DE102012222353B4 - Oil supply structure of a crankshaft in an engine - Google Patents

Abstract

Oil supply structure of a crankshaft in an engine, which comprises a crankshaft (CS), which comprises a plurality of shaft journals (J1, J2) and a plurality of crankpins (6), and an engine body (EB), which has a plurality of bearing surfaces (B1, B1, B2) for supporting the shaft journals (J1, J2) of the crankshaft (CS), and in which: a plurality of body oil supply passages (P1, P2) for individually supplying oil to the plurality of journals (J1, J2) in the engine body (FIG. EB) is formed; an oil supply source (OP) is shared by the body oil supply passages (P1, P2) and connected to them in a parallel configuration; a cylindrical sliding bearing (M) is disposed and fixed on each bearing surface (B1, B2), an outer circumferential surface of the respective shaft journals (J1, J2) being rotatably supported by and supported by the cylindrical sliding bearing (M); a plurality of communication holes (H1 to H3) are formed in each of the sliding bearings (M) and arranged in a circumferential direction, the communication holes (H1 to H3) being connected to the corresponding body oil supply passage (P1, P2) and the sliding bearing (M) in penetrate a radial direction; the plurality of shaft journals (J1, J2) are divided into either a first shaft journal (J1) which communicates with an in-shaft oil passage (A) formed in the crankshaft (CS) for supplying oil to the crankpin (6), or a second shaft journal (J2) which does not communicate with the in-shaft oil passage (A); and of the plurality of body oil supply passages (P1, P2), a second body oil supply passage (P2) for supplying oil to the second shaft journal (J2) is provided with an oil supply amount regulating means (21) to make an amount of oil supply thereto smaller than that to a first body oil supply passage (P1) for supplying oil to the first shaft journal (J1), characterized in that ...

Description

[TECHNICAL FIELD]

The present invention relates to an oil supply structure of a crankshaft in an engine, and more particularly relates to an oil supply structure which includes a crankshaft comprising a plurality of shaft journals and a plurality of crankpins and an engine body having a plurality of bearing surfaces for supporting the crankshaft journals and wherein: a plurality of body oil supply passages for individually supplying oil to the plurality of shaft journals are formed in the engine body; an oil supply source is shared by the body oil supply passages and connected to them in a parallel configuration; a cylindrical bearing metal is fitted in and fixed to each bearing surface, an outer peripheral surface of the respective shaft journals being rotatably mounted on and supported by the cylindrical sliding bearing; and a plurality of communication holes are formed in each of the bearing metals and arranged in a circumferential direction, the communication holes being connected to the corresponding body oil supply passage and penetrating the bearing metal in a radial direction.

[BACKGROUND]

As the oil supply structure of a crankshaft described above, a structure is known in which: a plurality of shaft journals are divided into either a first shaft journal which communicates with an in-shaft oil passage through which a part of oil supplied from a body oil supply passage is supplied to crankpins; or a second shaft journal which does not communicate with the in-shaft oil passage; and of the plurality of body oil supply passages, each second body oil supply passage for supplying the oil to the corresponding second journals is provided with oil supply amount regulating means for making the amount of oil supply thereto smaller than that at each of the first body oil supply passages for supplying the oil to the first journals (see the patent document 1 below).

[STATE OF THE ART]

[Patent Document]

• [Patent Document 1] Japanese Patent Application Laid-Open JP 2008196396 A , respectively. US 20080190699 A1 ,

[SUMMARY OF THE INVENTION]

[PROBLEMS TO BE SOLVED BY THE INVENTION]

In the above-mentioned conventional structure described in Patent Document 1, the amount of oil supply to each second journal which does not require oil supply to a crankpin is limited to be smaller than the amount of oil supply to each first journal which supply oil to the crankpins required, using the oil supply amount regulating means, which is specially provided on the second body oil supply passage corresponding to the second shaft journal. Consequently, the oil is efficiently supplied to the shaft journals according to the required amounts of oil supply to the shaft journals. In this way, it is possible to reduce the size and volume of an oil supply source and to reduce losses in engine performance.

However, in this conventional structure, the provision of the above-described oil supply amount regulating means includes separately mounting an exclusive component having an opening function to an intermediate portion of each second body oil supply passage in the engine body, or extra, a bearing metal having a restricting function by reducing the diameters the communication holes and the like is achieved to use as an exclusive bearing metal for every other shaft journal. For this reason, there is the circumstance such as an increase in the number of components, which leads to an increase in cost, or the need to use for assembling different bearing metals for the plurality of shaft journals according to the required amounts of oil supply, whereby the assembly work is difficult.

