DE4006732A1 - Thermoplastic lubrication pipe used in central lubrication units - comprising two layers each of similar thermoplastic material with interposition of co:extrudable joining agent - Google Patents

Abstract

A lubrication pipe is made of a thermoplastic material and is prefilled with a viscous or consistent lubricant, based on mineral oil, synthetic or partially synthetic viscous lubricants, and additionally metallic soap thickeners and additives. The pipe (2) filled with lubricant (1) has two layers (3,4) each of similar thermoplastic material with simultaneous interposition of a coextrudable joining agent which are uniformally bonded by coextrusion. USE/ADVANTAGE - The pipe is used for lubrication pipes and main pipes of central lubrication units of vehicles according to DIN 75 203. Mfr. of the pipe is inexpensive.

Description

The invention relates to lubrication line pipes made of thermoplastic Plastics, e.g. B. for main and lubrication point lines from automatic central lubrication systems on motor vehicles according to DIN 75 203, with consistent or viscous lubricants filled and made up of at least two layers that for their part are integrally connected.

Lubricant-filled lubrication pipes made of thermoplastic Plastics, e.g. B. from single-layer polyamide tubes made of PA11 or PA12 according to DIN 73 378, prefilled especially with consi constant lubricants, e.g. B. Liquid greases of NLGI class 000 to 00 according to DIN 51 818 based on mineral oil, have opted for Main pipes, even with full use of the pipes permissible operating pressures and temperatures, as well as for the Lubrication point lines of automatic central lubrication systems of commercial vehicles in practical continuous use for years proven; they provide a reliable, easy to install and inexpensive conduit for central lubrication systems Consumption lubrication (see also DIN 24 271). The assignment the lubrication point lines to the single-line, multi-line or progressive systems is in the nominal range  knife DN = 1.5 to 3.5 mm, for main lines to the inlet line or progressive systems in the nominal range knife DN = 3.5 to 8 mm; Added to this is the consistency of the Lubricants, resulting in the working pressures in the Plants and the mode of action due to their construction.

Based on this known prior art Invention the task of creating lubrication line pipes fen, which are even cheaper to manufacture than that previous, without any loss of performance or quality. An additional requirement is the environmental impact during use to reduce such systems and this also applies to lubrication lines corresponding to the pre-filled lubricants to consider. These requirements are met by following measures.

The tube is made of two layers in the extrusion process of the coextru sion at the same time in one work step in plasticized Condition of both similar materials, cohesive unit Lich manufactured; due to this working process and the chemical relationship of the materials creates an intimate material bond in the entire contact area of both Materials. Here is a for the thick-walled inner layer inexpensive material quality used, e.g. B. polyamide 6 or 66. This has the disadvantage of a for the intended application Risk of stress corrosion cracking, e.g. B. due to road salt influence in connection with galvanized connection fittings of the pipes. A necessary and sufficient protection is achieved that a thin outer layer of about 0.1 mm wall thickness Polyamide 11 or 12 is applied that is not stress cracking is vulnerable; from which incidentally the one used today layered lubrication line pipes and other safety lines, e.g. B. those that carry fuel exist. In cases where different or similar  Material that is caused by chemical-physical effects in the In terms of coextrusion is diverse (e.g. Regrind), can also be coextruded at the same time thin layer of a coextrudable coupling agent between be switched, which in turn the two starting materials integrally connected with each other. The effect of the bonding agent is wetting around the surface chip reduce both materials and, due to in particular chemical reaction, on both sides with the materials in the surface layer, an intimate material bond to manufacture.

The environmental impact can, in addition to a fundamental reduction the amount of lubricant per friction point and per unit of time or per Dosage in the sense of minimum quantity lubrication, only here be reduced by such lubricants that are biological are degradable. Today's mineral oil based lubricants do not meet these requirements; come into question natural vegetable oils or synthetic lubricants, as well certain combinations (e.g. rapeseed oil - diester) for the base oils, as far as they are chemically compatible with each other. Similar Requirements apply analogously to the soap thickener as well optional for the additives.

The following substance classes of biodegradable components and their combinations of consistent lubricants with a mass fraction of X% are suitable for the
Base oils (80-90%)

• - diester oils (carboxylic acid esters),
• - vegetable oils (e.g. rapeseed oil),
• - diester / vegetable oils,
• - glycols (higher ethylene oxide content);

while the diester, plant and u. U. mineral oils are otherwise compatible, this is not the case with glycols; these represent a separate class of substances.  

Soap thickener (5-15%)

• - lithium anion,
• - calcium anion,
• - calcium lithium anion,
• - sodium anion;

it is the hydroxides of these metals with long chained vegetable animal fats (e.g. castor oil or tallow) or their hydrogenations (e.g. 12-hydroxystearate from ricinoleic acid). While lithium is compatible with calcium and thus also in their end products as different con persistent lubricants are miscible, this applies to sodium not to.

Additives (0-5%; optional)

• - containing sulfur,
• - contains phosphorus,
• - nitrogenous;

as organic compounds, e.g. B. for wear-reducing Extreme pressure active ingredients (heavy metal and / or halogen containing Connections are not permitted for environmental reasons).

• - fatty acids;
  e.g. B. as corrosion inhibitors.

The same applies to the base oils and additives for the viscous (liquid) Lubricants.

This task is solved with the characteristics the labeling part of claim 1.

Two embodiments of the invention are described below the drawing described in detail; show it

Fig. 1, the two-layer pre-filled with grease tube in a longitudinal section;

Figure 2 shows the two-layer pipe pre-filled with grease and provided with a braid layer; in the upper projection in a longitudinal section, in the lower one in a view of the inner layer and the braid layer (without outer layer).

