JP2008082482A - Oil hole structure of connecting rod bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oil hole structure of a connecting rod bearing capable of preventing the occurrence of inconvenience such as seizure of the bearing caused by separation, by preventing the separation of a lining layer, by forming a cutting part and an exposure part in advance in a microscopic crack easily causing part. <P>SOLUTION: This half-split-shaped connecting rod bearing 4 is formed by laminating the lining layer 42 on a back plate 41, by being interposed between a crankshaft and a connecting rod in an internal combustion engine. The cutting part 6 of continuously cutting the lining layer 42 in a tapered shape or a curved shape from a back plate 41 part in a longer range than the peripheral direction in the axial direction on which stress intensively acts, or the exposure part of exposing the back plate 41 part by eliminating the lining layer 42, is formed around an oil hole 5 formed in a proper place of the connecting rod bearing 4. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a structure of an oil hole formed in a connecting rod bearing interposed between a crankshaft and a connecting rod of an internal combustion engine.

2. Description of the Related Art Conventionally, a pair of half-broken connecting rod bearings are interposed between a crankshaft and a connecting rod of an internal combustion engine. The connecting rod bearing includes a backing metal and a lining layer laminated on the inside of the backing metal. It consists of and. An oil hole for injecting lubricating oil to the piston side is formed at an appropriate position of the connecting rod bearing, and the lining layer side is chamfered around the oil hole (see, for example, Patent Document 1). .)
JP-A-8-269768

  However, since the tensile stress acts around the oil hole due to the explosive load or rotational load during operation, micro cracks occur around the oil hole, and the low-strength lining layer particularly cracks around the oil hole. It was the starting point.

  And although the location where this crack occurs is roughly determined by its structure, in the above conventional method, only a chamfer around the oil hole is evenly chamfered. As a result, there is a high possibility that a microcrack is generated at the above-mentioned part. As a result, the lining layer at this part is peeled off, resulting in problems such as seizure of the bearing.

  The present invention has been made in view of the above-mentioned problems, and the object of the present invention is to form the oil hole by forming a cutting part and an exposed part in advance in a part where micro cracks around the oil hole are likely to occur. An object of the present invention is to provide an oil hole structure for a connecting rod bearing that can prevent peeling of the lining layer around it and prevent occurrence of defects such as seizure of the bearing due to the peeling.

  In order to achieve the above object, the oil hole structure of the connecting rod bearing of the present invention has a half cracked connecting rod bearing that is interposed between a crankshaft and a connecting rod of an internal combustion engine and a lining layer is laminated on a back metal. In this case, a cutting portion obtained by cutting the lining layer in a taper shape or a curved shape from the back metal portion in a range longer than the circumferential direction in the axial direction of the crankshaft around the oil hole formed at a proper position of the connecting rod bearing. Is formed.

  By previously forming a cutting portion around the oil hole formed in the connecting rod bearing in this manner, the lining layer around the oil hole that is easily peeled off within a certain range without impairing the function as the bearing is deleted in advance. This prevents the lining layer from peeling off at this site.

  Further, the oil hole structure of the connecting rod bearing of the present invention is a half cracked connecting rod bearing interposed between the crankshaft and the connecting rod of the internal combustion engine and having a lining layer laminated on the back metal. An exposed portion formed by removing the lining layer from the back metal portion and exposing the back metal is formed around the oil hole formed in the above. More specifically, the exposed portion is formed in a range longer than the circumferential direction in the axial direction of the crankshaft.

  By previously forming an exposed portion around the oil hole formed in the connecting rod bearing in this manner, the lining layer around the oil hole that is easily peeled off within a certain range that does not impair the function as the bearing is deleted in advance. This prevents the lining layer from peeling off at this site.

  In this invention, it is preferable to form the said cutting part or exposed part in the range longer than the circumferential direction in the axial direction which stress concentrates among the circumference | surroundings of an oil hole. In this way, by forming the cutting part or the exposed part at the site where the stress around the oil hole is concentrated, it is possible to suppress a decrease in the pressure receiving area as the bearing, and thus the formation of the oil film on the bearing may be hindered. Disappear.

  In the present invention, it is preferable that the oil hole is formed in, for example, both end portions of the connecting rod bearing, and the cutting portion or the exposed portion is formed in an elliptical shape when viewed from the inside.

