JP2019100306A - engine - Google Patents

Abstract

To provide an engine which enables improvement of durability of a bearing metal while reducing rotational resistance of a crank shaft.SOLUTION: An engine includes a crank shaft 13 and has: a crank support medium 31 formed with a journal bore 25 which houses a crank journal 21 of the crank shaft 13; and a bearing metal 26 provided between the journal bore 25 and the crank journal 21 housed in the journal bore 25 and including a lining 26b facing the crank journal 21. The journal bore 25 includes: a main bore part 41 formed at an axial center part; and sub bore parts 42 formed at axial end parts. In a radial direction of the crank journal 21, the lining 26b of the bearing metal 26 overlaps with the sub bore parts 42 of the journal bore 25. A reaction force F1 received by the bearing metal 26 from each sub bore part 42 is smaller than a reaction force F2 received by the bearing metal 26 from the main bore part 41.SELECTED DRAWING: Figure 6

Description

  The present invention relates to an engine provided with a crankshaft.

  An engine mounted on an automobile or the like has a cylinder block constituting an engine body and a crankshaft rotatably supported by the cylinder block. A bearing metal, which is a slide bearing, is assembled to the bearing portion of the cylinder block, and a crankshaft is rotatably supported via the bearing metal (see Patent Document 1).

JP, 2016-191433, A

  By the way, since a bending vibration generate | occur | produces in a crankshaft, depending on the generation | occurrence | production condition of a bending vibration, a partial contact will arise in a crankshaft and a bearing metal, and it has become a factor which reduces durability of a bearing metal. Therefore, it is conceivable to suppress the partial contact between the crankshaft and the bearing metal by subjecting the bearing metal to a large chamfering process called crowning process. However, giving a large chamfering process to the bearing metal is a factor to reduce the sliding area of the bearing metal, and is a factor to increase the rotational resistance of the crankshaft.

  An object of the present invention is to improve the durability of a bearing metal while reducing the rotational resistance of a crankshaft.

  The engine according to the present invention is an engine provided with a crankshaft, and between a crank support in which a journal bore for accommodating the crank journal of the crankshaft is formed, the journal bore and the crank journal accommodated therein. And a bearing metal provided with a lining layer facing the crank journal, wherein the journal bore is formed at a widthwise end with a first bore formed at a widthwise center. And the lining layer of the bearing metal overlaps the second bore portion of the journal bore in the radial direction of the crank journal, and the reaction force received by the bearing metal from the second bore portion Is smaller than the reaction force that the bearing metal receives from the first bore portion.

  According to the present invention, in the radial direction of the crank journal, the lining layer of the bearing metal overlaps the second bore portion of the journal bore and the reaction force received by the bearing metal from the second bore portion is the bearing metal in the first bore portion It is smaller than the reaction force received from. Thereby, the durability of the bearing metal can be improved while reducing the rotational resistance of the crankshaft.

FIG. 1 is a schematic view showing an engine according to an embodiment of the present invention. FIG. 1 is an exploded view of an engine showing a cylinder block and a crankshaft. It is an exploded view which shows a bearing structure from the arrow (alpha) direction of FIG. (A) is a front view which shows a bearing structure from the arrow (alpha) direction of FIG. 1, (b) is sectional drawing in alignment with the AA of Fig.4 (a). (A) is a perspective view which shows a part of support wall provided with a bore part, (b) is sectional drawing in alignment with the AA of Fig.5 (a). It is an enlarged view which shows the crank journal shown in FIG.4 (b), and its vicinity. (A) And (b) is an enlarged view which shows a bearing metal when bending vibration generate | occur | produces in a crankshaft, and its vicinity. (A) And (b) is a perspective view which shows the support wall of another example. (A) is a front view which shows the bearing structure with which the engine which is other embodiment of this invention is equipped, (b) is sectional drawing in alignment with the AA of Fig.9 (a). (A) is a perspective view which shows a part of support wall provided with a bore part, (b) is sectional drawing in alignment with the AA of Fig.10 (a). It is an enlarged view which shows the crank journal shown in FIG.9 (b), and its vicinity. (A) And (b) is an enlarged view which shows a bearing metal when bending vibration generate | occur | produces in a crankshaft, and its vicinity. It is a perspective view which shows the support wall of another example.

