阅读说明：本技术 用于三组件刮油环的刮刀环及三组件刮油环 (Scraper ring for three-component scraper ring and three-component scraper ring ) 是由 德克·巴伦罗伊特 尤尔根·吉伦 于 2019-07-18 设计创作，主要内容包括：公开了一种三组件刮油环,包括膨胀弹簧和两个刮刀环,刮刀环包括环体(4)。环体(4)具有上侧面(6)、下侧面(8)、环内表面(10)和环外表面(12),环外表面(12)在轴向(A)的横截面中具有环外轮廓(14)。其中,环体(4)具有高度H,对应于上侧面(6)到下侧面(8)的最大距离。其中环外轮廓(14)形成具有曲率半径R的运行表面(16),该曲率半径R比刮刀环(2)的高度H小1.5至6倍,优选地小3至5倍,更优选地小3.5至4.5倍。(A three-component scraper ring is disclosed, comprising an expansion spring and two scraper rings, which scraper rings comprise a ring body (4). The ring body (4) has an upper side (6), a lower side (8), an inner ring surface (10) and an outer ring surface (12), the outer ring surface (12) having an outer ring contour (14) in a cross section in the axial direction (A). Wherein the ring body (4) has a height H corresponding to the maximum distance of the upper side (6) to the lower side (8). Wherein the ring outer contour (14) forms a running surface (16) with a radius of curvature R which is 1.5 to 6 times smaller, preferably 3 to 5 times smaller, more preferably 3.5 to 4.5 times smaller than the height H of the scraper ring (2).)

1. A three-component oil scraper ring (28) comprising: an upper scraper ring (2) and a lower scraper ring (2), wherein the upper scraper ring (2) and the lower scraper ring (2) are kept at a distance by an expansion spring (34) and are pressed radially outwards, wherein the upper scraper ring and the lower scraper ring (2) comprise:

a ring body (4) having

An upper side surface (6),

a lower side surface (8),

an inner ring surface (10) and

a ring outer surface (12), the ring outer surface (12) having a ring-shaped outer contour (14) in a cross-section in an axial direction (A),

wherein the ring body (4) has a height H, which corresponds to the maximum distance of the upper side (6) from the lower side (8) when viewed in the axial direction (A), characterized in that the ring outer contour (14) forms a running surface (16) with a radius of curvature R, which is between 1.5 and 6 times, preferably between 3 and 5 times, more preferably between 3.5 and 4.5 times, smaller than the height H of the scraper ring (2),

wherein the scraper ring is symmetrical with respect to a plane extending along half of the scraper ring height H,

wherein the radially outermost position (18) of the ring outer contour (14) of the running surface (16) is located at half the height H/2 of the scraper ring (2),

wherein an upper/lower transition (22) is provided between the curvature with the radius of curvature R and the underside (8), the cross section of said upper/lower transition being convex and continuously and smoothly merging into the curvature.

2. The three-component scraper ring (28) according to claim 1, wherein the height H of the upper and lower scraper rings (2) is between 0.28 and 0.52 mm, preferably between 0.34 and 0.46 mm, and further preferably between 0.38 and 0.42 mm, wherein the radius of curvature R of the running surface (16) is between 0.06 and 0.04 mm, preferably between 0.08 and 0.12 mm, and further preferably between 0.09 and 0.11 mm.

3. The three-component oil scraper ring (28) according to claim 1 or 2, wherein an upper and a lower transition (22) are provided between the curvature with the radius of curvature R and the lower side (8), the cross section of the upper and lower transition (22) being designed as a convex surface and continuously and smoothly merging into the curvature.

4. The three-component scraper ring (28) according to claim 3, wherein an upper and a lower transition (22) between the curvature R and the lower side (8) have a curvature transition radius Ru which is between 1 and 40 times the height H, preferably between 2 and 20 times the height H, and further preferably between 4 and 10 times the height H.

5. The three-component oil scraper ring (28) according to claim 3, wherein the upper/lower transition (22) between the radius of curvature R and the lower side (8) is embodied in a sectional axial direction as a spiral curve, preferably as a hyperbolic spiral curve, which is preferably designed convex in cross section and merges continuously and smoothly into the curvature R and the lower side (8).

6. The three-component scraper ring (28) as claimed in any one of the preceding claims, wherein the expansion spring (34) is designed as an MF spring (36).

Technical Field

The present invention relates to a rail or scraper ring of a three-component scraper ring, and a scraper ring having such a rail.

