JPS5839855A - Balancer for three-cylinder engine - Google Patents

Abstract

PURPOSE:To reduce vibrations and to lighten and make small in size a balancing device by disposing a balancer shaft in parallel to a crank shaft in which counterweights are disposed uniformly on each crank arm, and by disposing two pairs of balancers on each two positions of said balancing shaft corresponding to bearings of the first and third cylinders. CONSTITUTION:Counterweights 6a-1, 6a-2; 6b-1, 6b-2; 6c-1, 6c-2 for the mass of a reciprocating portion and a revolving portion of an engine are disposed uniformly on each of crank arms, disposed by equal spaces of 120 deg., of the first, second and third cylinders of a crank shaft 1. One balancing shaft 7 is placed, which revolves in the opposite direction to and at the same speed as said crank shaft 1. Then, two pairs of balancers 8a'-1, 8a'-2; 8c'-1, 8c'-2 are disposed on the positions of said balancer shaft 7 corresponding to bearings 9a, 9b, 9c, 9d of said first and third cylinders, respectively.

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. and balancer equipment 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 fourth-order inertia couple in the longitudinal direction of the crankshaft.
ca.

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 is due to the single rotating mass. It is possible to half-balance in the same position as the case, 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 three-cylinder engine, even though the inertia forces of each air W4 are balanced as described above and the inertia couple around the X axis is also balanced, an inertia couple in the longitudinal direction occurs, and this inertia couple is In order to eliminate the balance, the counterweight of the crankshaft has a specific separation structure as disclosed in Japanese Patent Application Laid-open No. 55-6035, or the inertia couple of the crankshaft system as in Japanese Patent Publication No. 54-2333@. There is one that generates an inertia couple of the same magnitude but in opposite directions 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 changed depending on the distance between the balancers, so the balancer By specifying the mounting position of the balancer shaft itself, it becomes very advantageous in terms of the structure of the balancer shaft itself, the degree of freedom in design, the positional relationship with respect to the crankshaft, etc.

In view of these circumstances, the present invention achieves a balance against inertia force and inertial couple by using a counterweight of the crankshaft and a balancer of the balancer shaft, and also aims at making the balancer shaft closer to the crankshaft side and reducing its weight and size. A further object of the present invention is to provide a balancer device for a three-cylinder engine that is capable of dealing with problems caused by the balancer shaft being axially supported and the balancer being immersed in oil.

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings. First, in Fig. 1, the balance system per cylinder will be explained. In the figure, numeral 1 is the crankshaft, 2
are crank arms sequentially arranged at equal intervals of 120°, 3 is a crank bin, 4 is a ]-rod, and 5 is a piston.
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 seventh wheel -I:aIi, the balancer 8 of the balancer shaft 1 is positioned counterclockwise by the same θ from the lower part of the Z-axis. Here, the inertial mass of the reciprocating part is mp, and R light is easy to understand (so, if the equivalent inertial mass of the rotating part crankbin 3 is 10, the mass of the counterweight 6 on the crankshaft side is reciprocating mass - p) For the rotational mass -G, it is only necessary to half-balance it, so ■p/2, and for the rotating mass -G, it rotates in the same direction as the crankshaft 1, so it is possible to balance all of them, resulting in ■C, and the total is ( -p/2), +s
c. 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 Z of the reciprocating part and the rotating part.

The inertia forces in the Y direction are all balanced. Therefore 3
In a cylinder engine, if a counterweight 6 and a balancer 8 of each mass are attached to the positions corresponding to each cylinder, then in this case, the total mass of the counterweights on the crankshaft side is 3 ((sp/2) + SC), and the balancer shaft The total mass of the side balancers is (3/2) ID.

Next, the balance due to the mass of the reciprocating part in a three-cylinder engine will be explained with reference to Figure 2.
to 3rd cylinder are indicated by suffixes a to c, and the 2nd cylinder is at top dead center (A5-), the 1st cylinder is rotated 24° from it, and the 3rd cylinder is rotated 120°. It is in 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 FI13 of the third cylinder are as follows.

Fl)1=lIl)r ω200B (θ+240)
F p2= wpr ω2' cos θFp3=
apr (Z)2 cos (θ+120) 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, we will look at it from a point P, which is a distance l1w1s away from the first cylinder, in order to have a -membrane property, and if we consider the pitch of each cylinder, then Fpl-8+-Fp2 (S 10L) 10Fp3 (S+21)
It is indicated by.

