JP2003532823A - Reciprocating piston engine - Google Patents

Abstract

(57) [Summary] The present invention relates to a reciprocating piston type engine having at least one piston 5. This piston is provided with at least one piston ring 6 in a corresponding piston ring notch 7 of the piston 5, said piston ring notch being provided with a support surface 8 corresponding to the piston ring 6. An object of the present invention is to improve the durability of the piston despite the high pressure at the portion of the support surface 8 and to promote the operation of reducing the wear. For this purpose, the piston ring 6 has, at least in a radially outer part of the lower surface facing the support surface 8, a plurality of recesses 14, which form a plurality of oil pockets 13 and an adjacent support area 18. 15 are provided. The oil pocket is formed by disposing filling members 16 and 17, at least a part of which is made of aluminum bronze having a wear resistance different from the wear resistance of the base material of the piston ring.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD OF THE INVENTION

The invention comprises at least one piston, which is provided with at least one piston ring in a corresponding piston ring notch of the piston, the notch having a bearing surface, which bearing surface comprises It relates to a reciprocating piston engine, in particular a two-stroke large diesel engine, which is provided corresponding to said piston ring and is preferably reinforced by a coating of chromium at least in its radially outer part.

[0002]

[Prior art]

The direction of the force acting on the piston ring changes due to the vertical movement of the piston. Therefore, vertical movement is excited in the piston ring. As a result, the corners on the radially outer side of the support surface of the piston ring notch are pressed very strongly, and the lubricating film may be damaged. Thus, smoothness is lost and significant wear occurs. In order to solve this problem, attempts have hitherto been made to provide a reinforcing film on the support surface, particularly in the radially outer portion. At this time, chromium is usually used. However, even in this case, the above-mentioned wear occurs,
The use of chromium has a particularly serious disadvantage here. This means that although a thin CrO layer with a hardness much higher than that of chromium is preferably formed on the surface of the chromium layer, as soon as this CrO layer is damaged, the much softer chromium is exposed. Therefore, the wear can proceed at a higher speed.

[0003]

[Problems to be Solved by the Invention]

In view of the above circumstances, an object of the present invention is to provide a simple and inexpensive method so as to obtain a wear-reduced operation and a long service life in spite of strong pressure on the support surface portion of the piston ring notch. Is to improve the configuration described at the beginning.

[0004]

[Means for Solving the Problems]

According to the present invention, the piston ring is provided with a plurality of recesses so as to form an oil pocket and a supporting region adjacent to the oil pocket at least at a lower outer radial portion facing the support surface. And a filling member disposed in these recesses, the filling member being formed at least in part from an aluminum bronze having a wear resistance different from that of the base material of the piston ring. Will be resolved.

In a new state, these recesses may be completely closed by the filling member provided. As a result, a smooth surface having no cross-sectional shape can be obtained which is easy to process. However, since the softer material wears faster, the desired oil pockets are already formed from the time of initial rolling during break-in. At this time, the depth of the oil pocket is very small in the desired method, but as the wear of the piston ring progresses, the oil pocket is formed in a range depending on this wear, whereby the total depth of the oil pocket is increased. The desired oil pocket will be present over the period of use. Lubricating oil can be stored in this oil pocket, which during a compressive stress causes a gap between the bearing surface of the piston ring notch surrounding the oil pocket and the bearing surface of the piston ring. Be pushed into. The oil pockets have a relatively shallow depth and therefore a relatively small volume, which in effect results in a thin oil film spreading over the entire piston ring surface, which results in a local increase in surface pressure. Disappears. From what has been stated above, it can be seen that the solution according to the invention solves the problem mentioned at the outset in a very simple and inexpensive manner.

Useful embodiments of the solution according to the upper claim, as well as preferred developments, are described in the subordinate claims. Thus, the material forming the filling member for the recess is
It may have a lower wear resistance than the base material of the piston ring, or a higher wear resistance. In the former case, the oil pocket is formed in the area of the recess where the filling member is provided. In the latter case, the oil pocket is formed in the region between the recesses where the filling member is provided. In the former case, the material that has fallen off the support surface can be forced into a relatively soft filling material and consequently fixed there.
According to this method, it is possible to prevent such a piece of material from moving around and thus prevent damage caused by the moving piece of material. In the latter case, it is possible to choose a material that is much harder than the base material of the piston ring, so that the progression of wear only proceeds at a very slow rate.

Aluminum bronze containing aluminum, iron, and copper can be preferably used as the filling material softer than the base material of the piston ring. To form a filler material that is harder than the piston ring substrate, aluminum, iron, manganese,
Aluminum bronze containing silicon, carbon, and copper can be preferably used.

