DE102018131102A1 - Vibration damping method in a motor vehicle transmission - Google Patents

Abstract

The invention relates to a method for damping vibrations of acoustic vibrations in a motor vehicle transmission (1) with at least one transmission component (3, 4, 27, 28, 29) rotatably mounted in a transmission housing (2), the rotatably supported transmission component (3, 4, 27, 28, 29) is rotatably supported by means of a hybrid bearing (10) with a roller bearing (11) and a slide bearing (12). The roller bearing (11) and the slide bearing (12) of the hybrid bearing (10) are arranged parallel to one another. The hybrid bearing (10) has a first bearing ring (13) and a second bearing ring (14), between which a plurality of rolling elements (15) are arranged, with a sliding body (23) on at least one of the bearing rings (13, 14) Plain bearing (12) is formed. In a first operating state, the rotatably mounted gear component (3, 4, 27, 28, 29) rotates at a first rotational speed below a critical resonance speed, at which the rotatably mounted gear component (3, 4, 27, 28, 29) essentially through the Rolling bearing (11) is worn. In a second operating state with a second speed above the first speed, the rotatably mounted gear component (3, 4, 27, 28, 29) is at least partially carried by the slide bearing (12), with the lubricating film in the slide bearing (12) transmitting the The invention further relates to a motor vehicle transmission (1), in particular an axle transmission, with such a hybrid bearing (10).

Description

The invention relates to a method for vibration damping in a motor vehicle transmission and a motor vehicle transmission with a hybrid bearing for vibration damping according to the preamble of the independent claims.

Periodic excitation mechanisms can cause noise in machines. These noises lead to direct and indirect noises in the form of airborne noise. With the direct transmission path, the excitation source immediately causes fluctuations in air pressure, which can spread in the form of airborne sound. For the noise behavior of machines, however, the indirect transmission path is decisive for the noise behavior. In this indirect vibration transmission, a time-varying operating force is introduced into a machine structure, where it is transmitted to the surface in the form of structure-borne noise and is emitted from there to the environment as airborne noise. A simple structure-borne noise transmission chain, which is also referred to as a transfer path, comprises a drive shaft, a bearing on which the drive shaft is rotatably mounted and a machine housing to which the structure-borne noise is transmitted and from there is emitted as airborne sound. The natural frequencies of the components in the structure-borne sound transmission chain can increase the noise. Such noises occur, for example, in motor vehicle transmissions, the structure-borne sound waves being produced by the toothing of two gearwheels rolling on one another under load and being transmitted to the transmission housing via the bearings of the transmission shafts. Due to the forces and moments that occur when the gear wheels roll, vibrations occur which are perceived by a machine user, in particular by the occupants of the motor vehicle, as gear rattles or gear whine. In addition, noises can also occur at other points in the transmission, for example when the rolling elements roll in the rolling bearings. These noises generated in the transmission are transmitted as structure-borne noise via gearwheels, transmission shafts and bearings to the transmission housing and from there are emitted to the environment as airborne sound or are transmitted to the machine structure in the form of structure-borne noise.

In order to reduce the noise development in a transmission, measures can be taken to minimize the vibration excitations, which are referred to as primary measures. Secondary measures can also be taken to reduce the transmission of structure-borne sound waves to the transmission housing or to radiate sound waves from the transmission housing of the transmission. The primary measures include, for example, optimizing the stiffness profile of the tooth flanks and reducing the deviations between the tooth flanks. However, as a rule, these lead to a significant increase in manufacturing costs, since these measures are associated with lower manufacturing tolerances and the associated higher processing times for the components. In addition, these measures cannot contribute to noise minimization in all load cases, so that these primary measures are generally not suitable as sole measures for noise reduction.

