Abstract:
A rigidity measurement device of a tread ring comprises a support jig for detachably holding a tread ring unit. The support jig has an open part for deformably exposing a measurement area, which is one portion of the tread ring, to the exterior, and a restraining part for essentially non-deformably restraining a non-measurement area, which is an area other than the measurement area of the tread ring. The restraining part inhibits deformation of the non-measurement area, whereby stress is no longer generated in the non-measurement area and the rigidity of the measurement area alone can be measured.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a device for measuring tread ring rigidity and a method for measuring uniformity of tread ring. 
       BACKGROUND ART 
       [0002]    Conventionally, in a manufacturing line of pneumatic tires, various characteristics regarding tire uniformity (e.g., RFV, LFV, conicity and the like) are checked before shipment in order to suppress vibration of tires during rolling. When measuring the characteristics regarding tire uniformity, a pneumatic tire is mounted on a measuring rim. For example, vertical rigidity distribution of the tire can be obtained by rotating the rim together with the pneumatic tire on a drum of a uniformity measurement device so that a measurement region of the tire in contact with the drum is moved in the circumferential direction of the tire. 
         [0003]    When a load is applied to the pneumatic tire, the measurement region in contact with the drum deforms greatly. Meanwhile, a non-measurement region of the pneumatic tire which is not in contact with the drum deforms less. Thus, the vertical rigidity distribution of the tire generally depends on rigidity of each measurement region properly. 
         [0004]    On the other hand, airless tires that include a cylindrical tread ring having a ground contact surface, a hub disposed radially inward of the of the tread ring and being fixable to an axle, and a spoke connecting the tread ring and the hub are known. Airless tires are also required to have excellent uniformity, same as pneumatic tires. Uniformity of completed airless tires may be measured similarly to pneumatic tires by mounting the hub to the measurement device. 
         [0005]    Meanwhile, in airless tire, not only eccentric of the tread ring to the hub but also uniformity of the tread ring alone, i.e. vertical rigidity distribution of the tread ring alone in the circumferential direction is believed to affect the uniformity. It is therefore possible to further improve uniformity of airless tires if the vertical rigidity distribution of the tread ring alone is able to be measured. 
         [0006]    When the vertical load is applied to the tread ring alone to measure the vertical rigidity of the measurement region of the tread ring which is in contact with the ground, the tread ring unfortunately deforms in an elliptical shape as the whole so that each part of the tread ring generates stress commensurately. For example, in the measurement region as well as the upward region of the measurement region, the compressive stress is generated on an outer peripheral side of the tread ring, and the tensile stress is generated on an inner circumferential side of the tread ring. On the other hand, in other regions, the tensile stress is generated on the outer peripheral side of the tread ring, and compressive stress is generated on the inner circumferential side. Therefore, not only stress generated in the measurement region which is in contact with the ground but also stress generated in the non-measurement region which is not in contact with the ground influences the measured values as the vertical rigidity. 
         [0007]    Furthermore, since the technique that rotates a tread ring in the circumferential direction while applying vertical load onto the tread ring was not established, it has been therefore difficult to measure rigidity distribution of a whole length of the tread ring effectively. In particular, the technique that effectively measures rigidity distribution in a whole length of tread rings has been strongly desired in order to inspect rigidity of total or sampled tread rings in a manufacturing line of airless tires. 
       SUMMARY OF INVENTION 
     Technical Problem 
       [0008]    The present invention has been made in view of the circumstances described above, and has an object to provide a device for measuring a tread ring rigidity and method for measuring uniformity of a tread ring capable of measuring rigidity of a part in the circumferential direction of the tread ring alone. 
       Solution to Problem 
       [0009]    The present invention provides a rigidity measurement device of a tread ring for measuring rigidity of a part in a circumferential direction of the tread ring alone, wherein the tread ring is to be used for an airless tire comprising the tread ring formed in a cylindrical shape having a ground contact surface, a hub disposed radially inward of the tread ring and being fixable to an axle and a spoke for connecting the tread ring to the hub. The device includes a support jig for supporting the tread ring alone. The support jig includes an opening for exposing the part of the tread ring as a measurement region outwardly in a deformable manner, and a restraint portion for restraining a non-measurement region of the tread ring which is a region except the measurement region in a substantially non-deformable manner. 
         [0010]    In the rigidity measurement device of the present invention, it is preferable that the support jig is configured to hold the tread ring alone detachably. 
         [0011]    In the rigidity measurement device of the present invention, it is preferable that the restraint portion includes an outer supporting portion configured to contact with the ground contact surface of the tread ring in the non-measurement region to restrain the tread ring. 
         [0012]    In the rigidity measurement device of the present invention, it is preferable that the outer supporting portion includes an outer ring configured to contact with the ground contact surface of the tread ring in the non-measurement region continuously. 
         [0013]    In the rigidity measurement device of the present invention, it is preferable that the restraint portion includes an inner supporting portion configured to contact with a radially inner surface of the tread ring in the non-measurement region to restrain the tread ring. 
         [0014]    In the rigidity measurement device of the present invention, it is preferable that the inner supporting portion comprises an inner portion having a column shape configured to contact with the inner surface of the tread ring in the non-measurement region continuously. 
         [0015]    In the rigidity measurement device of the present invention, it is preferable that a ratio Ji/Ro of an inner diameter Ji of the outer supporting portion to an outer diameter Ro of the ground contact surface of the tread ring is of from 0.995 to 1.02. 
         [0016]    In the rigidity measurement device of the present invention, it is preferable that a ratio Jo/Ri of an outer diameter Jo of the inner supporting portion to an inner diameter Ri of the inner surface of the tread ring is of from 0.99 to 1.03. 
         [0017]    In the rigidity measurement device of the present invention, it is preferable that the supporting jig is configured to support the tread ring alone rotatably in the circumferential direction. 
         [0018]    In the rigidity measurement device of the present invention, it is preferable that the restraint portion includes a friction reducing means configured to contact with the non-measurement region to reduce friction to the non-measurement region. 
         [0019]    In the rigidity measurement device of the present invention, it is preferable that the restraint portion includes an outer supporting portion configured to contact with the ground contact surface of the tread ring in the non-measurement region to restrain the tread ring, and the friction reducing means is provided on the outer supporting portion. 
         [0020]    In the rigidity measurement device of the present invention, it is preferable that the friction reducing means includes a plurality of rotatably supported outer rollers each having an outer surface configured to contact with the ground contact surface of the tread ring. 
         [0021]    In the rigidity measurement device of the present invention, it is preferable that the restraint portion includes an inner supporting portion configured to contact with a radially inner surface of the tread ring in the non-measurement region to restrain the tread ring, and the friction reducing means is provided on the inner supporting portion. 
         [0022]    In the rigidity measurement device of the present invention, it is preferable that the friction reducing means includes a plurality of rotatably supported inner rollers each having an outer surface configured to contact with the ground contact surface of the tread ring. 
