EP1573222A1

EP1573222A1 - Elastic chassis bearing for utility vehicles

Info

Publication number: EP1573222A1
Application number: EP03785574A
Authority: EP
Inventors: Manfred Buhl; Ralf Kunze
Original assignee: ZF Lemfoerder GmbH
Current assignee: ZF Lemfoerder GmbH
Priority date: 2002-12-16
Filing date: 2003-12-15
Publication date: 2005-09-14
Also published as: DE10258986A1; KR20050083573A; CN1692237A; WO2004055406A1; US20050153781A1; MXPA04012964A; US7165909B2; BR0312336A; DE10258986B4; JP2006509976A

Abstract

The invention relates to an elastic chassis bearing for utility vehicles, which embodies a joint. The invention especially relates to two variations of a joint used for elastically mechanically connecting two machine parts, particularly in vehicle construction. Said elastic chassis bearing comprises a lug (1) and a housing (13, 14). The lug (1) is provided with a central area (4) and two final areas (2) and represents a rotationally symmetric swivel part while the housing (13, 14) encompasses at least two bushes (5, 6, 7; 7, 15) which are concentrically inserted into each other and jointly define a hollow cylinder. The intermediate space (8, 9, 16) of said hollow cylinder is filled with an elastic material such that the lug (1) that is embraced by the innermost bush (5, 15) can be cardanically moved relative to the other bush (7) or bushes (6, 7) of the housing (13, 14).

Description

Elastic chassis bearing for commercial vehicles

description

The present invention relates to a joint for the elastic connection of two machine parts, in particular in vehicle construction. The invention relates in particular to two variants of a joint which has a claw and a housing, the claw having a central region which is encompassed by the housing and two end regions to which one of the machine parts to be connected is fastened.

In vehicle construction, it is necessary to couple all kinds of mechanical elements at an angle. Such a mechanical connection usually takes place by means of an elastic joint, in which, among other things, a spherical connecting part, which connects the corresponding mesh elements, is enclosed by a housing. The spherical part of the connecting piece is supported in the housing in an elastic intermediate layer. The housing itself is usually pressed into a bearing eye of a motor vehicle part. Such joints are maintenance-free because the mobility is not achieved by sliding surfaces, but by deformation of the elastic intermediate layer. Because of the spherical part of the connecting piece, such a joint is referred to as a "ball joint".

Such a ball joint - in particular for pneumatic suspensions in commercial vehicles - is disclosed in EP 1 092 891 A2. The ball-and-socket joint consists of two metallic halves (half-shells) placed flat against one another with their flat sides, from which cap-shaped hemispherical or semi-ellipsoidal contours are embossed on opposite sides. The combination of these two halves results in a so-called ball piece in the middle and so-called nozzles at both ends Bores or grooves for fixing the parts to be connected elastically by means of screw connections. FIG. 8 shows one of these two halves, also called "claw". The possibility of attaching mechanical parts to these halves explains the term "claw" used for such a part. The ball piece is inserted according to FIG. 7 into a cylindrical housing and is elastically connected to it via an articulated body made of elastic material (rubber), which was introduced by means of vulcanization. By means of the ends of the two halves projecting on both sides, both claws are rigidly connected to the chassis or frame parts of the motor vehicle. In an embodiment according to FIG. 7 in particular, the fastening is carried out by means of screws which are inserted into the groove shown. The housing or housings are usually integrated in struts or handlebars which elastically connect the corresponding chassis and frame parts.

In the case of a ball piece designed as a rubber-metal part for chassis mounting according to the prior art just described, the corresponding half-shells (claws with ball piece) must be manufactured for each length variant in accordance with the required length. On the one hand, this means that a complete tool set for production is required for each variant. On the other hand, the respective production of a length variant is complex, especially since the forged part (embossed part) has so-called stiffness jumps due to its shape, which requires high-strength steel. Machining the half-shells is not sensible for cost reasons (time-consuming, high waste, etc.).

The object of the present invention is therefore to provide a joint according to the preamble of claim 1, which is easier to manufacture and more flexible to use.

The above object is achieved by a joint according to the features of claim 1. The dependent claims further develop the central idea of the invention in a particularly advantageous manner.

