JPH04203675A - Combined oil ring - Google Patents

Abstract

PURPOSE:To secure a lubricating oil passage at time of high speed and load driving as well as to prevent any lubricating oil from being drawn up at time of engine braking by letting an upper projection of a spacer expander have a first ear angle and a lower projection have a second ear angle larger than the former, respectively. CONSTITUTION:An ear angle theta1 of an upper projection 5c is small in size as compared with another ear angle theta2 of a lower projection 5d, and side pressure of an upper side rail 1 is small as compared with that of a lower side rail 2. Consequently the upper side rail 1 is set free of contact with a top face 4a of the ring groove 4 with smaller force than that of the lower side rail 2, and a lubricating oil passage is formed at the side of a top face 1a of the upper side rail 1 from land pressure P1. On the other hand, the lower side rail 2 is made contact with the ring groove 4 with larger side pressure than that of the upper side rail 1, and even at time of applying such an engine brake that the inner part of a combustion chamber comes to negative pressure, upping motion of lubricating oil from the side of a crankcase is effectively sealed up.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to an oil ring used in an internal combustion engine, and more particularly to a combination oil ring in which a plurality of side rails are combined.

[Prior art] Piston rings for internal combustion engines usually consist of a pressure ring to ensure airtightness in the combustion chamber and a ring to scrape off lubricating oil such as engine oil adhering to the inner peripheral surface of the cylinder and collect it into the crank chamber. It consists of an oil ring.

If the lubricating oil scraping action by this oil ring is insufficient, lubricating oil will remain on the inner circumferential surface of the cylinder during the explosion stroke (combustion) of the internal combustion engine. As a result, the lubricating oil is burned together with the fuel and is wasted.

In order to efficiently scrape off lubricating oil with this oil ring, a combination oil ring was developed in which two side rails were incorporated into one spacer expander as described in Utility Model Publication No. 1-22918. has been done.

In this combination oil, as shown in FIG.
The side 5a is formed substantially parallel to the inner circumferential surface 3a of the cylinder 3, and the downward (crank chamber side) protrusion 5b is formed to be tilted in the axial direction of the cylinder 3 to provide a constant ear angle.

Therefore, the upper side rail 1 is supported substantially perpendicularly to the inner peripheral surface 3a of the cylinder, and the lower side rail 2 is supported at a constant angle to the inner peripheral surface 3a.

[Problems to be Solved by the Invention] Here, when the internal combustion engine is an automobile engine and engine braking is applied, the inside of the cylinder becomes negative pressure. In this situation, the above actual fairness 1-
In the combination oil ring as disclosed in No. 22918, the two side rails are always tensioned in the vertical direction, which effectively prevents lubricating oil from being sucked up due to negative pressure within the combustion chamber.

In other words, the upper side rail's upper surface is in surface contact with the upper surface of the ring groove, and the lower side rail's lower surface is in contact with the lower surface of the ring groove, so even when the combustion chamber becomes negative pressure, the crankshaft This can prevent lubricating oil from being sucked up from the chamber side to the combustion chamber side.

However, when operating the engine at high speed and high load,
Just before the end of the compression stroke, the upper part of the combination oil ring (
The upper surface of the upper side rail is separated from the upper surface of the ring groove by using the pressure between the pressure ring provided on the combustion chamber (combustion chamber side) and the upper side rail, and a lubricating oil passage is formed on the upper surface of the upper side rail. It is necessary to return the lubricating oil adhering to the surface to the crank chamber side through this lubricating oil passage and the drain hole 8.

In such a case, in the combination oil ring described in the above-mentioned Utility Model Publication No. 1-22918J+, the upper side rail 1 is attached to the cylinder inner circumferential surface 3a on the spacer expander 5 as shown in FIG. The ear angle of the upper protrusion 5a of the spacer expander 5 is O, and the upper side rail 1
The upper surface 1a seals the upper surface 4a of the ring groove 4 by surface contact. Therefore, the upper side rail 1 does not swing in the vertical direction, making it difficult to separate the upper side rail upper surface 1a from the upper surface 4a of the ring groove 4, making it difficult to secure a lubricating oil passage on the upper surface side of the upper side rail. I won't be able to do it.

