JPS5999037A - Two-cycle engine designed to drive piston by rolling balls and guide grooves - Google Patents

Abstract

PURPOSE:To reduce the size of an engine and to enable to take out turning force with no use of a conventional crank mechanism, by disposing a cylindrical member fixed to an output shaft in a piston disposed in a cylinder in a freely slidable manner only in the axial direction by the intermediary of rolling balls and cam-like guide grooves. CONSTITUTION:A cylindrical member 10 is fixed, by the intermediary of a fixing member 11, to one end portion of an output shaft 1 located on the side of a cylinder 3, and the output shaft 1 is journalled in a freely rotatable manner at the bottom 12 of the cylinder 3. A plurality of guide grooves 9 (91-96) having an arcuate cross section are formed in the outer surface of the cylindrical member 10 substantially at the circumferentially balanced positions, and rolling balls 8, 8' and so on are put in these grooves 9, i.e., one ball for each groove. These balls 8 are supported in a freely rotatable manner at proper positions on the inner cylindrical portion of a piston 5. Further, an axial groove 7' is formed in the outer cylindrical portion of the piston 5 and a spherical projection 7 fitted in the axial groove 7' is formed at a proper position on the inner surface of the cylinder 3 for preventing rotation of the piston 5. The cylinder 3 is formed with a scavenging passage 19 communicating a compression chamber 13 and a combustion chamber 20 with each other.

Description

[Detailed description of the invention] This invention relates to a two-stroke engine.

Among reciprocating internal combustion engines, 2-cycle engines are simple to install.
It has characteristics such as small torque change and large specific output, but it is also compact and l'! fft is further desired, and higher efficiency is also strongly desired.

The present invention replaces the crank mechanism of a two-cycle engine with a piston driven mrptm+: rolling ball and guide groove, thereby reducing the size and weight of the engine body, and improving the compression performance of scavenging air in a small engine with a crank chamber compression cinere scavenging system. The purpose of this is to improve efficiency, and to provide an on-off valve on the piston instead of the cinnular scavenge to perform efficient scavenging and exhaust, thereby increasing output and improving thermal efficiency.

An actual example of the present invention will first be described with respect to a two-stroke gasoline engine with crank chamber compression and a cinere scavenging system shown in FIG.

The output shaft 1 has a thrust bearing 1 supported by the cylinder bottom 2.
2 sets the axial position so that it can rotate freely about the axis of the cylinder 3, and the mounting is done by part I.
ll and 11' are attached, and a cylinder 10 is provided on the outside thereof. A plurality of guide grooves 9 (9(1) to 9(6)) having an arcuate cross section are provided on the outer peripheral surface of the cylinder 10 at positions substantially in equilibrium with the circumference. One rolling ball 8.8'... is fitted to each guide groove, and each rolling ball 8.8'...
. . . is held at an appropriate position in the inner cylindrical portion of the piston 5 so as to be freely rotatable. The outer cylindrical portion of the piston 5 is set at an appropriate position on the inner surface of the axial cylinder 3 to prevent the piston 5 from rotating. The piston 5 is capable of sliding only in the axial direction along the inner cylindrical surface of the cylinder 3, and is kept airtight by the piston ring 6, and the combustion chamber 20 is formed by the piston top 5', the cylinder 3, and the cylinder head 4, The volume is changed by the movement of the piston 5. A scavenging passage 19 is provided between the compression chamber 13 and the combustion chamber 20, a scavenging hole 14 that is opened and closed by the piston 5 is provided in the inner cylinder surface of the cylinder, and an exhaust hole that is opened and closed by the piston 5 is provided in the cylinder 3. 15 are provided. A mixture of air and fuel is supplied from the intake pipe 17,
It is sucked into the compression chamber 13 via the reed valve 16 according to the pressure difference.

The guide groove 9 provided on the outer circumferential surface of the cylinder 10 has a plurality of identical waveforms at positions that are approximately balanced with respect to the circumference, as shown in the example in FIG. These grooves are a group of grooves that differ in direction, for example, in the form of a sine wave or in the phase of a quadratic curve.

When providing multiple guide grooves, it is possible to avoid crossing the grooves and increase the balance by greatly changing their axial positions, but due to space limitations, it is necessary to avoid crossing each other as shown in the example for miniaturization. arise. By not making the phase difference the same at the intersections of the centers m<tmm> of each guide groove, it is possible to prevent the rolling balls from entering the intersections at the same time. It is possible to change the phase difference of some of the guide grooves within a range where balance can be maintained.