         [0023]    In the rigidity measurement device of the present invention, it is preferable that a ratio Ji′/Ro of a diameter Ji′ of an arc formed by connecting outer contact points of each outer surface of each outer roller which come into contact with the ground contact surface to an outer diameter Ro of the ground contact surface of the tread ring is of from 0.995 to 1.02. 
         [0024]    In the rigidity measurement device of the present invention, it is preferable that a ratio Jo′/Ri of a diameter Jo′ of an arc formed by connecting inner contact points of each outer surface of each inner roller which come into contact with the inner surface to an inner diameter Ro of the inner surface of the tread ring is of from 0.99 to 1.03. 
         [0025]    In the rigidity measurement device of the present invention, it is preferable that the outer rollers are movable in a radial direction of the tread ring. 
         [0026]    In the rigidity measurement device of the present invention, it is preferable that the inner rollers are movable in a radial direction of the tread ring. 
         [0027]    In the rigidity measurement device of the present invention, it is preferable that the opening of the support jig has a chord length of from 30 to 300 mm. 
         [0028]    The present invention further provides a uniformity measurement method of a tread ring for measuring a circumferential uniformity of rigidity of the tread ring alone, wherein the tread ring is to be used for an airless tire comprising the tread ring formed in a cylindrical shape having a ground contact surface, a hub disposed radially inward of the tread ring and being fixable to an axle and a spoke for connecting the tread ring to the hub. The method includes a holding step of holding the tread ring so that a measurement region that is a part of the tread ring in a circumferential direction is kept in a deformable manner while restraining a non-measurement region of the tread ring that is a region except the measurement region, and a measuring step of measuring a deformed state upon applying load on the measurement region. The holding step and the measuring step are conducted in different position in the circumferential direction of the tread ring by moving the measurement region. 
         [0029]    The present invention further provides a uniformity measurement method of a tread ring for measuring a circumferential uniformity of rigidity of the tread ring alone, wherein the tread ring is to be used for an airless tire comprising the tread ring formed in a cylindrical shape having a ground contact surface, a hub disposed radially inward of the tread ring and being fixable to an axle and a spoke for connecting the tread ring to the hub. The method includes a holding step of holding the tread ring so that a measurement region that is a part of the tread ring in a circumferential direction is in a deformable manner while restraining a non-measurement region of the tread ring that is a region except the measurement region, and a measuring step of measuring a deformed state upon applying load on the measurement region, the measuring step continuously measures a deformed state while moving the measurement region in different position in the circumferential direction of the tread ring by shifting the tread ring in the circumferential direction. 
       Advantageous Effects of Invention 
       [0030]    The rigidity measurement device of a tread ring in accordance with the present invention includes the support jig for supporting the tread ring alone. The support jig includes the opening for exposing a part of the tread ring as the measurement region outwardly in a deformable manner, and the restraint portion for restraining the non-measurement region of the tread ring which is a region except the measurement region. The rigidity of the tread ring is measured by pressing the ground contact surface of the tread ring of the measurement region which exposes through the opening against a drum, plate and the like. At that time, the restraint portion can restrain the non-measurement region of the tread ring in a substantially non-deformable manner. Since stress is not generated in the non-measurement region of the tread ring, it is possible to measure rigidity of just a part in the circumferential direction of the tread ring alone. 
         [0031]    Furthermore, the uniformity measurement method of a tread ring in accordance with the present invention includes the holding step to hold the tread ring and the measuring step to measure a deformed state of the tread ring. In the holding step, the measurement region that is a part of the tread ring in the circumferential direction is kept in a deformable manner while restraining the non-measurement region that is a region except the measurement region. In the measuring step, a deformed state is measured upon applying a load on the measurement region. The holding step and the measuring step are conducted in different position in the circumferential direction of the tread ring by moving the measurement region. Thus, it is possible to measure uniformity of the tread ring alone by measuring a deformed state of a whole length of the tread ring. 
         [0032]    Furthermore, the uniformity measurement method of a tread ring in accordance with the present invention includes the holding step to hold the tread ring and the measuring step to measure a deformed state of the tread ring. In the holding step, the measurement region that is a part of the tread ring in the circumferential direction is kept in deformable manner while restraining the non-measurement region that is a region except the measurement region. In the measuring step, a deformed state is measured upon applying a load on the measurement region. Furthermore, in the measuring step, the measurement region is moved in different position in the circumferential direction of the tread ring by shifting the tread ring in the circumferential direction. Thus, it is possible to measure uniformity of the tread ring alone effectively by measuring a deformed state of a whole length of the tread ring continuously. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0033]      FIG. 1  is a side view illustrating an embodiment of a rigidity measurement device of a tread ring of the present invention. 
           [0034]      FIG. 2  is a perspective view illustrating a support jig of the rigidity measurement device of  FIG. 1 . 
           [0035]      FIG. 3  is an assembled perspective view of the support jig of  FIG. 2 . 
           [0036]      FIG. 4A  is a side view of the support jig of  FIG. 2 , and  FIG. 4B  is a side view of the tread ring. 
           [0037]      FIG. 5  is a side view illustrating a uniformity measurement method of a tread ring of an airless tire using the rigidity measurement device of  FIG. 1 . 
           [0038]      FIG. 6  is a perspective view illustrating the support jig in accordance with another embodiment of the rigidity measurement device of the present invention. 
           [0039]      FIG. 7  is an assembled perspective view of the support jig of  FIG. 6 . 
           [0040]      FIG. 8A  is a side view of the support jig of  FIG. 6 , and  FIG. 8B  is a side view of the tread ring. 
           [0041]      FIG. 9  is an assembled perspective view illustrating a modified example of the support jig of  FIG. 7 . 
           [0042]      FIG. 10  is a side view illustrating another modified example of the support jig of  FIG. 7 . 
           [0043]      FIG. 11  is a sectional view illustrating a supporting structure of outer rollers and inner rollers of  FIG. 7 . 
           [0044]      FIG. 12  is a sectional view illustrating a modified example of the support structure of  FIG. 11 . 
           [0045]      FIG. 13  is a side view illustrating a uniformity measurement method of the tread ring of an airless tire using the support jig of  FIG. 6 . 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0046]    Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. 
         [0047]      FIG. 1  is a side view illustrating an embodiment of a rigidity measurement device  1  of the tread ring (hereinafter, simply referred to as “rigidity measurement device”) of the present invention. As illustrated in  FIG. 1 , the rigidity measurement device  1  in accordance with the present embodiment is a device for measuring rigidity of a part in a circumferential direction of the tread ring  100  alone that is used for an airless tire. 
         [0048]    The rigidity measurement device  1 , for example, includes a support jig  2  for holding the tread ring  100 , a flat plate (road portion)  3  on which the tread ring  100  is to be pressed, a driving unit  4  for driving the support jig  2  toward the flat plate  3  in the vertical direction, a measurement unit  5  that measures vertical force acted on the flat plate  3 , and a processing unit  6  that calculates rigidity of the tread ring  100  based on the force measured by the measurement unit  5 . Here, the tread ring  100  alone is a ring body before being integrated with a spoke and a hub together as an airless tire. 