Also, if the ear angle when supporting the side rail in the ring groove is large, the oil sealing performance will improve, but the side pressure (Fu) (Fig. 2) against the ring groove of the side rail will increase, so the upper side Problems arise in that it becomes difficult to separate the top surface of the rail from the top surface of the ring groove, and it becomes difficult to secure a lubricating oil passage on the top surface of the upper side rail.

Furthermore, it is known that the weight of the piston ring can be reduced by changing the piston ring configuration from the conventional three-ring configuration to the two-ring configuration, but with the conventional combination oil ring, lubricating oil consumption increases. It could not be used as a combination oil ring for two piston rings.

The combination oil ring of the present invention was developed in view of the above problems, and during high-speed, high-stress operation, a lubricating oil passage for returning lubricating oil to the crank chamber can be easily secured by pressure from the pressure ring side. To provide a combination ring which can effectively prevent lubricating oil from being sucked up from the crank chamber side when using an engine brake, etc.

[Means for Solving the Problems] To achieve the above object, the present invention comprises an upper side rail, a lower side rail, and a spacer expander having an upper protrusion and a lower protrusion inclined in the axial direction of the cylinder. a combination oil ring, wherein the upper protrusion of the spacer expander has a first ear angle that does not include O, and the lower protrusion of the spacer expander has a second ear angle that is larger than the first ear angle; The present invention provides a combination oil ring characterized by having an angle.

[For use] According to the combination oil ring of the present invention having the above configuration, since the ear angle on the combustion chamber side of the spacer expander is relatively small, the upper surface of the ring groove can be easily damaged even by pressure from the pressure ring (combustion chamber) side. The contact between the two parts is released and the seal at this part is released. As a result, a lubricating oil passage is formed on the upper surface of the upper side rail, and through this lubricating oil passage, the lubricating oil adhering to the upper inner peripheral surface of the cylinder on the upper side of the side rail is collected, which is especially necessary during high-speed, high-load operation. is easily performed.

On the other hand, since the ear angle on the crank chamber side of the spacer expander is larger than the ear angle on the combustion chamber side, it is also effective in sealing against lubricant oil sucking up from the crank chamber toward the combustion chamber, which is required when using engine braking. It will be held on.

[Example] Hereinafter, a combination ring according to an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a state in which the combination oil ring of this embodiment is adopted as a piston ring with three piston rings and is assembled into a piston 7.

The combination oil ring 10 of this embodiment includes an upper side rail 1, a lower side rail 2, and a spacer expander 5.
It consists of Above upper and lower side rails 1.2
Each of them has an annular shape. The upper side rail 1 is attached to an upper protrusion 5c formed on the combustion chamber side end of the spacer expander 5 with a predetermined ear angle toward the cylinder axis, and the lower side rail 2 is attached to the spacer expander 5. In a state in which each inner peripheral surface is in contact with a protrusion 5d formed at the crank chamber side end of the expander 5 so as to have an ear angle larger than the combustion chamber side ear angle toward the cylinder axis direction. Supported. As a result, as shown in Fig. 1, the combustion chamber side of the spacer expander 5 (upper side in Fig. 1)
The upper protrusion 5c ear angle θ is on the crank chamber side (first
(Bottom side of the figure) It is smaller than the ear ankle θ2 of the lower projection 5d.

The ear angle of the combustion chamber side upper projection 5c may be larger than Oo, but it is more preferably in the range of 5° to 15°, and the ear angle of the crank chamber side lower projection 5d is above the combustion chamber side. It is sufficient if it is larger than the protrusion 5c, and it is more preferable if it is in the range of 15° to 25°.

The combination oil ring 10 of this embodiment thus constructed is installed in the ring groove 4 provided on the outer peripheral surface of the piston 7, as shown in FIG. Therefore, the upper side rail 1 is supported at a predetermined angle with respect to the upper surface 4a of the ring groove 4, and as a result, a part of the upper surface 1a of the upper side rail 1 comes into contact with the upper surface of the ring #4. The upper side rail 1 prevents lubricating oil from rising due to the contact portion. Further, the lower side rail 2 is supported at a predetermined angle with respect to the lower surface 4b of the ring groove 4, and a part of the lower surface 2b of the lower side rail 2 is attached to the lower surface 4b of the ring groove 4.
b, and this contact portion also seals the lower side rail 2 from lubricating oil.

