JPS5837351A - Balancer for 3-cylinder engine - Google Patents

Abstract

PURPOSE:To contrive the weight reduction and miniaturization of a balancer by using all balancers provided at 3 places corresponding to the crankshafts of the first, second, and third cylinders of the balancer shaft as bearings concurrently. CONSTITUTION:In the first cylinder of a crankshaft 1, counter weights 6a'-1 and 6a'-2 are provided at two places corresponding to both crank arms 2a-1 and 2a-2, and in the third cylinder, counter weights 6c'-1 and 6c'-2 are provided at two places corresponding to both crank arms 2c-1 and 2c-2. Also, in the balancer shaft 7 provided in such a way as to turn it in the opposite direction at the same speed as the crankshaft 1, balancers 8a-8c are provided in half-balanced manner at places corresponding to crankshafts 9a-9c, and all of the balancers 8a-8c are designed to be used as bearings 23 concurrently.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a three-cylinder engine for an automobile, in which a counterweight is provided on the crankshaft itself, and a balancer shaft is further provided that rotates in the opposite direction at the same speed as the crankshaft. The present invention also relates to a balancer device that balances the first-order inertia force due to the rotating mass 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.

In each cylinder, there is an inertia force due to the reciprocating mass and a rotating mass.The inertia force due to the rotating mass can be balanced out by installing a counterweight on the opposite side of the crank arm, and the inertia force due to the reciprocating mass Φ is due to the rotating mass. It is possible to half-balance at the same position as the case, and balance the remaining part with a balancer shaft that rotates at the same speed as the crankshaft but in the opposite direction. By the way, in the case of a three-cylinder engine, even though the inertia forces of each cylinder are balanced as described above and the inertia couple around the X axis is also balanced, an inertia couple occurs in the longitudinal direction, and it is necessary to balance this inertia couple. In order to remove the problem, conventionally, for example, the crankshaft counterweight has a specific split structure as in Japanese Patent Application Laid-open No. 55-6035, or Japanese Patent Publication No. 55-6035
As disclosed in Japanese Patent No. 4-2333, an inertia couple having 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 considered good 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 middle second cylinder, so the length of the crankshaft is affected by this. The directional inertia couple must be taken into account, and this has a large effect on engine vibration. On the other hand, the longitudinal couple 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 changed depending on the distance between the balun and J. By specifying the mounting position of the balancer, it is very advantageous in terms of the structure of the balancer shaft itself, the degree of freedom in design, the arrangement relative to the crankshaft, etc.

In view of these circumstances, the present invention achieves balance against inertia force and inertia couple by using a counterweight of the crankshaft and a balancer of the balancer shaft, brings the balancer shaft closer to the crankshaft side, makes it lighter and smaller, and furthermore The object of the present invention is to provide a balancer device for a three-cylinder engine which is advantageous for supporting bearings and can prevent inconveniences caused when the balancer shaft is immersed in oil. An example will be explained in detail. First, in Fig. 1, the balance system per cylinder will be explained. In the figure, numeral 1 is the crankshaft, 2 is the crank arm sequentially arranged at equal intervals of 120°, and 3 is the crankshaft. , 4 is a connecting rod, 5 is a piston, and a counterweight 6 is installed on the extension line of the crank arm 2 on the opposite side from the crank bin 3 to balance the entire inertial force due to the rotating mass and half the inertial force due to the reciprocating mass. In addition, one balancer shaft 7 is provided that rotates in the opposite direction at the same speed as the crankshaft 1, and a balancer 8 is provided that half-balances the remaining part of the inertial force due to the reciprocating mass. When the arm 2 is positioned clockwise by θ from the top of the Z-axis, the balancer 8 of the balancer shaft 7 is positioned counterclockwise by the same amount θ from the bottom of the Z-axis.Here, the inertia of the reciprocating portion is expressed as mp, To make the explanation easier to understand, if the equivalent inertial mass of the rotating part crankbin 3 is written as +nc, then the mass of the counterweight 6 on the crankshaft side is t
For one return Mljmp, it is necessary to half balance, so mp/2, and for the rotating mass mc, it rotates in the same direction as the crankshaft 1, so it is possible to balance all of it, resulting in mc, and the total is ( mp/2) ImC Domuru. Further, the mass of the balancer 8 on the balancer shaft side is the remainder of the above-mentioned reciprocating mass and becomes mp/2.

