SOLENOID VALVE

Abstract: Solenoid valve (1) comprising a coil (2) surrounding a guide (3) for an armature (4), the armature (4) being movable in the guide (3) through magnetising of the coil (2) or by means of a return mechanism (5), and a valve seat (6) co-operating with a closing member (7) for selective opening or closing of a valve opening (8) through the valve seat (6) controlled by the armature (4) movement. As the closing member (7) is a separate device in relation to the armature (4), which closing member is activated by the armature (4) movement to a rocking movement around a contact point with the valve seat (6), an N.O. or N.C. solenoid valve of a simplified construction is obtained.

Description: Solenoid valve The invention concerns a solenoid valve of the kind mentioned in the preamble of claim 1. In such solenoid valves the closing member is normally integrated in the armature, being a sealing surface inserted in the armature, which, by means of an armature return spring, at currentless (non-magnetised) coil is brought to sealingly bearing against the valve seat, and at magnetised coil is pulled away from the valve seat to permit medium flow through the valve opening. Such a solenoid valve, in which the medium flow is interrupted at currentless coil, is called a normally closed (N.C.) valve. In certain applications it would be advantageous to use a normally open (N.O.) valve, whose construction, however, is usually of a much more complicated nature. The most frequently used medium flow direction in normal valves of the embodiment described above is into the valve housing, past the closing member and out through the valve opening in the valve seat. This gives a secure closing function, the increasing differential pressure acting upon the closing member to pressing harder against the valve seat. If, however, the flow direction is reversed, it is achieved that if the differential pressure exceeds a certain value, which is determined by the valve opening area and the force influence of the return mechanism, the pressure will move the closing member away from the valve seat and let the medium flow through the valve. In certain cases this function can be desirable as security valve function, but the pressure at which the valve opens is substantially determined in advance by the dimensioning requirements for return mechanism and valve opening determined by the sole- noid valve function. On the basis of this state of the art, it is the purpose of the present invention to produce a simplified construction of an N.O. solenoid valve. According to the invention this is obtained by the measures stated in the characterising part of claim 1. Making the closing member as a separate part in relation to the armature, which member is activated by the armature movement to a rocking movement around a contact point with the valve seat, enables an inversion of the armature movement so that the valve becomes an N.O. valve. However, the force transfer between armature and closing member can also be made without this inversion, so that the valve is an N.C. valve (see fig. 9). Preferred embodiments of valve seat and closing member for production of rolling and/or sliding rocking movements of the closing member on a surface surrounding the valve seat appear from the claims 2 to 5. Preferred embodiments and arrangements of a closing spring for the closing member acting upon the closing member to perform a tight closing against the valve seat appear from the claims 6 to 8. The closing spring can be arranged between the armature and the closing member or, as stated in claims 7 to 8, pass through a bore in the armature and rest against the bottom of the armature guide. Preferably, as stated in claims 9 and 10, the rocking movement is produced by means of a projecting edge on the armature or the closing member, respectively, which edge makes the armature act upon the closing member offset in relation to the valve seat centre outside the valve seat diameter. The offset action can also, as stated in claim 11, be produced or supplemented, respectively, by an asymmetrical arrangement of the armature in relation to the closing member. When using the solenoid valve comprising a closing spring for urging of the closing member against the valve seat in an application, in which the medium flows in via the valve seat, the security function mentioned above is obtained, the construction according to the present invention giving an additional degree of freedom for the opening pressure of the security valve, which is determined by the valve opening area and the closing spring force, which can be selected rather randomly. In the following the invention is described in detail by means of embodiment examples with reference to the drawings, showing: Fig. 1 an embodiment according to the invention of an N.O. solenoid valve with activated coil, that is, in the closed state of the valve Fig. 2 the solenoid valve according to Fig. 1 in the open state of the valve Fig. 3 & 4 show an alternative embodiment of the solenoid valve according to the invention with activated or non-activated coil, respectively Fig. 5, 6 & 7 show enlarged details of different embodiments of valve seat and closing member Fig. 8 shows an embodiment of the closing member, in which the closing member is provided with a projecting edge co-operating with the armature Fig. 9 shows an embodiment according to the inven- tion of an N.C. solenoid valve The embodiment of a solenoid valve according to the invention shown in Figs. 1 and 2 comprises a coil 2 arranged around an armature guide 3 of an armature 4 and an armature