JP2016090025A - Half-split bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a leakage oil amount compared to conventional ones.SOLUTION: When a shaft is rotated at 6600 rpm, by making a ratio of a depth t12 of a second groove 12 to a radius r into less than 1.54%, a leakage oil amount of a half-split bearing 1 is smaller than a leakage oil amount of a conventional half-split bearing 7. Also, by making a ratio of a width w12 of the second groove 12 to the whole width w of the half-split bearing 1 into less than 11%, the leakage oil amount of the half-split bearing 1 is smaller than the leakage amount of the conventional half-split bearing 7. Further, by making a ratio of a length L12 of the second groove 12 to the whole length L along the circumferential direction of the inner peripheral surface 13 of the half-split bearing 1 into 2.45% or more, the leakage oil amount of the half-split bearing 1 is smaller than the leakage oil amount of the conventional half-split bearing 7.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a technique for reducing the amount of lubricating oil leaking from a half bearing.

  A crankshaft (main shaft) of an internal combustion engine is supported by a main bearing comprising a pair of semi-cylindrical bearings (referred to as half bearings). In order to lubricate the main bearing, the lubricating oil discharged by the oil pump is supplied to an oil groove formed along the inner peripheral surface of the main bearing through a through hole formed in the wall of the main bearing. .

  In the prior art, the oil groove of the main bearing is formed on the inner peripheral surface of at least one of the pair of half bearings at the same depth over the entire length in the circumferential direction. In this case, the lubricating oil supplied to the oil groove flows to the circumferential end of the half bearing, and most of the lubricating oil is discharged outside the bearing through a groove formed in the axial direction at the joint of the half bearing. When the oil groove is formed at the same depth over the entire length in the circumferential direction as described above, lubricating oil corresponding to the volume of the formed oil groove is required, and the amount of lubricating oil leaked (hereinafter referred to as leakage oil amount) increases.

In order to reduce the amount of oil leaked from the oil groove provided in the bearing, various groove shapes have been studied.
Patent Document 1 describes an oil supply groove formed in a step shape so that the groove width is switched to the narrow groove width of the opening at the end (paragraph 84).
In Patent Document 2, an oil groove is formed in the circumferential direction from one lower end surface to the other lower end surface on the inner peripheral surface side, and the depth of the oil groove is eccentric with respect to the inner periphery, and the lower end surface Describes an "eccentric oil groove type" upper metal that is "0" (paragraph 26).

JP 2005-69248 A JP 2011-179366 A

  However, in the technique described in Patent Document 2, although the groove becomes shallower as it approaches the joint surface, the width of the groove is constant, so that a certain amount of oil leaks according to the width.

  In the technique described in Patent Document 1, since the groove has a “throttle portion” whose width becomes narrower discontinuously on the way to the joint surface where the half bearings are joined, there is an effect of reducing the amount of leaked oil. . However, no examination has been made as to how effectively the narrowed portion is effectively sized.

  One of the objects of the present invention is to suppress the amount of oil leakage as compared with the prior art.

  In order to solve the above-described problems, a half bearing according to the present invention is a half bearing that forms a cylindrical bearing that accommodates a shaft on the inner peripheral surface side as a whole by abutting with another pair of half bearings. The first and second joint surfaces are formed along the circumferential direction of the inner peripheral surface and do not reach any of the two joint surfaces. And a first groove having an opening extending from an end of the first groove in the circumferential direction to the joint surface closer to the end of the two joint surfaces. A second groove having a narrower second width, and the depth of the second groove from the inner peripheral surface is less than 1.54% with respect to the radius of the inner peripheral surface It is characterized by.

  In the above aspect, the second width is preferably less than 11% with respect to the entire width of the inner peripheral surface.

  In the above aspect, the length of the second groove on the inner peripheral surface along the circumferential direction is preferably 2.45% or more with respect to the total length of the inner peripheral surface in the circumferential direction. .

  According to the present invention, the amount of leaked oil can be suppressed as compared with the prior art.

