An Enclosure To Be Embedded In A Tire

Abstract: FORM 2 THE PATENTS ACT, 1970 (39 of 1970) & THE PATENTS RULES, 2003 COMPLETE SPECIFICATION (See section 10, rule 13) 1. Title of the invention: AN ENCLOSURE TO BE EMBEDDED IN A TIRE 2. Applicant(s) NAME NATIONALITY ADDRESS CEAT LIMITED Indian RPG HOUSE, 463, Dr. Annie Besant Road, Worli, Mumbai-Maharashtra, 400 030,  India 3. Preamble to the description COMPLETE SPECIFICATION The following specification particularly describes the invention and the manner in which it is to be performed. TECHNICAL FIELD [0001] The  present  subject  matter  relates,  in  general,  to  an  enclosure  to  be embedded in a tire of a vehicle and, particularly but not exclusively, to an enclosure to be embedded in a tire of a vehicle for encasing various electronic devices measuring various tire parameters. BACKGROUND [0002] Vehicle behavior is directly influenced by tire characteristics. Generally, electronic devices are incorporated in a tire of a vehicle for measuring various parameters of the tire. These parameters may include but not limited to tire pressure, tire positioning w.r.t longitudinal, radial and lateral (X, Y, Z axis) directions with the help of gyroscope sensor, internal temperature of the tire, internal humidity of the tire, angular acceleration and deceleration of the tire, load on the tire, speed of rotation of the tire, distance travelled by the tire, traction of the tire, various types of failure of the tire, and events, such as wear, breaking acceleration and deceleration etc., of the tire. Measurement of these parameters is critical to the performance of the vehicle, optimizing fuel efficiency or driver’s actions in certain situations. Accordingly, the electronic devices measuring the tire parameters must be properly secured to the tire throughout the movement of tire, since improper responses from these electronic devices may adversely affect the vehicle behavior. BRIEF DESCRIPTION OF DRAWINGS [0003] The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to reference like features and components. [0004] Fig. 1 illustrates an enclosure to be embedded in a tire of a vehicle, in accordance with another implementation of the present subject matter. [0005] Figs. 1a and 1b illustrate schematics of a  housing portion and a cover portion, respectively, of the enclosure to be embedded in the tire of the vehicle, in accordance with an implementation of the present subject matter. [0006] Fig.  2  illustrates  top  view  of  the  housing  portion  of  the  enclosure,  in accordance with an embodiment of the present subject matter. [0007] Fig. 3 illustrates three axis of acceleration acting on the tire and to be detected by an electronic device installed in the enclosure embedded in the tire, in accordance with another embodiment of the present subject matter. [0008] Fig.4 illustrates acceleration profile for a single rotation of the tire, in accordance with an implementation of the present subject matter. DETAILED DESCRIPTION [0009] The  present  subject  matter  relates  to  aspects  relating  to  maintaining attachment of electronic devices to a tire by providing an enclosure to be embedded in the tire for encasing the electronic devices, wherein the electronic devices are incorporated in the tire for measuring various tire parameters. [0010] During  movement  of  a  tire,  various  dynamic  forces  act  upon  the  tire. Consequently, these dynamic forces also act upon electronic devices installed in the tire for measuring various parameters associated with the tire. The electronic devices are either permanently anchored to the tire making the electronic devices not serviceable or removably attached to the tire for facilitating serviceability of the electronic devices. Under influence of the dynamic forces that act upon the electronic devices due to movement that the tire undergoes and because of the removable nature of the electronic devices, there is a possibility of the electronic devices to popping out from within the tire. Further, the movement of the tire may cause not only detachment but also displacement of the electronic devices within the tire. [0011] Detachment or displacement of the electronic devices leads to improper or discontinued operation of the electronic devices and may sometimes cause damage to the electronic devices. Accordingly, these electronic devices must be incorporated in the tire in such a manner that these electronic devices can withstand the forces that act upon these electronic devices due to any movement that the tire undergoes and should not be allowed to detach from or displace within the tire. [0012] Further, the orientation of the electronic device needs to be aligned with the axis of the tire to accurately measure a parameter associated with the tire. For example, sensitivity of accelerometer and gyroscope with respect to the movement of their position is high. A 180-degree shift in the electronic device (upside down placement) can cause a significant deviation in the measurements of these electronic devices. Mis-orientation of the accelerometer and gyroscope due to the wrong placement of these electronic devices can