According to the present invention, a joint for elastic mechanical connection of two machine parts, in particular in vehicle construction, is claimed, comprising a claw and a housing, the claw having a central region which is encompassed by the housing and two end regions to each of which one of the machine parts to be connected is fastened is. The claw adjusts according to the invention The housing consists of at least two concentrically nested bushings which together define a hollow cylinder, the space between which is poured out with elastic material, so that the claw encompassed by the innermost bush relative to the other bushes of the housing is cardan, torsional and is radially and axially movable.

Such a joint according to the invention has the following advantages:

On the one hand, the external dimensions of such a housing (within an assembly) as a rubber-metal unit are always the same and can therefore be produced accordingly.

Secondly, reducing the claw to a simple turned part

- a simplified and therefore less expensive production, - the use of less expensive material (e.g. unrefined round steel),

- production only shortly before assembly or

- a quick formation of variants during assembly e.g. in an automated process.

There is also a significant reduction in the number of variants

- a relief and greater flexibility in storage,

- and a cost reduction by eliminating variant-specific tool costs (e.g. forging dies etc.) and thus

- All in all, greater flexibility in manufacturing logistics results.

The invention comprises two configurations:

A first embodiment is that the housing consists of three concentrically nested bushings. Each bushing is advantageously cylindrical and as such represents a cylinder sleeve.

For reasons of production engineering, the middle cylinder sleeve advantageously has openings, as a result of which the cavities between the inner and middle as well as middle and outer Cylinder sleeve are connected. It is therefore possible that the entire space between the innermost and outermost bushing can be filled with elastic material.

A second embodiment is that the housing consists of two concentrically nested bushings.

Advantageously, the outer bush is cylindrical and, as such, represents a cylindrical sleeve. The inner bush has two bumps in the shape of two adjacent, outwardly directed spherical segment surfaces and, as such, represents a double spherical sleeve.

The double ball sleeve is simply a cast part and can be inexpensively e.g. made of spheroidal graphite cast iron.

The machine parts are fixed to the claw in the area of the claw that is not covered by means of bores. For reasons of a better support of the parts to be fixed, the claw is milled planarly on both sides in the area of the claw that is not encompassed.

In both embodiments, it is advantageous to manufacture different assemblies of housings, each of which differs by a different outer diameter of the outer bushings, in particular the outermost bushing, and thus shows different gimbal behavior. This covers a larger area of application of the respective joint.

According to the invention, a method for producing a housing for a joint according to the preceding claims is further claimed, comprising the following steps:

(A) concentrically fixing the bushings in a casting or vulcanization mold,

(B) injecting an elastic material into the space of the hollow cylinder produced by the arrangement of the bushings,

(C) generating a prestress of the cooled elastic material. The elastic material is advantageously pressed in on the end face.

According to the invention, a pretension and an exact fit for the housing to be pressed in are produced in the cooled elastic material by cold compression of the outer bush.

In the case of a cylinder sleeve as the inner sleeve, the prestressing of the cooled elastic material is further increased by cold expansion of the innermost cylinder sleeve and an exact fit for the claw to be pressed in is produced.

In the case of a double ball sleeve as the inner bushing, the double ball sleeve is mechanically reworked to create an exact fit for the claw to be pressed in.

Further features, properties and advantages of the present invention will now be explained on the basis of exemplary embodiments and with reference to the accompanying figures of the drawings.

FIG. 1 shows in axial and transverse cross section a first embodiment of the joint according to the invention in the non-installed state,

Figure 2 shows in axial cross section the housing of the first invention

Embodiment before calibration,

FIG. 3 shows an exploded perspective view of the first embodiment in the non-installed state,

FIG. 4 shows, in axial and transverse cross section, a second embodiment of the joint according to the invention in the non-installed state,

FIG. 5 shows in axial cross section the housing according to the invention of the second embodiment before calibration, FIG. 6 shows an exploded perspective view of the second embodiment in the non-installed state,

FIG. 7 shows a perspective illustration of a joint according to the prior art in the non-installed state,

Figure 8 shows a perspective view of a half-shell of the joint shown in Figure 7.

The prior art is illustrated and explained with reference to FIGS. 7 and 8.

