EP0170894B1 - Electromagnetic driving device - Google Patents

Description

The invention is in the field of electromagnetically operated switches and is to be applied to a drive arrangement which, in order to trigger a mechanical switching operation, has a permanent magnet which is movably arranged between two magnetic poles and is connected to an actuating element.

In a known electromagnetic drive arrangement (GB-A1-2 104 730), which is provided for actuating the door locks of a motor vehicle, the two magnetic poles, between which the permanent magnet is arranged movably, are arranged at a fixed distance from one another which limits the freedom of movement of the permanent magnet. The two magnetic poles are connected by a yoke and can be electrically excited with the same name by means of an excitation coil consisting of two identical coil halves. A third magnetic pole is arranged in the middle between the two magnetic poles and at the same time laterally outside the clear space between the two magnetic poles, which is connected to the yoke and can be excited with the same name compared to the first two magnetic poles by the two coil halves of the excitation coil being on both sides of the connection point of the third magnetic poles are arranged with the yoke and are excitable in opposite directions. In this known drive arrangement, the permanent magnet is provided on the two sides facing the first two magnetic poles, each with a plate made of ferromagnetic material; The permanent magnet and the plates together have a thickness that is substantially greater than the sum of half the distance between the first two magnetic poles and half the width of the third magnetic pole in the direction of adjustment of the permanent magnet. This configuration of the drive arrangement achieves a high acceleration of the permanent magnet which is self-retaining in the two end positions in the initial phase of the movement.

In another known electromagnetic drive arrangement (DE-A-1 614 350) the permanent magnet holds itself in the two switching positions. No special plates made of ferromagnetic material are provided on the two end faces of the permanent magnet and the permanent magnet has an overall length that is shorter than is half the distance between the two outer magnetic poles.

On the basis of an electromagnetic drive arrangement with the features of the preamble of claim 1, the invention is based on the object of designing the drive arrangement in such a way that fluid flows can be controlled with the actuating element of the permanent magnet and that the permanent magnet and the actuating element connected to it certainly have the desired switching position reached and remains in this switching position with high holding force without the excitation having to be maintained after reaching this switching position.

• dass die Dicke des Dauermagneten grösser ist als die Breite, die der dritte Magnetpol in Verstellrichtung des Dauermagneten aufweist,
• dass die Dicke jeder an dem Dauermagneten angeordneten Platte höchstens gleich derjenigen Breite ist, die der dritte Magnetpol in Verstellrichtung des Dauermagneten aufweist, und
• dass in den beiden Endlagen des Dauermagneten der Überstand einer Platte über die entsprechende Aussenkante des dritten Magnetpols höchstens 75% der Dicke dieser Platte beträgt.

To achieve this object, according to the invention it is provided that the actuating element connected to the permanent magnet is provided with at least one control element for opening and closing a control opening guiding a fluid.

• that the thickness of the permanent magnet is greater than the width which the third magnetic pole has in the adjustment direction of the permanent magnet,
• that the thickness of each plate arranged on the permanent magnet is at most equal to that width which the third magnetic pole has in the direction of adjustment of the permanent magnet, and
• that in the two end positions of the permanent magnet, the protrusion of a plate over the corresponding outer edge of the third magnetic pole is at most 75% of the thickness of this plate.

Such a configuration of the drive arrangement ensures, with a high magnetic holding force, that the permanent magnet bears tightly against the respective magnetic pole and thus reliably opens or closes the control opening to be actuated by the control element. The rich concern is among other things caused by the specially dimensioned plates made of ferromagnetic material, which conduct the magnetic flux to the third magnetic pole. Furthermore, the selected arrangement ensures that if the control pulse acts too shortly on the excitation coil, the permanent magnet does not get stuck in a central position in front of the third magnetic pole, but - even with faulty pulses - is safely pulled into one of the two end positions. In particular, the slight protrusion of the magnetic plates over the outer edge of the third magnetic pole further ensures that a sufficient tightening force is effective when the permanent magnet is switched from one end position to the other.

