CN111867688B

CN111867688B - Brake system, axle carrier unit for a low-floor vehicle, low-floor vehicle with such an axle carrier unit, and drive unit

Info

Publication number: CN111867688B
Application number: CN201980019932.1A
Authority: CN
Inventors: M·P·迈尔; J·D·H·奥尔瑟
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Technologies AG and Co KG
Priority date: 2018-03-29
Filing date: 2019-03-26
Publication date: 2022-06-17
Anticipated expiration: 2039-03-26
Also published as: DE112019001641A5; CN111867688A; DE102018126959A1; DE102018126957A1; WO2019185092A1

Abstract

The invention relates to a brake system (30) having a rotor (5) which can be rotated about a rotational axis (D) and having a brake device (10) for braking the rotor (5), wherein the brake device (10) has a first brake element (13) which can be moved between a rest position, in which an annular brake surface (14) of the first brake element (13) is arranged concentrically to the rotational axis (D) of the rotor (5) and remote from the rotor (5), and a braking position, in which a brake surface (14) of the first brake element (13) is in contact with the rotor (5) or with a second brake element (9) which is connected in a rotationally fixed manner to the rotor (5), wherein the first brake element (13) can be moved hydraulically between the rest position and the braking position, wherein the first brake element (13) is connected to a hollow-cylindrical brake piston (12) which is mounted in a housing (11) having a hollow-cylindrical interior (11.1) for receiving hydraulic fluid, wherein the first brake element (13) is designed in the form of a ring and has, on its inner contour, a first-type counter-element (24), in particular a plurality of teeth or wedges, which co-operate with a corresponding second-type counter-element (23) on the outer contour of the housing (11) in such a way that: the first braking element (13) is locked for rotation about the axis of rotation (D) but is movable parallel to the axis of rotation (D). The invention further relates to an axle bearing unit (4) for a low-floor vehicle, in particular for a scooter, with a brake system (30) according to one of the preceding claims, wherein the rotating element (5) of the brake system is designed as a wheel, and to a low-floor vehicle (1) with such an axle bearing unit (4). The invention further relates to a drive unit having such a brake system (30).

Description

Brake system, axle carrier unit for a low-floor vehicle, low-floor vehicle with such an axle carrier unit, and drive unit

Technical Field

The invention relates to a brake system having a rotor rotatable about an axis of rotation and having a brake device for braking the rotor, wherein the brake device has a first brake element which can be moved between a rest position, in which an annular braking surface of the first brake element is arranged concentrically to the rotor axis of rotation and remote from the rotor, and a braking position, in which the braking surface of the first brake element is in contact with the rotor or with a second brake element connected to the rotor in a rotationally fixed manner. The invention further relates to an axle carrier unit for a low-floor vehicle, in particular a scooter, having at least one wheel which can be rotated about an axis of rotation and a braking device for braking the wheel, wherein the braking device has a first braking element which can be moved between a rest position, in which an annular braking surface of the first braking element is arranged concentrically to the axis of rotation of the wheel and remote from the wheel, and a braking position, in which the braking surface of the first braking element is in contact with the wheel or with a second braking element which is connected to the wheel in a rotationally fixed manner. The invention further relates to a low-floor vehicle with such an axle bearing unit. The invention also relates to a drive unit with the aforementioned brake system, wherein the rotating element of the brake system is designed as a drive element, in particular as a drive wheel or drive pinion.

Background

A low-floor vehicle designed as a scooter is known, for example, from US 6659480B 1. This scooter has a shaft support unit with two wheels as a rear shaft, on which a brake device for braking the wheels is arranged. Each wheel is assigned a brake element which has an annular brake surface and which, in the rest position of the brake element, is arranged remote from the respective wheel. The pivotable lever can move the brake element into a braking position in which it abuts against a further brake element connected to the respective wheel in a rotationally fixed manner.

In this scooter, it has proven to be disadvantageous that the pivotable lever exerts a force on the first brake element primarily in the region above the wheel rotation axis. During braking, the forces acting on the wheel can therefore subject the wheel bearing to an asymmetrical load and can lead to premature failure of the wheel bearing. Thereby affecting the service life of the vehicle.

US 4295547 a describes a scooter with a brake device, wherein a brake element can be moved hydraulically between its rest position and its braking position, in which it is in contact with the front side of the wheels of the scooter. That is, the pressure required for braking can be more uniformly distributed in the braking device. However, it has proven to be disadvantageous that a relatively high torque acts on the brake element during braking. There is therefore a risk of the braking element accidentally twisting. Rotation of the brake element may adversely affect the sealing of the brake hydraulic system.

