JP2002129927A - Breather structure of four-cycle engine lubricating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a breather structure preventing oil mist and oil from bleeding from a breather chamber in four-cycle engine lubricating device circulating the oil mist. SOLUTION: In the breather structure of a four-cycle engine lubricating device wherein oil mist is generated by spraying oil from an oil pan 2 to an crankshaft, the oil mist is circulated through a valve mechanism chamber 9 by pressure pulsation of a crank chamber 1 as well as a part of the oil mist is separated to gas and liquid through a breather chamber 12 to return the oil into an oil pan 2, an oil returning passage 19 is connected with the bottom of the breather chamber 12 and the oil is directly returned from the breather chamber 12 to the oil pan 2 via the oil returning passage 19.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a four-stroke engine lubrication system using oil mist, and more particularly to a breather structure communicating with the lubrication system.

[0002]

2. Description of the Related Art As a lubricating device for a small four-stroke engine, an oil reservoir is provided in an engine main body, and an oil slinger for generating oil mist by scattering lubricating oil stored in the oil reservoir is connected to a crankshaft or a crankshaft. A lubricating device provided on a rotating shaft for circulating the oil mist is disclosed in Japanese Patent Application Laid-Open No. 9-170417. Japanese Patent Application Laid-Open No. H10-115208 discloses a lubricating oil mist generator that improves the slinger for generating the oil mist and scatters the lubricating oil in the oil reservoir by a slinger having a simple structure.

[0003] However, in the structure of the lubricating device described in each of the above publications, a dedicated slinger for generating oil mist is provided on the crankshaft or the rotating shaft interlocking with the crankshaft. There was a problem that it would. In order to reliably supply oil and oil mist to various parts of the engine, particularly to the valve operating chamber, an oil passage having a sufficiently large sectional area for the oil mist is formed in consideration of the sectional area and path of the oil passage. It is necessary and there is a great restriction on the design.

In view of such prior art, the applicant of the present application has disclosed in the prior application (Japanese Patent Application No. 11-192984) that the oil mist is surely generated without increasing the size of the engine, and the oil is supplied to various parts of the engine. A lubrication method and a lubrication structure for a four-stroke engine that can reliably supply the lubricating oil to the engine are proposed.

The proposed lubricating device injects oil from an oil pan to a crankshaft to generate oil mist, which is returned to the oil pan via a check valve by a pressure pulsation of a crank chamber, and then returned to the oil pan. In this configuration, the oil is introduced into the valve operating chamber through the oil mist passage, returned from the valve operating chamber to the crank chamber via a check valve, and circulated. The oil mist passage branches on the way and communicates with the breather chamber, where gas and liquid are separated, air is introduced into the air cleaner through the breather pipe, liquid oil is introduced into the lower part of the valve operating chamber, and the crank chamber is introduced from the bottom of the valve operating chamber. To the oil pan from the crankcase.

[0006]

However, in the lubricating device proposed by the applicant of the present invention, the oil mist generation method and the structure thereof have been greatly improved as compared with the conventional one, but the associated breather structure has been described. With regard to the above, a large amount of separated oil may flow out of the breather pipe to the air cleaner side. It is considered that this is because the oil mist circulation action of the lubricating device is increased by the structure improved from the prior art, the amount of oil separated in the breather chamber is increased, and the return is insufficient.

In view of the foregoing, an object of the present invention is to provide a breather structure that prevents oil mist and oil from flowing out of a breather chamber in a four-cycle engine lubrication system that circulates oil mist.

[0008]

In order to achieve the above object, according to the present invention, oil mist is generated by injecting oil from an oil pan onto a crankshaft, and the oil mist is actuated by pressure pulsation in a crank chamber. A breather structure of a four-stroke engine lubricating device that circulates a part of the oil mist through a breather chamber and returns oil to the oil pan while circulating through the chamber, and connects an oil return passage to the bottom of the breather chamber. Further, there is provided a breather structure of a four-stroke engine lubricating apparatus, wherein oil from a breather chamber is directly returned to an oil pan through the oil return passage.

According to this configuration, the oil separated in the breather chamber is directly returned to the oil pan from the oil return passage at the bottom of the breather chamber without passing through the crank chamber, so that a large amount of oil flows smoothly to the oil pan. Can escape from the breather chamber and out of the breather pipe. In this case, the configuration is simplified by circulating the oil mist while reciprocating in a pulsating cycle by the pressure pulsation of the crank chamber without using the check valve, thereby simplifying the configuration and preventing the oil mist circulation amount from becoming excessively large and ensuring proper oil mist circulation. The oil from the breather chamber is reliably returned to the oil pan as the circulation amount.

