PISTON RING

Abstract

A piston ring includes a ring body that has a first ring body end and a second ring body end and a ring joint. The first and second ring body ends are arranged opposite one another to define the ring joint. The ring body has a radial ring surface as a sliding contact surface axially displaceable relative to an inner barrel surface and an inclined ring surface that rests on an inclined ring groove surface. The first ring body end has a projection section with a projection section separating surface. The second ring body end has a base section with a base section separating surface and a base section contour. The base section defines a receiving contour. The projection section engages in the receiving contour, and a receiving contour cross section and a projection contour cross section coincide. The projection section separating surface and the base section separating surface are opposite one other in an areal and sealing physical contact and define a plane that has an inverse inclination with respect to the inclined ring surface. The plane intersects the radial ring surface and defines an outer separating line at an intersection line of the plane with the radial ring surface. The plane intersects the inclined ring surface and defines an inner separating line at a second intersection line of the plane with the inclined ring surface. The separating lines define the separating surfaces, and at least one of the separating lines has a curvature radius concentric with the body.

Claims

1-9. (canceled)

10. A piston ring for a piston with an outer ring groove having an inclined 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 cylindrical inner barrel surface and an inclined ring surface being a lay-on surface for resting on the inclined 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 contour 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 inclined ring surface and defining an inner separating line at a second intersection line of said separating plane with said inclined 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.

11. The piston ring according to claim 10, wherein said outer separating line and said inner separating line have a curvature radius concentric with said ring body and with one other.

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

13. The piston ring according to claim 10, wherein said receiving contour cross section is a triangle.

14. The piston ring according to claim 10, wherein said separating surfaces are constructed as wire erosion surfaces.

15. The piston ring according to claim 10, wherein said ring body has a further inclined ring surface, said further inclined ring surface is inclined inversely to said inclined ring surface.

16. The piston ring according to claim 15, wherein: said first ring body end has a further projection section with a further projection contour cross section; said base section has a further receiving contour with a further receiving contour cross section; said further projection section engages in said further receiving contour and said further receiving contour cross section and said further projection contour cross section coincide; a further projection section separating surface of said further projection section and a further base section separating surface of said base section are opposite to each other in an areal and sealing physical contact and defines a further separating plane; said further separating plane has an inverse inclination to said further inclined ring surface; said further separating plane intersects said radial ring surface and defines a further outer separating line at an intersection line of said further separating plane with said radial ring surface; said further separating plane intersects said further inclined ring surface and defines a further inner separating line at an intersection line of said further separating plane with said further inclined ring surface; said further separating lines define said further separating surfaces; and said further separating lines have a curvature radius concentric to one another and to said ring body.

17. The piston ring according to claim 10, wherein said ring body has at least one weakening recess arranged radially on the inside.

18. A piston ring arrangement, comprising: a first piston ring and a second piston ring, said piston rings are constructed according to claim 10; said piston rings each having a respective axial ring surface, and said piston rings being arranged in parallel, said axial ring surface of said first piston ring and said axial ring surface of said second piston ring resting in physical contact against each other.

Description

[0052] FIG. 1 Oblique view of a piston ring

[0053] FIG. 2 Top view of a piston ring

[0054] FIG. 3 Cross sectional view of a piston ring

[0055] FIG. 4 Detailed section of a piston ring at the ring body ends in an oblique view

[0056] FIG. 5 Sectional view and schematic representation of the ring body ends

[0057] FIG. 6 Cross sectional view of a piston ring with two inclined ring surfaces

[0058] FIG. 7 Cross sectional view of a piston ring with two inclined ring surfaces and two projection sections

[0059] FIG. 8 Schematic view of a piston ring with two inclined ring surfaces and two projection sections

[0060] FIG. 9 Schematic view of the base section of a piston ring with two inclined ring surfaces and two projection sections

[0061] FIG. 10 Top view of a piston ring with weakening recesses

[0062] FIG. 11 Cross sectional view of a piston ring arrangement.

[0063] FIG. 1 shows the piston ring for a first overview in an oblique view; FIG. 2 shows the piston ring in a top view along the main longitudinal axis, which corresponds to the movement axis of the piston. Both FIGS. 1 and 2 show the ring body 1 with the ring body surface 2, which comprises the radial ring surface 3 and the inclined 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 situated opposite to each other. The interruption between them forms the ring joint 9.

[0064] 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.

[0065] FIG. 3 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 an axial side, the ring body 1 has the inclined ring surface 5 by means of which the piston ring engages in the matching counter contour of a circumferential ring groove of a piston. Furthermore, 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 are shown.

[0066] FIG. 4 shows the section of the piston ring at the ring joint 9 and at the ring body ends 7, 8 in an oblique view.

[0067] The non-installed shape of the piston ring in the relaxation position is illustrated in this view. It shows to the outside of the piston ring in the direction of the radial ring surface 3. The inclined 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 in FIG. 3.

