JPS5837349A - Balancer for 3-cylinder engine - Google Patents

Abstract

PURPOSE:To contrive the weight reduction and miniaturization of a balancer by providing balancers in a half-balanced manner at 3 places corresponding to the first, second, and third cylinders of the balancer shaft turning in opposite direction at the same speed as a crankshaft. CONSTITUTION:In the first cylinder of a crankshaft 1, counter weights 6a'-1 and 6a'-2 are provided at 2 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 a 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 all of the first, second, and third cylinders.

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. This 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.The inertia force due to the reciprocating mass is due to the rotating mass. The balance can be half balanced at the same position as the crankshaft, and the remaining part can be balanced by 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 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 counterweight of the crankshaft has a specific separation structure as in Japanese Patent Application Laid-Open No. 55-6035, or
As disclosed in Japanese Patent No. 4-2333, 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 left and right sides of the middle second cylinder. The inertia couple in the longitudinal direction must be taken into account, and this has a large effect on engine vibration. On the other hand, the longitudinal couple of whirling due to this inertial force can be balanced by a balancer on the balancer shaft, but in this case, even if the couple is constant, the mass can be changed according to the distance between the balancers, so the balancer By specifying the mounting position of the balancer shaft, it becomes 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 a balance against inertia force and inertia by using a counterweight on the crankshaft and a balancer on the balancer shaft, and also allows the balancer shaft to be brought closer to the crankshaft side, and the size of the pumice stone can be reduced. An object of the present invention is to provide a balancer device for a three-cylinder engine.

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 rod, and 5 is the piston. A counterweight 6 is provided on the extension line of the crank arm 2 on the side opposite to the crank bin 3 to half balance the entire inertia force due to the rotating mass and the inertia force due to the reciprocating mass.
One balancer shaft 1 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. As shown in the figure, when the crank arm 2 is positioned clockwise by θ from the top of the two axes, the balancer 8 of the balancer shaft 7 is positioned counterclockwise by the same θ from the bottom of the Z axis. Here, if the inertial mass of the reciprocating part is mp, and the equivalent inertial mass of the crank bin 3 of the rotating part is Ic to make it easier to understand, then the mass of the counterweight 6 on the crankshaft side is relative to the reciprocating mass ■. Should it be half balanced?'r
″mp/2, crankshaft 1 for rotary Jlic
Since it rotates in the same direction as , all of them can be balanced and become Ic, and the total is (II) / 2) + lIC
becomes. Further, the mass of the balancer 8 on the balancer shaft side is the remainder of the above-mentioned reciprocating mass and becomes l1lp/2.

By doing so, the inertial forces in the 7°Yh direction of the reciprocating portion and the rotating portion are balanced. Therefore, in a three-cylinder engine, if a counterweight 6 and a balancer 8 of the above-mentioned masses are attached to positions corresponding to each cylinder, then in this case, the total mass of the counterweights on the crankshaft side is 3.
((llp/2)+mc), the total balancer mass 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 3rd cylinder is indicated by suffix a or c,
Further, the second cylinder is at the top dead center, the -A11 cylinder is rotated 240 degrees from it, and the third cylinder is rotated 120 degrees.

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 Fp3 of the third cylinder are as follows.

Fpl=lpr O2(O8(θ+240)Fp2=m
pr O2 cos θ Fp3=a+pr to2 cos (θ+120)
Therefore, the total inertial force is balanced by F I)1+ F I12+ F p3-0.

In addition, in order to have a negative membrane property, the inertia couple in the longitudinal direction of the crankshaft is viewed from a point P that is a distance S apart from the first cylinder, and if the pitch of each cylinder is L, then Fpl・S+Fp2 (S+1) 10f13(S+21>
It is indicated by.

That is, Fpl・S+Fp2(S+1)+Fp3(S+21.-
)---Jimpr oo21sinθ---(1), and a longitudinal couple 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, 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 2G. Therefore, in the seven directions when moving by θ from this state, the forces caused by each counterweight mass are Freal, Frec2, Frec2, and Frec2.
c3 becomes as follows.

FreCl-(In/2) r (c)2
cos (θ +240 +180) Frec
2= (In/2) r oo2 cos (θ+
180) Frec3-(In/2) r ω2 c
os (θ+120 +iao > Therefore, the inertia 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 the force in the Z direction is obtained in the same manner as above, F real-S + F rec2 (S + L
> + F rec3 (S +21> = (IT/2) mpr ω2 L sin θ
---<28), 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 in this Y direction (the inertia force is balanced in the X direction, the inertia couple in the longitudinal direction due to the force in the Y direction is as follows. become that way.

