DE102018112579A1 - Method for determining the wear of a magnet valve with coated armature surface - Google Patents

Abstract

The present invention relates to a method for determining the wear of a coated-armature coated magnetic valve (12), comprising the following steps:
- Detecting the interlinked magnetic flux over the current during the anchor flight of an armature (26) of the solenoid valve (12) in the intact state to establish a Psi-I reference curve;
- Definition of at least one threshold for deviation from the Psi-I reference curve as an indicator of accepted degree of wear;
- Measurement of the interlinked magnetic flux over the current during the anchor flight of the armature (26) of the solenoid valve (12) during operation of the solenoid valve (12);
- Check whether the measurement is below or above the threshold deviation from the Psi-I reference curve.
In addition, the present invention relates to a system (10) for determining the wear of a magnet valve (12) with coated armature surface.

Description

The present invention relates to a method for determining the wear of a magnet valve with coated armature surface and a system for determining the wear of a magnet valve with coated armature surface.

Solenoid valves with an integrated core tube assembly are already known from the prior art, for example from the DE 10 2012 101 634 A1 , The moving parts of these solenoid valves are subject to wear during operation.

In this core tube assembly may be provided coated with a non-metallic layer anchor, which is movably guided in the armature guide tube. By switching the solenoid valve rubs the armature on the wall of the armature guide tube, whereby the abrasion of the armature surface and the armature guide tube is formed.

Once this coating is worn and parts of the base material of the anchor are exposed, wear increases significantly.

It would be important to be able to recognize this wear.

For certain solenoid valves, however, determining the state of wear of the moving parts is not possible without destruction.

In order to determine the state of wear of these solenoid valves, thus a method is needed, which can determine the state of wear of the solenoid valve destructive. The test should be used for sorting out worn solenoid valves in the industrial reprocessing process (re-manufacturing).

It is therefore the object of the present invention to develop a method and a system for a solenoid valve of the type mentioned in an advantageous manner, in particular to the effect that the determination of the state of wear of a solenoid valve is possible nondestructive.

• - Erfassung des verketteten magnetischen Flusses über den Strom während des Ankerfluges eines Ankers des Magnetventils im intakten Zustand zur Erstellung einer Psi-I-Referenzkurve;
• - Definition wenigstens eines Schwellwertes zur Abweichung von der Psi-I-Referenzkurve als Indikator für akzeptierten Verschleissgrad;
• - Messung des verketteten magnetischen Flusses über den Strom während des Ankerfluges des Ankers des Magnetventils im Betrieb des Magnetventils;
• - Überprüfung, ob die Messung unterhalb oder oberhalb des Schwellwertes zur Abweichung von der Psi-I-Referenzkurve liegt.

This object is achieved by a method for determining the wear of a solenoid valve with coated armature surface with the features of claim 1. Thereafter, it is provided that in a method for determining the wear of a solenoid valve with coated armature surface, the following steps are performed:

• - Detecting the interlinked magnetic flux over the current during the anchor flight of an armature of the solenoid valve in the intact state to create a Psi-I reference curve;
• - Definition of at least one threshold for deviation from the Psi-I reference curve as an indicator of accepted degree of wear;
• - Measurement of the chained magnetic flux over the current during the anchor flight of the armature of the solenoid valve during operation of the solenoid valve;
• - Check whether the measurement is below or above the threshold deviation from the Psi-I reference curve.

• Bei dem Verschleiß der Ankerbaugruppe eines Magnetventils wird die Beschichtung abgetragen. Sobald das Grundmaterial freiliegt, ändert sich die Materialpaarung im Reibkontakt zwischen Anker und Ankerführungsrohr von Beschichtung / Stahl zu Stahl / Stahl. Die Materialpaarung Stahl / Stahl hat einen etwa fünf Mal höheren Reibkoeffizient als die Materialpaarung Beschichtung (beispielsweise Kunststoff, insbesondere PTFE) / Stahl. Der höhere Reibkoeffizient bewirkt eine höhere Widerstandskraft während des Ankerfluges. Dadurch ist das Verhältnis aus zurückgelegtem Weg und der Ankerflugzeit („Geschwindigkeit“) insgesamt geringer.

The invention is based on the basic idea that a non-destructive determination of the magnetic curve's sag is determined on the basis of the characteristic curve concerning the chained magnetic flux across the current during the armature flight of the armature of the solenoid valve. This is based on the following considerations:

• During wear of the armature assembly of a solenoid valve, the coating is removed. As soon as the base material is exposed, the material pairing changes in frictional contact between armature and armature guide tube from coating / steel to steel / steel. The material combination steel / steel has about five times higher coefficient of friction than the material combination coating (for example, plastic, especially PTFE) / steel. The higher coefficient of friction causes a higher resistance during the anchor flight. As a result, the ratio of distance traveled and the anchor flight time ("speed") is lower overall.

