DE102022106487A1 - Drum brake and method for operating a drum brake - Google Patents

Abstract

The invention relates to a drum brake, in particular a drum brake for an electric motor-driven vehicle, comprising a brake drum rotatably mounted about an axis of rotation, a base plate fixed relative to the brake drum and at least one partially movable brake element, the brake drum having at least one plate section and a rim section transverse thereto, wherein at least one gas inlet opening and at least one gas outlet opening are provided, and at least one internal cooling gas path running in the brake drum is arranged between the gas inlet opening and the gas outlet opening. Furthermore, the invention includes an electric wheel hub drive which includes such a drum brake and/or is directly coupled to it.

Description

Field of invention

The invention relates to a drum brake with a cooling gas guide according to the preamble of claim 1, and a wheel hub motor comprising this drum brake according to the preamble of claim 10.

Background of the invention

Mechanical drum brakes are known in the art and are used in particular in wheel hub drives. Such a drum brake is from the DE 102012211522 A1 known, which discloses a friction or service brake for a vehicle wheel of a vehicle that can be driven and braked by means of an electric motor. The friction brake comprises a friction element attached to the rotor and at least one braking device attached to the stator, wherein the braking device can be pressed against a friction section of the friction element for braking.

Furthermore, the reveals WO 2013/026659 A1 For example, a wheel hub drive for an electrically driven vehicle, in which the rotor on the drive wheel is arranged radially within the stator, the wheel hub motor disclosed being a so-called internal rotor. The stator is screwed to a stator plate and is held in position by it. The stator plate is attached to the axle journal of the wheel bearing, but also carries the brake cylinder of the drum brake, which contains a pressurization connection and a vent for the hydraulically controlled brake cylinder. The disadvantage is that the drum brake is heavily enclosed and therefore thermally shielded, so that the drum brake quickly overheats.

Task

The object of the invention is therefore to provide an improved drum brake that is less prone to overheating. It is still the object of the invention to provide one

This object is achieved by a drum brake according to the characterizing features of claim 1 and a wheel hub drive according to the characterizing features of claim 10, which includes the drum brake.

Summary of the invention

The drum brake is in particular a drum brake for an electric motor-driven vehicle and comprises a brake drum rotatably mounted about an axis of rotation, a base plate fixed relative to the brake drum and at least one brake device which can be moved partially or in elements, the brake drum itself having at least one plate section and a rim section which is transverse thereto . Here, at least one gas inlet opening and at least one gas outlet opening are provided, which lead into the interior of the brake drum, and at least one internal cooling gas path running in the brake drum is arranged between the gas inlet opening and the gas outlet opening.

Here, the term cooling gas path is also to be understood as meaning a flow path which is divided into a large number of individual flow paths over a section.

The interior of the brake drum is essentially determined by the fixed base plate, the opposite plate section and the radially outer ring section.

Overall, the actual braking mechanism can be designed to reduce kinetic energy and reduce the speed of, for example, a motorcycle or a passenger car, in particular as a so-called simplex or duplex brake or a comparable braking system. The drum brake is therefore also functionally constructed in an analogous manner or is connected or can be connected to associated or adjacent components in a mechanical, fluid, data and/or current-conducting manner.

An advantageous embodiment can consist of the gas inlet openings or their flow cross section being arranged and aligned in such a way that cooling gas sucked in from the outside is guided into the interior parallel to the axis of rotation.

Although the term “cooling gas” is used here, this is not to be understood as restrictive and generally means (atmospheric) “air” and/or an “air/gas mixture” in the respective composition as it occurs during intended operation and depending on the location is available.

A further improvement can be that one or more wing elements are arranged in the brake drum, by means of which the cooling gas sucked in via the at least one gas inlet openings is transported to the inner cooling gas path is directed radially outwards to the axis of rotation. An improvement here can be that a large number of wing elements are provided, which are arranged in particular symmetrically, in a star shape, around the axis of rotation.

In a further improved variant, it can be provided that the wing elements arranged in the brake drum are connected to the brake drum, in particular the plate section, at least with a partial surface or outer edge and are mounted so that they can rotate together.

An advantageous shape of the wing elements can consist in that the at least one wing element comprises an input end with an input section, an intermediate section and an outlet end with an outlet section, the input end pointing in the direction of the gas inlet opening and the outlet end pointing in the direction of the gas outlet opening.

An improvement may be that the input section is angled or curved, as a type of axial blade, and/or the outlet section is angled or curved, as a type of radial blade.

An improvement here can be that the input section is inclined, angled and/or curved about an axis running vertically to the axis of rotation and/or the outlet section is inclined, angled and/or curved about an axis running parallel to the axis of rotation.