-(m/2) apr (Z)2 LCO8θ,
, -(2b) That is, a longitudinal couple around the Z axis is generated due to the force in the Y direction.

Above, the counterweight 6a on the crankshaft side (X 6
The longitudinal inertia couple caused by G is Y due to the Z direction.
This occurs around the axis and around the Z axis due to the Y direction, and the combination of both is as follows.

(ffi/2) mpr ω2 L sin θ−(
j'j/2) iprXω2 L003θ - (In/2) mprω2 L (sinθ-c
osθ)・・・・(3) By the way, in addition to providing the above-mentioned crankshaft side counterweight for each cylinder, it is also possible to separately provide the counterweight on the first and third cylinders on both sides except for the second cylinder in the center. This is also possible, and this case will be explained with reference to FIG. To state the results without explaining the intermediate steps, the counterweights 6j and 60' of the first and third cylinders are <m/2) (II)
/2), and the counterweight side of the first cylinder is:
This is a position further 30' phase ahead of the position 180° phase advanced from crank arm 2a, and the third cylinder counterweight 6σ is 30' phase behind the position 180° phase advanced from crank arm 2C. provided at the location. That is, both counterways, rxt, and sσ are 180° opposite to the crankshaft 1, and the central crank arm 2b
This is the position perpendicular to .

In this case as well, when moving by θ from the state shown in the figure, 7
Force F rec1' due to each counterweight mass in the direction
, F rec3' is Frecl' = (j'j
/2) (ml)/2) r Q)2xcos(
θ+240 +180 +30) Frec3' = (
And/2) (In/2) rω2xcos(θ+
120 +180-30), and the unidirectional inertial force is Freal' + Frec3' -Q,
Of course it's balanced.

Next, the longitudinal inertia couple due to this Z-direction force is Frecl'``s+l''re03' (S+21
)−(j”j/2) II)rω2Lsinθ, 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).

Therefore, even if one counterweight on the crankshaft side is provided for each cylinder, or one only for the 1st and 3rd cylinders, the inertia force will be balanced, and the inertia couple in the longitudinal direction will It is understood that they will be 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. , when this is synthesized, −jTa+pr ω21sinθ+<Ji/2) l
pr ω21-(sin θ-COS θ) --(month/2) mpr ω2 L (sin
θ+CO3θ)・・・・(→ Therefore, we will explain how to balance such longitudinal eccentric force on the balancer shaft side with reference to Fig. 5. 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 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 8C corresponding to the third cylinder is rotated counterclockwise 1
It is located at a position further advanced by 1806 phases from the 20° position.

Therefore, the force F in the Z direction when moving by θ from this state
recl, F rec2. Frec3 is Fre
c1= (ip/2) r ω2 cos (θ+
240 +180) Frec2-(sp/2)
r oo2 cos (θ+180) Frec3=
(Illp/2) r ω2 cos (θ+12
0 +180 ), the inertial forces in two directions are balanced, and the longitudinal couple around the Y axis due to this force in the Z direction is (j'N/2)++prω2Lsinθ−−−(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 7 wheels due to this Y direction force is (IN/2) m
pr ω2L cos θ --- (2b') Therefore, the inertia couple in the longitudinal direction generated by the balancers 8a to 8c on the balancer axis side is also generated around the Y-axis in two directions and in the Y-direction.
This occurs around the axis, and the combined result is as follows using equations (2a') and (2b') above.

(jN/2)mprω2L(sinO+cosθ)・・
・(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 shown in FIG. 4. To explain this case with reference to FIG. The mass of the balancer equivalent to 3 cylinders is sp/
2 multiplied by 5/2, the cylinder equivalent to the first cylinder is positioned with a further 30° phase advance, and the cylinder equivalent to the third cylinder is positioned M (with a 30' phase delay). This gives the same result as in Figure 5, and can be replaced by that.

As mentioned above, the balance of inertia 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 inertia couple in the longitudinal direction due to the reciprocating mass generated on the crankshaft side and the mass of the counterweight that half-balances it. 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. Fc3 is as follows.

Fc1=01cr ω2 CO3(θ+240)Fc2
=mcr ω2 cosθ Fc3=mcr ω2 cos (θ+120) As a result, the longitudinal couple around the Y axis due to the rotating mass is -j'j
mcr ω2 L sinθ ---(5a) The longitudinal couple around the two axes becomes Hracr ω21cosθ ---(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.

