CN112739921A

CN112739921A - Acoustically optimized bearing unit

Info

Publication number: CN112739921A
Application number: CN201980059363.3A
Authority: CN
Inventors: 马丁·克虏伯
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Technologies AG and Co KG
Priority date: 2018-10-30
Filing date: 2019-09-11
Publication date: 2021-04-30
Also published as: KR20210081327A; DE102018127029A1; WO2020088709A1; KR102784626B1

Abstract

The invention relates to a bearing unit (10) for supporting a shaft, the unit having a bearing (12) with an inner ring (14) and an outer ring (16), wherein the inner ring (14) and the outer ring (16) Circumferentially rotatable relative to each other, and the outer ring (16) has an outer curved flank (18), while the bearing (18) also has an axis of rotation (R) and is supported relative to at least one revolution ring (20) , wherein the bearing ( 18 ) is swivelable relative to the rotary ring ( 20 ) about at least one rotary axis (S) oriented transversely to the axis of rotation (R), wherein the rotary ring ( 20 ) has at least one inner surface designed as a spherical arch (22), the inner surface is designed relative to the outer curved flank (18) of the outer ring (16) so as to form a contact zone (24) in which the turning ring (20), the inner ring (14) and the outer ring (16) Arranged coaxially to one another, the turning ring ( 20 ) has a recess ( 26 ) in the circumferential direction (U), which extends over the entire width of the turning ring. Thereby a bearing unit (10) with good acoustic properties and easy to manufacture and assemble is created.

Description

Acoustically optimized bearing unit

Technical Field

The invention relates to a bearing unit for mounting a shaft, having a bearing with an inner ring and an outer ring, wherein the inner ring and the outer ring are rotatable circumferentially relative to one another, wherein the outer ring has an outer curved side, wherein the bearing also has a rotational axis, and wherein the bearing is supported relative to at least one swivel ring, during which the bearing can swivel relative to the swivel ring about at least one swivel axis oriented transversely to the rotational axis, wherein the swivel ring has at least one inner surface designed as a spherical arch, which inner surface is designed relative to the outer curved side of the outer ring, such that a contact region is formed between these surfaces, wherein the swivel ring, the inner ring and the outer ring are arranged coaxially with respect to one another.

Background

Drives with worm shafts and worm gears are commonly used in electric power assisted servo steering systems. The worm shaft is typically supported in fixed and floating bearings. In some applications, the fixed bearing is designed as a slewing bearing and the wear in the tooth engagement and the shaft roll can be readjusted. The swivel function is achieved by using a separate swivel ring with an internal ball, which locates the spherical ball bearing outer race. An electric power steering system is an electric power steering system that is active only when steering motions occur. For electromechanical drives, a servo motor controlled by a program supports and superimposes the steering movement of the driver on the mechanical means of the steering system, i.e. on the steering column or the steering gear. Electric Power Steering (EPS) and electric power steering (EPAS) systems are known, in which hydraulic devices are always omitted in these systems. This eliminates the need for a servo pump, a hose leading from the servo pump to the steering gear and back again, hydraulic oil and a slave piston.

The bearing structure of the electric power assisted servo steering system is manufactured with high precision because the ball arches should be as free of play as possible to ensure low noise operation of the bearing unit without generating rattling. The outer race and the swivel ring form a pair of spherical arches which are manufactured with precisely defined tolerances and are distributed according to several tolerance groups. The swivel ring has an assembly window for guiding and swiveling the spherical outer ring.

A bearing unit according to the state of the art is known, for example, from DE 102007044618 a 1. The invention relates to a bearing unit, by means of which a worm spindle for a power steering system is mounted in a pivotable manner. The bearing is secured in a pivotable manner by two outer rings which can be connected to one another by means of connecting elements in order to achieve a variable relative position, so that the lateral surfaces of the outer bearing shell of the bearing are free of play, while at the same time a certain degree of rotational freedom is ensured about the pivot axis.

Disclosure of Invention

The object of the invention is to provide an alternative bearing unit which has good acoustic properties, is easy to assemble, and has an outer ring and a swivel ring which are easy to produce, wherein the bearing unit can readjust wear and shaft tilting in the toothing.

According to the invention, this object is achieved by a rolling bearing having the features of claim 1. Preferred embodiments of the invention are given in the dependent claims and in the subsequent description, which are able to demonstrate the inventive aspects, individually or in combination.

