Connecting member for an air maintenance tire and method of forming the same

A connecting member and method of forming the connecting member in an air maintenance tire is provided. The method includes providing a tire having a sidewall formed with an annular groove. The groove receives an annular air tube having a first end with a first fitting and a second end with a second fitting. A recess is formed in the tire sidewall along the annular groove at a location where the first end of the annular air tube is adjacent the second end of the annular air tube. A mold formed with a cavity is provided and the fittings are removably secured in the cavity. The mold is positioned on a surface of the tire sidewall and an elastomer or a polymer is introduced into the mold cavity. The mold is heated to form the connecting member on the tire sidewall.

FIELD OF THE INVENTION

The invention relates to air maintenance tire systems, which are systems that maintain appropriate air pressure within a pneumatic tire. More specifically, the invention relates to a connecting member of a valve stem-based air maintenance tire system. The invention is directed to a durable connecting member and an efficient and reliable method for forming the connecting member in a sidewall of a tire.

BACKGROUND OF THE INVENTION

Conventional pneumatic tires are designed to perform for relatively long periods of time. In many cases, automobile tires are now expected to have a useful service life of 30,000, 50,000 or 70,000 miles. However, even long-life pneumatic tires are subject to air pressure losses due to puncture by nails and other sharp objects, temperature changes, and/or diffusion of air through the tire itself.

Since air diffusion reduces tire pressure over time, the pneumatic tires may repeatedly become underinflated. Accordingly, drivers must in turn repeatedly act to maintain recommended air pressures in the vehicle tires to avoid reduced fuel economy, tire life, and/or vehicle braking and handling performance. Tire pressure monitoring systems (TPMS) are automated systems that have been proposed to warn drivers when the air pressure in the vehicle tires is significantly low. Such systems, however, remain dependent upon a driver taking remedial action, when warned, to re-inflate a tire to the recommended pressure. It had thus been desirable in the prior art to incorporate an air maintenance feature within a pneumatic tire that would maintain a predetermined or recommended air pressure without requiring driver intervention.

To this end, air maintenance tire (AMT) systems have been developed. An AMT system typically includes one or more pumps or pumping assemblies that act to increase the air pressure in the vehicle tires as needed. An example of one such system is a valve stem-based air maintenance tire system described in U.S. patent application Ser. No. 15/065,134, which is owned by the same Assignee as the present invention, that is, The Goodyear Tire & Rubber Company.

In such AMT systems, and particularly valve stem-based AMT systems, an annular air tube is disposed in a sidewall of the tire and is sequentially flattened or squeezed by the tire footprint as the tire rotates, which directs air to a valve housing. The valve housing is disposed within a wheel rim and is fluidly connected to a tire valve stem, which in turn is in fluid communication with the tire cavity. To enable the fluid communication of air from the annular air tube to the valve housing, one or more connecting tubes extend between the annular air tube and the valve housing. To provide a secure connection point between the annular air tube and the connecting tubes, a mounting member is secured to the sidewall of the tire.

The mounting member is often referred to as a dome. The dome is an important part of a valve-stem based AMT system, as it preserves the fluid connection between the annular air tube and the connecting tubes. In the prior art, the dome has been pre-formed and then separately attached to the sidewall of the tire. Such a manner of forming and securing the dome to the tire sidewall is inefficient and may not provide optimum reliability.

It is therefore desirable to provide a durable connecting member and an efficient and reliable method for forming the connecting member in an air maintenance tire.

SUMMARY OF THE INVENTION

According to an aspect of an exemplary embodiment of the invention, a method of forming a connecting member in an air maintenance tire includes providing a tire with a sidewall. The sidewall is formed with an annular groove that receives an annular air tube and the annular air tube includes a first end receiving a first fitting and a second end receiving a second fitting. A recess is formed in the tire sidewall along the annular groove at a location where the first end of the annular air tube is adjacent the second end of the annular air tube. A mold is provided that is formed with a cavity. The first fitting is removably secured in the cavity and the second fitting is removably secured in the cavity. The mold is positioned on a surface of the tire sidewall and at least one of an elastomer and a polymer is introduced into the mold cavity. The mold is heated and the connecting member is formed on the tire sidewall.

According to an aspect of another exemplary embodiment of the invention, a connecting member is provided and is formed according to the exemplary steps described in the paragraph above.

