WO2008071375A2 - Electrical control device - Google Patents

Abstract

The invention relates to an electrical control device with a magnetic field-sensitive sensor and a magnet spaced apart from the sensor which, starting from a central position, is movable both in a first direction of motion and in a second direction of motion relative to the sensor, wherein the sensor can be used to provide a control signal according to the relative position of the magnet. In order to develop the control device in such a way that a control signal can be generated in a constructionally simple manner according to the direction of motion of the magnet, starting from the central position thereof, it is proposed according to the invention that the direction of the magnetic field prevailing at the location of the sensor be reversible by moving the magnet in different directions of motion starting from the central position.

Description

 Electric control device

The invention relates to an electrical control device with a magnetic field-sensitive sensor and a magnet spaced from the sensor, which is movable relative to the sensor, starting from a center position in both a first direction of movement and in a second direction of movement, wherein by means of the sensor dependent on the relative position of the magnet Control signal is available.

Such control devices are used, for example, in the form of radio remote controls, with the aid of which an electrically controllable device, for example an agricultural or forestry machine, can be controlled. For this purpose, the magnet can be moved relative to the sensor and, depending on the position of the magnet relative to the sensor, this provides a control signal that can be transmitted to the machine to be controlled. Such an electrical control device is described in the patent DE 103 04 595 B3.

To generate a control signal, the magnet can be moved relative to the sensor, starting from a middle position, both in a first direction of movement and in a second direction of movement. This gives the possibility of generating a control signal dependent on the respective direction of movement. For this purpose, usually several sensors are used, for example, three sensors, so that upon movement of the magnet, starting from its center position in the first direction of movement, the magnet is approached to a first sensor and at the same time a removal of a second sensor. The sensor signal of the first sensor is thereby amplified and the sensor signal of the second sensor is weakened. The different sensor signals can then be evaluated by means of an evaluation unit such that the direction of movement of the magnet can be detected. This makes it possible, depending on the direction of movement of the magnet, for example, to control an electric motor optionally for rotation in a first rotational direction or in a second rotational direction opposite thereto. However, the use of multiple sensors is associated with not inconsiderable manufacturing and assembly costs.

Object of the present invention is therefore to develop an electrical control device of the type mentioned in such a way that in a structurally simpler manner, a control signal can be generated, which is dependent on the direction of movement of the magnet, starting from its center position.

This object is achieved according to the invention in an electrical control device of the generic type in that the direction of the magnetic field prevailing at the location of the sensor is reversible by moving the magnet starting from the middle position in different directions of movement.

In the control device according to the invention a magnetic field is generated at the location of the sensor in a movement of the magnet starting from the center position in the first direction of movement, which is opposite to the magnetic field, which in a movement of the magnet from its center position in the second direction of movement at the location of the sensor is present. The field lines of a magnet run from its north pole to its south pole. According to the invention, at the location of the sensor, the magnetic field in a movement of the magnet, starting from its middle position in the ste movement direction in a direction opposite to the magnetic field, which forms at the location of the sensor when the magnet is moved from its center position in the second direction of movement. For example, it can be provided that the magnetic field is aligned substantially parallel to the surface of the sensor when the magnet assumes its central position. If the magnet is moved in the first direction of movement, the magnetic field can be oriented obliquely or perpendicular to the surface of the sensor, the field lines facing the sensor surface. If, in contrast, the magnet is moved starting from its middle position in the second direction of movement, then the magnetic field can also be oriented obliquely or perpendicular to the surface of the sensor, although the field lines of the sensor surface are turned away.

The control signal generated by the sensor is dependent both on the magnitude and on the direction of the magnetic field prevailing at the location of the sensor. Thus, it can be provided, for example, that during a movement of the magnet, starting from its center position in the first direction of movement, a positive control voltage is generated, whereas a negative voltage signal is provided by the sensor when the magnet moves from its center position into the second direction of movement. Thus, it is only a single sensor required to generate by means of the electrical control device according to the invention from the direction of movement of the magnet, starting from the central position-dependent control signal.

