JPH0117629Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a piston for an internal combustion engine, and particularly to a piston that has an appropriate oil flow and a sufficient gas sealing function.

As shown in FIGS. 1 and 2, the outer circumferential edge of the lower surface of the top ring groove 2 of a conventional piston 1 is shaved off over the entire circumference to form a stepped portion 3, and this stepped portion 3 is used as an oil reservoir. There are means to prevent oil from rising.

However, in such a case, the top spring groove 2
The outer periphery of the top ring 4 fitted into the piston 4 becomes steeply inclined downward when the piston 1 is actuated, as shown by the imaginary line in FIG.

Therefore, the sealing function of the top ring 4 with the inner surface of the cylinder is significantly reduced.

In view of the above-mentioned points, the present invention provides a piston in which the top ring is kept as tilted as possible during piston operation so that the sealing function can be fully performed. This is a piston for an internal combustion engine that is provided with a plurality of notches or vertical grooves in the circumferential direction.

Next, embodiments of the present invention will be described with reference to the drawings.

The piston 5 of the present invention shown in FIGS. 3 to 5 has a second
A plurality of (eight in this example) notches 7, 7, .

The notch 7 has an opening 7a in the lower surface 9a of the top ring groove 9, the inner wall 7b is disposed at a required depth in the width direction of the lower surface 9a, and the bottom surface 7c is in the height direction of the second land 6. It is disposed at a position below the required length, and has a remaining portion on the lower surface 9a of the top ring groove 9 inward from the notch 7, and also has a remaining portion on the second land 6 below the notch 7.

Since the piston 5 of the present invention is constructed as described above,
When the piston is in operation, the bottom surface 10a of the top ring 10 fitted in the top ring groove 9 is sufficiently covered by the remaining upper shoulder portion 8 excluding the notches 7, 7, etc. cut out in the upper shoulder portion of the second land 6. It is supported without tilting downward and therefore does not interfere with the sealing function.

The piston 11 whose main part is shown in FIG.
A plurality of vertical grooves 13 having openings 13b are provided at equal intervals in the circumferential direction of the second land 12, and the action and effect of the piston 11 is the same as that of the piston 5.

In this case, the outer periphery of the top ring fitted in the top ring groove is not always tilted downward during piston operation, so the gas sealing function can be fully achieved, the pressure in the second land can be secured, and the top ring can rotate. At the same time, it is possible to ensure an appropriate amount of oil rise, and a sufficient contact area of the piston can be ensured, which is effective in preventing seizure.

[Brief explanation of drawings]

Figure 1 is a perspective view showing the main parts of a conventional piston;
Fig. 2 is an explanatory partially longitudinal explanatory view in which the main parts are enlarged, Fig. 3 is a perspective view showing the main parts of the piston of the present invention, Fig. 4 is an explanatory view in which the main parts are enlarged and partially longitudinally cut, Fifth
The figure is an explanatory diagram showing the arrangement of the notches, and FIG. 6 is a longitudinal sectional explanatory diagram of a main part of another embodiment of the piston of the present invention. 5, 11... main piston, 6, 12... second
Land, 7...Notch, 8...Remaining upper shoulder, 9...
...Top ring groove, 10...Top ring, 13
...Vertical groove, 14...Second ring groove.

Claims (1)

[Scope of utility model registration request] A piston for an internal combustion engine in which a plurality of notches or vertical grooves are provided in the circumferential direction of the second land.