JP2014043783A - Lubricant supply structure of internal combustion engine - Google Patents

Abstract

An oil supply structure for an internal combustion engine in which an oil chamber is formed on the outer side in the axial direction of a bearing member of a crank journal portion, the oil seal of the oil chamber is difficult to apply hydraulic pressure, and the degree of freedom in designing the oil chamber capacity is high.
A crank journal 51bL of a crankshaft 51 is supported on a crankcase 5a by a bearing member 54, and an oil seal 101 is attached to the crankshaft on the outer side in the axial direction from the crank journal to form an oil chamber 100. An oil sump 105 is formed between the outer surface 103 of the crank web 51cL and the side plate 104 attached to the outer surface, and the oil sump 105 passes through an oil groove 106 formed on the outer peripheral surface of the crank journal portion. In the lubricating oil supply structure of the internal combustion engine, the lubricating oil is communicated with the oil chamber, and the lubricating oil is introduced into the oil chamber and supplied to a predetermined lubricating location from the oil reservoir through the hollow portion 107 in the crank pin 51a. A discharge hole 108 for discharging a predetermined amount or more of lubricating oil was formed in the side plate 104.
[Selection] Figure 7

Description

  The present invention relates to a lubricating oil supply structure for an internal combustion engine, and more particularly to a lubricating oil supply structure in which an oil chamber is formed on the axially outer side of a bearing member that supports a crank journal portion.

As a conventional lubricating oil supply structure for an internal combustion engine, it is mounted between an oil chamber formed between the outer surface of a bearing member (ball bearing) that supports the crank journal portion and the crankcase, and the crankcase and the crankshaft. And an oil seal that keeps the oil chamber side liquid-tight, an oil groove formed on the outer peripheral surface of the crank journal portion, a crank web connected to the crank journal portion, and a side plate attached to the outer surface of the crank web. The oil stored in the oil sump of the crankcase is sucked by the oil pump driven by the crankshaft, and the lubricant discharged from the oil pump is guided to the oil chamber and the oil groove For example, Japanese Patent Application Laid-Open No. H10-228667 discloses a method in which lubricating oil is supplied to an oil sump through the oil sump and supplied to a predetermined lubricating location. It has been.
In what is shown in the following Patent Document 1, when the pressure of the lubricating oil is increased in the oil chamber and the oil reservoir, the pressure is reduced in order to prevent the influence of the displacement of the oil seal or the deterioration of the durability. A crankcase partition is provided between the oil chamber and the oil seal so that the oil seal is not directly affected.

  However, if such a partition wall is provided, not only the structure of the crankcase is complicated, but also the crankcase is increased in size in the axial direction, which may increase the weight. Also, if the partition wall is moved closer to the crank web side in order to prevent enlargement in the axial direction, the size of the oil chamber will be limited, so it will be difficult to secure an oil chamber of sufficient capacity, As a result, the environment is likely to increase pressure.

Japanese Patent No. 4233680 (FIGS. 2 to 4 and 6)

  The present invention prevents the pressure in the oil chamber and the oil reservoir from increasing more than necessary in the lubricating oil supply structure in which the oil chamber is formed on the outer side in the axial direction of the bearing member that supports the crank journal portion in view of the above prior art. It is possible to prevent the oil seal from being subject to oil pressure with a simple structure without forming a partition wall or the like in the crankcase, and to increase the degree of freedom in designing the capacity of the oil chamber. It is an object to provide a supply structure.

  In order to solve the above-mentioned problem, the invention according to claim 1 is characterized in that a crank journal of a crankshaft of an internal combustion engine is rotatably supported by a crankcase via a bearing member, and the shaft is more than the crank journal. On the outer side in the direction, an oil seal is mounted between the crankcase and the crankshaft, an oil chamber is formed between the outer surface of the bearing member and the oil seal, and a crank web connected to the crank journal portion is formed. An oil sump is formed between the outer side surface and a side plate attached to the outer side surface, and the oil sump communicates with the oil chamber via an oil groove formed on the outer peripheral surface of the crank journal portion. Lubricating oil is introduced into the oil chamber by an oil pump driven by the crankshaft, and is predetermined from the oil reservoir through a hollow portion in the crankpin. In the lubricating oil supply structure of an internal combustion engine that supplies oil to a lubricating location, the side plate is formed with a discharge hole for discharging the lubricating oil when the amount of lubricating oil in the oil reservoir exceeds a predetermined value. This is a lubricating oil supply structure for an internal combustion engine.

  According to a second aspect of the present invention, in the lubricating oil supply structure for an internal combustion engine according to the first aspect, the bearing member is a seal bearing having a seal member on an outer surface on the oil chamber side, and the side plate is The outer peripheral surface of the crank web near the outer periphery and the oil reservoir side surface of the bearing member on the crank journal portion side are in contact with each other.

  According to a third aspect of the present invention, in the lubricating oil supply structure for an internal combustion engine according to the second aspect, the crank web is provided with the crank pin having the hollow portion with one end opened, and the opening. Is arranged so as to face the oil reservoir, and the discharge hole is provided on the axial center side of the crankshaft with respect to the axial center of the hollow portion.

  According to a fourth aspect of the present invention, in the lubricating oil supply structure for an internal combustion engine according to the second or third aspect, the seal bearing is fitted into the outer race fitted into the crankcase and the crank journal portion. And an inner race of the outer race and a ball member held on the outer periphery of the inner race, and the discharge hole faces between the inner circumference of the outer race and the outer circumference of the inner race. It is provided.

