ZA200503844B

ZA200503844B - Wheel hub.

Info

Publication number: ZA200503844B
Application number: ZA200503844A
Authority: ZA
Inventors: Ernst Auer
Original assignee: Naf Neunkirchener Achsenfabrik
Priority date: 2004-05-14
Filing date: 2005-05-12
Publication date: 2006-02-22
Also published as: ES2309418T3; EP1595762A1; PL1595762T3; ATE399689T1; EP1595762B1; DE502004007484D1

Abstract

The wheel hub (10) is assembled of a brake unit comprising a set of stationary (14) and a set of movable disks (16), an outer hub (18) and a brake housing (20), forming a space (22) for the multi-disk unit (12). A coolant is moved inside the inner space (22, 36). The outer hub (18) is provided with a collar (24) at its outer contour with several openings (26) for the insertion of bolts (28). The bolts (28) are no longer accommodated partly inside the housing (20), resulting in an increase of the space available for the coolant.

Description

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WHEEL HUB

} DESCRIPTION:

The present invention relates to a wheel hub for an axle of a motor vehicle or ‘ truck, especially for axles of construction-site trucks and off-road vehicles or tipping trucks, including a multi-disk brake consisting of plural disk-shaped outer plates and corresponding disk-shaped inner plates as well as an outer hub and a brake housing, forming an encapsulated housing with a space for the multi-disk : brake, wherein the encapsulated housing is formed in the interior such that

Circulation of cooling fluid located therein occurs in the space.

Such wheel hubs are known. Especially, from DE 196 24 288 C1, an axle for a wheel dredger having a multi-disk brake in the wheel hub is known, which has the above-mentioned characteristics. However, the wheel hub described there is disadvantageous in that the used multi-disk brake is not adapted to higher velocities. In wheel dredges, this does not result in a problem, since they move only with very low velocities. However, with higher velocities, higher braking moment is required. In multi-disk brakes, this can only be achieved by a higher number of plates. However, the higher the number of plates, the higher also the temperatures within the multi-disk brake or the cooling fluid surrounding the multi- disk brake, respectively, particularly arising in idling or in the unbraked state, respectively. Up to now, this problem has only be solved inadequately.

Therefore, it is the object of the present invention to provide a wheel hub with a multi-disk brake of the initially mentioned type, wherein the multi-disk brake develops only very little temperature especially in idling or in the unbraked state, respectively.

This object is solved by a wheel hub including the features of the independent .claim 1.

Advantageous developments are described in the respective dependent claims.

2 - S-2005/G3844

In a wheel hub according to the invention for an axle of a motor vehicle or truck, ‘ especially for axles of construction-site trucks and off-road vehicles or tipping ‘ trucks, the used multi-disk brake is comprised of plural disk-shaped outer plates ) 5 and corresponding disk-shaped inner plates as well as an outer hub and a brake . housing forming together an encapsulated housing with a space for the multi-disk brake, wherein the encapsulated housing is formed in the interior such that circulation of a cooling fluid located therein occurs in the space. Therein, the outer hub has an at least partially surrounding collar projecting outwardly of the outer hub, wherein plural openings for respectively receiving a wheel bolt for connecting the outer hub to a rim of a wheel are formed in the region of the collar. By this construction according to the invention it is possible to significantly increase the available space for the multi-disk brake. Especially, the wheel bolts no longer protrude into the hub housing, as is the case in the prior art, but are located outside of the hub housing. By increasing this Clearance, improved circulation of the cooling fluid, especially oil, located in the space is achieved. Compared to the multi-disk brakes known up to now, temparature decrease of ca. 10 to 25°C in idle mode or unbraked state, respectively, resuits. By these low idle temperatures, additionally, it is no longer required to provide additional cooling for the multi-disk brake. Compared to conventional disk brakes, the multi-disk brake is largely free from maintenance, since no wear occurs. Especially, no braking dust arises.

Further, the multi-disk brake is guided in the cooling fluid, especially-oil. Since the specific heat absorption of the oil is several times higher than with iron, with the same weight, remarkably higher thermal capacity results compared to a known disk brake of iron. Thereby, the wheel hub according to the invention can be designed smaller and more lightweight as a whole.

In an advantageous development of the wheel hub according to the invention, the inner plates constitute the fixed portion and the outer plates constitute the rotating | portion of the multi-disk brake, wherein the inner plates are connected to a fixed inner hub through a suppart member in rotationally fixed and axially displaceable manner, and the outer plates are connected to the radially outward, rotating outer hub in rotationally fixed and axially displaceable manner. Therein, the outer plates co CS Le 3005/0%5 40 have radially outward recesses, which engage with plural bolts axially attached between outer hub and brake housing. Thereby it is ensured that the outer plates ‘ are formed in rotationally fixed, but axially displaceable manner, and move reliably ) together with the rotating brake housing and the outer hub.

