JPH01303314A - Bearing device - Google Patents

Abstract

PURPOSE:To improve the fatigue property in the subject bearing device having a sliding bearing by joining a bearing layer to a back metal made of a material with an elastic modulus lowered under cold working, through cold rolling. CONSTITUTION:The large end part 4 of a connecting body in an internal combustion engine, with a sliding bearing 8 arranged between the half part 5 of the large end part and a bearing cap 6, is fastened with a bolt 7. The sliding bearing 8 is formed by joining a bearing alloy layer 10 made of aluminum alloy or the like and a material with an elastic modulus lowered under cold working, for example, a back metal made of austenite stainless through cold rolling to each other. In this case, the elastic modulus of the back metal 9 is smaller on the inner side than the outer side. Accordingly, the back metal preferably followes the heat expansion deformation of bearing housings 5, 6, each having a large heat expansion factor and the absolute value of stress variation quantity and the stress caused on the outer layer of the back metal 9 is smaller than that of conventional one. Thus, it is possible to improve the fatigue property.

Description

Detailed Description of the Invention The present invention relates to a bearing device having a flat bearing consisting of a laminated body of a bearing layer and a backing metal supporting the bearing layer, and in particular, to a bearing device having a flat bearing made of a laminated body of a bearing layer and a backing metal supporting the bearing layer. It is a half-split type that is inserted with a predetermined interference between the bearing housing of the type that connects the bearing housing and the rotating bearing housing that is the supported body. The present invention relates to a bearing device that is a suno flat III bearing and is composed of a laminate of a bearing layer and a backing metal that supports the bearing layer.

mIJL In an internal combustion engine, the piston and crankshaft are i'l!
Both ends (small end 1 and large end) of the connecting link 1 are connected to a piston pin and a crankshaft (crank pin), respectively.
It forms the bearing housing of the bearing device that supports the.

The small end forms an integral bearing housing with a through hole into which a flat bearing supporting the piston pin is press fit. The big end forms a bearing housing of the type that joins the two halves using Pol 1 ~, and within this bearing housing ? 1' A cropped plain bearing is fitted with a predetermined interference (talllash height skewer).

By the way, connecting rods are increasingly being made of aluminum alloy in order to increase the output, speed, and weight of engines. However, if the aluminum alloy bearing housing (narrow width part and large end of the aluminum alloy connecting rod)
Its coefficient of thermal expansion (approximately 23x+oe) is almost twice that of a bearing made of ordinary steel (approximately 12x10-6)! Therefore, it is necessary to compensate for the difference in thermal expansion between the bearing housing and the bearing due to the rise in temperature, and various measures have been taken.

An example of this is shown in Japanese Utility Model Publication No. 56-4021, in which a bushing made of iron-based gold (for example, austenitic stainless steel) with a coefficient of thermal expansion that is the same or similar to that of the aluminum alloy is attached to the small end of an aluminum alloy fFJ connecting rod. Steel bushings) are press-fitted. In this example, the coefficient of thermal expansion of the A-stenitic stainless steel bushing (approximately 18X 10
) is considerably larger than that of ordinary steel, and is close to the coefficient of thermal expansion of aluminum alloy, so even if the tightness of the bushing at the small end of the bearing housing is smaller than that of a bushing made of ordinary steel. (In other words, even if the stress is reduced when tightening the bearing housing), the ability of the bushing to follow the thermal expansion deformation of the small end portion can be ensured.

However, the aluminum alloy small end Ji and A-
When a bushing made of stenoitic stainless steel fA expands and deforms, the clearance between the bushing and the gate-through steel shaft may increase, and austenitic stainless steel has poor thermal conductivity (11) compared to ordinary steel. Therefore, the heat transfer between the shaft and the small end is smooth, but there is a drawback that it is rough.

The idea disclosed in the above-mentioned Japanese Utility Model Publication No. 56-4021 is applied to a bearing housing formed by connecting two aluminum alloy halves using a common steel bolt like the large end of a connecting rod, Assume that a cylindrical bushing made of austenitic stainless steel is inserted between a shaft made of steel and a bearing housing. When the temperature rises, the thermal expansion of each half of the bearing housing is suppressed by the bolt in the axial direction of the bolt, and is suppressed in the direction perpendicular to the bolt axis, so that as a result, the bearing housing Transforms into a horizontally long image. At this time, since the bushing is cylindrical, it has poor ability to follow the bearing housing that deforms into a horizontally elongated shape, and an increased clearance may occur between the bearing housing and the bushing at a position near the bolt.

