JPS6154975B2 - - Google Patents

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a primary balancer device for a 4-stroke series two-cylinder engine, and relates to a balancer device for eliminating not only the primary excitation force but especially the primary excitation moment. It is related to the device.

[Conventional technology]

JP-A-50-82409 proposes a pair of balancers to reduce the secondary excitation force and secondary excitation moment caused by the reciprocating mass.
In addition, in order to remove the inertia force caused by reciprocating motion and reduce engine vibration, the mass of the reciprocating part is 1/1
The unbalance amount equivalent to 4 is installed on each balancer shaft in the same phase, as described in the publication "Internal Combustion Engine".
Described in Vol.15, No.185, 1976/10.

[Problem that the invention seeks to solve]

By the way, when comparing the excitation force and moment of an in-line 2-cylinder engine and an in-line 4-cylinder engine with the same displacement, the first-order component of the in-line 2-cylinder engine is considerably larger than that of an in-line 4-cylinder engine. When the component becomes more than 2nd order, the series 2
A cylinder engine is almost equivalent to an in-line 4 cylinder engine. Therefore, in an in-line two-cylinder engine, it is considered sufficient if the first-order components can be balanced.

Additionally, with the balancer device described in the publication "Internal Combustion Engine," it is possible to remove the primary excitation force (inertia force), but there is a problem in that it is impossible to eliminate the primary excitation moment. .

[Means for solving problems]

In order to achieve the above object, the present invention provides two balancer shafts parallel to the crankshaft,
Both balancer shafts are configured to rotate in the opposite direction to the crankshaft at the same speed as the crankshaft, a weight is attached to each balancer shaft, the phase of the weight of the crankshaft with respect to the crank pin is π, and the moment of each balancer is Among the eight elements m ₁ r ₁ , m ₂ r ₂ , phases α ₁ , α ₂ relative to the crank pin, and positions ξ ₁ , ξ ₂ , ζ ₁ , ζ ₂ of the balancer shaft, the four elements including at least two position elements are After setting the conditions, find the remaining four elements from the formula so that the primary excitation force and moment are zero at a specific rotation speed and load, and calculate the position of each balancer shaft relative to the crankshaft and the position of each balancer. It is configured to set the moment and the phase with respect to the crank pin, respectively.

[Effect]

Based on the above configuration, the present invention can reduce the primary excitation force and excitation moment to zero at a specific engine speed and load, and the position of the balancer shaft relative to the crankshaft and the moment and moment of each balancer. It becomes possible to set the phase with respect to the crank pin.

〔Example〕

The present invention will be explained below with reference to the drawings for a two-cylinder engine with equally spaced explosions.

Now, let us consider the vibration moment that occurs when N primary balancer shafts are provided. In Figure 1, O is the crankshaft, Q is the i-th balancer shaft, the axial direction of the crankshaft is Y, the cylinder axis direction is Z, and the direction perpendicular to these is X, and the force acting on the engine body and The moment will be explained below. Each code used in the explanation is as follows.

m: Reciprocating mass (total of 2 cylinders) r: Crank radius l: Rod length λ=l/r θ: Crank angle ω: Crank angular speed m ₀ : Rotating mass (total of 2 cylinders) M ₀ : Weight attached to the crank Mass θ ₀ : Phase of M ₀ with respect to θ ξ _i : Position of X coordinate of i-th balancer axis ζ _i : Position of Z coordinate m _i : Mass of weight r _i : Radius α of center of gravity of m _{i i} : Phase of m _i with respect to k _i θ k _i : 1 when the i-th balancer shaft rotates at the same time as the crank, -1 when it rotates in the opposite direction N: Number of balancer shafts Force and moment acting on the engine body When written as a formula, it becomes as follows.

a Vibrational force due to the reciprocating mass (Z-axis direction) Frec=-mα Here, α is the acceleration of the reciprocating mass, as shown in the following formula.

α=−rω ² (cosθ+C ₂ cos2θ+…) C ₂ = (1/λ) + (1/4λ ₃ )+… b Excitation force due to rotating mass (radial direction of rotation) f ₀ = m ₀ rω ² c Vibratory force due to the weight attached to the crankshaft (radial direction of rotation) F ₀ = M ₀ rω ² d Exciting force due to the weight attached to the balancer shaft (radial direction of rotation) The primary component in the X and Z directions due to the above force is F
When _x and F _z are taken, it becomes as follows.

