FR2632791A1 - DIRECT CURRENT MOTOR AT ONE OR MORE SPEEDS FOR DRIVING WINDSCREEN WIPER BLADES - Google Patents

Abstract

This motor comprises two armatures whose collectors 18-19 each comprise two brushes 20-21 and 22-23 associated with a switching means 33, a motor characterized in that, on one of the collectors 19, a third brush 24 is provided. and that the connection means 33 connects in series with a direct current source 34: for the highest rotational speed III the third brush 24 and the brush 23 of this collector 19 being peripherally furthest away; for an average speed of rotation II, the two diametrically opposed brushes 22, 23 of one of the two collectors 19; for the lowest speed of rotation I the opposite brushes 20-21, 22-23 of the two collectors 18, 19.

Description

i DC motor with one or more speeds

  for driving vehicle wiper blades

automotive vehicles ".

  The invention relates to a DC motor, in particular a small motor, intended for

  automotive windscreen wiper drive

  according to several speed regimes comprising a magnetic pole, in particular a permanent magnet pole, a carrying stator, with a rotor which comprises two collectors each provided with two diametrically opposed brushes, and two armature windings insulated galvanically, which are each connected to one of the collectors and with

  connection means connected to the brushes for the branch-

  of these on a continuous voltage source

  bare by a choice of separate connection or branch-

series of collectors.

  Such DC motors with two collectors are known to produce two or more speeds of rotation, for example according to

  patent applications DE-OS-29 04 904, or DE-OS-

  21 01 459, or DE-OS-48 55 987. The different rotational speed regimes are also obtained optionally, by series connection, parallel connection or separate connection of only one of the two windings advantageously formed identically, which is achieved by the brushes. The DC motors have a speed and torque behavior, according to the characteristic curves of FIG. 1 which, in this case, are represented so that in the lowest speed I speed regime, the two armature windings be

  connected in series, in the rotational speed regime

  medium tion II, only one armature winding is connected, and in the highest rotational speed regime III, the two windings are connected

  in parallel. In view of these characteristic curves,

  DC motors are not specific

  especially suitable for use on paper towels

  motor vehicle windows, and indeed on the following bases: The difference in speed between the two highest speed regimes on wet windows is very small. The locking torque (n = 0) in the

  highest rotational speed is double

  wheat as high as in other rotational speed regimes. The blocking current is in the highest speed regime, several times as high as in other speeds. If the two armature windings are caused to move in a manner which is not identical, but on the contrary different, the disadvantages mentioned above can be mitigated in this way, but the losses by the transverse currents and the other factors are so high, that double manifold motors do not

  are more interesting because of their poor

-deally.

  According to patent GB-PS-1 052 338, it is known

  a direct current motor was born for the

  trailing wipers, which usually

  is equipped with a single collector and a single reel

  armature. To get a second speed-quick

  rotation, a third broom is provided on the

  collector, which is placed offset at the peri

  collector distance less than 180 'compared to

  one of the two roughly diameter collector brushes

  trally opposite on the periphery. In the regime of * lower speed of rotation, the two brushes of diametrically opposite collectors on the collector are connected to the source of direct current, while in the regime of higher speed of rotation,

  the third collector brush and the one that is.

  ve furthest away from it are powered by the

direct current source.

  The DC motor according to the invention

  tion is characterized in that, on one of the collec-

  A third brush is provided which is placed, relative to one of the two brushes of this collector, so as to be offset by an angle less than 180 on the periphery of the collector, and in that, for a speed of high rotation, the connection means connects in series, the third collector brush and the brush of this most distant collector with the direct current source, in that for an average speed of rotation the switching means connects in series, the two diametrically opposed brushes of one

  of the two collectors and the direct current source-

  and in that for a low speed of rotation the connection means connects in series, the armatures by connecting to each other the four brushes of

  diametrically opposite manifold.

  This motor has the advantage that it is suitable as a DC motor with double manifold without significant constructional modifications for windshield wipers of a motor vehicle, and furthermore also has a drive with three rotational speeds in well staggered intervals in the case of wet windows. The speeds of rotation between the three speeds of the latter make it possible to fix them at the chosen operating point of the DC motor. As we can see on the curves

  characteristics of the rotational speed behavior

  tion and behavior of the torque of the DC motor according to the invention shown in FIG. 2, the locking torques (n = 0) differ only slightly in the three speed revolutions at the periphery. The slowest engine blocking torque can to a large extent be fixed in one

  desired relationship to the other two regimes.

