Metal valve of the clamp-in type for inflating tyres associable with a tpms transducer

The present invention relates to a valve section for inflating tire tires, in particular wheels for vehicles, the term "vehicles" being used to refer to motor vehicles, vans, trucks, motorcycles, or generally tire-carrying means.

In particular, the invention relates to a controlled tightening of a clamp type metal valve intended for use in the context of TPMS technology (tire pressure monitoring system) in which electronic sensors detect and transmit certain tire operating parameters, in particular pressure, but also e.g. , temperatures are mounted directly on the valve itself, and the valve is attached to the wheel by means of a hole made in the rim.

[0003] Clamp-type metal valves typically consist of a shaped head, usually cylindrical or hemispherical or polygonal, which is associated with a transducer incorporating electronic sensors, and an elongated rod (or rod) permitting pumping / discharging action of the tire and mounting of said valve to the wheel rim by means of specific screw fastening means.

[0004] Said screw fastening means typically consist of a threaded nut made on a portion of the valve stem projecting out of the rim. [0005] Functionally, the valve and the transducer are first connected to each other in the transducer valve assembly by means of a perforated mounting screw. Said bolt is usually provided with a square head and is adapted to axially block the valve head in a special complementary seat positioned in the transducer.

[0006] In a further step, the valve-transducer assembly is positioned on the rim so that the valve protrudes out of the rim and the transducer is placed inside the tire, and rests on the inner rim flange so that it is tangent to said rim and thus reduces the possibility of contact with the tire during assembly and disassembly operations.

[0007] The valve-to-transducer assembly is screwed onto the rim with a nut that, by screwing on the valve stem, drives the transducer into contact with the valve head and thus with the head itself, with the gasket placed on the inner edge of the rim.

[0008] These valve-transducer assemblies have several limitations and drawbacks.

[0009] Metal clamp type valves are subjected to possible damage during the final tightening of the nut by means of which the valve-to-transducer assembly is attached to the rim: incorrect dosing of the clamping force poses a risk of axial rotation of the entire valve-transducer assembly, thus extending the transducer from its socket in relation to its correct tangent position to the rim. Even a minimal rotation of the transmitter carries the risk of damaging it, for example when replacing a tire.

Furthermore, the occurring centrifugal forces and vibrations of the vehicle while driving can increase the risk of the transducer becoming unscrewed from the valve if the two elements are not securely attached to each other, or may even cause the nut to loosen.

Furthermore, the assembly operations, first of the valve on the transducer, then the valve-to-transducer assembly on the rim, can become disadvantageously long and complicated, considering the number of parts present and the fact that they often have to be operated in limited rim spaces, and not always guarantee the safest, most appropriate placement of components.

[0012] Patent application EP 12 77 601 A2 discloses a valve-transducer assembly that solves these problems, wherein the transducer and valve body are pre-assembled by means of a mounting screw, the square head of which engages / connects to a socket having the same shape, belonging to the transducer, and the body of which is screwed to the valve body.

The tightening of the transducer on the valve body is completed during the initial valve tightening phase on the rim, which is achieved by means of a special nut that can be screwed onto the valve spindle.

The inside of said nut is provided with a protruding annular element adapted to be broken when screwing the nut onto the valve spindle, only after reaching a specific tightening torque corresponding to the force necessary to properly tighten the transducer on the valve head.

[0015] After the protruding annular element has been broken, the nut is continued to be tightened, with higher torque values, which serves to secure the valve-transducer assembly thus obtained on the rim.

[0016] The solution of providing the ring member with a controlled rupture inside the nut signifying that a certain tightening torque has been achieved, although it solves the aforementioned problems, appears to be complicated to manufacture.

In practice, it is not straightforward to obtain this annular element by means of a tool acting directly on the interior of the cap, and it is even more difficult to guarantee that said element has a tensile strength exactly as it is actually required.

[0018] The steps to check and verify this element within the cap are difficult due to the limited size of the available working space and, therefore, limited access to the working and measuring zone.

