JP4840349B2 - Engine bearing lubrication structure - Google Patents

Description

  The present invention relates to an engine bearing oil supply structure, and more particularly to an engine bearing oil supply structure for supplying oil to a bearing that supports a crankshaft.

  Conventionally, in an engine, oil is supplied to a bearing for supporting a crankshaft for lubrication. In this regard, when supplying oil to the bearing of the crankshaft, it is common to forcibly supply oil by an oil pump (see, for example, Patent Document 1 or 2). On the other hand, for example, Patent Document 3 proposes a technique that is considered to be related to the present invention as a technique for supplying oil without forcibly supplying oil. In addition, as a technique related to the bearing peripheral structure of the crankshaft, for example, Patent Document 4 proposes a technique that is considered to be related to the present invention.

Japanese Patent Laid-Open No. 06-50119 Japanese Utility Model Publication No. 04-44413 JP 2005-331105 A JP 2004-84646 A

  By the way, when the rolling bearing is applied to the bearing of the crankshaft, the amount of supply oil leaks more than that when the sliding bearing is applied, and as a result, the hydraulic pressure decreases. In this regard, when oil is forcibly supplied to the bearing of the crankshaft by the oil pump, it is conceivable to increase the capacity of the oil pump in order to suppress a decrease in hydraulic pressure. However, when the capacity of the oil pump is increased, the drive work of the oil pump increases, and as a result of an increase in friction due to an increase in sliding area, the output performance of the engine decreases.

  In addition, when rolling bearings are applied to the bearings of the crankshaft, if the amount of oil supplied to the rolling bearings increases, the rollers or balls of the rolling bearings float in the oil, and as a result, the rollers or balls rotate the bearings. As a resistance to attenuate, friction increases. That is, the original low friction performance of the rolling bearing is not exhibited.

  Accordingly, the present invention has been made in view of the above-described problems, and a small amount of oil can be supplied to the bearing that supports the crankshaft without deteriorating the output performance of the engine. In particular, the bearing is a rolling bearing. An object of the present invention is to provide a bearing oil supply structure for a crankshaft suitable for the case.

In order to solve the above problems, the present invention is an engine bearing oil supply structure for supplying oil to a bearing that supports a crankshaft, and is formed from a cylinder head of the engine toward the bearing direction, An oil inflow portion into which oil supplied to the cylinder head flows, an oil supply passage that branches from the oil inflow portion and supplies oil to the bearing, and a portion of the oil inflow portion where the oil supply passage branches And an oil reservoir formed in a lower portion than the above. According to the present invention, by supplying the oil flowing through the oil inflow portion to the bearing of the crankshaft by dropping its own weight, a small amount of oil can be supplied without performing forced oil supply by the oil pump. Therefore, according to the present invention, a small amount of oil can be supplied to the bearing that supports the crankshaft without reducing the output performance of the engine.
Further, according to the present invention, the oil accumulated in the oil reservoir can be supplied to the bearing of the crankshaft, so that more stable oil can be supplied.

Further, the present invention can be configured to provide a constriction portion that communicates the oil pan of the engine with the oil reservoir and has a flow passage cross-sectional area smaller than that of the oil inflow portion . According to the present invention, by appropriately setting the cross-sectional area of the constricted portion, oil can be stored in the oil inflow portion during engine operation to stably supply oil, and when the engine is stopped, the oil from the oil inflow portion can be supplied. Thus, dust mixed in the oil can be discharged. That is, according to the present invention, Ru can suitably suppress the dust contained in the oil to reach the bearing.

  In the present invention, the oil supply passage may be communicated with a portion of the bearing in front of the maximum load point in the rotation direction of the crankshaft via a bearing holding member that holds the bearing from below. it can. According to the present invention, it is possible to supply oil to a portion of the bearing that has a particularly large oiling effect, and as a result, the bearing can be sufficiently lubricated with a small amount of oil.

  In the present invention, the bearing may be a rolling bearing. That is, the present invention is particularly suitable for a case where a rolling bearing capable of exhibiting low friction performance with a small amount of oil supply is applied to a crankshaft bearing. .