By doing this, the inertial forces of the reciprocating portion and the rotating portion in the 7°Yh direction are balanced. Therefore, in a 3-cylinder engine, if a counterweight 6 and a balancer 8 of the above-mentioned masses are attached at positions corresponding to each cylinder, the total force and sinker weight on the crankshaft side is 3 ((ml)/ 2)+mc)・The total mass of the balancer on the balancer shaft side is (3/2.), mp.

Next, the balance due to the mass of the reciprocating part in a three-cylinder engine will be explained with reference to Figure 2.
or the third cylinder is indicated by a suffix a or C,
Also, the second cylinder is at top dead center, and the first cylinder is at the top dead center.
The third cylinder is rotated by 40 degrees, and the third cylinder is rotated by 120 degrees.

Therefore, when the cylinder moves by θ from this state, the excitation force Fp1 of the first cylinder, the excitation force Fp2 of the No. 1 cylinder, and the excitation force Fp3 of the third cylinder are as follows.

F111=lllpr (7J2 CO3(θ+240
)Fl)2=ml)r ω2cosθ Fp3=Illpr ω2cos (θ+120)
Therefore, the total inertial force is balanced by Fp1+j''l)2+Fp3=0.

In addition, the inertia couple in the longitudinal direction of the crankshaft is viewed from a point P which is a distance MS apart from the first cylinder in order to have a -membrane property, and if the pitch of each cylinder is L, then Fpl-8 + "p2 ( S+1> 10F+13 (S+21
).

That is, Fpl-S+ Fp2(S+L) +Fp3(S+2.
1-)=-1'''imprω21 sinθ-・-(1
), a one-handed couple around the Y-axis is generated by the reciprocating inner gutter which is the Z-direction entrance E.

To explain the balance of the counterweights 6a, '6b, and 6c, which are half-balanced for each cylinder in FIG. When the counterweight of each cylinder is 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 seven directions when moving by θ from this state, the force due to each counterweight mass F recl, F rec2.1
``rec3 or something like this.

"rcc+= (mp/2) r ω 2
cos (θ −to 240 −1−180
) Frec2 = (IRp/2) r ω2CO
5 (θ+180) Frec3- (mp/2) r
ω2 cos (θ4-120 + 180 > Therefore, the inertia force in the 7 directions is F recli - F rec2 + F rec3-
It becomes 0 and balances out.

On the other hand, if the inertia couple in the longitudinal direction due to such a force in the Z direction is obtained in the same manner as above, it is obtained as F recl ・S”+ F rec2 (3+ l
) + l: rec3 (S 12m> = (5/2) mpr ω2 1-sin
θ---(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 seven directions 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. Become.

-(F3/2) mpr ω21 cosθ, --(
2b) That is, a longitudinal couple around the Z axis is generated due to the force in the Y direction.

Above, the counterweight 6a to 6G 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.

<f”i/2 ) 1 lipr ω21-sin θ-(
J'i/2) mpr×ω2LCO3θ = (E/2) ml)rω21-'(sinθ
-cosθ)...(3) By the way, the above-mentioned counterway l-4 on the crankshaft side
, 1. In addition to providing each cylinder separately, it is also possible to separately set the cylinders in the first and third cylinders on both sides of the cylinder, excluding the second cylinder in the center. explain.

