JPS5837350A - Balancer for 3-cylinder engine - Google Patents

Abstract

PURPOSE:To attain the weight reduction and miniaturization of a balancer by using balancers on both ends, among balancers provided in half-balanced manner at 3 places corresponding to the first, second, and third cylinders of the balancer shaft, as bearing 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 such that it turns 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, and of these, the balancers 8a and 8c are used as bearings 23 concurrently.

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 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 is It is possible to half-balance at the same position as with the mass, and balance the remaining part with a balancer shaft that rotates in the opposite direction at the same speed as the crankshaft. By the way, in the case of a 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 eliminate this problem, conventional methods have been used, such as those in which the counterweight of the crankshaft has a specific separation structure, as 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 force 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 couple due to the whirling due to the inertia 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 By specifying the mounting position of the balancer, 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 balance against inertial force and inertial couple by using a counterweight on the crankshaft and a balancer on the balancer shaft, and also brings the balancer shaft closer to the crankshaft side, making it lighter and smaller. An object of the present invention is to provide a balancer device for a three-cylinder engine that is advantageous for bearing support and prevents inconveniences when a balancer shaft is immersed in oil.

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings. First, to explain the balance system per cylinder in Fig. 1, in the figure, numeral 1 is the crankshaft, 2 is the crank arm arranged at equal intervals of 120°, 3 is the crank bin, 4 is the connecting rod, and 5 is the crankshaft. 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 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. 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 7 is positioned so that it is positioned counterclockwise by the same amount θ from the bottom of the Z-axis. Here, if the amount of inertia T1 of the reciprocating part is IRD, and to make the explanation easier to understand, the equivalent inertial mass in the crank bin 3 of the rotating part is tic, then the mass of the counterweight 6 on the crankshaft side is relative to the reciprocating mass. For the rotating quality fltmc, it only needs to be half-balanced, so it is mp/2, and since it rotates in the same direction as the crankshaft 1, it is possible to balance all of it, resulting in a PC, and the total is (IIIp/2) +
It becomes 1lIC. 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 inertial horns in the Yh direction are all balanced. Therefore, in a three-cylinder engine, if a counterweight 6 and a balun 1 and 8 are attached to the positions corresponding to each cylinder, the total mass of the counterweights on the crankshaft side is 3 ((lit)/ 2) At 1mC), the total balancer mass on the balancer shaft side is (' 3/2)
It becomes Ip.

Next, the balance of 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,
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 second cylinder, and the excitation force Fp3 of the third cylinder are as follows.

Fp1=Shi p “ω2 cos (θ+240)1”
p2= mprω200Sθ Fp3-+npr oo2 cos (θ+120)
Therefore, the total inertial force is balanced by F p1+ F p2+ F p'3=0.

In addition, in order to give the inertia couple in the longitudinal direction of the crankshaft a -membrane property, we will look at it from a point P, which is a distance S from the first cylinder and a distance c, and the pitch of each cylinder will be [, then Fl) 1・S+Fp2(S+1)+Fp3(S+21)
It is indicated by.

That is, F”pl・S+Fp2(S+L)+Fp3(S+21)
= −1'Tipr ω2 L sinθ---(1)
Therefore, a longitudinal couple is generated around the Y axis due to the reciprocating mass which is the Zh direction 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 2C. Therefore, in the seven directions when moving by θ from this state, the forces due to each counterweight mass F recl, F rec2, F
rec3 becomes as follows.

Frecl = (1111/2) r ω2 CO
3(θ+240 +180) Frec2= (Mp/
2) r ai2 cos (θ+180)F r
ec3= (llo/2) r ω2cos (θ
+120 +180) Therefore, the inertial force in the Z direction is F reci + F reC2+ Frec3= Q
This balances out.

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 −3+ F rec2 (S + L
) + Frec3 (S +21> = (JT/2) a+prooo213inθ--
-'-4'2a), which similarly produces a longitudinal couple around the Y-axis.

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

-(IN/2) ipr oo2Laosθ---(
2b) That is, a longitudinal couple around two axes is generated due to the force in the Y direction.

