DE3104515A1 - "FRICTION ELEMENT, IN PARTICULAR BRAKE PAD" - Google Patents

Description

The present invention relates to a friction element, in particular a brake pad that is attached to a moving web-forming counter material can be brought into contact with friction, in particular on a brake disc, a Brake rim, a brake tire or a brake drum, with a carrier that cooperates with an actuating device capable of, and a friction lining that is applied to the carrier as a function of the actuating device Force can be pressed onto the web with an attack surface, the force being converted into a pressure distribution above the attack surface.

In general, a rolled, i.e. constant-thickness, metal carrier is used as the carrier. This results in a pressure along the contact surface of the friction lining on the web, which in its entirety may be useful, but not necessarily one that is optimally desirable in the intended application Pressure distribution corresponds, or even in certain applications to irregularities in the Puncture and a risk of deformation can give rise.

130049/0633

(only PA Dipl.-Ing.S. Staeger)

Furthermore, the wear is not uniform, but rather at j

the j located "upstream" with respect to the direction of rotation of the disk

Reinforced outer end of the brake pad. This leads to the fact that ί

the abraded brake pad at this end has a bevel!

shows, who trains independently, and who from a certain point:

Wear condition to a less than satisfactory puncture- ■

ren leads. j

It has been found by the applicant that the thickness of the carrier has an influence on the pressure distribution along, i.e. across the contact surface of the friction lining on the web, and that even over the extent of this contact surface a real assignment exists between the thickness of the support at one point on the one hand and the pressure applied at that point on the other.

The present invention is based on the object of providing a friction element, in particular to specify a brake pad that rubbing against a mating material forming a moving path to abut can be brought, in particular on a brake disc, a brake rim, a brake tire or a brake drum, which does not have the disadvantages explained above and which is characterized by excellent operating conditions, but is nonetheless characterized by a simple and convenient structure.

Starting from a friction element of the type explained at the beginning, this object is achieved in that the thickness of the carrier is designed so progressively variable that the distribution of the pressures over the attack surface with a previously selected Distribution matches.

Thanks to this configuration, it is possible in a simple manner by suitably varying the carrier thickness along the contact surface of the friction lining on the web achieve a pressure distribution that is an optimal distribution for an intended application corresponds, for example, to a uniform distribution and

130049/0633

if necessary a corrected distribution to a beveled Avoid abrasion at the "upstream" end.

In one embodiment of the invention is the thickness of the carrier in the area where the actuating device acts on the carrier, so less that the pressure distribution over the contact surface is exactly uniform, while in a modified form the thickness of the carrier in the direction of movement of the Web (downstream) lying area is formed so stronger that in the pressure distribution over the attack surface in the A stronger pressure occurs in order to avoid the wear of the friction lining in the upstream area increasingly appears. Incidentally, these two configurations can advantageously be combined with one another.

According to a further embodiment of the invention, the fluctuations in the strength of the carrier take place progressively such that Abrupt jumps in the pressure distribution over the attack surface can be avoided.

According to a further development of the invention, the carrier consists of a composite material which, in particular, has fabric layers, for example glass fabric, the number of superimposed layers being variable depending on the carrier area; the Fabric layers are impregnated with a binding agent, in particular with phenolic resin. With this measure you can easily Way to get varying carrier thicknesses. In addition, the block formed in this way is characterized by soft, noiseless and effective functionality, has good thermal insulation and is extremely corrosion-resistant.

The friction lining preferably consists of the same material as the carrier Compatible material and has a binder formed from a formophenolic resin, fibers and fillers.

According to a further development of the invention, the carrier has ribs which define the fluctuations in the carrier thickness.

130CU9 / 0633

The ribs can have any suitable configuration, for example they can be arranged in a cross shape and reinforce the strength of the beam, while at the same time making it possible to easily obtain the preselected pressure distributions.

It is advantageous if the ribs are arranged towards the friction lining in such a way that the outside of the carrier is exactly flat.

Reinforcements are preferably included in the ribs. These reinforcements can have any suitable cross-section, for example they can be round or oblique. These reinforcements can in particular consist of a steel wire or a carbon wire or from wire of any other suitable material.