return spring 5, so that the armature 4 can be brought to move towards the armature guide bottom 11 on activation of the coil and towards the valve seat 6 on de-activation of the coil, as the armature 4 is acted upon by the armature return spring 5, which acts upon the armature 4 with the armature guide bottom 11 as pressure reference. Further, the solenoid valve comprises a valve seat 6 and a closing member 7, which are pressed by a closing spring 9 in the direction of the valve seat 6, so as to close the valve opening 8 in the valve seat 6 in the activated state of the coil. When the armature is released from the activated position shown in Fig. 1 and moves towards the non- activated position shown in Fig. 2, the projecting edge 13 of the armature acts upon the closing member to perform a rocking movement around the valve seat, which, in view of this rocking movement is made with a rounded surface. In the embodiment shown in Figs. 1 and 2 the closing spring is arranged in the end of the armature 4 facing the valve seat 6, so that the closing spring uses the armature as pressure reference. The action on the closing member 7 from the closing spring 9 thus varies with the position of the armature 4. Alternatively, Figs. 3 and 4 show an embodiment, in which most elements are made as shown in Figs. 1 and 2 and are thus not explained, however, the closing spring 9 of the closing member 7 is arranged in a through-bore 10 in the armature 4, the closing spring 9 bearing on a pin 12, which is also arranged in the through-bore 10 in the armature 4, so that the pin 12 is surrounded by the armature 4 return spring 5 and the pin 12 bears on the armature guide bottom 11, so that the pressure reference of the closing spring 9, via the pin 12, is the armature guide bottom 11. At the front end of the closing spring 9 shown in Figs. 3 and 4 a cup 15 is arranged, which extends in the through-bore 10 in the armature 4, which results in a spring force acting upon the closing member 7, which is centred in relation to the valve seat 6. The embodiment of the valve seat 6 and the closing member 7 sketched in Fig. 5 comprises a plane closing member 7, which in the closed position bears on a plane surface 16, which is vertical to the valve opening 8 and extends in a certain radial distance from the valve opening 8. At increasing radial distance from the valve opening 8, the plane surface 16 is transformed into a curved roll-off surface 17 with a curvature radius Rj, after which the curved roll-off surface 17 at a further diameter increase is transformed to a cone-shaped bearing surface 18. With this embodiment the rocking movement of the closing member 7, which is produced by the armature 4 (not shown) acting upon the closing member in the direction of the arrow F, will be a rolling movement of the closing member 7 over the curved roll-off surface 17 finished by the closing member 7 bearing on the cone-shaped bearing surface 18. Accordingly, the embodiment of valve seat 6 and closing member 7 shown in Fig. 6 is made with a plane closing member 7, which is sealed towards the valve seat along a sealing surface 19 with a curvature with the radius R 2 , whereas in Fig. 5 the sealing takes place along the plane surface 16. As in Fig. 5 an increased radial distance from the valve opening 8 will cause the sealing surface 19 to transform into a first conic surface, which transforms to a curvature R 3 at increased radial distance, after which the valve seat 6 transforms into a different cone. Also this embodiment produces a rolling movement of the closing mem- ber 7 in relation to the valve seat 6 through the armature (not shown) acting in the direction of the arrow F. Fig. 7 roughs out an embodiment of the valve seat 6 and the closing member 7 in which the valve seat 6 is made with a plane surface 23 and the closing member 7 is made with a substantially ball-shaped surface 21, which can rock on the plane surface 23 of the valve seat 6, when the armature (not shown) acts upon the closing member 7 in the direction of the arrow F. Fig. 8 roughs out an alternative embodiment of the asymmetric acting of the armature 4 upon the closing member 7, in which the asymmetry of the action is produced by means of a projecting edge on the closing member 7, contrary to the embodiments shown in Figs. 1 to 4, in which the asymmetry is produced by a projecting edge 13 on the armature 4. Further, Fig. 8 shows that the armature 4 is arranged asymmetrically in relation to the valve seat 6, which also contributes to the production of the asymmetric action between the armature 4 and the closing member 7. Fig. 9 shows how the principle of the closing member 7 rocking in relation to the valve seat 6 can be made for the production of an N.C. solenoid valve. Fig. 9 shows the armature in the non-activated state. At one edge the armature 7 is provided with a hook-shaped projection 22, which seizes the rear of the closing member 7, so that on activation of the armature 4, that is an upward movement as shown in Fig. 9, the closing member 7 will be tilted in relation to the valve seat 6, thus opening the solenoid valve. Figs. 5 to 9 do not show a closing spring 9 for acting upon the closing member 7 in the direction of the closed posi- tion, as shown in Figs. 5 to 9, but obviously such a spring can be arranged between the closing member 7 and the armature 4, as shown in Figs. 1 to 4. Even though the solenoid valve 1 according to the invention is mainly described in connection with an embodiment as N.O. valve, the basic principle as shown for instance in Fig. 9, can also be made for production of an N.C. valve.