The figure which shows the outline | summary of a half bearing. The figure for demonstrating the depth of the groove | channel in a half bearing. The figure which shows an example of the conventional half bearing. The figure for demonstrating the depth of the groove | channel in a half bearing. The perspective view which shows the dimension of the 2nd groove | channel of a half bearing. The graph which shows the numerical calculation result at the time of changing groove depth. The graph which shows the numerical calculation result at the time of changing groove width. The graph which shows the numerical calculation result at the time of changing groove length.

1. Embodiment Hereinafter, the structure of the half bearing 1 which concerns on one Embodiment of this invention is demonstrated. In the figure, a space in which each component of the half bearing 1 is arranged is represented as an xyz right-handed coordinate space. Among the coordinate symbols shown in the figure, a symbol in which two oblique lines intersecting each other in a white circle represent an arrow heading from the front side to the back side of the page. A direction along the x-axis in space is referred to as an x-axis direction. Of the x-axis directions, the direction in which the x component increases is referred to as + x direction, and the direction in which the x component decreases is referred to as -x direction. For the y and z components, the y-axis direction, + y direction, -y direction, z-axis direction, + z direction, and -z direction are defined according to the above definition.

  FIG. 1 is a diagram showing an outline of the half bearing 1. The half bearing 1 is an upper half bearing that forms a cylindrical slide bearing that accommodates a shaft on the inner peripheral surface 13 as a whole by abutting with a pair of lower half bearings (not shown). It is. The shaft accommodated on the inner peripheral surface 13 side by the half bearing 1 is a crank shaft (main shaft). In FIG. 1, the half bearing 1 is arranged so that the shaft accommodated on the inner peripheral surface 13 side is along the x-axis direction. In FIG. 1, the + z direction is upward and the −z direction is downward.

  FIG. 1A shows the shape of the half bearing 1 as viewed in the direction from the bottom to the top (+ z direction). As shown in FIG. 1A, the full width w of the half bearing 1 is the total length in the x-axis direction and is constant at any position.

  A first groove 11 having a width w11 is formed on the inner circumferential surface 13 of the half bearing 1 along the circumferential direction in the center in the width direction (x-axis direction). Oil holes H11 and H12 penetrating toward the outer peripheral surface 19 are provided at predetermined positions in the first groove 11. A casing (not shown) that supports the half bearing 1 from the outer peripheral surface 19 side is provided with a lubricating oil supply port, and the lubricating oil is supplied from the oil supply port to the oil holes H11 and H12. The number of oil holes is not limited to 2 and may be 1 or 3 or more.

FIG. 1B shows a cross-sectional view of the half bearing 1 cut along the center in the width direction (x-axis direction) (arrow Ib-Ib in FIG. 1A). The shaft accommodated in the inner peripheral surface 13 rotates along the arrow D. The upstream side and the downstream side are defined by the rotation direction indicated by the arrow D.
The center O of the shaft accommodated on the inner peripheral surface 13 side of the half bearing 1 coincides with the center of the inner peripheral surface 13. The inner peripheral surface 13 is a semi-cylindrical curved surface having a radius r from the center O.

  The joining surface 14 is an upstream joining surface, and the joining surface 15 is a downstream joining surface. The joint surfaces 14 and 15 are joint surfaces that abut against the joint surface of the halved bearing on the lower side (−z direction). The oil hole H11 is located upstream of the oil hole H12.

  In the first groove 11 formed on the inner peripheral surface 13, both ends in the circumferential direction do not reach either the bonding surface 14 or the bonding surface 15 as shown in FIG. The area | region in which the 1st groove | channel 11 was formed among the internal peripheral surfaces 13 is called 1st area | region A1. Of the inner peripheral surface 13, a region downstream of the first region A1 is defined as a second region A2, and a region upstream of the first region A1 is defined as a third region A3. The upstream end of the first region A1 is located closer to the joining surface 14 than the joining surface 15, and the downstream end of the first region A1 is located closer to the joining surface 15 than the joining surface 14. is there.

