DE2028176A1 - Plain bearings, especially for universal joints in gearshift and steering devices of motor vehicles - Google Patents

Description

Lemford Metallwaren AG, Lemförde / Hann.

"Plain bearings, in particular for universal joints in switching and steering devices of motor vehicles ¹¹

The invention relates to a plain bearing, in particular for universal joints in switching and steering devices of motor vehicles that consist of an external rigid bearing link made of metal or the like. and an inner one The sliding bush is made of plastic.

To make such joints as easy and cheap as possible to be able to, one strives to the exact processing of the Eliminate bearing surfaces of the articulated links or limit them to a minimum. For this purpose, the Sliding bushes made of plastic in such a way that the plastic used as a bearing material in a Injected annular cavity formed between the metallic bearing members or in some other way is introduced with the aim of being between the outer circumferential surface to create an adhesive bond between the sliding bush and the inner surface of the outer metallic bearing member, the inner peripheral surface of the plastic sleeve then forming the sliding surface with respect to the part to be supported.

However, such a plain bearing has various shortcomings the use of plastic as a sliding layer has grown shown that there is a sufficient adhesive bond between this material and the metal surface of the outer bearing member cannot be achieved without additional precautions. At least

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the metal surface must be roughened or it is provided with indentations or openings around the molded To anchor plastic more or less securely. But that requires a corresponding processing of the parts, which the manufacture of the bearing and its assembly becomes complicated and expensive

In the case of bearings produced in this way, it is also disadvantageous that there is an exact or even predeterminable running clearance between the sliding surfaces as a result of the changes in cross-section of the bearing material that occur when the plastic cools cannot be easily achieved with these bearings, i.e. precise and uniform storage on the does not enter the entire bearing surface of the journal.

The object of the invention is to create a plain bearing that is simple in construction and is easy and inexpensive can be produced in which no harmful deformations of the bearing surfaces are to be expected and that in addition to favorable Load conditions for the storage elements met after an exact and pre-determinable running clearance between the sliding surfaces.

Accordingly, the invention consists in the fact that on the one hand the required running clearance between the sliding parts and on the other hand, a sufficient tight fit of the sliding bush the part to be supported, for example a pivot pin, utilizing the shrinking effect of the sliding bush forming plastic is generated.

The manufacture of the bearing takes place in accordance with the invention Way that the plastic for the sliding bushing is inserted in one through the outer bearing member and one in this

1 0 9 8 5 1 / U 9 2 originally inspected

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cylindrical mold core formed annular space is injected or poured, such that the molded piece as a result of the shrinkage that occurs when the plastic cools, of the inner surface serving as a mold wall of the outer bearing member releases and after removal of the mold core with a diameter that is reduced compared to this is pressed together with the bearing link onto the part to be stored with pretension.

With a sliding bearing designed and manufactured according to the invention, various advantages are achieved.

An advantage of the invention is that, despite cheap production of the bearing, an accurate and predictable one Bearing play can only be achieved by appropriate selection of the journal diameter, the diameter of the pivot pin to be stored in the area of the shrinkage dimension of the sliding bushing smaller, equal or larger than the diameter of the cylindrical mold core used when injecting the plastic. Same So bearings with the same journal diameter always have that same running clearance, the clearance tolerance being approximately the same as the journal tolerance.

Another notable advantage arises from the fact that taking advantage of the strong shrinkage of the plastic that occurs as a result of the large coefficient of thermal expansion A sufficiently tight fit of the sliding bush on the pivot pin is achieved without additional anchoring will.

The shrinkage of the plastic further ensures that the required clearance between the inner surface of the

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The outer bearing member and the outer surface of the sliding bushing arise, ie the sliding surfaces are shifted further outward from the pivot pin to be supported. This leads to a noticeable reduction in the specific load on the sliding surface. For example, in the case of a bearing journal with a diameter of 13 mm and a wall thickness of the sliding bushing of 2 mm, the specific load on the sliding surfaces would be reduced by about 24%.

In terms of cheap production of plain bearings, it is particularly advantageous if the outer bearing member a thin-walled bearing sleeve is used, which is chipless in the deep-drawing process with completely smooth surfaces Can be produced inexpensively, since this involves any sewing work not applicable.

In order to carry out the procedure, it is also advisable to one and optionally also the other edge of the outer bearing member before the introduction of the plastic to be crimped in such a way that it forms a closed mold space together with the cylindrical molding die.

In the drawing, the inventive slide bearing and its production is shown schematically in an exemplary embodiment.

The illustration shows a bearing open on one side in a longitudinal section. In this version, mainly for the support the pin of universal joints is used, the outer bearing member is denoted by 1, which is also the bearing housing forms for the remaining bearing elements. This bearing link consists of a thin-walled, non-cutting drawn sleeve made of sheet steel, which is closed on one side by a bottom 2 and

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if desired, only after their shaping hardened, but no longer needs to be reworked. In through the crimped Eandflansch 3 of the bearing sleeve 1 limited opening is a cylindrical punch A with a retracted opposite its diameter Approach 5 used, the approach serving as a mandrel. The annular cavity thus formed is up through the Stamp 4 · surrounding flange 3 of the bearing sleeve 1 covered. In the punch 4 is a 5 above the core approach . Funnel-shaped inlet 6 provided on the transition surface 7 opens between the punch and the core extension into the mold space, and through which the liquid plastic is injected into the mold space.

When the mold space is filled with the plastic, a strong shrinkage of the material occurs during cooling a, whereby the shaped piece, namely the sliding bush 8, is released from the inner wall surface of the bearing bush 1 and its diameter after removal of the mold core is approximately equal to | decreased. When using one like that manufactured bearing bushes can now optionally be stored pivot pins that are in the range of the shrinkage dimension have different diameters, namely smaller, equal to or larger than the diameter of the mold core. It will when the sliding bushing is pressed onto the bearing journal in one operation, together with the bearing sleeve 1, a solid one Achieved a shrink fit of the sliding bushing and at the same time a storage of the pin with a precise desired Running play ^ between the bearing bush 1 and the sliding bush 8 in a simple manner, i.e. without costly reworking without the need for special means to ensure a good bearing fit. The assembly of the bearing is also very easy.

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Claims (4)

Claims Plain bearings, in particular for universal joints in switching and steering devices of motor vehicles, consisting from an outer rigid bearing member made of metal or the like and an inner sliding bush made of suitable, in particular abrasion and oil-resistant plastic, thereby characterized in that on the one hand the required running clearance between the sliding parts and on the other hand a sufficient tight fit of the sliding bush on the part to be supported, for example a pivot pin, is generated using the shrinkage effect of the plastic forming the sliding bush. 2.) A method for producing a plain bearing according to claim 1, ^v characterized in that the plastic for the sliding bushing is introduced into a fiingraum formed in a manner known per se by the outer bearing member and a cylindrical mold core inserted into it, in such a way that The molded part is released from the inner surface of the outer bearing member, which serves as a mold wall, as a result of the shrinkage that occurs when the plastic cools down and, after removal of the mold core, with a diameter that is smaller than this, is pressed onto the part to be stored with pretensioning together with the outer bearing member. 3 · Plain bearing according to claims 1 and 2, characterized in that that the one and possibly also the other band of the outer bearing member before the introduction of the plastic is crimped in such a way that it is together 10 9 8 5 1/1 4 9 2 202 «176 forms a molding space with the cylindrical molding die. 4. Plain bearing according to claim 1 ■■ - 3 »characterized in that that the outer bearing member is made from a non-cutting thin-walled bearing sleeve. 4.6.70 Le / L GRiGINAL INSPECTED 109851/1492 Blank page