JP3193207B2 - Lubricating oil supply device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine having a balancer shaft rotating in synchronization with a crankshaft, and more particularly to an apparatus for supplying lubricating oil to the crankshaft and the balancer shaft in such an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, in order to suppress vibration of an engine, a balancer shaft having an eccentric weight is arranged in parallel with a crankshaft, and the balancer shaft is rotated in synchronization with the crankshaft.

Conventionally, for lubrication of a balancer shaft bearing, a control bolt having a hole formed in a bolt for attaching an orifice, a jet or a pipe as a separate component is provided in an oil passage branched from a lubricating oil main gallery leading to a lubricating oil pump. This is done by lubricating each bearing through these parts, and thereby adjusting the amount of oil to each bearing.

In the internal combustion engine described in Japanese Patent Application Laid-Open No. 2-212327, a central oil passage and a side oil passage are provided below a crankshaft and a balancer shaft in parallel with these shafts, respectively. The oil passages are communicated by a communication oil passage, and oil passages are provided between the central oil passage and the bearings of the crankshaft and between the side oil passages and the bearings of the balancer shaft, respectively. Is connected to a lubricating oil pump.

[0005]

The lubricating oil supply device using the above-mentioned orifice or the like has a complicated lubricating oil passage and a large number of parts, and requires threading and assembling work for inserting the orifice and the like. Man-hours increase. Further, since the flow of the lubricating oil is throttled by the orifice or the like before reaching the oil hole of the bearing, it takes time until the lubricating oil reaches the inside of the bearing after the engine is started.

The structure disclosed in Japanese Patent Application Laid-Open No. 2-212327 has a relatively simple structure of an oil passage and requires only a small number of parts. On the other hand, it is difficult to appropriately adjust the amount of oil to each bearing. is there. In other words, it is desirable that the amount of oil in the bearing of the balancer shaft with a relatively small load be less than the amount of oil in the crank bearing with a large load in order to effectively use the lubricating oil. Can not.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and the present invention relates to an internal combustion engine having a balancer shaft that rotates in synchronization with a crankshaft. A crankshaft and a balancer shaft are vertically supported by a split surface of a crankcase which is divided into upper and lower shafts via flat bearings, and lubricating oil is supplied at least to the crankshaft and the balancer shaft from a lubricating oil pump into oil holes provided in the flat bearings. The oil passage provided exclusively for the crankshaft is provided in parallel, and the opening area of the oil hole provided in the flat bearing of the balancer shaft is made smaller than the opening area of the oil hole provided in the flat bearing of the crankshaft.

According to the present invention, since no separate parts such as orifices and jets are provided in the oil passage, the number of parts and the number of processing and assembling steps are reduced.

In addition, since the opening area of the oil hole of the flat bearing is made smaller on the balancer shaft side and larger on the crankshaft side, an amount of lubricating oil corresponding to the load is distributed and supplied to the balancer shaft side and the crankshaft side. Is used effectively.

Further, since each flat bearing is provided on the split surface of the crankcase, the shape of the oil passage is simplified and its length is shortened, and the amount of oil to each bearing is reduced. Since the control is performed by the oil hole corresponding to the outlet, the time until the lubricating oil reaches the flat bearing after the engine is started is reduced, which is advantageous in terms of the durability of the bearing.

[0011]

FIG. 1 is an overall side view of an internal combustion engine 1 for a motorcycle according to an embodiment of the present invention. Reference numeral 2 denotes a crankcase, which is divided into an upper crankcase portion 2a and a lower crankcase portion 2b by a split surface 3, and these crankcase portions 2a and 2b are integrally fastened by bolts 4. The upper crankcase portion 2a is formed integrally with the cylinder block 5. 6 is a cylinder head, 7 is a head cover, 8 is an intake pipe, and 9 is a carburetor.

An oil pan 10 is connected to the bottom surface of the lower crankcase portion 2b, and an oil filter 11 projects from the front surface. An oil pump (lubricating oil pump) 16 is provided in the crankcase portion 2b.

In the crankcase 2, a balancer shaft 12, a crankshaft 13, a main shaft 14 of a gear transmission and its output shaft 15
Are arranged in order from the front to the rear, and are respectively horizontally oriented in the horizontal direction. All of these shafts 12 to 15 are rotatably supported on the split surface 3 via bearings.

Further, on the upper surface of the cylinder head 6, camshafts 17 for driving an intake valve and an exhaust valve are arranged in parallel with each other.

FIG. 2 shows an oil passage member provided in the lower portion of the crankcase 2 and in the oil pan 10, and a gear transmission having an oil pump 16, the main shaft 14, and the output shaft 15 to which the oil passage member is connected. 2 is a drawing showing a device 18. However, the oil passage member is shown in a side sectional view, but the oil pump 16 is shown in a section along the line IIA-IIA in FIG. 1, and the gear transmission 18 is shown in a section along the line IIB-IIB in FIG. ing.