Background

Oil scraper rings have been known for quite some time, in which various designs have been used. For example, single-component oil scraper rings having two scraper webs and having radial openings between the scraper webs in the scraper ring are known. Single-component oil scraper rings are also often used together with expansion springs in order to achieve as uniform a contact force as possible over the entire circumference and thus a scraping effect as uniform as possible. So-called three-component scraper rings are also known, in which two essentially disk-shaped or flat scraper rings or rails are held at a distance in the axial direction by means of springs in order to be pressed radially outward.

Various designs of oil scraper rings are known from patent documents US2016/0076649a1, US2017/0184198a1, EP3270012a1, DE112015001071T5 and JP H08-159282 a.

The oil scraper ring has parameters that affect the scraping performance.

In order to improve the scraping properties, it is particularly necessary to convey the oil in the direction of the groove base of the scraper piston ring. Hitherto, only the various slots and openings between the two scraper webs of the scraper ring have generally been taken into account in this respect.

It is necessary to further improve the scraping performance of the oil scraper ring.

Disclosure of Invention

The invention provides a multi-component oil scraper ring having the features of claim 1. Preferred embodiments are described in the dependent claims.

The invention provides a three-component oil scraper ring. The scraper ring includes two ring bodies having an upper side, a lower side, an inner ring surface, and an expansion spring. In this case, the upper side or scraper ring side should in each case bear axially against the piston ring groove side or against the spring of the three-component scraper ring. In this case, the lower side or scraper ring side should in each case bear axially against the piston ring groove side or the spring of the three-component scraper ring. The inner ring surface at this end is intended to radially abut against a spring or expansion means on the three-component oil scraper ring.

The ring outer surface has, in axial cross section, a ring outer contour which is intended to pass through the axis of rotational symmetry.

The ring body has a height H in the axial direction, which corresponds to the maximum distance of the upper side surface from the lower side surface in the axial direction.

The ring outer contour forms a running surface, wherein the ring outer contour has a radius of curvature R which is smaller than the height H of the scraper ring by a factor of between 1.5 and 6, preferably by a factor of between 3 and 5, more preferably by a factor of between 3.5 and 4.5.

Like all piston rings, scraper rings and oil scraper rings, the ring body also comprises a ring joint.

The scraper ring is characterized in particular in that, in the region of contact of the scraper ring with the inner surface of the cylinder, the scraper ring has a radius of curvature which is significantly smaller than half the height of the respective scraper ring. This aspect of the invention is particularly concerned only with the scraper ring of a three-component scraper ring.

In an exemplary embodiment, the scraper ring is symmetrical with respect to its plane extending along half of the height H of the scraper ring.

In an exemplary embodiment of the scraper ring, the height H of the scraper ring is between 0.28 mm and 0.52 mm, preferably between 0.34 mm and 0.46 mm, and further preferably between 0.38 and 0.42 mm. Exemplary embodiments also disclose that the running surface has a radius of curvature R that is between 0.06 mm and 0.04 mm, preferably between 0.08 mm and 0.12 mm, and further preferably between 0.09 mm and 0.11 mm.

In another exemplary embodiment of the scraper ring, the height H of the scraper ring is between 0.28 mm and 0.52 mm and the radius of curvature R of the running surface is between 0.06 mm and 0.04 mm. In another exemplary embodiment of the scraper ring, the height H of the scraper ring is between 0.34 mm and 0.46 mm and the radius of curvature R of the running surface is between 0.08 mm and 0.12 mm. In another exemplary embodiment of the scraper ring, the height H of the scraper ring is between 0.38 mm and 0.42 mm and the radius of curvature R of the running surface is between 0.09 mm and 0.11 mm.

In another exemplary embodiment of the scraper ring, the radially outermost point of the ring outer contour of the running surface is located at half the height H/2 of the scraper ring. Here, the scraper ring is arranged to be centrally in contact with the inner surface of the cylinder body when viewed in the axial direction. The scraper ring has no tendency to twist in this way.

In another exemplary embodiment of the scraper ring, a transition is provided between the curvature with the radius of curvature R and the underside. The cross section of the transition is convex and transitions continuously and smoothly into the curvature R. Thus, the un-scraped oil adhering to the running surface of the scraper ring, which has passed through the gap between the cylinder inner wall and the running surface having the radius R, should be deflected inward in the direction of the groove base on the rear side of the radius of curvature R. This is particularly effective on the upper scraper ring of a three-component scraper ring as the piston moves upwardly.

