JPS6032448Y2 - Two-stage variable flywheel mechanism - Google Patents

Description

[Detailed description of the invention] The present invention relates to a flywheel connected to an internal combustion engine such as a gasoline engine, and more specifically, the inertial mass of the flywheel is reduced depending on the low speed and high speed characteristics and/or load characteristics of the engine. The present invention relates to a two-stage variable flywheel mechanism for a vehicle internal combustion engine, which improves rotational stability during idling and acceleration response during transient times by switching between stages.

A conventional flywheel always has the same inertial mass regardless of whether it is low or high speed.

For this reason, a relatively large inertial mass is attached because it is necessary to suppress rotational fluctuations when the engine is idling and at low speeds.

However, when a flywheel with such a large inertial mass is installed, acceleration performance deteriorates, and therefore, when starting, accelerating and decelerating frequently, such as when driving indoors, the excess inertial mass accelerates and decelerates, reducing the fuel consumption. This is a factor in increasing consumption.

Furthermore, as mentioned above, due to the large inertial mass of the flywheel, it is necessary to increase the strength of the shaft of the output transmission system, that is, the crankshaft of the engine, and in response to this need, increasing the diameter of the crankshaft increases friction loss. Therefore, fuel consumption increases.

On the other hand, as a result of recent exhaust gas countermeasures, the combustion fluctuations of internal combustion engines installed in vehicles are large at low speeds, and the inertial mass of the flywheel is reduced at low speeds in order to avoid impairing vehicle drivability. It is difficult to do so.

In addition, low-speed engines are increasingly being used due to the need to save resources, and it is difficult to reduce the inertial mass of the flywheel from this point of view as well.

In view of the above-mentioned background, the present invention increases the inertial mass of the flywheel at low speeds to reduce rotational fluctuations, while at high speeds the inertial mass of the flywheel decreases to hasten the engine rotation response and improve acceleration. It is an object of the present invention to provide a two-stage variable flywheel mechanism in which the resonance point due to the torsion of the crankshaft that occurs at high speeds can be shifted out of the normal rotation range by reducing the inertial mass of the flywheel. purpose.

In other words, the present invention uses a variable flywheel as a flywheel.
A two-stage variable flywheel for a vehicle internal combustion engine, which is rotatably supported on a flywheel body, and is provided with hydraulic biasing means for locking the variable flywheel to the flywheel body when the engine is running at low speeds and releasing it when the engine is running at high speeds. It is a wheel mechanism.

An embodiment of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, a flywheel body 2 is integrally attached to the rear end of a crankshaft 1 of an engine by a suitable method such as screwing or welding.

The crankshaft 1 is located around the flywheel body 2.
An annular groove is bored coaxially with the shaft, and several thrust ball bearings 21 are mounted on the shaft so that the shaft can slide along a fixed annular guide 51.

A disc-shaped variable flywheel 3 is supported on the crankshaft 1 via a thrust ball bearing 4, and the variable flywheel 3 is rotatable with respect to the flywheel body 2 attached to the crankshaft 1, and the flywheel The wheel body 2 can be advanced to a limited extent.

A clutch plate 32 made of a resin having a large friction coefficient and wear resistance is attached or screwed to the surface of the variable flywheel 3 facing the flywheel body 2.

Note that a clutch plate 32 may be attached to the flywheel body 2 instead of the variable flywheel 3.

An annular groove is bored in the periphery of the variable flywheel 3, and several thrust ball bearings 31 are attached to the variable flywheel 3 so that the variable flywheel 3 can slide along an annular variable flywheel guide 54.

Appropriate locations of the variable flywheel guide 54 are connected to the tip of the piston rod 52 of the hydraulic urging means 5.

The hydraulic urging means 5 includes a cylinder chamber 57 formed in the clutch housing 15, a piston rod 52 that is slidably fitted in the cylinder chamber 57 in a sealed manner, and the piston rod 5.
2 toward the flywheel body 2.

The bellows 55 is a stopper that limits the forward movement of the piston rod 52.

