Electrohydraulic pilot control with two pressure control valves

Abstract

Electrohydraulic pilot control means (1) for a hydraulic device which can be a proportional directional valve, an adjusting pump or an adjusting motor, which pilot control means contains two proportionally acting pressure control valves (3) and is provided with a control block (2) which accommodates the hydraulic valve parts (4) in holes and to which the associated proportional magnets are flange-connected, wherein the proportional magnets have a common electrical plug connection (5) and wherein the two proportional magnets (3) are joined to form an assembly by being encapsulated with plastic, the said assembly being fastened to the control block (2) and, in this case, being precisely oriented relative to the valve components (4), which are accommodated in the control block, by means of positioning aids which act perpendicular to the movement direction of armatures.

Claims

1. An electrohydraulic pilot control for a hydraulic device, the pilot control comprising: two proportionally acting pressure control valves; and a control block which accommodates a group of hydraulic valve components in holes and to which two proportional magnets are flange-connected; wherein the two proportional magnets are joined to form an assembly by being encapsulated with plastic and have a common housing of an electrical plug connection, which housing is cohesively connected to the proportional magnets, wherein the assembly of the proportional magnets is fastened to the control block and, is oriented relative to the valve components, which are accommodated in the control block, by a positioning means for acting perpendicular to the movement direction of magnet armatures; wherein the proportional magnets are both equipped with in each case one bow-shaped metal sheet which guides magnetic flux, and have a common flange for fastening to the control block, wherein the flange is reinforced by extensions of the metal sheets; wherein the positioning means provides relative lateral positioning of the assembly of the proportional magnets to the valve components by use of projections extending from valve sleeves in the control block that engage matching cavities defined in magnet cones of the proportional magnets; or wherein the positioning means provides relative lateral positioning of the assembly of the proportional magnets to the valve components by use of projections extending from the magnet cones that engage in receiving holes defined in the valve sleeves.

2. The electrohydraulic pilot control according to claim 1, wherein the proportional magnets have pressure tubes for mounting the magnet armature, the pressure tubes each being welded to the cone of the proportional magnets, wherein the magnet armature is mounted in the pressure tubes.

3. The electrohydraulic pilot control according to claim 1, wherein the valve sleeves of the proportionally acting pressure control valves are inserted into the control block.

4. The electrohydraulic pilot control according to claim 1, wherein the control block additionally contains a pressure reduction valve for providing supply pressure for the pressure control valves.

5. A method for testing the electrohydraulic pilot control according to claim 1, wherein the valve components are fitted in the control block, the magnet assembly comprising the two pressure control valves is flange-connected to the control block, and the operation of the two pressure control valves are tested in this state during the course of series production.

6. The method for testing the electrohydraulic pilot control according to claim 5, wherein the two pressure control valves in the control block are tested together with a pressure reduction valve.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

(2) FIG. 1 shows a control block with two pressure control valves, a pressure reduction valve and a return spring, having an interface between the magnet assembly and the control block; and

(3) FIG. 2 shows the interface between the magnet assembly and the control block.

(4) Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION

(5) Exemplary embodiment: FIG. 1 shows an electrohydraulic pilot control 1 which contains two proportionally acting pressure control valves, the proportional magnets 3 of the said pressure control valves being provided with a common encapsulation 7 which is composed of plastic. The hydraulically acting valve components 4 are inserted into a control block 2 and the proportional magnets 3 are fastened to this control block 2 by a flange 13. The position of the proportional magnets 3 is secured by the flange 13 and the flange-connection area of the control block 2 in the movement direction of the magnet armature 18; the position of the proportional magnets is secured by projections 23 of the magnet cones 15, which are surrounded by the receiving holes 11 for the valve sleeves 6 in the control block 2, perpendicular to the movement direction.

(6) The proportional magnets 3 each have a bow-shaped metal sheet for magnetic flux guidance 12; the two metal sheets are extended into the flange 13 in order to reinforce the flange 13. In each case, one pressure tube 14, which mounts the magnet armature 18 indirectly by the bearing bush 16, serves to guide the magnet armature 18.

(7) The magnet armature 18 operates the valve slide 17, which is mounted in the valve sleeve 6, and, together with the valve slide 17, fulfils the valve function.

(8) The control block 2 also accommodates the return spring which returns the hydraulic appliance, which is adjusted by the electrohydraulic pilot control 1, to the central position and a directionally proportional force counters the actuating pressure of the pressure control valves.

(9) The two pressure control valves are supplied with pressurized liquid by the hydraulic appliance, which is to be adjusted, by the pressure reduction valve 22. The pressure reduction valve 22 is also installed in the control block 2.

(10) As an alternative to the manner of securing the proportional magnets shown in FIG. 1, FIG. 2 shows a manner of securing the proportional magnets by projections 23 of the valve sleeves 6 out of the control block 2 and cavities, which match the said projections, in the magnet cones 15.

(11) Exemplary Series Test Method:

(12) In order to test the electrohydraulic pilot control during the course of series production, all the components of the pilot control, specifically the valve components 4, the proportional magnets 3, the return spring and the pressure reduction valve 22, are mounted in or on the control block 2. In this state, the control block is placed in a test stand and the hydraulic lines for the inflow and the outflow of the pressurized liquid are connected. An electrical actuator is connected to the electrical plug connection 5 by a cable. Furthermore, pressure sensors are connected to the output lines of the pressure control valves. In this state, the pressure control valves are tested, for example, characteristic curves of the pressure are recorded as a function of the electric currents. Independently of this, the force/movement characteristic curve of the return spring is determined with suitable measuring appliances. The return spring always stays given relevant pilot control.

(13) The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

LIST OF REFERENCE SYMBOLS

(14) 1. Pilot control 2. Control block 3. Proportional magnet 4. Valve components 5. Electrical plug connection 6. Valve sleeve 7. Encapsulation of the proportional magnets 11. Receiving hole 12. Metal sheet for magnetic flux guidance 13. Flange 14. Pressure tube 15. Magnet cone 16. Bearing bush 17. Valve slide 18. Magnet armature 22. Pressure reduction valve 23. Projection