Magnet system
| Title: | Magnet system |
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| Patent Number: | 5,161,779 |
| Publication Date: | November 10, 1992 |
| Appl. No: | 07/702,539 |
| Application Filed: | May 20, 1991 |
| Abstract: | A magnet system for magnet valves for controlling liquids including an electromagnet and a permanent magnet that produces magnetic fluxes, the magnetic fluxes of which are oriented opposite one another in a working air gap formed between a free-floating armature and a magnet pole. To attain a course of the force of attraction acting upon the armature that becomes negative beyond a certain excitation of the electromagnet, and to reduce the trigger power for the electromagnet, a magnetic opposite pole is disposed on the side of the armature remote from the working air gap, forming a second working air gap, which is coupled to the magnet housing, optionally via a stray air gap, via a flow guide element annularly engaging the permanent magnet. |
| Inventors: | Graner, Juergen (Sershiem, DEX); Bantleon, Guenther (Salach, DEX); Kubach, Hans (Hemmingen, DEX); Kirchner, Marcel (Stuttgart, DEX) |
| Assignees: | Robert Bosch GmbH (Stuttgart, DEX) |
| Claim: | What is claimed and desired to be secured by Letters Patent of the United States is |
| Claim: | 1. A magnet system for magnet valves for controlling liquids, in particular for fuel injection valves, having an electromagnet, which has a magnet core forming a magnet pole, an exciter coil surrounding the magnet core and a magnet housing coaxial with and surrounding the exciter coil, said housing forms a magnetic short circuit and is connected via a short-circuit yoke to a face end of the magnet core remote from a pole face, an annular permanent magnet with an axial direction of magnetization, the permanent magnet being disposed coaxially with the magnet core near its pole face, and having an approximately disk-shaped armature, which is located free-floatingly opposite the magnet pole, forming a working air gap with the pole face thereof, wherein a circulation of the exciter coil and the disposition of the permanent magnet are selected such that the magnetic fluxes of the electromagnet and permanent magnet are in opposite directions to one another in the working air gap, a magnetic opposite pole (29) disposed on a side of the armature (28) remote from the working air gap (31), said magnetic opposite pole (29) forms a second working air gap (32) between its pole face (30) and the armature (28), said magnetic opposite pole is coupled to the magnet housing (25) via a magnetic flux guiding pole plate (35) which is spaced circumferentially from the permanent magnet (21). |
| Claim: | 2. A magnet system as defined by claim 1, in which the coupling of the magnetic opposite pole (29) to the magnet housing (25) by the pole plate (35) is performed via a stray air gap (34). |
| Claim: | 3. A magnet system as defined by claim 1, in which the end face of the magnet housing (25) remote from the short-circuit yoke (26) is connected to the magnet core (24), near its pole face (23), via a preferably integral annular land (27); that the permanent magnet (21) rests on the annular land (27); and that the annular land (27) has a magnetic constriction (40) acting in the radial direction. |
| Claim: | 4. A magnet system as defined by claim 2, in which the end face of the magnet housing (25) remote from the short-circuit yoke (26) is connected to the magnet core (24), near its pole face (23), via a preferably integral annular land (27); that the permanent magnet (21) rests on the annular land (27); and that the annular land (27) has a magnetic constriction (40) acting in the radial direction. |
| Claim: | 5. A magnet system as defined by claim 3, in which the magnetic constriction (40) is embodied such that it is magnetically saturated, or attains this saturation state very quickly upon application of an electric exciter current to the exciter coil (38). |
| Claim: | 6. A magnet system as defined by claim 4, in which the magnetic constriction (40) is embodied such that it is magnetically saturated, or attains this saturation state very quickly upon application of an electric exciter current to the exciter coil (38). |
| Claim: | 7. A magnet system as defined by claim 3, in which the magnet constriction (40) is achieved by means of an annular groove (39) provided in the annular land (27). |
| Claim: | 8. A magnet system as defined by claim 4, in which the magnet constriction (40) is achieved by means of an annular groove (39) provided in the annular land (27). |
| Claim: | 9. A magnet system as defined by claim 5, in which the magnet constriction (40) is achieved by means of an annular groove (39) provided in the annular land (27). |
| Claim: | 10. A magnet system as defined by claim 6, in which the magnet constriction (40) is achieved by means of an annular groove (39) provided in the annular land (27). |
| Claim: | 11. A magnet system as defined by claim 3, in which the magnetic opposite pole (29) with the pole plate is embodied as an integral pole plate (35), which annularly surrounds the permanent magnet (21) with radial spacing and is magnetically coupled to the annular land (27) and/or magnet housing (25). |
| Claim: | 12. A magnet system as defined by claim 5, in which the magnetic opposite pole (29) with the pole plate is embodied as an integral pole plate (35), which annularly surrounds the permanent magnet (21) with radial spacing and is magnetically coupled to the annular land (27) and/or magnet housing (25). |
| Claim: | 13. A magnet system as defined by claim 7, in which the magnetic opposite pole (29) with the pole plate is embodied as an integral pole plate (35), which annularly surrounds the permanent magnet (21) with radial spacing and is magnetically coupled to the annular land (27) and/or magnet housing (25). |
