Patent Publication Number: US-2023158843-A1

Title: Valve stem and tire valve

Description:
TECHNICAL FIELD 
     The present disclosure relates to a valve stem that is fixed in a state of penetrating a valve mounting hole of a tire wheel and accommodates a valve core, and a tire valve including the valve stem. 
     BACKGROUND ART 
     Conventionally, a tire valve that connects an electric circuit on a distal end side and an electric circuit on a proximal end side of the tire valve by way of a valve core is known (see e.g., Patent Document 1). In this tire valve, the electric circuits can be connected to each other when the valve cap is attached. 
     RELATED ART DOCUMENT 
     Patent Document 
     Patent Document 1: WO 2019/194303 (Paragraphs [0026], [0027], etc.) 
     SUMMARY OF THE INVENTION 
     Problems to be Solved by the Invention 
     However, in the conventional configuration described above, there is a problem that the electric circuits cannot be connected to each other while the valve cap is removed, for example, when air is being supplied into the tire. 
     Means of Solving the Problems 
     A valve stem according to one aspect of the present disclosure made to solve the above problems is a valve stem that has a tubular structure, is fixed in a state of penetrating a valve mounting hole of a tire wheel, and accommodates a valve core, the valve stem including: a pair of internal electrodes connected to an internal circuit in a tire; a pair of external electrodes arranged on an outer peripheral surface of a tire outer protruding portion protruding to an outside of the tire in the valve stem and connectable to an external circuit outside the tire; and first and second conductive members having the internal electrodes and the external electrodes and insulated from each other. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a cross-sectional view of a tire wheel to which a tire valve including a valve stem according to a first embodiment of the present disclosure is attached. 
         FIG.  2    is a cross-sectional side view of the valve stem. 
         FIG.  3    is a perspective view of the valve stem. 
         FIG.  4 (A)  is an enlarged perspective view of the periphery of a side surface through-hole of the valve stem, and  FIG.  4 (B)  is a perspective view of an inner sleeve. 
         FIG.  5 (A)  is an enlarged cross-sectional side view of the periphery of the side surface through-hole of the valve stem to which a connector is attached,  FIG.  5 (B)  is a perspective view of the connector viewed from the inner side of a stem main body through the side surface through-hole, and  FIG.  5 (C)  is a front view of the connector. 
         FIG.  6 (A)  is an enlarged cross-sectional side view of a proximal end portion of the valve stem, and  FIG.  6 (B)  is a perspective view of a connection terminal of the connector. 
         FIG.  7 (A)  is a perspective view of a tire valve including a valve stem according to a second embodiment, and  FIG.  7 (B)  is a perspective view of first and second conductive members. 
         FIG.  8 (A)  is a cross-sectional plan view of the vicinity of an external electrode of the valve stem according to the second embodiment, and  FIG.  8 (B)  is a cross-sectional plan view of a portion near a proximal end of the valve stem according to the second embodiment. 
     
    
    
     MODE FOR CARRYING OUT THE INVENTION 
     First Embodiment 
       FIG.  1    shows a tire valve  100  including a valve stem  10  of a first embodiment. The tire valve  100  of the present embodiment is mounted in a valve mounting hole  81 H provided in a rim  81  of a tire wheel  80 . Specifically, a proximal end portion of the valve stem  10  of the tire valve  100  is fitted and fixed in a state of penetrating the valve mounting hole  81 H. When the tire valve  100  is mounted to the tire wheel  80 , a distal end side portion of the valve stem  10  having an air injection port  18  (see  FIG.  2   ) protrudes to the outside of the tire  82 . 
     As shown in  FIG.  2   , the valve stem  10  has a tubular structure in which the outer side of a stem main body  11  having a circular tubular shape is covered with an elastic seal member  12 . Specifically, a proximal end portion of the stem main body  11  is covered with the elastic seal member  12 , and a distal end side portion of the stem main body  11  is exposed from the elastic seal member  12 . An air flow hole R that communicates the inside and the outside of the tire  82  with each other is provided on the inner side of the stem main body  11 . The distal end of the stem main body  11  is provided with the air injection port  18  described above for injecting air into the tire  82 . A male thread portion  16  is formed on an outer peripheral surface of a distal end portion of the stem main body  11 , and a valve cap  19  is screwed onto the male thread portion  16  from the outer side. The stem main body  11  has conductivity and, for example, is made of metal. 