  According to the present invention, even when oil is forcibly supplied to a bearing by an oil pump, a small amount of oil can be supplied to the bearing, and a decrease in hydraulic pressure that occurs when the bearing is a rolling bearing is also suppressed. be able to. For this reason, according to the present invention, a small amount of oil can be supplied to the rolling bearing without particularly increasing the capacity of the oil pump. That is, according to the present invention, a small amount of oil can be supplied to the rolling bearing that supports the crankshaft without degrading the output performance of the engine. Further, according to the present invention, when a rolling bearing and a sliding bearing coexist on a bearing that supports a crankshaft, it is possible to supply oil suitable for each bearing, and at the same time, an oil supply passage dedicated to the rolling bearing. Can be eliminated.

  According to the present invention, a small amount of oil can be supplied to the bearing that supports the crankshaft without degrading the output performance of the engine. Particularly, the bearing oil supply structure of the crankshaft that is suitable when the bearing is a rolling bearing. Can provide.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram schematically showing an engine 50A including a crankshaft bearing oil supply structure (hereinafter simply referred to as a bearing oil supply structure) 10A according to the present embodiment. 1A is a cross-sectional view of the engine 50A viewed along the direction in which the crank axis extends, and FIG. 1B is a cross-sectional view of the engine 50A viewed along the direction orthogonal to the crank axis. It is. FIG. 1A is a cross section of a portion corresponding to the bearing 71 located on the leftmost side in FIG. The engine 50A includes a cylinder block 51, a cylinder head 52, a crankcase 53, and an oil pan 54, and further includes a bearing cap 55, a crankshaft 56, intake and exhaust valves 57 and 58, and cams as main components. 59, piston 60, connecting rod 61, bearing 7 (71, 72 and 73) and the like. The engine 50A is an inline 4-cylinder engine. However, the engine to which the present invention is applicable is not limited to this.

  The crankshaft 56 is configured to convert the reciprocating motion of the piston 60 into a rotational motion. The crankshaft 56 is connected to the piston 60 via connecting rods 61 at four locations. The crankshaft 56 has five journal parts. In this embodiment, the journal 7 realized by a rolling bearing is applied to the three journal parts 56a among these journal parts. However, the present invention is not limited to this, and for example, a rolling bearing may be applied to support the crankshaft 56 for all journal portions. Specifically, in the present embodiment, among the bearings 7, the leftmost bearing 71 in FIG. 1B is realized by a ball bearing, and the bearings 72 and 73 are realized by a pair of half needle bearings. . However, the present invention is not limited to this, and a part of the bearing 7 may be realized by another bearing (for example, a sliding bearing) instead of the rolling bearing. A bearing cap (corresponding to a bearing holding member described in claims) 55 is configured to hold the bearing 7 from below, and is fixed to the lower end of the cylinder block 51 by a bolt with the bearing 7 interposed therebetween. In this state, the crankshaft 56 is supported by the bearing 7. The engine 50A is provided with an oil pump (not shown) that is driven by rotation of the crankshaft 56.

  A blow-by gas passage 3 is formed in the cylinder block 51 and the cylinder head 52. The blow-by gas passage 3 is configured to guide the blow-by gas to an intake system (not shown) of the engine 50A, and a space K formed in the cylinder head 52 for arranging a valve mechanism including a cam 59, and the like. Each communicates with a space formed below the piston 60. An oil return passage 2A is formed in the cylinder block 51 and the cylinder head 52. The oil return passage 2A communicates with the space K, and the oil supplied into the space K to lubricate the sliding portion of the valve operating mechanism flows into the oil return passage 2A due to its own weight fall.

  In addition to the oil return passage 2A, the engine 50A also includes a general oil return passage 2E communicating from the space K into the oil pan 54 so that the oil can be sufficiently discharged from the space K. Further, in FIG. 1B, the portion where the oil return passage 2A or 2E overlaps with the crankshaft 56 or the bearing 7 is shown overlapped for the sake of convenience in illustrating the oil return passage 2A or 2E.

  Three oil return passages 2 </ b> A are provided corresponding to the journal portions 56 a of the crankshaft 56, in other words, the bearings 7 of the crankshaft 56. Unlike the general oil return passage 2E, the oil return passage 2A is closed below without communicating with the oil pan 54. When closing the oil return passage 2A downward, for example, the oil return passage 2A is formed so as to open to the lower surface of the cylinder block 51, and the opened oil return passage 2A is closed by the upper surface of the crankcase 53. It can be realized and processing is easy in this way. However, the present invention is not limited to this. For example, by forming the oil return passage 2 so as not to penetrate the lower surface of the cylinder block 51, the oil return passage 2 is closed downward, or the opening on the lower surface of the cylinder block 51 is closed with a plug. The oil return passage 2 may be closed at the bottom.

