DE102017123314B4 - Shift dome of a gear change transmission of a motor vehicle - Google Patents

Abstract

The invention relates to a shift dome (1) of a gear change transmission of a motor vehicle with a housing (2) and a shift shaft (3), wherein the shift shaft (3) in the housing (2) by means of a bearing assembly (4) is mounted, wherein between the housing ( 2) and the switching shaft (3) a seal (5) is operatively arranged to seal an outer first space (I) against an inner, second space (II), wherein the seal (5) in the housing (2) is arranged and Has at least one sealing lip (6) which bears sealingly against the switching shaft (3). In order to permanently prevent the escape of oil from the switching dome, even under harsh environmental conditions, the invention provides that further an element (8) is provided, which is arranged between the seal (5) and the bearing assembly (4) and at the Switching shaft (3) or on the housing (2) is arranged and the housing (2) or the switching shaft (3) forms a radial sealing gap (9).

Description

Field of the invention

The invention relates to a shift dome of a gear change transmission of a motor vehicle having a housing and a selector shaft, wherein the selector shaft is mounted in the housing by means of a bearing assembly, wherein between the housing and the selector shaft, a seal is effectively arranged to an outer first space against an inner, second Seal space, wherein the seal is arranged in the housing and has at least one sealing lip which on the shift shaft ( 3 ) sealingly.

Background of the invention

In the DE 10 2008 029 262 A1 is a generic shift dome for a change-speed gearbox described in which a shift shaft is mounted in a housing. The interior of the switching dome is heavily loaded by spray oil, oil mist or oil foam, so that the friction-optimized seal of the type described here is not always sufficient.

In the field of application of the sealing arrangement in question at Schaltdomen is primarily about retaining spray oil, oil mist and possibly oil foam in the gear compartment and to prevent media entry from the outside into the housing.

In 1 is to be seen a solution according to the prior art. There is a section of a switching dome 1 a gear change transmission, in which in a housing 2 a shift shaft 3 is stored. The bearing of the switching shaft 3 takes place by means of a bearing arrangement 4 which is a socket 10 that is in the housing 2 is attached.

To seal the outer, first room I opposite the inner, second room II is a seal 5 provided a sealing lip 6 and a dust lip 7 includes.

A sealing lip 6 the seal 5 is frictionally on the outer circumference of the shift shaft 3 to accomplish said sealing function. Another, to the room I oriented lip 7 acts as dust lip, protects against the penetration of larger dust and dirt particles and is not on the stem 3 but has minimal air.

The seal 5 includes in a conventional manner a seal carrier 11 in the case 2 attached, preferably pressed, is.

It has been found that, especially when using a vehicle in harsh environmental conditions, such as those encountered in off-road driving, soiling is the area of the seal 5 pressurize so that the sealing function is no longer ensured.

In particular, in the case of the oil, the oil can 6 no longer reliable and over the entire circumference of the shift shaft 3 is applied, via the bearing assembly 4 upwards from the inside of the case 2 escape, so that a corresponding leakage occurs.

DE 10 2011 085 377 B3 shows a vent cap for a transmission that is mountable to a shift dome. DE 100 64 918 A1 discloses a switching dome with a pressed sheet metal sealing cover. They too do not suffice.

Object of the invention

The present invention has the object of providing a generic switching dome in such a way that even in harsh environmental conditions permanently the escape of oil from the switching dome can be reliably prevented.

Presentation of the invention

This object is achieved by the switching dome with the features of claim 1.

The further sealing element may be formed as an O-ring.

An alternative possibility provides that the further element in the radial section is V-shaped; the part of the element directed towards the selector shaft acts as a sealing lip.

Another alternative provides that the further element is formed rectangular in radial section. In this case, the further element is preferably made of plastic.

The radial sealing gap preferably lies between 0.05 mm and 1.0 mm, particularly preferably between 0.1 mm and 0.3 mm.

The further element is preferably on the component (in particular the switching shaft) to which the radial sealing gap is not formed, sealingly or largely sealingly.

The bearing assembly is usually designed as a rolling bearing, which comprises a bushing which is fixed in the housing.

The seal usually comprises a seal carrier which is mounted in the housing.

Due to the inventive design of the switching dome and especially its sealing arrangement, a labyrinth is formed in addition to the actual lip seal, which is effective between the bearing and the (lip) sealing ring and ensures that even in the event that the function of the lip seal is not completely satisfied, no oil or only an acceptable amount of oil escapes from inside the switching dome.

In particular, even when the motor vehicle is used in harsh environmental conditions on bad roads or in the field, oil can no longer so easily pass out of the switching dome via the sealing arrangement.

list of figures

• 1 im Radialschnitt einen Teil eines Schaltdoms eines Zahnräderwechselgetriebes mit einer Dichtungsanordnung, die zwischen einem Gehäuseteil und einem Wellenteil platziert ist, wobei eine Lösung nach dem Stand der Technik dargestellt ist,
• 2 im Radialschnitt einen Teil des Schaltdoms mit einer Dichtungsanordnung, die gemäß einer ersten Ausführungsform der Erfindung ausgebildet ist,
• 3 im Radialschnitt einen Teil des Schaltdoms mit einer Dichtungsanordnung, die gemäß einer zweiten Ausführungsform der Erfindung ausgebildet ist,
• 4 die vergrößerte Darstellung eines Ausschnitts aus 3,
• 5 im Radialschnitt einen Teil des Schaltdoms mit einer Dichtungsanordnung, die gemäß einer dritten Ausführungsform der Erfindung ausgebildet ist, und
• 6 die vergrößerte Darstellung eines Ausschnitts aus 5.

