KR100470090B1 - Method for manufacturing friction liner, especially for crowns with dry friction clutches, and friction crowns for dry clutches for automobiles - Google Patents

Abstract

An automobile clutch friction liner or friction crown in the form of a plate-shaped ring is prepared by impregnating the yarn with rubber in a thermosetting resin base mixture of various fillers dispersed in a mixture with rubber dissolved in a solvent. The yarns consist of inorganic fiber substrates reinforced with metal, optionally including organic fibers. After impregnation, the yarns are dried and then temporarily stored in the form of coils in the vat. Subsequently, the impregnated yarn is recovered from the bin and placed in a mold in which a workpiece in the form of a plate-shaped ring is molded in a wave manner. The workpiece is then cured at elevated temperature under pressure and then trimmed to an appropriate size, forming any recesses or holes for riveting. The impregnation step in the field is carried out in a bath in which the hard solvent and the heavy solvent are combined so that the boiling point of the heavy solvent is substantially higher than the boiling point of the light solvent.

Description

Method of producing friction liner, in particular method of manufacturing crown for dry friction clutch, and friction crown for dry clutch for automobile

The present invention relates to a method for producing a friction liner, in particular a method for producing a friction crown for a dry friction clutch, ie a plate-shaped liner. The invention also relates in particular to friction crowns for dry clutches for automobiles, such as electric vehicles, luggage carriers and the like.

Processes for producing this type of friction liner are known and comprise the following steps:

Impregnating a yarn formed from an inorganic fiber substrate (and optionally also comprising organic fibers) with a metal reinforcing agent in a thermosetting resin base mixture consisting of (a) rubber dissolved in a solvent and (b) various fillers dispersed in the mixture. ;

-Drying the impregnated eye;

Temporarily storing the impregnated and dried yarn in the form of a coil in a barrel;

Forming the obtained workpiece or blank into a plate-shaped ring by recovering the impregnated yarn from the reservoir and placing it in a mold in a wave manner;

Heat treating the blank under pressure;

-Processing the plate-shaped ring obtained as above to the desired dimension; And optionally

Forming a passage and a recess of the fixing rivet head in the plate-shaped ring.

In order to produce a binding workpiece, the impregnated yarns must have a specific binding capacity. To this end, the drying step carried out after the impregnation step is incompletely carried out so that a small amount of solvent remains in the impregnated eye. However, the solvent volatilizes rapidly or slower, and it has been found that various disadvantages exist.

In this regard, the binding capacity of the impregnated eye is reduced, which is rapidly extinguished over a period of time, which means that the above mentioned temporary storage should be very short. Indeed, such storage should be less than three days in temperate climates and high altitudes, and no more than four hours in high altitude tropical climates.

The evaporation of the solvent remaining in the field after the drying step substantially changes the component ratios of the components actually used in the manufacture of the friction crown, which makes it impossible to properly perform quality control of the finished product.

In this regard, due to the uncontrolled solvent evaporation after the drying step, the amount of solvent present in the impregnated eye field when the workpiece itself is produced is variable (the amount of material introduced into the mold to produce the workpiece is constant). The amount of material remaining after the heat treatment step or heat curing step of the workpiece is variable. This not only results in nonuniform weight and quality of the workpiece, but also suppresses porosity. This in turn creates, in many cases, rejects that are returned at the end of the manufacturing process.

In addition, the above-mentioned solvents are stored in hazardous and not completely dry impregnated yarns, and the heat treatment of the workpieces requires special precautions and complicated special equipment. It also poses a health risk to the operator and the environment.

It is an object of the present invention to provide a friction liner with excellent and consistent quality; And, in particular, by overcoming the above mentioned disadvantages by presenting an environmentally friendly method for producing a friction crown for a dry friction clutch for automobiles.

According to the first aspect of the invention,

Impregnating a yarn formed from a substrate of inorganic fibers and optionally organic fibers with a metal reinforcing agent in a thermosetting resin base mixture consisting of rubber dissolved in a solvent and various fillers dispersed in the mixture;

-Drying the impregnated eye;

Temporarily storing the impregnated and dried yarn in the form of a coil in a barrel;

Forming the obtained workpiece or blank into a plate-shaped ring by recovering the impregnated yarn from the reservoir and placing it in a mold in a wave manner;

Heat treating the blank under pressure;

-Processing the plate-shaped ring obtained as above to the desired dimension; And optionally

A method of producing a friction liner, in particular a friction crown for a dry clutch, comprising forming a passage and a recess of a fixing rivet head in the plate-shaped ring. It is characterized in that it is carried out using a bath comprising a mixture of two solvents, a so-called heavy solvent, wherein the solvents have a boiling point of the heavy solvent substantially higher than that of the light solvent.