The secondary measures that are intended to minimize the transmission of sound waves to the housing and the radiation of the sound waves include various types of insulation and damping measures as well as measures that aim to change the natural vibration behavior of the components that are significantly involved in structure-borne sound development and structure-borne sound conduction. One possibility for noise reduction is to acoustically isolate the bearing points of the transmission shafts from the transmission housing and thus to minimize vibration transmission via the bearing points. However, such decoupling and damping measures bring about a significant reduction in the rigidity for connecting the elastically mounted gear components to the gear housing. By reducing the rigidity at the connection points, there is an increased displacement of the transmission components relative to one another when torque is transmitted. This can lead to an increased load on the tooth flanks of meshing gear wheels and an associated increased wear of the gear components. In addition, the elastic mounting can lead to increased vibration excitation and, as a result, to increased noise. The fact that only isolated transmission components can be isolated can also have a disadvantage. Due to the reduced rigidity at the isolated connection points, the forces arising from the power transmission are increasingly supported at the other connection points. Thus, a large part of the structure-borne sound waves are diverted, so that a strong vibration excitation of the gear housing and an associated noise pollution continue to occur.

From the DE 10 2014 118 553 A1 a rolling bearing with an inner ring and an outer ring is known, a large number of rolling elements being arranged between the inner ring and the outer ring. The outer ring is divided by a damping layer consisting of a vibration-damping material, which is integrated into the outer ring in such a way that the outer ring is covered by the Damping layer is divided into two independent parts.

The DE 10 2005 032 283 B3 discloses a hybrid bearing with a roller bearing and a slide bearing arranged parallel to the roller bearing, the roller bearing having an outer ring and an inner ring, between which a plurality of roller bodies is arranged. The outer ring and the inner ring are dimensioned such that a lubrication gap is formed between them. The roller bearing and the plain bearing are arranged axially adjacent on the same axis of rotation.

The object of the invention is to minimize the noise in a machine, in particular in a motor vehicle transmission, and to overcome the disadvantages known from the prior art.

According to the invention, this object is achieved by a method for damping vibrations of acoustic vibrations in a motor vehicle transmission with at least one transmission component rotatably mounted in a transmission housing, the rotatably mounted transmission component being rotatably supported by means of a hybrid bearing with a roller bearing and a slide bearing, the roller bearing and the slide bearing of the hybrid bearing are arranged parallel to one another, the hybrid bearing having a first bearing ring and a second bearing ring, between which a plurality of rolling elements are arranged, and wherein a sliding body of the sliding bearing is formed on at least one of the bearing rings. It is provided that the rotatably mounted gear component rotates in a first operating state at a first speed below a critical resonance speed, at which the gear component is essentially carried by the roller bearing. Furthermore, it is provided that the rotatably mounted gear component is at least partially carried by the slide bearing in a second operating state at a second speed above the first speed, the transmission of the acoustic vibrations being damped by the lubricating film in the slide bearing. At standstill and at low speeds, the roller bearing takes over the bearing function of the rotating gear component. As the speed increases, a lubricating film forms in the plain bearing. The load between the plain bearing and the roller bearing is thus divided by the pressure that arises. The roller bearing is relieved, which reduces the transmission of structure-borne noise. In addition, the lubricant in the plain bearing has a dampening effect on the transmitted structure-borne noise. If a lubricating film with an appropriate oil pressure is built up, the oil in the lubricating gap of the plain bearing has a vibration-damping effect. In addition, the ball bearing of the hybrid bearing does not have to be designed for maximum loads, since the forces are transmitted via the plain bearing at high speeds. In addition, the lubricant of the plain bearing can be used to supply the roller bearing with lubricant, which improves the lubricant supply to the roller bearing.

The features listed in the dependent claims enable advantageous improvements and developments of the method for vibration damping proposed in the independent claim in a motor vehicle transmission.

In an advantageous embodiment of the invention it is provided that the rotatably mounted gear component is a gear shaft. The bearing points of the transmission shafts are generally heavily loaded by the forces and moments to be transmitted, structure-borne noise being transmitted from the transmission shaft to the transmission housing at these bearing points. This structure-borne noise transmission can be weakened by a corresponding hybrid bearing and the acoustic behavior of the motor vehicle transmission can thus be improved.