The suction port 19 of the oil pump 16 communicates with the bottom of the oil pan 10 via a suction pipe 20 and a strainer 21,
The discharge port 22 communicates with the oil filter 11 via a discharge pipe 23. A relief valve 24 for returning excess oil to the oil pan 10 is connected to the discharge pipe 23.The relief valve 24 is surrounded by a rib 25 to prevent the oil stored in the oil pan 10 from foaming due to the returned oil. Preventing.

The lubricating oil fed from the oil pump 16 to the oil filter 11 via the discharge pipe 23 and filtered in the oil filter 11 enters a main gallery 26 extending from the oil filter 11 into the crankcase 2. The main gallery 26 extends below the balancer shaft 12 and the crankshaft 13 in a direction perpendicular to these shafts.

An oil supply passage 27 branching upward at the tip of the main gallery 26 communicates with an oil passage 28a formed in a case wall portion of the gear transmission 18, and passes through the oil supply passage 27 to the oil passage 28a. The lubricating oil that has flowed into the oil tank then flows through oil passages 28b and 28c that are vertically passed through the main shaft 14 and the output shaft 15, and lubricates a required portion around the shaft.

The main shaft 14 has a driven gear 29 and a clutch 30
The rotation of the crankshaft 13 is transmitted via a gear train, and the rotation of the main shaft 14 is transmitted to the output shaft 15 at a desired gear ratio via a gear train appropriately selected and set, and the rotation of the output shaft 15 is
As shown in FIG. 9, the power is transmitted to the rear wheel 63 of the motorcycle 62 via the chain 31 and the chain 32. A sprocket 33 that rotates integrally with the driven gear 29 is mounted on the main shaft 14,
A chain 35 is wound between the sprocket 33 and a sprocket 34 provided on the shaft of the oil pump 16.
Therefore, the oil pump 16 is driven by the driven gear 29 and the sprocket 3
3, crankshaft 13 via chain 35, sprocket 34
Driven by

At a middle portion of the main gallery 26, that is, at a position immediately below the crankshaft 13, a crankshaft oil gallery 36 branches off from the main gallery 26 in the lateral direction.
FIG. 3 is a cross-sectional view of a main part substantially along the line III-III of FIG. 1. As can be seen from this figure, the crank shaft oil gallery 36 extends on both sides of the main gallery 26 in parallel with the crank shaft 13. .

As can be seen from FIG. 3, the internal combustion engine of this embodiment is a two-cylinder engine, and two pistons 37 are connected to the crankshaft 13 via connecting rods 38, respectively. The crankshaft 13 has four flat bearings 39a, 39b, 39c, 39d.
Thus, it is rotatably supported by the crankcase 2.
These flat bearings 39a to 39d are connected to the upper crankcase portion 2
a and the lower crankcase portion 2b along the split surface 3 and between the two portions 2a, 2b.

In the drawing of the crankshaft 13, a driving gear 40 meshing with the driven gear 29 is provided at the right end, and a sprocket 41 for driving the camshaft 17 via a chain is provided at an intermediate portion. I have. And the flywheel on the left end
A start gear 44 is connected to the flywheel 42 via a one-way clutch 43.

Each of the bearing ribs 45a to 45d of the lower crankcase portion 2b supporting the flat bearings 39a to 39d has:
Each of the oil passages 46 extends vertically and communicates with the oil gallery 36 for the crankshaft. The upper ends of these oil passages 46 communicate with oil holes 47 provided in the corresponding flat bearings 39 (FIG. 6).
The contact surface between the flat bearing 39 and the crankshaft 13 is lubricated by the lubricating oil fed to the inner surface of the flat bearing 39 through the shaft. Part of the lubricating oil that has lubricated each flat bearing 39 is discharged from the flat bearing 39 into the crankcase 2 and returned to the oil pan 10.

However, a part of the lubricating oil that has lubricated the flat bearing 39a is guided to the crankpin bearing 49 through an oil passage 48 formed in the crankshaft 13 to lubricate the bearing. A portion of the lubricating oil that has lubricated the flat bearing 39c is similarly guided to the other crankpin bearing 49a to lubricate the bearing. Further, a part of the lubricating oil discharged from the flat bearing 39a reaches the one-way clutch 43 through the crankshaft 13 to lubricate the part. On the other hand, a part of the lubricating oil discharged from the flat bearing 39d enters an oil hole 50 provided in the drive gear 40, and the drive gear 40 and a gear piece 40a provided outside thereof for removing backlash are removed. Lubricate between. Therefore, the drive gear 40
A concave portion 51 is provided on a side surface facing the flat bearing 39d so as to actively collect the lubricating oil in the oil hole 50.

