JP4397263B2 - Machine with crankshaft - Google Patents

Description

  The present invention relates to a machine including a crankshaft having a journal and a crankpin, and more particularly to a structure of an in-shaft oil passage formed in the crankshaft for supplying lubricating oil to the journal and the crankpin. The machine is, for example, an internal combustion engine.

As a technique related to the in-shaft oil passage formed in the crankshaft, for example, those disclosed in Patent Documents 1 and 2 are known. The crankshaft of the engine disclosed in Patent Document 1 is formed with an oil hole having an inlet on the side surface in the axial direction of the journal. The oil supplied from the oil pump is ejected from the oil outlet hole to the connecting rod through the oil hole. In each journal, the oil hole is formed at a position intersecting the rotation center line of the crankshaft, while the oil outlet hole of the oil hole is not formed in the journal.
JP 2002-155717 A (FIG. 1)

  Generally, a plain bearing is used as the main bearing that supports the crankshaft. On the bearing surface of the plain bearing, there is formed a groove through which lubricating oil supplied from the oil pump flows through an oil passage formed in a bearing portion (for example, a cylinder block) that supports the plain bearing. An oil film is formed between the journal and the plain bearing by the supplied lubricating oil. However, since there is a large amount of high-pressure lubricating oil in the groove as compared with the lubricating oil necessary for forming the oil film, an intermittent load from a reciprocating member (for example, a piston) acts on the groove. Due to the swing of the crankshaft, there is a problem that the amount of lubricating oil leakage from between the journal and the plain bearing increases. When the leaked lubricating oil adheres to the crankshaft, the crankshaft performs work for scattering the adhering lubricating oil, and the scattered lubricating oil rebounds at a member in the crank chamber or the crankcase. When it collides with the shaft, the colliding lubricating oil becomes resistant to the rotation of the crankshaft, causing a power loss of the crankshaft.

  In addition, the amount of lubricating oil leaking from between the journal and plain bearing is large, so it is difficult to reduce the pump capacity in order to secure the required amount of oil to the crankpin supplied through the journal. This hindered the miniaturization of the oil pump.

The present invention has been made in view of such circumstances, and the invention according to claims 1 to 6 is directed to a machine including a crankshaft, in which the power loss of the crankshaft is reduced and the lubricating oil supply device is downsized. It is another object of the present invention to ensure the supply of a required amount of lubricating oil. The invention of claim 2, wherein further, even when the shaft oil passage is elongated in the axial direction, intended to ensure the supply of the required amount of lubricating oil, according to claim 5, wherein the invention further aims to improve the stability of the lubricant in the supporting surface of the supporting surface and the crank pin of the secondary journal lubrication oil by shaft oil passage is supplied, according to claim 6, wherein Another object of the invention is to increase the reliability of the main bearing or increase the rigidity of the crank web.

According to a first aspect of the present invention, there is provided a predetermined number of bearing portions, a crankshaft having the predetermined number of journals supported by the predetermined number of the bearing portions, and one or more crankpins, and lubricating oil. Each journal is rotatably supported by a main bearing comprising a plain bearing of each bearing portion on the supported surface, and the crank pin is a reciprocating member on the support surface. In a machine in which an in-shaft oil passage is formed on the crankshaft to guide lubricating oil to the support surface.
In the predetermined number of the journals, an inlet of the oil passage in the shaft into which the lubricating oil supplied from the supply device flows is formed, and the lubricating oil supplied from the supply device is guided to the supported surface. A primary journal, and a secondary journal through which the lubricating oil flowing in from the inlet is guided to the supported surface through the in-shaft oil passage, the in-shaft oil passage includes a main passage having the inlet; and A pin passage that is connected to the first connection portion of the main passage and guides the lubricating oil of the main passage to the support surface of the crankpin, and a lubricating oil of the main passage is connected to the second connection portion of the main passage. A journal passage leading to a supported surface of the secondary journal, and the main passage is connected to the inlet and the pin passage through which lubricating oil from the inlet first flows in through the inflow portion . Lubricating oil is applied to the connecting part by centrifugal force. A first passage formed of an outward passage, and a second passage extending between the first connection portion and the second connection portion at a position away from the rotation center line of the crankshaft over the entire passage. And the entire passage of the second passage is separated from the rotation center line by a distance not less than a distance from the rotation center line to the inflow portion of the first passage .

According to this, since the lubricating oil flowing from the inlet formed in the primary journal is supplied to the supported surface of the secondary journal through the in-shaft oil passage formed in the crankshaft, the lubricating oil is applied to the bearing surface. Since it is not necessary to use the plain bearing in which the groove | channel which accumulates is formed as a main bearing, the leakage amount of the lubricating oil from between the supported surface of a secondary journal and a main bearing can be reduced.
Further, since the lubricating oil pressurized by the centrifugal force in the first passage is supplied to the supported surface of the secondary journal and the supporting surface of the crankpin, the supply hydraulic pressure in the supply device is reduced accordingly. Can do. Further, since the lubricating oil from the first passage flows through the second passage passing through a position away from the rotation center line in the whole passage, the lubricating oil flows inward in the radial direction from the viewpoint of passage formation. Even when the second passage is formed, a decrease in hydraulic pressure due to the centrifugal force in the second passage is suppressed.
Further, even when the lubricating oil in the second passage flows inward in the radial direction, the decrease in hydraulic pressure due to the centrifugal force is prevented or suppressed less than the increase due to the centrifugal force in the first passage. Even if the decrease of the hydraulic pressure in the inner oil passage is further suppressed and the air mixed in the lubricating oil stays in the middle of the oil passage in the shaft, the hydraulic pressure that overcomes the air pressure can be secured.

  According to a second aspect of the present invention, in the machine according to the first aspect, the main passage is a spiral that extends in the circumferential direction around the rotation center line as it extends in the axial direction by the first passage and the second passage. It is formed in the shape of a channel.

  According to this, even when there are a plurality of secondary journals supplied through the in-shaft oil passage and the in-shaft oil passage is formed long in the axial direction, from the primary journal to the secondary journal at the most downstream position. The lubricating oil can be supplied in a state in which a decrease in hydraulic pressure due to the centrifugal force in the second passage is suppressed. Furthermore, since it is possible to avoid the sudden bending of the passages in the first and second passages, hydraulic loss due to the passage shape is reduced.

  According to a third aspect of the present invention, in the machine according to the second aspect, the lubricating oil flows in the first passage and the second passage while being bent in a circumferential direction in a direction opposite to a rotation direction of the crankshaft. Is.

  According to this, since the lubricating oil is pushed deeper into the first and second passages by the rotation of the crankshaft, an increase in hydraulic pressure in the in-shaft oil passage is promoted.

According to a fourth aspect of the present invention, in the machine according to any one of the first to third aspects, the entrance is directed toward the rotation center line in a state of intersecting a plane perpendicular to the rotation center line. It is connected to the first passage through an introduction passage extending linearly inward in the radial direction.

  According to this, the position of the inflow portion of the first passage connected to the introduction passage can be set to a position intersecting the rotation center line or a position close to the rotation center line by the introduction passage having the shortest length. The hydraulic pressure loss in the introduction passage is reduced, and the pressurizing action by the centrifugal force on the lubricating oil in the first passage can be increased.

