JPH0319417B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a balancer mechanism in a reciprocating engine.

Generally, in a reciprocating engine that converts the reciprocating motion of a piston into rotational motion using a crankshaft, the piston,
Large vibrations occur due to inertial force generated by the movement of reciprocating parts such as the connecting rod and crankshaft.

In order to balance this inertial force, a balancer that moves in the opposite direction to the movement of the reciprocating section was provided on the balance shaft to balance out the inertial force.

The present invention uses an elliptical gear to drive the balancer, thereby intentionally changing the angular velocity and angular acceleration of the balancer shaft to which the balancer is fixed relative to the rotation angle of the crankshaft. This balances the high-order components of inertial force that could not be achieved with other systems, resulting in a reciprocating engine with extremely low vibration.

(b) Prior Art As a balancer mechanism in a conventional reciprocating engine, an ordinary circular gear was used between the crankshaft and the balancer shaft in the drive system of the balancer shaft to which the balancer was attached.

Therefore, as the balancer rotated in the same way as the crankshaft rotated, only the primary inertial force of the piston/crank rotation mechanism could be balanced, and the remaining higher-order components caused vibrations. That's what I was doing.

Furthermore, as a conventional similar technique, there is a known technique in which an elliptical gear or an eccentric gear is used in the balancer shaft drive system between the crankshaft and the balancer shaft to eliminate rotational fluctuations in the piston/crank rotation mechanism. It was.

However, the purpose of this similar technology is to eliminate rotational fluctuations in the piston/crank rotation mechanism, and for this purpose, a balancer is provided as a mechanism, and the balancer shaft rotates at a constant angular velocity.
They used elliptical gears and eccentric gears to rotate at low speeds. Therefore, the elliptical gears and eccentric gears were arranged in mesh to change the variable speed rotation of the crankshaft into constant speed rotation of the balancer shaft.

(C) Problems to be Solved by the Invention On the other hand, in the case of the present invention, the angular velocity and angular acceleration of the balancer shaft are further changed with respect to the angular position of the crankshaft, the rotational speed is increased or decreased, and the inertia of the balancer is By having a high-order component, the inertial force of the piston/crank mechanism is balanced against the high-order component.

In other words, by arranging the meshing of the elliptical gears so that the angular velocity and angular acceleration are greatest at the crank angle (top dead center) where the inertia of the piston/crank mechanism is greatest, the rotational fluctuations of the balancer shaft can be greatly reduced. This generates a high-order component of the balancer's inertial force that balances the high-order component of the inertial force of the piston/crank mechanism.

(d) Means for solving the problems The problems to be solved by the present invention are as described above.
Next, we will explain the means to solve the problem.

Converting the reciprocating motion of the piston into rotational force of the crankshaft, rotating the balancer shaft by the rotation of the crankshaft, and rotating the balancer on the balancer shaft,
In a reciprocating engine that balances the inertia of a piston-crank mechanism, the balancer shaft is driven via an elliptical gear train, with the rotation center of the elliptical gear 4 on the crankshaft side being O, and the rotation center of the elliptical gear 4 on the crankshaft side being O, and the balancer shaft being driven on the side of the idle gear shaft. The rotation center of elliptical gear 5 is O', both elliptical gears 4,
If the engagement point of 5 is O'', then O-O'' is maximum and O'-O'' is minimum at the crank angle (TDC) where the inertia of the piston-crank mechanism is greatest. This is what was placed.

(E) Embodiments The problems to be solved by the present invention and the means for solving them are as described above.Next, the structure of an embodiment shown in the attached drawings will be explained.

FIG. 1 is an overall schematic diagram of a reciprocating engine showing an embodiment of the present invention, FIG. 2 is a side view thereof, FIG. 3 is a drawing showing the meshing state of elliptical gears 4 and 5, and FIG.
Figure・Figure 5・Figure 6・Figure 7・Figure 8・Figure 9・
Figures 10 and 11 are continuous drawings of the crankshaft side elliptical gear 4 of the elliptical gears rotated by about 45 degrees, and Figure 12 shows the inertia force a without a balancer device, and the inertia force a with a conventional balancer device. 13 shows the graph of the residual inertia force after balancing by the balancer of the present invention and the ratio λ of the rod length to the crank radius,
Graph showing the range for optimizing the balance of inertia force in relation to the eccentricity ε of the elliptical gear, No. 14
FIG. 15 is a plan view and a side sectional view of an elliptical gear in which a gap is provided in the major axis direction and a weight is provided in the minor axis direction in order to maintain static balance of the elliptical gear itself.