In a further exemplary embodiment of the doctor ring, a transition is provided between the curvature R and the upper side, wherein the cross section is designed to be convex and continuously smoothly merges into the curvature R. Likewise, the un-scraped oil that has passed through the gap between the cylinder inner wall and the running surface having the curvature R, adhering to the running surface of the scraper ring, should be deflected inward in the direction of the groove base on the rear side of the curvature R. This is particularly effective on the lower scraper ring of a three-component scraper ring when the piston is moving downward.

In a further exemplary embodiment of the scraper ring, the transition between the curvature R and the underside has a curvature transition radius Ru which is between 1 and 40 times the height H, preferably between 2 and 20 times the height H, more preferably between 4 and 10 times the height H. The design also involves the transition between the curvature R and the upper side if the design is symmetrical. In this design, a smaller fillet radius may also be present between the transition region and the upper side.

In another exemplary embodiment of the scraper ring, the ring outer surface extends radially beyond a region which occupies between 1/5 and 4/5 of the height H, preferably between 1/4 and 3/4 of the height H, and even more preferably between 1/3 and 1/2 of the height H. In this case, the width of the tapered region on the outside or running surface of the scraper ring does not extend to the height of the ring.

In a further exemplary embodiment of the blade ring, the transition between the curvature R and the underside is embodied as a spiral curve, preferably as a hyperbolic spiral curve, in cross section. The spiral curve is preferably embodied as a convex curve in cross section and continuously and smoothly merges into the curvature R and the flank. In this case, the oil flowing along the spiral curve can be deflected better in the direction of the groove base as a result of the gradual change in the radius of curvature along the latter, so that the deflection of the oil in the direction of the groove base is improved.

In a symmetrical design, this also relates to the transition between the curvature R and the upper side, which then also follows a spiral curve.

In another embodiment of the scraper ring, the scraper ring is an upper scraper ring of a three-component piston ring.

According to another aspect, embodiments of a scraper ring are claimed, wherein the radially outermost position of the ring outer contour of the running surface is located at a height of the scraper ring, which height corresponds to the value of the radius of curvature R of the running surface, and wherein preferably the radius of curvature R of the running surface merges continuously and smoothly into the underside.

In the cross section, the radius of curvature is directly connected to the underside, since the circle defined by the radius of curvature R is tangent to the underside (viewed in cross section).

In a further exemplary embodiment of the doctor ring, the upper side at the outer edge transitions continuously and smoothly into a curvature Ro in cross section, which is smaller than the curvature R of the running surface, wherein the radii of curvature R and Ro are connected by a common tangent. The two radii of curvature and the tangent line together form an annular outer surface. In a complete circle, the tangent line will form a truncated conical surface that tapers upward. The upper and lower radii of curvature each form a subsurface of a torus.

In another exemplary embodiment of the scraper ring, the radii of curvature R and the mid-point of Ro lie on a straight line in the cross-section, which straight line is parallel to the axial direction of the scraper ring.

Thus, two pitch circles with radii R and Ro are obtained, which are interconnected by a tangent portion. The pitch circle having radii R and Ro has an overall angle of 180 °. The pitch circle with radius R extends over an angle of more than 90 °. The pitch circle with the radius R preferably extends over an angular range of between 95 ° and 115 °, preferably between 98 ° and 110 °, and further preferably between 100 ° and 105 °. The pitch circle with radius Ro extends over an angle of less than 90 deg.. The pitch circle with the radius Ro preferably extends over an angle of between 65 ° and 85 °, preferably between 70 ° and 82 °, and further preferably between 75 ° and 80 °.

The tangent to the upper scraper ring in the cross-section herein is defined as the root of the sum of the squares of the difference of the radii R and Ro and the sum of the squares of the difference of the radii and the height H.

In this case, the angle of the conical surface resulting from the rotation of the tangent portion about the axis of the scraper ring is between 5 ° and 25 °, preferably in the angular range of 8 ° to 20 °, and further preferably in an angular range of 10 ° and 15 °.

In this embodiment, the upper ring side smoothly and continuously engages the curvature Ro, which in turn smoothly and continuously engages the tangent portion, which in turn smoothly and continuously engages the curvature R of the running surface, and then eventually smoothly and continuously enters the lower side. The two radii of curvature and the tangent line together form an annular outer surface. In a complete circle, the tangent line will form a truncated conical surface that tapers upward.