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In another advantageous development of the invention, for the cooling fluid circulation, a distribution space is formed between an inner side of the brake ’ housing and the bolts. Additionally, it is possible that blade-like devices are peripherally formed between the inner plates and the inner side of the brake housing, wherein the cooling fluid is pressed outwardly into the distributor space by the rotation of the blade-like devices, and flows back again between the outer and inner plates. Such a design of the interior of the brake housing ensures continuous circulation of the cooling fluid through and across all of the heat developing elements and corresponding heat dissipation.

In another advantageous development of the wheel hub according to the invention, the inner plates and/or the outer plates are provided with grooves on one side and/or both sides. Thereby, it is ensured that turbulences of the cooling fluid flowing between the outer and inner plates are largely avoided. The friction between the plate disks decreases, the development of heat is further decreased with not actuated brake. :

In another advantageous development of the invention, only the fixed inner plates are provided with a braking-promoting lining. It has turned out that such a design of the inner plates is also advantageous for the development of heat within the multi-disk brake. Especially, it has been determined that the outer plates drive a relatively high volume of cooling fluid or oil, respectively, if they are also provided with a braking-promoting lining, thereby high frictional forces and thus very great development of heat occurring with high velocities. In previous wheel hubs with integrated multi-disk brake, this problem did not arise, since the corresponding wheel dredges have maximum velocities of merely up to 20 km/h with 100 pm.

With higher velocities, such as with 50 km/h, already 180 rpm arise.

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In another advantageous development of the invention, a pressurized piston moves a brake plate acting on a first inner plate, wherein a spring pack is : disposed in the piston, which supports itself on an inner side of the piston on the - one hand and on a thrust plate supported on the inner hub on the other hand, "5 such that the spring pack tensions upon pressurization of the piston and releases the tension upon pressure release. Additionally, the brake plate can be connected to a brake cylinder through a tension spring. Thereby, reliable piston return is : ensured.

Further details, features and advantages of the invention result from the following description of an embodiment schematically illustrated in the figures.

There show

Figure 1 a sectional view of the wheel hub according to the invention; and

Figure 2 a top view of a sub-portion of the whee! hub according to the invention.

Figure 1 shows a sectional view of an embodiment of the wheel hub 10. Therein, the wheel hub 10 is especially suitable for an axle of a motor vehicle or truck, such as for axles of construction-site trucks and off-road vehicles or tipping trucks. A torque for a wheel (not shown) disposed on the axle is provided to a fixed inner hub 32 through an interior shaft 54. At an end opposing the drive assembly, the shatt 54 is operatively connected to a planetary gear 52. One recognizes that an outer hub 18 supports itself on the fixed inner hub 14 through taper roller bearings 56, 58, The outer hub 18 is connected to a brake housing 20 and constitutes an encapsulated housing with a space 22 for a multi-disk brake therewith. Therein, the encapsulated housing is formed in the interior such that circulation of a cooling fluid, especially oil, located therein occurs in the space 22. The multi-disk brake 12 is comprised of plural disk-shaped outer plates 16 and corresponding disk-shaped inner plates 14. Therein, the inner plates 14 constitute the fixed portion and the outer plates 16 constitute the rotating portion of the multi-disk brake 12, wherein the inner plates 14 are connected to the fixed inner hub 32 through a support

Ge 200855028 14 member 30 in rotationally fixed and axially displaceable manner. The outer plates 16 are connected to radially outward, rotating outer hubs 18 in rotationally fixed : and axially displaceable manner, wherein the outer plates 16 have radially - outward recesses 68 engaging with plural bolts 34 axially attached between outer hub 18 and brake housing 20.

Further, one recognizes that a distribution space 36 is formed for the cooling fluid circulation between an inner side of the brake housing 20 and the bolts 34. Blade- like devices are peripherally formed between the inner plates 14 and the inner side of the brake housing 20, wherein the cooling fluid is pressed outwardly into the space 22 through the distribution space 36 by rotation of the blade-like devices and flows back again between the outer and inner plates 14, 16. In the illustrated embodiment, the inner plates 14 are provided with grooves on both sides. Further, the fixed inner plates 14 have at least partially a braking-promating lining.

The multi-disk brake 12 is actuated through a pressurized piston. Therein, the pressurized piston 38 moves a brake plate 40 acting on a first inner plate 14, wherein a spring pack 42 is disposed in the piston 38. The spring pack 42 supports itself on an inner side of the piston 38 on the one hand and on a thrust plate 44 supported on the inner hub 32 on the other side. Upon pressurization of the piston 38, the spring pack 42 tensions, upon pressure release, it releases the tension. In the illustrated embodiment, the spring pack 42 is formed as a disk spring. Further, one recognizes that the brake plate 40 is connected to a brake cylinder 46 through a tension spring 48.

