DE102021118288A1 - Method for fastening or attaching a motor vehicle drive unit in or on an associated housing - Google Patents

Abstract

The invention relates to a method for attaching a motor vehicle drive unit (1) in or on an associated housing (2), in particular for fastening a door drive (1) in a drive housing (2), after which the housing (2) is produced and equipped with at least one Bore (5) for defining a bearing point for a preferably rotating drive component (7, 8, 9, 10, 11) is equipped. According to the invention, the bore (5) is produced during the manufacture of the housing with a cross section (Q1) below a usage dimension and is then reworked to the usage dimension (Q2).

Description

The invention relates to a method for attaching or fastening a motor vehicle drive unit in or on an associated housing, in particular for fastening a door drive in a drive housing, after which the housing is produced and equipped with at least one bore to define a bearing point for a preferably rotating drive component.

Depending on the application, motor vehicle drive units and in particular door drives must provide more or less large torques in order to be able to move the relevant motor vehicle door and in particular its door leaf. The motor vehicle door can generally be any door, flap or the like located in or on a motor vehicle. In particular, these include motor vehicle side doors, motor vehicle tailgates, but also motor vehicle front hoods, motor vehicle sliding doors, motor vehicle tank flaps, motor vehicle loading flaps, etc., to name just a few by way of example. That is, the term motor vehicle door and accordingly also the motor vehicle drive unit required to move it are to be interpreted broadly in each case.

In addition to the requirement to make large torques available with the help of such motor vehicle drive units, questions of acoustics and haptics play an important and even growing role in such motor vehicle drive units. In fact, such motor vehicle drive units are acted upon in so-called servo mode in such a way that the movement of the motor vehicle door generated by a user's hand, for example, is supported by the drive or the motor vehicle drive unit. In such a case, the user expects that any friction within the drive unit is as small as possible. In fact, at this point and because of the required torques, a multi-stage gear is typically used. In addition, a user assumes, particularly in servo mode, that the friction in the drive unit remains largely constant over the adjustment angle of the motor vehicle door.

Any deviation from this, in particular cyclical changes in the transmission friction or high friction within the transmission, are perceived as disruptive. This not only applies to the haptics, but also taking into account the noise development associated with such friction. Any undesired vibrations of the motor vehicle door when it is acted on by a motor are just as disturbing.

In the generic prior art according to DE 43 19 705 A1 the goal is already being pursued of working with a device for fastening a drive unit to a supporting part of a motor vehicle body with low manufacturing and assembly costs. For this purpose, connection means made of a material with high dimensional stability are used at fastening positions of the object to be fastened. In addition, a spacer can be attached with one end to a respective connection means and with the other end to the supporting part of the motor vehicle body. This is intended to avoid play in particular.

With another drive unit according to the DE 10 2018 127 315 A1 The procedure is such that each friction element that comes into engagement should minimize any play that may occur. This solves the objective of improving the radial alignment and tolerance for telescopic tubes in an extension mechanism.

In the DE 10 2019 121 640 A1 The procedure is such that the electrical energy required to act on a drive motor undergoes an adjustment, for example in order to suppress vibrations of an associated motor vehicle door. The teaching after that is similar DE 20 2015 105 598 U1 in which a generally driven member is displaced between first and second positions by a motor.

The state of the art consequently employs various methods and procedures in order to control motor vehicle door vibrations or any backlash. However, the procedures implemented and used at this point are relatively expensive if you use the specific connection means according to the generic prior art in accordance with the DE 43 10 705 A1 on the one hand or the friction elements in the DE 10 2018 127 315 A1 on the other hand considered.

Accordingly, the present invention is based on the technical problem of further developing such a method for fastening a motor vehicle drive unit in or on an associated housing in such a way that the design and technological effort is reduced compared to the prior art.

To solve this technical problem, the invention proposes in a generic method that the at least one hole in the housing to define the bearing point for a rotating drive component is produced during the manufacture of the housing with a cross-section below a usable dimension and is then reworked to the usable dimension.

The invention is based on the knowledge that the at least one bore for defining the bearing point for the regularly rotating drive component, for example a gear wheel of a transmission, cannot generally be defined in the housing with such precision and position during manufacture of the housing that this avoids bearing play. Rather, the invention has recognized that in particular the center distances of the individual rotating drive components, for example the center distances of the gears of a transmission connected downstream of an electric motor, are of central importance for the haptic and acoustic quality of the implemented drive or drive unit. So if the center distances of the individual gear stages in the example can be maintained exactly and specified during production, the gear backlash can be reduced to a minimum.