If you look at the result (omitting the progress in progress), the first and third
Cylinder counterweights 6a and 6c are <5/2)
(mp/2), the first cylinder's counterweight 6 is at a position further 30' phase advanced from the position 180' phase advanced from the crank arm 2a, and the third cylinder's counterweight 6σ is from crank arm 2C 180
``It is provided at a position that is 30 degrees behind in phase from the position where the phase is advanced. That is, both counter seats 6a' and 6c are located at positions 180 degrees opposite to the crankshaft 1 and at right angles to the central crank arm 2b.

In this case as well, it is θ from the state shown in the figure (the force due to the mass of each counterweight in 7 directions when it moves is 1" ree
l', Frec3' is Frec+'-'(Jj
/2 ) (mp/2) r ω2X cos (
D + 240 + 180 + 30) Frec3' =
(jj/2) (In+)/2) r ω2x
cos(θ+120 +180.30>, and the Z-direction inertial force becomes ``rec1' + Frec3', = Q, which naturally balances out.

Next, the longitudinal inertia couple due to the forces in these seven directions is Frecl' ・S+Frec, 3' (S+21
)=(JT/2) mpr ω21−sinθ, which agrees with equation (2a).

The inertia forces are also balanced in the Y direction, and the longitudinal inertia couple due to the force in the Y direction matches equation (2b).

For this reason, three counterweights on the crankshaft side are provided for each cylinder, or one counterweight is provided for each cylinder. It is understood that even if two cylinders are provided in the third cylinder, the inertia forces are balanced and the inertia couple in the longitudinal direction becomes the same.

Above, we have explained the balance of inertia force due to the reciprocating mass and counterweight on the crankshaft, and the longitudinal inertia couple, that is, the whirling, but now the longitudinal couple of equations (1) and (3) remain. , by synthesizing this, −Jjmpr oo2 L sin θ+ (month/2) mpr ω2XL(sin θ−c
os θ) = −(fi/2)mpr ω21− (si
n θ + COS θ) (4). Therefore, how to balance such a longitudinal couple on the balancer shaft side will be explained with reference to FIG. first,
The balancer shaft 1 also has a balancer 8a corresponding to each cylinder.
, 8b, and 8c, the mass of each balancer 8a to 8C is mp/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 balance 18b corresponding to the second cylinder is at the opposite position on the bottom dead center side, and the balancer 18b corresponding to the first cylinder is at the opposite position.
a is further 180 degrees from the position where the phase has advanced 240 degrees counterclockwise.
The balancer 8C corresponding to the third cylinder is located at a position shifted by 120 degrees counterclockwise and further advanced in phase by 180 degrees.

If you move by θ from this state, the 7-direction NoJ
Frecl, Frec2. F
rec3 is trecl-(mp/2) r
oo2 cos (θ+240 +180) F r
ec2= (n+p/2) rω2cos(θ+18
0) Frec3= (mp/2) r ω2
cos , (θ+120 +180 >, the Z-direction inertial force is balanced, and the longitudinal couple around the Y-axis due to this Z-direction force is (JM/2) mpr to21 sinθ---(
2a') Also, in the Y direction, the polarity becomes negative because it rotates in the opposite direction to the crankshaft, but the inertial force is balanced in the same way, and the longitudinal couple around the Z axis due to this force in the Y direction is (Jj /2
) mprω2 L CO3θ --- (2b') Therefore, the inertial couple in the longitudinal direction generated by the balancers 8a to 8c on the balancer axis side also occurs around the Y axis in two directions and around the Z axis in the Y direction, and the resultant The result is as follows using equations (2a') and (2b') above.

(J”j/2) mpr Q)2 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 balancer U and balancer 8 corresponding to the third cylinder is mp/
2 multiplied by 5/2, the one corresponding to the first cylinder is located further 30' in phase, and the one corresponding to the third cylinder is located 11ffi in 30° phase. This results in the same binding as the one in Figure 5, which can be replaced.