The electrical control device according to the invention can for example form a forward-reverse switch for driving an electric motor, which generates a forward movement in a movement of the magnet, starting from its central position in the first direction of movement and generates a movement of the magnet, starting from the central position in the second direction of movement of the forward movement opposite backward movement. In this way, for example, in construction crane, a load can be selectively raised or lowered by moving the magnet in the first or second direction of movement. The respective distance of the magnet to the center position can serve as a measure of the speed of the driven electric motor.

It is favorable if, in the middle position of the magnet, the magnetic field prevailing at the location of the sensor is minimal. A deflection of the magnet from the center position then leads, regardless of the direction of movement, to an increase in the magnetic field prevailing at the location of the sensor.

The center position of the magnet can correspond to a zero position in which the electric motor controlled by the control device is stopped.

It is advantageous if the sensor is associated with a deflecting element for bundling the magnetic field lines emanating from the magnet. Such a deflecting element may be in the form of a yoke which is made of a soft magnetic material, preferably of an iron material. With the aid of the deflecting element, the magnetic field lines can be guided and bundled, in particular in the region of the sensor.

It is advantageous if, by means of the deflecting element in the middle position of the magnet, the magnetic field lines pass to a greater extent on the sensor. bar are as in a different position of the magnet from the middle position. In such an embodiment, the magnetic field lines in the central position of the magnet can be passed to a large extent on the sensor. With increasing deflection of the magnet from the center position then increases the density of the magnetic field lines at the location of the sensor.

Preferably, the sensor is arranged in the middle position of the magnet between the magnet and the deflecting element. The deflecting element is thus located on the side of the sensor facing away from the magnet and guides at least part of the magnetic field lines around the sensor, so that the magnetic field is weakened at the location of the sensor when the magnet assumes its central position.

In a preferred embodiment, the deflection element has two legs, which are connected to one another on the side facing away from the magnet of the sensor via a web. It is particularly advantageous in this case if the legs are aligned perpendicular to the web. The deflecting element is thus preferably U-shaped and the sensor is positioned between the two legs.

It is advantageous if the sensor is arranged centrally between the two legs, because thereby a symmetrical with respect to the center position of the magnet control signal can be generated.

It is particularly favorable when the deflecting element has a post protruding from the web between the two legs, on which the sensor is mounted is arranged. As a result, the sensitivity of the sensor with respect to the direction of movement of the magnet can be increased.

It is advantageous if the deflecting element is designed as a one-piece or multi-part sheet metal part. This allows a particularly cost-effective production of the deflecting element.

The magnet may be configured for example in the form of an electromagnet. It has proved to be advantageous, however, if it is designed as a permanent magnet, preferably as a bar magnet, because this can eliminate a power supply for the magnet.

The sensor is formed in an advantageous embodiment as a Hall sensor.

The movable magnet can be mounted, for example, displaceable or pivotable. A pivotal mounting has proven to be particularly favorable. Depending on the pivoting angle of the magnet, a control signal can be generated with the aid of the sensor, the amount of which depends on the pivoting angle and its sign on the pivoting direction of the magnet.

It is favorable if the control signal generated by the sensor is proportional to the deflection of the magnet from the middle position.

The magnet is held in an advantageous embodiment of the invention on a pivotally mounted actuating lever. The lever may be formed with two arms, wherein a first lever arm as a handle for the loading serves user and the second lever arm, preferably in the region of the free end, the magnet is arranged.

