JPS6098242A - Balancer of piston crank mechanism - Google Patents

Abstract

PURPOSE:To steeply reduce the unbalanced inertial force by transmitting the rotation of a crank shaft to a balance shaft via eccentric, elliptic gears and rotating the balance shaft at unequal speeds in a serial three-cylinder piston crank mechanism. CONSTITUTION:An eccentric, elliptic gear 33 is fixed concentrically with the crank shaft 7a of a serial three-cylinder piston crank mechanism at the eccentric point 7a on its short axis 33b. An eccentric, elliptic gear 34 engaged with the eccentric, elliptic gear 33 is fixed to a balance shaft 30 at the eccentric point 30a on its long axis 34a. Both gears 33, 34 are also fitted so that their eccentric points 7a, 30a and centers 33c, 34c are aligned in a line when one piston 2 among three cylinders is at the top dead point, and the center 33c is located at the balance shaft 30 side. Counterpoises 27-29 provided corresponding to individual pistons 2, 8, 13 are rotated at unequal speeds by the eccentric, elliptic gears 33, 34.

Description

[Detailed Description of the Invention] The object of the present invention is to provide a simple balance device for eliminating unbalanced inertia couples caused by pistons and other reciprocating masses in internal combustion engines and other in-line three-cylinder piston crank mechanisms. , a balance shaft equipped with a counterweight that balances the inertial couple generated by the piston and other reciprocating masses, and a pair of eccentric elliptical gears fixed to the crankshaft and balance shaft, respectively, to rotate this balance shaft. and a balance device driven by.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be explained in detail using specific examples and drawings.

In the piston arrangement of three cylinders, when one piston of the three cylinders is at the top dead center position, for example, taking piston 2, the piston pin center point 3 and the center line 7 of the crankshaft 7
Based on the case where the center of the crank pin 4 coincides with the line segment 6 connecting the line a, the centers of the crank pins 10 and 15 are:
They are arranged at positions of 120 degrees and 240 degrees, respectively, around the crankshaft center 7a in the rotational direction of the eccentric elliptical gear 33. In this crank arrangement, an inertial couple is generated by the piston and other reciprocating masses, so in order to eliminate these couples, the balance weights 27, 28, and 29 are set as follows. That is, when the piston 2 is at the top dead center, the center of gravity 27a of the balance weight 27 passes through the center 30a of the balance axis and is aligned with the line segment 27b that is in equilibrium with the line segment 6 as shown in the figure. The center of gravity positions 28a and 29a of the balance weights 28 and 29 are set at rotational angular positions of 120 degrees and 240 degrees, respectively, in the rotational direction of the eccentric elliptical gear 34 with respect to the angular position of the center of gravity 27a of the balance weight 27. next,
With respect to the reciprocating mass m of the piston pin and other components, the masses mB1, mB2, and mB3 of each balance weight are set so as to satisfy the following equation.

m×r=mB1×rB1−−−−−−−−−−− (
1) m×r=mB2×rB2−−−−−−−−−−−
- (2) m×r=mB3×rB3------
----- (3) Also, in order to eliminate the inertial couple, set the following formula to be satisfied.

m×r×l1=mB1×rB1×l1a------
(4) m×r×l2=mB2×rB2×l2a----
---(5) m×r×l3=mB3×rB3×l3a-
(6) Next, the phase angle of the eccentric elliptical gear 34 fixed to the balance shaft 30 that meshes with the eccentric elliptical gear 33 fixed to the crankshaft 7 is set as follows.

That is, the arrangement of the eccentric elliptical gears 33, 34 is determined based on the top dead center of any one of the pistons 2, 8, or 13. For example, piston 2
When piston 2 is at the top dead center position,
The short axis 33b of the eccentric elliptical gear 33 and the long axis 34a of the eccentric elliptical gear 34 are arranged in a straight line as shown in the figure.

At this time, the value obtained by dividing the amount of eccentricity by half of the long axis of the eccentric elliptical gears 33 and 34, that is, the eccentricity E and the short axis 33
A value q obtained by dividing b, 34b by the major axes 33a, 34a is set so as to satisfy both of the following equations.

E=0.247×M-0.985 (7) q=0.97
9×(M-3)×0.01 (8) Here, M is the value obtained by dividing the connecting rod length by the crank radius, that is, the connection ratio.