     A small-diameter hole portion  11 S having the narrowest inner diameter is formed at a position near the distal end of the air flow hole R of the stem main body  11 . A straight hole portion  11 B having a larger diameter than the small-diameter hole portion  11 S extends to the proximal end of the stem main body  11  on the proximal end side of the small-diameter hole portion  11 S in the air flow hole R. A proximal end side small-diameter portion  11 A whose outer diameter is reduced and which extends to the proximal end of the stem main body  11  is formed at the proximal end portion of the stem main body  11 . An annular gap is formed between an outer peripheral surface of the proximal end side small-diameter portion  11 A and an inner peripheral surface of the elastic seal member  12 . 
     A valve core  20  is accommodated inside the stem main body  11 . The outer peripheral surface of the valve core  20  is sealed with the inner peripheral surface of the stem main body  11 , and the air flow hole R is opened and closed by opening and closing of the valve core  20 . Specifically, the valve core  20  is supported by a tubular fixing base  29  in a state where a shaft  22  is inserted in a linearly movable manner. By linearly moving the shaft  22 , a valve body  21  at the end portion of the shaft  22  opens and closes a valve port  20 K at the proximal end portion of the tubular fixing base  29 . The valve body  21  is biased by a compression coil spring  23  to a state of closing the valve port  20 K. The small-diameter hole portion  11 S of the stem main body  11  is a core fitting portion to which the valve core  20  (tubular fixing base  29 ) is fitted, and the inner peripheral surface of the small-diameter hole portion  11 S and the outer peripheral surface of the tubular fixing base  29  are sealed. 
     An annular engagement groove  12 U is formed on the outer peripheral surface of the proximal end portion of the elastic seal member  12 . When the tire valve  100  is mounted to the valve mounting hole  81 H of the tire wheel  80 , the elastic seal member  12  is press-fitted into the valve mounting hole  81 H, and the engagement groove  12 U is engaged with an opening edge of the valve mounting hole  81 H. Therefore, a portion of the valve stem  10  on the distal end side of the engagement groove  12 U is a tire outer protruding portion  17  protruding to the outside of the tire  82  (see  FIGS.  2  and  3   ). In the present embodiment, the proximal end of the stem main body  11  is disposed on the distal end side of the valve stem  10  of the engagement groove  12 U. Therefore, the tire outer protruding portion  17  includes the stem main body  11  and part of the elastic seal member  12 . The elastic seal member  12  is made of an insulating elastomer. 
     As illustrated in  FIG.  2   , an inner sleeve  30  is fitted and fixed to the inner side of the stem main body  11 . Specifically, the inner sleeve  30  has a cylindrical shape, is fitted in the straight hole portion  11 B of the stem main body  11 , and is disposed on the proximal end side of the small-diameter hole portion  11 S and the tubular fixing base  29 . 
     As illustrated in  FIG.  4 (B) , the inner sleeve  30  is formed by covering an outer peripheral surface of an inner sleeve main body  31  having conductivity (e.g., made of metal) with an insulating layer  32 . The inner sleeve main body  31  has a cylindrical shape. The insulating layer  32  insulates the inner sleeve main body  31  and the stem main body  11  from each other. 
     Here, the valve stem  10  can connect electric circuits inside and outside the tire  82 . Specifically, as shown in  FIG.  1   , when the valve stem  10  is mounted in the valve mounting hole  81 H, for example, the proximal end portion of the valve stem  10  is connected to cables  98 A and  98 B so as to be connectable to an internal circuit  91  disposed in the tire  82 . The tire outer protruding portion  17  (see  FIG.  2   ) of the valve stem  10  is connected to, for example, cables  99 A and  99 B when a vehicle stops, so as to be connectable to an external circuit  96  disposed outside the tire  82 . 
