KR20020037935A - An unbalenced inertia couple force reducing structure of 3-cylinder engines - Google Patents

Abstract

PURPOSE: Structure for reducing the unbalance couple force of a three-cylinder engine is provided to make a crankshaft and a piston unit form a complete balance by completely offsetting the secondary element of an unbalance couple force due to the reciprocating mass. CONSTITUTION: Six main balance weights(16a,16b,16c,16d,16e,16f) are formed on a crankshaft(14) installed in a cylinder block(12). Three balance shafts(18,20,22) are installed on the crankshaft. The first and second balance shafts includes two auxiliary balance weights(26a,26b,28a,28b) on both ends. The centers of the balance shafts are symmetric to the center of the crankshaft. The first and second balance shafts rotate by interlocking to the rotation of the crankshaft. By forming the inertia moments and phase values of the main balance weights and three balance shafts, the first and secondary elements of the unbalance couple force are removed.

Description

Unbalanced Inertia Force Reduction Structure for Three-cylinder Engines {AN UNBALENCED INERTIA COUPLE FORCE REDUCING STRUCTURE OF 3-CYLINDER ENGINES}

The present invention relates to an unbalanced inertia-force reduction structure of a three-cylinder engine, and more particularly, to an unbalanced inertia-power of a three-cylinder engine that enables full mechanical equilibrium of the crankshaft and piston mechanism in a three-cylinder engine. It relates to a reduction structure.

The internal combustion engine is composed of a mechanical structure in which power is generated by the piston reciprocating by the explosion pressure generated during combustion of the combustion chamber and thus rotating the crankshaft.

The internal combustion engine made of such a piston and crankshaft mechanism is different from the turbine type prime mover, and the inertial force of the moving part is not balanced, and the force caused by the combustion gas pressure is intermittent. For this reason, the excitation force transmitted to the engine mounting and the chassis is large and there is a periodic fluctuation of the torque, which frequently causes vibration in the crankshaft system.

To balance the inertia force and its inertia couple force due to the mass of the moving part of the piston and crankshaft mechanism is called the engine equilibrium, and the magnitude of the inertia force increases in proportion to the square of the engine rotational speed. In particular, it is important to consider the equilibrium.

In the case of a multicylinder engine, the cylinder arrangement and the shape of the crankshaft are determined in consideration of the balance of the inertia force.In this case, the condition for the completely equilibrium of the polycylinder engine is (1) that the inertia force due to the reciprocating and rotational motion is always zero. (2) The combined force of the inertia forces around any point of their inertia forces must always be zero. Here, the inertia force and the inertia force by the reciprocating motion are known to be practically sufficient considering the secondary term.

Such a mechanical method for balancing the engine is generally made to attach the balance weight to the crankshaft or additionally mount the balance shaft. In the case of a three-cylinder engine, as shown in FIG. 4, six balance weights are provided. A pair of (116a, 116b, 116c, 116d, 116e, and 116f) is installed in the crank web 114 of each crankshaft 112 at equal intervals of 120 °, and two balance weights 120a and 120b are provided. An unbalanced inertia due to rotational mass resulting from the mechanical relationship between the crankshaft 112 and the piston (not shown) is arranged by placing one balance shaft 118 mounted at both ends of the crankshaft 112 at one lower end thereof. It consists of a structure that compensates for the unbalanced inertia power due to the right and reciprocating masses.

However, the offset structure of the unbalanced force of the three-cylinder engine as described above consists of a structure capable of offsetting only the primary component of the unbalanced force due to the rotational mass of the crankshaft and the unbalanced force due to the reciprocating mass of the piston. The secondary component of the unbalanced power due to the stiffness was not properly removed and did not achieve full mechanical equilibrium in the three-cylinder engine.

Accordingly, the present invention is to solve the above problems, an object of the present invention is to offset all the secondary components of the unbalanced force by the reciprocating mass so that the crankshaft and piston mechanism of the three-cylinder engine can achieve a complete mechanical equilibrium To provide an unbalanced inertia-force reduction structure for a three-cylinder engine.

1 is a schematic diagram of a structure for reducing inertia of a three-cylinder engine according to the present invention;

2 is a first diagram illustrating an arrangement relationship between a balance weight and a balance shaft of the present invention;

3 is a second diagram illustrating an arrangement relationship between a balance weight and a balance shaft of the present invention;

4 is a schematic diagram of an inertia-running force reduction structure of a three-cylinder engine according to the prior art.

