JPH0647647U - Cylinder bore lubrication piston - Google Patents

Abstract

(57) [Abstract] [Purpose] In a reciprocating internal combustion engine, the piston skirt portion 21 and the cylinder bore 1 are even when the piston 2 is moving upward.
It is an object of the present invention to provide means for sufficiently performing lubrication between the oil and oil and not impairing the conventional basic function of oil recovery. [Structure] An oil sump (10) having a space above and below is provided in the middle of an oil return hole (9) of an oil ring groove (8) of a piston (2), and a piston skirt portion (21) is formed from the oil sump (10). Oil hole (1
1) is provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to lubrication between a piston skirt portion and a cylinder bore of a reciprocating internal combustion engine.

[0002]

[Prior art]

 As shown in FIG. 3, a piston 2 of a conventional reciprocating internal combustion engine (reciprocating engine) is connected to a crankshaft (not shown) by a connecting rod 3 and a piston pin 4, and vertically reciprocates in a cylinder bore 1. As shown in the figure, the compression rings 5, 6 and the oil ring 7 are attached to the piston 2, and the oil return groove 9 is provided in the oil ring groove 8 through which the oil scraped by the oil ring 7 is removed. It is discharged to the piston rear surface 12 side and returned to an oil pan (not shown).

[0003]

[Problems to be solved by the device]

 The oil ring 7 has a function of scraping off the oil as described above when the piston 2 descends, but on the contrary, in order to scoop up the oil during the compression and exhaust strokes, the piston skirt 21 The amount of oil between the cylinder bore 1 and the cylinder bore 1 becomes small, leading to poor lubrication of this portion, which may cause abnormal wear, scuffing, seizure, etc. of the piston bore 1.

In view of the above problems, in the present invention, the piston skirt portion 21 and the cylinder bore 1 are sufficiently lubricated even when the piston 1 is raised, and the oil recovery rate is good. It is an object of the present invention to provide a piston having means that does not particularly affect oil consumption.

[0005]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, in the present invention, an oil sump having a space above and below is provided in the oil return hole of the oil ring groove of the piston, and an oil hole communicating from the oil sump to the outer circumference of the piston skirt is provided. Provided is a piston with a cylinder bore lubrication mechanism for forward and backward motion internal combustion engines, which is characterized by being provided.

[0006]

[Action]

 When the piston descends, the oil scraped off by the oil ring enters the oil sump, and excess oil flows out from the oil return hole to the back of the piston. When the piston rises, the oil in the oil sump falls to the lower part of the oil sump due to inertia, flows out to the outer circumference of the piston skirt through the oil hole, flows into the gap between the piston skirt and the cylinder bore, and Is fully lubricated.

[0007]

【Example】

 An embodiment of the present invention will be described with reference to the drawings. 1A is a top view of the piston 2, and FIG. 1B is a sectional view taken along the line AA of FIG. As shown in the drawing, an oil sump 10 is provided in the oil return hole 9 of the piston 2, and the oil sump 10 communicates with the outer circumference of the piston skirt 21, that is, between the piston skirt 21 and the cylinder bore 1. An oil hole 11 communicating with the gap is provided. The number of oil return holes 9 and oil holes 11 at this time is not particularly limited. When the oil sump 10 is provided in the piston 2, the oil sump 10 is formed by the same molding method as a general cooling cavity molding using a salt core.

The operation of the piston 2 will be described with reference to FIG. When the piston descends, as shown in Fig. 2 (a), the oil scraped off by the oil ring 7 enters the oil sump 10, and the overflowed oil flows out to the piston back surface 12 through the oil return hole 9 and the oil pan ( Return to not shown). In the figure, the arrow ⇒ indicates the direction of movement of the piston 2, and the arrow → indicates the direction of oil flow.

When the piston rises, as shown in FIG. 2B, the oil accumulated in the oil sump 10 falls to the bottom of the oil sump 10 due to inertia and passes through the oil hole 11 to the piston skirt portion under the oil ring 7. It flows into the gap between 21 and the cylinder bore 1 and lubricates this part. As a result, the oil film is replenished between the cylinder bore 1 and the piston skirt portion 21, which are lifted up by the oil ring 7 and the oil film is reduced, and the lubrication in this part is sufficiently performed.

[0010]

[Effect of device]

 The following effects can be obtained by implementing the present invention. (1) As the oil is sufficiently supplied between the piston skirt part where the oil film is reduced and the cylinder bore when the piston rises, abnormal wear, scuffing, seizure, etc. occur in the piston and cylinder bore. To be prevented. (2) When the piston descends, the scraped oil can be returned to the back of the piston through the oil return hole of the piston, as in the conventional case, so the above basic operation of oil recovery is not impaired. ) Effect can be obtained. (3) The device is simple and cost effective.

[Brief description of drawings]

1 shows a configuration of an embodiment of the present invention, FIG. 1 (a) is a top view of a piston, and FIG. 1 (b) is a sectional view taken along the line AA of FIG. 1 (a).

FIG. 2 shows the operation of the embodiment of the present invention, FIG. 2 (a) is the operation when the piston is descending, and FIG. 2 (b) is the operation when the piston is ascending. Is.

FIG. 3 is a vertical cross-sectional view of a piston in the related art.

[Explanation of symbols]

 1 ... Cylinder bore 2 ... Piston 5, 6 ... Compression ring 7 ... Oil ring 8 ... Oil ring groove 9 ... Oil return hole 10 ... Oil sump 11 ... Oil hole 12 ... Piston back surface

Claims (1)

[Scope of utility model registration request] 1. Oil ring groove (8) in the piston (2)
An oil sump (10) having a space above and below is provided in the middle of the oil return hole (9), and an oil hole (11) communicating from the oil sump (10) to the outer circumference of the piston skirt portion (21) is provided. A piston with a cylinder bore lubrication mechanism for reciprocating internal combustion engines.