Brake disc for a vehicle

Abstract

The invention relates to a brake disc (2) for a vehicle, which brake disc can be rotated about an axis of rotation (4) and comprises: at least one main body (6); at least one friction layer (8) which is subject to wear, is fixed to the main body (6), and has, on the side facing away from the main body (6), a braking surface (10) against which, when the vehicle is braked, a braking means bears in a contacting manner and so as to produce wear; at least one wear indicator (12) which is located on, at or in the friction layer (8), which is visually perceptible until the friction layer (8) reaches or falls below a critical friction layer thickness at which the friction layer is almost worn away, and which is worn away once the friction layer (8) reaches or falls below the critical friction layer thickness; and at least one position indicator (14) which is associated with a wear indicator (12), is located on the same radial through the axis of rotation (4) as the associated wear indicator (12), is positioned on the same side and surface of the brake disc (2) as the associated wear indicator (12) with respect to the axis of rotation (4), and is always visually perceptible irrespective of the wear of the friction layer (8).

Description

[0001] BRAKE DISC FOR A VEHICLE

[0002] The invention relates to a brake disc for a vehicle.

[0003] When a vehicle is in operation, the brakes, particularly the brake discs, serve to slow the vehicle from one speed to a lower speed. In conventional brake discs, these comprise a base body with a friction layer arranged on one or both sides, against which a braking fluid contacts during braking, causing wear. Over the life cycle of a brake disc, the friction layer is increasingly worn away by abrasion. If the friction layer thickness falls below a critical level, the braking behavior of the brake disc changes, requiring the brake disc to be replaced or reconditioned.

[0004] It is known in the art to measure the thickness of the friction layer in a workshop using a measuring tool, such as a micrometer, to assess during an inspection whether the friction layer is still sufficiently thick or whether the brake disc needs to be replaced. This proves to be cumbersome and time-consuming.

[0005] To avoid the laborious task of measuring with a measuring tool, it is known from the prior art to place a wear indicator on the friction layer, which wears down along with the friction layer during braking. As soon as the wear indicator is no longer visually noticeable because it has been worn down by the numerous braking operations, the brake disc must be replaced or reconditioned.

[0006] During vehicle use, it is never entirely possible for the brake disc to reach a state due to corrosion or contamination that makes the wear indicator unreadable or difficult to detect visually, for example, because it is clogged with corrosion or particles. In such cases, a brake disc may be mistakenly assessed as worn.

[0007] An object of an embodiment of the invention is to propose a brake disc in which an inspection of the brake disc is simplified.

[0008] This object is achieved by a brake disc for a vehicle, which is rotatable about an axis of rotation, with at least one base body, with at least one friction layer subject to wear, which is fixed to the base body and which has a braking surface on the side facing away from the base body, against which a braking medium contacts and generates wear when the vehicle is braked, with at least one wear indicator arranged on, at or in the friction layer, which is visually perceptible until a critical friction layer thickness of the friction layer is reached or undershot, at which the friction layer is almost worn away, and which is worn away once the critical friction layer thickness of the friction layer is reached or undershot, and with at least one position indicator assigned to a wear indicator arranged on the same radial line through the axis of rotation as the assigned wear indicator,which is arranged on the same side and surface of the brake disc as the associated wear indicator with respect to the axis of rotation and which is always visually perceptible regardless of the wear of the friction layer.

[0009] The brake disc incorporates a position indicator that is associated with a wear indicator and is always visible, simplifying and improving the process of finding and checking whether the wear indicator is still visible. The position indicator shows the line on which the wear indicator is located—namely, the radial line through the rotational axis.

[0010] This allows for a quick visual assessment of whether the wear indicator is still visible and, if in doubt, the brake disc can be cleaned along the radial line relative to the position indicator to rule out possible non-visibility due to existing contamination or a clogging of the wear indicator. This optimizes the time required to check a brake disc for roadworthiness. The base body and friction layer can form a single, integral component and, in this case, be made of gray cast iron, for example. The critical friction layer thickness can range from 20 to 100 μm.

[0011] The base body and friction layer can comprise components that are joined together or joined to one another. In this case, the brake disc comprises a coated brake disc, in which the base body comprises the friction layer as an additional, subsequently applied coating. The critical friction layer thickness for coated brake discs can be 20 μm.

[0012] If the friction layer of a coated brake disc is completely worn away, the braking behavior changes in an unfavorable way.

[0013] In one embodiment of the brake disc, it proves to be advantageous if the base body has a surface section that is uncoated or coated with a transparent material, which is arranged between the axis of rotation and the friction layer and which, when the vehicle is braking, is spaced apart from the wear-generating braking means in a contact-free manner, wherein at least one of the at least one position indicator is arranged on the surface section that is uncoated or coated with a transparent material.

