WO2009142574A1

WO2009142574A1 - Wheel suspension device

Info

Publication number: WO2009142574A1
Application number: PCT/SE2009/050450
Authority: WO
Inventors: Dan Pettersson
Original assignee: Scania Cv Ab
Priority date: 2008-05-23
Filing date: 2009-04-28
Publication date: 2009-11-26
Also published as: SE0801211L; SE532423C2

Abstract

The invention relates to a wheel suspension device for vehicles (4) comprising a non- rotating shaft (6) with a shaft journal (8) and, mounted on the shaft journal (8), a wheel bearing unit (10) comprising an inner running ring (12) and an outer running ring (14) which rotates relative to the inner running ring (12), the inner running ring (12) being fixed to the shaft (6), a hub (16) fitted on the outer running ring (14), and a protective ring (24), which serves as thermal radiation shielding, comprises at least one aperture (26) and at least one protruding means (28, 30) in the form of an air deflector, is arranged fixed relative to the outer running ring (14) of the wheel bearing unit (10), extends away from the wheel bearing unit (10) in a space between the shaft (6) and the hub (16) and is adapted to rotating together with the hub (16) and the outer running ring (14) of the wheel bearing unit (10) when the vehicle (4) is in motion, which aperture (26) and protruding means (28, 30) are arranged and angled in such a way that a cooling and particle-diverting air flow (B) away from the inside (32) of the protective ring (24) is created through the aperture (26) and thereafter towards the inner surface (36) of the hub (16) situated on the outside (34) of the protective ring (24), and thereafter also away from the wheel bearing unit (10), when the vehicle (4) is travelling forwards.

Description

WHEEL SUSPENSION DEVICE

Technical field

The present invention relates to a wheel suspension device for vehicles according to the preamble of claim 1.

Background

A wheel suspension for vehicles comprises a non-rotating shaft with a shaft journal and, mounted on the shaft journal, a wheel bearing unit on which a hub is fitted. A wheel rim with tyre and a brake disc may be fitted to the hub so that the wheel rim, the tyre and the brake disc rotate about the shaft journal when the vehicle is in motion. Braking the vehicle is effected by brake shoes being pressed against the sides of the brake disc, thereby retarding the tyre's rotation and hence also the vehicle. Particularly on slippery roads, it is desirable that the vehicle wheels should not lock during braking, as this would lead to a longer braking distance and might at the same time deprive the driver of the possibility of steering the vehicle past any obstacles on the road.

To prevent their wheels from locking upon powerful braking, vehicles are often provided with ABS brake systems which comprise ABS sensors at each wheel, by means of which the force applied to the vehicle's brakes can be controlled and limited. Repeated braking within a short period of time will result in powerful heating of the brake disc, which will therefore begin to generate conduction heat and radiation heat. This leads to problems on vehicles with disc brakes, since the ABS sensor, which is usually situated close to a brake disc, will cease to function when subjected to high temperatures, leading to the ABS brake system being out of action, with the result that the brakes may lock upon powerful braking. ABS sensors are therefore fitted in such a way that they are as far as possible exposed to the cooling influence of the air flow caused by vehicle movement, but in such a way that they are also protected from, for example, gravel particles thrown up by the vehicle in motion. For this reason, the ABS sensors are usually situated close to the wheel bearings, which are nevertheless exposed to dirt, e.g. in the form of gravel or oil, and are therefore provided with bearing seals of an elastic kind or in the form of a protective disc of rigid material arranged on the outside of the bearing.

EP 1 239 173 Bl refers to a seal device for rolling bearings, in which a disc which rotates with the outer running ring of the bearing is arranged on the side of the bearing which is subject to a higher pressure. The disc is provided with a number of protruding blades which cause an air flow which reduces the pressure at the bearing surface, thereby equalising pressure differences between the sides of the bearing and hence preventing leakage from the high-pressure side of the bearing to the low-pressure side of the bearing, thereby also preventing grease from the bearing from leaking out on the low-pressure side of the bearing.

