WO2010060687A1

WO2010060687A1 - Magnetic circuit

Info

Publication number: WO2010060687A1
Application number: PCT/EP2009/063594
Authority: WO
Inventors: Tilo Hofmann; Christof Ott
Original assignee: Robert Bosch Gmbh
Priority date: 2008-11-25
Filing date: 2009-10-16
Publication date: 2010-06-03
Also published as: DE102008044057A1

Abstract

The invention relates to a magnetic circuit (10) comprising a magnetic core (12), an armature (14) and a pole core (16). The magnetic circuit (10) produces a linear magnetic force via a current and/or via a travel path of the armature (14). At least one of the components (12, 14, 16) of the magnetic circuit (10) has protrusions (24, 34) distributed in the circumferential direction (38).

Description

description

Title magnetic circuit

State of the art

From DE 43 42 591 A1 electromagnetic pressure control valve is known. This pressure control valve has in its housing a movably guided valve spool, which is electromagnetically adjustable in position. A current control position of the valve spool is by a corresponding

Current supply of a solenoid continuously variable. For an application-oriented function of this pressure control valve high precision in the manufacture of the valve spool and its slide guide is required. Of this depend significantly on the tightness of the pressure control valve and its manufacturing costs. In addition, the valve spool requires a relatively high actuation force due to its relatively large, effective pressure surfaces.

DE 43 37 763 A1 discloses a designated as a pressure control valve, acting as a switching valve valve whose valve member is equipped with two seat valves. One of the valve members of the two seat valves is designed as a cone and therefore requires an accurate and expensive realizable concentric arrangement to its valve seat. This known valve can be brought into three defined switching positions and therefore is unable to produce any current flow to the solenoid dependent, continuous pressure control characteristic at the consumer.

EP 1 004 066 B1 relates to an electromagnetic pressure control valve with a magnetic part comprising at least one electrically controllable coil, a coil core and a displaceably guided armature. The electromagnetic pressure control valve comprises a valve member having an inlet, a return, a consumer connection and a cooperating with the armature

Valve element has. The valve member forms a first seat valve on a Closing member and a switched between the armature to the closing member actuator. The actuating member penetrates a control bore of the valve member and has a control edge, which is in operative connection with the control bore, a second seat valve.

Proportional magnets are characterized by the fact that they have an application-specific predetermined magnetic force map. Special features are that even at low currents a very high magnetic force is generated and the magnetic force is linear over the current and also over the stroke. The resulting magnetic force map is achieved by a special geometric design of the working air gap, also referred to as dipping. Typical designs are radially extending chamfers on pole cores and / or on anchors and / or diameter jumps. For currently manufactured components, this leads in sections to very thin-walled components with tight tolerances. The physical effect that is used is that in the thin-walled

Components of the material flow-dependent is driven into saturation and thus the magnetic flux is varied depending on the flooding depending on the course. The required components can only be produced by very cost intensive machining at high demands on the magnetic circuit.

Disclosure of the invention

While in the solution according to the prior art, the Kennfeldbeeinflussung is achieved by rotationally symmetric geometries are driven in the pole core by the magnetic flux into saturation, the proposed solution according to the invention, the material is no longer driven by rotationally symmetric geometries in the saturation, but in defined, thick walls circumferentially distributed around the circumference sections. As a result, the execution of thin-walled geometries, for the production of which very cost-intensive methods can be used, are substantially bypassed. The defined thick-walled sections of the invention which are distributed in the circumferential direction are designed in such a way that over a height coordinate (Z direction) the sections thick-walled projections with respect to their geometry correspond to the geometry of the steadily thinner-walled geometry. speaks for their production, however, as already mentioned, the cost-intensive manufacturing processes are used.

Due to the fact that according to the invention the sections are thick-walled and no thickness jump takes place in the axial direction, the geometries can be produced with relatively inexpensive production methods, for example by sintering, cold extrusion, stamping and rolling.

