DE102021204163B3 - Bearing assembly, method of manufacturing a bearing assembly - Google Patents

Abstract

The invention relates to a bearing arrangement (1) with a bearing bush (2) and with a bearing body (3) which can be pressed into the bearing bush (2). In order to create a bearing arrangement that is simple in construction, has an increased extrusion force compared to the prior art and is easy to assemble, a metal foam structure (5) is arranged at least in regions between the bearing bush (2) and the bearing body (3), with the help of which the bearing body (3) is fixed in the pressed-in state in the bearing bush (2) by friction and/or positive locking.

Description

The invention relates to a bearing arrangement for mounting a drive unit or a chassis part of a vehicle, having: a bearing bush and having a bearing body which can be pressed into the bearing bush, according to the preamble of claim 1. The invention also relates to a method for producing such a bearing arrangement.

For the articulated connection of chassis parts of a vehicle to each other or to a chassis of the vehicle, as well as to connect a unit of a vehicle to the chassis of the vehicle, bearing bodies in the form of elastomer-metal bearings are preferably used. Such bearing bodies are pressed into bearing bushes, resulting in a non-positive press fit, which can be additionally combined with form-fitting elements and reinforced. The degree of tolerance overlap between an outside of the bearing body and an inside of the bearing bush determines the tight fit of the chassis part or the unit connected accordingly via the bearing body.

A pressing force required to press the bearing body out of the bearing bush is generally used as a determinant for the tight fit of the bearing body. In turn, connecting elements of a chassis part or an assembly of the vehicle engage in such an elastomer-metal bearing or are connected to it in some other way.

the EP 2 456 995 B1 describes an elastomer-metal bearing consisting of an inner holding part in the form of a hollow cylinder with a circular ring cross-section, an elastomer element surrounding it and a hollow-cylindrical metal outer shell surrounding it. The outer shell is designed in the manner of a collar bush, with recesses arranged on its peripheral surface. With its outer shell, the elastomer-metal bearing is pressed into a bearing bush. Here form-fitting elements, which protrude from the contour of the inside of the bearing bush, engage in the recesses on the peripheral surface of the collar bush. A combined force-form fit is effected between the elastomer-metal bearing and the bearing bush.

the DE 10 2009 051 159 A1 describes a bearing arrangement with a bearing bush and with a bearing body which can be pressed into the bearing bush. The bearing body is formed as a rubber-metal bearing. The bearing bushing has supporting sections arranged offset to one another, and a projection pointing radially inwards is provided in one or more supporting sections. On its peripheral surface, the rubber-metal bearing in turn has indentations adapted to the support sections and their projections. In each case, a projection of a respective support section engages in a recess of the rubber-metal bearing in a form-fitting manner, as a result of which the pressing-out forces of the bearing arrangement are increased.

the DE 10 2019 132 875 A1 describes a composite bushing that may include a center plate and an outer foam that is disposed outside of the center plate to surround the center plate and that is made of different types of materials.

Also describes the DE 10 2009 031 063 A1 a roller bearing arrangement with at least one outer bearing ring and at least one inner bearing ring as well as rolling elements guided in raceways between them, wherein at least one damping body is provided for mechanical vibration damping, which reduces the vibration transmission to at least one subsequent component in the power flow. According to the invention, it is provided that at least one damping body is made of a composite material with at least one bearing ring.

The bearing arrangements according to the prior art are not optimized with regard to their production costs, their extrusion forces and also with regard to their assembly effort and in this regard still leave something to be desired. For example, before they are assembled, volatile lubricants have to be introduced between the bearing body and the bearing bush, which makes handling them complicated when they are assembled.

Proceeding from this state of the art, the invention is based on the object of creating a bearing arrangement which is of simple construction, has an increased pressing force compared to the prior art and is easy to assemble.

The object is achieved with a bearing assembly having the features of patent claim 1 in its entirety. Furthermore, the object is achieved by a method having the features of claim 11.

Because a metal foam structure is arranged at least in regions between the bearing bush and the bearing body, with the aid of which the bearing body is fixed in the pressed-in state in the bearing bush by frictional and/or positive locking, a bearing arrangement is created that is easy to manufacture and reproducible with regard to is their tolerances, which can be assembled with little handling effort and which has greater extrusion forces than known bearing arrangements each of comparable size. In the case of the bearing arrangement according to the invention, there are also no additional machining steps that improve the frictional connection between the bearing body and the bearing bush, such as surface machining, for example.

The bearing arrangement can be manufactured in a simple manner and always exhibits reproducible, high extrusion forces after assembly.