  In practice, these three blocking couples are however grouped together closely, since the

  wiper motor must perform the function of

  soaking in each regimen also under conditions

difficult situations.

  On the DC motor for wipers

  glass according to the invention, motors with double manifold such as those found as a motor for cooling fans on motor vehicles have already received numerous applications,

  are used practically-without modification. Simple-

  ment, a brush holder on a collector is replaced in place of a brush holder by three collector brushes. In general, the DC motor remains unchanged, as it is used as the fan motor. Thus, there is a field of use for the double manifold motor.

  even wider, so that we can get as well

  if a reduction in the cost price by the possibility

  to mass produce a large number of objects.

  Other variants and improvements before-

  geuses of the DC motor are characterized in that the collector comprising the collector brushes which are connected in series to the DC current source for the speed regime of medium rotation, is provided with the third collector brush.

  According to another characteristic of the

  vention, to obtain a fourth speed of rota-

  between the high and medium speeds, the connection means connects in series the third

  collector's broom, the most distant broom

  hindered on the periphery of this collector as well as the

two brushes from the other collector.

  According to another characteristic of the

  vention, the other collector also comprises a third brush which is connected to the connection means and can be coupled in parallel or in series by the latter to obtain other speeds of rotation. speed with the other collector brushes and the induced. The invention is explained in more detail with the aid of an exemplary embodiment shown in the

  figures in the following description. We show:

  - in Figure 1, each of the characteristic curves of a double manifold motor known per se and - in Figure 2 the DC motor for each of the three rotational speed regimes, - in Figure 3, - a connection diagram of the DC motor, - in Figure 4, a summary table of positions

  of connection in the connection diagram of the fig-

  re 3 in the three rotational speed regimes, - in Figure 5, a schematic representation of the side view of an embodiment of the construction of the

DC motor.

  The bipolar DC motor shows

  shown diagrammatically in FIG. 5 intended for the

  dragging of a motor vehicle windshield wiper according to several speed regimes, comprises a stator 11 fixed in a housing 10 and a rotor 13 being rotationally fixed on a rotation shaft 12 supported in the housing while sparing

  an air gap 14 in the stator 11. As has been shown

  symbolically felt in Figure 3, the stator 11 carries

  two permanent magnet poles 15 which in the usual way

  are made in the form of two half segments

  shells. The rotor 13 carries two windings of

  duit 16, 17 galvanically isolated from each other which

  are represented in FIG. 5 by two rods conduc-

  armature windings 16, 17 are regularly distributed around the periphery of the rotor and are usually found in radial grooves. They

  can be made identically, i.e.

  say have the same windings. In the way

  simpler, the two windings can be reali-

  sés from a two-wire coil.

  The rotor 13 carries correspondingly to its two armature windings 16, 17 two collectors 18, 19 on each of which is connected one of the two armature windings 16, 17. On the manifold 18, on the right in FIG. 5 are placed two roughly diametrically opposite collector brushes 20-21,

  which - as is not shown in more detail here -

  are received in a brush holder fixed on the bowl

  tier 10. On the collector on the left in Figure 5, are generally wedged three collector brushes 22, 23, 24 whose collector brushes 22 and 23 are located diametrically opposite on this collector, while the third collector brush 24 is offset from the collector brush 22 by less than 180 on the periphery of the collector. The brush terminals 25 - 29 are placed on a terminal plate 30 which is arranged on the cover of the transmission 31 of a gearbox 32. From the brush terminals 25 - 29, the connection lines lead to means of. connection 33 which are represented in the figure by two separate connectors, 36. By means of this connector 33, the DC motor is connected to a DC voltage source, as is shown in FIG. 3 by a storage battery 34. For each position of the connectors 35, 36, the DC motor takes

  three speed regimes 1, II and III with different

  net rotational speed between speed regimes. The connector 35 has three connection positions 0, 1 and 2 while the connector 36 can be connected between positions 1 and 2. * On the table in Figure 4, the speed regimes or the connector connection positions are given 35, 36 that the connectors must take to achieve the desired rotational speed regimes I, II and III, the regime I representing the lowest speed and the regressed III the highest speed. As can be seen in FIG. 3 associated with FIG. 4, in the highest speed regime III, the third collector brush 24 and the collector brush 23 are connected to the storage battery of the vehicle 34. In the average speed speed II the connector goes from its connection position 1 to its connection position 2 to connect the switch brushes 22 and -23 to the battery. In the speed regime the

  below, the collectors' brushes 20 -'23 are connected.

  serial and are connected to the storage battery

  of the vehicle. This is done by the 'passage of

  connector 36 from its connection position 1 to its posi-

  tion of connection 2, the connector 35 remaining in its connection position 2. In the lowest speed regime I, the two armature windings 16, 17 of the

  DC motors are connected in series.