Alternatively, it is advantageously provided that the motor vehicle transmission is designed as a planetary transmission, the rotatably mounted transmission component being a planet carrier, a ring gear or a hollow shaft connected to the planet carrier or to the ring gear. In the case of a planetary gear, in addition to the gear shafts, the planet carrier, the ring gear or a hollow shaft, which is connected to the planet carrier or the ring gear in a rotationally fixed manner, can also be rotatably mounted in the gear housing of the motor vehicle transmission. Corresponding structure-borne noise transmission is also possible via these components, so that a hybrid bearing can also be used for storage here in order to improve the acoustic behavior of the motor vehicle transmission.

In a preferred embodiment of the hybrid bearing it is provided that the sliding body, in particular a sliding bearing shell, is connected to the first bearing ring, in particular the outer ring of the hybrid bearing, with a between the sliding body and the second bearing ring Gap is formed in which a stable lubricating film is formed at the second speed. The gap prevents direct structure-borne noise transmission via the plain bearing at low speeds. In addition, the gap favors the formation of a load-bearing lubricating film, as a result of which the lubricant supply to the plain bearing can be improved.

Alternatively, it is advantageously provided that the sliding body, in particular a sliding bearing shell, is connected to the second bearing ring, a gap being formed between the sliding body and the first bearing ring, in which a stable lubricating film is formed at the second speed. Alternatively, the sliding body can also be arranged on the second bearing ring, in particular on the inner ring of the hybrid bearing, in order to minimize the friction in the sliding bearing. A gap has the same positive effects as if the sliding body were arranged on the first bearing ring. Alternatively, sliding bodies or sliding coatings can also be provided on both bearing rings in order to minimize the friction in the sliding bearing as long as the speed is still so low that the lubricating film fully supports the rotating machine component and the sliding bearing is operated in the area of mixed friction.

In a preferred embodiment of the invention it is provided that a rolling element raceway is formed on at least one of the bearing rings, preferably on both bearing rings. Rolling element raceways on the bearing rings allow simple and reliable guidance of the rolling elements in the respective bearing rings. Alternatively or additionally, the rolling elements can be guided over a bearing cage in order to define the distance between the rolling elements and to further improve the positioning. This is particularly advantageous if the roller bearing is fluidly connected to the slide bearing and is acted upon by the lubricant pressure.

In a further preferred embodiment of the hybrid bearing, it is provided that a sealing element is provided between the slide bearing and the roller bearing. A sealing element, in particular a sealing gap, can prevent the rolling bearing from being subjected to high lubricant pressure, so that additional transverse forces caused by the lubricant can be avoided. The rolling bearing is advantageously lubricated by the lubricant of the sliding bearing, as a result of which the rolling elements are adequately lubricated over the lifetime of the hybrid bearing. Alternatively, the roller bearing and the plain bearing can also be lubricated with different lubricants. This requires an adequate seal between the roller bearing and the plain bearing.

According to an advantageous improvement of the invention, it is provided that at least one of the bearing rings is provided with a supply bore with which a lubricant is applied to the plain bearing. A supply hole makes it possible to apply a lubricant, in particular an oil, to the plain bearing in a simple and reliable manner. A lubricant pump is provided, which supplies the hybrid bearing with a sufficient amount of lubricant and a sufficient lubricant pressure. The lubricant supply for the plain bearing can also be deactivated at low speeds in order to minimize friction. Alternatively, the lubricant supply can also be switched on in certain operating situations in order to relieve the roller bearing in certain situations and / or to introduce targeted damping into the hybrid bearing.

To form a lubricating film in the plain bearing, a corresponding lubricant gap is required, which can be structurally introduced into the hybrid bearing. As a result of the introduction of force in the rolling bearing, the bearing play and the bearing rigidity result in a shift which can be used to form this lubricant gap in the plain bearing. In one embodiment of the invention, it is provided that the axes of the slide bearing and the roller bearing are offset from one another in order to use the slide bearing in a targeted manner and thus to introduce a corresponding damping into the hybrid bearing.

