JPH05332114A - Piston lubricating device by oil nozzle hole of connecting rod small end part - Google Patents

Abstract

PURPOSE:To carry out sufficient lubrication not to cause abnormal abrasion, seizure and others between a piston and a cylinder inwall in an up stroke process of the piston in an engine furnished with a means to inject oil on the inwall of the piston from an oil nozzle hole provided on the small end part of a connecting rod. CONSTITUTION:A ring oil reservoir groove 14 is formed on a shoulder part 121 of a piston skirt part 12, an oil hole communicated from the inwall of a piston 1 through to the oil reservoir groove 14 is drilled and provided on an external wall 16 on the anti-thrust side of the piston 1, and an oil nozzle hole 38 is arranged so that oil injected from the oil nozzle hole 38 flows in an oil hole 17 at the time of an up stroke process of the piston 1 and it is injected toward the inwall 10 of the piston 1 at a position not communicated through to the oil hole 17 at the time of a down stroke process of the piston 1.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD This invention relates to the lubrication and cooling of engine pistons and cylinders.

[0002]

2. Description of the Related Art Conventionally, an engine provided with a means for injecting oil (lubricating oil) into the inside of a piston from a nozzle provided at a small end of a connecting rod (also called connecting rod) of the engine cools the piston with this oil. What is used is to cool and at the same time to be used for lubrication between the piston and the cylinder at the same time as cooling.

FIG. 6 shows a normal oil passage of the conventional engine until oil is supplied to the piston through the connecting rod. In the figure, 1 is a piston, 2 is a piston pin, 3 is a connecting rod, 4 is a crankshaft, 5 is a cylinder block, 6 is a cylinder head, 7 is a combustion chamber,
8 is a compression ring and 9 is an oil ring.

The oil L pumped by an oil pump (not shown) in the engine passes through an oil passage 53 from an oil main hole 52 in the cylinder block 5 to the oil passage 41 in the crankshaft 4 and the large end 3 of the connecting rod.
2 bearing 33, oil passage 3 in connecting rod 3
4. The oil is injected to the inner wall (also referred to as the inner side or the back side) 10 of the piston 1 from the injection port 37 formed in the connecting rod small end 31 through the annular oil passage 35 surrounding the piston pin 2.

FIG. 7 is a partially enlarged view of the piston 1, the piston pin 2, and the connecting rod small end portion 31 taken along the line II of FIG. In the figure, the oil L is injected from the oil passage 34 through the annular oil passage 35 into the inside of the piston 1 through the injection port 37 to cool the piston 1. Further, this oil is the oil port 131 of the oil ring groove 13 into which the oil ring 9 is fitted, or the piston head 11
A slit (not shown) provided in the adjacent portion between the piston skirt portion 12 and the piston skirt portion 12, or the like, or
It flows into the sliding surface between the piston and the cylinder through the lower end portion 122 of the piston skirt portion 12 and the like, and lubricates between them. The oil ring 9 scrapes off the oil so that excess oil does not enter the combustion chamber 7.

4 and 5 schematically show the left and right movement of the piston 1 in the cylinder 50 as the piston 1 moves up and down. FIG. 4 shows a state near the top dead center of the ascending stroke of the piston 1, and FIG. 5 shows a state near the top dead center of the descending stroke of the piston 1. As shown in FIG. 5, during the downward stroke of the engine, particularly during the explosive stroke, the cylinder inner wall 5 of the piston 1
1 is subjected to a large lateral pressure (thrust) F ₁ , and therefore this side of the piston is called the thrust side outer wall 15. On the other hand, during the upward stroke of the piston, the lateral pressure f weaker than this
₁ hangs on the side opposite to the above, and this side is called the anti-thrust side outer wall 16 of the piston.

FIG. 4 (a) is a longitudinal sectional view of the piston 1 and the cylinder 50 when the piston 1 rises to near the top dead center in the upward stroke, that is, in the compression and exhaust strokes.
4B is a sectional view taken along line IV-IV of FIG. As shown in the drawing, when the crankshaft 4 rotates clockwise as shown by the arrow in the drawing, the piston is pushed up by the connecting rod 3 with the force of f, and the corresponding force f ₁ is applied to the piston pin 2, so that the piston 1 is the anti-thrust of the piston. The side outer wall 16 contacts the inner wall surface 51 of the cylinder 50, and at this time, a gap is formed between the thrust side outer wall 15 of the piston and the cylinder inner wall 51 as shown in the drawing.