  In the diagram in FIG. 2, the characteristic curves n = f (M) and I = f (M), of the motor at

  direct current are represented for the three regi-

  speed measurements I, II and III. The operation of the DC motor on wet windows is

  represented by a defined speed range

  nor by dotted lines. It is obvious that the speeds of rotation are well staggered in the speeds of rotation or in the speed regimes of the wipers I - III. Locking torques (n =

  0) differ little for the three regimes.

  On the terminal plate 30, there are also three other terminals 37, 38 and 39 for the mechanical disengagement of the DC motor at the end of the stroke.

  after passage of the connector 35 to its disconnected position

  nexion 0. The description of this connection circuit

  known per se will not be made here.

  To obtain the average speed of rotation speed II, for armature windings produced in an identical manner, it is also possible to connect the collector brushes 20, 21 of the collector 18 in place of the collector brushes 22, 23 of the collector 19

  on the vehicle's storage battery.

  If you want another speed regime, you can still provide a combination of the position

  connection so that the connector 35 takes

  ne its connection position 1 and the connector 36 its connection position 2. In this way, the collector brushes 24, 23, 21 and 20 are connected in series (FIG. 4). The speed of rotation of this regime, "IV transmission" is between the third and the

  second speed regime III and II respectively.

2,632,791

  Correspondingly, the characteristic curves develop in FIG. 2 between the curves

characteristics II and III.

  In a modification not shown of the motor with double collector, the collector 18 can also be provided with a third collector brush which is placed on a sixth brush terminal brought from the outside. By the corresponding design of the connection means 33 for now the six collector brushes, one can couple the latter with each other, so that by connection in parallel or in series of the windings 16, 17 connected to the collector brushes , we can get a lot of

  characteristic curves according to figure 2 for different

rents speed regimes.

Claims (4)

  1 ') Direct current motor, in particular a small motor, intended for driving, for   stepped gears, windscreen wipers for motor vehicles   biles, comprising a magnetic blade, in particular a permanent magnet pole, a stator (11), a rotor (13) which comprises two collectors (18, 19) each provided with two diametrically opposed brushes, and two armatures (16, 17) galvanically isolated from each other which are each connected to one of the collectors (18, 19), connection means connected to the brushes for the separate or series connection of these armatures on a DC voltage source, motor characterized in that   that one of the collectors (19) is provided for three   fifth brush (24) which is placed, relative to one of the two brushes of this collector (23), so as to be offset by an angle less than 180 'on the periphery   of the manifold, and in that, for a rotational speed   tion (III), the connection means (33) connects in series, the third collector brush (24) and the brush of this collector (23) furthest from the direct current source (34), in that for a   average rotation speed (II) the switching means   tion (33) connects in series, the two diametrically opposite brushes (22, 23) of one of the two collectors (19) and the direct current source (34) and in that for a low rotation speed (I) the connection means (33) connects in series, the armatures (16, 17) by connecting to each other the four brushes   diametrically opposite manifold (20-23-).   2 ') Motor according to claim 1, charac-   characterized in that the collector (19) comprising the collector brushes (22, 23) which are connected in series to the direct current source (34) for the speed of   average rotation speed (II), is equipped with the third- collector broom (24).   3 ') Motor according to claim i or claim 2, characterized in that to obtain a fourth speed of rotation lying between the high and medium speeds (III, II) the connection means (33) connects in series the third brush (24) of the collector (19), the brush (23) which is furthest from it on the periphery of this collector as well as the two brushes (20, 21) of the other collector (18).   4) Motor according to one of claims 1   to 3, characterized in that the other collector (18) also comprises a third brush which is connected to the   connection means (-33) and can be coupled in parallel-   the latter or in series by the latter to obtain other rotational speed regimes with the other brushes   manifold (20-24) and armatures (16, l7).