According to an advantageous embodiment of the hybrid bearing, it is provided that the rolling bodies are designed as balls, needles or rollers, in particular cylindrical rollers.

According to the invention, a motor vehicle transmission, in particular an axle transmission for a motor vehicle, is proposed with at least one transmission component rotatably mounted in a transmission housing. It is provided that the rotatably mounted gear component is rotatably supported by means of a hybrid bearing with a roller bearing and a plain bearing. The motor vehicle transmission is set up to carry out a vibration damping method according to the invention in order to minimize the transmission of structure-borne noise. In motor vehicles, the transmission noise is often perceived by the vehicle occupants as annoying. Therefore, a transmission with a hybrid bearing is advantageous in particular in applications in a motor vehicle in order to minimize this transmission noise.

Unless otherwise stated in the individual case, the various embodiments of the invention mentioned in this application can advantageously be combined with one another.

• 1 ein erstes Ausführungsbeispiel eines Kraftfahrzeuggetriebes mit einem Hybridlager;
• 2 ein erfindungsgemäßes Hybridlager für ein solches Kraftfahrzeuggetriebe in einer Schnittdarstellung;
• 3 ein weiteres Ausführungsbeispiel für ein erfindungsgemäßes Hybridlager in einer Schnittdarstellung; und
• 4 ein Kraftfahrzeuggetriebe in Form eines Planetengetriebes, bei dem zumindest eines der drehbar in einem Getriebegehäuse lagerbaren Getriebebauteile mittels eines solchen Hybridlagers gelagert ist, um die Übertragung von akustischen Schwingungen zu minimieren.

The invention is explained below on the basis of preferred embodiments with reference to the attached figures. The same components or components with the same function are identified by the same reference numerals. It shows:

• 1 a first embodiment of a motor vehicle transmission with a hybrid bearing;
• 2 a hybrid bearing according to the invention for such a motor vehicle transmission in a sectional view;
• 3 a further embodiment of a hybrid bearing according to the invention in a sectional view; and
• 4 a motor vehicle transmission in the form of a planetary transmission, in which at least one of the transmission components which can be rotatably supported in a transmission housing is supported by means of such a hybrid bearing in order to minimize the transmission of acoustic vibrations.

In 1 is an embodiment of a motor vehicle transmission according to the invention 1 with a hybrid bearing 10 shown. The automotive transmission 1 has a gearbox 2 on in which a drive shaft 3 of the motor vehicle transmission 1 and an output shaft 4 are rotatably mounted. There is at least one of the waves 3 . 4 at at least one storage location 8th . 9 by means of a hybrid bearing according to the invention 10 stored in the gearbox. The drive shaft 3 carries at least one first gear 5 which with a second gear 6 on the output shaft 4 is in operative connection. Thus, a torque M ₁ and a speed n _{1 of} the drive shaft 3 into an adjusted torque M ₂ and an adjusted speed n _{2 of} the output shaft 4 be changed. The automotive transmission 1 can for example be designed as a manual transmission of an internal combustion engine, differential gear or axle ratio.

The hybrid warehouse 10 of the motor vehicle transmission according to the invention 1 is in 2 shown in a sectional view. The hybrid warehouse 10 a plain bearing 12 and a rolling bearing 11 on which are arranged parallel to each other. The hybrid warehouse 10 comprises a first bearing ring 13 , in particular an outer ring, and a second bearing ring 14 , especially an inner ring. In the rolling bearing 11 are between the first bearing ring 13 and the second bearing ring 14 a variety of rolling elements 15 , in particular balls, needles or rollers. The rolling elements 15 are through a first rolling element raceway 16 on the first bearing ring 13 and through a second rolling element raceway 17 on the second bearing ring 14 guided. Furthermore, a cage can be provided which holds the rolling elements 15 of the rolling bearing 11 leads spaced from each other and holds in position.

