Patent Publication Number: US-10330149-B2

Title: Method for producing a bearing, and bearing

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of U.S. patent application Ser. No. 14/778,895, filed on Sep. 21, 2015 which is a U.S. national phase of application No. PCT/EP2014/053208, filed Feb. 19, 2014, which claims priority from German application No. DE10 2013 204 995.1, filed Mar. 21, 2013, each of which is herein incorporated by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to a method for producing a bearing, in particular a hydraulic axle support bearing. 
     BACKGROUND OF THE INVENTION 
     The axle support bearings known in the prior art generally have an inner part made of aluminium, a radial channel, an outer part and an elastomeric region which is arranged between the inner part and the outer part. The elastomeric region is reinforced by a steel cage or a plastic cage which has the advantage of reducing the weight of the bearing substantially. A steel cage is embedded into the rubber of the elastomeric region, for example, and then completely surrounded by the rubber. In contrast, in the configurations known from the prior art, in which a weight-reducing plastic cage is used, only some areas of said cage are surrounded by the elastomeric region. A bearing configured as an elastomeric bush bearing is known from DE 10 2007 022 410 A1. 
     Axle support bearings configured as described above need to be calibrated however. This is relatively uncomplicated if steel cages are used and the bearing is calibrated prior to assembly. Further calibration is then performed after assembly which ensures both tightness and dimensional stability. During the latter calibration, several markings are pressed inwards at the periphery wherein the material of the outer part is pressed over the edge of the cage. This serves to connect the outer part to the inner part in the direction of extrusion in a form fit manner over the elastomeric region. However, as already stated, bearings with steel cages are very heavy. 
     If, on the other hand, the cage is made of plastic, calibration to apply increased compressive prestressing in the elastomeric region is difficult. However, this is necessary in terms of useful life, characteristic curve ratio and tight fitting of the plastic cage in the arrangement. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is therefore to provide a method for producing a weight-reducing bearing with plastic cage, by means of which calibration can be performed in a simple and cost-effective manner. A bearing with reduced weight produced accordingly should also be provided. 
     This object is achieved through a method for producing a bearing having the features described herein. 
     A method for producing a bearing, in particular a hydraulic axle support bearing, is provided, wherein the method comprises the following steps: preassembling an inner part in an outer part with an elastomer body which is arranged in between and is reinforced by a plastic cage, which at least partially bears against an inner wall of the outer part, wherein the plastic cage is designed to protrude radially over an upper edge and a lower edge of the outer part and, at the lower edge of the outer part, to project beyond the latter; and simultaneously calibrating the outer part and the plastic cage by constricting the outer part and the plastic cage from a respective first diameter to a respective second diameter which is smaller than the respective first diameter, wherein, after the constriction, the plastic cage likewise projects over the upper edge of the outer part for the form-fitting axial securing of the outer part. 
     The method enables easy and thus cost-effective calibration of both the outer part and, at the same time, the plastic cage in a single method step. The outer part is connected to the plastic cage in a form fit manner in the end position which effects the required axial securing of the outer part. By way of an example, this also renders the markings and indentations on the outer part used in the prior art unnecessary. 
     Preferably, there is clearance, in particular of 2 mm, during the pre-assembly step. Moreover, it is preferred if the measurement of the constriction of the outer part from the first diameter to the second diameter is greater than the above mentioned clearance, more particularly that the constriction measures more than 3 mm, preferably approx. 4 mm. 
     Preferably, the outer part is simply slid onto the inner part with the elastomer body and the plastic cage from above in the pre-assembly step. 
     Furthermore, it is advantageous if the elastomer body is connected to the plastic cage in a vulcanisation step, wherein the plastic cage is inserted into a tool in a substantially form fit manner. This will prevent an undesirable deformation of the plastic cage during the vulcanisation process. 
     A bearing, more particularly a hydraulic axle support bearing, with an inner part, an outer part and an elastomer body which is arranged in between and is reinforced by a plastic cage, is also provided, wherein the outer part has an upper edge and a lower edge and wherein the plastic cage projects over the upper edge and the lower edge of the outer part for the form fit axial securing of the outer part. Reinforcement by a cage made of plastic compared with a cage made of steel reduces the weight substantially, which in turns leads to a reduction in CO 2  emissions in automotive engineering. Cost savings are also possible as a result of this. Furthermore, using plastic for the cage offers the advantage of more options in terms of design. 
