Bremsscheibe (Brake Disc)

Abstract

A brake disk (1) has a brake disk chamber (2), a friction ring (3) having two friction ring disks (3a, 3b) and a plurality of pin-shaped connecting elements (4) for connecting the brake disk chamber (2) and the friction ring (3). A cooling duct (5) is formed between the fiction ring disks (3a, 3b). The friction ring disks (3a, 3b) have respective friction surfaces (3a1, 3b1) on their outer planar surfaces and respective cooling channel surfaces (3a2, 3b2) on their inner planar surfaces. The friction ring (3) has a plurality of receiving regions (7) for receiving the pin-shaped connecting elements (4). The brake disk chamber (2) is cast to the connecting elements (4) in a separate step by means of casting. A gap (8) existing between the brake disk chamber (2) and the friction ring (3) has such a width (A) which results from the fact that, during casting of the brake disk chamber (2), at least one section (3d) of a lateral surface (3c) of the inner diameter of the friction ring (3) which is closed in itself in the circumferential direction is used as part of a casting mold (9). An axial extension of that part of the receiving area (7) of the friction ring (3) which extends from the cooling channel surface (3a2) in the direction of the cooling channel (5) is 2-10 mm, preferably 4-7.5 mm, even more preferably 5.5 mm.

Claims

1. Brake disk having a brake disk chamber, a friction ring having two friction ring disks and a plurality of pin-shaped connecting elements for connecting the brake disk chamber and the friction ring, a cooling duct being formed between the fiction ring disks, the friction ring disks having respective friction surfaces on their outer planar surfaces and respective cooling channel surfaces on their inner planar surfaces, the friction ring having a plurality of receiving regions for receiving the pin-shaped connecting elements, and the brake disk chamber being cast to the connecting elements in a separate step by means of casting, characterized in that a gap existing between the brake disk chamber and the friction ring has such a width which results from the fact that, during casting of the brake disk chamber, at least one section of a lateral surface of the inner diameter of the friction ring which is closed in itself in the circumferential direction is used as part of a casting mold, and that an axial extension of that part of the receiving area of the friction ring which extends from the cooling channel surface in the direction of the cooling channel is 2-10 mm, preferably 4-7.5 mm, even more preferably 5.5 mm.

2. Brake disk according to claim 1, characterized in that the gap has a width of 0.1-1.5 mm, preferably 0.57-1.0 mm, even more preferably 0.7 mm.

3. Brake disk according to claim 1, characterized in that 21-42, preferably 27-32, connecting elements are provided to connect the brake disk chamber and the friction ring.

4. Brake disk according to claim 1, characterized in that the connecting elements have a diameter of 3-6.5 mm, preferably 4-5.5 mm, even more preferably 5 mm.

5. Brake disk according to claim 1, characterized in that the connecting elements each have a length of 20-30 mm, preferably 22-26 mm.

6. Brake disk according to claim 1, characterized in that the connecting elements are conical and have a cone angle of 0.6°-3.6°, preferably 1.6°-2.6°.

7. Brake disk having a brake disk chamber, a friction ring and a plurality of connecting elements for connecting the brake disk chamber and the friction ring, characterized in that 21-42, preferably 27-32, connecting elements are provided to connect the brake disk chamber and the friction ring.

8. Brake disk having a brake disk chamber, a friction ring and a plurality of connecting elements for connecting the brake disk chamber and the friction ring, characterized in that the connecting elements have a diameter of 3-6.5 mm, preferably 4-5.5 mm, even more preferably 5 mm.

9. (canceled)

10. (canceled)

Description

[0038] In the following, examples of the invention are shown in principle on the basis of the drawing.

[0039] In the drawings:

[0040] FIG. 1 is a sectional view of a first embodiment of a brake disk according to the invention;

[0041] FIG. 2 is an enlarged representation according to line II of FIG. 1;

[0042] FIG. 3 is a sectional view of a brake disk known from the state of the art;

[0043] FIG. 4 shows the brake disk according to the invention in a view corresponding to FIG. 3;

[0044] FIG. 5 is a sectional view of a tool for manufacturing the brake disk according to the invention;

[0045] FIG. 6 is another view of the tool for manufacturing the brake disk according to the invention;

[0046] FIG. 7 is a partially cut front view of the brake disk according to FIGS. 1, 2 and 4;

[0047] FIG. 8 is a sectional view of a second embodiment of a brake disk according to the invention;

[0048] FIG. 9 is an enlarged view according to line IX of FIG. 8;

[0049] FIG. 10 is a partially cut perspective view of the brake disk according to the invention;

[0050] FIG. 11 is a partially cut front view of the brake disk according to FIG. 10; and

[0051] FIG. 12 shows a section of the developed view of the inner diameter of the friction ring of a brake disk according to the invention, showing the axial extension “X” of the area of the friction ring for the connecting elements.

