Center housing of a turbocharger

p0001The present invention relates to a bearing housing of a charging device, in particular a bearing housing of an exhaust turbocharger, according to the preamble of claim 1. The invention also relates to an equipped with such a bearing housing charging means.

p0002From the <patcit id="pcit0001" dnum="DE202008014925U1"><text>DE 20 2008 014925 U1</text></patcit> is a generic bearing housing with a bearing housing cover known, via which a thrust bearing for a shaft of the charging device is fixed in the axial direction. An attachment of the bearing housing cover to the housing situation is via a locking ring, which in the mounted state in a radially split, partial in the bearing housing cover and formed partially in the bearing housing groove is disposed. In addition, a spring element is provided in order to allow on the one hand a resilient bias and on the other hand a certain tolerance compensation between the thrust bearing and the bearing housing cover.

p0003From the <patcit id="pcit0002" dnum="EP0599520B1"><text>EP 599 520 B1 0</text></patcit> is another generic bearing housing is known, in which a bearing housing cover is also fastened by means of a locking ring on the bearing housing.

p0004Finally, it is also from the <patcit id="pcit0003" dnum="WO2008042698A1"><text>WO 2008/042698 A1</text></patcit> known a bearing housing for a charging device.

p0005The present invention deals with the problem of providing a bearing housing of the generic type, an improved or at least provide an alternative embodiment which is in particular constructively simpler design.

p0006The invention is based on the general idea, in a bearing housing of a loading device, particularly in a bearing housing of a turbocharger to provide an undercut-like annular groove in which a spring-plate-like securing element, for example a circlip, engages with its outer periphery, in itself this spring plate-like securing element with its inner edge a bearing housing is supported and resiliently biases or fixed on this, a thrust bearing for a shaft of the charging device in the axial direction. In known from the prior art bearing housings often a safety ring and additionally a spring element is provided, wherein the locking ring only had the axial preload the thrust bearing to the object, the axial fixation of the bearing housing cover and usually provided between the bearing housing cover and the thrust spring element. Accordingly, at least two elements for spring loading and fixation of the thrust bearing were required in known from the prior art bearing housings, which will now be effected at the bearing housing according to the invention exclusively by a single element, namely in the spring plate-like securing element. This spring plate-like securing element thus fixes both the bearing housing cover and the thrust bearing in the axial direction and clamped at the same time the bearing housing cover axially against the thrust bearing before, so that the latter can preferably be maintained throughout the life of the charging device reliably in position. Of course, while the bearing housing cover additionally comprise an anti-twist device, which prevents a rotation thereof about its axis. With the bearing housing according to the invention it is thus possible to obtain the same effects as those known from the prior art bearing housing, namely, the axial fixing and spring preload of the axial bearing, only structurally much simpler and cheaper.

p0007In an advantageous development of the inventive solution, the fuse element at the outer edge radial incisions, which divide the outer edge in individual snap hooks. This allows in particular an installation of the security element according to the invention in the bearing housing easier, since an installation force, i.e. a force acting on the securing element in the axial direction pressing force can be significantly reduced. The individual snap hooks can thereby bend more easily due to the between which are arranged radial cuts than would be in a closed outer edge of the case, the locking effect of the spring-plate-like securing element is not affected, since the installed state engage all snap hooks into the undercut-like groove and thereby the securing element prevent it from accidental loosening reliable.

p0008Advantageously, the radial incisions are rounded at a radially inner end. Such fillets have fracture mechanical advantages, especially as the occur in notches or edges voltage critical zones can be avoided by rounding.

p0009In a further advantageous embodiment of the inventive solution, the bearing housing cover on at least one pocket into which a tool for dismantling the security element is introduced. During maintenance or replacement of the thrust bearing, it is advantageous if the security element is simply removed and thereby the thrust bearing can be removed. The at least one provided on the bearing housing cover case allows it to engage behind the securing element, which then, for example, with a corresponding hook element can be withdrawn from the undercut connection easy. The bag according to the invention can be designed as a simple recess and, for example by forming methods together with the bearing housing cover.

p0010Further important features and advantages of the invention will be apparent from the dependent claims, from the drawings and from the associated figure description with reference to the drawings.

p0011It is understood that the features mentioned above and those yet to be explained not only in the particular combination indicated but also in other combinations or alone without departing from the scope of the present invention.

p0012Preferred embodiments of the invention are illustrated in the drawings and are explained in the following description, wherein like reference numerals refer to identical or similar or functionally identical components.

p0013In the drawings, schematically:<dl id="dl0001"><dt>Fig. 1</dt><dd>a view and a sectional view through an inventive bearing housing,</dd><dt>FIG. 2</dt><dd>a detail of the left panel in <figref idrefs="f0001">Fig. 1</figref>.</dd><dt>Fig. 3</dt><dd>two views of a fuse element with the inventively provided radial incisions,</dd><dt>Fig. 4</dt><dd>a fuse element in another embodiment and a sectional illustration and a view of a bearing housing with such a security element,</dd><dt>Fig. 5</dt><dd>a sectional view of a bearing housing cover, </dd><dt>Fig. 6.7</dt><dd>Further possible embodiments of the security element.</dd></dl>

