Metal working – Method of mechanical manufacture – Spring making
Reexamination Certificate
2000-04-28
2002-04-02
Hughes, S. Thomas (Department: 3726)
Metal working
Method of mechanical manufacture
Spring making
C029S896930, C267S141200, C267S293000
Reexamination Certificate
active
06363613
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
Not Applicable
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable
MICROFICHE APPENDIX
Not Applicable
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a bearing of the type mentioned in the precharacterizing clause of patent claim
1
.
Stabilizing torsion bars are torsion spring bars, used in motor vehicle construction, which serve for stabilizing against tilt and torsion of the body when a motor vehicle is cornering. Such stabilizing torsion bars, referred to below in brief as“torsion bar”, extend, as a rule, over the entire width of the vehicle and are arranged in the region of the front axle and in the region of the rear axle, that is to say with two such torsion bars for each vehicle. Such torsion bars for tilt stabilization are therefore relatively large structural parts with a clear longitudinal extent of the order of magnitude of around 1.5 m.
In motor vehicle construction, such stabilizing torsion bars cannot be screwed, for example positively screwed or riveted, metal-on-metal to the chassis, on the one hand, and to the body, on the other hand. If such a type of fastening were adopted, they would transmit all the wheel noises and road noises, via the solid-borne sound bridges thus formed, to the body and therefore also to and into the passenger cell. The torsion bars must therefore be arranged so as to be mounted in an uncoupling, at least insulating manner, in order to prevent the described conduction of solid-borne sound. For this purpose, sleeve bearings have been used on the torsion bar shoulders for many decades. Such sleeve bearings have typically a rigid outer sleeve and, coaxially in the latter, a rigid inner sleeve, sometimes also an inner bolt, and also an elastomeric packing, more precisely an elastomeric buffer, which connects to one another the two rigid sleeves lying one in the other and separates the two sleeves acoustically from one another. In this case, this interruption of the solid-borne sound bridge also separates the connecting elements of the chassis and of the body, said connecting elements in each case engaging on one of the two sleeves of the sleeve bearing which lie one in the other. In this context, the body may be connected, for example via a screw bolt, to the inner sleeve and the torsion bar may be connected via a connecting lug or a bearing shell. Alternatively, the torsion bar shoulder serves as an inner bolt and is connected via an inner sleeve to the uncoupling elastomer of the sleeve bearing, whilst the outer sleeve or else, directly, the outer cylindrical surface of the rubber sleeve is connected to the body via a bearing shell. In particular, innumerable arrangements for these connections are known from the commonly accepted prior art, but do not alter the basic function of such a torsion bar bearing.
Both in large heavy commercial vehicles and in passenger cars driven at higher speeds, considerable forces occur on such torsion bar bearings, specifically both rotational forces and translational forces. In such cases, these forces, which occur unavoidably as a consequence of functioning, have to be absorbed solely by the rubber packing and the tying of the latter to the two connecting elements of the sleeve bearing, specifically the inner sleeve and outer sleeve. The use of structural elements making a positive connection, such as, for example, the use of disks or of bolts passing through the connecting elements, is not possible, since such structural elements stabilizing the sleeve bearing would produce solid-borne sound bridges which would nullify the intended function of interrupting the solid-borne sound path, which is precisely the reason for the bearing.
The development of torsion bar bearings must accordingly concentrate on providing the best possible nonpositive, integral or positive connection of the elastomeric packing to the inner sleeve or the inner bolt and the outer sleeve or the externally adjoining bearing shell or bearing block shell, said connection being capable of absorbing the high translational and rotational dynamic forces which occur. If the connecting elements are not tied to the elastomeric sleeve in such a permanently dynamically fixed way, a dynamic load on the bearing results in frictional noises and in creaking due to relative movements between the elastomeric block and the connecting element, such noises and creaking being disturbingly audible right into the passenger cell of the motor vehicle. Moreover, such relative movements between the connecting elements and the uncoupling elastomeric buffer cause appreciable wear both of the elastomer and, in particular, of the inner connecting element. In addition to the disturbing noises produced, therefore, wear of the structural elements of the sleeve bearing and consequently a reduction in the service life of the bearing come about.
2. Description of the Related Art
Researchers have been working for more than half a century on a satisfactory solution to this technical problem, not only for torsion bar bearings, but also for related sleeve bearings with a similar bearing function. In this context, many of the known solution proposals amount merely to generating the highest possible prestress for the rubber sleeve of the bearing, in order thereby to improve permanently the frictional connection between the inner and outer axial surfaces of the rubber sleeve and the connecting elements. One example of such attempts at solving the problem is known from the American Patent U.S. Pat. No. 2,346,574 of 1942 and from the German preliminary publication DE 16 25 561 A1, Austrian Patent AT 357 882 A or, more recently, European preliminary publication EP 893 291 A1. At the same time, it is likewise already known, for example from the last-mentioned European Patent Specification EP 893 291 A1, to improve the frictional connection between the elastomeric sleeve and the connecting elements by additional adhesive bonding.
Furthermore, it is also known from the commonly accepted prior art to insert the bearing portion of the torsion bar directly into a die and to vulcanize the elastomeric sleeve directly onto the torsion bar. In this method, a torsion bar bearing constructed in this way initially has good bonding properties, at least on the torsion-bar side, but, because of the bulkiness of the torsion bars, has the disadvantage of an unproductive manufacturing method which leads to high manufacturing costs. Moreover, torsion bars provided in this way with vulcanized-on elastomeric sleeves are susceptible to corrosion as a consequence of the method used.
Finally, for sleeve bearings with a similar technical problem, but with smaller and less bulky components, it is also already known to insert the two mutually concentric connecting parts of such a bearing, which lie one in the other, into a die, injection-mold around them in a single injection cycle and vulcanize them out, as is the case, for example, with a pendulum support (DE 196 31 893 A1) or with a steering rod on a chassis block (EP 684 404 A1). However, because of the bulkiness of the torsion bars, the use of this method for the manufacture of torsion bar bearings would lead to production costs which, from the outset, would rule out manufacturing torsion bar bearings in this way from an appropriate industrial mass production process.
BRIEF SUMMARY OF THE INVENTION
Proceeding from this prior art, the technical problem on which the invention is based is to provide an economical method for manufacturing torsion bar bearings of the abovementioned type, which reliably rules out, in the long term, relative movements in the separating plane between the elastomeric sleeve and the connecting elements, even under high bearing load, and consequently leads to“silent” torsion bar bearings with an increased service life.
The invention solves this technical problem by means of a method for the manufacture of torsion bar bearings, more precisely torsion bar shoulder bearings, which has the features mentioned in claim
1
.
The method acco
Koczar Peter
Schleinitz Uwe
Wolf Franz Josef
Butler Marc W.
Hughes S. Thomas
WOCO Franz-Josef Wolf & Co.
Yeager Arthur G.
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