DE10236700B4 - Device for holding and fixing a sensor device in a DC motor - Google Patents

Abstract

Device for holding and positioning a sensor device (46) relative to a signal generator in a DC motor, wherein the DC motor comprises a rotor assembly (18), a stator assembly (12), the sensor device (46) and a flange (10) or a base plate for mounting the Having DC motor, characterized by
a) a support plate (70) made of sheet metal, on which the sensor device (46) is mounted and which serves as a conclusion for the sensor device, and
b) a receiving device (76, 76 ') for receiving the carrier plate (70),
c) said receiving means (76, 76 ') including a groove or pocket formed on said flange (10) or base plate and having a fixed spatial relationship with said transducer;
d) the sensor device (46) is connected to a ribbon cable (50) attached to the carrier plate (70), and
e) the carrier plate (70) with the sensor device (46) and the ribbon cable (50) is pressed into the groove or pocket.

Description

The The invention relates to a device for holding and fixing a sensor device in a DC motor according to the preamble of Claim 1.

The This invention relates generally to the field of electronically commutated, brushless DC motors used as internal rotor motors or external rotor motors can be configured. In particular, the invention relates to an internal rotor motor with a shaft, a rotor assembly having one or more arranged on the shaft Permanent magnet having, and with a stator assembly, the one e.g. comprising stator bodies and phase windings constructed of sheets. Two Bearings are at axial distance on the shaft, on the same side of the / Rotor magnets arranged to the rotor assembly relative to the stator assembly one-sided store. This engine design, in which the storage of Wave exclusively done on one side of the rotor assembly, is also called cantilever design designated. The engine according to the invention comprises Further, a sensor device for detecting a size, the is based on rotational position, speed and / or torque of the rotor assembly relative to the stator assembly. The sensor device comprises, for example a position sensor.

Of the DC motor according to the invention is for Automotive applications, e.g. in support of the Steering or for driving a cooling water pump of a motor vehicle. Such Engines come often in the engine room, where they are exposed to high ambient temperatures, Pollution, spray and the like and strong vibrations are exposed. The engines have to therefore protected against these external influences and preferably be robust.

unilaterally stored engines are common constructed so that the Shaft is mounted in a motor flange. The free end of the shaft and thus the rotor is a frontal cover of the engine facing, in which there are connections for power supply and signal lines are located. Electronically commutated DC motors usually have a sensor for detecting the rotational position of the Rotor relative to the stator on, from the commutation signal derive. For single-sided motors, this sensor is in State of the art usually attached to the free rotor end of the motor, since this is freely accessible, next to the external connections is located and therefore allows easy installation.

at On one side mounted motors, however, the problem arises that mounting tolerances can sum at the free end of the motor shaft, so that at this free end of a significant deviation of the actual position of the shaft from its nominal position in radial direction can occur. Furthermore, the free end of Shaft significantly deflected by lateral loads and vibrations become. The influences, which affect the position of the shaft in the radial direction Among other things, the radial play of the bearings, the gap of the bearing seats, a gap change due to temperature fluctuations, a bending of the flange as well as the bending of the shaft.

From The applicant of the present patent application is therefore in a parallel patent application of the same filing date, entitled "DC motor" proposed Sensor device in the area of the shaft between the two bearings to arrange. The two bearings are in particular in a flange or a base plate of the engine mounted with a front end the stator assembly is connected. For installation of the sensor device a position for the sensor system was found between the two camps, at the least positional deviations of the shaft in the radial direction occur.

Thereby However, the problem arises that the sensor device removed from the external motor connections trapped between the two bearings and is poorly accessible. In another patent application of the same Applicant with the same Filing date and title is proposed, the sensor device and the connection device via a flexible ribbon cable, a so-called flex cable, between the outer circumference of the stator body and the inside of the motor housing guided should be, to connect.

DE 43 26 391 A1 discloses a rotation detecting device for a commutator motor, wherein a Hall sensor and a resistor are arranged on a holder plate, which is arranged as Einschiebeteil in a recess of the bearing plate of the engine.

DE 197 10 015 A1 discloses a motor with speed tapping via a Hall sensor, wherein the Hall sensor is arranged on a circuit board and the circuit board with solder pins or contact shoes and is integrated in a component of the motor and contacts, supply and signal lines for the circuit board in the Component of the engine injected and / or plugged.

