DE102005008006A1 - Dual mass flywheel, comprising counter bearing arrangement for inner ring and lubricant compartment - Google Patents

Abstract

The primary (2) and the secondary mass (3) can be rotated in relation to each other using a friction bearing (6) with an outer (7) and an inner ring (8) accommodating the ball elements (9). The inner ring (6) comprises a contact segment (10) and a bearing segment (11) supported against the front edge of the bearing carrier (4). The outer ring (7) has a u-shaped cross section forming a lubricant compartment (13) in combination with the bearing carrier (4). A slide bearing (6) is positioned between the outer ring (7) and the inner ring (8).

Description

Territory of invention

The The invention relates to a dual mass flywheel for a motor vehicle, with a primary mass and a secondary mass, the above at least one rolling bearing with an inner ring and an outer ring, between which rolling elements are guided, rotatable connected to each other.

background the invention

One Dual mass flywheel is a torsional vibration damper that especially in motor vehicles between the internal combustion engine and the transmission is switched. It consists of a directly with the output shaft of the internal combustion engine connected primary mass and one over the coupling coupled to the input shaft of the transmission Secondary mass, both over a steaming Carrier system in the form of usually two opposite ones, coupled curved compression springs. Both masses are over one roller bearing rotatable with respect to stored each other. When operating the motor vehicle is on the rotating crankshaft the primary mass actively driven, over the driver dampers becomes the secondary mass taken along, which in turn drives the transmission input shaft. The is called, During operation, the entire dual mass flywheel rotates. Beyond the spring driver dampers on the one hand rotational irregularities, which will become the driver damper on the one hand rotational irregularities, which result from imbalances of the masses, muffled, but also to the other irregularities the internal combustion engine. The rotatable storage connected to the Damping over the Federmitnehmer allows a twisting of the two masses to each other, the nonuniformities to compensate. The occurring maximum oscillating swivel angle is while the ride about 0.4 °. That is, that roller bearing is during of the usual Operation hardly dynamically stressed in terms of relative speed. Different, however, when starting the vehicle, where it becomes an oscillating Swing angle of +/- 60 ° come can. Here, therefore, takes place an actual stronger rotation of the primary with respect to the Secondary mass. The function of such dual mass flywheels is known per se and does not require a detailed description.

In front In all cases, a storage system with very low friction, So with a very low coefficient of friction, preferably <0.05 desired. a you can basically do that with a rolling bearing achieve. As a result, primarily special ball bearings in the form so-called ZMS or DFC bearings used, which are special bearings, in the Production due to the design the bearings as solid bearings and the use of expensive plastic caps to guarantee the required tightness are very expensive. The plastic caps are over it In addition, very sensitive during assembly, which is why the bearings also light damaged when they are used. Also is an integration in the very small space, not least due to the demand that Camp as possible far away from the clutch-side friction surfaces to avoid an inadmissibly strong warming of the warehouse narrow and close to the axis of rotation is difficult. alternative For this purpose it is known to use a plain bearing instead of a rolling bearing. However, such a plain bearing has a relatively high coefficient of friction on, about it can out axial forces, on the bearing in particular when operating the downstream Clutch act, over a slide bearing is not or only partially absorbed. Admittedly Slide bearing the utilization of the existing, very small space to, that is, the integration of a plain bearing in the very narrow space is readily possible, However, plain bearings are given the mechanical requirements often not up to scratch and wear out, especially with regard to on given rolling and wobbling movements of the secondary mass, which lead to an imbalance and too local do not lead high Herz'schen-pressing grown.

to Interruption of the heat flow in the region of the friction points, it is expedient on the outer diameter of the outer ring for heat insulation a plastic sleeve to provide, or the outer ring with a thermally insulating Coat layer.

Further it is appropriate, at least the cylindrical inner diameter of the inner ring, in contact with the cylindrical bearing carrier stands, with a hard chrome layer, a nickel layer or a Anti-friction coating to avoid tribocorrosion or fit corrosion to coat.

Summary the invention

Of the The invention is thus based on the problem of a dual mass flywheel for a Specify motor vehicle over a rolling bearing is stored over the high axial forces can be recorded and with warranty a very low coefficient of friction in the very small existing space can be integrated, and a suitable for this purpose roller bearing specify.