  According to a fifth aspect of the present invention, in the lubricating oil supply structure for an internal combustion engine according to any one of the second to fourth aspects, at least two of the exhaust holes are provided, and one exhaust hole is provided. Further, another discharge hole is provided in a positional relationship in which the phase is shifted by 180 °.

  According to a sixth aspect of the present invention, in the lubricating oil supply structure for an internal combustion engine according to any one of the second to fifth aspects, the crank web includes the hollow portion having one end opened. A pin is provided and the opening faces the oil sump, and the discharge hole is adjacent to the opening of the crank pin and the oil that is first adjacent to the opening in the rotation direction of the crankshaft. It is characterized in that it is provided at a position where it is separated from the groove.

  According to a seventh aspect of the present invention, in the lubricating oil supply structure for an internal combustion engine according to any one of the first to sixth aspects, the lubricating oil supplied by the oil pump is guided to the oil chamber. An oil chamber inlet is provided above the axis of the crankshaft.

According to the lubricating oil supply structure of the internal combustion engine of the first aspect of the invention, since the side plate is formed with the discharge hole for discharging the lubricating oil when the amount of the lubricating oil in the oil sump exceeds a predetermined value, When the lubricant pressure in the oil chamber and oil reservoir rises more than necessary, that is, when more lubricant is supplied than necessary, the lubricant is discharged from the discharge holes formed in the side plate. It is possible to prevent the pressure from increasing more than necessary in the oil reservoir and the oil chamber communicating with the oil reservoir.
Therefore, it is possible to prevent a large hydraulic pressure from being applied to the oil seal with a simple structure without forming a partition wall or the like between the oil chamber and the oil seal. It is possible to prevent the influence of a decrease or the like and increase the degree of freedom in designing the capacity of the oil chamber.

  According to the second aspect of the invention, in addition to the effect of the first aspect of the invention, the bearing member is a sealed bearing, thereby preventing an inadvertent flow of lubricating oil between the oil chamber and the oil reservoir, and the oil chamber. In addition to efficiently guiding the lubricating oil from the oil groove to the oil groove, the side plate comes into contact with the outer surface near the outer periphery of the crank web and the side surface on the oil reservoir side of the journal shaft side of the bearing member. Lubricating oil can be supplied to the oil reservoir and the lubricating oil can be held in the oil reservoir efficiently.

  According to the invention of claim 3, in addition to the effect of the invention of claim 2, in the oil reservoir, the lubricating oil is accumulated from the side far from the axis of the crankshaft by centrifugal force. Since it is provided closer to the crankshaft axis than the hollow shaft center, it is possible to hold a sufficient amount of lubricating oil in the hollow portion in preference to the discharge of the lubricating oil from the discharge hole. Therefore, it is possible to efficiently supply oil to a predetermined lubricating point.

  According to the invention of claim 4, in addition to the effect of the invention of claim 2 or claim 3, the lubricating oil discharged from the discharge hole is a gap portion between the inner periphery of the outer race and the outer periphery of the inner race, that is, Since it is discharged to the ball member housing portion, the lubricating oil is easily discharged from the gap portion. Further, a part of the lubricating oil discharged from the discharge hole can function as a lubricating oil for the seal bearing.

  According to the invention of claim 5, in addition to the effect of the invention of any one of claims 2 to 4, since at least two discharge holes are provided in a positional relationship shifted by 180 °, rotation of the crankshaft Therefore, when the pressure rises more than necessary in the oil reservoir and the oil chamber communicating with the oil reservoir, unnecessary lubricating oil can be discharged quickly.

  According to the invention of claim 6, in addition to the effect of the invention of any one of claims 2 to 5, the discharge hole has an opening of the crankpin and a rotation direction side of the crankshaft with respect to the opening. Therefore, the oil drainage from the oil groove is prevented by preventing the discharge hole from reaching the lubricating oil path from this oil groove to the opening of the crankpin. Inadvertent discharge of the lubricating oil flowing into the cylinder can be prevented, and the lubricating oil can be efficiently guided from the oil groove to the hollow portion of the crank pin.

  According to the invention of claim 7, in addition to the effect of the invention of any one of claims 1 to 6, the oil chamber inlet is provided above the axis of the crankshaft. Therefore, a sufficient amount of oil can be stored in the oil chamber.

1 is a schematic left side view of a motorcycle equipped with a power unit including a lubricating oil supply structure for an internal combustion engine according to an embodiment of the present invention. FIG. 2 is an enlarged view around a power unit with the vehicle body cover removed in the motorcycle of FIG. 1. FIG. 3 is a developed sectional view of the power unit as viewed in the direction of arrows III-III in FIG. 2. FIG. 4 is a right side device arrangement and an oil passage explanatory diagram of the power unit, omitting the illustration of an AC generator and the like, generally in the direction of arrows IV-IV in FIG. FIG. 4 is a left side device arrangement of the power unit and an oil passage explanatory diagram in which the illustration of the belt-type continuously variable transmission or the like is omitted in FIG. It is explanatory drawing of the oil-path connection part in a cylinder block by the VI-VI arrow view in FIG. 3A is an enlarged sectional view around the left crank journal portion and the left main bearing in FIG. 3, and FIG. 3B is a view taken along the line BB in FIG. Note that (A) corresponds to a cross-sectional view taken along the line AA in (B), but the phase of the oil groove and the discharge hole is shifted and shown on the cross section. FIG. 4 is a right side view of the cylinder head as viewed in the direction of arrows VIII-VIII in FIG. 3. It is an expanded sectional view of the water pump in FIG. In FIG. 9, it is explanatory drawing by the side of the attachment surface of the water pump by a XX arrow. FIG. 9 corresponds to a cross-sectional view taken along the line IX-IX in FIG. FIG. 4 is a perspective view of the water pump attached in the direction of arrow XI in FIG. 3.