Disclosure of Invention

In this context, the following tasks are proposed, namely: provided is a brake device which is suitable for a low-floor vehicle and can prolong the service life of the vehicle.

The object is achieved by a brake system according to claim 1 and a shaft support unit according to claim 8.

The invention provides that the first brake element can be hydraulically moved between a rest position and a braking position.

According to the invention, a hydraulic force is applied to the first brake element in order to move it between the rest position and the braking position, whereby the pressure required for braking can be distributed more evenly. This also distributes the forces introduced into the wheel or into the second brake element arranged on the wheel more uniformly. In this way, the risk of overloading individual regions of the wheel or of the wheel bearing arrangement can be reduced. This reduces the probability of premature failure of the wheel bearing and prolongs the service life of the vehicle.

Preferably, the first braking element can be moved hydraulically from the rest position into the braking position and from the braking position into the rest position. Alternatively, it can be provided that the first brake element can be moved hydraulically from the rest position into the braking position and that the braking device has a restoring element which can move the first brake element from the braking position back into the rest position. The return element can be designed, for example, as a spring element.

The invention provides that the first brake element is connected to a hollow-cylindrical brake piston which is mounted in a housing having a hollow-cylindrical interior for receiving hydraulic fluid. An advantage of such a design is that less installation space is required compared to a brake device having a lever or lever mechanism for actuating the first brake element. The housing may be arranged concentrically with the wheel rotation axis and/or with one of the shaft sections of the shaft support unit. Alternatively, the first brake element can also be designed in one piece with the brake piston.

The invention provides that the first brake element is designed as a ring and has, on the inner contour, a first-type counter-element, in particular a plurality of teeth or wedges, which interact with a corresponding second-type counter-element on the outer contour of the housing in such a way that: the first brake element is locked for rotation about the axis of rotation but is movable parallel to the axis of rotation. This allows a simple design to achieve a rotational locking of the first brake element relative to the housing, while ensuring its axial displaceability. The outer contour of the housing can be designed in the form of a spline shaft or a feather key in a region which interacts with the first braking element.

In this case, it is advantageous if the housing is clamped to a shaft section or shaft bearing unit of the brake system, so that no connecting elements are required for connecting the housing to the shaft section. The number of parts required for assembly can thereby be reduced, which in turn also reduces the material costs. Alternatively or additionally, the housing is preferably clamped to a stator section of an electric machine for driving the rotor.

Preferably, the shaft section has a non-rotationally symmetrical cross section, so that the housing is locked against rotation about the shaft section. This prevents the housing of the brake device from being accidentally twisted relative to the shaft section and can absorb the torque occurring during braking of the wheel. Alternatively or additionally, the shaft section may have a spur that engages with a corresponding gear tooth on the housing to prevent twisting about the shaft section. The spur toothing can be arranged, for example, on a stop of the shaft section against which the brake housing abuts.

According to an advantageous embodiment, it is provided that the second braking element is a housing part of an electric machine, in particular an electric motor, for driving the rotating element, in particular a wheel. The friction surface for mechanically braking the rotating element, in particular the wheel, is therefore an area of the motor housing part. Surface structures, such as fins, are provided on the housing parts, which help to dissipate the heat generated during braking. Preferably, the electric machine is arranged in such a way that: the motor may move the wheel relative to an axle segment or axle support unit of the brake system. The electric motor can be designed, for example, as a hub drive, in particular as a direct drive.

In a particularly preferred manner, the electric machine is designed as an external rotor electric machine and/or has an external rotor, wherein the external rotor is connected to the housing part in a rotationally fixed manner. Advantageously, the housing part is designed to support or represent a rotor sleeve of an outer rotor. The rotor sleeve can form a rotatable element with a supporting and stabilizing effect in order to be able to absorb the forces of the rotating element, in particular of the wheel. Alternatively, the housing part can preferably also be released from the rotating element, in particular the wheel, so that the housing part can be separated from the rotating element, in particular the wheel, in order to be able to replace the housing part in the event of wear, for example due to braking.

Preferably, the electric motor is arranged at least partially inside the rotating element, in particular the wheel, so that in the brake system or the axle bearing unit with two wheels, the region between the two wheels can be used for arranging further components.

