DE10125646A1 - Brushless motor and rotation control arrangement for a brushless motor - Google Patents

Abstract

OBJECT DOLLAR A The invention relates to a rotary control device for a brushless motor which, although simple in construction, can receive position signals in succession by energizing a plurality of sensors by connecting only two signal cables. DOLLAR A Means for solving the task DOLLAR A A position determination circuit (18) is thereby implemented by an impedance change circuit (11), in which several Hall elements provided on a stator and connected in parallel to one another are connected directly to a reference impedance element, and which is designed in such a way that bypass-connected to the individual Hall elements, each with different values, which are switched on and off alternately by the on / off circuit based on the magnetic field of the rotating field, a voltage discrimination circuit (12) which detects the output voltage from the Impedanwechsel circuit (11) discriminated, and an OR circuit (13) is formed, which produces an OR operation of the output voltage from the voltage discrimination circuit (12) and thus outputs a position signal for the rotor.

Description

The present invention relates to a small brushless motor, as shown in the Practice used by doctors and dentists, and on a rotary control device for such a brushless motor.

State of the art

A brushless motor in which the brush, the commutator, of a DC motor and other mechanical contact elements have been removed, and in their place with an electrical commutation mechanism has recently been found in the Practice of doctors and dentists as a small cutter widely used.

In general, in a brushless motor of this kind, energizing turns one around the stator-wound multi-phase coil generates a rotating field, causing rotation as a Permanent magnet trained rotor, the rotational position of the Rotary element are used several position sensors formed from Hall elements.

Such position sensors are in general designed as circuits on one arranged single circuit board and sometimes to a single block summarized, but since all sensors each have a signal output connection, in addition to the power connection and the common connection, the number of sensors accordingly, signal output connections are brought out.

Since signal lines are required according to the number of connections, the number increases with an increasing number of position sensors also the number of signal lines what that Laying the lines is complicated and so productivity during the Assembly and operation as well as the reliability impaired.

Fig. 10 shows three position detection sensors S # 1 to S # 3, which are combined to form a block, the power connections Tv and common connections Tc provided for each sensor being connected together in each case, but the signal output connections T1 to T3 provided for each sensor are brought out separately , so that three signal lines are required in addition to the power cable and the common cable in accordance with the number of sensors, five signal lines being required in the case of connections to other signal processing parts and three signal input connections being required for processing the sensor signals.

Object of the invention

In view of the fact that in a conventional sensor switching part with several Sensors, as described above, the number of signal lines with increasing number of sensors grows and the wiring is complicated, the present invention is the Task based on a brushless motor and a rotary control device for one to offer such a brushless motor in which with a simple construction by Connecting only two signal lines to power multiple sensors Take position signals in sequence.

The object is achieved by a rotation control device for a brushless motor, which has a rotor formed from a magnet, a stator having a coil for applying a voltage for generating a rotating field, and a position detection circuit which contains several Hall elements and is arranged in accordance with the phases of the stator , marked
by an impedance changing circuit for selectively connecting different values of optional impedance elements to a reference impedance element in response to the on / off switching of the Hall elements, so that the resulting impedance can be changed, by switching the individual Hall elements on, the optional impedance elements corresponding to one another be connected in parallel,
by a voltage discrimination circuit for discriminating the output voltage of the impedance changing circuit, for which several threshold values are set to distinguish between combination patterns for the on / off switching of the Hall elements, and by an OR circuit for OR-linking the output voltage from the voltage discrimination circuit, so that the determination the on / off switching of the Hall elements can be carried out synchronously with the phase changes of the phase voltage applied to the stator.

The position detection circuit, which is a feature of this rotation control device, has an impedance changing circuit in which on the stator in correspondence to everyone Phase several Hall elements are arranged in parallel, and around the determined Combination pattern for the on / off switching of the stator, which can be found together with the Rotation of the rotor changes as a signal via two signal lines to the To transmit voltage discrimination circuit, the impedance value of the Circuit of the Hall elements additional connected optional impedance elements is different.

For the voltage discrimination circuit to determine the change in Voltage levels, which are in relation to the on / off circuit pattern of the Hall Elements changed, multiple thresholds provided.

The Hall elements are designed as switching elements, for example as Hall switches, and if the stator is designed as a three-phase coil, there are six per pair of poles Combination pattern for the on / off switching.

The output voltage discriminated by the voltage discrimination circuit can only the combination pattern for the on / off switching of the Hall elements distinguish, but not which of the Hall elements is currently activated and which is deactivated. Therefore, you can not only because of this output voltage Voltage discrimination circuit make a rotation control of the motor.

Therefore, there is an OR circuit here, which ORs the Output voltage of the voltage discrimination circuit requires and the determination of  Turns the Hall elements on or off. This is done from the output voltage the voltage discrimination circuit, taking into account the position which the Preset angles in electrical degrees of the Hall elements on the stator corresponds, and the phase sequence change of the voltage applied to the stator, one Output voltage set to create the OR link and so the Position detection voltage, that is, a position signal.