disrupt all measurement references. The movement of the tire and the forces acting on the tire or on the electronic devices may lead to displacement of the electronic devices or change in orientation of the electronic devices which results in deviation in the measurements performed by the electronic devices which in turn leads to an inefficient vehicle performance. Errors in the measurements of various tire parameters performed using the electronic devices installed in the tire, need to be minimized for optimized performance of a vehicle and therefore, maintaining the orientation of the electronic devices is also a primary consideration in an installation process when these electronic devices are installed in the tire and during the dynamic movement of the tire. [0013] In conventional designs, generally recesses are provided within the tire to snap fit the electronic device in appropriate orientation and in a removable manner. However, these designs require recesses to be formed in the tire and thus, cannot be suited to all tires or all electronic devices. Also, skilled labor is required for the fitment of the electronic device within the tire. In other designs, either some clips or hooks and other additional components are required to removably insert the electronic device within the tire. Although, these conventional designs may provide snap fit of the electronic device in a particular orientation and in a removable manner, these designs are still susceptible to the risk of detachment/displacement of the electronic devices from /within the tire under the influence of dynamic forces acting on these devices or change in orientation of these electronic device because of dynamic movement and flexible nature of the tire. [0014] An enclosure to be embedded in a tire of a vehicle for encasing various electronic devices and securing attachment of these electronic devices to the tire is described in the present subject matter. In an embodiment, the enclosure overcomes the above-described technical problems associated with the conventional designs available for incorporating electronic devices in tires of vehicles. [0015] In  accordance  with  an  embodiment  of  the  present  subject  matter,  an enclosure to be embedded in a tire of a vehicle may include a housing portion and a cover portion. The housing portion comprises a base and side walls along periphery of the base while the cover portion comprises a flat surface. The housing portion includes three grooves formed in the side walls and the cover portion includes three protrusions located at a circumferential edge of the flat surface. The grooves may be located at equal angular distance from each other. The three protrusions correspond to the three grooves formed on the side walls. The housing portion is fixedly attached to the tire. The cover portion is removably attached to the housing portion by insertion of the three protrusions into the three grooves. [0016] In an exemplary embodiment of the present subject matter, one or more electronic devices may be mounted on the flat surface of the cover portion. The three protrusions located at the circumferential edge of the flat surface of the cover portion are engaged with the three grooves formed in the side walls of the housing portion, when the cover portion is removably attached to the housing portion which is fixedly attached to the tire. This engagement of the protrusions with grooves secures the cover portion to the housing portion, which in turn avoids any change in positioning of the electronic device within the tire and prevents the electronic devices to pop out of the enclosure due to any movement that the tire may undergo and due to the flexible nature of the tire. The equal angular displacement of the three grooves formed in the side walls of the housing portion with each other, ensures that the cover portion having the electronic devices mounted thereon can withstand forces acting upon it due to the dynamic movement of the tire and does not get detached from or displaced within the enclosure, even if the tire deforms at a portion carrying the enclosure because of making a contact with the ground. Thus, easy removability of the electronic devices is achieved maintaining the stability of the attachment of the electronic devices to the tire. [0017] In an embodiment of the present subject matter, the three grooves have a poka-yoke arrangement for insertion of a protrusion from amongst the three protrusions in a corresponding groove from amongst the three grooves, the poka-yoke arrangement being implemented by providing the size of one of the three grooves and one of the three protrusions larger than the size of other grooves and other protrusions. This ensures that removable attachment of the cover portion to the housing portion does not create reliability issues during run time operation of the electronic devices. The positioning and different sizes of the protrusions at the flat surface of the cover portion and the corresponding grooves in the sidewalls of the housing portion are such that the protrusions can be accommodated only in their corresponding grooves providing a poka-yoke