Patent Application
20220334019
The present invention relates to a leak test machine for a vehicle rim, such as a rim of a wheel of a light or heavy vehicle, for example of a car or truck or agricultural vehicle.
Leak test machines are known in the art. This type of machine is used to identify very small leaks in the rim.
Leaks are due, for example, to porosity in the case of cast rims (obtained by gravity, low pressure or die casting), or to welding defects in steel rims, or to poor adhesion of the layers forming a wheel made of composite material (carbon fiber or other).
To carry out the test, sealing the rim between two gaskets, a lower one and an upper one, is known, so as to obtain a so-called inner chamber. A so-called bell (or outer chamber) then closes the entire rim, thus simulating the tire. The machine then proceeds to pressurize the outer chamber, with air or with a gas mixture including a tracer gas. In the inner chamber, the increase of pressure or the increase of tracer gas concentration is measured. Thereby, with special algorithms, it is quickly determined if there is a seeping (leak) between the outer chamber and the inner chamber.
It is important that this type of machines is capable of randomly testing rims with the widest variety of different sizes and styles.
Over the years, sizes and styles have transformed the rim market. Designers have created increasingly larger rims and more and more sophisticated styles. During these evolutions, protruding styles were defined (hub protruding with respect to the upper edge) as well as styles modifying the edge itself, to such an extent that the spoke of the rim reaches over the edge. It is even possible that some sort of small grooves are obtained in the edge, i.e., partial interruptions of the edge itself.
As a result, when the upper gasket rests on the outer edge of the rim, the test machines of the background art fail, for example, because of the edge below the hub plane or because of the discontinuities encountered on the edge do not allow an adequate sealing.
The problem of the hub protruding from the rim edge has been solved in the art by virtue of the presence of a conical upper gasket. Inconveniently, when the rim is not well aligned, the conical-shaped upper gasket causes a non-uniformity of the load on the periphery of the rim edge, with a consequent poor sealing on the edge. In these cases, the machine generates so-called “false rejects” (i.e., rims which have no leaks, but which the machine defines as rejects). For these reasons, in which the use of a conical gasket is required, it is necessary to maintain a very low cone angle (narrow angles of inclination), to limit the generation of false rejects as much as possible.
However, the issue relating to the presence of rims with interrupted edges has not yet been solved. In fact, although a wider angle of the cone of the upper gasket may allow an improved sealing, this would lead to an increased generation of false rejects in the rims with a protruding hub.
For the above reasons, to date, suitably shaped annular elements in rubber are provided, which, once applied to the rim edge, give continuity to the rim edge, thus allowing tests to be carried out. Unfortunately, for each size and style of rim it is necessary to have a customized annular element. Furthermore, in addition, it is necessary to insert and remove the annular element each time the test is carried out.
Therefore, the need to propose a leak test machine for vehicle rim capable of overcoming the drawbacks of the leak test machines of the background art is felt. In particular, it is one of the objects of the present invention to provide a leak test machine for vehicle rim which is capable of testing multiple varieties of vehicle rims in a quick, reliable manner and without complicated procedures that slow down the testing operations.
Such an object is achieved by a leak test machine for vehicle rim in accordance with the appended independent claim. The dependent claims describe preferred or advantageous embodiments of the leak test machine for vehicle rim.
The features and advantages of the leak test machine for vehicle rim in accordance with the invention will however become apparent from the following description of preferred embodiments thereof, given by way of non-limiting indication, with reference to the accompanying drawings, in which
With reference to the aforesaid Figures, reference numeral 1 generally indicates a leak test machine 1 for vehicle rim 2 (also known as wheel rim), for example a rim of a motorcycle, a car or large motor vehicle, such as a truck or the like.
The leak test machine 1 comprises a base 3, which supports a lower sealing element 31, for example, an annular gasket, suitable to receive a first edge 21 of the rim 2. Preferably, the first edge 21 of the rim 2 is the inner edge of the rim, i.e., the edge intended to face the vehicle body when the rim is mounted on the vehicle.