         [0049]    Instead of the flat plate  3  on which the tread ring  100  is to be pressed, a cylindrical drum may be used. The driving unit  4  can press the tread ring  100  against the flat plate  3  through the support jig  2 . Thus, the tread ring  100 , for example, is given deformation corresponding to vertical flexure of an airless tire. The displacement of the support jig  2  caused by the driving unit  4 , for example, is inputted to the processing unit  6  through the measurement unit  5 . 
         [0050]    The measurement unit  5  may be arranged at the side of the driving unit  4 . The processing unit  6  calculates vertical rigidity of the tread ring  100  based on displacement of the support jig  2  and force measured by the measurement unit  5 . 
         [0051]    The support jig  2  may be drove in lateral or front-back direction by the driving unit  4 . In this case, the measurement unit  5  measures force acted on the flat plate  3  in lateral or front-back direction. 
         [0052]      FIG. 2  and  FIG. 3  illustrate a construction of the support jig  2 . The support jig  2  may hold the tread ring  100  detachably. The support jig  2  includes an opening  21  for exposing the part of the tread ring  100  as a measurement region  100 A outwardly in a deformable manner, and a restraint portion  22  for restraining a non-measurement region  100 B of the tread ring  100  which is a region except the measurement region  100 A in a substantially non-deformable manner. Since the restraint portion  22  restrains the non-measurement region  100 B of the tread ring  100 , stress is not generated in the non-measurement region  100 B of the tread ring  100 . It is therefore possible to measure rigidity of just the measurement region  100 A which is a part in the circumferential direction of the tread ring  100  alone. 
         [0053]    A chord length CL of the opening  21  which exposes the tread ring  100 , for example, is set according to a ground contact length of the airless tire to be measured. In general, passenger cars, which are easy to travel in high speed and are sensitive to vibrations, require better uniformity performance to tires. In view of the above, the chord length CL is preferably in a range of from 30 to 300 mm, for example, in response to a ground contact length of passenger car tires. When the chord length CL is less than 30 mm, it may be difficult to measure rigidity of the tread ring  100  with sufficient load due to excessive short ground contact length. On the other hand, when the chord length CL is more than 300 mm, it may be difficult to prevent the non-measurement region  100 B from deformation because the support jig may not restrain the tread ring  100  in a wide range. 
         [0054]    The restraint portion  22  includes an outer supporting portion  23  disposed outward of the ground contact surface  100 C of the non-measurement region  100 B of the tread ring  100 . The restraint portion  22  also includes an inner supporting portion  24  disposed inward of the inner surface  100 D of the non-measurement region  100 B of the tread ring  100 . 
         [0055]    The outer supporting portion  23  restrains the tread ring  100  from radially outward by contacting with the ground contact surface  100 C of the tread ring  100  in the non-measurement region  100 B. The outer supporting portion  23  includes an outer ring  23 A configured to a circumferentially extending ring shape within the non-measurement region continuously and a side edge plate  23 B disposed axially one end of the outer ring  23 A. 
         [0056]    The outer ring  23 A may contact with a substantially whole range of the ground contact surface  100 C of the tread ring  100  of the non-measurement region  100 B so as to restrain the tread ring  100  from radially outward side. Thus, the substantially whole range of the ground contact surface  100 C of the non-measurement region  100 B of the tread ring  100  is restrained by the outer ring  23 A, and then the non-measurement region  100 B is kept in a non-deformable manner. The outer supporting portion  23  is not limited to the aspect illustrated in  FIG. 3 , but may be formed in a circumferentially intermittent manner arrange radially outward of the non-measurement region  100 B of the tread ring  100 , for example. 
         [0057]    The side edge plate  23 B is integrally formed with the outer ring  23 A to suppress deformation of the outer ring  23 A. The tread ring  100  is mounted in the jig so that one of edges of the tread ring  100  comes into contact with the side edge plate  23 B of the outer supporting portion  23  in a whole range of the non-measurement region  100 B. Thus, eccentricity between the tread ring  100  and the outer supporting portion  23  may be prevented. The side edge plate  23 B has a cut  23 C at a position corresponding to the opening  21 . By providing the cut  23 C on the side edge plate  23 B, it may avoid a contact between the edge of the tread ring  100  and the side edge plate  23 B of the outer supporting portion  23 . Therefore, deformation of the measurement region  100 A is not interrupted. 
         [0058]    The side edge plate  23 B is integrated with the inner supporting portion  24 . A pair of positioning members  23 D for defining the relative position between the outer supporting portion  23  and the inner supporting portion  24  are fixed to the side edge plate  23 B. In this embodiment, the positioning members  23 D are configured as a pair of pins, for example. 
         [0059]      FIG. 4A  is a side view of the support jig  2  of  FIG. 2 , and  FIG. 4B  is a side view of the tread ring  100  in a pre-mounting state to the support jig  2 . When the outer supporting portion  23  and the inner supporting portion  24  are integrated with each other at the proper position, a groove  29  is defined between the outer supporting portion  23  and the inner supporting portion  24 . The non-measurement region  100 B of the tread ring  100  is installed in the groove  29  and is restrained by both the outer supporting portion  23  and the inner supporting portion  24 . 
         [0060]    Preferably, a ratio Ji/Ro of the inner diameter Ji of the outer supporting portion  23 A to the outer diameter Ro of the ground contact surface  100 C of the tread ring  100  is of from 0.995 to 1.02. 
         [0061]    When the ratio Ji/Ro is less than 0.995, it may be difficult to be fitted the tread ring  100  on an radially inner surface of the outer ring  23 A of the outer supporting portion  23 . On the other hand, when the ratio Ji/Ro is more than 1.02, it may be difficult to suppress deformation of the non-measurement region  100 B of the tread ring  100  sufficiently because a gap between the ground contact surface  100 C of the tread ring  100  and an inner surface of the outer ring  23 A of the outer supporting portion  23  becomes large. 
         [0062]    As illustrated in  FIG. 2 , the inner supporting portion  24  restrains the tread ring  100  from radially inward by contacting with the inner surface  100 D of the tread ring  100  in the non-measurement region  100 B. The inner supporting portion  24  includes an inner ring  24 A configured to a column shape having a circumferentially extending outer surface within the non-measurement region continuously. The inner ring  24 A may contact with a substantially whole range of the inner surface  100 D of the tread ring  100  of the non-measurement region  100 B so as to restrain the tread ring  100  from radially inward side. Thus, the substantially whole range of the inner surface  100 D of the non-measurement region  100 B of the tread ring  100  is restrained by the inner ring  24 A, and then the non-measurement region  100 B is kept in the non-deformable manner more effectively. 
         [0063]    As illustrated in  FIG. 3 , the inner ring  24 A has a cut  24 C in a position corresponding to the opening  21 . By providing the cut  24 C on the inner ring  24 A, it may avoid a contact between the tread ring  100  and the inner ring  24 A of the inner supporting portion  24 . Therefore, deformation of the measurement region  100 A is not interrupted. The inner supporting portion  24  is not limited to the aspect illustrated in  FIG. 3 , but may be formed in a circumferentially intermittent manner arranged radially inward of the non-measurement region  100 B of the tread ring  100 , for example. 
         [0064]    The inner supporting portion  24  is integrated with the side edge plate  23 B of the outer supporting portion  23  using a bolt  30  and the like. The bolt  30  may be inserted from a hole  31  provided on an end surface of the inner ring  24 A of the inner supporting portion  24 . The end surface of the inner ring  24 A of the inner supporting portion  24  may be provided with a handle  32  to grip the support jig  2  if necessary. The end surface of the inner ring  24 A of the inner supporting portion  24  may be provided with a flange that comes into contact with an edge of the tread ring  100 , if necessary. The flange may position the tread ring  100  to the support jig  2  in correct position in cooperated with the side edge plate  23 B of the outer supporting portion  23 . 
