JPS6145091B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a balancer device for a four-cylinder 90° crank type reciprocating engine, which simultaneously eliminates vibrations in two directions due to pitching moment and yawing moment.

Incidentally, in the crankshaft of an internal combustion engine, vibrations are reduced or eliminated by providing a balance weight, but the balancing by this balance weight is performed by four cylinders with crank pins arranged at 90° intervals. When analyzing a crank-type engine, first take the coordinate axes X, Y, and Z as shown in Figure 1, determine the phase of the crank in each cylinder as shown in Figure 2, and determine the rotating parts of each cylinder (crank pin, The mass of the crank arm, etc.) is m _O , the mass of the reciprocating part (piston, piston pin, etc.) is m _P , the mass of the balance weight is m _B , the crank radius is r, the effective radius of the balance weight is r _B , and the crank If the angular velocity of the shaft is ω and the distance between the cylinders is L _O , then () the moment around the Y axis due to the rotating part M _OY
As shown in Fig. 2, the Z-direction component of the force acting on the rotating part of each cylinder is: 1st cylinder: m _O rω ² cosθ 2nd cylinder: m _O rω ² cos (θ + 270°) 3rd cylinder: m _O rω ² cos (θ+90°) Fourth cylinder: m _O rω ² cos (θ+180°), so M _OY = m _O rω ² cosθ×3/2L _O + m _O rω ² cos (θ+270°)×1/2L _O −m _O rω ² cos(θ+90°)×1/2L _O −m _O rω ² cos(θ+180°)×3/2L _O =m _O rω ² L _O (3cosθ+sinθ) =√10m _O rω ² L _O cos( θ−θ ₀ ) (1). Here, tanθ ₀ =1/3 and θ ₀ =18°26′. Similarly, the moment M _OZ around the Z-axis due to the rotating part is M _OZ = m _O rω ² sin θ × 3/2L _O + m _O rω ² sin (θ + 270°) × 1/2 L _O − m _O rω ² sin ( θ+90°)×1/2L _O −m _O rω ² sin(θ+180°)×3/2L _O =m _O rω ² L _O (3sinθ−cosθ) =√10m _O rω ² L _O sin(θ−θ ₀ ) (2) becomes.

() Next, the moments M _PY and M _PZ around the Y and Z axes due to the reciprocating part are calculated as in () as follows: M _PY =√10m _P rω ² L _O cos (θ−θ ₀ ) (3) , in this case, M _PZ =0 (4) because no moment is generated around the Z-axis depending on the reciprocating portion.

() Furthermore, the moments M _BY and M _BZ due to the balance weights are calculated by the mass m _O in () being replaced by m _B , the radius r being replaced by r _B , and 180° between the masses m _O and m _B in each cylinder. Since _{there is} ^{a phase} _{difference of}
(5) M _BZ = -√10m _B r _B ω ² L _O sin (θ−θ ₀ ) (6).

Therefore, the sum of the moments from each of these parts becomes the pitching moment and yawing moment of the entire engine, and if these are M _Y and M _Z , then equations (1), (3), and (5) are obtained. From M _Y = M _OY + M _PY + M _BY = √10L _O ω ² cos (θ−θ ₀ ) (m _O r+m _P r−m _B r _B ) (7) Also, (2), (4), (6 ) From the formula, M _Z = M _OZ + M _PZ + M _BZ = √10 L _O ω ² sin (θ−θ ₀ ) (m _O r−m _B r _B ) (8). From these two equations, when designing the balance weight, if m _B r _B = m _O r + m _P r, then M _Y =0
(This state is called 200% balance), the pitching moment can be removed, and m
If _B r _B = m _O r, then M _Z = 0 (this state is 100%
Although it is possible to eliminate the yawing moment by reducing the balance (called balance), it turns out that it is impossible to eliminate both at the same time.

Therefore, in the past, 100% balance and 200%
The balance weight was designed to be in the most suitable state for the installation conditions of the engine in the middle of the balance, but in that case the vibrations due to both moments would remain.
In the case of a 180° crank, it has been devised to remove both moments using a balancer shaft, but this method requires an extremely complicated device, significantly increases costs, and has the disadvantage that it cannot be applied to a 90° crank.

The present invention was made in view of the above circumstances, and in a four-cylinder 90° crank type engine, the balance weight is set to 100% balance, which eliminates the yawing moment, and a predetermined mass is set for the reciprocating portion of a predetermined cylinder. By adding or reducing the weight and equipping the crankshaft with a balance gear having an eccentric mass corresponding to the mass, a couple is generated that cancels out the pitching moment caused by the reciprocating part, resulting in a relatively simple configuration. This system simultaneously removes both pitching and yawing moments and prevents vibrations caused by them.