The present invention has been made in view of the above, and an object thereof is to provide an oil supply structure of a crankshaft in an engine capable of solving the above conventional problems with a simple structure.

[MEANS OF SOLVING THE PROBLEM]

In order to achieve the object according to an invention of claim 1, there is provided an oil supply structure of a crankshaft in an engine comprising a crankshaft comprising a plurality of shaft journals and a plurality of crankpins and a motor body having a plurality of support surfaces for supporting the crankshaft journal comprises, and wherein: a plurality of body oil supply passages for individually supplying oil to the plurality of shaft journals are formed in the engine body; an oil supply source is shared by the body oil supply passages and connected to them in a parallel configuration; a cylindrical sliding bearing is disposed and fixed on each of the bearing surfaces, an outer peripheral surface of the respective shaft journals being rotatably mounted on and supported by the cylindrical sliding bearing; a plurality of communication holes are formed in each of the sliding bearings and arranged in a circumferential direction, the communication holes being connected to the corresponding body oil supply passage and penetrating the sliding bearing in a radial direction; the plurality of shaft journals are classified into either a first shaft journal which communicates with an in-shaft oil passage formed in the crankshaft for supplying oil to the crankpin, or a second shaft journal which does not communicate with the in-shaft oil passage; and from the plurality of body oil supply passages, a second body oil supply passage for supplying oil to the second shaft journal is provided with an oil supply amount regulating means for making an amount of oil supply thereto smaller than that to a first body oil supply passage for supplying oil to the first shaft journal characterized in that the first body oil supply passage has a communication groove recessed in the bearing surface for supporting the first shaft journal and extending in a circumferential direction of the bearing surface to communicate with the plurality of communication holes, and the second body oil supply passage has a regulating oil passage which opens on the bearing surface for supporting the second shaft journal, and communicates with only a part of the communication holes of the plurality of communication holes ized, and the regulating oil passage is set as the oil supply amount regulating means.

Further, according to an invention of claim 2, in addition to the feature of the invention of claim 1, inner diameters of at least two communication holes of the plurality of communication holes are set different from each other.

Further, according to an invention of claim 3, in addition to the feature of the invention of claim 1 or 2, the part of the communication holes in each of the sliding bearings is formed on a half circumferential portion thereof on a rear side in a rotational direction of the crankshaft, viewed from a point which is the largest load from the corresponding shaft journal experiences in an explosion cycle of the engine.

[EFFECTS OF THE INVENTION]

According to the present invention, the first body oil supply passage, which corresponds to the first shaft journal requiring a larger amount of oil supply due to the necessity of oil supply to the crank pins, has a communication groove which is provided in a recessed manner in the bearing surface for supporting the first shaft journal and which extends in the circumferential direction of the bearing surface to communicate with the plurality of communication holes. On the other hand, the second body oil supply passage, which corresponds to the second shaft journal requiring a smaller amount of oil supply due to the non-necessity of oil supply to a crankpin, has the regulating oil passage opening on the bearing surface for supporting the second shaft journal, and which only communicates a part of the communication holes of the plurality of communication holes. The regulating oil passage is set as the oil supply amount regulating means. Consequently, the provision of the oil supply amount regulating means no longer needs to separately attach an exclusive component having an opening function to the second body oil supply passage, or to use different sliding bearings for the first and second journals, as in the case of the conventional structure. Accordingly, it is possible to appropriately control the amounts of oil supply to the first and second journals, thereby reducing the number of components, thereby reducing costs and avoiding complications in assembling work.

Furthermore, particularly according to the invention of claim 2, the inner diameters of the at least two communication holes of the plurality of communication holes are set different from each other. By changing the shape or opening position of the regulating oil passage in accordance with the required amounts of oil supply to the shaft journals, it is possible to change the combination of the communication holes to communicate with the regulating oil passage. Accordingly, the amount of oil supply to be regulated by the oil supply amount regulating means (regulating oil passage) can be adjusted easily and with many variations.