         [0065]    As illustrated in  FIG. 4 , preferably, a ratio Jo/Ri of the outer diameter Jo of the inner ring  24 A of the inner supporting portion  24  to the inner diameter Ri of the inner surface  100 D of the tread ring  100  is of from 0.99 to 1.03. 
         [0066]    When the ratio Jo/Ri is less than 0.99, it may be difficult to suppress deformation of the non-measurement region  100 B of the tread ring  100  sufficiently because a gap between the inner surface  100 D of the tread ring  100  and an outer surface of the inner ring  24 A of the inner supporting portion  24  becomes large. On the other hand, when the ratio Jo/Ri is more than 1.03, it may be difficult to be fitted the tread ring  100  on the outer surface of the inner ring  24 A of the inner supporting portion  24 . 
         [0067]      FIGS. 5A to 5C  illustrate a uniformity measurement method of the tread ring  100  of an airless tire using the rigidity measurement device  1 . The uniformity measurement method of the tread ring  100  includes a holding step to hold the tread ring  100  and a measuring step to measure a deformed state of the tread ring  100 . 
         [0068]    As illustrated in  FIG. 5A , in the holding step, the tread ring  100  is held by the support jig  2 . That is to say, the tread ring  100  is held so that the non-measurement region  100 B except the measurement region  100 A is restrained by the restraint portion  22  of the support jig  2 . At that time, the measurement region  100 A that is a part in the circumferential direction is exposed from the opening  21  of the support jig  2  in a deformable manner. 
         [0069]    As illustrated in  FIG. 5B , in the measuring step, the support jig  2  is driven by the driving unit  4  to move toward the flat plate  3 , i.e. in the direction of the arrow A 1 , in order to apply a load to the measurement region  100 A of the tread ring  100 . At that time, since the non-measurement region  100 B is kept in the non-deformable manner by the restraint portion  22  of the support jig  2 , only the measurement region  100 A deforms and generate stress. In the measuring step, the displacement of the support jig  2  and the force acted on the flat plate  3  are measured as for a deformed state of the tread ring  100 . 
         [0070]    Then, as illustrated in  FIG. 5C , the support jig  2  is driven in opposite direction to the flat plate  3 , i.e. in the direction of the arrow A 2 , to separate the tread ring  100  from the flat plate  3 . Then, the tread ring  100 , for example, is rotated in the direction of the arrow B in the circumferential direction of the tread ring  100  with respect to the support jig  2 . Thus, new measurement region  100 A is set by shifting the previous measurement region  100 A with a rotational angle. That is, the measurement region  100 A is moved in different position in the circumferential direction of the tread ring  100 . When it is difficult to rotate the tread ring  100  due to friction among the tread ring  100 , the outer supporting portion  23  and the inner supporting portion  24 , the tread ring  100  may be shifted by removing the inner supporting portion  24  from the outer supporting portion  23 . Since then a deformed state of the tread ring  100  over the entire length is measured by repeating the processes illustrated in  FIGS. 5A to 5C . 
         [0071]      FIG. 6  and  FIG. 7  illustrate a configuration of the support jig  2 A in accordance with another embodiment of the invention. In the rigidity measurement device in accordance with the present embodiment, the configuration of the rigidity measurement apparatus illustrated in  FIGS. 1 to 5  described above may be employed as a portion or element that is not described below. 
         [0072]    The support jig  2 A can support the tread ring  100  detachably. The support jig  2 A includes the opening  21  to expose the measurement region  100 A of the tread ring  100  outwardly in a deformable manner and the restraint portion  22  for restraining the non-measurement region  100 B of the tread ring  100  in a substantially non-deformable manner. The restraint portion  22  includes the outer supporting portion  23  disposed outward of the ground contact surface  100 C of the non-measurement region  100 B, the inner supporting portion  24  disposed inward of the inner surface  100 D of the non-measurement region  100 B and friction reducing means  25  and  26  for reducing friction against the non-measurement region  100 B. 
         [0073]    The outer supporting portion  23  can restrain the non-measurement region  100 B of the tread ring  100  from the radially outward side. The outer supporting portion  23  includes the outer ring  23 A and the side edge plate  23 B disposed axially one end of the outer ring  23 A as illustrated in  FIG. 7 . The inner side of the outer supporting portion  23  is provided with the friction reducing means  25 . 
         [0074]    The outer ring  23 A supports the friction reducing means  25 . The side edge plate  23 B is integrated with the outer ring  23 A to suppress deformation of the outer ring  23 A. The side edge plate  23 B is fixed to the inner supporting portion  24 . 
         [0075]    The side edge plate  23 B has the cut  23 C in the position corresponding to the opening  21 . The side edge plate is provided with the positioning members  23 D in a projection manner. 
         [0076]    The friction reducing means  25  includes a rotatably supported outer roller  27 . A plurality of the outer rollers  27  are spaced in the circumferential direction with a gap. The outer rollers  27  include outer surfaces  27   a  that circumscribe the ground contact surface  100 C of the tread ring  100 . The outer supporting portion  23  restrains the ground contact surface  100 C of the non-measurement region  100 B of the tread ring  100  from radially outward side through the outer rollers  27 . 
         [0077]    The friction reducing means  25  may include a so-called endless track shape of a belt may be provided in addition to the above mentioned outer roller  27 , for example. 
         [0078]    As illustrated in  FIG. 6 , the inner supporting portion  24  restrains the non-measurement region  100  of the tread ring  100  from radially inner side. The inner supporting portion  24  is configured as the inner ring  24 A in a column shape (see  FIG. 7 ). The inner supporting portion  24  is provided with the friction reducing means  26  on its radially outer side. The friction reducing means  26  is supported by the inner ring  24 A. 
         [0079]    The friction reducing means  26  includes a rotatably supported inner roller  28 . A plurality of the inner rollers  28  are spaced in the circumferential direction with a gap. The inner rollers  28  include outer surfaces  28   a  that is inscribed in the inner surface  100 D of the tread ring  100 . The inner supporting portion  24  restrains the inner surface  100 D of the non-measurement region  100 B of the tread ring  100  from radially inward side through the inner rollers  27 . 
         [0080]    The friction reducing means  26  may include a so-called endless track shape of a belt may be provided in addition to the above mentioned inner rollers  28 , for example. 
         [0081]    In this embodiment, since the restraint portion  22  is provided with the friction reducing means  25  and  26  for reducing friction against the non-measurement region  100 B of the tread ring  100 , the tread ring  100  is easy to be shifted in the circumferential direction while restraining the non-measurement region  100 B in the support jig  2 A. Thus, the measurement region moves in different position in the circumferential direction of the tread ring  100 . Accordingly, it is possible to measure the rigidity of just a measurement region  100 A over the entire length continuously and effectively without removing the tread ring  100  from the support jig  2 A. 
         [0082]    The support jig  2 A may be configured to include either one of the friction reducing means  25  or  26  to restrain the tread ring  100 . However, it is preferable that the friction reducing means  25  and  26  are positioned on the outer and inner sides of the tread ring  100  as the present embodiment in order to suppress the deformation of the tread ring  100  restrained and to rotate the tread ring  100  smoothly. 
         [0083]    As illustrated in  FIG. 7 , the inner ring  24 A has the cut  24 C in the position corresponding to the opening  21 . 
         [0084]    The inner supporting portion  24  is integrated with the outer supporting portion  23  using the blot  30  and the like, for example. The inner supporting portion  24  is provided with the handle  32  on an end surface of the inner ring  24 A, if necessary. 
