brake disc

Abstract

Brake disc (1) with a brake disc hub (2), with a friction ring (3) having two friction ring discs (3a, 3b) and with several pin-shaped connecting elements (4) received in respective bores (8) of receiving areas (7) of the friction ring (3) for connecting the brake disc hub (2) to the friction ring (3), wherein the receiving areas (7) are directly attached to only one of the two friction ring discs (3a), wherein a cooling channel (5) is formed between the friction ring discs (3a, 3b), and wherein connecting webs (6) connecting the friction ring discs (3a, 3b) to each other are located within the cooling channel (5), wherein the connecting webs (6) extend away from the receiving areas (7) and extend from a radially outer end of the bores (8) of the receiving areas (7) over the bores (8) of the receiving areas (7) for a maximum of one-third of the length of the bores (8) of the receiving areas (7), characterized in thatthat, starting from the receiving areas (7), at least one column-like support element (9a, 9b) extends away from the respective connecting web (6) and does not extend over the bore (8) for the most part to the other friction ring disc (3b).

Description

[0001] The invention relates to a brake disc with a brake disc chamber, with a friction ring having two friction ring discs and with a plurality of pin-shaped connecting elements received in respective bores of receiving areas of the friction ring for connecting the brake disc chamber to the friction ring according to the type defined in more detail in the preamble of claim 1.

[0002] A brake disc of this type is known from DE 10 2006 043 945 A1. The brake disc hub is connected to the friction ring by means of several connecting elements arranged around its circumference and extending in a radial direction. The receiving areas for the connecting elements, which have suitable bores, are attached directly to only one of the two friction ring discs, so that the center axes of the connecting elements are offset from the center of the friction ring in the axial direction of the latter. A cooling channel is formed between the friction ring discs, within which connecting webs are located that interconnect the friction ring discs. These webs also extend into an area above the bores for the connecting elements.

[0003] A similar brake disc is also known from DE 10 2016 122 321 A1. This document describes, among other things, a variety of embodiments of the connecting element used to connect the brake disc chamber to the friction ring.

[0004] A further development of the composite brake discs described above is known from the generic EP 3 712 459 B1. The distance between the brake disc chamber and the outer surface at the inner diameter of the friction ring is narrower than is the case with conventional composite brake discs, which leads to better flow through the cooling channel formed between the friction ring discs.

[0005] DE 10 2010 024 389 A describes a connecting device between a friction ring and a brake disc chamber of a brake disc, wherein the friction ring is connected to the brake disc chamber via several connecting elements. The connecting elements, distributed around the circumference of the brake disc chamber and connected to it, extend into recesses in a radially inner circumferential wall of the friction ring. The bores in the friction ring and the connecting elements are conical.

[0006] DE 10 2009 002 690 A1 describes another brake disc with two friction rings and a disc hub connected to the friction rings via connecting elements. A support web is formed between the two friction rings, in which there are annular recesses.

[0007] DE 10 2008 044 339 B4 discloses a brake disc assembly for disc brakes comprising a friction ring, a connection adapter for connecting the brake disc assembly to a wheel hub, and a plurality of connecting elements for connecting the friction ring to the connection adapter. The connection adapter has a fastening region in which the connecting element is fixedly fastened and which is designed as a recess extending radially from the outer circumference of the connection adapter into the latter. Furthermore, the connection adapter has a radial recess for air circulation, which extends from the inner circumference of the connection adapter to its fastening region for the connecting element. The friction ring has a receiving region in which the connecting element is received such that the friction ring is radially movable relative to the connecting element.

[0008] DE 101 03 639 A1 describes connecting elements designed as hollow pins, which are intended to enable improved cooling of the friction ring.

[0009] A ventilated brake disc with a friction ring and a supporting part, in which several connecting parts connected to the supporting part are present on the circumference of the supporting part and project into extensions formed on the friction ring, is known from DE 10 2007 054 393 A1.

[0010] EP 2 337 967 B1 describes another ventilated brake disc with a friction ring consisting of at least two friction ring discs separated by webs, and a support member, on the circumference of which several connecting parts are connected to the friction ring and extend into support webs formed on the friction ring. The support webs are arranged between the friction rings and have a gap between them and the friction ring discs. However, due to the central arrangement of the support webs, only a limited amount of cooling air can flow into the cooling channel of the friction ring.

