Abstract:
A condition sensor of pneumatic tire is configured to be attached on a pneumatic tire of a vehicle, and the pneumatic tire has a rim with a rim bed. The condition sensor comprises a sensor circuit for detecting the condition of the tire, a power source for supplying the sensor circuit with electric power; and a housing having a cover portion and a base portion, in which the base portion is used to receive the sensor circuit and the power source. The cover portion is provided with an arc-concave surface having a convexity, in which the arc-concave surface is in arc-line contact with the rim bed and the convexity can be used to adjust the relationship position between the housing and the rim bed.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This invention relates to a sensor of pneumatic tire, and more specifically to a condition sensor of pneumatic tire for securely attaching to the rim of the tire.  
           [0003]    2. Description of the Related Art  
           [0004]    It is well known in the prior art that a variety of devices can be used to inspect the pressure of the pneumatic tire of vehicle, such as U.S. Pat. No. 4,048,614 entitled “Low Tire Pressure Warning Device”, issued to Shumway on Sep. 13, 1997, which discloses a tire warning device for pneumatic tires of a vehicle. The tire warning device is mounted to the wheel rim and has an actuatable radio transmitter, a power source, a switch, and a diaphragm means. The radio transmitter can be actuated to warn the driver when the pressure of the tire is below a predetermined low pressure. The warning device described above only warns the driver of the low pressure of the tire, and is constructed with complex structure which is not adapted to the modern vehicle.  
           [0005]    U.S. Pat. No. 5,844,131 entitled “Tire Pressure Sensor Apparatus For A Pneumatic Tire Of A Vehicle”, issued to Gabelmann et al. on Dec. 1, 1998, discloses a pressure sensor device comprising a housing having at least two base elements for resting on a rim bed of a tire rim and for adjustably supporting the housing in a mounted state. As mentioned above, since the rim bed is cylindrical or barrel shape, the housing is supported to the rim bed by the two base elements when it is mounted on the rim bed. However, due to the vehicle jolting along, such a two-point contact is often loosened and the housing cannot be securely mounted on the rim bed. Besides, the sensor device is mounted on the rim of the tire by the two base elements as well as a tire valve and a hollow screw attached thereto, but this arrangement needs cooperating with three contact points, and thus it is difficult to install and to mount the sensor device on a variety of rims. Also, the antenna member is necessary for the pressure sensor, and it is extended from the housing. When the tire is repaired, the antenna member will be often damaged by the repairing tools, and then the pressure sensor will be replaced.  
           [0006]    Moreover, U.S. Pat. No. 6,055,855 entitled “Tire Pressure Sensor Wheel Attachment Apparatus”, issued to Straub on May 2, 2000, discloses an apparatus for mounting a pressure sensor on a rim of a vehicle wheel, in which the apparatus comprises a pressure sensor and a threaded fastener, and the pressure sensor can be mounted on the rim of the wheel by the threaded fastener and a tire valve stem. The mounting effect only from the tire valve stem cannot provide sufficient support to meet the requirement of the apparatus. Furthermore, this apparatus includes a spherical surface to be adjustably attached on the rim, but this spherical surface will substantially decrease the stability of the apparatus.  
           [0007]    Therefore, the tire pressure sensor as described hereinbefore cannot be securely mounted on the rim of the wheel, and a need exists therefor to provide a suitable pressure device to be securely attached to the rim of the tire of vehicle so as to inspect the tire condition at any time.  
         SUMMARY OF THE INVENTION  
         [0008]    It is the primary object of the present invention to provide a condition sensor of a pneumatic tire to inspect the condition of the tire, in which the condition sensor can be securely mounted to the rim of the tire and interact with receiver means outside of the tire.  
           [0009]    It is another object of the present invention to provide a condition sensor of a pneumatic tire to inspect the condition of the tire, in which the condition sensor is mounted to the rim of the tire and is constructed as a relatively compact structure such that the condition sensor will not be damaged by the tire repairing tools.  
           [0010]    It is a further object of the present invention to provide a condition sensor of a pneumatic tire to inspect the condition of the tire, in which the condition sensor has an adjustable structure so as to facilitate the securely attachment of the condition sensor on the rim of the tire.  
           [0011]    In order to achieve the above objects, the condition sensor of pneumatic tire according to the present invention is configured to be attached on a pneumatic tire of a vehicle, and the pneumatic tire has a rim with a rim bed. The condition sensor comprises a sensor circuit to detect the condition of the tire, a power source to supply the sensor circuit with electric power; and a housing having a cover portion and a base portion, in which the base portion is used to receive the sensor circuit and the power source. The cover portion is provided with an arc-concave surface having a convexity, in which the arc-concave surface is in arc-line contact with the rim bed and the convexity can be used to adjust the relationship position between the housing and the rim bed.  