         [0085]      FIG. 8A  illustrates a side view of the support jig  2 A, and  FIG. 8B  illustrates a side view of the tread ring  100  before attaching to the support jig  2 A. When the outer supporting portion  23  and the inner supporting portion  24  are fixed with each other in a proper relative position, the outer rollers  27  and the inner rollers  28  arranged on respective circumferential lines along the circumferential direction of the tread ring  100  so that the outer rollers  27  and the inner rollers  28  face one another. Thus, the tread ring  100  is restrained between the outer rollers  27  and the inner rollers  28  to suppress deformation of the tread ring  100  effectively. 
         [0086]    Preferably, a ratio Ji′/Ro is of from 0.995 to 1.02, where “Ji” is a diameter of an arc C 1  formed by connecting outer contact points  27   b  of each outer surface  27   a  of each outer roller  27  which come into contact with the ground contact surface  100 C of the tread ring  100 , and “Ro” is an outer diameter of the ground contact surface  100 C of the tread ring  100 . 
         [0087]    When the ratio Ji′/Ro is less than 0.995, it may be difficult to install the tread ring  100  into a space of radially inward of the outer supporting portion  23 . On the other hand, when the ratio Ji′/Ro is more than 1.02, since a gap between the ground contact surface  100 C of the tread ring  100  and outer surfaces  27   a  of the outer rollers  27  becomes large, it may be difficult to restrain the non-measurement region  100 B of the tread ring  100  sufficiently. 
         [0088]    The outer contact points  27   b  mean positions that are nearest to an axis of the tread ring  100  (the outer ring  23 A) on the outer surfaces  27   a  of the outer rollers  27 . 
         [0089]    Preferably, a ratio Jo′/Ri is of from 0.99 to 1.03, where “Jo” is a diameter of an arc C 2  formed by connecting inner contact points  28   b  of each outer surface  28   a  of each inner roller  28  which come into contact with the inner surface  100 D of the tread ring  100 , and “Ro” is an inner diameter of the inner surface  100 D of the tread ring  100 . 
         [0090]    When the ratio Jo′/Ri is less than 0.99, since a gap between the inner surface  100 D of the tread ring  100  and the outer surfaces  28   a  of the inner rollers  28  becomes large, it may be difficult to restrain the non-measurement region  100 B of the tread ring  100  sufficiently. On the other hand, when the ratio Jo′/Ri is more than 1.03, it may be difficult to install the tread ring  100  into a space of radially outward of the inner supporting portion  24 . Furthermore, it may be difficult to rotate the tread ring  100  in the support jig  2 A. 
         [0091]    The inner contact points  28   b  mean positions that are farthest from the axis of the tread ring  100  (the inner ring  24 A) on the outer surfaces  28   a  of the inner rollers  28 . 
         [0092]    The inner supporting portion  24  exposes the measurement region  100 A of the tread ring  100  from a space between a pair of inner contact points  28   b  of the inner rollers  28  arranged on both sides of the opening  21 . That is, the opening  21  of the support jig  2 A exposes the tread ring  100  in the chord length CL which is a distance between a pair of inner contact points  28   b  of the inner rollers  28  arranged on both sides of the opening  21 . 
         [0093]    The chord length CL which exposes the tread ring  100 , for example, is set according to a ground contact length of the airless tire to be measured. The chord length CL in accordance with the present embodiment is preferably in a range of from 30 to 300 mm, for example, same as the embodiment illustrated in  FIG. 2 . 
         [0094]      FIG. 9  illustrates the support jig  2 X which is a modified example of the support jig  2 A illustrated in  FIG. 7 . The support jig  2 X includes the outer supporting portion  23 X and the inner supporting portion  24 X. 
         [0095]    The outer supporting portion  23 X is different from the outer supporting portion  23  in that the outer rollers  27  are provided on the inner side of the outer ring  23 A almost without a gap. Similarly, the inner supporting portion  24 X is different from the inner supporting portion  24  in that the inner rollers  28  are provided on the outer side of the inner ring  24 A almost without a gap. 
         [0096]    According to the support jig  2 X, since a lot of outer rollers  27  and inner rollers  28  are able to come into contact with the tread ring  100  to restrain the tread ring  100  in a wide range, deformation of the non-measurement region  100 B can further be suppressed. In addition, the tread ring  100  can rotate more smoothly within the support jig  2 A. 
         [0097]      FIG. 10  illustrates the support jig  2 Y which is another modified example of the support jig  2 X illustrated in  FIG. 7 . The support jig  2 Y includes the outer supporting portion  23 Y and the inner supporting portion  24 Y. 
         [0098]    In the support jig  2 Y, the number of the inner rollers  28  provided on the inner supporting portion  24 Y is less than the number of the outer rollers  27  provided on the outer supporting portion  23 Y. Furthermore, each inner roller  28  is located between a pair of circumferentially adjacent outer rollers  27  in a staggered manner, i.e. the outer rollers  27  and the inner rollers  28  are alternately arranged. These features are different from the support jig  2 A. 
         [0099]    According to the support jig  2 Y, friction between the ground contact surface  100 C and the restraint portion  22  can further be reduced while suppressing deformation of the non-measurement region  100 B of the tread ring  100 . In the support jig  2 Y, the outer roller  27  and the inner roller  28  may be installed more, similar to the support jig  2 X. 
         [0100]      FIG. 11  illustrates a supporting structure  40  of the outer roller  27  and the inner roller  28 . 
         [0101]    The outer roller  27 , for example, is rotatably supported while using a supporting axis  41 , bearings  42  and  43 , and a supporting plate  44  and the like. One end of the supporting axis  41  is supported by the side edge plate  23 B of the outer supporting portion  23 , and the other end thereof is supported by the supporting plate  44 . The supporting axis  41  rotatably supports the outer roller  27  through the bearings  42  and  43 . 
         [0102]    The bearings  42  and  43  are disposed on both ends of the outer roller  27 . In this embodiment, the configuration that the outer roller  27  rotates around the fixed supporting axis  41  is disclosed. Alternatively, the configuration that the outer roller  27  rotates together with the supporting axis  41  by providing the bearings  42  and  43  on the side edge plate  23 B and the supporting plate  44  respectively may be employed. 
         [0103]    The supporting plate  44  is fixed to the end surface of the outer ring  23 A of the outer supporting portion  23  using a bolt  45  and the like, for example. As illustrated in  FIG. 7 , although the supporting plate  44  of the embodiment is formed continuously in the circumferential direction of the outer ring  23 A, it may be divided into a plurality of pieces. 
         [0104]    According to the supporting structure  40  illustrated in  FIG. 11 , the outer roller  27  can rotate smoothly while restraining the ground contact surface  100 C of the tread ring  100 . Thus, friction in the circumferential direction between the ground contact surface  100 C of the non-measurement region  100 B and the outer supporting portion  23  can be reduced. 
         [0105]    The inner roller  28 , for example, is also rotatably supported while using a supporting axis  46 , bearings  47  and  48 , and supporting plates  49  and  50  and the like, similar to the outer roller  27 . One end of the supporting axis  46  is supported by the supporting plate  49 , and the other end thereof is supported by the supporting plate  50 . In this embodiment, the configuration that the inner roller  28  rotates around the fixed supporting axis  46  is disclosed. Alternatively, the configuration that the inner roller  28  rotates together with the supporting axis  46  by providing the bearings  47  and  48  on the supporting plates  49  and  50  respectively may be employed. 
         [0106]    The supporting plates  49  and  50  are fixed to both end surfaces of the inner ring  24 A of the inner supporting portion  24  using blots  51  and  52 , for example. As illustrated in  FIG. 7 , although the supporting plates  49  and  50  are formed continuously in the circumferential direction of the inner ring  24 A, it may be divided into a plurality of pieces. 
         [0107]    According to the supporting structure  40  illustrated in  FIG. 11 , the inner roller  28  can rotate smoothly while restraining the inner surface  100 D of the tread ring  100 . Thus, friction in the circumferential direction between the inner surface  100 D of the non-measurement region  100 B and the inner supporting portion  24  can be reduced. 