  If the intermediate point C shown in FIG. 1 (b) is an intermediate position between the joint surfaces 14 and 15 in the circumferential direction of the inner peripheral surface 13, the upstream end of the first region A1 is It can be said that the downstream end of the first region A1 is downstream of the intermediate point C in the circumferential direction of the inner peripheral surface 13 and is located upstream of the intermediate point C in the circumferential direction of the peripheral surface 13.

  The 1st groove | channel 11 becomes shallow, so that it approaches both ends from the intermediate point C of 1st area | region A1. That is, the 1st groove | channel 11 is formed so that it may become shallow, so that the nearer one of the joint surfaces 14 and 15 is approached.

  The second groove 12 is formed so as to open from the end of the first groove 11 in the circumferential direction of the inner peripheral surface 13 to the joint surface closer to the end of the two joint surfaces 14 and 15. Has been. In the example shown in FIG. 1, there are two second grooves 12, and each extends from both ends of the first groove 11 to the joining surfaces 14 and 15 along the circumferential direction. That is, in this example, the second groove 12 is provided in each of the second region A2 on the downstream side of the first region A1 and the third region A3 on the upstream side of the first region A1.

The length of the groove is determined by the length along the circumferential direction of the inner peripheral surface 13. In the half bearing 1 shown in FIG. 1, the length of the second groove 12 provided in the second region A2 is the same as the length of the second groove 12 provided in the third region A3. The length of the second groove 12 provided in the second region A2 is a length L12 shown in FIG. The second area A2 is an arc-shaped area at the center O, and when the angle is θ (rad: radians angle), the length L12 is calculated according to the following equation (1).
L12 = r × θ (1)
On the other hand, the total length L in the circumferential direction of the inner peripheral surface 13 of the half bearing 1 is calculated according to the following equation (2).
L = r × π (2)
This is because the half bearing 1 has a semi-cylindrical shape in which the cylinder is divided by a plane passing through the center O. Therefore, the angle corresponding to the entire area of the inner peripheral surface 13 is equivalent to two right angles, that is, π (rad). Because it becomes.

  The second groove 12 is a narrower groove than the first groove 11. That is, the width w12 of the second groove 12 has a relationship of w12 <w11 with the width w11 of the first groove 11.

  The second groove 12 is formed at a certain depth from the end of the first groove 11 to the closer one of the joint surfaces 14 and 15.

  FIG. 2 is a view for explaining the depth of the groove in the half bearing 1. A sectional view of the half bearing 1 taken along the arrow IIa-IIa in FIG. 1B is shown in FIG. 2A, and a sectional view taken along the arrow IIb-IIb is shown in FIG. 2B. The cross section cut along the arrow IIa-IIa is a cross section including the center O and the intermediate point C, and the cross section cut along the arrow IIb-IIb is the boundary between the center O and the first region A1 and the second region A2. It is a cross section containing.

  As shown in FIG. 2A, in the cross section including the intermediate point C, the shape of the first groove 11 appears. The cross section at the midpoint C of the first groove 11 is a rectangle having a width w11 and a depth t11. The depth t11 of the first groove 11 is deepest in the cross section including the intermediate point C.

  As shown in FIG. 2B, the first groove 11 and the second groove 12 are switched at the boundary between the first region A1 and the second region A2, so that the end portion of the first groove 11 is shown in the cross section. The surface and the shape of the second groove 12 appear. The depth t12 of the second groove 12 is a depth with reference to the inner peripheral surface 13, and is a distance from the inner peripheral surface 13 measured along a line extending radially from the center O on the yz plane.

  In the cross section at the boundary between the first region A1 and the second region A2 shown in FIG. 2B, the depth t12 of the second groove 12 is shallower than the depth t11 of the first groove 11, and Since the width w12 of the second groove 12 is narrower than the width w11 of the first groove 11, the oil channel held in the first groove 11 is a second groove having a small cross-sectional area in the second region A2 on the downstream side. Switch to 12. That is, the second groove 12 functions as a “squeezing part” that squeezes the flow of the first groove 11 at the end part.