[0019] Also in the assembly phase, any accidental or inaccurate breakage of this element may not be readily apparent to the operator.

[0020] In the case where said valves are made of aluminum and have to undergo surface treatment to prevent environmental corrosion, the application of a protective layer to the inside of the cap may be made even more difficult by the presence of said annular element that, after fracture, leaves the exposed portion unprocessed metal.

[0021] The design disadvantage and reduced reliability of the solution proposed by the aforementioned patent application is therefore evident.

[0022] The object of the present invention is therefore to provide a valve whose entire assembly system with transducer and rim is safe and accurate, but also simple and fast, and able to always guarantee perfect stability, primarily between the valve and the transducer during their final connection, and then with the assembly of the assembly on the rim.

[0023] These objects are achieved by a metal valve of the clamping type for tire inflation connected stably to the TPMS transducer by means of a locking screw and adapted to be mounted by means of a fastening system comprising a nut adapted to be screwed onto a thread positioned on the spindle of said valve on the rim of the wheel, wherein said fixing arrangement comprises an element that irreversibly disappears when a predetermined tightening torque is achieved for said locking nut, characterized in that said member which is irreversibly disappears is associated with the mandrel of said valve.

[0024] According to possible embodiments of the invention, said element resolves irreversibly after breakage or deformation.

[0025] Preferably, the broken part of said element is adapted to cooperate with said nut and said spindle of said valve to act as a barrier against entry of corrosive agents into said nut.

[0026] According to a first embodiment of the invention, said element has an annular or flaky shape.

[0027] According to a further embodiment of the invention, said element is made directly of the same material as the spindle of said valve, or it may be made of a material placed thereon.

In a particularly preferred embodiment of the invention, said element is obtained by modifying a thread provided on the spindle of said valve in such a way that part of said thread has a different pitch or modified tolerance of engagement with said nut so as to define zones with different torques. .

[0029] According to preferred embodiments of the invention, said element, with respect to various predetermined torques, may have different thicknesses or shapes, or may be made of different materials, and may also be marked with different colors.

[0030] Furthermore, the part of the element that remains visible on the valve stem after its fracture or deformation is adapted to act as an indicator, outside the tire, in the presence of a transducer within it.

[0031] The advantages of the invention are obvious, above all because of the simple design of the valve: creating a break directly on the valve body can be done very easily in the manufacture of the valve itself, and it is always possible to work with precision in size selection and dimensional control, thus guaranteeing the proper selection of resistance to the fracture you want to give to the element. [0032] A variant in which said element is manufactured from a material used for the valve body is very advantageous: in this case there are different ways of personalizing and differentiating the valve, due to the fact that the element can be made of the most suitable material and can have a geometry and thickness that are more suited to the required performance.

[0033] Even more preferably, if the element is mounted, the integrity of the treatment of any surface on the valve is ensured: breaking the element does not compromise the continuity of the protective surface, but rather the broken part of the element closes the space between the nut and the thread, thus preventing possible entry water or other potentially corrosive agents.

[0034] For purposes of quickly determining the most suitable valve, i.e. a valve provided with the most suitable susceptible member, said member may have a specific color associated with its resistance to torque. The operator will thus be able to identify the valve most suitable for use more quickly.

[0035] The occurrence of an element on the outer surface of the valve stem, whether or not the said member is obtained from a mandrel or mounted thereon, also acts as an indicator visible outside the rim in the presence of a TPMS transducer within the tire.

Generally speaking, there is also an advantage in the form of a high degree of safety which imparts to the wheel through proper mounting of the valve-transducer assembly: in this situation too, the risk of disconnecting the transducer from the valve while the vehicle is moving is eliminated.