In order nevertheless to be able to manufacture the housing or drive housing inexpensively, the invention consequently proposes that the bore in question for defining the bearing point is produced with the cross section below the usage dimension during the manufacture of the housing. The usage dimension represents the cross-section of the bore, which is required so that, for example, a pin of the rotating drive component is held in the bore without play and can rotate. According to the invention, this usage dimension is only realized and implemented afterwards, namely in that the bore produced with the cross section below the usage dimension is then reworked to the usage dimension after the production of the housing or drive housing.

The invention is based on the knowledge that the production of the housing and thus also the one or more bores for the bearing points in question cannot usually be carried out with the required accuracy that is required to determine the center distances of the bearing points to be able to precisely adjust the individual rotating drive components in order to minimize play. Instead, injection molding processes are generally used at this point in the production of the housing, which do not deliver the required accuracy simply because of the temperature effects and material effects associated with them. On the other hand, such injection molding processes are particularly inexpensive, which is of particular importance in view of the large number of such motor vehicle drive units and is expressly retained according to the invention. Nevertheless, the gear backlash can be significantly reduced compared to previous procedures, because the bore is first produced with the cross section below the usage size and is only then reworked to the usage size after the housing has been manufactured. As a result, the center distances between the individual rotating drive components can be maintained and specified particularly precisely. This is where the main advantages can be seen.

As part of a variant with a particularly advantageous effect, the bore is regularly equipped with a bearing bush. The bearing bush can be integrated into a housing component during the manufacturing process of the housing. As a rule, the housing is equipped with at least two housing components. The housing components are, on the one hand, a housing base and, on the other hand, a housing cover. The lower housing part and the housing cover are combined with one another after the motor vehicle drive unit has been assembled. In this case, the housing can also be made media-tight overall from the two housing components, for example by means of an additionally inserted seal. As a result, any penetrating water, dust or dirt can be kept away from the motor vehicle drive unit located inside the housing.

The housing or the two housing components are usually produced by an injection molding process. It has proven useful if the housing components enclose the metallic bearing bush through the relevant injection molding process, in particular a plastic injection molding process. The metallic bearing bush can be made from a copper, zinc or tin alloy and can therefore also be subsequently machined particularly precisely and easily.

The two housing components can initially be temporarily connected to one another, with the hole in question only being reworked after this temporary connection. In this context, at least one bearing bush can be used as an alignment aid. The invention as a whole proceeds in such a way that the two housing components are connected to one another in their position of use, so that in this position of use the clamping post-processing of the respective bore and preferably of the bearing bush realized at this point is then carried out.

The bearing bushing used as an alignment aid for the temporary connection of the two housing components can be connected to her from the outset can be equipped to fit their intended use, so that post-processing is limited to the remaining bearing bushes. However, this is not mandatory. The decisive factor is the fact that the two housing components are temporarily connected to one another in their position of use, so that the one or more bearing bushes can be reworked by machining during this temporary connection. Following this, the temporary connection between the two housing components is canceled again in order to then place the motor vehicle drive unit inside the housing and carry out the assembly. Since the center distances of the respective rotating drive components, in particular the gears, have been set exactly according to the specifications in advance, a low-backlash and low-friction drive can then be expected during operation of the motor vehicle drive unit and any vibrations of the connected motor vehicle door are avoided due to the design. This is where the main advantages can be seen.

• 1 eine kraftfahrzeugtechnische Antriebseinheit zum Antrieb einer Kraftfahrzeug-Tür, hier einer Kraftfahrzeug-Heckklappe,
• 2 den Gegenstand nach der 1, reduziert auf die kraftfahrzeugtechnische Antriebseinheit und das Gehäuse in einer Aufsicht,
• 3 einen Schnitt durch das Gehäuse und
• 4 die Nachbearbeitung der einzelnen Lagerstellen.

The invention is explained in more detail below with reference to a drawing that merely represents an exemplary embodiment.

• 1 an automotive drive unit for driving a motor vehicle door, here a motor vehicle tailgate,
• 2 the item after the 1 , reduced to the automotive drive unit and the housing in a top view,
• 3 a cut through the case and
• 4 the post-processing of the individual storage locations.

In the 1 an automotive drive unit 1 is shown in or on an associated housing 2 . A motor vehicle door 3 is moved with the aid of the motor vehicle drive unit 1 and can be opened and closed in the present case. The motor vehicle door 3 is, in the exemplary embodiment and not restrictively, a tailgate in the rear area of a motor vehicle 4. However, it can just as well be a motor vehicle side door, although this is not shown.