In the case of a bearing housing made by joining two halves 6'i together using bolts, as described above, insert a half-split JXll flat bearing into the bearing housing with a predetermined tightening interference of 6'i.
When the bearing housing is fitted, the bearing housing deforms to follow the horizontally elongated deformation of the bearing housing. However, since the flat bearing repeatedly deforms between a right circular shape and an oblong shape due to temperature changes, the flat bearing is required to have good fatigue characteristics.

For example, as shown in Japanese Patent Application Laid-Open No. 5G-13407, white metal, kelmet metal,
Bearings made of laminated metal with a layer of bearing alloy such as aluminum alloy are known, but even such flat bearings have the above-mentioned problems, especially with respect to the steel back metal.

Accordingly, the present invention improves the deformability of the vehicle bearing to follow thermal expansion deformation of the bearing housing in the bearing layer r on the right side of the vehicle bearing, which is composed of a laminated body of a bearing layer and a back metal supporting the bearing layer. In addition, the main purpose is to improve fatigue characteristics.

Another object of the present invention is to prevent an increase in the clearance between the rotating shaft and the plain bearing during thermal expansion and deformation in the bearing device.

A further object of the present invention is to improve heat transfer between the rotating shaft and the bearing housing in the bearing device.

In order to achieve the above objects, the bearing '1A' of the present invention is made of a material whose elastic modulus decreases when the back metal of the plain bearing is cold-worked, And it is joined to the bearing layer by cold rolling.

When the backing metal and the bearing layer are overlapped and cold-rolled, the elastic modulus of the backing metal is small on the inside where it contacts the bearing layer, and the elasticity on the outside is small, so the elastic modulus of the backing metal made of the above material is With phase'>fi L/, the elastic modulus on the outside is smaller than the elastic modulus on the inside. Therefore, the flat bearing according to the present invention deforms well following the thermal expansion deformation of the bearing housing, which has a large coefficient of thermal expansion, and furthermore, the stress fluctuation (1) and the absolute value of the stress generated in the outer layer of the backing metal due to thermal expansion deformation are lower than those of the conventional bearing. Since it is smaller than the above, it is possible to aim at improving the fatigue property f1.

Mizumoto who has the following characteristics]! 1" plain bearing
! ? Therefore, it is best to use austenite 1-stainless steel as the backing metal. In other words, in steel types other than A-Stevui 1-series stainless steel, as the cold working rate increases, both hardness and elastic modulus increase; however, in the case of E-Steepy stainless steel, as the cold working rate increases, the working rate increases. Although the hardness increases depending on the amount, the elastic modulus tends to decrease. Therefore, in the case of ausonitic stainless steel Wfi gold, the hardness of the outer layer is large, and the resistance to fretting between the bearing housing and the bearing housing is improved.

In a plain bearing that uses ausbunite stainless steel as the backing metal, it is preferable to form the bearing layer with an alloy phase having a larger coefficient of thermal expansion than A-sudenoi t-stainless steel. It is possible to prevent the clearance between the rotating shaft and the plain bearing from increasing during thermal expansion and deformation.

Furthermore, by cold rolling the back metal to make it substantially thinner, it is possible to improve heat transfer between the rotating shaft and the bearing housing. Note that the expression ``substantially thickening the back metal'' means that the thickness of the back metal is reduced by 30-50%, and the thickness of the crank main cylinder in a 2000cc class passenger car engine is 30% to 50% thinner. While the V of the backing plate made by Nord terminology is about 1.6 mm, the plate thickness is, for example, about 1.1 to 1.2 mm.

