FR2629870A1 - PISTON RING AND COMPRESSION SEGMENT ARRANGEMENT FOR INTERNAL COMBUSTION ENGINE - Google Patents

Abstract

The invention relates to a scraper and compression piston ring arrangement for an internal combustion engine. The arrangement comprises two twin rings 10 housed in the same segment groove CA of the piston P and separated by an intermediate compression ring 20 whose peripheral surface bears at least in part against the cylinder wall C, the twin rings 10 being pressed. radially outwardly against the cylinder wall C by a spring element 30 engaged in the segment groove CA. This arrangement allows the use of pistons with two piston rings only, because the twin rings 10 act as a scraper ring, while the intermediate separator ring 20 seals against oil and combustion gases.

Description

The present invention relates to a structure originally

  nal of scraper and compression segment for motor to

internal combustion.

  In the present state of the art, modern internal combustion engine pistons have segments that have the following three functions:

  1. Effectively establish gas tightness

  bustion (oppose that they seep beyond the piston). 2. Prevent an excess of lubricating oil

  does not reach the combustion chamber (oil control).

  3. Establish a heat conduction path of the

  piston to the water jacket of the cylinder.

  The first and third functions are assumed

  only by the compression segments, but the second one

  in fact, in combination with the segments, so many compro-

than scrapers.

  A typical segment set as known in the state of the art for four-stroke engines may comprise the assembly of a compression segment for the first groove of the piston, 1.5 mm wide; an intermediate segment for the second piston groove, also 1.5 mm wide and a scraper ring, for the third piston groove, in two or three pieces and 3.0 mmo wide over the past years and in any case until now, there were segments with more than three segments per piston, with a segment width of up to twice that indicated

above.

  The need to reduce weight, width,

  moving masses and friction in combustion engines

  internalization has led to a reduction in the number of segments

  piston as well as the width of segments.

  The object of the present invention is to provide an arrangement

  scraper and compression segment cement for a motor

  internal combustion to reduce the axial height

  the piston without compromising the efficiency of the latter.

  More particularly, the object of the invention is to provide a segment arrangement of the above-mentioned type which makes it possible to reduce the number of piston segment grooves without having to consequently reduce the efficiency of the segments necessary for the proper functioning of the piston. . These aspects and advantages of the invention, as well as

  others will be better understood from the description

  given below a preferred embodiment of a scraper and compression piston ring arrangement for an internal combustion engine, said arrangement comprising: - two twin rings engaged in a piston groove, each of which is contiguous to a wall corresponding side of the groove and carrying its peripheral surface against the cylinder wall of the engine; an intermediate compression ring mounted between the two paired rings so as to keep them separated

  and each bearing against a corresponding side wall

  the piston groove, this compression ring

  intermediary carrying at least part of his

  outside tower against the cylinder wall; and an element

  spring arranged at the bottom of the groove and simultaneously

  against the groove and against the two rings

  in order to apply these radially to the outside.

against the wall of the cylinder.

  The arrangement described above constitutes a set of elements that simultaneously play the roles of the prior art wiper and compression segments in the second and third grooves of the piston, allowing the use of pistons with only two grooves. and, therefore, a smaller axial dimension. In the proposed arrangement, the two twin rings pressed by the elementressort against the cylinder wall of the engine act in scraper segment while the intermediate ring, in addition to reinforcing the separation between

  the two paired rings, ensures as many seg-

  oil and flue gas tightness.

  The invention will now be described in detail with reference to the accompanying drawings, in which: FIG. 1 is a radial cross-sectional view of a

  part of an engine representing one of the cylinders

  internally carries a piston-segment assembly according to the invention; Figure 2 is a detail view in cross section of one of the two twin rings that comprises the arrangement according to Figure 1; Figs. 3A-3U are cross-sectional views of various intermediate ring shapes for use in the arrangement according to the present invention; FIGS. 4A and 4C are top plan views

  indicating various possible configurations of the element-

  spring used in the arrangement according to the present invention.

vention.

  As shown in FIG. 1, the arrangement according to the invention

  The invention comprises two twin rings 10, preferably of steel, coated, surface-treated or

  anti-wear thermochemical treatment, each ring

  being made in a normal way as indicated on the

  FIG. 2, its peripheral surface 13 being of toric form

  than and pressed against the cylinder wall C of the engine.

  The two paired rings 10 are mounted in the rim.

  AC-segment nipple formed in the piston P of the engine and thus replacing the second and third grooves A

segment known.

  According to FIG. 1, each paired ring 10 is placed against a corresponding side wall of the segment groove CA, its inner edge 14 being separated from the bottom of the groove CA and its peripheral surface 13 bearing

  against the cylinder wall C of the engine.

  Between the two paired rings 10 is inserted one year.-

  intermediate compression ring 20, usually made of cast iron or steel, dimensioned so that at least portions of its lateral surfaces 21 bear against the corresponding lateral surfaces 11 of the twin rings 10 in order to keep them in abutment against the side walls

  the AC segment groove. The international compression ring

  medial 20 is designed so that its inner surface 24 is offset radially inward relative to the inner slices 14 of the twin rings 10 and that nevertheless its peripheral surface 23 has at least one

  part in contact with the cylinder wall C of the engine.

