JP2535105B2 - Sliding bearing with composite plating film - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slide bearing for an internal combustion engine, and more particularly to a slide bearing suitable for a high speed / heavy load engine in response to a demand for increasing the output of the internal combustion engine in recent years.

[0002]

2. Description of the Related Art Slide bearings used in internal combustion engines and the like are
Usually, a bimetal in which a copper alloy or an aluminum alloy for a bearing is bonded onto a steel plate is processed into a cylindrical bush or a half-metal shape, and the bearing alloy side is coated with a lead alloy plating film. Here, the main function of the lead alloy plating layer is to improve the compatibility between the bearing and the shaft such as the crankshaft, and to bury foreign matter mixed in the lubricating oil in the lead alloy plating layer, especially the copper bearing. For the alloy, it is possible to protect it from organic acids generated by deterioration of the lubricating oil. For this purpose, lead alloy plating has been described in U.S. Pat. No. 2,605,149, U.S. Pat. No. 3,180,008, Japanese Patent Publication No. 39-2249.
As seen in the disclosure of Japanese Patent No. 8 etc., Sn, Cu,
Slide bearings having lead alloy plating layers with various amounts of added alloy components such as In have been proposed, manufactured, and used.

[0003]

However, in recent automobile engines, bearings are used under high speed rotation and high load in order to achieve higher output and lower fuel consumption. Abrasion progresses rapidly, and there are various problems such as seizure due to abrasion of the plating layer, or even if seizure does not occur, metal tapping noise occurs due to an increase in oil clearance between the shaft and the bearing. Even under heavy load operation in a diesel engine for trucks, after the wear of the lead alloy plating layer, it is highlighted as a problem of corrosion and seizure of the copper alloy layer for bearings. Although there is a demand for a lead alloy plating layer with excellent wear resistance,
Even if various combinations of the components in the lead alloy are changed, it is difficult to obtain wear resistance sufficiently satisfying the requirements.

In response to such a demand, a lead alloy plating layer containing various kinds of inorganic particles has been proposed, but the surface roughness becomes coarse only by simply dispersing the inorganic particles in the lead alloy plating layer. Therefore, when the internal combustion engine is started, the frictional force when the shaft and the bearing come into direct contact with each other becomes large, resulting in a failure of smooth engine operation. Further, even after the good familiarity is obtained by the long-time running-in operation, even if the operation is started, the oil film pressure that changes with the progress of time is local to the coarse inorganic particles in the lead alloy plating layer. A concentrated load will be applied. By repeating this load application, the lead alloy plating layer is gradually fatigued starting from the vicinity of the inorganic particles, and as the fatigue progresses, the inorganic particles near the inorganic particles appearing on the sliding surface of the lead alloy plating layer containing the inorganic particles. The fatigued portions gradually become continuous, and the fatigued portions of the lead alloy plating layer fall out as a whole.
Further, even under a load that does not reach fatigue, if the surface roughness is large, the formation of an oil film between the shaft and the bearing of the internal combustion engine is hindered.
High speed rotation and high load operation are difficult, and the applicable range of the lead alloy plating layer containing inorganic particles is limited. The present invention was devised under such a technical background, and a non-seizure resistance and fatigue resistance are not impaired, and the excellent wear resistance of the composite plating film is exhibited. The purpose is to provide a sliding bearing.

[0005]

[Means for Solving the Problem and Its Action] This object is a plain bearing provided with a lead alloy surface layer containing 0.3 to 25% by volume of inorganic particles as an average composition in the layer thickness direction. A composite plating film in which a lead alloy surface layer containing inorganic particles is attached to a bearing body member, the average particle diameter of the inorganic particles is 1.5 μm or less, and the surface roughness of the composite plating film is Rz 4 μm or less. This is achieved by providing a plain bearing having