As mentioned above, the balance of inertia force by the balancer on the balancer shaft side,
This is an explanation of the inertial couple in the eldest 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 reciprocating mass and deflection generated on the crankshaft side are half-balanced by the use of a counterweight. The inertial couple is balanced by the balancer on the balancer shaft side.

Next, we will explain the balance depending on the quality of the rotating parts of a three-cylinder engine.The configuration is the same as that shown in Figure 2, and θ
The force acting on the 1st to 3rd cylinders at the position where they have moved, Fc
l, Fc2. Fc3 is configured as follows.

Fcl=mcr ω2 cos (θ + 2
40) EC2;=IllCrω2CO8θ Fc3=rncr ω2 cos (θ+120
) As a result, the longitudinal couple around the Y axis due to the rotating mass is
-5mcr ω2 Lsinθ ... (5a) The longitudinal couple around the Z axis becomes J'jmcr ω2 Lcosθ --- (5b) Similarly, around the Y axis in 7 directions and Z in the Y direction
This will occur around the axis, and when combined, it will look like this:

-j'jmcr w2 L (sin θ-cos
θ)---(6) Next, this rotating mass is 1 for each cylinder.
:1 counter weight 6a to 6
To explain the balance by mass of c, it is similar to the configuration shown in FIG. 3, and each counterweight 'fIm, Frotl, Frot2. F rot3 is as follows.

Frot1=mcr ω2 cos (θ+240
+180) Frot2=llllcr (c120O3
(θ+180) Frot3=tacr to2 cos
(θ+120 +180 > As a result, the longitudinal couple around the Y axis due to the Z direction is Jnicr oo2 Ls
inθ --- (7a) The longitudinal couple around the Z axis due to the Y direction is -Hmcr a) 2 1- cos θ --
-(7b), and the combination of the two results in the following swing.

mracr rn2L (sinθ-cosθ) --
(8) By the way, in the case of such a rotating mass, as shown in Fig. 4, counterweights can be applied to the first and third cylinders by multiplying the mass mc by (Jj/2) and advancing or retarding the phase by 30°. It is possible to separate and concentrate.

hs (For the rotating mass, the Y axis and Z of equation (5)
The resultant whirling longitudinal couple around the axis becomes zero by combining a'-n' with the similar primordial couple of equation (8) by Karantau 1 degree, and the two become balanced. °.

The present invention is based on such a technical idea, and a specific embodiment thereof will be explained with reference to FIG. 7. In the crankshaft 1, as shown in FIG. In this case, in order to increase the degree of freedom in removing weights (-jG), in the first cylinder there are Counterweight 6za-1, 6za-2
However, the crank arm '2cm1, 2c for the 3rd cylinder as well.
Counterweights 6σ-1, 5 at two locations corresponding to m2
d-2 is provided. Further, in the balancer shaft 1, as shown in FIG. 5, balancers 8a, 8b, and 8c are installed in all the cylinder-corresponding parts of the first to third cylinders, especially in the parts corresponding to the crankshaft bearings. .

Two counterweight sides of crankshaft 1 - 1°6 points -
The proportions of the two masses do not necessarily have to be equal, and can be arbitrarily determined by GF, depending on the composite center of gravity &m, and the other two counterweights ec'-x.

The same applies to 6d-2. In addition, when separating and concentrating the quality of the reciprocating part and rotating part of the engine on the first and third cylinders, as is clear from the above explanation, the synthetic quality of each cylinder side ((( death/2) +i'c) (and/2)
Assuming that the pitch of each cylinder is L as in Fig. 2, then for the eldest couple, ((mp/2) +sc) (IN/'2) 21
=<Old/2) IIIIL -14jlCL should be generated.

Therefore, the combined mass of the counterweights 6a-1 and eza-2 is MCa', counterweight 66-L, ec'
-2 composite mass is MCC,', then crankshaft 1
Considering the balance of the inertial forces above, M ca' = M
It is necessary to hold CC'.

