DE102006042551A1 - Plain bearings for high operating temperatures - Google Patents

Abstract

A sliding bearing, in particular for a conveyor belt in an oven, with a bearing sleeve 1, on which a roller 2 is rotatably arranged, is characterized in that the roller 2 has a metal ring 2a in which a carbon ring 2b is arranged inside.

Description

The The invention relates to a sliding bearing according to the preamble of the claim 1, in particular for a conveyor belt for transporting baked goods through an oven, with a bearing sleeve, on which a roller is rotatably arranged.

bearings are sufficient in the prior art known. As bearing materials are regularly bronze, white metals, Lead-acid metals, aluminum alloys, plastics as well as ceramics as well as fiber reinforced Ceramic used. From the Internet (http: \ en.wikipedia.org \ wiki \ Lager_ (Technik)) is a sliding bearing is known in which coal used as a bearing material becomes. It is stated that this Kohleleitlager then advantageous is when electrical currents are transmitted through bearings Need to become. For bearings, the friction coefficient increases with higher load and thus increasing Temperature, however, significantly. Therefore, it is noted that carbon also used in brake discs.

Out For this reason, it has been refrained from, Kohlegleitlager in a hot one Environment, such as that found in an oven, to use. For the storage of conveyor belts for the transport of baked goods an oven therefore uses ball bearings. Because the ball bearings subject to a permanent, strongly fluctuating temperature influence, their lifespan is not very big. It is therefore often necessary replace the ball bearings. Because to replace the ball bearings of the Operation of the oven must be interrupted, this is very disadvantageous.

It The object of the invention is an initially mentioned sliding bearing of this type to train it for high Operating temperatures and high mechanical loads is suitable.

The solution This object is apparent from the features of the characterizing Part of claim 1. Advantageous developments of the invention emerge from the dependent claims.

According to the invention is a plain bearing, especially for a conveyor belt for transport of baked goods through an oven, with a bearing sleeve on a roller is rotatably arranged, characterized that the roller has a metal ring in which a cabbage ring inside is arranged.

Thereby, that the roller has a metal ring in which a cabbage ring inside is arranged, the sliding bearing is on the outside as robust as a plain bearing Metal. Because of the strength of steel, the metal ring is convenient designed as a steel ring. Advantageously, the outer ring a hitherto in a conveyor belt for the transport of baked goods used an oven used ball bearings.

Thereby, that the steel ring has a Kohlering inside, receives the sliding bearing the properties of a carbon plain bearing. That means it can to be dispensed with lubrication.

In order to the Kohlering arranged in the metal ring by means of a press fit can be, the Kohlering should have a correspondingly high stability. The wall thickness of the Kohlerings is therefore according to a particular embodiment of the invention equal to or greater than the wall thickness of the metal ring.

Especially an embodiment is advantageous the invention, wherein the Kohlering formed in a on the bearing sleeve Ring groove is arranged. This is the Kohlering against direct external influences protected. In particular, the Kohlering is against the action of heat radiation or protected from an open flame. The arrangement in the annular groove is the risk of damage to the Kohlerings lowered, thereby increasing the reliability and significantly increases the life of Kohlerings. Through the lateral wall of the Ring groove receives the Kohlering lateral support, which is significant the stability Kohlerings and thus the plain bearing effects.

Very advantageous in the latter embodiment is when the bearing sleeve has a circular collar, the height of the wall thickness of the Kohlerings corresponds, and arranged on the bearing sleeve a disc is whose outer diameter the outer diameter of the collar corresponds. Through the collar and the disc is in the Principle formed an annular groove in which the Kohlering is arranged.

The the Kohlering facing side of the collar and the disc are as well as the lateral surface the bearing sleeve sanded in an advantageous manner. This results in a very low friction between the Kohlering and the bearing sleeve.

In Advantageously, the disc has a in the radial direction extending opening on. This makes it possible the disc on the bearing sleeve to fix. The disc is conveniently fixed on the bearing sleeve, that the Kohlering in the axial direction almost free of play on the bearing sleeve is arranged. This also has a very positive effect on the Durability of the Kohlerings out. The Kohlering sits with namely axial play on the bearing sleeve, There is a risk that the Kohlering wears faster and the Roller starts to stumble.

Very an embodiment is also advantageous the invention, wherein the bearing sleeve is a in the radial direction extending opening having. This makes it possible the bearing sleeve for example, on a dividing pin of a transport chain fix. By fixing it is achieved that the Laufrol le not on the bearing sleeve can rotate, thereby precluding a resulting wear is. The rotational movement thus takes place only between the bearing sleeve and the Kohlering.

In Advantageously, the opening in the bearing sleeve corresponds with the opening in the disc, so that disc and bearing sleeve, for example by means of a common clamping ring can be fixed.