Figure 1 shows an exploded view of a connecting rod used in an internal combustion engine. The connecting rod 1 is a member that connects a screw and a crankshaft, and the part into which the piston pin 2 is fitted is a small end 3, and the part connected to the crankshaft (crank pin) is a large end 4. It is called. The large end portion 4 is a bearing housing that includes the crankpin center shaft and is divided into an upper and a lower portion, and the large end half portion 5 and the bearing cap 6 are connected by a steel pole 1-7.7. The bearing housing is formed by doing this. A half-split flat bearing 8 is fitted into the bearing housing with a predetermined interference (crush hide fill).

The above connecting rod 1 has the following five features: high output, high speed, and softness.
16 is made of aluminum alloy. The plain bearing 8 is formed of a laminate of a backing metal 9 made of J, uni, and A-state low-item stainless steel shown in FIG. 2, and a bearing base metal F110 made of an aluminum alloy or the like. When the temperature reaches 1, the large end portion 4 deforms horizontally as shown in FIG. 3 (the deformation is emphasized in the drawing). The reason for this deformation is that the thermal expansion of the aluminum alloy large end 4, which has a large coefficient of thermal expansion, is suppressed in the X direction by the steel mold door 7, which has a small coefficient of thermal expansion. This is because when the big end 4 deforms into the shape J shown in FIG. However, in this case, the plain bearing 8 is required to have good follow-up deformability.

When the flat bearing 8 is assembled into the bearing housing 4 with an appropriate interference, compressive stress is generated in the back metal 9 in the circumferential direction. This compressive stress is larger on the inner circumference side than on the outer circumference side, and the adult stress on the inner circumference is expressed by the following equation.

δmaX ==-δ・K (1/E+k> =11)
(However, k is a coefficient determined by the bearing housing, is a constant, F is the elastic modulus of !7! gold, and δ is the interference margin.) Now, assuming that the back metal of the plain bearing is made by Nishitoshi Steel, this This is a poem that incorporates a plain bearing into a bearing housing made of full miniram alloy with a predetermined interference! Gold inner circumference 113J:
The initial stress (σ) and strain (ε) on the GJ and the outer circumference are respectively σ1 (inner), ε1 (inner), σ1 (outer), ε1
(outside), and when the temperature rises and the bearing housing and plain bearing undergo thermal expansion and deformation as shown in Figure 3, the stress and strain of J3 GJ on the inner and outer circumferences are σ2 (inner) and ε2, respectively. (inside), σ2 (outside), and ε2 (outside). These are the stress-strain diagram of the back metal forming material (common steel) (
Figure 6 shows the elastic range (elastic range).
(Differences in stress and strain at the outer periphery are emphasized and shown in a large size). Stresses σI (inside), σ1 (outside) and strains ε1, (inside) and ε1 (outside) [, 1 are large, but humidity and aluminum alloy: the cumulative bearing housing is very heated Vl, When the tension deforms, the tightening against the backing metal is reduced; the HJ force is reduced and a portion of the strain is released, and the stress and strain become smaller than the initial state, resulting in σ2 (inner) and σ2, respectively.
(outside) J3 and ε2 (inside), ε2 (outside).

At this time, the following relationship exists between the amount of change in strain J on the inner and outer peripheries.

ε1 (inside) - ε2 (inside) ε1 (outside) - ε2 (outside)... (2) In other words, the release of strain on the outer circumference is stronger than on the inner circumference. This is due to the following reasons. FIG. 4 shows the butt I! of the half-split flat bearing 8 assembled in the aluminum alloy housing in the initial state. When the a-bearing housing showing the end A is thermally expanded and deformed into a horizontally elongated shape as described above, the flat bearing 8.8 is followed by deformation. At this time, the inner layer B of the back metal 9 is deformed (elastic f
L deformation), and as shown in FIG. 6, the butt end A of the flat bearing 8.8 becomes shaped to protrude outward. Therefore, as expressed by the second equation above, the strain release R in the outer layer of the back metal 9 becomes larger than the strain release R in the inner layer by 1,
A large strain release layer 43 in the outer layer means that the back metal 9 follows the bearing housing well. Since strain and stress have a certain relationship, the second
The formula means that depending on the humidity, the stress difference between the inner and outer parts of the back metal will change as shown in the third formula below.
In other words, the fact that the stress difference increases due to humidity in the elastic region means that the cover 9 follows the bearing housing well.

