θ = 14.4 ° is obtained. On the other hand, in the case of non-parallel as shown in FIG. 3, the peak at 2θ = 14.4 ° becomes broad and the peak intensity also decreases.

In addition, the diffraction angles of the (004), (100), (101), (102), (103), (105), (110), and (008) planes of MoS ₂ are similarly determined from the Bragg diffraction formula. 2θ can be obtained. FIG. 5 is an X-ray diffraction pattern (relative c-axis intensity ratio = 88%) of a resin overlay layer using MoS ₂ as a solid lubricant, and the relationship between each peak and crystal plane is also shown. In XRD, diffraction peaks showing planes other than the above nine planes may be obtained. However, since the peak intensities are extremely low, they may be ignored in the calculation of the relative c-axis intensity ratio.

Since the (002), (004), and (008) planes of MoS ₂ correspond to cleavage planes, when the relative intensity of peaks indicating these planes is high, the cleavage plane of MoS ₂ that is a solid lubricant particle It can be said that the direction is approaching the parallel shown in FIG.
Diffraction from a surface other than the cleavage plane always exists, so the relative c-axis intensity ratio does not reach 100%. However, by adjusting conditions such as film formation method condition adjustment, it can be up to about 90%. It is possible to raise it.

As the solid lubricant, if the solid lubricant (a) having cleavage is contained, one kind may be used, or two or more kinds may be used in combination. The solid lubricant having a cleavage, MoS _2, graphite, hexagonal boron nitride (h-BN), WS ₂ and the like. Further, polytetrafluoroethylene (PTFE) having no cleavage may be used in combination.
Among the solid lubricants (a), MoS ₂ is preferable from the viewpoint of lipophilicity with the lubricating oil. When MoS ₂ and other solid lubricants are used in combination, at least one of PTFE and graphite can be used, and these provide lubricating performance superior to that of MoS ₂ particularly when the lubricating oil is insufficient. Show. If further addition of graphite to the MoS _2, MoS ₂ solid lubricant (a) the overall relative 40% by volume or more, to be less than 100% by volume, preferably from the viewpoint of ensuring the orientation of MoS _2, solid lubricant When the agent (A) contains PTFE, the ratio of the solid lubricant (a) having cleavage in the solid lubricant (A) is preferably 40% by volume or more and less than 100% by volume.

When the solid lubricant (A) is used in combination with MoS ₂ and a solid lubricant having another cleavage as the solid lubricant (a) having cleavage, the relative c-axis strength ratio is determined by XRD as in the case of MoS _2. It can be used to calculate the orientation rate of the solid lubricant and to determine parallel / non-parallel.

When the solid lubricant used in combination is graphite, crystal structure of the graphite hexagonal, between carbon atoms distances a = 1.42 Å, and an interlayer distance c = 3.35 Å, of MoS ₂ previously described (A-B -A) A structure in which B is missing from the structure. In the XRD measurement, the (002), (004), and (008) planes of graphite are detected in the same manner as MoS ₂ and the relative c-axis intensity ratio can be obtained using the above equation (1) as it is.
Similar to MoS ₂ , the standard sample, graphite No. In 37-1492, the relative c-axis intensity ratio is 45.8%.

When the solid lubricant used in combination is h-BN, h-BN has a hexagonal arrangement in which three boron atoms and three nitrogen atoms are alternately arranged, and the length of one side a = 1.47Å. A common hexagonal arrangement is repeated two-dimensionally in a mesh pattern. Further, the network structure is repeated with a surface interval c = 3.33 mm in the c-axis direction, and has a layered structure similar to graphite. Therefore, in the XRD measurement, the (002), (004), (008) planes are detected for h-BN in the same way as MoS ₂ and graphite, and the relative c-axis intensity ratio is obtained using the above equation (1) as it is. Can do.
Standard sample, h-BN No. 34-0421 has a relative c-axis intensity ratio of 74.3%.
Also, when the solid lubricant used in combination is WS ₂ , since it has a layered structure like the graphite and h-BN, the relative c-axis strength ratio can be obtained by the same method.

  The solid lubricant is used in a state of being mixed with a binder resin from the viewpoint of adhesion to the bearing. The binder resin is a thermosetting resin such as polyimide resin (PI), polyamideimide resin (PAI), epoxy resin or phenol resin, or thermoplastic resin such as polybenzimidazole resin (PBI) or polyether ether ketone resin (PEEK). Can be used. Among these, PI, PAI, and PBI are preferable from the viewpoint of heat resistance and strength.

The layer containing the solid lubricant (A) and the binder resin is referred to as a resin overlay layer, and the solid lubricant (A) in the resin overlay layer is 30 to 50% by volume to ensure the orientation of the solid lubricant. To preferred.
Further, the thickness of the resin overlay layer is preferably 1 to 20 μm, and more preferably 3 to 10 μm. The thickness of the layer is considered to affect not only the orientation of the solid lubricant particles but also the adhesive strength with the base material, the strength within the layer, the thermal conductivity, and the like.