Figure 1 shows in axial A and transverse B cross-section a first embodiment of the joint according to the invention in the non-installed state. The joint is essentially rotationally symmetrical and consists of a housing 13 into which a claw 1 (connecting element) is pressed in the middle in a suitable fit 4. Compared to a joint according to the prior art, the claw 1 has no spherical surfaces, which is why it is referred to below as a cylinder piece 1. For the same reason, the term "ball joint" used in the prior art is not correct in this embodiment according to the invention. The joint according to the invention is therefore referred to as a cylindrical joint. The cylinder piece has 2 bores 3 in the non-pressed-in area, which make it possible to screw the parts to be connected elastically. In order to obtain a stabilizing support or fastening surface, both sides are milled at one end of the cylinder piece 10 transversely to the axis of the bore 3. The housing 13 consists of three concentrically nested cylinder sleeves 5, 6, 7 of different diameters. In the case of FIG. 1, the innermost cylinder sleeve 5 is the longest and the outer cylinder sleeve 7 is the shortest. The cylindrical cavities 8, 9 resulting from the installation geometry are filled with elastic material, preferably rubber (shown hatched). For manufacturing reasons (the manufacturing process will be discussed in more detail), the middle cylinder sleeve 6 has bores 12 (openings) through which the interior of the middle cylinder sleeve 9 is connected to that of the outer cylinder sleeve 8. The openings 12 have a diameter of several millimeters (approx. 5 mm) and can also be oval in shape. The outer cylinder sleeve 7 is - like the housing of a joint according to the prior art 18 - in a bearing eye stable part of the vehicle. The installation consists of an HIO fit; the press-in force is approx. 60kN + 10kN. In this respect, the cylinder piece 1 is gimbaled via which the parts to be connected which are movable can be flexibly coupled by means of the elasticity of the housing interior. With such a suspension there is radial mobility and cardanic up to 12 °. The maximum torsion of the cylinder joint is approximately 26 °.

A cylinder joint according to the present invention requires a suitable manufacturing process which is briefly outlined below:

Ordinary pipe sockets are used as cylinder sleeves 5, 6, 7, usually made of steel. These are inserted and fixed concentrically in a mold. At about 80 ° C and 200bar, the highly viscous or liquid elastic material (e.g. rubber) is injected on the face side. Due to the high pressure, the elastic material is distributed over the openings 12 of the central cylinder sleeve 6 in the entire interior of the housing 13. The mold has annular recesses 11 on the end faces. Such a cast housing 13 is shown in Figure 2.

After casting, the cooled elastic material must be mechanically pre-stressed so that a desired elastic behavior of the housing 13 is achieved in the cold state. Such a preload is achieved in that the outer cylinder sleeve 7 is cold-pressed from the outside in a suitable device (for example by means of press jaws), as a result of which the outer diameter is reduced by approximately 3 mm. The inner cylinder sleeve 5 is also cold expanded (for example by means of expanding jaws or mandrel) from the inside, as a result of which the inner diameter increases by approximately 2 mm. The elastic material in the interior of the housing is thus depressed, partially evades laterally and fills the recesses 11. Overall, however, the rubber receives a pretension that increases the rigidity or the elasticity of the

Cylinder joint defined. The expansion and / or compression of a cylinder sleeve 5, 7 is referred to in this context as "calibration".

In Figure 3, an exploded view of the cylinder joint is shown. The perspective view of the housing shows the staggering of the nested cylinder sleeves 5, 6, 7. The middle cylinder sleeve 6 has four bores 12 in FIG. The number of holes can vary. Except for the surfaces 10 milled transversely to the bores, the cylinder piece is clearly recognizable as a rotationally symmetrical component (in terms of production: as a turned part). The length of the cylinder piece and the spacing of the bores 3 from one another can be varied independently of the housing 13. The housing 13 in this embodiment is the same for all cylinder pieces 1. After the calibration of the housing 13, the cylinder piece 1 is pressed into the housing 13 with a fit and a defined press-in force. An h9 fit is used; the press-in force is approx. 60kN ± 10kN.

FIG. 4 shows in the axial C and transverse D cross section a second embodiment of the joint according to the invention in the non-installed state. The cylinder piece 1 is identical to the joint according to the first embodiment (ie according to the cylinder joint). The housing 14 into which the cylinder piece 1 is also pressed in the middle in a suitable fit 4 (h9 fit / press fit) is again rotationally symmetrical. In comparison to the cylinder joint, however, the housing 14 of a joint of this embodiment has only a single outer cylinder sleeve 7, which comprises a double ball sleeve 15 made of strong material. The space 16 between the cylinder sleeve 7 and the double ball sleeve 15 is filled with elastic material (e.g. rubber). The double ball sleeve 15 has a thickness of several millimeters (approx. 6 mm) and has two bump-shaped two adjacent outwardly directed spherical segment surfaces 17. According to the invention, the double ball sleeve 15 is a cast part and, as such, does not have to have high-quality material properties, in contrast to the forged half-shell 24 according to the articulated joint. For example, it makes sense to use spheroidal graphite cast iron, short name GGG-40.3.