  In other words, it can be said that the intermediate compression ring 20 has on at least part of its peripheral surface 23 a maximum diameter equal to the inside diameter of the cylinder C. FIGS. 3 to 3U represent as examples

  various configurations of intermediate compression ring

  20. Figures 3, 3A, 3B, 3D, 3E and 3F show intermediate compression rings having the following forms:

  with a frustoconical active face, of the positive torsion type

  tive 20 - with straight active face 20a - with frustoconical active face 20b

  with a rectilinear active face, of the positive torsion type

ve 20c

  with frustoconical active face, of the negative torsion type

  20d - 20f half-keystone 20f - 20f According to FIGS. 3G to 3U, these intermediate compression rings may have radial bevels 26,

  26a, 26b, 26c, 26d, 26e and 26f at the bottom of their lateral faces.

  or radial wedges 27, 27a, 27b, 27c, 27d, 27th

  and 27f at the top of their side faces.

  The fourth and last element of the assembly according to the invention is constituted by a spring element 30 placed inside the groove A segment CA so as to carry simultaneously, in the case of the springs shown in Figures 4A to 4C against the bottom of the AC segment groove and against the inner edge 14 of the twin rings to radially press these twin rings against the cylinder wall C of the engine, whereas in the case

2629870

  of the spring according to Figure 4, there is simultaneously support on the side wall of the groove CA and on the inner edge of

paired rings 10.

  These expansion springs 30 may have different configurations according to Figures 4 to 4C; in the illustrated examples, the spring may be in the form of a substantially oblong oblong metal band or ribbon, bent or not in length so as to press the radially coupled rings 10

outwards.

  In its preferred forms shown by way of example in FIGS. 4A to 4C, the expansion spring 30 is guided by the side walls of the CA segment groove, touching the bottom thereof and the inner slices 14 of the rings. 10 in a series of angularly spaced points, while in its form according to Figure 4, it does not touch the bottom of the groove

to CA segment.

  However, it must be understood that provision may be made

  elements-springs likely to have the same effect on the

paired rings 10.

  According to a development of the invention the metal strip

  the spring element is coated, superimposed

  anti-wear or anti-wear thermochemical treatment.

  The segment groove associated with the arrangement according to the invention

  may be situated at the location of the second reason

  segment of a common piston having three segment grooves.

Claims (11)

  1. Scraper piston ring and coupling arrangement   pressure for an internal combustion engine, characterized in   it comprises two twin rings (10) placed in the   the inside of a same segment groove (CA) in a piston (p), each paired ring (10) being juxtaposed to a corresponding side wall of the segment groove (CA) and carrying its peripheral surface (13) against the cylinder wall (C) of the engine; an intermediate compression ring (20) placed between the twin rings (10) so as to keep them separated and in contact each with the associated side wall of the segment groove (CA), the   said ring (20) carrying at least part of its sur-   peripheral face (23) against the cylinder wall (C);   and a spring element (30) engaged in the groove   (CA) and simultaneously bearing against the piston (P)   and against the twin rings (10) to press radially   the latter against the cylinder wall (C).   2. Scraper Piston Segment and Compartment Arrangement   pressure for an internal combustion engine, according to the   1, characterized in that the spring element (30) bears simultaneously on the bottom of the segment groove (CA) and on the inner edge (14) of the rings. semi-detached (10).   3. Scraper Piston Segment and Compartment Arrangement   pressure for an internal combustion engine, according to the   2, characterized in that the spring element (30)   door against the bottom of the segment groove (CA) and   the inner edge (14) of the twin rings (10)   in a series of angularly spaced points.   4. Scraper Piston Segment and Compression Arrangement   pressure for an internal combustion engine, according to the   1, characterized in that the spring element (30) bears against one of the side walls of the groove   segment (CA) and against the inner edge (14) of the twinned waters (10).   5. Piston ring arrangement and compaction   pressure for an internal combustion engine, according to the   1, characterized in that the spring element (30) is axially guided by the side wall of the groove A segment (CA).   6o Scraper Piston Segment and Compartment Arrangement   Internal combustion engine pressure according to Claim 1, characterized in that the spring element (30) consists of a metal strip interposed between the bottom of the groove A segment (CA) and the inner slice. (14) twin rings (10).   7. Scraper piston ring and coupling arrangement   pressure for an internal combustion engine, according to the   6, characterized in that the metal strip   bit a coating, a surface treatment-anti-wear or   a thermochemical anti-wear treatment.   8. Scraper Piston Segment and Compression Arrangement   pressure for an internal combustion engine, according to the   1, characterized in that the associated segment groove is located at the location of the second groove A segment of a current piston having three grooves A segment.   9. Scraper Piston Segment and Compound Arrangement   internal combustion engine pressure, according to the   1, characterized in that the intermediate compression ring (20) has its inner surface (24) offset radially outwards with respect to the alignment   peripheral surfaces (14) of the twin rings (10).   10. Scraper piston ring and coupling arrangement   internal combustion engine pressure, according to the   1, characterized in that the compression ring   intermediate (20) bears against the lateral faces   (11) twinned rings (10) by parts of 1 '   one or the other of its lateral faces (21).   11. Piston ring arrangement and coupling   pressure for an internal combustion engine, according to the   8, characterized in that one of the lateral faces   (21) of the intermediate compression ring (20)   radial wedges (26 A 26f and 27 A 27f).   12. Piston ring arrangement and coupling   pressure for an internal combustion engine, according to the   1, characterized in that the compression ring   intermediate (20) has one of the following configurations:   with frusto-conical face, of positive twist type (20); with straight face (20a); with frustoconical face (20b); to face   rectilinear, positive twist type (20c); face-to-face   conical, of the negative torsion type (20d); annular semi-keystone (20th); and annular neperian (20f) o