The invention according to claim 5 is the machine according to any one of claims 1 to 4 , wherein the predetermined number is an odd number of 5 or more, and the primary journal and the secondary journal are in the axial direction. These are arranged symmetrically with respect to the central journal located at the center.

  According to this, since the primary journal and the secondary journal are symmetrically arranged with respect to the central journal, the in-shaft oil passages have two systems, and the supported surface or crank of each secondary journal at the most downstream position. It becomes easy to supply the required amount of lubricating oil to the support surface of the pin, and it is possible to supply substantially the same amount of lubricating oil to the symmetrically arranged secondary journals.

According to a sixth aspect of the present invention, in the machine according to any one of the first to fifth aspects, the predetermined number of the journals includes one primary journal and the remaining secondary journals. The inlet is open to an annular groove formed in a circumferential direction on the supported surface of the primary journal, and all the secondary journals are not formed with a groove for storing lubricating oil on the bearing surface. The main bearing is supported by the bearing portion.

  According to this, the amount of leakage of the lubricating oil from between the supported surface of the secondary journal and the main bearing is reduced as compared with a plain bearing in which a groove on which the lubricating oil is accumulated is formed on the bearing surface. The area of the bearing surface of the main bearing can be increased, or the width of the main bearing can be reduced by the absence of the groove in which the water accumulates. In addition, since the inlet of the oil passage in the shaft opens into the annular groove of the primary journal, the lubricating oil can easily flow into the oil passage in the shaft, and lubrication from between the supported surface of the primary journal and the main bearing can be achieved. Oil leakage is also reduced.

According to invention of Claim 1, the following effect is show | played. In other words, the amount of leakage of the lubricating oil from between the supported surface of the secondary journal of the crankshaft and the main bearing can be reduced, which is caused by scattering of the leaked lubricating oil by the crankshaft and collision with the crankshaft. Therefore, the power loss of the crankshaft can be reduced, and the amount of oil supplied from the supply device can be reduced, so that the supply device is reduced in size. In addition, since the lubricating oil pressurized by the centrifugal force is supplied between the supported surface of the secondary journal and the main bearing, and between the supporting surface of the crankpin and the connecting member, The supply hydraulic pressure can be reduced, and the supply device can be downsized in this respect as well. Further, since the decrease in hydraulic pressure due to the centrifugal force in the second passage for guiding the lubricating oil in the in-shaft oil passage to the secondary journal is suppressed, it is possible to prevent the crank pin between the supported surface of the secondary journal and the main bearing. Even if the supply hydraulic pressure of the supply device is set low between the support surface and the connecting member, the required amount of lubricating oil can be reliably supplied.
In addition, the oil pressure drop due to centrifugal force is further suppressed in the oil passage in the shaft, and the oil pressure that overcomes the air pressure of the air staying in the oil passage in the shaft can be secured, so the required amount of lubricating oil can be more reliably secured. Can supply.

  According to invention of Claim 2, in addition to the effect of the invention of the cited claim, there exists the following effect. That is, even when the in-shaft oil passage extends long in the axial direction, the decrease in the oil pressure due to the centrifugal force in the second passage is suppressed, and the hydraulic loss due to the passage shape is reduced. The required amount of oil can be reliably supplied to the supported surface of the secondary journal and the supporting surface of the crank pin up to the downstream position.

  According to the invention described in claim 3, since the lubricating oil in the main passage is pushed deeper, the effect of the invention described in claim 2 is further enhanced.

According to invention of Claim 4 , in addition to the effect of the invention of the cited claim, there exists the following effect. That is, the pressure loss of the lubricating oil in the introduction passage is reduced and the pressurizing action by the centrifugal force on the lubricating oil in the first passage can be increased, so that the required amount of lubricating oil can be supplied more reliably.

According to the invention described in claim 5 , in addition to the effect of the invention described in the cited claim, the following effect is produced. That is, it becomes easy to supply the required amount of lubricating oil to the supported surface of each secondary journal or the support surface of the crank pin at the most downstream position, and is almost the same as the secondary journal arranged symmetrically. Since an equal amount of lubricating oil can be supplied, the stability of the lubrication on the supported surface of the secondary journal and the supporting surface of the crank pin to which the lubricating oil is supplied by the in-shaft oil passage is improved.

According to the sixth aspect of the present invention, in addition to a reduction in the amount of leakage of lubricating oil from between the supported surface of the secondary journal and the main bearing, there is further a difference between the supported surface of the primary journal and the main bearing. Since the amount of leakage of lubricating oil from the gap is also reduced, the same effect as that of the first aspect of the invention can be enhanced in terms of reducing the power loss of the crankshaft and reducing the size of the supply device. Also, the area of the bearing surface of the main bearing can be increased to improve the reliability of the main bearing, or the width of the main bearing can be reduced and the width of the crank web in the axial direction can be increased accordingly. Thus, the rigidity can be increased.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
A first embodiment of the present invention will be described with reference to FIGS. An internal combustion engine, which is a machine to which the present invention is applied, is a V-type 6-cylinder four-stroke internal combustion engine, and is mounted on a vehicle in a lateral arrangement in which the crankshaft 1 shown in FIG. The internal combustion engine includes a cylinder block in which first and second banks are integrally formed, each of which includes three cylinders into which pistons as reciprocating members are fitted so as to be reciprocally movable to form a V-shape. An engine main body as a machine main body including a cylinder head coupled to the upper end portion of the cylinder head and an oil pan coupled to the lower end portion of the cylinder block is provided. A crankcase composed of a lower portion of the cylinder block and the oil pan forms a crank chamber in which the crankshaft 1 is accommodated. Each of the pistons is driven to reciprocate by a combustion pressure generated by combustion of a mixture of fuel and air supplied to a combustion chamber formed between the piston and the cylinder head, The crankshaft 1 is rotationally driven via a connecting rod 11 (see FIG. 2) which is a connecting member for connecting the piston and the crankshaft 1.

2 and 3, the crankshaft 1 has a predetermined number of first to fourth journals J1 to J4 spaced apart in the axial direction, here four journals and three pairs of crank webs. W1a, W1b; W2a, W2b; W3a, W3b and three first to third crankpins P1 to P3 are integrated crankshafts integrally formed of metal. A pair of crank webs W1a, W1b; W2a, W2b; W3a, W3b respectively connected to journals J1, J2; J2, J3; J3, J4 which are adjacent in the axial direction are respectively crank arms 2a-7a and balance weights 2b-7b. And have. Each pair of crank webs W1a, W1b; W2a, W2b; W3a, W3b crank arms 2a, 3a; 4a, 5a; And a pair of first and second pin portions P1a, P1b; P2a, P2b; P3a, P3b. In each crank pin P1, P2, P3, the first pin portion P1a, P2a, P3a is a connecting rod 11 connected to the piston belonging to the cylinder of the first bank through a plane bearing 12 as a radial bearing pivot The second pin portions P1b, P2b, and P3b pivotally support a connecting rod 11 connected to a piston belonging to the cylinder of the second bank via a plain bearing 12. The journals J1 to J4 are rotatably supported by the supported bearing surfaces 13 to 16 by plain bearings 31 to 34 of the bearing portions B1 to B4, which will be described later, and the crank pins P1 to P3 are supported by the supporting surfaces. The connecting rod 11 is pivoted at 21-23.
2 and 5, the connecting rod 11 and the plain bearing 12 are shown with respect to only a part of the crankpin P1 in order to avoid complexity.