Metal foam structures, which are used in the bearing arrangement according to the invention and its individual components according to the independent claims, are generally a composite of two-phase systems consisting of gaseous bubbles and solid metal walls. Metal foam structures are manufactured specifically and can have open or closed pores. They can be produced in various ways, with a metal powder advantageously being mixed with a blowing agent powder for the production of such metal foam structures for bearing arrangements or on surfaces of components of bearing arrangements. This mixture is applied to the designated surfaces, mostly metal surfaces, and compacted. The mixture is then heated to temperatures above the melting range of the selected matrix alloy (aluminium), whereby the embedded blowing agent releases gas and the metal matrix expands. The blowing agent has a gas release temperature matched to the melting temperature of the metal matrix. After the metal foam structure has cooled, it can also be further processed mechanically.

Merely by the inventive arrangement of metal foam structures and their dimensioning with the aid of a tool, a bond between the bearing body and the bearing bush is achieved with an increased extrusion force. Contrary to prior art bearing arrangements, there is no need for a design effort to arrange interlocking interlocking elements on the bearing body and bearing bush or additional handling steps such as the application of adhesive or other liquid auxiliary materials for assembly.

In an exemplary embodiment of the bearing arrangement that can be produced particularly cost-effectively, the metal foam structure is applied to an outside of the bearing body, and its external dimensions can be determined by a tool that is placed around the bearing body during the foaming process of the metal foam. Consequently, this defines the interference fit between the bearing body and the bearing bush and their pressing-out force.

It can be advantageous to prefabricate the metal foam structure before it is attached to an outside of the bearing body that faces the inside of the bearing bush in the assembled state. For this purpose, a sleeve, for example made of an aluminum alloy, can be provided with the metal foam on its outside. A material connection between the sleeve and the metal foam is technically possible here, so that a semi-finished product can also be produced from a metal tube with a metal foam structure attached on the outside as bar material, from which suitable length sections can then be cut off, which then form the sleeve.

The metal foam structure can be present on the metal tube at least in a compacted form—not yet foamed—and only be foamed by heating in a later processing step, after the sleeve sections have been cut off. This creates a bearing arrangement that is very easy to manufacture and whose components can be handled.

In a further exemplary embodiment, the metal foam structure can be a component of the bearing bush, preferably attached to its entire inner side. Depending on the selected handling and production steps when manufacturing the bearing arrangement, it can also be advantageous to position and press the metal foam structure as an independent component, even without being arranged on an additional sleeve, between the bearing body and the bearing bush.

In principle, the metal foam structure can have a circular cross-sectional shape or a cross-sectional shape that deviates from the circular shape. As a result, the shape of the bearing body with the metal foam structure can be produced in a simple manner and can be adapted to the respective design requirements.

In principle, a metal outer sleeve of the bearing body can also be formed exclusively from the metal foam structure.

The bearing arrangement is particularly advantageous as an elastomer-metal bearing for connecting chassis parts to axle parts of a vehicle or for connecting chassis parts to aggregate components of a vehicle, since the bearing arrangement enables short production and assembly times, and large numbers of vehicles can therefore be equipped with it.

Elastomer-metal bearings have an outer sleeve that serves as a bearing seat, which is attached to the named vehicle components via a bearing bushing can be attached. An elastomeric element is inserted into the outer sleeve, with a metal bushing being inserted or pressed into a through-opening, usually running in the longitudinal direction of the elastomeric element. The bushing can accept a bolt or other fastener. Instead of the socket, a fastening element, such as a screw spindle, can be vulcanized directly to the elastomer element or connected in some other way.

The metal foam structure can be formed by a foamable metal layer applied to the outside of the bearing body and/or to the inside of the bearing bush. As mentioned, the foamable metal layer can be foamed under the action of heat and using shaping tools on the bearing body and on the bearing bush and brought to a defined tolerance level.

The resulting outer surfaces of the bearing body and the bearing bush from the metal foam structure are porous and rougher than the smooth and uncoated surfaces of bearing bodies and bearing bushes according to the prior art and represent a measure to increase the coefficient of friction even in the uncompressed state. The metal foam structure can have an open-pore or closed-pore surface structure . Due to the selected excess dimensions of the metal foam structure on the bearing body relative to the bearing bush receiving it, the surface of the metal foam structure breaks up when pressed with the bearing bush and jams with the inside of the bearing bush or vice versa. This creates a combination of bearing body and bearing bush that is form-fitting and non-positive and has an increased extrusion force compared to the prior art.

In addition, it can be advantageous to attach positive-locking elements on and/or in the bearing body, the bearing bush and/or the metal foam structure, which engage in complementary positive-locking elements in the bearing body or the bearing bush.

• - Bereitstellen eines Lagerkörpers und einer Lagerbuchse, wobei eine Außenseite des Lagekörpers und/oder eine Innenseite der Lagerbuchse eine verschäumungsfähige Metallschicht trägt,
• - Aufschäumen und zumindest teilweises Aushärten der verschäumungsfähigen Metallschicht unter Wärmeeinwirkung,
• - Einpressen des Lagerkörpers in die Lagerbuchse.