[0037] These and other advantages will become more apparent from the following description of preferred embodiments of the invention, given by way of non-limiting example, by means of the figures, wherein:

Figs. 1 and 2 are perspective and top view views of a valve-transducer assembly for wheel-mounted TPMS systems, respectively;

Figs. 3-5 are a longitudinal section of a metal type of a clamp type associated with a transducer and attached to a rim according to possible embodiments of the invention;

Fig. 6 shows a longitudinal section of the detail of Fig. 4 during the valve assembly phase

Figs. 7a and 7b show a longitudinal section of a detail of the valve in the embodiment shown in Fig. 5 in two operational assembly phases.

[0038] With reference to the figures, a metal valve of the clamping type 1 for inflating tires 2 is shown, adapted for stable association with transducer 3 using TPMS technology.

[0039] With particular reference to Figs. 1 and 2, a motor vehicle wheel rim 6 is shown, on which said valve 1 and said transducer 3 are mounted, assembled together to form a valve-transducer assembly.

With reference to the illustrated cross-section, the position of each valve component 10 of the valve-to-transducer assembly 10 is obvious, particularly with respect to the rim 6. The transducer 3 is positioned tangentially to the rim 6 inside the air chamber 9 limited by the respective tire 2, the valve 1 protrudes out of the rim 6 and is stably fixed to it by means of the lock nut 5.

[0042] With respect to the cross-sections shown in Figs. 3-5, the possible embodiments of the valve 1 according to the invention are described in more detail, wherein the valve 1 comprises a rod 8 and a head 11.

[0043] Between the inner edge of the rim 6 and the head portion 11 of the valve 1, a seal 12 is placed in contact with the rim 12. The seal 12 can be either elastic (O-Ring) or metal (Grommet).

[0044] Alternatively, the valve head may be in direct contact with the rim, without seals.

[0045] Between the outer edge of the rim 6 and the locking nut 5, a washer 13 made of metal or plastic is usually placed.

[0046] With reference to all the attached figures, only by way of example, a particular type of pinch valve 1 is selected, provided with an axially perforated hemispherical head 11. Other valve variants 1 may include cylindrical heads 11, or so-called "hammer heads", wherein the sensor-to-sensor connection is achieved on two suitably shaped, symmetrical support surfaces, always according to the claims and achieving the same advantages.

[0047] For connection to the transducer 3, the valve head 11 has a special seat 14 formed in the transducer 3.

In order to stably connect the two components, through both valve 1 and transducer 3, a perforated screw 4 passes whose head 15 has a square or polygonal cross-section, or can have other shapes for corresponding connections.

[0049] The shaft of the screw 4 is screwed onto the thread inside the valve body 1, whereas the square head 15 enters a suitably shaped housing in the transducer 3 so that the valve 1 can rotate with respect to the screw 4, which in turn remains stationary with respect to the transducer 3.

[0050] This mutual rotation between the valve 1 and the screw 4 is achieved during the assembling phase of the valve-to-transducer assembly on the rim by means of a nut 5 which rests on the impactor element 7 on the valve stem 8.

With reference to the section shown in Fig. 3, said element 7 has an annular shape and is made directly of the same material as the valve stem 8, protruding perpendicularly therefrom. In this embodiment, said annular element 7 gives way irreversibly after fracture: upon reaching the maximum tightening torque for the screw 4 connecting the valve 1 to the transducer 3, said element 7 breaks.

[0052] The thickness and shape of said element 7 determine its strength: the thin annular element 7 breaks easily and can be used for valves that do not require high torques when tightened to connect to the transducer. On the other hand, if the ring member 7 is thicker, it will break with greater difficulty: in this case, the valve will be stably attached to its transducer only when high torque occurs during tightening.

[0053] The cross-section in Fig. 4 shows a possible alternative embodiment of the valve 1 shown in Fig. 3. In this case, the annular element 7 gives way irreversibly after the deformation: its cross-section (e.g. trapezoidal) is shaped such that after reaching the required moment When rotating, the nut 5 irreversibly deforms said element 7 by bending it towards the spindle 8 of the valve 1, and then continues to screw (Fig. 6).

[0054] In a preferred embodiment, said element 7 can be obtained by modifying a thread 18 placed on the shaft 8 of the valve 1 onto which the nut 5 is screwed.