  The oil return passage 2A is formed so that the oil supply passage 1A is branched. The oil supply passage 1A is configured to supply oil from the oil return passage 1A to the bearing 7 (more specifically, the sliding portion of the bearing 7). In this embodiment, the oil supply passage 1 </ b> A is formed in the cylinder block 51, and opens to the bearing holding portion 51 a of the cylinder block 51 on the bearing 7 side. A through-hole (not shown) constituting a part of the oil supply passage 1A is formed in the outer race of the ball bearing (bearing 71) so as to correspond to the opening of the oil supply passage 1A. For this reason, the oil flowing into the oil return passage 2A can reach the bearing 7 through the oil supply passage 1A.

  Further, since the oil supply passage 1A is branched from the middle of the oil return passage 2A, in this embodiment, a portion of the oil return passage 2A below the portion where the oil supply passage 1A is branched (communication) It functions as an oil reservoir L. Accordingly, the oil that flows into the oil return passage 2A from the space K in the cylinder head 52 mainly accumulates in the oil reservoir L, and then flows into the oil supply passage 1A so as to overflow from the oil reservoir L. Thereby, oil can be stably supplied to the bearing 7. Further, by supplying the oil accumulated in the oil reservoir L in this way, it is possible to suppress the dust contained in the oil from reaching the bearing 7.

  In the present embodiment, the bearing oil supply structure 10A is realized by an oil supply passage 1A and an oil return passage 2A. In the bearing oil supply structure 10A thus realized, a bearing to which a rolling bearing that easily reduces the hydraulic pressure is applied. The oil pump is forcibly supplied to each of the oil pumps 7 and it is not necessary to increase the capacity of the oil pump in order to maintain the hydraulic pressure, so that the output performance of the engine is not lowered. Further, in the bearing oil supply structure 10A, oil flowing into the oil return passage 2A due to free fall is supplied to each bearing 7, so that a small amount of oil can be supplied to each bearing 7. Further, since the bearing oil supply structure 10A supplies a small amount of oil, each of the bearings 7 realized by the rolling bearing can exhibit the original low friction performance.

  FIG. 2 is a diagram schematically showing an engine 50B including the bearing structure 10B according to the present embodiment. FIG. 2 shows the engine 50B in a cross section similar to that shown in FIG. As shown. The engine 50B is substantially the same as the engine 50A except that the bearing structure 10B is provided instead of the bearing structure 10A. The bearing structure 10B is substantially the same as the bearing structure 10A except that an oil return path 2B is provided instead of the oil return path 2A. 2 shows the engine 50B in a cross section similar to that shown in FIG. 1 (a), the oil supply passage 1A and the oil return passage are similarly applied to the other bearings 72 and 73 in the engine 50B. 2B is formed. In addition, the through hole described in the first embodiment also constitutes a part of the oil supply passage 1A in this embodiment.

  The oil return passage 2B includes a passage corresponding to the oil return passage 2A described in the first embodiment as a passage 2aB, and further includes a contraction portion 2bB in a portion below the portion where the oil supply passage 1A communicates. Yes. The contraction portion 2bB communicates with the oil reservoir portion L from below, and the oil return passage 2B communicates with the oil pan 54 via the contraction portion 2bB. In the present embodiment, the narrow path portion 2bB is specifically realized by a passage formed in the crankcase 53, and is matched so that oil is accumulated in the oil reservoir portion L during engine operation. Therefore, in the oil return passage 2B, the flow passage cross-sectional area of the portion formed in the crankcase 53 (constriction portion 2bB) is larger than the flow passage cross-sectional area of the portion formed in the cylinder block 51 (passage 2aB). It is getting smaller.

  In the present embodiment, the bearing oil supply structure 10B is realized by the oil supply passage 1A and the oil return passage 2B. In the bearing oil supply structure 10B realized in this way, the oil supply passage 1B (oil reservoir L ) Can be discharged into the oil pan 54, so that dust and the like contained in the oil can be discharged into the oil pan 54 at the same time. As described above, the bearing oil supply structure 10B can further discharge the oil accumulated in the oil return passage 2B when the engine is stopped to the oil pan 54 as compared with the bearing oil supply structure 10A. Reaching the bearing 7 can be suitably suppressed.