By the rotation of the output @1, each rolling ball 8, 8', etc. receives a force from its respective guide groove, causing the piston 5 to slide and reciprocate within the cylinder along an axial displacement according to the waveform of the guide groove. Conversely, it is also possible to generate rotational movement of the output shaft 1 from the reciprocating movement of the piston 5. The screws 1 to 5 receive the pressure in the combustion chamber, the pressure in the compression chamber, and the force from the rolling balls. The air-fuel mixture is compressed and ignited and combusted by the spark plug 18 near the top dead center, increasing the pressure. As the piston 5 descends, the work is converted into rotational power of the output shaft 1, and the inertial force increases the output @1. The piston 5 is raised again by receiving power from the engine to compress the air-fuel mixture. The volume of the air-fuel mixture supplied from the suction pipe 17 increases as the piston 5 rises, and the volume of the scavenging compression chamber 13 increases.
Since the pressure is reduced, the reed valve 16 opens and the scavenging air flows into the compression chamber. As the piston 5 descends, the air-fuel mixture is compressed and pressurized in the compression chamber, but since the reed valve 16 is a check valve, there is almost no backflow, and when the scavenging hole 14 opens, a pressure difference is created in the combustion chamber in the cylinder. The inflow will depend on the amount. In the cinere scavenging method, when the piston descends and the exhaust hole 15 opens, the gas in the combustion chamber begins to be discharged due to the pressure difference with the exhaust pipe, and when the pressure decreases, the scavenge hole 14 opens and the pressurized scavenge flows into the combustion chamber. gas exchange is carried out. In this case, since the exhaust hole and the scavenging hole are opened and opened respectively at positions symmetrical to the bottom dead center in the piston stroke, the exhaust hole is generally closed after the scavenging hole is closed. Since the scavenging air compression chamber according to the present invention does not require a crankshaft, the volume can be made relatively small, and the scavenging air compression ratio can easily be increased to 1.3 or more.

Because the compression ratio of scavenging air can be increased and it is easy to install a mechanical valve drive device on the compression chamber side of the piston 5, the third
As shown in the figure, a scavenging hole 21 is provided at the top of the piston 5', and a poppet valve 22 for scavenging is arranged so that the timing of opening and closing can be set arbitrarily, rather than symmetrical to the bottom dead center. It is possible to open and close the valves later than the exhaust mainly at the rear.

In this case, there is no need to provide scavenging holes on both sides of the exhaust hole in the cylinder, as in the cinnular air system, and the time between the opening of the exhaust hole and the opening of the scavenging hole is long enough to fully exhaust the air. It is possible to introduce scavenging air,
Since air can be scavenged at asymmetric times centered around bottom dead center, it not only reduces blow-through and achieves high air supply efficiency, but also prevents reverse rotation. By setting the scavenging compression ratio to 1.5 or more, sufficient scavenging can be achieved in a small amount of time and area.

According to the present invention, the reciprocating part is limited to only the piston, and it is not only possible to make it much smaller and lighter than when it has a normal crankshaft (also, the compression ratio of scavenging air can be increased, and the dead center On the other hand, asymmetric scavenging is performed to achieve high air supply efficiency, which allows for high output, improved thermal efficiency, and prevention of reverse rotation.

[Brief explanation of drawings]

Fig. 1 is a sectional view, not showing the structure, of a small two-stroke gasoline engine with a cinere scavenging system according to the present invention, and Fig. 2 shows a cylindrical surface of guide grooves 9(1) to 9(6) provided on the cylindrical surface. The floor plan and FIG. 3 are cross-sectional views showing the structure when the piston is provided with a scavenging poppet valve. 1... Output shaft 3... Cylinder 4... Cylinder head 5... Piston 6... Piston ring 7... Spherical projection 7/-... Groove 8.81
...Rolling ball 9...Guide groove 10...Cylinder 1
2... Thrust bearing 13... Compression chamber 14.
...Scavenging hole 15...Exhaust hole 16...Reed valve
17... Suction pipe 18... Spark plug 19
...Scavenging passage 20...Combustion chamber 21...Scavenging hole 23...Spring 25...Cam Fig. 1

Claims (2)

[Claims] (1) A cylindrical surface that rotates around the axis of the cylinder, in which a guide groove with an arcuate cross section is formed into a smooth interleaved curve that reciprocates in the axial direction with one period per rotation, is located at a position where the circumferential angle is approximately balanced. A piston with an inward surface is provided with a plurality of strips in the cylinder, and a rolling ball is placed in each guide groove, and the ball is rotated freely while being restrained from being placed in the circumferential direction. The central axis of the rotating cylindrical surface is used as an output shaft to penetrate the bottom wall of the cylinder and exit outside.The rotation of this output shaft causes the piston to reciprocate, and the top of the piston, the cylinder head, and the cylinder A two-stroke engine that is driven by screw I/N using rolling balls and guide grooves, with the space formed by the piston and cylinder bottom serving as a compression chamber for scavenging air. (2) Previous%! 2. In the Ikuru machine, Bis!・The poppet valve, which is opened by a cam installed at the shaft end of the rotating cylinder at the top of the cylinder, is opened at the optimal time for scavenging, which is asymmetrical to the movement of the piston, from after exhaust has progressed until after the exhaust hole has closed. , a two-cycle IR cabinet in which a piston is driven by a rolling ball and a guide groove according to claim 1, which employs a scavenging method in which scavenging air is sent from a compression chamber to a combustion chamber via a poppet valve provided at the top of the piston. .