A lubricating oil supply structure for an internal combustion engine according to an embodiment of the present invention will be described with reference to FIGS.
In the description of the present specification and the claims, the directions such as front, rear, left, right, up, down, etc., follow the direction of the vehicle when the power unit including the lubricating oil supply structure for the internal combustion engine according to the present embodiment is mounted on the vehicle. Shall. In this embodiment, the vehicle is a small vehicle, and is a scooter type motorcycle.
In the figure, arrow FR indicates the front of the vehicle, LH indicates the left side of the vehicle, RH indicates the right side of the vehicle, and UP indicates the upper side of the vehicle.
Moreover, the black small arrow in a figure shows the flow of lubricating oil typically.

  FIG. 1 shows a power unit 3 having a lubricating oil supply structure for an internal combustion engine according to the present embodiment, mounted on a scooter type motorcycle (hereinafter simply referred to as “motorcycle”) 1.

In the motorcycle 1, a vehicle body front portion 1 </ b> A and a vehicle body rear portion 1 </ b> B are connected via a low floor portion 1 </ b> C, and a vehicle body frame 2 forming a skeleton of the vehicle body is generally composed of a down tube 21 and a main pipe 22.
That is, the down tube 21 extends downward from the head pipe 20 of the vehicle body front portion 1A, the down tube 21 is bent horizontally at the lower end and extends rearward below the floor portion 1C, and is disposed in the vehicle width direction at the rear end. A pair of left and right main pipes 22 are connected via the connecting frame 23. The main pipe 22 rises obliquely rearward from the connection frame 23, and bends so as to loosen the slope in the middle and extends rearward.

The fuel tank 11 and the like are supported by the main pipe 22, and the seat 12 is disposed above the fuel tank 11.
On the other hand, in the front part 1A of the vehicle body, a handle 13 is provided above and supported by the head pipe 20, a front fork 14 extends downward, and a front wheel 15 is supported at the lower end thereof.

A bracket 24 protrudes in the vicinity of the lower end of the inclined portion of the main pipe 22, and the power unit 3 is connected to the bracket 24 via a link member 25 so as to be swingable.
The front of the power unit 3 is a single-cylinder four-stroke water-cooled internal combustion engine (“internal combustion engine” of the present invention; hereinafter simply referred to as “internal combustion engine”) 30. The end of the hanger arm 50 that protrudes forward from the lower end of the power unit case 5 is in a posture in which the cylinder block 31 is tilted largely forward to a substantially horizontal state. A pivot member 26 is connected to a link member 25 attached to the bracket 24 of the main pipe 22.

The power unit 3 is fastened substantially horizontally in front of the power unit case 5 and fastened so that the cylinder block 31, the cylinder head 32, and the cylinder head cover 33 are stacked one after another. A transmission 40 is configured, and a rear wheel 16 is provided on a rear axle 42 that is an output shaft of a speed reduction mechanism 41 provided at a rear portion thereof.
A rear cushion 17 is interposed between a bracket 52 erected at the rear portion of the power unit 3 having the speed reduction mechanism 41 and the rear portion of the main pipe 22.

  As shown in FIG. 2, which is a left side view of the power unit 3, at the upper part of the power unit 3, the intake pipe 60 extends from the upper part of the cylinder head 32 that is largely inclined forward of the internal combustion engine 30, and curves backward. A throttle body 61 connected to 60 is positioned above the cylinder block 31, and an air cleaner device 6 connected to the throttle body 61 via a connecting pipe 62 is disposed above the belt type continuously variable transmission 40. Yes.

The intake pipe 60 is provided with an injector 63 that injects fuel toward the intake port.
On the other hand, the exhaust pipe 65 extending downward from the lower portion of the cylinder head 32 is bent rearward, is biased to the right and extends rearward, and is connected to the muffler 66 on the right side of the rear wheel 16.

The motorcycle 1 includes a vehicle body cover 18, and the vehicle body front portion 1A is covered from the front and the back by a front cover 18a and a leg shield 18b, and the lower portion is covered from the front to the left and right by the front lower cover 18c. Covered by a cover 18d.
The floor portion 1C is covered with a side cover 18e, and the vehicle body rear portion 1B is covered with a body cover 18f from the left and right sides.

In FIGS. 1 and 2, reference numeral 27 denotes a main stand attached to the front lower portion of the power unit case 5 of the power unit 3, and reference numeral 28 denotes a kick starter arm attached substantially to the left of the center of the power unit 3.
A storage box support stay 29 attached to the main frame 22 supports the storage box 19 provided below the seat 12.

FIG. 3 is a developed sectional view of the power unit 3 as viewed in the direction of arrows III-III in FIG.
In the internal combustion engine 30, a connecting rod 35 connects a piston 34 that reciprocates within a cylinder liner 31 a of a cylinder block 31 and a crank pin 51 a of a crankshaft 51.
A combustion chamber 32 a is formed between the top of the piston 34 and the cylinder head 32.

  The power unit case 5 is configured by combining a left power unit case 5L and a right power unit case 5R which are divided into left and right parts. The right power unit case 5R is a right half of a crankcase portion ("crankcase" of the present invention) 5a. The left power unit case 5L has a front half that forms the left half of the crankcase portion 5a, and extends rearward to accommodate a long belt-type continuously variable transmission 40 in the front and rear. Form.

  The front left and right open surface 53L of the left power unit case 5L (transmission case 4) is covered with a transmission case cover 43, the belt type continuously variable transmission 40 is housed therein, and the rear right open surface 53R is Covered by the speed reducer case 44, the speed reduction mechanism 41 is housed inside.