Of the The first part of the problem underlying the invention is at a dual mass flywheel of the type mentioned in the present invention solved, that rotates on a cylindrical bearing carrier of the primary mass arranged inner ring for receiving axial forces on the front side of the cylindrical bearing support is opposed, and the rolling bearing an at least partially extending axially along the bearing carrier, having sealed lubricant receiving space.

The provided according to the invention front axial bearing of the bearing, which is a very low Has friction, allows it, from the secondary mass for example, when pedaling the clutch pedal initiated axial personnel without further ado. The axially extending lubricant receiving space Ensures that sufficient lubricant is always available. Since he is axially along of the bearing carrier extends, and there, as further provided according to the invention, the rolling elements in axial direction seen in front of the abutting end face or seen in the radial direction above the abutting end face, is the total radial height of the rolling bearing relatively low, so that integration into the very narrow Space between the bearing carrier as part of the primary mass and the subsequent secondary mass is given, possible is.

The suitable rolling bearings is also relatively easy and inexpensive to produce, after it as described only with a maximum oscillating swing angle when starting about +/- 60 ° and while the driving operation of approx. +/- 0,4 °, which is why not too big accuracy requirements have to be asked. It is therefore easily possible the rolling bearing forming essential parts in a cost effective, easy way to manufacture. The components can pulled, pressed or made by cutting and possibly be reworked, for example, by grinding or hardening or like. It is not necessary in any case, the parts in costly manufacturing processes such as solid or the like or using expensive materials as in the case to make the DFC bearing of the expensive plastic cap housing. Rather, it is it is possible that rolling bearings very inexpensive to produce.

Especially is appropriate it, if the rolling bearing combined with a plain bearing. About this slide bearing can additionally the radial bearing of the secondary mass be obtained. The use of a plain bearing, here only one radial bearing function is, in the inventive dual-mass flywheel readily possible after the predominant axial forces as stated above be received frontally arranged bearings.

Next the dual mass flywheel itself, the invention further relates roller bearing for a dual mass flywheel of the type described above. The rolling bearing has an inner ring, an outer ring and guided between them Rolling elements on and is characterized by the fact that on the inner ring an abutment section is formed, with which the inner ring axially on an abutment, namely the front side of the primary mass side arranged cylindrical bearing support, can be fixed, that a cylindrical, axially extending bearing portion provided is over the rolling bearing on a cylindrical bearing carrier is fixable, and that the rolling bearing an at least partially axially along the bearing carrier (in as seen in the assembly position), sealed lubricant receiving space having. The plant section can be defined by any step or edge-like diameter variation can be realized on the inner ring, which is suitable, the inner ring and thus the bearing itself axially on the abutment, so just the front side of the cylindrical bearing carrier of primary mass set.

The Rolling elements lie seen axially before the contact portion or radially above the same, so that in total, especially in axial arrangement a very low bearing height in radial direction results.

Of the outer ring itself can in the axial direction one or both sides of a rolling element leading Extended section be and with the one or both sides axially extended Inner ring and / or at least one, preferably annular and cap-like, sealing element to form a lubricant receiving space. Such a sealing element, of course, depending on the design be provided on both sides. In addition to using an annular and cap-like sealing element, which seals the bearing to the side realized, of course, can also an annular one Sealing lip, which seals, be provided or any other sealing means such as felt rings or the like, as long as a Ensures sufficient sealing of the lubricant receiving space is.

In Development of the invention can be used to form a in axial Direction as possible be provided compact bearing that the axial bearing section connects to the plant section.

It is also expedient if the rolling bearing is combined with a sliding bearing, wherein the two bearing sections have different functions. During that the actual Rolling bearing area forming portion has the function of absorbing axial forces, the sliding bearing serves for the radial storage of the secondary mass.

A first alternative of the invention to form a combined rolling bearing It provides that the outer ring is executed in cross-section substantially U-shaped and sleeve-like and provided on its radially inner leg, the sliding bearing is. This slide bearing acts in this embodiment to the inner Cylinder wall of the cylindrical bearing carrier out, this cylindrical Bearing carrier attacks almost in the one ring-shaped Receiving groove having combined rolling plain bearings. alternative to This embodiment of the invention, the sliding bearing but also on outer ring be provided and - in the mounting position - radial inside to the outside wall store the cylindrical bearing section or towards the inner ring.