[0052] FIG. 1 shows an internally ventilated brake disk 1 designed as a composite brake disk and having been optimized for cooling as described below, which has, in a manner known to the expert, a brake disk chamber 2, around the circumference of which a breaking band or friction ring 3 is placed. The friction ring 3 has two friction ring disks 3a and 3b and is connected to the brake disk chamber 2 by means of several pin-shaped connecting elements 4 extending in a radial direction from the brake disk chamber 2 to the friction ring 3. The friction ring 3 is mounted in a gliding or sliding way on the pin-shaped connecting elements 4, which means that it can expand freely and unhindered in the radial direction during thermal loading of the brake disk 1 and is therefore less susceptible to crack formation.

[0053] On their outer end faces, the friction ring disks 3a and 3b have respective friction surfaces 3a1 and 3b1, which are only shown in FIG. 2 for the sake of clarity. A cooling channel 5 is formed between the friction ring disks 3a and 3b through which cooling air can flow outwards through the friction ring 3 from the direction of the brake disk chamber 2 during operation of the brake disk 1 in a known manner. On their inner end faces, the friction ring disks 3a and 3b have respective cooling channel surfaces 3a2 and 3b2, which are also only marked in FIG. 2. The cooling channel surfaces 3a2 and 3b2 are thus opposite the friction surfaces 3a1 and 3b1. Within the cooling channel 5, there are several connecting webs 6, which connect the friction ring disks 3a and 3b to each other in a known manner. Furthermore, the friction ring 3 has several receiving areas 7 for receiving the pin-shaped connecting elements 4. These will be described in more detail later.

[0054] In a known manner, the brake disk chamber 2 forms the connection of the brake disk 1 to a not shown chassis of a vehicle equipped with brake disk 1. In addition, brake pads not shown in the figures are applied to the friction ring 3 in a similarly known manner to achieve the desired deceleration of the vehicle. The connecting elements 4 transmit the braking torque acting on the friction ring 3 to the brake disk chamber 2 and thus to the vehicle. The connecting elements 4 are thus exposed to very high loads and it is essential for the effect of the brake disk that the connecting elements 4 remain intact.

[0055] One of the connecting elements 4 is shown in FIG. 1 in a sectional view. It can be seen that the connecting element 4 used to connect the brake disk chamber 2 with the friction ring 3 in the embodiment of FIGS. 1-7 of the brake disk 1 is essentially cylindrical. This makes it possible to use standard parts or components that are only slightly modified from standard parts, such as dowel pins, as the connecting elements 4. In the embodiment of the brake disk 1 shown in FIGS. 1-7, the connecting elements 4 have a diameter of 3-6.5 mm, preferably 4-5.5 mm, even more preferably 5 mm. The length of the connecting elements 4 for the embodiment of the brake disk 1 shown in FIGS. 1-7 is 20-30 mm, preferably 22-26 mm. The diameter and the length of the connecting elements 4 can be in a certain ratio to each other, in principle, however, both the diameter and the length can be freely selected in the areas mentioned.

[0056] There is a gap 8 between the brake disk chamber 2 and the friction ring 3, which is comparatively large for conventional brake disks, such as the brake disk described in DE 10 2016 122 321 A1. FIG. 2 of DE 10 2016 122 321 A1 shows the size of this gap between the brake disk chamber and the friction ring. Such a large gap, which is common for all known composite brake disks, allows much of the cooling air necessary for cooling the friction ring 3, through which air can flow as described above, to flow out or to disperse, which can lead to excessive heating of friction ring 3.

[0057] In contrast, the gap 8 between the brake disk chamber 2 and the friction ring 3 of the brake disk 1 according to the invention has a width of 0.1-1.5 mm, preferably 0.5-1.0 mm, and even more preferably 0.7 mm, i.e. a much smaller width than usual. As a result, less air can flow out through the gap 8 and more air enters the cooling chamber 5 between the friction ring disks 3a and 3b of friction ring 3, thus leading to a better cooling of the friction ring 3.