σ, (inside) - σ1 (outside) <σ2 (inside) - σ2 (outside)... (3) The above is a story about the back metal made of ordinary steel, however,
In the plain bearing 8 of the present invention, the back metal 9 is made of A-stenite stainless steel. As can be seen from Figure 10, fg
In passing steel, when the cold opening rate increases (yield, elasticity lf
However, as the cold working rate increases in ausdepit stainless steel, although the hardness increases and decreases in accordance with the working rate, the elastic modulus tends to decrease. Therefore, when an A-stenoid stainless steel plate and a bearing alloy plate with a smaller hardness than the steel plate are rolled together by u'CIT, the processing rate will be reduced on the joint surface side of the austenoid stainless steel plate. is small and the machining rate is large on the non-bonded surface side, so the elastic modulus is small and the hardness is small on the bonded surface side, and the elastic modulus is small and hardness is large on the non-bonded surface side (the relationship between the sizes is relative) becomes. FIG. 7 shows the stress-strain characteristics (elastic range) of such a backing metal. The straight line ■ represents the characteristics of the inner layer of the backing metal,
The straight line ■ indicates the characteristics of the outer layer of the backing metal. Here, among the hidden funds,
The stress J〉 on the outer periphery is denoted by the symbol * for σ and ε, respectively *σI (inside), *ε1 (inside), *σ1
(outside), F1:ε1 (outside), *σ2 (inside), *ε2
(inner), : are represented by σ2 (outer) and *ε2 (outer), and in the initial state (subscript 1) and at the upper temperature (subscript 2), each σ and ε are as shown in the figure.

Now, the elastic modulus of the inner periphery of this Austety 1~ series stainless steel is equal to the elastic modulus of the ordinary m back metal shown in Fig. 6, and the dimensional relationship between the aluminum alloy bearing housing and the plain bearing. Assuming that the temperature in the initial state and the temperature after the upper temperature limit are the same as in the case of the ordinary steel back metal explained with reference to Fig. 4, the formula *ε1 (inside) - ε1 (inside) *ε2 (Inside) - ε2 (Inside) *ε1 (Outside) - εI (Outside) *ε2 (Outside) - ε2 (Outside) Nido σ1 (Inside) - σ1 (Inside) *σ2 (Inside) - σ2 (Inside) is established. do. Therefore, like the second equation above, equation 41 is established,
Good followability can be obtained.

On the other hand, regarding the stress in the outer layer, *σ1 (outside) < a, (outside) *σ2 (outside) σ2 (outside) Nido σ1 (outside) -:? σ2 (outside) 〈σI (outside) - σ2 (outside) In the case of austepite stainless steel 111J backing metal J3, the absolute stress value and stress fluctuation amount of the outer layer are compared to the case of Nitsu Steel brocade metal. It is understood that the objective is to improve the fatigue properties due to small changes in temperature and to improve the fatigue properties.

In order to obtain a plain bearing in which the elastic modulus differs between the inner layer side and the outer layer side as described above, it is appropriate to use the following manufacturing method.

The dimensions of the manufactured T culm are shown in Figure 8. [l- Two types of rolled material strips, 1 rope '3' FDL receiving alloy (e.g., aluminum alloy) strip 21 and A- Sudenite stainless steel strip 22 are cleaned and roughened. After treatment (roughening of the surface of the strip plate 22), both are cold-rolled by rolls 23 in a mutually overlapping state, and the strip plate 21 is integrally attached to the entrance surface of the strip plate 22. By this cold rolling process, the strip plate 22
Although it is work hardened, the bearing base metal strip 2 is softer than steel.
The side in contact with the roll 23 is processed to a lower degree than the side in direct contact with the roll 23, and the desired hardness difference and elastic modulus difference (
9 can be done.

Laminated strip 24 obtained by pressing both strips 21 and 22
is made into a small piece 25 by cutting, then bending, +
i + finishing and removing processing, sleeve hole processing, claw extension 111- processing, oil sump processing, height finishing processing, meat jwa fL, 1-
After going through processes such as tying, plating, etc., it becomes a half-split flat l1I
h-receiver/E].

