CN110953325A

CN110953325A - Motor vehicle speed variator

Info

Publication number: CN110953325A
Application number: CN201910911698.5A
Authority: CN
Inventors: 托尼·泽伊斯
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Technologies AG and Co KG
Priority date: 2018-09-27
Filing date: 2019-09-25
Publication date: 2020-04-03
Anticipated expiration: 2039-09-25
Also published as: CN110953325B; DE102018123870A1

Abstract

The invention relates to a motor vehicle transmission (1) having a transmission housing (8) and a mechanism for converting a first rotational movement into a second rotational movement with a different rotational speed and/or a different rotational direction, wherein the motor vehicle transmission (1) comprises a first transmission shaft (2) and a second transmission shaft (3) which are rotatably mounted in the transmission housing (8) by means of rolling bearings (6, 7, 15, 16), wherein the first transmission shaft (2) carries a first gearwheel (4) and the second transmission shaft (3) carries a second gearwheel (5) which is or can be engaged with the first gearwheel. It proposes: the motor vehicle transmission has a carrier plate (9) which comprises at least two bearing points for supporting the transmission shafts (2, 3), wherein a plurality of slits (27) are introduced into the carrier plate (9) in order to reduce the rigidity of the carrier plate (9) in a sub-region of the carrier plate (9).

Description

Motor vehicle speed variator

Technical Field

The invention relates to a motor vehicle transmission having a carrier plate and to a method for producing such a carrier plate.

Background

In motor vehicle transmissions, internal vibration excitations lead to system-dependent noise development. The main source of noise is the tooth flanks of the engaged gears that roll under load, since the forces and moments occurring during rolling result in vibration excitations that are perceived by the occupants of the motor vehicle as transmission rattles or transmission rattles. Furthermore, noise can also be generated at other locations of the motor vehicle transmission, for example by rolling noise of the rolling bearing. The noise generated in the motor vehicle transmission is transmitted as structure-borne noise via the gear wheels, the transmission shaft and the bearings to the transmission housing and from there is emitted as airborne sound into the environment or introduced in the form of structure-borne noise into the vehicle structure. A typical component in the transmission chain is a transmission bearing, which is located in direct force flow with the transmission housing.

In order to reduce the development of noise in motor vehicle transmissions, measures can be taken in order to minimize the excitation of vibrations, which are referred to as primary measures. In addition, countermeasures can be taken in order to reduce the transmission of sound waves to the transmission housing or to reduce the emission of sound waves from the transmission housing of the motor vehicle transmission. For example, optimization of the stiffness profile of the tooth flanks and reduction of the deviations between the tooth flanks are the main measures. However, this generally leads to a considerable increase in production costs, since said measures are accompanied by lower manufacturing tolerances and higher processing times of the components associated therewith. Furthermore, these measures cannot contribute to noise minimization in all load situations, so that the main measure is generally not suitable as the only measure for noise reduction.

The secondary measures include different types of isolation and damping measures and measures which are intended to change the natural vibration behavior of the components typically involved in structure-borne sound development and structure-borne sound guidance, wherein the transmission of sound waves and the emission of sound waves to the housing are minimized by means of the secondary measures. The possibility of noise reduction lies in the isolation of the bearing points from the transmission housing.

DE 19502560 a1 discloses a motor vehicle transmission in which at least two gearwheels are provided that are rotatable relative to one another, said gearwheels being in engagement with one another. The gear wheels are mounted on at least one end of a common carrier plate, wherein an elastic spring ring made of a polymer material is provided between the carrier plate and the transmission housing in order to reduce the sound introduction into the transmission housing.

A bearing carrier is known from DE 202017104746U 1, which carries a first outer ring and a second outer ring of two rolling bearings. The outer rings of the rolling bearing each have a groove which extends completely in the circumferential direction around the respective outer ring. Furthermore, the bearing carrier comprises a basic body, into which the outer ring of the rolling bearing is embedded. A flexible coupling element is provided between the outer ring and the basic body in order to reduce the transmission of vibrations from the outer ring to the bearing support.

DE 102007006228 a1 discloses a transmission having a housing in which at least two shafts for setting a desired transmission ratio can be coupled to one another via a gear train, wherein the shafts are rotatably mounted in the housing by means of a carrier plate. The support plate is supported on the housing via at least one damping element for damping sound and vibrations. The shifting device for adjusting the transmission is fixed to at least one of the support plates decoupled from the housing.