In FIG. 1, reference numerals 6 and 6 indicate two compression rings provided on the combustion chamber side of the combination oil ring of this embodiment to ensure airtightness within the combustion chamber, and 8 indicates the side rail 1. The drain holes for collecting the lubricating oil scraped off by .2 are shown respectively.

As described above, the ear angle θ of the upper projection 5c is smaller than the ear angle θ2 of the lower projection 5d. Therefore, the side pressure Fu of the upper side rail 1 is smaller than the side pressure Fu of the lower side rail 2. As a result, the upper side rail 1 exerts less force than the lower side rail 2 on the upper surface 4 of its ring 1114.
can be released from contact with a. As a result, a lubricating oil passage is formed on the upper surface 1a side of the side rail above the land pressure P1.

The lubricating oil adhering to the inner peripheral surface 3a of the cylinder 3 passes through this passage and reaches the inside of the drain hole 8. On the other hand, since the lower side rail 2 is brought into contact with the ring 1ll14 under a larger side pressure than the upper side rail 1, the crank chamber is kept in contact with the ring 1ll14 even when the combustion chamber is under negative pressure (i.e., during high boost). This effectively seals off the lubricating oil coming from the side (lower side in Figure 1).

The spacer expander 5 used in this embodiment is of a radially corrugated type, and the combination oil ring of the present invention is not limited to this, but may be of an axially corrugated type, an inner periphery open type, etc. It may be.

Further, in the above embodiment, the combination oil ring of the present invention is applied to a piston ring with three piston rings, but the combination oil ring of the present invention may also be applied to a piston ring with two piston rings.

"Effects" As described above, according to the combination oil link of the present invention, the side pressure against the ring groove of the upper side rail is weaker than the side pressure against the ring groove of the lower side seal.

Therefore, the seal against the ring groove of the upper side rail is easily broken by the pressure from the pressure ring (combustion chamber side), and a lubricating oil passage is formed on the upper surface of the upper side rail, and the lubricating oil passes through this passage and adheres to the inner peripheral surface of the cylinder. Lubricating oil will be collected. Particularly when the engine is operated at high speed and under high load, lubricating oil is efficiently recovered by the pressure generated between the compression ring and the upper side rail. Furthermore, when the combustion chamber is under negative pressure during engine braking, etc., the lower side rail seals the lower surface of the ring groove, effectively preventing lubricating oil from coming up from the crank chamber side.

Furthermore, when the combination oil ring of the present invention is applied to a piston ring with two piston rings including one compression ring, it can exhibit the same level of lubricating oil recovery ability as the three piston rings with a conventional combination oil ring. , and by reducing the number of compression rings by one, the engine can be made lighter and rotate at higher speeds, contributing to improved engine performance.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view showing a combination oil ring according to an embodiment of the present invention applied as an oil ring for a three-screw I/cylinder, and Fig. 2 is an upper side of the combination oil ring shown in Fig. 1. An explanatory view showing the state of the force acting on the side seal, FIG. 3 is a longitudinal sectional view of a conventional combination oil ring. In the figure, 1... upper side rail, 2... lower side rail, 3... cylinder, 4... ring groove, 5... spacer expander, 6... compression ring are shown. Patent applicant: Nippon Piston Ring Co., Ltd. Agent:
Patent attorney Kita, Hiroshi Sawa (and 1 other person) Figure 1b 4b rtsu-rQ('J

Claims (1)

[Scope of Claims] A combination oil ring composed of an upper side rail, a lower side rail, and a spacer expander having an upper projection and a lower projection inclined in the axial direction of the cylinder, the spacer expander comprising: A combination oil ring characterized in that the upper protrusion has a first ear angle not including zero, and the lower protrusion of the spacer expander has a second ear angle that is larger than the first ear angle.