Further, as shown in FIG. 9, the small piece 25 after cutting 17i is bent into a cylindrical shape, and then subjected to the steps of width finishing (chamfering, shaping), plating, and thickness finishing 19, and then flattened into a rolled bush shape. A bearing 26 can also be obtained. 271 shows the mating position of the horizontal wound bush type flat bearing 26 (.

FIG. 10 is a schematic view similar to FIG. 2 showing the large end of the connecting rod having this wound bush type flat bearing, and the same parts as in FIG. 2 are given the same reference numerals.

In the obtained plain bearing 8.26, the outer layer side of the Austety 1 stainless steel backing metal has a low hardness and a low elastic V1 coefficient, whereas the inner layer side (the side in contact with the bearing alloy layer) has a low hardness and a low elastic modulus. It's a person. The point is that the elastic modulus of concave steel (
E) decreases as the rolling reduction rate increases, whereas that of austite stainless steel decreases as the rolling reduction rate increases (see Figure 11. Both stainless steel and stainless steel are rolled (the rate increases with the rate).Therefore, the aluminum alloy is assembled with steel bolts. When the bearing housing is thermally expanded and deformed due to the upper temperature limit while supporting the manufactured shaft, it will easily follow the deformation of the ψ bearing 8, 264 bearing housing as described above, and the amount of stress fluctuation generated on the outer layer side of the backing metal due to thermal expansion deformation. Since the absolute stress value is smaller than that of the conventional one, it is possible to improve the fatigue properties.

Another advantage of using ausminitic stainless steel as the material for the back metal in plain bearings 8.26 is that the coefficient of thermal expansion of ausminitic stainless steel (approximately 18
The flat bearing 8.26 is incorporated into a bearing housing made of a material with a large coefficient of thermal expansion such as aluminum alloy, whose coefficient of thermal expansion (10') is considerably higher than that of Katsuotsu steel (approximately 12xlO'). In this case, it is better not to make the interference of the plain bearing 8.26 so large due to the large thermal expansion of the bearing housing. ). In order to make the tightening allowance more compact, the wall thickness of the bearing housing must be increased accordingly to make the stiffness f1 more compact, so we decided to use both the above-mentioned J and A-stenitic stainless steels. It is possible to reduce the weight of the bearing housing and save 11 times.

In addition, the fact that the coefficient of thermal expansion of the A-stencil stainless steel back metal is close to that of the aluminum alloy bearing housing (approximately 23 x 10-8) means that the difference in thermal expansion between the bearing housing and the plain bearing is Therefore, it is preferable that the plain bearing has the ability to cope with thermal expansion of the bearing housing due to temperature rise.

The backing plate 9 is made of a noidal stainless steel with a low coefficient of thermal expansion.
CI' deforms to closely follow the thermal expansion deformation of the aluminum alloy bearing housing, and normally if the coefficient of thermal expansion is small, the clearance between the standard rotating shaft 11 and the plain bearing 8°26 will increase. Where there is a tendency, the bearing base metal h''
? Since i10 is made of austenitic stainless steel J or a material with a low coefficient of thermal expansion (aluminum alloy), the increase in the clearance is suppressed and the occurrence of bumps due to the rotation of the rotary sleeve 11 is prevented. Gusaru.

Since the backing plate 9 made of A-staite stainless steel is made sufficiently thin by cold rolling T, the disadvantage of A-staite stainless steel, which has poor heat conductivity (7), is compensated for.
Heat transfer between the rotating shaft 11 and the bearing housing 5.6 is conventional.

When the ausbunite stainless steel WA back metal 9 is subjected to cold rolling processing, the hardness of its outer layer increases (No. 11).
(see figure), and has good fretting resistance in the contact relationship with the bearing housing. The decrease in toughness due to the increase in (ii! degree) on the outer layer side is compensated by the inner layer side, which has a relatively low hardness.

1. As is clear from the above explanation, this is a bearing device that uses a flat bearing made of a laminate of a bearing layer and a backing metal that supports it, and the backing metal has a modulus of elasticity due to cold working. The bearing layer and the backing metal are made of a material whose C
A bearing device has been proposed which is characterized by being joined in a U-shape.

