JP2011133001A - Half bearing for crankshaft of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a half bearing for a crankshaft of an internal combustion engine which is excellent in embedding performance of foreign matter which accompanies an oil and is mixed therein. <P>SOLUTION: In an inner peripheral surface in the vicinity of peripheral end 7 of a lower half bearing 3 which is a relative rotation tip side of a crankshaft 20 with respect to an oil groove 4 in an upper half bearing 2, a groove depth of a peripheral groove 6 is gradually deepened toward the relative rotation tip side of the crankshaft 20. Foreign matter in the vicinity of the peripheral ends 7 of inner peripheral surfaces of the half bearings 2, 3 is forced to flow to the relative rotation tip side of the crankshaft 20 in which the depth of the peripheral groove 6 is deeper without being pressed in the bottom of the peripheral groove 6. Therefore, a part in which a large amount of foreign matter is locally embedded is hardly formed in the vicinity of the peripheral ends 7 of inner peripheral surfaces of the half bearings 2, 3. As a result, foreign matter can be embedded so as to be dispersed in the peripheral groove 6 accommodating a soft bearing material 8. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention is a half bearing for a crankshaft of an internal combustion engine, which is formed of a steel back metal layer and a bearing alloy layer and is formed in a half shape that combines two to form a cylindrical shape. A plurality of circumferential grooves are formed alternately on the inner circumferential surface of the bearing alloy layer in the axial direction and extend over substantially the entire circumference in the circumferential direction. The present invention relates to a half bearing for a crankshaft of an internal combustion engine formed by accommodating a bearing material and having a sliding surface that is flush with the surface.

  2. Description of the Related Art Conventionally, a crankshaft plain bearing for an internal combustion engine is a cylindrical bearing combined with a pair of half bearings. An oil groove extending in the circumferential direction of the half bearing is formed on the inner peripheral surface of at least one of the pair of half bearings for the journal portion of the crankshaft (for example, a patent Reference 1).

  The oil supply to the crankshaft slide bearing of the internal combustion engine described above was first formed on the inner peripheral surface through a supply hole formed in the upper half bearing from the outside of the crankshaft journal bearing. The oil is supplied into the oil groove, and the oil is supplied to the sliding surface of the journal bearing of the crankshaft and the sliding surface of the crankpin. At this time, it is known that in the initial operation of the internal combustion engine, foreign matter remaining in the oil passage is often mixed with the oil supplied to the oil groove of the upper half bearing. Therefore, in such a crankshaft plain bearing for an internal combustion engine, various methods for embedding foreign matter mixed in the inner peripheral surface of the foreign matter-embedded material have been proposed.

  For example, Japanese Patent Application Laid-Open No. 57-144313 (Patent Document 2) discloses a slide bearing made of a steel back metal and a hard bearing alloy, and the inner peripheral surface of the bearing is alternating with the bearing alloy in the axial direction of the bearing. And a plurality of groove-like recesses are formed that extend over substantially the entire inner peripheral surface of the bearing and accommodate the soft bearing material. According to this, hard bearing alloys such as Al-based alloys and Cu-based alloys support the load from the mating shaft, and embed foreign substances mixed in the inner peripheral surface of the slide bearing in soft bearing materials such as white metal and plastic. This prevents the hard bearing alloy from being damaged by foreign matter. Japanese Utility Model Laid-Open No. 2-9326 (Patent Document 3) discloses a slide bearing in which a circumferential groove extending on an inner circumferential surface is formed, and the groove is formed from an opening for supplying oil to a shaft. There has been disclosed a technique in which the groove depth is gradually reduced toward the relative rotation destination side, and a foreign material burying material is formed on the groove bottom, and foreign matters mixed in oil are buried and removed.

