DE102018210158A1 - Unit consisting of an electrical machine and a support element - Google Patents

Abstract

A structural unit (10) comprising an electrical machine (20) and a support element (30) is described, the support element (30) having a plurality of fastening openings (34) with an internally threaded section (34a) and the electrical machine (20) a ring-shaped one Stator (22) and a rotor (24) rotatably mounted about an axis of rotation (A). The stator (22) has end faces (23a, b) and axial through openings (25) which are penetrated by screw bolts (26), each with an external thread section (26b) on one of the internal thread sections (34a) of the support element (30). are set. It is provided that the bolts (26) are designed as fitting screws, one of the fitting screws having a first fitting section (261) with a first outer fitting diameter (262) and a second fitting section (264) with a second outer fitting diameter, and that this Fastening openings (34) of the support element (30) have a third fitting section (341) with a first inner fitting diameter (342) and that the through openings (25) of the stator (22) in the region of the first contact surface (23a) have a fourth fitting section (231) have a second inner fitting diameter (232). The first fitting section (261) and the third fitting section work together to form a first fitting area (27) and the second fitting section (264) and the fourth fitting section (231) form a second fitting area (28).

Description

The invention relates to a structural unit comprising an electrical machine and a support element according to the preamble of patent claim 1.

A generic unit is already from the US 2015/0130311 A1 out. The electrical machine described there comprises a circular stator with a plurality of stator segments, each of which has a circular segment-shaped yoke region with at least one stator tooth projecting radially inward from the yoke region. The stator segments are joined together in a ring to form a stator laminated core, which is enclosed radially on the outside by a stator carrier. To fix the stator to a support element provided as a housing, a plurality of axial through openings are provided for inserting screw bolts which can be screwed into threaded bores of the support element. In the arrangement explained there, these through openings on the stator are formed in separate sleeve-shaped elements which are fixed radially outside on the stator carrier. The stator is thus fixed on one end face of the supporting element by means of the screw bolts.

A precisely fitting connection of two or more components can also be produced in a manner known to the person skilled in the art by means of fitting screws. In addition to a screw head and an external thread section, such fitting screws also have a section with an outer fitting diameter which can interact with an inner fitting diameter of a component and thereby enables a defined, essentially play-free position assignment of the parts.

In particular, in the case of a rotating electrical machine with a rotor to be fixed independently of the stator, there is a need to form an air gap between these elements symmetrically with respect to an axis of rotation of the rotor in order to ensure that the machine runs synchronously. As a result of manufacturing tolerances, it is possible that the through openings in the stator and the threaded bores or holes in the support element are not in alignment with one another and the assembly of the stator of the electrical machine on the support element is thereby made more difficult. If, as a remedy, the through openings are expanded compared to a bolt diameter, the stator can be easily mounted on its support element, however, when the stator is fixed, there may be an asymmetrical arrangement of the stator with respect to the rotor rotating about the axis of rotation due to the existing scope ,

Starting from the explained prior art and the described problem, the invention has for its object to improve a structural unit of the type mentioned that the stator with respect to an axis of rotation of the electrical machine are fixed centered under the influence of tolerances that occur to a support element can.

The object is achieved by a structural unit with the features of patent claim 1. Advantageous refinements and developments of the invention are listed in the dependent claims, as well as in the description and the attached figures.

A structural unit comprising an electrical machine and a support element is thus proposed, the support element comprising a plurality of fastening openings with an internally threaded section and the electrical machine comprising an annular stator and a rotor which is rotatably mounted about an axis of rotation. The stator has a first and a second end-face contact surface and a plurality of axial through openings, which are designed to correspond to the fastening openings and which extend between the contact surfaces. The through openings are penetrated by bolts, which act on the first contact surface of the stator with a screw head and which are each fixed with an external thread section on one of the internal thread sections of the support element, the second contact surface of the stator being loaded in the direction of the contact surface of the support element.

According to the invention it is provided that the screw bolts are designed as fitting screws, one of the fitting screws having a first fitting section with a first outer fitting diameter and a second fitting section with a second outer fitting diameter, and that the fastening openings of the support element have a third fitting section with a first inner fitting diameter Have pass diameters and that the passage openings of the stator in the region of the first contact surface have a fourth pass section with a second inner pass diameter, the first pass section and the third pass section cooperating to form a first pass area and the second pass section and the fourth pass section forming a second Interact with the fitting area.