One shaft end 1a of the crankshaft 1 has an oil pump mounting portion as a lubricating oil supply device and a camshaft of a valve gear that opens and closes an intake / exhaust valve in order from the first journal J1. A drive sprocket mounting portion, which is a drive rotating body of a transmission mechanism for rotationally driving in synchronization with, and a crank pulley mounting portion of an auxiliary drive mechanism for driving an auxiliary device such as a cooling water pump or a generator are provided. . The other shaft end 1b of the crankshaft 1 is provided with a flywheel mounting portion 27 coupled to a transmission including a transmission or the like. Therefore, the oil pump is a pump that is driven by the power of the crankshaft 1 and includes, for example, a trochoid pump as a rotary pump having a rotor that slides and rotates in the pump housing.
In the specification and claims, the axial direction, the radial direction, and the circumferential direction are respectively a direction in which the rotation center line L of the crankshaft 1 extends, a radial direction about the rotation center line L, and a rotation center. It means the direction around the line L.

  The crankshaft 1 is rotatably supported by a bearing device composed of a predetermined number of four first to fourth bearing portions B1 to B4 by the first to fourth journals J1 to J4. Each bearing part B1-B4 is comprised from the plain bearings 31-34 which comprise a main bearing, and the bearing support member which supports the plain bearings 31-34. The bearing support member includes a bearing wall 36 as a first bearing support member that is a part of the cylinder block, and a bearing cap as a second bearing support member fastened to each bearing wall 36 by a bolt (not shown). 37. Each plain bearing 31 to 34 is supported by a semi-cylindrical first bearing half 31 a to 34 a supported by a bearing groove having a semicircular cross section of the bearing wall 36 and a semicircular cross section bearing groove of the bearing cap 37. It consists of semi-cylindrical second bearing halves 31b to 34b. Each of the plain bearings 31 to 34 is a grooveless plain bearing that is a bearing in which a groove for storing lubricating oil is not formed on the bearing surfaces that are inner peripheral surfaces of the bearing half bodies 31a to 34a and 31b to 34b. Further, as shown in FIG. 4, in one bearing half 31a of the plain bearing 31 that supports the first journal J1, lubricating oil from the oil passage 38 formed in the bearing wall 36 is supplied to the bearing surfaces 31a1, 31b1. An oil passage 39 is formed leading to

  1 to 4, a supply passage 40 and an in-shaft oil passage 41 are formed in the crankshaft 1. (For convenience, the in-shaft oil passage 41 is indicated by a one-dot chain line in FIG. 3.) The supply passage 40 is a main gallery which is a passage formed in the cylinder block after being discharged from the oil pump. The lubricating oil supplied through is guided. The in-shaft oil passage 41 supplies the lubricating oil of the supply passage 40 to the supported surfaces 14 to 16 and the first to third of the second to fourth journals J2 to J4 other than the first journal J1 in which the supply passage 40 is formed. Guide to the support surfaces 21 to 23 of the crank pins P1 to P3. Here, the supported surfaces 13 to 16 are surfaces formed by outer peripheral surfaces of the journals J1 to J4 and supported by the bearing surfaces of the plain bearings 31 to 34, and the supporting surfaces 21 to 23 are respectively crankpins P1. It is a surface configured by the outer peripheral surface of P3 to support the bearing surface of the plain bearing 12. The in-shaft oil passage 41 includes holes H1 to H7 formed in the crankshaft 1 by machining such as drilling.

  The four journals J1 to J4 flow from the inlet 42 and the first journal J1 as the primary journal in which the inlet 42 and the supply path 40 of the in-shaft oil passage 41 into which the lubricating oil supplied from the oil pump flows are formed. The second and third journals J2 to J4 are used as secondary journals through which the lubricating oil is guided to the supported surfaces 14 to 16 through the in-shaft oil passage 41.

  The supply path 40 is constituted by an annular groove extending in the circumferential direction on the outer peripheral surface of the first journal J1, and the lubricating oil in the supply path 40 is directly guided to the supported surface 13 of the first journal J1, and the supported surface. An oil film is formed between the bearing surface 31a1 and 31b1 of the plain bearing 31. The inlet 42 is formed to open on the wall surface of the supply path 40 so as to open to the supply path 40. Then, the lubricating oil from the main gallery is supplied to the supply passage 40 through an oil passage 38 formed in the bearing portion B1 and an oil passage 39 formed in the plain bearing 31.

  1 to 3, the in-shaft oil passage 41 has an inlet 42 and extends in the axial direction to reach the fourth journal J4 sequentially from the first journal J1 through the second journal J2 and the third journal J3. A passage 43, a pin passage 45 that is connected to the first connecting portion 44 of the main passage 43 and guides the lubricating oil in the main passage 43 to the support surfaces 21 to 23 of the first to third crankpins P1 to P3; It is composed of a journal passage 47 that is connected to the second connecting portion 46 of 43 and guides the lubricating oil in the main passage 43 to the supported surfaces 14 to 16 of the second to fourth journals J2 to J4.

  In this embodiment, the pin passage 45 formed in each of the crank pins P1 to P3 is formed in the first and second pin portions P1a, P1b; P2a, P2b; P3a, P3b, respectively. They are formed in the second to fourth journals J2 to J4, respectively. And the 1st connection part 44 is located in the channel | path part formed in each crankpin P1-P3 in the main channel | path 43, and in this embodiment, the two 1st connection parts 44 are respectively the 1st, 2nd pin part. P1a, P1b; P2a, P2b; passage portions formed in P3a, P3b. Further, the second connecting portion 46 is located in a passage portion formed in each of the journals J1 to J4 in the main passage 43.

  Then, the lubricating oil of each pin passage 45 is guided to the support surfaces 21 to 23 of each crankpin P1 to P3, and an oil film is formed between the support surfaces 21 to 23 and the bearing surface of the plain bearing 12, Lubricating oil in each journal passage 47 is guided to the supported surfaces 14 to 16 of the second to fourth journals J2 to J4, and the supported surfaces 14 to 16 and the bearing surfaces of the plain bearings 32 to 34 are connected to each other. An oil film is formed between them.

  The main passage 43 has an inlet 42 and introduces an inlet passage 50 for introducing lubricating oil from the inlet 42 to a first passage 51 described later, and the inlet 42 and the lubricating oil from the inlet 42 first flow in through the inlet passage 50. A first passage 51 in which the lubricating oil is pressurized by centrifugal force and flows between the first connection portion 44 of any one of the first crankpins P1 which is the first connection portion 44 of the pin passage 45; The second passage 52 extends between the connection portion 44 and the second connection portion 46. Here, the introduction passage 50, the first and second passages 51, 52 extend at positions away from the rotation center line L over the entire passage (see FIG. 3).

  The introduction passage 50 extends linearly to the first journal J1 in parallel with the rotation center line L and is connected to the inflow portion 51a (see FIGS. 1 and 2) of the first passage 51. The introduction passage 50 is constituted by a hole H1 formed from the end face 18 in the axial direction of the first journal J1. Therefore, the introduction passage 50 is connected to the first passage 51 at a position radially inward from the supported surface 13 of the first journal J1.