In a preferred embodiment, the braking surface is formed by a first brake lining arranged on the first brake element and/or the braking surface is in contact with a second brake lining of the second brake element in the braking position. Preferably, the first brake lining of the first brake element or the second brake lining of the second brake element has a friction mechanism, which is worn out during braking by friction when contacting the counter brake element.

In the case of a design in which the brake lining is formed by a first brake lining, the first brake lining is preferably releasably connected to the first brake element, so that worn brake linings can be exchanged. In a particularly preferred manner, the first brake lining is connected to the first brake element in a form-fitting manner. Preferably, the first brake lining of the first brake element is of annular or cylindrical design, so that the annular brake surface is occupied as completely as possible. Preferably, the first brake lining is arranged on the first brake element and no brake lining is arranged on the second brake element. According to an advantageous embodiment, the first brake lining of the first brake element is designed in a divided manner. For example, the first brake lining can be divided in the following manner: comprising one or more annular ring segments.

In the embodiment in which the braking surface of the first brake element is in contact with the second brake lining of the second brake element in the braking position, the second brake lining is preferably releasably connected to the second brake element, so that worn brake linings can be replaced. Preferably, the second brake lining is connected to the second brake element in a form-fitting manner.

In this case, the brake surface of the first brake element is in contact with the second brake lining in the braking position. An advantage of such a design is that during braking, heat is generated primarily at the braking surface of the first brake element which is in contact with the second brake lining on the second brake element. This reduces the heat generated during braking from acting on the rotating element. It is particularly advantageous if a heat-sensitive device or another heat source, for example an electric motor for driving the rotor, is arranged on the rotor.

The second brake lining of the second brake element is preferably designed in the form of a ring or cylinder. In a particularly preferred manner, the second brake lining is arranged concentrically to the rotational axis of the rotor, so that the effective surface area between the braking surface of the first brake element and the second brake lining of the second brake element is as large as possible during braking.

According to an advantageous embodiment, the second brake lining of the second brake element is designed in a divided manner. For example, the second brake lining can be divided in the following manner, namely: surrounding one or more annular ring segments.

In the case of an embodiment in which the second brake lining is arranged on the second brake element or on the rotating element, in particular on the wheel, it is advantageous if no brake lining is provided on the first brake element, so that the heat generated during braking is introduced almost completely into the first brake element.

Preferably, the first braking element has at least one ventilation opening. Such ventilation holes increase the surface area of the first braking element and may simplify heat conduction from the first braking element to the ambient air.

Preferably, the ventilation holes extend in a direction aligned parallel to the rotational axis of the turning element.

Preferably, the at least one ventilation opening is designed as a through-opening in the first brake element, so that ambient air can enter the through-opening from both open sides thereof, and the air circulation is improved again by the ventilation opening.

It has proven to be advantageous if the first braking element comprises a plurality of ventilation openings. Preferably, vent holes having different cross-sections are designed. As a particularly preferable aspect, the first ventilation hole disposed close to the rotation shaft has a cross section larger than that of the second ventilation hole disposed away from the rotation shaft.

Alternatively or additionally, the ventilation device of the first brake element may have one or more cooling ribs, which likewise increases the surface area of the first brake element.

In one embodiment, the housing has an opening through which the cable can be guided substantially parallel to the axis of rotation, which has proven to be advantageous. The opening can be used to supply and/or control cables for an electric machine, in particular an electric motor, which is arranged at least partially inside the wheel. The shaft carrier unit need not have a hollow shaft section, for example in the form of a hollow shaft, for guiding the motor supply and/or control cables. This has the advantage that a more robust shaft support unit with solid shaft sections can be used.

Preferably, the axle bearing unit has two wheels which are rotatable about the axis of rotation and two braking devices for braking the wheels. Each wheel may have its own motor for driving the respective wheel. Preferably, the electric machine is designed in the manner described above.

The invention also relates to a low-floor vehicle with the shaft support unit. Preferably, the low-floor vehicle is designed as a scooter, mini-scooter or scooter.

In the low-floor vehicle, the same advantages as described for the brake system or the axle stand unit can be achieved.

Preferably, the low floor vehicle has a base body to which one or more axle support units are connected. The base body can be designed, for example, as a tray or as a plate. The base may provide a standing surface for a user of the low-floor vehicle.

A further object of the invention is a drive unit with the aforementioned brake system, wherein the rotating element of the brake system is designed as a drive element, in particular as a drive wheel or drive pinion.

