Valve with check valve

1. A hydraulic valve, comprising:

a central guide having unsymmetrically distributed through-openings;

a check valve, the check valve comprising a band which is shaped into a closed ring with overlapping free ends, said closed ring being mounted in a freely floating rotatable manner on an inner surface of the central guide; and

a pressure connection (P) having an external encircling connection groove located on an outside of a section of the central guide;

wherein:

the closed ring is a band which is free from openings and, on the section of the central guide, closes the unsymmetrically distributed through-openings to the central guide in the event of blowback pressure differences;

the ring is mounted in a manner free from locking in an encircling internal double-stepped groove of the section of the central guide, and

the double-stepped groove is located beneath the encircling connection groove of the pressure connection (P) and comprises a deep groove and a shallow groove.

2. Valve as claimed in claim 1 , wherein:

the through-openings are bores which are uniformly spaced from one through-opening to the next through-opening within a portion of the section, and

over the entire section the through-openings are arranged in such a way that they are distributed unsymmetrically in the section.

3. Valve as claimed in claim 1 , wherein the valve is a tappet-operated cartridge valve with two working connections (A, B), the pressure connection (P) and a tank connection (T), the working connections (A, B) being optionally alternately connectable to the pressure connection (P).

4. Valve as claimed in claim 1 , wherein the overlapping closed ring is produced from a spring steel, which forms the ring by an overlap of a substantial portion of the band.

5. Valve as claimed in claim 3 , wherein the working connections (A, B) are furnished with openings to the central guide which are also unsymmetrically distributed uniformly over the entire circumference.

6. Valve as claimed in claim 3 , wherein the working regions (A, B) are furnished with regions which have openings to the central guide, and are furnished with regions which are designed free from openings.

7. Valve as claimed in claim 1 , further wherein a diameter of the through-openings are in a ratio below 0.5 of a width of the band.

8. Valve as claimed in claim 1 , wherein the section comprises a circular-arc section of 240°.

9. Valve as claimed in claim 4 , wherein the overlap covers at least 90° of the ring and not more than 270° of the ring.

10. Valve as claimed in claim 9 , wherein the overlap covers approximately 180° of the ring.

11. Valve as claimed in claim 1 , wherein the deep groove having a smaller width than the shallow groove.

12. Valve as claimed in claim 7 , wherein the diameter of the through-openings are in a ratio between 0.4 and 0.5 of a width of the band.

13. Valve as claimed in claim 11 , wherein the shallow groove spreads out towards the deep groove.

14. A hydraulic valve, comprising:

a central guide having unsymmetrically distributed through-openings;

a check valve, the check valve comprising a band which is shaped into a closed ring with overlapping free ends, said closed ring being mounted in a freely floating rotatable manner on an inner surface of the central guide; and

a pressure connection (P) having an external encircling connection groove located on an outside of a section of the central guide;

wherein:

the closed ring is a band which is free from openings and, on the section of the central guide, closes the unsymmetrically distributed through-openings to the central guide in the event of blowback pressure differences;

the ends of the closed ring are free from burrs; and

the ends of the closed ring have an irregular shape.

15. Valve as claimed in claim 14 , wherein the ring is present on the inner surface of the central guide beneath the pressure connection (P).