JPS5839835A - Balancer for three-cylinder engine - Google Patents

Abstract

PURPOSE:To decrease vibration of an engine and reduce the weight and size of a balancer by providing a balancer shaft which rotates in the direction opposite to a crankshaft with two sets of balancers divided into two parts corresponding to bearings on the first and the third cylinders side and using both outer side balancers also as bearings. CONSTITUTION:Crank arms of the first, and the third cylinders of a crankshaft 1 are provided with counterweights 6a-1, 6a-2; 6c-1, 6c-2 and 6a'-1, 6a'-2: 6c'-1, 6c'-2 in relation to a mass of rotary parts and reciprocating parts of an engine respectively. The crank arm of the second cylinder is also provided with counterweights 6b-1, 6b-2 in relation to the mass of rotary parts only. Further, one balancer shaft 7 is provided which rotates at an equal speed and in the opposite direction in relation to the crankshaft 1. The balancer shaft 7 is provided with balancers 8a'-1, 8a'-2, and 8c'-1, 8c'-2 divided into two parts corresponding to two pairs of bearings 9a, 9b and 9c, 9d of the first, the third cylinders. The outermost balancers 8a'-1, 8c'-2 are supported in the entire periphery-shaped shaft pipe and used as both balancers and bearings 23.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a 3-cylinder automobile engine with a counterweight on the crankshaft itself, and a balancer shaft that rotates at the same speed and in the opposite direction to the crankshaft.
Relating to a balancer device that balances the first-order inertia force due to the reciprocating and rotating mass of each cylinder and the first-order inertia couple around the X-axis, and also balances the first-order inertia couple in the longitudinal direction of the crankshaft. There are many things.

In each cylinder, there is an inertia force due to the reciprocating Stt amount and the rotating mass.The inertia force due to the rotating mass can be balanced out by placing a counterweight on the opposite side of the crank arm, and the inertia force due to the reciprocating mass is It is possible to half-balance at the same position as with a rotating mass, and balance the remaining part with a balancer shaft that rotates in the opposite direction at the same speed as the crankshaft. By the way, in the case of a 3-cylinder engine, the inertial force of 8 air am is balanced as described above, and at the same time
Even if the inertia couple around the shaft is also balanced, an inertia couple in the longitudinal direction occurs, and in order to balance and remove this inertia couple, the counterweight of the crankshaft has been specified, for example, as in Japanese Patent Application Laid-Open No. 55-6035. There is a separation structure as disclosed in Japanese Patent Publication No. 54-2333, in which an inertia couple of the same magnitude and opposite direction as the inertia couple of the crankshaft system is generated on the balancer shaft to cancel it out.

The above is related to the balance of inertia force and inertia couple, which is generally said to be the case in a three-cylinder engine. In other words, in an engine with an odd number of cylinders, such as a three-cylinder engine, the inertial forces of the first and third cylinders act symmetrically on both sides of the second cylinder, which is located in the middle. The inertial couple must be taken into account, and this has a large effect on engine vibration. On the other hand, the longitudinal eccentric force of swinging due to this inertial force can be balanced by the balancer on the balancer shaft, but in this case, even if the couple is constant, the mass can be increased according to the distance between the balancers, so By specifying the mounting position of the balancer, it becomes very advantageous in terms of the structure of the balancer shaft itself, design flexibility, arrangement relation to the crankshaft, etc.

In view of these circumstances, the present invention achieves balance against the inertial force and inertial couple by using a counterweight on the crankshaft and a balancer on the balancer shaft, and also brings the balancer shaft closer to the crankshaft side, and also improves its II - miniaturization and history. It is an object of the present invention to provide a balancer device for a three-cylinder engine which is advantageous for supporting bearings and can prevent inconveniences when the balancer shaft is immersed in oil.