  Hereinafter, embodiments of the present invention will be described in detail based on the drawings. FIG. 1 is a schematic view showing an engine 10 according to an embodiment of the present invention. FIG. 1 shows the engine 10 with the cylinder head and the like omitted. Although the engine 10 shown in FIG. 1 is a horizontally opposed four-cylinder engine, it is not limited thereto, and may be another type of engine. As shown in FIG. 1, the engine 10 includes a cylinder block 11 constituting one cylinder bank, a cylinder block 12 constituting the other cylinder bank, and a crankshaft 13 supported by a pair of cylinder blocks 11 and 12 ,have.

  FIG. 2 is an exploded view of the engine 10 showing the cylinder blocks 11, 12 and the crankshaft 13. As shown in FIG. As shown in FIG. 2, one cylinder block 11 is formed with two cylinder bores 14 and five support walls 16 provided with semicircular bore portions 15. Similarly, in the other cylinder block 12, two cylinder bores 17 are formed, and five support walls 19 provided with semicircular bore portions 18 are formed. As shown in FIG. 1, the piston 20 is accommodated in the cylinder bores 14 and 17 of the cylinder blocks 11 and 12 so as to be capable of reciprocating.

  The crankshaft 13 includes five crank journals 21 provided at the rotation center C 1 and four crank throws 22 connecting the crank journals 21. Further, each crank throw 22 is provided with a crank pin 23 eccentric to the rotation center C1, and a crank arm 24 connecting the crank journal 21 and the crank pin 23 is provided. As shown in FIG. 1, a journal bore 25 is formed by the bore portions 15, 18 of the cylinder blocks 11, 12 facing each other, and the crank journal 21 is rotatably supported by the journal bore 25 via a bearing metal 26. It is supported. A piston 20 is connected to the crank pin 23 via a connecting rod 27.

[Crankshaft bearing structure]
The bearing structure of the crankshaft 13 will be described. FIG. 3 is an exploded view showing the bearing structure from the direction of arrow α in FIG. 4 (a) is a front view showing the bearing structure from the direction of arrow α in FIG. 1, and FIG. 4 (b) is a cross-sectional view taken along the line AA of FIG. 4 (a). In FIGS. 3 and 4, only the crank journal 21 is shown as the crankshaft 13.

  As shown in FIG. 3, a semicircular bore portion 15 is formed in the support wall 16 of the cylinder block 11, and a semicylindrical bearing metal 26 is assembled to the bore portion 15. Further, a semicircular bore portion 18 is formed in the support wall 19 opposed to the support wall 16, and a semi-cylindrical bearing metal 26 is assembled to the bore portion 18. By sandwiching the crank journal 21 by the support walls 16 and 19 as described above, the crank journal 21 is rotatably supported by the support walls 16 and 19 as shown in FIGS. 4 (a) and 4 (b). The support wall 16 of the cylinder block 11 and the support wall 19 of the cylinder block 12 opposed thereto are fastened by a fastening bolt 30 inserted from the support wall 16 side.

  Thus, the crank support 31 is formed by the support walls 16 and 19, and the journal bore 25 is formed by the bores 15 and 18. A crank journal 21 of the crankshaft 13 is accommodated in a journal bore 25 formed in the crank support 31. Further, a pair of bearing metals 26 constituting a slide bearing is provided between the journal bore 25 and the crank journal 21 accommodated therein. As shown in the enlarged portions of FIGS. 3 and 4B, the bearing metal 26 is a back metal 26a formed in a semi-cylindrical shape using carbon steel or the like, and copper provided on the inner peripheral surface of the back metal 26a. And a lining (lining layer) 26b of an alloy, an aluminum alloy, or the like. That is, the back metal 26 a facing the journal bore 25 is provided on the outer peripheral portion of the bearing metal 26, and the lining 26 b facing the crank journal 21 is provided on the inner peripheral portion of the bearing metal 26. In addition, in order to improve the anti-seizure property, the conformability, etc. of the bearing metal 26, an overlay which is a coating of a lead alloy, a tin alloy, or a resin may be formed on the surface of the lining 26b.