According to a preferred feature of the invention, the temperature difference between the boiling points of the two solvents is at least 60 ° C.

According to a further preferred feature of the invention, the drying step of the impregnated yarn is carried out at a temperature slightly above the boiling point of the light solvent and substantially below the boiling point of the heavy solvent.

Preferably, the boiling point of the hard solvent is 70 to 110 ° C .;

Preferably, the boiling point of the heavy solvent is from 170 to 270 ° C .;

Preferably, the weight ratio of the heavy solvent is 0.8 to 3.1% of the total amount of the solvent;

Preferably, the weight ratio of heavy solvent to rubber is 9 to 32%;

Preferably, the heavy solvent is a solvent of the plastic type;

Preferably, the heavy solvent is an ester type plasticizer;

Preferably, the heavy solvent is dioctyl adipate (diethyl-2 hexyl adipate);

Preferably, the light solvent is trichlorethylene.

Thus, in the process according to the invention, the light solvent can be removed without removing the heavy solvent during the drying step. This can have a composition that can ensure that the impregnated yarns are constant, which is a measure of the quality of the finished product.

In the process of the invention, during the storage step, generally no toxic light solvent vapors are already generated since they have already been removed. Furthermore, the vapor is removed under conditions that exclude any hazards to the environment.

Heavy solvents do not cause any significant evaporation; The environment is preserved; The impregnated yarn retains its binding capacity for a long time (may exceed 2 weeks) in any climate and altitude at which storage is performed. The storage step thus provides suitable process flexibility in the manufacture of the friction liner.

According to a second aspect of the invention, a friction liner, and in particular a friction crown for an automotive dry friction clutch, are produced by the method according to the first aspect of the invention. According to a preferred feature of the invention of this second aspect, the friction liner preferably contains a heavy solvent such as dioctyl adipate.

Surprisingly, such liners have improved friction characteristics, especially with regard to the transmission of torque, especially at the moment of engagement of the clutch. This significantly reduces the clutch snatch effect.

Further features and advantages of the invention will be more apparent from the following description of examples of preferred methods of carrying out the invention.

Various samples are prepared by impregnating a yarn having the following composition and characteristics:

TABLE 1

The impregnation is carried out in an impregnation bath having the following composition:

Solvent: 340 kg

Cement: 100 kg in total (rubber, 20 kg; phenolic resin, 25 kg; melamine resin, 24 kg; sulfur, 4 kg; zinc oxide, 1 kg; carbon black, 10 kg; lead monoxide, 11 kg; aromatic resin, 1 kg; asphalt resin, 4 kg)

For each sample, the relative weight ratio of light solvent to heavy solvent (ie solvent of plastic type) is shown in Table 2 below:

TABLE 2

The weight ratio of heavy solvent to rubber is preferably selected in the manner of Table 3 below:

TABLE 3

The boiling points of the solvent components are as follows:

Trichlorethylene: 87 ° C

Dioctyl adipate: 214 ° C

After impregnating the sample of the eye, they are dried by passing through an oven (provided with a solvent vapor recovery device) heated to a temperature of 100 to 120 ° C. The length of the drying period is preferably such that no light solvent remains anymore but a portion of the heavy solvent (0.95 to 1.6% of the total mass) remains.

After drying, the impregnated yarn is coiled into a container or pail of cardboard or cardboard. They are stored and stored in this manner until they are used for the remainder of the manufacturing process, which is finally molded into a friction liner.

It has been found that the impregnated yarns prepared in the above-described manner retain their full binding capacity for a period of at least two weeks, so that they can be stored in this way under any climatic conditions and altitudes.

It has also been found that impregnated yarns are easier to handle than impregnated yarns prepared according to the prior art (see Sample 1 above). In particular, the process of winding the yarn inside the tub for storage is quite easy. In addition, while no evaporation of solvent was detected from Samples 2-4, for Sample 1 it was necessary to seal the reservoir to reduce solvent escape to the atmosphere.

