DE10154334B4 - wheel brake - Google Patents

Abstract

Wheel brake, comprising
A brake body rotating with the wheel (3), in particular a brake disc (1), with a disc lining (21),
- At least one not with the wheel (3) co-rotating, pressed against the brake body, brake pad (2) with a on its back plate (23) held block lining (22), wherein
The block lining (22) comprises ceramic material,
characterized in that
- The disc covering (21) consists of opposite the pad pad (22) softer materials, and
- The disc covering (21) on each side of a plurality of segments (6a, 6b) consists.

Description

I. Field of application

The The invention relates to wheel brakes, especially disc brakes for road and rail vehicles as well as the landing gear of aircraft.

II. Technical background

to Simplification is referred to below exclusively by disc brakes, without limiting the invention to this, since all put forward here solutions Also applicable to drum brakes and other forms of wheel brakes. The invention is directed to such wheel brakes, in which as at least a part of the friction pair of the brake so-called ceramic Material is used.

When Ceramic material in the present application is a material which defines carbides and / or nitrides, in particular silicon carbide or silicon nitride and / or where fillers, in particular carbides, in a matrix of carbon, in particular in the form of carbon fibers.

conventional Disc brakes previously consisted of a brake disc made of metal, especially gray iron, Aluminum or steel, against which a brake pad with a brake pad pressed has been. Such a brake pad, a so-called "organic brake pad", consists of a Mixture containing organic components (e.g., resins, rubber), in particular in the form of organic fibers (eg aramid fibers), inorganic constituents, in particular metals and metal compounds, in particular in the form of fibers (eg mineral fibers, steel fibers, glass fibers, Ceramic fibers), fillers, Friction adjuvants (eg, graphite or barium sulfate) and / or Binders, in particular resins, in particular Fenol resin contains. Examples for organic fillers are styrene butadiene rubber, acrylonitrile butadiene rubber, Urethane rubber, ethylene-propylene rubber, Isoprene rubber, silicone rubber or other unvulcanized Rubber.

There in these friction pairings at a z. B. passenger cars no Life was achievable, where at least the harder part the friction pair, in this case, the brake disc made of metal, the Lifespan of the motor vehicle reached, and the brake pad still much more often had to be changed, other friction pairings were developed.

So Wheel brakes are already known in which the brake disc as a whole made of ceramic material, and the pad lining of the brake pad either also had ceramic material as a friction lining or the usual, only slightly modified in their composition, previously mentioned organic Brake pads like with metal brake discs.

there was in place of the above-described ceramic material initially only Carbon, in particular reinforced with a proportion of carbon fibers, eg. As carbon cloth, used with a binder, usually a phenolic or epoxy resin, offset and compressed and cured has been. Thereafter, the carbonization and graphitization of the compact, usually several times in succession to achieve a corresponding density, followed by the mechanical processing of the material.

This Carbon fiber reinforced Carbon (CFC) is still used today in racing cars of the formula 1 and the wheel brakes on aircraft both for the brake disc and used as a brake pad lining. The advantages of low weight and the high braking performance but with the disadvantages a short service life due to high abrasion, poor wet braking behavior and an oxidative combustion in air at temperatures from about 480 ° C.

By Storing a carbide or nitride, in particular a silicon carbide (SiC) powder, although this temperature limit was raised to about 1100 ° C, due to the chemical incompatibility Of carbon and SiC, however, had the carbon, in particular the carbon fibers, by coating or soaking z. Example by means of phenolic resins or CVD infiltration of methane against direct contact with the SiC be protected, so that a total of a variety of manufacturing steps to manufacture Such a brake disc of so-called. CSiC material was required.

Farther also such CSiC discs had the principal disadvantage - in addition to the high production costs - one high brittleness and very heavy mechanical workability, for example for Balancing purposes.

These so-called ceramic brakes now had a high, about the life of a motor vehicle corresponding life on, as well as very good deceleration values are However, due to the complex manufacturing process very expensive and still have the system inherent disadvantages described.