[0014] By locating the position indicator on an uncoated or transparently coated surface section of the base body, located between the rotation axis and the friction layer, the position indicator is protected from wear caused by abrasion during braking. This ensures that the position indicator is always visually perceptible, regardless of wear on the friction layer.

[0015] In a further development of the latter embodiment, it is provided that the uncoated surface section or the surface section coated with a transparent material, on which at least one of the at least one position indicator is arranged, runs parallel, obliquely or transversely to the friction layer.

[0016] The position indicator on the uncoated surface section or the surface section coated with a transparent material can, in principle, be designed in any desired manner. Embodiments of the brake disc are provided in which at least one of the at least one position indicator comprises an additional coating on the uncoated surface section or the surface section coated with a transparent material, or in which at least one of the at least one position indicator comprises a recess in the uncoated surface section or the surface section coated with a transparent material.

[0017] If the position indicator includes an additional coating, the position indicator can be raised relative to the surface section. This reduces the risk of the position indicator becoming clogged with dirt.

[0018] If the position indicator includes a recess in the surface section, the brake disc can be designed with reduced components.

[0019] The surface portion may be uncoated or coated with a transparent material. The transparent material may, for example, comprise a corrosion protection agent or the like.

[0020] In a further development of the latter embodiments, it proves to be advantageous if the position indicator formed by additional coating of the uncoated surface section or surface section coated with a transparent material comprises a coating or laser deposition welding.

[0021] If the position indicator includes a coating, this can be simply applied and visually separated from the surface section. If the position indicator is applied to the surface section using laser deposition welding, the position indicator can, for example, be applied in the same machining process as the friction layer. The friction layer can also be applied to the base body using laser deposition welding.

[0022] Furthermore, the position indicator can be produced during the manufacturing process of the base body, in particular during a casting process.

[0023] If the position indicator comprises a recess in the surface section, this can be achieved, for example, by milling, eroding, or using a laser. The position indicator can, in principle, comprise any contour in any cross-section. It is advantageous if at least one of the at least one position indicator comprises an angular, in particular triangular or square, a rounded, in particular circular or elliptical, a point-like, a line-like, or an arrow-like contour with respect to the surface section comprising the position indicator.

[0024] If the position indicator comprises, for example, a line-like, angular, especially triangular, or arrow-like contour, the position indicator can also provide a direction indication pointing to the wear indicator. This is also ensured if the position indicator is line-like.

[0025] Alternatively or in addition to the arrangement of the position indicator on the surface section, the position indicator can comprise a recess on the base body and / or in the friction layer that projects in the direction of the axis of rotation, which recess is arranged on the circumference of the brake disc facing away from the axis of rotation and which is open to the outside on the side of the brake disc facing away from the axis of rotation.

[0026] This makes it easy to create a position indicator on the side of the brake disc facing away from the axis of rotation.

[0027] In a further development of the latter embodiment, it proves to be advantageous if the recess forming the position indicator comprises a triangular, square or arcuate cross-section transverse to the axis of rotation and comprises a wedge-like, cuboid-like or groove-like contour.

[0028] By forming the recess with a triangular, square, or arcuate cross-section, a direction indicator can be created in addition to the position indicator. This further improves the detectability of the wear indicator.

[0029] The brake disc can be manufactured more easily in terms of components and manufacturing technology if the recess in the base body forming the position indicator, or if the depression in the base body and / or in the friction layer forming the position indicator, is free of material. This eliminates the need for an additional process step for filling the recess or depression. Furthermore, no filler material needs to be stored.

[0030] If the recess is formed without material, it appears notch-like.

[0031] In order to reduce the risk of the recess and / or the depression becoming clogged with particles, one embodiment of the brake disc provides that the recess forming the position indicator in the base body or that the depression forming the position indicator in the base body and / or the friction layer is arranged with a display element of the position indicator, which comprises a transparent or opaque material that is optically distinguishable from the base body or from the friction layer.

[0032] If the indicator element comprises a transparent or opaque material that is visually distinguishable from the base body or the friction layer, the risk of the recess or depression becoming clogged with particles, such as dirt, is reduced. Furthermore, this can ensure continued detectability of the position indicator.

[0033] In principle, it is conceivable for the indicator element to be inserted into the recess and / or the depression and glued there. However, it is advantageous if the indicator element is cast into the base body and / or the friction layer.

[0034] If the indicator element is cast into the base body and / or the friction layer, for example, the indicator element can be worn and eroded during the material-wearing braking processes of the brake disc. However, because the indicator element is also arranged in the recess or recess of the base body, the indicator element and thus the position indicator are still visually perceptible even if the friction layer is completely eroded.