  A crankshaft 51 is oriented in the vehicle width direction and is rotatably supported by the left and right main bearings 54L and 54R in the crankcase portion 5a formed by combining the front portion of the left power unit case 5L and the right power unit case 5R. A cam chain drive sprocket 55, an oil pump drive gear 56, and an AC generator 57 are provided in the right extension portion of the extension portion extending in the horizontal direction, and the belt type continuously variable transmission 40 is provided in the left extension portion. A centrifugal weight 45 and a drive pulley 46 are provided.

  The belt-type continuously variable transmission 40 is configured such that a V-belt 48 is stretched between a driving pulley 46 and a driven pulley 47 provided on an input shaft 41a of a speed reduction mechanism 41 to transmit power. The winding diameter of the V-belt 48 in the driving pulley 46 is changed by the centrifugal weight 45 that moves in accordance with the number, and at the same time, the winding diameter in the driven pulley 47 is automatically changed to change continuously.

The rotation of the driven pulley 47 is transmitted to the input shaft 41 a of the speed reduction mechanism 41 via the centrifugal clutch 49.
The speed reduction mechanism 41 is a gear mechanism, and a gear mesh is formed between the input shaft 41a and the intermediate shaft 41b and between the intermediate shaft 41b and the rear axle 42 to reduce the rotation of the input shaft 41a. This is transmitted to the rear axle 42, and the rear wheel 16 is rotated.

The internal combustion engine 30 of the present embodiment employs an SOHC type valve system, and a valve mechanism 80 is provided in the cylinder head cover 33, and a cam chain 81 that transmits power to the valve mechanism 80 includes a camshaft 82. Between the right power unit case 5R, the cylinder block 31, and the cylinder head 32. The cam chain chamber 83 is provided between the right power unit case 5R, the cylinder block 31, and the cylinder head 32.
That is, the cam chain 81 is located in the cam chain chamber 83 between the driven cam chain sprocket 84 fitted to the right end of the cam shaft 82 oriented in the horizontal direction and the drive cam chain sprocket 55 fitted to the crankshaft 51. Is passed through.

On the other hand, a spark plug 36 is fitted into the cylinder head 32 from the opposite side (left side) of the cam chain chamber 83 toward the combustion chamber 32a.
An intake port (not shown) extends upwardly from the combustion chamber 33a of the cylinder head 33, which is largely inclined forward, and is connected to the intake pipe 60, and an exhaust port (not shown) extends downwardly from the combustion chamber 33a. The exhaust pipe 65 is connected (see FIG. 2).
The intake port communicates with the combustion chamber 33a via an intake valve (not shown), and the exhaust port communicates with the combustion chamber 33a via an exhaust valve (not shown). The intake valve and the exhaust valve are connected to the rotation of the crankshaft 51 by the valve mechanism 80. Opened and closed at a predetermined timing.

The camshaft 82 of the valve mechanism 80 is rotatably supported via bearings 82a and 82a on the left side wall 32b of the cylinder head 32 and the inner side wall 32c constituting the cam chain chamber 83, and protrudes from the right side bearing 82a. A driven cam chain sprocket 84 is fitted to the right end.
The camshaft 82 is rotationally driven by the cam chain 81 at a half rotational speed of the crankshaft 51.

An intake rocker shaft 85i and an exhaust rocker shaft 85e are installed in parallel with the camshaft 82 at diagonally upper and lower positions in front of the camshaft 82, and the intake rocker arm 86i and the exhaust rocker arm 86e are pivotally attached to each other. .
The intake rocker arm 86i swings according to the intake cam 87i of the rotating camshaft 82 to open and close the intake valve, and the exhaust rocker arm 86e swings according to the exhaust cam 87e of the rotating camshaft 82 to open and close the intake valve.

  As shown in FIG. 3, the side wall constituting the cam chain chamber 83 of the right power unit case 5R has a large opening, and the opening is closed by a partition wall 58 attached by a bolt from the right side. The crankshaft 51 passes through 58a.

  In the AC generator 57, a bowl-shaped outer rotor 57b is fixed to the right end portion of the crankshaft 51 passing through the cylindrical portion 58a of the partition wall 58 via an ACG boss 57a, and is disposed on the inner peripheral surface thereof in the circumferential direction. An inner stator 57e around which a stator coil 57d is wound is fixed to the cylindrical portion 58a of the partition wall 58 inside the magnet 57c.

  A fan substrate 59a having a disk shape with the center bulging is attached to the right side surface of the outer rotor 57b, and a plurality of radiator fans 59 are formed on the fan substrate 59a so as to protrude rightward.

The outer periphery of the outer rotor 57b of the AC generator 57 is generally surrounded by a peripheral wall 5Ra extending rightward from the side wall of the right power unit case 5R. The outer periphery of the radiator fan 59 is surrounded by a radiator mounting base 90, and the right side of the radiator fan 59 A radiator 91 is provided adjacent to the radiator 91, and the radiator 91 is covered with a radiator cover 92 with a louver.
The outside air sucked by the radiator fan 59 from the louver of the radiator cover 92 cools the radiator 91 and then is discharged from a vent hole (not shown) provided along the outer periphery of the radiator mounting base 90.

  In the present embodiment, as shown in FIG. 3, the radiator cover 92 is fastened together with the radiator mounting base 90 to the right power unit case 5 </ b> R by a through bolt 93, thereby simplifying the configuration. .