With regard to the control of fluid flows, a constructive embodiment of the new drive arrangement consists in that the two magnetic poles and the yoke connecting them have the shape of a C, the third magnetic pole being arranged with its free end pointing towards the opening of the C and the permanent magnet on the one end of a spring tongue is fastened, which is firmly clamped or pivotably mounted with its other end and on which the control element or elements are arranged. In such an embodiment, the control elements can interact with corresponding counter elements of a device to be controlled. The spring tongue is used on the one hand for the movable mounting of the permanent magnet and on the other hand for coupling the control elements to the permanent magnet. In a further development of this arrangement, it is expedient to arrange the spring tongue with the permanent magnet in a housing which has the control openings and is coupled to the magnetic poles. This is an easy to assemble construction unit available. - A drive arrangement designed in this way can be used in particular to control heating or ventilation flaps in motor vehicles if the control openings are designed as nozzle openings connected to a vacuum control device and the control elements are designed as seals arranged on the spring tongue. The lossless switch end positions of the magnet arrangement are particularly advantageous for such control purposes.

Another embodiment of the new drive arrangement makes it possible to couple the control element (s) directly to the adjustable permanent magnet. For this purpose, the first two magnetic poles are designed as hollow tubes and are located concentrically in openings in the axially spaced-apart coil halves of the excitation coil; the yoke consists of a cylindrical yoke sheath that surrounds the coil halves and two cover plates that carry the hollow mandrels and are attached to both ends of the yoke sheath. A ring is inserted as the third magnetic pole between the two hollow mandrels, the outer edge of which rests on the yoke sheath. This arrangement is perfected in that the actuating element consists of a plunger arranged on at least one side of the permanent magnet and passing through a hollow tube, the free end of which is conical. - A compact design of this drive arrangement is given when the free end of the plunger is surrounded by a plastic part provided with a longitudinal bore, which is inserted by means of a pipe socket surrounding the plunger in a clamping manner in one of the hollow tubes, and when the plastic part has a first control opening and one has a second control opening, the first control opening for receiving the free end of the plunger being provided with a corresponding conical contrast.

• Fig. 1 eine Antriebsanordnung, bei der ein Gehäuse, das eine den Dauermagneten tragende Federzunge enthält, an die Magnetpole angekoppelt ist.
• Fig. 2 zeigt eine Antriebsanordnung, bei der die Magnetpole als Hohlrohre ausgebildet sind und bei der ein die Steueröffnungen enthaltendes Kunststoffteil auf einen Magnetpol aufgesteckt ist.

The subject matter of the invention is described in more detail below with reference to two exemplary embodiments shown in the drawing. It shows

• Fig. 1 shows a drive arrangement in which a housing which contains a spring tongue carrying the permanent magnet is coupled to the magnetic poles.
• Fig. 2 shows a drive arrangement in which the magnetic poles are designed as hollow tubes and in which a plastic part containing the control openings is attached to a magnetic pole.

Fig. 1: 1 and 2 denote two opposite magnetic poles, which are connected to each other via a yoke 3. The magnetic poles 1 and 2 together with the yoke in the form of a C. In the middle of the yoke 3 there is a third magnetic pole 4 connected to it. With its free end 5, the third magnetic pole 4 projects toward the opening existing between the two magnetic poles 1 and 2. An excitation coil consisting of two identical coil halves 6 and 7 is provided to excite the magnetic poles 1, 2 and 4. A coil half 6 is arranged on one side and a coil half 7 on the other side of the junction of the third magnetic pole 4 with the yoke 3 in the return circuit of the two magnetic poles 1 and 2. The two coil halves 6 and 7 are simultaneously connected to voltage and are switched or wound in such a way that they excite the yoke 3 in opposite directions. In this way, the two opposite magnetic poles 1 and 2 are always magnetized with the same name and the third magnetic pole 4 is magnetized opposite to these two magnetic poles 1 and 2.

An airtight housing 8 made of non-magnetic material is clamped to the two opposite magnetic poles 1 and 2. A spring tongue 9 is arranged in the housing 8. On the one end 9a projecting between the opposite magnetic poles 1 and 2, a permanent magnet 10 is fastened, which is guided to be movable by the spring tongue 9 in the direction of the two magnetic poles 1 and 2. With its other end 9b, the spring tongue 9 is firmly clamped in the housing 8 or held rotatably between the poles. The two sides of the permanent magnet 10 lying in the adjustment direction are covered flush with plates 11 and 12 made of ferromagnetic material. The arrangement of the permanent magnet 10 covered with the plates 11 and 12 on the spring tongue 9 is such that there is an air gap 13 between the side of the permanent magnet 10 facing the third magnetic pole 4 and the third magnetic pole 4. This air gap can be filled by the material of the housing 8. There is a small distance between the permanent magnet 10 and the relevant housing wall, so that the adjustment of the permanent magnet 10 is not hindered.