JP-A-8-277831 JP-A-57-144313 Japanese Utility Model Publication No. 2-9326

  By the way, foreign matter mixed in the inner peripheral surface of the crankshaft slide bearing of the internal combustion engine is accompanied by the oil flow caused by the rotation of the crankshaft, and flows in the oil groove toward the relative rotation destination side of the crankshaft. When the vicinity of the combination surface of the bearings is reached, the circumferential end surface of the lower half bearing that does not form the oil groove acts as a barrier and floats to the inner peripheral surface side together with the oil. For this reason, the foreign matter is present on the inner peripheral surface of the slide bearing near the circumferential end of the oil groove on the front side in the relative rotation direction of the crankshaft, particularly in the vicinity of the circumferential end surface of the lower half bearing on the front side of the oil groove. Easily mixed into the peripheral surface. That is, in Patent Document 2, a hard bearing alloy is not embedded in the inner peripheral surface near the circumferential end surface of the lower half bearing of the oil groove front side, and a groove shape containing a soft bearing material. Foreign matter is concentrated and buried in the recess. The foreign matter is pushed into the soft bearing material by the surface of the crankshaft, but is not completely buried in the soft bearing material, but is exposed to the inner peripheral surface side of the slide bearing and comes into contact with the surface of the crankshaft. It is in an easy state. For this reason, heat generated by contact with the surface of the crankshaft is large in the buried portion where many foreign substances are locally buried on the inner peripheral surface side of the slide bearing. When the soft bearing material softens and melts and reaches the allowable limit, many foreign substances buried in the buried part are simultaneously sent to the center of the slide bearing in the circumferential direction, causing seizure of the slide bearing. Cheap.

  Further, in Patent Document 3, foreign substances are likely to be concentrated and embedded in the foreign material-embedding material in a portion where the groove depth on the relative rotation destination side of the crankshaft is shallow. Also in this case, when the soft bearing material softens and melts and reaches the allowable limit in the buried portion where many foreign matters are locally buried, the buried portion is buried in the buried portion. Since many foreign substances are simultaneously sent to the center side in the circumferential direction of the slide bearing, seizure of the slide bearing is likely to occur. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a half bearing for a crankshaft of an internal combustion engine excellent in the burying property of foreign matters accompanying and mixed with oil. It is in.

  In order to achieve the above-mentioned object, in the invention according to claim 1, the crank of the internal combustion engine which is formed of a steel back metal layer and a bearing alloy layer and is formed in a half shape which is a combination of two and forms a cylindrical shape. A shaft half bearing, on the inner circumferential surface of the half bearing, a plurality of bearings arranged alternately with a bearing alloy of the bearing alloy layer in the axial direction and extending over substantially the entire circumference in the circumferential direction. In a half bearing for a crankshaft of an internal combustion engine formed with a circumferential groove and a soft bearing material accommodated in the circumferential groove so that the sliding surface is flush with the circumferential groove, the circumferential groove The depth is minimum at both ends in the circumferential direction of the inner peripheral surface of the half bearing, and the depth is gradually formed deeper toward the center in the circumferential direction of the inner peripheral surface of the half bearing.

  According to a second aspect of the present invention, in the half bearing for a crankshaft of the internal combustion engine according to the first aspect, the width of the circumferential groove is the smallest at both circumferential ends of the inner circumferential surface of the half bearing. The halved bearing is formed so as to gradually become wider toward the central portion in the circumferential direction of the inner peripheral surface of the half bearing.

  According to a third aspect of the present invention, in the half bearing for a crankshaft of an internal combustion engine according to the first or second aspect, a crush relief is provided at both circumferential ends of the inner peripheral surface of the half bearing. It is formed.

  According to a fourth aspect of the present invention, in the half bearing for a crankshaft of the internal combustion engine according to the third aspect, the crush relief surface is provided with a region where the circumferential groove is not formed.

