JP2001254722A - Motive power transmission device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve durability of a motive power transmission system part and a motive power transmission device by eliminating deflection of a shaft end of one crankshaft for fixing a primary drive gear of an internal combustion engine having a pair of the crankshafts. SOLUTION: This motive power transmission device of an internal combustion engine 1 has a pair of the crankshafts 22, 25 connected to each other by meshing of interlocking gears 27, 28 fixed on respective crankshafts. A primary drive gear 29 is fixed on the one crankshaft 25 of a pair of the crankshafts 22, 25 and output of the internal combustion engine 1 is transmitted to a transmission 3 through meshing of the primary drive gear 29 with a primary driven gear 30 on the side of the transmission 3 and a clutch 34. A bearing 60 is arranged on the shaft end for fixing the primary drive gear 29 of the crankshaft 25. A bearing using a needle roller bearing 63 is used for this bearing 60 and the clutch 34 is arranged adjacent to the bearing 60.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission device for an internal combustion engine, and more particularly to a power transmission device for an internal combustion engine having a pair of crankshafts in which a bearing structure of an output side crankshaft is improved.

[0002]

2. Description of the Related Art Conventionally, an internal combustion engine has a pair of crankshafts, and the pair of crankshafts are connected by meshing of interlocking gears fixed to each crankshaft. An internal combustion engine in which a primary drive gear is fixed to one of the crankshafts, and the output of the internal combustion engine is transmitted to the transmission via a clutch and a mesh between the primary drive gear and the primary driven gear on the transmission side. (See Japanese Patent Publication No. 63-56407).

[0003]

In such a conventional power transmission device for an internal combustion engine, the shaft end of one output side crankshaft to which the primary drive gear is fixed is
The engine was cantilevered in spite of heavy load due to the concentrated output of the engine. For this reason, the deflection of the shaft end becomes large, and the durability of the power transmission system components may be impaired by the vibration caused by the deflection.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the conventional power transmission device for an internal combustion engine, and eliminates the swing of the shaft end of one output side crankshaft to which the primary drive gear is fixed. Another object of the present invention is to provide a power transmission device for an internal combustion engine that can improve the durability of a power transmission device by pulling a power transmission system component.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a power transmission device for an internal combustion engine which has solved the above-mentioned problems. A crankshaft, wherein the pair of crankshafts are coupled by meshing of interlocking gears fixed to each crankshaft, and a primary drive gear is fixed to one of the pair of crankshafts. An output of the internal combustion engine is transmitted to the transmission through a mesh between the primary drive gear and a primary driven gear on the transmission side and a clutch; A bearing is arranged at the shaft end on the side where the primary drive gear is fixed. A power transmission apparatus for an internal combustion engine characterized in that it.

According to the first aspect of the present invention, the shaft end of one of the crankshafts to which the primary drive gear is fixed is securely supported by the bearing. As a result, the shaft end does not vibrate despite the fact that all the output of the engine is concentrated and a large load is applied, the vibration due to the vibration is eliminated, and the power transmission system components The durability of the device can be improved.

According to the second aspect of the present invention, the bearing is a bearing using a needle roller bearing, and the clutch is disposed adjacent to the bearing.

As a result, it is possible to make the bearing at the shaft end of the one of the crankshafts to which the primary drive gear is fixed relatively small. Can be arranged adjacent to the bearing while avoiding mutual interference with the bearing, and this can contribute to downsizing of the internal combustion engine.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the invention described in claims 1 and 2 of the present application shown in FIGS. 1 to 4 will be described below. 1 is a left sectional view of an internal combustion engine to which the power transmission device according to the present embodiment is applied, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIG. 3 is a left cover of the internal combustion engine of FIG. FIG.
FIG. 3 is a partially enlarged view of FIG. 2.

1 to 3, an internal combustion engine 1 to which a power transmission device according to the present embodiment is applied is a spark-ignition, water-cooled, air-cooled, two-cycle V-type two-cylinder internal combustion engine. The motorcycle is mounted on a motorcycle with the direction facing forward of the vehicle, and a transmission 3 is integrally provided behind the internal combustion engine body 2.

The first crank chamber 6 of the first cylinder 4 which is directed obliquely forward and upward of the internal combustion engine body 2 and the second crank chamber 7 of the second cylinder 5 which is directed obliquely downward and forward are formed at the top of a V-shape. The crankcases which are arranged adjacent to each other in the region and define the respective chambers are united to form one unit case 8. The unit case 8 includes first and second units.
Immediately behind the united crankcase combining the crankcases 6 and 7, a transmission chamber 9 for housing the mechanical components of the transmission 3 is integrally provided.