     According to a preferred embodiment, the plastic cage bears at least partially against an inner wall of the outer part, wherein the contact region of the plastic cage on the inner wall of the outer part preferably constitutes more than 20% of the curved surface area of the inner wall. 
     Preferably, the plastic cage has at least one sealing groove, more particularly a plurality of sealing grooves arranged on an outer side of the plastic cage, which groove is opposite the inner wall of the outer part, wherein the at least one sealing groove is filled with an elastomer material. Preferably, the at least one sealing groove is filled with the elastomer material of the elastomer body which can take place in one method step during production. 
     According to a further preferred embodiment, the plastic cage has at least one web region, more particularly a plurality of web regions, which are lined at least in part. The lining gives the web regions increased stability. The web regions themselves serve to prevent the constriction or even closure of bearing channels during the calibration process. 
     Preferably, the radial stop is made of plastic. This will achieve a lower overall weight. According to a further preferred embodiment, the radial stop is configured as an upper radial stop and arranged on an upper edge of the bearing. 
     Embodiments of the invention are described in greater detail below with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A-1E  show different views of a bearing according to one embodiment; 
         FIGS. 2A-2D  show different views of a bearing according to a further embodiment; 
         FIGS. 3A-3F  show different further views of a plastic cage according to one embodiment; and 
         FIGS. 4A-4F  show different views of a plastic cage according to a further embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 1A to 1E  show different views of a bearing  1  configured as a hydraulic axle support bearing according to one embodiment wherein  FIG. 1A  represents an isometric view of the bearing  1 ,  FIG. 1B  a sectional view through the bearing  1 ,  FIG. 1C  another sectional view through the bearing rotated 90° about the longitudinal axis L,  FIG. 1D  a top view of the bearing  1  and  FIG. 1E  a view from below. As can be seen particularly from  FIG. 1B , the bearing  1  has an inner part  2 , a substantially hollow cylindrical outer part  3  made of aluminum and an elastomer body  21  arranged between the inner part  2  and the outer part  3 . The elastomer body  21  forms balancing chambers  5  in fluid communication with each other on radially opposing sides over a radial channel  14 . The right-hand balancing chamber  5  shown in  FIG. 1B  opens radially in the inside into a recessed filling channel  8  in the inner part  2 . Furthermore, a radial stop  4  made of plastic is arranged on an upper edge of the bearing thus forming an upper radial stop. The upper radial stop is mounted on top of the inner part  2 . 
     The elastomer body  21  is vulcanised onto the inner part  2 . Moreover, a further stop is provided as lower radial stop  9  on an axial end of the inner part  2 , which supports an axial stop  10 , which is mounted on a front side end or on the bottom side  6  of the inner part  2 . The lower radial stop  9  is also made of plastic. The axial stop is made of aluminium. 
     The elastomer body  21  is reinforced by a plastic cage  11 , which is vulcanised into the elastomer body  21 . Sections of the plastic cage  11  bear against an inner wall  7  of the outer part  3 . A lower axial end  12  and an upper axial end  12 ′ of the plastic cage  11  (see  FIGS. 1B and 1C ) are each formed radially outwards at 90° in order to project over a lower edge  13  and an upper edge  13 ′ of the outer part  3  thereby axially securing the outer part  3  in a form fit manner, and consequently the outer part  3  is held securely in an axial direction relative to the plastic cage  11  and thus the elastomer body  21 . 
     Furthermore, the plastic cage  11  has web regions  15 , which can be lined in order to demonstrate increased stability. The web regions  15  prevent constriction or closure of the radial channel  14  during the calibration process. 
       FIGS. 2A to 2D  show different views of a bearing  1  configured as a hydraulic axle support bearing according to a further embodiment, wherein  FIG. 2A  represents an isometric view of the bearing  1 ,  FIG. 2B  a sectional view through bearing  1 ,  FIG. 2C  a top view of the bearing  1  and  FIG. 2D  a view of the bearing  1  from below. The design of the bearing  1  shown here essentially corresponds to the design of the bearing  1  shown in  FIGS. 1A to 1E  and only differs in terms of the design of the axial stop  10  on the lower end of the bearing  1 . 
