DE102019125063A1 - Electric motor - Google Patents

Abstract

The invention relates to an electric motor with a stationary motor component (10, 12) and a rotatable motor component (14, 16) which is rotatably mounted by means of a slide bearing (12, 36, 38a, 38b) and is driven by an electromagnetic drive system (18, 30) , the electromagnetic drive system (18, 30) having a stator arrangement (18) with a stator core (20), at least one side of the stator core (20) being covered by a first insulator (22, 122) which seals the slide bearing (12, 36, 38a, 38b), and that a shaft seal (22a, 122a) is arranged on the first insulator (22, 122), through which one end of the shaft (14) is sealingly led out of the bearing receptacle (10a) .

Description

The invention relates to an electric motor according to the preamble of claim 1. In particular, the invention relates to an electric motor for driving a fan wheel, which is mounted by means of a fluid dynamic bearing system.

The DE 10 2011 113 029 A1 discloses a fan motor with a stationary motor component and a rotatable motor component which is rotatably mounted by means of roller bearings and is driven by an electromagnetic drive system. It is described there that the roller bearing can be replaced by a plain bearing, which reduces complexity and costs.

The EP 1 378 983 A2 discloses a fan motor with the features of the preamble of claim 1, in which a sliding bearing is used for the rotary bearing of the motor. The bearing area is sealed in order to prevent dirt from penetrating into the sliding bearing or bearing fluid from escaping from the bearing area.

The fan motors described consist of many individual parts and are complex to assemble, which is costly.

The object of the present invention is to provide an electric motor, in particular for driving a fan, which consists of a few and easy-to-assemble individual parts, as a result of which the production costs can be reduced.

According to the invention, this object is achieved by an electric motor with the features of claim 1.

Preferred embodiments of the invention and further advantageous features are specified in the subclaims.

The electric motor comprises a stationary motor component and a rotatable motor component which is rotatably mounted by means of a sliding bearing and is driven by an electromagnetic drive system, the electromagnetic drive system having a stator arrangement with a stator core.

According to the invention, at least one side of the stator core is covered by a first insulator, which at the same time forms a cover for the sliding bearing.

According to the invention, with the first insulator, a component is now proposed which fulfills several functions at the same time, on the one hand electrical insulation of the stator core and on the other hand a cover and seal for the sliding bearing.

In a preferred embodiment of the invention, the sliding bearing is arranged in a bearing seat of the stationary motor component and comprises a bearing bush which is arranged in the bearing seat and in which a shaft is rotatably mounted.

According to the invention, the bearing receptacle is covered and closed by the first insulator.

In particular, a shaft seal is arranged on the first insulator, through which one end of the shaft is led out of the bearing receptacle in a sealed manner.

The shaft seal can be formed in one piece with the first insulator and consist of the same material as the first insulator, or the shaft seal can be molded onto or attached to the first insulator and consist of a different material from the first insulator.

For example, the first insulator can consist of plastic, the shaft seal being designed as a plastic lip which rests on the shaft.

The first insulator is preferably made of a plastic that is elastic, temperature-resistant, oil-resistant and slidable.

The shaft seal can consist of a classic shaft seal, which is injection-molded onto or attached to the first insulator as an additional part, or of a sealing lip that is made, for example, of an elastomer or another elastic and slidable material and is molded onto the first insulator.

The plain bearing is preferably lubricated with a bearing fluid and comprises an axial thrust bearing and at least one fluid dynamic radial bearing. If the operating temperature of the bearing increases, the lubricating oil can evaporate over time, which is a crucial failure criterion for a plain bearing.

The underside of the stator core is covered by a second insulator. The first and the second insulator can be two separate parts or, according to the invention, they can also consist of a single component, for example in the form of an overmolding of the stator core with plastic.

The stator core is electrically isolated by the first and second insulator and at the same time a Formed bobbin or winding carrier on which the stator windings are applied.