Another possibility of noise reduction is to isolate the individual bearing points of the transmission shaft from the transmission housing. This measure however causes a significant reduction in the bearing stiffness in the radial direction. The shaft is moved when transmitting the torque in the transmission by reducing the stiffness at the bearing point. This significantly influences the surface contact pressure profile of the teeth in the spur gear transmission. This may result in minimization of durability and result in higher excitation; thereby increasing noise formation. Another disadvantage arises when only individual support points can be isolated. By the reduced rigidity of the isolated bearing points in relation to the non-isolated bearing points, forces and moments are supported in a strengthened manner on the non-isolated bearing points, as a result of which the load on these bearing points is increased and the structure-borne sound transmission on these bearing points is strengthened.

Disclosure of Invention

The object of the invention is to minimize the development of noise 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 motor vehicle transmission having a transmission housing and a mechanism for converting a first rotary motion into a second rotary motion with a different rotational speed and/or a different rotational direction, wherein the motor vehicle transmission comprises a first transmission shaft and a second transmission shaft which are rotatably mounted in the transmission housing by means of a rolling bearing, wherein the first transmission shaft carries a first gearwheel and the second transmission shaft carries a second gearwheel which is or can be engaged with the first gearwheel. It proposes: the motor vehicle transmission has a carrier plate which comprises at least two bearing points for bearing a transmission shaft, wherein a plurality of slits are introduced into the carrier plate in order to reduce the rigidity of the carrier plate in a subregion of the carrier plate. By means of said slits in said support plate the stiffness of the support plate and thus the range of the natural frequency can be varied. Furthermore, the slits lead to damping of vibrations, thereby reducing the transmission of solid sound waves from the transmission shaft to the transmission housing.

The features listed below make possible the advantageous improvements and developments of the motor vehicle transmission set forth below.

In a preferred embodiment of the motor vehicle transmission, it is provided that: the bearing plate has a first opening and a second opening, wherein a rolling bearing for supporting a transmission shaft is arranged in the opening of the bearing plate. Coupling of the transmission shafts is thereby possible, whereby the rigidity of the transmission composite is increased and the deflection of the transmission shafts is reduced. This reduces the bearing load on the rolling bearing, and thus reduces the transmission of vibrations to the transmission housing. Furthermore, additional damping elements can be provided by means of the small deflection of the transmission shaft, by means of which the transmission of vibrations from the rolling bearing to the carrier plate and/or from the carrier plate to the transmission housing is reduced.

In a preferred embodiment of the invention, it is provided that the slits are arranged circularly around a respective opening in the support plate. For many applications it has proven advantageous to introduce the slits into the support plate such that a circular shape is formed around the respective opening in the support plate. The transmission of structure-borne sound from the rolling bearing accommodated in the opening to the transmission housing is thereby minimized.

For other application cases, it is advantageously proposed: the slit has a meandering shape. In this case, the slits are introduced at corresponding points of the support plate in order to achieve a local reduction in the stiffness.

In an advantageous further development: the support plate is composed of a plurality of plate materials. The support plate, which is composed of a plurality of metal sheets, additionally produces a slot between the individual metal sheets, which also act in a vibration-damped manner. Furthermore, the production is simplified, since the individual sheet metal parts can be produced simply and inexpensively as stamped parts. Furthermore, the designer gains another degree of freedom in designing the support plate, since the slits do not have to pass completely through the entire support plate, but can only be present in the individual sheet material. The support plate can thus be better tuned with respect to the vibrations to be damped.

In a preferred embodiment of the motor vehicle transmission, it is provided that: at least two fastening openings are provided on the carrier plate, via which the carrier plate can be fastened to a further transmission component. Simple fastening of the support plate is achieved by the fastening opening. In this case, additional damping elements can be provided at the fastening openings in order to reduce the transmission of solid acoustic waves. The support plate can be fixed not only directly to the transmission housing but also to another transmission component. Here, sufficient damping is achieved by the slits in the carrier plate, so that transmission noise is minimized.

According to an advantageous embodiment of the invention, it is provided that: the first transmission shaft and the second transmission shaft are supported in the transmission housing at a first bearing point and a second bearing point, respectively, wherein the bearing plate forms at least one of the bearing points. Since the installation space in motor vehicle transmissions is usually narrow and at the same time there is as little weight effort as possible toward the motor vehicle transmission, a carrier plate is used in such motor vehicle transmissions, which carrier plate makes it possible to support the second transmission shaft in a compact and space-saving manner. Since such bearing plates can be excited by the vibration of the two transmission shafts, according to the principle, they are particularly critical with regard to the transmission of structure-borne sound from the transmission shafts to the transmission housing. A corresponding vibration damping can be achieved by the slits in the carrier plate, so that structure-borne noise is transmitted to the transmission housing only to a very limited extent.