  In the invention according to claim 1, the depth of the circumferential groove is minimized at both circumferential ends of the inner circumferential surface of the half bearing, and gradually becomes deeper toward the circumferential central portion of the inner circumferential surface of the half bearing. Is formed. For this reason, even if a foreign matter larger than the depth of the circumferential groove contacts the bottom surface of the circumferential groove near the circumferential end of the inner circumferential surface of the half bearing, it rotates on the inner circumferential surface side of the half bearing. Due to the force caused by contact between the surface of the crankshaft and the foreign matter, the foreign matter is not pushed into the bottom surface of the circumferential groove, and the relative rotation destination side of the crankshaft with the deeper circumferential groove (the inner circumference of the half bearing) To the circumferential center of the surface). Therefore, it is difficult to form a large amount of a foreign material buried portion in the vicinity of the circumferential end of the inner circumferential surface of the half bearing, and the foreign material is buried in the circumferential groove that contains the soft bearing material. Can do.

  In the invention according to claim 2, the width of the circumferential groove is minimized at both ends in the circumferential direction of the inner circumferential surface of the half bearing, and gradually toward the central portion in the circumferential direction of the inner circumferential surface of the half bearing. Widely formed. For this reason, the foreign material is buried when foreign material is swept away to the relative rotation destination side of the crankshaft where the cross-sectional area of the circumferential groove is wide toward the relative rotation destination side of the crankshaft and the circumferential groove is deeper. Tolerance increases. Therefore, it can disperse | distribute to the circumferential groove | channel which accommodated the soft bearing material, and can embed a foreign material.

  Moreover, in the invention which concerns on Claim 3, the crush relief is formed in the circumferential direction both ends of the internal peripheral surface of a half bearing. According to this, by separating the inner peripheral surface (crash relief surface) at the circumferential end of the half bearing from the surface of the crankshaft, the oil groove of the half bearing flows to the relative rotation destination side of the crankshaft. The ratio of foreign matter discharged to the end portion in the axial direction of the half bearing through the gap between the crash relief surface and the surface of the crankshaft increases. That is, the ratio of foreign matter mixed in the vicinity of the circumferential end of the inner peripheral surface of the half bearing that does not form an oil groove is reduced. In this case, the depth of the circumferential groove is the relative rotation destination side of the crankshaft. By forming a plurality of circumferential grooves on the inner circumferential surface of the half bearing so as to become gradually deeper toward the surface, it is possible to further prevent foreign matter from being embedded locally in the circumferential grooves containing soft metal materials. it can.

  Furthermore, in the invention which concerns on Claim 4, the non-formation area | region of the circumferential groove | channel is provided in the crush relief surface. According to this, foreign matter is most likely to be mixed into the inner peripheral surface at the circumferential end of the half bearing (half bearing that does not form an oil groove) on the tip side of the oil groove, but a circumferential groove is formed at this part. By not doing so, foreign matter is not buried in this part, and the ratio of foreign matter discharged to the axial end portion of the half bearing through the gap between the crash relief surface and the surface of the crankshaft increases. That is, the ratio of foreign matter mixed in the vicinity of the circumferential end 7 on the inner circumferential surface of the lower half bearing 3 where the oil groove 4 is not formed is reduced. By forming a plurality of circumferential grooves 6 on the inner peripheral surface of the lower half bearing 3 so as to gradually become deeper toward the relative rotation destination side of the shaft 20, the circumferential grooves 6 further accommodating the soft metal material 8 are formed. Foreign matter can be made difficult to be buried locally.

