JPS5877949A - Balancer for 3-cylinder engine - Google Patents

Abstract

PURPOSE:To make an engine smaller by arranging counter weights uniformly on the first-third cylinders of a crank shaft while weights are provided at parts corresponding to the first-third cylinders of a balancer shaft turning at the same speed as the crank shaft but opposite in the direction. CONSTITUTION:Counter weights 6a-1, 6a-2-6c-1, 6c-2 are provided on a crank shaft opposite to crank pins of respective crank arms to receive a total mass of each reciprocating and rotating part of cylinders. Balancers 8a-8c are provided at parts corresponding to the first-third cylinders of a balancer shaft 7 so arranged as to turn at the same speed as the crank shaft but opposite in the direction to receive mass attributed to reciprocating motion. The combined mass Mca and Mcc are equal each.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a three-cylinder automobile engine with a counterweight on the crankshaft itself, and a balancer shaft 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 inertia force due to the rotating mass and the primary inertia couple in the longitudinal direction of the crankshaft.

In each cylinder, there is an inertial force due to the reciprocating mass layer and the rotating mass, and the inertial force due to the rotating mass can be balanced by providing a counterweight on the opposite side of the crank arm, and the inertial force due to the reciprocating mass layer is Balance half of it at the same position as in the case of quality - (half balance)
, the remaining part can be balanced by 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 if the inertia forces of each cylinder are balanced as described above, an inertia couple occurs in the longitudinal direction. 6
The crankshaft counterweight has a specific separation structure as in Publication No. 035, or Japanese Patent Publication No. 54-2333.
As disclosed in Japanese Patent No. 3, there is a system in which 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 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 inertial couple generated in the crankshaft system due to this inertial force can be balanced by a balancer weight (hereinafter simply referred to as balancer) on the balancer shaft, but in this case, even if the couple is constant, it will vary depending on the distance between the balancers. Since the mass of the balancer can be changed 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 aims to balance the inertia force and the inertia couple by using the counterweight of the crankshaft and the balancer of the balancer shaft, and also to bring the balancer shaft closer to the crankshaft side and to reduce the size of the light chain. Another object of the present invention is to provide a balancer device for a three-cylinder engine that can deal with problems caused by the balancer shaft support and the balancer when it 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 of inertia force per cylinder in Fig. 1, reference numeral 1 is the crankshaft;
2 are crank arms sequentially arranged at equal intervals of 120°, 3
is a crank bin, 4 is a connecting rod, and 5 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 1 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 rest of the inertial force due to the reciprocating 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, if the inertial mass of the reciprocating part is -p1 and the equivalent inertial mass of the crank bin 3 of the rotating part is 10 to make the explanation easier to understand, then the equivalent mass of the counterweight 6 on the crankshaft side is relative to the reciprocating mass -p. Since it is only necessary to half-balance the rotational mass -G, it rotates in the same direction as the crankshaft 1, so it becomes 10, and the total is (mp /'2) +wc
becomes. Moreover, the equivalent quality of the balancer 8 on the balancer shaft side is the remainder of the above-mentioned reciprocating mass, which becomes p/2.

By doing this, the primary inertial forces in the 2°Y direction of the reciprocating portion and the rotating portion are both balanced.

Therefore, in a 3-cylinder engine, if a counterweight 6 and a balancer 8 of the above-mentioned masses are attached to the positions corresponding to each cylinder, the total mass of the counterweights on the crankshaft side will be 3 ((-pi2)+*C). , the total mass of the balancer on the balancer shaft side is (3/2) sp.

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 engine has rotated 40'', and the third cylinder has rotated 120 degrees.

Therefore, if the first cylinder moves by θ from this state,
The outrage force Fpl, the primary inertial force Fp2 of the second cylinder, and the primary inertial force Fp3 of the third cylinder are as follows.

F pi-mpr ω2cos(θ + 240″
) Fp2-apr ω2 cosθ Fp3-apr oo2 cos (θ+120'
) Therefore, the total inertial force is balanced by F pl+ F p2+ F l)3-0.

The sum of the moments of inertia around any point P can be regarded as a couple only when the inertia forces are balanced. If the inertial forces are not balanced, the sum of the moments due to the inertial forces around any point is the moment around that point due to the couple and unbalanced inertial forces, and the value differs depending on which point is taken as the reference point.

Therefore, if the inertial forces are unbalanced, even if the couple is O, the sum of the moments due to the inertial forces will not be O, and the equilibrium of the couple cannot be determined.

Even if the inertial force is unbalanced, the equilibrium of the couple can be determined by using the center of the clutch system (the center of the center cylinder for odd-numbered cylinders, the center bearing for Confucian cylinders) in the case of an in-line engine with an equal internal arrangement. This is the case.