  In FIG. 3, reference numeral 95 denotes a water pump for water cooling of the internal combustion engine, which is attached to the circular opening 32d on the right side surface of the cylinder head 32. The left end of the water pump drive shaft 95a is drilled in the right end surface of the camshaft 82. The fitting hole 82b is inserted and directly connected, and is configured to rotate coaxially.

  On the other hand, as shown in FIG. 4, the lower portion of the crankcase portion 5 a is formed in the oil reservoir 70, and the lubricating oil stored in the oil reservoir 70 is sucked into the oil pump 72 through the oil filter 71, The crankshaft 51 and other parts of the internal combustion engine are pumped.

  The oil pump 72 is provided in the right power unit case 5R, and an oil pump driven gear 73 that meshes with an oil pump drive gear 56 (see FIG. 3) provided in a right extension portion of the crankshaft 51 from the right main bearing 54R. As a result, the oil pump shaft 74 is rotationally driven.

  Lubricating oil discharged from the discharge port 72a of the oil pump 72 is connected to the supply oil passage 75a from the supply oil passage 75a provided forward in the right power unit case 5R and from the right power unit case 5R to the left power unit case 5L. Upper and lower oils connected to the transverse oil passage 75b through the transverse oil passage 75b (see FIGS. 4 and 5) drilled transversely and drilled with the front of the crankshaft 51 facing upward in the left power unit case 5L. It passes through a path 75c (see FIG. 5) and reaches a branching portion 75d above the axis X of the crankshaft 51 of the crankcase portion 5a.

In the branch portion 75d, a front-rear direction oil passage 76 that crosses in the front-rear direction is connected, and a front end 76a thereof opens to a split surface 5b between the crankcase portion 5a and the cylinder block 31, Connecting.
As shown in FIG. 6, the cylinder block oil passage 77 is connected to a stud bolt hole 31b through which a stud bolt for fastening the cylinder block 31 to the crankcase portion 5a is inserted, and the stud stud bolt hole 31b is used as an oil passage. The sent lubricating oil is supplied into the cylinder head 32 and used for lubricating the valve operating mechanism 80 and the like.

As shown in FIGS. 3 and 7, a crankcase for holding a left main bearing (“bearing member” of the present invention) 54L that rotatably supports a left crank journal portion (the “crank journal portion” of the present invention) 51bL. An oil seal 101 is attached to the left crankshaft hole 5La of the left power unit case 5L forming the portion 5a between the crankcase portion 5a and the crankshaft 51 on the left outer side in the axial direction than the left crank journal portion 51bL. An oil chamber 100 is formed between the outer surface of the left main bearing 54L and the oil seal 101.
As shown in FIG. 5, the rear end 76 b of the front-rear direction oil passage 76 communicates with the oil chamber 100 above the axis X of the crankshaft 51 to form an oil chamber inlet 102.

On the other hand, a web outer surface (an “outer surface” of the present invention) 103 of a left crank web (the “crank web” of the present invention) 51 cL connected to the left crank journal portion 51 b L and an annular plate-like shape attached to the web outer surface 103. An oil sump 105 is formed between the side plate 104, and the oil sump 105 communicates with the oil chamber 100 via an oil groove 106 formed in the axial direction on the outer peripheral surface of the left crank journal portion 51bL.
Further, the left crank web 51cL is provided with the left end of the hollow portion 107 of the crank pin 51a opened to the web outer surface 103, and the opening 107a is disposed facing the oil sump 105.

  Accordingly, the oil is supplied from the oil chamber inlet 102 to the lubricating oil by the oil pump 72 driven by the crankshaft 51 via the supply oil passage 75a, the transverse oil passage 75b, the vertical oil passage 75c, and the front-rear oil passage 76. When introduced into 100, the lubricating oil is fed into the oil sump 105 through an oil groove 106 formed in the outer peripheral surface of the left crank journal portion 51bL, and further, a predetermined amount of oil is passed through the hollow portion 107 in the crank pin 51a. Oil is supplied to the lubrication point.

  As shown in FIG. 7, the lubricating oil in the oil sump 105 sent from the oil groove 106 is stored from the outer peripheral side of the oil sump 105 by the centrifugal force generated by the rotation of the crankshaft 51, and is left outside the web of the left crank web 51cL. A drain hole 108 is formed in the side plate 104 for discharging the lubricating oil when the amount of lubricating oil in the oil reservoir 105 exceeds a predetermined level. Has been.

Accordingly, when the pressure of the lubricating oil is increased more than necessary in the oil chamber 100 and the oil reservoir 105, that is, when excessive lubricating oil is supplied, the discharge holes formed in the side plate 104 Lubricating oil can be discharged from 108, and it is possible to prevent the pressure from increasing more than necessary in the oil reservoir 105 and the oil chamber 100 communicating with the oil reservoir 105.
As a result, a simple structure can be achieved without forming a partition or the like for reducing the hydraulic pressure applied to the oil seal 101 on the crankcase portion 5a (left power unit case 5L) side between the oil chamber 100 and the oil seal 101. This makes it difficult for large oil pressure to be applied to the oil seal 101, which can prevent the influence of displacement of the oil seal 101 and a decrease in durability, and increase the degree of freedom in the capacity design of the oil chamber 100. It is possible to do.

As shown in FIG. 7, in the present embodiment, the left main bearing 54L is a seal bearing having a seal member 109 on the outer surface on the oil chamber 100 side, and the side plate 104 is closer to the outer periphery of the left crank web 51cL. The web outer surface 103 is in contact with the inner surface 110 on the oil sump 105 side on the left crank journal portion 51bL side of the left main bearing 54L.
The side plate 104 is fixed to a member that rotates together with the left crank journal portion 51bL without a sliding portion, and forms an oil sump 105.