In addition, it is from the DE 37 38 949 C2 known to arrange on the rotating side (brake disc) an organic friction lining and on the fixed side (brake shoe) a ceramic friction lining.

III. Presentation of the invention

a) Technical task

It is therefore the object according to the invention, to create a wheel brake, despite the soft friction partner on the brake disc and ceramic friction partner on the brake pad a simple fastening and changing the pads, in particular of the disc covering, possible is.

b) Solution of the task

These The object is solved by the features of claims 1 and 2. advantageous embodiments emerge from the dependent claims.

While in previous wheel brakes the softer and faster-wearing material of the friction pairing is used as a brake pad, which is easier to change than the brake disc, according to the invention, the reversal of this principle is proposed:
Due to the specific design of the disc covering according to claim 1 or the inclusion of the block lining according to claim 2 allow a quick and easy installation and replacement of the pads, in particular the disc covering, especially by means of mechanical fasteners.

This reversal is contradictory only at first glance:
- Through the use of ceramic material in the friction pair, the other part of the friction pair, so in this case, the material of the contact surface of the brake disc, be modified so that its life increases, and not as before in a car all about 20,000 40,000 kilometers must be replaced, but only half as often.

The Ceramic material is now in the form of the friction lining of a conventional Brake pad needed.

The Shape and dimensional accuracy, which has to be achieved is in a ceramic part, which yes by sintering as a molded product is produced, and mechanically hardly or only with great effort can be reworked, easier to achieve than the complex one and a high speed during operation, and thus possibly high Imbalanced, brake disc.

The faster-wearing Material of the friction pair is over the relatively large one area the brake disc is distributed while the slower wearing, tougher Material of the friction pairing on the relatively small surface of the Limited brake pad becomes. This approach the life of the two parts of the friction pair, so brake disc and brake pad, against each other, which is the standardization of Replacement intervals of the two parts serves and given the very long service life of the ceramic part of the friction pairing in practice barely represents a disadvantage.

The Production methods and production facilities for previously produced, conventional Brake discs made of metal, such as gray cast iron, can largely continue to be used in which as a base body the brake disc still metal, especially gray cast iron used is, on the frontal surfaces a friction lining is applied using the same technique, with which previously arranged the friction lining on the back plates of brake pads has been.

The Good roundness required for brake discs, so avoidance of Imbalances, can be relatively easily by mechanical post-processing, z. B. facing, the friction lining can be achieved on the brake disc, which is much softer and thus easier to work than that Material of a ceramic brake disc.

All in all This is a wheel brake achieved, the lifetime while a total is slightly lower than that of a ceramic brake in which at least the brake disc on its contact surface of ceramic material exist, however, the manufacturing costs of the brake according to the invention are in contrast drastic lower, among other things, since only 1/6 of the expensive CSiC material is needed and its shape is much simpler.

In addition, the system-inherent disadvantages of the ceramic material for such a wheel brake are less dramatic, since by the - preferably surface - applying the ceramic pad lining on the metal back plate of the brake pad even with breakage of the ceramic coating, the fragments do not dissolve, and thus the brake at least partially remains functional. In addition, the metallic back plate can be structurally designed so that even after destruction and complete release of the ceramic block lining, the metal of the back plate on the back plate / the disc covering comes to fruition and thereby still one although less braking effect can be achieved.

When attaching the coverings on the respective bodies different possibilities are available:
The ceramic pad lining is either completely bonded to the back plate and / or additionally positively secured by receiving in a tapered in the direction of the wheel dovetail guide and / or in the loading direction of the pad lining on the back plate protruding positive stop in the form of a bead etc.

Of the on the brake disc to be applied disc covering must preferably annular shape possess, wherein the ring shape in one piece or composed of individual segments can be achieved. The attachment can be in both cases again either through full-surface Glueing or forceful Attachment, so z. B. riveting, screwing, insertion between projections etc. are achieved. The appropriate mounting surface one from z. B. gray cast iron base body can preferably made sufficiently accurate by turning become.