[0068] The corresponding counterpart at the second ring body end 8 forms the base section 12. The receiving contour 14 is defined by the separating plane 18; it forms the separating surface of the base section 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.

[0069] 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 inclined 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, thus enabling 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.

[0070] FIG. 5 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. 5 as a schematic diagram is intended to illustrate the positional and movement relationships of the components and the forces acting on them.

[0071] Thus, according to FIG. 5, the ring body 1 is installed in a ring groove 6 of a piston 21. This groove is designed with an inclined ring groove surface 23. When the piston moves in the cylinder, the piston ring slides with the radial ring surface 3 axially off the inner barrel surface 4 of the cylinder 22. The pressure medium acts with the pressure p on the planar, axial ring surface of the piston ring (no reference numeral). The piston ring is pressed in the ring groove 6 of the piston 21 against the inclined ring groove surface 23 and slides thereon with its inclined ring surface 5. The inclination is designed such that it provides a sealing effect against the pressure medium and, at the same time, also causes a radial force on the piston ring due to the wedge effect and thus expands it. This in turn 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. 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 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 relative 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 case of wear.

[0072] 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.

[0073] FIG. 6 shows an embodiment in which the piston ring has a further inclined ring surface 23.

[0074] Primarily, the explanations to FIG. 2 apply in a corresponding manner. In addition, the further inclined ring surface 23 is provided here. In this embodiment, the ring surfaces 5, 23 are positioned symmetrically opposite to each other.

[0075] FIG. 7 and FIG. 8 show an embodiment in which the piston ring has, in addition to the further inclined ring surface 24, a further projection section 25 and a further projection contour 26. For better illustration, FIG. 7 shows schematically the symmetrical design in the exemplary embodiment, and also here, as in FIG. 4, the gaps between the various components are greatly enlarged for a better view and are not true to scale.

[0076] The inclined ring surface 5, the projection section separating surface 16 and, opposite thereto, the base section separating surface 17 of the base section 12 with the separating plane 18, formed in between and defined by the inner separating line 20 and the outer separating line 19, are allocated to the projection section 10.

[0077] The further inclined ring surface 24, the further projection section separating surface 29 and, opposite thereto, the further base section separating surface 30 of the base section 12 with the further separating surface 31, formed in between and defined by the further inner separating line 33 and the further outer separating line 32, are allocated to the further projection section 25.

[0078] FIG. 9 shows the base section 12 in a schematic sectional view in a radial sectional plane. FIG. 9 shows, in particular, the receiving contour 14 with its receiving contour cross section 11 as well as the further receiving contour 27 with its receiving contour cross section 28. In all other respects, the contents of the description for and reference numerals of FIG. 7 apply accordingly. In the installation space spanned by the further receiving contour 27, the further projection section 25 is arranged in a tensioned condition, as shown in FIG. 7. Accordingly, the projection section 10 is arranged in a tensioned position in the installation space spanned by the receiving contour 14, as also shown in FIG. 7.

[0079] FIG. 10 shows a piston ring in which weakening recesses 38 are arranged opposite the radial ring surface 3. A total of seven weakening recesses 38, which are arranged at an angle of 45 degrees to each other, are provided in the exemplary embodiment. Furthermore, the weakening recesses 38 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 38 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.

[0080] FIG. 11 shows a piston ring arrangement comprising a first piston ring 34 and a second piston ring 35. Both piston rings 34, 35 are designed as piston rings according to the invention. In addition, they each have an axial ring surface 36, 37. The two piston rings 34, 35 lie against each other at the axial ring surfaces 36, 37, wherein in this manner they are mounted in floating position relative to each other.

LIST OF REFERENCE NUMERALS

[0081] 1 ring body [0082] 2 ring body surface [0083] 3 radial ring surface [0084] 4 inner barrel surface [0085] 5 inclined ring surface [0086] 6 outer ring groove of a piston [0087] 7 first ring body end [0088] 8 second ring body end [0089] 9 ring joint [0090] 10 projection section [0091] 11 projection contour cross section [0092] 12 base section [0093] 13 base section contour [0094] 14 receiving contour [0095] 15 receiving contour cross section [0096] 16 projection section separating surface [0097] 17 base section separating surface [0098] 18 separating plane [0099] 19 outer separating line [0100] 20 inner separating line [0101] 21 piston [0102] 22 cylinder [0103] 23 inclined ring groove surface [0104] 24 further inclined ring surface [0105] 25 further projection section [0106] 26 further projection contour cross section [0107] 27 further receiving contour [0108] 28 further receiving contour cross section [0109] 29 further projection section separating surface [0110] 30 further base section separating surface [0111] 31 further separating plane [0112] 32 further outer separating line [0113] 33 further inner separating line [0114] 34 first piston ring [0115] 35 second piston ring [0116] 36 axial ring surface of the first piston ring [0117] 37 axial ring surface of the second piston ring [0118] 38 weakening recess