JP3194989B2 - Balancer 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 a balancer device for reducing the vibration of an internal combustion engine, and more particularly, to a crankshaft having both ends in the axial direction of a balance weight portion supported by a crankcase with a pair of first bearings, A balancer shaft axially supported by the crankcase via a pair of second bearings at respective sides of the first bearing and arranged in parallel with the crankshaft; a primary balancer and a secondary balancer supported by the balancer shaft;
An internal combustion engine comprising: a primary balancer gear for transmitting rotation of a crankshaft to a secondary balancer; a secondary balancer gear for transmitting rotation of a crankshaft to the secondary balancer; and a side cover for covering a side portion of the crankcase. It relates to a balancer device of an engine.

[0002]

2. Description of the Related Art Such a balancer device for an internal combustion engine has already been proposed by the present applicant in Japanese Patent Application No. 2-280152.

[0003]

In the above-mentioned conventional balancer for an internal combustion engine, a primary balancer gear for driving a primary balancer on a front balancer shaft is disposed outside a side wall of a crankcase. Moreover, since the shaft of the cooling water pump is connected to the outer end of the primary balancer gear provided on the front balancer shaft,
There is a problem that the size of the side cover that covers the primary balancer gear and the cooling water pump becomes large, which causes the size of the entire internal combustion engine to become large.

The present invention has been made in view of the above circumstances, and has as its object to reduce the size of a side cover of an internal combustion engine by appropriately laying out a balancer gear and a cooling water pump.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a crankshaft having both ends in the axial direction of a balance weight portion supported by a crankcase with a pair of first bearings, and a pair of the first bearings. A balancer shaft axially supported by the crankcase via a pair of second bearings at the sides of the balancer shaft, and arranged in parallel with the crankshaft; a primary balancer and a secondary balancer supported by the balancer shaft; A balancer device for an internal combustion engine, comprising: a primary balancer gear for transmitting rotation of a shaft; a secondary balancer gear for transmitting rotation of a crankshaft to the secondary balancer; and a side cover for covering a side portion of the crankcase. The balance between the pair of first bearings and
A primary balancer gear is provided on each side of the eight part in the axial direction.
To distribute the primary balancer gear to the secondary balancer gear, the primary balancer gear is placed on one side in the axial direction of the balance weight portion and one of the first balancer gears.
Between the inner bearing, also respectively disposed between the inner side of the first bearing in the axial direction the other side and the other balance weight secondary balancer gear, the one the entire primary balancer <br/> Of the balancer shaft outside of the first bearing, and the balancer gear
While a smaller diameter than eight portions, the secondary balancer, the first characterized in that rotatably fitted and supported at the middle on the balancer shaft of the pair of second bearing.

Further, the present invention provides, in addition to the first feature described above,
A second feature is that a cooling water pump is provided at the other end of the balancer shaft protruding outside from the crankcase, and the cooling water pump is covered by a pump cover mounted on an outer surface of the crankcase.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 4 show an embodiment of the present invention. FIG. 1 is a schematic view of the internal combustion engine (a sectional view taken along line 1-1 in FIG. 4), and FIG. 2 is an enlarged view of a part of FIG. FIG. 3 is an enlarged view of a portion 3 of FIG. 1, and FIG. 4 is a sectional view taken along line 4-4 of FIG.

A crankcase 1 of a single-cylinder four-cycle internal combustion engine E for a motorcycle is divided into a right half 2 and a left half 3, and a cylinder block 4 is connected to an upper portion thereof.
A right side cover 6 is connected to an outer split surface 2a of the right half 2 of the crankcase 1, and a left side cover 7 is connected to an outer split surface 3a of the left half 3 of the crankcase 1.

A pair of first ball bearings 8, 9 provided on the right half 2 and the left half 3 of the crankcase 1, respectively, are rotatable on both axial sides of a balance weight portion 10a of the crankshaft 10. Supported by
Crank pin 1 provided on the balance weight portion 10a
Ob is connected via a connecting rod 11 to a piston (not shown) that slides into the cylinder block 4. An AC generator 12 is mounted on the left end of the crankshaft 10, and two oil pumps 13 and 14 are coaxially connected to the right end thereof.

A main shaft 15 of a transmission functioning as a rear balancer shaft is supported above a rear portion of the crankshaft 10 via a pair of ball bearings 16 and 17, and a countershaft 1 is further provided at a rear portion thereof.
8 is supported in parallel with the main shaft 15 via a pair of ball bearings 19 and 20. The rotation of the crankshaft 10 is input to the main shaft 15 via a clutch 21 provided at the right end of the main shaft 15, and the rotation of the countershaft 18 is output from the sprocket 22 provided at the left end to the rear wheel via a chain 23. Is done. And the main shaft 15 and the counter shaft 18
Five gear trains G for selectively establishing a plurality of gears
₁ ~G ₅ is provided.