[0011] DE 10 2013 215 997 A1 describes a brake disc for a disc brake comprising a brake disc chamber and a friction ring connected to the chamber via connecting means. A casing of the brake disc chamber is provided with sections of reduced wall thickness and / or perforations formed as axially directed material recesses located on the outer circumference of the brake disc chamber casing. These recesses serve to position the connecting means as close as possible to the brake disc chamber casing.

[0012] Another brake disc is described in DE 10 2009 021 852 A1. This brake disc comprises a brake disc hub and a friction ring connected to each other via pin-shaped connecting elements. The connecting elements are inserted into the brake disc hub, widening an axially extending through-hole.

[0013] A brake disc with a friction ring and a brake disc chamber connected by such connecting elements is also described in DE 198 43 399 A1. One wall of the brake disc chamber is designed to be resilient in the radial direction.

[0014] Further connecting elements, which are manufactured integrally and in one piece with the friction ring and are wedge-shaped on the side received in the friction ring, are described in EP 2 275 702 B1.

[0015] GB 1 032 923 A describes a brake disc whose friction ring is cast onto the guide surfaces of a hub body in such a way that, in the event of a temperature increase and a consequent enlargement of the friction ring, a radial movement of the same relative to the brake disc chamber is possible.

[0016] DE 199 18 667 A1 discloses a brake disc for a vehicle disc brake, comprising a cup section and a friction ring section with two friction rings connected to each other via webs. The cup and friction ring sections interlock in such a way that a positive fit is achieved in the axial and circumferential directions and limited displacement in the radial direction.

[0017] US 5,862,892 A describes a composite rotor for disc brakes which has an outer friction portion with two ring portions, an inner hub part with a central mounting portion, and a peripheral portion which is cast into a cavity of the outer friction portion.

[0018] DE 20 2007 009 345 U1 shows a brake disc with radial, elongated cooling fins and further cooling fins arranged between the same and the inner edge of the brake disc and spaced from the radial cooling fins.

[0019] During braking, the friction ring in conventional brake discs deforms due to the high forces acting on it, causing the bore accommodating the pin-shaped connecting element to deform from its original circular shape into an oval shape. This creates tensile stresses, which are further amplified by the arrangement of the connecting webs above the bores and the resulting force acting on the bores.

[0020] With these composite brake discs, the difficulty also regularly arises that the air flow from the inside of the vehicle to the opening of the brake disc chamber in the cooling channel of the brake disc is only possible to a limited extent.

[0021] It is therefore an object of the present invention to provide a brake disc with a brake disc chamber, with a friction ring having two friction ring discs and with a plurality of pin-shaped connecting elements received in respective bores of receiving areas of the friction ring for connecting the brake disc chamber to the friction ring, in which there is a lower load on the bores serving to receive the pin-shaped connecting elements.

[0022] According to the invention, this object is achieved by the features mentioned in claim 1.

[0023] In the brake disc according to the invention, the connecting webs connecting the friction ring discs of the friction ring to one another extend, starting from a radially outer end of the bores of the receiving areas, over the bores of the receiving areas by a maximum of one third of the length of the bores of the receiving areas, so that the loads emanating from these connecting webs on the bores or on the receiving areas in which the bores are located are significantly reduced.

[0024] Furthermore, the brake disc according to the invention has at least one column-like support element spaced from the respective connecting web and at least predominantly not extending beyond the bore. This support element runs from the respective receiving area to the friction ring disc to which the receiving area is not connected. This at least one column-like support element, which is arranged between the receiving area and the opposite friction ring disc, ensures sufficient support of the two friction ring discs against each other while still guaranteeing sufficient transmission of the cooling air from the brake disc chamber into the cooling channel formed between the friction ring discs.Because the column-like support element does not extend, at least for the most part, over the bore used to receive the pin-shaped connecting element, the latter is relieved of pressure by the thermal deformation of the friction ring that occurs during the braking process, which ultimately leads to significantly lower stresses in the bores and the receiving areas.