The ribs advantageously extend in the vicinity that area where the actuating device engages the carrier.

In the following the invention is explained in more detail on the basis of exemplary embodiments with reference to the drawings.

Show it:

Figure 1 is a perspective partial view of a disc brake with a friction element according to the invention ,

Figure 2 is a partial cross-sectional view of the brake according to

Fig. 1 on an enlarged scale according to the section line II-II shown in Fig. 3,

Figure 3 is a sectional view along the line III-III in

Fig. 2,

Figure ² J a horizontal sectional view according to the line

130 0 49/0633

Figure 4A

Figure 5

Figure 6

Figure 7

IV-IV in Fig. 3 of the brake pad with illustrated pressure distribution, which according to the in Figures 1 to cases shown is uniform due to a correspondingly changing thickness of the carrier,

a view corresponding to figure k with a pressure distribution which results when the carrier is designed in a conventional manner with constant thickness,

a modified embodiment in which the The thickness of the support changes so that the pressure distribution allows a bevel avoid causing wear on one of the ends of the brake pad,

a sectional view along the line VI-VI in Fig. 7j the another variant of the invention Friction element shows

a plan view of a single carrier of the last-mentioned variant corresponding to the view in the direction of arrows VII-VII in Fig. 6,

Figure 8

Figure 9

Figure 10

a further embodiment in which the ribs of the carrier of the friction element are reinforced absorb

a representation corresponding to the representation according to FIG. 8 of a further embodiment,

a representation corresponding to FIG. 6 of a further variant of the friction element according to the invention, the section being selected along the line X-X in FIG. 11, and

13004 9/0633

FIG. 11 shows a plan view of the carrier of the last-mentioned embodiment shown in detail, the top view being in the direction of the arrows XI-XI in FIG.

The embodiment of the invention shown in FIGS relates to a disc brake for a motor vehicle, but this is merely a non-limitation significant example. The disc brake has a rotating disc 10 (Figures 1 and 2), the two opposing each other Friction tracks 11 forms. With each track 11, a brake pad 12 works together by friction. The brake pad 12 has a carrier 13 cooperating with an actuating device C and a friction lining 14 carried by the carrier 13. In In the example shown, the blocks 12 and the devices associated with them are designed symmetrically with respect to the disk 10. By means of a mounting arrangement, each brake pad 12 is held against the associated track 11 while it is is possible to approach the path 'and he according to the in the Figures 2 and 3 illustrated embodiment has a fixed seat 16 in which it is received. The recording 16 forms side openings A and B to absorb the counter pressure the braking.

The actuator C of each brake pad 12 has a Hollow piston 15 which is subjected to hydraulic pressure in order to load the brake pad 12 in the direction of the track 11. In FIGS. 2 to 4, the reference numeral 17 indicates the annular area in which the carrier 11 is separated from the actuating piston 15 is attacked. The friction lining 14 of each brake pad 12 is designed in such a way that it is responsive to the force exerted by the piston 15 on the carrier 13 in the region 17 along, i.e., is pressed against the web 11 with an attack surface 18, the force being converted into a distribution R of pressures P over the contact surface 18. In FIG. 4, R forms a line which represents the distribution of the pressures P.

130049/0633

- ίο -

At the moment of braking, that caused by the braking Counterforce absorbed by the area A when the disc 10 rotates in the sense of a forward movement, which by the arrow P is indicated (Figure 3 and 4), the counterforce is absorbed by the area B when the disk is in the sense rotates backwards.

The thickness, or strength, of the carrier 13 is so progressive designed variable so that the distribution R of the pressures P over the attack surface 18 corresponds to a previously selected distribution. In the example shown in Figures 1 to 4, the strength of the support 13 in the area 17 where the actuating device 15 acts on the carrier 13, less than in the other areas where the thickness E is found. The different The thickness is chosen such that the distribution R of the pressures P over the contact surface 18 is exactly uniform (FIG 4). It can also be seen from FIG. 4 that the fluctuations in the thickness between the value e and the value E run in such a way that that the thickness of the carrier 13 has no abrupt transitions.