2. Comparison with Prior Art FIG. 3 is a diagram showing an example of a conventional half bearing. The half bearing 7 is an example of a conventional half bearing, and is, for example, an eccentric oil groove type upper metal described in Patent Document 2.

  The half bearing 7 is an upper half bearing that forms a cylindrical slide bearing that accommodates a shaft on the inner peripheral surface 73 as a whole by abutting with a pair of lower half bearings (not shown). It is. The shaft accommodated on the inner peripheral surface 73 side by the half bearing 7 is a crank shaft (main shaft). In FIG. 3, the half bearing 7 is arranged so that the shaft accommodated on the inner peripheral surface 73 side is along the x-axis direction. In FIG. 3, the + z direction is upward and the −z direction is downward.

  FIG. 3A shows the shape of the half bearing 7 as viewed in the direction from the bottom to the top (+ z direction). FIG. 3B shows a cross-sectional view of the half bearing 7 cut at the center in the width direction (x-axis direction) (arrow IIIb-IIIb in FIG. 3A).

  In the half bearing 7, a groove 71 having a constant width w71 is formed from the upstream joint surface 74 to the downstream joint surface 75 in the rotation direction of the shaft. Oil holes H71 and H72 penetrating toward the outer peripheral surface 79 are provided at predetermined positions in the groove 71. The depth of the groove 71 is deepest at the intermediate point C and becomes shallower as it approaches both ends. That is, the groove 71 is formed so as to become shallower as it approaches the closer one of the joint surfaces 74 and 75.

  FIG. 4 is a view for explaining the depth of the groove in the half bearing 7. FIG. 4 shows a cross-sectional view of the half bearing 7 taken along the line IV-IV in FIG. The cross section cut along the arrow IV-IV is a cross section including an intermediate point C that is an intermediate position between the joint surfaces 74 and 75 in the circumferential direction of the inner peripheral surface 73. In this case, the cross section at the midpoint C of the groove 71 is a rectangle having a width w71 and a depth t71.

  Here, when the width w71 is equal to the width w11 and the depth t71 is equal to the depth t11, there is no difference in the cross section of the groove including the center O and the intermediate point C between the half bearing 1 and the half bearing 7.

  On the other hand, the groove 71 is formed so as to become shallower as it approaches the closer one of the joint surfaces 74 and 75 as described above, and thus retains oil as it approaches the joint surface 74 or the joint surface 75 from the intermediate point C. Although the cross-sectional area of the groove 71 is small, the cross-sectional area of the second groove 12 serving as a constricted portion is smaller than that of the groove 71 at the boundary between the first region A1 and the second region A2. Therefore, the amount of oil leaked in the half bearing 1 is less than that in the half bearing 7.

3. Calculation Example FIG. 5 is a perspective view showing dimensions of the second groove 12 of the half bearing 1. As shown in FIG. 5, the second groove 12 is a groove having a depth t12, a width w12, and a length L12.
Here, as a result of numerical calculation, it has been clarified that these dimensions of the second groove 12 are limited to a certain range for each of them, so that the amount of oil leakage is suppressed more than before. Hereinafter, these ranges will be described based on the numerical calculation results.

  The inventors of the present invention calculate the amount of leaked oil by numerical calculation when each of (1) groove depth, (2) groove width, and (3) groove length of the second groove 12 is changed. Then, the amount of leaked oil was compared with the amount of leaked oil when the half bearing 7 which is the prior art was used. For this numerical calculation, oil film analysis by Reynolds equation considering mass conservation was used. Further, in this numerical calculation, the shafts accommodated on the respective inner peripheral surfaces of the sliding bearing including the half bearing 1 or the half bearing 7 are rotated at 6600 rpm which is high speed rotation and 2000 rpm which is low speed rotation, respectively. The case where it was made to go.