  The first passage 51 is an introduction passage from the first journal J1 toward the first crank pin P1 adjacent to the first journal J1, more specifically toward the first and second pin portions P1a and P1b. Lubricating oil flows outwardly in the radial direction and axially in almost the entire passage from 50 to both first connecting portions 44.

  In this specification or claims, the outward passage means a passage in which the rate of increase in hydraulic pressure due to centrifugal force is greater than the rate of decrease in hydraulic pressure due to centrifugal force, and the inward passage refers to centrifugal force. It means a passage in which the rate of increase in hydraulic pressure due to is less than the rate of decrease in hydraulic pressure due to centrifugal force.

  The second passage 52 is connected to the first passage portion 61 extending from the first connection portion 44 to the second connection portion 46 from the first crank pin P1 toward the second journal J2, and is connected to the first passage portion 61 and the second passage 52. A second passage portion 62 extending from the second connecting portion 46 to the first connecting portion 44 from the journal J2 toward the second crankpin P2, and connected to the second passage portion 62 and from the second crankpin P2 to the third journal J3 A third passage portion 63 extending from the first connection portion 44 to the second connection portion 46, and a second connection portion 46 connected to the third passage portion 63 and from the third journal J3 toward the third crankpin P3. From the first connecting portion 44 to the second connecting portion 46 from the third crankpin P3 toward the fourth journal J4. And a fifth passage portion 65. Here, the first, third, and fifth passage portions 61, 63, and 65 are inward passages in which the lubricating oil flows almost radially inward and in the axial direction. The passage portions 62 and 64 are outward passages in which the lubricating oil flows almost radially outward and in the axial direction.

  The first passage 51 is formed by a straight hole H2 machined from the crank arm 3a and a part of the straight hole H3 machined from the crank arm 2a, and the first passage portion 61 is formed by the hole H3. The portion 62 is processed by the straight hole H4 processed from the crank arm 4a, the third passage portion 63 is processed by the straight hole H5 processed from the crank arm 4a, and the fourth passage portion 64 is processed from the crank arm 7a. Due to the straight holes H6, the fifth passage parts 65 are respectively constituted by straight holes H7 machined from the crank arm 6a. A plug is press-fitted into the open end of each hole H1 to H7, and the holes H1 to H7 are closed by the plug.

  As well shown in FIG. 3, the first passage 51 and the second passage 52 are lubricated from the inflow portion 51a until reaching the journal passage 47 of the fourth journal J4 connected to the main passage 43 at the most downstream position. Along the oil flow, as it extends in the axial direction, it extends in the circumferential direction around the rotation center line L to form a spiral passage. Here, the passage is spiral means that the passage extends in the circumferential direction around the rotation center line L as the passage extends in the axial direction, and the angular range extending in the circumferential direction may be 360 ° or less. The direction in which the main passage 43 extends in the circumferential direction in the flow direction of the lubricating oil is a direction opposite to the rotational direction R of the crankshaft 1, and the lubricating oil bends in the counter-rotating direction and the first and second passages 51. , 52.

  Further, the entire passages of the first and second passages 51 and 52 correspond to the distance from the rotation center line L to the inflow portion 51a of the first passage 51 (in FIG. 3, the radius of a circle drawn by a two-dot chain line). In this embodiment, in the vicinity of the second connection portion 46 that is the portion closest to the rotation center line L, the inflow portion from the rotation center line L is formed. The distance from the rotation center line L is approximately equal to the distance to 51a.

Next, operations and effects of the embodiment configured as described above will be described.
In the plurality of journals J1 to J4 of the crankshaft 1 provided in the internal combustion engine, an inlet 42 of an in-shaft oil passage 41 into which lubricating oil supplied from the oil pump flows is formed and lubrication supplied from the oil pump. No. 1 journal J1 in which oil is guided to its supported surface 13 and Nos. 2 to 4 journals J2 to J4 in which lubricating oil is guided to its supported surfaces 14 to 16 through an in-shaft oil passage 41, The in-shaft oil passage 41 formed in the crankshaft 1 includes a main passage 43 having an inlet 42, a pin passage 45, and a journal passage 47. The main passage 43 includes an inlet 42 and lubricating oil from the inlet 42. A first passage 51 consisting of an outward passage in which the lubricating oil is pressurized by centrifugal force between the first connection portion 44 of the first crank pin P1 to which the pin passage 45 into which the oil flows first is connected, From the rotation center line L of the crankshaft 1 over the entire path between the connecting portion 44 and the second connecting portion 46. By including the second passage 52 extending at the specified position, the lubrication oil flowing from the inlet 42 formed in the first journal J1 is applied to the supported surfaces 14 to 16 of the second to fourth journals J2 to J4. Since it is supplied through the in-shaft oil passage 41, it is not necessary to use a plain bearing having a groove in which lubricating oil is accumulated on the bearing surface as the main bearing, so the supported surfaces 14 of the second to fourth journals J2 to J4 ˜16 and plain bearings 32 to 34 can reduce the amount of leakage of the lubricating oil, so that the leakage of the lubricating oil by the crankshaft 1 and the collision of the crankshaft 1 caused by the collision with the crankshaft 1 can be reduced. Since the power loss can be reduced and the amount of oil supplied from the oil pump can be reduced, the oil pump is downsized.

  Further, the supported surfaces 14 to 16 of the second to fourth journals J2 to J4 and the supporting surfaces 21 to 23 of the first to third crank pins P1 to P3 were pressurized by the centrifugal force in the first passage 51. Since the lubricating oil is supplied, the hydraulic pressure supplied by the oil pump can be reduced correspondingly, and the oil pump can be downsized in this respect as well.

  Further, since the lubricating oil from the first passage 51 flows through the second passage 52 passing through the position away from the rotation center line L in the whole passage, the lubricating oil is directed radially inward from the viewpoint of passage formation. Even when the second passage 52 is formed so as to flow, the decrease in hydraulic pressure due to the centrifugal force in the second passage 52 is suppressed, and the supported surfaces 14 to 16 of the second to fourth journals J2 to J4 and the plane Even if the supply hydraulic pressure of the oil pump is set low between the bearings 32 to 34 and further between the support surfaces 21 to 23 of the crank pins P1 to P3 and the plain bearing 12, the required amount of oil is lubricated. Oil can be supplied reliably.

  In addition, since the oil pump driven by the power of the crankshaft 1 can be reduced in size, the pump driving power can be reduced, and further power loss due to sliding resistance in the rotor of the oil pump can be reduced. The power loss of the crankshaft 1 can be reduced.

