Electromagnetic actuating unit for a hydraulic directional control valve and method for the assembly thereof

1. An electromagnetic actuating unit for a hydraulic directional control valve, comprising:

a housing for conducting a magnetic flux;

a coil for generating a magnetic field in the housing;

a yoke unit having a yoke in the coil, a yoke plate axially adjacent the coil and a first bearing point;

a pole core unit having a pole core in the coil and a second bearing point;

an armature unit arranged in the coil having an armature and a pressure pin acting as an actuator, the armature unit is mounted, so as to be slidable in a direction of a longitudinal axis, in the first bearing point and in the second bearing point;

wherein, in a first assembly state of the actuating unit, at least one of the first bearing point or the second bearing point is radially movable and, in a second assembly state, after a coaxial alignment of the first bearing point and the second bearing point, at least one of the first bearing point and the second bearing point is fixed; and

a centering sleeve arranged in the coil, the centering sleeve servers for a radial alignment of the first bearing point and the second bearing point during assembly.

2. The actuating unit as claimed in claim 1 , wherein the centering sleeve receives the yoke unit and the pole core unit during assembly and serves for an axial and/or a radial positioning of the first bearing point and the second bearing point by axial and/or radial positioning of the yoke unit and the pole core unit.

3. The actuating unit as claimed in claim 1 , wherein the pressure pin is mounted at each end in one of the first bearing point and the second bearing point, and the armature has a central bore through which the pressure pin is guided and axially fixed.

4. The actuating unit as claimed in claim 1 , wherein a fixing point is provided between the yoke plate and the housing.

5. The actuating unit as claimed in claim 4 , wherein the fixing point is formed by an adhesive bond point, a solder point, a weld seam, a crimped connection or by folded-over retaining lugs.

6. The actuating unit as claimed in claim 1 , wherein a clearance fit and a fixing point are provided between the pole core and the housing, the fixing point is formed by an adhesive bond point in a clearance fit or a solder point or a weld seam.

7. A method for the assembly of an electromagnetic actuating unit for a hydraulic directional control valve, comprising the following steps:

a, assembling a yoke unit, an armature unit, a pole core unit and a coil with at least one of two bearing points being floatingly mounted in the yoke unit or in the pole core unit;

b. coaxially aligning of the two bearing points with at least one of the two bearing points being radially movable While the two bearing points are being aligned; and

c. fixing the bearing point, which is floatingly mounted,

wherein the coaxially aligning of the bearing points takes place by insertion of the yoke unit and of the pole core unit into a centering sleeve arranged in an interior of the coil.

8. The method as claimed in claim 7 , wherein the fixing of the bearing point which is floatingly mounted takes place by pressing-in, adhesive bonding, soldering, welding, crimping or clamping or a combination of the connecting techniques.

9. The method as claimed in claim 8 , wherein the fixing of the bearing point which is floatingly mounted takes place by adhesively bonding the coil into the pole core unit and adhesively bonding the yoke unit to the coil.

10. The method as claimed in claim 8 , wherein the fixing of the bearing point which is floatingly mounted takes place by adhesively bonding or soldering or welding the yoke unit to the pole core unit.

11. The method as claimed in claim 8 , wherein the fixing of the bearing point which is floatingly mounted takes place by adhesively bonding or soldering or welding the pole core to the magnet housing.