(1) Groove depth FIG. 6 is a graph showing numerical calculation results when the groove depth is changed. The horizontal axis in FIG. 6 is a percentage indicating the ratio of the depth t12 of the second groove 12 to the radius r. The vertical axis in FIG. 6A indicates the amount of leaked oil per unit time when the shaft is rotated at 6600 rpm. The comparative example shown in FIG. 6A shows the amount of leaked oil when the shaft is rotated at 6600 rpm using the conventional half bearing 7 with a line indicating only the value of the vertical axis.

  As a result of this numerical calculation, when the shaft is rotated at 6600 rpm, the ratio of the depth t12 of the second groove 12 to the radius r is set to less than 1.54%, whereby the amount of leakage oil of the half bearing 1 is It has been found that the amount of oil leaked from the conventional half bearing 7 is suppressed.

  The vertical axis in FIG. 6B indicates the amount of oil leaked per unit time when the shaft is rotated at 2000 rpm, and the comparative example shown in FIG. 6B uses a conventional half bearing 7. The amount of leaked oil when the shaft is rotated at 2000 rpm is shown. As a result of this numerical calculation, when the shaft is rotated at 2000 rpm, the leakage oil amount of the half bearing 1 is suppressed more than the leakage oil amount of the conventional half bearing 7 regardless of the depth of the second groove 12. I found out that

(2) Groove Width FIG. 7 is a graph showing numerical calculation results when the groove width is changed. The horizontal axis of FIG. 7 is a percentage indicating the ratio of the width w12 of the second groove 12 to the full width w of the half bearing 1. The vertical axis in FIG. 7A indicates the amount of leaked oil per unit time when the shaft is rotated at 6600 rpm. The comparative example shown in FIG. 7A shows the amount of oil leaked when the conventional half bearing 7 is used, as in FIG.

  As a result of this numerical calculation, when the shaft is rotated at 6600 rpm, the ratio of the width w12 of the second groove 12 to the total width w of the half bearing 1 is less than 11%. It was found that the amount was suppressed more than the amount of oil leaked from the conventional half bearing 7.

  The vertical axis in FIG. 7B shows the amount of oil leaked per unit time when the shaft is rotated at 2000 rpm, and the comparative example shown in FIG. 7B uses a conventional half bearing 7. The amount of leaked oil when the shaft is rotated at 2000 rpm is shown. As a result of this numerical calculation, when the shaft is rotated at 2000 rpm, the leakage oil amount of the half bearing 1 is suppressed more than the leakage oil amount of the conventional half bearing 7 regardless of the width of the second groove 12. I found out.

(3) Groove Length FIG. 8 is a graph showing numerical calculation results when the groove length is changed. The horizontal axis of FIG. 8 is a percentage indicating the ratio of the length L12 of the second groove 12 to the total length L along the circumferential direction of the inner peripheral surface 13 of the half bearing 1. The vertical axis in FIG. 8A indicates the amount of leaked oil per unit time when the shaft is rotated at 6600 rpm. The comparative example shown to Fig.8 (a) shows the amount of leaked oil at the time of using the conventional half bearing 7 similarly to FIG.

  As a result of this numerical calculation, when the shaft is rotated at 6600 rpm, the ratio of the length L12 of the second groove 12 to the total length L of the inner peripheral surface 13 of the half bearing 1 is set to 2.45% or more. It was found that the amount of oil leaked from the half bearing 1 was suppressed more than the amount of oil leaked from the conventional half bearing 7.

  In addition, the vertical axis | shaft of FIG.8 (b) shows the amount of oil leaks per unit time when an axis | shaft is rotated at 2000 rpm, and the comparative example shown in FIG.8 (b) uses the conventional half bearing 7. FIG. The amount of leaked oil when the shaft is rotated at 2000 rpm is shown. As a result of this numerical calculation, when the shaft is rotated at 2000 rpm, the leakage oil amount of the half bearing 1 is suppressed more than the leakage oil amount of the conventional half bearing 7 regardless of the length of the second groove 12. I found out that

4). Modification The above is the description of the embodiment, but the contents of this embodiment can be modified as follows. Further, the following modifications may be combined.