Therefore, the unit case 8 has the first and second crank chambers 6 and 7 and the transmission chamber 9 therein.
And first and second intake passages 10, 11 above and below the front and rear sides thereof.
And is formed integrally by casting as a large block body, and also serves as a combined crankcase (hereinafter simply referred to as a crankcase) and a transmission case that define a combined crankcase. The first and second intake passages 10, 11 are
Arranged in a V-shape that is open to the rear, a reed valve is attached to their inlets.

On the opening sides of the first and second crank chambers 6 and 7 of the unit case 8, mating surfaces A and B are formed, respectively, and these mating surfaces A and B are formed on the first cylinder 4 side. First
The cylinder block 12 and the second cylinder block 13 on the second cylinder 5 side are connected to each other and are integrally connected by bolts (not shown). First and second cylinder blocks
First and second cylinder heads 14 and 15 are further integrally connected to 12 and 13 by bolts (not shown).

When the internal combustion engine 1 is operated, the first intake passage
The air-fuel mixture (intake air) sucked into the first crank chamber 6 through 10 is primarily compressed here, and in a process in which the first piston 16 changes from descending to ascending in the cylinder bore 56, the scavenging port
It is sent to the combustion chamber 18 via 17. At this time, the combustion chamber 18
The remaining combustion gas is expelled by the entry of a new air-fuel mixture and discharged from the exhaust port 19.

Next, when the first spark plug 20 ignites the new air-fuel mixture sent into the combustion chamber 18, the air-fuel mixture explodes, and the first piston 16 descends. Then, the combustion gas is exhausted from the exhaust port 19, and a new air-fuel mixture is supplied from the scavenging port 17 to the combustion chamber 18, and the residual air in the combustion chamber 18 is scavenged by the new air-fuel mixture.

On the other hand, the reciprocating motion of the first piston 16 from lowering to rising and from rising to lowering is transmitted to the first crankshaft 22 via the first connecting rod 21 and is converted into rotational motion by the first crankshaft 22. Is done. The same applies to the operation of the second piston 23, the second connecting rod 24, the second crankshaft 25, and the second spark plug 26 on the second cylinder 5 side.
Detailed description is omitted.

The first transmitted to the first crankshaft 22
The engine output of the cylinder 4 is supplied to the first interlocking gear 27 fixed to a portion of the first crankshaft 22 protruding from the unit case 8 and to a portion of the second crankshaft 25 protruding from the unit case 8. Fixed second interlocking gear
And a primary driven gear 29 fixed to the same portion at one end of the second crankshaft 25 and adjacent to the second interlocking gear 28 and a primary driven gear 30 serving as an input gear to the transmission 3. And transmitted to the transmission 3.

The engine output of the second cylinder 5 transmitted to the second crankshaft 25 is the primary drive gear.
The transmission is transmitted to the transmission 3 through the engagement of the primary driven gear 30 with the gear 29.

Thus, the second crankshaft 25
The engine output of the first cylinder 4 and the engine output of the second cylinder 5 are concentrated on the part where the interlocking gear 28 and the primary drive gear 29 are fixed, and the combined output is transmitted to the transmission 3. Since the relay unit is used, a large load is applied. Primary drive gear 29
The second crankshaft 25 to which is fixed may be referred to as an output-side crankshaft in this specification.

In this manner, the engine output of both the first and second cylinders 4 and 5 transmitted to the transmission 3 is reduced based on the reduction ratio due to the engagement of the predetermined gears in the transmission 3, and the counter shaft The sprocket 33 is taken out from a sprocket 33 fixed to a portion protruding from the unit case 8 at one end. The power is transmitted to the rear wheels via a chain suspended between the sprocket 33 and a sprocket (not shown) fixed to the rear wheels of the vehicle.

Reference numeral 34 denotes a clutch for intermittently transmitting the engine output between the primary driven gear 30 and the main shaft 31 of the transmission 3. Reference numeral 35 denotes a shift mechanism for changing the meshing of the gears. And a shift cam.

The first and second crankshafts 22, 25 are laid horizontally in the left-right direction when viewed in the vehicle traveling direction, and are rotatably supported by a crankcase (the crankcase portion of the unit case 8). Especially the second crankshaft 25
As described above, since a large load is applied to one end where the second interlocking gear 28 and the primary drive gear 29 are fixed, the bearing 60 is provided to support the shaft end.