arrangement. This arrangement ensures that the electronic devices mounted on the cover portion of the enclosure are installed in the enclosure only in a predefined orientation. Accordingly, the design of the enclosure is such that it facilitates the orientation of the electronic device in-line with the axis of the tire, which in turn facilitates the accuracy and/or sensitivity of the results of the electronic device. Further, it ensures that no displacement in the position of the cover portion and in turn the electronic devices occurs due to any movement that the tire may undergo and flexible nature of the tire. [0018] The above and other features, aspects, and advantages of the subject matter will be better explained with regard to the following description and accompanying figures.  It  should  be  noted  that  the  description  and  figures  merely  illustrate  the principles of the present subject matter along with examples described herein and, should not be construed as a limitation to the present subject matter. It is thus understood that various arrangements may be devised that, although not explicitly described or shown herein, embody the principles of the present disclosure. Moreover, all statements herein reciting principles, aspects, and examples thereof, are intended to encompass equivalents thereof. Further, for the sake of simplicity, and without limitation, the same numbers are used throughout the drawings to reference like features and components. [0019] Fig. 1 illustrates an enclosure 100 to be embedded in a tire (not shown) of a vehicle (not shown), in accordance with another implementation of the present subject matter. While Figs. 1a and 1b illustrate schematics of a housing portion 101 and a cover portion 102, respectively, of the enclosure 100, in accordance with an implementation of the present subject matter. For sake of ease of explanation, Figs. 1, 1a and 1b are explained together. [0020] The  enclosure  100  to  be  embedded  in  the  tire  of  the  vehicle,  in  an implementation of the present subject matter, comprises a housing portion 101 and a cover portion 102. The housing portion 101 may comprise a base 103 and side walls 104 along the periphery of the base 103. Three grooves 105 (105-1, 105-2, 105-3) are provided in the side walls 104. The shape of the housing portion can be any one of circular, triangular, square, rectangular, oval or any other shape that can hold grooves. The cover portion 102 has a flat surface 109 and three protrusions 110 (110-1, 110-2, 11-3) are located at a circumferential edge of the flat surface 109. The three protrusions 110 correspond to the three grooves 105 on the side walls 104. The housing portion 101 is fixedly attached to the tire. The cover portion 102 is removably attached to the housing portion 101 by insertion of the three protrusions 110 into the three grooves 105. The shape of the cover portion can be any one of circular, triangular, square, rectangular, oval or any other shape that can cover the base 103 of the housing portion 101. [0021] The three grooves 105 have a poka-yoke arrangement for insertion of a protrusion from amongst the three protrusions 110 in a corresponding groove from amongst the three grooves 105. The poka-yoke arrangement is implemented by providing the size of one of the three grooves 105-1 and one of the three protrusions 110-1 larger than the size of other grooves 105-2, 105-3 and other protrusions 110-2, 110-3. The poka-yoke arrangement ensures that each of the three protrusions 110 is coupled to the corresponding groove 105 of same size only, when the cover portion 102 is removably attached to the housing portion 101. [0022] In an embodiment of the present invention, one or more batteries 113 may be mounted on the flat surface 109 of the cover portion 102 of the enclosure 100. The one or more batteries 113 serve as a power source for the one or more electronic devices 112 mounted thereon. Easy engagement/disengagement of the protrusions 110 on the cover portion 102 with/from the grooves 105 in the housing portion 101 facilitates serviceability of the electronic devices 112 mounted on the cover portion 102. This also makes the batteries 113 mounted on the cover portion 102 easily replaceable. [0023] In an implementation of the present subject matter, the housing portion 101 is attached to a center of a tire. Attachment of the housing portion 101 to the center of the tire in turn leads to an attachment of the cover portion 102 to the center of the tire because of the poka-yoke arrangement and consequently facilitates alignment of the electronic devices 112 mounted on the cover portion 102 to the center of the tire. The alignment of the electronic devices 112 at the center of the tire is needed as maximum contact length of the tire with the ground is detected through the electronic devices 112 like accelerometer, when such electronic devices 112 are aligned exactly at the center of the tire or close to the center of the tire. This in turn improves the accuracy of the results of the electronic devices 112. [0024] In an example implementation, the housing portion 101 may be provided with orientation