  Therefore, by using the left main bearing 54L as a seal bearing, an inadvertent flow of lubricating oil between the oil chamber 100 and the oil reservoir 105 is prevented, and the lubricating oil can be efficiently guided from the oil chamber 100 to the oil groove 106. In addition, the lubricating oil can be supplied from the oil groove 106 of the left crank journal portion 51bL to the oil reservoir 105, and the lubricating oil can be held in the oil reservoir 105 efficiently.

  The left main bearing 54L is a seal bearing, and the outer race 54Lo fitted to the crankcase portion 5a, the inner race 54Li fitted to the left crank journal portion 51bL, the inner circumference of the outer race 54Lo, and the inner race 54Li. And the discharge hole 108 is provided between the inner periphery of the outer race 54Lo and the outer periphery of the inner race 54Li.

  Therefore, the lubricating oil discharged from the discharge hole 108 is discharged to the gap portion 111 between the inner circumference of the outer race 54Lo and the outer circumference of the inner race 54Li, that is, the accommodation portion of the ball member 54Lb. Lubricating oil is easily discharged. A part of the lubricating oil discharged from the discharge hole 108 can also function as the lubricating oil for the left main bearing 54L.

  Further, the left crank journal portion 51bL has a larger diameter than the journal outer shaft portion 51dL extending outward from the left crank journal portion 51bL. Therefore, an oil chamber is provided between the left crank journal portion 51bL and the journal outer shaft portion 51dL. An annular step 112 facing 100 is formed. A pair of the oil grooves 106 reaching the root of the left crank journal portion 51bL from the annular step portion 112 is provided on the outer peripheral surface of the left crank journal portion 51bL. The oil groove 106 has an opening 106a at the opening end to the step portion 112. It becomes.

  The oil groove 106 and the side plate 104 will be described further. As shown in FIG. 7, the oil groove 106 is formed in a cylindrical shape having an axis parallel to the axis X of the crankshaft 51 (in an arc shape in the axial section). The crank journal 51bL has a circumferential surface notched or formed when the crankshaft 51 is forged. The center of rotation of the left crank journal 51bL is approximately 90 ° out of phase with the crankpin 51a to facilitate its formation. It is arranged in two places.

  On the other hand, in the crankshaft 51, a circular concave portion 103a is formed on the web outer surface 103 of the left crank web 51cL on the same side as the left crank journal portion 51bL. The concave portion 103a surrounds the left crank journal portion 51bL. An annular side plate 104 is press-fitted, and an annular and flat oil sump 105 is defined between the side plate 104 and the left crank web 51cL, and an outlet 106b of the oil groove 106 is opened radially inside the oil sump 105. Then, the hollow portion 107 of the crank pin 51a is opened in the middle portion.

Since the inner race 54Li of the left main bearing 54L is fitted to the left crank journal portion 51bL, the bottom of the oil groove 106 (axis X side of the crankshaft 51) 106c and the inner peripheral surface 113 of the inner race 54Li Between these, a substantial groove oil passage 114 is formed.
Since the side plate 104 abuts on the outlet 106b side of the oil groove 106, a region where the inner circumferential circular hole 104a of the side plate 104 overlaps the oil groove 106 cross section is a substantial oil reservoir inlet 105a.

  Further, the outer peripheral surface of the left crank journal portion 51bL substantially corresponds to the cross-sectional position of the crank pin 51a from the inner side surface (pouring side surface) 110 of the inner race 54Li of the left main bearing 54L to the root of the left crank journal portion 51bL. A cylindrical surface having an axis parallel to the axis X of the crankshaft 51 is cut out in a cylindrical shape (in an arc shape in the axial section), or a notch 115 formed when the crankshaft 51 is forged is provided. Thus, a smooth flow of the lubricating oil from the oil reservoir 105 to the opening 107a of the hollow portion 107 of the crank pin 51a is achieved.

  Accordingly, the discharge hole 108 for discharging the excess lubricating oil from the oil reservoir 105 is provided facing the gap portion 111 between the inner periphery of the outer race 54Lo and the outer periphery of the inner race 54Li. Is provided closer to the axis X side of the crankshaft than the axis Y of the hollow portion 107 of the crankpin 51a, the lubricating oil that has entered the sump 105 from the oil sump inlet 105a through the oil groove 106 is The centrifugal force generated by the rotation of the crankshaft 51 promptly flows to the outer peripheral side of the oil sump 105 and is prevented from entering the discharge hole 108 and stored, and preferentially enters the hollow portion 107 of the crankpin 51a from the opening 107a. Supplied.

  That is, in the oil reservoir 105, the lubricating oil is accumulated from the side far from the axis X of the crankshaft 51 by centrifugal force, but the discharge hole 108 is more crankshaft than the axis Y of the hollow portion 107 of the crankpin 51a. 51 is provided on the side of the shaft center X, so that it becomes possible to hold a sufficient amount of lubricating oil in the hollow portion 107 in preference to the discharge of the lubricating oil from the discharge hole 108. It is also possible to efficiently refuel.

Further, in the present invention, even one discharge hole 108 can be implemented. However, in this embodiment, as shown in FIG. 7, two discharge holes 108 are provided (two or more numbers are acceptable), 1 Another discharge hole 108 is provided with a positional relationship of 180 ° with respect to one discharge hole 108.
Therefore, it is possible to further improve the establishment of lubricating oil discharge with respect to the rotation of the crankshaft 51, and when unnecessary pressure increases in the oil reservoir 105 and the oil chamber 100 communicating with the oil reservoir 105, unnecessary lubrication is quickly performed. Oil can be drained.