Then, the combined center of gravity position of the counterweights 6a-1 and 6f-2 is l+x1 counterweight 6σ-1+6c'
-2's composite center of gravity is L-11, then Mca'(-Mcc') x (1-+x +
I-+y) = (J'j/2) mpL +4jm
As long as cL is satisfied, Mca' = MCC' = '('(Jj/2) mp
L −NMn+cl−, )/(2L+x +y)
・!・(9)

Here x=y=o, i.e. counterway I-6a −1
.

If the combined center of gravity positions of 6i-2, 6σ-1 and 6σ-2 are made to match the pitch of each cylinder, the quality IMca', 1
ylcc' is (Mon/4) 1111 (Mon/2) Il
It becomes IC. Also, since x and y can be determined in one step,
The larger the value and the farther apart the center of gravity is, the more the mass Mca
', M (C' can be small.

Next, in balancer axis 1, as is clear from the above explanation, i
It is only the mass of the reciprocating part of the engine, and for each cylinder equivalent -
It is sufficient to perform half balance with a mass of p/2. Therefore,
The respective masses of balancers 8a, ab, and 8c are Mba and M
bt+, Mbc, and the center of gravity position of the balancer sa, 80 with respect to the central balancer 8b is x/, y/
Then, considering the balance of inertial force on the balancer axis, maintain Mba=Mbb=Mbc It is sufficient to take the Y-direction component of 8α and satisfy the following equation.

(Mba(Lx') +Mbc(L+y')
) cos30= (IN/2) IpL, that is, Mba=Mbb=Mbc= (wpL/2) (L
+ x') ... (Therefore, the center balancer 8b does not need to be aligned with the center of the second cylinder, but the positions of the balancers should be spaced apart from each other so that x'
The larger the value of , the smaller the balancer mass. On the other hand, the entire balancer 8a (old) and 8C is moved to the first cylinder side as shown in Figures H and B, and the bearing Qa is installed.

! If you place it in the parts corresponding to lb and 9c, or conversely move it to the third cylinder side and place it in the part corresponding to bearings 9b, 9G, 9 (I), the crankshaft bearing part of the balancer 8a, 8b, 8c Effective use of space has been achieved, ■
Move the balancer shaft 7 closer to the crankshaft 1.

From this, in the crankshaft 1, the counter eights 6, f -1, 6a'-a on the first cylinder side and the counter eights 60'-1, 6σ-2 on the third cylinder side are considered to be the composite center of gravity. According to the relationship, both masses satisfy equation (9), the position of the counterweight 68'-1°ea-2 is on the opposite side to the crank pin, the phase is advanced by 30°, and the counterweight 6σ-1, 6
C', -2 position is on the opposite side from the crank pin and the phase is 30
4 degrees and are both at a position 4 perpendicular to the crank arm 2b of the second cylinder.

In the balancer shaft 7, balancers 8a, 8b, and 8c are connected to respective cylinder-corresponding parts such as crankshaft bearings 9a, 9b, and Qc.
At the position of the corresponding part, equation (10) is satisfied and there is a half balance with J mass, and as a result, the inertial force and couple due to the mass of the J1 return part and the rotating part of the 3-cylinder J engine are balanced.

Furthermore, the balancers 8a, 8b, and 8c are all configured to serve as bearings, and to explain in detail with reference to FIG. Then, this shaft tube 20 is fitted into a shaft support 22 common to the bearing 9a through a metal 21, and is moved relative to the bearing 9a. The balancers 8b and 8c are also configured in exactly the same way, with a shaft support 24 common to the bearing 9b and a shaft support 2 common to the bearing 9C.
5, and as a result, the balancer shaft 1 is rotatably supported at three locations at both ends and in the middle by bearings 23 containing these balancers 8a, 8b, and 8c, and no other bearings are installed. () can be omitted.