guidance markings to enable attachment of the housing portion 101 to the tire at the center of the tire. Accordingly, in one embodiment, the base 103 of the housing portion 101 extends beyond the periphery of the base 103 where the side walls 104 are located. The extended portion 107 of the base 103 comprises orientation guidance markings to enable attachment of the housing portion 101 to the tire at the center of the tire. [0025] In an example, the extended portion 107 comprises a pair of projections 108 located at a peripheral edge of the extended portion 107. This pair of projections 108 serves as orientation guidance markings to enable attachment of the housing portion 101 to the tire at the center of the tire. In another example, orientation guidance markings may be arrow heads or dots engraved or any similar identifier engraved, embossed or otherwise created on the extended portion 107 of the base 103 of the housing portion 101 at the position corresponding to the pair of projections 108. In yet another example, it is also possible to have orientation guidance markings painted on the extended portion 107 of the base 103. [0026] Further example embodiments, where the orientation guidance markings are provided on the base 103 of the housing portion 101 as opposed to the extended portion 107 of the base 103, are also possible. For instance, orientation guidance markings, in the form of a pair of, say red dots, may be painted on the base 103. As will be understood, a position of such orientation guidance markings provided at the base 103 corresponds to the position of the pair of projections 108 provided on the extended portion 107 of the base 103 as shown in the Fig. 1a. [0027] While attaching the housing portion 101 on the tire, the pair of projections 108 enable alignment of center of the housing portion 101 with the center of the tire. In an example embodiment, the center of the tire can be indicated through a marking specified along a centerline of the tire which is situated at a midpoint across the width of the tire. In an example, these markings can be specified in the form of dotted or solid colored lines painted along the centerline of the tire. In another example, these markings  may be dots  or  any similar  identifier  engraved,  embossed  or  otherwise created on the centerline of the tire. The orientation guidance markings on the extended portion 107 of the base 103 of the housing portion 101 are aligned with the marking specified at the centerline of the tire, when the housing portion 101 or the enclosure 100 is attached to the tire. Thus, once housing portion 101 of the enclosure 100 is aligned with the center of the tire, a predefined alignment of the cover portion 102 and in turn that of the electronic devices 112 mounted on the cover portion 102 is also achieved owing to the poka-yoke arrangement for attachment of the cover portion 102 with the housing portion 101. [0028] Fig. 2 shows the top view of the housing portion 101 illustrating angular displacement of the three grooves 105 formed in the sidewalls 104 of the housing portion 101 with each other and with respect to the pair of projections 108. In an example, the three grooves may be located at an angular displacement of 120 degree. The equal angular displacement of the three grooves 105 with each other ensures that the cover portion 102 having the electronic devices 112 mounted thereon does not get misplaced or pop out of the housing portion 101 due to the deformation of the tire. This in turn protects the electronic devices 112 from getting damaged. In another exemplary implementation, the dimension of the enclosure 100 (indicated as m in Fig. 2) including the diameter of the housing portion 101 and length of the pair of projections 108, if these projections are provided as orientation guidance markings on the extended portion 107 of the base 103, may be 85.4±0.2. Further, the diameter of the cover portion (indicated as n in Fig. 2) may be 59.5±0.2. [0029] In an embodiment, the housing portion 101 can be fixedly attached to the tire using an adhesive. In other embodiments, the housing portion 101 can be fixedly attached to the tire by providing cavity inside the tire and inserting the enclosure in the cavity. [0030] In an example embodiment, reinforcing ribs 106 are provided vertically on the side walls 104 of the housing portion 102. These reinforcing ribs 106 provide strength to the enclosure 100. [0031] The cover portion 102 comprising the one or more electronic devices 112 isremovably inserted to the housing portion 101 of the enclosure 100 in such a way that each protrusion 110 on the cover portion 102 is engaged in the corresponding groove 105 of the equivalent size. With such poka-yoke arrangement, the electronic devices 112 mounted on the cover portion 102 are installed in the tire only in a predefined orientation, which enables the alignment of the electronic devices 112 in line with the axis of the tire. Thus, x, y and z- axis of the electronic device 112 are aligned with the corresponding x, y and z- axis (tangential, lateral and radial directions respectively) of the tire for accurate and reliable measurement