The first edge 21 and the outer edge 22 are therefore the edges of the rim on which the tire is fitted.
The base 3 is supported by a support plane, for example, by a floor, by means of a suitable support frame of the machine. Preferably, therefore, the machine comprises a support frame, which, on one side, rests on the floor and, on the other, is connected to the base 3.
The leak test machine 1 comprises a closing element 4, preferably in the shape of a cylindrical bell or parallelepiped, which is translatable along a translation direction X, preferably a vertical translation direction (i.e., perpendicular to the support plane of the machine), so as to take an open configuration in which the closing element 4 is not engaged with the base 3, and a closed configuration, in which the closing element 4 sealingly engages the base 3, so as to define a outer chamber 41 which completely surrounds the rim 2. In other words, in the open configuration, it is possible to insert the rim 2 on the first sealing element 31, for example, by an operator or a rim handling system; in the closed configuration, on the other hand, the closing element sealingly closes the outer chamber 41, around the rim 2.
The leak test machine 1 further comprises an upper sealing group 5 contained in the outer chamber 41 and translatable along the translation direction X to sealingly engage the rim 2 on an outer edge 22 of the rim 2 opposite to the first edge 21, so as to define an inner chamber 20 delimited by the upper sealing group 5, the lower sealing element 31 and the channel walls 23 of the rim 2. Therefore, when the upper sealing group sealingly engages the rim 2, the inner chamber 20 is defined, which results arranged inside the outer chamber 41, but sealed and not communicating with the outer chamber 41.
The leak test machine 1 further comprises a sealing group translation device 6, operatively connected to the upper sealing group 5 to move the sealing group along the translation direction X.
According to a preferred embodiment, the closing element 4 comprises a closing element sidewall 42, 42′ suitable to sealingly engage the base 3. In this variant, the sealing group translation device 6 comprises a sealing group support element 61 slidably sealingly engaged with the closing element sidewall 42, 42′. Thereby, the outer chamber 41 is defined not only by the closing element 4, but, mostly, also by the sealing group translation device 6.
The upper sealing group 5 is supported in an articulated manner by the sealing group translation device 6, so as to allow at least one rotation of the upper sealing group 5 around an axis incident to the translation direction X. This allows to better adapt the upper sealing group 5 to the outer edge plane 22 of the rim.
According to a preferred embodiment, the upper sealing group 5 is supported in an articulated manner by the sealing group translation device 6 in an idle manner, i.e., in a passive and non-actuated manner.
Furthermore, preferably, the upper sealing group 5 is supported in a spaced manner by the sealing group translation device 6. This allows a movement space to be left between the sealing group translation device 6 and the upper sealing group 5.
According to an advantageous embodiment, the upper sealing group 5 is connected to the sealing group translation device 6 by means of a ball joint 71.
Preferably, the upper sealing group 5 comprises a support portion 52 and a sealing portion 51 being conical or truncated cone-shaped.
Preferably, in the conical or truncated cone shape, the sealing portion 51 comprises a sealing portion side wall 510 inclined with respect to a horizontal direction Y perpendicular to the translation direction X by an angle of inclination α at least equal to 20°. In accordance with advantageous embodiments, the angle of inclination α is chosen between 20° and 40°, including extremes, for example equal to about 40°. Such an angle of inclination α is measured as the acute angle between the horizontal direction Y and the inner surface 510′ of the sealing portion sidewall 510 intended to come into contact with the outer edge 22 of the rim.
According to a preferred embodiment, the support portion 52 is truncated cone-shaped, comprising a sidewall of the support portion 520 inclined with respect to the horizontal direction Y, preferably with the same angles already indicated for the sealing portion 51.
Preferably, the sealing portion 51 is joined to the support portion 52 along the sidewall of the support portion 520.