In a preferred embodiment variant, at a dipping stage of an electromagnetic pressure regulating valve, a material cross section varying in the direction of the armature stroke can be set by a course of the magnetic core, which is, for example, jagged. In this case, over a height H, a width b, a distance L and an angle α of the serrated geometry or a wave-shaped geometry, a characteristic influencing can be achieved. Also, the tines can be executed as waves in correspondingly variable geometries. Furthermore, as an alternative, the pole core can also be provided with tines or waves and, in addition, an influence on the characteristic can be achieved via the bevel position with respect to the circumferential angle of the tines or waves in the pole core or in the magnet core. These various design possibilities considerably increase the degree of freedom in dimensioning. However, it is also possible to represent a serration or wave geometry in the anchor and the magnetic core to run this, cylindrical.

The serrated or wave-shaped geometry described can be represented both by a rolled stamped part and by sintering or by cold extrusion or the like.

In further embodiments for the representation of characteristic-influencing geometries, the inventively produced components pole cores and magnetic core can be pulled over a sleeve made of an amagnetic material sleeve, which thus represents a pole tube to achieve a complete magnetic circuit geometry. This pole tube is a basic component of a magnetic circuit. Brief description of the drawings

Embodiments of the invention are illustrated in the drawings and explained in more detail in the following description.

It shows:

1 shows a half section through the components of a magnetic circuit, a

Polkerns, a centering sleeve, a magnetic core and an anchor,

FIG. 2 shows a development of the pole core with a serrated end face of the pole core;

3 shows a partially illustrated development of a pole core with a crown-shaped end face.

embodiments

The illustration according to FIG. 1 shows a half section through a magnetic circuit comprising an armature, a magnetic core, a centering sleeve and a pole core designed according to the invention.

A magnetic circuit 10 includes a magnetic core 12, an armature 14 and a pole core 16. In the illustration according to Figure 1, the armature 14 is received on the inside of a centering sleeve 18, while the components magnetic core 12 and pole core 16 are located on the outer circumferential surface of the centering sleeve 18 , The centering sleeve 18 is constructed symmetrically to its axis of symmetry 20, this also applies to the components magnetic core 12 and pole core 16 of the magnetic circuit 10 shown in half-section in Figure 1.

As can be seen from the illustration according to FIG. 1, there is a free space in the axial direction between the magnetic core 12 and the end face of the pole core 16 facing it. The free space is indicated by reference numeral 22. The free space 22 is bounded on the one hand by the lower, smooth-shaped end face of the magnetic core 12, and on the other hand by circumferentially spaced by recesses spaced projections 24 and 24 jaws limited. In half section according to FIG. 1, only one of the prongs 24 is shown in plan view. With reference numeral 24 is in half-section according to

Figure 1 denotes a flank of a projection or a prong. For the sake of clarity, the circumferentially extending, formed between the individual projections or prongs 24 recesses, not shown.

By the magnetic circuit 10, the components of which are shown schematically in half section as shown in Figure 1, a magnetic force is generated which is substantially linear over the current or over the stroke of the armature 14. In the solutions according to the prior art, the corresponding magnetic force characteristic is characterized by a special geometric design of the

Achieved working air gap. In this case, radially extending bevels on the magnetic core 12 and / or on the armature 14 and / or diameter jumps are made. This leads to sections of very thin-walled components, which must therefore be made very tight tolerances, which drives the production costs in the air. The partly very thin-walled components make use of the physical effect that the material in the thin-walled components is driven into saturation as a function of the flux, and thus the magnetic flux can be varied as a function of the flow as a function of the flow.

