WO2019076535A1

WO2019076535A1 - Magnetic actuator for a conveying unit

Info

Publication number: WO2019076535A1
Application number: PCT/EP2018/074292
Authority: WO
Inventors: Peter Boehland; Christoph Waletzek
Original assignee: Robert Bosch Gmbh
Priority date: 2017-10-16
Filing date: 2018-09-10
Publication date: 2019-04-25
Also published as: DE102017218452A1

Abstract

The invention relates to a magnetic actuator (12) for a conveying unit (10), in particular a membrane pump for conveying an operating/auxiliary material in a vehicle, having an immersion armature (22), which extends through an internal pole (20) and actuates an elastomer membrane (46), which in turn actuates a valve group. The immersion armature (22) is acted upon by a compression spring (30), which presses the elastomer membrane (46) to a sealing seat (56) of a valve plate (50) of the conveying unit (10). When passing an armature stroke path (82), the immersion armature (22) reaches a resting point (98), which is at a safety distance (94) from a travel stop (92) of the immersion armature (22), wherein the magnetic force acting on the immersion armature (22), on the one hand, and the force of the compression spring (30) and hydraulic forces acting on the immersion armature (22), on the other, are in equilibrium at the resting point (98) on the magnetic force characteristic curve (88).

Description

description

Magnetic actuator for a delivery unit Technical field

The invention relates to a magnetic actuator for a delivery unit, in particular for the promotion of an operating / auxiliary substance for dosing in an exhaust aftertreatment system of an internal combustion engine and the use of the magnetic actuator in the delivery unit.

State of the art

DE 10 2015 226 463 AI refers to a magnetic actuator for a

Delivery unit. In the delivery unit is in particular a diaphragm pump, which is used to promote an operating / auxiliary material in a

Vehicle is used. This includes a spring-loaded armature which extends through a magnetic coil and acts on a membrane. This can either act on a working space of the delivery unit and / or cover or release a sealing seat of a valve. The membrane is connected to the actuator via an intermediate layer.

WO 2013/029849 AI relates to a dosing system for a liquid

Reducing agent. It is proposed a metering module for injecting liquid urea-water solution in the exhaust gas of an internal combustion engine, which consists of two pumps, namely a feed pump and a

Ventilation pump exists. As a result, on the one hand the injection of urea-water solution is possible and on the other hand is also a safe and

Reliable venting of the system possible when the internal combustion engine is to be switched off. By a reduced increase in magnetic force with decreasing

magnetic main air gap, the impact speed of the armature can be reduced at the stroke stop. By this measure, the

Noise development in the Rücksaugbetrieb the delivery unit can be significantly reduced. When the system line is to be completely sucked back, at the end of the back suction, when there is no more fluid, air is supplied. This results in a reduction of the forces acting on the armature counter forces, that of the armature actuating magnetic force

counteract, the anchor is therefore accelerated so that it meets with a relatively high speed on the stroke stop. This causes an undesirable noise emission.

In today's pumping units Rücksaugpumpen be used to the reduction medium at standstill of the vehicle from the lines

suck back to avoid damage due to ice pressure occurring at the metering module of the exhaust aftertreatment system or on the line. Currently used return pumps are designed so that they suck back only a subset of the operating / auxiliary material. Furthermore, the mechanical stop of the armature is a disruptive factor, noise emission can be reduced by a relatively high additional pairing costs in the production.

DESCRIPTION OF THE INVENTION According to the invention, a magnetic actuator for a delivery unit, in particular a membrane pump for conveying an operating / auxiliary substance in one

Vehicle proposed, with an anchor which extends through an inner pole and actuates an elastomeric membrane which controls a valve group. The anchor is designed as a plunger anchor, which reaches a rest point at the passage of an Ankerhubweges, at a safety distance of one

Stroke stop of the plunger anchor is.

The design of the armature as a plunger armature offers the advantage that by means of a plunger armature a declining magnetic force can be represented over the stroke of the armature. The advantage is that in addition to the relatively large stroke of the Dive anchor also the impact energy of the anchor compared to

Use of a flat anchor can be greatly reduced. At a

Flat anchor increases the generated magnetic force with decreasing working air gap. In a plunger anchor, however, the force remains approximately the same and can be designed according to the invention so that the magnetic force acting on the armature decreases with increasing Ankerhubweg.

In a further development of the magnetic actuator proposed according to the invention, the plunger armature passes through a stroke region between the sealing seat and a remaining residual air gap.

The inventively proposed magnetic actuator has a

Magnetic force characteristic, which includes a sloping region in which the magnetic force decreases, wherein the falling portion of the magnetic force characteristic terminates in a rest point. In this rest point on the magnetic force characteristic, the magnetic force acting on the plunger armature of the magnetic actuator, on the one hand, and the counteracting forces of the compression spring and hydraulic forces acting on the diver armature, on the other hand, are in equilibrium. At rest, the plunger anchor no longer moves due to the balance of forces.