As already known per se, in these cases, the brake caliper, in the a brake pad fixed and a movably received, preferably floating on the vehicle stored to a surface conditioning of the ceramic To cause block lining on the friction lining of the brake disc.

At the Gluing the coverings on the respective basic bodies On the one hand, the adhesive can at the same time be used as a leveling compound the shape of the parts to be fastened together serve as also called thermal insulation to the respective base body so low as possible to heat up when using the brake.

c) embodiments

A embodiment according to the invention in the following with reference to the figures described in more detail by way of example. Show it:

1 : A disc brake in section,

2a : a first brake pad in the supervision,

2 B : a second brake pad in the supervision,

2c : the brake pad according to 2 B in the direction of the 1

3 : an annular two-piece Scheibenblag in the top view.

4a : a more segmented disc covering in the top view,

4b : the disc of 4a in section,

4c : a similar slice in section, and

4d a radial section through 4a ,

1 is a common disc brake in section along the axial direction 10 shown, wherein in the brake disc shown there 1 on the frontal outer surfaces as a disc covering 21 a respective one-piece annular disc covering 21 or also a segmented disc covering according to 3 Can be used.

1 shows the substantially rotationally symmetrical brake disc 1 with a base body 1a made of metal, in particular gray cast iron, in which from a central hub portion radially outward as an annular disk of the functional part of the base body 1 protrudes. The hub part is frontally with the hub 4 bolted to the vehicle while on the opposite end side of the hub part of the base body 1a the rim of the wheel 3 is seated with its central middle part.

In the annular disk-shaped functional part of the base body 1a are open to the end faces, annular receiving spaces for arranging the annular disc-shaped disc coverings 21 provided thereby characterized on its radially outer side of the existing there widened in the axial direction bead 19 of the base body 1a Partially engaged behind in the axial direction and thereby held in a form-fitting manner radially outward.

In addition, the corresponding axially projecting disc pads 21 , which are preferably formed identically in practice, in the space provided for receiving the base body 1a , the central and radially outward open in the middle of the known ventilation holes 12 distributed over the circumference can aufwei sen, either by surface bonding by means of an adhesive 20 , in particular additionally attached or form-fitting z. B. by screwing by means of screws 24 or - as shown in the lower half - by latching by means of locking pins 17 their locking projections near the front end preferably with the inner surfaces of the ventilation openings 12 caught can or rivets 16 that also has both disc pads 21 can penetrate.

screw 24 , Locking pins 17 and others in the axial direction 10 extending fasteners must be so far compared to the outer contact surface 9 of the disc covering 21 be set back that even with wear of the disc covering 21 still no contact of these elements by the in the axial direction from the outside on the disc surface 21 pressing block coverings 22 the brake pads 2 which is done by a metal back plate 23 are worn and are usually attached thereto by gluing.

The openings 18 in the base body 1 for passing the locking pins 17 or screwing in screws 24 or inserting rivets 16 , in particular of blind rivets 16 , serve, are preferably as extending in the radial direction slots 18 ' educated. Despite the attachment by means of these fasteners may preferably between the mounting surface 8th of the disc covering and the base body 1a a balancing mass 26 be introduced, the manufacturing inaccuracies with respect to the shape of the mutually fixed parts compensated and a two-dimensional force introduction, especially in the disc covering 21 promotes and at the same time as thermal insulation between disc surface 21 and base body 1a can act.

2a shows a brake pad 2 as usual from a back plate 23 and a paddock 22 exists, wherein the block lining 22 however ceramic it contains material or consists of ceramic material.

This is the block lining 22 full surface with the back plate 22 , which has a larger footprint than the block lining 22 , glued and / or additionally by means of a screw 24 screwed. The screw 24 not enough to the outer surface, the contact surface, the disc covering 22 In contrast, it must be sunk sufficiently deep, in order to wear through wear to the wear limit of the block lining 22 permit.