In addition, a correlation between the bounce behavior of the armature on the damping elastomer and the wear of the coating of the armature is observed. The weaker the severity of the bouncing of the anchor, the higher the abrasion of the coating on the anchor drops.

According to the invention, the concatenated magnetic flux is measured across the stream (equidistant time intervals). The measured data are recorded non-destructively. The curve recorded here is called the Psi-I curve. The gradient of the Psi-I curve during anchor flight is a measure of the anchor airspeed. This gradient is determined by the solenoid valves with intact coating and serves as a setpoint. The scattering gives the tolerance limits.

Bouncing affects the slope of the Psi-I curve at the anchor impact point. To determine the tolerance limits, boundary patterns are used.

Furthermore, it can be provided that the detection of the chained magnetic flux done electrically via the electricity. This allows easy and reliable detection.

Furthermore, the present invention relates to a system for determining the wear of a magnet valve with coated armature surface. Thereafter, it is contemplated that a system for determining the wear of a coated armature surface solenoid valve having at least one reference memory having at least one Psi I reference curve describing the interlinked magnetic flux across the current during the armature flight of an armature of the solenoid valve when intact, at least a setpoint memory, in which at least one threshold value for deviation from the Psi-I reference curve is stored as an indicator of accepted degree of wear, at least one measuring element, by means of which at least one measurement of the chained magnetic flux via the current of the armature of the solenoid valve during operation of the solenoid valve feasible is, and at least one test means by means of which it is verifiable whether the measurement is below or above the threshold value for deviation from the Psi-I reference curve.

The magnetic flux is a physical quantity for describing the magnetic field. It is - analogous to the electric current - the result of a magnetic voltage and flows through a magnetic resistance. Since even the vacuum represents such a magnetic resistance, the magnetic flux is not bound to a particular "medium" and is described by field sizes.

In particular, it can be provided that the system is designed such that the detection of the interlinked magnetic flux via the current is effected electrically. For this purpose, a corresponding electronic detection means may be provided.

The solenoid valve may be a switching solenoid valve with integrated core tube assembly.

The core tube assembly may include at least one armature guide tube, at least one magnetic core and at least one coated anchor.

The anchor may have a sealing element.

The coating of the armature can in particular take place in that the armature is coated with a material whose friction coefficient in the contact coating / armature guide tube is significantly lower than the coefficient of friction in contact of the exposed armature material with the armature guide tube.

The coating of the armature can be coated or formed in particular by means of polytetrafluoroethylene (PTFE).

The core tube assembly may further comprise at least one return spring and / or at least one damper element and / or at least one nozzle.

Further details and advantages of the invention will now be explained with reference to an embodiment shown in detail in the figures.

• 1 eine schematische Schnittdarstellung eines erfindungsgemäßen Systems zur Ermittlung des Verschleißes eines Magnetventils zur Durchführung des erfindungsgemäßen Verfahrens zur Ermittlung des Verschleißes des Magnetventils; und
• 2 eine beispielhafte Psi-I-Kurve.

Show it:

• 1 a schematic sectional view of a system according to the invention for determining the wear of a solenoid valve for carrying out the method according to the invention for determining the wear of the solenoid valve; and
• 2 an exemplary Psi-I curve.

1 shows a schematic sectional view of an inventive system 10 for determining the wear of a solenoid valve for carrying out the method according to the invention for determining the wear of the solenoid valve.

The system 10 has a solenoid valve 12 as well as a monitoring module 14 with appropriate monitoring unit 16 (eg comprising a suitable monitoring electronics and software) and evaluation electronics 18 (eg comprising a suitable evaluation electronics and software).

The monitoring module 14 serves as a test means by means of which it can be checked whether the measurement is below or above the threshold value for deviation from the Psi-I reference curve.

Next is a reference memory 19a and a setpoint memory 19b intended.

In the reference memory 19a At least one Psi-I reference curve is stored, which describes the chained magnetic flux over the current during the armature flight of an armature of the solenoid valve in the intact state.

In the setpoint memory 19b At least one threshold value for the deviation from the Psi-I reference curve is stored as an indicator for the accepted degree of wear.

At the solenoid valve 12 it is a switching solenoid valve with integrated core tube assembly 20 , as, for example, from the DE 10 2012 110 634 A1 is known.