By providing two fitting areas, it is fundamentally possible to spatially divide the means which are in engagement with one another for a centered arrangement of the stator on the support element, and to space them apart. By creating a mutual spacing of the fitting areas in the event of a mismatch, for example as a result of manufacturing tolerances of the stator and support element, the mismatch can be compensated for over a larger spatial area. As a result, the stresses occurring on the components and / or connecting means involved can be kept low and minimized. Furthermore, the provision of two fitting areas makes it possible in principle to bring the existing fitting sections into engagement with one another either at the same time or one after the other when assembling the structural unit, and to produce or design the fitting areas in a staggered manner over time. This can make assembly easier. To center the stator with respect to the axis of rotation of the rotor, at least three fastening areas explained above are provided.

In the case of the proposed structural unit, the stator can be designed for an electrical machine of the internal rotor as well as the external rotor type. The stator can comprise a laminated core and a stator carrier. The through openings can be formed on the stator, for example in the laminated core or on a stator carrier which surrounds the laminated core or is arranged inside or on an element connected to it. The support element can be present, for example, as a housing and can be designed as a machine or module housing or as a wall element. The structural unit is designed and provided in particular for the use of a drive train of a hybrid or electric vehicle, the electrical machine generating a drive torque for driving the vehicle.

Advantageously, in order to form the broadest possible range of action for reducing a mismatch, the first fitting section faces the free end of the screw bolt and in particular is configured adjacent to the external thread section and the second fitting section faces the screw head and in particular is configured adjacent to the screw head. The fitting sections can therefore be carried out on the bolts as spatially as possible from one another.

Furthermore, the first outer fitting diameter can be of the same size or smaller than the second outer fitting diameter, so that in the latter case the first fitting section can easily be passed through a through opening of the stator and the second fitting section only at a comparatively short distance into the stator trained fourth pass section can be introduced.

When inserting the screw bolts, assembly can be facilitated by the arrangement being designed such that the female thread section follows the third fitting section in an insertion direction of the screw bolt at the fastening opening, with an axial length of the male thread section being greater than an axial length of the third fitting section. When screwing in, the screw bolt first engages the internally threaded section of the support element and only then, when an engagement has already been made, on the third fitting section formed at the fastening opening.

An advantageous temporally staggered generation of the fitting areas can be represented by the arrangement being designed such that, in an insertion direction of the screw bolt, a mutual distance between an insertion position of the first fitting section at the third fitting section and an insertion position of the second fitting section at the fourth fitting section is smaller than a mutual distance between one in Axial limitation of the first fitting section located at the front to an axial limitation of the second fitting section located at the front in the insertion direction. As a result, the second fitting section of the screw bolt only comes into engagement with the fourth fitting section present on the stator when the first fitting section has already been engaged. This measure also serves for easy assembly of the assembly.

Furthermore, a screw bolt can have a shaft section axially between the external thread section and the screw head. With particular advantage, the screw bolt can be formed, at least in sections, with an shank diameter that is smaller than the first outer fitting diameter in an axial region between an axial boundary of the first fitting section located at the rear in the insertion direction and the axial boundary of the second fitting section located at the front. In this way, there is an annular space which, when the screw bolt is screwed in and in the event of a mismatch, serves as a movement space in which the screw bolt can deform or move during tensioning without inadvertently touching the through opening of the stator.

A further ease of assembly can be made possible in that the screw bolt has a guide section with an outer diameter that is larger than the shaft diameter in an axial area between an axial boundary of the first fitting section at the rear in the insertion direction and the axial boundary of the second fitting section located at the front. The guide section advantageously has a smaller diameter than one on the fourth Fitting section adjoining the passage opening of the stator. By providing a guide section, the screw bolt can be pre-centered in relation to the first engagement of the external thread on the internal thread section of the support element, which considerably facilitates threading the screw bolt into its internal thread.