In another exemplary embodiment of the scraper ring, the radially outermost position of the ring outer contour of the running surface is located at the height R of the scraper ring measured from its ring underside, and further the transition between the ring undersides, the radius of curvature R, the radius of curvature Ro and the upper side of the tangent line section are in each case continuously and smoothly connected. The radially outer surface comprises, in cross-section, two circular arcs and a line segment, in which there are no ridges.

The ring outer surface preferably has an axial extension R, i.e. a lower radius of curvature R of the running surface.

In another exemplary embodiment of the scraper ring, the scraper ring is an upper scraper ring of a three-component piston ring. In particular, the shape of the scraper ring is such that the scraper ring floats on the oil layer particularly well during the upward movement of the piston.

According to another aspect, an exemplary embodiment of a scraper ring for a three-component scraper ring is provided, wherein the value R of the radius of curvature is smaller than the height H of the scraper ring by a factor of 1.5 to 4, preferably by a factor of between 1.8 and 3, and further preferably by a factor of between 2 and 2.5. This embodiment relates to a scraper ring having a relatively large radius of curvature R.

In another exemplary embodiment of the scraper ring, the radius of curvature R is between 0.03 and 0.2 mm, preferably between 0.04 and 0.15 mm, and further preferably between 0.05 and 0.10 mm, and the height H of the scraper ring is between 0.2 and 0.8 mm, preferably between 0.25 and 0.15 mm, and further preferably between 0.3 and 0.5 mm.

In another exemplary embodiment of the scraper ring, the radius of curvature R is between 0.03 and 0.2 mm and the height H of the scraper ring is between 0.2 and 0.8 mm. In another exemplary embodiment of the scraper ring, the radius of curvature R is between 0.04 and 0.15 mm and the height H of the scraper ring is between 0.25 and 0.15 mm. In another exemplary embodiment of the scraper ring, the radius of curvature R is between 0.05 and 0.10 mm and the height H of the scraper ring is between 0.3 and 05 mm. These combinations are also considered to be particularly promising for good scraping effect.

In another exemplary embodiment of the scraper ring, the radially outermost point of the ring outer contour of the running surface is located between 55% and 80%, preferably between 50% and 75%, further preferably between 65% and 70% of the scraper ring height H. The scraper ring is thus pressed at one point against the inner surface of the cylinder above the centre of the scraper ring. This results in distortion of the scraper ring.

In a further embodiment of the scraper ring, a lower transition and an upper transition are provided between the curvature R and the lower or upper side, respectively, which form a tangent line in cross section at the radius of curvature R, respectively, and each extend in the direction of the upper or lower side at an angle of between 30 ° and 75 ° with respect to a radial plane.

The transition is designed to be essentially straight, wherein a corner or edge can also be rounded between the upper transition and the lower transition. The ring outer surface is formed here essentially by a circular arc and two tangent portions, which may be designed as upper transition tangents or as lower transition tangents.

In a further exemplary embodiment of the scraper ring, the positions of the upper or lower transition into the upper or lower side respectively overlap each other in the axial direction or are at the same radial distance from the axis of symmetry.

In a further embodiment of the scraper ring, a lower and an upper helical transition are provided between the radius of curvature R and the lower or upper side of the lower scraper ring, respectively, wherein the helical transitions transition smoothly and continuously into the curvature R or the upper/lower side, respectively. This embodiment makes the curvature of the running surface and the transition between the piston ring sides more uniform than a straight section.

A straight spiral transition may provide an improved flow of scraped oil in the direction of the base of the piston ring groove. The helical transition here relates to a section in the axial direction. The helical transition is embodied in this case as a helical curve, preferably as a hyperbolic helical curve. The transition is convex in design, preferably continuously and smoothly merges into the radius of curvature R and the flank surface.

In an additional embodiment of the scraper ring, the scraper ring is a lower scraper ring of a three-component piston ring. In an additional embodiment of the scraper ring, the scraper ring is an upper scraper ring of a three-component piston ring. In an additional exemplary embodiment of the scraper ring, the scraper ring is a lower scraper ring and an upper scraper ring of a three-component piston ring, wherein the scraper ring can be used in both positions.

According to a further aspect, exemplary embodiments of a three-component scraper ring are provided, wherein in each case, as described above, an upper scraper ring and a lower scraper ring are used, wherein the scraper rings are held at a distance by an expansion spring and are pressed radially outwards.