In a preferred embodiment, the oil return passage is opened at a position below the oil level of the oil pan.

According to this configuration, since the oil return passage communicating with the breather chamber is opened below the oil level of the oil pan, the influence of the pulsation from the crank chamber into the breather chamber is almost eliminated, and the oil is smoothly removed from the oil pan. Return to bread.

In a further preferred embodiment, the lubricating device is configured to inject oil from an oil pan together with a crankshaft to a camshaft in the valve operating chamber and directly return the oil from the bottom of the valve operating chamber to the oil pan. Further, the oil mist is branched from the oil pan and passes through the oil pump drive gear chamber to the valve operating chamber upper side and the breather chamber side.

According to this configuration, the oil mist generated in the crank chamber is introduced into the valve operating chamber, and at the same time, the oil from the oil pan is injected to the camshaft, so that the lubricating effect is enhanced. Further, the oil in the valve chamber is directly returned to the oil pan from the bottom thereof, so that the oil circulates smoothly and a highly reliable lubrication function is obtained. Further, since the oil mist of the oil pan is configured to pass through the oil pump drive gear chamber close to the oil pan and then branch and flow to the breather chamber, the breather chamber can be disposed compactly in the engine.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a lubrication device according to an embodiment of the present invention. An oil pan 2 is provided in communication with the crank chamber 1, and oil 70 is stored therein. 70a indicates an oil level. The crank chamber 1 accommodates a crankshaft, a connecting rod, a piston, and the like (both not shown) interlocked with the crankshaft. The crankshaft in the crank chamber 1 drives an oil pump (trochoid pump) 4 via a driving gear in an oil pump driving gear chamber 3. The oil pump 4 sucks the oil in the oil pan 2 through the strainer 5 and pumps the oil into the crank chamber 1 through the oil passage 6.

The oil passage 6 has a jet port (jet) 7 facing the crank chamber 1 and injects the oil fed under pressure toward the crank chamber. As a result, the liquid oil collides with a rotating part such as a web or a connecting rod of the crankshaft and is scattered, agitated and atomized to generate an oil mist.

The crank chamber 1 communicates with an oil pan 2 through a communication hole (not shown) at the bottom thereof, and oil mist generated in the crank chamber 1 flows into the oil pan 2 together with liquid oil. In this case, the oil mist and oil from the crank chamber 1 to the oil pan 2
A deflector (not shown) for preventing oil agitation in the oil pan may be provided.

The oil passage 6 is connected to a valve operating chamber 9 for accommodating a valve operating system for driving an intake valve and an exhaust valve (neither is shown) continuously from a branch portion of the jet 7 communicating with the crank chamber 1. Communicate. The oil passage 6 communicating with the valve operating chamber 9 has an ejection port (jet) 8 at a position facing the valve operating chamber 9 and facing the camshaft 10. Inject.

The oil mist filled in the oil pan 2 flows through the oil pump drive gear chamber 3 and flows into the oil mist chamber 11, where it is divided into two directions, one of which flows toward the breather chamber 12; The other is supplied through an oil mist passage 15 to a rocker arm (not shown) in the valve operating chamber upper part 16 and the like. In the breather chamber 12, the liquid component (oil) of the oil mist extruded from the crank chamber is separated from the gas component (air) by a labyrinth structure, for example.
Only air is sent to the air cleaner 13 as breather air. The air cleaner 13 supplies the breather air to the intake system through the element together with the outside air.

On the other hand, the liquid oil separated in the breather chamber 12 is directly returned into the oil pan 2 through an oil return passage 19 connected to the bottom of the breather chamber. The oil return passage 19 is opened near the bottom of the oil pan so that the opening end is lower than the oil level 70a, and returns the oil below the oil level of the oil pan. Accordingly, oil can be returned from the breather chamber 12 to the oil pan 2 stably without being affected by pressure pulsation of the crank chamber 1 or the like.

On the other hand, the oil mist supplied from the oil mist chamber 11 to the upper part 16 of the valve operating chamber 9 through the oil mist passage 15 flows down in the valve operating chamber 9 to lubricate the valve operating system. The oil in the valve train 9 is returned to the oil pan 2 via an oil return hole or oil return passage 71 (not shown) provided at the bottom. In this case, the oil return passage 71 is connected to the oil return passage 19 from the breather chamber 12 described above.
It may be opened below the oil level in the same manner as described above.