Based on this, the through opening in the region of the second contact surface of the stator can have a recess which extends axially into the stator, the diameter of this recess being larger than a diameter of a section of the through opening located axially between the recess and the fourth fitting section. In particular, an axial extension of the recess and a position and axial extension of the guide section can also be dimensioned such that when the internal thread section and the external thread section are engaged for the first time, the screw bolt is guided by the guide section and that when the screw bolt is further screwed in after engagement Guide section enters the recess and thus the leadership is canceled by the guide section. The guide section is thus free in the inserted state of the screw bolt. To center the arrangement, the bolts can tighten, the free, i.e., between the first and the second fitting section. non-guided section of a bolt can be deformed using the annular space formed around it. In the assembled final state, the guide section is arranged inside the recess.

• 1 eine schematische Darstellung einer Baueinheit aus einer elektrischen Maschine mit einem Stator, der mittels Schraubbolzen an einem Tragelement festgelegt ist;
• 2 eine Einzeldarstellung eines als Passschraube ausgebildeten Schraubbolzens zur Verbindung von Tragelement und Stator;
• 3 eine Darstellung einer Baueinheit gemäß 1 unter Verwendung der Passschraube von 2.

The invention is explained below by way of example using an embodiment shown in the figures.
Show it:

• 1 is a schematic representation of a unit from an electrical machine with a stator, which is fixed by means of bolts on a support element;
• 2 a detailed view of a screw bolt designed as a fitting screw for connecting the support element and stator;
• 3 a representation of a unit according 1 using the fitting screw from 2 ,

1 first shows schematically a unit 10 from an electrical machine 20 and a support element 30 , which in the present case is a gear housing 32 a gear change transmission is formed. The electrical machine 20 can be designed, for example, as a permanently excited synchronous machine or an asynchronous machine of the internal rotor type and comprises a radially outer annular stator 22 and one arranged radially on the inside and about an axis of rotation A rotatably mounted rotor 24 with an active rotor part 24a , a rotor carrier 24b and with a rotor shaft 24c , The electrical machine 20 is part of a drive train of an electric or hybrid vehicle (not shown further here) and serves as a drive source for moving the vehicle.

To fix and center the stator 22 has the gearbox 32 a total of three fastening openings evenly distributed on a pitch circle and extending axially 34 with an internal thread section 34a on. The stator 22 has a stator laminated core 22a with a stator winding 22b on which is from a stator carrier 23 will be carried. The stator 22 , especially the stator carrier 23 comprises a first and a second end-face contact surface 23a . b and further a plurality of axial through holes 25 leading to the mounting holes 34 are formed correspondingly and which are between the contact surfaces 23a . b extend. The through openings 25 are made of bolts 26 penetrated, which with a screw head 26a on the first contact surface 23a of the stator 22 act and which each with an external thread section 26b on one of the internal thread sections 34a of the support element 30 . 32 are defined, the second contact surface 23b of the stator 22 towards a contact surface 32a of the support element 30 is charged. In 1 is the attachment of the stator 22 shown only schematically. The exact special training of the bolts 26 and the attachment points according to the invention is in the 2 . 3 shown and opposite 1 as explained below.

Present are with a view to the 2 . 3 the bolts 26 designed as fitting bolts, with a bolt 26 or one of the fitting screws a first fitting section 261 with a first outer fitting diameter 262 and a second pass section 264 with a second outer fitting diameter 265 having. The mounting openings also point 34 of the support element 30 a third pass section each 341 with a first inner fitting diameter 342 and the through holes 25 of the stator 22 point in the area of the first contact surface 23a a fourth pass section 231 with a second inner fitting diameter 232 on. The first pass section is effective 261 and the third pass section 341 with formation of a first pass area 27 together and the second pass section 264 and the fourth pass section 231 work with the formation of a second pass area 28 together. Like in the 3 recognizable are the two pass areas 27 . 28 spaced apart from each other. The screw head 26a is formed on the contact side with a larger diameter than the fourth pass section 231 ,

The first pass section 261 is the free end of the bolt 26 facing and in particular to the external thread section 26b executed adjacent. The second pass section 264 is the screw head 26a facing and in particular adjacent to the screw head 26a educated. The pass sections 261 . 264 are thus on the bolts 26 as spatially separated as possible.

Furthermore, the first outer fitting diameter 262 smaller than the second outer fitting diameter 265 trained so that when assembling the stator 22 the first pass section 261 easily through one of the through openings 25 of the stator 22 can be passed through. The second pass section 264 needs only at a comparatively short distance in the on the stator 22 trained fourth pass section 231 to be introduced.