In the drive unit, the same advantages as described for the brake system or the shaft support unit can be achieved. Such drive units can be used, for example, in industrial installations, such as production installations, robots or conveying installations.

Preferably, the drive wheel or the drive pinion is connected to an electric motor, in particular an electric motor, which is arranged in such a way that: the motor may move the drive wheel or the drive pinion relative to a shaft segment of the brake system. The electric motor can be designed, for example, as a hub drive, in particular as a direct drive.

Drawings

Further details and advantages of the invention will be explained below on the basis of embodiments shown in the drawings.

FIG. 1 is a schematic plan view of one embodiment of a low-floor vehicle according to the present invention;

FIG. 2 is a perspective view, partially in section, of one embodiment of the axle support unit with the braking system of the present invention;

FIG. 3 is a first cross-sectional view through the wheel of the axle support unit of FIG. 2, wherein the cut-away level contains the axis of rotation of the wheel;

FIG. 4 is a second cross-sectional view through the wheel of the axle support unit of FIG. 2, wherein the cut-away level is rotated a predetermined angle relative to the cut-away level of FIG. 3;

fig. 5 is a third sectional view through the wheel of the axle support unit of fig. 2, where the sectional level is perpendicular to the axis of rotation of the wheel.

FIG. 6 is a cross-sectional view through a rotor with another embodiment of the shaft support unit of the braking system of the present invention, wherein the cut-away level contains the axis of rotation of the rotor; and

fig. 7 is an exploded view of the braking system shown in fig. 6.

Description of the reference numerals

1 low-floor vehicle 2 base body 3 standing surface 4 axle support unit 5 wheel 6 axle segment 7 tilting means 8 motor 9 second brake element 10 brake means 11 housing 11.1 cavity 12 brake piston 13 first brake element 14 brake surface 15 sealing element 16 spring element 17 opening 18 cable 19 fluid interface 20 bearing 21 exhaust interface 23 type mating element 30 brake system 31 vent 32 vent 33 brake lining D rotating shaft.

Detailed Description

Fig. 1 shows a schematic plan view of an embodiment of a low-floor vehicle 1 according to the invention, wherein the vehicle is designed as a scooter. The vehicle 1 has a base body 2, which is designed as a tray and the front side of which provides a standing surface 3 for a user of the vehicle 1. Exactly two axle carrier units 4 are arranged on the rear side of the base body 2 opposite the front side, and are of double-rail design, i.e. each axle carrier unit 4 contains exactly two wheels 5. In an embodiment, the wheels 5 are designed as rollers, for example hard rubber rollers or polyurethane rollers. The axle carrier units 4 each have two axle segments 6, wherein each axle segment 6 supports a wheel 5. The shaft support units 4 are each connected to the base body 3 by a tilting device 7. The tilting device 7 allows the axle bearing unit 4 to tilt or deflect relative to the base body 2, so that the vehicle 1 can be moved into a curve by the weight of the driver on the standing surface 3.

Fig. 2 shows an embodiment of an axle carrier unit 4 that can be used as, for example, a rear axle in the low-floor vehicle 1 shown in fig. 1. Alternatively or additionally, such a bearing unit 4 can also be used as a front axle of the vehicle 1. The axle bearing unit 4 has two wheels 5 which are rotatable about a rotational axis D, wherein each of the two wheels 5 is assigned a brake device 10 for braking the respective wheel 5. The wheels 5 are each arranged on one of the two axle portions 6 of the axle bearing unit 4 in a rotatable manner. The braking device 10 comprises a first braking element 13 which is movable between a rest position shown in fig. 2, 3 and 4, in which an annular braking surface of the first braking element 13 is arranged concentrically to the axis of rotation D of the wheel 5 and away from the wheel 5, and a braking position, in which the braking surface 14 of the first braking element 13 is in contact with a second braking element 9 connected in a rotationally fixed manner to the wheel 5. In the rest position, the braking surface 14 of the first brake element 13 is spaced apart from the wheel 5, so that the first brake element cannot play a role in delaying the rotational movement of the wheel 5. Conversely, when the braking surface 14 of the first brake element 13 is in contact with the second brake element 9, the rotational movement of the wheel 5 can be delayed by the annular braking surface.

In this connection, the axle bearing unit 4 comprises two brake systems 30, wherein the rotating elements are each designed as a wheel 5.