At this time, even if there is an unbalanced force, the sum of moments due to the unbalanced force is 0, so the sum of moments due to inertial force = accidental force.

As is clear from the above, the method using an arbitrary point P as a reference is not very general in explaining coincidences. In the case of a 3-cylinder E/G, it is more general to use the center of the #2 cylinder as a reference, and the equation is also simpler.

In addition, since the inertial forces in the longitudinal direction of the crankshaft are balanced, in order to maintain generality, we will look at the inertia couple from the point P, which is a distance S apart from the first cylinder, and let the pitch of each cylinder be L. , FEll・S+Fp2(S+1)+Fp3(8+21)
It is indicated by.

That is, F91 life S + FE12 (S 10 L) + FE13 (S + 2
L)--mmpr oo2 LsInθ ◆・-(1)
As a result, longitudinal bias around the Y axis is generated due to the reciprocating mass which is a bidirectional load.

To explain the balance by mass of the counterweights 6a, eb, 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, Ba ha crank arms 2a, 2b.

It is located at a position 180° in phase with respect to 2C. Therefore, in the two directions when moving by θ from this state, the inertia forces Frec1, FreC2, F due to the quality of each counterweight
rec3 becomes as follows.

Frecl-(*p/2) r ω2 cos (
θ+240' + 180')1': rec2-
(e+p/2) r oo2 cos (θ+ 1
80' ) Frec3- (sp/2) r ω2
cos (θ+120' + 180°) Therefore, 2
The inertia forces in the directions are balanced as Frecl+Frec2+Frec3-0.

On the other hand, if the inertia couple in the longitudinal direction due to such a force in the Z direction is found in the same manner as above, Frecl-S+Frec2(3+l-) +Frec
3(S12L) −(IN/2) gipr ω2 L sin θ−
--(2a), and similarly a longitudinal bias force around the Y axis is generated.

In addition, the counterweights 6a, eb, and 6c have a component 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. .

-(Jj/2) Peng p'ω'Lcos θ
・ ・ φ (2b) That is, a longitudinal couple around two axes is generated due to the force in the Y direction.

Above, we have explained the balance of the inertial force due to the reciprocating mass and counterweight on the crankshaft, and the inertia couple in the direction of the arm's force, that is, the whirling.
By composing the couple around Y@ from the formula, -Jjspr ω21-sinθ+(Jj/2) g
ipr ω2X L sin θ = −(IN/2) spr ω2 1-sin θ
---(3). Therefore, how to balance such a longitudinal couple on the balancer shaft side will be explained with reference to FIG. 4. First, in the balancer shaft 7, if the inertia force due to the reciprocating mass is half-balanced by the balancers 8a, 8b, and 8c corresponding to each cylinder, the mass of each balancer 8a to 8C is -p with respect to the reciprocating mass on the crankshaft side. /2
It is. 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 counterclockwise 240 degrees.
The balancer 8C corresponding to the third cylinder is located at a position further shifted by 180° from the position where the 0 phase is advanced, and the balancer 8C corresponding to the third cylinder is located at a position where the phase is further advanced by 180° from the position 1200 in the counterclockwise direction.

Therefore, the force F in two directions when moving by θ from this state
real, Frec2. Dry rec3 is F rec
1= (sp/2) r a>2 cos (θ+2
40' + 180' ) Frec2- (iip/
2) r ω2 cos (θ + 18
0' ) Frec3- (sp/2) r
ω2 cos (θ +120' + 180'
), the two-direction inertia forces are balanced, and the longitudinal eccentric force around the Y-axis due to these two-direction forces is (IN/2') -pr ω2 Lsin θ
---(2a') Also, in the Y direction, the polarity is negative because it rotates in the opposite direction to the crankshaft, but the inertial force is similarly balanced at b, and the longitudinal eccentric force around Z due to this Y direction force is , (J
j/2) mpr ω2 Lcosθ−・−(2b'
).

By the way, the balancer on the balancer shaft side is not only provided for each cylinder, but also for the first cylinder on both sides except for the second cylinder in the center.
It is also possible to provide them separately and collectively in a portion corresponding to the third cylinder, and this case will be explained with reference to FIG. To state the results without going into details, the mass of the balancer shaft side parts corresponding to the first and third cylinders is (sp/2) and (Jj/2
), and the balancer d of the part corresponding to the first cylinder
is located 30' phase ahead of the half-balanced one mentioned above, and the balancer for the part corresponding to the 3rd cylinder is located 30' in phase.
°The position is delayed in phase. That is, both balancers U.

The cylinder is provided at a position perpendicular to the crank arm 2b of the second cylinder in the center.