Alternatively, a further embodiment of the invention provides for: the first transmission shaft and the second transmission shaft are each supported in the transmission housing at a first bearing point and a second bearing point, wherein the bearing plate is a coupling plate which forms an additional bearing point between the first bearing point and the second bearing point. The additional bearing points reduce the deflection of the transmission shaft, in particular in the case of transmissions having long transmission shafts and a plurality of gear pairs. As a result, the load at the bearing point can be reduced overall, thereby minimizing the structure-borne noise as a whole. Although the coupling plate forms a further transmission path for the structure-borne noise, if the coupling plate is in direct contact with the transmission housing, the transmission noise is reduced overall by a corresponding damping by the slits in the coupling plate and a small deflection of the transmission shaft and the bearing forces thus reduced.

According to the invention, a carrier plate for a motor vehicle transmission is proposed, wherein a plurality of slits are introduced into the carrier plate in order to reduce the rigidity of the carrier plate in a subregion of the carrier plate. By using such a bearing plate for supporting the transmission shaft in the motor vehicle transmission, the transmission of vibrations from the bearing of the transmission shaft to the transmission housing is reduced, whereby transmission noise can be minimized.

In an advantageous embodiment of the invention, it is provided that: the slits in the support plate are filled with a vibration-damping filling material, in particular a plastic or foam material. The damping effect of the slit can be intensified by a correspondingly highly damping filler material.

Furthermore, according to the invention, a method for producing a carrier plate of a motor vehicle transmission is proposed, wherein slits for locally reducing the rigidity of the carrier plate are introduced into the carrier plate. By introducing said slits, the support plate can be adjusted according to the vibrations occurring in order to minimize the transmission of solid acoustic waves.

In a preferred embodiment of the method, it is provided that: the support plate consists of a plurality of sheet metal parts, wherein the slits are preferably introduced into the sheet metal parts by means of a punching method or a precision cutting method. The individual metal sheets can be produced in a correspondingly thin manner by the support plate consisting of metal sheets stacked on top of one another, whereby the introduction of the slits by means of a punching method or a precision cutting method can be achieved at correspondingly low cost and with relatively low tool expenditure.

Furthermore, the individual sheet metal parts can be clamped to one another by means of suitable clamping mechanisms, as a result of which the sheet metal parts are elastically and/or plastically deformed. Thereby, the natural frequency of the support plate can be changed, thereby optimizing the damping characteristics of the support plate.

The different embodiments of the invention mentioned in the present application can advantageously be combined with one another as long as they are not explained otherwise in individual cases.

Drawings

The invention is elucidated below in accordance with a preferred embodiment with reference to the accompanying drawings. Identical components or components having identical functions are denoted by the same reference numerals here. The figures show:

fig. 1 shows an exemplary embodiment of a motor vehicle transmission according to the invention with two transmission shafts, wherein the transmission shafts are rotatably mounted in a transmission housing at least at one bearing point by means of a bearing plate;

FIG. 2 shows an embodiment of a support plate of a motor vehicle transmission according to the present invention; and

fig. 3 shows a further exemplary embodiment of a carrier plate for a motor vehicle transmission according to the invention.

Detailed Description

Fig. 1 shows an exemplary embodiment of a motor vehicle transmission according to the invention, having a first transmission shaft 2 and a second transmission shaft 3. The first transmission shaft 2 is rotatably mounted in a transmission housing 8 of the motor vehicle transmission 1 by means of two rolling

bearings

6, 7. The first transmission shaft 2 carries a first gear wheel 4, which is arranged between two bearing points of the transmission shaft 2. The rolling

bearings

6, 7 are preferably designed as ball bearings, tapered roller bearings or roller bearings. The first gear wheel 4 is in engagement with a second gear wheel 5, which is arranged on and carried by the second transmission shaft 3. In this case, the toothing 20 on the end face 22 of the first gear wheel 4 engages with the toothing 21 on the end face 23 of the second gear wheel 5. The second transmission shaft 3 is likewise rotatably mounted in the transmission housing 8 of the motor vehicle transmission 1 via a third rolling bearing 15 and a fourth rolling bearing 16. The gears 4, 5 are connected to the