The magnetic actuator is designed so that when reaching the rest point on the magnetic force characteristic, the achievement of a residual air gap is ensured. When the residual air gap through the plunger armature is reached, a safety distance remains between the plunger rod and a mechanical stroke stop. This means that the plunger, after resting on the

Magnetic force characteristic with respect to its stroke, i. has reached the residual air gap, no longer moves and therefore a mechanical stop on the mechanical stroke stop is omitted, whereby a noise emission is excluded.

The invention also relates to the use of the magnetic actuator in a delivery unit, in particular for the promotion of an operating / auxiliary substance such as a urea-water solution in one

Exhaust after-treatment system for an internal combustion engine. Advantages of the invention

The advantages of the inventively proposed embodiment of the

Magnetic armature, in particular the design of the armature as a plunger anchor are that when a decrease in the armature acting counter forces, and the magnetic force acting on the plunger anchor decreases. The beating advantage of the plunger anchor principle is that in addition to a high achievable stroke and the impact energy in comparison to the use of a

Flat armature magnets can be reduced. This is reflected in a decreasing course of the magnetic force characteristic along the Ankerhubweges, starting from the working air gap to the residual air gap. When the residual air gap is reached, the armature no longer moves, because at a rest point from the magnetic force characteristic curve, the opposing forces acting on the diver and the reduced magnetic force are in equilibrium. Upon reaching the

Remaining air gap, the anchor keeps a safe distance to his

mechanical stroke stop so that no impact occurs, whereby a noise emission is excluded. This means that the delivery unit equipped with the magnet armature proposed according to the invention operates very quietly in the return suction mode and during operation.

Another advantage of the proposed solution according to the invention lies in the low speed in the execution of an armature stroke, due to the falling magnetic force characteristic and thereby produces a smaller

Frictional heat in the tribology system.

Short description of the drawing

With reference to the drawing, the invention will be discussed in more detail below

described.

It shows:

Figure 1 is a sectional view of the magnetic actuator of a delivery unit and Figure 2 shows the course of the magnetic force according to a

Magnetic force characteristic, plotted over the Ankerhubweg. variants

The illustration according to FIG. 1 shows a section through a magnetic actuator 12 proposed according to the invention for a delivery unit 10.

The magnetic actuator 12 comprises a magnetic coil 14, which is enclosed by a jacket 16. Above the magnetic coil 14 is a

Rear plate 18. The magnetic coil 14 is received at an inner pole 20 of the magnetic actuator 12. In the inner pole 20 of the magnet actuator 12, a plunger 22 is a lifting movement 26 executing out. The plunger armature 22 comprises at one end a plunger anchor stage 24. The plunger anchor 22 is connected to a plastic part 28, which is embodied essentially in the form of a pin. The plunger armature 22 is acted upon by a compression spring 30, which is guided in the inner pole 20. The compression spring 30 is supported on a disc 32 on the upper side of the plunger anchor 22.

The plunger anchor 24 at the top of the plunger armature 22 is defined by a first plunger diameter 34 and a second anchor diameter 36. An electrical contacting of the magnetic coil 14 of the magnetic actuator 12 is effected by an electrical contact 38 on one side

Pump housing 54 of the delivery unit 10th

From the sectional view of Figure 1 also shows that the plunger armature 22 and the plastic part 28 are connected to a contact surface 42 with each other. According to the lifting movement 26 of the plunger armature 22, the plastic part 28 moves at the lower end of a

Elastomeric membrane 46 is added. The elastomeric membrane 46 is joined by means of at least one undercut 48 to a plate-shaped projection of the plastic part 28. The elastomeric membrane 46 is moved in accordance with the oscillating stroke 26 of the plunger armature 22 and actuates valves provided in a valve plate 50, namely a suction valve 51 and a Pressure valve 52. The pressure valve 52 is disposed in a channel 60 to the storage tank, in which the operating / auxiliary material is stored. In the de-energized state of the magnetic actuator 12 shown in Figure 1, the compression spring 30 presses the elastomeric membrane 46 on a sealing seat 56 which is arranged centrally in the valve plate 50. The fluid to be delivered, namely the operating / auxiliary material, is conveyed through a working space 58 by the oscillating stroke movement 26 of the elastomeric membrane 46, generated by the plunger anchor 22.

In Rücksaugmodus the delivery unit 10 as shown in Figure 1 is a sucking back of the freezing operating / auxiliary material from others

Components of a vehicle provided

Exhaust aftertreatment system. The operating / auxiliary substance is a urea-water solution (AdBlue®), which freezes below an outside temperature of 11 ° C. In the Rücksaugmodus line components and module components of the exhaust aftertreatment system are sucked to empty

Ice pressure damage to avoid the above components.

Furthermore, the illustration according to FIG. 1 shows a recessed notch 40 on the outer circumference of the inner pole 20. The recirculating notch 40 is located approximately at the same height as the plunger anchorage 24, which by the two different diameter, namely the first

Anchor diameter 34 and the second anchor diameter 36 is defined.