  The inlet 42 of the in-shaft oil passage 41 opens into a supply passage 40 constituted by an annular groove formed in the circumferential direction on the supported surface 13 of the first journal J1, so that the second through fourth journals J2 In addition to the reduction in the amount of leakage of lubricating oil from between J4 and the plain bearings 32-34, in the first journal, the lubricating oil supplied from the oil gallery flows into the in-shaft oil passage 41. The amount of lubricating oil leakage from between the supported surface 13 of the first journal J1 and the plain bearing 31 is also reduced, so that the power loss of the crankshaft 1 is reduced and the oil pump is reduced in size. Enhanced. Moreover, the area of the plain bearings 32 to 34 can be increased by the amount of the groove where the lubricating oil does not accumulate, thereby improving the reliability of the plain bearings 32 to 34, or the width of the plain bearings 32 to 34. , And accordingly, the width in the axial direction of the crank webs W1a, W1b; W2a, W2b; W3a, W3b can be increased to increase the rigidity. Since all of the journals of the crankshaft 1 are secondary journals except for one primary journal, the effect of reducing the amount of lubricating oil leakage due to the formation of the in-shaft passage 41 is most effective. Is done.

  The main passage 43 is formed by the first passage 51 and the second passage 52 into a spiral passage that extends in the circumferential direction around the rotation center line L as it extends in the axial direction. Even if there are three journals J2, J3, and J4 as secondary journals that are supplied via this, and the in-shaft oil passage 41 is formed long in the axial direction, the fourth journal J4 at the most downstream position from the first journal J1. In the state where the decrease in the hydraulic pressure due to the centrifugal force in the second passage 52 is suppressed, the lubricating oil can be supplied, and the passages in the first and second passages 51 and 52 are sharply bent. Since the hydraulic pressure loss due to the passage shape is reduced, the supported surfaces 14 to 16 of the second to fourth journals J2 to J4 and the crank pins to the most downstream position of the in-shaft oil passage 41 are reduced. The required amount of oil can be reliably supplied to the support surfaces 21 to 23 of P1 to P3.

  The lubricating oil flows in the first and second passages 51 and 52 while being bent in the circumferential direction in the direction opposite to the rotational direction R of the crankshaft 1, so that the lubricating oil is first fed by the rotation of the crankshaft 1. , The oil pressure in the shaft oil passage 41 is promoted and the shaft oil passage 41 extends long in the axial direction even when the shaft oil passage 41 extends in the axial direction. The required amount of oil can be reliably supplied to No. 2 to No. 4 J2 to J4 and the crankpins P1 to P3 as secondary journals up to the most downstream position.

  The entire passage of the second passage 52 is separated from the rotation center line L by a distance greater than the distance from the rotation center line L to the inflow portion 51a of the first passage 51, so that the lubricating oil in the second passage 52 is reduced in diameter. Even when flowing inward in the direction, the decrease in the hydraulic pressure due to the centrifugal force is prevented or suppressed less than the increase due to the centrifugal force in the first passage 51, so the decrease in the hydraulic pressure in the in-shaft oil passage 41 is prevented. Even if the air mixed in the lubricating oil is further suppressed and stays in the middle of the oil passage 41 in the shaft, the hydraulic pressure that overcomes the air pressure can be secured, so the second to fourth journals J2 to J4 and the crankpins P1 to The required amount of lubricating oil can be supplied to P3 more reliably.

  Next, a second embodiment of the present invention will be described with reference to FIGS. The second embodiment is different from the first embodiment in the type of the internal combustion engine, and the shape of the crankshaft is accordingly different, but the basic configuration thereof is the same. Therefore, description of the same part is omitted or simplified, and different points will be mainly described. In addition, about the same member as the member of 1st Embodiment, or the corresponding member, the same term or code | symbol was used as needed.

  5 and 6, the crankshaft 70 is provided in an in-line four-cylinder four-stroke internal combustion engine. The internal combustion engine includes an engine body including a cylinder block, a cylinder head, and an oil pan in which four cylinders are fitted in series so that a piston can be reciprocated. A crankcase includes a crankshaft 70. A crank chamber to be accommodated is formed.

  The crankshaft 70 includes five journals consisting of first to fifth journals J1 to J5 separated in the axial direction, and four pairs of crank webs W1a, W1b; W2a, W2b; W3a, W3b; W4a, W4b The four first to fourth crankpins P1 to P4 are an integral crankshaft integrally formed of metal. A pair of crank webs W1a, W1b; W2a, W2b; W3a, W3b; W4a, W4b each have a crank arm and a balance weight, and each pair of crank webs W1a, W1b; W2a, W2b; W3a , W3b; crank arms of W4a and W4b are connected by crank pins P1 to P4. Each crank pin P1 to P4 pivotally supports a connecting rod 11 connected to the piston via a plain bearing 12 as a radial bearing. The journals J1 to J5 are rotatably supported by the plain bearings 31 to 35 of the bearing portions B1 to B5 on the supported surfaces 13 to 17, and the crank pins P1 to P4 are supported on the support surfaces 21 to At 24, pivot connecting rod 11.

  At one shaft end of the crankshaft 70, in order from the vicinity of the first journal J1, there are provided mounting portions for drive sprockets that drive the camshaft of the oil pump and the valve gear, and the crank pulley 26 is further mounted. A flywheel mounting portion 27 is provided at the other shaft end of the crankshaft 70.

  The crankshaft 70 is rotatably supported by a bearing device including five first to fifth bearing portions B1 to B5 by first to fifth journals J1 to J5. Each bearing part B1-B5 is comprised from the plain bearings 31-35 and a bearing support member. The bearing support member includes a bearing wall 36 which is a part of the cylinder block, and a bearing cap 37 fastened to each bearing wall 36. Each plain bearing 31-35 consisting of a pair of bearing halves 31a-35a, 31b-35b is a grooveless plain bearing which is a bearing in which a groove for retaining lubricating oil is not formed on the bearing surface of each bearing half. .

  As shown in FIG. 7, in the bearing halves 31a and 31b of the plain bearing 31 supporting the first journal J1, the lubricating oil from the oil passage 38 formed in the bearing wall 36 is guided to the bearing surfaces 31a1 and 31b1. An oil passage 39 is formed. Further, as shown in FIG. 5, the third bearing portion B3 has a pair of bearing walls 36 and a bearing cap 37 held at each end in the axial direction of the plain bearing 33 that supports the third journal J3. Thrust bearings 71a and 71b; 72a and 72b are provided.

  A supply passage 40 and an in-shaft oil passage 41 are formed in the crankshaft 70. Lubricating oil supplied through a main gallery formed in the cylinder block is guided to the supply path 40. The oil passage 41 in the shaft supports the lubricating oil in the supply passage 40 on the second, fourth journals J2, J4 other than the first, third, fifth journals J1, J2, J3 in which the supply passage 40 is formed. The surfaces 14 and 16 and the in-shaft oil passage 41 leading to the support surfaces 21 to 24 of the crank pins P1 to P4 are formed.

  The five journals J1 to J5 are the first and fifth journals J1, J1 as primary journals in which the inlet 42 of the in-shaft oil passage 41 and the supply passage 40 into which the lubricating oil supplied from the oil pump flows are formed. No. 2 and No. 4 journals J2 and J4 as secondary journals in which the lubricating oil flowing in from the inlet 42 is guided to the supported surfaces 14 and 16 via the in-shaft oil passage 41, and the supply passage 40 are formed. And the third journal, J3. Therefore, in the five journals J1 to J5, the first and fifth journals J1 and J5 and the second and fourth journals J2 and J4 are compared to the third journal J3, which is the central journal located in the center in the axial direction. Are arranged symmetrically.