At the front of the crankshaft 10, the crankcase 1 is held by the side of the pair of ball bearings 8,9.
The front balancer shaft 26 is supported via a pair of ball bearings 24 and 25 provided as a second bearing provided on the right half 2 and the left half 3, respectively. An impeller 27a of a cooling water pump 27 is press-fitted to the right end of a front balancer shaft 26 that is supported by the right ball bearing 24 and extends outward from the right half 2 of the crankcase 1. The cooling water pump 27 is covered by a cup-shaped pump cover 5 that is coupled to the split surface 2b of the right half 2 of the crankcase 1.

Next, the structure of the balancer device provided in the internal combustion engine E will be described in detail.

The balance weight of the crankshaft 10
Between the portion 10a and the inside of the ball bearing 9 on the left side.
The worn primary balancer drive gear 36 is
Primary balun with the same number of teeth connected to the sensor shaft 26
Meshes with third driven gear 29And these gears 36, 29
Has a smaller diameter than the balance weight portion 10a.
You. Front balancer outside ball bearing 9 on left
At the left end of the shaft 26 is a semicircular front primary inertia balun.
Sir I_F1Are splined together and the crankshaft 10
At the same speed as the crankshaft 10 in the opposite direction.
You.

A secondary balancer drive gear 30 fixed between the balance weight portion 10a of the crankshaft 10 and the inside of the right ball bearing 8 is a secondary balancer driven gear that is rotatably supported on the front balancer shaft 26. 31 and these gears 30, 3
1 also has a smaller diameter than the balance weight portion 10a
Ru is. The secondary balun 3rd gear 31 has a balun.
With Suueito front part 2 primary inertial force balancer I _F2 semicircular facing the outer peripheral surface of 10a is formed integrally with the front secondary by increasing the thickness in a semi-circle in the secondary balancer driven gear 31 Moment balancer M _F2
Is formed. By setting the number of teeth of the secondary balancer drive gear 30 to twice the number of teeth of the secondary balancer driven gear 31, the front secondary inertial force balancer _IF2 and the front secondary moment balancer _MF2 can be cranked. It rotates in the opposite direction to the crankshaft 10 at twice the speed of the shaft 10.

The front secondary inertial force balancer I _F2 and the front secondary moment balancer M _{F2 as the} secondary balancer are used as a balancer shaft between the pair of ball bearings 24 and 25 as the second bearing. Is rotatably fitted and supported on the front balancer shaft 26 of the first embodiment.

The two primary balancer gears 36, 29 and the two secondary balancer gears 30, 31 are symmetrically disposed inside the crankcase 1 on both axial sides of the balance weight portion 10a of the crankshaft 10.

At the right end of the main shaft 15 of the transmission, which extends outward from the right half 2 of the crankcase 1, a primary driven gear 33 integrally connected to a clutch outer 32 is rotatably supported. The driven gear 33 is driven by meshing with the primary drive gear 28 keyed to the right end of the crankshaft 10 extending outward from the right half 2 of the crankcase 1. The primary driven gear 33 is formed with a rear primary inertial force balancer I _R1 by increasing the wall pressure to a semicircular shape. Primary drive gear 2
8 and the primary driven gear 33 have the same number of teeth.
Rear primary inertial force balancer _IR1 is crankshaft 10
At the same speed as the crankshaft 10.

A secondary balancer drive gear 30 connected to the crankshaft 10 is a secondary balancer driven gear 34 supported on the main shaft 15 so as to be relatively rotatable.
, And the secondary balanced third gear 34 meshes with a secondary balanced third gear 35 that is rotatably supported on the counter shaft 18. Main shaft 15
The second balancer third driven gear 34 has a rear secondary moment balancer M by increasing the thickness in a semicircular shape.
_R2 is formed, and a rear secondary inertial force balancer _IR2 is formed in the secondary balance third driven gear 35 of the counter shaft 18 by increasing the thickness in a semicircular shape. The number of teeth of the secondary balancer drive gear 30 is twice the number of teeth of both the secondary balancer driven gears 34 and 35, and the rear secondary inertial force balancer _IR2 and the rear secondary moment balancer _MR2 are the two of the crankshaft 10. Rotate at double speed.

[0020] In the state shown in FIG. 4 (a state of top dead center), the front primary inertial force balancer I _F1 and rear primary inertial force balancer I _R1 is in both the downward position, the crankshaft 10 from there in the same phase Rotates counterclockwise at the same speed as.