[0008] In a further embodiment of the above feature, the plurality of recesses are, at least in part, a plurality of grooves spaced from one another and / or a plurality of blind holes evenly distributed over the surface on which they are disposed. Are formed from. In the former case, it is relatively easy to form, in the latter case a particularly good dispersion is achieved over each of the arranged surfaces.

According to a further useful solution, it is possible not to provide a recess in the radially inner part of the lower side of the piston ring. The effect of preventing gas passage can also be obtained by the filling member of the recess that wears more slowly in the radially inner portion of the lower side of the piston ring than in the outer portion. Then, it becomes possible to prevent the gas from passing through particularly reliably.

Further useful embodiments and preferred developments of the solution according to the upper claims are given in the other subclaims and can be understood from the following embodiments with reference to the drawings.

[0011]

DETAILED DESCRIPTION OF THE INVENTION

INDUSTRIAL APPLICATION This invention is used for a reciprocating piston type engine, especially a reciprocating piston type internal combustion engine, and is suitably used for a low-speed two-cycle large-sized diesel engine with a crosshead type structure. The structure and the workings of such a device are known per se and need not be described further here.

The cylinder of the two-stroke large diesel engine shown in FIG. 1 has a cylinder liner 2 provided with an intake slot 1, on which a cylinder head 3 of which only a part is shown is shown. , An exhaust device (not shown) is provided. The cylinder head forms the upper limit of the combustion chamber 4, and the lower limit of the combustion chamber 4 is formed by the piston 5. The piston 5 is arranged in the cylinder and is movable up and down. Although not shown in the drawing,
It is connected to the crosshead by a piston rod. This crosshead is
It is linked to the crankshaft via a connecting rod.

The piston 5 is provided with a set of piston rings comprising four piston rings 6. These piston rings 6 are, as can be seen from FIG. 2,
The piston ring notch 7 is provided on the piston skirt corresponding to each of them. The lower side of these piston rings 6 is then resting on the supporting surface 8 at the bottom of the corresponding piston ring notch 7. The outer peripheral surface of these piston rings 6 is formed as a sliding surface, and is closely fitted to the inner surface of the cylinder liner 2 which is also a sliding surface.

Lubricating oil is supplied to each sliding surface of the plurality of piston rings 6 and the sliding surface of the cylinder liner 2, and the plurality of piston rings 6 and the piston ring notches 7 provided corresponding to each of them are mutually provided. In order to supply the lubricating oil to the contact surface of the cylinder liner 2, the cylinder liner 2 can be provided with a radial lubricating oil hole 9 as shown in FIG. Meanwhile, the lubricating oil can be filled by a device not shown here.

Since each of the piston ring notches 7 is larger than the corresponding piston ring 6, the piston ring notch 7 is located on the upper side of the piston ring 7 and on the radially inner side of FIG.
A gap 10 is formed as can be seen from FIG. This gap 10 communicates with the combustion chamber 4 via a gap 11 between the piston 5 and the cylinder liner 2, and is therefore filled with combustion gas during operation. As a result, the radial force directed outward in the radial direction and the axial force directed downward act on the piston ring. This radial force pushes the piston ring 6 toward the cylinder liner 2. Due to the axial force, the piston ring 6 is pressed at its lower side towards the respective corresponding bearing surface 8. A frictional force acting downwards during the upward movement of the piston 5 and upwards during the downward movement of the piston is superimposed on the axial force generated by the pressure in the combustion chamber 4.

Due to this downward force, an extremely strong pressure is exerted between the lower side of the piston ring 6 and the supporting surface 8 of the corresponding notch. For that reason, the support surface 8 is preferably reinforced by a coating 12 of chromium. Chromium certainly has a strength of only about 300 HV. However, a thin CrO layer is formed on the surface of the chromium layer, and a much higher strength of about 800 HV is achieved, so that excellent durability characteristics are obtained.

Since the direction of the force changes during the vertical movement of the piston 5, the piston ring 6 behaves so as to slightly vibrate vertically. As a result, the pressure at the radially outer part of the support surface 8 is particularly high. This part has a width of about one third of the support surface 8. Without any additional measures, such pressure could damage the oil slick, causing the hard CrO layer to be lost very quickly, after which the relatively soft chromium is exposed and worn at a faster rate. Will progress.

To overcome the above problems, the piston ring 6 has at least a support surface 8
A plurality of oil pockets 13 are provided in the lower portion of the piston ring 6 facing the radially outer portion of the. These oil pockets 13 are shown only in FIG. 2 and are not visible, but the bearing area 1 illustrated in FIGS. 3 and 4.
It is adjacent to 8. These oil pockets 13 function as an oil tank.

In order to form the oil pocket 13, the piston ring 6 is provided with a recess 14 and / or a recess 15 in a lower portion thereof as shown in FIGS. 3 and 4.
A filling member 16 and / or a filling member 17 having wear resistance different from the wear resistance of the base material of the piston ring 6 is disposed in these recesses.