p0014According to <figref idrefs="f0001">Fig. 1, 2</figref> and <figref idrefs="f0002">4</figref> has an inventive bearing housing 1 a charging device not otherwise shown, for example, an exhaust gas turbocharger, a bearing housing cover 2 through which a thrust bearing 3 is fixed to a shaft 4 in the axial direction. 5 The bearing housing 1 has an undercut-shaped groove 6, into which a spring-plate-like securing element 7, 7 '(see. In particular the<figref idrefs="f0002">Fig. 3</figref> and the right view of the representation <figref idrefs="f0002">Fig. 4</figref>) Engages with an outer edge. 8 With an internal edge 9 is supported the spring-plate-like securing element 7, 7 'on the bearing housing cover 2 from and clamped against this before the thrust bearing 3 and the bearing housing against the first Unlike known from the prior art bearing housing, in which a fuse element and a spring element are separately formed, this will, 7 'taken over, wherein the fuse element 7, 7' at the same time from the spring plate-like securing element 7 in the bearing housing 1 of the invention preferably is adapted to that the required for proper mounting of the shaft 4 prestressing force is maintained on the thrust bearing 3 over the entire service life of the charging device. The formation of the fuse element 7,7 'in the manner of a disk spring also allows the application of high spring forces over a short distance only.

p0015Considering the safety element 7 in accordance with the <figref idrefs="f0001 f0002">Fig. 1-3</figref>So you can see that this has on the outer edge 8 radial incisions 10, which divide the outer edge 8 into individual snap hooks 11th At a radially inner end of the radial incisions 10, these are preferably rounded in order to reduce or intercept particularly critical voltage spikes. In contrast, the fuse element 7 'as it according to the<figref idrefs="f0002">Fig. 4</figref> is shown provided with an outer edge 8 which has no radial incisions 10 and thus no snap fit eleventh The outer edge 8 of the security element 7 'is thus formed is closed.

p0016To the fuse element 7, 7 'total as efficiently as possible and thus also be able to manufacture inexpensive, this is preferably formed as a steel plate molded part. For reliable preload the thrust bearing 3 is the securing element 7, 7 'either force a form-fitting installed in the bearing housing. 1 The positive connection between the securing element 7, 7 'and the bearing housing 1, for example, achieved this by means of a press excess.

p0017Both the locking element 7 and the fuse element 7 'are formed rounded at its outer edge 8, which in particular the assembly of the respective fuse element 7, 7' considerably simplified because only a smaller axial compressive force during insertion into the bearing housing 1 is required. At the same time a resistance to unintentional can by the rounded design of the outer edge 8 solve the outer edge 8 ensures from the annular groove. 6 The rounded design of the outer rim 8 is also a self-centering it reaches the fuse element 7, 7 'during installation into the bearing housing 1, whereby the assembly can also be simplified. This benefit can also attaching a chamfer to support the self-centering effect. Looking specifically at the<figref idrefs="f0001">FIG. 2</figref> and <figref idrefs="f0002">4</figref>, So it can be seen that the annular groove is substantially complementary 6, 7 'is formed to the outer edge 8 of the fuse element 7 and thereby already produced an optimal connection.

p0018In the <figref idrefs="f0001">FIG. 2</figref> is attached to the bearing housing cover 2 to detect a pocket 12 into which a tool for disassembling the fuse element 7, can be inserted 7 '. This bag 12 is, like the entire bearing housing cover 2 preferably made without cutting.

p0019For assembly of the fuse element 7, 7 'in the bearing housing 1, it is first applicable pressed under application of a thrust force in the direction of the bearing housing cover 2 until it engages with its outer edge 8, in particular with the arranged there snap hook 11 in the bearing casing side groove. 6 The fit is thereby achieved over the outer edge 8, but at least two arranged there snap hooks 11 while the traction generated for example through a press interference. The of the spring plate-like securing element 7, 7 'biasing force applied in particular serves to compensate for axial tolerances, being 8 pressed harder with an increase of biasing force, for example by operating forces, the outer edge of the annular groove 6, thereby forming a self-locking occurs. By inventively embodied securing element 7, 7 'can be achieved very high holding forces.

p0020To remove the fuse element 7, 7 'is a purpose necessary and not shown tool introduced in the space provided on the bearing housing cover 2 pockets 12 which the securing element 7, 7' engage behind and thereby are able to this pry from the annular groove. 6

p0021Since the bearing housing cover 2 is preferably made without cutting, an annular groove is provided there may 6 'have no undercut, but must instead have Ausformungsschrägen.

p0022This according to the <figref idrefs="f0003">Fig. 6</figref> shown securing element 7 has a conical shape in cross section and thereby to absorb axial forces in the manner of a plate spring in position. Due to its zigzag-shaped formation (meandering circumferentially course) it can similarly be a snap ring mounted, that is, he has at least a slight sag in the radial direction, although it is closed in the circumferential direction.

p0023The fuse element 7 according to the <figref idrefs="f0003">Fig. 7</figref> is open in the circumferential direction, similar to a snap ring and has a well spring-like shape, ie axial forces must be included in the location.

p0024In general can be achieved the following significant benefits to the bearing housing 1 according to the invention:<ul><li>Elimination of bolts and corresponding holes and threads for securing the bearing housing cover 2,</li><li>low warpage of shaft seal holes,</li><li>only one sealing point,</li><li>Chipless the bearing housing cover 2 possible</li><li>low construction, but high holding forces,</li><li>easy construction,</li><li>Compensating thermal expansions possible.</li></ul>