EP2308064B1 - Solenoid arrangement and valve arrangement - Google Patents

Abstract

A solenoid arrangement comprises a pole tube which is axially subdivided into a pole core section, a transition section, and a tube section. A magnetic flux between the pole core section and the tube section is interrupted by the transition section. An armature is movably guided in the pole tube and has, at its end facing the pole core section, a flange which axially projects from an end face. According to the invention, the pole core section has a stepped depression into which the armature can plunge and which, starting from the transition section, is subdivided into an annular collar, a shoulder, and a notch which is set back axially and radially. An axial dimension of the collar exceeds an axial dimension of the flange.

Description

The invention relates to a Hubmagnetanordnung with a pole tube. The invention further relates to a valve arrangement.

Such a solenoid assembly is known from DE 197 07 587 A1 known. A pressure-tight solenoid has, in addition to the pole tube, a coil for actuating an armature which is axially movably guided in an armature space of the pole tube. The pole tube consists essentially of a pole piece - also Polkern - which can be screwed via a central thread in a valve housing, a non-magnetic intermediate piece and a subsequent to this piece of pipe which is closed on the side facing away from the pole piece frontally by means of a serving as a stroke limiter component , The pole piece, the intermediate piece, the pipe section and the stroke limiter delimit the armature space for the armature cooperating with the coil. This is connected to a plunger, which passes through the pole piece in the axial direction and is used to actuate a valve spool of a hydraulic valve. The non-magnetic spacer serves to divert the magnetic flux into the armature. This non-magnetic intermediate piece may be formed annular cone-shaped for achieving a favorable force-displacement curve. In the production of such a shape but associated with effort. Especially With simple solenoids, the simplest possible geometry of the intermediate piece should be used.

Examples of how an anchor can be contoured in conjunction with a pole piece are in the DE 103 27 875 B4 specified. However, there are given in terms of production quite expensive shaped pole pieces.

In the case of conventional lifting magnets which are simple in terms of production, the force-displacement characteristic is usually not optimal at present. For the actuation of hydraulic switching or proportional valves namely high, the operation opposite flow forces are already at low to medium strokes of the control piston to overcome, which increase only slightly in the course of the stroke. In addition, the flow forces are often effective only on a narrow portion of the stroke. In contrast, conventional solenoids only develop a high force in the last stroke section. Apart from that, the power development is little localized and is usually evenly formed with a slight incline over a large stroke range. This requires the use of large-sized solenoid solenoids with correspondingly high material and energy expenditure.
The JP-09306731 A , which is considered as the closest prior art, shows an electromagnet in which a pole tube is formed by a Polkernstück and a thin tube piece which is plugged into an outer circumferential groove of the Polkernstücks. The Polkernstück has a double-stepped recess. An associated anchor has a double stepped collar. The second step or recess has a lower height than the first step.
It is therefore an object of the present invention to provide an improved solenoid assembly, which in particular can be adapted constructively to the operating force characteristic of a valve in a simple manner.

This object is achieved by a solenoid arrangement with the features of patent claim 1.

The formation of a collar at the anchor and a stepped recess in the pole core with a recess for receiving the collar can be realized in the production with simple means. The greater length of the collar compared to the collar on the armature causes on the stroke of the armature during the actuation process successively and at a distance edges or boundary lines or boundary surfaces of the pole piece with corresponding sections of the armature come to cover. First, an overlap between an end-side inner boundary line of the collar with the end face of the anchor. When the stroke continues, the collar then dips past a shoulder of the recess and into the recess. In this way, the force-stroke curve can be designed so that on a defined portion of the stroke, namely on the path of the armature between the two edges, a targeted plateau-shaped increase in the force. The Hubmagnetanordnung invention is simple and inexpensive to produce. It can be optimally adapted to the flow force characteristics, e.g. to adapt to switching valves. By means of the described design, the force even decreases again in the end region of the armature stroke, ie after immersion of the collar in the depression. This contributes to a lower stress on the anti-stick lens, a lower switching noise and a faster turn-off time. Overall, with the valve arrangement according to the invention with lower electrical power higher valve forces or flow forces can be overcome and in particular switching valves are operated safely and efficiently.

The object is accordingly also achieved by a valve arrangement; which has such a Hubmagnetanordnung.

In particular, the valve is combined with a stroke characteristic that is optimally adapted to the flow force conditions of the valve in its characteristic curve. The adjustment is structurally simple on the geometric aspect ratios at the collar and waistband. In a vivid way, for example, the Position of said edges adapted to the course of the opening cross-section of the valve on the Betätigungshub.

Advantageous embodiments of the present invention are specified in the subclaims.