DE 299 01 967 U1 discloses an electric motor with an arrangement for speed monitoring, wherein the arrangement for Drehzahlüberwa a donor element arranged on the end shield and a sensor which can be switched by the donor element, wherein the donor element is arranged to be pluggable on an inner wall of the end shield. According to one embodiment, the sensor with associated evaluation electronics is arranged on a printed circuit board which can be clipped into an opening in a circuit board fastened to the axial end of the stator.

DE 38 31 551 A1 discloses a printed circuit board with a metallic layer support body, on which a flat insulating layer and on this a layer with individual metallic conductor tracks for connection of electrical components is provided. In the circuit board at least one recess for receiving a component is impressed.

DE 197 20 106 A1 discloses a device for receiving electrical components, wherein at least one component is mounted on an at least partially movable or flexible carrier, which is a partially movable or flexible carrier of thin flexible polymer or of another flexible material or of a rigid Material with Flying Leeds or a rigid-flex rigid connection.

It is an object of the invention, a device for mounting and Fixation of the sensor device in the DC motor of the beginning specify type described, the relative relative reliability of the sensor positioned to a signal generator.

These The object is achieved by a device having the features of claim 1 solved.

It is a device for holding and positioning the sensor device proposed relative to a signal generator, which the sensor device free of play and in a defined and reproducible position positioned and fixed in the motor. This is necessary to get a reliable measurement result the sensor device, for example, with respect to the position of Rotor relative to the stator, to obtain. For the connection and the Positioning of the sensor device is provided that this is placed on a ribbon cable. The ribbon cable with the sensor device on it or the sensor device itself mounted on a carrier plate, which can be inserted in a pocket or groove, which is a solid spatial Assignment to the signal transmitter has. The pocket or groove is on the flange or the base plate is formed.

In a preferred embodiment has the carrier plate at least one squish bead, preferably two squish beads two opposite edges the carrier plate on to the backing plate into the pocket or groove. The carrier plate can pin for attachment having the sensor device. Advantageous is a strain relief provided, which is connected to the carrier plate is to connect the carrier plate with relieve the ribbon cable. In an expedient embodiment, the carrier plate is as a stamped and bent part of a sheet, in particular a steel sheet produced. The carrier plate has the surprising Advantage that they serve in addition to their holding function as a conclusion for the sensor device can.

In a preferred embodiment The invention provides an inductive sensor device which an excitation coil and a measuring coil comprises which is positioned in a defined and reproducible position in the engine are to generate a signal upon rotation of the shaft, referred to is on the rotational position, speed and / or torque of the rotor assembly. For this purpose, in one embodiment of the invention the shaft has two tooth tracks running around the circumference of the shaft, e.g. imprinted, which are designed according to the vernier principle. The exciter coil and the measuring coil are arranged relative to the shaft so that they are in connection with these Tooth marks a high-resolution Output signal can generate, the a measure of the rotational position and speed of the motor shaft is. In particular, the sensor device generates a position signal with high resolution, a position signal with low resolution and a speed signal used to generate high precision commutation signals serve.

The The invention also provides a DC motor of the type described above At front, where the pocket or groove on the flange or the base plate is formed and the carrier plate pressed into the pocket or groove is.

The The invention is described below with reference to preferred embodiments closer to the drawings explained. In the figures show:

1 a schematic sectional view through a DC motor according to the invention;

2 a schematic sectional view of the arrangement of flange and rotor assembly to illustrate essential features of the DC motor according to the invention;

3 a perspective view of the stator body;

4 a similar view as 3 , Where in addition, a part of the housing surrounding the stator body is shown;

5 a perspective view of a support plate for positioning and fixing the sensor device;

6 a perspective enlarged view of a portion of the flange with the support plate and the sensor device, wherein for clarity parts of the flange are broken away;

7 a similar view as 6 from a different angle;

8th a top perspective view of a housing cover of the DC motor;

9 a perspective bottom view of the housing cover;

10a a partial perspective view of a cylindrical motor housing;

10b a sectional partial view of the motor housing the 10a with inserted end cap;

10c a sectioned enlarged view of the cutout X from 10b ;

11a to 11c similar views as in the 10a to 10c a further embodiment of the motor housing and end cap;

12 a schematic representation of a device for forming an axial positioning aid on a shaft of a DC motor;

13 a sectional view through part of the device of 12 ;

14 a schematic perspective view of a shaft are formed on the positioning projections by plastic deformation; and

15 a schematic perspective view of a shaft on which a ball bearing is mounted.