           [0012]    According to one aspect of the present invention, the condition sensor of pneumatic tire further comprises a valve stem cavity having a hole and a tire valve stem, the rim of the tire having a tire valve hole, and the condition sensor being adjustably mounted on the tire valve hole by means of the valve stem cavity.  
           [0013]    According to another embodiment of the present invention, the condition sensor of pneumatic tire is configured to be attached on a pneumatic tire of a vehicle, and the pneumatic tire having a rim with a rim bed. The condition sensor comprises a sensor circuit to dectect the condition of the tire, a power source to supply the sensor circuit with electric power, a housing to receive the sensor circuit and be mounted on the rim bed, the housing has a cover portion and a base portion, in which the base portion is used to receive the sensor circuit and the power source and comprise two grooves, and the cover portion is provided with a valve stem cavity and a tire valve stem, and the rim having a tire valve hole; and two one-way sliders to cooperate with the two grooves such that the one-way slider can slide inside the groove in one way and the condition sensor can be securely mounted on the tire valve hole by means of the tire valve stem through the valve stem cavity and the two one-way sliders.  
           [0014]    According to another aspect of the present invention, the condition sensor of pneumatic tire further comprises an antenna to transmit radio signal and interact with receiver means outside of the tire, the antenna is arranged alone the surface of the base portion to reduce the probability of the antenna being damaged.  
           [0015]    According to the present invention, since the condition sensor of pneumatic tire is provided with an arc-concave surface to fit with the rim bed of the pneumatic tire, the condition sensor can be securely attached to the rim of the tire. Also, the condition sensor has an antenna member without any protruding structure, and thus the antenna member of the condition sensor will not be damaged during repairing of the tire. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.  
         [0017]    [0017]FIG. 1 is a perspective view of a condition sensor of a pneumatic tire of a vehicle according to an embodiment of the present invention.  
         [0018]    [0018]FIG. 2 is a perspective exploded view of the condition sensor of a pneumatic tire shown in FIG. 1.  
         [0019]    [0019]FIG. 3 is a perspective view of the condition sensor of a pneumatic tire shown in FIG. 1 and  2  from an alternate direction.  
         [0020]    [0020]FIG. 4 is a cross-section view of the condition sensor of a pneumatic tire according to the embodiment of the present invention.  
         [0021]    [0021]FIG. 5 is a cross-section view of the condition sensor mounted on a rim of a pneumatic tire according to the embodiment of the present invention.  
         [0022]    [0022]FIG. 6 is a cross-section view of the condition sensor mounted on a rim of a pneumatic tire according to the embodiment of the present invention.  
         [0023]    [0023]FIG. 7 is a perspective view of the condition sensor of a pneumatic tire according to another embodiment of the present invention.  
         [0024]    [0024]FIG. 8 is an enlarged perspective view of the one-way slider of the condition sensor of a pneumatic tire shown in FIG. 7.  
         [0025]    [0025]FIG. 9 is a perspective view of the condition sensor of a pneumatic tire according to also another embodiment of the present invention.  
         [0026]    [0026]FIG. 10 is a perspective view of the condition sensor of a pneumatic tire according to still another embodiment of the present invention.  
         [0027]    [0027]FIG. 11 is a perspective view of the condition sensor of a pneumatic tire according to also another embodiment of the present invention.  
         [0028]    [0028]FIG. 12 is an enlarged cross-section schematic view of the flaring recess of the condition sensor shown in FIG. 11.  
         [0029]    [0029]FIG. 13 is a cross-section view of the condition sensor of a pneumatic tire mounted on the rim of the pneumatic tire according to another embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0030]    Now referring to FIGS. 1, 2, and  3 , they depict a condition sensor  10  of the pneumatic tire of vehicle according to the present invention. The condition sensor  10  includes a housing having a base portion  17  and a cover portion  11  attached to the base portion  17  by a bolt  33  and a thread hole  29 . The base portion  17  substantially includes two compartments for receiving a sensor circuit  25  and a battery seat  13  with a battery  15  deposed therein, respectively.  
         [0031]    The central portion of the base portion  17  is provided with a value stem cavity  51  having an elongated hole  53  with a tire valve stem  19  extending therethrough. The tire valve stem  19  has a stopper  55  of which one end is provided with a substantially arc-shape shoulder  56  and the elongated hole  53  is also provided with an arc-shape shoulder  35  such that the tire valve stem  19  pivots with relation to the base portion  17  on the curvature centrum of the arc-shape shoulder  35 , when the tire valve stem  19  is mounted into the elongated hole  53  and fixed by a nut  31 . Also, the nut  31  further comprises a washer  38 , and both of the nut  31  and the washer  38  have indented grain so as to allow the nut  31  securely being attached on the tire valve stem  19  without loosing due to the vehicle jolting alone.  
