The invention relates to a disc wheel , in particular for commercial vehicles , with a wheel disc having a hub connection flange and an essentially cylindrical disc rim, and with a wheel rim having an outer rim shoulder, a rim well base , an inner rim shoulder and an essentially cylindrical connection region extending over an axial width between the outer rim shoulder and the rim well base , on the inner circumference of which connection region the disc rim of the wheel disc is fixed, as well as with a valve hole provided at the transition of the outer rim shoulder to the connection region for mounting a tyre inflation valve . The invention further relates to a wheel rim for a disc wheel of the kind described above .

Vehicle wheels influence in a not inconsiderable manner not only the driving behaviour of the vehicle equipped with them, but also determine to a considerable extent its fuel consumption and the achievable load capacity . Thereby, a weight of the individual wheels as low as possible has an advantageous effect on the driving behaviour and the consumption . However, weight minimization is regularly associated with a reduction in the material thickness of the wheel components , whereby stresses in the material are increased, which in turn can have a detrimental effect on load capacity .

Disc wheels of the type to which the invention relates are nowadays used mainly for commercial vehicles . They essentially consist of two steel moulded parts , namely a wheel rim and a wheel disc, which can be fixed to a wheel hub of the vehicle by means of a hub connection flange extending at least essentially radially by means of wheel bolts or nuts and is welded to a connection region on the inner circumference of the rim by means of an essentially cylindrical , circumferential disc rim.

From DE 44 32 857 C3 , a vehicle wheel for commercial vehicles is known which has a 15 ° steep-shoulder rim for tubeless tyres and a wheel disc welded to a cylindrical transition part between the rim well base and an outer rim shoulder of the rim. The cylindrical transition part is larger in diameter than the rim well base . A hump running around the circumference of the rim is provided between the rim shoulder and the transition part that can prevent the tyre from slipping off the rim shoulder into the rim well base , for example during cornering of the commercial vehicle . In the known wheel , the valve hole for receiving the tyre inflation valve is arranged in a wall of the circumferential hump closer to the inner side of the rim.

The known arrangement thus obtains the required installation space for the inflation valve by forming a hump known per se in the design of slanted shoulder rims for passenger cars , but this results in that the connection region of the wheel disc has to be reduced substantially by the height of the hump for a given tyre diameter . Thereby the space available inside the wheel is reduced, for example for the arrangement of the brake for the wheel in question . In addition, it has been shown that the arrangement of a circumferential hump is often unnecessary for commercial vehicle wheels , as the transition region adj oining the outer rim shoulder usually already offers sufficient safety against slipping of the tyre foot into the rim well ( so-called "flat hump" ) . On the other hand, the design of the rim with a circumferential hump means that increased material stresses must be expected in this region of the rim due to the additional material deformation . Accordingly, the rim thickness must be comparatively high, which means increased material requirements and correspondingly high weight .

It is the obj ect of the invention to improve a disc wheel of the type mentioned above and a respective wheel rim therefor in such a way that , on the one hand, a weight of the wheel as low as possible can be realized and, on the other hand, the strength requirements placed on the wheel rim or the disc wheel provided therewith are reliably met , and the accessibility of the tyre inflation valve mounted in the valve hole can be maintained from the outside of the wheel .

This obj ect is solved by the invention by means of a valve seat formed at the transition between the outer rim shoulder and the connection area only in the immediate vicinity of the valve hole and raised relative to the rim radius at the remaining transition area , with a valve seat flank which merges into the connection flange in which the valve hole is arranged . Compared to the mentioned state of the art , the invention thus makes it possible to dispense with a hump running around the entire rim circumference with a comparatively high side wall predetermined by the diameter of the valve hole . Rather, for the installation of the valve , a specially designed valve seat with a valve seat flank is provided only in the immediate vicinity of the valve , in which flank the valve hole is provided . Over the entire remainder of the rim circumference at the transition between the outer rim shoulder and the connection region for the wheel disc, material deformation can largely be dispensed with, whereby the material stresses in this region are limited to a minimum and accordingly a high component stability with lower material wall strengths can be achieved .

The applicant has developed the wheel according to the invention with elaborate tests and by using advanced finite element methods . It has proven to be advantageous if the arrangement is made in such a manner that the height of the valve seat above the rim radius at the remaining transition region is between 0 . 5 and 1 . 5 of the material thickness of the wheel rim at the transition between the outer rim shoulder and the connection region .

It is further advantageous if the raised valve seat extends over a circumferential angle of no more than 20 ° , preferably no more than 15 ° , more preferably no more than 12 ° , over the circumference of the wheel rim. In the particularly preferred embodiment of the invention, the valve seat thus occupies j ust 1 /30 of the circumference of the wheel rim.