The position signal obtained from the position determination circuit is used together with the signal of the phase voltage applied to the stator to the coil drive circuit issued and causes the rotation control of the motor.

It is therefore sufficient with the help of this rotation control device, on the live one Circuit board of the brushless motor stator Hall elements and Attach optional impedance elements, so that the training is easy and another Reduction of the brushless motor can be achieved. Leading out is also sufficient of two signal lines from the impedance change circuit, that is to say from the stator.

The rotary control device for a brushless motor according to claim 2 is one Rotary control device according to claim 1, characterized in that for the Voltage discrimination circuit is the threshold of the predetermined pattern the on / off switching of the Hall elements and the threshold values for short circuit and Shutdown are adjustable.

In such a rotation control device, the voltage discrimination circuit is as Multi-level wind comparator, in which several threshold values are set. In the event that six different patterns of on / off Circuit combinations result, there are also patterns for the short circuit and Switching off, so that a total of eight operating patterns can be determined.  

The rotary control device for a brushless motor according to claim 3 is one Rotary control device according to one of claims 1 or 2, characterized in that the stator has a current-carrying circuit board, and that on this current-carrying Circuit board for the selection impedance elements and the Hall elements Switches with pins are attached.

In such a rotation control device protrude from the stator Elective impedance elements and Hall switches containing Hall elements led out Connection pins from openings formed in the current-carrying circuit board and are effectively attached by soldering, so that in the formation of the coil and at There is little waste in an autoclave treatment.

The rotation control device for a brushless motor according to claim 4 is one Rotary control device according to one of claims 1 to 3, characterized in that the reference impedance elements and the selective impedance elements are resistors and that for the case that the stator is three-phase, the choice impedance elements different Resistance ratios of 1: 1.6-2.2: 4-5.

The appropriate quotients of different resistance values are for one Rotary control device have been experimentally determined, which is why Rotary control device with the effect of the present invention without difficulty can be achieved.

The rotation control device for a brushless motor according to claim 5 is one Rotary control device according to one of claims 1-4, characterized in that the Voltage discrimination circuit and the OR circuit formed as a microcomputer are.

For this reason, the control device can be made compact.  

The brushless motor according to claim 6, which is provided by the rotation control device for one brushless motor is subjected to a rotary control according to one of claims 1-5 characterized in that several Hall elements and inside the brushless motor Elective impedance elements are attached.

Are in the case of using a rotation control device according to the present Invention provided several Hall elements and optional impedance elements on the stator the structure of the brushless motor is simplified, and because the number of out of the Stator-guided signal lines is two, the effect of such a brushless Motors fully exhausted.

However, the arrangement of the Hall elements and the elective impedance elements does not have to the stator may be limited, but they can also be placed in any suitable location inside the brushless motor can be provided, and since in this case, the number of components is small, the structure of the brushless motor is still simple.

The brushless motor according to claim 7, which is provided by the rotation control device for one brushless motor is subjected to a rotary control according to one of claims 1-5 characterized in that inside one adjoining the brushless motor Tube connector or inside one between the brushless motor and the Tube connector part provided several Hall elements and adapter Elective impedance elements are attached.

The arrangement of the Hall elements and selective impedance elements described above must be not be limited to the inside of the brushless motor, but they can also be in a nearby tube connecting part may be provided, and since in this case also The number of components is small, the construction of the tube connecting part is still simple.  

You can also put one between the brushless motor and the inside Tube connector part provided adapter, and since in this case the Structure of the adapter is simplified and also in a conventional brushless motor by adding an adapter Hall elements and Optional impedance elements can be added according to the present invention thus achieved the use of a rotary control device according to the present invention become.

embodiments

The present invention is to be explained below with reference to the figures.

Fig. 1 is a block diagram schematically of the present invention showing the basic structure of a rotation control device for a brushless motor.

The rotation control device 20 is composed of a rotor (mentioned below) and a stator, and, in terms of control, has a brushless motor 10 provided with an impedance changing circuit 11 , and a voltage discrimination circuit 12 which is provided by two signal lines leading from this brushless motor 2 fa receives a voltage signal to detect the change in voltage level, and an OR circuit 13 for receiving a discrimination signal and for calculating the position signal of the rotor of the brushless motor 10 , and a coil drive circuit 15 which provides a stator of the brushless motor 10 Drives the coil.

If the stator of the brushless motor 10 is three-phase, three coils are provided on the stator in this exemplary embodiment, and the three drive lines 2 fb, which supply drive current to these three coils, connect the brushless motor 10 to the coil drive circuit 15 .

In such a rotary control device 20 , as will be explained in more detail later, a plurality of Hall elements, that is to say position sensors for the rotor, are provided on the stator of the brushless motor 10 , two signal lines 2 fa being sufficient here and by the processing of the signals from FIGS Signal lines 2 fa are obtained by the voltage discrimination circuit 12 and the OR circuit 13 for a position signal for the rotor, by means of which the rotation of the brushless motor 10 is controlled in the coil drive circuit 15 by supplying drive current from the three drive lines 2 fb to the coils of the stator becomes.