FIG. 4 is a side view (A) of a plain bearing composed of two upper half bearings and a lower half bearing that support a crankshaft, and a plan view (B) of the upper half bearing and the lower half bearing. It is a side view of the half bearing which shows the relationship between the internal peripheral surface of a half bearing and the bottom face of a circumferential groove | channel. It is sectional drawing which shows the structure of the internal peripheral surface of a half bearing. It is a top view of the lower half bearing by which the width | variety of the circumferential groove | channel is formed gradually toward the circumferential center part from the circumferential direction edge part of the internal peripheral surface of a lower half bearing. It is the side view (A) of the slide bearing in which the crush relief is formed in the circumferential direction both ends of the internal peripheral surface of a half bearing, and the top view (B) of an upper half bearing and a lower half bearing. It is a top view of the lower half bearing which has provided the non-formation area | region of the circumferential groove | channel in the crush relief surface. It is a side view of the half bearing for demonstrating the range of the non-formation area | region of the circumferential groove | channel in a crush relief surface.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 is a side view (A) of a plain bearing 1 including two upper half bearings 2 and a lower half bearing 3 that support a crankshaft 20, and a plan view of the upper half bearing 2 and the lower half bearing 3. FIG. 2 is a side view of the half bearings 2 and 3 showing the relationship between the inner circumferential surfaces of the half bearings 2 and 3 and the bottom surface of the circumferential groove 6, and FIG. 3 is a cross-sectional view showing the structure of the inner peripheral surface of bearings 2 and 3. FIG. In addition, the above-mentioned figure is the schematic of the slide bearing 1 which concerns on embodiment, and in order to make it easy to understand a structure, a structure, etc., each location is drawn exaggerating or abbreviate | omitting.

  First, a first embodiment corresponding to the invention according to claim 1 will be described with reference to FIG. As shown in FIG. 1 (A), a plain bearing 1 according to this embodiment is formed into a cylindrical shape by combining two half bearings 2 and 3 formed in a half shape, and a crank of an internal combustion engine. The shaft 20 is rotatably supported. In order to satisfy the bearing characteristics of the half bearings 2 and 3 such as seizure resistance, for example, a bearing alloy layer 10 is lined on the steel back metal layer 9 on the inner peripheral surface of the half bearings 2 and 3 (see FIG. 3), overlays such as a summary alloy and a synthetic resin are applied as necessary. The bearing alloy layer 10 may be a known bearing alloy such as an Al alloy or a Cu alloy.

  Further, as shown in FIG. 1 (B), the half bearings 2 and 3 and the half bearings 2 and 3 are supported on the inner peripheral surface of the upper half bearing 2 among the half bearings 2 and 3. An oil groove 4 for supplying lubricating oil between the crankshaft 20 and the crankshaft 20 is formed substantially at the center in the axial direction (width direction) over the entire circumference. In addition, an oil hole 5 for receiving the supply of oil from the outside is formed in substantially the center of the oil groove 4 so as to penetrate in the radial direction of the upper half bearing 2.

  A plurality of circumferential grooves 6 formed in a rectangular shape (see FIG. 3) are alternately arranged on the inner peripheral surfaces of the half bearings 2 and 3 with the bearing alloy of the bearing alloy layer 10 in the axial direction. In addition, it is formed so as to extend over the entire circumference in the circumferential direction. The plurality of circumferential grooves 6 are formed so that the sliding surfaces are flush with each other by containing (filling) the soft bearing material 8. As the soft bearing material 8, a known soft bearing material such as Sn or Sn alloy, Pb or Pb alloy, Bi or Bi alloy, or a sliding resin composition can be applied.

  Thus, the supply of oil to the slide bearing 1 of the crankshaft 20 of the internal combustion engine is first formed on the inner peripheral surface through the oil hole 5 formed in the upper half bearing 2 from the outside of the slide bearing 1. The oil is supplied into the oil groove 4, and the oil is supplied to the sliding surface of the slide bearing 1. At this time, in the initial operation of the internal combustion engine, the foreign matter remaining in the oil passage is often mixed with the oil supplied to the oil groove 4 of the upper half bearing 2. This foreign matter accompanies the oil flow caused by the rotation of the crankshaft 20 and flows in the oil groove 4 to the front side in the relative rotational direction of the crankshaft 20, but in the vicinity of the circumferential end 7 of the half bearings 2 and 3. When it reaches, the circumferential end 7 of the lower half bearing 3 that does not form the oil groove 4 acts as a barrier and floats to the inner peripheral surface side together with the oil. For this reason, the foreign matter is the inner peripheral surface of the slide bearing 1 in the vicinity of the end of the oil groove 4 on the front side in the relative rotational direction of the crankshaft 20, in particular, the peripheral end of the lower half bearing 3 on the front side of the oil groove 4. 7 is easily embedded in the circumferential groove 6 containing the soft bearing material 8 formed on the inner peripheral surface.