Thus, to explain its operation, when the eccentric elliptical gear 33 fixed to the crankshaft 7 rotates an eccentric elliptical gear having the same outer diameter and the same eccentricity as the eccentric elliptical gear 33,
While the crankshaft 7 rotates at a constant speed, the balance shaft 30 rotates at an inconstant speed. Therefore, the balance axis 30 is primary, secondary
Since it has multi-order rotational periodic components including If the settings are as shown and the balance weights 27, 28, 29 fixed to the balance shaft 30 are set to satisfy equations (1) to (6), the inertia couple remaining in the three-cylinder piston crank mechanism is More than 98% of the data can be erased. Therefore, in the conventional method of employing a circular gear instead of the eccentric elliptical gear according to the present invention, a second-order inertia couple remains, but according to the present invention, more than 98% can be eliminated, and a large width Vibration reduction was achieved.

As described above, according to the present invention, the unbalanced inertia couple can be greatly reduced by simply adopting an eccentric elliptical gear instead of the conventional method of circular gears that are fixed to the crankshaft and balance shaft and mesh with each other. It has the effect of

[Brief explanation of drawings]

Fig. 1 is a mechanical explanatory diagram of the present invention. 2 - Piston 3 - Piston pin 4 - Crank pin 5 - Connecting rod 6 - Piston 2 cylinder center line 7---
- Crankshaft 7a --- Crankshaft center line and eccentric point 8 of eccentric elliptical gear 33 --- Piston 9 --- Piston pin 10 --- Crank pin 11 --- -- Conrod 12 --- Cylinder center line 13 of piston 8 --
--- Piston 14 --- Piston pin 15 --- Crank pin 16 --- Connecting rod 17 --- Cylinder center line 18 of piston 13 ---
--- Crank bearing 19 --- Crank bearing 20 --- Lead line 2 at the center of the cylinder of piston 2
1----- Lead line 22 at the center of the cylinder of the piston 8
-------- Lead line 23 at the center of the cylinder of the piston 13
------ Leader line 24 of the center of gravity position of the balance weight 27---
-- Leader line 25 of the center of gravity position of the balance weight 28 -----
Lead line 26 of the center of gravity position of the balance weight 29------Leader line 27 at an arbitrary position on the crankshaft------ Balance weight 27a------ Center of gravity position 27b of the balance weight 27------ −
Line segment 28 parallel to cylinder center line 6 --- Balance weight 28 a --- Center of gravity position 28 b of balance weight 28 ---
Line segment 29 parallel to cylinder center line 6 --- Balance weight 29 a --- Center of gravity position 29 b of balance weight 29 ---
- Line segment 30 parallel to the cylinder center line 6 ---- Balance shaft 30a ---- Center of the balance shaft and eccentric point 31 of the eccentric elliptical gear 34 ---- Balance shaft bearing 32 ---- Balance shaft bearing 33------ Eccentric elliptical gear 33a fixed to crankshaft 7---Long axis 33b of eccentric elliptical gear 33---
--- Minor axis 33c of the eccentric elliptical gear 33 --- Center point 34 of the eccentric elliptical gear 33 --- Eccentric elliptical gear 34a fixed to the balance shaft --- Long axis 34b of the eccentric elliptical gear 34 --- -- Short shaft 34c of eccentric elliptical gear 34 --
--- Center point m of eccentric elliptical gear --- Reciprocating mass of piston and other parts mB1 --- Mass of balance weight 27 mB2 --- Mass of balance weight 28 mB3 --- Mass of balance weight 29 r------ Crank radius rB1------ Distance from the center of the balance axis to the center of gravity of the balance weight 27 rB2---- Distance from the center of the balance axis to the center of gravity of the balance weight 28 rB3------ Center of the balance axis Distance from to the center of gravity of the counterweight 29

Claims (1)

[Claims] In an in-line three-cylinder piston crank mechanism, a piston,
A balance device equipped with a balance weight that balances the inertial couple generated by other reciprocating masses, and a pair of eccentric elliptical gears fixed to the crankshaft and balance shaft, respectively, provide the balance shaft with nonuniform velocity. The value obtained by dividing the eccentricity by half of the long axis of both eccentric elliptical gears when rotation is applied, that is, the eccentricity E, and the ratio q, which is the ratio of the short axis of the eccentric elliptical gear divided by the long axis, are the connecting rod length. For the value divided by the crank radius, that is, the connection ratio M, E=0.247×
M-0.985, and q=0.979+(M-3)
×0.01, and the eccentric point of the eccentric elliptical gear fixed to the crankshaft is located on the short axis, and the eccentric elliptical gear is fixed to the balance shaft, with the eccentric point aligned with the center point of the crankshaft. Position the eccentric point of the gear on the long axis. Also, when the piston of one of the three cylinders is at top dead center, the short axis of the eccentric elliptical gear fixed to the crankshaft and the long axis of the eccentric elliptical gear fixed to the balance shaft are in a straight line. and a balance device arranged so that the center point of the eccentric elliptical gear fixed to the crankshaft is located on the balance shaft side with respect to the eccentric point.