In FIGS. 1 and 2, a piston 1 reciprocates inside a cylinder of an internal combustion engine or the like. The piston 1 is connected to the connecting rod 2 via a piston pin 14. The connecting rod 2 is pivotally connected to the crankshaft 3 via a bearing.

A flywheel 13 is fixed to one end of the crankshaft 3 to eliminate rotational fluctuations of the crankshaft 3 and to provide inertial rotational force. Further, the other end of the crankshaft 3 is provided with an elliptical gear 4, which is an important part of the present invention. The elliptical gear 4 is always in mesh with the elliptical gear 5 of the idle gear shaft 15.
The idle gear shaft 15 is rotated variably by a combination of elliptical gears 4 and 5, and the idle gear 6 meshes with the balancer gear 7 on the balancer shaft 12.

Further, the balancer gear 7 is directly meshed with a balancer gear 8 on another balancer shaft 11. Therefore, balancer gears 7 and 8 rotate in opposite directions. Also, the crankshaft and balancer shaft rotate once in the same amount of time. A balancer 9 is fixed to the balancer gear 7, and a balancer 10 is fixed to the balancer gear 8. The balancers 9 and 10 are arranged at exactly opposite positions to the piston 1.

Further, as shown in FIG. 1, if the rotation center of the crankshaft side elliptical gear 4 is O, the rotation center of the idle gear shaft side elliptical gear 5 is O', and the meshing point of both elliptical gears 4 and 5 is O'', O- at top dead center TDC, where the inertia of the piston/crank mechanism is greatest
They are arranged so that O'' is the maximum and O'-O'' is the minimum. In other words, the angular velocity of the balancer shafts 11 and 12 is at its maximum at the TDC position of the piston. The axis of the elliptical gear is placed at the focal point of the ellipse.

FIG. 3 is an enlarged view of the elliptical gears 4 and 5, showing a state in which the piston 1 is at TDC.

Figure 4 shows two elliptical gears 4 and 5 in Figure 3.
This is a drawing in which the meshing state of the two is arranged on a vertical line.

From the TDC state in Figure 4, the crankshaft 3 is approximately
When rotated by 45 degrees, the idle gear shaft 15 connected to the balancer shafts 11 and 12 rotates by about 45 degrees or more. Then gradually rotate the crankshaft 3 at about 45°.
The rotation angle of the idle gear shaft 15 becomes smaller with respect to the rotation of the crankshaft 3, and in the vicinity of the piston 1 reaching the bottom dead center in FIG. ° or less. or,
From there, the rotation of the idle gear shaft gradually increases with respect to the rotation of the crankshaft, and the state returns to the top dead center state of the piston in FIG. 4.

In the stages shown in FIGS. 11 to 4, the idle gear shaft rotates by more than 45 degrees while the crankshaft rotates by about 45 degrees.

In FIG. 12, the inertia force of the piston-crank mechanism without a balancer is indicated by a. Also shown is the inertial force b remaining after balancing the inertial force a using a conventional balancer device using a circular gear.

However, in the conventional balancer device, inertia force b still remains.

Furthermore, as in the present invention, when the inertial force is canceled using a balancer device that rotates the idle gear shaft using an elliptical gear, changes in the angular velocity and angular acceleration of the balancer occur, resulting in a higher-order component of the inertial force. This balances out the higher order components of inertia of the piston/crank mechanism.

As a result, when the balancer device of the present invention is provided, the residual inertial force becomes as shown in c in FIG. 12, and the inertial force of the piston/crank mechanism almost disappears, and the vibration based on the inertial force becomes close to zero. That is, the inertial force can be reduced by about 96% compared to the case without a balancer, and about 87% compared to the conventional circular gear vibration balancer device. This reduction in inertial force results in the effect of reducing vibration.

FIG. 13 shows the optimum range of rod length and crank radius λ with respect to eccentricity ε.

Eccentricity ε is a value determined by the shape of the ellipse. On the other hand, the rod length/crank radius ratio is λ=
It is the value of l1/l2.

