JPH0625534U - Piston for internal combustion engine - Google Patents

Abstract

(57) [Abstract] [Purpose] For an internal combustion engine that allows oil relief holes to be easily machined and allows the oil scraped by the oil ring to be reliably discharged without being obstructed by the cooling oil flowing down the inner surface of the piston body and flowing down. Provide the piston. [Structure] An oil escape hole 14 is formed along the radial direction of the piston body 1 at the bottom of an oil ring groove 4 formed on the outer periphery of the piston body 1, and an oil outlet portion 14a of the oil escape hole 14 is formed. The protrusions 15 and 17 are formed on the inner surface 1c of the piston body 1, and the protrusions 15 and 17
17, an oil guide surface 15a having a convex shape toward the upstream side of the cooling oil C that is injected to the back surface 1b of the crown portion 1b of the piston body 1 and flows down along the inner surface 1c of the piston body 1,
17a was formed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention relates to a piston for an internal combustion engine.

[0002]

[Prior art]

 Generally, in a piston for an internal combustion engine, an oil escape hole is formed at the bottom of an oil ring groove formed on the outer peripheral portion of the piston body, and the oil ring inserted into the oil ring groove causes the oil ( (Lubricating oil) is scraped off and discharged to the inside of the piston body, but in the case of cooling the piston body by injecting cooling oil (lubricating oil) to the back of the crown of the piston body with an oil jet In some cases, since the cooling oil flows down along the inner surface of the piston body, the oil scraped by the oil ring may be hindered by the cooling oil flowing down and may not be discharged inside the piston body.

Therefore, as a piston for an internal combustion engine capable of avoiding such a situation, there is a piston disclosed in, for example, Japanese Utility Model Publication No. 55-114329. In this piston for an internal combustion engine, the oil relief hole communicates with the lateral hole extending in the radial direction of the piston body and the inner end of the lateral hole, and extends in the axial direction of the piston body toward the crank chamber side. It consists of a vertical hole that opens.

[0004]

[Problems to be solved by the device]

 However, the lateral hole extending in the radial direction of the piston body in the conventional piston for an internal combustion engine can be easily machined from the outer peripheral side of the piston body, but the vertical hole extending in the axial direction of the piston body has a skirt portion. Since it had to be machined from the side, and the processing location was inside the piston body, it was difficult to work. For this reason, there are drawbacks that productivity is deteriorated and cost is increased in combination with machining from two directions.

The present invention has been made to solve the above-mentioned conventional problems, and an oil escape hole can be easily processed, and an oil ring can be used without being obstructed by cooling oil flowing down the inner surface of the piston body. An object of the present invention is to provide a piston for an internal combustion engine that can reliably discharge scraped oil.

[0006]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the piston for an internal combustion engine according to the present invention has an oil escape hole formed in the bottom of an oil ring groove formed in the outer periphery of the piston body along the radial direction of the piston body. A protrusion that forms the oil outlet of this oil escape hole is formed on the inner surface of the piston body, and cooling oil that is injected onto the back surface of the crown of the piston body and flows down along the inner surface of the piston body onto the protrusion Is formed on the upstream side of the oil guide surface.

[0007]

[Action]

 With such a configuration, the cooling oil that flows down along the inner surface of the piston body is guided to the oil guide surface of the protrusion and diverges from the oil outlet of the oil escape hole. Therefore, the oil scraped by the oil ring is discharged from the oil outlet of the oil escape hole to the inner surface of the piston body without being hindered by the cooling oil.

[0008]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a vertical cross-sectional view showing a piston for an internal combustion engine, FIG. 2 is a view taken in the direction of arrow A in FIG. 1, and FIG. 3 is a cross-sectional view taken along line BB in FIG.

In the figure, reference numeral 1 denotes a piston main body. On the outer periphery of the piston main body 1, bottomed annular pressure ring grooves 2 and 3 and an oil ring groove 4 are formed side by side with an interval. The pressure rings 5 and 6 are inserted into the oil ring groove 4, and the oil ring 7 is inserted into the oil ring groove 4.

Such a piston is slidably accommodated in a cylinder 8 of a cylinder block, is connected to a crank shaft (not shown) via a connecting rod 10 mounted on a piston pin 9, and is connected to each ring 5, 6 and 7 are constantly in pressure contact with the inner peripheral wall 8a of the cylinder 8. The piston divides the inside of the cylinder 8 into a combustion chamber 11 and a crank chamber 12. Then, the piston receives combustion pressure on its crown surface 1a, slides in the cylinder 8, and transmits power to the crankshaft via the connecting rod 10.

Reference numeral 13 denotes an oil jet, which is installed on the lower surface of the cylinder block, and injects the cooling oil C toward the crown back surface 1b of the piston body 1 to force the piston body 1 during the engine operation. It can be cooled to.