Short description the drawings

Further Advantages, features and details of the invention will become apparent the embodiment described below and with reference to the Drawings. Showing:

1 shows a two-mass flywheel according to the invention in a partial view with a rolling bearing according to the invention, shown in section a first embodiment,

2 shows a two-mass flywheel according to the invention in a Teilan view with a rolling bearing according to the invention shown in section a second embodiment,

3 shows a two-mass flywheel according to the invention in a partial view with a rolling bearing according to the invention, shown in section, of a third embodiment,

4 shows a two-mass flywheel according to the invention in a partial view with a rolling bearing according to the invention, shown in section a fourth embodiment,

5 shows a two-mass flywheel according to the invention in a partial view with a rolling bearing according to the invention, shown in section a fifth embodiment,

6 shows a two-mass flywheel according to the invention in a partial view with a rolling bearing according to the invention, shown in section a sixth embodiment,

7 shows a two-mass flywheel according to the invention in a partial view with a rolling bearing according to the invention shown in section a seventh embodiment, and

8th shows a two-mass flywheel according to the invention in a partial view with a rolling bearing according to the invention, shown in section an eighth embodiment.

detailed Description of the drawings

1 shows a two-mass flywheel according to the invention 1 consisting of a primary mass 2 that about screws 3 is arranged on the output shaft of an internal combustion engine. About these screws 3 becomes at the same time a cylindrical bearing carrier 4 (Bearing dome) of the primary mass 2 fixed. The bearing carrier is designed with a tight bore tolerance. Also provided is a secondary mass 5 , which attenuated about not shown in detail, curved arranged spiral spring damper with respect to the primary mass 2 is stored. The secondary mass is connected to a clutch, not shown in detail, which is actuated via a not-shown clutch pedal for releasing the power clutch to the transmission, which is also not shown in detail. The structure of such a dual mass flywheel is well known and need not be discussed in detail.

The primary mass 2 and the secondary mass 5 are about a rolling bearing according to the invention 6 a first embodiment rotatably mounted with respect to each other. The rolling bearing 6 has an outer ring 7 as well as an inner ring 8th on, between those in the example shown in the manner of a thrust ball bearing, the rolling elements in the form of balls 9 are guided. The inner ring 8th has a plant section 10 on, to which a storage section 11 followed. The investment section 10 is on the front side 12 of the cylindrical bearing carrier 4 axially counterposed. Radial is the inner ring 8th over the cylindrical bearing section 11 on the outer wall of the bearing carrier 4 established.

The outer ring 7 is U-shaped in cross-section and executed in the manner of a sleeve. To form a large-volume lubricant receiving space 13 extends the outer leg 14 of the outer ring 7 relatively far in the axial direction parallel to the cylindrical bearing carrier 4 , Laterally is a sealing element 15 used in the form of an annular cap-like sealing element, with the outer leg 14 of the outer ring 7 connected is.

On the inner thigh 16 of the outer ring 7 is a plain bearing 17 provided that with the outer ring 7 connected secondary mass 5 with respect to the cylindrical bearing carrier 4 radially stored. The bearings 17 is on the inner thigh 16 pressed.

Of the U-shaped outer ring is preferably made of a thermoformable material, preferably from C45M or C80M with subsequent heat treatment produced. By possibly to be carried out tied hardening and Starting is sufficient diameter and shape accuracy achieved, a post-processing by grinding can be omitted. Also the inner ring may be a corresponding drawn part, as well with the sealing element.

It should already be noted at this point that instead of the sealing element 15 also another sealing element, for example one to the inner ring 8th can be provided slidingly sealing lip, and the corresponding outer diameter of the bearing carrier serves as a sealing career.

2 shows a dual mass flywheel with a rolling bearing according to the invention 18 a second embodiment. Again, on the inner ring 19 an investment section 20 for axial abutment on the end face 21 of the cylindrical bearing carrier 22 , the part of the primary mass 23 is provided. About the storage section 24 the inner ring is radially on the bearing carrier 22 fixed.

The outer ring 25 with which the secondary mass 26 is connected, is here seen cross-section L-shaped. About a here also cap-shaped sealing element 27 the sealing of the lubricant receiving space takes place 28 to one side, wherein between the sealing element 27 and the storage section 24 as well as in the embodiment according to 1 a narrow gap seal is provided. On the other side is a gap seal 29 over the radially inwardly running leg 30 of the outer ring 25 and the inner ring 19 realized.