In the lubricating device having the above structure, the oil mist generated in the crank chamber 1 circulates in the engine as described above while reciprocating in a pulsation cycle due to the pressure pulsation of the crank chamber accompanying the reciprocating operation of the piston. .

FIGS. 2 to 5 show specific examples of the structure of a four-stroke engine provided with the lubricating device shown in FIG. 2 is a longitudinal sectional view of the engine along the front-rear direction, FIG. 3 is a longitudinal sectional view of the engine along the left-right direction, FIG. 4 is a configuration diagram of the valve chamber seen from the AA direction in FIG. 2, and FIG. FIG. 2 is a configuration diagram of an oil pump portion viewed from the BB direction of FIG.

The engine 20 is an OHV type four-cycle single cylinder engine, and is mounted on a small motorcycle with an engine such as a small motorcycle such as a scooter or a power assisted bicycle.

The crankshaft 21 of the engine 20 is disposed in the front-rear direction of the vehicle body. As shown in FIG. 3, a connecting rod 24 is connected to the web 22 via a connecting pin 23 at a position facing the web 22 in the crank chamber 1. Is done.
A piston 25 is connected to the upper end of the connecting rod 24,
It slides in the cylinder bore 26. An intake valve 28 and an exhaust valve 29 facing a combustion chamber 27 formed on the piston upper surface side.
Is attached.

As shown in FIG. 2, an air cooling fan 30 is fixed to the front end of the crankshaft 21, and cools the engine 20 by introducing outside air from an outside air intake port 32 provided on the front surface of an air shroud 31. . A flywheel magnet 33 is fixed to the crankshaft 21 inside the air cooling fan 30, and forms a generator together with the stator coil 34.

As shown in FIG. 4, a cam drive gear 35 is mounted on the rear end of the crankshaft 21 projecting into the valve operating chamber 9 outside the crank chamber 1. A single camshaft 10 common to the intake and exhaust valves is provided above the crankshaft 21 in the valve chamber 9 in parallel with the crankshaft 21. A cam gear 36 and a cam 37 that mesh with a cam drive gear 35 on the crankshaft side are mounted on the camshaft 10. On the cam 37, cam followers 38 and 39 for intake and exhaust are pivotally mounted on a shaft 40.
Each of the cam followers 38 and 39 slides on the cam 37 to move the push rods 41 and 42 up and down, respectively, and the intake rocker arm 4 attached to the upper ends of these push rods.
3 and the intake valve 28 via the exhaust rocker arm 44.
And the exhaust valve 29 is opened and closed in synchronization with the crankshaft 21.

The valve chamber 9 in the present invention includes a valve chamber upper portion 16 (FIGS. 1 and 4) provided with a rocker arm and an intake / exhaust valve connected to the upper end of the push rod, a cam, a cam follower, and the like. And a lower portion 14 of a valve operating chamber provided with a cam drive gear mounted on a crankshaft.

An intake port 46 is formed in the cylinder head 45 between the push rods 41 and 42, and the intake valve 28 is attached to an end of the cylinder head 45 on the combustion chamber side. An exhaust port 47 is formed toward the front of the cylinder head 45, and the exhaust valve 29 is attached to an end of the exhaust port 47 on the combustion chamber side.

The upper part 16 of the valve operating chamber 9 forming the upper part of the cylinder head 45 accommodating the rocker arms 43, 44 and the like.
Is covered with a head cover 48. An oil mist passage 49 is provided on the upper surface side of the head cover 48. The oil mist passage 49 has an opening 5 facing the upper part 16 of the valve operating chamber 9.
The oil mist is supplied to the upper part 16 of the valve chamber 9 through the opening 50.

As shown in FIG. 3, the engine 20 comprises upper and lower crankcases 51 and 52, and the lower crankcase 52 is joined to the upper crankcase 51 at the mating surface P and fixed with bolts 53. . Thereby, a crank chamber 1 is formed between the two crankcases, and an oil pan 2 is formed below the crankcase 1.

A communication hole 72 is formed at the bottom of the crank chamber 1, and a deflector 73 is provided below the communication hole 72. Oil mist and oil generated in the crank chamber 1 flow through the communication hole 72 and flow into the oil pan 2 via the deflector 73.