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings. First, to explain the balance system per cylinder in Fig. 1, in the figure, numeral 1 is the crankshaft, 2 is the crank arm sequentially arranged at equal intervals of 120°, 3 is the crank bin, 4 is the cylinder, and 5 is the cylinder. It is a piston, and a counterweight 6 is provided on the extension line of the crank arm 2 on the opposite side from the crank bin 3 to half balance the entire inertial force due to the rotating mass and the inertial force due to the reciprocating mass. Further, one balancer shaft 7 is provided which rotates in the opposite direction at the same speed as the crankshaft 1, and a balancer 8 is provided which half-balances the remaining part of the inertial force due to the tl return mass. As shown in the figure, when the crank arm 2 is positioned clockwise by θ from the top of the Z-axis, the balancer 8 of the balancer shaft 1 is positioned counterclockwise by the same amount θ from the bottom of the Z-axis. here,
The inertia mass of the reciprocating part is -p, and to make the explanation easier to understand, the equivalent inertia mass of the crank bin 3 of the rotating part is -C.
Then, the counterweight 6 on the crankshaft side should be half-balanced for ttllillsp, so -p/2, and for the rotating mass -C, it rotates in the same direction as the crankshaft 1, so its I was able to balance everything and it became -C, and the total was (sp/2) + a
c. Also, the quality of the balancer 8 on the balancer shaft side is the remainder of the above-mentioned reciprocating mass and becomes imp/2.

By doing this, the Z of the reciprocating part and the rotating part.

The inertial forces in the Y direction are all balanced. Therefore 3
In a cylinder engine, if the counterweight 6 and balancer 8 for each of the above-mentioned components are attached to the positions corresponding to each cylinder, then in this case, the total quality of the h runt weights on the crankshaft side is 3 ((■p/2) 0 mc ), the total balancer mass on the balancer shaft side is (3/2)ap.

Next, the balance by mass of the reciprocating part in a three-cylinder engine will be explained with reference to Fig. 2. In Fig. 5, the first to third cylinders are
, and the second cylinder is at top dead center, the first cylinder is rotated 240 degrees from it, and the third cylinder is rotated 120 degrees.
It is in a rotated position.

Therefore, when the cylinder moves by θ from this state, the excitation force Fpl of the first cylinder, the excitation force Fp2 of the second cylinder, and the excitation force Fl)3 of the third cylinder are as follows.

Fpl=ipr oo2 cos (θ −to2
40) F p2-*prω2 CO3θ Fp3-Kasumipr oa2 cos (θ + 1
20) Therefore, the total inertial force is balanced by F p1 + F p2 + F p3 = 0.

In addition, in order to give the inertia couple in the longitudinal direction of the crankshaft a -membrane property, it is viewed from a point P separated by a distance of 1IIS from the first cylinder, and the pitch of each cylinder is set to 1. Then, Fpl・S+Fp2(S+1) +Fp3(S+21)
It is indicated by.

That is, 6-Fpl・S+Fp2(S+1)+Fp3(S+2 L
)=-Jmapr oo2 L sin θ--
-(1), and due to the reciprocating mass which is a weight in two directions, Y
A longitudinal bias force around the axis occurs.

To explain the balance by mass of the counterweights 6a, 6b, and 6c that are half-balanced for each cylinder in FIG. 3, the case where the second cylinder is at top dead center is shown as in FIG. counter weight 6
a, 6b, 6c are crank arms 2a, 2b.

It is located at a position 180° in phase with respect to 2C. Therefore, in the 7 directions when moving by θ from this state, depending on the mass of each counterweight)) Frecl, FreC2,
Frec3 becomes as follows.

Frecl-(sp/2) r ω2 cos (θ
+240 +180 ) Frec2= (g+p/2
) r ω2 cos (θMo180) Frec3-
(sp/2) r ω2 cos (θ
→ 120 + 180 > Therefore, the inertial force in the Z direction is balanced as FrecI+Frec2+Frec3=0.

On the other hand, when the inertia couple in the longitudinal direction due to h in two directions is obtained in the same manner as above, Frecl-S+Frcc2(S0L)+Frec3
(S+21) = (Jj/2) mpr oa2L sinθ--
-(2a), which similarly produces a longitudinal couple around the Y axis.