According to a further preferred embodiment of the invention, the first insulator is fastened to the stationary motor component with the aid of the stator arrangement, while the first insulator rests against the open top of the bearing receptacle and covers it.

The bearing receptacle is tightly closed at the bottom and is covered and sealed at the top by the first insulator. The closed and sealed bearing receptacle is at least partially filled with a bearing fluid for lubricating the plain bearings.

The electric motor according to the invention is preferably suitable for driving a fan, in particular also for high operating temperatures. High temperatures favor evaporation of the bearing fluid in the area of the plain bearing, the leakage of bearing fluid from the bearing area being largely prevented by the sealing of the plain bearing and the existing shaft seal on the rotating shaft.

The first insulator therefore has several functions, namely to isolate the stator core from the stator windings, as a coil body and winding carrier, to accommodate the electrical connections for connecting the stator windings to a circuit board, to mechanically fasten the stator windings to the bearing seat and to seal the rotating shaft of the Plain bearing against the ingress of dirt and the escape of bearing fluid from the bearing seat.

• 1 zeigt einen Schnitt durch einen Lüfter mit einem erfindungsgemäßen Elektromotor.
• 2 zeigt eine vergrößerte Teilansicht von 1.
• 3 zeigt eine abgewandelte Ausführungsform einer Wellendichtung.

Preferred exemplary embodiments of the invention are described in more detail below with reference to the drawings. This results in further features and advantages of the invention.

• 1 shows a section through a fan with an electric motor according to the invention.
• 2 FIG. 11 shows an enlarged partial view of FIG 1 .
• 3 shows a modified embodiment of a shaft seal.

In 1 is a section through a fan with an electric motor according to the invention. The fan includes a fan housing 10 , which forms the fixed motor flange at the same time. The fan housing is preferably made of plastic. On this fan housing and motor flange 10 is an approximately sleeve-shaped motor mount 10a arranged, preferably formed in one piece, which is closed at the bottom and in which a bearing bush 12th a plain bearing system is arranged.

The inventory 10a can have axially extending ribs on its inner circumferential surface 42 have on which the outer peripheral surface of the bearing bush 12th rests and is held.

The bearing bush 12th includes a central bearing bore in which a shaft 14th is rotatably mounted. For rotating the shaft 14th a plain bearing system is used, which preferably consists of an axial thrust bearing 36 consists of that at the bottom of the bearing mount 10a is arranged, and preferably two fluid dynamic radial bearings 38a , 38b which are arranged at an axial distance from one another. The bearing surfaces of the two radial bearings 38a , 38b may include bearing groove structures, which are preferably arranged on the surface of the bearing bush 12 and which when the shaft rotates 14th in the bearing bush 12th generate a hydrodynamic pressure and increase the bearing rigidity of the plain bearing.

The bearing bush 12th consists preferably of a metallic sintered material which is impregnated with a bearing fluid. Furthermore, the bearing receptacle is preferably at least partially filled with the bearing fluid, in particular the area of the thrust bearing 36 as well as the spaces between the ribs 42 between the inner circumference of the bearing seat 10a and the outer circumference of the bearing bush 12th .

The free one, from the bearing bush 12th outstanding end of the shaft 14th is with a rotor 16 connected, which in the present case is designed as a fan wheel or impeller.

The wave 14th is preferably made of metal, while the rotor 16 made of plastic. The rotor 16 can preferably be designed as an injection molded part, the shaft 14th is injected as an insert into this injection molded part. Alternatively, the rotor 16 and the wave 14th be connected to one another by means of a press connection and / or adhesive.

The electromagnetic drive system for the rotor 16 includes a stator assembly 18th , which is arranged on the stationary motor component, and a permanent magnet 30th on an inner peripheral surface of the rotor 16 at a small radial distance from the stator 18th is arranged. The magnet 30th can be used to optimize the magnetic circuit on a magnetic return ring 32 be arranged. The return ring 32 can also be used as an insert from the plastic material of the rotor 16 be encapsulated. The permanent magnet 30th is then for example by a press connection and / or an adhesive connection to the return ring 32 connected.