[Journal bore structure]
5 (a) is a perspective view showing a part of the support wall 16 provided with the bore portion 15, and FIG. 5 (b) is a cross-sectional view taken along the line AA of FIG. 5 (a). Further, in FIG. 5A, oil holes and the like formed in the support wall 16 are omitted and illustrated. Although the structure of the bore portion 15 formed in the support wall 16 will be described, the bore portion 18 of the support wall 19 opposed to the support wall 16 also has the same structure.

  As shown in FIGS. 5A and 5B, the bore portion 15 includes a main bore portion 41 formed at the central portion in the width direction and a sub bore portion 42 formed at the end portion in the width direction. That is, the journal bore 25 formed in the pair of support walls 16 and 19 has a main bore portion (first bore portion) 41 formed in the central portion in the width direction and a sub bore portion (second portion) formed in the end portion in the width direction. And 42). As shown in FIG. 5 (b), the main bore portion 41 of the journal bore 25 has an inner circumferential surface 41a parallel to the rotation center C1 of the crank journal 21, and the sub bore portion 42 of the journal bore 25 is a crank journal An inner circumferential surface 42 a is inclined with respect to the rotation center C 1 of 21. That is, the sub bore portion 42 of the journal bore 25 is formed with an inclined inner circumferential surface 42 a, that is, a chamfered portion. The width direction of the journal bore 25 is a direction parallel to the rotation center (central axis) C1 of the crank journal 21. In other words, the width direction of the journal bore 25 is a direction orthogonal to the circumferential direction of the journal bore 25.

  FIG. 6 is an enlarged view showing the crank journal 21 shown in FIG. 4 (b) and the vicinity thereof. As shown in FIG. 6, in the radial direction of the crank journal 21, the lining 26 b of the bearing metal 26 overlaps all of the main bore portion 41 of the journal bore 25. Further, the lining 26 b of the bearing metal 26 overlaps the sub bore portion 42 of the journal bore 25 in the radial direction of the crank journal 21. That is, the width dimension W1 of the lining 26b constituting the bearing metal 26 is set wider than the width dimension W2 of the main bore portion 41 constituting the journal bore 25. Therefore, both widthwise end portions of the lining 26 b of the bearing metal 26 are disposed so as to overlap the subbore portions 42 connected to both widthwise ends of the main bore portion 41. The radial direction of the crank journal 21 is a direction orthogonal to the rotation center (central axis) C1 of the crank journal 21.

  As described above, the journal bore 25 formed in the support walls 16 and 19 as the crank support 31 includes the main bore 41 formed in the center in the width direction and the sub bore 42 formed in the end in the width direction. ,have. As shown in FIG. 6, the main bore portion 41 of the journal bore 25 contacts the back metal 26 a of the bearing metal 26, while the sub bore portion 42 of the journal bore 25 is separated from the back metal 26 a of the bearing metal 26. Therefore, when load Fc is input from crank journal 21 to bearing metal 26, as shown by the solid line arrow, while bearing metal 26 receives reaction force f1 from main bore portion 41, as shown by the broken line arrow. The bearing metal 26 does not receive the reaction force f 2 from the sub bore portion 42. That is, reaction force f 2 received by bearing metal 26 from sub bore portion 42 is smaller than reaction force f 1 received by bearing metal 26 from main bore portion 41. In addition, that the reaction force f2 is smaller than the reaction force f1 means that the load per unit area which the bearing metal 26 receives, that is, the force per unit area is small.