As the bearing 60, an internal recess 61 formed by bulging a part of a cover 54 covering the left side of the internal combustion engine 1 is used. In this recess 61, a bearing case 62 is provided with a needle roller bearing 63. (See FIGS. 2 and 4). The left cover 54 is a first and second interlocking gear.
27, 28, the primary drive gear 29, the primary driven gear 30, etc., are covered with the primary power transmission chamber 53.

Since the needle roller bearing 63 is used as a component of the bearing 60, the bearing 60 can be configured to be relatively small, and the clutch 34 can be mounted by utilizing the space thus vacated. It can be easily arranged adjacent to the bearing 60 while avoiding mutual interference with the bearing 60. Instead of the needle roller bearing 63, a sliding bearing may be used, and a roller bearing may be used.

The other end of the second crankshaft 25 (the end opposite to the side where the second output gear 28 and the primary drive gear 29 are fixed) protrudes from the unit case 8,
The impeller 37 of the cooling water pump 36 is integrally connected.
The impeller 37 is covered by a pump cover 38, and a pump chamber 39 is formed around the impeller 37. Therefore, the cooling water pump 36 is driven to rotate by the second crankshaft 25.

The engine cooling water cooled by a radiator (not shown) is guided into the internal combustion engine 1 by a cooling water pump 36, is pressurized by the cooling water pump 36, and is discharged from a pump formed on the right wall of the unit case 8. After flowing through a passage (not shown), the water flows into the inlet water chambers 41 and 42 forming the starting ends of the cooling water passages 43 and 44 that surround the first and second crank chambers 6 and 7 after being divided in two directions.

Then, it flows along the periphery of the first and second crank chambers 6 and 7 from there, and cools a partition wall 55 that partitions between the first and second crank chambers 6 and 7 and the transmission chamber 9. . As a result, heat from the transmission chamber 9 to the first and second crank chambers 6 and 7 is cut off, the temperatures of the first and second crank chambers 6 and 7 are stabilized, and the primary and second crank chambers 6 and 7 are sucked into these chambers and The temperature rise of the air-fuel mixture to be compressed is prevented. In FIG. 1, all the passages 41 to 44 through which the cooling water flows are marked with coarsely distributed points.

The cooling water flowing through the cooling water passages 43 and 44 around the first and second crank chambers 6 and 7 is then referred to as the first and second intake passages 10 and 11 of the unit case 8. Intermediate water chambers 4 formed near the mating surfaces A and B on the opposite side, respectively.
5, flow into 46. Then, after exiting these intermediate water chambers 45 and 46, the first and second cylinder blocks 12, 13 and the first and second cylinder heads 14 pass through the communication passages passing through the mating surfaces A and B. , 15 are respectively fed into water jackets 47, 48 formed in communication with the first and second water jackets 47, 48.
Cylinder blocks 12 and 13, first and second cylinder heads 1
Cool 4,15. Then, the first and second cylinder heads 1
The coolant flows into the radiator inlet pipe from the cooling water outlets 49 and 50 formed in the pipes 4 and 15, respectively, is cooled in the radiator, and is returned to the internal combustion engine 1 again.

[0029] The internal combustion engine 1 also has a cooling structure using the traveling wind as a cooling source. Although not shown in detail, this air cooling structure is provided on the left wall of the unit case 8 in a first side view.
A cooling air passage 57 is formed so as to go around the second crank chambers 6 and 7, and the primary power transmission chamber 53 and the first and second cranks are driven by the traveling wind flowing through the cooling air passage 57. The left wall portion of the unit case 8 that separates the chambers 6 and 7 is cooled, heat from the primary power transmission chamber 53 to the crank chambers 6 and 7 is cut off, and the temperature rise of the crank chambers 6 and 7 is further prevented. Can come off. FIG. 2 shows a part of the cooling air passage 57 in two places.

The cooling air passage 57 has a cooling air inlet at the front of the left wall of the unit case 8 in front of the first and second crankshafts 22 and 25. , 25, and two cooling air discharge ports that are respectively directed obliquely upward and downward behind the crankcase (the crankcase portion of the unit case 8). The traveling wind is introduced from the cooling air inlet, flows vigorously in the cooling air passage 57, and is discharged from the cooling air outlet.