The main direction of rotation should be defined in the present case by the fact that it results from the direction of travel of a vehicle that is moved forward (forward) during normal operation and/or which, from a statistical point of view, is the more common direction of rotation of the brake drum when the vehicle is being used.

In an improved embodiment of the brake, it can be provided that the gas inlet opening directs cooling gas coming from outside in a first flow direction through the gas inlet opening into the interior, wherein the gas outlet opening directs the cooling gas in a flow direction second to the first flow direction, which is different from the first flow direction. In this way, the heated cooling gas coming from the interior can be directed and released away from the inflowing cooling gas.

In the further improved variant, the second flow direction determined by the gas outlet opening can be parallel to the first flow direction, but run in the opposite direction. In other words, the respective flow cross sections are parallel to one another, but are arranged, for example, at different radial distances from the axis of rotation.

In the present case, the direction of flow of the cooling gas in connection with an opening of the internally cooled drum brake is to be understood as the orientation (vector) that is perpendicular to the cross-sectional or passage area of the opening, which can be described using the hydraulic diameter.

In an advantageous embodiment, it can be provided that the brake drum has at least one outlet channel, the input side of which faces the interior of the brake drum, and on the output side of which the gas outlet opening is arranged or this includes the gas outlet opening. In a further improved version, the at least one outlet channel can be an integral part of the rim section of the brake drum, which is arranged at least over a section on and/or in the rim section.

A further improved embodiment can have a plurality of outlet channels, which are advantageously aligned parallel to one another. In one embodiment, these many outlet channels can be fluidly connected to the interior of the brake drum via a common ring channel or ring channel section on the input side.

Overall, it can be advantageous if the gas outlet openings point away from the standing base plate and/or are arranged radially above the base plate and/or the base plate has recesses or passage openings in the area of the gas outlet openings.

The heat dissipation can be further improved by arranging a cooling fin on the radially outer side of an outlet channel or by arranging cooling fins in the area of several outlet channels on their radially outer side or on the common outer surface.

In a further, improved embodiment, a current-carrying element can be provided in the interior of the brake drum, in particular a fixed current-carrying element. This can advantageously be attached to the base plate or represent a section of material formed from the base plate.

A good embodiment can provide that this current-carrying element is funnel-shaped and is separated from the at least one Gas inlet opening expands radially outwards to the gas outlet openings or an annular channel leading there. The wing elements are advantageously designed to be complementary with the free edge opposite the current-carrying element. In particular, the gap between the current-carrying element and a wing element is smaller than 10 mm, advantageously in the range of 0.5 to 5 mm and ideally in the range of 0.5 to 2 mm.

The cooling effect is particularly pronounced the smaller the gap distance is, whereby there must be no contact between a wing element and the current-carrying element, even under all tolerances, thermal expansions and vibrations.

Thus, in an advantageous embodiment, when the brake drum is rotating, a first annular space can be formed in the interior of the brake drum, which is adjacent to the at least one gas inlet opening and has a first (central) radius. Furthermore, in this variant, a second annular space adjacent to the at least one gas outlet opening is formed, which has a second radius, the first radius being smaller than the second radius. Here, the first radius is equal to or a maximum of 10 mm larger than the radius of the hub section of the brake drum and the second radius is equal to or a maximum of 10 to 20 mm smaller than the outer radius of the rim section.

With rotating wing elements, the centrifugal forces drive the sucked-in cooling gas radially outwards, guided through the wing elements and there it is directed to the gas outlet openings, an upstream annular channel and/or through the outlet channels at increased pressure and discharged to the outside.

The invention also includes a wheel hub drive, in particular for a vehicle, such as a passenger car or truck, a two- or three-wheeler, an AGV (automous guided vehicle) or a comparable vehicle, which has an electric motor (drive motor) that can be arranged within a wheel rim , with the wheel hub aligned in the direction of rotation. This includes a drum brake according to one of the above-mentioned embodiments. The electric motor (drive motor) can in particular have a drive rotor that can be connected at least indirectly to a wheel hub and a fixed drive stator that can be supplied with current. Alternatively, in a wheel hub drive with a non-coaxial gear, but rather a simple spur gear, the brake drum and the wheel rim or the vehicle wheel cannot be on the same axis.

In an improved embodiment of the wheel hub drive, the fixed base plate and the drive stator can be arranged or connected at least indirectly to a common stator device in a rotationally fixed manner.

The wheel hub drive can have a plate gear. However, it can in particular also be or include an electric direct drive, in which the wheel rim or tire is driven without a gear ratio, for example in the form of a gear. The rotational speed of the drive motor and the driven wheel is synchronous at all times.

The electric direct drives based on permanently excited synchronous motors enable very high efficiency.