In this case, 2 when moving by θ from the state shown in the figure.
The force in the direction Freal' , , F rec3' is F
rec1' - (ff/2), (sp/2) r
ω2xcos(θ+240°+180°+30°)1:
rec3'-(JN/2) (Ip/2
) rω2xcos(θ+120”+1
80'''-30'), and this Z-direction inertial force is balanced by Fre01'+Frec3'=0.

Then, the longitudinal inertia force due to this Z-direction force is F real' - S + F rec3' (S
+21 ) = (ff/2) aprω2 L
sin θ, which agrees with equation (2a').

On the other hand, in the Y direction, the polarity becomes negative and the COS becomes sin, the inertial force is balanced, and the longitudinal inertia couple due to the force in the Y direction matches equation (2a').

From this, two balancers 8af and W! provided in the portions corresponding to the first and third cylinders are used. The inertial force is balanced even if the inertial force is moved by
”) and (2b'), the result is the same as in the half-balance case, and we can learn from it.

As mentioned above, the balance of inertia force by the balancer on the balancer shaft side,
This is an explanation of the inertia couple in the longitudinal direction, and the results are expressed as equation (2a') around the Y axis and equation (2b) around the Z axis.
'). Therefore, this formula (2a'), (2
b') is combined with the above equations (3) and (2b), it becomes zero around the Y axis and around the two axes, and from this, the reciprocating mass generated on the crankshaft side and the mass of the counterweight that half balances it. The inertia couple in the longitudinal direction due to this 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 1st to 3rd cylinders at the position where they have moved by FC
I, Fe2. Fe2 becomes as follows.

Fc1=-cr ω2 cos (θ + 2
40') Fc2=acr ω2 cosθ Fc3= mcrω2 cos (θ+120'
) As a result, the longitudinal eccentric force around the Y axis due to the rotating mass is -
JNscr ω2 1sin θ ---, (
4a) The longitudinal eccentric force around the Z axis is 5-C "ω2 Lcos θ ・ ・ ・
It becomes (4b).

Next, the balance by the mass of the counterweights 6a to 6G, which balances this rotating mass at a ratio of 1:1 for each cylinder, will be explained.The configuration is the same as that of FIG. 3,
The force due to each counterweight mass, F rotl, F
rot2. F rot3 is as follows.

Frotl-mar ω2 cos (θ +
240' + 180') Frot2=w
cr ω2 008 (θ + 180”)
Frot3=mcr ω2 cos (θ +
120° + 180°) As a result, the longitudinal eccentric force around the Y axis in two directions is JNscr ω2 1sin
θ ---(5a) The longitudinal bias around the two axes in the Y direction is -finer ω2 Laosθ ---(5b).

Thus for the rotating mass (4a), (4b)
The sum of the couple components around the Y-axis and Z-axis expressed by the equations and the couple components of equations (Sa) and (5b) due to the counterweight becomes zero, and the two are balanced.

The present invention is based on such a technical idea, and a specific embodiment thereof will be explained with reference to FIG. Therefore, in the crankshaft 1, the counterweights 6a-1, 6a-a+6b-1, and 6b-2 for the mass of the reciprocating and rotating parts for each cylinder are combined.
60-1 and 6cm2 are provided on the opposite side of the crank pin of each crank arm as shown in FIG. As shown in FIG. 4, the balancer shaft 7 is provided with balancers 8a, 8b, and 8c for all cylinders corresponding to the first, second, and third cylinders, respectively, as shown in FIG.

In such a configuration, first considering the balance on the crankshaft side, since each cylinder has a counterweight for the combined mass of the reciprocating and rotating parts, 6a-2,
The respective combined masses Mca, Mcb, and Mcc of the counterweights 6b-1 and 6b-2 of the second cylinder and the counterweights 6C-1 and 6G-2 of the third cylinder take into account the balance of inertial force on the crankshaft. Then, Mca=Mcb=
It is sufficient to hold Mcc and gic+ (1/2) so. By the way, the synthesis of the counterweights in each cylinder - the central position does not need to coincide with the center of each cylinder, and the pitch of each cylinder is set to 11. The counterweight of the second cylinder 6b-1
The combined weight of the first cylinder counterweight 6a-1 and 68-2 for the combined weight of 6th position 1 of 6b-2 is L+x,
If the combined center of gravity of the third cylinder counterweights 6C-1 and 60-2 is L+y, then Mca(L+x)-M
From cc(L+y), hold x-y.

Then, for the longitudinal eccentric force, take out the Y direction component and get (Mca(L+x) +Mcc(L+y))'
cos30'-(-c+ (1/2) ■9)
It is sufficient to satisfy JjL, and the following general formula is obtained.