The arrangement is designed such that in an insertion direction M of the bolt 26 at the mounting hole 34 the internal thread section 34a to the third pass section 341 follows. Here is an axial length 260b of the external thread section 26b greater than an axial length L3 the third pass section 341 , The bolt 26 can thus be screwed in first on the internal thread section 34a of the support element 30 attack and only afterwards when an intervention has already been made on the fastening opening 34 trained third pass section 341 ,

The unit 10 is further designed so that in an insertion direction M of the bolt 26 a mutual distance A1 an axial insertion position E1 the first pass section 261 ( 3 ) on the third pass section 341 to an insertion position E2 the second pass section 264 on the fourth pass section 231 is smaller than a mutual distance A2 one in the direction of insertion M front axial limit 261a the first pass section 261 to one in the direction of insertion M front axial limit 264a the second pass section 264 ( 2 ). This brings the second fitting section of the bolt 26 only in engagement with the fourth, on the stator 22 present passport section 231 if the first pass section is already engaged 261 is done.

With a view to 2 has the bolt 26 axially between the external thread section 26b and the screw head 26a a shaft section 26d on. The bolt 26 is in an axial area between one in the direction of insertion M rear axial limit 261b the first pass section 261 and the front axial limit 264a the second pass section 264 at least in sections with a compared to the first outer fitting diameter 262 smaller shaft diameter 260d educated. In this way, there is between the bolt 26 and through opening 25 an annulus 36 ( 3 ). This annulus 36 serves when screwing in the bolt 26 and also in the case of a mismatch as a space in which the screw bolt is located 26 can deform or move when clamped in without accidentally touching the through opening 25 of the stator 22 to get.

Furthermore, the screw pin 26 in an axial area between one in the direction of insertion M rear axial limit 261b the first pass section 261 and the front axial limit 264a the second pass section 264 a guide section 38 with a compared to the shaft diameter 260d larger outside diameter 38a on.

The outside diameter 38a is smaller than the inner fitting diameter 232 the fourth pass section 231 or as a diameter 25a a section of the through opening adjoining this 25 , The passage opening 25 is present except for an end section explained below with the fitting diameter 232 the fourth pass section 231 educated. Through the guide section 38 the bolt can 26 compared to the first engagement of the external thread 26b on the internal thread section 34a of the support element 30 be centered.

The passage opening 25 points in the area of the second contact surface 23b of the stator 22 a recess extending axially into this 40 on, their diameter 40a is larger than a diameter 25a one axially between the recess 40 and the fourth pass section 231 located section of the through opening 25 , The diameter is present 40a larger than the diameter 232 the fourth pass section 231 , There is an axial extension 40b the recess 40 as well as an axial position and an axial extension 38b of the guide section 38 dimensioned so that when the internal thread section is engaged for the first time 34a and male thread section 26b another guide of the bolt 26 through the guide section 38 takes place and that when the screw bolt is screwed in further 26 after engagement, the guide section 38 into the recess 40 occurs and thus the leadership through the leadership section 38 will be annulled. The leadership section 38 is in the inserted state of the bolt 26 Consequently optional. For centering the stator 22 can the bolts 26 tighten when screwing in, the between the first and the second fitting section 261 ; 264 located free, ie not guided section of one of the bolts 26 taking advantage of the annular space formed around it 36 can be deformed. As can be seen, the guide section 38 in the assembled final state of the stator 22 still inside the recess 40 arranged.

LIST OF REFERENCE NUMBERS

10

unit

20

electrical machine

22

stator

22a

stator lamination

22b

stator

23

stator

23a, b

contact surface

231

fourth pass section

232

second inner pass diameter

24

rotor

24a

active rotor part

24b

rotorarm

24c

rotor shaft

25

Through opening

25a

diameter

26

bolts

261

first pass section

261a

axial limitation

261b

axial limitation

262

first outer fitting diameter

264

second pass section

264a

axial limitation

265

second outer fitting diameter

26a

screw head

26b

Externally threaded section

260b

axial length

26d

shank portion

260d

Shaft diameter

27

first pass area

28

second pass area

30

supporting member

32

gearbox

34

fastening opening

341

third pass section

342

first inner pass diameter

34a

Internally threaded portion

36

annulus

38

guide section

38a

outer diameter

38b

axial extension

40

recess

40a

diameter

40b

axial extension

A

axis of rotation

A1

distance

A2

distance

E1

insertion

E2

insertion

M

insertion

L3

axial length

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included 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