  Referring to FIGS. 5 to 7, the supply path 40 is constituted by an annular groove extending in the circumferential direction on the outer peripheral surface of the first, third, and fifth journals J1, J3, and J5. In the supply passage 40, the lubricating oil from the main gallery is filled with an oil passage 38 formed in the bearing wall 36 and the first bearing half supporting the first, third, fifth journals J1, J3, J5. It is supplied through an oil passage 39 formed in the bodies 31a, 33a, 35a. Further, in the first and fifth journals J1 and J5, the inlet 42 is formed so as to open to the bottom wall surface of the supply path 40 so as to open to the supply path 40.

  In the first and fifth journals J1 and J5, the lubricating oil in the supply passage 40 is directly guided between the supported surfaces 13 and 17 and the bearing surfaces of the plain bearings 31 and 35, and in the third journal J3. The lubricating oil in the supply path 40 is a pair of crank webs W2b, W3a and thrust bearings 71a, 71b; 72a, 72b between the supported surface 15 and the bearing surface of the plain bearing 33 and adjacent to the third journal J3. In between, you will be led directly.

  The in-shaft oil passage 41 is formed substantially symmetrically in the axial direction with respect to the third journal J3, has a separate inlet 42, and includes first and second oil passages 81 and 82 which are independent from each other. Hereinafter, for the sake of convenience, the first oil passage 81 will be mainly described, and the components corresponding to the second oil passage 82 will be described in parentheses as necessary.

  The first (second) oil passage 81 (82) has an inlet 42 and extends in the axial direction from the first (fifth) journal J1 (J5) to the second (fourth) journal J2 (J4). Lubricating oil in the main passage 43 connected to the passage 43 and the first connecting portion 44 is supported by the support surfaces 21 (24) of the No. 1 (No. 4) and No. 2 (No. 3) crank pins P1 (P4) and P2 (P3). ), 22 (23), the pin passage 45 and the second connecting portion 46 to connect the lubricating oil of the main passage 43 to the supported surface 14 (16) of the second (fourth) journal J2 (J4) And a journal passage 47 for guiding.

  The pin passage 45 is formed in each of the crank pins P1 to P4, and the journal passage 47 is formed in the second and fourth journals J1 and J4. The first connection portion 44 is located in a passage portion formed in each crankpin P1 to P4 in the main passage 43, and the second connection portion 46 is formed in the second and fourth journals J2 and J4 in the main passage 43. Located in the passage part.

  In the first (second) oil passage 81 (82), the main passage 43 includes an introduction passage 50, a first passage 51, and a second passage 52. Here, the introduction passage 50, the first and second passages 51 and 52 extend at positions away from the rotation center line L of the crankshaft 70 over the entire passage (see FIG. 6).

  The introduction passage 50 extends linearly inward in the radial direction toward the rotation center line L in a state intersecting with a plane orthogonal to the rotation center line L in the first (5th) journal J1 (J5). The first passage 51 is connected to the inflow portion 51a. Therefore, the introduction passage 50 is connected to the first passage 51 at a position radially inward from the supported surface 13 (17) of the first (fifth) journal J1 (J5).

  First passage 51 is an introduction passage from No. 1 (No. 5) journal J1 (J5) to No. 1 (No. 4) crank pin P1 (P4) adjacent to No. 1 (No. 5) journal J1 (J5). The first connection portion 44 is an outward passage that is located radially outward from the inflow portion 51a and extends from 50 to the first connection portion 44.

  The second passage 52 extends from the first connection portion 44 to the second connection portion 46 from the first (fourth) crank pin P1 (P4) toward the second (fourth) journal J2 (J4) and has a first connection. From the second passage (fourth) journal J2 (J4), the portion 44 is connected to the first passage portion 61 and the first passage portion 61 is an inward passage located radially inward of the second connection portion 46. Extending from the second connecting portion 46 to the first connecting portion 44 toward the second (third) crank pin P2 (P3), the first connecting portion 44 is located radially outward from the second connecting portion 46. And a second passage portion 62 that is an outward passage.

  The first and second passages 51 and 52 are provided with lubricating oil until they reach the pin passage 45 of the second (third) crank pin P2 (P3) connected to the main passage 43 at the most downstream position from the inflow portion 51a. Along the flow, as it extends in the axial direction, it extends in the circumferential direction around the rotation center line L to form a spiral passage. The direction in which the main passage 43 extends in the circumferential direction in the flow direction of the lubricating oil is a direction opposite to the rotational direction R of the crankshaft 70, and the first and second passages 51 are bent while the lubricating oil is bent in the counter-rotating direction. , 52.

According to the second embodiment, the same operations and effects as the first embodiment are exhibited, and the following operations and effects are exhibited.
The crankshaft 70 has five journals J1 to J5, and the first and fifth journals J1 and J5 and the second and fourth journals J2 and J4 correspond to the third journal J3 located in the center in the axial direction. By arranging them symmetrically, the in-shaft oil passage 41 is divided into two systems, the first and second oil passages 81 and 82, on the support surfaces 22 and 23 of the crank pins P2 and P3 at the most downstream position. It is easy to supply the required amount of lubricating oil, and it is possible to supply almost equal amount of lubricating oil to the No. 2 and No. 4 journals J2 and J4 arranged symmetrically, so the oil passage in the shaft 41 improves the stability of lubrication on the supported surfaces 14 and 16 of the second and fourth journals J2 and J4 to which the lubricating oil is supplied and the supporting surfaces 21 to 24 of the crank pins P1 to P4.

  The inlet 42 is connected to the first passage 51 through an introduction passage 50 extending linearly inward in the radial direction toward the rotation center line L in a state of intersecting a plane orthogonal to the rotation center line L. Since the position of the inflow portion 51a of the first passage 51 connected to the introduction passage 50 can be set to a position close to the rotation center line L by the shortest length of the introduction passage 50, hydraulic loss in the introduction passage 50 is reduced. Further, since the pressurizing action by the centrifugal force on the lubricating oil in the first passage 51 can be increased, the required amount of lubricating oil can be supplied more reliably.

  Thrust bearings 71a, 71b, 72a, 72b for restricting the axial movement of the crankshaft 70 are provided in the bearing portion B3 that supports the third journal J3 in which the supply path 40 is formed. Since the lubricating oil from the supply passage 40 through which the lubricating oil supplied from the main gallery is guided via the bearing portion B3 is directly supplied to 72a and 72b, the thrust bearing 71a, The required amount of lubricating oil can be reliably supplied to 71b, 72a and 72b.

  Next, third and fourth embodiments of the present invention will be described with reference to FIGS. The third and fourth embodiments are different from the second embodiment in the arrangement of journals serving as primary and secondary journals, and the others have basically the same configuration. Therefore, description of the same part is omitted or simplified, and different points will be mainly described. In addition, about the member same as the member of 1st Embodiment, or the corresponding member, the same code | symbol was used as needed.

  Referring to FIG. 8, in the third embodiment, the five journals J1 to J5 included in the crankshaft 70 are the second and fourth journals J2 and J4 as the primary journals and the first and fifth journals as the secondary journals. It consists of J1 and J5 and the third journal J3 as a tertiary journal. Therefore, in the five journals J1 to J5, the first and fifth journals J1 and J5 and the second and fourth journals J2 and J4 are compared to the third journal J3, which is the central journal located in the center in the axial direction. Are arranged symmetrically.