[0021] As apparent from FIG. 1, 1 a pair of secondary inertial force balancer I _F2, I _R2 in the top dead center of the pair
The next inertial force balancers I _F1 and I _R1 are in phase with
The second moment balancer M _F2 has a phase advanced by 90 ° with respect to the front secondary inertial force balancer I _F2 , and the rear second moment balancer M _R2 has a phase difference of 180 ° with respect to the front second moment balancer M _F2 . have. And
The secondary balancer _{I F2, I R2, M F2} , M R2 1 primary balancer I _F1, rotates at twice the speed of the I _R1.

Next, the operation of the embodiment of the present invention having the above-described configuration will be described.

[0023] With the rotation of the crankshaft 10, the front primary inertial force balancer I _F1 and rear primary inertial force balancer I _R1 rotates at the same speed as the crankshaft 10, and a front secondary inertial force balancer I _{by F2} and the rear secondary inertial force balancer I _R2 rotates at twice the speed of the crankshaft 10, a primary component and secondary component of inertia force generated by the acceleration motion of the reciprocating parts by mass of the piston or the like is canceled Thus, the vibration of the internal combustion engine E is reduced. The front second moment balancer _MF2 and the rear second moment balancer M _{F2
When R2} rotates at twice the speed of the crankshaft 10, two moments generated based on the inertia force are generated.
The next component is canceled, and the vibration of the internal combustion engine E is reduced.

[0024] Now, the primary balancer gear 36,29 for driving the front primary inertial force balancer I _F1 provided on the front balancer shaft 26 supports the balance weight 10a and the crankshaft 10 of the crankshaft 10 is disposed between one of the ball bearing 9, and the front secondary inertial force balancer I _F2 and the front second moment driving the balancer M _F2 secondary balancer gear 30 and 31 provided on the front balancer shaft 26 Is disposed between the balance weight portion 10a of the crankshaft 10 and the other ball bearing 8 supporting the crankshaft 10, so that the thicknesses of the primary balancer gears 36 and 29 and the secondary balancer gears 30 and 31 are reduced. It is distributed to both sides in the axial direction of the balance weight portion 10a of the crankshaft 10. As a result, the length of both spans of the crankshaft 10 sandwiching the balance weight portion 10a is made uniform, so that the strength of the crankshaft 10 can be improved.

The primary balancer gears 36, 29
The secondary balancer gears 30 and 31 are all housed inside the crankcase 1, so that the size of the right side cover 6 that covers the side surface of the crankcase 1 can be reduced. That is, the primary balancer driven gear 29 is provided at the right end of the front balancer shaft 26 as in the prior art, and the primary drive gear 2 at the right end of the crankshaft 10 is provided.
8, the primary balance third driven gear 2
It is necessary to extend the right side cover 7 to the front end of the crankcase 1 in order to cover the right side cover 9, resulting in an increase in the size of the right side cover 7. However, in the present invention, since the primary balance third driven gear 29 is disposed on the left side of the front balancer shaft 26, it is not necessary to cover the primary balance third driven gear 29 with the right side cover 7, and the size of the right side cover 7 is reduced. The size can be reduced.

Further, the cooling water pump 27 is directly mounted on the right end of the front balancer shaft 26, and the front balancer shaft 26 is used as the shaft of the cooling water pump 27. In combination with the arrangement of the cooling water pump 27 on the right side in the axial direction, the width of the front part of the crankcase 1 can be reduced in combination with the arrangement on the left side of the partial balancer shaft 26.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the present invention described in the appended claims. It is possible to make design changes.

For example, in the embodiment, the two split surfaces 2a and 2b formed on the outside of the right half portion 2 of the crankcase 1 have a slight step. Simplification and improvement in processing accuracy can be achieved. Further, it is also possible to integrate the right side cover 6 and the pump cover 5 connected to the split surfaces 2a and 2b.
Further, the impeller 27a of the cooling water pump 27 is fastened to the right end of the front balancer shaft 26 by a screw, so that the assembling property and the maintenance property can be improved.

[0029]

As described above, according to the first aspect of the present invention, the primary balancer gear is provided between one side of the balance weight portion in the axial direction and the inside of one of the first bearings. also each arranged to kites between the inner first bearing axial other side and the other balance weight secondary balancer gear
The balance between the pair of first bearings and the balance
A primary balancer gear and 2
The balancer gear and the next balancer gear can be distributed approximately symmetrically in a well-balanced manner . As a result, there is no need to store the balancer gear inside the side cover that covers the side of the crankcase. Not only the size of the side cover is reduced, but also the length of both spans of the crankshaft sandwiching the balance weight portion is made uniform, and the strength of the crankshaft is improved.

