DE102019214307A1 - Electric motor-driven unit for a vehicle - Google Patents

Abstract

The invention relates to an electric motor-driven unit (1) for a vehicle, with at least one electric drive unit (2), the drive shaft (3) of which is mounted via at least one roller bearing (4), the outer ring (5) of which is secured against rotation on a housing part ( 7) of the unit (1) attached bearing bush (6) is added. In order to propose an improved unit in which the tendency to wear and the development of noise in the area of the roller bearing receptacle can be eliminated as cost-effectively as possible without significantly impairing manufacture and assembly, the invention proposes that the outer ring (5) also have a direct force-transmitting connection with the housing part ( 7).

Description

The invention relates to an electric motor-driven unit for a vehicle, in particular a vacuum pump, for example for supplying a pneumatic brake booster or a brake dust extraction system.

Modern vehicles have many units, which are driven by electric drive units or electric motors via rotating drive shafts, which are mounted in the housings of these units via roller bearings. However, the housing is often made of comparatively soft materials, in particular plastics, for weight, cost or manufacturing reasons. For reasons related to material technology, assembly or production, it is therefore often not possible to accommodate the roller bearing directly in the housing. To solve this problem, it is known to use separate bearing bushes in which the outer ring of the roller bearing is received, so that bearing forces are introduced into the housing via the bearing bush.

As an example of a relevant state of the art, an electric motor / pump assembly according to FIG WO 2016/026809 A2 referenced.

For manufacturing and assembly reasons, the outer ring of the rolling bearing often has to be accommodated in the bearing bush with a clearance fit. This type of storage has the disadvantage that the outer ring can rotate at the same time during operation. This can lead to wear of the components and considerable noise emissions.

The object is therefore to propose an improved unit in which the tendency to wear and the development of noise in the area of the roller bearing receptacle can be eliminated as cost-effectively as possible without significantly impairing manufacture and assembly.

The object is achieved according to the invention by the combination of features according to independent claim 1. Subclaims specify further embodiments and developments according to the invention.

The invention provides that, in addition to the connection to the bearing bush, the outer ring also has a direct force-transmitting connection to the housing part in some areas.

As a result, the outer ring is reliably locked in the bearing bush against unwanted rotation. Wear and noise emissions due to turning are eliminated. There is no need to choose a closer fit between the outer ring and the bearing bush, and manufacturability and assemblability are not adversely affected.

The invention further provides that the housing part has at least one clamping lug which is pressed against the outer ring in the assembled state. As a result, an additional contact point for direct force transmission between the outer ring and housing can be created, which is forcibly generated during assembly without further measures.

For simple and effective production and assembly, a preferred embodiment of the invention provides that the bearing bush has at least one tubular section for receiving the outer ring, which is arranged in a receiving cavity formed in the housing part and, according to a particularly preferred development, with its outer jacket surface therein radially is jammed.

According to two embodiments, one or more clamping lugs spaced apart from one another in the circumferential direction can be arranged in the receiving cavity in a space-saving and inexpensive to manufacture, which in the assembled state are pressed in the radial direction against the outer ring.

For further simplified production and assembly, a further development of the invention provides that such clamping lugs or clamping lugs are designed as centripetally pre-stretched projections which are designed in one piece with the housing part.

Another embodiment provides that at least one clamping lug is arranged pressed against the outer ring in the axial direction and, for this purpose, is preferably designed as an axially acting spring tab designed in one piece with the housing part.

In order to enable one or more clamping lugs to reach through to the outer ring in a particularly simple manner, a further development of the invention provides that the tubular section has at least one cutout for this purpose.

A stable and cost-effective structure can be implemented with a bearing bush made of metal, in particular sheet steel, which preferably has a clearance fit to the outer ring that is easy to assemble.

The invention can be used particularly effectively with a housing part made of plastic, in particular a fiber-reinforced plastic, for example a glass fiber-reinforced polyamide.

A particularly comprehensive utilization of the noise-reducing effect of the invention can can be achieved with a vacuum pump, which is connected to other acoustically effective components via sound-conducting pneumatic connections.

• 1 ein gattungsgemäßes elektromotorisch angetriebenes Aggregat am Beispiel einer Unterdruckpumpe.
• 2 einen Bereich einer erste Ausführungsform mit einer einzelnen radial wirkenden Klemmnase in einer räumlichen Explosionsdarstellung (a), im Querschnitt (b) sowie eine vergrößerte Ansicht der Klemmnase (c).
• 3 einen Bereich einer zweiten Ausführungsform mit mehreren radial wirkenden Klemmnasen in einer räumlichen Explosionsdarstellung (a) und im Querschnitt (b)
• 4 einen Bereich einer anderen Ausführungsform mit mehreren axial wirkenden Klemmnasen in einer räumlichen Explosionsdarstellung (a) und im Längsschnitt (b)

The invention is explained in detail below with reference to the description of the figures. Here show:

• 1 a generic unit driven by an electric motor using the example of a vacuum pump.
• 2 a region of a first embodiment with a single radially acting clamping nose in a three-dimensional exploded view (a), in cross section (b) and an enlarged view of the clamping nose (c).
• 3rd an area of a second embodiment with several radially acting clamping lugs in a three-dimensional exploded view (a) and in cross section (b)
• 4th an area of another embodiment with several axially acting clamping lugs in a three-dimensional exploded view (a) and in longitudinal section (b)

1 1 shows a generic unit 1 using the example of a vacuum pump to supply a pneumatic brake booster for the hydraulic brake system of a motor vehicle. One on the housing of the unit 1 attached electric drive unit 2 drives via a drive shaft 3rd drives two connecting rods via an eccentric drive, which transmit the movement to two oppositely arranged membrane units. In a housing part made of plastic 7th is a receiving cavity 10 molded. On a bearing bush made from sheet steel 6th is a tubular section 9 educated. The bearing bush 6th is secured against rotation on the housing part 7th fixed and engages with the tubular section 9 into the receiving cavity 10 on. In the tubular section 9 is the outer ring with a clearance fit 5 of a rolling bearing 4th added, which for storage he the drive shaft 3rd serves.