[Crankshaft bending vibration]
During operation of the engine, a centrifugal force due to rotation, a thrust of the piston 20, and the like act on the crankshaft 13, so bending vibration is generated on the crankshaft 13. Here, FIGS. 7A and 7B are enlarged views showing the bearing metal 26 and the vicinity thereof when bending vibration occurs in the crankshaft 13. When bending vibration occurs in the crankshaft 13, the crank journal 21 swings within the journal bore 25. That is, the tilting motion (arrow a1) of the crank journal 21 shown in FIG. 7 (a) and the tilting motion (arrow b1) of the crank journal 21 shown in FIG. 7 (b) are alternately repeated. . As described above, when the crank journal 21 swings within the journal bore 25, one contact of the crank journal 21 and the lining 26 b is induced.

  However, the lining 26 b of the bearing metal 26 is overlapped with the sub bore portion 42 of the journal bore 25 in the radial direction of the crank journal 21. Thus, as shown by arrows a2 and b2 in FIGS. 7A and 7B, the end in the width direction of the bearing metal 26 is pushed toward the journal bore 25 by the deflection of the crank journal 21. Also, since the bearing metal 26 can be released until it contacts the subbore portion 42, excessive contact between the crank journal 21 and the lining 26b can be avoided. That is, the seizure resistance, the wear resistance and the like of the bearing metal 26 can be improved by suppressing the partial contact between the crank journal 21 and the lining 26 b, and the durability of the bearing metal 26 can be improved.

  In addition, since the sub bore portion 42 is formed in the journal bore 25, there is no need to chamfer the bearing metal 26 to prevent partial contact (crowning), and the lining 26 b of the bearing metal 26 can be formed widely. Can. As a result, the sliding area between the crank journal 21 and the lining 26 b can be secured, and the load per unit area received by the lining 26 b from the crank journal 21 can be reduced, so the rotational resistance of the crank journal 21 is reduced. It is possible.

  In the example shown in FIG. 5A, the sub bores 42 are formed at both ends in the width direction of the journal bore 25 and the chamfered portions 42 a are formed over the entire circumference of the sub bore 42, but the present invention is limited thereto. There is nothing to do. Here, FIGS. 8A and 8B are perspective views showing support walls 50 and 51 of another example. As shown in FIG. 8A, as the sub bore portion 42 constituting the journal bore 25 of the support wall 50, the sub bore portion 42 may be formed at one end in the width direction. Further, as shown in FIG. 8B, the chamfered portion 42a may be formed in a plurality of places in the sub bore portion 42 which constitutes the journal bore 25 of the support wall 51. Further, in the example shown in FIG. 6, the main bore portion 41 and the sub bore portion 42 are formed in both of the bore portions 15 and 18, but the present invention is not limited thereto, and the main bore may be formed in only one of the bore portions 15 and 18. The portion 41 and the sub bore portion 42 may be formed.

Other Embodiments
Although the sub bore portion 42 of the journal bore 25 is constituted by the chamfered portion 42 a in the above description, the present invention is not limited to this, and the sub bore portion of another structure may be configured with respect to the journal bore. Subsequently, the sub bore portion 72 of the journal bore 65 provided in the engine according to another embodiment of the present invention will be described. In the following description, the same members as the members shown in FIGS. 1 to 8 described above are denoted by the same reference numerals, and the description thereof is omitted. Here, FIG. 9 (a) is a front view showing a bearing structure provided in an engine according to another embodiment of the present invention, and FIG. 9 (b) is a cross section along line A-A of FIG. 9 (a). FIG. In FIG. 9 (a), the same part as that in FIG. 4 (a) is shown.

  As shown in FIGS. 9A and 9B, a semicircular bore portion 61 is formed in the support wall 60 of the cylinder block 11, and a semicylindrical bearing metal 26 is assembled to the bore portion 61. It is done. Further, a semicircular bore portion 63 is formed in the support wall 62 facing the support wall 60, and a semi-cylindrical bearing metal 26 is assembled to the bore portion 63. The crank journal 21 is rotatably supported by the support walls 60 and 62 by sandwiching the crank journal 21 by the support walls 60 and 62 as described above. Thus, the crank support 64 is formed by the support walls 60 and 62, and the journal bore 65 is formed by the bores 61 and 63. The crank journal 21 of the crankshaft 13 is accommodated in a journal bore 65 formed in the crank support 64. Further, a pair of bearing metals 26 constituting a sliding bearing is provided between the journal bore 65 and the crank journal 21 accommodated therein.