  According to the present invention, the cutting in which the lining layer is cut in a taper shape or a curved shape from the back metal portion around the oil hole formed in the connecting rod bearing in a range longer than the circumferential direction in the axial direction of the crankshaft. By removing the part or the lining layer and forming the exposed part where the back metal is exposed, the peeling of the lining layer due to stress concentration during operation is prevented, and the occurrence of defects such as seizure due to this peeling is prevented. Can do.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a V-type engine as an example of an internal combustion engine, in which a piston 1 and a crankshaft 2 are connected by a connecting rod 3.

  Specifically, as shown in FIG. 2, the upper end portion of the connecting rod 3 is connected to the piston 1 by the piston pin 11, and the lower end portion of the connecting rod 3 is connected to the crankshaft 2 via the connecting rod bearing 4. ing.

  As shown in FIGS. 2 and 3, the connecting rod bearing 4 is formed in a semicircular and half-cracked shape, and is interposed between the crankshaft 2 and the connecting rod 3 as described above in a pair of upper and lower sides. Yes.

  As shown in FIG. 5, the connecting rod bearing 4 includes a backing metal 41 and a lining layer 42 laminated on the inner surface of the backing metal 41 that is on the sliding surface side of the crankshaft 2. For example, the upper connecting rod bearing 4 Oil holes 5 are respectively formed at both ends of the. For example, when the thickness of the back metal 41 is 2 mm, the thickness of the lining layer 42 is about 0.3 mm.

  The oil hole 5 is formed to inject lubricating oil from the crankshaft 2 side to the piston 1 side, and the lubricating oil supplied through the shaft portion of the crankshaft 2 corresponds to the oil hole 5 from the oil hole 5. And it is made to inject to the piston 1 through the injection hole 31 (refer FIG. 2) formed in the lower end part of the connecting rod 3. FIG.

  By the way, as shown in FIG. 4, the oil hole 5 forms the cutting part 6 around it.

  The cutting part 6 is formed in an elliptical shape that is long in the axial direction of the crankshaft 2 (width direction of the connecting rod bearing 4) when viewed from the inside front, and the cross-sectional shape thereof is a back metal around the oil hole 5 as shown in FIG. It is formed by cutting in a tapered manner from the surface portion 41 to the surface of the lining layer 42.

  The axial length of the cutting portion 6 is preferably set to be in a range of 1.5D to 2D, where D is the diameter of the oil hole, and the circumferential length of the cutting portion 6 is If the diameter of the oil hole is D, it is preferably set to be in the range of 1.0D to 1.3D. If the length of the cutting part 6 in the axial direction is 1.5 D or less, as will be described later, since the portion where the stress is concentrated is not sufficiently deleted, no effect can be expected, and cracks can be seen. If the axial length of the portion 6 is 2D or more, the cutting portion 6 becomes too large, the pressure receiving area as a bearing is reduced, and formation of an oil film on the bearing is hindered, leading to occurrence of defects such as seizure. It is.

  Further, the surface roughness of the cutting portion 6 is preferably as small as possible (for example, 1.2 μm RZ or less) so that stress is not concentrated.

  Further, the positions of the oil holes at both ends of the connecting rod bearing 4 are specifically set within a range of, for example, an angle θ = 12 ° ± about 2 °, where θ is an angle with respect to the center as shown in FIG. is doing. The range of the angle θ may be set as appropriate so that the lubricating oil injection capability is suitably obtained according to the type of the internal combustion engine.

  In this way, by forming the cutting portion 6 at the site where the stress around the oil hole 5 is concentrated, the lining layer is peeled off due to the stress concentration during operation, as compared with the conventional case where the chamfer is simply formed. It is possible to prevent the occurrence of defects such as baking due to this peeling. That is, the oil hole 5 is easily peeled within a certain range (the axial length is 1.5D to 2D and the circumferential length is 1.0D to 1.3D) without impairing the function as a bearing. By removing the surrounding lining layer 42 in advance, peeling of the lining layer 42 at this portion is prevented.

  Here, as shown in FIG. 4, the cutting part 6 is hardly formed in the circumferential direction, but the cutting part 6 is formed in the axial direction in which the stress around the oil hole 5 is concentrated. Since the reduction of the area can be suppressed, the formation of the oil film on the bearing is not hindered even if the cutting portion 6 is formed.

