DE8503197U1 - Piston ring - Google Patents

Description

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Piston ring. The innovation relates to a piston ring, in particular

co-operating spring, tensioning radially outwards
and whose outer circumferential surface forms the running surface

has denden, circumferential central web. |

The German utility model 1 725 135 is ready}

a generic piston ring with a central web is known, '',

the closed with a band spring tensioning radially outward ^;

interacts over the entire axial height ί

of the piston ring extends. i

Furthermore, the DE - OS 21 17 412, a piston ring _analogue: Type of construction, which, however, radially outwards itself- '·

exciting, i.e. designed without a spring. ■, -

A disadvantage is to be noted here that piston rings with Ribbon springs have a relatively hard spring characteristic, the I.

leads to the fact that the oil scraping effect, based on the a

Running time, wears off relatively quickly. Also with |

Reduction in the overall axial height of both the piston ring and the spring, the disadvantages remain. From it
results in the task of having a two-piece piston ring
to design optimized axial height, the same

early has a soft spring rate. \

This object is achieved according to the invention in that the ;;

The spring is an annularly curved helical compression spring which is guided in a spring retaining groove in the piston rings. The ratio of the radial wall thickness of the piston ring to its overall height is greater than 1.1. The advantages over the prior art are essentially to be seen in the fact that the innovation enables a piston ring to be realized which has a maximum overall height of 2 mm. In addition, the helical compression spring has a soft spring characteristic and is guided on the same side in the spring retaining groove, ie, in contrast to a ribbon or meander spring, it cannot move in the axial direction. The secondary wear that occurs between the spring and the piston ring during operation is thus also reduced to a minimum. The KoI-benring can be made of cast iron or it is wound from a suitably profiled steel strip. Another advantage of the center leg ring compared to a conventional hose spring washer with two wiper edges is that, with the same surface pressure, the rubbing surface is only half as large. This results in a reduced friction loss. The choice of the ratio of the radial wall thickness to the axial overall height (greater than 1.1) also optimizes the cross-section of the piston ring. The radial wall thickness can be chosen so that on the one hand the flank wear of the ring remains within normal limits and on the other hand the flexibility of the ring, ie its adaptability to the contour of the cylinder, is sufficiently large. The ratio should not exceed 2.5 or only marginally so that the adaptability to the

Cylinder is not designed disadvantageously.

The specified construction height of a maximum of 2 mm is of course here from the nominal diameter of the piston rings · initially once independent. However, useful areas of application are in the diameter range from 45 to 100 mm.

According to a further idea of the innovation, the winding ratio of the helical compression spring is less than 2.0. That The winding behavior depends on the mean winding diameter and the wire cross-section. Only by choosing a winding ratio of less than 2.0 is it possible to to design a helical compression spring, which has a diameter of about 1.5 mm, which is in a corresponding The spring retaining groove of the approximately 2.0 mm high piston ring is guided.

Another advantageous development of the concept of innovation can be seen in the fact that the ratio of the distance between the running surface (outer diameter) / spring groove base to the Winding diameter is between 1.2 and 2.1. Even This selection enables the piston ring to be optimally adapted to the cylinder wall, if necessary simultaneous reduction of the groove depth of the piston ring

25 nut.

There is also the possibility of designing the catwalk in such a way that it increases from the outside to the inside Adjusts cross-section. The catwalk can initially run in a straight line and then continuously in direction

of the two end faces of the piston ring rise. Here there is an oil collecting chamber axially below the piston ring educated. The drainage of the oil into the oil sump should here through oil drainage bores, half of which are in the groove bottom of the piston ring groove and half in the groove bottom flank of the piston ring are introduced.

Alternatively, there is the possibility of designing the cross-section of the catwalk so that it is equal to the Starting from the running surface increases continuously in the direction of the two end faces. This measure makes sense in the event that the ring on its running surface with a Wear protection layer is to be provided.

The innovation is shown in the drawing and is described in more detail below. Show it:

Figures 1 and 2 axially low piston rings with different structural designs.

20th

In Figure 1, an oil control ring is shown, which is on The inner circumference of the ring 1 has a spring retaining groove 2 in which a helical compression spring 3 bent in a ring shape is guided is. The outer peripheral surface 4 of the ulabstreifringes has a central web 6 which forms the running surface 5 and which initially extends in a straight line radially from the outside to the inside 7 extends and then increases continuously in the direction of both end faces 8.9 10. The ratio of the radial wall thickness a to the axial construction height h should be, for example, 1.3, i.e., with an axial construction

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height h of 2.0 mm would be the radial wall thickness 2.6 mm. Qn to match the helical compression spring 3 to this overall height (2.0 mn), a winding ratio of around 1.5 must be selected, that depends on the mean coil diameter and the wire cross-section. As a further requirement for optimization of the ring cross-section is the ratio of the distance between the running surface 5 / spring groove base 11 and the coil diameter d of the helical compression spring 3 is selected with 1.3.

Figure 2 shows an oil control ring, which is axially even lower builds than the oil control ring shown in Figure 1. The catwalk 12 of the ring increases, starting out from the running surface S continuously in the direction of the two end faces 8.9. This is necessary in order to Applying the wear protection layer 13 a good Achieve build-up of the layer. The spring retaining groove 2 is only so slightly rounded here that the helical compression spring washer 3 is performed adequately. With measure IXBt you can achieve an axial construction height that is only slightly above the diameter (1.5 mn) of the spring 3 lie.

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Claims (20)

1. Piston ring, in particular oil control ring, which with a bearing on the ring circumference, radially after externally tensioning spring cooperates and the outer circumferential surface of which forms the running surface, having a circumferential central web, characterized in that the spring (3) is an annularly curved Helical compression spring which is guided in a spring retaining groove (2) of the piston ring, and that the ratio of the radial wall thickness (a) of the piston ring to its axial height (h) is greater than 1.1. 2. Piston ring according to claim 1, characterized in that the ratio of the radial wall thickness (a) drs Piston ring to its axial height (h) is a maximum of 2.5. 3. Piston ring according to claims 1 and 2, characterized in that that the axial height (h) of the piston ring is less than or equal to 2.0 mm. 4. Piston ring according to claims 1 to 3, characterized in that that the winding ratio of the helical compression spring (3) is less than 2.0. 5. Piston ring according to claims 1 to 4, characterized in that that the ratio of the distance running surface (5) / keyway base (11) to the coil diameter (d) the helical compression spring (3) is between 1.2 and 2.1. I 5 6. Piston ring according to claims 1 to 5, characterized by ^Ά indicates that the catwalk (6) has one from the outside . inwardly increasing cross-section, derg «* - J etalt that it initially runs in a straight line (7) and f then continuously in the direction of the two forehead <| 10 surfaces (8,9) of the piston ring increases (10). L 7. piston ring according to claims 1 to 5, characterized 4 indicates that the catwalk (12) is one from the outside f has an inwardly increasing cross-section, which * "15 etalt that he is continuously from the running surface (5) ν in the direction of the two end faces (8,9) of the col benringes increases. j 8. Piston ring according to claim 7, characterized in that 20 that the catwalk (12) with a wear protection layer (13) is coated.