DE1082972B - Small direct current rotating field motor, especially for radio systems - Google Patents

Description

Small direct current rotating field motor, especially for radio systems The invention relates to a small direct current rotating field motor, in particular for radio systems, preferably for vehicle radio systems.

The known micro-DC motors used in vehicle radio systems for remote switching of crystals or channels have the disadvantage that they are after standing in a switching position between coal and sliding collector for a longer period of time Form an oxide layer, which means that the engine will not start the next time the gear changes, so that the crystal or channel cannot be set to the desired frequency can.

Also often caused by the graphite dust from the carbon brushes at low Humidity after prolonged standing in one place such a crust the collector's grinding surface means that the motor cannot work.

Simply replace the collector with non-oxidizing metal, fails because there are no precious metals to date when they are used two precious metals could be grinded against each other without them being mutually exclusive eroded apart from being economical with the necessary size of the parts would not be acceptable.

However, this state now sets the operational uncertainty of the radio system very much down.

In addition, it is difficult to create multi-part grinding collectors for miniature motors to be set up in a reliable manner. It is therefore known to call the runner cylindrical To design permanent magnets and to provide spring contacts instead of a collector, which are controlled by one or more cams on the rotor shaft. These contacts lead to the stator winding (s) the operating voltage in such a way that an alternating or rotating field is created. The disadvantage of such known contact motors consists in the fact that the rotating field generated is coarse or even has places, in which the motor cannot start by itself.

However, it is also desirable to have very small motors with a finely graduated, continuous To operate rotating field, as it is with large motors with multi-pole armature and fine divided collector is the case.

For the transmission of control values it is z. B. known, an electromagnet system to be provided with a stator or rotor winding connected in a triangle, which is connected to a switch via three wires. With the help of this switch the operating voltage is applied to the windings in twelve positions in such a way that the electromagnetic system a rotary movement of 30 degrees per switch position of the encoder executes.

It is also known to use a magnetic motor with a delta connection To provide stator winding, the two-part via a located on the rotor shaft Collector is connected to the operating voltage in such a way that the desired twelve-digit rotating field is created. This well-known motor is intended for toys and therefore does not need to meet the requirements for a commercial radio be asked. A major disadvantage of this engine is that the The operating voltage is applied to the collector via an additional pair of brushes, so that two brushes are always connected in series. Through this The operational safety is further reduced.

The direct current rotating field small motor according to the invention has this Disadvantages does not have and has the characteristic that to form the rotating field and thus three or more changeover contacts to generate a uniform rotary movement, which are controlled by cam disks of the rotor shaft are provided, whose Center contacts to the stator windings and their power supply contacts to the Supply voltage are connected.

The invention is based on the drawing, which shows an embodiment represents, explained in more detail. In FIGS. 1 to 5, an exemplary embodiment is shown in addition Individual parts shown in schematic form.

As can be seen from FIGS. 1 to 5, the rotor consists of one diametrically magnetized, cylindrical permanent magnet 1, which is on the drive shaft 2 is attached, which in turn by means of the two ball bearings 3 and 4 in the motor housing 5 is rotatably mounted. In the motor housing 5 are with a appropriate Air gap around the armature 1, the three pole shoes 6 offset by 120 ° each arranged, which form the stator with the three coils 7. The coils are in delta connection connected with each other.

On the end of the rotor axis 2 opposite the drive side three insulating cam disks 8 are attached, each of which has two precious contact springs 9 raise them in a certain order, in turn in two groups of three each are lined up conductively on a standing beam 10, which at the same time the DC connection terminals, of the engine.

The stationary mating contacts 11 are insulated on the stud bolt 12 lined up and electrically connected to the coils 7.

The three insulating cams 8 are shaped at their edge and to one another arranged offset by 120 ° in the direction of rotation on the rotor axis 2 that in a rotating field is created in the three pole pieces 6 or in the stator when the motor is running, which consists of twelve steps per rotor revolution, what a collector motor with a twelve-part anchor.

Furthermore, the cams and the contact arrangement for the stator axis 2 and stored in relation to the rotor's magnetic field so that the rotating field always touches the armature leads by 60 ° in the direction of rotation.

The different polarizations caused by the cams are indicated schematically in FIG. 5 with the numbers 1 to 12. The cam disks 8 ', 8 ", 8"' are only drawn symbolically. The crescent-shaped symbols mean however, not that the angles which the cams enclose with one another represent the positions correspond.

As a result of the prediction of the rotating field, the case never occurs that the anchor comes to a "dead point" after a standstill or Contact problems occur, so that the engine always starts.

The motor according to the invention is mainly used as a miniature motor for remote-controlled Quartz switches, remote changeover switches and remote tuning devices, e.g. B. with potentiometers od. Like. And for pause signal generator, suitable.

Claims (4)

PATENT CLAIMS: 1. DC motor, in particular for radio systems, preferably for vehicle radio systems, with permanent magnet rotor, cam-controlled Contacts and with stator windings connected in a triangle, in which one around at least twelve identical steps progressing rotating field is generated, characterized in that that for the formation of the rotating field three or more changeover contacts, those of cam disks the rotor shaft are controlled, the center contacts of which are connected to the stator windings and whose power supply contacts are connected to the supply voltage. 2nd engine according to claim 1, characterized in that the central contacts of the cam switch isolated on a stud bolt (10) are lined up and that the as U-shaped springs trained power supply contacts on contact closure with the center contacts are adjusted and of the cam disks in the area necessary to create the rotating field Sequence to be withdrawn. 3. Motor according to claim 1 and 2, characterized in that that the contact springs (9) and the cam disks (8) to the motor axis and to the polarity of the permanent magnet rotor are set so that the rotating field of the motor dem Permanent magnet rotor leads by 60 °. 4. Motor according to claim 1 to 3, characterized in that that the contact springs (9) are attached to two stud bolts (1 (k), which at the same time for holding the sealing cap and as connecting terminals for the power supply to serve. Publications considered: German Patent Specifications No. 836968, 867 567, 714194; British Patent Nos. 467 846, 526 896; French patents No. 860 668, 890 826; Arnold, "The armature windings and armature constructions of direct current dynamo machines", 3rd edition, 1899, p. 221, paragraphs 1 and 2.