In the exemplary embodiment of a three-component oil scraper ring, the same oil scraper ring as described above is used in each case.

In another exemplary embodiment of a three-component oil scraper ring, an upper scraper ring having two radii of curvature and a tangent therebetween as previously described is used, but a lower scraper ring having one radius of curvature and two straight or helical transitions as previously described is used.

It is worth noting here that the two loops are twisted in opposite directions each.

Additionally, in this embodiment, the contact points or lines of the scraper ring are closer together than the spacing of the respective center planes of the scraper ring.

In another exemplary embodiment of the three-component oil scraper ring, the expansion spring is embodied as an MF spring. In particular, the MF expansion spring allows a particularly good oil passage in the radial direction, since it covers only a small part of the gap between the upper and lower oil scraper rings, compared to the SS50 and MD expansion springs.

Drawings

The invention is described below with reference to the drawings of preferred embodiments.

Fig. 1 shows a cross-sectional view of a conventional scraper ring.

Fig. 2 shows a sectional view of a scraper ring according to a first embodiment of the present invention.

Fig. 3 shows a cross-sectional view of a conventional three-component oil scraper ring.

Fig. 4 shows a sectional view of a scraper ring according to a second embodiment of the present invention.

Fig. 5 shows a sectional view of a scraper ring according to a third embodiment of the present invention.

Fig. 6 shows a cross-sectional view of a three-component scraper ring having a scraper ring according to the present invention.

Fig. 7 shows a cross-sectional view of a three-component scraper ring having a scraper ring according to the present invention.

The figures are schematic and not to scale. The same or similar reference numbers are used throughout the description and drawings to refer to the same or like parts or elements.

Detailed Description

Fig. 1 shows a cross-sectional view of a conventional scraper ring 42. The scraper ring comprises a ring body 4, which ring body 4 is delimited at the top by an upper or lateral surface 6 and at the bottom by a lower lateral surface 8. The outer contour of the ring has a uniform radius of curvature Rsdt. The radius of curvature forms the running surface 12 of the scraper ring. In this case, the distance of the upper and lower side surfaces determines the height H of the scraper ring. In this case, the uniform radius of curvature Rsdt is exactly half the height H of the scraper ring. The scraper performance of the scraper ring is affected by variations in the height and material of the ring and mainly by the radial thickness and the performance of the expansion springs used. The scraper ring according to the prior art has an outer radius Rsdt substantially corresponding to a semicircle, which points towards the cylinder inner surface, which corresponds to half the height.

Fig. 2 shows a sectional view of a scraper ring according to a first embodiment of the present invention. The scraper ring 26 comprises a ring body 4, the ring body 4 being bounded at the top by an upper or side surface 6 and at the bottom by a lower side surface 8. Here, the height H is also determined by the distance of the upper and lower sides. The ring outer side 12 comprises a ring outer contour 14 which is axial in cross section and passes through the axis of symmetry.

The ring outer contour 14 forms a running surface 16 with a radius of curvature R which is significantly smaller than the height H. The radius of curvature is less than between 3.5 and 4.5 times the height H of the scraper ring 2. The radius of curvature R of the running surface 16 continuously and smoothly merges into a transition 20 between the curvature R and the upper side and into a transition 22 between the curvature R and the lower side. The radius of curvature of each of the transitions 20 and 22 may be much greater than the height H. Edge rounding is also provided which may occur between the transitions 20 and 22 and the sides 6 and 8. In general, the ring outer surface is formed as a combination of three radii, i.e. a radius of curvature line R of the running surface, which joins up/down the transitions 20, 22 with a transition radius of curvature Ru. The radially outermost position or pivot point 18 of the ring outer contour of the running surface 16 forms the contact point of the ring outer contour 14. In the complete scraper ring 2, the contact point thus forms a contact line. In order to reduce oil consumption, the profile of the running surface is optimized.

In the shown scraper ring, the area adjoining the cylinder inner wall has a significantly smaller radius of curvature than the scraper ring of the prior art. The curvature R should here be in the range from 0.08 mm to 0.12 mm. The transition regions 20 and 22 are preferably 0.75 mm. The distance r describing the radial extension of the ring outer surface 12 is between 0.1 and 0.2 mm and in fig. 2 should be 0.15 mm. The outer contour of the scraper ring is mirror-symmetrical with respect to a plane through the scraper ring at half height H. The new ring outer contour shows advantages in terms of oil consumption both under simulation and under use conditions.