The processing rate of the backing metal in 1;), in which the backing metal and the bearing layer are overlapped and cold-rolled, is small on the inside in contact with the bearing layer and large on the outside, so the cIF coating rate of the backing metal made of the above material is The difference is that the elastic modulus on the outside is smaller than the elastic modulus on the inside. Therefore, the plain bearing according to the present invention deforms well following the thermal expansion deformation of the bearing housing, which has a large coefficient of thermal expansion, and the stress fluctuations generated in the outer layer of the backing metal due to the thermal expansion deformation: n ilj and the absolute value of the stress are Since it is smaller than the conventional latch, it is designed to improve fatigue characteristics.

In order to build a plain bearing with the above characteristics of 0, it is optimal to use austenitic stainless steel as the back metal, and with austenitic stainless steel, the elastic modulus decreases as the cold opening rate increases. The hardness increases dramatically, so Austety 1 to 11 stainless steel! 'N
In the 43rd attempt, the outer layer must be removed to prevent fretting (seizure wear) between the outer layer and the bearing housing.
Characteristics also improve.

Plain bearings that use austenitic stainless steel as the backing metal. If the bearing layer is made of an alloy material that has a higher thermal expansion than austenitic stainless steel, it is possible to prevent rotational inertia and flat bearings that undergo TJ during thermal expansion and deformation. It is important to prevent an increase in the clearance between the parts.

Furthermore, by cold-rolling the shaft to make it substantially thinner, it is possible to improve the heat transfer properties of Ii+1·11λ1 and the bearing housing G11.

4. Drawing (7) I! vi! ICE Explanation Fig. 1 shows a connecting rod for an internal combustion engine to which the present invention is applied; 1 is an exploded perspective view; Fig. 2 is a schematic view without showing the large end (+fill receiving device) of the connecting rod; Fig. 3; FIG. 4 is a partially enlarged view of FIG. 2, FIG. 5 is a partially enlarged view of FIG. 3, and FIG. A graph showing the deformation characteristics of a common steel plain bearing in comparison with the deformation characteristics of a plain bearing. FIG. 7 is a graph showing the deformation characteristics of the plain bearing of the present invention. FIG. Drawings showing the manufacturing process of a plain bearing; FIG. 9 shows the yJ33-[culm of the rolled bush type plain bearing according to the present invention; FIG. 10 shows the large end of the connecting rod on the right side of the rolled bush type plain bearing. FIG. 11 is a schematic diagram similar to FIG. 2, and is a graph showing the relationship between rolling reduction and physical properties of austenitic stainless steel.

DESCRIPTION OF SYMBOLS 1... Connecting rod, 2... Piston pin, 3... Small end, 4... Large end, 5... Large end half, 6... Bearing kit/tube, 7 ...To pole 1, 8...Flat bearing, 9.
...'A combination, 10... bearing layer, 21, 22... band plate, 23... [coal, 24... laminated band plate, 25...
・Small piece, 26... Rolled bush type flat book receiver, 27...
A" joint position.

Claims (7)

[Claims] (1) A bearing device having a flat bearing consisting of a laminated body of a bearing layer and a back metal supporting the bearing layer, wherein the back metal is made of a material whose elastic modulus decreases by cold working, and the bearing layer and the back metal A bearing device characterized in that these are joined to each other by cold rolling. (2) The bearing device according to claim 1, wherein the elastic modulus of the inner side of the back metal in contact with the bearing layer is higher than the elastic modulus of the outer side. (3) The bearing device according to claim 2, wherein the outer side of the back metal has a higher hardness than the inner side. (4) A bearing housing that engages two halves using bolts, and a half-split type or rolled bush that is inserted with a predetermined tightness between the rotating shaft, which is a supported body, and the bearing housing. type plain bearing, which is composed of a laminate of a bearing layer and a backing metal supporting the bearing layer, and the coefficient of thermal expansion of the bearing housing is larger than each of the coefficients of thermal expansion of the backing metal, the bolt, and the rotating shaft. The bearing device according to claim 3. (5) The bearing device according to any one of claims 1 to 4, wherein the back metal is made of austenitic stainless steel. (6) The bearing device according to claim 5, wherein the bearing layer is made of an alloy material having a larger coefficient of thermal expansion than austenitic stainless steel. (7) The bearing device according to claim 5, wherein the back metal is substantially thinned by cold rolling.