  FIG. 3 is a view schematically showing an engine 50C including the bearing oil supply structure 10C according to the present embodiment. FIG. 3 shows the engine 50C in a cross section similar to the cross section shown in FIG. It is shown enlarged. The engine 50C is substantially the same as the engine 50A except that the bearing oil supply structure 10C is provided instead of the bearing oil supply structure 10A. The bearing oil supply structure 10C is substantially the same as the bearing oil supply structure 10A except that it includes an oil return passage 2C instead of the oil return passage 2A and an oil supply passage 1C instead of the oil supply passage 1A. It is the same thing. 3 shows the engine 50C in a cross section similar to the cross section shown in FIG. 1 (a). In the engine 50C, the oil supply passage 1C and the oil return are similarly applied to the other bearings 72 and 73. A passage 2C is formed.

  The oil return passage 2 </ b> C is formed so as to extend from the space K in the cylinder head 52 toward the side of the bearing 7 in the bearing cap 55. For this reason, the oil return passage 2C includes a portion 2cC formed in the cylinder block 51 and the cylinder head 52 and a portion 2dC formed in the bearing cap 55, and the portion 2cC formed in the cylinder block 51 and the cylinder head 52. Is open on the lower surface of the cylinder block 51. On the other hand, the portion 2dC formed in the bearing cap 55 has one end opened to the upper surface of the bearing cap 55 corresponding to the opening of the portion 2cC, and the other end closed without being communicated with the oil pan 54. Is formed.

  The oil supply passage 1C is formed to branch from a portion 2dC formed in the bearing cap 55 in the oil return passage 2C. An oil reservoir portion L is formed in a portion of the oil return passage 2C below the portion where the oil supply passage 1C branches (communicates). The oil supply passage 1 </ b> C extends so as to branch obliquely upward from the oil supply passage 2 </ b> C, and opens to the bearing holding portion 55 a of the bearing cap 55. The oil supply passage 1 </ b> C thus opened communicates with the portion of the bearing 7 before the maximum load point in the rotation direction of the crankshaft 56 via the bearing cap 55.

  For this reason, the oil that has flowed into the oil return passage 2C accumulates in the oil reservoir L, and enters the oil supply passage 1C and reaches the bearing 7 as the oil level rises. If the oil supply passage 1C is formed in this way, it is preferable in that it is possible to suppress dust and the like contained in the oil from reaching the bearing. The oil supply passage 1C is not limited to extending from the oil return passage 2C so as to branch obliquely upward and communicating with the portion before the maximum load point. For example, the oil supply passage 1C extends substantially horizontally from the oil return passage 2C. You may extend | stretch so that it may branch toward, and you may connect with the part in front of a maximum load point.

  In this embodiment, the bearing oil supply structure 10C is realized by an oil supply passage 1C and an oil return passage 2C. In the bearing oil supply structure 10C realized in this way, the oil supply passage 1C includes Since the shaft 56 communicates with the portion before the maximum load point in the rotation direction, the bearing can be effectively lubricated with a small amount of oil. In the present embodiment, the bearing cap 55 functions as a part of the sliding portion of the bearing 7 (more specifically, the bearings 72 and 73 here). Processing can be facilitated in that it is not necessary. In this way, the bearing structure 10C can effectively lubricate the bearing with a smaller amount of oil than the bearing structure 10A, and the bearing cap 55 functions as a part of the sliding portion of the bearing 7. Can further facilitate the processing.

  FIG. 4 is a view schematically showing an engine 50D provided with a bearing oil supply structure 10D according to the present embodiment. In FIG. 4, the engine 50D when a cross section similar to the cross section shown in FIG. 1A is viewed from the opposite side. The main part is enlarged and shown. The engine 50D is substantially the same as the engine 50A except that the bearing oil supply structure 10D is provided instead of the bearing oil supply structure 10A. The bearing oil supply structure 10D has a structure in which oil is forcibly supplied to the bearing 7 from the main gallery 4 instead of adopting a structure for supplying oil to the bearing 7 from the general oil return passage 2E. It is different from the bearing oil supply structure 10A. Further, the bearing oil supply structure 10D is different from the bearing oil supply structure 10A in that the bearings 72 and 73 are realized by sliding bearings instead of rolling bearings.