FIG. 5 shows a state in the vicinity of top dead center when the piston 1 completes the above-described ascending stroke and reaches the top dead center and then moves to the descending stroke, that is, the intake / explosion stroke. At this time, the strong explosive force F as shown in the figure is received during the explosive stroke, and the component force F ₁ is applied to the piston pin 2 and the piston 1
The thrust-side outer wall 15 is pressed against the inner wall surface 51 of the cylinder 50 by this strong force F _1, and a gap is formed between the anti-thrust-side outer wall 16 of the piston and the inner wall 51 of the cylinder 50.

As described above, the piston swings to the left and right with each vertical movement, and the thrust-side outer wall 15 and the anti-thrust-side outer wall 16 of the piston alternately abut the cylinder inner wall surface 51. Since it is large, it causes slap noise and wear.

[0010]

In order to suppress the occurrence of the above-mentioned slap noise and wear, various measures have been conventionally made. In Japanese Utility Model Laid-Open No. 61-65214, an oil hole penetrating the inside and the outside of the piston is bored, and an oil film is formed between the thrust side wall of the piston and the cylinder inner wall surface by the oil injected into this oil hole. It is formed to reduce the slap sound.

According to Japanese Utility Model Laid-Open No. 1-130021, a guide valve made of a temperature sensitive material is provided in the skirt portion of the piston, and this guide valve supplies the injected oil to the thrust side of the piston to reduce the slap noise. There is.
As described above, various measures have been actively taken in the past for measures against problems on the thrust side of the piston, such as measures for reducing slap noise. However, on the other hand, when the anti-thrust side contacts the cylinder inner wall as shown in FIG. However, there are the following problems that differ from those on the thrust side, but no countermeasures have been taken so far.

That is, the oil ring 9 shown in FIG. 7 has a function of scraping off the oil as described above, which works effectively in the downward stroke of the piston 1 as shown in FIG. On the other hand, during the upward stroke of the piston as shown, that is, during the compression and exhaust strokes, the oil is scraped up, so that the oil between the piston skirt portion 12 and the cylinder inner wall 51 is scraped up, resulting in poor lubrication. As shown in the figure, since the side wall 16 on the anti-thrust side of the piston 1 is pressed against the cylinder inner wall 51, pressure sliding is performed in a state of insufficient oil, causing abnormal wear on the piston, the cylinder inner wall, etc. (Scratches), seizure, etc. may occur, and the inner wall surface (bore) of the cylinder may become a mirror surface.

In order to solve the above-mentioned problems, in the present invention, positive and sufficient lubrication is positively performed so that abnormal wear, seizure, etc. do not occur between the piston and the inner wall of the cylinder in the upward stroke of the piston. It is an object to provide an oil supply means that can be used.

[0014]

In order to achieve the above object, the present invention provides an engine equipped with means for injecting oil from the oil injection port provided at the small end of the connecting rod to the inner wall of the piston. A ring-shaped oil reservoir groove is formed on the outer periphery of the upper part (hereinafter referred to as the shoulder part) of the piston skirt located below the oil ring groove of An oil hole penetrating the reservoir groove is drilled, and the oil injected from the oil injection port provided at the small end of the connecting rod flows into the oil hole during the upward stroke of the piston, and during the downward stroke of the piston. An engine connection characterized in that an oil injection port is arranged at the small end of the connecting rod so that the oil is injected toward the inner wall of the piston at a position not communicating with the oil hole. Providing a piston lubrication system by the oil hole of the small end.

[0015]

[Operation] During the upward stroke of the piston, the oil injection flow injected from the small end injection port of the connecting rod flows into the oil hole formed in the inner wall of the piston opposite to the thrust side, flows out to the outside of the piston through the oil sump groove, The oil is lifted up by the oil ring to raise the piston, and the amount of oil is reduced.Furthermore, oil is filled between the piston anti-thrust side outer wall, which is pressed against the cylinder inner wall by lateral pressure, and the cylinder inner wall surface, forming an oil film. , Lubricate during this time so that the oil does not run out when the piston rises. During the piston lowering stroke, the direction of the oil jet is away from the direction toward the oil hole, and the jet of oil is entirely directed to the inner wall surface (back surface) of the piston, so that the inner surface of the piston is sufficiently cooled.