         [0108]      FIG. 12  illustrates the supporting structure  40 X which is a modified example of the supporting structure  40 . In the supporting structure  40 X, the outer roller  27  and the inner roller  28  are configured to move in the radial direction R 1  or R 2  of the tread ring  100 . This feature is different from the supporting structure  40  illustrated in  FIG. 11 . 
         [0109]    In the supporting structure  40 X, the supporting plate  44  is divided into a plurality of pieces in the circumferential direction of the outer ring  23 A. Similarly, the supporting plates  49  and  50  are divided into a plurality of pieces in the circumferential direction of the inner ring  24 A. In the supporting structure  40 X, by moving the positions of the supporting axis  41  and the supporting plate  44  relative to the outer ring  23 A and the side edge plate  23 B respectively in the radial direction R 1  or R 2 , the outer roller  27  can move. In order to move the outer roller  27 , the side edge plate  23 B is provided with a slot  61  extending in the radial direction long R 1  and R 2 , for example. similarly, the supporting plate  44  is provided with a slot  62  extending in the radial direction R 1  and R 2 . By moving the supporting plate  44  together with the supporting axis  41  along the slot  61  and the slot  62 , the outer roller  27  can move in the radial direction R 1  or R 2  of the tread ring  100 . 
         [0110]    Similarly, in the supporting structure  40 X, the inner roller  28  can move by shifting the positions of the supporting plates  49  and  50  relative to the inner ring  24 A in the radial direction R 1  or R 2  of the tread ring  100 . In order to move the inner roller  28 , the supporting plate  49  is provided with a slot  63  extending in the radial direction R 1  and R 2  through which the blot  51  is inserted, for example. The inner roller  28  can be moved in the radial direction R 1  or R 2  of the tread ring  100  by moving the supporting plates  49  and  50  along the slot  63  and the slot  64  respectively with loosening the blots  51  and  52 . 
         [0111]    As the structure where the outer roller  27  is movably supported in the radial direction R 1  or R 2  of the tread ring  100  other than the above supporting structure  40 X, the hole to which the supporting axis  41  is to be inserted may be formed on the supporting plate  44  in a slot shape extending in the radial direction R 1  and R 2 . Similarly, the hole to which the supporting axis  46  may be formed on the respective supporting plates  49  and  50  in a slot shape. 
         [0112]    In the supporting structure  40 X, since the outer roller  27  and the inner roller  28  are configured to move in the radial direction R 1  or R 2  of the tread ring  100 , the respective contact pressure of the outer roller  27  and the inner roller  28  against the tread ring  100  can be adjusted exactly. Thus, it is possible to adjust balance between the degree of deformation of the non-measurement region  100 B of the tread ring  100  and the friction among the outer roller  27 , the inner roller  28  and the tread ring  100 . Furthermore, tread ring  100  with different size may be installed into the support jig  2 A by setting a moving range of the outer roller  27  and the inner roller  28  properly, and therefore the non-measurement region  100 B thereof is substantially restrained through the outer roller  27  and the inner roller  28  in a non-deformable manner. Accordingly, rigidity of the tread ring  100  with different size can be measured without exchanging the outer supporting portion  23  and the inner supporting portion  24 , thereby improving working efficiency. 
         [0113]    In the supporting structure  40  and the supporting structure  40 X, an elastic member such as a spring may be employed so that the outer roller  27  is energized radially inward of the tread ring  100  and the inner roller  28  is energized radially outward of the tread ring  100 . 
         [0114]      FIGS. 13A to 13B  illustrate a uniformity measurement method of the tread ring  100  of an airless tire using the rigidity measurement device  1 . The uniformity measurement method of the tread ring  100  includes a holding step for holding the tread ring  100  and measuring step for measuring a deformed state of the tread ring  100 . 
         [0115]    As illustrated in  FIG. 13A , in the holding step, the tread ring  100  is held by the support jig  2 . That is to say, the tread ring  100  is held so that the non-measurement region  100 B except the measurement region  100 A is restrained by the restraint portion  22  of the support jig  2 A. At that time, the measurement region  100 A that is a part in the circumferential direction is exposed from the opening  21  of the support jig  2 A in a deformable manner. 
         [0116]    As illustrated in  FIG. 13B , in the measuring step, the support jig  2 A is driven by the driving unit  4  to move toward the flat plate  3 , i.e. in the direction of the arrow A 1 , in order to apply a load to the measurement region  100 A of the tread ring  100 . At that time, since the non-measurement region  100 B is kept in a non-deformable manner by the restraint portion  22  of the support jig  2 A, only the measurement region  100 A deforms and generate stress. In the measuring step, the displacement of the support jig  2 A and the force acted on the flat plate  3  are measured as for a deformation state of the tread ring  100 . 
         [0117]    Then, as illustrated in  FIG. 13C , the support jig  2 A is driven in a travel direction of the tread ring  100 , i.e. in the direction of the arrow D. As a result, the tread ring  100  rotates in the direction of the arrow C so that the measurement region  100 A moves in different position in the circumferential direction of the tread ring  100 . At that time, the outer rollers  27  and the inner rollers  28  which support the tread ring  100  rotate in directions of the arrows B 1  and B 2  respectively to reduce friction between the non-measurement region  100 B of the tread ring  100  and the restraint portion  22 . Thus, it is possible to rotate the tread ring  100  without removing the inner supporting portion  24  from the outer supporting portion  23 . As described above, since a deformed state of the tread ring  100  over the entire length is measured continuously by moving the support jig  2 A in the direction of the arrow D until the tread ring  100  rotates at least once, it is possible to measure the uniformity of the tread ring alone efficiently. 
         [0118]    In this embodiment, although a deformed state of the tread ring  100  over the entire length is measured by moving the support jig  2 A with respect to the fixed flat plate  3 , it may alternatively be configured that the flat plate  3  moves with respect to the fixed support jig  2 A. In another embodiment, when a drum is used instead of the flat plate  3 , a deformed state of the tread ring  100  over the entire length may be measured while rotating the drum. 
         [0119]    While the measurement device of a tread ring and the uniformity measurement method of a tread ring of the present invention have been described in detail, the present invention is not limited to the embodiments as illustrated, but it may be carried out by modifying to various aspects. 
       EXAMPLE 
       [0120]    The rigidity measurement device of a tread ring with the support jig having a basic structure illustrated in  FIG. 2  was manufactured, and then vertical rigidity of the tread ring alone was measured. As for a comparative example, the vertical rigidity of the tread ring alone was measured without using the support jig. Upon measuring the vertical rigidity, the loads corresponding to 50%, 100% and 120% of the load index of a pneumatic tire which is equivalent to the airless tire to be measured in view of specifications, e.g. an outer diameter, a width and the like, were applied. 
         [0121]    Evaluation of the rigidity measurement propriety “S” means that the vertical rigidity was able to measure in the condition where only the measurement region deforms. Evaluation of the rigidity measurement propriety “A” means that the vertical rigidity measured is believed to depend almost on the rigidity of the measurement region in spite of a part of the non-measurement region slightly deforming. Evaluation of the rigidity measurement propriety “B” means that the vertical rigidity was measured in the condition where only the measurement region deforms, but attaching and detaching work of the tread ring was difficult. Evaluation of the rigidity measurement propriety “C” means that the vertical rigidity was not able to be measured by the applied load due to less deformation of the tread ring. Evaluation of the rigidity measurement propriety “D” means that the measured vertical rigidity significantly depends on the rigidity of the non-measurement region since almost entire region of the tread ring deformed. 
         [0000]    
       