[0025] In a very advantageous development of the invention, it can be provided that the at least one column-like support element extends across the bore by a maximum of one-third of the diameter of the bore. In this way, the bore used to accommodate the pin-shaped connecting element is sufficiently relieved of pressure, resulting in lower stresses in the bores and the receiving areas.

[0026] In a further very advantageous development of the invention, two columnar support elements, spaced from the respective connecting web and at least predominantly not extending beyond the bore, extend from the receiving areas to the other friction ring disc. This leads to a significant improvement in the stability of the brake disc.

[0027] In order to further improve the introduction of cooling air into the cooling channel, a further advantageous embodiment of the invention can provide for a passage opening to the cooling channel between the two column-like support elements.

[0028] A further embodiment of the invention may consist in the at least one columnar support element running substantially parallel to a rotational axis of the brake disc. This has led to improved results regarding the strength of the brake disc.

[0029] In order to achieve an improvement both with regard to the stability between the friction ring discs and with regard to the introduction of cooling air into the cooling channel between them, it can further be provided that the at least one column-like support element has a drop-shaped, rhombus-shaped or circular cross-section, wherein a drop-shaped cross-section has proven to be particularly advantageous with regard to facilitating the inflow of cooling air into the cooling channel of the brake disc.

[0030] In the following, embodiments of the invention are shown in principle with reference to the drawing.

[0031] It shows: Fig. 1 a perspective view of a first embodiment of the brake disc according to the invention; Fig. 2 an enlarged section of the brake disc Fig. 1 with a representation of the connecting webs and the column-like support elements; Fig. 3 a sectional view of the brake disc from Fig. 1; Fig. 4 a section along the line IV-IV Fig. 2; Fig. 5 a section along the line VV Fig. 3; Fig. 6 a perspective view of a second embodiment of the brake disc according to the invention; Fig. 7 an enlarged section of the brake disc Fig. 6 with a representation of the connecting webs and the column-like support elements; Fig. 8 a sectional view of the brake disc from Fig. 6; Fig. 9 a section along the line IX-IX Fig. 7; and Fig. 10 a section along the line XX Fig. 8.

[0032] Fig. 1 shows an internally ventilated brake disc 1 designed as a composite brake disc, which, in a conventional manner, has a central brake disc chamber 2, around whose circumference a friction ring 3 is arranged. The friction ring 3 has two friction ring discs 3a and 3b and is connected to the brake disc chamber 2 by means of several pin-shaped connecting elements 4 extending in the radial direction from the brake disc chamber 2 to the friction ring 3. The friction ring 3 is slidably mounted on the pin-shaped connecting elements 4, whereby it can expand radially unhindered and freely during thermal loading of the brake disc 1 and is therefore less susceptible to cracking.

[0033] On their outer flat surfaces, the friction ring discs 3a and 3b each have only Fig. 3 and Fig. 8 designated friction surfaces 3a1 and 3b1. Between the friction ring discs 3a and 3b, a cooling channel 5 is formed, through which cooling air can flow from the direction of the brake disc chamber 2 through the friction ring 3 to the outside of the brake disc 1 during operation of the brake disc 1 in a manner known per se. Within the cooling channel 5 there are several connecting webs 6, by means of which the friction ring discs 3a and 3b are connected in a manner also known per se or on which the friction ring discs 3a and 3b are supported. The connecting webs 6 absorb the forces acting on the friction ring discs 3a and 3b under load, for example during a braking operation. Furthermore, the friction ring 3 has several receiving areas 7 for receiving the pin-shaped connecting elements 4. The receiving areas 7 are attached directly to only one of the two friction ring discs, in the present case to the friction ring disc 3a, i.e.They are not directly connected to the other friction ring disc 3b. This connection of the receiving areas 7 to the friction ring disc 3a occurs during the casting of the friction ring 3, in that the receiving areas 7 are also cast during the casting of the friction ring 3, which in turn is achieved by a corresponding design of the casting mold (not shown).

