BRUSH FOR CLEANING VEHICLE WHEELS

Description

[0001] The present invention relates to a brush for cleaning vehicle wheels. The brush comprises a main brush which is rotatable about a central axis and has a radius and a recess. The brush further comprises a secondary brush which is rotatable about a longitudinal axis and has an effective radius, wherein the longitudinal axis of the secondary brush is arranged at a distance from the central axis, the effective radius is smaller than the radius of the main brush, the secondary brush is arranged in the recess of the main brush, and the secondary brush rotates with the recess when the main brush rotates about the central axis. Furthermore, the brush comprises cleaning elements which are arranged on the front sides of the main brush and the secondary brush. The invention further relates to a device having such a brush.

[0002] Conventional wheel cleaning brushes have the problem that, due to a rotational movement perpendicular to the spokes of a wheel rim, the treatment bristles, which are immersed in the space between the spokes during the washing movement, are deflected backward in the direction of movement due to the transverse movement and the support on the next spoke edge. These bristles have no active cleaning effect. This effect is further amplified by the fact that the bristles support each other, and the bristles that are already deflected backward prevent the subsequent bristles from engaging.

[0003] EP 2 287 053 B1 discloses a device for cleaning vehicle wheels. The device comprises a rotating body with cleaning elements that can be rotated about a central axis and driven by a drive motor. The rotating body also has turntables that are rotated not only about the central axis but also about their own longitudinal axis via a gear mechanism.

[0004] A similar device is described in EP 3 246 217 A1. It has an annular main brush that rotates around a central axis. Furthermore, a central brush rotates around the central axis. Furthermore, intermediate brushes are arranged within the annular main brush. When the brushes come into contact with a wheel to be cleaned during operation, the intermediate brushes rotate both around the central axis and around their own axis.

[0005] Also known from EP 1 561 658 A2 is a washing device for vehicle tires in which a brush arranged outside a main axis is mounted so as to be rotatable both about its own axis and about the main axis.

[0006] GB 2 082 991 A describes a device for washing vehicle wheels with a disc-shaped washing brush arranged eccentrically on a rotatable disc. Finally, EP 3 266 342 A1 discloses a brush whose bristles are attached to a base plate in such a way that they are inclined in both the radial and non-radial directions.

[0007] Another wheel washing device is known from DE 20 2011 110 362 U1.

[0008] It is the object of the present invention to provide a brush of the type mentioned above, by means of which the washing result in an automatic cleaning of vehicle rims can be improved.

[0009] This object is achieved according to the invention by a brush having the features of claim 1. Advantageous embodiments and further developments emerge from the dependent claims. The brush according to the invention is characterized in that the distance between the central axis and the longitudinal axis is less than or equal to the effective radius of the secondary brush. The distance between the central axis and the longitudinal axis is in particular less than the effective radius of the secondary brush. According to the invention, the effective radius of the secondary brush is understood to be the radius of the area that the secondary brush sweeps over when rotating only about its own longitudinal axis. If the longitudinal axis of the secondary brush is not arranged centrally in the secondary brush, the effective radius is larger for the same size of the secondary brush than for a centrally arranged longitudinal axis. The effective radius can also be determined by the position at which the cleaning element is attached.The closer a cleaning element is attached to the edge of the secondary brush, the larger the effective radius of the secondary brush.

[0010] The brush according to the invention can be used in particular for cleaning vehicle rims whose diameter is so small that the secondary brush extends beyond the outer circumference. A vehicle rim generally comprises spokes that converge in the center of the rim to form a wheel hub, and a rim well that is arranged at the outer circumference of the vehicle rim. Due to the special geometry of the brush according to the invention, the effective radius of the secondary brush extends at least to the center of the vehicle rim when the brush is arranged accordingly relative to the vehicle rim. A projection of a movement of a cleaning element of the secondary brush onto the vehicle rim then results in a longitudinal movement along the spokes, preferably also sweeping over the wheel hub. The cleaning elements strike the spokes at least at an acute angle, i.e. the tangent of their trajectory encloses an acute angle with the surface of the spoke.In the area of ​​the rim base, however, the secondary brush performs a wiping motion outwards and back again. The special geometry of the brush according to the invention advantageously prevents the cleaning elements of the brush from bending at the spoke edges during cleaning, thereby rendering them inactive for the washing process. Furthermore, by combining the secondary brush with the main brush, the washing motion of the secondary brush can be combined with a conventional washing motion of the main brush to achieve improved washing results.