of tire parameters measured by the respective electronic device 112. For example, a three axis accelerometer is mounted on the flat surface 109 of the cover portion 102 as an electronic device 112 for three axis measurement of the acceleration, with the x-axis measuring the tangential, y-axis measuring the lateral and z-axis measuring the radial acceleration of tire. In this case, since the accuracy of the measured tangential, lateral and radial acceleration of the tire highly depends on the alignment of coordinates of the electronic devices 112 with that of the tire, any misalignment of the axis of the electronic device 112 with that of the tire may lead to incorrect results. The misalignment of the electronic device 112 with that of the tire may happen due to movement and flexible nature of the tire and attachment of the electronic device 112 to the tire in an incorrect orientation. This problem of inaccurate measurement of tire parameter, such as acceleration due to the misalignment of the electronic device 112 with that of the tire is addressed through the herein-explained design of the enclosure 100 to be embedded in the tire for encasing the electronic devices 112. The orientation guidance markings provided on the extended portion 107 of the base 103 of the housing portion 101 of the enclosure 100 ensures that the housing portion 101 is attached to the center of the tire in the predefined orientation to further facilitate the attachment of the cover portion 102 comprising the electronic devices 112 in the same orientation. Further the poka-yoke arrangement ensures that the coordinates of the electronic device 112 mounted on the cover portion 102 of the enclosure 100 is aligned exactly with the axis of the tire, when cover portion 102 is attached to the housing portion 101. The poka-yoke arrangement also ensures that the alignment of the electronic devices 112 is maintained during the movement of the tire. As no misalignment of the electronic devices 112 with that of the tire happens, the errors in the measurements performed through these electronic devices 112 are minimized. [0032] Fig. 3 illustrates the three axis of acceleration acting on the tire that may need to be detected by the electronic device 112 installed in the enclosure 100 embedded in the tire. The components At, Ar, Ac, a and g represents Tangential Acceleration, Radial Acceleration, Centrifugal Acceleration, Tire Forward Acceleration and, Gravity respectively. Angle between the components of gravity and tangential acceleration is represented through θ. [0033] Fig.4 illustrates acceleration profile for single rotation of the tire. The importance of the orientation can be evident through the profile of the various acceleration forces, for example, tangential and radial acceleration components (indicated in Fig. 3), with respect to the tire as shown in Fig. 4. A tire in motion in free space at a constant speed is a body in constant acceleration. However, a tire in motion on the road at a constant speed experiences constant acceleration except when the tire comes in contact with the road. Referring to Fig. 4, the enclosure 100 comprising the electronic devices 112 is placed in a tire at one specific position. When this portion of the tire comes in contact with the road (as specified through the lines S1 and S2 in Fig. 4), there are three major events that take place: (1). The tire experiences a sudden impact at the point of touching the road (with reference to the electronic devices). This is explained by the sudden jump in acceleration upwards. (2) The tire experiences a sudden deceleration as it passes through the contact portion of the road. This is explained by the rapid downward acceleration profile that looks like a braking event. This is due to the resistance of the tire caused by the traction. (3) The tire once again experiences a sudden acceleration as it leaves the road (with reference to the electronic devices). This is explained by the sudden jump in acceleration upwards once again. Once the tire leaves the contact patch, it experiences acceleration of a free body in circular motion. [0034] In an embodiment, the base 103 of the housing portion 101 can be hollow. The hollow base of the housing portion 101 reduces the weight of the enclosure 100 and also does not create additional heat and pressure which can otherwise let the cover portion 102 and correspondingly the electronic devices 112 to pop out from the enclosure 112. Thus, it helps to maintain the pressure equilibrium and prevent heat built up within the enclosure 100, which prevent the cover portion 102 and consequently the electronic devices 112 to pop out from the housing portion 101. [0035] In another embodiment, the enclosure 100 may be made up of rubber. A common rubber, for example, butyl rubber may be used for making an enclosure 100 to be embedded in all types of tires. Alternatively, the enclosure 100 may be made up of the same material as that of the tire. Hence, there is no requirement of introducing any foreign material (plastic or like substrates) within the tire. Other alternative materials that can be used for this purpose include but not