In the embodiment shown in Figures 1 to 4, the carrier 13 consists of a composite material with glass fabric layers, which are superimposed in such a number that the number is variable according to the area of the carrier, and the glass fabric layers are impregnated by means of a binder formed from phenolic resin, while the friction lining 14 is made of a material compatible with the material of the carrier 13 and a binder composed of a formophenol resin, Consists of fibers and fillers.

Examples of the manufacture of the brake pad 12 are given below, but they are not of any limiting importance:

130049/0633

EXAMPLE 1

~ AA-

A sufficient number of pre-cut layers of a glass fabric pre-impregnated with phenolic resin is layered. This number fluctuates between the individual areas of the surface of the carrier 13 with a view to achieving the in the figures and 4 shown structure.

The carrier assembled in this way is cooked in a form whose shape corresponds to the layering described above, for a period of 15 minutes at 170 ° C. at a pressure of 20 bar.

The surface of the carrier 13 facing the friction lining lh is poured with a phenolic resin adhesive.

This coated carrier is covered with a friction material composed of the following volume proportions:

Formophenolic resin 10 to 15

Mineral fibers (basalt) 0 to 55

Asbestos fibers 0 to 55

organic filler that goes through

Condensation of cashew nut liquid

xeit is obtained from 0 to 15

Carbon black 2 to 7

Paryt 3 to 25

Mud chalk 2 to 20

Zircon 1 to 5

Copper powder 0 to 15

The mixture having the composition given above, which forms the friction material of the friction lining Ik , is tabletted under a pressure of 150 bar. This tabletted mixture is then applied to the carrier 13 for 8 minutes at a temperature of 145 ° C. and a pressure of 375 bar.

130049/0633

- 12 EXAMPLE 2

It is put into a form customary in powder metallurgy, which allows the formation of a workpiece with two cross-sections, a friction material that forms the lining 14 and the composition of which has the following proportions by volume:

CNSL modified formophenol resin for
Friction elements 10 to 35

Styrene-butadiene rubber 5 to 15

Sulfur 0.5 to 3

Slag mineral fibers 15 to 40

Metal fibers 0 to 40

Asbestos fibers 0 to 45

organic fibers 0 to 15

crumbled brass wool 1 to 10

Tin powder 0.5 to 4

Black lead 5 to 15

Antimony sulfide 1 to 7

Barite 10 to 25

Magnesia 1 to 10

Silica 2 to 10

Graphite 3 to 8

Wood flour 2 to 7

This mixture is tabletted under a pressure of 70 bar to maintain the desired relief, which is shown in FIG.

ρ Then you put two layers of glass fabric with each 325 g / m. , pre-impregnated with phenolic resin. Phenolic resin is added, which is enriched to 35 vol. Si with glass fibers of 6 mm is. A glass fiber mat pre-impregnated with phenolic resin is added

2
of 300 g / m. Then cook the whole thing for 10 minutes

a temperature of 150 ° C and a pressure of 250 bar.

It should be noted that the carrier is either a glass fabric, a
Glass fiber mat, a mixture of pieces of glass fiber or combined

130049/0633

may have these components in whole or in part. EXAMPLE 3

Proceed as in Example 1 or Example 2, but also use reinforcement (e.g. made of wire mesh) in the vicinity of the brake lining and at a distance of about 1 mm from it into the carrier. This wire mesh is used for advantageous Stiffening of the beam.

EXAMPLE H

The procedure is as in Example 1 or in Example 2 and optionally as in example 3, but a very hard insert is added which exactly matches the shape of the contact area 17 of the actuating device C and is arranged in the immediate vicinity of this area in order to calk avoid.

The block 12 thus produced according to Examples 1 to 4 has the shape shown in Figures 2 and h , where you can see the carrier 13 and the friction lining Ik and where you can see that the thickness of the carrier 13 varies, with a reduced thickness e is present at the point 17 attacked by the hollow piston 15, while a greater thickness E is provided in other areas.

With a plate 12 designed in this way, a distribution is obtained R of the pressures P, which is exactly uniform, whereby excellent operation of this brake pad 12 is possible.