The figures show:

• 1 in radial section a part of a switching dome of a gear change transmission with a sealing arrangement which is placed between a housing part and a shaft part, wherein a solution according to the prior art is shown,
• 2 in radial section a part of the switching dome with a sealing arrangement, which is formed according to a first embodiment of the invention,
• 3 in radial section a part of the switching dome with a sealing arrangement, which is formed according to a second embodiment of the invention,
• 4 the enlarged view of a detail from 3 .
• 5 in radial section a part of the switching dome with a sealing arrangement, which is formed according to a third embodiment of the invention, and
• 6 the enlarged view of a detail from 5 ,

Detailed description of the figures

In 2 is analogous to the solution according to the prior art according to 1 a first embodiment of the invention shown. Again, the case is 2 of the switching dome 1 to see where a shift shaft 3 is stored, including the bearing assembly 4 serves. The bearing arrangement 4 allows a rotation of the switching shaft 3 relative to the housing and their displacement in the longitudinal direction of the switching shaft 3 , The seal 5 In turn, as in the prior art, includes the sealing lip 6 at the outer periphery of the stem 3 starts and thus fulfills the sealing function. Furthermore, there is a dust lip 7 provided that no contact with the switching shaft 3 Has. Also the further embodiment concerning the socket 10 the bearing arrangement 6 as well as the seal carrier 11 are related as above 1 described the desired sealing effect between the first room I and the second room II to accomplish.

It is essential now that in addition to the seal 5 another (sealing or labyrinth) element 8th is provided. This is between the seal 5 and the bearing assembly 4 arranged. The further element 8th is at the switching shaft 3 arranged and forms the housing 2 a radial sealing gap 9 ,

According to the embodiment 2 is the other element 8th designed as an O-ring, with a slight interference fit the shift shaft 3 covers and thus sits on this. The dimensions of the O-ring are chosen so that for the radial sealing gap 9 gives a value of about 0.2 mm.

In the 3 and 4 a second embodiment of the invention is shown. In contrast to 2 is now provided that the further element 8th is designed here in the form of a sealing ring or a sealing lip, which has a V-shaped contour in radial section. With the radially inner periphery of the element lies 8th with a slight interference fit on the outer circumference of the selector shaft 3 and in turn forms with its outer periphery a small radial sealing gap 9 to the housing 2 , which in turn is in the range of about 0.2 mm.

In the 5 and 6 Finally, a third embodiment of the invention is shown. Here is the other element 8th formed as a plastic ring, which has a rectangular shape in the radial section. The element 8th again lies with the smallest possible clearance on the shift shaft 3 and forms the housing to the radial sealing gap 9 which in turn is of the order of magnitude.

Due to the small sealing gap 9 ensures that the friction of the arrangement is not or only minimally increased. As a result of the further element 8th Oil could only through a detour (and thus in the manner of a labyrinth seal) to the actual seal 5 arrive, so that there is an increased security against leakage of oil from the switching dome.

A radial interference fit or contact with the switching dome housing 2 through the further element 8th is avoided in order not to increase the friction in the system, even if the shift shaft 3 subjected to bending moments or bending deformations at higher load.

LIST OF REFERENCE NUMBERS

1

switch dome

2

casing

3

shift shaft

4

bearing arrangement

5

poetry

6

sealing lip

7

dust lip

8th

further element (sealing element)

9

radial sealing gap

10

Bushing of the bearing assembly

11

seal carrier

I

first room

II

second room

Claims (9)

Shift dome (1) of a gear change transmission of a motor vehicle with a housing (2) and a switching shaft (3), wherein the switching shaft (3) in the housing (2) by means of a bearing assembly (4) is mounted, wherein between the housing (2) and the A seal (5) is operatively arranged to seal an outer first space (I) against an inner, second space (II), wherein the seal (5) in the housing (2) is arranged and at least one sealing lip ( 6) sealingly abutting the switching shaft (3), further comprising an element (8) disposed between the seal (5) and the bearing assembly (4), characterized in that the further element (8) is arranged on the switching shaft (3) and the housing (2) forms the radial sealing gap (9). Switching dome to Claim 1 , characterized in that the further element (8) is formed as an O-ring. Switching dome to Claim 1 , characterized in that the further element (8) is formed in radial section V-shaped. Switching dome to Claim 1 , characterized in that the further element (8) is rectangular in radial section. Switching dome to Claim 4 , characterized in that the further element (8) consists of plastic. Switching dome according to one of the Claims 1 to 5 , characterized in that the radial sealing gap (9) is between 0.05 mm and 1.0 mm, preferably between 0.1 mm and 0.3 mm. Switching dome according to one of the Claims 1 to 6 , characterized in that the further element (8) on the component (2, 3), to which the radial sealing gap (9) is not formed, sealingly or largely sealingly abuts. Switching dome according to one of the Claims 1 to 7 , characterized in that the bearing assembly (4) is formed as a rolling bearing, which comprises a bushing (10) which is fixed in the housing (2). Switching dome according to one of the Claims 1 to 8th , characterized in that the seal (5) comprises a seal carrier (11) which is fixed in the housing (2).

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