[0016]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1A shows a sectional view of the piston according to this embodiment and its vicinity, which corresponds to FIG. 7 of the prior art. The same parts as those in FIG. 7 are designated by the same reference numerals. In the figure, 1 is a piston, 2 is a piston pin, 3 is a connecting rod, 5 is a cylinder block, 6 is a cylinder head, 7 is a combustion chamber, 8 is a compression ring, 9 is an oil ring, 11 is a piston head, and 12 is a piston. A skirt portion, 13 is an oil ring groove, 15 is a piston thrust side outer wall, and 16 is a piston anti-thrust side outer wall.

A feature of the present embodiment with respect to the structure of the prior art described above is that an annular oil reservoir groove 14 is formed on the outer periphery of the shoulder 121 of the skirt portion 12 of the piston located below the oil ring groove 13 of the piston 1. Then, an oil hole (oil hole) 17 penetrating the oil reservoir groove 14 is bored from the inner side (back side) of the piston 1 on the anti-thrust side outer wall 16 of the piston, and the oil flow is guided to the oil hole 17. A guide groove 18 is provided in the piston skirt shoulder 121 adjacent to the oil hole 17. The connecting rod 3 is shown in FIG.
Similarly to the oil passage 34 and the connecting rod small end portion 31, an annular oil passage 35 is bored.
An oil jet port 38 is provided so as to communicate with 5. In the present embodiment, the position of the oil injection port 38 is different from that in FIG. 7, and when the connecting rod 3 is in the vertical position as shown in FIG. 1A, that is, the piston 1 is at the top dead center or the bottom dead center. When positioned at a point, the oil hole 17 is positioned and drilled so as to have a certain offset S.
That is, as shown in FIG. 1A, at the position of the oil injection port 38, the center line 381 is bored so as to have an offset amount of S with respect to the center line 171 of the oil hole 17. ..

FIG. 1 (b) is an oil reservoir groove 1 of FIG. 1 (a).
4 is an A view of the oil hole 17, and FIG. 1C is a B view of the piston skirt shoulder 121 and the guide groove 18.
The operation of the above configuration is shown in FIGS. FIG. 2 shows that when the center line of the connecting rod 3 makes an angle α with the Y-Y line (vertical line) connecting the centers of the piston pin 2 and the crankshaft 4 in the piston rising stroke (see also FIG. 4), the oil 2 shows the state in which the injection flow of is injected from the injection port 38 and flows into the oil hole 17. In this state, while the center line 381 of the injection port 38 is within the angle range of θ ₁ during the upward stroke of the piston, the oil flow is also guided by the guide groove 18 so that the jet flow passes through the oil hole 17 and is located outside the piston. The oil flows out into the oil sump groove 14, and a sufficiently thick oil film is formed between the piston skirt portion 16 and the cylinder inner wall surface 51, where the oil is scarcely scooped up by the oil ring 9 while the piston is rising. As shown in FIG. 4, since the anti-thrust side 16 of the piston is pressed against the inner wall surface of the cylinder during the upward stroke of the piston, the occurrence of abnormal wear and seizure caused by the oil film being cut off is prevented.

FIG. 3 shows the lowering stroke of the piston (FIG. 5).
See also). The state of the oil flow when the angle formed by the center line of the connecting rod 3 and the YY line is β is shown. During the piston lowering stroke, as shown in the drawing, the direction of the center line 381 of the oil injection port 38 moves within the angle range of θ ₂ which is deviated upward from the direction of the oil hole 17, so that the oil does not flow into the oil hole 17. As shown by the arrow in FIG. 3, the piston 1 is injected only on the inner side (back side) to cool the piston 1. At this time, since the piston is descending, the skirt portion 12 of the piston 1 and the cylinder inner wall 51
The space is filled with oil scraped off by the oil ring 9 so that there is no shortage, and the oil hole 1 is on the anti-thrust side.
The oil is not wasted because it is not supplied to 7, and because it is not on the crimp side as shown in FIG. 5, the oil runs short even if the oil is not replenished from the oil hole 17. There is no such thing.