Again, a plain bearing 31 provided on the cylindrical collar 32 a plain bearing carrier 33 is pressed on. The plain bearing carrier 33 is with the secondary mass 26 connected. The mechanical connection can be realized in any way, for example by riveting, laser soldering or the like.

3 shows a further inventive dual-mass flywheel with egg nem roller bearing according to the invention 34 , This is the inner ring 35 realized as a simple executed hollow cylinder, on the outer wall of a contact section 36 is provided, with which the inner ring 35 at the frontal area 37 of the bearing carrier 38 , the part of the primary mass 39 is axially supported. Also the outer ring 40 is designed as a simple cylinder component. For sealing the large-scale lubricant receiving space 41 is on one side again in the example shown cap-shaped sealing element 42 Pressed, the outer ring 40 is fixed. On the opposite side is another sealing element 43 , here a sealing ring provided with a sliding double lip seal.

In this camp 34 No plain bearing is provided, that is, the bearing 34 takes over both the axial and the radial forces. The radial fixation also takes place here via a corresponding bearing section 44 on the inner ring 35 , which is directly adjacent to the attachment section 36 So join the trained shoulder. Again, the attachment of the outer ring 40 at the secondary mass 45 be any, it can be done directly, for example by laser soldering or the like, but it is also conceivable, a corresponding axially acting and the outer ring on the in 3 Provide right side cross-holding part.

Further it is conceivable, the axial support over a at the secondary mass to provide a molded waistband.

4 shows a two-mass flywheel according to the invention with a rolling bearing 46 a further embodiment of the invention. The inner ring 47 corresponds to the inner ring 35 out 3 , The outer ring 48 is however on both sides with respect to the balls 49 extended section, which offers the possibility, both right and left of the ball row a large-scale lubricant receiving space 50 to build. Left side in 4 is the lubricant receiving space 50 again via a sealing element 51 executed in the form of a sealing cap or the like, in a corresponding manner also takes place on the right side using a sealing cap 52 the sealing of the lubricant receiving space 50 , This bearing thus offers the possibility of realizing a very large volume of lubricant in existing axial space. Also in this embodiment, the rolling element row, as in the previous embodiments, axially located in front of the axial bearing point of the inner ring on the end edge of the bearing support.

5 shows a further embodiment of a dual-mass flywheel with another rolling bearing 53 , Here is the inner ring 54 over the investment section 55 axially and over the bearing section 56 , which is here directly to the plant section 55 connects, radially fixed. The outer ring 57 , as well as the inner ring is a simple drawn part and is designed annular cylindrical, is extended on both sides of the ball guide surfaces, so that here is a very large lubricant receiving space 58 can be realized on both sides of the ball row. Here too are for sealing corresponding sealing elements 59 provided in the form of corresponding sealing caps. The axial fixation of the outer ring 57 and coupling with the secondary mass is carried out here via a secondary exhaust side provided snap ring 60 ,

6 shows a further embodiment according to the invention of a dual mass flywheel with a rolling bearing according to the invention 61 a sixth embodiment. The rolling bearing 61 has an inner ring 62 up, here a first investment section 63 has, over which the axial bearing on the front side 64 of the bearing carrier 65 he follows. Furthermore, a second contact section 66 provided, via which the inner ring to a second radial abutment 67 is axially supported. At this second plant section 66 closes the storage section 67 on, over which the inner ring in addition to the bearing carrier 65 is fixed.

The outer ring 68 the bearing also designed here as an axial thrust bearing is also extended on one side to a lubricant receiving space 69 form, which has a sealing element 70 sealed in the form of a sliding sealing lip. Next is a slide bearing 71 provided, over which the secondary mass, with the outer ring 68 is connected, is mounted radially relative to the primary mass or here of the inner ring. Here, too, a combined rolling-rolling bearing is realized. Opposite is a sealing element 70a ,

7 shows a the rolling bearing 61 out 6 corresponding rolling bearing 72 in which the inner ring 73 in its embodiment, the inner ring 62 out 6 equivalent. On the outer ring 74 leading to the formation of a lubricant receiving space 75 is also extended, here is a plain bearing 76 pressed. The sealing of the lubricant receiving space 75 takes place here via a cap-shaped sealing element 77 , On the other side is a gap seal 78 between the here radially inwardly led collar 79 of the outer ring 74 and the investment section 80 of the inner ring 73 over which these at the face 81 of the bearing carrier 82 is counteracted, realized.