4-1. Item of dimension In the above-described embodiment, the second groove 12 is formed so that the groove depth, the groove width, and the groove length are all within the ranges shown, but at least one of these is provided. May be formed to fall within the above range. For example, the second groove 12 only needs to have a ratio of the depth t12 to the radius r of less than 1.54%.

4-2. Positional Relationship with Crash Relief The joint surfaces 14 and 15 may be provided with a crush relief along the inner peripheral surface 13 respectively. In this case, the first groove 11 may be formed so as not to reach any of the crush reliefs of the two joint surfaces 14 and 15. Since the crush relief is formed by excavating the inner peripheral surface 13, for example, it is deeper than the position where the inner peripheral surface 13 was originally located. When the crush relief and the first groove 11 overlap, the oil retained in the first groove 11 leaks from the joint surfaces 14 and 15 not through the second groove 12 but through the crush relief, and thus the amount of leaked oil may increase. is there. Therefore, the amount of leaked oil is suppressed by forming the first groove 11 so as not to reach the crush relief.

4-3. In the embodiment described above, the second groove 12 includes the second region A2 that is downstream of the first region A1 and the third region A3 that is upstream of the first region A1. However, it may be provided only in the second region A2.

  When the supplied oil contains foreign matter, the foreign matter is often discharged along the oil flow. That is, the foreign matter is rarely discharged from the upstream side of the first groove 11 and is highly likely to be discharged from the downstream side. Therefore, even if the second groove 12 is not provided in the third region A3 on the upstream side of the first groove 11, it is possible to discharge the foreign matter if it is provided in the second region A2 on the downstream side. . Further, the oil supply amount is reduced by not forming the second groove 12 upstream of the first groove 11.

4-4. Coating Of the inner peripheral surface 13, a coating (referred to as a coating layer) may be applied to a portion where the first groove 11 and the second groove 12 are not formed. This coating layer may be, for example, resin, plating, hard film, solid lubricant, soft metal, or the like. Further, it may be obtained by modifying the surface of the inner peripheral surface 13 by chemical treatment or heat treatment. Thereby, the friction between the shaft and the inner peripheral surface 13 is reduced.

4-5. In the embodiment described above, the shape of the groove is an arc shape centered on the axis, but is not limited thereto. For example, the first groove 11 and the second groove 12 may be formed to be elliptical when viewed from the axial direction, or may be formed to draw a parabola when viewed from the axial direction.

DESCRIPTION OF SYMBOLS 1 ... Half bearing, 11 ... 1st groove, 12 ... 2nd groove, 13 ... Inner peripheral surface, 14 ... Joining surface, 15 ... Joining surface, 19 ... Outer peripheral surface, 7 ... Half bearing, 71 ... Groove, 73 ... inner peripheral surface, 74 ... bonding surface, 75 ... bonding surface, 79 ... outer peripheral surface, A1 ... first region, A2 ... second region, A3 ... third region, C ... middle point, D ... arrow, H11, H12 , H71, H72 ... oil holes, L ... full length, O ... center, w ... full width, w11 ... width, w12 ... width, w71 ... width.

Claims (3)

A half bearing that forms a cylindrical bearing that accommodates a shaft on the inner peripheral surface side as a whole by abutting with another pair of half bearings,
Two joint surfaces that abut the joint surfaces of the other half bearings;
A first groove having a first width formed along a circumferential direction of the inner peripheral surface and not reaching any of the two joint surfaces;
A second width narrower than the first width opens from the end of the first groove in the circumferential direction to the joint surface closer to the end of the two joint surfaces. A second groove,
The half bearing, wherein the depth of the second groove from the inner peripheral surface is less than 1.54% with respect to the radius of the inner peripheral surface. The half bearing according to claim 1, wherein the second width is less than 11% with respect to the entire width of the inner peripheral surface. The length along the circumferential direction of the second groove on the inner circumferential surface is 2.45% or more with respect to the total length of the inner circumferential surface in the circumferential direction. The half bearing described in 1.

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