The stator assembly 18th includes a stator core 20th stacked from individual metal sheets. For electrical insulation of the stator core 20th are on the top and on the bottom of the stator core 20th a first insulator each 22nd and a second isolator 24 arranged, which are preferably made of a plastic material. The first isolator 22nd and the second isolator 24 can consist of separate components, but they can also preferably be designed as a one-piece component, in which case the stator core 20th is encapsulated as a whole with a plastic material.

The first isolator 22nd and the second isolator 24 form in the area of the stator core 20th each has a cross-sectionally approximately U-shaped receptacle, which acts as a winding body for receiving the stator windings 26th serves.

The first isolator 22nd is designed as a disc-shaped, profiled body, and comprises on its outer edge the winding body, which is approximately U-shaped in cross section, and in the center an approximately flat surface offset therefrom, which is used to cover and seal the bearing receptacle 10a serves.

The first isolator 22nd lies on the upper opening of the bearing mount 10a and can with the edge of the bearing mount 10a be connected, for example by plastic welding, since both components are preferably made of plastic. Simultaneously through the connection between the first insulator 22nd and stock taking 10a the entire stator assembly 18th , consisting of the stator core 20th , the two isolators 22nd , 24 and the stator windings 26th on the stationary engine component 10 attached.

The first isolator 22nd has a central opening through which the free end of the shaft 14th is carried out. 2 shows that for sealing against the shaft 14th on the first isolator 22nd a shaft seal 22a is provided, which is designed, for example, as an annular sealing lip that is attached to the shaft 14th is applied. The shaft seal 22a seals the bearing support 10a against the environment so that no dirt gets into the storage system or the bearing receptacle 10a penetrate and no bearing fluid from the bearing receptacle 10a can escape.

The shaft seal 22a is preferably to the first insulator 22nd integrally formed and can consist of the same material as the first insulator. The shaft seal 22a but can also be connected to the material of the first insulator 22nd be molded on or connected to this and consist of a different material or a separate component, for example an elastomeric sealing material or a shaft sealing ring or the like.

The first isolator 22nd can also have ribs 22b have, which in the axial direction in the bearing seat 10a are directed into it. Ribs 22b are preferably on the face of the bearing bush 12th on and prevent positively that the bearing bush 12th can move in the axial direction.

The second isolator 24 can with a circuit board 28 be connected, via which the electrical connections for the stator windings 26th are led. Here electrical connections for the stator windings 26th into the second isolator 24 be integrated, the second insulator 24 for example via plug connections electrically with connections on the circuit board 28 connected is.

For the axial thrust bearing 36 a magnetic preload is preferably provided, which is caused by an axial offset of the magnetic center of the rotor magnet 30th with respect to the magnetic center of the stator core 20th the stator assembly 18th is achieved. Here lies the magnetic center of the magnet 30th further away from the plane of the thrust bearing than the magnetic center of the stator core 20th so that there is a magnetic force downwards in the direction of the thrust bearing 36 results in the rotating engine component and in particular the end of the shaft 14th against the thrust bearing 36 presses.

The rotor component 16 can at least partially from the fan housing 10 surrounded and by one with the fan housing 10 connected housing cover 34 be at least partially covered.

By means of a hall sensor 40 , for example on the circuit board 28 axially below the magnet 30th is arranged, the current position of the rotor 16 to control the electronic commutation.

In 1 and 2 is the shaft seal 22a preferably designed as an annular sealing lip on the circumference of the shaft 14th preferably rests and consists of an elastomeric material.