Additionally, the outer hub 18 has a surrounding collar 24 projecting outwards of the outer hub 18. Therein, plural openings 26 for respectively receiving a wheel bolt 28 for connecting the outer hub 18 to a rim of the wheel (not shown) are formed in the region of the collar 24. Additionally, the outer hub 18 is connected to a satellite cage 50 through plural connecting members 64 (compare also to figure 2). The outer hub 18 is sealingly connected to the brake housing 20 through plural connecting members 66. The wheel hub 10 additionally has a vent valve 60 for the space of the planetary gear 52 and the space for the multi-disk brake 12.

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Figure 2 shows a top view of a sub-portion of the wheel hub 10. One recognizes ’ the surrounding collar 24 projecting outwardly of the outer hub 18. Therein, the h collar 24 receives the wheel bolts 28 for connecting the outer hub 18 to a rim of "5 the wheel. The brake housing 20 is connected to the outer hub 18 through the connecting members 66. Further, one recognizes in schematically iliustrated manner the location of the outer plates 16 with the respectively outward recess 68 for receiving the bolts 34. Additionally, the wheel hub 10 has a bleeder valve 62 for the piston of the muiti-disk brake 12 besides the vent 60 for the planetary gear

Claims

. CL CLAIMS:

: 1. Wheel hub for an axle of a motor vehicle or truck, especially for axles of k construction-site trucks and off-road vehicles or tipping trucks, including a "5 multi-disk brake (12) consisting of plural disk-shaped outer plates (16) and corresponding disk-shaped inner plates (14) as well as an outer hub (18) and a brake housing (20) which form an encapsulated housing with a space (22) : for the multi-disk brake (12), wherein the encapsulated housing is formed in the interior such that circulation of a cooling fluid located therein occurs in the space (22), characterized in that the outer hub (18) has an at least partiaily surrounding collar (24) projecting outwardly of the outer hub (18), wherein plural openings (26) for respectively receiving a wheel bolt (28) for connecting the outer hub (18) to a rim of a wheel are formed in the region of the collar (24), and that a clearance improving the circulation of the cooling fluid is provided in the space (22) between the outer plates (16) and the outer hub (18).
2. Wheel hub according to claim 1, characterized in that the inner plates (14) constitute the fixed portion and the outer plates (16) constitute the rotating portion of the multi-disk brake (12), wherein the inner plates (14) are connected to a fixed inner hub (32) through a supporting member (30) in rotationally fixed and axially displaceable manner, and the outer plates (16) are connected to the radially outward, rotating outer hub (18) in rotationally fixed and axially displaceable manner, wherein the outer plates (16) have radially outward recesses (68) engaging with plural bolts (34) axially attached between outer hub (18) and brake housing (20).
3. Wheel hub according to claim 1 or 2, characterized in that a distribution space (36) is formed for the cooling fluid circulation between an inner side of the brake housing (20) and the bolts (34).

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4. Wheel hub according to claim 3, ) characterized in that ) blade-like devices are peripherally formed between the inner plates (14) and the inner side of the brake housing (20), wherein the cooling fluid is pressed outwardly into the space (22) through the distribution space (36) by rotation of the blade-like devices and flows back again between the outer and inner plates (14, 16).
5. Wheel hub according to any one of the preceding claims, characterized in that the inner plates (14) and/or the outer plates (16) are at least partially provided with grooves on one side and/or both sides.
6. Wheel hub according to any one of claims 2 to 5, characterized in that the fixed inner plates (14) are at least partially provided with a braking- promoting lining.
7. Wheel hub according to any one of the preceding claims, characterized in that a pressurized piston (38) moves a brake plate (40) acting on a first inner plate (14), wherein a spring pack (42) is disposed in the piston (38), which supports itself on an inner side of the piston (38) on the one hand and on a thrust plate (44) supported on the inner hub (32) on the other hand, such that the spring pack (42) tensions upon pressurization of the piston (38) and releases the tension upon pressure release. oo

’ 200 CF £07 0 / -9- PES 2 0G A HEE AA
8. Wheel hub substantially as hereinbefore described with reference to . and as illustrated in the accompanying schematic drawings. Date: 12 May 2005 John Spicer DR GERNTHOLTZ INC Patent Attorneys of Applicant(s) P O Box 8; Cape Town 8000; South Africa Union Road; Milnerton 7441: South Africa Tel: (021) 551 2650 Fax: (021) 551 2960 DrG Ref... 644714 644714P10