In order to distribute the pressure required for braking as evenly as possible, the first brake element 13 can be moved hydraulically between a rest position and a braking position. The risk of overloading in individual regions of the wheel 5 or of the wheel bearing arrangement can thereby be reduced, so that the service life of the vehicle can be extended. The braking surface 14 is formed by a brake lining arranged on the first brake element 13.

As shown in fig. 3, the brake device 10 is designed in the form of a hydraulic clutch brake. The brake device 10 has a hollow-cylindrical brake piston 12 which is connected to a first brake element 13 and is mounted in a housing 11 having a hollow-cylindrical interior 11.1 for receiving hydraulic fluid. The interior 11.1 is sealed by a sealing element 15 connected to the brake piston 12. The housing 11 is clamped on the shaft section 6 of the shaft support unit 4 and is arranged in a concentric manner with the rotation axis D of the wheel or the shaft section 6. On the side of the housing 11 facing the wheel 5, a spring element 16 is arranged, by means of which the brake piston 12 is prevented from accidentally sliding out of the housing 11. The spring element 16 is of substantially annular design.

According to an exemplary embodiment, the second brake element 9 is a housing part of the electric motor 8 for driving the wheel 5, which housing part is connected to the wheel in a rotationally fixed manner. The electric machine 8 is designed as an electric motor and has a stator which is firmly connected to the shaft section 6 and a rotor which is rotatable relative to the stator and which is connected in a rotationally fixed manner to the second brake element 9 and to the wheel. In order to rotatably support the wheel 5 and the second brake element 9, a first bearing 20 is provided on the inner side of the wheel 5 and a second bearing 21 is provided on the outer side of the wheel 5. The first bearing 20 and/or the second bearing 21 are designed as rolling bearings. The motor 8 is arranged substantially inside the wheel 5. In addition, the housing 11 has an opening 17 through which a cable 18 can be guided parallel to the axis of rotation D, which is only partially shown in fig. 3. The electric motor 8 can be supplied with electric energy and/or be electrically controlled via a cable 18. When mounting the spindle bearing unit 4, the brake device 10 is first pushed onto the spindle section 6 until the housing comes into contact with the stop of the spindle section, see fig. 4. If necessary, the electric motor 8 together with the wheel 5 is pushed onto the shaft section 6 in a further step until the electric motor 8 comes into contact with the housing 11 of the brake device 10. In the mounted state, the annular stop region of the electric motor 8 is accommodated in an accommodation region on the inner contour of the housing 11.

A hydraulic pressure can be exerted on the brake piston 12 and thus on the first brake element 13 by the hydraulic fluid present in the interior 11.1. As shown in fig. 4, the housing 11 has a fluid connection 19 for introducing hydraulic fluid. In addition, an exhaust port 22 is provided.

Fig. 5 shows a section through the wheel 5 of the axle bearing unit 4, wherein the section plane is arranged perpendicular to the axis of rotation D of the wheel 5. It can be seen that the annular braking surface 14 of the first braking element 13 is arranged in a concentric manner with the rotation axis D of the wheel 5. The braking surface can be designed, for example, as a brake lining, which is arranged on the surface of the first brake element 13 facing the second brake element 9. The first brake element 13 is of substantially annular design and has a form-fitting element 24 on an inner contour facing the housing 11. The type-fitting elements 24 are designed as teeth adjacent in the circumferential direction of the inner contour and correspond to the second type-fitting elements 23 arranged on the outer contour of the housing 11. The first and

second type counter-elements

23, 24 provide a rotation protection against an accidental rotation of the first braking element 13 relative to the housing 11. The first and second type of

co-operating elements

23, 24 simultaneously allow the first braking element 13 to perform a guiding movement with respect to the housing 11 along a direction parallel to the rotation axis D of the wheel 5.

The shaft section 6 accommodating the wheel 5 additionally has a rotationally asymmetrical cross section, which has the advantage that the housing 11 is locked against rotation about the shaft section 6.

Fig. 6 and 7 show another embodiment of the braking system 30. The brake system 30 shown in fig. 6 may be provided as an integral part of the axle support unit 4, which may be used, for example, as a rear axle in the low-floor vehicle 1 shown in fig. 1. Alternatively or additionally, such a bearing unit 4 can also be used as a front axle of the vehicle 1.