That is, 111-8+FI12(S+1)+Fp3(8+21
) = −1j*pr ω2 1 sin θ−
--(1) 6, and the reciprocating mass, which is a bidirectional load, generates a eldest couple around the Y-axis.

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 1806 phases ahead of 2C. Therefore, in the 7 directions when the counterweight moves by θ from this state, the force f-real, F rec2 due to each counterweight mass is
, FreC3 becomes as follows.

F real = (sp/2) r oo2 co
s (θ+240 +180) Frec2= (
sp/2 ) r ω2 cos (θ +
180) Frec3= (g+p/2) r
oo2 cos (θ +120 +180
) Therefore, the inertial force in the Z direction is 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 obtained in the same manner as above, Frecl-3 + Frec2 (Sil-) + Frec
3(S+2 [) = (j'N/2) ipr oo2 Lsinθ・
--(2a), and similarly generates a longitudinal couple around the Y axis.

The counterweights 6a, eb, 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. Become.

-(m/2) ipr (Z)2'L CO3
θ---(2b)- That is, a longitudinal bias force around the two axes is generated due to the force in the Y direction.

Above, the counterweights 6a to 60 on the crankshaft side
The inertia joint horn in the longitudinal direction caused by is 7 due to two directions.
It occurs around the wheel and around the two wheels in the Y direction, and the combination of both is as follows.

<5/2) spr ω2 1 sin θ
−(Jj/2) apr×ω21 cos θ = (Fr72) iprω2L (sin θ−C
O5θ)・・・・(3) Above, we have explained the balance of inertia force due to the reciprocating mass and counterweight on the crankshaft, and the longitudinal inertia joint horn, that is, whirling.
The longitudinal bias force in the equation remains, and when combined, −fjspr ω21 sinθ+(ff/2) s
pr w2XL (Sinθ-COSθ) m-(V3/2) mpr ω2L (sinθ+
cos θ)...(4) Therefore, how to balance such longitudinal eccentric force on the balancer shaft side will be explained with reference to FIG. 4. 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 -p/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.
In the shifted position, the balancer 80 corresponding to the third cylinder is rotated counterclockwise by 1.
It is located at a position further 180° in phase from the 20° position.

Therefore, when moving by θ from this state, the two directions 9- ] Frecl, Frec2.
Frec3 is Frecl= (ip/
2) r ω 2 cos (/
7-1-240 +180) Frec2=
(mp/2 >, r ω2 cos (θ+180)
Frec3= (lp/2), T (c)2
0O8(θ-4-120+180),
The inertial force in the Z direction is balanced, and the longitudinal couple around the Y axis due to the forces in these two directions is (j'N/2) g+pr oo2 L s
in 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 balanced in the same way, and the first child couple around the 7 wheels due to the force in the Y direction is (j'j/2) apr ω2 L cosθ
---(2b') Therefore, the inertia couple in the longitudinal direction generated by the balancers 8a to 8c on the balancer shaft side also occurs around the 7 wheels in the Z direction and around the 7 wheels in the Y direction, and the combined force is the above ( Using equations 2a') and 2b', we get the following.

(j'j/2) spr ω2 1 (si
n θ + CO8θ )...(4') By the way, the balancer on the balancer shaft side is not only provided for each cylinder equivalent part, but also for the 10 - equivalent parts of the 1st and 3rd cylinders on both sides except for the 2nd cylinder in the center. It is also possible to provide them separately and assembling them, and this case will be explained with reference to FIG. To state the results, omitting the intermediate details, the mass of the balancer d corresponding to the first and third cylinders is (-11
/2) is multiplied by (hill/2), and the balancer C for the part corresponding to the first cylinder is located 30" ahead of the half-balanced one mentioned above, and the balancer C for the part corresponding to the third cylinder is Conversely, both balancers U are positioned with a 30° phase lag.

a[' is provided at a position perpendicular to the crank arm 2b of the central second cylinder.

In this case as well, when moving by θ from the state shown in the figure, 7
The forces in the directions Frecl' and Frec3' are
c1' = (Jj/2) (Ip/2) r
ω2xcos(θ+240+ 180+ 30)Fre
c3' = (ffi/2) (-FI/2
) rω2xcos(θ+ 120+ 18
0-30), and these two-directional inertial forces are balanced by F rea1' + F rec3' -0.

Next, the longitudinal couple around the Y axis due to the forces in these two directions is F real' - S + F rec3' (S
+ 21 ＞= (r:3/2) sp
rω2 L sinθ, which agrees with equation (2a').

On the other hand, in the Y direction, the polarity becomes negative and CO3 becomes sin, and the inertial force is balanced, and the longitudinal inertia couple around the Z axis due to the force in the Y direction matches equation (2b').