[Journal bore structure]
10 (a) is a perspective view showing a part of the support wall 60 provided with the bore portion 61, and FIG. 10 (b) is a cross-sectional view taken along the line A-A of FIG. 10 (a). Further, in FIG. 10A, oil holes and the like formed in the support wall 60 are omitted. Although the structure of the bore portion 61 of the support wall 60 will be described, the bore portion 63 of the support wall 62 facing the support wall 60 also has a similar structure.

  As shown in FIGS. 10A and 10B, the bore portion 61 includes a main bore portion 71 formed at the central portion in the width direction and a sub bore portion 72 formed at the end portion in the width direction. That is, the journal bores 65 formed in the pair of support walls 60 and 62 have a main bore (first bore) 71 formed at the center in the width direction and a sub bore (second) formed at the end in the width direction. And the bore portion 72). As shown in FIG. 10B, the sub bore portion 72 of the journal bore 65 has a recess 73 on the side. The main bore portion 71 and the sub bore portion 72 of the journal bore 65 have an inner circumferential surface 74 parallel to the rotation center C1 of the crank journal 21.

  FIG. 11 is an enlarged view showing the crank journal 21 shown in FIG. 9 (b) and the vicinity thereof. As shown in FIG. 11, in the radial direction of the crank journal 21, the lining 26 b of the bearing metal 26 overlaps all of the main bore portion 71 of the journal bore 65. Further, the lining 26 b of the bearing metal 26 overlaps the sub bore portion 72 of the journal bore 65 in the radial direction of the crank journal 21. That is, the width dimension W1 of the lining 26b constituting the bearing metal 26 is set wider than the width dimension W2 of the main bore portion 71 constituting the journal bore 65. Therefore, both widthwise end portions of the lining 26 b of the bearing metal 26 are arranged to overlap with the subbore portions 72 connected to both widthwise ends of the main bore portion 71. The radial direction of the crank journal 21 is a direction orthogonal to the rotation center (central axis) C1 of the crank journal 21.

  As described above, the journal bores 65 formed in the support walls 60 and 62 which are the crank supports 64 are the main bore 71 formed in the center in the width direction and the sub bore 72 formed in the end in the width direction ,have. As shown in FIG. 11, since the recess 73 is formed in the sub bore 72 of the journal bore 65, the rigidity of the sub bore 72 is lower than that of the main bore 71. That is, the support piece 75 provided between the concave portion 73 of the sub bore portion 72 and the inner circumferential surface 74 is more easily deformed than the other portion constituting the journal bore 65. Therefore, when load Fc is input from crank journal 21 to bearing metal 26, as shown by the solid arrow, while bearing metal 26 receives reaction force f1 from main bore portion 71, as shown by the dashed arrow. The bearing metal 26 receives a reaction force f 2 smaller than the reaction force f 1 from the sub bore portion 72. That is, the reaction force f 2 received by the bearing metal 26 from the sub bore portion 72 is smaller than the reaction force f 1 received by the bearing metal 26 from the main bore portion 71. In addition, that the reaction force f2 is smaller than the reaction force f1 means that the load per unit area which the bearing metal 26 receives, that is, the force per unit area is small.

[Crankshaft bending vibration]
During operation of the engine, a centrifugal force due to rotation, a thrust of the piston 20, and the like act on the crankshaft 13, so bending vibration is generated on the crankshaft 13. Here, FIGS. 12 (a) and 12 (b) are enlarged views showing the bearing metal 26 and its vicinity when bending vibration occurs in the crankshaft 13. FIG. When bending vibration occurs in the crankshaft 13, the crank journal 21 swings within the journal bore 65. That is, the tilting motion (arrow a1) of the crank journal 21 shown in FIG. 12 (a) and the tilting motion (arrow b1) of the crank journal 21 shown in FIG. 12 (b) are alternately repeated. . As described above, when the crank journal 21 swings in the journal bore 65, one contact of the crank journal 21 and the lining 26b is induced.