The brake system 30 has a rotary element which is rotatable about a rotational axis D and which is designed as a wheel. The wheel 5 is rotatably arranged on a shaft section 6 of the brake system 30. A further component of the braking system 30 is a braking device 10 with a first braking element 13 which is movable between a rest position shown in fig. 6, in which an annular braking surface 14 of the first braking element 13 is arranged concentrically with the axis of rotation D of the wheel 5 and remote from the wheel 5, and a braking position, in which the braking surface 14 of the first braking element 13 is in contact with a second braking element 9 connected in a rotationally fixed manner to the wheel 5. In the rest position, the braking surface 14 of the first brake element 13 is spaced apart from the wheel 5, so that the first brake element 9 cannot play a role in delaying the rotational movement of the wheel 5. Conversely, when the braking surface 14 of the first brake element 13 is in contact with the second brake element 9, the rotational movement of the wheel 5 can be delayed by the annular braking surface 14.

In order to distribute the pressure required for braking as evenly as possible, the first brake element 13 can be moved hydraulically between a rest position and a braking position. The first brake element 13 is of substantially annular design and has a form-fitting element 24 on an inner contour facing the housing 11. The type-fitting elements 24 are designed as teeth adjacent in the circumferential direction of the inner contour and correspond to the second type-fitting elements 23 arranged on the outer contour of the housing 11. The first and

second type counter-elements

23, 24 provide a rotation protection against an accidental rotation of the first braking element 13 with respect to the housing 11. The first and second type-

fitting elements

The brake system 30 corresponds substantially to the brake system shown in fig. 2 to 5, with the difference that no brake lining is arranged on the first brake element 13. However, the brake lining 33 is arranged on the surface of the second brake element 9 facing the first brake element 13. The brake lining 33 is of substantially annular design and is accommodated in an annular recess of the second brake element 9. The connection between the brake lining 33 and the second brake element 9 is releasable, so that the brake lining 33 can be replaced when necessary, for example when a certain degree of wear has been reached.

In addition, in the exemplary embodiment shown in fig. 6 and 7, the first brake element 13 is designed in one piece with the brake piston 12.

The brake lining 33 comprises a friction mechanism which is in contact with the braking surface 14 of the first brake element 13 when the first brake element 13 is in the braking position. During braking, the friction between the braking surface 14 and the brake lining 33 results in a heat release mainly at the braking surface 14 of the first brake element 13. Another heat source is the motor 8 for driving the wheel 4. The electric machine 8 is designed as an electric motor and has a stator which is firmly connected to the shaft section 6 and a rotor which is rotatable relative to the stator and which is connected in a rotationally fixed manner to the second brake element 9 and to the wheel, see also the corresponding description in relation to the embodiment shown in fig. 2-g.

In order to facilitate the dissipation of the heat generated during braking from the first brake element 13 into the ambient air, the first brake element is designed from a material with high heat-conducting properties, for example a metal, in particular steel. In addition,

ventilation openings

31, 32 are provided in the first brake element 13, which increase the surface area of the first brake element 13 and thus also improve the heat exchange with the ambient air. The ventilation holes 31, 32 extend in a direction aligned parallel to the rotation axis D of the wheel 5. In addition, the

ventilation openings

31, 32 are also designed as through-openings in the first brake element 13, so that in the rest position of the first brake element 13 shown in fig. 6, air can flow into the through-openings through both openings. In the braking position, the through-opening can be ventilated through an opening on the side of the first braking element 13 facing away from the second braking element 9.

The ventilation holes 31, 32 are arranged on a plurality of virtual circumferential lines arranged in a concentric manner with the rotation axis D. The ventilation holes 31, 32 have different drilled cross sections. Preferably, the vent holes 31, 32 arranged on the same virtual circular line have the same drilled cross section. As a particular preference, the drilled cross section of the ventilation holes 31 arranged close to the axis of rotation D is larger than the drilled cross section of the ventilation holes arranged remote from the axis of rotation D.

The low-floor vehicle 1 of the scooter type described above comprises an axle carrier unit 4 with at least one wheel 5 rotatable about an axis of rotation D and a brake device 10 for braking the wheel 5, wherein the brake device 10 has a first brake element 13 which is movable between a rest position in which an annular braking surface 14 of the first brake element 13 is arranged concentrically with respect to the axis of rotation D of the wheel 5 and remote from the wheel 5, and a braking position in which the braking surface 14 of the first brake element 13 is in contact with the wheel 5 or with a second brake element 9 connected in a rotationally fixed manner to the wheel 5, wherein the first brake element 13 is hydraulically movable between the rest position and the braking position. The first brake element 13 is connected to a hollow-cylindrical brake piston 12 which is mounted in a housing 11 having a hollow-cylindrical interior 11.1 for receiving hydraulic fluid. In addition, the first braking element 13 is of annular design and has, on the inner contour, first-type counter-elements 24 which interact with second-type counter-elements 23 on the outer contour of the housing 11 in such a way that: the rotation of the first braking element 13 about the axis of rotation D is locked but can be moved parallel to the axis of rotation D.

