JP5429026B2 - Radial slide bearing and rotating shaft bearing structure - Google Patents

Description

  The present invention relates to a bearing structure for a radial slide bearing and a rotary shaft, and more particularly, a radial slide bearing having a halved structure in which a lining layer is formed on the inner peripheral side of a back metal and the rotary shaft is supported by a lining layer via lubricating oil. Further, the present invention relates to a bearing structure of a rotating shaft that supports the rotating shaft with a radial slide bearing through lubricating oil.

  The related art of the bearing structure which supports a rotating shaft via lubricating oil is disclosed in the following Patent Documents 1 and 2. In the plain bearing of Patent Document 1, the bearing metal is curved so that the thickness of both end portions in the axial direction of the bearing metal is thicker than the thickness of the center portion, and many circumferential groove grooves are formed on the surface of the bearing metal. Provided. As a result, a high oil film pressure is maintained over the entire bearing area of the slide bearing, and the lubrication performance of the bearing is improved and the bearing sound is reduced.

  Further, in the bearing structure of Patent Document 2, by forming the bearing housing with a thermal expansion material having a negative coefficient of thermal expansion from the low temperature range to the medium temperature range and having a positive coefficient of thermal expansion from the medium temperature range to the high temperature range, The gap between the bearing housing and the rotating shaft to which the lubricating oil is supplied is increased in the low temperature range, decreased in the intermediate temperature range, and increased again in the high temperature range. Thereby, suppression of friction in a low temperature region, suppression of deterioration of fuel consumption in a middle temperature region, and suppression of oil film breakage in a high temperature region are achieved.

JP-A-5-256320 JP 2008-309199 A JP 2005-264179 A JP 2006-283905 A

  When the rotating shaft is supported by a radial slide bearing through the lubricating oil, the viscosity of the lubricating oil is high at a low temperature, so that the viscous friction loss when the rotating shaft rotates increases. In order to reduce the viscous friction loss, it is necessary to quickly raise the temperature of the lubricating oil to quickly lower the viscosity of the lubricating oil, and for that purpose, it was supplied to the gap between the bearing and the rotating shaft. It is desirable to retain the lubricating oil and promote the temperature rise of the lubricating oil by stirring heat generation of the retained lubricating oil itself. On the other hand, in order to improve the lubrication performance and cooling performance by the lubricating oil at high temperatures when the viscosity of the lubricating oil is low and the viscous friction loss is small, the lubricating oil supplied to the gap between the bearing and the rotating shaft is discharged. It is desirable to promote lubricating oil circulation.

  In Patent Document 1, the gap between the bearing metal and the rotating shaft is smaller at both ends in the axial direction than at the center regardless of whether the temperature is low or high. Therefore, at low temperatures, it is possible to raise the temperature of the lubricating oil by stirring heat generation of the lubricating oil staying in the gap between the bearing metal and the rotating shaft, but even at high temperatures, the bearing metal and the rotating shaft The lubricating oil stays in the gap between the two and the circulation of the lubricating oil is not promoted. Further, at high temperatures, both ends of the bearing metal in the axial direction and the rotating shaft may come into contact with each other and wear and seizure may occur.

  Further, in Patent Document 2, since the gap between the bearing housing and the rotating shaft becomes large and the lubricating oil does not stay at low temperatures, the temperature rise of the lubricating oil is promoted by stirring heat generation of the retained lubricating oil itself. Is difficult. Therefore, it is difficult to quickly reduce the viscosity of the lubricating oil by reducing the viscosity friction loss by increasing the temperature of the lubricating oil.

  An object of the present invention is to promote the temperature rise of a lubricating oil at a low temperature and promote the circulation of the lubricating oil at a high temperature when the rotary shaft is supported by a radial slide bearing via the lubricating oil.

  The radial slide bearing and the rotating shaft bearing structure according to the present invention employ the following means in order to achieve the above-described object.