Side of the block lining 22 can the plate 23 also as beside the block lining 22 towering bead 19 ' be formed, as in the right half of the 2a shown to the block lining 22 on the back of the direction of movement 30 support positively relative to the brake disc. Also the height of the bead 19 must be significantly less than the thickness of the block lining 22 ,

2 B shows another brake pad 2 ' in which the block lining 22 in the supervision of 2 B , ie in the axial direction 10 considered - weirdly tapered and inclined side surfaces 13 has, and thus in an analog conical dovetail guide 29 attached to the back plate 23 is formed, can be inserted, preferably against the relative direction of movement 30 of the brake pad 2 opposite the brake disc 1 ,

This will cause the lining pad to brake when braking 22 in the dovetail lead 29 pressed in the direction of the cone and kept free of play. Nevertheless, preferably on the open side of the dovetail guide 29 with the greater distance of the guides a fuse strip 27 '' be provided on the back plate 23 can be screwed and pulling out of the block lining 22 from the dovetail guide 29 prevented. Instead, and / or additionally, a block lining 22 flat with the back plate 23 be glued.

3 points in the axial direction 10 looks at the disc covering 21 on the brake disc 1 , wherein the disc covering 21 divided into two half rings, and thereby the radial attachment and screwing of the two segments 21a 21b to the brake disc 1 is possible, even without dismounting them from the hub.

In contrast, shows 4 in the same direction as 3 a highly segmented disc covering 21 which consists of more than 2 segments:
4 shows in the supervision of the 4a a brake disc 1 in which on the base body 1a in the desired ring area no one-piece annular disc covering 21 is applied, but this is composed of distributed over the circumference of individual segments 6a . 6b . 6x ,

The individual segments 6 are in the circumferential direction spaced from each other and thus form expansion joints between them, which can be larger and smaller in thermal expansion of the individual segments. The outer periphery of the disc covering 21 and thus also the segments 6 enclosing bead 19 of the base body 1a , which provides additional protection against radial rockfall, can be seen as well as - in the upper part of the picture 4a - A precisely radial course of the expansion joints between the individual segments, resulting in a segment shape, the width of which is greater on the outer circumference than on the inner circumference.

This is true even for those in the right half of the 4a represented segments 6a . 6b However, there is the expansion joint between the segments under an always the same intermediate angle 7 inclined to the radial direction to the rotation of the brake disc and adjacent brake pad the Expansion joint can not be reached over its entire radial width at once in the area of the brake pad.

4b shows an anti-rotation between the segments and the base body 1a - Regardless of the attachment between them by means of gluing and / or riveting, screwing, locking - in which the base body 1a in the region of the expansion joints axially outwardly projecting webs 15 ' that exists between the - in 4b parallel to each other axially outwardly aspiring - side surfaces 13 two adjacent segments 6a . 6b , intervene as in the left half of the picture 4b shown. The right half shows the reverse shape, so the formation of radial elevations 25 on the segment 6 which engages in a corresponding depression in the base body, thereby unnecessarily weakens it.

In the lower half of the 4a In contrast, another form of attachment is shown, which in the sectional view of 4c you can see:
The individual segments have this 6x at the supervision of 4a considers a shape tapering from the inner circumference to the outer circumference so that the expansion joints between the segments 6x Broadening from the inside to the outside, and thus also the webs located there 15 that from the base body 1a protrude axially outward.

However, this allows these webs 15 dovetail-shaped and, accordingly, the radially extending side surfaces of the individual segments 6x analog inclined, so from the mounting surface 8th to the outer contact surface 9 towards the radial longitudinal center of the segment 6x rising, training.

The inclination of the side surfaces 13 and thus the bridges 15 and the rejuvenation of the entire segment 6x radially outward are chosen so that the individual segments 6x from the center of the brake disc radially outward between the dovetailed webs 15 can be inserted and fixed by pressure radially outward self-centering. In this position can be a screw etc. or even surface bonding to the mounting surface 8th done or even a positive lock by applying a retaining ring 27 on the radially inner circumference of the individual segments 6x after they are all in position.

By slight radial displacement of this circlip 27 can be made in a simple manner, a balancing of the mounted brake disc.