An oil passage 52 extending upward is formed in a bearing rib of the upper crankcase portion 2a corresponding to the flat bearing 39b, and the oil passage 52 bypasses around the flat bearing 39b to form the bearing rib 45b. Oil passage 46. Oil passage 52
Is connected to an oil passage 53 provided along the two camshafts 17, 17 at an upper portion, and the lubricating oil supplied to the camshaft 17 through the oil passages 46, 52, 53 supplies a lubricating oil around the camshaft 17. Required parts are lubricated.

FIG. 4 shows the balancer shaft 12 in the vicinity thereof.
3 is a drawing shown in a vertical cross section including twelve axes. Similar to the crankshaft 13, the balancer shaft 12 is also supported by flat bearings 54 provided on the split surface 3 of the crankcase. The balancer shaft 12 is adjacent to and extends parallel to the crankshaft 13, and a driven gear 55 provided at an end thereof meshes with a drive gear on the crankshaft 13 side, so that the balancer shaft 12 is synchronized with the crankshaft 13. Rotate.

An oil gallery 56 for the balancer shaft is disposed below and in parallel with the balancer shaft 12, and this oil gallery 56 directly intersects with the main gallery 26 like the oil gallery 36 for the crankshaft. Instead, as shown in FIG. 5, at a position higher than the main gallery 26, that is, at a position close to the balancer shaft 12, it extends at right angles to the main gallery 26. The oil gallery 56 for the balancer shaft and the main gallery 26 communicate with each other through a vertical communication path 57. However, the axis of the communication passage 57 is offset toward the crankshaft 13 with respect to the axis of the oil gallery 56 for the balancer shaft. By doing so, the outer end position of the main gallery 26 can also be shifted toward the crankshaft 13 side.
The projecting length of the oil filter 11 connected to the outer end from the engine main body can be shortened. Further, the weight around the oil passage of the crankcase can be reduced, and the rigidity around the balancer bearing increases by providing a dedicated oil passage near the balancer bearing.

An oil passage 58 branches off from both ends of the balancer shaft oil gallery 56 and extends upward.
Oil holes that reach each flat bearing 54 at both ends of the
It communicates with 59 (Fig. 7). However, the opening area of the oil hole 59 is smaller than the opening area of the oil hole 47 of the flat bearing 39 on the crankshaft 13 side.

The driven gear 55 is provided with a gear piece 55a similarly to the drive gear 40 on the crankshaft 13 side, and is provided with oil holes 50a and recesses 51a similar to the oil hole 50 and the recess 51. ing. An oil pressure switch 60 is attached to one end of the balancer shaft oil gallery 56.

FIG. 8 shows the entire lubricating oil supply system described above. The lubricating oil discharged from the oil pump 16 reaches the main gallery 26 via the discharge pipe 23 and the oil filter 11, and from the main gallery 26, on the other hand, the crankshaft 13 via the crankshaft oil gallery 36 and the oil passage 46. On the other hand, it is pressure-fed to the flat bearings 39 and to the flat bearings 54 of the balancer shaft 12 via a balancer shaft oil gallery 56 and an oil passage 58. In other words, since they are sent in parallel to the respective flat bearings 39 and 54, they reach the respective flat bearings at substantially the same pressure. Therefore, the amount of lubricating oil supplied to each flat bearing depends exclusively on the opening area of the oil holes 47 and 59.
A large amount of lubricating oil is supplied to 39 from a flat bearing 54 having an oil hole 59 having a small opening area. Thus, the flat bearing 39 on the crankshaft 13 side, which has a large bearing load and requires a relatively large amount of lubricating oil, and the flat bearing 54 on the balancer shaft 12 side, which has a small bearing load and requires a relatively small amount of lubricating oil, are required. An appropriate amount of lubricating oil can be supplied.

Further, this oil amount adjustment is performed simply by changing the opening areas of the oil holes 47 and 59, and does not require an oil amount adjustment member such as an orifice and a jet, so that the configuration of the lubricating oil system can be simplified. At the same time, the number of parts and the number of processing and assembling steps are reduced.

Further, the flat bearings 39, 54
The oil passage resistance of the lubricating oil is small, and the lubricating oil can reach the flat bearings 39 and 54 quickly after the pump is started.

As shown in FIG. 1, the oil pan 10 is formed deep in the rear part where the strainer 21 is installed and shallow in the front part. As a result, the bottom of the oil pan 10 has a low rear part.
The front is higher. Self-supporting feet 61a and 61b project from the bottom at the rear and front, respectively, so that the entire internal combustion engine 1 can be made independent by the self-supporting feet 61a and 61b during maintenance of the engine alone. .