Furthermore, in particular according to the invention of claim 3, the part of the communication holes in the slide bearing at the half-circumference section mentioned in claim 1 is at the Rear side arranged in the direction of rotation of the crankshaft, seen from a point which receives the largest load from the shaft journal in the explosion cycle of the engine. In the case of the second shaft journal, therefore, a half-circumferential portion of the second shaft journal at a rear side in the rotational direction thereof, as viewed from a point experiencing the magnitude load, can be efficiently supplied with oil through the part of the communication holes just before the large load is generated. Accordingly, it is possible to secure an amount of the lubricating oil which is sufficient for the second shaft journal, although oil is supplied to the second shaft journal only from the part of the communication holes through the regulation oil passage. Thereby, it is possible to prevent deterioration of the life of a sliding portion of the sliding bearing and the like.

[BRIEF DESCRIPTION OF THE DRAWINGS]

[ 1 It is a longitudinal sectional view of an essential part of a motor according to an embodiment of the present invention.

[ 2 ] It is an enlarged cross-sectional view (one along the line 2-2 in FIG 1 taken enlarged sectional view) of a first shaft journal and portions surrounding it.

[ 3 ] She is one in line 3-3 in 2 taken sectional view.

[ 4 ] It is an enlarged cross-sectional view (one along the 4-4 in 1 taken enlarged sectional view) of a second shaft journal and portions surrounding it.

[ 5 It is a series of explanatory views showing the flow of oil supplied from a second body oil supply passage to the side of the second shaft journal, with an exaggerated gap for sliding between a bearing metal and the second shaft journal, and (A) and (B) show a state immediately before an explosion stroke or a state during the explosion stroke.

EMBODIMENT OF THE INVENTION

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings 1 to 5 described.

An engine body EB of a multi-cylinder engine E intended to be mounted on a vehicle includes: a cylinder block 1 comprising a plurality of cylinders (four in the illustrated example) 1a which are arranged in a line; a cylinder head (not shown) connected to an upper portion of the cylinder block 1 connected is; a lower block 2 and an oil pan 3 , which successively with a lower portion of the cylinder block 1 are connected. The lower section of the cylinder block 1 and the lower block 2 and the oil pan 3 define a crankcase 4 ,

In the crankcase 4 a crankshaft CS is received, which extends in the direction in which the cylinders 1a are arranged and which is rotatably arranged and supported on a plurality of bearing surfaces B1, B2 of the engine body EB. Further, an oil pump OP serving as an oil supply source configured to be driven by the crankshaft CS is disposed in the oil pan 3 pump up stored lubricating oil.

The crankshaft CS includes: a plurality of shaft journals J1, J2 arranged at intervals therebetween in an axial direction of the crankshaft CS and rotatably disposed and supported on the plurality of bearing surfaces B1 and B2, respectively, of the engine body EB; crank webs 5 which extend integrally radially outwardly from the pairs of adjacent journals J1, J2; and crankpins 6 , which the respective crank webs 5 connect integrally. With each crankpin 6 is a big connecting rod eye of a connecting rod 10 , which with a displaceable in the corresponding cylinder 1a arranged piston 7 is connected, rotatably coupled.

In a lower section of the cylinder block 1 are storage walls 1b formed integrally, in the lower surfaces of the upper halves of the bearing surfaces B1 and B2 are formed. bearing cap 8th in whose upper surfaces the lower halves of the bearing surfaces B1, B2 are formed, are detachable on the respective lower surfaces of the bearing walls 1b fastened, with screws are not shown.

In the engine body EB (ie the bearing walls 1b of the cylinder block 1 ), a plurality of body oil supply passages P1, P2 are formed, through which the oil is to be supplied individually to the plurality of journals J1, J2. Downstream sides of the body oil supply passages P1 and P2 open at the upper halves of their respective bearing surfaces B1 and B2, respectively. Further, upstream sides of the body oil supply passages P1, P2 are in series with a drain side of the oil pump OP through one through a wall of the cylinder block 1 along the axis of the crankshaft CS extending oil distribution 9 connected.

A cylindrical bearing metal M is arranged and fixed as a sliding bearing on each bearing surface B1, B2. An outer peripheral surface of the corresponding journal J1, J2 of the bearing surface B1, B2 is rotatably disposed on the bearing metal M and supported. The bearing metal M is formed of separate bodies, namely a semi-cylindrical upper metal half Mu, which at the upper half of the in the corresponding bearing wall 1b of the cylinder block 1 formed bearing surface B1, B2, and a semi-cylindrical lower metal half MI, which at the lower half of the in the corresponding bearing cap 8th formed bearing surface B1, B2 is arranged in close contact. Furthermore, in a state in which the bearing walls 1b of the cylinder block 1 and the bearing caps 8th are fixed to each other, with the shaft journals J1, J2 and the upper and lower metal halves Mu, MI therebetween, the upper and lower metal halves Mu, MI are fixed to the upper and lower halves of the bearing surfaces B1 and B2, respectively, in such a manner that opposite Ends of the upper and lower metal halves Mu, MI facing each other are in contact with each other.