     The bearing  1 , which is shown in  FIGS. 2A to 2D , as well as the bearing  1 , which is shown in  FIGS. 1A to 1E , is produced as follows. In a preassembling step, the inner part  2 , the elastomer body  21 , the radial channel  14  and the outer part  3  made of aluminium are assembled loosely such that the plastic cage  11  is arranged directly on the inner wall  7  of the outer part  3 . The hollow cylindrical outer part  3  is slid on from above here. The plastic cage  11  protrudes radially over the outer part  3  at both ends thereof, i.e. on the upper and lower edges  13 ,  13 ′. In this uncalibrated state, the plastic cage  11  projects over the outer part  3  only on the lower edge  13 . In a subsequent calibration process, the aluminium outer part  3  is constricted, i.e. the diameter of the outer part  3  is reduced by approx. 4 mm. However, not only the diameter of the outer part  3  is reduced in the process, but also the diameter of the plastic cage  11  in the same step. Clearance of 2 mm is assured with the loose pre-assembly. The resulting constriction of the plastic cage is therefore approx. 2 mm in diameter. Thus, both the outer part  3  and the plastic cage  11  are calibrated in a single method step. After calibration, the plastic cage  11  then also projects over the outer part  3  on the upper edge  13 ′ thereof and consequently creates the required axial securing against sliding in an upwards direction. 
       FIGS. 3A to 3F  show different further views of a plastic cage  11  according to one embodiment, wherein  FIG. 3A  represents an isometric view of the plastic cage  11 ,  FIG. 3B  a sectional view through the plastic cage  11 ,  FIG. 3C  a further sectional view through the plastic cage  11  which, compared with the sectional view in  FIG. 3B , is rotated 90° about the longitudinal axis L of the plastic cage  11 ,  FIG. 3D  a detailed view of the upper edge  16  of the plastic cage  11 ,  FIG. 3E  a view of the plastic cage  11  from below and  FIG. 3F  a top view of the plastic cage  11 . As can be seen here, the plastic cage  11  has two of the web regions  15  described above. Furthermore, the plastic cage  11  has a plurality of sealing grooves  18  on its outer side  20  on an upper section  17  and on a lower section  17 ′, which sealing grooves are opposite the inner wall  7  of the outer part  3  in the assembled state of the bearing  1  (see, for example,  FIG. 1B ). The sealing grooves  18  are filled with elastomer material during the process of spraying the elastomer body  21 . 
     Moreover, it can be seen in the detailed view of the upper edge  16  of the plastic cage  11  shown in  FIG. 3D  (characterised by A in  FIG. 3B ), that the upper edge  16  curves outwards and is thus rounded. In contrast to this, the lower protruding edge  16 ′ of the plastic cage  11  is not curved. 
       FIGS. 4A to 4F  show different views of a plastic cage  11  according to a further embodiment, wherein  FIG. 4A  represents an isomeric view of the plastic cage  11 ,  FIG. 4B  a sectional view through the plastic cage  11 ,  FIG. 4C  a further sectional view through the plastic cage  11 , which compared with the sectional view in  FIG. 4B , is rotated 90° about the longitudinal axis L of the plastic cage  11 ,  FIG. 4D  a detailed view of the upper edge  16  of the plastic cage  11  (characterised by A in  FIG. 4B ),  FIG. 4E  a view of the plastic cage  11  from below and  FIG. 4F  a top view of the plastic cage  11 . The embodiment of the plastic cage  11  shown here differs from the embodiment shown in  FIGS. 3A to 3F , firstly in that the upper edge  16  of the plastic cage  11 , which is shown in detail in  FIG. 4D , is rounded, but not does not curve outwards, and secondly in that the lower edge  16 ′ is provided with two conical support contours  19 ,  19 ′ that point downwards and are angled slightly outwards. 
     Thus, while there have been shown, described, and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions, substitutions, and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit and scope of the invention. For example, it is expressly intended that all combinations of those elements and/or steps that perform substantially the same function, in substantially the same way, to achieve the same results be within the scope of the invention. Substitutions of elements from one described embodiment to another are also fully intended and contemplated. It is also to be understood that the drawings are not necessarily drawn to scale, but that they are merely conceptual in nature. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto. 
     Every issued patent, pending patent application, publication, journal article, book or any other reference cited herein is each incorporated by reference in their entirety.