In addition, the counterweights 6a, 6b, and 6c have components not only in the Z direction but also in the Y direction, and the inertia force is balanced in the Y direction, and the inertia couple in the longitudinal direction due to the force in the Y direction is as follows. .

-(Ji/2) ipr ω21. -cosθ---
(2b) That is, a longitudinal couple around the Z axis is generated due to the force in the Y direction.

Above, the counterweights 6a to 6C on the crankshaft side
The inertia couple in the longitudinal direction generated by the above is generated around the Y axis due to the Z direction and around the Z axis due to the Y direction, and the combination of both is as follows.

(Jj/2) -pr ω2 1 sin
θ − (j'j/2)a+pr×ω2l−cosθ = (F4/2) iprω2 L (sinθ−
cos θ)...(3) By the way, the above-mentioned counterweight on the crankshaft side is not only provided for each cylinder, but also separately set and collected in the first and third cylinders on both sides except for the second cylinder in the center. It is also possible to do this, and this case will be explained with reference to FIG. To state the results without explaining the progress in progress, the counterweights 11J and 6 pi of the first and third cylinders are (J'N/2) (
sp/2), the counterweight side of the first cylinder is at a position further 30' phase advanced from the position 180° phase advanced from the crank arm 2a, and the counterweight side of the third cylinder is 180 degrees ahead of the crank arm 2a. is provided at a position 30 degrees behind the position where the crank arm 2C is 180 degrees ahead of the crank arm 2C. That is, both counterweights u and 6σ are at positions 180° opposite to the crankshaft 1 and perpendicular to the central crank arm 2b.

In this case as well, Z when moving by θ from the state shown in the figure
The force Frecl' due to each direction of the force
, Frec3' is Frec1' = (j'i/
2 > (19/2) r ω'xcos(θ+2
40 + 180 + 30) 9-trec3. ' = (ji/2) (Iall
/2) r ω2xcos(θ+120 + 18
0-. 30), and the two-direction inertial force becomes F recl' + F rec3' = Q, which naturally balances out.

Next, the longitudinal inertia couple due to the force in the 7゛ direction is Frec1'-80Frec3' (S+l L
) = (J'i/2) apr (1321,
sin θ, which agrees with equation (2a).

Even in the Y direction, the inertia force [balanced], the longitudinal inertia couple due to the force in the Y direction is consistent with equation (2b).

From this, the counterweight on the crankshaft side is 1il for each cylinder! It is understood that even if one is provided for each cylinder, or one is provided only for the 1st and 3rd cylinders, the inertia forces are balanced and the inertia couple in the longitudinal direction becomes the same.

Above, we have explained the active force in the crankshaft, the balance of the inertial force by the counterweight, the longitudinal inertia couple, that is, the whirling. will remain, and when they are combined, -5g+pr ω'Lsin θ + (JM/2
) spr ω2xl(sinθ−CO8θ) =−<m/2 )■p”ω' L (sino+cos
θ)...(This is a rumor. Therefore, we will explain how to balance such longitudinal eccentric force on the balancer shaft side using Fig. 5. First,
The balancer shaft 7 also has a balancer 8a corresponding to each cylinder.
, 8b, and 8c, the mass of each balancer 8a to 8c is -D/2 with respect to the reciprocating mass on the crankshaft side. Further, as shown in the figure, when the second cylinder is at the top dead center, the balancer 8b corresponding to the second cylinder is at the opposite position on the bottom dead center side, and the balancer 8a corresponding to the first cylinder is at the opposite position.
is further 180° from the position where the phase has advanced 240° counterclockwise.
The balancer 8c corresponding to the third cylinder is rotated counterclockwise in the shifted position.
4th place 1w with a further 180° phase advance from the 120° position
It is in 1.

