DE102020100517A1 - Internally ventilated brake disc - Google Patents

Abstract

An internally ventilated brake disc, in particular for a commercial vehicle, with two spaced friction rings (1) which are connected to one another by webs (2) which are arranged on several concentric circles (4) to (7) and are arranged on several concentric circles (4) to (7) are connected to one another, is characterized in that at least a part (d) of the webs (2) of each circle are arranged at different distances (a, b, c) from one another and the webs (2) of each circle (4 to 7) are offset from the webs (2) of the adjacent circle ( 4 to 7) are arranged on a line (X) which deviates from a radial orientation.

Description

The invention relates to an internally ventilated brake disc according to the preamble of claim 1.

Such brake disks are used in particular in brake systems of commercial vehicles, and when they are functioning, i.e. during braking, they correspond to brake linings whose friction sides are pressed against the brake disk on both sides.

In order to reduce the thermal load on the brake disc due to the frictional heat generated during braking, the brake disc has cooling channels in the space formed between two friction rings, through which heat is given off in the form of convection and thermal radiation.

To connect the two friction rings, which are positioned parallel and spaced from one another, webs are provided, between which the cooling channels are formed.

According to the generic type, these webs, which are preferably designed in the shape of bolts, with a round or non-round cross section, are arranged on several concentric circles. Such a brake disc is for example in the DE 102 41 655 A1 disclosed, wherein the distances between the webs of the respective circles are equal to one another.

However, it has been shown that with such a construction t so-called hotspots are formed, i.e. hot points on the friction rings that are evenly distributed over the circumference, which is known as "hot scratching".

The consequence of these hotspots is that more heat cracks form, which significantly reduce the service life of the brake disc, with the heat cracks growing radially outwards, starting from approximately the center of the respective friction ring.

In addition, a change in the surface of the outer sides of the friction rings can be observed due to the action of heat.

Attempts have already been made to achieve a homogeneous pressure distribution by selecting a suitable friction material for the brake linings, but these previously described harmonic hotspots always occur, which lead to local overheating of the friction surfaces.

This results in metallurgical transformations and, as a result, embrittlement of the surface of the friction rings, which in turn contributes to the aforementioned crack formation. This crack formation considerably reduces the service life of the brake disc, which leads to corresponding costs, which arise on the one hand from the replacement of brake discs and on the other hand from the necessary assembly times and downtimes of the vehicle.

Further attempts to minimize or completely exclude the occurrence of hotspots, in particular by changing the configuration of the webs or cooling channels or by using vane ribs that connect the friction rings to one another, were not effective. Exemplary in this regard are the WO 2012/164 465 A1 , the WO 2015/092 671 A1 or the DE 40 40 423 A1 called.

The invention is therefore based on the object of further developing a brake disk of the generic type in such a way that its service life is improved and the operating costs are reduced overall.

This object is achieved by a brake disk with the features of claim 1.

The invention creates an arrangement pattern of the webs such that at least some of the webs of each circle are arranged at different distances from one another. In addition, the webs of each circle are offset clockwise or counterclockwise to the webs of the adjacent circle on a line that deviates from a radial orientation.

The cross-sectional dimensions of the webs can be the same or different, the latter preferably, the dimensions of the webs increasing as the radius of the circles increases. However, a design is also conceivable in which the dimensions of the webs arranged on the inner circle are larger than those arranged on an adjacent circle.

According to a further concept of the invention, the arrangement of the webs of a circle is repeated several times on the circle, so to speak, as a group at different distances. However, a stochastic arrangement of the web spacings of a circle is also conceivable.

The number of bars arranged on a circle can be the same or different on all circles.

As has surprisingly been shown, the change in the arrangement of the webs means that the rigidity of the curl varies continuously in the circumferential direction. This variation disrupts the harmonious formation of corrugations, whereby the number of so-called hotspots is reduced, with the result that one Surface damage from overheating is minimized.

Avoiding curling of the friction ring surfaces not only improves braking comfort, since the rubbing described in the prior art no longer occurs during braking, but the significant reduction in the formation of heat cracks also significantly increases the service life of the brake disc.

Since a large number of brakes and thus brake disks are mounted in a utility vehicle, this result of the invention is of particular importance, in particular with regard to a cost minimization that is always sought. This results both from the reduced downtime of the vehicle and from the procurement and assembly of the brake discs.

Incidentally, the new brake disk can be manufactured at no cost compared to one according to the prior art, such brake disks usually being made of cast iron.

According to the invention, the webs are arranged in several concentric circles, preferably in four circles. However, a smaller or larger number of circles is also conceivable, the webs of a circle according to the invention being arranged at different distances from one another.