The valve seat flank is preferably arranged inclined at a flank angle of 35 ° to 55 ° , preferably 40 ° to 50 ° , in particular approximately 45 ° , to the connection region . Thereby, sufficient installation space is created for the tyre inflation valve , which in most cases can actually be a standard valve with an inflation tube that has a mounting section with a fastening thread as well as a connection section angled by about 30 ° relative to the mounting section, to which connection section an inflation hose of an air supply can be connected for inflating the tyre . In order to further improve accessibility to the tyre inflation valve mounted on the raised valve seat , it is advantageous that the raised valve seat is arranged in the region of a ventilation window provided in the wheel disc . In particular , if great importance is attached to preventing the tyre foot from slipping off the rim shoulder , it can be advantageous that a hump is formed at the transition between the outer rim shoulder and the connection area , which hump runs around the entire circumference of the rim, but whose hump height is expediently no more than 1/3 of the height of the valve seat above the rim radius at the connection region . As the installation height required for the tyre inflation valve is ensured by the valve seat flank at the valve seat , which is only formed locally, the hump height can otherwise be kept low, so that the additional material requirement associated with this remains limited .

Further characteristics and advantages of the invention result from the following description of a preferred embodiment of the invention represented in the drawings . It shows :

Fig . 1 a steel disc wheel according to the invention in a perspective representation;

Fig . 1 a detail I I of the wheel rim of the wheel according to Fig . 1 in the region of the valve seat ; and

Fig . 3 the obj ect of Fig . 2 in the radial section with a tyre inflation valve mounted in the valve hole .

The drawing shows a steel disc wheel for commercial vehicles , altogether designated with 10 , which in a known manner consists essentially of a wheel disc 11 and a wheel rim 12 . The wheel disc 11 has a radially extending hub connection flange 13 with several bolt holes 14 , with which the wheel 10 can be fastened to a wheel hub of a commercial vehicle , not shown .

The wheel disc 11 further has a cylindrical disc rim 15 , with which it is welded to the inner circumference 16 of the wheel rim 12 at a connection region 17 , which is located laterally adj acent to a rim well base 18 formed in the rim 12 .

On the ( outer ) side of the connection region 17 , axially opposite the rim well base 18 , is a transition 19 to an outer rim shoulder 20 of the wheel rim 12 , on which the outer tyre foot ( not shown ) of the vehicle tyre is supported in the mounted state . A valve hole 21 for receiving a tyre inflation valve 22 for filling the tyre with air is located in the region of the transition 19 .

According to the invention, a valve seat 25 is formed at the transition 19 between the outer rim shoulder 20 and the connection region 17 only in the immediate vicinity 23 of the valve hole 21 , which valve seat is raised in relation to the rim radius at the remaining transition region 24 extending over more than 340 ° . This has a valve seat flank 26 which merges into the connection region 17 , in which flank the valve hole 21 is arranged .

The height h of the valve seat 25 above the rim radius r at the remaining transition region 24 corresponds at least approximately to the material thickness d of the wheel rim 12 at the transition 19 between the outer rim shoulder 20 and the connection region 17 . It can be seen in particular from Fig . 1 that the raised valve seat 25 extends over only a small circumferential angle a of actually no more than 12 ° over the circumference of the wheel rim 12 , and that the width of the valve seat in the axial direction of the rim is also only small . In fact , the dimensions of the valve seat 25 in the circumferential direction and in the axial direction of the rim 12 are respectively at most only slightly larger than the diameter of the tyre inflation valve 22 which is mounted in the valve hole 21 in the valve seat flank 26 .

As can best be seen in Fig . 3 , the valve seat flank is arranged inclined at a flank angle p , which can lie , for example , in the range between 35 ° and 55 ° and which, in the preferred exemplary embodiment shown, is approx . 45 ° to the connection area 17 . Fig . 1 clearly shows that the raised valve seat 25 is arranged in the region of a ventilation window 27 provided in the wheel disc 11 , whereby accessibility to the tyre inflation valve 22 is well ensured, for example , when checking the tyre air pressure , even under unfavourable positions of the wheel .

Fig . 1 further shows an optional hump 28 provided at the transition 19 between the outer rim shoulder 20 and the connection region 17 , which hump is actually formed circumferentially over the entire circumference of the rim. Unlike known wheels , however, the hump height a of the hump 28 in the wheel and the wheel rim according to the invention is no more than 1/3 of the height h of the valve seat 25 above the rim radius at the connection region 17 . This advantageous design is made possible according to the invention in that the height of the hump is not required for the appropriate positioning of the tyre inflation valve . Rather, a separate valve seat is provided only in the immediate vicinity of the valve hole , with a sufficiently high valve seat flank over only a very small circumferential region of the rim, in order to arrange the valve hole for the tyre inflation valve therein .