respective transmission shaft

2, 3 in a rotationally fixed manner or can be connected to these

transmission shafts

2, 3 in a rotationally fixed manner, in particular by means of a pawl. The rolling

bearings

6, 7, 15, 16 each have an inner ring 18 and an outer ring 19, wherein a plurality of rolling bodies 24 are arranged between the inner ring 18 and the outer ring 19. At least one bearing plate 9 having a first opening 10 and a second opening 11 is arranged in the transmission housing 8, wherein the first transmission shaft 2 is guided through the first opening 10 of the bearing plate 9 and the second transmission shaft 3 is guided through the second opening 11 of the bearing plate 9.

Rolling bearings

25, 26, in which the

transmission shafts

2, 3 are rotatably mounted, are provided in the

openings

10, 11, respectively. In this case, the

transmission shafts

2, 3 are mounted by rolling

bearings

25, 26 on additional mounting points 14 between the

respective rolling bearings

6, 7, 15, 16 in order to reduce the deflection of the

transmission shafts

2, 3. Alternatively, the bearing plate 9 can also be used in place of the bearing points 6, 7, 15, 16 of the first and

second transmission shafts

2, 3. The support plate 9 can be fixed to the transmission housing 8 or another transmission component via the fixing opening 12. Alternatively, the support plate 9 can be free from direct contact with the transmission housing 8, so that sound transmission from the support plate 9 to the transmission housing 8 is suppressed. In this embodiment, the bearing plate 9 is preferably designed without a fastening opening 12 and is pushed onto the two

transmission shafts

2, 3 in such a way that the bearing plate 9 is located between the

first bearing point

6, 15 and the

second bearing point

7, 16 of the two

transmission shafts

2, 3 in the installed state and thus forms an additional bearing point 14. This achieves additional support of the

transmission shafts

2, 3, thereby reducing the deflection of the

transmission shafts

2, 3 and increasing the rigidity of the motor vehicle transmission 1. This increase in rigidity can be used to arrange a corresponding elastic receiving element 17 on the bearing points of the rolling

bearings

6, 7, 15, 16, by means of which the outer ring 19 of the rolling

bearings

6, 7, 15, 16 is decoupled from the transmission housing 8.

By the rolling of the toothing 20 of the first gearwheel 4 on the toothing 21 of the second gearwheel 5, vibrations are generated which are transmitted via the gearwheels 4, 5, the

transmission shafts

2, 3 and the rolling

bearings

6, 7, 15, 16 to the transmission housing 8. In this case, the transmission housing 8 itself is excited to vibration. The structure-borne noise is transmitted from the transmission housing 8 to vehicle components connected to the transmission housing 8, in particular to the chassis, and is emitted as sound waves from the transmission housing 8.

Propagation and transmission of the structure-borne sound waves are attenuated by the slits 27 in the support plate 9, whereby transmission noise can be minimized.

Fig. 2 shows an exemplary embodiment of a carrier plate 9 of a motor vehicle transmission 1 according to the invention. The support plate 9 has a plurality of slits 27, which locally lead to a weakening of the support plate 9. The natural vibration characteristics of the support plate 9 are thereby changed and vibrations transmitted from the rolling

bearings

25, 26 to the support plate 9 can be damped. The bearing plate 9 has a first opening 10 for receiving the first transmission shaft 2 and a second opening 11 for receiving the second transmission shaft 3. In this case, a fifth rolling bearing 25 is provided in the first opening 10 and a sixth rolling bearing 26 is provided in the second opening 11, by means of which an additional bearing point 14 for the

transmission shafts

2, 3 is obtained between the

first bearing point

6, 15 and the

second bearing point

7, 16. The slits 27 can be arranged in a circular manner, in particular around the

openings

10, 11, thereby interrupting the transmission path between the rolling

bearings

6, 7, 15, 16, 25, 26 and the transmission housing 8. The support plate 9 can be embodied as a stack of plates 30, thereby simplifying the introduction of the slit 27. In this case, the stack of metal sheets 30 is acted upon by a corresponding pretensioning force, which can be applied to the stack by means of a suitable clamping mechanism, in particular a clamping screw. Alternatively or additionally, other clamping mechanisms can be provided, in particular clamping bands or metal clamps arranged around the stack, in order to press the individual sheets 30 of the stack together and thereby to inhibit the sheets 30 from moving towards each other. The strength of the stack can be influenced by clamping, whereby the stack can attenuate different natural frequencies. In this case, a plurality of identical metal sheets 30, but also metal sheets of different thicknesses and/or metal sheets made of different materials can be stacked in order to adapt the damping characteristics to the frequency range to be damped. The support plate 9 has a fastening opening 12, by means of which the support plate 9 can be fastened to the transmission housing 8 or to another transmission component. A damping element 31 can be provided at the fastening opening 12 in order to achieve a corresponding decoupling or damping between the carrier plate 9 and the transmission housing 8.

