DE2063651C - Pistons for internal combustion engines - Google Patents

Description

0.01 mm. For this purpose it is for example from the

5. Pistons for combustion power machines German patent application Sch 5976 I a / 46 c ', according to claims 1 to 4, characterized marked 3 ° P 20 63 ü51.5-13, known, on the circumference of the draws that the depth of the oil drag grooves 6 to piston skirt so-called oil drag grooves, which is a 12 μαι . semicircular, curved or sawtooth-shaped win-

6. Pistons for internal combustion engines have a kelsymmetrical profile, machining aufzubrinnach claims 1 to 5, characterized. When the piston enters the height of the shows that the smaller flank angle of the oil profile is initially due to the greater wear drag grooves on a piston for a four-strong worn. Although this wear and tear with an in-stroke internal combustion engine is limited to the piston taking contact portion of the profile, takes the shaft end is directed. the susceptibility of the piston to seizure, since

7. Pistons for internal combustion engines follow the Raufinach, which is reduced by wear claims 1 to 5, characterized by only relatively little lubricant in the oil, that the smaller flank angle of the oil drag grooves can hold. This is the training drag grooves in a piston for a two- one on the entire circumference of the piston skirt Cycle combustion engine to the piston crown hydrodynamic lubricating film when straightening up and down is. reverse motion of the piston is not always ensured.

8. Pistons for internal combustion engines 45 From British patent specification 349 248 are Fernach according to claims 1 to 7, characterized by being attached to the circumference of the piston skirt draws that in a known manner on the oil drag grooves with different sized flanks counter-pressure side the piston skirt of the smaller angle and the rounded flank angle running towards zero known from the oil drag grooves to the piston radii.

at the end of the shaft and on the pressure side to the piston 50

directed towards the ground. combustion engine from the crankshaft

lubricant thrown off as a result of their direction of rotation

- material almost exclusively on the cylinder liner in the

Reaches the area of the counterpressure scite of the piston.

55 This leads to the fact that in the ring belt on the opposite

The invention relates to a piston for the combustion pressure side, in particular in the area of the

tion engines with on the circumference of the shaft-side compression ring, an excess of

Piston skirt is offered machined rounded lubricant and therefore the

oil grooves, which have a sawtooth-like profile with a thick lubricating film in this area than on the

have an obtuse profile angle. 60 pressure side of the piston is formed. The printing

However, the working stroke of the piston in one combustion side is comparatively much higher

engine, a tiny combustion surface pressure flows through the thicker, hydro-

Flow rate at least to the upper compression dynamic lubricant film on the counterpressure side

ringing over. Since the compression rings are increased in addition, than the counter pressure side

the following bar is suspended again with the hot upper 65. One can therefore often observe that

The cylinder section in which combustion had previously started due to the insufficient lubricant supply.

followed, come into contact, the lubrication is the supply on the pressure side, especially on the

upper compression rings a complicated problem. piston head-side compression ring, burn marks,

3 »4

more or less large seizure marks and excess oil dragging would have been noticeably reduced average wear and tear occur. The sub- consequently remains in the oil drills

Different thicknesses of the lubricating film on the pressure and running-in of the piston, one for the formation of an opposing pressure side, also means that the oil scraper ring, which is uniformly thick on the circumference of the piston, receives the lubricant quantity required for a lubricant film g _t · when the piston moves downwards. the cylinder liner in the area of the counter-pressure stores, these advantages become all the more evident

Do not completely remove lubricant sticking to the side, the sharper the bottom of the groove of the oil drag

can. The remaining lubricant is coked and then grooved.

and the oil coke thus formed settles in a way that the smaller edge angle of the 01-

so that the formation of a hydrodynamic sclilepprillen in a piston for Vierlakt-Verbreiv

The lubricating film is disturbed and the wear and tear does not point towards the end of the piston skirt,

is increased significantly, causing the lubricant towards the

With a two-stroke engine there is the difficulty that crankshaft space is promoted,

the relatively small from the fuel mixture 15 with a piston for a two-stroke _; - Burning:>

The lubricant tantcil originating between the piston engine is the smaller flank angle of the

To hold the shaft and cylinder liner and point in the oil grooves to the piston crown, so dai.t

Conveying up the ring belt of the piston so that the lubricant moves towards the ring belt

a hydroclyna is conveyed up on the circumference of the piston skirt,

Mixer lubricant film can build up. 20 remains in the inventive oil drag pills

The invention has now set itself the task, even when the internal combustion engine is stopped.

which adhere to the aforementioned state of the art - such an amount of lubricant is stored that

to eliminate the defect and, in particular, to start immediately again a hydrodynamic Sclimi.-i

Can build up sawtooth-like profile with obtuse profile angles on film.

pointing on the circumference of the piston shaft spa- 25 Line, preferably a further development of the lirfindur and applied rounded oil drag grooves so. consists in that in itself from the German to design that when operating the combustion patent 437 422 known manner on the Ge engine a uniformly thick film of lubricant on the pressure side of the piston the smaller flankwm between the piston and the cylinder liner in front of the oil grooves / around The end of the piston skirt is to be handled so that both the pressure side and the pressure side face the piston head. In this Gegendrucksei'e always the same hydrodynamic way is achieved that on the Gegendruckseiic, pressure formation in the lubricating film is guaranteed and where the lubricant accumulation is greater than on the pressure also no more superfluous lubricant in the side, the lubricant to unlsn in the crank combustion chamber can get. Furthermore, the shaft space and on the pressure side upward in the lubricant consumption should be further reduced without the ring belt being promoted. At the same time, on the pressure side of the piston, there is one thing: the moderately thick lubricant film is undershot with a simultaneous lowering of the lubricant minimum. the lubricant consumption achieved.