<Description of the symbols for the main parts of the drawings>

12 cylinder block 14 crankshaft

16a, 16b, 16c, 16d, 16e, 16f: Main balance weight

18, 20, 22: first, second, third balance shaft

24: Crank Web

26a, 26b, 28a, 28b, 30a, 30b: auxiliary balance weight

32a, 32b, 32c: crank pin

The present invention to achieve the above object

In a three-cylinder engine with three cylinder chambers,

Six main balance weights installed at equal intervals of 120 ° on each crank web of the crankshaft having six crank webs; First and second balance shafts each having two auxiliary balance weights mounted at both ends thereof, the center of the shaft being opposed to both sides with respect to the center of the crankshaft so as to be interlocked with the rotational movement of the crankshaft; And a third balance shaft mounted on two ends of the two auxiliary balance weights, the third balance shaft being interlocked with the second balance shaft.

The main balance weight and the first, second, and third balance shafts provide an unbalanced inertial force reducing structure of the three-cylinder engine, characterized in that made to offset the unbalanced inertia.

Hereinafter, with reference to the accompanying drawings an embodiment of the present invention that can specifically realize the above object will be described.

FIG. 1 schematically shows an unbalanced inertial force reducing structure according to a preferred embodiment of the present invention. Referring to this, the present invention relates to a crank shaft 14 mounted to a cylinder block 12 having three cylinder chambers. Unbalanced inertia-running force reduction structure of six main balance weights 16a, 16b, 16c, 16d, 16e, and 16f that are formed, and three balance shafts 18, 20, and 22 that are interlocked with the crankshaft 14 Is made of.

In the above, the main balance weights 16a to 16f are installed on the six crank webs 24 formed on the crankshaft 14 at equal intervals of 120 ° from each other, and the mass of each main balance weight 16a to 16f is Same value ( To form).

The first balance shaft 18 and the second balance shaft 20 of the balance shafts each have two auxiliary balance weights 26a, 26b, 28a, and 28b mounted at both ends thereof, and the centers of the shafts are cranked with each other. The shaft 14 is arranged to face left and right with respect to the axis center. Here, the first balance shaft 18 and the second balance shaft 20 are rotated in conjunction with the rotation of the crankshaft 14, the interlocking means as a gear coupling between each other or a pulley coupling using a chain or belt Method can be used.

The third balance shaft 22 has two auxiliary balance weights 30a and 30b mounted at both ends thereof, and is installed to be interlocked with any one of the first and second balance shafts 18 and 20. In the embodiment of the present invention, the second balance shaft 20 is coupled to be interlocked. Of course, although the third balance shaft 22 is linked to the first balance shaft 18, it is irrelevant. In this case, even if the first balance shaft 18 is equal to the crank shaft rotation speed, the third balance shaft 22 Is interlocked so as to be two of the rotational speeds of the crankshaft.

Meanwhile, the interlocking means of the second balance shaft 20 and the third balance shaft 22 may use a gear coupling or pulley coupling scheme in the same manner as described above.

The six main balance weights 16a to 16f and the three balance shafts 18, 20 and 22 made as described above, and by setting the moment of inertia and the phase value appropriately, The first and second components of the unbalanced force due to the reciprocating mass of the piston can be offset, which will be described in more detail as follows.

2 and 3 are schematic diagrams illustrating a crank shaft and a balance shaft in order to explain the arrangement relationship between the balance weight and the balance shaft according to the present invention, and FIG. 2 (a) shows the crank shaft 14. (B) illustrates the first balance shaft 18, FIG. 2 (c) illustrates the second balance shaft 20, and FIG. 2 (d) illustrates the third balance shaft 22. 3 illustrates the arrangement relationship between the respective balance weights.