[0034] The brake disc chamber 2 forms, in a manner known per se, the connection between the brake disc 1 and a chassis (not shown) of a motor vehicle equipped with the brake disc 1. Furthermore, respective brake pads (also not shown in the figures) engage the friction ring 3 in a manner known per se in order to achieve a desired deceleration of the motor vehicle. The pin-shaped connecting elements 4 transfer the braking torque acting on the friction ring 3 to the brake disc chamber 2 and thus to the motor vehicle. The pin-shaped connecting elements 4 are therefore exposed to very high loads, and it is essential for the effectiveness of the brake disc that the pin-shaped connecting elements 4 remain intact. The same applies to the receiving areas 7 in which the pin-shaped connecting elements 4 are received.

[0035] To accommodate the pin-shaped connecting elements 4, the above-mentioned receiving areas 7 are provided with respective bores 8 into which the pin-shaped connecting elements 4 are inserted before, in a subsequent step, the brake disc chamber 2 is cast onto the pin-shaped connecting elements 4 and thus onto the friction ring 3. In the present case, the bores 8 are designed as through bores opening into one of the cooling channels 5 of the friction ring 3, but they can also be designed as blind bores, i.e. they can be designed such that they do not open into one of the cooling channels 5 of the friction ring 3. Such a solution, which prevents water from entering the bores 8 and the resulting corrosion problems, can be independent of the other embodiments of the brake disc 1 described herein.

[0036] Those areas of the brake disc chamber 2 in which it is cast onto the pin-shaped connecting elements 4 are designed to be as small as possible and as large as necessary to absorb the forces introduced into the brake disc chamber 2 via the friction ring 3 and the pin-shaped connecting elements 4.

[0037] In order to prevent the connecting webs 6 from exerting excessive stress on the receiving areas 7 and in particular on the bores 8 in which the pin-shaped connecting elements 4 are arranged, the connecting webs 6 extend at least not completely over the bores 8 of the receiving areas 7. In general, the connecting webs 6 extend, starting from a radially outer end of the bores 8 of the receiving areas 7, i.e. from the end thereof facing away from the brake disk chamber 2, over the bores 8 of the receiving areas 7 for a maximum of one-third of the length of the bores 8 of the receiving areas 7. In the present case, the connecting webs 6 extend, starting from a radially outer end of the bores 8 of the receiving areas 7, over the bores 8 of the receiving areas 7 for a maximum of one-fifth of the length of the bores 8 of the receiving areas 7.In other words, the connecting webs 6 are significantly shortened in the radial direction compared to the solutions known from the prior art, in which they run almost to the inner edge of the friction ring 3.

[0038] In addition, at least one, in the present case two, column-like support elements 9a and 9b are provided, which extend from the receiving area 7 connected to one friction ring disk 3a to the other friction ring disk 3b. The at least one column-like support element 9a or 9b is spaced from the respective connecting web 6 and at least for the most part does not extend over the bore 8. In particular, the at least one column-like support element 9a or 9b, or in the present case both maximum column-like support elements 9a and 9b, extends over the bore 8 for one-third of the diameter of the same. The bore 8 is therefore essentially free of the connecting webs 6 and the at least one column-like support element or the column-like support elements 9a and 9b.In this way, the introduction of force into that region of the receiving areas 7 in which the bore 8 is located and which is already weakened by the bore 8 is avoided. The at least one column-like support element 9a or 9b therefore represents a kind of continuation of the connecting web 6, but it is ensured that a lower pressure is applied to the bore 8 of the receiving area 7 compared to known solutions with a continuous connecting web.

[0039] In this case, one or first columnar support element 9a is arranged on a first side wall 7a of the receiving area 7, and the other or second columnar support element 9b is arranged on an opposite side wall 7b of the receiving area 7. This arrangement directs the forces acting between the friction ring discs 3a and 3b on the columnar support elements 9a and 9b via the side walls 7a and 7b of the connecting area 7 and not via the bore 8 located therein.

[0040] As already mentioned, the Fig. 1 to 5, two column-like support elements 9a and 9b, spaced from the respective connecting web 6, extend from the receiving area 7 connected to the friction ring disc 3a to the other friction ring disc 3b, which at least for the most part do not extend beyond the bore 8. Furthermore, it can be seen in the figures that between the two column-like support elements 9a and 9b there is a passage opening 10 to the cooling channel 5, so that the air from the brake disc chamber 2 can pass past the column-like support elements 9a and 9b into the cooling channel 5.