  Next, the circumferential groove 6 constituting the main part of the present invention will be described with reference to FIG. As shown in FIG. 2, the center O ′ of the arc that forms the bottom surface of the circumferential groove 6 containing the soft bearing material 8 is the center of the half bearings 2, 3 on the vertical center line of the half bearings 2, 3. The position O is eccentric to the inner peripheral surface side of the half bearings 2 and 3. The radius R2 of the arc that forms the bottom surface of the circumferential groove 6 that accommodates the soft bearing material 8 is slightly longer than the radius R1 of the arc that forms the inner peripheral surfaces of the half bearings 2 and 3. For this reason, the depth of the circumferential groove 6 is minimized at both circumferential end portions 7 of the inner peripheral surfaces of the half bearings 2 and 3, and toward the central portion in the circumferential direction of the inner peripheral surfaces of the half bearings 2 and 3. It is gradually formed deeper.

  By the way, the foreign matter is pushed into the soft bearing material 8 in the circumferential groove 6 by the surface of the crankshaft 20, but when the depth of the circumferential groove 6 is constant or the depth of the circumferential groove 6 is changed to the crank When the depth gradually decreases toward the relative rotation destination side of the shaft 20, foreign substances are concentrated locally and buried. When the size of the foreign material is larger than the depth of the circumferential groove 6, the foreign material is pushed into the bearing alloy on the bottom surface of the circumferential groove 6 by the surface of the rotating crankshaft 20, and moves toward the relative rotation destination side of the crankshaft 20. Cannot move. And this foreign material becomes an obstacle of another foreign material mixed in later, and the foreign material is buried in the part one after another.

  However, according to the present invention, the circumferential groove 6 is formed on the inner circumferential surface in the vicinity of the circumferential end 7 of the lower half bearing 3, which is on the relative rotation destination side of the crankshaft 20 with respect to the oil groove 4 of the upper half bearing 2. The groove depth gradually increases toward the relative rotation destination side of the crankshaft 20. For this reason, even if a foreign matter larger than the circumferential groove 6 is in contact with the bottom surface of the circumferential groove 6 near the circumferential end 7 on the inner circumferential surface of the half bearings 2, 3, Due to the force caused by the contact between the surface of the crankshaft 20 rotating on the inner peripheral surface side and the foreign matter, the foreign matter is not pushed into the bottom surface of the circumferential groove 6 and the crankshaft 20 has a deeper depth. It is swept away to the relative rotation destination side (the central portion side in the circumferential direction of the inner peripheral surfaces of the half bearings 2 and 3). Accordingly, it is difficult to form a large portion of a foreign material buried portion in the vicinity of the circumferential end 7 on the inner circumferential surface of the half bearings 2, 3, and it is dispersed in the circumferential groove 6 containing the soft bearing material 8. Foreign matter can be buried.

  As shown in FIG. 2, if the half bearings 2 and 3 are symmetrical with respect to the center line, the circumferential grooves are always provided when the pair of half bearings 2 and 3 are assembled to the internal combustion engine. The groove depth 6 is minimum at the circumferential end portions 7 of the inner peripheral surfaces of the half bearings 2 and 3, and becomes gradually deeper toward the relative rotation destination side of the crankshaft 20. For this reason, even if the left and right of the half bearings 2 and 3 are mistakenly assembled to the internal combustion engine, the effect of the present invention can be obtained.