  The radial plain bearing according to the present invention is a radial plain bearing having a half structure in which a lining layer is formed on the inner peripheral side of the back metal and the rotating shaft is supported by the lining layer via a lubricating oil. A first back metal layer thicker than the first layer, and a second back metal layer disposed between the first back metal layer and the lining layer, the thermal expansion coefficient of the second back metal layer being The gist is that it is higher than the thermal expansion coefficient of the 1 back metal layer.

  According to the above configuration, the lubricating oil supplied to the gap between the lining layer and the rotary shaft is reduced at a low temperature by narrowing the gap (oil relief) with respect to the rotary shaft in the vicinity of the split surface of the radial slide bearing. And the temperature rise of the lubricating oil can be promoted by the heat generated by stirring the lubricating oil. On the other hand, at a high temperature, the thermal expansion amount of the second back metal layer on the inner peripheral side is larger than the thermal expansion amount of the first back metal layer on the outer peripheral side, so that in the vicinity of the split surface of the radial plain bearing. Since the clearance (oil relief) with respect to the rotating shaft of the shaft becomes wider, the discharge of the lubricating oil supplied to the clearance between the lining layer and the rotating shaft can be promoted, and the circulation of the lubricating oil can be promoted. .

Furthermore, in this onset bright, back metal, the central portion from both end portions of the rotation axis direction that is recessed toward the outer periphery.

  According to the above configuration, when the temperature is low, the clearance (side clearance) with respect to the rotating shaft at both ends in the rotating shaft direction of the radial slide bearing is narrowed so that the gap is supplied to the clearance between the lining layer and the rotating shaft. Lubricating oil is retained, and the temperature rise of the lubricating oil can be promoted by the heat generated by stirring the lubricating oil. On the other hand, at the time of high temperature, both ends of the radial slide bearing in the rotational axis direction are caused by the thermal expansion of the back metal in which the thermal expansion amount of the second back metal layer on the inner peripheral side is larger than the thermal expansion amount of the first back metal layer on the outer peripheral side. The clearance (side clearance) with respect to the rotating shaft at the part becomes wider, so that the discharge of the lubricating oil supplied to the clearance between the lining layer and the rotating shaft can be promoted, and the circulation of the lubricating oil can be promoted Can do.

  In one aspect of the present invention, it is preferable that the radial plain bearing is mounted on a large end portion of a connecting rod of an internal combustion engine, and the crankshaft of the crankshaft is supported by a lining layer via lubricating oil as the rotating shaft. .

  The bearing structure of the rotating shaft according to the present invention is a rotating shaft bearing structure in which the rotating shaft is supported by a radial slide bearing through lubricating oil, and the radial slide bearing is a radial slide bearing according to the present invention. It is a summary.

  As described above, according to the present invention, when the rotary shaft is supported by the radial slide bearing via the lubricating oil, the temperature rise of the lubricating oil can be promoted at a low temperature, and the lubricating oil is circulated at a high temperature. Can be promoted.

It is a figure showing a schematic structure of a connecting rod of an internal-combustion engine in which a radial slide bearing concerning an embodiment of the present invention is used. It is a figure which shows the outline of the bearing structure of the rotating shaft using the radial slide bearing which concerns on embodiment of this invention. It is a figure which shows the outline of the bearing structure of the rotating shaft using the radial slide bearing which concerns on embodiment of this invention. It is a figure explaining the effect | action of the radial slide bearing which concerns on embodiment of this invention. It is a figure explaining the effect | action of the radial slide bearing which concerns on embodiment of this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as embodiments) will be described with reference to the drawings.

  FIG. 1 is a view showing a schematic configuration of a connecting rod of an internal combustion engine in which a radial slide bearing according to an embodiment of the present invention is used, and FIGS. 2 and 3 use the radial slide bearing according to the embodiment of the present invention. It is a figure which shows the outline of the bearing structure of a rotating shaft. 1 and 2 show views seen from the direction of the rotation axis, and FIG. 3 shows a view seen from the direction perpendicular to the direction of the rotation axis. However, in each figure including FIGS. 1 to 3, the thickness of the radial slide bearing (large end bearing) and the size of the clearance between the rotary shaft (crank pin) and the radial slide bearing (large end bearing), etc. These are shown larger than the actual size for convenience of explanation.