  The cylinder block 51 is formed with a main gallery 4 through which oil pumped by the oil pump flows. A forced oil supply passage 5 branches from the main gallery 4 and extends toward the bearing 7, and the forced oil supply passage 5 opens in a bearing holding portion 51 a of the cylinder block 51. The forced oil supply passage 5 is provided with an oil amount adjusting jet (corresponding to a throttle according to the claims) 6. An internal thread is formed on the outer periphery of the oil amount adjusting jet 6. Specifically, the oil amount adjusting jet 6 is directed inward from a portion of the forced oil supply passage 5 that is open to the bearing holding portion 51 a of the cylinder block 51. The forced oil supply passage 5 is provided by tightening the male screw formed in this manner.

  The oil amount adjusting jet 6 is configured to restrict the oil amount by a built-in orifice, and the oil supplied from the main gallery 4 is supplied to the bearing after being reduced to a small amount of oil by the oil amount adjusting jet 6. . In FIG. 4, the engine 50D is illustrated in a cross section similar to the cross section illustrated in FIG. 1A. However, in the engine 50D, the other bearings 72 and 73 are sliding bearings. No oil amount adjusting jet 6 is provided in the forced oil supply passage 5 corresponding to 73.

  In this embodiment, the bearing oil supply structure 10D is realized by the forced oil supply passage 5 provided with the oil amount adjusting jet 6. In the bearing oil supply structure 10D thus realized, a small amount of oil is supplied to the bearing 71. In addition, it is possible to suppress a decrease in hydraulic pressure that occurs when the bearing is a rolling bearing. For this reason, in the bearing oil supply structure 10D, since a small amount of oil can be supplied to the bearing 71 without particularly increasing the capacity of the oil pump, the rolling bearing 71 that supports the crankshaft 56 is supported without reducing the output performance of the engine. A small amount of oil can be supplied. Further, in the engine 50D, the rolling bearing 71 and the sliding bearings 72 and 73 coexist on the bearing 7 that supports the crankshaft 56. According to the bearing oil supply structure 10D, it is possible to supply oil suitable for each bearing 7. At the same time, it is possible to eliminate the need to provide the oil supply passage 1 exclusively for the rolling bearing 71.

  The embodiment described above is a preferred embodiment of the present invention. However, the present invention is not limited to this, and various modifications can be made without departing from the scope of the present invention. For example, in the bearing oil supply structures 100A to 100C described in the first to third embodiments, when a bearing other than the rolling bearing is applied to the bearing that supports the crankshaft 56, the bearing other than the rolling bearing is used. May be applied. At this time, oil may be forcibly supplied by an oil pump to bearings other than the rolling bearing. In this respect, if the oil is forcibly supplied to the bearings other than the rolling bearing by the oil pump, and the oil that freely falls to the oil return passage 2 is further supplied by the oil supply passage 1, the driving work of the oil pump is correspondingly increased. Can be reduced.

It is a figure showing typically engine 50A provided with bearing oil supply structure 10A. It is a figure showing engine 50B provided with bearing oil supply structure 10B typically. It is a figure showing typically engine 50C provided with bearing oil supply structure 10C. It is a figure showing typically engine 50D provided with bearing oil supply structure 10D.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Oil supply path 2 Oil return path 3 Blow-by gas path 4 Main gallery 5 Forced oil supply path 6 Oil quantity adjustment jet 7 Bearing 10 Bearing oil supply structure 50 Engine 51 Cylinder block 53 Crankcase 55 Bearing cap 56 Crankshaft

Claims (4)

An engine bearing oil supply structure for supplying oil to a bearing that supports a crankshaft,
An oil inflow portion formed from the cylinder head of the engine toward the bearing direction, into which oil supplied to the cylinder head flows;
An oil supply passage branched from the oil inflow portion and supplying oil to the bearing;
Of the oil inflow portion, an oil reservoir portion formed in a portion below the portion where the oil supply passage branches;
An engine bearing lubrication structure characterized by comprising: A bearing oil supply structure for an engine according to claim 1,
A bearing oil supply structure for an engine, characterized in that an oil pan portion of the engine communicates with the oil reservoir portion, and a constricted portion having a flow passage cross-sectional area smaller than a flow passage cross-sectional area of the oil inflow portion is provided . A bearing oil supply structure for an engine according to claim 1 or 2,
The bearing oil supply for an engine is characterized in that the oil supply passage is communicated with a portion of the bearing in front of the maximum load point in the rotation direction of the crankshaft through a bearing holding member for holding the bearing from below. Construction. An engine bearing oil supply structure according to any one of claims 1 to 3,
A bearing oil supply structure for an engine, wherein the bearing is a rolling bearing.

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