2 and 3, M is the rotational mass, Is the reciprocating mass, R is the crank throw (where crank throw is the distance from the center of the shaft of the crankshaft 14 to the center of the shaft of the crank pins 32a-32c), P is the pitch between the cylinder bores, H is the distance between the auxiliary balance weights of the balance shaft, The mass of the main balance weights 16a to 16f, The mass of the auxiliary balance weights 26a and 26b of the first balance shaft 18, The mass of the auxiliary balance weights 28a, 28b, 30a, 30b of the second and third balance shafts 20, 22, Is the radius of the main balance weights 16a-16f, The mass of the auxiliary balance weights 26a and 26b of the first balance shaft 18, Is the radius of the auxiliary balance weights 28a, 28b, 30a and 30b of the second and third balance shafts 20 and 22, θ is the angle from the X axis to the first crank pin 32a, and α is the first crank pin. The angle from the 32c to the main balance weights 16a and 16b attached thereto, β is the angle from the first crank pin 32a to the auxiliary balance weight 26a on the front side of the engine of the first balance shaft 18, γ₁ is the angle from the first crank pin 32a to the auxiliary balance weight 28a on the engine front side of the second balance shaft 20, γ₂ is the engine of the third balance shaft 22 from the first crank pin 32a. Supposing the angle to the auxiliary balance weight 30a on the front side, the sum of the unbalanced inertia force and the unbalanced inertia force of the entire engine generated by this can be expressed as follows.

(Eq. 1)

In order to achieve equilibrium in Equation 1, each term must be zero, so the following identity is established.

(Eq. 2)

(Eq. 3)

(Eq. 4)

(Eq. 5)

Solving the above equations (2) to (5) gives the following results.

① α = 2n pi + pi, ② , ③

④ , ⑤

⑥ , ⑦

When the inertia moments and phase values of the main balance weight and the first, second, and third balance shafts are determined according to the values obtained as described above, first, the main balance weights 16a to 16f have their Inertia moment values below Equation (6) is satisfied, and the phase value of each main balance weight pair has a phase difference of? And crank pins therebetween.

Equation 6 Moment of Inertia (I ') = 0.5 × Rotational Mass (M) × Crank Through (R) + 0.25 × Reciprocating Mass ( Crank throw (R) where crank throw is the distance from the center of the crankshaft to the center of the crank pin.

Next, the first balance shaft 18 rotates in the opposite direction to the rotational direction of the crankshaft 14, has the same speed ratio as the rotational speed of the crankshaft 14, and the auxiliary balance weights 26a and 26b at both ends thereof. The inertia moment value satisfies Equation 7 below, the phase value of the auxiliary balance weight 26a on the front side of the engine has a phase difference of 7π / 6 with the first crank pin 32a, and the auxiliary balance on the rear side of the engine. The phase value of the weight 26b is to have a phase difference of pi with the phase value of the auxiliary balance weight 26a on the front side of the engine.

Equation 7 Moment of Inertia (I₂) = 0.433 × reciprocating mass ) Crank throw (R) x distance from center of first cylinder bore to center of third cylinder bore (L) / distance between auxiliary balance weights (H).

The second balance shaft 20 rotates opposite to the rotational direction of the crankshaft 14, has a rotational speed ratio twice the rotational speed of the crankshaft 14, and auxiliary balance weights 28a and 28b at both ends thereof. ), The moment of inertia meets (8) below, and the phase value of the auxiliary balance weight 28a on the front side of the engine has a phase difference of 5π / 6 with the first crank pin 32a. The phase value of the auxiliary balance weight 28b has a phase difference of π with the phase value of the auxiliary balance weight 28a on the front side of the engine.

(8) Moment of Inertia (I₃) = (0.108 / λ) x reciprocating mass ( ) Crank throw (R) x Distance from the center of the first cylinder bore to the center of the third cylinder bore (L) / Distance between auxiliary balance weights (H)-where λ = crank throw (R) / connecting rod Length (l).

Finally, the third balance shaft 22 rotates in the same direction as the rotational direction of the crankshaft 14, has a rotational speed ratio twice the rotational speed of the crankshaft 14, and auxiliary balance weights at both ends thereof. The moment of inertia of (30a, 30b) satisfies the following expression (9), and the phase value of the auxiliary balance weight 30a on the front side of the engine has a phase difference of 5π / 6 with the first crank pin 32a. The phase value of the auxiliary balance weight 30b on the rear side of the engine has a phase difference of pi with the phase value of the auxiliary balance weight 30a on the front side of the engine.

Equation 9 Moment of Inertia (I ') = (0.108 / λ) x reciprocating mass ( ) X crank throw (R) x distance from the center of the first cylinder bore to the center of the third cylinder bore (L) / distance between the auxiliary balance weights (H)-where λ = crank throw (R) / of the connecting rod Length (l).