From this, the inertia force is balanced by the two balancers provided in the parts corresponding to the first and third cylinders, and Z, and the inertia couple in the longitudinal direction is consistent with equation (4') and is equal to the half-balanced case. You can replace it with the same result.

As mentioned above, the balance of inertial force by the balancer on the balancer shaft side,
This is an explanation of the example horn of inertia 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 inertia in the longitudinal direction due to the mass of the reciprocating composite layer generated on the crankshaft side and the counterweight that half-balances each. The couple is 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, Fc
1. Fc2. l''c3 becomes -.

F Ol−g+crω2 cos (θ+240)F
c2=mcr O2CO8θ Fc3-mar w2 cos (θ+120) As a result, the longitudinal couple around the Y-axis due to the rotating mass is -Jjw
cr oo2 L sin θ --- (5a) The longitudinal eccentric force around the Z axis is m g + cr oo 2 L008 θ −
--(5b), which similarly occurs around the Y axis in two directions and around the Z axis in the Y direction, and when combined, it becomes as follows.

-5mar to2 1 (sin θ -co
s θ )---(6) Next, a counterweight 6a that balances this rotating mass at 1 = 1 for each cylinder
To explain the balance by mass of 6C to 6C, it is the same as configuration 13- in Fig. 3, and the force due to each counterweight mass, F
rotl, F rot2. F rot3 is as follows.

Frotl=lcr O2008(θ+240 +18
0 ) Frot2=-++cr (132CO3(θ+
180) Frot3=i+cr O2cos (θ→
-120+-180) As a result, the longitudinal eccentric force around the Y wheel due to the Zh direction is j'jgicr O2L sinθ
---(7a) The longitudinal couple around the Z-axis due to the Y direction is -Hmcr cc>21 cosθ ---(7b)
The combination of the two results in the following swing.

old-cr O2L(sin θ-cos θ
) --(8) Thus, regarding the rotating mass, the composite whirling longitudinal couple around the Y axis and two axes in equation (6) can be reduced to zero by combining with the similar longitudinal couple in equation (8) due to the counterweight. Then, the two parties will be balanced.

The present invention is based on such a technical idea, and a specific embodiment thereof will be explained with reference to FIG. Since inertia force and couple force are generated due to
2, 6L1 and 6b-2, 6cm1 and 6cm2 are provided on the opposite side of the crank pin of each crank arm as shown in FIG. In addition, in the balancer shaft 1, as shown in Fig. 5, the second
In particular, two crankshaft bearings 9a and 9b on the side of the first and third cylindrical parts, excluding the part corresponding to the cylindrical part, i''.

Two sets of balancers 1 and 2 are placed at the locations corresponding to 9C and 9d. 4-1 and 4-2 are provided.

In such a configuration, first considering the balance on the crankshaft side, each cylinder has a counterweight for the combined quality of the reciprocating and rotating parts, so the counterweight 6a-1 of the first cylinder and 6a-2, the counterweights 6b-1 and 6b-2 of the second cylinder, and the counterweights 6cm1 and 60-2 of the third cylinder, respectively. Considering the balance 5, Mca=Mc
Holding b=Mcc, sc+ (1,,'2)■p, the resultant center of gravity position does not need to coincide with the center of each cylinder, but the pitch of each cylinder is maintained, and the counterweight of the second cylinder ab- , and 6b-2, the combined center of gravity position of the first cylinder counterweights 68-1 and 68-2 is L+X, and the third cylinder counterweights 6C-1 and 60
If the composite center of gravity position of -2 is 1+-y, then Mca(L+
x ) = Mcc (L + y ), hold x = y.

Therefore, for the longitudinal couple, take out the Y-direction component and obtain (Mca(L +x) −Bv4cc(1+y)
) cos30- (Peng c+ (1/2) gt
p) Just add ffL, and the following general formula is obtained.

Mca=Mcb=Mcc== (mc+ (L/2)
sp) 1/(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 it is written as X = y = O,
As mentioned above, the combined mass of each counterweight is mc+ (
1/2) ml), but it can be arbitrarily determined in relation to the position of the composite center of gravity. That is, the mass of the rod that increases the values of x and y and moves the combined center of gravity positions away from each other can be smaller than the above-mentioned value.

Next, in the balancer shaft 1, as is clear from the above explanation f' It is sufficient to sell (■p/2) to <V3/2) and adjust the phase by 30', (ip/2)
It is sufficient to generate a longitudinal couple of (old/2)2L=(old/211)L.