     Examples of a tire internal device  90  including the internal circuit  91  include a device including a sensor  92  that detects a state of the tire  82  and transmitting a detection result of the sensor  92  by the internal circuit  91 . Such a sensor  92  may be, for example, a pressure sensor that detects the internal pressure of the tire  82  or a temperature sensor. Examples of the tire external device  95  including the external circuit  96  include a power supply device that supplies power to the tire internal device  90 , a receiver that receives detection data of the sensor  92  or the like of the tire internal device  90 , and the like. 
     Hereinafter, a structure of the valve stem  10  for connecting the internal circuit  91  and the external circuit  96  disposed inside and outside the tire  82  will be described. The valve stem  10  includes first and second conductive members including a pair of internal electrodes  11 N and  31 N connected to the internal circuit  91  (i.e., cables  98 A,  98 B) (see  FIG.  6 (A) ) and a pair of external electrodes  11 G and  31 G connected to the external circuit  96  (i.e., cables  99 A,  99 B) (see  FIGS.  4 (A) and  5 (A) ), and being insulated from each other. In the present embodiment, the first and second conductive members are the stem main body  11  and the inner sleeve main body  31 , respectively. 
     As illustrated in  FIG.  6 (A) , in the present embodiment, the pair of internal electrodes  11 N and  31 N connected to the internal circuit  91  (cable  98 A,  98 B) is the proximal end portion of the stem main body  11  and the proximal end portion of the inner sleeve main body  31 , respectively. Connection terminals  51  and  52  of the connector  50  are connected to the distal ends of the cables  98 A and  98 B, respectively, and the connection terminals  51  and  52  abut on the internal electrodes  11 N and  31 N of the valve stem  10 , for example, from the radially inner side. Specifically, the connector  50  has a tubular bracket  53  having one bottomed end, and is screwed with a male thread portion formed on the outer peripheral surface of the proximal end side small-diameter portion  11 A of the stem main body  11  to be fixed to the proximal end portion of the stem main body  11 . The bracket  53  is made of an insulating material such as resin, and insulates the connection terminals  51  and  52  from each other. A vent  50 K is formed at the center of a bottom wall of the bracket  53 . The outer peripheral wall  54  of the bracket  53  is inserted into the annular gap described above formed between the proximal end side small-diameter portion  11 A and the elastic seal member  12 . In the present embodiment, the connection terminals  51  and  52  of the connector  50  are formed of bus bars extending in the axial direction of the valve stem  10 , and for example, the distal end portions of the connection terminals  51  and  52  have hill-shaped bent portions  51 A and  52 A that are bent radially outward of the valve stem  10  and then bent radially inward toward the distal end, where the bent portions  51 A and  52 A facilitate contact with the internal electrodes  11 N and  31 N of the valve stem  10 . In the present embodiment, the proximal end side small-diameter portion  11 A corresponds to an “inner connector coupling portion” described in the claims. 
     Next, the external electrodes  11 G and  31 G of the valve stem  10  connected to the external circuit  96  will be described. As illustrated in  FIGS.  2  and  4   (A), a side surface through-hole  11 K penetrating the inside and outside in the radial direction is formed in a portion of the stem main body  11  exposed from the elastic seal member  12 . The side surface through-hole  11 K is disposed on the proximal end side of the small-diameter hole portion  11 S into which the valve core  20  is fitted in the stem main body  11 . As shown in  FIG.  4 (A) , an opening edge of the side surface through-hole  11 K constitutes one external electrode  11 G of the valve stem  10 . The side surface through-hole  11 K is provided in a portion having a shape obtained by cutting the outer peripheral surface of the stem main body  11  flat, and a flat surface having a quadrangular outer shape is provided at the opening edge of the side surface through-hole  11 K. 