1 shows a schematic sectional view through a brushless DC motor according to the invention. The in 1 shown DC motor comprises a flange or a base plate 10 for fixing the engine, for example in a motor vehicle. The flange 10 is non-rotatable with a stator 12 connected, the one constructed of sheet metal stator body 14 and phase windings 16 includes. A rotor 18 is non-rotatable with a shaft 20 connected and rotates relative to the flange 10 and the stator 12 , The rotor 18 includes a rotor magnet 22 and an iron yoke 24 , The rotor 18 and the wave 20 are about two rolling bearings 26 . 28 in particular ball bearings, in the flange 10 stored on one side.

A cylindrical motor housing 30 extends from the flange 10 to a housing cover 32 and surrounds the stator body 14 , The housing cover 32 has a first connector 34 for powering the motor and a second connector 36 for control and signal lines. In the first connector 34 is a pin 38 hinted that with one of the windings 40 is connected. On its inside, the housing cover 32 a relay holder 42 on, in which a switching relay 44 is held.

Between the two camps 26 . 28 is in the flange 10 a sensor device 46 provided, that of a signaling device 48 is assigned on the shaft. In the embodiment shown, the signal generator 48 formed by two impressed on the shaft tracks with vernier pitch, which a position sensor 46 opposite. The sensor device 46 is via a ribbon cable 50 with terminals (not shown) in the second socket 36 of the housing cover 32 connected. The ribbon cable 50 is a so-called flex cable with, for example, nine lines. It is through a diagonal bore 52 between the two camps 26 . 28 led out of the flange and runs on the outside of the stator 14 between the stator body and the wall of the motor housing 30 , The hole 52 is guided so that it is ensured that the bearing seats in the flange 10 not be weakened.

As in 1 shown is the motor shaft 20 with the rotor 18 on it over the two camps 26 . 28 one-sided in the flange 10 clamped so that the rotor 18 is easily accessible. However, this leads to the problems of deflection of the free end described above 54 the wave 20 due to a summation of the tolerances of the radial clearance of the bearings and the bearing seats. In addition, a lateral stress of the shaft and the flange can reinforce the radial deflection. Radial deflection of the shaft 20 at her free end 54 can become so large that a reliable detection of the rotational position is no longer guaranteed at this point. It is therefore proposed, the sensor device 46 in the area of the flange 10 between the two camps 26 . 28 accommodate where the radial deflection of the shaft 20 is lowest. Not only is the mechanical bearing of the sensor between the bearings 26 . 28 most stable, in this area, the temperature fluctuations are the lowest for the reasons explained.

2 shows a schematic sectional view of the arrangement of the flange 10 and the rotor assembly 18 , which is largely an enlarged partial view of the 1 equivalent. The stator 12 and the housing cover 32 are omitted in this illustration. Like or corresponding parts are designated by the same reference numerals and will not be described again.

In the presentation of the 2 is in particular the bearing clearance of the bearings 26 . 28 to recognize that to a radial deflection of the shaft 20 can lead.

Furthermore, the ribbon cable 50 shown with further details. This ribbon cable 50 connects the sensor device 46 with connections in the housing cover 32 , It leads from the sensor device 46 through the oblique hole 52 between the flange 10 and the phase winding 16 of the stator (in 2 not shown) and extends along the outer circumference of the stator 12 (in 2 Not shown).

3 schematically shows a perspective view of a stator body, for example, the stator body 14 out 1 , The stator body 14 is composed of several stacked, pressed stator laminations, which are in 3 not shown in detail. Alternatively, the stator body can also be made of a single component.

In the prior art is the round motor housing 30 , see also 4 completely filled by the stator with the phase windings, the outside of the stator body 14 on the inner diameter of the housing 30 is present or only a small radial distance to this has. To guide the ribbon cable between the outside of the stator 14 and the inner diameter of the housing 30 is the stator body as in 3 shown designed. The stator body 14 is preferably constructed of a plurality of laminated stator laminations and has basically a cylindrical diameter 60 , The cylindrical diameter 60 serves for the centric guidance of the stator body 14 in the cylindrical housing 30 , as in 4 shown. The outer circumference of the stator body 14 also has flats 62 and welding grooves 64 for connection to the housing 30 on. In 3 are also pin connections 66 indicated, also the attachment of the stator body 14 serve inside the motor housing.

