JPH07688Y2 - piston - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to, for example, a piston of a diesel engine, and in particular, a piston having a high heat load is provided with a top ring without being restricted by various dimensions. The present invention relates to a piston capable of efficiently cooling an annular groove and the like.

[Conventional technology]

The conventional piston made of aluminum alloy
The one described in Japanese Patent Publication No. 54-85209 and whose outline is shown in FIG. 3 is for forming a cooling passage c into which a cooling oil is introduced in a ring tray b cast into a piston a. The cooling passage c is formed in an inverted L-shape having a column portion e standing on the back surface of the ring groove d and a foot portion f extending above the ring groove d. b is mainly composed of two parts, a first part g on which the foot part f is formed and a second part h which is joined to the back surface thereof and mainly forms the pillar part e. is there.

[Problems to be Solved by the Invention] In the structure shown in FIG. 3, the ring tray is simply divided into two parts, but the present invention is further advanced. It is an issue to be solved to increase the design and manufacturing advantages by using the members.

[Means for Solving the Problems]

In this invention, a ring tray having an annular groove for mounting a top ring on an outer peripheral surface thereof is cast integrally with a piston, and cooling oil is introduced into the inside of the ring tray. In the piston in which is formed, two members of the same shape in which an annular semicircular cross-section groove that is a half part of the annular cavity is formed are vertically stacked so that the respective grooves are combined to form an annular cavity. The present invention proposes a piston characterized in that the annular groove is processed into a ring tray after being integrally cast with the piston.

[Action]

Each of the two ring members of the same shape, in which an annular semi-circular groove that forms a half of the annular cavity is formed, each ring tray is formed integrally with the piston by combining the two grooves of the upper part and the lower part. The top ring is mounted in the annular groove to be processed thereafter, and when the piston is operating, the cooling oil flows in the annular groove of the ring tray to cool the annular groove.

〔Example〕

The invention will be described below with reference to the embodiments shown in FIGS. 1 and 2.

In the piston 10 made of aluminum alloy for a diesel engine of FIG. 1, the ring tray 24 has a structure in which the ring tray 24 is divided into upper and lower halves and is composed of a member 26a and a member 26b. The members 26a and 26b are symmetrical with respect to each other with respect to the dividing surface, and these members 26a and 26b are vertically arranged so that the grooves 28a and 28b having an annular cross section and having the same shape are formed on those surfaces. By overlapping them, an annular cavity 28 having a circular cross section is formed.

This annular cavity 28 is formed in the ring tray 24 near the inner peripheral surface of the ring tray 24, and the annular groove 30 is formed on the outer peripheral surface of the ring tray 24 to form a top ring (not shown). ) Is mounted, but when the ring tray 24 is integrally cast into the piston 10, the annular groove 30 is not yet formed, and the annular groove 30 is processed after casting. is there.

FIG. 2 is a sectional view of a part of the members 26a and 26b before the annular groove 30 is processed. A groove 28a that forms the upper half of the annular cavity 28 is formed in the member 26a, and an annular cavity is formed in the member 26b.
A groove 28b is formed which forms the lower half of 28, and these members 26a, 26b are superposed so that the grooves 28a, 28b are aligned.

Returning to FIG. 1, the piston is integrated with the ring tray 24.
After casting 10, the ring protruding portion of the piston 10 and the annular groove 30 are cut by cutting the portion indicated by the dotted line with respect to the ring tray 24, and the step of the lower opening of the piston 10 is cut. An oil supply hole 32 is formed by a drill from the above portion to the upper side, and the oil supply hole 32 penetrates the lower portion of the member 26b and reaches the annular cavity 28.

The lower end opening of the oil supply hole 32 faces the oil jet (not shown), and while the piston 10 is operating, the jetted oil 22 from the oil jet is introduced into the lower end opening of the oil supply hole 32 for cooling. The oil reaches the annular cavity 28 of the ring tray 24 via the oil supply hole 32. Then, it flows through the annular cavity 28, while directly cooling the wall surface of the combustion chamber recess 16 and the annular groove 30.

[Effect of device]

As described above, according to the present invention, the ring trailer is constructed by stacking two members of the same shape on top of each other, and the annular groove in which the top ring is to be mounted has the ring trailer integrated with the piston. Since it is processed after it has been cast, the accuracy of the position of the ring tray and the position of the annular cavity formed inside is improved, and there are few design restrictions and the manufacturing is simple. As a result, the manufacturing cost can be reduced.

[Brief description of drawings]

1 and 2 relate to an embodiment of the present invention, in which FIG. 1 is a longitudinal sectional view of a piston, and FIG. 2 is a sectional view of a part of two members constituting a ring trailer before processing an annular groove. ,
FIG. 3 is a vertical sectional view of a conventional example. 10 ... Piston, 24 ... Ring tray, 26a ... Member, 26b ... Member, 28 ... Annular cavity, 28a, 28b ... Groove, 30
...... Annular groove

Claims (1)

[Scope of utility model registration request] 1. A ring tray having an annular groove on the outer peripheral surface for mounting a top ring is cast integrally with a piston, and an annular cavity into which cooling oil is introduced is formed inside the ring tray. In the formed piston, two members having the same shape in which an annular semicircular cross-section groove that is a half part of the annular cavity is formed are vertically stacked so that the respective grooves are combined to form an annular cavity. A piston characterized by being formed integrally with a piston and then processing the annular groove to form a ring trayer.