On the housing 8, three connecting pieces 14, 15 and 16 are formed, which are provided with nozzle openings 18, 19 and 20 opening into the housing cavity 17. Two connecting pieces 15 and 16 are arranged opposite one another on the housing 8, so that their nozzle openings 19 and 20 also open into the housing cavity 17 opposite one another. In the area of these mouths, a seal 21 is attached to the spring tongue 9, which, depending on the position of the permanent magnet 10, rests on the mouth of one or the other nozzle opening 19 or 20 and is pressed sealingly onto this mouth by the holding force of the permanent magnet 10.

1 operates as follows: It is assumed that the pole of the permanent magnet 10 which is in contact with the magnetic pole 2 is a south pole and the pole of the permanent magnet 10 which is adjacent to the third magnetic pole 4 is a north pole and that the coil halves 6 and 7 are not connected to voltage .

In this state, the magnetic flux of the permanent magnet 10 passes through the plate 11, which acts as a flux concentrator in the third magnetic pole 4 and closes via the yoke 3, the magnetic pole 2 and the plate 12 to the south pole of the permanent magnet 10. This flux exerts a holding force on the permanent magnet 10 which presses it against the magnetic pole 2. As the illustration in FIG. 1 shows, the package consisting of the plates 11 and 12 and the permanent magnet 10 projects somewhat beyond the upper edge of the third magnetic pole 4. As a result of the projection of the plate 11 over the edge of the third magnetic pole 4, part of the magnetic occurs Flow obliquely down into the third magnetic pole 4. This results in a force component directed vertically downwards, which contributes to an increase in the holding force. If the permanent magnet 10 is in its other end position, then the plate 12 projects beyond the lower edge of the third magnetic pole 4, so that an upward force component is thereby created.

To switch the permanent magnet 10 into its other end position, the two coil halves are excited so that, with the polarity of the permanent magnet 10 assumed, the two opposite magnetic poles 1 and 2 are magnetized as south poles and the third magnetic pole 4 as north poles. The south pole of the permanent magnet 10 is repelled by the magnetic pole 2 magnetized as the south pole and the north pole of the permanent magnet 10 is repelled by the third magnetic pole 4 magnetized as the north pole. At the same time, the north pole of the permanent magnet 10 is attracted by the magnetic pole 1 magnetized as the south pole. The permanent magnet 10 is moved toward the magnetic pole 1 by these forces directed towards the magnetic pole 1. The protrusion of the plate 11 over the edge of the third magnetic pole 4 has a favorable effect on the start of the permanent magnet, since this generates a force component directed vertically, as already described for the holding state. When the arrangement is energized, this force component is directed upward and thus supports the start-up of the permanent magnet 10.

As soon as the permanent magnet 10 has reached its other end position, the excitation of the two coil halves 6 and 7 can be switched off again. The permanent magnet 10 holds itself in this end position. By opposing excitation of the two coil halves 6 and 7, the permanent magnet 10 is switched back to the previous end position.

By moving the permanent magnet 10 from one end position to the other, the seal 21 arranged on the spring tongue 9 is lifted from the mouth of the one nozzle opening 20 and pressed against the mouth of the other nozzle opening 19. In this way, a medium flowing through the nozzle openings can be controlled. For example, a liquid can be supplied via the nozzle opening 18, which can then flow out either through the nozzle opening 19 or 20 by appropriately switching the permanent magnet 10.