There is the disadvantage that the webs 15 between the individual segments 6x Be very wide radially outward and an increasing proportion of the circumference is not occupied by friction lining.

As in the upper half of the 4a represented, the segments can 6y Conversely, so also widening radially outward conical, with over the radial extent of equal width, in particular exactly jet-shaped extending webs 15 , Accordingly, then the insertion of the segments 6y radially from outside to inside. The segments 6y must then by a radially applied to the outer circumference circlip 27 ' , which at the same time functions as the bead 19 be secured against the action of centrifugal force, the retaining ring 27 ' annular in one piece or also segmented, for example, from two to four parts exists.

1

brake disc

2

brake pad

3

wheel

4

hub

5

caliper

6a, b, x

segment

7

intermediate angle

8th

mounting surface

9

contact surfaces

10

axially

11

main level

12

ventilation opening

13

faces

14

undercut

15

web

16

rivet

17

Plunger

18

opening

19

bead

20

Glue

21

disk liner

22

Klotz covering

23

backplate

24

screw

25

radial survey

26

Leveling compound

27

circlip

28

openings

Claims (10)

Wheel brake, comprising - one with the wheel ( 3 ) with rotating brake body, in particular a brake disc ( 1 ), with a disc covering ( 21 ), - at least one not with the wheel ( 3 ) co-rotating, pressed against the brake body, brake pad ( 2 ) with one on its back plate ( 23 ) held pad ( 22 ), in which - the block lining ( 22 ) comprises ceramic material, characterized in that - the disc covering ( 21 ) from opposite the brake pad lining ( 22 ) softer materials, and - the disc covering ( 21 ) on each page from several segments ( 6a . 6b ) consists. Wheel brake according to claim 1, comprising - one with the wheel ( 3 ) with rotating brake body, in particular a brake disc ( 1 ), with a disc covering ( 21 ), - at least one not with the wheel ( 3 ) co-rotating, pressed against the brake body, brake pad ( 2 ) with one on its back plate ( 23 ) held pad ( 22 ), wherein - the block lining ( 22 ) comprises ceramic material, and - the disc covering ( 21 ) made of organic material such as the pad pads ( 22 ) consists of conventional gray cast iron brake discs, characterized in that - the block lining ( 22 ) by receiving in a running direction of the wheel ( 3 ) conically tapered dovetail guide of the back plate ( 23 ) is positively secured. Wheel brake according to one of the preceding claims, characterized in that the back plate ( 23 ) of the brake pad ( 2 ) consists in particular of metal. Wheel brake according to one of the preceding claims, characterized in that the softer material of the disc covering ( 21 ) an organic material such as the pad pads ( 22 ) is for conventional gray cast iron brake discs. Wheel brake according to one of the preceding claims, characterized in that the base body ( 1a ) of the brake disc in particular of a metal, in particular a steel material, in particular of gray cast iron, consists. Wheel brake according to one of the preceding claims, characterized in that the disc covering ( 21 ) with the base body ( 1a ) is glued over the entire surface. Wheel brake according to one of the preceding claims, characterized in that the disc covering ( 21 ) with the base body ( 1a ) is positively connected, in particular screwed, riveted or latched and in particular with the same securing element both with respect to the main plane of the base body ( 1a ) opposite disc pads ( 21a . 21b ) simultaneously on the base body ( 1a ) are attached. Wheel brake according to one of the preceding claims, characterized in that the movable brake pad ( 2 ) in the brake caliper ( 5 ) is floating. Wheel brake according to one of the preceding claims, characterized in that the brake caliper ( 5 ) is floating on the vehicle. Method for producing a wheel brake with - a brake disk ( 1 ), which has a base body ( 1a ) made of metal and a disc covering ( 21 ) and - a brake pad ( 2 ), characterized in that the disc covering ( 21 ) is changed by disassembling the metal base body ( 1a ) of the brake disc ( 1 ) the segmented disc pads on both sides on the base body ( 1 ) and secured to the base body after respective rotation of the base body ( 1a ) into the brake caliper ( 5 ) opposite position.