This means that regardless of the number of phases of the stator, two signal lines 2 fa are sufficient, but the drive lines 2 fb correspond to the number of phases, so that in the case of three-phase, five input or output lines are sufficient for the brushless motor 10 , i.e. for the stator ,

In addition, the impedance changing circuit 11 described above, the voltage discrimination circuit 12 and the OR circuit 13 are combined to form a position determination circuit 18 , wherein the voltage discrimination circuit 12 and the OR circuit 13 can be formed by a microcomputer 19 , so that a compact control device can be obtained in this way receives.

Fig. 2 is a block diagram schematically showing the structure of the essential parts of a rotation control device of a brushless motor according to the present invention including the position detection circuit. Parts already explained have the same reference number as before and will not be explained a second time.

The position detection circuit 18 includes the impedance changing circuit 11 , the voltage discrimination circuit 12 and the OR circuit 13 .

Here, the impedance change circuit 11 is designed such that, corresponding to the three Hall switches Hu, Hv, Hw and in response to the three resistance elements Ru, Rv, Rw which correspond to the three resistance elements Ru, Rv, Rw and are provided as optional impedance elements Circuit of the Hall elements, the resistance elements Ru, Rv, Rw are switched off in parallel and thus their parallel resulting resistance can be changed, as a result of which the level Vh of the voltage signal input by the impedance change circuit 11 into the voltage discrimination circuit 12 (i.e. the divided voltage of the parallel circuit to the selection impedance) of the circuit, which is designed as a parallel resulting circuit of reference impedance elements and selection impedance elements) changed in accordance with the on / off combination pattern of the Hall elements.

However, strictly speaking, there is no on / off switching for the Hall elements made, but designed as transistors and built into the Hall switch Switch elements receive the output power of the Hall elements and thus switch on and from.

For Fig. 2 it is assumed as an example that a three-phase rotating field is applied to the stator and the rotor is set in rotation, and since the three Hall elements are arranged on the stator according to an angle in electrical degrees, the two ones come / Off combination patterns, in which all Hall switches Hu, Hv, Hw are on or off, are not in front, and as shown in FIG. 3b, six different on / off combination patterns can be used according to the rotational position of the rotor result.

The voltage discrimination circuit 12 contains a multilevel wind comparator made up of ten comparators CP1-CP10 connected in parallel, five in the respective reference input connection of the comparators CP1-CP10 being formed with the aid of another resistor R1-R9 connected in series from nine to another constant voltage current source Partial voltage circuit certain reference voltages Vh1-V5 are input (as can be seen in Fig. 4, Vh1-Vh5 are set according to the size of their values), and the other signal input terminal is connected and inputs the voltage signal Vh from the impedance changing circuit 11 .

The output terminals of the ten comparators CP1-CP10) are connected to the OR circuit 13 so that the on-off signals of the three Hall switches Hu, Hv, Hw are ORed in correspondence with the phase sequence changes of those applied to the stator Phase voltage is established.

That is, the OR circuit 13 is formed by three OR gates OR1-OR3, the on-off controls of the three Hall switches Hu, Hv, Hw corresponding to the phase sequence change of each of the three OR gates OR1-OR3 phase voltage applied to the stator can be demodulated.

The combination pattern, for which an OR operation is to be established in this case, is determined taking into account the on / off switching of the three Hall switches Hu, Hv, Hw, that is, if, for. B. the off circuit is observed, then an OR operation with respect to the Hall switch Hu, which is based on the determination of patterns 1, 2 and 6 by the voltage discrimination circuit 12 , an OR operation with respect to the Hall switch Hv, which is based on the determination of patterns 4, 5 and 6 by the voltage discrimination circuit 12 , and with respect to the Hall switch Hw an OR combination which is based on the determination of patterns 2, 3 and 4 by the voltage discrimination circuit 12 , and so on the on / off switching of the Hall elements contained in the three Hall switches Hu, Hv, Hw is demodulated.

Since the output power, from which an OR operation is to be established by the OR circuit 13 , depends on the structure of the brushless motor, that is, on the number of poles of the rotor and on the phase pattern of the voltage which is applied, around the stator with a rotating field equip, is different, of course, the structure of the OR circuit must be changed to match the structure of the impedance changing circuit and the voltage discrimination circuit.

Reference number 14 relates to a switch-off / short-circuit detection circuit in which two comparators CP10, CP11, whose standard voltage Vh0, Vh6 (here Vh0 <Vh1, Vh6 <Vh5) are different, are connected in parallel, and which evaluates the voltage signal Vh from the impedance change circuit 11 and determines whether the impedance changing circuit 11 including the Hall switches Hu, Hv, Hw has a shutdown or a short circuit.

The brushless motor is three-phase, which is why three coils Cu, Cv, Cw are provided on its stator 2 in this embodiment.

The output voltage, which is discriminated by the voltage discrimination circuit, only distinguishes which on / off combination patterns are available for the Hall switches Hu, Hv, Hw, but cannot differentiate which of the Hall elements is currently activated. Therefore, the output voltage Vh of the voltage discrimination circuit 12 cannot be used to control the rotation of the motor alone.

