WO2019029879A1

WO2019029879A1 - Magnetic actuator for a conveying unit

Info

Publication number: WO2019029879A1
Application number: PCT/EP2018/066086
Authority: WO
Inventors: Peter Boehland
Original assignee: Robert Bosch Gmbh
Priority date: 2017-08-10
Filing date: 2018-06-18
Publication date: 2019-02-14
Also published as: DE102017213958A1

Abstract

The invention relates to a magnetic actuator (50) for a conveying unit (48), in particular a diaphragm pump for an operating medium/additive in a vehicle. The magnetic actuator (50) comprises an armature (64) which extends through a magnet coil (52) and acts on a diaphragm (56) which loads a working chamber (62) of the conveying unit (48). The armature (64) of the magnetic actuator (50) has a shoulder (70) which defines an armature step (72) and produces a drop of magnetic forces (24, 26) when the armature (64) approaches a mechanical stop (18).

Description

description

Magnetic actuator for a delivery unit Technical field

The invention relates to a magnetic actuator for a delivery unit, in particular for a diaphragm pump for an operating / auxiliary substance in a vehicle and to the use of the magnetic actuator.

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 a sealing seat of a valve or release. 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 to the stroke stop. By this measure, the

Noise development in the Rücksaugbetrieb the delivery unit can be significantly reduced. If the system line is to be completely sucked back, it will come to the end of the Rücksaugens when there is no more fluid to promote air. This results in a reduction of the hydraulic

Counter forces and the magnetic force acting on the armature in this case accelerates the armature so strong that the armature hits the stroke stop at a high speed. This causes a high noise emission.

Presentation of the invention

According to the invention, a magnetic actuator for a delivery unit, in particular a diaphragm pump for an operating / auxiliary substance in a vehicle

proposed, with an armature which extends through a magnetic coil and acts on a membrane which acts on a working space of the delivery unit. The armature of the magnetic actuator has a shoulder defining an armature stage which generates a drop in magnetic forces as the armature approaches its stroke stop.

Advantageously, an anchor design can be achieved by the proposed solution according to the invention, which generates a steeply sloping characteristic of the magnetic force of the magnetic actuator proposed according to the invention. With increasing counter-forces, for example one acting on the anchor

Spring force, the membrane force, hydraulic forces and frictional forces, which counteract the magnetic force, there is an intersection of the lines of force of each acting magnetic force and the just enumerated, the magnetic force opposite forces. Until this point of intersection, the anchor moves. The inventively proposed solution can for special

Operating situations, in particular in the Rücksaugmodus the delivery unit as well as the onset of air promotion a sufficient distance of the armature from the mechanical stroke stop of the delivery unit can be achieved, so that the noise emission can be significantly reduced and ideally even zero. In a further development of the magnetic actuator proposed according to the invention, the latter comprises a bottom part which has a peripheral notch on its outer circumference. Advantageously, this running on the outer circumference of the bottom part circumferential notch on the bottom part - seen in the stroke direction of the armature - at the same height as the heel of the anchor, which defines an anchor step on this and thereby generates a steeply sloping magnetic force characteristic.

The armature is traversed by a connecting part, on which the conveying of the operating / auxiliary substance-producing membrane is fixed. This is in particular an elastomeric membrane which can cooperate with supporting parts to avoid excessively large deformations.

At the connecting part which passes through the armature of the magnetic actuator proposed according to the invention, the membrane, in particular designed as an elastomeric membrane, is fastened with at least one undercut.

In a further development of the magnetic actuator according to the invention for the delivery unit, the membrane, which is preferably a

Elastomeric membrane acts, clamped in a valve plate. In the valve plate of the delivery unit, a working space is carried out, through which is promoted by the oscillating movement of the membrane operating / auxiliary material.

The armature executed, the anchor stage defining paragraph is used

According to the invention not only to produce a steep drop in the

Magnetic force characteristic in the magnetic force counteracting decreasing forces, but also to increase the magnetic force in the region of the initial air gap of the magnetic actuator. An effective there high magnetic force allows safe starting of the armature even at low currents. Low currents can occur when a low vehicle electrical system voltage in

Vehicle electrical system is present or the magnetic coil of the magnetic actuator has a relatively high temperature. The invention further relates to the use of the magnetic actuator in a diaphragm pump for conveying an operating / auxiliary substance,

in particular a urea-water solution in one

Exhaust after-treatment system for dosing into the exhaust gas tract of an internal combustion engine.

