JPH11351333A - Roll vibration reducing device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a roll vibration reducing device for internal combustion engine capable of ensuring a sufficient roll vibration reducing effect under any operating condition. SOLUTION: In a balancer shaft formed of a balancer shaft 10 rotating in the same direction to a crank shaft in order to cancel the unbalanced force of the reciprocating inertial force of an internal combustion engine and having a rotating primary unbalance and a balancer shaft 8 rotating in the reverse direction to the crank shaft and having a rotation primary unbalance, the total of the balancer shaft 8 rotating in the reverse direction and the inertial mass driven by the balancer shaft is set larger than the inertial mass of the balancer shaft 10 rotating in the same direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a mechanism for reducing roll vibration during operation of an internal combustion engine.

[0002]

2. Description of the Related Art As a conventional roll vibration reducing device for an internal combustion engine, there is a technology described in Japanese Patent Publication No. 60-4384. This invention rotates in the same direction with respect to the crankshaft to cancel the unbalance force of the reciprocating inertia force of the internal combustion engine, and rotates in the opposite direction with respect to the shaft having a rotational primary imbalance and the crankshaft. And a balancer shaft constituted by a shaft having a rotational primary imbalance, and the two shafts are arranged with a step in height to reduce roll vibration.

[0003]

However, in such a conventional roll vibration reduction device for an internal combustion engine,
By arranging a shaft having two rotating primary unbalanced mass steps, the moment due to combustion is canceled out,
Although the roll vibration is reduced, the magnitude of the moment due to combustion increases in proportion to the torque generated by the internal combustion engine, but the moment counteracted by the step arrangement is determined by the rotational speed of the internal combustion engine. May not be able to obtain a sufficient effect under all operating conditions. The present invention has been made in view of such conventional problems, and has as its object to provide a roll vibration reduction device for an internal combustion engine that can ensure a sufficient roll vibration reduction effect under all operating conditions. And

[0004]

In order to achieve the above object, the present invention provides a balancer shaft constituted by two shafts rotating in the same direction and opposite directions with respect to a crankshaft and having a rotating primary unbalanced mass. Wherein the sum of the shaft rotating in the opposite direction and the inertial mass driven by the shaft is larger than the inertial mass of the shaft rotating in the same direction. For this purpose, the auxiliary machine is driven in the opposite direction to the crankshaft by the shaft rotating in the opposite direction. Further, the auxiliary machine driven by the shaft rotating in the opposite direction includes a generator having a large inertial mass among the auxiliary machines.

[0005]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 5 is a front view showing a conventional example. First, the configuration will be described. Roller vibration reduction devices for an internal combustion engine according to a conventional example and an embodiment to be described later are both applied to a four-cylinder internal combustion engine. In a conventional example, a cylinder block 1 has a crankshaft (not shown), a balancer shaft 10 having a primary unbalanced mass rotating at twice the rotational speed in the same direction as the crankshaft, and a doubler in a direction opposite to the crankshaft. A balancer shaft 8 having a primary unbalanced mass rotating at a rotational speed is mounted. The balancer shafts 8 and 10 having the two primary unbalanced masses are driven by a crank sprocket 6 attached to a crankshaft and a chain 9. The counter-rotating balancer shaft 8 is driven by a gear from a reversing gear 7 driven by a chain 9. Therefore, the balancer shaft 8 rotates in the reverse direction with respect to the crankshaft. Each sprocket and gears are designed so that the balancer shafts 8 and 10 rotate twice as fast as the crankshaft. The generator 12 has a generator pulley 13 which is driven by the auxiliary drive belt 11 from the crank pulley 5 at the tip of the crankshaft. The generator 12 generally has a rotation speed of about two to three times the crankshaft.
Each pulley is designed and rotates in the same direction as the crankshaft. FIG. 6 is a cross-sectional view of the conventional example of FIG. 5 as viewed from above. The positional relationship among the chain 9, the reversing gear 7, and the accessory drive belt 11 is shown.

Reference numeral 2 denotes a cylinder head, 3 denotes a rocker cover, 4 denotes an oil pan, and 14 denotes a chain case.

FIG. 1 is a sectional view of Embodiment 1 of the present invention as viewed from above. Behind the balancer shaft 8 having the counter-rotating primary unbalanced mass, there is a balance mass 15 which is a rotating primary balanced mass, and rotates integrally with the balancer shaft 8. The method of driving the balancer shafts 8, 10 and the generator 12 is not different from the conventional example.

Next, the operation will be described. Cylinder block 1
Engines that receive the reaction force of torque fluctuation due to combustion,
Roll vibrates. The inertial mass of the crankshaft, flywheel, pulley and other parts attached to the crankshaft is I ₀ , and the inertial mass of the balancer shaft 10 rotating at twice the rotational speed in the same direction as the crankshaft is I
₁ , the inertial mass of the balancer shaft 8 rotating at twice the rotational speed in the opposite direction to the crankshaft is I ₂ , the inertial mass of the generator is I _a , the pulley ratio between the generator and the crankshaft is ρ, the engine and the transmission , The roll acceleration of the power plant is ΔΔΦ, and the engine generated torque is T. At this time,
The equation of motion of the power plant roll vibration is as follows, assuming that the power plant roll angle is sufficiently smaller than the crankshaft rotation angle.