In the embodiment shown in FIG. 3, the filling member 16 of the recess 14 is formed of a material having a wear resistance lower than that of the base material of the piston ring. To form this filling member 16, aluminum bronze containing aluminum, iron, and copper can be used. At this time, 2 to 20%, especially 9 to 11
% Al, 0.5-8%, especially 0.5-2% Fe and the balance Cu.

In the new state, these recesses may be completely closed by the disposed filling member. As a result, a smooth surface having no cross-sectional shape can be obtained which is easy to process. On the other hand, due to the material of the filling member that wears faster than the base material, the desired oil pocket 13 is already formed from the time of initial rolling during the break-in operation. The oil pocket has a relatively shallow depth and thus acts as a relatively shallow oil tank.

The lower part of the piston ring, which lies outside the recess 14, forms the bearing area 18, as already mentioned above. Due to the shocking pressure, the oil stored in the oil pocket 13 is pushed to the side, and at this time, the oil is forced into the gap 19 between the bearing surface 8 of the piston ring notch and the bearing surface 18 of the piston ring. Pushed in. Since the volume of oil is relatively small and the depth of the oil pocket 13 is relatively shallow, at this time, a continuous thin oil film is formed over the entire supporting surface 8. This oil film spreads evenly over the entire support surface 8 so that, despite the provision of the oil pockets 13, the surface pressure at the bearing surface 18 does not increase locally.

In the embodiment shown in FIG. 4, the material forming the filling member 17 of the recess 15 has a wear resistance higher than that of the base material of the piston ring. At this time, in the new state, these recesses may also be completely closed. As a result, a smooth surface having no shape can be obtained which is easy to process. Here, due to the base material of the piston ring that wears faster than the material of the filling member, the desired oil pocket 1 has already started from the time of initial rolling during the break-in operation.
3 is formed between the plurality of filling members 17 of the plurality of recesses 15. Filling member 1
7 then wears as it is or very slowly and defines the oil pocket 13.

Here, as a suitable material, aluminum bronze containing at least aluminum, iron, manganese, silicon, carbon, and copper can be used. This material is 2-20% Al, 0.5-10% Fe, 0.1-8% Mn, =. 1% to 2%
Si, 0.1-10% Ni, =. 1% to 2% C, and Sb, Co, Be, Cr, Sn, Cd,
It is desirable that at least one of the components of Zn and Pb is contained in a maximum of 5 to 20% in each case, and further Cu is contained as the remaining component. In a particularly preferred case, 14
~ 17% Al, 3-5% Fe, 1-3% Mn, 0.1-2% Si, max 0.3%
C, and Cu as the remaining component.

The underside of the filler 17, which remains as it is, now forms the bearing surface 18 of the piston ring. Its function is the same as that already shown in FIG. In either case, as the wear of the piston ring progresses, the shallow oil pocket 13 is formed in a range depending on the wear. During the impact-induced compression, the oil stored in the oil pocket 13 is pushed into the gap 19 between the bearing surface 8 of the piston ring notch and the bearing surface 18 of the piston ring in film form. . Since the depth of the oil pocket 13 is shallow, the supporting surface 8
A thin oil film spreads evenly throughout.

The plurality of recesses 14 and / or recesses 15 described above may have any desired shape. That is, these concave portions may be formed as the groove portions 20 as shown in FIG. 5, or may be formed as blind holes 21 as shown in FIG. The plurality of groove portions 20 separated from each other have a shape extending in the radial direction,
Alternatively, it may have a curved shape as shown. As shown on the right side of FIG. 5, the groove portion 20 may extend over the entire width of the piston ring 6, or
Alternatively, it may be limited to the outer portion as shown on the left side of FIG. According to the later-described embodiment in which the groove is formed only in the outer portion, it becomes easier to prevent the gas from passing through unintentionally below the piston ring 6.

The plurality of blind holes 21 are preferably evenly distributed over the surface on which they are provided, which can also be distributed over the entire width of the piston ring, as shown on the left side of FIG. However, as shown on the right side of FIG. 6, it is possible to disperse the particles radially outward. In the present embodiment, the oil pocket 13 forms a so-called isolated island surrounded by the supporting surface 18, so that undesired passage of gas is always favorably prevented.

In order to ensure good distribution of oil on the outer peripheral side sliding surface portion of the piston ring 6, the piston ring 6 has a portion on the outer peripheral side sliding surface, as is apparent from FIG. In addition, at least one groove 22 extending in a direction that goes around the outer circumference may be provided. The groove 22 is separated from the surface of the upper side of the piston ring facing the cylinder head 3 by a web 24 that makes one continuous turn so as to form an oil pocket 23 along the entire circumference of the arranged piston ring 6. .