Moment is a value around the crankshaft, with clockwise rotation being positive.

e Excitation moment due to inertia of reciprocating mass Mrec=・Frec tanψ=(1/2)mr ² ω ² (D ₁ sin ₁ θ +2D ₂ sin2θ+…) D ₁ =−(1/2λ)−(1/8λ ³ ) −…… D ₂ = (1/2) + (1/32λ ⁴ ) +…… f Excitation moment due to the force of gas pressure Mgas =・(−Fgas tanψ) = −(V/2) (a ₁ cos θ + b ₁ sin θ + a ₂ cos 2 θ + b ₂ sin 2 θ +...) As a result of Fourier analysis, it can be seen that a ₁ , b ₁ , a ₂ , b ₂ ... are almost proportional to the load regardless of the rotation speed. V is the displacement.

g Excitation moment due to inertia of the weight attached to the balancer shaft Let My be the moment of the Y-axis rotation of the sum of the primary components of the moments e to g above.

My=−(mr ² ω ² /4λ) sinθ −(v/2) (a ₁ cosθ+b ₁ sinθ)
+M _bal ...(3) As a balancer, each condition may be determined so that the above equations (1), (2), and (3) become zero. In order to install a balancer axis in any position and make it zero for all θ, if the number of balancer axes is one, there are many conditions that cannot be determined and it is unsuitable.Therefore, a two-axis balancer device is used. is preferable. In the case of a two-axis balancer device, the following equations must be satisfied in order to make each of the above equations zero.

k ₁ = −1 (4) k ₂ = −1 (5) θ ₀ = π (6) Mor−mor=mr/2 (7) m ₁ r ₁ cosα ₁ + m ₂ r ₂ cosα ₂ = −mr/2 (8) m ₁ r ₁ sinα ₁ +m ₂ r ₂ sinα ₂ = 0 (9) −ξ ₁ m ₁ r ₁ ω ² cosα ₁ +ζ ₁ m ₁ r ₁ ω ² sinα ₁ −ξ ₂ m ₂ r ₂ ω ² cosα ₂ +ζ ₂ m ₂ r ₂ ω ₂ sinα ₂ +A=0 (10) k ₁ ξ ₁ m ₁ r ₁ ω ² sinα ₁ +k ₁ ζ ₁ m ₁ r ₁ ω ² cosα ₂ +k ₂ ξ ₂ m ₂ r ₂ ω ² sinα ₂ +k ₂ ζ ₂ m ₂ r ₂ ω ² cosα ₂ +B=0(11) However, A and B are the cos and sin components of the excitation moment generated by an engine without a balancer, respectively, and are unique to the engine. It is determined by the value of , rotation speed and load.

In the above formula, m and r are unique to the engine, and if A, B, and ω are also given as constants, the magnitude of the balancer moment: m ₁ , r ₁ ,
m ₂ , r ₂ The phase of the balancer with respect to the crank: α ₁ , α ₂ The position of the balancer axis: ξ ₁ , ξ ₂ , ζ ₁ , ζ ₂ These are the values that determine the eight balancers.

Among these eight quantities, (m ¹ r ₁ , m ₂ r ₂ , α ₁ ,
α ₂ ) is a and (ξ ₁ , ξ ₂ , ζ ₁ , ζ ₂ ) is b
Then, equations (8) and (9) are the relationship of a, and equations (10) and (11) are functions of a and b.

Therefore, if b(ξ ₁ , ξ ₂ , ζ ₁ , ζ ₂ )
Once determined, equations (8) to (11) become a(m ₁ r ₁ , m ₂ r ₂ , α
₁ , α ₂ ), and by solving a one-dimensional four-dimensional simultaneous equation, the values of m ₁ r ₁ , m ₂ r ₂ , α ₁ , and α ₂ can be obtained. That is, by determining the position of the balancer axis, the magnitude and phase of the balancer's moment are determined.

Also, if any three of b and any one of a are determined, equations (8) to (11) each become the remaining four simultaneous equations, and by solving them, 4
values can be obtained.

Furthermore, if any two of a are determined, (8), (9)
The remaining two pieces of a are determined from the formula. Also, of b,
Once any two items are determined, the remaining two items of b are determined.

Therefore, by determining any four of b including at least two, it is possible to determine the amount of eight required as a balancer. By configuring the balancer device in this way, the excitation moment becomes zero at a specific load and rotational speed, and the excitation force becomes zero at all load rotational speeds.