The drive stator and drive rotor of the electric motor are connected to the fixed part of the wheel bearing or the wheel hub, which leads to a very compact and space-saving arrangement.

Short description of the drawing

• 1 in einer vertikalen Schnittdarstellung auf der Ebene der Rotationsachse ein Ausführungsbeispiel der Trommelbremse,
• 2 die Ausführungsform der 1 als perspektivische und teilweise geschnittene Darstellung und
• 3 die Trommelbremse nach 1 und 2 in ihrer Einbaulage in bzw. gemeinsam mit einem zugeordneten Radnabenantrieb.

The invention is explained in more detail below using two exemplary embodiments. Show it:

• 1 in a vertical sectional view on the plane of the rotation axis an embodiment of the drum brake,
• 2 the embodiment of the 1 as a perspective and partially sectioned representation and
• 3 the drum brake 1 and 2 in its installation position in or together with an assigned wheel hub drive.

Detailed description of the drawing

In the sectional view of the 1 a drum brake 10 according to the invention is shown for a vehicle, not shown. The drum brake 10 comprises a brake drum 12 rotatably mounted about the horizontally aligned axis of rotation 100, a fixed base plate 13 opposite the brake drum 12. The base plate 13, also called an anchor plate, is attached to a terminal end plate 4 of the wheel hub 3. The actual braking device 14 is arranged in the interior 17 of the brake drum 12, which is not shown with all the associated details here and corresponds to a hydraulic simplex brake. As is common with drum brakes, one or more brake shoes can press against the inner surface of the ring element 16 are pressed to initiate the braking process or to ensure standstill.

The brake drum 12 has a vertically aligned plate section 15 and an outer ring section 16 aligned parallel to the rotation element 100. The interior 17 of the brake drum 12 is an annular space which is delimited towards the wheel hub 3 by the hub section 18. The necessary elements of mechanical storage and rotation are not shown.

Three gas inlet openings 20 are formed in the end plate 4 of the wheel hub 3 and the base plate 13 of the drum brake 10, through which cooling gas can flow into the interior 17, which flows through the interior 17 on an inner cooling gas path 21, which is indicated as a dashed arrow. These gas inlet openings 20 are arranged symmetrically relative to the axis of rotation 100 in a first radius R1. The gas inlet opening 20 and thus also this first radius R1 are arranged directly above the hub section 18, so that incoming cooling gas flows in virtually tangentially along the inside of the hub section 18.

The cooling gas path 21 leads through the interior 17 to an annular channel 33, which is arranged circumferentially in the interior 17 in the transition from the plate section 15 to the ring section 16. On the entire circumference in the wall of the ring section 16, a large number of outlet channels 23 are arranged parallel to one another and parallel to the axis of rotation, the input side 23.1 of which lies in the transition to the annular channel 33 or forms it and the output sides 23.2 of which lead to or form gas outlet openings 22. The gas outlet openings 22 are arranged at a radius R2 from the axis of rotation 100, which largely corresponds to the average radius of the ring section 16.

The arrangement of the gas outlets 22 and/or the outlet channels 23 in the ring section 16 comprising the friction surface leads to particularly effective cooling of the drum brake.

The brake drum 12 has a plurality of symmetrically arranged wing elements 24, which are attached with one edge to the hub section 18 and to the plate section 15 and rotate together with the brake drum 12. The outer edge of the wing elements 24 is adapted to the shape of the funnel-like opening current-carrying element 19 and faces it with a small gap of less than 2 mm. For further improved cooling, parallel cooling fins 27 are arranged on the outer circumference of the ring section 16.

The geometry of the wing elements 24 and the cooling gas path 21 are in the 2 presented in detail. Three kidney-shaped gas inlet openings 20 are arranged in the end plate 4.

The ten to twelve wing elements 24 arranged on the circumference of the hub section 18 and in the interior 17 have at the respective input end 28 an input section 29 which is angled like a blade in the main direction of rotation 103 (axial blade), which extends into an intermediate section 32 which is essentially parallel to the axis of rotation 100 and projects radially transforms. This intermediate section 32 is adjoined by an outlet section 31, with the outlet end 30 pointing against the main direction of rotation 103. The outlet section 31 is inclined to a large radius against the main direction of rotation 103 (radial blade), which ensures good flow guidance in the respective compartments created by the wing elements 24.

In an alternative embodiment, not shown, for example, the lower edge of the intermediate section 32 is not aligned parallel to the axis of rotation 100, but is inclined at an angle of 5 to 30 °, that is, inclined against the main direction of rotation 103.

In the 2 It is also shown that the base plate 13 has recesses or opening windows in the area of the gas outlet openings 22 arranged and circumferential in the radius R2, so that the heated cooling gas (air) can flow out largely unhindered.