Since the power transmission device of the present embodiment is configured as described above, the following effects can be obtained. The internal combustion engine 1 has a pair of crankshafts 22 and 25
And a pair of first and second interlocking gears 27, 28 fixed to each crankshaft.
A primary drive gear 29 is fixed to one output side crankshaft 25 of the pair of crankshafts 22 and 25, and the primary drive gear 29 and the primary driven gear 30 of the transmission 3 are connected to each other. Through the meshing and clutch 34
In the power transmission device of the internal combustion engine 1 in which the output of the internal combustion engine 1 is transmitted to the transmission 3,
A bearing 60 is arranged at the shaft end of one output side crankshaft 25 on the side where the primary drive gear 29 is fixed.

As a result, one output side crankshaft
Since the shaft end on the side where the 25 primary drive gears 29 are fixed is securely supported by the bearing 60, the shaft end is shaken despite the fact that all the output of the engine is concentrated and a large load is applied. And the vibration caused by the runout is eliminated, and the first and second interlocking gears 27 and 28, the primary drive gear 29, the primary driven gear 30, the clutch
By pulling the power transmission system components such as 34, the durability of the power transmission device can be improved.

The bearing 60 is a bearing using a needle roller bearing 63, and a clutch is provided adjacent to the bearing 60.
Since the bearings 34 are disposed, the bearing 60 can be configured to be relatively small, and the clutch 34 can be disposed adjacent to the bearing 60 while avoiding mutual interference with the bearing 60 by using the space thus vacated. The internal combustion engine 1 can be downsized.

Further, in order to dispose the bearing 60, an internal concave portion 61 formed by bulging a part of a cover 54 covering the left side of the internal combustion engine 1 is used, and a needle roller bearing 63 is provided in the concave portion 61. Since the bearing case 62 to be held is housed, the bearing 60 is extremely easy to install, and can be easily arranged in an existing internal combustion engine.

[Brief description of the drawings]

FIG. 1 is a left side sectional view of an internal combustion engine to which a power transmission device according to an embodiment of the present invention described in claims 1 and 2 of the present application is applied.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a left side view of the internal combustion engine of FIG. 1 with a left cover removed.

FIG. 4 is a partially enlarged view of FIG. 2;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Internal-combustion engine, 2 ... Internal-combustion-engine main body, 3 ... Transmission, 4 and 5 ... 1st, 2nd cylinder, 6, 7 ... 1st, 2nd crank chamber, 8 ... Unit case, 9 ... Transmission chamber, 1
0, 11 ... first and second intake passages, 12, 13 ... first and second cylinder blocks, 14, 15 ... first and second cylinder heads,
16 ... 1st piston, 17 ... scavenging port, 18 ... combustion chamber, 19 ...
Exhaust port, 20 ... first spark plug, 21 ... first connecting rod, 22
... first crankshaft, 23 ... second piston, 24 ... second
Connecting rod, 25 ... second crankshaft, 26 ... second spark plug, 27, 28 ... first and second interlocking gears, 29 ... primary drive gear, 30 ... primary driven gear, 31 ... main shaft, 32 ... counter shaft, 33 ... sprockets, 34
... clutch, 35 ... shift mechanism, 36 ... cooling water pump, 37 ...
Impeller, 38 ... Pump cover, 39 ... Pump room, 41, 42 ...
Inlet water chamber, 43, 44 ... cooling water passage, 45, 46 ... intermediate water chamber, 4
7, 48… water jacket, 49, 50… cooling water outlet, 5
3… Primary power transmission room, 54… Left cover, 55… Partition wall, 56
... Cylinder bore, 57 ... Cooling air passage, 60 ... Bearing, 61 ... Inner recess, 62 ... Bearing case, 63 ... Needle roller bearing, A, B ... Mating surface, C ... Space.

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Claims (2)

[Claims] An internal combustion engine has a pair of crankshafts, and the pair of crankshafts are coupled by meshing of interlocking gears fixed to each crankshaft, and one of the pair of crankshafts A primary drive gear is fixed to the crankshaft, and an output of the internal combustion engine is transmitted to the transmission through a clutch between the primary drive gear and a primary driven gear on the transmission side and a clutch. A power transmission device for an internal combustion engine, wherein a bearing is disposed at a shaft end of the one crankshaft on a side to which the primary drive gear is fixed. 2. The power transmission device for an internal combustion engine according to claim 1, wherein the bearing is a bearing using a needle roller bearing, and the clutch is disposed adjacent to the bearing.