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

(Old/2) o+pr oo21 sinθ-(J'
i/2) Ipr×ω2LCO3θ = (J'j/2) mprω2 L (sinθ
-cos θ) ・ ・ ・ (3) By the way, in addition to providing the above-mentioned counterway 1 on the crankshaft side for each cylinder, it is also separately assembled in the 1st and 3rd cylinders on both sides except for the 2nd cylinder in the center. It is also possible to provide the same, and this case will be explained with reference to FIG. To state the results without explaining the intermediate progress, the counterweights ea' and e of the first and third cylinders are (JT/2) (
With a mass of mp/2), the counterweight of the first cylinder is at a position further 30° phase advanced from the position 180° phase advanced from the crank arm 2a, and the counterweight 6 of the third cylinder ( ' is 180° from crank arm 2C
It is provided at a position where the phase is delayed by 30° from the position where the phase is advanced. In other words, both counterweights 6 and 6 are positioned 1806 opposite to the crankshaft 1 and perpendicular to the central crank arm 2b.

In this case as well, when moving by θ from the state shown in the figure, 7
The force due to each counterweight mass in the direction “rec7’
, Frec3' is Frecl' = (Ji/2
) (w+p/2) rω2xcos(θ+24
0 +180 +30) F rec3' =
(old/2) (sp/2) r oo2
xcos(θ+120 +180 -30), and the inertial force in two directions becomes Frec1' + Frec3' = 0, which naturally balances out.

Next, the longitudinal inertia couple due to this force in the Z direction is Frec1'-S+Frec3'(3+21>
= (Jj/2) l1lpr ω21-sinθ
□, which matches the formula (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 reciprocating quality (■) on the crankshaft, the balance of inertial force by the counterweight, and the longitudinal inertia couple, that is, whirling, but here we will learn about the longitudinal couple horns of equations (1) and (3). and when we synthesize this, we get -5mpr ω21 sinθ0(IN /2) m
pr ω2xl-(sin θ-CO3θ) --(Ji/2) n+pr oo2 L (sin
θ+cosθ) (4) Therefore, how to balance such a longitudinal couple on the balancer shaft side will be explained with reference to FIG. First, on the balancer shaft 1, the balancer 8 corresponding to each cylinder is
If you half balance with a, 8b, and 8c,
The mass of each balancer 8a to 8G is mp/2 relative 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 8b 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 at a position shifted by 180 degrees from the position of 120 degrees counterclockwise.

Therefore, the force F in two directions when moving by θ from this state
recl, F rec2. Frec3 is Fre
al-(mp/2) r oo2 cos (
θ+240 +180 ) Frec2= (+e
p/2) r ω2 cos (θ+180)
F rec3= (mp/2) r oo2 c
os (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 (Jj/2>aprω2−Lsinθ−−−(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 longitudinal couple around the 7 wheels due to this Y direction force is (j'j/2) mpr
ω2Laosθ...(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 the Z direction and around the two axes in the Y direction, and the combined force is the above. The equations (2a') and (2b') give the following equation.

(j'j/2>ml)rω2L (sinθ+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. And the mass of the balancer 8σ corresponding to the third cylinder is II+
)/2 multiplied by 5/2, the one corresponding to the first cylinder is further advanced in phase by 30 degrees, and the one corresponding to the third cylinder is positioned further behind by 30' phase. This allows the fifth
You can replace it with the same result as in the diagram.

As mentioned above, the balance of inertial force by the balancer on the balancer shaft side,
and an explanation of the inertia couple in the longitudinal direction, and the result is equation (4'). Therefore, when this equation (4') is combined with the previous equation (4), it becomes zero, and from this, the longitudinal inertia due to the reciprocating mass generated on the crankshaft side and the mass of the counterweight that half-balances it. 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
l, Fc2. Fc3 is as follows.

Fc1=+acr w2 cos (θ+240
)Fc2=racr oo2 cos θFc
3=mcr w2 cos (θ+120) As a result, the eldest couple around the Y axis due to the rotating mass is -5mc
r oo2 Lsin θ −−L (
5a) The longitudinal couple around the two axes becomes JNmcr ω2LCOSθ ---(5b), which similarly occurs around the Y-axis due to the 7 directions and around the Z-axis due to the YF3 direction, and when combined, the following is obtained. become.

−Jjn+cr ω2 L (sin θ−cos
θ) −−′ −(6) Next, a counterweight 6a balances this rotating mass at 1 = 1 for each cylinder.
To explain the balance by the masses of 6c to 6c, it is the same as the configuration shown in FIG. F rot3 is as follows.

Frotl=scr ω2 cos (θ+240
+180) Frot2=icr ω2 cos (
θ+180)F rot3=a+cr (Z)2CO5
(θ+120 +180) As a result, the eldest couple around the Y axis in two directions is fimcr O2L sin
θ --- (7a) The longitudinal couple around the Z axis due to the Y direction is -Hricr O21-cos θ , (7b), and the whirling that is a combination of both is as follows.