When installed, as with the cylinder joint, the outer cylinder sleeve 7 is pressed into a bearing eye with the same fit and press-in force. The cardanic suspension of the cylinder piece 1 takes place via the double ball sleeve 15 cast in rubber, which is why the joint according to the invention of this second embodiment is to be referred to as a "double ball joint".

The manufacturing process is similar to that of the cylinder joint: The pipe socket, which represents the cylinder sleeve 7, and the cast double ball sleeve 15, which is cast on the inside and machined according to the fit, are introduced concentrically into a casting mold. The resulting cavity 16, which has annular recesses 11 on the end face due to the subsequent calibration, is cast under the same conditions with elastic material (eg rubber). A housing 14 produced in this way is shown in the uncalibrated state in FIG. 5. After cooling, only the cylinder sleeve 7 is calibrated and thus the rubber is pre-tensioned (the double ball sleeve 15 is too thick-walled to be able to widen on the inside).

FIG. 6 shows an exploded view of the double ball joint according to the invention. In contrast to the cylinder joint, the housing 14 consists of only two parts (cylinder sleeve 7 and double ball sleeve 15) which are elastically connected by means of the rubber compound. The double ball sleeve 15 as a cast part has to be reworked on the front but mainly on the inside so that the cylinder piece 1 can be fitted precisely and non-positively. The cylinder piece 1 itself is identical to that of the cylinder joint and, due to the construction of both joints according to the invention (cylinder joint and double ball joint), it can only be manufactured shortly before assembly in accordance with the latest structural dimensions.

Due to the different construction of the respective housing 13, 14 of the cylinder joint and double ball joint, both joints have different gimbal properties and, in this respect, cover a wide range of applications. The area of application is defined by the kinematic and stationary forces of the parts to be coupled in the transverse, torsional and axial directions. The field of application can be expanded according to the invention by producing the housing 13, 14 with different diameters of the outer cylinder sleeve 7. In particular, the cylinder joint can have more than three cylinder sleeves, the radii of which can additionally be varied. A housing with a larger diameter of the outer cylinder sleeve 7 is expected to be able to be used under higher loads. Special consideration is given to different assemblies, ie to housings 13, 14 with outer diameters of 55mm, 58mm, 62mm, 70mm and 75mm with a constant inner diameter of approx. 35 to 50mm. In general, it can be said that the present invention is characterized by the dissolution of claw 19, 24 and ball piece 20 of a joint according to the prior art into separate components. The claw 19, 24 is reduced to a simple cylinder piece 1; the ball piece 20 is received in a novel housing 13, 14 or its functionality is taken over or replaced by a housing 13, 14 of new construction.

Such a ball joint - in particular for pneumatic suspensions in commercial vehicles - is disclosed in EP 1 092 891 A2. In FIGS. 7 and 8, the ball joint consists of two metallic halves (half-shells) 24 with their flat sides laid flat against one another, from which cap-shaped hemispherical or semi-ellipsoidal contours 20 are embossed on opposite sides. The combination of these two halves results in a so-called ball piece in the middle and so-called connecting pieces 19 with bores 21 or grooves 22 at both ends for fixing the parts to be connected elastically by means of

Glands. FIG. 8 shows one of these two halves 24, also called "claw". The possibility of attaching 24 mechanical parts to these halves explains the term "claw" used for such a part. The ball piece is inserted according to FIG. 7 into a cylindrical housing 18 and is elastically connected to it via an articulated body made of elastic material (rubber) 23, which was introduced by means of vulcanization. Both claws are rigidly connected to the chassis or frame parts of the motor vehicle by means of the ends 19 of the two halves 24 projecting on both sides. In an embodiment according to FIG. 7 in particular, the fastening is carried out by means of screws which are inserted into the illustrated groove 22. The housing or housings 18 are usually integrated into struts or (three-point, four-point, etc.) handlebars which elastically connect the corresponding chassis and frame parts. LIST OF REFERENCE NUMBERS