However, a bearing seal device of the abovementioned kind provides no protection from radiant heat.

Brief description of the invention

The problem that an ABS sensor is subject to heat and an adjacent wheel bearing is subject to dirt is solved according to the invention by a wheel suspension device according to the characterising part of claim 1.

A wheel suspension device according to claim 1 which comprises the characteristics that a protective ring which serves as thermal radiation shielding and comprises at least one aperture and at least one protruding means in the form of an air deflector is arranged in a space between a shaft and a hub, which protective ring is adapted to rotating together with the hub when the vehicle is in motion and to creating a cooling and particle-deflecting air flow towards the hub situated on the outside of the protective ring when the vehicle is travelling forwards, affords the advantage that the ABS sensor does not become overheated, with the result that locking of the braked wheel is prevented, dirt is prevented from reaching, being deposited on and hence even making its way into the wheel bearing or between wheel bearing and shaft journal and hub respectively, and the service life of the wheel bearing is thereby lengthened. Brief description of the drawings

The invention is explained in more detail below with reference to the attached drawings, in which:

Figure 1 depicts schematically a partly cutaway view of a wheel suspension device with protective ring according to a first embodiment of the invention,

Figure 2 depicts schematically a partly cutaway view of a wheel suspension device with protective ring according to Figure 1 in a different projection,

Figure 3 depicts schematically a view of a protective ring according to a first embodiment of the invention, and

Figure 4 depicts schematically a section of part of a wheel suspension device comprising a protective ring according to the invention.

Description of preferred embodiments

Similar items in the various drawings are designated by the same reference notations.

Figure 1 depicts schematically a partly cutaway view of a wheel suspension device 2 for a vehicle 4 according to a first embodiment of the invention, which wheel suspension device 2 comprises a non-rotating shaft 6 with a shaft journal 8 and, mounted on the shaft journal

8, a wheel bearing unit 10 comprising an inner running ring 12 fastened to the shaft journal 8, and an outer running ring 14 rotating relative to the shaft journal 8. The wheel bearing unit 10 is preferably of rolling bearing type, i.e. of ball bearing type or roller bearing type. The wheel suspension device 2 further comprises a hub 16 which is fastened to the outer running ring 14 and to which a wheel rim (not depicted) is adapted to being able to be fitted by the fact that the hub has recesses 18 for fastening elements in the form of screws by which the wheel rim can be fastened to the hub 16. The hub 16 further comprises recesses 20 for fastening elements in the form of screws by which a brake disc 22 can be fitted to the hub 16. A protective ring 24 is preferably fastened to the outer running ring 14 of the wheel bearing unit 10 by being pressed onto the outside of the outer running ring 14, but may alternatively be fastened to a portion of the hub 16 which is situated adjacent to the wheel bearing unit 10, i.e. a short distance away from the brake disc 22. The protective ring 24 comprises a number of apertures 26 and a number of protruding means 28, 30, which means 28, 30 by being configured as air deflectors create an air flow through the apertures 26 in the protective ring 24 when the latter rotates about an axis through the centre of the ring. As mentioned above, the protective ring 24 is adapted to rotating together with the hub 16 and the outer running ring 14 of the wheel bearing unit 10 when the vehicle is in motion, thereby creating an airflow through the apertures 26 in the protective ring 24. The apertures 26 and the protruding means 28, 30 are arranged and angled in such a way that the air flow created moves away from the inside of the protective ring 24, through the apertures 26 and thereafter towards the hub 16 situated on the outside 34 of the protective ring 24 when the vehicle 4 is travelling forwards.