DETAILED DESCRIPTION OF THE INVENTION

It is to be understood that the term inboard or inboardly is referred to herein as a direction corresponding to the axially inner surface or side of a tire, and the term outboard or outboardly is referred to herein as a direction corresponding to the axially outer surface or side of a tire. The term axially inwardly refers to an axial direction that is toward the center plane of a tire, and the term axially outwardly refers to an axial direction that is away from the center plane of a tire. The term radially inwardly refers to a radial direction that is toward the central axis of rotation of a tire, and the term radially outwardly refers to a radial direction that is away from the central axis of rotation of a tire.

Turning toFIG. 1, a tire12is mounted on a rim14in a conventional manner as known to those skilled in the art and defines a cavity (not shown). An exemplary air maintenance tire system, such as a valve stem-based air maintenance tire system, is indicated at16. The air maintenance tire system16includes a peristaltic pump assembly18. The peristaltic pump assembly18includes an annular air tube20that is received in an annular groove38formed in a sidewall34of the tire12and/or rim14, and in turn encloses an annular passageway (not shown).

A first connecting tube22attaches to a first end24of the annular air tube20and fluidly connects the first end of the annular air tube to a valve housing26of the pump assembly18. A second connecting tube28attaches to a second end30of the annular air tube20and fluidly connects the second end of the annular air tube to the valve housing26.

When the tire12rotates under load along a ground surface, the annular air tube20is sequentially flattened or squeezed at the tire footprint. The sequential flattening of the annular air tube20and its passageway, segment by segment, directs air to the valve housing26. A tire valve stem (not shown), including a check valve, is fluidly connected to the valve housing26and is in fluid communication with the tire cavity. When the air pressure is sufficient against the check valve and the air pressure within the tire cavity is below a set pressure level, air passes into the tire cavity. When the air pressure level within the tire cavity is at or above the set pressure, the check valve closes and air from the pump assembly18is vented by a relief valve in the valve housing26to atmosphere.

As seen inFIG. 1, the valve housing26of the pump assembly18is disposed within the rim14. The connecting tubes22,28pass through an opening36formed in the rim14and extend to a fairly rigid elastomer or polymer mounting member32, which is referred to as a dome. The dome32is secured to the sidewall34of the tire12, and facilitates the fluid connection of the first connecting tube22to the first end24of the annular air tube20through a first fitting40and the fluid connection of the second connecting tube28to the second end30of the annular air tube through a second fitting42. In the prior art, the dome32has been pre-formed and then separately attached to the tire sidewall34, which is inefficient and may not provide optimum reliability.

The connecting member and method of forming the connecting member in an air maintenance tire of the present invention is referred to generally at50and is shown inFIGS. 2 through 8. An exemplary connecting member52, also referred to as a dome, formed by the method50of the present invention is shown inFIG. 8. For the purpose of convenience, the numbering of components inFIGS. 2 through 8, with the exception of dome52, will remain consistent with the numbering of components inFIG. 1.

Turning now toFIG. 2, the connecting member and method of forming the connecting member in an air maintenance tire50includes forming a recess54in the tire sidewall34at a predetermined point along the annular groove38. More particularly, the recess54is formed at the location where the first end24of the annular air tube20is adjacent the second end30of the annular air tube. The first fitting40and the second fitting42each are received in the recess54. The recess54is of a sufficient depth to receive the fittings40and42, while not intruding upon the tire cavity. The recess54preferably is formed in the tire12after the tire has been cured or vulcanized.

An undercut56preferably is formed about the radially inward periphery58of the recess54and the radially outward periphery60of the recess. The undercut56enables mechanical engagement of the dome52(FIG. 8) with the tire sidewall34, as will be described in greater detail below. A first relief area62preferably is formed adjoining the recess54along the annular groove38about the first end24of the annular tube20, and a second relief area64preferably is formed adjoining the recess along the annular groove about the second end30of the annular tube. Each relief area62and64enables easy temporary elevation of the fittings40and42away from the annular groove38for the formation of the dome52, as will be described in greater detail below.

Referring toFIGS. 3 and 4, the fittings40and42(FIG. 2) are temporarily moved out of the recess54. Adhesive material such as a solid adhesive66, including an adhesive or rubber patch66(FIG. 3), and/or a flowable adhesive68(FIG. 4), including rubber cement, glue, epoxy and the like, is introduced into the recess54. Preferably the flowable adhesive68is also introduced into the first relief area62and the second relief area64.