  Referring also to FIG. 9, the supply path 40 is formed in the second, third, and fourth journals J2, J3, and J4, and the inlet 42 opens to the supply path 40 in the second and fourth journals J2 and J4. Formed. The structure of the third journal J3 is the same as that of the second embodiment.

  The in-shaft oil passage 41 is formed substantially symmetrically in the axial direction with respect to the third journal J3, has a separate inlet 42, and includes first and second oil passages 81 and 82 which are independent from each other. Hereinafter, for the sake of convenience, the first oil passage 81 will be mainly described, and the components corresponding to the second oil passage 82 will be described in parentheses as necessary.

  The first (second) oil passage 81 (82) has an inlet 42 and extends in the axial direction from the second (fourth) journal J2 (J4) to the first (fifth) journal J1 (J5) and 2 Main passage 43 reaching No. (No. 3) crank pin P2 (P3) and lubricating oil in main passage 43 connected to the first connecting portion 44, No. 1 (No. 4), No. 2 (No. 3) crank pin P1 (P4), P2 (P3) support surface 21 (24), lead path 45 leading to 22 (23), and connecting to the second connection 46, the main passage 43 lubricating oil No. 1 (No. 5) It comprises a journal passage 47 that leads to the supported surface 13 (17) of the journal J1 (J5). The journal passage 47 is formed in the first and fifth journals J1 and J5, and the second connecting portion 46 is located in the passage portion formed in the first and fifth journal J1 (J5) in the main passage 43.

  In the first (second) oil passage 81 (82), the main passage 43 includes an introduction passage 50, a first passage 51, and a second passage 52. Here, the introduction passage 50 and the first and second passages 51 and 52 extend at positions away from the rotation center line L of the crankshaft 70 over the entire passage.

  In the second (fourth) journal J2 (J4), the introduction passage 50 extends linearly inward in the radial direction toward the rotation center line L in a state intersecting with a plane orthogonal to the rotation center line L. It connects with the inflow part 51a (refer FIG. 9) of the 1st channel | path 51. FIG.

  The first passage 51 starts from the second (fourth) journal J2 (J4) to the first, second (third, fourth) crank pins P1, P2 adjacent to the second (fourth) journal J2 (J4). (P3, P4) extends from the introduction passage 50 to the first connection portion 44, and the first connection portion 44 is an outward passage that is located radially outward from the inflow portion 51a.

  The second passage 52 extends from the first connecting portion 44 to the second connecting portion 46 from the first (fourth) crank pin P1 (P4) toward the first (fifth) journal J1 (J5). The two connection portions 46 are inward passages located radially inward from the first connection portion 44.

According to the third embodiment, the same operations and effects as the first embodiment are exhibited, and the following operations and effects are exhibited.
The first and fifth journals J1 and J5, which are located at the end of the journals J1 to J5 of the crankshaft 70 and are closest to the crankcase among the journals J1 to J5, have their supported surfaces 13 , 17 is not formed with an annular groove for storing lubricating oil, and its rigidity is increased, so that the clearance between the first and fifth journals J1, J5 and the plain bearings 31, 35 is increased. And the occurrence of vibration and sound based on the clearance is suppressed.

Next, a fourth embodiment of the present invention will be described with reference to FIGS.
In the fourth embodiment, the crankshaft 70 has a single primary journal. Specifically, the five journals J1 to J5 are composed of a third journal J3 as a primary journal and first, second, fourth, and fifth journals J1, J2, J4, and J5 as secondary journals. . Therefore, in the five journals J1 to J5, the secondary journals J1, J2, J4, and J5, the first, second, fourth, and fifth journals J1, J2, J4, and J5 are centered in the axial direction. They are arranged symmetrically with respect to the third journal J3 located.

  The supply path 40 is formed by an annular groove extending in the circumferential direction on the outer peripheral surface of the third journal J3. In the third journal J3, the lubricating oil in the supply passage 40 flows between the supported surface 15 and the bearing surface of the plain bearing 33, and a pair of crank webs W2b, W3a and thrust bearings 71a, 71b, 72a, 72b. Further, the lubricating oil from the main gallery is supplied to the supply passage 40, and the inlet 42 is formed on the bottom wall surface of the supply passage 40 so as to open to the supply passage 40.

  The in-shaft oil passage 41 is formed of first and second oil passages 81 and 82 that are substantially symmetrical in the axial direction with respect to the third journal J3 and share the inlet 42. Hereinafter, for the sake of convenience, the first oil passage 81 will be mainly described, and the components corresponding to the second oil passage 82 will be described in parentheses as necessary.

  The first (second) oil passage 81 (82) extends in the axial direction from the inlet 42 and passes from the third journal J3 through the second (fourth) journal J2 (J4) to the first (fifth) journal J1 (J5). ), And the support surface 22 of the No. 2 and No. 1 (No. 3 and No. 4) crank pins P2 and P1 (P3 and P4) connected to the first connecting portion 44 and the lubricating oil in the main passage 43. , 21 (23, 24), the pin passage 45 and the second connecting portion 46 to connect the lubricating oil in the main passage 43 to the second, first (fourth, fifth) journals J2, J1 (J4, J5) journal passage 47 that leads to supported surfaces 14, 13 (16, 17).

  The journal passage 47 is formed in the first, second, fourth, and fifth journals J1, J2, J4, and J5, and the second connecting portion 46 is the first, second, fourth, and fifth in the main passage 43. Located in the passage part formed in the journals J1, J2, J4, J5.

  In the first (second) oil passage 81 (82), the main passage 43 includes an introduction passage 50, a first passage 51, and a second passage 52. Here, the introduction passage 50 and the first and second passages 51 and 52 extend at positions away from the rotation center line L of the crankshaft 70 over the entire passage.

  The introduction passage 50 extends linearly inward in the radial direction toward the rotation center line L in the state of intersecting with the plane orthogonal to the rotation center line L in the third journal J3, and the inflow portion of the first passage 51 Connect to 51a (see FIG. 11).

  The first passage 51 extends from the introduction passage 50 to the first connection portion 44 from the third journal J3 toward the second (third) crank pin P2 (P3) adjacent to the third journal J3. The connecting portion 44 is an outward passage positioned radially outward from the inflow portion 51a.

  The second passage 52 extends from the first connecting portion 44 to the second connecting portion 46 from the second (third) crank pin P2 (P3) to the second (fourth) journal J2 (J4) and has a second connection. From the second passage (fourth) journal J2 (J4), the first passage portion 61 is an inward passage that is located radially inward of the first connection portion 44 and the first passage portion 61 is connected to the first passage portion 61. The first connecting portion 44 extends from the second connecting portion 46 toward the first connecting portion 44 toward the first (fourth) crank pin P1 (P4), and the first connecting portion 44 is located radially outward from the second connecting portion 46. A second passage portion 62 that is an outward passage, and a first passage from the first (fourth) crank pin P1 (P4) to the first (fifth) journal J1 (J5) are connected to the second passage portion 62. A third passage portion 63 that is an inward passage extending from the connection portion 44 to the second connection portion 46 and in which the second connection portion 46 is located radially inward of the first connection portion 44. It is.

