GB2481112A

GB2481112A - Internally ventilated disc brake having two friction rings of a first material and an inner part of a second material

Info

Publication number: GB2481112A
Application number: GB1109391.1A
Authority: GB
Inventors: Francesco Germano; Oliver Moessinger
Original assignee: Dr Ing HCF Porsche AG
Current assignee: Dr Ing HCF Porsche AG
Priority date: 2010-06-11
Filing date: 2011-06-03
Publication date: 2011-12-14
Anticipated expiration: 2031-06-03
Also published as: GB201109391D0; CN202251573U; DE102010023501A1; ITMI20110944A1; GB2481112B; FR2961282B1; FR2961282A1

Abstract

An internally ventilated brake disk 1, having two friction rings 2, 3, which comprise a first material, preferably a ceramic; and an inner part 6, which is arranged substantially axially between the friction rings 2, 3 and when attached to the friction rings 2, 3, forms air ducts 15, wherein the inner part 6 comprises a second material, preferably steel; the second material differing from the first material. The inner part 6 may be extruded or cast. The inner part may connect to a nave 7 (for attachment of the brake disc to a wheel hub) by connecting elements 12, such as pins, locked in a spring clip (25, fig 3).

Description

Internally ventilated brake disk The present invention relates to an internally ventilated brake disk.

An internally ventilated brake disk is known from the publication DE 195 37 392 Al, for example. This known brake disk has two opposite friction rings, arid connecting ribs that ic connect the friction rings to one another are arranged between the latter. Together with the friction rings, the connecting ribs form air ducts.

For motor sport applications, in particular, the known ----i5-interna-1ly--ven.tilated.brakediskis.prOduc.e from a solid ceramic. This is already very expensive owing to the high costs for the ceramic material. Moreover, the production of the connecting ribs from ceramic is also a very involved process in terms of manufacturing technology.

The invention seeks at least to reduce the disadvantages described above, in particular.

According to the invention, this may be achieved by an internally ventilated brake disk having the features of patent claim 1.

The concept underlying the present invention consists in arranging a separate inner part between the two friction rings, with said inner part forming air ducts together with the friction rings and being formed from a different material than the friction rings. This opens up the possibility of making the inner part from an inexpensive material which is also easy to work. The friction rings, on the other hand, continue to be formed from a high-grade material that has the thermal properties required for braking and the required s strength. In addition, the inner part can thus be produced separately from the two friction rings. Furthermore, the same inner part can be used together with friction rings of different diameters and/or of different thickness since it is formed separately from the two friction rings, i.e. not integrally therewith. It iS thus possible to achieve cost advantages and advantages in terms of manufacture and assembly.

Advantageous embodiments and improvements of the brake disk is specified in patent claim 1 can be fOUnd in th sub m ---, In the present case, the terms "axially"1 "radially" and "in the circumferential direction" always refers to the center line of the brake disk, unless stated otherwise.

According to a preferred development of the brake disk according to aspects of the invention, the first material is a ceramic and/or the second material is a metal, especially steel. Suitable steels include low-pressure diecasting steel, ifl particular. An inner part made of metal can be produced easily, especially in comparison with an inner part made of ceramic. The friction rings made of ceramic fulfill the abovementiorted thermal requirements and are also advantageous in terms of their strength. As an alternative, the second material can also be a ceramic waste product.

According to a more preferred development of the brake disk according tO the invention, the inner part is designed as an extruded or cast part. This enables the geometry of the inner part to be produced easily.

S

According to a more preferred development of the brake disk according to aspects of the invention, the inner part has a plurality of substantially radially extending web elements, which form the air ducts therebetWeen, the web elements connecting the friction rings to one another. Air ducts are thereby formed in a simple manner between the friction rings.

Here, "substantiallY radially" also includes those web elements which curve in the circumferential direction, that is to say, for example, are crescent-shaped.

According to a more preferred development of the brake disk according to aspects of the invention, the inner part has at least one support element, which extends su]Dstarltially in the circumferential direction and is firmly connected to the web elements, the support element being designed to be narrower in the axial direction than the web elements. Thus, the air ducts formed between the web elements and the friction rings are only slightly obstructed by the support element, i.e. au air flow through the air ducts is impaired to only an insignificant extent.