While in the known from the prior art solutions are used on costly to manufacture thin-walled components, rotationally symmetric geometries are driven in the magnetic core 12 by the magnetic flux into saturation, in the proposed solution according to the invention, the material is no longer rotationally symmetrical driven into saturation, but it 24 thick-walled material thicknesses are maintained in defined projections or prongs. These sections, be they projections 24, be they serrations 24, are arranged distributed in the circumferential direction and are designed in such a way that over a height coordinate z, cf. Reference numeral 28 is the sectionally thick-walled geometry, ie the circumferentially arranged projections 24 with recesses therebetween, which corresponds to the continuously thinning geometry according to the solution of the prior art. By the circumstance that the Projections or prongs 24 are thick-walled and no thickness jump occurs in the axial direction, these geometries can be produced with very low-cost manufacturing processes. As a cost-effective manufacturing processes are exemplary - but not exhaustive - the sintering, the cold extrusion, stamping and rolling called.

The illustration according to FIG. 2 shows a development of a magnetic core of the magnetic circuit proposed according to the invention as shown in FIG.

Although the formation and special geometry of projections 24 and / or serrations 24 will be described below with reference to the pole core 16, it is readily possible to attach other components of the magnetic circuit 10 with the serrated projections 24 and the serrations 24 at the end face facing the free space Mistake. Thus, instead of the pole core 16, the magnet core 12 or the armature 14 may also be provided with projections 24 or serrations 24 distributed in the circumferential direction 38 and spaced apart from each other by recesses 26.

The illustration according to FIG. 2 shows a development of the pole core 16. At the free space 22 zuweisenden end face, this has by recesses 26 mutually separate projections 24. The individual projections 24 are seen in the circumferential direction 38 spaced by recesses 26 of length L. With respect to the bottom of the recesses 26, the protrusions 24 pass over a height H in the axial direction 26 over the ground

Base surface of the recesses 26. Each of the projections 24 may be limited by a rising or falling edge, which may be performed at a helix angle α with respect to the horizontal.

A width of each of the protrusions 24 is indicated by reference letter B, where B denotes the width in the foot region of each of the protrusions 24.

As already mentioned in connection with the description of the magnetic circuit 10 according to the illustration in FIG. 1, the pole core 16, whose development 30 is illustrated in FIG. 2, is symmetrical here with respect to the axis of symmetry 20 executed. Neither the development of the pole core 16 nor the pole core 16 itself must be symmetrical with respect to the symmetry axis.

Due to the formation of projections 24, which are separated by extending in the circumferential direction 38 recess 26 from each other, is in the direction of

Ankerhubes the armature 14 varying material cross section through the jagged course at the free space 22 zuweisenden end face of the pole core 16 set. The height H, the width B of the projections 24, the length L of the recess 26 and the helix angle α of the projections or serrations 24 can be varied correspondingly to influence the characteristic of the magnetic field. Also, the projections or serrations 24 may be embodied as shafts with corresponding variable geometries instead of serrations.

This contouring can be formed both on the magnetic core 12 in projections or prongs 24 or in waveform and additionally be carried out on the chamfer position with respect to the circumferential angle of the prongs or projections 24 or the waves in the magnetic core 12 and pole core 16 for influencing the characteristic. This results in a significantly increased degree of freedom with respect to the design of the magnetic circuit 10 proposed according to the invention as shown in FIG. 1.

As already mentioned above, it is also possible to form the projections or serrations 24 or the wave geometry in the armature 14 and to make the pole core 16 cylindrical. The magnetic circuit 10 comprises the centering sleeve 18, within which the armature 14 is arranged to be movable in the vertical direction and on the outer circumferential surface of which the magnetic core 12 and the pole core 16 are located, forming the free space 22.

The above-described geometries, be they in the form of edged projections 24 or serrations 24, can be produced by rolled stampings or by sintering or cold extrusion. A design guideline for shaping the protrusions 24 and the prongs 24, respectively, is to minimize L, for example by defining the transition radius between two adjacent prongs 24. A helix angle α is preferably in the range between 15 ° <α <45 °. The illustration according to FIG. 3 shows a further possible embodiment of the magnetic circuit proposed according to the invention.