  The resin overlay layer is coated on a half bearing base material having a back metal and a bearing alloy layer disposed on the back metal, and the back metal and the bearing alloy layer include various types conventionally used in the field. Can be used under various conditions.

  The bearing alloy layer is preferably an aluminum bearing alloy or a copper bearing alloy mainly composed of Al or Cu.

The composition of the aluminum-based bearing alloy is not particularly limited, but is 1 mass% or less of Cr, Si, Mn, Sb, Sr, Fe, Ni, Mo, Ti, W, Zr, V, Cu, Mg, Zn, and the like. An alloy containing one or more elements and one or more elements such as Sn, Pb, In, Tl, Bi and the like of 20% by mass or less can be preferably used.
The former group of elements mainly imparts strength and wear resistance, and the latter group of elements mainly imparts conformability, and exhibits bearing characteristics depending on the type and amount of each additive element.
Further, the resin overlay layer of the present invention can be used in order to improve the wear resistance of a skirt portion of a piston made of a high Si-Al alloy such as AC8A or AC9B, which is an aluminum alloy casting.

The composition of the copper alloy is not particularly limited, but one or more of 25 mass% or less of Pb and Bi, 10 mass% or less of Sn, and 2 mass% or less of P, Ag, In, Ni, Al Etc. can be preferably used.
Among these elements, soft metals such as Pb and Bi exhibit conformability, Sn, which is a basic component of bronze, exhibits strength and wear resistance, and other components supplementarily improve characteristics. In particular, P is effective for deoxygenation, sintering promotion, strengthening, etc., Ag is a compound effective for improving sliding characteristics, formed by reaction with an impurity component S in lubricating oil or copper, and In is corrosion resistant. The wettability of the lubricating oil is improved, and Ni and Al have effects such as strengthening copper.

  The bearing alloy layer generally has a thickness of 0.1 mm to 0.5 mm. The backing steel for reinforcing this is generally 1.0 mm to 3.0 mm in thickness.

Then, the method to manufacture the half bearing which concerns on this invention is demonstrated.
The half bearing can be manufactured through the following steps.
(A) Solid lubricant (A) and binder resin containing solid lubricant (a) having cleavage on a half bearing base material having a back metal and a bearing alloy layer disposed on the back metal Applying a resin overlay layer comprising:
(B) a step of drying with the coating surface of the bearing central portion of the resin overlay layer facing downward;
(C) A step of firing.

Although the resin overlay layer includes a solid lubricant (A) and a binder resin containing a solid lubricant (a) having a cleavage can exemplified MoS ₂ in a solid lubricant (a) having a cleavage, the MoS ₂ 1 It may be used in seeds or in combination with other solid lubricants. In general, it is preferable that the solid lubricant material has an aspect ratio (a value obtained by dividing the square root of the flake area by the thickness) of 10 or more from the viewpoint of low friction.
30-50% by volume of the solid lubricant (A) containing the solid lubricant (a) having cleavage is mixed with the remaining binder resin, and a diluent is added to prepare a paint. In this coating material, the solid content is preferably about 10 to 50%. When the solid content is smaller, the mutual contact of the solid lubricant particles is reduced, and the tendency to arrange them in parallel as shown in FIG. 3 becomes stronger.
Here, the solid content represents a mixture of the binder resin and the solid lubricant (A), and the paint represents a mixture of the solid content and the diluent.

When MoS ₂ is used as the solid lubricant (a) having cleavage, the solid lubricant that can be combined with MoS ₂ includes hexagonal boron nitride (h-BN), graphite as the solid lubricant having cleavage. , WS ₂ . Further, polytetrafluoroethylene (PTFE) having no cleavage may be used in combination.
The solid lubricant (A) may be used alone or in combination with other solid lubricants as long as the solid lubricant (a) having cleavage is included.
Among the solid lubricants (a), MoS ₂ is preferable from the viewpoint of lipophilicity with the lubricating oil. When using a combination of MoS ₂ and other solid lubricants, at least one of PTFE and graphite can be used, which is superior in lubrication performance to MoS ₂ especially when the lubricating oil is insufficient. Indicates. If further addition of graphite to the MoS ₂ as a solid lubricant, MoS ₂ solid lubricant (a) the overall relative 40 vol% or more, less than 100 vol%, from the viewpoint of ensuring the orientation of the MoS ₂ Preferably, when the solid lubricant (A) further contains PTFE, the ratio of the solid lubricant (a) having cleavage in the solid lubricant (A) is 40% by volume or more and less than 100% by volume. preferable.