limited to Bromobutyl Rubber- 80-100, Natural Rubber- 0-20, Tackifier- 6-8, Carbon Black- 65-75, Zinc Oxide- 2-4, Stearic Acid- 1-2, Stearic Acid- 1-2, Accelerator MBTS- 1-2, MGO- 0-0.5, SULPHUR- 0-0.75 (All ingredients are in parts per hundred of rubber (PHR)). Manufacturing enclosure 100 with the rubber or the like material aids in easy installation of the enclosure 100 within the tire. This also aids in easy insertion/removal of the cover portion 102 of the enclosure 100 in/from the housing portion 101 which is fixedly attached to the tire. This in turn facilitates the easy serviceability of the one or more electronic devices 112 and easy replaceability of the one or more batteries 113 mounted on the cover portion 102. Further, use of the rubber in making of the enclosure 100 also avoids the possibility of popping the cover portion 102 and correspondingly the electronic devices 112 mounted thereon out of the housing portion 101 because of the dynamic movement and flexible nature of the tire. As will be understood, popping out of the cover portion 102 may happen in case of use of plastic and similar material in the making of enclosure 100. This is because, inflexible nature of plastic and similar material may make the enclosure 100 non-compliant with forces that may act upon the enclosure 100 due to dynamic movement of the tire. [0036] In  an  embodiment,  the  electronic  devices  112  are  potted  to  avoid electrostatic discharge (ESD) related risk during replacement of the one or more batteries 113. Since servicing is generally done manually, there is a risk of electro¬static discharge (ESD) because of the human contact, which could damage the electronic devices 112. Thus, the electronic devices 112 are potted to provide protection from static discharge which may happen due to human contact during servicing or replacement of the one or more batteries 113. Accordingly, in an embodiment, electronic devices 112, other than the one or more batteries 113 are potted to avoid electrostatic discharge during servicing of the one or more electronic devices 112. [0037] Although implementations for an enclosure 100 to be embedded in a tire are described, it is to be understood that the present subject matter is not necessarily limited to the specific features of the systems described herein. Rather, the specific features are disclosed as implementations for the enclosure 100 to be embedded in a tire. I/ We claim: 1. An enclosure 100 to be embedded in a tire of a vehicle, the enclosure 100 comprising: a housing portion 101 comprising a base 103 and side walls 104 along periphery of the base 103, the side walls 104 having three grooves 105, the grooves 105 being located at equal angular distance from each other; and a cover portion 102 having a flat surface 109 with three protrusions 110 located at a circumferential edge of the flat surface 109, the three protrusions 110 corresponding to the three grooves 105 on the side walls 104, wherein the housing portion 101 is to be fixedly attached to the tire, and wherein the cover portion 102 is to be removably attached to the housing portion 101 by insertion of the three protrusions 110 into the three grooves 105. 2. The enclosure 100 as claimed in claim 1, wherein the three grooves 105 have a poka-yoke arrangement for insertion of a protrusion from amongst the three protrusions 110 in a corresponding groove from amongst the three grooves 105, the poka-yoke arrangement being implemented by providing the size of one of the three grooves 105-1 and one of the three protrusions 110-1 larger than the size of other grooves 105-2, 105-3 and other protrusions 110-2, 110-3. 3. The enclosure 100 as claimed in claim 1, wherein the housing portion 101 is attached to a centre of the tire. 4. The enclosure 100 as claimed in claim 3, wherein the base 103 comprises an extended portion 107 beyond the periphery of the base 103 where the side walls 104 are located. 5. The enclosure 100 as claimed in claim 4, wherein the extended portion 108 comprises orientation guidance markings to enable attachment of the housing portion 101 to the tire at the centre of the tire. 6. The enclosure 100 as claimed in claim 5, wherein the orientation guidance markings are a pair of projections 108 located at a peripheral edge of the extended portion 107. 7. The enclosure 100 as claimed in claim 1, wherein the housing portion 101 is fixedly attached to the tire using an adhesive. 8. The enclosure 100 as claimed in claim 1, wherein the cover portion 102 comprises one or more electronic devices 112 mounted on the flat surface 109 of the cover portion 102. 9. The enclosure as claimed in claim 8, wherein one or more batteries 113 are mounted on the flat surface 109 of the cover portion 102, the one or more batteries 113 are to serve as power source for the one or more electronic devices 112. 10. The enclosure 100 as claimed in any one of the claims 1 to 9, wherein the enclosure 100 is made up of the rubber. 11. The enclosure 100 as claimed in any one of the claims 1 to 10, wherein the enclosure 100 is made up of the same material as that of the tire.

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