In order to simplify the repair of the control device according to the invention, it is advantageous if the control device has an actuating part and a closed housing, wherein the actuating part is detachably connectable to the housing and the magnet comprises, and wherein the housing receives a printed circuit board on which Sensor is arranged. This makes it possible to arrange the sensor which is sensitive to external influences within the closed and preferably dustproof and / or watertight housing. In addition to the sensor, the housing can accommodate an electrical evaluation unit, which is also protected by the positioning within the housing from external influences. The actuating part receives the movable magnet. The magnet may for example be pivotally mounted in the actuating part. In contrast to the sensor, the magnet is very insensitive to moisture and dirt. If, due to intensive use of the control device, the bearing of the magnet is damaged, then the entire actuating part, including the magnet, can be exchanged in a simple manner. For this purpose, the actuating part on the housing is releasably held. The actuating part may for example be screwed or locked to the housing. Thus, the control device according to the invention can be repaired in a simple manner.

Preferably, the actuating part comprises a releasably connectable to the housing base part in which a pivotable or displaceable actuating member is mounted, wherein the actuating member of the magnet is arranged. The actuator may be formed for example in the form of a sliding part, which is mounted displaceably in a guide formed by the base part and receives the magnet.

It is particularly advantageous if the actuating member is designed as a two-armed pivot lever, wherein a first Schwenkhebelarm protrudes from the base part and wherein the magnet is arranged on the second Schwenkhebelarm. The first Schwenkhebelarm can form a handle by means of which the user can pivot the magnet relative to the sensor both in a first direction of movement and in a direction opposite to the first direction of movement second direction of movement.

The following description of preferred embodiments of the invention is used in conjunction with the drawings for further explanation. Show it:

Figure 1: A sectional view of a first embodiment of an electrical control device according to the invention;

FIG. 2 shows a schematic representation of the control signal which can be generated by means of the control device according to FIG. 1;

FIG. 3 shows a partial sectional view of a second embodiment of an electrical control device according to the invention with a magnet in a middle position; 4 shows a partial sectional view according to FIG. 3, wherein the magnet is pivoted starting from its middle position in a first direction of movement and

Figure 5: a partial sectional view according to Figure 3, wherein the magnet is deflected starting from its central position in a second direction of movement.

1 shows schematically a first embodiment of an electrical control device is shown, which is generally occupied by the reference numeral 10. It comprises an actuating part 12 and a closed, preferably dust and / or watertight housing 14. Within the housing, an electrical circuit board 16 is arranged, on the upper side of which a magnetic-field-sensitive sensor, in the illustrated embodiment a Hall sensor 18, is arranged. On the side facing away from the Hall sensor 18 bottom 20 carries the circuit board 16 made of a soft magnetic material, preferably an iron material magnetic deflection element 22 with a voltage applied to the bottom 20 web 23, the two perpendicular to the web 23 aligned and immersed in the circuit board 16, the Circuit board 16 preferably cross-leg, 24, 25 integrally connected to each other. Centered between the two legs 24, 25 of the web 23 carries a likewise perpendicular to the web 23 aligned post 26, which also dips into the circuit board 16 and this preferably passes through, it is advantageous if the Hall sensor 18 is seated on the post 26.

Below the circuit board 16, an electrical evaluation unit 28 is disposed in the housing 14, which is known per se and therefore in the drawing not shown electrical connecting lines is connected to the Hall sensor 18.

Above the Hall sensor 18, the housing 14 forms a recess 30. In the recess 30, a base part 32 of the operating part 12 with a base plate 34 is immersed, which is detachably connected to the housing 14 in the drawing to achieve a better overview, not shown releasable connecting elements, such as connecting screws or latching hooks. The base plate 34 is integrally connected on its side facing away from the housing 14 with a hood 36 which has an elongated opening 37 on its upper side facing away from the housing 14. Within the hood 36 an actuating member in the form of a two-armed pivot lever 40 is pivotally mounted about a pivot axis 39, the first Schwenkhebelarm 41, the opening 37 passes through and upward, d. H. in the housing 40 facing away from the hood 36 protrudes. The second Schwenkhebelarm 42 is disposed within the hood 36 and carries, adjacent to its free end, a magnet, which is formed in the illustrated embodiment as a cuboid bar magnet 44.