According to a preferred embodiment of the present invention, the transition section is formed of a non-magnetizable material and a separation surface between the transition section and the collar is aligned substantially perpendicular to a central axis of the pole tube. Especially with such simple geometries on the separating surface can be achieved by means of the inventive design of armature and Polkernabschnitt well adapted to a valve characteristics. The manufacture is e.g. using the resistance welding technique - e.g. capacitor discharge welding or center frequency welding - for joining pole piece and separator ring, which forms the transition section, particularly simple.

Preferably, an anti-sticking disc is arranged between the end face of the armature and the shoulder of the pole piece. There is a comparatively large area available, so that the anti-slug also withstands high loads. The anti-stick disc could even be mounted on the collar and thus rest on the end face of the anchor captive.

The geometry described anchor and Polkernabschnitt can also be cleaned to damp a stop of the anchor on the pole core. For this purpose, a radial gap between the collar and the depression is sized accordingly. The fluidic damping then takes place via the displacement of fluid from an outer annular space between the armature - more precisely its end face and the collar - and the shoulder of the recess.

Preferably, in a valve arrangement with the Hubmagnetanordnung invention, a first position of the armature, wherein the end face of the armature faces a boundary line of the end face of the collar, a low degree of opening of the valve, ie a position of the valve piston at the flow forces are relevant. A second position of the armature, in which an end face of the collar of the armature of the shoulder facing the recess, corresponds to a stronger degree of opening of the valve, in which the valve piston has almost completed its opening stroke and in which the flow forces relax again. This can e.g. Be 25% and 75% of the opening stroke of the valve piston.

Figur 1

zeigt eine Hubmagnetanordnung in schematischer Schnittdarstellung,

Figur 2

stellt einen Ausschnitt aus Figur 1 um den Bereich des Arbeitsluftspalts vergrößert dar und

Figur 3

zeigt eine Kennlinie der erfindungsgemäßen Hubmagnetanordnung im Vergleich mit einer Strömungskraftkennlinie eines Ventils und einer Kennlinie eines herkömmlichen Hubmagneten.

Hereinafter, the present invention and its advantages will be explained in more detail with reference to the embodiment shown in the figures.

FIG. 1

shows a Hubmagnetanordnung in a schematic sectional view,

FIG. 2

represents a section FIG. 1 around the area of the working air gap enlarged and

FIG. 3

shows a characteristic of the Hubmagnetanordnung invention compared with a flow force characteristic of a valve and a characteristic of a conventional solenoid.

In FIG. 1 a solenoid assembly 1 for actuating a valve spool of a hydraulic valve (not shown) is shown. The Hubmagnetanordnung 1 has a fluid-tight pole tube 3. The pole tube 3 has a Polkernabschnitt 5, a separating section 7 - in the claims also referred to as a transition section -, a pipe section 9 and a closure piece 11 - also called stroke limitation. The pole core section 5, the separation section 7, the pipe section 9 and the closure piece 11 form a circular cylindrical receiving space for an armature 13. A plunger 15 is guided in the pole core section 5 and emerges on the outer end side of the pole core section 5 from this.

By means of a thread 17 on the pole core section 5, the pole tube 3 is screwed into a valve housing of the hydraulic valve. On the pole tube 3, a coil component is pushed. This includes the actual coil 19 and a housing made of magnetic material (not shown), which represents a yoke for a magnetic circuit including the pole tube 3. The separating section 7 interrupts the magnetic circuit in the region of the working air gap 21 between the armature 13 and the pole core section 5 and forces the magnetic field lines from the pole core section 5 to the armature 13.

The armature 13 is provided at its the Polkernabschnitt 5 facing end face with a projecting from the end face 22 collar 24. On the annular end face 22 an anti-stick washer 25 is placed. If necessary, this can be mounted on the collar 24 for attachment. The armature 13 pass through axial fluid compensation channels 27. These open into an end face 29 of the collar 24.

The Polkernabschnitt has on the inside a stepped recess 31 for receiving the armature portion facing it. This depression 31 is divided as follows: A collar 33 protrudes annularly beyond an inside end face 34 of the pole core section 5. The end face 34 further forms a shoulder for a central depression 36.

The inner diameter of the collar 33 corresponds to the inner diameter of the separating section 7 and the pipe section 9. The inner diameter of the recess 36 is selected so that the collar 24 can dip into the depression 36. A fluidic damping of the armature movement in the end position can be achieved via a gap between collar 24 and recess 36. The damping volume is located in one of the collar 24, the end face 22, the end face 34 and the collar 33 limited annular space.

The area around the working air gap 21 is in FIG. 2 shown enlarged. Evident is the substantially circular tubular shape of the separating section 7, which has no cone. A pole tube 3 with such a separating section 7 can be added, for example, by electrical resistance welding of tubular or cup-shaped semi-finished products. With regard to the anti-stick disc 25 'is a variant of FIG. 1 shown. The anti-stick disc 25 'is inserted into the working air gap 21 and rests on the end face 34. There it can be attached if necessary.