An OR operation of the output voltage Vh from the voltage discrimination circuit 12 is thus carried out by means of the OR circuit 13 and the on / off circuit of the Hall switches Hu, Hv, Hw is determined. For this purpose, a position signal is obtained from the OR circuit 13 by the distribution of the Hall switches Hu, Hv, Hw on the stator 2, as well as the phase sequence changes of the output voltage Vh from the voltage discrimination circuit 12, which is set in advance and corresponds to an angle in electrical degrees voltage applied to the stator are taken into account.

The position signal determined with the aid of the position determination circuit 18 is output to the coil drive circuit 15 and the rotation control of the motor is thus carried out.

Because of this rotary control device 20 , only the selection impedance elements Ru, Rv, Rw have to be provided for the stator 2 in addition to the Hall switches Hu, Hv, Hw, so that the structure is simplified and the brushless motor can be made more compact. It is also sufficient to lead only two signal lines out of the impedance change circuit 11 , that is to say out of the stator 2 .

I I1-I6 in FIG. 2 denotes a resulting current which, when the selection impedance elements Ru, Rv, Rw are switched on, flows from the Hall elements contained in the three Hall switches Hu, Hv, Hw in accordance with the rotational position of the rotor Electoral streams composed of Iru, Irv, Irw. As already mentioned, when a rotating field is generated on the two-pole rotor by the stator to which a three-phase AC voltage is applied, six types of values result in accordance with the on / off circuit patterns of the Hall switches Hu, Hv, Hw I1-I6.

Here, Vo is the partial voltage of the reference impedance element Ro, Vh the partial voltage of the resulting parallel circuit of the optional impedance elements, which are optionally connected in parallel by the Hall switches Hu, Hv, Hw (this is the partial voltage that is output from the impedance change circuit 11 to the voltage discrimination circuit 12 ) and Vc is the resulting voltage which is supplied to the impedance changing circuit, the relationship between the output currents I I1-I6 and the partial voltage Vo, the partial voltage Vh and the resulting voltage Vc being as follows:

Vo = I (11 ~ I6) * Ro

Vh = Vc * Vo

I1 = Rv * Rw (2 * I on + I off + Irv + Irw) / {Rv * Rw + Ro * (Rv + Rw)}

I2 = Rv * (2 * I on + I off + Irv) / (Ro + Rv)

I3 = Ru * Rv (2 * I on + I off + Iru + Irv) / {Ru * Rv + Ro * (Ru + Rv)}

I4 = Rv * (2 * I on + I off + Iru) / (Ro + Ru)

I5 = Ru * Rw * (2 * I on + I off + Iru + Irw) / {Ru * Rw + Ro * (Ru + RwI)}

I6 = Rw * (2 * I on + I off + Irw) / (Ro + Rw)

Iru = (Vc - Vo) / Ru

Irv = (Vc - V o) / Rv

Irw = (Vc - Vo) / Rw

The sign (*) stands for multiplication, while the sign (/) stands for division.

(I on) and (I off) show the current consumption of the Hall switches Hu, Hv, Hw, and how out the formulas shown above, (I on) and (I off) should not be from the Partial voltage Vh dependent and also compared to the currents Iru, Irv, Irw der Elective impedance elements may be smaller.

Fig. 3 (a) shows a construction example of the constituent elements of the impedance conversion circuit, while Fig. 3 (b) shows the six on / off combination patterns which result when a three-phase voltage is applied to a two-pole rotating element which is connected to the one shown in Figs 3 (a) is constructed based on a design, a rotating field is generated and the output current used and flowing to the impedance conversion circuit is brought into correspondence with the on / off switching of the three Hall elements Hu, Hv, Hw.

Fig. 4 (a) shows how the voltage discrimination circuit distinguishes the on / off combination patterns of the Hall elements, in which figure the output of the impedance conversion circuit is represented not as voltage but as converted into electric current. (Vh1-Vh5) form thresholds for discriminating the six activation patterns of the Hall elements, while Vh0 forms a threshold for a short circuit and Vh6 forms a threshold for switching off. (b) shows a pattern discrimination signal output from the voltage discrimination circuit, and (c) shows the output voltage of the three Hall switches Hu, Hv, Hw demodulated by the OR circuit.

The OR circuit 13 , in the form shown below, represents an OR operation of the output voltage from the voltage discrimination circuit 12 and then outputs an output voltage as a position signal as shown in FIG. 4 (c).

Hu = V (16) + V (14) + V (15)

Hv = V (15) + V (11) + V (13)

Hu = V (13) + V (12) + V (16)

The diagram shown in FIG. 5 shows the relationship between the on / off switching of the Hall elements contained in the Hall switches and the change in position of the rotor and the stator, the rotor 1 , as in FIG Shown arrow, rotates counterclockwise and where the on / off switching of the Hall elements changes and the combination pattern as shown in Fig. 3 (b) assumes.