  The binder resin is a thermosetting resin such as polyimide resin (PI), polyamideimide resin (PAI), epoxy resin or phenol resin, or thermoplastic such as polybenzimidazole resin (PBI) or polyether ether ketone resin (PEEK). Resin can be used. Among these, PI, PAI, and PBI are preferable from the viewpoint of heat resistance and strength.

  The layer containing the solid lubricant (A) including the solid lubricant (a) having cleavage and the binder resin is referred to as a resin overlay layer, and the solid lubricant (A) in the resin overlay layer is 30 to 50% by volume. It is preferable from the viewpoint of ensuring the orientation of the solid lubricant.

  Further, the thickness of the resin overlay layer is preferably 1 to 20 μm, and more preferably 3 to 10 μm. The thickness of the layer is considered to affect not only the orientation of the solid lubricant particles but also the adhesive strength with the base material, the strength within the layer, the thermal conductivity, and the like.

When the resin overlay layer is coated on the bearing substrate, a diluent is used for uniform dispersion of the solid lubricant and the binder resin. A resin overlay layer is formed by applying a solid lubricant and binder resin (paint) dispersed in a diluent to the bearing, and then removing the diluent and baking.
Although it does not restrict | limit especially as a diluent, N-methylpyrrolidone (NMP) is used preferably.
Moreover, the compounding ratio of a diluent should just be 50-90 volume% of a coating material.

When the resin overlay layer is formed on the bearing alloy layer, a coating method may be applied by pad printing, screen printing, air spray, airless spray, electrostatic coating, tumbling, squeeze method, roll method, or the like.
In addition, as common to all film forming methods, when the film thickness is insufficient, the concentration of the solid lubricant and the binder resin in the diluent is not increased, but is repeatedly applied multiple times. The method is preferably used.

In the drying process after applying the resin overlay layer, the solid lubricant particles move while being slightly inclined by gravity.
In the present invention, in order to change the direction of the cleaved surface of the solid lubricant (a) having cleavage at the center portion and the both end portions of the half bearing, the coating of the center portion of the bearing is applied after coating the resin overlay layer. Dry at 20-40 ° C. with the face down. As shown in FIG. 6 (a), by drying the application surface of the bearing central portion that becomes the resin overlay layer downward, the central portion of the half bearing is solid lubricant (a) with respect to the sliding surface. The cleaved surface is non-parallel (FIG. 6B), and the cleaved surface of the solid lubricant (a) is parallel to the sliding surface at both ends (FIG. 6C).
When drying with the application surface at the center of the bearing facing downward, the form is not particularly limited, such as drying by standing on a drying stand or drying in a form suspended in the air.

It is considered that the direction of the cleaved surface of the solid lubricant (a) at both ends of the bearing is parallel because the direction of the cleaved surface of the solid lubricant (a) is aligned according to gravity when drying. .
Parallel / non-parallel here means that when the solid lubricant (a) is MoS ₂ , as represented by the above formula (1) in the X-ray diffraction pattern, (002), (004), ( 008) planes (relative c-axis intensity ratio and c-axis orientation ratio) can be distinguished by 85% or more / less than.

  In the firing step, the half bearing base material on which the resin overlay layer has been applied and dried may be gradually heated to the firing temperature of the resin and fired at 100 to 300 ° C. for 1 hour in the air.

  Although the back metal is provided to improve the bearing strength, various types of conventional back metal can be used under various conditions. The preferable thickness of the back metal is 1.0 mm to 3.0 mm.

  The bearing alloy layer is preferably an aluminum bearing alloy or a copper bearing alloy mainly composed of Al or Cu. Moreover, the preferable thickness of a bearing alloy layer is 0.1 mm-0.5 mm.

EXAMPLES The present invention will be specifically described below with reference to examples. However, the present invention is not limited to these examples.
(Production of half bearing)
SPCC (JIS) is used for the back metal, and an aluminum half bearing alloy (Al-11.5% Sn-1.8% Pb-1.0% Cu-3.0% Si-0.3% Cr) Was pressed. The resin overlay layer precursor solution was applied onto the aluminum half bearing alloy by the roll method or air spray method, and was allowed to stand on the table and dried so that the coating surface at the center of the bearing would be downward. . Drying was performed at room temperature for 1 hour. Then, the half bearing covered with the resin overlay layer was produced by baking at 250 degreeC for 1 hour in air | atmosphere.
The applied resin overlay precursor solution comprises a solid lubricant, a diluent, and a binder resin. The composition of the solid lubricant and the binder resin are as shown in Table 1. The diluent is N-methylpyrrolidone (NMP), and the ratio of each is solid lubricant: diluent: binder resin = 35: 50: 15 (volume%).
The thickness of the resin overlay layer is shown in Table 1. These were measured by observing and analyzing the image of the cross section of the test piece with SEM.