  In addition, you may form the cross-sectional shape of the cutting part 6 so that it may continue in a curve as shown in FIG. 6, and there exists an effect similar to what was formed in the above-mentioned taper shape by this.

  Further, although the description has been given of the cutting portion 6 formed in an elliptical shape when viewed from the inside front, it is not necessarily limited to the elliptical shape, and is formed longer than the circumferential direction in the axial direction in which stress concentrates and acts at least from the back metal 41 portion. Any shape can be used.

  Next, FIG. 7 shows another embodiment of the oil hole structure of the connecting rod bearing of the present invention. In this oil hole structure, an exposed portion 7 is formed around the oil hole 5 formed in the same manner as described above.

  The exposed portion 7 is formed in an elliptical shape that is long in the axial direction of the crankshaft 2 (the width direction of the connecting rod bearing 4) as in the case of the cutting portion 6, and its cross-sectional shape is the periphery of the oil hole 5 as shown in FIG. The lining layer 42 is removed so that the surface 41a of the back metal 41 is exposed.

  Further, the length in the axial direction and the length in the circumferential direction of the exposed portion 7 may be set in the same manner as the cutting portion 6.

  Thus, even if the exposed portion 7 is formed around the oil hole 5, the same effect as in the case where the above-described cutting portion 6 is formed can be obtained.

  Here, in the structure of FIG. 7, the exposed portion 7 is formed in the axial direction in which stress around the oil hole 5 is concentrated without forming the exposed portion 7 in the circumferential direction. Therefore, even if the exposed portion 7 is formed, the formation of the oil film on the bearing is not hindered.

  In the above example, the exposed portion 7 is formed in an elliptical shape when viewed from the inside front. However, the exposed portion 7 is not limited to the elliptical shape, and is not limited to the elliptical shape. The shape formed longer than the direction may be sufficient, or the shape which formed the exposed part 7 in circular shape seeing from the inner front may be sufficient.

  Here, the above-described embodiment is merely a preferred embodiment of the present invention, and the present invention is not limited to this, and various design changes can be made within the scope thereof.

  For example, although a V-type engine is shown as an internal combustion engine, the present invention can be applied to other types of engines.

It is a perspective view for showing a connection structure of a piston and a crankshaft in a V type engine as an example of an internal combustion engine. It is a front view which shows the connecting rod which connects a piston and a crankshaft. It is a perspective view which shows a connecting rod bearing. It is the figure which looked at the cutting part formed in the circumference | surroundings of an oil hole from the front. It is AA sectional drawing of FIG. 4 which similarly shows a cutting part. It is sectional drawing which shows the other example of the cutting part. It is sectional drawing which shows an exposed part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Piston 2 Crankshaft 3 Connecting rod 4 Connecting rod bearing 41 Back metal 42 Lining layer 5 Oil hole 6 Cutting part 7 Exposed part

Claims (6)

In a semi-cracked connecting rod bearing that is interposed between a crankshaft of an internal combustion engine and a connecting rod, and a lining layer is laminated on the back metal,
Around the oil hole formed at a suitable position of the connecting rod bearing, a cutting part is formed by cutting the lining layer in a taper shape or a curved shape from the back metal part in a range longer than the circumferential direction in the axial direction of the crankshaft. An oil hole structure of a connecting rod bearing characterized by being made. In a semi-cracked connecting rod bearing that is interposed between a crankshaft of an internal combustion engine and a connecting rod, and a lining layer is laminated on the back metal,
An oil hole structure for a connecting rod bearing, wherein an exposed portion formed by removing the lining layer from the back metal part and exposing the back metal is formed around an oil hole formed in a proper position of the connecting rod bearing.   3. The oil hole structure of a connecting rod bearing according to claim 2, wherein the exposed portion is formed in a range longer than the circumferential direction in the axial direction of the crankshaft.   4. The oil hole structure of a connecting rod bearing according to claim 1, wherein the cut portion or the exposed portion is formed in a range longer than the circumferential direction in an axial direction in which stress is concentrated.   5. The oil hole structure for a connecting rod bearing according to claim 1, wherein the oil holes are formed at both ends of the connecting rod bearing.   6. The oil hole structure of a connecting rod bearing according to claim 1, wherein the cutting part or the exposed part is formed in an elliptical shape when viewed from the inside.

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