  The connecting rod 10 of the internal combustion engine is a component that converts the reciprocating linear motion of the piston 11 to a crankshaft (not shown) and converts it into a rotational motion. As shown in FIG. 1, the connecting rod 10 includes a small end portion 12 on the piston 11 side, a large end portion 13 on the crankshaft side, and a column portion 14 that connects between the small end portion 12 and the large end portion 13. It is composed of The connecting rod 10 is made of a material such as nickel / chromium steel, chromium / molybdenum steel, or titanium alloy, and is a member that requires high mechanical strength.

  The small end portion 12 is a connection portion with the piston 11, and a small end portion through-hole 16 through which the piston pin 15 coupled to the piston 11 is inserted is formed. The small end through hole 16 is provided with a small end bearing 17 for supporting the piston pin 15. Since the small end bearing 17 receives, for example, a high load in the explosion stroke via the piston 11, a high load capacity is required. The movement form of the small end 12 is a swinging movement from the combination of the reciprocating movement of the entire connecting rod 10 and the rotational movement of the large end 13, so that the small end bearing 17 has a wide range of bearing inner peripheral surfaces. A high load acts over the range. Therefore, for example, lubricating oil is supplied to the inner peripheral surface of the bearing from a jet hole or a communication hole (not shown) formed in the large end portion 13 to support the axial load via the lubricating oil.

  The large end portion 13 is a connecting portion with the crankshaft, and a large end through hole 19 into which the crankpin 18 of the crankshaft is inserted is formed. The large end through hole 19 is provided with a large end bearing 30 for supporting the crank pin 18. The large end portion 13 includes a large end body 20 integrally formed with the column portion 14 and a cap 21 fastened to the large end portion body 20. The large end portion main body 20 is fastened with the cap 21. A large end bearing 30 having a half structure is attached to the large end through-hole 19 to be formed.

  As described above, the column portion 14 is a portion that connects between the small end portion 12 and the large end portion 13. Generally, the column portion 14, the small end portion 12, and the large end portion main body 20 are integrated. Molded. For example, a communication hole (not shown) is formed in the column portion 14 in order to supply the lubricating oil from the large end portion 13 to the small end portion 12. Further, as described above, the crankpin 18 is a shaft that connects the crankshaft and the large end portion 13 and is rotated by receiving the force due to the reciprocating motion of the piston 11 and transmits the force to the crankshaft. It is a member for.

  As described above, when the connecting rod 10 connects the piston 11 and the crank pin 18 of the crankshaft, when the piston 11 reciprocates in a cylinder (not shown) during operation of the engine, the reciprocating motion is transmitted through the connecting rod 10. It is converted into the rotational motion of the crankshaft, and the rotational power of the crankshaft is obtained as engine output.

  The large end bearing 30 is a radial slide bearing (also referred to as a journal slide bearing) that supports the crank pin 18 that is a rotating shaft through lubricating oil. As shown in FIG. It is constituted by a half bearing 31 having a substantially half cylindrical shape divided into two. One half bearing 31 is attached to the large end body 20 as a bearing support member, and the other half bearing 31 is attached to a cap 21 as a bearing support member, and both ends of the two half bearings 31 in the circumferential direction. By combining the parts, a substantially cylindrical large end bearing 30 is formed. The half bearing 31 includes a backing metal 32 and a bearing alloy layer 33 as a lining layer formed on the inner peripheral side of the backing metal 32. An oil supply passage is formed in the crankshaft, and lubricating oil is supplied to a gap between the outer peripheral surface of the crankpin 18 and the bearing alloy layer 33 through the oil supply passage. The large-end bearing 30 having a half structure supports the crank pin 18 with a lining layer (bearing alloy layer 33) through lubricating oil. The main role of the lubricating oil here is to reduce the friction loss and wear between the shaft and the inner circumferential surface of the bearing by operating the engine without forming the oil film by forming an oil film. Also plays a role of cooling, cleaning, rust prevention and so on.