As in 4 is shown between each flattening 62 and the inner diameter of the motor housing 30 a recess or a space for the passage of the ribbon cable 50 educated. The flattenings 62 , Welding grooves 64 and tenon joints 66 are on the circumference of the stator body 14 equally distributed. In order to influence the magnetic flux as little as possible, the flats are preferably always arranged opposite to a pole pair of the stator, because here the flux density is minimal. In practice, it is characterized by an even distribution of flattening 62 and welding grooves 64 on the circumference of the stator body 14 possible to realize a twisted punching package of stator laminations by the flats 62 and welding grooves 64 be arranged with the same angular pitch as the twist angle in the packaging. From a twisted stamped package results in the prior art known per se advantages of uniform distribution of the rolling direction of the stator and thus a uniform thickness and flux distribution in the stator.

With the described training of the stator body 14 becomes an easy-to-implement guide for a ribbon cable between stator body 14 and housing 30 created. The on the circumference of the stator body 14 distributed several flattenings 62 In addition to ensuring a uniform flow distribution have the advantage that when installing the stator 12 in the flange 10 and the motor housing 30 its angular position relative to the bore 50 in the flange 10 is relatively uncritical because the ribbon cable 50 at each of the flattenings 62 can be passed on the stator.

Of course, a corresponding, for the implementation of the ribbon cable 50 suitable recess on the inside of the motor housing 30 be provided.

A sensor holder and its fixation on the motor flange 10 is in the 5 to 7 shown schematically. 5 shows a carrier plate 70 for mounting the sensor of the sensor device 46 on one end of the ribbon cable 50 is applied. The carrier plate 70 has cones 72 for receiving the sensor, for example, in the carrier plate 70 can be pressed. Furthermore, the carrier plate comprises 70 Crimping on both sides 74 for mounting and holding the carrier plate 70 in the engine flange 10 , as explained in more detail below.

6 and 7 show the carrier plate 70 with the sensor mounted on it 46 in its installed position in the flange 10 with parts of the flange broken away for clarity. As in the 6 and 7 shown is the sensor 46 on one end of the ribbon cable 50 arranged and soldered with this example. The end of the ribbon cable 50 with the sensor 46 it is about the cones 72 on the carrier plate 70 attached. The carrier plate 72 gets into a pocket or guide groove 76 . 76 ' pushed in to the flange 10 out is forming. Here is the carrier plate 70 with their side edges, at which squeezing 74 are trained in the bag 76 . 76 ' firmly pressed. When inserting the carrier plate 70 in the pocket 76 . 76 ' the squeezing beads deform 74 and thus provide a tight fit of the carrier plate 70 in the flange 10 for sure. The ribbon cable 50 gets through the hole 52 from the flange 10 led out.

The carrier plate 70 For example, can be made of a steel sheet, wherein the pins 72 and the bruises 74 be formed by pressing the sheet. The carrier plate 70 is preferably produced as a stamped and bent part. The ribbon cable 50 with the sensor 46 it will be with the cones 72 for example, connected by riveting. For strain relief, it can with an additional disc on the support plate 70 be secured.

With the described solution for positioning and mounting the sensor device 46 a very simple, accurate and play-free, permanent attachment of a sensor for commutation of brushless DC motors is achieved. As a result, the previously conventional in the art screwed printed circuit boards for receiving sensors are replaced.

8th and 9 show a perspective top view and a bottom perspective view of the housing cover 32 , which the motor housing 30 tightly closes and provides the necessary connections for power supply and signal lines. The housing cover is as an end cap 32 formed and has a male / female section 80 for the power supply lines and a male / female section 82 for signal lines. These are in one piece with a disc-shaped lid 84 produced. In the male / female section 80 are three pins 86 provided for connecting the supply lines to the phase windings. The male / female section 82 in turn has a number of connection pins 88 in the embodiment shown 16 Connection pins, for signal cables. While 8th the outside or top of the housing cover 32 shows, which is in the mounted state outside the engine is in 9 the inside or underside of the Geshäusedeckels 32 shown, wherein the same components are denoted by the same reference numerals.