Claims: Patent Claims 1. Solenoid valve (1) comprising a coil (2) surrounding a guide (3) for an armature (4), the armature (4) being movable in the guide (3) through magnetising of the coil (2) and by means of a return mechanism (5), respectively, and a valve seat (6) co-operating with a closing member (7) for selectively, controlled by the armature (4) movement, opening or closing a valve opening (8) through the valve seat (6), characterised in that in relation to the armature (4) the closing member (7) is a separate unit activated by the armature (4) movement to making a rocking movement around a con- tact/touching point with the valve seat (6). 2. Solenoid valve according to claim 1, characterised in that the valve seat (6) has a rounded surface around which the closing member rocks. 3. Solenoid valve according to claim 1, characterised in that the valve seat (6) is made with a circular first plane surface (16) around the valve opening (8), which plane surface (16) at an increased radial distance from the valve opening is transformed into a curved roll-off surface with a curvature radius Ri , after which the curved roll-off surface turns into a cone-shaped contact surface (18) at further increased radial distance from the valve opening (8) . 4. Solenoid valve according to claim 1, characterised in that the valve seat (6) is made with a sealing surface (19) having a curvature radius R,, which at an increased radial distance from the valve opening (8) is trans- formed into a curved roll-off surface (20) with a cur- vature radius R^. 5. Solenoid valve according to claim 1, characterised in that the valve seat (6) is made with a plane surface (23) and the closing member (7) is made with a rounded, particularly ball-shaped, surface (21), which rolls on the plane surface (23) of the valve seat (6) during the rocking movement. 6. Solenoid valve according to any of the claims 1 to 5, characterised in that between the armature (4) and the closing member (7) there is a closing spring (9) for urging the closing member (7) against the valve seat (6) . 7. Solenoid valve according to any of the claims 1 to 5, characterised in that the closing member (7) is acted upon centrally by a closing spring (9) extending in a through-bore (10) in the armature (4), the pressure reference of the closing spring (9) being the bottom (11) of the armature guide. 8. Solenoid valve according to claim 7, characterised in that the closing spring (9) bears on a pin (12), which also extends in the through-bore (10) in the armature (4), the pin (12) being surrounded by the return spring (5) of the armature and both pin (12) and armature return spring (5) bearing on the bottom (11) of the armature guide. 9. Solenoid valve according to any of the claims 1 to " 8, characterised in that the armature (4) has a projecting edge (13) co-operating with the closing member (7), the closing member (7) being acted upon offset from the valve seat (6) centre outside the valve seat diameter. 10. Solenoid valve according to any of the claims 1 to 9, characterised in that the closing member (7) has a pro- jecting edge (14) co-operating with the armature (4), the closing member (7) being acted upon offset from the valve seat centre outside the valve seat diameter. 11. Solenoid valve according to any of the claims 1 to 10, characterised in that the armature (4) is arranged asymmetrically in relation to the closing member (7). 12. Method when using a solenoid valve according to any of the claims 6 to 11, characterised in that the solenoid valve (1) is connected so that the medium flows in via the valve opening (8) in the valve seat (6), the closing member (7), in the closed state, acting as security valve, which releases the medium flow, if the differential pressure exceeds a value determined by the area of the valve seat opening (8) and the force of the closing spring (9) .

Inventors: HAMMERICH CHRISTIAN, HAMMERICH, CHRISTIAN
Applicants: DANFOSS AS, HAMMERICH CHRISTIAN, DANFOSS A/S, HAMMERICH, CHRISTIAN
Application year: 1998
Main classification: F16K1
IPC codes: F16K31