     As illustrated in  FIG.  4 (B) , an insulating layer through-hole  32 K is formed in the insulating layer  32  having a circular tubular shape of the inner sleeve  30  at a position near the distal end of the inner sleeve  30  in the axial direction. As a result, part of the outer peripheral surface of the portion near the distal end of the inner sleeve main body  31  is exposed from the insulating layer through-hole  32 K. Furthermore, the insulating layer through-hole  32 K is provided at a position corresponding to the side surface through-hole  11 K of the valve stem  10 . That is, the insulating layer through-hole  32 K is provided at a position facing the side surface through-hole  11 K in the radial direction of the valve stem  10 . Therefore, a portion of the inner sleeve main body  31  exposed from the insulating layer through-hole  32 K is exposed to the outside from the side surface through-hole  11 K of the stem main body  11 . This exposed portion of the inner sleeve main body  31  constitutes the other external electrode  31 G of the valve stem  10 . The opening diameter of the insulating layer through-hole  32 K is smaller than the opening diameter of the side surface through-hole  11 K of the stem main body  11 , and the entire opening edge of the insulating layer through-hole  32 K is exposed from the side surface through-hole  11 K of the stem main body  11 . The inner sleeve  30  is adhered to the inner surface of the stem main body  11  to seal the side surface through-hole  11 K. 
     As shown in  FIG.  5 (A) , for example, connection terminals  41  and  42  of a connector  40  are respectively connected to the distal ends of the cables  99 A and  99 B from the outside of the tire  82 , and the connection terminals  41  and  42  abut on the external electrodes  31 G and  11 G of the valve stem  10  from the radially outer side. Specifically, as illustrated in  FIGS.  5 (B) and  5 (C) , the connector  40  includes a gasket  45  made of an insulating member that couples and fixes the cables  99 A and  99 B and the connection terminals  41  and  42  (Note that in  FIG.  5 (B) , the inner sleeve  30  is not illustrated). The gasket  45  has a disk-shaped base  43  and has a pair of fitting arcuate protrusions  44  protruding out from an opposing surface of the disk-shaped base  43  to the valve stem  10 . The disk-shaped base  43  abuts on the flat surface of the opening edge of the side surface through-hole  11 K of the stem main body  11 . Then, the distal end portion of one of the connection terminals  41  linearly protruding from the disk-shaped base  43  of the connector  40  abuts on the external electrode  31 G on the outer peripheral surface of the inner sleeve main body  31  through the insulating layer through-hole  32 K. For example, the connection terminal  41  is formed of a bus bar and has a shape in which the distal end portion is bent. In addition, the other connection terminal  42  extending radially outward from the disk-shaped base  43  of the connector  40  along the disk-shaped base  43  abuts on the external electrode  11 G (e.g., the proximal end side opening edge of the side surface through-hole  11 K) of the stem main body  11 . For example, the connection terminal  42  is formed of a bus bar, and has a shape in which a distal end portion is slightly bent toward a side away from the disk-shaped base  43 . This facilitates contact between the connection terminal  42  and the external electrode  11 G of the stem main body  11 . The pair of fitting arcuate protrusions  44  has an arcuate shape along the outer edge of the disk-shaped base  43 , and the outer peripheral surface of the fitting arcuate protrusion  44  is fitted into the side surface through-hole  11 K of the stem main body  11  (the connection terminals  41  and  42  are disposed between the pair of fitting arcuate protrusions  44 ). Note that, for example, if the gasket  45  is formed of an elastomer and the outer peripheral radius of the fitting arcuate protrusion  44  is made larger than the inner peripheral radius of the side surface through-hole  11 K of the stem main body  11 , the attachment of the connector  40  to the valve stem  10  can be stabilized by pushing the fitting arcuate protrusion  44  into the side surface through-hole  11 K. In the present embodiment, the side surface through-hole  11 K of the stem main body  11 , the opening edge (external electrode  11 G) thereof, and the external electrode  31 G constitute a connector coupling portion  13  coupled to the connector  40 . 
     As described above, the valve stem  10  of the present embodiment is connected to the cables  98 A and  98 B and the cables  99 A and  99 B, and connects the internal circuit  91  inside the tire  82  and the external circuit  96  outside the tire  82 . 