In the present invention, as shown in FIG. 13, the optimum ε for reducing inertial force is determined by the value of λ. In particular, for λ=2 to 4, by setting ε from 0 to 0.18, the inertia of the aircraft can be reduced more than with a normal primary balancer.

In Figures 14 and 15, by using elliptical gears 4 and 5 in the vibration system of the balancer,
The eccentric mass will rotate anew, and the inertia generated by this may cause new vibrations, so even though it is eccentric with the elliptical gears 4 and 5, the center of gravity should be kept static so that it is not eccentric. Balanced oval gears 4, 5 are shown. In particular, gaps 5b and 5c are provided in the thick part of the elliptical gear to reduce the weight in the major axis direction. Also, this void 5
The spokes 5d are left so that the strength of the elliptical gear 5 is not weakened by b and 5c. In addition, in the minor axis direction, since static balance cannot be maintained simply by providing a gap in the major axis direction, protrusions 5a, 5a are provided on both sides to increase the weight. 5e is a hole into which the shaft is inserted. The protrusions may be gradually wedge-shaped or stepped. Also, a weight may be attached instead of the protrusion.

(F) Effect of the Invention The present invention is constructed as described above, and the crankshaft rotates as the piston 1 reciprocates between the dead center and the bottom dead center. were rotating at the same angular velocity as the crankshaft rotated.

Therefore, among the inertial forces of the piston-crank mechanism,
The primary components were able to balance. Moreover, other high-order components could not be resolved if the crankshaft and balancer shaft were rotating at the same time.

In the present invention, since the balancers 8 and 9 rotate at a high angular velocity near the top dead center where the inertial force of the piston/crank mechanism is greatest, the balancers are used to reduce the inertial force of higher order components and the higher order components of the piston/crank mechanism. The inertial forces of the components were balanced.
The angular velocity is reduced near the bottom dead center where only a smaller inertial force is generated.

(G) Effects of the Invention Since the present invention is configured as described above, it has the following effects.

First, the angular velocity and angular acceleration of the balancer axis are
It can be changed with respect to the crank rotation angle, and even high-order components can be balanced against the inertial force generated in the reciprocating part.

Second, at the crank angle (top dead center) where the inertia of the piston-crank mechanism is greatest,
By arranging the meshing of the elliptical gears so that the angular velocity and angular acceleration are maximized, the rotation fluctuation of the balancer shaft is increased and the high-order inertial force of the balancer is balanced against the high-order component of the inertial force of the piston/crank mechanism. It was possible to generate the components.

[Brief explanation of the drawing]

FIG. 1 is an overall schematic diagram of a reciprocating engine showing one embodiment of the present invention, FIG. 2 is a side view thereof, FIG. 3 is a drawing showing the meshing state of elliptical gears 4 and 5, and FIG.
Figure・Figure 5・Figure 6・Figure 7・Figure 8・Figure 9・
Figures 10 and 11 are continuous drawings of the crankshaft side elliptical gear 4 of the elliptical gears rotated by about 45 degrees, and Figure 12 shows the inertia force a without a balancer device, and the inertia force a with a conventional balancer device. 13 is a graph of the residual inertia force b after balancing when the balancer of the present invention is used, and the graph of the residual inertia force after being balanced by the balancer of the present invention. FIG. Drawings showing the optimization range, Fig. 14 is a plan view of the elliptical gear itself with air gaps and weights provided for static balance, and Fig. 15 is the P of Fig. 14.
1, P2, and P3 line sectional view. 1...Piston, 2...Connecting rod, 3...Crankshaft, 4...Crankshaft side oval gear, 5...Idle gear shaft side oval gear, 9,1
0... Balancer, ε... Eccentricity, λ... Rod/
crank radius.

Claims (1)

[Claims] 1. A reciprocating engine that converts the reciprocating motion of a piston into rotational force of a crankshaft, rotates a balancer shaft by the rotation of the crankshaft, rotates a balancer on the balancer shaft, and balances the inertia of the piston-crank mechanism. In this case, the balancer shaft is driven through an elliptical gear train, in which the rotation center of the crankshaft side elliptical gear 4 is O, the rotation center of the idle gear shaft side elliptical gear 5 is O', and both elliptical gears 4 , 5 is O'', the piston-crank mechanism is arranged so that O-O'' is maximum and O'-O'' is minimum at the crank angle where the inertia force of the piston-crank mechanism is greatest. Balancer device for reciprocating engines.