In the present case, it is now particularly a matter of fastening the motor vehicle drive unit 1 in the associated housing 2 . The motor vehicle drive unit 1 is, within the scope of the illustration and not restrictively, a door drive 1, namely the door drive 1 for the tailgate 3. To fasten or attach the door drive 1 in the housing 2 or drive housing 2, the housing 2 is first produced and with at least one in particular in the 4 equipped to be recognized bore 5 to define a bearing point. That is to say, when the motor vehicle drive unit 1 is fastened or attached in the housing 2 , an associated pin 6 of a rotating drive component 7 , 8 , among other things, is accommodated in the bore 5 . The rotating drive component 7, 8 is as shown in FIG 2 on the one hand a drive gear 8 for acting on a toothed rack 9 as a further drive component 7, 8, 9 and on the other hand a pressure roller 7 for the toothed rack 9 in question. In addition, the electric motor with a in the 3 indicated worm 10 would come on its output shaft on the outer circumference side with the gear 8 and set it in rotation.

The rotations of the gear 8 now cause the rack 9 in the 2 indicated linear movements, which are transmitted to the motor vehicle door 3 via a joint 11 connected at the end, so that the motor vehicle door 3 can be pivoted in relation to the motor vehicle body or the motor vehicle 4, namely about an axis 12. It goes without saying at this point as well other designs of the individual drive components 7, 8, 9, 10, 11 of the drive unit or of the door drive 1 are conceivable and are covered by the invention.

The decisive factor is now the fact that in a method for attaching the motor vehicle drive unit or the door drive 1 in the housing 2, the procedure is such that the previously mentioned and in the 4 or drive housing 2 shown bore 5 to define the bearing point for the local rotating drive component 7, 8 or its associated pin 6 in the manufacture of the housing 2 is initially produced with a cross section Q ₁ below a usage dimension Q ₂ . D. h., So that the respective pin 6 of the rotating drive component 7, 8 in the example, ie the gear 8 as well as the pressure roller 7 for driving the rack 9 can be properly accommodated in the associated bore 5 in the housing 2, the question Bore 5 be equipped with the utility size, which to the cross-section Q ₂ in the representation after 4 corresponds.

However, this usage dimension or cross section Q ₂ is made available and realized according to the invention in such a way that the bore 5 is initially defined with the cross section Q ₁ below the usage dimension with the cross section Q ₂ during the manufacture of the housing 2 and then undergoes post-processing. As part of this post-processing, not only is the cross-section of the bore 5 of increased from the production dimension with the cross section Q ₁ to the usage dimension with the cross section Q ₂ . In principle, the position of the bore 5 can also be changed.

Here, the invention is based on the knowledge that the accuracy of a 4 indicated center distance A between the two bores 5 there is decisive for any play between the associated rotating drive components 7, 8 in the example, i.e. specifically for the play between the gear wheel 8 on the one hand and the pressure roller 7 on the other hand and consequently also for the respective play in comparison to the toothed rack 9 accommodated centrally between these two drive components 7, 8.

It can be seen that the housing 2 in the exemplary embodiment is composed of two housing components 2a, 2b. The housing component 2a is a housing bottom part 2a, while the other second housing component 2b is designed as a housing cover 2b that closes the housing bottom part 2a. Both housing components 2a, 2b are produced within the scope of the exemplary embodiment by injection molding and, in particular, plastic injection molding.

In detail, the procedure is such that first of all the bore 5 is equipped with a bearing bush 13 inserted therein. As already shown and explained above, the metal bearing bushing 13 has a cross section Q ₁ during the manufacturing process below the usage dimension with the cross section Q ₂ . In order to integrate the bearing bushing 13 into the manufacturing process of the housing 2, the bearing bushing 13 is enclosed by the injection molding process described, and in particular the plastic injection molding process. This can be done quickly and inexpensively. The bearing bushing 13 is a metal bearing bushing 13, which is advantageously made of copper, zinc and/or tin or corresponding alloys. Of course, other metals can also be used to realize the bearing bush 13 at this point.

In order to prepare the bearing bushing 13 inserted into the bore 5 after the manufacturing process and the associated cross section Q ₁ below the usage dimension with the cross section Q ₂ for the subsequent assembly of the pin 6 in question in the bore 5, the bearing bushing 13 in question is removed after the manufacturing process of the Housing 2 machined after. For this purpose, in the simplest case, the bearing bush 13 and consequently the bore 5 with one in the 3 indicated twist drill 14 are reworked by cutting. Of course, other post-processing steps are also conceivable. During this post-processing, a center associated with the cross-section Q ₁ during the manufacturing process can also be shifted in order to be able to set the axial distance A between the two bores 5 as precisely as possible. That's in the 4 indicated by dashed lines.