Figure 2 is a chart obtained by substituting the following numerical values into the conditional expression for an example of a 4-cycle in-line 2-cylinder engine, where My = 5000 rpm and road load.
It is set to be 0.

Mor−mor＝0.5mr α ₁ =182.76゜m ₁ r ₁ =0.294mr α ₂ =176.06゜m ₂ r ₂ =0.207mr A/g=-2.81 (Kg・m) B/g=−9.94 (Kg・m) ξ ₁ = 0.0763 (m) ξ ₁ = 0.0477 (m) ξ ₂ = -0.0851 (m) ξ ₂ = -0.0090 (m) m = 0.819 (Kg) r = 0.03 (m) l = 0.11 (m) However, g is gravitational acceleration.

The thick lines in the figure are equal moment diagrams showing moment curves, and the thin lines are diagrams showing the relationship between the engine speed and indicated horsepower depending on the load. It can be obtained in the same way at other rotation speeds, but in the case of this engine, when the rotation speed is set to 5000 rpm and matched to the road load, 0≦My≦5
It was found to be practical as it has a wide range and covers a wide range of areas where engines are put into practical use.

In other words, the balancer can be designed by determining which operating conditions the vibration moment My of the entire engine should be matched with in accordance with the characteristics of the engine to minimize vibration within a practical range.
It is also possible to apply it to a one-cylinder engine.

〔Effect of the invention〕

As is clear from the above, according to the present invention, the phase of the weight provided on the balancer shaft with respect to the crank pin and the position of the balancer shaft can be set respectively, so there is a large degree of freedom in design, and the arrangement of engine auxiliary equipment is possible. In addition, by matching the vibration moment of the entire engine under specified operating conditions according to the characteristics of the engine, it is possible to effectively utilize the narrow engine room. The vibration can be minimized, and it can also be applied to a one-cylinder engine.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram for explaining the present invention, Fig. 2 is a schematic diagram for explaining the present invention;
The figure shows a first-order homogeneous excitation moment around the crankshaft, and FIG. 3 is a diagram showing the case of FIG. 1 with two balancer shafts.

Claims (1)

[Claims] 1. Two balancer shafts are provided parallel to the crankshaft, and both balancer shafts are configured to rotate in the opposite direction to the crankshaft at the same speed as the crankshaft, and each balancer shaft is provided with a weight. is installed, the phase of the weight of the crankshaft with respect to the crank pin is π, the moment of each balancer is m ₁ , r ₁ , m ₂ , r ₂ , and the phase of each balancer with respect to the crank pin is α ₁ , α
_2. Position ξ of each balancer shaft relative to the crankshaft
Among the eight elements ₁ , ξ ₂ , ζ ₁ , and ζ _2, four elements including at least two position elements are set as conditions, and the remaining four elements are used to determine the primary excitation force and primary excitation force at a specific rotation speed and load. The following relationship is established so that the excitation moment is zero: m ₁ r ₁ cosα ₁ + m ₂ r ₂ cos α ₂ = −mr/2 m ₁ r ₁ sin α ₁ + m ₂ r ₂ sin α ₂ = 0 −ξ ₁ m ₁ r ₁ ω ² cosα ₁ +ζ ₁ m ₁ r ₁ ω ² sinα ₁ −ξ ₂ m ₂ r ₂ ω ² cosα ₂ +ζ ₂ m ₂ r ₂ ω ² sinα ₂ +A=0 k ₁ ξ ₁ m ₁ r ₁ ω ² sinα ₁ +k ₁ ζ ₁ m ₁ r ₁ ω ² cosα ₁ +k ₂ ξ ₂ m ₂ r ₂ ω ² sinα ₂ +k ₂ ζ ₂ m ₂ r ₂ ω ² cosα ₂ +B=0, where m: reciprocating mass r: crank Radius ω: Crank angular velocity _k1 , _k2 : -1 when each balancer shaft rotates in the opposite direction to the crankshaft A, B: So as to satisfy the cos and sin components of the excitation moment generated by an engine without a balancer, respectively. , The position of each balancer shaft with respect to the crankshaft, the moment of each balancer and the phase with respect to the crank bin are set respectively, each balancer shaft is set at the set position, and each weight is set on each balancer shaft. This is a primary balancer device for a 4-stroke series engine.