In accordance with the above statements, the invention also relates to a method for producing a bearing arrangement with the steps:

• - providing a bearing body and a bearing bush, wherein an outside of the bearing body and/or an inside of the bearing bush carries a foamable metal layer,
• - foaming and at least partial curing of the expandable metal layer under the action of heat,
• - Pressing the bearing body into the bearing bush.

The invention also relates to the smallest tradable units of the bearing arrangement, namely a bearing body with a metal foam structure for a bearing arrangement according to the invention, a bearing bushing with a metal foam structure for a bearing arrangement according to the invention and a sleeve, preferably made of an aluminum alloy, with a metal foam structure for a bearing arrangement according to the invention.

The metal foam structure can be formed from a foamed aluminum alloy.

• 1 eine schematische, perspektivische Ansicht eines ersten Ausführungsbeispiels einer erfindungsgemäßen Lageranordnung, vor deren Montage,
• 2 eine weitere schematische, perspektivische Ansicht eines zweiten Ausführungsbeispiels einer erfindungsgemäßen Lageranordnung, vor deren Montage,
• 3 einen teilweisen, schematischen Querschnitt durch eine Metallschaumstruktur im geschäumten Zustand auf einer Aluminiumhülse aufgebracht,
• 4 einen teilweisen schematischen Querschnitt durch die Metallschaumstruktur in 3 im verpressten Zustand,
• 5 eine schematische, perspektivische Ansicht eines Hilfsrahmens einer Hinterachse eines Fahrzeugs, der über erfindungsgemäße Lageranordnungen mit einem Chassis oder einer Karosserie des Fahrzeugs verbunden werden kann,
• 6a einen schematischen Querschnitt durch ein rohrförmiges Stangenmaterial mit an seiner Außenseite kompaktiert aufgebrachter, verschäumungsfähiger Metallschicht; und
• 6b einen schematischen Querschnitt durch das Stangenmaterial in 6a nach Verschäumen der Metallschicht.

The invention is explained below using exemplary embodiments in the drawings. Show it:

• 1 a schematic, perspective view of a first embodiment of a bearing arrangement according to the invention, before assembly,
• 2 a further schematic, perspective view of a second embodiment of a bearing arrangement according to the invention, before assembly,
• 3 a partial, schematic cross section through a metal foam structure in the foamed state applied to an aluminum sleeve,
• 4 a partial schematic cross section through the metal foam structure in 3 in pressed condition,
• 5 a schematic, perspective view of a subframe of a rear axle of a vehicle, which can be connected to a chassis or a body of the vehicle via bearing arrangements according to the invention,
• 6a a schematic cross section through a tubular rod material with a compacted, foamable metal layer applied to its outside; and
• 6b a schematic cross section through the rod material in 6a after foaming of the metal layer.

In 1 is a schematic, perspective view of a bearing assembly 1 is shown for connecting an in 5 shown chassis part 13, which is formed as a subframe 15 of a rear axle, is used with a chassis, not shown. The bearing assembly 1 is shown in the unassembled state and consists of a bearing bush 2, from which 5 four in total pieces are arranged at respective corners of the auxiliary frame 15, and a bearing body 3.

The bearing bush 2 is formed in the manner of a cylindrical sleeve and is welded to the auxiliary frame 15 in each case. In the exemplary embodiment shown, its diameter is greater than its height. The bearing body 3 can be pressed into the bearing bushing 2 , resulting in a combined form-fit connection between the bearing bushing 2 and the bearing body 3 according to the invention. The bearing body 3 is provided for fixing the auxiliary frame 15 to a chassis (not shown) or a body of the vehicle.

In order to enable a particularly simple production of the bearing body 3 and the bearing bushing 2 and to be able to press them easily, a layer of a metal foam structure 5 arranged around the entire circumference of the bearing body 3 is provided. The metal foam structure 5 is materially connected to a surface area 4, in this case the entire outside 11 of the bearing body 3.

As shown by an arrow M, the bearing body 3 is pressed in the axial direction with the bearing bushing 2 .

3 shows such a metal foam structure 5 in a partial, schematic cross section, which is applied to a metal sleeve 7 in a materially bonded manner. The metal sleeve 7 is an outer sleeve of the bearing body 3 and forms its outside 11.

The metal foam structure 5 is formed by bubbles that are surrounded by a metal membrane and assume a spherical shape. The metal membranes touch at points or surfaces and thus form a very light structure, which in the in 3 example shown is closed-pore.

A surface 6 of the metal foam structure 5 can be formed around the metal sleeve 7 with a defined spacing by using, for example, a tool in the form of a mold or a shell frame. This results in a defined tolerance for producing a press fit in the bearing bush 2. The metal foam structure 5 is therefore a component of an outside of the bearing body 3.

