PISTON RING

Abstract

A piston ring has a ring body and a ring joint. The ring body has a first and a second ring body end which lie opposite each other and which define the ring joint. The first ring body end has a protruding section with a protrusion contour cross-section, and the second ring body end has a base section with a base section contour. A protruding section separating surface of the protruding section and a base section separating surface of the base section lie opposite each other so as to sealingly contact each other in a two-dimensional manner and define a separating plane. The separating plane has an inclination opposite that of a first axial ring surface. The separating plane defines an outer separating line and an inner separating line. At least one of the separating lines has a curvature radius which is concentric to the ring body.

Claims

1-7. (canceled)

8. A piston ring for a piston with an outer ring groove having an axial ring groove surface, the piston for disposition in a cylinder with a cylindrical inner barrel surface, the piston ring comprising: a ring body having a first ring body end and a second ring body end and a ring joint, said first and second ring body ends being arranged opposite one another for defining said ring joint; said ring body having a ring body surface including a radial ring surface being a sliding contact surface axially displaceable relative to the inner barrel surface and a first axial ring surface being a lay-on surface for resting on the axial ring groove surface; said first ring body end having a projection section with a projection section separating surface and a projection contour cross section; said second ring body end having a base section with a base section separating surface and a base section contour, said base section defining a receiving contour with a receiving contour cross section, said projection section engaging in said receiving contour, and said receiving contour cross section and said projection section cross section coincide; said projection section separating surface and said base section separating surface being provided opposite one other in an areal and sealing physical contact and defining a separating plane; said separating plane having an inverse inclination with respect to said inclined ring surface, said separating plane intersecting said radial ring surface and defining an outer separating line at an intersection line of said separating plane with said radial ring surface, said separating plane intersecting said first axial ring surface and defining an inner separating line at a second intersection line of said separating plane with said first axial ring surface, said separating lines defining said separating surfaces, and at least one of said separating lines having a curvature radius concentric with said ring body.

9. The piston ring according to claim 8, wherein said outer separating line and said inner separating line have a curvature radius concentric with said ring body and with one other.

10. The piston ring according to claim 8, wherein said separating surfaces are constructed as lateral truncated-cone sub-surfaces.

11. The piston ring according to claim 8, wherein said receiving contour cross section is a triangle.

12. The piston ring according to claim 8, wherein said separating surfaces are constructed as wire erosion surfaces.

13. The piston ring according to claim 8, wherein said ring body has at least one weakening recess arranged radially on the inside.

14. A piston ring arrangement, comprising: a first piston ring and a second piston ring, said piston rings are constructed according to claim 8; said piston rings each having a respective second axial ring surface, and said piston rings being arranged in parallel, said second axial ring surface of said first piston ring and said second axial ring surface of said second piston ring resting in physical contact against each other.

Description

[0048] By using an exemplary embodiment, the invention is explained in more detail below on the basis of the attached drawings. They show:

[0049] FIG. 1 Top view of a piston ring

[0050] FIG. 2 Cross sectional view of a piston ring

[0051] FIG. 3 Detailed section of a piston ring at the ring body ends in an oblique view

[0052] FIG. 4 Sectional view and schematic representation of the ring body ends

[0053] FIG. 5 Top view of a piston ring with weakening recesses

[0054] FIG. 6 Cross sectional view of a piston ring arrangement.

[0055] FIG. 1 shows the piston ring in a top view along the main longitudinal axis, which corresponds to the movement axis of the piston. The figure depicts the ring body 1 with the ring body surface 2, which comprises the radial ring surface 3 and the first axial ring surface 5. The ring body 1 is interrupted at one point. Here, a first ring body end 7 and a second ring body end 8 are opposite each other. The interruption between them is the ring joint 9.

[0056] The ring is shown in the unassembled, relaxed production position, also referred to as the relaxation position. In this embodiment, the ring body ends 7, 8 do not project one above the other in the relaxation position. In an alternative design—not shown here—a partial projection into the respective other ring body end 7, 8 already exists in the relaxation position.

[0057] In FIG. 1, an arc is also drawn over the inner separating line 20 with a radius arrow to show the concentric formation of the inner separating line 20, which is essential for the invention.

[0058] FIG. 2 shows the cross section of the ring body 1 through the ring joint 9. The ring body surface 2 designates the surface of the complete piston ring. The outer barrel surface of the ring body 1 is the radial ring surface 3. On one of the two sides of the ring body 1 is the first axial ring surface 5. The second axial ring surface 26 is provided opposite to it. By means of this surface the piston ring engages in the matching counter contour of a circumferential ring groove of a piston. Furthermore, the figure shows the projection section 10 with the projection contour cross section 11—highlighted by the dashed circular line—as well as the projection section separating surface 16. The inner separating line 20 is located on the first axial ring surface 5 and the outer separating line 19 is located on the radial ring surface 3, and both are concentric to each other and to the ring body 1 as a whole.

[0059] FIG. 3 shows the section of the piston ring at the ring joint 9 and at the ring body ends 7, 8 in an oblique view.