  After the resin overlay precursor solution was applied in the same manner as described above, a half bearing that was fired in the same manner as described above was used as a comparative example.

(X-ray diffraction measurement -XRD-)
XRD measurement was performed using MiniFlex II manufactured by Rigaku Corporation. The radiation source was CuKα, 40 kV-100 mA, and the measurement range was 10 ° ≦ 2θ ≦ 64 °.
The sample was cut into a 1 cm × 1 cm test piece by cutting a half bearing coated with a resin overlay, and the measurement was performed at the center and the end of the bearing.
From the obtained diffraction pattern, the relative c-axis intensity ratio (c-axis orientation ratio) was calculated by the formula (1). Table 2 shows the orientation ratios at the center and end of the bearing.

(Measurement of wear at the bearing center and bearing ends)
In order to measure the amount of wear at each of the bearing central portion and the end portion, a wear test was performed using a bearing wear tester under the following conditions.
Rotational speed: 0 rpm (1 minute hold) → 1200 rpm (1 minute hold) → 0 rpm (1 minute hold) cycle test Lubricating oil: 0W-20
Lubrication temperature: 100 ° C
Load: 4.41kN
Test time: 100 hours After the abrasion test, the film thickness of the resin overlay layer before and after the abrasion test of the test piece coated with the resin overlay layer is measured by image analysis using a scanning electron microscope (SEM) Was defined as the amount of wear. The results are shown in Table 2.

From Table 1 and Table 2, the bearing surface of the resin overlay layer in the center portion of the bearing is dried and dried, so that the orientation ratio of the solid lubricant bearing center portion is less than 85% non-parallel, and the end portion is 85% or more. It can be seen that there is a difference in the alignment and orientation. It was found that by reducing the orientation ratio of the central portion while maintaining the orientation ratio of the end portion, the wear amount of the central portion was reduced and the wear resistance was improved.
Moreover, since the orientation rate of the solid lubricant at the bearing end is maintained, it is considered that low friction is realized and conformability is ensured.

  The present invention provides a half bearing having both contradictory characteristics such as conformability and wear resistance by making the orientation of the solid lubricant different at both ends and the center of the half bearing. It is. Since the central part and the two end parts have different characteristics, the role as a bearing can be shared, so it can be used as a slide bearing for engines for high-performance automobiles such as start / stop engines and other industrial machines. The possibility of being adopted is great.

10 Hexagonal flaky solid lubricant 12 Resin overlay layer 101 Back metal 102 Bearing alloy layer 103 Resin overlay layer 110 Solid lubricant (MoS ₂ )
A Center part in the circumferential direction B End part in the circumferential direction

Claims (10)

  A half bearing in which a resin overlay layer containing a binder resin and a solid lubricant (A) is provided on a half bearing base material having a backing metal and a bearing alloy layer disposed on the backing steel. The solid lubricant (A) contains a solid lubricant (a) having a cleavage, and the direction of the cleavage surface of the solid lubricant (a) is the circumferential ends of the half bearing and the circumferential center. Different half bearings.   The angle between the cleaved surface and the sliding surface of the solid lubricant (a) at both circumferential ends of the half bearing is such that the cleaved surface of the solid lubricant (a) at the circumferential center of the half bearing. The half bearing according to claim 1, wherein the half bearing is smaller than an angle formed with the sliding surface.   The cleavage surface of the solid lubricant (a) is parallel to the sliding surface at both circumferential ends of the half bearing, and is not parallel to the sliding surface at the circumferential center of the half bearing. The half bearing according to claim 1 or 2. The solid lubricant (a) is, half bearing according to claim 1 which is MoS _2.   The half bearing according to any one of claims 1 to 4, wherein a thickness of the resin overlay layer is 3 to 10 µm.   The half bearing according to any one of claims 1 to 5, wherein the binder resin is one or more resins selected from the group consisting of a polyamideimide resin, a polyimide resin, and a polybenzimidazole resin.   The half bearing according to any one of claims 1 to 6, wherein the solid lubricant (A) is 30 to 50% by volume in the resin overlay layer. Wherein the solid lubricant is (a), further comprising a graphite, entire solid lubricant (a) to, MoS ₂ is less than 40 vol% to 100 vol%, according to any one of claims 1-7 Half bearings.   The solid lubricant (A) contains polytetrafluoroethylene, and the proportion of the solid lubricant (a) in the solid lubricant (A) is 40% by volume or more and less than 100% by volume. The half bearing of any one of -8.   Resin comprising a binder resin and a solid lubricant (A) containing a cleaved solid lubricant (A) on a half bearing base material having a back metal and a bearing alloy layer disposed on the back metal. A method for manufacturing a half bearing, comprising: a step of applying an overlay layer; a step of drying the coating surface of the bearing central portion of the resin overlay layer facing downward; and a step of firing.

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