[0058] A comparison of FIGS. 3 and 4 clearly shows the difference between the brake disk shown in FIG. 3 according to DE 10 2016 122 321 A1 and the brake disk 1 according to the invention. While the brake disk shown in FIG. 3 allows a great amount of cooling air to flow out through the very large gap 8 of the brake disk according to the state of the art, this is prevented by the very small gap 8 of the brake disk 1 according to the invention. The cooling air flow is shown in FIGS. 3 and 4 by means of arrows. The larger number of arrows in FIG. 4 shows that much more cooling air can flow through the cooling channel 5 between the friction ring disks 3a and 3b of the friction ring 3 of the brake disk 1 according to DE 10 2016 122 321 A1 than through the cooling channel 5 between the friction ring disks of the friction ring of the brake disk according to DE 10 2016 122 321 A1. This results in considerably better cooling of the friction ring 3 of the brake disk 1 according to the invention.

[0059] The width A of the gap 8 results from the fact that during casting of the brake disk chamber 2 at least a section 3d of a circumferentially closed surface 3c of the inner diameter of the friction ring 3 is used as part of a casting mold 9 used for casting the brake disk chamber 2. The mold 9, which is formed by an upper mold part 9a, a lower mold part 9b and the friction ring 3, is shown in FIGS. 5 and 6. The upper part of the casting mold 9a closes the cavity of the casting mold 9, which is to be filled with melt, by resting on a flat surface or end face 3e of the friction ring 3, in this case the friction ring disk 3a, which is shown the upper friction ring in the illustration. Accordingly, the brake disk chamber 2 is cast onto the connecting elements 4 in a separate casting step.

[0060] The brake disk chamber 2 is produced by means of gravity die casting in a known manner, in which, as mentioned above, in contrast to known solutions, the friction ring 3 or a section 3d of the surface 3c of the inner diameter of the friction ring 3 is used as part of the casting mold 9. During the casting process, the gap 8 is created by the shrinkage of the material used for casting the brake disk chamber 2, preferably an aluminum material.

[0061] FIG. 6 shows a perspective view of the casting mold 9, in which it is clearly visible what is meant by the section 3d of the circumferential surface 3c of the inner diameter of the friction ring 3, which is closed in itself in the circumferential direction and forms part of the casting mold 9, namely that it only takes up a part of the axial extension of the circumferential surface 3c of the inner diameter of the friction ring 3. In FIG. 6, in which the friction ring 3 is shown in a lying manner, this corresponds to a part of the height of the surface area 3c of the inner diameter of the friction ring 3. The section 3d in FIG. 6 is marked by a point hatching and it can be seen that in the present case only the upper friction ring disk 3a forms a part of the casting mold. For example, the section 3d of the surface area 3c of the inner diameter of friction ring 3 may have an axial expansion of 3-20 mm, preferably 5.5-10 mm.

[0062] In a process for manufacturing the brake disk 1, at least a section 3d of the lateral surface 3c of the inner diameter of the friction ring 3 is therefore used as part of the casting mold 9 during casting of the brake disk chamber 3. Furthermore, this process may also provide for the friction ring 3, which is preferably made of grey cast iron, to be heated before casting. The heating causes the friction ring 3 to expand, which leads to a further reduction of the gap 8 as the friction ring 3 contracts again during subsequent cooling.

[0063] To accommodate the connecting elements 4, the friction ring 3 has the respective receiving areas 7 already mentioned above, each of which is provided with bores 10 into which the connecting elements 4 are inserted before casting the brake disk chamber 2. The bores 10 can be designed as blind bores, i.e. they can be designed so that they do not open into one of the cooling channels of the friction ring 3. Such a solution, which prevents water from entering bores 10 and the resulting corrosion problems, can be independent of the other embodiments of the brake disk 1 described herein.

[0064] The connecting elements 4 can, for example, be fastened in the bores 10, which are designed as blind bores, by cooling them down before mounting. In this case, it is also possible to use connecting elements 4 which are slightly flattened on one side so that air can escape when inserting the connecting elements 4 into the bores 10.