In each bearing metal, in particular in each upper metal half Mu, are formed: a recessed groove g which extends in an inner circumferential surface thereof over the entire length in a circumferential direction; and a plurality of first to third communication holes H1 to H3 juxtaposed at intervals therebetween in the circumferential direction at positions coincident with the recessed groove g and also penetrating the upper metal half Mu in a radial direction. As will be described later, the body oil supply passage P1, P2 communicates with all or part of the communication holes H1 to H3.

Furthermore, at least two of the communication holes H1 to H3 are formed with different diameters. Specifically, in the illustrated example, the first and second communication holes H <b> 1, H <b> 2 are formed with the same diameter, while the third communication hole H <b> 3 is formed smaller in diameter than the first and second communication holes H <b> 1, H <b> 2, so that it is possible to form a limiting one To exert effect on the flow of the discharged oil.

Further, the third communication hole H3 in each bearing metal M (upper metal half Mu) is disposed at a half circumferential portion at a rear side in the rotational direction of the crankshaft CS, as viewed from a point X (see FIG. 5 (B) ), which receives the largest load from the journal J1, J2 in an explosion stroke of the motor E, whereas the first communication hole H1 is disposed at a half-circumferential portion at a front side in the rotational direction. Further, the second communication hole H2 is disposed on the opposite side of the crankshaft axis from the point X experiencing the largest load.

The structure of the bearing metal M described above is the same for all the bearing metals which are attached to the crankshaft CS supporting bearing surfaces B1, B2. For this reason, it is no longer necessary to use various bearing metals for the journals J1, J2, thereby making it possible to correspondingly reduce the number of components and eliminate the possibility of erroneous mounting.

Meanwhile, all journals J1, J2 included in the crankshaft CS are divided into either: a first shaft J1 communicating with an in-shaft oil passage A formed inside the crankshaft CS such that a part of the lubricating oil supplied to the shaft journal continue to the corresponding crank pin 6 can be supplied; or a second journal J2, which does not communicate with the in-shaft oil passage A. Specifically, in the illustrated example, the three shaft journals located at opposite ends and in the middle in the axial direction of the crankshaft CS correspond to the second journall J2, whereas the other journals (ie, the two journals located between the adjacent second journals J2) correspond to the first shaft journal J1.

In the illustrated example, each in-shaft oil passage A is formed of: a transverse oil passage 11 extending transversely across the first shaft J1 and having opposite ends opening on an outer peripheral surface of the first shaft J1; and a pair of longitudinal oil passages 12 each having an end directly connected to the transverse oil passage 11 communicates, and wherein the other end on an outer peripheral surface of the crank pin 6 opens on one or the other side in the axial direction of the first shaft journal J1. guide 13 , which engage the openings at opposite ends of the transverse oil passage 11 are provided in a recessed manner in the outer peripheral surface of the respective first shaft journal J1.

Each longitudinal oil passage 12 is formed of: a first oil passage 12a , which is straight through the first shaft journal J1, the crank arm 5 , and the crankpin 6 is drilled using a drill or the like; and a second oil passage 12b extending from an intermediate portion of the first oil passage 12a branches and sticks to the outer peripheral surface of the crankpin 6 opens. One end of the first oil passage 12a , which is to the crank arm 5 opens with a closing body 18 closed, which is then attached to it.

All body oil supply passages P1, P2 contained in the engine body EB are classified into either: a first body oil supply passage P1 for supplying the oil to the first shaft journal J1 (and, accordingly, the crankpins 6 through the first shaft journal J1); or a second body oil supply passage P2 for supplying the oil to the second shaft J2. Thus, every second body oil supply passage P2 only needs to allow an oil supply large enough to lubricate its corresponding second shaft journal J2; therefore, a part of the lubricating oil, which is supplied to the second journal J2, does not need the side of the crankpin 6 be supplied. Consequently, the required amount of oil supply to the second body oil supply passage P2 may be relatively small compared to that to the first body oil supply passage P1. Therefore, in this embodiment, as will be described later, the second body oil supply passage P2 is provided with an oil supply amount regulating means 21 to make the oil supply amount smaller than that to the first body oil supply passage P1, so that the oil supplies are balanced to the first and second body oil supply passages P1, P2 which differ in the required oil supply amount.