[0011] In the known multi-part cleaning brushes with superimposed rotational movements, the geometry prevents effective longitudinal movement along the rims from the rim well to the wheel hub. By rotating the secondary brushes, which does not generate any longitudinal movement along the entire rim, the negative support effects and the associated reduction in washing performance are only canceled out in limited areas. In one embodiment, the sum of the distance of the central axis to the longitudinal axis and the effective radius of the secondary brush is greater than x times the radius of the main brush, where the factor x is greater than or equal to 0.8, in particular greater than or equal to 0.9 and preferably greater than or equal to 1. However, to ensure that the cleaning elements of the secondary brush do not extend too far beyond the rim well to be cleaned, the factor x should be less than 1.2, in particular less than 1.1.This advantageously ensures that the effective radius of the secondary brush, with appropriate positioning of the brush relative to the vehicle rim, extends beyond the center of the vehicle rim and at least close to the rim well. If the factor x is 1, the active washing area of ​​the secondary brush is at least equal to that of the main brush. During operation, the effective radius of the secondary brush then extends to the rim well or beyond. The factor x can be selected depending on the size of the rim to be cleaned. For a larger rim, the factor x is larger than for a smaller rim. For a smaller rim, for example, it may be sufficient for the outermost cleaning elements of the secondary brush to only reach up to 80% of the outer edge of the rim to be cleaned.With a larger rim, however, it is preferable that the outermost cleaning elements of the secondary brush reach to the outer edge of the rim.

[0012] The device according to the invention enables the superposition of three directions of movement of cleaning elements. Firstly, the cleaning elements of the main brush perform a concentric rotational movement to the rim around the central axis. Secondly, the cleaning elements of the secondary brush perform a wiping movement outwards and back again in the area of ​​the rim base, as well as a movement along the spokes of the rim up to the wheel hub. This ensures that the cleaning elements sweep over the rim at an angle that actively washes the rim in all areas of the rim. This increases the cleaning performance. This also advantageously prevents the cleaning elements of the brush from bending at the spoke edges during cleaning, or from being rejected or deflected, thus becoming inactive for the washing process.

[0013] In a further embodiment, the distance between the central axis and the longitudinal axis is less than half the radius of the main brush. This advantageously ensures that the secondary brush is arranged closer to the central axis than to the circumference of the main brush, thus ensuring effective cleaning of the hub of a vehicle rim. If, at the same time, the secondary brush reaches to the outer edge in order to also clean the rim base of a vehicle rim, i.e., if the radius of the main brush is less than the sum of the distance between the central axis and the longitudinal axis and the effective radius of the secondary brush, the secondary brush does not protrude too far beyond the radius of the main brush in this embodiment.

[0014] In a further embodiment, the distance between the central axis and the longitudinal axis is greater than y times the radius of the main brush, where y is greater than or equal to 0.2, in particular greater than or equal to 0.3. This advantageously ensures that the secondary brush is not arranged too close to the central axis, thus ensuring that the cleaning elements of the secondary brush perform a cleaning movement along the spokes of the rim, i.e., an acute angle is formed between the cleaning movement of the cleaning elements of the secondary brush and the longitudinal extension of the spokes.

[0015] In one embodiment, the main brush has a circular circumference or, if the recess is taken into account, a circular circumferential section with the radius of the main brush, with the central axis being arranged within the circular circumference of the main brush. The main brush can be designed, in particular, as a circular disk or annular disk. However, the shape of the main brush is reduced by the recess, so that the main brush forms only part of a circular disk or annular disk. This allows the brush to be adapted, in particular, to the geometry of a vehicle rim to be cleaned.

[0016] The central axis of the main brush and the longitudinal axis of the secondary brush are aligned essentially parallel to each other, preferably parallel to each other. This ensures that the main and secondary brushes are aligned parallel to the rim during cleaning.

[0017] The main brush has, in particular, a sickle shape, wherein the sickle shape is formed by a difference in area between an overlapped disc and an overlapping disc, and wherein the recess comprises at least a partial area of ​​the overlapping disc. Both discs are circular discs. To form the sickle shape, the radius of the overlapping disc can generally be larger, the same size, or smaller than the radius of the overlapped disc. However, in order to ensure the inventive size of the distance between the central axis and the longitudinal axis of the secondary brush, the radius of the overlapping disc is, in particular, smaller than the radius of the overlapped disc, but the overlapping disc covers the center point and a circumferential section of the overlapped disc.

[0018] Furthermore, the auxiliary brush can have a circular circumference with a radius, wherein the longitudinal axis of the auxiliary brush is arranged within the circular circumference of the auxiliary brush. In particular, the longitudinal axis of the auxiliary brush is arranged in the center of the circular circumference of the auxiliary brush. The auxiliary brush then rotates about its central axis. The auxiliary brush can also be a circular disk or a circular disk ring. The radius of the auxiliary brush can then be adapted to the radius of the recess. However, a free space of a few millimeters is left between the main brush and the auxiliary brush in order to avoid friction between the two bodies of the main brush and the auxiliary brush. In the area of ​​the recess, the auxiliary brush protrudes beyond the circumference of the main brush.

[0019] In particular, the radius of the secondary brush can be substantially equal to the effective radius. For this purpose, the cleaning elements of the secondary brush are arranged, in particular, close to the edge of the secondary brush's circular disc. "Close to the edge" here means that an area of ​​up to 3 cm can remain free between the positions where the cleaning elements are mounted and the edge of the secondary brush's circular disc. If the cleaning elements extend perpendicularly from the surface of the secondary brush, the radius of the circular disc is slightly larger than the effective radius of the secondary brush. Furthermore, the cleaning elements can also extend slightly diagonally from the surface of the circular disc toward the vehicle rim to be cleaned. The angle that the outermost cleaning element forms with the surface can be selected such that the radius of the circular disc actually matches the effective radius of the secondary brush.

[0020] By simultaneously rotating the secondary brush around both its central axis and its own longitudinal axis during cleaning, a cleaning element describes a hypocycloid pattern over the area to be cleaned. This movement can effectively improve coverage of the area to be cleaned. In particular, the hypocycloid can be a hypotrochoid. By adjusting the speed of rotation around the central axis to the speed of rotation around the longitudinal axis, the number of inflection points of the hypocycloid or hypotrochoid can be adjusted.

[0021] The direction of rotation of the main brush and the direction of rotation of the secondary brush are, in particular, opposite to each other. The rotational movement of the secondary brush is advantageously derived from the rotational movement of the main brush. For this purpose, a fixed external gear can mesh with a gear that is firmly connected to the longitudinal axis of the secondary brush. In particular, a planetary gear is used to transmit the rotation of the main brush to the secondary brush. This allows the two brush parts to rotate in opposite directions. Alternatively, the desired directions of rotation can also be generated using gears without external gears, chain drives, or belt drives.

[0022] In one embodiment, the cleaning elements of at least the secondary brush have bristles which are combined to form tufts of bristles, wherein at least the bristles of the tufts of bristles are arranged obliquely to one another in such a way that they form an X-shape.

[0023] Furthermore, at least the secondary brush can be divided into segments, with the bristle tufts forming an X-shape being arranged in a first segment, and the bristle tufts being arranged in a second segment such that they are aligned substantially perpendicular to the surface of the secondary brush. In particular, the X-shaped bristle tufts of the first segment are longer than the bristle tufts of the second segment. This allows the X-shaped bristle tufts to penetrate into cavities or gaps in the rim, while the straight-set bristle tufts can clean the front sides of the spokes.

[0024] In addition, the bristle tufts of the first segment are shaped in such a way that the X-shape is tapered to a roof. This ensures that, during operation, the brush always provides bristles facing the rim side and with varying penetration depths between the spokes. This also allows the inside of the rim to be effectively cleaned.

[0025] The invention further relates to a cleaning device for cleaning vehicle wheels, comprising such a brush and a transmission means by which the rotation of the main brush can be transmitted to the secondary brush. Such transmission means form, for example, a planetary gear. The cleaning device is arranged, in particular, in a conventional vehicle washing system.

[0026] The invention will now be explained using embodiments with reference to the accompanying drawings. Figure 1 shows an embodiment of an arrangement of an embodiment of the brush according to the invention relative to a vehicle wheel, Figure 2a shows an embodiment of a geometry of a main brush, Figure 2b shows an embodiment of the brush according to the invention, Figure 3a shows an embodiment of the arrangement of bristle tufts, Figure 3b shows an embodiment of the bristle arrangement of the secondary brush, Figure 4 shows a projection of a movement of a bristle tuft of the secondary brush onto a vehicle rim in the region of the spokes, Figure 5 shows a projection of a movement of a bristle tuft of the secondary brush onto a vehicle rim in the region of the rim base, Figure 6 shows a trajectory that describes a bristle tuft of the secondary brush during operation of the brush on the vehicle rim, and Figure 7 shows a projection of a movement of a bristle tuft of the main brush onto a vehicle rim.

[0027] With reference to the Figures 1, 2a and 2bA first embodiment of a brush 1 according to the invention is explained. In Figure 1 A cross-section through the brush 1 is shown from a side view. Figures 2a and 2b Parts of the brush 1 are shown from a front view. Such a brush 1 is part of a cleaning device, which in turn is arranged in a car wash for cleaning vehicles.

[0028] Furthermore, Figure 1 a vehicle wheel 3 to be cleaned is shown. The vehicle wheel 3 has a vehicle rim 4. The structure of a vehicle rim 4 is shown as an example in the Figures 4, 5 and 7shown. The vehicle rim 4 has spokes 6.1 and a space 6.2 between each two adjacent spokes 6.1. Furthermore, the rim 4 has a region 6.3 in the center where the spokes 6.1 converge. This region is referred to as the wheel hub 6.3. Furthermore, the vehicle rim 4 has a rim base 6.4 running around its circumference.

[0029] Brush 1 comprises a main brush 2.1 and a secondary brush 2.2. Both the main brush 2.1 and the secondary brush 2.2 have a circular circumference. However, the circular circumference of the main brush 2.1 is interrupted by a recess 2.1', as explained later.

[0030] The brush 1 further has a central axis A1. The central axis A1 is the center axis of the main brush 2.1. During a cleaning process of a vehicle wheel 3, the brush 1 is positioned relative to the vehicle wheel 3 such that the central axis A1 of the brush 1 and the center axis A2 of the vehicle wheel 3 coincide. The central axis A1 is positioned within the circular circumference of the main brush 2.1.

[0031] The main brush 2.1 and the secondary brush 2.2 also have cleaning elements 5. The cleaning elements 5 of the main brush 2.1 are aligned perpendicular to the surface of the main brush 2.1. The secondary brush 2.2 has cleaning elements 5 that extend close to the edge of the circular circumference of the secondary brush 2.2. The cleaning elements 5 are, in particular, bristles grouped together in tufts. The secondary brush 2.2 can also have tufts of bristles toward its center.

[0032] In Figure 2a the main brush 2.1 is shown. The main brush 2.1 rotates during cleaning operation around the central axis A1 of the brush 1. The main brush 2.2 has a crescent shape. The crescent shape is formed by a differential area between a disk K1, which is overlapped by a second disk K2. The radius R1 of the overlapped disk K1 is greater than the radius of the overlapping disk K2. The radius R1 of the overlapped disk K1 corresponds in particular to the radius of the main brush 2.1. The area of ​​the overlapping disk K2 forms the area of ​​a recess 2.1' in the main brush 2.1. When the brush 1 rotates around the central axis A1, the secondary brush 2.2 rotates in the recess 2.1', around the central axis A1. In addition, the secondary brush 2.2 rotates during operation around its longitudinal axis A3, which is arranged in the center of the circular circumference of the secondary brush 2.2.

[0033] In Figure 2bthe entire brush 1 is shown, which comprises the main brush 2.1 and the auxiliary brush 2.2. The auxiliary brush 2.2 is arranged in the recess 2.1'. The auxiliary brush 2.2 is also designed as a rotating disk, the shape of which is essentially adapted to that of the recess 2.1' of the main brush 2.1. The form fit of the auxiliary brush 2.2 results in the overall basic geometric shape of a circular disk for the brush 1. The central axis A1 and the longitudinal axis A3 are arranged at a distance E from one another. The distance E is smaller than the effective radius R2 of the auxiliary brush 2.2, within which the auxiliary brush 2.2 exerts a cleaning effect on the vehicle rim 4.

[0034] The diameter D of the secondary brush 2.2 is selected such that, when the brush 1 is arranged relative to the vehicle wheel 3, the cleaning elements 5, which are arranged near the edge of the circular disk of the secondary brush 2.2, extend beyond the central axis A2 of the vehicle rim 4 and beyond the rim well 6.4, i.e. beyond the rim edge A4 of the vehicle rim 4. The effective radius R2 therefore extends on one side beyond the central axis A2 of the vehicle rim 4 to be treated and on the other side beyond the rim well 6.4 of the vehicle rim 4. The radius R1 of the main brush 2.1, which is adapted to the radius of the rim well 6.4, is therefore smaller than the sum of the distance E of the central axis A1 to the longitudinal axis A3 and the effective radius R2 of the secondary brush 2.2. The radius R1 of the main brush 2.1 can be adapted to the radius of the outer edge of the rim base 6.4 in such a way that this radius corresponds to the radius R1 of the main brush 2.1.

[0035] In other embodiments, the effective radius R2 extends on one side beyond the center axis A2 of the vehicle rim 4 to be treated and on the other side up to at least 80% or 90% of the radius R1 of the main brush 2.1. This radius R1 of the main brush 2.1 can correspond to the radius of the outer edge of the rim well 6.4.

[0036] In the embodiment described here or in other embodiments, the distance E is less than half the radius R1 of the main brush 2.1. Furthermore, in the embodiment described here or in other embodiments, the distance E is greater than 0.2 or 0.3 times the radius R1 of the main brush 2.1.

[0037] In the embodiments shown here or in other embodiments, the following relationships may apply: E < R 2 E + R 2 > x ⋅ R 1 , where x ≥ 0.8, in particular x ≥ 0.9 or x ≥ 1, E < 0 , 5 ⋅ R 1 E > y ⋅ R 1 , where y ≥ 0.2, in particular y ≥ 0.3.

[0038] The longitudinal axis A3 of the secondary brush 2.2 is also located in the center of the circular disk of the secondary brush 2.2. Furthermore, the cleaning elements 5 are arranged near the edge of the circular disk of the secondary brush 2.2. This ensures that the effective radius R2 of the secondary brush 2.2 is essentially equal to the radius of the secondary brush 2.2.

[0039] The rotation of the secondary brush 2.2 in brush 1 is derived from the rotation of the main brush 2.1. For this purpose, the cleaning device has, for example, a planetary gear in which a fixed external gear meshes with a planetary gear that is firmly connected to the axis A3 of the secondary brush 2.2 and is guided in a circle around the central axis A1 by means of a web. When the main brush 2.1 rotates in the direction of rotation DR1, the secondary brush 2.2 is rotated in the direction of rotation DR2 about its own axis A3 and simultaneously about the central axis A1. The direction of rotation DR1 is oriented opposite to the direction of rotation DR2. When the main brush 2.1 rotates, the secondary brush 2.2 rotates simultaneously with the recess 2.1' about the central axis A1 and about its own longitudinal axis A3.

[0040] Alternatively, the desired rotation directions DR1 and DR2 can also be generated by gears without external gears, chain drives or belt drives.

[0041] With reference to the Figures 3a and 3b the bristles of the secondary brush 2.2 are explained.

[0042] The secondary brush 2.2 is divided into first segments 7.2 and second segments 7.1. In the first segments 7.2, the bristles of the cleaning elements 5 are aligned diagonally to one another, forming an X-shape. This results in the bristle tufts 5.2. In the second segments 7.1, the bristles of the cleaning elements 5 are arranged in the conventional manner. This means that the bristles grouped into tufts 5.1 are arranged such that they form a 90° angle or an angle slightly slanted outwards with the surface of the secondary brush 2.2 in the second segment 7.1. This results in the bristle tufts 5.1. Furthermore, the X-shaped bristle tufts 5.2 are longer than the bristle tufts 5.1. In addition, the bristles of the bristle tufts 5.2 are designed such that the X-shape also results in a roof shape. Due to the special design of the X-shaped bristle tufts 5.2 ensures that bristles with different immersion depths are always present, directed toward the rim. Immersion depth refers to the depth to which the bristle tufts 5.2 can penetrate the space 6.2 located between the spokes 6.1 of the vehicle rim 4.

[0043] With reference to the Figures 4, 5 and 6 Projections of the movement of a bristle tuft 5 of the secondary brush 2.2 in the area of ​​the vehicle rim 4 are described.

[0044] By superimposing the rotation of the secondary brush around its own axis A3 and around the central axis A1, a tuft of bristles 5.1 and 5.2 results in Figure 6 shown motion trajectory B3. The motion trajectory B3 represents a hypocycloid. The turning points of the hypocycloid B3 can be adjusted via the ratio of the rotation frequencies around the central axis A1 and around the axis A3 of the secondary brush 2.2.

[0045] The cycloid movement B3 describes a relative movement along the spokes 6.1 in the area of ​​the spokes 6.1, as in Figure 4 shown. Furthermore, a tuft of bristles 5.1 or 5.2 sweeps over the wheel hub 6.3 during the cycloidal motion B3. This movement along the spokes 6.1 eliminates the problem of bristles of the cleaning elements 5 bending at the spoke edge. Therefore, the number of bristles effectively involved in the cleaning process can be increased.

[0046] The hypocycloid B3 is, in particular, a hypotrochoid. A hypotrochoid is a special form of a hypocycloid. A hypotrochoid is generated by rolling a circle within a fixed circle. Each of the bristle tufts 5.1 and 5.2 describes a hypotrochoid B3. In the present embodiment, the points generating the hypotrochoid B3 lie within or on the effective radius R2 of the secondary brush 2.2.

[0047] In addition, the diameter D of the secondary brush 2.2 allows the bristle tufts 5.1 and 5.2 to extend beyond the rim base 6.4 of the vehicle rim 4. In the area of ​​the rim base 6.4, a wiping movement B2 is created outwards and back again (see Figure 5 ). Therefore, the rim base 6.4 is also effectively cleaned.

[0048] With reference to Figure 7 The projection of the movement of a tuft of bristles of the cleaning elements 5 of the main brush 2.1 onto the vehicle rim 4 is described. A tuft of bristles of the main brush 2.1 executes a concentric rotational movement B4 toward the vehicle rim 4 and thereby cleans the vehicle rim 4 in a conventional manner.

[0049] By combining movements B1, B2 and B4, an improved cleaning result is achieved for the vehicle rim 4. List of reference symbols

[0050] 1Brush 2.1Main brush 2.1Recess 2.2Secondary brush 3Vehicle wheel 4Vehicle rim 5Cleaning elements 5.1Bristle tufts 5.2X-shaped bristle tufts 6.1Spokes 6.2Spaces between spokes 6.3Wheel hub 6.4Rim well 7.1, 7.2Second segment; first segment A1Central axis A2Central axis of the vehicle wheel A3Longitudinal axis A4Rim edge B1Longitudinal movement B2Wiping movement B3Hypotrochoid B4Movement of a bristle tuft of the main brush DDiameter DR1; DR2Directions of rotation EWay between central axis and longitudinal axis K1Overlapped disc K2Overlapping disc R1; R2Radius

Claims

1. Brush (1) for cleaning vehicle wheels (3), comprising a main brush (2.1) rotatable about a central axis (A1), which has a radius (R1) and a recess (2.1'), an auxiliary brush (2.2) rotatable about a longitudinal axis (A3), which has an effective radius (R2), wherein the longitudinal axis (A3) of the auxiliary brush (2.2) is arranged at a distance (E) from the central axis (A1), the effective radius (R2) is smaller than the radius (R1) of the main brush (2.1), the auxiliary brush (2.2) is arranged in the recess (2.1') of the main brush (2.1) and the auxiliary brush (2.2.) rotates with the recess (2.1') when the main brush rotates about the central axis (A1), and cleaning elements (5), which are arranged on the end face on the main brush (2.1) and the auxiliary brush (2.2), characterised in that the distance (E) between the central axis (A1) and the longitudinal axis (A3) is less than or equal to the effective radius (R2) of the auxiliary brush (2.2).

2. Brush (1) according to claim 1, characterised in that the total of the distance (E) between the central axis (A1) and the longitudinal axis (A3) and of the effective radius (R2) of the auxiliary brush (2.2) is greater than x times the radius (R1) of the main brush (2.1), wherein the factor x is greater than or equal to 0.8, in particular is greater than or equal to 0.9 and preferably is greater than or equal to 1.

3. Brush (1) according to claim 1 or 2, characterised in that the distance (E) between the central axis (A1) and the longitudinal axis (A3) is less than half the radius (R1) of the main brush (2.1).

4. Brush (1) according to one of the preceding claims, characterised in that the distance (E) between the central axis (A1) and the longitudinal axis (A3) is greater than y times the radius (R1) of the main brush (2.1), wherein y is greater than or equal to 0.2, in particular is greater than or equal to 0.3.

5. Brush (1) according to one of the preceding claims, characterised in that the main brush (2.1) has a circular circumference with the radius (R1), wherein the central axis (A1) is arranged inside the circular circumference of the main brush (2.1).

6. Brush (1) according to one of the preceding claims, characterised in that the main brush (2.1) has a crescent shape, wherein the crescent shape is formed by a differentiated area between an overlapped disc (K1) and an overlapping disc (K2) and wherein the recess (2.1') has at least one partial surface of the overlapping disc (K2).

7. Brush (1) according to one of the preceding claims, characterised in that the auxiliary brush (2.2) has a circular circumference with a radius (R3), wherein the longitudinal axis (A3) is arranged inside the circumference of the auxiliary brush (2.2).

8. Brush (1) according to one of the preceding claims, characterised in that the longitudinal axis (A3) of the auxiliary brush (2.2) is arranged in the centre of the circular circumference of the auxiliary brush (2.2).

9. Brush (1) according to one of the preceding claims, characterised in that the radius of the auxiliary brush (2.2) is substantially identical to the effective radius (R2).

10. Brush (1) according to one of the preceding claims, characterised in that the rotational direction (DR1) of the main brush (2.1) and the rotational direction (DR2) of the auxiliary brush (2.2) are opposed to each other.

11. Brush (1) according to one of the preceding claims, characterised in that the cleaning element (5) at least of the auxiliary brush (2.2) has bristles, which are combined to form tufts of bristles (5.2), wherein at least the bristles of the tufts of bristles (5.2) are arranged diagonally to each other in such a way that they form an X shape.

12. Brush (1) according to claim 11, characterised in that at least the auxiliary brush (2.2) is divided into segments (7.1, 7.2), wherein the tufts of bristles (5.2), which form an X shape, are arranged in a first segment (7.2), and the tufts of bristles (5.1) are arranged in a second segment (7.1) in such a way that they are oriented substantially perpendicular to the surface of the auxiliary brush (2.2).

13. Brush (1) according to claim 12, characterised in that the tufts of bristles (5.2) of the first segment (7.2) are longer than the tufts of bristles (5.1) of the second segment (7.1).

14. Brush (1) according to one of claims 12 or 13, characterised in that the tufts of bristles (5.2) of the first segment (7.2) are shaped in such a way that the X shape comes to a point like a roof.

15. Cleaning device for cleaning vehicle wheels (3) with a brush (1) according to one of claims 1 to 14 and transmission means, by means of which a rotation of the main brush (2.1) can be transmitted to the auxiliary brush (2.2).