As shown inFIG. 5, when the fittings40and42are moved out of the recess54, they are removably secured to a mold70. More particularly, the mold70includes a mold body72that includes an interior surface76formed with a cavity74. The cavity74is sized to cover the recess54and the relief areas62,64(FIG. 2). Each one of a pair of openings78and80are formed in the mold body72and extend from the cavity74to an exterior surface82(FIG. 6) of the mold body. The first fitting40is inserted into a respective one of the openings78and the second fitting42is inserted into the other respective one of the openings80. The fittings40and42are preferably formed of a rigid material, such as brass, copper, steel or other metal, or of a rigid, high-melting point plastic or composite. By being formed of such materials, the fittings40and42are robust and firmly engage the openings78and80during curing of the dome52, as will be described in greater detail below. It is to be understood that the fittings40and42may be of various constructions and may include supporting features, such as hose-supporting springs84.

The openings78and80formed in the mold body72thus secure the relative position of each fitting40and42in the mold cavity74, and prevent material from flowing into a pneumatic opening86(FIG. 8) of each respective fitting. Such prevention of material flow into each pneumatic opening86preserves fluid communication between the connecting tubes22,28(FIG. 1) and the annular tube20. Once the fittings40and42are inserted into respective openings78and80, a selected elastomer or polymer is introduced into the mold cavity74. The elastomer or polymer may be in a solid form, such as pellets, strips or particulate matter, and packed into the mold cavity74before the mold body72is placed into contact with the tire12. Alternatively, the elastomer or polymer may be in a molten or flowable form, and may thus be flowed into the mold cavity after the mold body72is placed into contact with the tire12.

Turning now toFIGS. 6 and 7, the mold body72is positioned on the surface of the tire sidewall34. When the mold body72is positioned on the tire sidewall34, the fittings40and42are seated in the recess54(FIG. 2), the first end24of the annular tube20is seated in the first relief area62and the second end30of the annular tube is seated in the second relief area64. The mold body72preferably is secured in position against the sidewall34of the tire12by mechanical means, such as fasteners or dowel pins. A platen88(FIG. 7) is placed into contact with the mold body72to provide pressure and/or heat to the mold70.

The mold body72remains in contact with the tire sidewall34as forming and curing of the dome52takes place. The pressure created in the mold cavity74, the temperature created in the mold cavity and the amount of time that the mold body72is pressed against the tire sidewall34are all dictated by the specific elastomer or polymer that is selected for introduction into the mold cavity. For example, for most elastomers or polymers that may be is introduced into the mold cavity74, the temperature in the cavity may be from about 150 to about 170 degrees Celsius and the molding time may be from about fifteen to about thirty minutes.

During the molding process, the elastomer or polymer in the mold cavity74flows about the fittings40and42in the cavity and the recess54, and combines with the solid adhesive66and the flowable adhesive68to form the dome52shown inFIG. 8. In this manner, the dome52is formed as an integral component on the tire sidewall34. The flowing of the elastomer, polymer and/or adhesive into the undercut56about the recess54creates a positive mechanical interlock of the dome52and the tire sidewall34. The dome52is further secured to the tire sidewall34by the adhesive64,68.

The connecting member and method of forming the connecting member in an air maintenance tire50is efficient and reliable and produces a durable dome52. The dome52includes a semi-rigid structure that is capable of flexing when needed, while being a stable structure that is formed on and securely attached to the sidewall34of the tire12. Such a stable structure for the dome52preserves the connection of the annular air tube20to the connecting tubes22and28and maintains the integrity of the connection as the tire12rotates.

As described above, the present invention includes a method of forming a connecting member in an air maintenance tire50. The method includes steps in accordance with the description that is presented above and shown inFIGS. 2 through 8.

It is to be understood that the structure of the above-described connecting member and/or the steps of the above-described method of forming the connecting member in an air maintenance tire may be altered or rearranged, or components or steps known to those skilled in the art omitted or added, without affecting the overall concept or operation of the invention.

The invention has been described with reference to a preferred embodiment. Potential modifications and alterations will occur to others upon a reading and understanding of this description. It is to be understood that all such modifications and alterations are included in the scope of the invention as set forth in the appended claims, or the equivalents thereof.