As shown in FIG. 5, an oil pump 4 connected to a strainer 5 is provided at the bottom of the oil pan 2. An oil pump drive gear chamber 3 is provided outside the crank chamber 1.
The drive worm gear 55 is mounted on the crankshaft 21 projecting into the oil pump drive gear chamber 3. A worm wheel gear meshing with the drive worm gear 55 is fixed to a drive shaft 57 of the oil pump 4,
The oil pump 4 is driven to rotate. The discharge side of the oil pump 4 is connected to an oil passage rising portion 6a, and pumps oil as shown by an arrow.

The oil passage rising portion 6a is connected to an oil passage horizontal portion 6b parallel to the crankshaft 21. The oil passage horizontal portion 6b is formed with a branch portion 6c substantially at the center of the crankshaft 21, and opens therefrom through the throttle jet 7 to the crank chamber 1 as shown in FIG. Further, the oil passage horizontal portion 6b on the rear side of the crankshaft 21 ahead of the branch portion 6c is connected to the oil passage vertical portion 6d (FIG. 4). This oil passage vertical portion 6d is shown in FIG.
As shown in (1), a bolt hole through which a bolt 53 connecting the upper and lower crankcases 51 and 52 is inserted can be used. The oil passage vertical portion 6 d (bolt hole) opens through the throttle jet 8 toward a position near the cam shaft 10 in the valve chamber 9.

The oil pan 2 has an upper opening 2a (FIG. 5).
The oil pump drive gear chamber 3 communicates with the oil mist chamber 11 through the upper opening 3a. This oil mist chamber 11
Communicates in two directions, one communicates with the oil mist passage 15 via the outlet 11a, and the other communicates with the breather chamber 12
Communicate with The oil mist passage 15 rises along the side of the cylinder as shown in FIG.
Communicates with an oil mist passage 49 formed on the upper surface of the oil mist.

In the breather chamber 12, as shown in FIG.
An opposing comb tooth-shaped labyrinth wall 12a is provided to separate oil mist into gas (air) and liquid oil. The gas from which the oil has been removed is used as breather air for breather pipe 5
8 to an air cleaner (not shown).

On the other hand, the separated liquid oil flows into the oil return passage 19 through, for example, two oil holes 59 provided at the bottom of the breather chamber 12 and returns to the bottom of the oil pan 2. The oil return passage 19 opens below the oil level 70a. The cylinder axis of the engine 20 is inclined by an angle θ with respect to the horizontal.

The lower part 14 of the valve chamber 9 communicates with the oil pan 2 through an oil return hole 75 formed at the bottom as shown in FIG.

In the engine provided with the lubricating device having the above-described structure, the oil in the oil pan 2 is pumped by the oil pump 4 through the oil passage rising portion 6a and the horizontal portion 6b. This oil is injected into the crank chamber 1 through the throttle jet 7. As a result, the liquid oil is poured into the crankshaft 21 to provide a lubricating effect to the web rotating part, the bearing part, the connecting pin 23 and the like, and the injected oil is used to rotate the web 22 and the connecting rod The oil mist is formed by colliding with 24 or the like to generate oil mist.

The oil mist generated in the crank chamber 1 is sent out into the oil pan 2 through the deflector 73 by pressure pulsation caused by the piston operation. The oil mist is further moved from the oil pan 2 to the upper opening 2a.
(FIG. 5) is fed into the oil pump driving gear chamber 3 through the oil pump driving gear chamber 3 to provide a lubricating action to the driving wheel 55 for driving the oil pump, the worm gear 56 and the like.

The oil mist is sent from the oil pump drive gear chamber 3 to the oil mist chamber 11 through its upper opening 3a (FIG. 5), and a part of the oil mist passes through the oil mist passage 15 through the outlet 11a and passes through the head cover. 48 through the oil mist passage 49 at the top, and from the opening 50 to the valve chamber 9
Is supplied to the upper part 16 of the valve operating chamber and lubricates the valve operating system in the valve operating chamber 9.

In the valve operating chamber 9, liquid oil pumped from the oil pump 4 is further filled with the oil passage horizontal portion 6.
b, flows through the vertical portion 6d (bolt hole) of the oil passage ahead of the throttle jet 7 branching to the crank chamber 1, and is injected from the throttle jet 8 toward the camshaft 10, and the cam gear 3
A lubricating action is applied to cam mechanisms such as the cam 6 and the cam 37.