The cylinder chamber 57 of the hydraulic urging means 5 communicates with the hydraulic pump 7 and an oil pan (not shown) via an oil passage 56 and an electromagnetically actuated three-way switching valve 6.

The three-way switching valve 6 is operated by a switching computer 8 which issues an operation signal based on an engine speed signal a and an intake pipe negative pressure signal corresponding to the engine load.

Until the engine speed and/or engine load reaches a preset value, the three-way switching valve 6 communicates the oil passage 56 with the oil pan in response to a signal from the switching computer 8, and no hydraulic pressure is applied to the piston rod 52, so the compression coil The biasing force of the spring 53 presses the variable flywheel 3 together with the piston rod 52 against the flywheel body 2.

Therefore, the flywheel body 2 and the variable flywheel 3 rotate together with the crankshaft 1 around the fixed guide 51 and the variable wheel guide 54.

That is, in this case, as shown in the left half of the solid line B in FIG. 2, the inertial mass of the flywheel is sufficiently large to absorb rotational fluctuations during idling or low rotation.

Next, when the engine speed and/or engine load exceeds a preset value, the switching computer 8 operates the three-way switching valve 6, and the pressurized oil pumped from the hydraulic pump 7 passes through the oil passage 56 to the cylinder chamber. 57, the variable flywheel 3 is separated from the flywheel body 2 by retracting the piston rod 52, and the variable flywheel 3 substantially stops due to the action of the thrust bearing 4 even if the crankshaft 1 rotates.

Therefore, in this case, the inertia t of the flywheel becomes small as shown in the right half of the solid line B in FIG. 2, and the response during transients can therefore be improved.

Furthermore, the broken line C in Fig. 2 shows the characteristics of a conventional flywheel having a constant inertial mass, and by comparing this with the above-mentioned solid line B, it is clear that the present invention is superior (the effect is shown in the shaded area). Will.

Note that the dashed line A indicates ideal flywheel characteristics.

In the embodiment described above, pressurized oil from the hydraulic pump 7 of the engine is supplied during high speed rotation to separate the variable flywheel 3 from the flywheel body 2 against the spring force, but on the contrary, the biasing spring 53 is installed in the cylinder chamber 57 to supply pressurized oil to the opposite side of the variable flywheel 3 during low speed rotation.
may be engaged with the flywheel 2.

However, the former method, which uses pressurized oil during high-speed rotation when the engine output is large, is more preferable.

With this invention, it is possible to change the inertial mass of the flywheel depending on low speed, high speed, and/or the magnitude of the engine load, improving rotational stability at idle and improving the acceleration response during engine transients. A two-stage variable flywheel suitable as a flywheel for an internal combustion engine is obtained.

In addition, the present invention provides a hydraulic biasing means for engaging and disengaging the variable flywheel from the flywheel body, in which oil in the hydraulic supply section is blown away and leaked due to the action of centrifugal force generated when the internal combustion engine is fixed to the hydraulic supply section. Therefore, it is possible to always operate the hydraulic pressure means in a stable and accurate state.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional front view of a two-stage variable flywheel mechanism according to the present invention, and FIG. 2 is a diagram showing the relationship between engine speed and inertial mass. 1...Crankshaft, 2...Flywheel body, 3...Variable flywheel,
4... Thrust ball bearing, 5... Single fluid biasing means.

Claims (1)

[Scope of utility model registration request] An internal combustion engine for a vehicle, comprising: a variable flywheel rotatably supported relative to the flywheel body; and hydraulically biasing means for locking the variable flywheel to the flywheel body when the engine is running at low speeds and releasing it when the engine is running at high speeds. In the staged variable flywheel mechanism, the variable flywheel is rotatable along a variable flywheel guide arranged in an annular manner, and the hydraulic urging means includes a hydraulic pressure supply member provided at a fixed portion of the internal combustion engine and the hydraulic pressure supply. A two-stage variable flywheel for a vehicle internal combustion engine, comprising a piston rod that can be reciprocated by hydraulic pressure from a member, the tip of the piston rod being connected to the variable flywheel guide. mechanism.