(Equation 1) Becomes In the above equation, the sign of I ₂ , that is, the inertial mass of the counter-rotating balancer shaft 8 is minus, and if this is greater than I ₁ , that is, the inertial mass of the forward-rotating balancer shaft 10, the roll vibration of the engine Can be made smaller.

In this embodiment, the balance mass 15 is rotated together with the balancer shaft 8 which is an unbalanced mass that rotates in the opposite direction, so that I _{2 in the} above equation is obtained.
Is larger than I ₁ . Balancer shaft 8,1
If the unbalanced masses of 0 are not the same, a whirling exciting force is generated, and the function as the balancer shaft may be impaired.

Next, a second embodiment of the present invention will be described. In the first embodiment, the balance mass 15 is added to the balancer shaft 8, so that the inertial mass of the engine rotating unit increases. There is a possibility that a problem such as difficulty in layout for adding the balance mass 15 may occur. The present embodiment and a third embodiment described below solve such a problem.

FIG. 2 is a front view showing this embodiment. In the present embodiment, accessory drive pulley 16 for driving generator 12 is mounted on balancer shaft 8 that rotates in the opposite direction to the crankshaft. As a result, the generator 12 rotates reversely with respect to the crankshaft. A crank damper 17 that suppresses torsional vibration between the crank sprocket 6 and the crankshaft is mounted at the tip of the crankshaft. In the conventional example and the first embodiment, a damper having a similar function is mounted on the crank pulley 5.

A crankshaft and a flywheel,
The inertial mass of a portion attached to the crankshaft such as a pulley is I ₀ , the inertial mass of the balancer shaft 10 rotating at twice the rotation speed in the same direction as the crankshaft is I ₁ ,
The inertial mass of the balancer shaft 8 that rotates at twice the rotational speed in the opposite direction to the crankshaft is I ₂ , the inertial mass of the generator is I _a , the pulley ratio between the generator and the crankshaft is ρ, and the engine and the transmission are Let the inertial mass of the combined power plant be I, the roll acceleration of the power plant be ΔΔΦ, and the engine generated torque be T. With such a configuration, the equation of motion of the roll vibration of the power plant is such that the power plant roll angle is sufficiently smaller than the rotation angle of the crankshaft.

(Equation 2) Becomes The inertia mass of the accessory is also a minus sign, and the roll vibration is further reduced.

FIG. 3 is a cross-sectional view of FIG. 2 as viewed from above, and shows the configuration of the chain 9, the reversing gear 7, and the accessory drive belt 11. The generator 12 rotates at a rotation speed two to three times the rotation speed of the crankshaft, but is driven by the balancer shaft 8 rotating at a rotation speed twice the rotation speed of the crankshaft.
Is about 1 to 1.5, the size of the generator pulley 13 can be reduced, and even with such an arrangement, the layout is difficult.

FIG. 4 is a sectional view of Embodiment 3 of the present invention as viewed from above. The basic configuration, operation and effect are the same as those of the second embodiment. The accessory drive pulley 16 is provided at the rear end of the balancer shaft 8, and the generator 12 is arranged at the center of the engine. With such a configuration, compactness is achieved.

[0015]

As described above, the present invention has an effect that a sufficient roll vibration reduction effect can be ensured under all operating conditions.

[Brief description of the drawings]

FIG. 1 is a sectional view of Embodiment 1 of the present invention as viewed from above.

FIG. 2 is a front view showing a second embodiment.

FIG. 3 is a sectional view of Embodiment 2 in FIG. 2 as viewed from above.

FIG. 4 is a sectional view of the third embodiment as viewed from above.

FIG. 5 is a front view showing a conventional example.

6 is a sectional view of the conventional example of FIG. 5 as viewed from above.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder block 2 Cylinder head 3 Rocker cover 4 Oil pan 5 Crank pulley 6 Crank sprocket 7 Reverse gear 8 Balancer shaft (reverse rotation) 9 Balancer drive chain 10 Balancer shaft (normal rotation) 11 Auxiliary drive belt 12 Generator 13 Generator pulley 14 Chain case 15 Balance mass 16 Auxiliary drive pulley 17 Crank damper

Claims (3)

[Claims] 1. A shaft rotating in the same direction with respect to a crankshaft to cancel an unbalance force of reciprocating inertial force of an internal combustion engine, and a shaft having a rotational primary imbalance, and rotating in a direction opposite to the crankshaft. And a balancer shaft constituted by a shaft having a rotational primary unbalance, wherein the sum of the shaft rotating in the opposite direction and the inertial mass driven by the shaft is the inertial mass of the shaft rotating in the same direction. A roll vibration reduction device for an internal combustion engine, wherein the roll vibration reduction device is larger than the above. 2. The shaft rotating in the opposite direction,
The roll vibration reduction device for an internal combustion engine according to claim 1, wherein the auxiliary machine is driven in a direction opposite to the crankshaft. 3. The apparatus according to claim 2, wherein the auxiliary device driven by the shaft rotating in the opposite direction includes a generator.