Therefore, the force F in 7 directions when moving by θ from this state
recl, F rec2. Frec3 is Fre
c1= (sp/2) r ω2cos(θ
Frec2- (mp/
2) r ω2 CO3(θ-+-180)Fr
ec3-(■p/2)r ω2cos(θ+120
+-180), the Z-direction inertia force is balanced, and these 2
The eldest couple around the Y axis due to the force in the direction is (Jj/2) g+pr Q)2 L si
n θ---(2a') Also, in the Y direction, the polarity is angular because it rotates in the opposite direction to the crankshaft, but the inertial force is balanced in the same way, and the longitudinal bias around the Z axis due to this Y direction force is (Month/2)■p"ω21cosθ...(2b'
) Therefore, the inertia coupling in the longitudinal direction caused by the balancers 8a to 8C on the balancer axis side also occurs around the Y axis due to the Z direction and around the Z axis due to the Y direction, and the combined result is expressed by the above equation (2a'). (2b') gives the following equation.

(Month/2) lpr ω2 L (sin
θ + cos θ )...(4') By the way, the balancer on the balancer shaft side can also be separated and assembled in the same way as the crankshaft side in FIG. The mass of the equivalent balancer sow and the balance rust equivalent to the third cylinder is ■ρ/2
is multiplied by 5/2, and the one corresponding to the first cylinder is further advanced in phase by 30 degrees to be careful, and the one corresponding to the third cylinder is positioned with a 30 degree phase delay. This gives the same result as in Figure 5, and can be replaced by that.

As mentioned above, the balance of inertial force by the balancer on the balancer shaft side,
and the inertia couple in the longitudinal direction, and the result is equation (4'). Therefore, when this equation (4') is combined with the previous equation (4), it becomes zero, and from this, the longitudinal inertia couple due to the reciprocating mass generated on the crankshaft side and the mass of the counterweight that half-balances it is The balance will be balanced by the balancer on the balancer shaft side.

Next, we will explain the balance of the mass of the rotating parts of a three-cylinder engine.The configuration is the same as that shown in Fig. 2, and θ
The force acting on the first to third cylinders at the position where they have moved by F
cl, F c2. F c3 is as follows.

13-FC1=llCr ω2cos(θ+240)Fc
2-■Cr ω2 cos θFc3= acr
ω2cos(θ+120) As a result, the longitudinal couple around the Y axis due to the rotating mass is −Jjmcr ω2 1
．． sin θ ---(5a) The longitudinal eccentric force around the Z-axis becomes Jjmcr ω2 L CO3θ ---(5b), and similarly around the Y-axis in two directions and in the Y-direction.
This will occur around the axis, and when combined, it will look like this:

-mmcr oo 21- (sin θ -c
os θ ) --- (6) Next, a counterweight 6 that balances this rotating mass with each cylinder stone at a ratio of 1:1
To explain the balance by mass of a to 6c,
The configuration is the same as that shown in Figure 3, and each counterweight *ii
Force by, Trotl, Frot2. F rot3
becomes as follows.

Frot1=racr ω2 cos (θ+240
+180) Frot2=acr ω2 cos
(θ+180)F rot3= acrω2 cos
(θ+120 +180 > As a result, the eldest couple around the Y axis due to the Z direction is -14= Ijscr ω2 L sin θ −−
-(7a) The longitudinal couple around the two axes in the Y direction becomes -Moon-C'ω2LCO8θ...(1b),
The combination of the two results in the following.

Jimcr (t)2 L (sin θ −C
OS θ ) --(8) By the way, in the case of the rotating mass as well, as shown in Fig. 4, the mass is changed to -C (old/2
), and by advancing or delaying the phase by 30°, it is possible to separate and concentrate the counterweights on the first and third cylinders.

Thus, regarding the rotating mass, the combined whirling longitudinal couple around the Y- and Z-axes in equation (6) becomes zero by combining with the similar longitudinal couple in equation (8) due to the counterweight, and 21 becomes It will balance out.

The present invention is based on such a technical idea, and a specific embodiment thereof will be explained with reference to FIG. 7.As is clear from the above explanation, the engine has a reciprocating part and a rotating part for each cylinder. An inertial force and a couple are generated due to the mass of , which is of course possible. However, especially considering the fact that it is possible to balance the inertial force and couple only with the counterweight on the crankshaft side, it is possible to balance the mass of the rotating part with such characteristics. It is preferable to treat the balance separately from the mass of the reciprocating part, which can only be balanced in combination with the balancer shaft.