The plain bearing of the present invention typically comprises a steel backing metal, a bearing copper alloy layer or aluminum alloy layer provided on the backing metal, and a composite plating film provided on the copper alloy layer. It is provided as a laminated body of. The total amount of lead alloy that constitutes the matrix of the composite plating film is 2 to
A material containing 30% by weight of one or more of Sn, In, Sb, Cu and Zn is preferable. It is preferable to interpose an intermediate plating layer having a thickness of 0.5 to 5 μm between the composite plating film and the alloy layer (copper bearing alloy layer or aluminum alloy layer for bearing) which is a lower layer of the composite plating film. And the intermediate plating layer is Ni, Ni alloy,
Co, Co alloy, Fe, Fe alloy, Cu, Cu alloy, A
It is formed of any one kind of metal selected from the group consisting of g and Ag alloys. Further, it is preferable to interpose a joining metal layer for joining both layers between the back metal and the alloy layer (copper alloy layer for bearing or aluminum alloy layer for bearing). Ni alloy, Cu, Cu
It is formed of any one kind of metal selected from the group consisting of alloys, Al and Al alloys.

The inventors of the present invention carried out a sliding test under various conditions on a test piece provided with a composite plating film of a lead alloy substrate containing various inorganic particles, and observing the surface of the composite plating film before and after the test. Analyzed. The results are as follows. There is a positive proportional relationship between the average particle size of various inorganic particles and the surface roughness of the composite plating film formed by co-precipitating the particles in the lead alloy plating layer by the composite plating method. The correlation with the initial friction coefficient at the start of the dynamic test is clearly recognized. The average particle size of the inorganic particles is 1.5μ
m or less, and the surface roughness of the composite plating film surface layer is R
The sliding test piece with a composite plating film of z4 μm or less has a low initial friction coefficient and an oil film is formed smoothly from the start of operation, so the amount of wear at the initial stage of friction is suppressed to a low level and then normal wear shifts. Even after that, due to the action of the inorganic particles contained in the composite plating film, a lead alloy plating layer having extremely excellent wear resistance is obtained, and the sliding bearing for an internal combustion engine can have a long life.

Next, each component, bearing structure, etc. in the present invention
The reason for the limitation will be described. The inorganic material used in the present invention is
Nitride (eg BN, TiN, CuN, etc.), carbide
(For example, SiC, TiC, B_FourC, TaC, etc.) Fluoride
Thing (eg (CF) _n, CaF₂Etc.), sulfides (eg,
For example, MoS₂, WS₂Etc.) and others, especially limited
It is not something to be done.

Regarding the content of the inorganic particles, the average composition in the thickness direction of the composite plating film is 0.3% by volume.
If it is less than 25, the effect of improving wear resistance is small and the average composition is 25.
When the content exceeds the capacity%, the toughness of the composite plating film itself is lost, resulting in lack of fatigue resistance and eventually wear resistance. Therefore, the content of the inorganic particles is limited to 0.3 to 25% by volume as an average composition, and a more preferable average composition is 0.5 to 20% by volume.

With respect to the average particle size of the inorganic particles and the surface roughness of the composite plating film, in the sliding bearing for automobiles, the lead alloy plating layer generally requires a thickness of 10 to 30 μm, and the surface smoothness is at the same time. Required. Here, the thickness of the composite plating film is set to 10 to 30 μm, and in order to obtain a surface having a particularly low initial friction coefficient, the average particle size of the inorganic particles is set to 1.5 μm or less (not including zero) , and The surface roughness of the obtained composite plating film is Rz 4 μm or less (zero
(Not included) is required. The composite plating film obtained by using the inorganic particles having a particle size of more than 1.5 μm is difficult to have a fine surface roughness, and a film having a low initial friction coefficient cannot be obtained. Therefore, the average particle size of the inorganic particles is limited to 1.5 μm or less, and the surface roughness of the composite plating film is limited to Rz 4 μm or less. In addition,
The average particle size of the inorganic particles is more than zero and 1.5 μm or less.
However, considering the actual problems such as manufacturing costs,
In this case, the preferable average particle size is 0.1 μm to 1.5 μm. Ma
Also, regarding the surface roughness, make the roughness zero in reality.
Is not acceptable from a manufacturing cost standpoint, so
The roughness is 0.1 μm to 4 μm. As mentioned above,
In the present specification, zero is included in the average particle size “1.5 μm or less”.
Not rarely, zero is not included in the surface roughness "Rz 4 μm or less"
Yes.