Advantages of the invention

By means of the magnetic actuator proposed according to the invention, a stroke-stop-free design of the same can be achieved, whereby both the noise in the suck-back mode and the noise emission when conveying air can be significantly reduced and ideally no

Noise emissions may arise. Due to the anchor design with a shoulder which defines an anchor step on the outer circumference of the armature, a steeply sloping magnetic force characteristic can be generated. With rising

Counter-forces such as a spring force acting on the anchor, the membrane force, hydraulic forces and frictional forces that counteract the magnetic force, the anchor moves from reaching one

Intersection of the lines of force no longer. By appropriate design of the armature or the paragraph on the outer circumference, a sufficient distance of the armature to the mechanical stroke stop can be ensured so that its achievement is not possible and thus no noise emissions can occur.

By achievable with the proposed solution according to the invention forming the magnetic force characteristic of the present invention proposed magnetic actuator such a large drop in magnetic force can be achieved that this is no longer sufficient, the armature against the magnetic force

to move counteracting opposing forces on the stroke stop, so that a stroke stop design can be achieved. Although the mechanical stroke stop is present, it is not reached.

Another advantage of the proposed solution according to the invention is that due to the steeply sloping magnetic force characteristic also in magnetic force fluctuations, such as by occurrence different currents, only small Hubwegänderungen. This is mainly due to the anchor stage on the outer circumference of the anchor

attributable to the paragraph. At the same time can by the

According to the invention proposed interpretation of the Magnetaktors be achieved that the magnetic force can be increased in the region of the initial air gap. An effective there high magnetic force allows safe starting of the armature even at low currents. Low currents can occur when there is a low vehicle electrical system voltage in the electrical system of the vehicle and the coil temperature is relatively high. Even when these two unfavorable operating parameters coincide, a safe starting of the armature due to the high magnetic force acting at the initial air gap is possible.

Short description of the drawing

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

described.

It shows:

Figure 1 shows a stationary design of a delivery unit with applied

Counter-forces that counteract a magnetic force and achievable strokes and intersections of the force lines and

2 shows a longitudinal section through a delivery unit with a

According to the invention proposed solenoid actuator.

O u rd e rs a n dia ria nte ns

FIG. 1 shows force profiles of magnetic forces as well as membrane pump forces acting in a membrane pump in the suck-back mode, in each case plotted over an armature stroke and

FIG. 2 shows the embodiment of a proposed invention

Magnet actuator for actuating a diaphragm pump designed as

Delivery unit. An inventive delivery unit 48 according to the sectional view in Figure 2 is in a gas aftertreatment system for

Internal combustion engines used. The denitrification of the exhaust gas of internal combustion engines is carried out by means of the SCR method, i. selective catalytic reduction. As an operating / auxiliary substance, which is conveyed through the delivery unit 48, a urea-water solution (AdBlue®) is used, which freezes below a temperature of -11 ° C. To protect the components of an exhaust aftertreatment system is therefore a

Rücksaugbetrieb the delivery unit 48 required in which still located in the system components of the exhaust aftertreatment system freezable urea-water solution sucked back, i. is sucked back into the storage tank for the operating / auxiliary material.

The illustration of Figure 1 are different force curves 10 too

Reference numeral 14 denotes an initial air gap, which is occupied by an armature 64 (see illustration according to FIG. 2) in the de-energized state. Reference numeral 16 denotes an air gap which remains between a mechanical stop 18 and the armature in the worst case.

In the illustration according to FIG. 1, reference numeral 20 denotes a course of pump forces which act in the delivery mode of the delivery unit 48. Reference numeral 22 designates the pumping forces acting within the delivery unit 48, which occur when conveying air within the delivery unit 48, i. if no operating / auxiliary material is promoted by the delivery unit 48, therefore, in the Rücksaugmodus to be emptied components of the exhaust aftertreatment system are free of operating / auxiliary and therefore only air is promoted.

The pump forces according to the courses 20 and 22 are composed of a spring force, a membrane force by the usually as

Elastomer membrane formed membrane is also exercised by acting within the delivery unit 48 hydraulic forces and friction forces. The enumerated forces counteract a magnetic force which is generated by a magnetic actuator 50 (cf. illustration according to FIG. 2).