Both the actuating part 12 and the housing 14 are made of a plastic material and thus permeable to the magnetic field generated by the bar magnet 44. The magnetic field is detected by the Hall sensor 18. Depending on the position of the magnet 44 relative to the Hall sensor 18, the Hall sensor 18 provides an electrical control signal, which is shown simplified in Figure 2 in a coordinate system. The deflection of the pivoting lever 40 is shown on the abscissa and the ordinate shows the output voltage of the Hall sensor 18 as a function of the deflection of the pivoting lever 40. It is clear that the control signal of the Hall sensor 18 is proportional to the deflection of the pivot lever 40 and thus also proportional to the deflection of the bar magnet 44. Is the magnet 44 in the middle position shown in Figure 1, the deflection is 0% and from the Hall sensor 18, a control voltage in the amount of 2.5 volts is provided. If the pivot lever 44 is pivoted in the clockwise direction so far that the first Schwenkhebelarm 41 rests on the right edge of the opening 37, the deflection is +100% of the maximum deflection and the Hall sensor 18, a control voltage of about 4.7 volts is generated. If the pivot lever 40 is pivoted counterclockwise so far that the first Schwenkhebelarm 41 rests on the left edge of the opening 37, the deflection is -100% of the maximum deflection and the Hall sensor 18 is a control voltage in the amount of about 0.3 volts provided. The control signal is thus dependent both on the direction of movement and on the distance of the bar magnet 44 relative to the Hall sensor 18.

The electrical control device 10 may be designed in particular in the form of a radio remote control device, with the aid of which an electrical device, in particular an electric motor, can be controlled. By pivoting the pivot lever 40, both the speed and the direction of rotation of the electric motor can be specified.

FIGS. 3 to 5 show a second embodiment of an electrical control device, which is designated overall by the reference numeral 50. This is largely identical to the previously described with reference to Figure 1 control device 10. In Figures 3, 4 and 5, the same reference numerals are therefore used for identical components as in FIG. 1. With regard to these components, reference is made to the above explanations in order to avoid repetition.

The electric control device 50 differs from the control device 10 substantially in that a bar magnet 54 is used, which is curved in a circular arc.

In Figure 3, the electrical control device 50 is shown, wherein the pivot lever 40 and thus also its bar magnet 54 occupies a central position. In this middle position, the deflecting element 22 of the control device 50 is arranged on the side facing away from the bar magnet 54 side of the Hall sensor 18. The magnetic field generated by the bar magnet 54 is illustrated schematically in FIGS. 3, 4 and 5 by the field lines 56. The field lines 56 extend from the north pole N of the bar magnet 54 to the south pole S. In the middle position of the bar magnet 54, the field lines 56 emanating from the north pole N meet at a short distance from the north pole N to the first leg 24 of the deflecting element 22. Starting from the first leg 24 The field lines run mostly within the deflection element 22 to the free end of the second leg 25, from which they extend to the south pole S. The deflection element 22 thus bundles the field lines 56 and, in the middle position of the bar magnet 54, largely guides them past the Hall sensor 18.

However, if the pivot lever 40 and with this also the bar magnet 54, starting from its zero position in a first direction of movement 51, pivoted in the illustrated embodiment in the clockwise direction, as shown in Figure 4, so much of the field lines, starting from the North pole N on the first leg 24 into the magnetic deflection element 22, already on the post 26 out of the deflecting element 22, where they pass through the Hall sensor 18 from bottom to top, and then hit the south pole S of the bar magnet. Thus, the magnetic field strength prevailing at the location of the Hall sensor 18 increases with increasing deflection of the bar magnet 54 from its center position.

If the pivot lever 40 and thus also the bar magnet 54 is pivoted, starting from the central position thereof in the second direction of movement 52 opposite the first direction of movement 51, ie in the illustrated embodiment counterclockwise, as shown in FIG. 5, then the north pole N of FIG Bar magnets 54 outgoing field lines to a considerable extent on the post 26 in the magnetic deflecting element 22 so that they pass through the Hall sensor 18 from top to bottom, and the second line 25, the field lines from the deflection element 22 come out again and then hit The south pole S. The direction of the prevailing at the location of the Hall sensor 18 magnetic field is thus dependent on the position of the bar magnet 54. This has the consequence that the output voltage provided by the Hall sensor 18 increases linearly in a deflection of the bar magnet 54 from the central position in the first direction of movement 51, whereas it linearly decreases in a deflection of the bar magnet 54 from the middle position in the second direction of movement 52, as already explained with reference to FIG.