Figure 2 depicts schematically a partly cutaway view of a wheel suspension device 2 with protective ring 24 according to Figure 1 in a different projection in which the shaft 6 with a shaft journal 8, the wheel bearing unit 10 mounted on the shaft journal 8, and the hub 16 fitted thereon, are also visible. The drawing also shows the protective ring 24 arranged to extend along the inner surface 36 of, and at a distance from, the hub 16 and thereby constituting a shield between the hub 16 and an ABS sensor 38 fitted fixed to the shaft 6, whereby the ABS sensor 38 is partly shielded mechanically from the thermal radiation emitted by the hub 16 due to the hub 16 being warmed by the brake disc 22 when the latter has been warmed by a number of brakings over a short time, e.g. when the vehicle is travelling on a long downgrade. In addition to the mechanical shielding, there is also cooling of the hub 16 by the fact that the air flow created by the configuration described above of the protective ring 24 is directed towards, and cools, the inner surface 36 of the hub 16. These two mechanisms afford the advantage that the ABS sensor 38 does not become overheated, that locking of the braked wheel on the hub 16 is thereby prevented and that the wheel bearing unit 10 is also acted upon by less heat than would be the case without a protective ring 24. A further advantage is that the air flow formed round the protective ring also prevents deposition on the inner surface 36 of the hub 16 of particles and liquid which might in time make their way into the wheel bearing unit 10 or in between the wheel bearing unit 10 and the hub 16 and the shaft journal 8 respectively, as well as settling on the ABS sensor 38.

Figure 3 depicts schematically a view of a protective ring 24 according to a first embodiment of the invention, which protective ring 24 comprises a number of apertures 26 and a number of protruding means 28, 30, which means 28, 30 by being configured as air deflectors create an air flow through the apertures 26 in the protective ring 24 when the latter rotates about an axis A through the centre of the protective ring 24. As illustrated in the drawing, the protruding means 28, 30 comprise two different kinds of air deflector, the protruding means 28 arranged on the inside 32 of the protective ring 24 in the form of air- deflecting scoops intended to direct an air flow in towards the apertures 26, and the protruding means 30 arranged on the outside 34 of the protective ring 24 in the form of air- deflecting wings intended to guide the air flowing from the apertures 26 away from the wheel bearing unit but at the same time towards the inner surface of the hub when the vehicle is travelling forwards, taking the inside, inner surface and outside respectively as seen in a radial direction relative to the axis of rotation A. This air flow created by the protective ring 24 when the vehicle is travelling forwards cools the inner surface of the hub, with the result that the ABS sensor is not subject to high temperatures in situations where the brake disc has warmed the hub. Said airflow also prevents dirt and liquid from being deposited on the inner surface of the hub. The configuration of the apertures 26 and the size, orientation, number, thickness and shape of the various protruding means 28, 30 may be adapted by one skilled in the art to various wheel suspensions and their configurations in order to achieve optimum air flow through the apertures 26 and optimum directions of the air flows into and out from the apertures 26.

The protective ring 24 may be made of any desired material which can maintain its shape despite being acted upon by dirt, oil, centrifugal force and high and low temperatures, i.e. a material which tolerates the environment to which a vehicle hub is subject in both summer and winter. Suitable materials comprise inter alia metals, plastics, rigid rubber materials, ceramics. The protective ring 24 may be made inter alia by pressing or casting or by machining from a blank.

Figure 4 depicts schematically a section of part of a wheel suspension device 2 comprising a protective ring 24 according to the invention. It also shows a hub 16, an outer running ring 14 of a wheel bearing unit 10, and a brake disc 22, which are adapted to rotating relative to an ABS sensor 38 as described above which is fixed relative to a shaft (not depicted). The drawing shows how the protective ring 24, which has an inside 32 and an outside 34, constitutes a mechanical shield against radiant heat between the ABS sensor 38 and the inner surface 36 of the hub 16. In addition, as described above, the protective ring 24 gives rise, when the vehicle is in motion, to air flows B through the apertures 26 in the protective ring 24, which air flows B are directed away from the wheel bearing unit 10 but at the same time towards the inner surface 36 of the hub 16 when the vehicle is travelling forwards, taking the inside, inner surface and outside respectively as seen in a radial direction relative to an axis of rotation. This air flow B created by the protective ring 24 when the vehicle is travelling forwards cools the inner surface 36 of the hub 16, with the result that the ABS sensor 38 is not subject to high temperatures in situations where the brake disc 22 has warmed the hub 16. Said air flow B also prevents dirt and liquid from being deposited and settling on the inner surface 36 of the hub 16, thereby preventing these notional deposits from being able to gradually impair the function of the ABS sensor 38 and the wheel bearing unit 10. As mentioned above, the air flows B through the apertures 26 in the protective ring also cool the inner surface 36 of the hub 16, thereby reducing the thermal radiation which reaches the ABS sensor 38 from the hub 16.