         
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
             
             
               
                   
                 Ref. 
                 Ex. 1 
                 Ex. 2 
                 Ex. 3 
                 Ex. 4 
               
               
                   
               
               
                 Support jig 
                 None 
                 Presence 
                 Presence 
                 Presence  
                 Presence 
               
               
                 Outer supporting portion 
                 None 
                 Presence  
                 Presence 
                 Presence  
                 Presence 
               
               
                 Inner supporting portion 
                 None 
                 Presence 
                 None 
                 Presence  
                 Presence 
               
               
                 CL (mm) 
                 — 
                 60 
                 60 
                 20 
                 30 
               
               
                 Ji/Ro 
                 — 
                  1 
                  1 
                  1 
                  1 
               
               
                 Jo/Ri 
                 — 
                  1 
                  1 
                  1 
                  1 
               
             
          
           
               
                 Stiffness 
                 50% load 
                 D 
                 S 
                 S 
                 S 
                 S 
               
               
                 measurement 
                 100% load 
                 D 
                 S 
                 S 
                 C 
                 S 
               
               
                 propriety 
                 120% load 
                 D 
                 S 
                 A 
                 C 
                 C 
               
               
                   
               
             
          
           
               
                   
                 Ex. 5 
                 Ex. 6 
                 Ex. 7 
                 Ex. 8 
                 Ex. 9 
               
               
                   
               
               
                 Support jig 
                 Presence  
                 Presence 
                 Presence  
                 Presence  
                 Presence 
               
               
                 Outer supporting portion 
                 Presence  
                 Presence 
                 Presence  
                 Presence 
                 Presence 
               
               
                 Inner supporting portion 
                 Presence 
                 Presence 
                 Presence 
                 Presence 
                 Presence 
               
               
                 CL (mm) 
                 300 
                 400 
                 60 
                 60 
                 60 
               
               
                 Ji/Ro 
                  1 
                  1 
                  0.99 
                  0.995 
                  1.02 
               
               
                 Jo/Ri 
                  1 
                  1 
                  1 
                  1 
                  1 
               
             
          
           
               
                 Stiffness 
                 50% load 
                 S 
                 S 
                 B 
                 S 
                 S 
               
               
                 measurement 
                 100% load 
                 S 
                 A 
                 B 
                 S 
                 S 
               
               
                 propriety 
                 120% load 
                 A 
                 A 
                 B 
                 S 
                 S 
               
               
                   
               
             
          
           
               
                   
                 Ex. 10 
                 Ex. 11 
                 Ex. 12 
                 Ex. 13 
                 Ex. 14 
               
               
                   
               
               
                 Support jig 
                 Presence 
                 Presence 
                 Presence 
                 Presence 
                 Presence 
               
               
                 Outer supporting portion 
                 Presence 
                 Presence 
                 Presence 
                 Presence 
                 Presence 
               
               
                 Inner supporting portion 
                 Presence 
                 Presence 
                 Presence 
                 Presence 
                 Presence 
               
               
                 CL (mm) 
                 60 
                 60 
                 60 
                 60 
                 60 
               
               
                 Ji/Ro 
                  1.04 
                  1 
                  1 
                  1 
                  1 
               
               
                 Jo/Ri 
                  1 
                  0.98 
                  0.99 
                  1.03 
                  1.05 
               
             
          
           
               
                 Stiffness 
                 50% load 
                 S 
                 S 
                 S 
                 S 
                 B 
               
               
                 measurement 
                 100% load 
                 A 
                 A 
                 S 
                 S 
                 B 
               
               
                 propriety 
                 120% load 
                 A 
                 A 
                 S 
                 S 
                 B 
               
               
                   
               
             
          
         
       
     
         [0122]    As clearly shown in Table 1, it is confirmed that the device for measuring rigidity of the tread ring according to the embodiment can measure the rigidity of the measurement region correctly as compared with the comparative example. 
         [0123]    The rigidity measurement device of a tread ring with the support jig having a basic structure illustrated in  FIG. 6  was manufactured, and then vertical rigidity of the tread ring alone was measured. As for comparative example 1, the vertical rigidity of the tread ring alone was measured without using the support jig. As for comparative example 2, the vertical rigidity of the tread ring alone was measured using the support jig without having the friction reducing means. Upon measuring the vertical rigidity, the loads corresponding to 50%, 100% and 120% of the load index of a pneumatic tire which is equivalent to the airless tire to be measured in view of specifications, e.g. an outer diameter, a width and the like, were applied. 
         [0124]    Evaluation of the rigidity measurement propriety “S” means that the vertical rigidity was measured properly and continuously in the condition where only the measurement region deforms with a smooth rotation of the tread ring. Evaluation of the rigidity measurement propriety “A” means that the tread ring rotated easily and the vertical rigidity measured is believed to depend almost on the rigidity of the measurement region in spite of a part of the non-measurement region slightly deforming. Evaluation of the rigidity measurement propriety “B” means that the vertical rigidity was not able to be measured by the applied load due to less deformation of the tread ring although the tread ring smoothly rotated. Evaluation of the rigidity measurement propriety “C” means that the vertical rigidity was measured properly in spite of some difficulty in rotation of the tread ring. Evaluation of the rigidity measurement propriety “D” means that the vertical rigidity was not able to be measured continuously since the tread ring failed to rotate. Evaluation of the rigidity measurement propriety “E” means that the measured vertical rigidity significantly depends on the rigidity of the non-measurement region since almost entire region of the tread ring deformed. 
         [0000]    
       