In order to be able to carry out the described post-processing of the bearing bush 5 in question, the lower housing part 2a and the upper housing part 2b are generally temporarily connected to one another. Only then is the hole 5 in question reworked. The temporary connection of the two housing components 2a, 2b can be carried out in such a way that at least one bearing bush 13 is used as an alignment aid. For example, it is conceivable that both housing components 2a, 2b in their in the 3 shown position of use to connect temporarily. The post-processing of the relevant bearing bore 5 can then be carried out from the outside by machining, for example with the twist drill 14, which for this purpose moves into the bearing bushing 13 located in the bearing bore 5 and processes it. In this way, the bearing bushing 5 in question is equipped with its usage dimension and the associated cross section Q ₂ after the manufacture of the housing 2 . Since the housing 2 is generally produced by plastic injection molding, any temperature effects and measurement inaccuracies naturally and in principle play no role in this post-processing. This is because post-processing is usually carried out at room temperature. Any shrinkage and/or expansion effects of the relevant housing components 2a, 2b do not occur.

As already explained, at least one bearing bushing 13 can be used as an alignment aid for the temporary connection of the two housing components 2a, 2b. As a rule, the bearing bushing 13 already has the cross section Q ₂ that is associated with and corresponds to the usage dimension as an alignment aid. However, this is not mandatory. It is conceivable here, for example, that a pin for alignment is inserted into the relevant bearing bushing 13 in the lower housing part 2a, which dips into a corresponding bore in the housing cover 2b, so that the two housing components 2a, 2b are thereby temporarily connected to one another, namely in their in the 3 illustrated position of use. In this position of use, the other second bearing bush 13 can then be reworked as described without any problems.

As soon as the bearing bushes 13 have undergone the desired post-processing, the pin for aligning the two housing components 2a, 2b is removed in the example described, the two housing components are opened and left then place the individual drive components 7, 8, 9, 10, 11 inside the housing 2 and attach them therein. The housing 2 is then closed. An additional seal (not expressly shown) can be provided between the lower housing part 2a and the cover or housing cover 2b in order to provide a media-tight closure of the housing 2 with the motor vehicle drive unit 1 located or attached therein.

Reference List

1

drive unit

1

door drive

2

Housing

2a

housing base

2 B

housing cover

3

motor vehicle door

4

motor vehicle

5

drilling

5

bearing bush

6

cones

7, 8, 9, 10, 11

drive component

8th

drive gear

8th

gear

9

rack

11

joint

12

axis

13

bearing bush

14

twist drill

A

center distance

Q1

cross-section

Q2

cross-section

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited 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 4319705 A1 [0005]
• DE 102018127315 A1 [0006, 0008]
• DE 102019121640 A1 [0007]
• DE 202015105598 U1 [0007]
• DE 4310705 A1 [0008]

Claims (10)

Method for attaching a motor vehicle drive unit (1) in or on an associated housing (2), in particular for fastening a door drive (1) in a drive housing (2), after which the housing (2) is produced and provided with at least one bore (5) for Definition of a bearing point for a preferably rotating drive component (7, 8, 9, 10, 11), characterized in that the bore (5) during the manufacture of the housing produces a cross-section (Q ₁ ) below a usage dimension and then up to the usage dimension (Q ₂ ) is reworked. procedure after claim 1 , characterized in that the bore (5) is equipped with a bearing bush (13). procedure after claim 2 , characterized in that the bearing bush (13) is integrated into a housing component (2a, 2b) during the manufacturing process of the housing (2). Procedure according to one of Claims 1 until 3 , characterized in that the housing (2) is equipped with at least two housing components (2a, 2b), namely a lower housing part (2a) and a housing cover (2b). Procedure according to one of claims 2 or 3 , characterized in that the housing component (2a, 2b) encloses the metallic bearing bush (13) by an injection molding process, in particular a plastic injection molding process. Procedure according to one of Claims 1 until 5 , characterized in that the bore (5) is reworked up to the usage dimension (Q ₂ ). Procedure according to one of Claims 4 until 6 , characterized in that the lower housing part (2a) and the housing cover (2b) are temporarily connected to one another and then the bore (5) is reworked. procedure after claim 7 , characterized in that at least one bearing bush (13) is used as an alignment aid for the temporary connection of the two housing components (2a, 2b). Procedure according to one of Claims 6 until 8th , characterized in that the two housing components (2a, 2b) are connected to one another in the position of use. procedure after claim 9 , characterized in that the bearing bush (13) for connecting the two housing components (2a, 2b) is equipped with its usage dimension (Q ₂ ).

Images