Base metal of plating film Addition metal Sn of lead alloy,
When the total content of In, Sb, Zn and Cu is less than 2% by weight, the mechanical strength such as hardness and tensile strength is low, and the corrosion resistance to organic acid generated when the lubricating oil deteriorates is low. It lacks sex. If the total amount exceeds 30% by weight, the temperature range in which sliding bearings are used is 1
Since the mechanical strength at 00 to 130 ° C is remarkably reduced, Sn, In, S added in the lead alloy plating film
The total content of one or more of b, Zn and Cu is limited to 2 to 30% by weight, and the most preferable total content is 5 to 25% by weight.

[0012]

1 to 8 are schematic views showing the vertical cross-sectional structure of a sliding bearing according to the present invention having a composite plating film as a surface layer. FIG. 1 shows Cu-Pb system, C
On the Cu alloy layer 3 of u-Pb-Sn system, Cu-Zn system, Cu-Sn system, etc., BN, SiC, (CF) _n , Mo.
Including one or two or more selected from inorganic particles, such as _{S 2, Pb-Sn, Pb} -Sn-Cu, Pb-Sn-S
An example is shown in which Pb alloy layers 1 of b, Pb-Sn-Zn, Pb-Sn-In, etc. are stacked. 2 is a low carbon steel,
An example in which a Cu alloy layer 3 and a Pb alloy layer 1 shown in FIG. 1 are laminated on a steel backing 4 made of high carbon steel, stainless steel, special steel or the like is shown. FIG. 3 shows that Ni, Co, Fe and A are provided between the Cu alloy layer 3 and the Pb alloy layer 1 in FIG.
An example in which the intermediate layer 2 made of either g or Cu or an alloy thereof is provided. In FIG. 4, an intermediate layer 2A made of any one of Ni, Co, Fe, Ag, and Cu different from the intermediate layer 2 or an alloy thereof is provided between the intermediate layer 2 and the Cu alloy layer 3 in FIG. In addition, Sn plating film or Pb on the surface of the steel backing 4 for the purpose of rust prevention
An example with a -Sn plating film 7 is shown. Figure 5
An example is shown in which the Pb alloy layer 1 is laminated on the Al alloy layer 5 of Al-Sn type, Al-Si type, Al-Zn type or the like. FIG. 6 shows the Cu alloy layer 3 in FIG.
An example corresponding to the one replaced with is shown. FIG.
Between the steel backing 4 and the Al alloy layer 5, Cu, Ni, Al
Alternatively, the bonding layer 6 made of an alloy thereof is provided, and the intermediate layer 2 is provided between the Al alloy layer 5 and the Pb alloy layer 1.
(Material is as described above). FIG.
6 omits the intermediate layer 2A in the example shown in FIG.
An example in which an Sn plating film or a Pb-Sn plating film 7 is attached to the surface of the steel backing metal 4 for the purpose of rust prevention is shown.

Test Example 1: Copper alloy powder (Cu-2
A sintered layer was provided by sintering 3Pb-3.5Sn) to produce a bimetal. Then, the obtained bimetal was cut, and a Suzuki type friction and wear test piece (hereinafter referred to as a test piece) was manufactured through a machining process. For the test piece,
After pretreatment was performed in the order of ordinary solvent degreasing, electrolytic degreasing, and pickling, the surface of the sintered copper alloy was plated under the following conditions. Plating condition: normal watt Ni plating bath, bath temperature 50
C, cathode current density 6 A / dm ² . An Ni intermediate plating layer having a thickness of 1.5 μm is previously provided on the surface of the copper alloy, and Si having different average particle sizes is used in an ordinary borofluoride lead alloy plating bath.
Using C (carbide) as inorganic particles, 15 to 25 g /
Disperse 1 liter of the SiC in the plating bath to obtain a bath temperature of 2
Electrolysis was performed at 5 ° C. and a cathode current density of 3 to 5 A / dm ² to obtain a composite plating film composed of coprecipitated inorganic particles and a base lead alloy layer. The thickness of each layer is 20μ of composite plating film
m, copper alloy layer 0.3 mm, steel back metal layer 1.2 mm. The particle size, the amount of co-precipitation, and the composition of the lead alloy as the plating film substrate in each test conducted under different conditions are shown in Table 1 (see Sample Nos. 1 and 2. Samples Nos. 3 and 4 are comparative examples). ).