Fig. 3 shows a cross-sectional view of a conventional three-component oil scraper ring 44. The conventional oil scraper ring 44 includes an upper scraper ring 42 and a lower scraper ring 42. Both scraper rings are designed as conventional scraper rings 42. Both conventional scraper rings 42 are pressed outwards by the expansion spring 34 in the direction of the cylinder inner wall 38. The expansion spring 34 also ensures that the two conventional scraper rings 42 are kept at a sufficient distance in the axial direction. To date, three-component oil scraper rings currently on the market use various scraper rings. However, up to now, rings having the same outer contour, i.e. scraper rings having the same radius of curvature, have been used as the upper scraper ring and the lower scraper ring. The two scraper rings scrape oil on the scraper cylinder inner wall 38 in the same way. Here, the scraping process is shown as an upward movement AA. Since the scraper ring is of symmetrical design, the drawing corresponds to the case of downward movement, so it is precisely the case that upward movement should occur.

The object is to obtain an improved oil scraping effect and/or a minimum friction loss compared to a conventional oil scraper ring having identical upper and lower scraper rings. Another important aspect is the avoidance or at least significant reduction of oil coke formation and deposition in the expansion spring region. Furthermore, it is desirable to achieve that the friction generated by the oil scraper ring does not have a significant adverse effect on the oil consumption.

Fig. 4 shows a sectional view of a scraper ring according to a second embodiment of the present invention.

In contrast to the scraper ring shown in fig. 1, the scraper ring shown in fig. 4 is asymmetrical with respect to a plane extending through the piston ring at half the height H.

Fig. 4 shows a sectional view through the blade ring 2 with the ring body 4, wherein the ring body 4 is delimited at the top by an upper side or flank 6 and at the bottom by a lower side 8. The ring body is delimited on the inside by an inner ring surface 10. The ring inner surface 10 is disposed opposite the ring outer side 12. The ring outer side 12 forms a ring outer contour 14. The curvature R forms a running surface 16 on the ring outer contour 14. The curvature R merges continuously and smoothly into the underside 8 or the underside, forming a tangent to the radius of curvature R. The curvature extends over 90 deg., so that the curvature R forms the radially outermost position or pivot point 18 of the ring outer contour of the running surface 16. In this case the pivot point 18 is located a distance R above the side of the under-scraper ring. The curvature R of the profile then continues directly and smoothly into a straight line segment, through which a truncated conical flank is formed on the scraper ring. The tangent line segment joins an upper radius of curvature Ro that is tangent to both the tangent portion and the line of intersection of the upper flanks. In this case, the radius Ro is smaller than the radius R. The tangent line segment is here the common tangent T of the radii of curvature R and Ro. In this embodiment, the centers of the radii of curvature R and Ro precisely overlap each other in the axial direction so that the truncated conical sides converge upward.

The pivot point 18 of the asymmetric conical track or scraper ring is offset in a direction offset from the underside. The pivot point is located at 20% to 40% of the axial height H. The value of the radius of curvature R thus corresponds to two fifths to one half of the height H. The upper blade ring axial height is maintained in the range of 0.3 to 0.5 mm. Furthermore, the outer contour of the scraper ring is determined by the dimensions of the radius of curvature R and the angle α. The angle α is the angle between the cone angle or the common tangent of the radii of curvature R and Ro of the truncated conical sides and the axial direction. Here, the radius will be between 0.15 and 0.25 mm, and the angle α between 5 and 20 °. The radius Ro may be between 0.1 and 0.2 mm. The scraper ring should be used as an upper scraper ring.

Fig. 5 shows a sectional view of a scraper ring according to a third embodiment of the present invention. Here, a scraper ring with a running surface 16 is provided, which is designed as a symmetrical spherical surface in the region of the pivot point 18. However, the pivot point is located above the central plane H/2. The pivot point 18 is located at an axial height between 55 and 75% of the height H when viewed from the underside. The radius R of the convex surface defining the running surface may be in the range 0.05 to 0.15 mm. The radius of curvature R is tangent upwardly and downwardly to the upper transition tangent 30 and the lower transition tangent 32, respectively. In this case, the transition tangent may have an angle of between 30 ° and 75 ° with respect to the axial direction. The transition tangents 30 and 32 enter the upper or lower side, which may be rounded, by bending. The profile of the scraper ring shows reduced friction.