Also, in particular, the entire primary balancer is
The secondary balancer gear is connected to one end of the balancer shaft outside the bearing, and the secondary balancer gear is smaller than the balance weight.
And forming a radial, secondary balancer, since rotatably fitted and supported on the balancer shaft in the middle of the pair of second bearing, the primary balancer comprising a relatively large diameter all
Body is in the axially outer side of the first bearing, on that can be avoided without difficulty interference with the large diameter of the balance weight section of the crankshaft, the secondary balancer located between the second bearing, long enough in the axial direction while avoiding interference with the primary balancer (thus minimizing the radial direction) can be formed, yet the balun secondary balancer Giya
Arrange on one side in the axial direction instead of the outer periphery of the weight
Because the diameter is smaller than the weight, the secondary balancer
-Distance between shafts between gears while ensuring necessary gear ratio
The separation can be minimized. As a result, while avoiding each interference between the secondary balancer , the balance weight section , and the primary balancer, and requiring the secondary balancer gear,
While maintaining the gear ratio, the center distance between the crankshaft and the balancer shaft can be reduced as much as possible, which can greatly contribute to downsizing of the balancer device.

According to the second feature of the present invention, since the cooling water pump is directly supported on the balancer shaft, a special cooling water pump shaft is not required, and the number of parts is reduced. In addition, since the cooling water pump is covered with the pump cover, there is no need to cover the cooling water pump with the side cover of the crankcase, so that the size of the side cover can be further reduced.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an internal combustion engine according to one embodiment of the present invention (a sectional view taken along line 1-1 in FIG. 4).

FIG. 2 is an enlarged view of a part of FIG. 1;

FIG. 3 is an enlarged view of a part of FIG. 1;

FIG. 4 is a sectional view taken along line 4-4 in FIG. 1;

[Explanation of symbols]

1 ... Crankcase 5 ... Pump cover 6 ... Right side cover (side cover) 7 ... Left side cover (side cover) 8 ... Ball bearing (1st bearing) 9 ... ball bearing (first bearing) 10 ... crankshaft 10a ... balance weight section 24 ... ball bearing (second bearing) 25 ... ball Bearing (second bearing) 26 front balancer shaft (balancer shaft) 27 cooling water pump 29 primary balance third driven gear (primary balancer gear) 30 secondary balancer Drive gear (secondary balancer gear) 31... Secondary balancer third driven gear (secondary balancer gear) 36. Sir drive gear (primary balancer gear) I _F1 · · · · anterior primary inertial force balancer (primary balancer) I _F2 · · · · front secondary inertial force balancer (secondary balancer) M _F2 · · ·・ Front second moment balancer (secondary balancer)

Claims (2)

(57) [Claims] 1. A crankshaft (10) having both ends in the axial direction of a balance weight portion (10a) supported on a crankcase (1) by a pair of first bearings (8, 9), and a pair of first bearings (8). , 9), a pair of second bearings (24, 2) are respectively attached to the crankcase (1).
5) via axially supported by crankshaft (10) and aligned parallel balancer shaft (26), a primary balancer that supports this balancer shaft (26) (I _F1) and a secondary balancer (I _F2, M _F2 ) and the 1-order balancer (primary balancer gear for transmitting the rotation of the crankshaft (10) to the I _F1) (36,29), the secondary balancer (I _F2, M _F2) to the crankshaft (10) Secondary balancer gears (30, 31) for transmitting the rotation of
In a balancer device for an internal combustion engine comprising a side cover (6, 7) for covering a side portion of the crankcase (1), a balance weight is provided between a pair of first bearings (8, 9).
A primary balancer is provided on each side of the unit (10a) in the axial direction.
-Gears (36, 29) and secondary balancer gears (30, 3)
In order to sort out 1), the primary balancer gear (36,
29) between the axial side of the balance weight portion (10a) and the inside of one of the first bearings (9), and the secondary balancer gears (30, 31) in the axial direction of the balance weight portion (10a). The other bearing and the other first bearing (8)
Respectively disposed between the inner and the whole primary balancer (I _F1) attached to one end of the balancer shaft (26) outside of said one of the first bearing (9), secondary balancer gear (30 , 31)
Parts as well as a diameter smaller than (10a), the secondary balancer (I _F2, M _F2), said pair of second bearing (2
A balancer device for an internal combustion engine, wherein the balancer device is rotatably fitted and supported on a balancer shaft (26) in the middle of the balancer (4, 25). 2. A cooling water pump (27) is provided at the other end of the balancer shaft (26) projecting outside from the crankcase (1), and the cooling water pump (27) is connected to the outside of the crankcase (1). 2. The balancer device for an internal combustion engine according to claim 1, wherein the balancer device is covered by a pump cover mounted on a side surface.