Test Example 2: Using a test piece similar to that of Test Example 1, the same pretreatment (application of a sintered layer as in Example 1) was performed, and Watt Ni plating (Ni intermediate plating) was performed. After that, Si ₃ N ₄ (nitride) each having a different average particle size is used as inorganic particles, and 30 to 50 g / liter thereof is dispersed in a lead alloy plating bath, and a composite plating film is prepared in the same manner as in Test Example 1. Got The thickness of each layer is the same as in Test Example 1, and the particle size, eutectoid amount, and lead alloy plating composition are shown in Table 1 (see Sample Nos. 5 and 6; Sample Nos. 7 and 8).
Is a comparative example).

Test Example 3: For comparison with a conventional product, a test piece similar to that of Test Example 1 was used, which was subjected to a pre-treatment (application of a sintered layer similar to that of Test Example 1) to form inorganic particles. Electrolysis was carried out using a lead alloy plating bath that did not contain it to obtain a surface layer having the composition shown in Table 1. (See sample Nos. 9-11). The thickness of each layer is the same as in Test Example 1.

Test Example 4: A bearing aluminum alloy (Al-6Sn-1Cu-1Ni) thin plate was roll-bonded to a steel backing by a roll rolling method, and then annealed at a temperature of 350 ° C. for 4 hours to produce a bimetal. . Next, the obtained bimetal was cut and machined in the same manner as in Test Example 1 to prepare a test piece. Then, normal solvent degreasing,
Alkali etching, pickling, and zinc displacement treatment, which are generally known pretreatments on Al alloys, are sequentially performed, and then a watt Ni plating bath is used to obtain a bath temperature of 50 ° C. and a cathode current density of 6
Electrolysis is carried out under the condition of A / dm ² , resulting in a thickness of 2.0 μm.
Ni intermediate layer was applied. Then, in the same manner as in Test Example 1, SiC having an average particle size of 1.0 μm was used.
Disperse ~ 50g / l in the plating bath, bath temperature 25
Electrolysis was carried out under the conditions of a temperature of 3 ° C. and a cathode current density of 3 to 5 A / dm ² to coprecipitate the inorganic particles of SiC to obtain a composite plating film. The thickness of each layer is a composite plating film of 20 μm, an aluminum alloy layer of 0.3 mm, and a steel back metal layer of 1.2 mm. The amount of co-precipitation and the composition of the lead alloy plating are shown in Table 1 (Sample No. 1
See 3-15. Sample No. 12 is a comparative example).

Test Example 5: Using a test piece similar to that of Test Example 4 and applying the same pretreatment, using a cyanide copper strike plating bath applied on a conventional Al alloy, a bath temperature of 5
Electrolysis was performed under the conditions of 0 ° C. and cathode current density of 1.5 A / dm ² to form a Cu intermediate layer having a thickness of 2.0 μm, and 50 to 100 g / liter of inorganic particles similar to those of Test Example 4 was placed in the plating bath. And bath temperature 25 ° C, cathode current density 3-5 A / dm
Electrolysis is performed under the condition ²
Was co-precipitated to obtain a composite plating film. The thickness of each layer is the same as in Test Example 4, and the eutectoid amount and the lead alloy plating composition are shown in Table 1 (see Sample No. 16; Sample No. 17).
Is a comparative example).

Test Example 6: A composite plating film obtained by dispersing various inorganic particles in a plating bath in the same manner as in Test Examples 1 to 5 is summarized in Table 1 (Sample N).
o. 18-20). Furthermore, a seizure test and a wear test were carried out to confirm the effect of each sample. The test conditions are shown in Table 2, and the results are shown in FIGS.
Are shown together.