On the inside of the housing cover 32 are the pins 86 for the phase windings as well as drilling 90 for receiving signal lines connecting the connection pins 88 of the male / female section 82 correspond. On the inside of the housing cover 32 is also a holder 92 for an electromechanical component, in particular a power switching device, such as a relay provided. This bracket 92 is also integral with the disc-shaped lid 84 and the male / female sections 80 . 82 of the housing cover 32 educated. In 3 is also an impressed ground contact 94 , which is designed as a stamped and bent part, shown.

In order to minimize the expense for seals between the electric motor and the housing cover of the electric motor and in the area of the terminals, a housing cover is proposed in which all electrical connections, for phase windings and signal lines, are made via connectors and the associated male / female sections 80 . 82 are integrally formed with the housing cover. Thereby, the seal can be reduced to a seal on the circumference of the housing cover and thus the reliability of the seal can be improved. Integrally formed with the housing cover is also the holder 92 for a power switching device, in particular a relay 96 , As a result, the effort for assembly is further reduced. In addition, further functions, such as the mounting and fixing of other engine components, can be integrated into the housing cover.

In the embodiment shown, the housing cover is as an end cap 32 executed, which is preferably produced by injection molding as an integral component.

10a to 10c and 11a to 11c schematically show a first and a second embodiment for connecting the housing cover 32 with the motor housing 30 , in which 10c an enlarged partial view of the 10b and 11c an enlarged partial view of the 11b , in each case in the region of the circle marked with X, is.

For sealing and simultaneous bonding of motor housing 30 and housing cover 32 is between a surface 100 the motor housing and an adjacent surface 102 the housing cover a cavity 104 educated. In the embodiment shown, the cavity 104 through an annular recess or groove on the outer circumference of the housing cover 32 formed in the motor housing 30 is used. A similar annular recess could alternatively or additionally on the inner circumference of the housing 30 be formed. In the housing wall is at least one opening 106 introduced, which is designed for example as a counterbore. For connection and sealing of the two parts 30 . 32 will be over the opening 106 a plastic with sealing and adhesive function in the annular cavity 104 injected. The cavity 104 forms a channel and the material injected in the liquid state flows along this annular channel until it is completely filled. As a mate For example, thermoplastic elastomers or PU-based two-component adhesives can be used. After solidification of the material is the connection of housing 30 and housing cover 32 mechanically loadable and simultaneously sealed along the joint.

The best connection is achieved on adjoining surfaces, on which a shear load acts. However, the method described can be also on sealing surfaces in different levels and to connect more than two housing parts apply. about a gate point and a suitable further channel can for this purpose the compound and sealant further sealing surfaces (not shown in the figures).

When choosing the material for making the connection and sealing the two components must be noted that they can be made of different materials, such as metal or plastic, and the material with all the materials must make a tight connection. In practice, moreover, in addition to the injection port 106 at least one vent opening are provided for the sealing material.

The described device for connecting and sealing two components can be everywhere are used where a mechanical connection of two surfaces below simultaneous sealing is necessary. In particular, it is used on the described electric motor for connecting the housing cover with the motor housing or the motor housing with the flange. When using the engine according to the invention in a motor vehicle, e.g. as an auxiliary engine for steering or driving the cooling water pump, This ensures that the Engine against environmental influences, like splashing water and other contaminants, is protected.

12 and 13 show schematically in perspective or sectional view a device for producing an axial securing to a shaft and 14 shows the machined shaft.

12 schematically shows a wave 20 with a rotor 18 which is mounted on the shaft. In the wave 20 is an annular groove 110 educated, as well as in 14 shown. A support and guide block 112 serves to hold the shaft 20 and guiding a deformation tool 114 , eg a stamp. With the deformation tool 114 which is moved in the arrow direction shown becomes along an edge of the groove 110 Material from the shaft by spatially limited plastic deformation to a positive stop 116 (please refer 14 ).

