JP2556849Y2 - Piston cooling system - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device for cooling a piston head of an internal combustion engine with cooling oil over the entire circumference of the piston head as uniformly as possible.

[0002]

2. Description of the Related Art In a cast-type piston, a core for forming a cooling cavity in the piston head is held by four leg pieces at the time of casting of the piston. In FIG. 5, a molded piston a has a cooling cavity b at a position where the core is placed, and four vertical through holes c, d, e and f at a position where a leg piece is attached. Conventionally, of these through holes c to f, for example, the through hole c is used as an inlet for the cooling oil, and the cooling oil injection means g is arranged toward the inlet. As shown in FIG. 5, the cooling oil jetted from the jetting means g is supplied to the cooling cavity b, and the cooling oil cools the head of the piston a while using the other through holes d to f as outlets. , So that it is discharged.

[0003]

However, in practice, the flow of the cooling oil in the cooling cavity b is as shown in FIG. 6 and the cooling oil supplied from the through hole c to the cooling cavity b in both directions. Most of the oil is discharged from the next through holes d and f, so that the cooling oil does not sufficiently pass through the section from the through hole d to the through hole f via the through hole e. However, due to poor cooling of the piston head in this part, there is a possibility that seizure may occur, and in particular, the need for thinning to suppress engine vibration and noise due to the vertical movement of the piston in the cylinder. As a result, when the diameter of the outlet of the cooling oil is increased by enlarging the through hole, the tendency of insufficient cooling is further increased, and a countermeasure is required.

[0004]

SUMMARY OF THE INVENTION Here, the present invention provides a cooling oil inlet / outlet for an annular cooling air cavity (2) formed in the thickness of a piston head. In a piston cooling device using four through holes (3, 4, 5, 6) formed by leg pieces holding a component core, these through holes (3,
Two injection means (7, 8) for injecting and supplying cooling oil to the cooling cavity (2), respectively, facing two through holes (3, 4) adjacent to each other. ) Is provided, and the flow of the oil required for cooling is provided on the upper wall surface of the inlet of the cooling cavity (2) to which the cooling oil injected from the one injection means (7) is supplied. A projection (9) for distributing the cooling oil to the cooling water is formed on the upper wall surface of an inlet of a cooling cavity (2) to which cooling oil injected from the other injection means (8) is supplied. A projection (10) is formed for directing the entire amount of oil as a strong flow only in the direction opposite to the direction of the through hole (3), that is, in the direction of the through hole (5). Then, the cooling oil is distributed as uniformly as possible to the entire area of the cooling cavity (2) by the two flows. Made as to Watarura, it proposes a cooling device of the piston.

[0005]

In the cooling device of the present invention having the above structure, the supply of cooling oil into the cooling cavity is performed by two injection means, and the cooling cavity communicates with the through hole forming the oil inlet. Protrusions for distributing or directing the cooling oil are provided on the upper wall surface of the inlet so that the cooling oil can be distributed as evenly as possible over the entire area of the cooling cavity.

[0006]

FIG. 2 is a cross-sectional view taken along the line A--A of FIG. 1, showing an annular cooling cavity 2 formed in the head of a piston 1. FIG.
And four through holes 3, 4, 5, 6 in the vertical direction formed at substantially equiangular intervals around the entire circumference of the cooling cavity 2, respectively holding the core during piston casting and the core. It is formed by the leg pieces.

[0007] Of the through holes 3, 4, 5, 6, two adjacent through holes, ie, the through holes 3 and 4 are used as inlets for cooling oil, and the cooling holes are provided facing the through holes 3 and 4 for cooling. Oil injection means 7 and 8 are arranged close to one side on the entire circumference of the piston, and cooling oil is injected from these injection means 7 and 8 toward the cooling cavity 2 as shown in FIG. 1, for example. It is. At this time, at the entrance of the cooling cavity 2, the cooling oil is distributed and directed.

That is, a mountain-shaped projection 9 as shown in FIG. 3 is formed on the upper wall surface of the inlet of the cooling cavity 2 of the cooling oil injected and supplied from the injection means 7 through the through hole 3. The cooling oil is distributed and distributed in both directions in the cooling cavity 2, while the cooling oil injected and supplied from the injection means 8 through the through hole 4 is provided on the upper wall surface of the inlet of the cooling cavity 2. That is, a mountain-shaped projection 10 is formed in which the entire amount of the cooling oil is directed only in the direction opposite to the through hole 3.

With this arrangement, the flow of the cooling oil is indicated by arrows in FIGS. 2 and 3, and the cooling oil having the through hole 3 as an inlet flows through the cooling cavity 2. The cooling oil is circulated and discharged through the through-holes 4 and 6 as outlets, and the cooling oil through the through-holes 4 becomes a strong flow, and the entire cooling oil becomes strong.
It flows through the inside, passes through the through-hole 5, and is discharged with the through-hole 6 as an outlet.

[0010]

According to the above structure of the present invention, the cooling oil is distributed as uniformly as possible over the entire area of the annular cooling cavity formed in the piston head by the two injection means. This has the effect of effectively cooling the piston head and preventing the occurrence of inconvenience caused by partial cooling insufficiency. The diameter can be reduced, and the weight of the casting piston can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of the head of a piston provided with the cooling device of the present invention.

FIG. 2 is a cross-sectional view showing the cooling device of the present invention,
It is AA sectional drawing of FIG.

FIG. 3 is a perspective view showing a configuration of a projection in a cooling cavity and a flow of cooling oil in the cooling cavity.

FIG. 4 is a sectional view of a head of a piston provided with a conventional cooling device.

5 is a cross-sectional view of a conventional example, and is a cross-sectional view taken along line BB of FIG.

FIG. 6 is a perspective view showing a state of circulation of cooling oil in a cooling cavity in a conventional example.

[Description of Signs] 1 Piston 2 Cooling cavity 3, 4, 5, 6 Through hole 7, 8 Injecting means 9, 10 Projection

Claims (1)

(57) [Scope of request for utility model registration] 1. An inlet / outlet for cooling oil for an annular cooling cavity (2) formed in the thickness of the piston head , formed by legs holding the core for forming the cooling cavity (2) during casting of the piston. 4 holes (3, 4, 5,
6) In the piston cooling device using the cooling cavities, the cooling cavities are respectively opposed to two adjacent through holes (3 , 4) among the through holes (3, 4 , 5, 6).
Two injection means (7, 2) for injecting and supplying cooling oil to (2)
8) is disposed on the upper wall surface of the inlet of the cooling cavity (2) to which the cooling oil injected from the one injection means (7) is supplied.
The cooling cavity the protrusion to distribute in both directions of the flow of cooling oil cooling cavity (2) to form a (9), the cooling oil to be injected from the other injection means (8) is supplied On the upper wall of the entrance of (2) , all of the cooling
The amount of the through-hole (3) opposed by the one injection means (7)
Strong only in a direction opposite direction, i.e. hole (5) to the direction
Forming a projection (10) for turning as a flow ,
Thus, the entire cooling cavity (2) is formed by the two flows.
A cooling device for a piston, wherein the cooling oil is spread as evenly as possible over the region .