FIG. 4A shows the distribution RA of the pressures PA which would result if the carrier 13A had a constant strength, as is customary. In this case, the distribution of the pressures PA RA is not uniform, but the distribution varies as shown in Figure ¹ IA, causing imbalances in the operation and the risk arising deformation.

13 0049/063 3

Figure 5 shows a modified embodiment. The embodiment shown in FIG. 5 is analogous to the embodiment described with reference to FIGS. 1 to 4, and the same reference symbols are used, only that the reference symbols are now deleted. The thickness of the carrier 13 is made variable in such a way that the distribution R 'of the pressures P ^T along the surface 18' coincides with a previously selected distribution. In the example shown in FIG. 5, the thickness of the carrier at E ¹ in the area of the block 12 downstream with respect to the direction of movement F of the web 11 is greater than in the upstream area where the thickness is indicated by e ¹ . In this way, the distribution R ^{T of} the pressures P * over the contact surface 18 'in the downstream area makes the pressures stronger, in order to prevent the wear of the friction lining 14' in the "upstream" area from appearing in the form of a bevel occurs.

It should be emphasized that the embodiment according to Figure 4 and that can advantageously be combined according to Figure 5, and that in such a case the strength of the carrier so variable is designed so that the fluctuations in the thickness according to FIG. 4 combine with those according to FIG. 5 in such a way that a pressure distribution which is also as uniform as possible, but at the same time a correction for the tendency creates that the abrasion in the "upstream" area of the block 12 comes to light in the form of a bevel.

As far as the wear of the friction lining is concerned, it does not matter that the carrier is at least partially in frictional contact with the disk 10 comes, provided that the carrier due to its special nature does not run the risk of damage is exposed.

Figures 6 and 7 show a further embodiment of the friction element according to the invention, which is there as a brake pad 12 ' is designed for a disc brake.

130049/0633

The block 12 ″ has a carrier 13 ″ which interacts with an actuating device via a hollow piston 15 ″. The block 12 'also has a friction lining 11 carried by the carrier 13'' ^! " on.

As in the exemplary embodiment shown in FIGS. 1 to 4 or in FIG. 5, the thickness of the carrier 13 ' ^{f is designed to be} variable in such a way that the distribution R ^{11 of} the pressures P ¹¹ over the contact surface 18 of the friction lining is selected in advance Distribution matches.

According to FIGS. 6 and 7, the changing thickness of the carrier 13 ″ is implemented by ribs 20 of the carrier 13 ^fl . These ribs 20 are formed on the ^{side facing the friction lining 14 ff in} such a way that the outer surface 21 of the carrier 13 "is exactly flat. The ribs 20 extend in the vicinity of the annular region 17", where the actuating device 15 "on the Attacks carrier 13 ''.

In the exemplary embodiment shown in FIG. 7, the ribs 20 specifically have a cruciform distribution through which the area 17 ″ is surrounded.

Like ι. 3i the embodiment according to Figures 1 to 4 consists the carrier 13 ″ preferably made of a composite material with superimposed Glass fabric layers, which are impregnated with a binder made of phenolic resin, during the friction lining 14 '"made of material compatible with the material of the carrier 13" and has a binder made of formophenol resin, Fibers and fillers is formed.

While in the embodiment according to Figures Ibis 4 the The changing thickness of the carrier 13 ″ is specifically implemented by a changing number of glass fabric layers In this exemplary embodiment, ribs 20 are realized by folding the glass fabric layers.

130049/0633

As a modified embodiment (Figure 8) analogous to the one just now The embodiment explained with reference to FIGS is included. The reinforcement 22 can be a steel wire, a carbon thread or a wire act on any other material. In the exemplary embodiment shown in FIG. 8, the reinforcement 22 has a circular shape Cross-section, but any other suitable cross-section can also be provided, for example a cut one Cross-sectional shape as shown in FIG. However, these examples are not in any way limiting.

The embodiment illustrated in Figures 11 and 12 is ^f analogous to the above with reference to Figures 6 and illustrated embodiment 7, it can be seen at ^{13! L} the carrier and IA '' ¹ the brake lining desBremsklotzes 12 ^'11, the ribs 20 however, have a configuration that differs from the exemplary embodiment according to the FIGURE.