1 cylinder piece (claw, connecting element)

2 not pressed area

3 hole

4 Central fit of the cylinder piece in the housing

5 innermost cylinder sleeve

6 middle cylinder sleeve

7 outermost cylinder sleeve

8 rubber-filled cavity of the outermost cylinder sleeve

9 rubber-filled cavity of the middle cylinder sleeve

10 milled end of the cylinder piece

11 annular recess in the area of the cavity

12 circular or oval openings in the middle part of the cylinder

13 Housing (rubber-metal part) of the cylinder joint

14 Housing (rubber-metal part) of the double ball joint

15 double ball sleeve

16 rubber-filled cavity of the (outermost) cylinder sleeve

17 spherical segment surfaces of the double spherical sleeve

18 cylindrical housing

19 spigot / ends of the claw

20 hemispherical or semi-ellipsoidal contour / half of a spherical piece

21 hole

22 groove

23 elastic material (rubber)

24 metallic half / half shell / claw A / C axial section

B / D transverse section

Claims

Elastic chassis bearing for commercial vehicles

1. Joint for the elastic mechanical connection of two machine parts, in particular in vehicle construction, comprising a claw (1) and a housing (13), (14), the claw (1) having a central region (4) which is separated from the housing (13) , (14) and two end regions (2) to each of which one of the machine parts to be connected is fastened, characterized in that the claw (1) represents a rotationally symmetrical rotating part and the housing (13), (14) consists of at least two concentrically nested bushings (5), (6), (7); (7), (15) which together define a hollow cylinder, the space between them

(8), (9), (16) is poured out with elastic material, so that from the innermost

Bushing (5), (15) comprises claw (1) relative to the (7) or the other bushings (6), (7) of the housing (13), (14) is gimbal, torsional and radially and axially movable.

2. Joint according to claim 1, characterized in that the housing consists of three concentrically nested bushings (5), (6), (7).

3. Joint according to claim 1 to 2, characterized in that each bush (5), (6), (7) is cylindrical and as such represents a cylinder sleeve.

4. Joint according to claim 3, characterized in that the middle cylinder sleeve (6) has openings (12) whereby the cavities between the inner (5) and middle (6) and middle (6) and outer (7) cylinder sleeve are connected.

5. Joint according to claim 4, characterized in that the entire space (8), (9) between the innermost (5) and outermost (7) bushing is poured out with elastic material.

6. Joint according to claim 1, characterized in that the housing consists of two concentrically nested bushings.

7. Joint according to claim 6, characterized in that the outer sleeve (7) is cylindrical and as such represents a cylinder sleeve and the inner sleeve (15) has a double hump shape two adjacent outwardly directed spherical segment surfaces (17) and as such represents a double spherical sleeve.

8. Joint according to claim 7, characterized in that the double ball sleeve (15) is cast from cast iron or nodular cast iron.

9. Joint according to claim 1 to 8, characterized in that the fixing of the machine parts on the claw (1) in the not included area (10) of the claw (1) via bores (3).

10. Joint according to claim 9, characterized in that in the non-encompassed area (10) of the claw (1) it is milled planar on both sides transversely to the bores (3).

11. Joint according to claim 1 to 10, characterized in that different assemblies of housings (13), (14) are made, which are characterized by a different outer diameter of the outer bushings (6), (7), in particular the outermost bushing (7 ), differentiate and thus show different gimbal behavior.

12. A method for producing a housing (13) or (14) for a joint according to the preceding claims 1 to 11, comprising the following steps:

(A) concentrically fixing the bushings (5), (6), (7); (7), (15) in a casting or vulcanization mold,

(B) injecting an elastic material into the spaces of the hollow cylinder produced by the arrangement of the bushings,

(C) generating a prestress of the cooled elastic material

13. The method according to claim 12, characterized in that the elastic material is pressed in on the end face.

14. The method according to claim 12 to 13, characterized in that a prestress is generated in the cooled elastic material by cold compression of the outer sleeve (7).

15. The method according to claim 12 to 14, characterized in that - in the case of a cylinder sleeve as an inner sleeve - the bias is generated or amplified by cold expansion of the innermost cylinder sleeve (5).

16. The method according to claim 12 to 14, characterized in that - in the case of a double ball sleeve as an inner sleeve - the double ball sleeve (15) is reworked to produce a fit for the claw (1) to be pressed.