Several sets of clutch friction crowns are then made from four impregnated yarn samples made in the manner described above. To this end, workpieces or blanks are produced in the form of platelets, respectively. These plate-shaped rings are manufactured by recovering impregnated yarns from a storage container and feeding them to the mold in a wave manner. The workpiece is then cured in a mold at 130 ° C. under a pressure of 300 bar and then heat treated. Subsequently, the workpiece is trimmed or processed to the required dimensions.

The clutch friction crown obtained in this manner is then fixed on a metal disk to assemble the dry friction clutch wheel. This fixing is carried out by adhesive bonding and / or riveting. In the case of the rivet seam, the clutch friction crown is drilled or penetrated to form a hole for receiving the base of the rivet together with a wider recess for accommodating the rivet head.

While fabricating the clutch friction crown from Samples 2-4 described above, it was found that there was a significant return reduction at the end of the fabrication process compared to the prior art method illustrated by Sample 1 above. This has actually been found to be reduced fourfold, and there are several reasons for this improvement.

The first reason for this is that the workpiece forming machine, as observed, works much better without particular jams. A further reason is that the workpiece has improved geometric integrity, which is almost constant from one workpiece to the other, resulting from the improvement and consistency of the binding capacity of the impregnated yarn.

The occurrence of returns, which often occur after the curing process, in existing known methods is also eliminated. In this regard, due to the careful control of the components used to mold the workpieces in the process according to the invention, and in particular the proportion of solvents (i.e. heavy solvents) in the impregnated yarns, Porosity is suppressed and only changes within a very narrow range.

It has also been surprisingly found in the method of the present invention that the transmission of torque by the clutch with said friction crown is significantly improved at the moment the clutch is engaged. Clutch quick engagement effects that tend to occur during the clutch engagement process are reduced by this and may even be eliminated. This is believed to be due to the improved uniformity of the friction liner, which is due to the improvement and stability of the binding capacity of the impregnated yarn, with the presence of heavy solvents in the liner. The heavy solvent is preferably dioctyl adipate.

Table 4 below shows the results of various tests and experiments performed on the four impregnated eye samples described above. Sample 1 represents a conventional one.

TABLE 4

In general, it was found that the best results were obtained when the relative ratios of heavy and light solvents were as described above for Samples 2 and 4.

The present invention provides a friction liner with excellent and consistent quality in an environmentally friendly manufacturing method using a bath comprising a solvent mixture of a heavy solvent and a hard solvent and a friction crown for a particularly dry friction clutch for automobiles.

Claims (13)

Impregnating a yarn formed from a substrate of inorganic fibers and optionally organic fibers and having a metal reinforcing agent in a thermosetting resin base mixture consisting of rubber dissolved in a solvent and various fillers dispersed in the mixture; -Drying the impregnated eye; Temporarily storing the impregnated and dried yarn in the form of a coil in a barrel; Forming the obtained workpiece or blank into a plate-shaped ring by recovering the impregnated yarn from the storage container and placing it in a mold in a wave manner; Heat treating the blank under pressure; Processing the obtained plate-shaped ring into the desired dimensions; And optionally Forming a passage and a recess in the plate-shaped ring for the fixing rivet head, The impregnation step of the eye is a bath comprising a mixture of a light solvent as a first solvent and a heavy solvent as a second solvent, wherein the boiling point of the heavy solvent is substantially higher than that of the light solvent. Method for producing a friction liner, in particular a friction crown for a dry clutch, characterized in that carried out using. The method of claim 1, The temperature difference between the boiling point is characterized in that more than 60 ℃. The method of claim 1, Wherein the drying step of the impregnated yarn is carried out at a temperature slightly above the boiling point of the light solvent and substantially below the boiling point of the heavy solvent. The method of claim 1, The boiling point range of the hard solvent is 70 to 110 ℃. The method of claim 1, The boiling point range of the heavy solvent is 170 to 270 ℃. The method of claim 1, The weight ratio of the heavy solvent is in the range of 0.8 to 3.1% of the total amount of solvent. The method of claim 1, The weight ratio of heavy solvent to rubber is 9 to 32%. The method of claim 1, Wherein the heavy solvent is a plastic type solvent. The method of claim 1, Wherein the heavy solvent is an ester type plasticizer. The method of claim 1, Wherein the heavy solvent is dioctyl adipate (diethyl-2 hexyl adipate). The method of claim 1, Wherein the light solvent is trichlorethylene. A friction liner, in particular a friction crown for an automotive dry clutch, characterized in that it is produced by a method according to any of the preceding claims. The method of claim 12, A liner characterized by containing a heavy solvent, preferably dioctyl-adipate.