The internal combustion engine 1 is mounted on the motorcycle 62 with the split surface 3 horizontal as shown in FIG. 9, that is, in the same state as in FIG. In order to make the internal combustion engine 1 self-standing with the split surface 3 substantially horizontal even during maintenance as described above, the front self-standing foot 61b must be lengthened, but in this embodiment, the self-standing foot 61b is shortened. The internal combustion engine 1 is made to stand on its own in a state in which the internal combustion engine 1 is inclined forward by the angle α within a range in which the internal combustion engine 1 does not fall.

[0035]

According to the present invention, the structure of the lubricating oil supply system is simplified, and the number of parts and the number of workings and assembling steps are reduced. In addition, since the lubricating oil can be distributed and supplied to the balancer shaft side and the crankshaft side flat bearings in an amount corresponding to a required amount, the lubricating oil can be used effectively, and each part of the oil can be used. Supply time is shortened and bearing durability is improved

[Brief description of the drawings]

FIG. 1 is an overall side view of a motorcycle internal combustion engine according to one embodiment of the present invention.

FIG. 2 is a drawing showing an oil passage member provided in a lower part of a crankcase and inside an oil pan together with an oil pump and a gear transmission.

FIG. 3 is a cross-sectional view of a main part substantially along the line III-III in FIG. 1;

FIG. 4 is a cross-sectional view of the vicinity of the balancer axis cut by a vertical plane including the axis of the axis.

FIG. 5 is a central vertical sectional view of a lower portion of a crank.

FIG. 6 is a sectional view showing a flat bearing portion of the crankshaft.

FIG. 7 is a sectional view showing a flat bearing portion of the balancer shaft.

FIG. 8 is a drawing showing the entire lubricating oil supply system.

FIG. 9 is an overall side view of a motorcycle equipped with an internal combustion engine.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 2 ... Crank case, 3 ... Split face, 4 ... Bolt, 5 ... Cylinder block, 6 ... Cylinder head, 7
... head cover, 8 ... intake pipe, 9 ... vaporizer, 10 ... oil pan, 11 ... oil filter, 12 ... balancer shaft, 13 ... crankshaft, 14 ... main shaft, 15 ... output shaft, 16 ... oil pump, 17
... Camshaft, 18 ... Gear transmission, 19 ... Suction port, 20 ... Suction pipe, 21 ... Strainer, 22 ... Discharge port, 23 ... Discharge pipe, 24 ... Relief valve, 25 ... Rib, 26 ... Main gallery, 27 ... Oil supply passage, 28 ... oil passage, 29 ... driven gear, 30 ... clutch, 31
... Sprocket, 32 ... Chain, 33,34 ... Sprocket, 35 ... Chain, 36 ... Crankshaft oil gallery,
37 ... piston, 38 ... connecting rod, 39 ... flat bearing, 40 ... drive gear, 41 ... sprocket, 42 ... flywheel, 43 ... one-way clutch, 44 ... starting gear, 45 ... bearing rib, 46 ...
Oil passage, 47 ... oil hole, 48 ... oil passage, 49 ... crank pin bearing, 50 ... oil hole, 51 ... recess, 52, 53 ... oil passage, 54 ... flat bearing, 55 ... driven gear, 56 ... balancer shaft Oil gallery for 57, communication passage, 58 for oil passage, 59 for oil hole, 60 for oil pressure switch, 61 for independent foot, 62 for motorcycle, 63 ...
Rear wheel.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Akira Shigihara, Inventor 1-4-1 Chuo, Wako-shi, Saitama Pref. Inside of Honda R & D Co., Ltd. (72) Tsuneo Akamatsu 1-4-1 Chuo, Wako-shi, Saitama Pref. Inside the Honda R & D Co., Ltd. (72) Inventor Hiroshi Yamaura 1-4-1 Chuo, Wako-shi, Saitama Prefecture Incorporated Honda R & D Co., Ltd. (72) Tomoyasu Sato 1-4-1 Chuo, Wako-shi, Saitama Co., Ltd. Within the Technical Research Institute (58) Field surveyed (Int.Cl. ⁷ , DB name) F01M 1/06 F01M 1/16 F16C 33/10 F16F 15/26

Claims (1)

(57) [Claims] In an internal combustion engine provided with a balancer shaft that rotates in synchronization with a crankshaft, the crankshaft and the balancer shaft are supported by a split surface of a vertically divided crankcase via a flat bearing, Oil passages for exclusively supplying lubricating oil from a lubricating oil pump to at least a crankshaft and a balancer shaft are provided in parallel in oil holes provided in each flat bearing, and an opening area of an oil hole provided in a flat bearing of the balancer shaft is provided. Is smaller than the opening area of an oil hole provided in the flat bearing of the crankshaft.