This object is achieved according to the invention in the manner that the invention is illustrated in the drawings

solved that in known per se, represented towards zero and will be explained in more detail below. It

running radius of curvature and per se known 40 shows

th, different sized flank angles of FIG. 1 arranged in a cylinder 1 with Profile angle of the oil drag grooves 100 to 170 °, their piston 2 connected to a connecting rod 3 for a quadruple Fiankenwinkel 0.5 to 10 ° and their depth cycle internal combustion engine. According to Fig. La, 1 to 20 μm, with the profile angle of an enlarged section from FIG. 1 dai angle between the flanks of an oil drag groove 45 is the piston skirt with the invention and provided with Fiankenwinkel the angle between a trained oil drag grooves 4, the small flank of which an oil drag groove and the cylinder barrel flank angle directed towards the end of the piston skirt area is designated. and the bottom of the groove is sharp-edged.

The smaller flank angle of the oil drag grooves in FIG

preferably has a size of 1 to 5 °, in particular piston 2 connected to a connecting rod 3 for a two-

the other 2 to 3 °, while the profile angle of the oil-cycle internal combustion engine. According to FIG. 2

drag grooves preferably 130 to 170 °, in particular an enlarged section from FIG.

which is 150 to 170 °. The radius of curvature represents the piston skirt with the according to the invention

the bottom of the groove of the oil drag grooves is 0 to designed oil drag grooves 4, the smaller ones

0.1 mm, preferably 0 to 0.01 mm, 55 J flank angle directed to the piston head and their

As part of the further training, the invented groove base is sharp-edged.

tion is the depth of the oil drag grooves in particular

more 6 to 12 μm. a connecting rod 3 connected piston 2 for a four-

Darch the inventively designed on the cycle internal combustion engine. According to F ί g. 3 a Oil drag grooves attached to the piston skirt runs 60 and 3b, each with an enlarged section Abbot's curve, which represents the change in the bearing from FIG. 3, is the smaller flank angle part of the saw-tooth-like profiling through that of the oil drag grooves 4 on the counter-pressure line to the Represents wear, in a straight line from 0 to 100%, the piston skirt end straightened, while the smaller one means that even after a relatively small flank angle of the oil drag grooves 4 on the pressure wear the profile tips have a sufficiently large side to the piston crown. The Rillengnind of Have bearing portion without the depth of the oil drag grooves 4 being sharp-edged.

1 sheet of drawings

Claims (4)

1 2 /> * On the one hand, the ring assembly is intended to prevent * Patent claims · Lubricant from getting into the combustion chamber; on the other hand, the top compression ring must be like this 1. Pistons for internal combustion engines a lot of lubricant is available that this with 5 machined on the circumference of the piston skirt - despite the high operating temperature - still applied rounded oil grooves that are sufficiently lubricated. Sufficiently lubricated A sawtooth-like profile with a blunt profile means: the top ring must not have any burn marks have an angle, thereby getting even tiny feeding marks and its connection, that with per se known wear should be close to zero - just like the wear of the cylinder running end Radius of curvature and in and of itself admirably and Kclbcns - stay within the smallest limits, Known flank angles of different sizes. Sufficient lubrication in the area of the ring electrodes Profile angle of the oil drag grooves 100 to 170 °, partie is primarily determined by the training and their smaller flank angle 0.5 to 10 ° and their adhesion to a hydrodynamic lubricating film - Depth I be up to 20 μm. even with a sparse supply of lubricant - between 2. Pistons for internal combustion engines 15 see piston skirt and cylinder barrel "influenced, 'according to claim 1, characterized in that a hydrodynamic lubricating film the smaller flank angle of the oil drag grooves between the piston skirt and the cylinder 1 to 5 °, preferably 2 to 3 °. may form has been for several years in particular 3. Pistons for internal combustion engines of the piston skirt with a machined according to claims 1 and 2, characterized marked 20 minimum surface roughness, the roughness depth depending shows that the profile angle of the oil drag, depending on the engine type, is generally not less than 2 to 6 | in Grooves 130 to 170 °, preferably 150 to 170 °, is provided. Such a surface roughness is. on the one hand favors the running behavior of the 4. Pistons for internal combustion engine ;! bens by forming a lubricating film with the aid according to claims 1 to 3, characterized in that the lubricant is stored in the roughness depths draws that the radius of curvature of the oil and on the other hand limits the wear between dragging 0 to 0.1 mm, in particular 0 to the piston skirt and cylinder liner.