         
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                 TABLE 2 
               
               
                   
               
             
             
               
                   
                 Ref. 1 
                 Ref. 2 
                 Ex. 1 
                 Ex. 2 
                 Ex. 3 
               
               
                   
               
               
                 Support jig 
                 None 
                 Presence 
                 Presence 
                 Presence 
                 Presence 
               
               
                 Friction reducing means 
                 None 
                 None 
                 Presence  
                 Presence 
                 Presence 
               
               
                 Outer supporting portion 
                 None 
                 None 
                 Presence 
                 Presence 
                 Presence 
               
               
                 Inner supporting portion 
                 None 
                 None 
                 Presence 
                 None 
                 Presence 
               
               
                 CL (mm) 
                 — 
                 60 
                 60 
                 60 
                 20 
               
               
                 Ji′/Ro 
                 — 
                  1 
                  1 
                  1 
                  1 
               
               
                 Outer roller movement 
                 — 
                 — 
                 No 
                 No 
                 No 
               
               
                 Inner roller movement 
                 — 
                 — 
                 No 
                 No 
                 No 
               
               
                 Jo′/Ri 
                 — 
                  1 
                  1 
                  1 
                  1 
               
             
          
           
               
                 Stiffness 
                 50% load 
                 E 
                 D 
                 S 
                 S 
                 S 
               
               
                 measurement 
                 100% load 
                 E 
                 D 
                 S 
                 S 
                 B 
               
               
                 propriety 
                 120% load 
                 E 
                 D 
                 S 
                 A 
                 B 
               
               
                   
               
             
          
           
               
                   
                 Ex. 4 
                 Ex. 5 
                 Ex. 6 
                 Ex. 7 
                 Ex. 8 
               
               
                   
               
               
                 Support jig 
                 Presence  
                 Presence 
                 Presence  
                 Presence 
                 Presence 
               
               
                 Friction reducing means 
                 Presence 
                 Presence 
                 Presence 
                 Presence 
                 Presence 
               
               
                 Outer supporting portion 
                 Presence 
                 Presence 
                 Presence  
                 Presence 
                 Presence 
               
               
                 Inner supporting portion 
                 Presence  
                 Presence 
                 Presence 
                 Presence 
                 Presence 
               
               
                 CL (mm) 
                 30 
                 300 
                 400 
                 60 
                 60 
               
               
                 Ji′/Ro 
                  1 
                  1 
                  1 
                  0.99 
                  0.995 
               
               
                 Outer roller movement 
                 No 
                 No 
                 No 
                 No 
                 No 
               
               
                 Inner roller movement 
                 No 
                 No 
                 No 
                 No 
                 No 
               
               
                 Jo′/Ri 
                  1 
                   1 
                   1 
                  1 
                  1 
               
             
          
           
               
                 Stiffness 
                 50% load 
                 S 
                 S 
                 S 
                 C 
                 S 
               
               
                 measurement 
                 100% load 
                 S 
                 S 
                 A 
                 C 
                 S 
               
               
                 propriety 
                 120% load 
                 B 
                 A 
                 A 
                 C 
                 S 
               
               
                   
               
             
          
           
               
                   
                 Ex. 9 
                 Ex. 10 
                 Ex. 11 
                 Ex. 12 
                 Ex. 13 
               
               
                   
               
               
                 Support jig 
                 Presence  
                 Presence 
                 Presence  
                 Presence 
                 Presence 
               
               
                 Friction reducing means 
                 Presence  
                 Presence 
                 Presence  
                 Presence 
                 Presence 
               
               
                 Outer supporting portion 
                 Presence  
                 Presence 
                 Presence 
                 Presence 
                 Presence 
               
               
                 Inner supporting portion 
                 Presence 
                 Presence 
                 Presence 
                 Presence 
                 Presence 
               
               
                 CL (mm) 
                 60 
                 60 
                 60 
                 60 
                 60 
               
               
                 Ji′/Ro 
                  1.02 
                  1.04 
                  1 
                  1 
                  1 
               
               
                 Outer roller movement 
                 No 
                 No 
                 No 
                 No 
                 No 
               
               
                 Inner roller movement 
                 No 
                 No 
                 No 
                 No 
                 No 
               
               
                 Jo′/Ri 
                  1 
                  1 
                  0.98 
                  0.99 
                  1.03 
               
             
          
           
               
                 Stiffness 
                 50% load 
                 S 
                 S 
                 S 
                 S 
                 S 
               
               
                 measurement 
                 100% load 
                 S 
                 A 
                 A 
                 S 
                 S 
               
               
                 propriety 
                 120% load 
                 S 
                 A 
                 A 
                 S 
                 S 
               
               
                   
               
             
          
           
               
                   
                 Ex. 14 
                   
                 Ex. 15  
                   
                 Ex. 16 
               
               
                   
               
               
                 Support jig 
                 Presence 
                   
                 Presence 
                   
                 Presence 
               
               
                 Friction reducing means  
                 Presence 
                   
                 Presence 
                   
                 Presence 
               
               
                 Outer supporting portion 
                 Presence 
                   
                 Presence 
                   
                 Presence 
               
               
                 Inner supporting portion 
                 Presence 
                   
                 Presence 
                   
                 Presence 
               
               
                 CL (mm) 
                 60 
                   
                 60 
                   
                 60 
               
               
                 Ji′/Ro 
                  1.05 
                   
                  1 
                   
                  1 
               
               
                 Outer roller movement 
                 No 
                   
                 Yes 
                   
                 Yes 
               
               
                 Inner roller movement 
                 No 
                   
                 Yes 
                   
                 Yes 
               
               
                 Jo′/Ri 
                  1 
                   
                  1 
                   
                  1 
               
             
          
           
               
                 Stiffness 
                 50% load 
                 C 
                   
                 S 
                   
                 S 
               
               
                 measurement 
                 100% load 
                 C 
                   
                 S 
                   
                 S 
               
               
                 propriety 
                 120% load 
                 C 
                   
                 S 
                   
                 S 
               
               
                   
               
             
          
         
       
     
         [0125]    As clearly shown in Table 2, it is confirmed that the device for measuring rigidity of the tread ring according to the embodiment can measure the rigidity of the measurement region correctly and continuously as compared with the comparative example. 
       REFERENCE SIGNS LIST 
       [0000]    
       
           1  Rigidity measurement device 
           2  Support jig 
           2 A Support jig 
           3  Flat plate 
           21  Opening 
           22  Restraint portion 
           23  Outer supporting portion 
           23 A Outer ring 
           24  Inner supporting portion 
           24 A Inner ring 
           100  Tread ring 
           100 A Measurement region 
           100 B Non-measurement region