Mca-Mcb-Mcc-(sc+ (1/2)
ID)/(L+x)...(9) As a result, if the counterweight composite center of gravity position of each cylinder is made to coincide with its center and X-y=゛0, each counterweight composite mass will be calculated as described above. is −c+ (1/
2) lp, which can be arbitrarily determined in relation to the composite center of gravity position. That is, as the values of x and y are increased and the synthetic weights 6 and 1 are moved away from each other, the mass can be made smaller than the above-mentioned values.

Next, on the balancer axis l, since the reciprocating mass of the engine is balanced for each cylinder-corresponding part, it is sufficient to half-balance each cylinder-corresponding part with a mass of ■p/2. Therefore, balancers 8a, 8b,
Let the respective masses of the balancers 8c be Mba, Mbb, and Mbc, and let the positions of the centers of gravity of the balancers 8a and 8c with respect to the central balancer 8b be L+X' and L+y'. Considering the balance of the inertial forces on the balancer axis, Mba= Maintaining Mbb=Mbc
10X') 10Mbc (L1y')) cos3
0'=(Ji/2)spL, it is sufficient to satisfy the relationship, and the following general formula is obtained.

Mba=Mbb=Mbc=e+pL/2(L+x'
)... ■ Here, if x'-v'-〇, that is, the positions of balancers 8b and 8c are aligned with the center of each cylinder, each balancer mass M
ba, Mbb, and Mbc become -p/2. In addition, the center balancer 8b does not need to be aligned with the center of the second cylinder, and the value of The balancers 8a and 8c are connected to the bearing 9 of the crankshaft 1.
By stacking it on the part corresponding to a and 9d, the space can be used effectively. On the other hand, the balancer 8a.

With all of 8b and 8c satisfying the above conditions, power can be transferred to the first cylinder side to distribute power to the bearings 9a, 9b, and Qc phase backing part, or transferred to the third cylinder side to distribute power to the bearing 9.
By arranging the balancer shafts 9b, 9c, and 9d, the space can be effectively utilized for all the balancers, and the balancer shaft 1 can be brought closer to the crankshaft 1.

From this, it can be seen that in the crankshaft 1, the first. To the third cylinder (9
) Counterweights 6a-1 and 68-2 of the synthetic quality ■
, 6b-, 6b-2, 8c4 and 60-2 are provided on the opposite side of the crank pin of each crank arm. Similarly, on the balancer shaft 1, mass balancers 8a, 8b, and 8c of formula (1) are provided in the parts corresponding to the first to third cylinders so as to be half-balanced. The inertial force and couple due to the mass of are balanced.

As is clear from the above description, according to the present invention, in a three-cylinder engine, vibrations and the like are greatly reduced by balancing the inertial force and the couple.

On the crankshaft 1, counterweights 6a-1, 6b-1, 6b-2, and Be-1 are distributed equally for each cylinder.
Since the torque cm2 is provided, a bending moment is not generated in the crankshaft 1 itself, which is advantageous in terms of strength and against elastic vibration. When the balancer weight is placed in a position facing the center of each cylinder, the balancer weight and the large end of the connecting rod have a phase relationship that prevents them from interfering with each other, allowing the crankshaft and balancer shaft to be brought closer together, giving freedom in design. The degree increases. In addition, 2iI balancers 8a and 8c on both sides
By arranging the balancers 8a and 8c in the portion corresponding to the crank wheel bearing, the balancers are spaced apart from each other and the balancer mass can be reduced, and the space for the two balancers 8a and 8c can be used effectively. On the other hand, all balancers 8a,
If 8b and 8c are moved and placed in the bearing-corresponding portion, the space can be utilized to the maximum extent, and size reduction can be achieved by bringing the balancer shaft 1 closer to the crankshaft side.

[Brief explanation of drawings]

1 to 5 are explanatory diagrams for explaining the present invention in detail,
FIG. 6 is a schematic diagram showing an embodiment of a balancer device for a three-cylinder engine according to the present invention. 1... Crank shaft, 2a, 2b, 2c... Crank arm, 6a-1, 6a-2, eb-i, 6b-2
, 6(i-1, fiQ-2m counterweight, 21・
... Balancer shaft, 8a, 8b, 8c... Balancer. Patent applicant: Fuji Heavy Industries Co., Ltd. Agent: Patent attorney: Nobuo Kona, Ukasa Patent attorney: Susumu Murai Figure 4

Claims (1)

[Claims] Counter weights for the reciprocating and rotating mass of the engine are equally provided in the first to third cylinders of the crankshaft, in which the crank arms are sequentially arranged at equal intervals of 120°, and the counterweights for the reciprocating and rotating mass of the engine are provided equally at the same speed and in opposite directions with respect to the upper and lower crankshafts. 1. A balancer device for a three-cylinder engine, characterized in that one balancer shaft is provided which rotates at the same time, and balancers are provided at three locations on the balancer shaft corresponding to the first to third cylinders.