Non-return valve

1. A non-return valve comprising:

a hollow sealing piston received in a valve housing and biased against a valve seat by means of a spring in a basic position, so that in the basic position a pressure medium connection between two working ports in a direction of flow therethrough is closed; and

wherein the sealing piston is manufactured by a plastics injection molding technique;

wherein the sealing piston includes a star configuration of bores, through the bores of which a pressure medium may flow into a spring chamber in an opened position; and

wherein guide projections are formed between the bores, which guide projections have a triangular shape and taper in a flow-receiving direction.

2. The non-return valve in accordance with claim 1 , wherein the sealing piston is manufactured of a plastics material PEEK.

3. The non-return valve in accordance with claim 1 , wherein the sealing piston is reinforced by 30% of carbon fiber.

4. The non-return valve in accordance with claim 1 , wherein the sealing piston includes a multiplicity of recesses on an outer periphery, so that the sealing piston is guided in a longitudinal bore by axial webs delimiting the recesses from each other.

5. The non-return valve in accordance with claim 4 , wherein six recesses and four bores are provided.

6. The non-return valve in accordance with claim 1 , wherein the sealing piston comprises a flow-receiving cone.

7. The non-return valve in accordance with claim 6 , wherein the flow-receiving cone has a rounded head.

8. A non-return valve comprising:

a hollow sealing piston received in a valve housing and biased against a valve seat by means of a spring in a basic position, so that in the basic position a pressure medium connection between two working ports in a direction of flow therethrough is closed; and

wherein the sealing piston is manufactured by a plastics injection molding technique;

wherein the sealing piston includes a star configuration of bores, through the bores of which a pressure medium may flow into a spring chamber in an opened position; and

wherein guide projections are formed between the bores, the guide projections having an axial length approximately corresponding to inner diameters of the bores; and

wherein the sealing piston is adapted for a flow therethrough and includes a multiplicity of recesses on an outer periphery, so that the sealing piston is guided in a longitudinal bore by axial webs delimiting the recesses from each other;

wherein the guide projections extend forward, to between the star configuration of bores, from an annular collar of the sealing piston; and

wherein the axial webs extend rearward from the annular collar.

9. The non-return valve in accordance with claim 8 , wherein the sealing piston is manufactured of a plastics material PEEK.

10. The non-return valve in accordance with claim 8 , wherein the sealing piston is reinforced by 30% of carbon fiber.

11. The non-return valve in accordance with claim 8 , wherein six recesses and four bores are provided.

12. The non-return valve in accordance with claim 8 , wherein the sealing piston comprises a flow-receiving cone.

13. The non-return valve in accordance with claim 12 , wherein the flow-receiving cone has a rounded head.

14. A non-return valve comprising:

a hollow sealing piston received in a valve housing and biased against a valve seat by means of a spring in a basic position, so that in the basic position a pressure medium connection between two working ports in a direction of flow therethrough is closed; and

wherein the sealing piston is manufactured by a plastics injection molding technique;

wherein the spring is supported in the valve housing by a spring cup made of plastics;

wherein the spring cup has at its outer periphery and/or on its front side at least one sealing lip;

wherein the spring cup further includes radial sealing lips that are inclined against a direction of pressure build-up; and

wherein front-side sealing lips are inclined in the direction of pressure build-up.

15. The non-return valve in accordance with claim 14 , wherein the sealing piston is manufactured of a plastics material PEEK.

16. The non-return valve in accordance with claim 14 , wherein the sealing piston is reinforced by 30% of carbon fiber.

17. The non-return valve in accordance with claim 14 , wherein the sealing piston includes a multiplicity of recesses on an outer periphery, so that the sealing piston is guided in a longitudinal bore by axial webs delimiting recesses from each other.

18. The non-return valve in accordance with claim 17 , wherein six recesses and four bores are provided.

19. The non-return valve in accordance with claim 14 , wherein the sealing piston comprises a flow-receiving cone.

20. The non-return valve in accordance with claim 19 , wherein the flow-receiving cone has a rounded head.