Therefore, in the crankshaft 1, first, counterweights 6a-1 and 6a-2 are applied to the mass of the rotating parts for each cylinder.
, 6b-1 and 611-a, 6cm1 and 6cm2 are provided on the opposite side of the crank pin of each crank arm as shown in Fig. 143. Next, as for the mass of the reciprocating part, as shown in FIG.
.

6σ-1 and 6σ-2 are similarly provided. In addition, in the balancer shaft 1, as mentioned above, the quality of the rotating parts of the rank shaft 1 is balanced separately, so only the unbalanced mass of the reciprocating part needs to be balanced, and therefore the Based on the technical idea shown in Figure 6, in all the first and third cylinders excluding the part corresponding to the second cylinder in the center, parts corresponding to the 211 crankshaft bearings 9a and 9b, 9c and 9d also serve as bearings. Two sets of balancers M-1 and td
-2, 4-1 and 8σ-2 are provided.

In such a configuration, when considering the balance on the crankshaft side, the counterweight 9'-1 for the mass of the forward 11 portion is
and m-2, sσ-1 and 6σ42 are separated and concentrated in two places, so the synthetic balance on each cylinder side is (mp
/2) by (month/2) and adjust the phase by 30°.If the pitch of each cylinder is L as in Fig. 2, then for the longitudinal eccentric force, (mp/2) (Jj /2) x2 L
= (Jj/2) spL should be generated.

Therefore, if the synthetic solder of the counterweights m-1 and m-2 is Mca', and the composite mass of the counterweights 6Bee1+8go-2 is MCC', considering the balance of the inertial force of the crankshaft bearing, M Holding Ca' -M CC', the resultant weight 6th position 1 for the Y axis of counterweight side -1 and 5tr-2 is L+x', counterweight 6 -
1 and 6, 217-, and the composite orthogonal position with respect to the Y axis is 11L+y', then M
ca' (1+ x' + L y') = (J3
/2) g+pl-, so the following general formula is obtained.

Mca' = Mc, q' = (f”r/2) Ip
l-/(2L+x'+v')
=-('la) Then the counterways 1-6a-1 and 6a-2, 6b-1 and 6 for the mass of the rotating part
For b-2, 6cm1 and 60-2, if the respective combined vR amounts are Vj ca, M cb, fvl cc, M
ca= M cb= M CC is held.

In addition, the counterweights 6b-1 and 6b-2 of the second cylinder
Counterweight 6 of the first cylinder with respect to the resultant center of gravity position of
If the combined center of gravity position of a-1 and 68-2 is L+x, and the combined center of gravity position of the third cylinder counterweight 6cm1 and 60-2 is [+y, then Mca (L+x) = Mcc (L+y), x =
Hold y.

Then, for the longitudinal couple, take out the Yh anti-acid component and get (Mca (L + X) 1 Mcc (1- + V)
't Co53018- = Jmscl- It is sufficient to satisfy the following general formula.

Mca=Mcb=Mcc=mcL/ (L +
x)...(9b) Therefore, the mass of each counterweight can be arbitrarily determined in relation to the position of the composite center of gravity, and in both cases the mass of the counterweight is 0 position w
The larger the values of x', y', x, and y are, the farther away they are, the smaller the mass will be. Here, to make it easier to understand, the first and third
By aligning the center of gravity of the cylinders, and by aligning the center of gravity of the second cylinder with that center, x' - y' = x - y =
If O, then the quality of the two counterweights in the first and third cylinders relative to the mass of the reciprocating part is (J'j/4)L, and the quality of the first to third cylinders relative to the mass of the rotating part is (J'j/4)L.
The quality of the counterweights at three locations on the cylinder is -C.

Further, in the first and third cylinders, both the masses of the reciprocating part and the rotating part are set separately at an angle of 30 degrees, but in reality, a single mass is provided by vector synthesis of these parts.