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

As can be seen from the surface roughness of each sample shown in Table 1, when the average particle size of the inorganic particles is 1.5 μm or less, the surface roughness of the composite plating film is Rz 4 μm or less. However, in these samples, the friction coefficient at the time of initial familiarization shown in FIG. 10 is suppressed to be low, and a smooth oil film is formed by this effect, and a high seizure surface pressure can be obtained. Further, if the average particle diameter of the inorganic particles exceeds 1.5 μm, it is difficult to make the surface roughness of the composite plating film Rz 4 μm or less, and the friction coefficient at the initial familiarizing point becomes high (FIG. 10), It is understood that seizure occurs at a relatively low surface pressure. The average particle size of the inorganic particles is 1.
Even if it is 5 μm or less, if the coprecipitation amount exceeds 25% by volume, the surface roughness of the composite plating film exceeds Rz 4 μm, and seizure occurs at a low surface pressure. Further, as can be seen from the abrasion test results shown in FIG. 11, the inorganic particles containing the average particle diameter of 1.5 μm or less in an amount of 0.3 to 25% by volume and having a surface roughness R
The product of the present invention having a composite plating film of z4 μm or less is
Compared to those containing no inorganic particles, and those containing such particles, the amount of wear is reduced as compared with those outside the range of 0.3 to 25% by volume, and it is extremely effective in improving wear resistance. I know that there is. Thus, it is understood that the product of the present invention is a composite plated plain bearing having extremely excellent wear resistance and non-seizure resistance.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a copper alloy layer having a copper alloy layer according to an embodiment of the present invention.
Sectional drawing of the principal part of a layered plain bearing.

FIG. 2 is a waist sectional view of a three-layer structure slide bearing according to one embodiment of the present invention.

FIG. 3 is a view showing a modified example of the bearing shown in FIG.

FIG. 4 is a view showing a modified example of the bearing shown in FIG.

FIG. 5 is a sectional view of a main part of a two-layer structure slide bearing having an aluminum alloy layer according to one embodiment of the present invention.

FIG. 6 is a cross-sectional view of a main part of a five-layer structure slide bearing according to an embodiment of the present invention in which an aluminum alloy layer is provided on a steel back metal.

7 is a diagram showing a modified example of the bearing shown in FIG.

8 is a diagram showing a modified example of the bearing shown in FIG.

FIG. 9 is a bar graph showing the results of a seizure test.

FIG. 10 is a bar graph showing the initial coefficient of friction of each test piece.

FIG. 11 is a bar graph showing the results of wear tests.

[Explanation of symbols]

 1 Pb alloy layer 2 Intermediate layer 2A Intermediate layer 3 Cu alloy layer 4 Steel back metal 5 Al alloy layer 6 Bonding layer 7 Sn plating or Pb-Sn plating film

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshio Fuwa, Toyota-cho, Toyota-cho, Aichi Prefecture Toyota Motor Co., Ltd. (56) Reference JP-A-63-172017 (JP, A) Japanese Patent Publication 2-35020 (JP, B2)

Claims (6)

(57) [Claims] 1. The average composition in the layer thickness direction is 0.3.
In a plain bearing provided with a lead alloy surface layer containing 25% by volume of inorganic particles, a lead alloy surface layer containing inorganic particles is a composite plating film attached to a bearing body member, and the average particle size of the inorganic particles is 1.5μm or less (including zero
No. ) , the surface roughness of the composite plating film is Rz 4 μm or less (Ze
Sliding bearing having a composite coating, characterized in that b is not including). 2. The total amount of the lead alloy is 2 to 30% by weight.
2. A plain bearing having a composite plating film according to claim 1, which contains one or more of Sn, In, Sb, Cu and Zn. 3. A steel backing, a bearing copper alloy layer provided on the backing, and a composite plating film provided on the copper alloy layer, which is formed as a laminate.
A plain bearing having the composite plating film described in 1. 4. A laminated body of a steel backing metal, a bearing aluminum alloy layer provided on the backing metal, and a composite plating film provided on the aluminum alloy layer. A plain bearing having the described composite plating film. 5. An intermediate plating layer having a thickness of 0.5 to 5 μm is present between the composite plating film and the alloy layer which is a lower layer of the composite plating film, and the intermediate plating layer is N
i, Ni alloy, Co, Co alloy, Fe, Fe alloy, C
A slide bearing having a composite plating film according to claim 3 or 4, which is formed of any one kind of metal selected from the group consisting of u, Cu alloy, Ag and Ag alloy. 6. A joining metal layer for joining both layers is present between the back metal and the alloy layer, and the joining metal layer is Ni, Ni alloy, Cu, Cu alloy, Al and Al alloy. A slide bearing having a composite plating film according to any one of claims 3, 4, and 5, which is formed of one kind of metal selected from the group consisting of: