Drum brake for a vehicle

Abstract

The invention relates to a drum brake (2) for a vehicle, comprising at least one brake drum (6) mounted for rotation about a rotation axis (4), comprising at least one planar armature plate (8) which is rotationally fixed with respect to the rotation axis (4), wherein the armature plate (8) and the brake drum (6) are spaced apart from one another by a gap (10) without contact and surround a cavity (12), comprising at least one brake medium holder (14) arranged in the cavity (12) and movably secured to the armature plate (8), comprising at least one brake medium (16) which is secured to the brake medium holder (14) on the side of the brake medium holder (14) facing the brake drum (6) and which has a friction layer (20) forming a braking surface (18) which, in a braking position, bears against a contact surface (22) of the brake drum (6) in contact with the braking surface (18) and producing wear, and comprising at least one magnetic means (26),by which magnetic or magnetizable brake dust (24) can be magnetically attracted, wherein at least one of the at least one magnetic means (26) is arranged outside the cavity (12) on the planar anchor plate (8) on a side facing away from the brake drum (6) and / or wherein at least one of the at least one magnetic means (26) is arranged within the cavity (12) on the planar anchor plate (8) on a side facing the brake drum (6).

Description

[0001] The invention relates to a drum brake for a vehicle.

[0002] When a motor vehicle is operating, particularly when braking, a brake fluid in a drum brake is moved toward the brake drum. The brake fluid rests against the brake drum with a friction layer comprising a braking surface.

[0003] Due to the prevailing friction between the brake fluid and the brake drum, it can never be completely prevented that particles from the friction layer of the brake fluid or from the inner surface of the brake drum become detached during braking. These brake particles can be released into the environment.

[0004] In conventional drum brakes, at least the braking medium, especially the friction layer of the braking medium, consists of gray cast iron, steel wool, or a coated brake shoe. The wear generated during braking therefore contains metallic brake particles. These can cause damage to the lungs and the human body.

[0005] Drum brakes are known in which magnets are arranged on the brake drum to attract the metallic brake particles and prevent them from getting into the environment.

[0006] An object of an embodiment of the invention is to propose a drum brake for a vehicle in which the number of brake particles released into the environment is further reduced.

[0007] This object is achieved by a drum brake for a vehicle, with at least one brake drum mounted so as to be rotatable about an axis of rotation, with at least one planar armature plate which is non-rotatable with respect to the axis of rotation, wherein the armature plate and the brake drum are spaced apart from one another by a gap without contact and surround a cavity, with at least one brake medium holder arranged in the cavity, which is movably fastened to the armature plate, with at least one brake medium which is fastened to the brake medium holder on the side of the brake medium holder facing the brake drum and which has a friction layer forming a braking surface, which in a braking position contacts the braking surface and generates wear on a contact surface of the brake drum, and with at least one magnetic means by which magnetic or magnetizable brake wear, in particular from the friction layer of the brake medium and / or from the contact surface of the brake drum,is magnetically attractable, wherein at least one of the at least one magnetic means is arranged outside the cavity on the planar armature plate on a side facing away from the brake drum and / or wherein at least one of the at least one magnetic means is arranged within the cavity on the planar armature plate on a side facing the brake drum.

[0008] Because the drum brake comprises a magnetic means, which can be arranged outside the cavity on the flat armature plate on a side facing away from the brake drum, magnetic or magnetizable brake dust emerging from the cavity of the drum brake can be attracted and bound.

[0009] Because at least one of the at least one magnetic means can be arranged on the side of the planar armature plate facing away from the brake drum, clogging and / or blocking of the gap can be prevented and, in particular, the functional operation of the drum brake can be maintained.

[0010] Because the drum brake can comprise a magnetic means arranged within the cavity on the planar armature plate on a side facing the brake drum, magnetic or magnetizable brake wear can be attracted and bound before it can reach the environment via the gap.

[0011] By using both measures alone or in combination with each other, the amount of magnetic or magnetizable brake dust that can reach the environment is reduced.

[0012] The gap can be configured to extend circumferentially around the rotation axis. It can form an air duct from the cavity to the outside, with air from the cavity entering the gap via an inlet and exiting the gap to the environment via an outlet.

[0013] In principle, it is conceivable that at least one of the at least one magnetic means can be arranged at any location outside the cavity on the planar armature plate on the side facing away from the brake drum. In order to be able to attract magnetic or magnetizable brake particles, in particular brake wear, emerging from the gap in an improved manner, it proves advantageous if at least one of the at least one magnetic means, which is arranged outside the cavity on the planar armature plate on the side of the armature plate facing away from the brake drum, is arranged at least in an edge region of the armature plate opposite the gap.

[0014] Furthermore, in one embodiment of the drum brake, it is provided that at least one of the at least one magnetic means, which is arranged within the cavity on the planar armature plate, on the side of the armature plate facing the brake drum, covers the surface of the armature plate facing the brake drum in whole or in sections, wherein an edge region of the surface of the armature plate facing the brake drum, which edge region forms the gap and faces the gap, is designed to be magnet-free.

[0015] If the at least one of the at least one magnetic means within the cavity completely covers the surface of the armature plate facing the brake drum, the number of magnetic or magnetizable brake particles that can be bound by the at least one magnetic means is increased. If the at least one of the at least one braking means is arranged in sections on the surface of the armature plate facing the brake drum, it can, for example, be arranged in an area that has a small distance from the braking surface or contact surface. This can ensure an efficient arrangement and design of the drum brake.

[0016] Because the surface of the armature plate forming the gap and facing the gap is magnet-free, this prevents the gap from clogging from the outside toward the cavity. This also ensures proper operation of the drum brake.

[0017] Binding of magnetic or magnetizable brake dust can be further improved if at least one further one of the at least one magnetic means is arranged outside the cavity and outside the gap adjacent to the gap on the brake drum and / or if at least one further one of the at least one magnetic means is arranged inside the cavity and outside the gap on the brake drum.

[0018] In such a case, in addition to attaching at least one magnetic means to the armature plate, further magnetic means can be arranged in or outside the cavity of the brake drum.

[0019] In a further development of the latter embodiment, it proves to be advantageous if the at least one further magnetic means arranged within the brake drum is arranged on a surface of the brake drum opposite the armature plate and facing the armature plate.

[0020] Furthermore, embodiments of the drum brake are conceivable in which at least one of the at least one magnetic means and / or in which at least one of the at least one further magnetic means is fixed to the brake drum and / or to the armature plate in a detachable manner, in particular in a form-fitting or non-positive manner, in particular by means of screwing, clipping or clamping, or in a non-detachable manner, in particular in a material, form-fitting and / or non-positive manner, in particular by means of gluing, coating, riveting, soldering or welding.

[0021] If the magnetic elements are detachably mounted, they can be easily removed and / or replaced. This can simplify cleaning the magnetic elements.

[0022] If at least one magnetic means is permanently fixed, alternative and appropriate fixing options can be used, if necessary with regard to the necessary installation space and the installation situation.

[0023] The magnetic means can, in principle, comprise any magnetic means. For example, it is conceivable that the magnetic means be an electromagnet or a permanent magnet. If the electromagnet is a permanent magnet, it can be a neodymium magnet, for example.

[0024] It proves to be advantageous if at least one of the at least one magnetic means and / or if at least one of the at least one further magnetic means comprises a magnetic body comprising a three-dimensional shape, a substantially planar magnetic foil, a substantially planar magnetic tape or a magnetic coating, such as magnetic paint.

[0025] In particular, if the magnetic means comprises a flat magnetic tape or a magnetic coating, such as magnetic paint, the magnetic means can be permanently attached, in particular by a material bond, to the brake drum and / or the armature plate. In this case, the magnetic means is compact and space-saving.

[0026] Furthermore, embodiments of the drum brake are conceivable in which at least one of the at least one magnetic means and / or in which at least one of the at least one further magnetic means comprises a circular or annular cross-section and is arranged concentrically with respect to the axis of rotation.

[0027] In such a case, the at least one magnetic means and / or the at least one further magnetic means can completely surround the gap circumferentially with respect to the rotation axis. If the magnetic means comprises a single magnetic means with a circular or annular cross-section and concentric with respect to the rotation axis, the gap can be completely surrounded by a single magnetic means, thereby enabling the drum brake to be designed with a reduced number of components. Furthermore, by surrounding the at least one gap, from the inside or outside, with at least one magnetic means, the magnetic attraction of magnetic or magnetizable brake debris is increased.

[0028] In a further development of the drum brake, it comprises at least two magnetic means which are arranged on the brake drum or on the plate-like brake carrier in a manner uniformly distributed in the circumferential direction with respect to the axis of rotation, in particular in a ring shape.

[0029] The at least two magnetic means can, for example, be designed as ring segments and each extend 180° around the rotational axis. In this case, the drum brake can be completely surrounded by at least two magnetic means. Furthermore, several magnetic means can be provided, which can be arranged as a whole to form a substantially closed ring with respect to the rotational axis.

[0030] Furthermore, embodiments are also conceivable in which two magnetic means are spaced apart from each other without contact.

[0031] If the at least one magnetic means and / or the at least one further magnetic means is arranged only in sections on the brake drum and / or on the planar anchor plate, the attraction and binding of magnetic or magnetizable brake wear can be further increased if the brake drum and / or the planar anchor plate comprises a magnetic or magnetizable material in its entirety or at least in the region of the surface on which the at least one magnetic means is arranged.

[0032] In such a case, the brake drum and / or the planar armature plate is magnetized by arranging the magnetic means itself and thereby binds magnetic or magnetizable material.

[0033] 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 drum brake.

[0034] The drawing shows: Fig. 1 A sectional, schematic side view of a first embodiment of a drum brake; Fig. 2 A sectional, schematic side view of a second embodiment of a drum brake.

[0035] The figures show exemplary embodiments of a drum brake for a vehicle (not explicitly shown in the figures), designated overall by the reference numeral 2. These each comprise a brake drum 6 mounted for rotation about a rotation axis 4. Furthermore, the drum brake 2 comprises a flat anchor plate 8 that is rotationally fixed relative to the rotation axis 4.

[0036] Anchor plate 8 and brake drum 6 are spaced apart from each other by a gap 10 without contact and enclose a cavity 12.

[0037] Furthermore, the drum brake 2 comprises a brake fluid holder 14 arranged in the cavity 12, which is movably secured to the armature plate 8. On the side facing the brake drum 6, the brake fluid holder 14 comprises a brake fluid 16 having a friction layer 20 forming a braking surface 18.

[0038] In a braking position, the braking surface 18 rests against a contact surface 22 of the brake drum 6, causing wear. When the braking medium 16, with the braking surface 18 having the friction layer 20, is applied to the contact surface 22, magnetic or magnetizable brake wear 24 is created.

[0039] In order to attract and bind the magnetic or magnetizable brake dust 24, the embodiments of the drum brake 2 each comprise magnetic means 26, by means of which magnetic or magnetizable brake dust 24 can be magnetically attracted, in particular from the friction layer 20 of the braking means 16 and / or from the contact surface 22 of the brake drum 6.

[0040] Fig. 1 shows a first embodiment of the drum brake 2, in which magnetic means 26 are arranged outside the cavity 12 on the planar armature plate 8 on a side facing away from the brake drum 6. Fig. 1 shows an embodiment in which the magnetic means 26 are arranged at an edge region of the armature plate 8 opposite the gap 10. Furthermore, further magnetic means 26 are arranged on the brake drum 6 outside the cavity 12 and outside the gap 10.

[0041] By the embodiment according to Fig. 1 is magnetic or magnetizable brake dust 24 which passes outwards via the gap 10 and can be attracted and bound by the magnetic means 26 arranged on the outer surfaces of the brake drum 6 and the armature plate 8.

[0042] Fig. Figure 2 shows a second embodiment of the drum brake 2, in which magnetic means 26 are arranged on a side of the planar armature plate 8 facing the brake drum 6 within the cavity 12. The magnetic means 26 are designed such that they at least almost completely cover the surface portion of the planar armature plate 8 facing the cavity 12.

[0043] In addition, the embodiment according to Fig. 2 that additional magnetic means 26 are arranged within the cavity 12 on a side of the brake drum 6 facing the planar armature plate 8. This makes it possible to bind magnetic or magnetizable brake debris 24, which arises within the cavity 12 during braking, already in the cavity 12.

[0044] The Fig. 1 and Fig. 2, it is meant that the magnetic means 26 comprise a magnetic foil and / or a magnetic coating, such as magnetic paint.