  As shown in FIG. 3, the depth D of the circumferential groove 6 is 0.005 to 0.020 mm at the circumferential end 7 of the half bearings 2 and 3, and the circumferential center of the half bearings 2 and 3. Is set to 0.020 to 0.040 mm at the center, and is minimized at both circumferential end portions 7 of the inner peripheral surfaces of the half bearings 2 and 3, and toward the center in the circumferential direction of the inner peripheral surfaces of the half bearings 2 and 3. It is preferable that the groove depth per unit circumferential angle is gradually increased so as to increase by 3% or more. Thus, the depth D of the circumferential groove 6 at the circumferential end 7 of the half bearings 2 and 3 is 0.005 mm or more, and the depth D of the circumferential groove at the circumferential central portion of the half bearings 2 and 3. Is set to 0.020 mm or more, foreign matter is difficult to be pushed into the bearing alloy on the bottom surface of the circumferential groove 6, and the circumferential groove 6 is pushed toward the relative rotation destination side of the crankshaft 20 having a deeper depth. It becomes difficult to form a local buried portion of a large amount of foreign matter. Further, as a method of accommodating the soft metal material 8 in the circumferential groove 6, it is performed by general electroplating. However, if the depth D of the circumferential groove 6 is excessively deep, it is necessary to perform electroplating. Longer time reduces productivity. For this reason, it is preferable to set it to 0.040 mm or less in the center part of the circumferential direction of the half bearings 2 and 3 where the depth D of the circumferential groove 6 is maximum.

  As shown in FIG. 3, the groove width W of the circumferential groove 6 is preferably set to 0.08 to 0.12 mm. Moreover, it is preferable to set the pitch (inter-groove distance) of the circumferential grooves 6 in the axial direction of the half bearing 6 to about 0.1 to 0.3 mm. Further, the exposure rate of the bearing alloy on the inner peripheral surfaces of the half bearings 2 and 3 is preferably set to 5 to 30%. The inner peripheral surfaces of the half bearings 2 and 3 accommodate the hard bearing alloy that mainly supports the load from the crankshaft 20 in the axial direction of the half bearings 2 and 3 and the soft bearing material 8. The circumferential grooves 6 are alternately arranged, and the groove width W and pitch of the circumferential grooves 6 are related to the load capacity of the half bearings 2 and 3. You only have to set it.

  Moreover, in this embodiment, although the rectangular groove | channel was shown as an example as the cross-sectional shape of the circumferential groove | channel 6, it is not limited to this, For example, the reverse which performed chamfering on the both sides of the axial direction of the circumferential groove | channel 6 A trapezoidal shape or other shapes may be used.

  As described above, the circumferential groove 6 formed in the half bearings 2 and 3 according to the first embodiment has a constant groove width. Next, an embodiment corresponding to the invention according to claim 2 will be described. Now, a second embodiment in which the half-width bearings 2 and 3 are formed in a shape in which the groove width of the circumferential groove 6 is different from that of the first embodiment will be described with reference to FIG. FIG. 4 is a plan view of the lower half bearing 3 in which the groove width of the circumferential groove 6 is gradually increased from the circumferential end 7 on the inner circumferential surface of the lower half bearing 3 toward the center in the circumferential direction. is there. 4 shows the lower half bearing 3 of the half bearings 2 and 3 as an example, but the upper half bearing 2 is also provided with a circumferential groove 6 having the same shape as the lower half bearing 3. Yes. Moreover, the same code | symbol as 1st Embodiment is attached | subjected about the member which show | plays the same function as 1st Embodiment.

  The inner circumferential surfaces of the half bearings 2 and 3 according to the second embodiment are formed in the same manner as the first embodiment with respect to the depth of the circumferential groove 6, but as shown in FIG. The groove width 6 is the smallest at both ends 7 in the circumferential direction of the inner peripheral surfaces of the half bearings 2 and 3, and is gradually formed wider toward the center in the circumferential direction of the inner peripheral surfaces of the half bearings 2 and 3. For this reason, when the foreign material is pushed away to the relative rotation destination side of the crankshaft 20, the cross-sectional area of the circumferential groove 6 is wide toward the relative rotation destination side of the crankshaft 20 and the depth of the circumferential groove 6 is deeper. Increases the amount of foreign material to be buried. Therefore, it can disperse | distribute to the circumferential groove | channel 6 which accommodated the soft bearing material 8, and can embed a foreign material.