  In the present embodiment, the backing metal 32 is a low thermal expansion coefficient backing metal layer 34 and a high thermal expansion coefficient disposed between the low thermal expansion coefficient backing metal layer 34 and the bearing alloy layer 33 (the inner peripheral side of the low thermal expansion coefficient backing metal layer 34). The back metal layer 35 includes a back metal layer 35. The low thermal expansion coefficient back metal layer 34 and the high thermal expansion coefficient back metal layer 35 both have a positive thermal expansion coefficient. Further, the inner peripheral side high thermal expansion coefficient back metal The thermal expansion coefficient of the layer 35 is higher than the thermal expansion coefficient of the low thermal expansion coefficient backing metal layer 34 on the outer peripheral side. The thickness of the high thermal expansion coefficient backing metal layer 35 is equal to (or substantially equal to) the thickness of the low thermal expansion coefficient backing metal layer 34, and the thickness of the low thermal expansion coefficient backing metal layer 34 and the thickness of the high thermal expansion coefficient backing metal layer 35 are both. It is thicker than the thickness of the bearing alloy layer 33. Examples of the type of the low thermal expansion coefficient backing metal layer 34 include steel, and examples of the type of the high thermal expansion coefficient backing metal layer 35 include an aluminum alloy and a copper alloy. Moreover, as a kind of the bearing alloy layer 33, a copper-lead alloy, an aluminum alloy, etc. are mentioned, for example. It is also possible to form an overlay on the inner peripheral side of the bearing alloy layer 33.

  Further, in the present embodiment, the half bearing 31 (back metal 32 and bearing alloy layer 33) is curved with respect to the direction of the rotation axis so that the center part is recessed toward the outer peripheral side from both ends in the direction of the rotation axis, as shown in FIG. ing. As a result, the clearance of the half bearing 31 (bearing alloy layer 33) with respect to the crankpin 18 is narrower at both ends in the direction of the rotation axis than at the center. In this state, the half bearing 31 (back metal 32) contacts the large end portion 13 (the large end main body 20 or the cap 21) as a bearing support member at the center with respect to the rotation axis direction, and the rotation shaft direction. At both ends, a minute clearance is formed between the large end 13 (the large end main body 20 or the cap 21). Further, in the circumferential direction, a minute clearance is formed between the half bearing 31 (back metal 32) and the large end portion 13 (the large end main body 20 or the cap 21) in the vicinity of the mating surfaces (both end portions).

  When the temperature of the half bearing 31 is low, such as immediately after a cold start of the internal combustion engine, the clearance (oil relief) 36 with respect to the crankpin 18 near the mating surface of the half bearing 31 becomes narrow as shown in FIG. Accordingly, the discharge of the lubricating oil filled in the gap between the crankpin 18 and the bearing alloy layer 33 is suppressed. Further, when the temperature of the half bearing 31 is low, as shown in FIG. 3, both end portions in the rotation axis direction of the half bearing 31 (back metal 32) protrude from the center to the inner peripheral side (crank pin 18 side). In addition, the clearance (side clearance) 37 with respect to the crankpin 18 at both ends in the rotation axis direction of the half bearing 31 is narrowed, and the lubrication filled in the gap between the crankpin 18 and the bearing alloy layer 33 is also achieved. Oil discharge is suppressed.

  At low temperatures, the viscosity of the lubricating oil is high, and viscous friction loss tends to increase when the crankpin 18 rotates with respect to the large end portion 13. In this embodiment, the oil relief 36 and the side are at low temperatures. The clearance 37 is narrowed. Therefore, at a low temperature, the lubricating oil filled in the gap between the crankpin 18 and the bearing alloy layer 33 stays, and the temperature rise of the lubricating oil is promoted by the stirring heat generation of the retained lubricating oil itself. Accordingly, the viscosity of the lubricating oil can be quickly lowered, and the viscous friction loss when the crankpin 18 rotates with respect to the large end portion 13 can be reduced.