In the present invention, such on / off circuit patterns of Hall- Elements used to control the rotation of a brushless motor by first in Corresponding to the Hall elements provided selection impedance elements Ru, Rv, Rw due to the on-switching of the Hall elements and the Changing the values of their parallel resulting resistances as changing the  Output voltage Vh is determined and then further processing in the Voltage discrimination circuit and the OR circuit is made and the respective on or off switching state of the Hall elements in correspondence to Phase sequence change of the phase voltage which is applied to the stator, is demodulated, and by this demodulated on / off signals the position of the rotor in the Relationship to the stator is determined.

With the various resistance values of the choice impedance elements Ru, Rv, Rw it is advantageous that what is obtained by turning the Hall elements on parallel connected resistance values, neighboring values so far from each other are distant that they can be sufficiently distinguished from one another.

An experiment by the inventor shows that this can be achieved if this Resistance values can be set with a quotient of 1: 1.6-2.2: 4-5.

Fig. 6 shows the thawing of a pin-mounted power supply circuit for the stator.

As is clear from this figure, it is sufficient if in this rotary control device the selection impedance elements Ru, Rv, Rw and the Hall switches Hu, Hv, Hw containing the Hall elements are attached to the stator 2 , which results in an extremely simple construction ,

In addition, a mere attachment to the circuit board 2 d is sufficient, but a flat attachment is unnecessary, so that the connection pins led out of the selection impedance elements Ru, Rv, Rw and from the Hall switches Hu, Hv, Hw are formed in the circuit board 2 d The openings protrude and are fixed by soldering, which is why there is little waste when shaping the coil and during an autoclave treatment.

Also, as shown in FIG. 6, only a total of five connections 2 f are led out of the printed circuit board 2 d of the stator 2 , namely, on the one hand, the two connections 2 fa of the signal lines from the selection impedance elements Ru, Rv, Rw and the Hall switches Hu , Hv, Hw, and on the other hand the three connections 2 fb for the drive lines of the three-phase coil.

The reference number 2 b placed in parentheses after the reference symbols Hu, Hv, Hw has been added in relation to the hard-formed component of the Hall switches Hu, Hv, Hw.

Fig. 7 shows a perspective, partially sectioned outer view of an embodiment according to the present invention.

The stator 2 is three-phase, and it is formed from three coils 2 a for generating the rotational force, that is, the rotating field, from Hall switches 2 b for detecting the magnetic field of rotor 1 , from a coil body 2 c, which is the inner circumference of the stator 2 forms, and from a current-carrying circuit board 2 d, which is provided at the rear end of the coil former 2 c (on the right side of the figure) perpendicular to the axial longitudinal direction of the stator 2 , that is to say in the outer circumferential direction, and from which a connection 2 f emerges , and has the feature that these coils 2 a, the Hall switch 2 b, the bobbin 2 c and the circuit board 2 d are integrally coated by a resin 2 e.

The bobbin 2 c is a straight tube, and between its inner diameter and the outer diameter of the rotor 1 , a gap is provided so that the rotation of the rotor 1 is not hindered, and around its outer wall are those for generating a rotating field for the permanent magnet of the rotor 1 certain coils 2 a wound, at the rear end of the circuit board 2 d is provided.

The coils 2 a are formed by the press spooling method along the outer wall of the coil body 2 c, in this embodiment the coils 2 a formed in this way are wound side by side around the outer circumference of the coil body 2 c, which is divided into three equal sections, only three coils being used for this reason because it is a three-phase brushless motor. The number of coils need not be limited to three.

In the press winding process, a copper or other highly conductive material is used formed self-adhesive wire wound with a bobbinless wire winding device and at the same time exposed to hot air, which sticks the wires together, after which the wound and adhesive coil is inserted into a pressed metal mold through the coil electrical current is conducted, which heats them and makes them flexible, whereupon they are then pressed is and so a coil of the desired shape can be made, the special Characteristic is that springs are used above and below the metal mold are so that great pressure is not suddenly exerted during the pressing process, but the pressure force can be regulated by the springs.

In this way, no residual clamping force remains in the coil formed in this way, and one can Coil of the desired shape, in particular a thin coil in the radial direction, the can also be wound evenly around the rotor, forming a coil So that as a coil for a brushless motor that has a small outside diameter should have is advantageous.

The Hall elements 2 b are heat-resistant from the start, but their heat resistance is further enhanced by the resin coating, so that the resistance of the entire brushless motor to sterilization by autoclave treatment is further enhanced. In addition, since the Hall elements detect the rotation of the rotor when changing the pole of the magnetic flux, they are sensitive to a change in the magnetic flux, but their position has been given sufficient consideration so that the magnetic field of the coil has no influence on them and they affect them Can function sufficiently.

Fig. 8 shows an exploded perspective view of a brushless motor according to the present invention.

