JPH0322537Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a piston ring for a multi-stage composite abutment.

FIG. 1 shows the piston-cylinder configuration of a uniflow scavenging, two-stroke crosshead engine. In the figure, 1 is the exhaust valve, 2 is the cylinder cover, and 3 is the exhaust valve.
is a cylinder liner, 4 is a piston, 5 is a piston ring, and 6 is a piston rod. There are two types of piston rings 5 for diesel engines: pressure rings and oil rings.
A simple abutment (straight cut) as shown in the diagram
Alternatively, a diagonal abutment has been used, but recently a ring with a multi-stage composite abutment as shown in FIG. 3, which has good gas tightness, has been attempted.

As shown in Fig. 4, the airtight action of the piston rings is as follows: P ₁ is the pressure in the combustion chamber, P ₂ is the pressure between the 1st ring and the 2nd ring, and P 2 is the pressure between the 2nd ring and the 3rd ring. Assuming that the pressure is _P3 , the pressure change in one cycle for each pressure is as shown in FIG. 5 in the case of the simple abutment ring shown in FIG. 2, and the airtightness is insufficient. For this reason, when a multi-stage composite abutment ring as shown in Figure 3 is used, the first stage ring alone has very good airtightness as shown in Figure 6, and a large pressure difference between P ₁ and P ₂ is created. arise.

The conventional method described above has the following drawbacks.

The simple abutment ring shown in Figure 2 has the disadvantage of not being able to provide sufficient airtightness, while the multi-stage composite abutment ring shown in Figure 3 provides sufficient airtightness, but the contact pressure on the ring sliding surface is excessive. There are drawbacks to it. That is, in FIG. 4, the piston ring 51
The sliding surface pressure between the ring and the liner 3 is usually P ₁ and the ring back pressure P ₁ ′ in the figure are almost the same pressure (P ₁
≒P ₁ '), the surface pressure is proportional to P ₁ - _{P 2} /2, but in the case of a simple abutment ring, P ₁ - _{P 2} /2 is small, whereas the multistage composite abutment ring is airtight. Good sex,
As shown in FIG. 6, P ₁ -P ₂ /2 is very large, which results in excessive surface pressure, which has the disadvantage of causing excessive piston ring wear or cylinder liner wear.

The purpose of this invention is to focus on the above points and provide a piston ring that is airtight and has good lubricity.The main feature of this invention is that in a piston ring with a multi-stage composite abutment, the upper surface of the piston ring is An annular groove is provided along the circumferential direction of the ring, and a sub-piston ring that maintains airtightness between the lower surface of the piston ring groove and the piston ring is disposed within the annular groove, and the upper surface of the sub-piston ring is connected to the piston ring. This is because a spring that presses against the upper surface of the groove is interposed between the sub-piston ring and the annular groove.

The present invention can be applied to piston-type internal combustion engines, compressors, and expanders.

Embodiments of the present invention will be described below with reference to the drawings.

The present invention relates to a pressure ring among the piston rings of a piston type engine, and its structure is shown in Figure 7.
It is shown in FIG.

FIG. 7 shows a cross section of an embodiment of a piston ring according to the present invention.

In the figure, 3 is a cylinder liner, 4 is a piston, 51 is a piston ring, 511 is a groove provided on the upper surface of the piston ring, that is, an annular groove provided along the circumferential direction on the upper surface of the piston ring, 512 is a sub-piston ring, 513 indicates a spring that pushes up the sub-piston ring.

FIG. 8a is a perspective view showing the abutment, and the abutment has the shape of a multi-stage composite abutment. Figure 8b is Figure 7A
-A sectional view (circumferential sectional view).

The operation in the case of the above configuration will be described.

This piston ring has a multi-stage composite abutment and has excellent airtightness, but by providing the sub-piston ring 512 on the top surface, the ring back pressure is reduced.
P ₁ ' can be set such that P ₁ >P ₁ ' as shown in FIG.

For this reason, the sliding surface pressure between the piston ring 51 and the cylinder liner 3 in the conventional case (P ₁
〜P ₂ )/2, whereas in the present invention it becomes (P ₁ ′−(P ₁ +P ₂ )/2), and since P ₁ ′<P ₁ , (P ₁ −P ₂ )/2. 2>P ₁ ′−(P ₁ +P ₂ )/2, which is a significant decrease compared to the conventional one.

In particular, by optimizing the volume of the ring back surface and the area of the abutment part of the sub-piston ring 512, it is possible to control the ring back pressure _P1 ' and safely maintain the sliding surface load between the cylinder and the piston ring. can.

The above case has the following effects.

As described above, by providing the sub-piston ring on the top surface of the piston ring that has a multi-stage composite abutment, it is possible to maintain good airtightness, which is the original function of the piston ring, and to properly control the pressure on the back of the ring. Therefore, it is possible to maintain good lubricity between the cylinder and the piston ring, and it is possible to realize a highly economical engine with low fuel consumption and little piston ring and cylinder wear.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing the main parts of a conventional crosshead type engine, Fig. 2 a is a cross-sectional view showing a simple abutment of a piston ring, Fig. 2 b is a view taken in the direction of arrow A in Fig. 2 a, Figure c is a view taken from arrow B in Figure 2a, Figure 3a is a perspective view showing the multi-stage composite joint, Figure 3b is a side view of Figure 3a, and Figure 3c is a view of Figure 3a. Top view, 4th
The figure is an explanatory diagram showing the pressure in the piston ring section, 5th
The figure is a diagram showing the pressure change of a simple abutment ring, No. 6
The figure is a diagram showing pressure changes in a multi-stage composite ring.
The figure is a sectional view showing a piston ring according to an embodiment of the present invention, FIG. 8a is a perspective view showing the abutment part of the piston ring in FIG. 7, and FIG.
A sectional view taken in the direction of arrows, FIG. 9 is a diagram showing pressure changes in the piston ring according to the present invention. 51... Piston ring body, 511... Annular groove,
512...Sub-piston ring, 513...Spring.

Claims (1)

[Scope of utility model registration request] In a multi-stage composite abutment piston ring, an annular groove is provided on the upper surface of the piston ring along the circumferential direction of the ring, and a sub-piston ring that maintains airtightness between the piston ring groove lower surface and the piston ring is installed in the annular groove. A pinton ring, characterized in that a spring is interposed between the sub-piston ring and the annular groove, and presses the upper surface of the sub-piston ring against the upper surface of the piston ring groove.