Next, in the balancer shaft 1, as is clear from the above explanation, it is related to the reciprocating part of the engine, and when it is separated and concentrated on the first and third cylinder sides, the mass of the reciprocating part of the rank shaft 1 is shown in F. Similarly, the quality layer on each cylinder side is (
sp/2) (J100/2) and adjust the phase by 30°, (-@I)/2) (J”i/2) X2 L
-(Ja/2) It is sufficient to generate a longitudinal couple of 1111 m.

Therefore, the balancer divided into two parts %-1 and af-2,8σ-
The combined masses Mba' and Mbc' of 1 and 8σ-2 are
Similarly, considering the balance of inertial force on the balancer axis, Mb
If a'=M bc' is maintained, and the combined center of gravity of each pair of balancers a(-t, 5a-a, 8σ-1 and -2 is l-+x'', 1+y'', then Mba' (1+ x″+L+V”),=
(V3/2)ml)L, it is sufficient to satisfy the following general formula.

Mba' = Mbc' = (month/2)
Garden pL/(21+ x″+ y″) ・・・ ([
l) Therefore, the mass of the balancer shaft 7 can also be arbitrarily determined in relation to the balancer position. Also,
Balancer &i − for balancer ah-1, aσ-1
2. The quality-proportion of W-2 does not need to be divided equally, and the outer balancer M-1, W! of each set is equal. As −x becomes heavier, the value of mutual composite weight 0 position 1fx y'' becomes larger,
The entire balancer mass is reduced.

In this way, on the crankshaft 1, the first and third cylinders (9a
) composition of formula jI eel counterweight side -1 and 26i9
2.6-1 and 6-2 are provided at a position 1 perpendicular to the crank arm 2b of the second cylinder, and a counterweight 6a-1 of the combined mass of formula (9b) is installed in the first to third cylinders. and 6
A-2, 6cm1 and 60-2 are provided on the opposite side of the crank pin of each crank arm. The balancer shaft 1r has bearings 9a and 9b on both outer sides of the first and third cylinders.

9C and 9d equivalent 4P and (phantom) composite mass balancer M
-1 and m-2, 8c'-1 and B-2, and the above-mentioned counterweights 6σ-1 and 6 when the second cylinder is at top dead center.
2, sa'-, and M-2, so that the inertial force due to the reciprocating part and the rotating part of the three-cylinder engine and the unbalanced couple are balanced.

So, huff”j M-1 and 8; i-2, at!-
1 and 2 - 21 - The bearings 9a and 9d are located at positions corresponding to the counterweights in each cylinder of the crankshaft 1, and are structured so as not to interfere with the counterweights, so the balancer shaft 1 Balancer 5r-1, atf-2, 8c
'-1, l1ld-2 can be placed close to the crankshaft 1 side in relation to only the counterweight without considering the existence of l1ld-2.

Furthermore, the combination 814 is provided in two sets of two pieces each.
Balanri U-1. P2. In Yodo-1 and Do-2, the outer balancers M-L and W-2 of each set are configured to serve as bearings in order to support the balancer shaft 1 well. Now, to explain in detail with reference to FIG.
0, and this shaft tube 20 connects to the bearing 9 through the metal 21.
It is assembled by fitting into the common shaft support 22 with a. The balancer 8σ-2 is constructed in exactly the same manner and is assembled to the common shaft support 24 with the bearing 9d, so that the balancer shaft 1 is connected to the bearing 9b for the balancer M-2, &'-1 of the inner 21!1. , 9c is a tree, but it is rotatably supported on both sides by the bearings 23 of the above-mentioned configuration in the balancers ah-1 and aσ-2 on both sides, and There is no need to install a bearing.