When very beneficial has turned out that the Kohlering a sliding material consisting of the essential filler contains graphitized carbon black, whose Pores are filled with metallic or non-metallic materials. In the case of the essentially made of carbon sliding material The plain bearing can be a metal, a metal alloy or a ceramic-filled, porous Carbon body the functionally essential part of a crystallographic contains comparatively poorly ordered graphite based on Rußkoks act. The introduced metal or the introduced metal alloy is according to their behavior under the environmental conditions such as high temperature, Air contact or the presence of lubricating additives select. The metals antimony, nickel, silver, copper, aluminum and magnesium and alloys of these metals are particularly well suited for this purpose. When However, antimony has proven particularly advantageous. It can but also carbonized synthetic resins and / or pitches as impregnation of the porous one Carbon body be used.

Very advantageous for the long-term stability especially under the environmental conditions mentioned is a lower Ash content of the graphitized carbon black coke, being particularly is advantageous if the sliding material graphitized soot of less as 1 weight percent. This results in a particularly high long-term stability of the sliding material achieved under the specified conditions of use.

Very an embodiment is also advantageous the invention in which the sliding material as additional Components of synthetically produced graphite or natural graphite and / or inorganic additives contains. This ensures that the wear is additionally reduced.

in the The following is the preparation of the graphitized Rußkokses invention described. The starting material is any soot suitable. Preferably used one over commercially available Pigment or filler black, the have been produced according to defined procedures and which have a low Have content of ash and hydrocarbons. residual contents hydrocarbons in the carbon black for soot coke production are not unfavorable.

Of the Soot is optionally using facilitating aids like tars, oils or organic solvents in a known manner with a cokeable, hydrocarbon-containing Binder mixed to form a plastic mass. Preferably is a commercially available as a binder Bindepech used. The added amounts of binder are in Range of 35 to 65 weight percent based on the finished mixture (= 100 weight percent). The mixing process is preferably above the softening point or range of the binder. The way The mixture obtained is then molded into intermediate bodies and becomes these bodies Excluding oxidizing media for coking the contained Binder component fired to temperatures of 800 to 1400 ° C. The resulting Rußkokskörper be then excluding oxidants to graphitization temperature, preferably 2300 to 3100 ° C, heated. One to less than 100 weight percent graphitized soot coke existing sliding material is obtained, by making a dry mix which is 70 to 99 weight percent graphitized carbon black contains. The mixtures containing less than 100 percent by weight graphitized soot coke can exist in addition one or more synthetically produced graphites, such as electrographite, Lonza graphite or Kish graphite or natural graphite and inorganic additives such as for example, silica, natural and synthetic silicates, Contain alumina or silicon carbide. As a particularly advantageous Electrographite and silicon dioxide have been found. All Components of the dry material mixture are ground to flour fineness, this means the grain size is maximum 500 um. A dry material mixture may, for example, from 70 to 99 Weight percent graphitized carbon black, 0 to 30 weight percent synthetically produced graphite or natural graphite and 0 to 15 Percent by weight of inorganic additives.

The dry mixture is then mixed with cokeable, organic compounds such as resins containing binders and pitches, preferably a commercially available binding pitch whose softening point according to Krämer-Sann (DIN 52025) preferably in the range of 70 to 110 ° C, and then pressed into shaped bodies. This is the Mass fraction of the binder based on the mass of the dry mixture 10 weight percent to 15 weight percent.

The thus obtained molded body can already the basic form of the desired Sliding elements or another form favorable for further processing to have. The moldings are then excluded under the exclusion of oxidizing substances in Range from 800 to 1400 ° C burned. The burnt soot coke be in turn, excluding oxidants, in addition to graphitization temperature, this means heated to temperatures of preferably 2300 to 3100 ° C.

To Cooling the body in an oxidation-inert atmosphere they become one after another known methods with at least one of the substances from the group Synthetic resins, pitches, metals or metal alloys impregnated, the impregnation with synthetic resins and / or pitch then during another firing process is pyrolyzed. Preference is given as a resin phenolic resin and as metal or alloy constituent nickel, silver, copper, antimony, aluminum or magnesium, with particular antimony being advantageous has exposed. The amount of impregnating agent used depends on the pore structure from. The goal is maximum backfilling existing pores of the sliding material.

The impregnated Parts are then required on those in use as sliding elements Finished shape and surface finish.

Of the Sliding material according to the invention thus has a structure in which the graphitized Rußkoks and if appropriate, the other synthetically produced graphite components or natural graphite portions of the dry mix in a carbonized, non-graphitic Matrix are involved, wherein the pores of the material with the Impregnating are filled. This material structure thus stands out from the usual Way burned carbon materials that are not graphitic Structure, as well as graphite materials from which a continuous possess graphitic structure.

