JPS599366A - Piston ring unit for engine - Google Patents

Abstract

PURPOSE:To improve the gas sealability of the piston ring unit for an engine by upwardly inclining the piston ring corresponding to a ring groove, and setting surface roughness from the lower surface of the piston ring and a gap to the ring groove to the prescribed range. CONSTITUTION:A piston ring 3 is formed in an upward inclination corresponding to the upward inclination of a ring groove 2. The surface roughness of the lower surface of the ring 3 becomes excessively smooth in case of 2mum or less, thereby deteriorating the oil retentivity, and wear of round unit 6 is accelerated in case of 7mum or more. When the gap 4 is formed to 25mum or less, the effective expanding operation of the ring 3 due to back pressure P1 is disturbed, and when it is formed 80mum or more, the ring 3 produces fluttering in the groove 2.

Description

[Detailed description of the invention] The present invention relates to a piston ring device for an engine.

Conventionally, in this type of device, a horizontal ring groove (2) is formed on the circumferential surface of the piston (1), as shown in No. 11, for example.
A piston ring (3) is fitted into this with a gap (4) in the vertical direction, and the pressure P0 from the combustion chamber is transferred to the gap (4).
Generally, a back pressure P1 is applied to the inner circumferential surface of the piston ring (3) through the piston ring (3), thereby expanding the piston ring (3) to obtain a seal between the piston ring (3) and the cylinder (5). However, in recent years, due to the demand for higher output and lighter engines, the piston (1) has become thinner and shorter, the ring round has been interposed, and the piston ring (3) has become thinner. On the other hand, the heat load tends to become severe, and in the above case, when the heat load is high, the round part (6) on the lower surface of the ring groove (2) has a downward direction as shown by the dotted line in Figure 1. This may cause blurring and problems such as ring stick.

Therefore, recently, as shown in Fig. 2, the ring groove (2) is formed in advance by slanting it upward to account for the amount of downward sagging of the round part (6) during high heat loads. However, in the case of the mouth, it is common to use a flat piston ring (3) as before, and according to this, the inner peripheral edge of the piston ring (3) and the ring @ (2) are generally used.
) Due to the contact with the upper surface, a back pressure p is applied to the inner circumferential surface of the ring (and the movement of the piston ring (3) becomes poor due to the contact with the upper surface, and the line between the piston ring (3) and the round part (6) Contact occurs and the sealing performance of the lower surface of the ring deteriorates, resulting in the inconvenience of an increase in the amount of blow pie due to gas escape.

The object of the present invention is to provide a device that eliminates such inconveniences, and in which the ring groove in which the piston ring fits on the circumferential surface of the piston of the engine is entirely inclined upward, the piston ring is inserted into the piston ring. The piston ring has an upwardly sloped shape corresponding to the slope of the ring groove, and the lower surface of the piston ring has a roughness of 1 fil + 2 to 7μ, and the gap in the heat direction when the piston ring is fitted into the ring groove. It is characterized in that it is set to 25 to 80μ.

Next, the present invention will be explained with reference to the illustrated embodiments.

FIGS. 3 and 4 show an example of the embodiment of the present invention, and in these figures, the same members as in the above-mentioned conventional example are given the same reference numerals as in FIGS. 1 and 2.

In the present invention, the piston ring (3) is formed with an upward slope corresponding to the upward slope of the ring i%1 (2), unlike the conventional flat ring, and these ring grooves (2)
The inclination angle of the piston ring (3) is set to 5 to 20 minutes, assuming the amount of sagging of the round portion (6) during high heat loads.

According to this, the piston ring (3) is placed in the round portion (6) while receiving the pressure P0 from the upper combustion chamber.
), and the ring m (2 + between the top surface and the upper surface @(
4) becomes uniform both inside and outside, and the piston ring (3)
) is applied to the inner circumferential surface of the
As a result, the piston ring (3) can be opened and expanded reliably, and the gas sealing property between the cylinder (5) and the wall surface is improved, and the gas sealing property of the lower surface of the piston ring (3) is also improved. Surface contact with the round part (6) is improved.

However, this effect cannot be obtained unless the surface roughness of the lower surface of the piston ring (3) and the dimensions of the gap (4) are properly controlled. Figure 6 shows data regarding the relationship between gap dimensions and blow pyro.

As is clear from Fig. 5, if the surface roughness is less than 2μ, the surface becomes too smooth, resulting in poor oil retention on the lower surface, poor downward gas sealing, and an increased amount of blow pie.
If it exceeds μ, wear of the round portion (6) will be accelerated and the amount of blowing will increase as well.

Furthermore, as is clear from Figure 6, the gap VA (41 is 25 μ
If this is done, the action of back pressure P is inhibited, and the cylinder (5
), the gas sealing between the piston ring (3) and the wall surface deteriorates, resulting in an increase in the amount of blow pie, and if the gap l is set to 80μ or more, a so-called fluff ring occurs in which the piston ring (3) dances within the ring groove (2), causing the same problem. Blow pie amount increases.

Therefore, the surface roughness should be 2 to 7μ (preferably 2 to 6μ),
Gap (4) is 20~80μ (preferably 40~60μ)
) is required.

In addition, when the ring groove (2) is provided in multiple stages above and below as shown in Fig. 3, the amount of sag becomes larger as the ring groove (2) is located on the upper side. It is desirable to make it as large as possible.

As described above, according to the present invention, the piston ring is made to have an upward slope corresponding to the ring groove, and the downward surface roughness of the piston ring and the gap with the ring groove are made to be within a predetermined range. As a result of this setting, the gas sealing property is significantly improved, and the above-mentioned disadvantages of the conventional type are avoided.

[Brief explanation of drawings]

1 and 2 are respectively cut-away side views of the main parts of a conventional device a, FIG. 5 is a cut-away side view of an example of the device of the present invention, and FIG. FIG. 5 is a diagram showing the relationship between surface roughness and the blow pyro amount, and FIG. 6 is a diagram showing the relationship between the gap and the blow pyro. (1)...Piston (2)...Ring groove (3)...Piston ring (4)...Outside the gap 2 people outside the gap Mr. Commissioner of the Japan Patent Office ■, Small case table 1977 Yearly weight τ1 Application No. 118138 2, Name of invention Engine piston ring device 3, Supplement 11: Relationship with the case of patent snoring 1 person 532 Honda Motor Co., Ltd. 4, agent Hitonakatari rllt port 1 Wifa 2'J 16th 1 Niko New W Hi' /L 7036υ02 Benri Go North
Interest - Telephone number 503-4811 (principal) - Correct.

Claims (1)

[Claims] In a device in which a ring groove for fitting a piston ring around a piston of an engine is inclined upward, the piston ring is formed to have an upward slope corresponding to the inclination of the ring groove, and 11 points are formed on the lower surface of the piston ring. A piston ring device for an engine, characterized in that the surface roughness is set to 2 to 7μ, and the vertical gap when the piston ring is fitted into the ring groove is set to 25 to 80μ.