     In the valve stem  10  and the tire valve  100  of the present embodiment, the first and second conductive members (stem main body  11  and inner sleeve main body  31 ) insulated from each other are provided, and such first and second conductive members include the internal electrodes  11 N,  31 N connected to the internal circuit  91  in the tire  82  and the external electrodes  11 G,  31 G connected to the external circuit  96  outside the tire  82 , respectively. Here, the external electrodes  11 G and  31 G are disposed on the outer peripheral surface of the tire outer protruding portion  17  of the valve stem  10  protruding outside the tire  82 . As a result, the circuits inside and outside the tire  82  can be connected even in a state where the valve cap  19  is removed from the valve stem  10 . For example, even when the valve cap  19  is removed and air is supplied into the tire  82  through the valve stem  10 , power can be supplied to the internal circuit  91  in the tire  82 . In addition, since the external electrodes  11 G and  31 G are configured independently of the valve core  20 , the internal circuit  91  and the external circuit  96  can be connected regardless of the position of the valve body  21 . 
     In addition, in the valve stem  10 , the outer peripheral surface of the tire outer protruding portion  17  is provided with the pair of external electrodes  11 G and  31 G and includes a connector fitting portion (side surface through-hole  11 K) to which the connector  40  provided in the external circuit  96  is fitted, so that the connector  40  of the external circuit  96  is easily coupled to the stem main body  11 , and connection with the external circuit  96  is facilitated. When the connector  40  is not connected to the external electrodes  11 G,  31 G, a cover member that covers the external electrodes  11 G,  31 G may be attached to the stem main body  11 . 
     In addition, in the valve stem  10 , the pair of external electrodes  11 G and  31 G is disposed on the proximal end side of the small-diameter hole portion  11 S in the tire outer protruding portion  17 , and hence interference with the valve core  20  can be prevented even when the conductive member is disposed on the inner side of the valve stem  10  as in the inner sleeve  30 . 
     Second Embodiment 
       FIG.  7 (A)  shows a valve stem  10 V and a tire valve  100 V including the same of a second embodiment. The valve stem  10 V and the tire valve  100 V are different from the valve stem  10  and the tire valve  100  of the first embodiment in that a stem main body  11 V is made of an insulating resin. The valve stem  10 V has a tubular structure in which a middle portion in the axial direction of the cylindrical stem main body  11  is surrounded by the elastic seal member  12 . Similarly to the first embodiment, the elastic seal member  12  is press-fitted into the valve mounting hole  81 H (see  FIG.  1   ) of the tire wheel  80 , and the stem main body  11 V is provided with the small-diameter hole portion  11 S (see  FIG.  2   ) to which the valve core  20  is fitted, and the valve core  20  is accommodated. In the tire valve  100 V, the valve cap is screwed from the outer side onto the male thread portion provided on the outer peripheral surface of the distal end portion of the stem main body  11 V. 
     In the present embodiment, first and second conductive members  71  and  72  that connect the internal circuit  91  (see  FIG.  1   ) inside the tire  82  and the external circuit  96  outside the tire  82  are embedded in the stem main body  11 V in a state of being insulated from each other. As shown in  FIGS.  7 (A) and  7 (B) , the first and second conductive members  71  and  72  extend linearly in the axial direction of the valve stem  10 V and are arranged, for example, in the circumferential direction, and the proximal end portion disposed in the tire  82  is exposed from the stem main body  11 V. The exposed proximal end portions of the first and second conductive members  71  and  72  are internal electrodes  71 N and  72 N connected to the internal circuit  91  (cables  98 A,  98 B). The first and second conductive members  71  and  72  have an arc shape along the outer peripheral surface of the stem main body  11 V when viewed from the axial direction of the valve stem  10 V (see  FIGS.  8 (A) and  8 (B) ), and are formed of, for example, a metal bus bar. 
     As shown in  FIGS.  7 (A) and  8 (A) , portions of the first and second conductive members  71  and  72  near the distal ends are arranged in the tire outer protruding portion  17  and exposed on the outer peripheral surface of the stem main body  11 V. The exposed portions are a pair of external electrodes  71 G and  72 G connected to the external circuit  96  (cable  99 A,  99 B). Specifically, side surface openings  71 K and  72 K are formed in a recessed manner in an outer peripheral surface of a portion of the stem main body  11 V near the distal end exposed from the elastic seal member  12 , and outer side surfaces of a portion of the first and second conductive members  71  and  72  near the distal end are exposed inside the side surface openings  71 K and  72 K to form the external electrodes  71 G and  72 G. In the present embodiment as well, the side surface openings  71 K and  72 K are formed so as to be fitted with the connector of the external circuit  96 , so that external electrodes  71 G and  72 G can be provided and the connector coupling portion coupled to the connector can be formed on the outer peripheral surface of the stem main body  11 V. 