According to a more preferred development of the brake disk according to aspects of the invention, the inner part is connected radially on the inside, by means of substantially radially movable connecting elements, to a nave for attachment of the brake disk to a wheel hub. Thermally induced stress between the nave and the friction rings together with the inner part can thereby be avoided.

According to a more preferred development of the brake disk according to aspects of the invention, at least one of the connecting elements is locked in the axial direction by a spring clip. This allows easy and rapid mounting of the nave on the inner part.

io According to a more preferred development of the brake disk according to aspects of the invention, the at least one spring clip is arranged in a recess in the nave or in the inner part.

More preferably, the spring clip has an opening in the axial and the radial direction. Even more preferably, the spring is clips surround at least a section of the connecting eleteits..

in the locked state. This development makes it possible simply to press the nave into the friction rings together with the inner part, thereby creating a connection with only radial mobility between the nave and the inner part by locking the recesses with the connecting elements.

According to a more preferred development of the brake disk according to aspects of the invention, the connecting elements are designed as pins. By means of the latter, the abovemeritioned radial mobility can be implemented in a manner which is simple in terms of design.

According to a more preferred development of the brake disk according to aspects of the invention, the inner part is of 3o integral design. An inner part of this kind is easy to produce and mount.

S

The invention is explained in greater detail below by means of illustrative embodiments with reference to the attached figures of the drawings.

s In the figures: Fig. 1 shows a brake disk in accordance with one illustrative embodiment of the present invention in a perspective view; Fig. 2 shows the view from Fig. ]. but with one of the friction rings removed; and Fig. 3 shows an enlarged view of Fig. 2, with one of the recesses being shown with the connecting element and the other recess being shown without the connecting element.

i In the f±gures of *the-drawings,. -the same. reference signs denote identical or functionally identical components, unless stated otherwise.

Fig. 1 illustrates an internally ventilated brake disk 1 in accordance with one illustrative embodiment of the present invention in a perspective view.

The brake disk 1 has two friction rings 2, 3, which are arranged coaxially with respect to a center line M of the brake disk 1.

In the present case, the terms "axially", "radially" and "in the circumferential direction" always refer to the center line M of the brake disk 1, unless stated otherwise.

The friction rings 2, 3 are formed from a first material, which is a ceramic according to the illustrative embodiment under consideration. On the outside, the friction rings 2, 3 have friction surfaces 4, 5, which are set up to interact with brake pads (not shown) in order to brake a motor vehicle.

s Arranged on the inside, between the friction rings 2, 3, is an inner part 6, which is separate from the latter. The inner part 6 is formed from a second material, which differs from the first material. According to the illustrative embodiment under consideration, the inner part 6 is designed as a cast part made of steel.

The brake disk 1 furthermore has a nave/hub 7 for attaching the brake disk 1 to a wheel hub (not shown) of the motor vehicle. For this purpose, the nave 7 has a plurality of i -openings --8-for corresponding. bolt (not shown). The nave 7 is connected to the inner part 6 by means of connecting elements 12 in a manner which allows radial mobility in order to avoid thermally induced stresses.

Fig. 2 shows the view from Fig. 1 but the friction ring 2 is not shown, thus exposing the inner part 6 to view.

The inner part 6 has a plurality of web elements 13 which, together with inner surfaces 14 of the friction rings 2 arid 3, define radial air ducts 15. Owing to the depiction in Fig. 2, the inner surface of the friction ring 2, which is not shown, is not visible. The web elements 13 extend radially and simultaneously curve in the circumferential direction.

According to the illustrative embodiment under consideration, the web elements 13 are of approximately crescent-shaped design. Thus, according to the illustrative embodiment under consideration, the air ducts 15 taper radially inward in terms of the cross section thereof.

The inner part 6 furthermore has two support elements 16, s which are firmly connected to the web elements 13, giving a grid-like structure to the inner part 6. As is also apparent from Fig. 1, the web elements 13 extend over the entire gap 17, see Fig. i, between the inner surfaces 14 of the friction rings 2 and 3, connecting the friction rings 2 and 3 to one io another. For this purpose, projections 18 can be formed integrally on the web elements 13, said projections engaging in holes 19, see Fig. 1, in the friction rings 2, 3. By way of example, a press fit can be provided between each projection 18 and hole 19. The web elements 13 thus connect the two friction rings 2 and? the cjrcumferenti drecQa irL --the radial direction, in particular positively. By means of the abovementiorled press fit, it is also possible to create a frictional connection between the friction rings 2 and 3 in the axial direction. It would also be possible to provide rivets instead of the projectionS 18.