  Next, it is an embodiment corresponding to the invention according to claim 3, and the half bearings 2, 3 in which the circumferential groove 6 according to the first embodiment is formed are further included in the half bearings 2, 3. A third embodiment in which crush reliefs 11 are formed at both circumferential ends 7 of the peripheral surface will be described with reference to FIG. FIG. 5 is a side view (A) of a slide bearing in which a crush relief is formed at both circumferential ends of the inner peripheral surface of the half bearing, and a plan view (B) of an upper half bearing and a lower half bearing. is there. In addition, about the member which show | plays the same function as 1st Embodiment, the code | symbol same as 1st Embodiment is attached | subjected. Moreover, although 3rd Embodiment shows the example which forms the crush relief 11 with respect to the half bearings 2 and 3 in which the circumferential groove | channel 6 of the shape which concerns on 1st Embodiment is formed, it concerns on 2nd Embodiment. The crush relief 11 may be formed on the half bearings 2 and 3 in which the circumferential groove 6 having the shape is formed.

  As shown in FIG. 5, crash reliefs 11 are formed at both circumferential ends 7 of the inner peripheral surfaces of the half bearings 2, 3 according to the third embodiment. The crush relief 11 is a half bearing formed by removing the thickness of a portion of the half bearings 2 and 3 near the circumferential end 7 of the half bearings 2 and 3 on the inner peripheral surface side. A thickness-reduced region having a center of curvature different from the centers of curvature of the inner and outer peripheral surfaces (refer to a region where the thickness is reduced toward the circumferential end 7; SAE J506 (item 3.26, item 6.4 Reference), DIN 1497, as defined in § 3.2). Thus, by separating the inner peripheral surface (crush relief surface 11a) at the circumferential end 7 of the half bearings 2 and 3 from the surface of the crankshaft 20, the oil grooves 4 of the half bearings 2 and 3 are formed. Ratio of foreign matter discharged to the axial ends of the half bearings 2 and 3 through a gap between the crash relief surface 11a and the surface of the crankshaft 20 among foreign matters flowing toward the relative rotation destination side of the crankshaft Will increase. That is, the ratio of foreign matter mixed in the vicinity of the circumferential end 7 on the inner circumferential surface of the lower half bearing 3 where the oil groove 4 is not formed is reduced. By forming a plurality of circumferential grooves 6 on the inner peripheral surface of the lower half bearing 3 so as to gradually become deeper toward the relative rotation destination side of the shaft 20, the circumferential grooves 6 further accommodating the soft metal material 8 are formed. Foreign matter can be made difficult to be buried locally.

  Next, in an embodiment corresponding to the invention according to claim 4, the circumferential groove 6 is further formed in the crush relief surface 11a with respect to the half bearings 2 and 3 in which the crush relief 11 according to the third embodiment is formed. A fourth embodiment in which the non-forming region 12 is formed will be described with reference to FIGS. FIG. 6 is a plan view of the lower half bearing 3 in which the non-formation region 12 of the circumferential groove 6 is provided on the crush relief surface 11a, and FIG. 7 is a non-formation region of the circumferential groove 6 on the crush relief surface 11a. 12 is a side view of the half bearings 2 and 3 for explaining a range of 12; FIG. 6 shows the lower half bearing 3 of the half bearings 2 and 3 as an example, but the upper half bearing 2 also has the circumferential groove 6 in the same manner as the crash relief surface 11a of the lower half bearing 3. A non-forming region 12 is formed. Moreover, the same code | symbol as 3rd Embodiment is attached | subjected about the member which show | plays the same function as 3rd Embodiment.