The plain bearing 23 points to at least one of the bearing rings 13 . 14 a sliding body 23 on which is the friction between the first bearing ring 13 and the second bearing ring 14 minimized. The sliding body 23 is preferably designed as a plain bearing ring, which is the friction between the gear shaft 3 . 4 and the bearing ring 13 . 14 minimized when the hybrid bearing 10 rotates at low speeds and the forces on the rolling bearing 11 and / or the plain bearing 12 be transferred when the plain bearing 12 is operated in the area of mixed friction. The sliding body 23 is with the first bearing ring 13 connected, being between the sliding body 23 and the second bearing ring 14 A gap 19 can be trained. Through the gap 19 friction at low speeds is minimized. In addition, the gap 19 favor the formation of a lubricating film that is in the plain bearing 12 trains and significantly absorbs the bearing forces at high speeds. Alternatively, on the second bearing ring 13 . 14 another plain bearing layer 18 , in particular a further plain bearing shell. Here are the sliding layers 18 . 21 preferably made of a friction-minimizing material, in particular a coating 22 made of a polytetrafluoroethylene, a ceramic coating or a carbon coating. Alternatively, the sliding layer 21 be designed as a slide bearing shell made of a ceramic material or a metallic alloy. For lubricating the plain bearing 12 is in the first bearing ring 13 a supply well 25 provided, via which lubricant in the lubrication gap of the plain bearing 12 can be supplied.

In 3 is another embodiment of a hybrid bearing 10 for a motor vehicle transmission according to the invention 1 shown. With essentially the same structure as for 2 is executed in this embodiment, the sliding body 23 with the second bearing ring 14 connected, being between the sliding body 23 and the first bearing ring 13 A gap 20 is trained. There can also be between the plain bearing 12 and the rolling bearing 11 of the hybrid bearing 10 a sealing element 24 , in particular a sealing gap to be formed in order to reduce the lubricant pressure. Thus, the transverse forces acting on the rolling elements can be reduced, with which the rolling elements 15 of the rolling bearing 11 are acted upon. The hybrid bearing can also be sealed 10 be simplified if the rolling elements 15 be operated in a lubricant environment with comparatively low pressure.

In an idle state and at low speeds of the hybrid bearing 10 is the bearing function by the rolling bearing 11 accepted. With increasing speed, forms in the plain bearing 12 a lubricating film. Thus, the load between the rolling bearing 11 and the plain bearing 12 divided by the resulting lubricant film. In addition, the lubricant film in the plain bearing has a dampening effect on the transmitted structure-borne sound waves. By relieving the roller bearing 11 this effect is intensified. At high speeds, the bearing function can essentially be due to the plain bearing 12 accepted be causing the rolling bearing 11 is relieved and the transmission chain for the structure-borne noise transmission is interrupted.

In 4 is a motor vehicle transmission 1 in the form of a planetary gear 26 shown. The planetary gear 26 includes a sun wave 3 holding a sun gear 30 wearing. The sun gear 30 stands with several planet gears 31 engaged, which on a planet carrier 27 are arranged. The planet carrier 27 is with an output shaft 4 non-rotatably connected. The planet gears 31 are in a ring gear 28 arranged, a toothing of the planet gears 31 with a toothing of the ring gear 28 is engaged. The ring gear 28 is non-rotatable with a hollow shaft 29 connected which is the output shaft 4 jacketed. Here is at least one of the rotatably mounted gear elements 3 . 4 . 27 . 28 . 29 with a hybrid bearing 10 stored to reduce the structure-borne noise and thus the noise of the motor vehicle transmission 1 to minimize.