Finally shows 8th a further embodiment of a dual mass flywheel with a rolling bearing according to the invention 83 , The inner ring 84 here too has a first contact section 85 that is at the frontal area 86 of the bearing carrier 87 is opposed, and a second investment section 88 at another abutment edge 89 of the bearing carrier 87 is up against, on. About the intermediate bearing portion of the inner ring is radially fixed. The outer ring 90 completely engages over the inner ring and forms with it a lubricant receiving space 91 that has a sealing cap 92 is sealed. In the bore of the secondary mass is also a plain bearing 93 Pressed in, this directly to the bearing carrier 87 stored up. On the opposite side is the lubricant receiving space 91 also here about a sealing cap 92 sealed.

The illustrated embodiments are not limiting. Of course, instead of a single row ball bearing conceivable, if it gives the space, a double-row angular contact ball bearings, for example to be provided in X arrangement. Also, the respective illustrated are sealing Elements of course variable, a sealing cap can easily against, for example a sealing lip to be replaced or in one piece on z. B. outer ring to be vulcanized.

All in all are the invention shown Rolling bearings extremely simple designed and enabled the use of simple materials or is the production the bearing-forming elements simple and inexpensive. You can as described readily prepared by deep drawing or extrusion or the like become. The space in existing dual-mass flywheels can be optimally utilized, the bearing in the greatest possible distance from the heat-generating friction linings the clutch can be arranged. At the endangered cross sections result low voltages, equally high load capacity combined with a very long life also in conjunction with the spacious designed Lubricant receiving space realized. To improve the thermal insulation it is still conceivable, the respective outer ring with a heat-insulating Layer, which is in the form of plastic rings or caps, that can orbit him, be realized or sprayed on Insulation material.

1

Dual Mass Flywheel

2

primary mass

3

screw

4

bearing bracket

5

secondary mass

6

roller bearing

7

outer ring

8th

inner ring

9

roll

10

contact section

11

bearing section

12

front

13

Lubricant receiving space

14

leg

15

sealing element

16

inner thighs

17

bearings

18

roller bearing

19

inner ring

20

contact section

21

face

22

bearing bracket

23

primary mass

24

bearing section

25

outer ring

26

secondary mass

27

sealing element

28

Lubricant receiving space

29

gap seals

30

leg

31

bearings

32

Federation

33

plain bearing

34

roller bearing

35

inner ring

36

contact section

37

face

38

bearing bracket

39

primary mass

40

outer ring

41

Lubricant receiving space

42

sealing element

43

sealing element

44

bearing section

45

secondary mass

46

roller bearing

47

inner ring

48

outer ring

49

roll

50

Lubricant receiving space

51

sealing element

52

sealing cap

53

roller bearing

54

inner ring

55

contact section

56

bearing section

57

outer ring

58

Lubricant receiving space

59

sealing element

60

snap ring

61

roller bearing

62

inner ring

63

contact section

64

front

65

bearing bracket

66

contact section

67

thrust bearing

68

outer ring

69

Lubricant receiving space

70

sealing element

70a

sealing element

71

bearings

72

roller bearing

73

inner ring

74

outer ring

75

Lubricant receiving space

76

bearings

77

sealing element

78

gap seals

79

Federation

80

contact section

81

face

82

bearing bracket

83

roller bearing

84

inner ring

85

contact section

86

face

87

bearing bracket

88

contact section

89

Abutment edge

90

outer ring

91

Lubricant receiving space

92

sealing cap

93

bearings

Claims (13)