The core tube assembly 20 consists of an armature guide tube 22 , a magnetic core 24 , an anchor partially coated with PTFE 26 with sealing element 28 , a return spring 30 a damping element 32 and a nozzle 34 ,

The PTFE coating is here by two ring-shaped PTFE sliding rings 36 educated. This is a possible embodiment.

In principle, other embodiments of a PTFE coating are conceivable and possible.

The PTFE seal rings 36 are arranged axially offset from one another.

In principle, instead of a PTFE coating, a coating can also take place with a material whose friction coefficient in the contact coating / armature guide tube is significantly lower than the coefficient of friction in the contact exposed anchor material / armature guide tube.

The solenoid valve 12 further includes a stationary coil unit 38 as well as a housing 40 on.

By means of the stationary coil unit 38 and the monitoring module 14 a measuring element is provided, by means of which at least one measurement of the chained magnetic flux via the current of the armature of the solenoid valve during operation of the solenoid valve is feasible.

The working connection of the solenoid valve 12 is with A and the supply terminal is designated P.

2 shows an example of a Psi-I curve of a solenoid valve.

The embodiment relates to the Psi-I characteristic of a system according to the invention for determining the wear of a solenoid valve, by means of which the inventive method for determining the wear of a solenoid valve can be performed.

By switching the solenoid valve rubs the armature on the wall of the armature guide tube, whereby abrasion of the armature surface, ie the PTFE layer, and the armature guide tube is formed.

Once the PTFE layer is worn and parts of the base material are exposed from the anchor, wear is known to increase significantly.

The inventive method and the inventive system 10 allow non-destructive detection of wear.

• Bei dem Verschleiß der Ankerbaugruppe wird die PTFE-Schicht auf dem Anker abgetragen.

This is based on the following principle:

• When the armature assembly is worn, the PTFE layer on the armature is removed.

As soon as the base material, in this case steel, is exposed, the material combination changes in frictional contact between armature and armature guide tube from PTFE / steel to steel / steel.

The material combination steel / steel has an approximately five times higher coefficient of friction than the material pairing PTFE / steel.

The higher coefficient of friction causes a higher resistance during anchor flight (i.e., the flight of the armature or the movement of the armature within the armature guide tube).

As a result, the ratio of distance traveled and the anchor flight time (= speed) is lower overall.

In addition, a correlation is observed between the bounce behavior of the armature on the damping elastomer and the wear of the PTFE layer of the armature. The weaker the degree of bouncing of the armature is, the higher the abrasion of the PTFE layer on the armature drops.

For the method according to the invention, the concatenated magnetic flux is measured via the current (equidistant time intervals) electrically by, inter alia, the coil unit 38 and the monitoring module 14 ,

The concatenated magnetic flux (interlinkage flux, induction flux or even coil flux) is the total magnetic flux of an inductance resulting from the integration of the magnetic flux density B over the area A _v formed by the coil together with its leads : $$\mathrm{\Psi \; =}{\displaystyle \underset{A_v}{\int }\overrightarrow{B}\cdot \text{d}{\overrightarrow{A}}_n}$$

der magnetische Fluss durch eine Windung bzw. die Querschnittsfläche des magnetischen Kerns ist.As the integration surface A _v , any oriented surface bounded by the short-circuited coil can be used. Because there are no magnetic monopole charges, the calculation of the flow depends exclusively on the boundary line, but not on the exact shape of the surface. In a conventional coil arrangement, the area of the magnetic field lines in the coil core is pierced N times when the field in the core is approximately homogeneous. It then follows: $$\mathrm{\Psi }\approx N\cdot {\mathrm{\Phi }}_{\text{w}}.\text{in which}{\mathrm{\Phi }}_{\text{w}}$$

is the magnetic flux through a turn or the cross-sectional area of the magnetic core.

Illustratively, the concatenated flux can be described in the following form: The induced voltage in one turn results from the change of the magnetic flux Φ _w enclosed by a single turn. If, as in the case of a coil, another winding is connected in series with the first one, an equally large induced voltage results also in this winding, as long as both windings comprise the same flux. Both induced voltages add up due to the series connection of the turns. With N windings for the entire coil, this results in an induced voltage proportional to the change of $$\mathrm{\Psi }=N\cdot {\mathrm{\Phi }}_{\text{w}},$$

This total voltage is applied to the terminals of the coil and thus the chained magnetic flux Ψ and not the simple magnetic flux Φ _w for the current-voltage relationship and the inductance of the coil is taken into account.