[0035] When mounted on a vehicle, the brake disc rotates with a wheel unit of the vehicle. During braking, the braking fluid therefore sweeps over a flat area of ​​the friction layer of the brake disc due to the rotation of the brake disc about its axis of rotation, wearing this material down essentially evenly. It is therefore generally sufficient for the brake disc to have only a single wear indicator and at least one position indicator associated with the wear indicator. In order to make it easier to detect whether the friction layer of the brake disc is above the critical friction layer thickness, it is advantageous if at least three wear indicators are arranged on, at, or in each friction layer, and if each wear indicator is associated with at least one position indicator.

[0036] In a further development of the latter embodiment, it proves to be advantageous if the wear indicators and the position indicators assigned to the respective wear indicator are arranged at the same or different angles to each other with respect to the axis of rotation, evenly or unevenly distributed on, at or in the friction layer.

[0037] Finally, in one embodiment of the brake disc, a friction layer with at least one wear indicator and at least one position indicator associated with the wear indicator is arranged on each surface of the base body running transversely to the axis of rotation.

[0038] In this case, the brake disc comprises a friction layer on both sides of the base body. By providing separate wear indicators and position indicators for each friction layer, the friction layers can be assessed independently of each other to determine whether the remaining friction layer thickness is above the critical friction layer thickness.

[0039] The friction layer can comprise any desired material. Preferred embodiments of the brake disc are those in which the friction layer comprises a stainless steel, an oxide, such as a ceramic-metal composite, or a carbide with a friction layer thickness of 100 μm to 300 μm, or a stainless steel with a friction layer thickness of 100 μm to 1.5 mm.

[0040] Further features, details and advantages of the invention emerge from the appended patent claims, from the drawings and the following description of two preferred embodiments of the brake disc.

[0041] The drawing shows: Figure 1 a plan view and a sectional view along the line AA through a first embodiment of the brake disc;

[0042] Figure 2 A plan view and a sectional view along the line AA through a second embodiment of the brake disc.

[0043] Figures 1 and 2 each show different embodiments of a brake disc for a vehicle, designated overall by the reference numeral 2. The brake disc 2 is rotatable about a rotation axis 4.

[0044] The brake disc 2 comprises a base body 6 which, in the embodiments shown in the figures, is provided on both sides with a friction layer 8 which is subject to wear and which is fixed to the base body 6 as an applied additional layer.

[0045] The friction layers 8 each comprise a braking surface 10 on their side facing away from the base body 6. When the vehicle brakes, a braking agent (not shown in the figures) is in contact with the braking surface 10, causing wear, to brake the vehicle. When the vehicle brakes, the friction layer 8 is worn away and, over its life cycle, decreases from an initial friction layer thickness to a critical friction layer thickness at which the friction layer is almost completely worn away.

[0046] In order to indicate whether the friction layer thickness of the friction layer 8 is still sufficient, the brake disc 2 in the exemplary embodiments shown in the figures comprises three wear indicators 12 which are arranged on, at or in the respective friction layer 8, which are visually perceptible until a critical friction layer thickness of the friction layer 8 is reached or fallen below, at which the friction layer is almost worn away, and which is worn away once the critical friction layer thickness of the friction layer 8 is reached or fallen below.

[0047] In addition, in the embodiments shown in the figures, the brake disc 2 comprises three position indicators 14 on each brake disc 2, each of which is assigned to a wear indicator 12, which are arranged on the same radial through the axis of rotation 4 as the assigned wear indicator 12, which is arranged on the same side and surface of the brake disc 2 as the assigned wear indicator 12 with respect to the axis of rotation 4 and which are always visually perceptible regardless of the wear of the friction layer 8.

[0048] Figure 1 shows a first embodiment of the brake disc 2, in which the position indicators 14 are arranged on a surface section 16 of the base body 6, either uncoated or coated with a transparent material. In the embodiment shown in Figure 1, this section comprises an arrangement in which it runs obliquely to the friction layer 8. The surface section 16, which is uncoated or coated with a transparent material, is arranged between the rotation axis 4 and the friction layer 8 and, when the vehicle is braking, is spaced apart from the wear-generating braking medium without contact.

[0049] Figure 1 shows an embodiment of the brake disc 2 in which the position indicator 14 comprises an additional coating and an arrow-like contour pointing in the direction of the wear indicator 12.

[0050] Figure 2 shows a second embodiment of the brake disc 2, in which the position indicator 14 is formed by a recess 18 projecting in the direction of the rotation axis 4 on the base body 6 and in the friction layer 8, which is arranged on the circumference of the brake disc 2 facing away from the rotation axis 4. The recess 18 is open to the outside on the side of the brake disc 2 facing away from the rotation axis 4.

[0051] In the embodiment shown in Figure 2, the recess 18 is formed without material, in this case notch-like.