  The first and second passages 51 and 52 flow the lubricating oil until reaching the journal passage 47 of the first (fifth) journal J1 (J5) connected from the inflow portion 51a to the main passage 43 at the most downstream position. Along the axis, the axis extends in the circumferential direction around the rotation center line L to form a spiral passage. The direction in which the main passage 43 extends in the circumferential direction in the flow direction of the lubricating oil is a direction opposite to the rotational direction R of the crankshaft 70, and the first and second passages 51 are bent while the lubricating oil is bent in the counter-rotating direction. , 52.

According to the fourth embodiment, the same operations and effects as the third embodiment are exhibited, and the following operations and effects are exhibited.
Of the journals of the crankshaft 70, all but one primary journal are secondary journals, and as in the first embodiment, the effect of reducing the amount of lubricating oil leakage due to the formation of the in-shaft passage 41 is provided. Is played most effectively.

Hereinafter, an embodiment in which a part of the configuration of the above-described embodiment is changed will be described with respect to the changed configuration.
The introduction passage 50 and the first passage 51 may be formed so as to have a passage cross-sectional area larger than that of the second passage 52. In this case, the lubricating oil from the main gallery flows into the in-shaft oil passage 41. Therefore, the required amount of oil can be more reliably supplied to the most downstream journal oil passage or pin oil passage in the main passage.

  The inlet 42 may be formed in the end face 18 in the axial direction of the first journal J1. The supply path 40 may be formed in the bearing portion B1 instead of the first journal J1. Further, the main passage may not have the introduction passage.

  In the second to fourth embodiments, the position of the inflow portion 51a of the first passage 51 connected to the introduction passage 50 may be set to a position that intersects the rotation center line L.

  Although the internal combustion engine is used for a vehicle in each of the embodiments described above, the internal combustion engine may be used for a ship propulsion device such as an outboard motor including a crankshaft 70 oriented in the vertical direction. The internal combustion engine may be a single-cylinder internal combustion engine including a crankshaft 70 having one crankpin P1, P2, P3, or P4, or a multi-cylinder internal combustion engine other than 4-cylinder and 6-cylinder. Further, the machine including the crankshaft 70 may be a machine other than the internal combustion engine, for example, a compressor.

1 is a perspective view of a crankshaft of a V-type 6-cylinder internal combustion engine to which the present invention is applied, showing a first embodiment of the present invention. It is a side view of the crankshaft of FIG. FIG. 3 is a view taken in the direction of arrow III in FIG. 2. It is principal part sectional drawing in the 1st journal of the crankshaft of FIG. 1, (A) is sectional drawing in the AA of (B), (B) is BB of (A). It is sectional drawing in a line. FIG. 6 is a side view of a crankshaft of an in-line four-cylinder internal combustion engine to which the present invention is applied, showing a second embodiment of the present invention. FIG. 6 is a schematic view of the crankshaft of FIG. 5 as viewed in the direction of arrow VI in FIG. It is principal part sectional drawing in the 1st journal of the crankshaft of FIG. 5, (A) is sectional drawing in the AA of (B), (B) is BB of (A). It is sectional drawing in a line. FIG. 6 shows a third embodiment of the present invention and is a side view of a crankshaft corresponding to FIG. 5. FIG. 9 is a schematic diagram corresponding to FIG. 6 in the crankshaft of FIG. 8. FIG. 6 is a side view of a crankshaft showing a fourth embodiment of the present invention and corresponding to FIG. 5. FIG. 11 is a schematic view corresponding to FIG. 6 in the crankshaft of FIG. 10.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,70 ... Crankshaft, 2a-7a ... Crank arm, 2b-7b ... Balance weight, 11 ... Connecting rod, 12 ... Plain bearing, 13-17 ... Supported surface, 18 ... End surface, 21-24 ... Support surface, 26 ... Crank pulley, 27 ... Mounting part,
31-35 ... Plain bearing, 36 ... Bearing wall, 37 ... Bearing cap, 38, 39 ... Oil passage, 40 ... Supply passage, 41 ... In-shaft oil passage, 42 ... Inlet, 43 ... Main passage, 44 ... First connection 45, pin passage 45, 46 second connection portion, 47 journal passage, 50 introduction passage, 51 first passage, 52 second passage, 61-65 passage portions, 71a, 71b, 72a, 72b ... thrust bearing, 81 ... first oil passage, 82 ... second oil passage,
J1-J5 ... Journal, W1a, W1b; W2a, W2b; W3a, W3b; W4a, W4b ... Crank web, P1-P4 ... Crank pin, L ... Rotation center line, B1, B2, B3, B4 ... Bearing part, H1 ~ H7 ... hole, R ... rotation direction.

Claims (6)

A plurality of predetermined number of bearing portions, a crankshaft having the predetermined number of journals supported by the predetermined number of the bearing portions, and one or more crank pins, and a supply device for supplying lubricating oil, Each journal is rotatably supported by a main bearing comprising a plain bearing of each bearing portion on its supported surface, and the crank pin pivots a connecting member connected to a reciprocating member on its supporting surface. In the machine in which the crankshaft is formed with an in-shaft oil passage for guiding lubricating oil to the support surface,
In the predetermined number of the journals, an inlet of the oil passage in the shaft into which the lubricating oil supplied from the supply device flows is formed, and the lubricating oil supplied from the supply device is guided to the supported surface. A primary journal, and a secondary journal through which the lubricating oil flowing in from the inlet is guided to the supported surface through the in-shaft oil passage, the in-shaft oil passage includes a main passage having the inlet; and A pin passage that is connected to the first connection portion of the main passage and guides the lubricating oil of the main passage to the support surface of the crankpin, and a lubricating oil of the main passage is connected to the second connection portion of the main passage. A journal passage leading to a supported surface of the secondary journal, and the main passage is connected to the inlet and the pin passage through which lubricating oil from the inlet first flows in through the inflow portion . Lubricating oil is applied to the connecting part by centrifugal force. A first passage formed of an outward passage, and a second passage extending between the first connection portion and the second connection portion at a position away from the rotation center line of the crankshaft over the entire passage. It includes,
The machine according to claim 1, wherein the entire passage of the second passage is separated from the rotation center line by a distance greater than or equal to a distance from the rotation center line to the inflow portion of the first passage .   2. The main passage is formed by the first passage and the second passage into a spiral passage that extends in the circumferential direction around the rotation center line as it extends in the axial direction. Machine.   The machine according to claim 2, wherein the lubricating oil flows in the first passage and the second passage while being bent in a circumferential direction in a direction opposite to a rotation direction of the crankshaft.   The inlet is connected to the first passage through an introduction passage extending linearly inward in the radial direction toward the rotation center line in a state of intersecting a plane orthogonal to the rotation center line. A machine according to any one of claims 1 to 3.   The predetermined number is an odd number of 5 or more, and the primary journal and the secondary journal are respectively arranged symmetrically with respect to a central journal located in the center in the axial direction. The machine according to claim 4.   The predetermined number of the journals is composed of one primary journal and the remaining secondary journals, and the inlet is an annular groove formed in a circumferential direction on a supported surface of the primary journal. 6. The opening according to claim 1, wherein all the secondary journals are supported by the bearing portion by the main bearing in which a groove for lubricating oil is not formed on the bearing surface. Item 1. The machine according to item 1.

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