From the foregoing, it is clear that the direction of the magnetic field prevailing at the location of the Hall sensor 18, both in the electrical control device 10 and in the electrical control device 15 by moving the magnet 44 or 54 from the middle position into different directions. tion directions 51 and 52 is reversible. Thus, a control signal can be generated in a structurally simple manner when using only a single Hall sensor 18, which is dependent on the direction of movement of the magnet 44 or 54. Such control devices 10, 50 are particularly suitable as radio remote controls for wired or wireless control of electrical appliances, in particular electric motors.

Claims

1. Electrical control device with a magnetic field-sensitive sensor and a magnet spaced from the sensor, which is movable relative to the sensor, starting from a central position in both a first direction of movement and in a second direction of movement, wherein by means of the sensor dependent on the relative position of the magnet control signal available is characterized in that the direction of the prevailing at the location of the sensor (18) magnetic field by moving the magnet (44; 54), starting from the center position in different directions of movement is reversible. 2. Control device according to claim 1, characterized in that in the middle position of the magnet (44; 54) at the location of the sensor (18) prevailing magnetic field is minimal. 3. Control device according to claim 1 or 2, characterized in that the sensor (18) is associated with a deflecting element (22) for bundling the magnet (44; 54) outgoing magnetic field lines (56). 4. Control device according to claim 3, characterized in that by means of the deflecting element (22) in the central position of the magnet (44; 54) the magnetic field lines (56) can be guided to a greater extent on the sensor (18) than in a different position from the middle position Position of the magnet (44, 54). 5. Control device according to claim 3 or 4, characterized in that the sensor (18) in the middle position of the magnet (44; 54) between the magnet (44; 54) and the deflecting element (22) is arranged. 6. Control device according to claim 3, 4 or 5, characterized in that the deflecting element (22) has two limbs (24, 25) which, on the side of the sensor (18) remote from the magnet (44; 23) are interconnected. 7. Control device according to claim 6, characterized in that the sensor (18) is arranged centrally between the two legs (24, 25). 8. Control device according to claim 6 or 7, characterized in that the deflecting element (22) between the two legs (24, 25) from the web (23) projecting post (26), on which the sensor (18) is arranged. 9. Control device according to one of claims 3 to 8, characterized in that the deflecting element (22) is designed as a sheet metal part. 10. Control device according to one of the preceding claims, characterized in that the magnet as a permanent magnet (44; 54) is configured. 11. Control device according to one of the preceding claims, characterized in that the sensor is designed as a Hall sensor (18). 12. Control device according to one of the preceding claims, characterized in that the magnet (44; 54) is pivotally mounted. 13. Control device according to claim 12, characterized in that the magnet (44, 54) is held on a pivotally mounted actuating lever (40). 14. Control device according to one of the preceding claims, characterized in that the control device (10, 50) has an actuating part (12) and a closed housing (14), wherein the actuating part (12) with the housing (14) is releasably connectable and the magnet (44, 54) and wherein the housing (14) receives a circuit board (16) on which the sensor (18) is arranged. 15. Control device according to claim 14, characterized in that the actuating part (12) comprises a housing (14) releasably connectable base part (32) in which a pivotable or displaceable actuating member (40) is mounted, wherein the actuating member (40 ) the magnet (44; 54) is arranged. 16. Control device according to claim 15, characterized in that the actuating member is designed as a two-armed pivot lever (40), wherein a first Schwenkhebelarm (41) protrudes from the base part (32) and wherein on the second Schwenkhebelarm (42) of the magnet (44; ) is arranged.