[0052] The features of the invention disclosed in the above description, in the claims, and in the drawings may be essential, both individually and in any combination, for the realization of the invention in its various embodiments. List of reference symbols

[0053] 2 brake discs

[0054] 4 Rotation axis 6 Base body

[0055] 8 Friction layer

[0056] 10 braking surface

[0057] 12 Wear indicator

[0058] 14 Position indicator 16 Surface section

[0059] 18 Deepening

Claims

P a t e n t a n s p r ü c h e 1. Brake disc (2) for a vehicle, rotatable about an axis of rotation (4), comprising at least one base body (6), comprising at least one wear-prone friction layer (8) fixed to the base body (6) and having a braking surface (10) on the side facing away from the base body (6), against which a braking medium makes contact and causes wear when the vehicle is braked, comprising at least one wear indicator (12) arranged on, at or in the friction layer (8), which is optically perceptible until a critical friction layer thickness of the friction layer (8) is reached or fallen below, at which point the friction layer is almost worn away, and which is worn away once the critical friction layer thickness of the friction layer (8) is reached or fallen below, and comprising at least one position indicator (14) associated with a wear indicator (12) arranged on the same radial line through the axis of rotation (4) as the associated wear indicator (12),which is located on the same side and surface of the brake disc (2) with respect to the axis of rotation (4) as the associated wear indicator (12) and which is always visually perceptible regardless of the wear of the friction layer (8).

2. Brake disc (2) according to claim 1, characterized in that the base body (6) has an uncoated or transparently coated surface section (16) which is arranged between the axis of rotation (4) and the friction layer (8) and which is spaced apart from the wear-inducing brake fluid during braking of the vehicle, wherein at least one of the at least one position indicator (14) is arranged on the uncoated or transparently coated surface section (16).

3. Brake disc (2) according to claim 2, characterized in that the uncoated or coated surface section (16) on which at least one of the at least one position indicator (14) is arranged runs parallel, obliquely or transversely to the friction layer (8).

4. Brake disc (2) according to one of the preceding claims, characterized in that at least one of the at least one position indicator (14) comprises an additional coating of the uncoated or transparently coated surface section (16) or that At least one of the at least one position indicator (14) comprises a recess in the uncoated or transparently coated surface section (16). Brake disc (2) according to claim 4, characterized in that the position indicator (14) formed by additional coating of the uncoated or transparently coated surface section (16) comprises a coating or laser cladding. Brake disc (2) according to any one of the preceding claims, characterized in that at least one of the at least one position indicator (14) comprises, with respect to the surface section (16) comprising the position indicator (14), an angular, in particular triangular or quadrilateral, a rounded, in particular circular or elliptical, a dot-like, a line-like, or an arrow-like contour.A brake disc (2) according to one of the preceding claims, characterized in that the position indicator (14) comprises a recess (18) projecting towards the axis of rotation (4) on the base body (6) and / or in the friction layer (8), which is arranged on the circumference of the brake disc (2) facing away from the axis of rotation (4) and which is open to the outside on the side of the brake disc (2) facing away from the axis of rotation (4). A brake disc (2) according to claim 7, characterized in that the recess (18) forming the position indicator (14) has a triangular, quadrilateral, or arcuate cross-section transverse to the axis of rotation (4) and comprises a wedge-shaped, cuboid, or groove-like contour. Brake disc (2) according to one of claims 4 to 8, characterized in that the recess forming the position indicator (14) in the base body (6) or that the depression (18) forming the position indicator (14) in the base body (6) and / or the friction layer (8) is material-free.brake disc (2) according to one of claims 4 to 8, characterized in that the recess forming the position indicator (14) in the base body (6) or that the depression (18) forming the position indicator (14) in the base body (6) and / or the friction layer (8) is a display element of the position indicator (14). The brake disc (2) according to claim 10 comprises a transparent or opaque material that is optically distinguishable from the base body (6) or the friction layer (8). The brake disc (2) according to claim 10 is characterized in that the indicator element is cast into the base body (6) and / or into the friction layer (8). The brake disc (2) according to any of the preceding claims is characterized in that at least three wear indicators (12) are arranged on, at, or in each friction layer (8), and that at least one position indicator (14) is assigned to each wear indicator (12). The brake disc (2) according to claim 12 is characterized in that the wear indicators (12) and the position indicators (14) assigned to each wear indicator (12) are arranged on, at, or in the friction layer (8) at equal or different angles to each other, evenly or unevenly distributed.Brake disc (2) according to one of the preceding claims, characterized in that a friction layer (8) with at least one wear indicator (12) and at least one position indicator (14) associated with the wear indicator (12) is arranged on each surface of the base body (6) extending transversely to the axis of rotation (4). Brake disc (2) according to one of the preceding claims, characterized in that the friction layer (8) comprises a stainless steel, an oxide, such as a ceramic-metal composite material, or a carbide with a friction layer thickness of 100 pm to 300 pm or a stainless steel with a friction layer thickness of 100 pm to 1.5 mm.

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