Further, the discharge hole 108 is provided at a position where the gap 107A between the opening 107a of the crank pin 51a and the oil groove 106A that is first adjacent to the opening 107a on the rotation direction R side of the crank pin 51 is removed. .
That is, the discharge hole in the lubricating oil path S from the oil groove 106A that is first adjacent to the opening 107a on the rotation direction R side of the crankshaft 51 to the opening 107a of the crankpin 51a that is relatively in the counter-rotation direction. By preventing 108 from being exposed, inadvertent discharge of the lubricating oil flowing from the oil groove 106 into the oil sump 105 can be prevented, and the lubricating oil can be efficiently supplied from the oil groove 106 to the hollow portion 107 of the crank pin 51a. Can be led.

  As clearly shown in FIG. 5, the oil chamber inlet 102 through which the lubricating oil supplied by the oil pump 72 is guided to the oil chamber 100 is provided above the axis X of the crankshaft 51. The lubricating oil can be easily filled in the oil chamber 100, and a sufficient amount of oil can be stored in the oil chamber 100.

Note that the water pump 95 according to the present embodiment is characterized in its mounting method.
As shown in FIGS. 3 and 9, a circular opening 32d is formed on the right side surface of the cylinder head 32, and a water pump body 96 having a cylindrical shape of the water pump 95 is fitted into the circular opening 32d.
The water pump body 96 of the water pump 95 rotatably supports a water pump drive shaft 95a via a bearing 95b, a cylindrical portion 96a fitted in the circular opening 32d of the cylinder head 32, and an outward opening end. And an enlarged portion 96b that partially accommodates an impeller 95c fitted to the water pump drive shaft 95a. The water pump drive shaft 95a is coaxially coupled to the camshaft 82 and driven. .
A water pump cover 97 that covers the right opening of the enlarged portion 96b of the water pump body 96 and accommodates the impeller 95c together with the enlarged portion 96b is superimposed on the opening end surface of the enlarged portion 96b.

As shown in FIG. 8, on the right side surface of the cylinder head 32, in addition to the circular opening 32d into which the cylindrical portion 96a of the water pump body 96 is fitted, the intake rocker shaft to be inserted when the intake rocker shaft 85i is attached. An intake rocker shaft insertion hole 32e that is inserted when the insertion hole 32i and the exhaust rocker shaft 85e are attached is formed, and a water pump joint surface 32f that connects them together is formed.
In addition, an upper boss 32m (shown on the left side) provided with a female screw for fastening the water pump 95 so as to surround the water pump joint surface 32f and protrude from the right side surface of the cylinder head 32 away from the water pump joint surface 32f. ), A lower boss 32n (right side in the figure), and a rear boss 32o (lower side in the figure).

As shown in FIG. 10, on the mounting surface side of the water pump 95, a mounting surface 96f is formed on the enlarged portion 96b of the water pump body 96 so as to correspond to the water pump joint surface 32f of the cylinder head 32. A seal member groove 99 is provided along the outer edge, and a seal member 99a is mounted. As shown in FIG. 9, the seal member 99 a has a T shape in cross section, and its convex portion is fitted into the seal member groove 99, and the flat plate portion is pressed against the water pump joint surface 32 f of the cylinder head 32. Therefore, preferable mounting properties and sealing properties can be obtained.
When the water pump 95 is attached, as shown in FIG. 9, the seal member 99a is pressed against the water pump joint surface 32f, the circular opening 32d of the cylinder head 31, the intake rocker shaft insertion hole 32i, and the exhaust The rocker shaft insertion hole 32e is closed by the attachment surface 96f of the water pump body 96 inside the annular seal member 99a.

The enlarged portion 96b of the water pump body 96 and the water pump cover 97 are fastened to each other, and a fastening hole for attachment to the cylinder head 32 is provided so as to surround the attachment surface 96f.
That is, the enlarged portion 96b and the water pump cover 97 have upper fastening holes 96m and 97m corresponding to the upper boss 32m of the cylinder head 32, and lower fastening holes 96n and 97n corresponding to the lower boss 32n, respectively. Corresponding to 32o, rear fastening holes 96o, 97o are provided.

  Thus, as shown in FIG. 11, the upper fastening holes 96m and 97m are fastened to the upper boss 32m by the upper mounting bolt 98m, and the lower fastening holes 96n and 97n are fastened to the lower boss 32n by the lower mounting bolt 98n. The rear fastening holes 96o, 97o are fastened together with the rear boss 32o by the rear mounting bolts 98o, and the water pump 95 is attached to the cylinder head 31.

  Here, as shown in FIGS. 9 and 10, the enlarged portion 96b of the water pump body 96 and the water pump cover 97 are provided with front fastening holes 96p and 97p at the front (upper side in the drawing). The water pump 95 is assembled in a well-balanced position in the up / down and front / rear positions by the part fastening bolts 98p. The front part fastening bolts 98p are connected to the cylinder head 31 or cylinder corresponding to the positions as shown in FIGS. It does not extend to the head cover 32 and is used only for pump assembly. Accordingly, the formation of the fastening boss portion protruding forward in the cylinder head 31 is omitted, and the structure is simplified.

According to the mounting method of the water pump 95 of the present embodiment, the right side wall of the cylinder head 32 and the water pump 95 include the circular opening 32d and the cylindrical portion 96a, the water pump joint surface 32f, and the mounting surface 120 of the enlarged portion 96b. Are joined via the seal member 122, and the bosses 32m, 32n, 32o for attachment on the cylinder head 32 side protrude from the right side surface of the cylinder head 32, and the contact surfaces of both are limited.
Therefore, the transfer of heat from the cylinder head 32 to the water pump 95 for cooling water can be suppressed.
Further, the circular seal member 99a can collectively seal and shield the circular opening 32d of the cylinder head 31, the intake rocker shaft insertion hole 32i, and the exhaust rocker shaft insertion hole 32e. Work is also easy.