[0055] By dimensionally modifying said thread 18, a zone with a different pitch or modified nut connection tolerance is created, adapted to determine the different torques when tightening: torque in said zone to finally fix valve 1 to transducer 3, after which the operation it may proceed with the torque required to secure the valve-to-transducer assembly on the rim 6.

[0056] The modified thread, in fact, inhibits the movement of the nut 5 on the valve stem 8 until it is securely attached to the transducer 3 and when the resistive torque is overcome by breaking or deforming the modified thread, the nut 5 continues to wind on the other standard thread until valve 1 will not be securely attached to rim 6.

With reference to the cross-section shown in Fig. 5, said element 7 is not directly made on valve 1, but instead is mounted, i.e. superimposed on its pin 8. Said element 7 is configured as a ring adapted for axial mounting on a mandrel 8 and then held in position by a predetermined seat 16 also maintained along the spindle 8 of the valve 1, and substantially adapted to avoid involuntary slipping of the annular member 7 while tightening the cap 5 (Fig. 7a). Said seat 16 may alternatively be replaced by a "nose" or protruding tooth having the same stopping action. In the embodiment shown, the element 7 used irreversibly after the fracture, but in variant embodiments, a type can be selected,

[0059] The valve version in which the element 7 is produced using the materials used seems to be very advantageous, since the element itself, an indicator of achieving a predetermined torque when tightening, can be made of other materials and not of the metal from which it is made nut and the entire valve, depending on the predetermined value of the resistance you want to give to the torque you have when tightening.

[0060] Even more preferably, the annular element 7 can be distinguished by a specific color which can serve to distinguish it, based again on the predetermined value of the resistance it wants to give it.

[0061] Even the shape of the element 7 can be different: Figure 5 shows the ring-shaped element, but alternatively, the shape can be flake and can thus have more protruding sharp teeth that can be broken (or deformed by bending towards the valve body in a variant) in which the element disappears after deformation).

[0062] With reference to the detail shown in Figure 7b, the broken portion 17 of the element 7 is pulled by the nut 5 when it is screwed on: the broken part 17 is positioned between the nut 5 and the valve stem 8 so as to prevent the penetration of corrosive agents between the two threads and to ensure a longer connection life.

In some particularly preferred embodiments of the invention, the portion 19 of the element 7 which remains on the valve stem 8 after being broken (or the part deformed by said element in the event that it irreversibly disappears after deformation) remains visible outside after the nut is fully tightened, and is used to indicate the presence of a TPMS sensor inside the tire.

[0064] The method of assembling the metal valve 1 on the rim 6 according to the invention, in combination with the transducer 3 for TPMS technology, is described below.

[0065] The valve 1 is connected to the transducer 3 and held in position by means of a square-headed screw 4: in this way the valve 1 and the transducer 3 are freely rotating relative to each other while still in communication with each other.

[0066] The valve-to-transducer assembly 10 is then placed on the rim 6, care being taken to place the transducer 3 tangentially against the inner edge of the rim 6, and with the valve stem 1 protruding out of the rim. This operation is performed when the valve is not yet in the cap.

[0067] At this point, it is necessary first of all to securely attach the valve 1 to the transducer 3, and then to tighten the assembly 10 on the rim 6 by tightening the cap 5.

[0068] By acting on the locking nut 5 coaxially with the valve stem 8, a first rotation of said valve is performed which rotates with respect to the transducer 3, which is instead held tangentially to the rim 6.

[0069] The valve 1 rotates simultaneously with the nut 5 until the annular element 7 breaks, and then until the correct torque is reached when tightening, whereby the valve 1 and the transducer 3 are stably connected to each other without any further risk of rotation relative to each other.

[0070] If the cap 5 is still rotated, the valve 1 now remains stationary and the nut 5 rotates on the thread 18 placed on the valve stem 8 until it contacts the rim 6, with the washer 13. At this point, all the elements are connected stable with each other and no further reciprocal rotation is possible.