This will be explained below using an example shown in the figure.
In Fig. 3, 1 is the crankshaft, 2 ₁ , 2 ₂ , 2
₃ and ₂₄ are four crank pins having the phase relationship shown in Fig. 2, and each pin has a connecting rod 3.
Pistons ₄ 1 , ₄ via ₁ , 3 ₂ , 3 ₃ , 3 4
₂ , 4 ₃ , 4 ₄ are connected, and each of the above pins
On the opposite side of 180°, there are balance weights 5 ₁ , 5 ₂ ,
5 ₃ and 5 ₄ are attached respectively. 6 is a balance gear fixed to one end of the crankshaft, 7 is another balance gear paired with this as shown in FIG. 4, and eccentric weights 6a, 7 are located at corresponding positions of both gears.
a is provided, and 8 ₃ and 8 ₄ are weights added to the pistons 4 ₃ and 4 ₄ in the third and fourth cylinders, respectively. Here, if the mass of the weight ₈₃ added to the piston ₄₃ of the third cylinder is Δm _P , then the piston 4 of the fourth cylinder
The mass of the weight ₈₄ added to the weight ₈₄ is 3Δm _P. Therefore, the forces F ₃ and F ₄ acting on both weights are F ₃ =Δm _P × rω ² and F ₄ = 3Δm _P rω ² , respectively. The resultant force F is F=√10Δm _P rω ² by combining the vectors shown in FIG. 5, and the phase is θ+180° _−θ0 . On the other hand, if the mass of the eccentric weights 6a and 7a in the balance gears 6 and 7 is m _G and its effective radius is r _G , then the force acting on the weights is
m so that F′=2m _G r _G ω ² balances the resultant force F above.
_G and r _G are determined to satisfy 2m _G r _G =√10Δm _P r (9).

However, a force couple is generated by the Z-direction components of the forces F and F', which are equal in magnitude and opposite in direction, but the moment acts around the Y-axis, and if this is ΔM _Y , then the force F, Letting the distance between the points of action of F' be L, ΔM _Y =√10Δm _P rω ² cos (θ+180°−θ ₀ )×L=−√10Δm _P rω ² cos (θ−θ ₀ )×L(10). , this moment is added to the pitching moment M _Y mentioned above. Therefore, the pitching moment of the entire engine is
From formulas (7) and (10), M _Y = M _OY + M _PY + M _BY + ΔM _Y = √10ω ² cos (θ−θ ₀ ) × {(m _O r + m _B r _B ) L _O + (m _P L _O − Δm _P L)r} (7)′, and the yawing moment remains unchanged, M _Z =√10L _O ω ² sin(θ−θ ₀ )(m _O r−m _B r _B ) (8).

Therefore, when designing the balance weights 5 ₁ to 5 ₄ , m _B r _B = m _O r, that is, 100% balance, and the weights 8 ₃ ,
The mass Δm _P of 8 ₄ , 3Δm _P is set to satisfy Δm _P L = m _P L _O , and the pitching moment M _PY due to the reciprocating part is set to be canceled by _ΔMY , and the balance that satisfies equation (9) is established. If gears 6 and 7 are installed, M _Y =M _Z =0 from equations (7)' and (8), and pitching moment and yawing moment will be removed at the same time.

In addition, as mentioned above, the piston 4 ₃ of the third cylinder
A weight ₈₃ of mass Δm _P is added to , and the fourth
Instead of adding a weight 84 with a mass of _3ΔmP to the piston _{44 of} the cylinder, the mass _3ΔmP is reduced from the piston ₄₁ of the first cylinder, and the second
It is also possible to reduce the mass Δm _P from the piston ₄₂ of the cylinder. In short, it is sufficient to add or reduce the mass so that the force F shown in FIG. The further away from the gear, the less mass needs to be added or removed. Also, instead of adding weights 6a and 7a to balance gears 6 and 7, 180
゜It is the same even if the mass is reduced in the opposite direction. Furthermore, the addition or reduction of mass in the piston may be carried out in reciprocating parts other than the piston, such as the piston pin or the small end of the connecting rod, and if a reduction gear or the like is connected to the engine, the mass of the reduction gear or the like may be added or reduced. A balance gear may be installed inside.

As described above, according to the balancer device of the present invention, in a four-cylinder 90° crank type engine, the balance by the balance weight of the crankshaft is set to 100% balance, and a predetermined mass is applied to the reciprocating part of the piston, etc. in a predetermined cylinder. Vibrations in two directions based on pitching moment and yawing moment can be removed at the same time with a simple configuration of adding or subtracting and equipping the crankshaft with a pair of balance gears, which can significantly increase costs, etc. This has the effect of realizing a quiet engine with less vibration and noise. Note that the present invention is not limited to internal combustion engines;
It is clear that the present invention can also be applied to air compressors and the like.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of coordinate axes used to explain the present invention, Fig. 2 is an explanatory diagram of the phase relationship, Fig. 3 is a schematic front view of an embodiment of the present invention, and Fig. 4 is a balance gear in Fig. 3. The side view of FIG. 5 is an explanatory diagram of the couple in the present invention. 1 is the crankshaft, 4 ₁ to 4 ₄ is the piston, 5 ₁
~ ₅₄ is a balance weight, 6 and 7 are balance gears, 6a and 7a are eccentric weights, and ₈₃ and ₈₄ are weights added to the piston.

Claims (1)

[Claims] 1. In an in-line four-cylinder engine with crank pins arranged every 90 degrees, the balance weight of the crankshaft is set to approximately 100% balance, and a predetermined mass is added or reduced to the reciprocating portion of a predetermined cylinder, and the crankshaft is A balancer device for a reciprocating engine, which is equipped with a pair of balance gears having an eccentric mass corresponding to the mass, and these masses generate a couple that offsets the pitching moment due to the reciprocating portion of each cylinder.