A plurality of oil escape holes 14 are formed at the bottom of the oil ring groove 4 along the radial direction of the piston body 1, and the inner surface 1 c of the piston body 1 has an oil escape hole 14 for each oil escape hole 14. A protrusion 15 that forms the oil outlet portion 14a is formed.

An oil guide surface 15a is formed on the protrusion 15 and is convex toward the upstream side of the cooling oil C that is injected onto the back surface 1b of the crown portion 1b of the piston body 1 and flows down along the inner surface 1c of the piston body 1. Has been done.

Further, on the inner surface 1c of the piston body 1, a concave groove 16a extending from the position of the protruding portion 15 to the crown back surface 1b side of the piston main body 1 for each protruding portion 15, and the concave groove 16a A substantially Y-shaped oil passage 16 is formed by two concave grooves 16b extending continuously on both sides of the protrusion 15 toward the crank chamber 12 side. Therefore, the protrusion 15 is formed on the inner surface 1c of the piston body 1 by the formation of the oil passage 16.

In the above configuration, when the cooling oil C is injected from the oil jet 13 to the crown back surface 1b of the piston body 1, the cooling oil C flows down from the crown back surface 1b of the piston body 1 along the inner surface 1c. The cooling oil C ₁ having entered the concave groove 16a of the oil passage 16 is guided into the concave groove 16b of the oil passage 16 by the oil guiding surface 15a of the protrusion 15 and escapes from the oil outlet portion 14a of the oil escape hole 14. It flows. The cooling oil C _{2 that} has not entered the oil passage 16 flows along the inner surface 1c of the piston body 1 as it is.

Next, another embodiment of the present invention will be described with reference to FIGS.

FIG. 4 is a view corresponding to FIG. 2, and FIG. 5 is a sectional view taken along the line D-D of FIG. The same parts as those in the previous embodiment are designated by the same reference numerals.

This embodiment is different from the previous embodiment in that the protrusion 17 forming the oil outlet portion 14a of the oil escape hole 14 is formed so as to protrude from the inner surface 1c of the piston body 1.

In the above structure, the cooling oil C injected to the back surface 1b of the crown portion 1 of the piston body 1 flows down along the inner surface 1c of the piston body 1 and flows down to the oil outlet portion 14a of the oil escape hole 14. ₃ is guided by the oil guide surface 17a of the projection 17 and flows away from the oil outlet 14a of the oil escape hole 14.

The shape of the oil guiding surface 15a formed on the protrusion 15 is round, and the shape of the oil guiding surface 17a formed on the protrusion 17 is triangular, but the inner surface 1c of the piston body 1 is Needless to say, the shape of the cooling oil C is not limited as long as it is convex toward the upstream side of the cooling oil C.

[0022]

As described above, according to the present invention, the oil escape hole is formed in the bottom of the oil ring groove formed on the outer peripheral portion of the piston body along the radial direction of the piston body. A protrusion that forms an outlet is formed on the inner surface of the piston body, and the protrusion is projected toward the upstream side of the cooling oil that is injected on the back surface of the crown of the piston body and flows down along the inner surface of the piston body. Since it has an oil guiding surface that is shaped like a circle, the oil relief hole can be easily machined from the outer peripheral side of the piston body, and the protrusions can be integrally formed at the same time when the piston body is cast, so that the productivity of the piston is improved. It is possible to improve and reduce the production cost. In addition, the cooling oil sprayed on the back surface of the crown of the piston body and flowing down along the inner surface of the piston body is guided by the oil guide surface formed on the projection and flows away from the oil outlet of the oil escape hole. The oil scraped by the oil ring can be discharged from the oil outlet of the oil escape hole to the inner surface of the piston body, which allows the oil ring to fully perform its function during engine operation. Lubrication oil consumption can be reduced.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a piston for an internal combustion engine according to an embodiment of the present invention.

FIG. 2 is a view on arrow A in FIG.

3 is a sectional view taken along the line BB of FIG.

FIG. 4 is an enlarged view corresponding to FIG. 2 showing an internal combustion engine piston according to another embodiment of the present invention.

5 is a cross-sectional view taken along the line DD of FIG.

[Explanation of symbols]

1 Piston main body 1b Crown back surface 1c Inner surface 4 Oil ring groove 7 Oil ring 14 Oil escape hole 14a Oil outlet 15 and 17 Projection 15a and 17a Oil guide surface 16 Oil passage C, C ₁ , C ₂ , C ₃ Cooling oil

Claims (1)

[Scope of utility model registration request] 1. An oil escape hole is formed in a bottom portion of an oil ring groove formed in an outer peripheral portion of the piston body along a radial direction of the piston body, and a protrusion portion forming an oil outlet portion of the oil escape hole is provided. An oil guide surface is formed on the inner surface of the piston body, and an oil guide surface that is convex toward the upstream side of the cooling oil that is injected onto the back surface of the crown of the piston body and flows down along the inner surface of the piston body is formed on the protrusion. An internal combustion engine piston.