This brushless motor 10 is formed from the rotor 1 , which is provided on its rotor shaft 1 b with a permanent magnet 1 a and on its two sides with the shaft bearings 1 c, 1 f, with an outer sleeve 4 , which on the one hand rotates the rotor 1 supports and on the other hand receives the entire brushless motor 10 , from a core unit 3 , which is contained in the outer sleeve 4 and contains a core, not shown, made of magnetic material, from a core unit 3 contained in this, provided with a coil stator 2 , from a on the rear side (on the right side of the figure) of the stator 2 and the outer sleeve 4 fitted rear support 5 and from a central support 6 for connecting the rear support 5 and the connecting part of the main body side.

The permanent magnet 1 a of the rotor 1 is provided on the rotor shaft 1 b, and its outer wall is covered. Of the shaft bearings 1 c, 1 f provided on both sides of the permanent magnet 1 a, the front shaft bearing 1 c (left side of the figure) has a larger outer diameter than the rear shaft bearing 1 f. The outer diameter of the shaft bearing 1 c is larger than that of the permanent magnet 1 a.

The shaft bearing 1 c is fitted into the front shaft bearing opening 4 a of the outer sleeve 4 , and the permanent magnet 1 a is accommodated inside the stator 2 , and since the shaft bearing 1 f is fitted into the shaft bearing opening 5 a of the rear support 5 a, they correspond Inner diameter of the shaft bearing opening 4 a of the outer sleeve 4 , the stator 2 and the shaft bearing opening 5 a each other.

This results in a simplified installation and removal, in that the core unit 3 , the stator 2 , the rear support 5 , etc. are inserted into the outer sleeve 4 and the rotor 1 is inserted from the front in connection with the shaft bearings 1 c, 1 f and removed again can be. Since the wear of the shaft bearings 1 c, 1 f of the rotor 1 is particularly high depending on the use, it is extremely practical for the repair change if, without taking apart other parts, the rotor 1 is connected to its shaft bearings 1 c, 1 f from the can remove brushless motor.

At the top of the rotor shaft 1 b of the rotor 1 is a clutch 1 i for transmitting the torque to a medical device, for. B. on the shaft of a handpiece, provided, the inner diameter of the shaft bearing 1 c on the side of this coupling 1 i is larger than the outer diameter of the coupling 1 i. So if you have removed the rotor shaft 1 b connected to the shaft bearings 1 c, 1 f, and then exchanged the shaft bearing 1 c on the side of the clutch 1 i, you can also remove the old shaft bearing 1 c and without removing the clutch 1 i attach a new shaft bearing 1 c, so that the shaft bearings are easy to replace during repairs.

Stabilizers 1 j, 1 k are provided between the permanent magnet 1 a provided on the rotor shaft 1 b and the shaft bearings 1 c, 1 f delimiting them on both sides. These stabilizers 1 j, 1 k are made of easily cut metal such. B. formed brass and attached to the rotor shaft 1 b, wherein the vibration balance of the rotor 1 can be achieved by suitable cutting away part of them. In this way, an adequate vibration balance can be established, and even when the rotor 1 is rotated rapidly, vibrations based on a poor balance do not occur, so that the rotor 1 is suitable as a rotary drive means for medical devices.

Of the stator 2 with the special feature that it contains a coil and is integrally coated with resin, only the integrally molded resin coating 2 e can be seen from the outside in FIG. 7. This one-piece resin coating is made separately from the assembly of the entire brushless motor 10 so that when using a certain medical tool or the like, the shaft center of the inside and outside diameters match. At the rear end of the stator 2, the connections 2 f protrude, and even when the rear support 5 is attached to the stator 2 , these connections 2 f protrude from the rear support 5 , so that an electrical connection can be made.

The core unit 3 fulfills the role of an iron core for strengthening the magnetic field of the coil of the stator 2 , the outer wall and the two sides of the core (not shown) made of stacked annular silicon steel sheets being connected by a core sleeve 3 c. The two lines 3 c visible on the outer wall of the core unit 3 serve to convey the water and air required for dental treatment from the main body (right side of the figure) to the front (left side of the figure, ie the turning tool), which is why they are milled into Grooves 3 b are embedded, which penetrate the outer wall of the core sleeve 3 h in the axial direction, and are attached to the outside by the outer sleeve 4 to a limited extent.

In the present exemplary embodiment, the milled grooves 3 b are provided at four locations in the outer wall of the core sleeve 3 h, and the remaining two milled grooves 3 b are used for embedding lines (not shown). In this way, necessary fluids can be conveyed without creating an unnecessary gap between core unit 3 and outer sleeve 4 , so that the present brushless motor fulfills the requirement of small size and is therefore suitable as a rotary drive means for manually operated medical devices during surgical interventions.

The core unit 3 and the stator 2 are, as shown in the figure, separate, detachable and re-attachable units, so that, in contrast to one-piece designs, one of the two elements can be replaced, which simplifies the repair and minimizes costs ,

On the front of the outer sleeve 4 , as previously mentioned, a shaft bearing opening 4 a is provided in front of the rotor 1 for receiving the shaft bearing 1 c, which, although this cannot be seen in the figure, is open towards the rear. In the front conversion edge of the shaft bearing opening 4 a, line bores 4 b are also formed so that when the core unit 3 is received in the outer sleeve 4, the lines 3 c etc. protrude from these line bores 4 b.