Moon tear oo2 L (sin θ-cos
θ) --(8) By the way, also in the case of such a rotating mass, as shown in Fig. 4, the mass is tic<5/2)
By multiplying by 30' and advancing or delaying the 30' phase, it is possible to separate and concentrate the counterweights on the first and third cylinders.

Thus, regarding the rotating mass, the combined whirling longitudinal couple around the Y-wheel and Z-axis in equation (6) becomes zero by combining with the similar longitudinal couple in equation (8) due to the counterweight, and the two 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
Counterweights 5j-1 and ef-2 are provided at these locations, and counterweights 6σ-1+60'-2 are provided at two locations corresponding to the crank arms 2cm1 and 2C-2 in the third cylinder as well. Further, on the balancer shaft 7, as shown in FIG. 5, balancers 8a and 8b are installed at the portions corresponding to all of the first to third cylinders, particularly at the portions corresponding to the crankshaft bearings 9a and 9d in the first and third cylinders, respectively. , 8c is provided.

Two counterweights 6ai'-L of the crankshaft 1.

The ratio of the masses of the weights 6-2 does not necessarily need to be equal, and can be arbitrarily determined by simply changing the position of the combined center of gravity, and the same holds true for the other two counterweights 6σ-1° and 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 of each cylinder side ((I
I)/2) Juen 1 (IT/2), 30°
All you need to do is adjust the phase, so if the pitch of each cylinder is L as in Figure 2, then for the longitudinal couple: ((111+)/2) Juku) (5/2)
X2 L-(Takumi/2) 1Ill) L+j's
It is sufficient to generate +cl-.

Therefore, if the combined mass of the counterweights Fi -1 and d-2 is MCa', and the combined mass of the counterweights 6σ-1 and 6-2 is MCC', then considering the balance of the inertial forces on the crankshaft 1, So, M ca' = M cc'
need to be retained.

Then, the composite center of gravity position of counterweight 6Lx+Bza-2 is l+X, counterweight fli('-z, 6σ
-2's composite center of gravity is L+V, then Mca'(=Mcc') x (Sat+X+L+1
/)=(J'N/2) mpL +Jji+cL, so 1ylca' = M(C' = ((Jj/2) l
! lpL+j'jmcL)/<21+x-1-y
)...(9).

Here r X= y=o, that is, counterweight 68'-
If the composite center of gravity position of 1°6-2 and 6σ-1, 6σ-2 is made to match the pitch of each cylinder, the mass Mca',
MCC' is (Ji/4) mp+ (IN/2)
It becomes sc. Also, since x and y can be arbitrarily determined,
The larger the value and the farther apart the center of gravity is, the more the mass Mca
', Mcc' can be small.

Next, in the balancer shaft 1, as is clear from the above explanation, there is only the mass of the reciprocating part of the engine, and i
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
Let bb and Mbc be the center of gravity of the balancers 8a and 8c relative to the central balancer 8b, and let x' and y' be the center of gravity of the balancers 8a and 8c.
Considering the balance of inertial force on the balancer axis, Mba=M
Maintaining bb=Mbc
It is sufficient to take the Y-direction component of 8c and satisfy the following equation.

(Mba(L+x') +Mbc(L+y')
))XCO830=(month/2)+mpL That is, Mba=Mbb=Mbc=mpL/2 (L +
)...ω) Therefore, the center balancer 8b does not need to be aligned with the center of the second cylinder, but the balancer mass can be made smaller by separating the positions of each balancer and adjusting the value of C×'. In this case, the balancers 8a and 8c are the bearings 9a and 8c of the crankshaft 1, respectively.
Since it is arranged in a portion corresponding to 9d, the mass can be reduced and the space can be used effectively.

From this, in the crankshaft 1, the mass of 1 cylinder weight 6a-t, 6clf-2 on the first cylinder side and the counterweight 6σ-1, sC'-2 on the third cylinder side with the composite center of gravity position is calculated. Both satisfy equation (9), and the counter and weight are six pieces.

The position of u-2 is on the opposite side from the crank pin, and the phase is advanced by 30'', and the position of counterweights 6σ-, , 6C'-2 is on the opposite side from the crank pin, and the phase is delayed by 30 degrees, and both are connected to the crank arm 2b of the second cylinder. Position it at right angles to the

In the balancer shaft 7, the central balancer 8b is connected to the second cylinder equivalent part 1. The balancers 8a, 8c on both sides are connected to bearings 9a, 9.
At the position of the portion corresponding to d, half balance is achieved by the mass that satisfies equation (1), and as a result, the inertial force and couple due to the masses of the reciprocating portion and rotating portion of the three-cylinder engine are balanced.