• US 2015/0130311 A1 [0002]

Claims (9)

Assembly (10) comprising an electrical machine (20) and a support element (30), the support element (30) comprising a plurality of fastening openings (34) with an internally threaded section (34a), - the electrical machine (20) an annular stator (22) and a rotor (24) rotatably mounted about an axis of rotation (A), - the stator (22) has a first and a second end-face contact surface (23a, b) and a plurality of axial through openings (25), which to are corresponding to the fastening openings (34) and extend between the contact surfaces (23a, b) and wherein - the through openings (25) are penetrated by screw bolts (26) which - with a screw head (26a) onto the first contact surface (23a) of the stator (22) act and which are each fixed with an external thread section (26b) to one of the internal thread sections (34a) of the support element (30), the second contact surface (23b) of the stator (22) in R Sealing a contact surface (32a) of the support element (30), characterized in that - the screw bolts (26) are designed as fitting screws, - one of the fitting screws having a first fitting section (261) with a first outer fitting diameter (262) and one has a second fitting section (264) with a second outer fitting diameter and that - that the fastening openings (34) of the support element (30) have a third fitting section (341) with a first inner fitting diameter (342) and that - the through openings (25) of the stator (22) in the area of the first contact surface (23a) have a fourth fitting section (231) with a second inner fitting diameter (232), wherein - the first fitting section (261) and the third fitting section work together to form a first fitting area (27) and wherein - The second fitting section (264) and the fourth fitting section (231) cooperate to form a second fitting area (28). Unit according to Claim 1 , characterized in that the first fitting section (261) faces the free end of the screw bolt (26) and in particular is adjacent to the external thread section (26b) and in that the second fitting section (264) faces the screw head (26a) and in particular is adjacent to the Screw head (26a) is formed. Unit according to Claim 1 or 2 , characterized in that the first outer fitting diameter (262) is equal to or smaller than the second outer fitting diameter (265). Unit according to one of the Claims 1 to 3 , characterized in that in an insertion direction (M) of the screw bolt (26) at the fastening opening (34) the internal thread section (34a) follows the third fitting section (341), an axial length (260b) of the external thread section (26b) being greater as an axial length (L3) of the third fitting portion (341). Unit according to one of the Claims 1 to 4 , characterized in that in an insertion direction (M) of the screw bolt (26) there is a mutual distance (A1) between an insertion position (E1) of the first fitting section (261) on the third fitting section (341) and an insertion position (E2) of the second fitting section (264 ) at the fourth fitting section (231) is smaller than a mutual distance (A2) between an axial boundary (261a) at the front in the insertion direction (M) of the first fitting section (261) and an axial boundary (264a) at the front in the insertion direction (M) second pass section (264). Unit according to one of the Claims 1 to 5 , characterized in that the screw bolt (26) at least in an axial area between an axial boundary (261b) of the first fitting section (261) located at the rear in the insertion direction (M) and the axial boundary (264a) of the second fitting section (264) located at the front is designed in sections with a smaller shaft diameter (260d) than the first outer fitting diameter (262). Unit according to Claim 6 , characterized in that the screw bolt (26) has an axial area between an axial boundary (261b) of the first fitting section (261) located at the rear in the insertion direction (M) and the axial boundary (264a) of the second fitting section (264) located at the front Guide section (38) with an outer diameter (38a) larger than the shaft diameter (260d). Unit according to one of the Claims 1 to 7 , characterized in that the through opening (25) in the region of the second contact surface (23b) of the stator (22) has a recess (40) which extends axially into the stator (22), a diameter (40a) of this recess (40) is larger than a diameter (25a) of a section of the through opening (25) located axially between the recess (40) and the fourth fitting section (231). Unit according to Claim 8 , characterized in that an axial extension (40b) of the recess (40) and an axial position and an axial extent (38b) of the guide section (38) is dimensioned such that when the internal thread section (34a) and the external thread section (26b) engage, the screw bolt (26) is guided by the guide section (38) and that it is screwed in further of the screw bolt (26), after the engagement has taken place, the guide section (38) enters the recess (40) and the guide is thus canceled by the guide section (38).

Images