In addition, balancers 8a, 8b, and 8c, which also serve as bearings, serve as counterweights 6a-1, s for each cylinder of the crankshaft 1.

The balancers 8a to 8c are arranged in the bearing-corresponding parts shifted from the positions of 6c'-1 and 6-2, and are structured so as not to interfere with the counterweights having a large turning radius.
It is possible to arrange the balancer shaft 7 itself close to the crankshaft 1 side within a range where it does not interfere with the counterweight without considering the balancer shaft 7 itself.

In addition, although the example shows the case where the balancers 8a to 8c are moved to the first cylinder side, it is also possible to move them to the third cylinder side and arrange them at the corresponding portions of the crankshaft bearings 9b, 9c, and gd. Of course, in this case, the effect of shortening the axial length of the balancer shaft 7 as in the embodiment cannot be achieved.

Since it is balanced, there is very little vibration.

Crankshaft bearings 9a to 9c on balancer shaft 1.

Also, balancers 8a and 8b are installed in the parts corresponding to 90 and 9d.
, 8c are installed [)C, space can be used effectively, and the installation of the balancer 11 is advantageous, and the balancer shaft 7
This makes it possible to bring the engine closer to the crankshaft 1 side, contributing to miniaturization.

Since all the balancers 8a, 8b, and 8c have a built-in bearing structure and also serve as bearings for the balancer shaft 7, the bending moment generated on the balancer 4J shaft 7 is significantly reduced, and the balancer (1 It is possible to reduce the shaft diameter in terms of strength and reliability is high. Providing the bearings of the balancer shaft 7 in the parts corresponding to the bearings of the crankshaft bearings 9a, 9b, 9c, and 9d is a location with high rigidity for the engine. ,
Inconveniences caused by elastic vibration of the engine due to repeated loads can be prevented.

Furthermore, even if the balancer shaft 7 is partially submerged in oil due to the mounting position of the engine, the balancers 8a and 8b
, 8c are accommodated in the entire circumferential shaft tube 20, thereby preventing an increase in resistance due to oil agitation, oil spouting, etc.

A specific example of the balancer shaft mounting f1 will be explained with reference to FIG.
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 top of the engine body 10 in this position. Ru. Therefore, the upper part of the engine body 1o is limited by the above-mentioned ridge auxiliary machines, and when the balancer shaft 7 is installed downward as shown in the figure, the balancer shaft 7 (a) is attached to the crankshaft 1 and the lower part (a) l)
If <=, the part will be soaked in the oil, and in such a case, the effects of the present invention described in 1-2 will be exhibited.

[Brief explanation of drawings]

] Figures 1 to 6 are explanatory diagrams explaining the present invention in detail, Figure 7 is a schematic diagram of an embodiment of a balancer device for a 63-cylinder engine according to the present invention, and Figure 8 is a specific example of the eastern part. FIG. 9 is a side view showing a specific example of the present invention applied to an automatic cow.
2a-1, 2a-2. 2cm1, 2cm2...Crank arm, 6,611
．． 6za-2, 6C'-□+ec-2...counter r
Light, 7... Balancer axis, 8°+la, 8b, 8
cm... Balancer, 9a, 9b, 9c, 9d...
・Bearing, 20... Shaft tube, 21... Metal, 22.2
4.25... shaft support, 23... bearing.

Claims (1)

[Claims] A predetermined mass is placed at a position perpendicular to the crank arm of the second cylinder on the opposite side of the crank pin of the crank arm of the first and third cylinders on the crankshaft in which the crank arms are sequentially arranged at equal intervals of 120 degrees. A counterweight is installed,
Rotating in the opposite direction at the same speed with respect to the above crankshaft 1
A main balancer shaft is provided, and balancers having a predetermined mass are provided at three locations on the balancer shaft corresponding to the crankshaft bearings of the first to third cylinders so as to be half-balanced;
A balancer device for a three-cylinder engine characterized in that all of the balancers also serve as bearings.