According to a variant of the embodiment shown, the braking system 30 can be part of a drive unit having a rotary element designed as a drive wheel or drive pinion. Such a drive unit can be used, for example, in industrial installations, in particular in manufacturing installations, manufacturing robots or transport installations.

Claims

1. A braking system (30) with a rotary element (5) which is rotatable about a rotation axis (D) and with a braking device (10) for braking the rotary element (5), wherein the braking device (10) has a first braking element (13) which is movable between a rest position, in which a braking surface (14) of the first braking element (13) is arranged concentrically to the rotation axis (D) of the rotary element (5) and remote from the rotary element (5), and a braking position, in which the braking surface (14) of the first braking element (13) is in contact with the rotary element (5) or with a second braking element (9) which is connected in a rotationally fixed manner to the rotary element (5), the second braking element (9) being a housing part of an electric motor (8) for driving the rotary element (5), wherein the first brake element (13) is hydraulically movable between the rest position and the braking position, wherein,

the first brake element (13) is connected to a hollow-cylindrical brake piston (12) which is mounted in a housing (11) having a hollow-cylindrical interior (11.1) for receiving hydraulic fluid,

it is characterized in that the preparation method is characterized in that,

the first braking element (13) is designed in a ring shape and has, on the inner contour, a first-type counter-element (24), in particular a plurality of teeth or wedges, which co-operate with a corresponding second-type counter-element (23) on the outer contour of the housing (11) in such a way that: the first braking element (13) is locked for rotation about the axis of rotation (D) but is movable parallel to the axis of rotation (D).

2. A braking system (30) according to claim 1, characterized in that said housing (11) is clamped on a shaft section (6) of said braking system.

3. A braking system (30) according to claim 2, characterized in that the shaft section (6) has a non-rotationally symmetrical cross-section such that the housing (11) is locked around the twisting of the shaft section (6); and/or the shaft section (6) has a spur toothing which engages with a corresponding toothing on the housing (11) in order to prevent twisting about the shaft section (6).

4. Braking system (30) according to claim 1, characterized in that the electric motor (8) is arranged at least partially inside the rotating element (5).

5. Braking system (30) according to claim 1, characterized in that the braking surface (14) is constituted by a first brake lining arranged on the first brake element (13).

6. A braking system (30) according to any one of the preceding claims 1 to 5, characterized in that the braking surface (14) is in contact with a second brake lining of the second brake element (9) in a braking position.

7. A braking system (30) according to claim 1, characterized in that the first braking element (13) has at least one ventilation hole (31, 32).

8. A braking system (30) according to claim 7, characterized in that said ventilation holes (31, 32) extend along a direction aligned parallel to the rotation axis (D) of said rotating element (5).

9. A braking system (30) according to claim 8, characterized in that the at least one ventilation hole (31, 32) is designed as a through hole in the first braking element (13).

10. Braking system (30) according to any one of claims 7 to 9, characterized in that said first braking element comprises a plurality of ventilation holes (31, 32) designed with different cross sections, wherein a first ventilation hole (31) arranged close to said rotation axis (D) has a cross section greater than a second ventilation hole (32) arranged far from said rotation axis (D).

11. A braking system (30) according to claim 1, characterized in that the housing (11) has an opening (17) through which a cable (18) can be guided substantially parallel to the axis of rotation (D).

12. Axle support unit (4) for a low-floor vehicle with a brake system (30) according to one of the preceding claims, wherein the rotating element (5) of the brake system is designed as a wheel.

13. The axle bearing unit according to claim 12, characterized in that there are two rotating elements (5) designed as wheels, which are rotatable about a rotation axis (D), and two braking devices (10) for braking the wheels.

14. A low-floor vehicle (1), in particular a scooter, with an axle support unit (4) according to any one of claims 12 or 13.

15. Drive unit with a brake system (30) according to one of claims 1 to 11, wherein the rotating element (5) of the brake system (30) is designed as a drive element.