Furthermore, the first body oil supply passage P1 has a communication groove at its downstream end 20 which is provided in a recessed manner in the first bearing surface B1 corresponding to the first shaft J1, and which extends in the circumferential direction of the first bearing surface B1 to communicate with all of the first to third communication holes H1 to H3 in the bearing metal M.

On the other hand, the second body oil supply passage P2 has a regulating oil passage at its downstream end 21 which opens at the second bearing surface B2 corresponding to the second shaft journal J2 and communicates with only a part of the communication holes in the bearing metal M (the third communication hole H3 in the illustrated example). The regulatory oil passage 21 is formed as the above oil supply amount regulating means. In the illustrated example, the regulating oil passage is 21 is formed as a spherical surface having a larger diameter than an inner diameter of the second body oil supply passage P2, thereby expanding the area of the second body oil supply passage P2 opening toward the second support surface B2. This widened opening area points only to the third communication hole H3 from the first to third communication holes H1 to H3.

Hereinafter, operations of the above embodiment will be described.

In a state where the engine E is in operation, the oil pump OP driven by the crankshaft CS pumps the lubricating oil in the oil pan 3 high to continuously supply the oil to each section to be lubricated in the engine. Then it's about the oil distribution 9 in the wall of the cylinder block 1 a part of the oil discharged from the oil pump OP and also supplied to the first and second body oil supply passage P1, P2. From there, the part of the oil is supplied to the first and second journals J1, J2 through the bearing metals M at the respective first and second bearing surfaces B1, B2 of the engine block EB.

As in 2 In this case, the lubricating oil flowing through the first body oil supply passage P1 reaches the outer peripheral surface of the first shaft journal J1, passing through the communication groove 20 which is disposed at the downstream end of the first body oil supply passage P1 and opens at the first bearing surface B1, and then flows through the first to third communication holes H1 to H3 and the recessed groove g in the bearing metal M. Consequently, the lubricating oil lubricates a gap for sliding between the outer peripheral surface of the first shaft journal J1 and an inner circumferential surface of the bearing metal M. Further, flows through the guide grooves 13 , which open on the outer peripheral surface of the first shaft journal J1, a part of the lubricating oil in the transverse oil passage 11 of the in-shaft oil passage A. From there, the part of the lubricating oil flows through each longitudinal oil passage 12 of the in-shaft oil passage A and reaches the outer peripheral surface of the corresponding crankpin 6 , Due to this, the part of the lubricating oil lubricates a sliding portion between the outer peripheral surface of the crankpin 6 and a bearing surface of the large connecting rod eye of the corresponding connecting rod 10 ,

As in 4 On the other hand, the lubricating oil flowing through the second body oil supply passage P2 reaches the outer peripheral surface of the second shaft journal J2, passing through the regulating oil passage 21 which is located at the downstream end of the second body oil supply passage P2 and opens at the second bearing surface B2, and then flows through the third communication hole H3 and the recessed groove g in the bearing metal M. Consequently, the lubricating oil lubricates a gap for sliding between the outer peripheral surface of the second shaft journal J2 and the inner circumferential surface of the bearing metal M. The downstream side of the second body oil supply passage P2 is here only with the relatively small diameter third communication hole H3 in the bearing metal M via the regulating oil passage 21 in communication. By this communication portion, the amount of oil supply to the second shaft J2 is limited and kept sufficiently smaller than the amount of oil supply to the side of the first shaft J1 of the first body oil supply passage P1, which does not undergo such a limiting effect.

As described, the first body oil supply passage P1 corresponding to the first shaft journal J1 has a larger oil supply amount due to the necessity of supplying oil to the crankpins 6 needed, the long communication groove 20 which is provided in a recessed manner in the first bearing surface B1 for supporting the first shaft journal J1 and which extends in the circumferential direction of the bearing surface B1 to communicate with all of the plurality of communication holes H1 to H3 in the bearing metal M. On the other hand, the second body oil supply passage P2, which corresponds to the second shaft journal J1, has a smaller oil supply amount due to the absence of oil supply to a crankpin 6 needed, the regulatory oil passage 21 which opens on the second bearing surface B2 for supporting the second shaft journal J2 and which communicates with only a part of the plurality of communication holes H1 to H3 (ie, the third communication hole H3). The regulatory oil passage 21 is set as the oil supply amount regulating means. Therefore, the lubricating oil can be efficiently and appropriately distributed to the journals J1, J2 in accordance with the required amounts of oil supply to the first and second journals J1, J2. Accordingly, it is possible to reduce the size and volume of the oil pump OP serving as the oil supply source, and also to reduce losses in engine performance.