Also, the balancer 8a corresponds to the crankshaft bearing.

8C is configured to also serve as a bearing, which is described in detail in FIG. It is assembled by fitting into the common shaft support 22 with the intermediate bearing 9a. Balancer 8G is configured in exactly the same way, and bearing 9
As a result, the balancer shaft 7 is rotatably supported on both sides by the bearings 23 of the above-mentioned configuration in the balancers 8a and 8c, and no other bearings are required. be. By the way, the balancer 8b in the center is placed in the part corresponding to the second cylinder, but since this second cylinder has no counterweight and only the crank arm 2b and has a small turning radius, there are restrictions on the installation of the balancer 8b. It becomes possible to move the balancer shaft 7 closer to the crankshaft side within a range where there is less interference and it does not interfere with the crank arm 2b.

Since it is balanced, there is very little vibration.

Since the balancers 8a and 8Ctfi are provided in the portions of the balancer shaft 1 corresponding to the crankshaft bearings 9a and 9d, the space can be used effectively and the balancer installation is advantageous. The balancer shaft 7 can be brought closer to the crankshaft 1 side due to the relationship between the central balancer 8b and the crank arm 2b of the second cylinder, contributing to miniaturization, and further reducing the distance between the balancers 8'a and 8c. Therefore, its mass can be reduced.

Since the balancers 8a and 8c are made with built-in bearings and also serve as bearings for the balancer shaft 7, the bending moment applied to the balancer shaft 7 is reduced, making it possible to reduce the balancer shaft diameter. is possible in terms of strength and reliability. Providing the bearing of the balancer shaft 7 in the bearing-equivalent parts of the crankshaft bearings 9a, 96, etc. is a highly rigid part of the engine, and can prevent problems caused by elastic vibration of the engine due to repeated loads. Furthermore, even in cases where the balancer shaft 7 is partially submerged in oil due to the mounting position of the engine, the balancers 8a and 8c are housed in the entire circumferential shaft tube 20. It can prevent blowouts, etc.

In this case, the central balancer 8b can also be equipped with a shaft tube.This further increases the effect of preventing the oil I well resistance from increasing as described above.

A specific example of the balancer shaft installation will be explained with reference to FIG. 9. When the engine is mounted under the loading platform using the R-R method as shown in the figure, the engine body 10 is restricted by the loading platform 16 and is placed in a vertical position. It is installed at a considerable angle from the
On the engine body 10 in such a posture, an air cleaner 11, a carburetor 12, an intake system including an intake pipe 13, a cooler compressor 14, an AcG 15, etc. are arranged. Therefore, the upper part of the engine body 1o is limited by the above-mentioned various auxiliary equipment, and when the balancer shaft 1 is installed downward as shown in the figure, the balancer shaft 7 is located below the crankshaft 1 and partially It is immersed in oil, and the effect of the present invention described in 1-1 is exhibited when it is soaked.

[Brief explanation of drawings]

1 to 6 are explanatory diagrams for explaining the present invention in detail,
FIG. 7 is a schematic diagram showing an embodiment of a balancer device for a three-cylinder engine according to the present invention, FIG. 8 is a sectional view showing a specific example of the main parts, and FIG. FIG. 3 is a side view showing a specific example. 1... Crankshaft, 2, 2a, 2J 2c, 2
a-1, 2a-2. 2cm1, 2cm2°°゛Crank arm, 6,6 za-1
, 6 za-2, 6 ['-1゜6σ-2... Counterweight, 7... Balancer shaft, 8° 8a, 8c... Balancer, 9a, 9d... Bearing, 20... Axial tube, 2
1...metal, 22.24...shaft support, 23...
bearing. Patent Applicant Fuji Heavy Industries Co., Ltd. Representative Patent Attorney Jundo Kobashi Patent Attorney Susumu Murai Figure 4 2

Claims (1)

[Claims] On the crankshaft, in which the crank arms are sequentially arranged at equal intervals of 120 degrees, on the opposite side of the crank pin of the crank arms of the first and third cylinders, a predetermined position is placed at an i angle with the crank arm of the second cylinder. Provide a counterweight for the mass,
Rotating in the opposite direction at the same speed with respect to the above crankshaft 1
A main balancer shaft is provided, and on the balancer shaft, three parts corresponding to the crankshaft bearings of the first and third cylinders and a part corresponding to the second cylinder are provided.
A balancer device for a three-cylinder engine, characterized in that a balancer of a predetermined mass is provided at a location so as to provide half balance, and the balancers of the portions corresponding to the crankshaft bearings of the first and third cylinders are also used as bearings.