| Claim: | 14. A magnet system as defined by claim 11, in which between the pole plate (35) and the annular land (27) or magnet housing (25), a stray air gap (34) is formed, which is magnetically biased by means of a magnetic flux which is tapped at the permanent magnet (21), in its region (67) protruding beyond the armature (28). |
| Claim: | 15. A magnet system as defined by claim 12, in which between the pole plate (35) and the annular land (27) or magnet housing (25), a stray air gap (34) is formed, which is magnetically biased by means of a magnetic flux which is tapped at the permanent magnet (21), in its region (67) protruding beyond the armature (28). |
| Claim: | 16. A magnet system as defined by claim 13, in which between the pole plate (35) and the annular land (27) or magnet housing (25), a stray air gap (34) is formed, which is magnetically biased by means of a magnetic flux which is tapped at the permanent magnet (21), in its region (67) protruding beyond the armature (28). |
| Claim: | 17. A magnet system as defined by claim 11, in which the pole plate (35) has a concentric through opening (47) for a valve member (48) for the magnet valve, which member is firmly joined to the armature (28). |
| Claim: | 18. A magnet system as defined by claim 14, in which the pole plate (35) has a concentric through opening (47) for a valve member (48) for the magnet valve, which member is firmly joined to the armature (28). |
| Claim: | 19. A magnet system as defined by claim 11, in which the pole plate (35) is secured to the magnet housing (25) via a holder (37), and that the holder (37) is of nonmagnetic material or of soft magnetic material having a Curie temperature of 80.degree. C., such as iron-nickel. |
| Claim: | 20. A magnet system as defined by claim 14, in which the pole plate (35) is secured to the magnet housing (25) via a holder (37), and that the holder (37) is of nonmagnetic material or of soft magnetic material having a Curie temperature of 80.degree. C., such as iron-nickel. |
| Claim: | 21. A magnet system as defined by claim 17, in which the pole plate (35) is secured to the magnet housing (25) via a holder (37), and that the holder (37) is of nonmagnetic material or of soft magnetic material having a Curie temperature of 80.degree. C., such as iron-nickel. |
| Claim: | 22. A magnet system as defined by claim 1, in which the annular cross-sectional area of the permanent magnet located parallel to the pole face (23) of the magnet pole (22) facing the armature (28) is approximately 1.5 times larger than the sum of the pole faces (23, 30) of the magnet pole (22) and the opposite pole (29). |
| Claim: | 23. A magnet system as defined by claim 2, in which the annular cross-sectional area of the permanent magnet located parallel to the pole face (23) of the magnet pole (22) facing the armature (28) is approximately 1.5 times larger than the sum of the pole faces (23, 30) of the magnet pole (22) and the opposite pole (29). |
| Claim: | 24. A magnet system as defined by claim 3, in which the annular cross-sectional area of the permanent magnet located parallel to the pole face (23) of the magnet pole (22) facing the armature (28) is approximately 1.5 times larger than the sum of the pole faces (23, 30) of the magnet pole (22) and the opposite pole (29). |
| Claim: | 25. A magnet system as defined by claim 1, in which the permanent magnet (21) is made from iron-neodymium. |
| Claim: | 26. A magnet system as defined by claim 2, in which the permanent magnet (21) is made from iron-neodymium. |
| Claim: | 27. A magnet system as defined by claim 3, in which the permanent magnet (21) is made from iron-neodymium. |
| Claim: | 28. A magnet system as defined by claim 1, in which the armature (28) at least partially overlaps the permanent magnet (21), forming an annular gap (33), and the permanent magnet (21) is set back far enough with respect to the pole face (23) of the magnet pole (22) that with a minimum working air gap (31) between the armature (28) and the pole face (23) of the magnet pole (22), the annular air gap (33) between the armature (28) and the permanent magnet (21) is equivalent to the maximum stroke of the armature (28). |
| Claim: | 29. A magnet system as defined by claim 2, in which the armature (28) at least partially fits over the permanent magnet (21), forming an annular gap (33), and the permanent magnet (21) is set back far enough with respect to the pole face (23) of the magnet pole (22) that with a minimum working air gap (31) between the armature (28) and the pole face (23) of the magnet pole (22), the annular air gap (33) between the armature (28) and the permanent magnet (21) is equivalent to the maximum stroke of the armature (28). |
| Claim: | 30. A magnet system as defined by claim 3, in which the armature (28) at least partially overlaps the permanent magnet (21), forming an annular gap (33), and the permanent magnet (21) is set back far enough with respect to the pole face (23) of the magnet pole (22) that with a minimum working air gap (31) between the armature (28) and the pole face (23) of the magnet pole (22), the annular air gap (33) between the armature (28) and the permanent magnet (21) is equivalent to the maximum stroke of the armature (28). |
| Current U.S. Class: | 25112/916; 251/65; 25112/915; 25112/922 |
| Current International Class: | F16K 3106 |
| Patent References Cited: | 4403765 September 1983 Fisher 4890815 January 1990 Hascher-Reichl et al. |
| Primary Examiner: | Rosenthal, Arnold |
| Attorney, Agent or Firm: | Greigg, Edwin E. Greigg, Ronald E. |
| Accession Number: | edspgr.05161779 |
| Database: | USPTO Patent Grants |
| Language: | English |
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