Besides, in order to provide the oil supply amount regulating means, no special attachment of an exclusive component having a passage function to the second body oil supply passage P2 or use of exclusive bearing metals for the first and second journals J1, J2 is required, as is the case for the conventional structure is. Accordingly, it is possible to appropriately control the amounts of oil supply to the first and second journals J1, J2 while reducing the number of components, thereby reducing the cost, and also avoiding complication in assembly work. Furthermore, the possibility of incorrect mounting of the bearing metal M is eliminated, since the same bearing metal M can be used for all journals J1, J2.

Besides, in this embodiment, the inner diameters of at least two communication holes among the plurality of communication holes H1 to H3 formed in the bearing metal M (the communication holes H1, H2 and the communication hole H3 in the illustrated example) are set to be different from each other are. By simply changing the shape or opening position of the regulating oil passage 21 According to the required amount of oil supply to the journals J1, J2, it is possible the combination of the communication holes, with the Regulierungsöldurchgang 21 communicate in a variety of ways. Accordingly, the oil supply amount regulating means (regulating oil passage 21 ) to be adjusted to be regulated oil supply amount in a simple manner and with more variations than otherwise.

Further, in this embodiment, the third communication hole H3 is disposed in the bearing metal M at the half-circumferential portion at the rear in the rotational direction of the crankshaft CS, as viewed from the point X, which has the largest load on the journal J1, J2 in the explosion stroke of the engine E absorbs, as it does in 5 (B) is shown. Therefore, particularly in the case of the second shaft journal J2, a half-circumferential portion of the second shaft journal J2 at a rear side in the rotational direction thereof, as viewed from the point X receiving the largest load, can efficiently communicate with the oil through the third communication hole 3 be supplied immediately before the largest load is generated (see 5 (A) ). Therefore, it is possible to secure an amount of lubricating oil sufficient for the second journal J <b> 2, although the amount of oil supply to the second journal J <b> 2 is relatively small due to the oil supply only through the third communication hole H <b> 3. Thereby, it is possible to prevent deterioration of the life of the sliding portion of the bearing metal M and the like. In addition, it can further contribute to the reduction of the size of the oil pump OP and the reduction of engine power loss that the amount of oil supply to the second journal J2 can be further reduced.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various changes in the embodiment can be made without departing from the present invention described in the claims.

For example, although the above embodiment has been shown for a case where the present invention has been applied to a straight four-cylinder engine, the present invention is applicable also to in-cylinder and multi-cylinder V engines having more or less than four cylinders. Furthermore, the engine type may be a four-stroke engine or a two-stroke engine. Further, the engine type may be a gasoline engine or a diesel engine.

Furthermore, the shape of the communication groove 20 which is disposed at the downstream end of the first body oil supply passage P1 and communicates simultaneously with the plurality of communication holes H1 to H3 in the bearing metal M, not limited to the above embodiment. That is, various variations are applicable as long as they are in the form of a groove which simultaneously communicates with the plurality of communication holes H1 to H3 and opens on the first bearing surface B1.

Moreover, the shape of the regulatory oil passage 21 , which is located at the downstream end of the second body oil supply passage P2 and communicates with only a part of the plurality of communication holes H1 to H3 in the bearing metal M, that is, the communication hole H3, not limited to the above embodiment. Various variations are applicable as long as they are in the form of a passage communicating with only a part of the communication holes and opening at the second bearing surface B2.

Further, the regulation oil passage may communicate with a plurality of (but a smaller number than the total number of communication holes) communication holes, depending on the required oil supply amount to the second journal J2 in the present invention, though the regulating oil passage 21 communicates with only one communication hole H3 in the above embodiment.