In Figure 1, a curve 24 of a minimum magnetic force is entered, further a curve 26 of a maximum magnetic force. The magnetic force curves 24 and 26 have different Ankerhubwege result.

Thus, for example, with minimal magnetic force of the magnetic actuator 50, an armature stroke 28, which intersects the course 20 of the pump forces in the conveying operation of the delivery unit 48 at a first intersection point 30. This means that the armature 64 is stationary at the first intersection point 30, since the minimum magnetic force according to the course 24 and the pump forces acting in the conveying operation according to the course 20 in the first intersection 30 balance each other. With respect to the Ankerhubweg 12, the first intersection point 30 is farthest from the mechanical stop 18, consequently, no mechanical stop and consequently no noise emission arise.

According to the curve 26 of the maximum magnetic force, an armature stroke 32 sets, which leads together with the curve 26 of the maximum magnetic force to a second intersection 34. At the second intersection point 34, the maximum magnetic force holds according to the course 26 with the course 20 of the

Pump forces in the conveying operation the balance. Again, the first intersection point 30 is at a significant distance with respect to the mechanical stop 18, so that here, too, no impingement of the armature 64 impinges on the mechanical stop 18 and consequently a noise emission is omitted.

In the worst case, i. during course 24 self-adjusting pumping forces at conveying air in the delivery unit 48 is an anchor stroke 36 - maximum magnetic force provided - a third intersection 38 is reached at which the course 20 of the pump forces in the conveying operation of the delivery unit 48 and the Ankerhubweg 36 leading forces keep the balance. The most unfavorable third intersection 38 is still at a sufficient distance 40 to the mechanical stop 18, so that - maximum

Magnetic force presupposed - in air promotion no mechanical impact of the armature 64 on the mechanical stop 18 is omitted, ie the magnetic actuator 50 of the delivery unit 48 is thus designed so that the design allows a stroke stop operation of the delivery unit 48 in all, especially in the most unfavorable operating conditions. The stroke stop free

Design is made possible by the relatively steep gradients 24 and 26 at minimum magnetic force or at maximum magnetic force 26. In each case increasing opposing forces that counteracted the magnetic force according to the courses 24 and 26, it comes to the aforementioned and described above first intersection point 30, second intersection point 34 and the third intersection point 38. The movement of the armature 64 takes place only up to the said

Intersections 30, 34, and 38.

Figure 2 shows an embodiment of a magnetic actuator 50, which leads to the outlined in Figure 1 gradients 24 and 26 for a minimum magnetic force and a maximum magnetic force.

FIG. 2 shows that the delivery unit 48 comprises the magnetic actuator 50. The magnetic actuator 50 comprises a magnetic coil 52 which is surrounded by a coil holder 82. The magnetic actuator 50 further includes a bottom portion 66 which is movable with respect to an axis of symmetry 68 of the

Delivery unit 48 is shown only half, also a jacket 84 and a back plate 86. The bottom part 66 surrounds an armature 64. The armature 64 performs a lifting movement 60 according to the double arrow shown in Figure 2. The armature 64 is connected via a connecting part 58 with an elastomeric membrane 56.

This is clamped between the bottom part 66 and a valve plate 54.

Between the elastomer level 56 and the valve plate 54, a working space is acted upon. Through the working space 62 of promoting plant / excipient is promoted, which is a freezeable urea-water solution. In the illustration according to FIG. 2, the inflows and outflows into or out of the valve plate 54 are connected to the

associated valves for the operating / excipient to be promoted not shown. To promote the operating / auxiliary material leads the

Elastomeric membrane 56 an oscillating movement, whereby a Promotion of the operating / auxiliary materials through the working space 62 is made possible.

As is further apparent from the sectional view according to FIG. 2, the armature 64 is connected to the connecting part 58 along a contact surface 78.

The armature 64 includes a shoulder 70 that defines an armature stage 72 in the armature 64. The shoulder 70, which defines the armature stage 72, has a reduced diameter compared to the other diameter of the armature 64.

Furthermore, the magnetic actuator 50 proposed according to the invention is designed with respect to the bottom part 66 such that the bottom part has a notch 74 on its outer circumference 76. As is apparent from the sectional view of Figure 2, both the notch 74 on the outer circumference 76 of the bottom part and the anchor step 72 are approximately at the same height with respect to each other.