Reference numeral 54 denotes a pump housing of the delivery unit 10, which is only partially shown in the sectional view of Figure 1 and in which the magnetic actuator 12 is received. The

Pump housing 54 is closed by a cover 44.

FIG. 2 shows magnetic force profiles 80, which are plotted via an armature stroke 82.

Reference numeral 96 represents a conventional magnetic force profile when using a magnet, for example a flat armature magnet according to the prior art. As can be seen from the illustration according to FIG. 2, the magnetic force increases corresponding to the conventional magnetic force profile 96 when a component of the magnetic circuit, ie the armature, moves from the starting air gap 84 in the direction of the residual air gap 86. at

decreasing counterforces acting on the anchor exceed the

Magnetic force according to the conventional magnetic force profile 96 the

Counter forces, so that it can come to a stop of the armature on the stroke stop 92.

However, if a plunger anchor 22, as shown and described in connection with FIG. 1, is used, a magnetic force characteristic curve 88 can be achieved which comprises a sloping region 90. Starting from the

Initial air gap 84, in which a Loslaufen the plunger armature 22 from the

Sealing seat 56 is carried out, the magnetic force corresponding to the magnetic force characteristic 88 decreases in the direction of the residual air gap 86 from. At a rest point 98 on the magnetic force characteristic curve 88, the magnetic force acting on the plunger armature 22 is counteracted by the opposing forces acting on it, for example hydraulic

Counter forces, in equilibrium, so that the plunger anchor 22 stops at rest 98. The rest point 98 on the magnetic force characteristic curve 88 coincides with the reaching of the residual air gap 86. Starting from the rest point 98 and the residual air gap 86, the plunger armature assumes the safety distance 94 with respect to the mechanical stroke stop 92 of the plunger anchor 22. Since the

Immersion anchor 22 has come to a halt after reaching the rest point 98, and a safety distance 94 to the mechanical stroke stop 92 of

Diving anchor 22 is met, is reaching the mechanical

Hubanschlages 92 excluded during the movement of the plunger anchor 22. There is no metallic contact between the plunger armature 22 on the one hand and the mechanical stroke stop 92 on the other hand, so that no

Noise emission can occur.

When using the Tauchankerprinzips, it is advantageous that in addition to a relatively high lift in the stroke range 26, see the stroke range 100 in Figure 2, im

Compared to flat armature magnets a greatly reduced impact energy can be achieved. In a flat anchor, the magnetic force increases with decreasing working air gap, compare the conventional

Magnetic force curve 96 in the illustration of Figure 2. In the

According to the invention proposed solution and the use of Tauchankerprinzipes the magnetic force remains approximately the same and is designed so that the magnetic force characteristic has a sloping region 90, the magnetic force decreases with increasing Ankerhubweg 82. The interaction of the recirculating notch 40 on the outer circumferential surface of the

Bottom part 20 with the plunger-type armature 24 on the plunger armature 22 has the effect that according to the magnetic force characteristic curve 88 entered in FIG. 2, it has a sloping region 90. The invention is not limited to the embodiments described herein and the aspects highlighted therein. Rather, within the scope given by the claims a variety of modifications are possible, which are within the scope of expert action.

Claims

claims

1. magnetic actuator (12) for a delivery unit (10), in particular a

A diaphragm pump for conveying an operating / auxiliary substance in a vehicle, having a plunger anchor (22) which extends through an inner pole (20) and actuates an elastomeric membrane (46), which in turn actuates a valve group, characterized in that

Immersion anchor (22) on passage of Ankerhubweges (82) a

Resting point (98) reached, which is located at a safety distance (94) from a stroke stop (92) of the plunger (22).

2. Magnet actuator (12) according to claim 1, characterized in that the plunger armature (22) by a compression spring (30) is acted upon, the elastomeric membrane (46) on a sealing seat (56) of a valve plate (50) of the delivery unit (10). suppressed.

3. Magnetic actuator (12) according to claim 2, characterized in that at rest (98) on the magnetic force characteristic (88) on the

Solenoid armature (22) acting magnetic force on the one hand and on the plunger armature (22) acting force of the compression spring (30) and hydraulic forces on the other hand are in equilibrium.

4. magnetic actuator (12) according to claim 1, characterized in that a stroke range (100) of the plunger armature (22) between the sealing seat (56) and a remaining residual air gap (86).

5. magnetic actuator (12) according to claims 1 and 2, characterized

characterized in that a magnetic force characteristic (88) of the magnetic actuator (12) comprises a sloping region (90) terminating in a rest point (98).

6. Magnet actuator (12) according to claim 1, characterized in that reaching the rest point (98) with the achievement of a

Residual air gap (86) during the passage of Ankerhubweges (82) coincides.

7. magnetic actuator (12) according to claim 1, characterized in that on reaching the residual air gap (86) by the plunger armature (22) between this and a mechanical stroke stop (92)

Safety distance (94) remains.

8. Use of the magnetic actuator (12) according to one of claims 1 to 7 in a delivery unit (10) for promoting an operating / auxiliary substance in an exhaust aftertreatment system of a

Internal combustion engine.