In order to provide an oil supply structure of a crankshaft capable of properly controlling the amounts of oil supply to first and second journals while reducing the number of components and avoiding complications of assembling work, the oil supply structure of a crankshaft is arranged to in that: a first body oil supply passage and a second body oil supply passage are formed in a motor, the first body oil supply passage corresponding to the first shaft journal requiring a larger amount of oil supply due to the need for oil supply to a crankpin, and the second body oil supply passage corresponding to the second shaft journal requires a smaller amount of oil supply due to the lack of oil supply to a crankpin; and the second body oil supply passage is provided with oil supply amount regulating means for making the amount of oil supply thereto smaller than that to the first body oil supply passage.

[MEDIUM FOR SOLUTION]

A first body oil supply passage P1 has a communication groove 20 which is provided in a recessed manner in a bearing surface B1 for supporting a first shaft journal J1 and which extends in a circumferential direction of the bearing surface to communicate with a plurality of communication holes H1 to H3 in a sliding bearing M.

A second body oil supply passage P2 has a regulating oil passage 21 which opens on a bearing surface B2 for supporting a second shaft journal J2, and which communicates with only a part of the communication holes H3 in the sliding bearing M. The regulatory oil passage 21 is as an oil supply amount regulating agent 21 set up.

LIST OF REFERENCE NUMBERS

A

In wave-oil passage

B1, B2

First and second storage areas

CS

crankshaft

e

engine

EB

Engine block as engine body

H1 to H3

First to third communication holes

J1, J2

First and second shaft journals

M

Bearing metal as plain bearing

operating room

Oil pump as oil supply source

P1, P2

First and second body oil supply passages

X

Point of the bearing surface, which experiences the largest load from the second shaft journal in the explosion cycle of the engine

6

crank pin

20

communication groove

21

Regulating oil passage as oil supply amount regulating agent

Claims (3)

Oil supply structure of a crankshaft in an engine, which has a crankshaft (CS), which has a plurality of shaft journals (J1, J2) and a plurality of crankpins ( 6 ), and an engine body (EB) comprising a plurality bearing surfaces (B1, B2) for supporting the shaft journals (J1, J2) of the crankshaft (CS), and in which: a plurality of body oil supply passages (P1, P2) for individually supplying oil to the plurality of shaft journals (J1, J2 ) is formed in the engine body (EB); an oil supply source (OP) is shared by the body oil supply passages (P1, P2) and connected to them in a parallel configuration; a cylindrical sliding bearing (M) is arranged and fixed on each bearing surface (B1, B2), an outer circumferential surface of the respective shaft journals (J1, J2) being rotatably mounted on and supported by the cylindrical sliding bearing (M); a plurality of communication holes (H1 to H3) are formed in each of the sliding bearings (M) and arranged in a circumferential direction, the communication holes (H1 to H3) being connected to the corresponding body oil supply passage (P1, P2) and the sliding bearing (M) in penetrate a radial direction; the plurality of shaft journals (J1, J2) are divided into either a first shaft journal (J1) which is provided with an in-shaft oil passage (A) formed in the crankshaft (CS) for supplying oil to the crankpin (FIG. 6 ), or a second shaft journal (J2) which does not communicate with the in-shaft oil passage (A); and of the plurality of body oil supply passages (P1, P2), a second body oil supply passage (P2) for supplying oil to the second shaft journal (J2) with an oil supply amount regulating means (P1). 21 ) to make an amount of oil supply thereto smaller than that to a first body oil supply passage (P1) for supplying oil to the first shaft journal (J1), characterized in that the first body oil supply passage (P1) has a communication groove (P1) 20 ) provided in a recessed manner in the bearing surface (B1) for supporting the first shaft journal (J1) and extending in a circumferential direction of the bearing surface (B1) to communicate with the plurality of communication holes (H1 to H3), and the second body oil supply passage (P2) has a regulating oil passage (FIG. 21 ) which opens on the bearing surface (B2) for supporting the second shaft journal (J2) and which communicates with only a part of the communication holes (H3) of the plurality of communication holes (H1 to H3), and wherein the regulating oil passage ( 21 ) as the oil supply amount regulating means ( 21 ) is set up. An oil supply structure of a crankshaft in an engine according to claim 1, wherein inner diameters of at least two communication holes (H1, H2; H3) of the plurality of communication holes (H1 to H3) are set different from each other. An oil supply structure of a crankshaft in an engine according to claim 1 or 2, wherein the part of the communication holes (H3) in each of the plain bearings (M) is formed on a half-circumferential portion thereof on a rear side in a rotational direction of the crankshaft (CS) as seen from a point (H). X) experiencing the greatest load from the corresponding journal (J1, J2) in an explosion cycle of the engine.

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