As an alternative to the straight flanks shown in FIG. 2, rising and falling flanks having projections or serrations 24, crown-shaped projections 34 are formed on one end face of the pole core 16 in the embodiment according to FIG. Each of the protrusions of a crown-shaped structure 34 is shaped in mushroom shape 40. The protrusions in mushroom form 40 are each separated from each other by recesses 26, analogous to the rising flanks or falling flanks having projections 24 in the helix angle α according to the embodiment in Figure 2.

Due to the mushroom-shaped structure 40 of the individual projections, undercuts 24 result between the recesses 26 and the maximum lateral

Extension of the individual mushroom-shaped 40 formed crown-shaped projections 34 as shown in Figure 3. Analogous to the embodiment according to FIG. 2, the individual mushroom-shaped crown-shaped projections 34 are separated from each other by the recesses 26. This results in the sequence of crown-shaped projections 34 alternating in circumferential direction 38, which in FIG

Mushroom mold 40 are formed, each followed by a recess 26.

In addition to the trapezoidal geometry of the protrusions or serrations 24 shown in FIG. 2, the mushroom-shaped protrusions 34 shown in FIG. 3, other geometries can also be formed on the pole core 16 or on the magnetic core 12 or also on the armature 14 which a no longer rotationally symmetric saturation but a saturation of the material in defined thick-walled in the circumferential direction 38 arranged projections 24 and 34 can be carried out. It is important that the thick-walled projections 24, 34 are designed such that over the height coordinate z, see. Reference numeral 28, the partially thick-walled geometry of the projections 24, 34 of that geometry of steadily thinning geometry, however, which entails high manufacturing costs, corresponds.

Claims

claims

First magnetic circuit (10) having a magnetic core (12), an armature (14) and a pole core (16) for representing a linear and a linear magnetic force, characterized in that at least one of the components of the magnetic circuit (10), the magnetic core (12), the

Anchor (14) or the pole core (16) in the circumferential direction (38) distributed projections (24. 34).

2. magnetic circuit (10) according to claim 1, characterized in that the magnetic core (12) and the pole core (16) are accommodated on a centering sleeve (18).

3. magnetic circuit (10) according to claim 2, characterized in that the magnetic core (12) and the pole core (16) are arranged to form a free space extending in the axial direction (22).

4. magnetic circuit (10) according to claim 1, characterized in that the projections (24, 34) on the magnetic core (12), the armature (14) or on the PoI- core (16) without a in the axial direction (36) extending change of Material thickness are executed.

5. magnetic circuit (10) according to claim 4, characterized in that the projections (24, 34) are designed such that depending on a height coordinate z (28) the wall thickness of circumferentially distributed (38) arranged thick-walled projections (24 , 34) the wall thickness of a in

Axial direction (38) steadily tapering geometry.

6. magnetic circuit (10) according to claim 1, characterized in that the projections (24, 34), seen in the circumferential direction (38) alternately to the recess (26) in a length L are executed, have a width B and over the Recess (26) protrude with a height H.

7. magnetic circuit (10) according to claim 1, characterized in that the projections (24) or prongs (24) are limited by flanks which extend in a helix angle α with respect to the horizontal.

8. magnetic circuit (10) according to claim 1, characterized in that the projections are designed as a crown-shaped projections (34) and each in mushroom shape (40) are designed.

9. magnetic circuit (10) according to claim 8, characterized in that the

Protruding projections (34) in mushroom form (40) each recesses (26) and with respect to these have an undercut (42).

10. magnetic circuit (10) according to claim 1, characterized in that the projections (24) and the recesses (26) extend in the circumferential direction (38) seen in waveform.

1 1. A method for producing a magnetic circuit (10), a magnetic core (12), an armature (14) and a pole core (16) comprising, according to one or more of the preceding claims, characterized in that in the circumferential direction (38) distributed arranged thick-walled projections (24, 34) having components of the magnetic circuit (10), magnetic core (12), armature (14) and pole core (16) by sintering or cold extrusion or punching or rolling are made.