The invention relates to a bearing unit for mounting a shaft, having a bearing with an inner ring and an outer ring, wherein the inner ring and the outer ring are rotatable circumferentially relative to one another, wherein the outer ring has an outer curved side, wherein the bearing further has a rotational axis, and wherein the bearing is supported relative to at least one swivel ring, during which the bearing can swivel relative to the swivel ring about at least one swivel axis oriented transversely to the rotational axis, wherein the swivel ring has at least one inner surface designed as a spherical arch, which inner surface is designed relative to the outer curved side of the outer ring, so that a contact region is formed, wherein the swivel ring, the inner ring and the outer ring are arranged coaxially with respect to one another. The turn ring has a recess in the circumferential direction, which extends over the entire width of the turn ring.

The width of the swivel ring is the width of the swivel ring over the entire extension of the rotational axis.

Recesses are provided which extend over the entire width of the swivel ring in order to be able to easily fit bearings, preferably rolling bearings, most preferably ball bearings, into the swivel ring, wherein the mounted bearing units have good acoustic properties. The good acoustic properties result in particular from the spring tension present in the contact region, i.e. the contact region between the inner surface of the swivel ring designed as a spherical arch and the outer curved flank of the outer bearing. Due to the constant pulling force in the aforementioned contact area, noise generation due to rattling is avoided.

It is highly preferred to manufacture the recess, in the region of which a groove is provided, which groove is further processed into the recess.

The turn-around ring is particularly designed to be resilient, so that the recess supports the resilient effect of the turn-around ring.

In addition to the recess, a rotationally symmetrical swivel ring is preferably provided. Preferably with a spherical arch in its interior.

In particular, the rotating ring is made of a hardenability material such as 100Cr 6. Thanks to this feature, it is particularly desirable to notch the turn-around ring by means of laser beam cutting and therefore to be easy to manufacture.

Alternatively, the rotating ring may be made of a non-hardenability material, such as case hardened steel or a sintered material. This makes it possible to saw the rotary ring particularly easily in order to produce grooves in the rotary ring.

It is very preferably provided that the outer ring and the turn ring are designed to overlap each other. This overlap can be understood here analogously to an interference fit. Since the swivel ring is designed in particular to be elastic, in this preferred case the swivel ring acts like a spring, which pretensions the ball arch without play. This feature can be used for a play-free mounting of the shaft, wherein after the assembly of the pivot bearing into the steering gear housing, it can be fixed by means of a nut in a force-locking or form-locking manner. After tightening the nut, the elastic pretension will remain.

An alternative to a play-free bearing is: the swivel ring has at least one elastic sheathing element, in particular an O-ring, on the outer side in the circumferential direction. A swivel ring with an elastic ring or an elastic sheath or the like can realize permanent elastic pretension after assembly. The elastic assembly also ensures noise decoupling or damping during operation.

At least in the contact region, the outer ring and/or the slewing ring can very preferably have a coating for reducing friction. By a coating for reducing friction is meant a coating having a coefficient of friction less than or equal to that of molybdenum disulfide or manganese phosphate. Molybdenum disulfide or manganese phosphate are highly preferred coatings for the outer ring and/or the slew ring.

According to a method for manufacturing a bearing unit according to the invention, which has at least one of the aforementioned features, it is provided that the turn ring has at least one groove for forming the recess. The groove is correspondingly loaded or deformed so that it breaks over the entire width of the turn-around ring and thus forms a recess. The swivel ring is correspondingly elastically expanded, so that the bearing to be mounted can be inserted. After the slewing ring and the bearing to be mounted have the respective mounting positions, this expansion of the slewing ring is correspondingly released, so that the slewing ring circumferentially surrounds the bearing. The expansion is therefore only used for the transition. This represents an easy assembly, wherein the outer ring and the turn ring are easy to manufacture.

According to a preferred measure, the grooves for manufacturing the bearing unit may originate from the following situation: the groove is already provided when the green body of the turn circle is manufactured or is made by means of a laser beam. A swivel ring made of a hardenability material, preferably 100Cr6, is particularly suitable for this.

According to an alternative measure for producing the groove, provision is made for the groove to be produced by a separate production method, for example by sawing or cutting. The cutting can preferably be performed by means of a laser or a water jet. As an alternative, these manufacturing measures for the grooves are particularly suitable for a swivel ring made of a non-hardenability material. The slew ring is then most preferably made of case hardened steel or sintered material.

The invention also relates to a slewing ring with at least one of the aforementioned features for a bearing with at least one of the aforementioned features.