As is clear from the above description, according to the present invention, vibrations and the like are greatly reduced by balancing the power and torque in a three-cylinder engine. The mass of the reciprocating part and the rotating part are treated separately, and in particular the mass of the rotating part is balanced by the counterweight of the crankshaft cylinder, so the balance system as a whole will be simplified and clarified. Since the counterweight due to the reciprocating mass is spaced apart from each other only in the first and third cylinders on the crankshaft 1, the mass of the entire counterweight can be smaller than when it is provided for each cylinder. By adding generality to the installation of the counterweight and balancer, the degree of freedom in design increases. In the balancer shaft 7, the balancer & Since the bearings 9a, 9
By effectively utilizing the space in parts b, 9c, and 9d, it is possible to move the balancer shaft l closer to the crankshaft 1, which leads to a smaller size.In relation to the synthetic center of gravity, the balancer III itself is also smaller. It's over. Balancer is 2- in each group
Since it is divided into two parts, it is possible to add a predetermined mass sufficiently and easily using only these parts.

In addition, some of the balancers M-1 and ac-2 have built-in bearings and also serve as bearings for the balancer shaft 7, which reduces the bending moment generated on the balancer shaft 7 and reduces the balancer shaft diameter. It is possible to make it thinner in terms of strength and has high reliability. The bearings of the balancer shaft 7 are connected to the crankshaft bearings 9a, 9.
Providing it in the bearing equivalent part such as d is a rigid part of the engine, and can prevent problems caused by elastic vibration of the engine due to repeated acid type rotation.

Furthermore, even in the case where the balancer shaft 7 is partially submerged in oil due to the mounting position of the engine, the balancer M-4, W
-2 is housed in the entire circumferential shaft tube 20, so it is possible to prevent an increase in resistance due to oil agitation, oil spraying, etc. In this case, the inner baluns 9 M-2, M-s can also be provided with shaft tubes, which further enhances the above-mentioned effect.

A specific example of the balancer shaft installation will be explained with reference to FIG. 9. When the engine is installed under the loading platform using the R-R method as shown in the figure, the engine body 10 is restricted by the loading platform 16 and is placed in a vertical position. The air cleaner 11, the carburetor 12, the intake system of the intake pipe 13, the cooler compressor 14, the ACG 15, etc. are arranged on the engine main body 10 in this position. Therefore, the upper part of the engine body 10 is limited by the various auxiliary equipment mentioned above, so if the balancer shaft 7 is installed downward as shown in the figure,
The balancer shaft 1 is located below the crankshaft 1 and is partially submerged in oil, and in such a case, the effects of the present invention described above are exhibited.

[Brief explanation of the drawing]

1 to 6 are explanatory diagrams for explaining the present invention in detail,
Fig. 7 is a schematic diagram showing an embodiment of a balancer device for a three-cylinder engine according to the present invention, Fig. 8 is a sectional view showing a specific example of the main part, and Fig. 9 is a schematic diagram showing an embodiment of a balancer device for a three-cylinder engine according to the present invention. FIG. 3 is a side view showing a specific example of application. 1... Crank shaft, 2a, 2b, 2c... Crank arm, 6a-1+ 6a-2, ab-i, eb-2
, 6cm 1.6cm 2.6 siri, 6za-2゜sd
-1, sc'-2... Counter weight, 7... Balancer shaft, 呵-1, m-2, 酊-1, 酊-2... Balancer, 2o... Shaft tube, 21...・Metal, 22.24
... shaft support, 23... bearing. Patent applicant Fuji Heavy Industries Co., Ltd. Representative Patent Attorney Jundo Kobashi Patent Attorney Susumu Murai 261

Claims (1)

[Claims] The first and third cylinders of one crankshaft, in which crank arms are sequentially arranged at equal intervals of 120 degrees, have counter weights for the engine's 11 cylinders and rotating mass, and the second cylinder has a counter weight for the engine's rotating mass. By installing one balancer shaft that has only a weight and rotates at the same speed in the opposite direction to the crankshaft, two bearings each on the first and third cylinder sides of the crankshaft are installed on the balancer shaft. To a considerable extent,
The GJ has two sets of balancers divided into two parts, and the outer one of each set of the balancers is also used as a bearing.
3-cylinder engine balancer device.