^{According to FIGS} . 10 and 11, the ribs 20 follow a first ring 23 inside the area 17 lft, a second ring 24 outside the area 17 ' ^ft and diagonal sections 25 that connect the outer ring 2h with the four corner points 26 of the support 13' ^ft of the brake pad 12 '". FIG. 10 shows the distribution R ^{IM of} the pressures ρ' · 'along the contact surface 18 ^IIT .

The present invention is not limited to the embodiments explained above limited, but numerous modifications are still possible without departing from the basic concept of the invention is deviated, provided that the progressive changes in thickness of the carrier are chosen so that a pressure distribution is obtained which corresponds to a preselected distribution.

130049/0633

Claims (16)

PATENT CLAIMS ( 1. j friction element, in particular brake pad, which can be brought into contact with friction on a counter material forming a moving path, in particular on a brake disc, a brake rim, a brake tire or a brake drum, with a carrier that is able to interact with an actuating device , and a friction lining which, depending on a force applied by the actuating device to the carrier, can be pressed onto the web with an application surface, the force being converted into a pressure distribution over the application surface, characterized in that, that the thickness of the carrier (13,13 *, 13 * ', 13 ¹ ") is designed to be progressively variable in such a way that the distribution (R ₉ RSR ¹ SR" ¹ ) of the pressures over the contact surface (18, 18 ·, 18' ·, 18 '') matches a pre-selected distribution. 130049/0633 (only PA Dipl.-Ing.S. Staeger) 2. Friction element according to claim 1, characterized in that the thickness (e) of the carrier (.13) in the area (17) where the actuating device engages the carrier (13) is so smaller that the pressure distribution (R) is exactly uniform over the attack surface (18). 3. Friction element according to claim 1 or 2, characterized in that the thickness (E) of the carrier (13 ¹ ) in the area lying in the direction of movement of the web CH) (downstream) is formed so stronger that in the pressure distribution (R ¹ ) Stronger pressures occur above the contact surface (18 *) in the area mentioned in order to avoid the wear of the friction lining emerging as a bevel in the upstream area (FIG. 5). 4. friction element according to one of the preceding claims, in which the carrier consists of a composite material, characterized in that the carrier comprises a base material, the thickness of which varies along the region of the carrier, and which is impregnated with a binder. 5. Friction element according to claim 4, characterized in that the base material is glass, while the binder is phenolic resin. 6. Friction element according to claim 5 » characterized in that the base material consists of a glass fabric arranged in superimposed layers, the number of layers being variable according to the area of the carrier. 7. friction element according to claim 5 » characterized in that the base material has a glass fiber mat. 8. Friction element according to claim 5 » characterized in that the base material has a mixture of pieces of glass fiber. 130049/0633 9 · Friction element according to claim 5, characterized in that
that the basic material simultaneously in its entirety or
partially comprises a glass fabric, a glass mat and a mixture of glass fibers. 10. Friction element according to one of claims k to 9 » characterized by drawing t, that the friction lining made of a compatible with the material of the carrier Consists of material and has a binder which is formed from a formophenol resin, fibers and fillers, 11. Friction element according to claim 10, characterized in that that a phenolic resin adhesive is provided between the carrier and the friction lining. 12. Friction element according to one of claims h to 11, characterized in that the existing carrier and friction lining
Arrangement is subjected to pressure cooking. 13. Friction element according to one of the preceding claims, characterized in that the carrier (13 ", 13 '") has ribs (20) (Figures 6 to 10). 14. Friction element according to claim 13, characterized in that
that the ribs (20) are located on the side of the friction lining (I4 ", l4" ^f ). 15. Friction element according to claim 13 or l * t, characterized in that reinforcements (22) are included in the ribs (20)
are (Figures 8 and 9). 16. Friction element according to one of claims 13 to 15 » characterized in that that the ribs (20) are arranged adjacent to the area (17 ", 17 ¹¹ M, where the actuating device (15 ' ¹ JlS ¹¹ ') engages the T-arm (.13", 13 ". '). 130049/0633