There is also the possibility of connecting a vacuum accumulator to the nozzle opening 20 and an adjusting device which can be controlled by negative pressure to the nozzle opening 18. In this case, the nozzle opening 19 serves as a ventilation opening. In the position shown, the nozzle opening 20 connected to the vacuum accumulator is initially closed. The two nozzle openings 18 and 19 are connected in terms of pressure via the housing cavity 17. If the permanent magnet 10 is switched by energizing the two coil halves 6 and 7, the seal 21 lies against the mouth of the nozzle opening 19 and releases the mouth of the nozzle opening 20. The negative pressure prevailing in the vacuum accumulator thus becomes effective at the nozzle opening 18. The adjusting device connected to the nozzle opening 18 can be actuated by this negative pressure. If the permanent magnet 10 is switched back again, the seal 21 closes the nozzle opening 20 again and the nozzle opening 18 is again connected to the nozzle opening 19 in terms of pressure, so that the ambient pressure on the adjusting device becomes effective again.

In the drive arrangement shown in Fig. 2, the opposite magnetic poles 22 and 23 are formed as hollow tubes and are concentric in the corresponding coil openings of the two axially spaced coil halves 24 and 25. Between the two coil halves 24 and 25 is a ring 26 as a third magnetic pole inserted ferromagnetic material. This ring 26 lies with its outer circumference on a cylindrical yoke jacket 27. The inference circuit is completed by cover plates 28 and 29 arranged on the end faces of the inference jacket 27 and supporting the hollow tubes 22 and 23. A permanent magnet 32 covered with ferromagnetic plates 30 and 31 is arranged axially displaceably between the two hollow tubes 22 and 23. A plunger 33, which extends through a hollow tube 23 and whose free end 33a is conical, is connected to the permanent magnet 32.

The plunger 33 protrudes into a longitudinal bore 35 provided on a plastic part 34. The plastic part 34 is clamped in the bore of the hollow tube 23 by means of a pipe socket 34a formed on it. At the end of the longitudinal bore 35 there is a control opening 36 provided with a conical counter-seat adapted to the cone of the plunger 33. A further control opening 37 opens into the cavity formed between the plunger 33 and the wall of the longitudinal bore 35.

An amagnetic sealing tube 38 is placed on the outside of the two hollow tubes 22 and 23. The permanent magnet 32 has little play with respect to this sealing tube 38, so that it is not braked by friction during the adjustment. The hollow tube 22 opposite the hollow tube 23 connected to the plastic part 34 is connected at its outer end with a ver conclude. In this closure there is a small bore 39, which can be closed by a further plunger 40 arranged on the opposite side of the permanent magnet 32, or a sealing ring 41 is attached to the end face of the hollow tube, through which the cavity of the hollow tube 22 comes into contact when the permanent magnet 32 is in contact this hollow tube 22 is sealed off from the cavity of the other hollow tube 23 and the longitudinal bore 35.

The drive arrangement works as follows: in the de-energized state of the two coil halves 24 and 25, the permanent magnet 32 holds itself in the respective end position, since its flow through the third magnetic pole 26, the yoke sheath 27, the corresponding cover plate 28 and 29 and that with this connected hollow tube 22 or 23 can close.

The permanent magnet 32 is moved from one end position to the other by appropriate excitation of the two coil halves 24 and 25. In the end position of the permanent magnet 32 shown in FIG. 2, the plunger 33 is raised from the control opening 36 provided at the end of the longitudinal bore 35. There is thus a pressure connection between this control opening 36 and the further control opening 37.

If, for example, the control opening 36 is connected to a negative pressure accumulator or generator, the negative pressure becomes effective at the further control opening 37 and can be used to actuate an adjustment device connected to this control opening. If the permanent magnet 32 is switched to its other end position, the plunger 35 closes the control opening 36 in the manner of a needle valve and the connection to the vacuum source is interrupted. In this position, the further plunger 40 is lifted from the bore 39. There is a connection to the bore 39 via the longitudinal bore 35, the hollow tube 23 and the play between the permanent magnet 32 and the sealing tube 38, so that the ambient pressure at the further control opening 37 and the adjustment device connected to it becomes effective.

The drive arrangement according to the invention only requires a short energy pulse to adjust the permanent magnet 10 or 32. Thereafter, the permanent magnet 10 or 32 holds itself in the respective end position by its magnetism. The use of the drive arrangement is therefore particularly suitable where energy is only available to a limited extent, e.g. in the car. When used in a car, the drive arrangement maintains its respective tax position even when the car is stationary.