[0041] The at least one column-like support element, in the present case both column-like support elements 9a and 9b, run essentially parallel to a Fig. 3 axis of rotation of the brake disc 1 marked “x”.

[0042] In the cut of Fig. 5 shows that the at least one columnar support element, or in the present case both columnar support elements 9a and 9b, has a drop-shaped or egg-shaped cross-section. Alternatively, it would also be possible to design the columnar support elements 9a and / or 9b with a rhombus-shaped, circular, or other suitable cross-section. In principle, it is also conceivable for the cross-section of the columnar support element 9a or 9b to change over the length of its extension from the receiving area 7 to the friction ring disc 3b.

[0043] A second embodiment of the brake disc 1 is described below with reference to Fig. 6 to 10, only the differences compared to the first embodiment of the brake disc 1 according to the Fig. 1 to 5. However, these differences do not affect the column-like support elements 9a and 9b.

[0044] In the embodiment of the brake disc 1 according to the Fig. 6 to 10, the pin-shaped connecting elements 4 are essentially cylindrical and have a diameter of 3 - 6.5 mm. The length of the pin-shaped connecting elements 4 is Fig. 6 to 10 illustrated embodiment of the brake disc 1 20 - 30 mm.

[0045] In the perspective view of the brake disc 1 according to Fig. 6 shows that this brake disc has a significantly larger number of pin-shaped connecting elements 4 than known brake discs. In particular, there are 21-42, preferably 27-32, pin-shaped connecting elements 4. This high number of pin-shaped connecting elements 4 enables the above-described significantly reduced dimensioning of the pin-shaped connecting elements 4 with regard to their diameter and length.

[0046] In the first embodiment of the brake disc 1 according to Fig. 1 to 5, there is an unspecified gap between the brake disc chamber 2 and the friction ring 3, which is comparatively large and through which a large amount of the cooling air required for cooling the friction ring 3 through which air can flow as described above can flow out and can therefore lead to a strong heating of the friction ring 3.

[0047] In contrast, the gap between the brake disc chamber 2 and the friction ring 3 in the brake disc 1 according to the Fig. 6 to 10 have a significantly smaller width than usual. This allows less air to flow through the gap, and more air enters the cooling channel 5 located between the friction ring discs 3a and 3b of the friction ring 3, so that the friction ring 3 is more effectively cooled.

Claims

[1] Brake disc (1) with a brake disc chamber (2), with a friction ring (3) having two friction ring discs (3a, 3b), and with a plurality of pin-shaped connecting elements (4) received in respective bores (8) of receiving areas (7) of the friction ring (3) for connecting the brake disc chamber (2) to the friction ring (3), wherein the receiving areas (7) are directly attached to only one of the two friction ring discs (3a), wherein a cooling channel (5) is formed between the friction ring discs (3a, 3b), and wherein connecting webs (6) connecting the friction ring discs (3a, 3b) to one another are located within the cooling channel (5), wherein the connecting webs (6) extend away from the receiving areas (7) and, starting from a radially outer end of the bores (8) of the receiving areas (7), extend over the bores (8) of the receiving areas (7) by a maximum of one third of the length of the bores (8) of the receiving areas (7). extend, characterized bythat, starting from the receiving areas (7), at least one column-like support element (9a, 9b) which is spaced from the respective connecting web (6) and at least predominantly does not extend over the bore (8) extends to the other friction ring disc (3b). [2] Brake disc according to claim 1, characterized by that the at least one column-like support element (9a, 9b) extends over the bore (8) to a maximum of one third of the diameter thereof. [3] Brake disc according to claim 1 or 2, characterized by that from the receiving areas (7) two column-like support elements (9a, 9b) spaced from the respective connecting web (6) and at least predominantly not extending over the bore (8) extend to the other friction ring disc (3b). [4] Brake disc according to claim 3, characterized bythat between the two column-like support elements (9a,9b) there is a passage opening (10) to the cooling channel (5). [5] Brake disc according to one of claims 1 to 4, characterized by that the at least one column-like support element (9a, 9b) runs substantially parallel to an axis of rotation (x) of the brake disc (1). [6] Brake disc according to one of claims 1 to 5, characterized by that the at least one column-like support element (9a, 9b) has a drop-shaped, rhombus-shaped or circular cross-section.

Images