In the electro-technical literature, it has become widely accepted to refer to the magnetic flux in the magnetic core with Φ and the magnetic flux through the area spanned by the coil with Ψ. The choice of the different letter should not lead to the obvious misconception that the chained flow is a different physical quantity from the ordinary magnetic flux. Because the chained flow of a coil is physically nothing more than the usual magnetic flux, which results for the special case of a coil surface. However, the choice of the new letter is useful in distinguishing the coil flux from the magnetic flux that penetrates the cross-section of the coil core.

The measured data are recorded electrically, causing the solenoid valve 12 not damaged.

The curve recorded here is called the Psi-I curve (see 2 ).

The gradient of the Psi-I curve during the anchor flight is a measure of the anchor flight speed.

This gradient is determined by solenoid valves with an intact PTFE layer and serves as a setpoint.

This resulting curve with intact solenoid valves is in the memory element, here the reference memory 19a , the system 10 stored.

The scattering gives the tolerance limits.

Based on the analysis of worn solenoid valves, the corresponding threshold can be determined.

Bouncing affects the slope of the Psi-I curve at the anchor impact point. To determine the tolerance limits, boundary patterns are used.

In 2 is the example of a Psi-I curve of a solenoid valve of a system according to the invention for determining the wear of the solenoid valve 12 Shown with coated anchor surface.

Here, the slope (gradient) of the Psi-I curve represents the point 5 the described characteristic.

Once the PTFE layer of the anchor 26 is worn out, the amount of the gradient increases at the point 5 significantly.

If the gradient of the Psi-I curve is at the point 5 outside the scattering range of non-worn solenoid valves, so the wear on the armature or armature guide tube is present.

The bounce behavior is between point 6 and point 7 to observe.

The weaker the bounce, the lower the gradient of the Psi I curve between points 6 and point 7 ,

LIST OF REFERENCE NUMBERS

10

system

12

magnetic valve

14

monitoring module

16

monitoring unit

18

evaluation

19a

reference memory

19b

Setpoint memory

20

Core barrel assembly

22

Armature guide tube

24

magnetic core

26

anchor

28

sealing element

30

Return spring

32

damping element

34

jet

36

PTFE sliding ring

38

coil unit

40

casing

A

working port

P

supply terminal

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102012101634 A1 [0002]
• DE 102012110634 A1 [0032]

Claims (9)

Method for determining the wear of a coated-armature coated magnetic valve (12), comprising the following steps: - Detecting the interlinked magnetic flux over the current during the anchor flight of an armature (26) of the solenoid valve (12) in the intact state to establish a Psi-I reference curve; - Definition of at least one threshold for deviation from the Psi-I reference curve as an indicator of accepted degree of wear; - Measurement of the interlinked magnetic flux over the current during the anchor flight of the armature (26) of the solenoid valve (12) during operation of the solenoid valve (12); - Check whether the measurement is below or above the threshold deviation from the Psi-I reference curve. Method according to Claim 1 , characterized in that the detection of the concatenated magnetic flux via the electric current. A system (10) for determining the wear of a magnet valve (12) coated anchor surface with at least one reference memory (19a) having at least one Psi-I reference curve, the chained magnetic flux over the current during the armature flight of an armature of the solenoid valve in the intact state describes at least one setpoint memory (19b), in which at least one threshold value for deviation from the Psi-I reference curve is stored as an indicator of accepted degree of wear, at least one measuring element, by means of which at least one measurement of the chained magnetic flux via the current of the armature of Solenoid valve during operation of the solenoid valve is feasible, and at least one test means (14) by means of which it is verifiable whether the measurement is below or above the threshold for deviation from the Psi-I reference curve. System (10) after Claim 3 , characterized in that the detection of the concatenated magnetic flux via the electric current. System (10) after Claim 3 or Claim 4 , characterized in that the solenoid valve (12) is a switching solenoid valve (12) with integrated core tube assembly (20). System (10) according to one of Claims 3 to 5 , characterized in that the core tube assembly (20) comprises at least one armature guide tube (22), at least one magnetic core (24) and at least one coated armature (26). System (10) after Claim 6 , characterized in that the armature (26) has a sealing element (28). System (10) after Claim 6 or Claim 7 , characterized in that the armature (26) is coated with a material whose friction coefficient in the contact coating / armature guide tube is significantly lower than the coefficient of friction in contact of the exposed anchor material with the armature guide tube, in particular the armature is coated with polytetrafluoroethylene (PTFE) , System (10) according to one of Claims 6 to 8th , characterized in that the core tube assembly (20) further comprises at least one return spring (30) and / or at least one damper element (32) and / or at least one nozzle (34).

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