  When the temperature of the half bearing 31 increases with the operation of the internal combustion engine, the back metal 32 is thermally expanded. During the thermal expansion of the back metal 32, the thermal expansion coefficient of the high thermal expansion coefficient back metal layer 35 is higher than the thermal expansion coefficient of the low thermal expansion coefficient back metal layer 34. It becomes larger than the thermal expansion amount of the low thermal expansion coefficient backing metal layer 34 on the outer peripheral side. Therefore, when the temperature of the half bearing 31 is high, such as during steady operation of the internal combustion engine, the curvature in the circumferential direction of the back metal 32 is smaller than when the temperature of the half bearing 31 is low, as shown in FIG. As described above, the clearance (oil relief) 36 with respect to the crankpin 18 in the vicinity of the mating surface of the half bearing 31 is widened. As a result, the discharge of the lubricating oil filled in the gap between the crankpin 18 and the bearing alloy layer 33 is promoted. In this state, the half bearing 31 (back metal 32) is in contact with the large end 13 (the large end body 20 or the cap 21) even in the vicinity of the mating surfaces (both ends) in the circumferential direction.

  Further, when the temperature of the half bearing 31 is high, the curvature of the backing metal 32 in the direction of the rotation axis is smaller than when the temperature of the half bearing 31 is low, and as shown in FIG. The clearances (side clearances) 37 with respect to the crankpin 18 at both ends in the rotation axis direction become wider. This also facilitates the discharge of the lubricating oil filled in the gap between the crankpin 18 and the bearing alloy layer 33. In this state, the half bearing 31 (back metal 32) is in contact with the large end 13 (the large end main body 20 or the cap 21) at both ends in the rotation axis direction. In that case, the clearance with respect to the crankpin 18 of the half bearing 31 is uniform in the rotation axis direction at a temperature corresponding to the steady operation of the internal combustion engine (equal to both ends and the center portion in the rotation axis direction). Furthermore, it is preferable to design the curvature with respect to the rotation axis direction of the back metal 32 at a low temperature.

  Thus, in the present embodiment, the oil relief 36 and the side clearance 37 are widened by the thermal expansion of the back metal 32 at a high temperature when the viscosity of the lubricating oil is low and the viscous friction loss is small. Accordingly, the circulation of the lubricating oil can be promoted at a high temperature, and the lubricating performance and cooling performance by the lubricating oil can be improved.

  In the present embodiment described above, the back metal 32 can be made to have a bimetal structure with the low thermal expansion coefficient back metal layer 34 and the high thermal expansion coefficient back metal layer 35 for both of the half bearings 31 divided into two. However, in the present embodiment, the back metal 32 may have a bimetallic structure including a low thermal expansion coefficient back metal layer 34 and a high thermal expansion coefficient back metal layer 35 for either one of the half bearings 31 divided into two. Note that, as in Patent Documents 3 and 4, in a structure in which a bearing alloy layer is formed on a single-layer (non-bimetallic structure) back metal, the thickness of the bearing alloy layer is smaller than that of the back metal, and oil relief or side at low temperatures It is difficult to obtain a sufficient effect of narrowing the clearance and widening the oil relief and side clearance by thermal expansion at high temperatures.

  In general, in a bimetallic structure having a length l made of a material 1 having a thickness h1, an elastic constant E1, and a linear expansion coefficient α1, and a material 2 having a thickness h2, an elastic constant E2, and a linear expansion coefficient α2, the temperature is increased by ΔT. The displacement δ generated at the end portion is expressed by the following equation (1) (refer to Metal Manual 6.6, p942).

