JPH02211357A - Piston lubricating device for four-cycle engine - Google Patents

Abstract

PURPOSE:To obviate the need of the burr removing work and achieve cost cut and improve lubricity by forming a plurality of recessed parts on the skirt part on the outer periphery of a piston and drilling an oil reservoir and small holes which penetrate through the inside at the center part of the recessed part according to necessity. CONSTITUTION:A plurality of recessed parts 3 are formed on the lower part skirt part 2 on the outer periphery of a piston 1. The recessed part 3 is formed into an oil storage, and lubricating oil can be stored. If the situation is not sufficient by only foring the recessed part 3, small holes 4 are formed by a stwisting drill, and even if burrs are left, the burrs are formed on the recessed part, and no burr is formed on the side having sliding surface for a cylinder, and the need of burr removing work is obviated. The lubricating oil splashed up from inside is introduced into the small hole 4, and the stay of the lubricating oil in the recesed part 3 is improved further, and sufficient lubrication is permit ted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a piston lubrication device for a four-stroke engine.

[Conventional technology]

A four-cycle engine has lubricating oil sealed in the lower part of the crank chamber, and the rotation of the crankshaft and connecting rod draws up the lubricating oil to lubricate the sliding movement of the cylinder and the piston. The piston has a ring groove on the outer periphery near the piston head, and the combined three rings (top ring and second ring) are fitted to keep the sliding surfaces of the piston and cylinder airtight. An oil ring is fitted into the ring groove and the lubricating oil is scraped off by the oil ring to prevent the lubricating oil from entering the combustion chamber above the piston head. If the oil ring scrapes off too much lubricating oil, an oil film will form on the skirt at the bottom of the outer circumference of the piston, resulting in insufficient lubrication. For this reason, as shown in FIGS. 7 and 8, the skirt portion A of the piston has a plurality of diameters 1 to 1.
Approximately two holes B are drilled through the piston to prevent lubricant oil from being pumped up from the inside of the piston, passing through the holes B and entering the outer skirt portion A, thereby preventing the lT11 from becoming insufficiently clean.

[Problem to be solved by the invention]

In the above-mentioned conventional technology, the hole B is formed by drilling it with a drill, and when drilling, a hole is formed at the end.
There is a problem in that the processing cost is high when chamfering the threads for deburring. Further, since the holes are individually drilled one by one in the radial direction, there is a problem that the cost of the layer increases.

In view of this, the present invention provides a plurality of depressions in the skirt portion of the piston to serve as oil reservoirs, and also eliminates the need for deburring when a small hole leading to the inside is bored in the center of the depression. The object of the present invention is to obtain a piston lubrication device for a four-stroke engine that can reduce costs and have good lubricity.

[Means to solve the problem]

In order to achieve the above object, the piston lubrication device for a four-stroke engine of the present invention includes a plurality of depressions in the outer skirt portion of the piston, and a small hole penetrating inwardly in the center of the depression as necessary. This is because it was established.

[Effect]

The multiple depressions provided in the outer circumference skirt of the piston can serve as oil reservoirs and store lubricating oil.
Preventing the oil film from running out on the skirt part, r! The lack of J slide can be solved. The depressions can be formed at the same time as the piston is cast, which saves processing time. Furthermore, even when a small hole leading to the inside is drilled in the central portion of the recess, since the hole is drilled in the recessed portion, there is no need to perform deburring, and manufacturing is possible at low cost.

(Example) Hereinafter, an example of the present invention will be described with reference to FIGS. 1 to 6.

1 and 2 show an embodiment of the present invention. A plurality of depressions 3 are provided in a skirt part 2 at the lower part of the outer circumference of the piston 1. The recess 3 may be formed at the same time as the piston 1 is cast, and no labor is required for production. The depression 3 becomes an oil reservoir and can store lubricating oil.

3 to 5 show other embodiments of the present invention. As shown in FIGS. 1 and 2, if it is insufficient to provide a plurality of recesses 3 in the skirt portion 2 of the piston 1, a small hole 4 penetrating inwardly may be inserted in the center of the recess 3. to drill. In this case, even if a hole is formed by drilling the small hole 4, it is formed in the recess 3 and does not come out on the sliding surface with the cylinder, so there is no need to remove the hole.

The lubricating oil that has been scooped up from the inside enters the small hole 4, which improves the retention of the lubricating oil in the recess 3 and provides sufficient lubricating oil.
I can play ff1.

FIG. 6 shows a special drill 6 provided with a step 5. If the small hole 4 is drilled with such a drill 6, the depression 3 can be formed at the same time by cutting. When providing the small holes 4, the depressions 3 can also be provided at the same time in this way.

〔Effect of the invention〕

As explained above, since this invention is configured as described above, lubricating oil can be stored in the plurality of depressions, the skirt portion can be sufficiently lubricated, and scuffing and seizure of the piston can be prevented. . If the recess is insufficient, lubricating oil can be replenished by providing a small hole in the center of the recess that penetrates inside. The recesses can be formed at the same time as the piston is cast, and even when small holes are drilled, there is no need for deburring, so manufacturing costs can be reduced. Furthermore, by improving the lubricity of the skirt portion of the piston, mechanical loss can be reduced and performance can be improved.

[Brief explanation of the drawing]

1 and 2 show one embodiment of the present invention, FIG. 1 is a cross-sectional view, FIG. 2 is a perspective view, and FIGS. 3 to 5 show other embodiments of the present invention, Fig. 3 is a longitudinal sectional view, Fig. 4 is a perspective view, Fig. 5 is an enlarged longitudinal sectional view of main parts, Fig. 6 is a side view showing the special drill used in the present invention, and Figs. 7 and 8 are conventional drills. An example is shown, FIG. 7 is a longitudinal sectional view, and FIG. 8 is a perspective view. 1... Piston, 2... Skirt part, 3... Recess, 4... Small hole. l Old Atsushi Notification Ward Map, No. 1? Diagram δ diagram

Claims (1)

[Claims] 1. A piston lubrication device for a four-cycle engine, characterized in that a plurality of depressions are provided in the outer peripheral skirt portion of the piston, and a small hole penetrating inwardly is formed in the center of the depression as necessary.