In the rear support 5 are the shaft bearing opening 5 a for receiving the rear shaft bearing 1 f of the rotor 1 , openings 5 b for letting the connections 2 f of the stator 2 protrude to the rear after this after inserting the core unit 3 and the stator 2 in the outer sleeve 4, the rear support 5 has been placed, and line bores 5 c, which, like the line bores 4 c of the outer sleeve 4, allow the lines 3 c, which are embedded in the milled grooves 3 b of the core unit 3, to protrude.

Two external threads with different thread pitches are formed on the outside diameter of the center support 6 . The external thread 6 a shown on the left in the figure, that is to say the one arranged on the front of the brushless motor, is brought into engagement with the outer sleeve 4 and has the task of the core unit 3 , the stator 2 , the rear support 5 etc. in the outer sleeve 4 to fix. The external thread 6 b attached to the rear of the brushless motor is used for connection to a flexible tube (not shown) for conveying electricity, water, air, etc.

In the present brushless motor 10 , as can be seen from the figure, the rotor 1 is inserted from the front of the outer sleeve 4 (right side of the figure), while the core unit 3 , which contains the lines 3 c etc., is inserted one after the other Resin-coated stator 2 and the rear support 5 from the rear of the outer sleeve 4, the assembly is completed, whereby the centering of the rotor 1 and stator 2 is unnecessary and thus the entire assembly of the brushless motor is simplified.

The entire stator 2 is integrally covered with resin, and there thus takes place at the Außenumwandung of the stator 2 no exposure of the coil etc., this is not damaged during the fitting of the stator 2 in the core unit. 3 As a side effect, the poor heat resistance of the stator 2 is improved due to the insulating property of the resin, and thus the heat resistance of the entire brushless motor is increased.

Fig. 9 shows a partially sectioned front view of another embodiment of a brushless motor according to the present invention.

This figure shows a handpiece body B with a built-in brushless motor 10 , to which a handpiece A is attached.

This handpiece body B is a presence of a brushless motor 10, a tubular connecting part of Ba with motor 10 and detachably connected, this motor 10 with electricity, water, air, etc. supplied flexible tube C), a tool connecting part 7 and a provided on the tool connection part 7 One-touch engagement means 7 a, by means of which the attachment and detachment of the hand part (A) can take place in the one-touch method.

FIGS. 6, 7 represent an embodiment in which the essential components of the rotational control apparatus according to the present invention, namely the choice of impedance elements Ru, Rv, Rw and the Hall elements containing Hall switch Hu, Hv, Hw, the stator 2 are provided, but these can include the selection impedance elements and the Hall elements Hall switches also at any other suitable location of the brushless motor 10 , and since only a few components are required in this case as well, the structure of the brushless motor is also then 10 easy.

In this case, it can be attached to the brushless motor 10 in one piece without using an overhead line or printed circuit board on the stator.

Also, the selection impedance elements and the Hall switches do not have to be inside the brushless motor, but can also be found in the nearby Pipe connection part Ba can be provided, which at the end of the attachable to the engine and  of which removable tube C is provided, but in this case only a few Components are necessary and the construction of this tube connection part is simple.

In addition, an arrangement inside an adapter (not shown) provided between the brushless motor 10 and the tube connecting part Ba is possible, in which case not only the construction of this adapter is simple, but also for a conventional brushless motor by adding this adapter Hall elements and the select impedance elements according to the present invention can be added and a rotation control device according to the present invention can be used.

Advantages of the invention

Using the rotary control device for a brushless motor according to claim 1 it is sufficient for the stator of the brushless motor except for the Hall elements Provide election impedance elements, which results in a simple structure and one Reduction of the brushless motor can be achieved. Leading out is also sufficient of two lines from the impedance conversion circuit, that is from the stator.

Using the rotary control device for a brushless motor according to claim 2 can, in addition to the effect of the invention disclosed in claim 1, if the Voltage discrimination circuit from a multi-level wind comparator for several threshold values have been set, and six are made up of three Hall Combination patterns for the on / off switching resulting from elements by which Add a short circuit and a shutdown pattern to a total of eight Determine the combination pattern.

Using the rotary control device for a brushless motor according to claim 3 can, in addition to the effects of those disclosed in any of claims 1-2  Invention, which occurs when the coil is formed and during an autoclave treatment Keep the committee low, since they each consist of the electoral impedance elements and the Hall pins containing Hall elements lead out through connecting pins in the projected openings protrude from the circuit board and soldered are effectively attached to the stator.

Using the rotary control device for a brushless motor according to claim 4 can, in addition to the effects of those disclosed in any of claims 1-3 Invention, without difficulty to produce a rotary control device which the Effect of the present invention achieved because the appropriate ratio of the different Resistance values of the choice impedance elements to each other have been determined experimentally.