This positive stop 116 serves as an axial stop for mounting components on the shaft. The stop is realized with minimal use of materials and effort for additional parts. This represents a significant improvement over the prior art. From the prior art, several types of positive definition of axial bearing positions are known. For example, a paragraph can be made on a rotary part, which prevents axial displacement. It is also known to lock a retaining ring in a groove. However, the known methods usually require at least the use of several components or a source material for the shaft, which has a larger diameter than the final diameter of the shaft. With the method described, positive stops for a component to be mounted on the shaft are formed on the shaft without requiring additional components or a shaft with a larger output diameter. The method also has the advantage that the stops can be formed even if components already mounted on the shaft in an earlier operation are present. These components can even be sensitive components, such as ball bearings or magnetic rings.

15 schematically shows the shaft 20 with the rotor 18 and the stops formed on the shaft 116 for axial positioning of a ball bearing 118 serve.

The in the foregoing description, claims and drawings Features can both individually and in any combination for the realization the invention in its various embodiments of importance be.

10

Base plate, flange

12

stator

14

stator

16

phase windings

18

rotor

20

wave

22

rotor magnet

24

Iron yoke

26 28

roller bearing

30

motor housing

32

Cover, end cap

34 36

socket

38

pin

40

windings

42

relay holder

44

switching Relays

46

sensor device

48

signaler

50

Flat channel

52

drilling

60

diameter

62

flats

64

welding grooves

66

tenon joints

70

support plate

72

spigot

74

Quetschsicken

76 76 '

Bag, groove

80 82

Male / female connector portion

84

cover

86

pin

88

connection pin

90

drilling

92

bracket

94

mass contact

100 102

area

104

cavity

106

opening

110

groove

112

mounting support and leadership block

114

Deformation tool stamp

116

attack

118

ball-bearing

Claims (9)

Device for holding and positioning a sensor device ( 46 ) relative to a signal generator in a DC motor, wherein the DC motor comprises a rotor assembly ( 18 ), a stator assembly ( 12 ), the sensor device ( 46 ) and a flange ( 10 ) or a base plate for mounting the DC motor, characterized by a) a carrier plate ( 70 ) made of sheet metal on which the sensor device ( 46 ) and which serves as a conclusion for the sensor device, and b) a receiving device ( 76 . 76 ' ) for receiving the carrier plate ( 70 ), c) the receiving device ( 76 . 76 ' ) comprises a groove or pocket attached to the flange ( 10 ) or the base plate is formed and which has a fixed spatial association with the signal generator, d) the sensor device ( 46 ) with a ribbon cable ( 50 ) connected to the carrier plate ( 70 ), and e) the carrier plate ( 70 ) with the sensor device ( 46 ) and the ribbon cable ( 50 ) is pressed into the groove or pocket. Device according to claim 1, characterized in that the carrier plate ( 70 ) at least one crimp bead ( 74 ) having. Apparatus according to claim 2, characterized in that the carrier plate ( 70 ) two squeezing beads ( 74 ) at two opposite edges of the carrier plate ( 70 ) having. Device according to one of the preceding claims, characterized in that the carrier plate ( 70 ) Pins ( 72 ) for mounting the sensor device ( 46 ) having. Device according to one of the preceding claims, characterized by one or more strain relief discs which are connected to the carrier plate ( 70 ) connected is. Device according to one of the preceding claims, characterized in that the carrier plate ( 70 ) is a stamped and bent part. Device according to one of the preceding claims, characterized in that the carrier plate ( 70 ) is made of a steel sheet. DC motor with a shaft ( 20 ), a rotor assembly ( 18 ), the at least one permanent magnet ( 22 ), which is centered on the shaft ( 20 ), a stator assembly ( 12 ), which has a stator body ( 14 ) and phase windings ( 16 ), a flange ( 10 ) or a base plate at a front end of the stator assembly ( 12 ) for mounting the DC motor, a sensor device ( 46 ) for detecting a magnitude that is related to the rotational position, rotational speed and / or torque of the rotor assembly ( 18 ) relative to the stator assembly ( 12 ), one of the rotor assembly ( 18 ) associated signal transmitter ( 48 ) connected to the sensor device ( 46 ) and with a device according to any one of the preceding claims DC motor according to claim 8, characterized in that the shaft ( 20 ) and the rotor assembly ( 18 ) over two bearings ( 26 . 28 ) on one side in the flange ( 10 ) or the base plate are mounted and the sensor device ( 46 ) between the two camps ( 26 . 28 ) is arranged.