Preferably, a junction element 7 connects the upper sealing group 5 to the sealing group translation device 6. In this variant, the support portion 52 comprises a support portion base wall 521 and the junction element 7 is fixed on one side integrally with the support portion 521 and, on the opposite side, comprises the ball joint 71 connected to the sealing group translation device 6.
Preferably, the leak test machine comprises a device for detecting a tracer gas, for example helium, inside the inner chamber 20, to detect any defects in the rim 2.
Preferably, the lower sealing element 31 and/or the sealing portion 51 are made of a polymeric material, preferably rubber or a silicone material.
To carry out the test on the rim 2 inserted in the leak test machine 1 according to the present invention, the closing element 4 is therefore opened, by translating it, by means of first translation means, along the translation direction X (not shown). This allows an access to insert the rim 2 resting on the lower sealing element 31 (for example, an annular gasket) along the first edge 21. The closing element 4 is then translated until it is sealingly engaged against the base 3. In this case, a further sealing element 8 (for example, a gasket) is preferably provided on the base 3 or on the closing element 4.
Subsequently, or in conjunction with the closure of the closing element 4, the sealing group translation device 6 is moved along the translation direction X until the upper sealing group 5 is sealingly engaged with the outer edge 22 of the rim. During this step, any inclination or misalignment of the rim with the upper sealing group 5 is compensated by the mobility of the upper sealing group 5 itself with respect to the sealing group translation device 6 and to the base 3 as well as with respect to the closing element 4.
At this point, the inner chamber 20 and the outer chamber 41 are created and not communicating with each other.
A pressurized gas mixture is then injected into the outer chamber 41. Such a gas mixture contains a tracer gas, for example helium.
After the outer chamber 41 has been pressurized, the pressure increase in the inner chamber 20 is detected, by means of a pressure detection device, or (or concomitantly) the tracer gas concentration over time in the inner chamber 20 is detected.
If the pressure of the inner chamber or the concentration of tracer gas exceeds a certain threshold in a certain time interval, the presence of a seeping, and, therefore, a possible defect of the rim, is thus detected.
Innovatively, the leak test machine according to the present invention allows to solve the drawbacks related to the background art. In particular, the leak test machine according to the present invention allows multiple types of rims to be tested in a quick and reliable manner, reducing the number of false rejects.
In fact, by virtue of the presence of the rotatable, or, even better, pivoting or floating upper sealing group 6, it is possible to compensate for any misalignments between the axis of the rim and the axis of the truncated cone of the upper sealing group 5. By virtue of this, a possible non-uniformity in the application of the load on the rim is avoided, which happens, instead, in machines of the background art in which the upper sealing group is fixed.
Furthermore, in a synergic way with the presence of the rotatable (or, even better, pivoting or floating) upper sealing group 5, it is possible to obtain the sealing portion 51 with a sealing portion side wall 510 inclined, with respect to the horizontal direction Y, by a rather wide angle of inclination α (at least equal to 20°, or even wider, for example equal to 40°). The increased angle of inclination allows to test rims with very protruding hubs and discontinuous edges, since it allows the sealing portion 510 to work on an edge periphery which is not interrupted by spokes nor discontinuities. Furthermore, the increased angle of inclination, made possible by the presence of a rotatable or floating upper sealing group 5, also allows to reduce the load on the sealing portion, increasing the duration thereof over time. Furthermore, being capable of reducing the load on the rim, it is possible to use softer materials for making the sealing portion 51 and/or the sealing element 31, which allow to better adapt to the irregularities of the rim edges. Preferably, the lower sealing element 31 and/or the sealing portion 51 are made of a polymeric material, preferably rubber or a silicone material, with shore hardness A between 45 and 85, and even more preferably between 50 and 80, for example, about 50.
Those skilled in the art, in order to meet specific needs, may modify the embodiments of the leak test machine for vehicle rim, or replace elements with others which are functionally equivalent.
Such variants are also included in the scope of protection as defined by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102019000014244 | Aug 2019 | IT | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2020/057091 | 7/28/2020 | WO |