In 4 the bearing body 3 with its metal foam structure 5 in the pressed state with the bearing bushing 2 is shown in a partial, schematic cross section. When pressed, the metal bubbles of the outer layer of the metal foam structure 5 break and form a compressed edge area 16 which exerts a radially directed force P on an inside 8 of the bearing bush 2 . In addition, the broken walls of the metal foam bubbles cant and form a positive connection between the bearing body 3 and the bearing bush 2 in addition to the frictional connection represented by the force P.

The in the 1 and 2 Bearing arrangement 1 shown is formed as a bearing arrangement 1 for an elastomer-metal bearing 10 . As 3 shows, an elastomer body 17 is arranged on the inside of the metal outer sleeve 7 .

In the elastomeric body 17, which is often formed like a cylinder and has a through hole, a bearing 18 engages with a cylindrical screw bolt, which is not shown. Overall, the result is a support of the auxiliary frame 15 on the vehicle that is flexible about all spatial axes, and vibrations and structure-borne noise are prevented or dampened from being transmitted from the running gear to the chassis and in particular to the body of the vehicle.

2 shows a further exemplary embodiment of a bearing arrangement 1 according to the invention, in which, in addition to the metal foam structure 5, which is also divided here into two annular surface areas 4, positive-locking elements 14 are arranged on the outside 11 of the bearing body 3, which after the pressing of the bearing body 3 and the bearing bush 2 engage in not shown recesses on the inside 8 of the bearing bush 2 and thus improve the form fit. Otherwise, the same reference numerals apply to the same components as in FIG 1 .

In 6a a sleeve 9 is shown in a schematic cross section, to which a foamable metal layer 12 is applied. Both parts - sleeve 9 and metal layer 12 - are formed from an aluminum alloy. After exposure to heat, the component foams and increases in diameter 6a , like this the 6 b indicates.

the 6a and 6b each represent manageable units of semi-finished products that can be cut, for example, into sections of different lengths and can be arranged on the outside 11 of a bearing body 3 .

Reference List

1

bearing arrangement

2

bearing bush

3

bearing body

4

surface area

5

metal foam structure

6

surface, v. 5

7

metal outer sleeve

8th

inside, v. 2

9

sleeve

10

Elastomer-Metal Bearing

11

outside, v. 3

12

Metal layer, expandable

13

undercarriage part

14

interlocking element

15

subframe

16

edge area

17

elastomer body

18

In stock

M

pressing direction

P

power

Claims (11)

Bearing arrangement for mounting a drive unit or a chassis part (13) of a vehicle, having: a bearing bush (2) and a bearing body (3) which can be pressed into the bearing bush (2), characterized in that between the bearing bush (2) and the bearing body (3) a metal foam structure (5) is arranged at least in regions, with the aid of which the bearing body (3) is fixed in the pressed-in state in the bearing bush (2) by frictional and/or positive locking. bearing arrangement claim 1 , characterized in that the metal foam structure (5), at least in the pressed-in state of the bearing body (3) in the bearing bush (2), has a broken surface (6) through which the frictional and/or positive connection between the bearing body (3) and the Bearing bush (2) is effected. Bearing arrangement according to one of Claims 1 or 2 , characterized in that the metal foam structure (5) is part of - an outside (11) of the bearing body (3), or a metal outer sleeve (7) of the bearing body (3), or - the bearing bush (2). Bearing arrangement according to one of Claims 1 until 3 , characterized in that an inner side (8) of the bearing bush (2) is formed in one piece with or from the metal foam structure (5). Bearing arrangement according to one of Claims 1 or 2 , characterized in that the metal foam structure (5) is arranged as an independent component between the bearing body (3) and the bearing bush (2). Bearing arrangement according to one of Claims 1 until 5 , characterized in that the metal foam structure (5) is sleeve-like. bearing arrangement claim 4 , characterized in that the metal outer sleeve (7) of the bearing body (3) is formed in one piece with or from the metal foam structure (5). Bearing arrangement according to one of Claims 1 until 7 , characterized in that the bearing body (3) is formed as an elastomer-metal bearing (10). Bearing arrangement according to one of Claims 1 until 8th , characterized in that the metal foam structure (5) has an open-pore or closed-pore surface structure. Bearing arrangement according to one of Claims 1 until 9 , characterized in that at least one form-fitting element (14) is arranged on and/or in the bearing body (3) and/or the bearing bush (2) and/or the metal foam structure (5) to increase a pressing force of the bearing body (3). A method of manufacturing a bearing assembly comprising the steps: - providing a bearing body (3) and a bearing bush (2), the outside (11) of the bearing body (3) and/or the one inside (8) of the bearing bush (2) carrying a foamable metal layer (12), - foaming and at least partial curing of the foamable metal layer (12) under the action of heat, - Pressing the bearing body (3) into the bearing bush (2).

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