As is apparent from Fig. 2 the support elements 16 have a thickness D which is less than that of the web elements 13, and therefore the support elements 16 extend across only part of the gap 17, thus ensuring that the air ducts 15 formed are only slightly impaired by the support elements 16.

As Fig. 2 furthermore illustrates, a plurality of recesses 22 are formed on the nave 7, e.g. in axial projections 23 on the latter. The recesses 22 are of open design both in the axial and in the radial direction. The connecting elements 12 of the inner part 6, which are designed as pins, engage in the recesseS 22 in a manner which allows radial mobility. The connecting elements 12 can be formed integrally on the radially inner ends 24 of the web elementS 13, f or example.

Fig. 3 shows two projectionS 23 on the nave 7 in an enlarged view of Fig. 2. Apart from the connecting elements 12, the inner part 6 is not shown in Fig. 3 for the sake of greater clarity.

A spring clip 25 made from spring steel, for example, is inserted into each of the recesses 22. Each of the spring clips 25 essentially has a U shape, with the free ends 26 thereof bent back in the axial direction. Each of the spring clips 25 thus forms an axial opening 27 and a radial opening 28. The spring clips 25 each surround Co eçipg_e.1eiTer1t 12 at the circumference thereof.

The manufacture and assembly of the brake disk 1 will be explained briefly below.

First of all, the friction rings 2 and 3 are produced from ceramic, this being a simple matter since the friction rings 2 and 3 have a constant cross section in the circumferential direction.

In advance, in parallel or afterwards, the inner part 6 is cast from steel.

After this, the inner part 6 is arranged between the friction rings 2 and 3 and is pressed together with the latter axially, with the projectionS 18 on the inner part 6 coming into engagement with the holes 19 in the friction rings 2 and 3.

Keeping the hole pattern of the holes 19 the same, it is possible to vary the thickness of the friction rings 2, 3 or even the inside or outside diameter thereof while nevertheless using the same inner part 6 together with these friction rings s 2, 3.

The nave 7 is then pressed into the friction rings 2, 3 in the axial direction, together with the inner part 6. During this process, the connecting elementS 12 are moved into the axial openings 27 in the spring clips 25, the free ends 26 of the spring clips 25 are thereby spread apart elastically, and then the connecting elements 12 are locked behind the free ends 26 of the spring clips 25. At the same time, however, the connecting elementS 12 can move in the spring clips 25 by is means of the radial openings 28 in order to avoid the -------thermally induced stress discussed.

Although the present invention has been described above by means of preferred illustrative embodiments, it is not limited thereto but can be modified in many different ways.

Claims

Patent claims 1. An internally ventilated brake disk, having: two friction rings, which comprise a first material; and an inner part, which is arranged substantiallY axially between the friction rings and, together with the latter, forms air ducts, wherein the inner part comprises a second material; the second material differing from the first material.
2. The brake disk as claimed in claim 1, wherein the first material is a ceramic and/or the second material is a metal, especially steel.--------
3. The brake disk as claimed in claim 1 or 2, wherein the inner part is designed as an extruded or cast part.
4. The brake disk as claimed in at least one of the preceding claims, wherein the inner part has a plurality of substantially radially extending web elementS which form the air ducts therebetweefl, the web elements connecting the friction rings to one another.
5. The brake disk as claimed ifl claim 4, wherein the inner part has at least one support element, which extends substantia1lY in the circumferential direction arid is firmly connected to the web elements, the support element being designed to be narrower in the axial direction than the web elements. 1.1
6. The brake disk as claimed in at least one of the preceding claims, wherein the inner part is connected radially on the inside, by means of substantially radially movable connecting elements, to a nave for s attachment of the brake disk to a wheel hub.
7. The brake disk as claimed in claim 6, wherein at least one of the connecting elements is locked in the axial direction by a spring clip.
8. The brake disk as claimed in claim 7, wherein the at least one spring clip is arranged in a recess in the nave or in the inner part.is9. The brake disk as claimed mat least one of claims 6 to 8, wherein the connecting elements are designed as pins.10. The brake disk as claimed in at least one of the preceding claims, wherein the inner part is of integral design- 11. A brake disk, substantially as hereinbefOre described with reference to any of the accompanying drawings.