Therefore, the combined mass of balancer G1 and G2 is Mba'.

If the combined mass of balancer 4-1 and binding 2 is M bc', M b
If a'=M bc' is held, and the combined center of gravity positions of balancer 1 and side 2 are L+ and X', and the combined center of gravity positions of balancer 4-1 and W- and H are L+V', then Mba' ( L+ x' +L+ ¥'
)-(J'j/2)lpL,
It becomes the following 11 general formula.

Mba' = Mbc' = (j'j/2) IpL/
(2 L+ (and furthermore, the resultant center of gravity positions are separated from each other)
By doing so, the mass of the paranza can be kept small.

From this, in the crank wheel 1, the counterweights 6a-1 and 6a of the combined mass of equation (9) are applied to the first to third cylinders.
-2, 6b-1 and 6b-2, 13cm1 and 60-2 are provided on the opposite side of the crank pin of each crank arm. In addition, in the balancer shaft 7, the combination 1 of the formula
m balancer shaft E and P 2+8C'-1 and 8c'-2
is placed at right angles to the crank arm of the second cylinder, thereby balancing the inertia force due to the mass of the active and rotating parts of the three-cylinder engine and the unbalanced couple. Fit.

Then, a total of four balancers M-1, M-2, and 8c'-1, which are tiered weights, are distributed two by two into 2-'11.
2 are arranged in corresponding parts of the bearings 9a to 9d that are shifted from the counterweights 18-18 in each cylinder of the crankshaft 1, and are configured so that they do not interfere with the counterweights. It is possible to arrange it close to the crankshaft 1 side without interfering with the counterweight.

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 primary inertial force and the inertial couple. Counterweights 6a- are applied equally to each cylinder on the crankshaft 1.
1 and 6a-2, 6b-1 and 6b-2, 6c-1 and 6G-
2 is provided, no bending moment is generated in the crankshaft 1 itself, which is advantageous in terms of strength and against elastic vibration. Since generality is taken into account regarding the installation of the counterweight and balancer, the degree of freedom in design is increased. On balancer axis 7, balancer pi 1 and M-2, 8c! Since both B-1 and B-2 are arranged in the portion corresponding to the crankshaft bearing, the balancer shaft 7 can be moved closer to the crankshaft 1 by effectively utilizing the space of the bearing, contributing to miniaturization. In addition, the balancer mass is increased by 2.11 to 2.
By distributing the balancers into groups, the balancer can be installed without any shortage.

A specific example of mounting the balancer shaft will be explained with reference to FIGS. 7 and 8. The one in Fig. 7 shows the case where the engine is installed under the cargo bed in the R-R system, and the engine body 10
is mounted almost horizontally, one engine body 10
An air cleaner 11, a carburetor 12, and a suction pipe 13 are horizontally connected and installed just above the middle, and a cooler compressor 14, ACG 15, etc. are also attached. Therefore, if the balancer shaft 7 is installed above so as not to be submerged in oil, it will interfere with the carburetor 12, ACG 15, etc., and the best way to avoid such interference is to move it closer to the crankshaft 1 side. This will give you an advantage.

The one in Fig. 8 is an F-F type, in which the engine body 10 is mounted almost vertically, the air cleaner 11, carburetor 12, and intake pipe 13 are provided on the passenger compartment side, and the exhaust pipe 16 is provided on the front panel side. Therefore, if the balancer shaft 7 is placed in front of the engine body 10, it will interfere with the catalytic converter 11 of the exhaust pipe 16. Therefore, in this case as well, if the balancer shaft 1 can be moved closer to the crankshaft 1, interference with the catalytic converter 17 etc. can be avoided, and the engine body 10 can be moved closer to the front panel side to make the cabin wider. Various effects can be obtained, such as the ability to

[Brief explanation of the drawing]

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, and FIGS. 7 and 8 are side views showing a specific example of a one-cylinder engine in which the present invention is applied to an automobile. 1... Crank shaft, 2a, 2b, 2c... Crank arm, 6a-1, 6a-2, 6L1, 6b-2, 6
cm1.6cm2--Counterweight, 1...Balancer shaft, "-t l &1-2, &!-5, B2...Balancer, 9a, 9b, 9c, 9d.
...Crankshaft bearing. 21-

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 crankshaft. A single balancer shaft that rotates is provided in G, and two balancers are provided in two phases each on the two bearing-equivalent parts on the first cylinder side and the bearing-equivalent part on the third cylinder side 21 of the balancer shaft. A balancer device for a 3-cylinder engine featuring the following.