  As shown in FIG. 6, the non-formation area | region 12 of the circumferential groove | channel 6 is formed in the crush relief surface 11a formed in the circumferential direction both ends 7 of the internal peripheral surface of the half bearings 2 and 3 which concern on 4th Embodiment. Is provided. That is, the groove end of the circumferential groove 6 formed over the circumferential direction of the half bearings 2 and 3 is not formed to the circumferential end 7 of the half bearings 2 and 3. According to this, foreign matter is most likely to be mixed into the inner peripheral surface in the vicinity of the circumferential end 7 of the lower half bearing 3, which is the relative rotation destination side of the crankshaft 20 with respect to the oil groove 4 of the upper half bearing 2. By not forming the circumferential groove 6 in this part, foreign matter is not buried in this part, and the axial direction of the half bearings 2, 3 through the gap between the crush relief surface 11 a and the surface of the crankshaft 20. The ratio of the foreign matter discharged to the end of this increases. That is, the ratio of foreign matter mixed in the vicinity of the circumferential end 7 on the inner circumferential surface of the lower half bearing 3 where the oil groove 4 is not formed is reduced. By forming a plurality of circumferential grooves 6 on the inner peripheral surface of the lower half bearing 3 so as to gradually become deeper toward the relative rotation destination side of the shaft 20, the circumferential grooves 6 further accommodating the soft metal material 8 are formed. Foreign matter can be made difficult to be buried locally.

  In addition, the range of the non-formation region 12 of the circumferential groove 6 on the crush relief surface 11a is such that the circumferential angle θ from the circumferential end 7 of the half bearings 2 and 3 is 1. The range is less than the circumferential angle corresponding to the range in which the crash relief 11 is formed at a maximum of 5 °. In the case where the circumferential angle θ from the circumferential end 7 of the half bearings 2 and 3 is less than 3 °, the effect of discharging foreign matters compared to the case where the non-formation region 12 of the circumferential groove 6 is not formed. There is no difference. Further, the range less than the circumferential angle corresponding to the range in which the crash relief 11 is formed is that the crush relief surface 11a adjacent to the inner circumferential surface of the half bearings 2 and 3 and the surface of the crankshaft 20 This is because there is a possibility that foreign matter may bite into the crash relief surface 11a. That is, by forming the circumferential groove 6 containing the soft metal material 8 in the crush relief surface 11a adjacent to the inner circumferential surface of the half bearings 2 and 3, foreign matter is prevented from biting into the crush relief surface 11a. can do.

  In the first embodiment to the fourth embodiment, the present invention has been described as an example in which the present invention is applied to the half bearings 2 and 3 for the journal portion of the crankshaft 20 of the internal combustion engine. The present invention can also be applied to a half bearing for a pin.

DESCRIPTION OF SYMBOLS 1 Slide bearing 2 Upper half bearing 3 Lower half bearing 4 Oil groove 5 Oil hole 6 Circumferential groove 7 Circumferential end part 8 Soft bearing material 11 Crash relief 11a Crash relief surface 12 Non-formation area | region 20 Crankshaft

Claims (4)

A half bearing for a crankshaft of an internal combustion engine comprising a steel back metal layer and a bearing alloy layer and formed into a half shape comprising a combination of two, and an inner peripheral surface of the half bearing Includes a plurality of circumferential grooves that are arranged alternately with the bearing alloy of the bearing alloy layer in the axial direction and extend over substantially the entire circumference in the circumferential direction, and a soft bearing material is accommodated in the circumferential grooves. In the half bearing for the crankshaft of the internal combustion engine formed so that the sliding surface is flush,
The circumferential groove has a minimum depth at both ends in the circumferential direction of the inner circumferential surface of the half bearing, and is gradually formed deeper toward the circumferential central portion of the inner circumferential surface of the half bearing. A half bearing for a crankshaft of an internal combustion engine that is characterized.   The width of the circumferential groove is minimized at both circumferential ends of the inner circumferential surface of the half bearing, and is gradually formed wider toward the circumferential central portion of the inner circumferential surface of the half bearing. A half bearing for a crankshaft of an internal combustion engine according to claim 1.   The half bearing for a crankshaft of an internal combustion engine according to claim 1 or 2, wherein a crush relief is formed at both circumferential ends of the inner circumferential surface of the half bearing.   4. A half bearing for a crankshaft of an internal combustion engine according to claim 3, wherein the crush relief surface is provided with a region where the circumferential groove is not formed.

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