Drawings

The invention is described below with reference to the accompanying drawings, which illustrate preferred embodiments, wherein the features described below are able to show aspects of the invention both individually and in combination. Brief description of the drawings:

FIG. 1: a bearing unit according to the state of the art is shown in a side view,

FIG. 2: the bearing unit of figure 1 is shown in a vertical cross-section view in section a-a,

FIG. 3: in accordance with a side view of a first embodiment of the bearing unit according to the principles of the present invention,

FIG. 4: the bearing unit of figure 3 is shown in a vertical cross-sectional view in section B-B,

FIG. 5: in figures 3 and 4 a perspective view of the bearing unit,

FIG. 6: the bearing unit in fig. 3, 4 and 5 is shown in a vertical sectional view, arranged in a servo steering housing,

FIG. 7: in accordance with a side view of a second embodiment of the bearing unit according to the principles of the present invention,

FIG. 8: the bearing unit of figure 7 is shown in a vertical cross-section view in section C-C,

FIG. 9: perspective views of the bearing unit in fig. 7 and 8, an

FIG. 10: the bearing unit in fig. 7, 8 and 9 is shown in a vertical sectional view, arranged in a servo steering housing.

Detailed Description

Fig. 1 shows a bearing unit 10 according to the state of the art in a side view. The bearing unit 10 has a bearing 12 with an inner race 14 and an outer race 16. The inner race 14 and the outer race 16 are circumferentially rotatable relative to each other about an axis of rotation R.

The bearing 12 is supported relative to at least one swivel ring 20 and can swivel relative to the swivel ring 20 about at least one swivel axis R oriented transversely to the swivel axis R.

In fig. 2, a section a-a of the bearing unit 10 in fig. 1 is shown in a vertical sectional view. It can be seen that the turn ring 20 has an inner surface 22 designed as a spherical arch, which is designed relative to the outer curved side surface 18 of the outer ring 16 to form a contact area 24. The turn ring 20, the inner ring 14 and the outer ring 16 are arranged coaxially with each other.

As can be seen from fig. 1 and 2, a rotary ring 20 according to the state of the art has two diametrically opposed fitting windows 28, which are designed in the form of slots around the circumference of the rotary ring 20 and extend in particular maximally over half the width of the rotary ring into the interior of the rotary ring 20. The width of the turn circle is the width of the rotation axis R of the turn circle 20 over the entire extension axis. The mounting window 28 is used to guide the outer ring 16 and to pivot the outer curved side 18 together. The outer race 16 having such outwardly curved sides 18 is also referred to as a spherical outer race.

Fig. 3 shows a bearing unit 10 according to a first embodiment of the invention in a side view. The bearing unit 10 has a bearing 12 with an inner race 14 and an outer race 16. The inner race 14 and the outer race 16 are circumferentially rotatable relative to each other about an axis of rotation R.

The bearing 12 is supported relative to at least one swivel ring 20 and can swivel relative to the swivel ring 20 about at least one swivel axis S oriented transversely to the axis of rotation R.

In fig. 4 a section B-B of the bearing unit 10 in fig. 3 is shown in a vertical sectional view. It can be seen that the turn ring 20 has an inner surface 22 designed as a spherical arch, which is designed relative to the outer curved side surface 18 of the outer ring 16 so that a contact zone 24 is formed between the surfaces. The slewing ring 20, the inner ring 14 and the outer ring 16 are arranged coaxially with one another with respect to the axis of rotation R.

Fig. 3 to 6 also show that the rotary ring 20 has a recess 26 in the circumferential direction U, which extends over the entire width of the rotary ring. The width of the turn circle is the width of the rotation axis R of the turn circle 20 over the entire extension axis.

According to a first embodiment, a spring pretension is formed between the outer ring 16 and the rotary ring 20, which is designed in particular to be elastic, and is retained after assembly, wherein the outer ring 16 and the rotary ring 20 are designed to overlap one another. This means that there is an interference fit.

Fig. 6 shows how the bearing unit 10 according to the first embodiment is arranged in the servo steering housing 30. For this purpose, a bearing unit 10 can be provided, which serves in particular for supporting the worm shaft. This applies in particular to systems with servo steering housing 30 and according to electric power steering (EPAS). The pivot bearing 20 is fixed in a force-fitting or form-fitting manner by a nut 32. In particular, the fastening is effected by an elastic pretensioning which is generated by the overlapping of the rotary rings 20. With this fixing method, a fixed, at the same time releasable connection can be advantageously established for the bearing unit 10 in the servo steering housing 30.

According to the invention, in the first and second embodiment and in the embodiment not shown, the bearing unit 10 can optionally be fixed in the servo steering housing 30 in a particularly force-fitting or form-fitting manner by means of a nut 32.

Fig. 7 shows a bearing unit 10 according to a second embodiment of the invention in a side view. The bearing unit 10 has a bearing 12 with an inner race 14 and an outer race 16. The inner race 14 and the outer race 16 are circumferentially rotatable relative to each other about an axis of rotation R.

In fig. 8 the bearing unit 10 of fig. 7 is shown in a vertical sectional view in section C-C. It can be seen that the turn ring 20 has an inner surface 22 designed as a spherical arch, which is designed relative to the outer curved side surface 18 of the outer ring 16 so that a contact zone 24 is formed between the surfaces. The slewing ring 20, the inner ring 14 and the outer ring 16 are arranged coaxially with one another with respect to the axis of rotation R.