In an alternative embodiment, the slits 27 can be filled with a vibration-damping filler material 32, which additionally also intensifies the damping effect of the slits 27.

Fig. 3 shows a further exemplary embodiment of a carrier plate 9 according to the invention of a motor vehicle transmission 1 according to the invention. In a configuration which is substantially the same as the embodiment of fig. 2, the slit 27 is formed in a meandering manner in this exemplary embodiment. The propagation of sound waves can be reduced by this shape of the slit 27, so that the structure-borne sound transmission from the bearing plate 9 to the transmission housing 8 is reduced.

List of reference numerals

1 Motor vehicle Transmission

2 (first) Transmission shaft

3 (second) Transmission shaft

4 (first) gear

5 (second) Gear

6 rolling bearing

7 rolling bearing

8 Transmission case

9 support plate

10 first opening

11 second opening

12 fixed opening

13 damping element

14 support part

15 rolling bearing

16 rolling bearing

17 receiving element

18 inner ring

19 outer ring

20 tooth part

21 tooth part

22 end side

23 end side

24 rolling element

25 rolling bearing

26 rolling bearing

27 slit

28 circular

29 zigzag shape

30 sheet material

31 damping element

32 filler material

Claims

1. A motor vehicle transmission (1) having a transmission housing (8) and a mechanism for converting a first rotary motion into a second rotary motion with a different rotational speed and/or a different direction of rotation, wherein the motor vehicle transmission (1) comprises a first transmission shaft (2) and a second transmission shaft (3) which are rotatably mounted in the transmission housing (8) by means of rolling bearings (6, 7, 15, 16), wherein the first transmission shaft (2) carries a first gearwheel (4) and the second transmission shaft (3) carries a second gearwheel (5) which is engaged with the first gearwheel (4) or is engageable with the first gearwheel (4), characterized in that the motor vehicle transmission (1) has a bearing plate (9) which comprises at least two elements for bearing the transmission shafts (2), 3) wherein a plurality of slits (27) are introduced into the support plate (9) in order to reduce the stiffness of the support plate (9) in a sub-area of the support plate (9).

2. Motor vehicle transmission (1) according to claim 1, characterised in that the carrier plate (9) has a first opening (10) and a second opening (11), wherein rolling bearings (25, 26) are provided in the openings (10, 11) of the carrier plate (9).

3. A motor vehicle transmission (1) according to claim 2, characterised in that the slits (27) are arranged circularly (28) around the respective opening (10, 11) in the support plate (9).

4. A motor vehicle transmission (1) according to claim 1 or 2, characterized in that the slit (27) has a meander shape (29).

5. The motor vehicle transmission (1) according to any of claims 1 to 4, characterized in that the carrier plate (9) consists of a plurality of sheet metal (30).

6. Motor vehicle transmission (1) according to one of claims 1 to 5, characterized in that at least two fixing openings (12) are provided on the carrier plate (9), via which fixing openings the carrier plate (9) can be fixed on another transmission component.

7. The motor vehicle transmission (1) according to one of claims 1 to 6, characterized in that the first transmission shaft (2) and the second transmission shaft (3) are supported in the transmission housing (8) on a first bearing point (6, 15) and a second bearing point (7, 16), respectively, wherein the bearing plate (9) forms at least one of the bearing points (6, 7, 15, 16).

8. The motor vehicle transmission (1) according to one of claims 1 to 7, characterized in that the slit (27) in the carrier plate (9) is filled with a vibration-damping filling material (32), in particular a plastic or foam material.

9. A method for producing a carrier plate (9) for a motor vehicle transmission (1), wherein slits (27) for locally reducing the rigidity of the carrier plate (9) are introduced into the carrier plate (9).

10. Method for manufacturing a support plate (9) according to claim 9, characterized in that the support plate (9) consists of a plurality of sheet materials (30).