On the other hand, oil mist other than the oil mist sent to the valve train is supplied from the oil mist chamber 11 to the breather chamber 12. Oil mist is in this breather chamber 1
The air from which the liquid-oil component has been removed by the gas-liquid separation in 2 is sent to the air cleaner through the breather pipe 58,
The liquid oil is returned below the oil level of the oil pan 2 through the oil hole 59 and the oil return passage 19.

[0043]

As described above, in the present invention, the oil separated in the breather chamber is directly returned from the oil return passage at the bottom of the breather chamber to the oil pan without passing through the crank chamber, so that a large amount of oil is provided. Can smoothly flow into the oil pan and does not overflow from the breather chamber and flow out of the breather pipe. In this case, the configuration is simplified by circulating the oil mist while reciprocating in a pulsating cycle by the pressure pulsation of the crank chamber without using the check valve, thereby simplifying the configuration and preventing the oil mist circulation amount from becoming excessively large and ensuring proper oil mist circulation. The oil from the breather chamber is reliably returned to the oil pan as the circulation amount.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a lubrication device according to the present invention.

FIG. 2 is a longitudinal sectional view of the lubricating device according to the embodiment of the present invention, taken along the front-rear direction.

FIG. 3 is a longitudinal sectional view of the lubricating device of FIG. 2 along a left-right direction.

FIG. 4 is a view taken in the direction of arrows AA in FIG. 2;

FIG. 5 is a view taken in the direction of arrows BB in FIG. 2;

[Explanation of symbols]

1: crank chamber, 2: oil pan, 3: oil pump drive gear chamber, 4: oil pump, 5: strainer, 7,
8: throttle jet, 9: valve operating chamber, 10: camshaft, 11:
Oil mist chamber, 12: Breather chamber, 14: Lower valve chamber, 15: Oil mist passage, 16: Upper valve chamber, 1
9: oil return passage, 20: engine, 21: crankshaft, 22: web, 23: connecting pin, 24:
Connecting rod, 25: piston, 26: cylinder bore, 2
7: combustion chamber, 28: intake valve, 29: exhaust valve, 30: air cooling fan, 31: air shroud, 32: outside air intake, 33: flywheel magnet, 34: stator coil, 35: cam drive gear, 36 : Cam gear, 37: cam, 38, 39: cam follower, 40: shaft, 41, 4
2: push rod, 43, 44: rocker arm, 4
5: cylinder head, 46: intake port, 47: exhaust port, 48: head cover, 49: oil mist passage,
50: Opening, 51: Upper crankcase, 52: Lower crankcase, 53: Bolt, 55: Drive worm gear, 5
6: worm wheel gear, 57: drive shaft, 58: breather pipe, 59: oil hole, 70: oil, 70a: oil surface, 71: oil return passage, 72: communication hole, 73: deflector, 75: oil return hole .

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yoshiharu Yokoyama 2500 Shinkai, Iwata-shi, Shizuoka Yamaha Motor Co., Ltd. F-term (reference) 3G013 AA05 AB02 BA02 BA04 BB04 BB17 BC01 BC11 BD22 BD23 BD47 3G015 AA05 AB02 BA03 BD11 BD24 BE05 BE15 BF05 BF08 CA06 CA11 DA02 DA10 EA07

Claims (3)

[Claims] 1. An oil mist is generated by injecting oil from an oil pan to a crankshaft, the oil mist is circulated through a valve operating chamber by pressure pulsation of a crank chamber, and a part of the oil mist is removed from a breather chamber. A breather structure of a four-stroke engine lubricating device that separates gas and liquid through the oil pan and returns the oil to the oil pan, wherein an oil return passage is connected to the bottom of the breather chamber, and oil from the breather chamber is passed through the oil return passage. A breather structure for a four-stroke engine lubrication system, which is directly returned to an oil pan. 2. The oil return passage according to claim 1, wherein the oil return passage opens at a position below the oil level of the oil pan.
The breather structure of the four-stroke engine lubrication device according to the above item. 3. The lubricating device is configured to inject oil from an oil pan together with a crankshaft to a camshaft in the valve operating chamber and directly return the oil from the bottom of the valve operating chamber to the oil pan. 3. The four-stroke engine lubricating apparatus according to claim 1, wherein the mist branches from the oil pan to the upper side of the valve operating chamber and the breather chamber after passing through the oil pump driving gear chamber. 4. Breather structure.