[0065] The areas of the brake disk chamber 2 in which it is cast onto the connecting elements 4 are designed as small as possible and as large as necessary to absorb the forces introduced into the brake disk chamber 2 via the friction ring 3 and the connecting elements 4. Due to the described reduction in the size of the connecting elements 4, however, these areas can be designed smaller than with known solutions. The cylindrical shape of the connecting elements 4 described above having no outwardly protruding shoulders or the like allows a further reduction of the areas in which the brake disk chamber 2 is cast around the connecting elements 4.

[0066] FIG. 7 shows a front view of the brake disk 1. It can be seen that it has a considerably larger number of connecting elements 4 than known brake disks. In particular, the number of connecting elements 4 is 21-42, preferably 27-32. In this concrete embodiment, 31 connecting elements 4 are provided. This high number of connecting elements 4 enables the greatly reduced dimensioning of the connecting elements 4 with regard to their diameter and length as described above.

[0067] FIGS. 8 and 9 show another embodiment of the brake disk 1, which also has the brake disk chamber 2, the friction ring 3 and the connecting elements 4 for connecting the brake disk chamber 2 and the friction ring 3.

[0068] In contrast to the embodiment shown in FIGS. 1-7, however, the connecting elements 4 are conical in shape and have a cone angle of 1.6°-3.6°, preferably 1.6°-2.6°, designated “C” in FIG. 9. In this case, the smaller diameter of the connecting elements 4 is located inside the friction ring 3, i.e. the diameter of the connecting elements 4 decreases in the direction from the brake disk chamber 2 towards the friction ring 3, so that an expansion of the friction ring 3 due to heating is possible.

[0069] The conicity of the connecting elements 4 also prevents them from being pulled out of the brake disk chamber 2 when the friction ring 3 expands, as the friction ring 3 can become detached from the connecting elements 4. The connecting elements 4 are preferably conical over their entire length.

[0070] The diameter and length of the connecting elements 4 can correspond to the values described above with regard to the connecting elements 4 of the brake disk 1 according to FIGS. 1-7. The bores 10 of the friction ring 3 of brake disk 1 as shown in FIGS. 8 and 9 can also be blind bores. In the case of the conical connecting elements 4, they can be fitted very easily into the blind bores 10, since the air in the bores 10 can then escape without any problems.

[0071] FIGS. 10 and 11 show further illustrations of the brake disk 1, from which the configuration of the brake disk 1 is more clearly shown, particularly in the receiving areas 7 for the connecting elements 4.

[0072] FIG. 12 shows a very schematic representation of a section of a developed view of the inner diameter of the friction ring of a brake disk according to the invention with the receiving areas 7 of the friction ring 3 for the connecting elements 4. An axial extension of that part of the receiving area 7 of the friction ring 3 which runs from the cooling channel surface 3a2 of the friction ring disk 3a in the direction of the cooling channel 5 is marked “X”. Accordingly, the relevant part of the receiving area 7 for this axial extension “X” is defined as the area of the friction ring 3 that begins at the cooling channel surface 3a2 of the friction ring disk 3a in which the bore 10 for locating the connecting element 4 is located and where the friction ring disk 3a ends or where the connecting web 6 begins. In the present case, this axial extension X is 2-10 mm, preferably 4-7.5 mm, even more preferably 5.5 mm. In FIGS. 2 and 9 the axial extension X of the receiving areas 7 of the friction ring 3, starting from the cooling channel surface 3a2 of the friction ring 3a in the direction of the cooling channel 5, is also indicated. This axial extension X of the receiving areas 7 is comparatively small, which results in an enlarged opening in the cooling channel 5 and allows more cooling air to flow into the same.

[0073] In principle, all the embodiments of the brake disk 1 described herein can be combined with each other in any way, unless there are obvious reasons for not combining them. In particular, it is possible to realize one or more of the features, according to which 21-42, preferably 27-32, connecting elements 4 are provided for connecting the brake disk chamber 2 with the friction ring 3, according to which the connecting elements 4 have a diameter of 3-6.5 mm, preferably 4-5.5 mm, more preferably 5 mm, according to which the connecting elements 4 each have a length of 20-30 mm, preferably 22-26 mm, and/or according to which the connecting elements 4 are conical and have a cone angle of 0.6°-3.6°, preferably 1.6°-2.6°, in a single brake disk 1.