In Fig. 1, the lubrication pipe is marked with ( 2 ); it contains the lubricant ( 1 ). The inner layer of the tube ( 2 ) is ( 3 ), the outer layer ( 4 ). The inner diameter DN of the tube ( 2 ) is ( 6 ); this is matched to the purpose and mode of action of the respective central lubrication system.

In FIG. 2, in addition to FIG. 1, a braid layer ( 5 ) is also detected, which increases the compressive strength of the tube ( 2 ); it is particularly suitable for systems with higher working pressures, e.g. B. required according to the mode of action of the progressive system.

Further different embodiments, which are not claimed in detail, are characterized by the following features (based on FIG. 1):

Form 1 The multilayer pipe ( 2 ) made of thermoplastic is cross-linked (chemically or radiation-cross-linked).

Form 2 The multilayer pipe ( 2 ) consists of thermoplastic olefins.

Form 3 The thickener of the biodegradable consistent Lubricants consist of biodegradable organo phile clays (bentonite, hectorite, baragel fats).

Form 4 The thickener of the biodegradable consistent Lubricants consist of biodegradable organic Polyureas or substituted polyureas (Polyurea, polyurea fats).  

Form 5 The thickener of the biodegradable consistent Lubricants consist of biologically compatible inorganic highly disperse silicas (gel, silica gel Fats).

Form 6 The additives of the biodegradable consistent Lubricants consist of biodegradable orga African EP active ingredients containing more sulfur and nitrogen Compounds (e.g. di-mercapto-thio-diazole derivatives) or sulfur-phosphorus compounds and ge sulfurized fatty oils (esters of fatty acids), sulfurized Esters or sulfurized alcohols or mixtures thereof plus - as corrosion inhibitors - calcium sulfonates or aminic compounds plus - as oxidations inhibitors lowest possible mass fraction - phenolic or amine compounds, all of the sulfur content is less than 20 percent by mass.

Form 7 The molecules of the polyglycols (also referred to as polyether oils or polyalkylene glycols) are constructed in the polymerization process so that their long-chain structures contain higher proportions by mass (<30%) of ethylene oxide (-O-CH ₂ -CH ₂ -) _n ; this way they become miscible with water, the natural resistance to oxidation is increased, the friction and wear behavior - due to their polar character - is extremely stable. This leads to a significantly lower level of additives (e.g. sulfur-containing compounds), optionally zero. Lithium, calcium and calcium-lithium anions can also be used as soap thickeners.

Reference numerals

1 lubricant
2 pre-filled pipe
3 inner layer
4 outer layer
5 braid
6 diameter DN

Claims (9)

1. Lubrication pipe for lubrication point and main lines of central lubrication systems made of thermoplastic, which is pre-filled with a viscous or consistent lubricant that is based on mineral oil, synthetic or partially synthetic of the viscous lubricating oil or - for consistent lubricants - additionally with metal soaps and thicker Additives is built up, characterized in that the tube ( 2 ) pre-filled with lubricant ( 1 ) consists of at least two layers ( 3 , 4 ) each of a similar thermoplastic or a different thermoplastic with the interposition of a co-extrudable binding agent, which is integrally uniform are interconnected by the coextrusion process. 2. Lubrication pipe according to claim 1, characterized in that the inner layer ( 3 ) and the outer layer ( 4 ) each consist of polyamide. 3. lubrication pipe according to one or more of claims 1 and 2, characterized in that the inner layer ( 3 ) made of polyamide 6 or 66, the outer layer ( 4 ) consists of polyamide 11 or 12. 4. lubrication pipe according to one or more of claims 1 to 3, characterized in that the wall thickness (SI) of the inner layer ( 3 ) is substantially greater than the wall thickness (SA) of the outer layer ( 4 ) with 4 ≦ SI / SA ≦ 20th is. 5. lubrication pipe according to one or more of claims 1 to 4, characterized in that between the inner layer ( 3 ) and the outer layer ( 4 ) a braided layer ( 5 ) is arranged, which consists of a plastic monofilament or yarn . 6. Lube line pipe according to one or more of claims 1 to 5, characterized in that the tube ( 2 ) in the diameter range 1.5 ≦ DN ≦ 3.5 mm of the inner diameter ( 6 ) of the inner layer ( 3 ) for lubrication point lines of central lubrication systems is trained with the design features of the single-line, multi-line or progressive system. 7. lubrication pipe according to one or more of claims 1 to 6, characterized in that the tube ( 2 ) in the diameter range 3.5 ≦ DN ≦ 8 mm of the inner diameter ( 6 ) of the inner layer ( 3 ) for main lines of central lubrication systems with the constructive features of the introductory or progressive system. 8. Lubrication pipe according to one or more of claims 1 to 7, characterized in that the tube ( 2 ) with the pre-filled, consistent and biodegradable lubricant ( 1 ), which is made of biodegradable base oils based on diesters, vegetable oils or diester Vegetable oils in connection with lithium, calcium, lithium-calcium soap thickeners or on the basis of polyglycols in connection with a sodium soap thickener and optionally with one or more biodegradable additives as organic sulfur, nitrogen or phosphorus compounds or their combinations combined with sulfurized fatty oils, sulfurized esters or sulfurized alcohols or their mixtures, forms a product unit. 9. lubrication pipe according to one or more of the claims 1 to 8, characterized in that the biodegradable additives are absolutely free of heavy metals and / or halogens and their derivatives.