     Also in the valve stem  10 V and the tire valve  100 V of the present embodiment, since the external electrodes  71 G and  72 G are formed on the outer peripheral surface of the valve stem  10 V, the circuits inside and outside the tire  82  can be connected even in a state where the valve cap is removed. Since the first and second conductive members  71  and  72  are not disposed on the inner side of the stem main body  11 V, they do not interfere with the valve core  20 . Therefore, the external electrodes  71 G and  72 G may be on the distal end side or the proximal end side of the core fitting portion of the valve stem  10 V to which the valve core  20  is fitted, or may be at the same position as the core fitting portion in the axial direction of the valve stem  10 V. 
     Other Embodiments 
     (1) In the first embodiment, the tubular member (inner sleeve main body  31 ) is provided as the conductive member including the internal electrode  31 N and the external electrode  31 G, but may be a rod-shaped member. 
     (2) In the first embodiment, the conductive member (inner sleeve main body  31 ) including the internal electrode  31 N and the external electrode  31 G is provided on the inner side of the stem main body  11 , but may be provided on the outer side. In this case, for example, portions other than the distal end portion and the proximal end portion of the conductive member may be embedded in the elastic seal member  12  to be insulated from the stem main body  11 . The conductive member may be, for example, a rod shape or a circular tubular shape (e.g., concentric with the stem main body  11 ). 
     (3) In the first embodiment, the internal electrode  31 N of the valve stem  10  connected to the internal circuit  91  may be a conductive additional component abutting on the inner sleeve main body  31 . In addition, the internal electrode  11 N of the valve stem  10  connected to the internal circuit  91  may be a conductive additional component abutting on the stem main body  11 . These components include, for example, connection terminals  51  and  52  formed of bus bars, where in this configuration, the connection terminals  51  and  52  are fixed to the stem main body  11  and the inner sleeve main body  31 , respectively, and are provided on the valve stem  10 , instead of being provided on the internal circuit  91  side (cable  98 A,  98 B side). 
     (4) In the first embodiment, the external electrode  11 G of the valve stem  10  connected to the external circuit  96  may be a conductive additional component abutting on the stem main body  11 . In addition, the external electrode  31 G of the valve stem  10  connected to the external circuit  96  may be a conductive component abutting on the inner sleeve main body  31  (e.g., one end portion of a penetrating component may be connected to the inner sleeve main body  31 , and the other end portion may be exposed in the side surface through-hole  11 K). These components include, for example, connection terminals  41  and  42  formed of bus bars, where in this configuration, the connection terminals  41  and  42  are fixed to the inner sleeve main body  31  and the stem main body  11  (e.g., the opening edge of the side surface through-hole  11 K) and are provided on the valve stem  10 , respectively, instead of being provided on the external circuit  96  side (cable  99 A,  99 B side). 
     (5) In the first embodiment, the external electrode  11 G of the stem main body  11  is disposed at the opening edge of the side surface through-hole  11 K, but may not be disposed in the vicinity of the side surface through-hole  11 K (i.e., the vicinity of the external electrode  31 G of the inner sleeve main body  31 ). For example, the external electrode  11 G of the stem main body  11  may be disposed on the outer peripheral surface of the distal end portion of the valve stem  10 . 
     DESCRIPTION OF THE REFERENCE NUMERAL 
       10 ,  10 V Valve stem 
       11 ,  11 V Stem main body 
       11 G External electrode 
       11 N Internal electrode 
       17  Tire outer protruding portion 
       20  Valve core 
       30  Inner sleeve 
       31  Inner sleeve main body 
       31 G External electrode 
       31 N Internal electrode 
       71  First conductive member 
       71 G External electrode 
       71 N Internal electrode 
       72  Second conductive member 
       72 G External electrode 
       72 N Internal electrode 
       80  Tire wheel 
       81 H Valve mounting hole 
       82  Tire 
       91  Internal circuit 
       96  External circuit 
       100 ,  100 V Tire valve