Using the rotary control device for a brushless motor according to claim 5 can, in addition to the effects of those disclosed in any one of claims 1-4 Invention to make the control device more compact because the Voltage discrimination circuit and the OR circuit formed as a microcomputer are.

With the help of the brushless motor according to claim 6, one can by one Rotary control device according to the present invention, and by using Stator provides several Hall elements and optional impedance elements, the structure of the stator of the brushless motor and simplify with just two Signal lines get out of the stator.

The Hall elements and the selective impedance elements need not be limited to the stator remain and can also be provided at a suitable location inside the brushless motor and since only a few components are required in this case, the structure is also of the brushless motor is still simple.  

With the help of the brushless motor according to claim 7, one can by one Rotary control device according to the present invention uses the Hall elements and the choice impedance elements not only inside the brushless motor, but also provide in the nearby pipe connection part, and there are only a few in this case Components are required, the structure of the tube connection part is still as before simple.

It is also possible to use these Hall elements and optional impedance elements inside between the brushless motor and the tube connecting part to provide, in which case not only the construction of this adapter is simple, but even for a conventional brushless motor by adding this adapter Hall elements and the select impedance elements according to the present invention can be added and a rotation control device according to the present Invention can be used.

Brief explanation of the drawings

Fig. 1 is a block diagram schematically of the present invention showing the basic structure of a rotation control device for a brushless motor.

Fig. 2 is a block diagram schematically showing the structure of the essential parts of a rotation control device of a brushless motor according to the present invention including the position detection circuit.

Fig. 3 (a) shows a table with the various properties of the impedance changing circuit, (b) shows a table of its activation patterns.

Fig. 4 (a) shows the output voltage of the impedance changing circuit, (b) shows the output voltage of the voltage discrimination circuit, and (c) shows the output of the OR circuit.

Fig. 5 explains the relationship between the on / off switching of the Hall switches and the position change of the rotor and the stator.

Fig. 6 explains the structure of the current carrying circuit for the stator which is attached with pins.

Fig. 7 is a perspective, partially sectioned external view showing an embodiment of the stator according to the present invention.

Fig. 8 shows an exploded perspective view of the brushless motor according to the present invention.

Fig. 9 shows a partially sectioned front view of another embodiment of a brushless motor according to the present invention.

FIG. 10 shows an example of wiring multiple sensors of a conventional brushless motor rotation control device.

reference numeral

1

rotor

2

stator

2

b (Hu, Hw, Hv) Hall switch

2

d circuit board

2

f pin connector

10

brushless motor

11

Impedance changing circuit

12

Spannungsdiskriminationsschaltung

13

OR circuit

14

Shutdown / short detection circuit

15

Coil drive circuit

18

Position detection circuit

19

microcomputer

20

Rotation control device
R0 reference impedance element
Ru, Rv, Rw election impedance element
SW1-SW3 Hall elements

Claims (7)

1. A rotary control device for a brushless motor, which has a rotor formed from a magnet, a stator having a coil for applying a voltage for generating a rotating field, and a position detection circuit containing a plurality of Hall elements and arranged according to the phases of the stator, characterized by a Impedance change circuit for selectively connecting different values of optional impedance elements with a reference impedance element in response to the on / off switching of the Hall elements, so that the resulting impedance can be changed, with the individual impedance elements being connected in parallel by mutually connecting the individual Hall elements become,
by a voltage discrimination circuit for discriminating the output voltage of the impedance changing circuit, for which a plurality of threshold values are set to distinguish between combination patterns for the on / off switching of the Hall elements and
by an OR circuit for OR-linking the output voltage from the voltage discrimination circuit so that the on / off circuit of the Hall elements can be determined synchronously with the phase changes of the phase voltage applied to the stator. 2. Rotary control device for a brushless motor according to claim 1, characterized characterized in that for the voltage discrimination circuit, the threshold of the im Predictable combination pattern for the on / off control circuit of the Hall Elements and the threshold values for short circuit and switch-off are adjustable.   3. A rotary control device for a brushless motor according to one of claims 1 and 2, characterized in that the stator has an electrical circuit board, and in that this electrical circuit board, the selection impedance elements and the Hall elements containing Hall switches are attached with pins. 4. A rotary control device for a brushless motor according to any one of claims 1 to 3, characterized in that the reference impedance elements and the selection impedance elements Resistors are and that in the event that the stator is three-phase, the Choice impedance elements different resistance value quotients from 1: 1.6-2.2: 4-5 exhibit. 5. A rotary control device for a brushless motor according to any one of claims 1 to 4, characterized in that the voltage discrimination circuit and the OR Circuit are designed as a microcomputer. 6. Brushless motor by the rotary control device for a brushless motor is subjected to a rotary control according to one of claims 1 to 5, thereby characterized in that several of the Hall elements and inside the brushless motor Choice impedance elements are mounted. 7. Brushless motor operated by the rotary control device for a brushless motor is subjected to a rotary control according to one of claims 1 to 5, characterized characterized in that adjoining the brushless motor Tube connector or in one between the brushless motor and the Tube connector provided several of the Hall elements and adapters Choice impedance elements are mounted.