Claims (6)

1. Electromagnetic drive arrangement having a permanent magnet (10; 32) arranged in a movable manner between two magnet poles (1, 2; 22, 23) and an actuating element (9; 33), which is connected with the permanent magnet (10; 32), for a mechanical switching operation,

- in which the two magnet poles (1, 2; 22, 23) are arranged with fixed spacing in respect of each other, said spacing limiting the range of movement of the permanent magnet (10; 32), are connected by a return yoke (3; 27) and can be excited electrically in like manner by means of an excitation coil (6, 7; 24, 25) which consistes of two identical half-coils,

- in which there is arranged centrally and laterally outside the clear space between the two magnet poles (1, 2; 22, 23) a third magnet pole (4, 26) which is connected with the return yoke (3; 27) and can be excited in unlike manner in respect of the two first-mentioned magnet poles (1, 2; 22, 23) in that the two half-coils of the excitation coil (6, 7; 24, 25) are arranged on both sides of the connecting point of the third magnet pole (4; 26) with the return yoke (3; 27) and can be excited in opposite senses,

- in which the permanent magnet has on the two sides facing the two first-mentioned magnet poles, in each case, a plate (11, 12; 30, 31 ) of ferromagnetic material.

- in which the permanent magnet (10; 32), including the two plates (11, 12; 30, 31), has a thickness which is greater than the sum of half the spacing of the two first-mentioned magnet poles (1, 2; 22, 23) and half the width of the third magnet pole (4; 26) lying in the direction of adjustment of the permanent magnet (10; 32),

- and an air gap (13) exists between the permanent magnet (10; 32) and the third magnet pole (4; 26), characterised in that the actuating element (9), which is connected with the permanent magnet (10), is provided with at least one control element (21 ) for opening and closing a control opening conducting a fluid,

- in that the thickness of the permanent magnet (10) is greater than the width of the third magnet pole (5) in the direction of adjustment of the permanent magnet (10),

- in that the thickness of each plate (11, 12) arranged on the permanent magnet (10) is at most equal to that width of the third magnet pole (5) in the direction of adjustment of the permanent magnet

- and in that in the two end positions of the permanent magnet (10) the projection of a plate (11, 12) over the corresponding outer edge of the third magnet pole (5) amounts to at most 7.5% of the thickness of this plate.

2. Electromagnetic drive arrangement according to claim 1, characterised in that the two magnet poles (1, 2) and the return yoke (3) which connects them have the form of a C, the third magnet pole (4) being arranged with its free end (5) so that it points to the opening of the C and the permanent magnet (10) being secured to the one end (9a) of a spring tongue (9) which is firmly clamped or pivotably-mounted with its other end (9b) and on which the control element or elements (21 ) are arranged.

3. Electromagnetic drive arrangement according to claim 2, characterised in that the spring tongue (9) is arranged together with the permanent magnet (10) in a housing (8) which has the control openings (19, 20) and is coupled to the magnet poles (1, 2).

4. Electromagnetic drive arrangement according to claim 3, characterised in that the control openings (19, 20) are developed as nozzle openings connected with a low pressure control device and in that the control elements (21 ) are developed as seals (21) arranged on the spring tongue (9).

5. Electromagnetic drive arrangement according to claim 1, characterised in that the two first-mentioned magnet poles are developed as hollow tubes (22, 23) and lie concentrically in openings of the half-coils (24, 25) of the excitation coil, which halves are arranged axially spaced appart from each other, in that the return yoke (27) consists of a cylindrical return casing (27) which surrounds the half-coils (24, 25) and two cover plates (28, 29) which support the hollow pins (22, 23) and are joined to both faces of the return casing, in that inserted between the two hollow pins (22, 23) as a third magnet pole there is a ring (26) which rests with its outer edge against the return casing (27) and in that the actuating element consists of a plunger (33) which is arranged on at least one side of the permanent magnet (32) and which passes through one hollow tube (23) and the free end (33a) of which is developed conically.

6. Arrangement according to claim 5, characterised in that the free end of the plunger (33) is surrounded by a plastic portion (34) which is provided with a longitudinal bore hole (35) and which by means of a tube connection piece (34a) which surrounds the hollow tubes (23), and in that the plastic portion (34) has a first control opening (36) and a second control opening (37), the first control opening (36) being provided with a corresponding conical counter-seat to receive the free end of the plunger (33).

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