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a cylinder of a 2-cycle large diesel engine.

FIG. 2 is a sectional view showing a piston ring together with a corresponding piston ring notch provided therein.

FIG. 3 is an enlarged view showing portions of a piston ring and a piston ring notch that contact each other in an embodiment in which a soft filling member is provided in a recess.

FIG. 4 is a view similar to FIG. 3 in an embodiment in which a recess is provided with a hard filling member.

FIG. 5 is a plan view showing a lower surface of a piston ring having a groove-shaped recess.

FIG. 6 is a plan view showing a lower surface of a piston ring having a recess in the shape of a blind hole.

[Explanation of symbols]

  3 ... Cylinder head   5 ... Piston   6 ... Piston ring   7-Piston ring notch   8 ... Support surface   12 ... Chrome coating   13 ... oil pocket   14, 15 ... Recess   16, 17 ... Filling member   18 ... Support area   20 ... Groove   21 ... blind hole   23 ... oil pocket   24 ... Web

─────────────────────────────────────────────────── ─── Continued front page    (81) Designated countries EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, I T, LU, MC, NL, PT, SE), OA (BF, BJ , CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, K E, LS, MW, MZ, SD, SL, SZ, TZ, UG , ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AE, AG, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, BZ, C A, CH, CN, CR, CU, CZ, DE, DK, DM , DZ, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, JP, K E, KG, KP, KR, KZ, LC, LK, LR, LS , LT, LU, LV, MA, MD, MG, MK, MN, MW, MX, MZ, NO, NZ, PL, PT, RO, R U, SD, SE, SG, SI, SK, SL, TJ, TM , TR, TT, TZ, UA, UG, US, UZ, VN, YU, ZA, ZW

Claims (10)

[Claims] 1. A reciprocating piston engine, in particular a two-cycle large diesel engine, having at least one piston (5), which piston (5)
At least one piston ring (6) is arranged in a corresponding piston ring notch (7) of said piston (5), said notch having a bearing surface (8),
The bearing surface (8) is provided corresponding to the piston ring and preferably has a chromium coating (1) at least at its radially outer portion.
In the reciprocating piston engine reinforced by 2), the piston ring (6) has an oil pocket (13) and an oil pocket (13) at least at a lower radially outer portion facing the supporting surface (8). A plurality of recesses (14, 15) are provided so that a supporting region (18) adjacent to (13) is formed, and filling members (16, 17) are arranged in these recesses (14, 15). A reciprocating piston type engine, wherein the filling member (16, 17) is provided at least partially of aluminum bronze having a wear resistance different from that of the base material of the piston ring. . 2. The reciprocating piston engine according to claim 1, wherein the material forming the filling member (16) is entirely different in wear resistance from the wear resistance of the base material of the piston ring. A reciprocating piston type engine characterized by being made of aluminum bronze having. 3. The reciprocating piston type engine according to claim 1 or 2, wherein the material forming the filling member (16) has lower wear resistance than the base material of the piston ring. Characteristic reciprocating piston type engine. 4. The reciprocating piston type engine according to claim 3, wherein the aluminum bronze forming the filling member (16) contains at least aluminum, iron, and copper. Ceremony agency. 5. The reciprocating piston type engine according to claim 1, wherein the material forming the filling member (17) has higher wear resistance than the base material of the piston ring. Characteristic reciprocating piston type engine. 6. The reciprocating piston type engine according to claim 5, wherein the aluminum bronze forming the filling member (17) contains at least aluminum, iron, manganese, silicon, carbon, and copper. A reciprocating piston type engine. 7. The reciprocating piston type mechanism according to claim 1, wherein a plurality of the recesses provided to form the oil pocket (13) are provided.
A reciprocating piston engine characterized in that it is formed at least partially from a plurality of grooves (20) spaced apart from each other. 8. The reciprocating piston type mechanism according to claim 1, wherein a plurality of the recesses provided to form the oil pocket (13) are provided.
At least partially in the shape of a plurality of blind holes (21) spaced apart from each other,
A reciprocating piston engine, characterized in that these blind holes (21) are evenly distributed over the surface on which they are arranged. 9. The reciprocating piston type mechanism according to claim 1, wherein the lower portion of the piston ring (6) in the radial direction is not provided with the recess. Characteristic reciprocating piston type engine. 10. The reciprocating piston type mechanism according to any one of claims 1 to 9, wherein one or a plurality of piston rings (6) has a direction in which one or more piston rings (6) make one round at an outer peripheral side sliding surface portion thereof. There is provided at least one groove (22) extending to the cylinder head (22) so as to form an oil pocket (23) along the entire circumference of the arranged piston ring (6). From the surface above the piston ring facing 3),
A reciprocating piston engine characterized in that it is separated by a web (24) which makes one continuous turn.