[0045] The features of the invention disclosed in the above description, in the claims and in the drawings can be essential both individually and in any combination in the realization of the invention in its various embodiments within the scope of the following claims. List of reference symbols 2 drum brakes 4 axis of rotation 6 brake drum 8 Anchor plate 10 gap 12 Cavity 14 brake fluid holder 16 braking agents 18 braking surface 20 friction layer 22 contact surface 24 Brake wear 26 magnetic media

Claims

[1] Drum brake (2) for a vehicle, with at least one brake drum (6) mounted so as to be rotatable about an axis of rotation (4), with at least one planar anchor plate (8) which is non-rotatable with respect to the axis of rotation (4), wherein the anchor plate (8) and the brake drum (6) are spaced apart from one another by a gap (10) without contact and surround a cavity (12), with at least one brake medium holder (14) arranged in the cavity (12) and which is movably fastened to the anchor plate (8), with at least one brake medium (16) which is fastened to the brake medium holder (14) on the side of the brake medium holder (14) facing the brake drum (6) and which has a friction layer (20) forming a braking surface (18) which, in a braking position, bears against a contact surface (22) of the brake drum (6) in contact with the braking surface (18) and producing wear, and with at least one magnetic means (26) through which magnetic or magnetizable brake wear (24),in particular by the friction layer (20) of the braking means (16) and / or by the contact surface (22) of the brake drum (6), wherein at least one of the at least one magnetic means (26) is arranged outside the cavity (12) on the planar anchor plate (8) on a side facing away from the brake drum (6) and / or wherein at least one of the at least one magnetic means (26) is arranged within the cavity (12) on the planar anchor plate (8) on a side facing the brake drum (6). [2] Drum brake (2) according to claim 1, characterized by that at least one of the at least one magnetic means (26) which is arranged outside the cavity (12) on the planar armature plate (8), on the side of the armature plate (8) facing away from the brake drum (6), is arranged at least in an edge region of the armature plate (8) opposite the gap (10). [3] Drum brake (2) according to claim 1 or 2, characterized bythat at least one of the at least one magnetic means (26) which is arranged within the cavity (12) on the planar armature plate (8), on the side of the armature plate (8) facing the brake drum (6), covers the surface of the armature plate (8) facing the brake drum (6) entirely or in sections, wherein an edge region of the surface of the armature plate (8) facing the brake drum (6), which edge region forms the gap (10) and faces the gap (10), is designed to be magnet-free. [4] Drum brake (2) according to one of the preceding claims, characterized by that at least one further one of the at least one magnetic means (26) is arranged outside the cavity (12) and outside the gap (10) adjacent to the gap (10) on the brake drum (6) and / or that at least one further one of the at least one magnetic means (26) is arranged inside the cavity (12) and outside the gap (10) on the brake drum (6). [5] Drum brake (2) according to claim 4, characterized by that the at least one further magnetic means (26) arranged within the brake drum (6) is arranged on a surface of the brake drum (6) opposite the armature plate (8) and facing the armature plate (8). [6] Drum brake (2) according to one of the preceding claims, characterized by that at least one of the at least one magnetic means (26) and / or that at least one of the at least one further magnetic means (26) is fixed to the brake drum (6) and / or to the armature plate (8) in a detachable manner, in particular in a form-fitting or force-fitting manner, in particular by means of screwing, clipping or clamping, or in a non-detachable manner, in particular in a material, form-fitting and / or force-fitting manner, in particular by means of gluing, coating, riveting, soldering or welding. [7] Drum brake (2) according to one of the preceding claims, characterized bythat at least one of the at least one magnetic means (26) and / or that at least one of the at least one further magnetic means (26) comprises a magnetic body comprising a three-dimensional shape, a substantially planar magnetic foil, a substantially planar magnetic tape or a magnetic coating, such as magnetic paint. [8] Drum brake (2) according to one of the preceding claims, characterized by that at least one of the at least one magnetic means (26) and / or that at least one of the at least one further magnetic means (26) comprises a circular or annular cross-section and is arranged concentrically with respect to the axis of rotation (4). [9] Drum brake (2) according to one of the preceding claims, characterized byat least two magnetic means (26) which are arranged on the brake drum (6) or on the plate-like brake carrier in a manner uniformly distributed in the circumferential direction with respect to the axis of rotation (4), in particular in a ring shape. [10] Drum brake (2) according to one of the preceding claims, characterized by that the brake drum (6) and / or the planar anchor plate (8) comprises a magnetic or magnetizable material entirely or at least in the region of the surface on which the at least one magnetic means (26) is arranged.

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