The collar 24 is bounded at the end by an outer annular edge 41. Likewise, at the transition from the end face 22 of the armature in the lateral surface of an annular edge 40 is present. On the inner wall of the pole tube 3 is located at the transition from the collar 33 to the separation section 7 an imaginary, circular boundary line 42 at which the magnetizability of the pole tube 3 changes abruptly in the axial course. Between the end face 34 and the recess 36, the annular edge 43 is present in the stepped recess 31 of the Polkernabschnitts 5. This can be bevelled or rounded.

The FIG. 3 shows a force-stroke characteristic 50 of a conventional Hubmagnetanordnung, eg an actuating magnet, as in the above-mentioned DE 197 07 587 A1 describes a force-stroke characteristic curve 52 of the solenoid assembly 1 according to the invention and an actuating force-stroke characteristic curve 54 (dashed line) of a typical directly actuated switching valve of the nominal size 6 or 10. The hub is divided into areas B1 to B6. The length of the areas is in the order of, for example, 1 to 2 mm. The characteristic curve 54 of the valve has a baseline B1 rising to baseline, which is due to the usual action on the valve piston with a return spring and by the friction of the valve piston in the valve bore. However, a large effect on the characteristic curve 54 has the forces acting on the valve piston during the opening process. These cause the recognizable in the areas B2 and B3 of the characteristic curve 54 strong increase in the required operating force. After complete switching through the valve, the flow forces are no longer relevant, as the curve 54 in area B1 shows.

In an electrical actuation of the solenoid assembly 1 by energizing the coil 19, the following process takes place: From an end position on the stroke limiter 11 or a contact on the plunger 15 - as in FIG. 1 shown - the armature 13 begins to move in the direction of the Polkernabschnitts 5. The movement begins in the area B6 or at the transition from the area B5 to the area B4 - here is an investment on the plunger 15 - with initially low power, as the line 52 shows. The area B3 is the portion of the movement sequence at which the annular edge 40 of the armature 13 passes over the boundary line 42 to the collar. Between the annular edge 40 and the boundary line 42 is a high density of magnetic field lines in the working air gap. When immersing the armature 13 with the annular edge 40 in the collar 33, therefore, there is a significant decrease in the present in the working air gap magnetic field energy. Due to this, the characteristic 52 steeply increases from the area B4 to the area B3.

After the armature 13 has passed the boundary line 42, a further area of high field line density is present between the annular edge 41 on the collar 24 of the armature 13 and the annular edge 43 of the stepped recess 31. Upon further immersion of the armature 13 in the stepped recess 31 can therefore the high force is maintained until the anchor with the collar 31 dips into the recess 36. This can be seen in the characteristic curve 52 in the area B2 and at the transition from the area B2 into the area B1. In the further path of the armature 13, only the volume in the depression 36 filled with a few magnetic field lines is reduced. The force decreases accordingly in the area B1. The movement ends when the armature 13 with the anti-stick disc 25 or 25 'rests against the end face 34. Wiping the end face 29 of the collar 24 and the bottom of the recess 36 remains a gap.

By selecting the axial arrangement of the boundary line 42 and the annular edge 43, i. the length of the collar 33, and by a suitable length of the collar 24 so a plateau-shaped increase in the magnetic force over a relatively wide stroke range in the force-stroke characteristic 52 of the solenoid assembly 1 can be achieved. The length difference between the collar 33 and the collar 24 results in about the length of the plateau of the force-stroke characteristic curve 52 in the area B2 and B3. The magnetic force is correspondingly reduced at the beginning and in the final phase of the armature stroke - areas B4 to B6 and area B1 - respectively compared to the characteristic 50 of a conventional magnet of the same electric power.

The described solenoid assembly 1 is ideal for operating a switching directional control valve. The typical Betätigungskraftkennlinie 54 on the stroke of the valve spool has, as I said, a significant increase due to flow forces in the increase of the opening cross section, until the full valve opening is reached. This can be seen as a plateau of the actuating force in the areas B2 and B3 of the characteristic 54. The solenoid assembly 1 is now inter alia by means of the lengths of collar 24 and collar 33 designed so that the plateau of the actuating force in the characteristic curve 54 is covered by the plateau-like increase in the magnetic force in the characteristic curve 52. So there is enough magnetic force to safely switch the valve on every section of the armature stroke. Through the steep Magnetic force increase in the range B4 of the characteristic curve 52 is already at the beginning of the stroke of the valve spool on which the bias of the return spring must be overcome, sufficient magnetic force available. The magnetic force decrease in the region B1 coincides with the decrease in the flow forces in a fully connected valve. In addition, due to the decrease in force, the anti-stick disc 25 or 25 'is less heavily loaded by the impact of the armature 13. The impact sound is also low. The armature 13 returns after switching off the coil 19 faster in its original position.