As described above, when the moment of inertia and phase of the main balance weights 16a to 16f and the three balance shafts 18, 20, and 22 are formed, Equation 1 can be zero. It is possible to remove both the primary component and the secondary component of the inertia superior force.

The unbalanced inertia-running force reduction structure of the three-cylinder engine of the present invention made as described above has an inertia moment and a phase value formed by six main balance weights formed on the crankshaft and three balance shafts each equipped with two auxiliary balance weights. It is possible to offset both the first and second components of the unbalanced inertia and inertia by the rotational mass and the reciprocating mass of the three-cylinder engine, thereby achieving a complete mechanical balance of the crankshaft and the piston mechanism.

As a result, the vibration of the crankshaft can be further reduced, and the noise and vibration characteristics of the engine can be further improved.

Claims (5)

In a three-cylinder engine with three cylinder chambers, Six main balance weights installed at equal intervals of 120 ° on each crank web of the crankshaft having six crank webs; First and second balance shafts each having two auxiliary balance weights mounted at both ends thereof, the center of the shaft being opposed to both sides with respect to the center of the crankshaft so as to be interlocked with the rotational movement of the crankshaft; A third balance shaft having two auxiliary balance weights mounted at both ends thereof, the third balance shaft being operatively installed on the second balance shaft; Including, The unbalanced inertial force reducing structure of the three-cylinder engine, characterized in that the main balance weight and the first, second, third balance shaft to offset the unbalanced inertia. In claim 1, Each of the main balance weights is such that the Inertia moment value satisfies the following equation, and the phase value of each main balance weight pair has a phase difference of crank pin and π between them. Structure of unbalanced inertia rain reduction, Inertia moment (I () = 0.5 × rotational mass (M) × crank throw (R) + 0.25 × reciprocating mass ( Crank throw (R) where crank throw is the distance from the center of the crankshaft to the center of the crank pin. In claim 1, The first balance shaft rotates in the opposite direction to the rotational direction of the crankshaft, has the same speed ratio as the rotational speed of the crankshaft, and makes the moment of inertia of the auxiliary balance weights at both ends satisfy the following equation. The phase value of the auxiliary balance weight has a phase difference of 7π / 6 with the first crank pin, and the phase value of the auxiliary balance weight at the rear of the engine has a phase difference of π with the phase value of the auxiliary balance weight at the front of the engine. Unbalanced inertia power reduction structure of a three-cylinder engine Moment of inertia (I₂) = 0.433 x reciprocating mass ( ) Crank throw (R) x distance from center of first cylinder bore to center of third cylinder bore (L) / distance between auxiliary balance weights (H). In claim 1, The second balance shaft rotates in the opposite direction to the rotational direction of the crankshaft, has a rotational speed ratio twice the rotational speed of the crankshaft, and the moment of inertia of the auxiliary balance weights at both ends thereof satisfies the following equation, The phase value of the auxiliary balance weight on the front side of the engine has a phase difference of 5π / 6 with the first crank pin, and the phase value of the auxiliary balance weight on the rear side of the engine has a phase difference of π with the phase value of the auxiliary balance weight on the engine front side. Unbalanced inertia power reduction structure of a three-cylinder engine, characterized in that Moment of inertia (I₃) = (0.108 / λ) x reciprocating mass ( ) Crank throw (R) x Distance from the center of the first cylinder bore to the center of the third cylinder bore (L) / Distance between auxiliary balance weights (H)-where λ = crank throw (R) / connecting rod Length (l). In claim 1, The third balance shaft rotates in the same direction as the rotational direction of the crankshaft, has a rotational speed ratio twice the rotational speed of the crankshaft, and the moment of inertia of the auxiliary balance weights at both ends thereof satisfies the following equation. The phase value of the auxiliary balance weight on the front side of the engine has a phase difference of 5π / 6 with the first crank pin, and the phase value of the auxiliary balance weight on the rear side of the engine is the phase difference between the phase value of the auxiliary balance weight on the front side of the engine and π. Unbalanced inertia power reduction structure of a three-cylinder engine, characterized in that Moment of inertia (I₄) = (0.108 / λ) x reciprocating mass ( ) X crank throw (R) x distance from the center of the first cylinder bore to the center of the third cylinder bore (L) / distance between auxiliary balance weights (H)-where λ = crank throw (R) / of the connecting rod Length (l).