As described in relation to the prior art, heat cracks always form in the radial direction. The arrangement of the webs according to the invention therefore has the effect that each point of the friction surfaces in the radial direction has a connection with the opposite friction ring at at least one point of the so-to-speak radial “heat jet” in the cooling channel formed.

As has also been shown, the inventive arrangement of the webs achieves an improved cooling performance, as a result of which the maximum temperature of the friction ring surfaces is reduced, which contributes to minimizing the rate of crack growth.

The offset arrangement of the webs on a line deviating from a radial alignment means that a heat crack always hits the surface of a web projected onto the friction surface during its radial propagation, which hinders or stops the heat crack growth.

Further advantageous designs are characterized in the subclaims.

An exemplary embodiment of the invention is described below with reference to the accompanying drawing.

The single figure shows a section through a brake disk according to the invention in a plan view.

The figure shows a brake disc, in particular for a utility vehicle, which has two friction rings arranged parallel and spaced from one another 1 having, with only one friction ring in the figure through the sectional view 1 can be seen.

The two friction rings 1 are by footbridges 2 connected to one another and in the example have a circular cross-section which, deviating from this, can also be non-circular.

The bridges 2 are on concentric circles indicated in the figure 4th to 7th arranged, four of these circles are provided in this arrangement.

According to the invention are at least a part d of each circle 4-7 associated bars 2 at different distances a , b , c arranged to one another, that is, the webs 2 are on each of the circles 4-7 unevenly distributed.

In the example, the part is repeated d evenly over the respective circle 4th to 7th in its scope. However, it is also conceivable that the distances between all webs of a circle 4-7 to form different from each other over the entire circumference.

Furthermore, 30 webs are arranged on each circle in the example. Alternatively, 20 to 40 can also be provided. Since the webs are not arranged radially aligned along a line X, but offset from one another from the inside to the outside, starting from a radial line R there is at least one web 2 cut. The non-radial line X forms an angle α with the radial line R which is 20 ° to 45 °, for example 27 °.

The webs of adjacent cross-sectional centers 2 The connecting line X is similar to the contour of ventilation ribs, which means that no heat crack can spread in the radial direction without a ridge 2 hold true. The webs positioned on two lines X arranged at a distance from one another limit this 2 a cooling channel 3 .

Incidentally, the cross-sections of the webs are 2 which, according to the invention, can be offset both clockwise and counterclockwise, at least so large that along the radial line R at least one web 2 is intersected by this radial line R.

Deviating from the representation in which the line X is present as a straight line, the offset arrangement can be aligned on a line X describing an arc. The radius of the curved line X can be constant or variable, for example as a clothoid or in an S-shape.

List of reference symbols

1

Friction ring

2

web

3

Cooling duct

4th

circle

5

circle

6th

circle

7th

circle

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 10241655 A1 [0005]
• WO 2012/164465 A1 [0011]
• WO 2015/092671 A1 [0011]
• DE 4040423 A1 [0011]

Claims (10)

Internally ventilated brake disc, in particular for a commercial vehicle, with two spaced friction rings (1) which are connected to one another by webs (2) which are arranged on several concentric circles (4) to (7) and are arranged on several concentric circles (4) to (7), characterized in that at least one Part (d) of the webs (2) of each circle are arranged at different distances (a, b, c) from one another and the webs (2) of each circle (4 to 7) are offset from the webs (2) of the adjacent circle (4 to 7) 7) are arranged on a line (X) that deviates from a radial orientation. Internally ventilated brake disc after Claim 1 , characterized in that several of the parts (d) are periodically arranged on at least one of the circles (4 to 7). Internally ventilated brake disc after Claim 1 or 2 , characterized in that one part (d) of webs (2) is arranged on the entire circumference of the respective circle (4 to 7). Internally ventilated brake disc according to one of the preceding claims, characterized in that the number of webs (2) of each circle (4 to 7) is the same. Internally ventilated brake disc according to one of the preceding claims, characterized in that the cross-sections and / or the contour of the webs (2) are the same or different. Internally ventilated brake disc according to one of the preceding claims, characterized in that the webs (2) are round or non-round in cross section. Internally ventilated brake disc according to one of the preceding claims, characterized in that the webs (2) arranged on the line (X) deviating from the radial alignment are arranged clockwise or counterclockwise. Internally ventilated brake disc according to one of the preceding claims, characterized in that the line (X) deviating from the radial alignment is a straight line, an arc or S-shaped. Internally ventilated brake disc according to one of the preceding claims, characterized in that the line (X) deviating from the radial alignment runs at an angle of 20 to 45 ° to the radial line (R). Internally ventilated brake disc according to one of the preceding claims, characterized in that the cross section of at least one of the webs (2) arranged on the line (X) deviating from the radial alignment is so large that it is intersected by the radial line (R).

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