         [0032]    Now referring to FIG. 4, it depicts a cross-section of the condition sensor  10  of the pneumatic tire. Since the cover portion  11  of the housing is contacted with a rim bed when the condition sensor  10  is attached on the vehicle wheel (described in detail hereinafter), the surface of the printing circuit board of the sensor circuit  25  on which the electronic elements is attached must face the cover portion  11  to keep the stability of the sensor circuit  25  from the effect of the centrifugal force during driving. The sensor  25  substantially includes a sensor application-specific integrated circuit (ASIC)  47 , the ASIC is available from model IB01290 manufactured by the LITE-ON Inc., which can be used to dectect the pressure and the temperature.  
         [0033]    Moreover, it will be appreciated by those skilled in this art that a tire pressure sensor known in the related art has a sensor application-specific integrated circuit (ASIC), and the sensor ASIC and the battery are encapsulated together therein, so the entire tire pressure sensor should be replaced when the battery is dead. Alternatively, since the condition sensor  10  according to this invention is provided with the battery seat  13  for mounting the battery  15  and the cover portion  11  is removable mounted on the base portion  17 , the battery  15  can be securely mounted onto the base portion  17  by means of the battery seat  13  and is replaceable.  
         [0034]    Now referring to FIG. 5, the condition  10  of the pneumatic tire of the vehicle is mounted on a rim  43  by the tire valve stem  19  and a nut  21 . Referring to FIG. 4 and  5 , the cover portion  11  of the condition sensor  10  is provided with an arc-concave surface  45  having a convexity. The curvature of the arc-concave portion of the arc-concave surface  45  having a convexity is the same as that of the rim bed  42  of the tire, so the surface  45  will be in arc-line contact with the rim bed  42  of the rim  43  when the condition sensor  10  is attached on the rim  43  such that the condition sensor  10  can be more securely mounted on the rim  43 .  
         [0035]    Moreover, it will be appreciated by those skilled in this art that a tire pressure sensor known in the related art is provided with a tire valve stem having a spherical stopper, so the tire valve stem shall be affixed by a specific tool when a nut is screwed thereon and hence it is difficult to install the tire pressure sensor. The tire valve stem  19  of the condition sensor  10  according to the present invention has an arcuated shoulder  56  to keep the tire valve stem  19  from rotating, when the nut  31  is screwed thereon to mount the tire valve stem  19 , such that the condition sensor  10  can be rapidly mounted on the rim  43 .  
         [0036]    Also, the sensor circuit  25  of the condition sensor  10  is interacting with receiver device by a radio signal to inspect the tire, so the sensor circuit  25  must have an antenna  23  to transmit the radio signal. As shown in FIG. 2 and  3 , the antenna  23  is constructed as a specific shape arranged alone the surface of the base portion  17  of the condition sensor  10 . As shown in FIGS. 5 and 6, the antenna  23  is set on the surface of the base portion  17 . When the tire  41  is removed from the rim  43 , the tire  41  will be moved relative to the condition sensor  10  (showing in the FIG. 6) and the antenna will not be damaged.  
         [0037]    As mentioned above, the condition sensor  10  is used to detect the condition of a pneumatic tire, such as pressure and temperature, and thus the cover portion  11  of the condition sensor  10  according to the present invention further comprises two through holes  27  such that the condition of the tire can be sensed by the sensor circuit  25 . It will be appreciated by those skilled in this art that there is moisture inside of the pneumatic tire. In the conventional sensor of the pneumatic tire, a specific material membrane is often used to keep the circuit of the sensor from effect of the moisture in the tire while the sensor can detect the pressure and the temperature of the tire. For this reason, the diameter of the though hole  27  of the condition  10  according to the present invention is preferably less than 0.5 mm, and the perimeter surface of the hole  27  is provided with protrusion (not shown) such that the sensor  25  can detect the condition of the tire while keeping the moisture from entering the condition sensor  10 .  