The materials described above are examples of a preferred application example; another choice of material remains permissible within the invention.

2 2 shows details of a first embodiment according to the invention. The receiving cavity 10 is approximately cup-shaped with a wall section 15th and a bottom section 16 educated. On the wall section 15th are several axially directed ribs 14th formed, which in the assembled state against the outer jacket surface 11 of the tubular section 9 are pressed and thus in the receiving cavity 10 jam. Next to the ribs 14th is within the receiving cavity 10 a clamping nose 8th provided which are significantly wider than the ribs 14th is stretched inwards. In the embodiment shown, the clamping nose is 8th than one on the housing part 7th integrally formed wedge-shaped projection, the tip of which is oriented in the centripetal direction.

The tubular section 9 has a cutout 12th , which in the assembled state with the clamping lug 8th is reached, so that the tip of the clamping nose 8th radially directly against the outer ring 5 is pressed and thereby a strip-like contact point 13th forms. Via the contact point 13th becomes a direct power transmission between the outer ring 5 and the housing part 7th it acts.

The axially directed, upper side of the clamping nose in the picture 8th is slightly from its base to the tip towards the bottom section 16 inclined designed to mount the rolling bearing 4th to simplify by acting as a kind of import ramp.

3rd In the 3rd another embodiment of the invention is shown. In contrast to the execution according to 2 are instead of one several projection-like clamping lugs 8th , 8 ', 8 "are provided, which are spaced from one another in the circumferential direction in the receiving cavity 10 are arranged. Compared to the individual projection described above, these are less pre-stretched in the radial direction, due to the plurality of contact points formed 13th , 13 ', 13 "will still have a sufficient clamping effect with the outer ring 5 reached. The top of the clamping lugs 8th , 8 ', 8 "is for the purpose of a simplified assembly of the rolling bearing 4th also designed beveled.

4th 4th shows another embodiment of the invention, which, in contrast to the variants described above, in the axial instead of the radial direction on the outer ring 5 acts. For this are in the bottom section 16 the receiving cavity 10 several clamping lugs distributed over the circumference 8th , 8 ', 8 ", which are designed as spring tabs. In the assembled state, these press axially onto the edge area of the outer ring 5 and tighten the entire rolling bearing 4th against one on the drive shaft 4th provided stop 17th .

List of reference symbols

1

Aggregate

2

Drive unit

3

drive shaft

4th

roller bearing

5

Outer ring

6th

Bearing bush

7th

Housing part

8th

Clamping nose

9

Tubular section

10

Receiving cavity

11

Outer surface

12th

Cutout

13th

Contact point

14th

rib

15th

Wall section

16

Floor section

17th

attack

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

• WO 2016/026809 A2 [0003]

Claims (15)

Electric motor-driven unit (1) for a vehicle, with at least one electric drive unit (2), the drive shaft (3) of which is mounted via at least one roller bearing (4), the outer ring (5) of which is secured against rotation on a housing part (7) of the unit (1) attached bearing bushing (6) is added, characterized in that the outer ring (5) also has a direct force-transmitting connection to the housing part (7) in some areas. Unit (1) after Claim 1 characterized in that the housing part (7) has at least one clamping lug (8) which is pressed against the outer ring (5). Unit (1) after Claim 2 characterized in that the clamping lug (8) is pressed in the radial direction against the outer ring (5). Unit (1) after Claim 2 characterized in that the clamping lug (8) is pressed in the axial direction against the outer ring (5). Unit (1) according to at least one of the preceding claims, characterized in that the bearing bush (6) has at least one tubular section (9) for receiving the outer ring (5), the section (9) in a receiving cavity formed in the housing part (7) (10) is arranged. Unit (1) after Claim 5 characterized in that the tubular section (9) is radially clamped with an outer jacket surface (11) in the receiving cavity (10). Unit (1) according to at least one of the Claims 5 or 6th characterized in that the tubular section (9) has at least one cutout (12) for the clamping nose (8) to reach through. Unit (1) according to at least one of the Claims 5 to 7th characterized in that at least one clamping lug (8) is arranged in the receiving cavity (10). Unit (1) after Claim 8 characterized in that several clamping lugs (8, 8 ', 8 ") are arranged in the receiving cavity (10) spaced apart from one another in the circumferential direction. Unit (1) according to at least one of the preceding claims, characterized in that at least one clamping lug (8) is designed as a projection which is centripetally extended in relation to the outer ring (5) and is designed in one piece with the housing part (7). Unit (1) according to at least one of the preceding claims, characterized in that at least one clamping lug (8) is designed as a spring tab which acts axially in relation to the outer ring (5) and is designed in one piece with the housing part (7). Unit (1) according to at least one of the preceding claims, characterized in that the bearing bush (6) is made of metal, in particular sheet steel. Unit (1) according to at least one of the preceding claims, characterized in that the housing part (7) is made of plastic, in particular a fiber-reinforced plastic, in particular a glass fiber-reinforced polyamide. Unit (1) according to at least one of the preceding claims, characterized in that the outer ring (5) is received with a clearance fit in the bearing bush (6). Unit (1) according to at least one of the preceding claims, characterized in that the unit (1) is a vacuum pump.

Images