Two-stage solenoid valve for an electropneumatic valve control unit
View Patent ↗A two-stage solenoid valve for an electropneumatic valve control unit, e.g., a pilot control unit of a pressure modulator, includes a solenoid system to which a first and second current intensity can be applied as well as a solenoid valve device with a primary side connectable to a first compressed-air supply and a secondary side connectable to a second compressed-air supply. A primary valve encompassing an adjustable primary armature biased by a primary armature spring is provided on the primary side, and a secondary valve encompassing an adjustable secondary armature biased by a secondary armature spring is provided on the secondary side. The solenoid valve device can be a valve cartridge insertable from one side. Diameters of a front (in relation to insertion direction) region and a central region of the valve cartridge are smaller than or equal to the diameter of a rear region of the valve cartridge.
1. A two-stage solenoid valve for an electropneumatic valve control unit, comprising:
a solenoid system energizable with a first and second current intensity;
a solenoid valve cartridge insertable into said solenoid system via a side of said valve control unit, said solenoid valve cartridge having a primary side connectable to at least one first compressed air port and a secondary side connectable to at least one second compressed air port, said solenoid valve cartridge having a stepped body and comprising a rear region, a front region, and a central region, wherein:
said rear region has a larger diameter than diameters of said front and central regions;
said front region houses a secondary armature spring;
said central region at least partly houses a primary armature and a secondary armature; and
said rear region houses a primary armature spring;
a primary valve disposed on said primary side, said primary valve having said primary armature displaceable pre-loaded by said primary armature spring for bearing on at least one primary valve seat; and
a secondary valve disposed on said secondary side, said secondary valve having said secondary armature displaceably pre-loaded by said secondary armature spring for bearing on at least one secondary valve seat, said secondary armature having a smaller cross section than said primary armature.
2. The solenoid valve according to claim 1 , wherein valve seats of said front and rear regions are joined to said stepped body.
3. The solenoid valve according to claim 1 , wherein an armature guide tube of said primary armature is housed at least partly in said central region.
4. The solenoid valve according to claim 1 , wherein said primary valve and said secondary valve have a common core.
5. The solenoid valve according to claim 4 , wherein said common core is formed in one piece.
6. The solenoid valve according to claim 1 , wherein said secondary valve is disposed proximate a front region of said solenoid valve cartridge and said primary valve is disposed proximate a rear region of said solenoid valve cartridge.
7. The solenoid valve according to claim 1 , wherein said primary side communicates with a compressed air port for supplying compressed air, and said secondary side communicates with a vent port for discharging compressed air.
8. The solenoid valve according to claim 1 , wherein said primary valve is a 2/2-way valve.
9. The solenoid valve according to claim 1 , wherein said secondary valve is a 3/2-way valve.
10. The solenoid valve according to claim 9 , wherein said secondary valve has a first output for at least one of a control pressure port and an air admission port and a second output for said vent port.
11. The solenoid valve according to claim 10 , wherein:
in a de-energized state, said primary valve is open and said secondary valve leaves said air admission port open and shuts off said vent port,
at a first lower current intensity, said primary valve is closed and said secondary valve leaves said air admission port open and shuts off said vent port, and
at a second higher current intensity, said primary valve is closed and said secondary valve releases said vent port and leaves said air admission port open, whereby said vent port and said air admission port are in communication with one another for venting.
12. The solenoid valve according to claim 1 , wherein said solenoid valve cartridge is insertable into a blind bore of said valve control unit.
13. The solenoid valve according to claim 12 , wherein said valve cartridge is insertable with said secondary side into said blind bore and is fixable in said blind bore by initial pressurization.
14. The solenoid valve according to claim 1 , wherein said electropneumatic valve control unit is a pilot control unit of a pressure modulator.
15. The solenoid valve according to claim 2 , wherein said valve seats of said front and rear regions are joined to said stepped body by at least one of flanging, caulking and welding.
16. The solenoid valve according to claim 1 , wherein a spring constant of the primary armature spring is different than a spring constant of the secondary armature spring.
17. The solenoid valve according to claim 1 , wherein said front region is formed continuously with said central region.
18. The solenoid valve according to claim 1 , wherein said front region is disposed on said secondary side, said rear region is disposed on said primary side, and said central region is disposed between said front region and said rear region.