According to the present invention, when the oil is injected into the piston by the connecting rod, as described above, the oil is replenished from the oil hole 17 of the piston to the anti-thrust side which is insufficient only in the piston ascending stroke, and During the descending stroke, all the oil is used to cool the piston. As a result, particularly when the piston needs to be cooled during the explosion stroke, sufficient oil is supplied to the back surface of the piston to effectively cool the piston. As described above, according to this embodiment, it is possible to effectively lubricate the piston without adversely affecting the cooling performance of the piston and the oil consumption. In particular, due to the above-mentioned fixed amount of offset S, the direction of the jet of oil is deviated from the oil hole 17 during the downward stroke of the piston, and the inflow of oil into the oil hole 17 is reliably prevented.

[0021]

The following effects can be obtained by implementing the present invention. (1) It is possible to sufficiently supply the oil to the piston anti-thrust side skirt portion from the connecting rod small end oil jet port during the upward stroke of the piston, which causes abnormal wear and scuffing on the skirt portion and the cylinder inner wall surface. The occurrence of image sticking and mirror finish is prevented. (2) All the oil supplied from the injection port during the piston lowering stroke is used for cooling the back surface of the piston, and the piston can be effectively cooled particularly during the explosion stroke. (3) In both of the cases (1) and (2), most of the oil is recovered, and the piston is sufficiently lubricated and cooled without adversely affecting the oil consumption.

[Brief description of drawings]

FIG. 1 shows a structure in the vicinity of a piston, a piston pin, and a connecting rod small end portion according to an embodiment of the present invention.
1A is a sectional view thereof, FIG. 1B is a view A of FIG. 1A, and FIG. 1C is a view B of FIG. 1A.

FIG. 2 is an explanatory diagram showing an oil supply action during a piston rising stroke in the piston shown in FIG.

FIG. 3 is an explanatory diagram showing an oil supply action during a piston descending stroke in the piston of FIG. 1.

FIG. 4 is a schematic view showing a contact state between the outer wall of the piston on the anti-thrust side and the inner wall surface of the cylinder during the piston ascending stroke of the conventional engine. FIG.
4B is a sectional view taken along line IV-IV of FIG.

FIG. 5 is a schematic view showing a contact state between a thrust side outer wall of a piston and a cylinder inner wall surface during a piston lowering stroke of a conventional engine, FIG. 5 (a) being a longitudinal sectional view and FIG. 5 (b).
FIG. 5 is a sectional view taken along line VV of FIG.

FIG. 6 is a cross-sectional view showing a path of a normal oil passage until oil is supplied to a piston via a connecting rod of a conventional engine.

7 is a partially enlarged view of a cross section taken along line I-I of FIG. 6 regarding a piston, a piston pin, and a connecting rod small end portion according to a conventional technique.

[Explanation of symbols]

 1 ... Piston 2 ... Piston pin 3 ... Connecting rod (connecting rod) 5 ... Cylinder block 51 ... Cylinder inner wall 7 ... Combustion chamber 9 ... Oil ring 11 ... Piston head 12 ... Piston skirt 121 ... Piston skirt top (shoulder) 13 ... Oil ring groove 14 ... Oil reservoir groove 15 ... Piston thrust side outer wall 16 ... Piston anti-thrust side outer wall 17 ... Oil hole (oil hole) 18 ... Guide groove 31 ... Connecting rod small end 37, 38 ... Oil jet port 381 ... Jet port Center line S ... Offset

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location F02F 3/22 A 8503-3G F16J 1/08 7366-3J

Claims (1)

[Claims] 1. An engine comprising means for injecting oil onto an inner wall (10) of a piston (1) from an oil injection port (38) provided at a small end (31) of a connecting rod (3). The upper part (12) of the skirt part (12) of the piston (1) located under the oil ring groove (13) of (1)
(1) An annular oil reservoir groove (14) is formed on the outer periphery of the piston (1), and the oil reservoir groove (14) is formed on the outer thrust side outer wall (16) of the piston (1) from the inner wall (10) of the piston (1).
An oil hole (17) is formed through the oil hole (17), and the oil injected from the oil injection port (38) provided at the connecting rod small end (31) is the oil hole (38) during the ascending stroke of the piston (1). 17) into the inner wall (10) of the piston (1) at a position where it does not communicate with the oil hole (17) during the downward stroke of the piston (1). A piston lubrication device using an oil injection port at a small end of a connecting rod of an engine, characterized in that an oil injection port (38) is provided in the portion (31).