3 shows a modified embodiment of a shaft seal 122a as an axially extending sealing gap or capillary sealing gap 44 is trained. Here, the first insulator 122 in the area of the shaft 14th a shaft seal 122a in the form of an axially extending sleeve through which the shaft 14th is carried out. The shaft seal 122a in this case touches the shaft 14th preferably not, but a narrow sealing gap remains 44 . Preferably is in addition to the capillary seal gap 44 a dynamic pump seal 122c in the first isolator 122 attached, the one inwards towards the bearing bush 12th Directed dynamic pumping action is generated, thereby reducing the outflow of the bearing oil.

List of reference symbols

10

Fan housing

10a

Stock taking

12th

Bearing bush

14th

wave

16

rotor

18th

Stator assembly

20th

Stator core

22nd

first isolator

22a

Shaft seal

22b

rib

24

second isolator

26th

Stator winding

28

Circuit board

30th

magnet

32

Return ring

34

Housing cover

36

Thrust bearing

38a, b

fluid dynamic radial bearing

40

Hall sensor

42

Ribs

44

gap

122

first isolator

122a

Shaft seal

122b

rib

122c

dynamic pump seal

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102011113029 A1 [0002]
• EP 1378983 A2 [0003]

Claims (14)

Electric motor with a stationary motor component (10, 12) and a rotatable motor component (14, 16) which is rotatably mounted by means of a slide bearing (12, 36, 38a, 38b) and is driven by an electromagnetic drive system (18, 30), the electromagnetic Drive system (18, 30) has a stator arrangement (18) with a stator core (20), characterized in that at least one side of the stator core (20) is covered by a first insulator (22, 122) which forms a seal for the sliding bearing ( 12, 36, 38a, 38b), and that a shaft seal (22a, 122a) is arranged on the first insulator (22, 122), through which one end of a shaft (14) is sealingly led out of a bearing receptacle (10a). Electric motor after Claim 1 , characterized in that the sliding bearing (12, 36, 38a, 38b) is arranged in the bearing receptacle (10a) of the stationary motor component (10) and comprises a bearing bush (12) arranged in the bearing receptacle (10a) in which the shaft ( 14) is rotatably mounted. Electric motor according to one of the Claims 1 or 2 , characterized in that the shaft seal (22a, 122a) is formed in one piece with the first insulator (22, 122) and consists of the same material as the first insulator (22, 122). Electric motor according to one of the Claims 1 or 2 , characterized in that the shaft seal (22a, 122a) is molded onto or attached to the first insulator (22, 122) and consists of a different material than the first insulator (22, 122). Electric motor according to one of the Claims 1 to 4th , characterized in that a capillary sealing gap (44) is arranged between the first insulator (22, 122) and the upper end of the shaft (14). Electric motor according to one of the Claims 1 to 5 , characterized in that a dynamic pumping seal (122c) is arranged between the first isolator (22, 122) and the upper end of the shaft (14), which generates a directed dynamic pumping action, Electric motor according to one of the Claims 1 to 6th , characterized in that the sliding bearing comprises an axial thrust bearing (36) and at least one fluid dynamic radial bearing (38a, 38b) and is lubricated with a bearing fluid. Electric motor according to one of the Claims 1 to 7th , characterized in that another side of the stator core (20) is covered by a second insulator (24). Electric motor according to one of the Claims 1 to 8th , characterized in that the first and second insulators (22, 122, 24) form a bobbin on which the stator windings (26) are applied. Electric motor according to one of the Claims 1 to 9 , characterized in that the first insulator (22, 122) is attached to the stationary motor component (10) by means of the stator arrangement (18). Electric motor according to one of the Claims 1 to 9 , characterized in that the stator arrangement (18) is fastened to the stationary motor component (10) by means of the first insulator (22, 122). Electric motor according to one of the Claims 1 to 11 , characterized in that the bearing bush (12) is held axially in the stationary motor component (10, 10a) by means of a rib (22b, 122b) of the first insulator (22, 122). Fan with an electric motor according to one of the Claims 1 to 12th . Laser scanner with an electric motor according to one of the Claims 1 to 12th .

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