         [0038]    Furthermore, referring to FIG. 7, it depicts a condition sensor  100   a  of the pneumatic tire of vehicle according to another embodiment of the present invention. The condition sensor  100   a  is similar to the condition sensor  10 , and the similar elements have been designated by the similar reference numerals. The condition sensor  100   a  further comprises two one-way sliders  161   a,  and the base portion  117   a  of the condition sensor  100   a  has two grooves  162   a.  The two one-way sliders  161   a  are provided with indent pawls  163   a  cooperating with indent notches on the two grooves  162   a  such that the two one-way sliders  161   a  can slide inside the two grooves  162   a  in one way direction. Therefore, while the condition sensor  100   a  is attached on the rim bed of the tire and the cover portion is in arc-line contact with the rim bed, the two one-way slides  161   a  will be further slided into the two grooves  162   a  to further securely mount the condition sensor  100   a  so as to avoid the condition sensor  100   a  vibrating during driving.  
         [0039]    Also, as shown in FIG. 8, the one-way slider  161   a  further comprises a slot  166   a,  which is used to increase the flexibility thereof when the the one-way slider  161   a  slides into the groove  162   a.    
         [0040]    Now referring to FIG. 9, it depicts a condition sensor  100   b  of the pneumatic tire of vehicle according to a third embodiment of the present invention. The condition sensor  100   b  is similar to the condition sensor  100   a,  and the similar elements have been designated by the similar reference numerals. The condition sensor  100   b  has another type of one-way sliders  161   b  that is similar to the one-way sliders  161   a,  and the only difference is that the indent pawls  163   b  of the one-way slider  161   b  is deposited on the top of the one-way slider  161   b  and the indent notches  164   b  is also deposited on the top of the groove  162   b  (shown as the dash lines in FIG. 9) such that the two one-way sliders  161   b  can slide inside the two grooves  162   b  in one way, respectively.  
         [0041]    Now referring to FIG. 10, it depicts a condition sensor  100   c  of the pneumatic tire of vehicle according to a further embodiment of the present invention. The condition sensor  100   c  is similar to the condition sensor  100   a,  and the similar members have been designated by the similar reference numerals. The condition sensor  100   c  has another type of one-way sliders  161   c  that is similar to the one-way sliders  161   a,  and the only difference is that the one-way slider  161   c  has a fin extended from one side thereof and the indent notches  164   b  is deposited on the only one side of the groove  162   b  such that the two one-way sliders  161   c  can slide inside the two grooves  162   c  in one way, respectively.  
         [0042]    Referring to FIGS. 11 and 12, they depict a condition sensor  200  of the pneumatic tire of vehicle according to another embodiment of the present invention. The condition sensor  200  is similar to the condition sensor  100 , and the similar elements have been designated by the similar reference numerals. The condition sensor  200  further comprises two flaring recesses  263 , which is deposed on the junction of the antenna  223  and the base portion  217 . When the tire is repaired, the flaring recess  263  is used to keep the antenna  223  from damaging due to unduly bending.  
         [0043]    Now referring FIG. 13, it depicts a condition sensor  300  of the pneumatic tire of vehicle according to another embodiment of the present invention. The condition sensor  300  is similar to the condition sensor  100 , and the similar elements have been designated by the similar reference numerals. The condition sensor  300  comprises a valve stem cavity  351 , which has a conical hole  353  with a tire valve stem  319  extending therethrough. The tire valve stem  319  comprises a stopper  355 . The one end of the stopper  355  has a substantially conical shoulder  335  and the conical hole  353  also has an arcuated shoulder  335  such that the tire valve stem  319  can be mounted by a nut  331  when it is inserted into the conical hole  353 . Also, the nut  331  further comprises a washer  332 , and the nut  331  and the washer  332  have indented grain  338  so as to allow the nut  331  securely attaching on the tire valve stem  319  without loosing due to the vehicle jolting alone.  
         [0044]    As mentioned above, the condition  300  is used to detect the condition of a pneumatic tire, such as pressure and temperature, and thus the cover portion  311  of the condition sensor  10  according to the present invention further comprises two through holes such that the condition of the tire can be detected by the sensor circuit. It will be appreciated by those skilled in this art that there is moisture inside of the pneumatic tire. The diameter of the though hole of the condition  300  according to the present invention is preferably less than 0.5 mm, and the perimeter surface of the hole  27  is provided with protrusion such that the sensor  25  can detect the condition of the tire while keeping the moisture from entering the condition sensor  300 .  
         [0045]    Furthermore, the condition sensor  300  further comprises two one-way sliders, and the base portion  317  of the condition sensor  300  has two grooves. As described hereinbefore, the two one-way sliders can cooperating with the two grooves such that the two one-way sliders can slide inside the two grooves in one way. Therefore, while the condition sensor  300  is attached on the rim bed of the tire, the two one-way slides will be further slided into the two grooves to further securely mount the condition sensor  300  so as to keep the condition sensor  300  from loosing due to the vehicle jolting alone.  
         [0046]    Although the preferred embodiments of the invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.