LIST OF REFERENCE NUMBERS

1

Motor vehicle transmission

2

gearbox

3

drive shaft

4

output shaft

5

First gear

6

Second gear

7

differential gear

8th

First depository

9

Second depository

10

hybrid bearings

11

roller bearing

12

bearings

13

First bearing ring

14

Second bearing ring

15

rolling elements

16

First rolling element race

17

Second rolling element raceway

18

plain bearing layer

19

gap

20

gap

21

Overlay

22

coating

23

sliding

24

sealing element

25

supply hole

26

planetary gear

27

planet carrier

28

ring gear

29

hollow shaft

30

sun

31

planet

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

• DE 102014118553 A1 [0005]
• DE 102005032283 B3 [0006]

Claims (10)

Method for damping vibrations of acoustic vibrations in a motor vehicle transmission (1) with at least one transmission component (3, 4, 27, 28, 29) rotatably mounted in a transmission housing (2), the rotatably mounted transmission component (3, 4, 27, 28, 29) is rotatably mounted by means of a hybrid bearing (10) with a roller bearing (11) and a slide bearing (12), the roller bearing (11) and the slide bearing (12) of the hybrid bearing (10) being arranged parallel to one another, the hybrid bearing ( 10) has a first bearing ring (13) and a second bearing ring (14), between which a plurality of rolling bodies (15) are arranged, a sliding body (23) of the sliding bearing (12) being arranged on at least one of the bearing rings (13, 14) The rotatably mounted gear component (3, 4, 27, 28, 29) rotates in a first operating state at a first speed below a critical resonance speed, at which the rotatably mounted gear component (3, 4, 27, 28, 29) essentially carried by the roller bearing (11), and in a second operating state at a second speed above the first speed of the rotatably mounted gear component (3, 4, 27, 28, 29) is at least partially carried by the slide bearing (12) A transmission of the acoustic vibrations is damped by the lubricating film in the slide bearing (12). Vibration damping method according to Claim 1 , characterized in that the rotatably mounted gear component (3, 4, 27, 28, 29) is a gear shaft (3, 4). Vibration damping method according to Claim 1 , characterized in that the motor vehicle transmission (1) is designed as a planetary gear (26), the rotatably mounted gear component (3, 4, 27, 28, 29) being a planet carrier (27), a ring gear (28) or one with the Planet carrier (27) or with the ring gear (28) connected hollow shaft (29). Vibration damping method according to one of the Claims 1 to 3 , characterized in that the sliding body (23) is connected to the first bearing ring (13), a gap (19) being formed between the sliding body (23) and the second bearing ring (14), in which a gap occurs at the second speed viable lubricant film. Vibration damping method according to Claim 1 to 3 , characterized in that the sliding body (23) is connected to the second bearing ring (14), a gap (20) being formed between the sliding body (23) and the first bearing ring (13), in which a gap occurs at the second speed viable lubricant film. Vibration damping method according to one of the Claims 1 to 5 , characterized in that a rolling element raceway (16, 17) is formed on at least one of the bearing rings (13, 14), the rolling elements (15) being guided in the rolling element raceway (16, 17). Vibration damping method according to one of the Claims 1 to 6 , characterized in that a supply bore (25) is formed on at least one of the bearing rings (13, 14) with which a lubricant is applied to the sliding bearing (12). Vibration damping method according to one of the Claims 1 to 7 , characterized in that the axes of the plain bearing (12) and the roller bearing (11) are offset from one another. Method of damping shrinkage according to one of the Claims 1 to 8th , characterized in that the rolling elements (15) are designed as balls, needles or rollers, the contact pressure of the rolling elements (15) on at least one of the bearing rings (13, 14) of the rolling bearing (11) due to the load-bearing lubricating gap in the sliding bearing ( 12) is reduced. Motor vehicle transmission (1) with at least one transmission component shaft (3, 4, 27, 28, 29) rotatably mounted in a transmission housing (2), the rotatably mounted transmission component (3, 4, 27, 28, 29) by means of a hybrid bearing (10) with a roller bearing (11) and a slide bearing (12) is rotatably mounted, the motor vehicle transmission (1) being set up to implement a method according to one of the Claims 1 to 9 to carry out in order to reduce the transmission noise of the motor vehicle transmission (1).

Images