For the sake of completeness, it should be mentioned that the elastomer membrane 56 shown in half section in FIG. 2 is fastened in a form-fitting manner to the connecting part 58 by means of at least one undercut 80. By the connecting part 58, which is enclosed by the armature 64, an oscillating movement, namely the conveying movement is introduced into the elastomeric membrane 56. The elastomeric membrane 56 may be used to limit its deformation in the

Oscillation movement with supporting, for example, be provided sheet metal components, the deformation of the elastomeric membrane 56 in tight

Keep limits, which affects their lifetime favorable.

Due to the location and size of the notch 74 and the size of the heel 70, a high initial force can be modeled with a steep drop in magnetic force. The illustration according to FIG. 1 shows that in the region shortly after

Passage of leaving the initial air gap 14, the courses 24 and 26 of the magnetic forces assume their maximum. By the shoulder 70, not only a steep drop in the courses 24, 26 of the magnetic forces can be achieved in an advantageous manner, but also the magnetic force in the region of the initial air gap 14 can be greatly increased. This high force allows a safe start of the Ankers 64 even at low power. Low currents can under adverse operating conditions, such as low on-board voltage

On-board voltage network and a high temperature of the solenoid coil 52 occur.

In addition to increasing the courses 24, 26 of the magnetic forces of the maximum and minimum magnetic forces to their respective maximum, can be achieved by passage of their respective maximum by the design of the paragraph 70 of the illustrated in Figure 1 sharply falling courses 24, 26 of the magnetic forces. Due to the strong waste of the courses 24 of the minimum magnetic force and 26 at maximum magnetic force, the already discussed above in connection with Figure 1 intersections 30, 34, and 38 set. The strong decrease in the magnetic force according to the courses 24, 26 causes the armature 64 due to the opposing forces acting on this mechanical stop 18 even in the worst case with air promotion and maximum magnetic force corresponding to the Ankerhubweges 36 not achieved, but rather in this worst case the distance 40 to the mechanical stop 18 remains.

Due to the steeply sloping curves 24, 26 for the minimum magnetic force and the maximum magnetic force, resulting in magnetic force fluctuations, so for example at different currents only a small Hubwegänderung. Since the distance 40 in the worst case is still about 0.3 mm, it can be ensured even in the most unfavorable case and with strong fluctuations in the current that the armature 64 does not reach the mechanical stop 18 and consequently even in the most unfavorable operating conditions of the delivery unit 48 a Noise emission can be effectively avoided.

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 (50) for a delivery unit (48), in particular a

A diaphragm pump for an operating / auxiliary substance in a vehicle, having an armature (64) which extends through a magnet coil (52) and acts on a diaphragm (56), which has a working space (62) of the

Delivery unit (48) acted upon, characterized in that the armature (64) of the magnetic actuator (50) one an anchor stage (72)

defining paragraph (70) which generates a drop of magnetic forces (24, 26) when approaching the armature (64) to a mechanical stop (18).

2. Magnetic actuator (50) according to claim 1, characterized in that the shoulder (70) in the armature (64) increases the magnetic forces (24, 26) in the region of an initial air gap (14) and enables safe starting of the armature (64).

3. Magnetic actuator (50) according to claim 1, characterized in that the magnetic actuator (50) comprises a bottom part (66), which at its

Outer circumference (76) has a circumferential notch (74).

4. magnetic actuator (50) according to claim 3, characterized in that the notch (74) on the bottom part (66) seen in the stroke direction of the armature (64), approximately at the same height as the shoulder (70) of the armature (64). is provided.

5. magnetic actuator (50) according to claim 1, characterized in that the armature (64) is provided with a connecting part (58) which passes through the armature (64) in the axial direction and on which the membrane (56) is fixed.

6. magnetic actuator (50) according to claim 4, characterized in that the membrane (56) on the connecting part (58) with at least one

Undercut (80) is attached.

7. Magnetic actuator (50) according to claim 1, characterized in that the membrane (56) is clamped in a valve plate (54).

8. Magnetic actuator (50) according to claim 1, characterized in that the membrane (56) is an elastomeric membrane.

9. Use of the Magnetaktors (50) in a delivery unit (48) for promoting an operating / auxiliary material in one

Exhaust after-treatment system for dosing a urea-water solution in the exhaust gas tract of an internal combustion engine.