Fig. 6 shows a cross-sectional view of a three-component scraper ring having a scraper ring according to the present invention. The three-component oil scraper ring comprises an upper scraper ring 24, which is implemented according to the embodiment of fig. 4. The three-component oil scraper ring comprises a lower scraper ring 23, which is implemented according to the embodiment of fig. 5. First of all, according to the scraper ring of the present invention, two identical scraper rings are used in the scraper ring, which have two identical scraper ring profiles. Upper scraper ring 24 and lower scraper ring 26 are pressed radially outward toward cylinder inner surface 38 by expansion springs 34, which are embodied as MF bending springs. MF flex spring 34 maintains the defined axial distance between upper blade ring 24 and lower blade ring 26. In fig. 6, the oil scraper ring moves upward in the axial direction indicated by arrow AA.

The upper scraper ring 24 creates an "oil-collecting effect" due to the partially conical working surface 16, wherein the upper scraper ring 24 floats on the oil and the oil passes between the scraper rings 24, 26. Due to the transition area, the upper scraper ring 24 prevents oil from accumulating in front of the scraper ring and at the top between the upper scraper ring side 6 and the upper piston ring groove side. The scraper ring at the bottom has a symmetrical spherical running surface, which prevents the oil O from leaving the middle space of the ring downwards.

In this embodiment, oil is continuously delivered between upper scraper ring 24 and lower scraper ring 26 and through the MF expansion spring, which will prevent any coking of the spring.

Fig. 7 shows the three-component oil scraper ring as shown in fig. 6, which is moved in an axial direction downwards, as indicated by arrow AA.

Because the upper scraper ring 24 does not float on the oil film due to the running surface 16, the upper scraper ring creates a thin oil film and pushes most of the oil O forward of it. The upper blade ring has a greater scraping force than the lower blade ring 26 due to the different thickness of the oil layer. The difference in scraping force between the upper scraper ring and the lower scraper ring in the direction of the groove base (not shown) results therefrom.

In principle, in a three-component scraper ring, an upper scraper ring and a lower scraper ring with symmetrical spherical running surfaces are used. As a result of this arrangement, the lubricating oil is collected on the cylinder running surface in the upward stroke, and is collected due to the "oil collecting action" between the upper oil scraper ring and the lower oil scraper ring, and flows out toward the base of the piston ring groove. The scraped oil can be returned to the crankcase through a corresponding passage in the piston. This principle is based on the scraping force of the upper scraper ring 24, which is higher than the scraping force of the lower scraper ring during the downward movement. This is achieved because more oil can be scraped from a thicker layer of oil. In this case, the scraping force of the upper scraper ring is preferably reduced below the scraping force of the lower scraper ring. The result of this is that even during the upward movement, the "rear" scraper ring will scrape more oil in the direction of movement. In general, during the upward movement AA as well as during the downward movement, oil is collected between the scraper rings 24, 26 and transported in the direction of the groove base and further into the crankcase.

Two scraper rings according to fig. 2 were used.

List of references:

2, a scraper ring;

4 a ring body;

6 upper or side surfaces;

8 underside or side surface;

10 ring inner surface;

12 an outer surface of the ring;

14 ring outer contour;

16 running surface;

18 pivot point of the radially outermost position or ring outer contour of the running surface;

20 radius of curvature R and the transition between the upper side;

22 a transition between the radius of curvature R and the underside;

24, mounting a scraper ring;

26 lower scraper ring;

28 three-component piston/scraper rings;

30 upper transition part tangent;

32 lower transition tangent;

34 spring/expansion spring;

36 MF spring/MF expansion spring;

38 a cylinder inner surface;

42 a conventional scraper ring;

44 piston upward direction of movement;

46 piston downward direction of motion;

axial direction A;

AA is moved upward in the axial direction;

AB moves downwards in the axial direction;

g is a straight line extending parallel to the axial direction;

the height of the H ring body;

o oil;

p height of the radially outermost position of the ring outer contour of the running surface;

r the radial extension of the outer surface of the ring;

r radius of curvature of running surface;

ro is connected to the radius of curvature of the upper flank;

ru curvature transition radius Ru;

radius of curvature of running surface of Rsdt traditional scraper ring;

t common tangent to radii of curvature R and Ro;

the angle of the alpha cone angle or common tangent in the axial direction.