Furthermore, in the 2 Further components of the braking device 14 are shown, such as the hydraulic cylinder 14.1, the return spring 14.2, a jaw joint 14.3 and the friction surface 14.4 on the ring section 16.

The sectional view of the 3 shows the drum brake 10 1 and 2 in its installation position in or together with an associated wheel hub drive 1 and the associated electric drive motor 6, which is arranged on the wheel hub 3 and in the wheel rim 2. The wheel hub motor 1 is installed in a housing. On the side facing the vehicle there is also a supply connection 9 for energizing the drive motor 6, although not all necessary or usual mechanical, fluidic and / or conductive (data, power) connections are shown. The drive motor 6 acts on the wheel rim 2 and thus on the tire 5 via a planetary gear 8. The brake drum 12 of the drum brake 19 is rotated via a clutch connection 11, which is only indicated schematically.

Reference number list

1

Wheel hub drive

2

wheel rim

3

wheel hub

4

End plate

5

Tires

6

Drive motor, electric motor

8th

Planetary gear

9

Supply connection

10

drum brake

11

Coupling connection

12

brake drum

13

base plate

14

Braking device

14.1

Hydraulic cylinder

14.2

return spring

14.3

cheek joint

14.4

friction surface

15

plate section

16

Wreath section

17

inner space

18

Hub section

19

Current-carrying element

20

Gas inlet opening

21

Cooling gas path

22

Gas outlet opening

23

Exhaust channel

23.1

Entrance page

23.2

Home page

24

Wing elements

27

cooling fin

28

Entrance end

29

Entrance section

30

Omission ends

31

outlet section

32

Intermediate section

33

Ring channel

100

Axis of rotation

101

Flow direction, first

102

Flow direction, second

103

Main direction of rotation

R1

radius

R2

radius

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102012211522 A1 [0002]
• WO 2013026659 A1 [0003]

Claims (11)

Drum brake (10), in particular drum brake for an electric motor-driven vehicle, comprising a brake drum (12) rotatably mounted about an axis of rotation (100), a base plate (13) fixed relative to the brake drum (12) and at least one partially movable braking device (14), wherein the brake drum (12) has at least one plate section (15) and a rim section (16) transverse thereto, characterized in that at least one gas inlet opening (20) and at least one gas outlet opening (22) are provided, and wherein between gas inlet opening (20) and Gas outlet opening (22) at least one inner cooling gas path (21) running in the brake drum (12) is arranged. Brake after Claim 1 , characterized in that cooling gas can be sucked in parallel to the axis of rotation via the gas inlet openings (20). Brake after Claim 1 or 2 , characterized in that wing elements (24) are arranged in the brake drum (12), by means of which the cooling gas sucked in via the at least one gas inlet openings (20) is directed radially outwards on the inner cooling gas path (21) to the axis of rotation (100). Brake after Claim 3 , characterized in that the wing elements (24) arranged in the brake drum (12) are connected to at least one partial surface (25, 26) and are mounted so that they can rotate together. Brake according to one of the preceding claims, characterized in that the gas inlet opening (20) conducts cooling gas in a first flow direction (101), the gas outlet opening (22) and/or an outlet channel (23) directing the cooling gas in a flow direction (101) relative to the first flow direction (101). second flow direction (102), which is different from the first flow direction. Brake after Claim 5 , characterized in that the second flow direction (102) determined by the gas outlet opening (22) is parallel to the first flow direction (101), but runs in the opposite direction. Brake according to one of the preceding claims, characterized in that the brake drum (12) has at least one outlet channel (23), the input side (23.1) of which faces the interior (17) of the brake drum (12) and the gas outlet opening on the output side (23.2). (22) is arranged. Brake after Claim 7 , characterized in that the at least one outlet channel (23) is an integral part of the rim section (16) of the brake drum (12), the at least one outlet duct (23) being arranged at least over a section on and/or in the rim section (16). . Brake according to one of the preceding claims, characterized in that a current-carrying element (19) is provided in the interior (17) of the brake drum (12), in particular a non-rotatable current-carrying element (19). Wheel hub drive (1), in particular for a vehicle, comprising a drive motor (6) which can be arranged within a wheel rim (2), the drive motor (6) having a drive rotor (8) which can be connected at least indirectly to a wheel hub (3) and a fixed drive rotor (8) which can be supplied with current Drive stator (7), wherein the wheel hub (3) is aligned in the direction of the axis of rotation (100), characterized in that a drum brake (10) is included, which is designed according to one of the preceding claims. Wheel hub drive (1). Claim 10 , characterized in that the fixed base plate (13) and the drive stator (7) are at least indirectly arranged and/or connected in a rotationally fixed manner on a common stator device.

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