-mmcr (1)2 L (sinθ-cosθ)-
--(6) Next, this rotation 'l1II is changed to 1 for each cylinder.
Counterweight 6a or 6 balanced with =1
The balance due to the mass of c is similar to the configuration shown in Figure 3, and the force due to the mass of each counterweight, F
rotl, F rot2. F'rot3 will be next.

Fr0tl=lCr ω2 (ios (θ+240
+180))”rot2=mcr ω2 cos
(θ+180) Frot3=++cr ω2 cos
(θ+120 +180) As a result, the longitudinal couple around the Y-axis in two directions becomes J'Nmcr (iJ21
sinθ ---(7a) The longitudinal eccentric force around the Z-axis due to the Y direction is -5m0r (ZJ2' LCO3θ ---(7b
), and the combination of the two results in the following swing.

F3mcr ω2 L (Sin θ-cos θ)
--(Ill) By the way, also in the case of such a rotating mass, as shown in Figure 4, multiply the mass by -C by (old/2),
By advancing or retarding the 30' phase, it is possible to separate and concentrate the counterweights on the first and third cylinders.

Thus, regarding the rotating mass, the resultant whirling longitudinal couple around the Y-wheel and Z-axis in equation (6) becomes zero by combining with the similar longitudinal couple in equation (8) due to the counterweight, and becomes 2. 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. 7. In the crankshaft 1, as shown in FIG. A counterweight is installed in the cylinder, and in this case, in order to increase the degree of freedom in attaching the weight, the first
In the cylinder, 2 corresponding to both crank arms 2a-1 and 2a-2
In the third cylinder, counterweights 6σ-1 and 6σ-2 are similarly provided at two locations corresponding to crank arms 2cm1 and 2cm2. Further, on the balancer shaft 7, as shown in FIG. 5, balancers 8a and 8b are provided at positions corresponding to all of the first to third cylinders, respectively.

8C is provided.

Two counterweights of crankshaft 1 -1゜ba-2
The proportions of the masses do not necessarily have to be equal, and can be determined arbitrarily by simply changing the position of the composite center of gravity, and the same holds true for the other two counterweights 6 -1°6σ-2. In addition, when the mass of the reciprocating part and rotating part of the engine is separated and concentrated on the first and third cylinder sides, as is clear from the above explanation, the combined mass on each cylinder side is (<+p/2
) +mc) (IT/2), it is sufficient to adjust the phase by 30 degrees, so if the pitch of each cylinder is L as in Fig. 2, for the longitudinal couple, (ip/2) +mc) (Ji /2) x2
L=<E/2) spL + JascL may be generated.

Therefore, if the combined mass of the counterweights m-z and m-2 is Mca', and the combined N suspension of the counterweights 6σ-1 and 6σ-2 is MCC', then considering the balance of the inertial force on the crankshaft 1, Therefore, it is necessary to hold Mea' = lvlcc'.

Then, the combined center of gravity position of the counterweights 68'-1 and 61-2 is L+×, and the counterweights 6σ-1 and 6-
If the composite center of gravity position of 2 is L+y, Mca'(=MOC') X (L+X +L+
1 ) = (IN/2) mpL+Jis+cL can be formed into a vortex layer, so Mca' = Mcc' = ((Jj/2) mpL
+Ja+cL)/(21+X+y)...
・It becomes (9).

Here, if x = y = o, that is, the combined center of gravity positions of the counterweight side -1°6co2 and 6cow -1,6σ-2 are made to match the pitch of each cylinder, the masses Mca', Mcc
' becomes (Takumi/4)*p+(Takumi/2)sc. Also, x
, y can be arbitrarily determined, so the larger the value and the farther the center of gravity is, the more the mass Mca' and MCC' will be 7.
ノ) Saku and perform.

Next, in the balancer shaft 7, as is clear from the above explanation, the mass is only the reciprocating part of the engine, and the mass is 1 for each cylinder.
It is sufficient to perform half balance with a mass of 1l)/2. Therefore, the mass of each balancer 8a, ab, 8c is Mba,
Mbb, fvjbc, and the center of gravity positions of the balancers 8a and 8c with respect to the central balancer 8b are x/, y
l, then considering the balance of inertial force on the balancer axis, Mba-Mbb=Mbc x' = y'
For the longitudinal couple, the Y-direction components of the balancers 8a and 8c corresponding to the first and third cylinders are taken to satisfy the following equation.