On the basis of the embodiment, the use of the Hubmagnetanordnung invention was described in a normally closed switching directional control valve for carrying out the opening stroke. Of course, the application can also be used in a normally open switching switching valve to perform the closing stroke. Further, the Hubmagnetanordnung invention can also be used to operate a proportional valve. In this case, several arranged in stages collars can be provided on the anchor and a corresponding multi-stepped depression on the pole piece, which receives the leaflets each in suitable depressions, are used.

Another variant is to form the collar 33 conical. Then, by the previously described shape of the armature 13 with collar 24 and through the stepped recess 31, the proportional range can be extended to a larger stroke range.

reference numeral

1

lifting magnet

3

pole tube

5

pole core

7

separating section

9

pipe section

11

closing piece

13

anchor

15

tappet

17

thread

19

Kitchen sink

21

Working air gap

22

face

24

Federation

25

anti-adhesion disc

25 '

anti-adhesion disc

27

Fluid balancing passages

29

End face of the waistband

31

Stepped depression

33

collar

34

face

36

depression

40

annular edge

41

annular edge

42

boundary line

43

annular edge

50

Force-stroke characteristic

52

Force-stroke characteristic

54

Operating force-stroke characteristic of the valve

Claims (10)

1. Solenoid arrangement comprising
   a pole tube (3) which, in the axial direction, is made up of a pole core section (5), a transition section (7) and a tube section (9), with a magnetic flux between the pole core section (5) and the tube section (9) being interrupted by the transition section (7), and
   an armature (13) which is guided in a moveable manner in the pole tube (3) and has, at its end face which faces the pole core section (5), a collar (24) which protrudes axially out of an end surface (22),
   with the pole core section (5) having a stepped recess (31) which the armature (13) can enter and which - starting from the transition section (7) - is made up of an annular flange (33), a shoulder (34) and a countersunk portion (36) which is axially and radially recessed,
   and with an axial extent of the flange (33) projecting beyond an axial extent of the collar (24),
   characterized in that
   an inside diameter of the flange (33) corresponds to an inside diameter of the transition section (7) and an inside diameter of the tube section (9).
2. Solenoid arrangement according to Claim 1, characterized in that the transition section (7) is formed from a non-magnetizable material, and in that a separating surface between the transition section (7) and the flange (33) is oriented substantially perpendicular to a centre axis of the pole tube (3).
3. Solenoid arrangement according to Claim 1 or 2, characterized in that an anti-adhesion disc (25) is arranged on the end surface (22) of the armature.
4. Solenoid arrangement according to Claim 1 or 2, characterized in that an anti-adhesion disc (25') is arranged on the shoulder (34) of the recess (31).
5. Solenoid arrangement according to one of the preceding claims, characterized in that a ratio of the axial extent of the collar (24) and the axial extent of the flange (33) is between 1 to 2 and 1 to 4, for example 1 to 2, 1 to 3 or 1 to 4.
6. Solenoid arrangement according to one of the preceding claims, characterized in that a radial gap between the collar (24) and the recess (36) is of such a size that a movement of the armature (13) to an end position on the pole core section (5) is fluidically damped.
7. Valve arrangement having a housing, having a valve slide which is guided in a moveable manner in a valve bore within the housing and by which a control cross section of a fluidic connection can be adjusted, and having a solenoid arrangement (1) according to one of Claims 1 to 6 which is provided for the purpose of operating the valve slide.
8. Valve arrangement according to Claim 7, characterized in that a first position of the armature (13), in which position the end surface (22) of the armature (13) is situated opposite a boundary line (42) of the flange (33) which is on the inside on the transition section side, and a second position of the armature (13), in which position an end surface (29) of the collar (24) of the armature (13) is situated opposite the shoulder (34) of the recess (31), are arranged in accordance with an expected force profile (54) of flow forces which act on the valve slide during an opening process.
9. Valve arrangement according to Claim 8, characterized in that the first position of the armature (13) corresponds to a low degree of opening of the control cross section, and in that the second position of the armature (13) corresponds to a comparatively large, in particular virtually completely open, control cross section.
10. Valve arrangement according to Claim 8 or 9, characterized in that the first position of the armature (13) corresponds to a stroke of 20% to 40%, in particular 25%, of a stroke of the valve slide which is associated with the opening process, and the second position of the armature (13) corresponds to a stroke of 60% to 85%, in particular 75%, of the stroke of the valve slide which is associated with the opening process.

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