Claims

1. A wheel suspension device for vehicles (4) comprising a non-rotating shaft (6) with a shaft journal (8) and, mounted on the shaft journal (8), a wheel bearing unit (10) comprising an inner running ring (12) and an outer running ring (14) which rotates relative to the inner running ring (12), the inner running ring (12) being fixed to the shaft (6) and a hub (16) being fitted on the outer running ring (14), characterised in that a protective ring (24), which serves as thermal radiation shielding and comprises at least one aperture (26) and at least one protruding means (28, 30) in the form of an air deflector, is arranged fixed relative to the outer running ring (14) of the wheel bearing unit (10), extends away from the wheel bearing unit (10) in a space between the shaft (6) and the hub (16) and is adapted to rotating together with the hub (16) and the outer running ring (14) of the wheel bearing unit (10) when the vehicle (4) is in motion, the aperture (26) and the protruding means (28, 30) are arranged and angled in such a way that a cooling and particle-diverting air flow (B) away from the inside (32) of the protective ring (24) is created through the aperture (26) and thereafter towards the inner surface (36) of the hub (16) situated on the outside (34) of the protective ring (24), and thereafter also away from the wheel bearing unit (10), when the vehicle (4) is travelling forwards.

2. A wheel suspension device according to claim 1, characterised in that the protective ring (24) is fastened to the outer running ring (14) of the wheel bearing unit (10) by being pressed onto the outside of the outer running ring (14).

3. A wheel suspension device according to claim 1 , characterised in that the protective ring (24) is fastened to a portion of the hub (16) which is situated adjacent to the wheel bearing unit (10).

4. A wheel suspension device according to any one of claims 1-3, characterised in that the protective ring (24) is arranged to extend along the inner surface (36) of, and at a distance from, the hub (16).

5. A wheel suspension device according to any one of claims 1-3, characterised in that a wheel rim and a brake disc (22) are adapted to being able to be fitted on the hub (16), and an ABS sensor (38) is adapted to being able to be fitted fixed relative to the shaft (6).

6. A wheel suspension device according to claim 5, characterised in that the hub (16) comprises recesses (18) for fastening elements by which the wheel rim can be fixed to the hub (16), and further comprises recesses (20) for fastening elements by which a brake disc (22) can be fitted to the hub (16).

7. A wheel suspension device according to either of claims 5-6, characterised in that the protective ring (24) is arranged to extend along the inner surface (36) of, and at a distance from, the hub (16) and thus constitutes a shield between the hub (16) and the ABS sensor (38) whereby the ABS sensor (38) is partly shielded mechanically from thermal radiation emitted by the hub (16).

8. A wheel suspension device according to any one of claims 1-7, characterised in that the protruding means (28, 30) comprise two different kinds of air deflector, the protruding means (28) arranged on the inside (32) of the protective ring (24) in the form of air-deflecting scoops intended to guide an air flow in towards said at least one aperture (26), and the protruding means arranged on the outside (34) of the protective ring (24) in the form of air-deflecting wings intended to guide the air flow (B) from the apertures (26) away from the wheel bearing unit (10) and at the same time towards the inner surface (36) of the hub (16) when the vehicle is travelling forwards.

9. A wheel suspension device according to any one of claims 1-8, characterised in that the protective ring (24) is made of a material which can maintain its shape despite being acted upon by dirt, oil, centrifugal force and high and low temperatures, which material is selected from among metals, plastics, rigid rubber materials, ceramics.