(Mba(L+x')+Mbc(L+y'))
xcos30- (IT/2) II) L, that is, Mba-Mbb=Mbc=lIIL/2 (L+x
)...@) Here, x'=y'=0, that is, balancers 8a, 8b, 8
If the interval between b and 80 is made to match the pitch of each cylinder, each balancer mass Mba, Mbb, Mbc becomes -p/2.

Also, the center balancer 8b is aligned with the center of the second air hook V
There is no core principle of X' by separating the positions of each balancer
The larger the value of , the smaller the balancer mass becomes.
, If placed in the area corresponding to 9d, the space can be used effectively. On the other hand, balancers 8a, 8b, 8c
The entire bearing 9a is moved to the first cylinder side.

If you place it in the part corresponding to 9J 9c, or move it to the third cylinder side and place it in the part corresponding to bearings 9b, 9c, 9d,
For all the balancers 8a, sb, and 8c, the space of the crankshaft bearing portion can be used effectively, and the balancer shaft 1 can be brought closer to the crankshaft 1.

From this, in the crankshaft 1, the mass both satisfy equation (9), and the counterweight 6
The positions a-1 and 6j-2 are on the opposite side from the crank pin, with the phase advanced by 30°, and the counterweights 6σ-1, 6σ-2
The position is on the opposite side from the crank pin, the phase is shifted by 30' il, and both are perpendicular to the crank arm 2b of the second cylinder. On balancer shaft 1, balancers 8a, 8b,
8c is half-balanced at any position corresponding to each cylinder with a mass that satisfies equation ([l), and as a result, the inertial force and couple due to the masses of the reciprocating part and rotating part of the three-cylinder engine are balanced.

This greatly reduces engine vibration, etc. Counterweight m of crankshaft 1,,er-2,6-1゜6σ
-2 and the balancer shaft 7, the degree of freedom in design increases. In particular, the two balancers 8a on both sides,
If at is placed in a portion corresponding to the crankshaft bearing, the mass will be small and rigidity will be increased, and the balancers 8a and 8h will be easier to mount due to effective use of space. At this time, the central balancer 8b is placed approximately in line with the portion corresponding to the second cylinder, but since the second cylinder on the crankshaft side has no counterweight and only the crank arm 2b, it is difficult to install the balancer 8b. On the other hand, the balancer shaft 1 can be moved as close as possible to the crankshaft side without being so limited. Next, by moving all of the balancers 8a, 8b, and 8c and arranging them in the bearing-corresponding portion, the space can be utilized to the maximum extent, and the balancer shaft 7 can be brought closer to the crankshaft side, thereby making it possible to further reduce the size.

A specific example of mounting the balancer shaft will be explained with reference to FIGS. 8 and 9. The one in Fig. 8 shows the case where the engine is assembled under the cargo bed in the R-R system, and the engine body 10
is mounted approximately horizontally, and this engine body 10
An air cleaner 11, a carburetor 12, and a suction pipe 13 are horizontally connected and installed immediately above the middle, and a cooler compressor 14, ACG 15, etc. are also attached. Therefore, if you pull the balancer shaft 1 upward to avoid submerging it in the oil,
Since it comes to interfere with the aggravator 12, AC015, etc., it is advantageous to be able to move it closer to the crankshaft 1 side because such interference can be avoided.

The one in Fig. 9 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 17 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 11, etc. can be avoided, and the engine body 10 can be moved closer to the front panel to make the cabin wider. Various effects can be obtained.

[Brief explanation of the drawing]

1 to 6 are explanatory diagrams for explaining the present invention in detail,
Figure 7 shows the balancer installation for a three-cylinder engine according to the present invention! FIGS. 8 and 9 are side views showing a specific example in which the present invention is applied to an automobile. 1... Crankshaft, 2, 2a, 2b, 2c,
2a-z, 2a-2. 2cm1, 2cm2...crank arm, 6. Side-1,
Ba-2,6σ-1゜6go-2...Counterweight,
7... Balancer shaft, 8° 8a, 8b, 8cm...
Balancer, 9a, 9b, 9c, 9d--Bearing. 20-2 2C-2 7 Figure 8 9FIA

Claims (1)

[Claims] On the crankshaft, in which the crank arms are sequentially arranged at equal intervals of 120 degrees, the crank arms of the first and third cylinders are placed at positions perpendicular to the crank arms of the second cylinder on the opposite side of the crank pin. A counterweight of mass is provided, and a balancer shaft is provided that rotates at the same speed and in an opposite direction to the crankshaft, and in the balancer shaft, a first,
A balancer device for a three-cylinder engine, characterized in that balancers of a predetermined mass are provided at three locations corresponding to the second and third cylinders in a half-balance manner.