Although one embodiment of the present invention has been described above, the aspect of the present invention is not limited to the above-described embodiment, and it is needless to say that the present invention includes those implemented in various aspects within the scope of the gist of the present invention.
For example, the number of discharge holes 108 and oil grooves 106 is not limited to this embodiment, and may be one.
However, if the two discharge holes 108 are provided as a pair as in the above embodiment, a more preferable effect as described above can be obtained.

  DESCRIPTION OF SYMBOLS 1 ... Motorcycle (scooter type motorcycle), 3 ... Power unit, 5 ... Power unit case, 5a ... Crankcase part ("crankcase" of this invention), 5L ... Left power unit case, 5La ... Left crankshaft hole, 5R ... Right power unit case, 30 ... Internal combustion engine (water-cooled internal combustion engine), 31 ... Cylinder block, 31b ... Stud bolt hole, 32 ... Cylinder head, 33 ... Cylinder head cover, 51 ... Crank shaft, 51a ... Crank pin, 51bL ... Left crank Journal part ("crank journal part" of the present invention), 51cL ... left crank web ("crank web" of the present invention), 51dL ... journal outer shaft part, 54L ... left main bearing ("bearing member" of the present invention) , 54Lb ... ball member, 54Li ... inner race, 54Lo ... outer race, 56 ... oil pump drive gear, 70 ... oil sump 72 ... Oil pump, 72a ... Discharge port, 73 ... Oil pump driven gear, 100 ... Oil chamber, 101 ... Oil seal, 102 ... Oil chamber inlet, 103 ... Web outer surface ("outer surface" of the present invention), 104 ... Side plate, 105 ... Oil sump, 106, 106A ... Oil groove, 107 ... Hollow part, 107a ... Opening, 108 ... Discharge hole, 109 ... Seal member, 111 ... Gap portion, X ... Axis of crankshaft 51, Y ... Axial center of hollow portion 107, R ... rotational direction of crankshaft 51, S ... lubricating oil path

Claims (7)

A crank journal (51bL) of the crankshaft (51) of the internal combustion engine (30) is rotatably supported on the crankcase (5a) via a bearing member (54L).
An oil seal (101) is mounted between the crankcase (5a) and the crankshaft (51) on the outer side in the axial direction than the crank journal portion (51bL),
An oil chamber (100) is formed between the outer surface of the bearing member (54L) and the oil seal (101),
An oil sump (105) is formed between the outer surface (103) of the crank web (51cL) connected to the crank journal portion (51bL) and the side plate (104) attached to the outer surface (103), The oil sump (105) communicates with the oil chamber (100) via an oil groove (106) formed on the outer peripheral surface of the crank journal part (51bL),
Lubricating oil is introduced into the oil chamber (100) by an oil pump (72) driven by the crankshaft (51), and the hollow portion (107 in the crankpin (51a) from the oil reservoir (105). ) In the lubricating oil supply structure of the internal combustion engine to be supplied to a predetermined lubricating location,
The side plate (104) is formed with a discharge hole (108) for discharging the lubricating oil when the amount of lubricating oil in the oil reservoir (105) exceeds a predetermined value. Lubricating oil supply structure for internal combustion engines.   The bearing member (54L) is a seal bearing having a seal member (109) on the outer surface on the oil chamber (100) side, and the side plate (104) is located outside the outer periphery of the crank web (51cL). The internal combustion engine according to claim 1, wherein the side surface (103) is in contact with a side surface of the bearing member (54L) on the side of the oil reservoir (105) on the crank journal portion (51bL) side. Oil supply structure.   The crank web (51cL) is provided with the crank pin (51a) having the hollow portion (107) opened at one end, and the opening (107a) is disposed facing the oil reservoir (105). The internal combustion engine according to claim 2, wherein the discharge hole (108) is provided closer to the axial center (X) of the crankshaft (51) than the axial center (Y) of the hollow portion (107). Engine oil supply structure.   The seal bearing (54L) includes an outer race (54Lo) fitted to the crankcase (5a), an inner race (54Li) fitted to the crank journal portion (51bL), and the outer race (54Lo). An inner periphery and a ball member (54Lb) held on the outer periphery of the inner race (54Li), and the discharge hole (108) includes an inner periphery of the outer race (54Lo), an outer periphery of the inner race (54Li), 4. The lubricating oil supply structure for an internal combustion engine according to claim 2, wherein the lubricating oil supply structure is provided so as to face each other.   At least two discharge holes (108) are provided, and another discharge hole (108) is provided in a positional relationship that is 180 degrees out of phase with respect to one discharge hole (108). The lubricating oil supply structure for an internal combustion engine according to any one of claims 2 to 4.   The crank web (51cL) is provided with a crank pin (51a) having the hollow portion (107) opened at one end, and the opening (107a) is disposed facing the oil sump (105), The discharge hole (108) includes the opening (107a) of the crank pin (51a) and the oil that is first adjacent to the opening (107a) on the rotation direction (R) side of the crankshaft (51). The lubricating oil supply structure for an internal combustion engine according to any one of claims 2 to 5, wherein the lubricating oil supply structure is provided at a position away from the groove (106A).   An oil chamber inlet (102) through which the lubricating oil supplied by the oil pump (72) is guided to the oil chamber (100) is provided above the axis (X) of the crankshaft (51). The lubricating oil supply structure for an internal combustion engine according to any one of claims 1 to 6.

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