δ = 6 × ΔT × (α1-α2) × l ² × m × n
/ [(H1 + h2) × (m + 1) × (n + 1) × (m × n + 1)] (1)
However, m = E2 / E1, n = h2 / h1

In this embodiment, the low thermal expansion coefficient back metal layer 34 (material 1) is steel (E1 = 2.1 × 10 ¹¹ Pa, α1 = 1.1 × 10 ⁻⁵ ) having a thickness h1 = 1.25 mm, and high thermal expansion. When the rate back metal layer 35 (material 2) is an aluminum alloy having a thickness h2 = 1.25 mm (E2 = 7.0 × 10 ¹⁰ Pa, α2 = 2.2 × 10 ⁻⁵ ), ΔT = 50 ° C. (for example, 20 When the temperature rises (° C. → 70 ° C.), the clearance change at the bearing oil relief position with a diameter of 40 mm is about 0.11 mm from the equation (1), and the bearing end and center portion with a width of 15 mm in the rotation axis direction The clearance change is about 7 μm. On the other hand, in a structure in which a bearing alloy layer is formed on a single-layer (non-bimetallic structure) back metal, the back metal (material 1) is steel having a thickness h1 = 2.3 mm (E1 = 2.1 × 10 ¹¹ Pa, α1 = 1.1 × 10 ⁻⁵ ) and the bearing alloy layer (material 2) is an aluminum alloy (E2 = 7.0 × 10 ¹⁰ Pa, α2 = 2.2 × 10 ⁻⁵ ) having a thickness h2 = 0.2 mm. Then, when a temperature increase of ΔT = 50 ° C. occurs, the change in the clearance at the bearing oil relief position with a diameter of 40 mm is about 0.02 mm from the equation (1), and the bearing end and center of the width 15 mm in the rotation axis direction are The clearance change of the part is about 1.4 μm. Therefore, as in Patent Documents 3 and 4, in the structure in which the bearing alloy layer is formed on the back metal (not bimetal structure), the clearance change due to thermal expansion is small, and the oil relief and side clearance are narrowed at low temperatures. It becomes difficult to obtain a sufficient effect of widening oil relief and side clearance due to thermal expansion at high temperatures.

  In the above description, the large-end bearing 30 of the connecting rod 10 has been described as an example of the rotating shaft bearing structure using the radial slide bearing according to the embodiment of the present invention. However, the bearing structure of the rotating shaft using the radial slide bearing according to the present invention can be applied to other engine member bearings such as a camshaft bearing in addition to the large end bearing 30 of the connecting rod 10. It is also possible to apply to applications other than bearings for engine members. As described above, the rotary shaft bearing structure using the radial slide bearing according to the present invention can be applied to various bearings as long as the rotary shaft is supported by the radial slide bearing through the lubricating oil. is there.

  As mentioned above, although the form for implementing this invention was demonstrated, this invention is not limited to such embodiment at all, and it can implement with a various form in the range which does not deviate from the summary of this invention. Of course.

  10 connecting rod, 11 piston, 12 small end, 13 large end, 14 column, 15 piston pin, 16 small end through hole, 17 small end bearing, 18 crank pin, 19 large end through hole, 20 Large end body, 21 cap, 30 Large end bearing, 31 Half bearing, 32 Back metal, 33 Bearing alloy layer, 34 Low thermal expansion back metal layer, 35 High thermal expansion back metal layer, 36 Oil relief, 37 Side clearance.

Claims (3)

A radial sliding bearing with a halved structure in which a lining layer is formed on the inner peripheral side of the back metal and the rotating shaft is supported by the lining layer via lubricating oil,
The back metal includes a first back metal layer thicker than the lining layer; and a second back metal layer disposed between the first back metal layer and the lining layer and thicker than the lining layer;
Thermal expansion coefficient of the second backing layer is rather high than the thermal expansion coefficient of the first back metal layer,
The back metal is a radial plain bearing in which the central part is recessed from the both ends in the direction of the rotation axis toward the outer periphery . A radial plain bearing according to claim 1,
A radial slide bearing is a radial slide bearing that is attached to a large end portion of a connecting rod of an internal combustion engine and supports a crankpin of a crankshaft as a rotating shaft with a lining layer through lubricating oil . A rotating shaft bearing structure in which the rotating shaft is supported by a radial slide bearing through lubricating oil ,
The bearing structure of a rotating shaft, wherein the radial slide bearing is the radial slide bearing according to claim 1 or 2 .

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