Further Details, features and advantages of the present invention result from the following description of a particular embodiment with reference to the drawing. It shows:

1 an inventive plain bearing in section and

2 a perspective view of the in 1 shown plain bearing in exploded view.

As the figures can be seen, has a bearing sleeve 1 pointing at a dividing bolt 5 a transport chain is arranged, a collar 1b on.

The bearing sleeve 1 consists of high temperature resistant metals such as steel or non-metals such as high surface quality ceramics with a mean roughness Ra <3.2 μm.

On the bearing sleeve 1 is a roller 2 arranged, which from an inner Kohlering 2 B , which consists of a sliding material containing as an essential filler graphitized soot, whose pores are filled with metallic or non-metallic materials, and an outer steel ring 2a consists. The steel ring 2a sits with a press fit on the Kohlering 2 B ,

The wall thickness of Kohlerings 2 B corresponds approximately to the height of the collar 1b , At the collar 1b opposite side of the bearing sleeve 1 is on the bearing sleeve 1 a steel disc 3 arranged. The steel disc 3 sits essentially without play on the bearing sleeve 1 , The outer diameter of the steel disc 3 corresponds to the outer diameter of the collar 1b that is the outside diameter of the carbon ring 2 B or the inner diameter of the steel ring 2a , This is the Kohlering 2 B protected arranged in an annular groove.

The steel ring 3 has a radially extending opening 3a on. Likewise, the bearing sleeve 1 a radially extending opening 1a on. Furthermore, the dividing bolt 5 a radially extending opening 5a on. The opening 3a the steel disc 3 , the opening 1a the bearing sleeve 1 and the opening 5a of the split pin 5 correspond with each other, leaving the steel disc 3 , the bearing sleeve 1 and the split pin 5 by means of a tension pin 4 can be fixed together. This can cause the steel disc 3 not on the bearing sleeve 1 turn and the bearing sleeve 1 not on the dividing bolt 5 rotate. Only the Kohlering 2 B is rotatable on the bearing sleeve 1 or arranged in the annular groove.

The steel disc 3 is so on the bearing sleeve 1 fixed that of Kohiering 2 B essentially without axial play on the bearing sleeve 1 sitting.

The big advantage of the sliding bearing according to the invention is then that it has a long service life. Furthermore, the plain bearing according to the invention can be replaced in a simple manner. All you need is the dowel pin 4 from the openings 3a . 1a . 5a to be removed, whereupon the steel ring 3 as well as the roller 2 easily from the bearing sleeve 1 remove and the bearing sleeve 1 easily from the dividing bolt 5 can be removed. Conversely, a sliding bearing according to the invention can be easily on a dividing pin 5 Arrange. As a result, the replacement of a sliding bearing can be replaced without major interruption of operation of a baking oven.

Claims (10)

Slide bearing, in particular for a conveyor belt in an oven, with a bearing sleeve ( 1 ), on which a roller ( 2 ) is rotatably arranged, characterized in that the roller ( 2 ) a metal ring ( 2a ), in which a Kohlering ( 2 B ) is arranged. Plain bearing according to claim 1, characterized in that the wall thickness of the carbon ring ( 2 B ) is greater than the wall thickness of the metal ring ( 2a ). Plain bearing according to claim 1 or 2, characterized in that the Kohlering ( 2 B ) in one on the bearing sleeve ( 1 ) formed annular groove is arranged. Slide bearing according to claim 3, characterized in that the bearing sleeve ( 1 ) an all-round collar ( 1b ), the height of the wall thickness of Kohlerings ( 2 B ), as well as on the bearing sleeve ( 1 ) a disk ( 3 ) is arranged, the outer diameter of the outer diameter of the collar ( 1b ) corresponds. Slide bearing according to claim 4, characterized in that the disc ( 3 ) has a radially extending opening (FIG. 3a ) having. Slide bearing according to one of claims 1 to 5, characterized in that the bearing sleeve ( 1 ) has a radially extending opening (FIG. 1a ) having. Sliding bearing according to one of claims 1 to 6, characterized in that the Kohlering ( 2 B ) consists of a sliding material containing as a major filler graphitized carbon black, the pores are filled with metallic or non-metallic materials. Slide bearing according to claim 7, characterized that the sliding material graphitized soot coke with an ash content of less than 1%. Sliding bearing according to claim 7 or 8, characterized that the sliding material with nickel, silver, copper, antimony, aluminum or magnesium or alloys thereof is impregnated. Sliding bearing according to one of claims 7 to 9, characterized that the sliding material as additional Components of synthetically produced graphite or natural graphite and / or inorganic additives contains.