Dual mass flywheel for a motor vehicle, having a primary mass and a secondary mass, which are rotatably connected to each other via at least one rolling bearing with an inner ring and an outer ring, between which rolling elements are guided, characterized in that on a cylindrical bearing carrier ( 4 . 22 . 36 . 65 . 82 . 87 ) of the primary mass ( 2 . 23 . 39 ) rotatably mounted inner ring ( 8th . 19 . 35 . 47 . 54 . 62 . 73 . 84 ) for absorbing axial forces on the front side ( 12 . 21 . 37 . 64 . 81 . 86 ) of the cylindrical bearing carrier ( 4 . 22 . 36 . 65 . 82 . 87 ), and the rolling bearing at least partially axially along the bearing carrier ( 4 . 22 . 36 . 65 . 82 . 87 ) extending, sealed lubricant receiving space ( 13 . 28 . 41 . 50 . 58 . 69 . 75 . 91 ) having. Dual-mass flywheel according to claim 1, characterized in that the rolling bodies ( 9 ) seen in the axial direction in front of the abutting end face ( 12 . 21 . 37 . 86 ) or seen in the radial direction above the abutting end face ( 64 . 81 ) lie. Dual-mass flywheel according to claim 1 or 2, characterized in that the rolling bearing with a plain bearing ( 17 . 31 . 71 . 76 . 93 ) is combined. Rolling bearing for a dual-mass flywheel according to one of the preceding claims, comprising an inner ring, an outer ring and between these guided rolling bodies, characterized in that on nenring in ( 8th . 19 . 35 . 47 . 54 . 62 . 73 . 84 ) a plant section ( 10 . 20 . 36 . 55 . 63 . 80 . 85 ) is formed, with which the inner ring ( 8th . 19 . 35 . 47 . 54 . 62 . 73 . 84 ) axially on an abutment ( 12 . 21 . 37 . 64 . 81 . 86 ) can be defined that a cylindrical, axially extending bearing portion ( 11 . 24 . 44 . 47 . 56 . 67 ) is provided, over which the rolling bearing a cylindrical bearing carrier ( 4 . 22 . 36 . 65 . 82 . 87 ) is fixable, and that the rolling bearing ( 9 ) at least partially axially along the bearing carrier ( 4 . 22 . 36 . 65 . 82 . 87 ) extending, sealed lubricant receiving space ( 13 . 28 . 41 . 50 . 58 . 69 . 75 . 91 ) having. Rolling bearing according to claim 4, characterized in that the rolling bodies ( 9 ) seen axially in front of the contact section ( 10 . 20 . 36 . 55 . 85 ) or radially above the abutment section (FIG. 63 . 80 ) lie. Rolling bearing according to claim 4 or 5, characterized in that the outer ring ( 7 . 25 . 40 . 48 . 57 . 68 . 74 . 90 ) in the axial direction on one or both sides of a rolling element ( 9 ) leading portion and together with the one or both sides axially elongated inner ring ( 8th . 19 . 35 . 47 . 54 . 62 . 73 . 84 ) and / or at least one, preferably annular and cap-like, sealing element ( 15 . 27 . 42 . 43 . 51 . 52 . 59 . 70 . 70a . 77 . 92 ) a lubricant receiving space ( 13 . 28 . 41 . 50 . 58 . 69 . 75 . 91 ). Rolling bearing according to claim 6, characterized in that aside a, preferably annular and cap-like, sealing element ( 42 . 43 . 51 . 52 . 59 . 70 . 70a ) is provided. Rolling bearing according to one of the preceding claims, characterized in that characterized in that the axial bearing section ( 11 . 24 . 44 . 56 ) to the abutment section ( 10 . 20 . 36 . 55 ). Rolling bearing according to one of claims 4 to 8, characterized in that it is provided with a plain bearing ( 17 . 31 . 71 . 76 . 93 ) is combined. Rolling bearing according to claim 9, characterized in that the outer ring ( 7 . 25 ) is executed in cross-section substantially U-shaped and sleeve-like and at its radially inner leg ( 16 ) the sliding bearing ( 17 . 31 ) is provided. Rolling bearing according to claim 9, characterized in that the plain bearing ( 71 . 76 . 93 ) on the outer ring ( 68 . 74 . 90 ) is provided and - in the mounting position - supports radially inwardly to the outer wall of the cylindrical bearing portion or the inner ring out. Rolling bearing according to one of the preceding claims, characterized in that on the outer diameter of the outer ring ( 7 . 25 . 40 . 48 . 57 . 68 . 74 . 90 ) is arranged for thermal insulation, a plastic sleeve, or that the outer ring ( 7 . 25 . 40 . 48 . 57 . 68 . 74 . 90 ) is coated with a heat-insulating layer. Rolling bearing according to one of the preceding claims, characterized in that at least the cylindrical diameter of the inner ring ( 8th . 19 . 35 . 47 . 54 . 62 . 73 . 84 ), which in contact with the cylindrical diameter of the bearing carrier ( 4 . 22 . 36 . 65 . 82 . 87 ) is coated with a hard chromium layer, a nickel layer or a lubricating varnish layer to prevent tribo-corrosion.