  However, the lining 26 b of the bearing metal 26 is overlapped with the sub bore portion 72 of the journal bore 65 in the radial direction of the crank journal 21. As a result, as shown by arrows a2 and b2 in FIGS. 12A and 12B, the end in the width direction of the bearing metal 26 is pushed toward the journal bore 65 by the deflection of the crank journal 21. Also, since the support piece 75 of the sub bore portion 72 can be deformed to release the bearing metal 26, excessive contact between the crank journal 21 and the lining 26b can be avoided. That is, by suppressing the partial contact between the crank journal 21 and the lining 26 b, the seizure resistance, the wear resistance and the like of the bearing metal 26 can be improved, and the durability of the bearing metal 26 can be improved.

  In addition, since the sub bore portion 72 is formed in the journal bore 65, there is no need to perform chamfering (crowning) on the bearing metal 26 in order to suppress partial contact, and the lining 26 b of the bearing metal 26 can be formed widely. Can. As a result, the sliding area between the crank journal 21 and the lining 26 b can be secured, and the load per unit area received by the lining 26 b from the crank journal 21 can be reduced, so the rotational resistance of the crank journal 21 is reduced. It is possible.

  In the example shown in FIG. 10A, the concave portion 73 is partially formed on the side surface of the sub bore portion 72, but the present invention is not limited to this. Here, FIG. 13 is a perspective view showing a support wall 80 of another example. As shown in FIG. 13, with respect to the sub bore portion 72 that constitutes the journal bore 65 of the support wall 80, a recess 81 may be formed on the side surface extending around a half circumference. Further, in the example shown in FIG. 11, the main bore portion 71 and the sub bore portion 72 are formed in both of the bore portions 61 and 63, but the present invention is not limited to this. The portion 71 and the sub bore portion 72 may be formed. Further, in the example shown in FIG. 11, the sub bores 72 are formed at both widthwise end portions of the journal bore 65, but the present invention is not limited to this. You may form

  It is needless to say that the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention. For example, although the horizontally opposed four-cylinder engine is adopted as the engine 10 in the above description, the invention is not limited thereto, and another type of engine in which the number of cylinders and the cylinder arrangement are changed is adopted. good. For example, when the present invention is applied to an in-line engine, the crank journal is rotatably supported by the support wall of the cylinder block and the bearing cap assembled thereto. In this case, the main bore portion and the sub bore portion will be formed in one or both of the support wall and the bearing cap.

10 Engine 13 Crankshaft 21 Crank Journal 25 Journal Bore 26 Bearing Metal 26b Lining (lining layer)
31 crank support 41 main bore (first bore)
42 Sub bore (2nd bore)
42a Inner peripheral surface (Chamfered portion)
64 crank support 65 journal bore 71 main bore (first bore)
72 Sub bore (2nd bore)
f1 reaction force f2 reaction force

Claims (4)

An engine comprising a crankshaft,
A crank support formed with a journal bore for receiving a crank journal of the crank shaft;
A bearing metal provided between the journal bore and the crank journal received therein, the lining layer facing the crank journal;
Have
The journal bore includes a first bore portion formed in a widthwise central portion and a second bore portion formed in a widthwise end portion.
In the radial direction of the crank journal, the lining layer of the bearing metal overlaps the second bore portion of the journal bore;
The reaction force received by the bearing metal from the second bore portion is smaller than the reaction force received by the bearing metal from the first bore portion.
engine. In the engine according to claim 1,
In the radial direction of the crank journal, the lining layer of the bearing metal overlaps all of the first bore portion of the journal bore,
engine. In the engine according to claim 1 or 2,
The second bore portion comprises a chamfer.
engine. In the engine according to claim 1 or 2,
The second bore portion is less rigid than the first bore portion,
engine.

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