Fig. 7 to 10 also show that the rotary ring 20 has a recess 26 in the circumferential direction U, which extends over the entire width of the rotary ring. The width of the turn circle is the width of the rotation axis R of the turn circle 20 over the entire extension axis.

According to a second embodiment, an elastic pretensioning is formed between the outer ring 16 and the rotary ring 20, which is designed in particular to be elastic, and is retained after assembly, wherein the rotary ring 20 has at least one elastic jacket element 36 on the outside in the circumferential direction U. In fig. 8, 9 and 10, it is shown that over the entire width of the swivel ring two elastic jacket elements 36 are provided spaced apart from one another, in particular as O-rings.

Fig. 10 shows how the bearing unit 10 according to the second embodiment is arranged in the servo steering housing 30. For this purpose, a bearing unit 10 can be provided, which serves in particular for supporting the worm shaft. This applies in particular to systems with servo steering housing 30 and according to electric power steering (EPAS). The slewing bearing 20 is fixed in the servo steering housing 30 by a snap ring 34. In particular, the fastening is effected by an elastic pretensioning, which is generated by the rotary ring 20 by means of the elastic jacket element 36. With this fixing method, a suitable, at the same time releasable connection can advantageously be established for the bearing unit 10 in the servo steering housing 30.

According to the invention, in the first and second embodiment and in the embodiment not shown, the bearing unit 10 can optionally be fixed in the power steering housing 30 in a particularly force-fitting or form-fitting manner by means of a snap ring 34.

Description of the reference numerals

10 bearing unit

12 bearing

14 inner ring

16 outer ring

18 side surface of the outer ring

20 turn circle

22 inner surface

24 contact zone

26 recess

28 fitting window

30 servo steering housing

32 nut

34 clasp

36 elastic sheath element

R rotating shaft

S rotating shaft

In the U circumferential direction

Claims

1. A bearing unit for supporting the shaft, having

A bearing (12) with an inner ring (14) and an outer ring (16), wherein the inner ring (14) and the outer ring (16) are rotatable circumferentially relative to each other, and the outer ring (16) has an outer curved side surface (18),

the bearing (18) also has a rotational axis (R) and is supported relative to at least one swivel ring (20), wherein the bearing (18) can swivel relative to the swivel ring (20) about at least one swivel axis (S) oriented transversely to the rotational axis (R),

wherein the turn ring (20) has at least one inner surface (22) designed as a spherical arch, which is designed relative to the outer curved lateral surface (18) of the outer ring (16) to form a contact region (24),

wherein the rotary ring (20), the inner ring (14) and the outer ring (16) are arranged coaxially with one another,

it is characterized in that the preparation method is characterized in that,

the rotary ring (20) has a recess (26) in the circumferential direction (U), which extends over the entire width of the rotary ring.

2. Bearing unit according to claim 1, wherein the outer ring (16) and/or the slewing ring (20) have a friction-reducing coating at least in the contact region (24).

3. Bearing unit according to claim 1 or 2, having a molybdenum disulphide or manganese phosphate coating for reducing friction.

4. Bearing unit according to any of the preceding claims, wherein the outer ring (16) and the swivelling ring (20) are of overlapping design with respect to each other.

5. Bearing unit according to any of the preceding claims, wherein the swivel ring (20) has at least one elastic jacket element 36, in particular an O-ring, outside in the circumferential direction (U).

6. Bearing unit according to any of the preceding claims, wherein the slewing ring (20) is made of a hardenability material, preferably 100Cr 6.

7. Method of manufacturing a bearing unit (10) according to one of the preceding claims,

-the turn-around ring (20) has at least one groove so as to form a recess (26),

-loading the groove accordingly so that it breaks over the entire width of the revolution and thus forms a recess (26),

-elastically expanding the swivel ring (20) accordingly, so that the bearing (12) to be mounted can be inserted, and

-correspondingly releasing this expansion of the slewing ring (20), thereby allowing the slewing ring (20) to circumferentially surround the bearing (12).

8. Method for manufacturing a bearing unit (10) according to the preceding claim, characterized in that the groove is already provided when manufacturing the green ring, or is made by means of a laser beam.

9. Method for manufacturing a bearing unit (10) according to any of claims 7 and 8, characterized in that the groove is made by a separate manufacturing method, such as by sawing or cutting, wherein the rotating ring (20), in particular case hardened steel or sintered material, is preferably made of non-hardenability material.

10. Slewing ring of a bearing unit (10) according to any of the preceding claims, characterized by the features of the slewing ring (20) according to any of the preceding claims.