[0060] In this view, the non-installed shape of the piston ring is illustrated in the relaxation position. It shows the outside of the piston ring in the direction of the radial ring surface 3. The first axial ring surface 5 is located circumferentially at an angle of inclination to this. The projection section 10 is located at the first ring body end 7 and comprises the projection section separating surface 16 opposite to the view direction of FIG. 3.

[0061] The corresponding counterpart at the second ring body end 8 is the base section 12. The receiving contour 14 is defined by the separating plane 18; it forms the base section separating surface and receives the projection section 10 in an areal manner. In the tensioned installation position, the projection section 10 with the projection section separating surface 16 lies flat on the base section 12, i.e., on the base section separating surface 17. The separating plane 18 is formed there. The piston ring interrupted at the ring joint 9 is sealed again by the areal contact of the projection section separating surface 16 and the base section separating surface 17 in the separating plane 18.

[0062] In the overlap zone of the projection section separating surface 16 and the base section separating surface 17, the separating plane 18 has the shape of a section of a truncated-cone surface in this exemplary embodiment. The inner separating line 20 is formed at the curved edge to the first axial ring surface 5 and the outer separating line 19 is formed at the curved edge to the radial ring surface 3. The separating lines 19, 20 describe circular arcs which are arranged concentrically to the circle center point of the ring body, which enables a congruent sliding of the projection section separating surface 16 and the base section separating surface 17 on top of each other during a circumferential expansion or circumferential reduction of the piston ring.

[0063] FIG. 4 is a schematic representation of the piston ring in the installed condition. The individual gaps between the various components are greatly enlarged for a better view and are not true to scale. FIG. 4 as a schematic diagram is intended to illustrate the positional and movement relationships of the components as well as the acting forces.

[0064] Thus, according to FIG. 4, the ring body 1 is installed in a ring groove 6 of a piston 21. The ring groove 6 comprises an axial ring groove surface 23. When the piston moves in the cylinder, the piston ring slides axially off the inner barrel surface 4 of the cylinder 22 with its radial ring surface 3. The pressure medium acts with the pressure p on the second axial ring surface of the piston ring. The piston ring is pressed in the ring groove 6 of the piston 21 against the axial ring groove surface 23 and slides in a floating manner thereon with its first axial ring surface 5. At the same time, the pressure medium acts in the area of the groove base of the ring groove 6 against the radial inner ring surface of the piston ring (no reference numeral) and, depending on the pressure, ensures that the radial ring surface 3 is pressed against the inner barrel surface 4 of the cylinder 22, which leads to an increased sealing effect at this sliding contact surface. In addition, the projection contour cross section 11 can slide off with the projection section separating surface 16 on the base section separating surface 17 of the base section contour 13 along the separating plane 18 both transversely—as shown by the double arrow between the separating surfaces 16, 17— and longitudinally, i.e., along the circumference. At the same time, the projection section 10 and the base section 12 are axially displaceable with respect to each other along the radial ring surface 3 and the inner barrel surface 4 so that the gap between the separating surfaces 16, 17 can always be closed again, even in the case of wear.

[0065] This sliding-off of the separating surfaces 16, 17 transversely and longitudinally in conjunction with the axial displaceability of the sections 10, 12 enables compensation for material abrasion on the piston ring due to wear and always ensures areal contact and thus a constant sealing effect during the service life.

[0066] FIG. 5 depicts a piston ring in which weakening recesses 28 are arranged opposite the radial ring surface 3. A total of seven weakening recesses 28, which are arranged at an angle of 45 degrees to each other, are provided in the exemplary embodiment. Furthermore, the weakening recesses 28 adjacent to the ring joint 9 each include an angle of likewise 45 degrees with respect to the ring joint 9. Due to the weakening recesses 28 and due to their uniform distribution, the spring-force-induced contact forces against an inner barrel surface 4 of a cylinder are reduced around the circumference in a uniformly-distributed manner, and the free movability and self-adjusting action between the projection section and the base section are supported. And, at the same time, the advantageous contact forces caused by the operating pressure of a pressure medium remain unimpaired.

[0067] FIG. 6 shows a piston ring arrangement comprising a first piston ring 24 and a second piston ring 25. Both piston rings 24, 25 are designed as piston rings according to the invention. In addition, they each have a second axial ring surface 26, 27. The two piston rings 24, 25 lie against each other at the axial ring surfaces 26, 27, wherein in this manner they are mounted in floating position relative to each other.

REFERENCE NUMERALS

[0068] 1 ring body [0069] 2 ring body surface [0070] 3 radial ring surface [0071] 5 inner barrel surface [0072] 5 first axial ring surface [0073] 6 outer ring groove of a piston [0074] 7 first ring body end [0075] 8 second ring body end [0076] 9 ring joint [0077] 10 projection section [0078] 11 projection contour cross section [0079] 12 base section [0080] 13 base section contour [0081] 14 receiving contour [0082] 15 receiving contour cross section [0083] 16 projection section separating surface [0084] 17 base section separating surface [0085] 18 separating plane [0086] 19 outer separating line [0087] 20 inner separating line [0088] 21 piston [0089] 22 cylinder [0090] 23 axial ring groove surface [0091] 24 first piston ring [0092] 25 second piston ring [0093] 26 second axial ring surface of the first piston ring [0094] 27 second axial ring surface of the second piston ring [0095] 28 weakening recess